Effects of temperature and predator on the persistence of host-specific Bacteroides-Prevotella genetic markers in water

2013 ◽  
Vol 67 (4) ◽  
pp. 838-845 ◽  
Author(s):  
Ayano Kobayashi ◽  
Daisuke Sano ◽  
Satoshi Okabe
Keyword(s):  
Water Temperature ◽  
Genetic Markers ◽  
Water Environment ◽  
Fecal Contamination ◽  
Critical Factor ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Effects Of Temperature ◽  
Agitation Time ◽  
Human Specific

Genetic markers derived from Bacteroidales spp. have been proposed as promising indicators for fecal contamination in the water environment. However, little is known about the persistency of Bacteroidales spp. 16S rRNA genetic markers in the natural environment, which hampers the precise identification of fecal contamination sources. In this study, the persistency of human-specific Bacteroidales spp. genetic markers in river water was investigated during a 3-week agitation. The copy number of Bacteroidales spp. genetic marker was decreased with agitation time, and was very sensitive to water temperature. After the 3-week agitation, three clones of 18S rRNA gene related to Glaucoma scintillans, Spumella-like flagellate, and Colpidium campylum were acquired. The presence of predators that can prey on target bacteria could also be a critical factor affecting the quantified value of genetic markers. It is very important to take these factors, water temperature and the presence of predator, into account for predicting the fate of genetic markers to accurately identify fecal pollution sources.

Use of Biochemical Genetic Markers to Discriminate between Adductor Muscles of the Sea Scallop (Placopecten magellanicus) and the Iceland Scallop (Chlamys islandica)

1993 ◽  
Vol 50 (6) ◽  
pp. 1222-1228 ◽  
Author(s):  
E. Kenchington ◽  
K. S. Naidu ◽  
D. L. Roddick ◽  
D. I. Cook ◽  
E. Zouros
Keyword(s):  
Genetic Markers ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Placopecten Magellanicus ◽  
Sea Scallop ◽  
Chlamys Islandica ◽  
Adductor Muscles ◽  
Enforcement Programme ◽  
Iceland Scallop ◽  
Species Specific

Three biochemical techniques were applied to adductor muscles of Placopecten magellanicus and Chlamys islandica, two commercially important scallops, to search for species-specific genetic markers. Allozyme electrophoresis identified two enzyme systems, mannose phosphate isomerase and glutamic oxaloacetate transaminase, which appear to be diagnostic. Sequencing of the 18S rRNA gene in each species showed 15 nucleotide differences over 1815 base pairs. Digestion of the gene with the restriction enzyme XHO I released two fragments in Placopecten and three in Chlamys. All three techniques could be developed for management purposes as part of an enforcement programme to identify illegally caught scallops.

scholarly journals Barcoding in trypanosomes

Parasitology ◽  
2017 ◽  
Vol 145 (5) ◽  
pp. 563-573 ◽  
Author(s):  
RACHEL HUTCHINSON ◽  
JAMIE R. STEVENS
Keyword(s):  
Genetic Markers ◽  
Molecular Diagnostics ◽  
Potential Application ◽  
18S Rrna ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Detection And Identification ◽  
Potential Alternative ◽  
Genetic Barcoding ◽  
The Ideal

SUMMARYTrypanosomes (genus Trypanosoma) are parasites of humans, and wild and domestic mammals, in which they cause several economically and socially important diseases, including sleeping sickness in Africa and Chagas disease in the Americas. Despite the development of numerous molecular diagnostics and increasing awareness of the importance of these neglected parasites, there is currently no universal genetic barcoding marker available for trypanosomes. In this review we provide an overview of the methods used for trypanosome detection and identification, discuss the potential application of different barcoding techniques and examine the requirements of the ‘ideal’ trypanosome genetic barcode. In addition, we explore potential alternative genetic markers for barcoding Trypanosoma species, including an analysis of phylogenetically informative nucleotide changes along the length of the 18S rRNA gene.

