Molecular Biology and Physiology
Research Article | Molecular Biology and PhysiologyExpression and Immunostaining Analyses Suggest that Pneumocystis Primary Homothallism Involves Trophic Cells Displaying Both Plus and Minus Pheromone ReceptorsThe fungi belonging to the genus Pneumocystis may cause severe pneumonia in immunocompromised humans, a disease that can be fatal if not treated. This disease is nowadays one of the most frequent invasive fungal infections worldwide. Whole-genome sequencing revealed that the sexuality of these fungi involves a single partner that can self-fertilize. Here, we report that two receptors recognizing specifically excreted pheromones...
Research Article | Molecular Biology and PhysiologyBactericidal Disruption of Magnesium Metallostasis in Mycobacterium tuberculosis Is Counteracted by Mutations in the Metal Ion Transporter CorAAntimycobacterial agents might shorten the course of treatment by reducing the number of phenotypically tolerant bacteria if they could kill M. tuberculosis in diverse metabolic states. Here we report two chemically disparate classes of agents that kill M. tuberculosis both when it is replicating...
Research Article | Molecular Biology and PhysiologyA Vibrio cholerae BolA-Like Protein Is Required for Proper Cell Shape and Cell Envelope IntegrityBolA-like proteins are conserved across prokaryotes and eukaryotes. These proteins have been linked to a variety of phenotypes, but the pathways and mechanisms through which they act have not been extensively characterized. Here, we unraveled the role of the BolA-like protein IbaG in the cholera pathogen Vibrio cholerae. The absence of IbaG was associated with...
Editor's Pick Research Article | Molecular Biology and PhysiologyUbiquinone Biosynthesis over the Entire O2 Range: Characterization of a Conserved O2-Independent PathwayIn order to colonize environments with large O2 gradients or fluctuating O2 levels, bacteria have developed metabolic responses that remain incompletely understood. Such adaptations have been recently linked to antibiotic resistance, virulence, and the capacity to develop in complex ecosystems like the microbiota. Here, we identify a novel pathway for the biosynthesis of ubiquinone, a molecule with a key role in...
Research Article | Molecular Biology and PhysiologyPersistent DNA Damage Foci and DNA Replication with a Broken Chromosome in the African TrypanosomeChromosome damage must be repaired to prevent the proliferation of defective cells. Alternatively, cells with damage must be eliminated. This is true of human and several other cell types but may not be the case for single-celled parasites, such as trypanosomes. African trypanosomes, which cause lethal diseases in both humans and livestock, can actually exploit chromosomal damage to activate new surface coat proteins and to evade host...
Editor's Pick Research Article | Molecular Biology and PhysiologyDynamic Metabolic Rewiring Enables Efficient Acetyl Coenzyme A Assimilation in Paracoccus denitrificansCentral carbon metabolism provides organisms with energy and cellular building blocks during growth and is considered the invariable “operating system” of the cell. Here, we describe a new phenomenon in bacterial central carbon metabolism. In contrast to many other bacteria that employ only one pathway for the conversion of the central metabolite acetyl-CoA, Paracoccus...
Research Article | Molecular Biology and PhysiologyRadD Contributes to R-Loop Avoidance in Sub-MIC TobramycinBacteria frequently encounter low concentrations of antibiotics. Active antibiotics are commonly detected in soil and water at concentrations much below lethal concentration. Although sub-MICs of antibiotics do not kill bacteria, they can have a major impact on bacterial populations by contributing to the development of antibiotic resistance through mutations in originally sensitive bacteria or acquisition of DNA from resistant bacteria...
Research Article | Molecular Biology and PhysiologyIn Situ Conformational Changes of the Escherichia coli Serine Chemoreceptor in Different Signaling StatesIn Escherichia coli, membrane-bound chemoreceptors, the histidine kinase CheA, and coupling protein CheW form highly ordered chemosensory arrays. In core signaling complexes, chemoreceptor trimers of dimers undergo conformational changes, induced by ligand binding and sensory adaptation, which regulate kinase activation. Here, we characterize by cryo-electron...
Research Article | Molecular Biology and PhysiologyDay/Night Separation of Oxygenic Energy Metabolism and Nuclear DNA Replication in the Unicellular Red Alga Cyanidioschyzon merolaeEukaryotes acquired chloroplasts through an endosymbiotic event in which a cyanobacterium or a unicellular eukaryotic alga was integrated into a previously nonphotosynthetic eukaryotic cell. Photosynthesis by chloroplasts enabled algae to expand their habitats and led to further evolution of land plants. However, photosynthesis causes greater oxidative stress than mitochondrion-based respiration. In seed plants, cell division is...
Research Article | Molecular Biology and PhysiologyThe Stringent Response Inhibits DNA Replication Initiation in E. coli by Modulating Supercoiling of oriCTo survive bouts of starvation, cells must inhibit DNA replication. In bacteria, starvation triggers production of a signaling molecule called ppGpp (guanosine tetraphosphate) that helps reprogram cellular physiology, including inhibiting new rounds of DNA replication. While ppGpp has been known to block replication initiation in Escherichia coli for decades, the...