Ferrous iron biooxidation in a flooded packed-bed bioreactor at extreme conditions of iron concentration and acidity

The utility of ferrous iron biooxidation is to regenerate Fe(III) at required rates and conditions in specific hydrometallurgical contexts, such as metal extraction from ores/concentrates and mining and electronic waste. In these applications, considerable kinetics improvements can be achieved by increasing [Fe(III)], but pH must be decreased to avoid precipitation of this oxidant. Information about continuous biooxidation operation is limited to [Fe] pH > 1, therefore, it is interesting to test wider ranges for these parameters. A 1L flooded packed-bed bioreactor (30 cm in height), inoculated with Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans, was operated 60 days in continuous mode without interruptions at [Fe] up to 57 g/L and pH up to 0.44. Total Fe(II) conversion was achieved when operating at [Fe] = 57 g/L and pH = 1.2. The maximum biooxidation rate reached was 3.5 g/L·h for [Fe] = 40 g/L and 1 h of hydraulic retention time. Biooxidation rate decreases by 32 % when pH decreases from 1.2 to 0.44. Nevertheless, the biofilm remained stable at this low pH and steady state was achieved. When comparing the relative decreases in biooxidation rate and oxygen solubility, the drop of efficiency can be explained by aeration limitations and salting out effect

Physics and Mathematics in the Engineering Curriculum: Correlation with Applied Subjects

This paper presents a study in which the relationship between basic subjects (Mathematics and Physics) and applied engineering subjects (related to Machinery, Electrical Engineering, Topography and Buildings) in higher engineering education curricula is evaluated. The analysis has been conducted using the academic records of 206 students for five years. Furthermore, 34 surveys and personal interviews were conducted to analyze the connections between the contents taught in each subject and to identify student perceptions of the correlation with other subjects or disciplines. At the same time, the content of the different subjects have been analyzed to verify the relationship among the disciplines.Aproper coordination among subjects will allow students to relate and interconnect topics of different subjects, even with the ones learnt in previous courses, while also helping to reduce dropout rates and student failures in successfully accomplishing the different courses

Mortandades en masa producidas por cianobacterias tóxicas en el Parque Nacional de Doñana

La proliferación de cianobacterias productoras de toxinas en el agua es conocida mundialmente como posible causa de mortandades masivas en seres humanos, animales domésticos y fauna salvaje. El presente trabajo estudia la muerte repentina de 5.500 aves y 20 toneladas de peces en el Parque Natural de Doñana, mediante el análisis físico-químico y tóxico del agua, la detección de toxinas en cadáveres y bioensayos en ratón.Este trabajo ha sido financiado por los proyectos CGL2004-02701/HID del Ministerio de Educación y Ciencia, CGL2005-01938/BOS, Parques Nacionales 093/2003, Comunidad de Madrid P05-RNM-00935 y beca DOÑANA-2005

Seguimiento de la infección por el virus de maedivisna en una explotación de ganado ovino

