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31.
ABSTRACT:   Ten lots of common carp and six lots of crucian carp (each lot of 100 fish) were treated under anoxia for five days at water temperatures of 25–31°C. The average per group mortality of common carp was 17%, but none of the 600 crucian carp died. The digestive tract tissues of the common carp that died had significantly lower zinc concentrations than those that survived (59 ± 41 vs 142 ± 60 μg/[g fresh tissue], P  < 0.001). The digestive tract tissues of the crucian carp had mean zinc concentrations of 652 ± 458 μg/(g fresh tissue). One lot of common carp that had low tolerance for anoxia was fed a high zinc diet (2000 mg zinc/kg diet) for 1, 2 or 6 months and then subjected to 5 days anoxia. The survival rates of those fed the high zinc diet 1 and 2 months increased from 0 to 50%, respectively; all of fish that had fed a high zinc diet for 6 months survived. Thus, anoxia survival in common carp and crucian carp is closely related to the high concentrations of zinc in their tissues.  相似文献   
32.
黄瓜霜霉病流行过程的定量分析   总被引:6,自引:0,他引:6  
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33.
Green tea is one of the most-consumed beverages due to its taste and antioxidative polyphenols. However, the protective effects of green tea and its constituent, gallic acid (GA), against kainic acid (KA)-induced seizure have not been studied. We investigated the effect of fresh green tea leaf (GTL) and GA on KA-induced neuronal injury in vivo and in vitro. The results showed that GTL and GA reduced the maximal seizure classes, predominant behavioral seizure patterns, and lipid peroxidation in male FVB mice with status epilepticus (SE). GTL extract and GA provided effective protection against KA-stressed PC12 cells in a dose-dependent manner. In the protective mechanism study, GTL and GA decreased Ca(2+) release, ROS, and lipid peroxidation from KA-stressed PC12 cells. Western blot results revealed that mitogen-activated protein kinases (MAPKs), RhoA, and COX-2 expression were increased in PC12 cells under KA stress, and expression of COX-2 and p38 MAPK, but not RhoA, was significantly reduced by GTL and GA. Furthermore, GTL and GA were able to reduce PGE(2) production from KA-stressed PC12 cells. Taken together, the results showed that GTL and GA provided neuroprotective effects against excitotoxins and may have a clinical application in epilepsy.  相似文献   
34.
Besides cancer prevention, the hypolipidemic effects of tea have been well studied in animals and humans. Recently, statin has been identified in Pu-erh tea extract. Clinical trials have confirmed that statin decreases the incidence of major coronary and cerebrovascular events and this may be due to its hypolipidemic and antiinflammatory effects. Since a good Pu-erh tea needs longer storage (10 years or more) of fermentation to enhance the flavor and fragrance, we screened microorganisms from two Pu-erh teas, 20 and 25 years old. Species of fungi and bacteria strains that contributed to a good taste of Pu-erh tea were isolated. The effect of fermentation was investigated by inoculating fresh tea leaves with individual strains of isolated microorganisms. Results showed that statin, total polyphenol content, and the scavenging activities of alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH) radicals increased during fermentation. Tea leaves inoculated with Streptomyces bacillaris strain R9 had the highest polyphenol content (3.3 mg/100 g) and scavenging ability to DPPH radicals (92%). Streptomyces cinereus strain Y11 was equally good for polyphenol content but yielded the highest amount of statin (1012 ng/g) after 42 days of fermentation. Interestingly, the statin content of fresh tea leaves fermented with strain R9 or Y11 after 180 days was much higher (4- and 8-fold, respectively) than that of the 25-year-old Pu-erh tea (513 ng/g) as measured by the HPLC method. Similarly, these two strains also increased the content of gamma-aminobutyric acid (GABA) 5.7- and 4.7-fold in tea fermented for 180 days as compared with the fresh leaves (1270 microg/g) and that were higher than that of the Pu-erh tea (4900 microg/g). Taken together, the present results indicate that tea short-term fermented with S. bacillaris or S. cinereus enhances the color and content of statin, GABA, and polyphenols.  相似文献   
35.
We studied the link between high zinc levels and the extreme stress tolerance of common carp. Fish under stress showed much higher plasma cortisol levels than controls. Stress or cortisol injection induced large changes in zinc levels in the common carp but not in grass carp, silver carp or tilapia. The effect of 5 days of anoxia and 4 subsequent days of recovery on cortisol and zinc contents in the common carp was investigated. Elevated plasma cortisol resulting from anoxia was correlated with decreased zinc in digestive tract tissue and increased zinc in the head kidney. Zinc was mobilized in the common carp while under stress. Changes in cortisol and zinc contents were reversible during the subsequent recovery from anoxia. Under stress, protein-bound zinc levels increased in the head kidney cell nuclei of common carp as cortisol increased. Zinc and cortisol were bound to the same protein, which was bound to DNA. The protein is likely a glucocorticoid receptor. An increase in immature red blood cells in stressed common carp was observed. Zinc was involved in the stress erythropoiesis response. Zinc may play an important role in stress defense in the common carp via the glucocorticoid receptor.  相似文献   
36.
