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31.
Stephanie Bringer-Meyer Marc Scollar Hermann Sahm 《Applied microbiology and biotechnology》1985,23(2):134-139
Summary A mutant ofZymomonas mobilis deficient in the utilization of fructose for growth and ethanol formation was shown to lack fructokinase activity. When grown in media which contained glucose+fructose or sucrose, both the mutant and wild type produced sorbitol in amounts up to 60 g·l-1, depending on the initial concentrations of sugars. Sorbitol formation was accompanied by an accumulation of acetaldehyde, gluconate, and acetoin. A ferricyanide-dependent sorbitol dehydrogenase could be localized in the cell membrane; it thus resembles the sorbitol dehydrogenase ofGluconobacter suboxydans. Neither a NAD(P)H dependent reduction of fructose nor a NAD(P) dependent dehydrogenation of sorbitol could be detected in cell-free extracts. The use of fructose-negative mutants ofZ. mobilis for the enrichment of fructose in glucose+fructose mixtures is discussed. 相似文献
32.
G Konwalinka C Peschel F Schmalzl H E Schaefer D Geissler G Schuler H Huber B Tomaschek R Odavic H Braunsteiner 《International journal of cell cloning》1985,3(6):367-387
Thirty-seven patients with chronic cytopenia were studied using a CFU-gm assay in agar. Cell proliferation was evaluated on days 2, 3, 5, 7, and 10 of incubation. Growth patterns were different in cultures of hematologically healthy persons versus patients with preleukemic syndrome (PL) and aplastic anemia (AA). Three types of PL syndrome and two types of AA (C1 and C2) were distinguished. Bone marrow dysfunction was evaluated further using cytochemistry and electron microscopy to morphologically study cell proliferation in vitro. Cytochemical staining performed in agar demonstrated well-defined maturation defects in myelopoietic precursor cells from the bone marrow of PL patients. Electron microscopic findings of Auer-body-like inclusions in "statu nascendi" in the vacuoles of preleukemic cells supported our results. PL patient groups at high risk for development of overt leukemia and patients with grave prognosis in AA were distinguished. Our results are relevant for the clinical diagnosis and prognosis of patients with cytopenia. 相似文献
33.
34.
The effect of fat feeding (100 g of cream) on the apoA-I isoproteins distribution has been analyzed by two-dimensional gel electrophoresis in the chylomicrons, VLDL, LDL, and HDL isolated from the thoracic duct lymph of patients undergoing lymph drainage for immunosuppression, Isoforms apoA-I3 and apoA-I4 are the most abundant apoA-I isoproteins in plasma lipoproteins as well as in lymph lipoproteins collected in the fasting state. Fat feeding, on the other hand, results in a marked change in the apoA-I isoform pattern in lymph chylomicrons and VLDL, with a significant increase in the relative concentration of the apoA-I1 isoform. As a result the total concentration of this isoprotein in the lymph increased. The data indicate that fat feeding is associated with major changes in the distribution of the apoA-I isoforms in the lymph (d less than 1.006 g/ml lipoproteins), which may be of significance in their plasma catabolism. 相似文献
35.
Jerry L. Phillips Stephanie Waddingham Deborah A. Spiva 《Biological trace element research》1983,5(1):47-53
Lymphocytes were obtained from two patients with paroxysmal nocturnal hemoglobinuria as well as from apparently healthy controls and from patients with acute lymphoblastic leukemia and chronic lymphocytic leukemia. Subsequently, several aspects of zinc metabolism were studied in vitro in short-term cultures of these lymphocytes in order to assess lymphocyte functional capacity. The results of mitogen stimulation and zinc uptake studies for lymphocytes from donors with paroxysmal nocturnal hemoglobinuria were similar to those obtained for leukemic lymphocytes. The results of studies to determine the inducibility of the low molecular weight zinc-binding protein, metallothionein, by zinc were complicated by the decrease in overall protein synthesis in lymphocytes from donors in the paroxysmal nocturnal hemoglobinuria. It is proposed that paroxysmal nocturnal hemoglobinuria is indeed a clonal disorder and the relationship between lymphocytes in this disorder and leukemic lymphocytes is discussed. 相似文献
36.
37.
Of 109 cases in England and Wales in which mycobacteria of the avian-Battey group were isolated from man 89 were considered genuine infections (including 32 with Mycobacterium avium) and six were doubtful. Almost half the significant cases were lung infections in men in dusty occupations, mostly coal miners with pneumoconiosis, and just over a quarter were non-pulmonary, mostly cervical adenitis in children. The prognosis in lung infections was serious, especially in the presence of pneumoconiosis. 相似文献
38.
