An improved and extended dual-index multiplexed 16S rRNA sequencing for the Illumina HiSeq and MiSeq platform.

BACKGROUND: Recent advancements in next-generation sequencing (NGS) technology have ushered in significant improvements in sequencing speed and data throughput, thereby enabling the simultaneous analysis of a greater number of samples within a single sequencing run. This technology has proven particularly valuable in the context of microbial community profiling, offering a powerful tool for characterizing the microbial composition at the species level within a given sample. This profiling process typically involves the sequencing of 16S ribosomal RNA (rRNA) gene fragments. By scaling up the analysis to accommodate a substantial number of samples, sometimes as many as 2,000, it becomes possible to achieve cost-efficiency and minimize the introduction of potential batch effects. Our study was designed with the primary objective of devising an approach capable of facilitating the comprehensive analysis of 1,711 samples sourced from diverse origins, including oropharyngeal swabs, mouth cavity swabs, dental swabs, and human fecal samples. This analysis was based on data obtained from 16S rRNA metagenomic sequencing conducted on the Illumina MiSeq and HiSeq sequencing platforms. RESULTS: We have designed a custom set of 10-base pair indices specifically tailored for the preparation of libraries from amplicons derived from the V3-V4 region of the 16S rRNA gene. These indices are instrumental in the analysis of the microbial composition in clinical samples through sequencing on the Illumina MiSeq and HiSeq platforms. The utilization of our custom index set enables the consolidation of a significant number of libraries, enabling the efficient sequencing of these libraries in a single run. CONCLUSIONS: The unique array of 10-base pair indices that we have developed, in conjunction with our sequencing methodology, will prove highly valuable to laboratories engaged in sequencing on Illumina platforms or utilizing Illumina-compatible kits.

DNA methylation across the genome in aged human skeletal muscle tissue and muscle-derived cells: the role of HOX genes and physical activity.

Skeletal muscle tissue demonstrates global hypermethylation with age. However, methylome changes across the time-course of differentiation in aged human muscle derived cells, and larger coverage arrays in aged muscle tissue have not been undertaken. Using 850K DNA methylation arrays we compared the methylomes of young (27 ± 4.4 years) and aged (83 ± 4 years) human skeletal muscle and that of young/aged heterogenous muscle-derived human primary cells (HDMCs) over several time points of differentiation (0, 72 h, 7, 10 days). Aged muscle tissue was hypermethylated compared with young tissue, enriched for; pathways-in-cancer (including; focal adhesion, MAPK signaling, PI3K-Akt-mTOR signaling, p53 signaling, Jak-STAT signaling, TGF-beta and notch signaling), rap1-signaling, axon-guidance and hippo-signalling. Aged cells also demonstrated a hypermethylated profile in pathways; axon-guidance, adherens-junction and calcium-signaling, particularly at later timepoints of myotube formation, corresponding with reduced morphological differentiation and reductions in MyoD/Myogenin gene expression compared with young cells. While young cells showed little alterations in DNA methylation during differentiation, aged cells demonstrated extensive and significantly altered DNA methylation, particularly at 7 days of differentiation and most notably in focal adhesion and PI3K-AKT signalling pathways. While the methylomes were vastly different between muscle tissue and HDMCs, we identified a small number of CpG sites showing a hypermethylated state with age, in both muscle tissue and cells on genes KIF15, DYRK2, FHL2, MRPS33, ABCA17P. Most notably, differential methylation analysis of chromosomal regions identified three locations containing enrichment of 6-8 CpGs in the HOX family of genes altered with age. With HOXD10, HOXD9, HOXD8, HOXA3, HOXC9, HOXB1, HOXB3, HOXC-AS2 and HOXC10 all hypermethylated in aged tissue. In aged cells the same HOX genes (and additionally HOXC-AS3) displayed the most variable methylation at 7 days of differentiation versus young cells, with HOXD8, HOXC9, HOXB1 and HOXC-AS3 hypermethylated and HOXC10 and HOXC-AS2 hypomethylated. We also determined that there was an inverse relationship between DNA methylation and gene expression for HOXB1, HOXA3 and HOXC-AS3. Finally, increased physical activity in young adults was associated with oppositely regulating HOXB1 and HOXA3 methylation compared with age. Overall, we demonstrate that a considerable number of HOX genes are differentially epigenetically regulated in aged human skeletal muscle and HDMCs and increased physical activity may help prevent age-related epigenetic changes in these HOX genes.

