Role of Weight History on Functional Limitations and Disability in Late Adulthood: The ARIC Study

Objective: To examine associations of weight history with functional limitations and disability in white and African‐American men and women. Research Methods and Procedures: Data were from the Atherosclerosis Risk in Communities study (n = 11, 177). Associations of recalled weight status at age 25 and weight change from age 25 to ages 45 to 64 with functional limitations, activities of daily living (ADLs), and instrumental activities of daily living (IADLs) at follow‐up (ages 52 to 75) were examined using logistic regression. Results: Obesity (BMI ≥ 30 kg/m²) at age 25 was associated with functional limitations and ADL and IADL impairment at follow‐up in white and African‐American men and women. For example, obese compared with normal weight (BMI, 18.5 to 24.9 kg/m²) white women had higher odds of mild [odds ratio (95% confidence interval), 1.97 (1.18 to 3.29)] and severe [9.81 (5.92 to 16.27)] functional limitations and ADL [3.48 (2.36 to 5.13)] and IADL [2.95 (2.00 to 4.33)] impairment. In African‐American women, obesity was associated with higher odds of mild [2.71 (1.14 to 6.41)] and severe [6.01 (2.53 to 14.26)] functional limitations and ADL [1.82 (1.10 to 3.00)] and IADL [2.39 (1.47 to 3.90)] impairment. Similar associations were found in men. Compared with weight maintenance (±10 lbs), large weight gain (>30 lbs) from age 25 to ages 45 to 64 was also associated with functional limitations and ADL and IADL impairment in white and African‐American men and women. Discussion: Maintenance of a healthy body weight throughout adulthood may play a role in preventing or delaying the onset of functional limitations and disability, resulting in increased quality of life and decreased health care costs.     

饲料中添加外源酶对大黄鱼和鲈氮磷排泄的影响

本研究以大黄鱼和鲈为实验对象,探讨饲料中添加植酸酶(PY)和非淀粉性多糖酶(WX和VP)对其氨氮和可溶性磷(PO3-4-P)排泄的影响.以含植物蛋白的饲料为基础饲料,分别向每千克饲料中添加200mg植酸酶(酶的活性为2500IU/g)、 800mg WX(主要包括葡聚糖酶、戊聚糖酶和纤维素酶,各种酶的活性皆为50IU/g)、 400mg VP(主要为木聚糖酶,酶的活性为1000IU/g)以及800mg WX 400mg VP配制出5种实验饲料.实验鱼在海水网箱中经过8周的摄食驯养后,转入室内水族箱中进行氮磷排泄测定实验.在水族箱中经2天的适应后,测定饥饿状态下氨氮及可溶性磷的排泄率.然后饱食投喂,并连续测定摄食后48h内鱼体氨氮和可溶性磷的排泄率.实验期间水温为26.5-32.5℃,盐度为32.5‰-36‰,溶氧在7 mg/L以上.实验结果表明,饥饿状态下实验鱼的氨氮和可溶性磷排泄不受实验饲料影响(p>0.05).而在饱食条件下,实验饲料中添加非淀粉性多糖酶(WX、VP及WX VP)显著降低了实验鱼的氨氮排泄率(p<0.05),而添加植酸酶组实验鱼的氨氮排泄率与对照组差异不显著.饲料处理对实验鱼可溶性磷的排泄率的影响不显著(p>0.05),但添加植酸酶组实验鱼的可溶性磷排泄率有增加的趋势.     

灰胸竹鸡消化系统形态解剖初探

观察和测定了13只灰胸竹鸡消化系统的解剖参数,结果表明:雌性和雄性体重分别为227.39 g和216.79 g,体长分别为237.22 mm和230.00 mm;腺胃粘膜表面具有40～50枚圆形乳头,肌胃较发达;雌性和雄性的食道分别长约93.96 mm和99.75 mm,肠道总长分别为683.83 mm和672.95 mm,肝脏分别重4.87 g和5.20 g,胰脏分别重0.38 g和0.45 g.此研究为进行竹鸡的人工驯养和生物学研究提供解剖学资料.     

Optimal moult strategies in migratory birds

Avian migration, which involves billions of birds flying vast distances, is known to influence all aspects of avian life. Here we investigate how birds fit moult into an annual cycle determined by the need to migrate. Large variation exists in moulting patterns in relation to migration: for instance, moult can occur after breeding in the summer or after arrival in the wintering quarters. Here we use an optimal annual routine model to investigate why this variation exists. The modelled bird's decisions depend on the time of year, its energy reserves, breeding status, experience, flight feather quality and location. Our results suggest that the temporal and spatial variations in food are an important influence on a migratory bird's annual cycle. Summer moult occurs when food has a high peak on the breeding site in the summer, but it is less seasonal elsewhere. Winter moult occurs if there is a short period of high food availability in summer and a strong winter peak at different locations (i.e. the food is very seasonal but in opposite phase on these areas). This finding might explain why only long-distance migrants have a winter moult.     

Optimal annual routines: behaviour in the context of physiology and ecology

Organisms in a seasonal environment often schedule activities in a regular way over the year. If we assume that such annual routines have been shaped by natural selection then life-history theory should provide a basis for explaining them. We argue that many life-history trade-offs are mediated by underlying physiological variables that act on various time scales. The dynamics of these variables often preclude considering one period of the year in isolation. In order to capture the essence of annual routines, and many life-history traits, a detailed model of changes in physiological state over the annual cycle is required. We outline a modelling approach based on suitable physiological and ecological state variables that can capture this underlying biology, and describe how models based on this approach can be used to generate a range of insights and predictions.     

Major quantitative trait loci affect resistance to infectious pancreatic necrosis in Atlantic salmon (Salmo salar)

Infectious pancreatic necrosis (IPN) is a viral disease currently presenting a major problem in the production of Atlantic salmon (Salmon salar). IPN can cause significant mortality to salmon fry within freshwater hatcheries and to smolts following transfer to seawater, although challenged populations show clear genetic variation in resistance. To determine whether this genetic variation includes loci of major effect, a genomewide quantitative trait loci (QTL) scan was performed within 10 full-sib families that had received a natural seawater IPN challenge. To utilize the large difference between Atlantic salmon male and female recombination rates, a two-stage mapping strategy was employed. Initially, a sire-based QTL analysis was used to detect linkage groups with significant effects on IPN resistance, using two to three microsatellite markers per linkage group. A dam-based analysis with additional markers was then used to confirm and position any detected QTL. Two genomewide significant QTL and one suggestive QTL were detected in the genome scan. The most significant QTL was mapped to linkage group 21 and was significant at the genomewide level in both the sire and the dam-based analyses. The identified QTL can be applied in marker-assisted selection programs to improve the resistance of salmon to IPN and reduce disease-related mortality.     

分子伴侣GroE系统能量传递机制的研究

用SwissPDBViewer软件对分子伴侣GroE系统与底物的相互作用进行了模拟 ,结果表明 :GroEL顶端结构域在GroES和靶蛋白结合之后发生了明显的变化 ;GroEL的cis环上有与三磷酸腺苷ATP相结合的位点 ,ATP水解之后形成的ADP与活性中心的残基相结合 ,而这种结合除导致残基Thr30的构型发生了变化之外 ,其它残基的空间位置和构型基本保持不变 ,暗示其它残基在能量传递过程中形成了刚性骨架 ,而与ADP分子磷酸键结合的残基Thr30则是能量传递的力点。