scholarly journals Novelty and Uniqueness Patterns of Rare Members of the Soil Biosphere

2008 ◽  
Vol 74 (17) ◽  
pp. 5422-5428 ◽  
Author(s):  
Mostafa S. Elshahed ◽  
Noha H. Youssef ◽  
Anne M. Spain ◽  
Cody Sheik ◽  
Fares Z. Najar ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
Bacterial Species ◽  
Rrna Gene ◽  
Tall Grass ◽  
Data Set ◽  
Bacterial Phyla ◽  
Rare Biosphere ◽  
Soil Bacterial ◽  
Close Relatives ◽  
Taxonomic Groups

ABSTRACT Soil bacterial communities typically exhibit a distribution pattern in which most bacterial species are present in low abundance. Due to the relatively small size of most culture-independent sequencing surveys, a detailed phylogenetic analysis of rare members of the community is lacking. To gain access to the rarely sampled soil biosphere, we analyzed a data set of 13,001 near-full-length 16S rRNA gene clones derived from an undisturbed tall grass prairie soil in central Oklahoma. Rare members of the soil bacterial community (empirically defined at two different abundance cutoffs) represented 18.1 to 37.1% of the total number of clones in the data set and were, on average, less similar to their closest relatives in public databases when compared to more abundant members of the community. Detailed phylogenetic analyses indicated that members of the soil rare biosphere either belonged to novel bacterial lineages (members of five novel bacterial phyla identified in the data set, as well as members of multiple novel lineages within previously described phyla or candidate phyla), to lineages that are prevalent in other environments but rarely encountered in soil, or were close relatives to more abundant taxa in the data set. While a fraction of the rare community was closely related to more abundant taxonomic groups in the data set, a significant portion of the rare biosphere represented evolutionarily distinct lineages at various taxonomic cutoffs. We reason that these novelty and uniqueness patterns provide clues regarding the origins and potential ecological roles of members of the soil's rare biosphere.

Evaluation of a new fluorimetric DNA–DNA hybridization method

2011 ◽  
Vol 57 (3) ◽  
pp. 250-255 ◽  
Author(s):  
Jennifer Loveland-Curtze ◽  
Vanya I. Miteva ◽  
Jean E. Brenchley
Keyword(s):  
Dna Hybridization ◽  
Bacterial Species ◽  
Sybr Green ◽  
Sybr Green I ◽  
Rrna Gene ◽  
A New Technique ◽  
Thermal Cycler ◽  
Close Relatives ◽  
Taxonomic Groups ◽  
Species Descriptions

Standardized procedures must be followed when characterizing, officially describing, and validly naming novel bacteria. For species descriptions, DNA–DNA hybridization still is needed for whole-genome comparisons between close relatives, but many established hybridization methods have drawbacks, such as requiring labeled or large amounts of DNA. We evaluated a new technique based on the spectrophotometric method in which renaturation rates are used for calculating the degree of binding, which estimates relatedness. In this new approach, DNA is denatured and reassociated in a real-time PCR thermal cycler and the process monitored fluorimetrically using SYBR Green I dye that selectively binds to double-stranded DNA. We investigated the effects of different parameters on the renaturation rates, such as the quantities of DNA and SYBR Green I used. Then using this technique, we calculated the percent binding for pairs of selected bacterial species representing different taxonomic groups and compared our results with published values. We demonstrated that the SYBR Green I method is useful for describing new species and as a screening tool to quickly identify the relatedness of uncharacterized isolates with similar 16S rRNA gene sequences.

scholarly journals Nanopore-Sequencing Characterization of the Gut Microbiota of Melolontha melolontha Larvae: Contribution to Protection against Entomopathogenic Nematodes?

Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 396
Author(s):  
Ewa Sajnaga ◽  
Marcin Skowronek ◽  
Agnieszka Kalwasińska ◽  
Waldemar Kazimierczak ◽  
Karolina Ferenc ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Entomopathogenic Nematodes ◽  
Bacterial Species ◽  
Antagonistic Activity ◽  
Rrna Gene ◽  
Nanopore Sequencing ◽  
Bacterial Phyla ◽  
Melolontha Melolontha

