Maksim L. Filipenko

Comparison of fluorescent intercalating dyes for quantitative loop-mediated isothermal amplification (qLAMP).

Real-time or quantitative loop-mediated isothermal amplification (qLAMP) is a promising technique for the accurate detection of pathogens in organisms and the environment. Here we present a comparative study of the performance of six fluorescent intercalating dyes-SYTO-9, SYTO-13, SYTO-82, SYBR Green I, SYBR Gold, EvaGreen-in three different qLAMP model systems. SYTO-9 and SYTO-82, which had the best results, were used for additional enzyme and template titration studies. SYTO-82 demonstrated the best combination of time-to-threshold (Tt) and signal-to-noise ratio (SNR).

Association of the MTHFR 1298A>C (rs1801131) polymorphism with speed and strength sports in Russian and Polish athletes

Abstract It has been suggested that DNA hypomethylation because of poorer effectiveness of the 5,10-methylenetetrahydrofolate reductase (MTHFR) enzyme induces muscular growth. We hypothesised that the common, functional 1298A>C polymorphism in the MTHFR gene is associated with athletic status. To test this hypothesis, we investigated the distribution of the 1298A>C variant in Polish (n = 302) and Russian (n = 842) athletes divided into four groups: endurance, strength-endurance, sprint-strength and strength-endurance, as well as in 1540 control participants. We found different genotypes (the AC heterozygote advantage) and allele distributions among sprint-strength athletes and strength athletes than the groups of sedentary controls for each nationality. In the combined study, the allelic frequencies for the 1298C variant were 35.6% in sprint-strength athletes (OR 1.18 [1.02–1.36], P = 0.024 vs. controls) and 38.6% in strength athletes (OR 1.34 [1.10–1.64], P = 0.003 vs. controls). The results of the initial and repetition studies as well as the combined analysis suggest that the functional 1298A>C polymorphism in the MTHFR gene is associated with athletic status. The presence of the C allele seems to be beneficial in sprint-strength and strength athletes. It needs to be established whether and to what extent this effect is mediated by alteration in DNA methylation status.

Allele Frequency and Genotype Distribution of 9 SNPs in the Kazakh Population

Background: Determining the allelic variants of xenobiotic biotransformation genes is important, especially for prescribing personalised drugs. Knowledge of the allele distribution in different populations may be considered when selecting the preferred medication regimen. The frequency of CYP2C9, VKORC1, CYP4F2, GGCX, CYP2D6 and CYP1A2 genes has been studied in many populations, but the populations in Central Asia have not yet been investigated. Methods and materials: Using real-time PCR and direct sequencing-based methods, the current study assessed the frequencies of 9 polymorphisms of genes encoding enzymes involved in drug metabolism in 450 healthy individuals from different regions of Kazakhstan and 575 healthy individuals from the West-Siberian region of Russia. Results: The allele frequencies in the Kazakh population were determined for CYP2C9*2 (0.02), CYP2C9*3 (0.03), VKORC1 c. 173+1369G>C, VKORC1 c. 173+1000C>T (0.72, СYP4F2 (0.31), GGCX (0.04), CYP2D6*4 (0.07), CYP2D6*3 (0.01) and CYP1A2*1F (0.35). All alleles were in Hardy–Weinberg equilibrium (p > 0.05). The allele frequencies in the Russian population were as follows: CYP2C9*2, 0.08; CYP2C9*3, 0.08; VKORC1 (c. 173+1000C>T), 0.40; VKORC1 (c. 173+1369G>C), 0.41; СYP4F2 (c. 1297G>A), 0.24; GGCX (c. 1913+45G>C), 0.08; CYP2D6*3, 0.15; CYP2D6*4, 0.22; and CYP1A2*1F (c. -9-154C>A), 0.31. All alleles were in Hardy–Weinberg equilibrium (p>0.05), except GGCX (p=0.04). Conclusion: The Kazakh population allele frequency was between the Caucasian and Asian populations for nearly all of the studied gene allele variants.

Selection of naturally occurring autoantibodies to interleukin-18 from phage display library

Four unique phage single-chain variable fragments (scFvs) to recombinant human interleukin 18 (IL-18) has been selected from a naïve combinatorial library of human scFvs. Binding of unique phage antibodies with IL-18 was tested by ELISA and Western-blotting. No cross reactivity with tumor necrosis factor α, interferons α and γ was shown for the selected antibodies. The gene segments encoding V(D)J regions of selected antibodies exhibited a high degree of homology to germline genes, therefore we suggest that the selected scFvs belong to repertoire of naïve autoantibodies.

