A5008983844- Vibrio bacteria research studies
- Bacterial biofilms and quorum sensing
- Aquaculture disease management and microbiota
- Escherichia coli research studies
- Legionella and Acanthamoeba research
- Antibiotic Resistance in Bacteria
- Molecular Communication and Nanonetworks
- Microbial Community Ecology and Physiology
- Child Nutrition and Water Access
- Evolutionary Game Theory and Cooperation
- Salmonella and Campylobacter epidemiology
- Immune Response and Inflammation
- Gene Regulatory Network Analysis
- Evolution and Genetic Dynamics
- Wireless Body Area Networks
- Bacterial Genetics and Biotechnology
- Energy Harvesting in Wireless Networks
- Sepsis Diagnosis and Treatment
- Bacillus and Francisella bacterial research
- Gut microbiota and health
- CRISPR and Genetic Engineering
- Microfluidic and Bio-sensing Technologies
- Aquatic Ecosystems and Phytoplankton Dynamics
- Slime Mold and Myxomycetes Research
- Advanced biosensing and bioanalysis techniques
Georgia Institute of Technology
2015-2024
University of Washington
2020
Centro Científico Tecnológico - Tandil
2019
Universidad Nacional del Centro de la Provincia de Buenos Aires
2019
Princeton University
2002-2014
AID Atlanta
2012
University of Michigan
1996-2002
NOAA Great Lakes Environmental Research Laboratory
1996
Rio Salado College
1995
Dartmouth–Hitchcock Medical Center
1994
Summary Multiple quorum‐sensing circuits function in parallel to control virulence and biofilm formation Vibrio cholerae . In contrast other bacterial pathogens that induce factor production and/or at high cell density the presence of autoinducers, V. represses these behaviours density. Consistent with this, we show here strains ‘locked’ regulatory state mimicking low are enhanced for whereas mutants incapable producing biofilms. The cascade have identified regulates transcription genes...
Legionella pneumophila survives in aquatic environments, but replicates within amoebae or the alveolar macrophages of immunocompromised individuals. Here, signal transduction pathway that co-ordinates L. virulence expression response to amino acid depletion was investigated. To facilitate kinetic and genetic studies, a phenotypic reporter engineered by fusing flaA promoter sequences gene encoding green fluorescent protein. When subjected depletion, accumulated ppGpp converted from...
Pathogenic Legionella pneumophila evolved as a parasite of aquatic amoebae. To persist in the environment, microbe must be proficient at both replication and transmission. In laboratory cultures, nutrients become scarce stringent response-like pathway coordinates exit from exponential growth phase with induction traits correlated virulence, including motility. A screen for mutants that express flagellin gene poorly identified five activators virulence: LetA/LetS, two-component regulator...
Using a process called quorum sensing (QS), bacteria communicate with extracellular signal molecules autoinducers (AIs). Response to AIs allows coordinate gene expression on population-wide scale and thereby carry out particular behaviors in unison, much like multicellular organisms. In Vibrio cholerae El Tor, the etiological agent of current cholera pandemic, AI information is transduced internally through phosphorelay circuit that impinges transcription multiple small regulatory RNAs...
Abstract By nature of their small size, dense growth and frequent need for extracellular metabolism, microbes face persistent public goods dilemmas. Genetic assortment is the only general solution stabilizing cooperation, but all known mechanisms structuring microbial populations depend on availability free space, an often unrealistic constraint. Here we describe a class self-organization that operates within densely packed bacterial populations. Through mathematical modelling experiments...
Significance Vibrio cholerae , the causative agent of diarrheal disease cholera, uses syringe-like type VI secretion system (T6SS) to pierce adjacent cells. To investigate role T6SS in invasion intestines already occupied by symbiotic microbes, we genetically engineered V. strains and performed live 3D imaging zebrafish find that can expel a resident bacterial species T6SS-dependent manner. Surprisingly, acts primarily increase strength gut contractions, rather than directly killing...
ABSTRACT Prior to the epidemic that emerged in Haiti October of 2010, cholera had not been documented this country. After its introduction, a strain Vibrio cholerae O1 spread rapidly throughout Haiti, where it caused over 600,000 cases disease and >7,500 deaths first two years epidemic. We applied whole-genome sequencing temporal series V. isolates from gain insight into mode tempo evolution isolated population O1. Phylogenetic Bayesian analyses supported hypothesis all sample set...
This article presents a branch of research where the use molecules to encode and transmit information among nanoscale devices (nanomachines) is investigated as bio-inspired viable solution realize nano-communication networks. Unlike traditional technologies, molecular communication radically new paradigm, which demands novel solutions, including identification naturally existing mechanisms, establishment foundations theory, or development architectures networking protocols for nanomachines....
Bacterial populations housed in microfluidic environments can serve as transceivers for molecular communication, but the data-rates are extremely low (e.g., 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-5</sup> bits per second.). In this work, genetically engineered Escherichia coli bacteria were maintained a device where their response to chemical stimulus was examined over time. The communication receiver simple modulation such on-off...
