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Thompson TP, Gilmore BF. Exploring halophilic environments as a source of new antibiotics. Crit Rev Microbiol 2024; 50:341-370. [PMID: 37079280 DOI: 10.1080/1040841x.2023.2197491] [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: 09/16/2022] [Accepted: 03/25/2023] [Indexed: 04/21/2023]
Abstract
Microbial natural products from microbes in extreme environments, including haloarchaea, and halophilic bacteria, possess a huge capacity to produce novel antibiotics. Additionally, enhanced isolation techniques and improved tools for genomic mining have expanded the efficiencies in the antibiotic discovery process. This review article provides a detailed overview of known antimicrobial compounds produced by halophiles from all three domains of life. We summarize that while halophilic bacteria, in particular actinomycetes, contribute the vast majority of these compounds the importance of understudied halophiles from other domains of life requires additional consideration. Finally, we conclude by discussing upcoming technologies- enhanced isolation and metagenomic screening, as tools that will be required to overcome the barriers to antimicrobial drug discovery. This review highlights the potential of these microbes from extreme environments, and their importance to the wider scientific community, with the hope of provoking discussion and collaborations within halophile biodiscovery. Importantly, we emphasize the importance of bioprospecting from communities of lesser-studied halophilic and halotolerant microorganisms as sources of novel therapeutically relevant chemical diversity to combat the high rediscovery rates. The complexity of halophiles will necessitate a multitude of scientific disciplines to unravel their potential and therefore this review reflects these research communities.
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Affiliation(s)
- Thomas P Thompson
- Biofilm Research Group, School of Pharmacy, Queen's University Belfast, Belfast, UK
| | - Brendan F Gilmore
- Biofilm Research Group, School of Pharmacy, Queen's University Belfast, Belfast, UK
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2
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Chen S, Dai Y, Ke J, Luo Y, Wang C, Hao Y, Zhang A, Han J, Xiang H. Halocin H4 is activated through cleavage by halolysin HlyR4. Appl Environ Microbiol 2024; 90:e0228423. [PMID: 38445904 PMCID: PMC11022586 DOI: 10.1128/aem.02284-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 02/19/2024] [Indexed: 03/07/2024] Open
Abstract
Halocins are antimicrobial peptides secreted by haloarchaea capable of inhibiting the growth of other haloarchaea or bacteria. Halocin H4 (HalH4) is secreted by the model halophilic archaeon Haloferax mediterranei ATCC 33500. Despite attempts to express halH4 heterologously in Escherichia coli and subsequent careful renaturation procedures commonly employed for haloarchaeal proteins, no active halocin was obtained. However, it was discovered that the antihaloarchaeal activity of this halocin could be activated through cleavage by halolysin R4 (HlyR4), a serine protease also secreted by Hfx. mediterranei ATCC 33500. Replacement of the cysteine at the number 115 amino acid with glycine and deletion of the internal trans-membrane region (15 aa) markedly abolished HalH4's antihaloarchaeal activity. Compared to the N-terminus, the C-terminal amino acid sequence was found to be more crucial for HalH4 to exert its antihaloarchaeal activity. Mass spectrometry analysis revealed that the biologically active antihaloarchaeal peptide produced after hydrolytic cleavage by HlyR4 was the C-terminus of HalH4, suggesting a potential mechanism of action involving pore formation within competitor species' cell membranes. Taken together, this study offers novel insights into the interplay between halocins and secreted proteases, as well as their contribution to antagonistic interaction within haloarchaea. IMPORTANCE The antihaloarchaeal function of halocin H4 (HalH4) can be activated by extracellular proteases from haloarchaea, as demonstrated in this study. Notably, we report the first instance of halocin activation through proteolytic cleavage, highlighting its significance in the field. The C-terminus of HalH4 (CTH4) has been identified as the antihaloarchaeal peptide present in hydrolysates generated by HlyR4. The CTH4 exhibited inhibitory activity against a range of haloarchaeal species (Haloarchaeobius spp., Haloarcula spp., Haloferax spp., Halorubellus spp., and Halorubrum spp.), as well as selected bacterial species (Aliifodinibius spp. and Salicola spp.), indicating its broad-spectrum inhibitory potential across domains. The encoding gene of halocin HalH4, halH4, from the model halophilic archaeon Haloferax mediterranei ATCC 33500 can be expressed in Escherichia coli without codon optimization.
