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Toxins, Volume 13, Issue 6 (June 2021) – 67 articles

Cover Story (view full-size image): Lake Vegoritis is a beautiful natural lake covering an area of 60 km2 in the region of Western Macedonia, Greece. It belongs to the NATURA 2000 network of protected areas, and it is used for irrigation, fishing, bathing, and recreational activities. The historical background of cyanobacterial blooms in the lake creates a growing concern about the possible effects of cyanotoxins and other cyanobacterial metabolites to its ecosystem and to human health. A collaboration between researchers and water authorities of Greece resulted in a 3-year monitoring program and in the first report of the co-occurrence of cyanotoxins and cyanobacterial peptides in the lake. The findings support the need for future monitoring programs and investigations of the occurrence of cyanotoxins and other cyanobacterial metabolites, to support risk management with relevance to human exposure and ecosystem effects. [...] Read more.
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Article
Daily Headache in Chronic Migraine Is a Predictive Factor of Response in Patients Who Had Completed Three Sessions of OnabotulinumtoxinA
Toxins 2021, 13(6), 432; https://doi.org/10.3390/toxins13060432 - 21 Jun 2021
Viewed by 629
Abstract
OnabotulinumtoxinA is one of the main preventive treatments for chronic migraine. Despite that up to one third of patients with chronic migraine suffer from daily headache, these individuals have hardly been studied. We conducted a prospective cohort study, including patients with chronic migraine [...] Read more.
OnabotulinumtoxinA is one of the main preventive treatments for chronic migraine. Despite that up to one third of patients with chronic migraine suffer from daily headache, these individuals have hardly been studied. We conducted a prospective cohort study, including patients with chronic migraine and treated with OnabotulinumtoxinA according to the PREEMPT paradigm. The primary endpoint was to assess whether patients with chronic migraine and daily headache had a different response after three sessions of OnabotulinutoxinA than patients without daily headache. The secondary endpoint was to analyse the presence of predictive factors that could be associated with a higher response to OnabotulinumtoxinA. Patients with daily headache had a reduction of 14.9 (SD: 9.7) headache days per month, patients with 22–29 headache days a reduction of 10.6 (SD: 9.9) days, and patients with 15–21 headache days a reduction of 8.6 (SD: 7.1) days (p < 0.001). In the univariate regression analysis, a higher number of headache days per month at baseline was associated with higher odds of reduction in the number of headache days per month after OnabotulinumtoxinaA treatment (OR: 0.474, 95% CI: 0.278–0.670, p < 0.001). This association was maintained in the multivariate regression analysis (OR: 0.540, 95% CI: 0.333–0.746, p < 0.001). In our sample, daily headache was not associated with a worse response to OnabotulinumtoxinA treatment. A higher frequency of headache at baseline was a predictor of better response to OnabotulinumtoxinA treatment. Full article
(This article belongs to the Section Bacterial Toxins)
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Article
The Regulatory Mechanism of Water Activities on Aflatoxins Biosynthesis and Conidia Development, and Transcription Factor AtfB Is Involved in This Regulation
Toxins 2021, 13(6), 431; https://doi.org/10.3390/toxins13060431 - 21 Jun 2021
Viewed by 618
Abstract
Peanuts are frequently infected by Aspergillus strains and then contaminated by aflatoxins (AF), which brings out economic losses and health risks. AF production is affected by diverse environmental factors, especially water activity (aw). In this study, A. flavus was inoculated [...] Read more.
Peanuts are frequently infected by Aspergillus strains and then contaminated by aflatoxins (AF), which brings out economic losses and health risks. AF production is affected by diverse environmental factors, especially water activity (aw). In this study, A. flavus was inoculated into peanuts with different aw (0.90, 0.95, and 0.99). Both AFB1 yield and conidia production showed the highest level in aw 0.90 treatment. Transcriptional level analyses indicated that AF biosynthesis genes, especially the middle- and later-stage genes, were significantly up-regulated in aw 0.90 than aw 0.95 and 0.99. AtfB could be the pivotal regulator response to aw variations, and could further regulate downstream genes, especially AF biosynthesis genes. The expressions of conidia genes and relevant regulators were also more up-regulated at aw 0.90 than aw 0.95 and 0.99, suggesting that the relative lower aw could increase A. flavus conidia development. Furthermore, transcription factors involved in sexual development and nitrogen metabolism were also modulated by different aw. This research partly clarified the regulatory mechanism of aw on AF biosynthesis and A. flavus development and it would supply some advice for AF prevention in food storage. Full article
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Article
Reduction of the Adverse Impacts of Fungal Mycotoxin on Proximate Composition of Feed and Growth Performance in Broilers by Combined Adsorbents
Toxins 2021, 13(6), 430; https://doi.org/10.3390/toxins13060430 - 21 Jun 2021
Viewed by 645
Abstract
Synergistic interaction of adsorbents in reducing the adverse impacts of mycotoxin on performance and proximate composition of broiler feeds was investigated. Fungal growth was induced by sprinkling water on the feed. S. cerevisiae + bentonite, kaolin + bentonite or S. cerevisiea + kaolin [...] Read more.
Synergistic interaction of adsorbents in reducing the adverse impacts of mycotoxin on performance and proximate composition of broiler feeds was investigated. Fungal growth was induced by sprinkling water on the feed. S. cerevisiae + bentonite, kaolin + bentonite or S. cerevisiea + kaolin adsorbent combinations (1.5 g/kg feed) were added and the feeds were stored in black polythene bags. An untreated group was kept as a positive control while fresh uncontaminated feed was used as a negative control. Mycotoxins were extracted from the feeds and quantified using reverse phase HPLC. Proximate composition, nutrient digestibility of the feeds, feed intake and weight gain of the broilers were measured. Deoxynivalenol (DON) concentration in the contaminated/untreated feed was 347 µg/kg while aflatoxin B1 (AFB1) was 34 µg/kg. Addition of bentonite and kaolin in the contaminated feed reduced AFB1 and DON to significantly lower levels. Feed intake and weight gain were low in the broilers fed the contaminated feed. The carbohydrate level was significantly (p < 0.05) reduced from 62.31 to 40.10%, crude protein digestibility dropped from 80.67 to 49.03% in the fresh feed and contaminated feed respectively. Addition of the adsorbents (S. cerevisiae and bentonite) significantly (p < 0.05) improved these parameters. Full article
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Article
Enzymatic Degradation of Multiple Major Mycotoxins by Dye-Decolorizing Peroxidase from Bacillus subtilis
Toxins 2021, 13(6), 429; https://doi.org/10.3390/toxins13060429 - 19 Jun 2021
Viewed by 653
Abstract
The co-occurrence of multiple mycotoxins, including aflatoxin B1 (AFB1), zearalenone (ZEN) and deoxynivalenol (DON), widely exists in cereal-based animal feed and food. At present, most reported mycotoxins degrading enzymes target only a certain type of mycotoxins. Therefore, it is of [...] Read more.
