scholarly journals Archaeal Diversity and the Prevalence of Crenarchaeota in Salt Marsh Sediments

2009 ◽  
Vol 75 (12) ◽  
pp. 4211-4215 ◽  
Author(s):  
Katelyn A. Nelson ◽  
Nicole S. Moin ◽  
Anne E. Bernhard
Keyword(s):  
Salt Marsh ◽  
16S Rrna ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Archaeal Diversity ◽  
Group I ◽  
Marsh Sediments ◽  
Salt Marsh Sediments ◽  
Rrna Sequences ◽  
16S Rrna Sequences

ABSTRACT Crenarchaeal 16S rRNA sequences constituted over 70% of the archaeal clones recovered from three salt marsh sites dominated by different grasses. Group I.1a Crenarchaeota dominated at two sites, while group I.3b Crenarchaeota sequences were most abundant at a third site. Abundances of 16S rRNA genes related to “Candidatus Nitrosopumilus maritimus” differed by site and sampling date.

scholarly journals Distribution and Diversity of Archaeal and Bacterial Ammonia Oxidizers in Salt Marsh Sediments

2009 ◽  
Vol 75 (23) ◽  
pp. 7461-7468 ◽  
Author(s):  
Nicole S. Moin ◽  
Katelyn A. Nelson ◽  
Alexander Bush ◽  
Anne E. Bernhard
Keyword(s):  
Salt Marsh ◽  
16S Rrna ◽  
New England ◽  
Water Column ◽  
Salt Marshes ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Group I ◽  
Marsh Sediments ◽  
Salt Marsh Sediments

ABSTRACT Diversity and abundance of ammonia-oxidizing Betaproteobacteria (β-AOB) and archaea (AOA) were investigated in a New England salt marsh at sites dominated by short or tall Spartina alterniflora (SAS and SAT sites, respectively) or Spartina patens (SP site). AOA amoA gene richness was higher than β-AOB amoA richness at SAT and SP, but AOA and β-AOB richness were similar at SAS. β-AOB amoA clone libraries were composed exclusively of Nitrosospira-like amoA genes. AOA amoA genes at SAT and SP were equally distributed between the water column/sediment and soil/sediment clades, while AOA amoA sequences at SAS were primarily affiliated with the water column/sediment clade. At all three site types, AOA were always more abundant than β-AOB based on quantitative PCR of amoA genes. At some sites, we detected 109 AOA amoA gene copies g of sediment−1. Ratios of AOA to β-AOB varied over 2 orders of magnitude among sites and sampling dates. Nevertheless, abundances of AOA and β-AOB amoA genes were highly correlated. Abundance of 16S rRNA genes affiliated with Nitrosopumilus maritimus, Crenarchaeota group I.1b, and pSL12 were positively correlated with AOA amoA abundance, but ratios of amoA to 16S rRNA genes varied among sites. We also observed a significant effect of pH on AOA abundance and a significant salinity effect on both AOA and β-ΑΟΒ abundance. Our results expand the distribution of AOA to salt marshes, and the high numbers of AOA at some sites suggest that salt marsh sediments serve as an important habitat for AOA.

scholarly journals Divergence and Redundancy of 16S rRNA Sequences in Genomes with Multiple rrn Operons

2004 ◽  
Vol 186 (9) ◽  
pp. 2629-2635 ◽  
Author(s):  
Silvia G. Acinas ◽  
Luisa A. Marcelino ◽  
Vanja Klepac-Ceraj ◽  
Martin F. Polz
Keyword(s):  
16S Rrna ◽  
Thermophilic Bacteria ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Bacterial Genomes ◽  
16S Rrna Sequence ◽  
Thermoanaerobacter Tengcongensis ◽  
Copy Numbers ◽  
Rrna Sequences ◽  
16S Rrna Sequences

