miércoles, 26 de mayo de 2010
Researchers of the Centre for Genomic Regulation (CRG) demonstrate evidence in support of the common ancestry of life thanks to a new computational approach to study protein evolution.
The study, published in Nature, reveals that protein evolution has not reached its limit and it is still continuing. At the same time, it provides us new information on why this evolution is so slow and conservative showing that protein structures are more evolutionary plastic than previously thought.
Almost 100 years ago Edwin Hubble observed that distant galaxies are moving away from Earth faster than those that are closer. This relationship between distance and velocity is widely cited as evidence of the origin of the Universe from a Big Bang. Researchers at the Centre for Genomic Regulation copied his approach to investigate the divergence between protein sequences.
“We wanted to know if the divergent evolution between proteins was still proceeding. Today, we can find proteins that are still similar after almost 3.5 billion years of evolution. Our study showed that their divergence continues with these proteins becoming more and more different despite their incredible level of conservation”, said Fyodor Kondrashov, principal investigator of the project and leader of the Evolutionary Genomics group at the CRG.
The work done by Fyodor Kondrashov and Inna Povolotskaya goes beyond similarity studies and discusses the evolution of proteins from the view of evolutionary dynamics, offering a new perspective on how protein structures are maintained in evolution. “In the same way that Hubble’s observations led to an understanding of the past and the future of our universe, using his approach at a molecular level we get a similar overview that gives us the ability to analyze evolutionary dynamics and get a broad prediction of the possible changes to the proteins in the future”, says Inna Povolotskaya, first author of the work and responsible for obtaining and analyzing all data.
Proteins are formed through combinations of amino acids, with only 20 types of amino acids are available to form a particular protein. To obtain the data for their study, the CRG researchers have compared proteins sequences from different species that were available in GenBank, a public database of genetic information. Comparing these sequences the authors measured the distance of proteins from each other and devised a method for measuring how fast the proteins are accumulating different changes. Thus, they could replicate Hubble’s approach by correlating the distance between the proteins with the rate of their divergence. The result indicates that even the most distantly-related proteins are still accumulating differences.
The study shows how new techniques of bioinformatics and computational analysis can also expand knowledge at a molecular level. “Our work is a good example of how we can learn new and very fundamental things just by analyzing a larger volume of data that can be obtained by one experimental laboratory”, says Kondrashov.
Most changes in a protein are deleterious because they somehow disrupt its structure or function. The authors observation that even very conservative proteins are still diverging challenges this view, because it implies that most amino acids in a protein can be changes without any ill effects. Their explanation is that amino acid changes that are deleterious in one combination can be benign when occurring in a different one. “Thanks to our study we now have a better understanding of protein structure dynamics” said Kondrashov.
The work of Povolotskaya and Kondrashov also provides new information on how different interactions between different amino acids in the structure of proteins slows down but does not completely prevent evolution.
Tomado de: http://www.biochemist.org/news/page.htm?item=40125
viernes, 21 de mayo de 2010
jueves, 20 de mayo de 2010
Supramolecular architecture explains the incredible strength of fibrin blood clots
A new study unlocks the previously unknown structural features that underlie the incredible elastic resilience of fibrin, the main protein in blood clots. The research, published in Biophysical Journal, provides information on how the molecular architecture of a fibrin network contributes to its resilience and may help to explain what causes the failure of a clot, which can lead to a stroke or heart attack. Fibrin is a fibrous protein which assembles into a remarkably strong spider web-like gel that forms the structural framework of blood clots. Previous work has shown that fibrin networks, thought to be among the most resilient proteins in the natural world, stiffen when deformed and become increasingly resistant to further strain. Although this extraordinary resilience appears to be crucial for the biological function of blood clots, the molecular basis of this resilience is not well understood. “To understand better the superior elasticity of fibrin networks, we measured the mechanical behaviour of purified fibrin gels on multiple scales,” says senior study author, Gijsje H. Koenderink from the Biological Soft Matter Group at the FOM Institute AMOLF in The Netherlands. “We found that the fibrin has a series of molecular domains that are stretched out sequentially, on smaller and smaller scales, when clots are deformed. This stretching leads to gel stiffening, which protects the clots from damage” Specifically, Dr. Koenderink’s group made the surprising discovery that the fibrin fibres are very porous loose bundles of thin filaments that are connected by flexible crosslinkers. This open structure (containing 80% water) makes the fibres 100-fold more flexible than previously thought, and enables sequential stiffening due to straightening out of the bundles between network crosslinks followed by straightening out of flexible protein domains inside the bundles. “We found that it is this bundle-like structure of fibrin fibres that is ultimately responsible for the superior mechanical properties of fibrin gels,” explains Dr. Koenderink. The researchers presented a theoretical model that explained their observations in terms of this unique hierarchical architecture of the fibres. “Our data reveal molecular design principles that allow blood clots to recover from large forces, such as shear forces from blood flow, furthering our understanding of how pathological alterations in fibrin cause clot rupture and bleeding or thrombosis,” concludes Dr. Koenderink. “Moreover, our findings suggest a new design concept for resilient bio-inspired materials with potential applications in drug delivery and tissue repair.” |
martes, 18 de mayo de 2010
Teoría Arqueológica en América del Sur TAAS
Universidad Central de Venezuela, Caracas 21 al 25 de junio de 2010
V Reunión de Teoría Arqueológica en América del SurINVITACIÓN LX CONVENCIÓN ANUAL AsoVAC, CIUDAD BOLÍVAR 2010
lunes, 17 de mayo de 2010
Mucho discurso: pocos hechos
A propósito del Día Mundial de Reciclaje, la organización no gubernamental VITALIS destacó su preocupación porque en Venezuela, del total de alrededor de 18 mil toneladas de residuos que se producen diariamente en el país, pudieran estarse reciclando solamente de 15 a 20% del total de los residuos.
