拉曼光谱检测脆肉草鱼肌肉脆度

脆度是脆肉草鱼品质重要检测指标之一,过度脆化的脆肉草鱼会出现溶血、缺氧和一些器官的病变。为研发出一种检测脆肉草鱼脆度的方法,实验提出一种基于拉曼光谱技术检测脆肉草鱼脆度的方法。首先,通过对不同脆化时间的脆肉草鱼拉曼光谱进行PCA分析,结果显示,拉曼光谱能够应用于不同脆化时间脆肉草鱼脆度鉴别。肌肉总蛋白质结构中的α-螺旋随着脆化时间增加而减少,β-折叠随着脆化时间增加而增加,无规则卷曲在脆化初期变化较大,脆化后期变化不明显。其次,采用SG、SNV、MSC和Normalize这4种方法预处理拉曼光谱数据,发现Normalize的预处理效果最好,预测集RMSEP为2.33,R²P为0.73。再次,采用PLSR、SVR和BPNN方法建立脆肉草鱼脆度与拉曼光谱信息关系模型,预测集RMSEP分别为2.33、2.26和1.96,R²P分别为0.73、0.78和0.83,其中BPNN预测模型效果最好。研究表明,采用拉曼光谱技术和Normalize-BPNN建立的预测模型可以检测脆肉草鱼脆度。本研究将为脆肉草鱼脆度检测提供新的思路。     

Changes in enzymatic and structural properties of grass carp fast skeletal myosin induced by the laboratory-conditioned thermal acclimation and seasonal acclimatization

ABSTRACT:   Myosins were prepared from fast skeletal muscles of grass carp thermally acclimated to 10, 20 and 30°C in the laboratory as well as from those seasonally acclimatized and collected in January (winter) 2003 and May (spring), August (summer) and November (autumn) 2002. The maximal initial velocities ( V _max) of actin-activated Mg²⁺-ATPase activity for myosins from the 10°C-acclimated and winter grass carp were 1.7–1.8-fold as high as those from the 30°C-acclimated and summer fish. The inactivation rate constant ( K _D) of Ca²⁺-ATPase for myosin from the 10°C-acclimated grass carp was three to fourfold higher than those for myosins from the fish acclimated to 20°C and 30°C, whereas myosin from winter grass carp was about sevenfold as high as that for myosin from summer fish. Myosins from spring and autumn fish showed K _D values comparable to those of the fish acclimated to 30°C and 10°C, respectively. In differential scanning calorimetry analysis, the transition temperature ( T _m) was observed near 38°C and 45–46°C with most myosins. However, the lowest T _m at 32–33°C was given as one of the major endotherms in myosins from the 10°C-acclimated, autumn and winter fish. These responses of grass carp to changed environmental temperatures were almost similar to those for common carp reported previously.     

嘉庚蛸精子发生的超微结构

在研究GCL细胞中EROD催化底物反应时间的基础上分别以三种数学模型拟合，分析比较了诱导剂TCDD、PCB、PB、BaP、3-MC、BNF对GCL细胞EROD酶活的剂量．效应曲线，结果表明Log-Normal模型能较好的拟合药酶诱导前升后降的钟形效应曲线，所得方程参数值p100和EC100可用于药物代谢酶的诱导研究；Gentox模型拟合度相对较低且其EC50值显著高于半效应浓度；Logistic模型只能拟合曲线诱导上升部分而且嬲50和P100与Log-Normal模型相比显著偏高。进一步研究结果显示诱导剂TCDD对GCL细胞作用时间越长，EC100越大，P100越小，但在作用48h后即达到较大诱导效应，延长时间并无显著加强作用。     

草鱼摄食后肝胰脏组织淀粉酶活性的变化

用含量均为45％的马铃薯淀粉、糊精、葡萄糖和45％马铃薯淀粉 0．5％Cr2O3为碳水化合物源的4种试验饲料饲喂草鱼，50d后测定消化组织的淀粉酶活性。结果表明，各试验组消化组织的淀粉酶活性在摄食后下降，肝胰脏、前肠、中肠、后肠淀粉酶活性的最低值分别出现在摄食后3h、3h、3—5h、5—8h，并且淀粉 Cr2O3组的淀粉酶活性低于淀粉组。     