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Affiliation(s)
- Shaoxing Chen
- College of Life Sciences, Anhui Normal University, Wuhu, China
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Yongpei Dai
- College of Life Sciences, Anhui Normal University, Wuhu, China
| | - Juntao Ke
- College of Life Sciences, Anhui Normal University, Wuhu, China
| | - Yuqing Luo
- College of Life Sciences, Anhui Normal University, Wuhu, China
| | - Chuangming Wang
- College of Biological and Agricultural Sciences, Honghe University, Mengzi, China
| | - Yuling Hao
- College of Life Sciences, Anhui Normal University, Wuhu, China
| | - Aodi Zhang
- College of Life Sciences, Anhui Normal University, Wuhu, China
| | - Jing Han
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Hua Xiang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Life Science, University of Chinese Academy of Sciences, Beijing, China
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Lach J, Krupińska M, Mikołajczyk A, Strapagiel D, Stączek P, Matera-Witkiewicz A. Novel Antimicrobial Peptides from Saline Environments Active against E. faecalis and S. aureus: Identification, Characterisation and Potential Usage. Int J Mol Sci 2023; 24:11787. [PMID: 37511545 PMCID: PMC10380286 DOI: 10.3390/ijms241411787] [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] [Received: 06/08/2023] [Revised: 07/16/2023] [Accepted: 07/19/2023] [Indexed: 07/30/2023] Open
Abstract
Microorganisms inhabiting saline environments have been known for decades as producers of many valuable bioproducts. These substances include antimicrobial peptides (AMPs), the most recognizable of which are halocins produced by halophilic Archaea. As agents with a different modes of action from that of most conventionally used antibiotics, usually associated with an increase in the permeability of the cell membrane as a result of a formation of channels and pores, AMPs are a currently promising object of research focused on the investigation of antibiotics with non-standard modes of action. The aim of this study was to investigate antimicrobial activity against multidrug-resistant human pathogens of three peptides, which were synthetised based on sequences identified in metagenomes from saline environments. The investigations were performed against Enterococcus faecalis, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Escherichia coli and Candida albicans. Subsequently, the cytotoxicity and haemolytic properties of the tested peptides were verified. An in silico analysis of the interaction of the tested peptides with molecular targets for reference antibiotics was also carried out in order to verify whether or not they can act in a similar way. The P1 peptide manifested the growth inhibition of E. faecalis at a MIC50 of 32 µg/mL and the P3 peptide at a MIC50 of 32 µg/mL was shown to inhibit the growth of both E. faecalis and S. aureus. Furthermore, the P1 and P3 peptides were shown to have no cytotoxic or haemolytic activity against human cells.
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Affiliation(s)
- Jakub Lach
- Department of Molecular Microbiology, Faculty of Biology and Environmental Protection, University of Lodz, 90-237 Lodz, Poland
- Biobank Lab, Department of Oncobiology and Epigenetics, Faculty of Biology and Environmental Protection, University of Lodz, 90-235 Lodz, Poland
| | - Magdalena Krupińska
- Screening of Biological Activity Assays and Collection of Biological Material Laboratory, Wroclaw Medical University Biobank, Faculty of Pharmacy, Wroclaw Medical University, 50-556 Wroclaw, Poland
| | - Aleksandra Mikołajczyk
- Screening of Biological Activity Assays and Collection of Biological Material Laboratory, Wroclaw Medical University Biobank, Faculty of Pharmacy, Wroclaw Medical University, 50-556 Wroclaw, Poland
| | - Dominik Strapagiel
- Biobank Lab, Department of Oncobiology and Epigenetics, Faculty of Biology and Environmental Protection, University of Lodz, 90-235 Lodz, Poland
| | - Paweł Stączek
- Department of Molecular Microbiology, Faculty of Biology and Environmental Protection, University of Lodz, 90-237 Lodz, Poland
| | - Agnieszka Matera-Witkiewicz
- Screening of Biological Activity Assays and Collection of Biological Material Laboratory, Wroclaw Medical University Biobank, Faculty of Pharmacy, Wroclaw Medical University, 50-556 Wroclaw, Poland
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4
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Liang H, Song ZM, Zhong Z, Zhang D, Yang W, Zhou L, Older EA, Li J, Wang H, Zeng Z, Li YX. Genomic and metabolic analyses reveal antagonistic lanthipeptides in archaea. MICROBIOME 2023; 11:74. [PMID: 37060102 PMCID: PMC10105419 DOI: 10.1186/s40168-023-01521-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 03/16/2023] [Indexed: 05/12/2023]
Abstract
BACKGROUND Microbes produce diverse secondary metabolites (SMs) such as signaling molecules and antimicrobials that mediate microbe-microbe interaction. Archaea, the third domain of life, are a large and diverse group of microbes that not only exist in extreme environments but are abundantly distributed throughout nature. However, our understanding of archaeal SMs lags far behind our knowledge of those in bacteria and eukarya. RESULTS Guided by genomic and metabolic analysis of archaeal SMs, we discovered two new lanthipeptides with distinct ring topologies from a halophilic archaeon of class Haloarchaea. Of these two lanthipeptides, archalan α exhibited anti-archaeal activities against halophilic archaea, potentially mediating the archaeal antagonistic interactions in the halophilic niche. To our best knowledge, archalan α represents the first lantibiotic and the first anti-archaeal SM from the archaea domain. CONCLUSIONS Our study investigates the biosynthetic potential of lanthipeptides in archaea, linking lanthipeptides to antagonistic interaction via genomic and metabolic analyses and bioassay. The discovery of these archaeal lanthipeptides is expected to stimulate the experimental study of poorly characterized archaeal chemical biology and highlight the potential of archaea as a new source of bioactive SMs. Video Abstract.
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Affiliation(s)
- Haoyu Liang
- Department of Chemistry and The Swire Institute of Marine Science, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Zhi-Man Song
- Department of Chemistry and The Swire Institute of Marine Science, The University of Hong Kong, Pokfulam Road, Hong Kong, China
- Chemistry and Chemical Engineering Guangdong Laboratory, Shantou, 515031, China
| | - Zheng Zhong
- Department of Chemistry and The Swire Institute of Marine Science, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Dengwei Zhang
- Department of Chemistry and The Swire Institute of Marine Science, The University of Hong Kong, Pokfulam Road, Hong Kong, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Wei Yang
- Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Le Zhou
- Department of Chemistry and The Swire Institute of Marine Science, The University of Hong Kong, Pokfulam Road, Hong Kong, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Ethan A Older
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, USA
| | - Jie Li
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, USA
| | - Huan Wang
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center of Nanjing University, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Zhirui Zeng
- Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China.
| | - Yong-Xin Li
- Department of Chemistry and The Swire Institute of Marine Science, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China.
