The functional organization of mitochondrial genomes in human cells

BACKGROUND: We analyzed the organization and function of mitochondrial DNA in a stable human cell line (ECV304, which is also known as T-24) containing mitochondria tagged with the yellow fluorescent protein. RESULTS: Mitochondrial DNA is organized in ~475 discrete foci containing 6–10 genomes. These foci (nucleoids) are tethered directly or indirectly through mitochondrial membranes to kinesin, marked by KIF5B, and microtubules in the surrounding cytoplasm. In living cells, foci have an apparent diffusion constant of 1.1 × 10(-3 )μm(2)/s, and mitochondria always split next to a focus to distribute all DNA to one daughter. The kinetics of replication and transcription (monitored by immunolabelling after incorporating bromodeoxyuridine or bromouridine) reveal that each genome replicates independently of others in a focus, and that newly-made RNA remains in a focus (residence half-time ~43 min) long after it has been made. This mitochondrial RNA colocalizes with components of the cytoplasmic machinery that makes and imports nuclear-encoded proteins – that is, a ribosomal protein (S6), a nascent peptide associated protein (NAC), and the translocase in the outer membrane (Tom22). CONCLUSIONS: The results suggest that clusters of mitochondrial genomes organize the translation machineries on both sides of the mitochondrial membranes. Then, proteins encoded by the nuclear genome and destined for the mitochondria will be made close to mitochondrial-encoded proteins so that they can be assembled efficiently into mitochondrial complexes

Fisiopatología de los Cuerpos Libres Intraarticulares : estudio Experimental

La cubierta cartilaginosa de los cuerpos libres intraarticulares tiene un origen no bien conocido. Se ha realizado un estudio experimental en conejos, liberando fragmentos osteocondrales en la cavidad articular de la rodilla, estudiando sus cambios histológicos desde la primera semana hasta el año. En todos los casos los fragmentos osteocondrales se observaron adheridos a la membrana sinovial. Hubo una remodelación progresiva del componente óseo y cartilaginoso, cubriéndose todo el fragmento de una cubierta fibrocartilaginosa, reabsorbiéndose el hueso central y formándose nuevo hueso en la porción periférica debajo del fibrocartí- lago. Todos los cambios tisulares dependieron de la actividad de la membrana sinovial. No pudo demostrarse crecimiento del cartílago articular.It is not well known the origin of the cartilaginous outer layer of the intrarticular loose bodies. An experimental study has been carried out on rabbits loosening out osteochondral fragments into the articular cavity of the kne e joint and studying their histological changes between the first week and the first year. The osteochondral fragments wer e found adhered to the synovial membrane in all cases. A proggressive remodeling tood place within the osseous and cartilaginous components, the whole fragment became covered by a fibrocartilaginous covering, the central bone was reabsorbed and new bone was formed at the peripheral portion unde r fibrocartilage. All tissue change s wer e dependent on synovial membrane activity. Growth of articular cartilage could not be demonstrated

Cicatrización del fibrocartílago meniscal de la Rodilla : estudio Experimental

Para estudiar la cicatrización de las lesiones meniscales se ha realizado un estudio experimental en conejos. Se han practicado tres tipos de lesiones en el menisco, transversal, longitudinal parameniscal y longitudinal interna alejeda del paramenisco. Posteriormente el defecto creado era reparado mediante puntos sueltos con material reabsorvible. Se ha estudiado el fenómeno de cicatrización desde el punto de vista histológico desde la semana a los tres meses. Los resultados muestran que la cicatrización es fundamentalmente extrínseca a partir de la capacidad plástica de la membrana sinovial. Las heridas longitudinales parameniscales cicatrizaron sin dificultad, las transversales casi en toda su anchura y las longitudinales en zona avascular cicatrizaron principalmente en su porción anterior gracias a la invasión de sinovial hiperplásica desde la inserción tibial del ligamento cruzado anterior.To study the healing of meniscal tears, the authors hav e carried out an experimental work in rabbits. They performed three types of tears in the internal menisci, radial, peripheral longitudinal (in the parameniscal zone) and longitudinal within of the parameniscus. The menisci were reparated by suture with absorbible material. The healing phenomenon has been histologically studied from the first wee k to three months after. The results showed that the cicatrization is mainly extrinsic by the plastic capacity of sinovial membrane. The longitudinal tears in the parameniscus heal without difficulty, the transversal tears almost in their whol e width and the longitudinal tears at the avascular zone healed principally in the anterior portion by the invasion of hyperplasic sinovial from the tibial insertion of the anterior cruciate ligament

