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Shyaula M, Regmi S, Khadka D, Poudel RC, Dhakal A, Koirala D, Sijapati J, Singh A, Maharjan J. Characterization of Thermostable Cellulase from Bacillus licheniformis PANG L Isolated from the Himalayan Soil. Int J Microbiol 2023; 2023:3615757. [PMID: 37692921 PMCID: PMC10484656 DOI: 10.1155/2023/3615757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 07/13/2023] [Accepted: 08/12/2023] [Indexed: 09/12/2023] Open
Abstract
This study aimed to isolate, purify, and characterize a potential thermophilic cellulase-producing bacterium from the Himalayan soil. Eleven thermophilic bacteria were isolated, and the strain PANG L was found to be the most potent cellulolytic producer. Morphological, physiological, biochemical, and molecular characterization identified PANG L as Bacillus licheniformis. This is the first study on the isolation of thermostable cellulase-producing Bacillus licheniformis from the Himalayan soil. This bacterium was processed for the production of cellulase enzyme. The optimum conditions for cellulase production were achieved at 45°C after 48 h of incubation at pH 6.5 in media-containing carboxymethyl cellulose (CMC) and yeast extract as carbon and nitrogen sources, respectively, in a thermo-shaker at 100 rpm. The enzyme was partially purified by 80% ammonium sulphate precipitation followed by dialysis, resulting in a 1.52-fold purification. The optimal activity of partially purified cellulase was observed at a temperature of 60°C and pH 5. The cellulase enzyme was stable within the pH ranges of 3-5 and retained 67% of activity even at 55°C. Cellulase activity was found to be enhanced in the presence of metal ions such as Cd2+, Pb2+, and Ba2+. The enzyme showed the highest activity when CMC was used as a substrate, followed by cellobiose. The Km and Vmax values of the enzyme were 1.8 mg/ml and 10.92 μg/ml/min, respectively. The cellulase enzyme obtained from Bacillus licheniformis PANG L had suitable catalytic properties for use in industrial applications.
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Affiliation(s)
- Manita Shyaula
- Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu, Nepal
- Nepal Academy of Science and Technology, Khumaltar, Lalitpur, Nepal
| | - Sunil Regmi
- Nepal Academy of Science and Technology, Khumaltar, Lalitpur, Nepal
| | - Deegendra Khadka
- Nepal Academy of Science and Technology, Khumaltar, Lalitpur, Nepal
| | | | - Agni Dhakal
- Nepal Academy of Science and Technology, Khumaltar, Lalitpur, Nepal
| | - Devesh Koirala
- Nepal Academy of Science and Technology, Khumaltar, Lalitpur, Nepal
| | | | - Anjana Singh
- Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu, Nepal
| | - Jyoti Maharjan
- Nepal Academy of Science and Technology, Khumaltar, Lalitpur, Nepal
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2
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Gonzalez JM, Santana MM, Gomez EJ, Delgado JA. Soil Thermophiles and Their Extracellular Enzymes: A Set of Capabilities Able to Provide Significant Services and Risks. Microorganisms 2023; 11:1650. [PMID: 37512823 PMCID: PMC10386326 DOI: 10.3390/microorganisms11071650] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 06/20/2023] [Accepted: 06/21/2023] [Indexed: 07/30/2023] Open
Abstract
During this century, a number of reports have described the potential roles of thermophiles in the upper soil layers during high-temperature periods. This study evaluates the capabilities of these microorganisms and proposes some potential consequences and risks associated with the activity of soil thermophiles. They are active in organic matter mineralization, releasing inorganic nutrients (C, S, N, P) that otherwise remain trapped in the organic complexity of soil. To process complex organic compounds in soils, these thermophiles require extracellular enzymes to break down large polymers into simple compounds, which can be incorporated into the cells and processed. Soil thermophiles are able to adapt their extracellular enzyme activities to environmental conditions. These enzymes can present optimum activity under high temperatures and reduced water content. Consequently, these microorganisms have been shown to actively process and decompose substances (including pollutants) under extreme conditions (i.e., desiccation and heat) in soils. While nutrient cycling is a highly beneficial process to maintain soil service quality, progressive warming can lead to excessive activity of soil thermophiles and their extracellular enzymes. If this activity is too high, it may lead to reduction in soil organic matter, nutrient impoverishment and to an increased risk of aridity. This is a clear example of a potential effect of future predicted climate warming directly caused by soil microorganisms with major consequences for our understanding of ecosystem functioning, soil health and the risk of soil aridity.
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Affiliation(s)
- Juan M Gonzalez
- Institute of Natural Resources and Agrobiology, IRNAS-CSIC, Avda. Reina Mercedes 10, E-41012 Sevilla, Spain
| | - Margarida M Santana
- Centre for Ecology, Evolution and Environmental Changes (cE3c) & Global Change and Sustainability Institute (CHANGE), Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Enrique J Gomez
- Institute of Natural Resources and Agrobiology, IRNAS-CSIC, Avda. Reina Mercedes 10, E-41012 Sevilla, Spain
| | - José A Delgado
- Department of Engineering, University of Loyola, Avda. de las Universidades, E-41704 Dos Hermanas, Spain
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3
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DePoy AN, King GM. Distribution and diversity of anaerobic thermophiles and putative anaerobic nickel-dependent carbon monoxide-oxidizing thermophiles in mesothermal soils and sediments. Front Microbiol 2023; 13:1096186. [PMID: 36699584 PMCID: PMC9868602 DOI: 10.3389/fmicb.2022.1096186] [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: 11/11/2022] [Accepted: 12/15/2022] [Indexed: 01/11/2023] Open
Abstract
Even though thermophiles are best known from geothermal and other heated systems, numerous studies have demonstrated that they occur ubiquitously in mesothermal and permanently cold soils and sediments. Cultivation based studies of the latter have revealed that the thermophiles within them are mostly spore-forming members of the Firmicutes. Since the geographic distribution of spores is presumably unconstrained by transport through the atmosphere, similar communities (composition and diversity) of thermophiles might be expected to emerge in mesothermal habitats after they are heated. Alternatively, thermophiles might experience environmental selection before or after heating leading to divergent communities. After demonstrating the ubiquity of anaerobic thermophiles and CO uptake in a variety of mesothermal habitats and two hot springs, we used high throughput sequencing of 16S rRNA genes to assess the composition and diversity of populations that emerged after incubation at 60°C with or without headspace CO concentrations of 25%. Anaerobic Firmicutes dominated relative abundances at most sites but anaerobic thermophilic members of the Acidobacteria and Proteobacteria were also common. Nonetheless, compositions at the amplicon sequence variant (ASV) level varied among the sites with no convergence resulting from heating or CO addition as indicated by beta diversity analyses. The distinctions among thermophilic communities paralleled patterns observed for unheated "time zero" mesothermal soils and sediments. Occupancy analyses showed that the number of ASVs occupying each of n sites decreased unimodally with increasing n; no ASV occupied all 14 sites and only one each occupied 11 and 12 sites, while 69.3% of 1873 ASVs occupied just one site. Nonetheless, considerations of distances among the sites occupied by individual ASVs along with details of their distributions indicated that taxa were not dispersal limited but rather were constrained by environmental selection. This conclusion was supported by βMNTD and βNTI analyses, which showed dispersal limitation was only a minor contributor to taxon distributions.
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4
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Milojevic T, Cramm MA, Hubert CRJ, Westall F. "Freezing" Thermophiles: From One Temperature Extreme to Another. Microorganisms 2022; 10:microorganisms10122417. [PMID: 36557670 PMCID: PMC9782878 DOI: 10.3390/microorganisms10122417] [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: 09/30/2022] [Revised: 11/23/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022] Open
Abstract
New detections of thermophiles in psychrobiotic (i.e., bearing cold-tolerant life forms) marine and terrestrial habitats including Arctic marine sediments, Antarctic accretion ice, permafrost, and elsewhere are continually being reported. These microorganisms present great opportunities for microbial ecologists to examine biogeographical processes for spore-formers and non-spore-formers alike, including dispersal histories connecting warm and cold biospheres. In this review, we examine different examples of thermophiles in cryobiotic locations, and highlight exploration of thermophiles at cold temperatures under laboratory conditions. The survival of thermophiles in psychrobiotic environments provokes novel considerations of physiological and molecular mechanisms underlying natural cryopreservation of microorganisms. Cultures of thermophiles maintained at low temperature may serve as a non-sporulating laboratory model for further exploration of metabolic potential of thermophiles at psychrobiotic temperatures, as well as for elucidating molecular mechanisms behind natural preservation and adaptation to psychrobiotic environments. These investigations are highly relevant for the search for life on other cold and icy planets in the Solar System, such as Mars, Europa and Enceladus.
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Affiliation(s)
- Tetyana Milojevic
- Exobiology Group, CNRS-Centre de Biophysique Moléculaire, University of Orléans, Rue Charles Sadron, CEDEX 2, 45071 Orléans, France
- Correspondence: ; Tel.: +33-2-3825-5548
| | - Margaret Anne Cramm
- Geomicrobiology Group, Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada
| | - Casey R. J. Hubert
- Geomicrobiology Group, Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada
| | - Frances Westall
- Exobiology Group, CNRS-Centre de Biophysique Moléculaire, Rue Charles Sadron, CEDEX 2, 45071 Orléans, France
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5
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Weingarten EA, Zee PC, Jackson CR. Microbial Communities in Saltpan Sediments Show Tolerance to Mars Analog Conditions, but Susceptibility to Chloride and Perchlorate Toxicity. ASTROBIOLOGY 2022; 22:838-850. [PMID: 35731161 PMCID: PMC9464085 DOI: 10.1089/ast.2021.0132] [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: 08/12/2021] [Accepted: 02/28/2022] [Indexed: 06/15/2023]
Abstract
Brines at or near the surface of present-day Mars are a potential explanation for seasonally recurring dark streaks on the walls of craters, termed recurring slope lineae (RSL). Deliquescence and freezing point depression are possible drivers of brine stability, attributable to the high salinity observed in martian regolith including chlorides and perchlorates. Investigation of life, which may inhabit RSL, and the cellular mechanisms necessary for survival, must consider the tolerance of highly variable hydration, freeze-thaw cycles, and high osmolarity in addition to the anaerobic, oligotrophic, and irradiated environment. We propose the saltpan, an ephemeral, hypersaline wetland as an analogue for putative RSL hydrology. Saltpan sediment archaeal and bacterial communities showed tolerance of the Mars-analogous atmosphere, hydration, minerology, salinity, and temperature. Although active growth and a shift to well-adapted taxa were observed, susceptibility to low-concentration chloride and perchlorate addition suggested that such a composition was insufficient for beneficial water retention relative to added salt stress.
