Escribo para mí, para recordar algunas ideas que me interesan. Con el tiempo he descubierto que existe más o menos un nexo común en esas ideas. Aviso: Este blog no es un consultorio de salud.
Mostrando entradas con la etiqueta cooperación. Mostrar todas las entradas
Mostrando entradas con la etiqueta cooperación. Mostrar todas las entradas
jueves, 13 de agosto de 2015
martes, 10 de marzo de 2015
Bacterias que se axudan facendo nanopontes
Audio en galego. A nosa sección "Circo de Bacterias" a partires do minuto 40:30
viernes, 10 de agosto de 2012
Bacterioides fragilis, una historia de mutualismo entre humanos y bacterias
Bacterioides fragilis es una bacteria común, presente en el 75% de las personas. Cumple una importante misión que nuestro propio ADN no nos proporciona: nos ayuda a a funcionar nuestro sistema inmunitario. Esta bacteria, como muchas otras, tiene una "cubierta" de moco que no es otra cosa que cadenas de azúcares. Una de estas cadenas se llama polisacárido A. El polisacárido A de Bacterioides fragilis es una señal que le sirve a nuestro sistema inmune para producir un tipo de célula del sistema que se llama linfocito T regulador. Antes de seguir voy a explicar un poco cómo funciona el sistema inmune. El sistema inmune humano consta de varios tipos de células que le sirven para atacar a todo cuerpo ajeno al nuestro, como bacterias y virus. Son células que están entrenadas para respetar a nuestras células y destruir a las que considera ajenas. Los linfocitos T identifican y atacan a los invasores microbianos al tiempo que provocan hinchazón, aumento de temperatura, características típicas de la respuesta inflamatoria que se produce después de una infección. Entonces, si hay infección, por entrada de bacterias en nuestro cuerpo, el sistema inmune comienza a producir linfocitos T. El problema es que los linfocitos proinflamatorios han "nasío pa matá" y para eliminar a los agentes causantes de la infección no dudan en liberar compuestos tóxicos que terminarían destruyendo a nuestros propios tejidos. Para evitar eso, el sistema inmune produce los linfocitos T reguladores con el objeto de contrarrestar la actividad de los linfocitos T proinflamatorios.
Se había observado que los ratones sin bacterias de laboratorio poseían un sistema inmunitario defectuoso, con una función reducida de los linfocitos T reguladores. Cuando se introdujo B. fragilis en estos ratones de laboratorio, el equilibrio entre los linfocitos T proinflamatorios y reguladores se restauró y su sistema inmunológico comenzó a funcionar con normalidad.
B. fragilis, a diferencia de los microorganismos patógenos capaces de modular nuestro sistema inmune en su benefició, ayuda al sistema a funcionar correctamente.
Por desgracia, debido al exceso de higiene la relación de los humanos con B. fragilis se ha modificado. Según Sarkis K. Mazmanian, del CALTECH: "En nuestro esfuerzo por distanciarnos de los agentes infecciosos que nos provocan enfermedades, hemos alterado la relación con los microorganismos que nos resultan útiles. Nuestras intenciones son buenas, pero hay un precio que pagar. Mazmanian sostiene que el aumento reciente de entre siete y ocho veces en la frecuencia de los transtornos autoinmunes, como la enfermedad de Crohn, la diabetes de tipo 1 y la esclerosis múltiple, guarda relación con la disminución de los microorganismos beneficiosos, es decir, que la pérdida de la flora microbiana en los humanos ha hecho disparar la frecuencia de las enfermedades autoinmunitarias e incluso de la obesidad.
lunes, 23 de enero de 2012
Ciencia en comunidad: foldit
Me encanta esta idea del Foldit: un concurso para resolver la estructura tridimensional de una proteínas hecha por aficionados. Más divertido y más difícil que el sudoko, pero de infinitísima más utilidad.
miércoles, 28 de abril de 2010
Co-evolution: Cooperation & Aggressive Symbiosis
Escrito por Nina Munteanu, SF writer and Ecologist
Tuesday, August 7, 2007
Most impediments to scientific understanding are conceptual locks, not factual lacks...We know ourselves best and tend to view other creatures as mirrors of our own constitution and social arrangements.
