Cristina Solano

• Public University of Navarre

The overuse of antibiotics in humans and livestock has driven the emergence and spread of antimicrobial resistance and has therefore prompted research on the discovery of novel antibiotics. Complestatin (Cm) and corbomycin (Cb) are glycopeptide antibiotics with an unprecedented mechanism of action that is active even against methicillin-resistant a...

Staphylococcus aureus is a leading cause of prosthetic joint infections (PJI). Surface adhesins play an important role in the primary attachment to plasma proteins that coat the surface of prosthetic devices after implantation. Previous efforts to identify a genetic component of the bacterium that confers an enhanced capacity to cause PJI have focu...

Contribution of genetic variations in the regulatory region of surface adhesin encoding genes to colonization of prosthetic implants by Staphylococcus aureus

Staphylococcus aureus is a leading cause of prosthetic joint infections (PJI) characterized by bacterial biofilm formation and recalcitrance to immune-mediated clearance and antibiotics. The molecular events behind PJI infection are yet to be unraveled. In this sense, identification of polymorphisms in bacterial genomes may help to establish associ...

Two-component systems (TCSs) are a prominent sensory system in bacteria. A prototypical TCS comprises a membrane-bound sensor histidine kinase (HK) responsible for sensing the signal and a cytoplasmic response regulator (RR) that controls target gene expression. Signal binding activates a phosphotransfer cascade from the HK to the RR. As a result,...

Plasmids have largely contributed to the spread of antimicrobial resistance genes among Staphylococcus strains. Knowledge about the fitness cost that plasmids confer on clinical staphylococcal isolates and the coevolutionary dynamics that drive plasmid maintenance is still scarce. In this study, we aimed to analyze the initial fitness cost of plasm...

Several dinucleotide cyclases, including cyclic GMP-AMP synthase, and their involvement in STING-mediated immunity have been extensively studied. In this study, we tested five bacterial diguanylate cyclases from the Gram-negative bacterium Salmonella Enteritidis, identifying AdrA as the most potent inducer of a STING-mediated IFN response. AdrA wil...

Abstract Salmonellosis is the second most common food-borne zoonosis in the European Union, with pigs being a major reservoir of this pathogen. Salmonella control in pig production requires multiple measures amongst which vaccination may be used to reduce subclinical carriage and shedding of prevalent serovars, such as Salmonella enterica serovar T...

Bacterial biofilms provide high cell density and a superior adaptation and protection from stress conditions compared to planktonic cultures, making them a very promising approach for bioremediation. Several Rhodococcus strains can desulfurize dibenzothiophene (DBT), a major sulphur pollutant in fuels, reducing air pollution from fuel combustion. D...

This is part 3.1 of the "Fluorescent Molecular Beacons Mimicking RNA Secondary Structures to Study RNA Chaperone Activity" collection of protocols. Collection Abstract: Molecular beacons (MBs) are oligonucleotide probes with a hairpin-like structure that are typically labelled at the 5' and 3' ends with a fluorophore and a quencher dye, respectivel...

This is part 3.2 of the "Fluorescent Molecular Beacons Mimicking RNA Secondary Structures to Study RNA Chaperone Activity" collection of protocols. Collection Abstract: Molecular beacons (MBs) are oligonucleotide probes with a hairpin-like structure that are typically labelled at the 5' and 3' ends with a fluorophore and a quencher dye, respectivel...

Molecular beacons (MBs) are oligonucleotide probes with a hairpin-like structure that are typically labelled at the 5' and 3' ends with a fluorophore and a quencher dye, respectively. The conformation of the MB acts as a switch for fluorescence emission. When the fluorophore is in close proximity to the quencher, fluorescence emission cannot be det...

Bacteria use two-component systems (TCSs) to sense and respond to their environments. Free-living bacteria usually contain dozens of TCSs, each of them responsible for sensing and responding to a different range of signals. Differences in the content of two-component systems are related with the capacity of the bacteria to colonize different niches...

Molecular beacons (MBs) are oligonucleotide probes with a hairpin-like structure that are typically labelled at the 5′ and 3′ ends with a fluorophore and a quencher dye, respectively. The conformation of the MB acts as a switch for fluorescence emission. When the fluorophore is in close proximity to the quencher, fluorescence emission cannot be det...

