Toxins

16 pages, 6101 KiB

Open AccessArticle

Enhancing the Cytotoxicity and Apoptotic Efficacy of Parasporin-2-Derived Variants (Mpp46Aa1) on Cancer Cell Lines

by Juan S. Alarcón-Aldana, Lydia Visser, Nohora J. Rueda-Forero, Efraín H. Pinzón-Reyes, Paola Rondón-Villarreal and Miguel O. Suárez-Barrera

Toxins 2024, 16(10), 415; https://doi.org/10.3390/toxins16100415 - 25 Sep 2024

Abstract

Parasporin PS2Aa1, recently renamed Mpp46Aa1, is an anti-cancer protein known for its selectivity against various human cancer cell lines. We genetically modified native PS2Aa1 to create a library of approximately 100 mutants. From this library, we selected promising mutants based on their half-maximal [...] Read more.

Parasporin PS2Aa1, recently renamed Mpp46Aa1, is an anti-cancer protein known for its selectivity against various human cancer cell lines. We genetically modified native PS2Aa1 to create a library of approximately 100 mutants. From this library, we selected promising mutants based on their half-maximal inhibitory concentration (IC₅₀) and sequence variations. In this study, Variant 3–35, with the G257V substitution, demonstrated increased cytotoxicity and selectivity against the colon cancer cell line SW480. Conversely, Variant N65, featuring substitutions N92D, K175R, and S218G, yielded the most favorable results against the cancer cell lines SW-620, MOLT-4, and Jurkat. The caspase 3/7 and 9, Annexin V-Cy3 and 6-GFDA activities, and, most notably, mitochondrial membrane permeabilization assays confirmed the apoptotic marker elevation. These findings indicate that residues 92, 175, 218, and 257 may play a critical role in the cytotoxic activity and selectivity. We successfully obtained genetically improved variants with substitutions at these key amino acid positions. Additionally, we conducted molecular dynamic simulations to explore the potential interactions between PS2Aa1 and the CD59 GPI-anchored protein. The simulation results revealed that residues 57, 92, and 101 were consistently present, suggesting their possible significance in the interactions between parasporin and the CD59 protein. Full article

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15 pages, 1341 KiB

Open AccessArticle

Effect of Temperature, Relative Humidity, and Incubation Time on the Mycotoxin Production by Fusarium spp. Responsible for Dry Rot in Potato Tubers

by Maria Gutiérrez-Pozo, Carol Verheecke-Vaessen, Sofia Kourmpetli, Leon A. Terry and Angel Medina

Toxins 2024, 16(10), 414; https://doi.org/10.3390/toxins16100414 - 24 Sep 2024

Abstract

Potato is the fourth most consumed crop in the world. More than half of the crop is stored for three to nine months at cold temperatures (3–10 °C) for the fresh and seed market. One of the main causes of fresh potato waste [...] Read more.

Potato is the fourth most consumed crop in the world. More than half of the crop is stored for three to nine months at cold temperatures (3–10 °C) for the fresh and seed market. One of the main causes of fresh potato waste in the retail supply chain is the processing of fungal and bacterial rots during storage. Dry rot is a fungal disease that mainly affects the potato crop during storage and is responsible for 1% of tuber losses in the UK. It is produced by Fusarium spp., such as Fusarium sambucinum and F. oxysporum, which can lead to the accumulation of mycotoxins in the potato tuber. Little is known about the impact of environmental factors on the accumulation of mycotoxins in potato tubers. Understanding the ecophysiology of these fungi is key to mitigating their occurrence under commercial storage conditions. Therefore, this work aimed to elucidate the effect of three different temperatures (5, 10, and 15 °C) and two different water activities (a_w; 0.97, 0.99) on the ecophysiology and mycotoxin accumulation of F. sambucinum and F. oxysporum in a potato-based semi-synthetic medium. The mycotoxin accumulation was then studied in vivo, in potato tubers cultivated under organic farming conditions, stored for 40 days at 8.5 °C. Results showed that higher temperatures and a_w enhanced fungal growth, lag time, and mycotoxin accumulation in vitro. Growth rate was 2 and 3.6 times higher when the temperature increased from 5 to 10 and 15 °C, respectively. Six different mycotoxins (T-2, HT-2, diacetoxyscirpenol, 15-acetoxyscirpenol, neosolaniol, and beauvericin) were detected in vitro and in vivo. T-2 was the most abundant mycotoxin detected in vitro, observing 10⁶ ng of T-2/g media after 21 days of incubation at 10 °C and 0.99 a_w. Due to the long period of time that potato tubers spend in storage, the fluctuations of environmental factors, such as temperature and relative humidity, could promote the development of fungal rot, as well as mycotoxin accumulation. This could result in important food and economic losses for the potato market and a threat to food safety. Full article

