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91.
The metabolism, uptake and translocation of paraquat in resistant (R) and susceptible (S) biotypes of Crassocephalum crepidioides (Benth.) S. Moore (redflower ragleaf) at the 10-leaf stage was investigated. A study on the properties of leaf surface was carried out to examine the relationship between leaf surface characters and paraquat absorption. The extractable paraquat was not metabolized by the leaf tissue of either the resistant or susceptible biotypes. Differential metabolism, therefore, does not appear to play a role in the mechanism of resistance. Both biotypes did not show any significant difference in the amount of cuticle and trichome densities. Furthermore, both biotypes are identical in the structure of stomata, trichomes and epicuticular wax. The results of the leaf surface studies are in agreement with the findings of the uptake study. Both biotypes demonstrated no significant difference in absorption between the resistant and susceptible biotypes. However, 10% of the absorbed 14 C-paraquat into the S biotype was translocated basipetally, but not in the R biotype. The results of this study suggest that in C. crepidioides , differential translocation may contribute to the mechanism of resistance at the 10-leaf stage. 相似文献
92.
Doris Van Der Krol Ingolf Schuphan Brigitte Thiede Burkhard Schmidt 《Pest management science》1995,45(2):143-152
By means of standardized procedures, the metabolism of [ring-2,6-14C]-parathion was investigated in carrot (Daucus carota L.), purple foxglove (Digitalis purpurea L.), soybean (Glycine max Merrill cv. ?Mandarin’?, and Glycine max Merrill cv. ?Harosoy 63’? cultivated on B5 and Miller media, respectively), thorn apple (Datura stramonium L.), and wheat (Triticum aestivum L.) cell suspension cultures. In the wheat and soybean (Mandarin) cells only 2.9 and 8.9%, respectively, of the applied parthion remained unmetabolized after 48 h of incubation, while 51.2, 57.9, 60.3, and 62.4% of the unchanged parent were detected in the D. purpurea, D. Stramonium, carrot and soybean (Harosoy) cultures, respectively. In all suspensions, paraoxon and 4-nitrophenol were found as phase I metabolites, thus demonstrating that plant tissues can catalyse oxidative desulfuration and dearylation of parathion. 4-Nitrophenol was also glycosylated with glucose and possibly galactose. Further, as yet unidentified, metabolites indicated that bio-transformations had also occurred at the aromatic moiety. Large amounts of non-extractable residues were detected in the wheat suspension (38.3%), while the other cultures showed a lower incorporation of 14C into insoluble cell material (0.9-9.4%). For a prospective ecotoxicological evaluation of the metabolic fate of pesticides and xenobiotics in plants in general, the differential metabolic capacity of plant cell cultures and plants should be taken into account. 相似文献
93.
Scott J. Nissen Robert A. Masters W. Mack Thompson Robert N. Stougaard 《Pest management science》1995,45(4):325-329
Imazapyr absorption, translocation, root release and metabolism were examined in leafy spurge (Euphorbia esula L.). Leafy spurge plants were propagated from root cuttings and [14C]imazapyr was applied to growth-chambergrown plants in a water + 28% urea ammonium nitrate + nonionic surfactant solution (98.75 + 1 + 0.25 by volume). Plants were harvested two and eight days after herbicide treatment (DAT) and divided into: treated leaf, stem and leaves above treated leaf, stem and leaves below the treated leaf, crown, root, dormant and elongated adventitious shoot buds. Imazapyr absorption increased from 62.5% 2 DAT to 80.0% 8 DAT. Herbicide translocation out of the treated leaf and accumulation in roots and adventitious shoot buds was apparent 2 DAT. By the end of the eight-day translocation period only 14% of applied 14C remained in the treated leaf, while 17% had translocated into the root system. Elongated and dormant adventitious shoot buds accumulated 3.2- and 1.8-fold more 14C, respectively, 8 DAT than did root tissue based on Bq g?1 dry weight. Root release of 14C was evident 2 DAT, and by 8 DAT 19.4% of the 14C reaching the root system was released into the rooting medium. There was no metabolism of imazapyr in crown, root or adventitious shoot buds 2 DAT; however, imazapyr metabolism was evident in the treated leaf 2 and 8 DAT. Imazapyr phytotoxicity to leafy spurge appears to result from high imazapyr absorption, translocation to underground meristematic areas (roots and adventitious shoot buds), and a slow rate of metabolism. 相似文献
94.
