scholarly journals Methanogen Diversity Evidenced by Molecular Characterization of Methyl Coenzyme M Reductase A (mcrA) Genes in Hydrothermal Sediments of the Guaymas Basin

2005 ◽  
Vol 71 (8) ◽  
pp. 4592-4601 ◽  
Author(s):  
Ashita Dhillon ◽  
Mark Lever ◽  
Karen G. Lloyd ◽  
Daniel B. Albert ◽  
Mitchell L. Sogin ◽  
...  
Keyword(s):  
16S Rrna ◽  
Gulf Of California ◽  
Pcr Amplification ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Coenzyme M ◽  
Clone Libraries ◽  
Guaymas Basin ◽  
Methanogen Community ◽  
Methyl Coenzyme M Reductase

ABSTRACT The methanogenic community in hydrothermally active sediments of Guaymas Basin (Gulf of California, Mexico) was analyzed by PCR amplification, cloning, and sequencing of methyl coenzyme M reductase (mcrA) and 16S rRNA genes. Members of the Methanomicrobiales and Methanosarcinales dominated the mcrA and 16S rRNA clone libraries from the upper 15 cm of the sediments. Within the H2/CO2- and formate-utilizing family Methanomicrobiales, two mcrA and 16S rRNA lineages were closely affiliated with cultured species of the genera Methanoculleus and Methanocorpusculum. The most frequently recovered mcrA PCR amplicons within the Methanomicrobiales did not branch with any cultured genera. Within the nutritionally versatile family Methanosarcinales, one 16S rRNA amplicon and most of the mcrA PCR amplicons were affiliated with the obligately acetate utilizing species Methanosaeta concilii. The mcrA clone libraries also included phylotypes related to the methyl-disproportionating genus Methanococcoides. However, two mcrA and two 16S rRNA lineages within the Methanosarcinales were unrelated to any cultured genus. Overall, the clone libraries indicate a diversified methanogen community that uses H2/CO2, formate, acetate, and methylated substrates. Phylogenetic affiliations of mcrA and 16S rRNA clones with thermophilic and nonthermophilic cultured isolates indicate a mixed mesophilic and thermophilic methanogen community in the surficial Guaymas sediments.

scholarly journals Molecular Characterization of Sulfate-Reducing Bacteria in the Guaymas Basin

2003 ◽  
Vol 69 (5) ◽  
pp. 2765-2772 ◽  
Author(s):  
Ashita Dhillon ◽  
Andreas Teske ◽  
Jesse Dillon ◽  
David A. Stahl ◽  
Mitchell L. Sogin
Keyword(s):  
16S Rrna ◽  
Gulf Of California ◽  
Sulfate Reducing Bacteria ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Terrestrial Organic Matter ◽  
Guaymas Basin ◽  
Sulfate Reducers ◽  
Sulfate Reducing ◽  
Reducing Bacteria

ABSTRACT The Guaymas Basin (Gulf of California) is a hydrothermal vent site where thermal alteration of deposited planktonic and terrestrial organic matter forms petroliferous material which supports diverse sulfate-reducing bacteria. We explored the phylogenetic and functional diversity of the sulfate-reducing bacteria by characterizing PCR-amplified dissimilatory sulfite reductase (dsrAB) and 16S rRNA genes from the upper 4 cm of the Guaymas sediment. The dsrAB sequences revealed that there was a major clade closely related to the acetate-oxidizing delta-proteobacterial genus Desulfobacter and a clade of novel, deeply branching dsr sequences related to environmental dsr sequences from marine sediments in Aarhus Bay and Kysing Fjord (Denmark). Other dsr clones were affiliated with gram-positive thermophilic sulfate reducers (genus Desulfotomaculum) and the delta-proteobacterial species Desulforhabdus amnigena and Thermodesulforhabdus norvegica. Phylogenetic analysis of 16S rRNAs from the same environmental samples resulted in identification of four clones affiliated with Desulfobacterium niacini, a member of the acetate-oxidizing, nutritionally versatile genus Desulfobacterium, and one clone related to Desulfobacula toluolica and Desulfotignum balticum. Other bacterial 16S rRNA bacterial phylotypes were represented by non-sulfate reducers and uncultured lineages with unknown physiology, like OP9, OP8, as well as a group with no clear affiliation. In summary, analyses of both 16S rRNA and dsrAB clone libraries resulted in identification of members of the Desulfobacteriales in the Guaymas sediments. In addition, the dsrAB sequencing approach revealed a novel group of sulfate-reducing prokaryotes that could not be identified by 16S rRNA sequencing.

