变色树蜥骨骼系统的解剖

用透明骨骼标本染色法制作变色树蜥的骨骼标本,并对其骨骼系统进行了全面的描述.其骨骼可分为中轴骨骼(包括头骨、脊柱、胸骨、肋骨)和附肢骨骼(包括肩带、腰带、前肢骨、后肢骨).其头骨呈梨形,眼眶完整.颈椎8枚,胸椎4枚,腰椎11枚,荐椎2枚,尾椎多于34枚.有颈肋4对,胸肋4对,腰肋11对.表现出了一系列进化特征,如前颌骨愈合成1块,额骨也愈合成1块,颧骨消失,鳞骨变小,犁骨薄弱,下颌夹板骨与齿骨、冠状骨及隅骨之间的骨缝不明显,愈合程度较高.     

荒漠麻蜥骨骼系统的解剖及与相近科属蜥蜴骨骼特征比较

采用透明骨骼染色法,观测了荒漠麻蜥Eremias przewaskii比较完整的骨骼系统,对其各部分骨骼组成、形态和位置作了详细的描述,为麻蜥属的分类及演化提供骨骼方面的基础资料。其骨骼可分为中轴骨骼(包括头骨、脊柱、胸骨和肋骨)和附肢骨骼(包括肩带、腰带、前肢骨和后肢骨)。其头骨呈三角形,眼窝与颞窝相通,不完整。颈椎8枚,胸椎5枚,腰椎13枚,荐椎2枚,尾椎44～45枚。与已报道的蜥蜴物种骨骼特征相比较,发现其前肢腕骨部位、尺骨和桡骨远端中间具1枚骨化不完全的籽骨——介间骨;在前肢腕骨与掌骨的腹面,有2块平面不规整四方形的掌籽骨,位于连接腕骨与各掌骨的韧带中间;在后肢股骨远端的关节内侧与髌骨相对的位置存在1粒籽骨,为股腓侧豆状骨;跗骨腹面下方有1枚三角形籽骨——跗籽骨。     

Necessity of an adequate nerve supply for regeneration of the amputated pectoral fin in the teleost Fundulus

The present work deals with determination of the threshold of nerve fibers per unit of amputation surface necessary for regeneration of the pectoral fins of a teleost, Fundulus. Partial denervation of the amputated pectoral fins, i.e., resection of one or two of the three nerves of the brachial (=pectoral) plexus revealed that the presence of a single one allows the amputated fin to regenerate. From these data and others obtained previously, it is concluded that the nervous requirements for a teleost fin to regenerate are similar or slightly lower than those for tetrapods, for example in the newt, which are capable of appendage regeneration.     

Duplication and divergence of fgf8 functions in teleost development and evolution

Fibroblast growth factors play critical roles in many aspects of embryo patterning that are conserved across broad phylogenetic distances. To help understand the evolution of fibroblast growth factor functions, we identified members of the Fgf8/17/18-subfamily in the three-spine stickleback Gasterosteus aculeatus, and investigated their evolutionary relationships and expression patterns. We found that fgf17b is the ortholog of tetrapod Fgf17, whereas the teleost genes called fgf8 and fgf17a are duplicates of the tetrapod gene Fgf8, and thus should be called fgf8a and fgf8b. Phylogenetic analysis supports the view that the Fgf8/17/18-subfamily expanded during the ray-fin fish genome duplication. In situ hybridization experiments showed that stickleback fgf8 duplicates exhibited common and unique expression patterns, indicating that tissue specialization followed the gene duplication event. Moreover, direct comparison of stickleback and zebrafish embryonic expression patterns of fgf8 co-orthologs suggested lineage-specific independent subfunction partitioning and the acquisition or the loss of ortholog functions. In tetrapods, Fgf8 plays an important role in the apical ectodermal ridge of the developing pectoral appendage. Surprisingly, differences in the expression of fgf8a in the apical ectodermal ridge of the pectoral fin bud in zebrafish and stickleback, coupled with the role of fgf16 and fgf24 in teleost pectoral appendage show that different Fgf genes may play similar roles in limb development in various vertebrates.     

Further Electron Microscope Characterization of Spore Appendages of Clostridium bifermentans

Two distinct spore appendage types of Clostridium bifermentans, a pinlike appendage and a tubular appendage, were studied by electron microscopy. The pinlike appendage is characterized by a shaft, about 100 A in diameter, which has a lobed caplike structure. The tubular appendage, 500 to 600 A in diameter, is characterized by a hirsute region consisting of small filaments or fibrils. Gross morphology and ultrastructural features of both types are described.     

