scholarly journals Development and Application of a Real-Time PCR Approach for Quantification of Uncultured Bacteria in the Central Baltic Sea

2004 ◽  
Vol 70 (8) ◽  
pp. 4971-4979 ◽  
Author(s):  
Matthias Labrenz ◽  
Ingrid Brettar ◽  
Richard Christen ◽  
Sebastien Flavier ◽  
Julia Bötel ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Baltic Sea ◽  
Real Time ◽  
Relative Abundance ◽  
Real Time Pcr ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Uncultured Bacteria

ABSTRACT We have developed a highly sensitive approach to assess the abundance of uncultured bacteria in water samples from the central Baltic Sea by using a noncultured member of the “Epsilonproteobacteria” related to Thiomicrospira denitrificans as an example. Environmental seawater samples and samples enriched for the target taxon provided a unique opportunity to test the approach over a broad range of abundances. The approach is based on a combination of taxon- and domain-specific real-time PCR measurements determining the relative T. denitrificans-like 16S rRNA gene and 16S rRNA abundances, as well as the determination of total cell counts and environmental RNA content. It allowed quantification of T. denitrificans-like 16S rRNA molecules or 16S rRNA genes as well as calculation of the number of ribosomes per T. denitrificans-like cell. Every real-time measurement and its specific primer system were calibrated using environmental nucleic acids obtained from the original habitat for external standardization. These standards, as well as the respective samples to be measured, were prepared from the same DNA or RNA extract. Enrichment samples could be analyzed directly, whereas environmental templates had to be preamplified with general bacterial primers before quantification. Preamplification increased the sensitivity of the assay by more than 4 orders of magnitude. Quantification of enrichments with or without a preamplification step yielded comparable results. T. denitrificans-like 16S rRNA molecules ranged from 7.1 × 103 to 4.4 × 109 copies ml−1 or 0.002 to 49.7% relative abundance. T. denitrificans-like 16S rRNA genes ranged from 9.0 × 101 to 2.2 ×106 copies ml−1 or 0.01 to 49.7% relative abundance. Detection limits of this real-time-PCR approach were 20 16S rRNA molecules or 0.2 16S rRNA gene ml−1. The number of ribosomes per T. denitrificans-like cell was estimated to range from 20 to 200 in seawater and reached up to 2,000 in the enrichments. The results indicate that our real-time PCR approach can be used to determine cellular and relative abundances of uncultured marine bacterial taxa and to provide information about their levels of activity in their natural environment.

scholarly journals Development and Assessment of a Real-Time PCR Assay for Rapid and Sensitive Detection of a Novel Thermotolerant Bacterium, Lactobacillus thermotolerans, in Chicken Feces

2005 ◽  
Vol 71 (8) ◽  
pp. 4214-4219 ◽  
Author(s):  
Abu Sadeque Md Selim ◽  
Piyanuch Boonkumklao ◽  
Teruo Sone ◽  
Apinya Assavanig ◽  
Masaru Wada ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Real Time ◽  
Real Time Pcr ◽  
Pure Culture ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Pcr Assay ◽  
Chicken Feces

ABSTRACT A new real-time PCR assay was successfully developed using a TaqMan fluorescence probe for specific detection and enumeration of a novel bacterium, Lactobacillus thermotolerans, in chicken feces. The specific primers and probe were designed based on the L. thermotolerans 16S rRNA gene sequences, and these sequences were compared to those of all available 16S rRNA genes in the GenBank database. The assay, targeting 16S rRNA gene, was evaluated using DNA from a pure culture of L. thermotolerans, DNA from the closely related bacteria Lactobacillus mucosae DSM 13345T and Lactobacillus fermentum JCM 1173T, and DNA from other lactic acid bacteria in quantitative experiments. Serial dilutions of L. thermotolerans DNA were used as external standards for calibration. The minimum detection limit of this technique was 1.84 × 103 cells/ml of an L. thermotolerans pure culture. The assay was then applied to chicken feces in two different trials. In the first trial, the cell population was 104 cells/g feces on day 4 and 105 cells/g feces on days 11 to 18. However, cell populations of 106 to 107 cells/g feces were detected in the second trial. The total bacterial count, measured by 4′,6-diamidino-2-phenylindole (DAPI) staining, was approximately 1011 cells/g feces. These results suggest that in general, L. thermotolerans is a normal member of the chicken gut microbiota, although it is present at relatively low levels in the feces.

