青海省利用马铃薯抗晚疫病品种问题的商榷

青海省是我国马铃薯的重要产区之一。晚疫病在本省容易发病的地区最近十年中流行了五次(1954、1955、1958、1959、1961年)平均每两年流行一次,一般减产在20％左右。但也有经常不流行的地区可以被利用为免疫品种繁育的基地。 1.晚疫病在青海不同地区的流行规律: 晚疫病的流行与否,完全决定于当年的气候条件。由于青海省地形复杂,各地的发病条件也不一致。根据影响晚疫病流行的两大主要气候因素——相对湿度和温度,大致可以分为三类地区: 第一类地区为温度能经常满足病害流行要求。如东部农业区的川水和部分浅山地区(海拔     

Development of multiplex polymerase chain reaction assays for detecting enterotoxigenic Escherichia coli and their application to field isolates from piglets with diarrhea.

Fimbriae and enterotoxins are major virulence factors associated with enterotoxigenic Escherichia coli (ETEC). In this study, 3 sets of multiplex polymerase chain reaction (mPCR) assays targeting fimbriae, enterotoxins, and other adherence factors were developed for detecting ETEC. A total number of 188 E. coli field isolates were examined, and percentages of E. coli strains carrying each virulence factors were as follows: F4 (7.45%), F5 (29.79%), F6 (6.38%), F18 (15.43%), F41 (3.72%), STa (10.11%), STb (20.74%), LT (9.57%), Stx2e (2.13%), EAST1 (42.02%), F1 (67.55%), AIDA-I (2.66%), and pAA (7.45%). Of the 188 E. coli field isolates examined, 25.53% were found to be pathogenic ETEC, having both fimbriae and enterotoxins. However, the ratio increased to 44.68% when the presence of other adhesins was considered as criteria for virulence. Among the adherence factors, F1 was found to be the most prevalent. AIDA-I and pAA were also found with similar ratio as compared with other virulence factors. In addition, virulence patterns carrying these alternate adhesive genes with enterotoxins were detected with significant ratio. Therefore, it is desirable that alternate adhesins be considered as markers for diagnosis of ETEC.     

Effect of dietary energy on digestibilities,rumen fermentation,urinary purine derivatives and serum metabolites in Tibetan and small‐tailed Han sheep

Tibetan sheep are indigenous to the Qinghai–Tibetan Plateau, graze the grassland all year round without supplementation and are well‐adapted to the harsh conditions. Small‐tailed Han sheep were introduced to the plateau and are raised mainly in feedlots. Based on their different backgrounds, we hypothesized that the ability to cope with poor diets would be better in Tibetan than in Han sheep. To test our prediction, we examined the effect of dietary energy on apparent digestibilities, rumen fermentation, urinary purine derivatives and serum metabolites by using a 4 × 4 Latin square design in each sheep breed. Four diets were formulated to be low in crude protein (~7%) but to differ in metabolizable energy concentration. Average daily gain was greater in Tibetan than in Han sheep (p < 0.01) and increased linearly with an increase in energy intake (p < 0.001). The digestibilities of dry matter, organic matter, gross energy, and neutral and acid detergent fibres were greater in Tibetan than in Han sheep (p < 0.05). Ruminal pH was lower (p < 0.05), while volatile fatty acids (VFAs), urea‐N, ammonia‐N and soluble protein‐N concentrations were higher (p < 0.05) in Tibetan than in Han sheep. As a molar proportion of total VFA, acetate decreased (p < 0.001) with an increase in dietary energy whereas propionate and butyrate increased (p < 0.05). Urinary purine derivative excretion was greater in Tibetan than in Han sheep (p < 0.01), as was microbial nitrogen production; both parameters increased with dietary energy (p < 0.01). Serum concentrations of glucose, insulin and insulin‐like growth factor‐1 increased (p < 0.05) as energy level increased, while non‐esterified fatty acids and growth hormone decreased (p < 0.05). It was concluded that Tibetan sheep were better able to cope with low‐protein, low‐energy diets and, consequently, our prediction was supported.     

