scholarly journals Gut Microbiomes of Freshwater Mussels (Unionidae) Are Taxonomically and Phylogenetically Variable across Years but Remain Functionally Stable

2021 ◽  
Vol 9 (2) ◽  
pp. 411
Author(s):  
Mark McCauley ◽  
Marlène Chiarello ◽  
Carla L. Atkinson ◽  
Colin R. Jackson
Keyword(s):  
16S Rrna ◽  
Temporal Variation ◽  
Gut Microbiome ◽  
Freshwater Mussels ◽  
Ecosystem Functions ◽  
Microbiome Diversity ◽  
Host Development ◽  
Rrna Sequences ◽  
Over Time ◽  
16S Rrna Sequences

Freshwater mussels perform essential ecosystem functions, yet we have no information on how their microbiomes fluctuate over time. In this study, we examined temporal variation in the microbiome of six mussel species (Lampsilis ornata, Obovaria unicolor, Elliptio arca, Fusconaia cerina, Cyclonaias asperata, and Tritogonia verrucosa) sampled from the same river in 2016 and 2019. We examined the taxonomic, phylogenetic, and inferred functional (from 16S rRNA sequences) facets of their microbiome diversity. Significant differences between the two years were identified in five of the six species sampled. However, not all species that exhibited a temporally variable microbiome were functionally distinct across years, indicating functional redundancy within the mussel gut microbiome. Inferred biosynthesis pathways showed temporal variation in pathways involved in degradation, while pathways involved in cellular metabolism were stable. There was no evidence for phylosymbiosis across any facet of microbiome biodiversity. These results indicate that temporal variation is an important factor in the assembly of the gut microbiomes of freshwater mussels and provides further support that the mussel gut microbiome is involved in host development and activity.

scholarly journals Microheterogeneity in 16S Ribosomal DNA-Defined Bacterial Populations from a Stratified Planktonic Environment Is Related to Temporal Changes and to Ecological Adaptations

2002 ◽  
Vol 68 (4) ◽  
pp. 1706-1714 ◽  
Author(s):  
Emilio O. Casamayor ◽  
Carlos Pedrós-Alió ◽  
Gerard Muyzer ◽  
Rudolf Amann
Keyword(s):  
16S Rrna ◽  
Ribosomal Dna ◽  
Dna Sequences ◽  
Temporal Changes ◽  
Epifluorescence Microscopy ◽  
Purple Sulfur Bacterium ◽  
16S Ribosomal Dna ◽  
Rrna Sequences ◽  
Over Time ◽  
16S Rrna Sequences

ABSTRACT Temporal changes of the bacterioplankton from a meromictic lake (Lake Vilar, Banyoles, Spain) were analyzed with four culture-independent techniques: epifluorescence microscopy, PCR-denaturing gradient gel electrophoresis (DGGE) fingerprinting, fluorescence in situ whole-cell hybridization and flow cytometry sorting. Microscopically, blooms of one cyanobacterium (Synechococcus sp.-like), one green sulfur bacterium (Chlorobium phaeobacteroides-like), and one purple sulfur bacterium (Thiocystis minor-like) were observed at different depths and times. DGGE retrieved these populations and, additionally, populations related to the Cytophaga-Flavobacterium-Bacteroides phylum as predominant community members. The analyses of partial 16S ribosomal DNA sequences from the DGGE fingerprints (550 bp analyzed) revealed higher genetic diversity than expected from microscopic observation for most of these groups. Thus, the sequences of two Synechococcus spp. (both had a similarity of 97% to Synechococcus sp. strain PCC6307 in 16S rRNA), two Thiocystis spp. (similarities to Thiocystis minor of 93 and 94%, respectively), and three Cytophaga spp. (similarities to Cytophaga fermentans of 88 and 89% and to Cytophaga sp. of 93%, respectively) were obtained. The two populations of Synechococcus exhibited different pigment compositions and temporal distributions and their 16S rRNA sequences were 97.3% similar. The two Thiocystis populations differed neither in pigment composition nor in morphology, but their 16S rRNA sequences were only 92.3% similar and they also showed different distributions over time. Finally, two of the Cytophaga spp. showed 96.2% similarity between the 16S rRNA sequences, but one of them was found to be mostly attached to particles and only in winter. Thus, the identity of the main populations changed over time, but the function of the microbial guilds was maintained. Our data showed that temporal shifts in the identity of the predominant population is a new explanation for the environmental 16S rRNA microdiversity retrieved from microbial assemblages and support the hypothesis that clusters of closely related 16S rRNA environmental sequences may actually represent numerous closely related, yet ecologically distinct, populations.