scholarly journals Evaluation of 16S, map1 and pCS20 probes for detection of Cowdria and Ehrlichia species

1999 ◽  
Vol 122 (2) ◽  
pp. 323-328 ◽  
Author(s):  
M. T. E. P. ALLSOPP ◽  
C. M. HATTINGH ◽  
S. W. VOGEL ◽  
B. A. ALLSOPP
Keyword(s):  
16S Rrna ◽  
Ribosomal Rna ◽  
Pcr Amplification ◽  
16S Ribosomal Rna ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Amblyomma Hebraeum ◽  
Ribosomal Rna Gene ◽  
Group Iii ◽  
16S Ribosomal Rna Gene

A panel of 16S ribosomal RNA gene probes has been developed for the study of the epidemiology of heartwater; five of these detect different cowdria genotypes, one detects five distinct genotypes; one detects any Group III Ehrlichia species other than Cowdria and one detects any Group II Ehrlichia species. These probes have been used on PCR-amplified rickettsial 16S rRNA genes from over 200 Amblyomma hebraeum ticks. Control ticks were laboratory-reared and either uninfected or fed on sheep experimentally infected with different cowdria isolates, field ticks were collected from animals in heartwater-endemic areas. All tick-derived DNA samples were also examined by PCR amplification and probing for two other cowdria genes (map1 and pCS20) which have previously been used for heartwater epidemiology. This paper describes the first direct comparison of all currently available DNA probes for heartwater-associated organisms.

scholarly journals Oligonucleotide Microarray for 16S rRNA Gene-Based Detection of All Recognized Lineages of Sulfate-Reducing Prokaryotes in the Environment

2002 ◽  
Vol 68 (10) ◽  
pp. 5064-5081 ◽  
Author(s):  
Alexander Loy ◽  
Angelika Lehner ◽  
Natuschka Lee ◽  
Justyna Adamczyk ◽  
Harald Meier ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Pcr Amplification ◽  
Oligonucleotide Microarray ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Clinical Samples ◽  
Rrna Gene ◽  
Sulfate Reducing ◽  
Specific Pcr

ABSTRACT For cultivation-independent detection of sulfate-reducing prokaryotes (SRPs) an oligonucleotide microarray consisting of 132 16S rRNA gene-targeted oligonucleotide probes (18-mers) having hierarchical and parallel (identical) specificity for the detection of all known lineages of sulfate-reducing prokaryotes (SRP-PhyloChip) was designed and subsequently evaluated with 41 suitable pure cultures of SRPs. The applicability of SRP-PhyloChip for diversity screening of SRPs in environmental and clinical samples was tested by using samples from periodontal tooth pockets and from the chemocline of a hypersaline cyanobacterial mat from Solar Lake (Sinai, Egypt). Consistent with previous studies, SRP-PhyloChip indicated the occurrence of Desulfomicrobium spp. in the tooth pockets and the presence of Desulfonema- and Desulfomonile-like SRPs (together with other SRPs) in the chemocline of the mat. The SRP-PhyloChip results were confirmed by several DNA microarray-independent techniques, including specific PCR amplification, cloning, and sequencing of SRP 16S rRNA genes and the genes encoding the dissimilatory (bi)sulfite reductase (dsrAB).

scholarly journals Prey Range Characterization, Ribotyping, and Diversity of Soil and Rhizosphere Bdellovibriospp. Isolated on Phytopathogenic Bacteria

2000 ◽  
Vol 66 (6) ◽  
pp. 2365-2371 ◽  
Author(s):  
E. Jurkevitch ◽  
D. Minz ◽  
Barak Ramati ◽  
Gili Barel
Keyword(s):  
16S Rrna ◽  
Common Bean ◽  
Pcr Amplification ◽  
Erwinia Carotovora ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Range Analysis ◽  
Pcr Product ◽  
Utilization Patterns ◽  
Range Characterization

