Catabolite repression of inductive polygalacturonase synthesis in Penicillium expansum by sucrose

✍ Scribed by Roberta Hilsdorf Piccoli-Valle; Maria Cristina Baracat-Pereira; Dr. Daison Olzany Silva

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 268 KB
• Volume: 35
• Category: Article
• ISSN: 0233-111X
• DOI: 10.1002/jobm.3620350312

✦ Synopsis

Polygalacturonase (PG) synthesis by the fungus Penicillium expansum in the presence of a combination of pectin and sucrose corresponding to 0.3% of the substrate was repressed more intensely by increasing sucrose concentrations and decreasing pectin concentrations. PG synthesis was partially repressed when sucrose was added 6 or 12 h after the beginning of culture and fully repressed when sucrose was added at the beginning of culture. Tests with actidione indicated that repression by sucrose occurs at the transcription level. We suggest that an accumulation of messenger RNA occurred when the fungus was cultured for 36 h in 0.3% pectin and actidione since, after being washed and reincubated in actidione-free medium in the presence of the repressor, the fungus synthesized PG up to 54 h of culture, when a reduction in accumulated messenger RNA and PG synthesis occurred. Repression by sucrose was reversible since the fungus started synthesizing PG again in the absence of the repressor and in the presence of the inducer.