All life is cellular, but the origins of cellularity remain unknown. Scientists have discovered that simple organic compounds like glycolic and lactic acid polymerize and self-assemble into cell-sized droplets when dried and rewetted, as might have happened along primitive beaches and drying puddles. These cell-like compartments can trap and concentrate biomolecules, and can merge and separate, forming versatile and heterogeneous cell-like containers possibly critical for the origin of life.
New DNA analysis has revealed surprising genetic diversity in a bacterium that poses a persistent threat to the algae biofuels industry. With the evocative name Vampirovibrio chlorellavorus, the predatory pest sucks out the contents of the algae cells (thus the vampire reference) and reduces a productive, thriving, green algae pond to a vat of rotting sludge.
A team of scientists has discovered that the toxin SidJ in Legionella bacteria enforces a unique modification on human proteins and helps legionella grow inside human cells. SidJ hijacks human protein Calmodulin to its own advantage in one of the classic examples of pathogenic bacteria exploiting the human molecular machinery and turning it against us. This makes SidJ an ideal target to curb Legionella infection.
Cells assemble dynamically: their components are continuously exchanging and being replaced. This enables the structures to adapt easily to different situations, and by rearranging the components to respond to stimuli faster, to renew or to form just on demand. The microtubules, a scaffold structure made of protein fibers that can be found in the cytoplasm of the cells of algae, plants, fungi, animals and humans, are one such dynamic mesh. Because of their self-organizing structure, these fibers constantly form and degrade at the same time, thereby actively supporting the cell in complex tasks such as cell division or locomotion. The fibers require energy to form and maintain such dynamic states. Now, for the first time, scientists have succeeded in programming the dynamics of such dissipative, i.e. energy-consuming, structures in an artificial chemical system on the basis of DNA components.
The enzyme ribonucleotide reductase is a bottleneck for cancer cell growth. Scientists have identified a way of targeting ribonucleotide reductase that may avoid the toxicity of previous approaches, informing focused drug discovery efforts.
Almost all living organisms have gate-like protein complexes in their cell membranes that get rid of unwanted or life-threatening molecules. These ABC transporters are also responsible for resistance to antibiotics or chemotherapy. Researchers have now succeeded in decrypting all the stages of the transport mechanism.
More than half of our genome consists of transposons, DNA sequences that are reminiscent of ancient, extinct viruses. Transposons are normally silenced by a process known as DNA methylation, but their activation can lead to serious diseases. Very little is known about transposons but researchers in an international collaboration project have now succeeded for the first time in studying what happens when DNA methylation is lost in human cells. These findings provide new insight into how changes in DNA methylation contribute to diseases.