张北县农业可持续发展对策研究

通过对张北县土地利用现状的调研与评价及其农业中存在问题的分析,提出了该地区农业可持续发展的对策,对促进土地综合整治、农业结构调整与优化以及国民经济持续发展具有重要的现实意义。     

Comparison of tiletamine-zolazepam-ketamine and tiletamine-zolazepam-ketamine-xylazine anaesthesia in sheep

Summary The anaesthetic effects of intravenous tiletamine-zolazepam 6.6 mg/kg-ketamine 6.6 mg/kg (TK) and tiletamine-zolazepam 6.6 mg/kg-ketamine 6.6 mg/kg-xylazine 0.11 mg/kg (TKX) were evaluated in six wethers. Heart rate, respiration rate, arterial blood pressure, and the electrocardiogram were monitored during anaesthesia. Analgesia was tested by electrical stimulation in the left flank. Atropine (0.03 mg/kg) was given intramuscularly before induction, but after recording of baseline heart rate and respiratory rate. The duration of analgesia was 28.7 ± 6.9 min with TK and 82.8 ± 26.6 min with TKX. Heart rate increased significantly within 5 min after TK or TKX administration. Respiratory rate remained unchanged after TK administration, but increased significantly from 5 to 45 min after TKX administration. Arterial blood pressure decreased significantly at 15 min with TK and 30 min with TKX. Sheep remained recumbent for 201 min with TK and 166 min with TKX. All recovered uneventfully. We conclude that either TK or TKX may be used for anaesthetising sheep.     

Metabolism of O,O-dimethyl S-[α-carboethoxy)benzyl]phosphorodithioate (phenthoate) in the white mouse and house flies

The metabolism of O,O-dimethyl S-[α-(carboethoxy)benzyl]phosphorodithioate (phenthoate), an organophosphorus insecticide of low mammalian toxicity, was investigated in white mice and in susceptible and resistant strains of house flies. Phenthoate was metabolized rapidly in the mouse to a wide variety of detoxication products and only an insignificant amount of phenthoate oxon was detected. The same detoxication products were produced in house flies but, compared to the mouse, substantial amounts of phenthoate oxon also were found. The selective toxicity of phenthoate between insect and mammal is attributable to the difference in the accumulation of the oxon.     

The purification and characterization of esterases from insecticide-resistant and susceptible house flies

Four major esterases in one susceptible (CSMA) and two resistant (Hirokawa, E₁) house fly strains were separated by chromatofocusing. Of the four esterases, those with pI's of 5.1 and 5.3 accounted for 90% of the p-nitrophenyl butyrate hydrolyzing activity in the three house fly strains. They also accounted for 70% (Hirokawa, E₁) and 40% (CSMA) of the paraoxon-hydrolyzing activity as well as 87% (Hirokawa), 39% (E₁) and 66% (CSMA) of the malathion-hydrolyzing activity in microsomes as measured by esterase-antibody interaction. In the Hirokawa strain, the pI 5.1 esterase was the predominant esterase and was more active than that of the the CSMA strain. Different substrate specificities and a different K_m toward acetylthiocholine, as well as different rates of malathion and paraoxon hydrolysis between the Hirokawa and CSMA strains, suggest a qualitative difference in the pI 5.1 esterase. For the pI 5.1 esterase from the E₁ strain, a different substrate specificity, a different K_m for p-nitrophenyl butyrate, a different sensitivity to inhibitors, and a different rate of paraoxon hydrolysis suggest that it is a modified esterase. This esterase is not a phosphorotriester hydrolase, nor does it lack nonspecific esterase activity. It is a modified esterase which has a different substrate specificity when compared to the esterases from the other strains. The molecular weight of the esterases studied was approximately 220,000, with pH optima of about 7.0.The ratio of malathion α-monoacid to β-monoacid formation was about 9.0 for the pI 5.1 and 5.3 esterases and 1.5 for the pI 4.8 and 5.6 esterases. The existence of a higher $\text{α}\text{β}$ ratio for the pI 5.1 and 5.3 esterases and their significant rate of malathion hydrolysis in the Hirokawa strain indicate that an increase in the $\text{α}\text{β}$ ratio in house flies reported was due to the increase in the pI 5.1 esterase in the resistant strain.     

