445 research outputs found
The photosynthetic cytochrome c 550 from the diatom Phaeodactylum tricornutum
The photosynthetic cytochrome c550 from the marine diatom Phaeodactylum tricornutum has been purified and characterized. Cytochrome c550 is mostly obtained from the soluble cell extract in relatively large amounts. In addition, the protein appeared to be truncated in the last hydrophobic residues of the C-terminus, both in the soluble cytochrome c550 and in the protein extracted from the membrane fraction, as deduced by mass spectrometry analysis and the comparison with the gene sequence. Interestingly, it has been described that the C-terminus of cytochrome c550 forms a hydrophobic finger involved in the interaction with photosystem II in cyanobacteria. Cytochrome c550 was almost absent in solubilized photosystem II complex samples, in contrast with the PsbO and Psb31 extrinsic subunits, thus suggesting a lower affinity of cytochrome c550 for the photosystem II complex. Under iron-limiting conditions the amount of cytochrome c550 decreases up to about 45% as compared to iron-replete cells, pointing to an iron-regulated synthesis. Oxidized cytochrome c550 has been characterized using continuous wave EPR and pulse techniques, including HYSCORE, and the obtained results have been interpreted in terms of the electrostatic charge distribution in the surroundings of the heme centre.This work was supported by the Spanish Ministry of Economy and Competitiveness (BIO2012-35271, BIO2015-64169-P, MAT2011-23861 and CTQ2015-64486-R) the Andalusian Government (PAIDI BIO-022) and the Aragón Government (Grupo consolidado B-18). All these grants were partially financed by the EU FEDER ProgramPeer reviewe
Aptitud combinatoria y heterosis en híbridos de líneas endogámicas de maíz/Combining ability and heterosis in hybrids from inbred lines corn
El trabajo se realizó en dos etapas, en la primera se formaron las cruzas en el campo experimental de
la Universidad Autónoma Agraria Antonio Narro Unidad Laguna (UAAAN-UL), y en la segunda la evaluación en el
campo experimental de la UAAAN-UL en los ciclos agrícola primavera y verano, y en el ejido Niágara, en el municipio
de Aguascalientes, Aguascalientes, en primavera. El material genético fueron 17 líneas endogámicas, cuatro de la
UAAAN-UL, dos del INIFAP y 11 del CIMMYT. El objetivo fue estimar la aptitud combinatoria general (ACG) de las
líneas, la aptitud combinatoria especíca (ACE) y cuanticar los efectos genéticos y la heterosis de las cruzas. Para la
ACG sobresalieron las líneas macho LAN-388P, LB-32 y LB-40, y las líneas hembras CML-319, CML-318 y CML-278;
para la ACE los mayores valores lo tuvieron las cruzas LAN-123xCML-278 (3.28 t ha−1
), LAN-123xCML-318 (1.9 t
ha−1
), LB-40xCML-319 (1.7 t ha−1
) y LAN-388PxCML-264 (1.52 t ha−1
). Mientras que el mayor rendimiento de
grano, lo tuvieron las cruzas LB-40xCML-319 (14.49 t ha−1
), LB-32xCML-319 (14.17 t ha−1
), LAN-388PxCML-264
(13.68 t ha−1
), LAN-123xCML-278 (13.55 t ha−1
) y LAN-388PxCML-278 (13.44 t ha−1
). La varianza de dominancia
superó a la varianza aditiva en rendimiento de grano (RG) y en los principales componentes del rendimiento. Se
encontraron efectos positivos de heterosis para rendimiento de grano con respecto al progenitor superior en las cruzas
LB-40xCML-319 y LB-32 x CML-31
Analysis of cognitive performance and polymorphisms of SORL1, PVRL2, CR1, TOMM40, APOE, PICALM, GWAS_14q, CLU, and BIN1 in patients with mild cognitive impairment and cognitively healthy controls
Introduction: Alzheimer disease risk polymorphisms have been studied in patients with dementia, but have not yet been explored in mild cognitive impairment (MCI) in our population; nor have they been addressed in relation to cognitive variables, which can be predictive biomarkers of disease. Objective: To evaluate cognitive performance and presence of polymorphisms of the genes SORL1(rs11218304), PVRL2(rs6859), CR1(rs6656401), TOMM40(rs2075650), APOE (isoforms ε2, ε3, ε4), PICALM(rs3851179), GWAS_14q(rs11622883), BIN1(rs744373), and CLU(rs227959 and rs11136000) in patients with MCI and healthy individuals. Methodology: We performed a cross-sectional, exploratory, descriptive study of a prospective cohort of participants selected by non-probabilistic sampling, evaluated with neurological, neuropsychological, and genetic testing, and classified as