Heritability estimates of endurance-related phenotypes: A systematic review and meta-analysis.

The aim of this study was to clarify heritability estimates for endurance-related phenotypes and the underlying factors affecting these estimates. A systematic literature search was conducted for studies reporting heritability estimates of endurance-related phenotypes using the PubMed database (up to 30 September 2016). Studies that estimated the heritability of maximal oxygen uptake (V˙O2max), submaximal endurance phenotypes, and endurance performance were selected. The weighted mean heritability for endurance-related phenotypes was calculated using a random-effects model. A total of 15 studies were selected via a systematic review. Meta-analysis revealed that the weighted means of the heritability of V˙O2max absolute values and those adjusted for body weight and for fat-free mass were 0.68 (95% CI: 0.59-0.77), 0.56 (95% CI: 0.47-0.65), and 0.44 (95% CI: 0.13-0.75), respectively. There was a significant difference in the weighted means of the heritability of V˙O2max across these different adjustment methods (P < .05). Moreover, there was evidence of statistical heterogeneity in the heritability estimates among studies. Meta-regression analysis revealed that sex could partially explain the heterogeneity in the V˙O2max heritability estimates adjusted by body weight. For submaximal endurance phenotypes and endurance performance, the weighted mean heritabilities were 0.49 (95% CI: 0.33-0.65) and 0.53 (95% CI: 0.27-0.78), respectively. There was statistically significant heterogeneity in the heritability estimates reported among the studies, and we could not identify the specific factors explaining the heterogeneity. Although existing studies indicate that genetic factors account for 44%-68% of the variability in endurance-related phenotypes, further studies are necessary to clarify these values.

Association analysis of the ACTN3 R577X polymorphism with passive muscle stiffness and muscle strain injury.

Passive muscle stiffness is considered to be a major factor affecting joint flexibility and is thought to relate to the occurrence of muscle strain injury. In skinned muscle fiber experiments, the R577X polymorphism of the α-actinin-3 gene (ACTN3) has been associated with passive muscle stiffness. Our primary purpose was to clarify whether the ACTN3 R577X polymorphism influences passive stiffness of human muscle in vivo. We also examined whether the ACTN3 R577X polymorphism is associated with the occurrence of hamstring strain injury. Seventy-six healthy young male subjects were genotyped for the ACTN3 R577X (rs1815739) polymorphism. Shear modulus (an index of stiffness) of each hamstring muscle (biceps femoris, semitendinosus, and semimembranosus) was assessed using ultrasound shear wave elastography, and history of hamstring strain injury was collected via a questionnaire. The muscle shear moduli of the semitendinosus and semimembranosus were significantly higher in R-allele (RR + RX genotype) carriers than in XX genotype carriers, whereas the shear modulus of the biceps femoris did not differ among the ACTN3 R577X genotypes. Frequency of past hamstring strain injury also did not differ between the 3 genotypes nor between the R-allele and XX genotype carriers. This study indicates that RR and RX genotypes of the ACTN3 R577X polymorphism (corresponding to the presence of α-actinin-3 in type II muscle fibers) are associated with increased passive muscle stiffness of the human hamstring in vivo. However, this altered mechanical property might not affect the risk of hamstring muscle strain injury.

Heritability estimates of muscle strength-related phenotypes: A systematic review and meta-analysis.

