51
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Appert O, Garcia AR, Frei R, Roduit C, Constancias F, Neuzil-Bunesova V, Ferstl R, Zhang J, Akdis C, Lauener R, Lacroix C, Schwab C. Initial butyrate producers during infant gut microbiota development are endospore formers. Environ Microbiol 2020; 22:3909-3921. [PMID: 32686173 DOI: 10.1111/1462-2920.15167] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 07/09/2020] [Accepted: 07/15/2020] [Indexed: 12/12/2022]
Abstract
The acquisition of the infant gut microbiota is key to establishing a host-microbiota symbiosis. Microbially produced metabolites tightly interact with the immune system, and the fermentation-derived short-chain fatty acid butyrate is considered an important mediator linked to chronic diseases later in life. The intestinal butyrate-forming bacterial population is taxonomically and functionally diverse and includes endospore formers with high transmission potential. Succession, and contribution of butyrate-producing taxa during infant gut microbiota development have been little investigated. We determined the abundance of major butyrate-forming groups and fermentation metabolites in faeces, isolated, cultivated and characterized the heat-resistant cell population, which included endospores, and compared butyrate formation efficiency of representative taxa in batch cultures. The endospore community contributed about 0.001% to total cells, and was mainly composed of the pioneer butyrate-producing Clostridium sensu stricto. We observed an increase in abundance of Faecalibacterium prausnitzii, butyrate-producing Lachnospiraceae and faecal butyrate levels with age that is likely explained by higher butyrate production capacity of contributing taxa compared with Clostridium sensu stricto. Our data suggest that a successional arrangement and an overall increase in abundance of butyrate forming populations occur during the first year of life, which is associated with an increase of intestinal butyrate formation capacity.
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Affiliation(s)
- Olivia Appert
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, ETH Zürich, Zürich, Switzerland
| | - Alejandro Ramirez Garcia
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, ETH Zürich, Zürich, Switzerland
| | - Remo Frei
- Christine Kühne-Center for Allergy Research and Education (CK-CARE), Davos, Switzerland.,Division of Respiratory Medicine, Department of Paediatrics, Inselspital, University of Bern, Bern, Switzerland
| | - Caroline Roduit
- Christine Kühne-Center for Allergy Research and Education (CK-CARE), Davos, Switzerland.,University Children's Hospital Zürich, Zürich, Switzerland.,Children's Hospital St. Gallen, St. Gallen, Switzerland
| | - Florentin Constancias
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, ETH Zürich, Zürich, Switzerland
| | - Vera Neuzil-Bunesova
- Department of Microbiology, Nutrition and Dietetics, Czech University of Life Sciences, Prague, Czech Republic
| | - Ruth Ferstl
- Christine Kühne-Center for Allergy Research and Education (CK-CARE), Davos, Switzerland.,Swiss Institute of Allergy and Asthma Research (SIAF), University of Zürich, Davos, Switzerland
| | - Jianbo Zhang
- Laboratory of Toxicology, Institute of Food, Nutrition and Health, ETH Zürich, Zürich, Switzerland
| | - Cezmi Akdis
- Christine Kühne-Center for Allergy Research and Education (CK-CARE), Davos, Switzerland.,Swiss Institute of Allergy and Asthma Research (SIAF), University of Zürich, Davos, Switzerland
| | - Roger Lauener
- Christine Kühne-Center for Allergy Research and Education (CK-CARE), Davos, Switzerland.,Children's Hospital St. Gallen, St. Gallen, Switzerland
| | - Christophe Lacroix
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, ETH Zürich, Zürich, Switzerland
| | - Clarissa Schwab
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, ETH Zürich, Zürich, Switzerland.,Division of Biological and Chemical Engineering, Aarhus University, Aarhus, Denmark
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52
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"Sporotan" a new fluorescent stain for identifying cryptic spores of Rhodobacter johrii. J Microbiol Methods 2020; 177:106019. [PMID: 32805369 DOI: 10.1016/j.mimet.2020.106019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 07/21/2020] [Accepted: 07/23/2020] [Indexed: 11/27/2022]
Abstract
We propose a new fluorescent stain "sporotan" and staining protocol which aid in the identification of cryptic endospores which are otherwise mistaken as poly-β-hydroxyalkanoate granules.
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53
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Gastrointestinal surgery and the gut microbiome: a systematic literature review. Eur J Clin Nutr 2020; 75:12-25. [PMID: 32661352 DOI: 10.1038/s41430-020-0681-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 06/09/2020] [Accepted: 07/01/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND/OBJECTIVES The impact of gastrointestinal surgery on the profile of the human gut microbiome is not fully understood. This review aimed to identify whether there is a change to the profile of the gut microbiome as a result of gastrointestinal surgery. SUBJECTS/METHODS In August 2018, a systematic literature search was conducted in Medline, PreMedline, Embase, CINAHL and The Cochrane Register of Clinical Trials, identifying and critically appraising studies which investigated changes to gut microbiome pre- and post-gastrointestinal surgery. RESULTS Of 2512 results, 14 studies were included for analysis. All studies reported post-surgical change to the microbiome. In 9 of the 14 studies, prevalence of specific bacteria had significantly changed after surgery. Improved outcome was associated with higher levels of beneficial bacteria and greater microbiome diversity post-surgery. CONCLUSION There were methodological limitations in the included studies leading to uncertainty regarding the impact of gastrointestinal surgery alone on the microbiome profile. An ideal future model for research should encompass case-controlled or cohort design with longer term follow-up in a homogeneous patient group. Future research should seek to clarify the gold standard testing method and standardised timing for post-surgical microbiome sample collection. It is imperative that controls for confounders be put in place to attempt to identify the true association between gastrointestinal surgery and changes to gut microbiome.
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54
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Abstract
The taxonomic and functional diversity inherent to the soil microbiome complicate assessments of the metabolic potential carried out by the community members. An alternative approach is to break down the soil microbiome into reduced-complexity subsets based on metabolic capacities (functional modules) prior to sequencing and analysis. Here, we demonstrate that this approach successfully identified specific phylogenetic and biochemical traits of the soil microbiome that otherwise remained hidden from a more top-down analysis. The soil microbiome represents one of the most complex microbial communities on the planet, encompassing thousands of taxa and metabolic pathways, rendering holistic analyses computationally intensive and difficult. Here, we developed an alternative approach in which the complex soil microbiome was broken into components (“functional modules”), based on metabolic capacities, for individual characterization. We hypothesized that reproducible, low-complexity communities that represent functional modules could be obtained through targeted enrichments and that, in combination, they would encompass a large extent of the soil microbiome diversity. Enrichments were performed on a starting soil inoculum with defined media based on specific carbon substrates, antibiotics, alternative electron acceptors under anaerobic conditions, or alternative growing conditions reflective of common field stresses. The resultant communities were evaluated through 16S rRNA amplicon sequencing. Less permissive modules (anaerobic conditions, complex polysaccharides, and certain stresses) resulted in more distinct community profiles with higher richness and more variability between replicates, whereas modules with simple substrates were dominated by fewer species and were more reproducible. Collectively, approximately 27% of unique taxa present in the liquid soil extract control were found across functional modules. Taxa that were underrepresented or undetected in the source soil were also enriched across the modules. Metatranscriptomic analyses were carried out on a subset of the modules to investigate differences in functional gene expression. These results demonstrate that by dissecting the soil microbiome into discrete components it is possible to obtain a more comprehensive view of the soil microbiome and its biochemical potential than would be possible using more holistic analyses.
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55
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Given C, Häikiö E, Kumar M, Nissinen R. Tissue-Specific Dynamics in the Endophytic Bacterial Communities in Arctic Pioneer Plant Oxyria digyna. FRONTIERS IN PLANT SCIENCE 2020; 11:561. [PMID: 32528486 PMCID: PMC7247849 DOI: 10.3389/fpls.2020.00561] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 04/15/2020] [Indexed: 06/11/2023]
Abstract
The rapid developments in the next-generation sequencing methods in the recent years have provided a wealth of information on the community structures and functions of endophytic bacteria. However, the assembly processes of these communities in different plant tissues are still currently poorly understood, especially in wild plants in natural settings. The aim of this study was to compare the composition of endophytic bacterial communities in leaves and roots of arcto-alpine pioneer plant Oxyria digyna, and investigate, how plant tissue (leaf or root) or plant origin affect the community assembly. To address this, we planted micropropagated O. digyna plants with low bacterial load (bait plants) in experimental site with native O. digyna population, in the Low Arctic. The endophytic bacterial community structures in the leaves and roots of the bait plants were analyzed after one growing season and one year in the field, and compared to those of the wild plants growing at the same site. 16S rRNA gene targeted sequencing revealed that endophytic communities in the roots were more diverse than in the leaves, and the diversity in the bait plants increased in the field, and was highest in the wild plants. Both tissue type and plant group had strong impact on the endophytic bacterial community structures. Firmicutes were highly abundant in the leaf communities of both plant types. Proteobacteria and Bacteroidetes were more abundant in the roots, albeit with different relative abundances in different plant groups. The community structures in the bait plants changed in the field over time, and increasingly resembled the wild plant endophytic communities. This was due to the changes in the relative abundances of several bacterial taxa, as well as species acquisition in the field, but with no species turnover. Several OTUs that were acquired by the bait plants in the field and represent phosphate solubilizing and diazotrophic bacterial taxa, suggesting major role in nutrient acquisition of these bacteria for this nonmycorrhizal plant, thriving in the nutrient poor arctic soils.
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Affiliation(s)
- Cindy Given
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Elina Häikiö
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
| | - Manoj Kumar
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Riitta Nissinen
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
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56
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Zagrodnik R, Duber A, Łężyk M, Oleskowicz-Popiel P. Enrichment Versus Bioaugmentation-Microbiological Production of Caproate from Mixed Carbon Sources by Mixed Bacterial Culture and Clostridium kluyveri. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:5864-5873. [PMID: 32267683 PMCID: PMC7588035 DOI: 10.1021/acs.est.9b07651] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Chain elongation is a process that produces medium chain fatty acids such as caproic acid, which is one of the promising products of the carboxylate platform. This study analyzed the impact of bioaugmentation of heat-treated anaerobic digester sludge with Clostridium kluyveri (AS + Ck) on caproic acid production from a mixed substrate (lactose, lactate, acetate, and ethanol). It was compared with processes initiated with non-augmented heat-treated anaerobic digester sludge (AS) and mono-culture of C. kluyveri (Ck). Moreover, stability of the chain elongation process was evaluated by performing repeated batch experiments. All bacterial cultures demonstrated efficient caproate production in the first batch cycle. After 18 days, caproate concentration reached 9.06 ± 0.43, 7.86 ± 0.38, and 7.67 ± 0.37 g/L for AS, Ck, and AS + Ck cultures, respectively. In the second cycle, AS microbiome was enriched toward caproate production and showed the highest caproate concentration of 11.44 ± 0.47 g/L. On the other hand, bioaugmented culture showed the lowest caproate production in the second cycle (4.10 ± 0.30 g/L). Microbiome analysis in both AS and AS + Ck culture samples indicated strong enrichment toward the anaerobic order of Clostridia. Strains belonging to genera Sporanaerobacter, Paraclostridium, Haloimpatiens, Clostridium, and Bacillus were dominating in the bioreactors.