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Moopantakath J, Imchen M, Anju VT, Busi S, Dyavaiah M, Martínez-Espinosa RM, Kumavath R. Bioactive molecules from haloarchaea: Scope and prospects for industrial and therapeutic applications. Front Microbiol 2023; 14:1113540. [PMID: 37065149 PMCID: PMC10102575 DOI: 10.3389/fmicb.2023.1113540] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 03/14/2023] [Indexed: 04/03/2023] Open
Abstract
Marine environments and salty inland ecosystems encompass various environmental conditions, such as extremes of temperature, salinity, pH, pressure, altitude, dry conditions, and nutrient scarcity. The extremely halophilic archaea (also called haloarchaea) are a group of microorganisms requiring high salt concentrations (2–6 M NaCl) for optimal growth. Haloarchaea have different metabolic adaptations to withstand these extreme conditions. Among the adaptations, several vesicles, granules, primary and secondary metabolites are produced that are highly significant in biotechnology, such as carotenoids, halocins, enzymes, and granules of polyhydroxyalkanoates (PHAs). Among halophilic enzymes, reductases play a significant role in the textile industry and the degradation of hydrocarbon compounds. Enzymes like dehydrogenases, glycosyl hydrolases, lipases, esterases, and proteases can also be used in several industrial procedures. More recently, several studies stated that carotenoids, gas vacuoles, and liposomes produced by haloarchaea have specific applications in medicine and pharmacy. Additionally, the production of biodegradable and biocompatible polymers by haloarchaea to store carbon makes them potent candidates to be used as cell factories in the industrial production of bioplastics. Furthermore, some haloarchaeal species can synthesize nanoparticles during heavy metal detoxification, thus shedding light on a new approach to producing nanoparticles on a large scale. Recent studies also highlight that exopolysaccharides from haloarchaea can bind the SARS-CoV-2 spike protein. This review explores the potential of haloarchaea in the industry and biotechnology as cellular factories to upscale the production of diverse bioactive compounds.
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Affiliation(s)
- Jamseel Moopantakath
- Department of Genomic Science, School of Biological Sciences, Central University of Kerala, Kerala, India
| | - Madangchanok Imchen
- Department of Microbiology, School of Life Sciences, Pondicherry University, Puducherry, India
| | - V. T. Anju
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Siddhardha Busi
- Department of Microbiology, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Madhu Dyavaiah
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Rosa María Martínez-Espinosa
- Biochemistry, Molecular Biology, Edaphology and Agricultural Chemistry Department, Faculty of Sciences, University of Alicante, Alicante, Spain
- Multidisciplinary Institute for Environmental Studies “Ramón Margalef”, University of Alicante, Alicante, Spain
- Rosa María Martínez-Espinosa,
| | - Ranjith Kumavath
- Department of Genomic Science, School of Biological Sciences, Central University of Kerala, Kerala, India
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Puducherry, India
- *Correspondence: Ranjith Kumavath, ,
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6
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Baati H, Siala M, Azri C, Ammar E, Trigui M. Hydrolytic enzyme screening and carotenoid production evaluation of halophilic archaea isolated from highly heavy metal-enriched solar saltern sediments. Braz J Microbiol 2022; 53:1893-1906. [PMID: 36280648 PMCID: PMC9679124 DOI: 10.1007/s42770-022-00855-6] [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: 06/17/2022] [Accepted: 10/14/2022] [Indexed: 01/13/2023] Open
Abstract
This paper aimed to screen the enzymatic activities and evaluate the carotenoid production level of twenty-two halophilic archaea isolated from Sfax solar saltern sediments. The molecular identification performed by sequencing the 16S rRNA genes showed that all strains have a high similarity degree (99.7-100%) with Halobacterium salinarum NRC-1. The strains were screened for the presence of eight hydrolase activities using agar plate-based assays. The most detected enzyme was gelatinase (77.27% of total strains), followed by protease (63.63%) and amylase activities (50%). The carotenoid production yields of the strains ranged between 2.027 and 14.880 mg/l. The UV-Visible spectroscopy of pigments revealed that it was a bacterioruberin type. When evaluated and compared to the standard β-carotene, the antioxidant capacities of these pigments showed a scavenging activity of more than 75% at a concentration of 5 μg/ml for three strains (AS16, AS17, and AS18). Then a sequence of one-step optimization processes was performed, using the one-factor-at-a-time approach, to define the optimum conditions for growth and carotenoid production of the highest carotenoid producing strain (AS17). Different environmental factors and nutritional conditions were tested. Variations in these factors were found to deeply influence growth and carotenoid production. A maximum carotenoid production (16.490 mg/l), higher than that of the control (14.880 mg/l), was observed at 37 °C, pH 7, 250 g/l of salinity, with 80% air phase in the flask at 110 rpm, in presence of light and in culture media containing (g/l) 10, yeast extract; 7.5, casamino acid; 20, MgSO4; 4, KCl; and 3, trisodium citrate.