猪瘟病毒Erns蛋白在杆状病毒系统中的表达及纯化

采用杆状病毒表达系统表达并纯化猪瘟病毒E^rns蛋白,并对其反应原性进行鉴定。将猪瘟病毒的E^rns 基因克隆至pFastbac-HT-A 载体上,构建了pFA-E^rns重组质粒;经转座、转染后构建重组杆状病毒rBac-E^rns;通过优化接毒时间和接毒量等参数,最终确定表达条件。将表达产物采用亲和层析法纯化后,采用Western Blotting 鉴定E^rns 蛋白的反应性,并采用间接ELISA 方法对其应用进行了初步探索。结果显示,获得了重组杆状病毒rBac-E^rns,经Western Blotting 和间接免疫荧光(IFA)鉴定,该重组病毒能够与猪瘟阳性血清和E^rns 单抗发生特异性反应。纯化后的E^rns 蛋白纯度较好,浓度为0. 2 mg/ mL,经Western Blotting 方法鉴定证明,纯化后的蛋白与E^rns单抗和猪瘟阳性血清能够发生特异性反应;初步建立了间接ELISA 方法检测猪瘟抗体,证明表达的蛋白可以区分猪瘟阳性血清和阴性血清。表明本研究利用杆状病毒表达系统成功表达并纯化了猪瘟病毒E^rns蛋白,纯化后的E^rns蛋白具有良好的反应性,可以作为开发鉴别诊断试剂的备选蛋白以及用于E^rns 蛋白的结构和生物学功能研究。     

The effect of dietary high energy density and carbohydrate energy ratio on digestive enzymes activity,nutrient digestibility,amino acid utilization and intestinal morphology of weaned piglets

This study evaluated the effect of high or low digestible energy ratio of carbohydrate in a high or normal dietary energy density on performance, amino acid utilization and intestinal functions of weaned piglets. A total of 32 healthy weaners (9.60 ± 0.13 kg) were allocated to two dietary energy densities (3,400 and 3,800 kcal/kg) and two digestible energy ratio of carbohydrate to fat (9:1 and 3:1) in a 2 × 2 factorial arrangement. There were eight piglets per treatment. The feed intake of piglets was significantly increased by dietary high carbohydrate ratio (9:1) (p < 0.01); however, this did not result in improved body weight gain (p > 0.05). The piglets fed high carbohydrate energy ratio had a reduced villus height/crypt depth (VH/CD) ratio in the duodenum (p < 0.05), and dietary high energy density further decreased the VH/CD ratio in the ileum (p < 0.01). In the duodenum, the lymphocyte count was increased by dietary high energy density (p < 0.05), while dietary energy density and carbohydrate energy ratio interacted to increase lymphocyte count in the ileum (p < 0.05). The serum cholesterol, triglyceride and low‐density lipoprotein were not significantly affected (p > 0.05), but dietary energy density interacted with dietary energy ratio to increase high‐density lipoprotein concentration (p < 0.05) in piglets fed reduced carbohydrate energy ratio. Dietary high energy density reduced energy digestibility (p < 0.05), whereas high carbohydrate energy ratio increased crude protein digestibility in the piglets (p < 0.05). The intestinal sucrase, lactase activities and serum concentrations of histidine, leucine, lysine, methionine, phenylalanine, alanine, glycine, tyrosine and citrulline were higher in the piglets fed dietary increased carbohydrate energy ratio. Oxidative stress markers and volatile fatty acids concentrations were altered by the dietary treatments. It was concluded that dietary high energy density could be detrimental to piglets intestinal functions and that increased carbohydrate energy ratio could affect amino acid utilization and body weight gain in weaner pigs.     

番茄新品种东农712的选育

东农712是以01HN43为母本,以01HN37为父本配制而成的中晚熟番茄一代杂种,生育期117 d（天）左右,高抗番茄花叶病毒（ToMV）、叶霉病、枯萎病和黄萎病。果实高圆形,单果质量240~300 g,果实粉红色,果面光滑圆整,成熟果硬度0.49 kg·cm^-2,耐贮运;丰产性好,每667 m²产量6 500~8 500 kg,适合全国各地保护地和露地栽培。     

Skeletal unit construction of rat mandible based on the masticatory muscle anatomy and double microcomputed tomography

This study aimed to divide the mandible into skeletal units based on three‐dimensional (3D) muscular anatomy with microcomputed tomography (micro‐CT) of Sprague–Dawley rat. Five normal rats were micro‐CT scanned at 12 weeks of age before and after contrast enhancements for the masticatory muscles. Three‐dimensional reconstruction of the mandible was performed from the initial micro‐CT images, followed by segmentation of the masticatory muscles using the second enhanced micro‐CT data. Bone and muscle models were superimposed based on the teeth and bony structures to evaluate muscular orientation and attachment. The mandible was divided into skeletal units using the bony structures and muscle attachments. The mandibular foramen and mental foramen were adopted as the reference points based on their anatomical and developmental significance. The skeletal units consisted of the condylar, coronoid, angular, body and symphyseal units. Further evaluation of these units in relation to development, growth, and other biology and medicine will be helpful in elucidating their biological identities.     

