EXPERIMENTO A BORDO DEL ATLANTIS
El espacio triplica la virulencia de algunas bacterias
La astronauta responsable del proyecto con el recipiente de las bacterias (Foto: PNAS)
Actualizado martes 25/09/2007 10:31 (CET)
ÁNGEL DÍAZ
MADRID.- Vivir en el espacio puede ser complicado para los astronautas, quienes pierden durante sus misiones masa ósea y muscular, están expuestos a la radiación cósmica, se desorientan con facilidad y a veces se deprimen por el aislamiento, entre otros problemas. Pero para bacterias como la Salmonella, causante de un gran número de intoxicaciones alimentarias en todo el mundo, la ausencia de gravedad tiene otra clase de efectos: los vuelve más virulentos.
Tal ha sido el resultado del primer estudio realizado durante un viaje espacial para estudiar los cambios genéticos que éste provoca en la capacidad infecciosa de un microorganismo.
La investigación, que se publica hoy en Proceedings of the National Academy of Sciences (PNAS), se llevó a cabo con bacterias de Salmonella herméticamente cerradas en un recipiente especial, durante el vuelo del transbordador Atlantis de septiembre de 2006.
Esta misión fue importante porque sirvió para reanudar la construcción de la ISS, paralizada tras el accidente mortal del Columbia. Pero la astronauta Heidemarie Stefanyshyn-Piper, de la NASA, aprovechó también para llevar a cabo el experimento de la Salmonella, dirigido desde el Instituto de Biodiseño de la Universidad Estatal de Arizona. Los cultivos de Salmonella typhimurium, causante de la salmonelosis, viajaron a la órbita terrestre en un pequeño cilindro compartimentado y reforzado con triples medidas de seguridad para no infectar a la tripulación.
Crecer a sus anchas
Llegado el momento, la astronauta activó un mecanismo (en la imagen) que permitía a las bacterias acceder a la parte del recipiente donde podían crecer a sus anchas, para ver cómo se comportaban en ausencia de gravedad. Simultáneamente, en la Tierra se hizo un experimento idéntico, para comparar ambos cultivos de Salmonella.
A la vuelta de la misión, los científicos analizaron las bacterias y descubrieron que hasta 167 genes de las que habían viajado al espacio funcionaban de forma distinta a sus hermanas terrestres. Estos cambios en la expresión génica hicieron que la Salmonella astronauta fuese tres veces más virulenta, es decir, tuviese el triple de capacidad de contagiarse a las personas.
Los investigadores también identificaron una proteína, llamada Hfq, que parece ser la causante del aumento de la virulencia, por lo que podría convertirse en el objetivo idóneo contra el que desarrollar una vacuna para la Salmonella, algo que en la actualidad no existe. Además, el experimento ha mostrado que las bacterias más peligrosas forman una película que las hace más resistentes a los ataques del sistema inmune, lo que quizás ayude a explicar por qué la Salmonella es cada vez más resistente a los antibióticos.
martes, 25 de septiembre de 2007
lunes, 24 de septiembre de 2007
Hurricane. Bob Dylan
Pistol shots ring out in the barroom night
Enter Patty Valentine from the upper hall.
She sees the bartender in a pool of blood,
Cries out, "My God, they killed them all!"
Here comes the story of the Hurricane,
The man the authorities came to blame
For somethin' that he never done.
Put in a prison cell, but one time he could-a been
The champion of the world.
Three bodies lyin' there does Patty see
And another man named Bello, movin' around mysteriously.
"I didn't do it," he says, and he throws up his hands
"I was only robbin' the register, I hope you understand.
I saw them leavin'," he says, and he stops
"One of us had better call up the cops."
And so Patty calls the cops
And they arrive on the scene with their red lights flashin'
In the hot New Jersey night.
Meanwhile, far away in another part of town
Rubin Carter and a couple of friends are drivin' around.
Number one contender for the middleweight crown
Had no idea what kinda shit was about to go down
When a cop pulled him over to the side of the road
Just like the time before and the time before that.
In Paterson that's just the way things go.
If you're black you might as well not show up on the street
'Less you wanna draw the heat.
Alfred Bello had a partner and he had a rap for the cops.