cognitively healthy individuals and patients with MCI. Cognition was evaluated with the Neuronorma battery and analysed in relation to the polymorphic variants by means of measures of central tendency, confidence intervals, and nonparametric statistics. Results: We found differences in performance in language and memory tasks between carriers and non-carriers of BIN1, CLU, and CR1 variants and a trend towards poor cognitive performance for PICALM, GWAS_14q, SORL1, and PVRL2 variants; the APOE and TOMM40 variants were not associated with poor cognitive performance. Discussion: Differences in cognitive performance associated with these polymorphic variants may suggest that the mechanisms regulating these genes could have an effect on cognition in the absence of dementia; however, this study was exploratory and hypotheses based on these results must be explored in larger samples. Resumen: Introducción: Los polimorfismos de riesgo para el desarrollo de enfermedad de Alzheimer se han estudiado en pacientes con demencia, pero aún no se han explorado en trastorno neurocognitivo leve (TNL) en nuestra población, ni se han considerado en relación con variables cognitivas, las cuales pueden ser biomarcadores predictivos de enfermedad. Objetivo: Evaluar los desempeños cognitivos y los polimorfismos en los genes SORL1(rs11218304), PVRL2(rs6859), CR1(rs6656401), TOMM40(rs2075650), APOE(isoformas ε2, ε3, ε4), PICALM(rs3851179), GWAS_14q(rs11622883), BIN(rs744373), CLU (rs227959 y rs11136000) en pacientes con TNL y en sujetos sanos. Metodología: Estudio descriptivo, exploratorio y transversal, en una cohorte prospectiva de participantes seleccionados mediante muestreo no probabilístico, evaluados por neurología, neuropsicología y genética, y clasificados como cognitivamente sanos y pacientes con TNL, según criterios. La cognición se evaluó por medio de la batería Neuronorma y se analizó en relación con las variantes polimórficas por medio de medidas de tendencia, intervalos de confianza y estadísticos no paramétricos. Resultados: Se identificaron diferencias en los desempeños en tareas de lenguaje y memoria en relación con las variantes de BIN1, CLU y CR1, junto con tendencias en las variantes de PICALM, GWArs, SORL y PVRL2, mientras que en APOE y TOMM40 no se encontraron tendencias. Discusión: Las tendencias en los desempeños cognitivos en relación con variantes polimórficas podrían indicar que, en ausencia de demencia, los mecanismos que regulan estos genes podrían tener un efecto sobre la cognición; sin embargo, esta aproximación tiene un carácter exploratorio y sus resultados permiten generar hipótesis que requieren ser exploradas en muestras de mayor tamaño
KAPAO First Light: the design, construction and operation of a low-cost natural guide star adaptive optics system
We present the instrument design and first light observations of KAPAO, a natural guide star adaptive optics (AO) system for the Pomona College Table Mountain Observatory (TMO) 1-meter telescope. The KAPAO system has dual science channels with visible and near-infrared cameras, a Shack-Hartmann wavefront sensor, and a commercially available 140-actuator MEMS deformable mirror. The pupil relays are two pairs of custom off-axis parabolas and the control system is based on a version of the Robo-AO control software. The AO system and telescope are remotely operable, and KAPAO is designed to share the Cassegrain focus with the existing TMO polarimeter. We discuss the extensive integration of undergraduate students in the program including the multiple senior theses/capstones and summer assistantships amongst our partner institutions. This material is based upon work supported by the National Science Foundation under Grant No. 0960343
Hyperspectral imaging benchmark based on machine learning for intraoperative brain tumour detection
publishedVersio
Performance of the inFLUenza Patient-Reported Outcome (FLU-PRO) diary in patients with influenza-like illness (ILI)
