Ontogeny of elastoviscin in the Orchidaceae

The ontogeny of elastoviscin in the Orchidaceae was investigated with the light, transmission electron and scanning electron microscope. This substance is composed of unsaturated lipids and most probably a product of the ground cytoplasm of the tapetal cells. Different forms of elastoviscin are described. Further investigations are needed to determine whether it is homologous to pollenkitt.     

In situ flat embedding of monolayers and cell relocation in the acrylic resin LR White for comparative light and electron microscopy studies

Summary A simple and reliable method has been developed for the in situ LR White embedding of cell monolayers grown on glass cover-slips. Combined with cytochemical or immunological procedures, this technique allows light and/or electron microscopy investigations of a large number of cells in the same horizontal plane within a relatively short period of time. It can be applied to cells grown on microgrid finder cover-slips which allows a distinct site of even an individual cell of a monolayer to be studied at first at the light microscope level and subsequently at the electron microscope level. Hence, it is also suitable for controlling manipulation of single cells, followed by their serial sectioning after relocation in the electron microscope.     

Ultrastructural changes in dermal melanophores in the process of pigment granule migration

The results of electron microscope investigations on dermal melanophores of Rana temporaria L. during migration of pigment granules are presented. It was shown that in comparison to the previous observations dermal melanophores are flat cells without branches. Ultrastructural differences have been demonstrated in dermal melanophores during migration of pigment granules. During melanosome dispersion membrane vesicle bodies are seen in the cytoplasm to be inserted in the melanophore membrane.     

Flax processing in the Neolithic and Bronze Age pile-dwelling settlements of eastern Switzerland

Numerous artefacts from the area of textile production as well as finished products, fabrics and netting, dating from the period between 3900 and 800 b.c. have survived in the archaeological layers of late Neolithic and Bronze Age wetland settlements in eastern Switzerland. Archaeological investigations, experiments in textile technology and comparisons with Egyptian wall paintings, as well as analyses under the scanning electron microscope, allow us to almost completely reconstruct Neolithic textile production in prehistoric pile dwellings.     

Elastic fibers in the tunica propria of the seminiferous tubules. Light and electron microscopic investigations.

Histological examination of numerous biopsies from mature testes, repeatedly showed irregularities of the elastin staining in the tunica propria of the seminiferous tubules. Even when abundant elastic fibers were visible by light microscopy, no elastic fibers were demonstrable in the electron microscope in ultrathin sections of testicular tubules embedded in Epon and contrasted with phosphotungstic acid (PTA). In 43 biopsies from 22 men aged 17-39 years (19 investigations of sterility and three patients with hypogonadotropic hypogonadism) we therefore checked for the occurrence of elastic fibers in the wall of the seminiferous tubules. Matrix loci of elastic fibers could indeed by demonstrated by electron microscopy using PTA and potassium permanganate (KMnO4), but only after embedding in araldite. Under these conditions, light and electron microscopic findings agreed with each other. The appearances of moderate and severe testicular tubular atrophy differed slightly from one another with regard to the amount of elastin. In the "Sertoli cells only syndrome", elastic fibers were demonstrable only outside the hyalinized inner layer. In the Klinefelter syndrome, only "uncertain" elastin loci were present, but greatly increased microfibrils were to be seen using the electron microscope. No elastic elements and only very sparse microfibrils were present in the tunica propria of the tubules of young men with hypogonadotropic hypogonadism.     

Cytological characteristics of erythropoiesis in thalassemia. II. Structural functional characteristics of peripheral blood erythrocytes

In 61 patients affected with thalassaemia of various degrees of seriousness, cytological investigations were carried out on erythrocytes in the peripheral blood. The interferometrically determined changes in the dry mass of erythrocytes, the diminution of the surface potential expressed in electrophoresis, the changes in the membrane structure of erythrocytes which could be represented in the scanner electron microscope were directly dependent on the seriousness of the disease.     

Further observations on the type species of Pyramimonas (P. Tetrarhynchus Schmarda) (Prasinophyceae): an examination by light microscopy, together with notes on its taxonomy

Previous records of Pyramimonas tetrarhynchus are examined, and a morphological variant is designated as var.lobata var.nov.
The species was studied by light microscopy using cultured material, as a supplement to investigations with the electron microscope published separately. Particular attention was paid to aspects of cell symmetry at various stages of division.     

TRICOMPLEX FIXATION OF PHOSPHOLIPIDS

A basis for the interpretation of the structure of the cell membrane is often looked for in electron microscope investigations on the structure of lipid models. A difficulty in these investigations is our lack of knowledge of the effect of the preparative treatment on the structure studied. This applies especially to the strongly oxidizing fixatives: osmium tetroxide and potassium permanganate. These agents have, moreover, the drawback that they cannot be used to fix fully saturated lipids. On the basis of existing theories concerning complex colloid systems, a fixation method was developed that allows the electron microscope study of the structure of phospholipid models, irrespective of whether they consist of saturated or unsaturated compounds. With this fixation, namely tricomplex flocculation by means of suitable ions, the structure of the lipid molecules is not altered. Moreover, the site and mode of action of this fixation are well known. The first application of this method to the study of isolated beef brain phospholipids is described.     