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Affiliation(s)
- Eric A. Weingarten
- Department of Biology, University of Mississippi, University, Mississippi, USA
- U.S. Army Engineer Research and Development Center, Vicksburg, Mississippi, USA
| | - Peter C. Zee
- Department of Biology, University of Mississippi, University, Mississippi, USA
| | - Colin R. Jackson
- Department of Biology, University of Mississippi, University, Mississippi, USA
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6
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Wilson CK, King GM. Short-Term Exposure to Thermophilic Temperatures Facilitates CO Uptake by Thermophiles Maintained under Predominantly Mesophilic Conditions. Microorganisms 2022; 10:microorganisms10030656. [PMID: 35336231 PMCID: PMC8953250 DOI: 10.3390/microorganisms10030656] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/02/2022] [Accepted: 03/10/2022] [Indexed: 01/27/2023] Open
Abstract
Three phylogenetically and phenotypically distinct CO-oxidizing thermophiles (Alicyclobacillus macrosporangiidus CPP55 (Firmicutes), Meiothermus ruber PS4 (Deinococcus-Thermus) and Thermogemmatispora carboxidovorans PM5T (Chloroflexi)) and one CO-oxidizing mesophile (Paraburkholderia paradisi WAT (Betaproteobacteria)) isolated from volcanic soils were used to assess growth responses and CO uptake rates during incubations with constant temperatures (25 °C and 55 °C) and during multi-day incubations with a temperature regime that cycled between 20 °C and 55 °C on a diurnal basis (alternating mesophilic and thermophilic temperatures, AMTT). The results were used to test a conjecture that some thermophiles can survive in mesothermal habitats that experience occasional thermophilic temperatures. Meiothermus ruber PS4, which does not form spores, was able to grow and oxidize CO under all conditions, while the spore-forming Alicyclobacillus macrosporangiidus CPP55 grew and oxidized CO during the AMTT regime and at 55 °C, but was not active at 25 °C. Thermogemmatispora carboxidovorans PM5T, also a spore former, only grew at 55 °C but oxidized CO during AMTT and 55 °C incubations. In contrast, the non-sporing mesophile, Paraburkholderia paradisi WAT, was only able to grow and oxidize CO at 25 °C; growth and CO uptake ceased during the AMTT incubations after exposure to the initial round of thermophilic temperatures. Collectively, these results suggest that temporary, periodic exposure to permissive growth temperatures could help maintain populations of thermophiles in mesothermal habitats after deposition from the atmosphere or other sources.
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7
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Gomez EJ, Delgado JA, Gonzalez JM. Influence of water availability and temperature on estimates of microbial extracellular enzyme activity. PeerJ 2021; 9:e10994. [PMID: 33717705 PMCID: PMC7936561 DOI: 10.7717/peerj.10994] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 02/01/2021] [Indexed: 12/28/2022] Open
Abstract
Soils are highly heterogeneous and support highly diverse microbial communities. Microbial extracellular enzymes breakdown complex polymers into small assimilable molecules representing the limiting step of soil organic matter mineralization. This process occurs on to soil particles although currently it is typically estimated in laboratory aqueous solutions. Herein, estimates of microbial extracellular enzyme activity were obtained over a broad range of temperatures and water availabilities frequently observed at soil upper layers. A Pseudomonas strain presented optimum extracellular enzyme activities at high water activity whereas a desiccation resistant bacterium (Deinococcus) and a soil thermophilic isolate (Parageobacillus) showed optimum extracellular enzyme activity under dried (i.e., water activities ranging 0.5–0.8) rather that wet conditions. Different unamended soils presented a distinctive response of extracellular enzyme activity as a function of temperature and water availability. This study presents a procedure to obtain realistic estimates of microbial extracellular enzyme activity under natural soil conditions of extreme water availability and temperature. Improving estimates of microbial extracellular enzyme activity contribute to better understand the role of microorganisms in soils.
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Affiliation(s)
- Enrique J Gomez
- Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, IRNAS-CSIC, Sevilla, Spain
| | - Jose A Delgado
- Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, IRNAS-CSIC, Sevilla, Spain
| | - Juan M Gonzalez
- Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, IRNAS-CSIC, Sevilla, Spain
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8
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Gonçalves E Silva F, Dos Santos HF, de Assis Leite DC, Lutfi DS, Vianna M, Rosado AS. Skin and stinger bacterial communities in two critically endangered rays from the South Atlantic in natural and aquarium settings. Microbiologyopen 2020; 9:e1141. [PMID: 33226191 PMCID: PMC7755814 DOI: 10.1002/mbo3.1141] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/05/2020] [Accepted: 11/07/2020] [Indexed: 01/04/2023] Open
Abstract
Bacterial communities of two critically endangered rays from the South Atlantic, the butterfly ray (Gymnura altavela) and the groovebelly ray (Dasyatis hypostigma), were described using 16S rRNA gene metabarcoding. The study characterized the bacterial communities associated with (i) G. altavela in natural (in situ) and aquarium (ex situ) settings, (ii) skin and stinger of G. altavela, and D. hypostigma in aquaria, and (iii) newborns and adults of D. hypostigma. The results revealed potentially antibiotic‐producing bacterial groups on the skin of rays from the natural environment, and some taxa with the potential to benefit ray health, mainly in rays from the natural environment, as well as possible pathogens to other animals, including fish and humans. Differences were observed between the G. altavela and D. hypostigma bacteria composition, as well as between the skin and stinger bacterial composition. The bacterial community associated with D. hypostigma changed with the age of the ray. The aquarium environment severely impacted the G. altavela bacteria composition, which changed from a complex bacterial community to one dominated almost exclusively by two taxa, Oceanimonas sp. and Sediminibacterium sp. on the skin and stinger, respectively.
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Affiliation(s)
- Fernanda Gonçalves E Silva
- BioTecPesca-Laboratory of Biology and Fisheries Technology-Institute of Biology, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil.,LEMM, Laboratory of Molecular Microbial Ecology, Institute of Microbiology Paulo de Góes, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil.,The Oceanography Graduate Program of University of Rio de Janeiro State (PPG-OCN/UERJ), Rio de Janeiro, Brazil
| | | | | | | | - Marcelo Vianna
- BioTecPesca-Laboratory of Biology and Fisheries Technology-Institute of Biology, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil.,The Oceanography Graduate Program of University of Rio de Janeiro State (PPG-OCN/UERJ), Rio de Janeiro, Brazil.,IMAM-AquaRio-Rio de Janeiro Aquarium Research Center, Rio de Janeiro, Brazil
| | - Alexandre Soares Rosado
- LEMM, Laboratory of Molecular Microbial Ecology, Institute of Microbiology Paulo de Góes, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil.,IMAM-AquaRio-Rio de Janeiro Aquarium Research Center, Rio de Janeiro, Brazil
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9
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Adlan NA, Sabri S, Masomian M, Ali MSM, Rahman RNZRA. Microbial Biodegradation of Paraffin Wax in Malaysian Crude Oil Mediated by Degradative Enzymes. Front Microbiol 2020; 11:565608. [PMID: 33013795 PMCID: PMC7506063 DOI: 10.3389/fmicb.2020.565608] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 08/13/2020] [Indexed: 11/26/2022] Open
Abstract
The deposition of paraffin wax in crude oil is a problem faced by the oil and gas industry during extraction, transportation, and refining of crude oil. Most of the commercialized chemical additives to prevent wax are expensive and toxic. As an environmentally friendly alternative, this study aims to find a novel thermophilic bacterial strain capable of degrading paraffin wax in crude oil to control wax deposition. To achieve this, the biodegradation of crude oil paraffin wax by 11 bacteria isolated from seawater and oil-contaminated soil samples was investigated at 70°C. The bacteria were identified as Geobacillus kaustophilus N3A7, NFA23, DFY1, Geobacillus jurassicus MK7, Geobacillus thermocatenulatus T7, Parageobacillus caldoxylosilyticus DFY3 and AZ72, Anoxybacillus geothermalis D9, Geobacillus stearothermophilus SA36, AD11, and AD24. The GCMS analysis showed that strains N3A7, MK7, DFY1, AD11, and AD24 achieved more than 70% biodegradation efficiency of crude oil in a short period (3 days). Notably, most of the strains could completely degrade C37–C40 and increase the ratio of C14–C18, especially during the initial 2 days incubation. In addition, the degradation of crude oil also resulted in changes in the pH of the medium. The degradation of crude oil is associated with the production of degradative enzymes such as alkane monooxygenase, alcohol dehydrogenase, lipase, and esterase. Among the 11 strains, the highest activities of alkane monooxygenase were recorded in strain AD24. A comparatively higher overall alcohol dehydrogenase, lipase, and esterase activities were observed in strains N3A7, MK7, DFY1, AD11, and AD24. Thus, there is a potential to use these strains in oil reservoirs, crude oil processing, and recovery to control wax deposition. Their ability to withstand high temperature and produce degradative enzymes for long-chain hydrocarbon degradation led to an increase in the short-chain hydrocarbon ratio, and subsequently, improving the quality of the oil.
