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Gajbhiye S, Gonzales ED, Toso DB, Kirk NA, Hickey WJ. Identification of NpdA as the protein forming the surface layer in Paracidovorax citrulli and evidence of its occurrence as a surface layer protein in diverse genera of the Betaproteobacteria and Gammaproteobacteria. Access Microbiol 2023; 5:000685.v3. [PMID: 38188235 PMCID: PMC10765051 DOI: 10.1099/acmi.0.000685.v3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 11/13/2023] [Indexed: 01/09/2024] Open
Abstract
The phytopathogen Paracidovorax citrulli possesses an ortholog of a newly identified surface layer protein (SLP) termed NpdA but has not been reported to produce a surface layer (S-layer). This study had two objectives. First, to determine if P. citrulli formed an NpdA-based S-layer and, if so, assess the effects of S-layer formation on virulence, production of nanostructures termed nanopods, and other phenotypes. Second, to establish the distribution of npdA orthologs throughout the Pseudomonadota and examine selected candidate cultures for physical evidence of S-layer formation. Formation of an NpdA-based S-layer by P. citrulli AAC00-1 was confirmed by gene deletion mutagenesis (ΔnpdA), proteomics, and cryo-electron microscopy. There were no significant differences between the wild-type and mutant in virulence assays with detached watermelon fruit. Nanopods contiguous with S-layers of multiple biofilm cells were visualized by transmission electron microscopy. Orthologs of npdA were identified in 62 Betaproteobacteria species and 49 Gammaproteobacteria species. In phylogenetic analyses, NpdA orthologs largely segregated into distinct groups. Cryo-electron microscopy imaging revealed an NpdA-like S-layer in all but one of the 16 additional cultures examined. We conclude that NpdA represents a new family of SLP, forming an S-layer in P. citrulli and other Pseudomonadota. While the S-layer did not contribute to virulence in watermelon fruit, a potential role of the P. citrulli S-layer in another dimension of pathogenesis cannot be ruled out. Lastly, formation of cell-bridging nanopods in biofilms is a new property of S-layers; it remains to be determined if nanopods can mediate intercellular movement of materials.
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Affiliation(s)
- Shabda Gajbhiye
- Department of Bacteriology, University of Wisconsin, Madison, Wisconsin, USA
| | - Erin D Gonzales
- Department of Soil Science, University of Wisconsin, Madison, Wisconsin, USA
| | - Daniel B Toso
- Department of Soil Science, University of Wisconsin, Madison, Wisconsin, USA
- Present address: California Institute for Quantitative Biosciences, University of California, Berkeley, California, USA
| | - Natalie A Kirk
- Department of Soil Science, University of Wisconsin, Madison, Wisconsin, USA
- Present address: Department of Art and Art History, University of Utah, Salt Lake City, Utah, USA
| | - William J Hickey
- Department of Soil Science, University of Wisconsin, Madison, Wisconsin, USA
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Ahmed MMA, Tripathi SK, Boudreau PD. Comparative metabolomic profiling of Cupriavidus necator B-4383 revealed production of cupriachelin siderophores, one with activity against Cryptococcus neoformans. Front Chem 2023; 11:1256962. [PMID: 37693169 PMCID: PMC10484230 DOI: 10.3389/fchem.2023.1256962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 08/07/2023] [Indexed: 09/12/2023] Open
Abstract
Cupriavidus necator H16 is known to be a rich source of linear lipopeptide siderophores when grown under iron-depleted conditions; prior literature termed these compounds cupriachelins. These small molecules bear β-hydroxyaspartate moieties that contribute to a photoreduction of iron when bound as ferric cupriachelin. Here, we present structural assignment of cupriachelins from C. necator B-4383 grown under iron limitation. The characterization of B-4383 cupriachelins is based on MS/MS fragmentation analysis, which was confirmed by 1D- and 2D-NMR for the most abundant analog (1). The cupriachelin congeners distinguish these two strains with differences in the preferred lipid tail; however, our rigorous metabolomic investigation also revealed minor analogs with changes in the peptide core, hinting at a potential mechanism by which these siderophores may reduce biologically unavailable ferric iron (4-6). Antifungal screening of the C. necator B-4383 supernatant extract and the isolated cupriachelin analog (1) revealed inhibitory activity against Cryptococcus neoformans, with IC50 values of 16.6 and 3.2 μg/mL, respectively. This antifungal activity could be explained by the critical role of the iron acquisition pathway in the growth and pathogenesis of the C. neoformans fungal pathogen.
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Affiliation(s)
- Mohammed M. A. Ahmed
- Boudreau Lab, Department of BioMolecular Sciences, School of Pharmacy, University of Mississippi, Oxford, MS, United States
- Department of Pharmacognosy, Al-Azhar University, Cairo, Egypt
| | - Siddarth K. Tripathi
- National Center for Natural Products Research, School of Pharmacy, University of Mississippi, Oxford, MS, United States
| | - Paul D. Boudreau
- Boudreau Lab, Department of BioMolecular Sciences, School of Pharmacy, University of Mississippi, Oxford, MS, United States
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Du J, Liu Y, Zhu H. Genome-based analyses of the genus Acidovorax: proposal of the two novel genera Paracidovorax gen. nov., Paenacidovorax gen. nov. and the reclassification of Acidovorax antarcticus as Comamonas antarctica comb. nov. and emended description of the genus Acidovorax. Arch Microbiol 2022; 205:42. [PMID: 36574033 DOI: 10.1007/s00203-022-03379-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/12/2022] [Accepted: 12/15/2022] [Indexed: 12/28/2022]
Abstract
The genus Acidovorax is a genetically heterogeneous species clustering that comprises many environmental and plant-pathogenic taxa. To better understand the evolutionary relationships among the Acidovorax species, 22 available genome sequences of type strains including the genera Acidovorax and Comamonas were used to conduct the genome-based analyses. Three well-supported monophyletic clusters of the Acidovorax species were determined based on the phylogenomic tree reconstructed using core genes, while they were not grouped in the 16S rRNA gene-based phylogenetic tree. The species arrangements of the genus Acidovorax were further confirmed by the comparisons of the digital DNA-DNA hybridization and average nucleotide identity (ANI) values. The ANI, average amino acid identity, and the percentage of conserved proteins values among the inter-clusters were approximately 83, 81, and 61%, respectively, and thus were proposed as practical thresholds for genus delineation. Besides, Acidovorax antarcticus was much closer to members of the genus Comamonas rather than those of the genus Acidovorax based on the genome-based analysis. Taken together, we propose the division of the current genus Acidovorax into the emended genus Acidovorax and the two novel genera Paracidovorax gen. nov., Paenacidovorax gen. nov. and the transfer of Acidovorax antarcticus into the genus Comamonas as Comamonas antarctica comb. nov.
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Affiliation(s)
- Juan Du
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Building 66, Xianlie Middle Road 100, Guangzhou, 510070, Guangdong Province, People's Republic of China
| | - Yang Liu
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Building 66, Xianlie Middle Road 100, Guangzhou, 510070, Guangdong Province, People's Republic of China
| | - Honghui Zhu
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Building 66, Xianlie Middle Road 100, Guangzhou, 510070, Guangdong Province, People's Republic of China.
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Kanukollu S, Remus R, Rücker AM, Buchen-Tschiskale C, Hoffmann M, Kolb S. Methanol utilizers of the rhizosphere and phyllosphere of a common grass and forb host species. ENVIRONMENTAL MICROBIOME 2022; 17:35. [PMID: 35794633 PMCID: PMC9258066 DOI: 10.1186/s40793-022-00428-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 06/14/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Managed grasslands are global sources of atmospheric methanol, which is one of the most abundant volatile organic compounds in the atmosphere and promotes oxidative capacity for tropospheric and stratospheric ozone depletion. The phyllosphere is a favoured habitat of plant-colonizing methanol-utilizing bacteria. These bacteria also occur in the rhizosphere, but their relevance for methanol consumption and ecosystem fluxes is unclear. Methanol utilizers of the plant-associated microbiota are key for the mitigation of methanol emission through consumption. However, information about grassland plant microbiota members, their biodiversity and metabolic traits, and thus key actors in the global methanol budget is largely lacking. RESULTS We investigated the methanol utilization and consumption potentials of two common plant species (Festuca arundinacea and Taraxacum officinale) in a temperate grassland. The selected grassland exhibited methanol formation. The detection of 13C derived from 13C-methanol in 16S rRNA of the plant microbiota by stable isotope probing (SIP) revealed distinct methanol utilizer communities in the phyllosphere, roots and rhizosphere but not between plant host species. The phyllosphere was colonized by members of Gamma- and Betaproteobacteria. In the rhizosphere, 13C-labelled Bacteria were affiliated with Deltaproteobacteria, Gemmatimonadates, and Verrucomicrobiae. Less-abundant 13C-labelled Bacteria were affiliated with well-known methylotrophs of Alpha-, Gamma-, and Betaproteobacteria. Additional metagenome analyses of both plants were consistent with the SIP results and revealed Bacteria with methanol dehydrogenases (e.g., MxaF1 and XoxF1-5) of known but also unusual genera (i.e., Methylomirabilis, Methylooceanibacter, Gemmatimonas, Verminephrobacter). 14C-methanol tracing of alive plant material revealed divergent potential methanol consumption rates in both plant species but similarly high rates in the rhizosphere and phyllosphere. CONCLUSIONS Our study revealed the rhizosphere as an overlooked hotspot for methanol consumption in temperate grasslands. We further identified unusual new but potentially relevant methanol utilizers besides well-known methylotrophs in the phyllosphere and rhizosphere. We did not observe a plant host-specific methanol utilizer community. Our results suggest that our approach using quantitative SIP and metagenomics may be useful in future field studies to link gross methanol consumption rates with the rhizosphere and phyllosphere microbiome.