ABSTRACT Thirty new Bdellovibrio strains were isolated from an agricultural soil and from the rhizosphere of plants grown in that soil. Using a combined molecular and culture-based approach, we found that the soil bdellovibrios included subpopulations of organisms that differed from rhizosphere bdellovibrios. Thirteen soil and seven common bean rhizosphere Bdellovibrio strains were isolated when Pseudomonas corrugata was used as prey; seven and two soil strains were isolated when Erwinia carotovora subsp.carotovora and Agrobacterium tumefaciens, respectively, were used as prey; and one tomato rhizosphere strain was isolated when A. tumefaciens was used as prey. In soil and in the rhizosphere, depending on the prey cells used, the concentrations of bdellovibrios were between 3 × 102 to 6 × 103 and 2.8 × 102 to 2.3 × 104 PFU g−1. A prey range analysis of five soil and rhizosphereBdellovibrio isolates performed with 22 substrate species, most of which were plant-pathogenic and plant growth-enhancing bacteria, revealed unique utilization patterns and differences between closely related prey cells. An approximately 830-bp fragment of the 16S rRNA genes of all of theBdellovibrio strains used was obtained by PCR amplification by using a Bdellovibrio-specific primer combination. Soil and common bean rhizosphere strains produced two and one restriction patterns for this PCR product, respectively. The 16S rRNA genes of three soil isolates and three root-associated isolates were sequenced. One soil isolate belonged to theBdellovibrio stolpii-Bdellovibrio starrii clade, while all of the other isolates clustered withBdellovibrio bacteriovorus and formed two distantly related, heterogeneous groups.

scholarly journals Phylogenetic Comparison of the Methanogenic Communities from an Acidic, Oligotrophic Fen and an Anaerobic Digester Treating Municipal Wastewater Sludge

2008 ◽  
Vol 74 (21) ◽  
pp. 6663-6671 ◽  
Author(s):  
Lisa M. Steinberg ◽  
John M. Regan
Keyword(s):  
16S Rrna ◽  
Municipal Wastewater ◽  
Anaerobic Digester ◽  
Wastewater Sludge ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Large Temperature ◽  
Clone Libraries ◽  
Average Sequence ◽  
Sequence Similarities

ABSTRACT Methanogens play a critical role in the decomposition of organics under anaerobic conditions. The methanogenic consortia in saturated wetland soils are often subjected to large temperature fluctuations and acidic conditions, imposing a selective pressure for psychro- and acidotolerant community members; however, methanogenic communities in engineered digesters are frequently maintained within a narrow range of mesophilic and circumneutral conditions to retain system stability. To investigate the hypothesis that these two disparate environments have distinct methanogenic communities, the methanogens in an oligotrophic acidic fen and a mesophilic anaerobic digester treating municipal wastewater sludge were characterized by creating clone libraries for the 16S rRNA and methyl coenzyme M reductase alpha subunit (mcrA) genes. A quantitative framework was developed to assess the differences between these two communities by calculating the average sequence similarity for 16S rRNA genes and mcrA within a genus and family using sequences of isolated and characterized methanogens within the approved methanogen taxonomy. The average sequence similarities for 16S rRNA genes within a genus and family were 96.0 and 93.5%, respectively, and the average sequence similarities for mcrA within a genus and family were 88.9 and 79%, respectively. The clone libraries of the bog and digester environments showed no overlap at the species level and almost no overlap at the family level. Both libraries were dominated by clones related to uncultured methanogen groups within the Methanomicrobiales, although members of the Methanosarcinales and Methanobacteriales were also found in both libraries. Diversity indices for the 16S rRNA gene library of the bog and both mcrA libraries were similar, but these indices indicated much lower diversity in the 16S digester library than in the other three libraries.

scholarly journals Genetic diversity of 16S rRNA and mcrA genes from methanogenic archaeas

2020 ◽  
Vol 42 ◽  
pp. e49877
Author(s):  
Keyla Vitoria Marques Xavier ◽  
Eden Silva e Souza ◽  
Erick de Aquino Santos ◽  
Michely Correia Diniz
Keyword(s):  
Genetic Diversity ◽  
16S Rrna ◽  
Descriptive Analysis ◽  
Methanogenic Archaea ◽  
Ribosomal Gene ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Terrestrial Environments ◽  
Methyl Coenzyme M Reductase ◽  
Potential Use