The co-occurrence of multiple mycotoxins, including aflatoxin B1 (AFB1), zearalenone (ZEN) and deoxynivalenol (DON), widely exists in cereal-based animal feed and food. At present, most reported mycotoxins degrading enzymes target only a certain type of mycotoxins. Therefore, it is of great significance for mining enzymes involved in the simultaneous degradation of different types of mycotoxins. In this study, a dye-decolorizing peroxidase-encoding gene BsDyP from Bacillus subtilis SCK6 was cloned and expressed in Escherichia coli BL21/pG-Tf2. The purified recombinant BsDyP was capable of oxidizing various substrates, including lignin phenolic model compounds 2,6-dimethylphenol and guaiacol, the substrate 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid), anthraquinone dye reactive blue 19 and azo dye reactive black 5, as well as Mn2+. In addition, BsDyP could efficiently degrade different types of mycotoxins, including AFB1, ZEN and DON, in presence of Mn2+. More important, the toxicities of their corresponding enzymatic degradation products AFB1-diol, 15-OH-ZEN and C15H18O8 were significantly lower than AFB1, ZEN and DON. In summary, these results proved that BsDyP was a promising candidate for the simultaneous degradation of multiple mycotoxins in animal feed and food. Full article
(This article belongs to the Section Mycotoxins)
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Article
Efficacy and Optimal Dose of Botulinum Toxin A in Post-Stroke Lower Extremity Spasticity: A Systematic Review and Meta-Analysis
Toxins 2021, 13(6), 428; https://doi.org/10.3390/toxins13060428 - 18 Jun 2021
Viewed by 1128
Abstract
Post-stroke spasticity impedes patients’ rehabilitation progress. Contradictory evidence has been reported in using Botulinum Neurotoxin type A (BoNT-A) to manage post-stroke lower extremity spasticity (PLES); furthermore, an optimum dose of BoNT-A for PLES has not yet been established. Therefore, we conducted a systematic [...] Read more.
Post-stroke spasticity impedes patients’ rehabilitation progress. Contradictory evidence has been reported in using Botulinum Neurotoxin type A (BoNT-A) to manage post-stroke lower extremity spasticity (PLES); furthermore, an optimum dose of BoNT-A for PLES has not yet been established. Therefore, we conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to identify the efficacy and optimal dose of BoNT-A on PLES. "Meta" and "Metafor" packages in R were used to analyze the data. Hedges’ g statistic and random effect model were used to calculate and pool effect sizes. Twelve RCTs met the eligibility criteria. Muscle tone significantly improved in week four, week eight, and maintained to week twelve after BoNT-A injection. Improvements in functional outcomes were found, some inconsistencies among included studies were noticed. Dosage analysis from eight studies using Botox® and three studies using Dysport® indicated that the optimum dose for the commonest pattern of PLES (spastic plantar flexors) is medium-dose (approximately 300U Botox® or 1000 U Dysport®). BoNT-A should be regarded as part of a rehabilitation program for PLES. Furthermore, an optimal rehabilitation program combined with BoNT-A management needs to be established. Further studies should also focus on functional improvement by BoNT-A management in the early stage of stroke. Full article
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Review
Old World Vipers—A Review about Snake Venom Proteomics of Viperinae and Their Variations
Toxins 2021, 13(6), 427; https://doi.org/10.3390/toxins13060427 - 17 Jun 2021
Viewed by 1021
Abstract
Fine-tuned by millions of years of evolution, snake venoms have frightened but also fascinated humanity and nowadays they constitute potential resources for drug development, therapeutics and antivenoms. The continuous progress of mass spectrometry techniques and latest advances in proteomics workflows enabled toxinologists to [...] Read more.
Fine-tuned by millions of years of evolution, snake venoms have frightened but also fascinated humanity and nowadays they constitute potential resources for drug development, therapeutics and antivenoms. The continuous progress of mass spectrometry techniques and latest advances in proteomics workflows enabled toxinologists to decipher venoms by modern omics technologies, so-called ‘venomics’. A tremendous upsurge reporting on snake venom proteomes could be observed. Within this review we focus on the highly venomous and widely distributed subfamily of Viperinae (Serpentes: Viperidae). A detailed public literature database search was performed (2003–2020) and we extensively reviewed all compositional venom studies of the so-called Old-World Vipers. In total, 54 studies resulted in 89 venom proteomes. The Viperinae venoms are dominated by four major, four secondary, six minor and several rare toxin families and peptides, respectively. The multitude of different venomics approaches complicates the comparison of venom composition datasets and therefore we differentiated between non-quantitative and three groups of quantitative workflows. The resulting direct comparisons within these groups show remarkable differences on the intra- and interspecies level across genera with a focus on regional differences. In summary, the present compilation is the first comprehensive up-to-date database on Viperinae venom proteomes and differentiating between analytical methods and workflows. Full article
(This article belongs to the Special Issue Evolution, Genomics and Proteomics of Venom)
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Review
Bacterial Toxins Are a Never-Ending Source of Surprises: From Natural Born Killers to Negotiators
Toxins 2021, 13(6), 426; https://doi.org/10.3390/toxins13060426 - 17 Jun 2021
Viewed by 940
Abstract
The idea that bacterial toxins are not only killers but also execute more sophisticated roles during bacteria–host interactions by acting as negotiators has been highlighted in the past decades. Depending on the toxin, its cellular target and mode of action, the final regulatory [...] Read more.
The idea that bacterial toxins are not only killers but also execute more sophisticated roles during bacteria–host interactions by acting as negotiators has been highlighted in the past decades. Depending on the toxin, its cellular target and mode of action, the final regulatory outcome can be different. In this review, we have focused on two families of bacterial toxins: genotoxins and pore-forming toxins, which have different modes of action but share the ability to modulate the host’s immune responses, independently of their capacity to directly kill immune cells. We have addressed their immuno-suppressive effects with the perspective that these may help bacteria to avoid clearance by the host’s immune response and, concomitantly, limit detrimental immunopathology. These are optimal conditions for the establishment of a persistent infection, eventually promoting asymptomatic carriers. This immunomodulatory effect can be achieved with different strategies such as suppression of pro-inflammatory cytokines, re-polarization of the immune response from a pro-inflammatory to a tolerogenic state, and bacterial fitness modulation to favour tissue colonization while preventing bacteraemia. An imbalance in each of those effects can lead to disease due to either uncontrolled bacterial proliferation/invasion, immunopathology, or both. Full article
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Article
Combined Effects of Temperature and Toxic Algal Abundance on Paralytic Shellfish Toxic Accumulation, Tissue Distribution and Elimination Dynamics in Mussels Mytilus coruscus
Toxins 2021, 13(6), 425; https://doi.org/10.3390/toxins13060425 - 17 Jun 2021
Viewed by 659
Abstract
This study assessed the impact of increasing seawater surface temperature (SST) and toxic algal abundance (TAA) on the accumulation, tissue distribution and elimination dynamics of paralytic shellfish toxins (PSTs) in mussels. Mytilus coruscus were fed with the PSTs-producing dinoflagellate A. catenella under four [...] Read more.