Use of the VH6-1 gene segment to code for anti-interleukin-18 autoantibodies in multiple sclerosis

We investigated whether levels and repertoires of anti-interleukin-18 (IL-18) autoantibodies (auto-Abs) differ in multiple sclerosis (MS) patients and healthy donors (HDs). IL-18 concentration in MS patients’ sera was higher than in HD, but the level of anti-IL-18 auto-Abs was lower in MS patients. Correlation patterns of IL-18/anti-IL-18 auto-Abs system differed in HD and MS patients, so we have compared segment composition of the anti-IL-18 single-chain variable fragments (scFvs) selected from MS and naïve phage display libraries. Considerable differences between anti-IL-18 auto-Abs of these libraries were found. MS panel contained auto-Abs displaying both signs of “fetal” and somatically hypermutated repertoires. Naïve panel mainly contained the naïve antibodies. These variations from the norm are possible results of abnormal regulation of the repertoire perhaps determined by remodeling of the molecular mechanisms involved in the V(D)J recombination and/or abnormal selection by antigen in MS pathogenesis.

Derivatives of Bst-like Gss-polymerase with improved processivity and inhibitor tolerance

Abstract At the moment, one of the actual trends in medical diagnostics is a development of methods for practical applications such as point-of-care testing, POCT or research tools, for example, whole genome amplification, WGA. All the techniques are based on using of specific DNA polymerases having strand displacement activity, high synthetic processivity, fidelity and, most significantly, tolerance to contaminants, appearing from analysed biological samples or collected under purification procedures. Here, we have designed a set of fusion enzymes based on catalytic domain of DNA polymerase I from Geobacillus sp. 777 with DNA-binding domain of DNA ligase Pyrococcus abyssi and Sto7d protein from Sulfolobus tokodaii, analogue of Sso7d. Designed chimeric DNA polymerases DBD-Gss, Sto-Gss and Gss-Sto exhibited the same level of thermal stability, thermal transferase activity and fidelity as native Gss; however, the processivity was increased up to 3-fold, leading to about 4-fold of DNA product in WGA which is much more exiting. The attachment of DNA-binding proteins enhanced the inhibitor tolerance of chimeric polymerases in loop-mediated isothermal amplification to several of the most common DNA sample contaminants—urea and whole blood, heparin, ethylenediaminetetraacetic acid, NaCl, ethanol. Therefore, chimeric Bst-like Gss-polymerase will be promising tool for both WGA and POCT due to increased processivity and inhibitor tolerance.

Association of GSTM1 (del),GSTP1 (Ile105Val) genetic polymorphisms and smoking in the family with congenital malformations

Background. The association of GSTM1 (del) and GSTP1 (Ile105Val) polymorphisms with congenital malformations (CMs) actively studied. However, the results of various studies are conflicting. This study aims to investigate the association of GSTM1 (del), GSTP1 (Ile105Val) genetic polymorphisms and smoking in the family with congenital malformations in the newborn. Method. We studied 94 newborn with CMs and 125 healthy newborn. Null genotype of GSTM1 was identified through multiplex real-time PCR, and GSTP1 gene (Ile105Val) polymorphism was determined through TaqMan-real-time PCR. Results. The study showed that polymorphic loci of GSTM1 (del) and GSTP1 (Ile105Val) genes were not associated with the risk of congenital malformations in the newborn (P = 0,46 and P = 0,47). When comparing the frequencies of genotypes the GSTP1 (Ile105Val) gene in newborn with CMs in the families of smokers with those of healthy newborn in non-smoking families statistically significant differences between them were found (P = 0,02). The genotype Ile/Val in children was associated with CMs (ORg + f = 2,59; 95 % CI: 1,05- 6,35), while the homozygous genotype Ile/Ile in newborn was associated with a protective effect to CMs (ORg + f = 0,30; 95 % CI: 0,12-0,72). Possibly, the association of the homozygous genotype Val/Val did not reach statistical significance due to a small number of children surveyed. Conclusion. The smoking in the family increases the risk of CMs in the newborn with genotypes of GSTP1 gene (Ile105Val) polymorphism.