1
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Cancelarich NL, Arrulo M, Gugliotti ST, Barbosa EA, Moreira DC, Basso NG, Pérez LO, Teixeira C, Gomes P, de la Torre BG, Albericio F, Eaton P, Leite JRSA, Marani MM. First Bioprospecting Study of Skin Host-Defense Peptides in Odontophrynus americanus. JOURNAL OF NATURAL PRODUCTS 2024; 87:1714-1724. [PMID: 38900961 DOI: 10.1021/acs.jnatprod.4c00184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Abstract
The adaptation of amphibians to diverse environments is closely related to the characteristics of their skin. The complex glandular system of frog skin plays a pivotal role in enabling these animals to thrive in both aquatic and terrestrial habitats and consists of crucial functions such as respiration and water balance as well as serving as a defensive barrier due to the secretion of bioactive compounds. We herein report the first investigation on the skin secretion of Odontophrynus americanus, as a potential source of bioactive peptides and also as an indicator of its evolutionary adaptations to changing environments. Americanin-1 was isolated and identified as a neutral peptide exhibiting moderate antibacterial activity against E. coli. Its amphipathic sequence including 19 amino acids and showing a propensity for α-helix structure is discussed. Comparisons of the histomorphology of the skin of O. americanus with other previously documented species within the same genus revealed distinctive features in the Patagonian specimen, differing from conspecifics from other Argentine provinces. The presence of the Eberth-Katschenko layer, a prevalence of iridophores, and the existence of glycoconjugates in its serous glands suggest that the integument is adapted to retain skin moisture. This adaptation is consistent with the prevailing aridity of its native habitat.
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Affiliation(s)
- Natalia L Cancelarich
- Instituto Patagónico para el Estudio de Ecosistemas Continentales (IPEEC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bvd. Brown 2915, Puerto Madryn, Argentina U9120ACD
| | - Miriam Arrulo
- School of Medicine and Population Health, The University of Sheffield, Beech Hill Road, Sheffield S10 2RX, United Kingdom
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | | | - Eder A Barbosa
- Núcleo de Pesquisa em Morfologia e Imunologia Aplicada, NuPMIA, Faculdade de Medicina, Universidade de Brasília, UnB, Brasília, 70910-900, Brazil
- Laboratorio de Síntese e Análise de Biomoléculas, LSAB, Instituto de Química-UnB, Brasília 70910-900, Brazil
| | - Daniel C Moreira
- Núcleo de Pesquisa em Morfologia e Imunologia Aplicada, NuPMIA, Faculdade de Medicina, Universidade de Brasília, UnB, Brasília, 70910-900, Brazil
| | - Néstor G Basso
- Instituto de Diversidad y Evolución Austral (IDEAus), CONICET, Bvd. Brown 2915, Puerto Madryn, Argentina U9120ACD
| | - Luis Orlando Pérez
- Instituto Patagónico de Ciencias Sociales y Humanas (IPCSH), CONICET, Bvd. Brown 2915, Puerto Madryn, Argentina U9120ACD
| | - Cátia Teixeira
- Laboratório Associado para a Química Verde-REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal
- Gyros Protein Technologies, Inc., Tucson, Arizona 85714, United States
| | - Paula Gomes
- Laboratório Associado para a Química Verde-REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal
| | - Beatriz G de la Torre
- Kwazulu-Natal Research Innovation and Sequencing Platform (KRISP), College of Health Sciences, University of KwaZulu-Natal, Durban 4001, South Africa
| | - Fernando Albericio
- School of Chemistry and Physics, University of KwaZulu-Natal, Durban 4001, South Africa
- Networking Centre on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Department of Organic Chemistry, University of Barcelona, 08028 Barcelona, Spain
| | - Peter Eaton
- Bridge, School of Chemistry, University of Lincoln, Lincoln LN6 7EL, United Kingdom
| | - José R S A Leite
- Núcleo de Pesquisa em Morfologia e Imunologia Aplicada, NuPMIA, Faculdade de Medicina, Universidade de Brasília, UnB, Brasília, 70910-900, Brazil
| | - Mariela M Marani
- Instituto Patagónico para el Estudio de Ecosistemas Continentales (IPEEC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bvd. Brown 2915, Puerto Madryn, Argentina U9120ACD
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2
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Weitzman CL, Brown GP, Gibb K, Christian K. Cutaneous shedding in amphibians causes shifts in bacterial microbiomes. Integr Zool 2024. [PMID: 38897983 DOI: 10.1111/1749-4877.12858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Considerable research has focused on microbes on amphibian skin, as they act as the first line of defense against invading pathogens. This effort has generated substantial data on patterns across species, space, time, and ontogeny, alongside a growing list of beneficial antifungal symbionts. Though there is evidence of stability in amphibian skin microbial communities, there is also an indication that regular skin shedding reduces cultivable bacteria, with regrowth and recolonization in the period between sheds. This suggests that skin communities are in constant flux, and we lack an understanding of how the membership and structure of those communities are affected by shedding events. In this study, we conducted experiments on cane toads (Rhinella marina) to investigate the influence of shedding on skin microbiomes. We first used quantitative PCR to verify a positive correlation between bacterial loads and time in the days after shedding. We then resampled individuals over time to describe changes in community composition in the 38 h after shedding using amplicon sequencing. Similar to trends of bacterial loads, we found increases in alpha diversity over time after shedding, suggesting that shedding reduces bacterial diversity as it knocks down bacterial loads. During the 38-h period, community structure became similar to pre-shed communities in some individuals, but there was no consistent pattern in structural changes among individuals. In light of the amphibian chytridiomycosis pandemic, understanding how physiological events such as skin shedding affect beneficial bacteria and communities on amphibians would provide important insight into amphibian ecology.
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Affiliation(s)
- Chava L Weitzman
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina, Northern Territory, Australia
| | - Gregory P Brown
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Karen Gibb
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina, Northern Territory, Australia
| | - Keith Christian
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina, Northern Territory, Australia
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3
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Antony A, Purayil AK, Olakkaran S, Dhannura S, Shekh S, Gowd KH, Gurushankara HP. Antimicrobial and antitumor properties of anuran peptide temporin-SHf induce apoptosis in A549 lung cancer cells. Amino Acids 2024; 56:12. [PMID: 38319435 PMCID: PMC10847208 DOI: 10.1007/s00726-023-03373-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 11/20/2023] [Indexed: 02/07/2024]
Abstract
Temporin-SHf is a linear, ultra-short, hydrophobic, α-helix, and phe-rich cationic antimicrobial peptide. The antitumor activities and mechanism of temporin-SHf-induced cancer cell death are unknown. The temporin-SHf was synthesized by solid-phase Fmoc chemistry and antimicrobial and antitumor activities were investigated. Temporin-SHf was microbiocidal, non-hemolytic, and cytotoxic to human cancer cells but not to non-tumorigenic cells. It affected the cancer cells' lysosomal integrity and caused cell membrane damage. The temporin-SHf inhibited A549 cancer cell proliferation and migration. It is anti-angiogenic and causes cancer cell death through apoptosis. The molecular mechanism of action of temporin-SHf confirmed that it kills cancer cells by triggering caspase-dependent apoptosis through an intrinsic mitochondrial pathway. Owing to its short length and broad spectrum of antitumor activity, temporin-SHf is a promising candidate for developing a new class of anticancer drugs.
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Affiliation(s)
- Anet Antony
- Department of Zoology, School of Biological Sciences, Central University of Kerala, Tejaswini Hills, Periya, Kasaragod, 671 320, India
- Department of Zoology, University of Calicut, Malappuram, Kerala, 673 635, India
| | - Anupama Kizhakke Purayil
- Department of Zoology, School of Biological Sciences, Central University of Kerala, Tejaswini Hills, Periya, Kasaragod, 671 320, India
- Department of Molecular Biology, Kannur University, Dr. Janakiammal Campus, Thalasserry, Palayad, Kerala, 670 661, India
| | - Shilpa Olakkaran
- Department of Zoology, School of Biological Sciences, Central University of Kerala, Tejaswini Hills, Periya, Kasaragod, 671 320, India
- Department of Zoology, University of Calicut, Malappuram, Kerala, 673 635, India
| | - Shweta Dhannura
- Department of Chemistry, School of Chemical Sciences, Central University of Karnataka, Kalaburagi, Karnataka, 585 367, India
| | - Shamasoddin Shekh
- Department of Chemistry, School of Chemical Sciences, Central University of Karnataka, Kalaburagi, Karnataka, 585 367, India
| | - Konkallu Hanumae Gowd
- Department of Chemistry, School of Chemical Sciences, Central University of Karnataka, Kalaburagi, Karnataka, 585 367, India
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4
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Robak MJ, Saenz V, de Cortie E, Richards-Zawacki CL. Effects of temperature on the interaction between amphibian skin bacteria and Batrachochytrium dendrobatidis. Front Microbiol 2023; 14:1253482. [PMID: 37942072 PMCID: PMC10628663 DOI: 10.3389/fmicb.2023.1253482] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 10/06/2023] [Indexed: 11/10/2023] Open
Abstract
Symbiotic relationships between animals and microbes are important for a range of functions, from digestion to protection from pathogens. However, the impact of temperature variation on these animal-microbe interactions remains poorly understood. Amphibians have experienced population declines and even extinctions on a global scale due to chytridiomycosis, a disease caused by chytrid fungi in the genus Batrachochytrium. Variation in susceptibility to this disease exists within and among host species. While the mechanisms generating differences in host susceptibility remain elusive, differences in immune system components, as well as variation in host and environmental temperatures, have been associated with this variation. The symbiotic cutaneous bacteria of amphibians are another potential cause for variation in susceptibility to chytridiomycosis, with some bacterial species producing antifungal metabolites that prevent the growth of Bd. The growth of both Bd and bacteria are affected by temperature, and thus we hypothesized that amphibian skin bacteria may be more effective at preventing Bd growth at certain temperatures. To test this, we collected bacteria from the skins of frogs, harvested the metabolites they produced when grown at three different temperatures, and then grew Bd in the presence of those metabolites under those same three temperatures in a three-by-three fully crossed design. We found that both the temperature at which cutaneous bacteria were grown (and metabolites produced) as well as the temperature at which Bd is grown can impact the ability of cutaneous bacteria to inhibit the growth of Bd. While some bacterial isolates showed the ability to inhibit Bd growth across multiple temperature treatments, no isolate was found to be inhibitive across all combinations of bacterial incubation or Bd challenge temperatures, suggesting that temperature affects both the metabolites produced and the effectiveness of those metabolites against the Bd pathogen. These findings move us closer to a mechanistic understanding of why chytridiomycosis outbreaks and related amphibian declines are often limited to certain climates and seasons.
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Affiliation(s)
- Matthew J. Robak
- Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, United States
| | - Veronica Saenz
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, United States
- Department of Biology, The Pennsylvania State University, State College, PA, United States
| | - Esmee de Cortie
- Falk School of Sustainability and Environment, Chatham University, Pittsburgh, PA, United States
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5
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Woodhams DC, McCartney J, Walke JB, Whetstone R. The adaptive microbiome hypothesis and immune interactions in amphibian mucus. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 145:104690. [PMID: 37001710 PMCID: PMC10249470 DOI: 10.1016/j.dci.2023.104690] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 03/21/2023] [Accepted: 03/22/2023] [Indexed: 05/20/2023]
Abstract
The microbiome is known to provide benefits to hosts, including extension of immune function. Amphibians are a powerful immunological model for examining mucosal defenses because of an accessible epithelial mucosome throughout their developmental trajectory, their responsiveness to experimental treatments, and direct interactions with emerging infectious pathogens. We review amphibian skin mucus components and describe the adaptive microbiome as a novel process of disease resilience where competitive microbial interactions couple with host immune responses to select for functions beneficial to the host. We demonstrate microbiome diversity, specificity of function, and mechanisms for memory characteristic of an adaptive immune response. At a time when industrialization has been linked to losses in microbiota important for host health, applications of microbial therapies such as probiotics may contribute to immunotherapeutics and to conservation efforts for species currently threatened by emerging diseases.
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Affiliation(s)
- Douglas C Woodhams
- Department of Biology, University of Massachusetts Boston, Boston, MA, 02125, USA.
| | - Julia McCartney
- Department of Biology, University of Massachusetts Boston, Boston, MA, 02125, USA
| | - Jenifer B Walke
- Department of Biology, Eastern Washington University, Cheney, WA, 99004-2440, USA
| | - Ross Whetstone
- Department of Biology, University of Massachusetts Boston, Boston, MA, 02125, USA
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6
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Chen B, Zhang Z, Zhang Q, Xu N, Lu T, Wang T, Hong W, Fu Z, Penuelas J, Gillings M, Qian H. Antimicrobial Peptides in the Global Microbiome: Biosynthetic Genes and Resistance Determinants. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:7698-7708. [PMID: 37161271 DOI: 10.1021/acs.est.3c01664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Antimicrobial peptides are a promising new class of antimicrobials that could address the antibiotic resistance crisis, which poses a major threat to human health. These peptides are present in all kingdoms of life, but especially in microorganisms, having multiple origins in diverse taxa. To date, there has been no global study on the diversity of antimicrobial peptides, the hosts in which these occur, and the potential for resistance to these agents. Here, we investigated the diversity and number of antimicrobial peptides in four main habitats (aquatic, terrestrial, human, and engineered) by analyzing 52,515 metagenome-assembled genomes. The number of antimicrobial peptides was higher in the human gut microbiome than in other habitats, and most hosts of antimicrobial peptides were habitat-specific. The relative abundance of genes that confer resistance to antimicrobial peptides varied between habitats and was generally low, except for the built environment and on human skin. The horizontal transfer of potential resistance genes among these habitats was probably constrained by ecological barriers. We systematically quantified the risk of each resistance determinant to human health and found that nearly half of them pose a threat, especially those that confer resistance to multiple AMPs and polymyxin B. Our results help identify the biosynthetic potential of antimicrobial peptides in the global microbiome, further identifying peptides with a low risk of developing resistance.
