Climatic variability related to El Niño in Ecuador ? a historical background

International audienceThis paper reports on an investigation into the chronology of El Niño/Southern Oscillation (ENSO) events, during the period from the arrival of conquistadores in Ecuador in 1532 until the year 1900. A number of probable El Niño events and drought years can be dated from anecdotal reports of significant rainfall and drought in the equatorial region. The evidence of ENSO has been documented from early reports in the South America archives. A large number of books and articles have been reviewing from the Ecuadorian archives to obtain information on El Niño events that have occurred over the past centuries. This information is based on evidence obtained from the equatorial region, where strong and very strong El Niño events clearly separate the northern part of the Ecuadorian coast from the southern region, the normally rainy season specially from west-central to the south coast of Ecuador, as well as the drought years, reported in this region which is climatologically and oceanographically different from the moist Northern coast of Ecuador. Given the normal occurrence of rains in the southern coast of Ecuador, it is reasonable to expect that at least some of the major rainy seasons would be recorded in local chronicles and publications. This information has been compared with reports obtained from Peru. Relative strengths of events are based on such considerations as wind and current effects on travel times of ancient sailing ships, degree of physical damage and destruction, amounts of rainfall and flooding, human disease epidemic, mass mortality of endemic marine organism, rises in sea temperatures and sea levels, effects on coastal fisheries. This paper is the first survey of the historical sources concerned the rainfall and drought in Ecuador. In the course of this investigation we also noted some extended periods of time, near decadal or longer over the past records, when the amount and/or strength of El Niño and its resulting effects appeared to represent significant long-term climate changes

Metallochaperones Are Needed for Mycobacterium tuberculosis and Escherichia coli Nicotinamidase-Pyrazinamidase Activity.

Mycobacterium tuberculosis nicotinamidase-pyrazinamidase (PZAse) is a metalloenzyme that catalyzes conversion of nicotinamide-pyrazinamide to nicotinic acid-pyrazinoic acid. This study investigated whether a metallochaperone is required for optimal PZAse activity. M. tuberculosis and Escherichia coli PZAses (PZAse-MT and PZAse-EC, respectively) were inactivated by metal depletion (giving PZAse-MT-Apo and PZAse-EC-Apo). Reactivation with the E. coli metallochaperone ZnuA or Rv2059 (the M. tuberculosis analog) was measured. This was repeated following proteolytic and thermal treatment of ZnuA and Rv2059. The CDC1551 M. tuberculosis reference strain had the Rv2059 coding gene knocked out, and PZA susceptibility and the pyrazinoic acid (POA) efflux rate were measured. ZnuA (200 μM) achieved 65% PZAse-EC-Apo reactivation. Rv2059 (1 μM) and ZnuA (1 μM) achieved 69% and 34.3% PZAse-MT-Apo reactivation, respectively. Proteolytic treatment of ZnuA and Rv2059 and application of three (but not one) thermal shocks to ZnuA significantly reduced the capacity to reactivate PZAse-MT-Apo. An M. tuberculosis Rv2059 knockout strain was Wayne positive and susceptible to PZA and did not have a significantly different POA efflux rate than the reference strain, although a trend toward a lower efflux rate was observed after knockout. The metallochaperone Rv2059 restored the activity of metal-depleted PZAse in vitro Although Rv2059 is important in vitro, it seems to have a smaller effect on PZA susceptibility in vivo. It may be important to mechanisms of action and resistance to pyrazinamide in M. tuberculosis Further studies are needed for confirmation.IMPORTANCE Tuberculosis is an infectious disease caused by the bacterium Mycobacterium tuberculosis and remains one of the major causes of disease and death worldwide. Pyrazinamide is a key drug used in the treatment of tuberculosis, yet its mechanism of action is not fully understood, and testing strains of M. tuberculosis for pyrazinamide resistance is not easy with the tools that are presently available. The significance of the present research is that a metallochaperone-like protein may be crucial to pyrazinamide's mechanisms of action and of resistance. This may support the development of improved tools to detect pyrazinamide resistance, which would have significant implications for the clinical management of patients with tuberculosis: drug regimens that are appropriately tailored to the resistance profile of a patient's individual strain lead to better clinical outcomes, reduced onward transmission of infection, and reduction of the development of resistant strains that are more challenging and expensive to treat

