类阿片肽对山羊生殖内分泌的调节Ⅱ．吗啡和纳洛酮在体外对促性腺激素的影响

利用含早卵泡期山羊血清或中黄体期山羊血清的培养液，对山羊腺垂体细胞进行２４ｈ体外培养，并在培养液中分别加入阿片受体兴奋剂——盐酸吗啡和其拮抗剂——盐酸纳洛酮，研究了类阿片肽对山羊垂体细胞分泌促性腺激素功能的影响。结果表明，在两种培养条件下，吗啡或纳洛酮对垂体促性腺激素的分泌均无显著影响（Ｐ＞０．０５）。因而认为，在山羊，类阿片肽对垂体细胞促性腺激素的分泌无直接调节作用。     

类阿片肽对山羊生殖内分泌的调节Ⅲ．吗啡和纳洛酮对促性腺激素的影响

以周期母山羊为研究对象，在其中黄体期和早卵泡期注射阿片受体兴奋剂吗啡和阿片受体拮抗剂纳洛酮．研究了类阿片肽对垂体促性腺激素分泌的影响。结果表明，在中黄体期注射吗啡引起ＬＨ分泌波幅度和血浆平均水平显著降低（Ｐ＜０．０５），注射纳洛酮使ＬＨ血浆平均水平显著升高（Ｐ＜０．０５）。而在早卵泡期，注射吗啡和纳洛酮，只分别降低和升高血浆ＬＨ水平（Ｐ＜０．０５），对其分泌波幅度无显著影响（Ｐ＞０．０５）。在以上２种生理状态下，吗啡和纳洛酮对ＦＳＨ分泌均无显著影响（Ｐ＞０．０５）。因而认为，在山羊，体内类阿片肽参与ＬＨ分泌的调节。     

Insulin-like growth factor-I, passive immunity transfer, and stereological characteristics of small intestine of newborn calves

This study evaluated the concentration of insulin‐like growth factor (IGF)‐I present in the mammary secretions, its relation with changes in serum IGF‐I and immunoglobulin (Ig)G, and intestinal mucosa alterations of 42 calves during the first week of life. Cows were randomly assigned to two groups, treated and control, with 21 animals in each. The treated group was injected with 500 mg recombinant bovine somatotropin (rbST) at day ?35 relative to predicted calving date. Newborn calves were randomly assigned to a 2 × 3 factorial scheme: dams group and slaughter date (at birth, 2 and 7 days of life). IGF‐I concentration was higher in the colostrum of treated cows (P < 0.05), but did not differ in the subsequent mammary secretions. Immunoglobulin G concentration in colostrum and subsequent mammary secretions did not differ between groups (P > 0.05). No differences were found in calf serum IGF‐I levels from birth to the seventh day or serum immunoglobulin G concentration after 24 h of life (P > 0.05). IGF‐I colostrum levels observed in this study did not affect the small intestine morphometry. The segment from the middle jejunum showed higher mucosa partial volume (Vv) at birth and 7 days old compared to other segments, and at just 2 days of age this segment reduced its Vv, not differing from other segments of the same date.     

家蝇抗菌肽提取及对鸡大肠杆菌病药效试验

体外抑菌试验结果证明抗菌肽对O1型血清大肠杆菌的药敏抑菌圈直径为19.3±0.32mm,以O1型大肠杆菌感染14日龄岭南黄肉用雏鸡,24 h后分别用抗菌肽高、中、低剂量及环丙沙星混饮给药,以比较其疗效。通过临床观察、尸体解剖、细菌检验结果表明,试验药物组与感染对照组差异极显著(P<0.01),即试验药物对鸡大肠杆菌病有良好疗效;抗菌肽高、中剂量与环丙沙星疗效相当(P>0.05),且不影响鸡只的正常增重(P>0.05)。     

Natriuretic peptide system regulation in granulosa cells during follicle deviation and ovulation in cattle

Natriuretic peptides (NPs) are known to regulate reproductive events in polyovulatory species, but their function and regulation in monovulatory species remain to be fully characterized. Using a well‐established in vivo model, we found that bovine granulosa cells from follicles near the deviation stage express mRNA for the three NP receptors (NPR1, NPR2 and NPR3), but not for NP precursors (NPPA, NPPB and NPPC). The abundance of NPR3 mRNA was higher in dominant compared to subordinate follicles at the expected time of follicular deviation. After deviation, mRNA for all NP receptors was significantly more abundant in the dominant follicle. Intrafollicular inhibition of oestrogen receptors downregulated NPR1 mRNA in dominant follicles. In granulosa cells from preovulatory follicles, NPPC mRNA increased at 3 and 6 h after systemic GnRH treatment, but decreased at 12 and 24 h to similar levels observed in samples collected at 0 h. After GnRH treatment, NPR1 mRNA was upregulated at 24 h, NPR3 mRNA gradually decreased after 3 h, while NPR2 mRNA was not regulated. The mRNA expression of the enzyme FURIN increased at 24 h after GnRH treatment. These findings revealed that the expression of mRNA encoding important components of the NP system is regulated in bovine granulosa cells during follicular deviation and in response to GnRH treatment, which suggests a role of NP system in the modulation of these processes in monovulatory species.     