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Affiliation(s)
- Bingfeng Chen
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, P. R. China
| | - Zhenyan Zhang
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, P. R. China
| | - Qi Zhang
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, P. R. China
| | - Nuohan Xu
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, P. R. China
| | - Tao Lu
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, P. R. China
| | - Tingzhang Wang
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou 310012, P. R. China
| | - Wenjie Hong
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou 310012, P. R. China
| | - Zhengwei Fu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, P. R. China
| | - Josep Penuelas
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Barcelona 08193, Catalonia, Spain
- CREAF, Campus Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona 08193, Catalonia, Spain
| | - Michael Gillings
- ARC Centre of Excellence in Synthetic Biology, Faculty of Science and Engineering, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Haifeng Qian
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, P. R. China
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7
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Rollins-Smith LA. The importance of antimicrobial peptides (AMPs) in amphibian skin defense. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 142:104657. [PMID: 36754220 DOI: 10.1016/j.dci.2023.104657] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 01/20/2023] [Accepted: 02/04/2023] [Indexed: 06/18/2023]
Abstract
Antimicrobial peptides (AMPs) are produced for defense in nearly all taxa from simple bacteria to complex mammalian species. Some amphibian families have developed this defensive strategy to a high level of sophistication by loading the AMPs into specialized granular glands within the dermis. Enervated by the sympathetic nervous system, the granular glands are poised to deliver an array of AMPs to cleanse the wound and facilitate healing. There have been a number of excellent review publications in recent years that describe amphibian AMPs with an emphasis on their possible uses for human medicine. Instead, my aim here is to review what is known about the nature of amphibian AMPs, the diversity of amphibian AMPs, regulation of their production, and to provide the accumulated evidence that they do, indeed, play an important role in the protection of amphibian skin, vital for survival. While much has been learned about amphibian AMPs, there are still important gaps in our understanding of peptide synthesis, storage, and functions.
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Affiliation(s)
- Louise A Rollins-Smith
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA; Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN, USA; Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA.
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Tolpina MD, Vasileva ID, Samgina TY. Modern Approaches in de novo Sequencing of Nontryptic Peptides of Ranid and Hylid Frogs by Means of Mass Spectrometry: A Review. JOURNAL OF ANALYTICAL CHEMISTRY 2022. [DOI: 10.1134/s1061934822130081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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9
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Jeckel AM, Bolton SK, Waters KR, Antoniazzi MM, Jared C, Matsumura K, Nishikawa K, Morimoto Y, Grant T, Saporito RA. Dose-dependent alkaloid sequestration and N-methylation of decahydroquinoline in poison frogs. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2022; 337:537-546. [PMID: 35201668 DOI: 10.1002/jez.2587] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 12/22/2021] [Accepted: 01/27/2022] [Indexed: 06/14/2023]
Abstract
Sequestration of chemical defenses from dietary sources is dependent on the availability of compounds in the environment and the mechanism of sequestration. Previous experiments have shown that sequestration efficiency varies among alkaloids in poison frogs, but little is known about the underlying mechanism. The aim of this study was to quantify the extent to which alkaloid sequestration and modification are dependent on alkaloid availability and/or sequestration mechanism. To do this, we administered different doses of histrionicotoxin (HTX) 235A and decahydroquinoline (DHQ) to captive-bred Adelphobates galactonotus and measured alkaloid quantity in muscle, kidney, liver, and feces. HTX 235A and DHQ were detected in all organs, whereas only DHQ was present in trace amounts in feces. For both liver and skin, the quantity of alkaloid accumulated increased at higher doses for both alkaloids. Accumulation efficiency in the skin increased at higher doses for HTX 235A but remained constant for DHQ. In contrast, the efficiency of HTX 235A accumulation in the liver was inversely related to dose and a similar, albeit statistically nonsignificant, pattern was observed for DHQ. We identified and quantified the N-methylation of DHQ in A. galactonotus, which represents a previously unknown example of alkaloid modification in poison frogs. Our study suggests that variation in alkaloid composition among individuals and species can result from differences in sequestration efficiency related to the type and amount of alkaloids available in the environment.
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Affiliation(s)
- Adriana M Jeckel
- Department of Zoology, Institute of Biosciences, University of São Paulo, São Paulo, São Paulo, Brazil
| | - Sarah K Bolton
- Department of Biology, Notre Dame College, South Euclid, Ohio, USA
| | - Katherine R Waters
- Department of Biology, John Carroll University, University Heights, Ohio, USA
| | - Marta M Antoniazzi
- Structural Biology Lab, Butantan Institute, São Paulo, São Paulo, Brazil
| | - Carlos Jared
- Structural Biology Lab, Butantan Institute, São Paulo, São Paulo, Brazil
| | - Kunihiro Matsumura
- Department of Chemistry, Graduate School of Science, Osaka City University, Osaka, Japan
| | - Keisuke Nishikawa
- Department of Chemistry, Graduate School of Science, Osaka City University, Osaka, Japan
| | - Yoshiki Morimoto
- Department of Chemistry, Graduate School of Science, Osaka City University, Osaka, Japan
| | - Taran Grant
- Department of Zoology, Institute of Biosciences, University of São Paulo, São Paulo, São Paulo, Brazil
| | - Ralph A Saporito
- Department of Biology, John Carroll University, University Heights, Ohio, USA
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10
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Gass J, Voyles J. When Defenses Fail: Atelopus zeteki Skin Secretions Increase Growth of the Pathogen Batrachochytrium dendrobatidis. Integr Comp Biol 2022; 62:1595-1605. [PMID: 35640912 PMCID: PMC9801971 DOI: 10.1093/icb/icac060] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/30/2022] [Accepted: 05/24/2022] [Indexed: 01/05/2023] Open
Abstract
To combat the threat of emerging infectious diseases in wildlife, ecoimmunologists seek to understand the complex interactions among pathogens, their hosts, and their shared environments. The cutaneous fungal pathogen Batrachochytrium dendrobatidis (Bd), has led to the decline of innumerable amphibian species, including the Panamanian golden frog (Atelopus zeteki). Given that Bd can evade or dampen the acquired immune responses of some amphibians, nonspecific immune defenses are thought to be especially important for amphibian defenses against Bd. In particular, skin secretions constitute a vital component of amphibian innate immunity against skin infections, but their role in protecting A. zeteki from Bd is unknown. We investigated the importance of this innate immune component by reducing the skin secretions from A. zeteki and evaluating their effectiveness against Bd in vitro and in vivo. Following exposure to Bd in a controlled inoculation experiment, we compared key disease characteristics (e.g., changes in body condition, prevalence, pathogen loads, and survival) among groups of frogs that had their skin secretions reduced and control frogs that maintained their skin secretions. Surprisingly, we found that the skin secretions collected from A. zeteki increased Bd growth in vitro. This finding was further supported by infection and survival patterns in the in vivo experiment where frogs with reduced skin secretions tended to have lower pathogen loads and survive longer compared to frogs that maintained their secretions. These results suggest that the skin secretions of A. zeteki are not only ineffective at inhibiting Bd but may enhance Bd growth, possibly leading to greater severity of disease and higher mortality in this highly vulnerable species. These results differ from those of previous studies in other amphibian host species that suggest that skin secretions are a key defense in protecting amphibians from developing severe chytridiomycosis. Therefore, we suggest that the importance of immune components cannot be generalized across all amphibian species or over time. Moreover, the finding that skin secretions may be enhancing Bd growth emphasizes the importance of investigating these immune components in detail, especially for species that are a conservation priority.
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Affiliation(s)
- Jordan Gass
- Department of Biology, University of Nevada at Reno, 1664 North Virginia Street, Reno, NV 89557, USA
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11
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Firneno TJ, Ramesh B, Maldonado JA, Hernandez-Briones AI, Emery AH, Roelke CE, Fujita MK. Transcriptomic analysis reveals potential candidate pathways and genes involved in toxin biosynthesis in true toads. J Hered 2022; 113:311-324. [PMID: 35325156 DOI: 10.1093/jhered/esac015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 03/21/2022] [Indexed: 11/13/2022] Open
Abstract
Synthesized chemical defenses have broadly evolved across countless taxa and are important in shaping evolutionary and ecological interactions within ecosystems. However, the underlying genomic mechanisms by which these organisms synthesize and utilize their toxins are relatively unknown. Herein, we use comparative transcriptomics to uncover potential toxin synthesizing genes and pathways, as well as interspecific patterns of toxin synthesizing genes across ten species of North American true toads (Bufonidae). Upon assembly and annotation of the ten transcriptomes, we explored patterns of relative gene expression and possible protein-protein interactions across the species to determine what genes and/or pathways may be responsible for toxin synthesis. We also tested our transcriptome dataset for signatures of positive selection to reveal how selection may be acting upon potential toxin producing genes. We assembled high quality transcriptomes of the bufonid parotoid gland, a tissue not often investigated in other bufonid related RNAseq studies. We found several genes involved in metabolic and biosynthetic pathways (e.g. steroid biosynthesis, terpenoid backbone biosynthesis, isoquinoline biosynthesis, glucosinolate biosynthesis) that were functionally enriched and/or relatively expressed across the ten focal species that may be involved in the synthesis of alkaloid and steroid toxins, as well as other small metabolic compounds that cause distastefulness in bufonids. We hope that our study lays a foundation for future studies to explore the genomic underpinnings and specific pathways of toxin synthesis in toads, as well as at the macroevolutionary scale across numerous taxa that produce their own defensive toxins.
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Affiliation(s)
- Thomas J Firneno
- Department of Biology, University of Texas, Arlington, Texas, 76019-0498, USA.,Amphibian and Reptile Diversity Research Center, Department of Biology, University of Texas, Arlington, Texas, 76019-0498, USA
| | - Balan Ramesh
- Department of Biology, University of Texas, Arlington, Texas, 76019-0498, USA
| | - Jose A Maldonado
- Department of Biology, University of Texas, Arlington, Texas, 76019-0498, USA.,Amphibian and Reptile Diversity Research Center, Department of Biology, University of Texas, Arlington, Texas, 76019-0498, USA
| | | | - Alyson H Emery
- Department of Biology, University of Texas, Arlington, Texas, 76019-0498, USA
| | - Corey E Roelke
- Department of Biology, University of Texas, Arlington, Texas, 76019-0498, USA.,Amphibian and Reptile Diversity Research Center, Department of Biology, University of Texas, Arlington, Texas, 76019-0498, USA
| | - Matthew K Fujita
- Department of Biology, University of Texas, Arlington, Texas, 76019-0498, USA.,Amphibian and Reptile Diversity Research Center, Department of Biology, University of Texas, Arlington, Texas, 76019-0498, USA
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12
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Ujszegi J, Ludányi K, Móricz ÁM, Krüzselyi D, Drahos L, Drexler T, Németh MZ, Vörös J, Garner TWJ, Hettyey A. Exposure to Batrachochytrium dendrobatidis affects chemical defences in two anuran amphibians, Rana dalmatina and Bufo bufo. BMC Ecol Evol 2021; 21:135. [PMID: 34217227 PMCID: PMC8254444 DOI: 10.1186/s12862-021-01867-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 06/23/2021] [Indexed: 11/03/2022] Open
Abstract
Background Batrachochytrium dendrobatidis (Bd) is the causative agent of chytridiomycosis, one of the major causes of worldwide amphibian biodiversity loss. Many amphibians exhibit skin-based chemical defences, which may play an important role against invading pathogens, but whether the synthesis of these chemical compounds is enhanced or suppressed in the presence of pathogens is largely unknown. Here we investigated direct and indirect effects of larval exposure to the globally distributed and highly virulent Bd-GPL strain on skin secreted chemical defences and life history traits during early ontogeny of agile frogs (Rana dalmatina) and common toads (Bufo bufo). Results Exposure to Bd during the larval stage did not result in enhanced synthesis of the antimicrobial peptide Brevinin-1 Da in R. dalmatina tadpoles or in increased production of bufadienolides in B. bufo tadpoles. However, exposure to Bd during the larval stage had a carry-over effect reaching beyond metamorphosis: both R. dalmatina and B. bufo froglets contained smaller quantities of defensive chemicals than their Bd-naïve conspecifics in the control treatment. Prevalence of Bd and infection intensities were very low in both larvae and metamorphs of R. dalmatina, while in B. bufo we observed high Bd prevalence and infection intensities, especially in metamorphs. At the same time, we did not find a significant effect of Bd-exposure on body mass or development rate in larvae or metamorphs in either species. Conclusions The lack of detrimental effect of Bd-exposure on life history traits, even parallel with high infection intensities in the case of B. bufo individuals, is surprising and suggests high tolerance of local populations of these two species against Bd. However, the lowered quantity of defensive chemicals may compromise antimicrobial and antipredatory defences of froglets, which may ultimately contribute to population declines also in the absence of conspicuous mass-mortality events.
