1
|
Hotopp AM, Olsen BJ, Ishaq SL, Frey SD, Kovach AI, Kinnison MT, Gigliotti FN, Roeder MR, Cammen KM. Plumage microorganism communities of tidal marsh sparrows. iScience 2024; 27:108668. [PMID: 38230264 PMCID: PMC10790016 DOI: 10.1016/j.isci.2023.108668] [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: 06/16/2023] [Revised: 11/02/2023] [Accepted: 12/05/2023] [Indexed: 01/18/2024] Open
Abstract
Microorganism communities can shape host phenotype evolution but are often comprised of thousands of taxa with varied impact on hosts. Identification of taxa influencing host evolution relies on first describing microorganism communities and acquisition routes. Keratinolytic (keratin-degrading) microorganisms are hypothesized to be abundant in saltmarsh sediments and to contribute to plumage evolution in saltmarsh-adapted sparrows. Metabarcoding was used to describe plumage bacterial (16S rRNA) and fungal (ITS) communities in three sparrow species endemic to North America's Atlantic coast saltmarshes. Results describe limited within-species variability and moderate host species-level patterns in microorganism diversity and community composition. A small percentage of overall microorganism diversity was comprised of potentially keratinolytic microorganisms, warranting further functional studies. Distinctions between plumage and saltmarsh sediment bacteria, but not fungal, communities were detected, suggesting multiple bacterial acquisition routes and/or vertebrate host specialization. This research lays groundwork for future testing of causal links between microorganisms and avian host evolution.
Collapse
Affiliation(s)
- Alice M. Hotopp
- School of Biology and Ecology, University of Maine, Orono, ME 04469, USA
| | - Brian J. Olsen
- School of Biology and Ecology, University of Maine, Orono, ME 04469, USA
- Maine Center for Genetics in the Environment, University of Maine, Orono, ME 04469, USA
| | - Suzanne L. Ishaq
- School of Food and Agriculture, University of Maine, Orono, ME 04469, USA
| | - Serita D. Frey
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH 03824, USA
| | - Adrienne I. Kovach
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH 03824, USA
| | - Michael T. Kinnison
- School of Biology and Ecology, University of Maine, Orono, ME 04469, USA
- Maine Center for Genetics in the Environment, University of Maine, Orono, ME 04469, USA
| | - Franco N. Gigliotti
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA
| | | | - Kristina M. Cammen
- School of Marine Sciences, University of Maine, Orono, ME 04469, USA
- Maine Center for Genetics in the Environment, University of Maine, Orono, ME 04469, USA
| |
Collapse
|
2
|
Shen L, Liu Y, Chen L, Lei T, Ren P, Ji M, Song W, Lin H, Su W, Wang S, Rooman M, Pucci F. Genomic basis of environmental adaptation in the widespread poly-extremophilic Exiguobacterium group. THE ISME JOURNAL 2024; 18:wrad020. [PMID: 38365240 PMCID: PMC10837837 DOI: 10.1093/ismejo/wrad020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 12/04/2023] [Accepted: 12/05/2023] [Indexed: 02/18/2024]
Abstract
Delineating cohesive ecological units and determining the genetic basis for their environmental adaptation are among the most important objectives in microbiology. In the last decade, many studies have been devoted to characterizing the genetic diversity in microbial populations to address these issues. However, the impact of extreme environmental conditions, such as temperature and salinity, on microbial ecology and evolution remains unclear so far. In order to better understand the mechanisms of adaptation, we studied the (pan)genome of Exiguobacterium, a poly-extremophile bacterium able to grow in a wide range of environments, from permafrost to hot springs. To have the genome for all known Exiguobacterium type strains, we first sequenced those that were not yet available. Using a reverse-ecology approach, we showed how the integration of phylogenomic information, genomic features, gene and pathway enrichment data, regulatory element analyses, protein amino acid composition, and protein structure analyses of the entire Exiguobacterium pangenome allows to sharply delineate ecological units consisting of mesophilic, psychrophilic, halophilic-mesophilic, and halophilic-thermophilic ecotypes. This in-depth study clarified the genetic basis of the defined ecotypes and identified some key mechanisms driving the environmental adaptation to extreme environments. Our study points the way to organizing the vast microbial diversity into meaningful ecologically units, which, in turn, provides insight into how microbial communities adapt and respond to different environmental conditions in a changing world.
