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Toxins, Volume 7, Issue 8 (August 2015), Pages 2701-3371

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Open AccessArticle Molecular Cloning and Functional Analysis of Gene Clusters for the Biosynthesis of Indole-Diterpenes in Penicillium crustosum and P. janthinellum
Toxins 2015, 7(8), 2701-2722; doi:10.3390/toxins7082701
Received: 19 May 2015 / Revised: 22 June 2015 / Accepted: 2 July 2015 / Published: 23 July 2015
Cited by 5 | PDF Full-text (1347 KB) | HTML Full-text | XML Full-text
Abstract
The penitremane and janthitremane families of indole-diterpenes are abundant natural products synthesized by Penicillium crustosum and P. janthinellum. Using a combination of PCR, cosmid library screening, and Illumina sequencing we have identified gene clusters encoding enzymes for the synthesis of these compounds.
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The penitremane and janthitremane families of indole-diterpenes are abundant natural products synthesized by Penicillium crustosum and P. janthinellum. Using a combination of PCR, cosmid library screening, and Illumina sequencing we have identified gene clusters encoding enzymes for the synthesis of these compounds. Targeted deletion of penP in P. crustosum abolished the synthesis of penitrems A, B, D, E, and F, and led to accumulation of paspaline, a key intermediate for paxilline biosynthesis in P. paxilli. Similarly, deletion of janP and janD in P. janthinellum abolished the synthesis of prenyl-elaborated indole-diterpenes, and led to accumulation in the latter of 13-desoxypaxilline, a key intermediate for the synthesis of the structurally related aflatremanes synthesized by Aspergillus flavus. This study helps resolve the genetic basis for the complexity of indole-diterpene natural products found within the Penicillium and Aspergillus species. All indole-diterpene gene clusters identified to date have a core set of genes for the synthesis of paspaline and a suite of genes encoding multi-functional cytochrome P450 monooxygenases, FAD dependent monooxygenases, and prenyl transferases that catalyse various regio- and stereo- specific oxidations that give rise to the diversity of indole-diterpene products synthesized by this group of fungi. Full article
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Open AccessArticle Functional Characterization of New Polyketide Synthase Genes Involved in Ochratoxin A Biosynthesis in Aspergillus Ochraceus fc-1
Toxins 2015, 7(8), 2723-2738; doi:10.3390/toxins7082723
Received: 26 June 2015 / Revised: 10 July 2015 / Accepted: 17 July 2015 / Published: 24 July 2015
Cited by 5 | PDF Full-text (2618 KB) | HTML Full-text | XML Full-text
Abstract
Ochratoxin A (OTA), a potentially carcinogenic mycotoxin which contaminates grains, is produced by several Aspergillus species. A comparative sequence analysis of the OTA-producing Aspergillus ochraceus fc-1 strain and other Aspergillus species was performed. Two new OTA-related polyketide synthase (PKS) (AoOTApks) genes
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Ochratoxin A (OTA), a potentially carcinogenic mycotoxin which contaminates grains, is produced by several Aspergillus species. A comparative sequence analysis of the OTA-producing Aspergillus ochraceus fc-1 strain and other Aspergillus species was performed. Two new OTA-related polyketide synthase (PKS) (AoOTApks) genes were identified. The predicted amino acid sequence of AoOTApks-1 displayed high similarity to previously identified PKSs from OTA-producing A. carbonarius ITEM 5010 (67%; [PI] No. 173482) and A. niger CBS 513.88 (62%; XP_001397313). However, the predicted amino acid sequence of AoOTApks-2 displayed lower homology with A. niger CBS 513.88 (38%) and A. carbonarius ITEM 5010 (28%). A phylogenetic analysis of the β-ketosynthase and acyl-transferase domains of the AoOTApks proteins indicated that they shared a common origin with other OTA-producing species, such as A. carbonarius, A. niger, and A. westerdijkiae. A real-time reverse-transcription PCR analysis showed that the expression of AoOTApks-1 and -2 was positively correlated with the OTA concentration. The pks gene deleted mutants ∆AoOTApks-1 and ∆AoOTApks-2 produced nil and lesser OTA than the wild-type strain, respectively. Our study suggests that AoOTApks-1 could be involved in OTA biosynthesis, while AoOTApks-2 might be indirectly involved in OTA production. Full article
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Open AccessArticle Acetylcholinesterase in Biofouling Species: Characterization and Mode of Action of Cyanobacteria-Derived Antifouling Agents
Toxins 2015, 7(8), 2739-2756; doi:10.3390/toxins7082739
Received: 3 June 2015 / Revised: 5 July 2015 / Accepted: 20 July 2015 / Published: 24 July 2015
Cited by 1 | PDF Full-text (809 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Effective and ecofriendly antifouling (AF) compounds have been arising from naturally produced chemicals. The objective of this study is to use cyanobacteria-derived agents to investigate the role of acetylcholinesterase (AChE) activity as an effect and/or mode of action of promising AF compounds, since
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Effective and ecofriendly antifouling (AF) compounds have been arising from naturally produced chemicals. The objective of this study is to use cyanobacteria-derived agents to investigate the role of acetylcholinesterase (AChE) activity as an effect and/or mode of action of promising AF compounds, since AChE inhibitors were found to inhibit invertebrate larval settlement. To pursue this objective, in vitro quantification of AChE activity under the effect of several cyanobacterial strain extracts as potential AF agents was performed along with in vivo AF (anti-settlement) screening tests. Pre-characterization of different cholinesterases (ChEs) forms present in selected tissues of important biofouling species was performed to confirm the predominance of AChE, and an in vitro AF test using pure AChE activity was developed. Eighteen cyanobacteria strains were tested as source of potential AF and AChE inhibitor agents. Results showed effectiveness in selecting promising eco-friendly AF agents, allowing the understanding of the AF biochemical mode of action induced by different compounds. This study also highlights the potential of cyanobacteria as source of AF agents towards invertebrate macrofouling species. Full article
(This article belongs to the Special Issue Bioactivity and Toxicity in Marine Cyanobacteria)
Open AccessArticle Deoxynivalenol & Deoxynivalenol-3-Glucoside Mitigation through Bakery Production Strategies: Effective Experimental Design within Industrial Rusk-Making Technology
Toxins 2015, 7(8), 2773-2790; doi:10.3390/toxins7082773
Received: 22 April 2015 / Revised: 20 July 2015 / Accepted: 21 July 2015 / Published: 24 July 2015
Cited by 10 | PDF Full-text (724 KB) | HTML Full-text | XML Full-text
Abstract
In the scientific field, there is a progressive awareness about the potential implications of food processing on mycotoxins especially concerning thermal treatments. High temperatures may cause, in fact, transformation or degradation of these compounds. This work is aimed to study the fate of
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In the scientific field, there is a progressive awareness about the potential implications of food processing on mycotoxins especially concerning thermal treatments. High temperatures may cause, in fact, transformation or degradation of these compounds. This work is aimed to study the fate of mycotoxins during bakery processing, focusing on deoxynivalenol (DON) and deoxynivalenol-3-glucoside (DON3Glc), along the chain of industrial rusk production. Starting from naturally contaminated bran, we studied how concentrations of DON and DON3Glc are influenced by modifying ingredients and operative conditions. The experiments were performed using statistical Design of Experiment (DoE) schemes to synergistically explore the relationship between mycotoxin reduction and the indicated processing transformation parameters. All samples collected during pilot plant experiments were analyzed with an LC-MS/MS multimycotoxin method. The obtained model shows a good fitting, giving back relevant information in terms of optimization of the industrial production process, in particular suggesting that time and temperature in baking and toasting steps are highly relevant for minimizing mycotoxin level in rusks. A reduction up to 30% for DON and DON3Glc content in the finished product was observed within an acceptable technological range. Full article
(This article belongs to the collection Understanding Mycotoxin Occurrence in Food and Feed Chains)
Open AccessArticle Induction of Suicidal Erythrocyte Death by Cantharidin
Toxins 2015, 7(8), 2822-2834; doi:10.3390/toxins7082822
Received: 18 May 2015 / Revised: 15 July 2015 / Accepted: 22 July 2015 / Published: 28 July 2015
Cited by 5 | PDF Full-text (795 KB) | HTML Full-text | XML Full-text
Abstract
The natural phosphoprotein phosphatase inhibitor cantharidin, primarily used for topical treatment of warts, has later been shown to trigger tumor cell apoptosis and is thus considered for the treatment of malignancy. Similar to apoptosis of tumor cells, erythrocytes may undergo eryptosis, a suicidal
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The natural phosphoprotein phosphatase inhibitor cantharidin, primarily used for topical treatment of warts, has later been shown to trigger tumor cell apoptosis and is thus considered for the treatment of malignancy. Similar to apoptosis of tumor cells, erythrocytes may undergo eryptosis, a suicidal cell death characterized by cell shrinkage and translocation of cell membrane phosphatidylserine to the erythrocyte surface. Signaling of eryptosis includes increase of cytosolic Ca2+-activity ([Ca2+]i), ceramide, oxidative stress and dysregulation of several kinases. Phosphatidylserine abundance at the erythrocyte surface was quantified utilizing annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, ceramide from antibody binding, and reactive oxidant species (ROS) from 2′,7′-dichlorodihydrofluorescein diacetate (DCFDA) fluorescence. A 48 h treatment of human erythrocytes with cantharidin significantly increased the percentage of annexin-V-binding cells (≥10 mg/mL), significantly decreased forward scatter (≥25 mg/mL), significantly increased [Ca2+]i (≥25 mg/mL), but did not significantly modify ceramide abundance or ROS. The up-regulation of annexin-V-binding following cantharidin treatment was not significantly blunted by removal of extracellular Ca2+ but was abolished by kinase inhibitor staurosporine (1 mM) and slightly decreased by p38 inhibitor skepinone (2 mM). Exposure of erythrocytes to cantharidin triggers suicidal erythrocyte death with erythrocyte shrinkage and erythrocyte membrane scrambling, an effect sensitive to kinase inhibitors staurosporine and skepinone. Full article
Open AccessArticle Bee Venom Acupuncture Augments Anti-Inflammation in the Peripheral Organs of hSOD1G93A Transgenic Mice
Toxins 2015, 7(8), 2835-2844; doi:10.3390/toxins7082835
Received: 24 February 2015 / Accepted: 6 July 2015 / Published: 29 July 2015
Cited by 6 | PDF Full-text (1642 KB) | HTML Full-text | XML Full-text
Abstract
Amyotrophic lateral sclerosis (ALS) includes progressively degenerated motor neurons in the brainstem, motor cortex, and spinal cord. Recent reports demonstrate the dysfunction of multiple organs, including the lungs, spleen, and liver, in ALS animals and patients. Bee venom acupuncture (BVA) has been used
[...] Read more.
