It is likely that heterozygotes inheriting the Val236 variant subunit would have a partial deficiency of GSTO1-1 activity. Despite their effects on enzyme function the known variants of GSTO1-1 do not appear to explain the observed variability in the excretion of inorganic arsenic.

No abstract

There are many studies documenting the genotoxic effects of environmental exposure to arsenic. Nevertheless, few data are available on the genotoxic risks of occupational arsenic exposure. In the present study, we have evaluated whether or not occupational exposure to arsenic in a copper smelting plant results in a significant increase in the frequency of sister chromatid exchange (SCE). SCE frequencies, proliferation rate index (PRI), and high frequency cells (HFCs) were evaluated in peripheral blood lymphocytes from a group of 105 arsenic-exposed workers from a Chilean smelting plant (exposed group). Similar assays were conducted on a group of 55 workers employed at the same mine but involved in administrative jobs (internal control), and on 48 workers of another mine, with no significant levels of arsenic (external control). Small but significant increases in SCE frequency were observed in the arsenic-exposed workers compared with the external control group (6.28+/-0.09 vs. 5.84+/-0.14 SCE/cell; P<0.01). Also, significantly higher frequencies of HFCs were observed in the exposed group (2.21%+/-0.20%) than in either the external control group (1.20+/-0.23; P=0.002) or the internal control group (1.30+/-0.24; P=0.008). However, there was no relationship between arsenic levels in the urine of the subjects and SCE or HFC frequency. The results of the study indicate that copper smelting results in slightly increased levels of DNA damage. However, our data were not consistent with arsenic exposure being the cause of the increase.

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In Brazil, most sheep are of the Santa Inês breed, which shows rusticity in breeding and grazing systems, being able to offer better adaptation characteristics for animals with meat production ability, such as the Texel and Dorper sheep. They can also improve meat production in animals that have better characteristics for milk production, such as Lacaune and East Friesian breeds. We investigated the polymorphisms of calpastatin (CAST) and myostatin (GDF8) genes and their association with meat quality parameters of 84 lambs, including: 14 purebred Santa Inês and 70 crossbred animals of five genetic groups: 16 animals (½ Santa Inês x ½ Black Dorper); 12 animals (½ Santa Inês x ½ White Dorper); 19 animals (½ Santa Inês x ½ Texel); 14 animals (½ Santa Inês x ½ Lacaune); and 9 animals (½ Santa Inês x ½ East Friesian). To evaluate the polymorphism of the genes we used PCR and Simple Chain Conformation Polymorphism (SSCP) with DNA sequencing to determine where base exchange occurred in the gene sequences. The PCR-SSCP technique detected four bands of the CAST gene and three of the GDF-8 gene. In meat quality of sheep there was ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 19 (3): gmr18325 C. Esteves et al. 2 only one different breed group by Shear force with less value than Santa Ines breed group. The CAST gene had four genotypes with two single nucleotide polymorphisms (SNPs) (c.679A> G; c.383A> G), which resulted in the exchange of glutamic acid by glycine and threonine by alanine, which impacted pH values. Reduced pH values for BB and AB genotypes, and increased pH value in the AA genotype were found. Three genotypes of the DGF-8 gene with three SNPs were identified with changes of AT , A-G, and T-G, influencing color hue angle (h*). After 10 days post mortem, there was an increase in hue angle the highest values were found for genotypes DF and DE. The polymorphisms of the CAST gene and in the promoter region of the GDF-8 gene influence meat color and final pH, affecting meat quality in various of the sheep breed groups.

Arsenic is a world health problem due to the seriousness of its effects, mainly related with the increase of cancer. In Chile, the geological characteristics of the northern region, associated with the development of the copper mining and smelting activities, have contributed to increase the environmental levels of arsenic. This study has been conducted to investigate the relationship between arsenic occupational exposure and genotoxic effects in smelting plant workers. To determine the genotoxic risk related to the increase of cancer among the chronically exposed population, the frequency of micronuclei in blood (BNMN) has been evaluated. The study was carried out in a total of 207 men, divided into three groups: an exposed group of 105 individuals working in a smelting plant, an internal reference group with 52 employees at the same mine but in the administrative area, and an external reference group of 50 workers from another copper mine where no significant levels of arsenic were detected. As expected, differences between arsenic levels in urine have been detected between groups, with the exposed group being the one with a higher level of total arsenic in urine, followed by the internal reference group. Despite that, no significant differences in micronuclei frequencies in lymphocytes were detected among these groups.