Determination of Fitness Components of Flies Bearing the Recessive Lethal l(2)M167DTS Mutation with Dominant Heat Sensitivity in Artificial Drosophila melanogaster Populations

Elimination of the heat-sensitive l(2)M167 ^DTS mutation from artificial Drosophila melanogaster populations at constant temperature 25°C and various frequencies of the mutation in the parental generation was studied. Components of fitness of the l(2)M167 ^DTS mutation were estimated in the artificial populations by means of the recurrent model of the dependence of the frequency of this mutation in a given generation on its frequency in the previous generation. The model was solved by a numerical method with limitations on the values of some fitness components obtained in test experiments. According to the limitations and frequencies of the l(2)M167 ^DTS mutation, the leading role and limits of the variation in egg-to-adult viability and female fertility were determined. The previously suggested effect of the positive selection for viability of individuals heterozygous for l(2)M167 ^DTS was confirmed.__________Translated from Genetika, Vol. 41, No. 6, 2005, pp. 767–777.Original Russian Text Copyright © 2005 by Kulikov, Kuznetsov, Marec, Mitrofanov.     

Carbon and Nitrogen Mineralization of Lead Treated Soils in the Eastern Mediterranean Region,Turkey

The aim of this study was to determine the first effect of lead on microbial activity in soil. The study was carried out in the soil samples from four different radish (Raphanus sativus L. var. radicula, Brassicaceae) fields along the highway in a district (Kadirli, Osmaniye) of the Eastern Mediterranean Region, Turkey. After the calculation of Pb contents, the Pb amounts of the soil samples were brought up to 50 and 100 mg Pb kg^?1 by treatment with Pb(NO ₃ ) ₂ , and the samples for the carbon and the nitrogen mineralization were incubated under controlled conditions (28°C, constant moist). The carbon mineralization was determined by a CO ₂ respiration method for 30 days. The nitrogen mineralization was observed in vitro for 6 weeks. The untreated group was statistically different from the 50 and 100 mg Pb kg^?1 treatments in the aspect of the C(CO ₂ ) outlet during mineralization (P ≤ 0.05), but difference between the 50 and 100 mg Pb kg^?1 treatments was not significant. NH ₄ -N and NO ₃ -N contents of each soil were shown differences between across treatments. Based on these results, it is possible to conclude that the addition of 50 and 100 mg Pb kg^?1 provided a toxic effect threshold for the microbial activity into 30 days.     

Morphometric Analysis of Male Genitalia in Sibling Species of Drosophila virilis Sturt.

The structure of male genital organs in sibling species of the virilis group of Drosophila was examined using methods of multivariate statistics. The differences among these species were estimated using 33 indices and 2 angle parameters. The intraspecific and interspecific correlation structure of the examined characters and the order of their divergence were established. The key characters with respect to forming interspecific differences in the virilis species group were identified. Based on these results, the relative systematic positions of the sibling species are discussed as well as similarities and differences of the pattern of relationships among the species from that generally accepted for the virilis group.     

Incidence of mycoflora and mycotoxins in some edible fruits and seeds of forest origin

Twelve fungi namelyAlternaria alternata, Aspergillus flavus, A niger, A ochraceus, Actinomucor repens, Capnodoium spp., Curvularia lunata, Fusarium pallidoroseum, F solani, F verticillioides, Penicillium citrinum and Rhizopus stolonifer were recorded from samples ofAegle marmelos, Aesculus indica, Buchanania lanzan andPinus gerardiana. In case ofPrunus amygdalus only Rstolonifer was recorded. A significant variation in pattern of mycoflora incidence was observed in terms of source and season. Fungal infestation in most of the substrates was found to be highest during monsoon. Aflatoxins were the most common mycotoxins elaborated by different isolates ofA flavus obtained fromA marmelos, B lanzan andP gerardiana. The amount of aflatoxins produced by the toxigenic isolates ofA flavus was in the range of traces to 0.9–26.0 μg/ml inA marmelos, 0.8–17.5 μg/ml inP gerardiana and 0.65–13.2 μg/ml inB lanzan. The percentage toxigenicity was comparatively lower in the isolates of other mycotoxigenic fungi. Aflatoxins were detected almost in all the samples analyzed for mycotoxin contamination. However, traces of zearalenone were detected inA marmelos. The concentration of aflatoxin B₁ was in the range of 0.13–0.75 μg/g inA marmelos, 0.09–0.60 μg/g inP gerardiana and 0.01–0.20 ug/g inB lanzan. Mycotoxins were not detected inAesculus indica andPrunus amygdalus.     

The Percentage of Cytoskeleton-Bound Polysomes as Affected by the Physiological Condition of Plant Cells

The effects of illumination, temperature, deficiency of water or oxygen, phytohormones, and seedling age on the proportion of cytoskeleton-bound polysomes (CBP) in plant tissues were studied. This proportion was shown to vary depending on factors affecting protein synthesis: it decreased under the influence of factors inhibiting protein synthesis and reducing the relative content of polysomes in tissues (oxygen and water deficiencies, seedling aging) and vice versaincreased under the influence of the factors promoting translation (cytokinin, light). The significance of reversible polysome attachment to the cytoskeleton as a mechanism controlling protein synthesis is discussed.     

The effect of acetylcholine on shifts in the spatial synchronization of the cortical potentials in the rabbit evoked by the reversible interruption of the mammillary body connections

To study the role of cholinergic transmitter system in the maintenance of sychronizing limbic influences, the dynamics of the spatial distribution of the changes of cross-correlation coefficients of rabbits EEG led by 24 electrodes, was estimated at application of acetylcholine solution to the visual cortical area in combination with anode polarization of mammillary bodies. Acetylcholine, which separate effect was connected with a restricted increase of the spatial synchronization of potentials, completely eliminated the effects of isolated polarization expressed in a significant decrease of a half of calculated correlation coefficients between EEGs of the visual and motor cortical areas. Nonspecific cholinergic synchronizing system is supposed to exist which is active under the conditions of the mammillo-thalamo-cortical connections being intact.     

Effect of alpha-tocopherol on the physicochemical properties of liver cell membranes in adrenalectomized rats

The increased content of lipid peroxidation products in the liver and an associated increase in the microviscosity of lipid nuclear and microsomal liver cell membranes, as well as disturbed protein-lipid interaction in them have been determined 8 days after adrenalectomy. The addition of alpha-tocopherol into the diet (4 mg per day for 7 days after the operation) prevented the activation of lipid peroxidation and the disturbances of physico-chemical membrane properties and the decrease in the muscular working capacity in rats caused by adrenalectomy.