Fibrocartílago meniscal como biomaterial de sustitución en los Defectos Osteocondrales. Estudio experimental en el conejo con injertos homólogos

Los autores presentan un estudio experimental en el cual han empleado homoinjertos de fibrocartílago meniscal, para reparar defectos osteocondrales localizados en zona de carga, del cóndilo medial de la rodilla del conejo. Han sido estudiados 33 animales, realizando un estudio histológico, con periodos de evolución comprendidos entre una semana y 22 meses. Los homoinjertos meniscales parecen ser capaces de restaurar una superficie articular funcional. Conservan su estructura y celularidad a lo largo de toda la experiencia consiguiendo un perfecto anclaje al lecho óseo, adaptándose a la carga y sin producir cambios en el cartílago articular vecino. No se han producido rechazos.The authors report on an experimental study, employing meniscal fibrocartilage homo grafts to repair osteochondral defects in the weightbearing area of medial condile of rabbit knee. Thirty-three animals were studied by histological means for periods of one week to 22 months. The meniscal fibrocartilage homograft appeared capable of restoring a functional articular surface, maintaining its entire histological structure and celularity throughout the experiment, obtaining a perfect union with the bone tissue, adapting to the weightbearing and not modifying the neighboring articular surface. No evidence of rejection was observed

Rotura del ligamento deltoideo del tobillo: evaluación clínico-quirúrgica

No existe un criterio uniforme sobre la conduct a a seguir en el tratamient o de la rotur a del ligamento deltoideo del tobillo. Se ha n revisado 36 paciente s diagnosticados y tra - tado s quirúrgicament e de rotur a de dicho ligamento, la mayorí a de la s veces est a lesión iba acompañad a de fractur a del maleolo peroneo. Se ha valorado la etiología, el mecanismo lesional y los resultados siguiendo la clasificación de Cedell, considerándos e estos últimos como buenos en la práctic a totalidad de los casos. En cuatro de los paciente s (11%), se presentó como únic a secuela la limitación de la movilidad en los últimos grados de flexo-extensiónUniform criteria about the actions to be taken in the tearing of the ankle deltoid ligament d o no t exist. Thirt y si x patients diagnose d an d surgicall y treate d becaus e o f th e tearin g o f th e abov e mentione d ligamen t hav e bee n reviewed . Most o f th e times, this lesio n wa s accompanie d b y a fractur e o f th e peronea l maleolus. Etiology , injur y mechanism s an d results followin g Cedell's clasificatio n hav e bee n evaluate d an d th e results hav e bee n considere d goo d i n practicall y all cases. I n fou r patients, th e onl y secuel a wa s a limitatio n o f th e most extrem e grade s o f flexo-extension

Experiences Developing Safe and Fault-Tolerant Tele-Operated Service Robots. A Case Study in Shipyards

Human operators use tele-operated service robots for performing more or less hazardous operations (manipulation of heavy and/or dangerous products) in more or less hostile environments (nuclear reactors, space missions, warehouses, etc). Anyway, independently of the operation, the robot has to interact with both the environment it is working on and with human operators. Therefore, it is essential that the design (which include both software and hardware) of the robot involves no risk, or at least an acceptable level of risk, neither for the operators, nor for the environment nor for the robot itself. Nevertheless, it is not always possible to make a system free of failures in its design or operation. Apart from the risk inherent to the use of the mechanisms themselves, these systems work in hazardous environments, where the probability of the risk is higher than normal. Should a failure happen, its consequences could even involve the loss of human lives. (Neumann, 1994) documents many cases of computer-related failures, such as the Therac-25 (a radiation-therapy device), the missiles shield in Saudi Arabia, etc. Nevertheless, safety aspects are seldom included in the early phases of the system design process from the beginning, even though they are a critic aspect. Generally, safety has to conform and adapt to the already designed system and not vice versa, when it is widely known that safety involves not only the design of the software but also the hardware. Even more, a simple hardware solution can eliminate a hazard or simplify the software design in many situations.This research has been funded by the Spanish CICYT project MEDWSA (TIN2006-15175- C05-02) and the Regional Government of Murcia Séneca Program (02998-PI-05)

Characterization of polypyrrole/phosphotungstate membranes by electrochemical impedance spectroscopy

