1,721,116 research outputs found
Plant biosystems
No full textAims and scope
Plant Biosystems is the research journal edited by the Società Botanica Italiana. Published six times a year, the journal is open to papers dealing with all aspects of plant biology, systematics, and ecology. Research studies containing novel and significant findings, from the molecular level to ecosystems and from micro-organisms to flowering plants, are welcome. Plant Biosystems succeeded " Giornale Botanico Italiano", the historical journal of the Società Botanica Italiana, from the year 1997.
Plant Biosystems has been conceived in consideration of the recent progress in botanical research. An editorial board has been devised to ensure that all the main trends of contemporary plant science are represented. Manuscripts are classified as 'Full Paper', 'Rapid Report' or 'Short Communication'. A Rapid Report is intended for publication, in a concise form, of new and relevant findings. The classification as Rapid Report is determined by the Editor. A Short Communication (no more than two printed pages) is for a concise but independent report. It is not intended for publication of preliminary results. Review articles are also published, but only upon invitation by the Editor. An international panel of highly qualified referees warrants the highest scientific standard
Analisi ultrastrutturale degli effetti della monensina in Euglena gracilis, con particolare riguardo all'apparato di Golgi
No full textUltraslructural analysis of the effects of monensin in Euglena gracilis, with special reference to the Golgi apparatus. - The monovalent ionophore, monensin, is known to affect the mature (trans) half of the dictyosomes of several organisms, including Euglena gracilis. We demonstrated that the exposure to high concentrations of this compound (2.5 x 10-5 to 10-4 M) provoked remarkable swelling also in the forming (cis) half of Euglena cisternae. Additional dilations affected the thylakoids of both mature chloroplasts and proplastids of greening cells in which the organelle development was slower than in the control group. No osmotic swelling was observed for the mitochondria. Since monnesin exchanges one proton for each monovalent cation (Na+or K+) transported, it follows that an energy driven influx of H+is necessary to accumulate sufficient osmotically active ions in a membrane compartment. Thus it is possible that H+-ATPases are present on both forming and mature half of Etiglena dictyosomes. © Taylor & Francis Group, LLC
The effect of monensin on chitin synthesis in Candida albicans blastospores
No full textMonensin, a monovalent cation ionophore, was used to investigate some steps of the wall synthesis and morphogenesis in Candida albicans blastospores. In the presence of the drug, the pathogenic yeast developed enormous wall and septum thickenings that reacted intensely and specifically with wheat germ agglutinin and chitinase coupled to colloidal gold and fluorescein isothiocyanate. Therefore, the aberrant zones are interpreted as sites of chitin accumulation. The increased production of this homopolymer, also demonstrated by the chemical analysis of cell wall preparations, implies that monensin interferes in some way with the regulatory factors that normally control, in space and time, chitin synthetase activity
Effects of Congo red on wall synthesis and morphogenesis in Saccharomyces cerevisiae
No full textCongo red, a stain which prevents polyglycan microfibril assembly, was assayed on growing cells of Saccharomyces cerevisiae. In the presence of 0.25 mg/ml of the chemical, yeast developed aberrant wall thickenings and malformed septa, and underwent several budding events without the occurrence of the separation between mother and daughter cells. It is suggested that Congo red may uncouple polymerization and crystallization of the wall constituents, primarily chitin, that normally form microfibrils. It is also propsed that the regular assembly of the chains into microfibrils is needed to give a correct rate and direction to the process of polyglycan synthesis
Morphological anomalies induced by Congo red in Aspergillus niger
No full textAspergillus niger germ tubes were exposed for 6 h to 0.15 mg/ml of Congo red, a stain which prevents chitin microfibril assembly. The most evident alterations, detected under ultraviolet light and by transmission and scanning electron microscopy, concerned the hyphal tips which burst or, most frequently, expanded into bulges. In the latter structures, new hyphal tips appeared which, after giving rise to more or less developed hyphae, were themselves converted into new bulges. Therefore, segments derived from isotropic and polarized growth alternated in the organisms exposed to the dye.
An interpretation of these abnormalities is advanced based upon the assumption that the maintainance of a regular gradient of wall viscosity in the hyphal extension zone depends primarily on the capability of glycan chains to form crystalline aggregates of increasing complexity
Anomalous morphogenetic events in yeasts exposed to the polysaccharide-binding dye Congo red
No full textWhen exposed to Congo red, Rhodotorula glutinis halts cell proliferation, whereas Saccharomyces cerevisiae continues to bud; however, the separation between mother and daughter cells is impeded. Both yeasts develop diverse wall and septum abnormalities due to the accumulation of amorphous materials instead of chitin microfibrils. In Saccharomyces, the original wall frequently breaks and numerous vesicles, probably of secretory nature, are visible in the cytoplasm. The microorgamisms employed react differently to Congo red exposure due to the different roles that chitin plays in their walls. To explain why Congo red forces chitin synthase to form excessive amounts of N-acetylglucosamine chains with a random distribution, a model is proposed in which multienzyme complexes dissociate into single units since the polymers under synthesis, with the dye attached, can not assemble regularly. Each enzyme subunit continues to form glucan chains while it moves freely and randomly along the plasma membrane
Cytoskeletal structures in Euglena gracilis after Triton X-100 extraction and dry cleaving
No full textA three-dimensional network of structural filaments was visible with common electron microscopes in the cytoplasm of Euglena gracilis green cells extracted with buffers containing the nonionic detergent Triton X-100. A similar filamentous web was detected at the periphery of critical point dried cells cleaved on grids by means of an adhesive tape. SDS-polyacrylamide gel electrophoresis of the detergent-resistent cytoskeleton showed that actin or actin-like proteins of molecular weight in the range of 43–45 K are not among the components having a structural role inEuglena. The significance of these findings was discussed in relation to the capability of the alga to change the cell shape
Aberrant development of Trichophyton mentagrophytes hyphae cultured in the presence of Congo red
No full textWhen Trichophyton mentagrophytes colonies were placed on a medium containing 150 micrograms/ml of Congo red, a dye which prevents chitin fibrillogenesis, their growth rate was reduced. The newly formed mycelium, examined under an ultraviolet microscope, consisted of thick, curled and branched hyphae endowed with swollen tips and subapical bulges. Short-time exposure revealed that the major sites of dye accumulation were the extension zones. Normally structured hyphae arose from aberrant mycelia when they were transferred onto a dye-free medium. The phenomena observed suggest that Congo red alters the wall properties of the extension zone, by inhibiting the gradual conversion of chitin chains, synthesized at the extreme tip, into microfibrils of increasing size and density
Contact vulvitis due to Pseudowintera colorata in a topical herbal medicament.
No full texta case of allergic contact dermatitis due to pseudowintwra colorata in a topical medicament is reporte
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