North Atlantic Oscillation and fisheries management during global climate change

Reviews in Fish Biology and Fisheries - The North Atlantic Oscillation (NAO) is the most important large-scale climatic oscillation affecting the North Atlantic region. The variability introduced...     

Presence and molecular characterization of Clostridium difficile and Clostridium perfringens in intestinal compartments of healthy horses

ABSTRACT: BACKGROUND: Clostridium difficile and Clostridium perfringens are commonly associated with colitis in equids, but healthy carriers exist. Scarce information is available on the prevalence of Clostridium spp. in gastrointestinal compartments other than faeces in healthy horses, and it is unknown whether faecal samples are representative of proximal compartments. The objectives were to investigate the prevalence of C. difficile and C. perfringens in different intestinal compartments of healthy adult horses and to determine whether faecal samples are representative of colonization in proximal sites and overall carrier status. RESULTS: Toxigenic C. difficile was isolated from 14/135 (10.3%) samples from 8/15 (53.3%) horses. Between zero and three sites were positive per horse, and multiple sites were positive in four horses. Isolates were recovered from duodenum, jejunum, ileum, right dorsal colon, small colon and rectum. When multiple compartments were positive in a single horse, two different C. difficile ribotypes were always present. Clostridium perfringens Type A (CPE, beta2 toxin gene negative) was recovered from the left ventral colon of one horse (0.74%, 1/135 samples). Agreement between faeces and overall C. difficile carrier status was good. CONCLUSIONS: Clostridium difficile can be found in different compartments of the gastrointestinal tract of healthy horses, and multiple strains can be present in an individual horse. The prevalence of C. perfringens in healthy adult hoses was low, consistent with previous reports. Faecal samples were representative for presence of C. difficile in proximal compartments in 5/8 horses (63%) but were not representative for the specific strain.     

Developing a Social Autopsy Tool for Dengue Mortality: A Pilot Study

BackgroundDengue fever is a public health problem in the tropical and sub-tropical world. Dengue cases have grown dramatically in recent years as well as dengue mortality. Colombia has experienced periodic dengue outbreaks with numerous dengue related-deaths, where the Santander department has been particularly affected. Although social determinants of health (SDH) shape health outcomes, including mortality, it is not yet understood how these affect dengue mortality. The aim of this pilot study was to develop and pre-test a social autopsy (SA) tool for dengue mortality.ConclusionsThe SA tool is based on the scientific literature, a validated conceptual framework, researchers’ and health professionals’ expertise, and a pilot study. It is the first time that a SA tool has been created for the dengue mortality context. Our work furthers the study on SDH and how these are applied to neglected tropical diseases, like dengue. This tool could be integrated in surveillance systems to provide complementary information on the modifiable and avoidable death-related factors and therefore, be able to formulate interventions for dengue mortality reduction.     

The phytotoxic effect of exogenous ethanol on Euphorbia heterophylla L.

This study investigated the effects of exogenously applied ethanol on Euphorbia heterophylla L., a troublesome weed in field and plantation crops. Ethanol at concentrations ranging from 0.25 to 1.5% caused a dose-dependent inhibition of germination and growth of E. heterophylla. Measurements of respiratory activity and alcohol dehydrogenase (E.C. 1.1.1.1) activity during seed imbibition and initial seedling growth revealed that ethanol induces a prolongation of hypoxic conditions in the growing tissues. In isolated mitochondria, ethanol inhibited the respiration coupled to ADP phosphorylation, an action that probably contributed to modifications observed in the respiratory activity of embryos. A comparison of the effects of methanol, ethanol, propanol and acetaldehyde on germination and growth of E. heterophylla indicates that alcohol dehydrogenase activity is required for the observed effects, with the conversion of ethanol to acetaldehyde playing a role in the ethanol-induced injuries.     

Production of a Rhizopus oryzae lipase from Pichia pastoris using alternative operational strategies

Different cultivation strategies have been compared for the production of Rhizopus oryzae lipase (ROL) from Pichia pastoris. Several drawbacks have been found using a methanol non-limited fed-batch. On the one hand, oxygen limitation appeared at early cell dry weights and, on the other hand, high cell death was observed. A temperature limited fed-batch has been proposed to solve both problems. However, in our case study a methanol non-limited fed-batch results in better productivities. Finally, a lower salt medium were used to overcome cell death problems and a temperature limited fed-batch was applied thereafter to solve oxygen transfer limitations. This combined strategy has resulted in lower productivities when compared to a methanol non-limited fed-batch. However the culture could be longer prolonged and a 1.3-fold purer final product was obtained mainly due to cell death reduction.     

Genetic demography of Antioquia (Colombia) and the Central Valley of Costa Rica

We report a comparative genetic characterization of two population isolates with parallel demographic histories: the Central Valley of Costa Rica (CVCR) and Antioquia (in northwest Colombia). The analysis of mtDNA, Y-chromosome and autosomal polymorphisms shows that Antioquia and the CVCR are genetically very similar, indicating that closely related parental populations founded these two isolates. In both populations, the male ancestry is predominantly European, whereas the female ancestry is mostly Amerind. In agreement with their isolation, the Amerindian mtDNA diversity of Antioquia and the CVCR is typical of ethnically-defined native populations and is markedly lower than in other Latin American populations. A comparison of linkage disequilibrium (LD) at 18 marker pairs in Antioquia and the CVCR shows that markers in LD in both populations are located at short genetic distances (相似文献   

Phagocytosis in the developing CNS: more than clearing the corpses

Cell corpses generated during CNS development are eliminated through phagocytosis performed by a variety of cells, including mesenchyme-derived macrophages and microglia, or glial cells originating in the neurogenic ectoderm. Mounting evidence indicates that in different species, phagocytes not only clear cell corpses but also engulf still-living neural cells or axons, and thereby promote cell death or axon pruning. Knowledge of the mechanisms of corpse recognition by engulfing cells provides molecular signals to this new role for phagocytes. These observations support a conserved and instructive role for phagocytosis in the execution of regressive events during neurogenesis.     

On the robustness of complex heterogeneous gene expression networks

We analyze a continuous gene expression model on the underlying topology of a complex heterogeneous network. Numerical simulations aimed at studying the chaotic and periodic dynamics of the model are performed. The results clearly indicate that there is a region in which the dynamical and structural complexity of the system avoid chaotic attractors. However, contrary to what has been reported for Random Boolean Networks, the chaotic phase cannot be completely suppressed, which has important bearings on network robustness and gene expression modeling.