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Affiliation(s)
- János Ujszegi
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Herman Ottó út 15, Budapest, 1022, Hungary.
| | - Krisztina Ludányi
- Department of Pharmaceutics, Faculty of Pharmacy, Semmelweis University, Hőgyes Endre utca 7, Budapest, 1092, Hungary
| | - Ágnes M Móricz
- Department of Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, Herman Ottó út 15, Budapest, 1022, Hungary
| | - Dániel Krüzselyi
- Department of Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, Herman Ottó út 15, Budapest, 1022, Hungary
| | - László Drahos
- MS Proteomics Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Magyar tudósok körútja 2, Budapest, 1117, Hungary
| | - Tamás Drexler
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Herman Ottó út 15, Budapest, 1022, Hungary.,Department of Ecology, Institute for Biology, University of Veterinary Medicine, Rottenbiller utca 50, Budapest, 1077, Hungary
| | - Márk Z Németh
- Department of Plant Pathology, Plant Protection Institute, Centre for Agricultural Research, Herman Ottó út 15, Budapest, 1022, Hungary
| | - Judit Vörös
- Department of Zoology, Hungarian Natural History Museum, Baross street 13, Budapest, 1088, Hungary
| | - Trenton W J Garner
- Institute of Zoology, Zoological Society of London, Regent's Park, London, NW1 4RY, UK.,Unit for Environmental Sciences and Management, North-West University, Potchefstroom, 2520, South Africa
| | - Attila Hettyey
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Herman Ottó út 15, Budapest, 1022, Hungary.,Department of Ecology, Institute for Biology, University of Veterinary Medicine, Rottenbiller utca 50, Budapest, 1077, Hungary
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13
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Herczeg D, Ujszegi J, Kásler A, Holly D, Hettyey A. Host-multiparasite interactions in amphibians: a review. Parasit Vectors 2021; 14:296. [PMID: 34082796 PMCID: PMC8173923 DOI: 10.1186/s13071-021-04796-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 05/20/2021] [Indexed: 01/15/2023] Open
Abstract
Parasites, including viruses, bacteria, fungi, protists, helminths, and arthropods, are ubiquitous in the animal kingdom. Consequently, hosts are frequently infected with more than one parasite species simultaneously. The assessment of such co-infections is of fundamental importance for disease ecology, but relevant studies involving non-domesticated animals have remained scarce. Many amphibians are in decline, and they generally have a highly diverse parasitic fauna. Here we review the literature reporting on field surveys, veterinary case studies, and laboratory experiments on co-infections in amphibians, and we summarize what is known about within-host interactions among parasites, which environmental and intrinsic factors influence the outcomes of these interactions, and what effects co-infections have on hosts. The available literature is piecemeal, and patterns are highly diverse, so that identifying general trends that would fit most host–multiparasite systems in amphibians is difficult. Several examples of additive, antagonistic, neutral, and synergistic effects among different parasites are known, but whether members of some higher taxa usually outcompete and override the effects of others remains unclear. The arrival order of different parasites and the time lag between exposures appear in many cases to fundamentally shape competition and disease progression. The first parasite to arrive can gain a marked reproductive advantage or induce cross-reaction immunity, but by disrupting the skin and associated defences (i.e., skin secretions, skin microbiome) and by immunosuppression, it can also pave the way for subsequent infections. Although there are exceptions, detrimental effects to the host are generally aggravated with increasing numbers of co-infecting parasite species. Finally, because amphibians are ectothermic animals, temperature appears to be the most critical environmental factor that affects co-infections, partly via its influence on amphibian immune function, partly due to its direct effect on the survival and growth of parasites. Besides their importance for our understanding of ecological patterns and processes, detailed knowledge about co-infections is also crucial for the design and implementation of effective wildlife disease management, so that studies concentrating on the identified gaps in our understanding represent rewarding research avenues. ![]()
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Affiliation(s)
- Dávid Herczeg
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, Budapest, 1022, Hungary.
| | - János Ujszegi
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, Budapest, 1022, Hungary
| | - Andrea Kásler
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, Budapest, 1022, Hungary.,Department of Systematic Zoology and Ecology, Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest, 1117, Hungary
| | - Dóra Holly
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, Budapest, 1022, Hungary.,Department of Systematic Zoology and Ecology, Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest, 1117, Hungary
| | - Attila Hettyey
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, Budapest, 1022, Hungary.,Department of Ecology, Institute for Biology, University of Veterinary Medicine, Rottenbiller utca 50, Budapest, 1077, Hungary
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14
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Barran G, Kolodziejek J, Coquet L, Leprince J, Jouenne T, Nowotny N, Conlon JM, Mechkarska M. Peptidomic Analysis of Skin Secretions of the Caribbean Frogs Leptodactylus insularum and Leptodactylus nesiotus (Leptodactylidae) Identifies an Ocellatin with Broad Spectrum Antimicrobial Activity. Antibiotics (Basel) 2020; 9:antibiotics9100718. [PMID: 33092132 PMCID: PMC7588904 DOI: 10.3390/antibiotics9100718] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 09/27/2020] [Accepted: 10/19/2020] [Indexed: 11/23/2022] Open
Abstract
Ocellatins are peptides produced in the skins of frogs belonging to the genus Leptodactylus that generally display weak antimicrobial activity against Gram-negative bacteria only. Peptidomic analysis of norepinephrine-stimulated skin secretions from Leptodactylus insularum Barbour 1906 and Leptodactylus nesiotus Heyer 1994, collected in the Icacos Peninsula, Trinidad, led to the purification and structural characterization of five ocellatin-related peptides from L. insularum (ocellatin-1I together with its (1–16) fragment, ocellatin-2I and its (1–16) fragment, and ocellatin-3I) and four ocellatins from L. nesiotus (ocellatin-1N, -2N, -3N, and -4N). While ocellatins-1I, -2I, and -1N showed a typically low antimicrobial potency against Gram-negative bacteria, ocellatin-3N (GIFDVLKNLAKGVITSLAS.NH2) was active against an antibiotic-resistant strain of Klebsiella pneumoniae and reference strains of Escherichia coli, K. pneumoniae, Pseudomonas aeruginosa, and Salmonella typhimurium (minimum inhibitory concentrations (MICs) in the range 31.25–62.5 μM), and was the only peptide active against Gram-positive Staphylococcus aureus (MIC = 31.25 μM) and Enterococcus faecium (MIC = 62.5 μM). The therapeutic potential of ocellatin-3N is limited by its moderate hemolytic activity (LC50 = 98 μM) against mouse erythrocytes. The peptide represents a template for the design of long-acting, non-toxic, and broad-spectrum antimicrobial agents for targeting multidrug-resistant pathogens.
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Affiliation(s)
- Gervonne Barran
- Department of Life Sciences, Faculty of Science and Technology, The University of The West Indies, St. Augustine Campus, Trinidad and Tobago;
| | - Jolanta Kolodziejek
- Viral Zoonoses, Emerging and Vector-Borne Infections Group, Department of Pathobiology, Institute of Virology, University of Veterinary Medicine, Veterinärplatz 1, A-1210 Vienna, Austria; (J.K.); (N.N.)
| | - Laurent Coquet
- CNRS UMR 6270, PISSARO, Institute for Research and Innovation in Biomedicine (IRIB), Normandy University, 76000 Rouen, France; (L.C.); (T.J.)
| | - Jérôme Leprince
- Inserm U1239, PRIMACEN, Institute for Research and Innovation in Biomedicine (IRIB), Normandy University, 76000 Rouen, France;
| | - Thierry Jouenne
- CNRS UMR 6270, PISSARO, Institute for Research and Innovation in Biomedicine (IRIB), Normandy University, 76000 Rouen, France; (L.C.); (T.J.)
| | - Norbert Nowotny
- Viral Zoonoses, Emerging and Vector-Borne Infections Group, Department of Pathobiology, Institute of Virology, University of Veterinary Medicine, Veterinärplatz 1, A-1210 Vienna, Austria; (J.K.); (N.N.)
- Department of Basic Medical Sciences, College of Medicine, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai Helathcare City, P.O. Box 505055, Dubai, UAE
| | - J. Michael Conlon
- Diabetes Research Group, School of Biomedical Sciences, University of Ulster, Coleraine BT52 1SA, Northern Ireland, UK
- Correspondence: (J.M.C.); (M.M.)
| | - Milena Mechkarska
- Department of Life Sciences, Faculty of Science and Technology, The University of The West Indies, St. Augustine Campus, Trinidad and Tobago;
- Correspondence: (J.M.C.); (M.M.)
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15
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Gaiser RA, Ayerra Mangado J, Mechkarska M, Kaman WE, van Baarlen P, Conlon JM, Wells JM. Selection of antimicrobial frog peptides and temporin-1DRa analogues for treatment of bacterial infections based on their cytotoxicity and differential activity against pathogens. Chem Biol Drug Des 2020; 96:1103-1113. [PMID: 31102497 PMCID: PMC7891380 DOI: 10.1111/cbdd.13569] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 04/27/2019] [Accepted: 05/05/2019] [Indexed: 01/02/2023]
Abstract
Cationic, amphipathic, α-helical host-defense peptides (HDPs) that are naturally secreted by certain species of frogs (Anura) possess potent broad-spectrum antimicrobial activity and show therapeutic potential as alternatives to treat infections by multidrug-resistant pathogens. Fourteen amphibian skin peptides and twelve analogues of temporin-1DRa were studied for their antimicrobial activities against clinically relevant human or animal skin infection-associated pathogens. For comparison, antimicrobial potencies of frog skin peptides against a range of probiotic lactobacilli were determined. We used the VITEK 2 system to define a profile of antibiotic susceptibility for the bacterial panel. The minimal inhibitory concentration (MIC) values of the naturally occurring temporin-1DRa, CPF-AM1, alyteserin-1c, hymenochirin-2B, and hymenochirin-4B for pathogenic bacteria were threefold to ninefold lower than the values for the tested probiotic strains. Similarly, temporin-1DRa and its [Lys4 ], [Lys5 ], and [Aib8 ] analogues showed fivefold to 6.5-fold greater potency against the pathogens. In the case of PGLa-AM1, XT-7, temporin-1DRa and its [D-Lys8 ] and [Aib13 ] analogues, no apoptosis or necrosis was detected in human peripheral blood mononuclear cells at concentrations below or above the MIC. Given the differential activity against commensal bacteria and pathogens, some of these peptides are promising candidates for further development into therapeutics for topical treatment of skin infections.
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Affiliation(s)
- Rogier A Gaiser
- Host-Microbe Interactomics Group, Animal Sciences Department, Wageningen University, Wageningen, The Netherlands
| | - Jaione Ayerra Mangado
- Host-Microbe Interactomics Group, Animal Sciences Department, Wageningen University, Wageningen, The Netherlands
| | - Milena Mechkarska
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Wendy E Kaman
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Centre Rotterdam (EMC), Rotterdam, The Netherlands
| | - Peter van Baarlen
- Host-Microbe Interactomics Group, Animal Sciences Department, Wageningen University, Wageningen, The Netherlands
| | - J Michael Conlon
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Jerry M Wells
- Host-Microbe Interactomics Group, Animal Sciences Department, Wageningen University, Wageningen, The Netherlands
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16
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A Novel Antimicrobial Peptide (Kassinatuerin-3) Isolated from the Skin Secretion of the African Frog, Kassina senegalensis. BIOLOGY 2020; 9:biology9070148. [PMID: 32630734 PMCID: PMC7408539 DOI: 10.3390/biology9070148] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 06/21/2020] [Accepted: 06/24/2020] [Indexed: 01/05/2023]
Abstract
Amphibian skin secretions are remarkable sources of novel bioactive peptides. Among these, antimicrobial peptides have demonstrated an outstanding efficacy in killing microorganisms via a general membranolytic mechanism, which may offer the prospect of solving specific target-driven antibiotic resistance. Here, the discovery of a novel defensive peptide is described from the skin secretion of the African frog, Kassina senegalensis. Named kassinatuerin-3, it was identified through a combination of “shot-gun” cloning and MS/MS fragmentation sequencing. Subsequently, a synthetic replicate was subjected to biofunctional evaluation. The results indicated that kassinatuerin-3 possessed antimicrobial activity against Gram-positive bacteria but no effect against Gram-negative bacteria. Additionally, it was active in biofilm eradication on S. aureus and MRSA and in the antiproliferation of selected cancer cell lines. Moreover, it had a very mild hemolytic effect, which demonstrated a high therapeutic index for kassinatuerin-3. Collectively, although kassinatuerin-3 did not demonstrate remarkable bioactivities compared with other natural or synthetic antimicrobial peptides (AMPs), it offered a new insight into the design of antimicrobial derivatives.
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17
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Rebollar EA, Martínez-Ugalde E, Orta AH. The Amphibian Skin Microbiome and Its Protective Role Against Chytridiomycosis. HERPETOLOGICA 2020. [DOI: 10.1655/0018-0831-76.2.167] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Eria A. Rebollar
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, México
| | - Emanuel Martínez-Ugalde
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, México
| | - Alberto H. Orta
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, México
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18
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Ujszegi J, Vajna B, Móricz ÁM, Krüzselyi D, Korponai K, Krett G, Hettyey A. Relationships Between Chemical Defenses of Common Toad (Bufo bufo) Tadpoles and Bacterial Community Structure of their Natural Aquatic Habitat. J Chem Ecol 2020; 46:534-543. [PMID: 32468489 PMCID: PMC7332479 DOI: 10.1007/s10886-020-01184-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 03/10/2020] [Accepted: 05/15/2020] [Indexed: 12/02/2022]
Abstract
Many organisms synthesize secondary metabolites against natural enemies. However, to which environmental factors the production of these metabolites is adjusted to is poorly investigated in animals, especially so in vertebrates. Bufadienolides are steroidal compounds that are present in a wide range of plants and animals and, if present in large quantities, can provide protection against natural enemies, such as pathogens. In a correlative study involving 16 natural populations we investigated how variation in bufadienolide content of larval common toads (Bufo bufo) is associated with the bacterial community structure of their aquatic environment. We also evaluated pond size, macrovegetation cover, and the abundance of predators, conspecifics and other larval amphibians. We measured toxin content of tadpoles using HPLC-MS and determined the number of bufadienolide compounds (NBC) and the total quantity of bufadienolides (TBQ). AICc-based model selection revealed strong relationships of NBC and TBQ with bacterial community structure of the aquatic habitat as well as with the presence of conspecific tadpoles. The observed relationships may have arisen due to adaptation to local bacterial communities, phenotypic plasticity, differential biotransformation of toxin compounds by different bacterial communities, or a combination of these processes. Bacterial groups that contribute to among-population variation in toxin content remain to be pinpointed, but our study suggesting that toxin production may be influenced by the bacterial community of the environment represents an important step towards understanding the ecological and evolutionary processes leading to microbiota-mediated variation in skin toxin profiles of aquatic vertebrates.