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Affiliation(s)
- Nur Aina Adlan
- Enzyme and Microbial Technology Research Centre, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Malaysia.,Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Malaysia
| | - Suriana Sabri
- Enzyme and Microbial Technology Research Centre, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Malaysia.,Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Malaysia
| | - Malihe Masomian
- Enzyme and Microbial Technology Research Centre, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Malaysia.,Centre for Virus and Vaccine Research, School of Science and Technology, Sunway University, Bandar Sunway, Malaysia
| | - Mohd Shukuri Mohamad Ali
- Enzyme and Microbial Technology Research Centre, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Malaysia.,Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Malaysia
| | - Raja Noor Zaliha Raja Abd Rahman
- Enzyme and Microbial Technology Research Centre, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Malaysia.,Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Malaysia
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10
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Gomez EJ, Delgado JA, Gonzalez JM. Environmental factors affect the response of microbial extracellular enzyme activity in soils when determined as a function of water availability and temperature. Ecol Evol 2020; 10:10105-10115. [PMID: 33005367 PMCID: PMC7520203 DOI: 10.1002/ece3.6672] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 01/16/2020] [Accepted: 02/07/2020] [Indexed: 11/21/2022] Open
Abstract
Microorganisms govern soil carbon cycling with critical effects at local and global scales. The activity of microbial extracellular enzymes is generally the limiting step for soil organic matter mineralization. Nevertheless, the influence of soil characteristics and climate parameters on microbial extracellular enzyme activity (EEA) performance at different water availabilities and temperatures remains to be detailed. Different soils from the Iberian Peninsula presenting distinctive climatic scenarios were sampled for these analyses. Results showed that microbial EEA in the mesophilic temperature range presents optimal rates under wet conditions (high water availability) while activity at the thermophilic temperature range (60°C) could present maximum EEA rates under dry conditions if the soil is frequently exposed to high temperatures. Optimum water availability conditions for maximum soil microbial EEA were influenced mainly by soil texture. Soil properties and climatic parameters are major environmental components ruling soil water availability and temperature which were decisive factors regulating soil microbial EEA. This study contributes decisively to the understanding of environmental factors on the microbial EEA in soils, specifically on the decisive influence of water availability and temperature on EEA. Unlike previous belief, optimum EEA in high temperature exposed soil upper layers can occur at low water availability (i.e., dryness) and high temperatures. This study shows the potential for a significant response by soil microbial EEA under conditions of high temperature and dryness due to a progressive environmental warming which will influence organic carbon decomposition at local and global scenarios.
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Affiliation(s)
- Enrique J. Gomez
- Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones CientíficasIRNAS‐CSICSevillaSpain
| | - José A. Delgado
- Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones CientíficasIRNAS‐CSICSevillaSpain
| | - Juan M. Gonzalez
- Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones CientíficasIRNAS‐CSICSevillaSpain
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11
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Gómez EJ, Delgado JA, González JM. Persistence of microbial extracellular enzymes in soils under different temperatures and water availabilities. Ecol Evol 2020; 10:10167-10176. [PMID: 33005372 PMCID: PMC7520220 DOI: 10.1002/ece3.6677] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 03/16/2020] [Accepted: 04/07/2020] [Indexed: 11/24/2022] Open
Abstract
Microbial extracellular enzyme activity (EEA) is critical for the decomposition of organic matter in soils. Generally, EEA represents the limiting step governing soil organic matter mineralization. The high complexity of soil microbial communities and the heterogeneity of soils suggest potentially complex interactions between microorganisms (and their extracellular enzymes), organic matter, and physicochemical factors. Previous studies have reported the existence of maximum soil EEA at high temperatures although microorganisms thriving at high temperature represent a minority of soil microbial communities. To solve this paradox, we attempt to evaluate if soil extracellular enzymes from thermophiles could accumulate in soils. Methodology at this respect is scarce and an adapted protocol is proposed. Herein, the approach is to analyze the persistence of soil microbial extracellular enzymes at different temperatures and under a broad range of water availability. Results suggest that soil high-temperature EEA presented longer persistence than enzymes with optimum activity at moderate temperature. Water availability influenced enzyme persistence, generally preserving for longer time the extracellular enzymes. These results suggest that high-temperature extracellular enzymes could be naturally accumulated in soils. Thus, soils could contain a reservoir of enzymes allowing a quick response by soil microorganisms to changing conditions. This study suggests the existence of novel mechanisms of interaction among microorganisms, their enzymes and the soil environment with relevance at local and global levels.
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Affiliation(s)
- Enrique J. Gómez
- Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS)Consejo Superior de Investigaciones Científicas (CSIC)SevillaSpain
| | - Jose A. Delgado
- Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS)Consejo Superior de Investigaciones Científicas (CSIC)SevillaSpain
| | - Juan M. González
- Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS)Consejo Superior de Investigaciones Científicas (CSIC)SevillaSpain
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12
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Hanafy RA, Johnson B, Youssef NH, Elshahed MS. Assessing anaerobic gut fungal diversity in herbivores using D1/D2 large ribosomal subunit sequencing and multi-year isolation. Environ Microbiol 2020; 22:3883-3908. [PMID: 32656919 DOI: 10.1111/1462-2920.15164] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 05/22/2020] [Accepted: 07/10/2020] [Indexed: 11/30/2022]
Abstract
The anaerobic gut fungi (AGF, Neocallimastigomycota) reside in the alimentary tracts of herbivores where they play a central role in the breakdown of plant material. Here, we report on the development of the hypervariable domains D1/D2 of the large ribosomal subunit (D1/D2 LSU) as a barcoding marker for the AGF. We generated a reference D1/D2 LSU database for all cultured AGF genera, as well as the majority of candidate genera encountered in prior internal transcribed spacer 1 (ITS1)-based surveys. Subsequently, a D1/D2 LSU-based diversity survey using long read PacBio SMRT sequencing was conducted on faecal samples from 21 wild and domesticated herbivores. Twenty-eight genera and candidate genera were identified, including multiple novel lineages that were predominantly, but not exclusively, identified in wild herbivores. Association between certain AGF genera and animal lifestyles, or animal host family was observed. Finally, to address the current paucity of AGF isolates, concurrent isolation efforts utilizing multiple approaches to maximize recovery yielded 216 isolates belonging to 12 different genera, several of which have no prior cultured-representatives. Our results establish the utility of D1/D2 LSU and PacBio sequencing for AGF diversity surveys, the culturability of multiple AGF taxa, and demonstrate that wild herbivores represent a yet-untapped reservoir of AGF diversity.
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Affiliation(s)
- Radwa A Hanafy
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Britny Johnson
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Noha H Youssef
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Mostafa S Elshahed
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
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Chernysheva EV, Kashirskaya NN, Demkina EV, Korobov DS, Borisov AV. Thermophilic Microorganisms in Soils as a Result of Ancient Human Activity. Microbiology (Reading) 2019. [DOI: 10.1134/s0026261719050047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Cramm MA, Chakraborty A, Li C, Ruff SE, Jørgensen BB, Hubert CRJ. Freezing Tolerance of Thermophilic Bacterial Endospores in Marine Sediments. Front Microbiol 2019; 10:945. [PMID: 31130935 PMCID: PMC6509201 DOI: 10.3389/fmicb.2019.00945] [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: 01/27/2019] [Accepted: 04/15/2019] [Indexed: 01/18/2023] Open
Abstract
Dormant endospores of anaerobic, thermophilic bacteria found in cold marine sediments offer a useful model for studying microbial biogeography, dispersal, and survival. The dormant endospore phenotype confers resistance to unfavorable environmental conditions, allowing dispersal to be isolated and studied independently of other factors such as environmental selection. To study the resilience of thermospores to conditions relevant for survival in extreme cold conditions, their viability following different freezing treatments was tested. Marine sediment was frozen at either −80°C or −20°C for 10 days prior to pasteurization and incubation at +50°C for 21 days to assess thermospore viability. Sulfate reduction commenced at +50°C following both freezing pretreatments indicating persistence of thermophilic endospores of sulfate-reducing bacteria. The onset of sulfate reduction at +50°C was delayed in −80°C pretreated microcosms, which exhibited more variability between triplicates, compared to −20°C pretreated microcosms and parallel controls that were not frozen in advance. Microbial communities were evaluated by 16S rRNA gene amplicon sequencing, revealing an increase in the relative sequence abundance of thermophilic endospore-forming Firmicutes in all microcosms. Different freezing pretreatments (−80°C and −20°C) did not appreciably influence the shift in overall bacterial community composition that occurred during the +50°C incubations. Communities that had been frozen prior to +50°C incubation showed an increase in the relative sequence abundance of operational taxonomic units (OTUs) affiliated with the class Bacilli, relative to unfrozen controls. These results show that freezing impacts but does not obliterate thermospore populations and their ability to germinate and grow under appropriate conditions. Indeed the majority of the thermospore OTUs detected in this study (21 of 22) could be observed following one or both freezing treatments. These results are important for assessing thermospore viability in frozen samples and following cold exposure such as the very low temperatures that would be encountered during panspermia.
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Affiliation(s)
- Margaret A Cramm
- Geomicrobiology Group, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Anirban Chakraborty
- Geomicrobiology Group, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Carmen Li
- Geomicrobiology Group, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - S Emil Ruff
- Energy Bioengineering Group, Department of Geoscience, University of Calgary, Calgary, AB, Canada
| | - Bo Barker Jørgensen
- Center for Geomicrobiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Casey R J Hubert
- Geomicrobiology Group, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
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Kerfahi D, Tripathi BM, Dong K, Kim M, Kim H, Ferry Slik JW, Go R, Adams JM. From the High Arctic to the Equator: Do Soil Metagenomes Differ According to Our Expectations? MICROBIAL ECOLOGY 2019; 77:168-185. [PMID: 29882154 DOI: 10.1007/s00248-018-1215-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Accepted: 05/28/2018] [Indexed: 06/08/2023]
Abstract
Comparing the functional gene composition of soils at opposite extremes of environmental gradients may allow testing of hypotheses about community and ecosystem function. Here, we were interested in comparing how tropical microbial ecosystems differ from those of polar climates. We sampled several sites in the equatorial rainforest of Malaysia and Brunei, and the high Arctic of Svalbard, Canada, and Greenland, comparing the composition and the functional attributes of soil biota between the two extremes of latitude, using shotgun metagenomic Illumina HiSeq2000 sequencing. Based upon "classical" views of how tropical and higher latitude ecosystems differ, we made a series of predictions as to how various gene function categories would differ in relative abundance between tropical and polar environments. Results showed that in some respects our predictions were correct: the polar samples had higher relative abundance of dormancy related genes, and lower relative abundance of genes associated with respiration, and with metabolism of aromatic compounds. The network complexity of the Arctic was also lower than the tropics. However, in various other respects, the pattern was not as predicted; there were no differences in relative abundance of stress response genes or in genes associated with secondary metabolism. Conversely, CRISPR genes, phage-related genes, and virulence disease and defense genes, were unexpectedly more abundant in the Arctic, suggesting more intense biotic interaction. Also, eukaryote diversity and bacterial diversity were higher in the Arctic of Svalbard compared to tropical Brunei, which is consistent with what may expected from amplicon studies in terms of the higher pH of the Svalbard soil. Our results in some respects confirm expectations of how tropical versus polar nature may differ, and in other respects challenge them.