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Affiliation(s)
- Saranya Kanukollu
- Microbial Biogeochemistry, RA1 Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Rainer Remus
- Isotope Biogeochemistry and Gas Fluxes, RA1 Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | | | - Caroline Buchen-Tschiskale
- Isotope Biogeochemistry and Gas Fluxes, RA1 Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
- Present Address: Johann Heinrich von Thünen-Institut, Institute of Climate-Smart Agriculture, Braunschweig, Germany
| | - Mathias Hoffmann
- Isotope Biogeochemistry and Gas Fluxes, RA1 Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Steffen Kolb
- Microbial Biogeochemistry, RA1 Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
- Thaer Institute, Faculty of Life Sciences, Humboldt University of Berlin, Berlin, Germany
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Caira JN, Jensen K. Electron microscopy reveals novel external specialized organs housing bacteria in eagle ray tapeworms. PLoS One 2021; 16:e0244586. [PMID: 33481793 PMCID: PMC7822281 DOI: 10.1371/journal.pone.0244586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 12/11/2020] [Indexed: 12/03/2022] Open
Abstract
Nutritionally-based mutualisms with bacteria are known to occur in a wide array of invertebrate phyla, although less commonly in the Platyhelminthes. Here we report what appears to be a novel example of this type of association in two geographically disparate and phylogenetically distant species of tapeworms of eagle rays-the lecanicephalidean Elicilacunosus dharmadii off the island of Borneo and the tetraphyllidean Caulobothrium multispelaeum off Senegal. Scanning and transmission electron microscopy revealed that the grooves and apertures on the outer surfaces of both tapeworms open into expansive cavities housing concentrations of bacteria. This led us to reject the original hypothesis that these structures, and their associated mucopolysaccharides, aid in attachment to the host mucosa. The cavities were found to be specialized in-foldings of the tapeworm body that were lined with particularly elongate filitriches. Given tapeworms lack a gut and employ filitriches to assist in nutrient absorption, enhanced nutrient uptake likely occurs in the cavities. Each tapeworm species appeared to host different bacterial monocultures; those in E. dharmadii were coccoid-like in form, while those in C. multispelaeum were bacillus-like. The presence of bacteria in a specialized structure of this nature suggests the structure is a symbiotic organ. Tapeworms are fully capable of obtaining their own nutrients, and thus the bacteria likely serve merely to supplement their diet. Given the bacteria were also extracellular, this structure is more consistent with a mycetome than a trophosome. To our knowledge, this is not only the first evidence of an external symbiotic organ of any type in a nutritionally-based mutualism, but also the first description of a mycetome in a group of invertebrates that lacks a digestive system. The factors that might account for the independent evolution of this unique association in these unrelated tapeworms are unclear-especially given that none of their closest relatives exhibit any evidence of the phenomenon.
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Affiliation(s)
- Janine N. Caira
- Department of Ecology & Evolutionary Biology, University of Connecticut, Storrs, Connecticut, United States of America
| | - Kirsten Jensen
- Department of Ecology & Evolutionary Biology and the Biodiversity Institute, University of Kansas, Lawrence, Kansas, United States of America
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Zeibich L, Guhl J, Drake HL. Impact of water content and dietary organic carbon richness on gut bacteria in the earthworm Lumbricus terrestris. FEMS MICROBES 2020. [DOI: 10.1093/femsmc/xtaa002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
ABSTRACTMany higher and lower animal gut ecosystems have complex resident microbial communities. In contrast, ingested soil is the primary source of the gut microbial diversity of earthworms, invertebrates of fundamental importance to the terrestrial biosphere. Earthworms also harbor a few endemic bacteria including Tenericutes-affiliated Candidatus Lumbricincola of unknown function. Gut microbes are subject to nutrient fluctuations due to dilution effects during gut passage, the nutrient richness of the anoxic gut, and dietary organic carbon, factors that could alter their activity/detection. This study's objective was to assess the potential impact of these factors on the occurrence and activity of ingested and endemic bacteria in gut content of Lumbricus terrestris. Fermentation product profiles of anoxic undiluted and diluted gut content treatments were similar, suggesting that experimental increase in water content and nutrient dilution had marginal impact on fermentation. However, 16S ribosomal Ribonucleic Acid (16S rRNA) sequence abundances indicated that stimulated bacterial taxa were not identical in undiluted and diluted treatments, with dominate potentially functionally redundant phylotypes being affiliated to the Firmicutes, Fusobacteria and Proteobacteria. Although the earthworm-associated Tenericutes were not stimulated in these treatments, the occurrence of three Tenericutes-affiliated phylotypes varied with the organic carbon richness of the earthworm diet, with two phylotypes being associated with high organic carbon richness. 16S rRNA sequence abundances indicated that other dominant gut taxa also varied with dietary organic carbon richness. These findings illustrate that functionally redundant ingested bacteria and earthworm-associated Tenericutes might be influenced by nutrient fluctuations in the gut and organic carbon richness of the earthworm diet.
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Affiliation(s)
- Lydia Zeibich
- Department of Ecological Microbiology, University of Bayreuth, Dr.-Hans-Frisch Strasse 1-3, 95440 Bayreuth, Germany
| | - Jennifer Guhl
- Department of Ecological Microbiology, University of Bayreuth, Dr.-Hans-Frisch Strasse 1-3, 95440 Bayreuth, Germany
| | - Harold L Drake
- Department of Ecological Microbiology, University of Bayreuth, Dr.-Hans-Frisch Strasse 1-3, 95440 Bayreuth, Germany
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Arumugaperumal A, Paul S, Lathakumari S, Balasubramani R, Sivasubramaniam S. The draft genome of a new Verminephrobacter eiseniae strain: a nephridial symbiont of earthworms. ANN MICROBIOL 2020. [DOI: 10.1186/s13213-020-01549-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Abstract
Purpose
Verminephrobacter is a genus of symbiotic bacteria that live in the nephridia of earthworms. The bacteria are recruited during the embryonic stage of the worm and transferred from generation to generation in the same manner. The worm provides shelter and food for the bacteria. The bacteria deliver micronutrients to the worm. The present study reports the genome sequence assembly and annotation of a new strain of Verminephrobacter called Verminephrobacter eiseniae msu.
Methods
We separated the sequences of a new Verminephrobacter strain from the whole genome of Eisenia fetida using the sequence of V. eiseniae EF01-2, and the bacterial genome was assembled using the CLC Workbench. The de novo-assembled genome was annotated and analyzed for the protein domains, functions, and metabolic pathways. Besides, the multigenome comparison was performed to interpret the phylogenomic relationship of the strain with other proteobacteria.
Result
The FastqSifter sifted a total of 593,130 Verminephrobacter genomic reads. The de novo assembly of the reads generated 1832 contigs with a total genome size of 4.4 Mb. The Average Nucleotide Identity denoted the bacterium belongs to the species V. eiseniae, and the 16S rRNA analysis confirmed it as a new strain of V. eiseniae. The AUGUSTUS genome annotation predicted a total of 3809 protein-coding genes; of them, 3805 genes were identified from the homology search.
Conclusion
The bioinformatics analysis confirmed the bacterium is an isolate of V. eiseniae, and it was named Verminephrobacter eiseniae msu. The whole genome of the bacteria can be utilized as a useful resource to explore the area of symbiosis further.
