杞麓湖鲤鱼鳞片表面结构的扫描电镜观察

采用扫描电镜技术对鲤科鱼类鳞片表面结构进行观察研究,目前国内尚未见报道。本工作主要以杞麓湖的鲤鱼为研究对象,同时观察了鲤亚科其他属鱼类的鳞片表面结构,发现鳞纹上的齿状粒突可能是从无到有,同时探察此结构有无可能作为分类的一项指标。鉴于杞麓鲤的鳞纹上具齿状粒突,而华南鲤则无,再综合考虑二者骨骼性状的差异,作者认为,这些性状可作为将杞麓鲤由普通鲤的一个亚种提升为一个独立种级地位的证据。从鳞片辐射沟的亚显微结构推测,辐射沟具有两方面的功能,一方面可对鳞片的热胀冷缩起缓冲作用:另一方面可增强鳞片的柔软弯曲性。     

多齿蛇鲻鳞片表面结构的扫描电镜观察

本文对多齿蛇鲻鳞片表面结构进行扫描电镜观祭,描述了鳞纹、年轮形式、齿状粒突、辐射沟、伸缩缝、后区隆突和小棘。鳞纹嵴顶上的齿状粒突,其形态特征和排列方式可作为辅助鉴别疑难种类的依据。鳞纹和后区隆突上的伸缩缝,作者认为对鳞片的伸缩起着柔软缓冲作用。     

有鳞目动物鳞片表面超微结构的适应性进化

爬行动物鳞片的微结构是对环境的一种适应。本研究运用扫描电子显微镜观察了北草蜥(Takydromus septentrionalis)、脆蛇蜥(Dopasia harti)和王锦蛇(Elaphe carinata)头部、背部和腹部鳞片的微皮纹结构及感受器特征。结果表明,3个物种的微皮纹和感受器存在种间差异。北草蜥和王锦蛇背部及腹部微皮纹均为狭长带状,脆蛇蜥为不规则多边形。北草蜥和王锦蛇颔片上有感受器,北草蜥无。脆蛇蜥腹部微皮纹上无小齿状凸起,北草蜥和王锦蛇有,与北草蜥相比王锦蛇的小齿状凸起更宽更长。王锦蛇的眼部微皮纹为向上竖起的脊,而其他部位的鳞片为具有小齿状凸起的狭长带状结构。本研究共收集整理17科99种的背鳞微皮纹数据和8科25种的感受器数据,对微皮纹特征和感受器形态进行祖先重建发现,狭长带状背鳞微皮纹主要存在于蜥蜴科(Lacertidae)、游蛇科(Colubridae)和石龙子科(Scincidae)中,而鬛蜥科(Agamidae)、蛇蜥科(Anguidae)、蟒蛇科(Boidae)以及蝰蛇科(Viperidae)的大多为多边形;较原始的感受器形态为无感觉毛的透镜状,这一结构在有...     

游蛇科8种蛇的鳞片显微皮纹结构观察

游蛇科8种蛇,分别为云南沾益采集的棕网腹链蛇(Hebius johannis),云南铜壁关采集的卡西腹链蛇(H.khasiensis)、八线腹链蛇(H.octolineatum)、双带腹链蛇(H.parallela)、八莫过树蛇(Dendrelaphis subocularis),云南澜沧采集的大眼斜鳞蛇(Pseudoxenodon macrops),云南昆明采集的虎斑颈槽蛇(Rhabdophis tigrinus),云南临沧采集的中国小头蛇(Oligodon chinensis)。于2014年4月对其背鳞显微皮纹结构进行扫描电镜观察,8种蛇每种使用1个个体,每个个体分别从蛇体的前、中、近尾部各采集3枚鳞片,共观察9枚鳞片。低倍下观察到鳞棱,高倍下观察到纵行小棱、条索、横纹、小孔结构,这些结构存在种间差异。八莫过树蛇和中国小头蛇无鳞棱,但是其余6种蛇鳞棱十分明显;大眼斜鳞蛇的纵行小棱短于100μm,其余7种蛇的纵行小棱均长于100μm;仅八莫过树蛇和双带腹链蛇背鳞上有明显的条索结构;八莫过树蛇的横纹为平缓波纹,其余7种蛇的横纹为"U"形波纹;小孔的形状、排列位置在种间变化较大,小孔的密集程度以八莫过树蛇、大眼斜鳞蛇、虎斑颈槽蛇较高。在8种蛇中,八莫过树蛇背鳞的显微皮纹结构最为复杂,可能与其栖息在热带雨林中有关。     