ABSTRACT The level of sequence heterogeneity among rrn operons within genomes determines the accuracy of diversity estimation by 16S rRNA-based methods. Furthermore, the occurrence of widespread horizontal gene transfer (HGT) between distantly related rrn operons casts doubt on reconstructions of phylogenetic relationships. For this study, patterns of distribution of rrn copy numbers, interoperonic divergence, and redundancy of 16S rRNA sequences were evaluated. Bacterial genomes display up to 15 operons and operon numbers up to 7 are commonly found, but ∼40% of the organisms analyzed have either one or two operons. Among the Archaea, a single operon appears to dominate and the highest number of operons is five. About 40% of sequences among 380 operons in 76 bacterial genomes with multiple operons were identical to at least one other 16S rRNA sequence in the same genome, and in 38% of the genomes all 16S rRNAs were invariant. For Archaea, the number of identical operons was only 25%, but only five genomes with 21 operons are currently available. These considerations suggest an upper bound of roughly threefold overestimation of bacterial diversity resulting from cloning and sequencing of 16S rRNA genes from the environment; however, the inclusion of genomes with a single rrn operon may lower this correction factor to ∼2.5. Divergence among operons appears to be small overall for both Bacteria and Archaea, with the vast majority of 16S rRNA sequences showing <1% nucleotide differences. Only five genomes with operons with a higher level of nucleotide divergence were detected, and Thermoanaerobacter tengcongensis exhibited the highest level of divergence (11.6%) noted to date. Overall, four of the five extreme cases of operon differences occurred among thermophilic bacteria, suggesting a much higher incidence of HGT in these bacteria than in other groups.

scholarly journals Relationships of Bradyrhizobia from the LegumesApios americana and Desmodium glutinosum

1999 ◽  
Vol 65 (11) ◽  
pp. 4914-4920 ◽  
Author(s):  
Matthew A. Parker
Keyword(s):  
16S Rrna ◽  
Root Nodule ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
23S Rrna ◽  
Enzyme Electrophoresis ◽  
Nodule Bacteria ◽  
Root Nodule Bacteria ◽  
Rrna Sequences ◽  
16S Rrna Sequences

ABSTRACT Multilocus enzyme electrophoresis, partial 23S rRNA sequences, and nearly full-length 16S rRNA sequences all indicated high genetic similarity among root-nodule bacteria associated with Apios americana, Desmodium glutinosum, andAmphicarpaea bracteata, three common herbaceous legumes whose native geographic ranges in eastern North America overlap extensively. A total of 19 distinct multilocus genotypes (electrophoretic types [ETs]) were found among the 35 A. americana and 33 D. glutinosum isolates analyzed. Twelve of these ETs (representing 78% of all isolates) were either identical to ETs previously observed in A. bracteatapopulations, or differed at only one locus. Within both 23S and 16S rRNA genes, several isolates from A. americana and D. glutinosum were either identical to A. bracteataisolates or showed only single nucleotide differences. Growth rates and nitrogenase activities of A. bracteata plants inoculated with isolates from D. glutinosum were equivalent to levels found with native A. bracteata bacterial isolates, but none of the three A. americana isolates tested had high symbiotic effectiveness on A. bracteata. Phylogenetic analysis of both 23S and 16S rRNA sequences indicated that bothA. americana and D. glutinosum harbored rare bacterial genotypes similar to Bradyrhizobium japonicumUSDA 110. However, the predominant root nodule bacteria on both legumes were closely related to Bradyrhizobium elkanii.

scholarly journals Effect of Freezing on PCR Amplification of 16S rRNA Genes from Microbes Associated with Black Band Disease of Corals

2009 ◽  
Vol 75 (8) ◽  
pp. 2581-2584 ◽  
Author(s):  
Raju Sekar ◽  
Longin T. Kaczmarsky ◽  
Laurie L. Richardson
Keyword(s):  
16S Rrna ◽  
Pcr Amplification ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Black Band Disease ◽  
Black Band ◽  
Sulfur Oxidizing ◽  
Polymicrobial Disease ◽  
Rrna Sequences ◽  
16S Rrna Sequences

ABSTRACT Molecular analysis of black band disease of corals revealed that samples frozen immediately after collection yielded more proteobacterial 16S rRNA sequences, while unfrozen samples produced more cyanobacterial and sulfur-oxidizing bacterial sequences. These results suggest the need to use multiple approaches for preparation of samples to characterize this complex polymicrobial disease.

scholarly journals Effect of Temperature and Light on Growth of and Photosynthesis by Synechococcus Isolates Typical of Those Predominating in the Octopus Spring Microbial Mat Community of Yellowstone National Park

