中国林蛙蝌蚪的口器发育

采用扫描电镜和组织学技术观察了中国林蛙(Rana chensinensis)蝌蚪发育过程中口器外部形态结构的变化,以及中国林蛙蝌蚪口器内部结构特征.结果表明,在口器发育的初期,角质颌最先出现,接着出现唇乳突以及唇齿;在变态高峰期(G4l～G42),口器结构如唇齿、角质颌和唇乳突则是按以下顺序消失的,即唇齿最先消失,其次...     

杂色鲍鳃的显微与亚显微结构

本文采用光镜和电镜方法,研究了杂色鲍（Haliotis diversicolor）鳃的显微和亚显微结构。结果表明,杂色鲍的鳃为一对不等大的双栉状鳃,各鳃由鳃轴和两侧列生的状鳃叶组成,鳃叶上皮为单层上皮组织结构,细胞类型主要为：纤毛细胞、立方细胞、腺细胞;鳃轴上皮为鳃叶上皮的延伸,亦是单层上皮组织,细胞类型主要有：纤毛细胞、微绒毛立方细胞和腺细胞等;鳃叶远轴端游离缘表皮之下,含有几丁质杆支撑的血腔,血腔内可见血细胞及未分化的间充质细胞,血腔之间有平滑肌纤维束和疏松结缔组织,疏松结缔组织内含胶原纤维、纤维细胞、成纤维细胞、脂肪细胞及未分化的间充质细胞等;鳃轴的皮下组织也含有几丁质杆、平滑肌纤维、疏松结缔组织及其间的血腔结构。     

Microstructure of scales in selected lizard species

In the present study, it was hypothesized that micromorphology of the surface of many lizard scales appears to mimic the topography of the habitat in which they live. Many authors have suggested that the microstructure of the superficial surface of scales have undergone important adaptations and have functional value in lizards. In this study, we investigated the variation and adaptation of the micromorphology and microstructure of the superficial surface of the dorsal and ventral scales from the mid-body region of Stellagama stellio (Agamidae), Stenodactylus petrii (Gekkonidae), Acanthodactylus boskianus (Lacertidae), Eumeces schneideri (Scincidae), Trachylepis quinquetaeniata (Scincidae), Scincus scincus (Scincidae), Varanus griseus (Varanidae), Chameleo chameleon (Chamaeleonidae). Skin specimens were prepared and analyzed using scanning electron microscopy. The dorsal and ventral scale surfaces had microstructure in the studied species and they exhibited unique patterns that somewhat resembled the topography of the microhabitats in which they lived. Similarity was detected in the three most related species, those having a common family, Scincidae. Ecomorphological relationships were detected between the dorsal and ventral scale microstructures and microhabitats. We conclude that environmental factors have observable influences on the microstructure of lizard scales.     

Simultaneous extension of both basic microstructural components in scleractinian coral skeleton during night and daytime,visualized by in situ 86Sr pulse labeling

Using in situ (12 h) pulse-labeling of scleractinian coral aragonitic skeleton with stable ⁸⁶Sr isotope, the diel pattern of skeletal extension was investigated in the massive Porites lobata species, grown at 5 m depth in the Gulf of Eilat. Several microstructural aspects of coral biomineralization were elucidated, among which the most significant is simultaneous extension of the two basic microstructural components Rapid Accretion Deposits (RAD; also called Centers of Calcification) and Thickening Deposits (TD; also called fibers), both at night and during daytime. Increased thickness of the ⁸⁶Sr-labeled growth-front in the RADs compared to the adjacent TDs revealed that in this species RADs extend on average twice as fast as TDs. At the level of the individual corallite, skeletal extension is spatially highly heterogeneous, with sporadic slowing or cessation depending on growth directions and skeletal structure morphology. Daytime photosynthesis by symbiotic dinoflagellates is widely acknowledged to substantially increase calcification rates at the colony and the corallite level in reef-building corals. However, in our study, the average night-time extension rate (visualized in three successive 12 h pulses) was similar to the average daytime extension (visualized in the initial 12 h pulse), in all growth directions and skeletal structures. This research provides a platform for further investigations into the temporal calibration of coral skeletal extension via cyclic growth increment deposition, which is a hallmark of coral biomineralization.     

Reversible immobilization of glucoamylase onto magnetic polystyrene beads with multifunctional groups

A novel and simple process for the surface functionalization of micron-sized monodisperse magnetic polystyrene (PS) microbeads was reported. The polystyrene seed particles were prepared prior to the dispersion polymerization method. Afterwards, series of surface chemical modifications on polystyrene microspheres were conducted, and three end-functional microspheres with carboxyl, imidazolyl and sulphydryl groups were obtained. The functional magnetic polystyrene microspheres were prepared by impregnation and subsequent precipitation of ferric and ferrous ions into the polystyrene particles. Finally, the functional magnetic polystyrene was used for the reversible immobilization of glucoamylase via metal-affinity adsorption. The results indicated that the obtained immobilized glucoamylase presented excellent reusability, applicability, magnetic response and regeneration of supports. The magnetic PS microspheres retained >65% of its initial activity at 65 °C over 6 h; and the lowest residual activity of immobilized glucoamylase prepared by regenerated supports still remained about 50% of the initial activity after the 10th cycles.     

