Lambda Repressor. The repressor molecule of the Lambda bacteriophage binds not only to the OR1 site to prevent Cro transcription, but also to OR2, where it aids the binding of RNA polymerase to the repressor promoter. In fact a repressor dimer bound to OR1 interacts cooperatively with a second dimer binding to OR2.
Mandevillas grow as tropical perennials in frost-free regions. When looking for an attractive, blooming tropical vine, don't overlook mandevillas (Mandevilla spp.). These lovely climbing vines have abundant and showy blossoms that are produced for a period of several months.n these areas, mandevilla vines can reach a height of 10 to 20 feet, with older stems becoming woody and thick. In parts of zone 8 where winter frosts might occur, mandevillas planted outdoors often die back to the ground but regrow from surviving roots the next spring.
Perennial Sage. Hybrid perennial sage, a relative of the herb garden favorite, combines 18-inch spikes of blue, purple, or white perennial flowers with attractive gray-green foliage. Plant sage in the front or middle of the border in a sunny spot. The variety shown here, 'May Night', is both cold-hardy and showy.hese perennial flowers are valued in the garden for its ferny, gray-green or dark green, spicy-scented foliage and showy, flat-topped clusters of flowers in pink, red, white, or yellow appearing from late spring to early fall. 1  Learn more about yarrow.