In a study appearing online this week in the Proceedings of the National Academy of Sciences, researchers from the US and Germany describe the differential RNA sequencing approach they used to assess quorum sensing in the pathogenic bacterial species Vibrio cholerae. By sequencing and comparing transcripts in a wild type V. cholerae strain and a mutant strain that only grows to low density, the team identified a small regulatory RNA called VqmR that reins in the expression of genes involved in biofilm formation. The analysis also offered a more refined look at transcriptional and translational start sites in V. cholerae, identifying more than 100 small RNAs suspected of regulatory roles in the bug.
Austrian researchers characterized crossovers in individual sperm cells to look at the relationship between recombination hotspots, mutation frequency, and biased gene conversion events for another PNAS study. The team did allele-specific PCR and DNA sequencing on nearly 5,800 crossover sites in individual sperm cells from half a dozen donor men, targeting two known recombination hotspots. When they compared these sites to non-recombinant DNA sequences from the same individuals, the study's authors saw a higher rate of new mutations in the crossover regions, along with an apparent bias in gene conversion, which led to more frequent transmission of guanine and cytosine alleles rather than adenine and thymine bases.
Finally, researchers from the Rosalind Franklin University of Medicine and Science report on potential Parkinson's disease biomarkers uncovered through a network-based meta-analysis of four past microarray studies. Among differentially expressed genes in the Parkinson's cases and controls, the team narrowed in on two genes: HNF4A, which showed enhanced expression in patients, and PTBP1, a gene showing diminished expression in those with the disease. These patterns were validated through quantitative PCR testing on dozens more cases and controls, the study authors report, noting that levels of the proposed biomarkers shifted over time in concert with Parkinson's disease development. GenomeWeb has more on the study, here.