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31.
Salvatore Oliviero Mario DeMarchi Angelo O. Carbonara Luigi F. Bernini Giuliano Bensi Giovanni Raugei 《Human genetics》1985,71(1):49-52
Summary The protein and gene structure of the Hp Johnson variant (Hp3) were analyzed in two related heterozygous individuals. The molecular weight (23kd) and amino acid composition of Hp3 alpha chain were in agreement with the triplicated structure first suggested by Smithies in 1964. Direct gene analysis by Southern blotting showed a three-fold tandem repeat of the same 1.7 kb DNA segment implicated in the Hp2 gene duplication. On the basis of these data a nine exon model for the Hp3 gene is proposed. 相似文献
32.
Dion tomasellii sp. nov. occurs with an interrupted distribution from Guerrero to central Sonora. It is characterized by falcate to subfalcate leaflets. The populations from Sonora and northern Sinaloa are segregated asD. tomasellii var.sonorense on the basis of their narrower and glaucous leaflets. 相似文献
33.
Richard M. Epand Karen Dell Witold K. Surewicz Mario A. Moscarello 《Journal of neurochemistry》1984,43(6):1550-1555
The capacity of myelin basic protein or of poly-L-lysine to promote leakage of carboxyfluorescein from vesicles or the aggregation of vesicles was studied. The vesicles were composed of phosphatidylcholine as the sole or major lipid component. Addition of 10% sphingomyelin, 10% phosphatidylglycerol, 10% egg or bovine brain phosphatidylethanolamine, or 30% dodecanal had relatively little effect on the extent of carboxyfluorescein release in the presence of either myelin basic protein or poly-L-lysine. In contrast with these results, the extent of vesicle aggregation was very sensitive to lipid composition. Addition of 10% phosphatidylglycerol induced more aggregation than the other phospholipids tested. Admixing 10% of a partially degraded sample of bovine brain phosphatidylethanolamine also led to a large amount of aggregation induced by the myelin basic protein. This latter aggregation appeared more specific for the basic protein, as it occurred to a much smaller extent with poly-L-lysine. In general, the effects of the myelin basic protein on either carboxyfluorescein release or vesicle aggregation were similar to, although somewhat greater than, that of poly-L-lysine. The aggregation of vesicles containing degradation products of phosphatidylethanolamine can be ascribed largely to the presence of aliphatic aldehydes. The effect of aliphatic aldehydes was specific in that the aliphatic alcohol, hexadecanol, or the short-chain aldehydes, acetaldehyde or butyraldehyde, did not promote myelin basic protein-induced vesicle aggregation. In addition, poly-L-lysine was less effective than the basic protein in aggregating vesicles containing aliphatic aldehydes. (ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
34.
Mario R. Tredici Teresa Papuzzo Luisa Tomaselli 《Applied microbiology and biotechnology》1986,24(1):47-50
Summary The results of a whole year experiment on the outdoor mass culture of Spirulina maxima strain 4Mx on fertilized sea-water are reported. Carbonate and phosphate precipitation in the sea-water media was prevented by maintaining a low concentration of phosphate and by controlling the pH in the range of 8.0–8.3. The mean annual yield of biomass on sea-water plus urea as nitrogen source was 7.35 g (dry weight) m-2· day-1, a value slightly lower than that obtained on the standard bicarbonate medium (8.14 g · m-2 · day-1). On sea-water plus nitrate the yield was only 5.2 g·m-2·day-1. The nitrogen content of the biomass was higher in summer and lower in winter. The seasonal effect was more evident when nitrate was the nitrogen source. 相似文献
35.
Microheterogeneity of bovine myelin basic protein studied by nuclear magnetic resonance spectroscopy
Myelin basic protein isolated from bovine white matter is known to consist of a mixture of three or more “charge isomers”, which can be separated by cation-exchange chromatography. We are using 360-MHz 1H-nmr spectroscopy to establish the chemical and structural differences among them. Preliminary studies by difference spectroscopy between two of the isomers suggest (a) all aromatic residues, and probably their nearest-neighbors, are unchanged; (b) the less cationic isomer lacks one (or two) of its C-terminal Arg residues; and (c) a significant fraction of the two Met residues in the less cationic isomer is present as methionine sulfoxide. 相似文献
36.
Simone Ottonello Giovanni Maraini Mario Mammi Hugo L. Monaco Paola Spadon Giuseppe Zanotti 《Journal of molecular biology》1983,163(4):679-681
Crystals of human plasma retinol-binding protein have been obtained from 4.5 m-NaCl buffered at pH 6.8 with 20 mm-cacodylate. The crystals are trigonal with space group R3 and unit cell dimensions, referred to the hexagonal system. . The crystals diffract to a resolution of 2.0 Å. 相似文献
37.
Acid phosphatase purified from maize scutellum, upon acylation with succinic anhydride, still shows negative co-operativity for the hydrolysis of glucose-6-phosphate at pH 5.4. This phenomenon is abolished by glucose, for both native and succinylated enzymes, through stimulation of the initial velocities at sub-optimal substrate concentrations. However, negative co-operativity for the enzymatic hydrolysis of p-nitrophenylphosphate at pH 5.4 is suppressed only at high concentrations of glucose. Furthermore, the hydrolysis of p-nitrophenylphosphate is noncompetitively inhibited (low affinity form of the enzyme molecule) by glucose, which suggests the existence of different substrate binding sites. 相似文献
38.
