1,721,018 research outputs found
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
Autoinhibitory sterol sulfates mediate programmed cell death in a bloom-forming marine diatom
No full textCell mortality is a key mechanism that shapes phytoplankton blooms and species dynamics in aquatic environments. Here we show that sterol sulfates (StS) are regulatory molecules of a cell death program in Skeletonema marinoi, a marine diatom-blooming species in temperate coastal waters. The molecules trigger an oxidative burst and production of nitric oxide in a dose-dependent manner. The intracellular level of StS increases with cell ageing and ultimately leads to a mechanism of apoptosis-like death. Disrupting StS biosynthesis by inhibition of the sulfonation step significantly delays the onset of this fatal process and maintains steady growth in algal cells for several days. The autoinhibitory activity of StS demonstrates the functional significance of small metabolites in diatoms. The StS pathway provides another view on cell regulation during bloom dynamics in marine habitats and opens new opportunities for the biochemical control of mass-cultivation of microalgae
Antifungal 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
Profiling of complex lipids in marine microalgae by UHPLC/tandem mass spectrometry
No full textMicroalgal lipids are of great interest for their potential as food and feed ingredients, nutraceutical and cosmetic components, and as source of energy. Glycerol-based lipids can constitute up to 50% or more of the biomass of microalgae. How synthesis of these products takes place is still poorly explored, although remarkable differences with plants and among microalgal species have already emerged. These differences attain to both lipid class and fatty acyl composition, which could bemodulated by specific growth conditions. Here we present a new method based on UHPLC coupled to high resolution tandem mass spectrometry for targeted analysis of the main lipid classes, i.e., glycolipids, phospholipids and triacylglycerols, applied to five marine microalgae exhibiting a great diversity in lipid composition. The LC/MS/MS approach is integrated with a recently proposed MTBE-based protocol for lipid extraction and the entire workflow is of general application to lipid profiling of cell extracts from different sources. (C) 2016 Elsevier B.V. All rights reserved
Capnophilic lactic fermentation from Thermotoga neapolitana: A resourceful pathway to obtain almost enantiopure L-lactic acid
Full text linkChemical Synthesis of Marine-Derived Sulfoglycolipids, a New Class of Molecular Adjuvants
No full textVaccines play a primary role in the protection of human health by preventing infectious and chronic diseases. Recently we have reported 1,2-O-distearoyl-3-O-beta-D-sulfoquinovosylglycerol (beta-SQDG18), here named Sulfavant A (1), which shows promising properties as a new molecular adjuvant in in vitro and in vivo tests. In the present manuscript, we provide full details about a synthetic strategy for the preparation of 1, including a discussion of chemical determinants of the activity and the major technical hurdles we faced during the study. Synthesis of Sulfavant A (1) is achieved by a versatile procedure based on a trichloroacetimidate methodology and peracetate sugar precursors. The final design opens possibilities for the preparation of a series of interesting analogs for further pharmacological optimization and development, including derivatives containing different saturated and polyunsaturated fatty acids (e.g., 17 and 22)
The Marine Dinoflagellate Alexandrium minutum Activates a Mitophagic Pathway in Human Lung Cancer Cells
No full textMarine dinoflagellates are a valuable source of bioactive molecules. Many species produce cytotoxic compounds and some of these compounds have also been investigated for their anticancer potential. Here, we report the first investigation of the toxic dinoflagellate Alexandrium minutum as source of water-soluble compounds with antiproliferative activity against human lung cancer cells. A multi-step enrichment of the phenol-water extract yielded a bioactive fraction with specific antiproliferative effect (IC50 = 0.4 mu gmL(-1)) against the human lung adenocarcinoma cells (A549 cell line). Preliminary characterization of this material suggested the presence of glycoprotein with molecular weight above 20 kDa. Interestingly, this fraction did not exhibit any cytotoxicity against human normal lung fibroblasts (WI38). Differential gene expression analysis in A549 cancer cells suggested that the active fraction induces specific cell death, triggered by mitochondrial autophagy (mitophagy). In agreement with the cell viability results, gene expression data also showed that no mitophagic event was activated in normal cells WI38
Exploring the chemical diversity in marine organisms: new molecules for pharmaceutical applications
Full text link2010 - 2011It is increasingly recognized that the oceans preserve a huge number of natural products and novel chemical entities, with biological activities that may be useful in the quest for finding drugs with greater efficacy and specificity for the treatment of many human diseases. In this light, the aim of my project was to isolate and characterize novel molecules from marine organisms with regard to the identification of new “lead compounds” for pharmaceutical applications. The organisms considered for this study were selected by using two different strategies. The first one was based on enhancement of the taxonomic diversity. In this process, an emphasis was placed on collecting specimens related to - but differing from - those known to contain bioactive natural products. The second approach was to evaluate ecological factors such as costumer pressure, growth form (e.g. thin encrusting), level of resource competition, presence or absence of biofouling, etc., and relate this to the expression of the secondary metabolism. Some invasive species have chemical defences, which may enhance their invasion success, so as many marine organisms are soft bodied and have a sedentary life style necessitating chemical means of defence. Therefore, they have evolved the ability to synthesize or to obtain from marine microorganisms bioactive compounds that help them in deterring predators, keep competitors at bay or paralyze their prey. [edited by the author]X n.s
ADViSELipidomics: a workflow for analyzing lipidomics data
Full text linkADViSELipidomics is a novel Shiny app for preprocessing, analyzing, and visualizing lipidomics data. It handles the outputs from LipidSearch and LIQUID for lipid identification and quantification and the data from the Metabolomics Workbench. ADViSELipidomics extracts information by parsing lipid species (using LIPID MAPS classification) and, together with information available on the samples, performs several exploratory and statistical analyses. When the experiment includes internal lipid standards, ADViSELipidomics can normalize the data matrix, providing normalized concentration values per lipids and samples. Moreover, it identifies differentially abundant lipids in simple and complex experimental designs, dealing with batch effect correction. Finally, ADViSELipidomics has a user-friendly Graphical User Interface (GUI) and supports an extensive series of interactive graphics
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