Vanessa Souza | Universidade Federal Rural de Pernambuco (original) (raw)

Papers by Vanessa Souza

Food Chemistry, 2011

This paper describes a simple method for mercury speciation in seafood samples by LC-ICP-MS with ... more This paper describes a simple method for mercury speciation in seafood samples by LC-ICP-MS with a fast sample preparation procedure. Prior to analysis, mercury species were extracted from food samples with a solution containing mercaptoethanol, L-cysteine and HCl and sonication for 15 min. Separation of mercury species was accomplished in less than 5 min on a C8 reverse phase column with a mobile phase containing 0.05%-v/v mercaptoethanol, 0.4% m/v L-cysteine and 0.06 mol L À1 ammonium acetate. The method detection limits were found to be 0.25, 0.20 and 0.1 ng g À1 for inorganic mercury, ethylmercury and methylmercury, respectively. Method accuracy is traceable to Certified Reference Materials (DOLT-3 and DORM-3) from the National Research Council Canada (NRCC). With the proposed method there is a considerable reduction of the time of sample preparation. Finally, the method was applied for the speciation of mercury in seafood samples purchased from the Brazilian market.

Chemical Product and Process Modeling, 2009

... Vanessa Ribeiro Souza, Federal University of São Carlos ... Algorithm Edson Romano Nucci,Vane... more ... Vanessa Ribeiro Souza, Federal University of São Carlos ... Algorithm Edson Romano Nucci,Vanessa Ribeiro Souza, Rosineide Gomes Silva, Giann Braune Reis, Raquel Lima Camargo Giordano, Roberto Campos Giordano, and Antonio José Gonçalves Cruz Abstract ...

Bioprocess and Biosystems Engineering, 2007

Penicillin G acylase (PGA) is one of the most important enzymes for the pharmaceutical industry. ... more Penicillin G acylase (PGA) is one of the most important enzymes for the pharmaceutical industry. Bacillus megaterium has the advantage of producing extra-cellular PGA. This work compares two neural networks (NNs) architectures for on-line inference of B. megaterium cell mass in an aerated stirred tank bioreactor, during the production of PGA. Nowadays, intelligent computing tools such as artificial NNs and fuzzy logic are commonly applied for state inference and modeling of bioreactors. Combining these two approaches in hybrid, neuro-fuzzy systems, may be advantageous. Our results indicate that a neuro-fuzzy inference system showed a better performance to infer cell concentrations, when compared to multilayer perceptrons networks.

Brazilian Archives of Biology and Technology, 2005

The purpose of this work was to characterize the enzyme penicillin G acylase (PGA) produced by Ba... more The purpose of this work was to characterize the enzyme penicillin G acylase (PGA) produced by Bacillus megaterium. Purification of the enzyme by ultra/diafiltration did not allow the detection of the PGA band by SDS-PAGE electrophoresis due to the high content of remaining proteins. However, using the DNA of the microorganism, it was possible to replicate the genes of the two B. megaterium PGA reported in literature, showing that the enzyme consisted of two sub-units, having 245 and 537 amino acids each and an average molecular mass of 26950 and 59070 Da, respectively. The parameters studied were: 1) the influence of temperature in the 25-600C range, 2) pH in the 5-10 range and 3) substrate concentration, this was tested to obtain results on the Penicillin G hydrolysis reaction rate, using the initial velocities approach. The maximum hydrolysis rate was obtained at 37ºC and pH 8.0. The Michaelis-Menten model fitted well, resulting in estimated Km and Vmax parameters values of 1.83 mM and 0.165*10-3 mmol/min/UI, respectively.

Bioorganic & Medicinal Chemistry Letters, 2005

Five (À)-cubebin derivative compounds, (À)-O-acetyl cubebin (3), (À)-O-benzyl cubebin (4), (À)-O-... more Five (À)-cubebin derivative compounds, (À)-O-acetyl cubebin (3), (À)-O-benzyl cubebin (4), (À)-O-(N,N-dimethylaminoethyl)-cubebin (5), (À)-hinokinin and (À)-6,6 0 -dinitrohinokinin , previously synthesised by our research group, were evaluated on in vitro assay against free amastigote forms of Trypanosoma cruzi, the asogic agent of ChagasÕ disease. It was observed that 6 was the most active compound (IC 50 = 0.7 lM), and that 4 and 5 displayed moderate activity against the parasite, giving IC 50 values of 5.7 and 4.7 lM, respectively. In contrast, it was observed that compound 3 was inactive and that 7 displayed low activity with IC 50 values of ffi1.5 · 10 4 and 95.3 lM, respectively.