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Affiliation(s)
- Dorsaf Kerfahi
- Department of Biological Sciences, Seoul National University, Gwanak-Gu, Seoul, 151-747, Republic of Korea
| | - Binu M Tripathi
- Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon, 21990, Republic of Korea
| | - Ke Dong
- Department of Biological Sciences, Seoul National University, Gwanak-Gu, Seoul, 151-747, Republic of Korea
| | - Mincheol Kim
- Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon, 21990, Republic of Korea
| | - Hyoki Kim
- Celemics Inc., 19F, Bldg. A, BYC High City, 131, Gasandigital 1-ro, Geumcheon-gu, Seoul, 153-718, Republic of Korea
| | - J W Ferry Slik
- Faculty of Science, Universiti Brunei Darussalam, Gadong, Brunei Darussalam
| | - Rusea Go
- Department of Biology, Faculty of Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
| | - Jonathan M Adams
- Division of Agrifood and Environment, School of Water, Energy and Environment, Cranfield University, Bedfordshire, MK43 0AL, UK.
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Thakur V, Kumar V, Kumar S, Singh D. Diverse culturable bacterial communities with cellulolytic potential revealed from pristine habitat in Indian trans-Himalaya. Can J Microbiol 2018; 64:798-808. [DOI: 10.1139/cjm-2017-0754] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Pangi–Chamba Himalaya (PCH) region is very pristine, unique, and virgin niche for bioresource exploration. In the current study, for the first time, the bacterial diversity of this region was investigated for potential cellulose degraders. A total of 454 pure bacterial isolates were obtained from diverse sites in the PCH region, and 111 isolates were further selected for 16S rDNA characterization based on ARDRA grouping. The identified bacteria belonged to 28 genera representing four phyla: Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes. Pseudomonas was most abundant genus, followed by Bacillus, Geobacillus, Arthrobacter, Paenibacillus, and Flavobacterium. In addition, six putative novel bacteria (based on 16S rDNA sequence similarity) and thermophiles from non-thermogenic sites were also reported for the first time. Screening for cellulose degradation ability on carboxymethyl cellulose plates revealed that 70.92% of bacteria were cellulolytic. The current study reports diverse bacterial genera (Arthrobacter, Paenibacillus, Chryseobacterium, Pedobacter, Streptomyces, Agromyces, Flavobacterium, and Pseudomonas) with high capacity for cellulose hydrolysis and cellulolytic functionality at wide pH and temperature not previously reported in the literature. Diverse bacterial genera with high cellulolytic activity in broad pH and temperature range provide opportunity to develop a bioprocess for efficient pretreatment of lignocellulosic biomass, which is currently being investigated.
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Affiliation(s)
- Vikas Thakur
- Biotechnology Division, CSIR – Institute of Himalayan Bioresource Technology, Post Box No. 6, Palampur-176 061, Himachal Pradesh, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR – Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, India
| | - Vijay Kumar
- Biotechnology Division, CSIR – Institute of Himalayan Bioresource Technology, Post Box No. 6, Palampur-176 061, Himachal Pradesh, India
| | - Sanjay Kumar
- Biotechnology Division, CSIR – Institute of Himalayan Bioresource Technology, Post Box No. 6, Palampur-176 061, Himachal Pradesh, India
| | - Dharam Singh
- Biotechnology Division, CSIR – Institute of Himalayan Bioresource Technology, Post Box No. 6, Palampur-176 061, Himachal Pradesh, India
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Peculiarities and biotechnological potential of environmental adaptation by Geobacillus species. Appl Microbiol Biotechnol 2018; 102:10425-10437. [PMID: 30310966 DOI: 10.1007/s00253-018-9422-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 09/25/2018] [Accepted: 09/26/2018] [Indexed: 12/21/2022]
Abstract
The genus Geobacillus comprises thermophilic bacilli capable of endospore formation. The members of this genus provide thermostable proteins and can be used in whole cell applications at elevated temperatures; therefore, these organisms are of biotechnological importance. While these applications have been described in previous reviews, the present paper highlights the environmental adaptations and genome diversifications of Geobacillus spp. and their applications in evolutionary-protein engineering. Despite their obligate thermophilic properties, Geobacillus spp. are widely distributed in nature. Because several isolates demonstrate remarkable properties for cell reproduction in their respective niches, they seem to exist not only as endospores but also as vegetative cells in diverse environments. This suggests their excellence in environmental adaptation via genome diversification; in fact, evidence suggests that Geobacillus spp. were derived from Bacillus spp. while diversifying their genomes via horizontal gene transfer. Moreover, when subjected to an environmental stressor, Geobacillus spp. diversify their genomes using inductive mutations and transposable elements to produce derivative cells that are adaptive to the stressor. Notably, inductive mutations in Geobacillus spp. occur more rapidly and frequently than the stress-induced mutagenesis observed in other microorganisms. Owing to this, Geobacillus spp. can efficiently generate mutant genes coding for thermostable enzyme variants from the thermolabile enzyme genes under appropriate selection pressures. This phenomenon provides a new approach to generate thermostable enzymes, termed as thermoadaptation-directed enzyme evolution, thereby expanding the biotechnological potentials of Geobacillus spp. In this review, we have discussed this approach using successful examples and major challenges yet to be addressed.
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Fujii K, Tominaga Y, Okunaka J, Yagi H, Ohshiro T, Suzuki H. Microbial and genomic characterization of Geobacillus thermodenitrificans OS27, a marine thermophile that degrades diverse raw seaweeds. Appl Microbiol Biotechnol 2018; 102:4901-4913. [DOI: 10.1007/s00253-018-8958-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/13/2018] [Accepted: 03/19/2018] [Indexed: 02/03/2023]
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19
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Pervasiveness of UVC254-resistant Geobacillus strains in extreme environments. Appl Microbiol Biotechnol 2018; 102:1869-1887. [DOI: 10.1007/s00253-017-8712-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 12/09/2017] [Accepted: 12/11/2017] [Indexed: 12/11/2022]
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20
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Cordova LT, Cipolla RM, Swarup A, Long CP, Antoniewicz MR. 13C metabolic flux analysis of three divergent extremely thermophilic bacteria: Geobacillus sp. LC300, Thermus thermophilus HB8, and Rhodothermus marinus DSM 4252. Metab Eng 2017; 44:182-190. [PMID: 29037779 PMCID: PMC5845442 DOI: 10.1016/j.ymben.2017.10.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 10/09/2017] [Accepted: 10/11/2017] [Indexed: 01/26/2023]
Abstract
Thermophilic organisms are being increasingly investigated and applied in metabolic engineering and biotechnology. The distinct metabolic and physiological characteristics of thermophiles, including broad substrate range and high uptake rates, coupled with recent advances in genetic tool development, present unique opportunities for strain engineering. However, poor understanding of the cellular physiology and metabolism of thermophiles has limited the application of systems biology and metabolic engineering tools to these organisms. To address this concern, we applied high resolution 13C metabolic flux analysis to quantify fluxes for three divergent extremely thermophilic bacteria from separate phyla: Geobacillus sp. LC300, Thermus thermophilus HB8, and Rhodothermus marinus DSM 4252. We performed 18 parallel labeling experiments, using all singly labeled glucose tracers for each strain, reconstructed and validated metabolic network models, measured biomass composition, and quantified precise metabolic fluxes for each organism. In the process, we resolved many uncertainties regarding gaps in pathway reconstructions and elucidated how these organisms maintain redox balance and generate energy. Overall, we found that the metabolisms of the three thermophiles were highly distinct, suggesting that adaptation to growth at high temperatures did not favor any particular set of metabolic pathways. All three strains relied heavily on glycolysis and TCA cycle to generate key cellular precursors and cofactors. None of the investigated organisms utilized the Entner-Doudoroff pathway and only one strain had an active oxidative pentose phosphate pathway. Taken together, the results from this study provide a solid foundation for future model building and engineering efforts with these and related thermophiles.
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Affiliation(s)
- Lauren T Cordova
- Department of Chemical and Biomolecular Engineering, Metabolic Engineering and Systems Biology Laboratory, University of Delaware, Newark, DE 19716, USA
| | - Robert M Cipolla
- Department of Chemical and Biomolecular Engineering, Metabolic Engineering and Systems Biology Laboratory, University of Delaware, Newark, DE 19716, USA
| | - Adti Swarup
- Department of Chemical and Biomolecular Engineering, Metabolic Engineering and Systems Biology Laboratory, University of Delaware, Newark, DE 19716, USA
| | - Christopher P Long
- Department of Chemical and Biomolecular Engineering, Metabolic Engineering and Systems Biology Laboratory, University of Delaware, Newark, DE 19716, USA
| | - Maciek R Antoniewicz
- Department of Chemical and Biomolecular Engineering, Metabolic Engineering and Systems Biology Laboratory, University of Delaware, Newark, DE 19716, USA.
