Phenotypic and functional analysis of bovine peripheral blood dendritic cells before parturition by a novel purification method

Dendritic cells (DCs) are specialized antigen presenting cells specializing in antigen uptake and processing, and play an important role in the innate and adaptive immune response. A subset of bovine peripheral blood DCs was identified as CD172a⁺/CD11c⁺/MHC (major histocompatibility complex) class II⁺ cells. Although DCs are identified at 0.1%–0.7% of peripheral blood mononuclear cells (PBMC), the phenotype and function of DCs remain poorly understood with regard to maintaining tolerance during the pregnancy. All cattle used in this study were 1 month before parturition. We have established a novel method for the purification of DCs from PBMC using magnetic‐activated cell sorting, and purified the CD172a⁺/CD11c⁺ DCs, with high expression of MHC class II and CD40, at 84.8% purity. There were individual differences in the expressions of CD205 and co‐stimulatory molecules CD80 and CD86 on DCs. There were positive correlations between expression of cytokine and co‐stimulatory molecules in DCs, and the DCs maintained their immune tolerance, evidenced by their low expressions of the co‐stimulatory molecules and cytokine production. These results suggest that before parturition a half of DCs may be immature and tend to maintain tolerance based on the low cytokine production, and the other DCs with high co‐stimulatory molecules may already have the ability of modulating the T‐cell linage.     

贵州省猪源大肠杆菌对四环素类药物的耐药性及耐药基因检测

为考察贵州省猪源大肠杆菌对四环素类抗菌药的耐药情况和耐药基因的流行情况,本试验采用微量肉汤稀释法测定783株分离于贵州省8个地区规模化养殖场的猪源大肠杆菌对6种四环素类药物的敏感性,并通过PCR方法检测其携带四环素耐药基因情况。结果显示,猪源大肠杆菌对土霉素、四环素、金霉素、多西环素、米诺环素和替加环素的耐药率分别为97.3%、97.6%、96.6%、89.3%、48.0%和34.2%;土霉素和四环素的耐药水平最高,其MIC₅₀分别为256 和128 μg/mL,而MIC₉₀均为512 μg/mL,四环素的耐药倍数高于土霉素;米诺环素和替加环素的耐药水平最低,其MIC₉₀分别为32和4 μg/mL,耐药倍数相同;耐药基因tetA、tetB、tetC、tetD和tetM的检出率分别为92.60%、41.50%、58.75%、58.62%和70.10%;耐药菌株中主要以tetA基因为主,且大多数以携带复合基因的形式存在;大肠杆菌对土霉素、四环素、金霉素、多西环素和米诺环素的耐药性分别与耐药基因tetB和tetM呈极显著相关（P<0.01）,tetD基因分别与对米诺环素和替加环素的耐药性呈极显著相关（P<0.01）。贵州省猪源大肠杆菌对四环素类药物的耐药情况十分普遍,尤其是四环素和土霉素,金霉素和强力霉素有高度耐药的趋势;外排泵是四环素类药物主要的耐药机制;在兽医临床上越来越严重的耐药情况与耐药基因的广泛存在有很大关系。     

籼型水稻杂交种子真实性和纯度检验方法的研究──暗培养幼苗紫色性状有或无的实验

以水稻“三系”杂交种和保持系或不育系种子为材料，进行幼苗紫色性状外显差异性试验，筛选出：２５℃ＮＣ３０３型电热恒温箱内暗培养＋均匀摆种和适宜水分＋适宜光因子效应＋开叉期芽苗或不完全叶身的紫色性状为幼苗培养组合。获得杂交种子真实性和纯度检验方法，即暗培养幼苗紫色性状有或无鉴定。作者初步认为：暗培养幼苗紫色性状外显可能是“光因子效应”的结果；紫色性状外显有或无是由于纯合基因型与杂合基因型存在不同基因数目的剂量效应差异，从而表现外显时间差异的结果。     

Phänotyp und Futterqualitat einschliefilich Konservierungseigenschaften bei Grasern

