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1.
G E Grigorian A M Stol'berg 《Zhurnal vysshe? nervno? deiatelnosti imeni I P Pavlova》1987,37(3):478-484
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. 相似文献
2.
E M Tul'chinski? A K Ebralidze M S Grigorian N V Mil'shchina E M Lukanidin 《Genetika》1989,25(7):1150-1159
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. 相似文献
3.
M S Grigorian D A Kramerov E M Tul'chinski? E S Revazova E M Lukanidin 《Molekuliarnaia biologiia》1985,19(2):340-348
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. 相似文献
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5.
T A Voyno-Yasenetskaya V A Tkachuk E G Cheknyova M P Panchenko G Y Grigorian R J Vavrek J M Stewart U S Ryan 《FASEB journal》1989,3(1):44-51
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). 相似文献
6.
The ATP-binding-cassette transmembrane transporters (ABC transporters)
known from vertebrates belong to four major subfamilies: (1) the P-
glycoproteins (Pgp); (2) the cystic fibrosis transmembrane conductance
regulators (CFTR); (3) the Tap proteins encoded with the major
histocompatibility complex of mammals; and (4) the peroxisomal membrane
proteins. Both Pgp and CFTR have a structure suggesting a past internal
gene duplication; a phylogenetic analysis indicated that these duplications
occurred independently, while an independent tandem gene duplication
occurred in the case of the Tap family. Both the Pgp and Tap proteins show
evidence of relationship to bacterial ABC transporters lacking internal
duplication, and both are significantly more closely related to the HlyB
and MsbA families of transporters from purple bacteria than they are to ABC
transporters from nonpurple bacteria. The simplest hypothesis to explain
this observation is that eukaryotic Pgp and Tap genes are descended from a
mitochondrial gene or genes that were subsequently translocated to the
nuclear genome. The Pgp genes of eukaryotes are characterized by a
remarkable degree of convergent evolution between the ATP-binding cassettes
of their N- terminal and C-terminal halves, whereas no such convergence is
seen between the two halves of CFTR genes or between the duplicated Tap
genes. Exon 13 of the CFTR gene, which encodes a putative regulatory domain
not found in other ABC transporters apart from CFTR, showed high levels of
both synonymous and nonsynonymous difference in comparisons among different
mammalian species, suggesting that this region is a mutational hot spot.
相似文献
7.
8.
X Xiao G Hintermann AL Demanin J Piret 《Journal of industrial microbiology & biotechnology》1996,16(4):261-262
Streptomyces glaucescens is shown to possess -lactamase activity which is inhibitable by clavulanate. This is important in regard to its use as a cloning host for enzymes of \-lactam biosynthesis. 相似文献
9.
10.
ERIC S. BONO PATRICK SMOLINSKI AL CASAGRANDA JUNDE XU 《Computer methods in biomechanics and biomedical engineering》2013,16(2):125-131
The Shear-slip Mesh Update Method (SSMUM) is being used in flow simulations involving large but regular displacements of one or more boundaries of the computational domain. We follow up the earlier discussion of the method with notes on practical implementation aspects. In order to establish a benchmark problem for this class of flow problems, we define and report results from a two-dimensional viscous flow around a rotating stirrer in a square chamber. The application potential of the method is demonstrated in the context of biomedical design problem, as we perform an analysis of blood flow in a centrifugal left ventricular assist device, or blood pump, which involves a rotating impeller in a non-axisymmetric housing. 相似文献