Amyotrophic lateral sclerosis (ALS) includes progressively degenerated motor neurons in the brainstem, motor cortex, and spinal cord. Recent reports demonstrate the dysfunction of multiple organs, including the lungs, spleen, and liver, in ALS animals and patients. Bee venom acupuncture (BVA) has been used for treating inflammatory diseases in Oriental Medicine. In a previous study, we demonstrated that BV prevented motor neuron death and increased anti-inflammation in the spinal cord of symptomatic hSOD1G93A transgenic mice. In this study, we examined whether BVA’s effects depend on acupuncture point (ST36) in the organs, including the liver, spleen and kidney, of hSOD1G93A transgenic mice. We found that BV treatment at ST36 reduces inflammation in the liver, spleen, and kidney compared with saline-treatment at ST36 and BV injected intraperitoneally in symptomatic hSOD1G93A transgenic mice. Those findings suggest that BV treatment combined with acupuncture stimulation is more effective at reducing inflammation and increasing immune responses compared with only BV treatment, at least in an ALS animal model. Full article
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Open AccessArticle Murine Anorectic Response to Deoxynivalenol (Vomitoxin) Is Sex-Dependent
Toxins 2015, 7(8), 2845-2859; doi:10.3390/toxins7082845
Received: 5 June 2015 / Revised: 17 July 2015 / Accepted: 17 July 2015 / Published: 29 July 2015
Cited by 5 | PDF Full-text (874 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Deoxynivalenol (DON, vomitoxin), a common trichothecene mycotoxin found in cereal foods, dysregulates immune function and maintenance of energy balance. The purpose of this study was to determine if sex differences are similarly evident in DON’s anorectic responses in mice. A bioassay for feed
[...] Read more.
Deoxynivalenol (DON, vomitoxin), a common trichothecene mycotoxin found in cereal foods, dysregulates immune function and maintenance of energy balance. The purpose of this study was to determine if sex differences are similarly evident in DON’s anorectic responses in mice. A bioassay for feed refusal, previously developed by our lab, was used to compare acute i.p. exposures of 1 and 5 mg/kg bw DON in C57BL6 mice. Greater anorectic responses were seen in male than female mice. Male mice had higher organ and plasma concentrations of DON upon acute exposure than their female counterparts. A significant increase in IL-6 plasma levels was also observed in males while cholecystokinin response was higher in females. When effects of sex on food intake and body weight changes were compared after subchronic dietary exposure to 1, 2.5, and 10 ppm DON, males were found again to be more sensitive. Demonstration of male predilection to DON-induced changes in food intake and weight gain might an important consideration in future risk assessment of DON and other trichothecenes. Full article
(This article belongs to the Special Issue Mycotoxins and Human Diseases 2015)
Open AccessArticle O’Leary-Sant Symptom Index Predicts the Treatment Outcome for OnabotulinumtoxinA Injections for Refractory Interstitial Cystitis/Bladder Pain Syndrome
Toxins 2015, 7(8), 2860-2871; doi:10.3390/toxins7082860
Received: 15 June 2015 / Revised: 9 July 2015 / Accepted: 27 July 2015 / Published: 30 July 2015
Cited by 3 | PDF Full-text (266 KB) | HTML Full-text | XML Full-text
Abstract
Although intravesical injection of onabotulinumtoxinA (BoNT-A) has been proved promising in treating patients with interstitial cystitis/bladder pain syndrome (IC/BPS), what kind of patients that may benefit from this treatment remains unclear. This study investigated the predictors for a successful treatment outcome. Patients with
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Although intravesical injection of onabotulinumtoxinA (BoNT-A) has been proved promising in treating patients with interstitial cystitis/bladder pain syndrome (IC/BPS), what kind of patients that may benefit from this treatment remains unclear. This study investigated the predictors for a successful treatment outcome. Patients with IC/BPS who failed conventional treatments were enrolled to receive intravesical injection of 100 U of BoNT-A immediately followed by hydrodistention. Variables such as O’Leary-Sant symptom and problem indexes (ICSI and ICPI), pain visual analogue scale (VAS), functional bladder capacity (FBC), voiding diary, and urodynamic parameters were measured at baseline and six months after treatment. A global response assessment (GRA) ≥ 2 at six months was defined as successful. There were101 patients enrolled. Significant improvements were observed in mean ICSI, ICPI, OSS (ICSI + ICPI), pain VAS, FBC, frequency, nocturia and GRA at six months after BoNT-A injections (all p < 0.05). The successful rate at six months was 46/101 (45.54%). Multivariate logistic regression revealed the baseline ICSI (odds ratio = 0.770, 95% confidence interval = 0.601–0.989) was the only predictor for a treatment outcome. ICSI ≥ 12 was the most predictive cutoff value for a treatment failure, with a ROC area of 0.70 (sensitivity = 69.1%, specificity = 60.9%). Full article
(This article belongs to the collection Botulinum Toxins on Human Pain)
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Open AccessArticle Partial Characterization of Venom from the Colombian Spider Phoneutria Boliviensis (Aranae:Ctenidae)
Toxins 2015, 7(8), 2872-2887; doi:10.3390/toxins7082872
Received: 1 April 2015 / Revised: 3 June 2015 / Accepted: 29 June 2015 / Published: 31 July 2015
Cited by 4 | PDF Full-text (655 KB) | HTML Full-text | XML Full-text
Abstract
We report on the first studies on the characterization of venom from Phoneutria boliviensis (Aranae:Ctenidae) (F. O. Pickard-Cambridge, 1897), done with Colombian species. After the electrostimulation extraction process, the venom showed physicochemical properties corresponding to a colorless and water-soluble liquid with a density
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We report on the first studies on the characterization of venom from Phoneutria boliviensis (Aranae:Ctenidae) (F. O. Pickard-Cambridge, 1897), done with Colombian species. After the electrostimulation extraction process, the venom showed physicochemical properties corresponding to a colorless and water-soluble liquid with a density of 0.86 mg/mL and 87% aqueous content. P. boliviensis venom and RP-HPLC fractions showed hemolytic activity and hydrolyzed the synthetic substrate 4-nitro-3-octanoyloxy-benzoic acid, indicating the presence of phospholipases A2 enzymes. The electrophoretic profile showed an important protein content with molecular masses below 14 kDa, and differences between male and female protein content were also revealed. The RP-HPLC venom profile exposes differences between males and female content consistent with the electrophoretic profile. Five fractions collected from the RP-HPLC displayed significant larvicidal activity. Mass analysis indicates the presence of peptides ranging from 1047.71 to 3278.07 Da. Two peptides, Ctenitoxin-Pb48 and Ctenitoxin-Pb53, were partially identified using HPLC-nESI-MS/MS, which showed a high homology with other Ctenitoxins (family Tx3) from Phoneutria nigriventer, Phoneutria keyserlingi and Phoneutria reidyi affecting voltage-gated calcium receptors (Cav 1, 2.1, 2.2 and 2.3) and NMDA-glutamate receptors. Full article
(This article belongs to the Section Animal Venoms)
Open AccessArticle Molecular Cloning and Functional Studies of Two Kazal-Type Serine Protease Inhibitors Specifically Expressed by Nasonia vitripennis Venom Apparatus
Toxins 2015, 7(8), 2888-2905; doi:10.3390/toxins7082888
Received: 13 May 2015 / Revised: 29 June 2015 / Accepted: 27 July 2015 / Published: 4 August 2015
Cited by 3 | PDF Full-text (2021 KB) | HTML Full-text | XML Full-text
Abstract
Two cDNA sequences of Kazal-type serine protease inhibitors (KSPIs) in Nasonia vitripennis, NvKSPI-1 and NvKSPI-2, were characterized and their open reading frames (ORFs) were 198 and 264 bp, respectively. Both NvKSPI-1 and NvKSPI-2 contained a typical Kazal-type domain. Real-time quantitative PCR
[...] Read more.
