Document Detail


Osmotic stress-coupled maintenance of polar growth in Aspergillus nidulans.
MedLine Citation:
PMID:  11918796     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Free-living cells monitor extracellular 'osmotic strength' and respond metabolically to offset unfavourable osmotic intracellular solute concentrations. Here, we report the reconstruction of the Aspergillus nidulans salt stress-controlling MAP kinase pathway, based on homology analysis with known yeast genes. In A. nidulans, salt stress HOG genes, such as pbsA, hogA, ptpA and msnA, are upregulated when exposed to high concentrations of salt and, in a hogA deletion mutant (SIK1), the accumulation of pbsA is strongly reduced, suggesting a salt-specific feedback induction mechanism. Growth of SIK1 appears to be unchanged in unstressed cells, but hyphal extension rates are reduced by as much as 60% in the presence of salt. Microscopic observation revealed abnormal hyperbranched hyphal tips, disproportionate accumulation of nuclei and absence of septa. Thus, the inability to maintain turgor pressure depresses cell expansion and results in slower volume increases. In addition, SIK1 fails to partition the apical cell; thus, nuclei are not likely to arrest mitosis in interphase as in normal cells, but continue to divide, accumulating to high levels.
Authors:
Kap-Hoon Han; Rolf A Prade
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Molecular microbiology     Volume:  43     ISSN:  0950-382X     ISO Abbreviation:  Mol. Microbiol.     Publication Date:  2002 Mar 
Date Detail:
Created Date:  2002-03-28     Completed Date:  2002-08-02     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  8712028     Medline TA:  Mol Microbiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  1065-78     Citation Subset:  IM    
Affiliation:
Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA.
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MeSH Terms
Descriptor/Qualifier:
Aspergillus nidulans / genetics,  growth & development*,  physiology*
Culture Media
Fungal Proteins / genetics*,  metabolism
Gene Expression Regulation, Fungal*
Heat-Shock Response*
Microscopy, Fluorescence
Mitogen-Activated Protein Kinases / genetics,  metabolism
Osmotic Pressure
Sodium Chloride / pharmacology
Chemical
Reg. No./Substance:
0/Culture Media; 0/Fungal Proteins; 7647-14-5/Sodium Chloride; EC 2.7.11.24/Mitogen-Activated Protein Kinases

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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