Studies on Production of Bacterial Xylanases

Xylanases with hydrolytic activity on xylan, one of the hemicellulosic materials present in plant cell walls, have been identified long back and the applicability of this enzyme is constantly growing. All these applications especially the pulp and paper industries require novel enzymes. There has been lot of documentation on microbial xylanases, however, none meeting all the required characteristics. The characters being sought are: higher production, higher pH and temperature optima, good stabilities under these conditions and finally the low associated cellulase and protease production. The present study analyses various facets of xylanase biotechnology giving emphasis on bacterial xylanases. Fungal xylanases are having problems like low pH values for both enzyme activity and growth. Moreover, the associated production of cellulases at significant levels make fungal xylanases less suitable for application in paper and pulp industries.Bacillus SSP-34 selected from 200 isolates was clearly having xylan catabolizing nature distinct from earlier reports. The stabilities at higher temperatures and pH values along with the optimum conditions for pH and temperature is rendering Bacillus SSP-34 xylanase more suitable than many of the previous reports for application in pulp and paper industries.Bacillus SSP-34 is an alkalophilic thertmotolerant bacteria which under optimal cultural conditions as mentioned earlier, can produce 2.5 times more xylanase than the basal medium.The 0.5% xylan concentration in the medium was found to the best carbon source resulting in 366 IU/ml of xylanase activity. This induction was subjected to catabolite repression by glucose. Xylose was a good inducer for xylanase production. The combination of yeast extract and peptone selected from several nitrogen sources resulted in the highest enzyme production (379+-0.2 IU/ml) at the optimum final concentration of 0.5%. All the cultural and nutritional parameters were compiled and comparative study showed that the modified medium resulted in xylanase activity of 506 IU/ml, 5 folds higher than the basal medium.The novel combination of purification techniques like ultrafiltraton, ammonium sulphate fractionation, DEAE Sepharose anion exchange chromatography, CM Sephadex cation exchange chromatography and Gel permeation chromatography resulted in the purified xylanase having a specific activity of 1723 U/mg protein with 33.3% yield. The enzyme was having a molecular weight of 20-22 kDa. The Km of the purified xylanase was 6.5 mg of oat spelts xylan per ml and Vmax 1233 µ mol/min/mg protein.Bacillus SSP-34 xylanase resulted in the ISO brightness increase from 41.1% to 48.5%. The hydrolytic nature of the xylanase was in the endo-form.Thus the organism Bacillus SSP-34 was having interesting biotechnological and physiological aspects. The SSP-34 xylanase having desired characters seems to be suited for application in paper and pulp industries.

Pionic branches in neutron matter and the problem of pion condensation

The pion spectrum for charged and neutral pions is investigated in pure neutron matter, by letting the pions interact with a neutron Fermi sea in a self-consistent scheme that renormalizes simultaneously the mesons, considered the source of the interaction, and the nucleons. The possibility of obtaining different kinds of pion condensates is investigated with the result that they cannot be reached even for values of the spin-spin correlation parameter, g', far below the range commonly accepted.

Characterization and Pathogenicity of Vibrio cholerae and Vibrio vulnificus from Marine environments