Lechowski R Bielecki W Sawosz E Krawiec M Kluciński W 《Veterinary research communications》1999,23(1):1-14
Sixty-four Wistar rats were divided into 8 equal groups and kept for 36 days in individual boxes. Three of the groups were given full synthetic diets containing various animal fats: beef tallow, pork fat or fish oil. A control group was fed the diets without the fat. The other four groups were fed the same diets with lecithin supplementation. At the end of experiment, sections taken from the liver were stained with haematoxylin–eosin and Sudan III to indicate fat infiltration. Liver enzyme levels, total bilirubin, albumin and two products of lipd metabolism were measured in serum from all the animals. The addition of lecithin to the diets did not influence the level of enzymes in the serum except in rats fed the diet containing beef tallow. A relationship between the type of diet, lecithin supplementation and the total cholesterol concentration in serum was observed. The concentration of HDL-cholesterol was only influenced by lecithin supplementation and that of triglycerides by the type of fat in the diet. The addition of lecithin to the diet was associated with proliferation of Kupffer cells, and an increased number of binuclear cells. Fatty degeneration of hepatocytes was less pronounced in all groups following lecithin supplementation. Lecithin supplementation of the diet did not elicit any pathological lesions and may be considered as a hepatocyte protector. This favourable effect of lecithin was most marked in the group of rats fed the fish oil. 相似文献
95.
Bone mineral changes in growing, pregnant and lactating cattle 总被引:1,自引:0,他引:1
R Zetterholm 《Acta veterinaria Scandinavica》1978,19(1):18-29
Bone mineral content (BMC) was determined in one or two coccygeal vertebrae by dichromatic photon absorptiometry in two sets of cattle: A. This set consisted of six fattening bulls. Their increases of BMC and weights were closely correlated. However, BMC increased slightly more than weight. B. There were 28 cows in this set. BMC was measured during lactation and pregnancy. It was found that BMC increased during the dry period and decreased during early lactation. There were great individual variations in BMC, and the skeletal turnover seemed to be great. 相似文献
96.
97.
抗旱性不同的苹果属植物水分胁迫下核酸代谢及自由基变化 总被引:8,自引:3,他引:5
水分胁迫引起苹果属植物中抗旱性较弱的平邑甜茶和抗旱性较强的新疆野苹果幼苗叶片相对含水量(RWC) 、DNA、RNA 含量下降, O2-·、H2O2 含量增高, DNase、RNase 活性上升; 其中DNA 含量下降的幅度小于RNA , DNase 活性上升的幅度小于RNase。抗旱性较强的新疆野苹果在水分胁迫下幼苗叶片的RWC、DNA、RNA 含量下降的幅度以及O2-·、H2O2含量增高、DNase、RNase 活性上升的幅度均小于抗旱性较弱的平邑甜茶。水分胁迫下平邑甜茶和新疆野苹果幼苗叶片的DNA、RNA 含量与RWC、O2-·、H2O2 含量和DNase、RNase 活性间均呈显著相关。 相似文献
98.
Capece BP Castells G Pérez F Arboix M Cristòfol C 《Veterinary research communications》2000,24(5):339-348
Benzimidazole anthelmintic drugs are widely used in veterinary practice. Albendazole sulphoxide (ABZSO) is a benzimidazole drug with two enantiomers, as a consequence of a chiral centre in the sulphoxide group. The kinetics of these enantiomers were studied in male and female sheep. Plasma samples were obtained from the animals between 0.5 and 72 h after oral administration of 7.5 mg/kg of a racemic formulation of ABZSO (total-ABZSO). After a liquid–liquid extraction, the samples were analysed by HPLC to determine the concentrations of total-ABZSO and of the sulphone metabolite (ABZSO2). During the chromatographic analysis, the ABZSO peak was collected and reanalysed by an HPLC technique using a Chiral AGP column to quantify the enantiomeric proportion therein. After kinetic analysis, the AUCs obtained for the (+)-ABZSO were 5.8 and 4.0 times higher than those for the (–)-ABZSO in male and female animals, respectively. The mean residence times were 23.4 and 16.1 h for (+)-ABZSO and 22.2 and 17.4 h for (–)-ABZSO for male and female animals, respectively. The only significant difference between the sexes (p<0.05) was in the T
max of the (–)-ABZSO. Comparing both enantiomers within each sex, significant differences were found in all the kinetic parameters. Finally, no kinetic differences were found between sex for total-ABZSO or ABZSO2. 相似文献
99.
100.
鱼类主要内分泌激素和蛋白质代谢的关系 总被引:1,自引:0,他引:1
本文就鱼类主要的内分泌激素(T3、T4、GH、IGF-Ⅰ)对蛋白质代谢的调控以及饲料蛋白质质量和数量对鱼类内分泌激素分泌的调控进行概述。 相似文献