Cloning and characterisation of four catA genes located on the chromosome and large plasmid of Pseudomonas putida ND6

Background: Although the functional redundancy of catechol 1,2-dioxygenase (C12O) genes has been reported in several microorganisms, limited enzymes were characterised, let alone the advantage of the coexistence of the multiple copies of C12O genes. Results: In this study, four novel C12O genes, designated catA, catAI, catAII and catAIII, in the naphthalene-degrading strain Pseudomonas putida ND6, were cloned and characterised. Phylogenetic analysis of their deduced amino acid sequences revealed that the four C12O isozymes each formed independent subtrees, together with homologues from other organisms. All four enzymes exhibited maximum activity at pH 7.4 and higher activity in alkaline than in acidic conditions. Furthermore, CatA, CatAI and CatAIII were maximally active at a temperature of 45°C, whereas a higher optimum temperature was observed for CatAII at a temperature of 50°C. CatAI exhibited superior temperature stability compared with the other three C12O isozymes, and kinetic analysis indicated similar enzyme activities for CatA, CatAI and CatAII, whereas that of CatAIII was lower. Significantly, among metal ions tested, only Cu2+ substantially inhibited the activity of these C12O isozymes, thus indicating that they have potential to facilitate bioremediation in environments polluted with aromatics in the presence of metals. Moreover, gene expression analysis at the mRNA level and determination of enzyme activity clearly indicated that the redundancy of the catA genes has increased the levels of C12O. Conclusion: The results clearly imply that the redundancy of catA genes increases the available amount of C12O in P. putida ND6, which would be beneficial for survival in challenging environments.

Simultaneous biodegradation of phenol and cyanide present in coke-oven effluent using immobilized Pseudomonas putida and Pseudomonas stutzeri

ABSTRACT Discharge of coke-oven wastewater to the environment may cause severe contamination to it and also threaten the flora and fauna, including human beings. Hence before dumping it is necessary to treat this dangerous effluent in order to minimize the damage to the environment. Conventional technologies have inherent drawbacks however, biological treatment is an advantageous alternative method. In the present study, bacteria were isolated from the soil collected from the sites contaminated by coke-oven effluent rich in phenol and cyanide. Nucleotides sequence alignment and phylogenetic analysis showed the identity of the selected phenol and cyanide degrading isolates NAUN-16 and NAUN-1B as Pseudomonas putida and Pseudomonas stutzeri, respectively. These two isolates tolerated phenol up to 1800 mg L-1 and cyanide up to 340 mg L-1 concentrations. The isolates were immobilized on activated charcoal, saw dust and fly ash. The effluent was passed through the column packed with immobilized cells with a flow rate of 5 mL min-1. The isolates showed degradation of phenol up to 80.5% and cyanide up to 80.6% and also had the ability to reduce biological oxygen demand, chemical oxygen demand and lower the pH of effluent from alkaline to near neutral. The study suggests the utilization of such potential bacterial strains in treating industrial effluent containing phenol and cyanide, before being thrown in any ecosystem.

GPo1 alkB gene expression for improvement of the degradation of diesel oil by a bacterial consortium

To facilitate the biodegradation of diesel oil, an oil biodegradation bacterial consortium was constructed. The alkane hydroxylase (alkB) gene of Pseudomonas putida GPo1 was constructed in a pCom8 expression vector, and the pCom8-GPo1 alkB plasmid was transformed into Escherichia coli DH5α. The AlkB protein was expressed by diesel oil induction and detected through SDS-polyacrylamide gel electrophoresis. The culture of the recombinant (pCom8-GPo1 alkB/E. coli DH5α) with the oil biodegradation bacterial consortium increased the degradation ratio of diesel oil at 24 h from 31% to 50%, and the facilitation rates were increased as the proportion of pCom8-GPo1 alkB/E. coli DH5α to the consortium increased. The results suggested that the expression of the GPo1 gene in E. coli DH5α could enhance the function of diesel oil degradation by the bacterial consortium.

"El hecho de que sean más mujeres, no garantiza nada": feminización y experiencias de las mujeres en la ginecobstetricia en México / "The fact that there are more women doesn't guarantee anything": The feminization of obstetrics and gynecology and the experiences of female medical professionals in Mexico

En el marco de la creciente feminización de la profesión médica en México, el artículo indaga sobre las características de este proceso para el caso de la ginecobstetricia. Considerando la feminización como un proceso de cambio, que se analiza cuantitativa y cualitativamente, el artículo se detiene en especial en las experiencias de las mujeres ginecobstetras, experiencias que se dan en el seno de una especialidad que, desde sus orígenes, funcionó como un dispositivo de control del cuerpo de las mujeres. Basado en una investigación etnográfica, el artículo combina fuentes estadísticas, de archivo y de observación de campo. El material que surge de las entrevistas muestra las experiencias y tensiones que viven las ginecobstetras en este contexto.

In the framework of an increasing feminization of the medical profession in Mexico, this article explores the characteristics of this process in the obstetrics and gynecology specialty. Understanding feminization as a process of change to be analyzed both quantitatively and qualitatively, the article focuses special attention on the experiences of female obstetrician-gynecologists within a medical specialty that has since its origins functioned as a mechanism of control over women's bodies. Based on ethnographic research, the article combines statistical and archival sources and field observation. The interviews reveal the experiences and tensions women obstetrician-gynecologists encounter in this context.

