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81.
E. V. Navolotskaya T. A. Zargarova T. N. Lepikhova V. L. Turobov R. I. Nurieva N. V. Malkova V. P. Zav’yalov V. M. Lipkin 《Russian Journal of Bioorganic Chemistry》2000,26(1):27-33
The antiproliferative and immunosuppressivein vitro effects ofimmunocortin, a synthetic adrenocorticotropin-like (ACTH-like) decapeptide H-Val-Lys-Lys-Pro-Gly-Ser-Ser-Val-Lys-Val-OH, whose sequence
corresponds to segment 11–20 of the variable part of the human IgG1 heavy chain, were studied. At concentrations of 10−11−10−7 M, immunocortin was found to inhibit the growth of the human MT-4 T-lymphoblastoid cell line, to suppress the blast transformation
of thymocytes, and to decrease the spontaneous mobility of peritoneal macrophages and their bactericidal action toward the
virulent strainSalmonella typhimurium 415. By using a125I-labeled “addressing” fragment of ACTH {[125I]ACTH (13–24)}, we showed that MT-4 cells express specific receptors for ACTH (K
d 97 pM). Immunocortin and human ACTH (but not the heavy chain of IgG1) competitively inhibited the binding of [125I]ACTH-(13–24) to these receptors withK
i1 of 0.38 andK
i2 of 0.34 nM, respectively. Specific receptors for ACTH (K
d 5.8 nM) on mouse thymocytes were detected and characterized. The unlabeled immunocortin was shown to compete with labeled
ACTH-(13–24) for binding to these receptors (K
i=1.8 nM), and this binding of immunocortin to receptors on thymocytes activates adenylate cyclase from these cells and increases
the intracellular concentration of cAMP. 相似文献
82.
Mayilvahanan Shanmugam Dan Li Shumin Gao Nadezhda Fefelova Vikas Shah Antanina Voit Ronald Pachon Ghassan Yehia Lai-Hua Xie Gopal J. Babu 《PloS one》2015,10(2)
The functional importance of threonine 5 (T5) in modulating the activity of sarcolipin (SLN), a key regulator of sarco/endoplasmic reticulum (SR) Ca2+ ATPase (SERCA) pump was studied using a transgenic mouse model with cardiac specific expression of threonine 5 to alanine mutant SLN (SLNT5A). In these transgenic mice, the SLNT5A protein replaces the endogenous SLN in atria, while maintaining the total SLN content. The cardiac specific expression of SLNT5A results in severe cardiac structural remodeling accompanied by bi-atrial enlargement. Biochemical analyses reveal a selective downregulation of SR Ca2+ handling proteins and a reduced SR Ca2+ uptake both in atria and in the ventricles. Optical mapping analysis shows slower action potential propagation in the transgenic mice atria. Doppler echocardiography and hemodynamic measurements demonstrate a reduced atrial contractility and an impaired diastolic function. Together, these findings suggest that threonine 5 plays an important role in modulating SLN function in the heart. Furthermore, our studies suggest that alteration in SLN function can cause abnormal Ca2+ handling and subsequent cardiac remodeling and dysfunction. 相似文献
83.
Teodora Lupanova Nadezhda Stefanova Diana Petkova Galya Staneva Albena Jordanova Kamen Koumanov Roumen Pankov Albena Momchilova 《Molecular and cellular biochemistry》2010,345(1-2):215-222
Naringenin (NGEN), a naturally occurring citrus flavonone, has shown cytotoxicity in various human cancer cell lines as well as inhibitory effects on tumor growth. It has been also shown to access the brain and there is an increasing interest in its therapeutic applications. The up-regulated expression of Cx43 leads to the suppression of tumorigenicity with promoted apoptotic events. In this study, we investigated the in vivo effect of NGEN in fostering apoptosis in cerebrally implanted C6 glioma cells rat model. We analysed the expression of Cx43, caspase-3, caspase-9, Cyt C, Bcl-2 and Bax in vivo by immunoblot analysis and the ultra structure of brain cells by transmission electron microscopy. Supplementation of NGEN to experimental animals modulated Bcl-2/Bax ratio and up-regulation of caspase-3 and 9. NGEN was also found to up-regulate the expression of Cx43. These findings provide evidence that NGEN’s apoptotic effect, modulation of Bcl-2/Bax ratio leads to release of Cyt C from mitochondria, thereby activation of caspase-3 and caspase-9 is mediated by enhanced expression of Cx43. These observations were well supported by the transmission electron microscopic results which showed the characteristic apoptotic features. In conclusion, our findings demonstrate that NGEN promotes apoptosis in rat C6 glioma model. 相似文献
84.
