Diagnostic tools to identify black aspergilli

Abstract

The present taxonomy of the black aspergilli reveals that there are 19 accepted taxa. However the identification of species of Aspergillus section Nigri is often problematic in spite of the existence of numerous methods proposed. An overview is provided of phenotypic and molecular methods to identify the accepted species of the black aspergilli. Colony morphology, conidial size and ornamentation of the ex type cultures is presented in a pictorial overview. The temperature range of all species is given and their growth characteristics on creatine agar and boscalid agar, a medium which was developed as a selective medium for the isolation of A. carbonarius are also shown. The extrolites produced by each species are listed while the response of the Ehrlich reaction is described. The literature on the various molecular methods to be used for species identification is reviewed and a critical evaluation of the usefulness of various techniques and genomic loci for species identification of black aspergilli is presented.

Bioprospecting Aspergillus section Nigri in Atlantic Forest soil and plant litter

“…After an inoculation period of seven days, their macroscopic (color of surface and back of the colony, colony diameter, presence or absence and color of sclerotia) and microscopic (vesicle diameter and form, phialide length and width, color, size, form and texture of the conidia, and color of the hyphae) characteristics were analyzed. Inoculations were also carried out in Petri dishes containing MEA medium for 10 days to verify growth at temperatures of 15, 33, 36, and 40ºC (KLICH, 2002;SAMSON et al, 2004;SAMSON et al, 2007;VARGA et al, 2011;MEIJER et al, 2011).…”

Black Aspergillus species isolated from clinical and environmental samples in Iran

“…In general, black Aspergillus species can be distinguished via a polyphasic approach, using morphology, physiology and molecular data (Samson et al, 2007); nevertheless, most of the species belonging to Aspergillus section Nigri are usually considered as A. niger based on only morphological characters (Martínez-Culebras & Ramon, 2007 Recently, clinical isolates thought to belong to A. niger have been reclassified by genetic tools as A. tubingensis, A. awamori, A. uvarum and A. brasiliensis (Perrone et al, 2008;Manikandan et al, 2010;Hendrickx et al, 2012;Szigeti et al, 2012). Accordingly, A. niger is not the only black Aspergillus species involved in infections, Indeed A. tubingensis and other black Aspergillus species are also able to cause infections.…”

Occurrence of black Aspergilli in indoor environments of six countries

“…Many species cause food spoilage, but are also used in the fermentation industry to produce various enzymes and organic acids (4). Some species also act as plant pathogens, including A. carbonarius and A. niger in grapes, and A. welwitschiae in onions and the plant Welwitschia mirabilis (5,6).…”

“…Although data regarding fumonisin absorption following inhalation and/or dermal exposure are not available (10), ochratoxin A exposure via inhalation has been described in the literature to cause kidney disease in animals and humans (11), which is why precise identification at the species level is of immense importance. Recent data indicate that Aspergillus section Nigri comprises 25 species (4,(12)(13)(14), which can be divided into five main clades. The A. niger clade includes 10 biseriate species and was divided into three subclades based on ß-tubulin and calmodulin sequence data: the A. tubingensis, A. niger, and A. brasiliensis subclades (13).…”

“…Some species also act as plant pathogens, including A. carbonarius and A. niger in grapes, and A. welwitschiae in onions and the plant Welwitschia mirabilis (5,6). Moreover, several species can produce mycotoxins including ochratoxins and fumonisins that can be harmful for both humans and animals (4,(6)(7)(8)(9). Although data regarding fumonisin absorption following inhalation and/or dermal exposure are not available (10), ochratoxin A exposure via inhalation has been described in the literature to cause kidney disease in animals and humans (11), which is why precise identification at the species level is of immense importance.…”