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Affiliation(s)
- Houda Baati
- Research Laboratory of Environmental Sciences and Sustainable Development "LASED", University of Sfax, LR18ES32, Sfax, Tunisia.
| | - Mariem Siala
- Research Laboratory of Environmental Sciences and Sustainable Development "LASED", University of Sfax, LR18ES32, Sfax, Tunisia
| | - Chafai Azri
- Research Laboratory of Environmental Sciences and Sustainable Development "LASED", University of Sfax, LR18ES32, Sfax, Tunisia
| | - Emna Ammar
- Research Laboratory of Environmental Sciences and Sustainable Development "LASED", University of Sfax, LR18ES32, Sfax, Tunisia
| | - Mohamed Trigui
- Research Laboratory of Environmental Sciences and Sustainable Development "LASED", University of Sfax, LR18ES32, Sfax, Tunisia
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7
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Rosselli R, López-Pérez M, Martin-Cuadrado AB, Rodriguez-Valera F, Bolhuis H. Differences in gene expression patterns between cultured and natural Haloquadratum walsbyi ecotypes. Front Microbiol 2022; 13:1044446. [PMID: 36439805 PMCID: PMC9684190 DOI: 10.3389/fmicb.2022.1044446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 10/25/2022] [Indexed: 09/11/2024] Open
Abstract
Solar crystallizer ponds are characterized by high population density with a relatively simple community structure in terms of species composition. The microbial community in the solar saltern of Santa Pola (Alicante, Spain), is largely dominated by the hyperhalophilic square archaeon Haloquadratum walsbyi. Here we studied metatranscriptomes retrieved from a crystallizer pond during the winter of 2012 and summer of 2014 and compared Hqr. walsbyi's transcription patterns with that of the cultured strain Hqr. walsbyi HBSQ001. Significant differences were found between natural and the cultured grown strain in the distribution of transcript levels per gene. This likely reflects the adaptation of the cultured strain to the relative homogeneous growth conditions while the natural species, which is represented by multiple ecotypes, is adapted to heterogeneous environmental conditions and challenges of nutrient competition, viral attack, and other stressors. An important consequence of this study is that expression patterns obtained under artificial cultivation conditions cannot be directly extrapolated to gene expression under natural conditions. Moreover, we found 195 significantly differential expressed genes between the seasons, with 140 genes being higher expressed in winter and mainly encode proteins involved in energy and carbon source acquiring processes, and in stress responses.
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Affiliation(s)
- Riccardo Rosselli
- Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research (NIOZ), Den Hoorn, Netherlands
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
- LABAQUA S.A., Research & Development Department, Las Atalayas, Alicante, Spain
| | - Mario López-Pérez
- Evolutionary Genomics Group, División de Microbiología, Universidad Miguel Hernández, San Juan de Alicante, Spain
| | - Ana-Belen Martin-Cuadrado
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
- Evolutionary Genomics Group, División de Microbiología, Universidad Miguel Hernández, San Juan de Alicante, Spain
| | - Francisco Rodriguez-Valera
- LABAQUA S.A., Research & Development Department, Las Atalayas, Alicante, Spain
- Evolutionary Genomics Group, División de Microbiología, Universidad Miguel Hernández, San Juan de Alicante, Spain
| | - Henk Bolhuis
- Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research (NIOZ), Den Hoorn, Netherlands
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8
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Recent Antimicrobial Responses of Halophilic Microbes in Clinical Pathogens. Microorganisms 2022; 10:microorganisms10020417. [PMID: 35208871 PMCID: PMC8874722 DOI: 10.3390/microorganisms10020417] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 02/07/2022] [Accepted: 02/08/2022] [Indexed: 01/27/2023] Open
Abstract
Microbial pathogens that cause severe infections and are resistant to drugs are simultaneously becoming more active. This urgently calls for novel effective antibiotics. Organisms from extreme environments are known to synthesize novel bioprospecting molecules for biomedical applications due to their peculiar characteristics of growth and physiological conditions. Antimicrobial developments from hypersaline environments, such as lagoons, estuaries, and salterns, accommodate several halophilic microbes. Salinity is a distinctive environmental factor that continuously promotes the metabolic adaptation and flexibility of halophilic microbes for their survival at minimum nutritional requirements. A genetic adaptation to extreme solar radiation, ionic strength, and desiccation makes them promising candidates for drug discovery. More microbiota identified via sequencing and ‘omics’ approaches signify the hypersaline environments where compounds are produced. Microbial genera such as Bacillus, Actinobacteria, Halorubrum and Aspergillus are producing a substantial number of antimicrobial compounds. Several strategies were applied for producing novel antimicrobials from halophiles including a consortia approach. Promising results indicate that halophilic microbes can be utilised as prolific sources of bioactive metabolites with pharmaceutical potentialto expand natural product research towards diverse phylogenetic microbial groups which inhabit salterns. The present study reviews interesting antimicrobial compounds retrieved from microbial sources of various saltern environments, with a discussion of their potency in providing novel drugs against clinically drug-resistant microbes.
