Separation of Scaptotrigona postica Workers into Defined Task Groups by the Chemical Profile on Their Epicuticle Wax Layer

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Genomics-based design of defined growth media for the plant pathogen Xylella fastidiosa

Based on the genetic analysis of the phytopathogen Xylella fastidiosa genome, five media with defined composition were developed and the growth abilities of this fastidious prokaryote were evaluated in liquid media and on solid plates. All media had a common salt composition and included the same amounts of glucose and vitamins but differed in their amino acid content. XDM1 medium contained amino acids threonine, serine, glycine, alanine, aspartic acid and glutamic acid, for which complete degradation pathways occur in X fastidiosa; XDM2 included serine and methionine, amino acids for which biosynthetic enzymes are absent, plus asparagine and glutamine, which are abundant in the xylem sap; XDM3 had the same composition as XDM2 but with asparagine replaced by aspartic acid due to the presence of complete degradation pathway for aspartic acid; XDM4 was a minimal medium with glutamine as a sole nitrogen source; XDM5 had the same composition as XDM4, plus methionine. The liquid and solidified XDM2 and XDM3 media were the most effective for the growth of X. fastidiosa. This work opens the opportunity for the in silico design of bacterial defined media once their genome is sequenced. (C) 2002 Federation of European Microbiological Societies. Published by Elsevier B.V. B.V. All rights reserved.

Atributos físicos e químicos de substratos compostos por biossólidos e casca de arroz carbonizada

O objetivo deste trabalho foi estudar os atributos físicos e químicos de substratos com diferentes doses de biossólido (BIO) e de casca de arroz carbonizada (CAC), com vistas em obter um meio de crescimento adequado para o desenvolvimento de mudas. Desta forma, utilizando biossólido proveniente da SABESP, estação de Franca (SP), estabeleceu-se um ensaio com os seguintes tratamentos (proporções BIO/CAC): 100/0, 90/10, 80/20, 70/30, 60/40, 50/50, 40/60, 30/70, 20/80, 10/90 e 0/100, os quais foram comparados ao substrato comercial Multiplant®. Foram realizadas análises para determinação dos atributos físicos, como: densidade aparente do substrato, macro e microporosidade, porosidade total, capacidade máxima de retenção de água, e dos atributos químicos dos substratos, como: teores totais de macro e micronutrientes, pH, relação C/N e condutividade elétrica. Com a elevação da dose de BIO no substrato houve aumento da densidade e do percentual de microporos e, conseqüentemente, da capacidade de retenção de água. O BIO apresentou teores razoáveis de nutrientes com destaque para N e P, mas baixos teores de K. Não foram detectados teores de metais pesados superiores aos limites estabelecidos pela Legislação Brasileira no biossólido usado. Comparando-se os valores considerados adequados para o desenvolvimento de mudas encontrados na literatura com os obtidos neste trabalho, encaixaram-se na faixa adequada os substratos cujas doses de biossólido variaram de 30 a 60 %. Nenhum substrato testado, incluindo o do tratamento com substrato comercial, apresentou valores ideais em todas as propriedades estudadas.

Iron phthalocyanine in non-aqueous medium forming layer-by-layer films: growth mechanism, molecular architecture and applications

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chemical and microbiological evaluation of the internal surfaces of aluminum tubes both unlined and lined with epoxi resin by means of the stereoscope and scanning electron microscope

A superfície interna das bisnagas fabricadas com alumínio não revestido e revestido com resina epóxi, utilizadas para acondicionar cremes, pomadas, géis, etc., foram avaliadas quimicamente e por métodos microbiológicos correlacionados com a aderência de microrganismos. A prova da porosidade e da resistência à remoção da resina foi observada por meio do microscópio eletrônico de varredura (Topcon FM300) e estereoscópio Leica (MZ12) acoplado a Sistema de Digitalização de Imagens. Para avaliar a ação dos microrganismos foram utilizados corpos-de-prova esterilizados (discos de 10mm de diâmetro), imersos em caldo Mueller Hinton (Difco) e colocados em tubos de polipropileno com tampa de rosca (Corning). Foram inoculados tubos com meio de cultura para cada uma das suspensões bacterianas (10(9)UFC/mL) de Streptococcus agalactiae, Staphylococcus aureus, Acinetobacter lwoffii e Candida albicans, incubados a 37°C, sob agitação constante durante 12 dias. O meio de cultura era trocado a cada 3 dias. Após esse período, os corpos-de prova foram removidos, processados e observados em microscópio eletrônico de varredura JEOL-JSM (T330A). A observação por meio do microscopio eletrônico de varredura mostrou a aderência e a formação de biofilme sobre a superfície de alumínio não revestido e revestido com resina epóxi.