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Antoine R, Rivera-Millot A, Roy G, Jacob-Dubuisson F. Relationships Between Copper-Related Proteomes and Lifestyles in β Proteobacteria. Front Microbiol 2019; 10:2217. [PMID: 31608037 PMCID: PMC6769254 DOI: 10.3389/fmicb.2019.02217] [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: 06/04/2019] [Accepted: 09/11/2019] [Indexed: 12/25/2022] Open
Abstract
Copper is an essential transition metal whose redox properties are used for a variety of enzymatic oxido-reductions and in electron transfer chains. It is also toxic to living beings, and therefore its cellular concentration must be strictly controlled. We have performed in silico analyses of the predicted proteomes of more than one hundred species of β proteobacteria to characterize their copper-related proteomes, including cuproproteins, i.e., proteins with active-site copper ions, copper chaperones, and copper-homeostasis systems. Copper-related proteomes represent between 0 and 1.48% of the total proteomes of β proteobacteria. The numbers of cuproproteins are globally proportional to the proteome sizes in all phylogenetic groups and strongly linked to aerobic respiration. In contrast, environmental bacteria have considerably larger proportions of copper-homeostasis systems than the other groups of bacteria, irrespective of their proteome sizes. Evolution toward commensalism, obligate, host-restricted pathogenesis or symbiosis is globally reflected in the loss of copper-homeostasis systems. In endosymbionts, defense systems and copper chaperones have disappeared, whereas residual cuproenzymes are electron transfer proteins for aerobic respiration. Lifestyle is thus a major determinant of the size and composition of the copper-related proteome, and it is particularly reflected in systems involved in copper homeostasis. Analyses of the copper-related proteomes of a number of species belonging to the Burkholderia, Bordetella, and Neisseria genera indicates that commensals are in the process of shedding their copper-homeostasis systems and chaperones to greater extents yet than pathogens.
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Affiliation(s)
| | | | | | - Françoise Jacob-Dubuisson
- Université de Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 8204 – Center for Infection and Immunity of Lille, Lille, France
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Gholami F, Mosmeri H, Shavandi M, Dastgheib SMM, Amoozegar MA. Application of encapsulated magnesium peroxide (MgO 2) nanoparticles in permeable reactive barrier (PRB) for naphthalene and toluene bioremediation from groundwater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 655:633-640. [PMID: 30476844 DOI: 10.1016/j.scitotenv.2018.11.253] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 11/16/2018] [Accepted: 11/17/2018] [Indexed: 06/09/2023]
Abstract
One of the challenges in the petroleum hydrocarbon contaminated groundwater remediation by oxygen releasing compounds (ORCs) is to identify the remediation mechanism and determine the impact of ORCs on the environment and the intrinsic groundwater microorganisms. In this research, the application of encapsulated magnesium peroxide (MgO2) nanoparticles in the permeable reactive barrier (PRB) for bioremediation of the groundwater contaminated by toluene and naphthalene was studied in the continuous flow sand-packed plexiglass columns within 50 d experiments. For the biodiversity studies, next generation sequencing (NGS) of the 16S rRNA gene was applied. The results showed that naphthalene was metabolized (within 20 days) faster than toluene (after 30 days) by microorganisms of the aqueous phase. By comparing the contaminant removal in the biotic (which resulted in the complete contaminant removal) and abiotic (around 32% removal for naphthalene and 36% for toluene after 50 d) conditions, the significant role of microorganisms on the decontamination process was proved. Furthermore, the attached microbial communities on the porous media were visualized by scanning electron microscopy (SEM). Microbial community structure analysis by NGS technique revealed that the microbial species which were able to degrade toluene and naphthalene such as P. putida and P. mendocina respectively were stimulated by addition of MgO2 nanoparticles. The presented study resulted in a momentous insight into the application of MgO2 nanoparticles in the hydrocarbon compounds removal from groundwater.
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Affiliation(s)
- Fatemeh Gholami
- Department of Microbiology, College of Science, University of Tehran, Tehran, Iran
| | - Hamid Mosmeri
- Ecology and Environmental Pollution Control Research Group, Research Institute of Petroleum Industry, Tehran, Iran
| | - Mahmoud Shavandi
- Ecology and Environmental Pollution Control Research Group, Research Institute of Petroleum Industry, Tehran, Iran.
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11
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Aira M, Pérez-Losada M, Domínguez J. Diversity, structure and sources of bacterial communities in earthworm cocoons. Sci Rep 2018; 8:6632. [PMID: 29700426 PMCID: PMC5919978 DOI: 10.1038/s41598-018-25081-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 04/05/2018] [Indexed: 01/09/2023] Open
Abstract
Animals start interactions with the bacteria that will constitute their microbiomes at embryonic stage. After mating, earthworms produce cocoons externally which will be colonized with bacteria from their parents and the environment. Due to the key role bacterial symbionts play on earthworm fitness, it is important to study bacterial colonization during cocoon formation. Here we describe the cocoon microbiome of the earthworms Eisenia andrei and E. fetida, which included 275 and 176 bacterial species, respectively. They were dominated by three vertically-transmitted symbionts, Microbacteriaceae, Verminephrobacter and Ca. Nephrothrix, which accounted for 88% and 66% of the sequences respectively. Verminephrobacter and Ca. Nephrothrix showed a high rate of sequence variation, suggesting that they could be biparentally acquired during mating. The other bacterial species inhabiting the cocoons came from the bedding, where they accounted for a small fraction of the diversity (27% and 7% of bacterial species for E. andrei and E. fetida bedding). Hence, earthworm cocoon microbiome includes a large fraction of the vertically-transmitted symbionts and a minor fraction, but more diverse, horizontally and non-randomly acquired from the environment. These data suggest that horizontally-transmitted bacteria to cocoons may play an important role in the adaptation of earthworms to new environments or diets.
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Affiliation(s)
- Manuel Aira
- Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, Vigo, E-36310, Spain.
| | - Marcos Pérez-Losada
- CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, 4485-661, Vairão, Portugal.,Computational Biology Institute, Milken Institute School of Public Health, George Washington University, Ashburn, VA, 20147, USA
| | - Jorge Domínguez
- Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, Vigo, E-36310, Spain
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Lund MB, Mogensen MF, Marshall IPG, Albertsen M, Viana F, Schramm A. Genomic insights into the Agromyces-like symbiont of earthworms and its distribution among host species. FEMS Microbiol Ecol 2018; 94:4969677. [DOI: 10.1093/femsec/fiy068] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 04/11/2018] [Indexed: 01/09/2023] Open
Affiliation(s)
- Marie B Lund
- Section for Microbiology, Department of Bioscience, Aarhus University, Denmark Ny Munkegade 116 8000 Aarhus, Denmark
| | - Mathias F Mogensen
- Section for Microbiology, Department of Bioscience, Aarhus University, Denmark Ny Munkegade 116 8000 Aarhus, Denmark
| | - Ian P G Marshall
- Geomicrobiology, Section for Microbiology, Department of Bioscience, Aarhus University, Denmark, NyMunkegade 116, 8000 Aarhus, Denmark
| | - Mads Albertsen
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers vej 7H, 9220 Aalborg, Denmark
| | - Flávia Viana
- Section for Microbiology, Department of Bioscience, Aarhus University, Denmark Ny Munkegade 116 8000 Aarhus, Denmark
| | - Andreas Schramm
- Section for Microbiology, Department of Bioscience, Aarhus University, Denmark Ny Munkegade 116 8000 Aarhus, Denmark
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13
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Velmurugan P, Myung H, Govarthanan M, Yi YJ, Seo SK, Cho KM, Lovanh N, Oh BT. Production and characterization of bacterial cellulose by Leifsonia sp. CBNU-EW3 isolated from the earthworm, Eisenia fetida. BIOTECHNOL BIOPROC E 2015. [DOI: 10.1007/s12257-014-0793-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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14
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Møller P, Lund MB, Schramm A. Evolution of the tripartite symbiosis between earthworms, Verminephrobacter and Flexibacter-like bacteria. Front Microbiol 2015; 6:529. [PMID: 26074907 PMCID: PMC4445045 DOI: 10.3389/fmicb.2015.00529] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 05/13/2015] [Indexed: 12/15/2022] Open
Abstract
Nephridial (excretory organ) symbionts are widespread in lumbricid earthworms and the complexity of the nephridial symbiont communities varies greatly between earthworm species. The two most common symbionts are the well-described Verminephrobacter and less well-known Flexibacter-like bacteria. Verminephrobacter are present in almost all lumbricid earthworms, they are species-specific, vertically transmitted, and have presumably been associated with their hosts since the origin of lumbricids. Flexibacter-like symbionts have been reported from about half the investigated earthworms; they are also vertically transmitted. To investigate the evolution of this tri-partite symbiosis, phylogenies for 18 lumbricid earthworm species were constructed based on two mitochondrial genes, NADH dehydrogenase subunit 2 (ND2) and cytochrome c oxidase subunit I (COI), and compared to their symbiont phylogenies based on RNA polymerase subunit B (rpoB) and 16S rRNA genes. The two nephridial symbionts showed markedly different evolutionary histories with their hosts. For Verminephrobacter, clear signs of long-term host-symbiont co-evolution with rare host switching events confirmed its ancient association with lumbricid earthworms, likely dating back to their last common ancestor about 100 million years (MY) ago. In contrast, phylogenies for the Flexibacter-like symbionts suggested an ability to switch to new hosts, to which they adapted and subsequently became species-specific. Putative co-speciation events were only observed with closely related host species; on that basis, this secondary symbiosis was estimated to be minimum 45 MY old. Based on the monophyletic clustering of the Flexibacter-like symbionts, the low 16S rRNA gene sequence similarity to the nearest described species (<92%) and environmental sequences (<94.2%), and the specific habitat in the earthworm nephridia, we propose a new candidate genus for this group, Candidatus Nephrothrix.