南极鳕鳞片表面结构的光镜和扫描电镜的观察

本文对南极鳕鳞片表面结构进行了光镜和扫描电镜形态学的初步研究。观察同一鱼体上圆鳞和栉鳞的各自形态,论述了两种鳞片年轮的特点及鳞峭、鳞沟、鳞棘等的特征。经过观察分析,认为年轮的断裂型即为生殖轮,生殖轮的出现将是性成熟的标志。     

铜蜓蜥鳞片变异研究

对一个物种变异特征的研究在种及种下分类工作中有着重要的意义。本文以中国科学院成都生物研究所（CIB）两栖爬行动物标本馆馆藏铜蜓蜥（Sphenomorphus indicus）标本430号为对象,对其鳞片数目及排列的变异做了统计分析。鳞被特征是有鳞目蜥蜴亚目物种重要的鉴别特征,本文主要研究了铜蜓蜥吻鳞、上鼻鳞、额鼻鳞、额鳞、前额鳞、眶上鳞、额顶鳞、顶间鳞、顶鳞、颈鳞、鼻鳞、颊鳞、颞鳞、上唇鳞、下唇鳞、颏鳞、后颏鳞、颔片、背中线鳞、腹中线鳞、环体一周鳞的特征及其变异情况,并运用Microsoft Office Excel2003计算鳞片的变异频率、变异范围、平均鳞片数目。根据鳞片变异频率的不同可将其分为三类：数量恒定无变异的鳞片、可出现变异的鳞片、绝对有变异的鳞片。发现：①过去文献对于颈鳞有无的判断存在不足;②西藏墨脱地区标本头部眶上鳞、额顶鳞、顶间鳞数目和排列方式的特殊变异现象。研究结果为今后铜蜓蜥的鉴别提出了更准确的标准,并建议今后应对铜蜓蜥西藏墨脱居群进行更深入的研究。以解释其头部鳞片特殊变异的成因。     

牙鲆、大黄鱼和小黄鱼不同部位鳞片类型的比较

真骨鱼类的骨鳞有圆鳞和栉鳞两种类型,观察了大黄鱼(Larimichthys crocea)和小黄鱼(Pseudosciaena polyactis)成体的鳞片类型,发现同一个体同时存在圆鳞和栉鳞,有典型的圆鳞和栉鳞结构,也有两者的过渡型形态。而对100日龄和成体牙鲆(Paralichthys olivaceus)不同部位鳞片类型的观察发现,100日龄牙鲆眼侧存在圆鳞向栉鳞过渡的Ⅲ型鳞片、Ⅳ型初始栉鳞和Ⅴ型典型栉鳞,而成体牙鲆有眼侧仅覆盖Ⅴ型典型栉鳞,推测栉鳞和圆鳞可能存在发育上的联系。通过统计大黄鱼和小黄鱼不同部位的圆鳞和栉鳞数量,发现二者体表栉鳞数量均为从头部到尾部依次减少,而背部与腹部之间没有明显差异。     

中国有鳞杜鹃叶背鳞片显微形态研究

报道了国产有鳞杜鹃５７个种的叶背鳞片显微形态特征;比较了髯花杜鹃组与杜鹃组中２２个亚组叶背鳞片的显微形态特征;依据鳞片脐的直径与边缘宽度比,边缘形态及其他特征,可分为五大类型;圆鳞片、大脐鳞片、小脐鳞片、放射状鳞片、红色厚鳞片,其中前三个还可分为１０个小型。讨论了鳞片演化的趋势：（１）小圆鳞片是最原始的,小脐深裂鳞片是最进步的;（２）脐演化方向是大→小脐;（３）边缘演化方向是无边缘→有边缘、全缘→     

