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Toxins, Volume 6, Issue 9 (September 2014), Pages 2594-2871

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Research

Jump to: Review

Open AccessArticle Okinalysin, a Novel P-I Metalloproteinase from Ovophis okinavensis: Biological Properties and Effect on Vascular Endothelial Cells
Toxins 2014, 6(9), 2594-2604; doi:10.3390/toxins6092594
Received: 18 July 2014 / Accepted: 18 August 2014 / Published: 25 August 2014
Cited by 1 | PDF Full-text (540 KB) | HTML Full-text | XML Full-text
Abstract
A novel hemorrhagic metalloproteinase, okinalysin, was isolated from the venom of Ovophis okinavensis. It possessed caseinolytic and hemorrhagic activities, and also hydrolyzed fibrinogen and collagen. These activities were inhibited by ethylenediaminetetraacetic acid (EDTA) but not by p-amidinophenyl methanesulfonyl fluoride hydrochloride [...] Read more.
A novel hemorrhagic metalloproteinase, okinalysin, was isolated from the venom of Ovophis okinavensis. It possessed caseinolytic and hemorrhagic activities, and also hydrolyzed fibrinogen and collagen. These activities were inhibited by ethylenediaminetetraacetic acid (EDTA) but not by p-amidinophenyl methanesulfonyl fluoride hydrochloride (APMSF). The molecular mass of okinalysin was 22,202 Da measured by MALDI/TOF mass spectrometry. The primary structure of okinalysin was partially determined by Edman sequencing, and the putative zinc-binding domain HEXXHXXGXXH was found to be present in its structure. From these data, okinalysin is defined as a metalloproteinase belonging to a P-I class. The partial amino acid sequence of okinalysin was homologous to the C-terminus of MP 10, a putative metalloproteinase induced from transcriptome of the venom gland cDNA sequencing of O. okinavensis. Okinalysin possessed cytotoxic activity on cultured endothelial cells, and the EC50 on human pulmonary artery endothelial cells was determined to be 0.6 μg/mL. The histopathological study also showed that okinalysin causes the leakage of red blood cells and neutrophil infiltration. These results indicate that destruction of blood vessels by okinalysin is one of the main causes of hemorrhage. Full article
(This article belongs to the Special Issue Antivenom and Venom Therapeutics)
Open AccessArticle Uremic Toxins Enhance Statin-Induced Cytotoxicity in Differentiated Human Rhabdomyosarcoma Cells
Toxins 2014, 6(9), 2612-2625; doi:10.3390/toxins6092612
Received: 2 June 2014 / Revised: 29 August 2014 / Accepted: 29 August 2014 / Published: 3 September 2014
Cited by 1 | PDF Full-text (578 KB) | HTML Full-text | XML Full-text
Abstract
The risk of myopathy and rhabdomyolysis is considerably increased in statin users with end-stage renal failure (ESRF). Uremic toxins, which accumulate in patients with ESRF, exert cytotoxic effects that are mediated by various mechanisms. Therefore, accumulation of uremic toxins might increase statin-induced [...] Read more.
The risk of myopathy and rhabdomyolysis is considerably increased in statin users with end-stage renal failure (ESRF). Uremic toxins, which accumulate in patients with ESRF, exert cytotoxic effects that are mediated by various mechanisms. Therefore, accumulation of uremic toxins might increase statin-induced cytotoxicity. The purpose of this study was to determine the effect of four uremic toxins—hippuric acid, 3-carboxy-4-methyl-5-propyl-2-furanpropionate, indole-3-acetic acid, and 3-indoxyl sulfate—on statin-induced myopathy. Differentiated rhabdomyosarcoma cells were pre-treated with the uremic toxins for seven days, and then the cells were treated with pravastatin or simvastatin. Cell viability and apoptosis were assessed by viability assays and flow cytometry. Pre-treatment with uremic toxins increased statin- but not cisplatin-induced cytotoxicity (p < 0.05 vs. untreated). In addition, the pre-treatment increased statin-induced apoptosis, which is one of the cytotoxic factors (p < 0.05 vs. untreated). However, mevalonate, farnesol, and geranylgeraniol reversed the effects of uremic toxins and lowered statin-induced cytotoxicity (p < 0.05 vs. untreated). These results demonstrate that uremic toxins enhance statin-induced apoptosis and cytotoxicity. The mechanism underlying this effect might be associated with small G-protein geranylgeranylation. In conclusion, the increased severity of statin-induced rhabdomyolysis in patients with ESRF is likely due to the accumulation of uremic toxins. Full article
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Open AccessArticle Application of Hydrogen Peroxide to the Control of Eutrophic Lake Systems in Laboratory Assays
Toxins 2014, 6(9), 2657-2675; doi:10.3390/toxins6092657
Received: 11 March 2014 / Revised: 13 August 2014 / Accepted: 18 August 2014 / Published: 9 September 2014
Cited by 3 | PDF Full-text (978 KB) | HTML Full-text | XML Full-text
Abstract
We exposed water samples from a recreational lake dominated by the cyanobacterium Planktothrix agardhii to different concentrations of hydrogen peroxide (H2O2). An addition of 0.33 mg·L−1 of H2O2 was the lowest effective dose for [...] Read more.
We exposed water samples from a recreational lake dominated by the cyanobacterium Planktothrix agardhii to different concentrations of hydrogen peroxide (H2O2). An addition of 0.33 mg·L−1 of H2O2 was the lowest effective dose for the decay of chlorophyll-a concentration to half of the original in 14 h with light and 17 h in experiments without light. With 3.33 mg·L−1 of H2O2, the values of the chemical oxygen demand (COD) decreased to half at 36 and 126 h in experiments performed with and without light, respectively. With increasing H2O2, there is a decrease in the total and faecal coliform, and this effect was made more pronounced by light. Total and faecal coliform were inhibited completely 48 h after addition of 3.33 mg·L−1 H2O2. Although the densities of cyanobacterial cells exposed to H2O2 did not decrease, transmission electron microscope observation of the trichomes showed several stages of degeneration, and the cells were collapsed after 48 h of 3.33 mg·L−1 of H2O2 addition in the presence of light. Our results demonstrate that H2O2 could be potentially used in hypertrophic systems because it not only collapses cyanobacterial cells and coliform bacteria but may also reduce chlorophyll-a content and chemical oxygen demand. Full article
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Open AccessArticle Downregulation and Mutation of a Cadherin Gene Associated with Cry1Ac Resistance in the Asian Corn Borer, Ostrinia furnacalis (Guenée)
Toxins 2014, 6(9), 2676-2693; doi:10.3390/toxins6092676
Received: 30 April 2014 / Revised: 13 August 2014 / Accepted: 15 August 2014 / Published: 11 September 2014
Cited by 5 | PDF Full-text (732 KB) | HTML Full-text | XML Full-text
Abstract
Development of resistance in target pests is a major threat to long-term use of transgenic crops expressing Bacillus thuringiensis (Bt) Cry toxins. To manage and/or delay the evolution of resistance in target insects through the implementation of effective strategies, it [...] Read more.
Development of resistance in target pests is a major threat to long-term use of transgenic crops expressing Bacillus thuringiensis (Bt) Cry toxins. To manage and/or delay the evolution of resistance in target insects through the implementation of effective strategies, it is essential to understand the basis of resistance. One of the most important mechanisms of insect resistance to Bt crops is the alteration of the interactions between Cry toxins and their receptors in the midgut. A Cry1Ac-selected strain of Asian corn borer (ACB), Ostrinia furnacalis, a key pest of maize in China, evolved three mutant alleles of a cadherin-like protein (OfCAD) (MPR-r1, MPR-r2 and MPR-r3), which mapped within the toxin-binding region (TBR). Each of the three mutant alleles possessed two or three amino acid substitutions in this region, especially Thr1457→Ser. In highly resistant larvae (ACB-Ac200), MPR-r2 had a 26-amino acid residue deletion in the TBR, which resulted in reduced binding of Cry1Ac compared to the MPR from the susceptible strain, suggesting that the number of amino acid deletions influences the level of resistance. Furthermore, downregulation of OfCAD gene (ofcad) transcription was observed in the Cry1Ac resistant strain, ACB-Ac24, suggesting that Cry1Ac resistance in ACB is associated with the downregulation of the transcript levels of the cadherin-like protein gene. The OfCAD identified from ACB exhibited a high degree of similarity to other members of the cadherin super-family in lepidopteran species. Full article
(This article belongs to the Special Issue <i>Bacillus thuringiensis</i> Toxins)
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Open AccessArticle Inheritance Patterns, Dominance and Cross-Resistance of Cry1Ab- and Cry1Ac-Selected Ostrinia furnacalis (Guenée)
Toxins 2014, 6(9), 2694-2707; doi:10.3390/toxins6092694
Received: 30 April 2014 / Revised: 13 August 2014 / Accepted: 18 August 2014 / Published: 11 September 2014
Cited by 6 | PDF Full-text (572 KB) | HTML Full-text | XML Full-text
Abstract
Two colonies of Asian corn borer, Ostrinia furnacalis (Guenée), artificially selected from a Bt-susceptible colony (ACB-BtS) for resistance to Cry1Ab (ACB-AbR) and Cry1Ac (ACB-AcR) toxins, were used to analyze inheritance patterns of resistance to Cry1 toxins. ACB-AbR and ACB-AcR evolved significant levels [...] Read more.
Two colonies of Asian corn borer, Ostrinia furnacalis (Guenée), artificially selected from a Bt-susceptible colony (ACB-BtS) for resistance to Cry1Ab (ACB-AbR) and Cry1Ac (ACB-AcR) toxins, were used to analyze inheritance patterns of resistance to Cry1 toxins. ACB-AbR and ACB-AcR evolved significant levels of resistance, with resistance ratios (RR) of 39-fold and 78.8-fold to Cry1Ab and Cry1Ac, respectively. The susceptibility of ACB-AbR larvae to Cry1Ac and Cry1F toxins, which had not previously been exposed, were significantly reduced, being >113-fold and 48-fold, respectively. Similarly, susceptibility of ACB-AcR larvae to Cry1Ab and Cry1F were also significantly reduced (RR > nine-fold, RR > 18-fold, respectively), indicating cross-resistance among Cry1Ab, Cry1Ac, and Cry1F toxins. However, ACB-AbR and ACB-AcR larvae were equally susceptible to Cry1Ie as were ACB-BtS larvae, indicating no cross-resistance between Cry1Ie and Cry1Ab or Cry1Ac toxins; this may provide considerable benefits in preventing or delaying the evolution of resistance in ACB to Cry1Ab and Cry1Ac toxins. Backcrossing studies indicated that resistance to Cry1Ab toxin was polygenic in ACB-AbR, but monogenic in ACB-AcR, whilst resistance to Cry1Ac toxin was primarily monogenic in both ACB-AbR and ACB-AcR, but polygenic as resistance increased. Full article
(This article belongs to the Special Issue <i>Bacillus thuringiensis</i> Toxins)
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Open AccessArticle Effects of Fraxinellone on the Midgut Enzyme Activities of the 5th Instar Larvae of Oriental Armyworm, Mythimna separata Walker
Toxins 2014, 6(9), 2708-2718; doi:10.3390/toxins6092708
Received: 4 May 2014 / Revised: 28 August 2014 / Accepted: 29 August 2014 / Published: 11 September 2014
Cited by 1 | PDF Full-text (545 KB) | HTML Full-text | XML Full-text
Abstract
Isolated from Dictamnus dasycarpus Turcz., fraxinellone exhibited multiple bioactivities against insects. In the present paper, the changes of digestive enzymes and detoxification enzymes of Mythimna separata Walker (5th instar larvae), treated with fraxinellone, were investigated. Compared with those of the control, the [...] Read more.
Isolated from Dictamnus dasycarpus Turcz., fraxinellone exhibited multiple bioactivities against insects. In the present paper, the changes of digestive enzymes and detoxification enzymes of Mythimna separata Walker (5th instar larvae), treated with fraxinellone, were investigated. Compared with those of the control, the α-amylase activity of the fraxinellone-treated 5th instar larvae was inhibited, whereas the level of their protease activity was increased. Based upon further studies on the specific proteases, the levels of the active alkaline trypsin-like enzyme (BApNA as the substrate) and the chymotrypsin-like enzyme (BTEE as the substrate) activities of the treated larvae were declined; however, the level of activity of the weak alkaline trypsin-like enzyme (TAME as the substrate) of the treated ones was increased. Meanwhile, the activities of two detoxification enzymes, such as carboxylesterase (CarE) and glutathione S-transferase (GST), of the treated larvae were increased to some extent, but the activities of NADPH-P450 reductase and O-demethylase of the treated ones declined. Therefore, protease (especially the weak alkaline trypsin-like enzyme), CarE and GST played important roles in the metabolism of fraxinellone in the midgut of Mythimna separata (M. separata). Full article
Open AccessArticle Biochemical Characterization of the SPATE Members EspPα and EspI
Toxins 2014, 6(9), 2719-2731; doi:10.3390/toxins6092719
Received: 3 July 2014 / Revised: 18 August 2014 / Accepted: 21 August 2014 / Published: 16 September 2014
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Abstract
The activity of serine proteases is influenced by their substrate specificity as well as by the physicochemical conditions. Here, we present the characterization of key biochemical features of the two SPATE members EspPα and EspI from Shiga-toxin producing Escherichia coli (STEC) and [...] Read more.
The activity of serine proteases is influenced by their substrate specificity as well as by the physicochemical conditions. Here, we present the characterization of key biochemical features of the two SPATE members EspPα and EspI from Shiga-toxin producing Escherichia coli (STEC) and enterohemorrhagic E. coli (EHEC). Both proteases show high activity at conditions mimicking the human blood stream. Optimal activities were observed at slightly alkaline pH and low millimolar concentrations of the divalent cations Ca2+ and Mg2+ at physiological temperatures indicating a function in the human host. Furthermore, we provide the first cleavage profile for EspI demonstrating pronounced specificity of this protease. Full article
(This article belongs to the Section Bacterial Toxins)
Open AccessArticle In Vitro Sensitization of Erythrocytes to Programmed Cell Death Following Baicalein Treatment
Toxins 2014, 6(9), 2771-2786; doi:10.3390/toxins6092771
Received: 9 May 2014 / Revised: 3 September 2014 / Accepted: 4 September 2014 / Published: 18 September 2014
Cited by 2 | PDF Full-text (716 KB) | HTML Full-text | XML Full-text
Abstract
The polyphenolic flavonoid Baicalein has been shown to trigger suicidal death or apoptosis of tumor cells and is thus considered for the prevention and treatment of malignancy. Similar to apoptosis of nucleated cells, erythrocytes may enter eryptosis, the suicidal erythrocyte death characterized [...] Read more.
The polyphenolic flavonoid Baicalein has been shown to trigger suicidal death or apoptosis of tumor cells and is thus considered for the prevention and treatment of malignancy. Similar to apoptosis of nucleated cells, erythrocytes may enter eryptosis, the suicidal erythrocyte death characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Stimulators of eryptosis include increase of cytosolic Ca2+-activity ([Ca2+]i) and ceramide. The present study explored whether Baicalein stimulates eryptosis. To this end, forward scatter was taken for measurement of cell volume, annexin-V-binding for phosphatidylserine-exposure, Fluo3 fluorescence for [Ca2+]i and fluorescent antibodies for ceramide abundance. As a result, a 48 h exposure of human erythrocytes to Baicalein was followed by significant decrease of forward scatter (≥10 µM), significant increase of the percentage of annexin-V-binding cells (≥25 µM), significant increase of [Ca2+]i (50 µM) and significant increase of ceramide abundance (50 µM). The effect of Baicalein (50 µM) on annexin-V-binding was significantly blunted but not abrogated by removal of extracellular Ca2+. In conclusion, at the concentrations employed, Baicalein stimulates suicidal erythrocyte death or eryptosis, an effect at least in part due to the combined effects of Ca2+ entry and ceramide formation. Full article
Open AccessArticle Toxin ζ Reversible Induces Dormancy and Reduces the UDP-N-Acetylglucosamine Pool as One of the Protective Responses to Cope with Stress
Toxins 2014, 6(9), 2787-2803; doi:10.3390/toxins6092787
Received: 18 June 2014 / Revised: 14 August 2014 / Accepted: 9 September 2014 / Published: 18 September 2014
Cited by 5 | PDF Full-text (766 KB) | HTML Full-text | XML Full-text
Abstract
Toxins of the ζ/PezT family, found in the genome of major human pathogens, phosphorylate the peptidoglycan precursor uridine diphosphate-N-acetylglucosamine (UNAG) leading to unreactive UNAG-3P. Transient over-expression of a PezT variant impairs cell wall biosynthesis and triggers autolysis in Escherichia coli [...] Read more.
Toxins of the ζ/PezT family, found in the genome of major human pathogens, phosphorylate the peptidoglycan precursor uridine diphosphate-N-acetylglucosamine (UNAG) leading to unreactive UNAG-3P. Transient over-expression of a PezT variant impairs cell wall biosynthesis and triggers autolysis in Escherichia coli. Conversely, physiological levels of ζ reversibly induce dormancy produce a sub-fraction of membrane-compromised cells, and a minor subpopulation of Bacillus subtilis cells become tolerant of toxin action. We report here that purified ζ is a strong UNAG-dependent ATPase, being GTP a lower competitor. In vitro, ζ toxin phosphorylates a fraction of UNAG. In vivo, ζ-mediated inactivation of UNAG by phosphorylation does not deplete the active UNAG pool, because expression of the toxin enhances the efficacy of genuine cell wall inhibitors (fosfomycin, vancomycin or ampicillin). Transient ζ expression together with fosfomycin treatment halt cell proliferation, but ε2 antitoxin expression facilitates the exit of ζ-induced dormancy, suggesting that there is sufficient UNAG for growth. We propose that ζ induces diverse cellular responses to cope with stress, being the reduction of the UNAG pool one among them. If the action of ζ is not inhibited, e.g., by de novo ε2 antitoxin synthesis, the toxin markedly enhances the efficacy of antimicrobial treatment without massive autolysis in Firmicutes. Full article
(This article belongs to the Special Issue Toxin-Antitoxin System)
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Open AccessArticle Fumonisins in Conventional and Transgenic, Insect-Resistant Maize Intended for Fuel Ethanol Production: Implications for Fermentation Efficiency and DDGS Co-Product Quality
Toxins 2014, 6(9), 2804-2825; doi:10.3390/toxins6092804
Received: 6 August 2014 / Revised: 5 September 2014 / Accepted: 9 September 2014 / Published: 22 September 2014
Cited by 1 | PDF Full-text (742 KB) | HTML Full-text | XML Full-text
Abstract
Mycotoxins in maize grain intended for ethanol production are enriched in co-product dried distiller’s grains and solubles (DDGS) and may be detrimental to yeast in fermentation. This study was conducted to examine the magnitude of fumonisin enrichment in DDGS and to analyze [...] Read more.
Mycotoxins in maize grain intended for ethanol production are enriched in co-product dried distiller’s grains and solubles (DDGS) and may be detrimental to yeast in fermentation. This study was conducted to examine the magnitude of fumonisin enrichment in DDGS and to analyze the impacts of insect injury, Fusarium ear rot severity, and fumonisin contamination on final ethanol yield. Samples of naturally-contaminated grain (0 to 35 mg/kg fumonisins) from field trials conducted in 2008–2011 were fermented and DDGS collected and analyzed for fumonisin content. Ethanol yield (determined gravimetrically) was unaffected by fumonisins in the range occurring in this study, and was not correlated with insect injury or Fusarium ear rot severity. Ethanol production was unaffected in fumonisin B1-spiked grain with concentrations from 0 to 37 mg/kg. Bacillus thuringiensis (Bt) maize often has reduced fumonisins due to its protection from insect injury and subsequent fungal infection. DDGS derived from Bt and non-Bt maize averaged 2.04 mg/kg and 8.25 mg/kg fumonisins, respectively. Fumonisins were enriched by 3.0× for 50 out of 57 hybrid × insect infestation treatment combinations; those seven that differed were <3.0 (1.56 to 2.56×). This study supports the industry assumption of three-fold fumonisin enrichment in DDGS, with measurements traceable to individual samples. Under significant insect pest pressures, DDGS derived from Bt maize hybrids were consistently lower in fumonisins than DDGS derived from non-Bt hybrids. Full article
Open AccessArticle The Adsorption of Ochratoxin A by Lactobacillus Species
Toxins 2014, 6(9), 2826-2839; doi:10.3390/toxins6092826
Received: 10 July 2014 / Revised: 9 September 2014 / Accepted: 10 September 2014 / Published: 22 September 2014
Cited by 2 | PDF Full-text (592 KB) | HTML Full-text | XML Full-text
Abstract
The objective of this study was to examine ochratoxin A (OTA) binding by three lactic acid bacteria (LAB) species: Lactobacillus plantarum, L. brevis, and L. sanfranciscensis. Experiments were conducted using MRS medium and PBS buffer contaminated with 1000 ng/mL [...] Read more.
The objective of this study was to examine ochratoxin A (OTA) binding by three lactic acid bacteria (LAB) species: Lactobacillus plantarum, L. brevis, and L. sanfranciscensis. Experiments were conducted using MRS medium and PBS buffer contaminated with 1000 ng/mL OTA and inoculated with live or thermally inactivated bacterial biomass at a concentration of 1 or 5 mg dry weight/mL. It was found that, depending on the strain and biomass density, live bacterial cells reduced OTA content by 16.9% to 35% in MRS medium and by 14.8% to 26.4% in PBS after 24 h of contact. OTA binding was higher in the case of thermally inactivated bacterial biomass (46.2% to 59.8%). The process is very rapid: OTA was removed from PBS as early as after 30 min of contact. The binding of the toxin by cells was partially reversible under the treatment by water and 1 M HCl. The results show that OTA is adsorbed to the surface structures of the cell wall, which is promoted not only by the hydrophobic properties of the cell wall, but also by electron donor-acceptor and Lewis acid-base interactions. Full article
Open AccessArticle Oxidized Lipids and Lysophosphatidylcholine Induce the Chemotaxis, Up-Regulate the Expression of CCR9 and CXCR4 and Abrogate the Release of IL-6 in Human Monocytes
Toxins 2014, 6(9), 2840-2856; doi:10.3390/toxins6092840
Received: 24 July 2014 / Revised: 8 September 2014 / Accepted: 15 September 2014 / Published: 23 September 2014
Cited by 3 | PDF Full-text (1088 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Lipids through regulation of chronic inflammation play key roles in the development of various diseases. Here, we report that a mixed population of human primary monocytes migrated towards LPC, as well as oxidized linoleic acid isoforms 9-S-HODE, 9-R-HODE and 13-R-HODE. Incubation with [...] Read more.
Lipids through regulation of chronic inflammation play key roles in the development of various diseases. Here, we report that a mixed population of human primary monocytes migrated towards LPC, as well as oxidized linoleic acid isoforms 9-S-HODE, 9-R-HODE and 13-R-HODE. Incubation with 9-R-HODE, 13-R-HODE and LPC resulted in increased expression of CXCR4, the receptor for SDF-1α/CXCL12, correlated with increased monocyte migration towards SDF-1α/CXCL12. Further, we report increased expression of CCR9, the receptor for TECK/CCL25, after stimulation with these lipids. Upon examining the migratory response towards TECK/CCL25, it was observed that an increase in CCR9 expression upon pre-treatment with 9-S-HODE, 9-R-HODE, 13-R-HODE and LPC resulted in increased migration of monocytes expressing CCR9. Only LPC but not any other lipid examined increased the influx of intracellular Ca2+ in monocytes. Finally, 9-S-HODE, 9-R-HODE, 13-R-HODE, or LPC inhibited the release of IL-6 from monocytes suggesting that these lipids may play important role in controlling inflammatory responses. Full article
(This article belongs to the collection Toxicity and Therapeutic Interventions in the Immune System)
Open AccessArticle Ophiobolin A from Bipolaris oryzae Perturbs Motility and Membrane Integrities of Porcine Sperm and Induces Cell Death on Mammalian Somatic Cell Lines
Toxins 2014, 6(9), 2857-2871; doi:10.3390/toxins6092857
Received: 28 May 2014 / Revised: 28 August 2014 / Accepted: 1 September 2014 / Published: 23 September 2014
Cited by 4 | PDF Full-text (624 KB) | HTML Full-text | XML Full-text
Abstract
Bipolaris oryzae is a phytopathogenic fungus causing a brown spot disease in rice, and produces substance that strongly perturbs motility and membrane integrities of boar spermatozoa. The substance was isolated from the liquid culture of the fungal strain using extraction and a [...] Read more.
Bipolaris oryzae is a phytopathogenic fungus causing a brown spot disease in rice, and produces substance that strongly perturbs motility and membrane integrities of boar spermatozoa. The substance was isolated from the liquid culture of the fungal strain using extraction and a multi-step semi-preparative HPLC procedures. Based on the results of mass spectrometric and 2D NMR techniques, the bioactive molecule was identified as ophiobolin A, a previously described sesterterpene-type compound. The purified ophiobolin A exhibited strong motility inhibition and viability reduction on boar spermatozoa. Furthermore, it damaged the sperm mitochondria significantly at sublethal concentration by the dissipation of transmembrane potential in the mitochondrial inner membrane, while the plasma membrane permeability barrier remained intact. The study demonstrated that the cytotoxicity of ophiobolin A toward somatic cell lines is higher by 1–2 orders of magnitude compared to other mitochondriotoxic mycotoxins, and towards sperm cells unique by replacing the progressive motility by shivering tail beating at low exposure concentration. Full article
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Review

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Open AccessReview Aconitum Alkaloid Poisoning Related to the Culinary Uses of Aconite Roots
Toxins 2014, 6(9), 2605-2611; doi:10.3390/toxins6092605
Received: 20 July 2014 / Revised: 11 August 2014 / Accepted: 21 August 2014 / Published: 2 September 2014
Cited by 8 | PDF Full-text (459 KB) | HTML Full-text | XML Full-text
Abstract
Aconite roots (roots or root tubers of the Aconitum species) are eaten as root vegetables and used to prepare herbal soups and meals, mainly for their purported health benefits. Aconite roots contain aconitine and other Aconitum alkaloids, which are well known cardiotoxins [...] Read more.
Aconite roots (roots or root tubers of the Aconitum species) are eaten as root vegetables and used to prepare herbal soups and meals, mainly for their purported health benefits. Aconite roots contain aconitine and other Aconitum alkaloids, which are well known cardiotoxins and neurotoxins. To better understand why Aconitum alkaloid poisoning related to the culinary uses of aconite roots can occur and characterize the risks posed by these “food supplements”, relevant published reports were reviewed. From 1995 to 2013, there were eight reports of aconite poisoning after consumption of these herbal soups and meals, including two reports of large clusters of cases (n = 19–45) and two reports of cases (n = 15–156) managed by two hospitals over a period of 4.5 to 5 years. The herbal formulae used did not adhere to the suggested guidelines, with regarding to the doses (50–500 g instead of 3–30 g per person) and types (raw instead of processed) of aconite roots used. The quantities of Aconitum alkaloids involved were huge, taking into consideration the doses of aconite roots used to prepare herbal soups/meals and the amounts of aconite roots and herbal soups/meals consumed. In a large cluster of cases, despite simmering raw “caowu” (the root tuber of A. kusnezoffii) in pork broth for 24 h, all 19 family members who consumed this soup and boiled “caowu” developed poisoning. Severe or even fatal aconite poisoning can occur after consumption of herbal soups and foods prepared from aconite roots. Even prolonged boiling may not be protective if raw preparations and large quantities of aconite roots are used. The public should be warned of the risk of severe poisoning related to the culinary and traditional medicinal uses of aconite roots. Full article
(This article belongs to the Special Issue Plant Toxins)
Open AccessReview Clostridium and Bacillus Binary Enterotoxins: Bad for the Bowels, and Eukaryotic Being
Toxins 2014, 6(9), 2626-2656; doi:10.3390/toxins6092626
Received: 1 August 2014 / Revised: 22 August 2014 / Accepted: 27 August 2014 / Published: 5 September 2014
Cited by 7 | PDF Full-text (523 KB) | HTML Full-text | XML Full-text
Abstract
Some pathogenic spore-forming bacilli employ a binary protein mechanism for intoxicating the intestinal tracts of insects, animals, and humans. These Gram-positive bacteria and their toxins include Clostridium botulinum (C2 toxin), Clostridium difficile (C. difficile toxin or CDT), Clostridium perfringens (ι-toxin and [...] Read more.
Some pathogenic spore-forming bacilli employ a binary protein mechanism for intoxicating the intestinal tracts of insects, animals, and humans. These Gram-positive bacteria and their toxins include Clostridium botulinum (C2 toxin), Clostridium difficile (C. difficile toxin or CDT), Clostridium perfringens (ι-toxin and binary enterotoxin, or BEC), Clostridium spiroforme (C. spiroforme toxin or CST), as well as Bacillus cereus (vegetative insecticidal protein or VIP). These gut-acting proteins form an AB complex composed of ADP-ribosyl transferase (A) and cell-binding (B) components that intoxicate cells via receptor-mediated endocytosis and endosomal trafficking. Once inside the cytosol, the A components inhibit normal cell functions by mono-ADP-ribosylation of globular actin, which induces cytoskeletal disarray and death. Important aspects of each bacterium and binary enterotoxin will be highlighted in this review, with particular focus upon the disease process involving the biochemistry and modes of action for each toxin. Full article
Open AccessReview Structural Insights into Bacillus thuringiensis Cry, Cyt and Parasporin Toxins
Toxins 2014, 6(9), 2732-2770; doi:10.3390/toxins6092732
Received: 29 April 2014 / Revised: 26 August 2014 / Accepted: 28 August 2014 / Published: 16 September 2014
Cited by 10 | PDF Full-text (3204 KB) | HTML Full-text | XML Full-text
Abstract
Since the first X-ray structure of Cry3Aa was revealed in 1991, numerous structures of B. thuringiensis toxins have been determined and published. In recent years, functional studies on the mode of action and resistance mechanism have been proposed, which notably promoted the [...] Read more.
Since the first X-ray structure of Cry3Aa was revealed in 1991, numerous structures of B. thuringiensis toxins have been determined and published. In recent years, functional studies on the mode of action and resistance mechanism have been proposed, which notably promoted the developments of biological insecticides and insect-resistant transgenic crops. With the exploration of known pore-forming toxins (PFTs) structures, similarities between PFTs and B. thuringiensis toxins have provided great insights into receptor binding interactions and conformational changes from water-soluble to membrane pore-forming state of B. thuringiensis toxins. This review mainly focuses on the latest discoveries of the toxin working mechanism, with the emphasis on structural related progress. Based on the structural features, B. thuringiensis Cry, Cyt and parasporin toxins could be divided into three categories: three-domain type α-PFTs, Cyt toxin type β-PFTs and aerolysin type β-PFTs. Structures from each group are elucidated and discussed in relation to the latest data, respectively. Full article
(This article belongs to the Special Issue <i>Bacillus thuringiensis</i> Toxins)

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