This study focused on the potential relationships between midgut microbiota of the common cockchafer Melolontha melolontha larvae and their resistance to entomopathogenic nematodes (EPN) infection. We investigated the bacterial community associated with control and unsusceptible EPN-exposed insects through nanopore sequencing of the 16S rRNA gene. Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes were the most abundant bacterial phyla within the complex and variable midgut microbiota of the wild M. melolontha larvae. The core microbiota was found to include 82 genera, which accounted for 3.4% of the total number of identified genera. The EPN-resistant larvae differed significantly from the control ones in the abundance of many genera belonging to the Actinomycetales, Rhizobiales, and Clostridiales orders. Additionally, the analysis of the microbiome networks revealed different sets of keystone midgut bacterial genera between these two groups of insects, indicating differences in the mutual interactions between bacteria. Finally, we detected Xenorhabdus and Photorhabdus as gut residents and various bacterial species exhibiting antagonistic activity against these entomopathogens. This study paves the way to further research aimed at unravelling the role of the host gut microbiota on the output of EPN infection, which may contribute to enhancement of the efficiency of nematodes used in eco-friendly pest management.

scholarly journals Enterobacter arachidis sp. nov., a plant-growth-promoting diazotrophic bacterium isolated from rhizosphere soil of groundnut

2010 ◽  
Vol 60 (7) ◽  
pp. 1559-1564 ◽  
Author(s):  
Munusamy Madhaiyan ◽  
Selvaraj Poonguzhali ◽  
Jung-Sook Lee ◽  
Venkatakrishnan Sivaraj Saravanan ◽  
Keun-Chul Lee ◽  
...  
Keyword(s):  
Sequence Analysis ◽  
Gene Sequence ◽  
Rhizosphere Soil ◽  
Phylogenetic Analyses ◽  
Rrna Gene ◽  
Hybridization Data ◽  
Gene Sequence Analysis ◽  
Plant Growth Promoting ◽  
Taxonomic Approach ◽  
Close Relatives

A methylotrophic nitrogen-fixing bacterial strain, Ah-143T, isolated from the rhizosphere soil of field-grown groundnut was analysed by a polyphasic taxonomic approach. Comparative 16S rRNA gene sequence analysis combined with rpoB gene sequence analysis allocated strain Ah-143T to the family Enterobacteriaceae, with Enterobacter radicincitans and Enterobacter cowanii as the closest relatives. The strain is Gram-stain-negative, non-spore-forming, aerobic and motile, having straight rod-shaped cells with a DNA G+C content of approximately 53.2 mol%. The strain utilizes methanol as a carbon source and the mxaF gene was closely related to the mxaF gene of members of the genus Methylobacterium. The fatty acid profile consisted of C16 : 0, C17 : 0 cyclo, C18 : 1 ω7c, summed feature 2 (iso-C16 : 1 I and/or C14 : 0 3-OH) and summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1 ω7c) as the major components. DNA–DNA relatedness of strain Ah-143T with its close relatives was less than 20 %. On the basis of the phylogenetic analyses, DNA–DNA hybridization data, and unique physiological and biochemical characteristics, it is proposed that the strain represents a novel species of the genus Enterobacter and should be named Enterobacter arachidis sp. nov. The type strain is Ah-143T (=NCIMB 14469T =KCTC 22375T).

scholarly journals Novel High-Rank Phylogenetic Lineages within a Sulfur Spring (Zodletone Spring, Oklahoma), Revealed Using a Combined Pyrosequencing-Sanger Approach

2012 ◽  
Vol 78 (8) ◽  
pp. 2677-2688 ◽  
Author(s):  
Noha Youssef ◽  
Brandi L. Steidley ◽  
Mostafa S. Elshahed
Keyword(s):  
High Throughput ◽  
Accurate Determination ◽  
Full Length ◽  
Read Length ◽  
Rrna Gene ◽  
Data Set ◽  
Content Type ◽  
Rare Biosphere ◽  
Phylogenetic Affiliation ◽  
Phylogenetic Lineages

ABSTRACTThe utilization of high-throughput sequencing technologies in 16S rRNA gene-based diversity surveys has indicated that within most ecosystems, a significant fraction of the community could not be assigned to known microbial phyla. Accurate determination of the phylogenetic affiliation of such sequences is difficult due to the short-read-length output of currently available high-throughput technologies. This fraction could harbor multiple novel phylogenetic lineages that have so far escaped detection. Here we describe our efforts in accurate assessment of the novelty and phylogenetic affiliation of selected unclassified lineages within a pyrosequencing data set generated from source sediments of Zodletone Spring, a sulfide- and sulfur-rich spring in southwestern Oklahoma. Lineage-specific forward primers were designed for 78 putatively novel lineages identified within the pyrosequencing data set, and representative nearly full-length small-subunit (SSU) rRNA gene sequences were obtained by pairing those primers with reverse universal bacterial primers. Of the 78 lineages tested, amplifiable products were obtained for 52, 32 of which had at least one nearly full-length sequence that was representative of the lineage targeted. Analysis of phylogenetic affiliation of the obtained Sanger sequences identified 5 novel candidate phyla and 10 novel candidate classes (withinFibrobacteres,Planctomycetes, and candidate phyla BRC1, GN12, TM6, TM7, LD1, WS2, and GN06) in the data set, in addition to multiple novel orders and families. The discovery of multiple novel phyla within a pilot study of a single ecosystem clearly shows the potential of the approach in identifying novel diversities within the rare biosphere.