A theoretical analysis on the intramolecular proton transfer of alpha-alanine in an aqueous medium

Intramolecular proton transfer from oxygen to nitrogen atoms in the alpha-alanine amino acid has been studied by ab initio methods at the HF/6-31G*, HF/6-31 ++ G** and MP2/6-31 ++ G** levels of calculation including the solvent effects by means of self-consistent reaction field theory. An analysis of the results based on the natural bond orbital charges shows that the transition structure presents an imbalance in the sense that the charge shift lags behind the proton transfer and that the bond formation is always in advance with respect to the bond cleavage. All calculation levels show that the barrier height associated with the conformational change on alpha-alanine is larger than the proton transfer process. (C) 1998 Elsevier B.V. B.V. All rights reserved.

Flow-injection spectrophotometric determination of novalgin in phrmaceuticals using micellar medium

A sensitive flow-injection (FI) procedure with spectrophotometric detection in a micellar medium is proposed for the determination of novalgin. The method is based on the instantaneous formation of a red-orange product (lambda(max) = 510 nm) after the reaction between novalgin and p-dimethylaminocinnamaldehyde (p-DAC) in a dilute acid medium. The sensitivity of this reaction was increased by a factor of 5.6 in the presence of sodium dodecyl sulfate (SDS). Experimental design methodologies were used to optimize the chemical and FI variables. The calibration curve was linear in the range of 1.45 x 10(-6) to 2.90 x 10(-5) mol L-1 with an excellent correlation coefficient (r = 0.9999). The detection limit was 1.31 x 10(-7) mol L-1 (n = 20, RSD = 2.0%). No interferences were observed from the common excipients. The results obtained by the proposed method were favorably compared with those given by the iodometric reference method at 95% confidence level.

Electrochemical evidence of sulfinic acid derivative as an intermediate in the reduction of aromatic sulfonyl chloride in an aprotic medium

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

4-amine-2-mercaptopyrimidine modified silica gel applied in Cd(II) and Pb(II) extraction from an aqueous medium

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Attachment of 2,2-bipyridine onto a silica gel for application as a sequestering agent for copper, cadmium and lead ions from an aqueous medium

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Natural killer activity in a medium-term multi-organ bioassay for carcinogenesis

Natural killer (NK) cell activity was evaluated after the initiation and promotion steps in a medium-term multi-organ bioassay for carcinogenesis. NK cell activity was assessed in vitro by Cr-51 release assay at the 4th and 30th weeks of the experiment. Male Wistar rats were sequentially initiated with N-diethylnitrosamine (DEN i.p.), N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN drinking water), N-methyl-N-nitrosourea (MNU i.p.), dihydroxy-di-N-propylnitrosamine (DHPN drinking water) and N,N'-dimethylhydrazine (DMH s.c.) at subcarcinogenic doses for 4 weeks (DMBDD initiation). One group was evaluated at the 4th week and the other was maintained without any further treatment until the 30th week. Two initiated groups were exposed through the diet to 2-acetylaminofluorene (2-AAF) or phenobarbital (PB), from the 6th until the 30th week, Five additional groups were studied to evaluate the effects of each initiator on NK activity. All groups submitted to initiation only, initiation plus promotion, or promotion only, developed significantly more preneoplastic lesions than the untreated control group. The main target organs for tumor development in the initiated animals n ere the liver and the colon, irrespective of treatment with 2-AAF or PB. NK cell activity was not affected bal exposure to genotoxic carcinogens after initiation, at the 4th week. Treatments only with PB or 2-AAF did not change NK cell activity, However, decreased NK cell activity was registered in the group only initiated with DMBDD and in the group given DMBDD+2-AAF. This late depression of NK cell activity at the 30th week could be related to the production of suppressing molecules by the tumor cells.

