Abrin Toxin Paradoxically Increases Protein Synthesis in Stimulated CD4 T-Cells While Decreasing Protein Synthesis in Kidney Cells.

Abrin, a toxin of the rosary pea plant (), has been implicated as causing an autoimmune demyelinating disease in humans, but the exact mechanisms responsible for the induction of these demyelinating conditions are still unknown. Certain superantigen microbial toxins such as Staphylococcus enterotoxin type A, type D, type E or streptococcal pyrogenic exotoxin type C also lead to various diseases including autoimmune disorders of the nervous system. Here, the effect of abrin toxin on the immune reaction was studied in human CD4 T-cell lines, and its inhibition of protein synthesis in kidney cells.

Streptococcal pyrogenic exotoxin B is a superantigen that induces murine splenocyte proliferation and secretion of IL-2 and IFN-γ ex vivo.

Streptococcus pyogenes is a significant human pathogen, producing a range of virulence factors, including streptococcal pyrogenic exotoxin B (SpeB) that is associated with foodborne outbreaks. It was only known that this cysteine protease mediates cleavage of transmembrane proteins to permit bacterial penetration and is found in 25% of clinical isolates from streptococcal toxic shock syndrome patients with extreme inflammation. Its interaction with host and streptococcal proteins has been well characterized, but doubt remains about whether it constitutes a superantigen.

A Sensitive, Cell-Based Assay for Measuring Low-Level Biological Activity of α-Amanitin.

α-Amanitin is one of the primary toxins produced by the poisonous mushroom genus, . Because it is odorless and tasteless, it is an important cause of death from the consumption of misidentified mushrooms. To study the thermal stability of α-amanitin, novel cell-based assays were developed to measure the toxin's activity, based on the inhibition of RNA polymerase II by α-amanitin.

Development of Thermally Stable Nanobodies for Detection and Neutralization of Staphylococcal Enterotoxin B.

In this study, sixteen unique staphylococcal enterotoxin B (SEB)-reactive nanobodies (nbs), including ten monovalent and six bivalent nbs, were developed. All characterized nbs were highly specific for SEB and did not cross-react with other staphylococcal enterotoxins (SE). Several formats of highly sensitive enzyme-linked immunosorbent assays (ELISAs) were established using SEB nbs and a polyclonal antibody (pAb).

T-cell receptor Vβ8 for detection of biologically active streptococcal pyrogenic exotoxin type C.

Streptococcus pyogenes is an important human pathogen, commonly spread by airborne droplets but also by ingestion of contaminated food. Apart from causing infection, this pathogen produces 13 distinct types of streptococcal pyrogenic exotoxins (SPE). The current method for detection cannot distinguish between the biologically active form of SPE that has been reported to cause foodborne outbreaks and the inactivated toxin that poses no health risk.

Effect of an Eco-Friendly Cuminaldehyde Guanylhydrazone Disinfectant on Shiga Toxin Production and Global Transcription of .

Antimicrobials have been important medicines used to treat various infections. However, some antibiotics increase the expression of Shiga toxin (Stx). Also, the pervasive use of persistent antibiotics has led to ecotoxicity and antibiotic resistance.

Evaluation of a Witch Hazel Extract for the Potential Prebiotic and Protective Effect on Select (Prev. ) Strains.

Witch hazel extract has been evaluated in prior studies demonstrating the phenolic-mediated biofilm inhibition, toxin production inhibition, and growth inhibition in . In this study, we are evaluating the possible prebiotic and protective effect of witch hazel extract on select probiotic strains, namely LP 10241 and LPBAA-793. When the prebiotic effect was evaluated, we observed that the tested extract had prebiotic effect at the higher tested dose (0.

The Effect of Tannin-Rich Witch Hazel on Growth of Probiotic .

Probiotic bacteria help maintain microbiome homeostasis and promote gut health. Maintaining the competitive advantage of the probiotics over pathogenic bacteria is a challenge, as they are part of the gut microbiome that is continuously exposed to digestive and nutritional changes and various stressors. Witch hazel that is rich in hamamelitannin (WH, whISOBAX) is an inhibitor of growth and virulence of pathogenic bacteria.

