Characterization of methanogenic and prokaryotic assemblages based onmcrAand 16S rRNA gene diversity in sediments of the Kazan mud volcano (Mediterranean Sea)

Geobiology ◽  
2008 ◽  
Vol 6 (5) ◽  
pp. 450-460 ◽  
Author(s):  
K. A. KORMAS ◽  
A. MEZITI ◽  
A. DÄHLMANN ◽  
G. J. DE LANGE ◽  
V. LYKOUSIS
LWT ◽  
2021 ◽  
Vol 147 ◽  
pp. 111579
Author(s):  
Creciana M. Endres ◽  
Ícaro Maia S. Castro ◽  
Laura D. Trevisol ◽  
Juliana M. Severo ◽  
Michele B. Mann ◽  
...  

Microbiology ◽  
2010 ◽  
Vol 156 (7) ◽  
pp. 2080-2091 ◽  
Author(s):  
Anne-Laure Michon ◽  
Fabien Aujoulat ◽  
Laurent Roudière ◽  
Olivier Soulier ◽  
Isabelle Zorgniotti ◽  
...  

As well as intraspecific heterogeneity, intragenomic heterogeneity between 16S rRNA gene copies has been described for a range of bacteria. Due to the wide use of 16S rRNA gene sequence analysis for taxonomy, identification and metagenomics, evaluating the extent of these heterogeneities in natural populations is an essential prerequisite. We investigated inter- and intragenomic 16S rRNA gene heterogeneity of the variable region V3 in a population of 149 clinical isolates of Veillonella spp. of human origin and in 13 type or reference Veillonella strains using PCR-temporal temperature gel electrophoresis (TTGE). 16S rRNA gene diversity was high in the studied population, as 45 different banding patterns were observed. Intragenomic heterogeneity was demonstrated for 110 (74 %) isolates and 8 (61.5 %) type or reference strains displaying two or three different gene copies. Polymorphic nucleotide positions accounted for 0.5–2.5 % of the sequence and were scattered in helices H16 and H17 of the rRNA molecule. Some of them changed the secondary structure of H17. Phylotaxonomic structure of the population based on the single-copy housekeeping gene rpoB was compared with TTGE patterns. The intragenomic V3 heterogeneity, as well as recombination events between strains or isolates of different rpoB clades, impaired the 16S rRNA-based identification for some Veillonella species. Such approaches should be conducted in other bacterial populations to optimize the interpretation of 16S rRNA gene sequences in taxonomy and/or diversity studies.


2008 ◽  
Vol 74 (10) ◽  
pp. 3198-3215 ◽  
Author(s):  
Enoma O. Omoregie ◽  
Vincent Mastalerz ◽  
Gert de Lange ◽  
Kristina L. Straub ◽  
Andreas Kappler ◽  
...  

ABSTRACT In this study we determined the composition and biogeochemistry of novel, brightly colored, white and orange microbial mats at the surface of a brine seep at the outer rim of the Chefren mud volcano. These mats were interspersed with one another, but their underlying sediment biogeochemistries differed considerably. Microscopy revealed that the white mats were granules composed of elemental S filaments, similar to those produced by the sulfide-oxidizing epsilonproteobacterium “Candidatus Arcobacter sulfidicus.” Fluorescence in situ hybridization indicated that microorganisms targeted by a “Ca. Arcobacter sulfidicus”-specific oligonucleotide probe constituted up to 24% of the total the cells within these mats. Several 16S rRNA gene sequences from organisms closely related to “Ca. Arcobacter sulfidicus” were identified. In contrast, the orange mat consisted mostly of bright orange flakes composed of empty Fe(III) (hydr)oxide-coated microbial sheaths, similar to those produced by the neutrophilic Fe(II)-oxidizing betaproteobacterium Leptothrix ochracea. None of the 16S rRNA gene sequences obtained from these samples were closely related to sequences of known neutrophilic aerobic Fe(II)-oxidizing bacteria. The sediments below both types of mats showed relatively high sulfate reduction rates (300 nmol·cm−3·day−1) partially fueled by the anaerobic oxidation of methane (10 to 20 nmol·cm−3·day−1). Free sulfide produced below the white mat was depleted by sulfide oxidation within the mat itself. Below the orange mat free Fe(II) reached the surface layer and was depleted in part by microbial Fe(II) oxidation. Both mats and the sediments underneath them hosted very diverse microbial communities and contained mineral precipitates, most likely due to differences in fluid flow patterns.


2006 ◽  
Vol 56 (8) ◽  
pp. 1883-1887 ◽  
Author(s):  
Laurent Urios ◽  
Hélène Agogué ◽  
Françoise Lesongeur ◽  
Erko Stackebrandt ◽  
Philippe Lebaron

A novel aerobic, Gram-negative bacterium, named 13IX/A01/164T, was isolated from surface waters in the coastal north-western Mediterranean Sea. Cells were motile, straight rods, 2.5 μm long and 0.2 μm wide, and formed orange colonies on marine agar medium. The G+C content of the genomic DNA of strain 13IX/A01/164T was 42 mol%. Phylogenetic analysis of the 16S rRNA gene sequence placed the strain in the phylum Bacteroidetes within the family Crenotrichaceae. On the basis of 16S rRNA gene sequence comparison and physiological and biochemical characteristics, this isolate represents a novel species of a new genus, for which the name Balneola vulgaris gen. nov., sp. nov. is proposed. The type strain of Balneola vulgaris is 13IX/A01/164T (=DSM 17893T=CIP 109092T=OOB 256T).