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Affiliation(s)
- Roman Zagrodnik
- Faculty
of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego
8, 61-614 Poznan, Poland
| | - Anna Duber
- Water
Supply and Bioeconomy Division, Faculty of Environmental Engineering
and Energy, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland
| | - Mateusz Łężyk
- Water
Supply and Bioeconomy Division, Faculty of Environmental Engineering
and Energy, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland
| | - Piotr Oleskowicz-Popiel
- Water
Supply and Bioeconomy Division, Faculty of Environmental Engineering
and Energy, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland
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57
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Dittoe DK, Barabote RD, Rothrock MJ, Ricke SC. Assessment of a Potential Role of Dickeya dadantii DSM 18020 as a Pectinase Producer for Utilization in Poultry Diets Based on in silico Analyses. Front Microbiol 2020; 11:751. [PMID: 32390987 PMCID: PMC7191031 DOI: 10.3389/fmicb.2020.00751] [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: 05/31/2019] [Accepted: 03/30/2020] [Indexed: 01/17/2023] Open
Abstract
Currently, the poultry industry has been faced with consumer pressure to utilize only vegetable feedstuffs in poultry diets, eliminate antibiotics from poultry production, and rear poultry in free range systems. To maintain current production standards, the industry must determine ways to enhance nutrient uptake and utilization further. One possible solution is the supplementation of pectinase, an enzyme that degrades pectin within the cell walls of plants, in poultry diets. Therefore, the objective of the current study was to determine the potential role of a pectinase producer, Dickeya dadantii DSM 18020, as a commercially utilized pectinase producer in poultry diets against other known pectinase producers, in silico. In the current study, whole genomes of Dickeya dadantii DSM 18020 (Dd18020), D. dadantii 3937 (Dd3937), D. solani IPO 2222 (Ds2222), Bacillus halodurans C-125 (BhC125), and B. subtilis subsp. subtilis str. 168 (Bs168) were compared using bioinformatic approaches to compare the chromosomal genome size, GC content, protein coding genes (CDS), total genes, average protein length (a.a.) and determine the predicted metabolic pathways, predicted pectin degrading enzymes, and pectin-degradation pathways across pectinase producers. Due to insufficient information surrounding the genome of Dd18020 (lack of annotation), the genome of Dd3937, a 99% identical genome to Dd18020, was utilized to compare pectinase-associated enzymes and pathways. The results from the current study demonstrated that Dd3937 possessed the most significant proportion of pathways presented and the highest number of pathways related to degradation, assimilation, and utilization of pectin. Also, Dd18020 exhibited a high number of pectinase-related enzymes. Both Dd3937 and Dd2222 shared the pectin degradation I pathway via the EC 3.1.1.11, EC 3.2.1.82, and EC 4.2.2.- enzymes, but did not share this pathway with either Bacillus species. In conclusion, Dd18020 demonstrated the genetic potential to produce multiple pectinase enzymes that could be beneficial to the degradation of pectin in poultry diets. However, for Dd18020 to become a commercially viable enzyme producer for the poultry industry, further research quantifying the pectinase production in vitro and determining the stability of the produced pectinases during feed manufacturing are necessary.
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Affiliation(s)
- Dana K Dittoe
- Department of Food Science and Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
| | - Ravi D Barabote
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, United States
| | - Michael J Rothrock
- Egg Safety and Quality Research Unit, U.S. National Poultry Research Center, United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Athens, GA, United States
| | - Steven C Ricke
- Department of Food Science and Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
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58
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Leung PM, Bay SK, Meier DV, Chiri E, Cowan DA, Gillor O, Woebken D, Greening C. Energetic Basis of Microbial Growth and Persistence in Desert Ecosystems. mSystems 2020; 5:e00495-19. [PMID: 32291352 PMCID: PMC7159902 DOI: 10.1128/msystems.00495-19] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Microbial life is surprisingly abundant and diverse in global desert ecosystems. In these environments, microorganisms endure a multitude of physicochemical stresses, including low water potential, carbon and nitrogen starvation, and extreme temperatures. In this review, we summarize our current understanding of the energetic mechanisms and trophic dynamics that underpin microbial function in desert ecosystems. Accumulating evidence suggests that dormancy is a common strategy that facilitates microbial survival in response to water and carbon limitation. Whereas photoautotrophs are restricted to specific niches in extreme deserts, metabolically versatile heterotrophs persist even in the hyper-arid topsoils of the Atacama Desert and Antarctica. At least three distinct strategies appear to allow such microorganisms to conserve energy in these oligotrophic environments: degradation of organic energy reserves, rhodopsin- and bacteriochlorophyll-dependent light harvesting, and oxidation of the atmospheric trace gases hydrogen and carbon monoxide. In turn, these principles are relevant for understanding the composition, functionality, and resilience of desert ecosystems, as well as predicting responses to the growing problem of desertification.
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Affiliation(s)
- Pok Man Leung
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
- Department of Microbiology, Biomedicine Discovery Institute, Clayton, Victoria, Australia
| | - Sean K Bay
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
- Department of Microbiology, Biomedicine Discovery Institute, Clayton, Victoria, Australia
| | - Dimitri V Meier
- Division of Microbial Ecology, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Eleonora Chiri
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
- Department of Microbiology, Biomedicine Discovery Institute, Clayton, Victoria, Australia
| | - Don A Cowan
- Centre for Microbial Ecology and Genomics, University of Pretoria, Hatfield, Pretoria, South Africa
| | - Osnat Gillor
- Zuckerberg Institute for Water Research, Blaustein Institutes for Desert Research, Ben Gurion University of the Negev, Sde Boker, Israel
| | - Dagmar Woebken
- Division of Microbial Ecology, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Chris Greening
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
- Department of Microbiology, Biomedicine Discovery Institute, Clayton, Victoria, Australia
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59
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Ramos-Silva P, Serrano M, Henriques AO. From Root to Tips: Sporulation Evolution and Specialization in Bacillus subtilis and the Intestinal Pathogen Clostridioides difficile. Mol Biol Evol 2020; 36:2714-2736. [PMID: 31350897 PMCID: PMC6878958 DOI: 10.1093/molbev/msz175] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Bacteria of the Firmicutes phylum are able to enter a developmental pathway that culminates with the formation of highly resistant, dormant endospores. Endospores allow environmental persistence, dissemination and for pathogens, are also infection vehicles. In both the model Bacillus subtilis, an aerobic organism, and in the intestinal pathogen Clostridioides difficile, an obligate anaerobe, sporulation mobilizes hundreds of genes. Their expression is coordinated between the forespore and the mother cell, the two cells that participate in the process, and is kept in close register with the course of morphogenesis. The evolutionary mechanisms by which sporulation emerged and evolved in these two species, and more broadly across Firmicutes, remain largely unknown. Here, we trace the origin and evolution of sporulation using the genes known to be involved in the process in B. subtilis and C. difficile, and estimating their gain-loss dynamics in a comprehensive bacterial macroevolutionary framework. We show that sporulation evolution was driven by two major gene gain events, the first at the base of the Firmicutes and the second at the base of the B. subtilis group and within the Peptostreptococcaceae family, which includes C. difficile. We also show that early and late sporulation regulons have been coevolving and that sporulation genes entail greater innovation in B. subtilis with many Bacilli lineage-restricted genes. In contrast, C. difficile more often recruits new sporulation genes by horizontal gene transfer, which reflects both its highly mobile genome, the complexity of the gut microbiota, and an adjustment of sporulation to the gut ecosystem.
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Affiliation(s)
- Paula Ramos-Silva
- Instituto Gulbenkian de Ciência, Oeiras, Portugal.,Marine Biodiversity Group, Naturalis Biodiversity Center, Leiden, The Netherlands
| | - Mónica Serrano
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Adriano O Henriques
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
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60
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Van Goethem MW, Swenson TL, Trubl G, Roux S, Northen TR. Characteristics of Wetting-Induced Bacteriophage Blooms in Biological Soil Crust. mBio 2019; 10:e02287-19. [PMID: 31848272 PMCID: PMC6918073 DOI: 10.1128/mbio.02287-19] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 11/07/2019] [Indexed: 12/15/2022] Open
Abstract
Biological soil crusts (biocrusts) are photosynthetic "hot spots" in deserts and cover ∼12% of the Earth's terrestrial surface, and yet they face an uncertain future given expected shifts in rainfall events. Laboratory wetting of biocrust communities is known to cause a bloom of Firmicutes which rapidly become dominant community members within 2 days after emerging from a sporulated state. We hypothesized that their bacteriophages (phages) would respond to such a dramatic increase in their host's abundance. In our experiment, wetting caused Firmicutes to bloom and triggered a significant depletion of cyanobacterial diversity. We used genome-resolved metagenomics to link phage to their hosts and found that the bloom of the genus Bacillus correlated with a dramatic increase in the number of Caudovirales phages targeting these diverse spore-formers (r = 0.762). After 2 days, we observed dramatic reductions in the relative abundances of Bacillus, while the number of Bacillus phages continued to increase, suggestive of a predator-prey relationship. We found predicted auxiliary metabolic genes (AMGs) associated with sporulation in several Caudovirales genomes, suggesting that phages may influence and even benefit from sporulation dynamics in biocrusts. Prophage elements and CRISPR-Cas repeats in Firmicutes metagenome-assembled genomes (MAGs) provide evidence of recent infection events by phages, which were corroborated by mapping viral contigs to their host MAGs. Combined, these findings suggest that the blooming Firmicutes become primary targets for biocrust Caudovirales phages, consistent with the classical "kill-the-winner" hypothesis.IMPORTANCE This work forms part of an overarching research theme studying the effects of a changing climate on biological soil crust (biocrust) in the Southwestern United States. To our knowledge, this study was the first to characterize bacteriophages in biocrust and offers a view into the ecology of phages in response to a laboratory wetting experiment. The phages identified here represent lineages of Caudovirales, and we found that the dynamics of their interactions with their Firmicutes hosts explain the collapse of a bacterial bloom that was induced by wetting. Moreover, we show that phages carried host-altering metabolic genes and found evidence of proviral infection and CRISPR-Cas repeats within host genomes. Our results suggest that phages exert controls on population density by lysing dominant bacterial hosts and that they further impact biocrust by acquiring host genes for sporulation. Future research should explore how dominant these phages are in other biocrust communities and quantify how much the control and lysis of blooming populations contributes to nutrient cycling in biocrusts.
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Affiliation(s)
- Marc W Van Goethem
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Tami L Swenson
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Gareth Trubl
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, USA
| | - Simon Roux
- DOE Joint Genome Institute, Walnut Creek, California, USA
| | - Trent R Northen
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
- DOE Joint Genome Institute, Walnut Creek, California, USA
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61
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Biodiversity of epiphytic Pseudomonas strains isolated from leaves of pepper and lettuce. Biologia (Bratisl) 2019. [DOI: 10.2478/s11756-019-00392-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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62
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Mishra S, Rastogi YP, Jabin S, Kaur P, Amir M, Khatun S. A deep learning ensemble for function prediction of hypothetical proteins from pathogenic bacterial species. Comput Biol Chem 2019; 83:107147. [PMID: 31698160 DOI: 10.1016/j.compbiolchem.2019.107147] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 10/05/2019] [Accepted: 10/09/2019] [Indexed: 01/06/2023]
Abstract
Protein function prediction is a crucial task in the post-genomics era due to their diverse irreplaceable roles in a biological system. Traditional methods involved cost-intensive and time-consuming molecular biology techniques but they proved to be ineffective after the outburst of sequencing data through the advent of cost-effective and advanced sequencing techniques. To manage the pace of annotation with that of data generation, there is a shift to computational approaches which are based on homology, sequence and structure-based features, protein-protein interaction networks, phylogenetic profiles, and physicochemical properties, etc. A combination of these features has proven to be promising for protein function prediction in terms of improving prediction accuracy. In the present work, we have employed a combination of features based on sequence, physicochemical property, subsequence and annotation features with a total of 9890 features extracted and/or calculated for 171,212 reviewed prokaryotic proteins of 9 bacterial phyla from UniProtKB, to train a supervised deep learning ensemble model with the aim to categorize a bacterial hypothetical/unreviewed protein's function into 1739 GO terms as functional classes. The proposed system being fully dedicated to bacterial organisms is a novel attempt amongst various existing machine learning based protein function prediction systems based on mixed organisms. Experimental results demonstrate the success of the proposed deep learning ensemble model based on deep neural network method with F1 measure of 0.7912 on the prepared Test dataset 1 of reviewed proteins.
