Investigation of the enzymatic digestion of plant cell walls using reflectance Fourier Transform Infrared spectroscopy

A method has been developed to determine the reflectance Fourier Transform Infrared spectra of plant cells grown in vitro and of the protoplasts released from such cells by enzymatic digestion. It is demonstrated that there is a smooth and reproducible transition in spectral detail as enzymatic digestion procedes. Reflectance Fourier Transform Infrared spectroscopy has been used to monitor the progress of protoplast release during enzymatic digestion of cell wall material.Abbreviations FTIR Fourier Transform Infrared - SEM Scanning Electron Microscope     

A view of tropical biology through the electron microscope

The first electron microscope in Costa Rica was a donation from the government of Japan through its International Cooperation Agency (JICA) in 1974. This donation made possible the consolidation of what was to become the University of Costa Rica's Electron Microscope Unit (UME). Within three years the first scientific papers were published, dealing with ultrastructural aspects of "Corn's rayado fino virus" and rotavirus, viral agent of human diarrhea. Subsequent papers out of the UME were published for the most part in the Journal of Tropical Biology, totaling at least 50 in that journal alone by the year 2000. With the recent acquisition of Energy Dispersive Spectrometer to coupled in transmission electron microscope and scanning electron microscope to X ray analysis, the data acquisition of the UME has been greatly enhanced, making possible to analyze both structure and elemental chemical composition in a specimen. Other applications of this new technology include studies of environmental pollution with heavy metals, such as comparative analysis of residues on leaves from urban areas and those on leaves from primary forest.     

The new insight on ultrastructure of C-type starch granules revealed by acid hydrolysis

C-type starch granule could be considered as the mixture of A- and B-polymorphs. The ultrastructure of C-type starch granules has not been elucidated detailedly by comparison with that of A- or B-type starch. To better understand the ultrastructure of C-type starch granules, Environment Scanning Electron Microscope (ESEM) and Field Emission Gun Transmission Electron Microscope (FEG-TEM) have been used to analyze the conformation and ultrastructure of C-type starch granule from Rhizoma Dioscorea during acid hydrolysis. SEM results showed that the amorphous areas were mainly located interior part of C-type starch granules whereas the crystalline regions were found mostly in the peripheral region of the granules. The grain size can be confirmed to be about 4.5-9 nm from the HR-TEM micrographs. The nanocrystals from acid-thinned starch displayed the typical face-centered cubic structure. This selected area electron diffraction patterns showed that individual C-type starch granule consisted of A- and B-type polymorphs.     

金花茶组植物花粉扫描电镜研究(一)

植物花粉的形态特征具有种属特异性。本文用扫描电子显微镜报道了金花茶组８种植物花粉的形态特征。结果表明,８种金花茶组植物的花粉外壁纹饰可分为三大类型：疣状纹饰（块状纹饰）类型、脑纹状纹饰（蠕虫状纹饰）类型及拟网状纹饰类型。不同种植物花粉外壁纹饰存在一定差异,三大类型花粉外壁纹饰存在一定的演化关系,可为种间分类及演化关系提供依据。     

川东中侏罗统新田沟组介形类化石壳体方解石化特征及元素成分初步分析

首次利用扫描电子显微镜观察川东新田沟组介形类化石的保存情况,并利用X射线能谱分析部分化石的元素含量及分布。研究发现新田沟组介形类壳体绝大部分方解石化,不同层位介形类壳质方解石化有所不同,且方解石化特点显示其可能与有机质作用有关。通过与前人研究结果对比发现,新田沟组壳体保存处在介形虫壳体埋藏作用的第二阶段和第三阶段。     

A critical overview of ESEM applications in the biological field

Scanning Electron Microscope (SEM) is a powerful research tool, but since it requires high vacuum conditions, the wet materials and biological samples must undergo a complex preparation that limits the application of SEM on this kind of specimen and often causes the introduction of artifacts. The introduction of Environmental Scanning Electron Microscope (ESEM), working in gaseous atmosphere, represented a new perspective in biological research. Despite the fact that many biological applications have demonstrated the convenience of ESEM, the full potentialities of this technology are still under investigation. In this review, the exploration of the recent literature data confronted with the first results obtained in our experimental work suggest that ESEM represents an important extension of conventional scanning microscopy.     

