Tino Krell

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Verified

Tino verified their affiliation via an institutional email.

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• PhD
• Professor at Spanish National Research Council

Chemotaxis pathways are among the most complex signaling systems in bacteria. A central feature of these pathways is the ternary complex formed by chemoreceptors, the autokinase CheA, and the coupling proteins CheW and CheV. Whereas CheW is present in all chemotaxis pathways, CheV is primarily found in bacteria that contain many chemoreceptors. Che...

Bacterial receptors feed into multiple signal transduction pathways that regulate a variety of cellular processes including gene expression, second messenger levels, and motility. Receptors are typically activated by signal binding to ligand-binding domains (LBDs). Cache domains are omnipresent LBDs found in bacteria, archaea, and eukaryotes, inclu...

Plant pathogens and plant-associated bacteria contain about twice as many chemoreceptors as the bacterial average, indicating that chemotaxis is particularly important for bacteria-plant interactions. However, information on the corresponding chemoreceptors is limited. In this study, we identified the chemoreceptor PacP from the phytopathogen Pecto...

Bacteria use chemotaxis to move to favorable ecological niches. For many pathogenic bacteria, chemotaxis is required for full virulence, particularly for the initiation of host colonization. There do not appear to be limits to the type of compounds that attract bacteria, and we are just beginning to understand how chemotaxis adapts them to their li...

Chemotaxis is the directed, flagellum-based movement of bacteria in chemoeffector gradients. Bacteria respond chemotactically to a wide range of chemoeffectors, including amino, organic, and fatty acids, sugars, polyamines, quaternary amines, purines, pyrimidines, aromatic hydrocarbons, oxygen, inorganic ions, or polysaccharides. Most frequent are...

Many chemoreceptors contain a C‐terminal pentapeptide at the end of a linker. In Escherichia coli, this pentapeptide forms a high‐affinity binding site for CheR and phosphorylated CheB, and its removal interferes with chemoreceptor adaptation. Analysis of chemoreceptors revealed significant variation in their pentapeptide sequences, and bacteria of...

Purines and their derivatives control intracellular energy homeostasis and nucleotide synthesis, and act as signaling molecules. Here, we combine structural and sequence information to define a purine-binding motif that is present in sensor domains of thousands of bacterial receptors that modulate motility, gene expression, metabolism, and second-m...

The communication between plants and their microbiota is highly dynamic and involves a complex network of signal molecules. Among them, the auxin indole-3-acetic acid (IAA) is a critical phytohormone that not only regulates plant growth and development, but is emerging as an important inter- and intra-kingdom signal that modulates many bacterial pr...

The canonical mode of receptor activation consists in the binding of signals or signal-loaded solute binding proteins (SBPs) to sensor domains. Many sensor histidine kinases (SHK), that are activated by SBP binding, are encoded next to their cognate sbp gene. To assess to what degree this is a general rule, we studied three SBPs of Pseudomonas aeru...

The standard method of receptor activation involves the binding of signals or signal‐loaded solute binding proteins (SBPs) to sensor domains. Many sensor histidine kinases (SHKs), which are activated by SBP binding, are encoded adjacent to their corresponding sbp gene. We examined three SBPs of Pseudomonas aeruginosa PAO1, encoded near the genes fo...

Bacterial receptors feed into multiple signal transduction pathways that regulate a variety of cellular processes including gene expression, second messenger levels and motility. Receptors are typically activated by signal binding to ligand binding domains (LBD). Cache domains are omnipresent LBDs found in bacteria, archaea, and eukaryotes, includi...

The capacity of chemotaxis pathways to respond to signal gradients relies on adaptation mediated by the coordinated action of CheR methyltransferases and CheB methylesterases. Many chemoreceptors contain a C-terminal pentapeptide at the end of a linker. In Escherichia coli, this pentapeptide forms a high-affinity binding site for CheR and phosphory...

Purines and their derivatives are key molecules for controlling intracellular energy homeostasis and nucleotide synthesis. In eukaryotes, including humans, purines also act as signaling molecules that mediate extracellular communication and control key cellular processes, such as proliferation, migration, differentiation, and apoptosis. However, th...

