L-asparaginase production was investigated in the filamentous fungi Aspergillus tamarii and Aspergillus terreus.The fungi were cultivated in medium containing different nitrogen sources. A. terreus showed the highest L-asparaginase (activity) production level (58 U/L) when cultivated in a 2% proline medium. Both fungi presented the lowest level of L-asparaginase production in the presence of glutamine and urea as nitrogen sources. These results suggest that L-asparaginase production by of filamentous fungi is under nitrogen regulation.Key words: filamentous fungi -production of L-asparaginase -Aspergillus tamarii -Aspergillus terreus Asparaginase (L-asparagine amido hydrolase, E.C. 3.5.1.1) is an anti-neoplastic agent, used in the lymphoblastic leukaemia chemotherapy. Neoplastic cells cannot synthetase L-asparagine due the absence of L-asparagine synthetase (Keating et al. 1993). For this reason the commonest therapeutic practice is to inject intravenously free enzyme in order to decrease the blood concentration of Lasparagine affecting selectively the neoplastic cells (Mitchell et al. 1994). However, L-asparaginase from bacterial origin can cause hypersensitivity in the long-term used, leading to allergic reactions and anaphylaxis (Reynolds & Taylor 1993). The search for other asparaginase sources, like eucaryotic microorganisms, can lead to an enzyme with less adverse effects. The importance of microorganisms as L-asparaginase sources has been focused since the time it was obtained from Escherichia coli and its antineoplastic activity demonstrated in guinea pig serum (Broome 1961, Mashburn & Wriston 1964, Roberts et al. 1966, Schawartz et al. 1966. The E. coli and Erwinia enzymes were isolated, purified, and experimentally used as an anti-leukaemic agent in human patients (Clavell et al. 1986, Story et al. 1993. It demonstrated high potential against children's acute lymphoblastic leukaemia (Hill et al. 1967, Oettgen et al. 1967. Several research groups have studied asparaginase production and purification in attempt to minimize impurities that produce allergenic reations , Boss 1997, Gallagher et al. 1999.It has been observed that eukaryote microorganisms like yeast and filamentous fungi have a potential for asparaginase production (Wade et al. 1971, Wiame et al.1985, Pinheiro et al. 2001 asparaginase (De-Angeli et al. 1970, Arima et al. 1972, Curran et al. 1985.L-asparaginase belongs to an amidase group that produces aspartic acid and ammonia by asparagine hydrolysis (Wriston & Yellin 1973, Capizzi et al. 1984. Here we present a simple and rapid assay method for the detection of asparaginase from different strains of Aspergillum, Penicillium, and Fusarium genera of fungi using the Gulati et al. (1997) method. After an initial screening, strains presenting high asparaginase activity were cultivated in submerged fermentation in order to determine the production of this enzyme in the presence of different nitrogen sources. Moreover the question whether asparaginase from filamentous fungi is nitrogen regulated a...

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Fifty isolates of Beauveria bassiana (Balsamo) Vuillemin, 1912 (Ascomycota: Clavicipitaceae) were analyzed by morphology, for their pathogenic potential to Boophilus microplus (Canestrini, 1887) (Acari: Ixodidae) larvae, and by Random Amplified Polymorphic DNA-Polymerase Chain Reaction technique. Morphological analysis demonstrated that isolates present characteristics compatible to those described for B. bassiana in the literature. Virulence test demonstrated that all isolates present lethal effect on larvae and that the lethal concentration varies among isolates. The most virulent isolate was the only one obtained from human infection, which was also the only isolate presenting synnemata. The study on genetic variability among the isolates allowed the identification of 23 electrophoretic profiles. The established groupings suggest that most of the isolates obtained from B. microplus of the same locality present low genetic variation. In this way, the data in the present study will contribute to a meticulous characterization of these B. bassiana isolates.

Uma série de novas Bases de Mannich (HL1-HL13) derivadas da 2-hidroxi-1,4-naftoquinona (lausona), benzaldeídos substituídos [C 6 = Bu) were determined by single crystal X-ray diffraction studies. All complexes crystallize in centrosymmetric space groups, with a copper atom in the inversion centre. Two L − coordinate through the naphthalen-2-olate oxygen and secondary amine-N atoms, forming sixmembered chelate rings around the copper atom in a trans-N 2 O 2 environment; spectroscopic data confirm that the other complexes exhibit similar molecular arrangement. The antimicrobial activity of all compounds has been tested on seven different strains of bacteria: Bacillus cereus, Bacillus subtilis, Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. In general, Mannich bases were more active than complexes, HL11 (R 1 = OH; R 2 =H; R 3 = Me; R 4 = Bn) and HL13 (R 1 = OH; R 2 = H; R 3 = Br; R 4 = Bn) being the most potent inhibitors. The MIC for the most active compound HL11 against S. Coli was 20 µmol L -1 (8 µg mL ) and well below most values reported for other naphthoquinones.

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