Identification of fungi of the genus Aspergillus section nigri using polyphasic taxonomy

Abstract

In spite of the taxonomy of the Aspergillus species of the Nigri Section being regarded as troublesome, a number of methods have been proposed to aid in the classification of this Section. This work aimed to distinguish Aspergillus species of the Nigri Section from foods, grains and caves on the basis in Polyphasic Taxonomy by utilizing morphologic and physiologic characters, and sequencing of ß-tubulin and calmodulin genes. The morphologic identification proved useful for some species, such as A. carbonarius and Aspergillus sp UFLA DCA 01, despite not having been totally effective in elucidating species related to A. niger. The isolation of the species of the Nigri Section on Creatine Sucrose Agar (CREA) enabled to distinguish the Aspergillus sp species, which was characterized by the lack of sporulation and by the production of sclerotia. Scanning Electron microscopy (SEM) allowed distinguishing the species into two distinct groups. The production of Ochratoxin A (OTA) was only found in the A. carbonarius and A. niger species. The sequencing of β-tubulin gene was efficient in differing most of the Aspergillus species from the Nigri Section with the exception of Aspergillus UFLA DCA 01, which could not be distinguished from A. costaricaensis. This species is morphologically similar to A. costaricaencis for its low sporulation capacity and high sclerotia production, but it differs morphologically from A. costaricaensis for its conidial ornamentation and size of vesicles. Equally, based on partial calmodulin gene sequence data Aspergillus UFLA DCA 01 differs from A. costaricaensis

Chemical composition and antifungal activity of essential oil from Eucalyptus smithii against dermatophytes

“…The samples were then washed three times (each wash for 10 min) with the same buffer and were post-fi xed with 1% (w/v) osmium tetroxide for 1h. The postfi xed samples were given three brief washes with distilled water and were dehydrated using increasing concentrations of acetone (25-100% v/v) at every 10-min interval (29) . The samples were then assembled in aluminum stubs with double-faced carbon tapes, placed on an aluminum foil sputter coated with gold (2mm) (FL-9496, Balzers, Fürstentum Liechtenstein), and observed by SEM (JSM 6390LV; Jeol, Tokyo, Japan) under 25kw power and a work distance of 17mm.…”

Aspergillus homomorphus, a first global record from millet grains

“…aculeatinus, A. aculeatus, A. assiutensis, A. brunneoviolaceus, A. indologenus, A. japonicus and A. uvarum ranging from 94.2-94.7%. In similar studies, A. homomorphus and uniseriate species were located in either one subclade or two neighboring clades (Samson et al 2004, Silva et al 2011.…”

“…Afterwards, the samples were dried in a desiccator containing silica. The specimens were clustered on a film of aluminum foil, then coated with gold in a sputter and observed in a scanning electron microscope, SEM (JEOL, JSM-5400 LV unit, Assiut University, Assiut, Egypt) (Silva et al 2011).…”

Optimization of headspace solid phase microextraction for the analysis of microbial volatile organic compounds emitted by fungi: Application to historical objects

“…It was found on the organic debris present in the cracks of archeological ceramics. This species was identified based on key book and literature [57][58][59] after observation of growth, morphology and samples prepared on slides, under a microscope. All four species were also found in the indoor air of the storage rooms of the National Museum in Krakow [3].…”