scholarly journals Gene orders in the upstream of 16S rRNA genes divide genera of the family Halobacteriaceae into two groups

2012 ◽  
Vol 62 (1) ◽  
pp. 188-195 ◽  
Author(s):  
Hiroaki Minegishi ◽  
Masahiro Kamekura ◽  
Tomomi Kitajima-Ihara ◽  
Kaoru Nakasone ◽  
Akinobu Echigo ◽  
...  

In many prokaryotic species, 16S rRNA genes are present in multiple copies, and their sequences in general do not differ significantly owing to concerted evolution. At the time of writing, the genus Haloarcula of the family Halobacteriaceae comprises nine species with validly published names, all of which possess two to four highly heterogeneous 16S rRNA genes. Existence of multiple heterogeneous 16S rRNA genes makes it difficult to reconstruct a biological phylogenetic tree using their sequence data. If the orthologous gene is able to be discriminated from paralogous genes, a tree reconstructed from orthologous genes will reflect a simple biological phylogenetic relationship. At present, however, we have no means to distinguish the orthologous rRNA operon from paralogous ones in the members of the family Halobacteriaceae. In this study, we found that the dihydroorotate oxidase gene, pyrD, was present in the immediate upstream of one 16S rRNA gene in each of ten strains of the family Halobacteriaceae whose genome sequences have been determined, and the direction of the pyrD gene was opposite to that of the 16S rRNA genes. In two other strains whose genome sequences have been determined, the pyrD gene was present in far separated positions. We designed PCR primer sets to amplify DNA fragments encompassing a region from the conserved region of the pyrD gene to a conserved region of the tRNA-Ala gene or the 23S rRNA gene to determine the 16S rRNA gene sequences preceded by the pyrD gene, and to see if the pyrD gene is conserved in the immediate upstream of rRNA operon(s) in the type strains of the type species of 28 genera of the family Halobacteriaceae. Seventeen type strains, including the ten strains mentioned above, gave amplified DNA fragments of approximately 4000 bp, while eleven type strains, including the two strains mentioned above, did not give any PCR products. These eleven strains are members of the Clade I haloarchaea, originally defined by Walsh et al. (2004) and expanded by Minegishi et al. (2010). Analysis of contig sequences of three strains belonging to the Clade I haloarchaea also revealed the absence of the pyrD gene in the immediate upstream of any 16S rRNA genes. It may be scientifically sound to hypothesize that during the evolution of members of the family Halobacteriaceae, a pyrD gene transposition event happened in one group and this was followed by subsequent speciation processes in each group, yielding species/genera of the Clade I group and ‘the rest’ of the present family Halobacteriaceae.

2015 ◽  
Vol 41 (1) ◽  
pp. 51-58
Author(s):  
Mohammad Shamimul Alam ◽  
Hawa Jahan ◽  
Rowshan Ara Begum ◽  
Reza M Shahjahan

Heteropneustesfossilis, Clariasbatrachus and C. gariepinus are three major catfishes ofecological and economic importance. Identification of these fish species becomes aproblem when the usual external morphological features of the fish are lost or removed,such as in canned fish. Also, newly hatched fish larva is often difficult to identify. PCRsequencingprovides accurate alternative means of identification of individuals at specieslevel. So, 16S rRNA genes of three locally collected catfishes were sequenced after PCRamplification and compared with the same gene sequences available from othergeographical regions. Multiple sequence alignment of the 16S rRNA gene fragments ofthe catfish species has revealed polymorphic sites which can be used to differentiate thesethree species from one another and will provide valuable insight in choosing appropriaterestriction enzymes for PCR-RFLP based identification in future. Asiat. Soc. Bangladesh, Sci. 41(1): 51-58, June 2015


2005 ◽  
Vol 71 (10) ◽  
pp. 6308-6318 ◽  
Author(s):  
Helen A. Vrionis ◽  
Robert T. Anderson ◽  
Irene Ortiz-Bernad ◽  
Kathleen R. O'Neill ◽  
Charles T. Resch ◽  
...  