The Anti‐Müllerian Hormone Profile is Linked with the In Vitro Embryo Production Capacity and Embryo Viability after Transfer but Cannot Predict Pregnancy Outcome

The current study investigated the possibility of using the AMH concentration as a predictor of the ability of Korean Hanwoo cows to produce cumulus‐oocyte complexes, embryos that survive after transfer as well as the pregnancy outcome of surrogates. Eight sessions of ovum pick‐up (OPU) were performed with 19 donor cows at an interval of 3–4 days. Antral follicle count (AFC), oocyte quality and in vitro embryo development were recorded for each cow. Embryos produced from cows with different AMH profiles were transferred into recipients (n = 96). Cows in the high (≥0.25 ng/ml) and intermediate (0.1≥ to <0.25 ng/ml) AMH groups had a significantly higher AFC per OPU session (20.40 ± 1.36 and 16.91 ± 1.52, respectively; mean ± standard deviation) than cows in the low AMH group (<0.1 ng/ml; 12.19 ± 2.14). In addition, more cumulus‐oocyte complexes per donor were recovered in the high (11.46 ± 1.22) and intermediate (7.38 ± 0.83) AMH groups than in the low AMH group (4.77 ± 0.44). The percentage of oocytes reached blastocyst stage was significantly higher in the intermediate (47.0%) and high (38.5%) AMH groups than in the low AMH group (32.3%). The number of embryos produced per cow was higher in the high (3.9 ± 0.2) and intermediate (6.9 ± 0.6) AMH groups than in the low AMH group (2.2 ± 0.3). The percentage of embryos that gave birth to viable calves when transferred into recipients was higher for those derived from cows in the intermediate AMH group (50.7%) than for those derived from cows in the low (35.7%) and high (36.4%) AMH groups. In conclusion, a single measurement of AMH concentration predicted the in vitro embryo production potential of donor Korean native cows before OPU and is linked with embryo viability after transfer into recipients.     

Effect of water-to-bean ratio on the contents and compositions of isoflavones in tofu

The present study investigated the changes of the bioavailable isoflavones, including daidzin, genistin, daidzein, and genistein, during the making of tofu. The amount of extracted daidzin and genistin in soy milk increased with increasing water-to-bean ratios from 5 to 9 and reached the maximum level at the ratios of 9-11. On the other hand, the amount of extracted free isoflavones (daidzein and genistein) was not affected by the water-to-bean ratio at the range of 5-11, and their extracted amounts in soy milk were 2-4-fold those in raw soybean. It is suggested that these free isoflavones are mainly derived from daidzin, genistin, malonyldaidzin, and malonylgenistin through enzymatic hydrolysis during the making of soy milk. Tofu made with water-to-bean ratios of 9:1 and 10:1 had the maximal retentions of daidzin and genistin, which were due to the fine homogeneous network microstructure that is supposed to be more effectively retained through hydrophilic interaction with protein. On the contrary, the retained amount of free isoflavones decreased significantly as the water-to-bean ratio increased from 7 to 11, due to their weakening hydrophobic interaction with protein. In this study it was found that the homogeneous microstructure of tofu improved the retention of hydrophilic daidzin and genistin and that the increased amount of drained water does not significantly reduce their retention in the final tofu products as generally imagined.     

Anti-inflammatory effects of isoflavone powder produced from soybean cake

Soybean cake, a byproduct obtained during the processing of soybean oil, has been shown to be a rich source of isoflavones. The objectives of this study were to use soybean cake as raw material for processing into powder and to evaluate the anti-inflammatory activity. Eleven treatments, including powders of malonylglucoside, glucoside, acetylglucoside, aglycone, ISO-1, and ISO-2, as well as genistein standard, gamma-PGA, control, normal, and PDTC, were used for evaluation. A total of 77 mice were each provided daily with tube feeding for 4 weeks at a dose of 0.3 mL of aqueous solution from each treatment, and inflammation was induced with intraperitoneal injection of 1 mg/kg of body weight lipopolysaccharide (LPS). Results showed that all of the isoflavone powders and genistein standard were effective in inhibiting LPS-induced inflammation, lowering leukocyte number in mice blood and reducing production of IL-1beta, IL-6, NO, and PGE2 in both peritoneal exudate cell supernatant and peritoneal exudate fluid. All of the isoflavone treatments failed to retard T cell proliferation; however, both ISO-1 and ISO-2 could inhibit B cell proliferation. The difference in anti-inflammatory activity was minor between any of the isoflavone treatments.