Revista Brasileira De Farmacognosia-brazilian Journal of Pharmacognosy, 2008

There are a great number of medicinal plants without any scientific confirmation about their effi... more There are a great number of medicinal plants without any scientific confirmation about their efficacy and safety. This paper is a short review about two medicinal plants, "boldo do chile" (Peumus boldus) and "carqueja" (Baccharis genistelloides). Pharmacological studies have confirmed several popular indications for P. boldus and B. genistelloides, besides have established a relationship between isolated compounds from these extracts and the pharmacological effects observed. On the other hand, toxicological researches have pointed out that P. boldus tea should not be consumed during a long period (potential hepatotoxicity) and by pregnant, especially during the first three months. Moreover, B. genistelloides tea must be prohibited for pregnant because of confirmed abortive action, and for patients using medicines for blood pressure disorders. These studies point out the continuous necessity of more studies about medicinal plants; only with this knowledge it will be possible a safe and efficient use.

Bioorganic & Medicinal Chemistry Letters, 2005

The anti-inflammatory and analgesic effects of three dibenzylbutyrolactone lignans, (À)-hinokinin... more The anti-inflammatory and analgesic effects of three dibenzylbutyrolactone lignans, (À)-hinokinin (2), (À)-6,6 0 -dinitrohinokinin (3), and (À)-6,6 0 -diaminohinokinin (4), obtained by partial synthesis from (À)-cubebin (1), were investigated using different animal models. It was observed that compounds and inhibited the edema formation in the rat paw edema assay at the same level and that all responses were dose dependent. Also, at the dose of 30 mg/kg, compounds 1, 2, 3, and 4 inhibited the edema formation by 53%, 63%, 54%, and 82%, respectively, at the third hour of the experiment. In the acetic acid-induced writhing test in mice, compounds 2 and 4 produced inhibition levels of 97% and 92%, respectively, while 3 displayed lower effect (75%), which was still higher than 1. The assayed compounds neither displayed activity in the cell migration test nor in the hot plate test.

Food Chemistry, 2011

This paper describes a simple method for mercury speciation in seafood samples by LC-ICP-MS with ... more This paper describes a simple method for mercury speciation in seafood samples by LC-ICP-MS with a fast sample preparation procedure. Prior to analysis, mercury species were extracted from food samples with a solution containing mercaptoethanol, L-cysteine and HCl and sonication for 15 min. Separation of mercury species was accomplished in less than 5 min on a C8 reverse phase column with a mobile phase containing 0.05%-v/v mercaptoethanol, 0.4% m/v L-cysteine and 0.06 mol L À1 ammonium acetate. The method detection limits were found to be 0.25, 0.20 and 0.1 ng g À1 for inorganic mercury, ethylmercury and methylmercury, respectively. Method accuracy is traceable to Certified Reference Materials (DOLT-3 and DORM-3) from the National Research Council Canada (NRCC). With the proposed method there is a considerable reduction of the time of sample preparation. Finally, the method was applied for the speciation of mercury in seafood samples purchased from the Brazilian market.

Chemical Product and Process Modeling, 2009

... Vanessa Ribeiro Souza, Federal University of São Carlos ... Algorithm Edson Romano Nucci,Vane... more ... Vanessa Ribeiro Souza, Federal University of São Carlos ... Algorithm Edson Romano Nucci,Vanessa Ribeiro Souza, Rosineide Gomes Silva, Giann Braune Reis, Raquel Lima Camargo Giordano, Roberto Campos Giordano, and Antonio José Gonçalves Cruz Abstract ...

Bioprocess and Biosystems Engineering, 2007

Penicillin G acylase (PGA) is one of the most important enzymes for the pharmaceutical industry. ... more Penicillin G acylase (PGA) is one of the most important enzymes for the pharmaceutical industry. Bacillus megaterium has the advantage of producing extra-cellular PGA. This work compares two neural networks (NNs) architectures for on-line inference of B. megaterium cell mass in an aerated stirred tank bioreactor, during the production of PGA. Nowadays, intelligent computing tools such as artificial NNs and fuzzy logic are commonly applied for state inference and modeling of bioreactors. Combining these two approaches in hybrid, neuro-fuzzy systems, may be advantageous. Our results indicate that a neuro-fuzzy inference system showed a better performance to infer cell concentrations, when compared to multilayer perceptrons networks.

