This work aims to investigate the origins and development of secretory cells in Piper umbellatum (L.) Miq. (Piperaceae) leaves as well as the course and the nature of their secretion. The results were compared with studies in oil-secreting cells of several species. Fully expanded fresh leaves were sectioned and subjected to different histochemical tests. Leaves in different developmental stages were fixed and processed for study under light and scanning and transmission electron microscopy techniques. The secretory cells show mixed secretion made up of hydrophobic (oleoresin) and hydrophilic (phenolic compounds and alkaloids) compounds. Secretory cells originate either from the protodermis or the ground meristem. The growth of these cells occurs primarily by increasing the volume of the central vacuole, which corresponds to an extraplasmatic space connected to a protuberance of the wall. Electron-opaque compounds are observed initially in leucoplasts, while electron-dense compounds occur in small vesicles in the cytoplasm. Both are accumulated in the central vacuole which is already developed. Besides the mixed chemical nature of the secretion identified in secretory cells of P. umbellatum leaves, these secretory cells differ from those that have already been described mainly because of the development of the central vacuole prior to the accumulation of the secretion. 相似文献
The historical circumstances that led to the discovery of the 3,3′-diamino-benzidine (DAB) method for staining of peroxisomes
40 years ago are reviewed. In the course of studies on the uptake and absorption of horse radish peroxidase in mammalian liver,
in sections incubated for detection of peroxidase activity in DAB, it was noted that peroxisomes also stained positively for
peroxidase activity. Subsequently, it was revealed that the peroxidatic activity of catalase, which is abundantly present
in peroxisomes, is responsible for that staining. This notion was confirmed in quantitative biochemical studies with crystalline
beef liver catalase and in tracer studies using catalase as an ultrastructural tracer. The application of the DAB method led
to the discovery of peroxisomes as a ubiquitous eukaryotic cell organelle, attracting great interest in their investigation
in biomedical research. 相似文献
The variability of fiber type distribution in nine limb muscles was examined with histochemical and tensiomyographical (TMG) methods in two groups of 15 men aged between 17 and 40 years. The aim of this study was to determine the extent to which the relative occurrence of different fiber types and subtypes varies within human limb muscles in function to depth and to predict fiber type proportions with a non-invasive TMG method.
The distribution of different fiber types varied within the muscles, as a function of depth, with a predominance of type 2b fibers at the surface and type 1 fibers in deeper regions of the muscle. For all the analyzed muscles the contraction times measured at stimulus intensity 10% of supramaximal stimulus (10% MS) were significantly (p<0.05) shorter than the contraction times measured at 50% of supramaximal stimulus intensity (50% MS). The Pearson's correlation coefficient between percentage of type 1 muscle fibers measured at the surface of the muscle and contraction time at 10% MS, obtained by TMG was statistically significant (r=0.76,P<0.01). Also the Pearson's correlation coefficient between percentage of type 1 muscle fibers measured in the deep region of the muscle and contraction time at 50% MS obtained by TMG was also statistically significant (r=0.90,P<0.001).
These findings suggest that the contraction time obtained by TMG may be useful for non-invasive examining of muscle fiber types spatial distribution in humans. 相似文献
The fig (Ficus L.) infructescence, called syconium, is a receptacle with an apical opening, the ostiole, closed by bracts. The ostiolar bracts produce an exudate, which is rather conspicuous in some species. It has not been histochemically analyzed yet, and the structures responsible for its production are still unknown. Some wild growing species of Ficus from Brazil produce high amounts of this ostiolar exudate. Ficus enormis (Mart. ex Miq.) Miq. grows as trees or shrubs in the Atlantic rainforest. Our goal was to identify the secretory structures present in the inflorescence and, to characterize histochemically the ostiolar tissues and exudates. Syconia samples of F. enormis were processed and stained according to the usual techniques in plant anatomy. The morphological analysis revealed different types of bracts, one type specialized in secretion, another showing transitional characteristics between secretory and non-secreting bracts, and a third one being non-secreting. They are designated as secretory ostiolar bracts, transitional bracts and wall bracts. The floral bracteoles, digital-shaped colleters present in the ostiole, at the syconium axis and at the flower receptacle, were also analyzed. All have similar structure, like finger-shaped secretory trichomes. The colleters present among ostiolar bracts may contribute to production and composition of the ostiole exudate. 相似文献
Various species of the genus Phlomis have been reported to produce metabolites demonstrating significant pharmacological efficiency. In mature summer leaves of Phlomis fruticosa several secretory cells and structures were detected. A spectrum of compounds was localized histochemically within them. Calluses produced from leaf-cell cultures were histochemically investigated as well. Callus cells, although of low-differentiation, are synthetically active and produce various compounds. Many of them could be of pharmaceutical interest. 相似文献
Summary Fine structural and enzyme histochemical observations on ultimobranchial body and parathyroid gland of the caecilian Chthonerpeton are presented. The cell clusters and follicles of the ultimobranchial body consist mainly of granulated cells which are termed C-cells and obviously belong to the APUD cell series. In the larger follicles additional possibly exhausted degranulated cells and replacement cells occur. A rich supply of nerve fibres has been found in this gland. Frequently nerve terminals were observed to come into synaptic contact with the C-cells. Two categories of nerve fibres occur: a) fibres containing large polymorphic electron dense granules (probably purinergic fibres), b) fibres containing small electron transparent vesicles and a few electron dense granules (probably cholinergic fibres). The parathyroid gland consists of elongated cells (one cell type) poor in organelles and often containing fields of glycogen and lipid droplets. The cells are further characterized by fair amounts of lysosomal enzymes; they are interconnected by maculae adhaerentes and occludentes. No nerves and blood vessels have been found in the parathyroid gland of Chthonerpeton.
This study has been supported by the Deutsche Forschungsgemeinschaft We 380/5. 相似文献