Vitellogenesis as a biomarker for estrogenic contamination of the aquatic environment

A rapidly increasing number of chemicals, or their degradation products, are being recognized as possessing estrogenic activity, albeit usually weak. We have found that effluent from sewage treatment works contains a chemical, or mixture of chemicals, that induces vitellogenin synthesis in male fish maintained in the effluent, thus indicating that the effluent is estrogenic. The effect was extremely pronounced and occurred at all sewage treatment works tested. The nature of the chemical or chemicals causing the effect is presently not known. However, we have tested a number of chemicals known to be estrogenic to mammals and have shown that they are also estrogenic to fish; that is, no species specificity was apparent. Many of these weakly estrogenic chemicals are known to be present in effluents. Further, a mixture of different estrogenic chemicals was considerably more potent than each of the chemicals when tested individually, suggesting that enhanced effects could occur when fish are exposed simultaneously to various estrogenic chemicals (as is likely to occur in rivers receiving effluent). Subsequent work should determine whether exposure to these chemicals at the concentrations present in the environment leads to any deleterious physiological effects

Duodenal-Jejunal Bypass and Jejunectomy Improve Insulin Sensitivity in Goto-Kakizaki Diabetic Rats Without Changes in Incretins or Insulin Secretion

Gastric bypass surgery can dramatically improve type 2 diabetes. It has been hypothesized that by excluding duodenum and jejunum from nutrient transit, this procedure may reduce putative signals from the proximal intestine that negatively influence insulin sensitivity ( S I ). To test this hypothesis, resection or bypass of different intestinal segments were performed in diabetic Goto-Kakizaki and Wistar rats. Rats were randomly assigned to five groups: duodenal-jejunal bypass (DJB), jejunal resection (jejunectomy), ileal resection (ileectomy), pair-fed sham-operated, and nonoperated controls. Oral glucose tolerance test was performed within 2 weeks after surgery. Baseline and poststimulation levels of glucose, insulin, glucagon-like peptide 1 (GLP-1), and glucose-dependent insulinotropic polypeptide (GIP) were measured. Minimal model analysis was used to assess S I . S I improved after DJB ( S I = 1.14 ± 0.32 × 10 −4 min −1 ⋅ pM −1 ) and jejunectomy ( S I = 0.80 ± 0.14 × 10 −4 min −1 ⋅ pM −1 ), but not after ileectomy or sham operation/pair feeding in diabetic rats. Both DJB and jejunal resection normalized S I in diabetic rats as shown by S I levels equivalent to those of Wistar rats ( S I = 1.01 ± 0.06 × 10 −4 min −1 ⋅ pM −1 ; P = NS). Glucose effectiveness did not change after operations in any group. While ileectomy increased plasma GIP levels, no changes in GIP or GLP-1 were observed after DJB and jejunectomy. These findings support the hypothesis that anatomic alterations of the proximal small bowel may reduce factors associated with negative influence on S I , therefore contributing to the control of diabetes after gastric bypass surgery

Rhizobial characterization in revegetated areas after bauxite mining.

Little is known regarding how the increased diversity of nitrogen-fixing bacteria contributesto the productivity and diversity of plants in complex communities. However, some authorshave shown that the presence of a diverse group of nodulating bacteria is required for dif-ferent plant species to coexist. A better understanding of the plant symbiotic organismdiversity role in natural ecosystems can be extremely useful to define recovery strategies ofenvironments that were degraded by human activities. This study used ARDRA, BOX-PCRfingerprinting and sequencing of the 16S rDNA gene to assess the diversity of root nodulenitrogen-fixing bacteria in former bauxite mining areas that were replanted in 1981, 1985,1993, 1998, 2004 and 2006 and in a native forest. Among the 12 isolates for which the 16SrDNA gene was partially sequenced, eight, three and one isolate(s) presented similarity withsequences of the genera Bradyrhizobium, Rhizobium and Mesorhizobium, respectively. The rich-ness, Shannon and evenness indices were the highest in the area that was replanted theearliest (1981) and the lowest in the area that was replanted most recently (2006)

Arbuscular mycorrhizal fungi diversity in revegetated areas after bauxite mining.

Arbuscular mycorrhizal fungi (AMF) are obligatory biotrophs that have a symbiotic evolutionary relationship with about 80% of all terrestrial plant species. The fungus mainly supplies water and nutrients to the plant and receives photoassimilates. The AMF diversity affects both the competition among species and floristic composition of an area. Fluctuations in the population of this group of microorganisms can cause fluctuations in plant populations above ground. In this work, the AMF community profile in areas with different ages of revegetation was evaluated by morphological identification of spores and denaturing gradient gel electrophoresis (DGGE) techniques. We found 12 AMF species and dominance of the species Glomus macrocarpum determined by spore density. Since the richness level observed in each plot was low and there was predominance of one species of AMF, it can be concluded that these areas still present a high degree of disturbance. It was possible to detect complex band profiles by DGGE analyses for the two plant species studied, Visnia latifolia and Cecropia hololeuca. No relationship between AMF diversity and revegetation time was observed in these areas

Investigation of size effects on the structure of liquid GeSe2 calculated via first-principles molecular dynamics