scholarly journals Structure, culture, and predicted function of the gut microbiome of the Mormon cricketAnabrus simplex(Orthoptera: Tettigoniidae)

2016 ◽  
Author(s):  
Chad C. Smith ◽  
Robert B. Srygley ◽  
Frank Healy ◽  
Karthikeyan Swaminath ◽  
Ulrich G. Mueller
Keyword(s):  
Lactic Acid ◽  
Community Structure ◽  
Lactic Acid Bacteria ◽  
16S Rrna ◽  
Gut Microbiome ◽  
Gene Content ◽  
Pathogen Defense ◽  
Mormon Cricket ◽  
Rrna Sequences ◽  
16S Rrna Sequences

SUMMARYThe gut microbiome of insects plays an important role in their ecology and evolution, participating in nutrient acquisition, immunity, and behavior. Microbial community structure within the gut is heavily influenced by differences among gut regions in morphology and physiology, which determine the niches available for microbes to colonize.We present a high-resolution analysis of the structure of the gut microbiome in the Mormon cricketAnabrus simplex,an insect known for its periodic outbreaks in the western United States and nutrition-dependent mating system. The Mormon cricket microbiome was dominated by eleven taxa from the Lactobacillaceae, Enterobacteriaceae, and Streptococcaeae. While most of these were represented in all gut regions, there were marked differences in their relative abundance, with lactic-acid bacteria (Lactobacillaceae) more common in the foregut and midgut and enteric (Enterobacteriaceae) bacteria more common in the hindgut.Differences in community structure were driven by variation in the relative prevalence of three groups: aLactobacillusin the foregut,Pediococcuslactic-acid bacteria in the midgut, andPantoea agglomerans, an enteric bacterium, in the hindgut. These taxa have been shown to have beneficial effects on their hosts in insects and other animals by improving nutrition, increasing resistance to pathogens, and modulating social behavior.Using PICRUSt to predict gene content from our 16S rRNA sequences, we found enzymes that participate in carbohydrate metabolism and pathogen defense in other orthopterans. These were predominately represented in the hindgut and midgut, the most important sites for nutrition and pathogen defense.Phylogenetic analysis of 16S rRNA sequences from cultured isolates indicated low levels of divergence from sequences derived from plants and other insects, suggesting that these bacteria are likely to be exchanged between Mormon crickets and the environment.Our study shows strong spatial variation in microbiome community structure, which influences predicted gene content and thus the potential of the microbiome to influence host function.

scholarly journals Correction to: Bacterial community assemblages in classroom floor dust of 50 public schools in a large city: characterization using 16S rRNA sequences and associations with environmental factors

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Ju-Hyeong Park ◽  
Angela R. Lemons ◽  
Jerry Roseman ◽  
Brett J. Green ◽  
Jean M. Cox-Ganser
Keyword(s):  
Public Schools ◽  
Environmental Factors ◽  
Bacterial Community ◽  
16S Rrna ◽  
Large City ◽  
Floor Dust ◽  
Community Assemblages ◽  
Rrna Sequences ◽  
16S Rrna Sequences

An amendment to this paper has been published and can be accessed via the original article.

scholarly journals 16S rRNA sequences reveal uncultured inhabitants of a well-studied thermal community

1990 ◽  
Vol 75 (2-3) ◽  
pp. 105-115 ◽  
Author(s):  
David M. Ward ◽  
Roland Weller ◽  
Mary M. Bateson
Keyword(s):  
16S Rrna ◽  
Rrna Sequences ◽  
16S Rrna Sequences

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 Occurrence of diazotrophic bacteria in Araucaria angustifolia

2007 ◽  
Vol 64 (3) ◽  
pp. 303-304 ◽  
Author(s):  
Rafaela de Fátima Neroni ◽  
Elke Jurandy Bran Nogueira Cardoso
Keyword(s):  
16S Rrna ◽  
Acetylene Reduction ◽  
Araucaria Angustifolia ◽  
Diazotrophic Bacteria ◽  
Araucaria Forest ◽  
Solid Media ◽  
Reduction Assay ◽  
Semi Solid ◽  
Rrna Sequences ◽  
16S Rrna Sequences

Araucaria angustifolia is an environmentally threatened tree and the whole biota of the Araucaria Forest should be investigated with the aim of its preservation. Diazotrophic bacteria are extremely important for the maintenance of ecosystems, but they have never been studied in Araucaria Forests. In this study, diazotrophic bacteria were isolated from Araucaria roots and soil, when grown in semi-specific, semi-solid media. The diazotrophic character of some recovered isolates could be confirmed using the acetylene reduction assay. According to their 16S rRNA sequences, most of these isolates belong to the genus Burkholderia.

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