The Public Library of Science is an ongoing effort toward open-access science -- that is, not forcing you to have a subscription to read new articles and, ideally, letting a reasonably interested layperson understand why the work in question is important. To this end, PLoS has a number of peer-reviewed journals that feature significant, cutting-edge research with the bonus of an added explanation for the general reader, written by a science writer. In other words, the kind of thing you'd read in Popular Science magazine.
As part personal exercise and part encouragement to others to at least read the summaries, I'm going to start putting up some brief comments on the articles that excited me from the PLoS Journals. That I'll do in the extended.
Brachman and Parniske provide an overview of the symbiosis between plant roots and Glomeromycota fungi. This relationship, in which root-local fungi help plants extract nutrients from soil, may be present in 80% of plants and use up to 20% of the output of worldwide photosynthesis. The interaction is old, and colonization of land by plants may have depended on the fungal partner's ability to extract nutrients.
In the lab, these relationships are "promiscuous", which is odd given the long period of presumptive coevolution. Both plants and fungi release diffusible signaling molecules that induce changes in the partner organism. Strigolactones were recently identified as one signaling molecule from plants to fungus and, despite the great age of this class of fungi, they are surprisingly effective across the many kinds of Glomeromycota -- this suggests that strigolactones were the signaling molecules used by the first land plants with their first fungal partners.
Data sharing is a big issue in modern biology -- the more access everyone has, the less likely are duplicated efforts and the more information you have to generate hypotheses and ideas. In this correspondence, Noor, Zimmerman and Teeter take a look at how often researchers fail to submit DNA data to a very well-established biological database -- GenBank. As they point out, despite many publications theoretically requiring submission of sequences to GenBank for publication, not everyone complies with this rule. They surveyed half a year's worth of material from six journals with explicit "you must submit sequences to GenBank" policy and found:
No journal had complete compliance with its requirement for all DNA sequences to have been submitted to GenBank (Table 1). Between 3% and 20% of papers in these journals did not include GenBank accession numbers, and between 3% and 15% of studies never submitted their DNA sequences at all. We also identified several papers with errors in the supplied accession numbers, but these errors were not counted. Table 1 also notes “special cases” that we considered less egregious violations of the journal rules. In these cases, the DNA sequences were noted in the paper itself, either as supplementary materials or by noting identity to published sequences.
They propose a "sanction" for authors who have failed to submit sequence information of removing the online version of their article until such time as they do submit the sequence information.
PCR is a wonderful technique, allowing detection of as little as one molecule of target DNA. However, it is kept out of widespread use by its need for a thermocycler -- a device that can ramp temperatures up and down over a wide range every couple of minutes to remove DNA primers from their targets, then allow binding again, then synthesis, then repeat the whole process. Functionally, this means you can't just do PCR in a field kit -- you need something about the size of a laptop, but much heavier and much more power dependent.
Piepenburg et al have developed a method to amplify DNA at room temperature, through the clever addition of recombinase -- an enzyme of the type viruses sometimes use to insert themselves into DNA. Recombinases have evolved to ably open up DNA at "normal" temperatures. As described well in the general summary, this method is sensitive enough to identify as little as one or two copies of DNA from a drug-resistant bacterium, distinguishing between it and its drug-sensitive fellows, yet robust enough to be used on a common "dipstick" style test that could be applied in the clinic, or perhaps in the field. The upshot is faster, more convenient testing for your microbe of interest -- and that's a big deal.
Sigman and Dehaene studied just how the brain prioritizes parallel tasks -- that is, when two tasks are given near-simultaneously. The older "passive bottleneck" model says that tasks are processed in the order they arrive, then mechanical action is carried out. However, this paper's results suggest that near-simultaneous tasks are loaded into the brain, then a decision is made about what order to carry them out. Note that this whole paper is about near-simultaneous things -- the test is doing a greater-than/less-than calculation while discerning a tone -- an effectively simultaneous task. You can read the the synopsis .