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Affiliation(s)
- János Ujszegi
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Herman Ottó út 15, Budapest, 1022, Hungary.
| | - Balázs Vajna
- Department of Microbiology, Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest, 1117, Hungary
| | - Ágnes M Móricz
- Department of Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, Herman Ottó út 15, Budapest, 1022, Hungary
| | - Dániel Krüzselyi
- Department of Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, Herman Ottó út 15, Budapest, 1022, Hungary
| | - Kristóf Korponai
- Department of Microbiology, Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest, 1117, Hungary
| | - Gergely Krett
- Department of Microbiology, Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest, 1117, Hungary
- Danube Research Institute, Centre for Ecological Research, Karolina út 29, Budapest, 1113, Hungary
| | - Attila Hettyey
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Herman Ottó út 15, Budapest, 1022, Hungary
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19
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Yin Z, Sun K, Li A, Sun D, Li Z, Xiao G, Feng J. Changes in the gut microbiota during Asian particolored bat ( Vespertilio sinensis) development. PeerJ 2020; 8:e9003. [PMID: 32435532 PMCID: PMC7227643 DOI: 10.7717/peerj.9003] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 03/26/2020] [Indexed: 12/26/2022] Open
Abstract
Background The gut microbiota is closely linked to host development, diet and health and is influenced by both the host and the environment. Although many studies have focused on the dynamics of the gut microbiota during development in captive animals, few studies have focused on the dynamics of the gut microbiota during development in wild animals, especially for the order Chiroptera. Methods In this study, we characterized the gut microbiota of the wild Asian particolored bat (Vespertilio sinensis) from 1 day to 6 weeks after birth. We explored the changes in their gut microbial community compositions, examined possible influencing factors, and predicted the feeding transition period. Results The gut microbiota changed during the development of V. sinensis. The alpha diversity of the bats' gut microbiota gradually increased but did not change significantly from the 1st day to the 4th week after birth; however, the alpha diversity decreased significantly in week 5, then stabilized. The beta diversity differed slightly in weeks 4-6. In week 4, the fecal samples showed the highest diversity in bacterial community composition. Thus, we predicted that the potential feeding transition period for V. sinensis may occur during week 4. Redundancy analysis showed that age and body mass index significantly affected the compositional changes of the gut microbiota in Asian particolored bats. Conclusion The gut microbiota changed during the development of V. sinensis. We suggest that changes in the alpha and beta diversity during week 4 after birth indicate a potential feeding transition, highlighting the importance of diet in the gut microbiota during the development of V. sinensis.
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Affiliation(s)
- Zhongwei Yin
- College of Life Science, Jilin Agricultural University, Changchun, China.,Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, China
| | - Keping Sun
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, China
| | - Aoqiang Li
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, China
| | - Deyi Sun
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, China
| | - Zhongle Li
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, China.,College of Animal Science and Technology, Jilin Agricultural University, Changchun, China
| | - Guohong Xiao
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, China
| | - Jiang Feng
- College of Life Science, Jilin Agricultural University, Changchun, China.,Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, China
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20
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Casciaro B, Cappiello F, Loffredo MR, Ghirga F, Mangoni ML. The Potential of Frog Skin Peptides for Anti-Infective Therapies: The Case of Esculentin-1a(1-21)NH2. Curr Med Chem 2020; 27:1405-1419. [PMID: 31333082 DOI: 10.2174/0929867326666190722095408] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 06/25/2019] [Accepted: 07/16/2019] [Indexed: 12/26/2022]
Abstract
Antimicrobial Peptides (AMPs) are the key effectors of the innate immunity and represent promising molecules for the development of new antibacterial drugs. However, to achieve this goal, some problems need to be overcome: (i) the cytotoxic effects at high concentrations; (ii) the poor biostability and (iii) the difficulty in reaching the target site. Frog skin is one of the richest natural storehouses of AMPs, and over the years, many peptides have been isolated from it, characterized and classified into several families encompassing temporins, brevinins, nigrocins and esculentins. In this review, we summarized how the isolation/characterization of peptides belonging to the esculentin-1 family drove us to the design of an analogue, i.e. esculentin-1a(1-21)NH2, with a powerful antimicrobial action and immunomodulatory properties. The peptide had a wide spectrum of activity, especially against the opportunistic Gram-negative bacterium Pseudomonas aeruginosa. We described the structural features and the in vitro/in vivo biological characterization of this peptide as well as the strategies used to improve its biological properties. Among them: (i) the design of a diastereomer carrying Damino acids in order to reduce the peptide's cytotoxicity and improve its half-life; (ii) the covalent conjugation of the peptide to gold nanoparticles or its encapsulation into poly(lactide- co-glycolide) nanoparticles; and (iii) the peptide immobilization to biomedical devices (such as silicon hydrogel contact lenses) to obtain an antibacterial surface able to reduce microbial growth and attachment. Summing up the best results obtained so far, this review traces all the steps that led these frog-skin AMPs to the direction of peptide-based drugs for clinical use.
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Affiliation(s)
- Bruno Casciaro
- Laboratory affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy.,Center for Life Nano Science@ Sapienza, Istituto Italiano di Tecnologia, Viale Regina Elena 291, 00161 Rome, Italy
| | - Floriana Cappiello
- Laboratory affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Maria Rosa Loffredo
- Laboratory affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Francesca Ghirga
- Center for Life Nano Science@ Sapienza, Istituto Italiano di Tecnologia, Viale Regina Elena 291, 00161 Rome, Italy
| | - Maria Luisa Mangoni
- Laboratory affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
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21
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Raaymakers C, Stijlemans B, Martin C, Zaman S, Ballet S, Martel A, Pasmans F, Roelants K. A New Family of Diverse Skin Peptides from the Microhylid Frog Genus Phrynomantis. Molecules 2020; 25:E912. [PMID: 32085597 PMCID: PMC7070584 DOI: 10.3390/molecules25040912] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/12/2020] [Accepted: 02/18/2020] [Indexed: 01/10/2023] Open
Abstract
A wide range of frogs produce skin poisons composed of bioactive peptides for defence against pathogens, parasites and predators. While several frog families have been thoroughly screened for skin-secreted peptides, others, like the Microhylidae, have remained mostly unexplored. Previous studies of microhylids found no evidence of peptide secretion, suggesting that this defence adaptation was evolutionarily lost. We conducted transcriptome analyses of the skins of Phrynomantis bifasciatus and Phrynomantis microps, two African microhylid species long suspected to be poisonous. Our analyses reveal 17 evolutionary related transcripts that diversified from to those of cytolytic peptides found in other frog families. The 19 peptides predicted to be processed from these transcripts, named phrynomantins, show a striking structural diversity that is distinct from any previously identified frog skin peptide. Functional analyses of five phrynomantins confirm the loss of a cytolytic function and the absence of insecticidal or proinflammatory activity, suggesting that they represent an evolutionary transition to a new, yet unknown function. Our study shows that peptides have been retained in the defence poison of at least one microhylid lineage and encourages research on similarly understudied taxa to further elucidate the diversity and evolution of skin defence molecules.
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Affiliation(s)
- Constantijn Raaymakers
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Elsene, Belgium; (C.R.); (S.Z.)
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium; (A.M.); (F.P.)
| | - Benoit Stijlemans
- Unit of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Elsene, Belgium;
- Myeloid Cell Immunology Lab, VIB Centre for Inflammation Research, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Elsene, Belgium
| | - Charlotte Martin
- Research Group of Organic Chemistry, Department of Chemistry and Department of Bio-engineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Elsene, Belgium; (C.M.); (S.B.)
| | - Shabnam Zaman
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Elsene, Belgium; (C.R.); (S.Z.)
| | - Steven Ballet
- Research Group of Organic Chemistry, Department of Chemistry and Department of Bio-engineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Elsene, Belgium; (C.M.); (S.B.)
| | - An Martel
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium; (A.M.); (F.P.)
| | - Frank Pasmans
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium; (A.M.); (F.P.)
| | - Kim Roelants
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Elsene, Belgium; (C.R.); (S.Z.)
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Wang Q, Xia R, Ji JJ, Zhu Q, Li XP, Ma Y, Xu YC. Diversity of Antimicrobial Peptides in Three Partially Sympatric Frog Species in Northeast Asia and Implications for Evolution. Genes (Basel) 2020; 11:E158. [PMID: 32024145 PMCID: PMC7073735 DOI: 10.3390/genes11020158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 01/27/2020] [Accepted: 01/30/2020] [Indexed: 01/31/2023] Open
Abstract
Antimicrobial peptides (AMPs) are evolutionarily ancient molecules that play an essential role in innate immunity across taxa from invertebrates to vertebrates. The evolution system of AMP system has not been well explained in the literature. In this study, we cloned and sequenced AMP transcriptomes of three frog species, namely Rana dybowskii, Rana amurensis, and Pelophylax nigromaculatus, which are partially sympatric in northeast Asia, but show different habitat preferences. We found that each species contained 7 to 14 families of AMPs and the diversity was higher in species with a large geographic range and greater habitat variation. All AMPs are phylogenetically related but not associated with the speciation process. Most AMP genes were under negative selection. We propose that the diversification and addition of novel functions and improvement of antimicrobial efficiency are facilitated by the expansion of family members and numbers. We also documented significant negative correlation of net charges and numbers of amino acid residues between the propiece and mature peptide segments. This supports the Net Charge Balance Hypothesis. We propose the Cut Point Sliding Hypothesis as a novel diversification mechanism to explain the correlation in lengths of the two segments.
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Affiliation(s)
- Qing Wang
- Department of Physiology, College of Wildlife and Protected Area, Northeast Forestry University, Harbin 150040, China; (Q.W.); (R.X.); (J.J.J.); (Q.Z.); (X.P.L.); (Y.M.)
| | - Rui Xia
- Department of Physiology, College of Wildlife and Protected Area, Northeast Forestry University, Harbin 150040, China; (Q.W.); (R.X.); (J.J.J.); (Q.Z.); (X.P.L.); (Y.M.)
- Department of Ecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jing Jing Ji
- Department of Physiology, College of Wildlife and Protected Area, Northeast Forestry University, Harbin 150040, China; (Q.W.); (R.X.); (J.J.J.); (Q.Z.); (X.P.L.); (Y.M.)
- BGI-Shenzhen, Shenzhen 518083, China
| | - Qian Zhu
- Department of Physiology, College of Wildlife and Protected Area, Northeast Forestry University, Harbin 150040, China; (Q.W.); (R.X.); (J.J.J.); (Q.Z.); (X.P.L.); (Y.M.)
- Beijing E-young Technology Company Limited, Beijing 100021, China
| | - Xiao Ping Li
- Department of Physiology, College of Wildlife and Protected Area, Northeast Forestry University, Harbin 150040, China; (Q.W.); (R.X.); (J.J.J.); (Q.Z.); (X.P.L.); (Y.M.)
- BGI-Shenzhen, Shenzhen 518083, China
| | - Yue Ma
- Department of Physiology, College of Wildlife and Protected Area, Northeast Forestry University, Harbin 150040, China; (Q.W.); (R.X.); (J.J.J.); (Q.Z.); (X.P.L.); (Y.M.)
- State Forestry and Grassland Administration Detecting Centre of Wildlife, Harbin 150040, China
| | - Yan Chun Xu
- Department of Physiology, College of Wildlife and Protected Area, Northeast Forestry University, Harbin 150040, China; (Q.W.); (R.X.); (J.J.J.); (Q.Z.); (X.P.L.); (Y.M.)
- State Forestry and Grassland Administration Detecting Centre of Wildlife, Harbin 150040, China
- State Forestry and Grassland Administration Research Center of Engineering Technology for Wildlife Conservation and Utilization, Harbin 150040, China
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Woodhams DC, Rollins-Smith LA, Reinert LK, Lam BA, Harris RN, Briggs CJ, Vredenburg VT, Patel BT, Caprioli RM, Chaurand P, Hunziker P, Bigler L. Probiotics Modulate a Novel Amphibian Skin Defense Peptide That Is Antifungal and Facilitates Growth of Antifungal Bacteria. MICROBIAL ECOLOGY 2020; 79:192-202. [PMID: 31093727 DOI: 10.1007/s00248-019-01385-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 04/25/2019] [Indexed: 06/09/2023]
Abstract
Probiotics can ameliorate diseases of humans and wildlife, but the mechanisms remain unclear. Host responses to interventions that change their microbiota are largely uncharacterized. We applied a consortium of four natural antifungal bacteria to the skin of endangered Sierra Nevada yellow-legged frogs, Rana sierrae, before experimental exposure to the pathogenic fungus Batrachochytrium dendrobatidis (Bd). The probiotic microbes did not persist, nor did they protect hosts, and skin peptide sampling indicated immune modulation. We characterized a novel skin defense peptide brevinin-1Ma (FLPILAGLAANLVPKLICSITKKC) that was downregulated by the probiotic treatment. Brevinin-1Ma was tested against a range of amphibian skin cultures and found to inhibit growth of fungal pathogens Bd and B. salamandrivorans, but enhanced the growth of probiotic bacteria including Janthinobacterium lividum, Chryseobacterium ureilyticum, Serratia grimesii, and Pseudomonas sp. While commonly thought of as antimicrobial peptides, here brevinin-1Ma showed promicrobial function, facilitating microbial growth. Thus, skin exposure to probiotic bacterial cultures induced a shift in skin defense peptide profiles that appeared to act as an immune response functioning to regulate the microbiome. In addition to direct microbial antagonism, probiotic-host interactions may be a critical mechanism affecting disease resistance.