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Affiliation(s)
- Sarthak Mishra
- Department of Computer Science, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, Delhi, India
| | - Yash Pratap Rastogi
- Department of Computer Science, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, Delhi, India
| | - Suraiya Jabin
- Department of Computer Science, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, Delhi, India.
| | - Punit Kaur
- Department of Biophysics, All India Institute of Medical Sciences (AIIMS), New Delhi, 110 029, Delhi, India
| | - Mohammad Amir
- Department of Computer Science, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, Delhi, India
| | - Shabnam Khatun
- Department of Computer Science, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, Delhi, India
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63
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Tamiev D, Lantz A, Vezeau G, Salis H, Reuel NF. Controlling Heterogeneity and Increasing Titer from Riboswitch-Regulated Bacillus subtilis Spores for Time-Delayed Protein Expression Applications. ACS Synth Biol 2019; 8:2336-2346. [PMID: 31490060 DOI: 10.1021/acssynbio.9b00163] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Sporulated cells have potential as time-delayed expression chassis of proteins for applications such as "on-demand" biologics production, whole cell biosensors, or oral vaccines. However, the desired attributes of high expression rates and low product variances are difficult to maintain from germinated spores. In this work, we study the effect of an integrating vs theta-replicating plasmid in a wild-type Bacillus subtilis and two PolY mutants. The cells were engineered to produce a fluorescent reporter protein (RFP) under the control of a riboswitch activated by theophylline. This allowed for greater sensitivity to point mutations. The fluorescence and cell-growth curves were fit with a custom kinetic model, and a peak kinetic rate (LKPmax) was extracted for each clonal population (n = 30 for all cell, vector, and growth combinations). Plasmid-based expression yields higher (8.7×) expression rates because of an increased copy number of the expression cassette (10× over integrated). The variance of LKPmax values increased 2.1× after sporulation for the wild-type strain. This increase in variance from sporulation is very similar to what is observed with UV exposure. This effect can be partially mitigated by the use of PolY knockouts observed in suspended cell growths and adherent biofilms.
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Affiliation(s)
- Denis Tamiev
- Department of Biochemistry Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - Alyssa Lantz
- Department of Biochemistry Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - Grace Vezeau
- Department of Chemical Engineering, Agricultural and Biological Engineering, Penn State University, University Park, Pennsylvania 16802, United States
| | - Howard Salis
- Department of Chemical Engineering, Agricultural and Biological Engineering, Penn State University, University Park, Pennsylvania 16802, United States
| | - Nigel F. Reuel
- Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, United States
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Shen F, Zheng Y, Niu M, Zhou F, Wu Y, Wang J, Zhu T, Wu Y, Wu Z, Hu M, Zhu T. Characteristics of biological particulate matters at urban and rural sites in the North China Plain. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 253:569-577. [PMID: 31330349 DOI: 10.1016/j.envpol.2019.07.033] [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: 05/21/2019] [Revised: 07/05/2019] [Accepted: 07/06/2019] [Indexed: 06/10/2023]
Abstract
Depending on their concentrations, sizes, and types, particulate matters of biological origins (bioPM) significantly affect human health. However, for different air environments, they are not well characterized and can vary considerably. As an example, we investigated the bioPM differences at an urban (Beijing) site and a rural (Wangdu) site in the North China Plain (NCP) using an online monitoring instrument, an ultraviolet aerodynamic particle sizer (UV-APS), the limulus amebocyte lysate (LAL) assay, and a high-throughput sequencing method. Generally, lower concentrations of viable bioPM (hourly mean: 1.3 × 103 ± 1.6 × 103 m-3) and endotoxin (0.66 ± 0.16 EU/m3) in Beijing were observed compared to viable bioPM (0.79 × 105 ± 1.4 × 105 m-3) and endotoxin (15.1 ± 23.96 EU/m3) at the Wangdu site. The percentage of viable bioPM number concentration in the total PM was 3.1% in Beijing and 6.4% in Wangdu. Approximately 80% of viable bioPM was found to be in the range from 1 to 2.5 μm. Nevertheless, the size distribution patterns for viable bioPM at the Beijing and Wangdu sites differed and were affected by PM pollution, leading to distinct lung deposition profiles. Moreover, the distinct diurnal variations in viable bioPM on clean days were dimmed by the PM pollution at both sites. Distinct bacterial community structures were found in the air from the Beijing and Wangdu sites. The bacterial community in urban Beijing was dominated by genus Lactococcus (49.5%) and Pseudomonas (15.1%), while the rural Wangdu site was dominated by Enterococcus (65%) and Paenibacillus (10%). Human-derived genera, including Myroides, Streptococcus, Propionibacterium, Dietzia, Helcococcus, and Facklamia, were higher in Beijing, suggesting bacterial emission from humans in the urban air environment. Our results show that different air harbors different biological species, and people residing in different environments thus could have very different biological particle exposure.
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Affiliation(s)
- Fangxia Shen
- School of Space and Environment, Beihang University, Beijing, 102206, China.
| | - Yunhao Zheng
- College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China; Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Mutong Niu
- School of Space and Environment, Beihang University, Beijing, 102206, China
| | - Feng Zhou
- School of Space and Environment, Beihang University, Beijing, 102206, China
| | - Yan Wu
- School of Environmental Science and Engineering, Shandong University, Qingdao, 250100, China
| | - Junxia Wang
- College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Tong Zhu
- College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Yusheng Wu
- College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Zhijun Wu
- College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Min Hu
- College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Tianle Zhu
- School of Space and Environment, Beihang University, Beijing, 102206, China
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65
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Wang L, Yang J, Huang Y, Liu Q, Xu Y, Piao X, Wise MJ. Systematic Analysis of Metabolic Pathway Distributions of Bacterial Energy Reserves. G3 (BETHESDA, MD.) 2019; 9:2489-2496. [PMID: 31151997 PMCID: PMC6686919 DOI: 10.1534/g3.119.400123] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 05/28/2019] [Indexed: 01/08/2023]
Abstract
Previous bioinformatics studies have linked gain or loss of energy reserves with host-pathogen interactions and bacterial virulence based on a comparatively small number of bacterial genomes or proteomes. Thus, understanding the theoretical distribution patterns of energy reserves across bacterial species could provide a shortcut route to look into bacterial lifestyle and physiology. So far, five major energy reserves have been identified in bacteria due to their capacity to support bacterial persistence under nutrient deprivation conditions. These include polyphosphate (polyP), glycogen, wax ester (WE), triacylglycerol (TAG), and polyhydroxyalkanoates (PHAs). Although the enzymes related with metabolism of energy reserves are well understood, there is a lack of systematic investigations into the distribution of bacterial energy reserves from an evolutionary point of view. In this study, we sourced 8282 manually reviewed bacterial reference proteomes and combined a set of hidden Markov sequence models (HMMs) to search homologs of key enzymes related with the metabolism of energy reserves. Our results revealed that specific pathways like trehalose-related glycogen metabolism and enzymes such as wax ester synthase/acyl-CoA:diacylglycerol acyltransferase (WS/DGAT) are mainly restricted within specific types of bacterial groups, which provides evolutionary insights into the understanding of their origins and functions. In addition, the study also confirms that loss of energy reserves like polyP metabolism absence in Mollicutes is correlated with bacterial genome reduction. Through this analysis, a clearer picture about the metabolism of energy reserves in bacteria is presented, which could serve as a guide for further theoretical and experimental analyses of bacterial energy metabolism.
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Affiliation(s)
- Liang Wang
- Department of Bioinformatics, School of Medical Informatics,
- Jiangsu Key Lab of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu Province, 221000, China
| | - Jianye Yang
- Department of Bioinformatics, School of Medical Informatics
| | - Yue Huang
- Department of Bioinformatics, School of Medical Informatics
| | - Qinghua Liu
- Jiangsu Key Lab of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu Province, 221000, China
| | - Yaping Xu
- Department of Bioinformatics, School of Medical Informatics
| | - Xue Piao
- Department of Bioinformatics, School of Medical Informatics
- School of Information and Control Engineering, China University of Mining and Technology, Xuzhou, Jiangsu, 221116, China
| | - Michael J Wise
- Department of Computer Science and Software Engineering, and
- The Marshall Centre for Infectious Diseases Research and Training, University of Western Australia, Perth 6009, WA, Australia
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66
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van Gestel J, Ackermann M, Wagner A. Microbial life cycles link global modularity in regulation to mosaic evolution. Nat Ecol Evol 2019; 3:1184-1196. [PMID: 31332330 DOI: 10.1038/s41559-019-0939-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 06/03/2019] [Indexed: 11/09/2022]
Abstract
Microbes are exposed to changing environments, to which they can respond by adopting various lifestyles such as swimming, colony formation or dormancy. These lifestyles are often studied in isolation, thereby giving a fragmented view of the life cycle as a whole. Here, we study lifestyles in the context of this whole. We first use machine learning to reconstruct the expression changes underlying life cycle progression in the bacterium Bacillus subtilis, based on hundreds of previously acquired expression profiles. This yields a timeline that reveals the modular organization of the life cycle. By analysing over 380 Bacillales genomes, we then show that life cycle modularity gives rise to mosaic evolution in which life stages such as motility and sporulation are conserved and lost as discrete units. We postulate that this mosaic conservation pattern results from habitat changes that make these life stages obsolete or detrimental. Indeed, when evolving eight distinct Bacillales strains and species under laboratory conditions that favour colony growth, we observe rapid and parallel losses of the sporulation life stage across species, induced by mutations that affect the same global regulator. We conclude that a life cycle perspective is pivotal to understanding the causes and consequences of modularity in both regulation and evolution.
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Affiliation(s)
- Jordi van Gestel
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Zürich, Switzerland. .,Swiss Institute of Bioinformatics, Lausanne, Switzerland. .,Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland. .,Department of Environmental Microbiology, Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf, Switzerland.
| | - Martin Ackermann
- Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland.,Department of Environmental Microbiology, Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf, Switzerland
| | - Andreas Wagner
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Zürich, Switzerland. .,Swiss Institute of Bioinformatics, Lausanne, Switzerland. .,The Santa Fe Institute, Santa Fe, NM, USA.
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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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68
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Phylogenetic diversity of aerobic spore-forming Bacillalles isolated from Brazilian soils. Int Microbiol 2019; 22:511-520. [PMID: 31049768 DOI: 10.1007/s10123-019-00080-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 03/20/2019] [Accepted: 04/15/2019] [Indexed: 10/26/2022]
Abstract
The phylum Firmicutes comprises seven classes where most species are either aerobic or anaerobic endospore former. Inside Firmicutes, species allocated in the genus Bacillus and related genera are collectively named aerobic endospore-forming bacteria (AEFB), and the soil is their major reservoir. AEFB have great importance in health, agriculture, and biotechnology although the more studied species are Bacillus subtilis and the human pathogens Bacillus cereus and Bacillus anthracis. AEFB have great importance in health, agriculture, and biotechnology; although the knowledge about these organisms is based on few species, notably, Bacillus subtilis, Bacillus cereus, and Bacillus anthracis. In this work, we generated partial 16S rRNA gene sequences of both strands of 192 AEFB strains isolated from soils of Distrito Federal, Brazil (SDF strains). The resulting consensus sequences were used to obtain taxonomic assignment and establish the phylogenetic relationships among these strains. Through this approach, we could observe that classified SDF strains were distributed among genera Bacillus (169 strains; 88.02%), Paenibacillus (11; 5.73%), Lysinibacillus (6; 3.13%), Brevibacillus (4; 2.08%), Terribacillus (1; 0.52%), and Rummeliibacillus (1; 0.52%). Phylogenetic trees revealed these 192 SDF strains can be segregated into eight groups spanning families Bacillaceae and Paenibacillaceae belonging to the order Bacillales. To expand the knowledge about the diversity of these SDF strains, further studies regarding characterization with different methodologies are underway.
