Cristina Y Kawano

Publications (2)3.71 Total impact

• Article: Biological activities from extracts of endophytic fungi isolated from Viguiera arenaria and Tithonia diversifolia.

  Denise O Guimarães, Warley S Borges, Cristina Y Kawano, Patrícia H Ribeiro, Gustavo H Goldman, Auro Nomizo, Otávio H Thiemann, Glaucius Oliva, Norberto P Lopes, Mônica T Pupo
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  ABSTRACT: A total of 39 endophytic fungi have been isolated from Viguiera arenaria and Tithonia diversifolia, both collected in São Paulo State, Brazil. The isolates were identified based on their ribosomal DNA sequences. The ethyl acetate (EtOAc) extracts of all endophytic fungi were evaluated for their antimicrobial, antiparasitic and antitumoral activity. Antimicrobial screening was conducted using an agar diffusion assay against three pathogenic microorganisms: Staphylococcus aureus, Escherichia coli and Candida albicans. Antiparasitic activity was determined by enzymatic inhibition of gGAPDH of Trypanosoma cruzi and adenine phosphorybosiltransferase (APRT) of Leishmania tarentolae. Antitumoral activity was tested against human T leukemia cells by the Mosmann colorimetric method. All extracts showed activity in at least one assay: 79.5% of the extracts were cytotoxic against leukemia cells, 5.1% of the extracts were active against S. aureus, 25.6% against E. coli and 64.1% against Candida albicans. Only one extract showed promising results in the inhibition of parasitic enzymes gGAPDH (95.0%) and three were found to inhibit APRT activity. The cytotoxic extract produced by the strain VA1 (Glomerella cingulata) was fractionated and yielded nectriapyrone and tyrosol. Nectriapyrone showed relevant cytotoxic activity against both human T leukemia and melanoma tumor cell lines.
  FEMS Immunology & Medical Microbiology 02/2008; 52(1):134-44. · 2.44 Impact Factor
• Article: Hyperbranching induced by cold-shock or snow-flake mutation in Neurospora crassa is prevented by addition of exogenous calcium.

  Cristina Y Kawano, Suraia Said
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  ABSTRACT: Hyphal tip growth is a highly polarized process of cell extension, which may be affected by chemical and physical stress. Neurospora crassa exposed to cold-shock lost its polarized growth and dichotomous branches were detected. These effects were not observed in the presence of 500 mM Ca2+. We compared here the morphological pattern of a snow-flake mutant (sn) and the wild-type (wt) exposed to 4 degrees C. Hyphal morphology, nuclei, actin and microtubule distribution were analyzed. No effects on sn hyphal morphology were detected at 4 degrees C. Exogenous Ca2+ converted sn to an essentially wt appearance. The results presented here suggest that sn mutation and cold-shock treatment have affected Ca2+ influx since addition of this cation to sn (30 degrees C) and to wt (4 degrees C) maintained polarized growth and normal nuclear and microtubules distribution.
  Journal of Basic Microbiology 02/2005; 45(3):199-206. · 1.27 Impact Factor