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Abstract
Hypersaline waters and glacial ice are inhospitable environments that have low water activity and high concentrations of osmolytes. They are inhabited by diverse microbial communities, of which extremotolerant and extremophilic fungi are essential components. Some fungi are specialized in only one of these two environments and can thrive in conditions that are lethal to most other life-forms. Others are generalists, highly adaptable species that occur in both environments and tolerate a wide range of extremes. Both groups efficiently balance cellular osmotic pressure and ion concentration, stabilize cell membranes, remodel cell walls, and neutralize intracellular oxidative stress. Some species use unusual reproductive strategies. Further investigation of these adaptations with new methods and carefully designed experiments under ecologically relevant conditions will help predict the role of fungi in hypersaline and glacial environments affected by climate change, decipher their stress resistance mechanisms and exploit their biotechnological potential.
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Affiliation(s)
- Cene Gostinčar
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia; ,
| | - Nina Gunde-Cimerman
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia; ,
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Barratclough A, Ferguson SH, Lydersen C, Thomas PO, Kovacs KM. A Review of Circumpolar Arctic Marine Mammal Health-A Call to Action in a Time of Rapid Environmental Change. Pathogens 2023; 12:937. [PMID: 37513784 PMCID: PMC10385039 DOI: 10.3390/pathogens12070937] [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: 04/13/2023] [Revised: 06/16/2023] [Accepted: 07/12/2023] [Indexed: 07/30/2023] Open
Abstract
The impacts of climate change on the health of marine mammals are increasingly being recognised. Given the rapid rate of environmental change in the Arctic, the potential ramifications on the health of marine mammals in this region are a particular concern. There are eleven endemic Arctic marine mammal species (AMMs) comprising three cetaceans, seven pinnipeds, and the polar bear (Ursus maritimus). All of these species are dependent on sea ice for survival, particularly those requiring ice for breeding. As air and water temperatures increase, additional species previously non-resident in Arctic waters are extending their ranges northward, leading to greater species overlaps and a concomitant increased risk of disease transmission. In this study, we review the literature documenting disease presence in Arctic marine mammals to understand the current causes of morbidity and mortality in these species and forecast future disease issues. Our review highlights potential pathogen occurrence in a changing Arctic environment, discussing surveillance methods for 35 specific pathogens, identifying risk factors associated with these diseases, as well as making recommendations for future monitoring for emerging pathogens. Several of the pathogens discussed have the potential to cause unusual mortality events in AMMs. Brucella, morbillivirus, influenza A virus, and Toxoplasma gondii are all of concern, particularly with the relative naivety of the immune systems of endemic Arctic species. There is a clear need for increased surveillance to understand baseline disease levels and address the gravity of the predicted impacts of climate change on marine mammal species.
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Affiliation(s)
- Ashley Barratclough
- National Marine Mammal Foundation, 2240 Shelter Island Drive, San Diego, CA 92106, USA
| | - Steven H. Ferguson
- Arctic Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, MB R3T 2N6, Canada;
| | - Christian Lydersen
- Norwegian Polar Institute, Fram Centre, 9296 Tromsø, Norway; (C.L.); (K.M.K.)
| | - Peter O. Thomas
- Marine Mammal Commission, 4340 East-West Highway, Room 700, Bethesda, MD 20814, USA;
| | - Kit M. Kovacs
- Norwegian Polar Institute, Fram Centre, 9296 Tromsø, Norway; (C.L.); (K.M.K.)
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Chen X, Yan D, Yu L, Zhang T. An Integrative Study of Mycobiome in Different Habitats from a High Arctic Region: Diversity, Distribution, and Functional Role. J Fungi (Basel) 2023; 9:jof9040437. [PMID: 37108892 PMCID: PMC10144742 DOI: 10.3390/jof9040437] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 03/24/2023] [Accepted: 03/28/2023] [Indexed: 04/07/2023] Open
Abstract
In the Arctic ecosystems, fungi are crucial for interactions between soil and plants, the cycling of nutrients, and the transport of carbon. To date, no studies have been conducted to thoroughly examine the mycobiome and its functional role in various habitats of the High Arctic region. The aim was to unravel the mycobiome in the nine habitats (i.e., soil, lichen, vascular plant, moss, freshwater, seawater, marine sediment, dung, and marine alga) in the Ny-Ålesund Region (Svalbard, High Arctic) using a high-throughput sequencing approach. A total of 10,419 ASVs were detected. Among them, 7535 ASVs were assigned to unidentified phyla, while the remaining 2884 ASVs were assigned to 11 phyla, 33 classes, 81 orders, 151 families, 278 genera, and 261 species that were known. The distribution of the mycobiome was driven by habitat specificity, indicating that habitat filtering is a crucial factor influencing the fungal assemblages at a local scale in this High Arctic region. Six growth forms and 19 fungal guilds were found. The ecological guild (e.g., lichenized, ectomycorrhizal) and growth form (e.g., yeast, thallus photosynthetic) varied significantly among various habitats. In addition, the occurrence of 31 fungal species that are considered to be potential pathogens was determined. These results will increase our understanding of fungal diversity and its functional significance in this distinctive High Arctic area and thereby establish the groundwork for prediction about how the mycobiome will alter in various environments as a result of anticipated climate change.
