Organized Disassembly of Photosynthesis During Programmed Cell Death Mediated By Long Chain Bases.

In plants, pathogen triggered programmed cell death (PCD) is frequently mediated by polar lipid molecules referred as long chain bases (LCBs) or ceramides. PCD interceded by LCBs is a well-organized process where several cell organelles play important roles. In fact, light-dependent reactions in the chloroplast have been proposed as major players during PCD, however, the functional aspects of the chloroplast during PCD are largely unknown. For this reason, we investigated events that lead to disassembly of the chloroplast during PCD mediated by LCBs. To do so, LCB elevation was induced with Pseudomonas syringae pv. tomato (a non-host pathogen) or Fumonisin B1 in Phaseolus vulgaris. Then, we performed biochemical tests to detect PCD triggering events (phytosphingosine rises, MPK activation and H2O2 generation) followed by chloroplast structural and functional tests. Observations of the chloroplast, via optical phenotyping methods combined with microscopy, indicated that the loss of photosynthetic linear electron transport coincides with the organized ultrastructure disassembly. In addition, structural changes occurred in parallel with accumulation of H2O2 inside the chloroplast. These features revealed the collapse of chloroplast integrity and function as a mechanism leading to the irreversible execution of the PCD promoted by LCBs

Fundamental contributions to the technological development of advanced carbon materials from Coal Tar

La brea generada a partir de alquitrán de hulla constituye un precursor de bajo coste, de materiales avanzados de carbono de excelentes prestaciones mecánicas debido a su alto rendimiento en carbono con estructura grafítica derivado de su alto grado de aromaticidad. En este artículo se revisan las contribuciones que han dado impulso al desarrollo tecnológico de los materiales avanzados de carbono obtenidos a partir de alquitrán de hulla. Se analiza el efecto de las condiciones experimentales, de cada una de las etapas de síntesis, sobre los parámetros característicos de la materia en las diferentes fases de procesamiento que incluyen la coquización del carbón, la destilación del alquitrán, la pirólisis de la brea y la carbonización de la mesofase.Abstract: Pitch generated from the coal tar is a low cost precursor of advanced carbon materials with excellent mechanical properties due to its high carbon yield with graphitic structure derived from its high degree of aromaticity. This article reviews the contributions that have given impetus to the technological development of advanced carbon materials derived from coal tar. Analyze the effect of experimental conditions, each of the synthesis steps, on the characteristic parameters of the material in the different processing stages including the coking of coal, tar distillation, pyrolysis of tar and carbonization of mesophase

Kinetic study of Arsenic removal in a filter press type electrochemical reactor

El arsénico (As) es un elemento ampliamente distribuido en la naturaleza y de elevada toxicidad para los seres vivos. La presencia de arsénico en el agua subterránea (AN) utilizada para bebida humana o animal es uno de los problemas sanitarios más importantes a nivel mundial. Sin embargo, las poblaciones más afectadas viven en áreas rurales donde la problemática se ve agravada por factores desfavorables de orden socioeconómico, culturales y sanitarios. El AN en diversas áreas de La Comarca Lagunera (México) presenta concentraciones de As superiores a la norma establecida por la Organización Mundial de la Salud (OMS) para agua de bebida (10 mg L-1). Este hecho es muy importante ya que los acuíferos constituyen la principal fuente de abastecimiento a la población. En consecuencia, una amplia gama de tratamientos ha sido desarrollada para remover arsénico de agua modelo (AM) y natural subterránea (AN). Sin embargo, entre ellos, el proceso de electrocoagulación (EC) presenta ventajas importantes sobre los otros procesos debido a que es un método eficiente para el tratamiento de una gran variedad de aguas naturales y residuales. El equipo requerido es compacto y fácil de operar, el proceso evita el uso de reactivos, y por lo tanto no se presentan problemas de neutralización por exceso de químicos evitando que se de una contaminación secundaria. Por esta razón, en este trabajo la remoción de arsénico del agua modelo (AM) y del agua natural subterránea (AN) extraída de la Comarca Lagunera, fue llevada a cabo por el proceso EC. Los experimentos fueron desarrollados inicialmente en un reactor electroquímico filtro prensa tipo batch. De los resultados obtenidos en el reactor, se encontró que la eficiencia de remoción de arsénico se logra a un tiempo de tratamiento inferior de 10 min operado a una densidad de corriente de 15 A m-2 y un flujo volumétrico de 7.64 L min-1.Abstract: Arsenic (As) is a widely distributed element in nature, and is highly toxic for living beings. The presence of arsenic in underground water (GW) used for human or animal consumption is one of the most important sanitation problems at a global level. However, most of the communities that are affected are usually in rural areas, where the problem is worsened by unfavorable socioeconomic, cultural and sanitation factors. The GW in different areas of La Comarca Lagunera (México) presents As concentrations that are above the standard established by World Health Organization (WHO) for drinking water (10 mgL-1). This is an important fact because aquifers are the main supply source for many populated areas. By consequence, a variety of treatment processes have been developed for arsenic removal from model water (MW) and underground water (GW). Nevertheless, among them, the electrocoagulation (EC) process presents important advantages over others due to the low sludge amount produced and the lack of chemical reagents needed, consequently, there is no problem of neutralizing excess chemicals and no possibility of secondary pollution. Moreover, it is an efficient method for the treatment of many natural waters and wastewaters. The equipment required is compact and easy to operate. For this reason, in this work the removal of As from underground water (GW) extracted from La Comarca Lagunera, was performed by the electrocoagulation EC process. Experiments were developed in a batch electrochemical reactor type filter press. According to results obtained in these four reactors, the highest As removal efficiency was achieved at the shortest treatment time (10 min), employing the reactor at a current density value of 15 A m-2 and flow rate of 7.64 L min-1