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Affiliation(s)
- Kristie Tanner
- Darwin Bioprospecting Excellence SL, Paterna, Spain.,I2SysBio (Institute for Integrative Systems Biology), University of Valencia-CSIC, Paterna, Spain
| | | | - Manuel Porcar
- Darwin Bioprospecting Excellence SL, Paterna, Spain.,I2SysBio (Institute for Integrative Systems Biology), University of Valencia-CSIC, Paterna, Spain
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22
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Filippidou S, Wunderlin T, Junier T, Jeanneret N, Dorador C, Molina V, Johnson DR, Junier P. A Combination of Extreme Environmental Conditions Favor the Prevalence of Endospore-Forming Firmicutes. Front Microbiol 2016; 7:1707. [PMID: 27857706 PMCID: PMC5094177 DOI: 10.3389/fmicb.2016.01707] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 10/12/2016] [Indexed: 12/21/2022] Open
Abstract
Environmental conditions unsuitable for microbial growth are the rule rather than the exception in most habitats. In response to this, microorganisms have developed various strategies to withstand environmental conditions that limit active growth. Endospore-forming Firmicutes (EFF) deploy a myriad of survival strategies in order to resist adverse conditions. Like many bacterial groups, they can form biofilms and detect nutrient scarcity through chemotaxis. Moreover, within this paraphyletic group of Firmicutes, ecophysiological optima are diverse. Nonetheless, a response to adversity that delimits this group is the formation of wet-heat resistant spores. These strategies are energetically demanding and therefore might affect the biological success of EFF. Therefore, we hypothesize that abundance and diversity of EFF should be maximized in those environments in which the benefits of these survival strategies offsets the energetic cost. In order to address this hypothesis, geothermal and mineral springs and drillings were selected because in these environments of steep physicochemical gradients, diversified survival strategies may become a successful strategy.We collected 71 samples from geothermal and mineral environments characterized by none (null), single or multiple limiting environmental factors (temperature, pH, UV radiation, and specific mineral composition). To measure success, we quantified EFF gene copy numbers (GCN; spo0A gene) in relation to total bacterial GCN (16S rRNA gene), as well as the contribution of EFF to community composition. The quantification showed that relative GCN for EFF reached up to 20% at sites characterized by multiple limiting environmental factors, whereas it corresponded to less than 1% at sites with one or no limiting environmental factor. Pyrosequencing of the 16S rRNA gene supports a higher contribution of EFF at sites with multiple limiting factors. Community composition suggested a combination of phylotypes for which active growth could be expected, and phylotypes that are most likely in the state of endospores, in all the sites. In summary, our results suggest that diversified survival strategies, including sporulation and metabolic adaptations, explain the biological success of EFF in geothermal and natural springs, and that multiple extreme environmental factors favor the prevalence of EFF.
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Affiliation(s)
- Sevasti Filippidou
- Laboratory of Microbiology, University of Neuchâtel Neuchâtel, Switzerland
| | - Tina Wunderlin
- Laboratory of Microbiology, University of Neuchâtel Neuchâtel, Switzerland
| | - Thomas Junier
- Laboratory of Microbiology, University of NeuchâtelNeuchâtel, Switzerland; Vital-IT group, Swiss Institute of BioinformaticsLausanne, Switzerland
| | - Nicole Jeanneret
- Laboratory of Microbiology, University of Neuchâtel Neuchâtel, Switzerland
| | - Cristina Dorador
- Laboratorio de Complejidad Microbiana y Ecología Funcional and Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de AntofagastaAntofagasta, Chile; Centre for Biotechnology and Bioengineering, CeBiB, University of ChileSantiago, Chile
| | - Veronica Molina
- Departamento de Biología, Facultad de Ciencias Naturales y Exactas. Universidad de Playa Ancha Valparaíso, Chile
| | - David R Johnson
- Department of Environmental Microbiology, Swiss Federal Institute of Aquatic Science and Technology (Eawag) Dübendorf, Switzerland
| | - Pilar Junier
- Laboratory of Microbiology, University of Neuchâtel Neuchâtel, Switzerland
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23
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Bezuidt OK, Pierneef R, Gomri AM, Adesioye F, Makhalanyane TP, Kharroub K, Cowan DA. The Geobacillus Pan-Genome: Implications for the Evolution of the Genus. Front Microbiol 2016; 7:723. [PMID: 27252683 PMCID: PMC4878294 DOI: 10.3389/fmicb.2016.00723] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/02/2016] [Indexed: 11/13/2022] Open
Abstract
The genus Geobacillus is comprised of a diverse group of spore-forming Gram-positive thermophilic bacterial species and is well known for both its ecological diversity and as a source of novel thermostable enzymes. Although the mechanisms underlying the thermophilicity of the organism and the thermostability of its macromolecules are reasonably well understood, relatively little is known of the evolutionary mechanisms, which underlie the structural and functional properties of members of this genus. In this study, we have compared 29 Geobacillus genomes, with a specific focus on the elements, which comprise the conserved core and flexible genomes. Based on comparisons of conserved core and flexible genomes, we present evidence of habitat delineation with specific Geobacillus genomes linked to specific niches. Our analysis revealed that Geobacillus and Anoxybacillus share a high proportion of genes. Moreover, the results strongly suggest that horizontal gene transfer is a major factor deriving the evolution of Geobacillus from Bacillus, with genetic contributions from other phylogenetically distant taxa.
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Affiliation(s)
- Oliver K Bezuidt
- Department of Genetics, Centre for Microbial Ecology and Genomics, University of Pretoria Pretoria, South Africa
| | - Rian Pierneef
- Department of Biochemistry, Centre for Bioinformatics and Computational Biology, University of Pretoria Pretoria, South Africa
| | - Amin M Gomri
- Equipe Métabolites des Extrêmophiles, Laboratoire de Recherche Biotechnologie et Qualité des Aliments, Institut de la Nutrition de l'Alimentation et des Technologies Agro-Alimentaire, Université des Frères Mentouri Constantine, Algeria
| | - Fiyin Adesioye
- Department of Genetics, Centre for Microbial Ecology and Genomics, University of Pretoria Pretoria, South Africa
| | - Thulani P Makhalanyane
- Department of Genetics, Centre for Microbial Ecology and Genomics, University of Pretoria Pretoria, South Africa
| | - Karima Kharroub
- Equipe Métabolites des Extrêmophiles, Laboratoire de Recherche Biotechnologie et Qualité des Aliments, Institut de la Nutrition de l'Alimentation et des Technologies Agro-Alimentaire, Université des Frères Mentouri Constantine, Algeria
| | - Don A Cowan
- Department of Genetics, Centre for Microbial Ecology and Genomics, University of Pretoria Pretoria, South Africa
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Isolation and complete genome sequence of the thermophilic Geobacillus sp. 12AMOR1 from an Arctic deep-sea hydrothermal vent site. Stand Genomic Sci 2016; 11:16. [PMID: 26913091 PMCID: PMC4765119 DOI: 10.1186/s40793-016-0137-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 02/16/2016] [Indexed: 11/17/2022] Open
Abstract
Members of the genus Geobacillus have been isolated from a wide variety of habitats worldwide and are the subject for targeted enzyme utilization in various industrial applications. Here we report the isolation and complete genome sequence of the thermophilic starch-degrading Geobacillus sp. 12AMOR1. The strain 12AMOR1 was isolated from deep-sea hot sediment at the Jan Mayen hydrothermal Vent Site. Geobacillus sp. 12AMOR1 consists of a 3,410,035 bp circular chromosome and a 32,689 bp plasmid with a G + C content of 52 % and 47 %, respectively. The genome comprises 3323 protein-coding genes, 88 tRNA species and 10 rRNA operons. The isolate grows on a suite of sugars, complex polysaccharides and proteinous carbon sources. Accordingly, a versatility of genes encoding carbohydrate-active enzymes (CAZy) and peptidases were identified in the genome. Expression, purification and characterization of an enzyme of the glycoside hydrolase family 13 revealed a starch-degrading capacity and high thermal stability with a melting temperature of 76.4 °C. Altogether, the data obtained point to a new isolate from a marine hydrothermal vent with a large bioprospecting potential.
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25
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Santana MM, Gonzalez JM. High temperature microbial activity in upper soil layers. FEMS Microbiol Lett 2015; 362:fnv182. [DOI: 10.1093/femsle/fnv182] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/25/2015] [Indexed: 01/12/2023] Open
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26
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Cordova LT, Long CP, Venkataramanan KP, Antoniewicz MR. Complete genome sequence, metabolic model construction and phenotypic characterization of Geobacillus LC300, an extremely thermophilic, fast growing, xylose-utilizing bacterium. Metab Eng 2015; 32:74-81. [PMID: 26391740 DOI: 10.1016/j.ymben.2015.09.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 08/26/2015] [Accepted: 09/11/2015] [Indexed: 02/07/2023]
Abstract
We have isolated a new extremely thermophilic fast-growing Geobacillus strain that can efficiently utilize xylose, glucose, mannose and galactose for cell growth. When grown aerobically at 72 °C, Geobacillus LC300 has a growth rate of 2.15 h(-1) on glucose and 1.52 h(-1) on xylose (doubling time less than 30 min). The corresponding specific glucose and xylose utilization rates are 5.55 g/g/h and 5.24 g/g/h, respectively. As such, Geobacillus LC300 grows 3-times faster than E. coli on glucose and xylose, and has a specific xylose utilization rate that is 3-times higher than the best metabolically engineered organism to date. To gain more insight into the metabolism of Geobacillus LC300 its genome was sequenced using PacBio's RS II single-molecule real-time (SMRT) sequencing platform and annotated using the RAST server. Based on the genome annotation and the measured biomass composition a core metabolic network model was constructed. To further demonstrate the biotechnological potential of this organism, Geobacillus LC300 was grown to high cell-densities in a fed-batch culture, where cells maintained a high xylose utilization rate under low dissolved oxygen concentrations. All of these characteristics make Geobacillus LC300 an attractive host for future metabolic engineering and biotechnology applications.