鲫、草鱼外周血中淋巴细胞和单核细胞对鲤血管内皮细胞的粘附

借鉴哺乳动物内皮细胞体外培养技术，结合鱼类细胞自身特点，纯化培养鲤血管内皮细胞并传至3代，以此作为粘附材料。应用淋巴细胞分离液离心技术并结合玻璃粘附法分离纯化鲫、草鱼外周血中淋巴细胞、单核细胞，并与上述3代内皮细胞进行免疫粘附试验，同时进行免疫粘附动力学观察。结果显示，鲫、草鱼两类细胞对内皮细胞的粘附率分别为0.09±0.013，0.20±0.018；0.11±0.015，0.21±0.023。表明鲤科鱼类不同种的同类细胞粘附率差异不大，而同种不同类细胞则差异显著。动力学观察分析表明，淋巴细胞粘附较快，60min进入平台期；单核细胞粘附慢，120min进入平台期。初步证明鱼类内皮细胞具有免疫介导作用。     

Qualitative and quantitative strategies of thermal adaptation of grass carp (Ctenopharyngodon idella) cytoplasmic malate dehydrogenases

Malate dehydrogenase isozymes of grass carp,Ctenopharyngodon idella, were identified by mitochondrial preparation and thermal denaturation. The structural and kinetic characteristics of chromatographically separated thermostable and thermolabile cMDHs were different in (1) half-life at 42°C, 10 min and 24 h, respectively, (2) optimal substrate, oxaloacetate and malate, concentrations, and (3) the apparent Michaelis-Menten constants of NADH and oxaloacetate.Total MDH activity in white muscle of 11°C-acclimated fish was about twice that of the 30°C-acclimated group. In addition, the ratio of the thermostable to thermolabile cMDH activity in white muscle of 30°C-acclimated fish was significantly higher than that of 11°C-acclimated fish. These results suggest that temperature acclimation can induce temperature compensation in MDH activity and differential expression of thermostable and thermolabile cMDH isozymes in freshwater fish.     

草鱼出血病细胞培养灭活疫苗的研究——疫苗株的免疫原性及其有效免疫剂量的比较

本文比较了疫苗株FR—854和FR—836—w的免疫原性,及其对三寸左右草鱼种的有效免疫剂量。疫苗株FR—854和FR—836—w均有较强的免疫原性,其保护力可达70%以上。但试验结果初步证明,FR—854疫苗比FR—836—w疫苗免疫原性更强。经统计分析,FR—854疫苗的免疫保护力可达88.9±12.0（6）%,血清中和抗体效价为160.5±58.9（6）;而FR-838-W疫苗分别只有71.3±14.2（6）%、88.3±26.2（6）;二者有显著的差异（0.05>P>0.01）。注射免疫三寸左右的草鱼种,FR—854的免疫剂量在3—5×10^4.5TCID0/尾左右,FR—836—w在3—5×107.5TCID₅₀/尾左右,其免疫保护力可达80%左右,同时我们测得ER—854的半数免疫量为10^5.1TCID₅₀/ml。     

三江源区高寒草地牧草产量主要影响因子分析

利用高寒草地多年牧草产量和主要气象因子,运用主成分法分析了影响牧草产量的影响因子,并用逐步回归分析法建立了牧草产量回归统计模型,结果表明,影响牧草产量的因子顺序为:7月份温度x4＞4月降水x8＞8月日照x19＞6月日照x17＞生长期总降水量x13＞7月降水x11.结合通径分析方法对影响因子进行分析,对牧草产量的直接作用...     

Effects of Competition upon the Productivity of White Clover-Perennial Ryegrass Mixtures. Analysis of and Interrelations between Characters

A diallel crossing programme amongst tour contrasting white clover varieties was used to generate material for studying the interrelationships amongst those characters which affect the productivity of white clover- perennial ryegrass mixtures under a cutting-only management regime. Such a regime favoured clover growth. All the clover characters exhibited strong positive correlations with mixture yield. However, this combination of clover characters did not promote growth of the grass companion. For this a low growing variety with a dense stolon network appeared preferable. Path analysis indicated that differences existed between the two companion grass varieties used for this experiment in their upon clover characters.     

A vernalization protocol for obtaining progenies from regenerated and transgenic tall fescue plants

Tall fescue is an important outcrossing forage and turf grass species that requires vernalization to flower. A reproducible protocol was developed for vernalization of regenerated, transgenic and seed‐derived tall fescue plants. Following the vernalization scheme that involved gradual changes of temperature and daylength, seeds were routinely produced from vernalized plants under greenhouse conditions. Molecular analyses of progenies obtained from crosses between transgenic and seed‐derived plants revealed stable meiotic transmission of transgenes following Mendelian inheritance in transgenic tall fescue.