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991.
992.
993.
Yvonne M Searls Rajprasad Loganathan Irina V Smirnova Lisa Stehno-Bittel 《Cardiovascular diabetology》2010,9(1):1-17
Background
Diminished calcium (Ca2+) transients in response to physiological agonists have been reported in vascular smooth muscle cells (VSMCs) from diabetic animals. However, the mechanism responsible was unclear.Methodology/Principal Findings
VSMCs from autoimmune type 1 Diabetes Resistant Bio-Breeding (DR-BB) rats and streptozotocin-induced rats were examined for levels and distribution of inositol trisphosphate receptors (IP3R) and the SR Ca2+ pumps (SERCA 2 and 3). Generally, a decrease in IP3R levels and dramatic increase in ryanodine receptor (RyR) levels were noted in the aortic samples from diabetic animals. Redistribution of the specific IP3R subtypes was dependent on the rat model. SERCA 2 was redistributed to a peri-nuclear pattern that was more prominent in the DR-BB diabetic rat aorta than the STZ diabetic rat. The free intracellular Ca2+ in freshly dispersed VSMCs from control and diabetic animals was monitored using ratiometric Ca2+ sensitive fluorophores viewed by confocal microscopy. In control VSMCs, basal fluorescence levels were significantly higher in the nucleus relative to the cytoplasm, while in diabetic VSMCs they were essentially the same. Vasopressin induced a predictable increase in free intracellular Ca2+ in the VSMCs from control rats with a prolonged and significantly blunted response in the diabetic VSMCs. A slow rise in free intracellular Ca2+ in response to thapsigargin, a specific blocker of SERCA was seen in the control VSMCs but was significantly delayed and prolonged in cells from diabetic rats. To determine whether the changes were due to the direct effects of hyperglycemica, experiments were repeated using cultured rat aortic smooth muscle cells (A7r5) grown in hyperglycemic and control conditions. In general, they demonstrated the same changes in protein levels and distribution as well as the blunted Ca2+ responses to vasopressin and thapsigargin as noted in the cells from diabetic animals.Conclusions/Significance
This work demonstrates that the previously-reported reduced Ca2+ signaling in VSMCs from diabetic animals is related to decreases and/or redistribution in the IP3R Ca2+ channels and SERCA proteins. These changes can be duplicated in culture with high glucose levels. 相似文献994.
Galina V. Smirnova Galina I. Vysochina Nadezda G. Muzyka Zoya Y. Samoylova Tatyana A. Kukushkina Oleg N. Oktyabrsky 《World journal of microbiology & biotechnology》2010,26(12):2269-2276
The antioxidant activities of extracts from leaves of the medicinal plants growing in Siberia were examined. Total antioxidant
activity was determined using in vitro methods including DPPH (2,2-diphenyl-1-picrylhydrazyl radical) free radical scavenging
assay, chelating capacity assay with ferrozine, evaluation of capacity to protect plasmid DNA against oxidative damage, measurement
of H2O2 production, and measurement of total flavonoid and tannin content as well. Using in vivo experiments, we also evaluated capacities
of the plant extracts to protect bacteria Escherichia
coli against bacteriostatic and bactericidal effects of H2O2, and influence of the plant extracts on expression of antioxidant gene katG, encoding catalase. The extracts from Chamerion
angustifolium, Filipendula
vulgaris and Pyrola
rotundifolia indicated the highest levels of antioxidant activity both in vivo and in vitro. Our data suggest that the extracts of the
tested plants may provide antioxidant effects on bacteria simultaneously through different pathways, including direct radical
scavenging, iron chelation and induction of genes encoding antioxidant enzymes. 相似文献
995.
Galina V. Smirnova Zoya Y. Samoylova Nadezda G. Muzyka Oleg N. Oktyabrsky 《Free radical biology & medicine》2009,46(6):759-768
Among all polyphenols tested (tannic acid and flavonoids belonging to different subclasses) only tannin and quercetin significantly enhanced resistance of Escherichia coli to peroxide stress. Pretreatment of the cells with quercetin and tannin resulted in a decrease in the growth arrest duration under moderate H2O2 concentration (2 mM) and an increase in survival under high (10 mM) doses. The shorter growth recovery period in pretreated cells was connected with more rapid H2O2 elimination because of induced activity of scavenging enzymes. This effect was absent in the ΔoxyR mutant, which was unable to induce genes responding to peroxide stress. The data obtained suggest that the observed protection was a result of two overlapping effects: induction of OxyR regulon by low concentrations of H2O2, accumulated during extracellular autoxidation of quercetin and tannin, and protection of synthesis of OxyR-regulated antioxidant enzymes during H2O2 stress because of intracellular binding of iron by quercetin and tannin and suppressing Fenton chemistry. 相似文献
996.