Collapse
Affiliation(s)
- Liang Shen
- College of Life Sciences, Anhui Normal University, Wuhu 241000, China
- Anhui Provincial Key Laboratory of Molecular Enzymology and Mechanism of Major Diseases, and Anhui Provincial Engineering Research Centre for Molecular Detection and Diagnostics, Anhui Normal University, Wuhu 241000, China
| | - Yongqin Liu
- Center for the Pan-Third Pole Environment, Lanzhou University, Lanzhou 730000, China
| | - Liangzhong Chen
- College of Life Sciences, Anhui Normal University, Wuhu 241000, China
| | - Tingting Lei
- College of Life Sciences, Anhui Normal University, Wuhu 241000, China
| | - Ping Ren
- College of Life Sciences, Anhui Normal University, Wuhu 241000, China
| | - Mukan Ji
- Center for the Pan-Third Pole Environment, Lanzhou University, Lanzhou 730000, China
| | - Weizhi Song
- Centre for Marine Bio-Innovation, University of New South Wales, Sydney, NSW 2052, Australia
| | - Hao Lin
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Wei Su
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Sheng Wang
- Shanghai Zelixir Biotech Company Ltd., Shanghai 200030, China
| | - Marianne Rooman
- Computational Biology and Bioinformatics, Université Libre de Bruxelles, Brussels 1050, Belgium
- Interuniversity Institute of Bioinformatics in Brussels, Brussels 1050, Belgium
| | - Fabrizio Pucci
- Computational Biology and Bioinformatics, Université Libre de Bruxelles, Brussels 1050, Belgium
- Interuniversity Institute of Bioinformatics in Brussels, Brussels 1050, Belgium
| |
Collapse
|
3
|
Jiang ZM, Mou T, Sun Y, Su J, Yu LY, Zhang YQ. Environmental distribution and genomic characteristics of Solirubrobacter, with proposal of two novel species. Front Microbiol 2023; 14:1267771. [PMID: 38107860 PMCID: PMC10722151 DOI: 10.3389/fmicb.2023.1267771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 11/03/2023] [Indexed: 12/19/2023] Open
Abstract
Solirubrobacter spp. were abundant in soil samples collected from deserts and other areas with high UV radiation. In addition, a novel Solirubrobacter species, with strain CPCC 204708T as the type, was isolated and identified from sandy soil sample collected from the Badain Jaran Desert of the Inner Mongolia autonomous region. Strain CPCC 204708T was Gram-stain positive, rod-shaped, non-motile, non-spore-forming, and grew optimally at 28-30°C, pH 7.0-8.0, and in the absence of NaCl. Analysis of the 16S rRNA gene sequence of strain CPCC 204708T showed its identity within the genus Solirubrobacter, with highest nucleotide similarities (97.4-98.2%) to other named Solirubrobacter species. Phylogenetic and genomic analyses indicated that the strain was most closely related to Solirubrobacter phytolaccae KCTC 29190T, while represented a distinct species, as confirmed from physiological properties and comparison. The name Solirubrobacter deserti sp. nov. was consequently proposed, with CPCC 204708T (= DSM 105495T = NBRC 112942T) as the type strain. Genomic analyses of the Solirubrobacter spp. also suggested that Solirubrobacter sp. URHD0082 represents a novel species, for which the name Candidatus "Solirubrobacter pratensis" sp. nov. was proposed. Genomic analysis of CPCC 204708T revealed the presence of genes related to its adaptation to the harsh environments of deserts and may also harbor genes functional in plant-microbe interactions. Pan-genomic analysis of available Solirubrobacter spp. confirmed the presence of many of the above genes as core components of Solirubrobacter genomes and suggests they may possess beneficial potential for their associate plant and may be important resources for bioactive compounds.
Collapse
Affiliation(s)
- Zhu-Ming Jiang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- State Key Laboratory of Dao-di Herb, Beijing, China
| | - Tong Mou
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- State Key Laboratory of Dao-di Herb, Beijing, China
| | - Ye Sun
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jing Su
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Li-Yan Yu
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yu-Qin Zhang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- State Key Laboratory of Dao-di Herb, Beijing, China
| |
Collapse
|
4
|
Ferheen I, Ahmed Z, Alonazi WB, Pessina A, Ibrahim M, Pucciarelli S, Bokhari H. Diverse Repertoire and Relationship of Exopolysaccharide Genes in Cold-Adapted Acinetobacter sp. CUI-P1 Revealed by Comparative Genome Analysis. Microorganisms 2023; 11:microorganisms11040885. [PMID: 37110308 PMCID: PMC10143279 DOI: 10.3390/microorganisms11040885] [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: 02/21/2023] [Revised: 03/18/2023] [Accepted: 03/27/2023] [Indexed: 04/29/2023] Open
Abstract
This study focused on the exploration of microbial communities inhabiting extreme cold environments, such as the Passu and Pisan glaciers of Pakistan, and their potential utilization in industrial applications. Among the 25 initially screened strains, five were found to be suitable candidates for exopolysaccharide (EPS) production, with strain CUI-P1 displaying the highest yield of 7230.5 mg/L compared to the other four strains. The purified EPS from CUI-P1 was tested for its ability to protect probiotic bacteria and E. coli expressing green fluorescence protein (HriGFP) against extreme cold temperatures, and it exhibited excellent cryoprotectant and emulsification activity, highlighting its potential use in the biotechnological industry. Furthermore, the genome of Acinetobacter sp., CUI-P1 comprised 199 contigs, with a genome size of 10,493,143bp and a G + C content of 42%, and showed 98.197% nucleotide identity to the type genome of Acinetobacter baumannii ATCC 17978. These findings offer promising avenues for the application of EPS as a cryoprotectant, an essential tool in modern biotechnology.
