Calcofluor-allied optical brightener Rylux BSU stimulated spore germination rate in Trichophyton mentagrophytes and Aspergillus fumigatus both if supplemented into Sabouraud glucose agar and if used for pretreatment of spore suspension prior to inoculation at low concentrations. Maximum stimulation of germination was obtained if 0.2% Rylux BSU was used for pretreatment in aqueous solution for 1 d prior to inoculation (130% in T. mentagrophytes and 150% in A. fumigatus, respectively). Pretreatment with 1% Rylux BSU provided strong protection against UV-irradiation and resulted in increased yields of cultural variants after UV-irradiation.

• MeSH
• Aspergillus fumigatus drug effects   growth & development   metabolism   radiation effects   MeSH
• Benzenesulfonates pharmacology   MeSH
• Fluorescent Dyes MeSH
• Culture Media MeSH
• Microscopy, Electron, Scanning MeSH
• Spores, Fungal growth & development   MeSH
• Trichophyton drug effects   growth & development   metabolism   radiation effects   MeSH
• Ultraviolet Rays MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Benzenesulfonates MeSH
• Fluorescent Dyes MeSH
• Culture Media MeSH
• Rylux BSU MeSH Browser

Rylux BSU and congo red bind to chitin, interfere with proper cell-wall assembly, and stimulate chitin synthesis by increasing, most probably, chitin synthase 3 (ChS3) levels in Saccharomyces cerevisiae. On the other hand, the antibiotic nikkomycin Z inhibits chitin synthesis competitively. As ChS3 is the critical target of nikkomycin Z, its effect was tested in cells inhibited in growth by Rylux BSU or Congo red. Nikkomycin Z counteracted this inhibition but did not counteract aberrant cell-wall formation. These results indicate that chitin synthesis stimulation is the key step in Rylux BSU and congo red inhibition and support the idea that increase in chitin synthesis represents a compensatory response to damaged cell-wall structure. As Rylux BSU and congo red bind to newly synthesized chitin, further damage is caused in the wall and the response works in this case contrariwise. Nikkomycin Z breaks this vicious circle by counteracting the chitin synthesis stimulation.

• MeSH
• Aminoglycosides * MeSH
• Anti-Bacterial Agents pharmacology   MeSH
• Coloring Agents pharmacology   MeSH
• Benzenesulfonates pharmacology   MeSH
• Cell Wall drug effects   metabolism   ultrastructure   MeSH
• Chitin biosynthesis   MeSH
• Microscopy, Electron MeSH
• Fluorescent Dyes pharmacology   MeSH
• Congo Red pharmacology   MeSH
• Saccharomyces cerevisiae drug effects   growth & development   metabolism   ultrastructure   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Aminoglycosides * MeSH
• Anti-Bacterial Agents MeSH
• Coloring Agents MeSH
• Benzenesulfonates MeSH
• Chitin MeSH
• Fluorescent Dyes MeSH
• Congo Red MeSH
• nikkomycin MeSH Browser
• Rylux BSU MeSH Browser

The fluorescence brightener Rylux BSU (RBSU) showed an affinity for polysaccharide components of cell walls and accumulated in the extension zones of hyphal apices in Basidiobolus ranarum. It inhibited the polarized growth of mycelial hyphae and induced isotropic growth resulting in spherical thick-walled cells up to 456 microm in diameter. On the inner cell wall surface, massive protuberances were formed. The cell wall and protuberances were positive in PAS and the Grocott method and stained with fluorochromes Blankophor BA, Calcofluor, Uvitex 2B, Rylux BSU and FITC-labeled WGA- and ConA-lectins. The WGA-FITC fluorescence intensity of the wall's outermost layer, if not connected with neighbouring cells, and the fluorescence intensity of the innermost layer and of some protuberances mainly in their apical parts were on the average twice higher than the fluorescence intensity of the remaining wall material. RBSU binding to the cell wall material was stable. The process of converting from polarized to isotropic growth was reversible, depending upon contact with RBSU-containing medium. Repeated transfers of cells from RBSU-containing medium to an RBSU-free medium resulted in the development of apical swollen dumbbell-shaped cells.

• MeSH
• Benzenesulfonates pharmacology   MeSH
• Fluorescent Dyes pharmacology   MeSH
• Fungi cytology   drug effects   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Benzenesulfonates MeSH
• Fluorescent Dyes MeSH
• Rylux BSU MeSH Browser