Metallic nanoparticles affect uptake of polycyclic aromatic hydrocarbons and impacts in the Mediterranean mussels Mytilus galloprovincialis.

The impact of metallic nanoparticles (NPs) on the uptake and toxicity of persistent organic pollutants by marine bivalves was assessed through a comparative laboratory study by exposing mussels to polycyclic aromatic hydrocarbon (PAHs), in the presence and absence of ZnO and TiO2 NPs. PAHs and NPs concentration was analyzed after 14 days of exposure in mussels by GC/MS and ICP/AES. Furthermore, impact on the physiology and neurotoxicity of PAHs and NPs acting alone or in mixtures were also determined. Our results confirmed the bio-uptake of PAHs and NPs by mussels. In addition, the exposure NPs-PAHs resulted in different bio-uptake profile to that of PAHs alone. The NPs and accumulation of PAHs led to disturbance of essential metals concentration and to different impact profiles in the filtration and respiration capacities as well as in the acetylcholinesterase activity. Antagonist interactions between NPs and PAHs could occur after exposure.

Changes in Plant Metabolism and Accumulation of Fungal Metabolites in Response to Esca Proper and Apoplexy Expression in the Whole Grapevine.

Trunk diseases have become among the most important grapevine diseases worldwide. They are caused by fungal pathogens that attack the permanent woody structure of the vines and cause various symptoms in woody and annual organs. This study examined modifications of plant responses in green stem, cordon, and trunk of grapevines expressing Esca proper (E) or apoplexy (A) event, which are the most frequent grapevine trunk disease symptoms observed in Europe. Transcript expression of a set of plant defense- and stress-related genes was monitored by quantitative reverse-transcription polymerase chain reaction while plant phytoalexins and fungal metabolites were quantified by high-performance liquid chromatography-mass spectrometry in order to characterize the interaction between the grapevine and trunk disease agents. Expression of genes encoding enzymes of the phenylpropanoid pathway and trans-resveratrol content were altered in the three organs of diseased plants, especially in the young tissues of A plants. Pathogenesis-related proteins and the antioxidant system were severely modulated in A plants, which indicates a drastic stress effect. In the meantime, fungal polyketides 6-MSA, (R)-mellein, and (3R,4R)-4-hydroxymellein, were accumulated in A plants, which suggests their potential effect on plant metabolism during the appearance of foliar symptoms.

Luffa cylindrica and phytosterols bioconversion: from shake flask to jar bioreactor.

Bioconversion of lipophilic compounds poorly soluble in water, such as sterols, required the use of chemicals and solubilizing agents. On the other hand, it was shown that immobilization of Mycobacterium species on the dried fruit of Luffa cylindrica (DFLC) allows a close interaction between immobilized cells and cholesterol particles and increases by then the product's yield. In this work, the use of DFLC in a 5-l jar bioreactor with phytosterols mixture (1 g/l) as substrate was assessed without addition of any chemicals or solubilizing agents. DFLC increased by a factor of four the volumetric productivity of androstenones (0.08 g/l day). Products were accumulated in the aqueous medium while substrates remained on the fibers of DFLC. This observation lets envisage a green semi-continuous process of androstenone production. DFLC has no influence on cell growth, and is moreover natural, inexpensive, non-toxic, and mechanically strong.

Performance of Luffa cylindrica as immobilization matrix in bioconversion reactions by Nicotiana tabacum BY-2.

The dry fruit of Luffa cylindrica was investigated as an immobilization matrix for Nicotiana tabacum cells in bioconversion reactions of exogenous substrates. Immobilized cells show high biocatalytic activity under high substrate levels. Cell growth on the dry fruit can be maintained until reaching an immobilization capacity of 1.8 g cells/g(Luffa).

A new irregular diterpenoid from Opopanax chironium.

The ethereal extract of the roots of Opopanax chironium yielded peucelinenoxide acetate (1), a new natural product with an irregular diterpene skeleton, besides the known coumarins gaudichaudin, columbianadin, peucedanin and officinalin isobutyrate.

Influence of growth conditions on Pseudomonas fluorescens strains: a link between metabolite production and the PLFA profile.

Phospholipid fatty acids (PLFA) are essential constituents of cell membranes. PLFA fingerprints can be used to monitor the impact of growth conditions on bacteria because the fatty acid composition is closely linked to the growth environment. Through statistical analyses, clusters can be shown connecting the PLFA of Pseudomonas fluorescens with the growth condition. The metabolite production/excretion by bacteria is shown to be related to such clusters. This suggests that modification of the cell membrane, due to the variations in the fatty acid composition, is linked to the presence of metabolites in the bacterial culture media.

Germacranolides from seeds of the endangered Umbelliferae species Rouya polygama.

From the etheral extract of Rouya polygama Coincy seeds (Umbelliferae) six new germacranolides 1-6 were isolated. The structures were elucidated by chemical methods and spectroscopic analysis. Compounds 1 and 4 exhibited activity against Artemia salina larvae.

Structure and absolute stereochemistry of phormidolide, a new toxic metabolite from the marine cyanobacterium Phormidium sp.

The extract from a laboratory culture of an Indonesian isolate of the cyanobacterium Phormidium sp. displayed inhibitory activity in a Ras-Raf protein interaction assay. Assay-guided fractionation led to the isolation of both active and inactive materials of novel structure. The major inactive metabolite, phormidolide, was nevertheless highly toxic to brine shrimp (LC(50) = 1.5 microM), and hence, its structure was elucidated using various spectroscopic methods, primarily NMR. A series of partial structures were developed from standard experiments and then assembled using GHMBC, 2D INADEQUATE, and ACCORD-ADEQUATE data obtained on a (13)C-enriched sample. The relative stereochemistry at phormidolide's 11 chiral centers was established using the J-based configuration analysis method in concert with the G-BIRD(R)-HSQMBC NMR experiment. Absolute stereochemistry was determined on a bis-acetonide derivative using the variable temperature Mosher ester method. The robust number of NMR restraints provided from determination of most homonuclear and heteronuclear coupling constants in phormidolide, along with an abundance of NOE information, allowed construction of a refined lowest energy three-dimensional structure in Macromodel. Phormidolide is one of only a few macrolide-type natural products to be reported from marine cyanobacteria.