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81.
Vasiukova NI Zinov'eva SV Il'inskaia LI Perekhod EA Chalenko GI Gerasimova NG Il'ina AV Varlamov VP Ozeretskovskaia OL 《Prikladnaia biokhimiia i mikrobiologiia》2001,37(1):115-122
Low-molecular-weight water-soluble chitosan with a molecular weight of 5 kDa obtained after enzymatic hydrolysis of native crab chitosan was shown to display an elicitor activity by inducing the local and systemic resistance of Solanumi tuberosum potato and Lycopesicon esculentum tomato to Phytophthora infestans and nematodes, respectively. Chitosan induced the accumulation of phytoalexins in tissues of host plants, decreased the total content and changed the composition of free sterols producing adverse effects on infesters, activated chitinases, beta-glucanases, and lipoxygenases, and stimulated the generation of reactive oxygen species. The activation of protective mechanisms in plant tissues inhibited the growth of taxonomically different pathogens (parasitic fungus Phytophthora infestans and root knot nematode Meloidogyne incognita). 相似文献
82.
Osadchiĭ LI Balueva TV Sergeev IV Vershinina EA 《Rossi?skii fiziologicheski? zhurnal imeni I.M. Sechenova / Rossi?skaia akademiia nauk》2001,87(1):90-96
In anesthetized rats, a reverse linear correlation of arterial pressure (AP) shifts was found within the range of initial AP over 95 mm Hg under the head-up tilts at 30 and 45 degrees. Within the range beneath 95 mm Hg this correlation was transformed into the direct one. Under 60 degrees tilt such correlation only occurred within the range beneath 95 mm Hg. The direction and degree of the arterial system responsiveness seems to depend on the tilt value as well as on the range of the initial AP. 相似文献
83.
Priakhin EA Korytnyĭ VS Akleev AV Krupitskaia LI Anisimova GG Tolstykh EI Triapitsyna GA 《Radiatsionnaia biologiia, radioecologiia / Rossi?skaia akademiia nauk》2001,41(2):141-152
The response of bone marrow cells of CBA mice injected with 22.2, 222 and 592 kBq/animal to additional gamma-irradiation (3 Gy) for testing purposes was evaluated using SCG (Comet assay). A decrease in induction of DNA damage right after additional gamma-irradiation was determined. It correlated with bone marrow cell quantity and the tail length before additional gamma-irradiation. The results support the suggestion about the activation of DNA repair in bone marrow cells under exposure to 90Sr in vivo. 相似文献
84.
Li J Sinoway LI 《American journal of physiology. Heart and circulatory physiology》2002,283(6):H2636-H2643
We examined whether ATP stimulation of P2X purinoceptors would raise blood pressure in decerebrate cats. Femoral arterial injection of the P2X receptor agonist alpha,beta-methylene ATP into the blood supply of the triceps surae muscle induced a dose-dependent increase in arterial blood pressure. The maximal increase in mean arterial pressure (MAP) evoked by 0.1, 0.2, and 0.5 mM alpha,beta-methylene ATP (0.5 ml/min injection rate) was 6.2 +/- 2.5, 22.5 +/- 4.4, and 35.2 +/- 3.9 mmHg, respectively. The P2X receptor antagonist pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid (2 mM ia) attenuated the increase in MAP elicited by intra-arterial alpha,beta-methylene ATP (0.5 mM), whereas the P2Y receptor antagonist reactive blue 2 (2 mM ia) did not affect the MAP response to alpha,beta-methylene ATP. In a second group of experiments, we tested the hypothesis that ATP acting through P2X receptors would sensitize muscle afferents and, thereby, augment the blood pressure response to muscle stretch. Two kilograms of muscle stretch evoked a 26.5 +/- 4.3 mmHg increase in MAP. This MAP response was enhanced when 2 mM ATP or 0.1 mM alpha,beta-methylene ATP (0.5 ml/min) was arterially infused 10 min before muscle stretch. Furthermore, this effect of ATP on the pressor response to stretch was attenuated by 2 mM pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid (P < 0.05) but not by the P1 purinoceptor antagonist 8-(p-sulfophenyl)-theophylline (2 mM). These data indicate that activation of ATP-sensitive P2X receptors evokes a skeletal muscle afferent-mediated pressor response and that ATP at relatively low doses enhances the muscle pressor response to stretch via engagement of P2X receptors. 相似文献
85.
Bruijn LI 《BioTechniques》2002,32(5):1112, 1114, 1116 passim
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88.
Sadek HA Humphries KM Szweda PA Szweda LI 《Archives of biochemistry and biophysics》2002,406(2):222-228
Reperfusion of ischemic myocardial tissue results in an increase in mitochondrial free radical production and declines in respiratory activity. The effects of ischemia and reperfusion on the activities of Krebs cycle enzymes, as well as enzymes involved in electron transport, were evaluated to provide insight into whether free radical events are likely to affect enzymatic and mitochondrial function(s). An in vivo rat model was utilized in which ischemia is induced by ligating the left anterior descending coronary artery. Reperfusion, initiated by release of the ligature, resulted in a significant decline in NADH-linked ADP-dependent mitochondrial respiration as assessed in isolated cardiac mitochondria. Assays of respiratory chain complexes revealed reduction in the activities of complex I and, to a lesser extent, complex IV exclusively during reperfusion, with no alterations in the activities of complexes II and III. Moreover, Krebs cycle enzymes alpha-ketoglutarate dehydrogenase and aconitase were susceptible to reperfusion-induced inactivation with no decline in the activities of other Krebs cycle enzymes. The decline in alpha-ketoglutarate dehydrogenase activity during reperfusion was associated with a loss in native lipoic acid on the E2 subunit, suggesting oxidative inactivation. Inhibition of complex I in vitro promotes free radical generation. alpha-Ketoglutarate dehydrogenase and aconitase are uniquely susceptible to in vitro oxidative inactivation. Thus, our results suggest a scenario in which inhibition of complex I promotes free radical production leading to oxidative inactivation of alpha-ketoglutarate dehydrogenase and aconitase. 相似文献
89.
Falcón LI Cipriano F Chistoserdov AY Carpenter EJ 《Applied and environmental microbiology》2002,68(11):5760-5764
We present data on the genetic diversity and phylogenetic affinities of N2-fixing unicellular cyanobacteria in the plankton of the tropical North Atlantic Ocean. Our dinitrogenase gene (nifH) sequences grouped together with a group of cyanobacteria from the subtropical North Pacific; another subtropical North Pacific group was only distantly related. Most of the 16S ribosomal DNA sequences from our tropical North Atlantic samples were closely allied with sequences from a symbiont of the diatom Climacodium frauenfeldianum. These findings suggest a complex pattern of evolutionary and ecological divergence among unicellular cyanobacteria within and between ocean basins. 相似文献
90.