scholarly journals Natural Product Biosynthetic Gene Diversity in Geographically Distinct Soil Microbiomes

2012 ◽  
Vol 78 (10) ◽  
pp. 3744-3752 ◽  
Author(s):  
Boojala Vijay B. Reddy ◽  
Dimitris Kallifidas ◽  
Jeffrey H. Kim ◽  
Zachary Charlop-Powers ◽  
Zhiyang Feng ◽  
...  
Keyword(s):  
Species Diversity ◽  
Natural Product ◽  
Gene Sequence ◽  
Bacterial Species ◽  
Gene Clusters ◽  
Rrna Gene ◽  
Type I ◽  
Adenylation Domain ◽  
Biosynthetic Gene ◽  
Bacterial Phyla

ABSTRACTThe number of bacterial species estimated to exist on Earth has increased dramatically in recent years. This newly recognized species diversity has raised the possibility that bacterial natural product biosynthetic diversity has also been significantly underestimated by previous culture-based studies. Here, we compare 454-pyrosequenced nonribosomal peptide adenylation domain, type I polyketide ketosynthase domain, and type II polyketide ketosynthase alpha gene fragments amplified from cosmid libraries constructed using DNA isolated from three different arid soils. While 16S rRNA gene sequence analysis indicates these cloned metagenomes contain DNA from similar distributions of major bacterial phyla, we found that they contain almost completely distinct collections of secondary metabolite biosynthetic gene sequences. When grouped at 85% identity, only 1.5% of the adenylation domain, 1.2% of the ketosynthase, and 9.3% of the ketosynthase alpha sequence clusters contained sequences from all three metagenomes. Although there is unlikely to be a simple correlation between biosynthetic gene sequence diversity and the diversity of metabolites encoded by the gene clusters in which these genes reside, our analysis further suggests that sequences in one soil metagenome are so distantly related to sequences in another metagenome that they are, in many cases, likely to arise from functionally distinct gene clusters. The marked differences observed among collections of biosynthetic genes found in even ecologically similar environments suggest that prokaryotic natural product biosynthesis diversity is, like bacterial species diversity, potentially much larger than appreciated from culture-based studies.

scholarly journals Teredinibacter waterburyi sp. nov., a marine, cellulolytic endosymbiotic bacterium isolated from the gills of the wood-boring mollusc Bankia setacea (Bivalvia: Teredinidae) and emended description of the genus Teredinibacter

2020 ◽  
Vol 70 (4) ◽  
pp. 2388-2394 ◽  
Author(s):  
Marvin A. Altamia ◽  
J. Reuben Shipway ◽  
David Stein ◽  
Meghan A. Betcher ◽  
Jennifer M. Fung ◽  
...  
Keyword(s):  
Type Species ◽  
Phylogenetic Analyses ◽  
Bacterial Species ◽  
Sole Source ◽  
Rrna Gene ◽  
Protein Coding ◽  
Content Type ◽  
Link Type ◽  
Emended Description ◽  
Wood Boring

A cellulolytic, aerobic, gammaproteobacterium, designated strain Bs02T, was isolated from the gills of a marine wood-boring mollusc, Bankia setacea (Bivalvia: Teredinidae). The cells are Gram-stain-negative, slightly curved motile rods (2–5×0.4–0.6 µm) that bear a single polar flagellum and are capable of heterotrophic growth in a simple mineral medium supplemented with cellulose as a sole source of carbon and energy. Cellulose, carboxymethylcellulose, xylan, cellobiose and a variety of sugars also support growth. Strain Bs02T requires combined nitrogen for growth. Temperature, pH and salinity optima (range) for growth were 20 °C (range, 10–30 °C), 8.0 (pH 6.5–8.5) and 0.5 M NaCl (range, 0.0–0.8 M), respectively when grown on 0.5 % (w/v) galactose. Strain Bs02T does not require magnesium and calcium ion concentrations reflecting the proportions found in seawater. The genome size is approximately 4.03 Mbp and the DNA G+C content of the genome is 47.8 mol%. Phylogenetic analyses based on 16S rRNA gene sequences, and on conserved protein-coding sequences, show that strain Bs02T forms a well-supported clade with Teredinibacter turnerae . Average nucleotide identity and percentage of conserved proteins differentiate strain Bs02T from Teredinibacter turnerae at threshold values exceeding those proposed to distinguish bacterial species but not genera. These results indicate that strain Bs02T represents a novel species in the previously monotypic genus Teredinibacter for which the name Teredinibacter waterburyi sp. nov. is proposed. The strain has been deposited under accession numbers ATCC TSD-120T and KCTC 62963T.