Ex Vivo and In Vitro Methods for Detection of Bioactive Staphylococcal Enterotoxins.

Staphylococcus aureus is a major bacterial cause of clinical infections and foodborne illnesses.Through the synthesis of a group of Staphylococcal enterotoxins (SEs), gastroenteritis occurs and the SEs function as superantigens to massively activate T cells. The ability to rapidly detect and quantify SEs is imperative in order to learn the causes of staphylococcal outbreaks and to stop similar outbreaks in the future.

Prevalence and Genetic Analysis of Chromosomal in From U.S. Animal-Derived Samples.

The prevalence of -positive bacteria in 5,169 domestic animal-derived samples collected by USDA Food Safety and Inspection Service between October 2018 and May 2019 was investigated. A procedure including enriched broth culture and real-time PCR targeting to were used for the screening. Fifteen positive isolates were identified, including one plasmid-borne -positive strain, EC2492 (reported elsewhere) and 14 -positive strains from poultry (1), catfish (2), and chicken rinse (11) samples, resulting in an overall prevalence of -positive bacteria 0.

Human Leukemia T-Cell Lines as Alternatives to Animal Use for Detecting Biologically Active Staphylococcal Enterotoxin Type B.

Staphylococcal enterotoxin type B (SEB) is associated with food poisoning. Current methods for the detection of biologically active SEB rely upon its ability to cause emesis when administered to live kittens or monkeys. This technique suffers from poor reproducibility and low sensitivity and is ethically disfavored over concerns for the welfare of laboratory animals.

Validation of a Cell-Based Assay for Detection of Active Shiga Toxins Produced by in Water.

Shiga toxin-producing (STEC) causes a wide spectrum of diseases, including hemorrhagic colitis and hemolytic uremic syndrome (HUS). Almost 5% of STEC infections result from waterborne exposures, yet there is no test listed in the EPA's current Selected Analytical Methods for the detection of active Shiga toxins (Stxs) in water. In this study, a HeLa cell-based assay is validated for the detection of metabolically active Stxs produced by STEC in water, including tap, bottled, and pond water.

Quantitative bioluminescence assay for measuring Bacillus cereus nonhemolytic enterotoxin complex.

Bacillus cereus is a foodborne pathogen causing emesis and diarrhea in those affected. It is assumed that the non-hemolytic enterotoxin (Nhe) plays a key role in B. cereus induced diarrhea.

whISOBAX Inhibits Bacterial Pathogenesis and Enhances the Effect of Antibiotics.

As bacteria are becoming more resistant to commonly used antibiotics, alternative therapies are being sought. whISOBAX (WH) is a witch hazel extract that is highly stable (tested up to 2 months in 37 °C) and contains a high phenolic content, where 75% of it is hamamelitannin and traces of gallic acid. Phenolic compounds like gallic acid are known to inhibit bacterial growth, while hamamelitannin is known to inhibit staphylococcal pathogenesis (biofilm formation and toxin production).

CCD Based Detector for Detection of Abrin Toxin Activity.

Abrin is a highly potent and naturally occurring toxin produced in the seeds of (Rosary Pea) and is of concern as a potential bioterrorism weapon. There are many rapid and specific assay methods to detect this toxic plant protein, but few are based on detection of toxin activity, critical to discern biologically active toxin that disables ribosomes and thereby inhibits protein synthesis, producing cytotoxic effects in multiple organ systems, from degraded or inactivated toxin which is not a threat. A simple and low-cost CCD detector system was evaluated with colorimetric and fluorometric cell-based assays for abrin activity; in the first instance measuring the abrin suppression of mitochondrial dehydrogenase in Vero cells by the MTT-formazan method and in the second instance measuring the abrin suppression of green fluorescent protein (GFP) expression in transduced Vero and HeLa cells.

Witch Hazel Significantly Improves the Efficacy of Commercially Available Teat Dips.

Bovine intramammary infections (IMIs) are the main cause of economic loss in milk production. Antibiotics are often ineffective in treating infections due to antimicrobial resistance and the formation of bacterial biofilms that enhance bacterial survival and persistence. Teat dips containing germicides are recommended to prevent new IMIs and improve udder health and milk quality.

