1,909 research outputs found
Switch between morphospecies of pocillopora corals
© 2015 by The University of Chicago. All rights reserved. Pocillopora corals are the main reef builders in the eastern tropical Pacific. The validity of Pocillopora morphospecies remains under debate because of disagreements between morphological and genetic data. To evaluate the temporal stability of morphospecies in situ, we monitored the shapes of individual colonies in three communities in the southern Gulf of California for 44 months. Twenty-three percent of tagged colonies of Pocillopora damicornis changed to Pocillopora inflata morphology during this time. This switch in identity coincided with a shift to a higher frequency of storms and lower water turbidity (i.e., lower chlorophyll a levels). Seven months after the switch, P. inflata colonies were recovering their original P. damicornis morphology. All colonies of both morphospecies shared a common mitochondrial identity, but most P. damicornis colonies undergoing change were at a site with low-flow conditions. This is the first in situ study to document switching between described morphospecies, and it elucidates the influence of temporal shifts in environmental conditions on morphologically plastic responses
Morphological variation and different branch modularity across contrasting flow conditions in dominant Pocillopora reef-building corals
© 2015, Springer-Verlag Berlin Heidelberg. Pocillopora corals, the dominant reef-builders in the Eastern Tropical Pacific, exhibit a high level of phenotypic plasticity, making the interpretation of morphological variation and the identification of species challenging. To test the hypothesis that different coral morphospecies represent phenotypes that develop in different flow conditions, we compared branch characters in three Pocillopora morphospecies (P.damicornis, P. verrucosa, and P. meandrina) from two communities in the Gulf of California exposed to contrasting flow conditions. Morphological variation and branch modularity (i.e., the tendency of different sets of branch traits to vary in a coordinated way) were assessed in colonies classified as Pocillopora type 1 according to two mitochondrial regions. Our results can be summarized as follows. (1) Pocillopora type 1 morphospecies corresponded to a pattern of morphological variation in the Gulf of California. Overall, P.damicornis had the thinnest branches and its colonies the highest branch density, followed by P.verrucosa, and then by P.meandrina, which had the thickest branches and its colonies the lowest branch density. (2) The differentiation among morphospecies was promoted by different levels of modularity of traits. P.verrucosa had the highest coordination of traits, followed by P.damicornis, and P.meandrina. (3) The variation and modularity of branch traits were related to water flow condition. Morphology under the high-flow condition was more similar among morphospecies than under the low-flow condition and seemed to be related to mechanisms for coping with these conditions. Our results provide the first evidence that in scleractinian corals different levels of modularity can be promoted by different environmental conditions
The Eastern Tropical Pacific coral population connectivity and the role of the Eastern Pacific Barrier
Long-distance dispersal is believed to strongly influence coral reef population dynamics across the Tropical Pacific. However, the spatial scale and strength at which populations are potentially connected by dispersal remains uncertain. To determine the patterns in connectivity between the Eastern (ETP) and Central Tropical Pacific (CTP) ecoregions, we used a biophysical model incorporating ocean currents and larval biology to quantify the seascape-wide dispersal potential among all population. We quantified the likelihood and determined the oceanographic conditions that enable the dispersal of coral larvae across the Eastern Pacific Barrier (EP-Barrier) and identified the main connectivity pathways and their conservation value for dominant reef-building corals. Overall, we found that coral assemblages within the CTP and ETP are weakly connected through dispersal. Although the EP-Barrier isolates the ETP from the CTP ecoregion, we found evidence that the EP-Barrier may be breached, in both directions, by rare dispersal events. These rare events could explain the evolutionary genetic similarity among populations of pocilloporids in the ecoregions. Moreover, the ETP may function as a stronger source rather than a destination, providing potential recruits to CTP populations. We also show evidence for a connectivity loop in the ETP, which may positively influence long-term population persistence in the region. Coral conservation and management communities should consider eight-key stepping stone ecoregions when developing strategies to preserve the long-distance connectivity potential across the ETP and CTP
Real time approach to tunneling in open quantum systems: decoherence and anomalous diffusion
Macroscopic quantum tunneling is described using the master equation for the
