A triad of somatic mutagenesis converges in self-reactive B cells to cause a virus-induced autoimmune disease.

The unexplained association between infection and autoimmune disease is strongest for hepatitis C virus-induced cryoglobulinemic vasculitis (HCV-cryovas). To analyze its origins, we traced the evolution of pathogenic rheumatoid factor (RF) autoantibodies in four HCV-cryovas patients by deep single-cell multi-omic analysis, revealing three sources of B cell somatic mutation converged to drive the accumulation of a large disease-causing clone. A method for quantifying low-affinity binding revealed recurring antibody variable domain combinations created by V(D)J recombination that bound self-immunoglobulin G (IgG) but not viral E2 antigen.

Filtering out the noise: metagenomic classifiers optimize ancient DNA mapping.

Contamination with exogenous DNA presents a significant challenge in ancient DNA (aDNA) studies of single organisms. Failure to address contamination from microbes, reagents, and present-day sources can impact the interpretation of results. Although field and laboratory protocols exist to limit contamination, there is still a need to accurately distinguish between endogenous and exogenous data computationally.

Developmentally-regulated proteolysis by MdfA and ClpCP mediates metabolic differentiation during sporulation.

sporulation entails a dramatic transformation of the two cells required to assemble a dormant spore, with the larger mother cell engulfing the smaller forespore to produce the cell-within-a-cell structure that is a hallmark of endospore formation. Sporulation also entails metabolic differentiation, whereby key metabolic enzymes are depleted from the forespore but maintained in the mother cell. This reduces the metabolic potential of the forespore, which becomes dependent on mother-cell metabolism and the SpoIIQ-SpoIIIA channel to obtain metabolic building blocks necessary for development.

Bacterial diversity of cantaloupes and soil from Arizona and California commercial fields at the point of harvest.

Across the United States, melons are a high demand crop reaching a net production of 2.7 million tons in 2020 with an economic value of $915 million dollars. The goal of this study was to characterize the bacterial diversity of cantaloupe rinds and soil from commercial melon fields at the point of harvest from two major production regions, Arizona, and California.