Degradation of textile dyes by cyanobacteria

Abstract Dyes are recalcitrant compounds that resist conventional biological treatments. The degradation of three textile dyes (Indigo, RBBR and Sulphur Black), and the dye-containing liquid effluent and solid waste from the Municipal Treatment Station, Americana, São Paulo, Brazil, by the cyanobacteria Anabaena flos-aquae UTCC64, Phormidium autumnale UTEX1580 and Synechococcus sp. PCC7942 was evaluated. The dye degradation efficiency of the cyanobacteria was compared with anaerobic and anaerobic-aerobic systems in terms of discolouration and toxicity evaluations. The discoloration was evaluated by absorption spectroscopy. Toxicity was measured using the organisms Hydra attenuata, the alga Selenastrum capricornutum and lettuce seeds. The three cyanobacteria showed the potential to remediate textile effluent by removing the colour and reducing the toxicity. However, the growth of cyanobacteria on sludge was slow and discoloration was not efficient. The cyanobacteria P. autumnale UTEX1580 was the only strain that completely degraded the indigo dye. An evaluation of the mutagenicity potential was performed by use of the micronucleus assay using Allium sp. No mutagenicity was observed after the treatment. Two metabolites were produced during the degradation, anthranilic acid and isatin, but toxicity did not increase after the treatment. The cyanobacteria showed the ability to degrade the dyes present in a textile effluent; therefore, they can be used in a tertiary treatment of effluents with recalcitrant compounds.

Antimitotic and antimutagenic action of the Hymenaea stigonocarpa bark on dividing cells / Ação antimitótica e antimutagênica do ritidoma de Hymenaea stigonocarpa Mart ex Hayne na divisão celular

Abstract The objective of this study was to evaluate the action of Hymenaea stigonocarpa bark hydroalcoholic extract against a mutagenic compound using A. cepa meristematic root cells as a test system. The treatment groups were: Negative Control (NC) – distilled water; Positive Control (PC) – paracetamol at a concentration of 0.008 mg/mL, Jatoba Control (JC) – aqueous fraction jatobá-do-cerrado at 0.5 or 1.0 or 1.5 mg/mL, and Simultaneous Treatment (ST) - jatobá-do-cerrado aqueous fraction at a concentration of 0.5 or 1.0 or 1.5 mg/mL associated with paracetamol solution at a concentration of 0.008 mg/mL. All groups were analyzed at 24 and 48 h. Five onion bulbs (five replications) were used for each treatment group. The root tips were fixed in Carnoy and slides prepared by the crush technique. Cells were analyzed throughout the cell cycle, totaling 5,000 for each treatment group at each exposure time. Mitotic indices were subjected to statistical analysis using the chi-square test (p<0.05). From the results it was found that the ST group, at the three concentrations, significantly potentiated the antiproliferative effect of the test system cells when compared to PC, NC and TJ at the three concentrations. Furthermore, the three ST concentrations significantly reduced the number of cell aberrations when compared to the number of aberrant cells obtained for the PC, demonstrating antimutagenic action on the A. cepa test system cells.

Resumo O objetivo do presente trabalho foi avaliar a ação do extrato hidroalcólico do ritidoma de Hymenaea stigonocarpa frente a um composto mutagênico, utilizando como sistema teste as células meristemáticas de raízes de A. cepa. Os grupos tratamentos avaliados foram: Controle Negativo (CN) – água destilada; Controle Positivo (CP) – paracetamol na concentração de 0,008 mg/mL, Controle Jatobá (CJ) – fração aquosa de jatobá-do-cerrado na concentração de 0,5 ou 1,0 ou 1,5 mg/mL, e Tratamento Simultâneo (TS) – fração aquosa de jatobá-do-cerrado na concentração de 0,5 ou 1,0 ou 1,5 mg/mL associada a solução de paracetamol na concentração de 0,008 mg/mL. Todos os grupos foram analisados nos tempos de 24 e 48 h. Para cada grupo tratamento cinco bulbos de cebolas (cinco repetições) foram utilizados. As radículas foram fixadas em Carnoy e as lâminas preparadas pela técnica de esmagamento. Analisaram-se células em todo ciclo celular, totalizando 5.000 para cada grupo tratamento em cada tempo de exposição. Os índices mitóticos obtidos foram submetidos à análise estatística do Qui-quadrado (p<0,05). A partir dos resultados verificou-se que o grupo TS, nas três concentrações, potencializou o efeito antiproliferativo significativo as células do sistema teste quando comparado ao CP, CN e TJ nas três concentrações. Ainda, o TS nas três concentrações reduziu de forma significativa o número de aberrações celulares quando comparado com o número de células aberrantes obtidas para o CP, demonstrando ação antimutagênica as células do sistema teste A. cepa.

