jueves, 31 de julio de 2014
jueves, 17 de julio de 2014
Marcapasos biológico
http://www.abc.es/salud/noticias/20140717/abci-marcapasos-biologico-201407161428.html
martes, 3 de junio de 2014
El hallazgo permite estudiar el desplazamiento de los cromosomas
Es una investigación conducida por el CNIC y el CNIO
Permitirá crear nuevas dianas terapéuticas y terapias
Un proyecto español de nanotecnología busca detectar enfermedades de forma precoz
Un equipo de investigadores españoles ha logrado reproducir modificaciones en los cromosomas de células humanas idénticas a las de dos tipos de cáncer, el sarcoma de Ewing y la leucemia mieloide aguda .
La leucemia mieloide aguda es un tipo de cáncer de la sangre y la médula ósea, mientras que el sarcoma de Ewing es un tipo de tumor óseo que afecta a niños y adolescentes.
La nueva tecnología desarrollada, basada en el empleo de herramientas moleculares para la manipulación del genoma, permitirá generar modelos de trabajo inexistentes hasta ahora para el estudio de la biología de los tumores y, en segundo lugar, su aplicación permitirá avanzar en la creación de nuevas dianas terapéuticas y terapias.
Intercambio de ADN entre cromosomas
Las alteraciones que conducen al desarrollo de tumores responden a múltiples cambios en la fisiología celular y en particular en el genoma de la célula.
Modelos celulares adecuados
"Investigar este tipo de tumores se ha visto obstaculizado hasta la fecha por la falta de modelos celulares y animales adecuados", señala el investigador del CNIC Juan Carlos Ramírez, uno de los autores del trabajo, que añade que la dificultad de generar las translocaciones cromosómicas ha impedido disponer de células alteradas únicamente en lo que es una 'marca' de la enfermedad: la presencia de translocaciones cromosómicas específicas.
http://www.rtve.es/noticias/20140603/reproducen-celulas-humanas-modificaciones-cromosomicas-propias-del-cancer/947550.shtml
miércoles, 7 de mayo de 2014
Un trabajo de investigación, publicado hoy en la revista Stem Cell Reports, abre la puerta a nuevos avances en medicina regenerativa y arroja luz sobre determinados tipos de tumores en que la 'ruta Wnt' está implicada
Investigadores del Centro de Regulación Genómica (CRG) de Barcelona (noreste) han descubierto que la denominada "ruta Wnt", una serie de reacciones bioquímicas que se producen en las células, desempeña un papel clave en el proceso de convertir células adultas en células pluripotentes.
Gurdon y Shinya Yamakana recibieron el Premio Nobel de Medicina por descubrir que las células adultas se pueden reprogramar para transformarse en células madre pluripotentes (IPS) capaces de comportarse de forma similar a las células madre embrionarias y con un enorme potencial en medicina regenerativa.
Pero pese a que hay muchos investigadores que estudian este proceso, de momento sigue sin comprenderse por completo y sin ser del todo eficiente y seguro como para convertirse en la base de una nueva terapia celular.
Los investigadores del centro de Barcelona han avanzado hacia la comprensión de la reprogramación celular y su eficacia al descubrir el papel clave de la ruta de señalización Wnt en la transformación de células adultas a IPS.
Nosotros hemos descubierto que podemos incrementar la eficiencia del proceso inhibiendo la ruta Wnt", explicó Francesco Aulicino, estudiante de doctorado en el Grupo de Reprogramación y Regeneración.
http://www.el-nacional.com/ciencia_y_ambiente/Descubren-reaccion-bioquimica-reprogramacion-celulas_0_404359684.html
(EFE) – hace 3 horas
Washington, 7 may (EFE).- Un equipo de científicos del Instituto de Investigación Scripps de California ha incorporado dos nuevas letras al alfabeto genético al desarrollar una bacteria cuyo ADN incluye dos bases nitrogenadas que no se encuentran en la naturaleza.
Así se detalla en un estudio publicado hoy en la versión digital de la revista Nature, en el que se indica que los investigadores consiguieron que las células de la bacteria "Escherichia coli" resultante de la modificación genética se replicaran con relativa normalidad.
"La vida en la Tierra en toda su diversidad está codificada sólo por dos pares de bases de ADN, A-T y C-G", explicó el líder del proyecto, el profesor asociado del Instituto de Investigación Scripps Floyd Romesberg.
Una vez lo lograron, los científicos comprobaron que el material genético de las células se replicaba con razonable velocidad y precisión, no dificultaba el crecimiento de las células de la bacteria y no mostraban signos de perder sus pares de bases no naturales.
http://www.google.com/hostednews/epa/article/ALeqM5iJ0fszP-RkIy4Dz1Kc-J_K_RT9oQ?docId=2312403&hl=es
martes, 4 de febrero de 2014
Humanity's forgotten return to Africa revealed in DNA
20:00 03 February 2014 by Catherine Brahic
For similar stories, visit the Neanderthals , Genetics and Human Evolution Topic Guides
Call it humanity's unexpected U-turn.