This study assessed the impact of increasing seawater surface temperature (SST) and toxic algal abundance (TAA) on the accumulation, tissue distribution and elimination dynamics of paralytic shellfish toxins (PSTs) in mussels. Mytilus coruscus were fed with the PSTs-producing dinoflagellate A. catenella under four simulated environment conditions. The maximum PSTs concentration was determined to be 3548 µg STX eq.kg−1, which was four times higher than the EU regulatory limit. The increasing SST caused a significant decline in PSTs levels in mussels with rapid elimination rates, whereas high TAA increased the PSTs concentration. As a result, the PSTs toxicity levels decreased under the combined condition. Additionally, toxin burdens were assessed within shellfish tissues, with the highest levels quantified in the hepatopancreas. It is noteworthy that the toxin burden shifted towards the mantle from gill, muscle and gonad at the 17th day. Moreover, variability of PSTs was measured, and was associated with changes in each environmental factor. Hence, this study primarily illustrates the combined effects of SST and TAA on PSTs toxicity, showing that increasing environmental temperature is of benefit to lower PSTs toxicity with rapid elimination rates. Full article
(This article belongs to the Section Marine and Freshwater Toxins)
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Article
Tamoxifen Derivatives Alter Retromer-Dependent Endosomal Tubulation and Sorting to Block Retrograde Trafficking of Shiga Toxins
Toxins 2021, 13(6), 424; https://doi.org/10.3390/toxins13060424 - 15 Jun 2021
Viewed by 696
Abstract
Shiga toxin 1 and 2 (STx1 and STx2) undergo retrograde trafficking to reach the cytosol of cells where they target ribosomes. As retrograde trafficking is essential for disease, inhibiting STx1/STx2 trafficking is therapeutically promising. Recently, we discovered that the chemotherapeutic drug tamoxifen potently [...] Read more.
Shiga toxin 1 and 2 (STx1 and STx2) undergo retrograde trafficking to reach the cytosol of cells where they target ribosomes. As retrograde trafficking is essential for disease, inhibiting STx1/STx2 trafficking is therapeutically promising. Recently, we discovered that the chemotherapeutic drug tamoxifen potently inhibits the trafficking of STx1/STx2 at the critical early endosome-to-Golgi step. We further reported that the activity of tamoxifen against STx1/STx2 is independent of its selective estrogen receptor modulator (SERM) property and instead depends on its weakly basic chemical nature, which allows tamoxifen to increase endolysosomal pH and alter the recruitment of retromer to endosomes. The goal of the current work was to obtain a better understanding of the mechanism of action of tamoxifen against the more disease-relevant toxin STx2, and to differentiate between the roles of changes in endolysosomal pH and retromer function. Structure activity relationship (SAR) analyses revealed that a weakly basic amine group was essential for anti-STx2 activity. However, ability to deacidify endolysosomes was not obligatorily necessary because a tamoxifen derivative that did not increase endolysosomal pH exerted reduced, but measurable, activity. Additional assays demonstrated that protective derivatives inhibited the formation of retromer-dependent, Golgi-directed, endosomal tubules, which mediate endosome-to-Golgi transport, and the sorting of STx2 into these tubules. These results identify retromer-mediated endosomal tubulation and sorting to be fundamental processes impacted by tamoxifen; provide an explanation for the inhibitory effect of tamoxifen on STx2; and have important implications for the therapeutic use of tamoxifen, including its development for treating Shiga toxicosis. Full article
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Case Report
Enhanced Effect of Botulinum Toxin A Injections into the Extensor Digitorum Brevis Muscle after Local Mechanical Leg Vibration: A Case Report
Toxins 2021, 13(6), 423; https://doi.org/10.3390/toxins13060423 - 15 Jun 2021
Viewed by 675
Abstract
Background: The aim of this study was to demonstrate an increase in muscle action potentials and an enhancement of the efficacy of botulinum toxin (BoNT) after mechanical leg vibration. Methods: A 53-year-old healthy male volunteer underwent vibration ergometry training (VET) every morning and [...] Read more.
Background: The aim of this study was to demonstrate an increase in muscle action potentials and an enhancement of the efficacy of botulinum toxin (BoNT) after mechanical leg vibration. Methods: A 53-year-old healthy male volunteer underwent vibration ergometry training (VET) every morning and every evening for 10 min for 14 days. Compound muscle action potential (CMAP) of the right (R) and left (L) extensor digitorum brevis (EDB) muscle was analyzed by supramaximal peroneal nerve stimulation before and after VET 12 times during the 14 days. Thereafter, VET was stopped and 20 U incobotulinumtoxin (incoBoNT/A) were injected into the right EDB. During the following 10 days, CMAP of both EDBs was tested 12 times. Results: Under VET, the CMAP of both EDBs significantly increased (L: p < 0.01; R: p < 0.01). During the first 14 days, CMAP of the left EDB before VET was significantly (<0.008) lower than 20 min later after VET. This was not the case for the better trained right EDB. After day 14, CMAP of the untreated left EDB further increased for 6 days and then decreased again. In the right EDB, BoNT-treated EDB CMAP rapidly and highly significantly (p < 0.0001) decreased during the first 48 h by about 90%, from a level of about 14 mV down to a plateau of around 1.5 mV. Conclusion: Local mechanical leg vibration has a short- and long-term training effect. Compared to other studies analyzing the reduction in EDB CMAPs after BoNT injections, the reduction of EDB CMAPs in the present study observed after combined application of BoNT and VET was much faster and more pronounced. Full article
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Article
Combined Effect of Deoxynivalenol (DON) and Porcine Circovirus Type 2 (Pcv2) on Inflammatory Cytokine mRNA Expression
Toxins 2021, 13(6), 422; https://doi.org/10.3390/toxins13060422 - 13 Jun 2021
Viewed by 827
Abstract
A host’s immune system can be invaded by mycotoxin deoxynivalenol (DON) poisoning and porcine circovirus type 2 (PCV2) infections, which affect the host’s natural immune function. Pro-inflammatory cytokines, IL-1β and IL-6, are important regulators in the process of natural immune response, which participate [...] Read more.
