Organ Transplantation from Pigs to Humans Could Be Possible, Thanks to Gene Editing

Author: Attabey Rodríguez Benítez

Editors: Sarah Kearns, Jimmy Brancho, and Whit Froehlich

Can you imagine a future where humans could receive organs from animals instead of having to wait for a donor? Well, this could be possible thanks to evidence from an international collaboration between labs in Harvard and China which resulted in a publication in the prestigious journal Science.

Continue reading “Organ Transplantation from Pigs to Humans Could Be Possible, Thanks to Gene Editing”

Semen’s Lesser-known Roles in Reproduction

Author: Brooke Wolford

Editors: Andrew McAllister, Molly Kozminsky, and Whit Froehlich

tinder_sperm
Image by Sierra Nishizaki

If you’re a millennial who thinks dating in the age of Tinder is difficult, you may find parallels between your dating life and the complexities of reproduction. The process of a sperm meeting an egg to create a cell that successfully implants in the uterine wall and subsequently creates a human is incredibly intricate. Similar to the world of dating, two have to meet, decide they like each other, and then invest time and energy to grow together as a couple. From finding a mate to the biological processes behind pregnancy, reproduction may seem downright impossible. Luckily mother nature has devised sneaky and fascinating ways to improve the chances of a successful pregnancy. Evolution favors those who pass their DNA on to as many offspring as possible, and natural selection has worked for years to optimize reproduction. If only Tinder were that good at getting you a date!

Continue reading “Semen’s Lesser-known Roles in Reproduction”

The Humble Phosphate Ion: Making Life “Go”

Author: John Charpentier

Editors; Noah Steinfeld, Tricia Garay, and Scott Barolo

A glance into any organic chemistry or biochemistry textbook reveals a dizzying variety of chemical compounds, reactions and mechanisms. It is not at all obvious why one particular class of reaction, the attachment and detachment of a phosphate group (PO43-) to molecules like nucleotides and proteins, is central to making the chemistry of life “go.”

Proteins: Not Just for Getting Swole, Brah

Fig1
Figure 1. A phosphate ion. Note the negative charges.

Proteins are the working-class heroes of the cell: they get things done. A protein’s function is largely determined by its shape, which in turn is dictated by the linear sequence of chemically distinct amino acid subunits it is composed of. The rules of protein folding are astonishingly complex. Generally speaking, the reluctance of hydrophobic (“water-fearing”) amino acids to project outward into the watery cytoplasm is the primary determinant of protein shape, but electrostatic interactions between amino acid residues are also important. Phosphate groups have three negative charges, which means that when they are linked to or removed from a protein by specialized enzymes, they can dramatically modify its shape and stability, and therefore its function. The phosphorylation/dephosphorylation cycle operates like a switch to regulate protein behavior: add a phosphate and you get a violent Mr. Hyde protein; take it off and you get the amiable Dr. Jekyll.

 

Fig2
Figure 2. Cellular homunculi don’t exist – decisions are made by integrating signaling inputs from the environment to effect changes in gene expression.

So where do we find phosphorylation in biochemistry? The answer is: pretty much everywhere! I will discuss two key examples. Firstly, phosphorylation is important in “cell signaling,” the sensing of messages from outside a cell and their incorporation into cellular decision-making. It’s worth observing that there isn’t anything we’d recognize as a brain in cells – decision-making is an emergent property of the integration of these signals, not the doing of a microscopic cellular homunculus pulling levers or “thinking.”

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Analyzing without Lysing: Non-Damaging Techniques for Monitoring Cells

Author: Sarah Kearns

Editors: Whit Froehlich, Ada Hagan, and Irene Park

The interior of a cell is inherently complex with a myriad of processes going on all at once. Despite the clean images that are commonly shown in diagrams and textbooks, the parts inside are more of a whirlwind of structural components, proteins, and products (see Figure 1).

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Figure 1. Left is a cartoon image of a whole cell highlighting the different organelles (cellular compartments). Right is a computer simulation of the cytoplasm, the fluid between organelles. There are thousands of chemical processes going on within it.

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Computing Levinthal’s Paradox: Protein Folding, Part 2

Author: Sarah Kearns

Editors: David Mertz, Zuleirys Santana Rodriguez, and Scott Barolo

In a previous post, we discussed how proteins fold into unique shapes that allow them to perform their biological functions. Through many physical and chemical properties, like hydrogen bonding and hydrophobicity, proteins are able to fold correctly. However, proteins can fold improperly, and sometimes these malformed peptides aggregate, leading to diseases like Alzheimer’s.

How can we figure out when the folding process goes wrong? Can we use computers to figure out the folding/misfolding process and develop methods to prevent or undo the damage done by protein aggregates?

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How to Fold (and Misfold) a Protein (Part 1)

Author: Sarah Kearns

Editors: David Mertz, Zulierys Santana-Rodriguez, and Scott Barolo

Proteins do most of the work in your body: Depending on their shape, they can digest your food, fire your neurons, give color to your eyes and allow you to see colors. Proteins follow instructions encoded in your DNA to fold into their shape, but how do they “know” what shape to fold into to perform their biological functions? What happens when they fold incorrectly?

Continue reading “How to Fold (and Misfold) a Protein (Part 1)”