http://www.mdpi.com/journal/marinedrugs/special_issues/marine-lipids/ Dear Colleagues, Marine lipids are undoubtly representatives of the marine chemical biodiversity. Fatty acids (FA) and lipid-containing FA are ubiquitous in nature and a number of structures occur in both terrestrial and marine organisms, but the latter organisms have proved to be a major source of unique structures. From this point of view, the most primitive animals, such as sponges and gorgonians, seem to be of great interest. Thus, in addition to the very important polyunsaturated FA such as eicosapentaenoic and docosahexaenoic acids, a great number of various FA occur in marine organisms ranged from bacteria and first planktonic marine producers to fish, including branched, non-methylene-interrupted, conjugated, hydroxylated, methoxylated and halogenated FA. These unique lipids originate from unusual biosynthetic pathways. Furthermore, oxylipins, phospholipids and glycolipids have considerable importance and will be taken into account, especially the latter compounds that excite increasing interest regarding their promising antitumor and immunomodulating activities. The biomedical potential of marine lipids leads to an intense effort of research. The chemotaxonomic value of certain lipid molecules would be also taken into account including FA and sterols. This special issue of Marine Drugs is devoted to “Marine Lipids”. The aim of this issue is to present the recent advances and to introduce some important future research directions in the field of research. Thus, we hope that the manuscripts here included will cover a number of aspects of recent developments within this field. Prof. Dr. Gilles Barnathan Guest Editor {snippet name="submission_info"} http://www.mdpi.com/1660-3397/8/12/2988/ The starfish Narcissia canariensis harvested from the coasts off Dakar, Senegal, was investigated for glycolipids (GL). This report deals with the isolation, characterization and biological activity of a fraction F13-3 separated from the GL mixture and selected according to its ability to inhibit KB cell proliferation after 72 hours of treatment. Firstly, a GL mixture F13 was obtained that accounted for 1.36% of starfish biomass (dry weight) and 0.36% of total lipids. The fraction F13-3 obtained from F13 contained three homologous GL identified as peracetylated derivatives on the basis of chemical and spectroscopic evidence. These contained a β-glucopyranoside as sugar head, a 9-methyl-branched 4,8,10-triunsaturated long-chain aminoalcohol as sphingoid base and amide-linked 2-hydroxy fatty acid chains. The majority (63%) had an amide-linked 2‑hydroxydocosanoic acid chain and was identified as the ophidiacerebroside-C, firstly isolated from the starfish Ophidiaster ophidiamus. The minor components of F13-3 differed by one more or one less methylene group, and corresponded to ophidiacerebroside-B and -D. We found that F13-3 displayed an interesting cytotoxic activity over 24 hours on various adherent human cancerous cell lines (multiple myeloma, colorectal adenocarcinoma and glioblastoma multiforme) with an IC50 of around 20 μM. http://www.mdpi.com/1660-3397/8/12/2988/ Wed, 22 Dec 2010 00:00:00 CET Marine Drugs 2010-12-22 8 12 Article 2988 2998 1660-3397 Cytotoxicity on Human Cancer Cells of Ophidiacerebrosides Isolated from the African Starfish Narcissia canariensis 2010-12-22 doi: 10.3390/md8122988 Fereshteh Farokhi Gaetane Wielgosz-Collin Monique Clement Jean-Michel Kornprobst Gilles Barnathan http://www.mdpi.com/1660-3397/8/12/2961/ The sponge Fascaplysinopsis sp. (order Dictyoceratida, Family Thorectidae) from the west coast of Madagascar (Indian Ocean) is a particularly rich source of bioactive nitrogenous macrolides. The previous studies on this organism led to the suggestion that the latter should originate from associated microsymbionts. In order to evaluate the influence of microsymbionts on lipid content, 10 samples of Fascaplysinopsis sp. were investigated for their sterol composition. Contrary to the secondary metabolites, the sterol patterns established were qualitatively and quantitatively stable: 14 sterols with different unsaturated nuclei, D5, D7 and D5,7, were identified; the last ones being the main sterols of the investigated sponges. The chemotaxonomic significance of these results for the order Dictyoceratida is also discussed in the context of the literature. The conjugated diene system in D5,7 sterols is known to be unstable