Dataset Information

Use of next-generation amplicon sequencing to study Blastocystis genetic diversity in a rural human population from Mexico.

ABSTRACT: BACKGROUND:The intestinal parasite Blastocystis is found in humans and animals around the world. It is spread through the consumption of contaminated food and water and has been associated with a variety of intestinal symptoms. Blastocystis is one of the most common intestinal parasites in humans, yet its prevalence and distribution in humans in North America is not well characterized. METHODS:Next-generation amplicon sequencing of a region of the Blastocystis SSU rRNA gene was applied to DNA extracted from fecal specimens obtained from 182 inhabitants of a rural population in Mexico to characterize Blastocystis prevalence, subtype distribution, and intra-host subtype diversity in humans. RESULTS:Of the 182 samples tested in this study, 68.1% (124) contained one or more Blastocystis subtypes. Subtype 3 was the most common subtype observed and was found in 81.5% of the positive samples. Subtype 1, 16.9% of the positive samples, and subtype 2, 17.7% of the positive samples, were also found in this population. Mixed infections were observed in 13.7% of the positive samples. In this population, the odds of having Blastocystis increased in adulthood (> 15 years; OR: 1.72, P < 0.0001), and the odds of having subtype 1 increased in the presence of farm animals (OR: 1.51, P = 0.03). The odds of having subtype 1, subtype 2, or a mixed infection decreased in the presence of cement flooring (OR: -?1.61, P = 0.005; OR: -?1.14, P = 0.03; OR: -?1.48, P = 0.02) possibly indicating socioeconomic factors are involved in the risk of acquiring one of these subtypes. CONCLUSIONS:These data contribute to our understanding of the epidemiology of Blastocystis infection in humans and can be used to shape future studies which aim to better characterize the transmission pathways and health outcomes of Blastocystis infections.

SUBMITTER: Rojas-Velazquez L

PROVIDER: S-EPMC6882168 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature

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Use of next-generation amplicon sequencing to study Blastocystis genetic diversity in a rural human population from Mexico.

Rojas-Velázquez Liliana L Maloney Jenny G JG Molokin Aleksey A Morán Patricia P Serrano-Vázquez Angélica A González Enrique E Pérez-Juárez Horacio H Ximénez Cecilia C Santin Monica M

Parasites & vectors 20191127 1

<h4>Background</h4>The intestinal parasite Blastocystis is found in humans and animals around the world. It is spread through the consumption of contaminated food and water and has been associated with a variety of intestinal symptoms. Blastocystis is one of the most common intestinal parasites in humans, yet its prevalence and distribution in humans in North America is not well characterized.<h4>Methods</h4>Next-generation amplicon sequencing of a region of the Blastocystis SSU rRNA gene was ap ...[more]

PMID: 31775832

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Project description:Background:Application of next-generation sequencing (NGS) to genomic DNA extracted from sewage offers a unique and cost-effective opportunity to study the genetic diversity of intestinal parasites. In this study, we used amplicon-based NGS to reveal and differentiate several common luminal intestinal parasitic protists, specifically Entamoeba, Endolimax, Iodamoeba, and Blastocystis, in sewage samples from Swedish treatment plants. Materials and methods:Influent sewage samples were subject to gradient centrifugation, DNA extraction and PCR-based amplification using three primer pairs designed for amplification of eukaryotic nuclear 18S ribosomal DNA. PCR products were sequenced using ILLUMINA® technology, and resulting sequences were annotated to species and subtype level using the in-house BION software, sequence clustering, and phylogenetic analysis. Results:A total of 26 samples from eight treatment plants in central/southern Sweden were analysed. Blastocystis sp. and Entamoeba moshkovskii were detected in all samples, and most samples (n?=?20) were positive for Entamoeba coli. Moreover, we detected Entamoeba histolytica, Entamoeba dispar, Entamoeba hartmanni, Endolimax nana, and Iodamoeba bütschlii in 1, 11, 4, 10, and 7 samples, respectively. The level of genetic divergence observed within E. nana and E. moshkovskii was 20.2% and 7.7%, respectively, across the ~400-bp region studied, and two clades of E. moshkovskii were found. As expected, Blastocystis sp. subtypes 1-4 were present in almost all samples; however, ST8 was present in 10 samples and was the only subtype not commonly found in humans that was present in multiple samples. Conclusions:Entamoeba and Blastocystis were identified as universal members of the "sewage microbiome". Blastocystis sp. ST8, which has been rarely reported in humans, was a very common finding, indicating that a hitherto unidentified but common host of ST8 contributed to the sewage influent. The study also provided substantial new insight into the intra-generic diversity of Entamoeba and Endolimax.

Project description:Structural and functional impacts of copy number variations (CNVs) on livestock genomes are not yet well understood. In this study, we have identified 1853 CNV regions (CNVRs) using population-scale sequencing data generated from 75 cattle of 8 breeds (Holstein, Angus, Jersey, Limousin, Romagnola, Brahman, Gir and Nelore). Individual genome sequence coverage ranged from 4 to 30 fold, with a mean of 11.8 fold. A total of 3.1% (87.5 Mb) of the cattle genome is predicted to be copy number variable, representing a substantial increase over the previous estimates (~2%). This dataset was highly correlated with array CGH data (r2 = 0.761) and was validated to be accurate with an estimated 12% false positive rate and a 19% false negative rate based on qPCR and array CGH, respectively. Hundreds of CNVs were found to be either breed specific or differentially variable across breeds, including the RICTOR gene in dairy breeds and the PNPLA3 gene in the beef breeds. In contrast, clusters of the PRP and PAG genes are duplicated in all sequenced animals, implicating that subfunctionalization, neofunctionalization or overdominance play a role in diversifying these fertility related genes. Further population-genetic analyses based on CNVs revealed the population structures of these taurine and indicine breeds and uncovered hundreds of positively selected CNV candidates near important functional genes. These CNV results provide a new glimpse of diverse selections during cattle speciation, domestication, breed formation, and recent genetic improvement. 25 animals were analyzed using a custom Nimblegen aCGH chip with 2.1 million probes. The reference animal chosen was L1 Dominette, a Hereford cow of European ancestry. The array was subjected to a dye-swap with the reference sample to test probe intensity fidelity. Single channel intensity data from the array was used in a digital aCGH analysis to compare aCGH copy number estimates to copy number estimates derived from sequence data. Briefly, the reference signal from all analyzed arrays was collected and a median signal intensity was calculated from probe intensities within the BTF3 gene. The copy number of the reference animal was then inferred by division of single channel probe intensities with the median intensity of the BTF3 gene. Next, test sample intensities were normalized by taking the log2 ratio of the test intensity divided by the normalized reference copy number for the probe. CN values derived from sequence data were also normalized in this fashion by taking the log2 of the ratio of NGS CN divided by aCGH reference copy number.

Dataset Information

Use of next-generation amplicon sequencing to study Blastocystis genetic diversity in a rural human population from Mexico.

Publications

Use of next-generation amplicon sequencing to study Blastocystis genetic diversity in a rural human population from Mexico.

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