[GSTP1, APC and RASSF1 gene methylation in prostate cancer samples: comparative analysis of MS-HRM method and Infinium HumanMethylation450 BeadChip beadchiparray diagnostic value]. / Status metilirovaniia genov GSTP1, APC i RASSF1 v obraztsakh raka predstatel'noi zhelezy cheloveka: sravnitel'nyi analiz diagnosticheskoi informativnosti metodov MS-HRM i gibridizatsii na DNK-chipakh illumina Infinium HumanMethylation450 BeadChip.

There is a clear need in molecular markers for prostate cancer (PC) risk stratification. Alteration of DNA methylation is one of processes that occur during ÐÑ progression. Methylation-sensitive PCR with high resolution melting curve analysis (MS-HRM) can be used for gene methylation analysis in routine laboratory practice. This method requires very small amounts of DNA for analysis. Numerous results have been accumulated on DNA methylation in PC samples analyzed by the Infinium HumanMethylation450 BeadChip (HM450). However, the consistency of MS-HRM results with chip hybridization results has not been examined yet. The aim of this study was to assess the consistency of results of GSTP1, APC and RASSF1 gene methylation analysis in ÐÑ biopsy samples obtained by MS-HRM and chip hybridization. The methylation levels of each gene determined by MS-HRM were statistically different in the group of PC tissue samples and the samples without signs of tumor growth. Chip hybridization data analysis confirmed the results obtained with the MS-HRM. Differences in methylation levels between tumor tissue and histologically intact tissue of each sample determined by MS-HRM and chip hybridization, were consistent with each other. Thus, we showed that the assessment of GSTP1, APC and RASSF1 gene methylation analysis using MS-HRM is suitable for the design of laboratory assays that will differentiate the PC tissue from the tissue without signs of tumor growth.

[Genome-wide analysis of DNA methylation in prostate cancer using the technology of Infinium HumanMethylation450 BeadChip (HM450)].

Using the technology of DNA chips Infinium HumanMethylation 450 BeadChip it was analyzed quantitative DNA methylation status in 12 paired samples of prostate adenocarcinoma, and morphologically altered tissues. Analysis of differentially methylated regions of the genome showed an association with abnormal status for 21610 and 3852 hypomethylated hyper-methylated CpG sites. Dominance in the cancer genome hypermethylated sites and their predominant localization in the regulatory regions of genes indicate their possible role in the implementation of mechanisms of gene suppression in the pathogenesis of prostate cancer (PCa). For 14 genes studied were characterized array maximum values hypermethylation in promoter region (> 50% CpG sites) in combination with a high level of methylation differences between treatment groups (> 40%). Role of hypermethylation in some of them: AOX1, KLF8, ZNF154, TMEM106A in the pathogenesis of prostate cancer has been showed previously. Hypermethylation of genes ACSS3, TAC1, TUBA4B, ZSCAN12 not previously been shown for prostate cancer, but is characterized by the association with other cancers. In turn, the differences in the levels of methylation in genes GPRASP1, NKX2-6, ARX, CYBA, EPSTI1, RHCG been documented as a result of a number of genome-research oncology, but has not been studied in detail. To assess the diagnostic potential of epigenetic markers of prostate cancer there was carried out unbiased selection of individual CpG sites most reliably discriminate against tumor samples from a group of no tumor samples. In selected diagnostic model based on logistic regression included 9 CpG sites. Validation of the model was carried out on an independent dataset of methylation of 40 paired samples from the prostate cancer project Atlas of Cancer Genome (TCGA) analyzed on the same version of the DNA chip. Summarized rates of diagnostic informativeness of a model (specificity 95%, sensitivity of 97%, the area under the curve of the diagnostic test (ROC) - 0,96), obtained after validation, allow us to consider these CpG Sites as potential markers for molecular diagnosis of prostate cancer.

