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Angelo Benedetti Marco Ferrali Elisabetta Chieli Mario Comporti 《Chemico-biological interactions》1974,9(2):117-134
The relationships between the peroxidation of musomal lipids and the early liver damage have been investigated in rats pretreated with progressively higher doses of α-tocopherol (vit. E) and intoxicated with various amounts of carbon tetrachloride.Pretreatment of rats with vit. E at 25 body wt. has minor effects on both the peroxidation of musomal lipids and the liver triglyceride accumulation in rats poisoned with CC14 at 250 body wt. However, a decrease of the peroxidative reaction and of the liver steatosis occurs when the rats are pretreated with progressively higher doses of vit.E. A close correlation exists between the two phenomena, when the intoxication is accomplished with CC14 at 250 body wt. Also, the musomal concentration of α-tocopherol is strictly correlated to both the decrease of musomal lipoperoxidation and the decrease of liver triglyceride accumulation. The CCl4-induced impairment of musomal glucose-6-phosphatase and the incorporation of 14C from 14CC14 into liver musomal lipids are not affected by vit. E pretreatment.The extent of musomal lipoperoxidation is not correlated to the liver triglyceride accumulation when vit. E-pretreated rats are given CC14 at 25 or 2.5 body wt. However, a correlation between lipoperoxidation and liver steatosis occurs when non-pretreated rats are challenged with the three different doses of the halogenated hydrocarbon. 相似文献
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Pi-Kwang Tsung S.W. Kegeles E.L. Becker 《Biochimica et Biophysica Acta (BBA)/General Subjects》1977,499(2):212-227
The intracellular localization and properties of the chymotrypsin-like esterase activity ( esterase acitivity) of the rabbit peritoneal neutrophil has been studied and shown to differ from that of the human neutrophil.The major portion of the esterase activity in the rabbit neutrophil is in the 100 000 × g supernatant fraction with distinctly less activity in the lysosomal fraction. The 100 000 × g supernatant contained the highest relative specific activity of any of the subcellular fractions. Rabbit peripheral blood neutrophils gave the same distribution.The 100 000 × g supernatant esterase is 95% esterase 1 and 5% esterase 3, whereas, the lysosomal esterase is 78% esterase 1, 10–16% esterase 2 and 9% esterase 3 as defined by their ability to be inhibited by p-nitrophenyllethyl-5-chloropentylphosphonate. The 100 000 × g supernatant The 100 000 × g supernatant and lysosomal esterase activities further differ in their susceptibility to other inhibitors, their pH optima, ease of elution from DEAE and isoelectric points. Two molecular weight species of 174 000 and 70 000 were found in the 100 000 × g supernatant fraction and extracts of the lysosomal fraction but usually in differing proportions.In confirmation of others, essentially all of the chymotrypsin-like esterase activity ( esterase activity) of the human neutrophil is in the lysosomal fraction, unlike the rabbit cell. The human neutrophil esterase was less susceptible to inhibition by p-nitrophenylethyl-5-chloropentylphosphonate and diisopropylphosphofluoridate but more susceptible to soybean trypsin inhibitor than rabbit esterase activity. The pH optimum of the human neutrophil esterase differed from either the rabbit lysosomal or 100 000 × g supernatant esterase, as did the isoelectric point and molecular weights. 相似文献
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Determination of 2,4-dihydroxy-1,4(2h)-benzoxazin-3-one glucosides in corn (Zea mays L.) 总被引:2,自引:0,他引:2
A method has been developed for the determination of 2,4-dihydroxy-1,4(2H)-benzoxazin-3-ones, which occur in corn (Zea mays L.) plants as glucosides. The method involves freezing and thawing of corn tissue samples to allow enzyme-catalyzed cleavage of the glucosides, fragmentation, extraction of the released aglycons, removal of chlorophyll, conversion of the 2,4-dihydroxy-1,4(2H)-benzoxazin-3-ones to the more stable 2(3)-benzoxazolinones, extraction of the 2(3)-benzoxazolinones, and quantitative ir measurement of the 2(3)-benzoxazolinones in methylene chloride solution. The amount of 2(3)-benzoxazolinone calculated as 6-methoxybenzoxazolinone (MBOA) obtained from B37 × B14 single-cross corn was found to be fresh weight (10 samples; SD 0.16 mg). For synthetic samples, the precision of the method is that of the reproducibility of the spectrophotometer used. Depending upon the spectrophotometer used, a detection limit of fresh tissue was observed. 相似文献
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Under the same solution conditions, the apparent weight average sedimentation coefficient, swa, and some quantities obtained from it can be combined with the equilibrium constant or constants, Ki, and the monomer concentration, cI, obtained from sedimentation equilibrium, light scattering or osmotic pressure experiments on the same self-associating solute, so that the individual sedimentation coefficients, si, of the self-associating species, and also the hydrodynamic concentration dependence parameter,g or , can be evaluated. Using two different models for the hydrodynamic concentration parameter, four different methods are presented for the evaluation of the si's. Methods for evaluating g or , once the si's are known, are presented. A method for obtaining the number average sedimentation coefficient, sN, and its application to self-associations is presented. Methods are shown for the evaluation of Z average properties, xzc, as well as number average properties,xNc, of a self-associating solute from its weight average properties, xwc. 相似文献
