ABSTRACT
BACKGROUND: Trichoderma reesei is a filamentous fungus that is important as an industrial producer of cellulases and hemicellulases due to its high secretion of these enzymes and outstanding performance in industrial fermenters. However, the reduction of enzyme production caused by carbon catabolite repression (CCR) has long been a problem. Disruption of a typical transcriptional regulator, Cre1, does not sufficiently suppress this reduction in the presence of glucose. RESULTS: We found that deletion of an α-tubulin (tubB) in T. reesei enhanced both the amount and rate of secretory protein production. Also, the tubulin-disrupted (ΔtubB) strain had high enzyme production and the same enzyme profile even if the strain was cultured in a glucose-containing medium. From transcriptome analysis, the ΔtubB strain exhibited upregulation of both cellulase and hemicellulase genes including some that were not originally induced by cellulose. Moreover, cellobiose transporter genes and the other sugar transporter genes were highly upregulated, and simultaneous uptake of glucose and cellobiose was also observed in the ΔtubB strain. These results suggested that the ΔtubB strain was released from CCR. CONCLUSION: Trichoderma reesei α-tubulin is involved in the transcription of cellulase and hemicellulase genes, as well as in CCR. This is the first report of overcoming CCR by disrupting α-tubulin gene in T. reesei. The disruption of α-tubulin is a promising approach for creating next-generation enzyme-producing strains of T. reesei.
ABSTRACT
A 21-year-old man was admitted to our hospital in June 2015. He felt paresthesia of toes in April 2015, which had been spreading upward, and he became difficult to walk in June. Nerve conduction study showed peripheral demyelinating neuropathy that met the diagnostic criteria for chronic inflammatory demyelinating polyneuropathy (CIDP), and the cerebrospinal fluid (CSF) examination revealed the remarkably increased protein level. In addition, magnetic resonance imaging of his brain showed a few plaques in white matter, so he was finally diagnosed with combined central and peripheral demyelination (CCPD). Moreover, anti-neurofascin155 (NF155) antibodies assayed in his serum and CSF turned out to be positive. Although he was treated with intravenous immunoglobulin and intravenous methylprednisolone, his symptoms were not ameliorated. However, plasma exchange therapy was apparently effective, and the titer of anti-NF155 antibody was reduced. Recently, the number of case reports of CIDP with CNS lesions has gradually been increasing, while the information about the diagnosis and the treatment responses are not enough. Thus, we reported our case with CCPD who was successfully treated with plasma exchange.