In this week’s Science, researchers at Caltech and MIT report their use of microfluidic digital PCR "to physically link single bacterial cells harvested from a natural environment with a viral marker gene." The authors suggest that their approach — which "does not require culturing hosts or viruses" — is a useful "method for examining virus-bacterium interactions in many environments."
The Washington University School of Medicine's Jeffrey Gordon and his colleagues present a statistical model to predict more than 60 percent of the variation in species abundance in response to randomized perturbations in a model community of 10 sequenced human gut bacteria introduced into gnotobiotic mice. "We were able to identify which factors in the diet best explained changes seen for each community member," Gordon et al. write in this week's Science, adding that their "approach is generally applicable, as shown by a follow-up study involving diets containing various mixtures of pureed human baby foods."
A team led by researchers at Harvard Medical School reports that, in Xenopus egg extracts, a broken sister chromatid that has resulted from a double-strand break is "repaired via RAD51-dependent strand invasion into the regenerated sister." The Harvard-led team’s study shows how a double-strand break is completely repaired via homologous recombination in vitro.
In a paper published online in advance in Science this week, an international team led by investigators at the Johns Hopkins Medical Institutions reports that 61 percent of the pancreatic neuroendocrine tumors they examined show abnormal telomeres "characteristic of a telomerase-independent telomere maintenance mechanism termed ALT," or alternative lengthening of telomeres. The team also shows that the tumors that displayed abnormal telomeres had ATRX or DAXX mutations. "These data suggest that an alternative telomere maintenance function may operate in human tumors with alterations in the ATRX or DAXX genes," the authors write.