239 research outputs found

    Review: Formation and Metabolic Function of Coral Rubble Biofilms in the Reef Ecosystem

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    When coral dies, their calcareous skeletons constitute coral rubble in conjunction with the cementing activity of coralline algae and bacteria, creating a secondary reef structure which takes from years to decades to form. Healthy coral reefs differ from coral—rubble dominated reefs in microbial taxonomic composition and metabolic functional roles. The metabolisms of healthy reefs are dominated by autotrophic pathways, where carbon and nitrogen fixation dominate, while the metabolism of rubble—dominated reefs predominate in degradation of organic matter. Nitrogen fixation is 3 orders of magnitude lower in rubble—dominated reefs than in healthy reefs. Coral—rubble harbors a vast diversity of microbes that can precipitate carbonate through coupling several metabolic processes including photosynthesis, ureolysis, ammonification, denitrification, sulfate reduction, methane oxidation, and anaerobic sulfide oxidation. All these metabolic processes were found in rubble microbial communities, but ammonification and sulfate reduction were most prevalent. Anthropogenic and non—anthropogenic perturbations of healthy coral reefs in the past decades have led to the prevalence of rubble—dominated reefs in areas of the Caribbean where the ecological and functional shifts of the community still need further study

    Evaluación del sesgo en las clasificaciones taxonómicas del índice cefálico

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    El índice cefálico (ic) ha sido ampliamente utilizado para establecer categorías taxonómicas humanas. Aunque su significado biológico ha sido discutido, pocos trabajos han analizado la relación numérica del índice y sus clasificaciones. Aquí se aborda uno de los sesgos introducidos por la transformación en categorías de clase (braquicefalia, mesocefalia y dolicocefalia) de la distribución continua del ic, se analiza el efecto que tiene en la varianza poblacional y en la densidad de los datos. Por medio de la Howells World Data Set recurrimos al coeficiente de determinación como estimador de la cantidad de información que se conserva posterior a la trans- formación categórica del ic. Nuestros resultados indican que las clasificaciones del ic son un reducto de la variabilidad biológica craneal de las poblaciones humanas. La adopción de modelos no lineales hiperdimensionales y multivariados representa un mejor acercamiento a la covariación de las formas biológicas.The cephalic index (ic) has been widely used as one of the higher profile tools to establish human taxonomy categories. Although it has been discussed the biological sense of the cephalic index, few studies analyzed the mathematics relations of the ratio and their classifications. In this paper, we address one of the biases introduced by the transformation into class categories (brachycephaly, mesocephaly and dolichocephaly) of the continuous distribution of IC, analyzing the effect in the population variance and the density of the data. Thus, we used Howells World Data Set for determination coefficient as an estimate of amount of information retained after processing IC categories. Our results indicate that the ratings of the IC are a haven of cranial biological variability of human populations. The adoption of hyperdimensional non-linear and multivariate models represents a better approach to the covariance of biological forms.Fil: Gomez Valdes, Jorge A.. Universidad Nacional Autónoma de México; MéxicoFil: Quinto Sanchez, Mirsha Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentin

    Heat transfer study in the elements of an absorption refrigeration system operating in partial heat loads

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    The study presented in this paper describes the experimental rig and the methodology used to carry out the experimental research for an absorption refrigeration system operating in partial heat loads. The refrigeration performance, was analysed using a nominal thermal load (100%) and two partial loads of 60% and 80% and two overloads of 120% and 140%.В роботі дано опис експериментального обладнання і методики, що використовувалися для отримання даних на абсорційній холодильній системі при різних теплових навантаженнях. Холодильні характеристики були проаналізовані при номінальному тепловому навантаженні (100%), а також при двох знижених навантаженнях (60% і 80%) і двох підвищенних теплових навантаженнях (120% и 140%).В исследовании, представленном в статье, описана экспериментальная установка и методика, использованные для получения экспериментальных данных на абсорбционной охладительной системе при разных тепловых нагрузках. Холодильные характеристики были проанализированы при номинальной тепловой нагрузке (100%), а также двух пониженных нагрузках (60% и 80%) и двух повышенных тепловых нагрузках (120% и 140%)

    Hyper, a Hydrogen Peroxide Sensor, Indicates the Sensitivity of the Arabidopsis Root Elongation Zone to Aluminum Treatment