Two cDNA sequences of Kazal-type serine protease inhibitors (KSPIs) in Nasonia vitripennis, NvKSPI-1 and NvKSPI-2, were characterized and their open reading frames (ORFs) were 198 and 264 bp, respectively. Both NvKSPI-1 and NvKSPI-2 contained a typical Kazal-type domain. Real-time quantitative PCR (RT-qPCR) results revealed that NvKSPI-1 and NvKSPI-2 mRNAs were mostly detected specifically in the venom apparatus, while they were expressed at lower levels in the ovary and much lower levels in other tissues tested. In the venom apparatus, both NvKSPI-1 and NvKSPI-2 transcripts were highly expressed on the fourth day post eclosion and then declined gradually. The NvKSPI-1 and NvKSPI-2 genes were recombinantly expressed utilizing a pGEX-4T-2 vector, and the recombinant products fused with glutathione S-transferase were purified. Inhibition of recombinant GST-NvKSPI-1 and GST-NvKSPI-2 to three serine protease inhibitors (trypsin, chymotrypsin, and proteinase K) were tested and results showed that only NvKSPI-1 could inhibit the activity of trypsin. Meanwhile, we evaluated the influence of the recombinant GST-NvKSPI-1 and GST-NvKSPI-2 on the phenoloxidase (PO) activity and prophenoloxidase (PPO) activation of hemolymph from a host pupa, Musca domestica. Results showed PPO activation in host hemolymph was inhibited by both recombinant proteins; however, there was no significant inhibition on the PO activity. Our results suggested that NvKSPI-1 and NvKSPI-2 could inhibit PPO activation in host hemolymph and trypsin activity in vitro. Full article
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Open AccessArticle Cross-Excitation in Peripheral Sensory Ganglia Associated with Pain Transmission
Toxins 2015, 7(8), 2906-2917; doi:10.3390/toxins7082906
Received: 21 May 2015 / Revised: 17 July 2015 / Accepted: 29 July 2015 / Published: 4 August 2015
Cited by 3 | PDF Full-text (1018 KB) | HTML Full-text | XML Full-text
Abstract
Despite the absence of synaptic contacts, cross-excitation of neurons in sensory ganglia during signal transmission is considered to be chemically mediated and appears increased in chronic pain states. In this study, we modulated neurotransmitter release in sensory neurons by direct application of type
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Despite the absence of synaptic contacts, cross-excitation of neurons in sensory ganglia during signal transmission is considered to be chemically mediated and appears increased in chronic pain states. In this study, we modulated neurotransmitter release in sensory neurons by direct application of type A botulinum neurotoxin (BoNT/A) to sensory ganglia in an animal model of neuropathic pain and evaluated the effect of this treatment on nocifensive. Unilateral sciatic nerve entrapment (SNE) reduced the ipsilateral hindpaw withdrawal threshold to mechanical stimulation and reduced hindpaw withdrawal latency to thermal stimulation. Direct application of BoNT/A to the ipsilateral L4 dorsal root ganglion (DRG) was localized in the cell bodies of the DRG and reversed the SNE-induced decreases in withdrawal thresholds within 2 days of BoNT/A administration. Results from this study suggest that neurotransmitter release within sensory ganglia is involved in the regulation of pain-related signal transmission. Full article
(This article belongs to the collection Botulinum Toxins on Human Pain)
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Open AccessArticle Effects of Hydrogen Peroxide on Different Toxigenic and Atoxigenic Isolates of Aspergillus flavus
Toxins 2015, 7(8), 2985-2999; doi:10.3390/toxins7082985
Received: 24 June 2015 / Revised: 21 July 2015 / Accepted: 27 July 2015 / Published: 5 August 2015
Cited by 4 | PDF Full-text (2111 KB) | HTML Full-text | XML Full-text
Abstract
Drought stress in the field has been shown to exacerbate aflatoxin contamination of maize and peanut. Drought and heat stress also produce reactive oxygen species (ROS) in plant tissues. Given the potential correlation between ROS and exacerbated aflatoxin production under drought and heat
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Drought stress in the field has been shown to exacerbate aflatoxin contamination of maize and peanut. Drought and heat stress also produce reactive oxygen species (ROS) in plant tissues. Given the potential correlation between ROS and exacerbated aflatoxin production under drought and heat stress, the objectives of this study were to examine the effects of hydrogen peroxide (H2O2)-induced oxidative stress on the growth of different toxigenic (+) and atoxigenic (−) isolates of Aspergillus flavus and to test whether aflatoxin production affects the H2O2 concentrations that the isolates could survive. Ten isolates were tested: NRRL3357 (+), A9 (+), AF13 (+), Tox4 (+), A1 (−), K49 (−), K54A (−), AF36 (−), and Aflaguard (−); and one A. parasiticus isolate, NRRL2999 (+). These isolates were cultured under a H2O2 gradient ranging from 0 to 50 mM in two different media, aflatoxin-conducive yeast extract-sucrose (YES) and non-conducive yeast extract-peptone (YEP). Fungal growth was inhibited at a high H2O2 concentration, but specific isolates grew well at different H2O2 concentrations. Generally the toxigenic isolates tolerated higher concentrations than did atoxigenic isolates. Increasing H2O2 concentrations in the media resulted in elevated aflatoxin production in toxigenic isolates. In YEP media, the higher concentration of peptone (15%) partially inactivated the H2O2 in the media. In the 1% peptone media, YEP did not affect the H2O2 concentrations that the isolates could survive in comparison with YES media, without aflatoxin production. It is interesting to note that the commercial biocontrol isolates, AF36 (−), and Aflaguard (−), survived at higher levels of stress than other atoxigenic isolates, suggesting that this testing method could potentially be of use in the selection of biocontrol isolates. Further studies will be needed to investigate the mechanisms behind the variability among isolates with regard to their degree of oxidative stress tolerance and the role of aflatoxin production. Full article
(This article belongs to the Section Mycotoxins)
Open AccessArticle Determination of Ochratoxin A in Wheat and Maize by Solid Bar Microextraction with Liquid Chromatography and Fluorescence Detection
Toxins 2015, 7(8), 3000-3011; doi:10.3390/toxins7083000
Received: 29 March 2015 / Revised: 26 July 2015 / Accepted: 31 July 2015 / Published: 5 August 2015
Cited by 7 | PDF Full-text (375 KB) | HTML Full-text | XML Full-text
Abstract
Solid bar microextraction (SBME), followed by liquid chromatography with fluorescence detection (HPLC-FLD), for the quantification of ochratoxin A in wheat and maize was developed. Ground wheat and maize grains were extracted with acetonitrile-water-acetic acid (79:20:1, v/v/v), followed by
[...] Read more.
Solid bar microextraction (SBME), followed by liquid chromatography with fluorescence detection (HPLC-FLD), for the quantification of ochratoxin A in wheat and maize was developed. Ground wheat and maize grains were extracted with acetonitrile-water-acetic acid (79:20:1, v/v/v), followed by defatting with cyclohexane, and subjected to SBME-LC-FLD analysis. SBME devices were constructed by packing 2 mg sorbent (C18) into porous polypropylene micro-tubes (2.5 cm length, 600 μm i.d., and 0.2 μm pore size). SBME devices were conditioned with methanol and placed into 5 mL stirred sample solutions for 70 min. After extraction, OTA was desorbed into 200 μL of methanol for 15 min, the solution was removed in vacuum, the residue was dissolved in 50 μL of methanol-water (1:1, v/v) and ochratoxin A content was determined by HPLC-FLD. Under optimized extraction conditions, the limit of detection of 0.9 μg·kg−1 and 2.5 μg·kg−1 and the precision of 3.4% and 5.0% over a concentration range of 1 to 100 μg·kg−1 in wheat and maize flour, respectively, were obtained. Full article
(This article belongs to the Section Mycotoxins)
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Open AccessArticle OTA-Grapes: A Mechanistic Model to Predict Ochratoxin A Risk in Grapes, a Step beyond the Systems Approach
Toxins 2015, 7(8), 3012-3029; doi:10.3390/toxins7083012
Received: 7 July 2015 / Revised: 28 July 2015 / Accepted: 31 July 2015 / Published: 6 August 2015
Cited by 6 | PDF Full-text (799 KB) | HTML Full-text | XML Full-text
Abstract
Ochratoxin A (OTA) is a fungal metabolite dangerous for human and animal health due to its nephrotoxic, immunotoxic, mutagenic, teratogenic and carcinogenic effects, classified by the International Agency for Research on Cancer in group 2B, possible human carcinogen. This toxin has been stated
[...] Read more.
