硫酸黄连素与硫酸粘菌素的体外联合抑菌研究

为了考察硫酸黄连素与硫酸粘菌素的联合抑菌作用,对硫酸黄连素和硫酸粘菌素单一和联合应用分别对仔猪大肠杆菌(C83901),猪多杀性巴氏杆菌(C44-1),鸡白痢沙门氏菌(C79-6),禽多杀性巴氏杆菌(C48-1)进行药物敏感性试验;结果:硫酸黄连素对以上4株菌的M IC值分别为:32,128,64,128μg/mL;硫酸粘菌素对以上4株菌的M IC值分别为:64,128,128,256μg/mL;联合应用对上述4株菌的FIC指数分别为:0.375,0.375,0.25,0.5。结果显示上述4株菌对硫酸黄连素与硫酸粘菌素联用的FIC指数均小于0.5,表现为协同作用。二者最佳比例为1∶2~1∶4,这为复方制剂的开发提供了一定的理论依据。     

影响棉籽饼有效赖氨酸含量因素的试验研究

本试验模拟螺旋压榨榨油工艺，测定不同蒸炒或加热条件对棉籽饼中自由棉酚（ＦＧ）、还原糖（ＲＳ）、有效赖氨酸（Ａ－Ｌｙｓ）含量的影响。对蒸炒前喷洒硫酸亚铁的作用也做了初步探讨。研究发现，加热强度、棉酚结合、还原糖含量与有效赖氨酸含量之间的相关系数分别为－０．９７６５（Ｐ＜０．０１）、－０．９５１５（Ｐ＜０．０１）、０．４３９５（Ｐ＞０．０５）；蒸炒前添加ＦｅＳＯ４，按Ｆｅ∶ＦＧ摩尔比４．５∶１和９∶１时均极显著地（Ｐ＜０．０１）提高Ａ－Ｌｙｓ含量，两剂量组间无差异（Ｐ＞０．０５）；按４．５∶１添加ＦｅＳＯ４可提高Ａ－Ｌｙｓ７．６０％～３７．７７％，同时表明，ＦＧ含量显著降低。     

Inhibition by aluminum of mycelial growth and of sporangial production and germination inPhytophthora infestans

Mycelial growth on clarified V8 agar of the potato late blight pathogenPhytophthora infestans was inhibited when either aluminum chloride (AlCl₃, 6 H₂O) or aluminum sulfate (Al₂(SO₄)₃, 18 H₂O) was added to the culture medium at concentrations of 2.5–100 mg.l^–1 Al³⁺. Toxicity of Al³⁺ varied among the fiveP. infestans isolates tested, but toxicity of sulfate and chloride salts was similar for a given isolate. Overall sporangial production was affected in all five isolates by both Al³⁺ forms. Al³⁺ also decreased sporangial germination at concentrations equal to or greater than 10 mg.l^–1 in two isolates. These data support the hypothesis of aluminum toxicity as a major factor in soil suppressiveness toP. infestans.     

紫外分光光度法测定硫酸链霉素的含量

采用紫外分光光度法测定硫酸链霉素的含量,检测波长323 nm.硫酸链霉素在12～48 mg/L的浓度范围内,其紫外吸收值与浓度呈线性关系,回归方程为A=0.012 1 C 0.000 5,r=0.999 9;平均回收率为99.82%,RSD为0.62%.     

靶向硫酸庆大霉素结合物的制备和免疫原性研究

将硫酸庆大霉素与大肠埃希菌血清抗体用化学修饰剂进行偶联,再经适当的化学方法处理,按照制剂学原理制备成靶向硫酸庆大霉素,经电镜检测,可以清楚的看到抗体球蛋白上附着的硫酸庆大霉素药物颗粒。应用间接ELISA法检测靶向硫酸庆大霉素结合物的免疫原性。结果表明,结合物存在微弱的免疫原性,但与大肠埃希菌血清抗体相比,免疫原性已经大为减弱,说明靶向硫酸庆大霉素复合物中,化学修饰剂不仅扮演偶联物的角色,还减弱了结合物中大肠埃希菌血清抗体的免疫原性,对靶向硫酸庆大霉素结合物的药动学和药效学几乎无影响。     

Application of gypsum and lime to increase cation adsorption of a Geric Ferralsol in the Brazilian Amazon region

A Brazil-nut plantation 140 km east of Manaus was the site of a 3-month field trial, in which a by-product gypsum and a lime were compared. The soil properties in the plantation, 23 years after slash-and-burn, are not basically different from the remaining primary forest. The comparison is impeded by a distinct spatial variability of the soil nutrient content within the plantation. A linkage between Effective Cation Exchange Capacity (ECEC) and sulfate content of the soil is presumed. Gypsum-application increases the exchangeable Ca considerably, which is not an effect of Al-exchange, but of newly created adsorption sites. The potential of gypsum to increase the ECEC corresponds on a 1:1 basis with the potential for sulfate adsorption in the soil. Mg and nitrate are strongly leached after gypsum application. The applied, extremely fine ground lime has almost no effects below 5—10 cm depth. Ca, Mg and, to a lesser extent, K exhibit a much enhanced adsorption when applied as sulfate instead of chloride. All three cations are preferentially adsorbed in the subsoil, where the ECEC is only half the value of the upper soil. For fertilization concepts of those soils, the subsoil deserves much greater attention. The infiltration pattern of an organic dye gives evidence of a strong influence of bypass water flow through macropores in the soil.     

硫酸铝对苏打盐碱土化学性质及水稻产量的影响

苏打盐碱土中添加硫酸铝的质量分数为0%~0.6%时,土壤平衡溶液的pH值由10.2迅速降低至8.2,硫酸铝的质量分数为0.6%~2.0%时,pH值仅降低0.55,呈缓慢下降趋势。盆栽试验表明,随硫酸铝用量的增加,土壤中CO32-和HCO3-的含量降低,硫酸铝添加量为0%~0.4%时,SO42-含量增加,添加量为0.5%~0.6%时下降,土壤盐分组成:苏打型→苏打-硫酸盐型→硫酸盐型。土壤交换性Na 含量和碱化度与硫酸铝用量呈显著负相关(r=0.995 8,r=0.995 4)。水稻有效分蘖数、千粒重随硫酸铝用量的增加而提高,水稻当年产量最高可达6 000 kg/hm2,与对照相比,增产41.67%~66.67%。     

解淀粉芽孢杆菌ASR-12抗菌蛋白的分离纯化 及其编码基因克隆

为了从菌株ASR-12发酵液中分离纯化获得抗菌蛋白。将菌株ASR-12发酵液经硫酸铵沉淀、透析除盐后获得粗蛋白,粗蛋白进行热处理和Q Sepharose Fast Flow柱层析,纯化后的蛋白进一步进行LC-MS鉴定,并克隆其编码基因进行测序。粗蛋白经热处理和柱层析后得到5个吸收峰,活性检测结果显示峰Ⅳ具有较高抑菌活性,经SDS-PAGE检测显示为单一条带,分子量约为50k Da。LC-MS鉴定结果显示抗菌蛋白与M42家族肽酶同源性最高,覆盖度达到80%;并能从菌株ASR-12基因组中克隆到M42家族肽酶编码基因,测序结果经BLAST比对与解淀粉芽孢杆菌B9601-Y2的M42家族肽酶编码基因同源性达100%。菌株ASR-12产生的抗菌蛋白中,M42家族肽酶为主要活性成分。