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Affiliation(s)
- Peter Møller
- Section for Microbiology, Department of Bioscience, Aarhus University Aarhus, Denmark
| | - Marie B Lund
- Aarhus Institute of Advanced Studies, Aarhus University Aarhus, Denmark
| | - Andreas Schramm
- Section for Microbiology, Department of Bioscience, Aarhus University Aarhus, Denmark
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Heritable symbiosis: The advantages and perils of an evolutionary rabbit hole. Proc Natl Acad Sci U S A 2015; 112:10169-76. [PMID: 25713367 DOI: 10.1073/pnas.1421388112] [Citation(s) in RCA: 282] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Many eukaryotes have obligate associations with microorganisms that are transmitted directly between generations. A model for heritable symbiosis is the association of aphids, a clade of sap-feeding insects, and Buchnera aphidicola, a gammaproteobacterium that colonized an aphid ancestor 150 million years ago and persists in almost all 5,000 aphid species. Symbiont acquisition enables evolutionary and ecological expansion; aphids are one of many insect groups that would not exist without heritable symbiosis. Receiving less attention are potential negative ramifications of symbiotic alliances. In the short run, symbionts impose metabolic costs. Over evolutionary time, hosts evolve dependence beyond the original benefits of the symbiosis. Symbiotic partners enter into an evolutionary spiral that leads to irreversible codependence and associated risks. Host adaptations to symbiosis (e.g., immune-system modification) may impose vulnerabilities. Symbiont genomes also continuously accumulate deleterious mutations, limiting their beneficial contributions and environmental tolerance. Finally, the fitness interests of obligate heritable symbionts are distinct from those of their hosts, leading to selfish tendencies. Thus, genes underlying the host-symbiont interface are predicted to follow a coevolutionary arms race, as observed for genes governing host-pathogen interactions. On the macroevolutionary scale, the rapid evolution of interacting symbiont and host genes is predicted to accelerate host speciation rates by generating genetic incompatibilities. However, degeneration of symbiont genomes may ultimately limit the ecological range of host species, potentially increasing extinction risk. Recent results for the aphid-Buchnera symbiosis and related systems illustrate that, whereas heritable symbiosis can expand ecological range and spur diversification, it also presents potential perils.
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16
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Pass DA, Morgan AJ, Read DS, Field D, Weightman AJ, Kille P. The effect of anthropogenic arsenic contamination on the earthworm microbiome. Environ Microbiol 2014; 17:1884-96. [PMID: 25404571 DOI: 10.1111/1462-2920.12712] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 11/06/2014] [Accepted: 11/07/2014] [Indexed: 11/28/2022]
Abstract
Earthworms are globally distributed and perform essential roles for soil health and microbial structure. We have investigated the effect of an anthropogenic contamination gradient on the bacterial community of the keystone ecological species Lumbricus rubellus through utilizing 16S rRNA pyrosequencing for the first time to establish the microbiome of the host and surrounding soil. The earthworm-associated microbiome differs from the surrounding environment which appears to be a result of both filtering and stimulation likely linked to the altered environment associated with the gut micro-habitat (neutral pH, anoxia and increased carbon substrates). We identified a core earthworm community comprising Proteobacteria (∼50%) and Actinobacteria (∼30%), with lower abundances of Bacteroidetes (∼6%) and Acidobacteria (∼3%). In addition to the known earthworm symbiont (Verminephrobacter sp.), we identified a potential host-associated Gammaproteobacteria species (Serratia sp.) that was absent from soil yet observed in most earthworms. Although a distinct bacterial community defines these earthworms, clear family- and species-level modification were observed along an arsenic and iron contamination gradient. Several taxa observed in uncontaminated control microbiomes are suppressed by metal/metalloid field exposure, including eradication of the hereto ubiquitously associated Verminephrobacter symbiont, which raises implications to its functional role in the earthworm microbiome.
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Affiliation(s)
- Daniel Antony Pass
- Cardiff School of Biosciences, BIOSI 1, University of Cardiff, P.O. Box 915, Cardiff, Wales, CF10 3TL, UK
| | - Andrew John Morgan
- Cardiff School of Biosciences, BIOSI 1, University of Cardiff, P.O. Box 915, Cardiff, Wales, CF10 3TL, UK
| | - Daniel S Read
- Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Wallingford, Oxfordshire, OX10 8BB, UK
| | - Dawn Field
- Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Wallingford, Oxfordshire, OX10 8BB, UK
| | - Andrew J Weightman
- Cardiff School of Biosciences, BIOSI 1, University of Cardiff, P.O. Box 915, Cardiff, Wales, CF10 3TL, UK
| | - Peter Kille
- Cardiff School of Biosciences, BIOSI 1, University of Cardiff, P.O. Box 915, Cardiff, Wales, CF10 3TL, UK
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17
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Davidson SK, Dulla GF, Go RA, Stahl DA, Pinel N. Earthworm symbiont Verminephrobacter eiseniae mediates natural transformation within host egg capsules using type IV pili. Front Microbiol 2014; 5:546. [PMID: 25400622 PMCID: PMC4212676 DOI: 10.3389/fmicb.2014.00546] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 09/30/2014] [Indexed: 12/03/2022] Open
Abstract
The dense microbial communities commonly associated with plants and animals should offer many opportunities for horizontal gene transfer through described mechanisms of DNA exchange including natural transformation (NT). However, studies of the significance of NT have focused primarily on pathogens. The study presented here demonstrates highly efficient DNA exchange by NT in a common symbiont of earthworms. The obligate bacterial symbiont Verminephrobacter eiseniae is a member of a microbial consortium of the earthworm Eisenia fetida that is transmitted into the egg capsules to colonize the embryonic worms. In the study presented here, by testing for transformants under different conditions in culture, we demonstrate that V. eiseniae can incorporate free DNA from the environment, that competency is regulated by environmental factors, and that it is sequence specific. Mutations in the type IV pili of V. eiseniae resulted in loss of DNA uptake, implicating the type IV pilus (TFP) apparatus in DNA uptake. Furthermore, injection of DNA carrying antibiotic-resistance genes into egg capsules resulted in transformants within the capsule, demonstrating the relevance of DNA uptake within the earthworm system. The ability to take up species-specific DNA from the environment may explain the maintenance of the relatively large, intact genome of this long-associated obligate symbiont, and provides a mechanism for acquisition of foreign genes within the earthworm system.
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Affiliation(s)
- Seana K Davidson
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA USA
| | - Glenn F Dulla
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA USA
| | - Ruth A Go
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA USA
| | - David A Stahl
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA USA
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Stępniewska Z, Kuźniar A. Cultivation and detection of endophytic aerobic methanotrophs isolated from Sphagnum species as a perspective for environmental biotechnology. AMB Express 2014; 4:58. [PMID: 25401064 PMCID: PMC4230809 DOI: 10.1186/s13568-014-0058-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 06/24/2014] [Indexed: 01/06/2023] Open
Abstract
Enriched cultures of microorganisms are an essential step in the production of inoculum of these organisms for biotechnology and bioengineering. The potential application of methanotrophic microorganisms for removal of methane produced from landfills and coal mines as well as biodegradation of toxic compounds has been widely studied. Therefore, searching for new sources of methanotrophs can contribute to increasing the possibilities of biotechnology and bioengineering. Enrichment cultures of endophytic methanotrophs from Sphagnum sp. were initiated in NMS medium, a most widely used medium for cultivation of methanotrophic bacteria from various environments proposed in 1970 by Whittenbury. Incubation was carried out at 10, 20, 30, and 37°C with vigorous shaking on a shaker (180 rpm). The source of carbon and energy for endophytes were methane at the concentration range between 1-20%. It appeared that the consortium of endophytic bacteria grew only at the temperature of 20 and 30°C. During the culture of endophytes, the measurements of gas concentration showed a steady loss of methane and oxygen, as well as accumulation of carbon dioxide as a CH4 oxidation product. The use of FISH has made characterization of endophytic consortia possible. It turned out that the population of endophytes consists of type I and II methanotrophs as well as associated non-methanotrophic bacteria. Furthermore, we determined the potential of the examined bacteria for methane oxidation, which ranged up to 4,7 μMCH4 per ml of the population of endophytes per day.