Ochratoxin A (OTA) is a fungal metabolite dangerous for human and animal health due to its nephrotoxic, immunotoxic, mutagenic, teratogenic and carcinogenic effects, classified by the International Agency for Research on Cancer in group 2B, possible human carcinogen. This toxin has been stated as a wine contaminant since 1996. The aim of this study was to develop a conceptual model for the dynamic simulation of the A. carbonarius life cycle in grapes along the growing season, including OTA production in berries. Functions describing the role of weather parameters in each step of the infection cycle were developed and organized in a prototype model called OTA-grapes. Modelling the influence of temperature on OTA production, it emerged that fungal strains can be shared in two different clusters, based on the dynamic of OTA production and according to the optimal temperature. Therefore, two functions were developed, and based on statistical data analysis, it was assumed that the two types of strains contribute equally to the population. Model validation was not possible because of poor OTA contamination data, but relevant differences in OTA-I, the output index of the model, were noticed between low and high risk areas. To our knowledge, this is the first attempt to assess/model A. carbonarius in order to predict the risk of OTA contamination in grapes. Full article
(This article belongs to the collection Understanding Mycotoxin Occurrence in Food and Feed Chains)
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Open AccessArticle Citreoviridin Induces Autophagy-Dependent Apoptosis through Lysosomal-Mitochondrial Axis in Human Liver HepG2 Cells
Toxins 2015, 7(8), 3030-3044; doi:10.3390/toxins7083030
Received: 5 July 2015 / Revised: 27 July 2015 / Accepted: 31 July 2015 / Published: 6 August 2015
Cited by 6 | PDF Full-text (1086 KB) | HTML Full-text | XML Full-text
Abstract
Citreoviridin (CIT) is a mycotoxin derived from fungal species in moldy cereals. In our previous study, we reported that CIT stimulated autophagosome formation in human liver HepG2 cells. Here, we aimed to explore the relationship of autophagy with lysosomal membrane permeabilization and apoptosis
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Citreoviridin (CIT) is a mycotoxin derived from fungal species in moldy cereals. In our previous study, we reported that CIT stimulated autophagosome formation in human liver HepG2 cells. Here, we aimed to explore the relationship of autophagy with lysosomal membrane permeabilization and apoptosis in CIT-treated cells. Our data showed that CIT increased the expression of LC3-II, an autophagosome biomarker, from the early stage of treatment (6 h). After treatment with CIT for 12 h, lysosomal membrane permeabilization occurred, followed by the release of cathepsin D in HepG2 cells. Inhibition of autophagosome formation with siRNA against Atg5 attenuated CIT-induced lysosomal membrane permeabilization. In addition, CIT induced collapse of mitochondrial transmembrane potential as assessed by JC-1 staining. Furthermore, caspase-3 activity assay showed that CIT induced apoptosis in HepG2 cells. Inhibition of autophagosome formation attenuated CIT-induced apoptosis, indicating that CIT-induced apoptosis was autophagy-dependent. Cathepsin D inhibitor, pepstatin A, relieved CIT-induced apoptosis as well, suggesting the involvement of the lysosomal-mitochondrial axis in CIT-induced apoptosis. Taken together, our data demonstrated that CIT induced autophagy-dependent apoptosis through the lysosomal-mitochondrial axis in HepG2 cells. The study thus provides essential mechanistic insight, and suggests clues for the effective management and treatment of CIT-related diseases. Full article
(This article belongs to the Section Mycotoxins)
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Open AccessArticle The Metabolic Fate of Deoxynivalenol and Its Acetylated Derivatives in a Wheat Suspension Culture: Identification and Detection of DON-15-O-Glucoside, 15-Acetyl-DON-3-O-Glucoside and 15-Acetyl-DON-3-Sulfate
Toxins 2015, 7(8), 3112-3126; doi:10.3390/toxins7083112
Received: 24 June 2015 / Revised: 24 July 2015 / Accepted: 4 August 2015 / Published: 12 August 2015
Cited by 11 | PDF Full-text (1433 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Deoxynivalenol (DON) is a protein synthesis inhibitor produced by the Fusarium species, which frequently contaminates grains used for human or animal consumption. We treated a wheat suspension culture with DON or one of its acetylated derivatives, 3-acetyl-DON (3-ADON), 15-acetyl-DON (15-ADON) and 3,15-diacetyl-DON (3,15-diADON),
[...] Read more.
Deoxynivalenol (DON) is a protein synthesis inhibitor produced by the Fusarium species, which frequently contaminates grains used for human or animal consumption. We treated a wheat suspension culture with DON or one of its acetylated derivatives, 3-acetyl-DON (3-ADON), 15-acetyl-DON (15-ADON) and 3,15-diacetyl-DON (3,15-diADON), and monitored the metabolization over a course of 96 h. Supernatant and cell extract samples were analyzed using a tailored LC-MS/MS method for the quantification of DON metabolites. We report the formation of tentatively identified DON-15-O-β-D-glucoside (D15G) and of 15-acetyl-DON-3-sulfate (15-ADON3S) as novel deoxynivalenol metabolites in wheat. Furthermore, we found that the recently identified 15-acetyl-DON-3-O-β-D-glucoside (15-ADON3G) is the major metabolite produced after 15-ADON challenge. 3-ADON treatment led to a higher intracellular content of toxic metabolites after six hours compared to all other treatments. 3-ADON was exclusively metabolized into DON before phase II reactions occurred. In contrast, we found that 15-ADON was directly converted into 15-ADON3G and 15-ADON3S in addition to metabolization into deoxynivalenol-3-O-β-D-glucoside (D3G). This study highlights significant differences in the metabolization of DON and its acetylated derivatives. Full article
(This article belongs to the Section Mycotoxins)
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Open AccessArticle Increased Proinflammatory Cytokine Production and Decreased Cholesterol Efflux Due to Downregulation of ABCG1 in Macrophages Exposed to Indoxyl Sulfate
Toxins 2015, 7(8), 3155-3166; doi:10.3390/toxins7083155
Received: 6 July 2015 / Revised: 31 July 2015 / Accepted: 6 August 2015 / Published: 14 August 2015
Cited by 2 | PDF Full-text (708 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
One of the possible causes of enhanced atherosclerosis in patients with chronic kidney disease (CKD) is the accumulation of uremic toxins. Since macrophage foam cell formation is a hallmark of atherosclerosis, we examined the direct effect of indoxyl sulfate (IS), a representative uremic
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One of the possible causes of enhanced atherosclerosis in patients with chronic kidney disease (CKD) is the accumulation of uremic toxins. Since macrophage foam cell formation is a hallmark of atherosclerosis, we examined the direct effect of indoxyl sulfate (IS), a representative uremic toxin, on macrophage function. Macrophages differentiated from THP-1 cells were exposed to IS in vitro. IS decreased the cell viability of THP-1 derived macrophages but promoted the production of inflammatory cytokines (IL-1β, IS 1.0 mM: 101.8 ± 21.8 pg/mL vs. 0 mM: 7.0 ± 0.3 pg/mL, TNF-α, IS 1.0 mM: 96.6 ± 11.0 pg/mL vs. 0 mM: 15.1 ± 3.1 pg/mL) and reactive oxygen species. IS reduced macrophage cholesterol efflux (IS 0.5 mM: 30.3% ± 7.3% vs. 0 mM: 43.5% ± 1.6%) and decreased ATP-binding cassette transporter G1 expression. However, lipid uptake into cells was not enhanced. A liver X receptor (LXR) agonist, T0901317, improved IS-induced production of inflammatory cytokines as well as reduced cholesterol efflux. In conclusion, IS induced inflammatory reactions and reduced cholesterol efflux in macrophages. Both effects of IS were improved with activation of LXR. Direct interactions of uremic toxins with macrophages may be a major cause of atherosclerosis acceleration in patients with CKD. Full article
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Open AccessArticle Zearalenone in the Intestinal Tissues of Immature Gilts Exposed per os to Mycotoxins
Toxins 2015, 7(8), 3210-3223; doi:10.3390/toxins7083210
Received: 16 April 2015 / Revised: 31 July 2015 / Accepted: 11 August 2015 / Published: 18 August 2015
Cited by 10 | PDF Full-text (256 KB) | HTML Full-text | XML Full-text
Abstract
Zearalenone and its metabolites, α-zearalenol and β-zearalenol, demonstrate estradiol-like activity and disrupt physiological functions in animals. This article evaluates the carryover of zearalenone and its selected metabolites from the digesta to intestinal walls (along the entire intestines) in pre-pubertal gilts exposed to low
