Constitutive and regulated expression vectors to construct polyphosphate deficient bacteria

<p>Abstract</p> <p>Background</p> <p>Inorganic polyphosphate (polyP), a polymer of tens or hundreds of phosphate residues linked by ATP-like bonds, is found in all organisms and performs a wide variety of functions. PolyP is synthesized in bacterial cells by the actions of polyphosphate kinases (PPK1 and PPK2) and degraded by an exopolyphosphatase (PPX). Bacterial cells with polyP deficiencies are impaired in many structural and important cellular functions such as motility, quorum sensing, biofilm formation and virulence. Knockout mutants of the <it>ppk1 </it>gene have been the most frequent strategy employed to generate polyP deficient cells.</p> <p>Results</p> <p>As an alternative method to construct polyP-deficient bacteria we developed constitutive and regulated broad-host-range vectors for depleting the cellular polyP content. This was achieved by the overexpression of yeast exopolyphosphatase (PPX1). Using this approach in a polyphosphate accumulating bacteria (<it>Pseudomonas sp</it>. B4), we were able to eliminate most of the cellular polyP (>95%). Furthermore, the effect of overexpression of PPX1 resembled the functional defects found in motility and biofilm formation in a <it>ppk1 </it>mutant from <it>Pseudomonas aeruginosa </it>PAO1. The plasmids constructed were also successfully replicated in other bacteria such as <it>Escherichia coli, Burkholderia </it>and <it>Salmonella</it>.</p> <p>Conclusion</p> <p>To deplete polyP contents in bacteria broad-host-range expression vectors can be used as an alternative and more efficient method compared with the deletion of <it>ppk </it>genes. It is of great importance to understand why polyP deficiency affects vital cellular processes in bacteria. The construction reported in this work will be of great relevance to study the role of polyP in microorganisms with non-sequenced genomes or those in which orthologs to <it>ppk </it>genes have not been identified.</p

Oxygen declines and the shoaling of the hypoxic boundary in the California Current

6 páginas, 4 figuras, 1 tabla.We use hydrographic data from the California Cooperative Oceanic Fisheries Investigations program to explore the spatial and temporal variability of dissolved oxygen (DO) in the southern California Current System (CCS) over the period 1984–2006. Large declines in DO (up to 2.1 μmol/kg/y) have been observed throughout the domain, with the largest relative DO declines occurring below the thermocline (mean decrease of 21% at 300 m). Linear trends were significant (p < 0.05) at the majority of stations down to 500 m. The hypoxic boundary (∼60 μmol/kg) has shoaled by up to 90 m within portions of the southern CCS. The observed trends are consistent with advection of low-DO waters into the region, as well as decreased vertical oxygen transport following near-surface warming and increased stratification. Expansion of the oxygen minimum layer could lead to cascading effects on benthic and pelagic ecosystems, including habitat compression and community reorganization.We acknowledge the California Current Ecosystem Long-Term Ecosystem Research (CCE-LTER) project, supported by a grant from NSF (OCE-0417616), and grants from the NSF (OCE-0526640), the David and Lucile Packard Foundation and the NOAA Fisheries and the Environment (FATE) program.Peer reviewe

Características del deterioro cognitivo en el adulto mayor hospitalizado a nivel nacional

Determinar la frecuencia y grado de deterioro cognitivo del adulto mayor hospitalizado en el Perú, así como su asociación con otros síndromes y problemas geriátricos. En base a la información del estudio «Valoración Geriátrica Integral en adultos mayores hospitalizados a nivel nacional (Perú)», se incluyeron a 312 pacientes de 60 años o más. Se evaluó la frecuencia y severidad del deterioro cognitivo; y se comparó estos resultados con los principales síndromes y problemas geriátricos. Se encontró una frecuencia de deterioro cognitivo moderado-severo de 22.11%. Se encontró asociación significativa entre deterioro cognitivo y edad, grado de instrucción (analfabeto), situación socioeconómica, confusión aguda, deprivación sensorial auditiva, inmovilidad, caídas, incontinencia urinaria y fecal, desnutrición, depresión establecida y estatus funcional. La presencia de insomnio y deprivación visual no tuvo presentó asociación significativa. La frecuencia de deterioro cognitivo en la población adulta mayor hospitalizada es elevada. Se encontró que el deterioro cognitivo estuvo asociado a múltiples y diversos problemas y síndromes geriátricos.&nbsp