(This article belongs to the Collection Editorial Board Members’ Collection Series: Fungal Metabolites: From Toxins to Therapeutics)

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15 pages, 2730 KiB

Open AccessReview

Ultrasound-Guided Botulinum Toxin-A Injections into the Masseter Muscle for Both Medical and Aesthetic Purposes

by Marius Nicolae Popescu, Cristina Beiu, Carmen Andrada Iliescu, Andreea Racoviță, Mihai Berteanu, Mădălina Gabriela Iliescu, Ana Maria Alexandra Stănescu, Diana Sabina Radaschin and Liliana Gabriela Popa

Toxins 2024, 16(10), 413; https://doi.org/10.3390/toxins16100413 - 24 Sep 2024

Abstract

With the increasing use of Botulinum toxin type A (BoNT-A) injections in the masseter muscles for both medical and aesthetic purposes, there is a constant need to continually enhance the efficacy of these treatments and reduce the risk of potential adverse events. This [...] Read more.

With the increasing use of Botulinum toxin type A (BoNT-A) injections in the masseter muscles for both medical and aesthetic purposes, there is a constant need to continually enhance the efficacy of these treatments and reduce the risk of potential adverse events. This review provides an in-depth analysis of the masseter muscle’s anatomical structure and essential landmarks and emphasizes the advantages of ultrasound (US) guidance in improving the precision of BoNT-A injections compared to conventional blind methods. The review is supplemented with comprehensive figures, including graphics, clinical images, and ultrasound visuals, to support the discussion. Potential complications such as paradoxical bulging, inadvertent injections into the risorius muscle or parotid gland, facial paralysis, and the risk of bone resorption are examined. Future research should aim at refining injection techniques and assessing the long-term effects of repeated treatments to ensure optimal patient care and safety. Full article

(This article belongs to the Special Issue Botulinum Toxins: New Uses in the Treatment of Diseases (Volume II))

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28 pages, 4713 KiB

Open AccessArticle

A Monoclonal Antibody with a High Affinity for Ricin Isoforms D and E Provides Strong Protection against Ricin Poisoning

by Loïs Lequesne, Julie Dano, Audrey Rouaix, Camille Kropp, Marc Plaisance, Stéphanie Gelhaye, Marie-Lou Lequesne, Paloma Piquet, Arnaud Avril, François Becher, Maria Lucia Orsini Delgado and Stéphanie Simon

Toxins 2024, 16(10), 412; https://doi.org/10.3390/toxins16100412 - 24 Sep 2024

Abstract

Ricin is a highly potent toxin that has been used in various attempts at bioterrorism worldwide. Although a vaccine for preventing ricin poisoning (RiVax™) is in clinical development, there are currently no commercially available prophylaxis or treatments for ricin intoxication. Numerous studies have [...] Read more.

Ricin is a highly potent toxin that has been used in various attempts at bioterrorism worldwide. Although a vaccine for preventing ricin poisoning (RiVax™) is in clinical development, there are currently no commercially available prophylaxis or treatments for ricin intoxication. Numerous studies have highlighted the potential of passive immunotherapy using anti-ricin monoclonal antibodies (mAbs) and have shown promising results in preclinical models. In this article, we describe the neutralizing and protective efficacy of a new generation of high-affinity anti-ricin mAbs, which bind and neutralize very efficiently both ricin isoforms D and E in vitro through cytotoxicity cell assays. In vivo, protection assay revealed that one of these mAbs (RicE5) conferred over 90% survival in a murine model challenged intranasally with a 5 LD₅₀ of ricin and treated by intravenous administration of the mAbs 6 h post-intoxication. Notably, a 35% survival rate was observed even when treatment was administered 24 h post-exposure. Moreover, all surviving mice exhibited long-term immunity to high ricin doses. These findings offer promising results for the clinical development of a therapeutic candidate against ricin intoxication and may also pave the way for novel vaccination strategies against ricin or other toxins. Full article