Isolation of Bacteroides from fish and human fecal samples for identification of unique molecular markers

2013 ◽  
Vol 59 (12) ◽  
pp. 771-777 ◽  
Author(s):  
Leila Kabiri ◽  
Absar Alum ◽  
Channah Rock ◽  
Jean E. McLain ◽  
Morteza Abbaszadegan
Keyword(s):  
Molecular Markers ◽  
Natural Waters ◽  
Fecal Contamination ◽  
Rrna Gene ◽  
Significant Similarity ◽  
Fecal Samples ◽  
Cultured Fish ◽  
Unique Markers ◽  
Current Sequence ◽  
Human Specific

Bacteroides molecular markers have been used to identify human fecal contamination in natural waters, but recent work in our laboratory confirmed cross-amplification of several human-specific Bacteroides spp. assays with fecal DNA from fish. For identification of unique molecular markers, Bacteroides from human (n = 4) and fish (n = 7) fecal samples were cultured and their identities were further confirmed using Rapid ID 32A API strips. The 16S rDNA from multiple isolates from each sample was PCR amplified, cloned, and sequenced to identify unique markers for development of more stringent human-specific assays. In human feces, Bacteroides vulgatus was the dominant species (75% of isolates), whereas in tilapia feces, Bacteroides eggerthii was dominant (66%). Bacteroides from grass carp, channel catfish, and blue catfish may include Bacteroides uniformis, Bacteroides ovatus, or Bacteroides stercoris. Phylogenic analyses of the 16S rRNA gene sequences showed distinct Bacteroides groupings from each fish species, while human sequences clustered with known B. vulgatus. None of the fish isolates showed significant similarity to Bacteroides sequences currently deposited in NCBI (National Center for Biotechnology Information). This study expands the current sequence database of cultured fish Bacteroides. Such data are essential for identification of unique molecular markers in human Bacteroides that can be utilized in differentiating fish and human fecal contamination in water samples.

scholarly journals Quantitative PCR for Genetic Markers of Human Fecal Pollution

2009 ◽  
Vol 75 (17) ◽  
pp. 5507-5513 ◽  
Author(s):  
Orin C. Shanks ◽  
Catherine A. Kelty ◽  
Mano Sivaganesan ◽  
Manju Varma ◽  
Richard A. Haugland
Keyword(s):  
Quantitative Pcr ◽  
Genetic Markers ◽  
Quantitative Methods ◽  
Animal Species ◽  
Fecal Pollution ◽  
Rrna Gene ◽  
Target Dna ◽  
Pcr Assays ◽  
Wastewater Samples ◽  
Human Specific

ABSTRACT Assessment of health risk and fecal bacterial loads associated with human fecal pollution requires reliable host-specific analytical methods and a rapid quantification approach. We report the development of quantitative PCR assays for quantification of two recently described human-specific genetic markers targeting Bacteroidales-like cell surface-associated genes. Each assay exhibited a range of quantification from 10 to 1 � 106 copies of target DNA. For each assay, internal amplification controls were developed to detect the presence or absence of amplification inhibitors. The assays predominantly detected human fecal specimens and exhibited specificity levels greater than 97% when tested against 265 fecal DNA extracts from 22 different animal species. The abundance of each human-specific genetic marker in primary effluent wastewater samples collected from 20 geographically distinct locations was measured and compared to quantities estimated by real-time PCR assays specific for rRNA gene sequences from total Bacteroidales and enterococcal fecal microorganisms. Assay performances combined with the prevalence of DNA targets in sewage samples provide experimental evidence supporting the potential application of these quantitative methods for monitoring fecal pollution in ambient environmental waters.

scholarly journals Analytical validation of a real-time hydrolysis probe PCR assay for quantifying Plasmodium falciparum parasites in experimentally infected human adults

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Claire Y. T. Wang ◽  
Emma L. Ballard ◽  
Zuleima Pava ◽  
Louise Marquart ◽  
Jane Gaydon ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Plasmodium Falciparum ◽  
18S Rrna ◽  
Drug Efficacy ◽  
18S Rrna Gene ◽  
Molecular Techniques ◽  
Qpcr Assay ◽  
Rrna Gene ◽  
Analytical Sensitivity ◽  
Blood Samples

Abstract Background Volunteer infection studies have become a standard model for evaluating drug efficacy against Plasmodium infections. Molecular techniques such as qPCR are used in these studies due to their ability to provide robust and accurate estimates of parasitaemia at increased sensitivity compared to microscopy. The validity and reliability of assays need to be ensured when used to evaluate the efficacy of candidate drugs in clinical trials. Methods A previously described 18S rRNA gene qPCR assay for quantifying Plasmodium falciparum in blood samples was evaluated. Assay performance characteristics including analytical sensitivity, reportable range, precision, accuracy and specificity were assessed using experimental data and data compiled from phase 1 volunteer infection studies conducted between 2013 and 2019. Guidelines for validation of laboratory-developed molecular assays were followed. Results The reportable range was 1.50 to 6.50 log10 parasites/mL with a limit of detection of 2.045 log10 parasites/mL of whole blood based on a parasite diluted standard series over this range. The assay was highly reproducible with minimal intra-assay (SD = 0.456 quantification cycle (Cq) units [0.137 log10 parasites/mL] over 21 replicates) and inter-assay (SD = 0.604 Cq units [0.182 log10 parasites/mL] over 786 qPCR runs) variability. Through an external quality assurance program, the QIMR assay was shown to generate accurate results (quantitative bias + 0.019 log10 parasites/mL against nominal values). Specificity was 100% after assessing 164 parasite-free human blood samples. Conclusions The 18S rRNA gene qPCR assay is specific and highly reproducible and can provide reliable and accurate parasite quantification. The assay is considered fit for use in evaluating drug efficacy in malaria clinical trials.