BACKGROUND: The inFLUenza Patient Reported Outcome (FLU-PRO) measure is a daily diary assessing signs/symptoms of influenza across six body systems: Nose, Throat, Eyes, Chest/Respiratory, Gastrointestinal, Body/Systemic, developed and tested in adults with influenza. OBJECTIVES: This study tested the reliability, validity, and responsiveness of FLU-PRO scores in adults with influenza-like illness (ILI). METHODS: Data from the prospective, observational study used to develop and test the FLU-PRO in influenza virus positive patients were analyzed. Adults (≥18 years) presenting with influenza symptoms in outpatient settings in the US, UK, Mexico, and South America were enrolled, tested for influenza virus, and asked to complete the 37-item draft FLU-PRO daily for up to 14-days. Analyses were performed on data from patients testing negative. Reliability of the final, 32-item FLU-PRO was estimated using Cronbach's alpha (α; Day 1) and intraclass correlation coefficients (ICC; 2-day reproducibility). Convergent and known-groups validity were assessed using patient global assessments of influenza severity (PGA). Patient report of return to usual health was used to assess responsiveness (Day 1-7). RESULTS: The analytical sample included 220 ILI patients (mean age = 39.3, 64.1% female, 88.6% white). Sixty-one (28%) were hospitalized at some point in their illness. Internal consistency reliability (α) of FLU-PRO Total score was 0.90 and ranged from 0.72-0.86 for domain scores. Reproducibility (Day 1-2) was 0.64 for Total, ranging from 0.46-0.78 for domain scores. Day 1 FLU-PRO scores correlated (≥0.30) with the PGA (except Gastrointestinal) and were significantly different across PGA severity groups (Total: F = 81.7, p<0.001; subscales: F = 6.9-62.2; p<0.01). Mean score improvements Day 1-7 were significantly greater in patients reporting return to usual health compared with those who did not (p<0.05, Total and subscales, except Gastrointestinal and Eyes). CONCLUSIONS: Results suggest FLU-PRO scores are reliable, valid, and responsive in adults with influenza-like illness
VOLUMEN 16, NÚMERO 30 (1983-1984)
PROYECTO GEOTÉRMICO CHILES - CERRO NEGRO. Lozano, E.; Cruz, L.ZONAS HIDROGEOLÓGICAS DE COLOMBIA. Lobo-Guerrero, A.ESTUDIO GEOQUÍMICO Y PETROGRÁFICO DE ROCAS SUBVOLCÁNICAS ENTRE LA QUEBRADA CHIRAPOTO Y EL RÍO ARQUÍA (DEPARTAMENTO DE ANTIOQUIA Y CALDAS). Sánchez, L. H.; Parra, R. A.; Ortíz, F.GEOLOGÍA Y EXPERIENCIAS CONSTRUCTIVAS EN EL TÚNEL TUNJITA. Tejada, S. E.CONTRIBUCIÓN AL CONOCIMIENTO DEL PALEOZOICO SUPERIOR EN LA SECCIÓN QUETAME - VILLAVICENCIO. Cortés, R.; De La Espriella, R.TECTÓNICA GRAVITACIONAL EN LA CORDILLERA ORIENTAL AL ESTE DE LA FALLA DE BOYACÁ (DEPARTAMENTO DE BOYACÁ). Reyes, Ch. I.AMBIENTES GEOLÓGICOS URANÍFEROS EN COLOMBIA. Ortega Montero, C
Phenotypic Variation and Bistable Switching in Bacteria
Microbial research generally focuses on clonal populations. However, bacterial cells with identical genotypes frequently display different phenotypes under identical conditions. This microbial cell individuality is receiving increasing attention in the literature because of its impact on cellular differentiation, survival under selective conditions, and the interaction of pathogens with their hosts. It is becoming clear that stochasticity in gene expression in conjunction with the architecture of the gene network that underlies the cellular processes can generate phenotypic variation. An important regulatory mechanism is the so-called positive feedback, in which a system reinforces its own response, for instance by stimulating the production of an activator. Bistability is an interesting and relevant phenomenon, in which two distinct subpopulations of cells showing discrete levels of gene expression coexist in a single culture. In this chapter, we address techniques and approaches used to establish phenotypic variation, and relate three well-characterized examples of bistability to the molecular mechanisms that govern these processes, with a focus on positive feedback.
VOLUMEN 16, NÚMERO 30 (1983-1984)
PROYECTO GEOTÉRMICO CHILES - CERRO NEGRO. Lozano, E.; Cruz, L.ZONAS HIDROGEOLÓGICAS DE COLOMBIA. Lobo-Guerrero, A.ESTUDIO GEOQUÍMICO Y PETROGRÁFICO DE ROCAS SUBVOLCÁNICAS ENTRE LA QUEBRADA CHIRAPOTO Y EL RÍO ARQUÍA (DEPARTAMENTO DE ANTIOQUIA Y CALDAS). Sánchez, L. H.; Parra, R. A.; Ortíz, F.GEOLOGÍA Y EXPERIENCIAS CONSTRUCTIVAS EN EL TÚNEL TUNJITA. Tejada, S. E.CONTRIBUCIÓN AL CONOCIMIENTO DEL PALEOZOICO SUPERIOR EN LA SECCIÓN QUETAME - VILLAVICENCIO. Cortés, R.; De La Espriella, R.TECTÓNICA GRAVITACIONAL EN LA CORDILLERA ORIENTAL AL ESTE DE LA FALLA DE BOYACÁ (DEPARTAMENTO DE BOYACÁ). Reyes, Ch. I.AMBIENTES GEOLÓGICOS URANÍFEROS EN COLOMBIA. Ortega Montero, C
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