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31.
Chair of Committee for Mouse Chromosome 13 相似文献
32.
A rapid method for preparation of plasma membrane fromAcanthamoeba culbertsoni involving toluene treatment followed by lithium bromide extraction is described. In the plasma membrane preparation,
5′-nucleotidase, Na+ + K+ -ATPase, Mg2+ -ATPase and glucose-6-phosphatase activities were enriched. The membrane preparation was free from nucleic acid, cytochrome
P-450 and cytochrome b5. Amino acid (14C-Ieucine) was not incorporated in the plasma membrane in 2 min. Succinic dehydrogenase was not detectable in the plasma membrane
preparation. The molar ratio of cholesterol and phospholipids was 0.95 which is characteristics for plasma membranes. Under
electronmicroscopy the preparation was homogenous without any other component of the cell. Plasma membrane proteins and glycoproteins
were separated on acrylamide gel electrophoresis 相似文献
33.
In this paper, we describe a temperature-sensitive mutant of the yeast Saccharomyces cerevisiae (P5-9) which at a restrictive temperature (36 degrees C) shows a pleiotropic defect for transport of many different metabolites. The temperature sensitivity of the mutant is closely related to a reduction in phosphofructokinase activity. This conclusion is based on the following criteria. (i) Both the primary isolate, designated P5-9 (ts [rho-] Ino-), which is an inositol auxotroph and respiration deficient, and a purified derivative, SB4 (ts [rho+] Ino+ ), which is respiration competent and capable of growing in the absence of inositol, are temperature sensitive for growth and ethanol production in media containing glucose or fructose as the sole carbon source. (ii) The respiration-competent derivative SB4 is not temperature sensitive in media containing glycerol or glycerol-pyruvate; glucose inhibits its growth at 36 degrees C in these media. (iii) Assays of glycolytic enzymes in P5-9 and SB4 extracts, prepared from cells incubated for 1 to 2 h at 36 degrees C before harvesting, show selective reduction in phosphofructokinase activity. Analysis of tetrads derived from the cross of mutant and nonmutant haploids indicates that temperature sensitivity for growth is due to a single gene or to two closely linked genes. The biochemical analysis of spores from seven such tetrads revealed a uniform cosegregation of temperature sensitivity for growth and phosphofructokinase activity. Transport and ATP levels were drastically reduced in SB4 cells incubated at 36 degrees C for 1 to 2 h with glucose as the carbon source, but not when glycerol-pyruvate or lactate was the energy source. Therefore, depletion of energy as a result of phosphofructokinase inactivation appears to be the cause of the pleiotropic transport defect observed in the mutant. 相似文献
34.
The flag and second leaves of wheat showed physiological and biochemical differences in the normal and water stressed plants.
Although the flag leaf had lower enzyme activities in the control plants, in stressed plants it could continue nitrate assimilation
better than the second and other leaves. The flag leaf also exhibited a higher tendency to resume normal metabolic activity
after the release of stress as is indicated by higher NRA, NiRa, lower rad and rab. 相似文献
35.
An indole 2,3-dioxygenase was purified ca 38-fold from maize leaves. The enzyme had an MW of about 98000, an optimum pH of 5.0 and the energy of activation was 9.1 kcal/mol. The Kmax for indole was 1.4 × 10?4 M. The enzyme was inhibited by diethyldithiocarbamate, salicylaldoxime and sodium dithionite. The inhibition by diethyldithiocarbamate was specifically reversed by Cu2+. The dialysed enzyme was stimulated by Cu2+. Four atoms of oxygen were utilized in the disappearance of 1 mole of indole. Inhibition of the enzyme by -SH compounds and -SH group inhibitors, and their partial removal by Cu2+ only, suggested the involvement of -SH groups in binding of Cu2+ at the catalytic site. 相似文献
36.
Uncertainties surrounding the structures of the Δ7-sterols in the seeds of Cucurbita maxima have been resolved. Seven components were found by TLC, GLC, HPLC, mass spectrometry and 1H NMR. They were 24β-ethyl-5α-cholesta-7,22,25(27)-trien-3β-ol, 24β-ethyl-5α-cholesta-7,25(27)-dien-3gb-ol, avenasterol, spinasterol, 24-dihydrospinasterol, 24ζ-methyllathosterol and 25(27)-dehydrofungisterol. The 1H NMR spectra indicated that the sterols with an ethyl substituent at C-24 occurred in the absence of their C-24 epimers. This seems to be the first instance of the detection of 25(27)-dehydrofungisterol in a higher plant. 相似文献
37.