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69
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Cipriano MAP, Suleiman AKA, da Silveira APD, do Carmo JB, Kuramae EE. Bacterial community composition and diversity of two different forms of an organic residue of bioenergy crop. PeerJ 2019; 7:e6768. [PMID: 31024771 PMCID: PMC6475576 DOI: 10.7717/peerj.6768] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 03/12/2019] [Indexed: 11/20/2022] Open
Abstract
The use of residue of sugarcane ethanol industry named vinasse in fertirrigation is an established and widespread practice in Brazil. Both non-concentrated vinasse (NCV) and concentrated vinasse (CV) are used in fertirrigation, particularly to replace the potassium fertilizer. Although studies on the chemical and organic composition of vinasse and their impact on nitrous oxide emissions when applied in soil have been carried out, no studies have evaluated the microbial community composition and diversity in different forms of vinasse. We assessed the bacterial community composition of NCV and CV by non-culturable and culturable approaches. The non-culturable bacterial community was assessed by next generation sequencing of the 16S rRNA gene and culturable community by isolation of bacterial strains and molecular and biochemical characterization. Additionally, we assessed in the bacterial strains the presence of genes of nitrogen cycle nitrification and denitrification pathways. The microbial community based on 16S rRNA sequences of NCV was overrepresented by Bacilli and Negativicutes while CV was mainly represented by Bacilli class. The isolated strains from the two types of vinasse belong to class Bacilli, similar to Lysinibacillus, encode for nirK gene related to denitrification pathway. This study highlights the bacterial microbial composition particularly in CV what residue is currently recycled and recommended as a sustainable practice in sugarcane cultivation in the tropics.
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Affiliation(s)
| | - Afnan K A Suleiman
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands
| | | | | | - Eiko E Kuramae
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands
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70
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de Andrade Cavalcante D, De-Souza MT, de Orem JC, de Magalhães MIA, Martins PH, Boone TJ, Castillo JA, Driks A. Ultrastructural analysis of spores from diverse Bacillales species isolated from Brazilian soil. ENVIRONMENTAL MICROBIOLOGY REPORTS 2019; 11:155-164. [PMID: 30421850 DOI: 10.1111/1758-2229.12713] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 11/06/2018] [Indexed: 06/09/2023]
Abstract
Many species in the order Bacillales form a specialized cell type called a spore that is resistant to a range of environmental stresses. Transmission electron microscopy (TEM) reveals that the spore is comprised of a series of concentric shells, surrounding an interior compartment harbouring the spore DNA. The outermost of these shells varies considerably in morphology among species, likely reflecting adaptations to the highly diverse niches in which spores are found. To better characterize the variation in spore ultrastructure among diverse species, we used TEM to analyse spores from a collection of 23 aerobic spore-forming bacteria from the Solo do Distrito Federal (SDF strains), spanning the genera Bacillus, Lysinibacillus, Paenibacillus and Brevibacillus, isolated from soil from central Brazil. We found that the structures of these spores varied widely, as expected. Interestingly, even though these isolates are novel strains of each species, they were structurally very similar to the known examples of each species in the literature. Because in most cases, the species we analysed are poorly characterized, our data provide important evidence regarding which structural features are likely to be constant within a taxon and which are likely to vary.
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Affiliation(s)
| | | | | | | | | | - Tyler J Boone
- Stritch School of Medicine, Department of Microbiology and Immunology, Loyola University Chicago, IL, USA
| | - José A Castillo
- School of Biological Sciences and Engineering, Yachay Tech University, Urcuquí, Ecuador
| | - Adam Driks
- Stritch School of Medicine, Department of Microbiology and Immunology, Loyola University Chicago, IL, USA
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71
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Seligmann H. Giant viruses: spore‐like missing links betweenRickettsiaand mitochondria? Ann N Y Acad Sci 2019; 1447:69-79. [DOI: 10.1111/nyas.14022] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 01/10/2019] [Accepted: 01/16/2019] [Indexed: 12/27/2022]
Affiliation(s)
- Hervé Seligmann
- The National Natural History Collectionsthe Hebrew University of Jerusalem Jerusalem Israel
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72
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Tamayo-Figueroa DP, Castillo E, Brandão PFB. Metal and metalloid immobilization by microbiologically induced carbonates precipitation. World J Microbiol Biotechnol 2019; 35:58. [DOI: 10.1007/s11274-019-2626-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 03/04/2019] [Indexed: 12/12/2022]
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73
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Liu K, Liu Y, Han BP, Xu B, Zhu L, Ju J, Jiao N, Xiong J. Bacterial community changes in a glacial-fed Tibetan lake are correlated with glacial melting. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 651:2059-2067. [PMID: 30321727 DOI: 10.1016/j.scitotenv.2018.10.104] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 10/08/2018] [Accepted: 10/08/2018] [Indexed: 05/25/2023]
Abstract
Climate change-induced glacial melting is a global phenomenon. The effects of climate change-induced melting on the microbial ecology in different glacial-fed aquatic systems have been well illuminated, but the resolution of seasonal dynamics was still limited. Here, we studied bacterial community composition and diversity in a glacial-fed Tibetan lake, Lake Ranwu, to elucidate how glacial-fed aquatic ecosystems respond to the seasonal glacial melting. Obvious seasonal variations of bacterial dominant groups were found in Lake Ranwu and inlet rivers. In April, the majority of OTUs belonged to the Bacteroidetes, Actinobacteria and Proteobacteria. The Proteobacteria increased to the most abundant phylum in July and November, while the Bacteroidetes and Actinobacteria decreased about 50% over seasons. Most key discriminant taxa of each season's community strongly associated with specific environmental variables, suggesting their adaptation to seasonal environments. Bacterial alpha diversity varied among seasons and exhibited strongly negative correlations with conductivity. Conductivity was the major driving force in determining the seasonal variation of bacterial community composition. Fluctuated conductivity was one of the consequences of seasonal melting of glaciers. This study offered evidence for the unique seasonal dynamics pattern of bacterial communities responding to glacial melting. Moreover, this study may provide a reference for assessing the long-term effects of glacial retreat on glacial-fed aquatic ecosystems.
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Affiliation(s)
- Keshao Liu
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China
| | - Yongqin Liu
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101, China.
| | - Bo-Ping Han
- Institute of Hydrobiology, Jinan University, Guangzhou 510632, China
| | - Baiqing Xu
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101, China
| | - Liping Zhu
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101, China
| | - Jianting Ju
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China
| | - Nianzhi Jiao
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, PR China
| | - Jinbo Xiong
- School of Marine Sciences, Ningbo University, Ningbo 315211, China; Collaborative Innovation Center for Zhejiang Marine High-Efficiency and Healthy Aquaculture, Ningbo 315211, China
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Filippidou S, Junier T, Wunderlin T, Kooli WM, Palmieri I, Al-Dourobi A, Molina V, Lienhard R, Spangenberg JE, Johnson SL, Chain PSG, Dorador C, Junier P. Adaptive Strategies in a Poly-Extreme Environment: Differentiation of Vegetative Cells in Serratia ureilytica and Resistance to Extreme Conditions. Front Microbiol 2019; 10:102. [PMID: 30804904 PMCID: PMC6370625 DOI: 10.3389/fmicb.2019.00102] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 01/17/2019] [Indexed: 11/13/2022] Open
Abstract
Poly-extreme terrestrial habitats are often used as analogs to extra-terrestrial environments. Understanding the adaptive strategies allowing bacteria to thrive and survive under these conditions could help in our quest for extra-terrestrial planets suitable for life and understanding how life evolved in the harsh early earth conditions. A prime example of such a survival strategy is the modification of vegetative cells into resistant resting structures. These differentiated cells are often observed in response to harsh environmental conditions. The environmental strain (strain Lr5/4) belonging to Serratia ureilytica was isolated from a geothermal spring in Lirima, Atacama Desert, Chile. The Atacama Desert is the driest habitat on Earth and furthermore, due to its high altitude, it is exposed to an increased amount of UV radiation. The geothermal spring from which the strain was isolated is oligotrophic and the temperature of 54°C exceeds mesophilic conditions (15 to 45°C). Although the vegetative cells were tolerant to various environmental insults (desiccation, extreme pH, glycerol), a modified cell type was formed in response to nutrient deprivation, UV radiation and thermal shock. Scanning (SEM) and Transmission Electron Microscopy (TEM) analyses of vegetative cells and the modified cell structures were performed. In SEM, a change toward a circular shape with reduced size was observed. These circular cells possessed what appears as extra coating layers under TEM. The resistance of the modified cells was also investigated, they were resistant to wet heat, UV radiation and desiccation, while vegetative cells did not withstand any of those conditions. A phylogenomic analysis was undertaken to investigate the presence of known genes involved in dormancy in other bacterial clades. Genes related to spore-formation in Myxococcus and Firmicutes were found in S. ureilytica Lr5/4 genome; however, these genes were not enough for a full sporulation pathway that resembles either group. Although, the molecular pathway of cell differentiation in S. ureilytica Lr5/4 is not fully defined, the identified genes may contribute to the modified phenotype in the Serratia genus. Here, we show that a modified cell structure can occur as a response to extremity in a species that was previously not known to deploy this strategy. This strategy may be widely spread in bacteria, but only expressed under poly-extreme environmental conditions.
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Affiliation(s)
- Sevasti Filippidou
- Laboratory of Microbiology, University of Neuchatel, Neuchatel, Switzerland
- Microbial Ecology Group, Centre for Ecology and Hydrology, Wallingford, United Kingdom
- Space Microbiology Research Group, Radiation Biology Department, Institute of Aerospace Medicine, German Aerospace Center (DLR e.V.), Cologne, Germany
| | - Thomas Junier
- Vital-IT Group, Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Tina Wunderlin
- Laboratory of Microbiology, University of Neuchatel, Neuchatel, Switzerland
| | - Wafa M. Kooli
- Laboratory of Microbiology, University of Neuchatel, Neuchatel, Switzerland
| | - Ilona Palmieri
- Laboratory of Microbiology, University of Neuchatel, Neuchatel, Switzerland
| | - Andrej Al-Dourobi
- Laboratory of Microbiology, University of Neuchatel, Neuchatel, Switzerland
| | - Veronica Molina
- Departamento de Biología, Facultad de Ciencias Naturales y Exactas, Universidad de Playa Ancha, Valparaíso, Chile
| | | | - Jorge E. Spangenberg
- Institute of Earth Surface Dynamics, University of Lausanne, Lausanne, Switzerland
| | | | | | - Cristina Dorador
- Laboratorio de Complejidad Microbiana y Ecología Funcional, Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta, Chile
- Centre for Biotechnology and Bioengineering, Antofagasta, Chile
| | - Pilar Junier
- Laboratory of Microbiology, University of Neuchatel, Neuchatel, Switzerland
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Bacterial communities associated to Chilean altiplanic native plants from the Andean grasslands soils. Sci Rep 2019; 9:1042. [PMID: 30705356 PMCID: PMC6355873 DOI: 10.1038/s41598-018-37776-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 12/12/2018] [Indexed: 12/23/2022] Open
Abstract
The rhizosphere is considered the primary place for soil microbiome differentiation and plays a key role in plant survival, especially for those subjected to environmental stress. Using high-throughput sequencing of the 16S rRNA gene, we analyzed and compared soil bacterial communities associated to four of the most abundant high altitude native plant species of the Chilean Andean grasslands. We examined three soil compartments: the rhizosphere (bacteria firmly attached to the roots), the rhizosphere-surrounding soil (bacteria loosely attached to the roots) and the bulk soil (plant-free soil). The rhizosphere microbiome was in all cases the least diverse, exposing that the bulk soil was a more complex environment. Taxonomic analysis revealed an abrupt change between the rhizosphere and the rest of the non-rhizospheric soils. Thus, while rhizobacterial communities were enriched in Proteobacteria (mainly Alphaproteobacteria), Actinobacteria (mostly Blastocatellia) dominated in bulk soils. Finally, we detected certain taxonomic rhizosphere signatures, which could be attributed to a particular genotype. Overall, our results indicate that the thin layer of soil surrounding the roots constitute a distinctive soil environment. This study contributes to expand the knowledge about soil bacterial communities in the Chilean highlands and takes the first step to understand the processes that might lead to the rhizosphere differentiation in that area.
