Variations in parameters of liver function and plasma progesterone related to underfeeding and ketosis in a dairy herd

Twenty-eight Norwegian Red Cattle dairy cows were fed silage ad libitum and restricted amounts of concentrates. Blood samples were collected before morning feeding, once or twice weekly, from 2 weeks before to 12 weeks after calving. Parameters of liver function, carbohydrate status and fertility were recorded in order to assess their interrelationships. Eight cows were treated for clinical ketosis. Four of these had to be treated 2 or 3 times. Aspartate aminotransferase and bilirubin showed the highest within-animal coefficients of correlation with acetoacetate. Analysis of variance revealed a significant effect of carbohydrate status (indicated by plasma acetoacetate levels) on the levels of aspartate aminotransferase, glutamate dehydrogenase and sorbitol dehydrogenase, though only a small part of the total variation was explained by this factor. The estimated volume density of liver fat in the 4th week of lactation averaged 6.0 +/- 6.4% (+/- SD) ranging from 0.1-25.1%. Liver fat content at this stage of lactation was not significantly correlated with other indicators of liver function or carbohydrate status. Cows treated for clinical ketosis had significantly lower plasma progesterone values at the time of first ketosis treatment than untreated multiparous cows. The frequency of high progesterone values (greater than 3 ng/ml) being significantly lower in treated than in untreated cows during the period from 3-5 weeks post partum, though not at later stages. In conclusion, the results revealed a significant relationship between carbohydrate status and liver function, and also between clinical ketosis and luteal function.     

D-Dimer Improves the Prognostic Value of Combined Clinical and Laboratory Data in Equine Gastrointestinal Colic

The discriminating ability of 15 parameters alone or in combinations, including results from analysis of plasma endotoxin, the Nycomed plasma D-Dimer test and phospholipase A₂, were analyzed to predict morbidity and mortality in equine gastrointestinal colic. Endotoxaemia was a characteristic feature of the colic horses. The problem of adequately predicting non-survivors among colic horses required several parameters to be included in the logistic model: if the “classical parameters”, (heart rate, respiratory rate, PCV, anion gap) were included in the model, addition of plasma D-dimer, phospholipase A₂, and Cl^- significantly improved the predictive value of the logistic model. Increasing heart rate and D-dimer together with decreasing chloride was a risk factor for nonsurvival. The sensitivity of this three-parameter logistic model to predict nonsurvival was 78% and specificity 77%. The Nycomed D-Dimer test is recommended as a horse-site test to predict disseminated intravascular coagulation and nonsurvival in equine colic.     

The potential use of plasma glutamate dehydrogenase activity for the evaluation of hepatic disease in the cockatiel (Nymphicus hollandicus)

A reference interval for plasma glutamate dehydrogenase (GD) (E.C. 1.4.1.3) activity, of 0-8 IU/L, was established for the cockatiel (Nymphicus hollandicus). An automated modification of a commercial manual assay was used. This enzyme is considered liver specific in humans and numerous domestic animals, due to its organ distribution. A similar distribution was found in cockatiels in this study. Maximal enzyme activity was recovered from liver and kidney homogenate supernatants. Minimal activity was detected in skeletal muscle preparations. These results suggest a potential use for plasma GD activity in the evaluation of hepatocelluar injury/necrosis in cockatiels.     

组氨醇脱氢酶抑制剂的研究动态

组氨醇脱氢酶(HDH)是组氨酸生物合成过程中最后两步反应的催化酶。对组氨醇脱氢酶的结构、催化机理、组氨醇脱氢酶抑制剂等方面的研究动态进行了较为详细的综述。     

黄瓜低霜霉威残留性相关基因SDH克隆及表达

通过Solexa技术和比较基因组学方法鉴定霜霉威胁迫下黄瓜果实差异表达基因,筛选黄瓜低霜霉威残留性相关基因SDH。研究利用PCR克隆获得SDH基因全长,命名为Cs SDH。构建亚细胞定位表达载体,利用农杆菌浸润法注射烟草叶片后激光共聚焦显微镜下观察;分别用荧光定量RT-PCR方法和酶联免疫法研究高、低农残品系D9320和D0351中Cs SDH基因在农药霜霉威处理后,不同时间点、不同组织部位时空表达特征和琥珀酸脱氢酶活性。结果表明,Cs SDH基因在烟草叶片细胞中被定位在细胞膜上。黄瓜低农残品种D0351中,Cs SDH基因在果实受霜霉威胁迫后反应迅速,主要在处理前期响应表达强烈,琥珀酸脱氢酶活性显著增加,且该基因表达量显著高于其在高农残品种D9320中表达量。Cs SDH果、叶中表达量较茎中高,且各组织部位表达量高低顺序稳定,为叶果茎。黄瓜高农残品种D9320中,Cs SDH基因表达量在0.5、1、3、12 h呈现上调表达,6、9 h基因表达量差异不显著,48 h出现上调表达高峰。说明克隆得到的Cs SDH基因属农药处理前期响应基因,且该基因可能在降低黄瓜农药残留过程中发挥重要作用。试验通过研究黄瓜琥珀酸脱氢酶基因(SDH)在霜霉威胁迫下表达情况,为挖掘黄瓜低农药残留性功能基因以及探明其作用分子机制奠定基础。     

