Influence of agitation and aeration in xanthan production by Xanthomonas campestris pv pruni strain 101 / Influencia de la agitación y la aireación en la producción de xantano por Xanthomonas campestris pv. pruni cepa 101

Production, viscosity, and chemical composition of xanthan synthesized by bacterium Xanthomonas campestris pv pruni strain 101 were evaluated in bioreactor systems. During the process, the volumetric oxygen mass transfer coefficient (kLa) and the biomass were determined and the pH was monitored. The cultures were grown in a 3 l bioreactor, with aeration and agitation varying as follows: conditions (A) 300 rpm, 3 vvm and (B) 200 rpm, 2 vvm, at 28 °C. Our results showed that gum production was dependent on kLa, with a maximum yield of 8.15 g/l at 300 rpm, 3 vvm, 54 h of fermentation, kLa 21.4/h, while biomass was not affected. All aqueous solutions of 3% (w/v) xanthans synthesized showed a pseudoplastic behavior. The highest viscosity was reached under the strongest aeration/agitation conditions. All xanthan samples contained glucose, mannose, rhamnose, and glucuronic acid as their main components. The highest agitation and aeration rates used under condition A (300 rpm and 3 vvm) favorably influenced the yield and viscosity of the xanthan produced by bacterium X. campestris pv pruni 101 at different fermentation times.

Se evaluó la producción, viscosidad y composición química del xantano sintetizado por la bacteria Xanthomonas campestris pv. pruni cepa 101 en un fermentador. Durante el proceso se controló el pH y se determinaron el coeficiente de transferencia de masa de oxígeno (kLa) y la producción de masa celular seca. Los cultivos se realizaron en un fermentador de 3 l variando la aireación y la agitación, en las siguientes condiciones: (A) 300 rpm, 3 vvm y (B) 200 rpm, 2 vvm; a 28 °C. Nuestros resultados mostraron que la producción de goma fue dependiente del kLa, con un rendimiento máximo de 8,15 g/l a 300 rpm y 3 vvm a las 54 h de fermentación, kLa de 21,4/h, mientras que la producción de biomasa no se afectó. Todas las soluciones acuosas de xantano al 3% (m/v) sintetizadas presentaron comportamiento pseudoplástico. La mayor viscosidad se alcanzó en la condición de aireación/agitación más intensa. Todas las muestras de xantano contenían glucosa, manosa, ramnosa y ácido glucurónico como constituyentes principales. La mayor tasa de agitación y aireación utilizada en la condición A (300 rpm y 3 vvm) influyó favorablemente en el rendimiento y la viscosidad del xantano producido por la bacteria X. campestris pv. pruni 101 a diferentes tiempos de fermentación.

Frequency of Hepatitis "C" in Buner, NWFP

To assess the frequency of hepatitis C in District Buner. Descriptive study. This study was conducted on outdoor patients in Medical OPD of District Headquarter [DHQ] Hospital, Daggar from January 1998 to December 2002. A total of 16,400 patients of age between [15-70 years], who attended the outpatients department of Medical Unit at DHQ, Daggar with non-specific symptoms of dyspepsia, heart burn, bloating, generalized body aches and pain in right hypochondrium were screened for anti-HCV anti-bodies by 3rd generation ELISA. PCR and abdominal ultrasound was also done. Standard treatment was also given. Risk factors were evaluated. Population of district was regionwise divided into sectors A-D and then into subsectors. Out of 16,400 patients, 751 were found positive for anti-HCV antibodies [4.57%].The mean age of the patients was 37 years. The youngest was 15 years while the oldest was 65 years. The frequency of hepatitis C was higher among the male, 409/751 [54.46%] as compared to female, 342/751[45.53%]. Hundred percent [751/751] had history of injections, 52/751 [6.92%] had major surgery, 8/751 [1.06%] had blood transfusion, 73/751 [9.72%] had dental procedure, 3/751 [0.39%] had tattooing and 332/751 [44.20%] had shaving by community barbers. The highest prevalence of hepatitis C was found in sector A1 [9.7%] and the lowest in sector D3 [0.5%]. Hepatitis C is a common health problem in District Buner, and needs proper attention to alleviate the suffering of the people. It is essential to assess the magnitude of the problem, which will help us in understanding the dynamic of its transmission for control and prevention

High biodegradetion levels of 4, 5, 6-trichloroguaiacol by "Bacillus" sp. isolates from pupl mill effluent

An aerobic Gram positive spore-forming bacterium was isolated drom cellulose pulp mill effluent. This microorganism, identified as "Bacillus" sp. and named IS13, was able to rapdly degrade the organic chlorinateed compound 4, 5, 6-trichloroguaiacol (4, 5, 6-TCG) from a culture containing 50 mg/l, wich corresponds to about 3,0E4 times the concentration found in the organic chlorinated compound 4, 5, 6-TCG decreasing, the lack of by-products had shown by such analysis lead to verify the possibility of either adsorption of absorption of 4, 5, 6-TCG by the cells, instead of real biodegradation. There were no traces of 4, 5, 6-TCG. Plasmid isolation was attempted by using different protocols. The best results werw reached by CTAB method, but no plamid DNA was found in "Bacillus"sp. IS13. The results suggest that genes located at the bacterial chromossome might mediate the high decrease of 4, 5, 6-TCG. The importance of this work is that, in being a natural ocurring microorganism, "Bacillus" sp. IS13, can be used as inoculum in plant effluents to best organochlorinated compounds biodegradation.

Incidencia de angiossarcoma hepatico em relacao a exposicao ao PVC em nosso meio. / Incidence of hepatic angiosarcoma associated with PVC exposition in our enveronment

A partir da decada de 70, comecou-se a estabelecer uma relacao causal entre a incidencia de angiossarcoma de figado e a exposicao cronica de trabalhadores ao cloreto de polivinila. O presente trabalho teve por objetivo a realizacao de estudo sobre eventuais casos registrados em nosso meio, estudo este que consistiu na exploracao de registros medicos industriais e hospitalares que se constitui em pesquisa inedita dada a inexistencia de qualquer referencia bibliografica sobre o problema no Brasil. Devido a uma serie de dificuldades com as quais se defrontaram os autores, foi-lhes impossivel a execucao de uma estatistica eficiente e concreta, fatos estes que analisam no conteudo do texto