BioVoice News eMag September 2023 | Page 75

Biologists have hypothesized that apiin offers antioxidant , anti-UV light , and insect repellent effects , thus serving essential biological and ecological roles .
producing apiin in bacterial organisms such as Escherichia coli .”
One of the most crucial things that made this study possible was a method that the researchers had previously developed to produce a critical molecule in apiin synthesis : UDP- Apiose . The role of the ApiT enzyme is to transfer the apiose residue in UDP-Apiose and ‘ attach it ’ to the incomplete apiin molecule in the final modification step . However , this compound was not commercially available , so the researchers came up with a way to isolate and stabilize it using bulky positive ions .
First , the team conducted genetic screening analyses on celery to find potential ApiT-encoding genes . They narrowed the initial search to genes specific to the family of enzymes to which ApiT belongs , identifying 26 potential candidate genes . Of these , the mRNA expression of one of these candidates , UGT94AX1 , was found to be particularly high in celery leaves , which is the primary site of apiin production . Based on the physiochemical characteristics of this candidate gene , the researchers were confident they were on the right track .
To prove that UGT94AX1 was indeed the ApiT gene , they investigated its

Biologists have hypothesized that apiin offers antioxidant , anti-UV light , and insect repellent effects , thus serving essential biological and ecological roles .

expression profile over the course of leaf development . They found that the levels of apiin and UGT94AX1 expression roughly coincided . Afterwards , the researchers used genetically modified bacterial cultures that expressed UGT94AX1 with a special chemical tag to make it easily soluble . They incubated the purified protein encoded by UGT94AX1 with UDP-Apiose and the final precursor to apiin and found that this mixture produced apiin in the expected amounts . This new approach for detecting apiosyltransferase activity cleared all doubts that the candidate gene UGT94AX1 was indeed ApiT .
Way forward
Worth noting , having access to apiin in high amounts will help us not only understand its natural role , but also identify its health benefits and medical applications . In this regard , Prof . Ishimizu comments : “ If the function of apiin is clarified , it could lead to the development of mild insect repellents in agriculture , tranquilizers with fewer side effects , and anxiolytic soft drinks .”
It seems there is much to gain from understanding apiin better , so let us hope further studies on this compound are fruitful !

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