Bacteria have evolved multiple sensing strategies to efficiently adapt to their natural hosts and environments. In the context of plant pathology, chemotaxis allows phytopathogenic bacteria to direct their movement towards hosts through the detection of a landscape of plant‐derived molecules, facilitating the initiation of the infective process. Th...

Purines and their derivatives are key molecules for controlling intracellular energy homeostasis and nucleotide synthesis. In eukaryotes, including humans, purines also act as signaling molecules that mediate extracellular communication and control key cellular processes, such as proliferation, migration, differentiation, and apoptosis. However, th...

Bacteria possess various receptors that sense different signals and transmit information to enable an optimal adaptation to the environment. A major limitation in microbiology is the lack of information on the signal molecules that activate receptors. Signals recognized by sensor domains are poorly reflected in overall sequence identity, and theref...

The chemotaxis network, one of the most prominent prokaryotic sensory systems, is present in most motile bacteria and archaea. Although the conserved signaling core of this network is well characterized, ligand specificities of a large majority of diverse chemoreceptors encoded in bacterial genomes remain unknown. Here, we performed a systematic id...

Solute binding proteins (SBPs) are of central physiological relevance for prokaryotes. These proteins present substrates to transporters, but they also stimulate different signal transduction receptors. SBPs form a superfamily of at least 33 protein Pfam families. To assess possible links between SBP sequence and the ligand recognized, we have insp...

About half of the known bacterial species perform chemotaxis that gains them access to sites that are optimal for growth and survival. The motility apparatus and chemotaxis signaling pathway impose a large energetic and metabolic burden on the cell. There is almost no limit to the type of chemoeffectors that are recognized by bacterial chemorecepto...

Indole‐3‐acetic acid (IAA) is emerging as a key intra‐ and inter‐kingdom signal molecule that modulates a wide range of processes of importance during plant–microorganism interaction. However, the mechanisms by which IAA carries out its functions in bacteria as well as the regulatory processes by which bacteria modulate auxin production are largely...

Microorganisms are exposed in their natural niches to a wide diversity of signal molecules. Specific detection of these signals results in alterations in microbial metabolism and physiology. Auxins like indole‐3‐acetic acid are key phytohormones that regulate plant growth and development. Nonetheless, auxin biosynthesis is not restricted to plants...

Bacterial signal transduction systems are typically activated by the binding of signal molecules to receptor ligand binding domains (LBDs), such as the NIT LBD. We report here the identification of the NIT domain in more than 15,000 receptors that were present in 30 bacterial phyla, but also in 19 eukaryotic phyla, expanding its known phylogenetic...

The chemotaxis network, one of the most prominent prokaryotic sensory systems, is present in most motile bacteria and archaea. Although the conserved signaling core of the network is well characterized, ligand specificities of a large majority of diverse chemoreceptors encoded in bacterial genomes remain unknown. Here we performed a systematic iden...

Bacteria contain many different receptor families that sense different signals permitting an optimal adaptation to the environment. A major limitation in microbiology is the lack of information on the signal molecules that activate receptors. Due to a significant sequence divergence, the signal recognized by sensor domains is only poorly reflected...

Amino acids are important nutrients and also serve as signals for diverse signal transduction pathways. Bacteria use chemoreceptors to recognize amino acid attractants and to navigate their gradients. In Escherichia coli two likely paralogous chemoreceptors Tsr and Tar detect 9 amino acids, whereas in Pseudomonas aeruginosa the paralogous chemorece...

Chemosensory pathways and two-component systems are important bacterial signal transduction systems. In the human pathogen Pseudomonas aeruginosa, these systems control many virulence traits. Previous studies showed that inorganic phosphate (Pi) deficiency induces virulence. We report here the abundance of chemosensory and two-component signaling p...

Bacteria have evolved a sophisticated array of signal transduction systems that allow them to adapt their physiology and metabolism to changing environmental conditions. Typically, these systems recognize signals through dedicated ligand binding domains (LBDs) to ultimately trigger a diversity of physiological responses. Nonetheless, an increasing...

Nitrate metabolism plays an important role in bacterial physiology. During the interaction of plant pathogenic bacteria with its hosts, bacteria face variable conditions with respect to nitrate availability. Perception mechanisms through the chemosensory pathway drive the entry and control the colonization of plant host in phytopathogenic bacteria....

