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showing 10 items of 8115 documents
¿Retorno a las cavernas?
2004
Alternative Biosynthetic Starter Units Enhance the Structural Diversity of Cyanobacterial Lipopeptides
2019
Puwainaphycins (PUWs) and minutissamides (MINs) are structurally analogous cyclic lipopeptides possessing cytotoxic activity. Both types of compound exhibit high structural variability, particularly in the fatty acid (FA) moiety. Although a biosynthetic gene cluster responsible for synthesis of several PUW variants has been proposed in a cyanobacterial strain, the genetic background for MINs remains unexplored. Herein, we report PUW/MIN biosynthetic gene clusters and structural variants from six cyanobacterial strains. Comparison of biosynthetic gene clusters indicates a common origin of the PUW/MIN hybrid nonribosomal peptide synthetase and polyketide synthase. Surprisingly, the biosynthet…
A New Phenanthrene Glycoside and Other Constituents from Dioscorea opposita
2005
Phytochemical investigation of the rhizome of Dioscorea opposita has led to the isolation of a new phenanthrene glycoside, 3,4,6-trihydroxyphenanthrene-3-O-beta-D-glucopyranoside (1), and five known compounds, soyacerebroside I (2), adenosine (3), beta-sitosterol (4), palmitic acid (5) and palmitoyloleoylphosphatidylcholine (6). Their structures were determined by spectroscopic methods, including 1D- and 2D-NMR. Compounds 1-6 exhibited no antifungal activity against the human pathogenic yeasts Candida albicans, C. glabrata and C. tropicalis.
Antifungal steroid saponins from Dioscorea cayenensis.
2004
From the rhizomes of Dioscorea cayenensis Lam.-Holl (Dioscoreaceae), the new 26- O- beta- D-glucopyranosyl-22-methoxy-3 beta,26-dihydroxy-25( R)-furost-5-en-3- O- alpha- L-rhamnopyranosyl-(1-->4)- alpha- L-rhamnopyranosyl-(1-->4)-[ alpha- L-rhamnopyranosyl-(1-->2)]- beta- D-glucopyranoside ( 1) was isolated together with the known dioscin ( 2) and diosgenin 3- O- alpha- L-rhamnopyranosyl-(1-->4)- alpha- L-rhamnopyranosyl-(1-->4)-[ alpha- L-rhamnopyranosyl-(1-->2)]- beta- D-glucopyranoside ( 3). Their structures were established on the basis of spectral data. Compound 2 exhibited antifungal activity against the human pathogenic yeasts Candida albicans, C. glabrata and C. tropicalis (MICs of …
Diversity and Evolution of the Phenazine Biosynthesis Pathway
2010
ABSTRACT Phenazines are versatile secondary metabolites of bacterial origin that function in biological control of plant pathogens and contribute to the ecological fitness and pathogenicity of the producing strains. In this study, we employed a collection of 94 strains having various geographic, environmental, and clinical origins to study the distribution and evolution of phenazine genes in members of the genera Pseudomonas , Burkholderia , Pectobacterium , Brevibacterium , and Streptomyces . Our results confirmed the diversity of phenazine producers and revealed that most of them appear to be soil-dwelling and/or plant-associated species. Genome analyses and comparisons of phylogenies inf…
GNPS-guided discovery of xylacremolide C and D, evaluation of their putative biosynthetic origin and bioactivity studies of xylacremolide A and B
2021
Targeted HRMS2-GNPS-based metabolomic analysis of Pseudoxylaria sp. X187, a fungal antagonist of the fungus-growing termite symbiosis, resulted in the identification of two lipopeptidic congeners of xylacremolides, named xylacremolide C and D, which are built from d-phenylalanine, l-proline and an acetyl-CoA starter unit elongated by four malonyl-CoA derived ketide units. The putative xya gene cluster was identified from a draft genome generated by Illumina and PacBio sequencing and RNAseq studies. Biological activities of xylacremolide A and B were evaluated and revealed weak histone deacetylase inhibitory (HDACi) and antifungal activities, as well as moderate protease inhibition activity …
Recent Trends in the Pharmacological Activity of Isoprenyl Phenolics
2012
Abstract A number of prenylated phenols, mainly flavonoids, have been identified as active constituents of medicinal plants. Due to their beneficial effects on human health, this class of compounds has received a great deal of attention, not only from the pharmaceutical industry, but also from other areas of applied sciences, including the food, brewing, and cosmetics industries. The addition of prenyl residues through the activity of isoprenyltransferases, the key biosynthetic enzymes for these plant metabolites, endows flavonoids with a variety of biological activities, mostly due to improved interaction with membranes and proteins. The role of prenylated flavonoids in plants correlates w…
¿Se acercan los dos Foros?
2002
Effect of nonprotein thiols on protein synthesis in isolated rat hepatocytes.
1996
The ability of nonprotein thiols to modulate rates of protein synthesis was investigated in isolated rat hepatocytes. Addition of cysteine stimulates protein labelling by [14C]Leucine. Glutathione depletion, induced by in vivo administration of L-buthionine sulfoximine and diethylmaleate, did not alter the effect of cysteine, although it decreased the rate of protein synthesis by 32%. The effect of cysteine on protein synthesis does not seem to be related to a perturbation of the redox state of the NAD+/NADH system or to changes in the rate of gluconeogenic pathway. The following observations indicate that cysteine may stimulate protein synthesis by increasing intracellular levels of aspart…
Proteomic evaluation of potentiated sulfa treatment on gilthead sea bream (Sparus aurata L.) liver
2013
Potentiated sulfa drugs are a combination of sulfonamide and pyrimidine potentiators. They are currently used against fish bacterial pathogens in Mediterranean marine fish farming. The present work aimed studying the potential hepatotoxicity of a combination of sulfadiazine (SDZ) and trimethoprim (TMP) in gilthead sea bream juveniles after oral administration, at the recommended ratio of 5: 1 (SDZ/TMP), equivalent to a dose of 30 mg kg(-1) fish day(-1), for 10 days at 19 degrees C temperature. Electrophoresis (DIGE) technology coupled with MS was used to identify possible markers of hepatotoxicity of this treatment. The results obtained show significant changes in the expression of 41 prote…