Further characterization of o-nitrobenzaldehyde degrading bacterium Pseudomonas sp: ONBA-17 and deduction on its metabolic pathway

A previously reported o-nitrobenzaldehyde (ONBA) degrading bacterium Pseudomonas sp. ONBA-17 was further identified and characterized. Based on results of DNA base composition and DNA-DNA hybridization, the strain was identified as P. putida. Its degradation effect enhanced with increase of inoculum amount and no lag phase was observed. Higher removal rate was achieved under shaking conditions. All tested ONBA with different initial concentrations could be completely degraded within 5 d. In addition, degradative enzyme(s) involved was confirmed as intra-cellular distributed and constitutively expressed. Effects of different compounds on relative activity of degradative enzyme(s) within cell-free extract were also evaluated. Finally, 2-nitrobenzoic acid and 2, 3-dihydroxybenzoic acid were detected as metabolites of ONBA degradation by P. putida ONBA-17, and relevant metabolic pathway was preliminary proposed. This study might help with future research in better understanding of nitroaromatics biodegradation.

Temporomandibular Disorders in a Sample Population of the Brazilian Northeast

Temporomandibular disorder (TMD) is a common condition. This study is part of a research group and it investigated the prevalence of TMD and myofascial pain and its association with gender, age and socioeconomic class. The sample comprised 100 subjects, aged 15 to 70, users of the Family Health Units' services, in the city of Recife, PE, Brazil. The TMD degree was evaluated using the Research Diagnostic Criteria for TMD and socioeconomic class by the Economic Classification Criteria Brazil. Categorical variables were analyzed by chi-square test for proportions and Fisher's exact test for 2x2 tables, and binary logistic analysis to track the relationship between the independent and dependent variables. According to the results, 42% of the subjects had TMD and 14% myofascial pain. No statistically significant association could be found between TMD and gender or socioeconomic class, but it was found to have statistically significant association with age, and myofascial pain was associated with socioeconomic class. Considering that the results of the present study should be confirmed by further studies and the fact that this was a pilot study, the prevalence must be analyzed with caution.

Disfunção temporomandibular (DTM) é uma condição comum. Este estudo é parte de um grupo de pesquisa e investigou a prevalência de DTM e dor miofascial e suas associações com sexo, idade e classe socioeconômica. A amostra foi composta por 100 indivíduos, com idades entre 15 e 70 anos, usuários das Unidades de Saúde da Família, na cidade de Recife, PE. O grau de DTM foi avaliado usando os Critérios de Diagnósticos Científicos em DTM, e classe socioeconômica com o Critério de Classificação Econômica Brasil. As variáveis categóricas foram analisadas pelo teste do qui-quadrado para proporções e teste exato de Fisher para tabelas 2x2, e a análise logística binária para traçar a relação entre as variáveis independentes e dependentes. De acordo com os resultados, 42% dos indivíduos tinham DTM e 14% dor miofascial. Não houve associação estatisticamente significativa entre DTM e sexo ou classe socioeconômica, mas houve associação estatisticamente significativa com a idade e a dor miofascial foi associada com a classe socioeconômica. Considerando-se que os resultados do presente estudo devam ser confirmados em outros estudos e por causa de sua natureza piloto, a prevalência deve ser analisada com cautela.

Marine Pseudomonas putida: a potential source of antimicrobial substances against antibiotic-resistant bacteria

Bacteria isolated from marine sponges found off the coast of Rio de Janeiro, Brazil, were screened for the production of antimicrobial substances. We report a new Pseudomonas putida strain (designated P. putida Mm3) isolated from the sponge Mycale microsigmatosa that produces a powerful antimicrobial substance active against multidrug-resistant bacteria. P. putida Mm3 was identified on the basis of 16S rRNA gene sequencing and phenotypic tests. Molecular typing for Mm3 was performed by RAPD-PCR and comparison of the results to other Pseudomonas strains. Our results contribute to the search for new antimicrobial agents, an important strategy for developing alternative therapies to treat infections caused by multidrug-resistant bacteria.

[Cloning and expression of SOX [dsz A, B, C] operon in E.coli strain DH5alpha and comparison its desulfurization activity with Pesudomonas aeroginosa EGSOX, Pesudomonas putida EGSOX and E.coli cc118 lamda p ir]

The combustion of sulfur-containing fossil fuels is a source of environmental pollution. During previous decades, desulfurization of fossil fuels has been considered as a costeffective and alternative friendly environmental approach. DBT has been widely used as a model compound to screen microorganisms ability for desulfurization. There are several reports on the isolation of DBT-desulfurizing bacteria. In this respect, Rhodococus erythropolis IGTS8 has an desulfurization operon [dsz A, B, C], which can convert DBT, as a source of sulfur, to 2HBP via the 4s pathway. In this study, the [dsz A, B, C] operon was cloned into the PVLT31 plasmid and then transformed into the E.coli DH5 alpha. Plasmid purification was performed using mini prep and analysied by PCR technique and restriction endonuclease. Desulfurization activity was measured and compared between the recombinant and Rhodococus erythropolis IGTS8, Pesudomonas aeroginosa EGSOX, Pesudomonas putida EGSOX and E.coli cc118 lambda pir by Gibb's assay and HPLC. Maximum 2HBP production was detected in Pesudomonas aeroginosa EGSOX and E.coli DH5alpha, respectively. Specific activity for desulfurization of DBT is boosted by increasing the copy number of [dsz A, B, C] operon and sulfur repression can be alleviated by promoter replacement