Microbial carbon limitation : the need for integrating microorganisms into our understanding of ecosystem carbon cycling

Numerous studies have demonstrated that fertilization with nutrients such as nitrogen, phosphorus, and potassium increases plant productivity in both natural and managed ecosystems, demonstrating that primary productivity is nutrient limited in most terrestrial ecosystems. In contrast, it has been demonstrated that heterotrophic microbial communities in soil are primarily limited by organic carbon or energy. While this concept of contrasting limitations, that is, microbial carbon and plant nutrient limitation, is based on strong evidence that we review in this paper, it is often ignored in discussions of ecosystem response to global environment changes. The plant-centric perspective has equated plant nutrient limitations with those of whole ecosystems, thereby ignoring the important role of the heterotrophs responsible for soil decomposition in driving ecosystem carbon storage. To truly integrate carbon and nutrient cycles in ecosystem science, we must account for the fact that while plant productivity may be nutrient limited, the secondary productivity by heterotrophic communities is inherently carbon limited. Ecosystem carbon cycling integrates the independent physiological responses of its individual components, as well as tightly coupled exchanges between autotrophs and heterotrophs. To the extent that the interacting autotrophic and heterotrophic processes are controlled by organisms that are limited by nutrient versus carbon accessibility, respectively, we propose that ecosystems by definition cannot be 'limited' by nutrients or carbon alone. Here, we outline how models aimed at predicting non-steady state ecosystem responses over time can benefit from dissecting ecosystems into the organismal components and their inherent limitations to better represent plant-microbe interactions in coupled carbon and nutrient models

Actinobacterial Diversity in Volcanic Caves and Associated Geomicrobiological Interactions

16 páginas.-- 8 figuras.-- 2 tablas.-- 66 referencias.-- Material suplementario http://dx.doi.org/10.3389/fmicb.2015.01342Volcanic caves are filled with colorful microbial mats on the walls and ceilings. These volcanic caves are found worldwide, and studies are finding vast bacteria diversity within these caves. One group of bacteria that can be abundant in volcanic caves, as well as other caves, is Actinobacteria. As Actinobacteria are valued for their ability to produce a variety of secondary metabolites, rare and novel Actinobacteria are being sought in underexplored environments. The abundance of novel Actinobacteria in volcanic caves makes this environment an excellent location to study these bacteria. Scanning electron microscopy (SEM) from several volcanic caves worldwide revealed diversity in the morphologies present. Spores, coccoid, and filamentous cells, many with hair-like or knobby extensions, were some of the microbial structures observed within the microbial mat samples. In addition, the SEM study pointed out that these features figure prominently in both constructive and destructive mineral processes. To further investigate this diversity, we conducted both Sanger sequencing and 454 pyrosequencing of the Actinobacteria in volcanic caves from four locations, two islands in the Azores, Portugal, and Hawai'i and New Mexico, USA. This comparison represents one of the largest sequencing efforts of Actinobacteria in volcanic caves to date. The diversity was shown to be dominated by Actinomycetales, but also included several newly described orders, such as Euzebyales, and Gaiellales. Sixty-two percent of the clones from the four locations shared less than 97% similarity to known sequences, and nearly 71% of the clones were singletons, supporting the commonly held belief that volcanic caves are an untapped resource for novel and rare Actinobacteria. The amplicon libraries depicted a wider view of the microbial diversity in Azorean volcanic caves revealing three additional orders, Rubrobacterales, Solirubrobacterales, and Coriobacteriales. Studies of microbial ecology in volcanic caves are still very limited. To rectify this deficiency, the results from our study help fill in the gaps in our knowledge of actinobacterial diversity and their potential roles in the volcanic cave ecosystems.The authors acknowledge the Spanish Ministry of Economy and Competitiveness (project CGL2013-41674-P) and FEDER Funds for financial support. AM acknowledges the support from the Marie Curie Intra-European Fellowship of the European Commission's 7th Framework Programme (PIEF-GA-2012-328689). CR was funded by the Regional Fund for Science and Technology and Pro-Emprego program of the Regional Government of the Azores, Portugal [M3.1.7/F/013/2011, M3.1.7/F/030/2011]. Her work was partly supported by National funds from the Foundation for Science and Technology of the Portuguese Government, [Understanding Underground Biodiversity: Studies in Azorean Lava Tubes (reference PTDC/AMB/70801/2006]. The authors would like to thank the TRU Innovation in Research Grant, TRU UREAP Fund, Western Economic Diversification Canada Fund, Kent Watson (assisted with the Helmcken Falls Cave sample collection), Derrick Horne (UBC BioImaging Facility for the SEM work). We acknowledged the Canadian Ministry of Forests, Lands, and Natural Resource Operations for Park Use Permit#102172. This work was also supported by the Cave Conservancy of the Virginias, the Graduate Research Allocation Committee at UNM Biology, UNM Biology Grove Scholarship, the Student Research Allocation Committee at UNM, the National Speleological Society, the New Mexico Space Grant Consortium, the New Mexico Alliance for Minority Participation Program, the New Mexico Geological Society, and Kenneth Ingham Consulting. We acknowledge support from the UNM Molecular Biology Facility, which is supported by NIH grant number P20GM103452. The authors also wish to thank Fernando Pereira, Ana Rita Varela, Pedro Correia, Berta Borges, and Guida Pires for help during field and lab work in the Azores. The authors gratefully acknowledge the photographic contributions of Kenneth Ingham and Pedro Cardoso and Michael Spilde (SEM images). The authors would like to thank Dr. Steven Van Wagoner (TRU) and Drs. Julian Davies and Vivian Miao (UBC) for their invaluable comments in manuscript preparation. We gratefully acknowledge the help and collecting permits granted by the staff of El Malpais National Monument and Hawai'i Volcanoes National Park (USA).Peer reviewe

