Polyoxin D Inhibits Colloidal Gold--Wheat Germ Agglutinin Labelling of Chitin in Dimorphic Forms of Candida albicans

Hilenski, Lula; Naider, Fred; Becker, Jeffrey M.

doi:10.1099/00221287-132-6-1441

Cited by 20 publications

(13 citation statements)

References 43 publications

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“…In the presence of nikkomycin the protoplasts formed walls which were not labelled by Au-WGA, although the Con A-fe receptors were present as well as some electron-transparent material ( Fig. 3 4 , confirming that in the presence of this antibiotic chitin was not synthesized but the S-glucan (Table 1) was able to form an abnormal wall (Hilenski et al, 1986).…”

Section: Ultrastructural Studiesmentioning

confidence: 66%

“…The walls showed a thick electron-transparent layer with many Con A receptors on both surfaces. The Au-WGA receptors seemed to be located preferentially in the inner part of the wall extending to the nearby transparent layer as observed in whole cells (Hilenski et al, 1986). The two surfaces seemed to be enriched in glycoproteins, as Con A-fe markers were present in high amounts (Fig.…”

Section: Ultrastructural Studiesmentioning

confidence: 93%

“…The architecture of the cell walls is not well defined (FarkaS, 1985), but it has been described as being a multilayered structure (Cassone et al, 1979;Hilenski et al, 1986) with a fine network of microfibrils, probably chitin, in its inner part (Tronchin et al, 1981;Kopecka, 1984).…”

Section: Introductionmentioning

confidence: 99%

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Formation of a New Cell Wall by Protoplasts of Candida albicans: Effect of Papulacandin B, Tunicamycin and Nikkomycin

Elorza

Murgui²,

Rico³

et al. 1987

Microbiology

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Incorporation of polysaccharides into the walls of regenerating protoplasts of Candida albicans was followed in the presence of papulacandin B, tunicamycin and nikkomycin. With the first drug, chitin was incorporated normally whereas incorporation of glucans and mannoproteins was significantly decreased. Tunicamycin decreased incorporation of all wall polymers when added at the beginning of the regeneration process but blocked only mannan and alkaliinsoluble glucan incorporation when added after 5 h. Nikkomycin inhibited chitin synthesis, and the walls formed by the protoplasts were enriched in alkali-soluble glucan. Pulse-chase experiments suggested that a precursor-product relationship between the alkali-soluble and alkali-insoluble glucans existed in the wall. The results obtained with the antibiotics were confirmed and extended by cytological studies using wheat-germ agglutinin labelled with colloidal gold and concanavalin A-ferri tin as specific markers of chitin and mannoproteins respectively. The results support the idea that regeneration of walls by protoplasts occurs in two steps : firstly, a chitin microfibrillar skeleton is formed, and in a later step glucan-mannoprotein complexes are added to the growing structure. The chitin skeleton probably allows the orderly spatial arrangement of the other polymers giving rise to the regenerated cell wall.

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Section: Ultrastructural Studiesmentioning

confidence: 66%

Section: Ultrastructural Studiesmentioning

confidence: 93%

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Formation of a New Cell Wall by Protoplasts of Candida albicans: Effect of Papulacandin B, Tunicamycin and Nikkomycin

Elorza

Murgui²,

Rico³

et al. 1987

Microbiology

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“…To establish if septa contained chitin, TEM thin sections were stained with WGA (Hilenski et al, 1986;Tronchin et al, 1981;. Unstained ultrathin sections were mounted on 300 mesh nickel grids (Agar Scientific Ltd, Essex, UK) and labeled with 10 nm WGA-colloidal gold particles (British Biocell International Ltd, Cardiff, UK).…”

Section: Lectin Colloidal Gold Staining Of Chitinmentioning

confidence: 99%

Cell wall stress induces alternative fungal cytokinesis and septation strategies

Walker

Lenardon

Preechasuth

et al. 2013

Journal of Cell Science

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SummaryIn fungi, as with all walled organisms, cytokinesis followed by septation marks the end of the cell cycle and is essential for cell division and viability. For yeasts, the septal cross-wall comprises a ring and primary septal plate composed of chitin, and a secondary septum thickened with b(1,3)-glucan. In the human pathogen Candida albicans, chitin synthase enzyme Chs1 builds the primary septum that is surrounded by a chitin ring made by Chs3. Here we show that the lethal phenotype induced by repression of CHS1 was abrogated by stress-induced synthesis of alternative and novel septal types synthesized by other chitin synthase enzymes that have never before been implicated in septation. Chs2 and Chs8 formed a functional salvage septum, even in the absence of both Chs1 and Chs3. A second type of salvage septum formed by Chs2 in combination with Chs3 or Chs8 was proximally offset in the mother-bud neck. Chs3 alone or in combination with Chs8 formed a greatly thickened third type of salvage septum. Therefore, cell wall stress induced alternative forms of septation that rescued cell division in the absence of Chs1, demonstrating that fungi have previously unsuspected redundant strategies to enable septation and cell division to be maintained, even under potentially lethal environmental conditions.

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“…Hector and Pappagianis (109) found that immature spherules of Coccidioides immitis were highly and rapidly susceptible to the effects of polyoxin D, exhibiting morphologic effects consistent with an osmotically sensitive state. Withincopy, treatment of both yeast and mycelial forms of C. albicans with polyoxin D led to the disappearance of chitin in the inner cell wall layers and a lack of septum formation (115). With prolonged incubation, the successive cells in a chain grew progressively larger and had thinner walls, suggesting that chitin also plays a role in maintaining the structural integrity of the entire wall.…”

Section: Compounds Active Against Fungal Cell Walls Inhibitors Of Chimentioning

confidence: 99%

Compounds active against cell walls of medically important fungi

Hector

1993

Clin Microbiol Rev

217

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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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Polyoxin D Inhibits Colloidal Gold--Wheat Germ Agglutinin Labelling of Chitin in Dimorphic Forms of Candida albicans

Cited by 20 publications

References 43 publications

Formation of a New Cell Wall by Protoplasts of Candida albicans: Effect of Papulacandin B, Tunicamycin and Nikkomycin

Formation of a New Cell Wall by Protoplasts of Candida albicans: Effect of Papulacandin B, Tunicamycin and Nikkomycin

Cell wall stress induces alternative fungal cytokinesis and septation strategies

Compounds active against cell walls of medically important fungi

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