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Toxins, Volume 5, Issue 3 (March 2013), Pages 472-604

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Research

Open AccessArticle P2X Receptor-Dependent Erythrocyte Damage by α-Hemolysin from Escherichia coli Triggers Phagocytosis by THP-1 Cells
Toxins 2013, 5(3), 472-487; doi:10.3390/toxins5030472
Received: 7 January 2013 / Revised: 6 February 2013 / Accepted: 18 February 2013 / Published: 5 March 2013
Cited by 5 | PDF Full-text (826 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The pore-forming exotoxin α-hemolysin from E. coli causes a significant volume reduction of human erythrocytes that precedes the ultimate swelling and lysis. This shrinkage results from activation of Ca2+-sensitive K+ (KCa3.1) and Cl channels (TMEM16A) and [...] Read more.
The pore-forming exotoxin α-hemolysin from E. coli causes a significant volume reduction of human erythrocytes that precedes the ultimate swelling and lysis. This shrinkage results from activation of Ca2+-sensitive K+ (KCa3.1) and Cl channels (TMEM16A) and reduced functions of either of these channels potentiate the HlyA-induced hemolysis. This means that Ca2+-dependent activation of KCa3.1 and TMEM16A protects the cells against early hemolysis. Simultaneous to the HlyA-induced shrinkage, the erythrocytes show increased exposure of phosphatidylserine (PS) in the outer plasma membrane leaflet, which is known to be a keen trigger for phagocytosis. We hypothesize that exposure to HlyA elicits removal of the damaged erythrocytes by phagocytic cells. Cultured THP-1 cells as a model for erythrocytal phagocytosis was verified by a variety of methods, including live cell imaging. We consistently found the HlyA to very potently trigger phagocytosis of erythrocytes by THP-1 cells. The HlyA-induced phagocytosis was prevented by inhibition of KCa3.1, which is known to reduce PS-exposure in human erythrocytes subjected to both ionomycin and HlyA. Moreover, we show that P2X receptor inhibition, which prevents the cell damages caused by HlyA, also reduced that HlyA-induced PS-exposure and phagocytosis. Based on these results, we propose that erythrocytes, damaged by HlyA-insertion, are effectively cleared from the blood stream. This mechanism will potentially reduce the risk of intravascular hemolysis. Full article
(This article belongs to the Special Issue Pore-Forming Toxins)
Open AccessArticle Diversity of Pea-Associated F. proliferatum and F. verticillioides Populations Revealed by FUM1 Sequence Analysis and Fumonisin Biosynthesis
Toxins 2013, 5(3), 488-503; doi:10.3390/toxins5030488
Received: 2 January 2013 / Revised: 25 January 2013 / Accepted: 22 February 2013 / Published: 7 March 2013
Cited by 11 | PDF Full-text (257 KB) | HTML Full-text | XML Full-text
Abstract
Fusarium proliferatum and F. verticillioides are considered as minor pathogens of pea (Pisum sativum L.). Both species can survive in seed material without visible disease symptoms, but still contaminating it with fumonisins. Two populations of pea-derived F. proliferatum and F. verticillioides [...] Read more.
Fusarium proliferatum and F. verticillioides are considered as minor pathogens of pea (Pisum sativum L.). Both species can survive in seed material without visible disease symptoms, but still contaminating it with fumonisins. Two populations of pea-derived F. proliferatum and F. verticillioides strains were subjected to FUM1 sequence divergence analysis, forming a distinct group when compared to the collection strains originating from different host species. Furthermore, the mycotoxigenic abilities of those strains were evaluated on the basis of in planta and in vitro fumonisin biosynthesis. No differences were observed in fumonisin B (FB) levels measured in pea seeds (maximum level reached 1.5 μg g−1); however, in rice cultures, the majority of F. proliferatum genotypes produced higher amounts of FB1–FB3 than F. verticillioides strains. Full article
Open AccessArticle Multi-Mycotoxin Screening Reveals the Occurrence of 139 Different Secondary Metabolites in Feed and Feed Ingredients
Toxins 2013, 5(3), 504-523; doi:10.3390/toxins5030504
Received: 14 December 2012 / Revised: 7 February 2013 / Accepted: 22 February 2013 / Published: 8 March 2013
Cited by 64 | PDF Full-text (260 KB) | HTML Full-text | XML Full-text
Abstract
The development of liquid chromatography-mass spectrometry (LC-MS)/mass spectrometry (MS) methods for the simultaneous detection and quantification of a broad spectrum of mycotoxins has facilitated the screening of a larger number of samples for contamination with a wide array of less well-known “emerging” [...] Read more.
