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Search Results: 1 - 10 of 1502 matches for " Suraia Said "
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Modulation of biological activities produced by an endophytic fungus under different culture conditions  [PDF]
Henrique Pereira Ramos, Suraia Said
Advances in Bioscience and Biotechnology (ABB) , 2011, DOI: 10.4236/abb.2011.26065
Abstract: The effect of culture conditions on the production of bioactive secondary metabolites by the endophytic fungus Arthrinium State of Apiospora Montagnei Sacc. was investigated. Culture broths were partitioned with ethyl acetate and the resulting extracts were evaluated for antibacterial, antifungal, cytotoxic, and antiparasitic activities. The highest levels of activities were arisen from cultures cultivated at 30C in modified Czapek medium. The best antimicrobial activity against Escherichia coli and Pseudomonas aeruginosa (MIC 90 μg/ml), and against Aspergillus fumigatus (MIC 130 μg/ml) were found in extracts from cultures grown in medium containing 3.1% (w/v) sucrose and 0.1% (w/v) sodium nitrate at pH 4.0 after 9 days of incubation. Cultures grown in medium without modification also showed antiparasitic and antitumoral activities after 9 days at pH 4.0, antifungal activity against Candida albicans at pH 4.0 - 7.0 (MIC 140 μg/ml), but against A. fumigatus just after 27 days of incubation. A specific bioactive compound may have its production improved if the culture conditions parameters that affect or influence the production were known, which in turn makes the purification process easier.
The Difference in Calcium Levels in Aspergillus nidulans Grown on Glucose or Pectin  [PDF]
Janice Aparecida Rafael, Suraia Said
Advances in Microbiology (AiM) , 2012, DOI: 10.4236/aim.2012.22016
Abstract: Understanding the growth regulatory mechanisms in filamentous fungi is very important for the production of medicines for antifungal therapies. It is well established that Ca2+ gradient is essential for hyphal growth and that one mechanism responsible for the Ca2+ cellular concentration starts with the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) by receptor-regulated forms of phosphoinositide-specific phospholipase C (PI-PLC). In the present study the levels of calcium in Aspergillus nidulans wild type (A26) and plcA-deficient mutant (AP27) growing in a carbon source readily assimilated, as glucose or pectin a non-readily assimilated carbon source was investigated. Intracellular calcium levels in A26 were higher in the presence of glucose than in pectin, but lower in AP27 independently of the carbon source and in AP27 the vesicular calcium distribution occurred mainly at the apex of the hyphae. Delay in nuclear division was also observed if A26 and AP27 were grown in pectin presence when compared with growth in glucose. For the first time, it is demonstrated that the levels of intracellular Ca2+ were higher when A. nidulans was growing in glucose than in a non readily assimilated carbon source as pectin. Further, it also showed that the plcA gene, although not essential, may be responsible for high-molecular weight carbon source recongnation, for the intracellular Ca2+ levels maintenance and consequently by the nuclear division in A. nidulans.
Purification and Biochemical Characterization of Native and Pegylated Form of L-Asparaginase from Aspergillus terreus and Evaluation of Its Antiproliferative Activity  [PDF]
Claudio Battiston Loureiro, Kleiton Silva Borges, Augusto Faria Andrade, Luiz Gonzaga Tone, Suraia Said
Advances in Microbiology (AiM) , 2012, DOI: 10.4236/aim.2012.22019
Abstract: L-asparaginase is a chemotherapeutic drug used in the treatment of lymphoblastic leukemia. In the present study, the extracellular L-asparaginase produced by strain (PC-1.7A) of Aspergillus terreus was purified, characterized, and modified with polyethylene glycol. Moreover, its antiproliferative activity was evaluated. The apparent molecular weight of the enzyme was found to be 136 kDa. The optimal pH and temperature for the enzyme were 9.0℃ and 40℃, respectively. The enzyme retained 100% of the activity at 40℃ for 120 min. Pegylated L-asparaginase was more thermostable and more resistant to trypsin than native enzyme. Native L-asparaginase against human normal cells did not show cytotoxicity. However, in the leukemia cell lines RS4;11 and HL60 the antiproliferative effects of native L-asparaginase were observed after 96 and 72 h of incubation, respectively. For the first time, an L-asparaginase from fungus was evaluated as an antitumor agent in human cells lines and further investigations should be conducted to improve the knowledge about this enzyme.
Hyphal Morphology and Elongation Alterations in Aspergillus nidulans Provoked by the Diterpene Kaurenoic Acid  [PDF]
Janice A. Rafael, Nilton S. Arakawa, Sérgio R. Ambrosio, Fernando B. Da Costa, Suraia Said
Advances in Microbiology (AiM) , 2013, DOI: 10.4236/aim.2013.35059

Kaurenoic acid (KA), a kaurane-type diterpene extracted from leaves of Mikania hirsutissima, was previously reported as an inhibitor of vascular contractility mainly by blocking extracellular Ca2+ influx. The compound is known for several other biological activities such as antiparasitic, antispasmodic and antibacterial activity. The aim of the present study was to investigate the effect of KA on Aspergillus nidulans. KA (0.3 mM) showed fungistatic activity against A. nidulans with visible hyphal elongation and morphology damage. These effects were reverted by CaCl2 addition showing that KA interferes with intracellular Ca2+ gradient in A. nidulans. This is the first report on the mechanism of action of KA involving calcium levels by altering the elongation of fungi hyphae.

