A marine-derived strain of Clonostachys rosea isolated from sediments of the river Loire estuary (France) was investigated for its high lipid production. The fungal strain was grown on six different culture media to explore lipid production changes. An original branched conjugated fatty acid, mainly present in triglycerides and mostly produced when grown on DCA (23% of total fatty acid composition). It was identified as 4-Me-6E,8E-hexadecadienoic on the basis of spectroscopic analyses. This fatty acid reduced viability of MCF-7 breast cancer cells in a dose dependent manner (up to 63%) at physiological free fatty acid human plasma concentration (100 μM). Reduction of gene expression of two lipogenic enzymes, the acetyl CoA carboxylase (ACC) and the fatty acid synthase (FAS) was evaluated to explore the mechanisms of action of 4-Me-6E,8E-16:2 acid. At 50 μM, 50% and 35% of mRNA gene expression inhibition were observed for ACC and FAS, respectively.

The marine sponge, Axinyssa djiferi, collected on mangrove tree roots in Senegal, was investigated for glycolipids. A mixture containing new glycosphingolipids, named axidjiferoside-A, -B and -C, accounted for 0.07% of sponge biomass (dry weight) and for 2.16% of total lipids. It showed a significant antimalarial activity, with a 50% inhibitory concentration (IC₅₀) of 0.53 ± 0.2 μM against a chloroquine-resistant strain of Plasmodium falciparum. They were identified as homologous β-galactopyranosylceramides composed of 2-amino-(6E)-octadec-6-en-1,3,4-triol, and the major one, axidjiferoside-A (around 60%), contained 2-hydroxytetracosanoic acid. Cytotoxicity was studied in vitro on human cancer cell lines (multiple myeloma, colorectal adenocarcinoma, glioblastoma and two lung cancer NSCLC-N6 and A549). Results of this investigation showed that axidjiferosides are of interest, because they proved a good antiplasmodial activity, with only a low cytotoxicity against various human cell lines and no significant antitrypanosomal and antileishmanial activity. Thus, it seems that galactosylceramides with a β anomeric configuration may be suitable in searching for new antimalarial drugs.

The most common sterol in fungi is ergosterol, which has frequently been investigated in human pathogenic fungal strains. This sterol, and others isolated from fungal strains, has also demonstrated cytotoxicity against cancer cell lines and antimicrobial activities. Marine fungi can produce high amounts of bioactive compounds. So, a screening was performed to study sterol composition using GC/MS in 19 marine fungal strains and ergosterol was always the major one. One strain, Clonostachys rosea MMS1090, was selected due to its high amount of eburicol and a one strain many compounds approach was performed on seven culture media to optimize its production. After purification and structural identification by NMR, eburicol was assessed against four cancer cell lines, MCF-7, MDA-MB-231, NSCLC-N6-L16 and A549, and seven human pathogenic bacteria Staphylococcus aureus, Bacillus sp., Bacillus cereus, Listeria ivanovii, Escherichia coli, Citrobacter freundii and Salmonella spp. The most significant activity was cytotoxicity against MCF-7 cells (2 µM). This is the first report of such an accumulation of eburicol in the marine fungal strain C. rosea confirming its potential in the production of bioactive lipids.

Microalgae provide valuable bio-components with economic and environmental benefits. The monitoring of microalgal production is mostly performed using different sensors and analytical methods that, although very powerful, are limited to qualified users. This study proposes an automated Raman spectroscopy-based sensor for the online monitoring of microalgal production. For this purpose, an in situ system with a sampling station was made of a light-tight optical chamber connected to a Raman probe. Microalgal cultures were routed to this chamber by pipes connected to pumps and valves controlled and programmed by a computer. The developed approach was evaluated on Parachlorella kessleri under different culture conditions at a laboratory and an industrial algal platform. As a result, more than 4000 Raman spectra were generated and analysed by statistical methods. These spectra reflected the physiological state of the cells and demonstrate the ability of the developed sensor to monitor the physiology of microalgal cells and their intracellular molecules of interest in a complex production environment.

Background: Nowadays, the efficiency of antibiotics is endangered by the development of resistant bacterial strains. Consequently, novel bioactive agents are intensively searched. Marine sponges are well-known for being major sources of bioactive compounds, including unusual sterols. Until now, among sterols, noteworthy antibacterial activity has been reported exclusively for Δ5 sterols. Objectives: This study aims to describe the steroid composition of the marine sponge Biemna laboutei collected in the North coast of Madagascar, and the antibacterial activity of steroid mixture against human pathogenic strains. Methods: Sponge was extracted in CHCl₃/MeOH. Free steroids were separated from other lipids by column chromatography with dichloromethane as specific eluent. Free sterols/steroids and sterol acetates were analysed by gas chromatography coupled with mass spectrometry. Antibacterial activity of steroid fractions was assessed for eight strains using agar diffusion with cellulose disks. Results: Neutral lipids were the major lipid class (79.1% of total lipids). The dichloromethane eluted fraction contained only free steroids giving rise to the identification of eleven compounds. These components presented exclusively Δ7 unsaturation, including lathosterol as the major one (38.4%) and four 3-oxo-steroids (11.8%). The steroid fraction of B. laboutei has exhibited inhibitory activity against pathogenic strains but more particularly against gram(+) Bacillus cereus (MIC of 12.5 μg/mL) and Staphylococcus aureus (MIC of 25 μg/mL) strains. This latter bacterium causes several illnesses, some of those strains being antibiotic-resistant and this becomes a worldwide health problem. Conclusion: This is the first report for an antibacterial activity of a mixture of Δ7 steroids against a resistant strain of S. aureus to many antibiotics.