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    Emerging evidence indicates that some reactive oxygen species (ROS), such as the superoxide anion radical and hydrogen peroxide (H2O2), are central regulators of plant responses to biotic and abiotic stresses. Thus, the cellular levels of ROS are thought to be tightly regulated by an efficient and elaborate pro- and antioxidant system that modulates the production and scavenging of ROS. Until recently, studies of ROS in plant cells have been limited to biochemical assays and the use of fluorescent probes; however, the irreversible oxidation of these fluorescent probes makes it impossible to visualize dynamic changes in ROS levels. In this work, we describe the use of Hyper, a recently developed live cell probe for H2O2 measurements in living cells, to monitor oxidative stress in Arabidopsis roots subjected to aluminum treatment. Hyper consists of a circularly permuted YFP (cpYFP) inserted into the regulatory domain of the Escherichia coli hydrogen peroxide-binding protein (OxyR), and is a H2O2-specific ratiometric, and therefore quantitative, probe that can be expressed in plant and animal cells. Now we demonstrate that H2O2 levels drop sharply in the elongation zone of roots treated with aluminum. This response could contribute to root growth arrest and provides evidence that H2O2 is involved in early Al sensing

    An Autophagy-Related Kinase Is Essential for the Symbiotic Relationship between Phaseolus vulgaris and Both Rhizobia and Arbuscular Mycorrhizal Fungi

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    Eukaryotes contain three types of lipid kinases that belong to the phosphatidylinositol 3-kinase (PI3K) family. In plants and Saccharomyces cerevisiae, only PI3K class III family members have been identified. These enzymes regulate the innate immune response, intracellular trafficking, autophagy, and senescence. Here, we report that RNAi-mediated downregulation of common bean (Phaseolus vulgaris) PI3K severely impaired symbiosis in composite P. vulgaris plants with endosymbionts such as Rhizobium tropici and Rhizophagus irregularis. Downregulation of Pv-PI3K was associated with a marked decrease in root hair growth and curling. Additionally, infection thread growth, root-nodule number, and symbiosome formation in root nodule cells were severely affected. Interestingly, root colonization by AM fungi and the formation of arbuscules were also abolished in PI3K loss-of-function plants. Furthermore, the transcript accumulation of genes encoding proteins known to interact with PI3K to form protein complexes involved in autophagy was drastically reduced in these transgenic roots. RNAi-mediated downregulation of one of these genes, Beclin1/Atg6, resulted in a similar phenotype as observed for transgenic roots in which Pv-PI3K had been downregulated. Our findings show that an autophagy-related process is crucial for the mutualistic interactions of P. vulgaris with beneficial microorganismsInstituto de Fisiología y Recursos Genéticos VegetalesFil: Estrada-Navarrete, Georgina. Universidad Nacional Autónoma de México. Instituto de Biotecnología. Departamento de Biología Molecular de Plantas; MéxicoFil: Cruz-Mireles, Neftaly. Universidad Nacional Autónoma de México. Instituto de Biotecnología. Departamento de Biología Molecular de Plantas; MéxicoFil: Lascano, Hernán Ramiro. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Estudios Agropecuarios (UDEA); ArgentinaFil: Lascano, Hernán Ramiro. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales. ArgentinaFil: Alvarado-Affantranger, Xóchitl. Universidad Nacional Autónoma de México. Instituto de Biotecnología. Laboratorio Nacional de Microscopía Avanzada; MéxicoFil: Hernández-Barrera, Alejandra. Universidad Nacional Autónoma de México. Instituto de Biotecnología. Departamento de Biología Molecular de Plantas; MéxicoFil: Barraza, Aarón. Universidad Nacional Autónoma de México. Instituto de Biotecnología. Departamento de Biología Molecular de Plantas; MéxicoFil: Olivares, Juan E. Universidad Nacional Autónoma de México. Instituto de Biotecnología. Departamento de Biología Molecular de Plantas; MéxicoFil: Arthikala, Manoj-Kumar. Universidad Nacional Autónoma de México. Escuela Nacional de Estudios Superiores-Unidad León; MéxicoFil: Cárdenas, Luis. Universidad Nacional Autónoma de México. Instituto de Biotecnología. Departamento de Biología Molecular de Plantas; MéxicoFil: Quinto, Carmen. Universidad Nacional Autónoma de México. Instituto de Biotecnología. Departamento de Biología Molecular de Plantas; MéxicoFil: Sanchez, Federico. Universidad Nacional Autónoma de México. Instituto de Biotecnología. Departamento de Biología Molecular de Plantas; Méxic

    Predicting Physical Features and Diseases by DNA Analysis: Current Advances and Future Challenges