The formin INF2 regulates basolateral-to-apical transcytosis and lumen formation in association with Cdc42 and MAL2

Transcytosis is a widespread pathway for apical targeting in epithelial cells. MAL2, an essential protein of the machinery for apical transcytosis, functions by shuttling in vesicular carriers between the apical zone and the cell periphery. We have identified INF2, an atypical formin with actin polymerization and depolymerization activities, which is a binding partner of MAL2. MAL2-positive vesicular carriers associate with short actin filaments during transcytosis in a process requiring INF2. INF2 binds Cdc42 in a GTP-loaded-dependent manner. Cdc42 and INF2 regulate MAL2 dynamics and are necessary for apical transcytosis and the formation of lateral lumens in hepatoma HepG2 cells. INF2 and MAL2 are also essential for the formation of the central lumen in organotypic cultures of epithelial MDCK cells. Our results reveal a functional mechanism whereby Cdc42, INF2, and MAL2 are sequentially ordered in a pathway dedicated to the regulation of transcytosis and lumen formation. © 2010 Elsevier Inc.This work was supported by grants (BFU2006-01925, BFU2009-07886, and CONSOLIDER COAT CSD2009-00016) to M.A.A. from the Ministerio de Ciencia e Innovación (MICINN), Spain. R.M. is the holder of a contract from the Ramón y Cajal Program of the MICINN. The authors declare no competing financial interests

Prognostic Scores for Risk Stratification in Patients with Acute Heart Failure

Introducción: La insuficiencia cardíaca es una condición frecuente, progresiva y potencialmente mortal. La evaluación correcta del riesgo de los desenlaces en los casos agudos permitiría la optimización de la atención y de los recursos. Objetivo: Aplicar tres de las escalas existentes para la evaluación del riesgo de muerte intrahospitalaria en pacientes con falla cardíaca aguda a fin de conocer su desempeño. Material y métodos: Estudio con diseño de pronóstico en el que se incluyeron pacientes hospitalizados por el servicio de medicina interna con diagnóstico de falla cardíaca descompensada entre febrero de 2010 y marzo de 2013. Se aplicaron tres escalas de riesgo para evaluar la mortalidad intrahospitalaria: árbol de decisiones ADHERE, OPTIMIZE-HF y GWTG-HF. Se construyeron tablas de contingencia mediante el cálculo del desempeño para los diferentes puntos de corte, así como las curvas ROC de cada escala y luego se calcularon las áreas bajo la curva. Resultados: Se calculó el resultado de las escalas en 379 pacientes, de los cuales el 54% eran mujeres; la mediana de edad fue de 75 años, el 79% eran hipertensos y el 24% eran diabéticos. El área bajo la curva del OPTIMIZE-HF fue de 0,63 (IC 95% 0,53-0,73), la del GWTG-HF fue de 0,57 (IC 95% 0,49-0,65) y la del ADHERE fue de 0,58 (IC 95% 0,47-0,68). Conclusión: En una población de pacientes hospitalizados por falla cardíaca descompensada, las escalas de riesgo ADHERE, OPTIMIZE y GWTG-HF mostraron una pobre capacidad de discriminación del riesgo de muerte intrahospitalaria.Background: Heart failure is a common, progressive and potentially lethal condition. An adequate risk assessment in acute cases might optimize care and resources. Objective: The aim of this study was to apply three of the existent risk scores to predict in-hospital mortality in patients with acute heart failure in order to understand their performance. Methods: This prognostic study included patients hospitalized by the department of internal medicine with diagnosis of decompensated heart failure between February 2010 and March 2013. Three risk scores were used to evaluate in-hospital mortality: the ADHERE decision tree, the OPTIMIZE-HF score and the GWTG-HF score. Contingency tables were constructed using the performance of the different cutoff points and the ROC curves of each score; then, the areas under the curve were calculated. Results: Score results were calculated in 379 patients. Mean age was 75 years, 54% were women, 79% had hypertension, and 24% were diabetics. The area under the curve for the three risk scores was 0.63 (95% CI, 0.53-0.73) for OPTIMIZE-HF, 0.57 (95% CI, 0.49-0.65) for GWTG-HF and 0.58 (95% CI, 0.47-0.68) for ADHERE. Conclusion: In a population of patients hospitalized for decompensated heart failure, the ADHERE, OPTIMIZE and GWTGHF risk scores showed poor discrimination ability to predict in-hospital mortality

