不同的下丘脑肽和神经递质对鲤鱼促性腺激素和生长激素分泌活动的影响

以１龄性腺发育中期鲤鱼为材料,采用腹腔（ｉ．ｐ）注射的方法,研究不同的下丘脑肽和神经递质对鲤鱼促性腺激素（ＧｔＨ）和生长激素（ＧＨ）分泌的影响。结果表明：促甲状腺激素释放激素（ＴＲＨ）、Ｌ－多巴（Ｌ－ＤＯＰＡ）、甲基睾酮（ＭＴ）、γ－氨基丁酸（ＧＡＢＡ）、促黄体素释放激素类似物（ＬＨＲＨ－Ａ）和三碘甲状腺原氨酸（Ｔ３）都能显著刺激ＧｔＨ的分泌,但最大效应时间各不相同。ＴＲＨ和ＬＨＲＨ－Ａ能促进ＧＨ的分泌,Ｌ－ＤＯＰＡ、ＭＴ、ＧＡＢＡ对血清ＧＨ水平没有明显影响;Ｔ３则对ＧＨ分泌有一定的抑制作用。这说明鲤鱼ＧｔＨ和ＧＨ的分泌除了受各自的下丘脑释放因子和释放抑制因子的双重神经内分泌调控外,还受多种其它相同和不同调节因子的影响,也反映了鲤鱼ＧｔＨ和ＧＨ分泌的神经内分泌调控的复杂性。     

PHYLOGENETIC ANALYSIS OF PHENOTYPIC COVARIANCE STRUCTURE. I. CONTRASTING RESULTS FROM MATRIX CORRELATION AND COMMON PRINCIPAL COMPONENT ANALYSES

Applications of quantitative techniques to understanding macroevolutionary patterns typically assume that genetic variances and covariances remain constant. That assumption is tested among 28 populations of the Phyllotis darwini species group (leaf-eared mice). Phenotypic covariances are used as a surrogate for genetic covariances to allow much greater phylogenetic sampling. Two new approaches are applied that extend the comparative method to multivariate data. The efficacy of these techniques are compared, and their sensitivity to sampling error examined. Pairwise matrix correlations of correlation matrices are consistently very high (> 0.90) and show no significant association between matrix similarity and phylogenetic relatedness. Hierarchical decomposition of common principal component (CPC) analyses applied to each clade in the phylogeny rejects the hypothesis that common principal component structure is shared in clades more inclusive than subspecies. Most subspecies also lack a common covariance structure as described by the CPC model. The hypothesis of constant covariances must be rejected, but the magnitudes of divergence in covariance structure appear to be small. Matrix correlations are very sensitive to sampling error, while CPC is not. CPC is a powerful statistical tool that allows detailed testing of underlying patterns of covariation.     

Absolute hearing thresholds and critical masking ratios in the European barn owl: a comparison with other owls

Absolute thresholds and critical masking ratios were determined behaviorally for the European barn owl (Tyto alba guttata). It shows an excellent sensitivity throughout its hearing range with a minimum threshold of −14.2 dB sound pressure level at 6.3 kHz, which is similar to the sensitivity found in the American barn owl (Tyto alba pratincola) and some other owls. Both the European and the American barn owl have a high upper-frequency limit of hearing exceeding that in other bird species. Critical masking ratios, that can provide an estimate for the frequency selectivity in the barn owl's hearing system, were determined with a noise of about 0 dB spectrum level. They increased from 19.1 dB at 2 kHz to 29.2 dB at 8 kHz at a rate of 5.1 dB per octave. The corresponding critical ratio bandwidths were 81, 218, 562 and 831 Hz for test-tone frequencies of 2, 4, 6.3 and 8 kHz, respectively. These values indicate, contrary to expectations based on the spatial representation of frequencies on the basilar papilla, increasing bandwidths of auditory filters in the region of the barn owl's auditory fovea. This increase, however, correlates with the increase in the bandwidths of tuning curves in the barn owl's auditory fovea. Accepted: 27 November 1997     

Unraveling the efficiency of RAPD and SSR markers in diversity analysis and population structure estimation in common bean