Electron Tomography in Plant Cell Biology

This review focuses on the contribution of electron tomography-based techniques to our understanding of cellular processes in plant cells. Electron microscopy techniques have evolved to provide better three-dimensional resolution and improved preservation of the subcellular components. In particular, the combination of cryofixation/freeze substitution and electron tomography have allowed plant cell biologists to image organelles and macromolecular complexes in their native cellular context with unprecedented three-dimensional resolution （4-7 nm）. Until now, electron tomography has been applied in plant cell biology for the study of cytokinesis, Golgi structure and trafficking, formation of plant endosome/prevacuolar compartments, and organization of photosynthetic membranes. We discuss in this review the new insights that these tomographic studies have brought to the plant biology field.     

Ultrastructural changes in spermatozoa of the Brush-tailed possum,Trichosurus vulpecula (Marsupialia), during epididymal transit

Summary During epididymal transit, a fibre network and an array of vesicles develop in the posterior two-thirds of the midpiece in sperm of the Brush-tailed possum, Trichosurus vulpecula. The fibre network is developed by the time the sperm reach the corpus epididymidis, and is composed of evenly spaced, helically arranged fibres lying immediately beneath the plasma membrane. The angle of these fibrous helices is always counter to that of the underlying mitochondrial helix. Separating the fibre network from the mitochondria is a layer of granular material which develops at the same time, and over the same length of the midpiece as the fibre network.A somewhat tenuous fibre network is found between the fibrous sheath and plasma membrane in the anterior principal piece of sperm from all regions of the epididymis.The array of vesicles is developed by the time sperm reach the cauda epididymidis. The vesicles resemble pinocytotic vesicles; some appear as invaginations of the plasma membrane, and are open to the medium surrounding the spermatozoon by a narrow neck, while others are entirely enclosed within the spermatozoon, and lie at varying distances between the plasma membrane and the layer of granular material.The authors would like to acknowledge the assistance of Miss Dianne Higginbotham of the Electron Microscope Unit, University of Sydney for expert assistance with the scanning electron microscopy. Also to Dr. D.J.H. Cockayne, Director of the Electron Microscope Unit, for use of the transmission electron microscope facilities.     

Light Trapping Effect in Wing Scales of Butterfly Papilio peranthus and Its Simulations

Broadband light trapping effect and arrays of sub-wavelength textured structures based on the butterfly wing scales are applicable to solar cells and stealth technologies. In this paper, the fine optical structures in wing scales of butterfly Papilio peranthus, exhibiting efficient light trapping effect, were carefully examined. First, the reflectivity was measured by reflectance spectrum. Field Emission Scanning Electronic Microscope (FESEM) and Transmission Electron Microscope (TEM) were used to observe the coupling morphologies and structures of the scales. Then, the optimized 3D model of the coupling structure was created combining Scanning Electron Microscope (SEM) and TEM data. Afterwards, the mechanism of the light trapping effect of these structures was analyzed by simulation and theoretical calculations. A multilayer nano-structure of chitin and air was found. These structures are effective in increasing optical path, resulting in that most of the incident light can be trapped and adsorbed within the structure at last. Furthermore, the simulated optical results are consistent with the experimental and calculated ones. This result reliably confirms that these structures induce an efficient light trapping effect. This work can be used as a reference for in-depth study on the fabrication of highly efficient bionic optical devices, such as solar cells, photo detectors, high-contrast, antiglare, and so forth.     

Distribution of acetylcholinesterase in extraocular muscle fibres of the rat

Summary The distribution of acetyleholinesterase in the fine structure of the extraocular muscle of the rat was studied using acetylthiocholine iodide as a substrate together with selective inhibitors.Acetylcholinesterase was observed in the membranes of the transverse elements of the sarcoplasmic reticulum and in the region of the A—I junction.The author thanks to Professor Antti Telkkä, M. D., Head of the Electron Microscope Laboratory, University of Helsinki, for permission to use the facilities of the laboratory.     