绿安乐蜥微皮纹和皮肤感受器形态学与组织学研究

运用扫描电镜、组织切片、显微拍照等实验方法对绿安乐蜥Anolis carolinensis背部未蜕皮和蜕皮皮肤微皮纹及皮肤感受器形态、组织学进行了研究,发现未蜕皮和蜕皮皮肤的微皮纹和皮肤感受器特征、大小没有显著区别,因此蜕皮组织是研究这类结构的理想实验材料;鳞片表面的棘突与支柱构成了网状的三维结构,凹窝处有1～2个皮肤感受器;皮肤感受器真皮层内有真皮小体,绞合区域和皮肤感受器β-角质层和中层明显变薄。这些特点表明,绿安乐蜥背部表皮结构与栖息地及变色能力密切相关,在保护皮肤、实现自身伪装和调节体温等方面具有重要作用,研究结果有助于进一步了解其变色机理,能够为开发自主变色材料提供生物学依据,对于研究珍稀物种皮肤微观结构具有重要借鉴意义。     

大鳞副泥鳅鳞片表面结构的扫描电镜观察

对大鳞副泥鳅的鳞片作了扫描电镜观察。结果表明,大鳞副泥鳅具圆鳞;基区、侧区和顶区均具有辐射沟及环沟,二者交织成网状,将鳞片分割成块状,可增加鳞片的柔软度;次级辐射沟发出部位可作为确定年轮的主要依据。     

Scale microornamentation of uropeltid snakes

Microornamentation was examined on the exposed oberhautchen surface of dorsal, lateral, and ventral scales from the midbody region of 20 species of the fossorial snake family Uropeltidae and seven species of fossorial scolecophidian and anilioid outgroups. No substantial variation was observed in microornamentation from the different areas around the midbody circumference within species. All oberhautchen cells were flat and exhibited no major surface features other than occasional posterior margin denticulations, small pores/pits, and narrow, low ridges. This is largely consistent with the hypothesis that friction reduction and dirt shedding are the main selective pressures on microornamentation, given that reducing shine is not of key importance in fossorial animals. Variations among taxa were observed in the shape and size of oberhautchen cells, in the presence of pores/pits, in the presence and size of denticulations on posterior cell margins, and in the level or imbricate nature of cell borders. Six microornamentation characters were formulated, scored, and plotted onto a selected phylogeny. Character evolution and phylogenetic signal were explored, accepting the incomplete understanding of intraspecific variation and of uropeltid interrelationships. There is evidence that all but one of these characters evolved homoplastically, probably by multiple independent origin. There is no clear evidence for character state reversal, but greater phylogenetic resolution is required to test this further. Phylogenetic signal appears to exist in some instances, including possible microornamentation synapomorphies for Uropeltidae and Melanophidium. These derived character states are found elsewhere within Squamata. A microornamentation of narrow, finely, and regularly spaced ridges is associated with scale iridescence. These ridges, and possibly pores/pits, are also associated with scales that are less wettable, and that therefore might be expected to be better at shedding dirt in moist conditions. Testable hypotheses are presented that might explain minor variations in the form of ridges and pits among uropeltids.     