Him and Arthur Dexter Bradley were just out prowlin' around
He said, "I saw two men runnin' out, they looked like middleweights
They jumped into a white car with out-of-state plates."
And Miss Patty Valentine just nodded her head.
Cop said, "Wait a minute, boys, this one's not dead"
So they took him to the infirmary
And though this man could hardly see
They told him that he could identify the guilty men.
Four in the mornin' and they haul Rubin in,
Take him to the hospital and they bring him upstairs.
The wounded man looks up through his one dyin' eye
Says, "Wha'd you bring him in here for? He ain't the guy!"
Yes, here's the story of the Hurricane,
The man the authorities came to blame
For somethin' that he never done.
Put in a prison cell, but one time he could-a been
The champion of the world.
Four months later, the ghettos are in flame,
Rubin's in South America, fightin' for his name
While Arthur Dexter Bradley's still in the robbery game
And the cops are puttin' the screws to him, lookin' for somebody to blame.
"Remember that murder that happened in a bar?"
"Remember you said you saw the getaway car?"
"You think you'd like to play ball with the law?"
"Think it might-a been that fighter that you saw runnin' that night?"
"Don't forget that you are white."
Arthur Dexter Bradley said, "I'm really not sure."
Cops said, "A poor boy like you could use a break
We got you for the motel job and we're talkin' to your friend Bello
Now you don't wanta have to go back to jail, be a nice fellow.
You'll be doin' society a favor.
That sonofabitch is brave and gettin' braver.
We want to put his ass in stir
We want to pin this triple murder on him
He ain't no Gentleman Jim."
Rubin could take a man out with just one punch
But he never did like to talk about it all that much.
It's my work, he'd say, and I do it for pay
And when it's over I'd just as soon go on my way
Up to some paradise
Where the trout streams flow and the air is nice
And ride a horse along a trail.
But then they took him to the jailhouse
Where they try to turn a man into a mouse.
All of Rubin's cards were marked in advance
The trial was a pig-circus, he never had a chance.
The judge made Rubin's witnesses drunkards from the slums
To the white folks who watched he was a revolutionary bum
And to the black folks he was just a crazy nigger.
No one doubted that he pulled the trigger.
And though they could not produce the gun,
The D.A. said he was the one who did the deed
And the all-white jury agreed.
Rubin Carter was falsely tried.
The crime was murder "one," guess who testified?
Bello and Bradley and they both baldly lied
And the newspapers, they all went along for the ride.
How can the life of such a man
Be in the palm of some fool's hand?
To see him obviously framed
Couldn't help but make me feel ashamed to live in a land
Where justice is a game.
Now all the criminals in their coats and their ties
Are free to drink martinis and watch the sun rise
While Rubin sits like Buddha in a ten-foot cell
An innocent man in a living hell.
That's the story of the Hurricane,
But it won't be over till they clear his name
And give him back the time he's done.
Put in a prison cell, but one time he could-a been
The champion of the world.
Enter Patty Valentine from the upper hall.
She sees the bartender in a pool of blood,
Cries out, "My God, they killed them all!"
Here comes the story of the Hurricane,
The man the authorities came to blame
For somethin' that he never done.
Put in a prison cell, but one time he could-a been
The champion of the world.
Three bodies lyin' there does Patty see
And another man named Bello, movin' around mysteriously.
"I didn't do it," he says, and he throws up his hands
"I was only robbin' the register, I hope you understand.
I saw them leavin'," he says, and he stops
"One of us had better call up the cops."
And so Patty calls the cops
And they arrive on the scene with their red lights flashin'
In the hot New Jersey night.
Meanwhile, far away in another part of town
Rubin Carter and a couple of friends are drivin' around.
Number one contender for the middleweight crown
Had no idea what kinda shit was about to go down
When a cop pulled him over to the side of the road
Just like the time before and the time before that.
In Paterson that's just the way things go.
If you're black you might as well not show up on the street
'Less you wanna draw the heat.
Alfred Bello had a partner and he had a rap for the cops.
Him and Arthur Dexter Bradley were just out prowlin' around
He said, "I saw two men runnin' out, they looked like middleweights
They jumped into a white car with out-of-state plates."
And Miss Patty Valentine just nodded her head.