Methanogenic archaeas are found in aquatic and terrestrial environments and are fundamental in the conversion of organic matter into methane, a gas that has a potential use as renewable source of energy, which is also considered as one of the main agents of the greenhouse effect. The vast majority of microbial genomes can be identified by a conservative molecular marker, the 16S ribosomal gene. However, the mcrA gene have been using in studies of methanogenic archaea diversity as an alternative marker, highly conserved and present only in methanogens. This gene allows the expression of the enzyme Methyl-coenzyme M reductase, the main agent in converting by-products of anaerobic digestion into methane. In this context, we aimed to study the genetic diversity of mcrA and 16S rRNA genes sequences available in databases. The nucleotide sequences were selected from the NCBI. The heterozygosity and molecular diversity indexes were calculated using the Arlequin 3.5 software, with plots generated by package R v3.0. The diversity and heterozygosity indices for both genes may have been influenced by the number and size of the sequences. Descriptive analysis of genetic diversity generated by sequences deposited in databases allowed a detailed study of these molecules. It is known that the organisms in a population are genetically distinct, and that, despite having similarities in their gene composition, the differences are essential for their adaptation to different environments.

scholarly journals Intestinal TM7 bacterial phylogenies in active inflammatory bowel disease

2008 ◽  
Vol 57 (12) ◽  
pp. 1569-1576 ◽  
Author(s):  
Tanja Kuehbacher ◽  
Ateequr Rehman ◽  
Patricia Lepage ◽  
Stephan Hellmig ◽  
Ulrich R. Fölsch ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
16S Rrna ◽  
Molecular Techniques ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Base Substitution ◽  
Clone Libraries ◽  
Bowel Diseases ◽  
Inflammatory Bowel ◽  
Almost All

TM7 is a recently described subgroup of Gram-positive uncultivable bacteria originally found in natural environmental habitats. An association of the TM7 bacterial division with the inflammatory pathogenesis of periodontitis has been previously shown. This study investigated TM7 phylogenies in patients with inflammatory bowel diseases (IBDs). The mucosal microbiota of patients with active Crohn's disease (CD; n=42) and ulcerative colitis (UC; n=31) was compared with that of controls (n=33). TM7 consortia were examined using molecular techniques based on 16S rRNA genes, including clone libraries, sequencing and in situ hybridization. TM7 molecular signatures could be cloned from mucosal samples of both IBD patients and controls, but the composition of the clone libraries differed significantly. Taxonomic analysis of the sequences revealed a higher diversity of TM7 phylotypes in CD (23 different phylotypes) than in UC (10) and non-IBD controls (12). All clone libraries showed a high number of novel sequences (21 for controls, 34 for CD and 29 for UC). A highly atypical base substitution for bacterial 16S rRNA genes associated with antibiotic resistance was detected in almost all sequences from CD (97.3 %) and UC (100 %) patients compared to only 65.1 % in the controls. TM7 bacteria might play an important role in IBD similar to that previously described in oral inflammation. The alterations of TM7 bacteria and the genetically determined antibiotic resistance of TM7 species in IBD could be a relevant part of a more general alteration of bacterial microbiota in IBD as recently found, e.g. as a promoter of inflammation at early stages of disease.

scholarly journals Selective and Sensitive Method for PCR Amplification of Escherichia coli 16S rRNA Genes in Soil

2000 ◽  
Vol 66 (2) ◽  
pp. 844-849 ◽  
Author(s):  
G. Sabat ◽  
P. Rose ◽  
W. J. Hickey ◽  
J. M. Harkin
Keyword(s):  
Escherichia Coli ◽  
16S Rrna ◽  
Pcr Amplification ◽  
Pcr Primers ◽  
Enteric Bacteria ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Selective Amplification ◽  
E Coli

ABSTRACT A set of PCR primers targeting 16S rRNA gene sequences was designed, and PCR parameters were optimized to develop a robust and reliable protocol for selective amplification of Escherichia coli 16S rRNA genes. The method was capable of discriminatingE. coli from other enteric bacteria, including its closest relative, Shigella. Selective amplification of E. coli occurred only when the annealing temperature in the PCR was elevated to 72°C, which is 10°C higher than the optimum for the primers. Sensitivity was retained by modifying the length of steps in the PCR, by increasing the number of cycles, and most importantly by optimizing the MgCl2 concentration. The PCR protocol developed can be completed in less then 2 h and, by using Southern hybridization, has a detection limit of ca. 10 genomic equivalents per reaction. The method was demonstrated to be effective for detectingE. coli DNA in heterogeneous DNA samples, such as those extracted from soil.

Sign in / Sign up

Export Citation Format

Share Document