History and function of scale microornamentation in lacertid lizards

Differences in surface structure (ober-hautchen) of body scales of lacertid lizards involve cell size, shape and surface profile, presence or absence of fine pitting, form of cell margins, and the occurrence of longitudinal ridges and pustular projections. Phylogenetic information indicates that the primitive pattern involved narrow strap-shaped cells, with low posteriorly overlapping edges and relatively smooth surfaces. Deviations from this condition produce a more sculptured surface and have developed many times, although subsequent overt reversals are uncommon. Like variations in scale shape, different patterns of dorsal body microornamentation appear to confer different and conflicting performance advantages. The primitive pattern may reduce friction during locomotion and also enhances dirt shedding, especially in ground-dwelling forms from moist habitats. However, this smooth microornamentation generates shine that may compromise cryptic coloration, especially when scales are large. Many derived features show correlation with such large scales and appear to suppress shine. They occur most frequently in forms from dry habitats or forms that climb in vegetation away from the ground, situations where dirt adhesion is less of a problem. Microornamentation differences involving other parts of the body and other squamate groups tend to corroborate this functional interpretation. Microornamentation features can develop on lineages in different orders and appear to act additively in reducing shine. In some cases different combinations may be optimal solutions in particular environments, but lineage effects, such as limited reversibility and different developmental proclivities, may also be important in their genesis. The fine pits often found on cell surfaces are unconnected with shine reduction, as they are smaller than the wavelengths of most visible light.     

Ultrastructural contributions to an understanding of the cellular mechanisms involved in lizard skin shedding with comments on the function and evolution of a unique Lepidosaurian phenomenon

Previous reports on the fine structure of lizard epidermis are confirmed and extended by SEM and TEM observations of cell differentiation and the form of shed material from the American anole Anolis carolinensis. Attention is drawn to two issues: 1) the tips of the spinules arising from the mature oberhautchen are markedly curved; this morphology can be seen during differentiation; 2) the median keels of scales from all parts of the body show “naked” oberhautchen cells that lack characteristic spinules, but have a membrane morphology comprising a complex system of serpentine microridges. Maderson's ([1966] J. Morphol. 119:39–50) “zip-fastener” model for the role of the shedding complex formed by the clear layer and oberhautchen is reviewed and extended in the light of recent SEM data. Apparently periodic lepidosaurian sloughing permits somatic growth; understanding how the phenomenon is brought about requires integration of data from the organismic to the molecular level. The diverse forms of integumentary microornamentation (MO) reported in the literature can be understood by considering how the cellular events occurring during the renewal phase prior to shedding relate to the emergence of the form-function complex of the β-layer, which provides physical protection. Issues concerning the evolutionary origin of lepidosaurian skin-shedding are discussed. J. Morphol. 236:1–24, 1998. © 1998 Wiley-Liss, Inc.     

Scanning electron microscopy of scales from different body regions of three lizard species

The Oberhautchen of scales from the dorsal, parietal, and ventral regions of Sceloporus occidentalis (Iguanidae), Gerrhonotus multicarinatus (Anguinidae), and Anniella pulchra (Anniellidae) were examined with a scanning electron microscope. At low magnification, all scales of S. occidentalis exhibit well-defined outlines of cells belonging to the Oberhautchen layer and the previously overlying clear layer. The dorsal and parietal cells of this species exhibit a minutely dentate Oberhautchen that forms tooth-like spinules 0.2 to 0.5 μ long and arranged in irregular rows. Minute pits 0.1 to 0.3 μ in diameter characterize the Oberhautchen of a ventral scale. Cell outlines are not evident on the scales of G. multicarinatus. The Oberhautchen of dorsal and parietal scales of this species is prominently laminated. Laminae are less prominent on scales of the lateral fold, and no intrinsic surface structure is evident on a ventral scale. In contrast, the fossorial anguinomorph Anniella pulchra exhibits Oberhautchen surfaces with practically no intrinsic microornamentation. However, what appear to be outlines of Oberhautchen cells are visible on the dorsal and ventral scales. These observations suggest that modifications of Oberhautchen microornamentation may have evolved to reduce friction with the substrate or other scales. The lack of pronounced microornamentation of the Oberhautchen on some body scales may indicate that a complex interdigitation between clear layer and Oberhautchen cells is not essential to the sloughing process.     

