放线菌Act1对连作西瓜枯萎病的防治效果

为了探索放线菌制剂Act1对连作西瓜枯萎病的防治效果及其对西瓜根际微生物含量的影响,采用大棚小区田间试验,以不接种放线菌制剂Act1为对照,以播种期接种和定植期接种为处理,研究不同处理对西瓜生长、枯萎病发生及其根域微生态的影响。结果表明:接种放线菌制剂的处理均能显著降低连作西瓜枯萎病的发生率,其中育苗期接种防效最显著,达到52.17%;育苗期接种放线菌制剂Act1显著促进了植株的生长;并增加了西瓜根区细菌和放线菌的数量,降低了真菌的数量且A/F、A/B、B/F与对照相比分别增加了1.38～5.5、1.53～5.25、1.29～1.75倍。接种放线菌制剂Act1的处理均能显著防治连作西瓜枯萎病的发生并改善根际微生物的组成。     

不同季节牧草钙磷含量对放牧绵羊血清骨钙素的影响

研究了不同季节牧草钙磷含量对放牧绵羊血清骨钙素、碱性磷酸酶、血清钙、无机磷、血清钙磷比和血清钙磷乘积的影响。结果表明:这些血清指标随季节变化明显,血清骨钙素夏季含量为(2.009±0.888)ng/mL,极显著的低于冬春季(3.974±1.281)ng/mL和秋季(3.279±1.365)ng/mL的含量(P<0.05)。从相关分析中看出,骨钙素与AKP、血钙、无机磷、血钙/磷和血钙磷乘积呈正相关,相关系数分别为0.047、0.546、0.035、0.394、0.489。与牧草钙、磷和钙磷比呈负相关,尤其与牧草钙的相关系数达-0.657(P<0.01)。利用逐步回归的方法得出的骨钙素与牧草钙、血清钙的多元回归方程为:骨钙素=1.813-2.358牧草钙+0.945血清钙(P<0.05)。认为血清骨钙素可以作为反映放牧绵羊钙磷盈缺状况的灵敏指标。     

Mechanical wounding induces the formation of extensive coated membranes in giant algal cells

Mechanically wounding giant cells of Boergesenia forbesii induces the formation of bristle-coated, plasma-membrane invaginations (coated pits) and coated vesicles, easily providing a plentiful source of coated membranes in a clean cellular system unencumbered by other tissues. Contractions evoked by wounding partition the cytoplasm into hundreds of spherical protoplasts with approximately 40 percent less total plasma-membrane surface area than the original cell. Ferritin labeling and the appearance of numerous large coated pits and vesicles at the peak period of contraction indicate that these organelles play a role in extensive endocytosis of the plasma membrane.     

Functional and Rheological Properties of Amaranth Albumins Extracted From Two Mexican Varieties

The functional and rheological properties of amaranth albumins isolates extracted from two new Mexican varieties were determined. Functional properties tested were protein solubility, foaming, water and oil absorption capacities, emulsifying activity, and emulsion stability. The maximum solubility values for both amaranth albumins were found above pH 6 and values were compared to the solubility of egg albumins. Albumins from amaranth showed excellent foaming capacity and foaming stability at pH 5, suggesting that this protein could be used as whipping agents as egg albumins, also the water and oil absorption capacities reached their maximum values at acidic pH, suggesting that amaranth albumins could be appropriate in preparation of acidic foods. The rheological test based on farinograms and alveograms showed that wheat flour supplemented with 1% amaranth albumins improves the dough properties due to higher mixing stability and the bread had better crumb characteristics. In addition of the known high nutritional values of amaranth albumins, our results indicate the high potential for use of these proteins as an ingredient in food preparations.     

Oestrus detection techniques and insemination strategies in Bos indicus heifers synchronised with norgestomet-oestradiol

SUMMARY Oestrus was synchronised in 57 Bos indicus heifers using norgestometoestradiol and pregnant mare serum gonadotrophin. Oestrus was detected by observations made at six-hourly intervals, using oestrogen-treated and chin-ball harnessed steers, heatmount detectors, tail-paint and visual observation. Heifers were inseminated once at either a fixed time of 49.2 ± 0.4 h (mean ± SE; n = 29) after implant removal or 12.6 ± 1.5 h (n = 28) after oestrus was detected. The mean (± SE) time to the onset of oestrus was 47.1 ± 1.9 h, while 90% of heifers recorded in oestrus were detected within 66 h of implant removal. Heatmount detectors were significantly more efficient at detecting oestrus than chin-ball harnessed steers, tail paint or visual observation (P < 0.001). A higher pregnancy rate was obtained in heifers inseminated after oestrus detection compared with heifers inseminated at a fixed-time (57.1 vs 34.5%; P = 0.043) and a higher pregnancy rate was obtained in heifers classified as easy to inseminate compared with heifers classified as difficult to inseminate (57.8 vs 0%, P < 0.001). We conclude that heatmount detectors are an efficient means of detecting oestrus in synchronised B indicus heifers and that pregnancy rates can be increased when insemination follows oestrus detection compared with a fixed-time insemination regimen.