Cu2ZnSnS4 thin film solar cells grown by fast thermal evaporation and thermal treatment

Cu2ZnSnS4 thin films have been produced via rapid thermal evaporation of off-stoichiometric kesterite powder followed by annealing in an Ar atmosphere. Different heating rates were applied during the thermal treatments. The chemical composition and structural properties of the deposited layers as well as the distribution of the elements through the kesterite thin film have been investigated. The initial growth of a SnS secondary phase during evaporation led to the formation of this secondary phase next to the Mo back contact. Solar cell power conversion efficiencies were limited to values about 3 % due to this secondary phase. Furthermore, an increased open circuit voltage was demonstrated by using a Zn(O,S) buffer layerThis work was supported by DAAD project (INTERKEST, Ref: 57050358), Marie Curie-ITN (KESTCELLS, GA: 316488) and MINECO project (SUNBEAM, ENE2013-49136-C4-3-R). RC and ES acknowledge financial support from Spanish MINECO within the Ramón y Cajal program (RYC-2011-08521) and (RYC-2011-09212) respectively. SG also thanks the Government of Spain for the FPI fellowship (BES-2014-068533)

Mutations related to Antiretroviral Resistance identified by ultra-deep sequencing in HIV-1 infected children under Structured Interruptions of HAART

Altres ajuts: CONACYT/GCPS/44519Although Structured Treatment Interruptions (STI) are currently not considered an alternative strategy for antiretroviral treatment, their true benefits and limitations have not been fully established. Some studies suggest the possibility of improving the quality of life of patients with this strategy; however, the information that has been obtained corresponds mostly to studies conducted in adults, with a lack of knowledge about its impact on children. Furthermore, mutations associated with antiretroviral resistance could be selected due to sub-therapeutic levels of HAART at each interruption period. Genotyping methods to determine the resistance profiles of the infecting viruses have become increasingly important for the management of patients under STI, thus low-abundance antiretroviral drug-resistant mutations (DRM's) at levels under limit of detection of conventional genotyping (<20% of quasispecies) could increase the risk of virologic failure. In this work, we analyzed the protease and reverse transcriptase regions of the pol gene by ultra-deep sequencing in pediatric patients under STI with the aim of determining the presence of high- and low-abundance DRM's in the viral rebounds generated by the STI. High-abundance mutations in protease and high- and low-abundance mutations in reverse transcriptase were detected but no one of these are directly associated with resistance to antiretroviral drugs. The results could suggest that the evaluated STI program is virologically safe, but strict and carefully planned studies, with greater numbers of patients and interruption/restart cycles, are still needed to evaluate the selection of DRM's during STI

Geology of La Reforma caldera complex, Baja California, Mexico

A new geological map at 1:50,000 scale of La Reforma Caldera Complex has been produced applying modern survey methodologies to volcanic areas. This map aims to represent a reliable and objective tool to understand the geological evolution of the region. La Reforma Caldera Complex is a Pleistocene nested caldera located in the central part of the Baja California peninsula, Mexico. The twelve formations defined within the Quaternary volcanic record were grouped into three phases (pre-caldera, caldera, and post-caldera). The pre-caldera phase (>1.35 Ma) is characterized by scattered eruptions, mostly occurred in submarine environment. The caldera phase (1.35–0.96 Ma) groups several distinct explosive and effusive eruptions that formed the present-day caldera depression. The post caldera phase includes scattered effusive eruptions (ended at 0.28 Ma) and resurgence, characterized by several hundred meters of uplift of the central block within the caldera depression

Mayonesas y aderezos adicionados con extracto de jamaica (Hibiscus sabdariffa L.)