The purpose of this study was to clarify the heritability estimates of human muscle strength-related phenotypes (H2 -msp). A systematic literature search was conducted using PubMed (through August 22, 2016). Studies reporting the H2 -msp for healthy subjects in a sedentary state were included. Random-effects models were used to calculate the weighted mean heritability estimates. Moreover, subgroup analyses were performed based on phenotypic categories (eg, grip strength, isotonic strength, jumping ability). Sensitivity analyses were also conducted to investigate potential sources of heterogeneity of H2 -msp, which included age and sex. Twenty-four articles including 58 measurements were included in the meta-analysis. The weighted mean H2 -msp for all 58 measurements was 0.52 (95% confidence intervals [CI]: 0.48-0.56), with high heterogeneity (I2 =91.0%, P<.001). Subgroup analysis showed that the heritability of isometric grip strength, other isometric strength, isotonic strength, isokinetic strength, jumping ability, and other power measurements was 0.56 (95% CI: 0.46-0.67), 0.49 (0.47-0.52), 0.49 (0.32-0.67), 0.49 (0.37-0.61), 0.55 (0.45-0.65), and 0.51 (0.31-0.70), respectively. The H2 -msp decreased with age (P<.05). In conclusion, our results indicate that the influence of genetic and environmental factors on muscle strength-related phenotypes is comparable. Moreover, the role of environmental factors increased with age. These findings may contribute toward an understanding of muscle strength-related phenotypes.

CNTFR Genotype and Sprint/power Performance: Case-control Association and Functional Studies.

The aim of this study was to investigate whether rs41274853 in the 3'-untranslated region of the ciliary neurotrophic factor receptor gene (CNTFR) is associated with elite sprint/power athletic status and assess its functional significance. A total of 211 Japanese sprint/power track and field athletes (62 international, 72 national, and 77 regional athletes) and 814 Japanese controls were genotyped at rs41274853. Luciferase reporter assay was conducted to investigate whether this C-to-T polymorphism affects binding of microRNA miR-675-5p to this region. The TT genotype was significantly more frequent among international sprint/power athletes (19.4%) than in the controls after Bonferroni correction (7.9%, P=0.036, OR=2.81 [95% CI: 1.43-5.55]). Furthermore, in non-athletic young/middle-aged men (n=132), TT genotype carriers exhibited significantly greater leg extension power (26.6±5.4 vs. 24.0±5.4 W/kg BW, P=0.019) and vertical jump performance (50.1±6.9 vs. 47.9±7.5 cm, P=0.047) than the CC+CT genotype carriers. Reporter assays revealed that the miR-675-5p binds to this polymorphic region within the CNTFR mRNA, irrespective of the rs41274853 allele present. Although the functional significance of the rs41274853 polymorphism remains unclear, the CNTFR is one of the candidate genes contributing to sprint/power performance.

ACTN3 R577X genotype is associated with sprinting in elite Japanese athletes.

The ACTN3 R577X genotype has been found to associate with sprint/power phenotypes in all elite athlete cohorts investigated. This association has not been extensively studied in elite Asian athletes. The present study was undertaken to investigate the association between the ACTN3 R577X genotype and elite Japanese track and field athlete status. 299 elite Japanese track and field athletes (134 sprint/power athletes; 165 endurance/middle-power athletes) and 649 Japanese controls were genotyped for the ACTN3 R577X polymorphism. All athletes were of national or international level. Sprint/power athletes showed a higher frequency of RR + RX genotype than controls (111/134 [82.8%] vs. 478/649 [73.7%], P = 0.025 under the R-dominant model), while there was no significant difference between endurance/middle-power athletes and controls (126/165 [76.4%] vs. 478/649 [73.7%], P = 0.48 under the R-dominant model). Sprinters with the RR + RX genotype had significantly faster personal best times for the 100 m than those with XX genotype (10.42 ± 0.05 s vs. 10.64 ± 0.09 s, P = 0.042); no such association was found in the 400 m sprinters (47.02 ± 0.36 s vs. 47.56 ± 0.99 s, P = 0.62). ACTN3 R577X genotype is associated with sprint/power performance in elite Japanese track and field athletes, especially short sprint performance.

Polymorphisms in the control region of mitochondrial DNA associated with elite Japanese athlete status.