乌梢蛇精巢显微结构的年周期变化

用光镜观察了乌梢蛇(Zaocys dhumnades)精巢显微结构的年周期变化,并结合精巢重量、精巢体积及精巢系数的年周期变化探讨了其生殖规律。结果表明,乌梢蛇精巢重量、精巢体积、精巢系数、曲细精管直径、生精上皮厚度及组成均具有明显的季节性变化。据此将乌梢蛇精巢的年周期活动划分为6个时期,其精子发生属于非连续型,生殖周期的类型属于交配后型。用精巢系数的年周期变化作为参数来判定精子发生进程是可靠的。     

斜带石斑鱼黏膜免疫系统结构的研究

对斜带石斑鱼皮肤、眼角膜、鳃、前肠及后肠等黏膜相关免疫组织结构进行了研究。通过组织切片的H E染色及透射电镜的观察 ,描述了黏膜组织的显微结构、主要免疫相关细胞在黏膜组织中的分布情况及各免疫细胞的超微结构。结果表明黏膜组织中存在杯状细胞、淋巴细胞、巨嗜细胞、单核细胞、嗜曙红细胞、嗜中性粒细胞等免疫相关细胞 ,具有在黏膜局部独立完成免疫应答的细胞基础。另外 ,还观察到了皮肤表皮对异物的吞噬过程。本文还就黏膜免疫组织的非特异和特异性免疫应答 ,以及黏膜免疫是否独立于系统免疫等问题进行了讨论。     

Measurement of particle diameter of <Emphasis Type="Italic">Lactobacillus acidophilus</Emphasis> microcapsule by spray drying and analysis on its microstructure

Lactobacillus acidophilus, as a probiotic, is widely used in many functional food products. Microencapsulation not only increases the survival rate of L. acidophilus during storage and extends the shelf-life of its products, but also optimal size microcapsule makes L. acidophilus have an excellent dispersability in final products. In this paper, L. acidophilus was microencapsulated using spray drying (inlet air temperature of 170°C; outlet air temperature of 85–90°C). The wall materials used in this study were β-cyclodextrin and acacia gum in the proportion of 9:1 (w/w), and microcapsules were prepared at four levels of wall materials (15, 20, 25 and 30% [w/v]) with a core material concentration of 6% (v/v). The microcapsule diameters were measured by Malvern’s Mastersizer-2000 particle size analyzer. The results showed that the particle diameters of microcapsule were mostly within 6.607 μm and 60.256 μm and varied with 2.884–120.226 μm (the standard smaller microcapsule designated as <350 μm). Through comparison of microcapsule size and uniformity with different concentration of wall materials, we concluded that the optimal concentration of wall material was 20% (w/v), which gave microcapsule with a relatively uniform size (averaging 22.153 μm), and the number of surviving encapsulated L. acidophilus was 1.50 × 10⁹ c.f.u./ml. After 8 weeks storage at 4°C, the live bacterial number was above 10⁷ c.f.u./ml, compared with unencapsulated L. acidophilus, 10⁴–10⁵ c.f.u./ml. Through the observation of scanning electron microscopy, we found that the shapes of microcapsule were round and oval, and L. acidophilus cells located in the centre of microcapsule.     

How the microstructure of dentine can contribute to reconstructing developing dentitions and the lives of hominoids and hominins

Accounts of dentine microstructure are less well established in the primate life history literature than those of enamel microstructure. The aim of this paper is to draw some basic comparisons between enamel and dentine, but at the same time to show how dentine microstructure can make a major but different contribution to reconstructing past lives than enamel can. Dentine has both an organic and an inorganic component. The organic component contains growth factors, stable isotopes and DNA that survive long after death. The mineral component contains trace elements and preserves an incremental record of tooth growth. These can be used to put a time scale to many past events when the chemistry or microstructure of dentine has become altered during tooth growth. Dentine microstructure allows us to reconstruct tooth root growth in the past and has contributed to a fuller understanding of the modular nature of developing dentitions among hominoids and hominins.     

Microstructure and mechanical properties of rostrum in Cyrtotrachelus longimanus (Coleoptera: Curculionidae)

The microstructure, composition and mechanical properties of the rostrum in Cyrtotrachelus longimanus (JHC Fabre) were studied utilizing light, fluorescent, scanning electron microscopy (SEM) and energy-dispersive spectroscopy. SEM images show the morphological characteristics of rostrum’s cross section; it is a typical lightweight multilayer structure – one rigid exocuticle layer and dense endocuticle layers, which construct unevenly overlapping fiber structures. The composition analysis of the rostrum shows that it is mainly composed of C, H, N, O, as well as some metal elements and microelements, such as Mg, Si, Zn, Ca and Na, which contribute to its mechanical performance. The mechanical properties of the rostrum were tested by the electronic universal testing machine, which shows it has high-specific strength and is almost the same as that of the stainless steel. The results may provide a biological template to inspire biomimetic lightweight structure design.