Blood glucose responses in humans mirror lactate responses for individual anaerobic threshold and for lactate minimum in track tests

The equilibrium point between blood lactate production and removal (La-(min)) and the individual anaerobic threshold (IAT) protocols have been used to evaluate exercise. During progressive exercise, blood lactate [La-]b, catecholamine and cortisol concentrations, show exponential increases at upper anaerobic threshold intensities. Since these hormones enhance blood glucose concentrations [Glc]b, this study investigated the [Glc] and [La-]b responses during incremental tests and the possibility of considering the individual glucose threshold (IGT) and glucose minimum (Glc(min)) in addition to IAT and La-(min) in evaluating exercise. A group of 15 male endurance runners ran in four tests on the track 3000 m run (v3km); IAT and IGT - 8 x 800 m runs at velocities between 84% and 102% of v3km; La-(min) and Glc(min) - after lactic acidosis induced by a 500-m sprint, the subjects ran 6 x 800 m at intensities between 87% and 97% of v3km; endurance test (ET) - 30 min at the velocity of IAT. Capillary blood (25 microl) was collected for [La-]b and [Glc]b measurements. The IAT and IGT were determined by [La-]b and [Glc]b kinetics during the second test. The La-(min) and Glc(min) were determined considering the lowest [La-] and [Glc]b during the third test. No differences were observed (P < 0.05) and high correlations were obtained between the velocities at IAT [283 (SD 19) and IGT 281 (SD 21) m. x min(-1); r = 0.096; P < 0.001] and between La-(min) [285 (SD 21)] and Glc(min) [287 (SD 20) m. x min(-1) r = 0.77; P < 0.05]. During ET, the [La-]b reached 5.0 (SD 1.1) and 5.3 (SD 1.0) mmol x l(-1) at 20 and 30 min, respectively (P > 0.05). We concluded that for these subjects it was possible to evaluate the aerobic capacity by IGT and Glc(min) as well as by IAT and La-(min).     

A possibility of systematisation of anthropometric data of girls aged 12-15

The article describes an anthropometric cross-sectional study of 374 healthy schoolgirls aged 12-15 years from secondary schools of Tartu (Estonia). 29 body measurements and 9 skinfolds were measured. Mean skinfolds and 6 indices and ratios (including body mass index) were calculated. In each age group the data were systematized into 5 height-weight SD-classes according to the correspondence between body height and weight. The medium class lies between -0.5 SD and +0.5 SD of the respective age group mean (M +/- 0.5 SD); the other classes contain the respective outer values. All the subjects were assigned into one of the following five categories: three height/weight-concordant categories: I = small (small height-small weight), II = medium (medium height-medium weight), III = large (big height-big weight) and two height/weight-disconcordant categories: IV = so-called pyknomorphous, V = so-called leptomorphous. Categories IV and V thus contained three height/weight subclasses each. The body build categories differ significantly from each other within both groups (I-III and IV-V) in all age groups in all measured variables, except sternum length, abdomen length, trunk length, biacromial breadth, biiliocrystal breadth, femur breadth, ankle breadth, humerus breadth, wrist breadth, and head circumference for which no significant differences between pyknomorphous and leptomorphous categories were found. A multidimensional statistical model of body build might be used in girls going through puberty to systematize and compare morphological variables with other assessed characteristics in different applied studies, for example physiological, sociological, psychological, or nutritional.     

Evolution of nutritional modes of Ceratobasidiaceae (Cantharellales,Basidiomycota) as revealed from publicly available ITS sequences

Fungi from the Ceratobasidiaceae family have important ecological roles as pathogens, saprotrophs, non-mycorrhizal endophytes, orchid mycorrhizal and ectomycorrhizal symbionts, but little is known about the distribution and evolution of these nutritional modes. All public ITS sequences of Ceratobasidiaceae were downloaded from databases, annotated with ecological and taxonomic metadata, and tested for the non-random phylogenetic distribution of nutritional modes. Phylogenetic analysis revealed six main clades within Ceratobasidiaceae and a poor correlation between molecular phylogeny and morphological–cytological characters traditionally used for taxonomy. Sequences derived from soil (representing putative saprotrophs) and orchid mycorrhiza clustered together, but remained distinct from pathogens. All nutritional modes were phylogenetically conserved in the Ceratobasidiaceae based on at least one index. Our analyses suggest that in general, autotrophic orchids form root symbiosis with available Ceratobasidiaceae isolates in soil. Ectomycorrhiza-forming capability has evolved twice within the Ceratobasidiaceae and it had a strong influence on the evolution of mycoheterotrophy and host specificity in certain orchid taxa.     

