酪蛋白磷酸肽的生理功能及在饲料业上的应用前景

酪蛋白磷酸肽(CPPs)是从牛奶的酪蛋白中提取的一种生物活性肽，在中性和偏碱性环境下可提高钙的溶解度和钙溶液的稳定性，从而促进肠道对钙的吸收，还可有效促进锌、铁等其他矿物元素的吸收，本文综述了国内外酪蛋白磷酸肽的研究动态及其生理功能、作用机理、制备方法等，并展望了其在饲料业中的应用潜力。     

酪蛋白磷酸肽的生物学活性及其应用

酪蛋白磷酸肽(CPPs)是以牛奶酪蛋白为原料,经过单一或复合蛋白酶的水解,再对水解产物分离纯化后得到的含有磷酸丝氨酸簇的天然生理活性肽。酪蛋白磷酸肽能促进机体肠黏膜对钙、铁、锌、硒,尤其是钙的吸收和利用,被誉为矿物质载体。目前,酪蛋白磷酸肽是唯一促进钙吸收的活性肽,在提高机体免疫力、改善繁殖性能等方面也有重要作用。日本、德国等国家已把酪蛋白磷酸肽定为功能性食品,在我国关于酪蛋白磷酸肽的研究也越来越     

酪蛋白磷酸肽在动物钙营养中的研究进展

酪蛋白磷酸肽(CPPs)是含有成簇的磷酸丝氨酰基的生物活性肽,具有结合钙和促进钙吸收的功能。本文主要介绍酪蛋白磷酸肽在钙营养方面的研究利用情况。     

酪蛋白磷酸肽功能研究进展

近年来，已有许多具生物活性的多肽经蛋白质消化而被辩认出来，生物活性肽是近年来国内外动物营养研究的热点之一。酪蛋白磷酸肽（CaseinPhosphopeptides，CPP）是以牛奶酪蛋白为原料，经过单一或复合蛋白酶的水解，再对水解产物分离纯化后得到的含有磷酸丝氨酸簇的天然生理活性肽。CPP是目前唯一促进钙吸收的活性肽，     

酪蛋白磷酸肽的应用研究进展

酪蛋白磷酸肽是从牛乳酪蛋白中水解分离所得的一种生物活性肽。现已证明,其具有促进钙和铁等矿物元素的吸收及防止蛀牙等生理功能。     

酪蛋白磷酸肽在动物钙营养中的研究进展

酪蛋白磷酸肽(CPPs)是含有成簇的磷酸丝氨酰基的生物活性肽,具有结合钙和促进钙吸收的功能。文章主要介绍CPPs在钙营养方面的研究利用情况。     

酪蛋白磷酸肽在动物钙营养中的研究进展

酪蛋白磷酸肽(CPPs)是含有成簇的磷酸丝氨酰基的生物活性肽,具有结合钙和促进钙吸收的功能。本文主要介绍CPPs在钙营养方面的研究利用情况。     

κ-酪蛋白遗传多样性对血管紧张素Ⅰ转换酶抑制肽活性的影响

牛奶中蛋白质是生物活性肽的来源之一，这些肽在酪蛋白和乳清蛋白的消化过程中产生。因此，本试验主要研究牛奶中不同的κ-酪蛋白基因型A、B、C、E、F1、F2、G1、G2、H、I和J中活性肽对血管紧张素Ⅰ转换酶（ACE）抑制活性的影响。通过分析肛酪蛋白基因型的氨基酸序列来测定ACE抑制肽的活性。测定了已知的生物活性肽活力和其它一些κ-酪蛋白基因型巾其它肽的活性。结果表明，κ-酪蛋白基因型B和基因型C中的ASP（ACE抑制肽）的IC50（半数抑制浓度）值为242．3，     

乳中生物活性肽的研究进展

本文简要介绍了乳中的某些具有生物活性的肽类。如阿片样肽、安神麻醉肽、免疫刺激肽、抗血栓肽、酪蛋白磷酸肽、乳铁蛋白多肽等的结构与生理功能，并简要介绍了其应用前景。     

酪蛋白磷酸肽在动物营养中的研究进展

酪蛋白磷酸肽 (ＣａｓｅｉｎＰｈｏｓｐｈｏｐｅｐｔｉｄｅｓ,简称ＣＰＰ)是以牛乳酪蛋白为原料 ,经单一酶或复合酶系水解 ,再经分离纯化而得到的含有成簇的磷酸丝氨酰基的肽。钙、铁、锌在动物体内起着重要作用 ,由于饲料原料中含有大量植酸盐、纤维素、糖醛酸、藻酸钠和草酸等 ,从而阻碍了动物对钙、铁、锌等矿物质的吸收。ＣＰＰ可提高钙、铁、锌等矿物质的溶解度从而促进矿物质的吸收。另外 ,ＣＰＰ对动物免疫和繁殖也有着重要作用。1　ＣＰＰ的分子结构ＣＰＰ有α和β两种 ,它们分别由α -酪蛋白和β -酪蛋白水解生成。α -酪蛋白占牛…     