Highly homologous filamin polypeptides have different distributions in avian slow and fast muscle fibers

The high molecular weight actin-binding protein filamin is located at the periphery of the Z disk in the fast adult chicken pectoral muscle (Gomer, R. H., and E. Lazarides, 1981, Cell, 23: 524-532). In contrast, we have found that in the slow anterior latissimus dorsi (ALD) muscle, filamin was additionally located throughout the l band as judged by immunofluorescence with affinity-purified antibodies on myofibrils and cryosections. The Z line proteins desmin and alpha-actinin, however, had the same distribution in ALD as they do in pectoral muscle. Quantitation of filamin and actin from the two muscle types showed that there was approximately 10 times as much filamin per actin in ALD myofibrils as in pectoral myofibrils. Filamin immunoprecipitated from ALD had an electrophoretic mobility in SDS polyacrylamide gels identical to that of pectoral myofibril filamin and slightly greater than that of chicken gizzard filamin. Two-dimensional peptide maps of filamin immunoprecipitated and labeled with 125I showed that ALD myofibril filamin was virtually identical to pectoral myofibril filamin and was distinct from chicken gizzard filamin.     

Appendages of Clostridium bifermentans Spores

Four distinct spore appendage types were detected in an electron microscope survey of 12 strains of Clostridium bifermentans. A smooth tubular appendage and a feather-like appendage are described in detail. In addition, hirsute tubular appendages and small pin-like appendages are depicted. Spores of four strains apparently lack appendages.     

广西早泥盆世一新型胴甲鱼化石并初步探讨其系统分类位置

本文描述的胴甲鱼化石标本,采自广西象州大乐早泥盆世地层.化石系内、外模,但保存非常完整,包括自然连接的头部、躯干、胸鳍及躯甲后的尾部.头甲、躯甲的特征较为接近星鳞鱼 (Asterolepis) 的特征,而某些特征又与云南鱼 (Yunnanolepis) 类似.胸鳍分为近节和远节,鳍片排列近似欧洲的翼甲鱼 (Pterichthyodes) 型的胸鳍.根据头甲、躯甲及胸鳍的特征,笔者建立了一新属、新种——Liujiangolepis suni gen. et sp. nov.,代表胴甲鱼类中—新科——Liujiangolepidae fam. nov..文中对新属种的胸鳍结构和新属种在胴甲鱼类中的分类位置做了初步探讨.     

Ultrastructure of the antennal sensorial appendage of larvae of Ophonus ardosiacus (Lutshnik, 1922) (Coleoptera, Carabidae) and possible correlations between size and shape and the larval feeding habits

The antennal sensory appendage morphology was studied in 19 species of carabid beetle larvae using scanning electron microscopy. Shape and size of the organ has been re-examined in selected taxa and are compared to figure out possible correlations between antennal sensory structures and larval morphoecological types. Morphometric analysis shows no correlation between antennal sensory appendage dimension and the four most common behavioural types. The ultrastructure of this sensory organ is described for larvae of Ophonus ardosiacus and the possible function is discussed. Olfactory function has been indicated as the most probable. The high number of chemosensory neurons of this multiporous organ suggests a possible ability of fine odour discrimination related to prey choice or host location.     

Life in the flow lane: differences in pectoral fin morphology suggest transitions in station-holding demand across species of marine sculpin

Aquatic organisms exposed to high flow regimes typically exhibit adaptations to decrease overall drag and increase friction with the substrate. However, these adaptations have not yet been examined on a structural level. Sculpins (Scorpaeniformes: Cottoidea) have regionalized pectoral fins that are modified for increasing friction with the substrate, and morphological specialization varies across species. We examined body and pectoral fin morphology of 9 species to determine patterns of body and pectoral fin specialization. Intact specimens and pectoral fins were measured, and multivariate techniques determined the differences among species. Cluster analysis identified 4 groups that likely represent differences in station-holding demand, and this was supported by a discriminant function analysis. Primarily, the high-demand group had increased peduncle depth (specialization for acceleration) and larger pectoral fins with less webbed ventral rays (specialization for mechanical gripping) compared to other groups; secondarily, the high-demand group had a greater aspect ratio and a reduced number of pectoral fin rays (specialization for lift generation) than other groups. The function of sculpin pectoral fins likely shifts from primarily gripping where demand is likely low, to an equal dependence on gripping and negative lift generation where demand is likely high. Specialization of the ventral pectoral fin region for gripping likely contributes to the recent diversification of some species into high-demand habitats.     