Collapse
Affiliation(s)
- Ifra Ferheen
- Department of Biosciences, COMSATS University Islamabad, Islamabad 44000, Pakistan
| | - Zaheer Ahmed
- Department of Nutritional Sciences and Environmental Design, Allama Iqbal Open University, Islamabad 44000, Pakistan
| | - Wadi B Alonazi
- Health Administration Department, College of Business Administration, King Saud University, Riyadh 11587, Saudi Arabia
| | - Alex Pessina
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, 20126 Milan, Italy
| | - Muhammad Ibrahim
- Department of Biosciences, COMSATS University Islamabad, Sahiwal Campus, Sahiwal 55000, Pakistan
| | - Sandra Pucciarelli
- School of Biosciences and Veterinary Medicine, University of Camerino, 62032 Camerino, Italy
| | - Habib Bokhari
- Department of Microbiology, Kohsar University Murree, Murree 47150, Pakistan
| |
Collapse
|
5
|
Yu X, Jiang K, Zhang W, Dong S, Wu Y, Zhang G, Wu S, Chen T, Liu G. Purification, Identification, and Properties of a Novel Carotenoid Produced by Arthrobacter sp. QL17 Isolated from Mount Qomolangma. Antioxidants (Basel) 2022; 11:antiox11081493. [PMID: 36009212 PMCID: PMC9404904 DOI: 10.3390/antiox11081493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 07/26/2022] [Accepted: 07/27/2022] [Indexed: 02/04/2023] Open
Abstract
The genus Arthrobacter is a source of many natural products that are critical in the development of new medicines. Here, we isolated a novel carotenoid from Arthrobacter sp. QL17 and characterized its properties. The carotenoid was extracted with methanol, and purified by column chromatography and semi-preparative HPLC. Based on micrOTOF-Q and NMR analyses, the pigment was chemically characterized as 2,2′-((((1E,3E,5E,7E,9E,11E,13E,15E,17E,19E)-3,7,14,18-tetramethylicosa-1,3,5,7,9,11,13,15,17,19-decaene-1,20-diyl)bis(2,2,4-trimethylcyclohex-3-ene-3,1-diyl)) bis(ethan-2-yl-1-ylidene))bi(propane-1,3-diol), and named arthroxanthin. The biological activities of arthroxanthin were evaluated with DPPH, ABTS and MTT assays. Arthroxanthin exhibited excellent radical scavenging properties, as shown for 2, 20-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-n-(3, 2-ethyl-benzothiazole-6-sulfonic acid) ammonium salt (ABTS), respectively, with IC50s of 69.8 and 21.5 µg/mL. It also showed moderate anticancer activities against HepG2, Hela, MDAB-231, SW480, and MKN-45 with IC50 values of 107.6, 150.4, 143.4, 195.9, and 145.5 μg/mL, respectively. Therefore, arthroxanthin derived from Arthrobacter sp. QL17 may be a potent antioxidant and anticancer agent for food and pharmaceutical use.
Collapse
Affiliation(s)
- Xue Yu
- Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730030, China;
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Lanzhou 730030, China; (Y.W.); (G.Z.); (S.W.); (T.C.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kan Jiang
- Agronomy College, Gansu Agricultural University, Lanzhou 730070, China;
| | - Wei Zhang
- Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730030, China;
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Lanzhou 730030, China; (Y.W.); (G.Z.); (S.W.); (T.C.)
- Correspondence: (W.Z.); (G.L.)
| | - Shuqing Dong
- CAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730030, China;
| | - Yujie Wu
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Lanzhou 730030, China; (Y.W.); (G.Z.); (S.W.); (T.C.)
- University of Chinese Academy of Sciences, Beijing 100049, China
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730030, China
| | - Gaosen Zhang
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Lanzhou 730030, China; (Y.W.); (G.Z.); (S.W.); (T.C.)
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730030, China
| | - Shiyu Wu
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Lanzhou 730030, China; (Y.W.); (G.Z.); (S.W.); (T.C.)
| | - Tuo Chen
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Lanzhou 730030, China; (Y.W.); (G.Z.); (S.W.); (T.C.)
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730030, China
| | - Guangxiu Liu
- Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730030, China;
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Lanzhou 730030, China; (Y.W.); (G.Z.); (S.W.); (T.C.)
- Correspondence: (W.Z.); (G.L.)
