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41.
White, pink, orange, and yellow strains ofUstilago violacea containing high and low levels of cytochrome c and various carotenes were exposed to ultraviolet light. The survival curves for all strains were of exponential decay form, but the carotene-accumulating strains were generally more resistant to UV than those strains with no carotenes at all. The UV exposure time leading to 90% loss in viability, LD90, was quantitatively related to the carotene content in the form of a power function, where LD90 increased as the fifth root of the total carotene content per cell. We also determined that the ratio of total carotenes to total cytochrome c per cell was quantitatively related to the rate of viability loss during UV exposure. 相似文献
42.
Marden A. De Alvarenga Oscar Castro C. Astréa M. Giesbrecht Otto R. Gottlieb 《Phytochemistry》1977,16(11):1801-1804
Six bicyclo[3,2,1]octanoid neolignans, isolated from the benzene extract of Aniba simulans Allen (Lauraceae) trunk wood, are shown to derive from two basic structures: 1-allyl-8-hydroxy-6-(3′-methoxy-4′,5′-methylenedioxyphenyl)-7-methyl-3-oxobicyclo[3,2,1]octane, substituted by 4-hydroxy, 4-hydroxy-5-methoxy, 4-methoxy or 4,5-dimethoxy groups; and 1-allyl-8-hydroxy-6-(3′-methoxy-4′,5′-methylenedioxyphenyl)-7-methyl-4-oxobicyclo[3,2,1]oct-2-ene, substituted by 3-hydroxy or 3-hydroxy-5-methoxy groups. The structural proposals are based on spectral data, interconversions synthesis of a derivative from the known (2R,3S,3aS)-3a-allyl-5-methoxy-2-(3′-methoxy,4′,5′-methylenedioxyphenyl)-3-methyl-2,3,3a,6-tetrahydro-6-oxobenzofuran. 相似文献
43.
Marden A. de Alvarenga Raimundo Braz Fo Otto R. Gottlieb João P. de P. Dias Aderbal F. Magalhães Eva G. Magalhães Gouvan C. de Magalhães Mauro T. Magalhães José G.S. Maia Raquel Marques Anita J. Marsaioli Antônio A.L. Mesquita Anselmo A. de Moraes Alaide B. de Oliveira Geovane G. de Oliveira Gentil Pedreira Sebastião K. Pereira Sonildes L.V. Pinho Celira C. Santos 《Phytochemistry》1978,17(3):511-516
Wood samples, infested by fungi during storage, were shown to contain, besides the known 5-methyl-mellein, additional (3R)-8-hydroxy-3-methyl-3,4-dihydroisocoumarins substituted by 7-methyl, 5-formyl, 5-carboxy, 5-hydroxy, 5-methoxy, 6-methoxy-5-methyl and 6,7-dimethoxy-5-methyl groups, as well as 6-formyl-7-hydroxy-5-methoxy-4-methylphthalide. Several 2-methylchromanones were synthesized in order to show that this class of compounds can be distinguished from 3-methyl-3,4-dihydroisocoumarins by MS. 相似文献
44.
45.
Extraction of whole lobes of normal rat liver with dimethyl sulphoxide (DMSO) under N2 gives extracts which contain 5—10 μmol/l·O?2 (50-100 nmol·O?2 per 10 ml extract per 4 g liver; 1.25-2.50 nmol·O?2 per millilitre per gram liver). Evidence for ·O?2 in the extracts is given by: (1) electron spin resonance signals (ESR), (2) differential pulse polarography (DPP), (3) chemiluminescence (CL), and (4) nitroblue tetrazolium reduction (NBT). All tests yield results identical with those obtained with authentic ·O?2. Extraction of ·O?2 is enhanced by tetrabutyl ammonium ion, and is maximal at 1-3 min. These results raise the possibility that substantial amounts of ·O?2 are normally sequestered in protective membranous sites in vivo. 相似文献
46.
The aquatic fungus Blastocladiella emersonii provides a system for studying the regulation of expression of regulatory (R) and catalytic (C) subunits of cAMP-dependent protein kinase (PKA). Blastocladiella cells contain a single PKA with properties very similar to type II kinases of mammalian tissues. During development cAMP-dependent protein kinase activity and its associated cAMP-binding activity change drastically. We have previously shown that the increase in cAMP-binding activity during sporulation is due to de novo synthesis of R subunit and to an increase in the translatable mRNA coding for R (Marques et al., Eur. J. Biochem. 178, 803, 1989). In the present work we have continued these studies to investigate the mechanism by which the changes in the level of kinase activity take place. The C subunit of Blastocladiella has been purified; antiserum has been raised against it and used to determine amounts of C subunit throughout the fungus' life cycle. A sharp increase in C subunit content occurs during sporulation and peaks at the zoospore stage. Northern blot analyses, using Blastocladiella C and R cDNA probes, have shown that the levels of C and R mRNAs parallel their intracellular protein concentrations. These results indicate a coordinate pretranslational control for C and R subunit expression during differentiation in Blastocladiella. 相似文献
47.
