Leg impairment magnifies reproductive costs in male Mediterranean fruit flies,Ceratitis capitata

Injuries frequently accumulate with age in nature. Despite the commonality of injury and the resulting impairment, there are limited experimental data for the effects of impairment on life history trade‐offs between reproduction and survival in insects. We tested the effects of artificial injury and the resulting impairment on the reproductive costs and behavior of male medflies, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae). Treatment flies were impaired by amputating tarsomere segments 2–5 from the right foreleg at either eclosion or age 22 days. The effect of impairment and age on the cost of reproduction was tested by varying the timing of female availability among the treatments. Courtship behavior and copulation rates were observed hourly from age 2–5 days to determine the effects of impairment on reproductive behavior. Female access combined with the impairment reduced the life expectancy of males more than the impairment alone, whereas the health effect of amputation was influenced by age. Conversely, the risk of death due to impairment was not influenced by the males' mating status prior to amputation. The males' copulation success was reduced due to impairment, whereas courtship behavior was not affected. Impairment does not reduce the males' impulse to mate, but decreases the females' receptivity to copulation, while also increasing the cost of each successful mating. Overall, minor impairment lowers the reproductive success of males and reduces longevity.     

Differences in NMR Spectra between Some α- and γ-Glutamyl Dipeptides

A methanol-utilizing phototrophic bacterium, strain M402, was isolated from surface water of an acidic hot spring. The isolated strain was identified as Rhodopseudomonas acidophila from its morphological and physiological characters. Profiles of the utilization of non-aromatic compounds as carbon sources by this strain were in good agreement with those of some strains of R. acidophila reported by Pfennig [J. Bacteriol., 99, 597 (1969)]. However, strain M402 was found to be capable of utilizing vanillic acid, vanillin, vanillyl alcohol, ferulic acid, veratric acid, syringic acid, syringal-dehyde and benzyl alcohol as carbon sources under anaerobic-light conditions. Although Pfennig did not refer to these abilities of his strains, these notable characters of strain M402 seem to be additional new characters of R. acidophila.     

10种梅花品种及其3种近缘种的核型分析

采用压片法,对10种梅花品种及其3种近缘种杏、山杏和紫叶李进行了核型分析。结果表明:10种梅花品种及杏、山杏和紫叶李均为二倍体2n=2x=16,核不对称系数为55.17%~61.71%,核型类型有1A、1B、2B等3种类型,所有品种或种的核型都由其中部或近中部的着丝点染色体组成。‘丰后’和‘俏美人’等2个杂种品种染色体信息介于梅花与杏、山杏和紫叶李之间。     

Deriving how far structural information is transmitted through parallel homodimeric coiled‐coils: A correlation analysis of helical staggers

How local conformation is affected by local sequence is fairly well understood for alpha‐helical coiled‐coils, but less is known about how local conformation is influenced by distant features. Here, I describe an approach to detect such an effect, based on computing correlation coefficients of local out‐of‐register alignments, or so‐called “staggers” between the helices, as a function of the axial distance between the staggers. This approach requires parallel homodimers, in which each stagger can occur with two “signs,” where either one helix or the other is shifted towards the N terminus. The signs of such staggers separated by up to 12 residues are strongly correlated, indicating that the conformations of the ends of coiled‐coils are commonly influenced by attached structures. Thus, the structures of coiled‐coil residues aberrantly attached to alternative proteins, such as those resulting from leukemogenic chromosomal rearrangements, may be distinguishable from those in normal tissues, and in turn serve as targets of selective drug design. The signs of helical staggers separated by between 13 and 30 residues are moderately yet significantly correlated, indicating that some of the coiled‐coils transmit this conformational feature axially for at least 45 Å. A positive, albeit noisy, correlation also exists among tropomyosin coiled‐coils for signed staggers separated by the 40‐residue actin repeat distance, consistent with the semi‐flexible tropomyosin filament binding F‐actin and regulating skeletal muscle contraction in a partially cooperative manner. Communication of the signs of axial staggers is explained in part by minimization of main‐chain hydrogen bond deformations. © Proteins 2013. © 2012 Wiley Periodicals, Inc.     