2008 ◽  
Vol 46 (2) ◽  
pp. 125-136 ◽  
Author(s):  
Young-Do Nam ◽  
Youlboong Sung ◽  
Ho-Won Chang ◽  
Seong Woon Roh ◽  
Kyoung-Ho Kim ◽  
...  

2017 ◽  
Vol 84 (3) ◽  
Author(s):  
Irene Cano ◽  
Ronny van Aerle ◽  
Stuart Ross ◽  
David W. Verner-Jeffreys ◽  
Richard K. Paley ◽  
...  

ABSTRACTOne of the fastest growing fisheries in the UK is the king scallop (Pecten maximusL.), also currently rated as the second most valuable fishery. Mass mortality events in scallops have been reported worldwide, often with the causative agent(s) remaining uncharacterized. In May 2013 and 2014, two mass mortality events affecting king scallops were recorded in the Lyme Bay marine protected area (MPA) in Southwest England. Histopathological examination showed gill epithelial tissues infected with intracellular microcolonies (IMCs) of bacteria resemblingRickettsia-like organisms (RLOs), often with bacteria released in vascular spaces. Large colonies were associated with cellular and tissue disruption of the gills. Ultrastructural examination confirmed the intracellular location of these organisms in affected epithelial cells. The 16S rRNA gene sequences of the putative IMCs obtained from infected king scallop gill samples, collected from both mortality events, were identical and had a 99.4% identity to 16S rRNA gene sequences obtained from “CandidatusEndonucleobacter bathymodioli” and 95% withEndozoicomonasspecies.In situhybridization assays using 16S rRNA gene probes confirmed the presence of the sequenced IMC gene in the gill tissues. Additional DNA sequences of the bacterium were obtained using high-throughput (Illumina) sequencing, and bioinformatic analysis identified over 1,000 genes with high similarity to protein sequences fromEndozoicomonasspp. (ranging from 77 to 87% identity). Specific PCR assays were developed and applied to screen for the presence of IMC 16S rRNA gene sequences in king scallop gill tissues collected at the Lyme Bay MPA during 2015 and 2016. There was 100% prevalence of the IMCs in these gill tissues, and the 16S rRNA gene sequences identified were identical to the sequence found during the previous mortality event.IMPORTANCEMolluscan mass mortalities associated with IMCs have been reported worldwide for many years; however, apart from histological and ultrastructural characterization, characterization of the etiological agents is limited. In the present work, we provide detailed molecular characterization of anEndozoicomonas-like organism (ELO) associated with an important commercial scallop species.


2014 ◽  
Vol 105 (6) ◽  
pp. 1033-1048 ◽  
Author(s):  
Sebastian Gnat ◽  
Magdalena Wójcik ◽  
Sylwia Wdowiak-Wróbel ◽  
Michał Kalita ◽  
Aneta Ptaszyńska ◽  
...  

2008 ◽  
Vol 74 (21) ◽  
pp. 6709-6719 ◽  
Author(s):  
Annette R. Rowe ◽  
Brendan J. Lazar ◽  
Robert M. Morris ◽  
Ruth E. Richardson

ABSTRACT This study sought to characterize bacterial and archaeal populations in a perchloroethene- and butyrate-fed enrichment culture containing hydrogen-consuming “Dehalococcoides ethenogenes” strain 195 and a Methanospirillum hungatei strain. Phylogenetic characterization of this microbial community was done via 16S rRNA gene clone library and gradient gel electrophoresis analyses. Fluorescence in situ hybridization was used to quantify populations of “Dehalococcoides” and Archaea and to examine the colocalization of these two groups within culture bioflocs. A technique for enrichment of planktonic and biofloc-associated biomass was developed and used to assess differences in population distribution and gene expression patterns following provision of substrate. On a per-milliliter-of-culture basis, most D. ethenogenes genes (the hydrogenase gene hupL; the highly expressed gene for an oxidoreductase of unknown function, fdhA; the RNA polymerase subunit gene rpoB; and the 16S rRNA gene) showed no statistical difference in expression between planktonic and biofloc enrichments at either time point studied (1 to 2 and 6 h postfeeding). Normalization of transcripts to ribosome (16S rRNA) levels supported that planktonic and biofloc-associated D. ethenogenes had similar gene expression profiles, with one notable exception; planktonic D. ethenogenes showed higher expression of tceA relative to biofloc-associated cells at 6 h postfeeding. These trends were compared to those for the hydrogen-consuming methanogen in the culture, M. hungatei. The vast majority of M. hungatei cells, ribosomes (16S rRNA), and transcripts of the hydrogenase gene mvrD and the housekeeping gene rpoE were observed in the biofloc enrichments. This suggests that, unlike the comparable activity of D. ethenogenes from both enrichments, planktonic M. hungatei is responsible for only a small fraction of the hydrogenotrophic methanogenesis in this culture.


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