scholarly journals 16S rRNA gene and 18S rRNA gene diversity in microbial mat communities in meltwater ponds on the McMurdo Ice Shelf, Antarctica

Polar Biology ◽  
2021 ◽  
Author(s):  
Eleanor E. Jackson ◽  
Ian Hawes ◽  
Anne D. Jungblut
Keyword(s):  
16S Rrna ◽  
18S Rrna ◽  
High Throughput Sequencing ◽  
Microbial Mats ◽  
Gene Diversity ◽  
Salinity Gradient ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Ice Shelf ◽  
The Impact

AbstractThe undulating ice of the McMurdo Ice Shelf, Southern Victoria Land, supports one of the largest networks of ice-based, multiyear meltwater pond habitats in Antarctica, where microbial mats are abundant and contribute most of the biomass and biodiversity. We used 16S rRNA and 18S rRNA gene high-throughput sequencing to compare variance of the community structure in microbial mats within and between ponds with different salinities and pH. Proteobacteria and Cyanobacteria were the most abundant phyla, and composition at OTU level was highly specific for the meltwater ponds with strong community sorting along the salinity gradient. Our study provides the first detailed evaluation of eukaryote communities for the McMurdo Ice Shelf using the 18S rRNA gene. They were dominated by Ochrophyta, Chlorophyta and Ciliophora, consistent with previous microscopic analyses, but many OTUs belonging to less well-described heterotrophic protists from Antarctic ice shelves were also identified including Amoebozoa, Rhizaria and Labyrinthulea. Comparison of 16S and 18S rRNA gene communities showed that the Eukaryotes had lower richness and greater similarity between ponds in comparison with Bacteria and Archaea communities on the McMurdo Ice shelf. While there was a weak correlation between community dissimilarity and geographic distance, the congruity of microbial assemblages within ponds, especially for Bacteria and Archaea, implies strong habitat filtering in ice shelf meltwater pond ecosystems, especially due to salinity. These findings help to understand processes that are important in sustaining biodiversity and the impact of climate change on ice-based aquatic habitats in Antarctica.

scholarly journals Markers of Genetic Variation in Blue Gourami (Trichogaster trichopterus) as a Model for Labyrinth Fish

Biology ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 228
Author(s):  
Gad Degani ◽  
Isana Veksler-Lublinsky ◽  
Ari Meerson
Keyword(s):  
Growth Hormone ◽  
Genetic Variation ◽  
Genetic Markers ◽  
Basic Research ◽  
Coi Gene ◽  
12S Rrna ◽  
Rrna Gene ◽  
Somatotropic Axis ◽  
Genes Encoding ◽  
Growth And Reproduction

Markers of genetic variation between species are important for both applied and basic research. Here, various genes of the blue gourami (Trichogaster trichopterus, suborder Anabantoidei, a model labyrinth fish), many of them involved in growth and reproduction, are reviewed as markers of genetic variation. The genes encoding the following hormones are described: kisspeptins 1 and 2, gonadotropin-releasing hormones 1, 2, and 3, growth hormone, somatolactin, prolactin, follicle- stimulating hormone and luteinizing hormone, as well as mitochondrial genes encoding cytochrome b and 12S rRNA. Genetic markers in blue gourami, representing the suborder Anabantoidei, differ from those in other bony fishes. The sequence of the mitochondrial cytochrome c oxidase subunit 1 (COI) gene of blue gourami is often used to study the Anabantoidei suborder. Among the genes involved in controlling growth and reproduction, the most suitable genetic markers for distinguishing between species of the Anabantoidei have functions in the hypothalamic–pituitary–somatotropic axis: pituitary adenylate cyclase-activating polypeptide and growth hormone, and the 12S rRNA gene.

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