Molecular analysis and pathogenicity of the Cladophialophora carrionii complex, with the description of a novel species.

Cladophialophora carrionii is one of the four major etiologic agents of human chromoblastomycosis in semi-arid climates. This species was studied using sequence data of the internal transcribed spacer region of rDNA, the partial beta-tubulin gene and an intron in the translation elongation factor 1-alpha gene, in addition to morphology. With all genes a clear bipartition was observed, which corresponded with minute differences in conidiophore morphology. A new species, C. yegresii, was introduced, which appeared to be, in contrast to C. carrionii, associated with living cactus plants. All strains from humans, and a few isolates from dead cactus debris, belonged to C. carrionii, for which a lectotype was designated. Artificial inoculation of cactus plants grown from seeds in the greenhouse showed that both fungi are able to persist in cactus tissue. When reaching the spines they produce cells that morphologically resemble the muriform cells known as the "invasive form" in chromoblastomycosis. The tested clinical strain of C. carrionii proved to be more virulent in cactus than the environmental strain of C. yegresii that originated from the same species of cactus, Stenocereus griseus. The muriform cell expressed in cactus spines can be regarded as the extremotolerant survival phase, and is likely to play an essential role in the natural life cycle of these organisms.

Human leukocyte antigen class I and MICA haplotypes in a multicase family with Cladophialophora carrionii chromoblastomycosis.

Previous studies carried out in an endemic semiarid region northwest of Venezuela at Falcon State have shown a prevalence of 15.4/1000 of chromoblastomycosis following traumatisms with xenophile vegetation infected with Cladophialophora carrionii. We performed high-resolution DNA typing of human leukocyte antigen (HLA)-A, -B and -C and major histocompatibility complex class I chain related gene A (MICA) alleles and segregation analysis in 49 members of one extended family with 12 affected individuals, who have lived for approximately 70 years in this endemic zone. None of the alleles, haplotypes or genotypes is shared by all the patients. No deviation from the expected HLA haplotype distribution or association of chromoblastomycosis with HLA-A, -B and -C haplotypes was observed. Further, a haplotype-sharing transmission/disequilibria testing of 11 nuclear families did not give enough evidence to claim linkage (P = 0.398), suggesting that genes located in the short arm of chromosome 6 may not be relevant in the immune response toward infection with C. carrionii in this Venezuelan endemic zone. Deleted MICA alleles on HLA-B*4802 haplotypes were present among several members of the extended family, but only two of them were affected.

Saccharomyces cerevisiae en la fabricación del licor cocuy / Sacchromyces cerevisiae in the manufacturing of cocoy liquor

El licor "cocuy" es una bebida artesanal, producida por las comunidades rurales en el Occidente de Venezuela mediante un proceso de fermentación y destilación del mosto extraído del Agave cocui. Este estudio fue enmarcado en el "Programa Agave" con el propósito de contribuir a rescatar esta actividad productiva tradicional. En vista de la falta de información en relación al proceso autóctono se hicieron estudios de las levaduras fermentadoras, la optimización de la producción de etanol y la utilización del residuo de la destilización (vinaza) como medio de cultivo. Los aislados con mayor capacidad fermentativa fueron seleccionados e identificados mediante parámetros morfológicos y metabólicos. Se compararon los niveles de consumo de azúcar de las levaduras con mayor capacidad fermentativa. Se estudió el efecto de la adición del azúcar blanca comercial y/o del fosfato de amonio y en la producción del alcohol en el proceso artesanal. Las concentraciones de azúcares en el mosto se evaluaron por refractometría, y el contenido de alcohol de licor por hidrometría. La utilización de la vinaza para la producción de biomasa como un componente del medio de cultivo fue comparada con un medio sintético mediante medidas del peso seco de la biomasa. Se confirma el papel de sccharomyces ceravisiae en el proceso fermentativo espontáneo. Los resultados in situ evidenciaron un efecto favorable de la elevación del contenido de azúcar (11 a 18 °Brix) y de la adición de fosfato de amonio dibásico (0,2 g/l). En estas condiciones, el tiempo de fermentación del mosto se acortó y la producción de licor aumentó hasta un 92 por ciento. Se demostró la posibilidad de utilizar la vinaza como un componente para un medio de cultivo de esta levadura, para iniciar la fermentación y para la producción de biomasa como fuente de nutrientes de alto valor nutritivo para aves de corral o caprinos. Se recomienda apoyar los esfuerzos para desarrollar de esta importante fuente para los campesinos que habitan las zonas semiáridas de los estados Falcón y Lara

Black fungi: clinical and pathogenic approaches.