La enfermedad de Maedi-Visna está producida por el retrovirus homónimo (MVV), muy similar en todas sus características al que produce la artritis-encefalitis-caprina (CAEV). Ambas enfermedades son de distribución mundial y se caracterizan por cuadros clínicos parecidos, afectando a distintos sistemas, aunque algunos se pre-sentan con más frecuencia en ovejas y otros en cabras. Una de las observaciones más habituales es la presencia de virus en mamas, y aunque puede cursar sin alteraciones clínicas, en ocasiones puede desencadenar mamitis clínicas o subclínicas. En el presente estudio se analizó la infección por MVV en una explotación de ganado ovino de la Co-munidad de Castilla La Mancha, realizando cinco muestreos de sangre y de leche en los mismos 50 animales, aproximadamente cada dos meses y medio. Los objetivos eran comparar métodos serológicos (ELISA) y virológicos (PCR), estudiar la evolución de la infección y de la respuesta inmune humoral a lo largo del tiempo, sus repercusiones so-bre la producción láctea, y analizar posibles diferencias entre aislados víricos de sangre y leche dentro del mismo animal, a lo largo del tiempo y en diferentes animales. La prevalencia inicial fue del 64% y la final del 76%, por lo que la infección se había transmitido eficazmente en la población estudiada. Sin embargo, los resultados habidos por PCR (empleando una técnica que amplifica un fragmento muy conservado en pol) y por ELISA (utilizando ELITEST comercial) fueron muy dispares, observán-dose una gran falta de concordancia. También se observó falta de concordancia entre los resultados obtenidos de leche y de sangre para cada animal y cada toma. De hecho, los valores kappa globales y desglosados por tomas fueron muy débiles (0,10-0,23). Esto puede deberse a que a) los animales tarden mucho tiempo, incluso años en seroconver-tir; b) la técnica ELISA empleada no detecte todas las inmunoglobulinas en leche (o no detecte bien); o c) el pequeño número de células infectadas presentes en las muestras de leche en diferentes momentos del estudio. Una interpretación “beneficiosa” de la falta de concordancia entre los resultados serológicos y los de PCR podría ser que tras la infección vírica se produzca una fuerte respuesta inmune humoral que limite la detección del virus. Sin embargo, este no fue el caso porque en varias ocasiones se detectó ADN proviral tanto en animales que nunca seroconvirtieron (indicando baja inmunogenicidad del virus), como en otros que sí pre-sentaron anticuerpos frente a MVV. Además, la detección de ADN proviral mediante PCR no fue constante en un animal dado a lo largo del tiempo. Todas estas observacio-nes sugieren que el virus pueda estar experimentando mutaciones tras ser detectado ini-cialmente por el sistema inmune, que le permitan escapar de él. Intentamos responder a esta posibilidad secuenciando los fragmentos amplificados por PCR. Sin embargo, dado que habíamos elegido una región conservada del genoma vírico, y al bajo número de se-cuencias que hemos concluido, no podemos confirmar la hipótesis por el momento. Da-do que la respuesta inmune humoral no es eficaz cabe pensar que la infección esté más o menos controlada por la respuesta inmune celular. Finalmente, a lo largo de nuestro estudio se observó la posible relación entre la mamitis subclínica y la infección por MVV en animales PCR positivos pero ELISA ne-gativos. Este hecho reforzaría la teoría de que se produce una respuesta celular tan fuer-te y temprana que posiblemente destruiría las células infectadas con MVV presentes en la glándula mamaria. De este modo aumentarían el número de células en leche, favore-ciendo la detección de la mamitis subclínica por el test de mamitis de California. // FOLLOW-UP OF THE INFECTION BY MAEDI-VISNA VIRUS IN A SHEEP FARM AUTHORS: Nieves Perdigones, Esperanza Gómez-Lucía, Ana Doménech Maedi-Visna disease is produced by a retrovirus, MVV, very similar in all its characteristics to the one that produces caprine-arthritis encephalitis (CAEV). Both dis-eases are worldwide and are characterised by similar clinical signs, affecting different systems, though some are more frequent in sheep and others in goats. One of the most frequent findings is the presence of virus in the mammary glands, and though it may oc-cur without clinical manifestations, some other times it may spark clinical or subclinical mastitis. In the present study, the infection by MVV was evaluated in a sheep farm in the Comunidad de Castilla La Mancha, by sampling a group of 50 animals five times throughout a year, approximately every 2.5 months. The aims of the study were to com-pare serological (ELISA) with virological (PCR) methods, study the evolution of the in-fection and of the humoral immune response during this period, its effects over milk yield, and analyse the possible differences between viral isolates in blood and milk in the same animal, throughout time, and in different animals. Initial prevalence was 64% and at final prevalence 76%; it was inferred that the infection had been efficiently transmitted in the population under study. However, re-sults obtained by PCR (using a technique that amplifies a very conserved fragment in the pol region) and by ELISA (using the commercial ELITEST) were very variable, with a high degree of discordance. Results obtained from milk and blood for each ani-mal and in each sampling were also discordant. In fact, the global and individual kappa values were very low (0.10-0.23). Possible explanations are a) that animals may take long, even years, to seroconvert; b) the ELISA technique used did not detect (or de-tected poorly) all the immunoglobulins in milk; or c) the low number of infected cells present in milk samples in the different moments of the study. A “beneficial” interpretation of the discordance between serological and PCR results may be that the immune response is very efficient and that after the viral infec-tion a strong humoral response initiates which restricts viral detection. However, this was not the case, as in several occasions proviral DNA was detected in animals that never seroconverted (suggesting a low viral immunogenicity), and in others that did present antibodies against MVV. In addition, proviral DNA detection by PCR was not constant in a given animal throughout time. All these results suggest that the virus might be experiencing mutations after its initial detection by the immune system, allowing the virus to escape. We attempted to answer this possibility by sequencing the fragments amplified by PCR. However, as we chose a conserved region in the viral genome, and we concluded few sequences, at the present moment we cannot confirm this hypothesis. As the humoral immune response appears not to be efficient it is reasonable to think that the infection is more or less controlled by the cell mediated immunity. Finally, in our study we observed a possible relationship between subclinical mastitis and MVV infection in PCR positive but ELISA negative animals. This fact would reinforce the theory that there is such a strong and early cellular reaction that it would possibly destroy the cells infected by MVV present in the mammary gland. This way, the number of cells in milk would increase, allowing the detection of subclinical mastitis by California mastitis test

Estudio de genes de susceptibilidad no-"HLA" implicados en artritis reumatoide en población española

La artritis reumatoide (AR) es una enfermedad auto-inmune inflamatoria crónica que afecta aproximadamente al 1% de la población europea y norteamericana. Aunque la causa última de la enfermedad todavía no ha sido determinada, se sabe que existen factores genéticos y ambientales implicados en el desarrollo y la severidad de la enfermedad. nuestro trabajo contribuye al conocimiento de la base genetica de la AR en población espanola, ya que propone la asociacion de nuevos factores geneticos de susceptibilidad y valida otros. Ademas, nuestro trabajo demuestra la existencia de factores geneticos de susceptibilidad que contribuyen especificamente al desarrollo de AR en ciertos subgrupos de pacientes, lo que apoya la idea de que se deberia revisar la actual clasificacion de la AR.[ABSTRACT]Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease affecting aproximately 1% of European and Western populations. Although its aetiology remains elusive, it is known that genetic and environmental factors trigger disease development and severity. Our work contributes to unveil the genetic basis of RA in the Spanish population by assessing novel genetic risk factors and validating others. In addition, we show based on the evidence of our research that some genetic factors contribute specifically to RA development in certain RA subgroups of patients, supporting the idea that a comprehensive RA classification should be sought