Impact of a probiotic, inulin, or their combination on the piglets’ microbiota at different intestinal locations

2015 ◽  
Vol 6 (4) ◽  
pp. 473-483 ◽  
Author(s):  
V.A. Sattler ◽  
K. Bayer ◽  
G. Schatzmayr ◽  
A.G. Haslberger ◽  
V. Klose
Keyword(s):  
16S Rrna ◽  
Gut Microbiota ◽  
16S Rrna Gene ◽  
Real Time ◽  
Relative Abundance ◽  
Real Time Pcr ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Feed Additives ◽  
Rrna Gene ◽  
16S Rrna Gene Pyrosequencing

Natural feed additives are used to maintain health and to promote performance of pigs without antibiotics. Effects of a probiotic, inulin, and their combination (synbiotic), on the microbial diversity and composition at different intestinal locations were analysed using denaturing gradient gel electrophoresis (DGGE), real-time PCR, and 16S rRNA gene pyrosequencing. Bacterial diversity assessed by DGGE and/or pyrosequencing was increased by inulin in all three gut locations and by the synbiotic in the caecum and colon. In contrast, the probiotic did only affect the microbiota diversity in the ileum. Shifts in the DGGE microbiota profiles of the caecum and colon were detected for the pro- and synbiotic fed animals, whereas inulin profiles were more similar to the ones of the control. 16S rRNA gene pyrosequencing revealed that all three additives could reduce Escherichia species in each gut location, indicating a potential beneficial effect on the gut microbiota. An increase of relative abundance of Clostridiaceae in the large intestine was found in the inulin group and of Enterococcaceae in the ileum of probiotic fed pigs. Furthermore, real-time PCR results showed that the probiotic and synbiotic increased bifidobacterial numbers in the ileum, which was supported by sequencing results. The probiotic and inulin, to different extents, changed the diversity, relative abundance of phylotypes, and community profiles of the porcine microbiota. However, alterations of the bacterial community were not uniformly between gut locations, demonstrating that functionality of feed additives is site specific. Therefore, gut sampling from various locations is crucial when investigations aim to identify the composition of a healthy gut microbiota after its manipulation through feed additives.

scholarly journals Real-Time PCR Screening for 16S rRNA Mutations Associated with Resistance to Tetracycline in Helicobacter pylori

2005 ◽  
Vol 49 (8) ◽  
pp. 3166-3170 ◽  
Author(s):  
Erik Glocker ◽  
Marco Berning ◽  
Monique M. Gerrits ◽  
Johannes G. Kusters ◽  
Manfred Kist
Keyword(s):  
Helicobacter Pylori ◽  
16S Rrna ◽  
Real Time ◽  
Real Time Pcr ◽  
Tetracycline Resistance ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Pcr Screening ◽  
H Pylori

ABSTRACT The effectiveness of recommended first-line therapies for Helicobacter pylori infections is decreasing due to the occurrence of resistance to metronidazole and/or clarithromycin. Quadruple therapies, which include tetracycline and a bismuth salt, are useful alternative regimens. However, resistance to tetracycline, mainly caused by mutations in the 16S rRNA genes (rrnA and rrnB) affecting nucleotides 926 to 928, are already emerging and can impair the efficacies of such second-line regimens. Here, we describe a novel real-time PCR for the detection of 16S rRNA gene mutations associated with tetracycline resistance. Our PCR method was able to distinguish between wild-type strains and resistant strains exhibiting single-, double, or triple-base-pair mutations. The method was applicable both to DNA extracted from pure cultures and to DNA extracted from fresh or frozen H. pylori-infected gastric biopsy samples. We therefore conclude that this real-time PCR is an excellent method for determination of H. pylori tetracycline resistance even when live bacteria are no longer available.

Rapid PCR identification of Prevotella copri in an Australian cohort of pregnant women

2019 ◽  
Vol 11 (3) ◽  
pp. 228-234 ◽  
Author(s):  
Lawrence Gray ◽  
Kyoko Hasebe ◽  
Martin O’Hely ◽  
Anne-Louise Ponsonby ◽  
Peter Vuillermin ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Real Time ◽  
Relative Abundance ◽  
Real Time Pcr ◽  
Cost Effective ◽  
Birth Cohort Study ◽  
Rrna Gene ◽  
Sequencing Data ◽  
Cost Effective Technique