Desarrollo del derecho humano a un medio ambiente sano

Los motivos que impulsaron la presente investigación fue la carta emitida por el Comisariado Ejidal, quien nos expuso la problemática actual en la que se ven inmersos, como lo es la falta de aprovechamientos de recursos naturales y a su vez la falta de presupuesto para su cuidado y su preservación, lo cual trae como consecuencia diversos impactos ambientales.ITESO, A.C

Whose personal is more political? Experience in contemporary feminist politics

Whose personal is more political? This paper rethinks the role of experience in contemporary feminism, arguing that it can operate as a form of capital within abstracted and decontextualised debates which entrench existing power relations. Although experiential epistemologies are crucial to progressive feminist thought and action, in a neoliberal context in which the personal and emotional is commodified powerful groups can mobilise traumatic narratives to gain political advantage. Through case study analysis this paper shows how privileged feminists, speaking for others and sometimes for themselves, use experience to generate emotion and justify particular agendas, silencing critics who are often from more marginalised social positions. The use of the experiential as capital both reflects and perpetuates the neoliberal invisibilisation of structural dynamics: it situates all experiences as equal, and in the process fortifies existing inequalities. This competitive discursive field is polarising, and creates selective empathies through which we tend to discredit others¹ realities instead of engaging with their politics. However, I am not arguing for a renunciation of the politics of experience: instead, I ask that we resist its commodification and respect varied narratives while situating them in a structural frame

110 Years of Avipoxvirus in the Galapagos Islands

The role of disease in regulating populations is controversial, partly owing to the absence of good disease records in historic wildlife populations. We examined birds collected in the Galapagos Islands between 1891 and 1906 that are currently held at the California Academy of Sciences and the Zoologisches Staatssammlung Muenchen, including 3973 specimens representing species from two well-studied families of endemic passerine birds: finches and mockingbirds. Beginning with samples collected in 1899, we observed cutaneous lesions consistent with Avipoxvirus on 226 (6.3%) specimens. Histopathology and viral genotyping of 59 candidate tissue samples from six islands showed that 21 (35.6%) were positive for Avipoxvirus, while alternative diagnoses for some of those testing negative by both methods were feather follicle cysts, non-specific dermatitis, or post mortem fungal colonization. Positive specimens were significantly nonrandomly distributed among islands both for mockingbirds (San Cristobal vs. Espanola, Santa Fe and Santa Cruz) and for finches (San Cristobal and Isabela vs. Santa Cruz and Floreana), and overall highly significantly distributed toward islands that were inhabited by humans (San Cristobal, Isabela, Floreana) vs. uninhabited at the time of collection (Santa Cruz, Santa Fe, Espanola), with only one positive individual on an uninhabited island. Eleven of the positive specimens sequenced successfully were identical at four diagnostic sites to the two canarypox variants previously described in contemporary Galapagos passerines. We conclude that this virus was introduced late in 1890′s and was dispersed among islands by a variety of mechanisms, including regular human movements among colonized islands. At present, this disease represents an ongoing threat to the birds on the Galapagos Islands

Trisubstituted Pyrimidines as Efficacious and Fast-acting Antimalarials

In this paper we describe the optimization of a phenotypic hit against Plasmodium falciparum, based on a trisubstituted pyrimidine scaffold. This led to compounds with good pharmacokinetics and oral activity in a P. berghei mouse model of malaria. The most promising compound (13) showed a reduction in parasitemia of 96% when dosed at 30 mg/kg orally once a day for 4 days in the P. berghei mouse model of malaria. It also demonstrated a rapid rate of clearance of the erythrocytic stage of P. falciparum in the SCID mouse model with an ED90 of 11.7 mg/kg when dosed orally. Unfortunately, the compound is a potent inhibitor of cytochrome P450 enzymes, probably due to a 4-pyridyl substituent. Nevertheless, this is a lead molecule with a potentially useful antimalarial profile, which could either be further optimized or be used for target hunting