Fine structure of diffused pseudobranchial neurosecretory cells associated with carotid labyrinth in an air‐breathing catfish Clarias batrachus

Fish are known to have branchial chemoreceptors and even extrabranchial chemoreceptors to meet the challenges of aquatic environment. The pseudobranchial neurosecretory system associated with carotid labyrinth (CL) is one such example. CL – a chemosensory organ is well known in amphibians. The homologous structure also exists in fish. Clusters of neurosecretory cells, close to the CL and the first two efferent branchial arteries occur in catfish and a few other groups of teleosts. These cells belong to the pseudobranchial neurosecretory system (PNS). To reveal the ultrastructure of CL and the pseudobranchial neurosecretory cells (PNSCs), environmental scanning electron microscope (ESEM) and transmission electron microscope (TEM) investigations were made in an Asian air‐breathing catfish Clarias batrachus. Under ESEM, the PNS appeared as a mass of cells innervated by nerves and supplied by blood capillaries. The CL appeared to have a network of blood capillaries. The transmission electron microscopic investigations showed pear shaped PNSCs having different sizes of dense cored vesicles (DCVs), numerous mitochondria, nerve varicosities, indicating a secretory function of the cells. The CL shows a close association with PNSCs and smooth muscles. Although the exact function of the CL and associated PNSCs in the biology of fish is far from clear, their morphology suggests they are involved in a stress response such as to hypoxia.     

The postnatal development of capillaries in the triceps muscle of arm of the white rat. Light and electron microscopic studies]

This paper continues former ultrastructural investigations about fetal development of capillaries in the muscle anlage of the fore limb of white rats. Present investigations deal with postnatal ultrastructural changes of the capillaries of the triceps muscle of rats from the 4th up to the 23rd day p.p. Counting of the capillaries with light and electron microscope reveal a linear increase of the capillary to fiber ratio in this period proportional to the growth of the muscle. Related to a defined area however the number of capillaries remains constantly. Ultrastructural changes of capillaries consist in further flattening of the endothelial profiles, decrease in number or organelles (mitochondria and endoplasmic reticulum), while the number of pinocytotic vesicles remains highmthe endothelial joints become less interdigitated, the basement membrane shows an increase in density leading to a temporary decrease in thickness. Since the 9th postnatal day all of the capillaries including buds closely border upon the muscle fibres. The distance between endothelium and myofiber diminishes up to 0,1 mum.     

Improvement of the morphometry method and its use in electron microscopic studies

The paper describes morphometric device for electron microscope. Using this gauge one can get morphometric data from the screen of the electron microscope. Perspectives of morphometric analysis of ultra-structures in the electron microscope are discussed.     

Hierarchical structural comparisons of bones from wild-type and liliput(dtc232) gene-mutated Zebrafish

The alterations of hierarchical structures of bone by gene mutation in the zebrafish, which is associated with abnormal bone mineralization and bone disease, were reported for the first time in this paper. Bone samples from the liliput(dtc232) (lil) mutants as well as normal controls were studied by polarized light microscope, scanning electron microscope (SEM), transmission electron microscope (TEM), and atomic force microscope (AFM). Light microscopy examinations reveal that the lil bone has asymmetric mineralization and much thinner bone wall. The SEM studies show a lot of microcracks in lil bone wall. And the plywood-like structure of the normal bone does not exist in the lil bone, which is confirmed by the measurements of polarized light microscope. Furthermore, the TEM investigations display the collagen fibrils with two typical diameters. For the thinner collagen fibrils, the diameter of lil bone is about twice larger than that of the wild-type bone. And for the thicker one, there is a small increase in diameter after mutation and the band periodicity of the lil bone is similar with that of wild-type bone, which is consistent with the result of AFM. The morphologies of the minerals revealed that the mutated mineral was in bigger size and the shape was irregular but not plate-shaped.     

Preparation of hybrid antibodies with mouse IgG and ferritin specifities for the immune electron microscopic detection of cell membrane antigens]

Use of hybrid antibodies with one specifity for mouse-IgG and the other one for ferritin is particularly suitable for immune electron microscopical detection of cell surface antigens. Preparation of antibodies of such kind is described, whereby the method introduced by HMMERLING et al. is varied within some steps of preparation. These variations are discussed here. Activity of produced hybrid antibodies is demonstrated by labeling the THY 1.1. antigen on the cell surface of the thymocytes of the mouse. The advantages of utilizing the hybrid antibodies in comparison with known immune electron microscopical techniques are an excellent location of the antigens, the possibility of using distinct particles for labeling, the application of a multiple labeling, and the fact that investigations by both the transmission and the scanning electron microscope can be carried out by means of the same preparation of hybrid antibodies.     