Antibiotics are our main weapons to fight pathogenic bacteria, but the increase in antibiotic-resistant strains and their consequences represents a major global health challenge, revealing the necessity to develop alternative antimicrobial strategies that do not involve the bacterial killing or growth inhibition. P. aeruginosa has been placed secon...

Based on genome analyses, it has been estimated that more than half of the bacteria have made an important investment into motility since they possess genes encoding the flagellar motor, the flagellum, chemosensory pathways and chemoreceptors. The metabolic burden associated with gene maintenance, protein synthesis and operating these systems is ve...

Demonstration of the pH robustness of extracytoplasmic sensing reveals a previously undescribed evolutionary mechanism that enables bacteria to monitor environmental changes under changing conditions. This mechanism includes the maintenance of the dimeric state of four-helixbundle ligand-binding domains (LBDs).

SBPs are essential components for many transporters, but multiple pieces of more recent evidence indicate that the SBP-mediated stimulation of different transmembrane receptors is a general and widespread signal transduction mechanism in bacteria. The double function of SBPs in coordinating transport with signal transduction remains to a large degr...

Bacteria have evolved multiple signal transduction systems that permit an adaptation to changing environmental conditions. Chemoreceptor-based signaling cascades are very abundant in bacteria and are among the most complex signaling systems. Currently, our knowledge on the molecular features that determine signal recognition at chemoreceptors is li...

Foliar bacterial pathogens have to penetrate the plant tissue and access the interior of the apoplast in order to initiate the pathogenic phase. The entry process is driven by chemotaxis towards plant‐derived compounds in order to locate plant openings. However, information on plant signals recognized by bacterial chemoreceptors is scarce. Here, we...

Bodhankar et al. reported a noncanonical sensing mechanism that involves signal interaction with the McpA chemoreceptor signaling domain resulting in a chemorepellence response of Bacillus subtilis . The identified repellent binding site is analogous to that for attractant binding in McpB, another B. subtilis chemoreceptor.

Shewanella spp. play important ecological and biogeochemical roles, due in part to their versatile metabolism and swift integration of stimuli. While Shewanella spp. are primarily considered environmental microbes, Shewanella algae is increasingly recognized as an occasional human pathogen. S. algae shares the broad metabolic and respiratory repert...

P. aeruginosa causes a significant number of deaths annually worldwide. For many pathogens, chemotaxis plays an import role in the initial stages of infection, and deciphering the key chomoeffectors and their cognate chemoreceptors may permit the development of strategies to inhibit this process.

Significance Amino acids are the building blocks of life and important signaling molecules. Despite their common structure, no universal mechanism for amino acid recognition by cellular receptors is currently known. We discovered a simple motif, which binds amino acids in various receptor proteins from all major life-forms. In humans, this motif is...

Supplementary Information

Indole-3-acetic acid (IAA) is the main naturally occurring auxin and is produced by organisms of all kingdoms of life. In addition to the regulation of plant growth and development, IAA plays an important role in the interaction between plants and growth-promoting and phytopathogenic bacteria by regulating bacterial gene expression and physiology....

The alarming rise in the emergence of antimicrobial resistance in human, animal and plant pathogens is challenging global health and food production. Traditional strategies used for antibiotic discovery persistently result in the re‐isolation of known compounds, calling for the need to develop more rational strategies to identify new antibiotics. A...

Chemosensory pathways are among the most abundant prokaryotic signal transduction systems, allowing bacteria to sense and respond to environmental stimuli. Signaling is typically initiated by the binding of specific molecules to the ligand binding domain (LBD) of chemoreceptor proteins (CRs). Although CRs play a central role in plant-microbiome int...

Bacteria have evolved many different signal transduction systems that sense signals and generate a variety of responses. Generally, most abundant are transcriptional regulators, sensor histidine kinases and chemoreceptors. Typically, these systems recognize their signal molecules with dedicated ligand-binding domains (LBDs), which, in turn, generat...

We report the complete genome sequence and base modification analysis of the Shewanella algae type strain CECT 5071 (= OK-1 = ATCC 51192 = DSM 9167 = IAM 14159). The genome is composed of a single chromosome of 4,924,764 bp, with a GC content of 53.10%.