scholarly journals Characterization of vaginal microbial communities in adult healthy women using cultivation-independent methods

Microbiology ◽  
2004 ◽  
Vol 150 (8) ◽  
pp. 2565-2573 ◽  
Author(s):  
Xia Zhou ◽  
Stephen J. Bent ◽  
Maria G. Schneider ◽  
Catherine C. Davis ◽  
Mohammed R. Islam ◽  
...  
Keyword(s):  
Microbial Community ◽  
16S Rrna ◽  
Dna Sequences ◽  
Phylogenetic Analyses ◽  
Bacterial Species ◽  
Pcr Amplification ◽  
Single Species ◽  
Rrna Gene ◽  
Caucasian Women ◽  
Tract Infections

The normal microbial flora of the vagina plays an important role in preventing genital and urinary tract infections in women. Thus an accurate understanding of the composition and ecology of the ecosystem is important to understanding the aetiology of these diseases. Common wisdom is that lactobacilli dominate the normal vaginal microflora of post-pubertal women. However, this conclusion is based on methods that require cultivation of microbial populations; an approach that is known to yield a biased and incomplete assessment of microbial community structure. In this study cultivation-independent methods were used to analyse samples collected from the mid-vagina of five normal healthy Caucasian women between the ages of 28 and 44. Total microbial community DNA was isolated following resuspension of microbial cells from vaginal swabs. To identify the constituent numerically dominant populations in each community 16S rRNA gene libraries were prepared following PCR amplification using the 8f and 926r primers. From each library, the DNA sequences of approximately 200 16S rRNA clones were determined and subjected to phylogenetic analyses. The diversity and kinds of organisms that comprise the vaginal microbial community varied among women. Species of Lactobacillus appeared to dominate the communities in four of the five women. However, the community of one woman was dominated by Atopobium sp., whereas a second woman had appreciable numbers of Megasphaera sp., Atopobium sp. and Leptotrichia sp., none of which have previously been shown to be common members of the vaginal ecosystem. Of the women whose communities were dominated by lactobacilli, there were two distinct clusters, each of which consisted of a single species. One class consisted of two women with genetically divergent clones that were related to Lactobacillus crispatus, whereas the second group of two women had clones of Lactobacillus iners that were highly related to a single phylotype. These surprising results suggest that culture-independent methods can provide new insights into the diversity of bacterial species found in the human vagina, and this information could prove to be pivotal in understanding risk factors for various infectious diseases.

scholarly journals Nocturnal Production of Endospores in Natural Populations of Epulopiscium-Like Surgeonfish Symbionts

2005 ◽  
Vol 187 (21) ◽  
pp. 7460-7470 ◽  
Author(s):  
Joseph F. Flint ◽  
Dan Drzymalski ◽  
W. Linn Montgomery ◽  
Gordon Southam ◽  
Esther R. Angert
Keyword(s):  
Intestinal Tract ◽  
Dipicolinic Acid ◽  
Phylogenetic Analyses ◽  
Natural Populations ◽  
Rrna Gene ◽  
Gram Positive Bacteria ◽  
Close Relationship ◽  
Close Relatives ◽  
In Situ Hybridizations

ABSTRACT Prior studies have described a morphologically diverse group of intestinal microorganisms associated with surgeonfish. Despite their diversity of form, 16S rRNA gene surveys and fluorescent in situ hybridizations indicate that these bacteria are low-G+C gram-positive bacteria related to Epulopiscium spp. Many of these bacteria exhibit an unusual mode of reproduction, developing multiple offspring intracellularly. Previous reports have suggested that some Epulopiscium-like symbionts produce dormant or phase-bright intracellular offspring. Close relatives of Epulopiscium, such as Metabacterium polyspora and Clostridium lentocellum, are endospore-forming bacteria, which raises the possibility that the phase-bright offspring are endospores. Structural evidence and the presence of dipicolinic acid demonstrate that phase-bright offspring of Epulopiscium-like bacteria are true endospores. In addition, endospores are formed as part of the normal daily life cycle of these bacteria. In the populations studied, mature endospores were seen only at night and the majority of cells in a given population produced one or two endospores per mother cell. Phylogenetic analyses confirmed the close relationship between the endospore-forming surgeonfish symbionts characterized here and previously described Epulopiscium spp. The broad distribution of endospore formation among the Epulopiscium phylogenetic group raises the possibility that sporulation is a characteristic of the group. We speculate that spore formation in Epulopiscium-like symbionts may be important for dispersal and may also enhance survival in the changing conditions of the fish intestinal tract.