Chemically induced immunotoxicity in a medium-term multiorgan bioassay for carcinogenesis with Wistar rats

A variety of chemicals can adversely affect the immune system and influence tumor development. The modifying potential of chemical carcinogens on the lymphoid organs and cytokine production of rats submitted to a medium-term initiation-promotion bioassay for carcinogenesis was investigated. Male Wistar rats were sequentially initiated with N-nitrosodiethylamine (DEN), N-methyl-N-nitrosourea (MNU), N-butyl-N-(4hydroxybutyl)nitrosamine (BBN), dihydroxy-di-n-propylnitrosamine (DHPN), and 1,2-dimethylhydrazine (DMH) during 4 weeks. Two initiated groups received phenobarbital (PB) or 2-acetyl amino fluorene (2-AAF) for 25 weeks and two noninitiated groups received only PB or 2-AAF. A nontreated group was used as control. Lymphohematopoietic organs, liver, kidneys, lung, intestines, and Zymbal's gland were removed for histological analysis. Interleukin (IL)-2, IL-12, interferon gamma (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), IL-10, and transforming growth factor betal (TGF-beta1) levels were determined by ELISA in spleen cell culture supernatants. At the fourth week, exposure to the initiating carcinogens resulted in cell depletion of the thymus, spleen and bone marrow, and impairment of IL-2, IL-12, and IFN-gamma production. However, at the 30th week, no important alterations were observed both in lymphoid organs and cytokine production in the different groups. The results indicate that the initiating carcinogens used in the present protocol exert toxic effects on the lymphoid organs and affect the production of cytokines at the initiation step of carcinogenesis. This early and reversible depression of the immune surveillance may contribute to the survival of initiated cells facilitating the development of future neoplasia. (C) 2003 Elsevier B.V. All rights reserved.

Lymphoproliferative response and T lymphocyte subsets in a medium-term multi-organ bioassay for carcinogenesis in Wistar rats

The lymphoproliferative response and T lymphocyte subsets were evaluated at different stages of carcinogenesis in male Wistar, rats sequentially initiated with N-diethylnitrosamine (DEN), N-butyl-N-4(hydroxybutyl)nitrosamine (BBN), N-methyl-N-nitrosourea (MNU), dihydroxy-di-N-propylnitrosamine (DHPN) and N,N'-dimethylhydrazine (DMH) (DMBDD initiation). One group was evaluated at the 4th week and other initiated group at the 30th week. Two initiated groups were also exposed through diet to 7-acetylaminofluorene (2-AAF) or phenobarbital (PB), from the 6th until the 30th week. Two groups received only 2-AAF or PB until the 30th week. Five groups were studied to evaluate the effects of each initiator. The lymphoproliferative response was induced in vitro by concanavalin A and the percentage of T lymphocyte subsets was determined by flow cytometry, All groups submitted to initiation only, initiation plus promotion, or promotion only, developed significantly more preneoplastic: lesions than the untreated control group. The main target organs for tumor development were the liver, colon, urinary bladder, kidneys and Zymbal glands, mainly in the group treated with DMBDD + 2-AAF, There were no alterations of the lymphoproliferative response and of the T lymphocyte subsets percentage in the DMBDD-treated group at the 4th and 30th weeks. At the 30th week, the T lymphocyte subsets percentage was also not affected in the initiated groups after treatments with 2-AAF or PB. The lymphoproliferative response, however, was decreased in the DMBDD + 2-AAF group and in the groups treated only with 2-AAF or PB, the present results indicate that the initiating chemicals used in the DMBDD initiation protocol do not exert any influence on the immune system. The alteration of lymphoproliferative response induced at the advanced stage of carcinogenesis without alteration of T lymphocyte subsets may indicate that the influence of 2-AAF and PB on the immune system is functional and not toxic. (C) 2000 Elsevier B.V. Ireland Ltd. All rights reserved.

Absence of carcinogenic and anticarcinogenic effects of annatto in the rat liver medium-term assay

Annatto (Bixa orellana L.) is a natural food colorant extensively used in many processed foods, especially dairy products. The lower cost of production and the low toxicity, make annatto a very attractive and convenient pigment in substitution to the many synthetic colorants. In the present study we investigate the carcinogenic and anticarcinogenic effects of dietary annatto in Wistar rat liver using the preneoplastic glutathione S-transferase (GST-P) foci and DNA damage biomarkers. Annatto, containing 5% bixin, was administered in the diet at concentrations of 20, 200, and 1000 ppm (0.07; 0.80 and 4.23 bixin/kg body wt/day, respectively), continuously during 2 weeks before, or 8 weeks after DEN treatment (200 mg/kg body wt, i.p.), to evaluate its effect on the liver-carcinogenesis medium-term bioassay. The comet assay was used to investigate the modifying potential of annatto on DEN (20 mg/kg body wt)-induced DNA damage. The results showed that annatto was neither genotoxic nor carcinogenic at the highest concentration tested (1000 ppm). No protective effects were also observed in both GST-P foci development and comet assays. In conclusion, in such experimental conditions, annatto shows no hepatocarcinogenic effect or modifying potential against DEN-induced DNA damage and preneoplastic foci in the rat liver. (C) 2004 Elsevier Ltd. All rights reserved.