De acuerdo con las estadísticas que maneja VITALIS, en Venezuela se recicla alrededor del 95% del aluminio, 90% de hierro, 25% de vidrio, 1% de materia orgánica, 20% de papel y cartón, y alrededor del 2% en plásticos. Sin embargo, en función del volumen total de residuos, menos de la quinta parte pudieran estar recibiendo un tratamiento final apropiado.
No obstante, la capacidad para reciclar en el país, pudiera duplicarse o triplicarse en el caso del papel, los plásticos y el vidrio, en tanto que el aprovechamiento de los residuos orgánicos pudiera incrementarse hasta un 1000%. Tomando en cuenta que alrededor del 80% de los residuos domésticos e industriales pudieran ser reciclados, no sólo resolveríamos el primer problema ambiental del país que es la basura, sino hasta pudiéramos generar alrededor de 250 mil empleos directos y más de 1 millón indirectos en un año.
* Disminuya la cantidad de basura que genera en casa y reutilice aquellos residuos orgánicos que pueden servir para abonar sus plantas.
* Reutilice lo más posible los envases y demás recipientes en el hogar, el colegio o el trabajo.
* Recicle. Diversas empresas compran vidrio, papel, cartón, plásticos y hasta radiografías médicas.
* Infórmese de los horarios de recolección de basura en su calle o avenida. En caso de no cumplirse, comuníquese con la empresa recolectora y formalice su reclamo.
* Disponga la basura en bolsas herméticamente cerradas. Evite la proliferación de insectos, perros y roedores.
* Evalúe la gestión de su alcalde. En la práctica, el (o ella) es la máxima autoridad ambiental de su municipio y por ende el principal responsable del problema de basura de su localidad.
Reciclar es cualquier proceso donde los residuos o materiales de desperdicio son recolectados y transformados en nuevos materiales que pueden ser utilizados o vendidos como nuevos productos o materias primas. ¿Por qué es importante reciclar? Se pueden salvar grandes cantidades de recursos naturales no renovables cuando en los procesos de producción se utilizan materiales reciclados. Los recursos renovables, como los árboles, también pueden ser salvados. La utilización de productos reciclados disminuye el consumo de energía. Cuando se consuman menos combustibles fósiles, se generará menos CO2 y por lo tanto habrá menos lluvia ácida y se reducirá el efecto invernadero. Venezuela no incentiva suficientemente el reciclaje El 17 de mayo se celebra el Día Mundial del Reciclaje, oportunidad que es festejada en Venezuela sin un plan nacional que articule todos los esfuerzos públicos y privados para resolver muchos de los problemas creados por la inadecuada generación y tratamiento de la basura, que contemple suficientes incentivos para hacer esta actividad atractiva y rentable, sin mencionar sus incalculables beneficios ambientales. Sin embargo, VITALIS aclara que los problemas sociales relacionados con el reciclaje no se solucionan solamente con la educación. Las sociedades tienden a resistirse a los cambios. El ciclo tradicional de adquirir - consumir - desechar es muy difícil de romper. Reciclar en la oficina o en el hogar requiere de un esfuerzo extra para separar los materiales. Siempre parecerá más conveniente el hábito de arrojar todo hacia afuera. ¿Cuánto puede durar la basura al aire libre? 1 año: El papel, compuesto básicamente por celulosa, no le da mayores problemas a la naturaleza para integrar sus componentes al suelo. Si queda tirado sobre tierra y le toca un invierno lluvioso, no tarda en degradarse. Lo ideal, de todos modos, es reciclarlo para evitar que se sigan talando árboles para su fabricación. |
La revolución virtual: 20 años de la web
Hace dos décadas el británico Tim Berners-Lee inventó la web "sólo porque la necesitaba", según le dijo a la BBC. A partir de entonces, el mundo no volvió a ser igual.