The development of liquid chromatography-mass spectrometry (LC-MS)/mass spectrometry (MS) methods for the simultaneous detection and quantification of a broad spectrum of mycotoxins has facilitated the screening of a larger number of samples for contamination with a wide array of less well-known “emerging” mycotoxins and other metabolites. In this study, 83 samples of feed and feed raw materials were analysed. All of them were found to contain seven to 69 metabolites. The total number of detected metabolites amounts to 139. Fusarium mycotoxins were most common, but a number of Alternaria toxins also occurred very often. Furthermore, two so-called masked mycotoxins (i.e., mycotoxin conjugates), namely deoxynivalenol-3-glucoside (75% positives) and zearalenone-4-sulfate (49% positives), were frequently detected. Although the observed median concentrations of the individual analytes were generally in the low μg/kg range, evaluating the toxicological potential of a given sample is difficult. Toxicity data on less well-known mycotoxins and other detected metabolites are notoriously scarce, as an overview on the available information on the most commonly detected metabolites shows. Besides, the possible synergistic effects of co-occurring substances have to be considered. Full article
(This article belongs to the Special Issue Mycotoxins in Food and Feed)
Open AccessArticle Safety of Botulinum Toxin A in Children and Adolescents with Cerebral Palsy in a Pragmatic Setting
Toxins 2013, 5(3), 524-536; doi:10.3390/toxins5030524
Received: 17 January 2013 / Revised: 20 February 2013 / Accepted: 4 March 2013 / Published: 12 March 2013
Cited by 10 | PDF Full-text (198 KB) | HTML Full-text | XML Full-text
Abstract
This retrospective study aimed to examine the safety of botulinum toxin A (BoNT-A) treatment in a paediatric multidisciplinary cerebral palsy clinic. In a sample of 454 patients who had 1515 BoNT-A sessions, data on adverse events were available in 356 patients and [...] Read more.
This retrospective study aimed to examine the safety of botulinum toxin A (BoNT-A) treatment in a paediatric multidisciplinary cerebral palsy clinic. In a sample of 454 patients who had 1515 BoNT-A sessions, data on adverse events were available in 356 patients and 1382 sessions; 51 non-fatal adverse events were reported (3.3% of the total injections number, 8.7% of the patients). On five occasions, the adverse reactions observed in GMFCS V children were attributed to the sedation used (rectal midazolam plus pethidine; buccal midazolam) and resulted in prolongation of hospitalization. Of the reactions attributed to the toxin, 23 involved an excessive reduction of the muscle tone either of the injected limb(s) or generalized; others included local pain, restlessness, lethargy with pallor, disturbance in swallowing and speech production, seizures, strabismus, excessive sweating, constipation, vomiting, a flu-like syndrome and emerging hypertonus in adjacent muscles. Their incidence was associated with GMFCS level and with the presence of epilepsy (Odds ratio (OR) = 2.74 − p = 0.016 and OR = 2.35 − p = 0.046, respectively) but not with BoNT-A dose (either total or per kilogram). In conclusion, treatment with BoNT-A was safe; adverse reactions were mostly mild even for severely affected patients. Their appearance did not necessitate major changes in our practice. Full article
Open AccessArticle Sequence Divergence of the Enniatin Synthase Gene in Relation to Production of Beauvericin and Enniatins in Fusarium Species
Toxins 2013, 5(3), 537-555; doi:10.3390/toxins5030537
Received: 2 January 2013 / Revised: 25 February 2013 / Accepted: 5 March 2013 / Published: 13 March 2013
Cited by 11 | PDF Full-text (705 KB) | HTML Full-text | XML Full-text
Abstract
Beauvericin (BEA) and enniatins (ENNs) are cyclic peptide mycotoxins produced by a wide range of fungal species, including pathogenic Fusaria. Amounts of BEA and ENNs were quantified in individual rice cultures of 58 Fusarium strains belonging to 20 species, originating from different [...] Read more.
Beauvericin (BEA) and enniatins (ENNs) are cyclic peptide mycotoxins produced by a wide range of fungal species, including pathogenic Fusaria. Amounts of BEA and ENNs were quantified in individual rice cultures of 58 Fusarium strains belonging to 20 species, originating from different host plant species and different geographical localities. The species identification of all strains was done on the basis of the tef-1α gene sequence. The main aim of this study was to analyze the variability of the esyn1 gene encoding the enniatin synthase, the essential enzyme of this metabolic pathway, among the BEA- and ENNs-producing genotypes. The phylogenetic analysis based on the partial sequence of the esyn1 gene clearly discriminates species producing exclusively BEA from those synthesizing mainly enniatin analogues. Full article
Open AccessArticle Dog Poisonings Associated with a Microcystis aeruginosa Bloom in the Netherlands
Toxins 2013, 5(3), 556-567; doi:10.3390/toxins5030556
Received: 24 December 2012 / Revised: 26 February 2013 / Accepted: 6 March 2013 / Published: 14 March 2013
Cited by 15 | PDF Full-text (675 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
In early autumn 2011, three dogs died after they had been exposed to a Microcystis aeruginosa bloom on Lake Amstelmeer, The Netherlands. The cyanobacterial scum from the lake contained up to 5.27 × 103 μg g−1 dry-weight microcystin, the vomit [...] Read more.
