Antimicrobial resistance (AMR) is currently one of the most important challenges to the treatment of bacterial infections. A critical issue to combat AMR is to restrict its spread. In several instances, bacterial plasmids are involved in the global spread of AMR. Plasmids belonging to the incompatibility group (Inc)HI are widespread in Enterobacteriaceae and most of them express multiple antibiotic resistance determinants. They play a relevant role in the recent spread of colistin resistance. We present in this report novel findings regarding IncHI plasmid conjugation. Conjugative transfer in liquid medium of an IncHI plasmid requires expression of a plasmid-encoded, large-molecular-mass protein that contains an Ig-like domain. The protein, termed RSP, is encoded by a gene (ORF R0009) that maps in the Tra2 region of the IncHI1 R27 plasmid. The RSP protein is exported outside the cell by using the plasmid-encoded type IV secretion system that is also used for its transmission to new cells. Expression of the protein reduces cell motility and enables plasmid conjugation. Flagella are one of the cellular targets of the RSP protein. The RSP protein is required for a high rate of plasmid transfer in both flagellated and nonflagellated Salmonella cells. This effect suggests that RSP interacts with other cellular structures as well as with flagella. These unidentified interactions must facilitate mating pair formation and, hence, facilitate IncHI plasmid conjugation. Due to its location on the outer surfaces of the bacterial cell, targeting the RSP protein could be a means of controlling IncHI plasmid conjugation in natural environments or of combatting infections caused by AMR enterobacteria that harbor IncHI plasmids.

Quartzite was the second most‐often used lithic raw material in Europe in the Palaeolithic. However, this rock has not been characterized fully from the geo‐archaeological point of view. This study characterizes, defines and determines types of quartzite in northern Spain through a methodology that integrates petrography, digital image processing and X‐ray fluorescence. As a methodological foundation for the characterization of the material, it aims to open the possibility of discovering mechanisms of mobility, selection and management of quartzite by prehistoric societies. The types determined, based on the petrogenesis of the material, enable a better understanding of the archaeological sites of El Arteu and El Habario in the context of northern Spain in the Middle Palaeolithic.

Several isolated studies have tried to understand quartzite from an archaeological perspective by applying two different methodological approaches. The first one is based on non-destructive characterisation, aiming to understand human procurement and management of quartzite, without solid geoarchaeological criteria. The second characterised the material from archaeological sites using only petrographic or geochemical perspectives of a limited sample. Currently, both perspectives are unconnected, creating a methodological gap that needs to be solved to study the procurement and management of quartzite in greater depth. The present study, mainly methodological, will explore the gap between petrographic analysis and non-destructive characterisation. Doing so, we could fill this vacuum of information and generate a solid geoarchaeological basis to characterise not only a sample but complete assemblages. To this end, we analyse the lithic assemblages at El Arteu and El Habario, two Middle-Palaeolithic sites in the Cantabrian Region, northern Spain. We summarise the main results derived from petrographic analysis, but especially we will focus on non-destructive criteria to characterise the lithic surfaces of archaeological quartzite using stereoscope microscopy. This process allows us to understand the complete assemblage but also, through technological characterisation, understand the management of different quartzite petrogenetic types in both sites.

Global regulators such as H-NS play key relevant roles enabling bacterial cells to adapt to a changing environment. H-NS modulates both core and horizontally transferred (HGT) genes, but the mechanism by which H-NS can differentially regulate these genes remains to be elucidated. There are several instances of bacterial cells carrying genes that encode homologues of the global regulators. The question is what the roles of these proteins are. We noticed that the enteroaggregative E. coli strain 042 carries a new hitherto uncharacterized copy of the hns gene. We decided to investigate why this pathogenic E. coli strain requires an extra H-NS paralogue, termed H-NS2. In our work, we show that H-NS2 displays specific expression and regulatory properties. H-NS2 targets a subset of H-NS-specific genes and may help to differentially modulate core and HGT genes by the H-NS cellular pool.