Vibrio parahaemolyticus is a Gram-negative, halophilic, human pathogenic bacterium ubiquitous in the marine environment. Like many Vibrio species, V. parahaemolyticus commonly associates with shellfish, particularly oysters. Ingestion of a raw or under cooked oysters contaminated with V. parahaemolyticus can cause gastroenteritis, which is typically self-limiting and rarely causes death. Globally,...
The pathogen Vibrio cholerae uses cations as a primary currency of virulence
and environmental persistence, using gradients of those cations to move, acquire
nutrients, and control virulence gene expression. An understanding of the overlapping
roles of bioenergetics and chemotaxis in the virulence and environmental survival of
V. cholerae issues from...
The purpose of this project is to study which methyl-accepting chemotaxis proteins (MCPs) are related to chemotaxis of Vibrio cholerae. 44 MCP mutant strains were tested in seven different chemoattractants and the resulting swarm circle size was compared to that of C6706 lac-Z wildtype. Several genes were identified that resulted...
We found that a strains of Yersinia pestis (KIM5) which lacked the nhaA gene was fully attenuated in a plague model. This gene produces a protein of the sodium-proton antiporter family which expel sodium ions from the bacterial cytoplasm in exchange for hydrogen ions, or protons, from the surrounding environment....
Vibrio cholerae is the causative agent of cholera, a serious diarrheal disease in developing countries. V. cholerae has a unique redox driven respiration-linked sodium pump, Na⁺ translocating NADH:quinone oxidoreductase (NQR). Several reports previously showed that NQR plays an important role in virulence, metabolism, and sodium homeostasis of V. cholerae. This...
Haemonchus sp. is known to be present in geographical regions of Oregon that are more arid and warm, which has been the preferred climate of this parasite. However, it was not detected in Western Oregon bovine until recently. Haemonchus sp. was first detected in Western Oregon bovine from a fecal...
The ability to move towards favorable environmental conditions, called chemotaxis, is common among motile bacteria. In particular aerotaxis has been extensively studied in Escherichia coli. Three putative aer gene homologs were identified in the V. cholerae genome designated VCAer-1 (VC0512) VCAer-2 (VCA0658), and VCAer-3 (VCA0988). Deletion analyses indicated that only...
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 suspected that specialized sodium pumps in the cellular membrane are crucial for the organism’s survival and growth, since many cellular processes rely on the maintenance...
Vibrio cholerae (Vc), the etiological agent of cholera, has developed many mechanisms to combat the great fluctuations in pH, ion content and osmotic conditions of the vastly differing environments it encounters through its infections of the human host. A series of cation antiporters are found in the Vc membrane to...
Vibrio parahaemolyticus, a naturally occurring halophilic pathogen, is seasonally abundant in marine and estuarine environments. It is also the leading cause of gastroenteritis in humans world-wide. Numerous outbreak incidences associated with the pathogenic Vibrio parahaemolyticus contaminations in oyster products have raised public-health concerns as well as economic challenges to the...
Vibrio cholerae is a gram-negative gammaproteobacteria, well
known for causing the watery-diarrheal disease Cholera. V. cholerae is
endemic to the marine and freshwater ecosystems of India and
surrounding aquatic environments within that region. Primary
reservoirs include brackish water and estuaries. The primary symptom
is rapid dehydration due to watery diarrhea....
Mycobacterium avium is a ubiquitous environmental organism found in water and soil. It can cause disease in patients with pre-existing pulmonary conditions, immunocompromised patients with the most prevalent being AIDS patients, as well as apparently healthy people. Studies have indicated that, upon macrophage uptake, Al. avium prevents phagosome-lysosome fusion, thus...
Vibrio coralliilyticus (Vcor) is a bacterial pathogen that is well adapted to shellfish hatcheries and is very pathogenic to the larvae of the Pacific oyster Crassostrea gigas. Vcor has been associated with several large scale larval mortality events in the Pacific Northwest that interrupt the supply of seed oysters available...
Mycobacterium avium subsp. hominissuis (MAH) belongs to the most-clinically significant non-tuberculous mycobacterial (NTM) pathogens with constant increase in disease prevalence, mainly in several industrialized western countries where tuberculosis is less prevalent. Upon entry into the alveolar space, MAH is engulfed by resident-macrophages, where the pathogen adapts to the hostile phagosomal...
Vibrio tubiashii has been linked to disease outbreaks in molluscan species, including oysters, geoducks, and clams. In particular, oyster hatcheries in the Pacific Northwest have been plagued by intermittent vibriosis since 2006. Accurate detection of vibrios, including V. tubiashii, is critical to the hatcheries in order to allow for rapid...
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. In...
