The dynamic hypoosmotic response of relies on the mechanosensitive channel MscS.

adapts to osmotic down-shifts by releasing metabolites through two mechanosensitive (MS) channels, low-threshold MscS and high-threshold MscL. To investigate each channel's contribution to the osmotic response, we generated , , and double mutants in O395. We characterized their tension-dependent activation in patch-clamp, and the millisecond-scale osmolyte release kinetics using a stopped-flow light scattering technique.

The dynamic hypoosmotic response of Vibrio cholerae relies on the mechanosensitive channel MscS.

Like other intestinal bacteria, the facultative pathogen Vibrio cholerae adapts to a wide range of osmotic environments. Under drastic osmotic down-shifts, Vibrio avoids mechanical rupture by rapidly releasing excessive metabolites through mechanosensitive (MS) channels that belong to two major types, low-threshold MscS and high-threshold MscL. To investigate each channel individual contribution to V.

Chemical and genomic characterization of a potential probiotic treatment for stony coral tissue loss disease.

Considered one of the most devastating coral disease outbreaks in history, stony coral tissue loss disease (SCTLD) is currently spreading throughout Florida's coral reefs and the greater Caribbean. SCTLD affects at least two dozen different coral species and has been implicated in extensive losses of coral cover. Here we show Pseudoalteromonas sp.

Comparison of virulence in Pacific oyster larvae and corals.

The bacterium has been implicated in mass mortalities of corals and shellfish larvae. However, using corals for manipulative infection experiments can be logistically difficult compared to other model organisms, so we aimed to establish oyster larvae infections as a proxy model. Therefore, this study assessed the virulence of six wild-type strains, and mutants of one strain with deletions of known virulence factors, between Pacific oyster larvae () and Hawaiian rice coral () infection systems.

Disease Diagnostics and Potential Coinfections by During an Ongoing Coral Disease Outbreak in Florida.

A deadly coral disease outbreak has been devastating the Florida Reef Tract since 2014. This disease, stony coral tissue loss disease (SCTLD), affects at least 22 coral species causing the progressive destruction of tissue. The etiological agents responsible for SCTLD are unidentified, but pathogenic bacteria are suspected.

Comparative genomic analysis of Vibrios yields insights into genes associated with virulence towards C. gigas larvae.

Background: Vibriosis has been implicated in major losses of larvae at shellfish hatcheries. However, the species of Vibrio responsible for disease in aquaculture settings and their associated virulence genes are often variable or undefined. Knowledge of the specific nature of these factors is essential to developing a better understanding of the environmental and biological conditions that lead to larvae mortality events in hatcheries.

The aerobic respiratory chain of Pseudomonas aeruginosa cultured in artificial urine media: Role of NQR and terminal oxidases.

Pseudomonas aeruginosa is a Gram-negative γ-proteobacterium that forms part of the normal human microbiota and it is also an opportunistic pathogen, responsible for 30% of all nosocomial urinary tract infections. P. aeruginosa carries a highly branched respiratory chain that allows the colonization of many environments, such as the urinary tract, catheters and other medical devices.

Sodium antiporters of Pseudomonas aeruginosa in challenging conditions: effects on growth, biofilm formation, and swarming motility.

Background: Pseudomonas aeruginosa is a bacterial pathogen that can cause grave and sometimes chronic infections in patients with weakened immune systems and cystic fibrosis. It is expected that sodium/proton transporters in the cellular membrane are crucial for the organism's survival and growth under certain conditions, since many cellular processes rely on the maintenance of Na and H transmembrane gradients.

Results: This study focused on the role of the primary and secondary proton and/or sodium pumps Mrp, Nuo, NhaB, NhaP, and NQR for growth, biofilm formation, and swarming motility in P.

Insight into the resilience and susceptibility of marine bacteria to T6SS attack by Vibrio cholerae and Vibrio coralliilyticus.

The type VI secretion system (T6SS) is a nanomachine capable of killing adjacent microbial cells in a contact-dependent manner. Due to limited studies, relatively little is known about the range of marine bacteria that are susceptible to T6SS attack. Here, 15 diverse marine bacterial isolates from the phyla Bacteroidetes and Ɣ-Proteobacteria were challenged against the marine bacterium and human pathogen, Vibrio cholerae, which has a well described T6SS.

Impact of Na-Translocating NADH:Quinone Oxidoreductase on Iron Uptake and Expression in Vibrio cholerae.

The Na ion-translocating NADH:quinone oxidoreductase (NQR) from is a membrane-bound respiratory enzyme which harbors flavins and Fe-S clusters as redox centers. The NQR is the main producer of the sodium motive force (SMF) and drives energy-dissipating processes such as flagellar rotation, substrate uptake, ATP synthesis, and cation-proton antiport. The NQR requires for its maturation, in addition to the six structural genes , a flavin attachment gene, , and the gene, presumably encoding a Fe delivery protein.

Microbial Community Shifts Associated With the Ongoing Stony Coral Tissue Loss Disease Outbreak on the Florida Reef Tract.

As many as 22 of the 45 coral species on the Florida Reef Tract are currently affected by stony coral tissue loss disease (SCTLD). The ongoing disease outbreak was first observed in 2014 in Southeast Florida near Miami and as of early 2019 has been documented from the northernmost reaches of the reef tract in Martin County down to Key West. We examined the microbiota associated with disease lesions and apparently healthy tissue on diseased colonies of , , , and .

Metabolomics of Vibrio cholerae.

Metabolomics is an "omics" approach to quantitatively measure a large set of metabolites. In this chapter, we describe an example method for performing liquid chromatography coupled to mass spectrometry (LC-MS)-based untargeted metabolomics on a cell extract from Vibrio cholerae.