A host’s immune system can be invaded by mycotoxin deoxynivalenol (DON) poisoning and porcine circovirus type 2 (PCV2) infections, which affect the host’s natural immune function. Pro-inflammatory cytokines, IL-1β and IL-6, are important regulators in the process of natural immune response, which participate in inflammatory response and enhance immune-mediated tissue damage. Preliminary studies have shown that DON promotes PCV2 infection by activating the MAPK signaling pathway. Here, we explored whether the mRNA expression of IL-1β and IL-6, induced by the combination of DON and PCV2, would depend on the MAPK signaling pathway. Specific pharmacological antagonists U0126, SP600125 and SB203580, were used to inhibit the activities of ERK, JNK and p38 in the MAPK signaling pathway, respectively. Then, the mRNA expression of IL-1β and IL-6 in PK-15 cells was detected to explore the effect of the MAPK signaling pathway on IL-1β and IL-6 mRNA induced by DON and PCV2. The results showed that PK-15 cells treated with DON or PCV2 induced the mRNA expression of IL-1β and IL-6 in a time- and dose-dependent manner. The combination of DON and PCV2 has an additive effect on inducing the mRNA expression of IL-1β and IL-6. Additionally, both DON and PCV2 could induce the mRNA expression of IL-1β and IL-6 via the ERK and the p38 MAPK signal pathways, while PCV2 could induce it via the JNK signal pathway. Taken together, our results suggest that MAPKs play a contributory role in IL-1β and IL-6 mRNA expression when induced by both DON and PCV2. Full article
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Article
Potential Health Risk Associated with Mycotoxins in Oat Grains Consumed in Spain
Toxins 2021, 13(6), 421; https://doi.org/10.3390/toxins13060421 - 13 Jun 2021
Viewed by 796
Abstract
Spain is a relevant producer of oats (Avena sativa), but to date there has been no study on the occurrence/co-occurrence of mycotoxins in oats marketed in Spain. The present study is addressed to overcome this lack of knowledge. One hundred oat [...] Read more.
Spain is a relevant producer of oats (Avena sativa), but to date there has been no study on the occurrence/co-occurrence of mycotoxins in oats marketed in Spain. The present study is addressed to overcome this lack of knowledge. One hundred oat kernel samples were acquired across different Spanish geographic regions during the years 2015–2019 and analyzed for mycotoxin content using an ultra-high performance liquid chromatography electrospray ionization tandem mass spectrometry (UPLC–ESI–MS/MS) method and matrix-matched calibration. The focus was on the regulated mycotoxins although other relevant mycotoxins were considered. The percentage of incidence (levels ≥ limit of detection), mean and range (ng/g) of mycotoxins were as follows: zearalenone (66%, mean 39.1, range 28.1–153), HT-2 toxin (47%, mean 37.1, range 4.98–439), deoxynivalenol, (34%, mean 81.4, range 19.1–736), fumonisin B1 (29%, mean 157.5, range 63.2–217.4), and T-2 toxin, (24%, mean 49.9, range 12.3–321). Fumonisin B2, 3-acetyldeoxynivalenol, aflatoxins B1, B2, and G2, and ochratoxin A were also detected at low levels, but aflatoxin G1 was not. The maximum limits established by the European Commission for unprocessed oats were not exceeded, except for zearalenone (in one sample), and the sum of aflatoxins (in two samples). Mycotoxin co-occurrence at quantifiable levels in the same sample (two to five combinations) was found in 31% of samples. The most common mixtures were those of HT-2 + T-2 toxins alone or together with deoxynivalenol and/or zearalenone. Full article
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Article
A Novel and Efficient High-Yield Method for Preparing Bacterial Ghosts
Toxins 2021, 13(6), 420; https://doi.org/10.3390/toxins13060420 - 13 Jun 2021
Viewed by 777
Abstract
Bacterial ghosts (BGs) are empty cell envelopes possessing native extracellular structures without a cytoplasm and genetic materials. BGs are proposed to have significant prospects in biomedical research as vaccines or delivery carriers. The applications of BGs are often limited by inefficient bacterial lysis [...] Read more.
Bacterial ghosts (BGs) are empty cell envelopes possessing native extracellular structures without a cytoplasm and genetic materials. BGs are proposed to have significant prospects in biomedical research as vaccines or delivery carriers. The applications of BGs are often limited by inefficient bacterial lysis and a low yield. To solve these problems, we compared the lysis efficiency of the wild-type protein E (EW) from phage ΦX174 and the screened mutant protein E (EM) in the Escherichia coli BL21(DE3) strain. The results show that the lysis efficiency mediated by protein EM was improved. The implementation of the pLysS plasmid allowed nearly 100% lysis efficiency, with a high initial cell density as high as OD600 = 2.0, which was higher compared to the commonly used BG preparation method. The results of Western blot analysis and immunofluorescence indicate that the expression level of protein EM was significantly higher than that of the non-pLysS plasmid. High-quality BGs were observed by SEM and TEM. To verify the applicability of this method in other bacteria, the T7 RNA polymerase expression system was successfully constructed in Salmonella enterica (S. Enterica, SE). A pET vector containing EM and pLysS were introduced to obtain high-quality SE ghosts which could provide efficient protection for humans and animals. This paper describes a novel and commonly used method to produce high-quality BGs on a large scale for the first time. Full article
(This article belongs to the Special Issue Bacterial Pore-Forming Toxin)
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Article
Heat-Labile Toxin from Enterotoxigenic Escherichia coli Causes Systemic Impairment in Zebrafish Model
Toxins 2021, 13(6), 419; https://doi.org/10.3390/toxins13060419 - 12 Jun 2021
Viewed by 826
Abstract
Heat-labile toxin I (LT-I), produced by strains of enterotoxigenic Escherichia coli (ETEC), causes profuse watery diarrhea in humans. Different in vitro and in vivo models have already elucidated the mechanism of action of this toxin; however, their use does not always allow for [...] Read more.
