金黄色葡萄球菌α-溶血素的研究进展

目的α-溶血素在金黄色葡萄球菌(金葡菌)肺炎的感染过程中起着非常重要的作用,可作为治疗金葡菌肺炎的新靶标。因此,研究百里香酚对金葡菌α-溶血素表达的影响具有重要意义。方法测定最小抑菌质量浓度(MIC)和生长曲线并进行了溶血试验、蛋白免疫印迹分析、荧光定量PCR以及细胞毒性试验。结果百里香酚对金葡菌USA300的MIC为256 μg/mL,亚抑菌质量浓度的百里香酚(32 μg/mL)可下调金葡菌hla和RNAIII的转录水平,降低α-溶血素的表达,对溶血素介导的肺癌上皮细胞A549损伤具有保护作用。结论百里香酚具有成为新型抗金葡菌感染药物的潜力。     

猪外周血单个核细胞增殖反应影响条件的探讨

应用 Ｌ１６ （４５） 正交试验, 对影响猪 Ｐ Ｂ Ｍ Ｃ 增殖反应的几个因素, 包括培养时间、 Ｐ Ｈ Ａ 浓度、细胞浓度等三个因素四个水平进行了比较和探索。试验表明几个因素对 Ｐ Ｂ Ｍ Ｃ 的增殖反应均有显著的影响（ Ｐ＜ ００５） , Ｐ Ｂ Ｍ Ｃ 增殖反应的 Ｍ Ｔ Ｔ 比色法的最佳反应条件组合为 Ｐ Ｂ Ｍ Ｃ 浓度为１ ×１０６／ｍｌ, 植物血凝素 Ｐ Ｈ Ａ 的浓度为１２５μｇ／ ｍｌ, 细胞培养时间为２４ 小时; 影响增殖反应的先后顺序为 Ｐ Ｂ Ｍ Ｃ 浓度、 Ｐ Ｈ Ａｐ 浓度及细胞培养时间。同时确定了最有利于 Ｐ Ｂ Ｍ Ｃ 增殖的犊牛血清浓度为１０ ％ 。     

不同贮藏条件鸡蛋的脂类过氧化作用

本文以ＴＢＡ光度法分析了不同贮藏条件下鸡蛋脂类的过氧化作用,并分析了温度、氧对过氧化作用的影响。结果表明,在贮藏条件下,鸡蛋蛋黄中伴有明显的脂类过氧化过程。脂类过氧化物（ＬＰＯ）的水平随贮藏时间的延长而不断增加（Ｐ＜０．０１）,但蛋清中的ＬＰＯ在贮藏过程中没有明显的变化。低温和缺氧可明显抑制鸡蛋脂类的过氧化作用（Ｐ＜０．０１）。     

Three novel single-nucleotide polymorphisms of MBL1 gene in Chinese native cattle and their associations with milk performance traits

Mannan-binding lectin (MBL), a pattern recognizing serum protein, participates in the innate immune system of mammals as an opsonin. In humans, single-nucleotide polymorphisms (SNPs) in MBL2 gene were found to cause various innate immune dysfunctions. In the present study, we discovered three single-nucleotide polymorphisms of the MBL1 gene in Chinese native cattle and analyzed their associations with milk traits. By screening the genetic variation of MBL1 in 1053 individuals of three Chinese native cattle breeds including China Holstein, Luxi Yellow and Bohai Black using created restriction site–polymerase chain reaction (CRS–PCR), PCR–restriction fragment length polymorphism (PCR–RFLP) and DNA sequencing techniques, three new SNPs, g.855G>A, g.2651G>A and g.2686T>C, were found to have allele frequencies of 0–12.65%, 24.07–42.39% and 56.95–73.68%, respectively. While SNP g.855G>A is located within intron ?, the other two SNPs reside in the exon II region with one mutation being non-synonymous (GTT (Val) > ATT (Ile)) and the other synonymous (GCT (Ala) > GCC (Ala)). Among the 596 Chinese Holstein cattle with at least 3 lactation Dairy Herd Improvement (DHI) records, eight different haplotypes and 19 genotype combinations were detected. Statistical analyses revealed no correlation between either g.855G>A or g.2686T>C and somatic cell score (SCS), however significant association was found between g.2651G>A and SCS, suggesting a possible role of this SNP in the host response against mastitis. Our data also suggested that the combined genotypes of GGC/AAC with the lowest SCS, AAT/AAT with the highest protein content and AGC/AGC with the highest 305-d milk yield were favorable combinations for mastitis resistance and milk production traits. Therefore, GGC/AAC, AAT/AAT and AGC/AGC can be used as possible candidates for marker-assisted selection in the dairy cattle breeding program.     