| |
Collapse
|
6
|
Kumar V, Kashyap P, Kumar S, Thakur V, Kumar S, Singh D. Multiple Adaptive Strategies of Himalayan Iodobacter sp. PCH194 to High-Altitude Stresses. Front Microbiol 2022; 13:881873. [PMID: 35875582 PMCID: PMC9298515 DOI: 10.3389/fmicb.2022.881873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 06/01/2022] [Indexed: 11/24/2022] Open
Abstract
Bacterial adaption to the multiple stressed environments of high-altitude niches in the Himalayas is intriguing and is of considerable interest to biotechnologists. Previously, we studied the culturable and unculturable metagenome microbial diversity from glacial and kettle lakes in the Western Himalayas. In this study, we explored the adaptive strategies of a unique Himalayan eurypsychrophile Iodobacter sp. PCH194, which can synthesize polyhydroxybutyrate (PHB) and violacein pigment. Whole-genome sequencing and analysis of Iodobacter sp. PCH194 (4.58 Mb chromosome and three plasmids) revealed genetic traits associated with adaptive strategies for cold/freeze, nutritional fluctuation, defense against UV, acidic pH, and the kettle lake's competitive environment. Differential proteome analysis suggested the adaptive role of chaperones, ribonucleases, secretion systems, and antifreeze proteins under cold stress. Antifreeze activity inhibiting the ice recrystallization at −9°C demonstrated the bacterium's survival at subzero temperature. The bacterium stores carbon in the form of PHB under stress conditions responding to nutritional fluctuations. However, violacein pigment protects the cells from UV radiation. Concisely, genomic, proteomic, and physiological studies revealed the multiple adaptive strategies of Himalayan Iodobacter to survive the high-altitude stresses.
Collapse
Affiliation(s)
- Vijay Kumar
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, India
| | - Prakriti Kashyap
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, India
| | - Subhash Kumar
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, India.,Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre (CSIR-HRDC), Ghaziabad, India
| | - Vikas Thakur
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, India.,Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre (CSIR-HRDC), Ghaziabad, India
| | - Sanjay Kumar
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, India
| | - Dharam Singh
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, India.,Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre (CSIR-HRDC), Ghaziabad, India
| |
Collapse
|
7
|
Prokaryotic diversity and biogeochemical characteristics of benthic microbial ecosystems from James Ross Archipelago (West Antarctica). Polar Biol 2022. [DOI: 10.1007/s00300-021-02997-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
8
|
Cediel Becerra JDD, Suescún Sepúlveda JA, Fuentes JL. Prodigiosin Production and Photoprotective/Antigenotoxic Properties in Serratia marcescens Indigenous Strains from Eastern Cordillera of Colombia. Photochem Photobiol 2021; 98:254-261. [PMID: 34403528 DOI: 10.1111/php.13507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 08/12/2021] [Accepted: 08/16/2021] [Indexed: 11/29/2022]
Abstract
Serratia marcescens is a bacterial species that produces an antibacterial pigment (Prodigiosin) showing a wide adaptive response to environmental stresses. The study aimed to investigate Prodigiosin production in S. marcescens wild-type strains, as well as its relation to photoprotection and antigenotoxicity against UVB. Prodigiosin yield was spectrophotometrically assayed in extracts of bacterial strains grown in different culture media. In vitro photoprotection efficacy was evaluated using the in vitro indices sun protection factor (SPFin vitro ) and critical wavelength (λc). The percentage of UVB antigenotoxicity estimates (%GI) in the SOS Chromotest was also evaluated. Correlation analysis was used to examine the relationship between Prodigiosin yield, SPFin vitro , %GI estimates and environmental traits (altitude, temperature, rainfall and solar irradiance). Prodigiosin yield in S. marcescens strains varied depending on culture media used for its growth, and it was correlated with environmental variables such as temperature and solar irradiance. SPFin vitro estimates were well correlated with Prodigiosin concentration and %GI values in the bacterial strains being studied. UVB photoprotective efficacy of the extracts obtained from S. marcescens strains depends on the strain's Prodigiosin yield and its antigenotoxic potential. The extracts with Prodigiosin yield higher than ˜17 μg mL-1 could be used as sources of sunscreen ingredients.
Collapse
Affiliation(s)
- José D D Cediel Becerra
- Laboratorio de Microbiología y Mutagénesis Ambiental, Grupo de Investigación en Microbiología y Genética, Escuela de Biología, Universidad Industrial de Santander, Bucaramanga, Colombia
| | - Jhon Alexander Suescún Sepúlveda
- Laboratorio de Microbiología y Mutagénesis Ambiental, Grupo de Investigación en Microbiología y Genética, Escuela de Biología, Universidad Industrial de Santander, Bucaramanga, Colombia
| | - Jorge Luis Fuentes
- Laboratorio de Microbiología y Mutagénesis Ambiental, Grupo de Investigación en Microbiología y Genética, Escuela de Biología, Universidad Industrial de Santander, Bucaramanga, Colombia
| |
Collapse
|
9
|
Silva TRE, Silva LCF, de Queiroz AC, Alexandre Moreira MS, de Carvalho Fraga CA, de Menezes GCA, Rosa LH, Bicas J, de Oliveira VM, Duarte AWF. Pigments from Antarctic bacteria and their biotechnological applications. Crit Rev Biotechnol 2021; 41:809-826. [PMID: 33622142 DOI: 10.1080/07388551.2021.1888068] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Pigments from microorganisms have triggered great interest in the market, mostly by their "natural" appeal, their favorable production conditions, in addition to the potential new chemical structures or naturally overproducing strains. They have been used in: food, feed, dairy, textile, pharmaceutical, and cosmetic industries. The high rate of pigment production in microorganisms recovered from Antarctica in response to selective pressures such as: high UV radiation, low temperatures, and freezing and thawing cycles makes this a unique biome which means that much of its biological heritage cannot be found elsewhere on the planet. This vast arsenal of pigmented molecules has different functions in bacteria and may exhibit different biotechnological activities, such as: extracellular sunscreens, photoprotective function, antimicrobial activity, biodegradability, etc. However, many challenges for the commercial use of these compounds have yet to be overcome, such as: the low stability of natural pigments in cosmetic formulations, the change in color when subjected to pH variations, the low yield and the high costs in their production. This review surveys the different types of natural pigments found in Antarctic bacteria, classifying them according to their chemical structure. Finally, we give an overview of the main pigments that are used commercially today.