In early autumn 2011, three dogs died after they had been exposed to a Microcystis aeruginosa bloom on Lake Amstelmeer, The Netherlands. The cyanobacterial scum from the lake contained up to 5.27 × 103 μg g−1 dry-weight microcystin, the vomit of one of the dogs contained on average 94 µg microcystin g−1 dry-weight. In both cases, microcystin-LR was the most abundant variant. This is the first report of dog deaths associated with a Microcystis bloom and microcystin poisoning in The Netherlands. Full article
(This article belongs to the Special Issue Cyanotoxins)
Open AccessArticle Cloning and Characterization of a Hybridoma Secreting a 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-Specific Monoclonal Antibody and Recombinant F(ab)
Toxins 2013, 5(3), 568-589; doi:10.3390/toxins5030568
Received: 9 January 2013 / Revised: 28 February 2013 / Accepted: 5 March 2013 / Published: 19 March 2013
Cited by 2 | PDF Full-text (785 KB) | HTML Full-text | XML Full-text
Abstract
Smokeless tobacco products have been associated with increased risks of oro-pharyngeal cancers, due in part to the presence of tobacco-specific nitrosamines (TSNAs) such as 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). These potent carcinogens are formed during tobacco curing and as a result of direct nitrosation reactions [...] Read more.
Smokeless tobacco products have been associated with increased risks of oro-pharyngeal cancers, due in part to the presence of tobacco-specific nitrosamines (TSNAs) such as 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). These potent carcinogens are formed during tobacco curing and as a result of direct nitrosation reactions that occur in the oral cavity. In the current work we describe the isolation and characterization of a hybridoma secreting a high-affinity, NNK-specific monoclonal antibody. A structurally-related benzoyl derivative was synthesized to facilitate coupling to NNK-carrier proteins, which were characterized for the presence of the N-nitroso group using the Griess reaction, and used to immunize BALB/c mice. Splenocytes from mice bearing NNK-specific antibodies were used to create hybridomas. Out of four, one was selected for subcloning and characterization. Approximately 99% of the monoclonal antibodies from this clone were competitively displaced from plate-bound NNKB conjugates in the presence of free NNK. The affinity of the monoclonal antibody to the NNKB conjugates was Kd = 2.93 nM as determined by surface plasmon resonance. Free nicotine was a poor competitor for the NNKB binding site. The heavy and light chain antibody F(ab) fragments were cloned, sequenced and inserted in tandem into an expression vector, with an FMDV Furin 2A cleavage site between them. Expression in HEK 293 cells revealed a functional F(ab) with similar binding features to that of the parent hybridoma. This study lays the groundwork for synthesizing transgenic tobacco that expresses carcinogen-sequestration properties, thereby rendering it less harmful to consumers. Full article
(This article belongs to the Special Issue Toxin-Antibody Interactions)
Open AccessArticle Detection of Type A Trichothecene Di-Glucosides Produced in Corn by High-Resolution Liquid Chromatography-Orbitrap Mass Spectrometry
Toxins 2013, 5(3), 590-604; doi:10.3390/toxins5030590
Received: 26 February 2013 / Revised: 19 March 2013 / Accepted: 19 March 2013 / Published: 22 March 2013
Cited by 15 | PDF Full-text (275 KB) | HTML Full-text | XML Full-text
Abstract
The existence of di-glucosylated derivative of T-2 toxin in plant (corn powder) was confirmed for the first time in addition to that of HT-2 toxin. These masked mycotoxins (mycotoxin glucosides) were identified as T-2 toxin-di-glucoside (T2GlcGlc) and HT-2 toxin-di-glucoside (HT2GlcGlc) based on [...] Read more.
The existence of di-glucosylated derivative of T-2 toxin in plant (corn powder) was confirmed for the first time in addition to that of HT-2 toxin. These masked mycotoxins (mycotoxin glucosides) were identified as T-2 toxin-di-glucoside (T2GlcGlc) and HT-2 toxin-di-glucoside (HT2GlcGlc) based on accurate mass measurements of characteristic ions and fragmentation patterns using high-resolution liquid chromatography-Orbitrap mass spectrometric (LC-Orbitrap MS) analysis. Although the absolute structure of T2GlcGlc was not clarified, two glucose molecules were suggested to be conjugated at 3-OH position in tandem when considering the structure of T-2 toxin. On the other hand, the specification of the structure seems to be more complicated in the case of HT2GlcGlc, since HT-2 toxin has two possible positions (at 3-OH and 4-OH) to be glusocylated. In addition, 15-monoacetoxyscirpenol-glucoside (MASGlc) was also detected in the identical sample. Full article
(This article belongs to the Special Issue Mycotoxins in Food and Feed)

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