On the discrete Peyrard-Bishop model of DNA: stationary solutions and stability

As a first step in the search of an analytical study of mechanical denaturation of DNA in terms of the sequence, we study stable, stationary solutions in the discrete, finite and homogeneous Peyrard-Bishop DNA model. We find and classify all the stationary solutions of the model, as well as analytic approximations of them, both in the continuum and in the discrete limits. Our results explain the structure of the solutions reported by Theodorakopoulos {\em et al.} [Phys. Rev. Lett. {\bf 93}, 258101 (2004)] and provide a way to proceed to the analysis of the generalized version of the model incorporating the genetic information.Comment: 15 pages, 12 figure

WHI-2 Regulates Intercellular Communication via a MAP Kinase Signaling Complex

he formation of the fungal mycelial network is facilitated by somatic cell fusion of germinating asexual spores (or germlings). Neurospora crassa germlings in close proximity display chemotropic growth that is dependent upon an intracellular network of mitogen-activated protein kinase (MAPK) signaling cascades. Approximately 80 genes involved in intercellular communication and fusion have been identified, including three mutants with similar morphological phenotypes: Δwhi-2, Δcsp-6, and Δamph-1. Here we show that WHI-2 localizes to the cell periphery and regulates endocytosis, mitochondrial organization, sporulation, and cell fusion. WHI-2 was required to transduce signals through a conserved MAPK pathway (NRC-1/MEK-2/MAK-2) and target transcription factors (PP-1/ADV-1). The amph-1 locus encodes a Bin/Amphiphysin/Rvs domain-containing protein and mis-expression of whi-2 compensated for the cell fusion and endocytosis deficiencies of a Δamph-1 mutant. The csp-6 locus encodes a haloacid dehalogenase phosphatase whose activity was essential for cell fusion. Although fusion-deficient with themselves, cells that lacked whi-2, csp-6, or amph-1 showed a low frequency of chemotropic interactions with wild type cells. We hypothesize that WHI-2 could be important for signal perception during chemotropic interactions via a role in endocytosis

Kink dynamics in spatially inhomogeneous media: the role of internal modes

The phenomenon of length-scale competition in soliton-bearing equations perturbed by spatially dependent terms A. Sánchez and A. R. Bishop, SIAM Rev. 40, 579 1998 is analyzed from a general viewpoint. We show that the perturbation gives rise to an effective potential for solitons, which consists of wells and barriers. We calculate the effect of these potential features on the solitons, establishing a direct relationship between the maxima, minima, and curvature of the potential with soliton deformations. When the typical wavelength of the perturbation is of the order of the soliton width, these deformations are seen to correspond to the excitation of shape modes and can lead to the dissipation of the soliton kinetic energy and, further, to the impossibility of soliton propagation. Thus, we demonstrate that the mechanism for length-scale competition is related to changes in the dynamics of the internal modes. We study different examples where the perturbation is introduced parametrically and nonparametrically to make it clear that our results apply to a wide class of equations.This work was supported by MEC Spain under Grants MOSAICO and No. NAN2004-9087-C03-03 and by the Comunidad Autónoma de Madrid (Spain) under Grants No. UC3M-FI-05-007 and SIMUMAT-CM. The work by J.G. was done in part during a stay at Universidad Carlos III de Madrid, whose financial support is acknowledged, and S.C. is supported by the Consejería de Educación de la Comunidad Autónoma de Madrid and the Fondo Social Europeo.Publicad

A Nori but not a Konbu, dietary supplement decreases the cholesterolaemia, liver fat infiltration and mineral bioavailability in hypercholesterolaemic growing Wistar rats