The aim of this study was to design and prepare multifunctional PPy/PW12O403- membranes useful for the development of smart textile fabrics and wastewaters treatments based on the application of electrochemical techniques. These PPy/PW12O403- membranes have been characterized by means of electrochemical impedance spectroscopy by using electrochemical cells with different configurations based on the use of two-, three-, or four-electrode experiments. The activation energy of the films in the temperature range 35-70 degrees C was 170 meV. It has been demonstrated that after measuring the PPy films in different NaCl solutions, both the rate of ionic exchange and the diffusion processes through the membrane are faster for more concentrated solutions. Ionic exchange and diffusion were very prevented with a large cation as tetramethylammonium. The impedance spectra obtained with metal/polymer/electrolyte configuration show that the electrical conduction developed through coatings in strong acid solution is controlled by finite-length diffusion processes with reflective boundary conditions. At pH 13, the electrical response proceeds through the oxide layer (Fe and Cr oxides) and the steel/electrolyte interface. In this case, the polymeric coating is very porous due to the counter-ion disintegration. The decomposition of the counter-ion was corroborated by means of energy dispersive X-ray and Fourier transform infrared spectroscopy. (C) 2013 Elsevier B.V. All rights reserved.Authors thank to the Spanish Ministerio de Ciencia e Innovacion (contract CTM2011-23583) and Universitat Politecnica de Valencia (Primeros Proyectos de Investigacion (PAID-06-10)) for the financial support. J. Molina is grateful to the Conselleria d'Educacio, Formacio i Ocupacio (Generalitat Valenciana) for the Programa VALi+D Postdoctoral Fellowship.Bonastre Cano, JA.; Molina Puerto, J.; Galvan, JC.; Cases Iborra, FJ. (2014). Characterization of polypyrrole/phosphotungstate membranes by electrochemical impedance spectroscopy. Synthetic Metals. 187:37-45. https://doi.org/10.1016/j.synthmet.2013.10.020S374518

Photoluminescence Activation of Organic Dyes via Optically Trapped Quantum Dots

This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Nano, copyright © American Chemical Society after peer review and technical editing by the publisher.[EN] Laser tweezers afford quantum dot (QD) manipulation for use as localized emitters. Here, we demonstrate fluorescence by radiative energy transfer from optically trapped colloidal QDs (donors) to fluorescent dyes (acceptors). To this end, we synthesized silica-coated QDs of different compositions and triggered their luminescence by simultaneous trapping and two-photon excitation in a microfluidic chamber filled with dyes. This strategy produces a near-field light source with great spatial maneuverability, which can be exploited to scan nanostructures. In this regard, we demonstrate induced photoluminescence of dye-labeled cells via optically trapped silica-coated colloidal QDs placed at their vicinity. Allocating nanoscale donors at controlled distances from a cell is an attractive concept in fluorescence microscopy because it dramatically reduces the number of excited dyes, which improves resolution by preventing interferences from the whole sample, while prolonging dye luminescence lifetime due to the lower power absorbed from the QDs.H.R.-R. is supported by an FPI-UAM 2015 fellowship (BES-2009-027909). Authors acknowledge funding from the Spanish Ministry of Economy and Competitiveness through MAT2017-85617-R and MAT2015-71806-R. B.H.J. acknowledges financial support from the Spanish Ministry of Economy and Competitiveness, through the Maria de Maeztu (IFIMAC) and Severo Ochoa (IMDEA Nanoscience) Programmes for Units of Excellence in R&D.Rodríguez-Rodríguez, H.; Acebrón, M.; Iborra, F.; Arias-Gonzalez, JR.; Juárez, B. (2019). Photoluminescence Activation of Organic Dyes via Optically Trapped Quantum Dots. ACS Nano. 13(6):7223-7230. https://doi.org/10.1021/acsnano.9b02835S7223723013

Connecting Variability in Global Transcription Rate to Mitochondrial Variability

The authors demonstrate a connection between variability in the rate of transcription and differences in cellular mitochondrial content

Coregulated human globin genes are frequently in spatial proximity when active

The organization of genes within the nucleus may influence transcription. We have analyzed the nuclear positioning of the coordinately regulated α- and β-globin genes and show that the gene-dense chromatin surrounding the human α-globin genes is frequently decondensed, independent of transcription. Against this background, we show the frequent juxtaposition of active α- and β-globin genes and of homologous α-globin loci that occurs at nuclear speckles and correlates with transcription. However, we did not see increased colocalization of signals, which would be expected with direct physical interaction. The same degree of proximity does not occur between human β-globin genes or between murine globin genes, which are more constrained to their chromosome territories. Our findings suggest that the distribution of globin genes within erythroblast nuclei is the result of a self-organizing process, involving transcriptional status, diffusional ability of chromatin, and physical interactions with nuclear proteins, rather than a directed form of higher-order control