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Affiliation(s)
- Douglas C Woodhams
- Department of Biology, University of Massachusetts Boston, Boston, MA, 02125, USA.
| | - Louise A Rollins-Smith
- Departments of Pathology, Microbiology and Immunology and Pediatrics, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
- Department of Biological Science, Vanderbilt University School of Medicine, Nashville, TN, 37235, USA
| | - Laura K Reinert
- Departments of Pathology, Microbiology and Immunology and Pediatrics, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Briana A Lam
- Department of Biology, James Madison University, Harrisonburg, VA, 22807, USA
| | - Reid N Harris
- Department of Biology, James Madison University, Harrisonburg, VA, 22807, USA
| | - Cheryl J Briggs
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, 93106-9610, USA
| | - Vance T Vredenburg
- Department of Biology, San Francisco State University, San Francisco, CA, 94132-1722, USA
| | - Bhumi T Patel
- Department of Biology, University of Massachusetts Boston, Boston, MA, 02125, USA
| | - Richard M Caprioli
- Mass Spectrometry Research Center and Department of Biochemistry, Vanderbilt University, Nashville, TN, 37232-8575, USA
| | - Pierre Chaurand
- Department of Chemistry, Université de Montréal, Montreal, QC, H3T 1J4, Canada
| | - Peter Hunziker
- Functional Genomics Center Zurich, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Laurent Bigler
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
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24
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Chen D, Zhou X, Chen X, Huang L, Xi X, Ma C, Zhou M, Wang L, Chen T. Evaluating the Bioactivity of a Novel Antimicrobial and Anticancer Peptide, Dermaseptin-PS4(Der-PS4), from the Skin Secretion of Phyllomedusa sauvagii. Molecules 2019; 24:molecules24162974. [PMID: 31426323 PMCID: PMC6719146 DOI: 10.3390/molecules24162974] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 08/11/2019] [Accepted: 08/15/2019] [Indexed: 12/15/2022] Open
Abstract
Dermaseptins belonging to a large family of cationic membrane-disruption antimicrobial peptides display extensive antibacterial and antiproliferative activities depending on a coil-to-helix transition and the specific structural parameters. Herein, a novel dermaseptin peptide named Der-PS4 was discovered from the skin secretion of the waxy monkey tree frog, Phyllomedusa sauvagii. The complementary DNA (cDNA)-encoding precursor was obtained relying on "shotgun" cloning, and afterwards, a mature peptide amino acid sequence was identified by reverse-phase high performance liquid chromatography (RP-HPLC) and MS/MS. Specimens were chemically synthesized and applied for further functional studies. Structural analysis demonstrated a higher α-helical content in the membrane-mimetic environment compared with that in the ammonium acetate/water circumstance. Der-PS4 displayed a broad spectrum of antimicrobial activities against tested pathogenic microorganisms, however, exhibiting slight membrane-damaging effectiveness towards horse red blood cells. Coincident with the inhibitory activities on pathogens, Der-PS4 also showed considerable biofilm eradicating impact. Also, Der-PS4 penetrated cell membrane in a relative short period under each minimum bactericidal concentration. In addition, Der-PS4 possessed antiproliferative capacity against five cancer cell lines, while presenting slight suppressing effect on human microvascular endothelial, HMEC-1. These findings provide a promising insight for the discovery and development of novel drugs from a natural source.
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Affiliation(s)
- Dong Chen
- Natural Drug Discovery Group, School of Pharmacy, Queen's University, Belfast BT9 7BL, UK
| | - Xiaowei Zhou
- Natural Drug Discovery Group, School of Pharmacy, Queen's University, Belfast BT9 7BL, UK
- Department of Nutrition, Henry Fok School of Food Science and Engineering, Shaoguan University, Shaoguan 512005, China
| | - Xi Chen
- Natural Drug Discovery Group, School of Pharmacy, Queen's University, Belfast BT9 7BL, UK
| | - Linyuan Huang
- Natural Drug Discovery Group, School of Pharmacy, Queen's University, Belfast BT9 7BL, UK.
- School of Life Sciences and Technology, China Pharmaceutical University, Nanjing 211198, China.
| | - Xinping Xi
- Natural Drug Discovery Group, School of Pharmacy, Queen's University, Belfast BT9 7BL, UK.
| | - Chengbang Ma
- Natural Drug Discovery Group, School of Pharmacy, Queen's University, Belfast BT9 7BL, UK
| | - Mei Zhou
- Natural Drug Discovery Group, School of Pharmacy, Queen's University, Belfast BT9 7BL, UK
| | - Lei Wang
- Natural Drug Discovery Group, School of Pharmacy, Queen's University, Belfast BT9 7BL, UK
| | - Tianbao Chen
- Natural Drug Discovery Group, School of Pharmacy, Queen's University, Belfast BT9 7BL, UK
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25
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Hughes DF, Green ML, Warner JK, Davidson PC. There's a frog in my salad! A review of online media coverage for wild vertebrates found in prepackaged produce in the United States. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 675:1-12. [PMID: 31022609 DOI: 10.1016/j.scitotenv.2019.03.254] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 03/12/2019] [Accepted: 03/17/2019] [Indexed: 06/09/2023]
Abstract
Prepackaged leafy green vegetables represent one of the fastest growing segments of the fresh-produce industry in the United States. Several steps in the production process have been mechanized to meet the downstream demand for prebagged lettuces. The growth in this market, however, has come with drawbacks, and chief among them are consumers finding wild animals in prepackaged crops. These incidents may signal an overburdened produce supply chain, but we currently lack the information needed to determine if this is a food-safety problem or food-quality concern. Here, we address this gap by reviewing online media coverage of wild vertebrates found in prepackaged produce items by customers in the United States. We discovered 40 independent incidents since 2003 with 95% having occurred during 2008-2018, suggesting that the frequency of incidents may have increased during the last decade. The minority of incidents included wild animals found in organic produce (27.5%), whereas the majority involved conventionally grown crops (72.5%). Most incidents involved amphibians (52.5%) and reptiles (22.5%), while fewer contained mammals (17.5%) and birds (7.5%). Frogs and toads made up all of the amphibian-related incidents, with more than 60% comprising small-bodied treefrogs found in various types of fresh leafy greens. At least seven incidents involved Pacific Treefrogs (Hyliola regilla) and three comprised Green Anoles (Anolis carolinensis). One lizard and nine frogs were found alive, and at least two frogs were released into non-native areas. This is the first review quantifying incidents of vertebrates found by customers in prepackaged produce, yet it remains unclear whether these occurrences indicate a food-safety crisis or a complaint against food quality. Nevertheless, wild animals can spread diseases to humans via contaminated produce, therefore we contend that industry professionals can reduce the potential health risk to their consumers and negative economic consequences to themselves through increased attention to this matter.
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Affiliation(s)
- Daniel F Hughes
- Department of Animal Sciences, University of Illinois Urbana-Champaign, 1207 West Gregory Drive, Urbana, IL 61801, USA; Department of Agricultural and Biological Engineering, University of Illinois Urbana-Champaign, 1304 West Pennsylvania Avenue, Urbana, IL 61801, USA.
| | - Michelle L Green
- Department of Animal Sciences, University of Illinois Urbana-Champaign, 1207 West Gregory Drive, Urbana, IL 61801, USA; Department of Biological Sciences, University of South Florida Saint Petersburg, 140 7th Avenue South, Saint Petersburg, FL 33701, USA
| | - Jonathan K Warner
- Texas Parks & Wildlife Department, 10 Parks and Wildlife Drive, Port Arthur, TX 77640, USA
| | - Paul C Davidson
- Department of Agricultural and Biological Engineering, University of Illinois Urbana-Champaign, 1304 West Pennsylvania Avenue, Urbana, IL 61801, USA.
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26
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Biofilms: Novel Strategies Based on Antimicrobial Peptides. Pharmaceutics 2019; 11:pharmaceutics11070322. [PMID: 31295834 PMCID: PMC6680976 DOI: 10.3390/pharmaceutics11070322] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 06/24/2019] [Accepted: 07/06/2019] [Indexed: 01/11/2023] Open
Abstract
The problem of drug resistance is very worrying and ever increasing. Resistance is due not only to the reckless use of antibiotics but also to the fact that pathogens are able to adapt to different conditions and develop self-defense mechanisms such as living in biofilms; altogether these issues make the search for alternative drugs a real challenge. Antimicrobial peptides appear as promising alternatives but they have disadvantages that do not make them easily applicable in the medical field; thus many researches look for solutions to overcome the disadvantages and ensure that the advantages can be exploited. This review describes the biofilm characteristics and identifies the key features that antimicrobial peptides should have. Recalcitrant bacterial infections caused by the most obstinate bacterial species should be treated with a strategy to combine conventional peptides functionalized with nano-tools. This approach could effectively disrupt high density infections caused by biofilms. Moreover, the importance of using in vivo non mammalian models for biofilm studies is described. In particular, here we analyze the use of amphibians as a model to substitute the rodent model.
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27
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LFB: A Novel Antimicrobial Brevinin-Like Peptide from the Skin Secretion of the Fujian Large Headed Frog, Limnonectes fujianensi. Biomolecules 2019; 9:biom9060242. [PMID: 31234333 PMCID: PMC6627297 DOI: 10.3390/biom9060242] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 05/27/2019] [Accepted: 05/27/2019] [Indexed: 12/22/2022] Open
Abstract
Amphibians are a natural source of abundant antimicrobial peptides and thus have been widely investigated for isolation of such biomolecules. Many new antimicrobial peptide families have been discovered from amphibians. In this study, a novel antimicrobial peptide named Limnonectes fujianensis Brevinvin (LFB) has been identified in the skin secretion from the Fujian large headed frog, Limnonectes fujianensis. The cDNA sequence was cloned from a skin secretion library and the predicted mature peptide was identified through MS/MS fragmentation sequencing of reverse phase HPLC fractions on the same sample. LFB was predicted to be an amphipathic, hydrophobic, alpha helical, and beta turn peptide that inserts into a lipid bilayer in order to kill the cells. In antimicrobial assays, a synthetic replicate of this novel antimicrobial peptide demonstrated significant activity against the Gram-positive bacterium Staphylococcus aureus, the Gram-negative bacterium Escherichia coli and the yeast, Candida albicans. This novel peptide was highly potent (MIC 4.88 uM) against Gram-negative bacterium, and also has the ability to inhibit the growth of human cancer cell lines with IC50 values ranging from 18.9 μM down to 2.0 μM. These findings help to enrich our understanding of Brevinin-like peptides. Moreover, the data presented here validate frog secretion as a source of potential novel antimicrobial peptides, that also exhibit anti-tumor properties, that could be useful for the treatment of cancer.
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28
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Varga JFA, Bui-Marinos MP, Katzenback BA. Frog Skin Innate Immune Defences: Sensing and Surviving Pathogens. Front Immunol 2019; 9:3128. [PMID: 30692997 PMCID: PMC6339944 DOI: 10.3389/fimmu.2018.03128] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 12/18/2018] [Indexed: 01/26/2023] Open
Abstract
Amphibian skin is a mucosal surface in direct and continuous contact with a microbially diverse and laden aquatic and/or terrestrial environment. As such, frog skin is an important innate immune organ and first line of defence against pathogens in the environment. Critical to the innate immune functions of frog skin are the maintenance of physical, chemical, cellular, and microbiological barriers and the complex network of interactions that occur across all the barriers. Despite the global decline in amphibian populations, largely as a result of emerging infectious diseases, we understand little regarding the cellular and molecular mechanisms that underlie the innate immune function of amphibian skin and defence against pathogens. In this review, we discuss the structure, cell composition and cellular junctions that contribute to the skin physical barrier, the antimicrobial peptide arsenal that, in part, comprises the chemical barrier, the pattern recognition receptors involved in recognizing pathogens and initiating innate immune responses in the skin, and the contribution of commensal microbes on the skin to pathogen defence. We briefly discuss the influence of environmental abiotic factors (natural and anthropogenic) and pathogens on the immunocompetency of frog skin defences. Although some aspects of frog innate immunity, such as antimicrobial peptides are well-studied; other components and how they contribute to the skin innate immune barrier, are lacking. Elucidating the complex network of interactions occurring at the interface of the frog's external and internal environments will yield insight into the crucial role amphibian skin plays in host defence and the environmental factors leading to compromised barrier integrity, disease, and host mortality.
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Affiliation(s)
- Joseph F A Varga
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
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29
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Rončević T, Gerdol M, Spazzali F, Florian F, Mekinić S, Tossi A, Pallavicini A. Parallel identification of novel antimicrobial peptide sequences from multiple anuran species by targeted DNA sequencing. BMC Genomics 2018; 19:827. [PMID: 30458708 PMCID: PMC6245896 DOI: 10.1186/s12864-018-5225-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 11/06/2018] [Indexed: 12/20/2022] Open
Abstract
Background Antimicrobial peptides (AMPs) are multifunctional effector molecules that often combine direct antimicrobial activities with signaling or immunomodulatory functions. The skin secretions of anurans contain a variety of such bioactive peptides. The identification of AMPs from frog species often requires sacrificing several specimens to obtain small quantities of crude peptides, followed by activity based fractionation to identify the active principles. Results We report an efficient alternative approach to selectively amplify AMP-coding transcripts from very small amounts of tissue samples, based on RNA extraction and cDNA synthesis, followed by PCR amplification and high-throughput sequencing of size-selected amplicons. This protocol exploits the highly conserved signal peptide region of the AMP precursors from Ranidae, Hylidae and Bombinatoridae for the design of family-specific, forward degenerate primers, coupled with a reverse primer targeting the mRNA poly-A tail. Conclusions Analysis of the assembled sequencing output allowed to identify more than a hundred full-length mature peptides, mostly from Ranidae species, including several novel potential AMPs for functional characterization. This (i) confirms the effectiveness of the experimental approach and indicates points for protocol optimization to account for particular cases, and (ii) encourages the application of the same methodology to other multigenic AMP families, also from other genera, sharing common features as in anuran AMPs. Electronic supplementary material The online version of this article (10.1186/s12864-018-5225-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tomislav Rončević
- Department of Physics, Faculty of Science, University of Split, 21000, Split, Croatia.
| | - Marco Gerdol
- Department of Life Sciences, University of Trieste, 34127, Trieste, Italy
| | - Francesca Spazzali
- Department of Life Sciences, University of Trieste, 34127, Trieste, Italy
| | - Fiorella Florian
- Department of Life Sciences, University of Trieste, 34127, Trieste, Italy
| | - Stjepan Mekinić
- Public Institution for the Management of Protected Areas in the County of Split and Dalmatia - "Sea and karst", 21000, Split, Croatia
| | - Alessandro Tossi
- Department of Life Sciences, University of Trieste, 34127, Trieste, Italy
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30
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Weitzman CL, Gibb K, Christian K. Skin bacterial diversity is higher on lizards than sympatric frogs in tropical Australia. PeerJ 2018; 6:e5960. [PMID: 30479906 PMCID: PMC6240339 DOI: 10.7717/peerj.5960] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 10/18/2018] [Indexed: 12/24/2022] Open
Abstract
Animal skin acts as a barrier between the organism and its environment and provides the first line of defense against invading pathogens. Thus, skin surfaces harbor communities of microbes that are interacting with both the host and its environment. Amphibian skin bacteria form distinct communities closely tied to their host species, but few studies have compared bacterial communities between amphibians and other, non-amphibian sympatric animals. Notably, skin microbes on reptiles have gained little attention. We used next-generation sequencing technology to describe bacterial communities on the skin of three lizard species and compared them to bacteria on six cohabiting frog species in the Northern Territory of Australia. We found bacterial communities had higher richness and diversity on lizards than frogs, with different community composition between reptiles and amphibians and among species. Core bacteria on the three lizard species overlapped by over 100 operational taxonomic units. The bacterial communities were similar within species of frogs and lizards, but the communities tended to be more similar between lizard species than between frog species and when comparing lizards with frogs. The diverse bacteria found on lizards invites further questions on how and how well reptiles interact with microorganisms through their scaly skin.