ABSTRACT:   The distribution of zinc (Zn) concentration in the blood and erythrocytes of common carp, grass carp, silver carp and tilapia was studied. It was found that in whole blood, the average Zn concentrations in these four species of fish (approx. 6–14 μg/[ml whole blood]) were relatively similar to those in other species of fish and mammals. However, the mean Zn concentration in the erythrocytes of common carp is approximately two times higher than the other three species of fish (approx. 5 vs approx. 2 μg/[ml whole blood]). It was found that approximately 70% of the Zn in the common carp whole blood came from its erythrocytes. In addition, approximately 43% of the Zn in the erythrocytes of common carp was found to be located on its outer plasma membranes. When an antibody against a 43 kDa Zn-binding protein, isolated from the digestive tract tissue of common carp, was used, significant quantities of the protein were shown to be present on the erythrocyte plasma membranes of common carp by an indirect immunofluorescent staining. High Zn on the outer plasma membrane of the common carp erythrocyte most probably comes from the 43 kDa Zn-binding protein.  相似文献   
37.
An 8-year-old male Rottweiler was presented for recurrent episodes of dysphagia and vomiting with chronic weight loss. Radiography revealed a mediastinal mass in the heart base region. Necropsy revealed a firm, white mediastinal mass extending along the distal esophagus, through the diaphragm, to the gastric cardia, leftward to the convex visceral aspect of the fundus, and rightward along the lesser curvature of the stomach to the pyloric antrum. The gastric lymph node was enlarged and the omentum contained several nodules. Histologically, deep fundic mucosa contained pleomorphic, vacuolated cells with intracytoplasmic mucin, which was hyaluronidase resistant. Neoplastic cells were cytokeratin positive and vimentin negative. Transmural invasion was evidenced by the presence of cytokeratin-positive cells between smooth muscle bundles of the gastric wall. The mediastinal mass was composed of clusters of neoplastic cells in a stroma of dense and loose connective tissue. Neoplastic cells were also within blood and lymphatic vessels, tracheobronchial and gastric lymph nodes, and around peripheral nerves. This carcinoma most likely arose from the gastric fundus and extended to the cardia, from where it advanced proximally to the mediastinum as well as further rightward along the lesser curvature, demonstrating an anatomic continuity suggestive of a direct invasion. Metastasis, evidenced by the presence of lymphatic, blood, and perineural tumor emboli, also occurred.  相似文献   
38.
Variability in virulence were detected among geographic isolates of Cryphonectria.cubensis (Bruner) Hodges. Inoculation studies of isolates, originally cultured from Brazil, Africa and Hawaii, in provenance of Eucalyptus pellita F. Muell (resistant) and E. saligna Sm. (susceptible) showed that the variation in resistance of Eucalyptus spp. is quantitatively isolate-specific; the variation in virulence quantitatively host-specific. The practical consequences of pathogenic variability of C. cubensis and the strategies of selection and breeding of Eucalyptus for resistance is discussed.  相似文献   
39.
Piper betle, belonging to the Piperaceae family, is a tropical plant, and its leaf and inflorescence are popularly consumed by betel quid (BQ) chewers in Taiwan and many other South and Southeast Asian countries. However, little is known about the biochemical properties of inflorescence Piper betle (IPB) toward reactive oxygen species (ROS) and platelet functions. In the present work, aqueous IPB extract was shown to be a scavenger of H(2)O(2), superoxide radical, and hydroxyl radical with a 50% inhibitory concentration (IC(50)) of about 80, 28, and 73 microg/mL, respectively. IPB extract also prevented the hydroxyl radical induced PUC18 plasmid DNA breaks at concentrations higher than 40 microg/mL. Since ROS are crucial for platelet aggregation, we further found that IPB extract also inhibited the arachidonic acid (AA) induced and collagen-induced platelet aggregation, with an IC(50) of 207 and 335 microg/mL, respectively. IPB extract also inhibited the AA-, collagen- (>100 microg/mL of IPB), and thrombin (>250 microg/mL of IPB)-induced thromboxane B(2) (TXB(2)) production by more than 90%. However, IPB extract showed little effect on thrombin-induced aggregation. These results indicated that aqueous components of IPB are potential ROS scavengers and may prevent the platelet aggregation possibly via scavenging ROS or inhibition of TXB(2) production.  相似文献   
40.
The changes in ionic contents were studied in acidic precipitation samples collected for precipitation events in Taipei, which is near the sea. The storage cases under investigation include filtration, refrigeration, and light. Thus the experimental design leads all precipitation samples collected in the same rain event stored under different conditions. They were then analyzed six times successively within two months to provide the information containing potential ionic composition change. The measured constituents are H+, K+, Na+, Ca2+, Mg2+, NH4 +, NO3 ?, SO4 2?, and Cl?. The comparison of measured ionic concentrations corresponding to different storage methods yield no significant difference. The increases of NO3 ? and decreases of NH4 + with time were observed to be of similar magnitude, while the variation of pH values is significant. The presented study indicated the important role played by sample storage in determining the ionic composition of precipitation samples.  相似文献   
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