The control region of mitochondrial DNA (mtDNA) contains the main regulatory elements for mtDNA replication and transcription. Certain polymorphisms in this region would, therefore, contribute to elite athletic performance, because mitochondrial function is one of determinants of physical performance. The present study was undertaken to examine the effect of polymorphisms in this region on elite athlete status by sequencing the mtDNA control region. Subjects comprised 185 elite Japanese athletes who had represented Japan at international competitions (i.e., 100 endurance/middle-power athletes: EMA; 85 sprint/power athletes: SPA), and 672 Japanese controls (CON). The mtDNA control region was analyzed by direct sequencing. Frequency differences of polymorphisms (minor allele frequency ≥ 0.05) in the mtDNA control region between EMA, SPA, and CON were examined. EMA displayed excess of three polymorphisms [m.152T>C, m.514(CA)n repeat (n ≥ 5), and poly-C stretch at m.568-573 (C ≥ 7)] compared with CON. On the other hand, SPA showed greater frequency of the m.204T>C polymorphism compared with CON. In addition, none of the SPA had m.16278C>T polymorphism, whereas the frequencies of this polymorphism in CON and EMA were 8.3% and 10.0%, respectively. These findings imply that several polymorphisms detected in the control region of mtDNA may influence physical performance probably in a functional manner.

Simultaneous analysis of dehydroacetic acid, benzoic acid, sorbic acid and salicylic acid in cosmetic products by solid-phase extraction and high-performance liquid chromatography.

A high-performance liquid chromatographic (HPLC) method for simultaneous determination of dehydroacetic acid (DHA), benzoic acid (BA), sorbic acid (SOA) and salicylic acid (SA) was developed for application to cosmetic products. Isocratic reversed-phase HPLC was employed for quantitative analysis using tetra-n-butylammonium (TBA) hydroxide as an ion-pair reagent. Cosmetic samples were purified by solid-phase extraction using Bond-Elut SI cartridges. Four acidic preservatives were eluted with methanol from cartridges. The HPLC assay was carried out using TSK gel ODS-80TM column (5 microm, 150 x 4.6 mm I.D.). The mobile phase consisted of a mixture of water and methanol (65:35, v/v) containing 2.5 mM TBA hydroxide adjusted with phosphoric acid to pH 7.0. The calibration curves of these preservatives showed good linearity with UV detection (235 nm). The correlation coefficients were better than 0.999 in all cases. The lower limits of detection (defined as a signal-to-noise ratio of about 3) were approximately 2.5 ng for DHA, 4.0 ng for BA, 2.0 ng for SOA and 5.5 ng for SA. The procedure described here is simple, selective and is suitable for quality control of finished cosmetic products.

Simultaneous analysis of naproxen, nabumetone and its major metabolite 6-methoxy-2-naphthylacetic acid in pharmaceuticals and human urine by high-performance liquid chromatography.

A high-performance liquid chromatographic (HPLC) method for simultaneous determination of naproxen (NAP), nabumetone (NAB) and its major metabolite, 6-methoxy-2-naphthylacetic acid (6-MNA), was developed for the application to pharmaceuticals and human urine. Isocratic reversed-phase HPLC was employed for quantitative analysis using triethylamine and 1-heptanesulfonic acid sodium salt (HSA) as ion-pair reagents. Urine samples were purified by solid-phase extraction using Bond-Elut Certify II cartridges containing reversed-phase and anion exchange functionalities. The HPLC assay was carried out using a Wakosil ODS 5C18 column (5 microm, 150 x 4.6 mm, i.d.). The mobile phase consisted of 0.5 g of HSA dissolved in 1,000 ml of a mixture of acetonitrile, water and triethylamine (500:500:1, v/v) adjusted with phosphoric acid to pH 3. The calibration curves of NAP and NAB showed good linearity in the concentration range 32-160 microg/ml with UV detection (270 nm) for pharmaceuticals. In the low concentration ranges (8-96 ng of NAP per ml, 24-288 ng of NAB per ml and 5.6-67.2 ng of 6-MNA per ml), the calibration curves were also obtained with fluorimetric detection (excitation 280 nm, emission 350 nm) for biological fluids. The correlation coefficients were better than 0.999 in all cases. The lower limits of detection (defined as a signal-to-noise ratio of about 3) were approximately 0.3 ng for NAP, 1.5 ng for NAB and 0.2 ng for 6-MNA. The procedure described here is rapid, simple, selective, and is suitable for routine analysis of pharmaceuticals and pharmacokinetic studies in human urine samples.

