Vectorial signalling mechanism required for cell-cell communication during sporulation in Bacillus subtilis

Spore formation in Bacillus subtilis takes place in a sporangium consisting of two chambers, the forespore and the mother cell, which are linked by pathways of cellcell communication. One pathway, which couples the proteolytic activation of the mother cell transcription factor sE to the action of a forespore synthesized signal molecule, SpoIIR, has remained enigmatic. Signalling by SpoIIR requires the protein to be exported to the intermembrane space between forespore and mother cell, where it will interact with and activate the integral membrane protease SpoIIGA. Here we show that SpoIIR signal activity as well as the cleavage of its N-terminal extension is strictly dependent on the prespore fatty acid biosynthetic machinery. We also report that a conserved threonine residue (T27) in SpoIIR is required for processing, suggesting that signalling of SpoIIR is dependent on fatty acid synthesis probably because of acylation of T27. In addition, SpoIIR localization in the forespore septal membrane depends on the presence of SpoIIGA. The orchestration of sE activation in the intercellular space by an acylated signal protein provides a new paradigm to ensure local transmission of a weak signal across the bilayer to control cellcell communication during development.

Integration of processes induced air flotation and photo-Fenton for treatment of residual waters contaminated with xylene

Produced water in oil fields is one of the main sources of wastewater generated in the industry. It contains several organic compounds, such as benzene, toluene, ethyl benzene and xylene (BTEX), whose disposal is regulated by law. The aim of this study is to investigate a treatment of produced water integrating two processes, i.e., induced air flotation (IAF) and photo-Fenton. The experiments were conducted in a column flotation and annular lamp reactor for flotation and photodegradation steps, respectively. The first order kinetic constant of IAF for the wastewater studied was determined to be 0.1765 min(-1) for the surfactant EO 7. Degradation efficiencies of organic loading were assessed using factorial planning. Statistical data analysis shows that H2O2 concentration is a determining factor in process efficiency. Degradations above 90% were reached in all cases after 90 min of reaction, attaining 100% mineralization in the optimized concentrations of Fenton reagents. Process integration was adequate with 100% organic load removal in 20 min. The results of the integration of the IAF with the photo-Fenton allowed to meet the effluent limits established by Brazilian legislation for disposal. (C) 2011 Elsevier B.V. All rights reserved.

Dominance hierarchies and social status ascent opportunity: Anticipatory behavioral and physiological adjustments in a Neotropical cichlid fish

In this work we characterized the social hierarchy of non-reproductive individuals of Cichlasoma dimerus (Heckel, 1840). independently for both sexes, and its relationship to the opportunity for social status ascent. Female and male individuals who were located on the top rank of the social hierarchy, ascended in social status when the opportunity arose, therefore indicating that dominance is directly correlated with social ascent likelihood. Dominance was positively correlated with size in males but not in females, suggesting for the latter a relationship with intrinsic features such as aggressiveness or personality rather than to body and/or ovarian size. Physiological and morphometrical variables related to reproduction, stress and body color were measured in non-reproductive fish and correlated with dominance and social ascent likelihood. Dominance was negatively correlated with plasma cortisol levels for both sexes. No correlation with dominance was found for androgen plasma levels (testosterone and 11-ketotestosterone). No correlation was detected between dominance and the selected morphological and physiological variables measured in females, suggesting no reproductive inhibition in this sex at a physiological level and that all females seem to be ready for reproduction. In contrast, social hierarchy of non-reproductive males was found to be positively correlated with follicle stimulating hormone (FSH) pituitary content levels and gonadosomatic indexes. This suggests an adaptive mechanism of non reproductive males, adjusting their reproductive investment in relation to their likelihood for social status ascent, as perceived by their position in the social hierarchy. This likelihood is translated into a physiological signal through plasma cortisol levels that inhibit gonad investment through pituitary inhibition of FSH, representing an anticipatory response to the opportunity for social status ascent. (C) 2012 Elsevier Inc. All rights reserved.

Crystal structures of Leptospira interrogans FAD-containing ferredoxin-NADP+ reductase and its complex with NADP+

Abstract Background Ferredoxin-NADP(H) reductases (FNRs) are flavoenzymes that catalyze the electron transfer between NADP(H) and the proteins ferredoxin or flavodoxin. A number of structural features distinguish plant and bacterial FNRs, one of which is the mode of the cofactor FAD binding. Leptospira interrogans is a spirochaete parasitic bacterium capable of infecting humans and mammals in general. Leptospira interrogans FNR (LepFNR) displays low sequence identity with plant (34% with Zea mays) and bacterial (31% with Escherichia coli) FNRs. However, LepFNR contains all consensus sequences that define the plastidic class FNRs. Results The crystal structures of the FAD-containing LepFNR and the complex of the enzyme with NADP+, were solved and compared to known FNRs. The comparison reveals significant structural similarities of the enzyme with the plastidic type FNRs and differences with the bacterial enzymes. Our small angle X-ray scattering experiments show that LepFNR is a monomeric enzyme. Moreover, our biochemical data demonstrate that the LepFNR has an enzymatic activity similar to those reported for the plastidic enzymes and that is significantly different from bacterial flavoenzymes, which display lower turnover rates. Conclusion LepFNR is the first plastidic type FNR found in bacteria and, despite of its low sequence similarity with plastidic FNRs still displays high catalytic turnover rates. The typical structural and biochemical characteristics of plant FNRs unveiled for LepFNR support a notion of a putative lateral gene transfer which presumably offers Leptospira interrogans evolutionary advantages. The wealth of structural information about LepFNR provides a molecular basis for advanced drugs developments against leptospirosis.