Mitsue Haraguchi Mario Motidome Massayoshi Yoshida Otro R. Gottlieb 《Phytochemistry》1983,22(2):561-563
The trunk bark of Ocotea catharinensis yielded, besides the known bicyclo(3.2.1)octanoid neolignans canellin-C and 5′-methoxycanellin-C, two epimers rel-(1R,4S and 4R,5S,6R,7S,8R)-1-allyl-4,8-dihydroxy-3,5-dimethoxy-7-methyl-6-piperonyl-bicyclo(3.2.1)oct-2-enes and rel-(1R,5S,6R,7S,8R)-1-allyl-3,8-dihydroxy-5-methoxy-7-methyl-6-piperonyl-4-oxobicyclo(3.2.1)oct-2-ene. The hydrobenzofuranoid neolignans are represented by the equally novel (2S,3S,5R)-5-allyl-5,7-dimethoxy-3-methyl-2-piperonyl-2,3,5,6-tetrahydro-6-oxobenzofuran and (2R,3S,3aS)-3a-allyl-5,7-dimethoxy-3-methyl-2-piperonyl-2,3,3a,6-tetrahydro-6-oxobenzofuran. 相似文献
39.
Monolayer black membranes from bipolar lipids of archaebacteria and their temperature-induced structural changes 总被引:1,自引:0,他引:1
Alessandra Gliozzi Ranieri Rolandi Mario De Rosa Agata Gambacorta 《The Journal of membrane biology》1983,75(1):45-56
The membrane of Caldariella acidophila, an extreme thermophilic archaebacterium, is characterized by unusual bipolar complex lipids. They consist of two nonequivalent polar heads, linked by a C40 alkylic component. The molecular organization of these lipids in the plasma membrane is still a matter of study. In this paper, we present current-voltage measurements on artificial bipolar lipid membranes, indicating that molecules are indeed organized as a covalently bound bilayer, in which each molecule is completely stretched and spans its entire thickness. Furthermore, conformational transitions of these artificial membranes (which could be formed only above 70 degrees C from a lipid/squalene dispersion) are analyzed in the 80 to 15 degrees C temperature range. Abrupt variations in capacitance and valinomycin-induced conductance seem to indicate the occurrence of at least two structural changes. Measurements are also extended to different solvent systems. Results are consistent with the picture of a monolayer bipolar lipid membrane in which few solvent molecules align themselves parallel to the lipophilic chains. The amount of solvent as well as the temperature at which conformational transitions occur, depend on the solvent system in which the lipid is dispersed. 相似文献
40.
Piero Cammarano Filomena Mazzei Paola Londei Angela Teichner Mario de Rosa Agata Gambacorta 《Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression》1983,740(3):300-312
Ribosomal subunits of Caldariella acidophila (max.growth temp., 90°C) have been compared to subunits of Bacillus acidocaldarius (max. growth temp., 70°C) and Escherichia coli (max. growth temp., 47°C) with respect to (a) bihelical content of rRNA; (b) G·C content of bihelical domains and (c) tightness of rRNA-protein interactions. The principal results are as follows. 1. Subunits of C. acidophila ribosomes (Tm = 90–93°C) exhibit considerable thermal tolerance over their B. acidocaldarius (Tm = 77°C) and E. coli counterparts (Tm = 72°C). 2. Based on the ‘melting’ hyperchromicities of the intact ribosomal subunits a 51–55% fraction of the nucleotides appears to participate in hydrogen-bonded base pairing regardless of ribosome source, whereas a larger fraction, 67–70%, appears to be involved in hydrogen bonding in the naked rRNA species. 3. The G·C content of bihelical domains of both free and ribosome-bound rRNA increases with increasing thermophily; based on hyperchromicity dispersion spectra of intact subunits and free rRNA, the bihelical parts of C. acidophila rRNA are estimated to contain 63–64% G·C, compared to 58.5% G·C for B. acidocaldarius and 55% G·C for E. coli. 4. The increment in ribosome Tm values with increasing thermophily is greater than the increase in Tm for the free rRNA, indicating that within ribosomes bihelical domains of the thermophile rRNA species are stabilized more efficiently than their mesophile counterparts by proteins or/ and other component(s). 5. The efficiency of the rRNA-protein interactions in the mesophile and thermophile ribosomes has been probed by comparing the releases, with LiCl-urea, of the rRNA species from the corresponding ribosomal subunits stuck to a Celite column through their protein moiety; it has been established that the release of C. acidophila rRNA from the Celite-bound ribosomes occurs at salt-urea concentrations about 4-fold higher than those required to release rRNA from Celite-bound E. coli ribosomes. 6. Compared to E. coli, the C. acidophila 50 and 30 S ribosomal subunits are considerably less susceptible to treatment designed to promote ribosome unfolding through depletion of magnesium ions. 相似文献