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Affiliation(s)
- Xiufei Chen
- China Pharmaceutical Culture Collection, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Dong Yan
- Xinxiang Key Laboratory of Pathogenic Biology, Department of Pathogenic Biology, School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang 453003, China
| | - Liyan Yu
- China Pharmaceutical Culture Collection, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Tao Zhang
- China Pharmaceutical Culture Collection, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
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Samaddar A, Sharma A. First case of neonatal fungemia caused by Aureobasidium melanogenum. J Mycol Med 2023; 33:101334. [PMID: 36270215 DOI: 10.1016/j.mycmed.2022.101334] [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] [Revised: 08/17/2022] [Accepted: 09/23/2022] [Indexed: 11/20/2022]
Abstract
Aureobasidium melanogenum is a saprophytic, dematiaceous, yeast-like fungus rarely implicated in human infections. Here, we report the first case of A. melanogenum fungemia in a 30-week-old preterm, very low birth weight neonate born to a primigravida with history of gestational diabetes, pregnancy induced hypertension and oligohydramnios. The baby developed respiratory distress, hypotension, bradycardia, coagulopathy and septic shock shortly after birth, and eventually succumbed to multiple organ dysfunction syndrome on day 9 of life. Paired blood culture showed growth of a dematiaceous yeast-like fungus which was identified as A. melanogenum by rDNA internal transcribed spacer (ITS) sequencing. Antifungal susceptibility testing of the isolate showed high minimum inhibitory concentration of fluconazole (32 µg/mL), indicating resistance. Diagnosis of A. melanogenum fungemia is difficult as it is easily confused with Candida species in Gram stained smears and similar colony morphology during the initial stages of growth. Also, the conventional diagnostic methods, such as VITEK 2 and MALDI-TOF MS are unreliable for identification of this pathogen. Accurate identification using molecular techniques is crucial for making treatment decisions as A. melanogenum shows substantial antifungal resistance. Clinicians should be aware that yeast-like cells in blood culture are not only indicative of Candida species, but also rare pathogens like A. melanogenum and should exercise caution while starting fluconazole therapy. At present, there are no established susceptibility breakpoints for Aureobasidium spp. Further studies are needed to determine the optimal treatment for such infections.
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Affiliation(s)
- Arghadip Samaddar
- Department of Microbiology, All India Institute of Medical Sciences, Jodhpur, Rajasthan, India.
| | - Anuradha Sharma
- Department of Microbiology, All India Institute of Medical Sciences, Jodhpur, Rajasthan, India
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Černoša A, Sun X, Gostinčar C, Fang C, Gunde-Cimerman N, Song Z. Virulence Traits and Population Genomics of the Black Yeast Aureobasidium melanogenum. J Fungi (Basel) 2021; 7:jof7080665. [PMID: 34436204 PMCID: PMC8401163 DOI: 10.3390/jof7080665] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 08/13/2021] [Accepted: 08/14/2021] [Indexed: 12/22/2022] Open
Abstract
The black yeast-like fungus Aureobasidium melanogenum is an opportunistic human pathogen frequently found indoors. Its traits, potentially linked to pathogenesis, have never been systematically studied. Here, we examine 49 A. melanogenum strains for growth at 37 °C, siderophore production, hemolytic activity, and assimilation of hydrocarbons and human neurotransmitters and report within-species variability. All but one strain grew at 37 °C. All strains produced siderophores and showed some hemolytic activity. The largest differences between strains were observed in the assimilation of hydrocarbons and human neurotransmitters. We show for the first time that fungi from the order Dothideales can assimilate aromatic hydrocarbons. To explain the background, we sequenced the genomes of all 49 strains and identified genes putatively involved in siderophore production and hemolysis. Genomic analysis revealed a fairly structured population of A.melanogenum, raising the possibility that some phylogenetic lineages have higher virulence potential than others. Population genomics indicated that the species is strictly clonal, although more than half of the genomes were diploid. The existence of relatively heterozygous diploids in an otherwise clonal species is described for only the second time in fungi. The genomic and phenotypic data from this study should help to resolve the non-trivial taxonomy of the genus Aureobasidium and reduce the medical hazards of exploiting the biotechnological potential of other, non-pathogenic species of this genus.