Heat-labile toxin I (LT-I), produced by strains of enterotoxigenic Escherichia coli (ETEC), causes profuse watery diarrhea in humans. Different in vitro and in vivo models have already elucidated the mechanism of action of this toxin; however, their use does not always allow for more specific studies on how the LT-I toxin acts in systemic tracts and intestinal cell lines. In the present work, zebrafish (Danio rerio) and human intestinal cells (Caco-2) were used as models to study the toxin LT-I. Caco-2 cells were used, in the 62nd passage, at different cell concentrations. LT-I was conjugated to FITC to visualize its transport in cells, as well as microinjected into the caudal vein of zebrafish larvae, in order to investigate its effects on survival, systemic traffic, and morphological formation. The internalization of LT-I was visualized in 3 × 104 Caco-2 cells, being associated with the cell membrane and nucleus. The systemic traffic of LT-I in zebrafish larvae showed its presence in the cardiac cavity, yolk, and regions of the intestine, as demonstrated by cardiac edema (100%), the absence of a swimming bladder (100%), and yolk edema (80%), in addition to growth limitation in the larvae, compared to the control group. There was a reduction in heart rate during the assessment of larval survival kinetics, demonstrating the cardiotoxic effect of LT-I. Thus, in this study, we provide essential new depictions of the features of LT-I. Full article
(This article belongs to the Special Issue Escherichia coli Toxins and Intestinal Diseases)
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Article
Determination of Urinary Mycotoxin Biomarkers Using a Sensitive Online Solid Phase Extraction-UHPLC-MS/MS Method
Toxins 2021, 13(6), 418; https://doi.org/10.3390/toxins13060418 - 11 Jun 2021
Viewed by 803
Abstract
In the course of assessing the human exposure to mycotoxins, biomarker-based approaches have proven to be important tools. Low concentration levels, complex matrix compositions, structurally diverse analytes, and the large size of sample cohorts are the main challenges of analytical procedures. For that [...] Read more.
In the course of assessing the human exposure to mycotoxins, biomarker-based approaches have proven to be important tools. Low concentration levels, complex matrix compositions, structurally diverse analytes, and the large size of sample cohorts are the main challenges of analytical procedures. For that reason, an online solid phase extraction-ultra high-performance liquid chromatography-tandem mass spectrometry (online SPE-UHPLC-MS/MS) method was developed, allowing for the sensitive, robust, and rapid analysis of 11 relevant mycotoxins and mycotoxin metabolites in human urine. The included spectrum of analytes comprises aflatoxin M1 (AFM1), altenuene (ALT), alternariol monomethyl ether (AME), alternariol (AOH), citrinin (CIT) and its metabolite dihydrocitrinone (DH-CIT), fumonisin B1 (FB1), ochratoxin A (OTA), and zearalenone (ZEN) as well as α- and β-zearalenol (α- and β-ZEL). Reliable quantitation was achieved by means of stable isotope dilution, except for ALT, AME and AOH using matrix calibrations. The evaluation of method performance displayed low limits of detection in the range of pg/mL urine, satisfactory apparent recovery rates as well as high accuracy and precision during intra- and interday repeatability. Within the analysis of Zimbabwean urine samples (n = 50), the applicability of the newly developed method was shown. In addition to FB1 being quantifiable in all analyzed samples, six other mycotoxin biomarkers were detected. Compared to the occurrence rates obtained after analyzing the same sample set using an established dilute and shoot (DaS) approach, a considerably higher number of positive samples was observed when applying the online SPE method. Owing to the increased sensitivity, less need of sample handling, and low time effort, the herein presented online SPE approach provides a valuable contribution to human biomonitoring of mycotoxin exposure. Full article
(This article belongs to the Special Issue Biomonitoring of Mycotoxins)
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Review
Toxic Effects of Amanitins: Repurposing Toxicities toward New Therapeutics
Toxins 2021, 13(6), 417; https://doi.org/10.3390/toxins13060417 - 11 Jun 2021
Cited by 1 | Viewed by 755
Abstract
The consumption of mushrooms has become increasingly popular, partly due to their nutritional and medicinal properties. This has increased the risk of confusion during picking, and thus of intoxication. In France, about 1300 cases of intoxication are observed each year, with deaths being [...] Read more.
The consumption of mushrooms has become increasingly popular, partly due to their nutritional and medicinal properties. This has increased the risk of confusion during picking, and thus of intoxication. In France, about 1300 cases of intoxication are observed each year, with deaths being mostly attributed to Amanita phalloides poisoning. Among amatoxins, α- and β-amanitins are the most widely studied toxins. Hepatotoxicity is the hallmark of these compounds, leading to hepatocellular failure within three days of ingestion. The toxic mechanisms of action mainly include RNA polymerase II inhibition and oxidative stress generation, leading to hepatic cell apoptosis or necrosis depending on the doses ingested. Currently, there is no international consensus concerning Amanita phalloides poisoning management. However, antidotes with antioxidant properties remain the most effective therapeutics to date suggesting the predominant role of oxidative stress in the pathophysiology. The partially elucidated mechanisms of action may reveal a suitable target for the development of an antidote. The aim of this review is to present an overview of the knowledge on amanitins, including the latest advances that could allow the proposal of new innovative and effective therapeutics. Full article
(This article belongs to the Special Issue Toxic Effect of Mycotoxins)
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Review
Escherichia coli Shiga Toxins and Gut Microbiota Interactions
Toxins 2021, 13(6), 416; https://doi.org/10.3390/toxins13060416 - 11 Jun 2021
Viewed by 933
Abstract
Escherichia coli (EHEC) and Shigella dysenteriae serotype 1 are enterohemorrhagic bacteria that induce hemorrhagic colitis. This, in turn, may result in potentially lethal complications, such as hemolytic uremic syndrome (HUS), which is characterized by thrombocytopenia, acute renal failure, and neurological abnormalities. Both species [...] Read more.
Escherichia coli (EHEC) and Shigella dysenteriae serotype 1 are enterohemorrhagic bacteria that induce hemorrhagic colitis. This, in turn, may result in potentially lethal complications, such as hemolytic uremic syndrome (HUS), which is characterized by thrombocytopenia, acute renal failure, and neurological abnormalities. Both species of bacteria produce Shiga toxins (Stxs), a phage-encoded exotoxin inhibiting protein synthesis in host cells that are primarily responsible for bacterial virulence. Although most studies have focused on the pathogenic roles of Stxs as harmful substances capable of inducing cell death and as proinflammatory factors that sensitize the host target organs to damage, less is known about the interface between the commensalism of bacterial communities and the pathogenicity of the toxins. The gut contains more species of bacteria than any other organ, providing pathogenic bacteria that colonize the gut with a greater number of opportunities to encounter other bacterial species. Notably, the presence in the intestines of pathogenic EHEC producing Stxs associated with severe illness may have compounding effects on the diversity of the indigenous bacteria and bacterial communities in the gut. The present review focuses on studies describing the roles of Stxs in the complex interactions between pathogenic Shiga toxin-producing E. coli, the resident microbiome, and host tissues. The determination of these interactions may provide insights into the unresolved issues regarding these pathogens. Full article
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Editorial
Animal Venoms and Their Components: Molecular Mechanisms of Action
Toxins 2021, 13(6), 415; https://doi.org/10.3390/toxins13060415 - 11 Jun 2021
Viewed by 762
Abstract
Animal venoms comprise numerous toxin families, consisting mainly of peptides and proteins [...] Full article
(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)
Editorial
Drug Development Using Natural Toxins
Toxins 2021, 13(6), 414; https://doi.org/10.3390/toxins13060414 - 11 Jun 2021
Viewed by 772
Abstract
Natural toxins are poisonous substances produced by bacteria, insects, animals, or plants [...] Full article
(This article belongs to the Special Issue Drug Development Using Natural Toxins)
Article
Asynchrony of Gambierdiscus spp. Abundance and Toxicity in the U.S. Virgin Islands: Implications for Monitoring and Management of Ciguatera
Toxins 2021, 13(6), 413; https://doi.org/10.3390/toxins13060413 - 10 Jun 2021
Cited by 1 | Viewed by 772
Abstract
Ciguatera poisoning (CP) poses a significant threat to ecosystem services and fishery resources in coastal communities. The CP-causative ciguatoxins (CTXs) are produced by benthic dinoflagellates including Gambierdiscus and Fukuyoa spp., and enter reef food webs via grazing on macroalgal substrates. In this study, [...] Read more.