Double mutation of Saccharomyces cerevisiae for enhanced β-D-fructofuranosidase fructohydrolase productivity and application of growth kinetics for parametric significance analysis

Abstract The kinetics of an extracellular β-D-fructofuranosidase fructohydrolase production by Saccharomyces cerevisiae in a chemically defined medium, i.e., sucrose peptone agar yeast extract at pH 6, was investigated. The wild-type was treated with a chemical mutagen, methyl methane sulfonate. Among the six mutants isolated, methyl methane sulfonate-V was found to be a better enzyme producing strain (52 ± 2.4a U/mL). The maximum production (74 ± 3.1a U/mL) was accomplished after at 48 h (68 ± 2.7a mg/mL protein). The mutants were stabilized at low levels of 5-fluoro-cytocine and the viable ones were further processed for optimization of cultural conditions and nutritional requirements. The sucrose concentration, incubation period and pH were optimized to be 30 g/L, 28 °C, and 6.5, respectively. The methyl methane sulfonate-V exhibited an improvement of over 10 folds in enzyme production when 5 g/L ammonium sulfate was used as a nitrogen source. Thin layer chromatography and high-performance liquid chromatography analysis illustrated the optimal enzyme activity supported by the higher rate of hydrolysis of sucrose into monosaccharides, particularly α-D-glucose and β-D-fructose. The values for Qp (2 ± 0.12c U/mL/h) and Yp/s (4 ± 1.24b U/g) of the mutant were considerably increased in comparison with other yeast strains (both isolates and viable mutants). The mutant could be exploited for enzyme production over a wider temperature range (26–34 °C), with significantly high enzyme activity (LSD 0.048, HS) at the optimal temperature.

The improvement of competitive saprophytic capabilities of Trichoderma species through the use of chemical mutagens

Abstract The antagonistic potential of Trichoderma strains was assayed by studying the effect of their culture filtrate on the radial growth of Sclerotium rolfsii, the causal agent of chickpea collar rot. Trichoderma harzianum-1432 (42.2%) and Trichoderma atroviride (40.3%) were found to be strong antagonists. To enhance their antagonistic potential, mutagenesis of these two selected strains was performed. Two mutants, Th-m1 and T. atroviride m1, were found to be more effective than their parent strains. The enzymatic activities of the selected parent and mutant strains were assayed, and although both mutants were found to have enhanced enzymatic activities compared to their respective parent strains, Th-m1 possessed the maximum cellulase (5.69 U/mL) and β-1,3-glucanase activity (61.9 U/mL). Th-m1 also showed high competitive saprophytic ability (CSA) among all of the selected parent and mutant strains, and during field experiments, Th-m1 was found to successfully possess enhanced disease control (82.9%).

O discurso do excesso sexual como marca da brasilidade: revisitando o pensamento social brasileiro das décadas de 1920 e 1930 / The discourse of sexual excess as a hallmark of Brazilianness: revisiting Brazilian social thinking in the 1920s and 1930s

O objetivo deste trabalho é analisar o discurso do excesso sexual produzido pelo pensamento social brasileiro das décadas de 1920 e 1930 na sua interlocução com o discurso médico da época. De inspiração foucaultiana, o texto inscreve-se no campo da história dos saberes e está subsidiado por documentos sociológicos e médicos do período de referência. No quadro da recodificação vintecentista sobre o imaginário da brasilidade, o tema do excesso sexual foi revisitado pelo pensamento sociológico local, forjando-o ora como um perturbador do projeto civilizatório nacional, ora como um traço que deveria ser positivado por ter sido a condição de possibilidade da hibridização cultural de suas matrizes identitárias.

The objective of this article is to analyze the discourse of sexual excess produced by Brazilian social thinking in the 1920s and 1930s and its dialog with the medical discourse at the time. Inspired by Foucault, it is within the field of the history of knowledge and is supported by sociology and medical documents from the period in question.Within the framework of the twentieth century re-codification of the imagery of Brazilianness, the topic of sexual excess was revisited by local thinkers in the field of sociology and seen either as disturbing the national civilizing project, or as a trait that should be seen in a positive light because it permitted the cultural hybridization of its sources of identity.