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Affiliation(s)
- Zofia Stępniewska
- Department of Biochemistry and Environmental Chemistry, The John Paul II Catholic University of Lublin, Konstantynow 1I, Lublin, 20-708, Poland
| | - Agnieszka Kuźniar
- Department of Biochemistry and Environmental Chemistry, The John Paul II Catholic University of Lublin, Konstantynow 1I, Lublin, 20-708, Poland
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Lund MB, Kjeldsen KU, Schramm A. The earthworm-Verminephrobacter symbiosis: an emerging experimental system to study extracellular symbiosis. Front Microbiol 2014; 5:128. [PMID: 24734029 PMCID: PMC3975124 DOI: 10.3389/fmicb.2014.00128] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Accepted: 03/13/2014] [Indexed: 11/13/2022] Open
Abstract
Almost all Lumbricid earthworms (Oligochaeta: Lumbricidae) harbor extracellular species-specific bacterial symbionts of the genus Verminephrobacter (Betaproteobacteria) in their nephridia. The symbionts have a beneficial effect on host reproduction and likely live on their host's waste products. They are vertically transmitted and presumably associated with earthworms already at the origin of Lumbricidae 62–136 million years ago. The Verminephrobacter genomes carry signs of bottleneck-induced genetic drift, such as accelerated evolutionary rates, low codon usage bias, and extensive genome shuffling, which are characteristic of vertically transmitted intracellular symbionts. However, the Verminephrobacter genomes lack AT bias, size reduction, and pseudogenization, which are also common genomic hallmarks of vertically transmitted, intracellular symbionts. We propose that the opportunity for genetic mixing during part of the host—symbiont life cycle is the key to evade drift-induced genome erosion. Furthermore, we suggest the earthworm-Verminephrobacter association as a new experimental system for investigating host-microbe interactions, and especially for understanding genome evolution of vertically transmitted symbionts in the presence of genetic mixing.
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Affiliation(s)
- Marie B Lund
- Aarhus Institute of Advanced Studies, Aarhus University Aarhus, Denmark
| | - Kasper U Kjeldsen
- Section for Microbiology, Department of Bioscience, Center for Geomicrobiology, Aarhus University Aarhus, Denmark
| | - Andreas Schramm
- Section for Microbiology, Department of Bioscience, Aarhus University Aarhus, Denmark
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20
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Chandna P, Nain L, Singh S, Kuhad RC. Assessment of bacterial diversity during composting of agricultural byproducts. BMC Microbiol 2013; 13:99. [PMID: 23651653 PMCID: PMC3651732 DOI: 10.1186/1471-2180-13-99] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 04/18/2013] [Indexed: 11/30/2022] Open
Abstract
Background Composting is microbial decomposition of biodegradable materials and it is governed by physicochemical, physiological and microbiological factors. The importance of microbial communities (bacteria, actinomycetes and fungi) during composting is well established. However, the microbial diversity during composting may vary with the variety of composting materials and nutrient supplements. Therefore, it is necessary to study the diversity of microorganisms during composting of different agricultural byproducts like wheat bran, rice bran, rice husk, along with grass clippings and bulking agents. Here it has been attempted to assess the diversity of culturable bacteria during composting of agricultural byproducts. Results The culturable bacterial diversity was assessed during the process by isolating the most prominent bacteria. Bacterial population was found to be maximum during the mesophilic phase, but decreased during the thermophilic phase and declined further in the cooling and maturation phase of composting. The bacterial population ranged from 105 to 109 cfu g-1 compost. The predominant bacteria were characterized biochemically, followed by 16S rRNA gene sequencing. The isolated strains, both Gram-positive and Gram-negative groups belonged to the order Burkholderiales, Enterobacteriales, Actinobacteriales and Bacillales, which includes genera e.g. Staphylococcus, Serratia, Klebsiella, Enterobacter, Terribacillus, Lysinibacillus Kocuria, Microbacterium, Acidovorax and Comamonas. Genera like Kocuria, Microbacterium, Acidovorax, Comamonas and some new species of Bacillus were also identified for the first time from the compost made from agricultural byproducts. Conclusion The use of appropriate nitrogen amendments and bulking agents in composting resulted in good quality compost. The culture based strategy enabled us to isolate some novel bacterial isolates like Kocuria, Microbacterium, Acidovorax and Comamonas first time from agro-byproducts compost. These bacteria can be used as potential compost inoculants for accelerating composting process.
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Affiliation(s)
- Piyush Chandna
- Lignocellulose Biotechnology Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi 110 021, India
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21
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Rieder SR, Brunner I, Daniel O, Liu B, Frey B. Methylation of mercury in earthworms and the effect of mercury on the associated bacterial communities. PLoS One 2013; 8:e61215. [PMID: 23577209 PMCID: PMC3618111 DOI: 10.1371/journal.pone.0061215] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 03/07/2013] [Indexed: 11/24/2022] Open
Abstract
Methylmercury compounds are very toxic for most organisms. Here, we investigated the potential of earthworms to methylate inorganic-Hg. We hypothesized that the anaerobic and nutrient-rich conditions in the digestive tracts of earthworm's promote the methylation of Hg through the action of their gut bacteria. Earthworms were either grown in sterile soils treated with an inorganic (HgCl2) or organic (CH3HgCl) Hg source, or were left untreated. After 30 days of incubation, the total-Hg and methyl-Hg concentrations in the soils, earthworms, and their casts were analyzed. The impact of Hg on the bacterial community compositions in earthworms was also studied. Tissue concentrations of methyl-Hg in earthworms grown in soils treated with inorganic-Hg were about six times higher than in earthworms grown in soils without Hg. Concentrations of methyl-Hg in the soils and earthworm casts remained at significantly lower levels suggesting that Hg was mainly methylated in the earthworms. Bacterial communities in earthworms were mostly affected by methyl-Hg treatment. Terminal-restriction fragments (T-RFs) affiliated to Firmicutes were sensitive to inorganic and methyl-Hg, whereas T-RFs related to Betaproteobacteria were tolerant to the Hg treatments. Sulphate-reducing bacteria were detected in earthworms but not in soils.
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Affiliation(s)
- Stephan Raphael Rieder
- Rhizosphere Processes Group, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
- Institute for Biogeochemistry and Pollutant Dynamics, ETH Zürich, Zürich, Switzerland
| | - Ivano Brunner
- Rhizosphere Processes Group, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | - Otto Daniel
- Ecotoxicology Group, Agroscope Changins-Wädenswil, Wädenswil, Switzerland
| | - Bian Liu
- Medicine-Pulmonary, Allergy and Critical Care, Columbia University, New York, New York, United States
| | - Beat Frey
- Rhizosphere Processes Group, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
- * E-mail:
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22
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Gold biomineralization by a metallophore from a gold-associated microbe. Nat Chem Biol 2013; 9:241-3. [PMID: 23377039 DOI: 10.1038/nchembio.1179] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2012] [Accepted: 01/07/2013] [Indexed: 11/08/2022]
Abstract
Microorganisms produce and secrete secondary metabolites to assist in their survival. We report that the gold resident bacterium Delftia acidovorans produces a secondary metabolite that protects from soluble gold through the generation of solid gold forms. This finding is the first demonstration that a secreted metabolite can protect against toxic gold and cause gold biomineralization.
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Davidson SK, Powell R, James S. A global survey of the bacteria within earthworm nephridia. Mol Phylogenet Evol 2012; 67:188-200. [PMID: 23268186 DOI: 10.1016/j.ympev.2012.12.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 11/29/2012] [Accepted: 12/06/2012] [Indexed: 11/18/2022]
Abstract
Earthworms comprise 16 described families in the Crassiclitellata plus a few other minor groups. Microscopy studies of the early 20th century detected bacteria within the excretory organs, the nephridia, of species within a few of these families. More recent evidence for the consistent and specific association of bacteria with nephridia within the Lumbricidae has been well documented, but the presence and identity of nephridial bacteria among the rest of the Crassiclitellata families had not been explored. The study presented here aimed to identify members of Crassiclitellata families that harbor bacteria in their nephridia, and identify these bacteria based on 16S rRNA gene sequences. Eleven earthworm families were surveyed from countries of six continents, and two island nations. The results revealed members of four bacterial orders commonly occurred within nephridia of genera within nine Crassiclitellata families. Members of the bacterial phyla Bacteroidetes (order Sphingobacteriales), Betaproteobacteria (order Burkholderiales; family Comamonadaceae), and Alphaproteobacteria (orders Rhodospirillales and Rhizobiales) were detected in the nephridia of basal Crassiclitellata, as well as in derived families. Earthworm genera with meronephridia, multiple small nephridia per segment, lacked bacteria, whereas bacteria were often detected in holonephridia, single pairs of large nephridia with a distinct morphology and external excretory pore. The Acanthodrilidae members, a large derived family of earthworms, did not appear to possess nephridial bacteria regardless of nephridial form. Although earthworms from a variety of habitat types were sampled, there were no clear correlations of lifestyle with symbiont types, with the exception of the aquatic earthworms that contained bacteria unrelated to those in any other earthworms. The findings support an evolutionarily long association of bacteria within the Crassiclitellata, and suggest a contribution to nitrogen conservation for the earthworms.
