核糖体转录间隔子2应用于鱼类种属的鉴别

为了防止珍稀鱼类的非法捕捞和销售, 鱼类种属的鉴别就成为非常关键的问题, 特别是形态学方法无法区分的样品(如鱼苗、鱼鳞、鱼卵、鱼肉及其加工产品等)。为了帮助珍稀鱼类资源的管理和保护, 文章报道了一种利用核糖体基因的转录间隔子2鉴别鱼类种属的分子遗传学方法: (1) 利用同一目鱼类5.8S rRNA和28S rRNA基因的保守性, 设计出扩增鲤形目鱼类这两个基因间转录间隔子2 DNA片段, 测序获得它们的碱基排列顺序; (2) 再根据不同鱼类转录间隔子2序列的差异, 设计出每种鱼的种属特异引物、种属鉴别标准物, 构建鱼类分子分类图谱, 利用PCR复合扩增技术鉴别鱼类种属。通过对国内不同地方采集的5种鲤形目鱼类的210个单一品种样本和40个混合样本的鉴别检验, 该方法能够准确、灵敏和快速鉴别这5种鱼, 可用于鱼类资源保护和评估、管理和开发, 特别是在渔业管理人员渔业执法、海关打击珍稀鱼类走私、防止商业欺诈和外来有害生物入侵等方面非常有用     

The effect of wai tan kung on autonomic nervous modulation in the elderly

The decline in physical capacity in the elderly can be ameliorated by low-velocity, low-impact exercises. Wai tan kung (WTK), a traditional Taiwanese conditioning exercise, is suitable for older people. This study evaluated the effect of WTK on autonomic nervous modulation in the elderly. Twenty WTK practitioners and 20 normal controls were recruited in this study. The stationary state spectral heart rate variability (HRV) measures, hemodynamics, and spirometry between the WTK group and normal controls and sequential changes in HRV measures and hemodynamics after WTK were compared. We found that the standard deviation and coefficient of variation of RR intervals, total power, low frequency power (LFP), and normalized LFP (nLFP) in WTK practitioners before WTK were all significantly higher than those of normal controls. After WTK, the normalized high-frequency power increased (nHFP) significantly from 27.7±13.2 normalized units (nu) before WTK to 37.6±16.0 nu 30 min after WTK, and to 39.8±20.1 nu 60 min after WTK. In contrast, LFP/HFP decreased significantly from 1.3±1.0 before WTK to 1.0±0.9 30 min after WTK and to 0.8±0.6 60 min after WTK. We concluded that in the short term, WTK enhances vagal modulation and suppresses sympathetic modulation, whereas in the long term, WTK enhances sympathetic modulation without compromising vagal modulation of the elderly. Thus WTK is good health-promoting calisthenics that can be recommended to the elderly.