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76
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Schmitz AM, Pawlowska TE, Harrison MJ. A short LysM protein with high molecular diversity from an arbuscular mycorrhizal fungus, Rhizophagus irregularis. MYCOSCIENCE 2019. [DOI: 10.1016/j.myc.2018.09.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Tong J, Lu X, Zhang J, Angelidaki I, Wei Y. Factors influencing the fate of antibiotic resistance genes during thermochemical pretreatment and anaerobic digestion of pharmaceutical waste sludge. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 243:1403-1413. [PMID: 30278414 DOI: 10.1016/j.envpol.2018.09.096] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 09/17/2018] [Accepted: 09/19/2018] [Indexed: 05/16/2023]
Abstract
The prevalence of antibiotic resistance genes (ARGs) in waste sludge, especially for the pharmaceutical waste sludge, presents great potential risks to human health. Although ARGs and factors affecting their spreading are of major importance for human health, the factors influencing the fate of ARGs during sludge treatment, especially for pharmaceutical sludge treatment are not yet well understood. In order to be able to minimize ARGs spreading, it is important to find what is influencing their spreading. Therefore, certain factors, such as the sludge characteristics, bacterial diversity and community composition, and mobile genetic elements (MGEs) during the advanced AD of pharmaceutical sludge with different pretreatments were studied, and their affinity with ARGs was elucidated by Spearman correlation analysis. Furthermore, multiple linear regression was introduced to evaluate the importance of the various factors. Results showed that 59.7%-88.3% of the variations in individual ARGs and total ARGs can be explained by the corresponding factors. Bacterial diversity rather than specific bacterial community composition affected the fate of ARGs, whereas alkalinity was the most important factor on ARGs among all sludge characteristics investigated in this study. Besides, 66.4% of variation of total ARGs was driven by the changes of MGEs. Multiple linear regression models also reveal the collective effect of these factors on ARGs, and the contributions of each factor impact on ARGs. This study provides more comprehension about the factors impact on the fate of ARGs during pharmaceutical sludge treatment, and offers an approach to evaluate the importance of each factor, which method could be introduced for evaluation of factors influencing ARGs during other types of sludge or wastewater treatment.
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Affiliation(s)
- Juan Tong
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; Department of Water Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Xueting Lu
- Department of Water Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Junya Zhang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; Department of Water Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Irini Angelidaki
- Department of Environmental Engineering, Technical University of Denmark, Copenhagen Lyngby, 2800, Denmark
| | - Yuansong Wei
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; Department of Water Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
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78
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Lu C, Gu J, Wang X, Liu J, Zhang K, Zhang X, Zhang R. Effects of coal gasification slag on antibiotic resistance genes and the bacterial community during swine manure composting. BIORESOURCE TECHNOLOGY 2018; 268:20-27. [PMID: 30064034 DOI: 10.1016/j.biortech.2018.07.086] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Revised: 07/14/2018] [Accepted: 07/17/2018] [Indexed: 06/08/2023]
Abstract
This study investigated the effects of the addition of coal gasification slag (CGS) at three levels (0%, 5%, and 10% w/w) on antibiotic resistance genes (ARGs) and the bacterial community during composting. The addition of CGS effectively facilitated the removal of ARGs and mobile genetic elements (MGEs), where it significantly reduced the relative abundances of 5/11 ARGs and three MGEs in the swine manure composting product. In addition, the enrichment of ARGs and intI1 was lower under the addition of 10% CGS compared with 0% CGS. The bacterial community was distributed according to the composting time under different treatments. Redundancy analysis showed that bacterial community succession and MGE-mediated horizontal gene transfer played important roles in the variations in ARGs. Network analysis indicated the co-occurrence of ARGs and MGEs with specific microorganisms. Thus, 10% CGS may be a suitable additive for reducing the risks of ARGs in compost products.
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Affiliation(s)
- Chunya Lu
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Jie Gu
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China; Research Center of Recycle Agricultural Engineering and Technology of Shaanxi Province, Northwest A&F University, Yangling, Shaanxi 712100, China.
| | - Xiaojuan Wang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Jiayao Liu
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Kaiyu Zhang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Xin Zhang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Ranran Zhang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
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79
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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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80
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Bu F, Dong N, Kumar Khanal S, Xie L, Zhou Q. Effects of CO on hydrogenotrophic methanogenesis under thermophilic and extreme-thermophilic conditions: Microbial community and biomethanation pathways. BIORESOURCE TECHNOLOGY 2018; 266:364-373. [PMID: 29982059 DOI: 10.1016/j.biortech.2018.03.092] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/16/2018] [Accepted: 03/18/2018] [Indexed: 06/08/2023]
Abstract
Coke oven gas is considered as a potential hydrogen source for biogas bio-upgrading. In this study, the effects of CO on biomethanation performance and microbial community structure of hydrogenotrophic mixed cultures were investigated under thermophilic (55 °C) and extreme-thermophilic (70 °C) conditions. 5% (v/v) CO did not inhibit hydrogenotrophic methanogenesis during semi-continuous operation, and 83-97% CO conversion to CH4 was achieved. Methanothermobacter thermoautotrophicus was the dominant methanogen at both temperatures and was the main functional archaea associated with CO biomethanation. Specific methanogenic activity test results showed that long-term 5% CO acclimation shortened the lag phase from 5 h to 1 h at 55 °C and 15 h to 3 h at 70 °C. CO2 was the preferred carbon source over CO for hydrogenotrophic methanogens and CO consumption only started when CO2 was completely depleted. M. thermoautotrophicus dominated mixed cultures showed a great potential in simultaneous hydrogenotrophic methanogenesis and CO biomethanation.
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Affiliation(s)
- Fan Bu
- State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze River Water Environment, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, PR China
| | - Nanshi Dong
- State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze River Water Environment, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, PR China
| | - Samir Kumar Khanal
- Department of Molecular Biosciences and Bioengineering (MBBE), University of Hawai'i at Mānoa, 1955 East-West Road, Agricultural Science Building 218, Honolulu, HI 96822, USA
| | - Li Xie
- State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze River Water Environment, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, PR China.
| | - Qi Zhou
- State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze River Water Environment, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, PR China
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81
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Davidson P, Eutsey R, Redler B, Hiller NL, Laub MT, Durand D. Flexibility and constraint: Evolutionary remodeling of the sporulation initiation pathway in Firmicutes. PLoS Genet 2018; 14:e1007470. [PMID: 30212463 PMCID: PMC6136694 DOI: 10.1371/journal.pgen.1007470] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Accepted: 06/04/2018] [Indexed: 12/16/2022] Open
Abstract
The evolution of signal transduction pathways is constrained by the requirements of signal fidelity, yet flexibility is necessary to allow pathway remodeling in response to environmental challenges. A detailed understanding of how flexibility and constraint shape bacterial two component signaling systems is emerging, but how new signal transduction architectures arise remains unclear. Here, we investigate pathway remodeling using the Firmicute sporulation initiation (Spo0) pathway as a model. The present-day Spo0 pathways in Bacilli and Clostridia share common ancestry, but possess different architectures. In Clostridium acetobutylicum, sensor kinases directly phosphorylate Spo0A, the master regulator of sporulation. In Bacillus subtilis, Spo0A is activated via a four-protein phosphorelay. The current view favors an ancestral direct phosphorylation architecture, with the phosphorelay emerging in the Bacillar lineage. Our results reject this hypothesis. Our analysis of 84 broadly distributed Firmicute genomes predicts phosphorelays in numerous Clostridia, contrary to the expectation that the Spo0 phosphorelay is unique to Bacilli. Our experimental verification of a functional Spo0 phosphorelay encoded by Desulfotomaculum acetoxidans (Class Clostridia) further supports functional phosphorelays in Clostridia, which strongly suggests that the ancestral Spo0 pathway was a phosphorelay. Cross complementation assays between Bacillar and Clostridial phosphorelays demonstrate conservation of interaction specificity since their divergence over 2.7 BYA. Further, the distribution of direct phosphorylation Spo0 pathways is patchy, suggesting multiple, independent instances of remodeling from phosphorelay to direct phosphorylation. We provide evidence that these transitions are likely the result of changes in sporulation kinase specificity or acquisition of a sensor kinase with specificity for Spo0A, which is remarkably conserved in both architectures. We conclude that flexible encoding of interaction specificity, a phenotype that is only intermittently essential, and the recruitment of kinases to recognize novel environmental signals resulted in a consistent and repeated pattern of remodeling of the Spo0 pathway. Survival in a changing world requires signal transduction circuitry that can evolve to sense and respond to new environmental challenges. The Firmicute sporulation initiation (Spo0) pathway is a compelling example of a pathway with a circuit diagram that has changed over the course of evolution. In Clostridium acetobutylicum, a sensor kinase directly activates the master regulator of sporulation, Spo0A. In Bacillus subtilis, Spo0A is activated indirectly via a four-protein phosphorelay. These early observations suggested that the ancestral Spo0A was directly phosphorylated by a kinase in the earliest spore-former and that the Spo0 phosphorelay arose later in Bacilli via gain of additional proteins and interactions. Our analysis, based on a much larger set of genomes, surprisingly reveals phosphorelays, not only in Bacilli, but in many Clostridia. These findings support a model wherein sporulation was initiated by a Spo0 phosphorelay in the ancestral spore-former and the direct phosphorylation Spo0 pathways, which are observed in distinct sets of Clostridial taxa, are the result of convergent, reductive evolution. Further, our evidence suggests that these remodeling events were mediated by changes in kinase specificity, implicating flexible pathway remodeling, potentially combined with the recruitment of kinases, in Spo0 pathway evolution.
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Affiliation(s)
- Philip Davidson
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Rory Eutsey
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Brendan Redler
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - N. Luisa Hiller
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
- Center of Excellence in Biofilm Research, Allegheny Health Network, Pittsburgh, Pennsylvania, United States of America
| | - Michael T. Laub
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Dannie Durand
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
- Department of Computer Science, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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82
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Seal BS, Drider D, Oakley BB, Brüssow H, Bikard D, Rich JO, Miller S, Devillard E, Kwan J, Bertin G, Reeves S, Swift SM, Raicek M, Gay CG. Microbial-derived products as potential new antimicrobials. Vet Res 2018; 49:66. [PMID: 30060765 PMCID: PMC6066938 DOI: 10.1186/s13567-018-0563-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 02/01/2018] [Indexed: 12/24/2022] Open
Abstract
Due to the continuing global concerns involving antibiotic resistance, there is a need for scientific forums to assess advancements in the development of antimicrobials and their alternatives that might reduce development and spread of antibiotic resistance among bacterial pathogens. The objectives of the 2nd International Symposium on Alternatives to Antibiotics were to highlight promising research results and novel technologies that can provide alternatives to antibiotics for use in animal health and production, assess challenges associated with their authorization and commercialization for use, and provide actionable strategies to support their development. The session on microbial-derived products was directed at presenting novel technologies that included exploiting CRISPR-Cas nucleases to produce sequence-specific antimicrobials, probiotics development via fecal microbiome transplants among monogastric production animals such as chickens and mining microbial sources such as bacteria or yeast to identify new antimicrobial compounds. Other research has included continuing development of antimicrobial peptides such as newly discovered bacteriocins as alternatives to antibiotics, use of bacteriophages accompanied by development of unique lytic proteins with specific cell-wall binding domains and novel approaches such as microbial-ecology guided discovery of anti-biofilm compounds discovered in marine environments. The symposium was held at the Headquarters of the World Organisation for Animal Health (OIE) in Paris, France during 12-15 December 2016.