ABSTRACT The geochemistry and microbiology of a uranium-contaminated subsurface environment that had undergone two seasons of acetate addition to stimulate microbial U(VI) reduction was examined. There were distinct horizontal and vertical geochemical gradients that could be attributed in large part to the manner in which acetate was distributed in the aquifer, with more reduction of Fe(III) and sulfate occurring at greater depths and closer to the point of acetate injection. Clone libraries of 16S rRNA genes derived from sediments and groundwater indicated an enrichment of sulfate-reducing bacteria in the order Desulfobacterales in sediment and groundwater samples. These samples were collected nearest the injection gallery where microbially reducible Fe(III) oxides were highly depleted, groundwater sulfate concentrations were low, and increases in acid volatile sulfide were observed in the sediment. Further down-gradient, metal-reducing conditions were present as indicated by intermediate Fe(II)/Fe(total) ratios, lower acid volatile sulfide values, and increased abundance of 16S rRNA gene sequences belonging to the dissimilatory Fe(III)- and U(VI)-reducing family Geobacteraceae. Maximal Fe(III) and U(VI) reduction correlated with maximal recovery of Geobacteraceae 16S rRNA gene sequences in both groundwater and sediment; however, the sites at which these maxima occurred were spatially separated within the aquifer. The substantial microbial and geochemical heterogeneity at this site demonstrates that attempts should be made to deliver acetate in a more uniform manner and that closely spaced sampling intervals, horizontally and vertically, in both sediment and groundwater are necessary in order to obtain a more in-depth understanding of microbial processes and the relative contribution of attached and planktonic populations to in situ uranium bioremediation.


2003 ◽  
Vol 69 (9) ◽  
pp. 5512-5518 ◽  
Author(s):  
Brett J. Baker ◽  
Philip Hugenholtz ◽  
Scott C. Dawson ◽  
Jillian F. Banfield

ABSTRACT During a molecular phylogenetic survey of extremely acidic (pH < 1), metal-rich acid mine drainage habitats in the Richmond Mine at Iron Mountain, Calif., we detected 16S rRNA gene sequences of a novel bacterial group belonging to the order Rickettsiales in the Alphaproteobacteria. The closest known relatives of this group (92% 16S rRNA gene sequence identity) are endosymbionts of the protist Acanthamoeba. Oligonucleotide 16S rRNA probes were designed and used to observe members of this group within acidophilic protists. To improve visualization of eukaryotic populations in the acid mine drainage samples, broad-specificity probes for eukaryotes were redesigned and combined to highlight this component of the acid mine drainage community. Approximately 4% of protists in the acid mine drainage samples contained endosymbionts. Measurements of internal pH of the protists showed that their cytosol is close to neutral, indicating that the endosymbionts may be neutrophilic. The endosymbionts had a conserved 273-nucleotide intervening sequence (IVS) in variable region V1 of their 16S rRNA genes. The IVS does not match any sequence in current databases, but the predicted secondary structure forms well-defined stem loops. IVSs are uncommon in rRNA genes and appear to be confined to bacteria living in close association with eukaryotes. Based on the phylogenetic novelty of the endosymbiont sequences and initial culture-independent characterization, we propose the name “Candidatus Captivus acidiprotistae.” To our knowledge, this is the first report of an endosymbiotic relationship in an extremely acidic habitat.


2007 ◽  
Vol 57 (9) ◽  
pp. 2143-2146 ◽  
Author(s):  
Dong-Shan An ◽  
Wan-Taek Im ◽  
Sung-Taik Lee ◽  
Min-Ho Yoon

A novel bacterial strain designated Gsoil 616T was isolated from a soil sample of a ginseng field in Pocheon province (South Korea) and was characterized taxonomically by using a polyphasic approach. The isolate was Gram-positive, strictly aerobic, non-motile, non-spore-forming and rod- or coccoid-shaped. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate belongs to the genus Nocardioides in the family Nocardioidaceae but was clearly separated from established species of this genus. The 16S rRNA gene sequence similarities between strain Gsoil 616T and the type strains of Nocardioides species with validly published names ranged from 91.8 to 96.1 %. The G+C content of the genomic DNA was 73 mol%. Phenotypic and chemotaxonomic data [major menaquinone MK-8(H4) and major fatty acid iso-C16 : 0] supported the affiliation of strain Gsoil 616T to the genus Nocardioides. However, the results of physiological and biochemical tests allowed phenotypic differentiation of the isolate from other Nocardioides species. Therefore, strain Gsoil 616T represented a novel species within the genus Nocardioides, for which the name Nocardioides panacihumi sp. nov. is proposed. The type strain is Gsoil 616T (=KCTC 19187T =DSM 18660T).