PTTG expression in different experimental and human prolactinomas in relation to dopaminergic control of lactotropes

Abstract Background Pituitary tumor transforming gene (pttg) is a novel oncogene that is expressed at higher level in most of the tumors analyzed to date compared to normal tissues. Nevertheless, its expression in prolactinomas and its relation with the pituitary dopamine receptor 2 (D2R) are not well defined. We sought to determine the pituitary level of pttg in three different experimental models of prolactinomas with altered dopaminergic control of the pituitary: the dopaminergic D2R knockout female mouse, the estrogen-treated rat, and the senescent female rat. These three models shared the characteristics of increased pituitary weight, hyperprolactinemia, lactotrope hyperplasia and reduced or absent dopaminergic action at the pituitary level. We also studied samples from human macroprolactinomas, which were characterized as responsive or resistant to dopamine agonist therapy. Results When compared to female wild-type mice, pituitaries from female D2R knockout mice had decreased PTTG concentration, while no difference in pttg mRNA level was found. In senescent rats no difference in pituitary PTTG protein expression was found when compared to young rats. But, in young female rats treated with a synthetic estrogen (Diethylstylbestrol, 20 mg) PTTG protein expression was enhanced (P = 0.029). Therefore, in the three experimental models of prolactinomas, pituitary size was increased and there was hyperprolactinemia, but PTTG levels followed different patterns. Patients with macroprolactinomas were divided in those in which dopaminergic therapy normalized or failed to normalize prolactin levels (responsive and resistant, respectively). When pituitary pttg mRNA level was analyzed in these macroprolactinomas, no differences were found. We next analyzed estrogen action at the pituitary by measuring pituitary estrogen receptor α levels. The D2R knockout female mice have low estrogen levels and in accordance, pituitary estrogen receptors were increased (P = 0.047). On the other hand, in senescent rats estrogen levels were slightly though not significantly higher, and estrogen receptors were similar between groups. The estrogen-treated rats had high pharmacological levels of the synthetic estrogen, and estrogen receptors were markedly lower than in controls (P < 0.0001). Finally, in patients with dopamine resistant or responsive prolactinomas no significant differences in estrogen receptor α levels were found. Therefore, pituitary PTTG was increased only if estrogen action was increased, which correlated with a decrease in pituitary estrogen receptor level. Conclusion We conclude that PTTG does not correlate with prolactin levels or tumor size in animal models of prolactinoma, and its pituitary content is not related to a decrease in dopaminergic control of the lactotrope, but may be influenced by estrogen action at the pituitary level. Therefore it is increased only in prolactinomas generated by estrogen treatment, and not in prolactinomas arising from deficient dopamine control, or in dopamine resistant compared with dopamine responsive human prolactinomas. These results are important in the search for reliable prognostic indicators for patients with pituitary adenomas which will make tumor-specific therapy possible, and help to elucidate the poorly understood phenomenon of pituitary tumorigenesis.

Iheringichthys syi (Siluriformes: Pimelodidae), a new pimelodid species from upper Paraná basin, Brazil

We describe a new species of pimelodid catfish of the genus Iheringichthys from the upper Paraná basin, Brazil. Iheringichthys syi n. sp. is distinguished by the comparatively fine serration along the anterior margin of the pectoral-fin spine, an adpressed dorsal-fin remote from the adipose-fin origin, a large eye (23.2-31.2% of head length), narrow interorbital (16.2-23.0% of head length), long snout (42.0-51.0% of head length), long postorbital length (30.6-34.0% of head length), low adipose fin (4.8-7.8% of standard length), eye diameter 97.0-140.0% of interorbital length, and body with numerous, small dots irregularly scattered on flanks, especially marked on anterior half of flank.

