Evaluación de la actividad desulfurizadora de aislados nativos de Pseudomonas spp. en presencia de hidrocarburo / Desulfurization activity evaluation of native strains of Pseudomonas spp. in the presence of hydrocarbon

El principal inconveniente en la combustión de los hidrocarburos es la conversión del azufre y el nitrógeno a sus respectivos óxidos, los cuales participan en la formación de lluvia acida y deterioran el medio ambiente e infraestructuras. La remoción de azufre a partir de compuestos órgano-azufrados mediante el uso de microorganismos ha surgido como una alternativa frente al proceso catalítico de hidrodesulfurización (HDS). En el presente trabajo se evaluó la actividad desulfurizadora de veintitrés aislados nativos de Pseudomonas spp. sobre dibenzotiofeno (DBT), usando un sistema de fermentación con igual proporción de fase acuosa y orgánica (n-hexano) en presencia de oleato de etanolamina. Los aislados 02,05 y 06 conservaron su viabilidad en este medio y presentaron una remoción de azufre entre 6,0 y 9,4%, generando los metabolitos DBT-sulfona, DBT-sulfóxido, 2-hidroxibifenilo (2-HBP) y sulfato presentes en la ruta metabólica 4S. Con estos aislados se evaluó la actividad desulfurizadora sobre keroseno y se observó una remoción de azufre entre 19,9 y 62,6% y una disminución del poder calorífico entre 0,45 y 5,55%.

The main difficulty with fossil fuel combustión lies in sulphur and nitrogen becoming converted to their respective oxides, forming part of the acid rain which deteriorates the environment and infrastructure. Removing sulphur from organo-sulfur compounds by using micro-organisms has become an alternative to hydrodesulphurisation (HDS). Twenty-three Pseudomonas spp. native strains' desulphurisation activity on dibenzothiophene (DBT) was evaluated by using a fermentation system having equal proportions of aqueous and organic (n-hexane) phases in the presence of ethanolamine oléate. The 02, 05 and 06 strains maintained their viability in this médium, presenting 6,0% to 9,4% sulphur removal, producing DBT-sulphone, DBT-sulphoxide, 2-hydroxybiphenyl (2-HBP) metabolites and sulphate belonging to the 4S pathway. These native strains' desulphurisation activity was evaluated on kerosene, presenting 19,9% to 62,2% sulphur removal having 0,45% to 5,55% calorific power loss.

Biodegradation of polycyclic aromatic hydrocarbons by soil fungi

Thirteen deuteromycete ligninolytic fungal strains were grown in media containing polycyclic aromatic hydrocarbons (PAHs), for 6 and 10 days. The PAHs were added directly with the inocula or on the third day of cultivation. A selection of the best strains was carried out based on the levels of degradation of the PAHs and also on the ligninolytic activities produced by the fungi. The selected strains were cultivated for 3,6,9,12 and 15 days in the PAHs-containing media. Degradation of PAHs, as measured by reversed-phase HPLSC on a C18 column, varied with each strain as did the ligninolytic enzymes present in the culture supernatants. Highest degradation of naphthalene 69 (per cent) was produced by the strain 984, having Mn-peroxidase activity, followed by strain 870 17 per cente showing lignin peroxidase and laccase activities. The greatest degradation of phenanthrene 12 (per cent) was observed with strain 870 containing Mn-peroxidase and laccase activities. When anthracene was used, the strain 710 produced a good level of degradation 65 per cente.

Influencia de la contaminación atmosférica en la calidad de aire de interiores / Influence of outdoor pollution on indoor air quality