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Affiliation(s)
- Bruce S. Seal
- Biology Program, Oregon State University Cascades, 1500 SW Chandler Avenue, Bend, OR 97702 USA
| | - Djamel Drider
- Institut Charles Viollette, Université Lille 1, 59000 Lille, France
| | - Brian B. Oakley
- College of Veterinary Medicine, Western University of Health Sciences, 309 E Second St, Pomona, CA 91766-1854 USA
| | - Harald Brüssow
- Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, 1000 Lausanne 26, Switzerland
| | - David Bikard
- Synthetic Biology Group, Microbiology Department, Institut Pasteur, 75015 Paris, France
| | - Joseph O. Rich
- Renewable Product Technology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, U.S. Department of Agriculture, 1815 North University Street, Peoria, IL 61604 USA
| | - Stefan Miller
- Lisando GmbH, Josef-Engert-Straße 13, 93053 Regensburg, Germany
| | - Estelle Devillard
- Nutrition Research Team, Adisseo France S.A.S.-CERN, 6 Route Noire, 03600 Commentry, France
| | - Jason Kwan
- School of Pharmacy, University of Wisconsin, 777 Highland Ave., Madison, WI 53705-2222 USA
| | - Gérard Bertin
- European Probiotic Association & Erawan Consulting SARL, Asnières Affaires, 25 rue des Bas, 92600 Asnières-sur-Seine, France
| | - Stuart Reeves
- Embria Health Sciences, 2105 SE Creekview Dr., Ankeny, IA 50021 USA
| | - Steven M. Swift
- Animal Biosciences and Biotechnology Laboratory, BARC, Agricultural Research Service, USDA, 10300 Baltimore Ave, Beltsville, MD 20705-2350 USA
| | - Margot Raicek
- Intern, World Organisation for Animal Health (OIE), 12 rue de Prony, 75017 Paris, France
| | - Cyril G. Gay
- National Program Staff-Animal Health, Agricultural Research Service, US Department of Agriculture, Beltsville, MD 20705 USA
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83
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Giant viruses as protein-coated amoeban mitochondria? Virus Res 2018; 253:77-86. [DOI: 10.1016/j.virusres.2018.06.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 06/13/2018] [Accepted: 06/14/2018] [Indexed: 01/18/2023]
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84
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Corbett MK, Eksteen JJ, Niu XZ, Watkin ELJ. Syntrophic effect of indigenous and inoculated microorganisms in the leaching of rare earth elements from Western Australian monazite. Res Microbiol 2018; 169:558-568. [PMID: 29852218 DOI: 10.1016/j.resmic.2018.05.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 05/16/2018] [Accepted: 05/19/2018] [Indexed: 10/14/2022]
Abstract
The unique physiochemical properties exhibited by rare earth elements (REEs) and their increasing application in high-tech industries has created a demand for secure supply lines with established recovery procedures that create minimal environmental damage. Bioleaching experiments conducted on a non-sterile monazite concentrate with a known phosphate solubilising microorganism (PSM) resulted in greater mobilisation of REEs into solution in comparison to experiments conducted on sterile monazite. By combining the native consortia with an introduced PSM, a syntrophic effect between the populations effectively leached a greater amount of REEs than either a single PSM or the indigenous population alone. With sterile monazite, Penicillium sp.CF1 inoculated experiments released a total REE concentration of 12.32 mg L-1 after incubation for 8 days, whereas on non-sterile ore, double the soluble REE concentration was recorded (23.7 mg L-1). Comparable effects were recorded with Enterobacter aerogenes, Pantoea agglomerans and Pseudomonas putida. Alterations in the microbial populations during bioleaching of the monazite ore were determined by diversity profiling and demonstrated noticeable changes in community inhabitants over 14 days. The presence of native Firmicutes on the monazite appears to greatly contribute to the increased leaching recorded when using non-sterile monazite for REE recovery.
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Affiliation(s)
- Melissa K Corbett
- School of Pharmacy and Biomedical Sciences, CHIRI Biosciences, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.
| | - Jacques J Eksteen
- Western Australian School of Mines, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.
| | - Xi-Zhi Niu
- Curtin Water Quality Research Centre, Department of Chemistry, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.
| | - Elizabeth L J Watkin
- School of Pharmacy and Biomedical Sciences, CHIRI Biosciences, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.
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85
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Sylte MJ, Chandra LC, Looft T. Evaluation of disinfectants and antiseptics to eliminate bacteria from the surface of turkey eggs and hatch gnotobiotic poults. Poult Sci 2018; 96:2412-2420. [PMID: 28204763 DOI: 10.3382/ps/pex022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 01/09/2017] [Indexed: 01/27/2023] Open
Abstract
Bird eggs are in contact with intestinal microbiota at or after oviposition, but are protected from bacterial translocation by a glycoprotein cuticle layer, the shell, and internal membranes. In a preliminary study, turkey eggs were hatched in a germ-free environment. Firmicutes 16S rRNA gene was detected in the cecal microbiota of hatched poults, suggesting that poults may acquire spore-formers by exposure to shell contents during hatching. Generating gnotobiotic poults for research requires elimination of bacteria from the egg's surface without damaging the developing embryo. The ability of different disinfectants and antiseptics to eliminate eggshell bacteria without harming the developing embryo was tested. Different classes of disinfectants and antiseptics (halogens, biguanidines, and oxidants) were selected to target spores and vegetative bacteria likely present on the egg's surface. Eggs were treated by fully immersing in heated antiseptic (betadine or chlorhexidine) or disinfectant (alkaline bleach, acidified bleach, chlorine dioxide, Oxysept-333, or Virkon S) solutions for up to 15 minutes. Shells were aseptically harvested for aerobic and anaerobic culturing of bacteria. Toxicity to the developing embryo was assessed by gross evaluation of developmental changes in treated eggs incubated up to 27 d of embryonation. Halogen disinfectants acidified bleach and chlorine dioxide, and oxidants Oxysept-333 and Virkon-S eliminated viable bacteria from eggshells. However, addition of oxidants, alone or in combination with other treatments, produced significant (P < 0.05) embryotoxicity. The combination treatment of acidified bleach, chlorine dioxide, and betadine produced minimal embryotoxicity and eliminated viable bacteria from whole turkey eggs, and produced hatched poults in a gnotobiotic isolator. As a control, eggs were treated with PBS, incubated, and hatched under germ-replete conditions. After hatching, poults were euthanized and treated poults had no detectable bacterial growth or 16S rRNA gene qPCR amplification, demonstrating that acidified sodium hypochlorite, chlorine dioxide, and betadine safely hatched gnotobiotic poults. Generation of germ-free poults is an important tool and will be used to evaluate the host-pathogen interaction by foodborne pathogens such as Campylobacter spp.
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Affiliation(s)
- M J Sylte
- Food Safety and Enteric Pathogens Research Unit, U.S. Department of Agriculture, Agricultural Research Services, National Animal Disease Center, 1920 Dayton Avenue, Ames, IA 50010
| | - L C Chandra
- Food Safety and Enteric Pathogens Research Unit, U.S. Department of Agriculture, Agricultural Research Services, National Animal Disease Center, 1920 Dayton Avenue, Ames, IA 50010
| | - T Looft
- Food Safety and Enteric Pathogens Research Unit, U.S. Department of Agriculture, Agricultural Research Services, National Animal Disease Center, 1920 Dayton Avenue, Ames, IA 50010
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86
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Crossland WL, Tedeschi LO, Callaway TR, Miller MD, Smith WB, Cravey M. Effects of rotating antibiotic and ionophore feed additives on volatile fatty acid production, potential for methane production, and microbial populations of steers consuming a moderate-forage diet. J Anim Sci 2018; 95:4554-4567. [PMID: 29108045 DOI: 10.2527/jas2017.1665] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Ionophores and antibiotics have been shown to decrease ruminal methanogenesis both in vitro and in vivo but have shown little evidence toward a sustainable means of mitigation. Feed additive rotation was proposed and investigated for methane, VFA, and microbial population response. In the present study, cannulated steers ( = 12) were fed a moderate-forage basal diet in a Calan gate facility for 13 wk. In addition to the basal diet, steers were randomly assigned to 1 of 6 treatments: 1) control, no additive; 2) bambermycin, 20 mg bambermycin/d; 3) monensin, 200 mg monensin/d; 4) the basal diet + weekly rotation of bambermycin and monensin treatments (B7M); 5) the basal diet + rotation of bambermycin and monensin treatments every 14 d (B14M); and 6) the basal diet + rotation of bambermycin and monensin treatments every 21 d (B21M). Steers were blocked by weight in a randomized complete block design where the week was the repeated measure. Rumen fluid was collected weekly for analysis ( = 13), and results were normalized according to individual OM intake (OMI; kg/d). Potential activity of methane production was not significantly different among treatments ( > 0.05). However, treatment tended to affect the CH-to-propionate ratio ( = 0.0565), which was highest in the control and lowest in the monensin, B21M, and B14M treatments (0.42 vs. 0.36, 0.36, and 0.33, respectively). The CH:propionate ratio was lowest in wk 2 and 3 ( < 0.05) but the ratio in wk 4 to 12 was not different from the ratio in wk 0. Week also affected total VFA, with total VFA peaking at wk 3 and plummeting at wk 4 (4.02 vs. 2.86 m/kg OMI; < 0.05). A significant treatment × week interaction was observed for the acetate-to-propionate (A:P) ratio, where bambermycin- and rotationally fed steers did not have a reduced A:P ratio compared with monensin-fed steers throughout the feeding period ( < 0.0001). Microbial analysis revealed significant shifts, but several predominant classes showed adaptation between 4 and 6 wk after additive initiation. There was no significant evidence to suggest that rotations of monensin and bambermycin provided additional benefits to steers consuming a moderate-forage diet at the microbial/animal and environmental level versus those continuously fed.
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87
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Bacterial community structure associated with the rhizosphere soils and roots of Stellera chamaejasme L. along a Tibetan elevation gradient. ANN MICROBIOL 2018. [DOI: 10.1007/s13213-018-1336-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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88
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Espenberg M, Truu M, Mander Ü, Kasak K, Nõlvak H, Ligi T, Oopkaup K, Maddison M, Truu J. Differences in microbial community structure and nitrogen cycling in natural and drained tropical peatland soils. Sci Rep 2018; 8:4742. [PMID: 29549345 PMCID: PMC5856767 DOI: 10.1038/s41598-018-23032-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 03/06/2018] [Indexed: 01/02/2023] Open
Abstract
Tropical peatlands, which play a crucial role in the maintenance of different ecosystem services, are increasingly drained for agriculture, forestry, peat extraction and human settlement purposes. The present study investigated the differences between natural and drained sites of a tropical peatland in the community structure of soil bacteria and archaea and their potential to perform nitrogen transformation processes. The results indicate significant dissimilarities in the structure of soil bacterial and archaeal communities as well as nirK, nirS, nosZ, nifH and archaeal amoA gene-possessing microbial communities. The reduced denitrification and N2-fixing potential was detected in the drained tropical peatland soil. In undisturbed peatland soil, the N2O emission was primarily related to nirS-type denitrifiers and dissimilatory nitrate reduction to ammonium, while the conversion of N2O to N2 was controlled by microbes possessing nosZ clade I genes. The denitrifying microbial community of the drained site differed significantly from the natural site community. The main reducers of N2O were microbes harbouring nosZ clade II genes in the drained site. Additionally, the importance of DNRA process as one of the controlling mechanisms of N2O fluxes in the natural peatlands of the tropics revealed from the results of the study.
