钙蛋白酶系统在肌肉生长和肉品嫩化方面的研究

钙蛋白酶系统主要由钙蛋白酶(calpain)及钙蛋白酶抑制蛋白(calpastatin)组成,calpain是存在于细胞质中的依赖于Ca2+的中性蛋白酶,calpastatin是钙蛋白酶的内源抑制蛋白。近年的研究表明,calpain是细胞质中主要的蛋白水解酶,在肌原纤维蛋白降解中起着重要的作用。肌肉增长和宰后嫩度的变化与蛋白质水解程度密切相关。因此,钙蛋白酶系统的活性会影响畜禽肌肉增长和肉的嫩度。文中综述了钙蛋白酶系统各种酶的结构及其如何在肌肉生长和肉的嫩化中起作用。     

动物钙蛋白酶系统基因与肉质嫩度关联研究进展

钙蛋白酶系统由钙激活中性蛋白酶I(μ-calpain,calpain l,CAPN1)、钙激活中性蛋白酶Ⅱ(m-calpain,calpain 2,CAPN2)及其内源性抑制剂钙蛋白酶抑制蛋白(calpastatin,CAST)3个部分组成,钙蛋白酶的活性会影响畜禽肌肉增长和肉的嫩度.对钙蛋白酶系统的特性、作用机理及其对肉质的影响进行了综述,并对其应用前景进行讨论.     

钙蛋白酶系统与肌肉增长及嫩度的相关性研究

钙蛋白酶(calpain)系统主要包括钙蛋白酶、钙蛋白酶抑制蛋白(calpastatin)和钙蛋白酶激活蛋白(calpain activator)。近年的研究表明,calpain是细胞质中主要的蛋白水解酶,此系统参与了调控肌原纤维蛋白的降解并在其中发挥了关键性的作用,肌肉增长和宰后嫩度的变化与蛋白质的周转代谢密切相关。同时阐述了钙蛋白酶系统的结构、功能及活性调节与肉质的关系等。     

牛钙蛋白酶抑制蛋白基因（CAST）的多态性的研究

钙蛋白酶抑制蛋白基因calpain是存在于细胞质中的依赖于Ca2＋的钙中性蛋白酶，蛋白酶系统是主要的蛋白质降解物。calpastatin是钙蛋白酶的内源性抑制蛋白。研究表明，Calpastatin在肌原纤维蛋白降解中起着重要作用。因此，对肌肉生长和嫩度有重要影响。本文综述了钙蛋白酶抑制蛋白的结构组成，对肉嫩度影响的机理和钙蛋白酶抑制蛋白基因的定位。     

钙蛋白酶系统与猪肉嫩度的相关性研究

钙蛋白酶系统是影响肌肉生长和宰后肉嫩化的一个重要因素,主要由钙蛋白酶（μ-calpain和m-calpain）、钙蛋白酶抑制蛋白（calpastatin,CAST）及骨骼肌特异性钙蛋白（muscle specific calpain,P94）组成,其参与调控肌原纤维蛋白的降解,并影响肉品嫩度。本文概述了钙蛋白酶系统结构、功能及其对肉品嫩度的影响。     

钙蛋白酶抑制蛋白对猪肉品质的影响

钙蛋白酶蛋白系统是影响肌肉生长和宰后肉嫩化的一个重要因素,主要由钙蛋白酶(μ-calpain和m-calpain)、钙蛋白酶抑制蛋白(calpastatin,CAST)及骨骼肌特异性钙蛋白酶组成,钙蛋白酶抑制蛋白是一种内源性专一抑制钙蛋白酶活性的蛋白,参与了调控肌原纤维蛋白的降解并在其中发挥了关键作用。本文概述了钙蛋白酶抑制蛋白的结构、功能及其对肌肉蛋白质的增加、提高肉嫩度的作用。     

钙蛋白酶系统研究进展

钙蛋白酶系统在人和动物体内广泛存在,是高度复杂、高度调控的体系。钙蛋白酶系统由钙蛋白酶（calpain）I（CAPN1）、钙蛋白酶II（CAPN2）、骨骼肌特异性蛋白（muscle specific calpain,CAPN3）和钙蛋白酶抑制蛋白（calpastatin,CAST）组成。钙蛋白酶系统在动物屠宰后肉的成熟嫩化及人和动物正常生理过程的维持中起重要作用。对钙蛋白酶系统的作用、各成分分子结构、基因结构、作用机制、调控机制等做了综述,并讨论了其应用前景及今后的研究方向。     

钙蛋白酶系统研究进展

钙蛋白酶系统在人和动物体内广泛存在,是高度复杂、高度调控的体系。钙蛋白酶系统由钙蛋白酶（calpain）I（CAPN1）、钙蛋白酶II（CAPN2）、骨骼肌特异性蛋白（muscle specific calpain,CAPN3）和钙蛋白酶抑制蛋白（calpastatin,CAST）组成。钙蛋白酶系统在动物屠宰后肉的成熟嫩化及人和动物正常生理过程的维持中起重要作用。对钙蛋白酶系统的作用、各成分分子结构、基因结构、作用机制、调控机制等做了综述,并讨论了其应用前景及今后的研究方向。     

钙蛋白酶抑制蛋白对畜禽肉品质影响的研究进展

钙蛋白酶抑制蛋白(calpastatin, CAST)是由CAST基因编码,是内源性专一抑制钙蛋白酶(calpain, CAPN)活性的抑制蛋白,是CAPN系统家族成员之一,可以调节脊椎动物体内CAPN活性。CAST能控制肌原纤维中蛋白质降解,影响肌细胞的生长速度及肌肉嫩度。CAST活性减弱或活化CAPN都能增加肌肉嫩度,从而改善肉品质。CAST基因可作为猪、牛、羊改善肉品质的候选基因。文章综述了CAST结构、CAST调控机制,分析了其对畜禽肉品质的影响,以期为推进CAST在改善畜禽肉品质中的进一步应用提供参考。     

钙蛋白酶抑制蛋白在动物营养中的研究进展

钙蛋白酶抑制蛋白(calpastatin)是一种有着多种功能的内源抑制剂,它通过抑制钙蛋白酶(calpain)的活性而发挥作用,参与骨骼肌的生长调节与肌肉嫩度的调控。本文综述了钙蛋白酶抑制蛋白的生物学结构、活性调控机理以及其与营养的关系等。     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein     

Avian brood parasitism — a growing research area in behavioral ecology (part Ⅱ)

正We are pleased to publish the second special issue on avian brood parasitism and to be responsible guest editors for the two special issues of Chinese Birds (Vol. 3, No. 4, 2012 and Vol. 4, No. 1, 2013), entitled "Avian Brood Parasitism - A Growing Research Area in Behavioral Ecology". The first issue was published in December 2012. The goal of the two special issues is to publish accumulated knowledge and some of the recent developments in     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -