杂交构树UDP-葡萄糖脱氢酶基因编码蛋白的亚细胞定位及其启动子5'端缺失片段的功能分析

为了研究杂交构树UDP-葡萄糖脱氢酶基因（DDBJ，BpUGDH基因登录号为LC457701）启动子不同区域的表达活性，利用5'端缺失及同源重组实验技术，将5个不同长度的BpUGDH启动子5'端缺失片段与GUS基因连接，并通过农杆菌介导法瞬时转化烟草；同时，为了定位BpUGDH基因编码的蛋白在细胞中表达的具体位置，利用GFP报告基因融合目的基因进行蛋白质的亚细胞定位。结果显示：BpUGDH基因启动子-244 bp以内的序列均能介导GUS基因的诱导表达，并且-973、-465、-355、-281和-244 bp之间的区域可能对BpUGDH基因启动子的活性发挥着至关重要的作用。另外，BpUGDH基因编码蛋白的亚细胞定位结果显示：BpUGDH位于叶绿体中。     

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The detection of colon cancer by using Poincaré sphere and 2D polarimetric imaging approach. Further details can be found in the article by Deyan Ivanov, Viktor Dremin, Alexander Bykov, Ekaterina Borisova, et al. ( e202000082 ).

     

Single-Channel Resolution of the Interaction between C-Terminal CaV1.3 Isoforms and Calmodulin

Voltage-dependent calcium (Ca_V) 1.3 channels are involved in the control of cellular excitability and pacemaking in neuronal, cardiac, and sensory cells. Various proteins interact with the alternatively spliced channel C-terminus regulating gating of Ca_V1.3 channels. Binding of a regulatory calcium-binding protein calmodulin (CaM) to the proximal C-terminus leads to the boosting of channel activity and promotes calcium-dependent inactivation (CDI). The C-terminal modulator domain (CTM) of Ca_V1.3 channels can interfere with the CaM binding, thereby inhibiting channel activity and CDI. Here, we compared single-channel gating behavior of two natural Ca_V1.3 splice isoforms: the long Ca_V1.3₄₂ with the full-length CTM and the short Ca_V1.3_42A with the C-terminus truncated before the CTM. We found that CaM regulation of Ca_V1.3 channels is dynamic on a minute timescale. We observed that at equilibrium, single Ca_V1.3₄₂ channels occasionally switched from low to high open probability, which perhaps reflects occasional binding of CaM despite the presence of CTM. Similarly, when the amount of the available CaM in the cell was reduced, the short Ca_V1.3_42A isoform showed patterns of the low channel activity. CDI also underwent periodic changes with corresponding kinetics in both isoforms. Our results suggest that the competition between CTM and CaM is influenced by calcium, allowing further fine-tuning of Ca_V1.3 channel activity for particular cellular needs.     

Ca++-dependent immunosuppressive effect of ethylenediaminetetraacetic acid (EDTA)]

Subcutaneous injection of a sum total dose of 6.44.10(-5) M of ethylenediaminetetraacetic acid (EDTA), which binds divalent cations, inhibits the process of accumulation of antibody-forming cells in the spleen of mice (CBA X C57BL) F1 hybrids, immunizated with sheep red blood cells. In a dose of 5.2.10(-5) M CaCl2 eliminated the immunodepressive effect of EDTA almost completely. It was assumed that EDTA action was produced through the Ca++-controlled regulation mechanism of one of the following processes: the interaction between T- and B-lymphocytes; proliferation and differentiation of T- and B-cells in the course of the immune response to sheep red blood cells. A more complex mechanism of EDTA action on the above-mentioned processes is not excluded, however.     

Activity of various enzymes of energy metabolism of the myocardium after neurogenic injury]

A 3-hour electrostimulation of the aortic arch in rabbits was followed by the exhastion of the tissue noradrenaline stores in the myocardium accompanied by increase in the activity of the glycolysis enzymes and of the enzyme limiting the process of the pentosophosphate route-G-6-PDH. The use of noradrenaline precursor - 1-DOPA restored the noradrenaline level in the myocardium completely after a 48-hour stimulation. Simultaneously there were noted no changes in the activity of the enzymes under study caused by the stimulation of the aortic arch. The data obtained confirmed the important role of the sympathetic nervous system and of its mediator - noradrenaline in the mechanism of the tissue metabolism regulation, whose derangement played a significant role in the development of dystrophic lesions of the heart tissue.     

The electrophoretic typing of rotaviruses in the clinico-epidemiological study of infection]

The electrophoretic study of the RNA of human rotavirus strains (1146 strains) circulating in 9 cities at the territory of the European part of the RSFSR was carried out. The electrophoretic (EP) types of rotavirus were established in each individual area. The study revealed that the most widespread rotaviruses responsible for the majority of gastroenteritis cases are those with the long EP type of RNA, characterized by the joint migration of segments 2, 3 and 7 (the 3rd EP type of RNA). Rotaviruses with the 3rd EP type of RNA much more often induce a severe course of rotavirus gastroenteritis in children aged 8 months to 3 years.     

Phenomenon of parental resistance and its genetic regulation]

Lymphocytes of mice F1 (CBA X M523) and F1 (A X M523) transplanted to 1000 R irradiated CBA or A mice responded to the test antigens--SRBC or S. typhi Vi-antigen--by formation of 100--1000 times less antibody forming cells than in syngeneic recipients. An intermediate result is achieved when the lymphoid cells are transplanted to the irradiated M523 mice. Lymphocytes of mice F1 (A X CBA), F1 (CBA X C57Bl/6), or F1 (A X A.CA) developed a similar immune response in the irradiated syngeneic mice and in both parental lines. The ability of parental line M523 to respond to SRBC was the same as in the other lines studied when examined in situ or in adoptive transfer experiments. The stem hemopoietic cells of mice F1 (CBA X M523) develop in the spleen of CBA mice 2--2.5 times less hemopoietic colonies than in the spleen of syngeneic animals. A conclusion was drawn that mutation M523 in CBA mice inhibited the proliferation and differentiation of hemopoietic and lymphoid cells in the irradiated nonsyngeneic recipients.     

Double satellites do not increase the risk of chromosome 21 nondisjunction

The hypothesis concerning the increase of the risk of appearance of offsprings with trisomy 21 in parents having double satellite acrocentric chromosomes is checked. Chromosomes of 266 parents having offsprings with Down's disease were examined, including 73 donors of extrachromosome 21. The frequency of chromosomes with dNORs in the total and in the donor groups did not differ from that of the control group. From 42 donors of extrachromosome, who demonstrated a nondisjunction in the first meiotic division, double satellites were revealed only once. In addition, data on the frequency of Dp+ and Gp+ variants are presented and discussed.