Elemental and biochemical composition of<Emphasis Type="Italic"> Nephrops norvegicus</Emphasis> (Linnaeus 1758) larvae from the Mediterranean and Irish Seas

The Norway lobster, Nephrops norvegicus, is a commercially exploited decapod which is widely distributed throughout the north-eastern Atlantic and the Mediterranean Sea. Ovigerous females originating from the Mediterranean and the Irish Seas were held in the laboratory until larvae hatched. Biomass and biochemical composition, as well as digestive gland structure, were examined in newly hatched larvae from these two regions. In addition, previously published data from a North Sea population were included in our comparison. Elemental analyses showed that the absolute quantities of dry mass (DM), carbon (C), nitrogen (N) and hydrogen (H) (collectively referred to as CHN) per individual, and the C:N mass ratios, were significantly lower, while the relative CHN, protein and lipid values (in % of DM) were higher in samples from the Irish Sea compared to larvae originating from either the Mediterranean or the North Sea. As in CHN, the absolute level of protein per individual was higher in larvae from the Mediterranean, while no significant differences were observed in the individual lipid contents. Likewise, the digestive gland structure at hatching did not show any differences between study areas. Intraspecific variability in biomass and chemical composition of newly hatched larvae from different regions may be related to differential patterns of reproduction in regions with different climatic conditions. Lobster larvae hatch in the Mediterranean Sea predominantly in winter when both water temperature and planktonic food availability are at a minimum, while hatching in the Irish Sea occurs under more favourable conditions in spring. Hence, significantly higher wet mass, dry mass and protein values in Mediterranean larvae may represent adaptive traits allowing for early posthatching survival and development under food-limited conditions in an oligotrophic environment.Communicated by H.-D. Franke     

Temporal and spatial genetic structure in Vitellaria paradoxa (shea tree) in an agroforestry system in southern Mali

Ten microsatellite loci were used to investigate the impact of human activity on the spatial and temporal genetic structure of Vitellaria paradoxa (Sapotaceae), a parkland tree species in agroforestry systems in southern Mali. Two stands (forest and fallow) and three cohorts (adults, juveniles and natural regeneration) in each stand were studied to: (i) compare their levels of genetic diversity (gene diversity, HE; allelic richness, Rs; and inbreeding, FIS); (ii) assess their genetic differentiation (FST); and (iii) compare their levels of spatial genetic structuring. Gene diversity parameters did not vary substantially among stands or cohorts, and tests for bottleneck events were nonsignificant. The inbreeding coefficients were not significantly different from zero in most cases (FIS = -0.025 in forest and 0.045 in fallow), suggesting that the species is probably outbreeding. There was a weak decrease in F(IS) with age, suggesting inbreeding depression. Differentiation of stands within each cohort was weak (FST = 0.026, 0.0005, 0.010 for adults, juveniles and regeneration, respectively), suggesting extensive gene flow. Cohorts within each stand were little differentiated (FST = -0.001 and 0.001 in forest and fallow, respectively). The spatial genetic structure was more pronounced in fallow than in forest where adults showed no spatial structuring. In conclusion, despite the huge influence of human activity on the life cycle of Vitellaria paradoxa growing in parkland systems, the impact on the pattern of genetic variation at microsatellite loci appears rather limited, possibly due to the buffering effect of extensive gene flow between unmanaged and managed populations.     

Analysis of part of the<Emphasis Type="Italic">Trichophyton rubrum</Emphasis> ESTs

Trichophyton rubrum (T. rubrum) is the most common of the superficial fungi. In an effort to better understand the genetic and biochemical makeup ofT. rubrum, we generated cDNA libraries from 3 growth stages and used these to isolate 4002 unique expressed sequence tags (ESTs). Sequence comparisons with the Genbank database allowed 1226 of the ESTs to be assigned putative functions or matched with homologs from other organisms. Of the remaining ESTs, 989 were only weakly similar to known sequences and 1787 had no identifiable functions, suggesting that they represent novel genes. We further analyzed the presence of several important genes involved in the growth, metabolism, signal transduction, pathogenesis and drug resistance inT. rubrum. This information was used to newly elucidate important metabolic pathways inT. rubrum. Taken together, our results should form the molecular basis for continued research on the physiological processes and pathogenic mechanisms ofT. rubrum, and may lead to a better understanding of fungal drug resistance and identification of new drug targets.     