Comparison of deuterated leucine, valine, and lysine in the measurement of human apolipoprotein A-I and B-100 kinetics 总被引:3,自引:0,他引:3
A H Lichtenstein J S Cohn D L Hachey J S Millar J M Ordovas E J Schaefer 《Journal of lipid research》1990,31(9):1693-1701
The production rates of apolipoprotein (apo)B-100 in very low density lipoprotein and in low density lipoprotein and apolipoprotein A-I in high density lipoprotein were determined using a primed-constant infusion of [5,5,5,-2H3]leucine, [4,4,4,-2H3]valine, and [6,6-2H2,1,2-13C2]lysine. The three stable isotope-labeled amino acids were administered simultaneously to determine whether absolute production rates calculated using a stochastic model were independent of the tracer species utilized. Three normolipidemic adult males were studied in the constantly fed state over a 15-h period. The absolute production rates of very low density lipoprotein apoB-100 were 11.4 +/- 5.8 (leucine), 11.2 +/- 6.8 (valine), and 11.1 +/- 5.4 (lysine) mg per kg per day (mean +/- SDM). The absolute production rates for low density lipoprotein apoB-100 were 8.0 +/- 4.7 (leucine), 7.5 +/- 3.8 (valine), and 7.5 +/- 4.2 (lysine) mg per kg per day. The absolute production rates for high density lipoprotein apoA-I were 9.7 +/- 0.2 (leucine), 9.4 +/- 1.7 (valine, and 9.1 +/- 1.3 (lysine) mg per kg per day. There were no statistically significant differences in absolute synthetic rates of the three apolipoproteins when the plateau isotopic enrichment values of very low density lipoprotein apoB-100 were used to define the isotopic enrichment of the intracellular precursor pool. Our data indicate that deuterated leucine, valine, or lysine provided similar results when used for the determination of apoA-I and apoB-100 absolute production rates within plasma lipoproteins as part of a primed-constant infusion protocol. 相似文献
39.
Lisette Waits Stephanie Dunkle F. E. Wilkinson P. Moreau Keri Safranski T. Reust Dorothy M. Morré D. J. Morré 《Protoplasma》1990,154(1):8-15
Summary Transfer of radiolabeled lipids from dictyosome-like structures (DLS) from testis tubules of the guinea pig as donor to unlabeled plasma membrane from testis tubules immobilized on nitrocellulose as acceptor was studied in a completely cell-free system. As a general label for lipids of the donor DLS, isolated testis tubules were incubated with [14C]acetate. Time- and temperature-dependent transfer of [14C]acetate labeled constituents was observed in the cellfree system. However, despite the fact that phospholipids and other constituents were highly labeled in the donor fraction, primarily radioactive sterols were transferred to the plasma membrane acceptor vesicles. Transfer at 37°C represented 0.4 to 0.7% of the total radiolabeled cholesterol at 37°C but little or no transfer occurred at 4°C. The sterols transferred exhibited Chromatographic mobilities corresponding to those of cholesterol and lanosterol. Similar results were obtained with [14C]mevalonic acid. In subsequent experiments, cholesterol transfer from DLS to plasma membrane was demonstrated by incubation of DLS with [3H]squalene which was converted into sterol or with [14C]cholesterol. Transfer of sterols required ATP, but not cytosol, and was both time- and temperature-dependent. DLS were more effective than either endoplasmic reticulum or plasma membrane as the donor fraction. The results from the cell-free analysis suggest a possible functional role of the DLS in sterol biogenesis and transfer to the plasma membrane during spermatid development.Abbreviations DLS
dictyosome-like structure(s)
- PBS
phosphatebuffered saline
- HEPES
4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid
- BSA
bovine serum albumin 相似文献
40.
Malignant transformation of immortalized transgenic hepatocytes after transfection with hepatitis B virus DNA 总被引:28,自引:2,他引:26
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Persistent infection by hepatitis B virus (HBV) is epidemiologically correlated with the prevalence of hepatocellular carcinoma, but its role in tumor development is not yet understood. To study the putative oncogenic potential of HBV, a non-malignant immortal mouse hepatocyte line FMH202 harboring metallothionein promoter-driven simian virus 40 large tumor antigen was transfected with HBV DNA. All stably transfected clones which replicated HBV displayed malignant growth characteristics in soft agar and were tumorigenic upon inoculation in nude mice. The nude mice tumors were histologically classified as differentiated or anaplastic hepatocellular carcinomas. As with human liver carcinomas, rearrangements of in vitro integrated HBV sequences were observed in the nude mouse tumors, and in tumor-derived cell lines. In one case, expression of viral core and surface antigens was blocked in the tumors, correlating with hypermethylation of the HBV genome. However, the expression of X gene was maintained in most tumors and tumor-derived cell lines. X protein was detected in nuclei by immune fluorescence and by immune blot. These results provide the first demonstration that HBV displays oncogenic potential in an experimental system. This system could be useful to functionally identify HBV genes which convey a tumorigenic phenotype. 相似文献