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BITTER RECEPTORS. “Bitter taste is mediated by the taste 2 receptor (TAS2R) gene family, a branch of Family A GPCRs. The human genome has 25 TAS2R subtypes and over a thousand of bitter compounds are currently known, with numerous additional bitter tastants predicted.” https://www.nature.com/articles/s42003-021-01964-y View in LinkedIn

UMAMI. “A combination of TAS1R3 with another member of the TAS1R family, TAS1R1, results in a dimer that mediates umami taste, elicited by molecules such as glutamate or, in case of the rodent umami receptor, other L-amino acids.” https://www.nature.com/articles/s42003-021-01964-y View in LinkedIn

SWEETENERS. “Interestingly, not all artificial sweeteners are recognized by rodents. Differences in human and rodent responses to tastants, as well as sweetness inhibitors such as lactisole, have been useful for delineating the molecular recognition of sweet compounds—using human-mouse chimeric receptors, it was shown that the transmembrane domain (TMD) of human TAS1R3 is required for the activating effects of cyclamate29 and for the inhibitory effect of lactisole.” https://www.nature.com/articles/s42003-021-01964-y View in LinkedIn

CIRCADIAN EFFECT. “Probably the best-established effect of D2O is the increase of the circadian oscillation length upon its administration to both animals and plants. This has been attributed to a general slowdown of metabolism upon deuteration, although the exact mechanism of this effect is unknown.” https://www.nature.com/articles/s42003-021-01964-y View in LinkedIn

TOXICOLOGY. “Small levels of deuteration are, nevertheless, harmless. This is understandable given the fact that about 1 in every 6400 hydrogens in nature is found in its stable isotope form of deuterium. Oral doses of several milliliters of D2O are safe for humans and are used in the isotopic form D218O for metabolic measurements in clinical praxis (known as “doubly labeled water” technique).” https://www.nature.com/articles/s42003-021-01964-y View in LinkedIn

“BIOLOGICAL EFFECTS are observable for high doses of D2O. While bacteria or yeasts can function in practically pure D2O, albeit with somewhat hindered growth rate, for higher organisms damaging effects on cell division and general metabolism occur at around 25% deuteration, with lethal conditions for plants and animals typically occurring at ~40–50% deuteration of the body water.” https://www.nature.com/articles/s42003-021-01964-y View in LinkedIn

D2O. “In comparison, a mere dissolution of atmospheric CO2 and subsequent formation of dilute carbonic acid in open containers has a significantly stronger influence on the pH of water, changing it by more than one unit.” https://www.nature.com/articles/s42003-021-01964-y View in LinkedIn

PHYSICAL PROPERTIES. “A more subtle effect of deuteration is the formation of slightly stronger hydrogen (or deuterium) bonds in D2O as compared to H2O3. This results in a small increase of the freezing and boiling points by 3.8 °C and 1.4 °C, respectively, and in a slight increase of 0.44 in pH (or pD) of pure water upon deuteration.” https://www.nature.com/articles/s42003-021-01964-y View in LinkedIn

HEAVY WATER. “The most notable difference in physical properties between D2O and H2O is the roughly 10% higher density of the former liquid, which is mostly a trivial consequence of deuterium being about twice as heavy as hydrogen.” https://www.nature.com/articles/s42003-021-01964-y View in LinkedIn