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.

Studies on lithic resource management-mainly flint-by prehistoric groups south of the western Pyrenees have significantly increased during the past decades. These studies usually focus on identifying outcrops and characterising the different varieties found at archaeological sites. However, the understanding of mobility and territorial management patterns based on raw materials is still very limited and has only been tackled in terms of lineal distance. This paper proposes a methodological approach for the territorial analysis of flint distribution with the three following aims: 1) to determine the expansion ranges of each variety of flint from its outcrop; 2) to spatially relate these outcrops with archaeological sites; and 3) to improve our knowledge on the catchment strategies of Upper Palaeolithic groups. The methodological tool chosen to fulfil these objectives is the Geographic Information System (GIS), because it allows to relate spatially the flint outcrops and flint varieties identified at archaeological sites based on: 1) isocost maps showing the cost of expansion for each variety of flint across the territory built on topography; 2) the quantification of the cost of expansion using Cost Units (CU); and 3) the relationship between the percentage of each variety of flint at each archaeological site and the cost of accessing its outcrop. In order to demonstrate that cost is a powerful way to relate spatially raw material distribution and archaeological sites with outcrops, we contrasted its results with the ones obtained by more classic means (Euclidean distance and distance across the most optimal route). It was therefore shown that cost is better at explaining the spatial relationship between flint outcrops and archaeological sites, which, in turn, provides new data on catchment strategies, mobility patterns and territorial management of Upper Palaeolithic groups.

The genomes of Gram-negative bacteria encode paralogues and/or orthologues of global modulators. The nucleoid-associated H-NS and Hha proteins are an example: several enterobacteria such as Escherichia coli or Salmonella harbor H-NS, Hha and their corresponding paralogues, StpA and YdgT proteins, respectively. Remarkably, the genome of the pathogenic enteroaggregative E. coli strain 042 encodes, in addition to the hha and ydgT genes, two additional hha paralogues, hha2 and hha3. We show in this report that there exists a strong correlation between the presence of these paralogues and the virulence phenotype of several E. coli strains. hha2 and hha3 predominate in some groups of intestinal pathogenic E. coli strains (enteroaggregative and shiga toxin-producing isolates), as well as in the widely distributed extraintestinal ST131 isolates. Because of the relationship between the presence of hha2/hha3 and some virulence factors, we have been able to provide evidence for Hha2/Hha3 modulating the expression of the antigen 43 pathogenic determinants. We show that tracking global modulators or their paralogues/orthologues can be a new strategy to identify bacterial pathogenic clones and propose PCR amplification of hha2 and hha3 as a virulence indicator in environmental and clinical E. coli isolates.

In this report, we show that bacterial plasmids that harbor the Tn10 transposon (i.e., the IncHI1 plasmid R27) modify expression of different Salmonella regulons responding to the presence of tetracycline (Tc) in the medium. By using as a model the Tc-dependent upregulation of the ibpAB operon (which belongs to the heat shock regulon), we have identified Tn10-tetA (coding for a Tc efflux pump) and adjacent tetC sequences as required for ibpAB upregulation. Characterization of transcripts in the tetAC region showed that tetA transcription can continue into tetC sequences, generating a long 3'UTR sequence, which can protect transcripts from RNA processing, thus increasing the expression of TetA protein. In the presence of Tc, the DnaK and IbpA chaperones are overexpressed and translocated to the periplasm and to the membrane fraction respectively. DnaK targeting unfolded proteins is known to induce heat shock by avoiding RpoH proteolysis. We correlate expression levels of Tn10-encoded TetA protein with heat shock induction in Salmonella, likely because TetA activity compromises protein secretion.

RESUMENLos estudios referentes a la gestión de los recursos líticos -especialmente el sílex-por parte de los grupos prehistóricos en las dos vertientes del Pirineo occidental han aumentado de manera considerable en las últimas décadas. En este trabajo, pretendemos realizar una aproximación a la movilidad de los grupos superopaleolíticos, mediante los Sistemas de Información Geográfica (SIG). Estos nos permiten relacionar espacialmente los afloramientos de sílex y los restos líticos encontrados en los yacimientos arqueológicos. Para ello, hemos construido, a través de los Cost Distance Analysis, una serie de mapas que permiten detectar las dinámicas de expansión de cada uno de afloramientos, así como los patrones de aprovisionamiento de cada yacimiento. Adicionalmente, hemos relacionado los valores numéricos obtenidos del análisis espacial con la cantidad de sílex encontrado en cada nivel arqueológico a partir de estadística descriptiva y la aplicación de la lógica difusa. De esta forma hemos podido revisar los conceptos de autoctonía y aloctonía, así como plantear modelos generales de aprovisionamiento y distribución de sílex en la región. LABURPENAMendebaldeko Pirinioen bi isurialdeetan historiaurreko taldeek baliabide litikoen -batez ere silexa-inguruan eginiko kudeaketari buruzko azterlanak asko ugaritu dira azken hamarkadetan. Lan honetan, hurbiltze bat egin nahi diogu talde superopaleolitikoen mugikortasunari, Informazio Geografikoko Sistemen (GIS) bidez. Hala, espazioa kontuan hartuta lotu ditzakegu aztarnategi arkeologikoetan aurkitutako silexaren eta hondakin litikoen azaleratzeak. Horretarako, Cost Distance Analysis direlakoen bidez, zenbait mapa eraiki ditugu eta horiei esker, azaleratze bakoitzaren hedatze-dinamikak detektatu ditugu. Aztarnategi bakoitzaren hornitze-ereduak ere eraiki ditugu. Horrez gain, azterketa espazialaren emaitza gisa eskuratu ditugun zenbakizko balioak maila arkeologiko bakoitzean aurkitutako silex kantitatearekin lotu ditugu deskribapenezko estatistikatik abiatuta eta logika lausoa aplikatuta. Hala, autoktonia eta aloktonia kontzeptuak berraztertu ahal izan ditugu eta aipatutako eremuko hornitze-eredu orokorrak eta silexaren banaketa planteatu ditugu.