Collapse
Affiliation(s)
- Tiago Rodrigues E Silva
- Centro Pluridisciplinar de Pesquisas Químicas, Biológicas e Agrárias, Universidade Estadual de Campinas, UNICAMP, Campinas, Brazil
| | | | | | | | | | | | - Luiz Henrique Rosa
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Juliano Bicas
- Departamento de Ciência de Alimentos, Universidade Estadual de Campinas, UNICAMP, Campinas, Brazil
| | - Valéria Maia de Oliveira
- Centro Pluridisciplinar de Pesquisas Químicas, Biológicas e Agrárias, Universidade Estadual de Campinas, UNICAMP, Campinas, Brazil
| | | |
Collapse
|
10
|
Alem D, Marizcurrena JJ, Saravia V, Davyt D, Martinez-Lopez W, Castro-Sowinski S. Production and antiproliferative effect of violacein, a purple pigment produced by an Antarctic bacterial isolate. World J Microbiol Biotechnol 2020; 36:120. [DOI: 10.1007/s11274-020-02893-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 07/11/2020] [Indexed: 12/22/2022]
|
11
|
Sajjad W, Din G, Rafiq M, Iqbal A, Khan S, Zada S, Ali B, Kang S. Pigment production by cold-adapted bacteria and fungi: colorful tale of cryosphere with wide range applications. Extremophiles 2020; 24:447-473. [PMID: 32488508 PMCID: PMC7266124 DOI: 10.1007/s00792-020-01180-2] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 05/18/2020] [Indexed: 12/18/2022]
Abstract
Pigments are an essential part of everyday life on Earth with rapidly growing industrial and biomedical applications. Synthetic pigments account for a major portion of these pigments that in turn have deleterious effects on public health and environment. Such drawbacks of synthetic pigments have shifted the trend to use natural pigments that are considered as the best alternative to synthetic pigments due to their significant properties. Natural pigments from microorganisms are of great interest due to their broader applications in the pharmaceutical, food, and textile industry with increasing demand among the consumers opting for natural pigments. To fulfill the market demand of natural pigments new sources should be explored. Cold-adapted bacteria and fungi in the cryosphere produce a variety of pigments as a protective strategy against ecological stresses such as low temperature, oxidative stresses, and ultraviolet radiation making them a potential source for natural pigment production. This review highlights the protective strategies and pigment production by cold-adapted bacteria and fungi, their industrial and biomedical applications, condition optimization for maximum pigment extraction as well as the challenges facing in the exploitation of cryospheric microorganisms for pigment extraction that hopefully will provide valuable information, direction, and progress in forthcoming studies.
Collapse
Affiliation(s)
- Wasim Sajjad
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Ghufranud Din
- Department of Microbiology, Quaid-I-Azam University, Islamabad, 45320, Pakistan
| | - Muhammad Rafiq
- Department of Microbiology, Faculty of Life Sciences and Informatics, Balochistan University of IT, Engineering and Management Sciences, Quetta, Pakistan
| | - Awais Iqbal
- School of Life Sciences, State Key Laboratory of Grassland Agro-Ecosystems, Lanzhou University, Lanzhou, People's Republic of China
| | - Suliman Khan
- The Department of Cerebrovascular Diseases, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Sahib Zada
- Department of Biology, College of Science, Shantou University, Shantou, China
| | - Barkat Ali
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Shichang Kang
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.
- CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing, China.
| |
Collapse
|
12
|
Bajerski F, Bürger A, Glasmacher B, Keller ERJ, Müller K, Mühldorfer K, Nagel M, Rüdel H, Müller T, Schenkel J, Overmann J. Factors determining microbial colonization of liquid nitrogen storage tanks used for archiving biological samples. Appl Microbiol Biotechnol 2019; 104:131-144. [PMID: 31781817 PMCID: PMC6942587 DOI: 10.1007/s00253-019-10242-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 10/25/2019] [Accepted: 11/04/2019] [Indexed: 01/19/2023]
Abstract
The availability of bioresources is a precondition for life science research, medical applications, and diagnostics, but requires a dedicated quality management to guarantee reliable and safe storage. Anecdotal reports of bacterial isolates and sample contamination indicate that organisms may persist in liquid nitrogen (LN) storage tanks. To evaluate the safety status of cryocollections, we systematically screened organisms in the LN phase and in ice layers covering inner surfaces of storage tanks maintained in different biobanking facilities. We applied a culture-independent approach combining cell detection by epifluorescence microscopy with the amplification of group-specific marker genes and high-throughput sequencing of bacterial ribosomal genes. In the LN phase, neither cells nor bacterial 16S rRNA gene copy numbers were detectable (detection limit, 102 cells per ml, 103 gene copies per ml). In several cases, small numbers of bacteria of up to 104 cells per ml and up to 106 gene copies per ml, as well as Mycoplasma, or fungi were detected in the ice phase formed underneath the lids or accumulated at the bottom. The bacteria most likely originated from the stored materials themselves (Elizabethingia, Janthibacterium), the technical environment (Pseudomonas, Acinetobacter, Methylobacterium), or the human microbiome (Bacteroides, Streptococcus, Staphylococcus). In single cases, bacteria, Mycoplasma, fungi, and human cells were detected in the debris at the bottom of the storage tanks. In conclusion, the limited microbial load of the ice phase and in the debris of storage tanks can be effectively avoided by minimizing ice formation and by employing hermetically sealed sample containers.
