Elimination of 4-chlorophenol from Water Solutions Using Commercial Peroxidases

A comparative study of the two most widely used commercial peroxidases (E.C. 1.11.1.7) for removing 4-chlorophenol from aqueous industrial effluents is presented. Both the peroxidases tested, horseradish peroxidase (HRP) and soybean peroxidase (SBP), showed maximal removal efficiency in a neutral pH medium although they maintained more than 70 % of their activity in a pH range of between 6.0 and 8.0. The influence of temperature on the elimination levels was negligible between T = 25 and 40 °C for both enzymes. To minimize the treatment period and enzyme dose, the effect of adding different amounts of a protective agent (polyethylene glycol, PEG) was explored. The final choice of the peroxidase source will depend on the convenience of using such protective agents, SBP being the most suitable when the addition of PEG is not possible or desirable

Functional and structural characterisation of RimL from Bacillus cereus, a new Nα-acetyltransferase of ribosomal proteins that was wrongly assigned as an aminoglycosyltransferase

Enzymes of the GNAT (GCN5-relate N-acetyltransferases) superfamily are important regulators of cell growth and development. They are functionally diverse and share low amino acid sequence identity, making functional annotation difficult. In this study, we report the function and structure of a new ribosomal enzyme, Nα-acetyl transferase from Bacillus cereus (RimLBC), a protein that was previously wrongly annotated as an aminoglycosyltransferase. Firstly, extensive comparative amino acid sequence analyses suggested RimLBC belongs to a cluster of proteins mediating acetylation of the ribosomal protein L7/L12. To assess if this was the case, several well established substrates of aminoglycosyltransferases were screened. The results of these studies did not support an aminoglycoside acetylating function for RimLBC. To gain further insight into RimLBC biological role, a series of studies that included MALDI-TOF, isothermal titration calorimetry, NMR, X-ray protein crystallography, and site-directed mutagenesis confirmed RimLBC affinity for Acetyl-CoA and that the ribosomal protein L7/L12 is a substrate of RimLBC. Last, we advance a mechanistic model of RimLBC mode of recognition of its protein substrates. Taken together, our studies confirmed RimLBC as a new ribosomal Nα-acetyltransferase and provide structural and functional insights into substrate recognition by Nα-acetyltransferases and protein acetylation in bacteria

Role of chaos for the validity of statistical mechanics laws: diffusion and conduction

Several years after the pioneering work by Fermi Pasta and Ulam, fundamental questions about the link between dynamical and statistical properties remain still open in modern statistical mechanics. Particularly controversial is the role of deterministic chaos for the validity and consistency of statistical approaches. This contribution reexamines such a debated issue taking inspiration from the problem of diffusion and heat conduction in deterministic systems. Is microscopic chaos a necessary ingredient to observe such macroscopic phenomena?Comment: Latex, 27 pages, 10 eps-figures. Proceedings of the Conference "FPU 50 years since" Rome 7-8 May 200

Bladder cancer index: cross-cultural adaptation into Spanish and psychometric evaluation

BACKGROUND: The Bladder Cancer Index (BCI) is so far the only instrument applicable across all bladder cancer patients, independent of tumor infiltration or treatment applied. We developed a Spanish version of the BCI, and assessed its acceptability and metric properties. METHODS: For the adaptation into Spanish we used the forward and back-translation method, expert panels, and cognitive debriefing patient interviews. For the assessment of metric properties we used data from 197 bladder cancer patients from a multi-center prospective study. The Spanish BCI and the SF-36 Health Survey were self-administered before and 12 months after treatment. Reliability was estimated by Cronbach's alpha. Construct validity was assessed through the multi-trait multi-method matrix. The magnitude of change was quantified by effect sizes to assess responsiveness. RESULTS: Reliability coefficients ranged 0.75-0.97. The validity analysis confirmed moderate associations between the BCI function and bother subscales for urinary (r = 0.61) and bowel (r = 0.53) domains; conceptual independence among all BCI domains (r ≤ 0.3); and low correlation coefficients with the SF-36 scores, ranging 0.14-0.48. Among patients reporting global improvement at follow-up, pre-post treatment changes were statistically significant for the urinary domain and urinary bother subscale, with effect sizes of 0.38 and 0.53. CONCLUSIONS: The Spanish BCI is well accepted, reliable, valid, responsive, and similar in performance compared to the original instrument. These findings support its use, both in Spanish and international studies, as a valuable and comprehensive tool for assessing quality of life across a wide range of bladder cancer patients

Comunicación corta. Modelización de la dinámica de poblaciones de Phalaris brachystachys bajo diversos escenarios de control herbicida en un clima mediterráneo

The weed Phalaris brachystachys Link (short-spiked canarygrass) severely affects cereal production in regions with a Mediterranean climate. A mathematical model for simulating the population dynamics of this weed was constructed using previously reported brachystachys populations.Phalaris brachystachys Link (alpiste) es una mala hierba que afecta de forma importante a la producción de cereales en regiones de clima mediterráneo. En este trabajo se desarrolló un modelo matemático para simular la dinámica de poblaciones de esta especie. El modelo fue utilizado para describir el comportamiento a largo plazo de las poblaciones en ausencia de prácticas de control y para predecir el efecto de varias estrategias de control basadas en la aplicación de herbicidas al 50%, 75% y 100% de la dosis recomendada en trigo de invierno. En ausencia de control el banco de semilla alcanzó un nivel de equilibrio a una densidad de 21.244 semillas/m cuadrado al sexto año. Bajo aplicación anual de herbicidas al 50%, 75% y 100% de la dosis comercial, la posición de equilibrio de la población se redujo en sólo 5,44%, 12,27% y 23,14% respectivamente. El análisis de sensibilidad indicó que el modelo fue particularmente sensible a la fecundidad, mortalidad del banco de semilla y pérdida de semillas, por tanto, las nuevas estrategias de control deberían estar dirigidas en esta dirección. El modelo desarrollado muestra la dificultad de estabilizar o disminuir la población de alpiste a largo plazo en trigo de invierno. Con el objetivo de obtener un reducción efectiva de las poblaciones de brachystachys se requiere una integración de control por herbicidas con prácticas culturales