Significance In bacteria, functionally related genes are often cotranscribed in a single mRNA molecule under the same upstream promoter, forming a polycistronic operon unit. With this strategy, bacteria guarantee that production of all proteins related to a specific cellular process is simultaneously switched on or off. Here, we report the identifi...

Two-component systems (TCS) are modular signal transduction pathways that allow cells to adapt to prevailing environmental conditions by modifying cellular physiology. Staphylococcus aureus has 16 TCSs to adapt to the diverse microenvironments encountered during its life cycle, including host tissues and implanted medical devices. S. aureus is part...

Bacteria use two-component systems (TCSs) to sense and respond to environmental changes. The core genome of the major human pathogen Staphylococcus aureus encodes 16 TCSs, one of which (WalRK) is essential. Here we show that S. aureus can be deprived of its complete sensorial TCS network and still survive under growth arrest conditions similarly to...

Despite the number of examples that correlate interspecies interactions in polymicrobial infections with variations in pathogenicity and antibiotic susceptibility of individual organisms, antibiotic therapies are selected to target the most relevant pathogen, with no consideration of the consequences that the presence of other bacterial species may...

RNA-binding proteins (RBPs) are essential to fine-tune gene expression. RBPs containing the cold-shock domain are RNA chaperones that have been extensively studied. However, the RNA targets and specific functions for many of them remain elusive. Here, combining comparative proteomics and RBP-immunoprecipitation-microarray profiling, we have determi...

Many bacteria build biofilm matrices using a conserved exopolysaccharide named PGA or PNAG (poly-β-1,6-N-acetyl-D-glucosamine). Interestingly, while E. coli and other members of the family Enterobacteriaceae encode the pgaABCD operon responsible for PGA synthesis, Salmonella lacks it. The evolutionary force driving this difference remains to be det...

Strains and plasmids used in this study. (PDF)

Analysis of PGA synthesis dependence on c-di-GMP. Quantification of PGA exopolysaccharide production by dot blot. Serial dilutions (1/10) of the samples were spotted onto nitrocellulose membranes and PGA production was detected with specific anti PIA/PNAG antibodies. UD; undiluted sample. (A) Dot blot analysis of the PGA accumulated by S. Enteritid...

Oligonucleotides used in this study. (PDF)

Strains WT PphoP::adrA and ΔbcsA PphoP::adrA PcL::pga produce cellulose and PGA, respectively, in a phoP dependent fashion. A cellulose based biofilm is produced by WT PphoP::adrA after overnight growth in low-Mg2+ liquid medium (top panel). An aggregate of ΔbcsA PphoP::adrA PcL::pga bacteria can be observed at the bottom of the tube as Mg2+ concen...

Fitness of ΔbcsA versus the wild type or ΔbcsA PcL::pga strains. The competitive fitness of ΔbcsA in co-culture with either the wild type or ΔbcsA PcL::pga was determined by combining the two strains in LB broth, incubating at 37°C and enumerating each strain over time. (EPS)

Gene neighborhood analysis for pgaA, as provided in the STRING database [36]. Results for Enterobacteriaceae genomes are fully displayed, while those from other groups are presented in a collapsed mode. (EPS)

Hydrophobicity analysis of macrocolony biofilms formed by WT PcL::adrA and ΔbcsA PcL::adrA pJET::pga. (A) The cellulose overproducing strain, WT PcL::adrA, the PGA overproducing strain, ΔbcsA PcL::adrA pJET::pga and the control strain, ΔbcsA PcL::adrA, were incubated on LB agar or LB agar Cb media for 48h at 28°C. A bent tip was used to visualize t...

Synthesis of PGA by a Salmonella strain that constitutively expresses the pgaABCD operon from the chromosome. Comparison of the PGA accumulated by WT PcL::pga and WT pJET::pga, expressing the pgaABCD operon from the chromosome or from a plasmid, respectively, after 24 hours of growth at 37°C in LB or LB Cb media. Serial dilutions (1/10) of the samp...

PGA is overproduced by E. coli MG1655 when the pgaABCD operon is expressed from a constitutive promoter. Dot blot analysis of the PGA accumulated by E. coli MG1655, a pgaC mutant and a derivative of E. coli MG1655 in which the pgaABCD operon was placed under the control of the constitutive promoter PcL, after 24 hours of growth at 37°C in LB media....

