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Hansenula polymorpha.
A. A. Sibirny (1), V. M. Ubiyvovk (1), M. V. Gonchar (1), V. I. Titorenko (1), A. Y. Voronovsky (1), Y. G. Kapultsevich (2) and K. M. Bliznik (2). Reactions of direct formaldehyde oxidation to CO2 are non-essential for energy supply of yeast methylotrophic growth. Archives of Microbiology. Nov. 1990; 154(6): 566-575.
(1) Lviv Branch of A. V. Palladin Institute of Biochemistry,
Academy of Sciences of Ukrainian SSR, 290005 Lviv, USSR
(2) Institute of Genetics and Selection of Industrial
Microorganisms, 113545 Moscow, USSR
Abstract
Mutants of the methylotrophic yeast Hansenula polymorpha deficient in NAD-dependent formaldehyde or formate dehydrogenases have been isolated. They were more sensitive for exogenous methanol but retained the ability for methylotrophic growth. In the medium with methanol the growth yields of the mutant 35683 deficient in formaldehyde dehydrogenase and of the wild-type strain were identical (0.34 g cells/g methanol) under chemostat cultivation. These results indicate that enzymes of direct formaldehyde oxidation are not indispensable for methylotrophic growth. At the same time inhibition of tricarboxylic acid cycle has resulted in suppression of growth in the media with multicarbon nonfermentable substrates such as glycerol, succinate, ethanol and dihydroxyacetone as well as with methanol, but not with glucose. In the experiments with the wild-type strain H. polymorpha it has been shown that citrate and dihydroxyacetone inhibit the radioactivity incorporation from 14C-methanol into CO2. All obtained data indicate that for the dissimilation of methanol and the supplying of energy for methylotrophic growth, the functioning of tricarboxylic acid cycle reactions as oppossed to those of direct formaldehyde oxidation is essential.
Link Reference:
http://www.springerlink.com/content/r8v75x0845232173/United States Patent 4,871,669
Murray, et al. Production of natural flavor aldehydes from natural source primary alcohols C.sub.2 -C.sub.7. October 3, 1989.
Inventors: Murray; William D. (Ottawa, CA), Duff; Sheldon J. B. (Ottawa, CA), Lanthier; Patricia H. (Wilson's Corners, CA)
Assignee: Canadian Patents & Development Limited (Ottawa, CA)
Appl. No.: 07/211,879
Filed: June 27, 1988
Current U.S. Class: 435/147 ; 435/188; 435/921; 435/930; 435/938; 435/944
Current International Class: (C12P 7/24 20060101)
Field of Search: 435/930,147,188,921,938,944
Abstract
Methylotrophic yeasts of the genera Pichia, Torulopsis, Candida and Hansenula when grown on methanol, make use of an enzyme, alcohol oxidase, to catalyse the initial oxidation of methanol to formaldehyde. Non-growing whole cells of such methylotrophic yeasts were used in place of purified alcohol oxidase for the production of flavoring aldehydes from their respective alcohols. To reduce end product inhibition a number of amine buffers, which chelate the aldehydes, were studied and an increase in aldehyde production was demonstrated with selected buffers which maintain a weakly alkaline pH.
Link Reference:
USPTO 4,871, 669 Link Reference Richard G. Buckholz (1), (2) & Martin A. G. Gleeson (1), (3), (*). Yeast Systems for the Commercial Production of Heterologous Proteins. Nature Biotechnology, 1990. 9: 1067-1072
(1) Salk Institute Biotechnology/Industrial Associates, Inc.
(SIBIA) San Diego, CA 92037.
(2) Present address: Glaxo, Inc., 5 Moore Drive, Research
Triangle Park, NC 27709.
(3) Present address: Ligand Pharmaceuticals, Inc., 9393 Towne
Centre Drive, Suite 100, San Diego, CA 92121.
(*) Corresponding author.
Abstract:
Yeasts are attractive hosts for the production of heterologous proteins. Unlike prokaryotic systems, their eukaryotic subcellular organization enables them to carry out many of the post−translational folding, processing and modification events required to produce "authentic" and bioactive mammalian proteins. In addition, they retain the advantages of a unicellular microorganism, with respect to rapid growth and ease of genetic manipulation. The vast majority of yeast expression work has focused on the well−characterized baker's yeast Saccharomyces cerevisiae. However, with the development of DNA transformation technologies, a growing number of non−Saccharomyces yeasts are becoming available as hosts for recombinant polypeptide production. These include Hansenula polymorpha, Kluyveromyces lactis, Pichia pastoris, Schizosaccharomyces pombe, Schwanniomyces occidentalis and Yarrowia lipolytica. The performance of these alternative yeast expression systems is reviewed here relative to S. cerevisiae, and the advantages and limitations of these systems are discussed.
Link Reference:
Nature Biotechnology LinkGM Walker and JH Duffus. Magnesium ions and the control of the cell cycle in yeast. Journal of Cell Science, Vol 42, Issue 1 329-356.
Abstract
A study has been made of the role of magnesium ions in cell division cycle control in the fission yeast, Schizosaccharomyces pombe, and the budding yeast, Kluyveromyces fraglis. Synchronization of cell division in these organismms can be induced by restoring magnesium to magnesium-exhausted cultures. In S. pombe, a correlation exists between the time taken for cells to enter the first synchronous division and the period of magnesium exhaustion. During short-term incubation in magnesium-deficient media, S. pombe cells are observed to continue growth in length, but they fail to make a cell plate and divide; long-term magnesium deficiency results in the production of aberrant cell forms, and a reduction in viability. Analysis of total cell magnesium in cultures of both S. pombe and K. fragilis, synchronized by various induction and selection procedures, revealed that there is a fairly steady fall in magnesium concentration as cells grow, terminating in a rapid influx of magnesium just before cell division. This leads to the hypothesis that falling magnesium concentration may act as a transducer of cell size, eventually triggering spindle formation and a membrane change which permits rapid uptake of magnesium to a concentration which brings about spindle breakdown. The hypothesis was tested directly using the divalent cation ionophore, A23187, in the absence of calcium ions; the results obtained showed that a short pulse of A23187, very late in the cell cycle, accelerated cells into division and shortened the subsequent cycle. The hypothesis is discussed in relation to current models of cell cycle regulation.
Link Reference:
http://jcs.biologists.org/cgi/content/abstract/42/1/329
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