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Zearalenone and its metabolites, α-zearalenol and β-zearalenol, demonstrate estradiol-like activity and disrupt physiological functions in animals. This article evaluates the carryover of zearalenone and its selected metabolites from the digesta to intestinal walls (along the entire intestines) in pre-pubertal gilts exposed to low doses of zearalenone over long periods of time. The term “carryover” describes the transfer of mycotoxins from feed to edible tissues, and it was used to assess the risk of mycotoxin exposure for consumers. The experimental gilts with body weight of up to 25 kg were per os administered zearalenone at a daily dose of 40 μg/kg BW (Group E, n = 18) or placebo (Group C, n = 21) over a period of 42 days. In the first weeks of exposure, the highest values of the carryover factor were noted in the duodenum and the jejunum. In animals receiving pure zearalenone, the presence of metabolites was not determined in intestinal tissues. In the last three weeks of the experiment, very high values of the carryover factor were observed in the duodenum and the descending colon. The results of the study indicate that in animals exposed to subclinical doses of zearalenone, the carryover factor could be determined by the distribution and expression of estrogen receptor beta. Full article
(This article belongs to the collection Fusarium Toxins – Relevance for Human and Animal Health)
Open AccessArticle Spatiotemporal Dynamics of Microcystin Variants and Relationships with Environmental Parameters in Lake Taihu, China
Toxins 2015, 7(8), 3224-3244; doi:10.3390/toxins7083224
Received: 10 June 2015 / Revised: 5 August 2015 / Accepted: 11 August 2015 / Published: 18 August 2015
Cited by 11 | PDF Full-text (1517 KB) | HTML Full-text | XML Full-text
Abstract
Excessive anthropogenically-caused nutrient loading from both external and internal sources has promoted the growth of cyanobacteria in Lake Taihu from 2005 to 2014, suggesting increased production and release of cyanotoxins. In order to explain the spatial distribution and temporal variation of microcystins (MCs),
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Excessive anthropogenically-caused nutrient loading from both external and internal sources has promoted the growth of cyanobacteria in Lake Taihu from 2005 to 2014, suggesting increased production and release of cyanotoxins. In order to explain the spatial distribution and temporal variation of microcystins (MCs), the intracellular concentrations of MCs (MC-LR, -RR and -YR, L, R and Y are abbreviations of leucine, arginine and tyrosine) were monitored monthly from July 2013 to June 2014. Three MC variants are present simultaneously in Lake Taihu; the MC-LR and -RR variants were dominant (accounting for 40% and 39% of the total), followed by MC-YR (21%). However, MC-YR accounted for a higher proportion in colder months, especially in March. The highest concentrations of intracellular MCs were found in July and October when cyanobacteria cell density also reached the maximum. The average concentrations of MC-LR, -RR and -YR in July were 4.69, 4.23 and 2.01 μg/L, respectively. In terms of the entire lake, toxin concentrations in northern parts were significantly higher than the eastern part in summer, when MC concentrations were several times higher than the guideline value by WHO throughout much of Lake Taihu. Results from correlation and redundancy analysis (RDA) showed that total MCs, including all variants, were strongly and positively correlated with cyanobacteria cell density, water temperature, total phosphorus (TP) and pH, whereas each variant had different correlation coefficients with each of the considered environmental variables. MC-RR showed a stronger relationship with temperature, in contrast to MC-YR and -LR. Dissolved inorganic carbon (DIC) showed a negative relationship with each variant, suggesting that rising DIC concentrations may inhibit cyanobacterial growth and thereby reduce MC production in the future. Full article
(This article belongs to the Section Marine and Freshwater Toxins)
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Open AccessArticle Dendritic Cell Protection from Cisplatin Nephrotoxicity Is Independent of Neutrophils
Toxins 2015, 7(8), 3245-3256; doi:10.3390/toxins7083245
Received: 8 June 2015 / Revised: 11 August 2015 / Accepted: 12 August 2015 / Published: 19 August 2015
Cited by 7 | PDF Full-text (2030 KB) | HTML Full-text | XML Full-text
Abstract
Cisplatin is a very effective chemotherapeutic agent used against a wide range of solid tumors. A major adverse effect of cisplatin therapy is acute kidney injury (AKI). Neutrophils are reported to infiltrate and exacerbate injury in a wide range of sterile inflammatory models
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Cisplatin is a very effective chemotherapeutic agent used against a wide range of solid tumors. A major adverse effect of cisplatin therapy is acute kidney injury (AKI). Neutrophils are reported to infiltrate and exacerbate injury in a wide range of sterile inflammatory models of tissue injury. Here, we studied the kinetics of neutrophil infiltration into kidneys and their role in cisplatin-mediated AKI. Mice treated with cisplatin showed an increase in circulating neutrophils 24 and 48 h after cisplatin administration. Cisplatin treatment caused an increase in kidney leukocytes with neutrophils accounting for the majority of the infiltrating leukocytes. The extent of neutrophil infiltration coincided with the severity of kidney injury and renal dysfunction. To examine the functional relevance of infiltrating neutrophils in cisplatin nephrotoxicity, we depleted neutrophils using a neutrophil-specific antibody (anti-Ly-6G). This antibody resulted in greater than 90% depletion of neutrophils in both the blood and kidney. Of note, depletion of neutrophils had no impact on the extent of cisplatin-induced AKI as compared to non-depleted mice. Earlier, we reported that dendritic cell depletion in CD11c-DTRtg mice causes exacerbation of AKI and a dramatic increase in renal neutrophils. Thus, we also examined the role of neutrophils in dendritic cell-depleted mice treated with cisplatin. Dendritic cell depletion exacerbated AKI in spite of neutrophil depletion. These data demonstrate that cisplatin nephrotoxicity is not mediated by neutrophils and that dendritic cells protect kidneys via neutrophil-independent mechanisms. Full article
(This article belongs to the collection Toxicity and Therapeutic Interventions in the Immune System)
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Open AccessArticle Extracellular Xylanolytic and Pectinolytic Hydrolase Production by Aspergillus flavus Isolates Contributes to Crop Invasion
Toxins 2015, 7(8), 3257-3266; doi:10.3390/toxins7083257
Received: 6 July 2015 / Revised: 30 July 2015 / Accepted: 3 August 2015 / Published: 19 August 2015
Cited by 1 | PDF Full-text (450 KB) | HTML Full-text | XML Full-text
Abstract
Several atoxigenic Aspergillus flavus isolates, including some being used as biocontrol agents, and one toxigenic isolate were surveyed for the ability to produce extracellular xylanolytic and pectinolytic hydrolases. All of the tested isolates displayed good production of endoxylanases when grown on a medium
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Several atoxigenic Aspergillus flavus isolates, including some being used as biocontrol agents, and one toxigenic isolate were surveyed for the ability to produce extracellular xylanolytic and pectinolytic hydrolases. All of the tested isolates displayed good production of endoxylanases when grown on a medium utilizing larch xylan as a sole carbon substrate. Four of the tested isolates produced reasonably high levels of esterase activity, while the atoxigenic biocontrol agent NRRL 21882 isolate esterase level was significantly lower than the others. Atoxigenic A. flavus isolates 19, 22, K49, AF36 (the latter two are biocontrol agents) and toxigenic AF13 produced copious levels of pectinolytic activity when grown on a pectin medium. The pectinolytic activity levels of the atoxigenic A. flavus 17 and NRRL 21882 isolates were significantly lower than the other tested isolates. In addition, A. flavus isolates that displayed high levels of pectinolytic activity in the plate assay produced high levels of endopolygalacturonase (pectinase) P2c, as ascertained by isoelectric focusing electrophoresis. Isolate NRRL 21882 displayed low levels of both pectinase P2c and pectin methyl esterase. A. flavus appears capable of producing these hydrolytic enzymes irrespective of aflatoxin production. This ability of atoxigenic isolates to produce xylanolytic and pectinolytic hydrolases mimics that of toxigenic isolates and, therefore, contributes to the ability of atoxigenic isolates to occupy the same niche as A. flavus toxigenic isolates. Full article
(This article belongs to the collection Aflatoxins)
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Open AccessArticle Zearalenone and Its Derivatives α-Zearalenol and β-Zearalenol Decontamination by Saccharomyces cerevisiae Strains Isolated from Bovine Forage
Toxins 2015, 7(8), 3297-3308; doi:10.3390/toxins7083297
Received: 6 July 2015 / Revised: 4 August 2015 / Accepted: 7 August 2015 / Published: 20 August 2015
Cited by 6 | PDF Full-text (581 KB) | HTML Full-text | XML Full-text
Abstract
Zearalenone (ZEA) and its derivatives are mycotoxins with estrogenic effects on mammals. The biotransformation for ZEA in animals involves the formation of two major metabolites, α- and β-zearalenol (α-ZOL and β-ZOL), which are subsequently conjugated with glucuronic acid. The capability of Saccharomyces cerevisiae
