RESUMEN
Heavy metal pollution has become an environmental and health problem worldwide. With the aim of finding novel strategies for metal bioremediation, endophytic fungi from the heavy metal hyperaccumulator plant Vachellia farnesiana were isolated and characterized. The plants were growing in mine tailings, rich in Zn, Pb, and Cu. Morphological and phylogenetic analyses indicated that the fungal strains belonged to Neocosmospora and Aspergillus genera. The Neocosmospora isolate belongs to the Fusarium solani species complex (FSSC) that groups phytopathogen species. However, in this case the plants from which it was isolated did not show any signs of disease. Both fungal strains were able to remove significant amounts of heavy metals from liquid cultures, either in a mixture of the three metals or each metal in a single culture. In response to lead exposure, the Neocosmospora sp. strain secreted specific novel phenolic compounds other than anthraquinones or naphtoquinones, which have been described in similar situations. The Aspergillus sp. dropped the pH in the medium. High-performance liquid chromatography determinations indicated that this strain secreted mainly glutamic acid in response to lead, a novel mechanism, which has not been reported elsewhere. Malic and succinic acids were also produced in response to lead exposure. Possibly, glutamic and succinic acids (synthesized in the Krebs cycle) can be used to cope with metal toxicity due to the plant providing photosynthates to the fungus. These fungi showed the potential to be used for bioremediation or restoration of metal-polluted environments.
RESUMEN
BACKGROUND: In recent years, human keratitis caused by fungal plant pathogens has become more common. Biofilm is a structure that confers adaptations and virulence to fungi in keratitis. Neoscytalidium spp. are phytopathogenic and recently have been recognised as a human pathogen, using biofilm formation as a virulence factor. OBJECTIVES: The aim of this study was isolation, identification (at the species level) and characterisation of a new fungal keratitis agent. PATIENTS/METHODS: The fungus was isolated from a 67-year-old male patient with a corneal ulcer. Biofilm formation and structure were evaluated by colorimetric methods and microscopy. To identify the fungus, morphological characteristics were examined and a phylogenetic analysis was performed. RESULTS AND CONCLUSIONS: We report the identification of a fungus, a member of the genus Neoscytalidium which is associated with human keratitis. Phylogenetic analysis and morphological observations on conidiogenous cells, which occur only in arthric chains in aerial mycelium and the coelomycetous synasexual morph is absent, identified a new species, Neoscytalidium oculus sp. nov. The fungus formed biofilm at a concentration of 1 × 106 conidia/mL, during 96 hours of incubation at 37°C, and also manifested haemolysis and melanin production. This is the first report in Latin America of a new species of Neoscytalidium from a clinical isolate has been identified.
Asunto(s)
Ascomicetos/clasificación , Ascomicetos/aislamiento & purificación , Biopelículas/crecimiento & desarrollo , Úlcera de la Córnea/microbiología , Micosis/microbiología , Anciano , Ascomicetos/genética , Ascomicetos/crecimiento & desarrollo , Úlcera de la Córnea/patología , Humanos , Masculino , Técnicas Microbiológicas , Microscopía , Micosis/patología , FilogeniaRESUMEN
Two interesting fungi belonging to the genus Cordana have been isolated recently in Spain from plant debris. Both are proposed here as new species, described and illustrated. Cordana mercadiana sp. nov. produces 0-1-septate conidia, with a prominent basal scar. Cordana verruculosa sp. nov. differs from the other species of the genus by its unique combination of aseptate, verruculose and small conidia. Both species are compared morphologically with other species of Cordana and their identities supported by the analysis of rDNA sequences. LSU sequence analysis revealed the congeneric relationship of Cordana and Pseudobotrytis; the members of both genera are in a well supported monophyletic lineage that appears to be related to the Coniochaetales but remains incertae sedis within the Sordariomycetes. To establish nomenclatural stability of the genus Cordana, an isolate of C. pauciseptata is designed here as epitype and the two species of Pseudobotrytis are transferred to Cordana. A dichotomous key is provided to identify the currently accepted species of Cordana.
Asunto(s)
Ascomicetos/clasificación , Ascomicetos/genética , Ascomicetos/aislamiento & purificación , Ascomicetos/ultraestructura , Secuencia de Bases , ADN de Hongos/química , ADN de Hongos/genética , ADN Espaciador Ribosómico/química , ADN Espaciador Ribosómico/genética , Datos de Secuencia Molecular , Técnicas de Tipificación Micológica , Filogenia , Plantas/microbiología , Análisis de Secuencia de ADN , España , Especificidad de la Especie , Esporas FúngicasRESUMEN
Several new species belonging to the anamorph genera Bactrodesmiastrum and Bactrodesmium, collected from plant debris in Spain, are described and illustrated. Bactrodesmiastrum pyriforme, sp. nov. is characterized by large, pyriform conidia. Bactrodesmiastrum obovatum comb. nov. is proposed to accommodate janetia obovata, and the Spanish specimen of B. obscurum. the type species of the genus, represents the second known collection of the species worldwide. Analyses of rDNA sequences confirm the distinction between B. obovatum and B. pyriforme, and reveal their relationships with the Savoryellales (Sordariomycetes). Bactrodesmium diver-sum sp. nov. is distinguished from the other species of the genus by its large, pale brown conidia with a conspicuous pore at each septum.
Asunto(s)
Ascomicetos/aislamiento & purificación , Madera/microbiología , Ascomicetos/clasificación , Ascomicetos/genética , ADN de Hongos/genética , ADN Ribosómico/genética , Datos de Secuencia Molecular , Filogenia , ARN Ribosómico 16S/genética , EspañaRESUMEN
Se obtienen varias muestras durante un brote epizzótico en palomas Columba livia domestica ocurrido a finales de 1970 en la colina universitaria de la Ciudad de La Habana, de las cuales se lograron 2 aislamientos virales. En el presente trabajo se describe la metodología seguida para la identificación de uno de estos aislamientos, que fue identificado como una cepa del virus de la encefalomielitis equina del este (EEE). Se discuten varios aspectos ecológicos relacionados con el hecho de que otro aislamiento obtenido de las muestras del mismo brote fue identificado anteriormente como encefalitis equina del oeste (EEO)
Asunto(s)
Animales , Columbidae/microbiología , Virus de la Encefalitis Equina del Este/aislamiento & purificación , Técnica del Anticuerpo Fluorescente/métodosRESUMEN
Se obtienen varias muestras durante un brote epizoótico en palomas Columba livia domestica ocurrido a finales de 1970 en la colina universitaria de la Ciudad de La Habana de las cuales se lograron 2 aislamientos virales. En el presente trabajo se describe la metodología seguido para la identificación de uno de estos aislamientos, que fue identificado como una cepa del virus de la encefalomelitis equina del este (EEE). Se discuten varios aspectos ecológicos relacionados con el hecho de que otro aislamiento obtenido de las muestras del mismo brote fue identificado anteriormente como encefalitis equina del oeste (EEO)(AU)