Dans Genome Web
In this week's Science, a group of European scientists reveals the heretofore unknown steps in the process by which the Madagascar periwinkle produces vinblastine, a potent anticancer agent that the flowering plant makes in small quantities. While most of the 31 enzymatic reactions involved in vinblastine production were known, two remained a mystery. By screening RNA data, the researchers identify two enzymes — dubbed tabersonine synthase (TS) and catharanthine synthase (CS) — as the missing links in the process. When they inhibit the genes that encode these enzymes in Madagascar periwinkles, the plants do not produce vinblastine. Additional analysis uncovered the other enzymes that work with TS and CS in the vinblastine-production process.
Dans New Straits Times
The C. roseus, known by its common name of Old Maid, is a woody herb from the dogbane family, Apocynaceae. This plant is also known as Madagascar periwinkle as it originates from there. Being a desert plant, it can withstand heat and drought well. The plant’s glossy dark green leaves are oval to oblong in shape. The flowers have five petals, are delicate-looking and are white to dark pink, with darker red centres. This upright plant can grow to about 90cm high. In addition to those wild types, hybrid synthetic varieties or cultivars (C. roseus x hybrida) bred in recent times have expanded the colour range of the blooms, improved bloom size, increased flowers, prolonged the blooming period and have superior heat tolerance. Madagascar periwinkles don’t only come in white and pinks but also in red, dark pink, blue and orange shades. Their growth habits can be either weeping or upright. Performing best in full sun locations, they’re usually between 30 and 60cm high and grow into a rounded form. Medium textured, these plants can be cultivated in pots as edgings or as ground cover.
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