“Que veinte años no es nada…” cantaba Carlos Gardel en su entrañable tango “Volver”. Y tal vez en pocos episodios de la historia mundial es tan apropiada esta expresión como en el vertiginoso desarrollo de la red global de internet en las dos últimas décadas.
La World Wide Web, o la “red”, transformó de tal manera la sociedad global que muchos no dudan en compararla con la Revolución Industrial del siglo XIX.
Y es que cada vez son menos los sectores de la sociedad que no han sido tocados de una manera u otra por el explosivo crecimiento del mundo "en línea". Aunque las cifras varían, algunos estudios calculan que cerca de 1.700 millones de personas, o sea casi el 25% de la población mundial, son usuarias del universo de la red.
http://www.bbc.co.uk/mundo/ciencia_tecnologia/2010/03/100305_web_especial_dos_decadas.shtmlviernes, 14 de mayo de 2010
MATERIALES NANOESTRUCTURADOS: SÍNTESIS, CARACTERIZACIÓN Y PROPIEDADES
jueves, 13 de mayo de 2010
lunes, 10 de mayo de 2010
The Gordon Research Conference (GRC) on Membrane Transport Proteins
University of New England
Biddeford,Maine, USA
will be held for the 7th time and continue to bring together researchers from many different areas in the field of membrane transport. It is a major goal of the conference to bring together people who do not normally interact and to ensure participation of as many students, post docs and young investigators as possible.
Congreso de la Unión Internacional de Ciencias Antropológicas y Etnológicas
El Congreso de la IUAES tendrá lugar los días 3-6 de Octubre del 2010 en la ciudad turca de Antalya
Se pueden enviar propuestas de ponencias desde el 15 de abril al 1 de julio del 2010. Las propuestas han de enviarse por correo electrónico al comité de la organización. Los autores de las propuestas aceptadas serán notificados el 1 de agosto 2010.
Para más información ir a http://www.iuaes2010.org/
viernes, 7 de mayo de 2010
Mother-infant bonds predicted by hormone levels in humans and other mammals
Image: "Mother's Love" by Kolongi Brathwaite
A common tactic by evolution deniers is to claim that if a complex behavior can’t be measured than the scientific method must be a flawed approach towards understanding the world. Nevermind that no one challenges the science of physics just because we can’t predict the complex motions of a leaf in a windstorm. But when it comes to matters of emotion somehow natural explanations are off limits. This is readily apparent in the common argument that, “if you think biology is such a good explanation of behavior, then prove that your mother loves you.” However, as it turns out, we can address this challenge of motherly love and demonstrate a plausible scientific explanation by measuring the levels of the important hormones involved.
Writing in the current issue of Psychological Science (subscription required), Ruth Feldman and colleagues at the Gonda Brain Research Center at Bar-Ilan University in Israel have found evidence that neuroendocrine levels of the hormone oxytocin is a strong predictor of a mother’s bond with her infant. By sampling the blood oxytocin levels of 62 pregnant women (of all educational and employment backgrounds) the researchers found that oxytocin levels remained consistent throughout their pregnancy but differed substantially between the women. By then analyzing video footage of the mothers’ interactions with their infants (which included analysis of how often they gazed at the infant’s face, their amount of affectionate touching, rocking, and how often they spoke in motherese to their child) the researchers found that levels of oxytocin was the major factor in predicting the levels of maternal bonding.
As the authors reported in their study:
The results suggest that the neuroendocrine system associated with bond formation in mammals may play a similar role in humans. OT [oxytocin] was found to be related to a well-defined cluster of maternal behaviors, attachment representations, and a specific maternal behavior that appears across mammalian species . . . These findings lend support to ethological and evolutionary perspectives on human bonding.
Macaque mother with nursing infant.
Image: Paula Bronstein/Getty Images
In other words, for all mammals there’s evidence that high levels of oxytocin translate into a feeling of personal attachment with their infant. Earlier studies on oxytocin have shown that the hormone is also involved in pair-bonding and cooperative behavior. For example in the closely related prairie and meadow voles, the former is a pair-bonded species that shows high levels of both maternal and paternal care while the latter are neither pair-bonded nor attentive to their offspring. Work carried out by Thomas Insel at Emory University has shown that oxytocin receptor density is the primary difference between the two species.
