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Yeast submitochondrial particles, in a Pi- and NADH-dependent reaction, produced low concentrations of free ATP in the absence of added ADP. This formation of free ATP, as measured by the luciferin-luciferase method, was strongly stimulated by oligomycin. For maximal stimulation, oligomycin was to be added not earlier than 5–10 min after the addition of NADH. Upon addition of antimycin or FCCP the system was completely inhibited. The amount of free ATP formed corresponded to one-third of the amount of bound ATP in submitochondrial particles. The stimulatory effect of oligomycin disappeared if the submitochondrial particles were spun down after oligomycin stimulation and then resuspended in the reaction medium, whereas submitochondrial particles with no oligomycin added initially were stimulated by oligomycin after the same procedure. A different picture emerged with addition of ADP. If the submitochondrial particles were preenergized with NADH in the presence of oligomycin before the addition of ADP the formation of free ATP upon subsequent addition of ADP was inhibited by oligomycin. In the presence of oligomycin, but lacking preenergization with NADH, a stimulation of free ATP formation was achieved with added ADP. A possible explanation for the stimulating effect of oligomycin on ATP formation in the absence of added ADP is that it enhances the release of bound ATP in an energy-requiring process. The release of only about one-third of the bound ATP could indicate that one of three nucleotide-binding subunits involved in the mechanism of ATP formation by ATP synthase is in a state suitable for such an energy-dependent release of ATP. 相似文献
14.
Lucia Lioi 《Biologia Plantarum》1987,29(1):49-53
Relationships among storage proteins in seeds from cultivars and primitive accessions of the four economically most important
species ofPhaseolus — P. vulgaris, P. coccineus, P. acutifolius andP. lunatus — were studied.
Analysis of SDS-polyacrylamide gel electrophoretic patterns of storage seed proteins revealed common characteristics in the
major groups of polypeptides forP. vulgaris, P. coccineus andP. acutifolius, while clear differences existed between thesePhaseolus species and P.lunatus. 相似文献
15.
Growth curves,morphology and ultrastructure of ten Paracoccidioides brasiliensis isolates 总被引:1,自引:1,他引:0
Suely Sanae Kashino Vera Lucia Garcia Calich Lucia Mary Singer-Vermes Paulo Alexandre Abrahamsohn Eva Burger 《Mycopathologia》1987,99(2):119-128
The yeast phase of ten P. brasiliensis isolates were studied to characterize their growth pattern, morphology and ultrastructure. Growth curves were determined after counts of total and viable fungi units (FU) during 20 days. Three growth patterns were observed: slow, reaching approximately 10–30× 106 FU/tube (Pb 18, Pb 265 and PB 2); intermediate, reaching 60–150×106 FU/tube (IVIC Pb 9, IVIC Pb 267, Pb SN, Pb Vitor and Pb Campo Grande) and fast, reaching 180–370×106 FU/tube (Pb 2052 and Pb 192). The highest percentage of viable cells occurred on the 6th day of culture for Pb 192, Pb Campo Grande, Pb 2052 and IVIC Pb 9; on the 8th day for Pb Vitor, Pb SN, Pb 18 and IVIC Pb 267; on the 10th day for Pb 265 and on the 12th day of culture for Pb 2. Mean generation times varied from approximately 21.2 (Pb 2052) to 102.6 hours (Pb 265). The isolates showed similar morphology, except IVIC Pb 267 which did not present a typical yeast-phase at 35°C and the two fast-growing isolates (Pb 2052 and Pb 192) that presented smaller cell sizes and less tendency to clump. The ultrastructure of the isolates was similar: the cell walls presented a width of 0.1 to 0.2 °; the mitochondria presented few cristae and had equivalent patterns of distribution and morphology; the endoplasmic reticulum was scanty, presenting narrow cisternae; the vacuoles, empty or filled with electrondense material, were numerous and two to five nuclei with pores were constantly observed. 相似文献
16.