SLC2A9 is a high-capacity urate transporter in humans

Background

Serum uric acid levels in humans are influenced by diet, cellular breakdown, and renal elimination, and correlate with blood pressure, metabolic syndrome, diabetes, gout, and cardiovascular disease. Recent genome-wide association scans have found common genetic variants of SLC2A9 to be associated with increased serum urate level and gout. The SLC2A9 gene encodes a facilitative glucose transporter, and it has two splice variants that are highly expressed in the proximal nephron, a key site for urate handling in the kidney. We investigated whether SLC2A9 is a functional urate transporter that contributes to the longstanding association between urate and blood pressure in man.

Methods and Findings

We expressed both SLC2A9 splice variants in Xenopus laevis oocytes and found both isoforms mediate rapid urate fluxes at concentration ranges similar to physiological serum levels (200–500 μM). Because SLC2A9 is a known facilitative glucose transporter, we also tested whether glucose or fructose influenced urate transport. We found that urate is transported by SLC2A9 at rates 45- to 60-fold faster than glucose, and demonstrated that SLC2A9-mediated urate transport is facilitated by glucose and, to a lesser extent, fructose. In addition, transport is inhibited by the uricosuric benzbromarone in a dose-dependent manner (K _i = 27 μM). Furthermore, we found urate uptake was at least 2-fold greater in human embryonic kidney (HEK) cells overexpressing SLC2A9 splice variants than nontransfected kidney cells. To confirm that our findings were due to SLC2A9, and not another urate transporter, we showed that urate transport was diminished by SLC2A9-targeted siRNA in a second mammalian cell line. In a cohort of men we showed that genetic variants of SLC2A9 are associated with reduced urinary urate clearance, which fits with common variation at SLC2A9 leading to increased serum urate. We found no evidence of association with hypertension (odds ratio 0.98, 95% confidence interval [CI] 0.9 to 1.05, p > 0.33) by meta-analysis of an SLC2A9 variant in six case–control studies including 11,897 participants. In a separate meta-analysis of four population studies including 11,629 participants we found no association of SLC2A9 with systolic (effect size −0.12 mm Hg, 95% CI −0.68 to 0.43, p = 0.664) or diastolic blood pressure (effect size −0.03 mm Hg, 95% CI −0.39 to 0.31, p = 0.82).

Conclusions

This study provides evidence that SLC2A9 splice variants act as high-capacity urate transporters and is one of the first functional characterisations of findings from genome-wide association scans. We did not find an association of the SLC2A9 gene with blood pressure in this study. Our findings suggest potential pathogenic mechanisms that could offer a new drug target for gout.     

On polynuclear aromatic hydrocarbons contamination levels in the ecosystem of Lake Peipsi in the 1970s–1980s

The data on benzo(a)pyrene (BaP) and other polynuclear aromatic hydrocarbons (PAH) pollution of Lake Peipsi and its tributaries in the 1970s–1980s have been summarized. Systematic data on the pollution of Lake Peipsi by BaP are available. The BaP content in lake water varied from <0.1 to 237 ng 1^–1. The content and qualitative composition of PAH varied in different observations. PAH were accumulated mainly in the bottom sediments; in their surface layer BaP concentrations were 10³–10⁶ times higher than in water. The concentration of the PAH in bottom sediments varied from 16 to 580 µg kg^–1 in the lake and from 40 to 2800 µg kg^–1 in its tributaries. The content of BaP in fish and biota was not high. Among the pollution sources the atmospheric pollution played quite a significant role. The lake was also polluted by oil spillage and fuel exhausts from boats and ships. The PAH concentration in the water of the tributaries was somewhat higher than in the area of Lake Peipsi.     

