1,721,005 research outputs found
Glycolipids synthesis: improved hydrazinolysis conditions for preparation of 1,2-polyunsaturated fatty acyl-beta-monogalactosyl-glycerols
No full textThe investigation is related to the development of a general strategy for the synthesis of glycolipids including analogs bearing polyunsaturated fatty acids. In particular, here we report exceptionally mild and selective conditions to remove acetate protecting groups from glyceroglycolipids by hydrazinolysis. Synthetic 1,2-O-di-arachidonoyl-3-O-beta-galactosyl-glycerol was used as representative of polyunsaturated beta-galactosyl-di-acyl-glycerols due to its reactivity under the conditions usually employed in literature. (C) 2016 Elsevier Ltd. All rights reserved
Distribution of granuloside in the Antarctic nudibranch Charcotia granulosa (Gastropoda: Heterobranchia: Charcotiidae)
No full textThe loss of the shell in nudibranch gastropods has been related to the acquisition of chemical defensive strategies during evolution, such as the use of natural products to deter predation. In the present study, we investigated the origin, location, and putative role of granuloside (1), a homosesterterpene lactone, recently isolated from the Antarctic nudibranch Charcotia granulosa Vayssisre, 1906. Several adults, egg masses, and its bryozoan prey, Beania erecta Waters, 1904, were chemically analyzed by chromatographic and spectroscopic techniques. Light-and transmission electron microscopy of the mantle revealed complex glandular structures, which might be associated with the storage of defensive compounds in analogy to mantle dermal formations described in other nudibranchs. Although preliminary in situ repellence bioassays with live specimens of the nudibranch showed avoidance against the Antarctic generalist sea star predator Odontaster validus, the specific role of the terpene granuloside requires further investigation. The egg masses do not present granuloside, and the glandular structures are absent in the trochophore larvae. Our results suggest that C. granulosa synthesizes granuloside de novo in early stages of its ontogeny, instead of obtaining it from the prey. Considering the wide geographic area inhabited by this slug, this may be advantageous, because natural products produced by the slug will not be affected by fluctuant food availability. Overall, the Antarctic sea slug C. granulosa seems to possess defensive strategies that are similar, in terms of production and storage, to nudibranchs from other regions of the world. This species is one of the few cladobranchs investigated so far that present de novo biosynthesis of a defensive compound
Exiguapyrone and exiguaone, new polypropionates from the Mediterranean cephalaspidean mollusc Haminoea exigua
No full textTwo new polypropionates, named exiguapyrone (2) and exiguaone (3) along with the known haminol-1 (4) and -2 (5), have been isolated from the lipidic extract of the Mediterranean cephalaspidean mollusc Haminoea exigua. The regular propionate skeletons, structurally related to other polypropionates from the congener Haminoea fusari, have been elucidated by means of NMR techniques as natural (2 and 3) and alpha-/gamma-pyrone methyl derivatives (2a and 2b). This is a further report showing the co-occurrence of alkyl-pyridines and polypropionates in Haminoea molluscs strengthening the role of polypropionates as chemical markers among cephalaspideans. (C) 2015 Elsevier Ltd. All rights reserved
The Missing Piece in Biosynthesis of Amphidinols: First Evidence of Glycolate as a Starter Unit in New Polyketides from Amphidinium carterae
No full textTwo new members of the amphidinol family, amphidinol A (1) and its 7-sulfate derivative amphidinol B (2), were isolated from a strain of Amphidinium carterae of Lake Fusaro, near Naples (Italy), and chemically identified by spectroscopic and spectrometric methods. Amphidinol A showed antifungal activity against Candida albicans (MIC = 19 mu g/mL). Biosynthetic experiments with stable isotope-labelled acetate allowed defining the elongation process in 1. For the first time the use of glycolate as a starter unit in the polyketide biosynthesis of amphidinol metabolites was unambiguously demonstrated
Uso e preparazione di glicolipidi come adiuvanti in vaccini, Brevetto US Patent 20,160,151,483, 2016
No full textAntifungal Amphidinol 18 and Its 7-Sulfate Derivative from the Marine Dinoflagellate Amphidinium carterae
No full textTwo new polyketides of the amphidinol family, amphidinol 18 (wAM18, 1) and its corresponding 7-sulfate derivative (AM19, 2), have been isolated from the MeOH extract of the dinoflagellate Amphidinium carterae. Structure elucidation of the two polyoxygenated molecules has been accomplished by extensive use of spectroscopic and spectrometric techniques. AM18 exhibited antifungal activity against Candida albicans at 9 mu g/mL
An improved UPLC-MS/MS platform for quantitative analysis of glycerophosphoinositol in mammalian cells.
No full textThe glycerophosphoinositols constitute a class of biologically active lipid-derived mediators whose intracellular levels are modulated during physiological and pathological cell processes. Comprehensive assessment of the role of these compounds expands beyond the cellular biology of lipids and includes rapid and unambiguous measurement in cells and tissues. Here we describe a sensitive and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantitative analysis of the most abundant among these phosphoinositide derivatives in mammalian cells, the glycerophosphoinositol (GroPIns). The method has been developed in mouse Raw 264.7 macrophages with limits of quantitation at 3 ng/ml. Validation on the same cell line showed excellent response in terms of linear dynamic range (from 3 to 3,000 ng/ml), intra-day and inter-day precision (coefficient of variation ≤ 7.10%) and accuracy (between 98.1 and 109.0%) in the range 10-320 ng/ml. As proof of concept, a simplified analytical platform based on this method and external calibration was also tested on four stimulated and unstimulated cell lines, including Raw 264.7 macrophages, Jurkat T-cells, A375MM melanoma cells and rat basophilic leukemia RBL-2H3 cells. The results indicate a wide variation in GroPIns levels among different cell lines and stimulation conditions, although the measurements were always in line with the literature. No significant matrix effects were observed thus indicating that the here proposed method can be of general use for similar determinations in cells of different origin
Isolamento, caratterizzazione strutturale e sintesi di nuovi potenziali feromoni d'allarme dal mollusco marino Scaphander Lignarius
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