Effect of benzene compounds from plants on the growth and hyphal morphology in Neurospora crassa
Neves, Fabrícia Mendon?a;Kawano, Cristina Yoshiko;Said, Suraia;
Brazilian Journal of Microbiology , 2005, DOI: 10.1590/S1517-83822005000200016
Abstract: the effects of the benzene compounds from plants, respectively cinnamic acid, coumaric acid, ferulic acid, caffeic acid, and cinnamic aldehyde on growth and hyphal morphology of neurospora crassa, were investigated. cinnamic acid, ferulic acid and cinnamic aldehyde inhibited colony growth, but produced no visible alterations on hyphae. caffeic acid and coumaric acid did not inhibit growth, but changed hyphal morphology. the results suggest that caffeic and coumaric acids probably affect polarity maintenance (the continued deposition of wall material at the extending tip), while cinnamic aldehyde, ferulic and cinnamic acids decrease growth rate, but did not change hyphal polarity. the actin cytoskeleton and the spitzenk?rper appeared diffuse and not clearly visible when one of the benzene compounds was present in the culture.
Antimicrobial activity from endophytic fungi Arthrinium state of Apiospora montagnei Sacc. and Papulaspora immersa
Ramos, Henrique Pereira;Braun, Glaucia Hollander;Pupo, M?nica Tallarico;Said, Suraia;
Brazilian Archives of Biology and Technology , 2010, DOI: 10.1590/S1516-89132010000300017
Abstract: papulaspora immersa and arthrinium state of apiospora montagnei sacc. were isolated from the roots of smallanthus sonchifolius (yacón). the crude extracts from their cultures inhibited the growth of staphylococcus aureus, kocuria rhizophila, pseudomonas aeruginosa and escherichia coli. the more relevant results were observed in the ethyl acetate extract from p immersa against p aeruginosa (90 μg/ml) and ethyl acetate extract from arthrinium state of a montagnei sacc. against p aeruginosa (160 μg/ml). the two endophytic fungi isolated from yacón roots as well as their antimicrobial activity detected in the crude extracts cultures were being reported for the first time.
Biotransformation of a tetrahydrofuran lignan by the endophytic fungus Phomopsis Sp.
Verza, Michelle;Arakawa, Nilton S.;Lopes, Norberto P.;Kato, Massuo J.;Pupo, M?nica T.;Said, Suraia;Carvalho, Ivone;
Journal of the Brazilian Chemical Society , 2009, DOI: 10.1590/S0103-50532009000100029
Abstract: the biotrasformation of the tetrahydrofuran lignan, (-)-grandisin, by the endophitic fungus phomopsis sp, obtained from viguiera arenaria, led to the formation of a new compound determined as 3,4-dimethyl-2-(4'-hydroxy-3',5'-dimethoxyphenyl)-5-methoxy-tetrahydrofuran. the metabolite was evaluated against the parasite trypanosoma cruzi, the causative agent of chagas's disease, and showed a trypanocidal activity (ic50 9.8 μmol l-1) similar to the natural precursor (ic50 3.7 μmol l-1).
Partial purification and characterization of exopolygalacturonase II and III of Penicillium frequentans
Barense, Renata I.;Chellegatti, Maria Angélica dos S.C.;Fonseca, Maria José V.;Said, Suraia;
Brazilian Journal of Microbiology , 2001, DOI: 10.1590/S1517-83822001000400014
Abstract: previous studies from our laboratory have demonstrated that the fungus penicillium frequentans produces high levels of polygalacturonase and pectinesterase. endopolygalacturonase i (endo-pg i) and exopolygalacturonase i (exo-pg i) were previously purified and characterized. in the present study two extracellular polygalacturonases were separated, partially purified and biochemically characterized. both were characterized as exopolygalacturonases so they were named exopolygalacturonase ii (exo-pg ii) and exopolygalacturonase iii (exo-pg iii) which had a molecular mass of 63 kda (exo-pg ii) and 79 kda (exo-pg iii). the km values were 1.6 and 0.059 g/l and the vmax values were 2571 and 185 u/mg, respectively. the optimum temperature was 50oc for both enzymes, while the optimum ph was 5.0 for exo-pg ii and 5.8 for exo-pg iii.
Partial purification and characterization of exopolygalacturonase II and III of Penicillium frequentans
Barense Renata I.,Chellegatti Maria Angélica dos S.C.,Fonseca Maria José V.,Said Suraia
Brazilian Journal of Microbiology , 2001,
Abstract: Previous studies from our laboratory have demonstrated that the fungus Penicillium frequentans produces high levels of polygalacturonase and pectinesterase. Endopolygalacturonase I (Endo-PG I) and Exopolygalacturonase I (Exo-PG I) were previously purified and characterized. In the present study two extracellular polygalacturonases were separated, partially purified and biochemically characterized. Both were characterized as exopolygalacturonases so they were named exopolygalacturonase II (Exo-PG II) and exopolygalacturonase III (Exo-PG III) which had a molecular mass of 63 kDa (Exo-PG II) and 79 kDa (Exo-PG III). The Km values were 1.6 and 0.059 g/L and the Vmax values were 2571 and 185 U/mg, respectively. The optimum temperature was 50oC for both enzymes, while the optimum pH was 5.0 for Exo-PG II and 5.8 for Exo-PG III.
Personality Traits and Performance: The Mediating Role of Adaptive Behavior in Call Centers  [PDF]
Said Echchakoui
American Journal of Industrial and Business Management (AJIBM) , 2013, DOI: 10.4236/ajibm.2013.31003

Personality traits and adaptive behavior are central issues in research on call center performance. However, the current literature offers little guidance on the relationship between personality traits and adaptive behavior and how they work together to enhance employee performance. This study investigates the mediating role of adaptive behavior between Five-Factor traits and employee performance with customers. Empirical evidence from a Canadian call center supports this proposition for three Five-Factor traits. Managerial implications are discussed.

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