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排序方式: 共有127条查询结果,搜索用时 15 毫秒
1.
Régis Moreau Sadasivam J. Kaushik Konrad Dabrowski 《Fish physiology and biochemistry》1996,15(5):431-438
A study was conducted to evaluate tissue storage and mobilisation of L-ascorbic acid (AA) in the Siberian sturgeon (Acipenser baeri) fed three different experimental diets. The three treatments consisted of a diet devoid of vitamin C (diet A0) and two diets supplemented with equivalent of 300 mg AA kg–1 in the form of either silicone-coated ascorbic acid (diet SC) or of ascorbyl-2-polyphosphate (diet AP). During the first phase (4 months) of the trial, six batches of 130 Siberian sturgeon (initial body weight: 25.5±0.5 g) each were fed one of the three diets in duplicate. During the second phase (3 months), fish from groups SC and AP were switched to diet A0 and those fed diet A0 during the first phase were switched to diet SC. Irrespective of the dietary treatment, growth rates were not significantly different from each other. At the end of phase I, in all tissues studied, total ascorbic acid (TAA) concentrations were higher in Siberian sturgeon fed diet AP than in the other two groups. During phase II, tissue ascorbate depletion was also higher in the AP group than in the other two groups. Transfer of the AA-free diet fed group onto a diet supplemented with 300 mg AA kg–1 (diet SC) led to a slight increase in the TAA concentrations in all tissues. Blood plasma tyrosine concentrations were not significantly different between the three groups. Whole-body collagen levels were affected by dietary AA levels or forms at the end of phase I; the differences were not significant at the end of phase II. Muscle collagen levels were slightly affected. L-Gulonolactone oxidase activity was found in the kidney of Siberian sturgeon, but not in the liver. The ascorbyl-2-polyphosphate appears to be either better utilised by Siberian sturgeon, like in many other teleosts, or more stable than the silicone-coated AA during food processing and storage. Presence of L-gulonolactone oxidase activity in Siberian sturgeon kidney combined with the absence of gross scorbutic signs in AA-free diet fed groups expressing very good growth rates suggested no need of dietary AA byA. baeri. 相似文献
2.
Photochemical stability of the insecticide, quinalphos (O,O-diethyl O-quinoxalin-2-yl phosphorothioate), adsorbed on kaolinite and palygorskite was studied. In all cases considerable photostabilization was achieved in comparison with the sample of pesticide in its free form. Improvement of photostabilization was achieved when a cationic dye (crystal violet) was co-adsorbed with the quinalphos. The interactions between quinalphos and clays were studied by Fouriertransform infra-red spectroscopy. It is suggested that photostabilization is due to steric hindrance imposed by the clay surface to the isomerization step of photochemical reaction and pacification of clay surface by crystal violet. 相似文献
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Sadasivam J. Kaushik 《Fish physiology and biochemistry》1986,2(1-4):131-140
Both external and internal factors affect the response of fish to variations in dietary quantity and quality. An attempt is made to review major, recent studies on the series of intermediate steps (intake, digestion, metabolism, excretion and retention) involved in the global response of fish to environmental changes. Among these external factors, greater attention is however devoted to those that are the most important natural effectors within the aquatic environment: temperature, ambient oxygen and salinity. The changes brought about by a change in temperature at different levels of nutrient utilization have been studied to a great extent in the recent past. As temperature affects in the first instance, the voluntary food intake, a discussion on current nutrient requirement data should preferably be dealt with in absolute terms. While critical levels of oxygen below which growth is hindered are sufficiently defined for many species, precise data on the direct effects of oxygen deficiency on nutrient utilization are still fragmentory. With regard to salinity, a distinction between stenohaline and euryhaline species and a knowledge of the physiological mechanisms corresponding to their life cycles are required before attempting comparative analyses. Within euryhaline species, best performances are noted at salinities isotonic to the internal medium. Despite accumulating evidence on the effects of cyclical phenomena, the chronobiological approach to fish culture remains practically unexplored. 相似文献
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Amit Kaushik Navinder Saini Sunita Jain Poonam Rana R.K. Singh Rajinder K. Jain 《Euphytica》2003,134(2):231-238
Segregation for salinity tolerance and ISSR markers based molecular polymorphism were investigated in a F3 plant population raised via single-seed descent method from a cross between salt-tolerant indica rice variety CSR10 and salt-susceptible
premium traditional Basmati rice variety Taraori Basmati HBC19. A total of 130 F3plants were evaluated individually for salinity tolerance on 1–9 scale on the basis of seedling growth parameters; the average
score ranged between 1.7 to 8.3. Frequency distribution curve obtained using the salinity tolerance data of F3 population and a chi-square analysis, showed a good fit to a normal distribution. Eleven plants each in the category of salt-tolerant
and salt-susceptible were selected from the segregating F3 population for ISSR marker analysis. A total of 149 bands (4–11 bands per primer) ranging from 200 to 3530 bp were scored
for the two rice varieties and the selected CSR10 × HBC19 segregating F3 plants using 26 ISSR primers. Of these, 89 were monomorphic and 60 were polymorphic. Of the 60 polymorphic bands,36 and 20
bands were specific to CSR10 andHBC19 respectively. The remaining four bands were amplified using UBC primers 810,848, 853
and 886 and present in only some of the CSR10 × HBC19 F3 plants. Notably, ISSR primers with dinucleotide repeat motif and 5'-anchored end amplified more number of bands (7.0 bands/primer)
compared to3'-anchored dinucleotide primers (5.4bands/primer), but 3'-anchored dinucleotide primers revealed higher level
of polymorphism (2.6 polymorphic bands/primer) compared to 5'-anchoreddinucleotide primers (1.43 polymorphic bands/ primer).
While distribution of majority of the polymorphic bands were more or less in the expected ratios in salt-tolerant and/or salt-sensitive
F3segregating plants, but some of the bands amplified using UBC ISSR primers 823, 825,826, 849, 853, 864, 866 and 884 showed
highly skewed distribution. Such polymorphic bands stand greater chances of having a linkage with the genes/ QTLs for salinity
tolerance and shall be the target for further studies.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
10.
Rain water samples were regularly collected from three sites, namely, Netaji Nagar, Moti Nagar and Town Hall within the Delhi city area from July, 1980 to June, 1982. The pesticide residues were adsorbed on polyurethane foam coated with 0.5 % DC-200 and subsequently extracted and analyzed for DDT, HCH and their metabolites/isomers. The concentration of total DDT ranged from 0.22 to 108 μg L?1 with a mean value of 12.5 μg L?1. The samples of rain water contained varying levels of 4,4-DDT, 2,4-DDT, 4,4-DDE, and 4,4-DDD. The 4,4-DDT, 4,4-DDE and 2,4-DDT were the main components of total DDT. The range of HCH residues in rain water was from 0.08 to 43 μg L?1 with a mean of 5.3 μg L?1. The residues of HCH consisted mainly of α- and γ-isomers with traces of β and δ-isomers. The α- and γ-isomers accounted for 76 and 24% of total HCH, respectively. The concentrations of DDT and HCH in rain water were generally less than 10 μg L?1 and exceeded 10 in only 4 and 3 cases, respectively. The residues of these insecticides were generally higher during October to December. Residues of DDT were higher at Moti Nagar which is near a DDT factory. Residues of HCH were maximum at Town Hall, a commercial area of the city. 相似文献