Increase in food production viz-a-viz quality of food is important to feed the growing human population to attain food as well as nutritional security. The availability of diverse germplasm of any crop is an important genetic resource to mine the genes that may assist in attaining food as well as nutritional security. Here we used 15 RAPD and 23 SSR markers to elucidate diversity among 51 common bean genotypes mostly landraces collected from the Himalayan region of Jammu and Kashmir, India. We observed that both the markers are highly polymorphic. The discriminatory power of these markers was determined using various parameters like; percent polymorphism, PIC, resolving power and marker index. 15 RAPDs produced 171 polymorphic bands, while 23 SSRs produced 268 polymorphic bands. SSRs showed a higher PIC value (0.300) compared to RAPDs (0.243). Further the resolving power of SSRs was 5.241 compared to 3.86 for RAPDs. However, RAPDs showed a higher marker index (2.69) compared to SSRs (1.279) that may be attributed to their higher multiplex ratio. The dendrograms generated with hierarchical UPGMA cluster analysis grouped genotypes into two main clusters with various degrees of sub clustering within the cluster. Here we observed that both the marker systems showed comparable accuracy in grouping genotypes of common bean according to their area of cultivation. The model based STRUCTURE analysis using 15 RAPD and 23 SSR markers identified a population with 3 sub-populations which corresponds to distance based groupings. High level of genetic diversity was observed within the population. These findings have further implications in common bean breeding as well as conservation programs.     

Diet of the Omani Owl,Strix butleri,near Nakhal,Oman

The diet of the Omani Owl, Strix butleri, was studied for the first time based on re- cently collected pellets. A total of 22 individual prey items represented three mam- mals (all rodents), at least two undetermined gecko species and one scorpion. By fre- quency, Acomys cahirinus constituted 31.8% and lizards 27.3%, while Gerbillus nanus and G. dasyurus were the least consumed prey items (4.5% each).     

Diet of a nesting pair of Long-eared Owls,Asio otus,in an urban environment in southwestern Turkey (Aves: Strigidae)

Pellets were collected under an active Long-eared Owl (Asio otus) nest in the city centre of Denizli, Turkey. The nest was located in a conifer tree in a 5.7 ha urban park, centrally-located in the city of Denizli, with a human population of 577,000 people. During April-June 2014, a total of 64 pellets containing remains of 86 individual prey items was found. All prey were Passeriformes and consisted of two species belonging to Passeridae and Hirundinidae. 78 of the 86 prey items (90.7%) were House Sparrow (Passer domesticus) and the other eight (9.3%) were House Martin (Delichon urbicum). This is one of the first studies to indicate that the Long-eared Owl's nesting season diet consists entirely of birds. The main factor affecting this result is probably the fact that the owls live in an urbanised setting.     

棕色田鼠与甘肃鼢鼠咀嚼肌结构和功能的比较

为了解棕色田鼠与甘肃鼢鼠对食物的适应机制, 对它们的咀嚼肌及相关的骨学特征做了比较解剖, 并运用生物力学原理分析下颌运动方式及食物加工过程的咀嚼效率。结果表明, 两个种的下颌的咀嚼均以水平面的前后向运动为主, 研磨加工植物纤维。相应地, 咀嚼肌、牙齿及相关的骨骼形态也具有一系列与此运动方式和功能相适应的结构特征, 如彼此平行的左右侧颊齿列、沟槽状的下颌关节窝以及咬肌的排列位置前移等。此外, 两个种具有几乎相同的门齿切割效率和臼齿咀嚼效率。两个种的上述相似特征与它们有着相似的食物结构是一致的。     

Characterization of Genome and Chromosomes in Octoploid Wheat wheatgrass Amphiploid Zhong 2 Using Fluorescence in situ Hybridization and Chromosome Pairing Analysis

Genomic constitution of octoploid wheat-wheatgrass amphiploid Zhong 2 was analyzed by chromosome pairing and fluorescence in sim hybridization techniques. The results indicated that the octoploid wheatwheatgrass chromosomes in Zhong 2 were derived from the distant homologous genomes of wheatgrass ( Agropyron intermedium (Host) P.B. = Elytrigia intermedia (Host) Nevski = Thinotopyrum intermedium (Host) Barkworth and Dewey, and thew distant homologous genomes were not from the E geaome of T. elongatum 2x. Zhong 2 contained 12 wheatgrass chromosomes in which a pair of chromosomes was involved in translocation between wheatgrass and wheat chromosomes.