Chemotaxis, the ability of motile bacteria to direct their movement in gradients of attractants and repellents, plays an important role during the rhizosphere colonization by rhizobacteria. The rhizosphere is a unique niche for plant–microbe interactions. Root exudates are highly complex mixtures of chemoeffectors composed of hundreds of different...

Bacteria have evolved sophisticated signaling mechanisms to coordinate interactions with organisms of other domains, such as plants, animals and human hosts. Several important signal molecules have been identified that are synthesized by members of different domains and that play important roles in inter-domain communication. In this article, we re...

Amino acids are recognized as signals by various receptors in bacteria, archaea, and eukaryotes. However, no common mechanism for amino acid recognition is currently known. Here we show that a subclass of a ubiquitous extracellular domain dCache_1 contains a simple amino acid recognition motif, and it is found throughout the Tree of Life. In bacter...

The solute binding proteins (SBPs) of prokaryotes are present in the extracytosolic space. Although their primary function is providing substrates to transporters, SBPs also stimulate different signaling proteins, including chemoreceptors, sensor kinases, diguanylate cyclases/phosphodiesterases and Ser/Thr kinases, thereby causing a wide range of r...

Although the soil bacterium Pseudomonas putida KT2440 bears a bona fide adenylate cyclase gene (cyaA), intracellular concentrations of 3',5'-cyclic adenosine monophosphate (cAMP) are barely detectable. By using reporter technology and direct quantification of cAMP under various conditions, we show that such low levels of the molecule stem from the...

Shewanella spp. possess a broad respiratory versatility, which contributes to the occupation of hypoxic and anoxic environmental or host-associated niches. Here, we observe a strain-specific induction of biofilm formation in response to supplementation with the anaerobic electron acceptors dimethyl sulfoxide (DMSO) and nitrate in a panel of Shewane...

Bacteria have evolved a variety of signal transduction mechanisms that generate different outputs in response to external stimuli. Chemosensory pathways are widespread in bacteria and are among the most complex signaling mechanisms, requiring the participation of at least six proteins. These pathways mediate flagellar chemotaxis, in addition to con...

Many bacteria possess multiple chemosensory pathways that are composed of homologous signaling proteins. These pathways appear to be functionally insulated from each other, but little information is available on the corresponding molecular basis. We report here a novel mechanism that contributes to pathway insulation. We show that, of the four CheB...

Signalling through chemosensory pathways is typically initiated by the binding of signal molecules to the chemoreceptor ligand binding domain (LBD). The PcaY_PP chemoreceptor from Pseudomonas putida KT2440 is characterized by an unusually broad signal range, and minimal requisites for signal binding are the presence of a C6‐membered ring and that o...

Chemosensory pathways represent a major prokaryotic signal transduction mechanism that is based on signal sensing by chemoreceptors. An essential feature of chemosensory pathways is the CheR and CheB mediated control of chemoreceptor methylation causing pathway adaptation. At their C-terminal extension the Tar and Tsr model chemoreceptors contain a...

Chemotaxis is based on the action of chemosensory pathways and is typically initiated by the recognition of chemoeffectors at chemoreceptor ligand binding domains (LBD). Chemosensory signaling is highly complex; aspect that is not only reflected in the intricate interaction between many signaling proteins but also in the fact that bacteria frequent...

Pseudomonas aeruginosa is an ubiquitous gram-negative opportunistic human pathogen which is not considered part of the human commensal gut microbiota. However, depletion of the intestinal microbiota (Dysbiosis) following antibiotic treatment facilitates the colonization of the intestinal tract by Multidrug-Resistant P. aeruginosa. One possible stra...

Many bacteria possess a large number of chemoreceptors that recognize a variety of different compounds. More than 60% of the genomes analyzed in this study contain paralogous chemoreceptors, suggesting that they emerge with high frequency. We provide first insight on how paralogous receptors have evolved and show that two chemoreceptors with a narr...

Solute binding proteins (SBPs) form a heterogeneous protein family that is found in all kingdoms of life. In bacteria, the ligand-loaded forms bind to transmembrane transporters providing the substrate. We present here the SBP repertoire of Pseudomonas aeruginosa PAO1 that is composed of 98 proteins. Bioinformatic predictions indicate that many of...