2009 ◽  
Vol 75 (12) ◽  
pp. 4139-4148 ◽  
Author(s):  
James P. Davis ◽  
Noha H. Youssef ◽  
Mostafa S. Elshahed

ABSTRACT We used a combination of 16S rRNA gene clone library surveys, quantitative PCR (qPCR) analysis, and fluorescent in situ hybridization to investigate the diversity, abundance, and distribution of members of candidate division SR1 in multiple habitats. Using SR1-specific 16S rRNA gene primers, we identified multiple novel SR1 lineages in four different anaerobic environments: sediments from Zodletone Spring, a sulfide- and sulfur-rich spring in southwestern Oklahoma; inner layers of microbial mats obtained from Sperm Pool, a high-temperature, low-pH pool (55°C, pH 2.5) in Yellowstone National Park; fresh bovine ruminal contents; and anaerobic freshwater pond sediments (Duck Pond) in Norman, Oklahoma. qPCR analysis indicated that SR1 members constitute a small fraction (<0.01%) of the microbial communities in Duck Pond and ruminal samples but constitute a significant fraction (11.6 and 48.7%) of the total number of bacterial 16S rRNA genes in Zodletone Spring and the inner layers of Sperm Pool microbial mat samples, respectively. By using SR1-specific fluorescent probes, filamentous cells were identified as the sole SR1 morphotype in all environments examined, with the exception of Sperm Pool, where a second bacillus morphotype was also identified. Using a full-cycle 16S rRNA approach, we show that each of these two morphotypes corresponds to a specific phylogenetic lineage identified in the Sperm Pool clone library. This work greatly expands the intralineage phylogenetic diversity within candidate division SR1 and provides valuable quantification and visualization tools that could be used for investigating the ecological roles, dynamics, and genomics of this as-yet-uncultured bacterial phylum.


Author(s):  
Sooyeon Park ◽  
Jung-Sook Lee ◽  
Wonyong Kim ◽  
Jung-Hoon Yoon

Two Gram-stain-negative and non-flagellated bacteria, YSTF-M3T and YSTF-M6T, were isolated from a tidal flat from Yellow Sea, Republic of Korea, and subjected to a polyphasic taxonomic study. Neighbour-joining phylogenetic tree of 16S rRNA gene sequences showed that strains YSTF-M3T and YSTF-M6T belong to the genera Kordia and Olleya of the family Flavobacteriaceae , respectively. The 16S rRNA gene sequence similarities between strain YSTF-M3T and the type strains of Kordia species and between strain YSTF-M6T and the type strains of Olleya species were 94.1–98.4 and 97.3–98.3 %, respectively. The ANI and dDDH values between genomic sequences of strain YSTF-M3T and the type strains of five Kordia species and between those of strain YSTF-M6T and the type strains of three Olleya species were in ranges of 77.0–83.2 and 20.7–27.1 % and 79.4–81.5 and 22.3–23.9 %, respectively. The DNA G+C contents of strain YSTF-M3T and YSTF-M6T from genomic sequences were 34.1 and 31.1 %, respectively. Both strains contained MK-6 as predominant menaquinone and phosphatidylethanolamine as only major phospholipid identified. Differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strains YSTF-M3T and YSTF-M6T are separated from recognized species of the genera Kordia and Olleya , respectively. On the basis of the data presented, strains YSTF-M3T (=KACC 21639T=NBRC 114499T) and YSTF-M6T (=KACC 21640T=NBRC 114500T) are considered to represent novel species of the genera Kordia and Olleya , respectively, for which the names Kordia aestuariivivens sp. nov. and Olleya sediminilitoris sp. nov. are proposed.


2004 ◽  
Vol 54 (4) ◽  
pp. 1349-1353 ◽  
Author(s):  
Chuji Hiruki ◽  
Keri Wang

Clover proliferation phytoplasma (CPR) is designated as the reference strain for the CP phylogenetic group or subclade, on the basis of molecular analyses of genomic DNA, the 16S rRNA gene and the 16S–23S spacer region. Other strains related to CPR include alfalfa witches'-broom (AWB), brinjal little leaf (BLL), beet leafhopper-transmitted virescence (BLTV), Illinois elm yellows (ILEY), potato witches'-broom (PWB), potato yellows (PY), tomato big bud in California (TBBc) and phytoplasmas from Fragaria multicipita (FM). Phylogenetic analysis of the 16S rRNA gene sequences of BLL, CPR, FM and ILEY, together with sequences from 16 other phytoplasmas that belong to the ash yellows (AshY), jujube witches'-broom (JWB) and elm yellows (EY) groups that were available in GenBank, produced a tree on which these phytoplasmas clearly clustered as a discrete group. Three subgroups have been classified on the basis of sequence homology and the collective RFLP patterns of amplified 16S rRNA genes. AWB, BLTV, PWB and TBBc are assigned to taxonomic subgroup CP-A, FM belongs to subgroup CP-B and BLL and ILEY are assigned to subgroup CP-C. Genetic heterogeneity between different isolates of AWB, CPR and PWB has been observed from heteroduplex mobility assay analysis of amplified 16S rRNA genes and the 16S–23S spacer region. Two unique signature sequences that can be utilized to distinguish the CP group from others were present. On the basis of unique properties of the DNA from clover proliferation phytoplasma, the name ‘Candidatus Phytoplasma trifolii’ is proposed for the CP group.