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Affiliation(s)
- Seana K Davidson
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA 98195-5014, USA.
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Abstract
This review outlines information about the Gram-negative, aerobic bacterium Variovorax paradoxus. The genomes of these species have G+C contents of 66.5-69.4 mol%, and the cells form yellow colonies. Some strains of V. paradoxus are facultative lithoautotrophic, others are chemoorganotrophic. Many of them are associated with important catabolic processes including the degradation of toxic and/or complex chemical compounds. The degradation pathways or other skills related to the following compounds, respectively, are described in this review: sulfolane, 3-sulfolene, 2-mercaptosuccinic acid, 3,3'-thiodipropionic acid, aromatic sulfonates, alkanesulfonates, amino acids and other sulfur sources, polychlorinated biphenyls, dimethyl terephthalate, linuron, 2,4-dinitrotoluene, homovanillate, veratraldehyde, 2,4-dichlorophenoxyacetic acid, anthracene, poly(3-hydroxybutyrate), chitin, cellulose, humic acids, metal-EDTA complexes, yttrium, rare earth elements, As(III), trichloroethylene, capsaicin, 3-nitrotyrosine, acyl-homoserine lactones, 1-aminocyclopropane-1-carboxylate, methyl tert-butyl ether, geosmin, and 2-methylisoborneol. Strains of V. paradoxus are also engaged in mutually beneficial interactions with other plant and bacterial species in various ecosystems. This species comprises probably promising strains for bioremediation and other biotechnical applications. Lately, the complete genomes of strains S110 and EPS have been sequenced for further investigations.
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Saha S, Hunter WB, Reese J, Morgan JK, Marutani-Hert M, Huang H, Lindeberg M. Survey of endosymbionts in the Diaphorina citri metagenome and assembly of a Wolbachia wDi draft genome. PLoS One 2012; 7:e50067. [PMID: 23166822 PMCID: PMC3500351 DOI: 10.1371/journal.pone.0050067] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 10/17/2012] [Indexed: 02/03/2023] Open
Abstract
Diaphorina citri (Hemiptera: Psyllidae), the Asian citrus psyllid, is the insect vector of Ca. Liberibacter asiaticus, the causal agent of citrus greening disease. Sequencing of the D. citri metagenome has been initiated to gain better understanding of the biology of this organism and the potential roles of its bacterial endosymbionts. To corroborate candidate endosymbionts previously identified by rDNA amplification, raw reads from the D. citri metagenome sequence were mapped to reference genome sequences. Results of the read mapping provided the most support for Wolbachia and an enteric bacterium most similar to Salmonella. Wolbachia-derived reads were extracted using the complete genome sequences for four Wolbachia strains. Reads were assembled into a draft genome sequence, and the annotation assessed for the presence of features potentially involved in host interaction. Genome alignment with the complete sequences reveals membership of Wolbachia wDi in supergroup B, further supported by phylogenetic analysis of FtsZ. FtsZ and Wsp phylogenies additionally indicate that the Wolbachia strain in the Florida D. citri isolate falls into a sub-clade of supergroup B, distinct from Wolbachia present in Chinese D. citri isolates, supporting the hypothesis that the D. citri introduced into Florida did not originate from China.
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Affiliation(s)
- Surya Saha
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Wayne B. Hunter
- USDA-ARS, U.S. Horticultural Research Laboratory, Fort Pierce, Florida, United States of America
| | - Justin Reese
- Genformatic, LLC., Alpharetta, Georgia, United States of America
| | - J. Kent Morgan
- USDA-ARS, U.S. Horticultural Research Laboratory, Fort Pierce, Florida, United States of America
| | - Mizuri Marutani-Hert
- USDA-ARS, U.S. Horticultural Research Laboratory, Fort Pierce, Florida, United States of America
| | - Hong Huang
- School of Information, University of South Florida, Tampa, Florida, United States of America
| | - Magdalen Lindeberg
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
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List of new names and new combinations previously effectively, but not validly, published. Int J Syst Evol Microbiol 2012. [DOI: 10.1099/ijs.0.048033-0] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The purpose of this announcement is to effect the valid publication of the following effectively published new names and new combinations under the procedure described in the Bacteriological Code (1990 Revision). Authors and other individuals wishing to have new names and/or combinations included in future lists should send three copies of the pertinent reprint or photocopies thereof, or an electronic copy of the published paper, to the IJSEM Editorial Office for confirmation that all of the other requirements for valid publication have been met. It is also a requirement of IJSEM and the ICSP that authors of new species, new subspecies and new combinations provide evidence that types are deposited in two recognized culture collections in two different countries. It should be noted that the date of valid publication of these new names and combinations is the date of publication of this list, not the date of the original publication of the names and combinations. The authors of the new names and combinations are as given below, and these authors’ names will be included in the author index of the present issue. Inclusion of a name on these lists validates the publication of the name and thereby makes it available in bacteriological nomenclature. The inclusion of a name on this list is not to be construed as taxonomic acceptance of the taxon to which the name is applied. Indeed, some of these names may, in time, be shown to be synonyms, or the organisms may be transferred to another genus, thus necessitating the creation of a new combination.
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Pathma J, Sakthivel N. Microbial diversity of vermicompost bacteria that exhibit useful agricultural traits and waste management potential. SPRINGERPLUS 2012; 1:26. [PMID: 23961356 PMCID: PMC3725894 DOI: 10.1186/2193-1801-1-26] [Citation(s) in RCA: 154] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 09/28/2012] [Indexed: 11/17/2022]
Abstract
Vermicomposting is a non-thermophilic, boioxidative process that involves earthworms and associated microbes. This biological organic waste decomposition process yields the biofertilizer namely the vermicompost. Vermicompost is a finely divided, peat like material with high porosity, good aeration, drainage, water holding capacity, microbial activity, excellent nutrient status and buffering capacity thereby resulting the required physiochemical characters congenial for soil fertility and plant growth. Vermicompost enhances soil biodiversity by promoting the beneficial microbes which inturn enhances plant growth directly by production of plant growth-regulating hormones and enzymes and indirectly by controlling plant pathogens, nematodes and other pests, thereby enhancing plant health and minimizing the yield loss. Due to its innate biological, biochemical and physiochemical properties, vermicompost may be used to promote sustainable agriculture and also for the safe management of agricultural, industrial, domestic and hospital wastes which may otherwise pose serious threat to life and environment.
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Affiliation(s)
- Jayakumar Pathma
- Department of Biotechnology School of Life Sciences, Pondicherry University, Kalapet, Puducherry, 605014 India
| | - Natarajan Sakthivel
- Department of Biotechnology School of Life Sciences, Pondicherry University, Kalapet, Puducherry, 605014 India
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Ni B, Zhang Y, Chen DW, Wang BJ, Liu SJ. Assimilation of aromatic compounds by Comamonas testosteroni: characterization and spreadability of protocatechuate 4,5-cleavage pathway in bacteria. Appl Microbiol Biotechnol 2012; 97:6031-41. [DOI: 10.1007/s00253-012-4402-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 08/25/2012] [Accepted: 08/29/2012] [Indexed: 10/27/2022]
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Dulla GFJ, Go RA, Stahl DA, Davidson SK. Verminephrobacter eiseniae type IV pili and flagella are required to colonize earthworm nephridia. THE ISME JOURNAL 2012; 6:1166-75. [PMID: 22170422 PMCID: PMC3358029 DOI: 10.1038/ismej.2011.183] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 10/31/2011] [Accepted: 11/03/2011] [Indexed: 11/08/2022]
Abstract
The bacterial symbiont Verminephrobacter eiseniae colonizes nephridia, the excretory organs, of the lumbricid earthworm Eisenia fetida. E. fetida transfers V. eisenia into the egg capsule albumin during capsule formation and V. eiseniae cells migrate into the earthworm nephridia during embryogenesis, where they bind and persist. In order to characterize the mechanistic basis of selective tissue colonization, methods for site-directed mutagenesis and colonization competence were developed and used to evaluate the consequences of individual gene disruptions. Using these newly developed tools, two distinct modes of bacterial motility were shown to be required for V. eiseniae colonization of nascent earthworm nephridia. Flagella and type IV pili mutants lacked motility in culture and were not able to colonize embryonic earthworms, indicating that both twitching and flagellar motility are required for entrance into the nephridia.