Biodiversidad y turismo para un desarrollo sostenible

Organizan el ciclo de conferencias el Centro de Formación de la Cooperación Española en Cartagena de Indias con la colaboración de Cátedra UNESCO de Planificación Turística y Desarrollo Sostenible de la Universidad de Las Palmas de Gran Canaria entre otros

Gestión ambiental de las zonas costeras

Organizan el ciclo de conferencias el Centro de Formación de la Cooperación Española en Cartagena de Indias con la colaboración de Cátedra UNESCO de Planificación Turística y Desarrollo Sostenible de la Universidad de Las Palmas de Gran Canaria -Tides-

Pasado y presente de las relaciones comerciales entre las Islas Canarias y África

[ES] El presente trabajo es una aproximación centrada en la evolución del comercio canario-africano entre 2001 y 2011, así como en los principales valores obtenidos por las exportaciones e importaciones, incidiendo especialmente en la localización geográfica de los países proveedores y los mercados de destino de las producciones más relevantes. Todo ello se ha hecho sin perder de vista la perspectiva peculiar del Archipiélago con una economía escasamente industrializada en el contexto español, y prescindiendo de los flujos de inversión, las remesas de los migrantes o los intercambios de servicios. Las principales fuentes de información consultadas han sido las publicadas por el INE, ISTAC y la OMC en donde se recogen estadísticas oficiales basadas en los datos suministrados por la Agencia Tributaria del Ministerio de Economía y Hacienda.

Gestión de encuestas

[ES] Para favorecer la evaluación de la docencia, la Agencia Nacional de Evaluación de la Calidad y la Acreditación (a partir de ahora ANECA) pone en marcha el Programa de Apoyo a la Evaluación de la Actividad Docente del Profesorado Universitario (a partir de ahora DOCENTIA) con el objeto de apoyar a las universidades en el diseño de mecanismos propios para gestionar la calidad de la actividad docente del profesorado universitario y favorecer su desarrollo y reconocimiento. Un pilar fundamental en este procedimiento son las encuestas que los estudiantes realizan para valorar la calidad docente de sus profesores. El Gabinete de Evaluación Institucional (a partir de ahora GEI) de la Universidad de Las Palmas de Gran Canaria (a partir de ahora ULPGC) es el encargado de gestionar todo el proceso de encuestación y por este motivo, surge la inmensa necesidad de disponer de una aplicación informática que permita hacer un seguimiento de dicho proceso. Este proyecto es un sistema de gestión que permite conocer qué profesores de la ULPGC han sido valorados por sus alumnos y en qué asignaturas. El objetivo principal es hacer un seguimiento durante el proceso de encuestación para intentar asegurar que todos los profesores han sido valorados en al menos alguna de sus asignaturas. Solo los profesores que hayan sido valorados en al menos una de sus asignaturas podrán acceder a los grados de excelencia docente del Programa DOCENTIA-ULPGC. De ahí la importancia de este proyecto fin de grado.

Análisis bibliométrico de la productividad científica de las Cienias Históricas en Canarias en el período 1989-2010: problemas y perspectivas

[ES] En los últimos años se ha puesto de manifiesto la creciente necesidad de evaluar la actividad científica en España, realizada a partir de medios transparentes y objetivos. La evaluación permite conocer mejor el sistema científico de los países y regiones, poniendo de relieve sus problemas y ventajas y permitiendo adoptar medidas que favorezcan su desarrollo. También los propios investigadores son los primeros interesados en la utilización de métodos científicos cuantitativos y cualitativos con el fin de evaluar su propia actividad, asumiendo de forma natural que su actividad profesional sea evaluada con objetividad, independencia y transparencia. El presente estudio expone los problemas y perspectivas del proyecto de investigación “Análisis y evolución de la producción científica del área de Artes y Humanidades en Canarias en el periodo 1989-2009”, financiado por el Gobierno de Canarias a través de la Agencia Canaria de la Investigación, Innovación y Sociedad de la Información, así como los resultados preliminares en varias áreas de conocimiento del campo de Arte y Humanidades en las dos universidades canarias.

Análisis bibliométrico de la producción científica de las universidades canarias en las áreas de Ciencias Históricas en el periodo 1989-2010: resultados finales de un estudio

[ES] Se presentan los resultados finales del proyecto de investigación “Análisis y evolución de la producción científica del área de Artes y Humanidades en Canarias en el período 1989-2009”, financiado por el Gobierno de Canarias a través de la Agencia Canaria de la Investigación, Innovación y Sociedad de la Información, referidos a las áreas de conocimiento de Prehistoria, Historia Antigua, Historia Medieval, Historia Moderna, Historia Contemporánea e Historia del Arte. El estudio realizado permite confirmar diferencias sustanciales en los hábitos de publicación y en la visibilidad de las publicaciones del profesorado de las dos universidades canarias, según su especialidad.

Análisis geográfico de las actuales relaciones comerciales entre Canarias y Marruecos

[ES] En este trabajo formulamos como hipótesis de partida que Canarias, como frontera meridional de Europa, en un contexto de creciente internacionalización, tiene en los mercados africanos una gran baza histórica que desempeñar. Dado el interés general que este asunto suscita entre las ciencias sociales, se requiere abordarlo desde el análisis geográfico. Para cumplimentar este estudio se emplearon las estadísticas que ofrecen organismos oficiales como el Instituto Nacional de Estadística, Instituto Canario de Estadística, Agencia Estatal de la Administración Tributaria, Instituto de Comercio Exterior y entidades internacionales como la Conferencia de las Naciones Unidas para el Comercio y el Desarrollo (UNCTAD) y la Organización Mundial del Comercio (OCM).