Ciguatera poisoning (CP) poses a significant threat to ecosystem services and fishery resources in coastal communities. The CP-causative ciguatoxins (CTXs) are produced by benthic dinoflagellates including Gambierdiscus and Fukuyoa spp., and enter reef food webs via grazing on macroalgal substrates. In this study, we report on a 3-year monthly time series in St. Thomas, US Virgin Islands where Gambierdiscus spp. abundance and Caribbean-CTX toxicity in benthic samples were compared to key environmental factors, including temperature, salinity, nutrients, benthic cover, and physical data. We found that peak Gambierdiscus abundance occurred in summer while CTX-specific toxicity peaked in cooler months (February–May) when the mean water temperatures were approximately 26–28 °C. These trends were most evident at deeper offshore sites where macroalgal cover was highest year-round. Other environmental parameters were not correlated with the CTX variability observed over time. The asynchrony between Gambierdiscus spp. abundance and toxicity reflects potential differences in toxin cell quotas among Gambierdiscus species with concomitant variability in their abundances throughout the year. These results have significant implications for monitoring and management of benthic harmful algal blooms and highlights potential seasonal and highly-localized pulses in reef toxin loads that may be transferred to higher trophic levels. Full article
(This article belongs to the Special Issue Ciguatoxins)
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Article
Bio-Preservative Potential of Microorganisms Isolated from Red Grape against Food Contaminant Fungi
Toxins 2021, 13(6), 412; https://doi.org/10.3390/toxins13060412 - 10 Jun 2021
Viewed by 854
Abstract
Fungal spoilage is one of the main reasons of economic losses in the food industry, especially in the wine sector. Consequently, the search for safer and new preservation techniques has gained importance in recent years. The objective of this study was to investigate [...] Read more.
Fungal spoilage is one of the main reasons of economic losses in the food industry, especially in the wine sector. Consequently, the search for safer and new preservation techniques has gained importance in recent years. The objective of this study was to investigate the antifungal and anti-mycotoxigenic activity from 28 microorganisms (MO) isolated from red grape. The antifungal activity of a cell free supernatant of fermented medium by the isolated MO (CFS) was tested with the agar diffusion method and the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) assay. Additionally, different antifungal compounds from the CFS were identified and quantified (organic acids, phenolic compounds, and volatile organic compounds). Finally, the most active CFS were tested as red grape bio-preservative agents. Results evidenced that CFS fermented by the strain UTA 6 had the highest antifungal activity, above all isolates, and produced a wide pool of antifungal compounds. The use of UTA 6 CFS as bio-preservative agent showed a reduction of 0.4 and 0.6 log10 spores per gram of fruit in grapes contaminated by A. flavus and B. cinerea, respectively. Moreover, UTA 6 CFS treatment reduced the occurrence of aflatoxin B1 and fumonisin (B2, B3, and B4) production in grapes contaminated by 28–100%. Full article
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Communication
Field Experiment Effect on Citrus Spider Mite Panonychus citri of Venom from Jellyfish Nemopilema nomurai: The Potential Use of Jellyfish in Agriculture
Toxins 2021, 13(6), 411; https://doi.org/10.3390/toxins13060411 - 10 Jun 2021
Viewed by 743
Abstract
Jellyfish are rich in resources and widely distributed along coastal areas. As a potential approach to respond to jellyfish blooms, the use of jellyfish-derived products is increasing. The citrus spider mite (Panonychus citri) is one of the key citrus pests, negatively [...] Read more.
Jellyfish are rich in resources and widely distributed along coastal areas. As a potential approach to respond to jellyfish blooms, the use of jellyfish-derived products is increasing. The citrus spider mite (Panonychus citri) is one of the key citrus pests, negatively impacting the quality and quantity of oranges. Due to the resistance and residue of chemical acaricides, it is important to seek natural substitutes that are environmentally friendly. The field efficacy of the venom from the jellyfish Nemopilema nomurai against P. citri was assayed in a citrus garden. The frozen N. nomurai tentacles were sonicated in different buffers to isolate the venom. The venom isolated by PBS buffer (10 mM, pH 6.0) had the strongest acaricidal activity of the four samples, and the corrected field efficacy 7 days after treatment was up to 95.21%. This study demonstrated that jellyfish has potential use in agriculture. Full article
(This article belongs to the Special Issue Cnidarian Venom)
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Communication
The First Data on the Complete Genome of a Tetrodotoxin-Producing Bacterium
Toxins 2021, 13(6), 410; https://doi.org/10.3390/toxins13060410 - 09 Jun 2021
Viewed by 856
Abstract
Tetrodotoxin (TTX)-producing bacteria have attracted great interest as a model system for study of the TTX biosynthetic route. Here, we report the complete genome of the TTX-producing bacterium Bacillus sp. 1839. The genome of the strain Bacillus sp. 1839, previously isolated from the [...] Read more.
Tetrodotoxin (TTX)-producing bacteria have attracted great interest as a model system for study of the TTX biosynthetic route. Here, we report the complete genome of the TTX-producing bacterium Bacillus sp. 1839. The genome of the strain Bacillus sp. 1839, previously isolated from the TTX-bearing marine ribbon worm Cephalothrix cf. simula, was obtained using second generation Illumina and third generation nanopore sequencing technologies. Phylogenetic analysis has classified this strain as Cytobacillus gottheilii. Full article
(This article belongs to the Special Issue Analysis and Evaluation of Tetrodotoxin)
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Article
The Presence of Mycotoxins in Human Amniotic Fluid
Toxins 2021, 13(6), 409; https://doi.org/10.3390/toxins13060409 - 09 Jun 2021
Viewed by 795
Abstract
Mycotoxin exposure assessments through biomonitoring studies, based on the analysis of amniotic fluid, provides useful information about potential exposure of mothers and fetuses to ubiquitous toxic metabolites that are routinely found in food and the environment. In this study, amniotic fluid samples (n [...] Read more.
