Gene constitution of South-East Asian native chickens, commercial chickens and jungle fowl using polymorphisms of four calpain genes

The gene constitution of polymorphisms of the four calpain genes (µ‐calpain, m‐calpain, p94, and µ/m‐calpain) were analyzed in South‐East Asian native chickens, White Leghorn and Broiler commercial chickens, and Red and Green jungle fowl. Polymorphisms were detected at all loci in chickens and Red jungle fowl, but only for CAPN1 (µ‐calpain gene) in Green jungle fowl. CAPN2 and CAPN1.5 are linked on chicken chromosome 3, and the genotype for these loci were treated as haplotype. Some combinations of calpain loci were tested using principal component analysis, and the best combination (CAPN1, CAPN3, and CAPN1.5) was determined. The proportion of polymorphic loci (P_poly) and heterozygosity (H?) were 1.00 and 0.316–0.465 in domestic chickens and red jungle fowl, and 0.33 and 0.137 in Green jungle fowl, respectively. G_ST values suggested that the degree of subdivision among native chickens was relatively low except for Thailand, which was highest. Pair‐wise F_ST testing, dendrogram and principal component analysis from the results of calpain loci showed that the four South‐East Asian native and commercial chicken populations were close genetically.     

影响肉质嫩度calpain基因的研究进展

钙蛋白酶是一种存在于细胞内的非溶酶体性的限制性蛋白水解酶,在宰后肉质的嫩化和肉质的改善过程中起着重要的作用,本文对钙蛋白酶分类、结构、调节作用、嫩化机制及分离纯化方法等方面进行了阐述。     

鸡钙蛋白酶及其基因的分子生物学研究进展

钙蛋白酶是与肉质性紧密相关的一个候选基因,对鸡的钙蛋白酶及相关基因的分子生物特性及其与一些性状的相关性的研究进展进行了综述。     

Calpain 1．5 mRNA表达量与鸭肉嫩度关系的研究

选择60只70日龄左右、体重相似高邮鸭、樱桃谷鸭和番鸭,屠宰后取左半膛测定剪切力,用荧光实时定量PCR法,以β-actin基因为内标,检测calpain 1.5基因的表达量与嫩度的关系,并进行品种间比较.通过对3个品种鸭剪切力的测定.高邮鸭>樱桃谷鸭>番鸭,差异均不显著(P>0.05);3个品种都是胸肉<腿肉,即胸肉嫩度大于腿肉,差异显著(P<0.05).说明3个品种鸭肉嫩度由高到低依次为番鸭>樱桃谷鸭>高邮鸭.鸭胸肉与腿肉calpain 1.5基因mRNA表达量差异显著(P<0.05).肉的剪切力和calpain 1.5基因mRNA相对表达量呈对数关系(0.5calpain 1.5基因作为嫩度的侯选基因,calpain 1.5mRNA表达量与鸭肉的嫩度呈正相关.     

猪CAPN3基因的克隆及PCR-SSCP分析

calpain3在肌肉组织中的特异表达,其活性显著影响宰后肉的嫩化。研究利用比较基因组学的方法首次克隆了猪CPAN3基因的内含子16~23,并利用PCR-SSCP方法在外显子1中寻找到1个插入/缺失突变和1个碱基替代,为进一步分析其变异和肉质的关系并进而确定遗传标记提供了基础。     

高氧气调包装对宰后猪肉蛋白质氧化、钙蛋白酶活性及蛋白质降解的影响

【目的】研究高氧气调包装（HiOx,80% O₂/20% CO₂）对宰后猪肉蛋白质氧化、钙蛋白酶活性及蛋白质降解的影响,探讨高氧气调包装影响猪肉品质的内在机制。【方法】选取12条冷却（4℃）24 h后的杜洛克×长白×约克夏三元杂交猪背最长肌,分别进行高氧气调包装和真空包装（VP）,4℃冷库贮藏,分别在1、4、6 d测定羰基含量及分布、巯基含量、肌节变化、钙蛋白酶活性、肌联蛋白及肌钙蛋白-T降解变化。【结果】高氧气调包装组羰基含量高于真空包装组且贮藏第4和6天差异显著（P＜0.05）。贮藏第1和4天,高氧气调包装组肌细胞外围出现羰基氧化荧光信号,荧光以靠近细胞膜处密度更高,并且逐渐向细胞内部扩散;贮藏第6天,高氧气调包装组细胞膜呈高亮荧光圈,胞内荧光增强,而真空包装组荧光信号较弱。贮藏第6天,高氧气调包装组巯基含量显著低于真空包装组（P＜0.05）。真空包装组宰后肌节M线弱化、A带模糊、肌原纤维Z线断裂;高氧气调包装组肌节结构相对完整。高氧气调包装组在贮藏第1天钙蛋白酶活性显著低于真空包装组（P＜0.05）;高氧气调包装抑制了肌联蛋白和肌钙蛋白-T的降解,且在贮藏第4和6天差异显著（P＜0.05）。【结论】高氧气调包装能够显著提高宰后猪肉蛋白质氧化程度,抑制钙蛋白酶活性发挥及其底物蛋白质的降解。     