2006 ◽  
Vol 72 (1) ◽  
pp. 544-550 ◽  
Author(s):  
Jessica P. Allewalt ◽  
Mary M. Bateson ◽  
Niels Peter Revsbech ◽  
Kimberly Slack ◽  
David M. Ward
Keyword(s):  
16S Rrna ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Effect Of Temperature ◽  
Ecological Niches ◽  
Genotype Distribution ◽  
Unicellular Cyanobacterium ◽  
Temperature Ranges ◽  
Rrna Sequences ◽  
16S Rrna Sequences

ABSTRACT Previous molecular analysis of the Octopus Spring cyanobacterial mat revealed numerous genetically distinct 16S rRNA sequences from predominant Synechococcus populations distantly related to the readily cultivated unicellular cyanobacterium Synechococcus lividus. Patterns in genotype distribution relative to temperature and light conditions suggested that the organisms contributing these 16S rRNA sequences may fill distinct ecological niches. To test this hypothesis, Synechococcus isolates were cultivated using a dilution and filtration approach and then shown to be genetically relevant to natural mat populations by comparisons of similarities of 16S rRNA genes and 16S-23S internal transcribed spacer (ITS) regions. Most isolates were identical or nearly identical at both loci to predominant mat genotypes; others showed 1- to 2-nucleotide differences at the 16S rRNA locus and even greater difference in ITS sequences. Isolates with predominant mat genotypes had distinct temperature ranges and optima for growth that were consistent with their distributions in the mat. Isolates with genotypes not previously detected or known to be predominant in the mat exhibited temperature ranges and optima that were not representative of predominant mat populations and also grew more slowly. Temperature effects on photosynthesis did not reflect temperature relations for growth. However, the isolate with the highest temperature optimum and upper limit was capable of performing photosynthesis at a higher temperature than other isolates. Growth rate and photosynthetic responses provided evidence for light acclimation but evidence of, at best, only subtle light adaptation.

scholarly journals Potential Interactions of Particle-Associated Anammox Bacteria with Bacterial and Archaeal Partners in the Namibian Upwelling System

2007 ◽  
Vol 73 (14) ◽  
pp. 4648-4657 ◽  
Author(s):  
Dagmar Woebken ◽  
Bernhard M. Fuchs ◽  
Marcel M. M. Kuypers ◽  
Rudolf Amann
Keyword(s):  
16S Rrna ◽  
Free Water ◽  
Water Phase ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Anammox Bacteria ◽  
Upwelling System ◽  
Group I ◽  
Anammox Activity

ABSTRACT Recent studies have shown that the anaerobic oxidation of ammonium by anammox bacteria plays an important role in catalyzing the loss of nitrogen from marine oxygen minimum zones (OMZ). However, in situ oxygen concentrations of up to 25 μM and ammonium concentrations close to or below the detection limit in the layer of anammox activity are hard to reconcile with the current knowledge of the physiology of anammox bacteria. We therefore investigated samples from the Namibian OMZ by comparative 16S rRNA gene analysis and fluorescence in situ hybridization. Our results showed that “Candidatus Scalindua” spp., the typical marine anammox bacteria, colonized microscopic particles that were likely the remains of either macroscopic marine snow particles or resuspended particles. These particles were slightly but significantly (P < 0.01) enriched in Gammaproteobacteria (11.8% ± 5.0%) compared to the free-water phase (8.1% ± 1.8%). No preference for the attachment to particles could be observed for members of the Alphaproteobacteria and Bacteroidetes, which were abundant (12 to 17%) in both habitats. The alphaproteobacterial SAR11 clade, the Euryarchaeota, and group I Crenarchaeota, were all significantly depleted in particles compared to their presence in the free-water phase (16.5% ± 3.5% versus 2.6% ± 1.7%, 2.7% ± 1.9% versus <1%, and 14.9% ± 4.6% versus 2.2% ± 1.8%, respectively, all P < 0.001). Sequence analysis of the crenarchaeotal 16S rRNA genes showed a 99% sequence identity to the nitrifying “Nitrosopumilus maritimus.” Even though we could not observe conspicuous consortium-like structures of anammox bacteria with particle-enriched bacterioplankton groups, we hypothesize that members of Gammaproteobacteria, Alphaproteobacteria, and Bacteroidetes play a critical role in extending the anammox reaction to nutrient-depleted suboxic water layers in the Namibian upwelling system by creating anoxic, nutrient-enriched microniches.

scholarly journals Different Active Microbial Communities in Two Contrasted Subantarctic Fjords

2021 ◽  
Vol 12 ◽  
Author(s):  
Claudia Maturana-Martínez ◽  
Camila Fernández ◽  
Humberto E. González ◽  
Pierre E. Galand
Keyword(s):  
Climate Change ◽  
Microbial Community ◽  
16S Rrna ◽  
Microbial Communities ◽  
Standing Stock ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Biogeochemical Processes ◽  
Biogeographic Patterns ◽  
Group I

Microorganisms play a crucial role in biogeochemical processes affecting the primary production and biogeochemical cycles of the ocean. In subpolar areas, the increment of the water temperature induced by climate change could lead to changes in the structure and activity of planktonic microbial communities. To understand how the structure of the microbial community in Chilean Patagonian fjords could be affected by climate change, we analyzed the composition of the prokaryotic community (bacteria-archaea) in two fjords (Pia and Yendegaia) with contrasting morphological and hydrological features. We targeted both the standing stock (16S rRNA genes) and the active fraction (16S rRNA transcripts) of the microbial communities during two consecutive austral winters. Our results showed that in both fjords, the active community had higher diversity and stronger biogeographic patterns when compared to the standing stock. Members of the Alpha-, Gamma-, and Deltaproteobacteria followed by archaea from the Marine Group I (Thaumarchaeota) dominated the active communities in both fjords. However, in Pia fjord, which has a marine-terminating glacier, the composition of the microbial community was directly influenced by the freshwater discharges from the adjacent glacier, and indirectly by a possible upwelling phenomenon that could bring deep sea bacteria such as SAR202 to the surface layer. In turn, in the Yendegaia, which has a land-terminating glacier, microbial communities were more similar to the ones described in oceanic waters. Furthermore, in Yendegaia fjord, inter-annual differences in the taxonomic composition and diversity of the microbial community were observed. In conclusion, Yendegaia fjord, without glacier calving, represents a fjord type that will likely be more common under future climate scenarios. Our results showing distinct Yendegaia communities, with for example more potential nitrogen-fixing microorganisms (Planctomycetes), indicate that as a result of climate change, changing planktonic communities could potentially impact biogeochemical processes and nutrient sources in subantarctic fjords.

scholarly journals Whole-Cell versus Total RNA Extraction for Analysis of Microbial Community Structure with 16S rRNA-Targeted Oligonucleotide Probes in Salt Marsh Sediments

2000 ◽  
Vol 66 (7) ◽  
pp. 3037-3043 ◽  
Author(s):  
Marc E. Frischer ◽  
Jean M. Danforth ◽  
Michele A. Newton Healy ◽  
F. Michael Saunders
Keyword(s):  
Salt Marsh ◽  
16S Rrna ◽  
Microbial Communities ◽  
Rna Extraction ◽  
Oligonucleotide Probes ◽  
Whole Cell ◽  
Sulfate Reducing ◽  
Marsh Sediments ◽  
Salt Marsh Sediments ◽  
Reducing Bacteria

ABSTRACT rRNA-targeted oligonucleotide probes have become powerful tools for describing microbial communities, but their use in sediments remains difficult. Here we describe a simple technique involving homogenization, detergents, and dispersants that allows the quantitative extraction of cells from formalin-preserved salt marsh sediments. Resulting cell extracts are amenable to membrane blotting and hybridization protocols. Using this procedure, the efficiency of cell extraction was high (95.7% � 3.7% [mean � standard deviation]) relative to direct DAPI (4′,6′-diamidino-2-phenylindole) epifluorescence cell counts for a variety of salt marsh sediments. To test the hypothesis that cells were extracted without phylogenetic bias, the relative abundance (depth distribution) of five major divisions of the gram-negative mesophilic sulfate-reducing delta proteobacteria were determined in sediments maintained in a tidal mesocosm system. A suite of six 16S rRNA-targeted oligonucleotide probes were utilized. The apparent structure of sulfate-reducing bacteria communities determined from whole-cell and RNA extracts were consistent with each other (r 2 = 0.60), indicating that the whole-cell extraction and RNA extraction hybridization approaches for describing sediment microbial communities are equally robust. However, the variability associated with both methods was high and appeared to be a result of the natural heterogeneity of sediment microbial communities and methodological artifacts. The relative distribution of sulfate-reducing bacteria was similar to that observed in natural marsh systems, providing preliminary evidence that the mesocosm systems accurately simulate native marsh systems.

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