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Aims: Exploitation of natural biodiversity in species Pycnoporus coccineus and Pycnoporus sanguineus to screen for a new generation of laccases with properties suitable for the lignin-processing sector. Methods and Results: Thirty strains originating from subtropical and tropical environments, mainly isolated from fresh specimens collected in situ, were screened for laccase activity. On the basis of levels of enzyme activity and percentage of similarity between protein sequences, the laccases from strains BRFM 938, BRFM 66 and BRFM 902 were selected for purification and characterization. Each BRFM 938, BRFM 66 and BRFM 902 laccase gene encoded a predicted protein of 518 amino acids; the three deduced proteins showed 68·7–97·5% similarity with other Polyporale laccases. The three laccases (59·5–62·9 kDa with 7–10% carbohydrate content) had high redox potentials (0·72–0·75 V vs normal hydrogen electrode at pH 6), remained highly stable up to 75–78°C and at pH 5–7 mixtures, and were resistant to methyl and ethyl alcohols, acetonitrile and dimethylsulfoxide at concentrations as high as 50% (v/v). The best laccase-1-hydroxybenzotriazole systems permitted almost 100% of various polyphenolic dye decolourization and oxidation of adlerol and veratryl alcohol. Conclusions: The three laccases showed complementary biochemical features. BRFM 938 laccase had the highest thermo- and pH stability, catalytic efficiency towards 2,2′-azino-bis-[3-ethylthiazoline-6-sulfonate] and resistance to alcoholic solvents. BRFM 66 laccase had the highest rates of dye decolourization and oxidation of nonphenolic compounds. Significance and Impact of the Study: This study identified P. coccineus and P. sanguineus as outstanding producers of high redox potential laccases, easy to purify and scale-up for industrial production. Three new laccases proved to be suitable models for white biotechnology processes and for further molecular breeding to create a new generation of tailor-made enzymes. [ABSTRACT FROM AUTHOR]

Neuroanatomical data show that olfactory mucosa (OM) is a possible place for interactions between nutrition and smell. A combination of differential display mRNA analysis together with a macroarray screening was developed to identify transcripts that are differentially expressed in rat OM following food deprivation. Using this method, backed on a stringent statistical analysis, we identified molecules that fell into several Gene Ontology terms including cellular and physiological process, signal transduction, and binding. Among the 15 most differentially expressed molecules, only one was upregulated, but 14 were downregulated in the fasted state among which was, unexpectedly, odorant-binding protein 1F (OBP-1F). Because of its potential relevance to olfactory physiology, we focused our further analysis on OBP-1F using in situ hybridization, quantitative polymerase chain reaction, and western blot analysis. OBP-1F was highlighted in the lateral nasal glands, but its expression (mRNA and protein) did not change following food deprivation. Only the minor fraction of OBP-1F mRNA expressed by the OM itself was downregulated following 48 h fasting. Altogether, our results suggest that the fine transcriptional control of OBP-1F in the OM following food deprivation could be efficient only at the local level, close to its site of secretion to participate in the perireceptor events of the olfactory signal reception. [ABSTRACT FROM AUTHOR]

Y chromosome polymorphisms such as microsatellites or single nucleotide polymorphisms represent a paternal counterpart to mitochondrial DNA (mtDNA) for evolutionary and phylogeographic studies. The use of Y chromosome haplotyping in natural populations of species other than humans is still hindered by the lack of sequence information necessary for polymorphism screening. Here we used representational difference analysis (RDA) followed by a screen of a bacterial artificial chromosome (BAC) library for repetitive sequences to obtain polymorphic Y-chromosomal markers. The procedure was performed for the domestic horse (Equus caballus) and we report the first six Y-chromosomal microsatellite markers for this species. Three markers were also useful for haplotyping taxa of the zebra/ass lineage. Ychromosomal microsatellite markers show a single haplotype in the domestic horse, whereas notable variation has been observed in the other members of the genus Equus. [ABSTRACT FROM AUTHOR]