Phenotype and forage value, including conservation properties, of grasses The phenotype of grasses can be influenced by the date of harvest as well as by breeding programs. In contrast to dicotyledons, the stems of grasses are younger than the leaves, although the grass leaves are usually considered to have a higher nutritional value than the stems. In a field experiment, Lolium multiflorum Lam. ssp. gaudini (Parl.) Schinz et Kell. was grown as a model-plant in order to study effects of ploidy-level, N-fertilization, stage of development, and growth time on the main aspects of nutritional value and conservation properties in relation to the phenotype. As regards the nutritional value, the interactions of ploidy × plant organ (=stem or leaf) and of ploidy × N-input were not significant. Hence, the results for leaf and stem can be generahzed. Until the emergence of the inflorescence, EC 49, the stem showed a significant higher net energy content than the leaf; at later stages of development this relationship changed. The evaluation of the net energy content of leaf and stem was significantly influenced by the method of estimation. In vitro methods with rumen liquor may show the best approximation to the real value. The crude protein/energy ratio of the stem as compared to the leaf better meets the nutritional requirements of ruminants; on the other hand the leaf was more valuable than the stem in relation to the nitrate content, especially when the whole plant showed an increased nitrate level. The general relationship between the mineral content and the phenotype was not evident. The investigation indicated significant differences between stem and leaf in relation to their conservation properties. The leaf showed more favourable drying properties than the stem but ensilability was better for the stem than for the leaf. As a result of this investigation it is assumed that, in the past, the nutritional value of young stem has been underestimated whereas the value of the leaf has been overemphasized. This may also be due to the criteria and determination methods of the nutritional value.     

不同组合CoBFA对雏鸡部分血液指标的影响

选用１日龄尼克红蛋公雏８０５只，随机分成７个组，Ⅰ－Ⅶ组为试验组，在饲料中分别添加以不同剂量的Ｚn、Se、Vc、VE、BFA(生化黄腐酸）配合面民的CoBFA，第Ⅶ组为对照。分别计数红细胞数、白细胞总数、白细胞分类数，测定血红蛋白含量，比较各组血液指标变化情况，分析各因素与雏鸡血液指标相关性，遴选最适组合。结果表明，红细胞与Ｖc、BFA显著相关（Ｐ＜０．０５）；淋巴细胞Ｖc极显著相关（Ｐ＜０．０１），与ＶＥ、ＢＦＡ显著相关（Ｐ＜０．０５）；血红蛋白含量Ｚn、Ｓe呈 正相关；白细胞总数与ＢＦＡ、Ｖc、VE呈较强正相关。     

三角城藏羊红细胞钾型的研究

采用火焰光度测定法对青海省三角城种羊场１０１只藏羊的红细胞钾型进行了研究，结果发现高钾型羊８０只（７９．２１％），低钾型羊２１只（２０．７９％），Ｋ￣ｂ和Ｋ￣Ｌ等位基因频率分别为０．８９００和０．１１００，同时还讨论了藏羊红细胞钾型与血红蛋白型的关系。     

A gene expression estimator of intramuscular fat percentage for use in both cattle and sheep

Background

The expression of genes encoding proteins involved in triacyglyceride and fatty acid synthesis and storage in cattle muscle are correlated with intramuscular fat (IMF)%. Are the same genes also correlated with IMF% in sheep muscle, and can the same set of genes be used to estimate IMF% in both species?

Results

The correlation between gene expression (microarray) and IMF% in the longissimus muscle (LM) of twenty sheep was calculated. An integrated analysis of this dataset with an equivalent cattle correlation dataset and a cattle differential expression dataset was undertaken. A total of 30 genes were identified to be strongly correlated with IMF% in both cattle and sheep. The overlap of genes was highly significant, 8 of the 13 genes in the TAG gene set and 8 of the 13 genes in the FA gene set were in the top 100 and 500 genes respectively most correlated with IMF% in sheep, P-value = 0. Of the 30 genes, CIDEA, THRSP, ACSM1, DGAT2 and FABP4 had the highest average rank in both species. Using the data from two small groups of Brahman cattle (control and Hormone growth promotant-treated [known to decrease IMF% in muscle]) and 22 animals in total, the utility of a direct measure and different estimators of IMF% (ultrasound and gene expression) to differentiate between the two groups were examined. Directly measured IMF% and IMF% estimated from ultrasound scanning could not discriminate between the two groups. However, using gene expression to estimate IMF% discriminated between the two groups. Increasing the number of genes used to estimate IMF% from one to five significantly increased the discrimination power; but increasing the number of genes to 15 resulted in little further improvement.

Conclusion

We have demonstrated the utility of a comparative approach to identify robust estimators of IMF% in the LM in cattle and sheep. We have also demonstrated a number of approaches (potentially applicable to much smaller groups of animals than conventional methods) to using gene expression to rank animals for IMF% within a single farm/treatment, or to estimate differences in IMF% between two farms/treatments.