and easily photo-oxidized during storage and/or experiments to produce 5a,8a-epidioxy sterols. However, in this study, no 5a,8a-epidioxysterols (or only trace amounts) were observed. Thus, it was supposed that photo-oxidation was avoided thanks to the natural antioxidants detected in Fascaplysinopsis sp. by both the DPPH and b-caroten bleaching assays. http://www.mdpi.com/1660-3397/8/12/2961/ Fri, 17 Dec 2010 00:00:00 CET Marine Drugs 2010-12-17 8 12 Article 2961 2975 1660-3397 Sterols from the Madagascar Sponge Fascaplysinopsis sp. 2010-12-17 doi: 10.3390/md8122961 Maurice Aknin Emmanuelle Gros Jean Vacelet Yoel Kashman Anne Gauvin-Bialecki http://www.mdpi.com/1660-3397/8/10/2597/ The effect of marine polyunsaturated fatty acids on biofilm formation by the human pathogens Candida albicans and Candida dubliniensis was investigated. It was found that stearidonic acid (18:4 n-3), eicosapentaenoic acid (20:5 n-3), docosapentaenoic acid (22:5 n-3) and docosahexaenoic acid (22:6 n-3) have an inhibitory effect on mitochondrial metabolism of both C. albicans and C. dubliniensis and that the production of biofilm biomass by C. dubliniensis was more susceptible to these fatty acids than C. albicans. Ultrastructural differences, which may be due to increased oxidative stress, were observed between treated and untreated cells of C. albicans and C. dubliniensis with formation of rough cell walls by both species and fibrillar structures in C. dubliniensis. These results indicate that marine polyunsaturated fatty acids may be useful in the treatment and/or prevention of biofilms formed by these pathogenic yeasts. http://www.mdpi.com/1660-3397/8/10/2597/ Fri, 08 Oct 2010 00:00:00 CEST Marine Drugs 2010-10-08 8 10 Article 2597 2604 1660-3397 Effect of Marine Polyunsaturated Fatty Acids on Biofilm Formation of Candida albicans and Candida dubliniensis 2010-10-08 doi: 10.3390/md8102597 Vuyisile S. Thibane Johan L. F. Kock Ruan Ells Pieter W. J. van Wyk Carolina H. Pohl http://www.mdpi.com/1660-3397/8/10/2569/ The well-known fatty acids with a D5,9 unsaturation system were designated for a long period as demospongic acids, taking into account that they originally occurred in marine Demospongia sponges. However, such acids have also been observed in various marine sources with a large range of chain-lengths (C16–C32) and from some terrestrial plants with short acyl chains (C18–C19). Finally, the D5,9 fatty acids appear to be a particular type of non-methylene-interrupted fatty acids (NMA FAs). This article reviews the occurrence of these particular fatty acids in marine and terrestrial organisms and shows the biosynthetic connections between D5,9 fatty acids and other NMI FAs. http://www.mdpi.com/1660-3397/8/10/2569/ Fri, 08 Oct 2010 00:00:00 CEST Marine Drugs 2010-10-08 8 10 Review 2569 2577 1660-3397 Demospongic Acids Revisited 2010-10-08 doi: 10.3390/md8102569 Jean-Michel Kornprobst Gilles Barnathan http://www.mdpi.com/1660-3397/8/7/2175/ Alkylglycerols (alkyl-Gro) are ether lipids abundant in the liver of some elasmobranch fish species such as ratfishes and some sharks. Shark liver oil from Centrophorus squamosus (SLO), or alkyl-Gro mix from this source, have several in vivo biological activities including stimulation of hematopoiesis and immunological defences, sperm quality improvement, or anti-tumor and anti-metastasis activities. Several mechanisms are suggested for these multiple activities, resulting from incorporation of alkyl-Gro into membrane phospholipids, and lipid signaling interactions. Natural alkyl-Gro mix from SLO contains several alkyl-Gro, varying by chain length and unsaturation. Six prominent constituents of natural alkyl-Gro mix, namely 12:0, 14:0, 16:0, 18:0, 16:1 n-7, and 18:1 n-9 alkyl-Gro, were synthesized and tested for anti-tumor and anti-metastatic activities on a model of grafted tumor in mice (3LL cells). 16:1 and 18:1 alkyl-Gro showed strong activity in reducing lung metastasis number, while saturated alkyl-Gro had weaker (16:0) or no (12:0, 14:0, 18:0) effect. Multiple compounds and mechanisms are probably involved in the multiple activities of natural alkyl-Gro. http://www.mdpi.com/1660-3397/8/7/2175/ Mon, 19 Jul 2010 00:00:00 CEST Marine Drugs 2010-07-19 8 7 Review 2175 2184 1660-3397 Multiple Beneficial Health Effects of Natural Alkylglycerols from Shark Liver Oil 2010-07-19 doi: 10.3390/md8072175 Anne-Laure Deniau Paul Mosset Frédérique Pédrono Romain Mitre Damien Le Bot Alain B. Legrand