Comparative sensitivities of electrophoretic assays for human enzymes

The sensitivities of 26 starch gel electrophoretic enzyme assays have been compared using HeLa human cells and A9 mouse cells grown in vitro.This research was supported by National Institutes of Health Grant No. USPHS GM 09966.     

大车前与平车前营养器官的比较解剖学研究

利用光学显微镜和石蜡切片技术对生长在盐碱地的大车前和平车前的营养器官进行了比较解剖学研究。结果表明二者的解剖结构存在差异:平车前根的木栓层较大车前的狭窄,栓内层细胞层数较少;平车前叶表皮的细胞角质膜较薄,孔下室较小,构成维管束鞘的薄壁细胞较大车前小,束鞘细胞两层。二者都具有适应盐渍环境的结构特征:营养器官中通气组织发达;根结构中薄壁组织和木栓发达;叶表皮角质层发达。     

The Influences of Environment, Mating Habitat, and Predation on Evolution of Pinniped Lactation Strategies

Seals have adapted their social systems and lactation strategies to marine environments that include open and ice-covered oceans, high and low productivity, extremes in seasonality, and ocean- and terrestrial-type predators. Different explanations for the variation in pinniped lactation systems have been proposed but tests of alternative hypotheses have not sufficiently accounted for phylogeny and body size. After controlling for this variation, I predicted that environment, mating habitat, and predation would yield a fuller explanation. Lactation traits, duration, pup growth rate, and fat content were significantly influenced by both body size and phylogeny, which together explained 20–69% of the variation. After controlling for this variation, initial results did not support the environment hypothesis, as no differences in lactation traits were found between species living in polar (≥60°N) versus equatorial (<60°N) environments. In contrast, seals that nurse in areas of Arctic sea ice contending with ice-hunting predators, such as polar bears, had relatively short lactation compared to species living in the Antarctic and more equatorial regions. Also, the availability of predator-free islands for terrestrial mating and parturition was related to a harem mating system, increased sexual size dimorphism (SSD), and slow juvenile growth rates, less fat in milk, and longer lactation. Using structural equation modeling, latitude and size of harems provided independent explanations for all three lactation traits. Thus, use of islands in ice-free waters, predation in Arctic ice-covered waters, and more milk fat in high-latitude seals together provided adequate explanations for the evolution of lactation diversity among pinnipeds.     

Development and ossification of the feeding apparatus in the larvae of two co‐occurring species of kob (Sciaenidae), Argyrosomus japonicus and Argyrosomus inodorus,in South Africa

The teeth of the oral jaws of two sympatric species of Argyrosomus, Argyrosomus japonicus and Argyrosomus inodorus, found along the South African coast developed first on the premaxilla and then on the dentary of the lower jaw. Teeth were observed on the premaxilla of A. inodorus [head length (L_H) = 1·0 mm; notochord length (L_N) = 2·7 mm] at a smaller size than in A. japonicus (L_H = 1·2 mm; L_N = 4·7 mm). The ventral elements of the gill arches (hypo‐ and basibranchials) were not ossified by the end of preflexion. The fifth ceratobranchial began ossifying and possessed pharyngeal teeth by 1·2 mm L_H (L_N = 4·7 mm) in A. japonicus and 1·1 mm L_H (L_N = 3·2 mm) in A. inodorus. To complement the osteological data, stomach contents were also analysed as a proxy for feeding apparatus functionality. Prey were first present in the stomach of A. japonicus at 1·2 mm L_H (L_N = 4·7 mm) and only 22% of the stomachs contained no prey suggesting that A. japonicus is already actively foraging by preflexion. In comparison, 83% of the stomachs of A. inodorus contained no prey and a single prey item was present in the largest examined specimen (L_H = 1·6 mm; L_N = 5·4 mm). Elements of the feeding apparatus begin to ossify early during ontogeny. While the overall pattern of ossification is similar between the two species, A. japonicus may be able to begin feeding at smaller head lengths relative to A. inodorus in their nursery habitats.     

Range edges and the molecular divergence of Greya moth populations

Aim We investigated the geographical pattern of genetic divergence and demographic history in the prodoxid moth Greya obscura throughout its entire geographical range in far western North America and compared it to the geographical patterns found in a previously studied species, Greya politella, which co‐occurs over the same range, in the same habitats, and on the same host plants. Location The study included sites distributed throughout the California Floristic Province. Methods We used analysis of cytochrome c oxidase subunit I (COI) and amplified fragment length polymorphisms to evaluate the pattern and history of genetic continuity among populations. Results Greya obscura populations show a history of spatial expansion with considerable haplotype diversity in the centre of the geographical range. As with G. politella, some range‐edge populations of G. obscura are sufficiently divergent (6.7% in COI) to be considered as potentially cryptic species. Greya obscura and G. politella, however, differ in the specific range‐edge sites showing greatest genetic divergence and cryptic speciation. Main conclusions These results corroborate the view that range edges are important cradles of divergence and speciation. In addition, the results indicate that the geographical pattern of divergence at edges may differ even among closely related species occupying the same habitats and using the same hosts.     