Seed morphology in New WorldAntirrhineae (Scrophulariaceae): Systematic and phylogenetic implications

Seeds of 39 species representing all native genera and sections of New WorldAntirrhineae were examined with the Scanning Electron Microscope and Light Microscope. Based on seed shape and surface ornamentation, seven morphological categories are recognized: cristate, tetracostate, foveolate, tumid tuberculate/cristate, circumalate, medusiform, and a miscellaneous category. Most sections and/or generic categories can be characterized by a single morphological type, althoughMaurandya s.l. has several distinctive seed types included within present generic boundaries. The cristate seed type is believed to be the “primitive type” from which the medusiform and tumid tuberculate/cristate types have developed. The tumid tuberculate/cristate type presumably gave rise to the circumalate, tetracostate, and foveolate patterns. The miscellaneous category (represented byLinaria andKickxia) may be phyletically remote from the other New World types. Seeds of the New WorldAntirrhineae mostly seem to be adapted for water dispersal although some adaptations for wind dispersal (e.g. wings, light weight) are evident. Free-hand sections and seed coat clearings indicate that circumalate seeds are of two different anatomical patterns; such structural diversity may be found in the other seed types.     

The potential in fluvial geomorphology of a new mineral identification technology (QEM*SEM)

The mineralogical signatures of fluvial sediments can be used to identify source areas and the degree of mixing of sediments from different fluvial and non-fluvial sources. The potential use of these signatures has not been fully realised because of uncertainties that result from mineralogical change as a result of sorting and weathering and the considerable time and expense involved in conventional optical mineral identification. A new quantitative mineral identification system QEM*SEM (Quantitative Evaluation of Materials by Scanning Electron Microscope), using an image analysis system with energy dispersive spectrometry and back scatter electron responses to identify phases, has been employed to provide rapid and economic analysis of sediments; large numbers of grains are counted with a greater statistical reliability than was previously possible.Results from a survey at the Nepean River, NSW, delineate the maximum level of flooding in an environment where clearly defined flood deposits are not evident. The results suggest the flood levels to be higher than predicted from previous studies.     

Spermiogenesis in the brush-tailed possum,Trichosurus vulpecula (Marsupialia)

Summary Acrosome development in the Australian Brush-tailed possum, Trichosurus vulpecula, displays a number of extraordinary features. This is particularly evident in the later stages of spermiogenesis, when the area of the nuclear surface bounded by the nuclear ring, and covered by the acrosome, is reduced considerable. As a result, the acrosomal material becomes located over its definitive position on the anterior third of the dorsal nuclear surface; in this process it is thrown into a series of folds, and a wide subacrosomal space is formed.Further changes around the time of spermiation result in the release of a spermatozoon in which a thin layer of acrosomal material is closely applied to the nucleus over the area of the definitive location of the acrosome, whilst its margins are greatly extended and project freely away from the nucleus. The latter feature does not appear to have been reported for the sperm of other mammals.The authors would like to thank Dr. D.J.H. Cockayne, Director of the Electron Microscope Unit, University of Sydney, for the generous provision of transmission electron microscope facilities, and Dr. M.R. Dickson, Electron Microscopist in charge, Biomedical Electron Microscope Unit, University of New South Wales, for the use of other facilities. Also, thanks are due to Miss Robin Arnold and Mrs. Eva Vassak of the Department of Histology and Embryology, University of Sydney, for their expert assistance. The assistance of the N.S.W. National Parks and Wildlife Service in the provision of permits to work on these native mammals is acknowledged     

超高灵敏度荧光显微成像技术对光敏剂细胞内分布的初步研究

目的：探讨应用基于ICCD的超高灵敏度荧光显微成像系统研究光敏剂细胞内分布的可行性。方法：传代培养内皮细胞、食管癌细胞和肺癌细胞,将不同浓度血卟啉单甲醚(HMME)与细胞共同孵育不同时间。采用荧光显微镜及ICCD组成的荧光显微成像系统采集不同浓度及不同孵育时间条件下HMME的荧光图像,并采用计算机图像处理技术进行图像增强、滤波后计算其细胞浆与细胞核的平均荧光强度比值。同时应用激光共聚焦显微镜图像采集进行对比。结果：HMME浓度为5μg／ml时,荧光显微镜采集到HMME的荧光图像;HMME浓度升高到160μg／ml,激光共聚焦显微镜获得HMME的荧光图像。两组图像的特点都为胞浆中荧光强度较高,细胞核区荧光较弱;细胞浆与细胞核的比值约为2～3：1。结论：荧光显微镜和ICCD采集细胞内光敏剂的荧光图像灵敏度高,方法可靠、实用。HMME较多分布在细胞质中,细胞核吸收较少。     

An improved method for preparing microorganism laden alginate bead specimens for accurate Scanning Electron Microscope examination

Summary The distribution of biomass encapsulated within alginate beads can be examined using a Scanning Electron Microscope (SEM). Existing methods for the preparation of suitable specimens are extremely time consuming, involving fixing of samples with glutaraldehyde, dehydrating with successive acetone washings and final drying using a critical point technique. These preparations are necessary to avoid significant specimen shrinkage, however, the resultant specimens are sometimes difficult to analyse using an SEM or light microscope. A reliable quick method has been developed where alginate specimens are directly mounted using a water based adhesive, then dried under controlled conditions. These specimens were found to be robust enough for SEM processing and gave true measurements of the original alginate beads including microorganism orientation.     