As to why some individual’s have high oxytocin levels and others don’t is still an open question. Research on primates and rats has shown that daughters who grew up feeling safe and secure with high levels of parental investment demonstrated the same parental behavior with their offspring. It’s likely that a safe and nurturing environment (with both economic and social support for the mother) would increase a mother’s oxytocin levels and could thereby increase the amount of maternal bonding.
However, it’s important to point out that there is not one “optimal” maternal behavior for all environments. Human mothers respond to their surroundings in the same way that other species do. Whether you’re a mouse living in desert landscape or a woman in an impoverished city center, if an environment is particularly harsh it may well be more adaptive for mothers to show less maternal bonding and thereby raise an infant who will be hardened for a difficult life. It’s also important to point out that while these results are highly significant, there is more than just chemistry that influences a mother’s love. We shouldn’t underemphasize the personal decisions or the cultural influences that a woman encounters that influence her maternal behavior. To do so would be to miss the larger picture and not show our full appreciation for the sacrifices that mothers make.
While many interactions are likely to be involved in maternal behavior (both hormonal and social), this study shows that a mother’s love can be partly quantified and predicted using the tools of the scientific method. More than a final retort to my hypothetical interrogator, what this study shows is how remarkably conservative and elegant the products of natural selection can be. To think that a single hormone is identical across mammalian species and can influence one of the most profound feelings imaginable is an awe inspiring thought. To cop a quote from Darwin himself, there truly is “grandeur in this view of life.”
Reference:
Ruth Feldman, Aron Weller, Orna Zagoory-Sharon and Ari Levine (2007). Evidence for a neuroendocrinological foundation of human affiliation: plasma oxytocin levels across pregnancy and the postpartum period predict mother-infant bonding. Psychological Science 18(11):965-970. doi:10.1111/j.1467-9280.2007.02010.x
martes, 4 de mayo de 2010
ACSM conference on Integrative Physiology of Exercise (IPE)
September 22-25Integrated Physiology of Exercise Meeting, Miami Beach, FL
Call for Abstracts: American College of Sports Medicine Conference on Integrative Physiology of Exercise
Topics include:
- Discovery and application of integrative exercise physiology: adaptation & performance
- Exercise metabolism: mitochondrial dynamics and substrate regulation
- Exercise, oxidative stress and redox signaling
- Cardiovascular regulation and adaptation during exercise
Abstract Deadline - July 12, 2010
lunes, 3 de mayo de 2010
Postdoctoral Position – Cardiovascular Physiology | |||||
A Canadian Institutes of Health Research supported postdoctoral position is available in the laboratory of Dr. Robert Rose at Dalhousie University where we are performing cardiac electrophysiology experiments. A variety of techniques are utilized in the laboratory including patch-clamping of isolated cardiomyocytes, in vivo electrocardiography (body surface and intracardiac), optical mapping using voltage sensitive dyes, and molecular biology. A background in cardiac electrophysiology is required. Experience using intracardiac electrophysiology catheters or with high speed optical imaging is highly desired. Salary is commensurate with experience and based on current CIHR guidelines. Applicants should have a PhD degree and send a cover letter, CV and the names/contact information for 2-3 references to: Robert A. Rose, PhD, Department of Physiology and Biophysics, Dalhousie University, Sir Charles Tupper Medical Building, 5850 College Street, Halifax, Nova Scotia, Canada, B3H 1X5. | |||||
Contact | Robert A. Rose, PhD | ||||
robert.rose@dal.ca | |||||
Posted | Mar 10 2010 | ||||
Applications accepted on an ongoing basis. |
- Macrophages in Inflammation - IRBB
25-27 Octubre 2010
Parc Científic de Barcelona - IRBB
C/ Baldiri Reixac 10
Barcelona
Organizado por:
Antonio Celada - Alberto Mantovani
Contacto:
Antonio Celada
info@irbbarcelona.org
Más información:
http://www.irbbarcelona.org/biomed/macrophages
Macrophages in Inflammation
The 11th International Congress of the Immunology of Diabetes Society
Dated: October 31(Sun) - November 3(Wed), 2010
Venue: | Songdo Conventia - Ballroom (Meeting Place) |
Sheraton Incheon - Main accomodation | |
Best Western Premier Songdo Park Hotel (accomodation) | |
BENKIA Premier Songdo Metro Hotel (accomodation) |
http://www.ids2010.kr/ |