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Affiliation(s)
- Glenn F J Dulla
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA
| | - Ruth A Go
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA
| | - David A Stahl
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA
| | - Seana K Davidson
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA
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Kjeldsen KU, Bataillon T, Pinel N, De Mita S, Lund MB, Panitz F, Bendixen C, Stahl DA, Schramm A. Purifying selection and molecular adaptation in the genome of Verminephrobacter, the heritable symbiotic bacteria of earthworms. Genome Biol Evol 2012; 4:307-15. [PMID: 22333491 PMCID: PMC3318438 DOI: 10.1093/gbe/evs014] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
While genomic erosion is common among intracellular symbionts, patterns of genome evolution in heritable extracellular endosymbionts remain elusive. We study vertically transmitted extracellular endosymbionts (Verminephrobacter, Betaproteobacteria) that form a beneficial, species-specific, and evolutionarily old (60–130 Myr) association with earthworms. We assembled a draft genome of Verminephrobacter aporrectodeae and compared it with the genomes of Verminephrobacter eiseniae and two nonsymbiotic close relatives (Acidovorax). Similar to V. eiseniae, the V. aporrectodeae genome was not markedly reduced in size and showed no A–T bias. We characterized the strength of purifying selection (ω = dN/dS) and codon usage bias in 876 orthologous genes. Symbiont genomes exhibited strong purifying selection (ω = 0.09 ± 0.07), although transition to symbiosis entailed relaxation of purifying selection as evidenced by 50% higher ω values and less codon usage bias in symbiont compared with reference genomes. Relaxation was not evenly distributed among functional gene categories but was overrepresented in genes involved in signal transduction and cell envelope biogenesis. The same gene categories also harbored instances of positive selection in the Verminephrobacter clade. In total, positive selection was detected in 89 genes, including also genes involved in DNA metabolism, tRNA modification, and TonB-dependent iron uptake, potentially highlighting functions important in symbiosis. Our results suggest that the transition to symbiosis was accompanied by molecular adaptation, while purifying selection was only moderately relaxed, despite the evolutionary age and stability of the host association. We hypothesize that biparental transmission of symbionts and rare genetic mixing during transmission can prevent genome erosion in heritable symbionts.
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Verminephrobacter aporrectodeae sp. nov. subsp. tuberculatae and subsp. caliginosae, the specific nephridial symbionts of the earthworms Aporrectodea tuberculata and A. caliginosa. Antonie van Leeuwenhoek 2011; 101:507-14. [PMID: 22041977 DOI: 10.1007/s10482-011-9659-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 10/11/2011] [Indexed: 10/16/2022]
Abstract
Clone library-based studies have shown that almost all lumbricid earthworm species harbour host-specific symbiotic bacteria belonging to the novel genus Verminephrobacter in their nephridia (excretory organs). To date the only described representative from this genus is Verminephrobacter eiseniae, the specific symbiont of the earthworm Eisenia fetida. In this study two novel rod-shaped, non-endosporeforming, betaproteobacterial symbionts were isolated from the nephridia of two closely related earthworm species. Both isolates were affiliated with the genus Verminephrobacter by 16S rRNA gene sequence analysis. Similarly to V. eiseniae, the two isolates grew aerobically with a preference for low oxygen concentrations on a range of sugars, fatty acids and amino acids and fermentatively on glucose and pyruvate. These phenotypes match well with the conditions reported or inferred for the nephridial environment. Based on 16S rRNA gene similarity, DNA-DNA hybridization value and phenotypic characteristics the two isolates are clearly distinct from V. eiseniae. Phenotypic characteristics could not clearly differentiate the two strains as separate species but a low DNA-DNA hybridization value of 57.3%, their earthworm host specificity, differing temperature ranges and pH optima suggest that they represent two subspecies of a novel species of Verminephrobacter. For this species, the name V. aporrectodeae sp. nov. is proposed, with the two subspecies V. aporrectodeae subsp. tuberculatae (type strain, At4(T) = DSM 21361(T) = LMG 25313(T)) and V. aporrectodeae subsp. caliginosae (type strain, Ac9(T) = DSM 21895(T) = LMG 25312(T)) isolated from the nephridia of the earthworms Aporrectodea tuberculata and A. caliginosa, respectively.
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Nanopods: a new bacterial structure and mechanism for deployment of outer membrane vesicles. PLoS One 2011; 6:e20725. [PMID: 21687732 PMCID: PMC3110197 DOI: 10.1371/journal.pone.0020725] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 05/10/2011] [Indexed: 12/11/2022] Open
Abstract
Background Bacterial outer membrane vesicles (OMV) are packets of periplasmic material that, via the proteins and other molecules they contain, project metabolic function into the environment. While OMV production is widespread in proteobacteria, they have been extensively studied only in pathogens, which inhabit fully hydrated environments. However, many (arguably most) bacterial habitats, such as soil, are only partially hydrated. In the latter, water is characteristically distributed as films on soil particles that are, on average thinner, than are typical OMV (ca. ≤10 nm water film vs. 20 to >200 nm OMV;). Methodology/Principal Findings We have identified a new bacterial surface structure, termed a “nanopod”, that is a conduit for projecting OMV significant distances (e.g., ≥6 µm) from the cell. Electron cryotomography was used to determine nanopod three-dimensional structure, which revealed chains of vesicles within an undulating, tubular element. By using immunoelectron microscopy, proteomics, heterologous expression and mutagenesis, the tubes were determined to be an assembly of a surface layer protein (NpdA), and the interior structures identified as OMV. Specific metabolic function(s) for nanopods produced by Delftia sp. Cs1-4 are not yet known. However, a connection with phenanthrene degradation is a possibility since nanopod formation was induced by growth on phenanthrene. Orthologs of NpdA were identified in three other genera of the Comamonadaceae family, and all were experimentally verified to form nanopods. Conclusions/Significance Nanopods are new bacterial organelles, and establish a new paradigm in the mechanisms by which bacteria effect long-distance interactions with their environment. Specifically, they create a pathway through which cells can effectively deploy OMV, and the biological activity these transmit, in a diffusion-independent manner. Nanopods would thus allow environmental bacteria to expand their metabolic sphere of influence in a manner previously unknown for these organisms.
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Cortada L, Sakai H, Verdejo-Lucas S, Mizukubo T. Meloidogyne virulence locus molecular marker for characterization of selected mi-virulent populations of Meloidogyne spp. is correlated with several genera of betaproteobacteria. PHYTOPATHOLOGY 2011; 101:410-415. [PMID: 20955082 DOI: 10.1094/phyto-04-10-0123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Resistance to root-knot nematodes in tomato is conferred by the Mi resistance gene to the three most important species of Meloidogyne: M. arenaria, M. incognita, and M. javanica. Nevertheless, the Mi gene is unable to inhibit the reproduction of selected and naturally Mi-virulent populations of root-knot nematodes. As pathogenicity assays are time consuming, molecular markers were developed for the easy identification of Mi-virulent populations of Meloidogyne. The sequence characterized amplified region-Meloidogyne virulence locus (MVC) molecular marker is reported to differentiate Mi-avirulent and naturally Mi-virulent from selected Mi-virulent populations. This marker was used to compare acquired virulence in populations of M. javanica from Spain. The original populations used to develop the MVC marker were included as control for reference. Results showed that this marker did not amplify genomic DNA extracted from single juveniles or females of any of the populations tested either from Spain or Japan. In silico analyses performed with the recently published complete genome of M. incognita, indicated that the MVC marker is not correlated to a MVC or to any eukaryotic organism but to several betaproteobacteria genus from the family Comamonadaceae.
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Affiliation(s)
- Laura Cortada
- IRTA, Patología Vegetal, Crta. de Cabrils Km 2, 08348 Cabrils, Barcelona, Spain.
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Phylogeny of replication initiator protein TrfA reveals a highly divergent clade of incompatibility group P1 plasmids. Appl Environ Microbiol 2011; 77:2522-6. [PMID: 21296948 DOI: 10.1128/aem.02789-10] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Incompatibility group P1 (IncP-1) plasmid diversity was evaluated based on replication initiator protein (TrfA) phylogeny. A new and highly divergent clade was identified. Replication assays indicated that TrfA of recently discovered IncP-1 plasmids from Xylella fastidiosa and Verminephrobacter eiseniae initiated plasmid replication using cognate or heterologous origins of replication.