Collapse
Affiliation(s)
- F Bajerski
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Inhoffenstraße 7B, Braunschweig, Germany.
| | - A Bürger
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Developmental Genetics, München, Germany
| | - B Glasmacher
- Institute for Multiphase Processes, Leibniz University Hannover, Hannover, Germany
| | - E R J Keller
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Seeland, OT Gatersleben, Germany
| | - K Müller
- Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW), Berlin, Germany
| | - K Mühldorfer
- Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW), Berlin, Germany
| | - M Nagel
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Seeland, OT Gatersleben, Germany
| | - H Rüdel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Schmallenberg, Germany
| | | | - J Schenkel
- German Cancer Research Centre, Heidelberg, Germany
- Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
| | - J Overmann
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Inhoffenstraße 7B, Braunschweig, Germany
- Microbiology, Braunschweig University of Technology, Braunschweig, Germany
| |
Collapse
|
13
|
Merino N, Aronson HS, Bojanova DP, Feyhl-Buska J, Wong ML, Zhang S, Giovannelli D. Living at the Extremes: Extremophiles and the Limits of Life in a Planetary Context. Front Microbiol 2019; 10:780. [PMID: 31037068 PMCID: PMC6476344 DOI: 10.3389/fmicb.2019.00780] [Citation(s) in RCA: 198] [Impact Index Per Article: 39.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 03/27/2019] [Indexed: 01/21/2023] Open
Abstract
Prokaryotic life has dominated most of the evolutionary history of our planet, evolving to occupy virtually all available environmental niches. Extremophiles, especially those thriving under multiple extremes, represent a key area of research for multiple disciplines, spanning from the study of adaptations to harsh conditions, to the biogeochemical cycling of elements. Extremophile research also has implications for origin of life studies and the search for life on other planetary and celestial bodies. In this article, we will review the current state of knowledge for the biospace in which life operates on Earth and will discuss it in a planetary context, highlighting knowledge gaps and areas of opportunity.
Collapse
Affiliation(s)
- Nancy Merino
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States.,Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan.,Biosciences and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Lab, Livermore, CA, United States
| | - Heidi S Aronson
- Department of Biology, University of Southern California, Los Angeles, CA, United States
| | - Diana P Bojanova
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Jayme Feyhl-Buska
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Michael L Wong
- Department of Astronomy - Astrobiology Program, University of Washington, Seattle, WA, United States.,NASA Astrobiology Institute's Virtual Planetary Laboratory, University of Washington, Seattle, WA, United States
| | - Shu Zhang
- Section of Infection and Immunity, Herman Ostrow School of Dentistry of USC, University of Southern California, Los Angeles, CA, United States
| | - Donato Giovannelli
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan.,Department of Biology, University of Naples "Federico II", Naples, Italy.,Department of Marine and Coastal Science, Rutgers, The State University of New Jersey, New Brunswick, NJ, United States.,Institute for Biological Resources and Marine Biotechnology, National Research Council of Italy, Ancona, Italy
| |
Collapse
|
14
|
Stress-Tolerance and Taxonomy of Culturable Bacterial Communities Isolated from a Central Mojave Desert Soil Sample. GEOSCIENCES 2019. [DOI: 10.3390/geosciences9040166] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The arid Mojave Desert is one of the most significant terrestrial analogue objects for astrobiological research due to its genesis, mineralogy, and climate. However, the knowledge of culturable bacterial communities found in this extreme ecotope’s soil is yet insufficient. Therefore, our research has been aimed to fulfil this lack of knowledge and improve the understanding of functioning of edaphic bacterial communities of the Central Mojave Desert soil. We characterized aerobic heterotrophic soil bacterial communities of the central region of the Mojave Desert. A high total number of prokaryotic cells and a high proportion of culturable forms in the soil studied were observed. Prevalence of Actinobacteria, Proteobacteria, and Firmicutes was discovered. The dominance of pigmented strains in culturable communities and high proportion of thermotolerant and pH-tolerant bacteria were detected. Resistance to a number of salts, including the ones found in Martian regolith, as well as antibiotic resistance, were also estimated.