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Pea seeds were imbibed in radioactive choline and then germinated. Treatments were either at 5° or 25° and the seeds were imbibed for 5 hr at one temperature and then transferred to the other. [-14C]Choline incorporation into phosphatidyl choline in the ER and the plasma membrane obtained from the embryonic axes after germination was measured. Seeds kept constantly at 25° had a very rapid initial incorporation of choline followed by a loss of label. Seeds kept at 5° had a very much lower rate of incorporation. However, seeds transferred from 5 to 25° behaved for at least 48 hr as if continuously kept at 5°, while in seeds transferred from 25 to 5° incorporation stopped after 15 hr. The seeds apparently respond to transient exposure to temperature by a changed metabolism of phospholipid. Data are also given for the choline content of the seeds under the different treatments and for the changes in total phospholipid. 相似文献
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B.V. Chernyak P.A. Dibrov A.N. Glagolev M.Yu. Sherman V.P. Skulachev 《FEBS letters》1983,164(1):38-42
Motility of a marine alkali-tolerant bacterium, Vibrio alginolyticus, can be observed in the presence of high concentrations of a protonophorous uncoupler, CCCP. Motility in the CCCP-containing media is completely inhibited by decrease in extracellular [Na+] or by monensin-induced increase in intracellular [Na+]. A mutant has been selected that grows only in media supplemented with a substrate such as acetate requiring no ΔNa to be transported into the cell. Motility of the mutant was found to be completely inhibited by CCCP. Cyanide, CCCP and vanadate added separately or in twos inhibit motility only partially. The three poisons added together completely paralyse the cells. In this inhibitor cocktail, arsenate can substitute for CCCP + vanadate; cyanide can be replaced by anaerobiosis. It is concluded that (i) ΔNa rather than ΔNH powers the flagellar motor of V. alginolyticus in the presence of CCCP, and (ii) in addition to the Na+-motive respiratory chain [Tokuda, H. and Unemoto, T. (1982) J. Biol. Chem. 257, 10007–10014] there is a vanadate and arsenate-sensitive oxygen-independent mechanism of ΔNa generation, presumably an ion-motive ATPase. A suggestion is put forward that circulation of Na+ can replace that of H+ in V. alginolyticus, ΔNa being formed by the Na+-motive respiratory chain and utilized by Na+-solute symporters, the Na+-driven flagellar motor and maybe by a reverse ion-motive ATPase. 相似文献
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A simple micro method for the estimation of urinary pregnanediol (5β-pregnane-3α,20α-diol) is described. Chloroform extracts of acid-hydrolyzed urine are assayed gas chromatographically at 235° using Gas Chrom Z coated with 0.5 gm % NPGA. Thirty urine specimens may be prepared for gas chromatography in 1.5 hr. The rate of hydrolysis of pregnanediol glucuronide is proportional to the concentration of acid, and the rate of decomposition of pregnanediol to the square of acid concentration. Normal pregnant women excreted a mean of pregnanediol in the first trimester, in the second, and in the third. During the luteal phase of the menstrual cycle the excretion of pregnanediol by normal women increased from to . 相似文献
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Previous reports indicate that alterations of activity of cholinergic neurons are followed by parallel changes in sodium-dependent high affinity choline uptake . These results are consistent with the proposal that this portion of choline uptake is regulatory in the synthesis of ACh. These results also suggest the possibility of utilizing sodium-dependent high affinity choline uptake as a measure of the relative state of cholinergic activity . In this study, we administer a number of drugs reported to alter turnover and release of ACh (both are measures of cholinergic activity , and subsequently examine sodium-dependent high affinity choline uptake . Administration of pentobarbital, chloral hydrate, morphine, physostigmine, Δ9 THC, hemicholinium-3 and oxotremorine, drugs which decrease ACh turnover and release, caused a reduction in choline uptake. Conversely, administration of pentylenetetrazol, atropine, scopolamine, and haloperidol, drugs which increase ACh turnover and release, caused an increase in choline uptake . These findings support the proposal that sodium-dependent high affinity choline uptake can be used as a relative measure of the activity of cholinergic neurons . 相似文献
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Gas chromatography-chemical ionization mass spectrometry has been applied successfully in the analysis of choline and its esters. This approach serves to extend further the potential of existing gas chromatographic procedures which are capable of the microestimation of choline esters following their N-demethylation by either chemical or physical means. Typical fragmentation patterns with ions at and were obtained for each choline ester derivative. When methane was used as the reactant gas, the above fragments were approximately of equal abundance for each ester. Use of isobutane as reactant gas yielded almost 80% of the (M + 1) fragment, and only approximately 5% of the fragment ion at . Recovery of all fragments was linear for nondeuterated as well as deuterated analogs of choline ester derivatives. Recovery, as evident from the analysis of records of relative ratios of injected isotopic variants of these esters, indicated that this analysis of choline esters using chemical ionization mass spectrometry coupled with gas chromatography is quantitative and highly reproducible. 相似文献