The nutritional consequences of algae consumption in young populations consuming hypercholesterolaemic diets have hardly been investigated. This study tests the effect of algae supplementation of cholesterol-enriched balanced diets on growth, dietary efficiency ratio, mineral intake and absorption, organ weight and structure and cholesterolaemia in growing Wistar rats. Three groups of ten rats each were fed for 3 weeks with experimental diets containing 93% casein-soyabean oil base with 2.4% cholesterol-raising agent and 7% supplement. The control group received cellulose (35%), group 2 consumed Nori (33.8% fibre) and group 3 consumed Konbu (36.1% fibre). Food intake and body weight gain were not significantly affected. Algae groups presented significantly higher dietary efficiency ratio values than control rats. Apparent absorption of several minerals appeared significantly affected, mainly in Nori-fed rats, with a significant decrease in the ratio of Zn and Cu intakes and apparent absorption. Nori diet significantly decreased plasma cholesterol. Algae supplement did not significantly affect organ size and structure. Control and Konbu rats showed severe liver fat infiltration, while Nori rats exhibited a significantly lower degree of lipid-like hepatocyte vacuolization but light to moderate leukocyte infiltration. Light to moderate scaling off of the epithelium and moderate submucosa oedema was observed in all groups. Although long-term studies are needed to check the possible extrapolation of these data to human subjects, it can be concluded that a Nori, but not a Konbu, dietary supplement reverses the negative effect of dietary cholesterol intake and also appears to be related to mineral availability in growing subjects. © 2007 The Authors.This work was granted by the Spanish Ministerio de Investigación y Ciencia, Project AGL 2005-07204-C02-C1/ALI.Peer Reviewe

Down-regulation of a pectin acetylesterase gene modifies strawberry fruit cell wall pectin stracture and increases fruit firmness

Antisense-mediated down-regulation of several fruit-specific genes has previously demonstrated how the cell wall disassembly in strawberry fruit is mediated by a series of enzymes that act sequentially (Posé et al. 2011). An interesting example, the silencing of the polygalacturonase gene FaPG1, was also related with a significant increase of the post-harvest strawberry fruit firmness (Posé et al. 2013). Our research group has isolated a pectin acetylesterase gene, FaPAE1, which expression is enhanced during strawberry ripening. The main goal of this work was to elucidate the role of the degree of acetylation in cell wall integrity and fruit firmness through the antisense-mediated down-regulation of FaPAE1 in strawberry plants. Several transgenics lines were generated and 5 of them produced fruits 5-15% firmer than controls. Cell wall from ripe fruits was isolated from two independent transgenic lines and a control line, and sequentially extracted with different solvents (PAW, H2O, CDTA, Na2CO3). Modifications in fraction yield, its sugar composition and the degree of acetylation in each fraction were determined. Higher amounts of CDTA and Na2CO3 fractions were obtained in transgenic fruits, suggesting a decreased pectin solubilization as results of FaPAE1 silencing. Accordingly, the degree of acetylation of the Na2CO3-soluble pectins was greater in the transgenic lines than the control, but the opposite result was found in pectins from the CDTA fraction. These results suggest that PAE is preferentially active in pectis that are tightly bound to the cellulose-hemicellulose network and its activity could reduce the complexity of the cell wall structure, allowing that other hydrolytic enzymes could access the pectin chains. Thus, the increased fruit firmness observed in the transgenic FaPAE1 lines could be attributed to the direct effect of the silencing of the PAE enzyme and also to the indirect effect that the increase of the degree of acetylation of pectins has on the activity of other enzymes involved in the cell wall degradation. * Posé et al. (2011). Genes, Genomes and Genomics, 5 (Special Issue 1):40-48 * Posé et al. (2013). Plant Physiology, 150: 1022-1032 We acknowledge support from the Spanish Ministry of Economy and competitivity and Feder EU Funds (grant reference AGL2011-24814), FPI fellowships support for SP (BES-2006-13626) and CP (BES-2009027985), and grant "Ramón y Cajal" support for AJMA (RYC-2011-08839).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Pigment Epithelium Macroadenoma Mimicking Iris or Ciliary Body Melanoma