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., Fassio, S. R., Reddekopp, R. L., & Häse, C. C. (2014). Inhibition of the
sodium-translocating NADH
We previously found that inhibition of the TCA cycle, either through mutations or chemical inhibition, increased toxT transcription in Vibrio cholerae. In this study, we found that the addition of malonate, an inhibitor of succinate dehydrogenase (SDH), decreased toxT transcription in V. cholerae, an observation inconsistent with the previous pattern...
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. In...
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. In...
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. In...
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. In...
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. In...
C. perfringens type A isolates are the causative agents of C. perfringens type A food poisoning (FP) and non-food-borne (NFB) human gastrointestinal diseases. In this study, we evaluated the antimicrobial effect of essential oil constituents (cinnamaldehyde, eugenol, allyl isothiocyanate (AITC), and carvacrol) against C. perfringens FP and NFB isolates grown...
Clostridium perfringens is a spore-forming pathogenic bacterium that causes a variety of diseases in human and animals. C. perfringens type A isolates produce enterotoxin (CPE) causing food poisoning (FP) and non-food-borne (NFB) gastrointestinal (GI) diseases including antibiotic-associated diarrhea and sporadic diarrhea. C. perfringens type A food poisoning currently ranks as...
Vibrio bacteria are commonly found in freshwater, marine, and estuarine environments. Members of this genus can exist in commensal relationships with marine animals or as planktonic bacteria, however, they are well known for their roles as pathogens towards humans and animals. In this dissertation, I investigated aspects of host-bacteria relationships...
Vibrio parahaemolyticus is frequently isolated or detected from raw seafoods, especially shellfish. Also, Listeria monocytogenes, Salmonella spp. are pathogens that are frequently found in ready-to-eat (RTE) seafood, such as smoked fish and shellfish, seafood salad, cooked shrimp and crabmeat, and seafood consumed raw. Two studies to improve safety in RTE...
Vibrio parahaemolyticus infections in the United Stated have been linked to consumption of raw shellfish, particularly oysters, with symptoms of headache, abdominal pain, nausea, diarrhea, vomiting. Depuration, as a post-harvest process, has a long history of being applied in shellfish industry to reduce sewage bacteria. In order to reduce the...
Nisin, an amphiphilic, antimicrobial peptide, has been shown to integrate into the hydrophobic inner region of poly(ethylene oxide) (PEO) brush layers; however, the presence of integrated nisin may compromise the protein repulsive character of the PEO layer. In particular, the introduction of fibrinogen to nisin-loaded brush layers has been observed...
A low, but significant, fraction of the carbohydrate portion of herbaceous biomass may be composed of fructose/fructosyl-containing components (“fructose equivalents”); such carbohydrates include sucrose, fructo-oligosaccharides, and fructans. Standard methods used for the quantification of structural-carbohydrate-derived neutral monosaccharide-equivalents in biomass are not particularly well suited for the quantification of fructose equivalents...
Curbing overall disease burden with faster intervention requires early stage and accurate diagnostics. Ultrasound (US) provides a safe, nonionizing, inexpensive, and noninvasive imaging modality that has become commonplace in diagnostics. Paired with the relatively new technology of photoacoustic imaging (PAI), optical level resolution becomes feasible with the deeper signal penetration...
OmniGen-AF® (OG; Prince Agri Products, Inc., Quincy, IL) is a feed additive containing brewers dehydrated yeast and B-vitamins that supports immune function in ruminant livestock. Targeted profiling of immune-associated genes in whole blood is an effective platform for identification of a) novel molecular pathways and b) immune response markers to...
Light Detection and Ranging (LIDAR) is a powerful resource for coastal and wetland managers and its use is increasing. Vegetation density and other land cover characteristics influence the accuracy of LIDAR-derived ground surface digital elevation models; however, the degree to which wetland land cover biases LIDAR estimates of the ground...
Francisella tularensis is a gram-negative facultative intracellular
coccobacillus that primarily infects macrophages. The causative agent of tularemia,
this bacterium is considered among the most infectious organisms known, requiring
fewer than ten organisms to cause disease. Although ubiquitous in nature,
transmission to humans is rare but can occur via insect bites,...
Alaska pollock (Gadus chalcogrammus) is a schooling whitefish native to the Bering Sea that is prized for its fillets, surimi, roe, and milt. Fillets are frequently used for popular products such as fish and chips. If collected, roe and milt are commonly exported to South Korea and Japan. However, no...
We previously reported that inhibition of the Na⁺ translocating NADH:ubiquinone oxidoreductase (NQR), either by chemical inhibition or mutation, increased toxT transcription in Vibrio cholerae. In this study, we revealed that the nqr mutant strain showed similar phenotypes as the Escherichia coli NADH dehydrogenase I (nuo) mutant strain (e.g. growth defect...
