饲喂频率对鲈鱼生长及体生化成分的影响

选取同一种饵料设置1次·d-1、2次·d-1、3次·d-1、4次·d-14个饲喂频率,采用静水连续充气养殖系统,在盐度为26.0%～27.0%、温度为26～30℃条件下对鲈鱼(85.95±2.04)g进行为期40d的生长实验.结果表明:(1)饲喂频率影响鲈鱼的生长是由食物转化率和摄食率的提高共同引起的.(2)水分含量随饲喂频率的增高而保持不变;蛋白质含量随饲喂频率的增加,基本保持不变;脂肪含量随饲喂频率的增高而明显减少;灰分含量随饲喂频率的增多而明显增加.(3)鲈鱼的适宜饲喂频率为2次·d-1.     

从一个例子看统计分析在辅助医学诊断中的有用之处

从讨论影响脂肪肝的主要因素排序出发,应用简明统计分析,给出了辅助医学诊断中用于判断患者患脂肪肝的可能性,由此,对于可能性为零的情形可以排除进一步的生化检查,也就不会发生相应的感染.     

一类生化反应微分方程的定性分析

对一类生化反应模型x=δ-ax-xpyq,y=xpyq-by(δ>0,b>0,a>0,p 1,q>1)进行了研究.讨论了系统平衡点的稳定性态,对系统极限环的位置做出了估计.同时讨论了系统无环的充分条件以及极限环存在惟一性条件.     

Mechanisms of structure formation in particulate gels of β-lactoglobulin formed near the isoelectric point

Particulate gels are known to be formed by bovine β-lactoglobulin near the isoelectric point when partial unfolding is allowed to occur under heating. The aggregation process of the protein has been investigated within the context of a nucleation and growth process by preparing gels under precisely controlled thermal histories. This was achieved using a Differential Scanning Calorimeter (DSC) to provide controlled heating rates, and known final temperatures and incubation times. The resulting particulate gels were characterized by their particle size and polydispersity using Environmental Scanning Electron Microscopy (ESEM), which permits hydrated samples to be observed. Particle size was found to decrease with increasing final temperature, with the aggregation taking longer to reach completion for lower temperatures. Particle size was also found to decrease with increasing heating rate. This system could be modelled as evolving via nucleation and growth by taking into account the fact that the concentration of the aggregating species was varying as a function of temperature as well as time. The intrinsic tryptophan fluorescence as a function of temperature was used as a guide to the fraction of unfolded protein in solution, thereby permitting successful comparisons between the model predictions and the particle sizes to be made.-1     

微藻脂肪合成与代谢调控

随着能源与环境问题的日益严峻,利用微藻生产生物柴油已经成为研究者们关注的焦点。与传统油料作物相比,微藻具有生长速度快、含油量高、不占用耕地等优势,是极具潜力的生物燃料生产原料。虽然许多微藻在压力条件下会在细胞内积累脂肪,特别是中性脂肪三酰甘油(TAG),它是生产生物柴油的主要原料,但目前对于微藻脂肪的合成和代谢调控还了解的很少。为了更好地理解和操纵微藻脂肪代谢以增强脂肪积累,本文综述了微藻脂肪合成与代谢调控的研究进展,包括TAG生物合成途径,提高脂肪积累的生化调控和基因工程策略,阐述了营养控制对脂肪积累的影响,总结了增强脂肪酸合成途径、增强Kennedy途径、调控TAG旁路途经、抑制脂肪合成的竞争途径、抑制脂肪的分解代谢等5种基因工程策略,同时也对微藻脂肪代谢研究的发展进行了展望。