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951.
X-ray photoelectron spectroscopy proved very appropriate to determine the genuine oxidation state of copper in copper(D-penicillamine) chelates. The present data corroborate the ‘reductive chelation’ mechanism proposed byPeisach and Blumberg (Mol.Pharmacol. 5,200–209,1969) for the mobilization of Cu(II) with D-penicillamine (RSH). Moreover, it was concluded that the resulting complex [RSCu(I)]n is a suitable form for urinary excretion of copper.  相似文献   
952.
Hahn  Heinz 《Plant & cell physiology》1976,17(5):1053-1058
Seven natively occurring cytokinins were separated using a high-performanceliquid chromatography system. The analysis was completed in23 min. The applicability of the system is shown in determiningthe cytokinin contents in the plant pathogen Agrobacterium tumefaciensB6, which was found to contain 66 ng of N6-(2-isopentenyl) adenineper g bacteria. High-performance liquid chromatography and gasliquid chromatography are compared and evaluated for cytokinindetermination. (Received May 7, 1976; )  相似文献   
953.
Three isomeric ceramide tetrasaccharides — P blood-group active globoside, lacto-N-neotetraosyl ceramide as ABH blood-group precursor, both isolated from human erythrocytes and “asiologanglioside” from human brain as reference standard — and two ceramide pentasaccharides — H blood-group active glycosphingolipid, obtained from blood-group B active ceramide hexasaccharide of human B erythrocytes after α-galactosidase treatment and ceramide pentasaccharide from rabbit erythrocytes with B-like blood-group activity — were investigated by mass spectrometry after permethylation. The carbohydrate moiety exhibits differences not only concerning the sugar sequence but also with regard to the position of some glycosidie linkages: Oligosaccharides containing N-acetylhexosamine substituted at position 4 produce spectra that are distinctly different from those containing C-3 substituted N-acetylhexosamines, thus allowing the differentiation between type 1 and type 2 carbohydrate chains. Moreover, oligosaccharide ions with a hexose at the cleavage site exhibit a fragmentation pattern different from those with a N-acetylhexosamine at the “reducing terminal”. The intensity ratio between parent ion and parent ion — 32 mass units is Q ? 3 in the first case, whereas in the latter case Q is <1. The Q-values are given for 14 oligosaccharide ions. Differences in the composition of the ceramide residues can also be deduced from the mass spectra.  相似文献   
954.
955.
R Heinz 《Blut》1990,60(2):68-75
The long-term outcome of 116 NHL patients (38 CB, 33 IB, 24 LB, 11 high-grade unclassified, 9 PTCL, 1 Ki-1 lymphoma - see list of abbreviations) treated with an age-adjusted CHOP regimen from 1980-85 was evaluated. The median age was 64 years. Of these patients 28% had significant comorbidity. CB patients had the best outcome; the median survival was not reached after 110 months. However, the differences in survival of all histological entities are not significant (P = 0.08). Fifty-six percent of the patients had clinical stages I-II. The CR rate of all 116 patients was 47%. After a median follow-up of 58 months, 30% of the patients are alive and disease-free. Of 14 relapses 11 occurred within 2 years. The median time period before relapse was 9 months. Salvage therapy failed, as none of the IB and LB patients achieved CR. Five CB patients had CR with second-line therapy, four had PR after induction therapy, one patient relapsed after 30 months. Of the CR patients 15% developed second or third neoplasms. Only one instance of acute myeloblastic leukemia was observed. These results indicate that age-adjusted CHOP is a well-tolerated therapy.  相似文献   
956.
A procedure for the purification of viroid RNA from tomato plants is described which yields up to a milligram of viroid RNA of gel electrophoretic homogeneity within 2 days. This technique is at least three times as fast as previous methods and is generally applicable to other RNA species. Plant material was homogenized and phenol extracted. In a Cs2SO4 density gradient, viroid RNA together with low-molecular-weight RNA, was separated from large single-stranded RNA, DNA, polysaccharides, polyphenols, and other compounds. The separation is based on the differences in the buoyant density and on the selective precipitation of large single-stranded RNA in Cs2SO4. Further purification of viroid RNA was achieved by HPLC over a weak anion exchanger linked to silica gel of optimized pore size. The elution was carried out by a salt gradient with complete exclusion of divalent metal ions. The procedures were applied to whole plants, leaves, stems, roots, cells, and protoplasts. The yields of nucleic acids at the different steps of purification are given for leaves, stems, and roots.  相似文献   
957.
Streptococci of serological groups N and D were found to belong to three different 23S ribosomal RNA (rRNA) homology clusters which are not closely related to each other. One cluster includes the group N streptococci:Streptococcus lactis, S. cremoris, S. diacetylactis, and, in addition, two lactobacilli, Lactobacillus hordniae andL. xylosus. The second one is composed ofStreptococcus faecium, S. durans, andS. faecalis with its subspecies. All are members of serological group D. The third group includes the group D streptococciStreptococcus bovis andS. equinus together withS. thermophilus andS. salivarius. DNA-DNA hybridization studies confirm the close genetic relationship within each of the rRNA homology clusters.  相似文献   
958.
Sixty-six strains ofListeria monocytogenes (as defined in the eighth edition ofBergey's Manual of Determinative Bacteriology) were characterized by DNA relatedness. These strains formed five distinct DNA relatedness groups: (i)L. monocytogenes sensu stricto (30 strains) including the type spain ATCC 15313; (ii) serovar 5 strains (9 strains) corresponding to L. bulgarica; (iii) L. inocua (11 strains of serovars 6a, 6b, 4ab, and undesignated ones) including the reference strains; (iv) six strains of serovars 6a and 6b; (v) ten strains of various serovars. These five groups were clearly distinct fromL. grayi (4 strains) andL. murrayi (3 strains).  相似文献   
959.
Elongation factor Tu (EF-Tu) ofStreptoverticillium mobaraense, which produces pulvomycin, has been prepared to 90% purity. The purified protein differs significantly from the analogous protein found inEscherichia coli in molecular weight and antibiotic sensitivity. EF-Tu migrates in sodium dodecyl sulfate gel electrophoresis as a 46,000-dalton species. The protein is sensitive to pulvomycin, but highly resistant to kirromycin. EF-Tu fromStv. mobaraense exists in multiple forms as monomer and polymers. By contrast to the monomer, the polymers of EF-Tu are completely resistant to pulvomycin.  相似文献   
960.
The purpose of this study was to determine taste difference thresholds for sucrose in frugivorous spider monkeys and omnivorous baboons. Using a two‐bottle preference test of brief duration, we presented four Ateles geoffroyi and four Papio hamdryas anubis with six different reference concentrations (RCs) of 25, 50, 100, 200, 300, and 400 mM sucrose and tested their ability to discriminate these from lower concentrations of this carbohydrate. The just noticeable differences (JNDs), expressed as Weber ratios (Δ/I), were found to range from 0.075–0.25 in the spider monkeys, with a tendency for lower values with higher Rcs. In contrast, the baboons showed the reverse trend, with the lowest Weber ratio of 0.10 at the two lowest Rcs and higher values of up to 0.25 with the highest RC tested. Thus, the JNDs were found to be generally similar in both species and at least as low as in humans. The results support the assumption that both spider monkeys and baboons may use sweetness as a criterion for food selection. The different patterns of differential sensitivity for sucrose across the range of concentrations tested suggest a correlation between the ability to discriminate between different concentrations of sucrose and the dietary habits of the two species. Am. J. Primatol. 48:153–160, 1999. © 1999 Wiley‐Liss, Inc.  相似文献   
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