Cross-talk between signaling pathways: The link between plant secondary metabolite production and wounding stress response

Plants subjected to wounding stress produce secondary metabolites. Several of these metabolites prevent chronic diseases and can be used as colorants, flavors, and as antimicrobials. This wound-induced production of plant secondary metabolites is mediated by signaling-molecules such as reactive oxygen species (ROS), ethylene (ET) and jasmonic acid (JA). However, their specific role and interactions that modulate the wound-respond in plants is not fully understood. In the present study, a subtractive cDNA library was generated, to better understand the global response of plants to wounding stress. Carrot (Daucus carota) was used as a model system for this study. A total of 335 unique expressed sequence tags (ESTs) sequences were obtained. ESTs sequences with a putative identity showed involvement in stress-signaling pathways as well as on the primary and secondary metabolism. Inhibitors of ROS biosynthesis, ET action, and JA biosynthesis alone and in combination were applied to wounded-carrots in order to determine, based on relative gene expression data, the regulatory role of ET, JA, and ROS on the wound-response in plants. Our results demonstrate that ROS play a key role as signaling-molecules for the wound-induced activation of the primary and secondary metabolism whereas ET and JA are essential to modulate ROS levels

Sensibilidad de dos serovariedades de leptospira interrogans a diferentes concentraciones de 5-fluorouracilo.

Uno de los principales problemas en el aislamiento de Leptospira a partir de muestras de campo es su alta contaminación por diversos grupos bacterianos, lo cual hace imprescindible el uso de inhibidores, tales como el 5Fluorouracilo (5-FU)

The roles of histone post-translational modifications in the formation and function of a mitotic chromosome

During mitosis, many cellular structures are organized to segregate the replicated genome to the daughter cells. Chromatin is condensed to shape a mitotic chromosome. A multiprotein complex known as kinetochore is organized on a specific region of each chromosome, the centromere, which is defined by the presence of a histone H3 variant called CENP-A. The cytoskeleton is re-arranged to give rise to the mitotic spindle that binds to kinetochores and leads to the movement of chromosomes. How chromatin regulates different activities during mitosis is not well known. The role of histone post-translational modifications (HPTMs) in mitosis has been recently revealed. Specific HPTMs participate in local compaction during chromosome condensation. On the other hand, HPTMs are involved in CENP-A incorporation in the centromere region, an essential activity to maintain centromere identity. HPTMs also participate in the formation of regulatory protein complexes, such as the chromosomal passenger complex (CPC) and the spindle assembly checkpoint (SAC). Finally, we discuss how HPTMs can be modified by environmental factors and the possible consequences on chromosome segregation and genome stability

Plants as Biofactories: Postharvest Stress-Induced Accumulation of Phenolic Compounds and Glucosinolates in Broccoli Subjected to Wounding Stress and Exogenous Phytohormones

Broccoli contains high levels of bioactive molecules and is considered a functional food. In this study, postharvest treatments to enhance the concentration of glucosinolates and phenolic compounds were evaluated. Broccoli whole heads were wounded to obtain florets and wounded florets (florets cut into four even pieces) and stored for 24 h at 20 ºC with or without exogenous ethylene (ET, 1000 ppm) or methyl jasmonate (MeJA, 250 ppm). Whole heads were used as a control for wounding treatments. Regarding glucosinolate accumulation, ET selectively induced the 4-hydroxylation of glucobrassicin in whole heads, resulting in ~223% higher 4-hydroxyglucobrassicin than time 0 h samples. Additionally, glucoraphanin was increased by ~53% in whole heads treated with ET, while neoglucobrassicin was greatly accumulated in wounded florets treated with ET or MeJA, showing increases of ~193% and ~286%, respectively. On the other hand, although only whole heads stored without phytohormones showed higher concentrations of phenolic compounds, which was reflected in ~33%, ~30%, and 46% higher levels of 1,2,2-trisinapoylgentiobose, 1,2-diferulolylgentiobiose, and 1,2-disinapoyl-2-ferulolylgentiobiose, respectively; broccoli florets stored under air control conditions showed enhanced concentrations of 3-O-caffeoylquinic acid, 1,2-disinapoylgentiobiose, and 1,2-disinapoyl-2-ferulolylgentiobiose (~22%, ~185%, and ~65% more, respectively). However, exogenous ET and MeJA impeded individual phenolics accumulation. Results allowed the elucidation of simple and effective postharvest treatment to enhance the content of individual glucosinolates and phenolic compounds in broccoli. The stressed-broccoli tissue could be subjected to downstream processing in order to extract and purify bioactive molecules with applications in the dietary supplements, agrochemical and cosmetics markets