—Stephen Jay Gould, Bully for Brontosaurus
The evolution of species naturally arises from its response to its landscape, climate, access to shelter and nourishment, as well as the nature of its interaction with its community (e.g., competition and cooperation).
In a previous post of mine, I discussed the phenomenon called “endosymbiosis” by Dr. Lynn Margulis, who suggested a cellular evolution based on ‘cooperation’ rather than simple ‘competition’ between viral or bacterial infection and host cell. This co-evolutionary behaviour runs counter to the traditional route of natural selection and contradicts the ruthless selfishness of Darwinian thinking. Such an evolving relationship between two different species of life, living together in a very close affinity of mutual benefit is common in nature.
Let's take a look at the simple virus: the ecological "home" of the virus is the genome of any potential host and scientists have remained baffled by the overwhelming evidence for ‘accomodation’; a virus initially very aggressive, may exhibit less aggression toward an evolution of partnership.
Co-evolution was first proposed by Ehrlich and Raven in 1964 to explain the parallel evolution of butterflies and their host plants. Virologist, Frank Ryan calls it “a wonderful marriage in nature—a partnership in which the definition of predator and prey blurs, until it seems to metamorphose to something altogether different.” Co-evolution is now an established theme in the biology of virus-host relationships. Relationships span from the complex interaction between arboviruses and their vector mosquitoes to the one between the malaria-causing plasmodium and humans or the hantavirus and the deer mouse.
Ryan states that “today...every monkey, baboon, chimpanzee and gorilla is carrying at least ten different species of symbiotic viruses.”
“Why,” asks Dr. Frank Ryan, “is co-evolution [and its partner, symbiosis] such a common pattern in nature?” Ryan coined the term “genomic intelligence” to explain the form of intelligence exerted by viruses and the capacity of the genome to be both receptive and responsive to nature. It involves an incredible interaction between the genetic template and nature that governs even viruses. Symbiosis and natural selection need not be viewed as mutually contradictory. Russian biologists, Andrei Famintsyn and Konstantine Merezhkovskii invented the term “symbiogenesis” to explain the fantastic synthesis of new living organisms from symbiotic unions. Citing the evolution of mitochondria and the chloroplast within a primitive host cell to form the more complex eukaryotic cell (as originally theorized by Lynn Margulis), Ryan noted that “it would be hard to imagine how the step by step gradualism of natural selection could have resulted in this brazenly passionate intercourse of life!”
In his book, “Virus X” Dr. Frank Ryan coined the term “aggressive symbiont” to explain a common form of symbiosis where one or both symbiotic partners demonstrates an aggressive and potentially harmful effect on the other’s competitor or potential predator. Examples abound, but a few are worth mentioning here. In the South American forests, a species of acacia tree that produces a waxy berry of protein at the ends of their leaves that provides nourishment for the growing infants of the ant colony residing in the tree. The ants, in turn not only keep the foliage clear of herbivores and preying insects through a stinging assault, but they make hunting forays into the wilderness of the tree, destroying the growing shoots of potential rivals to the acacia. Viruses commonly form “aggressive symbiotic” relationships with their hosts, one example of which is the herpes-B virus, Herpesvirus saimiri, and the squirrel monkey (the virus induces cancer in the competing marmoset monkey). Ryan suggests that the Ebola and hantavirus outbreaks follow a similar pattern of “aggressive symbiosis”.
The historian, William H. McNeill, suggested that a form of “aggressive symbiosis” played a key role in the history of human civilization. “At every level of organization—molecular, cellular, organismic, and social—one confronts equilibrium [symbiotic] patterns. Within such equilibria, any alteration from ‘outside’ tends to provoke compensatory changes [aggressive symbiosis] throughout the system to minimize overall upheaval.” One of a legacy of examples of aggressive symbiosis in history includes smallpox: presumably in the process of symbiotic adaptation through co-evolution with the Europeans, they introduced it to the Aztecs with devastating results. Other examples include measles, malaria, and yellow fever.
Well, this puts a whole new twist on the concept of encroachment and development, doesn't it?...
Tuesday, August 7, 2007
Most impediments to scientific understanding are conceptual locks, not factual lacks...We know ourselves best and tend to view other creatures as mirrors of our own constitution and social arrangements.