Molecular cloning,purification and immunogenicity of recombinant Brucella abortus 544 malate dehydrogenase protein

The Brucella mdh gene was successfully cloned and expressed in E. coli. The purified recombinant malate dehydrogenase protein (rMDH) was reactive to Brucella-positive bovine serum in the early stage, but not reactive in the middle or late stage, and was reactive to Brucella-positive mouse serum in the late stage, but not in the early or middle stage of infection. In addition, rMDH did not react with Brucella-negative bovine or mouse sera. These results suggest that rMDH has the potential for use as a specific antigen in serological diagnosis for early detection of bovine brucellosis.     

植物表达载体pGMAR-BADH的构建

将甜菜碱醛脱氢酶基因BADH和植物表达载体pGMAR通过内切酶BamHI和KpnI双酶切,T4连接酶进行连接反应。重组质粒在大肠杆菌菌株DH5α内扩增,提取并纯化质粒。经鉴定,基因BADH已被完整、正确的插入到pGMAR载体中,并成功将BADH插入到载体pGMAR的两个MAR序列之间。     

艾纳香脱氢酶基因家族的生物信息学分析

采用RT-PCR和RACE（Rapid amplification of cDNA ends）技术,从艾纳香（Blumea balsamifera (L.) DC.）叶片中克隆到4条编码艾纳香脱氢酶（BbADH1、BbADH2、BbADH3、BbADH4）基因的cDNA序列,并对4条核苷酸及其编码的氨基酸序列进行生物信息学分析。结果显示:4条艾纳香脱氢酶序列开放阅读框均在900 bp左右,蛋白质等电点（pI）值在5.0~9.0之间,含量最多的氨基酸为亮氨酸（Leu）,最少的为色氨酸（Try）,具有明显的疏水区和亲水区,N端未发现信号肽,且无跨膜区;同源性比对结果显示,艾纳香BbADH蛋白与其他植物中ADH蛋白具有高度的相似性,且具有脱氢酶的特征功能域;系统发育分析表明,艾纳香（B. balsamifera (L.) DC.）BbADH1和BbADH3同处于一个分支,且与胡杨（Populus euphratica Oliv.）PeADH物种亲缘关系较近,而艾纳香BbADH4和BbADH2处于不同分支,且分别与葡萄（Vitis vinifera）VvADH和烟草（Nicotiana tabacum）NtADH物种亲缘关系较近。     

高温胁迫对棘胸蛙蝌蚪抗氧化酶活力的影响

实验利用水温从18~30℃骤升和缓升两种模式,高温胁迫处理棘胸蛙(Quasipaa spinosa)蝌蚪后,提取其尾部肌肉和内脏团的组织液,进行乳酸脱氢酶(LDH)、谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、碱性磷酸酶(AKP)等酶活力和丙二醛(MDA)含量测定。结果表明,棘胸蛙蝌蚪尾部肌肉提取液的LDH活力显著高于内脏团(P0.01);高温胁迫下棘胸蛙蝌蚪尾部肌肉和内脏团提取液的LDH活力显著提高(P0.01)。高温胁迫下棘胸蛙蝌蚪尾部肌肉和内脏团的GSH-Px活力均显著降低(P0.01,P0.05),且水温骤升模式下的内脏团GSH-Px活力显著高于缓升模式(P0.01)。在30℃高温胁迫时,棘胸蛙蝌蚪尾部肌肉和内脏团SOD活力均显著降低(P0.05,P0.01),且水温骤升模式的棘胸蛙蝌蚪尾部肌肉和内脏团SOD活力均高于缓升模式(P0.05,P0.01)。高温胁迫下CAT活力均显著下降(P0.01),且缓升模式下的棘胸蛙蝌蚪CAT活力显著高于骤升模式(P0.05,P0.01)。在两种升温模式下,高温胁迫对尾部肌肉的AKP活力均无显著影响;而在骤升模式下,高温胁迫的棘胸蛙蝌蚪内脏团的AKP活力显著提高(P0.05)。高温胁迫下的棘胸蛙蝌蚪尾部肌肉和内脏团MDA含量均显著升高(P0.01),骤升模式下高温胁迫的棘胸蛙蝌蚪内脏团的MDA含量显著高于尾部肌肉(P0.01)。