The genus Vibrioof the family Vibrionaceae are Gram negative, oxidasepositive, rod- or curved- rodshaped facultative anaerobes, widespread in marine and estuarine environments. Vibrio species are opportunistic human pathogens responsible for diarrhoeal disease, gastroenteritis, septicaemia and wound infections and are also pathogens of aquatic organisms, causing infections to crustaceans, bivalves and fishes. In the present study, marine environmental samples like seafood and water and sediment samples from aquafarms and mangroves were screened for the presence of Vibrio species. Of the134 isolates obtained from the various samples, 45 were segregated to the genus Vibrio on the basis of phenotypic characterization.like Gram staining, oxidase test, MoF test and salinity tolerance. Partial 16S rDNA sequence analysis was utilized for species level identification of the isolates and the strains were identified as V. cholerae(N=21), V. vulnificus(N=18), V. parahaemolyticus(N=3), V. alginolyticus (N=2) and V. azureus (N=1). The genetic relatedness and variations among the 45 Vibrio isolates were elucidated based on 16S rDNA sequences. Phenotypic characterization of the isolates was based on their response to 12 biochemical tests namely Voges-Proskauers’s (VP test), arginine dihydrolase , tolerance to 3% NaCl test, ONPG test that detects β-galactosidase activity, and tests for utilization of citrate, ornithine, mannitol, arabinose, sucrose, glucose, salicin and cellobiose. The isolates exhibited diverse biochemical patterns, some specific for the species and others indicative of their environmental source.Antibiogram for the isolates was determined subsequent to testing their susceptibility to 12 antibiotics by the disc diffusion method. Varying degrees of resistance to gentamycin (2.22%), ampicillin(62.22%), nalidixic acid (4.44%), vancomycin (86.66), cefixime (17.77%), rifampicin (20%), tetracycline (42.22%) and chloramphenicol (2.22%) was exhibited. All the isolates were susceptible to streptomycin, co-trimoxazole, trimethoprim and azithromycin. Isolates from all the three marine environments exhibited multiple antibiotic resistance, with high MAR index value. The molecular typing methods such as ERIC PCR and BOX PCR revealed intraspecies relatedness and genetic heterogeneity within the environmental isolatesof V. cholerae and V. vulnificus. The 21 strains of V. choleraewere serogroupedas non O1/ non O139 by screening for the presence O1rfb and O139 rfb marker genes by PCR. The virulence/virulence associated genes namely ctxA, ctxB, ace, VPI, hlyA, ompU, rtxA, toxR, zot, nagst, tcpA, nin and nanwere screened in V. cholerae and V. vulnificusstrains.The V. vulnificusstrains were also screened for three species specific genes viz., cps, vvhand viu. In V. cholerae strains, the virulence associated genes like VPI, hlyA, rtxA, ompU and toxR were confirmed by PCR. All the isolates, except for strain BTOS6, harbored at least one or a combination of the tested genes and V. choleraestrain BTPR5 isolated from prawn hosted the highest number of virulence associated genes. Among the V. vulnificusstrains, only 3 virulence genes, VPI, toxR and cps, were confirmed out of the 16 tested and only 7 of the isolates had these genes in one or more combinations. Strain BTPS6 from aquafarm and strain BTVE4 from mangrove samples yielded positive amplification for the three genes. The toxRgene from 9 strains of V. choleraeand 3 strains of V. vulnificus were cloned and sequenced for phylogenetic analysis based on nucleotide and the amino acid sequences. Multiple sequence alignment of the nucleotide sequences and amino acid sequences of the environmental strains of V. choleraerevealed that the toxRgene in the environmental strains are 100% homologous to themselves and to the V. choleraetoxR gene sequence available in the Genbank database. The 3 strains of V. vulnificus displayed high nucleotide and amino acid sequence similarity among themselves and to the sequences of V. cholerae and V. harveyi obtained from the GenBank database, but exhibited only 72% homology to the sequences of its close relative V. vulnificus. Structure prediction of the ToxR protein of Vibrio cholerae strain BTMA5 was by PHYRE2 software. The deduced amino acid sequence showed maximum resemblance with the structure of DNA-binding domain of response regulator2 from Escherichia coli k-12 Template based homology modelling in PHYRE2 successfully modelled the predicted protein and its secondary structure based on protein data bank (PDB) template c3zq7A. The pathogenicity studies were performed using the nematode Caenorhabditiselegansas a model system. The assessment of pathogenicity of environmental strain of V. choleraewas conducted with E. coli strain OP50 as the food source in control plates, environmental V. cholerae strain BTOS6, negative for all tested virulence genes, to check for the suitability of Vibrio sp. as a food source for the nematode;V. cholerae Co 366 ElTor, a clinical pathogenic strain and V. cholerae strain BTPR5 from seafood (Prawn) and positive for the tested virulence genes like VPI, hlyA, ompU,rtxA and toxR. It was found that V. cholerae strain BTOS6 could serve as a food source in place of E. coli strain OP50 but behavioral aberrations like sluggish movement and lawn avoidance and morphological abnormalities like pharyngeal and intestinal distensions and bagging were exhibited by the worms fed on V. cholerae Co 366 ElTor strain and environmental BTPR5 indicating their pathogenicity to the nematode. Assessment of pathogenicity of the environmental strains of V. vulnificus was performed with V. vulnificus strain BTPS6 which tested positive for 3 virulence genes, namely, cps, toxRand VPI, and V. vulnificus strain BTMM7 that did not possess any of the tested virulence genes. A reduction was observed in the life span of worms fed on environmental strain of V. vulnificusBTMM7 rather than on the ordinary laboratory food source, E. coli OP50. Behavioral abnormalities like sluggish movement, lawn avoidance and bagging were also observed in the worms fed with strain BTPS6, but the pharynx and the intestine were intact. The presence of multi drug resistant environmental Vibrio strainsthat constitute a major reservoir of diverse virulence genes are to be dealt with caution as they play a decisive role in pathogenicity and horizontal gene transfer in the marine environments.