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Affiliation(s)
- Chava L. Weitzman
- Independent Researcher, Millburn, NJ, United States of America
- Department of Biology, University of Nevada—Reno, Reno, NV, United States of America
| | - Karen Gibb
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina, Northern Territory, Australia
| | - Keith Christian
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina, Northern Territory, Australia
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31
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Grogan LF, Robert J, Berger L, Skerratt LF, Scheele BC, Castley JG, Newell DA, McCallum HI. Review of the Amphibian Immune Response to Chytridiomycosis, and Future Directions. Front Immunol 2018; 9:2536. [PMID: 30473694 PMCID: PMC6237969 DOI: 10.3389/fimmu.2018.02536] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 10/15/2018] [Indexed: 12/27/2022] Open
Abstract
The fungal skin disease, chytridiomycosis (caused by Batrachochytrium dendrobatidis and B. salamandrivorans), has caused amphibian declines and extinctions globally since its emergence. Characterizing the host immune response to chytridiomycosis has been a focus of study with the aim of disease mitigation. However, many aspects of the innate and adaptive arms of this response are still poorly understood, likely due to the wide range of species' responses to infection. In this paper we provide an overview of expected immunological responses (with inference based on amphibian and mammalian immunology), together with a synthesis of current knowledge about these responses for the amphibian-chytridiomycosis system. We structure our review around four key immune stages: (1) the naïve immunocompetent state, (2) immune defenses that are always present (constitutive defenses), (3) mechanisms for recognition of a pathogen threat and innate immune defenses, and (4) adaptive immune responses. We also evaluate the current hot topics of immunosuppression and immunopathology in chytridiomycosis, and discuss their respective roles in pathogenesis. Our synthesis reveals that susceptibility to chytridiomycosis is likely to be multifactorial. Susceptible amphibians appear to have ineffective constitutive and innate defenses, and a late-stage response characterized by immunopathology and Bd-induced suppression of lymphocyte responses. Overall, we identify substantial gaps in current knowledge, particularly concerning the entire innate immune response (mechanisms of initial pathogen detection and possible immunoevasion by Bd, degree of activation and efficacy of the innate immune response, the unexpected absence of innate leukocyte infiltration, and the cause and role of late-stage immunopathology in pathogenesis). There are also gaps concerning most of the adaptive immune system (the relative importance of B and T cell responses for pathogen clearance, the capacity and extent of immunological memory, and specific mechanisms of pathogen-induced immunosuppression). Improving our capacity for amphibian immunological research will require selection of an appropriate Bd-susceptible model species, the development of taxon-specific affinity reagents and cell lines for functional assays, and the application of a suite of conventional and emerging immunological methods. Despite current knowledge gaps, immunological research remains a promising avenue for amphibian conservation management.
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Affiliation(s)
- Laura F Grogan
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Nathan, QLD, Australia
| | - Jacques Robert
- University of Rochester Medical Center, Rochester, NY, United States
| | - Lee Berger
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia.,Faculty of Veterinary and Agricultural Sciences, Melbourne Veterinary School, University of Melbourne, Werribee, VIC, Australia
| | - Lee F Skerratt
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia.,Faculty of Veterinary and Agricultural Sciences, Melbourne Veterinary School, University of Melbourne, Werribee, VIC, Australia
| | - Benjamin C Scheele
- Fenner School of Environment and Society, The Australian National University, Canberra, ACT, Australia.,Threatened Species Recovery Hub, National Environmental Science Program, Fenner School of Environment and Society, The Australian National University, Canberra, ACT, Australia
| | - J Guy Castley
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Nathan, QLD, Australia
| | - David A Newell
- Forest Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW, Australia
| | - Hamish I McCallum
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Nathan, QLD, Australia
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Raaymakers C, Verbrugghe E, Stijlemans B, Martel A, Pasmans F, Roelants K. The anuran skin peptide bradykinin mediates its own absorption across epithelial barriers of the digestive tract. Peptides 2018; 103:84-89. [PMID: 29571654 DOI: 10.1016/j.peptides.2018.03.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Revised: 03/14/2018] [Accepted: 03/15/2018] [Indexed: 01/23/2023]
Abstract
When faced with a potential predator, a wide range of frog species secrete a mixture of peptide toxins from their skin to defend themselves. We have recently shown that antimicrobial peptides (AMPs) in a frog's defensive poison enhance the uptake of these peptides across epithelia, thereby speeding up the process of predator intoxication. This study provides evidence that bradykinin, a widespread peptide toxin in anurans (frogs), is capable to pass through epithelial barriers independent of this delivery system. We quantified bradykinin peptides secreted by Bombina orientalis during acute stress, and found that at biologically relevant concentrations, bradykinin passage across model epithelia occurs even in the absence of AMPs. Monitoring of transepithelial electric resistance showed that bradykinin treatment caused a subtle yet prolonged reduction in barrier function, indicating that the peptide itself is capable to increase the permeability of epithelia. Yet, bradykinin does not cause cells to leak lactate dehydrogenase, suggesting that it does not damage cell membranes. Moreover, imaging of bradykinin-treated monolayers shows no endocytosis of fluorescent propidium iodide, indicating that the peptide does not perforate cell membranes at smaller scale and therefore is unlikely to cross epithelia via a transcellular passage. Together, these observations suggest that bradykinin, unlike other amphibian neuropeptide toxins, mediates its own passage across mucosal barriers, possibly through a paracellular route. This "self-administering" property, combined with the fact that bradykinins can potently disturb multiple physiological processes, could explain why these peptides are one of the most widespread antipredator peptides in the defensive secretions of frogs.
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Affiliation(s)
- Constantijn Raaymakers
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Elsene, Belgium; Department of Pathology, Bacteriology, and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Elin Verbrugghe
- Department of Pathology, Bacteriology, and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Benoit Stijlemans
- Unit of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Elsene, Belgium; Myeloid Cell Immunology Lab, VIB Centre for Inflammation Research, Brussels, Belgium
| | - An Martel
- Department of Pathology, Bacteriology, and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Frank Pasmans
- Department of Pathology, Bacteriology, and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Kim Roelants
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Elsene, Belgium.
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Gomes KAGG, Dos Santos DM, Santos VM, Piló-Veloso D, Mundim HM, Rodrigues LV, Lião LM, Verly RM, de Lima ME, Resende JM. NMR structures in different membrane environments of three ocellatin peptides isolated from Leptodactylus labyrinthicus. Peptides 2018; 103:72-83. [PMID: 29596881 DOI: 10.1016/j.peptides.2018.03.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 03/21/2018] [Accepted: 03/23/2018] [Indexed: 10/17/2022]
Abstract
The peptides ocellatin-LB1, -LB2 and -F1 have previously been isolated from anurans of the Leptodactylus genus and the sequences are identical from residue 1-22, which correspond to ocellatin-LB1 sequence (GVVDILKGAAKDIAGHLASKVM-NH2), whereas ocellatin-LB2 carries an extra N and ocellatin-F1 extra NKL residues at their C-termini. These peptides showed different spectra of activities and biophysical investigations indicated a direct correlation between membrane-disruptive properties and antimicrobial activities, i.e. ocellatin-F1 > ocellatin-LB1 > ocellatin-LB2. To better characterize their membrane interactions, we report here the detailed three-dimensional NMR structures of these peptides in TFE-d2:H2O (60:40) and in the presence of zwitterionic DPC-d38 and anionic SDS-d25 micellar solutions. Although the three peptides showed significant helical contents in the three mimetic environments, structural differences were noticed. When the structures of the three peptides in the presence of DPC-d38 micelles are compared to each other, a more pronounced curvature is observed for ocellatin-F1 and the bent helix, with the concave face composed mostly of hydrophobic residues, is consistent with the micellar curvature and the amphipathic nature of the molecule. Interestingly, an almost linear helical segment was observed for ocellatin-F1 in the presence of SDS-d25 micelles and the conformational differences in the two micellar environments are possibly related to the presence of the extra Lys residue near the peptide C-terminus, which increases the affinity of ocellatin-F1 to anionic membranes in comparison with ocellatin-LB1 and -LB2, as proved by isothermal titration calorimetry. To our knowledge, this work reports for the first time the three-dimensional structures of ocellatin peptides.
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Affiliation(s)
- Karla A G G Gomes
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, P.O. Box 486, 31270-901 Belo Horizonte, MG, Brazil; Instituto de Engenharia, Ciência e Tecnologia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 39440-000 Janaúba, MG, Brazil
| | - Daniel M Dos Santos
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, P.O. Box 486, 31270-901 Belo Horizonte, MG, Brazil
| | - Virgílio M Santos
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, P.O. Box 486, 31270-901 Belo Horizonte, MG, Brazil
| | - Dorila Piló-Veloso
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, P.O. Box 486, 31270-901 Belo Horizonte, MG, Brazil
| | - Higor M Mundim
- Instituto de Química, Universidade Federal de Goiás, Av. Esperança, s/n, Campus Samambaia, 74690-900 Goiânia, GO, Brazil
| | - Leticia V Rodrigues
- Instituto de Química, Universidade Federal de Goiás, Av. Esperança, s/n, Campus Samambaia, 74690-900 Goiânia, GO, Brazil
| | - Luciano M Lião
- Instituto de Química, Universidade Federal de Goiás, Av. Esperança, s/n, Campus Samambaia, 74690-900 Goiânia, GO, Brazil
| | - Rodrigo M Verly
- Departamento de Química, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 39100-000 Diamantina, MG, Brazil
| | - Maria Elena de Lima
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, P.O. Box 486, 31270-901 Belo Horizonte, MG, Brazil
| | - Jarbas M Resende
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, P.O. Box 486, 31270-901 Belo Horizonte, MG, Brazil.
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Johnson PTJ, Calhoun DM, Stokes AN, Susbilla CB, McDevitt-Galles T, Briggs CJ, Hoverman JT, Tkach VV, de Roode JC. Of poisons and parasites-the defensive role of tetrodotoxin against infections in newts. J Anim Ecol 2018; 87:1192-1204. [PMID: 29476541 DOI: 10.1111/1365-2656.12816] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 01/17/2018] [Indexed: 11/29/2022]
Abstract
Classical research on animal toxicity has focused on the role of toxins in protection against predators, but recent studies suggest these same compounds can offer a powerful defense against parasites and infectious diseases. Newts in the genus Taricha are brightly coloured and contain the potent neurotoxin, tetrodotoxin (TTX), which is hypothesized to have evolved as a defense against vertebrate predators such as garter snakes. However, newt populations often vary dramatically in toxicity, which is only partially explained by predation pressure. The primary aim of this study was to evaluate the relationships between TTX concentration and infection by parasites. By systematically assessing micro- and macroparasite infections among 345 adult newts (sympatric populations of Taricha granulosa and T. torosa), we detected 18 unique taxa of helminths, fungi, viruses and protozoans. For both newt species, per-host concentrations of TTX, which varied from undetectable to >60 μg/cm2 skin, negatively predicted overall parasite richness as well as the likelihood of infection by the chytrid fungus, Batrachochytrium dendrobatidis, and ranavirus. No such effect was found on infection load among infected hosts. Despite commonly occurring at the same wetlands, T. torosa supported higher parasite richness and average infection load than T. granulosa. Host body size and sex (females > males) tended to positively predict infection levels in both species. For hosts in which we quantified leucocyte profiles, total white blood cell count correlated positively with both parasite richness and total infection load. By coupling data on host toxicity and infection by a broad range of micro- and macroparasites, these results suggest that-alongside its effects on predators-tetrodotoxin may help protect newts against parasitic infections, highlighting the importance of integrative research on animal chemistry, immunological defenses and natural enemy ecology.
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Affiliation(s)
- Pieter T J Johnson
- Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, Boulder, CO, USA
| | - Dana M Calhoun
- Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, Boulder, CO, USA
| | - Amber N Stokes
- Department of Biology, California State University, Bakersfield, CA, USA
| | - Calvin B Susbilla
- Department of Biology, California State University, Bakersfield, CA, USA
| | - Travis McDevitt-Galles
- Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, Boulder, CO, USA
| | - Cheryl J Briggs
- Ecology, Evolution and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Jason T Hoverman
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN, USA
| | - Vasyl V Tkach
- Department of Biology, University of North Dakota, Grand Forks, ND, USA
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Prest TL, Kimball AK, Kueneman JG, McKenzie VJ. Host-associated bacterial community succession during amphibian development. Mol Ecol 2018; 27:1992-2006. [DOI: 10.1111/mec.14507] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 12/22/2017] [Accepted: 01/02/2018] [Indexed: 12/18/2022]
Affiliation(s)
- Tiffany L. Prest
- Department of Ecology and Evolutionary Biology; University of Colorado at Boulder; Boulder CO USA
- Department of Biology; Duke University; Durham NC USA
| | - Abigail K. Kimball
- Department of Ecology and Evolutionary Biology; University of Colorado at Boulder; Boulder CO USA
- Department of Microbiology and Immunology; Anschutz Medical Campus; Aurora CO USA
| | - Jordan G. Kueneman
- Department of Ecology and Evolutionary Biology; University of Colorado at Boulder; Boulder CO USA
- Smithsonian Tropical Research Institute; Panama City Panama
| | - Valerie J. McKenzie
- Department of Ecology and Evolutionary Biology; University of Colorado at Boulder; Boulder CO USA
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36
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Rebollar EA, Gutiérrez-Preciado A, Noecker C, Eng A, Hughey MC, Medina D, Walke JB, Borenstein E, Jensen RV, Belden LK, Harris RN. The Skin Microbiome of the Neotropical Frog Craugastor fitzingeri: Inferring Potential Bacterial-Host-Pathogen Interactions From Metagenomic Data. Front Microbiol 2018; 9:466. [PMID: 29615997 PMCID: PMC5869913 DOI: 10.3389/fmicb.2018.00466] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 02/28/2018] [Indexed: 01/01/2023] Open
Abstract
Skin symbiotic bacteria on amphibians can play a role in protecting their host against pathogens. Chytridiomycosis, the disease caused by Batrachochytrium dendrobatidis, Bd, has caused dramatic population declines and extinctions of amphibians worldwide. Anti-Bd bacteria from amphibian skin have been cultured, and skin bacterial communities have been described through 16S rRNA gene amplicon sequencing. Here, we present a shotgun metagenomic analysis of skin bacterial communities from a Neotropical frog, Craugastor fitzingeri. We sequenced the metagenome of six frogs from two different sites in Panamá: three frogs from Soberanía (Sob), a Bd-endemic site, and three frogs from Serranía del Sapo (Sapo), a Bd-naïve site. We described the taxonomic composition of skin microbiomes and found that Pseudomonas was a major component of these communities. We also identified that Sob communities were enriched in Actinobacteria while Sapo communities were enriched in Gammaproteobacteria. We described gene abundances within the main functional classes and found genes enriched either in Sapo or Sob. We then focused our study on five functional classes of genes: biosynthesis of secondary metabolites, metabolism of terpenoids and polyketides, membrane transport, cellular communication and antimicrobial drug resistance. These gene classes are potentially involved in bacterial communication, bacterial-host and bacterial-pathogen interactions among other functions. We found that C. fitzingeri metagenomes have a wide array of genes that code for secondary metabolites, including antibiotics and bacterial toxins, which may be involved in bacterial communication, but could also have a defensive role against pathogens. Several genes involved in bacterial communication and bacterial-host interactions, such as biofilm formation and bacterial secretion systems were found. We identified specific genes and pathways enriched at the different sites and determined that gene co-occurrence networks differed between sites. Our results suggest that skin microbiomes are composed of distinct bacterial taxa with a wide range of metabolic capabilities involved in bacterial defense and communication. Differences in taxonomic composition and pathway enrichments suggest that skin microbiomes from different sites have unique functional properties. This study strongly supports the need for shotgun metagenomic analyses to describe the functional capacities of skin microbiomes and to tease apart their role in host defense against pathogens.