Cop said, "Wait a minute, boys, this one's not dead"
So they took him to the infirmary
And though this man could hardly see
They told him that he could identify the guilty men.
Four in the mornin' and they haul Rubin in,
Take him to the hospital and they bring him upstairs.
The wounded man looks up through his one dyin' eye
Says, "Wha'd you bring him in here for? He ain't the guy!"
Yes, here's the story of the Hurricane,
The man the authorities came to blame
For somethin' that he never done.
Put in a prison cell, but one time he could-a been
The champion of the world.
Four months later, the ghettos are in flame,
Rubin's in South America, fightin' for his name
While Arthur Dexter Bradley's still in the robbery game
And the cops are puttin' the screws to him, lookin' for somebody to blame.
"Remember that murder that happened in a bar?"
"Remember you said you saw the getaway car?"
"You think you'd like to play ball with the law?"
"Think it might-a been that fighter that you saw runnin' that night?"
"Don't forget that you are white."
Arthur Dexter Bradley said, "I'm really not sure."
Cops said, "A poor boy like you could use a break
We got you for the motel job and we're talkin' to your friend Bello
Now you don't wanta have to go back to jail, be a nice fellow.
You'll be doin' society a favor.
That sonofabitch is brave and gettin' braver.
We want to put his ass in stir
We want to pin this triple murder on him
He ain't no Gentleman Jim."
Rubin could take a man out with just one punch
But he never did like to talk about it all that much.
It's my work, he'd say, and I do it for pay
And when it's over I'd just as soon go on my way
Up to some paradise
Where the trout streams flow and the air is nice
And ride a horse along a trail.
But then they took him to the jailhouse
Where they try to turn a man into a mouse.
All of Rubin's cards were marked in advance
The trial was a pig-circus, he never had a chance.
The judge made Rubin's witnesses drunkards from the slums
To the white folks who watched he was a revolutionary bum
And to the black folks he was just a crazy nigger.
No one doubted that he pulled the trigger.
And though they could not produce the gun,
The D.A. said he was the one who did the deed
And the all-white jury agreed.
Rubin Carter was falsely tried.
The crime was murder "one," guess who testified?
Bello and Bradley and they both baldly lied
And the newspapers, they all went along for the ride.
How can the life of such a man
Be in the palm of some fool's hand?
To see him obviously framed
Couldn't help but make me feel ashamed to live in a land
Where justice is a game.
Now all the criminals in their coats and their ties
Are free to drink martinis and watch the sun rise
While Rubin sits like Buddha in a ten-foot cell
An innocent man in a living hell.
That's the story of the Hurricane,
But it won't be over till they clear his name
And give him back the time he's done.
Put in a prison cell, but one time he could-a been
The champion of the world.
Ojos de hielo
No importa que hoy no haya salido el sol
me hace sentir que tu luz es mas fuerte
da igual que no utilices la razon
porque nunca te ha faltado suerte
Escucha, se que no debes pensar porque he tardado tanto en conocerte
tu sabes que no se aprende a volar tan facilmente
y que ademas el viento nunca miente...
Y no volver a pasar delante de tu mirada,
puedes hacerme temblar
y no quiero ver tus ojos de hielo llorar...
Parece que los artistas no te van
parece que hay tipos con mucha mas suerte
me invento mil formas de arreglar las cosas,
pero se me olvido que somos dos...
que somos dos...
Y no volver a pasar delante de tu mirada puedes hacerme temblar
y no quiero ver tus ojos de hielo...llorar
me hace sentir que tu luz es mas fuerte
da igual que no utilices la razon
porque nunca te ha faltado suerte
Escucha, se que no debes pensar porque he tardado tanto en conocerte
tu sabes que no se aprende a volar tan facilmente
y que ademas el viento nunca miente...
Y no volver a pasar delante de tu mirada,
puedes hacerme temblar
y no quiero ver tus ojos de hielo llorar...
Parece que los artistas no te van
parece que hay tipos con mucha mas suerte
me invento mil formas de arreglar las cosas,
pero se me olvido que somos dos...
que somos dos...
Y no volver a pasar delante de tu mirada puedes hacerme temblar
y no quiero ver tus ojos de hielo...llorar
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