TOXOPLASMOSIS COMO AGENTE CAUSAL DE ABORTOS EN ALPACAS

El estudio tuvo por objetivo determinar la asociación del T. gondii con los abortos en el primer, segundo y tercer trimestre de gestación, así como su relación con la mortalidad perinatal en la alpaca. El estudio se realizó en el Centro de Investigación y Desarrollo de Camélidos Sudamericanos-Lachocc de la Universidad Nacional de Huancavelica, a una altura de 4450 msnm, durante la campaña reproductiva de enero de 1999 a marzo de 2000, a través del monitoreo de anticuerpos de T. gondii, mediante la técnica de Hemoaglutinación Indirecta (HAI). Se evaluaron 332 alpacas hembras previo al empadre obteniéndose una seroprevalencia de 36.5% (121/332). Con 108 alpacas seronegativas se siguió su seroconversión obteniéndose una incidencia acumulada de 25% (27/108) a los 270 días después del empadre. La tasa de fertilidad total fue 70.4% (76/108), estando infectadas por T. gondii el 27.6% (21/76) sin haber diferencia significativa en fertilidad entre animales positivos y negativos a T. gondii. Las tasas de aborto para los periodos de 90 a 180, 181 a 270, y 271 a 330 días de gestación fueron de 6.6, 5.6 y 7.6%, respectivamente, y la tasa de mortalidad perinatal fue 8.1% sin haber diferencia estadística a la prueba de Fisher entre alpacas negativas e infectadas por T. gondii. Además, se encontró que la primoinfección de T. gondii en alpacas hembras es independiente de la edad pero que las alpacas seropositivas presentan 3.3 veces mayor riesgo de aborto que las seronegativas.El estudio tuvo por objetivo determinar la asociación del T. gondii con los abortos en el primer, segundo y tercer trimestre de gestación, así como su relación con la mortalidad perinatal en la alpaca. El estudio se realizó en el Centro de Investigación y Desarrollo de Camélidos Sudamericanos-Lachocc de la Universidad Nacional de Huancavelica, a una altura de 4450 msnm, durante la campaña reproductiva de enero de 1999 a marzo de 2000, a través del monitoreo de anticuerpos de T. gondii, mediante la técnica de Hemoaglutinación Indirecta (HAI). Se evaluaron 332 alpacas hembras previo al empadre obteniéndose una seroprevalencia de 36.5% (121/332). Con 108 alpacas seronegativas se siguió su seroconversión obteniéndose una incidencia acumulada de 25% (27/108) a los 270 días después del empadre. La tasa de fertilidad total fue 70.4% (76/108), estando infectadas por T. gondii el 27.6% (21/76) sin haber diferencia significativa en fertilidad entre animales positivos y negativos a T. gondii. Las tasas de aborto para los periodos de 90 a 180, 181 a 270, y 271 a 330 días de gestación fueron de 6.6, 5.6 y 7.6%, respectivamente, y la tasa de mortalidad perinatal fue 8.1% sin haber diferencia estadística a la prueba de Fisher entre alpacas negativas e infectadas por T. gondii. Además, se encontró que la primoinfección de T. gondii en alpacas hembras es independiente de la edad pero que las alpacas seropositivas presentan 3.3 veces mayor riesgo de aborto que las seronegativas

Identificación inmunohistoquímica de las células productoras de somatostatina y polipéptido pancreático en páncreas de alpacas (Vicugna pacos)

The aim of this study was to identify and evaluate gamma (PP) and delta cells in alpaca pancreas by immunohistochemistry (IHC). Samples were obtained from 30 alpacas from the southern highlands of Peru (crías, juveniles and adults). Histological sections of 5 μm thickness (3 per lobe and 2 of the body) were used. A commercial kit of IHC and polyclonal antibodies (anti-PP and anti-SSTR3) were used to identify PP and delta cells. Rat pancreas samples were used as positive controls. The intensity of the marking was qualitatively classified between 0 (no marking) and 3 (strong marking). PP cells were present in all age groups, mainly in the body and right lobe of the pancreas, being observed mainly in the periphery and intermediate zone of the islets with a medium and strong marking. Delta cells were present in both lobes until 4 months of age, without being observed in juveniles or adults. Delta cells were observed mainly on the periphery of the islets with a light marking.El estudio tuvo por finalidad identificar y evaluar las células gamma (PP) y delta en páncreas de alpacas mediante inmunohistoquímica (IHQ). Las muestras se obtuvieron de 30 alpacas de la sierra sur del Perú (crías, jóvenes y adultas). Se utilizaron cortes histológicos de 5 μm de espesor (3 por lóbulo y 2 del cuerpo). Se usó un kit comercial de IHQ y anticuerpos policlonales (anti-PP y anti-SSTR3) para identificar las células PP y delta, así como muestras de páncreas de rata como controles positivos. La intensidad de la marcación se clasificó cualitativamente entre 0 (sin marcación) hasta 3 (marcación fuerte). Las células PP estaban presentes en todos los grupos etarios, principalmente en el cuerpo y lóbulo derecho del páncreas, observándose principalmente en la periferia y zona intermedia de los islotes con una marcación media y fuerte. Las células delta estaban presentes en ambos lóbulos hasta los 4 meses de edad, sin observarse en juveniles ni en adultos. Las células delta se observaron principalmente en la periferia de los islotes con una marcación leve