N. R. Meychik A. V. Smirnova N. P. Matveeva Yu. I. Nikolaeva I. P. Ermakov 《Russian Journal of Plant Physiology》2009,56(2):211-218
Changes in the composition of ionogenic groups of the polymeric matrix of the cell walls of lily (Lilium longiflorum Thunb.) pollen grains were studied during its activation at the early stages of pollen germination. In the cell walls isolated from nonactivated and activated pollen grains, four types of ionogenic groups were identified: amino groups, carboxylic groups of uronic acids, phenolic OH-groups. and groups with pKa 7–8. During the early stages of germination, ionization constants of each type groups remained unchanged, but the quantitative composition of ionogenic groups in the intine changed. In this matrix, a decrease in the content of phenolic groups and demethylated carboxylic groups of uronic acids was detected. It is supposed that, at early stages of germination, the intine loses some part of acid pectins and some phenolic compounds. 相似文献
997.
Nina A. Shanina Ekaterina Y. Skorova Elena A. Smirnova 《Cell biology international》2009,33(3):290-300
Antibodies were produced against fragments of the microtubule-binding domain and the motor domain of the dynein heavy chain from Dictyostelium discoideum to probe whole cell extracts of root meristem cells of wheat Triticum aestivum. In plant extracts, these antibodies cross-reacted with a polypeptide of high molecular weight (>500 kDa). The antibodies bound to protein A-Sepharose precipitated high molecular weight polypeptide from cell extracts. Immunofluorescence showed that the antibodies identified various aggregates inside cells, localized at the perinuclear area during interphase to early prophase, at the spindle periphery and polar area during mitosis, and in the interzonal region during phragmoplast development. Some aggregates were also co-labeled by markers for the Golgi apparatus. Thus, we found in higher plant cells a high molecular weight antigen cross-reacting with the antibodies to motor and microtubule-binding domains of dynein heavy chains. This antigen is associated with aggregates distributed in the cytoplasm in cell cycle-dependent manner. A subset of these aggregates belongs to the Golgi complex. 相似文献
998.
Irina S. Smirnova 《Cellular immunology》2010,261(1):29-2205
The extracellular signal-regulated kinases 1/2 (ERK1/2) are serine/threonine-selective protein kinases involved in proliferation and differentiation of cells, including thymocytes. The requirement of ERK1/2 for thymocyte differentiation and maturation has been well established; however, their role in regulating thymocyte survival and apoptosis has not been resolved.Here, we asked whether ERK1/2 affected thymocyte survival in vitro in response to apoptotic stimuli. The results show that phorbol 12-myristate 13-acetate (PMA) treatment (with or without ionomycin) and serum starvation (s/s) induced sustained ERK1/2 activation in murine thymocytes. Importantly, pharmacological treatment of thymocytes with the MEK inhibitor UO126 revealed that PMA-induced ERK1/2 activation was proapoptotic, whereas serum starvation-induced ERK1/2 activation inhibited apoptosis and promoted cell survival. While basal MEK activity was required for both s/s- and PMA-induced ERK1/2 activation, MEK activity increased only in response to PMA. The results show that the suppression of ERK1/2 phosphatases was responsible for s/s-induced sustained ERK1/2 activation. Unexpectedly, neither s/s-induced proapoptotic nor PMA-induced anti-apoptotic functions of ERK1/2 depended on the Bcl-2 family phosphoprotein BimEL, which was previously implicated in thymocyte apoptosis. Lastly, etoposide treatment of immature thymocytes induced both p53 and ERK1/2 activation, but ERK1/2 activity did not affect the phosphorylation and stabilization of p53. Thus, ERK1/2 has a dual role in promoting cell survival and cell death in thymocytes in the context of different stimuli. 相似文献
999.
Podboronov VM Kuzovnikov AE Zaĭtseva AK Smirnova IP 《Antibiotiki i khimioterapii͡a》2010,55(9-10):33-36
The effect of L-lysine-alpha-oxidase from a representative of the Trichoderma genus on the humoral immune response to protein antigens was studied. It was shown that repeated fife-fold intravenous administrations of L-lysine-alpha-oxidase in a dose of 35 U/kg had no depressive action on the humoral immunity. The enzyme had no suppressive effect on the delayed type hypersensitivity to xenogenous erythrocytes. The use of L-lysine-alpha-oxidase in a therapeutic dose or in a twice as higher dose had no reliable effect on the leukocyte migration capacity vs. the control. 相似文献
1000.
We studied concentrations of cortisol, its precursors and active form in human blood and relation to the changes in concentration of central and peripheral hormonal regulators (total 36 parameters) in healthy male volunteers aged 18-72 y.o. The study demonstrated a significant decrease in blood concentrations of unutilazed cortisol precursors (pregnenolone and progesterone) with advanced age accompanied by maintenance of total and free cortisol concentrations. We found age-related decrease in ACTH level that is a known hypophysial stimulant of cortisol and cortisol precursor synthesis in adrenal glands. Cortisol and ACTH levels in study population had different correlation behavior in relation to central and peripheral regulators for hormonal axes. CONCLUSION: cortisol level remains stable with advanced age in males despite the decrease in steroidogenic activity and blood ACTH level. This may be due to the imbalance in the regulation of cortisol and ACTH production by central and peripheral regulators especially by hormones of reproductive and somatotrophic axes. 相似文献