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Affiliation(s)
- Eria A Rebollar
- Department of Biology, James Madison University, Harrisonburg, VA, United States
| | | | - Cecilia Noecker
- Department of Genome Sciences, University of Washington, Seattle, WA, United States
| | - Alexander Eng
- Department of Genome Sciences, University of Washington, Seattle, WA, United States
| | - Myra C Hughey
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Daniel Medina
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Jenifer B Walke
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Elhanan Borenstein
- Department of Genome Sciences, University of Washington, Seattle, WA, United States.,Department of Computer Science and Engineering, University of Washington, Seattle, WA, United States.,Santa Fe Institute, Santa Fe, NM, United States
| | - Roderick V Jensen
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Lisa K Belden
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States.,Smithsonian Tropical Research Institution, Panama City, Panama
| | - Reid N Harris
- Department of Biology, James Madison University, Harrisonburg, VA, United States.,Amphibian Survival Alliance, London, United Kingdom
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37
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Hovey KJ, Seiter EM, Johnson EE, Saporito RA. Sequestered Alkaloid Defenses in the Dendrobatid Poison Frog Oophaga pumilio Provide Variable Protection from Microbial Pathogens. J Chem Ecol 2018; 44:312-325. [PMID: 29427191 DOI: 10.1007/s10886-018-0930-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 01/26/2018] [Accepted: 01/29/2018] [Indexed: 11/29/2022]
Abstract
Most amphibians produce their own defensive chemicals; however, poison frogs sequester their alkaloid-based defenses from dietary arthropods. Alkaloids function as a defense against predators, and certain types appear to inhibit microbial growth. Alkaloid defenses vary considerably among populations of poison frogs, reflecting geographic differences in availability of dietary arthropods. Consequently, environmentally driven differences in frog defenses may have significant implications regarding their protection against pathogens. While natural alkaloid mixtures in dendrobatid poison frogs have recently been shown to inhibit growth of non-pathogenic microbes, no studies have examined the effectiveness of alkaloids against microbes that infect these frogs. Herein, we examined how alkaloid defenses in the dendrobatid poison frog, Oophaga pumilio, affect growth of the known anuran pathogens Aeromonas hydrophila and Klebsiella pneumoniae. Frogs were collected from five locations throughout Costa Rica that are known to vary in their alkaloid profiles. Alkaloids were isolated from individual skins, and extracts were assayed against both pathogens. Microbe subcultures were inoculated with extracted alkaloids to create dose-response curves. Subsequent spectrophotometry and cell counting assays were used to assess growth inhibition. GC-MS was used to characterize and quantify alkaloids in frog extracts, and our results suggest that variation in alkaloid defenses lead to differences in inhibition of these pathogens. The present study provides the first evidence that alkaloid variation in a dendrobatid poison frog is associated with differences in inhibition of anuran pathogens, and offers further support that alkaloid defenses in poison frogs confer protection against both pathogens and predators.
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Affiliation(s)
- Kyle J Hovey
- Department of Biology, John Carroll University, University Heights, OH, 44118, USA
| | - Emily M Seiter
- Department of Biology, John Carroll University, University Heights, OH, 44118, USA
| | - Erin E Johnson
- Department of Biology, John Carroll University, University Heights, OH, 44118, USA
| | - Ralph A Saporito
- Department of Biology, John Carroll University, University Heights, OH, 44118, USA.
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38
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Pantic JM, Jovanovic IP, Radosavljevic GD, Arsenijevic NN, Conlon JM, Lukic ML. The Potential of Frog Skin-Derived Peptides for Development into Therapeutically-Valuable Immunomodulatory Agents. Molecules 2017; 22:E2071. [PMID: 29236056 PMCID: PMC6150033 DOI: 10.3390/molecules22122071] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 11/20/2017] [Accepted: 11/23/2017] [Indexed: 12/19/2022] Open
Abstract
The aim of this article is to review the immunoregulatory actions of frog skin-derived peptides in order to assess their potential as candidates for immunomodulatory or anti-inflammatory therapy. Frog skin peptides with demonstrable immunomodulatory properties have been isolated from skin secretions of a range of species belonging to the families Alytidae, Ascaphidae, Discoglossidae, Leptodactylidae, Pipidae and Ranidae. Their effects upon production of inflammatory and immunoregulatory cytokines by target cells have been evaluated ex vivo and effects upon cytokine expression and immune cell activity have been studied in vivo by flow cytometry after injection into mice. The naturally-occurring peptides and/or their synthetic analogues show complex and variable actions on the production of proinflammatory (TNF-α, IL-1β, IL-12, IL-23, IL-8, IFN-γ and IL-17), pleiotropic (IL-4 and IL-6) and immunosuppressive (IL-10 and TGF-β) cytokines by peripheral and spleen cells, peritoneal cells and/or isolated macrophages. The effects of frenatin 2.1S include enhancement of the activation state and homing capacity of Th1-type lymphocytes and NK cells in the mouse peritoneal cavity, as well as the promotion of their tumoricidal capacities. Overall, the diverse effects of frog skin-derived peptides on the immune system indicate their potential for development into therapeutic agents.
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Affiliation(s)
- Jelena M Pantic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, 34000 Kragujevac, Serbia.
| | - Ivan P Jovanovic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, 34000 Kragujevac, Serbia.
| | - Gordana D Radosavljevic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, 34000 Kragujevac, Serbia.
| | - Nebojsa N Arsenijevic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, 34000 Kragujevac, Serbia.
| | - J Michael Conlon
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Cromore Road, Coleraine, Northern Ireland BT52 1SA, UK.
| | - Miodrag L Lukic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, 34000 Kragujevac, Serbia.
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Raaymakers C, Verbrugghe E, Hernot S, Hellebuyck T, Betti C, Peleman C, Claeys M, Bert W, Caveliers V, Ballet S, Martel A, Pasmans F, Roelants K. Antimicrobial peptides in frog poisons constitute a molecular toxin delivery system against predators. Nat Commun 2017; 8:1495. [PMID: 29138448 PMCID: PMC5686178 DOI: 10.1038/s41467-017-01710-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 10/10/2017] [Indexed: 01/08/2023] Open
Abstract
Animals using toxic peptides and proteins for predation or defense typically depend on specialized morphological structures, like fangs, spines, or a stinger, for effective intoxication. Here we show that amphibian poisons instead incorporate their own molecular system for toxin delivery to attacking predators. Skin-secreted peptides, generally considered part of the amphibian immune system, permeabilize oral epithelial tissue and enable fast access of cosecreted toxins to the predator's bloodstream and organs. This absorption-enhancing system exists in at least three distantly related frog lineages and is likely to be a widespread adaptation, determining the outcome of predator-prey encounters in hundreds of species.
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Affiliation(s)
- Constantijn Raaymakers
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Elsene, Belgium.,Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - Elin Verbrugghe
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - Sophie Hernot
- Department of Nuclear Medicine, UZ Brussel and In vivo Cellular and Molecular Imaging, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Jette, Belgium
| | - Tom Hellebuyck
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - Cecilia Betti
- Research Group of Organic Chemistry, Department of Chemistry and Department of Bio-engineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Elsene, Belgium
| | - Cindy Peleman
- Department of Nuclear Medicine, UZ Brussel and In vivo Cellular and Molecular Imaging, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Jette, Belgium
| | - Myriam Claeys
- Department of Biology, Nematology Research Unit, Faculty of Science, Ghent University, 9000, Ghent, Belgium
| | - Wim Bert
- Department of Biology, Nematology Research Unit, Faculty of Science, Ghent University, 9000, Ghent, Belgium
| | - Vicky Caveliers
- Department of Nuclear Medicine, UZ Brussel and In vivo Cellular and Molecular Imaging, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Jette, Belgium
| | - Steven Ballet
- Research Group of Organic Chemistry, Department of Chemistry and Department of Bio-engineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Elsene, Belgium
| | - An Martel
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - Kim Roelants
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Elsene, Belgium.
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40
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Barnhart K, Forman ME, Umile TP, Kueneman J, McKenzie V, Salinas I, Minbiole KPC, Woodhams DC. Identification of Bufadienolides from the Boreal Toad, Anaxyrus boreas, Active Against a Fungal Pathogen. MICROBIAL ECOLOGY 2017; 74:990-1000. [PMID: 28631214 DOI: 10.1007/s00248-017-0997-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 05/12/2017] [Indexed: 05/25/2023]
Abstract
Amphibian granular glands provide a wide range of compounds on the skin that defend against pathogens and predators. We identified three bufadienolides-the steroid-like compounds arenobufagin, gamabufotalin, and telocinobufagin-from the boreal toad, Anaxyrus boreas, through liquid chromatography mass spectrometry (LC/MS). Compounds were detected both after inducing skin gland secretions and in constitutive mucosal rinses from toads. We described the antimicrobial properties of each bufadienolide against Batrachochytrium dendrobatidis (Bd), an amphibian fungal pathogen linked with boreal toad population declines. All three bufadienolides were found to inhibit Bd growth at similar levels. The maximum Bd inhibition produced by arenobufagin, gamabufotalin, and telocinobufagin were approximately 50%, in contrast to the complete Bd inhibition shown by antimicrobial skin peptides produced by some amphibian species. In addition, skin mucus samples significantly reduced Bd viability, and bufadienolides were detected in 15 of 62 samples. Bufadienolides also appeared to enhance growth of the anti-Bd bacterium Janthinobacterium lividum, and thus may be involved in regulation of the skin microbiome. Here, we localized skin bacteria within the mucus layer and granular glands of toads with fluorescent in situ hybridization. Overall, our results suggest that bufadienolides can function in antifungal defense on amphibian skin and their production is a potentially convergent trait similar to antimicrobial peptide defenses found on the skin of other species. Further studies investigating bufadienolide expression across toad populations, their regulation, and interactions with other components of the skin mucosome will contribute to understanding the complexities of amphibian immune defense.
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Affiliation(s)
- Kelly Barnhart
- Department of Biology, University of Massachusetts Boston, Boston, MA, 02125, USA
| | - Megan E Forman
- Department of Chemistry, Villanova University, Villanova, PA, 19085, USA
| | - Thomas P Umile
- Division of Natural and Computational Science, Gwynedd Mercy University, Gwynedd Valley, PA, 19437, USA
| | - Jordan Kueneman
- Department of Ecology and Evolutionary Biology, University of Colorado, Ramaley N122, UCB 334, Boulder, CO, 80309, USA
| | - Valerie McKenzie
- Department of Ecology and Evolutionary Biology, University of Colorado, Ramaley N122, UCB 334, Boulder, CO, 80309, USA
| | - Irene Salinas
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131-0001, USA
| | - Kevin P C Minbiole
- Department of Chemistry, Villanova University, Villanova, PA, 19085, USA.
| | - Douglas C Woodhams
- Department of Biology, University of Massachusetts Boston, Boston, MA, 02125, USA.