狗牙根草坪冬季盖播黑麦草的可行性研究

用2种黑麦草在广州赛马会高尔夫球练习场的狗牙根草坪上进行了冬季盖播可行性试验。结果表明，冬季盖播黑麦草后，盖播处理区的狗牙根草坪同没有盖播的对照区草坪相比，绿期延长，同时其它坪用性状也明显提高，因而证明，在广州地区的狗牙根草坪上用黑麦草进行了加绿盖播是完全可行而必要的。同时试验结果表明，草坪型黑麦草盖播草坪的坪用性状远远好于牧草型黑麦草的盖播处理。此外，合理的施肥和播量等因素也将直接影响盖播草坪的冬季坪用性状以及夏枯时狗牙根草坪的恢复生长。播量以20g/m^2最为理想，可根据建植和管理水平酌情增减。生长前期以高施肥（90g/m^2）为宜，夏枯前后的过渡阶段，以低施肥（45g/m^2）为佳。     

预混料企业真的需要转型吗?

《饲料广角》杂志21期所刊登的胡文辉先生大作《预混料企业需要尽快转型》，文章固然精彩，然而，预混料企业真的需要转型吗？笔者认为．尚需商榷。     

中药“增免散”对免疫抑制鸡免疫功能的影响

将300只1日龄雏鸡随机分成正常对照组、中药“增免散”组、环磷酰胺组、环磷酰胺组 左旋咪唑组、环磷酰胺 “增免散”组,6日龄用鸡新城疫LaSota疫苗免疫点眼滴鼻,14、21、28、35日龄测定鸡血液ND抗体效价、免疫器官指数、细胞免疫功能、红细胞免疫粘附功能等,探索中药“增免散”的免疫增强机理。结果表明:中药“增免散”不但能显著提高Lasota活苗接种雏鸡的特异性HI抗体水平,延长其持续时间,能促进雏鸡免疫器官的生长发育,能显著增高雏鸡外周血T淋巴细胞ANAE阳性率,并对雏鸡红细胞免疫粘附功能具有显著促进作用,而且对环磷酰胺的免疫抑制有部分拮抗作用。     

mRNA差异显示技术及其在动物遗传育种中的应用

ｍＲＮＡ差异显示技术是近年来国外发展起来的攻克隆新基因的一种新方法,同时已广泛用于人类基因调控和克隆研究。本文论述了这一新技术的原理、发展现状和在动物遗传育种中的应用领域。     

Structural and metabolic integrity of sheep external intercostal muscle during extended culture

The objectives of this study were to examine the structural and metabolic integrity of isolated sheep external intercostal muscle bundles following variable lengths of preincubation (0 to 192 h). Samples of intact external intercostal muscle (10 to 15 g), with tendons attached, were prepared from growing wethers and maintained at their resting lengths during preincubation for 0 to 192 h. Protein synthesis (PS), protein degradation (PD), acetate oxidation and ultrastructural integrity of muscle samples were examined at 0 to 192 h, 0 to 96 h, 0 to 48 h and 0 to 96 h following isolation, respectively. Additionally, the effects of variable fetal calf serum (FCS) concentrations (0 to 20%; w/v) on PS and PD and acetate oxidation were examined. Rate of PS increased as preincubation time increased to 192 h; however, most of this increase was due to the proliferation of fibroblasts on the surface of the muscle sample. Addition of cytosine arabinoside to the incubation media prevented the fibroblast-dependent increase in PS; however, it did not entirely prevent the preincubation time-dependent increase in PS. Rate of PD increased greatly upon preincubation. The nitrogen balance of incubated muscles was negative at all times examined. Acetate oxidation was maintained through 12 h of preincubation and thereafter declined. Relatively normal myofibrillar structure was maintained through 48 h of preincubation; however, loss of mitochondrial integrity and dissolution of Z-disks at 48 h and at 96 h of preincubation were evident. Isolated tissues were able to respond to FCS concentration in medium following 48 h of preincubation.     

獒本杂交犬繁育性能研究

通过对獒本杂交犬与当地土种犬发情时间、配种时间、产活仔数、幼犬初生重等的对比研究,发现獒本杂交犬发情时间集中在9~11月份,发情受胎率与母犬年龄及养殖条件有关,常规养殖下3~4岁獒本杂交母犬发情率为100%,2~4岁獒本杂交母犬受胎率达到100%。獒本杂交犬产仔力和哺乳性能等繁育性能指标明显高于本地土种犬,1~5岁龄杂交母犬的平均活产仔数显著高于当地土种犬(P(0.05);仔犬平均初生重显著高于当地土种犬(P(0.05);仔犬断奶平均个体体重显著高于当地土种犬(P(0.01);仔犬断奶平均窝重显著高于当地土种犬(P(0.05);幼犬断奶成活数比土种犬高14.3%。