Soliton Steering by Longitudinal Modulation of the Nonlinearity in Waveguide Arrays

We show how discrete solitary waves in one and two-dimensional waveguide arrays can be steered across the lattice via the introduction of a longitudinal periodic modulation of the nonlinear response. Through parametric energy transfer from the modulation to the solitary wave, the latter can increase its width and overcome the Peierls-Nabarro potential to propagate freely

Características clínicas y factores de riesgo para mortalidad durante la ‘Primera Ola’ de COVID-19 en Reynosa, Tamaulipas

To describe the clinical characteristics of patients with COVID-19 in Reynosa, Tamaulipas during 2020 and to identify the risk factors for mortality. Material and methods: The COVID-19 cases registered from March to November 2020 in Reynosa were divided into survivors and non-survivors. Data were analyzed using χ2 tests, Mann-Whitney tests, principal component analysis, and Cox’s regression. Results: The highest number of COVID-19 cases and deaths was observed in July, in men between 36-40 years old. The most frequent symptoms (37-51%) were headache, fever, cough, myalgia, and arthralgia. Clinical characteristics between survivors and non-survivors were significant (P<0.05) in all cases, except for age (21-40 years), COVID-19 contact, and history of asthma. Age, gender (men), diabetes, hypertension, heart disease, COPD, and chronic kidney disease (CKD) were associated with risk of death from COVID-19 (P<0.05). The highest fatality rates happened in patients over 80 years of age, ICU admission, or need for intubation (P<0.0001). Conclusions: The most frequent symptoms in COVID-19 patients in Reynosa during 2020 were headache, fever, cough, myalgia, and arthralgia. Age, gender, diabetes, hypertension, heart disease, COPD, and CKD increase mortality. The factors with the highest mortality risk were age over 80 years, admitted to the icu or intubated.Describir las características clínicas de pacientes con COVID-19 en Reynosa, Tamaulipas en el 2020 e identificar factores de riesgo para mortalidad. Material y métodos: Los casos COVID-19 registrados de marzo a noviembre de 2020 en Reynosa se dividieron en supervivientes y no supervivientes. Los datos se analizaron mediante pruebas de χ2 y Mann-Whitney, análisis de componentes principales y regresión de Cox. Resultados: El mayor número de casos COVID-19 y de decesos se observó en julio, en hombres de 36-40 años. Los síntomas más frecuentes (37-51%) fueron cefalea, fiebre, tos, mialgia y artralgia. Las características clínicas entre sobrevivientes y no sobrevivientes fueron significativas (P<0.05) en todos los casos, excepto para edad (21-40 años), contacto COVID-19 y antecedentes de asma. La edad, el género (hombres), diabetes, hta, cardiopatías, copd, epoc y enfermedad crónica del riñón (ecr) se asociaron con riesgo de muerte por COVID-19 (P<0.05). La mayor mortalidad ocurrió con más de 80 años, ingreso a uci o necesidad de intubación (P<0.0001). Conclusiones: Los síntomas más frecuentes en pacientes COVID-19 de Reynosa durante 2020 fueron cefalea, fiebre, tos, mialgia y artralgia. La edad, género, diabetes, hta, cardiopatías, copd, epoc y ecr incrementaron la mortalidad. La mayor mortalidad se observó con más de 80 años, internados en uci o intubados

Methylation of subtelomeric chromatin modifies the expression of the lncRNA TERRA, disturbing telomere homeostasis

The long noncoding RNA (lncRNA) telomeric repeat-containing RNA (TERRA) has been associated with telomeric homeostasis, telomerase recruitment, and the process of chromosome healing; nevertheless, the impact of this association has not been investigated during the carcinogenic process. Determining whether changes in TERRA expression are a cause or a consequence of cell transformation is a complex task because studies are usually carried out using either cancerous cells or tumor samples. To determine the role of this lncRNA in cellular aging and chromosome healing, we evaluated telomeric integrity and TERRA expression during the establishment of a clone of untransformed myeloid cells. We found that reduced expression of TERRA disturbed the telomeric homeostasis of certain loci, but the expression of the lncRNA was affected only when the methylation of subtelomeric bivalent chromatin domains was compromised. We conclude that the disruption in TERRA homeostasis is a consequence of cellular transformation and that changes in its expression profile can lead to telomeric and genomic instability