2012 ◽  
Vol 62 (Pt_9) ◽  
pp. 2163-2168 ◽  
Author(s):  
Yong-Taek Jung ◽  
Ji-Hoon Kim ◽  
So-Jung Kang ◽  
Tae-Kwang Oh ◽  
Jung-Hoon Yoon

A Gram-staining-negative, non-flagellated, non-gliding and pleomorphic bacterial strain, designated DPG-25T, was isolated from seawater in a seaweed farm in the South Sea in Korea and its taxonomic position was investigated by using a polyphasic approach. Strain DPG-25T grew optimally at 25 °C, at pH 7.0–7.5 and in the presence of 2 % (w/v) NaCl. Flexirubin-type pigments were not produced. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain DPG-25T formed a cluster with the type strains of Actibacter sediminis , Aestuariicola saemankumensis and Lutimonas vermicola . Strain DPG-25T exhibited 16S rRNA gene sequence similarity values of 95.3, 93.1 and 93.6 % to the type strains of Actibacter sediminis , Aestuariicola saemankumensis and L. vermicola , respectively. Strain DPG-25T contained MK-6 as the predominant menaquinone and iso-C15 : 0 and iso-C17 : 0 3-OH as the major fatty acids. The major polar lipids detected in strain DPG-25T were phosphatidylethanolamine and one unidentified lipid. The DNA G+C content was 39.9 mol%. Differential phenotypic properties and the phylogenetic distinctiveness of strain DPG-25T demonstrated that this strain is distinguishable from Actibacter sediminis , Aestuariicola saemankumensis and L. vermicola . On the basis of the data presented here, strain DPG-25T represents a novel species in a novel genus of the family Flavobacteriaceae , for which the name Namhaeicola litoreus gen. nov., sp. nov. is proposed. The type strain of Namhaeicola litoreus is DPG-25T ( = KCTC 23702T  = CCUG 61485T).


PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2492 ◽  
Author(s):  
Catherine M. Burke ◽  
Aaron E. Darling

BackgroundThe bacterial 16S rRNA gene has historically been used in defining bacterial taxonomy and phylogeny. However, there are currently no high-throughput methods to sequence full-length 16S rRNA genes present in a sample with precision.ResultsWe describe a method for sequencing near full-length 16S rRNA gene amplicons using the high throughput Illumina MiSeq platform and test it using DNA from human skin swab samples. Proof of principle of the approach is demonstrated, with the generation of 1,604 sequences greater than 1,300 nt from a single Nano MiSeq run, with accuracy estimated to be 100-fold higher than standard Illumina reads. The reads were chimera filtered using information from a single molecule dual tagging scheme that boosts the signal available for chimera detection.ConclusionsThis method could be scaled up to generate many thousands of sequences per MiSeq run and could be applied to other sequencing platforms. This has great potential for populating databases with high quality, near full-length 16S rRNA gene sequences from under-represented taxa and environments and facilitates analyses of microbial communities at higher resolution.


2017 ◽  
Vol 61 ◽  
pp. 69-84 ◽  
Author(s):  
Ali Naghoni ◽  
Giti Emtiazi ◽  
Mohammad Ali Amoozegar ◽  
Zahra Etemadifar ◽  
Seyed Abolhassan Shahzadeh Fazeli

Repetitive extragenic palindromic elements-polymerase chain reaction (rep-PCR) with 16S ribosomal ribonucleic acid (16S rRNA) genes sequences successfully used for the analysis of microbial community. In this study, the prokaryotic community in Lake Meyghan described by using rep-PCR analysis along with 16S rRNA gene sequencing. The water samples were collected from Lake Meyghan in November 2013. All samples were diluted and cultured on three different media. To estimate the number of prokaryotes per milliliter of the lake we used quantitative real‑time PCR (qPCR). Rep-PCR combination with 16S rRNA gene sequencing was performed to investigate prokaryotes biodiversity in the lake. 305 strains were isolated in this work; 113 isolates for green region, 102 isolates for red region, and 90 isolates for white region. The dendrograms generated 10, 7, and 9 clusters for a 70 % similarity cut-off for green, red, and white regions, respectively. Based on rep-PCR and 16S rRNA gene sequencing, the recovered isolates were dominated by (77.5 %)Halobacteriacaeand many isolates were related to the generaHalorubrum,Haloarcula,Haloterrigena,Natrinema, andHalovivaxin the white region. In the red region more isolated strains (57.5 %) belonged toBacillaceaeand the remaining 42.5 % of isolates belonged to archaea domain,Halorubrum, andHaloarcula. In the green region members ofGammaproteobacteriawere recoverd, this region was dominant withPseudoalteromonas,Salinivibrio, andAliidiomarina.


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