Morphological and histochemical characterization of the pectoral fin muscle of batoids

Batoids differ from other elasmobranch fishes in that they possess dorsoventrally flattened bodies with enlarged muscled pectoral fins. Most batoids also swim using either of two modes of locomotion: undulation or oscillation of the pectoral fins. In other elasmobranchs (e.g., sharks), the main locomotory muscle is located in the axial myotome; in contrast, the main locomotory muscle in batoids is found in the enlarged pectoral fins. The pectoral fin muscles of sharks have a simple structure, confined to the base of the fin; however, little to no data are available on the more complex musculature within the pectoral fins of batoids. Understanding the types of fibers and their arrangement within the pectoral fins may elucidate how batoid fishes are able to utilize such unique swimming modes. In the present study, histochemical methods including succinate dehydrogenase (SDH) and immunofluoresence were used to determine the different fiber types comprising these muscles in three batoid species: Atlantic stingray (Dasyatis sabina), ocellate river stingray (Potamotrygon motoro) and cownose ray (Rhinoptera bonasus). All three species had muscles comprised of two muscle fiber types (slow-red and fast-white). The undulatory species, D. sabina and P. motoro, had a larger proportion of fast-white muscle fibers compared to the oscillatory species, R. bonasus. The muscle fiber sizes were similar between each species, though generally smaller compared to the axial musculature in other elasmobranch fishes. These results suggest that batoid locomotion can be distinguished using muscle fiber type proportions. Undulatory species are more benthic with fast-white fibers allowing them to contract their muscles quickly, as a possible means of escape from potential predators. Oscillatory species are pelagic and are known to migrate long distances with muscles using slow-red fibers to aid in sustained swimming.     

Developmentally regulated lectin in embryonic chick muscle and a myogenic cell line.

Soluble extracts of embryonic chick pectoral muscle and myoblast clone L6 agglutinated trypsin treated glutaraldehyde fixed rabbit erythrocytes. Agglutination activity was blocked by thiodigalactoside, lactose and related saccharides but not by many other saccharides. Agglutination activity of chick pectoral muscle extracts increased at least one order of magnitude between 8 and 16 days of chick embryo development, as the pectoral muscle differentiated. With L6 myoblasts there was a three-fold increase in activity of the extracts as the myoblasts fused to form multinucleated myotubes.     

Comparative morphology of the pectoral fin spine of the Persian sturgeon Acipenser persicus,the Russian sturgeon Acipenser gueldenstaedtii,and the Starry sturgeon Acipenser stellatus in Iranian waters of the Caspian Sea

The morphological characteristics of the pectoral fin spine were compared in three species of sturgeon, the Persian sturgeon (Acipenser persicus), the Russian sturgeon (Acipenser gueldenstaedtii), and the Starry sturgeon (Acipenser stellatus), all sampled from the Caspian Sea. On the basis of morphological characters of the pectoral fin spine, 62.2% of the individuals were correctly classified into separate groups. The cluster analysis also divided the three species into two major subgroups. Acipenser persicus and A. gueldenstaedtii were grouped together, suggesting a similar evolutionary basis. Significant morphological heterogeneity in pectoral fin spine characteristics was observed among the three sturgeon species. Principal component analysis identified the largest differences were in the pectoral fin spine size and the angle between distal pectoral fin spine and the horizontal line (A°). The first and second principal components (PC1 and PC2) of all observations accounted for 64.19% and 14.33% of the total variation, respectively. The combination of all analyses showed the relevance of applying pectoral fin spine shape for interspecific distinction of the three species of sturgeons.     

A new species of <Emphasis Type="Italic">Discostroma</Emphasis> and its anamorph <Emphasis Type="Italic">Seimatosporium</Emphasis> with two morphological types of conidia,isolated from the stems of <Emphasis Type="Italic">Paeonia suffruticosa</Emphasis>

Conidia of two morphologically different types, one with a basal appendage only and the other with appendage at both ends, were isolated from the stems of Paeonia suffruticosa. Single conidial isolates of both types of conidia yield identical colonies, which then produced both types of conidia on agar media depending on temperature, thus showing that both types of conidia belong to the same fungus. Seimatosporium botan is described based on its morphological characteristics. The teleomorph of the fungus was first found on sterilized P. suffruticosa stems placed on water agar, when grown at 5°C for 2 months in 12-h photoperiod. Discostroma botan is described for this fungus. The teleomorph is also found on the same host in the field.     

