A dose-rate effect in single-particle electron microscopy.

A low beam intensity, low electron dose imaging method has been developed for single-particle electron cryo-microscopy (cryo-EM). Experiments indicate that the new technique can reduce beam-induced specimen movement and secondary radiolytic effects, such as "bubbling". The improvement in image quality, especially for multiple-exposure data collection, will help single-particle cryo-EM to reach higher resolution.

Aging: the sins of the parents.

Yeast cells have an asymmetric, stem-cell-like division. As the mother cell ages it becomes 100 times more genetically unstable, but it is only the daughter cells that exhibit loss of heterozygosity; the latter effect is not connected to SIR2-dependent aging, but seems to be accompanied by a loss of the DNA damage checkpoint.

Visualization of the domain structure of an L-type Ca2+ channel using electron cryo-microscopy.

The three-dimensional structure of the skeletal muscle voltage-gated L-type calcium channel (Ca(v)1.1; dihydropyridine receptor, DHPR) was determined using electron cryo-microscopy and single-particle averaging. The structure shows a single channel complex with an approximate total molecular mass of 550 kDa, corresponding to the five known subunits of the DHPR, and bound detergent and lipid.

Meiosis: Avoiding inappropriate relationships.

Meiosis is distinguished from mitosis by the way double-strand breaks are made and by the synapsis and segregation of homologous chromosomes. Recent studies with the yeast Saccharomyces cerevisiae have identified some of the key players that link homologous recombination to synaptonemal complex formation.