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9
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Rani A, Saini KC, Bast F, Varjani S, Mehariya S, Bhatia SK, Sharma N, Funk C. A Review on Microbial Products and Their Perspective Application as Antimicrobial Agents. Biomolecules 2021; 11:biom11121860. [PMID: 34944505 PMCID: PMC8699383 DOI: 10.3390/biom11121860] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Revised: 12/06/2021] [Accepted: 12/07/2021] [Indexed: 02/06/2023] Open
Abstract
Microorganisms including actinomycetes, archaea, bacteria, fungi, yeast, and microalgae are an auspicious source of vital bioactive compounds. In this review, the existing research regarding antimicrobial molecules from microorganisms is summarized. The potential antimicrobial compounds from actinomycetes, particularly Streptomyces spp.; archaea; fungi including endophytic, filamentous, and marine-derived fungi, mushroom; and microalgae are briefly described. Furthermore, this review briefly summarizes bacteriocins, halocins, sulfolobicin, etc., that target multiple-drug resistant pathogens and considers next-generation antibiotics. This review highlights the possibility of using microorganisms as an antimicrobial resource for biotechnological, nutraceutical, and pharmaceutical applications. However, more investigations are required to isolate, separate, purify, and characterize these bioactive compounds and transfer these primary drugs into clinically approved antibiotics.
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Affiliation(s)
- Alka Rani
- Department of Botany, School of Basic and Applied Sciences, Central University of Punjab, Bathinda 151401, India; (A.R.); (K.C.S.)
| | - Khem Chand Saini
- Department of Botany, School of Basic and Applied Sciences, Central University of Punjab, Bathinda 151401, India; (A.R.); (K.C.S.)
| | - Felix Bast
- Department of Botany, School of Basic and Applied Sciences, Central University of Punjab, Bathinda 151401, India; (A.R.); (K.C.S.)
- Correspondence: (F.B.); (S.M.); (S.K.B.)
| | - Sunita Varjani
- Gujarat Pollution Control Board, Gandhinagar 382010, India;
| | - Sanjeet Mehariya
- Department of Chemistry, Umeå University, 90187 Umeå, Sweden;
- Correspondence: (F.B.); (S.M.); (S.K.B.)
| | - Shashi Kant Bhatia
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Korea
- Correspondence: (F.B.); (S.M.); (S.K.B.)
| | - Neeta Sharma
- ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Department of Sustainability-CR Trisaia, SS Jonica 106, km 419 + 500, 75026 Rotondella, Italy;
| | - Christiane Funk
- Department of Chemistry, Umeå University, 90187 Umeå, Sweden;
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10
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Kumar V, Singh B, van Belkum MJ, Diep DB, Chikindas ML, Ermakov AM, Tiwari SK. Halocins, natural antimicrobials of Archaea: Exotic or special or both? Biotechnol Adv 2021; 53:107834. [PMID: 34509601 DOI: 10.1016/j.biotechadv.2021.107834] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 08/31/2021] [Accepted: 09/06/2021] [Indexed: 01/16/2023]
Abstract
Haloarchaea are adapted to survive under extreme saline conditions by accumulating osmolytes and salts to counteract the high osmotic pressure in their habitats. As a consequence, their proteins have evolved to remain active, or even most active, at very high ionic strength. Halocins are proteinaceous antimicrobial substances that are ribosomally-synthesized by haloarchaea and they provide the producers an advantage in the competition for nutrients and ecological niches. These antimicrobials are stable at high temperature, elevated salt concentrations, and alkaline pH conditions. These properties have endowed them with great potential in diverse biotechnological applications, which involve extreme processing conditions (such as high salt concentrations, high pressure, or high temperatures). They kill target cells by inhibition of Na+/H+ antiporter in the membrane or modification/disruption of the cell membrane leading to cell lysis. In general, the taxonomy of haloarchaea and their typical phenotypic and genotypic characteristics are well studied; however, information regarding their halocins, especially aspects related to genetics, biosynthetic pathways, mechanism of action, and structure-function relationship is very limited. A few studies have demonstrated the potential applications of halocins in the preservation of salted food products and brine-cured hides in leather industries, protecting the myocardium from ischemia and reperfusion injury, as well as from life-threatening diseases such as cardiac arrest and cancers. In recent years, genome mining has been an essential tool to decipher the genetic basis of halocin biosynthesis. Nevertheless, this is likely the tip of the iceberg as genome analyses have revealed many putative halocins in databases waiting for further investigation. Identification and characterization of this source of halocins may lead to antimicrobials for future therapeutics and/or food preservation. Hence, the present review analyzes different aspects of halocins such as biosynthesis, mechanism of action against target cells, and potential biotechnological applications.
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Affiliation(s)
- Vijay Kumar
- Department of Genetics, Maharshi Dayanand University, Rohtak 124001, Haryana, India; Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Bijender Singh
- Department of Biotechnology, Central University of Haryana, Jant-Pali 123031, Mahendergarh, Haryana, India; Department of Microbiology, Maharshi Dayanand University, Rohtak 124001, Haryana, India
| | - Marco J van Belkum
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Dzung B Diep
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås 1430, Norway
| | - Michael L Chikindas
- Health Promoting Naturals Laboratory, School of Environmental and Biological Sciences, Rutgers, the State University of New Jersey, New Brunswick, New Jersey 08901, USA; Center for Agrobiotechnology, Don State Technical University, Rostov-on-Don 344002, Russia; I. M. Sechenov First Moscow State Medical University, Moscow 119435, Russia
| | - Alexey M Ermakov
- I. M. Sechenov First Moscow State Medical University, Moscow 119435, Russia
| | - Santosh Kumar Tiwari
- Department of Genetics, Maharshi Dayanand University, Rohtak 124001, Haryana, India.