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Affiliation(s)
- Mikk Espenberg
- Department of Geography, Institute of Ecology and Earth Sciences, University of Tartu, 46 Vanemuise Street, 51014, Tartu, Estonia.
| | - Marika Truu
- Department of Geography, Institute of Ecology and Earth Sciences, University of Tartu, 46 Vanemuise Street, 51014, Tartu, Estonia
| | - Ülo Mander
- Department of Geography, Institute of Ecology and Earth Sciences, University of Tartu, 46 Vanemuise Street, 51014, Tartu, Estonia
| | - Kuno Kasak
- Department of Geography, Institute of Ecology and Earth Sciences, University of Tartu, 46 Vanemuise Street, 51014, Tartu, Estonia
| | - Hiie Nõlvak
- Department of Geography, Institute of Ecology and Earth Sciences, University of Tartu, 46 Vanemuise Street, 51014, Tartu, Estonia
| | - Teele Ligi
- Department of Geography, Institute of Ecology and Earth Sciences, University of Tartu, 46 Vanemuise Street, 51014, Tartu, Estonia
| | - Kristjan Oopkaup
- Department of Geography, Institute of Ecology and Earth Sciences, University of Tartu, 46 Vanemuise Street, 51014, Tartu, Estonia
| | - Martin Maddison
- Department of Geography, Institute of Ecology and Earth Sciences, University of Tartu, 46 Vanemuise Street, 51014, Tartu, Estonia
| | - Jaak Truu
- Department of Geography, Institute of Ecology and Earth Sciences, University of Tartu, 46 Vanemuise Street, 51014, Tartu, Estonia
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89
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Abstract
Bacterial endospores possess multiple integument layers, one of which is the cortex peptidoglycan wall. The cortex is essential for the maintenance of spore core dehydration and dormancy and contains structural modifications that differentiate it from vegetative cell peptidoglycan and determine its fate during spore germination. Following the engulfment stage of sporulation, the cortex is synthesized within the intermembrane space surrounding the forespore. Proteins responsible for cortex synthesis are produced in both the forespore and mother cell compartments. While some of these proteins also contribute to vegetative cell wall synthesis, others are sporulation specific. In order for the bacterial endospore to germinate and resume metabolism, the cortex peptidoglycan must first be degraded through the action of germination-specific lytic enzymes. These enzymes are present, yet inactive, in the dormant spore and recognize the muramic-δ-lactam modification present in the cortex. Germination-specific lytic enzymes across Bacillaceae and Clostridiaceae share this specificity determinant, which ensures that the spore cortex is hydrolyzed while the vegetative cell wall remains unharmed. Bacillus species tend to possess two redundant enzymes, SleB and CwlJ, capable of sufficient cortex degradation, while the clostridia have only one, SleC. Additional enzymes are often present that cannot initiate the cortex degradation process, but which can increase the rate of release of small fragments into the medium. Between the two families, the enzymes also differ in the enzymatic activities they possess and the mechanisms acting to restrict their activation until germination has been initiated.
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90
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Abstract
Despite being resistant to a variety of environmental insults, the bacterial endospore can sense the presence of small molecules and respond by germinating, losing the specialized structures of the dormant spore, and resuming active metabolism, before outgrowing into vegetative cells. Our current level of understanding of the spore germination process in bacilli and clostridia is reviewed, with particular emphasis on the germinant receptors characterized in Bacillus subtilis, Bacillus cereus, and Bacillus anthracis. The recent evidence for a local clustering of receptors in a "germinosome" would begin to explain how signals from different receptors could be integrated. The SpoVA proteins, involved in the uptake of Ca2+-dipicolinic acid into the forespore during sporulation, are also responsible for its release during germination. Lytic enzymes SleB and CwlJ, found in bacilli and some clostridia, hydrolyze the spore cortex: other clostridia use SleC for this purpose. With genome sequencing has come the appreciation that there is considerable diversity in the setting for the germination machinery between bacilli and clostridia.
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91
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Zhong XZ, Ma SC, Wang SP, Wang TT, Sun ZY, Tang YQ, Deng Y, Kida K. A comparative study of composting the solid fraction of dairy manure with or without bulking material: Performance and microbial community dynamics. BIORESOURCE TECHNOLOGY 2018; 247:443-452. [PMID: 28965075 DOI: 10.1016/j.biortech.2017.09.116] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 09/10/2017] [Accepted: 09/15/2017] [Indexed: 06/07/2023]
Abstract
The present study compared the development of various physicochemical properties and the composition of microbial communities involved in the composting process in the solid fraction of dairy manure (SFDM) with a sawdust-regulated SFDM (RDM). The changes in several primary physicochemical properties were similar in the two composting processes, and both resulted in mature end-products within 48days. The bacterial communities in both composting processes primarily comprised Proteobacteria and Bacteroidetes. Firmicutes were predominant in the thermophilic phase, whereas Chloroflexi, Planctomycetes, and Nitrospirae were more abundant in the final mature phase. Furthermore, the succession of bacteria in both groups proceeded in a similar pattern, suggesting that the effects of the bulking material on bacterial dynamics were minor. These results demonstrate the feasibility of composting using only the SFDM, reflected by the evolution of physicochemical properties and the microbial communities involved in the composting process.
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Affiliation(s)
- Xiao-Zhong Zhong
- College of Architecture and Environment, Sichuan University, No. 24 South Section 1, First Ring Road, Chengdu 610065, China
| | - Shi-Chun Ma
- Biogas Institute of Ministry of Agriculture, Ministry of Agriculture, No. 13 Section 4, Renmin Road South, Chengdu 610041, China; Key Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture, No. 13 Section 4, Renmin Road South, Chengdu 610041, China
| | - Shi-Peng Wang
- College of Architecture and Environment, Sichuan University, No. 24 South Section 1, First Ring Road, Chengdu 610065, China
| | - Ting-Ting Wang
- College of Architecture and Environment, Sichuan University, No. 24 South Section 1, First Ring Road, Chengdu 610065, China
| | - Zhao-Yong Sun
- College of Architecture and Environment, Sichuan University, No. 24 South Section 1, First Ring Road, Chengdu 610065, China.
| | - Yue-Qin Tang
- College of Architecture and Environment, Sichuan University, No. 24 South Section 1, First Ring Road, Chengdu 610065, China
| | - Yu Deng
- Biogas Institute of Ministry of Agriculture, Ministry of Agriculture, No. 13 Section 4, Renmin Road South, Chengdu 610041, China; Key Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture, No. 13 Section 4, Renmin Road South, Chengdu 610041, China
| | - Kenji Kida
- College of Architecture and Environment, Sichuan University, No. 24 South Section 1, First Ring Road, Chengdu 610065, China
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92
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Paliaga P, Korlević M, Ivančić I, Najdek M. Limited influence of primary treated sewage waters on bacterial abundance, production and community composition in coastal seawaters. MARINE ENVIRONMENTAL RESEARCH 2017; 131:215-226. [PMID: 29032852 DOI: 10.1016/j.marenvres.2017.09.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 09/12/2017] [Accepted: 09/14/2017] [Indexed: 06/07/2023]
Abstract
The response of bacteria in terms of abundance, production and community structure to changes induced by the discharge of primary treated sewage waters was investigated combining microbiological, chemical and molecular tools. The primary treatment did not affect substantially the bacterial community structure in wastewaters and did not reduce the concentrations of fecal indicators. The spatial distribution of the sewage plume was governed by vertical stratification and currents. Bacterial abundance and production in the sea receiving waste waters depended predominantly on environmental conditions. In the waters with the highest concentration of fecal pollution indicators the bacterial community was characterized by allochthonous bacteria belonging to Epsilonproteobacteria, Firmicutes, Gammaproteobacteria and Bacteroidetes. The latter two taxa were also present in unpolluted waters but had a different structure, typical for oligotrophic environments. Although the impact of primary treated sewage waters was limited, a sanitary risk persisted due to the relevant presence of potentially pathogenic bacteria.
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Affiliation(s)
- Paolo Paliaga
- Center for Marine Research, Ruđer Bošković Institute, G. Paliaga 5, 52210 Rovinj, Croatia.
| | - Marino Korlević
- Center for Marine Research, Ruđer Bošković Institute, G. Paliaga 5, 52210 Rovinj, Croatia.
| | - Ingrid Ivančić
- Center for Marine Research, Ruđer Bošković Institute, G. Paliaga 5, 52210 Rovinj, Croatia.
| | - Mirjana Najdek
- Center for Marine Research, Ruđer Bošković Institute, G. Paliaga 5, 52210 Rovinj, Croatia.
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93
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Jurburg SD, Nunes I, Brejnrod A, Jacquiod S, Priemé A, Sørensen SJ, Van Elsas JD, Salles JF. Legacy Effects on the Recovery of Soil Bacterial Communities from Extreme Temperature Perturbation. Front Microbiol 2017; 8:1832. [PMID: 28993764 PMCID: PMC5622210 DOI: 10.3389/fmicb.2017.01832] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 09/06/2017] [Indexed: 02/01/2023] Open
Abstract
The type and frequency of disturbances experienced by soil microbiomes is expected to increase given predicted global climate change scenarios and intensified anthropogenic pressures on ecosystems. While the direct effect of multiple disturbances to soil microbes has been explored in terms of function, their effect on the recovery of microbial community composition remains unclear. Here, we used soil microcosm experiments and multiple model disturbances to explore their short-term effect on the recovery of soil microbiota after identical or novel stresses. Soil microcosms were exposed to a heat shock to create an initial effect. Upon initial community recovery (25 days after stress), they were subjected to a second stress, either a heat or a cold shock, and they were monitored for additional 25 days. To carefully verify the bacterial response to the disturbances, we monitored changes in community composition throughout the experiment using 16S rRNA gene transcript amplicon sequencing. The application of a heat shock to soils with or without the initial heat shock resulted in similar successional dynamics, but these dynamics were faster in soils with a prior heat shock. The application of a cold shock had negligible effects on previously undisturbed soils but, in combination with an initial heat shock, caused the largest shift in the community composition. Our findings show that compounded perturbation affects bacterial community recovery by altering community structure and thus, the community's response during succession. By altering dominance patterns, disturbance legacy affects the microbiome's ability to recover from further perturbation within the 25 days studied. Our results highlight the need to consider the soil's disturbance history in the development of soil management practices in order to maintain the system's resilience.
