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sábado, 24 de febrero de 2024

Mapa de vías metabólicas

 Qué está sucediendo en tu cuerpo ahora mismo? Tu primera respuesta podría ser que tienes hambre o que tus músculos están adoloridos después de una carrera o que estás cansado.

Mapa de vías metabólicas ¡Gratis! en alta resolución. (comunidad-biologica.com)

Pero para apreciar realmente la maravilla de la vida, necesitamos sumergirnos en un mundo que trasciende nuestra consciencia cotidiana, veamos qué está pasando en nuestras células.

Al observar detenidamente cualquier célula de tu cuerpo, descubrirías un epicentro de actividad frenética, comparable a un mercado bullicioso en pleno ajetreo, muy lejos de la tranquilidad de una habitación vacía.

Cada célula en nuestro cuerpo es un microcosmos repleto de procesos fisiológicos vitales. Dentro de cada una, se desarrollan continuamente reacciones bioquímicas esenciales para nuestra existencia.


Leer más: La Universidad de Harvard ofrece más de 140 cursos online gratis.


Independientemente de si estás en un estado de vigilia o sueño, ya sea corriendo o relajándote frente a la televisión, en el interior de tus células ocurre una transformación energética constante y dinámica.

En este micro-universo celular, las moléculas orgánicas como los azúcares, lípidos y proteínas no son meros espectadores, sino protagonistas activos.

En la vía de la glucólisis, por ejemplo, la glucosa se descompone en unidades más pequeñas, liberando energía en forma de ATP, la moneda energética de la célula.

Este constante intercambio de materiales y energía, que se lleva a cabo en el escenario microscópico de tus células, es lo que te permite responder a estímulos, crecer, adaptarte y, en última instancia, vivir.

Mapa de vías metabólicas

El metabolismo es un conjunto de procesos químicos vitales que ocurren en los seres vivos para mantener la vida. Estos procesos permiten a los organismos crecer, reproducirse, mantener sus estructuras y responder al ambiente.

A continuación, se ofrece una visión general del metabolismo, abordando sus componentes clave y su significado biológico… El metabolismo se divide en dos procesos interconectados: catabolismo y anabolismo.

Catabolismo

  1. Descomposición de Moléculas:
    • Procesos como la glucólisis, el ciclo del ácido cítrico y la fosforilación oxidativa descomponen nutrientes como glucosa y ácidos grasos para producir energía.
    • La glucólisis, que ocurre en el citosol, convierte la glucosa en piruvato, generando ATP y NADH. El piruvato luego ingresa a las mitocondrias para el ciclo del ácido cítrico y la cadena de transporte de electrones, produciendo una cantidad significativa de ATP.
  2. Generación de Metabolitos:
    • Estos procesos también producen metabolitos intermediarios, que son esenciales para otras rutas metabólicas, como la biosíntesis.

Anabolismo

  1. Síntesis de Macromoléculas:
    • Involucra la construcción de proteínas, ácidos nucleicos, lípidos y carbohidratos. Estas vías usan ATP y metabolitos generados por el catabolismo.
    • Por ejemplo, la síntesis de proteínas en los ribosomas, donde los aminoácidos se ensamblan en polipéptidos según las instrucciones del ARN mensajero.
  2. Utilización de Energía:
    • A diferencia del catabolismo, el anabolismo consume energía, subrayando su naturaleza biosintética.

Regulación Metabólica

El metabolismo está finamente regulado para mantener la homeostasis celular.

Referencia: Nelson, D. L., & Cox, M. M. (2022). Princípios de bioquímica de Lehninger. Artmed Editora

viernes, 16 de febrero de 2024

Stop This Absurd War on the Color Pink

 

Last week Robert Krulwich, a co-host of the wonderful program Radiolab, Pluto'd pink. In a blog post he noted that pink doesn't occupy a slot in the familiar colors of the rainbow—there's no P in Roy G. Biv. From this, he concludes that pink does not really exist:

That's why pink is an invention. It's not a name we give to something out there. Pink isn't out there.

Es cierto que no hay una sola longitud de onda de luz que sea rosa. El rosa requiere una mezcla de luz roja y púrpura, colores de extremos opuestos del espectro visible. Es fácil de hacer y no parece amenazar el estatus ontológico del rosa. (Aunque esta propiedad implica que las leyes del universo han conspirado contra los láseres rosas).

El problema comienza cuando Krulwich imagina el espectro visible curvándose en un círculo, con el rosa como el trozo que falta entre el rojo y el violeta. "El rosa se produce cuando los lados rojo y violeta se juntan, pero no se juntan, lo que convierte al rosa en un acto de ilusión o, para decirlo sin rodeos, el rosa es un color inventado", escribe.

Quizá esta afirmación le confunda tanto como a mí (y sospecho que también a Krulwich). Krulwich cita como prueba un breve vídeo animado del equipo de Minute Physics. He incrustado el vídeo más abajo para que puedas verlo por ti mismo, pero la parte importante para nuestros propósitos es su explicación de dónde viene el rosa:

https://blogs.scientificamerican.com/observations/stop-this-absurd-war-on-the-color-pink/


lunes, 5 de febrero de 2024

AI Can Design Totally New Proteins From Scratch—It’s Time to Talk Biosecurity

 

AI Can Design Totally New Proteins From Scratch—It’s Time to Talk Biosecurity

Now, thanks to AI, custom proteins are a dime a dozen. Made-to-order proteins often have specific shapes or components that give them abilities new to nature. From longer-lasting drugs and protein-based vaccines, to greener biofuels and plastic-eating proteins, the field is rapidly becoming a transformative technology.