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    The 'omics' era and its concomitant technological advances have brought great insight into genetics. One of the most promising fields within human genetics is the prediction of physical traits from analysis of genetic material. Besides the predictive potential of DNA, the traceability of pathogenic agents in the human body through molecular analysis is also a field to be further exploited. In this review, we aim to discuss specific aspects of phenotypic prediction by analysing DNA, with special emphasis on normal variation, and the application of a technology known as ‘Forensic DNA Phenotyping’ (FDP). We also suggest the term ‘Phenotype Informative Markers’ (PIMs) to designate any molecular markers responsible for normal or pathological human phenotypic variation. In addition, we raise some recommendations related to forensic genetics, the molecular diagnosis of human diseases, and the traceability of pathogens in the human body, giving special emphasis to the need for validation of these tests with strict protocols. Some relevant concerns about privacy, ethics, and legality of such predictions have also been discussed. Finally, we look at perspectives on the use of epigenetic tools, and quote some examples of what has been done in this specific field.Fil: Silva de Cerqueira, Caio Cesar. Scientific Police Of Sao Paulo State; BrasilFil: Ramallo, Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Ciencias Sociales y Humanas; ArgentinaFil: Hünemeier, Tábita. Universidade de Sao Paulo; BrasilFil: de Azevedo, Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Ciencias Sociales y Humanas; ArgentinaFil: Quinto Sanchez, Mirsha Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Ciencias Sociales y Humanas; ArgentinaFil: Paschetta, Carolina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Ciencias Sociales y Humanas; ArgentinaFil: Cintas, Celia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Ciencias Sociales y Humanas; ArgentinaFil: González, Marina Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Ciencias Sociales y Humanas; ArgentinaFil: Schüler-faccini, Lavinia. Universidade Federal do Rio Grande do Sul; Brasil. National Institute of Medical Genetics Population; BrasilFil: Bortolini, María Cátira. Universidade Federal do Rio Grande do Sul; BrasilFil: González José, Rolando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Ciencias Sociales y Humanas; Argentin

    Ventricular tachycardia burden reduction after substrate ablation: predictors of recurrence.

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    BACKGROUND Substrate-based ventricular tachycardia (VT) ablation is a first-line treatment in patients with structural cardiac disease and sustained VT refractory to medical therapy. Despite technological improvements and increased knowledge of VT substrate, recurrence still is frequent. Published data are lacking on the possible reduction in VT burden after ablation despite recurrence. OBJECTIVE The purpose of this study was to assess VT burden reduction during long-term follow-up after substrate ablation and identify predictors of VT recurrence. METHODS We analyzed 234 consecutive VT ablation procedures in 207 patients (age 63 6 14.9 years; 92% male; ischemic heart disease in 65%) who underwent substrate ablation in a single center from 2013 to 2018. RESULTS After follow-up of 3.14 6 1.8 years, the VT recurrence rate was 41.4%. Overall, a 99.6% reduction in VT burden (median VT episodes per year: preprocedural 3.546 [1.347-13.951] vs postprocedural 0.001 [0-0.689]; P 5 .001) and a 96.3% decrease in implantable cardioverter-defibrillator (ICD) shocks (preprocedural 1.145 [0.118-4.467] vs postprocedural 0.042 [0-0.111] per year; P 5 .017) were observed. In the subgroup of patients who experienced VT recurrences, VT burden decreased by 69.2% (median VT episodes per year: preprocedural 2.876 [1.105-8.801] vs postprocedural 0.882 [0.505-2.283]; P ,.001). Multivariable analysis showed persistence of late potentials (67% vs 19%; hazard ratio 3.18 [2.18- 6.65]; P ,.001) and lower left ventricular ejection fraction (EF) (30 [25-40] vs 39 [30-50]; P 5 .022) as predictors of VT recurrence. CONCLUSION Despite a high recurrence rate during long-term follow-up, substrate-based VT ablation is related to a large reduction in VT burden and a decrease in ICD therapies. Lower EF and persistence of late potentials are predictors of recurrence. KEYWORDS Arrhythmic burden reduction; Implantable cardioverter-defibrillator shock prevention; Ventricular tachycardia ablation; Ventricular tachycardia recurrence predictors; Ventricular tachycardia storm; Ventricular tachycardia substrate ablatio

    The impact of socioeconomic and phenotypic traits on self-perception of ethnicity in Latin America

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    Self-perception of ethnicity is a complex social trait shaped by both, biological and non-biological factors. We developed a comprehensive analysis of ethnic self-perception (ESP) on a large sample of Latin American mestizos from five countries, differing in age, socio-economic and education context, external phenotypic attributes and genetic background. We measured the correlation of ESP against genomic ancestry, and the influence of physical appearance, socio-economic context, and education on the distortion observed between both. Here we show that genomic ancestry is correlated to aspects of physical appearance, which in turn affect the individual ethnic self-perceived ancestry. Also, we observe that, besides the significant correlation among genomic ancestry and ESP, specific physical or socio-economic attributes have a strong impact on self-perception. In addition, the distortion among ESP and genomic ancestry differs across age ranks/countries, probably suggesting the underlying effect of past public policies regarding identity. Our results indicate that individuals’ own ideas about its origins should be taken with caution, especially in aspects of modern life, including access to work, social policies, and public health key decisions such as drug administration, therapy design, and clinical trials, among others
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