Mycotoxin exposure assessments through biomonitoring studies, based on the analysis of amniotic fluid, provides useful information about potential exposure of mothers and fetuses to ubiquitous toxic metabolites that are routinely found in food and the environment. In this study, amniotic fluid samples (n = 86) were collected via abdominal amniocentesis at 15–22 weeks of gestation from pregnant women with a high risk of chromosomal anomalies or genetic fetal defects detected during 1st trimester prenatal screening. These samples were analyzed for the presence of the most typical Aspergillus, Penicillium and Fusarium mycotoxins, with a focus on aflatoxins, ochratoxins and trichothecenes, using the LC-FLD/DAD method. The results showed that the toxin was present in over 75% of all the tested samples and in 73% of amniotic fluid samples from fetuses with genetic defects. The most frequently identified toxins were nivalenol (33.7%) ranging from <LOQ to 4037.6 ng/mL, and aflatoxins (31.4%), including aflatoxin G1, ranging from <LOQ to 0.4 ng/mL. Ochratoxin A and deoxynivalenol were identified in 26.7% and 27.9% of samples, respectively. Bearing in mind the above, the detection of mycotoxin levels in amniotic fluid is useful for the estimation of overall risk characterization with an attempt to link the occurrence of fetal abnormalities with exposure to mycotoxins in utero. Full article
(This article belongs to the Section Mycotoxins)
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Article
First Report of Domoic Acid Production from Pseudo-nitzschia multistriata in Paracas Bay (Peru)
Toxins 2021, 13(6), 408; https://doi.org/10.3390/toxins13060408 - 09 Jun 2021
Viewed by 797
Abstract
The Peruvian sea is one of the most productive ecosystems in the world. Phytoplankton production provides food for fish, mammals, mollusks and birds. This trophic network is affected by the presence of toxic phytoplankton species. In July 2017, samples of phytoplankton were obtained [...] Read more.
The Peruvian sea is one of the most productive ecosystems in the world. Phytoplankton production provides food for fish, mammals, mollusks and birds. This trophic network is affected by the presence of toxic phytoplankton species. In July 2017, samples of phytoplankton were obtained from Paracas Bay, an important zone for scallop (Argopecten purpuratus) aquaculture in Peru. Morphological analysis revealed the presence of the genus Pseudo-nitzschia, which was isolated and cultivated in laboratory conditions. Subsequently, the monoclonal cultures were observed by scanning electron microscopy (SEM), and identified as P. multistriata, based on both the morphological characteristics, and internal transcribed spacers region (ITS2) sequence phylogenetic analysis. Toxin analysis using liquid chromatography (LC) with high-resolution mass spectrometry (HRMS) revealed the presence of domoic acid (DA) with an estimated amount of 0.004 to 0.010 pg cell−1. This is the first report of DA from the coastal waters of Peru and its detection in P. multistriata indicates that it is a potential risk. Based on our results, routine monitoring of this genus should be considered in order to ensure public health. Full article
(This article belongs to the Special Issue Marine Toxins from Harmful Algae and Seafood Safety)
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Article
Colombian Scorpion Centruroides margaritatus: Purification and Characterization of a Gamma Potassium Toxin with Full-Block Activity on the hERG1 Channel
Toxins 2021, 13(6), 407; https://doi.org/10.3390/toxins13060407 - 08 Jun 2021
Viewed by 1157
Abstract
The Colombian scorpion Centruroides margaritatus produces a venom considered of low toxicity. Nevertheless, there are known cases of envenomation resulting in cardiovascular disorders, probably due to venom components that target ion channels. Among them, the humanether-à-go-go-Related gene (hERG1) potassium channels are critical [...] Read more.
The Colombian scorpion Centruroides margaritatus produces a venom considered of low toxicity. Nevertheless, there are known cases of envenomation resulting in cardiovascular disorders, probably due to venom components that target ion channels. Among them, the humanether-à-go-go-Related gene (hERG1) potassium channels are critical for cardiac action potential repolarization and alteration in its functionality are associated with cardiac disorders. This work describes the purification and electrophysiological characterization of a Centruroides margaritatus venom component acting on hERG1 channels, the CmERG1 toxin. This novel peptide is composed of 42 amino acids with a MW of 4792.88 Da, folded by four disulfide bonds and it is classified as member number 10 of the γ-KTx1 toxin family. CmERG1 inhibits hERG1 currents with an IC50 of 3.4 ± 0.2 nM. Despite its 90.5% identity with toxin ɣ-KTx1.1, isolated from Centruroides noxius, CmERG1 completely blocks hERG1 current, suggesting a more stable plug of the hERG channel, compared to that formed by other ɣ-KTx. Full article
(This article belongs to the Section Animal Venoms)
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Article
Ecophysiological Aspects and sxt Genes Expression Underlying Induced Chemical Defense in STX-Producing Raphidiopsis raciborskii (Cyanobacteria) against the Zooplankter Daphnia gessneri
Toxins 2021, 13(6), 406; https://doi.org/10.3390/toxins13060406 - 08 Jun 2021
Viewed by 1191
Abstract
Cyanobacteria stand out among phytoplankton when they form massive blooms and produce toxins. Because cyanotoxin genes date to the origin of metazoans, the hypothesis that cyanotoxins function as a defense against herbivory is still debated. Although their primary cellular function might vary, these [...] Read more.
Cyanobacteria stand out among phytoplankton when they form massive blooms and produce toxins. Because cyanotoxin genes date to the origin of metazoans, the hypothesis that cyanotoxins function as a defense against herbivory is still debated. Although their primary cellular function might vary, these metabolites could have evolved as an anti-predator response. Here we evaluated the physiological and molecular responses of a saxitoxin-producing Raphidiopsis raciborskii to infochemicals released by the grazer Daphnia gessneri. Induced chemical defenses were evidenced in R. raciborskii as a significant increase in the transcription level of sxt genes, followed by an increase in saxitoxin content when exposed to predator cues. Moreover, cyanobacterial growth decreased, and no significant effects on photosynthesis or morphology were observed. Overall, the induced defense response was accompanied by a trade-off between toxin production and growth. These results shed light on the mechanisms underlying zooplankton–cyanobacteria interactions in aquatic food webs. The widespread occurrence of the cyanobacterium R. raciborskii in freshwater bodies has been attributed to its phenotypic plasticity. Assessing the potential of this species to thrive over interaction filters such as zooplankton grazing pressure can enhance our understanding of its adaptive success. Full article
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Article
‘Floc and Sink’ Technique Removes Cyanobacteria and Microcystins from Tropical Reservoir Water
Toxins 2021, 13(6), 405; https://doi.org/10.3390/toxins13060405 - 08 Jun 2021
Viewed by 937
Abstract
Combining coagulants with ballast (natural soil or modified clay) to remove cyanobacteria from the water column is a promising tool to mitigate nuisance blooms. Nevertheless, the possible effects of this technique on different toxin-producing cyanobacteria species have not been thoroughly investigated. This laboratory [...] Read more.