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. Nature 406:477-483.
2. Häse, C. C., and J. J. Mekalanos. 1999. Effects of changes in membrane sodium flux
We previously reported that inhibition of the Na⁺ translocating NADH:ubiquinone oxidoreductase (NQR), either by chemical inhibition or mutation, increased toxT transcription in Vibrio cholerae. In this study, we revealed that the nqr mutant strain showed similar phenotypes as the Escherichia coli NADH dehydrogenase I (nuo) mutant strain (e.g. growth defect...
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both chromosomes of the cholera pathogen Vibrio cholerae. Nature 406:477-483.
2. Häse, C. C., and J
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...
We previously reported that inhibition of the Na⁺ translocating NADH:ubiquinone oxidoreductase (NQR), either by chemical inhibition or mutation, increased toxT transcription in Vibrio cholerae. In this study, we revealed that the nqr mutant strain showed similar phenotypes as the Escherichia coli NADH dehydrogenase I (nuo) mutant strain (e.g. growth defect...
Clostridium perfringens type A isolates, an anaerobic enterotoxigenic spore forming bacterium, are the third leading cause of food-borne disease in the United States. Factors that contribute to the virulence of C. perfringens include the ability of the bacterium to form heat resistant spores and to produce an enterotoxin (CPE). Although...
Woodturner, artist, and scientist, Claudia Andersen, describes various anatomical features of wood, from the differences between softwoods and hardwoods to the various types of spalting. Over the past year, they have learned and developed their skills in woodturning. In this project, they accompany one woodturned piece with a description of...
Clostridium perfringens is a Gram-positive, anaerobic, spore-forming bacterium that can produce as many as 17 different toxins and are responsible to cause a wide array of gastrointestinal (GI) and histotoxic diseases in humans and animals. As individual strains produce a subset of these toxins, C. perfringens strains can be classified...
C. perfringens is a spore-forming, gram-positive, anaerobic pathogenic bacterium capable of causing a wide variety of diseases in both humans and animals. However, the two most common illnesses in humans are C. perfringens type A food poisoning (FP) and non-food-borne (NFB) gastrointestinal (GI) illnesses. Interestingly, these two major diseases are...
Vibrio parahaemolyticus is a leading cause of acute gastroenteritis associated with consumption of seafood, particularly raw oysters. The United States Centers for Disease Control and Prevention (CDC) estimated that 45,000 cases of V. parahaemolyticus infection occur each year in the U.S. A recent CDC report revealed that the incidence of...
Carboxylic acids have played an important role in the field of actinide (An) and lanthanide (Ln) separations and the reprocessing of irradiated nuclear fuel. Recent bench-scale experiments have demonstrated that 3-carboxy-3-hydroxypentanedioic acid (citric acid) is a promising aqueous complexant that can effectively aid in the separation of transition metals from...
Pseudomonas aeruginosa is an opportunistic human pathogen that infects immunocompromised individuals such as those suffering from burns or the genetic disorder cystic fibrosis. This organism utilizes a cell-cell communication mechanism known as quorum sensing (QS) to coordinate virulence gene expression and biofilm formation. It has three interconnected QS systems, namely...
Vibrio cholerae has adapted to a wide range of salinity, pH and osmotic conditions, enabling it to survive passage through the host and persist in the environment. Among the many proteins responsible for bacterial survival under these diverse conditions, we have identified Vc-NhaP1 as a K+(Na+)/H+ antiporter essential for V....
Marine bacteria play vital roles in every niche of the ocean, from small-scale symbioses to large-scale productivity and the regulation of Earth’s climate. Recent advances in molecular tools now allow us to probe the genetic potential of entire microbial communities. The next step is linking these diverse communities to the...
Phospholipase C-β (PLC-β) isozymes are key effectors in G protein-coupled
signaling pathways. Prior research suggested that some isoforms of PLC-β may exist
and function as dimers, but little is known about dimerization of PLC-β. Data from coimmunoprecipitation
assays of differentially-tagged PLC-β constructs and sizeexclusion
chromatography of native PLC-β support homodimerization...
Mass Spectrometry has emerged as an analytical core technique in omics sciences, in particularly mass spectrometry has advanced the fields of proteomics, metabolomics and lipidomics in recent years. Mass spectrometric techniques have enabled the characterization and determination of abundance levels of a wide range of biomolecules at molecular and system-wide...
Oxidative stress is defined as an imbalance that favors the production of reactive oxygen species (ROS) over an organism's antioxidant defense. ROS have the ability to damage, either directly or indirectly, biomolecules including DNA, proteins, carbohydrates, and lipids. Various pathological conditions and environmental and chronic diseases have been associated with...