Brazilian Archives of Biology and Technology, 2005

The purpose of this work was to characterize the enzyme penicillin G acylase (PGA) produced by Ba... more The purpose of this work was to characterize the enzyme penicillin G acylase (PGA) produced by Bacillus megaterium. Purification of the enzyme by ultra/diafiltration did not allow the detection of the PGA band by SDS-PAGE electrophoresis due to the high content of remaining proteins. However, using the DNA of the microorganism, it was possible to replicate the genes of the two B. megaterium PGA reported in literature, showing that the enzyme consisted of two sub-units, having 245 and 537 amino acids each and an average molecular mass of 26950 and 59070 Da, respectively. The parameters studied were: 1) the influence of temperature in the 25-600C range, 2) pH in the 5-10 range and 3) substrate concentration, this was tested to obtain results on the Penicillin G hydrolysis reaction rate, using the initial velocities approach. The maximum hydrolysis rate was obtained at 37ºC and pH 8.0. The Michaelis-Menten model fitted well, resulting in estimated Km and Vmax parameters values of 1.83 mM and 0.165*10-3 mmol/min/UI, respectively.

Bioorganic & Medicinal Chemistry Letters, 2005

Five (À)-cubebin derivative compounds, (À)-O-acetyl cubebin (3), (À)-O-benzyl cubebin (4), (À)-O-... more Five (À)-cubebin derivative compounds, (À)-O-acetyl cubebin (3), (À)-O-benzyl cubebin (4), (À)-O-(N,N-dimethylaminoethyl)-cubebin (5), (À)-hinokinin and (À)-6,6 0 -dinitrohinokinin , previously synthesised by our research group, were evaluated on in vitro assay against free amastigote forms of Trypanosoma cruzi, the asogic agent of ChagasÕ disease. It was observed that 6 was the most active compound (IC 50 = 0.7 lM), and that 4 and 5 displayed moderate activity against the parasite, giving IC 50 values of 5.7 and 4.7 lM, respectively. In contrast, it was observed that compound 3 was inactive and that 7 displayed low activity with IC 50 values of ffi1.5 · 10 4 and 95.3 lM, respectively.

Revista Brasileira De Farmacognosia-brazilian Journal of Pharmacognosy, 2008

There are a great number of medicinal plants without any scientific confirmation about their effi... more There are a great number of medicinal plants without any scientific confirmation about their efficacy and safety. This paper is a short review about two medicinal plants, "boldo do chile" (Peumus boldus) and "carqueja" (Baccharis genistelloides). Pharmacological studies have confirmed several popular indications for P. boldus and B. genistelloides, besides have established a relationship between isolated compounds from these extracts and the pharmacological effects observed. On the other hand, toxicological researches have pointed out that P. boldus tea should not be consumed during a long period (potential hepatotoxicity) and by pregnant, especially during the first three months. Moreover, B. genistelloides tea must be prohibited for pregnant because of confirmed abortive action, and for patients using medicines for blood pressure disorders. These studies point out the continuous necessity of more studies about medicinal plants; only with this knowledge it will be possible a safe and efficient use.

Bioorganic & Medicinal Chemistry Letters, 2005

The anti-inflammatory and analgesic effects of three dibenzylbutyrolactone lignans, (À)-hinokinin... more The anti-inflammatory and analgesic effects of three dibenzylbutyrolactone lignans, (À)-hinokinin (2), (À)-6,6 0 -dinitrohinokinin (3), and (À)-6,6 0 -diaminohinokinin (4), obtained by partial synthesis from (À)-cubebin (1), were investigated using different animal models. It was observed that compounds and inhibited the edema formation in the rat paw edema assay at the same level and that all responses were dose dependent. Also, at the dose of 30 mg/kg, compounds 1, 2, 3, and 4 inhibited the edema formation by 53%, 63%, 54%, and 82%, respectively, at the third hour of the experiment. In the acetic acid-induced writhing test in mice, compounds 2 and 4 produced inhibition levels of 97% and 92%, respectively, while 3 displayed lower effect (75%), which was still higher than 1. The assayed compounds neither displayed activity in the cell migration test nor in the hot plate test.