Phylogenetic trees of the analyzed proteins. First column indicates the protein name, and the second column is the phylogenetic tree in standard newick format. Labels indicate species names, as retrieved from NCBI, followed by an underscore separator and the gene identifier. (PDF)

Salmonellosis is one of the most important bacterial zoonotic diseases transmitted through the consumption of contaminated food, with chicken and pig related products being key reservoirs of infection. Although numerous studies on animal vaccination have been performed in order to reduce Salmonella prevalence, there is still a need for an ideal vac...

Representative IFN-γ and TNF-α/CD4 staining for ΔXIII stimulated splenocytes. 28 days after immunization, splenocytes from control and ΔXIII immunized mice were plated and stimulated for 6 hours with medium, 106 or 107 cfu of heat-killed ΔXIII bacteria. Cells were surface stained with anti-CD4-FITC antibody and intracellularly stained with anti IFN...

Strains used in this study. (DOCX)

In the past 15 years, many efforts were made to create functionalized artificial surfaces showing special anti-bacterial and anti-biofouling properties. Thereby, the topography of medical relevant materials plays an important role. However, the targeted fabrication of promising surface structures like hole-, lamella- and pyramid-like patterns with...

Front Cover: Three-dimensional micrometer periodic structures generated by direct laser interference patterning (DLIP) on polystyrene surfaces have a profound effect on S. aureus adhesion. As demonstrated by J. Valle, I. Lasa, and co-workers on page 1060 pillar-like topographical patterns enhance S. aureus adhesion, whereas complex lamella microtop...

Modification of the biomaterial surface topography is a promising strategy to prevent bacterial adhesion and biofilm formation. In this study, we use direct laser interference patterning (DLIP) to modify polystyrene surface topography at sub-micrometer scale. The results revealed that three-dimensional micrometer structures have a profound impact o...

Biofilm development and quorum sensing (QS) are closely interconnected processes. Biofilm formation is a cooperative group behaviour that involves bacterial populations living embedded in a self-produced extracellular matrix. QS is a cell-cell communication mechanism that synchronizes gene expression in response to population cell density. Intuitiv...

The Staphylococcus aureus biofilm mode of growth is associated with several chronic infections that are very difficult to treat due to the recalcitrant nature of biofilms to clearance by antimicrobials. Accordingly, there is an increasing interest in preventing the formation of S. aureus biofilms and developing efficient anti-biofilm vaccines. Give...

The presence of regulatory sequences in the 3' untranslated region (3'-UTR) of eukaryotic mRNAs controlling RNA stability and translation efficiency is widely recognized. In contrast, the relevance of 3'-UTRs in bacterial mRNA functionality has been disregarded. Here, we report evidences showing that around one-third of the mapped mRNAs of the majo...

Biofilm development is recognized as a major virulence factor underlying most chronic bacterial infections. When a biofilm community is established, planktonic cells growing in the surroundings of a tissue switch to a sessile lifestyle and start producing a biofilm matrix. The initial steps of in vivo biofilm development are poorly characterized an...

Cyclic di-GMP (c-di-GMP) is a secondary messenger that controls a variety of cellular processes including the switch between a biofilm and a planktonic bacterial lifestyle. This nucleotide binds to cellular effectors in order to exert its regulatory functions. In Salmonella, two proteins, BcsA and YcgR, both of them containing a c-di-GMP binding Pi...

Competition index of Δbap-Wt and Δbap-ΔrepBap strains in vitro. An equal number of bacteria of S. aureus V329 (Wt) and Δbap or Δbap and ΔrepBap were used to infected MAC-T epithelial cells. After 1 h infection, invasion efficiency was calculated as the number of cfu that survived to 2 h of gentamicin treatment. Statistical differences were determin...

Invasion of S. aureus Newman (Nw) and Newman_Bap complemented with plasmid pFNBA4 that expresses the fnbA gene to Vero cells and Vero cells transfected with pcDNA3gp96. After 1 h infection invasion values were calculated as the number of bacteria that survived to 2 h of gentamicin treatment. (EPS)

Effect of the presence of PIA/PNAG exopolysaccharidic biofilm matrix in S. aureus invasion capacity. A) Dot-blot analysis showing PIA/PNAG accumulation in S. aureus V329 and Δbap complemented with pSC18 and S. aureus ISP479r. Cell surface extracts were treated with proteinase K and spotted onto nitrocellulose filters diluted 1/10. PNAG production w...