(This article belongs to the Section Plant Toxins)

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13 pages, 3079 KiB

Open AccessArticle

Brevetoxin Aptamer Selection and Biolayer Interferometry Biosensor Application

by Bo Hu, Sheng-Qun Ouyang, Yu-Ping Zhu, Xiao-Ling Lu, Zhe Ning, Bing-Hua Jiao, Liang-Hua Wang, Hao-Bing Yu and Xiao-Yu Liu

Toxins 2024, 16(10), 411; https://doi.org/10.3390/toxins16100411 - 24 Sep 2024

Abstract

Brevetoxins (PbTxs) are very potent marine neurotoxins that can cause an illness clinically described as neurologic shellfish poisoning (NSP). These toxins are cyclic polyether in chemistry and have increased their geographical distribution in the past 2 decades. However, the ethical problems as well [...] Read more.

Brevetoxins (PbTxs) are very potent marine neurotoxins that can cause an illness clinically described as neurologic shellfish poisoning (NSP). These toxins are cyclic polyether in chemistry and have increased their geographical distribution in the past 2 decades. However, the ethical problems as well as technical difficulties associated with currently employed analysis methods for marine toxins have spurred the quest for suitable alternatives to be applied in a regulatory monitoring regime. In this work, we reported the first instance of concurrent aptamer selection of Brevetoxin-1 (PbTx-1) and Brevetoxin-2 (PbTx-2) and constructed a biolayer interferometry (BLI) biosensor utilizing PbTx-1 aptamer as a specific recognition element. Through an in vitro selection process, we have, for the first time, successfully selected DNA aptamers with high affinity and specificity to PbTx-1 and PbTx-2 from a vast pool of random sequences. Among the selected aptamers, aptamer A5 exhibited the strongest binding affinity to PbTx-1, with an equilibrium dissociation constant (K_D) of 2.56 μM. Subsequently, we optimized aptamer A5 by truncation to obtain the core sequence (A5-S3). Further refinement was achieved through mutations based on the predictions of a QGRS mapper, resulting in aptamer A5-S3G, which showed a significant increase in the K_D value by approximately 100-fold. Utilizing aptamer A5-S3G, we fabricated a label-free, real-time optical BLI aptasensor for the detection of PbTx-1. This aptasensor displayed a broad detection range from 100 nM to 4000 nM PbTx-1, with a linear range between 100 nM and 2000 nM, and a limit of detection (LOD) as low as 4.5 nM. Importantly, the aptasensor showed no cross-reactivity to PbTx-2 or other marine toxins, indicating a high level of specificity for PbTx-1. Moreover, the aptasensor exhibited excellent reproducibility and stability when applied for the detection of PbTx-1 in spiked shellfish samples. We strongly believe that this innovative aptasensor offers a promising alternative to traditional immunological methods for the specific and reliable detection of PbTx-1. Full article

(This article belongs to the Special Issue Unraveling the Environmental Threat of Harmful Algae Blooms (HABs): Causes and Impacts)

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Graphical abstract

14 pages, 2748 KiB

Open AccessArticle

Identification of New Angiotensin-Converting Enzyme Inhibitory Peptides Isolated from the Hydrolysate of the Venom of Nemopilema nomurai Jellyfish

by Ramachandran Loganathan Mohan Prakash, Deva Asirvatham Ravi, Du Hyeon Hwang, Changkeun Kang and Euikyung Kim

Toxins 2024, 16(9), 410; https://doi.org/10.3390/toxins16090410 - 20 Sep 2024

Abstract

Recently, jellyfish venom has gained attention as a promising reservoir of pharmacologically active compounds, with potential applications in new drug development. In this investigation, novel peptides, isolated from the hydrolysates of Nemopilema nomurai jellyfish venom (NnV), demonstrate potent inhibitory activities against angiotensin-converting enzyme [...] Read more.