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41
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Ujszegi J, Móricz ÁM, Krüzselyi D, Hettyey A. Skin toxin production of toads changes during early ontogeny but is not adjusted to the microbiota of the aquatic environment. Evol Ecol 2017. [DOI: 10.1007/s10682-017-9920-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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42
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Rodeo™ Herbicide Negatively Affects Blanchard's Cricket Frogs (Acris blanchardi) Survival and Alters the Skin-Associated Bacterial Community. J HERPETOL 2017. [DOI: 10.1670/16-092] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Muletz Wolz CR, Yarwood SA, Campbell Grant EH, Fleischer RC, Lips KR. Effects of host species and environment on the skin microbiome of Plethodontid salamanders. J Anim Ecol 2017; 87:341-353. [DOI: 10.1111/1365-2656.12726] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 05/08/2017] [Indexed: 02/05/2023]
Affiliation(s)
- Carly R. Muletz Wolz
- Department of Biology; University of Maryland; College Park MD USA
- Center for Conservation Genomics; Smithsonian Conservation Biology Institute; National Zoological Park; Washington DC USA
| | - Stephanie A. Yarwood
- Department of Environmental Science & Technology; University of Maryland; College Park MD USA
| | - Evan H. Campbell Grant
- S.O. Conte Anadromous Fish Research Laboratory; United States Geological Survey Patuxent Wildlife Research Center; Turners Falls MA USA
| | - Robert C. Fleischer
- Center for Conservation Genomics; Smithsonian Conservation Biology Institute; National Zoological Park; Washington DC USA
| | - Karen R. Lips
- Department of Biology; University of Maryland; College Park MD USA
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Bletz MC, Archer H, Harris RN, McKenzie VJ, Rabemananjara FCE, Rakotoarison A, Vences M. Host Ecology Rather Than Host Phylogeny Drives Amphibian Skin Microbial Community Structure in the Biodiversity Hotspot of Madagascar. Front Microbiol 2017; 8:1530. [PMID: 28861051 PMCID: PMC5563069 DOI: 10.3389/fmicb.2017.01530] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 07/28/2017] [Indexed: 12/30/2022] Open
Abstract
Host-associated microbiotas of vertebrates are diverse and complex communities that contribute to host health. In particular, for amphibians, cutaneous microbial communities likely play a significant role in pathogen defense; however, our ecological understanding of these communities is still in its infancy. Here, we take advantage of the fully endemic and locally species-rich amphibian fauna of Madagascar to investigate the factors structuring amphibian skin microbiota on a large scale. Using amplicon-based sequencing, we evaluate how multiple host species traits and site factors affect host bacterial diversity and community structure. Madagascar is home to over 400 native frog species, all of which are endemic to the island; more than 100 different species are known to occur in sympatry within multiple rainforest sites. We intensively sampled frog skin bacterial communities, from over 800 amphibians from 89 species across 30 sites in Madagascar during three field visits, and found that skin bacterial communities differed strongly from those of the surrounding environment. Richness of bacterial operational taxonomic units (OTUs) and phylogenetic diversity differed among host ecomorphs, with arboreal frogs exhibiting lower richness and diversity than terrestrial and aquatic frogs. Host ecomorphology was the strongest factor influencing microbial community structure, with host phylogeny and site parameters (latitude and elevation) explaining less but significant portions of the observed variation. Correlation analysis and topological congruency analyses revealed little to no phylosymbiosis for amphibian skin microbiota. Despite the observed geographic variation and low phylosymbiosis, we found particular OTUs that were differentially abundant between particular ecomorphs. For example, the genus Pigmentiphaga (Alcaligenaceae) was significantly enriched on arboreal frogs, Methylotenera (Methylophilaceae) was enriched on aquatic frogs, and Agrobacterium (Rhizobiaceae) was enriched on terrestrial frogs. The presence of shared bacterial OTUs across geographic regions for selected host genera suggests the presence of core microbial communities which in Madagascar, might be driven more strongly by a species’ preference for specific microhabitats than by the physical, physiological or biochemical properties of their skin. These results corroborate that both host and environmental factors are driving community assembly of amphibian cutaneous microbial communities, and provide an improved foundation for elucidating their role in disease resistance.
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Affiliation(s)
- Molly C Bletz
- Zoological Institute, Technical University of BraunschweigBraunschweig, Germany.,Department of Biology, James Madison University, HarrisonburgVA, United States
| | - Holly Archer
- Department of Ecology and Evolutionary Biology, University of Colorado BoulderBoulder, CO, United States
| | - Reid N Harris
- Department of Biology, James Madison University, HarrisonburgVA, United States
| | - Valerie J McKenzie
- Department of Ecology and Evolutionary Biology, University of Colorado BoulderBoulder, CO, United States
| | | | - Andolalao Rakotoarison
- Zoological Institute, Technical University of BraunschweigBraunschweig, Germany.,Mention Biologie et Biodiversité Animale, University of AntananarivoAntananarivo, Madagascar
| | - Miguel Vences
- Zoological Institute, Technical University of BraunschweigBraunschweig, Germany
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45
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Owolabi BO, Musale V, Ojo OO, Moffett RC, McGahon MK, Curtis TM, Conlon JM, Flatt PR, Abdel-Wahab YH. Actions of PGLa-AM1 and its [A14K] and [A20K] analogues and their therapeutic potential as anti-diabetic agents. Biochimie 2017; 138:1-12. [DOI: 10.1016/j.biochi.2017.04.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Accepted: 04/04/2017] [Indexed: 12/19/2022]
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46
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Pantic JM, Jovanovic IP, Radosavljevic GD, Gajovic NM, Arsenijevic NN, Conlon JM, Lukic ML. The frog skin host-defense peptide frenatin 2.1S enhances recruitment, activation and tumoricidal capacity of NK cells. Peptides 2017; 93:44-50. [PMID: 28526557 DOI: 10.1016/j.peptides.2017.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 05/14/2017] [Accepted: 05/15/2017] [Indexed: 01/23/2023]
Abstract
Frog skin is a source of peptides with various biological properties. Frenatin 2.1S, derived from norepinephrine-stimulated skin secretions of the Orinoco lime tree frog Sphaenorhynchus lacteus, exhibits immunostimulatory effects as demonstrated by the promotion of proinflammatory phenotypes of mononuclear cells in mouse peritoneal cavity and spleen. The aim of this study was to identify the populations of host cells sensitive to the action of frenatin 2.1S in vivo and to study its effects on their functional antitumor capacity. A single injection of frenatin 2.1S (100μg) in BALB/c mice increased the presence of peritoneal CD11c+ dendritic cells and CD3+ T cells 24h after administration and there was a significant increase in the number of IL-17 and CXCR3 expressing inflammatory T cells. Frenatin 2.1S treatment also increased the number of TNF-α expressing F4/80+ proinflammatory M1 macrophages. The most striking finding of the study is the marked increase of the number of peritoneal natural killer (NK) cells following frenatin 2.1S injection. Further, frenatin 2.1S administration led to activation of NK cells as evaluated by increased expression of NKG2D, FasL, CD69 and CD107a. The increased ratio of interferon-γ vs. IL-10 producing NK cells is further indication of the proinflammatory action of frenatin 2.1S. Peptide treatment enhanced the tumoricidal action of peritoneal NK cells on 4T1 mouse mammary carcinoma cells as revealed by the real-time automated monitoring of cell status. Our data demonstrate that frenatin 2.1S promotes activation and cytotoxic capacity of NK cells and should be regarded as a candidate for antitumor immunotherapy.
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Affiliation(s)
- Jelena M Pantic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Ivan P Jovanovic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Gordana D Radosavljevic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Nevena M Gajovic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Nebojsa N Arsenijevic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - J Michael Conlon
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, Ulster University, Coleraine BT52 1SA, United Kingdom
| | - Miodrag L Lukic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia.
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47
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Ohmer MEB, Cramp RL, Russo CJM, White CR, Franklin CE. Skin sloughing in susceptible and resistant amphibians regulates infection with a fungal pathogen. Sci Rep 2017; 7:3529. [PMID: 28615642 PMCID: PMC5471217 DOI: 10.1038/s41598-017-03605-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 05/05/2017] [Indexed: 11/09/2022] Open
Abstract
The fungal pathogen Batrachochytrium dendrobatidis (Bd) has been implicated in amphibian population declines globally. Given that Bd infection is limited to the skin in post-metamorphic amphibians, routine skin sloughing may regulate infection. Skin sloughing has been shown to reduce the number of cultivatable microbes on amphibian skin, and Bd infection increases skin sloughing rates at high loads. However, it is unclear whether species specific differences in skin sloughing patterns could regulate Bd population growth on the skin, and influence subsequent infection dynamics. We exposed five Australian frog species to Bd, and monitored sloughing rates and infection loads over time. Sloughing reduced Bd load on the ventral skin surface, in all five species, despite wide variation in susceptibility to disease. In the least susceptible species, an increase in sloughing rate occurred at lower infection loads, and sloughing reduced Bd load up to 100%, leading to infection clearance. Conversely, the drop in Bd load with sloughing was only temporary in the more susceptible species. These findings indicate that the ability of sloughing to act as an effective immune defence is species specific, and they have implications for understanding the pattern of Bd population growth on individual hosts, as well as population-level effects.
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Affiliation(s)
- Michel E B Ohmer
- The University of Queensland, School of Biological Sciences, St. Lucia, QLD 4072, Australia. .,University of Pittsburgh, Department of Biological Sciences, Pittsburgh, PA, 15260, United States.
| | - Rebecca L Cramp
- The University of Queensland, School of Biological Sciences, St. Lucia, QLD 4072, Australia
| | - Catherine J M Russo
- The University of Queensland, School of Biological Sciences, St. Lucia, QLD 4072, Australia
| | - Craig R White
- Monash University, Centre for Geometric Biology, School of Biological Sciences, Monash, VIC 3800, Australia
| | - Craig E Franklin
- The University of Queensland, School of Biological Sciences, St. Lucia, QLD 4072, Australia
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48
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Papot C, Massol F, Jollivet D, Tasiemski A. Antagonistic evolution of an antibiotic and its molecular chaperone: how to maintain a vital ectosymbiosis in a highly fluctuating habitat. Sci Rep 2017; 7:1454. [PMID: 28469247 PMCID: PMC5431198 DOI: 10.1038/s41598-017-01626-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 03/30/2017] [Indexed: 12/25/2022] Open
Abstract
Evolution of antimicrobial peptides (AMPs) has been shown to be driven by recurrent duplications and balancing/positive selection in response to new or altered bacterial pathogens. We use Alvinella pompejana, the most eurythermal animal known on Earth, to decipher the selection patterns acting on AMP in an ecological rather than controlled infection approach. The preproalvinellacin multigenic family presents the uniqueness to encode a molecular chaperone (BRICHOS) together with an AMP (alvinellacin) that controls the vital ectosymbiosis of Alvinella. In stark contrast to what is observed in the context of the Red queen paradigm, we demonstrate that exhibiting a vital and highly conserved ecto-symbiosis in the face of thermal fluctuations has led to a peculiar selective trend promoting the adaptive diversification of the molecular chaperone of the AMP, but not of the AMP itself. Because BRICHOS stabilizes beta-stranded peptides, this polymorphism likely represents an eurythermal adaptation to stabilize the structure of alvinellacin, thus hinting at its efficiency to select and control the epibiosis across the range of temperatures experienced by the worm; Our results fill some knowledge gaps concerning the function of BRICHOS in invertebrates and offer perspectives for studying immune genes in an evolutionary ecological framework.
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Affiliation(s)
- Claire Papot
- University Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, SPICI group, F-59000, Lille, France
| | - François Massol
- University Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, SPICI group, F-59000, Lille, France
| | - Didier Jollivet
- AD2M, ABICE team, Université Pierre et Marie Curie-CNRS, UMR7144, Station Biologique de Roscoff, 29682, Roscoff, France
| | - Aurélie Tasiemski
- University Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, SPICI group, F-59000, Lille, France.
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49
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Casciaro B, Cappiello F, Cacciafesta M, Mangoni ML. Promising Approaches to Optimize the Biological Properties of the Antimicrobial Peptide Esculentin-1a(1-21)NH 2: Amino Acids Substitution and Conjugation to Nanoparticles. Front Chem 2017; 5:26. [PMID: 28487853 PMCID: PMC5404639 DOI: 10.3389/fchem.2017.00026] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 04/05/2017] [Indexed: 12/17/2022] Open
Abstract
Antimicrobial peptides (AMPs) represent an interesting class of molecules with expanding biological properties which make them a viable alternative for the development of future antibiotic drugs. However, for this purpose, some limitations must be overcome: (i) the poor biostability due to enzymatic degradation; (ii) the cytotoxicity at concentrations slightly higher than the therapeutic dosages; and (iii) the inefficient delivery to the target site at effective concentrations. Recently, a derivative of the frog skin AMP esculentin-1a, named esculentin-1a(1–21)NH2, [Esc(1–21): GIFSKLAGKKIKNLLISGLKG-NH2] has been found to have a potent activity against the Gram-negative bacterium Pseudomonas aeruginosa; a slightly weaker activity against Gram-positive bacteria and interesting immunomodulatory properties. With the aim to optimize the antimicrobial features of Esc(1–21) and to circumvent the limitations described above, two different approaches were followed: (i) substitutions by non-coded amino acids, i.e., α-aminoisobutyric acid or d-amino acids; and (ii) peptide conjugation to gold nanoparticles. In this mini-review, we summarized the structural and functional properties of the resulting Esc(1–21)-derived compounds. Overall, our data may assist researchers in the rational design and optimization of AMPs for the development of future drugs to fight the worldwide problem of antibiotic resistance.
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Affiliation(s)
- Bruno Casciaro
- Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of RomeRome, Italy
| | - Floriana Cappiello
- Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of RomeRome, Italy
| | - Mauro Cacciafesta
- Department of Cardiovascular, Respiratory, Nephrological, Anesthesiological and Geriatric Sciences, Sapienza University of RomeRome, Italy
| | - Maria Luisa Mangoni
- Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of RomeRome, Italy
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50
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Bletz MC, Perl RGB, Vences M. Skin microbiota differs drastically between co-occurring frogs and newts. ROYAL SOCIETY OPEN SCIENCE 2017; 4:170107. [PMID: 28484639 PMCID: PMC5414276 DOI: 10.1098/rsos.170107] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 03/07/2017] [Indexed: 05/10/2023]
Abstract
Diverse microbial assemblages inhabit amphibian skin and are known to differ among species; however, few studies have analysed these differences in systems that minimize confounding factors, such as season, location or host ecology. We used high-throughput amplicon sequencing to compare cutaneous microbiotas among two ranid frogs (Rana dalmatina, R. temporaria) and four salamandrid newts (Ichthyosaura alpestris, Lissotriton helveticus, L. vulgaris, Triturus cristatus) breeding simultaneously in two ponds near Braunschweig, Germany. We found that bacterial communities differed strongly and consistently between these two distinct amphibian clades. While frogs and newts had similar cutaneous bacterial richness, their bacterial composition strongly differed. Average Jaccard distances between frogs and newts were over 0.5, while between species within these groups distances were only 0.387 and 0.407 for frogs and newts, respectively. At the operational taxonomic unit (OTU) level, 31 taxa exhibited significantly different relative abundances between frogs and newts. This finding suggests that chemical or physical characteristics of these amphibians' mucosal environments provide highly selective conditions for bacterial colonizers. Multi-omics analyses of hosts and their microbiota as well as directed efforts to understand chemical differences in the mucosal environments (e.g. pH), and the specificities of host-produced compounds against potential colonizers will help to better understand this intriguing pattern.
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