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Zearalenone (ZEA) and its derivatives are mycotoxins with estrogenic effects on mammals. The biotransformation for ZEA in animals involves the formation of two major metabolites, α- and β-zearalenol (α-ZOL and β-ZOL), which are subsequently conjugated with glucuronic acid. The capability of Saccharomyces cerevisiae strains isolated from silage to eliminate ZEA and its derivatives α-ZOL and β-ZOL was investigated as, also, the mechanisms involved. Strains were grown on Yeast Extract-Peptone-Dextrose medium supplemented with the mycotoxins and their elimination from medium was quantified over time by HPLC-FL. A significant effect on the concentration of ZEA was observed, as all the tested strains were able to eliminate more than 90% of the mycotoxin from the culture medium in two days. The observed elimination was mainly due to ZEA biotransformation into β-ZOL (53%) and α-ZOL (8%) rather than to its adsorption to yeast cells walls. Further, the biotransformation of α-ZOL was not observed but a small amount of β-ZOL (6%) disappeared from culture medium. ZEA biotransformation by yeasts may not be regarded as a full detoxification process because both main end-products are still estrogenic. Nonetheless, it was observed that the biotransformation favors the formation of β-ZOL which is less estrogenic than ZEA and α-ZOL. This metabolic effect is only possible if active strains are used as feed additives and may play a role in the detoxification performance of products with viable S. cerevisiae cells. Full article
(This article belongs to the collection Understanding Mycotoxin Occurrence in Food and Feed Chains)
Open AccessArticle Presence of Multiple Mycotoxins and Other Fungal Metabolites in Native Grasses from a Wetland Ecosystem in Argentina Intended for Grazing Cattle
Toxins 2015, 7(8), 3309-3329; doi:10.3390/toxins7083309
Received: 27 June 2015 / Revised: 12 August 2015 / Accepted: 14 August 2015 / Published: 20 August 2015
Cited by 5 | PDF Full-text (394 KB) | HTML Full-text | XML Full-text
Abstract
The aim of this study was to evaluate the occurrence of several fungal metabolites, including mycotoxins in natural grasses (Poaceae) intended for grazing cattle. A total number of 72 and 77 different metabolites were detected on 106 and 69 grass samples collected during
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The aim of this study was to evaluate the occurrence of several fungal metabolites, including mycotoxins in natural grasses (Poaceae) intended for grazing cattle. A total number of 72 and 77 different metabolites were detected on 106 and 69 grass samples collected during 2011 and 2014, respectively. A total of 60 metabolites were found across both years. Among the few mycotoxins considered toxic for ruminants, no samples of natural grasses were contaminated with aflatoxins, ochratoxin A, ergot alkaloids, and gliotoxin, among others. However, we were able to detect important metabolites (toxic to ruminants) such as type A trichothecenes, mainly T-2 toxin and HT-2 toxin (up to 5000 µg/kg each), and zearalenone (up to 2000 µg/kg), all at very high frequencies and levels. Other fungal metabolites that were found to be prevalent were other Fusarium metabolites like beauvericin, equisetin and aurofusarin, metabolites produced by Alternaria spp., sterigmatocystin and its precursors and anthrachinone derivatives. It is important to point out that the profile of common metabolites was shared during both years of sampling, and also that the occurrence of important metabolites is not a sporadic event. Considering that this area of temperate grassland is used for grazing cattle all year long due to the richness in palatable grasses (Poaceae), the present work represents a starting point for further studies on the occurrence of multi-mycotoxins in natural grasses in order to have a complete picture of the extent of cattle exposure. Also, the present study shows that the presence of zeranol in urine of beef cattle may not be a consequence of illegal use of this banned substance, but the product of the natural occurrence of zearalenone and α-zearalenol in natural grasses intended for cattle feeding. Full article
(This article belongs to the collection Understanding Mycotoxin Occurrence in Food and Feed Chains)
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Open AccessArticle Protective Effects of Bacillus subtilis ANSB060 on Serum Biochemistry, Histopathological Changes and Antioxidant Enzyme Activities of Broilers Fed Moldy Peanut Meal Naturally Contaminated with Aflatoxins
Toxins 2015, 7(8), 3330-3343; doi:10.3390/toxins7083330
Received: 1 July 2015 / Revised: 10 August 2015 / Accepted: 11 August 2015 / Published: 21 August 2015
Cited by 6 | PDF Full-text (1494 KB) | HTML Full-text | XML Full-text
Abstract
The aim of this study was to investigate the toxic effects of aflatoxins and evaluate the effectiveness of Bacillus subtilis ANSB060 in detoxifying aflatoxicosis in broilers. A total of 360 one-week-old male broilers (Ross 308) were assigned to six dietary treatments for five
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The aim of this study was to investigate the toxic effects of aflatoxins and evaluate the effectiveness of Bacillus subtilis ANSB060 in detoxifying aflatoxicosis in broilers. A total of 360 one-week-old male broilers (Ross 308) were assigned to six dietary treatments for five weeks. The treatment diets were: C0 (basal diet); C1.0 (C0 + 1.0 g B. subtilis ANSB060/kg diet); M0 (basal diet formulated with moldy peanut meal); M0.5, M1.0 and M2.0 (M0 + 0.5, 1.0 and 2.0 g B. subtilis ANSB060/kg diet, respectively). The contents of aflatoxin B1, B2, G1 and G2 in the diets formulated with moldy peanut meal were 70.7 ± 1.3, 11.0 ± 1.5, 6.5 ± 0.8 and 2.0 ± 0.3 µg/kg, respectively. The results showed that aflatoxins increased (p < 0.05) serum aspartate transaminase activity, decreased (p < 0.05) serum glutathione peroxidase activity, and enhanced (p < 0.05) malondialdehyde contents in both the serum and liver. Aflatoxins also caused gross and histological changes in liver tissues, such as bile duct epithelium hyperplasia, vacuolar degeneration and lymphocyte infiltration. The supplementation of ANSB060 reduced aflatoxin levels in the duodenum and counteracted the negative effects of aflatoxins, leading to the conclusion that ANSB060 has a protective effect against aflatoxicosis and this protection is dose-related. Full article
(This article belongs to the collection Understanding Mycotoxin Occurrence in Food and Feed Chains)
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Open AccessArticle Signaling beyond Punching Holes: Modulation of Cellular Responses by Vibrio cholerae Cytolysin
Toxins 2015, 7(8), 3344-3358; doi:10.3390/toxins7083344
Received: 29 June 2015 / Revised: 12 August 2015 / Accepted: 14 August 2015 / Published: 21 August 2015
Cited by 3 | PDF Full-text (903 KB) | HTML Full-text | XML Full-text
Abstract
Pore-forming toxins (PFTs) are a distinct class of membrane-damaging cytolytic proteins that contribute significantly towards the virulence processes employed by various pathogenic bacteria. Vibrio cholerae cytolysin (VCC) is a prominent member of the beta-barrel PFT (beta-PFT) family. It is secreted by most of
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Pore-forming toxins (PFTs) are a distinct class of membrane-damaging cytolytic proteins that contribute significantly towards the virulence processes employed by various pathogenic bacteria. Vibrio cholerae cytolysin (VCC) is a prominent member of the beta-barrel PFT (beta-PFT) family. It is secreted by most of the pathogenic strains of the intestinal pathogen V. cholerae. Owing to its potent membrane-damaging cell-killing activity, VCC is believed to play critical roles in V. cholerae pathogenesis, particularly in those strains that lack the cholera toxin. Large numbers of studies have explored the mechanistic basis of the cell-killing activity of VCC. Consistent with the beta-PFT mode of action, VCC has been shown to act on the target cells by forming transmembrane oligomeric beta-barrel pores, thereby leading to permeabilization of the target cell membranes. Apart from the pore-formation-induced direct cell-killing action, VCC exhibits the potential to initiate a plethora of signal transduction pathways that may lead to apoptosis, or may act to enhance the cell survival/activation responses, depending on the type of target cells. In this review, we will present a concise view of our current understanding regarding the multiple aspects of these cellular responses, and their underlying signaling mechanisms, evoked by VCC. Full article
(This article belongs to the Special Issue The Cell Biology of Toxins and Effector Proteins from Vibrio cholerae)
Open AccessArticle Triggering of Erythrocyte Death by Triparanol
Toxins 2015, 7(8), 3359-3371; doi:10.3390/toxins7083359
Received: 22 July 2015 / Revised: 11 August 2015 / Accepted: 12 August 2015 / Published: 24 August 2015
Cited by 4 | PDF Full-text (586 KB) | HTML Full-text | XML Full-text
Abstract
The cholesterol synthesis inhibitor Triparanol has been shown to trigger apoptosis in several malignancies. Similar to the apoptosis of nucleated cells, erythrocytes may enter eryptosis, the suicidal death characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface.
