J Immunol Methods 1998,221(1–2):35–41.PubMedCrossRef Conflicts of interests Patents for the in vitro and in vivo use of EndoS have been applied for by Genovis AB and Hansa Medical AB, respectively. MC is listed as inventor on these applications that are pending.

Hansa Medical AB in part funded this study, but had no influence on the design of study, interpretation of data, or the final form of the manuscript. MC is a part time scientific consultant for Hansa Medical AB. Authors’ contributions JS participated in the CP-690550 solubility dmso design of the study, performed experiments and drafted the manuscript. MC and VN conceived of the study. CO performed experiments. AH designed the study and performed experiments. All authors read and approved the final manuscript.”
“Background Genes that are highly conserved between different types of organisms code for important biological functions and are therefore usually well studied and described. One group of conserved genes whose function has remained enigmatic until recently is the Kae1(OSGEP)/YgjD

family. Genes from this family occur in almost all bacterial, RG7112 order archaeal and eukaryotic genomes. The gene family consists of two groups: one group, GCP1/OSGEPL/Qri7, is of bacterial origin, the other, GCP2/OSGEP/Kae, is supposed to originate from archaea [1]. In Escherichia coli, Kae1/YgjD is essential for viability [2, 3]; in Arabidopsis thaliana and Saccharomyces cerevisia, deletion mutants exhibit deleterious phenotypes [4–6]. A biochemical activity for YgjD has recently been described: as already suggested by [7], Srinivasan and colleagues [8] showed that Kae1/YgjD protein (of Saccharomyces cerevisiae and Escherichia Mannose-binding protein-associated serine protease coli, respectively) is required to add a threonyl carbamoyl adenosine (t6A) modification to a subset of tranfer-RNAs that recognize codons with an adenin at the first position. Transfer-RNAs undergo complex modifications and maturation steps [9] required for translational fidelity [10–12]. Mutations in these modification pathways can be lethal or cause severe defects [13–15], and the involved genes are highly conserved in different organisms [14–16]. Because ygjD is

essential, it is not possible to delete the gene and study the phenotypic consequences. As an alternative, one can put the gene under control of an inducible promoter, and investigate the consequence of turning off its expression, and thereby depleting the YgjD protein. Our aim here is to get insights into the morphological changes that come about when the YgjD protein is depleted from growing Escherichia coli cells. In two studies ([3] and [17]), the authors have noticed an effect on cell size in YgjD depletion strains, suggesting a role of YgjD for cell division and/or cellular elongation. However, while Katz et al. observed shorter cells under YgjD depletion conditions, Handford et al. observed a mixed population of elongated and short cells.