Donald A. Mackenzie

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We transformed Aspergillus niger with the full length cDNA gene encoding hen egg-white lysozyme (HEWL) and its secretion signal sequence. Lysozyme levels up to 12 mg/l were secreted when expression was controlled by the A. awamori glucoamylase (GAM) promoter and 1 mg/l when controlled by the A. nidulans glyceraldehyde-3-phosphate dehydrogenase (GPD)(More)
Recent research has provided mechanistic insight into the important contributions of the gut microbiota to vertebrate biology, but questions remain about the evolutionary processes that have shaped this symbiosis. In the present study, we showed in experiments with gnotobiotic mice that the evolution of Lactobacillus reuteri with rodents resulted in the(More)
Mortierella alpina was transformed successfully to hygromycin B resistance by using a homologous histone H4 promoter to drive gene expression and a homologous ribosomal DNA region to promote chromosomal integration. This is the first description of transformation in this commercially important oleaginous organism. Two pairs of histone H3 and H4 genes were(More)
Genes encoding two distinct fatty acid delta9-desaturases were isolated from strains of the oleaginous fungus Mortierella alpina. Two genomic sequences, delta9-1 and delta9-2, each containing a single intron, were cloned from strain CBS 528.72 while one cDNA clone, LM9, was isolated from strain CBS 210.32. The delta9-1 gene encoded a protein of 445 aa which(More)
We describe a new endoplasmic reticulum (ER)-associated stress response in the filamentous fungus Aspergillus niger. The inhibition of protein folding within the ER leads to cellular responses known collectively as the unfolded protein response (UPR) and we show that the selective transcriptional downregulation of the gene encoding glucoamylase, a major(More)
15N-labeled hen lysozyme has been studied by 2D and 3D NMR in order to characterize its dynamic behavior. The resonances of all main-chain amide nitrogen atoms were assigned, as were resonances of nitrogen atoms in 28 side chains. Relaxation measurements for the main-chain and arginine and tryptophan side-chain 15N nuclei used standard methods, and those(More)
Physiological factors affecting hen eggwhite lysozyme and native glucoamylase production by Aspergillus niger have been examined in batch culture. Expression of the genes encoding both proteins was controlled by the glucoamylase promoter. In standard expression medium (ACMS/N/P), secreted lysozyme yields were found to be maximal at 20-25 degrees C (8-10 mg(More)
Despite the naturally high capacity for protein secretion by many species of filamentous fungi, secteted yields of many heterologous proteins have been comparatively low. The strategies for yield improvement have included the use of strong homologous promoters, increased gene copy number, gene fusions with a gene encoding a naturally well-secreted protein,(More)
Mucus-binding proteins (MUBs) have been revealed as one of the effector molecules involved in mechanisms of the adherence of lactobacilli to the host; mub, or mub-like, genes are found in all of the six genomes of Lactobacillus reuteri that are available. We recently reported the crystal structure of a Mub repeat from L. reuteri ATCC 53608 (also designated(More)
The cDNA gene encoding porcine pancreatic prophospholipase A2 (proPLA2) was cloned into an Aspergillus niger expression vector downstream of the glucoamylase (glaA) gene promoter region. When this construct was transformed into A. niger, no detectable PLA2 was produced. Evidence was obtained showing that the PLA2 gene was transcribed and that PLA2 is(More)