抗战时期中国共产党处理国共关系的政策、方法及原则初探

抗战时期，中国共产党处理国共关系的政策与方法，既有具体、直观的，又有抽象、隐蔽的；既讲原则的坚定性，又不缺乏方法的灵活性；既求同又存异、既统一又独立、既原则又让步、既联合又斗争，而在斗争中既有明显的斗智斗勇，也有暗藏的玄机、矛盾。抗战时期中国共产党在坚持统揽抗战全局、把握问题实质的基础上，还特别重视和遵循处理国共关系的基本原则，即利益原则和理性原则。     

Case study of copper poisoning in a British dairy herd

Following the initial diagnosis of chronic copper poisoning (CCP), the copper (Cu) status of a British dairy herd was investigated. Eight fatal cases of CCP were identified over a 17-month period, from December 1999 to May 2001, involving seven Jersey cows and one Holstein-Friesian; seven cows were dry when CCP occurred. Case diagnostic criteria were necrotising hepatopathy associated with abnormally high liver and kidney Cu concentrations. Analysis of the ration for the high-yielding Jersey cow group revealed about 50 mg Cu/kg dry matter intake (DMI). Risk factors predisposing to fatal CCP were Jersey breed, previous high yield, first two weeks of the dry period and moderately high dietary Cu (greater than 40 mg Cu/kg DMI).     

Detection of spinal ataxia in horses using fuzzy clustering of body position uncertainty

REASONS FOR PERFORMING STUDY: Subjective neurological evaluation in horses is prone to bias. An objective method of spinal ataxia detection is not subject to these limitations and could be of use in equine practice and research. HYPOTHESIS: Kinematic data in the walking horse can differentiate normal and spinal ataxic horses. METHODS: Twelve normal and 12 spinal ataxic horses were evaluated by kinematic analysis walking on a treadmill. Each body position signal was reduced to a scalar measure of uncertainty then fuzzy clustered into normal or ataxic groups. Correct classification percentage (CCP) was then calculated using membership values of each horse in the 2 groups. Subsequently, a guided search for measure combinations with high CCP was performed. RESULTS: Eight measures of body position resulted in CCP > or = 70%. Several combinations of 4-5 measures resulted in 100% CCP. All combinations with 100% CCP could be obtained with one body marker on the back measuring vertical and horizontal movement and one body marker each on the right fore- and hindlimb measuring vertical movement. CONCLUSIONS AND POTENTIAL RELEVANCE: Kinematic gait analysis using simple body marker combinations can be used objectively to detect spinal ataxia in horses.     

Effects of 2-mercaptoethanol on the solubility of copper and zinc containing proteins in liver samples from normal and chronic copper poisoned sheep

The solubility of Cu and Zn binding proteins was studied in liver samples from clinically healthy and chronic copper poisoned sheep (CCP). Homogenized liver was divided by ultracentrifugation into cytosol and pellet. The cytosol was gelfiltrated, Cu and Zn contents were determined in the eluates as well as in the pellet. Liver homogenate, cytosol and pellet were treated with 2-mercaptoethanol (ME). The resulting clear solutions were fractionated by gel filtration followed by determination of the contents of the two metals in the eluates.In CCP sheep the solubility of Cu containing proteins from the liver homogenate and pellet increased after incubation with ME.The results suggest that in CCP sheep a considerable amount of Cu containing proteins are present in an insoluble form, which to some extent is resolubilized by ME.     

The effect of a surgically created shunt between the corpus cavernosum penis and corpus spongiosum penis of stallions on erectile and ejaculatory function

OBJECTIVE: To evaluate the effect of a shunt created between the corpus cavernosum penis (CCP) and corpus spongiosum penis (CSP) on erectile and ejaculatory function of normal stallions and to verify persistence of the shunt. STUDY DESIGN: The capability of stallions to develop an erection and to ejaculate was evaluated before and after creation of a corporeal shunt. Persistence of the shunt was determined by dye injection into the CCP at necropsy. ANIMALS: Six stallions. METHODS: A CCP-CSP shunt was created in five stallions. Semen was collected before and 4 to 14 weeks after surgery, before the horses were euthanatized. Dye was injected into the CCP to determine persistence of the shunt. Dye was also injected into the CCP of a control stallion. RESULTS: All stallions had normal erectile and ejaculatory function before and after surgery. Dye, injected into the CCP, entered the CSP in three of five treated stallions, demonstrating persistence of the shunt, whereas in two stallions, dye was found only in the CCP, indicating closure of the shunt. No dye was detected in the CSP of the control stallion. CONCLUSIONS: Creation of a corporeal shunt does not interfere with normal erection and ejaculation of stallions. Shunt closure is not necessary for stallions to retain normal erectile and ejaculatory function. CLINICAL RELEVANCE: Failure of a stallion affected by priapism to achieve normal erection or to ejaculate after creation of a corporeal shunt would likely be because of damage to corporeal tissue than from an effect of the shunt.     