Effects of plant traits on ecosystem and regional processes: a conceptual framework for predicting the consequences of global change

Human activities are causing widespread changes in the species composition of natural and managed ecosystems, but the consequences of these changes are poorly understood. This paper presents a conceptual framework for predicting the ecosystem and regional consequences of changes in plant species composition. Changes in species composition have greatest ecological effects when they modify the ecological factors that directly control (and respond to) ecosystem processes. These interactive controls include: functional types of organisms present in the ecosystem; soil resources used by organisms to grow and reproduce; modulators such as microclimate that influence the activity of organisms; disturbance regime; and human activities. Plant traits related to size and growth rate are particularly important because they determine the productive capacity of vegetation and the rates of decomposition and nitrogen mineralization. Because the same plant traits affect most key processes in the cycling of carbon and nutrients, changes in plant traits tend to affect most biogeochemical cycling processes in parallel. Plant traits also have landscape and regional effects through their effects on water and energy exchange and disturbance regime.     

Microscopic anatomy of the orbital Harderian gland in the common tree shrew (Tupaia glis)

The orbital Harderian gland of the common tree shrew (Tupaia glis) was investigated at the macroscopic and microscopic levels. In the glands of both sexes only one acinar cell type was found. The cell is characterized by the presence of numerous lipid vacuoles of variable size and by a small number of PAS-positive, electron-dense granules distributed throughout the cytoplasm, which are predominant at the basal portion of each acinar cell. The duct system is well developed within the gland. The content of lipid vacuoles within the acinar cells is secreted from the apical portions by exocytosis, indicating the exocrine function of the organ. Apart from the lipid vacuoles, both acinar and ductal luminal contents of the Harderian gland also contain accretion of electron-dense materials. The vascularization within the Harderian gland is unique in that two capillary types (small fenestrated and irregular sinusoidal capillaries) could be demonstrated. The presence of fenestrated capillaries together with other morphological features (such as accumulation of the small electron-dense granules at the basal pole and the presence of basolateral microvilli) near the basal portion of the acinar cells suggest that the Harderian gland in T. glis might also be involved in an endocrine function.     

Differential mesowear in occluding upper and lower molars: opening mesowear analysis for lower molars and premolars in hypsodont horses

A new approach of reconstructing ungulate diet, the mesowear method, was recently introduced by Fortelius and Solounias ([2000] Am Mus Novitat 3301:1-36). Mesowear is based on facet development on the occlusal surfaces of the teeth. Restricting mesowear investigation to maxillary cheek teeth would allow mesowear investigation only in assemblages of large numbers of individuals and therefore would generally restrict this method to relatively few assemblages of recent and fossil ungulates. Most of the fossil, subfossil, and recent ungulate osteological assemblages that may be assigned to a single taxon have smaller numbers of individuals. This results in a demand to extend the mesowear method to further tooth positions in order to obtain stable dietary classifications of fossil taxa. The focus of this article is to test if a consistent mesowear classification is obtainable for mandibular as well as for maxillary teeth. For statistical testing, large assemblages of isolated cheek teeth of the Vallesian hipparionine horse Hippotherium primigenium and of the recent zebra Equus burchelli were employed as models. The upper tooth positions P4, M1, M2, and M3 as suggested by Kaiser and Solounias (2003) as the model for the "extended" mesowear method and the lower tooth positions P4-M3 were tested for their consistency in classification of the mesowear variables. We found a considerable shift of the mesowear signature towards the grazing edge of the mesowear continuum in lower cheek teeth. In order to adjust the signal of lower teeth to the signal of the upper teeth, a calibration factor was introduced which allowed incorporation of lower cheek teeth into the same model of mesowear investigation together with upper cheek teeth. We propose that this model is particularly suited for the reconstruction of paleodiets in hypsodont hipparionine and equine equids. We further investigated the functional relation between the mesowear profiles and the distribution of dental tissues along the course of the occlusal contact. We therefore correlated mesowear profiles with enamel distribution profiles and found the mesowear profile to be strongly controlled by the attritional environment encountered by a given apex area. The differential signal observed in cusp apex morphology between upper and lower cheek teeth was found to be more closely related to attrition by the antagonistic tooth than to the distribution of dental tissues in the tooth under consideration. The results suggest a general extension of the mesowear method of paleodiet reconstruction and a basic scenario for the evolution of anisodont dentitions.     