Kinetic characterization of glucose aerodehydrogenase from Aspergillus niger EMS-150-F after optimizing the dose of mutagen for enhanced production of enzyme

In the present study enhanced production of glucose aerodehydrogenase from Aspergillus niger has been achieved after optimizing the dose of chemical mutagen ethyl methane sulfonate (EMS) that has not been reported earlier. Different doses of mutagen were applied and a strain was developed basing upon the best production. The selected strain Aspergillus niger EMS-150-F was optimized for nutrient requirements in order to produce enzyme through fermentation and the results showed the best yield at 2% corn steep liquor (CSL), 36 hours fermentation time, pH 5, 30°C temperature, 0.3% KH2PO4, 0.3% urea and 0.06% CaCO3. The enzyme was then purified and resulted in 57.88 fold purification with 52.12% recovery. On kinetic characterization, the enzyme showed optimum activity at pH 6 and temperature 30°C. The Michaelis-Menton constants (Km, Vmax, Kcat and Kcat/Km) were 20 mM, 45.87 U mL-1, 1118.81 s-1 and 55.94 s-1 mM-1, respectively. The enzyme was found to be thermaly stable and the enthalpy and free energy showed an increase with increase in temperature and ΔS* was highly negative proving the enzyme from A. niger EMS-150-F resistant to temperature and showing a very little disorderliness.

Enhancement of wanlongmycin production by nitrogen ion beam implantation / Mejora de la producción de wanlongmycin por implantación de haces iónicos de nitrógeno

In an attempt to obtain an industrial strain with higher yield of wanlongmycin, the wild strain Streptomyces griseovariabilis GAAS2507 was mutated by a novel mutagen, nitrogen ion beam with energy of 20 kilo electron volts (KeV) and dose ranging from 7.80 x 10(14) to 2.86 x 10(15) ions/cm². One mutant strain WN939 was obtained. Its yield of wanlongmycin reached 271.24 µg/mL, which was 82.10 percent higher than that of the wild strain. The mutant strain WN939 was relatively stable for the production of wanlongmycin through six successive transfers of cultures and a repeat fermentation in a 30 L fermentor. In addition, the mutant strains were investigated and divided into five types by their colony phenotypes and production of wanlongmycin. Among them, three types mutant strains exhibited positive mutation, while the other two types mutant strains exhibited negative mutation.

Detection of polycyclic aromatic hydrocarbon exposure from automobile exhaust fumes using urinary 1-hydroxypyrene level as an index.

Polycyclic aromatic hydrocarbons (PAHs) are hydrocarbon compounds which originate from incomplete combustion. In humans, PAHs are bioactivated to reactive metabolites which can bind covalently to DNA and subsequently initiate mutation and carcinogenesis. The measurement of PAHs exposure may be used as an index to classify a cancer risk group. The purpose of the present study was to measure the level of urinary 1-hydroxypyrene, a metabolite of PAHs, in subjects exposed to automobile exhaust fumes compared to non-exposed subjects. A urine sample was collected from each individual subject after the end of a working day and quantitated for 1-hydroxypyrene and creatinine by HPLC and spectrophotometric method, respectively. The results showed that average urinary 1-hydroxypyrene level in exposed subjects was significantly higher than non-exposed subjects (mean +/- SD of 0.0035 +/- 0.0032 and 0.0011 +/- 0.0010 micromol/l, respectively; P = 0.000). Average urinary creatinine level in exposed subjects was also significantly higher than non-exposed subjects (mean +/- SD of 0.01 +/- 0.005 and 0.008 +/- 0.006 mol/l, respectively; P = 0.040). The ratio of urinary 1-hydroxypyrene/mol creatinine level, of the exposed subjects was significantly higher than that of the non-exposed subjects (mean +/- SD of 0.37 +/- 0.28 and 0.19 +/- 0.22 micromol/mol creatinine, respectively; P = 0.002). CONCLUSION: Automobile exhaust fume exposed subjects have a higher risk to be exposed to PAHs than the non-exposed subjects. Urinary 1-hydroxypyrene level can be used as an index for an exposure of PAHs which have originated from automobile exhaust fumes and other sources as well.

Teste de AMES como uma ferramenta para detecçäo de citotoxidade e mutagenicidade causadas por metais pesados e radicais livres / Ames test as a tool for detection of citotoxicity and mutagenicity caused by heavy metals and the free radicals

Considerando a interaçäo complexa entre diferentes compostos químicos e metais, a influência desses fenômenos sobre o meio ambiente e consequentemente, sobre o ser humano, esta revisäo tem como objetivo mostrar que o Teste de Ames ainda hoje, é uma ferramenta importante na detecçäo de mutágenos

Production of hydroquinol from p-benzoquinone using yeast.

Reduction of p-benzoquinone to hydroquinol has been studied using Saccharomyces cerevisae and S.uvarum. Maximum conversion of p-Benzoquinone (p-BQ) to Hydroquinol (HQ) at a substrate concentration of 6%. S. cerevisae was found to be better than S. uvarum. No further conversion did take place after 60 hr. Optical innoculam density was found to be 5-6% (v/v). The pH optima was observed at pH value 5.50. No significant improvement could be observed by doping acetone, which solubilizes p-BQ, to the medium.