Early ontogeny of a South Pacific gonostomatid fish <Emphasis Type="Italic">Sigmops longipinnis</Emphasis>

 During the R/V Hakuho-maru Cruise KH-95-2, Ocean Research Institute, University of Tokyo, from Tokyo, Japan to the South Pacific east of Australia (22° N–30° S; 126° E–176° E) from June to September, 1995, 77 unidentified gonostomatid larvae (5.5–20.0 mm SL) were collected south of 20° S with an IKMT net. They subsequently were identified as Sigmops longipinnis (Mukhacheva), and its ontogeny during the latter part of the larval stage (body form and proportions, photophores, pigmentation, and meristics) is described here. The larvae develop a species-specific row of melanophores along the midlateral line anterior to the caudal peduncle and another along the middorsal line from before the dorsal fin to just before the caudal fin. Received: June 24, 2002 / Revised: November 2, 2002 / Accepted: January 31, 2003     

High air humidity is sufficient for successful egg incubation and early post‐embryonic development in the marbled crayfish (Procambarus virginalis)

相似文献   

Comparative bioacoustics: a roadmap for quantifying and comparing animal sounds across diverse taxa

Animals produce a wide array of sounds with highly variable acoustic structures. It is possible to understand the causes and consequences of this variation across taxa with phylogenetic comparative analyses. Acoustic and evolutionary analyses are rapidly increasing in sophistication such that choosing appropriate acoustic and evolutionary approaches is increasingly difficult. However, the correct choice of analysis can have profound effects on output and evolutionary inferences. Here, we identify and address some of the challenges for this growing field by providing a roadmap for quantifying and comparing sound in a phylogenetic context for researchers with a broad range of scientific backgrounds. Sound, as a continuous, multidimensional trait can be particularly challenging to measure because it can be hard to identify variables that can be compared across taxa and it is also no small feat to process and analyse the resulting high-dimensional acoustic data using approaches that are appropriate for subsequent evolutionary analysis. Additionally, terminological inconsistencies and the role of learning in the development of acoustic traits need to be considered. Phylogenetic comparative analyses also have their own sets of caveats to consider. We provide a set of recommendations for delimiting acoustic signals into discrete, comparable acoustic units. We also present a three-stage workflow for extracting relevant acoustic data, including options for multivariate analyses and dimensionality reduction that is compatible with phylogenetic comparative analysis. We then summarize available phylogenetic comparative approaches and how they have been used in comparative bioacoustics, and address the limitations of comparative analyses with behavioural data. Lastly, we recommend how to apply these methods to acoustic data across a range of study systems. In this way, we provide an integrated framework to aid in quantitative analysis of cross-taxa variation in animal sounds for comparative phylogenetic analysis. In addition, we advocate the standardization of acoustic terminology across disciplines and taxa, adoption of automated methods for acoustic feature extraction, and establishment of strong data archival practices for acoustic recordings and data analyses. Combining such practices with our proposed workflow will greatly advance the reproducibility, biological interpretation, and longevity of comparative bioacoustic studies.     

De novo MECP2 duplication derived from paternal germ line result in dysmorphism and developmental delay

Xq28 duplications encompassing the methyl CpG binding protein 2 (MECP2) in males exhibit a distinct phenotype, including developmental delay, facial dysmorphism, muscular hypotonia, intellectual disability, poor or absent speech, recurrent infections and early death. The vast majority of affected males inherit the MECP2 duplication from their usually asymptomatic carrier mothers. Only a few cases with Xq28 duplication originating from de novo unbalanced X/Y translocation have been reported and the paternal origin of the aberration has only been validated in three males in the related literature. Here we present a karyotypically normal male with features characteristic of the MECP2 duplication syndrome. The genome-wide SNP genotyping shows a de novo 2.26-Mb duplication from Xq28 to the terminus. The genotypes of the SNPs within the duplicated region indicated a paternal origin. Furthermore, the results of fluorescence in situ hybridization (FISH) indicated a novel Xq:Yp translocation, characterized as der(Y)t(Y;X)(p11.32;q28), which suggests an aberrant that occurred during spermatogenesis. The phenotype is compared to the previously reported cases with Xq28 duplication originated from an unbalanced X/Y translocation, and there was no specific part of the phenotype that could be contributed to the origin of parental imbalances. This report further highlights the capacity of high-molecular cytogenetic methods, such as SNP array and FISH, in the identification of submicroscopic rearrangement, structural configuration and parental origin of aberrant while in the evaluation of children with idiopathic developmental delay and intellectual disability.     

Discriminating the effects of phylogenetic hypothesis,tree resolution and clade age estimates on phylogenetic signal measurements

Understanding how species traits evolved over time is the central question to comprehend assembly rules that govern the phylogenetic structure of communities. The measurement of phylogenetic signal (PS) in ecologically relevant traits is a first step to understand phylogenetically structured community patterns. The different methods available to estimate PS make it difficult to choose which is most appropriate. Furthermore, alternative phylogenetic tree hypotheses, node resolution and clade age estimates might influence PS measurements. In this study, we evaluated to what extent these parameters affect different methods of PS analysis, and discuss advantages and disadvantages when selecting which method to use. We measured fruit/seed traits and flowering/fruiting phenology of endozoochoric species occurring in Southern Brazilian Araucaria forests and evaluated their PS using Mantel regressions, phylogenetic eigenvector regressions (PVR) and K statistic. Mantel regressions always gave less significant results compared to PVR and K statistic in all combinations of phylogenetic trees constructed. Moreover, a better phylogenetic resolution affected PS, independently of the method used to estimate it. Morphological seed traits tended to show higher PS than diaspores traits, while PS in flowering/fruiting phenology depended mostly on the method used to estimate it. This study demonstrates that different PS estimates are obtained depending on the chosen method and the phylogenetic tree resolution. This finding has implications for inferences on phylogenetic niche conservatism or ecological processes determining phylogenetic community structure.