—Stephen Jay Gould, Bully for Brontosaurus
The evolution of species naturally arises from its response to its landscape, climate, access to shelter and nourishment, as well as the nature of its interaction with its community (e.g., competition and cooperation).
In a previous post of mine, I discussed the phenomenon called “endosymbiosis” by Dr. Lynn Margulis, who suggested a cellular evolution based on ‘cooperation’ rather than simple ‘competition’ between viral or bacterial infection and host cell. This co-evolutionary behaviour runs counter to the traditional route of natural selection and contradicts the ruthless selfishness of Darwinian thinking. Such an evolving relationship between two different species of life, living together in a very close affinity of mutual benefit is common in nature.
Let's take a look at the simple virus: the ecological "home" of the virus is the genome of any potential host and scientists have remained baffled by the overwhelming evidence for ‘accomodation’; a virus initially very aggressive, may exhibit less aggression toward an evolution of partnership.
Co-evolution was first proposed by Ehrlich and Raven in 1964 to explain the parallel evolution of butterflies and their host plants. Virologist, Frank Ryan calls it “a wonderful marriage in nature—a partnership in which the definition of predator and prey blurs, until it seems to metamorphose to something altogether different.” Co-evolution is now an established theme in the biology of virus-host relationships. Relationships span from the complex interaction between arboviruses and their vector mosquitoes to the one between the malaria-causing plasmodium and humans or the hantavirus and the deer mouse.
Ryan states that “today...every monkey, baboon, chimpanzee and gorilla is carrying at least ten different species of symbiotic viruses.”
“Why,” asks Dr. Frank Ryan, “is co-evolution [and its partner, symbiosis] such a common pattern in nature?” Ryan coined the term “genomic intelligence” to explain the form of intelligence exerted by viruses and the capacity of the genome to be both receptive and responsive to nature. It involves an incredible interaction between the genetic template and nature that governs even viruses. Symbiosis and natural selection need not be viewed as mutually contradictory. Russian biologists, Andrei Famintsyn and Konstantine Merezhkovskii invented the term “symbiogenesis” to explain the fantastic synthesis of new living organisms from symbiotic unions. Citing the evolution of mitochondria and the chloroplast within a primitive host cell to form the more complex eukaryotic cell (as originally theorized by Lynn Margulis), Ryan noted that “it would be hard to imagine how the step by step gradualism of natural selection could have resulted in this brazenly passionate intercourse of life!”
In his book, “Virus X” Dr. Frank Ryan coined the term “aggressive symbiont” to explain a common form of symbiosis where one or both symbiotic partners demonstrates an aggressive and potentially harmful effect on the other’s competitor or potential predator. Examples abound, but a few are worth mentioning here. In the South American forests, a species of acacia tree that produces a waxy berry of protein at the ends of their leaves that provides nourishment for the growing infants of the ant colony residing in the tree. The ants, in turn not only keep the foliage clear of herbivores and preying insects through a stinging assault, but they make hunting forays into the wilderness of the tree, destroying the growing shoots of potential rivals to the acacia. Viruses commonly form “aggressive symbiotic” relationships with their hosts, one example of which is the herpes-B virus, Herpesvirus saimiri, and the squirrel monkey (the virus induces cancer in the competing marmoset monkey). Ryan suggests that the Ebola and hantavirus outbreaks follow a similar pattern of “aggressive symbiosis”.
The historian, William H. McNeill, suggested that a form of “aggressive symbiosis” played a key role in the history of human civilization. “At every level of organization—molecular, cellular, organismic, and social—one confronts equilibrium [symbiotic] patterns. Within such equilibria, any alteration from ‘outside’ tends to provoke compensatory changes [aggressive symbiosis] throughout the system to minimize overall upheaval.” One of a legacy of examples of aggressive symbiosis in history includes smallpox: presumably in the process of symbiotic adaptation through co-evolution with the Europeans, they introduced it to the Aztecs with devastating results. Other examples include measles, malaria, and yellow fever.
Well, this puts a whole new twist on the concept of encroachment and development, doesn't it?...
Suscribirse a:
Entradas (Atom)