Involvement of μ/m‐calpain in the proteolysis and meat quality changes during postmortem storage of chicken breast muscle

The objective of this study was to investigate the role of calpain isotypes, especially poultry‐specific μ/m‐calpain in the proteolysis and meat quality changes of chicken breast muscle during postmortem storage. Calpain activity was detected by casein zymography, while the degradation of titin, desmin and Troponin‐T was analyzed by sodium dodecyl sulfate – polyacrylamide gel electrophoresis and western blot. Meat quality indicators such as water holding capacity and tenderness were also studied. The correlation analysis between calpain activity, proteolysis and the changes in meat quality indicators indicated that there were strong correlations for μ‐calpain during the first 12 h of storage, while such strong correlations for μ/m‐calpain were only found in samples stored from 12 h to 7 days. Our study suggested that μ‐calpain played a major role in meat quality changes while μ/m‐calpain could also be involved but played a limited role in the proteolysis and meat quality changes during 12 h to 7 days postmortem storage of chicken breast muscle.     

基于农业信息化理论的农业现代化研究

农业现代化是我国社会主义现代化建设的重要战略目标，农业信息化是农业现代化的重要标志和组成部分。基于农业信息化与农业现代化的概念、内涵、关系与作用，提出了大力发展农业信息化，促进农业现代化的对策。     

Farmer participation in irrigation – 20 years of experience and lessons for the future

This article examines trends in the understandingof and policies toward farmer participation in irrigationmanagement over the past 20 years, with special attention toexperiences with induced participation and management transferprograms in the Philippines, Sri Lanka, Pakistan, Senegal,Columbia Basin USA, and Mexico. Key lessons relate to the valueof social organizers as catalysts; the role of the irrigationagency as partner; and the enabling conditions for participation.As levels of income and infrastructure rise, we can expect moreformal organizations that enable farmers to deal with bankaccounts, service contracts, water rights, water markets, andadvanced technology in irrigation systems. The impact ofparticipation on irrigation performance needs to be evaluated notjust in terms of reductions in government costs, but by whetherimprovement in physical structures and farmers control overwater are great enough to offset the farmers costs ofparticipating.     

转pepc基因籼稻恢复系“N175”产量相关性状分析

比较了转甘蔗pepc基因的籼稻恢复系“N175”植株及其非转基因对照的光合效率和产量相关性状,结果表明：转基因植株的光合效率、单株穗数、千粒重、单株产量等性状有较大提高.说明甘蔗epc基因在水稻中的异源表达可以实现增产目的.     

密度和行距配置对玉米产量及其构成因素的影响

试验以桂单162为供试材料,采用2因素裂区设计,密度为主处理,行距为副处理,研究4个种植密度下4种行距配置方式对玉米产量及其构成因素的影响。结果表明：密度、行距及密度与行距互作对玉米出籽率的影响不显著;密度、密度与行距互作对玉米结实长度影响达到极显著水平,随着密度加大结实长度越短,不同密度与不同行距配置才能对结实长度起到最大的影响作用;种植密度对穗粗影响达到显著水平,穗粗随着种植密度加大而变小;密度、行距及密度与行距互作对产量的影响达到极显著水平,4种种植行距下4000株/667m2产量最高,4个密度下60 cm 单行单株种植产量最高,桂单162以4500株/667m2,60 cm 单行单株种植产量最高。     

生态补偿中的环境成本核算研究综述

环境成本是衡量经济发展代价——环境污染与生态破坏的主要方式,也是制定生态补偿标准的重要依据之一,但现有研究中很少明确提出以环境成本为依据核算生态补偿标准。主要从环境成本入手,在全面总结国内外近期有关生态补偿标准制定以及环境成本的基础之上,对环境成本的概念和核算方法进行了概述,分析了目前环境成本核算研究中存在的一些问题,对环境成本与保护成本关系、环境成本空间化进行了讨论,认为环境成本学科综合化、核算方法科学化是未来的发展趋势,环境成本的空间化是未来的研究重点。     

Steroidogenesis in rainbow trout (Salmo gairdneri) at various preovulatory stages: changes in plasma hormone levels andin vivo andin vitro responses of the ovary to salmon gonadotropin