Anthropometric parameters and sexual maturation in 12- to 15-year-old Estonian boys

The aims of this study were 1. to fix main sexual maturation signs and anthropometric measurements, and 2. to investigate relations between maturational status and main anthropometric parameters (i.e. skinfolds, girths, lengths, breadths/lengths) in 12-15-year old boys. In total, 361 boys from Tartu, Estonia, were studied. Body height and weight, 9 skinfolds, 13 girths, 8 lengths and 8 breadths/lengths were measured. Pubertal stages were determined according to the criteria described by Tanner (1962). Self-assessment of pubic hair (PH1-PH5) was used. Genital development (G1-G5) was estimated by palpating the left testis and matching the size of wood ovoid of the Prader orchidometer. Finally, boys were asked about oigarche (= age at the first ejaculation of sperm). Most of the measured anthropometric variables were significantly different in boys of different chronological age and sexual maturity groups. By linear discriminant analysis, the safety of separation of the chronological age groups was higher than by sexual maturation variables. Nonlinear discriminant analysis allowed to separate sexual maturity groups by anthropometric variables up to 99% security. It was concluded that though the growth and development of a child is highly individual, on an average the anthropometric characteristics alter very constantly with the increase of age and biological maturation. Our results indicated that there were some significant differences in the anthropometrical parameters depending on the chronological age and biological maturation. Mostly length and breadth/length parameters change during the studied age period in respect to sexual development subgroups of boys. The skinfold thicknesses were not changed or even decreased.     

An open source chimera checker for the fungal ITS region

The internal transcribed spacer (ITS) region of the nuclear ribosomal repeat unit holds a central position in the pursuit of the taxonomic affiliation of fungi recovered through environmental sampling. Newly generated fungal ITS sequences are typically compared against the International Nucleotide Sequence Databases for a species or genus name using the sequence similarity software suite blast . Such searches are not without complications however, and one of them is the presence of chimeric entries among the query or reference sequences. Chimeras are artificial sequences, generated unintentionally during the polymerase chain reaction step, that feature sequence data from two (or possibly more) distinct species. Available software solutions for chimera control do not readily target the fungal ITS region, but the present study introduces a blast -based open source software package (available at http://www.emerencia.org/chimerachecker.html ) to examine newly generated fungal ITS sequences for the presence of potentially chimeric elements in batch mode. We used the software package on a random set of 12 300 environmental fungal ITS sequences in the public sequence databases and found 1.5% of the entries to be chimeric at the ordinal level after manual verification of the results. The proportion of chimeras in the sequence databases can be hypothesized to increase as emerging sequencing technologies drawing from pooled DNA samples are becoming important tools in molecular ecology research.     

Metabolism, Intake, and Digestibility of Lambs Supplemented with Organic Chromium

The aim of the present study was to evaluate the metabolism of organic chromium and its effect on digestibility and intake of lambs. Four 4-month-old male lambs, each weighing 28 kg, were used. The animals were kept in metabolic cages for a period of 20 days (15 days of adaptation and 5 days of experimentation), in two experimental phases, with inverted treatments. Organic chromium was administered by intraruminal infusion of 1 mg of chromium-rich yeast (Saccharomyces cerevisiae) throughout the adaptive and experimental period. The dry material rates of the diet and feces of the animals were evaluated to estimate consumption, digestibility, and fecal production. During the experimental period, blood, feces, and urine were collected every 24 h to determine chromium levels. There was no significant difference in the excretion of chromium in the urine, and no mineral remnants were detected in the blood. Excretion was generally fecal. There was greater excretion of chromium in the feces of lambs in the treated group on day 0 and day 3, compared with the control group. The use of organic chromium promoted an increase in the consumption of dry material in the treated animals only at day 0 (P?<?0.05). The production of fecal dry matter was greater among the treated lambs than among the animals of the control group on day 1, day 2, day 3, and day 4 (P?<?0.05). The results obtained showed that organic chromium associated with live yeasts is not absorbed by the body and do not affect the intake time in the dose used.