The structural properties of liquid GeSe2 have been calculated by first-principles molecular dynamics by using a periodic simulation box containing N = 480 atoms. This has allowed a comparison with previous results obtained on a smaller system size (N = 120) [M. Micoulaut, R. Vuilleumier, and C. Massobrio, Phys. Rev. B 79, 214205 (2009)]. In the domain of first-principles molecular dynamics, we obtain an assessment of system size effects of unprecedented quality. Overall, no drastic differences are found between the two sets of results, confirming that N = 120 is a suitable size to achieve a realistic description of this prototypical disordered network. However, for N = 480, short range properties are characterized by an increase of chemical order, the number of Ge tetrahedra coordinated to four Se atoms being larger. At the intermediate range order level, size effect mostly modify the low wavevector region (k similar to 1 angstrom(-1)) in the concentration-concentration partial structure factor

Do South African international cricket pace bowlers have similar bowling volume and injury risk associates compared to other elite fast bowlers?

BACKGROUND While many cricket-playing nations have conducted research on bowling volume (BV) and injury risk, this relationship among international South African pace bowlers is yet to be investigated. Environmental, socio-economic, and training strategy differences warrant similar research in a South African context. The purpose of this preliminary study was to establish if South African pace bowlers have similar bowling volume and injury associates compared to other elite fast bowlers. METHODS This study was a prospective, observational, cohort study that monitored match and training BV and injuries among pace bowlers playing for the South African national team between April 2017 and April 2019. A sample of convenience that included fourteen bowlers was selected. Bowling volume was quantified as the number of deliveries bowled during training and competition. Acute-, chronic- and acute: chronic bowling volume ratios were independently modeled as association variables. RESULTS There were 39 injuries with the most being to the lumbar spine (25.64%). Moderate-to-low and a moderate-to-high acute: chronic bowling load ratios were associated with a lower risk of injury. Chronic bowling load was associated with injury (z = 2.82, p = 0.01). A low acute workload, low chronic workload, moderate-high chronic workload, and moderate-low acute: chronic ratio was also associated with an increased risk of injury. CONCLUSION These findings confirm that there appears to be a dose-response effect between training bowling volume and the likelihood of an injury occurring with a moderate-to-low and a moderate-to-high bowling volume ratio being optimal. Considering the small sample size, the findings should be interpreted with caution

Meson Decays In A Quark Model

A recent model of hadron states is extended to include meson decays. We find that the overall success of the model is quite good. Possible improvements to the model are suggested.Comment: 13 pages, RevTeX. 2 postscript figures, uses eps

Structural properties of glassy Ge2Se3 from first-principles molecular dynamics

The structural properties of glassy Ge2Se3 were studied in the framework of first-principles molecular dynamics by using the Becke-Lee-Yang-Parr scheme for the treatment of the exchange-correlation functional in density functional theory. Our results for the total neutron structure factor and the total pair distribution function are in very good agreement with the experimental results. When compared to the structural description obtained for liquid Ge2Se3, glassy Ge2Se3 is found to be characterized by a larger percentage of fourfold coordinated Ge atoms and a lower number of miscoordinations. However, Ge-Ge homopolar bonds inevitably occur due to the lack of Se atoms available, at this concentration, to form GeSe4 tetrahedra. Focusing on the family of glasses GexSe1-x, the present results allow a comparison to be carried out in reciprocal and real space among three prototypical glassy structures. The first was obtained at the stoichiometric composition (glassy GeSe2), the second at a Se-rich composition (glassy GeSe4) and the third at a Ge-rich composition (glassy Ge2Se3). All networks are consistent with the “8 - N” rule, in particular, glassy GeSe4, which exhibits the highest degree of chemical order. The electronic structure of glassy Ge2Se3 has been characterized by using the Wannier localized orbital formalism. The analysis of the Ge environment shows the presence of dangling, ionocovalent Ge-Se, and covalent bonds, the latter related to Ge-Ge connections. DOI: 10.1103/PhysRevB.86.224201This work was granted access by GENCI (Grand Equipement National de Calcul Intensif) under allocation 2011095071 to the HPC resources of CCRT/CINES/IDRI

The structure of liquid GeSe revisited: A first principles molecular dynamics study:

Early first-principles molecular dynamics results on liquid GeSe were characterized by shortcomings in the description of Ge-Ge (and to a lesser extent Se-Se) short range correlations. In that case the exchange-correlation functional adopted was the one devised by Perdew and Wang (PW91). In the search of improvements in the atomic-scale modelling of this liquid, we have produced new sets of data by employing two different schemes for the exchange-correlation part within the density functional theory approach. The two functionals selected are those proposed by Becke, Lee, Yang, and Parr (BLYP) and by Perdew, Burke, and Ernzerhof (PBE). The PBE results turned out to be quite similar to the PW91 ones. The BLYP results feature instead a better account of the Ge-Ge first shell of neighbors, correctly exhibiting two clear maxima separated by a deep minimum. Due to the increase in the number of the tetrahedral structural units, the atomic mobility of Ge and Se atoms in the network is reduced with respect to the PW91 case. This brings the diffusion coefficients of the two species down to values close to those of liquid Ge2Se3 and liquid GeSe2. (C) 2013 AIP Publishing LLC