reduced Wigner function of an open quantum system at zero temperature. Our
model consists of a particle trapped in a cubic potential interacting with an
environment characterized by dissipative and normal and anomalous diffusion
coefficients. A representation based on the energy eigenfunctions of the
isolated system, i.e. the system uncoupled to the environment, is used to write
the reduced Wigner function, and the master equation becomes simpler in that
representation. The energy eigenfunctions computed in a WKB approximation
incorporate the tunneling effect of the isolated system and the effect of the
environment is described by an equation that it is in many ways similar to a
Fokker-Planck equation. Decoherence is easily identified from the master
equation and we find that when the decoherence time is much shorter than the
tunneling time the master equation can be approximated by a Kramers like
equation describing thermal activation due to the zero point fluctuations of
the quantum environment. The effect of anomalous diffusion can be dealt with
perturbatively and its overall effect is to inhibit tunneling.Comment: 25 pages, 1 figur
Resistencia a fármacos antituberculosis en pacientes coinfectados con tuberculosis y virus de la inmunodeficiencia humana, en un hospital de referencia de 2007 a 2010 en Cali (Colombia)
ResumenObjetivoLa resistencia a los fármacos antituberculosis es de gran interés en salud pública. La coinfección con virus de la inmunodeficiencia humana (VIH) ha cambiado el comportamiento de dicha enfermedad. El objetivo de nuestro estudio es determinar la prevalencia de la resistencia a fármacos antituberculosis en pacientes coinfectados con tuberculosis (TB)/VIH. Método: Se realizó un estudio retrospectivo a partir de la revisión de los registros clínicos de casos nuevos y fracasos de TB coinfectados con VIH que consultaron a un centro de atención de nivel IV desde 2007 a 2010 y que contaban con pruebas de susceptibilidad. Resultados: Un 52% de los pacientes procedían de Santiago de Cali, y un 8%, de Buenaventura. La TB se presentó de forma extrapulmonar en el 80% de los pacientes. Del 48% de los sujetos que conocían su estado VIH previo al diagnóstico de la TB, el 40% estaban en terapia antirretroviral. El 16% de los casos eran fracasos, entre los cuales se detectó un caso multi-drogorresistente. De los casos nuevos, se encontró monorresistencia a la isoniazida del 14%, y una resistencia total del 28%.ConclusionesSe encontró una mayor prevalencia de resistencia a la esperada en población coinfectada TB/VIH; por lo que es necesario fortalecer el trabajo en equipo entre las entida-des públicas y privadas para controlar dicha situación y fomentar el diagnóstico temprano y la realización de pruebas de susceptibilidad a fármacos antituberculosis.AbstractBackgroundResistance to anti-tuberculosis treatment is a matter of great interest in terms of public health. TB/HIV coinfection changed what was previously known about TB. Our study attempts to determine the prevalence of resistance to TB drugs among a local TB/HIV population.MethodsA retrospective study was conducted, which consisted of a review of the clinical records of new and relapsing cases of TB/HIV coinfected patients, with drug susceptibility tests, who attended an advanced medical care centre in Cali, Colombia, between 2007 and 2010.ResultsJust over half (52%) of the patients were native from Cali, and 8% were from Buenaventura. An extra-pulmonary presentation of TB was seen in 80% of the subjects. Almost half (48%) were HIV positive before the diagnosis of tuberculosis was made, 40% of whom were on HAART treatment. Of the total cases, 16% were relapses, including one case of multi-drug resistant (MDR)-TB. Among the new cases, 14% were resistant to isoniazid only, making a total of 28% being resistant to this.ConclusionsThere was a higher than expected prevalence of resistance in TB/HIV patients. There is an urgent need to improve the team work between public health organizations and private medical institutions, and this cooperation should be of great priority, as it is a means to control and promote early diagnosis with drug-susceptibility tests
Distribución del coral arrecifal Pocillopora inflata (Scleractinia) en el Pacífico Mexicano y comentarios sobre su situación taxonómica