Case Report: Paroxysmal nocturnal hemoglobinuria in a woman heterozygous for G6PD A- [v2; ref status: indexed, http://f1000r.es/4kn]

We describe a case of paroxysmal nocturnal hemoglobinuria (PNH) in a woman who is heterozygous for the glucose-6-phosphate dehydrogenase A-   (G6PDA-) allele. PNH is associated with one or more clones of cells that lack complement inhibition due to loss of function somatic mutations in the PIGA gene.  PIGA encodes the enzyme phosphatidylinositol glycan anchor biosynthesis, class A, which catalyses the first step of glycosylphosphatidylinisotol (GPI)  anchor synthesis. Two GPI anchored red cell surface antigens regulate complement lysis. G6PD catalyses the first step of the pentose phosphate pathway and enzyme variants, frequent in some populations have been selected because they confer resistance to malaria, are associated with hemolysis in the presence of oxidizing agents including several drugs. The patient had suffered a hemolytic attack after taking co-trimoxazole, a drug that precipitates hemolysis in G6PD deficient individuals. Since both G6PD and PIGA are X-linked we hypothesized that the PIGA mutation was on the X-chromosome carrying the G6PDA- allele. Investigations showed that in fact the PIGA mutation was on the X-chromosome carrying the normal G6PD B allele. We speculate that complement activation on G6PD A- red cells exposed to Bactrim might have triggered complement activation inducing the lysis of G6PD B PNH Type II red blood cells or that the patient may have had a PNH clone expressing G6PDA- at the time of the hemolytic episode

Genomic landscapes of canine splenic angiosarcoma (hemangiosarcoma) contain extensive heterogeneity within and between patients.

Cancer genomic heterogeneity presents significant challenges for understanding oncogenic processes and for cancer's clinical management. Variation in driver mutation frequency between patients with the same tumor type as well as within an individual patients' cancer can shape the use of mutations as diagnostic, prognostic, and predictive biomarkers. We have characterized genomic heterogeneity between and within canine splenic hemangiosarcoma (HSA), a common naturally occurring cancer in pet dogs that is similar to human angiosarcoma (AS). HSA is a clinically, physiologically, and genomically complex canine cancer that may serve as a valuable model for understanding the origin and clinical impact of cancer heterogeneity. We conducted a prospective collection of 52 splenic masses from 43 dogs (27 HSA, 15 benign masses, and 1 stromal sarcoma) presenting for emergency care with hemoperitoneum secondary to a ruptured splenic mass. Multi-platform genomic analysis included matched tumor/normal targeted sequencing panel and exome sequencing. We found candidate somatic cancer driver mutations in 14/27 (52%) HSAs. Among recurrent candidate driver mutations, TP53 was most commonly mutated (30%) followed by PIK3CA (15%), AKT1 (11%), and CDKN2AIP (11%). We also identified significant intratumoral genomic heterogeneity, consistent with a branched evolution model, through multi-region exome sequencing of three distinct tumor regions from selected primary splenic tumors. These data provide new perspectives on the genomic landscape of this veterinary cancer and suggest a cross-species value for using HSA in pet dogs as a naturally occurring model of intratumoral heterogeneity

Somatic inactivating PTPRJ mutations and dysregulated pathways identified in canine malignant melanoma by integrated comparative genomic analysis

Canine malignant melanoma, a significant cause of mortality in domestic dogs, is a powerful comparative model for human melanoma, but little is known about its genetic etiology. We mapped the genomic landscape of canine melanoma through multi-platform analysis of 37 tumors (31 mucosal, 3 acral, 2 cutaneous, and 1 uveal) and 17 matching constitutional samples including long- and short-insert whole genome sequencing, RNA sequencing, array comparative genomic hybridization, single nucleotide polymorphism array, and targeted Sanger sequencing analyses. We identified novel predominantly truncating mutations in the putative tumor suppressor gene PTPRJ in 19% of cases. No BRAF mutations were detected, but activating RAS mutations (24% of cases) occurred in conserved hotspots in all cutaneous and acral and 13% of mucosal subtypes. MDM2 amplifications (24%) and TP53 mutations (19%) were mutually exclusive. Additional low-frequency recurrent alterations were observed amidst low point mutation rates, an absence of ultraviolet light mutational signatures, and an abundance of copy number and structural alterations. Mutations that modulate cell proliferation and cell cycle control were common and highlight therapeutic axes such as MEK and MDM2 inhibition. This mutational landscape resembles that seen in BRAF wild-type and sun-shielded human melanoma subtypes. Overall, these data inform biological comparisons between canine and human melanoma while suggesting actionable targets in both species