scholarly journals Genomics of the Uncultivated, Periodontitis-Associated BacteriumTannerellasp. BU045 (Oral Taxon 808)

mSystems ◽  
2018 ◽  
Vol 3 (3) ◽  
Author(s):  
Clifford J. Beall ◽  
Alisha G. Campbell ◽  
Ann L. Griffen ◽  
Mircea Podar ◽  
Eugene J. Leys
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Chronic Periodontitis ◽  
Bacterial Species ◽  
The United States ◽  
Oral Microbiome ◽  
Rrna Gene ◽  
Bacterial Cells ◽  
Data Set ◽  
Content Type

ABSTRACTDespite decades of research into the human oral microbiome, many species remain uncultivated. The technique of single-cell whole-genome amplification and sequencing provides a means of deriving genome sequences for species that can be informative on biological function and suggest pathways to cultivation.Tannerella forsythiahas long been known to be highly associated with chronic periodontitis and to cause periodontitis-like symptoms in experimental animals, andTannerellasp. BU045 (human oral taxon 808) is an uncultivated relative of this organism. In this work, we extend our previous sequencing of theTannerellasp. BU063 (human oral taxon 286) genome by sequencing amplified genomes from 11 cells ofTannerellasp. BU045, including 3 genomes that are at least 90% complete.Tannerellasp. BU045 is more closely related toTannerellasp. BU063 than toT. forsythiaby gene content and average nucleotide identity. However, two independent data sets of association with periodontitis, one based on 16S rRNA gene abundance and the other based on gene expression in a metatranscriptomic data set, show thatTannerellasp. BU045 is more highly associated with disease thanTannerellasp. BU063. Comparative genomics shows genes and functions that are shared or unique to the different species, which may direct further research of the pathogenesis of chronic periodontitis.IMPORTANCEPeriodontitis (gum disease) affects 47% of adults over 30 in the United States (P. I. Eke, B. A. Dye, L. Wei, G. O. Thornton-Evans, R. J. Genco, et al., J Dent Res 91:914–920, 2012), and it cost between $39 and $396 billion worldwide in 2015 (A. J. Righolt, M. Jevdjevic, W. Marcenes, and S. Listl, J Dent Res, 17 January 2018, https://doi.org/10.1177/0022034517750572). Many bacteria associated with the disease are known only by the DNA sequence of their 16S rRNA gene. In this publication, amplification and sequencing of DNA from single bacterial cells are used to obtain nearly complete genomes ofTannerellasp. BU045, a species of bacteria that is more prevalent in patients with periodontitis than in healthy patients. Comparing the complete genome of this bacterium to genomes of related bacterial species will help to better understand periodontitis and may help to grow this organism in pure culture, which would allow a better understanding of its role in the mouth.

scholarly journals Identifying prognostic pairwise relationships among bacterial species in microbiome studies

2021 ◽  
Vol 17 (11) ◽  
pp. e1009501
Author(s):  
Sean M. Devlin ◽  
Axel Martin ◽  
Irina Ostrovnaya
Keyword(s):  
Bacterial Species ◽  
Human Microbiome ◽  
16S Rrna Gene Sequencing ◽  
R Package ◽  
Major Influence ◽  
Rrna Gene ◽  
Data Set ◽  
Cancer Data ◽  
Selection Framework ◽  
Rrna Gene Sequencing

In recent literature, the human microbiome has been shown to have a major influence on human health. To investigate this impact, scientists study the composition and abundance of bacterial species, commonly using 16S rRNA gene sequencing, among patients with and without a disease or condition. Methods for such investigations to date have focused on the association between individual bacterium and an outcome, and higher-order pairwise relationships or interactions among bacteria are often avoided due to the substantial increase in dimension and the potential for spurious correlations. However, overlooking such relationships ignores the environment of the microbiome, where there is dynamic cooperation and competition among bacteria. We present a method for identifying and ranking pairs of bacteria that have a differential dichotomized relationship across outcomes. Our approach, implemented in an R package PairSeek, uses the stability selection framework with data-driven dichotomized forms of the pairwise relationships. We illustrate the properties of the proposed method using a published oral cancer data set and a simulation study.

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