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11
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Kaur R, Tiwari SK. Purification and Characterization of a New Halocin HA4 from Haloferax larsenii HA4 Isolated from a Salt Lake. Probiotics Antimicrob Proteins 2021; 13:1458-1466. [PMID: 34286419 DOI: 10.1007/s12602-021-09823-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/08/2021] [Indexed: 11/30/2022]
Abstract
Halocins are antimicrobial peptides secreted by different members of haloarchaea. Halocin HA4 was purified from Haloferax larsenii HA4 using combination of ultrafiltration and chromatographic techniques. It was found to be ~ 14 kDa with unique N-terminal sequence, H2N-AEEEIFXPDX, which did not show homology with the known sequence suggesting a new/novel compound. It was found to be heat resistant up to 100 °C, stable at pH 2.0-10.0, and retained complete activity in the presence of different organic compounds such as methanol, ethanol, acetone, isopropanol, ethyl acetate, Tween 80, acetonitrile, SDS, Triton X-100, and urea. However, complete activity was reduced after the treatment with trypsin, papain, and proteinase K suggesting proteinaceous nature of the compound. The cytocidal nature of halocin HA4 was evidenced with complete loss of viable count of indicator strain, H. larsenii HA10. The change in FTIR spectrum of halocin-treated cells suggested halocin HA4 interacts with cell membrane and nucleic acids of the target cells. Thus, we report a new halocin inhibitory to related strains and may be applied in the preservation of salted foods and leather hides in the respective industries.
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Affiliation(s)
- Ramanjeet Kaur
- Department of Genetics, Maharshi Dayanand University, Rohtak, 124001, Haryana, India
| | - Santosh Kumar Tiwari
- Department of Genetics, Maharshi Dayanand University, Rohtak, 124001, Haryana, India.
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12
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Identification of Multi-Potent Protein Subtilisin A from halophilic bacterium Bacillus firmus VE2. Microb Pathog 2021; 157:105007. [PMID: 34044052 DOI: 10.1016/j.micpath.2021.105007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 05/19/2021] [Accepted: 05/20/2021] [Indexed: 11/23/2022]
Abstract
Screening of halophiles with antimicrobial activity in saltpan soil samples from Nagapattinam district, Tamil Nadu, revealed isolate VE-2 as the most potent, identified as Bacillus firmus strain VE-2 through 16s rRNA gene sequencing. It had an optimum growth condition (OD 3.1) and antimicrobial protein (AMP) production (450 μg/mL) at 37 °C, pH 8, 25% NaCl, and 36 h incubation. SDS-PAGE analysis of the purified AMP showed the molecular weight of 36 kDa. HPLC analysis of the purified AMP showed different amino acids, such as asparagines, alanine, lysine, proline, threonine, glycine, cysteine, serine, aspartic acid leucine, and valine. Further characterization and identification using FT-IR, 2D-PAGE, MALDI-TOF, and in-silico analysis showed that the isolated AMP had the highest similarity to Subtilisin-A. It showed antibacterial activity against clinical bacterial pathogens like S. aureus, S. pyogenes, C. diphtheria, E. coli, and P. aeruginosa with the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration of 2.5 μg/mL and 20 μg/mL and also against various fungal pathogens such as A. niger, A. flavus, C. albicans, C. tropicalis and C. parapsilosis with the MIC and minimum fungicidal concentrations of 1.25-80 μg/mL. The purified AMP had excellent antioxidant potential, showed a scavenging effect against DPPH and Nitric oxide radicals, and displayed anticancer activity against HeLa cell lines with the IC50 values 53 μg/mL. Hence, the purified bioactive antimicrobial peptides (AMP) could also be used in anticancer therapies.
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13
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Kaur R, Tiwari SK. Identification and characterization of a halocin-producing haloarchaeon isolated from Pachpadra salt lake. Lett Appl Microbiol 2020; 71:620-626. [PMID: 32844475 DOI: 10.1111/lam.13377] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/15/2020] [Accepted: 08/15/2020] [Indexed: 01/06/2023]
Abstract
Haloarchaea are known to produce antimicrobial proteins, halocins which are generally stable at extreme conditions suggesting their potential biotechnological applications. Here, we report a halocin-producing haloarchaeon isolated from salt lake and identified as Haloferax larsenii HA4 using partial 16S rDNA sequence and biochemical properties. Whole-cell methanolysate showed ether-linked lipids, which is a characteristic feature of haloarchaea. Strain HA4 was able to grow at pH 6·0-10·0 and 15-30% NaCl. The growth response was normal but antimicrobial activity was detected only during the log-phase. Crude halocin HA4 was active in the pH range of pH 2·0-10·0 with stability up to 100°C. Cell-free supernatant (CFS) was also stable in different organic solvents and detergents tested. However, halocin activity was reduced after treatment with proteinase K suggesting the proteinaceous nature of the active compound. Concentrated CFS showed the presence of several proteins from 6·5-66 kDa but bioassay suggested ~14 kDa protein as halocin. Crude halocin preparation showed cytocidal activity against indicator strain, H. larsenii HA10 and inhibited the growth of other related strains such as H. larsenii HA3, HA8, HA9 and HA10.