Motif effects in Affymetrix GeneChips seriously affect probe intensities

An Affymetrix GeneChip consists of an array of hundreds of thousands of probes (each a sequence of 25 bases) with the probe values being used to infer the extent to which genes are expressed in the biological material under investigation. In this article, we demonstrate that these probe values are also strongly influenced by their precise base sequence. We use data from >28 000 CEL files relating to 10 different Affymetrix GeneChip platforms and involving nearly 1000 experiments. Our results confirm known effects (those due to the T7-primer and the formation of G-quadruplexes) but reveal other effects. We show that there can be huge variations from one experiment to another, and that there may also be sizeable disparities between batches within an experiment and between CEL files within a batch. © 2012 The Author(s)

Calidad nutricional de los rebrotes de un pajonal de pasto puna (Amelichloa brachychaeta) sometido a pastoreo con altas cargas instantáneas

Las áreas cubiertas por vegetación natural han tenido en la Argentina gran importancia para la actividad ganadera. El pastoreo selectivo ha provocado la transformación de estos pastizales en pajonales. En la región semiárida central de la Argentina muchos son dominados por pasto puna (Amelichloa brachychaeta), cuya estrategia de dispersión hace muy difícil su manejo. El pastoreo es uno de los factores que posee mayor influencia sobre la estructura y dinámica de los pastizales y podría ser utilizado como un disturbio que genere el rebrote y permita la posterior utilización de estas especies. Entonces, una de las posibilidades de manejo sería someter estos “pajonales” a una extracción permanente que debilitaría estas especies disminuyendo la competencia y el exceso de cobertura para facilitar la germinación y establecimiento de las especies forrajeras. Para ello, aún falta conocer la respuesta de A. brachychaeta a altas presiones instantáneas y frecuentes de pastoreo y la calidad nutricional de los rebrotes. Los objetivos fueron: evaluar la cantidad y calidad de la fitomasa aérea proveniente de rebrotes de un pajonal sometido a distintas presiones de pastoreo. En un área dominada por pasto puna, se realizó un ensayo de pastoreo con distintas cargas ganaderas (Fig. 1 a y b). Previo a cada pastoreo se colectó material vegetal (rebrotes de especies no forrajeras y forrajeras) que fue pesado y acondicionado para realizar las determinaciones de calidad. Se establecieron ocho parcelas de 50x100 m en las que se establecieron cuatro tratamientos de carga (4, 6, 10 y 14 animales.ha-1) con dos réplicas cada uno. Se realizó un pastoreo de homogeneización y cuatro pastoreos durante el período 08/2016-09/2017. En cuanto a la calidad nutricional se realizaron análisis de FDN, FDA y PB. Las bajas cargas favorecieron la selección de especies forrajeras. Con la carga más alta se observó una disminución en la producción de rebrotes de todas las especies, incluso las no forrajeras. Con las cargas intermedias se obtuvo la mayor fitomasa acumulada durante el año (1536 y 1355 KgMS.ha-1 para 6 y 10 animales.ha-1 respectivamente) y el mejor control del pajonal sin afectar el estado de los animales. Respecto a la calidad nutricional, en todos los tratamientos se observaron mayores contenidos de FDN y FDA en los rebrotes de Amelichloa brachychaeta y los mayores contenidos de PB en las especies forrajeras. Un pastoreo de limpieza con muy alta carga realizado a principios de la primavera y sucesivos pastoreos durante cortos períodos de tiempo (en la medida que se generen rebrotes), provocará que la fitomasa disponible sea siempre de mayor valor nutricional y de esta manera se evita el envejecimiento y pérdida de calidad del material proveniente de las especies no forrajeras. A partir de estos resultados, se observa que tanto la producción de fitomasa aérea provista por los rebrotes del pastizal (incluyendo los provenientes de A. brachychaeta) (Fig. 1 c), como su calidad nutricional constituyen un recurso interesante para la producción ganadera de la región. Así, todo depende de la estrategia de manejo adoptada y de una planificación acorde al estado fenológico de las especies dominantes

Child Injuries and the Timing of SNAP Benefits Receipt

The Supplemental Nutrition Assistance Program (SNAP) is an important federal resource that provides nutritional assistance to low-income families. Timing of SNAP benefits can reduce childhood injuries