F Majone L Busulini A Capozzi N Bianco D Saggioro A G Levis F Bordin 《Mutation research》1989,227(1):17-20
We studied the DNA replicon size in BALB/c and BALB/Mo mouse lymphocytes by the method of bromodeoxyuridine photolysis. After treatment of the BALB/Mo lymphocytes in vitro with mitomycin C, the average DNA replicon size appeared to be significantly smaller than that observed in BALB/c lymphocytes treated similarly. In these conditions an increased susceptibility to SCE induction in BALB/Mo lymphocytes had been observed. In the presence of both mitomycin C and cordycepin (an antiviral drug), both the DNA replicon size and the SCE frequency returned to normal values. 相似文献
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Specific immune regulation of chronic-relapsing experimental allergic encephalomyelitis in mice 总被引:4,自引:0,他引:4
M K Kennedy M C Dal Canto J L Trotter S D Miller 《Journal of immunology (Baltimore, Md. : 1950)》1988,141(9):2986-2993
These studies were designed to examine immunologic means of regulating the clinical course of murine chronic-relapsing experimental allergic encephalomyelitis (R-EAE). We asked whether induction of specific immune tolerance to the major CNS myelin proteins, myelin basic protein (MBP) and proteolipid protein (PLP), could inhibit the development of R-EAE. Neuroantigen-specific tolerance was induced in SJL/J mice in a dose-dependent manner by the i.v. injection of mouse spinal cord homogenate-coupled syngeneic splenocytes (MSCH-SP) on day -7 relative to immunization on days 0 and +7. Sham-tolerized controls developed significant MBP- and PLP-specific DTH responses before the onset of clinical R-EAE. In contrast, MSCH-SP tolerized mice exhibited a dramatically reduced incidence of clinical and histologic signs of disease which correlated with the failure to develop MBP- and PLP-specific DTH responses. In 10 separate experiments, 118/149 (79%) of control mice, but only 22/137 (16%) of tolerized mice developed clinical R-EAE. Tolerance took time to develop and lasted at least 4 wk as mice injected with Ag-coupled splenocytes on day -1 relative to immunization remained susceptible to R-EAE, whereas mice injected on days -7, -14, or -28 were resistant. Tolerance induction required neuroantigens as injection of splenocytes coupled with a syngeneic mouse kidney homogenate failed to significantly alter the incidence of R-EAE or the development of neuroantigen-specific DTH responses. Thus, induction of R-EAE can be specifically and significantly regulated after the i.v. injection of splenocytes coupled with a crude, heterogeneous mixture of neuroantigens (i.e. MSCH). 相似文献
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L. Vitellaro-Zuccarello R. Garbelli V. Dal Pozzo Rossi 《Cell and tissue research》1992,268(3):505-511
Summary The distribution of collagen types I, III, IV, and of fibronectin has been studied in the human dermis by light and electron-microscopic immunocytochemistry, using affinity purified primary antibodies and tetramethylrhodamine isothiocyanate-conjugated secondary antibodies. Type I collagen was present in all collagen fibers of both papillary and reticular dermis, but collagen fibrils, which could be resolved as discrete entities, were labeled with different intensity. Type III collagen codistributed with type I in the collagen fibers, besides being concentrated around blood vessels and skin appendages. Coexistence of type I and type III collagens in the collagen fibrils of the whole dermis was confirmed by ultrastructural double-labelling experiments using colloidal immunogold as a probe. Type IV collagen was detected in all basement membranes. Fibronectin was distributed in patches among collagen fibers and was associated with all basement membranes, while a weaker positive reaction was observed in collagen fibers. Ageing caused the thinning of collagen fibers, chiefly in the recticular dermis. The labeling pattern of both type I and III collagens did not change in skin samples from patients of up to 79 years of age, but immunoreactivity for type III collagen increased in comparison to younger skins. A loss of fibronectin, likely related to the decreased morphogenetic activity of tissues, was observed with age. 相似文献