Factors affecting infection of corals and larval oysters by Vibrio coralliilyticus.

The bacterium Vibrio coralliilyticus can threaten vital reef ecosystems by causing disease in a variety of coral genera, and, for some strains, increases in virulence at elevated water temperatures. In addition, strains of V. coralliilyticus (formally identified as V.

Influence of Chemotaxis and Swimming Patterns on the Virulence of the Coral Pathogen Vibrio coralliilyticus.

Chemotaxis, the directed movement toward or away from a chemical signal, can be essential to bacterial pathogens for locating hosts or avoiding hostile environments. The coral pathogen chemotaxes toward coral mucus; however, chemotaxis has not been experimentally demonstrated to be important for virulence. To further examine this, in-frame mutations were constructed in genes predicted to be important for chemotaxis.

Environmental Controls of Oyster-Pathogenic Vibrio spp. in Oregon Estuaries and a Shellfish Hatchery.

spp. have been a persistent concern for coastal bivalve hatcheries, which are vulnerable to environmental pathogens in the seawater used for rearing larvae, yet the biogeochemical drivers of oyster-pathogenic spp. in their planktonic state are poorly understood.

Three Draft Genome Sequences of Strains Isolated from Bivalve Hatcheries.

Reported here are the genome sequences of three isolates RE87, AIC-7, and 080116A. Each strain was isolated in association with oyster larvae in commercial aquaculture systems. These draft genomes will be useful for further studies in understanding the genomic features contributing to pathogenicity.

Characterizing the Adherence Profiles of Virulent Vibrio parahaemolyticus Isolates.

The human pathogen Vibrio parahaemolyticus is a leading cause of seafood-borne illness in the USA, and infections with V. parahaemolyticus typically result from eating raw or undercooked oysters. V.

Chloroform-free permeabilization for improved detection of β-galactosidase activity in Vibrio cholerae.

LacZ (β-galactosidase) is used to monitor the transcription of genes in reporter strains carrying the lacZ gene under the control of a promotor of interest. This protocol for LacZ activity determinations in Vibrio cholerae following detergent lysis results in 2.5-fold increase of LacZ activities compared to lysis with chloroform.

Physiology of the Vc-NhaP paralogous group of cation-proton antiporters in Vibrio cholerae.

The genome of Vibrio cholerae encodes three cation-proton antiporters of NhaP-type, Vc-NhaP1, 2, and 3. To examine physiological roles of Vc-NhaP antiporters, triple ΔnhaP1ΔnhaP2ΔnhaP3 and single ΔnhaP3 deletion mutants of V. cholerae were constructed and characterized.

Effects of chromosomal deletion of the operon encoding the multiple resistance and pH-related antiporter in Vibrio cholerae.

To examine the possible physiological significance of Mrp, a multi-subunit cation/proton antiporter from Vibrio cholerae, a chromosomal deletion Δmrp of V. cholerae was constructed and characterized. The resulting mutant showed a consistent early growth defect in LB broth that became more evident at elevated pH of the growth medium and increasing Na+ or K+ loads.

The Na+-Translocating NADH:Quinone Oxidoreductase Enhances Oxidative Stress in the Cytoplasm of Vibrio cholerae.

Unlabelled: We searched for a source of reactive oxygen species (ROS) in the cytoplasm of the human pathogen Vibrio cholerae and addressed the mechanism of ROS formation using the dye 2',7'-dichlorofluorescein diacetate (DCFH-DA) in respiring cells. By comparing V. cholerae strains with or without active Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR), this respiratory sodium ion redox pump was identified as a producer of ROS in vivo The amount of cytoplasmic ROS detected in V.

Mortalities of Eastern and Pacific oyster Larvae caused by the pathogens Vibrio coralliilyticus and Vibrio tubiashii.

Vibrio tubiashii is reported to be a bacterial pathogen of larval Eastern oysters (Crassostrea virginica) and Pacific oysters (Crassostrea gigas) and has been associated with major hatchery crashes, causing shortages in seed oysters for commercial shellfish producers. Another bacterium, Vibrio coralliilyticus, a well-known coral pathogen, has recently been shown to elicit mortality in fish and shellfish. Several strains of V.

Roles of the sodium-translocating NADH:quinone oxidoreductase (Na+-NQR) on vibrio cholerae metabolism, motility and osmotic stress resistance.

The Na+ translocating NADH:quinone oxidoreductase (Na+-NQR) is a unique respiratory enzyme catalyzing the electron transfer from NADH to quinone coupled with the translocation of sodium ions across the membrane. Typically, Vibrio spp., including Vibrio cholerae, have this enzyme but lack the proton-pumping NADH:ubiquinone oxidoreductase (Complex I).

Autolysis in Vibrio tubiashii and Vibrio coralliilyticus.

Vibrio tubiashii has been linked to disease outbreaks in molluscan species, including oysters, geoducks, and clams, and shellfish hatcheries in the Pacific Northwest have been plagued by intermittent vibriosis outbreaks since 2006. Like V. tubiashii, Vibrio coralliilyticus has recently been described as an oyster pathogen in addition to its role in coral disease.

Inhibition of the sodium-translocating NADH-ubiquinone oxidoreductase [Na+-NQR] decreases cholera toxin production in Vibrio cholerae O1 at the late exponential growth phase.

Two virulence factors produced by Vibrio cholerae, cholera toxin (CT) and toxin-corregulated pilus (TCP), are indispensable for cholera infection. ToxT is the central regulatory protein involved in activation of CT and TCP expression. We previously reported that lack of a respiration-linked sodium-translocating NADH-ubiquinone oxidoreductase (Na(+)-NQR) significantly increases toxT transcription.