Keratohyalin-like granules in lizard epidermis: evidence from cytochemical, autoradiographic, and microanalytic studies

Epidermal sloughing in lizards is determined by the formation of an intraepithelial shedding complex in which keratohyalin-like granules are formed. The chemical nature of these granules is unknown, as is their role in keratinization. The goal of this study was to test whether they contain some amino acids similar to those found in mammalian keratohyalin. The embryonic and regenerating epidermis of lizards are useful systems to study the formation of these granules. Histochemically keratohyalin-like granules react to histidine and contain some sulfhydryl groups (cysteine). X-ray microanalysis shows that these granules contain sulfur and often phosphorus, two elements also present in the mature clear, oberhautchen, and beta layer. Instead the mesos, alpha, and lacunar layers contain only sulfur. Most sulfur is probably in a disulfide-bonded form, particularly in mature cells of the shedding complex, in large keratohyalin-like granules, and in the beta-keratin layer. Early differentiating beta-keratin cells have the maximal incorporation of tritiated proline, whereas tritiated arginine is slightly more concentrated in the basal layer of the epidermis. A high uptake of tritiated histidine is observed mainly in keratohyalin-like granules of the clear layer, but also in the oberhautchen layer and forming the alpha-lacunar layer. Immunogold electron microscopy shows that keratohyalin-like granules do not localize keratin but are embedded within a keratin network. These results suggest that keratohyalin-like granules of lizards, like mammalian keratohyalin, contain some sulfur-rich and histidine-rich proteins. These granules participate in the process of hardening of the clear layer that molds the spinulae of the deeper oberhautchen to form the superficial microornamentation.     

Myosin,microtubules, and microfilaments: co-operation between cytoskeletal components during cambial cell division and secondary vascular differentiation in trees

The immunolocalisation of unconventional myosin VIII ('myosin') in the cells of the secondary vascular tissues of angiosperm (Populus tremula L. x P. tremuloides Michx. and Aesculus hippocastanum L.) and gymnosperm (Pinus pinea L.) trees is described for the first time and related to other cytoskeletal elements, as well as to callose. Both myosin and callose are located at the cell plate in dividing cambial cells, whereas actin microfilaments are found alongside the cell plate; actin and tubulin are both associated with the phragmoplast. Myosin and callose also localise to the plasmodesmata-rich pit fields in the walls of living cells, which are particularly abundant within the common walls between ray cells and between ray cells and axial parenchyma cells in the phloem and xylem. In those xylem ray cells that contact developing vessel elements and tracheids, myosin, tubulin, actin and callose are localised at the periphery of developing contact and cross-field pits; the respective antibodies also highlight the bordered pits between vessels and between tracheids. The aperture of the bordered pits, whose diameter diminishes as the over-arching border of these pits develops, also houses myosin, actin and tubulin. Myosin, actin and callose are also found together around the sieve pores of sieve elements and sieve cells. We suggest that an acto-myosin contractile system (a 'plant muscle') is present at the cell plate, the sieve pores, the plasmodesmata within the walls of long-lived parenchyma cells, and at the apertures of bordered pits during their development.     

High molecular mass glycoproteins associated with the siliceous scales and bristles of Mallomonas splendens (Synurophyceae) may be involved in cell surface development and maintenance

The elaborate scale case of Mallomonas splendens (Synurophyceae) consists of an overlapping arrangement of siliceous scales. In addition, siliceous bristles are attached to specialized base plate scales located at both the anterior and posterior ends of the cells. We have generated monoclonal antibodies against molecules associated with the scale case of M. splendens. One of these antibodies, designated MsS.H9, labelled a proteinaceous epitope of high-molecular-mass cell surface glycoproteins. Immunofluorescence and immunoelectron microscopy demonstrated that only two regions of M. splendens scale cases were labelled by MsS.H9, namely, the upper surface of the scales that contact neighboring scales and the bases of the bristles. Immunoelectron microscopy using thin sections of M. splendens cells showed these labelling sites corresponded to the amorphous material at the sites of scale-to-scale overlap and to a fibrillar complex located at scale-to-bristle attachment sites. Scales and bristles of M. splendens are formed within the cell, in silica deposition vesicles. Immunolabelling of cell sections containing developing scales and bristles showed that MsS.H9 labelling sites were present very early in the formation of these cell surface components. MsS.H9 labelling was also found associated with developing flagellar hairs whereas no labelling was detected on these structures after their deployment onto the flagellum. The location of MsS.H9 labelling sites strongly suggests that the molecule(s) recognized by the antibody plays a role in the adhesion of the individual components making up the scale case of M. splendens.Abbreviations CER chloroplast endoplasmic reticulum - ER endoplasmic reticulum - SDV silica deposition vesicle This work was supported by a grant from the Australian Research Council to R.W. We thank Dr. P. L. Beech for Fig. 13, Dr. L. Perasso for technical assistance and the Plant Cell Biology Group for the use of their monoclonal facilities.     

