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Functional morphology of Helix pomatia salivary gland cells was studied at light microscopic level by using different histochemical methods. Three cell types could be demonstrated in the salivary gland: mucocytes, granular and vacuolated cells. The distribution and the number of the different cell types were different in active and inactive snails. In active feeding animals, dilatated interlobular salivary ducts were observed, which were never present in inactive ones. In active animals an additional cell type, the cystic cell could also be observed. Periodic acid Schiff staining revealed both mucuos and serous elements in the salivary gland. Furthermore, hematoxyline-eosin staining indicated the occurrence of a cell layer with high mitotic activity in the acini. Applying immunohistochemical methods with monoclonal mouse anti-human Ki-67 clone, B56 and polyclonal rabbit anti-human Ki-67 antibodies, we also were able to demonstrate the occurrence of dividing cells in the salivary gland. Analysis of 1-2 µm semi-thin Araldite sections stained with toluidine-blue showed that the saliva can be released, in addition to possible exocytosis, by the lysis of cystic cells. Using an apoptosis kit, we could also establish that this process was due to rather an apoptotic than a necrotic mechanism. In the salivary gland of active snails, where an intensive salivation takes place, significantly more apoptotic cells occurred, if compared to that of inactive animals. It is suggested that programmed cell death may also be involved in the saliva release.
Theridion impressum is one of the dominant foliage dwelling spider species of maize fields in Hungary. Spider webs were collected from Bt and isogenic maize plots in three successive years. Captured insects in the web were identified. The most frequent prey items were aphids, plant hoppers and beetles. Although the number of captured insects in web samples from isogenic maize was slightly higher than those from Bt maize in the case of almost each insect order, except for two samples (Sternorrhyncha, 2001; Neuroptera, 2002), the differences between Bt and isogenic samples were not significant.
DSC studies on the polymorphism and pseudopolymorphism of pharmaceutical substances
A complex system for studying physico-chemical behaviour of binary mixtures
A complex system including thermoanalytical methods, infrared spectroscopy and X-ray powder diffraction for studying physico-chemical behaviour of binary mixtures is described. This system has been tested by investigating binary mixtures of amphetamine hydrochloride salts.
Benthic diatom investigations of some Hungarian streams have been carried out in order to find reference sites in assistance to the ecological quality analysis of the different river types according to the Hungarian river typology. On the basis of the coevaluation of biological and chemical parameters, among the investigated streams, some part of Kemence stream seems to be the appropriate reference site for the classification of the highland, siliceous rivers of Hungary. However, further invastigations are needed for the selection of reference sites for the other types of Hungarian river typology. This is the most difficult in the case of lowland rivers, which are exposed to more severe anthropogenic impacts. Important is the question which biological parameters should be investigated and considered when assessing the ecological condition of our waters. In the United States, e.g. the assessment of the relative abundance of Achnanthidium minutissimum is quite widespread (Stevenson and Bahls 1999), the extent of which indicates the level of disturbance. The use of this method is hampered, on one hand, by the fact that A. minutissimum is an early coloniser species which means that if we do not take samples from mature periphyton, we might find it dominant simply because of that, and, on the other hand, that distinguishing between the species varieties is not always unambiguous under light microscope because of its small size, and these can have different ecological needs. It is also recommended to calculate species richness, diversity and evenness (Stevenson and Bahls 1999), but based on our investigations these parameters are not in correlation with water quality. Investigation of other diatom features such as tolerance and sensitivity, some autecological parameters (as it was applied and recommended by Fore and Grafe 2002 for investigating the reaction of diatom associations to anthropogenic disturbances) might also be useful in completing the water quality analysis of rivers, however, these methods need further investigations. Some of the indices (EPI-D, IPS, IBD) calculated with the software Omnidia are suitable for the classification of our rivers, but the investigation of more rivers, flowing through different types of stone are necessary to choose the appropriate indices. The reason for this is that the different indices work with a different register of species and obviously those indices will prove to be suitable the species register of which shows the highest similarity to the diatom associations of the certain water type.
Komárek, J. and Anagnostidis, K. (2005): Cyanoprokaryota. 2. Teil: Oscillatoriales. - In: Büdel, B., Krienitz, L., Gärtner, G. and Schagerl, M. (eds): Süßwasserflora von Mitteleuropa, Band 19/2. Spektrum Akademischer Verlag, Elsevier GmbH, München, 759 pp.; Ross, I. A. (2005): Medicinal plants of the world - chemical constituents, traditional and modern medicinal uses. Volume 3. - Humana Press, Totowa, New Jersey, 623 pp. (ISBN 1-59259-887-0); Siver, P. A., Hamilton, P. B., Stachura-Suchoples, K. and Kociolek, J. P. (2005): Diatoms of North America: The freshwater flora of Cape Cod, Massachusetts, U.S.A. - In: Lange-Bertalot, H. (ed.): Iconographia Diatomologica. Annotated Diatom Micrographs. Vol. 14. A. R. G. Gantner Verlag K. G. Ruggel, 463 pp.;
The effect of reduction of pressure on the shapes of the TG, DTG and DTA curves and the mass-spectra of hydroxide and carbonate phases was investigated in some typical Hungarian red muds. The pressure change caused different decomposition rates of the phases and resulted in better separation of the overlapping thermal curves; this led to advantages as regards phase analysis. For phase analysis the red muds were extracted with water, and the extracts and solid residues were identified by IR- and X-ray methods.
The PC12 phaeochromocytoma cell line provides a useful model to study nerve growth factor-induced neuronal differentiation. The central signaling route of this process is mediated by the Ras-dependent extracellular signal-regulated kinase cascade. However, Ras-independent pathways are also stimulated by nerve growth factor and may contribute to differentiation signaling. One mediator for Ras-independent signal transduction in PC12 cells is phospholipase C-g that generates the second messengers diacylglycerol and inositol-trisphosphate. To probe the possible involvement of this enzyme in nerve growth factor-promoted differentiation, we used the phospholipase C inhibitor U73122 and the inositol-trisphosphate-receptor inhibitor Xestospongin C. Our results show that both chemicals block nerve growth factor-promoted neurite outgrowth, but the blockage of phospholipase C does not inhibit nerve growth factor-induced expression of c-fos, zif268 and transin genes. In addition, induction of these genes by nerve growth factor plus dibutyryl-cAMP is comparable in wild-type PC12 cells as well as in cells in which both Ras- and phospholipase C-g-mediated pathways are inhibited. The phospholipase C-g pathway thus belongs to those nerve growth factor receptor-originated signaling routes that contribute to the biological response of PC12 cells to nerve growth factor, but its gene activating potential does not have a major role in its neuritogenic effect.
