A mutation in aspergillus nidulans producing hyphal walls which lack chitin

Katz, D.; Rosenberger, R. F.

doi:10.1016/0304-4165(70)90218-7

Cited by 60 publications

(36 citation statements)

References 23 publications

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“…Walls from the strains were purified from cells grown at 32°C and at 42°C in the presence of 1.0 M sorbitol. In agreement with previous reports (8,15,18,23,35), acid hydrolysis of walls and then thin-layer chromatography showed that the predominant carbohydrates in the wall preparations were glucose and glucosamine, with minor amounts of galactose and mannose (data not shown). Thus, the phenol-sulfuric acid assay which reacts with all three hexoses provides a slight overestimate of total glucan content.…”

Section: Resultssupporting

confidence: 93%

Characterization of Aspergillus nidulans mutants deficient in cell wall chitin or glucan

Borgia

Dodge

1992

J Bacteriol

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By screening for the osmotically remediable phenotype, mutations in two genes (orlA and or1B) affecting the cell wall chitin content of Aspergillus nidulans were identified. Strains carrying temperature-sensitive alleles of these genes produce conidia which swell excessively and lyse when germinated at restrictive temperatures. Growth under these conditions is remedied by osmotic stabilizers and by N-acetylglucosamine (GlcNAc). Remediation by GlcNAc suggests that the mutations affect early steps in the synthesis of chitin. Temperature and medium shift experiments indicate that the phenotype is the result of decreased synthesis rather than increased chitin degradation and that osmotic stabilizers act to stabilize a defective wall rather than to stabilize the gene product. Two genes, oriC and orlD, which affect cell wall j0-1,3-glucan content were also identified.Walls from strains carrying mutations in these genes exhibit normal amounts of a-1,3-glucan and chitin but reduced amounts of 03-1,3-glucan. As for the chitin-deficient mutants, orlC and orlD mutants spontaneously lyse on conventional media but are remedied by osmotic stabilizers. These results indicate that both chitin and I0-1,3-glucan are likely to contribute to the structural rigidity of the cell wall.The cell wall plays an important role in the growth and development of the fungi. In addition to its function as the primary osmotic barrier of the cell, the temporal and spatial regulation of wall polymer synthesis is critical to the morphogenesis of the cell types characteristic of many fungi. The architecture and synthesis of the cell walls of fungi are poorly understood. For a majority of the fungi, including most of those of medical and economic importance, chitin and/or P-1,3-glucans are believed to be the most important structural polysaccharides (3). Many studies of wall synthesis have concerned the enzymology of chitin synthase and, to a lesser extent, P-1,3-glucan synthase.In the yeasts or yeastlike fungi such as Saccharomyces cerevisiae, Candida albicans, and Schizosaccharomyces pombe, chitin is a relatively small fraction of the cell wall. In S. cerevisiae, chitin is found predominantly in the primary septa between cells (9, 10, 26). Three related genes (CHSJ, CHS2, and CALI) involved in chitin synthesis from S. cerevisiae (7,29,32) and one from C. albicans (1) have been sequenced. The finding that the CHSJ (chitin synthase 1) gene from S. cerevisiae, which codes for the major chitin synthase activity, could be disrupted without affecting chitin synthesis was unexpected (7). In addition, at least under some conditions, both the CHSJ and CHS2 genes can be disrupted without affecting the majority of chitin synthesis (5). Recently, a gene (CALl) with regions of homology to chitin synthases 1 and 2 and required for chitin synthase 3 activity was identified (32). Chitin synthase 3 was shown to be responsible for chitin synthesis in the portion of the wall not associated with the septum and to be responsible for the chitin ring formation which prec...

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Section: Resultssupporting

confidence: 93%

Characterization of Aspergillus nidulans mutants deficient in cell wall chitin or glucan

Borgia

Dodge

1992

J Bacteriol

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“…Results of Katz & Rosenberger with a temperature-sensitive mutant of Aspergillus nidular7s suggest that microfibrils may not in fact be the crucial factor which determines tip shape; the mutant could not synthesize glucosamine and therefore chitin at the restrictive temperature (Katz & Rosenberger, 1970). The walls of hyphae of the mutant grown at 41 "c contained only 7 to 15 yo of the normal chitin complement but maintained their normal shape when grown in medium containing an osmotic stabilizer or when transferred to buffer (Katz & Rosenberger, 1971).…”

Section: Discussionmentioning

confidence: 96%

Determination of Tip Shape in Fungal Hyphae

Saunders

Trinci

1979

Journal of General Microbiology

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“…It is known that the papulacandins and nikkomycins depress but do not completely halt the synthesis of beta-(1,3)-glucan and chitin, respectively (106,183). However, in studies described earlier in this review (22,23,133), temperature-sensitive mutants of A. nidulans that were completely blocked for either chitin or beta-(1,3)-glucan synthesis showed the same patterns of osmotically sensitive cells found when combinations of cilofungin and nikkomycin Z were used against A. fiumigatus (185).…”

Section: Combinations Of Cell Wall-active Substancesmentioning

confidence: 85%

“…Katz and Rosenberger, in a study published in 1970 (133), found that their mutant made reduced amounts of chitin but normal amounts of glucose at the restrictive temperature and grew without lysis only when the growth medium was osmotically stabilized. When an intermediate tonicity was used, swollen hyphae were produced.…”

Section: Filamentous Fungimentioning

confidence: 99%

Compounds active against cell walls of medically important fungi

Hector

1993

Clin Microbiol Rev

215

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A number of substances that directly or indirectly affect the cell walls of fungi have been identified. Those that actively interfere with the synthesis or degradation of polysaccharide components share the property of being produced by soil microbes as secondary metabolites. Compounds specifically interfering with chitin or beta-glucan synthesis have proven effective in studies of preclinical models of mycoses, though they appear to have a restricted spectrum of coverage. Semisynthetic derivatives of some of the natural products have offered improvements in activity, toxicology, or pharmacokinetic behavior. Compounds which act on the cell wall indirectly or by a secondary mechanism of action, such as the azoles, act against diverse fungi but are usually fungistatic in nature. Overall, these compounds are attractive candidates for further development.

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A mutation in aspergillus nidulans producing hyphal walls which lack chitin

Cited by 60 publications

References 23 publications

Characterization of Aspergillus nidulans mutants deficient in cell wall chitin or glucan

Characterization of Aspergillus nidulans mutants deficient in cell wall chitin or glucan

Determination of Tip Shape in Fungal Hyphae

Compounds active against cell walls of medically important fungi

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