A randomised investigation of journal responses to academic and journalist enquiry about possible scientific misconduct

No specific funding was received for this study. MB receives salary support from the Health Research Council of New Zealand. The Health Services Research Unit is funded by the Chief Scientist Office of the Scottish Government Health and Social Care Directorates. These funders had no role in the study design; collection, analysis, and interpretation of the data; writing of the report; and in the decision to submit the paper for publication.Peer reviewedPublisher PD

Mitochondria mediate septin cage assembly to promote autophagy of Shigella.

Septins, cytoskeletal proteins with well-characterised roles in cytokinesis, form cage-like structures around cytosolic Shigella flexneri and promote their targeting to autophagosomes. However, the processes underlying septin cage assembly, and whether they influence S. flexneri proliferation, remain to be established. Using single-cell analysis, we show that the septin cages inhibit S. flexneri proliferation. To study mechanisms of septin cage assembly, we used proteomics and found mitochondrial proteins associate with septins in S. flexneri-infected cells. Strikingly, mitochondria associated with S. flexneri promote septin assembly into cages that entrap bacteria for autophagy. We demonstrate that the cytosolic GTPase dynamin-related protein 1 (Drp1) interacts with septins to enhance mitochondrial fission. To avoid autophagy, actin-polymerising Shigella fragment mitochondria to escape from septin caging. Our results demonstrate a role for mitochondria in anti-Shigella autophagy and uncover a fundamental link between septin assembly and mitochondria

Investigation of Regulatory and Functional Diversification of Arabidopsis thaliana Shikimate Kinase Duplicates

Two Arabidopsis thaliana shikimate kinases, AtSK1 and AtSK2, were previously identified as having arisen from a duplication event 40-60 million years ago and are both believed to function in the shikimate pathway. We investigated the homologs have acquired divergent regulatory or functional roles since duplication. AtSK1 demonstrates different transcript levels than AtSK2 during heat shock and in floral tissues as determined by RT-PCR. Mining of publically available microarray datasets identified HSF1 and MYB family transcription factors as possible regulators of AtSK1 under these conditions. Heat shock response did not appear to be affected by either sk1 or sk2 knockouts in assays measuring thermotolerance and ROS production. Floral morphology appears normal during floral stages corresponding with AtSK1 transcript induction however, pollen viability is reduced by 20% in sk1 knockouts as measured by FDA staining. Thus, this work has identified instances of differential regulation and function between two recently duplicated shikimate kinases.MAS

Loss of elongation factor P disrupts bacterial outer membrane integrity

Elongation factor P (EF-P) is posttranslationally modified at a conserved lysyl residue by the coordinated action of two enzymes, PoxA and YjeK. We have previously established the importance of this modification in Salmonella stress resistance. Here we report that, like poxA and yjeK mutants, Salmonella strains lacking EF-P display increased susceptibility to hypoosmotic conditions, antibiotics, and detergents and enhanced resistance to the compound S-nitrosoglutathione. The susceptibility phenotypes are largely explained by the enhanced membrane permeability of the efp mutant, which exhibits increased uptake of the hydrophobic dye 1-N-phenylnaphthylamine (NPN). Analysis of the membrane proteomes of wild-type and efp mutant Salmonella strains reveals few changes, including the prominent overexpression of a single porin, KdgM, in the efp mutant outer membrane. Removal of KdgM in the efp mutant background ameliorates the detergent, antibiotic, and osmosensitivity phenotypes and restores wild-type permeability to NPN. Our data support a role for EF-P in the translational regulation of a limited number of proteins that, when perturbed, renders the cell susceptible to stress by the adventitious overexpression of an outer membrane porin