Impacts of tree canopy structure on wind flows and fire propagation simulated with FIRETEC

Introduction   

Forest fuel management in the context of fire prevention generally induces heterogeneous spatial patterns of vegetation. However, the impact of the canopy structure on both wind flows and fire behavior is not well understood.     

Origin of French virgin olive oil registered designation of origins predicted by chemometric analysis of synchronous excitation-emission fluorescence spectra

The authentication of virgin olive oil samples requires usually the use of sophisticated and very expensive analytical techniques, so there is a need for fast and inexpensive analytical techniques for use in a quality control methodology. Virgin olive oils present an intense fluorescence spectra. Synchronous excitation-emission fluorescence spectroscopy (SEEFS) was assessed for origin determination of virgin olive oil samples from five French registered designation of origins (RDOs) (Nyons, Vallée des Baux, Aix-en-Provence, Haute-Provence, and Nice). The spectra present bands between 600 and 700 nm in emission due to chlorophylls a and b and pheophytins a and b. The bands between 275 and 400 nm in emission were attributed to alpha-, beta-, and gamma-tocopherols and to phenolic compounds, which characterize the virgin olive oils compared to other edible oils. The chemometric treatment (PLS1) of synchronous excitation-emission fluorescence spectra allows one to determine the origin of the oils from five French RDOs (Baux, Aix, Haute-Provence, Nice, and Nyons). Results were quite satisfactory, despite the similarity between two denominations of origin (Baux and Aix) that are composed by some common cultivars (Aglandau and Salonenque). The interpretation of the regression coefficients shows that RDOs are correlated to chlorophylls, pheophytins, tocopherols, and phenols compounds, which are different for each origin. SEEFS is part of a global analytic methodology that associates spectroscopic and chromatographic techniques. This approach can be used for traceability and vindicates the RDOs.     

Effect of breed and gender on bovine liver cytochrome P450 3A (CYP3A) expression and inter-species comparison with other domestic ruminants

The cytochrome P450 (P450) superfamily represents a group of relevant enzymes in the field of drug metabolism and several exogenous or constitutional factors contribute to regulate its expression. Cattle represent an important source of animal-derived food-products and studies concerning the P450 expression are needed for the extrapolation of pharmacotoxicological data from one species to another and for the evaluation of the consumer's risk associated with the consumption of harmful residues found in foodstuffs. In the present study, possible breed-, gender- and species-differences in P4503A (the P450 subfamily more expressed in the human liver) expression were studied in vitro in Piedmontese (PDM) and Limousin (LIM) meat cattle breeds of both sexes and in domestic Ruminants (cattle, sheep and goats). Cytochrome P450 and P4503A contents as well as CYP3A-dependent drug metabolising enzymes (DME) were measured in liver microsomes. Significant lower levels of P450 (P < 0.001) and P4503A (P < 0.05) contents were observed in PDM vs. LIM of both sexes; the P4503A-dependent DME activities were significantly (P values ranging from 0.05 up to 0.001) higher in PDM cattle, particularly in males. A gender-effect in DME activities was noticed (P < 0.05) only in PDM male cattle. With regards to the species, the expression of both P4503A apoprotein and some of the related DME activities were more pronounced in sheep (P < 0.01 vs. cattle) and in goats (P < 0.05 vs. sheep; P < 0.01 vs. cattle) than in cattle. The significant differences in P4503A expression observed in LIM and PDM cattle are consistent with previously published data on strain- and breed-differences pointed out in rats and men. As far as a possible sex-effect is concerned, no clear-cut evidence is likely to be drawn. Finally, P4503A expression was more relevant in small ruminants.     

Lack of Sex-influence on the In Vitro Metabolism of Ivermectin by Hepatic Microsomal Preparations from Cattle

Veterinary Research Communications -     

The interaction between moxidectin and MDR transporters in primary cultures of rat hepatocytes

The interaction of moxidectin (a macrocyclic lactone, ML) with P-glycoprotein (P-gp), multidrug resistance associated proteins (MRPs) and breast cancer resistance protein (BCRP) was studied in primary cultures of rat hepatocytes by measuring the intracellular accumulation of [14C]-moxidectin over 72 h in the presence of specific inhibitors: for P-gp, verapamil (10 microM); for MRPs, MK571 (100 microM), indomethacin (10 microM) and probenecid (3.8 mM); and for BCRP, fumitremorgin C (5 microM). The P-gp and MRP inhibitors increased significantly (P < 0.01) by 48.7%, 49.8%, 49.9% and 57.2% the area under the time-intracellular concentration curve (AUC) of moxidectin in rat hepatocytes, while the BCRP inhibitor, fumitremorgin C, had no effect on the AUC compared with the control. In addition, the mRNAs of all the drug transporters studied were detected in rat hepatocytes from 0 to 72 h. Using this cellular model it has been shown that MRP inhibitors increase moxidectin intracellular concentrations to a similar extent as the P-gp inhibitor. The identification of all the transporters that interact with MLs remains a challenge, which currently concerns several important therapeutic fields.     

A transgenic model for listeriosis: role of internalin in crossing the intestinal barrier

Listeria monocytogenes is responsible for severe food-borne infections, but the mechanisms by which bacteria cross the intestinal barrier are unknown. Listeria monocytogenes expresses a surface protein, internalin, that interacts with a host receptor, E-cadherin, to promote entry into human epithelial cells. Murine E-cadherin, in contrast to guinea pig E-cadherin, does not interact with internalin, excluding the mouse as a model for addressing internalin function in vivo. In guinea pigs and transgenic mice expressing human E-cadherin, internalin was found to mediate invasion of enterocytes and crossing of the intestinal barrier. These results illustrate how relevant animal models for human infections can be generated.     

Minimizing the Treatments Required to Determine the Responses of Different Crop Genotypes to Potassium Supply

ABSTRACT

Crop genotypes that make best use of potassium (K) fertilizers can promote agricultural sustainability. However, screening germplasm collections for responses to K fertilizers is often laborious and expensive. To reduce costs, the number of K fertilizer treatments required to identify better genotypes should be minimized. This might be achieved by exploiting the mathematical relationships between biomass, plant K content, and K supply. This study employed 14 barley (Hordeum vulgare L.) genotypes growing in a hydroponics system that allowed the K supply to roots to be controlled through the K concentration in a flowing solution. It sought to determine the minimal number of treatments required to model the relationships between (a) shoot biomass and K supply, (b) plant K content and K supply, and (c) shoot biomass and plant K content. The relationships between (a) shoot biomass and K supply and (b) plant K content and K supply for any given genotype could be fitted by Michaelis–Menten equations and each of these could be estimated from data obtained at two, appropriately-chosen, rates of K supply. The relationship between shoot biomass and plant K content could be estimated from these relationships. However, the optimum K supply required for accurate estimates differed between genotypes and whether shoot biomass or plant K content was to be estimated. It is, therefore, suggested that the relationships between shoot biomass, plant K content, and K supply might best be determined from measurements of biomass and K content at three, carefully-selected, rates of K supply.