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Affiliation(s)
- Lauren T Cordova
- Department of Chemical and Biomolecular Engineering, Metabolic Engineering and Systems Biology Laboratory, University of Delaware, 150 Academy St, Newark, DE 19716, USA
| | - Christopher P Long
- Department of Chemical and Biomolecular Engineering, Metabolic Engineering and Systems Biology Laboratory, University of Delaware, 150 Academy St, Newark, DE 19716, USA
| | - Keerthi P Venkataramanan
- Department of Chemical and Biomolecular Engineering, Metabolic Engineering and Systems Biology Laboratory, University of Delaware, 150 Academy St, Newark, DE 19716, USA
| | - Maciek R Antoniewicz
- Department of Chemical and Biomolecular Engineering, Metabolic Engineering and Systems Biology Laboratory, University of Delaware, 150 Academy St, Newark, DE 19716, USA.
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27
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Coveley S, Elshahed MS, Youssef NH. Response of the rare biosphere to environmental stressors in a highly diverse ecosystem (Zodletone spring, OK, USA). PeerJ 2015; 3:e1182. [PMID: 26312178 PMCID: PMC4548494 DOI: 10.7717/peerj.1182] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 07/23/2015] [Indexed: 01/09/2023] Open
Abstract
Within highly diverse ecosystems, the majority of bacterial taxa are present in low abundance as members of the rare biosphere. The rationale for the occurrence and maintenance of the rare biosphere, and the putative ecological role(s) and dynamics of its members within a specific ecosystem is currently debated. We hypothesized that in highly diverse ecosystems, a fraction of the rare biosphere acts as a backup system that readily responds to environmental disturbances. We tested this hypothesis by subjecting sediments from Zodletone spring, a sulfide- and sulfur-rich spring in Southwestern OK, to incremental levels of salinity (1, 2, 3, 4, and 10% NaCl), or temperature (28°, 30°, 32°, and 70 °C), and traced the trajectories of rare members of the community in response to these manipulations using 16S rRNA gene analysis. Our results indicate that multiple rare bacterial taxa are promoted from rare to abundant members of the community following such manipulations and that, in general, the magnitude of such recruitment is directly proportional to the severity of the applied manipulation. Rare members that are phylogenetically distinct from abundant taxa in the original sample (unique rare biosphere) played a more important role in the microbial community response to environmental disturbances, compared to rare members that are phylogenetically similar to abundant taxa in the original sample (non-unique rare biosphere). The results emphasize the dynamic nature of the rare biosphere, and highlight its complexity and non-monolithic nature.
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Affiliation(s)
- Suzanne Coveley
- Department of Microbiology and Molecular Genetics, Oklahoma State University , Stillwater, OK , USA
| | - Mostafa S Elshahed
- Department of Microbiology and Molecular Genetics, Oklahoma State University , Stillwater, OK , USA
| | - Noha H Youssef
- Department of Microbiology and Molecular Genetics, Oklahoma State University , Stillwater, OK , USA
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28
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Abstract
The genus Geobacillus comprises a group of Gram-positive thermophilic bacteria, including obligate aerobes, denitrifiers, and facultative anaerobes that can grow over a range of 45-75°C. Originally classified as group five Bacillus spp., strains of Bacillus stearothermophilus came to prominence as contaminants of canned food and soon became the organism of choice for comparative studies of metabolism and enzymology between mesophiles and thermophiles. More recently, their catabolic versatility, particularly in the degradation of hemicellulose and starch, and rapid growth rates have raised their profile as organisms with potential for second-generation (lignocellulosic) biorefineries for biofuel or chemical production. The continued development of genetic tools to facilitate both fundamental investigation and metabolic engineering is now helping to realize this potential, for both metabolite production and optimized catabolism. In addition, this catabolic versatility provides a range of useful thermostable enzymes for industrial application. A number of genome-sequencing projects have been completed or are underway allowing comparative studies. These reveal a significant amount of genome rearrangement within the genus, the presence of large genomic islands encompassing all the hemicellulose utilization genes and a genomic island incorporating a set of long chain alkane monooxygenase genes. With G+C contents of 45-55%, thermostability appears to derive in part from the ability to synthesize protamine and spermine, which can condense DNA and raise its Tm.
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Abstract
The profound influence of microorganisms on human life and global biogeochemical cycles underlines the value of studying the biogeography of microorganisms, exploring microbial genomes and expanding our understanding of most microbial species on Earth: that is, those present at low relative abundance. The detection and subsequent analysis of low-abundance microbial populations—the 'rare biosphere'—have demonstrated the persistence, population dynamics, dispersion and predation of these microbial species. We discuss the ecology of rare microbial populations, and highlight molecular and computational methods for targeting taxonomic 'blind spots' within the rare biosphere of complex microbial communities.
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Perfumo A, Elsaesser A, Littmann S, Foster RA, Kuypers MMM, Cockell CS, Kminek G. Epifluorescence, SEM, TEM and nanoSIMS image analysis of the cold phenotype of Clostridium psychrophilum at subzero temperatures. FEMS Microbiol Ecol 2014; 90:869-82. [PMID: 25319134 DOI: 10.1111/1574-6941.12443] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 10/12/2014] [Accepted: 10/12/2014] [Indexed: 11/27/2022] Open
Abstract
We have applied an image-based approach combining epifluorescence microscopy, electron microscopy and nanoscale secondary ion mass spectrometry (nanoSIMS) with stable isotope probing to examine directly the characteristic cellular features involved in the expression of the cold phenotype in the Antarctic bacterium Clostridium psychrophilum exposed to a temperature range from +5 to -15 °C under anoxic conditions. We observed dramatic morphological changes depending on temperature. At temperatures below -10 °C, cell division was inhibited and consequently filamentous growth predominated. Bacterial cells appeared surrounded by a remarkably thick cell wall and a capsule formed of long exopolysaccharide fibres. Moreover, bacteria were entirely embedded within a dense extracellular matrix, suggesting a role both in cryo-protection and in the cycling of nutrients and genetic material. Strings of extracellular DNA, transient cell membrane permeability and release of membrane vesicles were observed that suggest that evolution via transfer of genetic material may be especially active under frozen conditions. While at -5 °C, the bacterial population was metabolically healthy, at temperatures below -10 °C, most cells showed no sign of active metabolism or the metabolic flux was extremely slowed down; instead of being consumed, carbon was accumulated and stored in intracellular granules as in preparation for a long-term survival.
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Affiliation(s)
- Amedea Perfumo
- European Space Agency, TEC-QI, Noordwijk, The Netherlands
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Zanello P. The competition between chemistry and biology in assembling iron–sulfur derivatives. Molecular structures and electrochemistry. Part II. {[Fe2S2](SγCys)4} proteins. Coord Chem Rev 2014. [DOI: 10.1016/j.ccr.2014.08.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Martinez RJ, Wu CH, Beazley MJ, Andersen GL, Conrad ME, Hazen TC, Taillefert M, Sobecky PA. Microbial community responses to organophosphate substrate additions in contaminated subsurface sediments. PLoS One 2014; 9:e100383. [PMID: 24950228 PMCID: PMC4065101 DOI: 10.1371/journal.pone.0100383] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 05/27/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Radionuclide- and heavy metal-contaminated subsurface sediments remain a legacy of Cold War nuclear weapons research and recent nuclear power plant failures. Within such contaminated sediments, remediation activities are necessary to mitigate groundwater contamination. A promising approach makes use of extant microbial communities capable of hydrolyzing organophosphate substrates to promote mineralization of soluble contaminants within deep subsurface environments. METHODOLOGY/PRINCIPAL FINDINGS Uranium-contaminated sediments from the U.S. Department of Energy Oak Ridge Field Research Center (ORFRC) Area 2 site were used in slurry experiments to identify microbial communities involved in hydrolysis of 10 mM organophosphate amendments [i.e., glycerol-2-phosphate (G2P) or glycerol-3-phosphate (G3P)] in synthetic groundwater at pH 5.5 and pH 6.8. Following 36 day (G2P) and 20 day (G3P) amended treatments, maximum phosphate (PO4(3-)) concentrations of 4.8 mM and 8.9 mM were measured, respectively. Use of the PhyloChip 16S rRNA microarray identified 2,120 archaeal and bacterial taxa representing 46 phyla, 66 classes, 110 orders, and 186 families among all treatments. Measures of archaeal and bacterial richness were lowest under G2P (pH 5.5) treatments and greatest with G3P (pH 6.8) treatments. Members of the phyla Crenarchaeota, Euryarchaeota, Bacteroidetes, and Proteobacteria demonstrated the greatest enrichment in response to organophosphate amendments and the OTUs that increased in relative abundance by 2-fold or greater accounted for 9%-50% and 3%-17% of total detected Archaea and Bacteria, respectively. CONCLUSIONS/SIGNIFICANCE This work provided a characterization of the distinct ORFRC subsurface microbial communities that contributed to increased concentrations of extracellular phosphate via hydrolysis of organophosphate substrate amendments. Within subsurface environments that are not ideal for reductive precipitation of uranium, strategies that harness microbial phosphate metabolism to promote uranium phosphate precipitation could offer an alternative approach for in situ sequestration.
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Affiliation(s)
- Robert J. Martinez
- Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama, United States of America
| | - Cindy H. Wu
- Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Melanie J. Beazley
- Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama, United States of America
| | - Gary L. Andersen
- Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Mark E. Conrad
- Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Terry C. Hazen
- Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Martial Taillefert
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Patricia A. Sobecky
- Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama, United States of America
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Abstract
Recent research has expanded our understanding of microbial community assembly. However, the field of community ecology is inaccessible to many microbial ecologists because of inconsistent and often confusing terminology as well as unnecessarily polarizing debates. Thus, we review recent literature on microbial community assembly, using the framework of Vellend (Q. Rev. Biol. 85:183-206, 2010) in an effort to synthesize and unify these contributions. We begin by discussing patterns in microbial biogeography and then describe four basic processes (diversification, dispersal, selection, and drift) that contribute to community assembly. We also discuss different combinations of these processes and where and when they may be most important for shaping microbial communities. The spatial and temporal scales of microbial community assembly are also discussed in relation to assembly processes. Throughout this review paper, we highlight differences between microbes and macroorganisms and generate hypotheses describing how these differences may be important for community assembly. We end by discussing the implications of microbial assembly processes for ecosystem function and biodiversity.