Multi-centered investigation of a point-of-care NT-proBNP ELISA assay to detect moderate to severe occult (pre-clinical) feline heart disease in cats referred for cardiac evaluation

ObjectiveTo prospectively evaluate the diagnostic accuracy of a point-of-care (POC) N-terminal pro-B-type natriuretic peptide (NT-proBNP) ELISA to assess the likelihood of moderate to severe occult heart disease (OcHD) in a clinical population of cats suspected to have heart disease.AnimalsOne hundred and forty-six asymptomatic client-owned cats with a heart murmur, gallop rhythm, arrhythmia, or cardiomegaly.MethodsPhysical examination, blood pressure measurement and echocardiography were performed prospectively. Point-of-care ELISA was visually assessed as either positive or negative by a reader blinded to the echocardiographic results.ResultsForty-three healthy cats, 50 mild OcHD, 31 moderate OcHD, 6 severe OcHD, and 16 cats equivocal for OcHD were examined. Cats with OcHD included 65 with hypertrophic cardiomyopathy, 6 with restrictive or unclassified cardiomyopathy, 1 with arrhythmogenic right ventricular cardiomyopathy, and 15 with non-cardiomyopathic forms of heart disease. Point-of-care ELISA differentiated cats with moderate or severe OcHD with sensitivity/specificity of 83.8%/82.6% and overall accuracy of 82.9%. Positive POC ELISA increased likelihood of moderate or severe OcHD by a factor of 4.8 vs. those that tested negative. Point-of-care ELISA differentiated cats with moderate or severe cardiomyopathic OcHD with sensitivity/specificity of 88.6%/81.3% and overall accuracy of 83.2%.ConclusionIn a select sample of cats referred for cardiac evaluation, positive POC NT-proBNP ELISA increases likelihood of moderate to severe OcHD while negative POC NT-proBNP ELISA result excludes moderate to severe OcHD.     

Antifreeze proteins in the urine of marine fish

Several species of marine teleosts have evolved blood plasma antifreeze polypeptides which enable them to survive in ice-laden seawater. Four distinct antifreeze protein classes differing in carbohydrate content, amino acid composition, protein sequence and secondary structure are currently known. Although all of these antifreezes are relatively small (2.6–33 kd) it was generally thought that they were excluded from the urine by a variety of glomerular mechanisms. In the present study antifreeze polypeptides were found in the bladder urine of winter flounder (Pseudopleuronectes americanus), sea raven (Hemitripterus americanus), ocean pout (Macrozoarces americanus) and Atlantic cod (Gadus morhua). Since the plasma of each of these fish contains a different antifreeze class it would appear that all four classes of antifreeze can enter the urine. The major antifreeze components in the urine of winter flounder were found to be identical to the major plasma components in terms of high performance liquid chromatography retention times and amino acid composition. It is concluded that plasma antifreeze peptides need not be chemically modified before they can enter the urine.     

基于Box Behnken响应面设计优化制备鸢乌贼抗氧化肽的研究#br#

以印度洋鸢乌贼(Symplectoteuthis oualaniensis)胴体分离蛋白为原料,基于分子量分布和营养价值分析,优化制备抗氧化肽的酶解工艺参数。碱溶酸沉法从鸢乌贼胴体提取分离蛋白;以底物浓度、酶底比、酶解时间等3个因素为单因素实验;Box-Behnken中心法则设计响应面实验;DPPH自由基清除率结合水解度为响应指标。鸢乌贼胴体分离蛋白相对分子量分布在30~240 kDa;必需氨基酸占总氨基酸42.56%;最佳酶解工艺参数是底物浓度4%、酶底比9 U·mg^-1、酶解时间4 h。5 mg·mL^-1的鸢乌贼胴体分离蛋白酶解物的DPPH自由基清除率为55.60%,羟自由基清除率为53.21%,ABTS自由基清除率为40.12%。鸢乌贼胴体分离蛋白符合FAO/WHO世界卫生组织提出的理想蛋白营养价值模式,鸢乌贼胴体能制备出营养价值高和抗氧化活性强的海洋功能蛋白肽。     

高压脉冲电场技术提高红松籽抗氧化肽活性

为了研究用高压脉冲电场技术(pulsed electric field,PEF)提高红松子抗氧化肽活性的效果,该文以分子量1~3k Da的红松籽多肽为试验原料,以2,2-二苯基-1-苦基肼(2,2-diphenyl-1-picrylhydrazyl,DPPH)清除率为衡量指标,借助单因素和响应面试验设计方法,优选高压脉冲电场技术处理红松籽抗氧化肽的最佳工艺参数。研究发现,当电场强度11.5 k V/cm,脉冲频率1 500 Hz,流速4.8 m L/min时,PEF处理的红松籽抗氧化肽粉的DPPH清除率为86.93%±0.31%,比未经PEF处理的DPPH清除率68.16%±0.25%,提高了18.77%;通过中红外色谱技术(mid-infrared spectroscopy,MIR)分析了最佳PEF处理的1-3 k Da红松籽抗氧化肽粉,发现其二级结构中R2C=CH2键和-CH3发生改变,研究结果为探究PEF技术提高抗氧化肽的机理提供参考。     

海洋动物抗菌肽的研究进展

随着人们对食品安全的要求越来越高,抗菌肽因相对于抗生素而言具有不产生抗药性的主要特点而越来越引起人们的关注.本文论述了海洋动物抗菌肽的研究进展、作用机理以及对其在水产养殖中应用前景.