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21.
The effect of rhamnolipid-biosurfactant produced by Pseudomonas sp. PS-17 on cell surface structures of Pseudomonas aeruginosa NBIMCC 1390 was studied. The results demonstrated that the rhamnolipid at concentrations below and above CMC provoked a multi-component response of the bacterial cells without affecting their growth and viability. Above CMC, the rhamnolipid caused reduction of total cellular LPS content of 22%, which can be associated with an increase in cell hydrophobicity to 31% adherence. The rhamnolipid-biosurfactant at concentration below CMC did not affect the LPS component of the bacterial outer membrane but caused changes in OMP composition of P. aeruginosa. Examination of the OMP profiles revealed that the amount of major proteins (Opr F, Opr D, Opr J and Opr M) markedly decreased. To our knowledge this is the first report on the rhamnolipid-biosurfactant interactions with bacterial cells showing changes in outer membrane proteins of P. aeruginosa. In both concentrations, the biosurfactant caused changes in cell surface morphology. The results indicate that the rhamnolipid-biosurfactant from Pseudomonas sp. PS-17 has a potential application in the relatively new field of biomedicine. 相似文献
22.
A simple and rapid procedure for determination of intracellular acid phosphatase activity without the need for disruption of cells is described. Candida lipolytica cell suspension was treated with 0.1% Triton X-100 for 30 min at room temperature and with intermittent shaking. The enzyme assay is carried out directly with the permeabilized cell suspension. Permeabilization of the yeast cells to p -nitrophenylphosphate by Triton X-100 provides almost 100% efficiency in determining the total acid phosphatase activity compared to results obtained with disrupted yeast cells. 相似文献
23.
Summary A and B cells in the pancreatic islets of cattle are interlaced with one another. The histochemical characteristics of the islet cells is similar to that of some other mammals. Series of differences are however detected concerning: the positive reaction for glucose-6-phosphatase in the A cells and in the epithelium of the excretory ducts, the simultaneous presence of alkaline phosphatase in the A and B cells, a higher contents of phospholipids in the B cells and a lack of histochemically provable zinc. These differences in the histochemistry of the pancreatic islets of cattle are in authors, opinion an expression of peculiarity of the species. 相似文献
24.
Karakashev Dimitar Galabova Danka Simeonov Ivan 《World journal of microbiology & biotechnology》2003,19(3):233-238
A rapid qualitative test is proposed for bacterial respiratory type based on 24 h culturing of bacteria in liquid medium supplemented with a redox indicator: methylene blue or resazurin. Five reference bacterial strains with definite respiratory type as well as nine bacterial isolates from a laboratory digester for methane fermentation were used. Results obtained showed that both indicators can be used for distinction of strict aerobes from other bacterial representatives with definite respiration. In addition, the resazurin is able to differentiate strict anaerobes from microaerophiles and other anaerobes. The main advantages of the methylene blue is that it is a cheap, easily accessible dye, wide-used in microbiological practice and the results obtained with it are more stable over time. It was also noticed that the test with both indicators gave reliable results for the bacterial respiration only when an inoculum up to 48 h old was used. 相似文献
25.
Summary The histological picuture of the Langerhans' islets in hamster pancreas is quite similar to that in white rat pancreas, i.e.
the B-cells are located in the middle of the islet, while the A-cells in its periphery. Very often the argyrophil cells (D-cells)
are located between the A- and B-cells forming a peculiar “barrier”.
The histochemical studies reveal differences between the endocrine tissue and exocrine parenchyma. In general, the islet cells
are richer in enzymes, as compared with the acini. The histochemical characteristic of hamster pancreas is closest to that
of white rat pancreas. Like in rat, alkaline phosphomonoesterase reaction is very strong in the A-cells, while G-6-P reaction
is negative. But, concerning zinc localization, there are differences between hamster and rat. Zinc reaction is very strong
in the peripheral A-cells in white rat pancreas, while in hamster this reaction is much stronger in the B-cells (the reaction
is negative in the A-cells).
The D-cells can not be differentiated from the other endocrine pancreatic cells by means of hystochemical studies.
But these studies permit certain conclusion on the possible role of the enzymes and substances investigated in cytophysiology
of the islet cells. 相似文献
26.