The biofilm matrix, composed of exopolysaccharides, proteins, nucleic acids and lipids, plays a well-known role as a defence structure, protecting bacteria from the host immune system and antimicrobial therapy. However, little is known about its responsibility in the interaction of biofilm cells with host tissues. Staphylococcus aureus, a leading c...

The Rcs phosphorelay pathway is a complex signaling pathway involved in the regulation of many cell surface structures in enteric bacteria. In response to environmental stimuli, the sensor histidine kinase (RcsC) autophosphorylates and then transfers the phosphate through intermediary steps to the response regulator (RcsB), which, once phosphorylat...

RNA deep sequencing technologies are revealing unexpected levels of complexity in bacterial transcriptomes with the discovery of abundant noncoding RNAs, antisense RNAs, long 5' and 3' untranslated regions, and alternative operon structures. Here, by applying deep RNA sequencing to both the long and short RNA fractions (<50 nucleotides) obtained fr...

During the last few months, several pioneer genome-wide transcriptomic, proteomic and metabolomic studies have revolutionised the understanding of bacterial biological processes, leading to a picture that resembles eukaryotic complexity. Technological advances such as next-generation high-throughput sequencing and high-density oligonucleotide micro...

Salmonella is a group of food-transmitted pathogens which are of considerable significance to the food processing industry, and cause highly prevalent food-borne diseases over the world. Salmonellosis can be manifested as a number of disease syndromes that include gastroenteritis and typhoid fever. Both the World Health Organization and the Europea...

Staphylococcus aureus can establish chronic infections on implanted medical devices due to its capacity to form biofilms. Analysis of the factors that assemble cells into a biofilm has revealed the occurrence of strains that produce either a polysaccharide intercellular adhesin/poly-N-acetylglucosamine (PIA/PNAG) exopolysaccharide- or a protein-dep...

Bacteria have developed an exclusive signal transduction system involving multiple diguanylate cyclase and phosphodiesterase domain-containing proteins (GGDEF and EAL/HD-GYP, respectively) that modulate the levels of the same diffusible molecule, 3'-5'-cyclic diguanylic acid (c-di-GMP), to transmit signals and obtain specific cellular responses. Cu...

Staphylococcus aureus vaccines based on bacterins surrounded by slime, surface polysaccharides coupled to protein carriers and polysaccharides embedded in liposomes administered together with non-biofilm bacterins confer protection against mastitis. However, it remains unknown whether protective antibodies are directed to slime-associated known exo...

The capacity of Staphylococcus aureus to form biofilms on host tissues and implanted medical devices is one of the major virulence traits underlying persistent and chronic infections. The matrix in which S. aureus cells are encased in a biofilm often consists of the polysaccharide intercellular adhesin (PIA) or poly-N-acetyl glucosamine (PNAG). How...

To determine whether systemic immunization with plasmid DNA and virus vector against visna/maedi virus (VMV) would induce protective immune responses, sheep were immunized with VMV gag and/or env sequences using particle-mediated epidermal bombardment and injection of recombinant modified vaccinia Ankara. The results showed that immunization induce...

Sheep were immunized against Visna/Maedi virus (VMV) gag and/or env genes via the nasopharynx-associated lymphoid tissue (NALT) and lung using polyethylenimine (PEI)-DNA complexes and modified vaccinia Ankara, and challenged with live virus via the lung. env immunization enhanced humoral responses prior to but not after VMV challenge. Systemic T ce...

In small ruminant lentivirus infections, cellular immune responses are diminished in clinically affected animals. The underlying mechanisms for this are unknown. In this study, we tested the hypothesis that alterations in expression of the co-stimulatory molecules B7-1 and B7-2 are involved in infections with Visna/Maedi virus (VMV), the prototype...

Although exopolysaccharides are important and often essential compounds of the biofilm matrix, recent evidences suggest that a group of surface proteins plays a leading role during the development of the microbial communities. The first member of this group of proteins was described in a Staphylococcus aureus bovine mastitis isolate and was named B...

Small ruminant lentiviruses (SRLV) are widely spread in many countries, including Spain. However, little is known about the genetic characteristics of Spanish goat and sheep SRLV. In this study, segments from three genomic regions (pol, gag-p25 and LTR) were amplified using DNA isolated from three Spanish autochthonous sheep (one) and goats (two)....