Clostridium difficile is the major cause of antibiotic-associated colitis, a disease with significant morbidity and mortality. This study investigated the role of the haem oxygenase-1 (HO-1)/carbon monoxide (CO) pathway in C. difficile toxin A-induced enteritis in mice. The HO substrate haemin, zinc protoporphyrin IX (ZnPP IX), a specific HO-1 inhibitor, dimanganese decacarbonyl (DMDC), a CO do...

Lipophilic phycotoxins are secondary metabolites produced by phytoplanktonic species. They accumulate in filter-feeding shellfish and can cause human intoxication. Regulatory limits have been set for individual toxins, and the toxicological features are well characterized for some of them. However, phycotoxin contamination is often a co-exposure phenomenon, and toxicological data regarding mixt...

BACKGROUND Animal neurotoxin peptides are valuable probes for investigating ion channel structure/function relationships and represent lead compounds for novel therapeutics and insecticides. However, misfolding and aggregation are common outcomes when toxins containing multiple disulfides are expressed in bacteria. METHODS The β-scorpion peptide toxin Bj-xtrIT from Hottentotta judaica and fou...

The structures of the toxins produced by Cochliobolus victoriae, victorin B, C, D, E, and victoricine, have recently been established. These toxins and modified forms of victorin C were tested for their effect on dark CO(2) fixation in susceptible oat (Avena sativa) leaf slices. Half-maximal inhibition of dark CO(2) fixation occurred with the native toxins in the range of 0.004 to 0.546 micromo...

Long-term, recombinant gene expression in mammalian cells depends on the nature of the transgene integration site and its inherent properties to modulate transcription (epigenetic effects). Here we describe a method by which high transgene expression is achieved and stabilized in extensively proliferating cultures. The method is based on strict co-expression of the transgene with an antitoxin i...

BACKGROUND Although useful for probing bacterial pathogenesis and physiology, current random mutagenesis systems suffer limitations for studying the toxin-producing bacterium Clostridium perfringens. METHODOLOGY/PRINCIPAL FINDINGS An EZ-Tn5-based random mutagenesis approach was developed for use in C. perfringens. This mutagenesis system identified a new regulatory locus controlling toxin pro...

Much of the knowledge we have about regulation of transcription in prokaryotes comes from two particularly well-studied systems: the Lac repressor-lac operon [1] and the λ-repressor and λ-Cro for the control of the lysogenic/lytic cycles of λ-phage [2]. In both cases, the repressors are well-folded species lacking appreciable structural disorder. Eukaryotic transcription factors on the other ha...

LC-MSn analysis of mycolactone toxin from extracts of Mycobacterium ulcerans has shown that minor co-metabolites, including two previously unreported, differ structurally from mycolactone only in a small portion of the polyketide side-chain.

Certain protein toxins, including cholera toxin, ricin, and Pseudomonas aeruginosa exotoxin A, are transported to the lumen of the endoplasmic reticulum where they retro-translocate across the endoplasmic reticulum membrane to enter the cytoplasm. The mechanism of retrotranslocation is poorly understood but may involve the endoplasmic reticulum-associated degradation pathway. The AAA ATPase p97...

Paralytic shellfish toxins (PSTs), a group of neurotoxic alkaloids, are the most potent biotoxins for aquatic ecosystems and human health. Marine dinoflagellates and freshwater cyanobacteria are two producers of PSTs. The biosynthesis mechanism of PSTs has been well elucidated in cyanobacteria; however, it remains ambiguous in dinoflagellates. Here, we compared the transcriptome profiles of a t...