There is substantive evidence that chemotaxis is a key requisite for efficient pathogenesis in plant pathogens. However, information regarding particular bacterial chemoreceptors and the specific plant signal that they sense is scarce. Our work shows that the phytopathogenic bacterium Pseudomonas syringae pv. tomato mediates not only chemotaxis but...

Pseudomonas aeruginosa is an opportunistic human pathogen causing infections in a variety of plant and animal hosts. The gene mcpB, part of the chemosensory gene cluster II, encodes a soluble chemoreceptor whose function remains unknown. Previous studies show that the cheB2 gene, also located in the chemosensory cluster II, is involved in a specifi...

Chemotaxis and energy taxis permit directed bacterial movements in gradients of environmental cues. Nitrate is a final electron acceptor for anaerobic respiration and can also serve as a nitrogen source for aerobic growth. Previous studies indicated that bacterial nitrate taxis is mediated by energy taxis mechanisms, which are based on the cytosoli...

Plant root colonization by rhizobacteria can protect plants against pathogens and promote plant growth, and chemotaxis to root exudates was shown to be an essential prerequisite for efficient root colonization. Since many chemoattractants control the transcript levels of their cognate chemoreceptor genes, we have studied here the transcript levels...

The majority of clinically used antibiotics originate from bacteria. As the need for new antibiotics grows, large-scale genome sequencing and mining approaches are being used to identify novel antibiotics. However, this task is hampered by the fact that many antibiotic biosynthetic clusters are not expressed under laboratory conditions. One strateg...

Bacteria possess a large number of signal transduction systems that sense and respond to different environmental cues. Most frequently these are transcriptional regulators, two-component systems and chemosensory pathways. A major bottleneck in the field of signal transduction is the lack of information on signal molecules that modulate the activity...

Dear Colleagues, A chemotactic response is initiated by the chemoeffector-mediated stimulation of chemoreceptors. Although chemoreceptors are essential for chemotaxis, many of their features remain poorly understood. Bacterial genome analysis and experimental data show that chemoreceptors form a highly diverse protein super-family that differs in...

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...

Many bacteria have been isolated in the past that are able to live on toxic aromatic compounds as their sole carbon source. These strains are of great biotechnological interest for bioremediation purposes, since aromatic compounds are components of crude oil and are released, e.g., after a forest fire during the combustion of cellulose and lignins....

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...

Recalcitrant organic toxic chemicals have been accumulating for decades as a consequence of industrial activity. Concerns about environmental contamination have been rising in the last three decades and therefore the need for soil remediation has become a priority. Although physico/chemical techniques are currently the most efficient methods being...

Bacteria of the genus Pseudomonas are widespread in nature. In the last decades, members of this genus, especially Pseudomonas aeruginosa and Pseudomonas putida, have acquired great interest because of their interactions with higher organisms. Pseudomonas aeruginosa is an opportunistic pathogen that colonizes the lung of cystic fibrosis patients, w...

Two-component systems (TCS) exist in bacteria and archaea. In contrast to bacterial TCSs little information is available on their archaeal counterparts. In this issue Galperin and coworkers present a bioinformatics analysis of TCS genes from archaeal genome sequences. This study identified different aspects in which bacterial and archaeal TCS media...

The majority of bacterial chemoreceptors remain functionally un-annotated. The knowledge of chemoreceptor function, however, is indispensable to understanding the evolution of the chemotaxis system in bacteria with different lifestyles. Significant progress in the annotation of chemoreceptor function has been made using experimental strategies that...

The rhizosphere, defined as the volume of soil under the physical, chemical and biological influences of plant roots, is a region of enormous microbial diversity and activity. This microbial activity is essential for plant nutrition and health since it favours the uptake of nutrients by the plant and offers resistance against a wide range of plant...

Chemotaxis toward organic acids has been associated with colonization fitness and virulence and the opportunistic pathogen Pseudomonas aeruginosa exhibits taxis toward several tricarboxylic acid intermediates. In this study, we used high-throughput ligand screening and isothermal titration calorimetry to demonstrate that the ligand binding domain (...