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Stock SP, Bordenstein SR, Odden J, Oldenburg D, Reznikoff W, Werren JH, Selosse MA. Symbiosis instruction: considerations from the education workshop at the 6th ISS Congress. Symbiosis 2010. [DOI: 10.1007/s13199-010-0077-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Beneficial effect of Verminephrobacter nephridial symbionts on the fitness of the earthworm Aporrectodea tuberculata. Appl Environ Microbiol 2010; 76:4738-43. [PMID: 20511426 DOI: 10.1128/aem.00108-10] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Almost all lumbricid earthworms (Oligochaeta: Lumbricidae) harbor species-specific Verminephrobacter (Betaproteobacteria) symbionts in their nephridia (excretory organs). The function of the symbiosis, and whether the symbionts have a beneficial effect on their earthworm host, is unknown; however, the symbionts have been hypothesized to enhance nitrogen retention in earthworms. The effect of Verminephrobacter on the life history traits of the earthworm Aporrectodea tuberculata (Eisen) was investigated by comparing the growth, development, and fecundity of worms with and without symbionts given high (cow dung)- and low (straw)-nutrient diets. There were no differences in worm growth or the number of cocoons produced by symbiotic and aposymbiotic worms. Worms with Verminephrobacter symbionts reached sexual maturity earlier and had higher cocoon hatching success than worms cured of their symbionts when grown on the low-nutrient diet. Thus, Verminephrobacter nephridial symbionts do have a beneficial effect on their earthworm host. Cocoons with and without symbionts did not significantly differ in total organic carbon, total nitrogen, or total hydrolyzable amino acid content, which strongly questions the hypothesized role of the symbionts in nitrogen recycling for the host.
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Davidson SK, Powell RJ, Stahl DA. Transmission of a bacterial consortium in Eisenia fetida egg capsules. Environ Microbiol 2010; 12:2277-88. [PMID: 21966919 DOI: 10.1111/j.1462-2920.2010.02231.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The earthworm Eisenia fetida harbours Verminephrobacter eiseniae within their excretory nephridia. This symbiont is transferred from the parent into the egg capsules where the cells are acquired by the developing earthworm in a series of recruitment steps. Previous studies defined V. eiseniae as the most abundant cell type in the egg capsules, leaving approximately 30% of the bacteria unidentified and of unknown origin. The study presented here used terminal restriction fragment length polymorphism analysis together with cloning and sequencing of 16S rRNA genes to define the composition of the bacterial consortium in E. fetida egg capsules from early to late development. Newly formed capsules of E. fetida contained three bacterial types, a novel Microbacteriaceae member, a Flexibacteriaceae member and the previously described V. eiseniae. Fluorescent in situ hybridization (FISH) using specific and general rRNA probes demonstrated that the bacteria are abundant during early development, colonize the embryo and appear in the adult nephridia. As the capsules mature, Herbaspirillum spp. become abundant although they were not detected within the adult worm. These divergent taxa could serve distinct functions in both the adult earthworm and in the egg capsule to influence the competitive ability of earthworms within the soil community.
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Affiliation(s)
- Seana K Davidson
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA 98195-5014, USA.
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Chaston J, Goodrich-Blair H. Common trends in mutualism revealed by model associations between invertebrates and bacteria. FEMS Microbiol Rev 2010; 34:41-58. [PMID: 19909347 PMCID: PMC2794943 DOI: 10.1111/j.1574-6976.2009.00193.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Mutually beneficial interactions between microorganisms and animals are a conserved and ubiquitous feature of biotic systems. In many instances animals, including humans, are dependent on their microbial associates for nutrition, defense, or development. To maintain these vital relationships, animals have evolved processes that ensure faithful transmission of specific microbial symbionts between generations. Elucidating mechanisms of transmission and symbiont specificity has been aided by the study of experimentally tractable invertebrate animals with diverse and highly evolved associations with microorganisms. Here, we review several invertebrate model systems that contribute to our current understanding of symbiont transmission, recognition, and specificity. Although the details of transmission and symbiont selection vary among associations, comparisons of diverse mutualistic associations are revealing a number of common themes, including restriction of symbiont diversity during transmission and glycan-lectin interactions during partner selection and recruitment.
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Affiliation(s)
- John Chaston
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
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Lund MB, Davidson SK, Holmstrup M, James S, Kjeldsen KU, Stahl DA, Schramm A. Diversity and host specificity of the Verminephrobacter-earthworm symbiosis. Environ Microbiol 2009; 12:2142-51. [PMID: 21966909 DOI: 10.1111/j.1462-2920.2009.02084.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Symbiotic bacteria of the genus Verminephrobacter (Betaproteobacteria) were detected in the nephridia of 19 out of 23 investigated earthworm species (Oligochaeta: Lumbricidae) by 16S rRNA gene sequence analysis and fluorescence in situ hybridization (FISH). While all four Lumbricus species and three out of five Aporrectodea species were densely colonized by a mono-species culture of Verminephrobacter, other earthworm species contained mixed bacterial populations with varying proportions of Verminephrobacter; four species did not contain Verminephrobacter at all. The Verminephrobacter symbionts could be grouped into earthworm species-specific sequence clusters based on their 16S rRNA and RNA polymerase subunit B (rpoB) genes. Closely related host species harboured more closely related symbionts than did distantly related hosts. Co-diversification of the symbiotic partners could not be demonstrated unambiguously due to the poor resolution of the host phylogeny [based on histone H3 and cytochrome c oxidase subunit I (COI) gene sequence analyses]. However, there was a pattern of symbiont diversification within four groups of closely related hosts. The mean rate of symbiont 16S rRNA gene evolution was determined using a relaxed clock model, and the rate was calibrated with paleogeographical estimates of the time of origin of Lumbricid earthworms. The calibrated rates of symbiont 16S rRNA gene evolution are 0.012-0.026 substitutions per site per 50 million years and thus similar to rates reported from other symbiotic bacteria.
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Affiliation(s)
- Marie B Lund
- Department of Biological Sciences, Microbiology, Aarhus University, Aarhus, Denmark
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Kikuchi Y, Bomar L, Graf J. Stratified bacterial community in the bladder of the medicinal leech, Hirudo verbana. Environ Microbiol 2009; 11:2758-70. [PMID: 19678832 DOI: 10.1111/j.1462-2920.2009.02004.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Most animals harbour symbiotic microorganisms inside their body, where intimate interactions occur between the partners. The medicinal leech, Hirudo verbana, possesses 17 pairs of excretory bladders that harbour a large number of intracellular and extracellular symbiotic bacteria. In this study, we characterized the bladder symbionts using molecular phylogenetic analyses, transmission electron microscopy (TEM) and fluorescence in situ hybridization (FISH). Restriction fragment length polymorphism (RFLP) and sequence analyses of 16S rRNA gene clone libraries suggested that six bacterial species co-colonize the leech bladders. Phylogenetic analyses revealed that these species belong to the alpha-Proteobacteria (Ochrobactrum symbiont), beta-Proteobacteria (Beta-1 and Beta-2 symbionts), delta-Proteobacteria (Bdellovibrio symbiont) and Bacteroidetes (Niabella and Sphingobacterium symbionts). Species-specific PCR detection and FISH confirmed the localization of the symbiotic bacteria in the bladders. The Ochrobactrum, Beta-1, Bdellovibrio and Sphingobacterium symbionts were consistently detected in 13 leeches from two populations, while infection rate of the other symbionts ranged between 20% and 100% in the two leech populations. Transmission electron microscopy observations of the bladders revealed epithelial cells harbouring a number of intracellular bacilli and an additional type of extracellular, rod-shaped bacteria in the luminal region. Fluorescence in situ hybridization with group-specific oligonucleotide probes revealed the spatial organization of the bacterial species in the bladder: the Ochrobactrum symbiont was located intracellularly inside epithelial cells; the Bacteroidetes were localized close to the epithelium in the lumen of the bladder; and the Bacteroidetes layer was covered with dense beta-proteobacterial cells. These results clearly demonstrate that a simple but organized microbial community exists in the bladder of the medicinal leech.
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MESH Headings
- Animals
- Bacteroidetes/genetics
- Bacteroidetes/isolation & purification
- Bacteroidetes/ultrastructure
- Biodiversity
- DNA, Bacterial/genetics
- DNA, Bacterial/isolation & purification
- In Situ Hybridization, Fluorescence
- Leeches/microbiology
- Leeches/ultrastructure
- Microscopy, Electron, Transmission
- Phylogeny
- Polymorphism, Restriction Fragment Length
- Proteobacteria/genetics
- Proteobacteria/isolation & purification
- Proteobacteria/ultrastructure
- RNA, Ribosomal, 16S/analysis
- RNA, Ribosomal, 16S/genetics
- Sequence Analysis, DNA
- Species Specificity
- Symbiosis
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Affiliation(s)
- Yoshitomo Kikuchi
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA
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Davidson SK, Stahl DA. Selective recruitment of bacteria during embryogenesis of an earthworm. ISME JOURNAL 2008; 2:510-8. [DOI: 10.1038/ismej.2008.16] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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