Biological survival curiosities

From CSWiki

See also the Museum of unintended consequences.

[edit] Adding oregno to corn

From Science.

Many plants emit signals to augment their defenses against attack by insects; some of these signals are known to work by attracting predators of the attackers. Maize roots under threat from larvae of the western corn rootworm normally emit the terpene caryophyllene, which serves to mobilize nematodes that then kill these larvae. However, most cultivated maize has lost the capacity to produce this terpene.

Degenhardt et al. have engineered transgenic maize plants that carry a caryophyllene synthase gene from oregano. This manipulation restored the production of this compound, with the consequence that nematodes reduced the number of rootworms by more than half, resulting in much less root damage. This finding confirms that nematodes can be recruited effectively by caryophyllene and provides the basis for a pest biocontrol strategy to improve cultivated plants.

[edit] Upward growing root systems

From Science.

Land plants have evolved a variety of specialized adaptations to gather nutrients from unlikely substrates, such as Amazonian trees whose roots grow upward on the bark of neighboring trees. The latest discovery—the snow roots of an alpine plant—comes from 2800 m in the Caucasus Mountains. Onipchenko et al. found that the herbaceous plant Corydalis conorhiza (a member of the poppy family) produces extensive networks of roots that grow upward and laterally into the snowpack that carpets the high slopes until the July thaw. Isotope experiments showed that these roots, which are anatomically distinct from the normal roots that grow downward into the soil, take up nitrogen directly from the snow-pack, thus exploiting a resource that would otherwise disappear down the mountainside during the brief summer.

[edit] Assembling Gradient Sensors

From Science

Bacteria cluster thousands of transmembrane chemoreceptors at opposite ends of the cell, allowing them to detect and follow food molecule gradients. Might the formation and maintenance of such clusters occur via stochastic assembly? To test this idea, Greenfield et al. used photoactivated localization microscopy (PALM) to count single fluorophore-tagged receptors with an optical resolution of 15 nm. They analyzed 1 million receptors and observed that many were present as singletons or small clusters in lateral regions of the cell (shown at left). A mathematical model in which the receptors are inserted randomly into the membrane, but can then be captured and incorporated into existing clusters, accounted for the observed distribution and predicted that the density of new clusters would be highest at a point farthest from a large cluster. Hence, through stochastic assembly, a cell with a large cluster at one pole will form a new large cluster at the opposite pole. Receptor clusters of appropriate size and stability thereby assemble without any specific cellular machinery to position the receptors.