Genetic code

• And even those without naturally curly hair might notice their hair curling – or, let’s be honest, frizzing – a bit on humid summer days.
• As a person with curly hair, I’m always looking for the best way to care for and understand my hair.
• As a chemist, I’m interested in the science behind how my hair behaves at the molecular level.

Hair structure

• Hair begins growing under the skin’s surface, but it’s what happens after it pokes through the skin that determines whether you have a good hair day or a bad one.
• Next is the cortex, which makes up most of a hair and is analogous to the wood of a tree.
• The exact shape of that bundle is determined by the hair follicle, which is a pore on the skin from where the hair grows.
• So a straight follicle produces straight hair and a curved follicle produces curly hair.

Hair in the summer

• So, heat and water can rearrange the proteins in your hair by breaking the hydrogen bonds that keep their structure together.
• In your hair, water can form hydrogen bonds between the rows of proteins in your hair’s cortex.
• Many people consider high humidity to be the problem behind frizzy hair, but styling your hair under high humidity and then entering a less humid environment can also be an issue.
• Water molecules leaving the hair’s cortex can also lead to a change in hair behavior.

Treating summer hair

• When the cuticle is healthy, it can protect the cortex, making your hair less susceptible to changes in the weather or environment.
• The bottom line is that a healthy hair cuticle helps keep proper moisture in the cortex.
• The good news is that by understanding your hair and treating it well, you can help prevent the undesired effects of humidity.

• The universality of the genetic code indicates a common ancestry among all living organisms and the essential role this code plays in the structure, function and regulation of biological cells.
• Understanding how the genetic code works is the foundation of genetic engineering and synthetic biology.
• Just as computers need strings of binary code to function, biological processes also rely on bits of information.

Different words for the same thing

• Ribosomes read three-letter words called codons, and there are 64 different possible combinations of the four letters that make different codons.
• In this list of 64 words, 61 encode amino acids, and three signal the ribosome to stop protein synthesis in the cell.
• In fact, since there are only 20 amino acids but 61 different words to encode them, there is quite a lot of overlap.

Engineering nature’s guidelines

• The mapping of the 61 codes onto the the 20 amino acids would be roughly equal, with each amino acid assigned three codons.
• Not only does the final form of a protein need to be optimal, but so do its intermediate forms.
• Scientists understand some of the guidelines that nature follows when engineering the genetic code.

Information theory and genetics

• Nature’s affinity for optimization using this irrational number is responsible for the infinitely repeating fractals seen in jagged shorelines, fern leaves, snowflakes and trees.
• Beyond biology, information optimization using e also has applications in mathematics and cosmology.
• Entropy is a measure of disorder in a system, and the maximum entropy principle states that systems evolve to states of greater disorder.
• Although there are many biological mysteries that scientists have yet to solve, information theory can be a powerful tool to help crack the genetic code.

• “Receiving Fast Track designation from the FDA reinforces Ambrx’s belief in ARX517 as a potential novel treatment for mCRPC and underscores the urgent need for improved treatment options for patients at this advanced stage of prostate cancer,” said Sandra Aung, Ph.D., Chief Clinical Officer of Ambrx.
• Daniel J. O'Connor, Chief Executive Officer of Ambrx added: "This Fast Track designation represents a significant milestone for Ambrx.
• Upon binding to PSMA on the surface of cancer cells, ARX517 is internalized and pAF-AS269, its cancer cell killing payload, is released following lysosomal metabolism.
• ARX517 has the potential to be a first- and best-in-class anti-PSMA ADC addressing the high unmet medical need in mCRPC.

• Unlike sparrows, finches and most other birds, hummingbirds can taste sweetness because they carry the genetic instructions necessary to detect sugar molecules.
• Like hummingbirds, we humans can sense sugar because our DNA contains gene sequences coding for the molecular detectors that allow us to detect sweetness.
• Neuroscientists like me are working to decipher how this intricate interplay between genes and diet shapes taste.

The role of genes in sensing taste

• The interactions between taste receptors and food molecules give rise to the five basic taste qualities: sweetness, savoriness, bitterness, saltiness and sourness, which are transmitted from the mouth to the brain via specific nerves.
• While the presence of genes encoding for functional taste receptors in our DNA allows us to detect food molecules, how we respond to these also depends on the unique combination of taste genes we carry.
• Like ice cream, genes, including those for taste receptors, come in different flavors.
• What is certain is that while genetics lays the groundwork for taste sensations and preferences, experiences with food can profoundly reshape them.

How diet influences taste

• Some molecules from the mother’s diet, like garlic or carrots, reach the fetus’s developing taste buds via the amniotic fluid and can affect the appreciation of these foods after birth.
• Although we researchers are still working out the exact how and why, studies show that high sugar and fat intake in animal models dampens the responsiveness of taste cells and nerves to sugars, modifies the number of taste cells available and even flips genetic switches in the taste cells’ DNA.
• In my lab, we’ve shown that these taste alterations in rats return to normal within weeks when the extra sugar is removed from the diet.

Illness can also influence taste

• Researchers have found that about 40% of people infected with SARS-CoV-2 experience impairment in taste and smell.
• Although researchers don’t understand what causes these sensory alterations, the leading hypothesis is that the virus infects the cells that support the taste and smell receptors.

Training taste buds for healthier eating

• By shaping our eating habits, the intricate dance between genes, diet, disease and taste can affect the risk for chronic diseases.
• Beyond distinguishing food from toxins, the brain uses taste signals as a proxy to estimate the filling power of foods.
• Since diet shapes our senses, we can actually train our taste buds – and our brains – to respond and prefer foods with lower quantities of sugar and salt.
• Reformulating foods tailored to our genes and the plasticity of our taste buds could be a practical and powerful tool to enhance nutrition, promote health and decrease the burden of chronic disease.