Tatiana D. Zinchenko Michail I. Gladyshev Olesia N. Makhutova Nadezhda N. Sushchik Galina S. Kalachova Larisa V. Golovatyuk 《Hydrobiologia》2014,722(1):115-128
Saline rivers are supposed to be ‘hot spots’ of high biological productivity in arid landscapes. To test this, we quantified the production of chironomid larvae, because river production is known to be transferred to arid landscapes primarily by birds fed on these larvae. In addition, we studied the potential biochemical quality of the larvae for birds based on the essential highly unsaturated fatty acid (HUFA) contents in their biomass. We studied species composition and measured production of chironomid larvae in two saline rivers (Volgograd region, Russia). We also evaluated the fatty acid composition and contents of the dominant taxa and estimated the flux of HUFA from the studied saline rivers to land via chironomid potential emergence. Average monthly production of chironomids measured for only 1 month, August, was quite comparable to annual production in some freshwater rivers. All the dominant chironomid larvae had comparatively high essential eicosapentaenoic acid contents, especially Cricotopus salinophilus, which showed the highest value, reported for Chironomidae. The monthly flux of HUFA from the studied rivers to land due to the chironomid potential emergence was roughly comparable to the global average estimation of annual water–land HUFA export via emerging insects. 相似文献
85.
Christian Schöneich Elena Dremina Nadezhda Galeva Victor Sharov 《Apoptosis : an international journal on programmed cell death》2014,19(1):42-57
Muscle cell apoptosis accompanies normal muscle development and regeneration, as well as degenerative diseases and aging. C2C12 murine myoblast cells represent a common model to study muscle differentiation. Though it was already shown that myogenic differentiation of C2C12 cells is accompanied by enhanced apoptosis in a fraction of cells, either the cell population sensitive to apoptosis or regulatory mechanisms for the apoptotic response are unclear so far. In the current study we characterize apoptotic phenotypes of different types of C2C12 cells at all stages of differentiation, and report here that myotubes of differentiated C2C12 cells with low levels of anti-apoptotic Bcl-2 expression are particularly vulnerable to apoptosis even though they are displaying low levels of pro-apoptotic proteins Bax, Bak and Bad. In contrast, reserve cells exhibit higher levels of Bcl-2 and high resistance to apoptosis. The transfection of proliferating myoblasts with Bcl-2 prior to differentiation did not protect against spontaneous apoptosis accompanying differentiation of C2C12 cells but led to Bcl-2 overexpression in myotubes and to significant protection from apoptotic cell loss caused by exposure to hydrogen peroxide. Overall, our data advocate for a Bcl-2-dependent mechanism of apoptosis in differentiated muscle cells. However, downstream processes for spontaneous and hydrogen peroxide induced apoptosis are not completely similar. Apoptosis in differentiating myoblasts and myotubes is regulated not through interaction of Bcl-2 with pro-apoptotic Bcl-2 family proteins such as Bax, Bak, and Bad. 相似文献
86.
Michail I. Gladyshev Nadezhda N. Sushchik Olga P. Dubovskaya Olesia N. Makhutova Galina S. Kalachova 《Aquatic Ecology》2008,42(4):617-627
Specific growth rates (based on biomass increment in unit time) of Daphnia fed natural reservoir seston from a eutrophic Siberian reservoir were studied during four vegetation seasons in a laboratory
flow-through system. Concentrations of particulate C, N, and P in reservoir seston <115 μm were comparatively high, 1.9, 0.2,
and 0.05 mg l−1, respectively; maximum C:P ratio was 259 mol:mol. According to conventional thresholds, concentrations of elements and their
stoichiometry did not limit the growth rate of Daphnia. Eicosapentaenoic acid (EPA) in seston significantly effected the growth rates at concentrations up to ∼13 μg l−1 (regression ANOVAR F-test value was 7.91), but not above this concentration. Thus, we consider this concentration of EPA in seston <115 μm to
be the limiting concentration of EPA for the growth of Daphnia (longispina group), i.e., below this concentration EPA was the best single predictor of the growth of Daphnia. 相似文献
87.
88.