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Santana MM, Gonzalez JM, Clara MI. Inferring pathways leading to organic-sulfur mineralization in the Bacillales. Crit Rev Microbiol 2014; 42:31-45. [PMID: 24506486 DOI: 10.3109/1040841x.2013.877869] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Microbial organic sulfur mineralization to sulfate in terrestrial systems is poorly understood. The process is often missing in published sulfur cycle models. Studies on microbial sulfur cycling have been mostly centered on transformations of inorganic sulfur, mainly on sulfate-reducing and inorganic sulfur-oxidizing bacteria. Nevertheless, organic sulfur constitutes most sulfur in soils. Recent reports demonstrate that the mobilization of organic-bound-sulfur as sulfate in terrestrial environments occurs preferentially under high temperatures and thermophilic Firmicutes bacteria play a major role in the process, carrying out dissimilative organic-sulfur oxidation. So far, the determinant metabolic reactions of such activity have not been evaluated. Here, in silico analysis was performed on the genomes of sulfate-producing thermophilic genera and mesophilic low-sulfate producers, revealing that highest sulfate production is related to the simultaneous presence of metabolic pathways leading to sulfite synthesis, similar to the ones found in mammalian cells. Those pathways include reverse transsulfuration reactions (tightly associated with methionine cycling), and the presence of aspartate aminotransferases (ATs) with the potential of 3-sulfinoalanine AT and cysteine AT activity, which ultimately leads to sulfite production. Sulfite is oxidized to sulfate by sulfite oxidase, this enzyme is determinant in sulfate synthesis, and it is absent in many mesophiles.
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Zeigler DR. The Geobacillus paradox: why is a thermophilic bacterial genus so prevalent on a mesophilic planet? Microbiology (Reading) 2014; 160:1-11. [DOI: 10.1099/mic.0.071696-0] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The genus Geobacillus comprises endospore-forming obligate thermophiles. These bacteria have been isolated from cool soils and even cold ocean sediments in anomalously high numbers, given that the ambient temperatures are significantly below their minimum requirement for growth. Geobacilli are active in environments such as hot plant composts, however, and examination of their genome sequences reveals that they are endowed with a battery of sensors, transporters and enzymes dedicated to hydrolysing plant polysaccharides. Although they appear to be relatively minor members of the plant biomass-degrading microbial community, Geobacillus bacteria have achieved a significant population with a worldwide distribution, probably in large part due to adaptive features of their spores. First, their morphology and resistance properties enable them to be mobilized in the atmosphere and transported long distances. Second, their longevity, which in theory may be extreme, enables them to lie quiescent but viable for long periods of time, accumulating gradually over time to achieve surprisingly high population densities.
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Affiliation(s)
- Daniel R. Zeigler
- Department of Microbiology, Ohio State University, 484 W 12th Ave, Columbus, OH 43210, USA
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Burgess SA, Flint SH, Lindsay D. Characterization of thermophilic bacilli from a milk powder processing plant. J Appl Microbiol 2013; 116:350-9. [PMID: 24119100 DOI: 10.1111/jam.12366] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 09/18/2013] [Accepted: 10/08/2013] [Indexed: 11/29/2022]
Abstract
AIMS To determine whether strains of Geobacillus stearothermophilus isolated from a milk powder manufacturing plant were different in their ability to form biofilms and produce spores. In addition, this study evaluated whether there were other physiological characteristics that could differentiate these strains. METHODS AND RESULTS Ten G. stearothermophilus strains and one Anoxybacillus species were isolated from a milk powder manufacturing plant. A microtitre plate assay was used to show that these strains differed in their abilities to form biofilms and produce spores. Scanning electron microscopy showed differences in the biofilm morphologies of three of the G. stearothermophilus strains. Biochemical profiling, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and fatty acid profiling further showed that they had distinct characteristics. CONCLUSIONS These G. stearothermophilus strains, isolated from the same environment, showed differences in their ability to form biofilms and produce endospores. Based on the multiple characterization methods used in this study, these strains of G. stearothermophilus isolated from one manufacturing plant are diverse. SIGNIFICANCE AND IMPACT OF THE STUDY Differences in the ability of G. stearothermophilus to form biofilms and produce spores may influence the cleaning method used to control the growth of thermophilic bacilli in a dairy processing environment.
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Affiliation(s)
- S A Burgess
- Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand.,Fonterra Research and Development Centre, Palmerston North, New Zealand
| | - S H Flint
- Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand
| | - D Lindsay
- Fonterra Research and Development Centre, Palmerston North, New Zealand
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Wushke S, Levin DB, Cicek N, Sparling R. Characterization of enriched aerotolerant cellulose-degrading communities for biofuels production using differing selection pressures and inoculum sources. Can J Microbiol 2013; 59:679-83. [PMID: 24102221 DOI: 10.1139/cjm-2013-0430] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ethanol production from direct cellulose fermentation has mainly been described as a strictly anaerobic process. The use of air-tolerant organisms or consortia for this process would reduce the need for prereduction of the medium and also permit continuous feed of aerobic feedstock. To this end, moderately thermophilic (60 °C) consortia of fermentative, cellulolytic bacteria were enriched from 3 distinct environments (manure, marsh, and rotten wood) from a farm in southeast Saskatchewan, Canada. Community phenotypic and metabolic profiles were characterized. Selection methods included direct plating under an aerobic atmosphere and repeated passaging; the methods were designed to select for robust, stable aerotolerant cellulose-degrading communities. Several of the isolated communities exhibited an increase in total cellulose degradation and total ethanol yield when compared with a monoculture of Clostridium thermocellum DSMZ 1237. Owing to stringent selection conditions, low diversity enrichments were found, and many appeared to be binary cultures via density gradient gel electrophoresis analysis. On the basis of 16S rRNA gene sequencing, aerobic conditions selected for a mix of organisms highly related to C. thermocellum and Geobacillus species, while anaerobic conditions led to the development of consortia containing strains related to C. thermocellum with strains from either the genus Geobacillus or the genus Thermoanaerobacter. The presence of a Geobacillus-like species appeared to be a prerequisite for aerotolerance of the cellulolytic enrichments, a highly desired phenotype in lignocellulosic consolidated bioprocessing.
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Affiliation(s)
- Scott Wushke
- a Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
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38
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Brown BP, Brown SR, Senko JM. Microbial communities associated with wet flue gas desulfurization systems. Front Microbiol 2012; 3:412. [PMID: 23226147 PMCID: PMC3510643 DOI: 10.3389/fmicb.2012.00412] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 11/14/2012] [Indexed: 02/01/2023] Open
Abstract
Flue gas desulfurization (FGD) systems are employed to remove SO(x) gasses that are produced by the combustion of coal for electric power generation, and consequently limit acid rain associated with these activities. Wet FGDs represent a physicochemically extreme environment due to the high operating temperatures and total dissolved solids (TDS) of fluids in the interior of the FGD units. Despite the potential importance of microbial activities in the performance and operation of FGD systems, the microbial communities associated with them have not been evaluated. Microbial communities associated with distinct process points of FGD systems at several coal-fired electricity generation facilities were evaluated using culture-dependent and -independent approaches. Due to the high solute concentrations and temperatures in the FGD absorber units, culturable halothermophilic/tolerant bacteria were more abundant in samples collected from within the absorber units than in samples collected from the makeup waters that are used to replenish fluids inside the absorber units. Evaluation of bacterial 16S rRNA genes recovered from scale deposits on the walls of absorber units revealed that the microbial communities associated with these deposits are primarily composed of thermophilic bacterial lineages. These findings suggest that unique microbial communities develop in FGD systems in response to physicochemical characteristics of the different process points within the systems. The activities of the thermophilic microbial communities that develop within scale deposits could play a role in the corrosion of steel structures in FGD systems.
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Affiliation(s)
- Bryan P Brown
- Department of Biology, The University of Akron, Akron OH, USA
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39
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Kormas KA, Smith DC, Edgcomb V, Teske A. Molecular analysis of deep subsurface microbial communities in Nankai Trough sediments (ODP Leg 190, Site 1176). FEMS Microbiol Ecol 2012; 45:115-25. [PMID: 19719622 DOI: 10.1016/s0168-6496(03)00128-4] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract The prokaryotic community inhabiting the deep subsurface sediments in the Forearc Basin of the Nankai Trough southeast of Japan (ODP Site 1176) was analyzed by 16S rDNA sequencing. Sediment samples from 1.15, 51.05, 98.50 and 193.96 m below sea floor (mbsf) harbored highly diverse bacterial communities. The most frequently retrieved clones included members of the Green non-sulfur bacteria whose closest relatives come from deep subsurface environments, a new epsilon-proteobacterial phylotype, and representatives of a cluster of closely related bacterial sequences from hydrocarbon- and methane-rich sediments around the world. Archaeal clones were limited to members of the genus Thermococcus, and were only obtained from the two deepest samples.
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40
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Temperature responses of carbon monoxide and hydrogen uptake by vegetated and unvegetated volcanic cinders. ISME JOURNAL 2012; 6:1558-65. [PMID: 22258097 DOI: 10.1038/ismej.2011.206] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ecosystem succession on a large deposit of volcanic cinders emplaced on Kilauea Volcano in 1959 has resulted in a mosaic of closed-canopy forested patches and contiguous unvegetated patches. Unvegetated and unshaded surface cinders (Bare) experience substantial diurnal temperature oscillations ranging from moderate (16 °C) to extreme (55 °C) conditions. The surface material of adjacent vegetated patches (Canopy) experiences much smaller fluctuations (14-25 °C) due to shading. To determine whether surface material from these sites showed adaptations by carbon monoxide (CO) and hydrogen (H(2)) consumption to changes in ambient temperature regimes accompanying succession, we measured responses of CO and H(2) uptake to short-term variations in temperature and long-term incubations at elevated temperature. Based on its broader temperature optimum and lower activation energy, Canopy H(2) uptake was less sensitive than Bare H(2) uptake to temperature changes. In contrast, Bare and Canopy CO uptake responded similarly to temperature during short-term incubations, indicating no differences in temperature sensitivity. However, during extended incubations at 55 °C, CO uptake increased for Canopy but not Bare material, which indicated that the former was capable of thermal adaptation. H(2) uptake for material from both sites was completely inhibited at 55 °C throughout extended incubations. These results indicated that plant development during succession did not elicit differences in short-term temperature responses for Bare and Canopy CO uptake, in spite of previously reported differences in CO oxidizer community composition, and differences in average daily and extreme temperatures. Differences associated with vegetation due to succession did, however, lead to a notable capacity for thermophilic CO uptake by Canopy but not Bare material.