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Affiliation(s)
- R Kaur
- Department of Genetics, Maharshi Dayanand University, Rohtak, Haryana, India
| | - S K Tiwari
- Department of Genetics, Maharshi Dayanand University, Rohtak, Haryana, India
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14
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Ghanmi F, Carré-Mlouka A, Zarai Z, Mejdoub H, Peduzzi J, Maalej S, Rebuffat S. The extremely halophilic archaeon Halobacterium salinarum ETD5 from the solar saltern of Sfax (Tunisia) produces multiple halocins. Res Microbiol 2019; 171:80-90. [PMID: 31560985 DOI: 10.1016/j.resmic.2019.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 07/09/2019] [Accepted: 09/17/2019] [Indexed: 10/26/2022]
Abstract
The extremely halophilic archaeon Halobacterium salinarum strain ETD5 was previously isolated from the solar saltern of Sfax (Tunisia) and shown to encode and express halocin S8. The Hbt. salinarum ETD5 culture supernatant was shown here to exhibit high antimicrobial activity against several halophilic archaea and bacteria of different genera, showing a cross-domain inhibition. The antimicrobial activity was destroyed by proteases, thus pointing to halocins. A bioguided purification procedure was applied using two chromatography steps and antimicrobial assays directed against Halorubrum chaoviator ETR14. In-gel screening assay showed the presence of two antimicrobial bands of approximately 8 and 14 kDa, for which characterization was investigated by N-terminal sequencing and mass spectrometry. The full-length form of halocin S8 that contains 81 amino acids and differs from the 36 amino acid short-length halocin S8 previously described from an uncharacterized haloarchaeon S8a, was identified in the 8 kDa halocin band. A novel halocin that we termed halocin S14 was found in the 14 kDa band. It exhibits amino acid sequence identities with the N-terminally truncated region of the archaeal Mn-superoxide dismutase. These results show that Hbt. salinarum ETD5 produces multiple halocins, a feature that had not been described until now in the domain Archaea.
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Affiliation(s)
- Fadoua Ghanmi
- Laboratory Molecules of Communication and Adaptation of Microorganisms (MCAM) UMR 7245 CNRS-MNHN, Muséum national d'Histoire naturelle, Centre national de la Recherche scientifique (CNRS), CP 54, 57 rue Cuvier, 75005, Paris, France; Laboratory of Biodiversity and Aquatic Ecosystems, Ecology and Planktonology, University of Sfax-Tunisia, Faculty of Sciences, BP 1171, Tunisia.
| | - Alyssa Carré-Mlouka
- Laboratory Molecules of Communication and Adaptation of Microorganisms (MCAM) UMR 7245 CNRS-MNHN, Muséum national d'Histoire naturelle, Centre national de la Recherche scientifique (CNRS), CP 54, 57 rue Cuvier, 75005, Paris, France.
| | - Zied Zarai
- Laboratory of Plant Biotechnology, Sfax Faculty of Sciences, University of Sfax-Tunisia, Faculty of Sciences, BP 1171, Tunisia.
| | - Hafedh Mejdoub
- Laboratory of Plant Biotechnology, Sfax Faculty of Sciences, University of Sfax-Tunisia, Faculty of Sciences, BP 1171, Tunisia.
| | - Jean Peduzzi
- Laboratory Molecules of Communication and Adaptation of Microorganisms (MCAM) UMR 7245 CNRS-MNHN, Muséum national d'Histoire naturelle, Centre national de la Recherche scientifique (CNRS), CP 54, 57 rue Cuvier, 75005, Paris, France.
| | - Sami Maalej
- Laboratory of Biodiversity and Aquatic Ecosystems, Ecology and Planktonology, University of Sfax-Tunisia, Faculty of Sciences, BP 1171, Tunisia.
| | - Sylvie Rebuffat
- Laboratory Molecules of Communication and Adaptation of Microorganisms (MCAM) UMR 7245 CNRS-MNHN, Muséum national d'Histoire naturelle, Centre national de la Recherche scientifique (CNRS), CP 54, 57 rue Cuvier, 75005, Paris, France.
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Chen S, Sun S, Korfanty GA, Liu J, Xiang H. A Halocin Promotes DNA Uptake in Haloferax mediterranei. Front Microbiol 2019; 10:1960. [PMID: 31620096 PMCID: PMC6759562 DOI: 10.3389/fmicb.2019.01960] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 08/09/2019] [Indexed: 11/13/2022] Open
Abstract
Halocins are antimicrobial peptides or proteins that are produced by halophilic archaea. Although their function in inhibiting the growth of closely related haloarchaeal strains is well known, other physiological functions of halocins have also been proposed in recent years. To unveil the possible function and mechanism of halocins in DNA uptake, the halocin H4 producing strain Haloferax mediterranei DF50-ΔEPS (incapable of EPS production) was used in this study. We found that deletion of the halH4 resulted in the strain DF50-ΔEPSΔhalH4 which exhibited loss of natural DNA uptake ability. Moreover, supernatants of the halocin producing strain were capable of inducing the ability to uptake DNA. Obviously, halocin is likely responsible for inducing DNA uptake. Cell surface ultrastructures of these strains are varied from strains DF50-ΔEPS to DF50-ΔEPSΔhalH4. The cell surface of strain DF50-ΔEPS is rough due to numerous pinholes, while that of the strain DF50-ΔEPSΔhalH4 is smooth without visible pinholes. The morphology of the halH4 complemented strain, DF50-ΔEPSΔhalH4::H4, shows an intermediate phenotype between strains DF50-ΔEPS and DF50-ΔEPSΔhalH4. We speculate that halocin H4 may accelerate DNA uptake by perforating the cell surface ultrastructure. The halocin H4 may represent a novel inducer or activator of DNA uptake in Hfx. mediterranei.