Simultaneous analysis of anthranilic acid derivatives in pharmaceuticals and human urine by high-performance liquid chromatography with isocratic elution.

A high-performance liquid chromatographic (HPLC) method for simultaneous determination of mefenamic acid (MFA), flufenamic acid (FFA) and tolfenamic acid (TFA) is presented for application to pharmaceuticals and human urine. Isocratic reversed-phase HPLC was employed for quantitative analysis using tetra-pentylammonium bromide (TPAB) as an ion-pair reagent. Urine samples were purified by solid-phase extraction using a silica-based strong anion-exchanger, Bond-Elut SAX cartridge. The HPLC assay was carried out using a Wakosil ODS 5C18 column (5 microm, 150x4.6 mm I.D.). The mobile phase consisted of 1.9 g of TPAB dissolved in 1:1 of a mixture of acetic acid-sodium acetate buffer solution, pH 5.0, and acetonitrile (11:9, v/v). The calibration curves of MFA, FFA and TFA showed good linearity in the concentration range of 33-167 microg/ml with a wavelength of 280 nm for pharmaceuticals, and in the low concentration range (1.7-30.1 microg/ml) with a wavelength of 230 nm for biological fluids. The correlation coefficients were better than 0.9999 in all cases. The lower limits of detection (defined as a signal-to-noise ratio of about 3) were approximately 2 ng for MFA, 3.5 ng for FFA and 2.5 ng for TFA. The procedure described here is rapid, simple, selective and is suitable for routine analysis of pharmaceuticals and pharmacokinetic studies in human urine samples.

Characterization of three thermophilic strains of Methanothrix ("Methanosaeta") thermophila sp. nov. and rejection of Methanothrix ("Methanosaeta") thermoacetophila.

Three thermophilic Methanothrix ("Methanosaeta") strains, strains PTT (= DSM 6194T) (T = type strain), CALS-1 (= DSM 3870), and Z-517 (= DSM 4774), were characterized chemotaxonomically and compared with five mesophilic strains, Methanothrix soehngenii ("Methanosaeta concilii") GP6 (= DSM 3671), Opfikon (= DSM 2139), FE (= DSM 3013), UA, and PM. These methanogens were exclusively acetotrophic and had a characteristic sheathed structure. The DNA base compositions of the strains which we studied ranged from 50.3 to 54.3 mol% guanine plus cytosine. The thermophilic strains often had phase-refractive gas vesicles inside their cells. Denaturing electrophoresis of proteins showed that the mesophilic and thermophilic Methanothrix strains formed two distinct groups and that there were differences in protein patterns between the groups. The difference between the thermophiles and mesophiles was also verified by comparing partial 16S rRNA sequences (ca. 30 base differences in ca. 540 bases). On the basis of our results, we propose the name Methanothrix thermophila for the three thermophilic strains. The type strain of M. thermophila is strain PT (= DSM 6194). We also propose that the name Methanothrix thermoacetophila ("Methanosaeta thermoacetophila"), which was given to strain Z-517 (type strain), should be rejected because of its description, which was based on an enrichment culture, was inadequate.

Utilization of methoxylated benzoates and formation of intermediates by Desulfotomaculum thermobenzoicum in the presence or absence of sulfate.