Oscar Lazcano Jorge Bilbao Robert S. Beissner Martha Vandiver Chin Yang Li 《Biotechnic & histochemistry》1992,67(1):14-20
Permanent preparations of air dried synovial fluids were prepared by staining calcium compounds with alizarin red S stain; each slide was coverslipped with Permount. Variables studied were: (a) concentration of the solution of alizarin red S, (b) pH of staining solution, (c) time of incubation in staining solution and aqueous and ethanolic content of staining solution. The staining effect of each solution was tested on calcium pyrophosphate dihydrate, calcium oxalate, apatite and monosodium urate (MSU). Of all the solutions, best results were obtained with 0.25% alizarin red S in 50% ethanol at pH 7.0 for 30 min. With this solution, the calcium-containing compounds were well stained. MSU did not stain and still preserved negative birefringence on polarizaton. Fixation of smears with ethanol served a double purpose: It fixed the slides without dissolving or removing MSU or the calcium compounds, yet it did dissolve five corticosteroids commonly used for intra-articular injection which may interfere with interpretation of compensated polarized light microscopy of synovial fluids. 相似文献
48.
H B Nader M A Porcionatto I L Tersariol M A Pinhal F W Oliveira C T Moraes C P Dietrich 《The Journal of biological chemistry》1990,265(28):16807-16813
The purification of two heparitinases and a heparinase, in high yields from Flavobacterium heparinum was achieved by a combination of molecular sieving and cation-exchange chromatography. Heparinase acts upon N-sulfated glucosaminido-L-iduronic acid linkages of heparin. Substitution of N-sulfate by N-acetyl groups renders the heparin molecule resistant to degradation by the enzyme. Heparitinase I acts on N-acetylated or N-sulfated glucosaminido-glucuronic acid linkages of the heparan sulfate. Sulfate groups at the 6-position of the glucosamine moiety of the heparan sulfate chains seem to be impeditive for heparitinase I action. Heparitinase II acts upon heparan sulfate producing disulfated, N-sulfated and N-acetylated-6-sulfated disaccharides, and small amounts of N-acetylated disaccharide. These and other results suggest that heparitinase II acts preferentially upon N,6-sulfated glucosaminido-glucuronic acid linkages. The total degradation of heparan sulfate is only achieved by the combined action of both heparitinases. The 13C NMR spectra of the disaccharides formed from heparan sulfate and a heparin oligosaccharide formed by the action of the heparitinases are in accordance to the proposed mode of action of the enzymes. Comparative studies of the enzymes with the commercially available heparinase and heparitinase are described. 相似文献
49.
We examined the effect of ovule position within the ovary on the probability of seed maturation, on seed weight, and on progeny performance in the outbreeding legume Phaseolus coccineus. Ovaries of P. coccineus possess six linearly arranged ovules (ovule position one = stylar end). We found that in both 1987 and 1988, ovule position had a significant effect on the probability of seed maturation under field conditions. In 1987, ovule positions one. two, and three had a higher probability of maturing seeds than the three most basal ovule positions. In 1988, the probability of producing a mature seed in ovule position one was more similar to the three most basal ovule positions than to ovule positions two and three. The position of the ovule in the ovary had no significant effect on seed weight in 1987, but it had a significant effect in 1988. Overall, seeds from ovule positions one, two, and three tended to produce heavier seeds than the three most basal ovule positions. The effects of ovule position on progeny performance were determined in a greenhouse and a field study. In the greenhouse study, we found no significant overall effect of the position of the ovule that produced the seed on progeny performance. In the field study, we did find a significant ovule position effect on several measures of reproductive performance as well as an overall effect on reproductive performance. In addition, we found a significant interaction between ovule position and number of seeds per fruit. Progeny from the stylar end of the fruit outperformed the progeny from the peduncular end in fruits containing many seeds, whereas there were no significant differences between progeny produced in the stylar and peduncular ends of fruits containing few seeds. Causes of position effects are unknown but hypotheses abound. 相似文献
50.
R. Rodney Howell Amir I. Arbisser David S. Parsons Charles I. Scott Ursula Fraustadt William R. Collie Robert N. Marshall Oscar Cavazos Ibarra 《American journal of human genetics》1981,33(6):957-967
We have defined a new autosomal recessive disorder in patients stemming from a small community in northern Mexico. Diagnosable at birth, its major symptoms include brittle hair, mental retardation, and nail dysplasia. Structural hair abnormalities are seen by both light and electron microscopy. Hair cystine content is reduced while the copper/zinc ratio in hair is increased. 相似文献