Genetic architecture of grain protein content in wheat

Studies on identification and localization of quantitative traits for grain protein content (QGpc-loci) on chromosomes in Triticum aestivum and Triticum durum are reviewed. Association of QGpc with various traits of morphology, physiology, adaptation and tolerance to abiotic and biotic stressors is shown. Genetic and environmental QGpc contexts that should be taken into account when using molecular markers in breeding for the grain protein content are considered.     

Thyroid Hormones and Activities of Lysosomal Proteolytic Enzymes in Organs of the Arctic Fox Alopex lagopus

Age-related changes of content of thyroid hormones in the blood serum and of activities of lysosomal proteinases in organs were studied in the arctic fox Alopex lagopus L. in early postnatal ontogenesis. The existence has been shown of a negative correlation between the age changes in the serum thyroxin content and lysosomal proteinase activities in some organs of these animals. The results obtained indicate predominance of anabolic function of thyroid hormones in arctic fox cubs. The problem of anabolic and catabolic effects of thyroid hormones on protein metabolism is discussed.     

Characteristics of the phase-dependent vagus effects in the heart of the frog Rana temporaria and of the cod Gadus morhua

In experiments on the heart of the cod Gadus morhua and frog Rana temporaria in situ, studies have been made of changes in the heart rate induced by stimulation of the vagal nerve by single brief bursts delivered at various intervals after P wave of the ECG. Certain differences were found in changes of the heart rate between these animals. In the cod, maximum chronotropic effect was equal to 65% of the duration of initial cardiac cycle, the latency of this effect being equal to 290 ms; in the frog, corresponding figures were 12-13% and approximately 940 ms. The duration of negative chronotropic effect in the heart of the cod was equal to 700 ms, that of the frog--to 2.700 ms. Functional role of these differences is discussed in relation to the problem of the development of parasympathetic regulation of the heart rate in phylogenesis of vertebrates.     

Effect of fucoidans on the developing embryos of the sea urchin <Emphasis Type="Italic">Strongylocentrotus intermedius</Emphasis>

Effect of fucoidans from the Far Eastern brown algae Laminaria japonica, L. cichoroides, and Fucus evanescens on developing embryos of the sea urchin Strongylocentrotus intermedius was studied. Fucoidans from these algae were shown to have different (immunostimulating, inhibitory) effects on the developing embryos. All studied fucoidan fractions added at the zygote stage had a stimulatory effect (acceleration of developmental stages and an increase of life spans) on the developing embryos, with differences by their effective concentrations. Many fucoidans added at the late blastula stage did not produce the stimulatory effect. The lowest number of immunostimulators (only a half of the tested substances) were present among fucoidans from L. japonica cichoriodes. The best immunostimulators that increased 2–3 times the life span of the embryos were heteropolysaccharides containing mannose or xylose apart from L-fucose. Some fucoidans at high concentrations produced an inhibitory effect; they were mainly composed of L-fucose or their monosaccharide composition included, apart from fucose, a significant amount of galactose, but no mannose. The method that we used turned out to be sensitive to structural peculiarities of charged polysaccharides, so it most likely can be applied for evaluation of their immunostimulating properties. From two variants of the experiment the most sensitive was the second one, in which polysaccharides were added at the late blastula stage.Translated from Zhurnal Evolyutsionnoi Biokhimii i Fiziologii, Vol. 41, No. 1, 2005, pp. 51–58.Original Russian Text Copyright © 2005 by Kiseleva, Shevchenko, Krupnova, Zvyagintseva.     

Calcium-activated neutral proteinase in gametes of the sea urchinStrongylocentrotus droebachiensis

By Chromatographic separation of cytosol fraction of homogenates from gonads of females and males of green sea urchinStrongylocentrotus droebachiensis using an AcA-34 ultragel, protein fractions with mol. mass of 123 and 81 kDa are revealed, which have activity of calcium-activated proteinases. Dynamics of activity of the calcium-activated proteinases is studied during annual sexual cycles of the sea urchin. It is shown that the maximal activity of the studied enzyme in females and males of the sea urchin is present at the IV stage of gonad maturation, at the period of their trophic growth which is characterized by formation of stores of nutritient substances necessary for the subsequent development of embryos.     

Purification and some catalytic properties of phosphoglucomutase from maize leaves

Phosphoglucomutase (EC 2.7.5.1, PGM) was purified to homogeneity from maize (Zea mays L.) leaves. The enzyme had specific activity 11. 7 U/mg protein and molecular mass (determined by gel-chromatography) of 133 +/- 4 kD. The molecular mass of PGM subunits determined by SDS-electrophoresis was 66 +/- 3 kD. The enzyme had Km for glucose-1-phosphate and glucose-1,6-diphosphate of 20.0 +/- 0.9 and 16.0 +/- 0.8 &mgr;M, respectively. Concentrations of glucose-1-phosphate and glucose-1,6-diphosphate above 3 and 0.4 mM, respectively, cause substrate inhibition. The enzyme activity was maximal at pH 8.0 and temperature 35 degreesC. Magnesium ions activate the enzyme and manganese ions inhibit it. 3-Phosphoglycerate is an uncompetitive inhibitor of the enzyme (Ki = 1.22 +/- 0.05 mM). Fructose-6-phosphate, 6-phosphogluconate, and ADP activate PGM, whereas ATP, UTP, and AMP inhibit the enzyme. Citrate was also a potent inhibitor, inhibitory effects of isocitrate and cis-aconitate being less pronounced.