澳洲杨(大戟科)胚珠及其种子附属结构的个体发育研究

以澳洲杨的胚珠及其种子为材料,运用光学显微镜和电镜扫描的方法对其从胚珠发生直到种子成熟的个体发育过程和结构进行观察,同时与鸭脚西番莲的种子附属结构的发育过程进行对比研究。结果表明:(1)澳洲杨的珠孔类型为外珠孔类型,种子附属结构起源于珠孔而非珠柄,其为种阜,而非假种皮。(2)鸭脚西番莲的珠孔类型为内珠孔类型,种子附属结构起源于珠柄,并且最终将珠孔包被,其为真正的假种皮结构。通过种阜与假种皮的不同个体发育过程,建立了大戟科种阜与假种皮的不同发育模式,并对种子附属结构的生物学功能及其暗示的不同植物进化路径进行了讨论。     

苹果四倍体品种天星的花粉形态及胚囊发育特征研究

利用扫描电子显微镜(SEM)和激光扫描共聚焦显微镜( LSCM)技术对二倍体富士苹果及其四倍体芽变品种天星的花粉性状及胚胎发育特征进行了观察与研究,结果表明:四倍体天星品种的畸形花粉率为10.27％,明显高于富士,花粉萌发率低,为62.42％.2个品种的花粉粒大部分侧面观为长椭圆形,具3沟型萌发孔沟,两极端形状宽而平整,极面观为三角形,但四倍体天星的花粉粒的极轴长和赤道轴长均大于二倍体富士,但P/E值小,差异显著,其花粉粒形状不及二倍体富士规则且饱满程度也低.四倍体天星的花粉表面为纵向条状纹饰,有少量分叉和穿孔,花粉外壁略显粗糙,不如二倍体富士的外壁光滑.天星和富士均为蓼型胚囊,二者均存在异常胚囊现象,天星的异常胚囊现象包括极核位置异常、极核数目异常、卵器结构异常、胚囊内有多个发育滞后的细胞等;而在富士中仅发现少数胚囊结构不完整的现象.     

Biology Coupling Characteristics of Mole Crickets' Soil-Engaging Components

Mole cricket (Gryllotalpa orientalis) is a typical animal living under ground. The soil-engaging components of mole cricket have the capacity of wear resistance against soil. In this paper, the foreleg, tergum and forewing of mole cricket were chosen as soil-engaging components and were observed by stereomicroscope (SM), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). The functions of the components were analyzed from the viewpoints of both entomology and bionics. The factors for function realization were found, and the single effect and coupling effect of these factors were investigated. Results show that the wear resistance characteristic of mole cricket is realized by biology coupling. The research of biology coupling provides a foundation to the technology of bionic coupling.     

Axonal protrusions in the small multiple endings in the extraocular muscles of the rat

Summary A special type of myoneural junction has been observed in the extraocular muscles of the rat with electron microscopy. These axon terminals are derived from unmyelinated nerves and contain synaptic vesicles and mitochondria. The terminals are invested by teloglia cells and separated by a synaptic cleft of about 500 Å from a slow-type muscle fibre. From the nerve ending a pseudopod-like evagination projects into the muscle cell. The membranes of this evagination and the muscle cells are only separated by a narrow cleft of about 100 Å, which is devoid of the basement membrane-like material typical of ordinary myoneural junctions. The evagination contains fewer axonal vesicles than other regions of the terminal axoplasm and the postsynaptic part of the muscle plasma membrane in this special region does not exhibit the postsynaptic thickening characteristic of ordinary myoneural junctions.The author thanks ProfessorAntti Telkkä, M.D., Head of the Electron Microscope Laboratory, University of Helsinki, for permission to use the facilities of the laboratory.