Clinical observations of cattle and buffalos with experimentally induced chronic copper poisoning

The susceptibility of cattle and buffalos to chronic copper poisoning (CCP) was compared by using cattle (n = 10) and buffalo (n = 10) steers distributed into two copper supplemented (n = 6) and two control (n = 4) groups. Supplemented animals received 2 mg copper (Cu)/kg body weight daily for one week, with an additional 2 mg weekly until the end of the experiment (day 105). Three liver biopsies (day 0, 45, and 105) were obtained for mineral analyses; clinical examinations and blood samples were obtained every 15 days. Three supplemented cattle and two buffalos with typical manifestations of CCP died. There were no differences in the frequency of mortality between cattle and buffalos; hepatic copper concentration was higher in cattle than buffalos. These findings suggest that buffalos and cattle might be equally susceptible to CCP. However, buffalos accumulate less liver copper than cattle and have a lower threshold of hepatic Cu accumulation, which leads to clinical manifestation of CCP.     

Angiography of the crus penis in the ram and buck during erection

Serial angiography was used to determine blood flow patterns to the penis of rams and bucks. Animals were anesthetized and the internal pudendal artery was catheterized so that contrast medium could be injected toward the crus penis area. By comparing vascular patterns of the ram and buck during erection, it was found that flow patterns of the corpus cavernosum penis (CCP) and corpus spongiosum penis (CSP) were similar for both species. Contraction of the ischiocavernosus muscles occluded the arterial inflow and venous outflow to the CCP, making it a closed system during peak erection. However, during erection, the contrast medium continued to flow into the CSP, showing that it is not a closed system. In the vasodilatation phase, the CSP usually filled before and more intensely than did the CCP.     

酱卤鸭脖加工过程中危害分析与关键控制点确定

本研究应用HACCP的基本原理与方法,通过对酱卤鸭脖生产过程中的微生物、亚硝酸盐、盐分、肌肉pH值等指标的测定,从生物、化学两方面来分析酱卤鸭脖生产各工艺点中,对酱卤鸭脖质量可能产生的潜在危害,从而确定关键控制点(CCP),CCP为清洗、卤制、包装、灭菌.此外,针对显著危害制定HACCP计划表,为确保酱卤鸭脖质量和安全提供依据.     

Genetic and splice variations of Bos taurus CD46 shift cell permissivity to BVDV, the bovine pestivirus

The pestivirus bovine viral diarrhea virus (BVDV) is known to bind to the CD46 molecule, which subsequently promotes entry of the virus. Mapping of the BVD-virion-binding site has shown that two peptides, 66EQIV69 and 82GQVLAL87, located on antiparallel beta sheets in the most distal complement control protein module (CCP1), provide the attachment platform. In the present study, we reveal the existence of ten distinct allelic versions of the CCP1 module, varying significantly in frequency among taurine and indicine races. A complex mRNA splicing pattern was also evidenced for bovine CD46, generating three different serine-threonine-proline segments and five different cytoplasmic domains. The four most frequent allelic variants and the six splice variants were then expressed in BVDV-nonpermissive porcine cells and the quantity of progeny virions generated by each cell preparation was measured 48 h post-infection. As expected, ectopic expression of the 10 bovine CD46 isoforms rendered the PK15 cells permissive to BVDV, as attested by the 100,000-fold greater recovery of virions from these cells than from non-transfected cells. This permissivity increase was significantly lower (-33%, P<0.001) when the canonical CCP1 was replaced with the variant most frequent in zebus, suggesting positive or negative selection of this allele in the latter and in the former, respectively. The predicted secondary structure of this variant suggests that the measured loss of function is due to the disappearance of one of the two beta sheets constituting the BVDV attachment platform. On the other hand we showed that for a given CCP1, the titer recovered at 48 hpi also depended on the nature of the CD46 cytoplasmic domain (P<0.001). This result implies that virus binding generates a cytoplasmic-tail-dependent outside-in signal that determines permissivity to BVDV.     

遮阴对4种豆科牧草光合特性的影响

摘要：研究豆科牧草的耐阴特性,以期为林下种草提供耐阴草种,在不同遮阴处理条件下对紫花苜蓿(Medicago sativa)、草木樨(Melilotus suaveolens)、白三叶(Trifolium repens)和沙打旺(Astragalus adsurgens)4种豆科牧草的光合特性指标进行了测定。结果表明,紫花苜蓿的气孔导度(Gs)、蒸腾速率(Tr)在透光率为60％处理下受影响较小,随着光强减弱,光饱和点（LSP）、光补偿点(LCP)和表观量子效率（AQY）降低,CO2补偿点(CCP)和饱和点(CSP)均呈增加趋势,羧化效率（CE）逐渐减小;白三叶的Gs和Tr在透光率较低的23％处理下下降明显,LSP和LCP很低,AQY较高,CSP与对照（不遮阴）基本一致,CCP较小,CE逐渐减小;草木樨的各光合指标在不同程度的遮阴下均变化较小;沙打旺随着光强的减弱LSP和LCP减小,AQY仅在透光率60％处理下高于对照,CSP 和CCP值较低,CE减小。4种豆科牧草中白三叶具有较强的耐阴性,草木樨在一定程度的遮阴下具有较强的适应性,紫花苜蓿耐阴性一般,而沙打旺则仅在透光率为60％的处理下长势较好。