In order to specify the timing of some changes in ovarian steroid production during the transition from vitellogenesis to ovulation, plasma hormones levels andin vivo andin vitro responses of the ovary to salmon gonadotropin (s-GtH) or dibutyryl-cyclic adenosine mono-phosphate (db-cAMP) were recorded in relationship with the state of germinal vesicle migration in the oocyte.In vivo, a small, but significant, increase of plasma 17-hydroxy-20-dihydroprogesterone (17, 20-OH-P) level was detected earlier (at the subperipheral germinal vesicle stage) than the increase of GtH level (detectable at the peripheral germinal vesicle stage) and the decline of oestradiol-17 (E2–17) (also detectable at the peripheral germinal vesicle stage). Negative correlations were established between E2–17 levels and GtH (=–0.53) or 17,20-OH-P (=–0,43) levels while a positive correlation occurred between 17,20-OH-P and GtH levels (=+0,54).In vivo no action of GtH on the decline of E2–17 levels was detected GtH did not stimulate 17,20-OH-P production, within 72h, in females at the end of vitellogenesis stage. It had significant effect in females at other stages closer to ovulation, but the pattern of responses changed according to the stage.In vitro db-cAMP like GtH was able to stimulate 17,20-OH-P output from ovarian follicles. The greatest response was observed at the later stage. (GVBD). Testosterone output was also increased by GtH, but the lowest response was observed at the later stage (GVBD). Androstenedione output was lower than testosterone output.In vitro, a small but significant decline of E2–17 output was induced by GtH. We conclude that substantial changes occur during the very last stages prior to ovulation, both in the steroidogenic potential of the ovary and in the ovarian sensitivity to GtH. 20-oxydoreductase is probably progressively induced during GV migration when GtH basal levels are increasing but still relatively low. Without minimizing the role of discrete pulses of GtH on this induction, we could expect synergic actions of other hormones. Thus a high testosterone/oestradiol ratio in the follicle environment favours 17,20-OH-P secretion.     

猪m6A甲基化酶WTAP基因与F18大肠杆菌感染的关系

本研究旨在探讨猪m⁶A甲基化酶WTAP表达水平与大肠杆菌（E. coli）感染抗性的关系。选取35日龄苏太断奶仔猪（Sus scrofa）大肠杆菌抗性型和敏感型个体各4头,采集十二指肠和空肠组织,利用RT-qPCR检测WTAP在E. coli抗性型和敏感型个体十二指肠、空肠的表达差异,并分别利用产肠毒素大肠杆菌（F18ab、F18ac）刺激和内毒素（LPS）诱导猪小肠上皮细胞（IPEC-J2）,检测WTAP基因的表达变化。同时构建WTAP基因干扰载体并转染IPEC-J2细胞,通过菌毛定量、菌落计数以及间接免疫荧光试验检测该基因沉默对大肠杆菌黏附能力的影响。结果显示：在十二指肠和空肠组织中,WTAP基因在E. coli抗性型个体中的表达量显著高于敏感型个体（P<0.01）;并且在F18ab和F18ac刺激后表达量显著下降,与LPS诱导6 h后结果相一致（P<0.01）。沉默WTAP基因后,大肠杆菌黏附能力极显著上升（P<0.01）。本研究在细胞和个体水平上验证发现,m⁶A甲基转移酶WTAP的高表达可能有助于仔猪抗大肠杆菌感染,为进一步揭示仔猪抗大肠杆菌感染的RNA甲基化调控机制奠定基础。     

高产大豆1012与多根瘤品系0498苗期生育特性的比较

[目的]为进一步开发、利用大豆优良育种材料1012、0498提供参考。[方法]以多根瘤大豆品系0498和高产大豆品系1012为材料,比较研究了它们苗期的生育特性。[结果]在苗期,1012的株高增长比0498快,叶色值始终比0498高,单株地上部干重比0498高,单株地上部干重的增加量也比0498大,播种后30 d Rubisco含量比0498多27.5%;0498的根瘤数远比1012多,且增幅大;2个供试材料的气孔导度相差不明显。10:00～12:00时2个大豆品系的Fv/m都较大,1012的Fv/m始终比0498大。[结论]1012有较强的光合作用能力,0498具有较强的固氮潜力。     

粳型不育系津3A的开花习性初步观察

对粳型不育系津3A的日开颖比率、午前花率等开花习性进行了初步研究,结果表明:津3A开花历期约为7d,始花后第2天即进入盛花期;每日11:30—12:30为盛花时间,比C418约迟30min,在制种中应该注意适当喷施花时调节剂,提早津3A花时,使父母本盛花期、盛花时相遇,提高制种产量。