Differences in calpain system,desmin degradation and water holding capacity between commercial Meishan and Duroc × Landrace × Yorkshire crossbred pork

The objective of this study was to examine the differences in calpain system, desmin degradation, pH values and water holding capacity (WHC) between muscles of commercial Meishan and Duroc × Landrace × Yorkshire crossbred pigs. Meishan pork presented better WHC evidenced by lower purge loss at days 1 and 3 and less centrifugation loss at day 1 post mortem (P < 0.05). pH values at 45 min post mortem in Meishan pork were significantly higher compared to crossbred pork (P < 0.05). Calpain‐1 messenger RNA (mRNA) expression was lower in Meishan pork compared to that from crossbred pork (P < 0.05). Additionally, calpain‐1 activity, the ratio of calpain‐1 to calpastatin activity and desmin degradation were lower in Meishan pork compared to those from crossbred pork samples (P < 0.05). The results indicate that the calpain system including mRNA expression and activity were different between commercial Meishan and crossbred pork resulting in difference in the degree of desmin degradation during post mortem aging. pH values at 45 min and 24 h post mortem rather than calpain activity and desmin degradation could explain the higher water holding capacity in commercial Meishan pork.     

Effect of negative dietary cation‐anion differences on carcass characteristics and beef tenderness of Japanese Black steers

Lowering dietary cation‐anion differences (DCAD) can enhance responsiveness to Ca‐homeostatic hormones and increase Ca availability, which might have potential to activate a Ca‐dependent protease, calpain, and to enhance postmortem myofibrillar proteolysis. In this study, we investigated the effects of DCAD manipulation on calpain activity and beef tenderness in Japanese Black cattle which are characterized by their high marbling. Thirty‐six Japanese Black steers were allotted to one of two treatments: (i) control (CON; DCAD +6.09 mEq/100 g of dry matter (DM)) or (ii) negative DCAD (NEGD; DCAD ?8.27 mEq/100 g DM) for 70 days before slaughter. Lowering DCAD decreased DM and energy intake (P < 0.01) even though it did not negatively affect the growth performance or carcass characteristics. In NEGD, urine pH was decreased by acidification caused by the negative DCAD (P < 0.01). Calpain activities tended to be improved in NEGD (P = 0.09), but Warner‐Bratzler shear force values were not affected by treatment. Although calpain activities tended to improve, lowering DCAD to ?8.27 for 70 days before slaughter was insufficient to enhance beef tenderness in Japanese Black steers.     

Linkage mapping of four chicken calpain genes

Calpains are intracellular Ca²⁺‐dependent proteases and enzymes that contribute to growth and meat quality. In the present study, we identified polymorphisms in four calpain genes (CAPN1, CAPN2, CAPN3, and CAPN1.5) expressed ubiquitously in chicken using polymerase chain reaction‐restriction fragment length polymorphism, and mapped them using two backcross families (East Lansing (EL) and Kobe University (KU)). CAPN2 and CAPN1.5 mapped to two locations on chromosome 3 about 30 cM apart, while CAPN3 mapped to chromosome 5. CAPN1 was linked to a previously unlinked microsatellite marker LEI0140 to form a new linkage group called E66. CAPN2 and CAPN3 extend the amount of conserved synteny between chicken chromosome 3 and human chromosome 1, and between chicken chromosome 5 and human chromosome 15, respectively. Although CAPN2, CAPN3, and CAPN1.5 were found in the University of California Santa Cruz chicken genome browser gateway, CAPN1 and LEI0140 were not in specific genomic positions.