AbstractGut bacteria from the genus Prevotella are found in high abundance in faeces of non-industrialised communities but low abundance in industrialised, Westernised communities. Prevotella copri is one of the principal Prevotella species within the human gut. As it has been associated with developmental health and disease states, we sought to (i) develop a real-time polymerase chain reaction (PCR) to rapidly determine P. copri abundance and (ii) investigate its abundance in a large group of Australian pregnant mothers.The Barwon Infant Study is a pre-birth cohort study (n = 1074). Faecal samples were collected from mothers at 36 weeks gestation. Primers with a probe specific to the V3 region of P. copri 16S rRNA gene were designed and optimised for real-time PCR. Universal 16S rRNA gene primers amplified pan-bacterial DNA in parallel. Relative abundance of P. copri was calculated using a 2-ΔCt method.Relative abundance of P. copri by PCR was observed in 165/605 (27.3%) women. The distribution was distinctly bimodal, defining women with substantial (n = 115/165, 69.7%) versus very low P. copri expression (n = 50/165, 30.3%). In addition, abundance of P. copri by PCR correlated with 16S rRNA gene MiSeq sequencing data (r2 = 0.67, P < 0.0001, n = 61).We have developed a rapid and cost-effective technique for identifying the relative abundance of P. copri using real-time PCR. The expression of P. copri was evident in only a quarter of the mothers, and either at substantial or very low levels. PCR detection of P. copri may facilitate assessment of this species in large, longitudinal studies across multiple populations and in various clinical settings.

scholarly journals Molecular Biological Detection and Quantification of Novel Fibrobacter Populations in Freshwater Lakes

2009 ◽  
Vol 75 (15) ◽  
pp. 5148-5152 ◽  
Author(s):  
James E. McDonald ◽  
Alexandre B. de Menezes ◽  
Heather E. Allison ◽  
Alan J. McCarthy
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Relative Abundance ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Sediment Surface ◽  
Rrna Gene ◽  
Freshwater Lakes ◽  
Lake Ecosystems ◽  
The 16S Rrna Gene

ABSTRACT PCR and quantitative PCR (qPCR) primers targeting the 16S rRNA gene were used to detect and quantify members of the genus Fibrobacter in lake water, sediment and colonized cotton taken from two freshwater lakes. Phylogenetic analysis identified two groups of sequences; those clustered with Fibrobacter succinogenes, the type species, and a defined cluster of clones loosely associated with several Fibrobacter sequences observed previously in clone libraries from freshwater environments. 16S rRNA gene sequences recovered in the same way from soil samples and ovine feces in the surrounding land were all F. succinogenes and did not include any from this group of the “freshwater” Fibrobacteres. In all cases, nested PCR was required to detect Fibrobacter 16S rRNA genes, and qPCR analysis of reverse transcribed bacterial community RNA confirmed their very low relative abundance on colonized cotton baits in the water column (at 0, 3, 7, 11, and 13 m) and on the sediment surface (<0.02% of total bacterial rRNA). However, in Esthwaite Water sediment itself, the relative abundance of fibrobacters was 2 orders of magnitude higher (ca. 1% of total bacterial rRNA). The presence of fibrobacters, including the cellulolytic rumen species F. succinogenes, on colonized cellulose samples and in lake sediment suggests that these organisms may contribute to the primary degradation of plant and algal biomass in freshwater lake ecosystems.

scholarly journals Power Analysis for Real-Time PCR Quantification of Genes in Activated Sludge and Analysis of the Variability Introduced by DNA Extraction

2003 ◽  
Vol 69 (11) ◽  
pp. 6597-6604 ◽  
Author(s):  
Hebe M. Dionisi ◽  
Gerda Harms ◽  
Alice C. Layton ◽  
Igrid R. Gregory ◽  
Jack Parker ◽  
...  
Keyword(s):  
16S Rrna ◽  
Activated Sludge ◽  
Real Time ◽  
Real Time Pcr ◽  
Power Analysis ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Pcr Assay ◽  
Pcr Assays

ABSTRACT The aims of this study were to determine the power of discrimination of the real-time PCR assay for monitoring fluctuations in microbial populations within activated sludge and to identify sample processing points where methodological changes are needed to minimize the variability in target quantification. DNA was extracted using a commercially available kit from mixed liquor samples taken from the aeration tank of four bench-scale activated-sludge reactors operating at 2-, 5-, 10-, and 20-day solid retention times, with mixed-liquor volatile suspended solid (MLVSS) values ranging from 260 to 2,610 mg/liter. Real-time PCR assays for bacterial and Nitrospira 16S rRNA genes were chosen because they represent, respectively, a highly abundant and a less-abundant bacterial target subject to clustering within the activated sludge matrix. The mean coefficient of variation in DNA yields (measured as microgram of DNA per milligram of MLVSS) in triplicate extractions of 12 different samples was 12.2%. Based on power analyses, the variability associated with DNA extraction had a small impact on the overall variability of the real-time PCR assay. Instead, a larger variability was associated with the PCR assay. The less-abundant target (Nitrospira 16S rRNA gene) had more variability than the highly abundant target (bacterial 16S rRNA gene), and samples from the lower-biomass reactors had more variability than samples from the higher-biomass reactors. Power analysis of real-time PCR assays indicated that three to five samples were necessary to detect a twofold increase in bacterial 16S rRNA genes, whereas three to five samples were required to detect a fivefold increase in Nitrospira 16S rRNA genes.

scholarly journals An inter-laboratory study to investigate the impact of the bioinformatics component on microbiome analysis using mock communities

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Denise M. O’Sullivan ◽  
Ronan M. Doyle ◽  
Sasithon Temisak ◽  
Nicholas Redshaw ◽  
Alexandra S. Whale ◽  
...  
Keyword(s):  
Microbial Community ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Relative Abundance ◽  
Amplicon Sequencing ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Microbiome Analysis ◽  
The Impact

AbstractDespite the advent of whole genome metagenomics, targeted approaches (such as 16S rRNA gene amplicon sequencing) continue to be valuable for determining the microbial composition of samples. Amplicon microbiome sequencing can be performed on clinical samples from a normally sterile site to determine the aetiology of an infection (usually single pathogen identification) or samples from more complex niches such as human mucosa or environmental samples where multiple microorganisms need to be identified. The methodologies are frequently applied to determine both presence of micro-organisms and their quantity or relative abundance. There are a number of technical steps required to perform microbial community profiling, many of which may have appreciable precision and bias that impacts final results. In order for these methods to be applied with the greatest accuracy, comparative studies across different laboratories are warranted. In this study we explored the impact of the bioinformatic approaches taken in different laboratories on microbiome assessment using 16S rRNA gene amplicon sequencing results. Data were generated from two mock microbial community samples which were amplified using primer sets spanning five different variable regions of 16S rRNA genes. The PCR-sequencing analysis included three technical repeats of the process to determine the repeatability of their methods. Thirteen laboratories participated in the study, and each analysed the same FASTQ files using their choice of pipeline. This study captured the methods used and the resulting sequence annotation and relative abundance output from bioinformatic analyses. Results were compared to digital PCR assessment of the absolute abundance of each target representing each organism in the mock microbial community samples and also to analyses of shotgun metagenome sequence data. This ring trial demonstrates that the choice of bioinformatic analysis pipeline alone can result in different estimations of the composition of the microbiome when using 16S rRNA gene amplicon sequencing data. The study observed differences in terms of both presence and abundance of organisms and provides a resource for ensuring reproducible pipeline development and application. The observed differences were especially prevalent when using custom databases and applying high stringency operational taxonomic unit (OTU) cut-off limits. In order to apply sequencing approaches with greater accuracy, the impact of different analytical steps needs to be clearly delineated and solutions devised to harmonise microbiome analysis results.

Differentiation Of Clarias Batrachus, C. Gariepinus And Heteropneustes Fossilis By Pcr-Sequencing Of Mitochondrial 16s Rrna Gene

2015 ◽  
Vol 41 (1) ◽  
pp. 51-58
Author(s):  
Mohammad Shamimul Alam ◽  
Hawa Jahan ◽  
Rowshan Ara Begum ◽  
Reza M Shahjahan
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Fish Larva ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Valuable Insight ◽  
Multiple Sequence ◽  
Pcr Rflp ◽  
Alternative Means

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

scholarly journals Microbiological and Geochemical Heterogeneity in an In Situ Uranium Bioremediation Field Site

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 ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Acid Volatile Sulfide ◽  
Rrna Gene ◽  
Gene Sequences ◽  
16S Rrna Gene Sequences ◽  
Geochemical Heterogeneity

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.

scholarly journals Extremely Acidophilic Protists from Acid Mine Drainage Host Rickettsiales-Lineage Endosymbionts That Have Intervening Sequences in Their 16S rRNA Genes

2003 ◽  
Vol 69 (9) ◽  
pp. 5512-5518 ◽  
Author(s):  
Brett J. Baker ◽  
Philip Hugenholtz ◽  
Scott C. Dawson ◽  
Jillian F. Banfield
Keyword(s):  
Acid Mine Drainage ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Mine Drainage ◽  
Close Association ◽  
Variable Region ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Acid Mine

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.

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