Mandarin essential oil as an antimicrobial in ethanolic fermentation: Effects on Limosilactobacillus fermentum and Saccharomyces cerevisiae.

The antibacterial activity of citrus essential oils (EOs) in the context of combating Limosilactobacillus fermentum, one of the most important bacterial contaminants in the bioethanol production industry, has never been explored previously. Industrial processes usually utilize sulfuric acid for cell treatment to decrease bacterial contamination. However, due to the hazardous nature of sulfuric acid, an alternative to it is highly desirable. Therefore, in the present study, the efficacy of Fremont IAC 543 mandarin EO against a strain of L. fermentum (ATCC® 9338™) was evaluated under proliferative/nonproliferative conditions, in both pure culture and co-culture with an industrial strain of Saccharomyces cerevisiae. The mandarin EO exhibited higher effectiveness against L. fermentum compared to that against S. cerevisiae under nonproliferative conditions (added to water rather than to culture medium). At the concentration of 0·05%, the EO was as effective as the acid solution with pH 2·0 in reducing the count of L. fermentum almost 5 log CFU ml-1 cycles, while the concentration of 0·1% led to the complete loss of bacterial culturability. When L. fermentum was co-cultured with S. cerevisiae, the efficacy of the EO against the bacterial strain was reduced. However, despite this reduced efficacy in co-culture, mandarin EO may be considered effective in combating L. fermentum and could be applied in processes where this bacterium proves to be unfavourable and does not interact with S. cerevisiae.

Serum levels of organochlorine insecticides in humans in Sao Paulo, Brazil.

Residues of organochlorine insecticides were determined by gas chromatograph-electron capture detector in two population groups: one (n = 21) formed by persons living in the neighborhood of a technical HCH (hexachlorocyclohexane) factory and the other (n = 21) constituted of individuals from the general population not occupationally exposed to pesticides. No difference was observed in the serum insecticide levels of the two groups. In the 42 samples, alpha-HCH was observed in 42 (means 1.2 micrograms/L), gamma-HCH was observed in 38 (means 0.4 microgram/L), beta-HCH was observed in 42 (means 7.3 micrograms/L), delta-HCH was observed in 4 (means greater than 0.3 micrograms/L), aldrin was observed in 42 (means 1.4 micrograms/L), p, p'DDE was observed in 42 (means 23.9 micrograms/L), o, p' -DDT was observed in 11 (means less than 0.2 micrograms/L), p,p' -DDD was observed in 32 means 2.1 micrograms/L) and p, p' -DDT was observed in 38 (means 2.1 micrograms/L).

O controle biologico laboratorial da exposicao de trabalhadores e substancias quimicas. A medicina do trabalho e a prevencao da intoxicacao. / Biological laboratorial control of exposure of workers to chemical substances. Occupational medicine and the prevention of poisoning

Neste trabalho os autores discutem a relacao entre Medicina do Trabalho e Toxicologia Ocupacional; informam sobre os meios de pesquisa utilizados a fim de obter o conhecimento toxicologico, para finalmente, discorrerem a respeito do importante tema do uso dos Indicadores Biologicos de Exposicao (IBEs) e dos Limites de Tolerancia Biologicos (LTBs) no controle biologico de exposicao de trabalhadores a substancias quimicas. E apresentada, ainda, uma extensa relacao de IBEs e LTBs propostos

Metemoglobinemia e nitrato nas aguas.

Foram determinados os niveis de metemoglobina em 116 criancas (idade media de 15 meses) do Estado de Sao Paulo (Brasil). Dois grupos foram formados: Grupo 1, por 92 criancas que consumiam agua com teores de nitrato inferiores ao limite de 10 mg N/litro; e Grupo 2, por 24 criancas que bebiam agua de poco com niveis de nitrato superiores ao permitido. A metemoglobinemia media do grupo 1 (0,56%) mostrou-se estatisticamente diferente e inf

Niveis de chumbo e atividade da desidratase do acido gama - aminolevulinico (gama - ALAD) no sangue da populacao da Grande Sao Paulo, Brasil. / Levels of lead and activity of gamma aminolevulinic acid dehydratase (gamma-ALAD) in the blood of the population of Greater Sao Paulo, Brazil

Foram feitas determinacoes de chumbo e atividade da gama-ALAD no sangue de 3 amostras populacionais da Grande Sao Paulo, Brasil. Um grupo (A) de area de escassa exposicao ambiental ao chumbo, um grupo (B) exposto principalmente a fontes moveis de emissao de chumbo e um grupo (C) vizinho a uma industria de recuperacao de chumbo. Cada grupo foi subdividido conforme sexo e habito de fumar. A plumbemia do grupo C (20,5 micro g/100 ml) foi significantemente maior que as dos grupos A (11,2 micro g/100 ml) e B(12,4 micro g/100ml) As correlacoes entre plumbemia e atividade da gama-ALAD, plumbemia e sexo e plumbemia e habito de fumar foram investigadas

Aspecto toxicologico dos hidrocarbonetos aromaticos polinucleares (PAH). / Toxicological aspects of the polynuclear aromatic hydrocarbides (PAH)

Neste artigo de revisao e apresentada a toxicologia dos hidrocarbonetos aromaticos polinucleares (PAH). Destaca-se a sua formacao, sua presenca e seu comportamento no ambiente.Um enfoque especial e dado ao tema carcinogenese, bem como se discute em detalhes a relacao estrutura-atividade. Alem de presentes no ar urbano das principais cidades do mundo, os PAH sao tambem comumente encontrados em ambientes industriais. Atencao e cuidados devem ser voltados ao fato de muitos deles registrarem comprovada acao carcinogenica