Custom protein design depends on deep learning techniques. With large language models—the AI behind OpenAI’s blockbuster ChatGPT—dreaming up millions of structures beyond human imagination, the library of bioactive designer proteins is set to rapidly expand.

“It’s hugely empowering,” Dr. Neil King at the University of Washington recently told Nature. “Things that were impossible a year and a half ago—now you just do it.”

Yet with great power comes great responsibility. As newly designed proteins increasingly gain traction for use in medicine and bioengineering, scientists are now wondering: What happens if these technologies are used for nefarious purposes?

A recent essay in Science highlights the need for biosecurity for designer proteins. Similar to ongoing conversations about AI safety, the authors say it’s time to consider biosecurity risks and policies so custom proteins don’t go rogue.

The essay is penned by two experts in the field. One, Dr. David Baker, the director of the Institute for Protein Design at the University of Washington, led the development of RoseTTAFold—an algorithm that cracked the half-decade problem of decoding protein structure from its amino acid sequences alone. The other, Dr. George Church at Harvard Medical School, is a pioneer in genetic engineering and synthetic biology.

They suggest synthetic proteins need barcodes embedded into each new protein’s genetic sequence. If any of the designer proteins becomes a threat—say, potentially triggering a dangerous outbreak—its barcode would make it easy to trace back to its origin.

The system basically provides “an audit trail,” the duo write.

Worlds Collide

Designer proteins are inextricably tied to AI. So are potential biosecurity policies.

Over a decade ago, Baker’s lab used software to design and build a protein dubbed Top7. Proteins are made of building blocks called amino acids, each of which is encoded inside our DNA. Like beads on a string, amino acids are then twirled and wrinkled into specific 3D shapes, which often further mesh into sophisticated architectures that support the protein’s function.

Top7 couldn’t “talk” to natural cell components—it didn’t have any biological effects. But even then, the team concluded that designing new proteins makes it possible to explore “the large regions of the protein universe not yet observed in nature.”

Enter AI. Multiple strategies recently took off to design new proteins at supersonic speeds compared to traditional lab work.

One is structure-based AI similar to image-generating tools like DALL-E. These AI systems are trained on noisy data and learn to remove the noise to find realistic protein structures. Called diffusion models, they gradually learn protein structures that are compatible with biology.

Another strategy relies on large language models. Like ChatGPT, the algorithms rapidly find connections between protein “words” and distill these connections into a sort of biological grammar. The protein strands these models generate are likely to fold into structures the body can decipher. One example is ProtGPT2, which can engineer active proteins with shapes that could lead to new properties.

Digital to Physical

These AI protein-design programs are raising alarm bells. Proteins are the building blocks of life—changes could dramatically alter how cells respond to drugs, viruses, or other pathogens.

Last year, governments around the world announced plans to oversee AI safety. The technology wasn’t positioned as a threat. Instead, the legislators cautiously fleshed out policies that ensure research follows privacy laws and bolsters the economy, public health, and national defense. Leading the charge, the European Union agreed on the AI Act to limit the technology in certain domains.

Synthetic proteins weren’t directly called out in the regulations. That’s great news for making designer proteins, which could be kneecapped by overly restrictive regulation, write Baker and Church. However, new AI legislation is in the works, with the United Nation’s advisory body on AI set to share guidelines on international regulation in the middle of this year.

Because the AI systems used to make designer proteins are highly specialized, they may still fly under regulatory radars—if the field unites in a global effort to self-regulate.

At the 2023 AI Safety Summit, which did discuss AI-enabled protein design, experts agreed documenting each new protein’s underlying DNA is key. Like their natural counterparts, designer proteins are also built from genetic code. Logging all synthetic DNA sequences in a database could make it easier to spot red flags for potentially harmful designs—for example, if a new protein has structures similar to known pathogenic ones.

Biosecurity doesn’t squash data sharing. Collaboration is critical for science, but the authors acknowledge it’s still necessary to protect trade secrets. And like in AI, some designer proteins may be potentially useful but too dangerous to share openly.

One way around this conundrum is to directly add safety measures to the process of synthesis itself. For example, the authors suggest adding a barcode—made of random DNA letters—to each new genetic sequence. To build the protein, a synthesis machine searches its DNA sequence, and only when it finds the code will it begin to build the protein.

In other words, the original designers of the protein can choose who to share the synthesis with—or whether to share it at all—while still being able to describe their results in publications.

A barcode strategy that ties making new proteins to a synthesis machine would also amp up security and deter bad actors, making it difficult to recreate potentially dangerous products.

“If a new biological threat emerges anywhere in the world, the associated DNA sequences could be traced to their origins,” the authors wrote.

It will be a tough road. Designer protein safety will depend on global support from scientists, research institutions, and governments, the authors write. However, there have been previous successes. Global groups have established safety and sharing guidelines in other controversial fields, such as stem cell research, genetic engineering, brain implants, and AI. Although not always followed—CRISPR babies are a notorious example—for the most part these international guidelines have helped move cutting-edge research forward in a safe and equitable manner.

To Baker and Church, open discussions about biosecurity will not slow the field. Rather, it can rally different sectors and engage public discussion so custom protein design can further thrive.

https://singularityhub.com/2024/01/29/ai-can-design-totally-new-proteins-from-scratch-its-time-to-talk-biosecurity/