Inna Golubovskaya Nadezhda A. Avalkina William F. Sheridan 《Genesis (New York, N.Y. : 2000)》1992,13(6):411-424
A modified enzyme digestion technique of ovary isolation followed by staining and squash preparation has allowed us to observe female meiosis in normal maize meiotically dividing megaspore mother cells (MMCs). The first meiotic division in megasporogenesis of maize is not distinguishable from that in mi-crosporogenesis. The second female meiotic division is characterized as follows: (1) the two products of the first meiotic division do not simultaneously enter into the second meiotic division; as a rule, the chalazal-most cell enters division earlier than the micropylar one, (2) often the second of the two products does not proceed with meiosis, but degenerates, and (3) only a single haploid meiotic product of the tetrad remains alive, and this cell proceeds with three rounds of mitoses without any intervening cell wall formation to produce the eight-nucleate embryo sac. This technique has allowed us to study the effects of five meiotic mutations (aml, aml-pral, afdl, dsy *-9101, and dvl) on female meiosis in maize. The effects of the two alleles of the aml gene (aml and aml-pral) and of the afdl and dsy *-9101mutations are the same in both male and female meiosis. The aml allele prevents the entrance of MMCs into meiosis and meiosis is replaced by mitosis; the aml-pral permits MMCs to enter into meiosis, but their progress is stopped at early prophase I stages. The afdl gene is responsible for substitution of the first meiotic (reductional) division by an equational division including the segregation of sister chromatid centromeres at anaphase I. The dsy * -9101 gene exhibits abnormal chromosome pairing; paired homologous chromosomes are visible at pachytene, but only univalents are observed at diakinesis and metaphase I stages. These mutation specific patterns of abnormal meiosis are responsible for the bisexual sterility of these meiotic mutants. The abnormal divergent shape of the spindle apparatus and the resulting abnormal segregation of homologous chromosomes observed in micro-sporogenesis in plants homozygous for the dv1 mutation have not been found in meiosis of megasporogenesis. Only male sterility is induced by the dv1 gene in the homozygous condition. © 1993 Wiley-Liss, Inc. 相似文献
89.
Dimitry Y. Sorokin Tatiana V. Khijniak Nadezhda A. Kostrikina Alexander G. Elcheninov Stepan V. Toshchakov Nicole J. Bale Jaap S. Sinninghe Damsté Ilya V. Kublanov 《Systematic and applied microbiology》2018,41(4):355-362
Six strains of extremely halophilic and alkaliphilic euryarchaea were enriched and isolated in pure culture from surface brines and sediments of hypersaline alkaline lakes in various geographical locations with various forms of insoluble cellulose as growth substrate. The cells are mostly flat motile rods with a thin monolayer cell wall while growing on cellobiose. In contrast, the cells growing with cellulose are mostly nonmotile cocci covered with a thick external EPS layer. The isolates, designated AArcel, are obligate aerobic heterotrophs with a narrow substrate spectrum. All strains can use insoluble celluloses, cellobiose, a few soluble glucans and xylan as their carbon and energy source. They are extreme halophiles, growing within the range from 2.5 to 4.8 M total Na+ (optimum at 4 M) and obligate alkaliphiles, with the pH range for growth from 7.5 to 9.9 (optimum at 8.5–9). The core archaeal lipids of strain AArcel5T were dominated by C20–C20 dialkyl glycerol ether (DGE) (i.e. archaeol) and C20–C25 DGE in nearly equal proportion. The 16S rRNA gene analysis indicated that all six isolates belong to a single genomic species mostly related to the genera Saliphagus-Natribaculum-Halovarius. Taking together a substantial phenotypic difference of the new isolates from the closest relatives and the phylogenetic distance, it is concluded that the AArcel group represents a novel genus-level branch within the family Natrialbaceae for which the name Natronobiforma cellulositropha gen. nov., sp. nov. is proposed with AArcel5T as the type strain (JCM 31939T = UNIQEM U972T). 相似文献
90.
Olga Zakharova Olga Luzina Alexandra Zakharenko Dmitry Sokolov Alexandr Filimonov Nadezhda Dyrkheeva Arina Chepanova Ekaterina Ilina Anna Ilyina Kristina Klabenkova Boris Chelobanov Dmitry Stetsenko Ayesha Zafar Chatchakorn Eurtivong Jóhannes Reynisson Konstantin Volcho Nariman Salakhutdinov Olga Lavrik 《Bioorganic & medicinal chemistry》2018,26(15):4470-4480
Tyrosyl-DNA phosphodiesterase 1 (Tdp1) is a repair enzyme for stalled DNA-topoisomerase 1 (Top 1) cleavage complexes and other 3′-end DNA lesions. Tdp1 is a promising target for anticancer therapy, since it can repair DNA lesions caused by Top1 inhibitors leading to drug resistance. Hence, Tdp1 inhibition should result in synergistic effect with Top1 inhibitors. Twenty nine derivatives of (+)-usnic acid were tested for in vitro Tdp1 inhibitory activity using a fluorescent-based assay. Excellent activity was obtained, with derivative 6m demonstrating the lowest IC50 value of 25?nM. The established efficacy was verified using a gel-based assay, which gave close results to that of the fluorescent assay. In addition, molecular modeling in the Tdp1 substrate binding pocket suggested plausible binding modes for the active analogues. The synergistic effect of the Tdp1 inhibitors with topotecan, a Top1 poison in clinical use, was tested in two human cell lines, A-549 and HEK-293. Compounds 6k and 6x gave very promising results. In particular, 6x has a low cytotoxicity and an IC50 value of 63?nM, making it a valuable lead compound for the development of potent Tdp1 inhibitors for clinical use. 相似文献