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The flameless atomic absorption method described here is a simple, rapid, accurate microtechnique for determining zinc in aqueous solutions, serum, or urine. It requires no sample pretreatment, only 1.0 μl of sample per determination, no correction for viscosity differences between sample and standard solutions, and is not subject to ionic or organic interference. The average recovery of added zinc in serum is 97.5% and in urine is 97.6%. The values obtained for serum (mean ± SD: 94.6 ± 11.0 μAg/100 ml; N = 25) and urine (range: ; N = 4) are comparable to the values reported in the literature. The coefficient of variation was less than 5.0% in all cases. The qualitative concentration limit was . The techniques and instrumentation described are also applicable to a number of trace minerals of common interest. 相似文献
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Occurrence of two serologically distinct groups within Bacillus thuringiensis serotype 3 ab var. kurstaki 总被引:7,自引:0,他引:7
Two groups distinguishable on the basis of crystal serology have been identified within Bacillus thuringiensis var kurstaki (serotype 3 ab). The toxicities of these two groups to Trichoplusia ni and Heliothis virescens expressed as ratio also differed. It is suggested that serotype 3 ab be separated into two subgroups designated as K-1 and K-73. 相似文献
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The relationship between chromosome replication and the bacterial division cycle has been examined in three substrains of Escherichia coli obtained from different sources and designated A, F and K. At growth rates greater than 1.0 doubling per hour (μ > 1.0), the time for a round of chromosome replication (C) was 42 minutes in all three substrains, but the time between the end of a round and cell division (D) was 22 minutes in A, 16 minutes in F and 14 minutes in K. At slower growth rates C and D increased, but to significantly different extents in the three substrains. When μ = 0.5, C and D were approximately 80 and 40 minutes in A, 60 and 20 minutes in F, and 70 and 20 minutes in K.As a consequence of the lengths of the C and D periods in the three stocks of E. coli, the patterns of chromosome replication during the division cycle differed. The most obvious difference was that E. coli F and E. coli K possessed periods devoid of DNA synthesis at both the beginning and the end of the division cycle during slow growth, whereas E. coli A contained only one period devoid of DNA synthesis at the end of the cycle. 相似文献
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Methods have been modified and adapted to permit enzymic automated micro analysis of glucose on 0.021 ml of blood, and of lactic acid on 0.0115 ml of blood. By means of a single 1:20 Somogyi filtrate with a final volume of 1–1.4 ml prepared from 0.1–0.15 ml blood, both determinations can be accomplished individually on the autoanalyzer.The range of concentrations of each method has been extended so that glucose may be determined between 5 and (or higher depending on dilution) and lactic acid between 5 and .The methods are sensitive, reproducible, and stable. The recoveries and the comparison studies with manual methods are well within the limits of clinical investigation procdures. 相似文献
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M Novak 《International journal for parasitology》1974,4(4):371-374
The number of tetrathyridia in the peritoneal cavities of mice increases exponentially with time. Thirty days post infection more larvae are in the cavities than in the livers. After that the increase of intraperitoneal populations continues, whereas the number of tetrathyridia in the livers remains more or less constant.Exogenous testosterone propionate, 10 , twice a week, for 5 weeks, increases significantly the total volumes of tetrathyridial populations in the peritoneal cavities, whereas oestradiol benzoate, 5 or 10 , also for 5 weeks, accelerates the rate of growth and multiplication of coelomic tetrathyridia to a much lesser extent, but increases significantly the infection of the livers. 相似文献
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Chenooxazoline3 (50–100 μM) inhibited (>50%) both 7α and 7β-dehydroxylase activities in whole cells and cell extracts of sp. V.P.I. 12708. Chenooxazoline (>50 μM) and methylchenooxazoline (>25 μM) but not lithooxazoline (≤100 μM) inhibited growing cultures of sp. V.P.I. 12708. Chenooxazoline (100 μM) also inhibited the growth of certain members of the genera , , and but not , , or the eucaryotic microorganism, (_< 400 μM). 相似文献
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M Hamberg 《Analytical biochemistry》1973,55(2):368-378
A method was developed for quantitative determination of 5α,7α-dihydroxy-11-ketotetranor-prostane-1,16-dioic acid, the major urinary metabolite of prostaglandins F1α and F2α in man. The method was based on the use of the O-methyloxime derivative of [5β-3H; 10,10,12,12-2H4]5α,7α-dihydroxy-11-ketotetranor-prostane-1,16-dioic acid as internal standard and determination of ratios between unlabeled and deuterium-labeled molecules by multiple-ion analysis. Excretion values found for healthy human subjects were: males, (n = 10, mean value, 24.0 ± 17.2 (SD) μg) and females, (n = 10, mean value, 10.5 ± 2.1 (SD) μg). 相似文献