苜蓿素对脂多糖诱导下奶牛乳腺上皮细胞炎症和乳蛋白合成相关基因表达的影响

为分析苜蓿素对脂多糖诱导下体外培养奶牛乳腺上皮细胞抗炎和乳蛋白合成相关基因表达的影响,本研究将体外培养的奶牛乳腺上皮细胞分成4组,即基础培养基(对照)和基础培养基中分别加入1μg·m L-1LPS(L)、1μg·m L-1LPS+10μg·m L-1苜蓿素(L+T)和10μg·m L-1苜蓿素(T)。结果显示,1)与对照组相比,L组奶牛乳腺上皮细胞的活性显著下降(P0.05),而T组则显著升高(P0.01)。2)L+T组细胞的超氧化物歧化酶(SOD)活性显著高于L组(P0.01),而一氧化氮(NO)、丙二醛(MDA)含量则显著低于L组(P0.01)。3)LPS能够显著升高细胞的白细胞介素1β(IL-1β)、IL-6、肿瘤坏死因子α(TNF-α)、Toll样受体2(TLR2)、TLR4和髓样分化因子88(My D88)表达水平(P0.01),而添加苜蓿素能够显著降低IL-1β、TNF-α、TLR2和TLR4的表达水平(P0.01)。4)与对照组相比,T组细胞的酪氨酸激酶2(JAK2)、信号转导子和转录激活子5(STAT5)、雷帕霉素靶蛋白(m TOR)、真核细胞始动因子4E结合蛋白1(4EBP1)和核糖体S6蛋白激酶1(S6K1)表达量显著升高(P0.01),而碱性氨基酸转运载体1(CAT1)表达量显著降低(P0.01)。LPS能够显著降低细胞的CAT1、L型氨基酸转运载体1(LAT1)、STAT5、m TOR和4EBP1表达水平(P0.01或P0.05),而添加苜蓿素能够显著升高STAT5表达水平(P0.01)。结果表明,乳腺细胞在LPS刺激下,导致细胞内炎症因子基因表达升高和抑制乳蛋白合成相关基因的表达,而添加苜蓿素能够抑制乳腺细胞内炎症因子基因表达,但对乳蛋白合成的相关基因表达作用不明显;无LPS刺激下,添加苜蓿素能够提高乳腺细胞活性和促进乳蛋白合成相关基因的表达。     

苜蓿黄酮对脂多糖诱导下奶牛乳腺上皮细胞凋亡的影响

研究苜蓿黄酮对脂多糖(LPS)诱导下奶牛乳腺上皮细胞凋亡的影响。将奶牛乳腺上皮细胞分成4个组,即基础培养基、基础培养基中加入1 μg·mL^-1的LPS、基础培养基中加入1 μg·mL^-1的LPS和75 μg·mL^-1苜蓿黄酮、基础培养基中加入75 μg·mL^-1苜蓿黄酮。细胞在37 ℃, 5% CO₂的培养箱中培养。结果表明:1)LPS刺激12 h后奶牛乳腺上皮细胞活性下降,而添加苜蓿黄酮能够极显著抑制LPS诱导下细胞活性的下降(P<0.01)。2)在LPS刺激下,细胞内的活性氧(ROS)浓度升高,而添加苜蓿黄酮能够显著降低其浓度(P<0.05)。3)LPS显著上调细胞的IL-1β、IL-6、TNF-α、TLR2、TLR4和MyD88表达(P<0.01),而苜蓿黄酮能够显著下调细胞的IL-1β、IL-6、TNF-α和TLR2表达(P<0.01或P<0.05)。4)在LPS刺激下,p53、Caspase3、p38和P-p38蛋白的表达显著升高(P<0.01或P<0.05),而添加苜蓿黄酮能够显著降低p53和p38蛋白的表达(P<0.05)。在LPS诱导下,苜蓿黄酮能够通过降低ROS浓度,抑制细胞凋亡,提高细胞活性;可能通过抑制TLR2/MyD88信号通路来降低细胞炎症因子的表达,从而保护细胞免受炎性损伤。