Collapse
|
15
|
Amicucci A, Barbieri E, Sparvoli V, Gioacchini AM, Calcabrini C, Palma F, Stocchi V, Zambonelli A. Microbial and pigment profile of the reddish patch occurring within Tuber magnatum ascomata. Fungal Biol 2018; 122:1134-1141. [DOI: 10.1016/j.funbio.2018.07.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 07/19/2018] [Accepted: 07/23/2018] [Indexed: 01/17/2023]
|
16
|
Kumar A, Alam A, Tripathi D, Rani M, Khatoon H, Pandey S, Ehtesham NZ, Hasnain SE. Protein adaptations in extremophiles: An insight into extremophilic connection of mycobacterial proteome. Semin Cell Dev Biol 2018; 84:147-157. [PMID: 29331642 DOI: 10.1016/j.semcdb.2018.01.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 09/01/2017] [Accepted: 01/09/2018] [Indexed: 02/02/2023]
Abstract
The biological paradox about how extremophiles persist at extreme ecological conditions throws a fascinating picture of the enormous potential of a single cell to adapt to homeostatic conditions in order to propagate. Unicellular organisms face challenges from both environmental factors and the ecological niche provided by the host tissue. Although the existence of extremophiles and their physiological properties were known for a long time, availability of whole genome sequence has catapulted the study on mechanisms of adaptation and the underlying principles that have enabled these unique organisms to withstand evolutionary and environmental pressures. Comparative genomics has shown that extremophiles possess the unique set of genes and proteins that empower them with biochemical machinery necessary to thrive in extreme environments. The presence of these proteins safeguards the cell against a wide array of extreme conditions such as temperature, pressure, radiations, chemicals, drugs etc. An insight into these adaptive mechanisms in extremophiles may help us to devise strategies to alter the genes and proteins that may have therapeutic potential and commercial value. Here we present an overview of the various adaptations in extremophiles. We also try to explain how mycobacterium channelizes its proteome to survive in stress conditions posed by host immune system.
Collapse
Affiliation(s)
- Ashutosh Kumar
- Molecular Infection and Functional Biology Lab, Kusuma School of Biological Sciences, Indian Institute of Technology-Delhi, New Delhi, India
| | - Anwar Alam
- Molecular Infection and Functional Biology Lab, Kusuma School of Biological Sciences, Indian Institute of Technology-Delhi, New Delhi, India
| | - Deeksha Tripathi
- Department of Microbiology, Central University of Rajasthan, Bandar Sindri, Ajmer, Rajasthan, India
| | - Mamta Rani
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology-Delhi, New Delhi, India
| | - Hafeeza Khatoon
- Molecular Infection and Functional Biology Lab, Kusuma School of Biological Sciences, Indian Institute of Technology-Delhi, New Delhi, India
| | - Saurabh Pandey
- National Institute of Pathology, Safdarjang Hospital Campus, New Delhi, India
| | - Nasreen Z Ehtesham
- National Institute of Pathology, Safdarjang Hospital Campus, New Delhi, India
| | - Seyed E Hasnain
- Molecular Infection and Functional Biology Lab, Kusuma School of Biological Sciences, Indian Institute of Technology-Delhi, New Delhi, India; JH-Institute of Molecular Medicine, Hamdard Nagar, New Delhi, India; Dr Reddy's Institute of Life Sciences, University of Hyderabad Campus, Hyderabad, India.
| |
Collapse
|
17
|
Beckstead AA, Zhang Y, Hilmer JK, Smith HJ, Bermel E, Foreman CM, Kohler B. Ultrafast Excited-State Deactivation of the Bacterial Pigment Violacein. J Phys Chem B 2017; 121:7855-7861. [PMID: 28792753 DOI: 10.1021/acs.jpcb.7b05769] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The photophysical properties of the natural pigment violacein extracted from an Antarctic organism adapted to high exposure levels of UV radiation were measured in a combined steady-state and time-resolved spectroscopic study for the first time. In the low-viscosity solvents methanol and acetone, violacein exhibits low fluorescence quantum yields on the order of 1 × 10-4, and femtosecond transient absorption measurements reveal excited-state lifetimes of 3.2 ± 0.2 and 4.5 ± 0.2 ps in methanol and acetone, respectively. As solvent viscosity is increased, both the fluorescence quantum yield and excited-state lifetime of this intensely colored pigment increase dramatically, and stimulated emission decays 30-fold more slowly in glycerol than in methanol at room temperature. Excited-state deactivation is suggested to occur via a molecular-rotor mechanism in which torsion about an interring bond leads to a conical intersection with the ground state.