Recently, jellyfish venom has gained attention as a promising reservoir of pharmacologically active compounds, with potential applications in new drug development. In this investigation, novel peptides, isolated from the hydrolysates of Nemopilema nomurai jellyfish venom (NnV), demonstrate potent inhibitory activities against angiotensin-converting enzyme (ACE). Proteolytic enzymes—specifically, papain and protamex—were utilized for the hydrolysis under optimized enzymatic conditions, determined by assessing the degree of hydrolysis through the ninhydrin test. Comparative analyses revealed that papain treatment exhibited a notably higher degree of NnV hydrolysis compared to protamex treatment. ACE inhibitory activity was quantified using ACE kit-WST, indicating a substantial inhibitory effect of 76.31% for the papain-digested NnV crude hydrolysate, which was validated by captopril as a positive control. The separation of the NnV-hydrolysate using DEAE sepharose weak-anion-exchange chromatography revealed nine peaks under a 0–1 M NaCl stepwise gradient, with peak no. 3 displaying the highest ACE inhibition of 96%. The further purification of peak no. 3 through ODS-C18 column reverse-phase high-performance liquid chromatography resulted in five sub-peaks (3.1, 3.2, 3.3, 3.4, and 3.5), among which 3.2 exhibited the most significant inhibitory activity of 95.74%. The subsequent analysis of the active peak (3.2) using MALDI–TOF/MS identified two peptides with distinct molecular weights of 896.48 and 1227.651. The peptide sequence determined by MS/MS analysis revealed them as IVGRPLANG and IGDEPRHQYL. The docking studies of the two ACE-inhibitory peptides for ACE molecule demonstrated a binding affinity of −51.4 ± 2.5 and −62.3 ± 3.3 using the HADDOCK scoring function. Full article

(This article belongs to the Special Issue Venoms and Drugs)

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13 pages, 2192 KiB

Open AccessArticle

The Role of the N-Terminal Domain of Thrombomodulin and the Potential of Recombinant Human Thrombomodulin as a Therapeutic Intervention for Shiga Toxin-Induced Hemolytic-Uremic Syndrome

by Sarah Kröller, Jana Schober, Nadine Krieg, Sophie Dennhardt, Wiebke Pirschel, Michael Kiehntopf, Edward M. Conway and Sina M. Coldewey

Toxins 2024, 16(9), 409; https://doi.org/10.3390/toxins16090409 - 20 Sep 2024

Abstract

Hemolytic-uremic syndrome (HUS) is a rare complication of an infection with Shiga toxin (Stx)-producing Escherichia coli (STEC-HUS), characterized by severe acute kidney injury, thrombocytopenia and microangiopathic hemolytic anemia, and specific therapy is still lacking. Thrombomodulin (TM) is a multi-domain transmembrane endothelial cell protein [...] Read more.

Hemolytic-uremic syndrome (HUS) is a rare complication of an infection with Shiga toxin (Stx)-producing Escherichia coli (STEC-HUS), characterized by severe acute kidney injury, thrombocytopenia and microangiopathic hemolytic anemia, and specific therapy is still lacking. Thrombomodulin (TM) is a multi-domain transmembrane endothelial cell protein and its N-terminal domain has been implicated in the pathophysiology of some cases of HUS. Indeed, the administration of recombinant human TM (rhTM) may have efficacy in HUS. We used a Stx-based murine model of HUS to characterize the role of the N-terminal domain of TM. We show that mice lacking that domain (TMLed (−/−)) are more sensitive to Stx, with enhanced HUS progression seen at 4 days and increased mortality at 7 days post-HUS induction. In spite of these changes, renal function was less affected in surviving Stx-challenged TMLed (−/−) mice compared to their wild-type counterparts TMLed (+/+) at 7 days. Contrary to few clinical case reports from Japan, the administration of rhTM (0.06 mg/kg) to wild-type mice (C57BL/6J) with HUS did not protect against disease progression. This overall promising, but also contradictory body of evidence, requires further systematic preclinical and clinical investigations to clarify the role of TM in HUS as a potential therapeutic strategy. Full article

