反刍动物脲酶抑制剂的研究进展

尿素作为非蛋白氮饲料直接饲喂动物 ,在瘤胃中分解速度快于微生物利用速度 ,这不仅降低尿素利用效率 ,而且容易造成氨中毒。脲酶抑制剂可以降低尿素的分解速度 ,提高尿素利用效率。文章就目前国内外各种瘤胃脲酶抑制剂对动物瘤胃尿素分解速度、氨浓度、营养物质利用及对动物生产性能的影响进行了综述。     

不同热处理对黑豆干物质消化率,蛋白质消化率的影响

为了研究热处理的温度和时间对黑豆干物质消化率(DMD)、蛋白质消化率(PD)及脲酶活性的影响规律,对经过110℃和121℃下分别处理3,9和15min的饲用黑豆进行了离体干物质消化率和离体蛋白质消化率及脲酶活性的测定。结果表明:在121℃处理15min的样本干物质消化率和蛋白质消化率最高,分别为75.13%,90.91%,脲酶活性最低,为0.04mg/min·g。作者认为:在本研究范围内,湿热处理最适宜的温度是121℃,时间是15min。     

信号转导抑制剂对囊素刺激杂交瘤细胞抗体分泌及其mRNA表达的影响

以杂交瘤细胞为模型 ,在培养液中加入不同的信号转导抑制剂和囊素 ,用间接ELISA法测定抗体分泌水平 ,用定量RT PCR法检测抗体mRNA的表达水平。结果表明 ,加入Gα 蛋白选择性抑制剂NF 0 2 3、蛋白激酶C抑制剂GF10 92 0 3X、磷脂酰肌醇 3激酶抑制剂heparin、Ca2 /calmodulin依赖蛋白激酶Ⅱ抑制剂KN 6 2、磷脂酶C抑制剂U 7312 2和蛋白激酶G抑制剂后 ,囊素对杂交瘤细胞抗体分泌速度的影响明显 (P <0 0 1)。而加入蛋白激酶A抑制剂 4 Cyano 3 M thylisoquinoline、酪氨酸蛋白激酶抑制剂 genistein和丝裂原活化的蛋白激酶抑制剂PD 980 5 9后 ,囊素对杂交瘤细胞抗体分泌速度的影响不明显 (P >0 0 5 ) ,这 3种抑制剂对杂交瘤细胞抗体分泌速度的抑制率分别为 74 5 5 % ,91 13%和80 6 9%。加入 4 Cyano 3 M thylisoquinoline、genistein和PD 980 5 9后 ,囊素处理组与对照组γ1mRNA的表达水平差异不显著 (P >0 0 5 ) ,说明这 3种抑制剂阻断了囊素刺激的杂交瘤细胞抗体mRNA的表达。以上结果表明 ,蛋白激酶A、酪氨酸蛋白激酶和丝裂原活化的蛋白激酶参与了囊素在杂交瘤细胞中的信号转导。     

几丁质合成抑制剂类杀虫剂的发展和应用

本文重点介绍了苯酰基脲类、噻嗪酮这两类几丁质合成抑制剂类杀虫剂的发展概况和应用的有关杀虫特性及其目前在防治几类农作物害虫方面的应用情况,分析了其在应用方面的主要问题,并对其前景进行了讨论。     

植物源血管紧张素转换酶抑制剂的研究进展

血管紧张素转换酶抑制剂(Angiotensin converting enzyme inhibitors,ACEI)通过肾素-血管紧张素系统(RAS)和激肽释放酶-肽酶系统(KKS),抑制血管紧张素II的生成,减少缓激肽的降解,从而达到降血压的目的;植物来源的天然化合物具有来源广泛、结构多样、特异性高、毒性低等特点,因而从植物中筛选安全有效的ACEI成为研究热点。在此综述了血管紧张素转换酶(ACE)的活性测定方法以及植物来源的不同结构类型的ACEI研究进展。     

杂草对光系统Ⅱ抑制剂的抗药性研究进展

随着除草剂使用量和使用频率的不断增加,杂草抗药性问题也逐渐成为杂草防除及治理的难点和热点。目前杂草对PS(Photosystem)Ⅱ抑制剂类除草剂产生抗药性主要分为靶标抗性和非靶标抗性。本研究综述了近年来杂草对PSⅡ抑制剂类除草剂抗药性的产生、发展现状及杂草抗PSⅡ抑制剂类除草剂的机理。针对这些问题,提出除草剂使用过程中需要注意的事项,为延缓杂草对该类除草剂产生抗药性提供一定参考。     