Enfoque SIAL para implementar un sello de calidad en la tuna orgánica rojo vigor (Opuntia ficus-indica L. Mill.)

Objective: to analyze from the SIAL approach the territories of Chapulco and San Sebastián Villanueva in Puebla, Mexico, to determine the feasibility of obtaining a quality seal for red vigor tuna (Opuntia ficus-indica L. Mill.), of organic production. Design/methodology/approach: using the SIAL approach, four criteria were determined in the delimitation of the territory, which were: physical aspects, local history and reputation of the product, local practices and location of the producers. Likewise, the attributes of the territory in relation to the tuna product were identified, from the producers' perspective, through participatory workshops. Results: both territories have edaphoclimatic conditions for tuna farming and a historical trajectory dating back to pre-Hispanic times, generationally inherited know-how and they are collectively organized. However, the cultivation of red vigor organic tuna in San Sebastián is a role model for other localities and States, since it has developed its own technology based on experience and has had greater organizational growth. Limitations on study/implications: due to the organizational dynamics in the Chapulco territory, the process of obtaining the Fair Trade quality seal may be delayed since they do not have strong institutional links. Findings/conclusions: it is possible to manage a Denomination of Origin for San Sebastián Villanueva, because it has been possible to integrate the links of the productive chain. In the case of Chapulco, the Fair Trade Seal is suggested due to the territorial and social dynamics that this territory presentsObjetivo: analizar desde el enfoque SIAL los territorios de Chapulco y San Sebastián Villanueva en Puebla, México, para determinar la factibilidad de obtener un sello de calidad para la tuna rojo vigor (Opuntia ficus-indica L. Mill.) de producción orgánica. Diseño/metodología/aproximación: utilizando el enfoque SIAL se determinaron cuatro criterios en la delimitación del territorio que fueron: aspectos físicos, historia local y reputación del producto, prácticas locales y localización de los productores. Asimismo, se identificaron los atributos del territorio con relación al producto tuna, desde la perspectiva de los productores mediante talleres participativos. Resultados: ambos territorios cuentan con las condiciones edafoclimáticas para el cultivo de la tuna y una trayectoria histórica que data de la época prehispánica, saber y hacer heredados generacionalmente, y están organizados colectivamente. Sin embargo, el cultivo de tuna rojo vigor orgánica en San Sebastián es un modelo a seguir para otras localidades y estados, ya que ha desarrollado tecnología propia con base en la experiencia y ha tenido mayor crecimiento organizacional. Limitaciones del estudio/implicaciones: debido a las dinámicas organizativas en el territorio de Chapulco es posible que se retrase el proceso de la obtención del sello de calidad Fair Trade ya que no cuentan con vínculos institucionales sólidos. Hallazgos/conclusiones: es posible la gestión de una Denominación de Origen para San Sebastián Villanueva ya que ha logrado integrar los eslabones de la cadena productiva. Para Chapulco se sugiere el sello de Comercio Justo debido a las dinámicas territoriales y sociales que presenta este territorio

Alongshore variability of the California Current System from Central to Baja California in winter and spring 2003, physical, chemical and biological properties