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41
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Portillo MC, Santana M, Gonzalez JM. Presence and potential role of thermophilic bacteria in temperate terrestrial environments. Naturwissenschaften 2011; 99:43-53. [PMID: 22159635 DOI: 10.1007/s00114-011-0867-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Revised: 11/15/2011] [Accepted: 11/18/2011] [Indexed: 12/01/2022]
Abstract
Organic sulfur and nitrogen are major reservoirs of these elements in terrestrial systems, although their cycling remains to be fully understood. Both sulfur and nitrogen mineralization are directly related to microbial metabolism. Mesophiles and thermophiles were isolated from temperate environments. Thermophilic isolates were classified within the Firmicutes, belonging to the Geobacillus, Brevibacillus, and Ureibacillus genera, and showed optimum growth temperatures between 50°C and 60°C. Sulfate and ammonium produced were higher during growth of thermophiles both for isolated strains and natural bacterial assemblages. They were positively related to organic nutrient load. Temperature also affected the release of sulfate and ammonium by thermophiles. Quantitative, real-time reverse-transcription polymerase chain reaction on environmental samples indicated that the examined thermophilic Firmicutes represented up to 3.4% of the total bacterial community RNA. Temperature measurements during summer days showed values above 40°C for more than 10 h a day in soils from southern Spain. These results support a potential role of thermophilic bacteria in temperate terrestrial environments by mineralizing organic sulfur and nitrogen ruled by the existence and length of warm periods.
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Affiliation(s)
- M C Portillo
- IRNAS-CSIC, Avda. Reina Mercedes 10, Sevilla, 41012, Spain
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42
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Isolation and characterization of N-acylhomoserine lactonase from the thermophilic bacterium, Geobacillus caldoxylosilyticus YS-8. Biosci Biotechnol Biochem 2011; 75:1789-95. [PMID: 21897031 DOI: 10.1271/bbb.110322] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Geobacillus caldoxylosilyticus YS-8, which was isolated from volcanic soil in Indonesia, was found to degrade various N-acylhomoserine lactones (AHLs) with different lengths and acyl side-chain substitutions over a wide temperature range of 30-70 °C. The purified AHL-degrading enzyme showed a single band of 32 kDa, and its N-terminal amino acid sequence was determined to be ANVIKARPKLYVMDN, tentatively suggesting that the AHL-degrading enzyme was AHL lactonase. The AHL-degrading activity of the purified enzyme was maximized at pH 7.5 and 50 °C, and it retained about 50% of its activity even after a heat treatment at 60 °C for 3 h, exhibiting properties consistent with a thermostable enzyme. The mass spectrometric analysis demonstrated that the AHL-degrading enzyme catalyzed lactone ring opening of N-3-oxohexanoyl-L-homoserine lactone and N-hexanoyl-L-homoserine lactone by hydrolyzing the lactones and working as an AHL lactonase.
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Isolation and identification of lipase producing thermophilic Geobacillus sp. SBS-4S: Cloning and characterization of the lipase. J Biosci Bioeng 2011; 111:272-8. [DOI: 10.1016/j.jbiosc.2010.11.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 11/15/2010] [Accepted: 11/19/2010] [Indexed: 11/23/2022]
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44
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Mandic-Mulec I, Prosser JI. Diversity of Endospore-forming Bacteria in Soil: Characterization and Driving Mechanisms. SOIL BIOLOGY 2011. [DOI: 10.1007/978-3-642-19577-8_2] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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45
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Banat IM, Marchant R. Geobacillus Activities in Soil and Oil Contamination Remediation. SOIL BIOLOGY 2011. [DOI: 10.1007/978-3-642-19577-8_13] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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46
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Burgess SA, Lindsay D, Flint SH. Thermophilic bacilli and their importance in dairy processing. Int J Food Microbiol 2010; 144:215-25. [DOI: 10.1016/j.ijfoodmicro.2010.09.027] [Citation(s) in RCA: 206] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Revised: 08/15/2010] [Accepted: 09/25/2010] [Indexed: 11/24/2022]
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47
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Microbial community of a volcanic mudspring in the Philippines as revealed by 16S rDNA sequence analysis and fluorescence in situ hybridization. World J Microbiol Biotechnol 2010. [DOI: 10.1007/s11274-010-0528-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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48
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Perfumo A, Marchant R. Global transport of thermophilic bacteria in atmospheric dust. ENVIRONMENTAL MICROBIOLOGY REPORTS 2010; 2:333-339. [PMID: 23766086 DOI: 10.1111/j.1758-2229.2010.00143.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Aerosols from dust storms generated in the Sahara-Sahel desert area of Africa are transported north over Europe and periodically result in dry dust precipitation in the Mediterranean region. Samples of dust collected in Turkey and Greece following two distinct desert storm events contained viable thermophilic organisms of the genus Geobacillus, namely G. thermoglucosidasius and G. thermodenitrificans, and the recently reclassified Aeribacillus pallidus (formerly Geobacillus pallidus). We present here evidence that African dust storms create an atmospheric bridge between distant geographical regions and that they are also probably the source of thermophilic geobacilli later deposited over northern Europe by rainfall or dust plumes themselves. The same organisms (99% similarity in the 16S rDNA sequence) were found in dust collected in the Mediterranean region and inhabiting cool soils in Northern Ireland. This study also contributes new insights to the taxonomic identification of Geobacillus sp. Attempts to identify these organisms using 16S rRNA gene sequences have revealed that they contain multiple and diverse copies of the ribosomal RNA operon (up to 10 copies with nine different sequences), which dictates care in interpreting data about the systematics of this genus.
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Affiliation(s)
- Amedea Perfumo
- School of Biomedical Sciences and Research Office, University of Ulster, Coleraine, County Londonderry, BT521SA, Northern Ireland, UK
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49
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Soo RM, Wood SA, Grzymski JJ, McDonald IR, Cary SC. Microbial biodiversity of thermophilic communities in hot mineral soils of Tramway Ridge, Mount Erebus, Antarctica. Environ Microbiol 2009; 11:715-28. [PMID: 19278453 DOI: 10.1111/j.1462-2920.2009.01859.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tramway Ridge, located near the summit of Mount Erebus in Antarctica, is probably the most remote geothermal soil habitat on Earth. Steam fumaroles maintain moist, hot soil environments creating extreme local physicochemical differentials. In this study a culture-independent approach combining automated rRNA intergenic spacer analysis (ARISA) and a 16S rRNA gene library was used to characterize soil microbial (Bacterial and Archaeal) diversity along intense physicochemical gradients. Statistical analysis of ARISA data showed a clear delineation between bacterial community structure at sites close to fumaroles and all other sites. Temperature and pH were identified as the primary drivers of this demarcation. A clone library constructed from a high-temperature site led to the identification of 18 novel bacterial operational taxonomic units (OTUs). All 16S rRNA gene sequences were deep branching and distantly (85-93%) related to other environmental clones. Five of the signatures branched with an unknown group between candidate division OP10 and Chloroflexi. Within this clade, sequence similarity was low, suggesting it contains several yet-to-be described bacterial groups. Five archaeal OTUs were obtained and exhibited high levels of sequence similarity (95-97%) with Crenarchaeota sourced from deep-subsurface environments on two distant continents. The novel bacterial assemblage coupled with the unique archaeal affinities reinvigorates the hypotheses that Tramway Ridge organisms are relics of archaic microbial lineages specifically adapted to survive in this harsh environment and that this site may provide a portal to the deep-subsurface biosphere.
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Affiliation(s)
- Rochelle M Soo
- Department of Biological Sciences, University of Waikato, Private Bag, Hamilton, New Zealand
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50
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Weng FY, Chiou CS, Lin PHP, Yang SS. Application of recA and rpoB sequence analysis on phylogeny and molecular identification of Geobacillus species. J Appl Microbiol 2009; 107:452-64. [PMID: 19426278 DOI: 10.1111/j.1365-2672.2009.04235.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AIMS Some Geobacillus species have highly similar 16S rRNA gene sequences, making 16S rDNA sequence analysis-based identification problematic. To overcome this limitation, recA and rpoB sequence analysis was evaluated as an alternative for distinguishing Geobacillus species. METHODS AND RESULTS The phylogram of 16S rRNA gene sequences inferred from the neighbour-joining method showed that nine clusters of Geobacillus species were characterized with bootstrap values >90%. The recA and rpoB sequences of 10 reference strains in clusters V, VIb and VIc were amplified and sequenced using consensus primers. Alignment of recA sequences in clusters V, VIb and VIc revealed three types of recA genes, consistent with the putative amino acid sequences and in vivo recA splicing analysis. The phylogram constructed from rpoB sequences showed more divergence than that constructed from 16S rRNA gene sequences. CONCLUSIONS recA and rpoB sequence analysis differentiated closely-related Geobacillus species and provided direct evidence for reclassifying some species dubiously categorized as Geobacilli. Additionally, this study revealed three types of recA genes in the different Geobacillus species. SIGNIFICANCE AND IMPACT OF THE STUDY This study highlights the advantage of recA and rpoB sequence analysis to supplement 16S rRNA gene sequence analysis for efficient and convenient determination of Geobacillus species.
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Affiliation(s)
- F Y Weng
- Institute of Microbiology and Biochemistry, National Taiwan University, Taipei, Taiwan
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