Heme synthesis in Crithidia deanei: Influence of the endosymbiote

1. 1. The activity of the following enzymes involved in the biosynthesis of porphyrins was determined in endosymbiote-free and endosymbiote-containing Crithidia deanei grown in a chemically defined medium: succinyl Coenzyme A synthetase (Suc.CoA-S), 5-aminolevulinate synthetase (ALA-S), 4,5-dioxovaleric acid transaminase (DOVA-T), 5-aminolevulinate dehydratase (ALA-D), por- phobilinogenase (PBGase), deaminase and heme synthetase (Heme-S). The amount of 5-aminolevulinic acid (ALA) and porphobilinogen, porphyrins and heme was also determined. 2. 2. ALA and PBG were detected in C. deanei. The levels of free porphyrins was low. Heme concentration was nil. 3. 3. The activity of ALA-D. deaminase and PBGase was not detected in C deanei. 4. 4. The activity of Suc.CoA-S and ALA-S were twice higher in symbiote-containing than in aposymbiotic C. deanei. Aposymbiotic cells had a higher activity of DOVA-T than symbiote-containing cells. 5. 5. The level of Heme-S, measured using protoporphyrin as substrate, was twice as high in symbiotecontaining than in symbiote-free cells,. © 1985.Fil:Salzman, T.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Del Batlle, C.A.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

ISOLATION and CHARACTERIZATION of A GLUCOCEREBROSIDE (MONOGLUCOSYLCERAMIDE) FROM SPOROTHRIX-SCHENCKII

UNIV FED RIO de JANEIRO,INST MICROBIOL,BR-21941 RIO de JANEIRO,RJ,BRAZILESCOLA PAULISTA MED,DISCIPLINA MICOL,BR-04023 São Paulo,SP,BRAZILESCOLA PAULISTA MED,DISCIPLINA MICOL,BR-04023 São Paulo,SP,BRAZILWeb of Scienc

CHANGES in CELL-SURFACE ANIONOGENIC GROUPS INDUCED BY PROPRANOLOL in HERPETOMONAS-MUSCARUM-MUSCARUM

UNIV FED RIO de JANEIRO, ILHA FDN, INST BIOFIS CARLOS CHAGAS FILHO, BR-21941 RIO de JANEIRO, RJ, BRAZILESCOLA PAULISTA MED, DEPT PHARMACOL, BR-01000 São Paulo, SP, BRAZILESCOLA PAULISTA MED, DEPT PHARMACOL, BR-01000 São Paulo, SP, BRAZILWeb of Scienc

DETECTION OF CELLULAR-IMMUNITY WITH THE SOLUBLE-ANTIGEN OF THE FUNGUS SPOROTHRIX-SCHENCKII IN THE SYSTEMIC FORM OF THE DISEASE

Sporothrix schenckii is the etiologic agent of sporotrichosis, a mycosis of world-wide distribution more commonly occurring in tropical regions. The immunological mechanisms involved in the prevention and control of sporotrichosis are not fully understood but apparently include both the humoral and cellular responses. In the present investigation, cellular immunity was evaluated by in vivo and in vitro tests in mice infected with yeast-like forms of S. schenckii. The disease developed systemically and cellular immunity was evaluated for a period of 10 weeks. The soluble antigen utilized in the tests was prepared from yeast form of the fungus through the sonication (20 min: 10 sonications at 50 W at 2-min intervals). Delayed hypersensitivity and lymphocyte transformation tests showed that the cellular immune response was depressed between the 4th and 6th week of infection when the animals were challenged with the soluble fungal antigen. This depression frequently indicates worsening of the disease, with greater involvement of the host. This is a promising field of research for a better understanding of the pathogeny of this mycosis

Identification of sialic acids on the cell surface of Candida albicans

The cell-surface expression of sialic acids in two isolates of Candida albicans was analyzed by thin-layer and gas chromatography, binding of lectins, colorimetry, sialidase treatment and flow cytofluorimetry with fluorescein-labeled lectins. N-acetylneuraminic acid (NANA) was the only derivative found in both strains of C. albicans grown in a chemically defined medium. Its identification was confirmed by mass spectrometry in comparison with an authentic standard. the density of sialic acid residues per cell ranged from 1.6x10(6) to 2.8x10(6). the surface distribution of sialic acids over the entire C. albicans was inferred from labeling with fluorescein-Limulus polyphemus and Limax flavus agglutinins and directly observed by optical microscopy with (FITC)-Sambucus nigra agglutinin (SNA), abrogated by previous treatment of yeasts with bacterial sialidase. Sialidase-treated yeasts generated beta-galactopyranosyl terminal residues that reacted with peanut agglutinin. in C. albicans N-acetyl-neuraminic acids are alpha 2,6- and alpha 2,3-linked as indicated by yeast binding to SNA and Maackia amurensis agglutinin. the alpha 2,6-linkage clearly predominated in both strains. We also investigated the contribution of sialic acids to the electronegativity of C. albicans, an important factor determining fungal interactions in vivo. Adhesion of yeast cells to a cationic solid phase substrate (poly-L-lysine) was mediated in part by sialic acids, since the number of adherent cells was significantly reduced after treatment with bacterial sialidase. the present evidence adds C. albicans to the list of pathogenic Fungi that synthesize sialic acids, which contribute to the negative charge of fungal cells and have a role in their specific interaction with the host tissue. (C) 2000 Elsevier Science B.V. All rights reserved.Univ Fed Rio de Janeiro, Inst Microbiol Prof Paulo Goes, Dept Microbiol Geral, BR-21941590 Rio de Janeiro, BrazilUniversidade Federal de São Paulo, Disciplina Biol Celular, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, Disciplina Biol Celular, BR-04023062 São Paulo, BrazilWeb of Scienc