Distinct roles of Candida albicans-specific genes in host-pathogen interactions

Peer reviewedPreprin

Distinct roles of Candida albicans-specific genes in host-pathogen interactions

Peer reviewedPreprin

Analysis and diagnosis of the state of conservation and restoration of paper-based artifacts: a non-invasive approach

We report a non-invasive and multi-analytical physico-chemical method for the characterization of paper artworks, able to identify sizing, inks, and glues and to quantify oxidative degradation by-products. The proposed methodology is mostly carried out in situ by using easy-to-use and cheap portable instrumentation for the acquisition of multispectral images, punctual ultraviolet-visible-near infrared fiber-optics reflectance spectroscopy (FORS) and punctual fiber optics fluorescence spectroscopy. Further analytical information is provided by non-invasive in-situ sampling of paper surface by using soft latex sponges, making possible laboratory chromatographic and infrared spectroscopic analyses on the aqueous sponge extracts. The proposed diagnostics method was applied to two 17th century letters written by St Francis of Sales (1567–1622), collected at the Chigi Palace in the town of Ariccia (Italy). Results show an intense oxidative degradation of the letters, also localized in water spots, and the presence of carboxylic acids by-products. Analysis of FORS spectra provided the concentration of chromophores in the paper substrate. The diagnostic method allowed the identification of gelatin sizing, the presence of starch glue in specific areas of the letters and the type of ink used in the text. Our diagnostic approach aims to offer to conservator-restorer a characterization of a paper artwork, that can be applied to other, for a correct planning of conservation interventions

Global transcriptome sequencing identifies chlamydospore specific markers in Candida albicans and Candida dubliniensis.

Candida albicans and Candida dubliniensis are pathogenic fungi that are highly related but differ in virulence and in some phenotypic traits. During in vitro growth on certain nutrient-poor media, C. albicans and C. dubliniensis are the only yeast species which are able to produce chlamydospores, large thick-walled cells of unknown function. Interestingly, only C. dubliniensis forms pseudohyphae with abundant chlamydospores when grown on Staib medium, while C. albicans grows exclusively as a budding yeast. In order to further our understanding of chlamydospore development and assembly, we compared the global transcriptional profile of both species during growth in liquid Staib medium by RNA sequencing. We also included a C. albicans mutant in our study which lacks the morphogenetic transcriptional repressor Nrg1. This strain, which is characterized by its constitutive pseudohyphal growth, specifically produces masses of chlamydospores in Staib medium, similar to C. dubliniensis. This comparative approach identified a set of putatively chlamydospore-related genes. Two of the homologous C. albicans and C. dubliniensis genes (CSP1 and CSP2) which were most strongly upregulated during chlamydospore development were analysed in more detail. By use of the green fluorescent protein as a reporter, the encoded putative cell wall related proteins were found to exclusively localize to C. albicans and C. dubliniensis chlamydospores. Our findings uncover the first chlamydospore specific markers in Candida species and provide novel insights in the complex morphogenetic development of these important fungal pathogens