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131.
Two isolectins (L4E0-PHA and L0E4-PHA) from red kidney beans (Phaseolus vulgaris) were isolated by affinity chromatography on immobilized thyroglobulin and by chromatography on hydroxyapatite. The L4E0-PHA siolectin was not retarded on the affinity column and was eluted from the hydroxyapatite column with a 0.1 M Phosphate buffer. This isolectin had no erythroagglutinating activity but had high lymphoagglutinating and lymphocyte stimulating activities. The L0E4-PHA isolectin was adsorbed on the affinity column and was eluted from the hydroxyapatite column with a 0.25 M Phosphate buffer. This isolectin has a high erythroagglutinating activity, a very low lymphoagglutinating activity and no lymphocyte stimulating activity. These two isolectins are shown however to be closely related with respect to their oligomeric structure and reactivity towards anti-PHA antibodies. The lack of mitogenic activity of the L0E4-PHA isolectin suggests that in the other isolectins, the E monomer is not responsible for their mitogenic activity and that the membrane glycoproteins, which contain the E monomer — specific oligosaccharide, are not involved in the process inducing mitosis. 相似文献
132.
Four strains of both Taphrina pruni and T. institiae were cultivated under identical conditions and and lipids and fatty acids were quantitatively analysed at two stages of their development. Tri- and diglycerides are the major neutral lipids in both species. Phosphatidylcholine and phosphatidylethanolamine are the most abundant polar lipids. Qualitatively, the two species show identical fatty acid contents, except for margaric acid (17:0) which was only found in Taphrine pruni. Quantitatively there are several differences: palmitoleic acid (16:1) occurs in reasonable amounts regularly and only in Taphrina pruni. The ratios 16:0/18:0 and 18:1/18:2 are generally higher for T. insititiae whereas the degree of unsaturation of fatty acids is higher in the former. The results are discussed with regard to data on other fungal species. 相似文献
133.
134.
M Guinand M J Vacheron G Michel 《Biochemical and biophysical research communications》1978,80(2):429-434
In two strains of Bacillus, the synthesis of two specific lytic enzymes was studied concomitantly with an inhibition of the sporulation: LD-carboxypeptidase synthesis was unaffected whereas γ-D-glutamyl-(L)meso-diaminopimelyl endopeptidase synthesis was shown to be closely related to sporulation. The endopeptidase production is totaly inhibited when netropsin inhibits sporulation in B. sphaericus and is low in B. subtilis Thy?A when sporulation is inhibited by thymidine starvation. This enzyme seems directly connected with the sporulation sequence. 相似文献
135.
Infrared spectroscopy and 1H nmr have been used to elucidate the association modes of leucine dipeptides in carbon tetrachloride solution. Two stereoselective types of aggregates have been evidenced. Homochiral molecules are associated in oligomeric aggregates and accommodate a β-parallel-like structure which was characterized by x-ray diffraction. Heterochiral molecules are paired in centrosymmetrical dimers; the latter aggregation mode restricted to the dimer stage predominates in racemic solutions. A theoretical model proposed to account for this aggregation process is consistent with the experimental nmr data. Both homo- and heterochiral association constants are estimated from vapor pressure and nmr experiments. 相似文献
136.
Structural requirements for maximal inhibitory allosteric effect of estrogens and estrogen analogues on glutamate dehydrogenase 总被引:1,自引:0,他引:1
The inhibition of glutamate dehydrogenase by estrogens, estrogen analogues or polyphenylethylene derivatives (about one hundred molecules, most of them having estrogenic or antiestrogenic activities) was measured. The efficiency of these compounds in inducing allosteric inhibition of the enzyme was compared and correlated to their chemical structure: an aromatic ring A, a free phenolic group in the region of carbon 3 of the steroid nucleus and a lipophilic substitution in the region of C-12, C-13 or C-17 were found to be the main structural features required for maximal efficiency on glutamate dehydrogenase. A tentative model for the relative orientation of the main inhibitor families is proposed. It accounts for most of the kinetic results and can be used as a tool for the selection of affinity labels directed towards the estrogen binding site of glutamate dehydrogenase. 相似文献
137.
138.
André Welter Joseph Jadot Gaston Dardenne Michel Marlier Jean Casimir 《Phytochemistry》1976,15(5):747-749
A new natural imino-alcohol, 2,5-dihydroxymethyl 3,4-dihydroxypyrrolidine has been isolated from the leaves of Derris elliptica. Its structure was determined by chemical and physical methods. 相似文献
139.
Michel Melou 《Geobios》1976,9(6):693-717
Three species of Orthida are described from the «Schistes de Postolonnec Formation. The distribution of Crozonorthis musculosa n. g., n. sp. allows to improve the correlations between the Iberic Peninsula and the Armorican massif and supply new arguments for a Llandeilian age to a part of the «Schistes de Postolonnec Formation. 相似文献
140.