The influence of outdoor pollution on indoor air quality was studied in downtown Santiago (Bandera street). Carbon monoxide (CO), nicotine, particulate matter, respirable fraction (PM5) and total and carcinogenic polyaromatic hydrocarbons (PAHs) were simultaneously monitores indoors and outdoors and indoors in restaurants, offices and other places. The levels of CO changed simultaneously outdoors and indoors (r=0.89) specially during traffic rush hours, demonstrating the importance of outdoor infiltration into the indoor air quality and masking the contribution of other CO indoor sources. The maximun CO concentrations were over 800 percent and over 1000 percent higher indoors and outdoors respectively than the 9 ppm CO National Ambient Air Quality. The PM5 concentrations were very high and showed no significant differences (p>0.05) from indoor to outdoors, or between indoor levels in restaurants, offices and other places. Total ans carcinogenic PAHs levels were also very high, outdoors and indoors, outodoor levels being generally higher than those indoors and no significant; differences (p>0.05) were found for the indoor levels between restaurants, offices and other places. Nicotine levels showed significant differences (p<0.05) between indoor and outdoor levels. In addition, great differences (p<0.05) in indoor levels, were found between offices and restaurants, and offices and other places. Among indoor sources cigarrete smoke seems to be a minor source since nicotine concentrations, bieng 2.3 times higher in restaurants and other places than in offices, do not contribute to enhance significantly PM5 and total and carcinogenic HAPs in the first ones. These results suggest that in downtown Santiago, infiltration might be the main source of indoor pollution. This is supported by 2 evidences: a) coronene, a tracer of vehicle emissions was found in high concentraion indoors and b) in restaurants (in wich PAHs emissions might be higher indoor) a correlation coefficient of 0.987 for the indoor and outdoor concentrations of carcinogenic PAHs was found. Furthermore a survey asking for different symptoms and effects probably related to air pollution was made to people working in Bandera and in a rural area located 40 Km from Santiago. The results showed that excluding smoking as a confounded factor, people working in Bandera showed a significantly greater (p<0.05) risk of ill effects on their health than people working in the rural area

Riscos ocupacionais e cancer de pulmao / Occupational risks and lung cancer

O objetivo deste trabalho é revisar o tópico dos riscos ocupacionais e câncer de pulmäo. Inicialmente, situa-se a importância do câncer de pulmäo no contexto dos cânceres na populaçäo brasileira. Discute-se tendências da incidência da doença em nível mundial, observando-se que os estudos apontam para maior ocorrência nas regiöes mais industrializaas e urbanizadas. Säo discutidas as dificuldades dos estudos epidemiológicos para identificar cancerígenos ocupacionais para o pulmäo, considerando-se aspectos como a multicasualidade envolvida na doença, o período de latência e a intensidade da exposiçäo. É enfocada a associaçäo de determinados fatores causais como tumores pulmonares de tipos histológicos específicos. Discute-se, a seguir, o papel de alguns agentes físicos e químicos ocupacionais, assumidos como mais relevantes, na gênese do câncer de pulmäo: radiaçöes ionizantes, arsênico, asbesto, berílio, cromo, ferro, níquel, clorometil éteres e hidrocarbonetos policíclicos. Säo discutidos ainda determinados processos de trabalho aos quais têm sido associados frequências altas de neoplasia pulmonar. Finalmente, é salientada a importância da prevençäo primária para o controle do câncer de pulmäo de origem ocupacional, tendo em vista o pouco impacto decorrente das prevençöes secundárias e terciárias

Circulación del benzo (a) pireno en las aguas del litoral habanero / Benzo (a) pyrene circulation in Havana's coastal water

Con el fin de determinar la dirección de la circulación de hidrocarburos policíclicos aromáticos (HPA) en nuestras aguas y su posible implicación de un riesgo al ser humano, se realizó un monitoreo de las aguas, sedimentos y algunos organismos bentónicos en dos zonas del litoral habanero (de alta y baja contaminación) para determinar sus niveles de benzo(a) pirenos(BP). Se encontraron niveles de 10 a100 veces más elevados en las aguas del fondo y en los sedimentos, así como en los moluscos, esponjas y gorgonáceas, con respecto a las aguas superficiales, indicando esa dirección en la circulación de los HPA y un posible riesgo carcinogénico para el hombre a través de la cadena alimentaria

Negro de fumo / Fume black

Apresenta informaçöes sobre a descoberta do negro de fumo, processos de fabricaçäo, características e utilizaçäo, efeitos sobre seres humanos e uma proposta de estabelecimento de limite de tolerância para exposiçäo

Inhibition of aminopeptidase activity by aromatic and other cyclic compounds

The effect of 2-naphthylamine, p-nitroaniline, o-phenanthroline, sodium deoxycholate and hydrocortisone succinate on the activity of human urine aminopeptidase, rat kidney methionyl and arginyl aminopeptidase, soybean and Enterolobium contortisiliquum seed aminopeptidase was studied using aminoacyl-2-naphthylamide and L-Leu-p-nitroanilide as substrates. Ki values ranged from 10 microM to 2.7 mM. On the basis of Ki and Km values, and catalytic efficiency for each enzyme, it is clear that the aminopeptidases from human urine and from soybean seed should be assayed with both substrates, whereas L-Leu-p-nitroaniline is a more appropriate substrate for the rat kidney aminopeptidases. Sodium deoxycholate is a better inhibitor than hydrocortisone succinate. Non-competitive inhibition was observed in all cases except for E. contortisiliquum seed aminopeptidase

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