[Metagenomic analysis of taxonomic and functional changes in gut microbiota of patients with alcoholic dependence syndrome].

Here we present the first metagenomic study of gut microbiota in patients with alcohol dependence syndrome (ADS) performed in the whole-genome ("shotgun") format. Taxonomic analysis highlighted changes in community "drivers" abundance previously associated with inflammatory processes (including increase in Ruminococcus gnavus and torques, as well as decrease in Faecalibacterium and Akkermansia). Microbiota of alcoholics manifested presence of specific opportunistic pathogens rarely detected in healthy control subjects of the world. Differential analysis of metabolic potential basing on changes in KEGG Orthology groups abundance revealed increase in pathways associated with response to oxidative stress. Analysis of two specific gene groups--alcohol metabolism and virulence factors--also showed increase in comparison with the control groups. We suggest that gut microbiota distinct in alcoholics by both taxonomic and functional composition plays role in modulating the effect of alcohol on host organism.

SOD2 gene polymorphism and muscle damage markers in elite athletes.

Exercise-induced oxidative stress is a state that primarily occurs in athletes involved in high-intensity sports when pro-oxidants overwhelm the antioxidant defense system to oxidize proteins, lipids, and nucleic acids. During exercise, oxidative stress is linked to muscle metabolism and muscle damage, because exercise increases free radical production. The T allele of the Ala16Val (rs4880 C/T) polymorphism in the mitochondrial superoxide dismutase 2 (SOD2) gene has been reported to reduce SOD2 efficiency against oxidative stress. In the present study we tested the hypothesis that the SOD2 TT genotype would be underrepresented in elite athletes involved in high-intensity sports and associated with increased values of muscle and liver damage biomarkers. The study involved 2664 Caucasian (2262 Russian and 402 Polish) athletes. SOD2 genotype and allele frequencies were compared to 917 controls. Muscle and liver damage markers [creatine kinase (CK), creatinine, alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP)] were examined in serum from 1444 Russian athletes. The frequency of the SOD2 TT genotype (18.6%) was significantly lower in power/strength athletes (n = 524) compared to controls (25.0%, p = 0.0076) or athletes involved in low-intensity sports (n = 180; 33.9%, p < 0.0001). Furthermore, the SOD2 T allele was significantly associated with increased activity of CK (females: p = 0.0144) and creatinine level (females: p = 0.0276; males: p = 0.0135) in athletes. Our data show that the SOD2 TT genotype might be unfavorable for high-intensity athletic events.

[Variability in the relative quantity of human DNA resulted from metagenomic analysis of gut microbiota].

We conducted the comparative study of seven different methods of total DNA extraction from human feces. All these methods are recommended in protocols for metagenomic analysis of human gut microbiota. We studied the relative quantity of human DNA calculated from shotgun sequencing on a SOLiD 4 genetic analyzer of metagenomic samples. It was shown that either initial amount of feces or a method applied for total DNA extraction do not affect on final relative human DNA abundance, which is less than 1% in healthy people. Invariance of this parameter allows to consider increased abundance of human DNA in metagenomic samples as a potential marker of inflammatory bowel diseases.

A method for identification of vaginal epithelial microflora by the analysis of 16S ribosomal RNA gene.

Analysis of 16S ribosomal RNA gene was carried out in 2 DNA samples isolated from vaginal epithelial smears from women suffering from bacterial vaginosis. The composition of vaginal epithelial microbiocenosis in bacterial vaginosis was determined and its significant difference from normocenosis was shown. A laboratory protocol for identification of vaginal epithelial microflora was developed on the basis of 16S ribosomal RNA gene analysis.