Combining coagulants with ballast (natural soil or modified clay) to remove cyanobacteria from the water column is a promising tool to mitigate nuisance blooms. Nevertheless, the possible effects of this technique on different toxin-producing cyanobacteria species have not been thoroughly investigated. This laboratory study evaluated the potential effects of the “Floc and Sink” technique on releasing microcystins (MC) from the precipitated biomass. A combined treatment of polyaluminium chloride (PAC) with lanthanum modified bentonite (LMB) and/or local red soil (LRS) was applied to the bloom material (mainly Dolichospermum circinalis and Microcystis aeruginosa) of a tropical reservoir. Intra and extracellular MC and biomass removal were evaluated. PAC alone was not efficient to remove the biomass, while PAC + LMB + LRS was the most efficient and removed 4.3–7.5 times more biomass than other treatments. Intracellular MC concentrations ranged between 12 and 2.180 µg L−1 independent from the biomass. PAC treatment increased extracellular MC concentrations from 3.5 to 6 times. However, when combined with ballast, extracellular MC was up to 4.2 times lower in the top of the test tubes. Nevertheless, PAC + LRS and PAC + LMB + LRS treatments showed extracellular MC concentration eight times higher than controls in the bottom. Our results showed that Floc and Sink appears to be more promising in removing cyanobacteria and extracellular MC from the water column than a sole coagulant (PAC). Full article
(This article belongs to the Special Issue Removal of Cyanobacteria and Cyanotoxins in Waters)
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Article
Tea: Transfer of Mycotoxins from the Spiked Matrix into an Infusion
Toxins 2021, 13(6), 404; https://doi.org/10.3390/toxins13060404 - 07 Jun 2021
Viewed by 816
Abstract
Recent surveys report the occurrence of Aspergillus and Penicillium metabolites (aflatoxins (AFLs), ochratoxin A (OTA), cyclopiazonic and mycophenolic acids (MPA), sterigmatocystin (STC), citrinin), Fusarium (trichothecenes, zearalenone (ZEA), fumonisins (FBs), enniatins (ENNs)) and Alternaria (alternariol (AOH), its methyl ether (AME), tentoxin (TE), and tenuazonic [...] Read more.
Recent surveys report the occurrence of Aspergillus and Penicillium metabolites (aflatoxins (AFLs), ochratoxin A (OTA), cyclopiazonic and mycophenolic acids (MPA), sterigmatocystin (STC), citrinin), Fusarium (trichothecenes, zearalenone (ZEA), fumonisins (FBs), enniatins (ENNs)) and Alternaria (alternariol (AOH), its methyl ether (AME), tentoxin (TE), and tenuazonic acid (TNZ)) toxins in dry Camellia sinensis and herbal tea samples. Since tea is consumed in the form of infusion, correct risk assessment needs evaluation of mycotoxins’ transfer rates. We have studied the transfer of AFLs, OTA, STC, deoxynivalenol (DON), ZEA, FBs, T-2, and HT-2 toxins, AOH, AME, TE, ENN A and B, beauvericin (BEA), and MPA from the spiked green tea matrix into an infusion under variation of preparation time and water characteristics (total dissolved solids (TDS) and pH). Analytes were detected by HPLC-MS/MS. The main factors affecting transfer rate proved to be mycotoxins’ polarity, pH of the resulting infusion (for OTA, FB2, and MPA) and matrix-infusion contact period. The concentration of mycotoxins increased by 20–50% within the first ten minutes of infusing, after that kinetic curve changed slowly. The concentration of DON and FB2 increased by about 10%, for ZEA, MPA, and STC it stayed constant, while for T-2, TE, AOH, and AFLs G1 and G2 it went down. Maximum transfer correlated well with analytes polarity. Maximum transfer of ENNs, BEA, STC, ZEA, and AOH into infusion was below 25%; AFLs—25–45%; DON, TE, and T-2 toxins 60–90%, FB1—80–100%. The concentration of OTA, MPA, and FB2 in the infusion depended on its pH. At pH about four, 20%, 40%, and 60% of these toxins transferred into an infusion, at pH about seven, their concentrations doubled. Water TDS did not affect transfer significantly. Full article
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Review
The Occurrence of Mycotoxins in Raw Materials and Fish Feeds in Europe and the Potential Effects of Deoxynivalenol (DON) on the Health and Growth of Farmed Fish Species—A Review
Toxins 2021, 13(6), 403; https://doi.org/10.3390/toxins13060403 - 05 Jun 2021
Viewed by 1392
Abstract
The first part of this study evaluates the occurrence of mycotoxin patterns in feedstuffs and fish feeds. Results were extrapolated from a large data pool derived from wheat (n = 857), corn (n = 725), soybean meal (n = 139) [...] Read more.
The first part of this study evaluates the occurrence of mycotoxin patterns in feedstuffs and fish feeds. Results were extrapolated from a large data pool derived from wheat (n = 857), corn (n = 725), soybean meal (n = 139) and fish feed (n = 44) samples in European countries and based on sample analyses by liquid chromatography/tandem mass spectrometry (LC-MS/MS) in the period between 2012–2019. Deoxynivalenol (DON) was readily present in corn (in 47% of the samples) > wheat (41%) > soybean meal (11%), and in aquafeeds (48%). Co-occurrence of mycotoxins was frequently observed in feedstuffs and aquafeed samples. For example, in corn, multi-mycotoxin occurrence was investigated by Spearman’s correlations and odd ratios, and both showed co-occurrence of DON with its acetylated forms (3-AcDON, 15-AcDON) as well as with zearalenone (ZEN). The second part of this study summarizes the existing knowledge on the effects of DON on farmed fish species and evaluates the risk of DON exposure in fish, based on data from in vivo studies. A meta-analytical approach aimed to estimate to which extent DON affects feed intake and growth performance in fish. Corn was identified as the ingredient with the highest risk of contamination with DON and its acetylated forms, which often cannot be detected by commonly used rapid detection methods in feed mills. Periodical state-of-the-art mycotoxin analyses are essential to detect the full spectrum of mycotoxins in fish feeds aimed to prevent detrimental effects on farmed fish and subsequent economic losses for fish farmers. Because levels below the stated regulatory limits can reduce feed intake and growth performance, our results show that the risk of DON contamination is underestimated in the aquaculture industry. Full article
(This article belongs to the Special Issue Mycotoxins in Feeds and Their Effects on Fish)
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