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13 pages, 3348 KiB

Open AccessArticle

The Emerging Fusarium graminearum NA3 Population Produces High Levels of Mycotoxins in Wheat and Barley

by Nicholas A. Rhoades, Susan P. McCormick, Martha M. Vaughan and Guixia Hao

Toxins 2024, 16(9), 408; https://doi.org/10.3390/toxins16090408 - 20 Sep 2024

Abstract

Fusarium graminearum (Fg) is the primary causal agent of Fusarium head blight (FHB) in wheat, barley, and other small grains in North America and worldwide. FHB results in yield reduction and contaminates grain with mycotoxins that pose threats to human and [...] Read more.

Fusarium graminearum (Fg) is the primary causal agent of Fusarium head blight (FHB) in wheat, barley, and other small grains in North America and worldwide. FHB results in yield reduction and contaminates grain with mycotoxins that pose threats to human and livestock health. Three genetically distinct North American (NA) populations of Fg have been characterized, which are generally associated with differences in their predominant trichothecene chemotype: NA1/15-acetyl-deoxynivalenol (15-ADON), NA2/3-acetyl-deoxynivalenol (3-ADON), and NA3/3α-acetoxy, 7,15-dihydroxy-12,13-epoxytrichothec-9-ene (NX-2). Recent studies found that the NA3 population had significantly less spread on point-inoculated wheat spikes than the NA1 and NA2 populations, and NX toxins are important for Fg spread and initial infection in wheat. In this follow-up study, to compare the effect of the three populations on initial infection and mycotoxin production on different hosts, we dip-inoculated spikes of the moderately resistant wheat cultivar Alsen and the susceptible barley cultivar Voyager using five strains from each population to evaluate disease, trichothecene mycotoxin accumulation, and trichothecene production per unit of fungal biomass. In dip-inoculated wheat spikes, the NA3 population produced significantly more trichothecene per unit of fungal biomass and accumulated higher levels of trichothecene per plant biomass than the NA1 and NA2 populations, regardless of the disease levels caused by the three populations. In contrast to its critical role during wheat infection, NX toxins had no effect on barley infection. In dip-inoculated barley, the NA1 population was more infectious and caused more severe FHB symptoms than the NA2 and NA3 populations; however, the NA3 population produced significantly higher toxin per unit of fungal biomass in infected barley tissues than the NA1 population. This study provides critical information on the emerging NA3 population, which produces high levels of NX toxin and poses a potential food safety concern. Full article

(This article belongs to the Section Mycotoxins)

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17 pages, 20060 KiB

Open AccessArticle

Rab4b Promotes Cytolethal Distending Toxin from Glaesserella parasuis-Induced Cytotoxicity in PK-15 Cells

by Yiwen Zhang, Zhen Yang, Ke Dai, Bangdi Hu, Shiyu Xu, Yu Wang, Li Lei, Senyan Du, Qin Zhao, Xiaobo Huang, Rui Wu, Qigui Yan, Yiping Wang, Sanjie Cao and Yiping Wen

Toxins 2024, 16(9), 407; https://doi.org/10.3390/toxins16090407 - 19 Sep 2024

Abstract

Glaesserella parasuis cytolethal distending toxin (GpCDT) can induce cell cycle arrest and apoptosis. Our laboratory’s previous work demonstrated that GTPase 4b (Rab4b) is a key host protein implicated in GpCDT-induced cytotoxicity. This study investigated the probable involvement of Rab4b in [...] Read more.

Glaesserella parasuis cytolethal distending toxin (GpCDT) can induce cell cycle arrest and apoptosis. Our laboratory’s previous work demonstrated that GTPase 4b (Rab4b) is a key host protein implicated in GpCDT-induced cytotoxicity. This study investigated the probable involvement of Rab4b in the process. Our study used CRISPR/Cas9 technology to create a Rab4b-knockout cell line. The results showed greater resistance to GpCDT-induced cell cytotoxicity. In contrast, forced Rab4b overexpression increased GpCDT-induced cytotoxicity. