Bongkrekic Acid-a Review of a Lesser-Known Mitochondrial Toxin.

INTRODUCTION: Bongkrekic acid (BA) has a unique mechanism of toxicity among the mitochondrial toxins: it inhibits adenine nucleotide translocase (ANT) rather than the electron transport chain. Bongkrekic acid is produced by the bacterium Burkholderia gladioli pathovar cocovenenans (B. cocovenenans) which has been implicated in outbreaks of food-borne illness involving coconut- and corn-based products in Indonesia and China. Our objective was to summarize what is known about the epidemiology, exposure sources, toxicokinetics, pathophysiology, clinical presentation, and diagnosis and treatment of human BA poisoning. METHODS: We searched MEDLINE (1946 to present), EMBASE (1947 to present), SCOPUS, The Indonesia Publication Index ( http://id.portalgaruda.org/ ), ToxNet, book chapters, Google searches, Pro-MED alerts, and references from previously published journal articles. We identified a total of 109 references which were reviewed. Of those, 29 (26 %) had relevant information and were included. Bongkrekic acid is a heat-stable, highly unsaturated tricarboxylic fatty acid with a molecular weight of 486 kDa. Outbreaks have been reported from Indonesia, China, and more recently in Mozambique. Very little is known about the toxicokinetics of BA. Bongkrekic acid produces its toxic effects by inhibiting mitochondrial (ANT). ANT can also alter cellular apoptosis. Signs and symptoms in humans are similar to the clinical findings from other mitochondrial poisons, but they vary in severity and time course. Management of patients is symptomatic and supportive. CONCLUSIONS: Bongkrekic acid is a mitochondrial ANT toxin and is reported primarily in outbreaks of food-borne poisoning involving coconut and corn. It should be considered in outbreaks of food-borne illness when signs and symptoms manifest involving the liver, brain, and kidneys and when coconut- or corn-based foods are implicated.

Laboratory Prototype of Bioreactor for Oxidation of Toxic D-Lactate Using Yeast Cells Overproducing D-Lactate Cytochrome c Oxidoreductase.

D-lactate is a natural component of many fermented foods like yogurts, sour milk, cheeses, and pickles vegetable products. D-lactate in high concentrations is toxic for children and people with short bowel syndrome and provokes encephalopathy. These facts convincingly demonstrate a need for effective tools for the D-lactate removal from some food products. The main idea of investigation is focused on application of recombinant thermotolerant methylotrophic yeast Hansenula polymorpha "tr6," overproducing D-lactate: cytochrome c oxidoreductase (EC 1.1.2.4, D-lactate cytochrome c oxidoreductase, D-lactate dehydrogenase (cytochrome), DLDH). In addition to 6-fold overexpression of DLDH under a strong constitutive promoter (prAOX), the strain of H. polymorpha "tr6" (gcr1 catX/Δcyb2, prAOX_DLDH) is characterized by impairment in glucose repression of AOX promoter, devoid of catalase and L-lactate-cytochrome c oxidoreductase activities. Overexpression of DLDH coupling with the deletion of L-lactate-cytochrome c oxidoreductase activity opens possibility for usage of the strain as a base for construction of bioreactor for removing D-lactate from fermented products due to oxidation to nontoxic pyruvate. A laboratory prototype of column-type bioreactor for removing a toxic D-lactate from model solution based on permeabilized cells of the H. polymorpha "tr6" and alginate gel was constructed and efficiency of this process was tested.

The structure of Clostridium perfringens NanI sialidase and its catalytic intermediates.

Clostridium perfringens is a Gram-positive bacterium responsible for bacteremia, gas gangrene, and occasionally food poisoning. Its genome encodes three sialidases, nanH, nanI, and nanJ, that are involved in the removal of sialic acids from a variety of glycoconjugates and that play a role in bacterial nutrition and pathogenesis. Recent studies on trypanosomal (trans-) sialidases have suggested that catalysis in all sialidases may proceed via a covalent intermediate similar to that of other retaining glycosidases. Here we provide further evidence to support this suggestion by reporting the 0.97A resolution atomic structure of the catalytic domain of the C. perfringens NanI sialidase, and complexes with its substrate sialic acid (N-acetylneuramic acid) also to 0.97A resolution, with a transition-state analogue (2-deoxy-2,3-dehydro-N-acetylneuraminic acid) to 1.5A resolution, and with a covalent intermediate formed using a fluorinated sialic acid analogue to 1.2A resolution. Together, these structures provide high resolution snapshots along the catalytic pathway. The crystal structures suggested that NanI is able to hydrate 2-deoxy-2,3-dehydro-N-acetylneuraminic acid to N-acetylneuramic acid. This was confirmed by NMR, and a mechanism for this activity is suggested.

Development of a protein phosphatase-based assay for the detection of phosphatase inhibitors in crude whole cell and animal extracts.

Diarrhetic shellfish poisoning (DSP) is a serious and globally widespread phytoplankton-related seafood illness. Although DSP is rarely life-threatening, it causes incapacitating diarrhea and vomiting with no known medical treatments. In addition, phytoplankton producing DSP toxins have been identified in temperate coastal waters worldwide, and their numbers may be increasing as a result of coastal eutrophication. The toxic effects of the major DSP toxins, okadaic acid and dinophysistoxin-1 (35-methylokadaic acid), appear to originate from their inhibitory activity against a family of structurally related serine/threonine protein phosphatases (PSPases). In particular, the inhibition of essential PSPases (e.g. PP1 and PP2A) has catastrophic consequences in most eukaryonic cells. Exploiting the potent inhibitory property of the DSP toxins, we have developed an enzyme-based assay (PP2A assay) capable of detecting both okadaic acid and dinophysistoxin-1 in nanogram amounts. The assay employs purified PP2A, which has an extremely high affinity for both DSP toxins. This provides the PP2A assay with a level of sensitivity comparable to, or surpassing, that of most monoclonal antibody probes. To evaluate the PP2A assay as a means of detecting contaminated shellfish, a series of spike recovery experiments was conducted. The findings from these studies suggest that the PP2A assay has the potential for development into a rapid and relatively simple method for detecting PSPase inhibitors in crude extracts produced from shellfish.

Is phospholipase in vinegared oysters a casual agent for human poisoning?

In this survey, lipid metabolism and activities of the lipolytic enzymes diglyceride lipase (DLase) and phospholipase A (PLase A) in the oyster digestive glands (ODGs), with 4% added acetic acid (the same acid concentration as vinegar) and incubated at 37 degrees C for 3 h, were investigated. Significant decreases in triglyceride, phosphatidycholine, and phosphatidylethanolamine and increases in monoglyceride, lysophosphatidylcholine, and lysophosphatidylethanolamine were observed in the acetic acid-treated ODGs. Changes in ODGs treated with PBS were smaller than in the acetic acid-treated ones but larger than in the nontreated ones. Both PLase A1, and PLase A2 in ODGs were activated by addition of acetic acid and incubated at 37 degrees C for 3 h. PLase A1 activities were higher than those of PLase A2, in all experimental ODGs. Addition of formic acid also induced activation of PLase A at pH 2. On the other hand, DLase in ODGs decreased remarkably with acetic acid treatment. These data showed that the increase in lipid metabolites such as free fatty acids and lysophospholipids in the acetic acid-treated ODGs might be due to catabolism of PLase A, which was activated by the acid treatment at 37 degrees C.

Myoglobinuria due to quail poisoning.

Quail poisoning is known to produce an acute myoglobinuric syndrome. The cause of this syndrome is still unknown. It has been suggested that a toxic effect or a genetic sensitivity plays a major role. Ten patients with a history of quail poisoning were examined to determine their present state and the course of the disease. A muscle biopsy was performed in 2 of these patients who complained of muscle cramps after exercise. The activities of several glycolytic mitochondrial and lipolytic enzymes were estimated. In all 10 patients the physical examination, electromyogram findings and conduction velocities were normal. Serum levels of CK, aldolase and lactic acid were also within normal range. In the 2 patients with cramps, all enzyme activities were normal in muscle tissue. Our findings possibly exclude a preexisting enzyme defect as a cause of myoglobinuria in quail poisoning. Considering that 4 of our patients continued the consumption of quails without further problems, we suggest that the major factor contributing to quail poisoning must be toxic.

Creatine kinase MB elevation in paralytic shellfish poisoning.

An outbreak of paralytic shellfish poisoning occurred in southern Taiwan, affecting 116 persons who had consumed purple clams. Two victims died within four hours. Gonyautoxins were identified as causative toxins. During the outbreak, five patients with paralytic shellfish poisoning were seen in our hospital. All recovered following supportive treatments. Serum creatine kinase concentration was elevated in three of the five patients. The levels of the enzyme did not seem to correlate with the severity of poisoning. The most significant finding was the previously unreported observation of elevation of the creatine kinase MB level. In all four patients who had creatine kinase MB value determined, it was elevated.

[Enzyme characteristics of food poisoning caused by grain contaminated with Fusarium sporotrichiella]. / Fermentnaia kharakteristika alimentarnogo toksikoza, vyzvannogo zernom, zarazhennym Fusarium sporotrichiella.

Subacute experiments were made to examine the effect of the grain contaminated with Fusarium sporotrichiella on the activity of organelle-specific enzymes of the liver, thymus, spleen, bone marrow and blood serum of rats (beta-N-acetylglucosaminidase, alpha-mannosidase, beta-galactosidase, arylsulfatases A and B, succinate dehydrogenase, glucose-6-phosphatase, alkaline phosphatase, ketoso-1-phosphate aldolase) and on the protein content. The feeding of the grain provoked an early appearance of the symptoms of intoxication and a change in the activity of organelle-specific enzymes manifesting in the activation of lysosomal hydrolases in the thymus, bone marrow and spleen and in a decrease in the blood serum activity of the most enzymes investigated.