Steviol (ent-13-hydroxykaur-16-en-19-oic acid)* is metabolized by Gibberella fujikuroi in the presence of inhibitors of gibberellin biosynthesis, such as quaternary ammonium salt-type growth retardants, to afford 7β-Miydroxy- and 6β,7β-dihydroxysteviol, gibberelhns A1, A18, A19, A53 and 7β,13-dihydroxykaurenolide. Steviol acetate (ent-13-acetoxykaur-16-en-19-oic acid) is also metabolized to the 6β,7β-dihydroxy-derivative and to the 13-acetyl derivatives of gibberellins A17 and A20 and steviol methyl ester (methyl ent-13-hydroxykaur-16-en-19-oate) into the monohydroxy-, dihydroxy- and hydroxyoxo-derivatives. These results indicate a low substrate specificity of the enzymes in the fungus and provide a useful preparative methodology of several important plant gibberellins carrying the 13-hydroxyl group. 相似文献
Gibberellin A5 (GA5), a native GA of immature seeds of Pharbitis nil, was fed to Pharbitis nil cell suspension cultures as [C-l, 3H] GA5 (3.1 Ci/mmol), and its metabolism over a 48 hr period was investigated. Radioactivity in free GA metabolites was 13.1%, with 79.9% in GA glucosyl conjugate-like metabolites. Only 7.0% of the radioactivity remained as [3H] GA5. Tentative identifications were based on comparison with retention times of authentic free GAs and/or glucosyl conjugates after sequential chromatography on Si gel partition column → gradient-eluted C18 HPLC-radiocounting (RC) → isocratic-eluted C18 HPLC-RC, and showed that [3H] GA5 was converted to [3H] GA1 (2%), [3H] GA3 (4%), [3H] GA6 (2%), [3H] GA22 (1%) and their glucosyl conjugates, and also to [3H] GA8 glucoside, and [3H] GA5 glucosyl conjugates. The major conjugate-like substances were [3H] GA1 and [3H] GA3 glucosyl esters, at 15% and 34%, respectively, of the total extractable radioactivity. 相似文献
Sixteen triterpenoid glycosides, named S13 to S25, S37, S38 and S40, were isolated from the root of Bupleurum polyclonum Y. Li et S. L. Pan, and their structures were determined from NMR spectral analyses. Among them, S24, S37 and S38 were found to be new substances, their structures being established as 30-β-d-glucopyranosyl 30-hydroxysaikosaponin-b2, 2″-O-acetylsaikosaponin-b2 and 3″-O>-acetylsaikosaponin-b2, respectively. 相似文献
From the immature seeds of Phaseolus vulgaris cv. Kentucky Wonder GA1, GA8, GA38, ABA and GA8 glucoside were isolated, and GA4, GA5, GA6 and GA37 were identified by GC or GC-MS. Unknown substance, AB–II, was also suggested to be present in the immature seeds. In the etiolated seedlings glucosyl esters of GA1 and GA38 were identified by GC. GA8 glucoside and AB–II were shown to be present by the histograms. 相似文献
The egg white, thick and thin fractions, was solubilized in 1.0% SDS solution by vigorous mixing and subjected to gel filtration on a Sepharose 4B column, eluted with 1.0% SDS. The isolated thick and thin ovomucins were found by analytical disc electrophoresis to be free from contamination with lysozyme.
In the velocity sedimentation the two ovomucin fractions behave similarly, both comprising at least two components with sedimentation coefficients 35 S and 30 S.
The chemical compositions of the two ovomucin fractions showed only notable difference in that the carbohydrate content of the thick white ovomucin was somewhat higher than that of the thin white ovomucin. The amino acid profiles of the two fractions were similar.
