Effects of Water Deficit during Germination of Wheat Seeds

Germinating seeds of spring wheat (Triticum aestivum L.) were tolerant to dehydration up to the 4^th day following imbibition and from the 5^th day the seedling survival decreased. Dehydration also inhibited the rate of seed dry mass depletion and seedling dry matter accumulation and increased the content of soluble sugars both in grain and seedlings. Glucose supplied either to dry seeds or to 4-d-old seedlings increased survival of dehydrated seedlings. In contrast, exogenously supplied non-readily metabolizable sorbose and mannose suppressed seedling survival.     

Polygenic risk scores for alcohol involvement relate to brain structure in substance-naïve children: Results from the ABCD study

Brain imaging-derived structural correlates of alcohol involvement have largely been speculated to arise as a consequence of alcohol exposure. However, they may also reflect predispositional risk. In substance naïve children of European ancestry who completed the baseline session of the Adolescent Brain Cognitive Development (ABCD) Study (n = 3013), mixed-effects models estimated whether polygenic risk scores (PRS) for problematic alcohol use (PAU-PRS) and drinks per week (DPW-PRS) are associated with magnetic resonance imaging-derived brain structure phenotypes (i.e., total and regional: cortical thickness, surface area and volume; subcortical volume; white matter volume, fractional anisotropy, mean diffusivity). Follow-up analyses evaluated whether any identified regions were also associated with polygenic risk among substance naïve children of African ancestry (n = 898). After adjustment for multiple testing correction, polygenic risk for PAU was associated with lower volume of the left frontal pole and greater cortical thickness of the right supramarginal gyrus (|βs| > 0.009; ps < 0.001; ps_fdr < 0.046; r²s < 0.004). PAU PRS and DPW PRS showed nominally significant associations with a host of other regional brain structure phenotypes (e.g., insula surface area and volume). None of these regions showed any, even nominal association among children of African ancestry. Genomic liability to alcohol involvement may manifest as variability in brain structure during middle childhood prior to alcohol use initiation. Broadly, alcohol-related variability in brain morphometry may partially reflect predisposing genomic influence. Larger discovery genome-wide association studies and target samples of diverse ancestries are needed to determine whether observed associations may generalize across ancestral origins.     

Cestode lysosomes

By differential centrifugation method a lysosomal fraction was obtained from five species of cestodes, which possesses the highest specific activity of acidic phosphatases as compared to other subcellular fractions. By isopyknic centrifugation in the density gradient of saccharose the lysosomal fraction is divided into primary and secondary lysosomes. Lysosomes of cestodes are similar to those of vertebrate animals in the character of fractional distribution of acidic phosphatase, sedimentation abilities and sensitivity of membranes to triton X-100.     

Avian botulism during late autumn and early spring in Saskatchewan

Two outbreaks of botulism in central Saskatchewan in which mortality of waterfowl continued into late autumn and then recurred in the same marshes the following spring are described. Small numbers of birds were involved in each instance. Dabbling ducks (predominantly mallards, Anas platyrhynchos and pintails, Anas acuta) and American coots, Fulica americana were affected most commonly in autumn, whereas only diving ducks (predominantly lesser scaup, Aythya affinis) were found to be involved in spring. Live maggots present in carcasses despite sub-freezing temperatures were the probable source of intoxication in the autumn; the source of toxin in the spring was not determined.     

Theoretical investigations on the conformation of 1,5,N(4)-tetramethylcytosine

Theoretical investigations (Perturbative Configuration Interaction over Localized Orbitals (PCILO) and Intermediate Neglect of Differential Overlap (INDO) methods) of the conformation of tetramethylcystosine, an overcrowded molecule with planar struture, have carried out. The Physical features of rotational bending potentials of the dimethylamimo group are discussed. Particulary, the controversial problem concerning the planarity of the molecule is investigated. The obtained results show that the planarity of tetrathylcytosine is an intrinsic property of the molecule. Nevertheless, because of the repulsion between the methyl groups, the planar structure of tetramethylcytosine is slightly destabilized. Further, the functional dependence of the dipole moment of tetramethylcytosine on rotation and bending of the dimethylamino group has been analyzed.     

Porphyrin-like compounds genesis under simulated abiotic conditions

Experiments with gas mixtures intended to simulate the primaeval atmosphere of the Earth yielded many biologically important chemicals. Investigations into the synthesis of porphyrinlike compounds from methane, ammonia and water vapour were carried out by using high frequency discharges. Microanalyses of porphyrins showed that porphyrin-like pigments were formed in this way. The presence of divalent cations in the reaction system increased the yield of porphyrin-like pigments also involving the direct synthesis of their metal complexes.The ready formation of these compounds in abiotic conditions is significant, suggesting the possibility of their appearance during the early stage of chemical evolution.     

Mode of interaction of the Gαo subunit of heterotrimeric G proteins with the GoLoco1 motif of Drosophila Pins is determined by guanine nucleotides

Drosophila GoLoco motif-containing protein Pins is unusual in its highly efficient interaction with both GDP- and the GTP-loaded forms of the α-subunit of the heterotrimeric Go protein. We analysed the interactions of Gαo in its two nucleotide forms with GoLoco1–the first of the three GoLoco domains of Pins–and the possible structures of the resulting complexes, through combination of conventional fluorescence and FRET measurements as well as through molecular modelling. Our data suggest that the orientation of the GoLoco1 motif on Gαo significantly differs between the two nucleotide states of the latter. In other words, a rotation of the GoLoco1 peptide in respect with Gαo must accompany the nucleotide exchange in Gαo. The sterical hindrance requiring such a rotation probably contributes to the guanine nucleotide exchange inhibitor activity of GoLoco1 and Pins as a whole. Our data have important implications for the mechanisms of Pins regulation in the process of asymmetric cell divisions.