Photooxidation products of 7,12-dimethylbenz[a]anthracene.

The principal products of the photooxidation of 7,12-dimethylbenz[a]-anthracene (DMBA) in aqueous solutions by photooxidation induced by laboratory lighting have been characterized by high performance liquid chromatograms (HPLC), ultraviolet and mass spectrograms and by comparisons with authentic samples. The products identified were the 7,12-epidioxy-7,12-dihydro-7-12-dimethyl-, 7,12-dione, 7-hydroxymethyl-12-methyl-, 12-hydroxymethyl-7-methyl-, 7-formyl-12-methyl-, 12-formyl-7-methyl-, and 12-hydroxy-12-methyl-7-one derivatives of benz[a]-anthracene. The HPLC profile of products is similar to that obtained from oxidation of DMBA by 'one-electron' reagents, singlet oxygen, or liver microsomal metabolism. The first points of attack are the 7- and 12- positions. The mechanism of photooxidation appears to be generation of singlet oxygen by photodynamic effect of DMBA. None of the products is photosensitizing, however.     

Effects of feeding transgenic corn with mCry1Ac or maroACC gene to laying hens for 12 weeks on growth,egg quality and organ health

The objective of the present study was to investigate the effect of feeding two transgenic corn lines containing the mCry1Ac gene from Bacillus thuringiensis strain (BT-799) and the maroACC gene from Agrobacterium tumefaciens strain (CC-2), respectively, on growth, egg quality and organ health indicators. Expression of the mCry1Ac gene confers resistance to Pyrausta nubilalis and the maroACC gene confers tolerance to herbicides. Healthy hens (n=96 placed in cages; 3 hens/cage) were randomly assigned to one of four corn–soybean meal dietary treatments (8 cages/treatment) formulated with the following corn: non-transgenic near-isoline control corn (control), BT-799 corn, CC-2 corn and commercially available non-transgenic reference corn (reference). The experiment was divided into three 4-week phases (week 1 to 4, week 5 to 8 and week 9 to 12), during which hens were fed mash diets. Performance (BW, feed intake and egg production) and egg quality were determined. Following slaughter at the end of 12 weeks of feeding (n=8/treatment), carcass yield and organ weights (heart, liver, spleen, lung, kidneys, stomach and ovary) were recorded; organs and intestines were sampled for histological analysis. Analysis of serum biochemistry parameters to assess the liver and kidney function were performed. No differences in BW, egg production and production efficiency were observed between hens consuming the control diet and hens consuming the BT-799 or CC-2 diet. Haugh unit measures and egg component weights were similar between the control and test groups. Carcass yield was not affected by the diet treatment. Similar organosomatic indices and serum parameters did not indicate the characteristics of organ dysfunction. All observed values of the BT-799 and CC-2 groups were within the calculated tolerance intervals. This research indicates that the performance, egg quality, organ health and carcass yield of laying hens fed diets containing the BT-799 or CC-2 corn line were similar to that of laying hens fed diets formulated with the non-transgenic near-isoline corn with comparable genetic backgrounds.     

Enhanced ozone exposure of European beech (Fagus sylvatica) stimulates nitrogen mobilization from leaf litter and nitrogen accumulation in the soil

Abstract

In a lysimeter study with young beech trees, the effects of elevated ozone concentration on the decomposition and fate of nitrogen in ¹⁵N‐labeled leaf litter were analyzed after one growing season. Nitrogen in the litter was dominated by a relatively inert, residual fraction, but easily decomposable nitrogen was present in substantial amounts. Nitrogen loss was significantly higher at twice‐ambient ozone which was largely attributed to an enhanced mobilization of residual nitrogen. Enhanced mobilization of nitrogen from litter at twice‐ambient ozone exposure resulted in additional ¹⁵N incorporation into the soil down to 30 cm depth. Only 0.41–0.62% of the nitrogen in the litter was incorporated into plant material at both ozone concentrations. Twice‐ambient ozone exposure changed the distribution of the nitrogen taken up from litter inside the beech trees in favor of the shoot, where it may have been used in biosynthetic processes required for defense reactions.     

Reaction of forest soil microflora to environmental stress along a moderate pollution gradient next to an oil refinery

Twenty-five study sites were established along a 57-km-long transect in order to estimate the impact of an oil refinery, mainly emitting sulphur dioxide (24000 t yr⁻¹), on forest soil (F/H-horizon) chemistry and microbiology. The study demonstrated the existence of a pollution gradient which was best represented by the logarithm of the concentration of vanadium in the analyzed F/H soil layer. Of the soil microbial characteristics measured, including length of fungal hyphae, soil respiration, microbial biomass C and N, and percentage mass loss of Scots pine (Pinus sylvestris) needle litter, only fungal hyphal length was suppressed by the pollution load. No reduction in basic cations (Ca, Mg, K, and Na) in the F/H-horizon, or enrichment of soluble aluminum in the F/H-horizon of the Scots pine forest could be detected to result from the deposition.     

Somatotype and physical performance in a sample of university students from Madrid

A sample of 303 Madrid Complutense University students (100 males and 203 females), aged 21–29 years has been studied in order to establish the relationship between somatotype components and physical work performance. Since particular interest is focused on a possible sexual difference in that relationship, males and females were analyzed separately. Results prove the high correlation of test scores implying muscularity (hand grips, pulling strength) with the mesomorphic component of the somatotype, mainly in males. Variability in tests relative to physical totype, mainly in males. Variability in tests relative to physical fitness is mainly explained by differences in endomorphy, although regarding the step test, ectomorphy is also a factor to be taken into account in females, as well as the pulling strength in males.