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The cholesterol synthesis inhibitor Triparanol has been shown to trigger apoptosis in several malignancies. Similar to the apoptosis of nucleated cells, erythrocytes may enter eryptosis, the suicidal death characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include oxidative stress which may activate erythrocytic Ca2+ permeable unselective cation channels with subsequent Ca2+ entry and increase of cytosolic Ca2+ activity ([Ca2+]i). The present study explored whether and how Triparanol induces eryptosis. To this end, phosphatidylserine exposure at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, hemolysis from hemoglobin release, [Ca2+]i from Fluo3-fluorescence, and ROS formation from 2’,7’-dichlorodihydrofluorescein diacetate (DCFDA) dependent fluorescence. As a result, a 48 h exposure of human erythrocytes to Triparanol (20 µM) significantly increased DCFDA fluorescence and significantly increased Fluo3-fluorescence. Triparanol (15 µM) significantly increased the percentage of annexin-V-binding cells, and significantly decreased the forward scatter. The effect of Triparanol on annexin-V-binding was significantly blunted, but not abolished by removal of extracellular Ca2+. In conclusion, Triparanol leads to eryptosis, the suicidal erythrocyte death characterized by cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane. Triparanol is at least in part effective by stimulating ROS formation and Ca2+ entry. Full article

Review

Jump to: Research

Open AccessReview The Father, Son and Cholix Toxin: The Third Member of the DT Group Mono-ADP-Ribosyltransferase Toxin Family
Toxins 2015, 7(8), 2757-2772; doi:10.3390/toxins7082757
Received: 5 June 2015 / Revised: 17 July 2015 / Accepted: 20 July 2015 / Published: 24 July 2015
Cited by 1 | PDF Full-text (1998 KB) | HTML Full-text | XML Full-text
Abstract
The cholix toxin gene (chxA) was first identified in V. cholerae strains in 2007, and the protein was identified by bioinformatics analysis in 2008. It was identified as the third member of the diphtheria toxin group of mono-ADP-ribosyltransferase toxins along with P. aeruginosa
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The cholix toxin gene (chxA) was first identified in V. cholerae strains in 2007, and the protein was identified by bioinformatics analysis in 2008. It was identified as the third member of the diphtheria toxin group of mono-ADP-ribosyltransferase toxins along with P. aeruginosa exotoxin A and C. diphtheriae diphtheria toxin. Our group determined the structure of the full-length, three-domain cholix toxin at 2.1 Å and its C-terminal catalytic domain (cholixc) at 1.25 Å resolution. We showed that cholix toxin is specific for elongation factor 2 (diphthamide residue), similar to exotoxin A and diphtheria toxin. Cholix toxin possesses molecular features required for infection of eukaryotes by receptor-mediated endocytosis, translocation to the host cytoplasm and inhibition of protein synthesis. More recently, we also solved the structure of full-length cholix toxin in complex with NAD+ and proposed a new kinetic model for cholix enzyme activity. In addition, we have taken a computational approach that revealed some important properties of the NAD+-binding pocket at the residue level, including the role of crystallographic water molecules in the NAD+ substrate interaction. We developed a pharmacophore model of cholix toxin, which revealed a cationic feature in the side chain of cholix toxin active-site inhibitors that may determine the active pose. Notably, several recent reports have been published on the role of cholix toxin as a major virulence factor in V. cholerae (non-O1/O139 strains). Additionally, FitzGerald and coworkers prepared an immunotoxin constructed from domains II and III as a cancer treatment strategy to complement successful immunotoxins derived from P. aeruginosa exotoxin A. Full article
(This article belongs to the Special Issue The Cell Biology of Toxins and Effector Proteins from Vibrio cholerae)
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Open AccessReview Temporomandibular Myofacial Pain Treated with Botulinum Toxin Injection
Toxins 2015, 7(8), 2791-2800; doi:10.3390/toxins7082791
Received: 14 June 2015 / Accepted: 13 July 2015 / Published: 24 July 2015
Cited by 3 | PDF Full-text (447 KB) | HTML Full-text | XML Full-text
Abstract
This article reviews the diagnoses and treatment of temporomandibular disorders (TMD) and outlines of the role of botulinum toxin (BoNT) in the treatment of myofacial TMD. This manuscript includes a brief history of the use of BoNT in the treatment of pain, the
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This article reviews the diagnoses and treatment of temporomandibular disorders (TMD) and outlines of the role of botulinum toxin (BoNT) in the treatment of myofacial TMD. This manuscript includes a brief history of the use of BoNT in the treatment of pain, the mechanism of action of BoNT, and the techniques for injections, adverse effects and contraindications when using BoNT to treat mayofacial pain caused by TMD. Full article
(This article belongs to the collection Botulinum Toxins on Human Pain)
Open AccessReview Activities and Effects of Ergot Alkaloids on Livestock Physiology and Production
Toxins 2015, 7(8), 2801-2821; doi:10.3390/toxins7082801
Received: 8 April 2015 / Revised: 8 July 2015 / Accepted: 9 July 2015 / Published: 27 July 2015
Cited by 10 | PDF Full-text (334 KB) | HTML Full-text | XML Full-text
Abstract
Consumption of feedstuffs contaminated with ergot alkaloids has a broad impact on many different physiological mechanisms that alters the homeostasis of livestock. This change in homeostasis causes an increased sensitivity in livestock to perturbations in the ambient environment, resulting in an increased sensitivity
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Consumption of feedstuffs contaminated with ergot alkaloids has a broad impact on many different physiological mechanisms that alters the homeostasis of livestock. This change in homeostasis causes an increased sensitivity in livestock to perturbations in the ambient environment, resulting in an increased sensitivity to such stressors. This ultimately results in large financial losses in the form of production losses to livestock producers around the world. This review will focus on the underlying physiological mechanisms that are affected by ergot alkaloids that lead to decreases in livestock production. Full article
(This article belongs to the Special Issue Ergot Alkaloids: Chemistry, Biology and Toxicology)
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Open AccessReview Interactions between Autophagy and Bacterial Toxins: Targets for Therapy?
Toxins 2015, 7(8), 2918-2958; doi:10.3390/toxins7082918
Received: 1 April 2015 / Revised: 27 July 2015 / Accepted: 28 July 2015 / Published: 4 August 2015
Cited by 3 | PDF Full-text (979 KB) | HTML Full-text | XML Full-text
Abstract
Autophagy is a physiological process involved in defense mechanisms for clearing intracellular bacteria. The autophagic pathway is finely regulated and bacterial toxins interact with this process in a complex manner. Bacterial toxins also interact significantly with many biochemical processes. Evaluations of the effects
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Autophagy is a physiological process involved in defense mechanisms for clearing intracellular bacteria. The autophagic pathway is finely regulated and bacterial toxins interact with this process in a complex manner. Bacterial toxins also interact significantly with many biochemical processes. Evaluations of the effects of bacterial toxins, such as endotoxins, pore-forming toxins and adenylate cyclases, on autophagy could support the development of new strategies for counteracting bacterial pathogenicity. Treatment strategies could focus on drugs that enhance autophagic processes to improve the clearance of intracellular bacteria. However, further in vivo studies are required to decipher the upregulation of autophagy and potential side effects limiting such approaches. The capacity of autophagy activation strategies to improve the outcome of antibiotic treatment should be investigated in the future. Full article
(This article belongs to the Section Bacterial Toxins)
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Open AccessReview G-Protein-Coupled Receptors: Next Generation Therapeutic Targets in Head and Neck Cancer?
Toxins 2015, 7(8), 2959-2984; doi:10.3390/toxins7082959
Received: 12 May 2015 / Revised: 22 June 2015 / Accepted: 20 July 2015 / Published: 5 August 2015
Cited by 7 | PDF Full-text (1753 KB) | HTML Full-text | XML Full-text
Abstract
Therapeutic outcome in head and neck squamous cell carcinoma (HNSCC) is poor in most advanced cases. To improve therapeutic efficiency, novel therapeutic targets and prognostic factors must be discovered. Our studies have identified several G protein-coupled receptors (GPCRs) as promising candidates. Significant epigenetic
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Therapeutic outcome in head and neck squamous cell carcinoma (HNSCC) is poor in most advanced cases. To improve therapeutic efficiency, novel therapeutic targets and prognostic factors must be discovered. Our studies have identified several G protein-coupled receptors (GPCRs) as promising candidates. Significant epigenetic silencing of GPCR expression occurs in HNSCC compared with normal tissue, and is significantly correlated with clinical behavior. Together with the finding that GPCR activity can suppress tumor cell growth, this indicates that GPCR expression has potential utility as a prognostic factor. In this review, we discuss the roles that galanin receptor type 1 (GALR1) and type 2 (GALR2), tachykinin receptor type 1 (TACR1), and somatostatin receptor type 1 (SST1) play in HNSCC. GALR1 inhibits proliferation of HNSCC cells though ERK1/2-mediated effects on cell cycle control proteins such as p27, p57, and cyclin D1, whereas GALR2 inhibits cell proliferation and induces apoptosis in HNSCC cells. Hypermethylation of GALR1, GALR2, TACR1, and SST1 is associated with significantly reduced disease-free survival and a higher recurrence rate. Although their overall activities varies, each of these GPCRs has value as both a prognostic factor and a therapeutic target. These data indicate that further study of GPCRs is a promising strategy that will enrich pharmacogenomics and prognostic research in HNSCC. Full article
(This article belongs to the Special Issue G-Protein Coupled Receptors as mediators of Toxin effects)
Open AccessReview Ultrasound-Guided Injection of Botulinum Toxin Type A for Piriformis Muscle Syndrome: A Case Report and Review of the Literature
Toxins 2015, 7(8), 3045-3056; doi:10.3390/toxins7083045
Received: 6 July 2015 / Revised: 23 July 2015 / Accepted: 5 August 2015 / Published: 10 August 2015
Cited by 5 | PDF Full-text (437 KB) | HTML Full-text | XML Full-text