Background. The geographic distribution of reef corals in the eastern Pacific is well documented. However, field surveys still produce new geographic records of the taxa. Goals. The objective of this paper is to present a detailed compilation of the areas of occurrence of the Pocillopora inflata in Mexico, provide observations on its distribution range and comment on the taxonomic validity of the records of this species in the country. Methods. Data regarding distribution of the species in the Eastern Pacific and Mexican Pacific were gathered from published sources and field logs. Results. The distribution of P. inflata ranges from the southern Gulf of California (including new records for four locations of Baja California Sur, along the 24°N parallel), Nayarit, Colima, Guerrero and Oaxaca (to Huatulco Bays; 15°N). This new data call for a modification of the distribution map for the taxon in the Red List of the International Union for Conservation of Nature. Conclusions. Repeated observations in the Gulf of California revealed that, due to the remarkable phenotypic plasticity of another species (P. damicornis), confusion may arise with the identification of P. inflata in the field, since the general form of this species, is quite similar to the branches of P. damicornis affected by storms.Antecedentes. La distribución de los corales del Pacífico Oriental está bien caracterizada, sin embargo prospecciones de campo siguen arrojando nuevos registros geográficos de los taxa. Objetivos. Presentar una recopilación detallada de las zonas de presencia del coral Pocillopora inflata, en México, aportar observaciones que extienden su ámbito de distribución y discutir algunos aspectos sobre la validez taxonómica de los registros de la especie en el país. Métodos. Se compilaron datos de distribución de la especie en el Pacífico Oriental y datos de campo del taxón en el Pacífico mexicano. Resultados. Los resultados indican que la distribución de P. inflata comprende el sur del Golfo de California (incluyendo nuevos registros en cuatro localidades de Baja California Sur, dentro del paralelo 24°N), Nayarit, Colima, Guerrero y Oaxaca (hasta Bahías de Huatulco; 15°N). Los nuevos datos modifican el mapa de distribución reconocido para el taxón en la Lista Roja de la Unión Internacional para la Conservación de la Naturaleza. Conclusiones. Observaciones llevadas a cabo repetidamente en el Golfo de California evidencian que debido a la gran plasticidad fenotípica de otra morfoespecie (P. damicornis), puede haber confusiones al identificar P. inflata en el campo, ya que la forma general de esta especie y la de las ramas de P. damicornis afectadas por tormentas, llega a ser muy similar
Interleukin-6 Increases Rat Metalloproteinase-13 Gene Expression through Stimulation of Activator Protein 1 Transcription Factor in Cultured Fibroblasts
The role of IL-6 in collagen production and tissue remodeling is controversial. In Rat-1 fibroblasts, we measured the effect of IL-6 on matrix metalloproteinase-13 (MMP-13), c-jun, junB, and c-fos gene expression, binding of activator protein 1 (AP1) to DNA, amount of AP1 proteins, immunoreactive MMP-13 and TIMP-1 proteins, and Jun N-terminal kinase activity. We show that IL-6 increased MMP-13-mRNA and MMP-13 protein. These effects were exerted by acting on the AP1-binding site of the MMP-13 promoter, as shown by transfecting cells with reporter plasmids containing mutations in this element. Mobility shift assays demonstrated that IL-6 induced the DNA binding activity of AP1. This effect was accompanied by a marked increase in c-Jun, JunB, and c-Fos mRNA, as well as in c-Jun protein and its phosphorylated form. The latter is not due to increased Jun N-terminal kinase activity but to a decreased serine/threonine phosphatase activity. We conclude that IL-6 increases interstitial MMP-13 gene expression at the promoter level. This effect seems to be mediated by the induction of c-jun, junB, and c-fos gene expression, by the binding of AP1 to DNA, by increasing phosphorylated c-Jun, and by the inhibition of serine/threonine phosphatase activity. These effects of IL-6 might contribute to remodeling connective tissue
Nuclear translocation of glutaminase GLS2 in human cancer cells associates with proliferation arrest and differentiation
Glutaminase (GA) catalyzes the first step in mitochondrial glutaminolysis playing a key role in cancer metabolic reprogramming. Humans express two types of GA isoforms: GLS and GLS2. GLS isozymes have been consistently related to cell proliferation, but the role of GLS2 in cancer remains poorly understood. GLS2 is repressed in many tumor cells and a better understanding of its function in tumorigenesis may further the development of new therapeutic approaches. We analyzed GLS2 expression in HCC, GBM and neuroblastoma cells, as well as in monkey COS-7 cells. We studied GLS2 expression after induction of differentiation with phorbol ester (PMA) and transduction with the full-length cDNA of GLS2. In parallel, we investigated cell cycle progression and levels of p53, p21 and c-Myc proteins. Using the baculovirus system, human GLS2 protein was overexpressed, purified and analyzed for posttranslational modifications employing a proteomics LC-MS/MS platform. We have demonstrated a dual targeting of GLS2 in human cancer cells. Immunocytochemistry and subcellular fractionation gave consistent results demonstrating nuclear and mitochondrial locations, with the latter being predominant. Nuclear targeting was confirmed in cancer cells overexpressing c-Myc- and GFP-tagged GLS2 proteins. We assessed the subnuclear location finding a widespread distribution of GLS2 in the nucleoplasm without clear overlapping with specific nuclear substructures. GLS2 expression and nuclear accrual notably increased by treatment of