The solvation properties of ubiquinone-10 and ubiquinol-10 in a wide variety of solvents of polarity varying from alkanes to water are reported. Greatest solubility is observed in solvents of intermediate polarity and particularly where low polarity is combined with a pronounced tendency to interact with the benzoquinone substituent of the ubiquinone molecule. This includes solvents like chloroform and benzene. Ubiquinone-10 is somewhat less polar than ubiquinol-10 as judged by comparative solubilities of the two molecules. Proton-NMR chemical shift measurements and aggregation studies in selected solvents indicate that in ubiquinone-10 in the liquid phase and in solution in hydrocarbons like dodecane the molecules have a preferred association possibly involving stacking of the benzoquinone rings. Surface balance studies indicated that the surface-active character of ubiquinone-10 is relatively weak and only in a comparatively polar and highly structured solvent, formamide, was there evidence of an effect on surface tension of the solvent. The critical micelle concentratiom in this solvent was estimated to be about 5 M on the basis of surface tension measurements. Ubiquinone-10 is well known to form virtually insoluble monolayers at the air/water interface. Studies of the partition of ubiquinone-10 in binary mixtures of solvents suggest that the interaction of the benzoquinone ring substituent with structured polar solvents is considerably weaker than the internal cohesion between molecules of the solvent. No evidence on the basis of wide-angle X-ray diffraction measurements was obtained to indicate that solvent molecules were a component of the crystal lattice of ubiquinone-10 that had precipitated from solvent mixtures. 相似文献
38.
The uptake of nutrients was investigated in the renal cortical brush border membrane (BBM) vesicles at different stages of ascending pyelonephritis. There was significant difference (p less than 0.05) in the uptake of D-glucose, L-alanine, L-aspartate, L-lysine and L-proline 3 days postinfection and onwards in both right unobstructed and left obstructed experimental kidneys as compared to the sham operated control. The uptake of D-glucose, L-lysine and L-proline was found to be significantly decreased (p less than 0.05) during the course of infection. While uptake of L-alanine and L-aspartate increased (p less than 0.05) in early stages and decreased (p less than 0.05) in later stages of infection. The differential effect was attributed to the compensatory measure and different kinds of transport systems for different types of amino acids. 相似文献
39.
Monica Gubersky D. M. P. Thomson Mark Lajzerowicz 《Cancer immunology, immunotherapy : CII》1986,21(2):107-113
Summary Human cancers express organ-specific cancer neoantigens (OSN) as determined by in vitro leukocyte responses to extracts of cancers by the tumor host. In this study, we determined whether the OSNs were normal developmental proteins that were expressed by fetal organs and re-expressed with oncogenesis. Fetal extracts, principally of lung and colon but also of liver and kidney, were tested for their ability to induce leukocyte adherence inhibition (LAI) as compared to extracts from adult tissues of the same organ. Leukocytes from lung cancer patients showed positive LAI responses to 13- and 19-week fetal lung tissue. Likewise, leukocytes from colon cancer patients showed positive LAI responses to 14- and 19-week fetal colon tissue, whereas leukocytes from control subjects did not. Neither group responded positively to 21-week fetal organs. Criss-cross experiments showed that the fetal antigen was organ specific. Multiparous pregnant women showed positive LAI responses to cancer extracts but not to extracts from normal tissues of the same organ. The pattern of the LAI response was bell-shaped. Positive LAI responses to lung and breast cancer were detected at 4 to 7 months gestation and peaked at 5 months. To the fetal colon, LAI positive responses were detected at 5 to 8 months gestation, with the peak response at 6 months. The results indicate that OSN of cancers are also expressed by fetal organs and sufficient antigen is shed by fetal organs to sensitize pregnant women. Older fetal organs (21 weeks) and adult organs do not express an immunogenic or antigenic OSN.Supported by a grant from the National Cancer Institute of Canada 相似文献
40.