Data are presented on the clinically relevant black yeasts and their relatives, i.e., members of the Ascomycete order Chaetothyriales. In order to understand the pathology of these fungi it is essential to know their natural ecological niche. From a relatively low degree of molecular variability of the black yeast Exophiala dermatitidis, potential agent of brain infections in patients from East Asia, it is concluded that this species is an emerging pathogen, currently going through a process of active speciation. It is found to be an oligotrophic fungus in hot, moist environments, such as steambaths. Cladophialophora-, Fonsecaea- and Ramichloridium-like strains, known in humans as agents of chromoblastomycosis, are frequently found on rotten plant material, but the fungal molecular diversity in the environment is much higher than that on the human patient, so that it is difficult to trace the etiological agents of the disease with precision. This approach has been successful with Cladophialophora carrionii, of which cells resembling muriform cells, the tissue form of chromoblastomycosis, were found to occur in drying spines of cacti. Phagocytosis assays provide a method to distinguish between pathogens and non-pathogens, as the killing rates of strict saprobes proved to be consistently higher than of those species frequently known as agents of disease. The therapeutic possibilities for patients with chromoblastomycosis are reviewed.

Cromomisosis por Cladophialophora carrionii: estudio del componente genético en la zona endémica en Venezuela / Chromomycosis for Cladophialophora carrionii: genetic component study in Venezuela endemic zone

Con el fin de conocer los factores que puedan explicar la alta prevalencia de cromomicosis en la zona endémica del estado Falcón, se encuestaron los pobladores de 3 caseríos situados en la zona semiárida. Se elaboraron las genealogías, se aplicó el Indice de Falconer y se ubicó el foco geográfico. Se realizaron estudios micológicos y aislamiento del agente del ambiente peridomiciliari mediante microcultivos. Se diagnosticaron 21 (1,54 por ciento) casos por C. carrionii en 1.356 personas: 20 (95 por ciento) pertenecían a un mismo grupo familiar, con una relación de uniones consanguíneas de 1/4; 7 (54 por ciento) de los casos producto directo de éstas. Se demostró la presencia del agente en una cactácea, Opuntia caribaea (guazábara). Se observó un patrón de herencia correspondiente a un gen autosómico recesivo. Se estimó una heredabilidad del 47 por ciento (5,6 por ciento de hermanos afectados). Nuestros resultados demuestran una alta participación del componente genético en esta micosis profunda, factor determinante para explicar la endemia en estas poblaciones rurales, sedentarias y aisladas con tendencia a las uniones consanguíneas. Se proponen estrategias racionales para el control de la endemia

Virulence and pathogenicity of human and environmental isolates of Cladosporium carrionii in new born ddY mice.

Three strains of Cladosporium carrionii, two human isolates and one from a xerophilous plant, were used to study the effect of culture conditions in 106 newborn ddY mice. Growth in a complex medium (YPG) and a basal synthetic medium (BSM) was compared. Filamentous forms developed during static incubation while conidia were readily formed with shaking. Mice inoculated intraperitoneally were sacrificed and autopsied after 4 weeks. Mortality was related only to sporulated exponential phase growing cells. Invasiveness ability was preserved in all experimental conditions. BSM medium that inhibited exopigment formation appeared more suitable than YPG to obtain intact cells for further studies. Biochemical and physiological alteration associated with shape changes during differentiation of vegetative cells into spores could play an important role in virulence of C. carrionii.