Functional-adaptive anatomy of the axial skeleton of some extant marsupials and the paleobiology of the paleocene marsupials Mayulestes ferox and Pucadelphys andinus

In this study, the axial skeletons of two Early Paleocene marsupials, Mayulestes ferox and Pucadelphys andinus, were analyzed functionally and compared to that of six South American and three Australian species of extant marsupials. In the case of the South American opossums, myological data of the epaxial musculature were collected and analyzed and osteological-myological associations were related to locomotor behavior. Various features of the vertebral column that relate to diet or to locomotor or postural patterns were pointed out. These features include: the craniocaudal development of the neural process of the axis; the position of the anticlinal vertebra; the morphology of the neural processes of the thoracolumbar vertebrae (orientation, length, and craniocaudal width); the length, orientation, and curvature of the transverse processes of the lumbar vertebrae; and the length and robustness of the caudal vertebrae. In both fossil forms the vertebral column is mobile and allows a great range of flexion and extension of the spine, more so than in most of the living didelphids. It is emphasized here that the analysis of the axial skeleton complements and improves the conclusions provided by the forelimb and hindlimb analyses. It is proposed that Mayulestes and Pucadelphys represent an ancestral morphotype suggesting that the generalized type of locomotion of Paleocene marsupials was partly terrestrial with some climbing ability.     

Efficient identification of side-chain patterns using a multidimensional index tree

Convergent evolution often produces similar functional sites in nonhomologous proteins. The identification of these sites can make it possible to infer function from structure, to pinpoint the location of a functional site, to identify enzymes with similar enzymatic mechanisms, or to discover putative functional sites. In this article, a novel method is presented that (a) queries a database of protein structures for the occurrence of a given side chain pattern and (b) identifies interesting side-chain patterns in a given structure. For efficiency and to make a robust statistical evaluation of the significance of a similarity possible, patterns of three residues (or triads) are considered. Each triad is encoded as a high-dimensional vector and stored in an SR (Sphere/Rectangle) tree, an efficient multidimensional index tree. Identifying similar triads can then be reformulated as identifying neighboring vectors. The method deals with many features that otherwise complicate the identification of meaningful patterns: shifted backbone positions, conservative substitutions, various atom label ambiguities and mirror imaged geometries. The combined treatment of these features leads to the identification of previously unidentified patterns. In particular, the identification of mirror imaged side-chain patterns is unique to the here-described method. Interesting triads in a given structure can be identified by extracting all triads and comparing them with a database of triads involved in ligand binding. The approach was tested by an all-against-all comparison of unique representatives of all SCOP superfamilies. New findings include mirror imaged metal binding and active sites, and a putative active site in bacterial luciferase.     

两种陀螺藻囊壳的微细结构和元素组成分析

利用从自然界水体中采集到的标本为材料,对2种陀螺藻的囊壳的微细结构和元素组成进行分析比较,结果表明：组成陀螺藻囊壳的主要矿质元素是硅(Si)、铁(Fe)和铝(A1),并含有少量的镁(Mg)、锌(Zn)、钙(Ca)等元素。囊壳的表面形态是不规则的,不宜作为分类依据。     

甘薯品种营养成份与抗小象虫的相关性研究

通过田间和网室测定结果,抗小象虫较好的甘薯品种有抗虫1号、台农26、Tis2534、Ricin和鸡蛋黄;抗小象虫较弱的品种有新种花、惠红早、“329”、广薯15等。甘薯品种的营养成份与抗小象虫相关性分析结果表明,抗、感品种与粗纤维、粗脂肪含量无明显相关,与粗淀粉有显负相关,R1=-0．9935,而与粗蛋白和18种氨基酸总量有显正相关,R2=0．9741,R3=0．9621。表现粗淀粉含量高的品种,其虫害指敦较低,抗虫性强;而粗蛋白含量和18种氨基酸总量高的品种,其虫害指数较高,抗虫性则表现较弱。测定分析说明了甘薯品种营养成份与抗虫性存在一定的相关性。