STUDIES ON EXTRACELLULAR PROTEASE OF CRYPTOCOCCUS NEOFORMANS

• Project/Area Number: 06671839
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: Morphological basic dentistry
• Research Institution: NIPPON DENTAL UNEVERSITY
• Principal Investigator: AOKI Shigeji NIPPON DENTAL UNEVERSITY,SCHOOL OF DENTISTRY AT NIIGATA,ASSOCIATE PROFESSOR, 新潟歯学部, 助教授 (20095045)
• Co-Investigator(Kenkyū-buntansha): NAKAMURA Kenjirou NIPPON DENTAL UNEVERSITY,SCHOOL OF DENTISTRY AT NIIGATA,ASSISTANT, 新潟歯学部, 助手 (00227894) ; ITO Shoko (KUWA Shoko) NIPPON DENTAL UNEVERSITY,SCHOOL OF DENTISTRY AT NIIGATA,LECTURER, 新潟歯学部, 講師 (40095063)
• Project Period (FY): 1994 – 1995
• Project Status: Completed (Fiscal Year 1995)
• Budget Amount: ¥1,100,000 (Direct Cost: ¥1,100,000); Fiscal Year 1995: ¥400,000 (Direct Cost: ¥400,000); Fiscal Year 1994: ¥700,000 (Direct Cost: ¥700,000)
• Keywords: Cryptococccus neoformans / Extracellular protease / Growth / Bovine serum albumin / Pathogenic fungus

Research Abstract

Cryptococccus neoformans is a causative agent of human cryptococcosis. There have been few studies on extracellular protease of this species because this fungus has been considered to be nonproteolytic. In this study, we demonstrated that C.neoformans produced extracellular protease when cultured in solid and liquid media containing bovine serum albumin (BSA) as the sole source of nitrogen.
Strains used in this study were isolated from AIDS patients at the Infectious Disease Institute, University of Turin (Italy). Amon 8 strains examined, 7 strains belonged to serotype D and only one to serotype A,supporting the characteristic distribution of these serotypes in the temperate zone. Protease production by the strains were demonstrated with Yeast Carbon Base medium supplemeted with 0.1% BSA and 0.01% polypepton. Degradation and utilization of BSA by the fungal cells were demonstrated by gel-electrophoretic analysis of culture supematants. Substrate gel electrophoresis showed one proteolytic band with a very large molecular size, 120-150 kDa. The protease exhibited an optimum at pH 6.5-7.0, being neutral protease. The enzyme degraded actively azocoll and azocasein but showed a weak activity against azoalbumin. Inhibitor experiments have not yet succeeded in typing the cryptococcal protease.

Research Products

• [Publications] Ito-Kuwa,S.,Nakamura,K.,Aoki,S.,Ninomiya,K.,Kato,J. & Vidotto,V.: "Serotyping of Cryptococcus neformans isolated from AIDS patients." Odontology. 82. 360-364 (1994)
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] Aoki,S.,Ito-Kuwa,S.,Nakamura,K.,Kato,J. Ninomiya,K.,& Vidotto,V.: "Extracellular proteolytic activity of Cryptococcus neoformans." Mycopathologia. 128. 143-150 (1994)
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] Ito-Kuwa, S., Nakamura, K., Aoki, S., Ninomiya, K., Kato, J.and Vidotto, V.: "Serotyping of Cryptococcus neoformans isolated from AIDS patients." Odontology. 82 (2). 360-364 (1994)
  • Description: 「研究成果報告書概要(欧文)」より
• [Publications] Aoki, S., Ito-Kuwa, S., Nakamura, K., Kato, J., Ninomiya, K.and Vidotto, V.: "Extracclluar proteolytic activity of Cryptococcus neoformans." Mycopatologia. 128 (3). 143-150 (1994)
  • Description: 「研究成果報告書概要(欧文)」より
• [Publications] S.Ito-Kuwa et al.: "Serotyping of Cryprococcus neoformans isolated from AIDS patients." Odontology. 82. 360-364 (1994)
• [Publications] S Aoki.et al.: "Extracellular proteolytic activity of Cryptococcus neoformans." Mycopathologia. (3月掲載予定).