Predictive models are beneficial tools for researchers to use in prioritizing nanoparticles (NPs) toxicological tests, but experimental evaluation can be time-consuming and expensive, thus, priority should given tests that identify the NPs most likely harmful. For characterization of NPs, physical binding DNA molecules is important measure, as interference with function may one cause toxicity. Here, we determined interaction energy between 12 types based on Derjaguin-Landau-Verwey-Overbeek...
Vibrio cholerae, the causative agent of cholera and a natural inhabitant aquatic environments, regulates numerous behaviors using quorum-sensing (QS) system conserved among many members marine genus Vibrio. The QS response is mediated by two extracellular autoinducer (AI) molecules: CAI-I, which produced only Vibrios, AI-2, bacteria. In biofilms on chitinous surfaces, QS-proficient V. cholerae become naturally competent to take up DNA. Because direct role AIs in this environmental behavior...
Quorum sensing (QS), or cell-cell communication in bacteria, is achieved through the production and subsequent response to accumulation of extracellular signal molecules called autoinducers (AIs). To identify AI-regulated target genes Vibrio cholerae El Tor (V. cholerae(El)), strain responsible for current cholera pandemic, luciferase expression was assayed an AI(-) carrying a random lux transcriptional reporter library presence absence exogenously added AIs. Twenty-three were identified...
Vibrio cholerae quorum sensing controls expression of four redundant sRNAs, Qrr1-4. The Qrr sRNAs are predicted to alter the translation several mRNAs, including, hapR, which encodes a transcription factor that genes for virulence factors, biofilm formation, protease production and DNA uptake. Each contains 21 nucleotide region absolutely conserved among pathogenic Vibrios, base pair with mRNA targets, like aided by RNA chaperone Hfq. This molecular mechanism was not experimentally tested...
The facultative pathogen Vibrio cholerae transitions between its human host and aquatic reservoirs where it colonizes chitinous surfaces. Growth on chitin induces expression of utilization genes, genes involved in DNA uptake by natural transformation, a type VI secretion system that allows contact-dependent killing neighboring bacteria. We have previously shown the transcription factor CytR, thought to primarily regulate pyrimidine nucleoside scavenging response, is required for competence...
ABSTRACT Horizontal gene transfer (HGT) can have profound effects on bacterial evolution by allowing individuals to rapidly acquire adaptive traits that shape their strategies for competition. One strategy intermicrobial antagonism often used Proteobacteria is the genetically encoded contact-dependent type VI secretion system (T6SS), a weapon kill heteroclonal neighbors direct injection of toxic effectors. Here, we experimentally demonstrate Vibrio cholerae new T6SS effector genes via...
ABSTRACT The bacterial pathogen Vibrio cholerae can occupy both the human gut and aquatic reservoirs, where it may colonize chitinous surfaces that induce expression of factors for three phenotypes: chitin utilization, DNA uptake by natural transformation, contact-dependent killing via a type VI secretion system (T6SS). In this study, we surveyed diverse set 53 isolates from different geographic locales collected over past century clinical environmental specimens each phenotype outlined...
During the biofilm life cycle, bacteria attach to a surface and then reproduce, forming crowded, growing communities. Many theoretical models of growth dynamics have been proposed; however, difficulties in accurately measuring height across relevant time length scales prevented testing these models, or their biophysical underpinnings, empirically. Using white light interferometry, we measure heights microbial colonies with nanometer precision from inoculation final equilibrium height,...
Natural transformation is a major mechanism of horizontal gene transfer in bacteria. By incorporating exogenous DNA elements into chromosomes, bacteria are able to acquire new traits that can enhance their fitness different environments. Within the past decade, numerous studies have revealed natural prevalent among members Vibrionaceae, including pathogen Vibrio cholerae. Four environmental factors: (i) nutrient limitation, (ii) availability extracellular nucleosides, (iii) high cell density...
Like many bacteria, Vibrio cholerae deploys a harpoon-like type VI secretion system (T6SS) to compete against other microbes in environmental and host settings. The T6SS punctures adjacent cells delivers toxic effector proteins that are harmless bacteria carrying cognate immunity factors. Only four effector/immunity pairs encoded on one large three auxiliary gene clusters have been characterized from largely clonal, patient-derived strains of V. cholerae.We sequence two dozen strain genomes...
Summary Competence for genetic transformation in V ibrio cholerae is triggered by chitin‐induced transcription factor TfoX and quorum sensing ( QS ) regulator HapR . Transformation requires expression of ComEA , described as a DNA receptor other competent bacteria. A screen mutants that poorly expressed comEA –luciferase fusion identified cytR encoding the nucleoside scavenging cyt idine r epressor, previously shown to be biofilm repressor positively regulated but not linked Δ mutant was...
Summary Biofilms promote attachment of V ibrio cholerae in aquatic ecosystems and aid transmission. Intracellular c‐di‐ GMP levels that control biofilm development positively correlate with expression Q rr sRNAs , which are transcribed when quorum sensing ( QS ) autoinducer low. The base‐pair repress translation hapR encoding the ‘master regulator’, hence increased at low density were believed to be solely a consequence rr/ pairing. We show also activate mRNA diguanylate cyclase DGC ),...