Dominant factors of rat behavior in response to stimuli in stages

The adequacy of a modified variant of alimentary Y-maze method used by the authors was tested by studying the role of visual stage stimuli in reaction of free choice in rats. It is shown that the role of visual information is insignificant for acquiring the motor habit--finding of the shortest way to food. The dominant factors are: location of the shortest way, changing of which leads to a search behaviour by the method of "trials and errors", as well as ecologically adequate preference of edges to the center of the "distributor" and motor pretuning of the animal. Observed fixation of the choice of longer ways in comparison with the shortest one, and its stability may be explained by insufficient difference in the ways length before the reinforcement for the transformation of the habit of spatial-motor orientation into a visual one.     

Structure of the mts271 gene, coding a new calcium-binding protein

A genomic copy of the mts271 gene which is specifically expressed in metastatic cells has been cloned and characterized. The gene consists of two exons and one intron and has an open-reading frame for the protein of 101 amino acids. The protein contains two helix-loop-helix calcium-binding domains, which is a common feature for the members of the large family of intracellular calcium-binding proteins (Ca B Ps). The primary structures of the mts271 gene products and other Ca B Ps were compared. High level of homology was found for S100 and calcium-binding protein of intestinal epithelium of rats. On the whole, the mts271 protein is a new calcium-binding protein which is specifically expressed in metastatic cells.     

Enhanced transcription of genes of the intracisternal A particles and B2 elements in mouse tumors

A comparison of the expression of two mobile genetic elements A1 and B2 was studied in normal and tumor tissues. The A1 element is a chromosomal homolog of IAP genes, and B2 is a short ubiquitous repetitive sequences of the mouse genome. These sequences were earlier cloned in our laboratory and in this study were used as probes in hybridization experiments with RNA isolated from different mouse tumor and normal tissues. Both elements were efficiently transcribed in tumor cells. The level of expression of A1 sequences in tumors was 100-200 times higher than in normal tissues. The amount of B2 small cytoplasmic RNA significantly varied in different normal tissues. The content of this RNA was much higher in tumors. Closed circular DNA molecules containing IAP sequences were found in Ehrlich carcinoma cells. These DNA molecules are considered as intermediate forms of the mobile elements. The role of these mobile elements in the regulation of RNA expression and tumor progression is discussed.     

Guanine nucleotide-dependent, pertussis toxin-insensitive regulation of phosphoinositide turnover by bradykinin in bovine pulmonary artery endothelial cells

In this paper we examine the effect of the vasodilator peptide bradykinin on endothelial cell regulation of phosphoinositide (PI) turnover. The data show that the activation of PI turnover by bradykinin in bovine pulmonary artery endothelial cells is insensitive to pertussis toxin, which ADP ribosylates a membrane protein of mol wt 40,000. However, this effect of bradykinin can be potentiated by guanosine 5'-O-(3-thio)triphosphate (GTP gamma S), an activator of G proteins, and depressed by guanosine 5'-O-(2-thio)diphosphate (GDP beta S), an inhibitor of G proteins. After endothelial cells were preincubated for 1 h with GTP gamma S, there was a three- to fourfold increase in PI turnover. Preincubation of cells with GDP beta S did not affect the basal level of PI turnover, but completely prevented activation of PI turnover by bradykinin. 4 beta-Phorbol-12 beta-myristate-13 alpha-acetate can block the bradykinin-stimulated inositol monophosphate formation in cultured endothelial cells. The effects of bradykinin on PI turnover were blocked by B2 antagonists but not by B1 antagonists. Taken together, these results indicate that in endothelial cells the bradykinin B2 receptor is coupled to phospholipase C via a G protein (or proteins) that is not a substrate for pertussis toxin (neither Gi nor Go).     

Production of DON-related trichothecenes byFusarium graminearum Schw from Krasnodarski krai of the USSR

34Fusarium graminearum Schw isolates produced 4-deoxynivalenol to form significant amounts of 4, 7 — dideoxynivalenol and lesser amounts of 4 — deoxynivalenol monoacetates on grain substratesin vitro. This is the first report on the capability a large group of naturally occurring isolates to produce 4,7-dideoxynivalenol. The average levels of 4,7-dideoxynivalenol on rice, corn, barley, and wheat as a substrate were respectively 26.8, 14.0, 12.8, and 10.5% of the level of 4-deoxynivalenol. 4, 7 — dideoxynivalenol was present in all examined naturally contaminated wheat kernel samples at levels of 1.7 to 7.9% of the level of 4-deoxynivalenol. These findings suggest that more attention should be given to the occurrence of 4,7-dideoxynivalenol in cereals.     

Variation in the ribosomal internal transcribed spacers (ITS1 and ITS2) among eight taxa of the Mimulus guttatus species complex

The internal transcribed spacer region (ITS1 and ITS2) of the 18S-25S nuclear ribosomal DNA sequence and the intervening 5.8S region were sequenced from three individuals in each of eight taxa of the Mimulus guttatus species complex. Three discrete variants, or "types," of ITS sequences were found, among which 30%-40% of sites differed, compared with 1%-2% within types. Dot plots indicate that these types were not related by conspicuous rearrangements or inversions. More than one ITS type was often found in the same taxon, and two of three ITS types span species boundaries, indicating their presence prior to speciation. These ITS sequences showed essentially no positional homology with the nearest sequenced relative, tomato. In contrast, the 5.8S region was relatively unvaried, with 8 of 162 sites varied in the sample among all eight taxa. The phylogeny inferred by the most common ITS sequence type, rooted by the two other ITS types, agreed with isozymes in showing the distinctness of M. nudatus, M. laciniatus, and M. tilingii from the other five taxa.      

中国小菇属十个新记录种

报道了小菇科小菇属真菌10个中国新记录种,香菌组：橙盖小菇Mycena aurantiidisca、黄白小菇Mycena flavoalba、粉黄小菇Mycena floridula;棘刺组：异刺小菇Mycena heteracantha;纤柄组：碱味小菇Mycena amygdalina;脆足组：粉被小菇Mycena zephirus;冬生组：绣线菊小菇Mycena speirea、冬生小菇Mycena hiemalis;小菇组：绒柄小菇Mycena flos-nivium,分别来自吉林等11个省份、自治区。提供了每个物种的形态描述和线条图,以及与相近种的讨论。共计90条自测及下载ITS序列,在采用贝叶斯法和最大似然法构建的小菇属系统发育树中,新记录种均得到分子数据支持。凭证标本存放于吉林农业大学菌物标本馆（HMJAU）。