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Metabolites of ochratoxins in rat urine and in a culture of Aspergillus ochraceus

Article Abstract:

The fungus Aspergillus ochraceus and rat form 4-R-hydroxyochratoxin A and ochratoxin-alpha (O-alpha) as the main products of metabolism of a substituted methylisocoumarin ochratoxin A (OA). Ochratoxin-beta, 4-R-hydroxyochratoxin B and 10-hydroxyochratoxin A ( 10-OH OA) are also produced. The formation of 10-OH OA in the fungus is conditional. The ochratoxins form macromolecules by the covalent linkage of O-alpha and OA but not OB. The linkage appears to be at the phenolic or carbonyl groups of ochratoxins rather than the carboxyl groups.

Observations, Metabolism, Coumarins, Rats as laboratory animals, Laboratory rats

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A sandwiched-culture technique for evaluation of heterologous protein production in a filamentous fungus

Article Abstract:

A sandwiched-culture method is proposed for analyzing heterologous protein secretion in filamentous fungus Aspergillus niger. Expression of the ABH1 hydrophobin of Agaricus bisporus in Aspergillus niger shows low production of heterologous protein, which may be attributed to extracellular proteolytic degradation of the protein. The sandwiched-culture technique is also reliable in detecting the production of engineered proteins which could not be detected in a culture medium of Schizophyllum commune.

Microbiology, Cultures (Biology), Proteins, Molds (Fungi)

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Functional analysis of the threonine- and serine-rich Gp-I domain of glucoamylase I from Aspergillus awamori var. kawachi

Article Abstract:

The C-terminal region of the threonine- and serine-rich Gp-1 domain of glucoamylase I (GAI) of Aspergillus awamori var. kawachi appears to be essential for secretion of GAI. Mutant genes containing deletions in the Gp-1 domain or a tandem repeat of the domain were expressed by a yeast-secretion vector in Saccharomyces cerevisiae. The Gp-1 repeat did not significantly enhance raw starch digestibility, although it did have higher carbohydrate content.

Serine, Threonine

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