A California team has garnered evidence implicating the research organism Xenopus laevis (the South African clawed frog) in the presence of the frog fungal pathogen Batrachochytrium dendrobatis in California. As they reported in PLOS One, investigators surveyed more than 200 archived frog samples by real-time PCR, including 178 samples collected in Africa between 1871 and 2000 and almost two dozen more collected in California between 2001 and 2010. The group found DNA from the Bd fungus in eight samples overall, with the earliest appearing in a 1934 sample from Kenya. Three of 23 California samples also carried the fungus. "If wild Xenopus appeared in California decades ago, during the 1970s … then by strong inference and supported by the findings reported here," they write, "introduction of Bd into this geographical area could have occurred in part via Bd infected Xenopus laevis."
Mycoplasma pneumoniae may turn up in the upper respiratory tracts children who aren't suffering from respiratory tract infections, according to a study in PLOS Medicine. Researchers from Erasmus MC and elsewhere used real-time PCR to test upper respiratory tract samples from 321 children with infections and 405 children without. Some 21 percent of asymptomatic children tested positive for M. pneumoniae DNA, compared to around 16 percent of those with documented infections, suggesting that the presence of M. pneumoniae alone may not necessarily herald infection. In follow-up experiments involving 202 more children, around 56 percent carried DNA from other bacterial or viral pathogens, too, both in the respiratory tract infection and asymptomatic groups.
The University of Würzburg's Cynthia Sharma and colleagues undertook a transcriptomics-based analysis of the gastroenteritis-causing bacterial species Campylobacter jejuni — work they describe in PLOS Genetics. The team used its so-called differential RNA sequencing strategy to sequence and compare the transcriptomes of four C. jejuni isolates (three from humans and one from a chicken), applying a new method to automatically annotate transcription start sites in each. "Overall," they write, "our study provides new insights into strain-specific transcriptome organization and [small RNAs], and reveals genes that could modulate phenotypic variation among strains despite high conservation at the DNA level."