The ontogeny of Aeschynanthus seeds – a comparative study using scanning electron microscopy

Seed morphology in the genus Aeschynanthus (Gesneriaceae) is important in sectional classification. The number and type of appendages at the hilar end of the seed, papilla structure and testa cell orientation are all significant. SEM studies of seed and appendage development, at seven-day intervals from pre-pollination to maturity, were carried out in order to investigate possible sectional and seed type relationships. Fifteen species, representing six sections, were examined. Results show that there are no significant differences pre-pollination but two patterns were evident post-pollination, for both seed and hilar appendage development. Pattern I occurred in sects Microtrichium and Haplotrichium s.s . Pattern II was seen in sects. Aeschynanthus , Diplotrichium and Polytrichium . Patterns were less clear in species belonging to a group not yet circumscribed and here referred to as sect. X , but most closely resembled Pattern II. This study shows that the orientation of the testa cells is a developmental feature, defining the two major clades in the genus. It also shows that, in the two sections possessing more than one hilar appendage, there is initial development of one appendage relative to the coma in sect. Polytrichium and of one appendage relative to the second in sect. Diplotrichium . The results of this study are discussed with respect to molecular and morphological findings, and the evolutionary significance considered. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 138 , 197–207.     

Ecomorphological correlates in ten species of subtropical seagrass fishes: diet and microhabitat utilization

Synopsis Ecomorphological correlates were sought among ten species of distantly related subtropical seagrass fishes. Morphometric data associated with feeding and microhabitat utilization were compared by principal components analysis, cluster analysis, and canonical correspondence analysis to dietary data. Morphology was generally a poor predictor of diet except for a group of mid-water planktotrophic filter feeders. Separation of the species along morphological axes appears to be related more to microhabitat utilization resulting in three major groups: (1) a group of planktotrophic, mid-water fishes specialized for cruising and seeking out evasive prey characterized by a compressed fusiform body, forked caudal fin, long, closely spaced gill rakers, short to intermediate! length pectoral fin, pointed pectoral fin, large lateral eye, short head, and a terminal or subterminal mouth; (2) slow swimming, less maneuverable epibenthic fishes that pick or suck their prey off the substrate. They are united by more rounded caudal and pectoral fins, and short or no gill rakers; and (3) a group of more mobile and maneuverable epibenthic foragers characterized by a more compressed, sub-gibbose body, long, pointed pectoral fins, forked caudal fins, large lateral eyes, subterminal mouth, and greater jaw protrusibility. Cases of convergence in trophic and microhabitat utilization characters were apparent in some of the groups.     

An improved technique for estimating pectoral muscle protein condition from body measurements of live gulls

Body measurements, which could be taken from live birds, were used to estimate total pectoral muscle protein in Lesser Black-backed Gulls Larus fuscus. The maximum cross-sectional area of the flight muscles was measured from the profile of the muscle surface over the keel, and this was used in conjunction with the length of the flight muscle to estimate muscle volume. The estimate of muscle volume was then used with fresh body weight to estimate total flight muscle protein. A highly significant correlation was found between the estimated values and actual pectoral muscle protein mass determined by carcass analysis. The model developed from the source group was then validated using a second independent sample, in which flight muscle protein was estimated from the model. Carcass analysis again demonstrated a good correlation between estimated and actual total protein. Different methods of controlling for body-size to calculate protein condition from measures of total protein were considered. The technique described here provides a simple and reliable method of estimating pectoral muscle protein condition in live gulls which could be applied to studies of body condition in other species.     

Sexually dimorphic fin regeneration in zebrafish controlled by androgen/GSK3 signaling

Certain fish and amphibians regenerate entire fins and limbs after amputation, whereas such potential is absent in birds and limited in mammals to digit tips [1, 2]. Additionally, regenerative success can change during life stages. Anuran tadpoles gradually lose the capacity to regenerate limbs [3,?4], and digit regeneration occurs more effectively in fetal mice and human children than adults [5-8]. Little is known about mechanisms that control regenerative capacity. Here, we identify an unexpected difference between male and female zebrafish in the regenerative potential of a major appendage. Males display regenerative defects in amputated pectoral fins, caused by impaired blastemal proliferation. This regenerative failure emerges after sexual maturity, is mimicked in androgen-treated females, and is suppressed in males by androgen receptor antagonism. Androgen signaling maintains expression of dkk1b and igfbp2a, which encode secreted inhibitors of Wnt and Igf signaling, respectively. Furthermore, the regulatory target of Wnts and Igfs, GSK3β, is inefficiently inactivated in male fin regenerates compared with females. Pharmacological inhibition of GSK3 in males increases blastemal proliferation and restores regenerative pattern. Our findings identify a natural sex bias in appendage regenerative capacity and indicate an underlying regulatory circuit in which androgen locally restricts key morphogenetic programs after amputation.