Alternativas al curr??culum ordinario para alumnos desmotivados y con desfase en el nivel de competencia curricular

Se presenta memoria final de proyecto educativo que propone el desarrollo de un curr??culum alternativo al ordinario con agrupamientos flexibles y diversificaci??n para segundo y tercero de ESO. Se realiza en el IES La R??a en Huelva. Los objetivos son: plantear al alumnado actividades y experiencias que tengan sentido para ellos; despertar el inter??s por el conocimiento, trabajar habilidades de b??squeda de informaci??n, desarrollo de destrezas; utilizar las nuevas tecnolog??as; aumentar la autoestima; trabajar t??cnicas de prevenci??n y de resoluci??n de conflictos; despertar el inter??s por el medio socio-natural; inter??s por adquirir conocimientos matem??ticos b??sicos; sentimiento de pertenecer a la comunidad aut??noma andaluza.

Form??ndonos para el empleo : educaci??n de personas adultas

El cuaderno incluye una gu??a did??ctica para el profesor

Plan de formación 2003. Comunidad Autónoma de la Región de Murcia.

Plan formativo para los funcionarios públicos de la administración regional que corresponde a la convocatoria general de cursos. El plan se desglosa en tres bloques: cursos de carácter general, dirigidos a colectivos concretos (específicos) y la oferta de los sindicatos.

Acción formativa, conocimientos y habilidades en materia medioambiental.

El código de identificación del curso es 885.- Otros manuales con el mismo título y formato se ocupan de otros módulos de este mismo curso sin proyección educativa

Plan de formación 2004. Comunidad Autónoma de la Región de Murcia.

Plan de formación para empleados públicos de la administración regional murciana para el año 2004. El libro es una especie de catálogo de cursos con una introducción que contiene las disposiciones legales de Hacienda que regulan los mismos. El Plan se divide en tres apartados: una oferta de cursos que es común para todos los funcionarios, otra específica y una última de idiomas, además de cursos de informática para usuarios y de prevención de riesgos laborales. Un total de 127 cursos componen la oferta formativa para el año 2004.

Manual del coordinador : cursos de formación 2004 : Región de Murcia.

En anexo figuran los modelos de anexos y documentos

Paisaje y toponimia : materiales para su aprovechamiento didáctico.

Resumen tomado de los autores

El arte en la escuela: significación del arte en el ciclo superior de la EGB.

Poner en evidencia la situación real de la enseñanza del Arte en los colegios. Recoger opiniones sobre el modelo didáctico usado. Conocer las posibilidades de implantación de un nuevo modelo didáctico. Descubrir las causas que motivan la deficiente iniciativa artística que tienen los centros escolares. Profesores que imparten Ciencias Sociales en la segunda etapa de EGB. Consideraciones sobre las teorías acerca de la enseñanza y la elección de un modelo, análisis de la encuesta efectuada entre los profesores que imparten en la segunda etapa de EGB el área de Ciencias Sociales, comparación de la realidad con su hipótesis del proceso de enseñanza-aprendizaje del Arte. Cuestionarios. El aprendizaje debe ser innovado, desarrollando la participación y la autonomía.

Las enseñanzas artísticas en Aragón.

Se presenta una revisión de la situación de las enseñanzas artísticas superiores en Aragón tras la puesta en vigor de las nuevas leyes educativas en el marco del Espacio Europeo de Educación Superior con las que los estudiantes podrán obtener el título de graduado. Se plantea una nueva metodología de enseñanza adaptada al plan Bolonia: nueva organización de tareas docentes y de investigación, nuevos planes de estudio, nuevas instalaciones... Se hace un repaso a las características principales de los estudios de música, conservación y restauración, danza y arte, las instalaciones con las que cuentan y las actividades que realizan y ofrecen. También se habla de la presencia de las artes como modalidad de bachillerato en Aragón.

Experiencias didácticas en el CDAN : una aproximación al paisaje.

Se habla de las actividades y prácticas llevadas a cabo en el Centro de Arte y Naturaleza de la Fundación Beulas de Huesca. Se explican las acciones llevadas a cabo en el centro y fuera de él para la promoción y conocimiento de dos de sus colecciones: Beaulas-Serrate y arte y naturaleza.

Más allá de la erudición, la anticuaria y el coleccionismo.

Se habla sobre el patrimonio educativo que posee Aragón y se nombra a Rafael Jiménez como persona que impulsó el conocimiento, la difusión y la conservación de estos bienes. También se mencionan y recomiendan algunos libros editados sobre el mismo tema.