A comparative study of inhibition on the substrate-incorporation in several species of tumor cells has been achieved in combination with the antibiotics having different action mechanisms. It was thus revealed that a large part of the antitumor antibiotics so far examined showed a marked inhibitory response even at a low concentration. Particularly, the antibiotics whose action mechanism were established primarily on cell membrane were markedly sensitive. An apparent difference in the sensitivity was observed in some groups of antitumor antibiotics which act on nucleic acid synthesis. A methodological survey together with an evaluation of this procedure is discussed. 相似文献
Previous studies have reported an inverse association between height and risk of cardiovascular disease. However, evidence is limited for the association between risk of atherosclerosis and height. Further, although the association between atherosclerosis and body mass index (BMI) is reportedly positive, there have been no reports of studies on associations between height and atherosclerosis in relation to BMI.
Methods
We conducted a cross-sectional study of Japanese men aged 30 to 89 years undergoing general health check-ups.
Results
Of the 1,337 men, 312 were diagnosed with carotid atherosclerosis (carotid intima-media thickness (CIMT) ≥ 1.1 mm), but no significant association was found between height and carotid atherosclerosis for the entire study group. Stratification by BMI status of those analytical findings disclosed a significant inverse association between height and carotid atherosclerosis among overweight (BMI ≥ 25 kg/m2) but not among non-overweight (BMI < 25 kg/m2) men. The classical cardiovascular risk factors-adjusted odds ratio (OR) and 95% confidence interval (CI) of carotid atherosclerosis for an increment of one SD (standard deviation) in height (6.70 cm) were 0.71 (0.54 to 0.94) for overweight (BMI ≥ 25 kg/m2) and 1.05 (0.87 to 1.27) for non-overweight (BMI < 25 kg/m2) men.
Conclusion
Independent from classical cardiovascular risk factors, height was found to be inversely associated with carotid atherosclerosis for overweight but not for non-overweight men. 相似文献
Gut microbiota compositional alteration may have an association with immune dysfunction in patients with Behcet’s disease (BD). We conducted a fecal metagenomic analysis of BD patients. We analyzed fecal microbiota obtained from 12 patients with BD and 12 normal individuals by sequencing of 16S ribosomal RNA gene. We compared the relative abundance of bacterial taxa. Direct comparison of the relative abundance of bacterial taxa demonstrated that the genera Bifidobacterium and Eggerthella increased significantly and the genera Megamonas and Prevotella decreased significantly in BD patients compared with normal individuals. A linear discriminant analysis of bacterial taxa showed that the phylum Actinobacteria, including Bifidobacterium, and the family Lactobacillaceae exhibited larger positive effect sizes than other bacteria in patients with BD. The phylum Firmicutes and the class Clostridia had large effect sizes in normal individuals. There was no significant difference in annotated species numbers (as numbers of operational taxonomic unit; OTU) and bacterial diversity of each sample (alpha diversity) between BD patients and normal individuals. We next assigned each sample to a position using three axes by principal coordinates analysis of the OTU table. The two groups had a significant distance as beta diversity in the 3-axis space. Fecal sIgA concentrations increased significantly in BD patients but did not correlate with any bacterial taxonomic abundance. These data suggest that the compositional changes of gut microbes may be one type of dysbiosis (unfavorable microbiota alteration) in patients with BD. The dysbiosis may have an association with the pathophysiology of BD. 相似文献
Autophagy is an intracellular bulk degradation system. We established mouse fibroblast lines coupling the Tet-off system with an Atg5-/- mouse embryonic fibroblast line to artificially regulate autophagic ability. In the presence of doxycycline (Dox), Atg5 expression was completely suppressed and these cells were autophagy-defective. After removal of Dox, autophagic ability was restored within 6 h. Very low levels of Atg5 could induce an autophagy competent state. We applied this novel system to examine the contribution of autophagy to controlling cell size. Cell size reduction in response to starvation was significantly inhibited in cells unable to undergo autophagy. The generated cell lines will be useful reagents for future mechanistic studies into the regulation and physiologic significance of autophagy. 相似文献