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Affiliation(s)
- Shaoxing Chen
- Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, College of Life Sciences, Anhui Normal University, Wuhu, China
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Siqi Sun
- Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, College of Life Sciences, Anhui Normal University, Wuhu, China
| | | | - Jingwen Liu
- Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, College of Life Sciences, Anhui Normal University, Wuhu, China
| | - Hua Xiang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
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16
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Kaur A, Capalash N, Sharma P. Communication mechanisms in extremophiles: Exploring their existence and industrial applications. Microbiol Res 2019; 221:15-27. [DOI: 10.1016/j.micres.2019.01.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 01/02/2019] [Accepted: 01/17/2019] [Indexed: 12/20/2022]
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17
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Nasfi Z, Busch H, Kehraus S, Linares-Otoya L, König GM, Schäberle TF, Bachoual R. Soil Bacteria Isolated From Tunisian Arid Areas Show Promising Antimicrobial Activities Against Gram-Negatives. Front Microbiol 2018; 9:2742. [PMID: 30483240 PMCID: PMC6242944 DOI: 10.3389/fmicb.2018.02742] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 10/26/2018] [Indexed: 12/20/2022] Open
Abstract
Arid regions show relatively fewer species in comparison to better-watered biomes, but the competition for the few nutrients is very distinct. Here, in total 373 bacterial strains were isolated from rhizospheric soils obtained from three different sampling sites in Tunisia. Their potential for the production of antimicrobial compounds was evaluated. Bacterial strains, showing antibacterial activity against pathogenic bacteria, were isolated from all three sites, one strain from the Bou-Hedma national park, 15 strains from Chott-Djerid, and 13 strains from Matmata, respectively. The dominant genus was Bacillus, with 27 out of 29 strains. Most interestingly, 93% of the isolates showed activity against Gram-positive and Gram-negative test bacteria. Strain Bacillus sp. M21, harboring high inhibitory potential, even against clinical isolates of Gram-negative bacteria, was analyzed in detail to enable purification and identification of the bioactive compound responsible for its bioactivity. Subsequent HPLC-MS and NMR analyses resulted in the identification of 1-acetyl-β-carboline as active component. Furthermore, fungicides of the bacillomycin and fengycin group, which in addition show antibiotic effects, were identified. This work highlights the high potential of the arid-adapted strains for the biosynthesis of specialized metabolites and suggest further investigation of extreme environments, since they constitute a promising bioresource of biologically active compounds.
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Affiliation(s)
- Zina Nasfi
- Laboratory of Plant Improvement and Valorization of Agroresources, National School of Engineering of Sfax, Sfax, Tunisia
- Institute for Insect Biotechnology, Justus-Liebig-University Giessen, Giessen, Germany
- Faculty of Sciences of Gabès, University of Gabès, Gabès, Tunisia
| | - Henrik Busch
- Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Stefan Kehraus
- Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Luis Linares-Otoya
- Institute for Insect Biotechnology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Gabriele M. König
- Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Till F. Schäberle
- Institute for Insect Biotechnology, Justus-Liebig-University Giessen, Giessen, Germany
- Department of Bioresources of the Fraunhofer Institute for Molecular Biology and Applied Ecology, Giessen, Germany
| | - Rafik Bachoual
- Laboratory of Plant Improvement and Valorization of Agroresources, National School of Engineering of Sfax, Sfax, Tunisia
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19
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Halocin C8: an antimicrobial peptide distributed among four halophilic archaeal genera: Natrinema, Haloterrigena, Haloferax, and Halobacterium. Extremophiles 2017; 21:623-638. [DOI: 10.1007/s00792-017-0931-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 03/24/2017] [Indexed: 11/26/2022]
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20
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Kumar V, Tiwari SK. Activity-guided separation and characterization of new halocin HA3 from fermented broth of Haloferax larsenii HA3. Extremophiles 2017; 21:609-621. [PMID: 28378299 DOI: 10.1007/s00792-017-0930-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 03/23/2017] [Indexed: 10/19/2022]
Abstract
Haloferax larsenii HA3 was able to grow optimally in HS medium containing 15% NaCl, at pH 7.2 and 42 °C in aerobic conditions. Strain HA3 was found to be round shape, Gram-negative, catalase-positive, sensitive to bile acid, and resistant to chloramphenicol, and could not utilize arginine. The lipid profile revealed the presence of glycerol diether moiety (GDEM) suggesting Haloarchaea characteristics. Phylogenetic analysis based on 16S rRNA gene sequence similarities showed that it was closely related to H. larsenii ZJ206. Interestingly, strain HA3 was found to produce halocin HA3 which was purified using ultrafiltration and chromatography. It was found to be stable up to 80 °C, pH 2.0-10.0, organic solvents, surfactants, and detergents tested. However, the activity of halocin HA3 was completely reduced in the presence of proteinase K and trypsin. It was found to be halocidal against H. larsenii HA10, rupturing cell boundary and leading to cell death. The molecular weight of halocin HA3 was found to be ~13 kDa and MALDI-TOF MS/MS analysis suggested no homology with known halocins. The N-terminal ten amino-acid residues, NH2MNLGIILETN-COOH, suggested a new/novel halocin. These properties of halocin HA3 may be applicable for control of Haloarchaea in environments and salted foods.
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Affiliation(s)
- Vijay Kumar
- Department of Genetics, Maharshi Dayanand University, Rohtak, 124001, Haryana, India
| | - Santosh Kumar Tiwari
- Department of Genetics, Maharshi Dayanand University, Rohtak, 124001, Haryana, India.
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