Abstract
Piriformis muscle syndrome (PMS) is caused by prolonged or excessive contraction of the piriformis muscle associated with pain in the buttocks, hips, and lower limbs because of the close proximity to the sciatic nerve. Botulinum toxin type A (BoNT-A) reduces muscle hypertonia as
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Piriformis muscle syndrome (PMS) is caused by prolonged or excessive contraction of the piriformis muscle associated with pain in the buttocks, hips, and lower limbs because of the close proximity to the sciatic nerve. Botulinum toxin type A (BoNT-A) reduces muscle hypertonia as well as muscle contracture and pain inhibiting substance P release and other inflammatory factors. BoNT-A injection technique is important considering the difficult access of the needle for deep location, the small size of the muscle, and the proximity to neurovascular structures. Ultrasound guidance is easy to use and painless and several studies describe its use during BoNT-A administration in PMS. In the present review article, we briefly updated current knowledge regarding the BoNT therapy of PMS, describing also a case report in which this syndrome was treated with an ultrasound-guided injection of incobotulinumtoxin A. Pain reduction with an increase of hip articular range of motion in this patient with PMS confirmed the effectiveness of BoNT-A injection for the management of this syndrome. Full article
(This article belongs to the collection Botulinum Toxins on Human Pain)
Open AccessReview Review on Mycotoxin Issues in Ruminants: Occurrence in Forages, Effects of Mycotoxin Ingestion on Health Status and Animal Performance and Practical Strategies to Counteract Their Negative Effects
Toxins 2015, 7(8), 3057-3111; doi:10.3390/toxins7083057
Received: 15 June 2015 / Revised: 30 July 2015 / Accepted: 31 July 2015 / Published: 12 August 2015
Cited by 28 | PDF Full-text (444 KB) | HTML Full-text | XML Full-text
Abstract
Ruminant diets include cereals, protein feeds, their by-products as well as hay and grass, grass/legume, whole-crop maize, small grain or sorghum silages. Furthermore, ruminants are annually or seasonally fed with grazed forage in many parts of the World. All these forages could be
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Ruminant diets include cereals, protein feeds, their by-products as well as hay and grass, grass/legume, whole-crop maize, small grain or sorghum silages. Furthermore, ruminants are annually or seasonally fed with grazed forage in many parts of the World. All these forages could be contaminated by several exometabolites of mycotoxigenic fungi that increase and diversify the risk of mycotoxin exposure in ruminants compared to swine and poultry that have less varied diets. Evidence suggests the greatest exposure for ruminants to some regulated mycotoxins (aflatoxins, trichothecenes, ochratoxin A, fumonisins and zearalenone) and to many other secondary metabolites produced by different species of Alternaria spp. (e.g., AAL toxins, alternariols, tenuazonic acid or 4Z-infectopyrone), Aspergillus flavus (e.g., kojic acid, cyclopiazonic acid or β-nitropropionic acid), Aspergillus fuminatus (e.g., gliotoxin, agroclavine, festuclavines or fumagillin), Penicillium roqueforti and P. paneum (e.g., mycophenolic acid, roquefortines, PR toxin or marcfortines) or Monascus ruber (citrinin and monacolins) could be mainly related to forage contamination. This review includes the knowledge of mycotoxin occurrence reported in the last 15 years, with special emphasis on mycotoxins detected in forages, and animal toxicological issues due to their ingestion. Strategies for preventing the problem of mycotoxin feed contamination under farm conditions are discussed. Full article
(This article belongs to the collection Understanding Mycotoxin Occurrence in Food and Feed Chains)
Open AccessReview Botulinum Toxin for Neuropathic Pain: A Review of the Literature
Toxins 2015, 7(8), 3127-3154; doi:10.3390/toxins7083127
Received: 27 June 2015 / Revised: 29 July 2015 / Accepted: 7 August 2015 / Published: 14 August 2015
Cited by 21 | PDF Full-text (670 KB) | HTML Full-text | XML Full-text
Abstract
Botulinum neurotoxin (BoNT), derived from Clostridium botulinum, has been used therapeutically for focal dystonia, spasticity, and chronic migraine. Its spectrum as a potential treatment for neuropathic pain has grown. Recent opinions on the mechanism behind the antinociceptive effects of BoNT suggest that
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Botulinum neurotoxin (BoNT), derived from Clostridium botulinum, has been used therapeutically for focal dystonia, spasticity, and chronic migraine. Its spectrum as a potential treatment for neuropathic pain has grown. Recent opinions on the mechanism behind the antinociceptive effects of BoNT suggest that it inhibits the release of peripheral neurotransmitters and inflammatory mediators from sensory nerves. There is some evidence showing the axonal transport of BoNT, but it remains controversial. The aim of this review is to summarize the experimental and clinical evidence of the antinociceptive effects, mechanisms, and therapeutic applications of BoNT for neuropathic pain conditions, including postherpetic neuralgia, complex regional pain syndrome, and trigeminal neuralgia. The PubMed and OvidSP databases were searched from 1966 to May 2015. We assessed levels of evidence according to the American Academy of Neurology guidelines. Recent studies have suggested that BoNT injection is an effective treatment for postherpetic neuralgia and is likely efficient for trigeminal neuralgia and post-traumatic neuralgia. BoNT could also be effective as a treatment for diabetic neuropathy. It has not been proven to be an effective treatment for occipital neuralgia or complex regional pain syndrome. Full article
(This article belongs to the collection Botulinum Toxins on Human Pain)
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Open AccessReview Anthrax Toxins in Context of Bacillus anthracis Spores and Spore Germination
Toxins 2015, 7(8), 3167-3178; doi:10.3390/toxins7083167
Received: 29 July 2015 / Revised: 8 August 2015 / Accepted: 11 August 2015 / Published: 17 August 2015
Cited by 3 | PDF Full-text (387 KB) | HTML Full-text | XML Full-text
Abstract
The interaction of anthrax toxin or toxin components with B. anthracis spores has been demonstrated. Germinating spores can produce significant amounts of toxin components very soon after the initiation of germination. In this review, we will summarize the work performed that has led
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The interaction of anthrax toxin or toxin components with B. anthracis spores has been demonstrated. Germinating spores can produce significant amounts of toxin components very soon after the initiation of germination. In this review, we will summarize the work performed that has led to our understanding of toxin and spore interactions and discuss the complexities associated with these interactions Full article
(This article belongs to the collection Anthrax Toxins)
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Open AccessReview Pharmacological Alternatives for the Treatment of Neurodegenerative Disorders: Wasp and Bee Venoms and Their Components as New Neuroactive Tools
Toxins 2015, 7(8), 3179-3209; doi:10.3390/toxins7083179
Received: 15 May 2015 / Revised: 1 August 2015 / Accepted: 5 August 2015 / Published: 18 August 2015
Cited by 8 | PDF Full-text (835 KB) | HTML Full-text | XML Full-text
Abstract
Neurodegenerative diseases are relentlessly progressive, severely impacting affected patients, families and society as a whole. Increased life expectancy has made these diseases more common worldwide. Unfortunately, available drugs have insufficient therapeutic effects on many subtypes of these intractable diseases, and adverse effects hamper
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Neurodegenerative diseases are relentlessly progressive, severely impacting affected patients, families and society as a whole. Increased life expectancy has made these diseases more common worldwide. Unfortunately, available drugs have insufficient therapeutic effects on many subtypes of these intractable diseases, and adverse effects hamper continued treatment. Wasp and bee venoms and their components are potential means of managing or reducing these effects and provide new alternatives for the control of neurodegenerative diseases. These venoms and their components are well-known and irrefutable sources of neuroprotectors or neuromodulators. In this respect, the present study reviews our current understanding of the mechanisms of action and future prospects regarding the use of new drugs derived from wasp and bee venom in the treatment of major neurodegenerative disorders, including Alzheimer’s Disease, Parkinson’s Disease, Epilepsy, Multiple Sclerosis and Amyotrophic Lateral Sclerosis. Full article
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Open AccessReview Genetic Factors Involved in Fumonisin Accumulation in Maize Kernels and Their Implications in Maize Agronomic Management and Breeding
Toxins 2015, 7(8), 3267-3296; doi:10.3390/toxins7083267
Received: 1 June 2015 / Revised: 5 August 2015 / Accepted: 11 August 2015 / Published: 20 August 2015
Cited by 9 | PDF Full-text (542 KB) | HTML Full-text | XML Full-text
Abstract
Contamination of maize with fumonisins depends on the environmental conditions; the maize resistance to contamination and the interaction between both factors. Although the effect of environmental factors is a determinant for establishing the risk of kernel contamination in a region, there is sufficient
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Contamination of maize with fumonisins depends on the environmental conditions; the maize resistance to contamination and the interaction between both factors. Although the effect of environmental factors is a determinant for establishing the risk of kernel contamination in a region, there is sufficient genetic variability among maize to develop resistance to fumonisin contamination and to breed varieties with contamination at safe levels. In addition, ascertaining which environmental factors are the most important in a region will allow the implementation of risk monitoring programs and suitable cultural practices to reduce the impact of such environmental variables. The current paper reviews all works done to address the influence of environmental variables on fumonisin accumulation, the genetics of maize resistance to fumonisin accumulation, and the search for the biochemical and/or structural mechanisms of the maize plant that could be involved in resistance to fumonisin contamination. We also explore the outcomes of breeding programs and risk monitoring of undertaken projects. Full article
(This article belongs to the collection Understanding Mycotoxin Occurrence in Food and Feed Chains)
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