补光对越冬灰仓鼠体重、主要器官指数及精子数量的影响

目的研究补光对灰仓鼠(Cricetulus migratorus)越冬时脏器器官的影响。方法室温下将其分为自然光照组和补充光照组,分别在第0、30、48和150天时测定动物的体重和脏器器官的重量,应用涂片法检查精子的数量。结果自然光照时,精子数量在冬至时变化不大,但冬至后第18天,灰仓鼠的睾丸系数降到最低值,精子数量仅为422枚,第150天时恢复到正常繁殖状态,精子数量达到7440枚。其他脏器指数在冬至时最高,第150天时最低。补充光照后,雌雄鼠体重高峰值时间均比自然光照组提前100 d,各器官指数变化与体重变化情况相类似,但睾丸和子宫系数维持稳定,精子数量未发现减少。结论在自然光照时越冬灰仓鼠的脏器指数逐渐下降,第150天时脏器指数达至最高值,睾丸指数在冬至后第18天下降到最低值,处于非繁殖状态。补充光照后,越冬灰仓鼠的精子数量和子宫指数变化不大,一直维持繁殖状态。     

SD大鼠主要脏器间的相关性分析

目的测定成年SD大鼠体重与各脏器重量,并对不同脏器之间及体重与各脏器重量的相关性进行分析。方法选用三月龄SD大鼠雄性共24只,进行人道处死,解剖后分别测定心、肝、肺、肾等脏器重量,并作相关性分析。结果 SD大鼠的心、肝、肺、脾、肾与胃空体的相关性分析中,SD大鼠的心脏及肝脏重量之间不相关(P>0.05),且分别与其他各脏器及胃空体之间也无明显相关(P>0.05);而脾脏的重量与肾脏重量之间则相关极为显著(P<0.01);胃空体与肺、脾呈现极显著相关(P<0.01),与肾脏呈显著相关(P<0.05)。结论通过解剖比较SD大鼠各脏器之间的关系,对动物体内各脏器的大小及相互关系有了初步的认知,为今后进行的动物相关实验研究打下基础。     

Theoretical study of the intermolecular potential energy and second virial coefficient in the mixtures of CH4 and Kr gases: a comparison with experimental data

The intermolecular potential energy surface (IPS) in the mixtures of CH₄–Kr gases from ab initio calculations has been explored. The ab initio calculation was performed at the second-order Møller–Plesset perturbation theory (MP₂), with the 6-311+G(2df,2pd) basis set, for three relative orientations of two CH₄–Kr molecules as a function of CH₄–Kr separation distance. In this work, the IPS, U(r), of the CH₄–Kr complex has been investigated, where the vertex (V), edge (E) and face (F) of CH₄ approaches to Kr have been considered. Then, adjustable parameters of the Lennard-Jones and Buckingham potential energy function are fitted to the ab initio MP2/6-311+G(2df,2pd) interaction energies for three different orientations. Assuming a given set of parameters, we theoretically obtained second virial coefficients for the CH₄–Kr system, and compared with the experimental data at different temperatures. Trivial differences can be observed between the experimental and computational results.     

Self-Diffusion in Electrostatically Stabilized Colloidal Suspensions Using Brownian Dynamics

Abstract

Brownian dynamics is applied to suspended colloidal particles interacting through a screened Coulombic pair potential in the dilute region where the hydrodynamics is approximated by Stokes drag. Calculated properties include the osmotic pressure, the radial distribution function, and the self-diffusion coefficient. Verification is obtained by comparing the results to independently evaluated properties. Self-diffusion coefficicents are compared to approximate theories in the literature. The self-diffusion coefficient is observed to depend strongly on the local structure but only slightly on the longer range structure.     

Molecular dynamics simulation of diffusion of hydrogen in binary hydrogen–tetrahydrofuran hydrate

The binary structure II hydrogen–tetrahydrofuran (THF) hydrate was studied with molecular dynamics simulation. The simulations were carried out at 300, 310 K and 10.1 MPa, and with various contents of hydrogen and THF. The migrations of hydrogen molecules from cage to cage were observed. The migration process of hydrogen was also analysed, and the diffusion coefficients of hydrogen in the hydrate were calculated. The calculated diffusion coefficients qualitatively agreed with the experimental data. Double and quintet occupancies of hydrogen molecules were observed in the small and large cages, respectively, without changing the hydrate structure.