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Genomic analyses of microdissected Hodgkin and Reed-Sternberg cells: mutations in epigenetic regulators and p53 are frequent in refractory classic Hodgkin lymphoma

This work was supported by grants from the Plan Nacional de I + D + I cofinanced by the ISCIII-Subdirección General de Evaluación and the Fondo Europeo de Desarrollo Regional (FEDER), PI12/1832, the Spanish Association for Cancer Research (AECC), and Programas para Grupos de Investigación de la Comunidad Autónoma de Madrid (Biomedicina 2017)

Combined use of smartphone and smartband technology in the improvement of lifestyles in the adult population over 65 years: study protocol for a randomized clinical trial (EVIDENT-Age study)

Background The increasing use of smartphones by older adults also increases their potential for improving different aspects of health in this population. Some studies have shown promising results in the improvement of cognitive performance through lifestyle modification. All this may have a broad impact on the quality of life and carrying out daily living activities. The objective of this study is to evaluate the effectiveness of combining the use of smartphone and smartband technology for 3 months with brief counseling on life habits, as opposed to providing counseling only, in increasing physical activity and improving adherence to the Mediterranean diet. Secondary objectives are to assess the effect of the intervention on body composition, quality of life, independence in daily living activities and cognitive performance. Methods This study is a two-arm cluster-randomized trial that will be carried out in urban health centers in Spain. We will recruit 160 people aged between 65 and 80 without cardiovascular disease or cognitive impairment (score in the Mini-mental State Examination ≥24). On a visit to their center, intervention group participants will be instructed to use a smartphone application for a period of 3 months. This application integrates information on physical activity received from a fitness bracelet and self-reported information on the patient’s daily nutritional composition. The primary outcome will be the change in the number of steps measured by accelerometer. Secondary variables will be adherence to the Mediterranean diet, sitting time, body composition, quality of life, independence in daily living activities and cognitive performance. All variables will be measured at baseline and on the assessment visit after 3 months. A telephone follow-up will be carried out at 6 months to collect self-reported data regarding physical activity and adherence to the Mediterranean diet. Discussion Preventive healthy aging programs should include health education with training in nutrition and lifestyles, while stressing the importance of and enhancing physical activity; the inclusion of new technologies can facilitate these goals. The EVIDENT-AGE study will incorporate a simple, accessible intervention with potential implementation in the care of older adults.This study was supported in part by grants funded by the Instituto de Salud Carlos III, Institute of Biomedical Research of Salamanca (IBSAL)-IBY17/00003, and the Spanish Research Network for Preventive Activities and Health Promotion in Primary Care (REDIAPP)-RD16/0007

Adaptability of invasive plants to climate change

[EN] Climate change represents one of the greatest environmental challenges of the 21st century, accentuated by deforestation and the degradation of habitats. Changes in vital aspects such as temperature, the amount and distribution of rainfall or the frequency of extreme meteorological phenomena will probably negatively affect ecosystems. The possibilities of invasion will predictably increase, being endemic species especially vulnerable to the effects of climate change. Invasive species are extremely adaptable to climate variability, as evidenced by their current large latitudinal ranges. Generally, invasive plants also have rapid dispersal characteristics, allowing them to vary their ranges in response to changing climatic conditions rapidly. As a result, these species could become more dominant in many areas under changing climatic conditions. In many situations, the environmental stress generated by climate change and invasive plants are synergistic: invasive species can exacerbate the impacts of climate change on ecosystems, and in the same way, climate change can allow new invasions.S.G-O acknowledges a 'Margarita Salas' postdoctoral contract from Universitat Politècnica de València and the Spanish Ministry of Universities, supported by the European Union - Next Generation fundsGonzález-Orenga, S.; Boscaiu, M.; Verdeguer Sancho, MM.; Sánchez-Moreiras, AM.; González, L.; Vicente, O. (2022). Adaptability of invasive plants to climate change. AgroLife Scientific Journal (Online). 11(2):58-65. https://doi.org/10.17930/AGL202227586511