Potassium-dependent assembly of coated pits: new coated pits form as planar clathrin lattices

Previous studies have shown that when human fibroblasts are depleted of intracellular K+, coated pits disappear from the cell surface and the receptor-mediated endocytosis of low density lipoprotein (LDL) is inhibited. We have now used the K+ depletion protocol to study several aspects of coated pit function. First, since coated pits rapidly form when K+-depleted fibroblasts are incubated in the presence of 10 mM KCl, we studied the sequence of assembly of coated pits as visualized in carbon-platinum replicas of inner membrane surfaces from cells that had been incubated in the presence of K+ for various times. New coated pits initially appeared as planar clathrin lattices that increased in size by the formation of polygons at the margin of the lattice. Once the lattice reached a critical size it invaginated to form coated vesicles. Second, we determined that LDL-ferritin can induce clustering of LDL receptors over noncoated membrane on the surface of K+-depleted fibroblasts; however, when these cells are subsequently incubated in the presence of K+, these clusters become associated with newly formed coated pits and are internalized. Finally, we determined that K+ depletion inhibits the assembly of coated pits, but that existing coated pits in K+-depleted cells are able to internalize LDL. These results suggest that the clathrin lattice of coated pits is actively involved in membrane shape change during endocytosis and that the structural proteins of the lattice are cyclically assembled and disassembled in the process.     

Differentiation of snake epidermis, with emphasis on the shedding layer

Little is known about specific proteins involved in keratinization of the epidermis of snakes. The presence of histidine-rich molecules, sulfur, keratins, loricrin, transglutaminase, and isopeptide-bonds have been studied by ultrastructural autoradiography, X-ray microanalysis, and immunohistochemistry in the epidermis of snakes. Shedding takes place along a shedding complex, which is composed of two layers, the clear and the oberhautchen layers. The remaining epidermis comprises different layers, some of which contain beta-keratins and others alpha-keratins. Weak loricrin, transglutaminase, and sometimes also iso-peptide-bond immunoreactivities are seen in some cells, lacunar cells, of the alpha-layer. Tritiated histidine is mainly incorporated in the shedding complex, especially in dense beta-keratin filaments in cells of the oberhautchen layer and to a small amount in cells of the clear layer. This suggests the presence of histidine-rich, matrix proteins among beta-keratin bundles. The latter contain sulfur and are weakly immunolabeled for beta-keratin at the beginning of differentiation of oberhautchen cells. After merging with beta cells, the dense beta-keratin filaments of oberhautchen cells become immunopositive for beta-keratin. The uptake of histidine decreases in beta cells, where little dense matrix material is present, while pale beta-keratin filaments increase. During maturation, little histidine labeling remains in electron-dense areas of the beta layer and in those of oberhautchen spinulae. Some roundish dense granules of oberhautchen cells rich in sulfur are negative to antibodies for alpha-keratin, beta-keratin, and loricrin. The granules eventually merge with beta-keratin, and probably contribute to the formation of the resistant matrix of oberhautchen cells. In conclusion, beta-keratin, histidine-rich, and sulfur-rich proteins contribute to form snake microornamentations.