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Affiliation(s)
- Stephanie D. Jurburg
- Microbial Ecology Group, Groningen Institute for Evolutionary Life Sciences, University of GroningenGroningen, Netherlands
- Bioinformatics group, Bioveterinary Institute, Wageningen University and ResearchWageningen, Netherlands
| | - Inês Nunes
- Section of Microbiology, University of CopenhagenCopenhagen, Denmark
- Microbe Technology Department, NovozymesCopenhagen, Denmark
| | - Asker Brejnrod
- Section of Microbiology, University of CopenhagenCopenhagen, Denmark
| | - Samuel Jacquiod
- Section of Microbiology, University of CopenhagenCopenhagen, Denmark
| | - Anders Priemé
- Section of Microbiology, University of CopenhagenCopenhagen, Denmark
| | - Søren J. Sørensen
- Section of Microbiology, University of CopenhagenCopenhagen, Denmark
| | - Jan Dirk Van Elsas
- Microbial Ecology Group, Groningen Institute for Evolutionary Life Sciences, University of GroningenGroningen, Netherlands
| | - Joana F. Salles
- Microbial Ecology Group, Groningen Institute for Evolutionary Life Sciences, University of GroningenGroningen, Netherlands
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94
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Abstract
Spores of Clostridiales and Bacillales are encased in a complex series of concentric shells that provide protection, facilitate germination, and mediate interactions with the environment. Analysis of diverse spore-forming species by thin-section transmission electron microscopy reveals that the number and morphology of these encasing shells vary greatly. In some species, they appear to be composed of a small number of discrete layers. In other species, they can comprise multiple, morphologically complex layers. In addition, spore surfaces can possess elaborate appendages. For all their variability, there is a consistent architecture to the layers encasing the spore. A hallmark of all Clostridiales and Bacillales spores is the cortex, a layer made of peptidoglycan. In close association with the cortex, all species examined possess, at a minimum, a series of proteinaceous layers, called the coat. In some species, including Bacillus subtilis, only the coat is present. In other species, including Bacillus anthracis, an additional layer, called the exosporium, surrounds the coat. Our goals here are to review the present understanding of the structure, composition, assembly, and functions of the coat, primarily in the model organism B. subtilis, but also in the small but growing number of other spore-forming species where new data are showing that there is much to be learned beyond the relatively well-developed basis of knowledge in B. subtilis. To help summarize this large field and define future directions for research, we will focus on key findings in recent years.
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95
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Abstract
Unrelated spore-forming bacteria share unique characteristics stemming from the presence of highly resistant endospores, leading to similar challenges in health and disease. These characteristics are related to the presence of these highly transmissible spores, which are commonly spread within the environment and are implicated in host-to-host transmission. In humans, spore-forming bacteria contribute to a variety of pathological processes that share similar characteristics, including persistence, chronicity, relapses and the maintenance of the resistome. We first outline the necessity of characterizing the totality of the spore-forming bacteria as the sporobiota based on their unique common characteristics. We further propose that the collection of all genes of spore-forming bacteria be known as the sporobiome. Such differentiation is critical for exploring the cross-talk between the sporobiota and other members of the gut microbiota, and will allow for a better understanding of the implications of the sporobiota and sporobiome in a variety of pathologies and the spread of antibiotic resistance.
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Affiliation(s)
- George Tetz
- Human Microbiology Institute, 423 West 127 Street, New York, NY 10027 USA
| | - Victor Tetz
- Human Microbiology Institute, 423 West 127 Street, New York, NY 10027 USA
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96
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Cuthbertson L, Amores-Arrocha H, Malard LA, Els N, Sattler B, Pearce DA. Characterisation of Arctic Bacterial Communities in the Air above Svalbard. BIOLOGY 2017; 6:biology6020029. [PMID: 28481257 PMCID: PMC5485476 DOI: 10.3390/biology6020029] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 04/20/2017] [Accepted: 04/21/2017] [Indexed: 01/09/2023]
Abstract
Atmospheric dispersal of bacteria is increasingly acknowledged as an important factor influencing bacterial community biodiversity, biogeography and bacteria–human interactions, including those linked to human health. However, knowledge about patterns in microbial aerobiology is still relatively scarce, and this can be attributed, in part, to a lack of consensus on appropriate sampling and analytical methodology. In this study, three different methods were used to investigate aerial biodiversity over Svalbard: impaction, membrane filtration and drop plates. Sites around Svalbard were selected due to their relatively remote location, low human population, geographical location with respect to air movement and the tradition and history of scientific investigation on the archipelago, ensuring the presence of existing research infrastructure. The aerial bacterial biodiversity found was similar to that described in other aerobiological studies from both polar and non-polar environments, with Proteobacteria, Actinobacteria, and Firmicutes being the predominant groups. Twelve different phyla were detected in the air collected above Svalbard, although the diversity was considerably lower than in urban environments elsewhere. However, only 58 of 196 bacterial genera detected were consistently present, suggesting potentially higher levels of heterogeneity. Viable bacteria were present at all sampling locations, showing that living bacteria are ubiquitous in the air around Svalbard. Sampling location influenced the results obtained, as did sampling method. Specifically, impaction with a Sartorius MD8 produced a significantly higher number of viable colony forming units (CFUs) than drop plates alone.
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Affiliation(s)
- Lewis Cuthbertson
- Department of Applied Sciences, Faculty of Health and Life Sciences, University of Northumbria at Newcastle, Ellison Building, Newcastle-upon-Tyne NE1 8ST, UK.
| | - Herminia Amores-Arrocha
- Department of Applied Sciences, Faculty of Health and Life Sciences, University of Northumbria at Newcastle, Ellison Building, Newcastle-upon-Tyne NE1 8ST, UK.
| | - Lucie A Malard
- Department of Applied Sciences, Faculty of Health and Life Sciences, University of Northumbria at Newcastle, Ellison Building, Newcastle-upon-Tyne NE1 8ST, UK.
| | - Nora Els
- Institute of Ecology, Austrian Polar Research Institute, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria.
| | - Birgit Sattler
- Institute of Ecology, Austrian Polar Research Institute, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria.
| | - David A Pearce
- Department of Applied Sciences, Faculty of Health and Life Sciences, University of Northumbria at Newcastle, Ellison Building, Newcastle-upon-Tyne NE1 8ST, UK.
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97
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Jurburg SD, Nunes I, Stegen JC, Le Roux X, Priemé A, Sørensen SJ, Salles JF. Autogenic succession and deterministic recovery following disturbance in soil bacterial communities. Sci Rep 2017; 7:45691. [PMID: 28383027 PMCID: PMC5382530 DOI: 10.1038/srep45691] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 03/03/2017] [Indexed: 01/23/2023] Open
Abstract
The response of bacterial communities to environmental change may affect local to global nutrient cycles. However the dynamics of these communities following disturbance are poorly understood, given that they are often evaluated over macro-ecological time scales and end-point measurements. In order to understand the successional trajectory of soil bacterial communities following disturbances and the mechanisms controlling these dynamics at a scale relevant for these organisms, we subjected soil microcosms to a heat disturbance and followed the community composition of active bacteria over 50 days. The disturbance imposed a strong selective pressure that persisted for up to 10 days, after which the importance of stochastic processes increased. Three successional stages were detected: a primary response in which surviving taxa increased in abundance; a secondary response phase during which community dynamics slowed down, and a stability phase (after 29 days), during which the community tended towards its original composition. Phylogenetic turnover patterns indicated that the community experienced stronger deterministic selection during recovery. Thus, soil bacterial communities, despite their extreme diversity and functional redundancy, respond to disturbances like many macro-ecological systems and exhibit path-dependent, autogenic dynamics during secondary succession. These results highlight the role of autogenic factors and successional dynamics in microbial recovery.
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Affiliation(s)
- Stephanie D Jurburg
- Genomic Research in Ecology and Evolution in Nature (GREEN), Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Nijenborgh 7, Groningen, 9747 AG, The Netherlands
| | - Inês Nunes
- Section of Microbiology, University of Copenhagen, Universitetsparken 15, Building 1, 2100 Copenhagen, Denmark
| | - James C Stegen
- Earth and Biological Sciences, Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Xavier Le Roux
- Microbial Ecology Center, INRA (UMR 1418), CNRS, Université Lyon1, Université de Lyon, 69622 Villeurbanne, France
| | - Anders Priemé
- Section of Microbiology, University of Copenhagen, Universitetsparken 15, Building 1, 2100 Copenhagen, Denmark
| | - Søren J Sørensen
- Section of Microbiology, University of Copenhagen, Universitetsparken 15, Building 1, 2100 Copenhagen, Denmark
| | - Joana Falcão Salles
- Genomic Research in Ecology and Evolution in Nature (GREEN), Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Nijenborgh 7, Groningen, 9747 AG, The Netherlands
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98
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Tanner AW, Carabetta VJ, Martinie RJ, Mashruwala AA, Boyd JM, Krebs C, Dubnau D. The RicAFT (YmcA-YlbF-YaaT) complex carries two [4Fe-4S] 2+ clusters and may respond to redox changes. Mol Microbiol 2017; 104:837-850. [PMID: 28295778 DOI: 10.1111/mmi.13667] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/11/2017] [Indexed: 01/10/2023]
Abstract
During times of environmental insult, Bacillus subtilis undergoes developmental changes leading to biofilm formation, sporulation and competence. Each of these states is regulated in part by the phosphorylated form of the master response regulator Spo0A (Spo0A∼P). The phosphorylation state of Spo0A is controlled by a multi-component phosphorelay. RicA, RicF and RicT (previously YmcA, YlbF and YaaT) have been shown to be important regulatory proteins for multiple developmental fates. These proteins directly interact and form a stable complex, which has been proposed to accelerate the phosphorelay. Indeed, this complex is sufficient to stimulate the rate of phosphotransfer amongst the phosphorelay proteins in vitro. In this study, we demonstrate that two [4Fe-4S]2+ clusters can be assembled on the complex. As with other iron-sulfur cluster-binding proteins, the complex was also found to bind FAD, hinting that these cofactors may be involved in sensing the cellular redox state. This work provides the first comprehensive characterization of an iron-sulfur protein complex that regulates Spo0A∼P levels. Phylogenetic and genetic evidence suggests that the complex plays a broader role beyond stimulation of the phosphorelay.
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Affiliation(s)
- Andrew W Tanner
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA
| | - Valerie J Carabetta
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA.,Public Health Research Institute Center, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA
| | - Ryan J Martinie
- Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Ameya A Mashruwala
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, 08901, USA
| | - Jeffrey M Boyd
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, 08901, USA
| | - Carsten Krebs
- Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA.,Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - David Dubnau
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA.,Public Health Research Institute Center, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA
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99
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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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100
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Davey L, Halperin SA, Lee SF. Thiol-Disulfide Exchange in Gram-Positive Firmicutes. Trends Microbiol 2016; 24:902-915. [PMID: 27426970 DOI: 10.1016/j.tim.2016.06.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 06/08/2016] [Accepted: 06/28/2016] [Indexed: 11/17/2022]
Abstract
Extracytoplasmic thiol-disulfide oxidoreductases (TDORs) catalyze the oxidation, reduction, and isomerization of protein disulfide bonds. Although these processes have been characterized in Gram-negative bacteria, the majority of Gram-positive TDORs have only recently been discovered. Results from recent studies have revealed distinct trends in the types of TDOR used by different groups of Gram-positive bacteria, and in their biological functions. Actinobacteria TDORs can be essential for viability, while Firmicute TDORs influence various physiological processes, including protein stability, oxidative stress resistance, bacteriocin production, and virulence. In this review we discuss the diverse extracytoplasmic TDORs used by Gram-positive bacteria, with a focus on Gram-positive Firmicutes.
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Affiliation(s)
- Lauren Davey
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, B3H 1X5 Canada; Canadian Center for Vaccinology, Dalhousie University and the IWK Health Centre, Halifax, NS, B3K 6R8 Canada
| | - Scott A Halperin
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, B3H 1X5 Canada; Canadian Center for Vaccinology, Dalhousie University and the IWK Health Centre, Halifax, NS, B3K 6R8 Canada; Department of Pediatrics, Faculty of Medicine, Dalhousie University and the IWK Health Centre, Halifax, NS, B3K 6R8 Canada
| | - Song F Lee
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, B3H 1X5 Canada; Canadian Center for Vaccinology, Dalhousie University and the IWK Health Centre, Halifax, NS, B3K 6R8 Canada; Department of Pediatrics, Faculty of Medicine, Dalhousie University and the IWK Health Centre, Halifax, NS, B3K 6R8 Canada; Department of Applied Oral Sciences, Faculty of Dentistry, Dalhousie University, Halifax, NS, B3H 4R2 Canada.
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