Collapse
Affiliation(s)
| | - Yuyuan Zhang
- Department of Chemistry and Biochemistry, The Ohio State University , 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | | | | | | | | | - Bern Kohler
- Department of Chemistry and Biochemistry, The Ohio State University , 100 West 18th Avenue, Columbus, Ohio 43210, United States
| |
Collapse
|
18
|
Beckstead AA, Zhang Y, Hilmer JK, Smith HJ, Bermel E, Foreman CM, Kohler B. Ultrafast Excited-State Deactivation of the Bacterial Pigment Violacein. J Phys Chem A 2017:acs.jpca.7b05769. [PMID: 28753006 DOI: 10.1021/acs.jpca.7b05769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The photophysical properties of the natural pigment violacein extracted from an Antarctic organism adapted to high exposure levels of UV radiation were measured in a combined steady-state and time-resolved spectroscopic study for the first time. In the low-viscosity solvents methanol and acetone, violacein exhibits low fluorescence quantum yields on the order of 10-4, and femtosecond transient absorption measurements reveal excited-state lifetimes of 3.2 ± 0.2 and 4.5 ± 0.2 picoseconds in methanol and acetone, respectively. As solvent viscosity is increased, both the fluorescence quantum yield and excited-state lifetime of this intensely colored pigment increase dramatically and stimulated emission decays 30-fold more slowly in glycerol than in methanol at room temperature. Excited-state deactivation is suggested to occur via a molecular-rotor mechanism in which torsion about an interring bond leads to a conical intersection with the ground state.
Collapse
|
19
|
Smith HJ, Foreman CM, Akiyama T, Franklin MJ, Devitt NP, Ramaraj T. Genome Sequence of Janthinobacterium sp. CG23_2, a Violacein-Producing Isolate from an Antarctic Supraglacial Stream. GENOME ANNOUNCEMENTS 2016; 4:e01468-15. [PMID: 26823573 PMCID: PMC4732326 DOI: 10.1128/genomea.01468-15] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 12/07/2015] [Indexed: 11/29/2022]
Abstract
Here, we present the draft genome sequence for the violacein-producing Janthinobacterium sp. CG23_2 isolated from an Antarctic supraglacial stream. The genome is ~7.85 Mb, with a G+C content of 63.5%. The genome includes 7,247 candidate protein coding genes, which may provide insight into UV tolerance mechanisms.
Collapse
Affiliation(s)
- Heidi J Smith
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana, USA
| | - Christine M Foreman
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana, USA
| | - Tatsuya Akiyama
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana, USA
| | - Michael J Franklin
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana, USA
| | - Nicolas P Devitt
- National Center for Genome Resources (NCGR), Santa Fe, New Mexico, USA
| | | |
Collapse
|
20
|
Draft Genome Sequence of Janthinobacterium sp. Ant5-2-1, Isolated from Proglacial Lake Podprudnoye in the Schirmacher Oasis of East Antarctica. GENOME ANNOUNCEMENTS 2016; 4:4/1/e01600-15. [PMID: 26798103 PMCID: PMC4722270 DOI: 10.1128/genomea.01600-15] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Janthinobacterium sp. Ant5-2-1, isolated from the Schirmacher Oasis of East Antarctica, produces a purple-violet pigment, manifests diverse energy metabolism abilities, and tolerates cold, ultraviolet radiation, and other environmental stressors. We report here the 6.19-Mb draft genome of strain Ant5-2-1, which will help understand its survival mechanisms in extreme Antarctic ecosystems.
Collapse
|
21
|
Distribution of cold adaptation proteins in microbial mats in Lake Joyce, Antarctica: Analysis of metagenomic data by using two bioinformatics tools. J Microbiol Methods 2016; 120:23-8. [DOI: 10.1016/j.mimet.2015.11.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 11/09/2015] [Accepted: 11/09/2015] [Indexed: 11/18/2022]
|
22
|
Puja G, Jyoti V. Culturable bacterial diversity and hydrolytic enzymes from drass, a cold desert in India. ACTA ACUST UNITED AC 2015. [DOI: 10.5897/ajmr2015.7424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
|
23
|
Bacterial composition of soils of the Lake Wellman area, Darwin Mountains, Antarctica. Extremophiles 2013; 17:775-86. [PMID: 23820800 DOI: 10.1007/s00792-013-0560-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 06/18/2013] [Indexed: 10/26/2022]
Abstract
The aim of this study was to examine the bacterial composition of high latitude soils from the Darwin-Hatherton glacier region of Antarctica. Four soil pits on each of four glacial drift sheets were sampled for chemical and microbial analyses. The four drifts-Hatherton, Britannia, Danum, and Isca-ranged, respectively, from early Holocene (10 ky) to mid-Quaternary (ca 900 ky). Numbers of culturable bacteria were low, with highest levels detected in soils from the younger Hatherton drift. DNA was extracted and 16S rRNA gene clone libraries prepared from samples below the desert pavement for each of the four drift sheets. Between 31 and 262 clones were analysed from each of the Hatherton, Britannia, and Danum drifts. Bacterial sequences were dominated by members of the phyla Deinococcus-Thermus, Actinobacteria, and Bacteroidetes. Culturable bacteria, including some that clustered with soil clones (e.g., members of the genera Arthrobacter, Adhaeribacter, and Pontibacter), belonged to Actinobacteria and Bacteroidetes. The isolated bacteria are ideal model organisms for genomic and phenotypic investigations of those attributes that allow bacteria to survive and/or grow in Antarctic soils because they have close relatives that are not tolerant of these conditions.
Collapse
|