SH-SY5Y cells with PMA and it correlated with cell cycle arrest at G2/M, upregulation of tumor suppressor p53 and p21 protein. A similar response was obtained by overexpression of GLS2 in T98G glioma cells, including downregulation of oncogene c-Myc. Furthermore, human GLS2 was identified as being hypusinated by MS analysis, a posttranslational modification which may be relevant for its nuclear targeting and/or function. Our studies provide evidence for a tumor suppressor role of GLS2 in certain types of cancer. The data imply that GLS2 can be regarded as a highly mobile and multilocalizing protein translocated to both mitochondria and nuclei. Upregulation of GLS2 in cancer cells induced an antiproliferative response with cell cycle arrest at the G2/M phase
Pantothenate Rescues Iron Accumulation in Pantothenate Kinase-Associated Neurodegeneration Depending on the Type of Mutation
Neurodegeneration with brain iron accumulation (NBIA) is a group of inherited neurologic disorders in which iron accumulates in the basal ganglia resulting in progressive dystonia, spasticity, parkinsonism, neuropsychiatric abnormalities, and optic atrophy or retinal degeneration. The most prevalent form of NBIA is pantothenate kinase-associated neurodegeneration (PKAN) associated with mutations in the gene of pantothenate kinase 2 (PANK2), which is essential for coenzyme A (CoA) synthesis. There is no cure for NBIA nor is there a standard course of treatment. In the current work, we describe that fibroblasts derived from patients harbouring PANK2 mutations can reproduce many of the cellular pathological alterations found in the disease, such as intracellular iron and lipofuscin accumulation, increased oxidative stress, and mitochondrial dysfunction. Furthermore, mutant fibroblasts showed a characteristic senescent morphology. Treatment with pantothenate, the PANK2 enzyme substrate, was able to correct all pathological alterations in responder mutant fibroblasts with residual PANK2 enzyme expression. However, pantothenate had no effect on mutant fibroblasts with truncated/incomplete protein expression. The positive effect of pantothenate in particular mutations was also confirmed in induced neurons obtained by direct reprograming of mutant fibroblasts. Our results suggest that pantothenate treatment can stabilize the expression levels of PANK2 in selected mutations. These results encourage us to propose our screening model as a quick and easy way to detect pantothenate-responder patients with PANK2 mutations. The existence of residual enzyme expression in some affected individuals raises the possibility of treatment using high dose of pantothenate.Instituto de Salud Carlos III FIS PI16/00786Junta de Andalucía CTS-5725, BIO-122Dirección General de Investigación Científica y Técnica BFU2015-64536-
Long-Term Outcomes After Autologous Versus Allogeneic Stem Cell Transplantation in Molecularly-Stratified Patients With Intermediate Cytogenetic Risk Acute Myeloid Leukemia: A PETHEMA Study
PETHEMA (Programa Español de Tratamientos en Hematología) and GETH (Grupo Espa~nol de Trasplante Hematopoyético y Terapia Celular) Cooperative GroupsAcute myeloid leukemia (AML) with intermediate risk cytogenetics (IRcyto) comprises a variety of biological entities with distinct mutational landscapes that translate into differential risks of relapse and prognosis. Optimal postremission therapy choice in this heterogeneous patient population is currently unsettled. In the current study, we compared outcomes in IRcyto AML recipients of autologous (autoSCT) (n = 312) or allogeneic stem cell transplantation (alloSCT) (n = 279) in first complete remission (CR1). Molecular risk was defined based on CEBPA, NPM1, and FLT3-ITD mutational status, per European LeukemiaNet 2017 criteria. Five-year overall survival (OS) in patients with favorable molecular risk (FRmol) was 62% (95% confidence interval [CI], 50-72) after autoSCT and 66% (95% CI, 41-83) after matched sibling donor (MSD) alloSCT (P = .68). For patients of intermediate molecular risk (IRmol), MSD alloSCT was associated with lower cumulative incidence of relapse (P < .001), as well as with increased nonrelapse mortality (P = .01), as compared to autoSCT. The 5-year OS was 47% (95% CI, 34-58) after autoSCT and 70% (95% CI, 59-79) after MSD alloSCT (P = .02) in this patient subgroup. In a propensity-score matched IRmol subcohort (n = 106), MSD alloSCT was associated with superior leukemia-free survival (hazard ratio [HR] 0.33, P = .004) and increased OS in patients alive 1 year after transplantation (HR 0.20, P = .004). These results indicate that, within IRcyto AML in CR1, autoSCT may be a valid option for FRmol patients, whereas MSD alloSCT should be the preferred postremission strategy in IRmol patients.Supported by a Río Hortega academic clinical fellowship (CM19/00194) from the Instituto de Salud Carlos III, Spain (E.R.A.). Additional funding has been provided by CIBERONC grants to J.P.S. (CB16/12/00480), M.M.S. (CB16/12/00369) and B.V. (CB16/12/00233)
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