黑龙江省稻稗对丁草胺的抗性测定及交互抗性的研究

【目的】明确黑龙江省水田稻稗(Echinochloa oryzicola Vasing)对丁草胺的抗药性水平以及对其他细胞分裂抑制剂的交互抗药性水平。【方法】采用琼脂法和整株盆栽法测定了黑龙江省14个地区53个田块的稻稗对丁草胺的抗药性以及对其他3种细胞分裂抑制剂丙草胺、苯噻酰草胺和莎稗磷的交互抗性。【结果】琼脂法检测出庆安03、东京城镇02等4个稻稗生物型对丁草胺产生了中等水平抗性，抗性指数为12.92~26.03，占供试稻稗生物型的7.55%；兴隆镇03、阿城04等4个稻稗生物型对丁草胺产生了低等水平抗性，抗性指数为6.63~8.86，占供试稻稗生物型的7.55%；庆安01、汤原01等5个稻稗生物型对丁草胺敏感性下降，抗性指数为3.18~4.84，占供试稻稗生物型的9.43%；其余阿城02、尚志02等40个稻稗生物型对丁草胺表现敏感，抗性指数均小于3，占供试稻稗生物型的75.47%。选取上述测定结果当中抗性最高的两个生物型，使用整株盆栽法进行对丁草胺的抗性水平验证。发现庆安03和东京城镇02同样产生了中等水平抗性，抗性指数分别为16.78和13.27；同时测定两个抗性生物型对丙草胺、苯噻酰草胺和莎稗磷3种细胞分裂抑制剂的交互抗性，结果显示，庆安03稻稗生物型对丁草胺和丙草胺产生了交互抗性；东京城镇02稻稗生物型对丁草胺、丙草胺和莎稗磷产生了交互抗性。【结论】黑龙江省部分地区稻稗对丁草胺产生了抗药性，且对丙草胺和莎稗磷产生了交互抗性。     

The USDA trypsin inhibitor study. I. Background,objectives, and procedural details

Short-term feeding studies have shown that raw soy flour and purified trypsin inhibitors (TI) cause pancreatic hypertrophy and hyperplasia in certain monogastric animals. Prolonged exposure to high levels of TI in raw soy ultimately leads to pancreatic nodular hyperplasia and acinar cell adenoma in rats exposed to low levels of pancreatic carcinogens. Such change has been observed even in the absence of any exposure to known carcinogens. These results emphasized the need for chronic (2 yr) feeding trials which would clearly reveal dose response relationships of alterations in pancreatic pathology to dietary TI and possible interactions with dietary protein and fat.Here we report on the objectives and designs of the first phase of the USDA TI Study, including composition of diets, preparation, and analyses of test substances. To provide the requisite TI and protein levels, raw and heated defatted soy flours, soy protein isolates, and lactic casein were used. The interrelationship of dietary level of TI (93–1270 mg/100 g diet) and that of protein (10%, 20%, and 30%) to pancreatic function and pathology will be reported in the following three papers. Both serial and chronic sacrifice regimes, respectively, were employed with 26 diets and 40 weaning male Wistar rats per dietary group.The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

Hydrolytic Enzyme Inhibitors and Necrotic Reactions in Potato Leaves Reduce Reproductive Success of Colorado Potato Beetle

In field and laboratory conditions the reproductive potential （survival at different stages of development） of the Colorado potato beetle has been measured, the dependence of the parameters of insects fertility on varietal features of the feed has been investigated, the food activity of the representatives of insects from four areas of the Southern Urals has been measured, the intensity and time of hypersensitivity reactions on potato leaves has been defined. In laboratory experiments, the level of activity of hydrolytic enzymes in insects and the level of activity of these enzymes inhibitors in the leaves of three potato varieties differing in their resistance to the Colorado potato beetle have been determined. The results show that the insects-representatives of different samples have different food activity in relation to different potato varieties. High mortality rates were revealed at feeding with leaves of potato of the Bashkir variety characterized by a high level of hydrolases inhibitors and relatively rapid development of necrotic reactions after the appearance of eggs laying on the leaves. We suppose that the neerogenetic barrier appearing in the form of necrosis is the major cause of the fetal mortality of insects. The level of the content of inhibitors inactivating larvae digestive enzymes affects the survival of insects at postembryonic stages. The speed of the necrosis emergence, the level of activity of digestive enzymes inhibitors in potato can be considered as criteria for the selection of breeding material for resistance to the Colorado potato beetle.     

Effects of aromatase inhibitors on reproduction in male three-spined sticklebacks, Gasterosteus aculeatus, exposed to long and short photoperiods

Three-spined stickleback Gasterosteus aculeatus, males were implanted with Silastic capsules filled with different aromatase inhibitors; 1,4,6-androstatriene-3,17-dione or the non-steroidal CGS16949 A, 4-(5,6,7,8-tetrahydrimidazol [1,5-a]pyridin-5-yl) benzonitrile monohydrochloride or empty capsules. The fish were then exposed to long or short photoperiod. Under the long photoperiod most fish in all treatments displayed a hypertrophied kidney (a secondary sexual character in sticklebacks) and completed, quiescent spermatogenesis, similar as in the natural spawning period. Under the short photoperiod the controls had unstimulated kidneys and an active spermatogenesis, whereas the males implanted with both aromatase inhibitors had stimulated kidneys, though not to the extent as in the long photoperiod, and completed, quiescent spermatogenesis. These findings suggest that aromatization is of importance for the inhibitory effects of short photoperiod on reproduction in the stickleback. This revised version was published online in July 2006 with corrections to the Cover Date.