Automated electron tomography of the septal pore cap in Rhizoctonia solani

Dolipore septa and septal pore caps (SPCs) in filamentous basidiomycetes may play an important role in maintaining the integrity of hypal cells. We have investigated the ultrastructure of the dolipore septum and the SPC in Rhizoctonia solani hyphal cells after high-pressure freezing, freeze substitution, and Spurr embedding. We visualized the...

Glucoamylasegreen fluorescent protein fusions to monitor protein secretion in Aspergillus niger

A glucoamylase::green fluorescent protein fusion (GLA::sGFP) was constructed which allows the green fluorescent protein to be used as an in vivo reporter of protein secretion in Aspergillus niger. Two secretory fusions were designed for secretion of GLA::sGFP which employed slightly different lengths of the glucoamylase protein (GLA499 and...

Characterization of a foldase, protein disulfide isomerase A, in the protein secretory pathway of Aspergillus niger

Protein disulfide isomerase (PDI) is important in assisting the folding and maturation of secretory proteins in eukaryotes. A gene, pdiA, encoding PDIA was previously isolated from Aspergillus niger, and we report its functional characterization here. Functional analysis of PDIA showed that it catalyzes the refolding of denatured and reduced...

Localization of synthesis of β1,6-glucan in Saccharomyces cerevisiae

β1,6-Glucan is a key component of the yeast cell wall, interconnecting cell wall proteins, β1,3-glucan, and chitin. It has been postulated that the synthesis of β1,6-glucan begins in the endoplasmic reticulum with the formation of protein-bound primer structures and that these primer structures are extended in the Golgi complex by two putative...

Study of the glucoamylase promoter in Aspergillus niger using green fluorescent protein

An Aspergillus niger strain expressing a red-shifted green fluorescent protein (GFP) in the cytoplasm under the control of the glucoamylase promoter (PglaA) was characterized with respect to its physiology and morphology. Although xylose acted as a repressor carbon source during batch cultivations, PglaA-driven GFP expression by the glucoamylase...

Biochemical and structural characterization of the glucan and fructan exopolysaccharides synthesized by the Lactobacillus reuteri wild-type strain and by mutant strains

Lactobacillus reuteri LB 121 cells growing on sucrose synthesize large amounts of a glucan (D-glucose) and a fructan (D-fructose) with molecular masses of 3,500 and 150 kDa, respectively. Methylation studies and 13C or 1H nuclear magnetic resonance analysis showed that the glucan has a unique structure consisting of terminal, 4-substituted, 6...

An improved colony-PCR method for filamentous fungi for amplification of pcr-fragments of several kilobases

A method was developed to perform PCR directly on mycelial pellets or colonies treated with NOVOzym 234. The method allows rapid screening of large numbers of transformants of both sporulating and non-sporulating fungi for the presence of (co)transforming plasmid copies or for specific genetic modifications such as gene disruption and site...

Optimization and stability of glucoamylase production by recombinant strains of Aspergillus niger in chemostat culture

When grown on a medium containing 5 g maltodextrin L-1, Aspergillus niger transformant N402[pAB6-10]B1, which has an additional 20 copies of the glucoamylase (glaA) gene, produced 320 ± 8 mg (mean ± S.E.) glucoamylase (GAM) L-1 in batch culture and 373 ± 9 mg GAM L-1 in maltodextrin- limited chemostat culture at a dilution rate of 0.13 h-1....

Analysis of the role of the gene bipA, encoding the major endoplasmic reticulum chaperone protein in the secretion of homologous and heterologous proteins in black Aspergilli

The function of the endoplasmic-reticulum-localized chaperone binding protein (BiP) in relation to protein secretion in filamentous fungi was studied. It was shown that the overproduction of several homologous and heterologous recombinant proteins by Aspergillus strains induces the expression of bipA, the BiP-encoding gene from Aspergillus niger...

Glucoamylase gene fusions alleviate limitations for protein production in Aspergillus awamori at the transcriptional ans (post)translational levels

In this study we have analyzed the effects of a glucoamylase gene fusion on the mRNA levels and protein levels for the human interleukin-6 gene (hil6) and the guar α-galactosidase gene (aglA). Previously it was shown that production of nonfused α-galactosidase and hIL-6 in Aspergillus awamori was limited at transcriptional and (post...

An expression system based on the promoter region of the Aspergillus awamori 1,4-bèta-endoxylanase A gene

A new, highly inducible fungal promoter derived from the Aspergillus awamori 1,4-β-endoxylanase A (exlA) gene is described. Induction analysis, carried out with the wild-type strain in shake flasks, showed that exlA expression is regulated at the transcriptional level. Using a β-glucuronidase (uidA) reporter strategy, D-xylose was shown to be an...

Safety evaluation of β-glucanase derived from Trichoderma reesei: Summary of toxicological data

Barlican, a β-glucanase enzyme obtained from Trichoderma reesei, was produced by a fermentation process and subjected to a series of toxicological tests to document its safety for use as a feed additive. The enzyme product was examined for general oral toxicity, inhalation toxicity, irritation to eye and skin, skin sensitization and mutagenic...

The effect of multiple copies of the upstream region of the Aspergillus niger glucoamylase-encoding gene on expression

The regulation of transcription of the glucoamylase-encoding gene (glaA) of Aspergillus niger was studied. To facilitate this study a reporter strain containing a fusion of the glaA promoter (P(glaA)) of A. niger to the β- glucuronidase-encoding gene (uidA) of Escherichia coli was constructed. To analyze whether regulatory proteins are involved...

Glucoamylase overexpression in Aspergillus niger: Molecular genetic analysis of strains containing multiple copies of the glaA gene

A strategy, based on the usage of the amdS selection marker and a cosmid vector containing four copies of the glucoamylase gene (glaA), was developed to obtain glucoamylase (GLA)-overproducing A. niger strains. With this strategy, fungal strains carrying up to 200 copies of the glaA gene could be isolated at a relatively high frequency. In each...

Production of extracellular proteins by the filamentous fungus Aspergillus

Intracellular and extracellular production of proteins in Aspergillus under the control of expression signals of the highly expressed Aspergillus nidulans gpdA gene

The expression in Aspergillus is described of genes, coding for intracellular and extracellular proteins controlled by the promoter region of the constitutively and efficiently expressed glyceraldehyde-3-phosphate dehydrogenase gene (gpdA) of Aspergillus nidulans. Both the homologous gpdA and the heterologous Escherichia coli β-galactosidase ...