Selective degradation of peroxisomes (macropexophagy) in Hansenula polymorpha involves the sequestration of individual organelles to be degraded by membranes prior to the fusion of this compartment with the vacuole and subsequent degradation of the whole organelle by vacuolar hydrolases. Here we show that Pex3p, a peroxisomal membrane protein essential for peroxisome biogenesis, escapes this au...

We report on the rerouting of peroxisomal alcohol oxidase (AO) to the secretory pathway of Hansenula polymorpha. Using the leader sequence of the Saccharomyces cerevisiae mating factor alpha (MFalpha) as sorting signal, AO was correctly sorted to the endoplasmic reticulum (ER), which strongly proliferated in these cells. The MFalpha presequence, but not the prosequence, was cleaved from the pro...

Evidence is accumulating that damaged components of eukaryotic cells are removed by autophagic degradation (e.g., mitophagy). Here we show that peroxisomes that are damaged by the abrupt removal of the membrane protein Pex3 are massively and rapidly degraded even when the cells are placed at peroxisome-inducing conditions and hence need the organelles for growth. Pex3 degradation was induced by...

This paper deals with the design of an intelligent control structure for a bioprocess of Hansenula polymorpha yeast cultivation. The objective of the process control is to produce biomass in a desired physiological state. The work demonstrates that the designed Hybrid Control Techniques (HCT) are able to recognize specific evolution bioprocess trajectories using neural networks trained specific...

Urate oxidase is an important enzyme with therapeutic and diagnostic applications. Rasburicase is a recombinant urate oxidase enzyme approved by FDA to use in the treatment of hyperuricemia conditions. Various hosts such as Saccharomyces cerevisiae, Hansenula polymorpha and Escherichia coli have been used to express the enzyme. Today, Pichia pastoris is considered as an important host for heter...

Recent advances in the availability and applicability of genetic tools for non-conventional yeasts have raised high hopes regarding the industrial applications of such yeasts; however, quantitative physiological data on these yeasts, including intracellular flux distributions, are scarce and have rarely aided in the development of novel yeast applications. The compartmentation of eukaryotic cel...

The Hansenula polymorpha genes encoding the putative functional homologs of the enzymes involved in the seventh and eighth step in purine biosynthesis, HpPUR7 and HpPUR8, were cloned and sequenced. An overexpression vector designated pHIPA4 was constructed, which contains the HpPUR7 gene as selectable marker and allows expression of genes of interest via the strong, inducible alcohol oxidase pr...

We have cloned and characterized the Hansenula polymorpha PER9 gene by functional complementation of the per9-1 mutant of H. polymorpha, which is defective in peroxisome biogenesis. The predicted product, Per9p, is a polypeptide of 52 kDa with sequence similarity to Pas3p, a protein involved in peroxisome biogenesis in Saccharomyces cerevisiae. In a per9 disruption strain (Deltaper9), peroxisom...

A mutant of the methylotrophic yeast Hansenula polymorpha with constitutive alcohol oxidase (AOX) and peroxisome biosynthesis was obtained after UV treatment followed by cell plating on a medium containing methanol and 2-deoxy-D-glucose (DOG). DOG-resistant colonies of mutants were insensitive to catabolic repression by glucose and methanol. A selection procedure is described that allows the is...

Hansenula polymorpha ass3 mutants are characterized by the accumulation of inactive alcohol oxidase (AO) monomers in the cytosol, whereas other peroxisomal matrix proteins are normally activated and sorted to peroxisomes. These mutants also have a glutamate or aspartate requirement on minimal media. Cloning of the corresponding gene resulted in the isolation of the H. polymorpha PYC gene that e...