Andrés Corral Lugo

• PhD
• Merie Curie Postdoc at IGDR

Outer membrane vesicles (OMVs) are nanostructures derived from the outer membrane of Gram-negative bacteria. We previously demonstrated that vaccination with endotoxin-free OMVs isolated from an Acinetobacter baumannii strain lacking lipooligosaccharide (LOS) biosynthesis, due to a mutation in lpxD, provides full protection in a murine sepsis model...

The emergence and global dissemination of bacterial strains from numerous species with resistance to multiple antibiotic classes has increased in recent years, both in the healthcare and the community setting [...]

Mutations leading to upregulation of efflux pumps can produce multiple drug resistance in the pathogen Pseudomonas aeruginosa. Changes in their DNA binding regions, i.e., palindromic operators, can compromise pump depression and subsequently enhance resistance against several antibacterials and biocides. Here, we have identified (pseudo)palindromic...

Uncharacterized proteins have been underutilized as targets for the development of novel therapeutics for difficult-to-treat bacterial infections. To facilitate the exploration of these proteins, 2819 predicted, uncharacterized proteins (19.1% of the total) from reference strains of multidrug Acinetobacter baumannii, Klebsiella pneumoniae, and Pseu...

Wild bacteria, from the open ocean to the gut, experience persistent nutrient limitation. This fundamentally affects bacterial physiology and metabolism and has profound impacts on their infection by bacterial viruses (bacteriophages). For virulent bacteriophages, which cannot enter a lysogenic state, this poses a problem for environmental persiste...

The development of versatile and sensitive biotools to quantify specific SARS‐CoV‐2 immunoglobulins in SARS‐CoV‐2 infected and non‐infected individuals, built on the surface of magnetic microbeads functionalized with nucleocapsid (N) and in‐house expressed recombinant spike (S) proteins is reported. Amperometric interrogation of captured N‐ and S‐s...

The development of versatile and sensitive biotools to quantify specific SARS‐CoV‐2 immunoglobulins in SARS‐CoV‐2 infected and non‐infected individuals, built‐on the surface of magnetic microbeads functionalized with nucleocapsid (N) and in‐house expressed recombinant spike (S) proteins is reported. Amperometric interrogation of captured N‐ and S‐s...

Inactivation of the lipooligosaccharide (LOS) biosynthesis genes lpxA, lpxC and lpxD by ISAba insertion elements results in high-level resistance to colistin in A. baumannii. In the present study, we quantify the rate of spontaneous insertional inactivation of LOS biosynthesis genes by ISAba elements in the ATCC 19606-type strain and two multidrug...

Antimicrobial resistance is a major threat to global public health. Vaccination is an effective approach for preventing bacterial infections, however it has not been successfully applied to infections caused by some of the most problematic multidrug resistant pathogens. In this review, the potential for vaccines to contribute to reducing the burden...

The efficacy of SARS-CoV-2 nucleic acid-based vaccines may be limited by proteolysis of the translated product due to anomalous protein folding. This may be the case for vaccines employing linear SARS-CoV-2 B-cell epitopes identified in previous studies since most of them participate in secondary structure formation. In contrast, we have employed a...

Introduction Several plant-beneficial bacteria have the capability to promote the growth of plants through different mechanisms. The survival of such bacteria could be affected by environmental abiotic factors compromising their capabilities of phytostimulation. One of the limiting abiotic factors is low water availability. Materials and Methods I...

The present invention is related to a massive, fast and efficient methodology of counting bacteria in the laboratory from various samples; both environmental and human fluids. For its realization, it is not necessary expensive technology, or sophisticated devices, so it is also considered an economical and easy to use procedure. The quantification...

Genome analyses indicate that many bacteria possess an elevated number of chemoreceptors, suggesting that these species are able to perform chemotaxis to a wide variety of compounds. The scientific community is now only beginning to explore this diversity and to elucidate the corresponding physiological relevance. The discovery of histamine chemota...

The interference of plant compounds with bacterial quorum sensing (QS) is a major mechanism through which plants and bacteria communicate. However, little is known about the modes of action and effects on signal integrity during this type of communication. We have recently shown that the plant compound rosmarinic acid (RA) specifically binds to the...

Many bacteria can move chemotactically to a variety of compounds and the recognition of chemoeffectors by the chemoreceptor ligand binding domain (LBD) defines the specificity of response. Many chemoreceptors were found to recognize different amino- and organic acids, but the McpU chemoreceptor from Pseudomonas putida was identified as the first ch...

Bacteria from rhizosphere have the potential to promote the growth of plants, and could be used as inoculants to increase the crop profitability. However, under drought stress conditions, the number of bacteria associated to seeds could decrease below the minimal number of bacteria required to obtain a positive plant response. At the present work,...

