Different Hydrophobins of Fusarium graminearum Are Involved in Hyphal Growth, Attachment, Water-Air Interface Penetration and Plant Infection

Hydrophobins (HPs) are small secreted fungal proteins possibly involved in several processes such as formation of fungal aerial structures, attachment to hydrophobic surfaces, interaction with the environment and protection against the host defense system. The genome of the necrotrophic plant pathogen Fusarium graminearum contains five genes encoding for HPs (FgHyd1-5). Single and triple FgHyd mutants were produced and characterized. A reduced growth was observed when the ΔFghyd2 and the three triple mutants including the deletion of FgHyd2 were grown in complete or minimal medium. Surprisingly, the growth of these mutants was similar to wild-type when grown under ionic, osmotic or oxidative stress conditions. All the mutant strains confirmed the ability to develop conidia and perithecia, suggesting that the FgHyds are not involved in normal development of asexual and sexual structures. A reduction in the ability of hyphae to penetrate through the water-air interface was observed for the single mutants ΔFghyd2 and ΔFghyd3 as well as for the triple mutants including the deletion of FgHyd2 and FgHyd3. Besides, ΔFghyd3 and the triple mutant ΔFghyd234 were also affected in the attachment to hydrophobic surface. Indeed, wheat infection experiments showed a reduction of symptomatic spikelets for ΔFghyd2 and ΔFghyd3 and the triple mutants only when spray inoculation was performed. This result could be ascribed to the affected ability of mutants deleted of FgHyd2 and FgHyd3 to penetrate through the water-air interface and to attach to hydrophobic surfaces such as the spike tissue. This hypothesis is strengthened by a histological analysis, performed by fluorescence microscopy, showing no defects in the morphology of infection structures produced by mutant strains. Interestingly, triple hydrophobin mutants were significantly more inhibited than wild-type by the treatment with a systemic triazole fungicide, while no defects at the cell wall level were observed

Molecular Mechanisms of Resistance to Antifungals in <em>Candida albicans</em>

Invasive Candidiasis (IC) presents a global mortality rate greater than 40%, occupying the fourth place worldwide as the most frequent opportunistic nosocomial disease. Although the genus Candida consists of around 200 species, only 20 are reported as etiological agents of IC, being Candida albicans the most frequent causal agent. Even when there is a broad range of antifungals drugs for Candida infections, azoles, polyenes, and echinocandins are considered among the most effective treatment. However, there is some incidence for antifungal resistance among some Candida strains, limiting treatment options. Several molecular mechanisms with antifungal agents have been reported for C. albicans where insertions, deletions, and point mutations in genes codifying target proteins are frequently related to the antifungal drug resistance. Furthermore, gene overexpression is also frequently associated to antifungal resistance as well as an increase in the activity of proteins that reduce oxidative damage. This chapter summarizes the main molecular mechanisms to C. albicans antifungal drug resistance, besides offering an overview of new antifungal agents and new antifungal targets to combat fungal infections

Fungal Alcohol Dehydrogenases: Physiological Function, Molecular Properties, Regulation of Their Production, and Biotechnological Potential

Fungal alcohol dehydrogenases (ADHs) participate in growth under aerobic or anaerobic conditions, morphogenetic processes, and pathogenesis of diverse fungal genera. These processes are associated with metabolic operation routes related to alcohol, aldehyde, and acid production. The number of ADH enzymes, their metabolic roles, and their functions vary within fungal species. The most studied ADHs are associated with ethanol metabolism, either as fermentative enzymes involved in the production of this alcohol or as oxidative enzymes necessary for the use of ethanol as a carbon source; other enzymes participate in survival under microaerobic conditions. The fast generation of data using genome sequencing provides an excellent opportunity to determine a correlation between the number of ADHs and fungal lifestyle. Therefore, this review aims to summarize the latest knowledge about the importance of ADH enzymes in the physiology and metabolism of fungal cells, as well as their structure, regulation, evolutionary relationships, and biotechnological potential

Infodiversidad. La biblioteca como centro multicultural

El Coloquio Internacional de Bibliotecarios que en este año se realiza bajo el tema Infodiversidad: la biblioteca como centro multicultural tiene el propósito de servir como un espacio de diálogo y reflexión sobre uno de los nuevos escenarios que se han creado con el advenimiento de la sociedad de la información, la infodiversidad. Han transcurrido ya más de veinte años desde la primera celebración en 1987 del Coloquio Internacional de Bibliotecarios, y el interés y la ilusión no han fenecido; por el contrario se han fortalecido, sin duda por el nivel de compromiso al que han llegado las instituciones y profesionales de la información implicados en la realidad compleja y diversa del mundo de las bibliotecas y la documentación