Desulfotomaculum thermobenzoicum strain TSB (DSM 6193) was found to utilize some methoxylated benzoates as carbon and energy source with or without sulfate. 3- or 4-Methoxybenzoate, vanillate (4-hydroxy-3-methoxybenzoate), syringate (3,5-dimethoxy-4-hydroxybenzoate) and 3,4,5-trimethoxybenzoate were converted to corresponding hydroxybenzoates. However, neither 2-methoxybenzoate nor 2,6-dimethoxybenzoate was utilized. The organism grew acetogenically on each of the methoxylated benzoates in the absence of sulfate. 3,4-Dihydroxy-5-methoxybenzoate was detected during conversion of syringate, and syringate and 3,4-dihydroxy-5-methoxybenzoate were detected during conversion of 3,4,5-trimethoxybenzoate as intermediates. These findings indicate that 4-methoxyl-group is most readily cleaved, whereas 2-methoxyl-group is not utilized by the organism.

Removal of methanethiol, dimethyl sulfide, dimethyl disulfide, and hydrogen sulfide from contaminated air by Thiobacillus thioparus TK-m.

Methanethiol, dimethyl sulfide, dimethyl disulfide, and hydrogen sulfide were efficiently removed from contaminated air by Thiobacillus thioparus TK-m and oxidized to sulfate stoichiometrically. More than 99.99% of dimethyl sulfide was removed when the load was less than 4.0 g of dimethyl sulfide per g (dry cell weight) per day.

Analysis of natural coloring matters in food. III. Application of methylation with diazomethane for the detection of lac color.

A new method has been proposed for detection of lac color in food. Lac color is a natural color additive derived from a secretion of the insect Coccus Laccae (Laccifer lacca Kerr). It is extracted from food with methanolic oxalic acid and eluted from a column of Amberlite XAD-2 with the same solvent. The fraction containing the lac color is treated with diazomethane to produce 2 reddish-orange markers. The marker species in the reaction mixture are detected by both thin-layer chromatography and reverse-phase liquid chromatography.

Precursors of globin mRNA in erythroid-enriched bone marrow cells of mouse.

RNA from erythroid-enriched bone marrow cells of mouse was analyzed under two kinds of denaturing conditions (in 99% formamide and formaldehyde treatment), and globin mRNA sequence-containing RNAs larger than 18S in addition to 16S and 10S were detected by hybridization at a comparatively high Rot with complementary DNA (cDNA) to globin mRNA (10S). The existence of precursor RNAs larger than 18S was confirmed by two different methods; (i) recentrifugation in 99% formamide of RNA collected from the corresponding regions of RNA fractions and following detection of globin mRNA sequences, (ii) the specific isolation of [3H]labeled precursor RNA with a cDNA-cellulose column and fractionation in a 99% formamide-sucrose gradient. Furthermore, pulse-chase experiments indicated that some large RNAs with globin mRNA sequences could be chased to 10S RNA during a 30 min chase in the presence of a high concentration of actinomycin D (10 microgram/ml). From the results it was assumed that 35-37S RNAs with globin mRNA sequences were possible primary transcripts of globin genes and other RNAs with globin mRNA sequences in 16S, 20S, and 26S regions were intermediate precursors of 10S globin mRNA.

Changes of ion mobilizations and their related enzyme activities in the blood of fluoride-intoxicated rats.

Fluoride concentrations in plasma 3 hr after a single oral dose of NaF (5 mg/100 g body weight) were increased 26 times above the control, but the concentrations in erythrocytes and red cell membranes were increased only 1.8 and 1.5 times over the respective control levels. Ionic concentrations of magnesium and calcium in erythrocytes and their membranes were significantly changed by fluoride administration, but the ionic concentrations in plasma were not statistically changed in comparison with controls. Acid phosphatase activities in plasma and erythrocytes were significantly decreased by fluoride administration, but alkaline phosphatase activity in the plasma was not changed. Mg2+-activated ATPase activity was significantly elevated in the erythrocyte membrane by fluoride administration; (Na+ + K+)-activated ATPase activity was significantly decreased in the membrane.