Inhibition of Staphylococcal Pathogenesis by Witch-Hazel and Green Tea Extracts.

whISOBAX (WH), an extract of the witch-hazel plant that is native to the Northeast coast of the United States, contains significant amounts of a phenolic compound, Hamamelitannin (HAMA). Green tea (GT) is a widely consumed plant that contains various catechins. Both plants have been associated with antimicrobial effects.

T cell Receptor Vβ9 in Method for Rapidly Quantifying Active Staphylococcal Enterotoxin Type-A without Live Animals.

Staphylococcal food poisoning is a result of ingestion of Staphylococcal enterotoxins (SEs) produced by . Staphylococcal enterotoxin type A (SEA) is the predominant toxin produced by strains isolated from food-poisoning outbreak cases. For public safety, assays to detect and quantify SEA ideally respond only to the active form of the toxin and this usually means employing disfavored live animal testing which suffers also from poor reproducibility and sensitivity.

Alternative to Animal Use for Detecting Biologically Active Staphylococcal Enterotoxin Type A.

Staphylococcal enterotoxins (SEs) are a food safety concern. Existing methods for biologically active SE detection rely on the emetic response in live kittens or monkeys. This method suffers from low sensitivity, poor reproducibility, and causes ethical concerns regarding the use of experimental animals.

Synthesis of pyrrolidine-based hamamelitannin analogues as quorum sensing inhibitors in .

Interfering with bacterial cell-to-cell communication is a promising strategy to combat antimicrobial resistance. The natural product hamamelitannin and several of its analogues have been identified as quorum sensing inhibitors. In this paper the synthesis of pyrrolidine-based analogues of a more lead-like hamamelitannin analogue is reported.

Detection of Abrin Holotoxin Using Novel Monoclonal Antibodies.

Abrin, a member of the ribosome-inactivating protein family, is produced by the plant. Having the potential to pose a severe threat to both human and animal health, abrin is classified as a Select Agent by the U.S.

Interleukin 2 Secretion by T Cells for Detection of Biologically Active Staphylococcal Enterotoxin Type E.

Staphylococcus aureus is a significant worldwide source of clinical infections and foodborne illnesses; it acts through the synthesis of a group of enterotoxins (SEs) that cause gastroenteritis and also function as superantigens that activate T cells, resulting in massive cytokine production, yielding life-threatening toxicity. It is important that methods for detection and quantification of these toxins respond to their activity and not just the presence of the toxin molecule, which may be deactivated. Traditionally, live animals have been used to test for emesis following administration of the toxin-containing sample.

Novel monoclonal antibodies against Stx1d and 1e and their use for improving immunoassays.

Shiga toxins (Stxs) are major causative agents for bloody diarrhea and hemolytic uremic syndrome, a life-threatening disease in humans. No effective treatment is available. Early detection of Stxs in clinical samples is critical for disease management.

Low-Cost Charged-Coupled Device (CCD) Based Detectors for Shiga Toxins Activity Analysis.

To improve food safety there is a need to develop simple, low-cost sensitive devices for detection of food-borne pathogens and their toxins. We describe a simple, low-cost webcam-based detector which can be used for various optical detection modalities, including fluorescence, chemiluminescence, densitometry, and colorimetric assays. The portable battery-operated CCD-based detection system consists of four modules: (1) a webcam to measure and record light emission, (2) a sample plate to perform assays, (3) a light emitting diode (LED) for illumination, and (4) a portable computer to acquire and analyze images.

Rapid Cell-Based Assay for Detection and Quantification of Active Staphylococcal Enterotoxin Type D.

Food poisoning by Staphylococcus aureus is a result of ingestion of Staphylococcal enterotoxins (SEs) produced by this bacterium and is a major source of foodborne illness. Staphylococcal enterotoxin D (SED) is one of the predominant enterotoxins recovered in Staphylococcal food poisoning incidences, including a recent outbreak in Guam affecting 300 children. Current immunology methods for SED detection cannot distinguish between the biologically active form of the toxin, which poses a threat, from the inactive form, which poses no threat.