Poster.-- American Society of Limnology and Oceanography and the Oceanography Society, Honolulu, Hawaii (USA), 15-20 febrero 2004Sixteen stations along the continental slope of western North America were occupied in February 18-27 and May 22-31, 2003, and form a meridional section from Monterey Bay, California (37º N, 122º W) to Cabo San Lucas, Mexico (23º N, 110º W). Our purpose was to compare trends in California Current (CC), Inshore Countercurrent (ICC) and California Undercurrent (CUC) properties with latitude, and between winter and spring conditions. In winter, coastal upwelling was near zero and the along-transect dynamic height was high and flat, allowing the ICC to advect tropical properties northward. In spring, coastal upwelling had commenced and surface flow along the transect presumably became equatorward. As a consequence of these dynamics, in winter the thermocline was deeper, SST was higher, macronutrients, chlorophyll and primary production were low along the entire transect, with most properties lacking strong latitudinal trends. In spring, the thermocline, macronutrients, chlorophyll and primary production rose along the entire section but most dramatically in the north where upwelling was stronger. Prochlorophytes and other small open-ocean phytoplankton were more abundant in winter along the entire transect and to the south in spring, whereas diatoms, a characteristic coastal group of phytoplankton, were more abundant in spring and in the north. Surface iron was higher in the north in winter, but lower there in spring, presumably reflecting drawdown by diatoms. These results are detailed in the figure captionsWe would like to express our gratitude to the David and Lucile Packard Foundation for funding this workN

Towards precision medicine: defining and characterizing adipose tissue dysfunction to identify early immunometabolic risk in symptom-free adults from the GEMM family study

Interactions between macrophages and adipocytes are early molecular factors influencing adipose tissue (AT) dysfunction, resulting in high leptin, low adiponectin circulating levels and low-grade metaflammation, leading to insulin resistance (IR) with increased cardiovascular risk. We report the characterization of AT dysfunction through measurements of the adiponectin/leptin ratio (ALR), the adipo-insulin resistance index (Adipo-IRi), fasting/postprandial (F/P) immunometabolic phenotyping and direct F/P differential gene expression in AT biopsies obtained from symptom-free adults from the GEMM family study. AT dysfunction was evaluated through associations of the ALR with F/P insulin-glucose axis, lipid-lipoprotein metabolism, and inflammatory markers. A relevant pattern of negative associations between decreased ALR and markers of systemic low-grade metaflammation, HOMA, and postprandial cardiovascular risk hyperinsulinemic, triglyceride and GLP-1 curves was found. We also analysed their plasma non-coding microRNAs and shotgun lipidomics profiles finding trends that may reflect a pattern of adipose tissue dysfunction in the fed and fasted state. Direct gene differential expression data showed initial patterns of AT molecular signatures of key immunometabolic genes involved in AT expansion, angiogenic remodelling and immune cell migration. These data reinforce the central, early role of AT dysfunction at the molecular and systemic level in the pathogenesis of IR and immunometabolic disorders

The global burden of trichiasis in 2016.

BACKGROUND: Trichiasis is present when one or more eyelashes touches the eye. Uncorrected, it can cause blindness. Accurate estimates of numbers affected, and their geographical distribution, help guide resource allocation. METHODS: We obtained district-level trichiasis prevalence estimates in adults for 44 endemic and previously-endemic countries. We used (1) the most recent data for a district, if more than one estimate was available; (2) age- and sex-standardized corrections of historic estimates, where raw data were available; (3) historic estimates adjusted using a mean adjustment factor for districts where raw data were unavailable; and (4) expert assessment of available data for districts for which no prevalence estimates were available. FINDINGS: Internally age- and sex-standardized data represented 1,355 districts and contributed 662 thousand cases (95% confidence interval [CI] 324 thousand-1.1 million) to the global total. Age- and sex-standardized district-level prevalence estimates differed from raw estimates by a mean factor of 0.45 (range 0.03-2.28). Previously non- stratified estimates for 398 districts, adjusted by ×0.45, contributed a further 411 thousand cases (95% CI 283-557 thousand). Eight countries retained previous estimates, contributing 848 thousand cases (95% CI 225 thousand-1.7 million). New expert assessments in 14 countries contributed 862 thousand cases (95% CI 228 thousand-1.7 million). The global trichiasis burden in 2016 was 2.8 million cases (95% CI 1.1-5.2 million). INTERPRETATION: The 2016 estimate is lower than previous estimates, probably due to more and better data; scale-up of trichiasis management services; and reductions in incidence due to lower active trachoma prevalence

Renewable energy from Cyanobacteria: energy production optimization by metabolic pathway engineering

The need to develop and improve sustainable energy resources is of eminent importance due to the finite nature of our fossil fuels. This review paper deals with a third generation renewable energy resource which does not compete with our food resources, cyanobacteria. We discuss the current state of the art in developing different types of bioenergy (ethanol, biodiesel, hydrogen, etc.) from cyanobacteria. The major important biochemical pathways in cyanobacteria are highlighted, and the possibility to influence these pathways to improve the production of specific types of energy forms the major part of this review