Simultaneous Correlative Scanning Electron and High-NA Fluorescence Microscopy

Correlative light and electron microscopy (CLEM) is a unique method for investigating biological structure-function relations. With CLEM protein distributions visualized in fluorescence can be mapped onto the cellular ultrastructure measured with electron microscopy. Widespread application of correlative microscopy is hampered by elaborate experimental procedures related foremost to retrieving regions of interest in both modalities and/or compromises in integrated approaches. We present a novel approach to correlative microscopy, in which a high numerical aperture epi-fluorescence microscope and a scanning electron microscope illuminate the same area of a sample at the same time. This removes the need for retrieval of regions of interest leading to a drastic reduction of inspection times and the possibility for quantitative investigations of large areas and datasets with correlative microscopy. We demonstrate Simultaneous CLEM (SCLEM) analyzing cell-cell connections and membrane protrusions in whole uncoated colon adenocarcinoma cell line cells stained for actin and cortactin with AlexaFluor488. SCLEM imaging of coverglass-mounted tissue sections with both electron-dense and fluorescence staining is also shown.     

Nano-channels in the spider fang for the transport of Zn ions to cross-link His-rich proteins pre-deposited in the cuticle matrix

We identify the presence of multiple vascular channels within the spider fang. These channels seem to serve the transport of zinc to the tip of the fang to cross-link the protein matrix by binding to histidine residues. According to amino acid and elemental analysis of fangs extracted shortly after ecdysis, His-rich proteins are deposited before Zn is incorporated into the cuticle. Microscopic and spectroscopic investigations in the electron microscope and synchrotron radiation experiments suggest that Zn ions are transported through these channels in a liable (yet unidentified) form, and then form stable complexes upon His binding. The resulting cross-linking through the Zn–His complexes is conferring hardness to the fang. Our observations of nano-channels serving the Zn-transport within the His-rich protein matrix of the fibre reinforced spider fang may also support recent bio-inspired attempts to design artificial polymeric vascular materials for self-healing and in-situ curing.     

The X-ray microanalysis method for investigation of chemical composition of normal and pathologic human peripheral blood lymphocytes

The X-ray microanalysis method for investigation of chemical composition, mainly trace elements, of normal and pathologic human peripheral blood lymphocytes has been presented. The method in question consists of two stages. During the first stage the scanning electron microscope with the energy dispersive X-ray spectrometer has been used. The second stage of the method consisted of employing the above microscope with the microwave dispersive spectrometer. The method enables the short-term determination of the various elements content within the lymphocytes with particular insight into the content of elements in a single cell. The preliminary investigations showed significant differences in the content of chlorine, sulfur and lead in normal human lymphocytes and that from patients with cancer of the larynx.     

An electron microscopic study of antagonism between cephalexin and erythromycin in Staphylococcus aureus.

This study concerns investigations at the cellular level of antagonism between cephalexin (CEX) and erythromycin (EM) with the aid of electron microscopes and a liquid scintillation counter. Exposure of Staphylococcus aureus 209-P to CEX and EM in combination was found to result in a marked antagonism between the two antibiotics in their effects on the growth of the organism. Observations under a scanning electron microscope revealed lysed cells in the presence of CEX alone but almost no lysis in the presence of a combination of CEX and EM. Observations under a transmission electron microscope, on the other hand, disclosed that nearly all of the cells exposed to 20 mug/ml of CEX were transformed into protoplasts with their morphological changes being most marked after 4 hr of exposure. When 1 mug/ml of EM was allowed to act alone, this exposure resulted in thickening of the cell walls. The combined use of CEX and EM, however, resulted in neither thickening of the cell walls as in the presence of EM alone nor in the formation of protoplasts as in the presence of CEX alone but merely produced the swelling of separating walls. Cellular uptake of 14C-L-lysine and N-acetylglucosamine-1-14C into the cell wall fraction and the protein fraction was affected by CEX and EM, respectively, when used alone or in combination.     

About the T-system in the myofibril-free sarcoplasm of the frog muscle fibre

Previous investigations of the T-system in skeletal muscle fibres described the inter-myofibrillar relationships between T-tubules and the sarcoplasmic reticulum. They disregarded the arrangement of the T-system in the myofibril-free sarcoplasm in the area of muscle fibre nuclei. In the present investigation, the T-system was filled by means of lanthanum incubation and the myofibril-free sarcoplasm was ultrastructural examined by means of thin (< or = 100 nm) as well as thick sections (> 300 nm-1 microm) with the electron microscope. The investigation of thick sections revealed that T-tubules meander through this myofibril-free sarcoplasm and tangle up at the poles of muscle fibre nuclei and in the area of fundamental nuclei of the motor end plate. They are, far from myofibrils, in proximity to these nuclei, the Golgi apparatus and mitochondria. On basis of this proximity and their openings at the muscle fibre surface, a contribution at the drainage of metabolic products and at the local calcium control is discussed.