Determination of bacteria susceptible to desiccation

In contrast to Escherichia coli, glucose metabolism in pseudomonads occurs exclusively through the Entner-Doudoroff (ED) pathway. This pathway, as well as the three routes to generate the initial ED pathway substrate, 6-phosphogluconate, are regulated by the PtxS, HexR and GtrS/GltR systems. With GntR (PA2320) we report here the identification of a...

Quorum sensing systems are essential for bacterial communication. We report here the purification and characterization of the Pseudomonas aeruginosa LasR quorum sensing regulator purified from lysates of E. coli cultures grown in the absence of added acyl-homoserine lactones (AHL). We show by isothermal titration calorimetry that LasR recognizes di...

Many bacterial signal transduction processes are initiated by the recognition of signal molecules by sensor proteins. However, most of the sensor proteins are functionally unannotated and their cognate ligands remain unknown, which represents currently a major bottleneck. To identify ligand that bind to chemoreceptors, we have been using in vitro l...

Apart from inter-bacteria communication quorum sensing (QS) mechanisms also enable interdomain interactions. To interfere with bacterial QS, plants were found to secrete compounds; most of which of unknown identity. We have identified the plant compound rosmarinic acid (RA) to modulate Pseudomonas aeruginosa QS by binding to the RhlR QS regulator....

Bacteria have evolved a variety of different signal transduction mechanisms. However, the cognate signal molecule for the very large amount of corresponding sensor proteins is unknown and their functional annotation represents a major bottleneck in the field of signal transduction. The knowledge of the signal molecule is an essential prerequisite t...

Quorum sensing is a bacterial communication mechanism that controls genes, enabling bacteria to live as communities, such as biofilms. Homoserine lactone (HSL) molecules function as quorum-sensing signals for Gram-negative bacteria. Plants also produce previously unidentified compounds that affect quorum sensing. We identified rosmarinic acid as a...

While it is well established that one- and two-component regulatory systems participate in regulating biofilm formation, there also exists evidence suggesting that chemosensory pathways are also involved. However, little information exists about which chemoreceptors and signals modulate this process. Here we report the generation of the complete se...

Chemotaxis is an essential mechanism that enables bacteria to move towards favorable ecological niches. Escherichia coli, the historical model organism for studying chemotaxis, has five well-studied chemoreceptors. However, many bacteria with different lifestyle have more chemoreceptors, most of unknown function. Using a high throughput screening a...

Chemoreceptors are at the beginning of chemosensory pathways that mediate chemotaxis. Pseudomonas putida KT2440 is predicted to have 27 chemoreceptors, most of which uncharacterised. We have previously identified McpS as chemoreceptor for Krebs cycle intermediates. Citrate is primarily present in the environment as metal-complex, which, however, is...

The PctC chemoreceptor of Pseudomonas aeruginosa mediates chemotaxis with high specificity to gamma-aminobutyric acid (GABA). This compound is present everywhere in nature and has multiple functions, including being a human neurotransmitter or plant signaling compound. Because P. aeruginosa is ubiquitously distributed in nature and able to infect a...

130 Abstract: An alternative for increasing the yield of crops is the use of PGPR, for this purpose the colonization is a critical process. In this work the chemotaxis toward tomato plants and bacteria colonization were evaluated for P. putida KT2440 and mutant strains in specific chemoreceptors for GABA and succinato. Axenic seedlings of three day...

Life is based on the specific interaction of molecules and the study of molecular recognition is therefore of fundamental importance. A number of different techniques have been developed to characterize binding events. Amongst these is isothermal titration calorimetry (ITC) in which heat changes caused by ligand binding are monitored. ITC is becomi...

A primary driving force during bacterial evolution was the capacity to access compounds necessary for growth and survival. Since the species of the genus Pseudomonas are characterized by metabolic versatility, these bacteria have developed chemotactic behaviors towards a wide range of different compounds. The specificity of a chemotactic response i...

Isothermal titration calorimetry (ITC) is based on a simple titration of one ligand with another and the small heat changes caused by the molecular interaction are detected. From one ITC experiment the complete set of thermodynamic parameters of binding including association and dissociation constants as well as changes in enthalpy, entropy, and fr...

Methyltransferases of the CheR family and methylesterases of the CheB family control chemoreceptor methylation, and this dynamic posttranslational modification is necessary for proper chemotaxis of bacteria. Studies with enterobacteria that contain a single CheR or CheB show that, in addition to binding at the methylation site, some chemoreceptors...

In an attempt to quantify the number of bacteria present in a high number of samples, routine procedures are usually very time-consuming. During this period of time, bacterial population could be modified. In this work, an alternative for a mas-sive, quick and economic method was evaluated in order to count viable bacteria, consisting in the sealin...

Título en ingles: Quantification of cultivable bacteria by the “Massive Stamping Drop Plate” method Resumen: Cuando se desea cuantificar el número de bacterias presentes en múltiples muestras, los procedimientos de rutina suelen consumir mucho tiempo. En ese periodo las muestras podrían sufrir modificaciones en su población. En el presente trabajo...