La jamaica (Hibiscus sabdariffa L.) es una especie vegetal que destaca por sus propiedades medicinales como reducir el colesterol y disminuir la presión arterial. En México se cosechan 18 mil hectáreas de jamaica con un rendimiento promedio de 265 kg/ha. Posee una gran cantidad de antioxidantes, principalmente antocianinas. El objetivo de este trabajo fue emplear el extracto de Jamaica para la elaboración de mayonesas y aderezos con un valor agregado. Se elaboraron tres formulaciones: MCtrl (73% de aceite y 0% de extracto), MJ1 (64.15% de aceite y 20% de extracto) y ADJ2 (54.15% de aceite y 30% de extracto) a las cuales se les midió el tamaño de partícula, y para las formulaciones MJ1 y ADJ2 se realizó una descripción organoléptica. Los resultados de tamaño de partícula indicaron que la formulación ADJ2 es la más estable. En la prueba hedónica el 66.67% de los jueces dijo que les disgustaba ligeramente las formulación MJ1, y el 33.33% que le gustaba ligeramente. Por lo que en base a estos resultados hay que disminuir el sabor ácido que aporta el extracto de jamaica a las formulaciones empleando algún saborizante

Blanqueo de la fibra de celulosa de paja de caña de azúcar (Saccharum spp.) con peróxido de hidrógeno

Objective: Optimize the treatment of cellulose bleaching, replacing the use of sodium hypochlorite with hydrogen peroxide. Design/methodology/approach: A completely randomized design was used, the treatments were six processes of cellulose bleaching, which were carried out with 18 repetitions. To extract the cellulose, the artisanal method and 40 g of straw were used per treatment. The extraction and yield of cellulose and cellulose fiber, whiteness, crystallinity, granule size, purity of the cellulose and an economic analysis of the cost of the bleaching process were evaluated. Results: The average cellulose fiber extracted was 14 g, meaning that the yield of cellulose fiber was 35%. The average cellulose was 8 g, which represents a yield of 39.9% cellulose. The whiteness with sodium hypochlorite was 86.6 %, with a crystallinity of 65.9% and the cellulose granule size was 2.6 nm, and with hydrogen peroxide whiteness was 83%, the crystallinity was 68 % and the average granule size was 2.7 nm, according to the XRD method. This means similarity in both bleaching process. According to the FTIR analysis, the cellulose bleached in both processes is similar to the cellulose structure. Limitations on study/implications: Cellulose bleaching is more expensive with hydrogen peroxide process. Findings/conclusions: The cellulose extracted from the sugar cane straw, bleached with hydrogen peroxide presents acceptable characteristics to produce artisanal paperObjetivo: Optimizar el tratamiento de blanqueo de celulosa, sustituyendo el uso de hipoclorito de sodio por peróxido de hidrógeno. Diseño/metodología/aproximación: Se utilizó un diseño completamente al azar, donde los tratamientos fueron seis procesos de blanqueo de celulosa, que se realizaron con 18 repeticiones. Para extraer la celulosa se usó el método artesanal y 40 g de paja por tratamiento. Se evaluó la extracción y rendimiento de fibra de celulosa y celulosa, blancura, cristalinidad, tamaño de gránulo, pureza de la celulosa y un análisis económico del costo del proceso de blanqueo. Resultados: El promedio de fibra de celulosa extraída fue de 14 g, esto significa que el rendimiento de fibra de celulosa fue 35 %. El promedio de celulosa fue de 8 g que representa un rendimiento de 39.9 % de celulosa. La blancura con hipoclorito de sodio fue del 86.6%, la cristalinidad de 65.9 % y un tamaño de granulo de celulosa de 2.6 nm, y con peróxido de hidrógeno fue del 83 %, la cristalinidad del 68% y el tamaño de granulo promedio fue 2.7 nm, según el método de XRD, indicando resultados similares. De acuerdo al análisis de FTIR, la celulosa blanqueada en ambos procesos, es similar a la estructura de celulosa reportada en la literatura. Limitaciones del estudio/implicaciones: Se observó un costo más elevado en el blanqueo de la celulosa con el peróxido de hidrógeno. Hallazgos/conclusiones: La celulosa de la paja de caña de azúcar blanqueada con peróxido de hidrógeno presenta características adecuadas para elaborar papel artesanal

DNA vaccine encoding human papillomavirus antigens flanked by a signal peptide and a KDEL sequence induces a potent therapeutic antitumor effect

Abstract. Cellular immune responses play a critical role in the eradication of intracellular infections and malignant cells through the recognition and subsequent removal of the infection or malignant cells. Effective antigen presentation is crucial for stimulating the immune system against malignant cells. Calreticulin (CRT) has been used to improve antigen presentation. However, CRT overexpression has been previously associated with the development of pancreatic and breast cancer. The import and retention signals of CRT in the endoplasmic reticulum (ER) can be used to overcome CRT overexpression. The present study describes the potent antitumor effect of a DNA vaccine encoding human papillomavirus type 16 E6 and E7 antigens flanked by ER import and retention signals (SP-E6E7m-KDEL). The effect of this vaccine was compared with that of E6 and E7 antigens fused to human full-length CRT (hCRT-E6E7m). In the present study, the effectiveness of SP-E6E7m-KDEL for inducing an interferon-γ antigen‑specific, response and its therapeutic effect against tumors was demonstrated, which was as effective as immunization against those antigens fused to CRT. This simplified strategy, using ER import and retention signal peptides to direct antigens to this organelle, provides an efficient alternative to traditional vaccines and, more importantly, a safe and potent system to induce a therapeutic antitumor response