S. Dutta Gupta

Bio: S. Dutta Gupta is an academic researcher from University of Calcutta. The author has contributed to research in topics: Ascorbic acid & Semicarbazone. The author has an hindex of 3, co-authored 3 publications receiving 64 citations.

Evolution and the biosynthesis of ascorbic acid

Abstract: The ability to synthesize ascorbic acid is absent in the insects, invertebrates, and fishes. The biosynthetic capacity started in the kidney of amphibians, resided in the kidney of reptiles, became transferred to the liver of mammals, and finally disappeared from the guinea pig, the flying mammals, monkey, and man. A similar transition in the biosynthetic ability was observed in the branched evolution of the birds.

Synthesis and some major functions of vitamin C in animals.

Abstract: The requirement of ascorbic acid (vitamin C ) is a common property of living organisms, and it has long been considered that all animals except the guinea pig, monkey, and man can synthesize this vitamin. The classic method for determining the ability of an animal to synthesize ascorbic acid is to feed it a scorbutogenic diet for a prolonged period and to observe the appearance of the scurvy syndrome. Obviously, the method is laborious and time-consuming. Also, the onset of the scorbutic syndrome depends on the ascorbic-acid-retention capacity of the animal. For example, whereas the guinea pigs can be made scorbutic in about 3 weeks, it takes 3 to 4 months to produce scurvy in man. Since the discovery of the technique for studying ascorbic acid synthesir in vitro,1-8 the task has become much simpler. In this technique, the tissue homogenates or the subcellular fractions are incubated with precursors of ascorbic acid and the amount of the vitamin formed is estimated. Using the in vitro method, we have examined the ascorbic acid synthesizing abilities of different species of animals in the phylogenetic tree, and the results are given below.

The genetics of vitamin C loss in vertebrates.

Abstract: Vitamin C (ascorbic acid) plays important roles as an anti-oxidant and in collagen synthesis. These important roles, and the relatively large amounts of vitamin C required daily, likely explain why most vertebrate species are able to synthesize this compound. Surprisingly, many species, such as teleost fishes, anthropoid primates, guinea pigs, as well as some bat and Passeriformes bird species, have lost the capacity to synthesize it. Here, we review the genetic bases behind the repeated losses in the ability to synthesize vitamin C as well as their implications. In all cases so far studied, the inability to synthesize vitamin C is due to mutations in the L-gulono-γ-lactone oxidase (GLO) gene which codes for the enzyme responsible for catalyzing the last step of vitamin C biosynthesis. The bias for mutations in this particular gene is likely due to the fact that losing it only affects vitamin C production. Whereas the GLO gene mutations in fish, anthropoid primates and guinea pigs are irreversible, some of the GLO pseudogenes found in bat species have been shown to be reactivated during evolution. The same phenomenon is thought to have occurred in some Passeriformes bird species. Interestingly, these GLO gene losses and reactivations are unrelated to the diet of the species involved. This suggests that losing the ability to make vitamin C is a neutral trait.