In the absence of lactose, the repressor protein encoded by the I gene binds to the lac operator and prevents transcription. Binding of allolactose to the repressor causes it to leave the operator. This enables RNA polymerase to transcribe the three genes of the operon.
A tough-skinned tropical fruit, the mango features a sweet, orange- to red-color flesh inside when ripe. Kensington pride, Kent, Palmer and sensation are only a few of the many varieties of mango available through groceries and markets.
Ripe Kesar mangoes from India, some of the best fruit in the world, are currently in season. Photographer: Evan Ortiz/Bloomberg. And good news: They're in. It's just the start of the season; about 100,000 tonnes of Indian mangoes will travel to the U.S. before the season ends in June. That's almost twice what we got last year, when early rains ruined massive amounts of India's crop (and prices almost doubled).