One of the biggest events in the history of our species is the exodus out of Africa some 65,000 years ago , the start of Homo sapiens' long march across the world.
Now a study of southern African genes shows that, unexpectedly, another migration took western Eurasian DNA back to the very southern tip of the continent 3000 years ago.
According to conventional thinking, the Khoisan tribes of southern Africa , have lived in near-isolation from the rest of humanity for thousandsof years.
Ancient lineages
"These are very special, isolated populations, carrying what are probably the most ancient lineages in human populations today," says David Reich of Harvard University.
http://www.newscientist.com/article/dn24988-humanitys-forgotten-return-to-africa-revealed-in-dna.html?utm_source=NSNS&utm_medium=SOC&utm_campaign=hoot&cmpid=SOC%7CNSNS%7C2013-GLOBAL-hoot
jueves, 19 de septiembre de 2013
RV: Team finds origin of genome’s ‘dark matter’
Fuente: Futurity
Expuesto el: miércoles, 18 de septiembre de 2013 21:29
Autor: Katrina Voss-Penn State
Asunto: Team finds origin of genome's 'dark matter'
Penn State, Vanderbilt University rightOriginal Study Posted by Katrina Voss-Penn State on September 18, 2013 Non-coding RNA comes from at the same locations along the human genome as coding RNA, researchers have discovered. "Dark matter" does not contain the blueprint for making proteins and yet it makes up more than 95 percent of the human genome. The team's findings eventually may help to pinpoint exactly where complex-disease traits reside, since the genetic origins of many diseases reside outside of the coding region of the genome. B. Franklin Pugh, chair in molecular biology at Penn State, and postdoctoral scholar Bryan Venters, now at Vanderbilt University, performed the research, which appears early online today in Nature. In their research, Pugh and Venters set out to identify the precise location of the beginnings of transcription—the first step in the expression of genes into proteins. "During transcription, DNA is copied into RNA—the single-stranded genetic material that is thought to have preceded the appearance of DNA on Earth—by an enzyme called RNA polymerase and, after several more steps, genes are encoded and proteins eventually are produced," Pugh explains. 'Initiation machines'He adds that, in their quest to learn just where transcription begins, other scientists had looked directly at RNA. However, Pugh and Venters instead determined where along human chromosomes the proteins that initiate transcription of the non-coding RNA were located. "We took this approach because so many RNAs are rapidly destroyed soon after they are made, and this makes them hard to detect," Pugh says. "So rather than look for the RNA product of transcription we looked for the 'initiation machine' that makes the RNA. This machine assembles RNA polymerase, which goes on to make RNA, which goes on to make a protein." Pugh adds that he and Venters were stunned to find 160,000 of these "initiation machines," because humans only have about 30,000 genes. "This finding is even more remarkable, given that fewer than 10,000 of these machines actually were found right at the site of genes. Since most genes are turned off in cells, it is understandable why they are typically devoid of the initiation machinery." The remaining 150,000 initiation machines—those Pugh and Venters did not find right at genes—remained somewhat mysterious. "These initiation machines that were not associated with genes were clearly active since they were making RNA and aligned with fragments of RNA discovered by other scientists," Pugh says. "In the early days, these fragments of RNA were generally dismissed as irrelevant since they did not code for proteins." Pugh adds that it was easy to dismiss these fragments because they lacked a feature called polyadenylation—a long string of genetic material, adenosine bases—that protect the RNA from being destroyed. Not just junkPugh and Venters further validate their surprising findings by determining that these non-coding initiation machines recognized the same DNA sequences as the ones at coding genes, indicating that they have a specific origin and that their production is regulated, just like it is at coding genes. "These non-coding RNAs have been called the 'dark matter' of the genome because, just like the dark matter of the universe, they are massive in terms of coverage—making up over 95 percent of the human genome. However, they are difficult to detect and no one knows exactly what they all are doing or why they are there," Pugh says. "Now at least we know that they are real, and not just 'noise' or 'junk.' Of course, the next step is to answer the question, 'what, in fact, do they do?'" Pugh adds that the implications of this research could represent one step towards solving the problem of "missing heritability"—a concept that describes how most traits, including many diseases, cannot be accounted for by individual genes and seem to have their origins in regions of the genome that do not code for proteins. "It is difficult to pin down the source of a disease when the mutation maps to a region of the genome with no known function," Pugh says. "However, if such regions produce RNA then we are one step closer to understanding that disease." The US National Institutes of Health funded the study. Source: Penn State |