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Affiliation(s)
- Anja Černoša
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (A.Č.); (N.G.-C.)
| | - Xiaohuan Sun
- BGI-Shenzhen, Beishan Industrial Zone, Shenzhen 518083, China; (X.S.); (C.F.); (Z.S.)
| | - Cene Gostinčar
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (A.Č.); (N.G.-C.)
- Lars Bolund Institute of Regenerative Medicine, BGI-Qingdao, Qingdao 266555, China
- Correspondence: or ; Tel.: +386-1-320-3392
| | - Chao Fang
- BGI-Shenzhen, Beishan Industrial Zone, Shenzhen 518083, China; (X.S.); (C.F.); (Z.S.)
| | - Nina Gunde-Cimerman
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (A.Č.); (N.G.-C.)
| | - Zewei Song
- BGI-Shenzhen, Beishan Industrial Zone, Shenzhen 518083, China; (X.S.); (C.F.); (Z.S.)
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Mead HL, Hamm PS, Shaffer IN, Teixeira MDM, Wendel CS, Wiederhold NP, Thompson GR, Muñiz-Salazar R, Castañón-Olivares LR, Keim P, Plude C, Terriquez J, Galgiani JN, Orbach MJ, Barker BM. Differential Thermotolerance Adaptation between Species of Coccidioides. J Fungi (Basel) 2020; 6:E366. [PMID: 33327629 PMCID: PMC7765126 DOI: 10.3390/jof6040366] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 11/24/2020] [Accepted: 12/05/2020] [Indexed: 12/18/2022] Open
Abstract
Coccidioidomycosis, or Valley fever, is caused by two species of dimorphic fungi. Based on molecular phylogenetic evidence, the genus Coccidioides contains two reciprocally monophyletic species: C. immitis and C. posadasii. However, phenotypic variation between species has not been deeply investigated. We therefore explored differences in growth rate under various conditions. A collection of 39 C. posadasii and 46 C. immitis isolates, representing the full geographical range of the two species, was screened for mycelial growth rate at 37 °C and 28 °C on solid media. The radial growth rate was measured for 16 days on yeast extract agar. A linear mixed effect model was used to compare the growth rate of C. posadasii and C. immitis at 37 °C and 28 °C, respectively. C. posadasii grew significantly faster at 37 °C, when compared to C. immitis; whereas both species had similar growth rates at 28 °C. These results indicate thermotolerance differs between these two species. As the ecological niche has not been well-described for Coccidioides spp., and disease variability between species has not been shown, the evolutionary pressure underlying the adaptation is unclear. However, this research reveals the first significant phenotypic difference between the two species that directly applies to ecological research.
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Affiliation(s)
- Heather L. Mead
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ 86011, USA; (H.L.M.); (P.K.)
| | - Paris S. Hamm
- Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA;
| | - Isaac N. Shaffer
- School of Informatics, Computers, and Cyber Systems, Northern Arizona University, Flagstaff, AZ 86011, USA;
| | | | | | - Nathan P. Wiederhold
- Department of Pathology and Laboratory Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 77030, USA;
| | - George R. Thompson
- Departments of Internal Medicine Division of Infectious Diseases, and Medical Microbiology and Immunology, University of California-Davis, Sacramento, CA 95616, USA;
| | - Raquel Muñiz-Salazar
- Laboratorio de Epidemiología y Ecología Molecular, Escuela Ciencias de la Salud, Universidad Autónoma de Baja California, Unidad Valle Dorado, Ensenada 22890, Mexico;
| | - Laura Rosio Castañón-Olivares
- Department of Microbiology and Parasitology, Universidad Nacional Autónoma de Mexico, Ciudad de México 04510, Mexico;
| | - Paul Keim
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ 86011, USA; (H.L.M.); (P.K.)
| | - Carmel Plude
- Northern Arizona Healthcare, Flagstaff, AZ 86001, USA; (C.P.); (J.T.)
| | - Joel Terriquez
- Northern Arizona Healthcare, Flagstaff, AZ 86001, USA; (C.P.); (J.T.)
| | - John N. Galgiani
- Valley Fever Center for Excellence, University of Arizona, Tucson, AZ 85721, USA; (J.N.G.); (M.J.O.)
| | - Marc J. Orbach
- Valley Fever Center for Excellence, University of Arizona, Tucson, AZ 85721, USA; (J.N.G.); (M.J.O.)
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Bridget M. Barker
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ 86011, USA; (H.L.M.); (P.K.)
- Valley Fever Center for Excellence, University of Arizona, Tucson, AZ 85721, USA; (J.N.G.); (M.J.O.)
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