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101.
The changes in transport activity of tonoplast proton pumps under the influence of exogenous NO donator and modulation of Ca2+ concentration jointly and separately were investigated at different stages of ontogenesis and under hyperosmotic stress. The results suggest that both exogenous NO donator and Ca2+ ions can influence the activity of transport processes related to tonoplast and this influence is especially evident in the period of growth and accumulation of metabolites. Under hyperosmotic stress, H+-pyrophosphatase plays a more important role than H+-ATPase: the activity of the former increases 2.3-fold compared to the control osmotic conditions, whereas the activity of H+-ATPase is practically unchanged. H+-pyrophosphatase was more responsive to the presence of exogenous NO donator and to variations in Ca2+ concentration. The effects of exogenous NO donator on tonoplast proton pumps depended on the concentration of Ca2+, which apparently can mediate NO action.  相似文献   
102.
The sequential cytological events of the regeneration process, after partial excision of the gastrocnemius muscle in the rat, were followed by light and electron microscopy. During the first 2 days after injury leukocytes and macrophages infiltrate into the traumatized area. Myogenic regeneration is then characterized by mainly two repair mechanisms. Mononucleated cells, that populate the excised area, most probably fuse together to give rise to newly formed multinucleated myotubes that further develop to striated myofibers. Another mechanism involves the repair of injured muscle fibers by the possible fusion of mononucleated cells with their necrotic cut ends. Consequently, by addition of nuclei and new muscular material, sarcoplasmic outgrowths from the injured fibers are formed. It is concluded that mainly two repair mechanisms are involved in the regeneration process following partial excision of a muscle: addition of new muscle fibers in a process similar to that of embryonic myogenesis and also meristic growth from the injured fibers.  相似文献   
103.
Study of serial semi-thin (0.5 micron) metacrylate and paraffinic (8 microns) of rat kidney sections 6, 12, 24 and 48 h after subcutaneous injection of mercury bichloride at a dose of 0.6 mg/100 g bw has revealed that injury to different parts of the canalicular nephron is of heterogeneous character. The proximal part of the nephron demonstrates both complete and partial necrosis of nephrocyte cytoplasm. The distal parts of the nephron and collecting tubules are characterized by partial necrosis of the apical cytoplasm. Within the period between 12 and 24 h after the mercury bichloride injection, intracellular reparative processes are observed, in addition to destruction, in partially damaged but viable nephrocytes, which is confirmed by the enlargement of the nucleolic size. Regeneration of the tubular epithelium due to cellular restoration was unmarked 24 h after the mercury bichloride injection.  相似文献   
104.
Antagonism by theophylline of respiratory inhibition induced by adenosine   总被引:6,自引:0,他引:6  
The effects on respiration of an analogue of adenosine, L-2-N6-(phenylisopropyl)adenosine (PIA), and of the methylxanthine, theophylline, were determined in 19 vagotomized glomectomized cats whose end-tidal PCO2 was kept constant by means of a servo-controlled ventilator. Integrated phrenic nerve activity was used to represent respiratory output. Our results show that PIA, whether given systemically or into the third cerebral ventricle, depressed respiration. Systemically administered theophylline stimulated respiration. Theophylline given intravenously, or into the third ventricle not only reversed the depressive effects of previously administered PIA but caused further increases of respiration above the control level. Prior systemic administration of theophylline blocked both respiratory and hypotensive effects of subsequently administered PIA. Effects of either agent on medullary extracellular fluid pH did not explain the results. We conclude that the adenosine analogue PIA, acts to inhibit neurons in the brain that are involved in the control of respiration and that its effects are blocked by theophylline. We suggest that adenosine acts as a tonic modulator of respiration and that theophylline stimulates breathing by competitive antagonism of adenosine at neuronal receptor sites.  相似文献   
105.
The gene encoding the circumsporozoite (CS) protein of the rodent malaria parasite Plasmodium berghei was cloned and characterized. A cDNA library made from P. berghei sporozoite RNA was screened with a monoclonal antibody for expression of CS protein epitopes. The resulting cDNA clone was used to isolate the CS protein gene from a lambda library containing parasite blood-stage DNA. The CS protein gene contains a central region encoding two types of tandemly repeated amino acid units, flanked by nonrepeated regions encoding amino- and carboxy-terminal signal and anchorlike sequences, respectively. One of the central repeated amino acid unit types contains the immunodominant epitopes.  相似文献   
106.
The authors studied the anabolic effect of peptide morphogen of the hydra undecapeptide on normal and regenerating rat liver. Ornithine decarboxylase (EC 4.1.1.17) activity served as a marker. Intraperitoneal injection of the peptide into intact animals stimulated ornithine decarboxylase activity in a dose-dependent manner. In partially hepatectomized rats the peptide stimulated ornithine decarboxylase activity in the dose of 20 micrograms/kg body weight while greater doses inhibited the enzyme activity.  相似文献   
107.
108.
Eleven males with XLP were evaluated for EBV-specific antibodies during periods of 2 to 7 yr. Variable responses to EBV-specific antigens were found. All 11 patients had subnormal anti-EBNA titers, which probably reflected a T cell deficiency. The patients showed four different patterns in their anti-VCA response: 1) two boys who had experienced malignant lymphoma mounted no antibodies at all; 2) two patients showed intermittent anti-VCA titers; 3) four males had persistently elevated anti-VCA titers; and 4) three patients showed normal anti-VCA titers. ADCC against EBV-infected cells was abnormally low in six patients and was elevated in two patients given gamma-globulin. ADCC titers did not correlate with anti-VCA titers. However, most patients with XLP failed to effect regression of autologous EBV-infected lymphoblastoid cell lines, indicating a deficiency in long-lived T cell-mediated immunity to EBV.  相似文献   
109.
Peptide material has been first isolated from k-casein pepsin hydrolysate. Its subcutaneous injection to hungry animals induced high amplitude (250-350 mV) and high frequency (16-20 Hz) oscillations of electrical potentials usually observed in food satiety and cholecystokinin administration. The peptide reduced respiratory and to a lesser extent heart rate. Its effect is temporary eliminated by naloxone. According to an aminogram, the peptide is a fragment of para-k-casein. A neurotropic peptide effect is connected with satiety regulation and milk consumption in the postnatal period.  相似文献   
110.
3H-labeled Acholeplasma DNA probes were generated in vitro by the nick-translation method and used to determine the nucleotide sequence homology among the type strains of the eight currently recognized species of Acholeplasma. Very little nucleotide sequence homology (less than or equal to 18%) was found among the eight species, with heteroduplexes showing at least 12% or more mismatching as determined by thermal elution midpoints. The small amount of nucleotide sequence homology among the eight species indicates that these species are quite distinct and are not closely related to each other genomically.  相似文献   
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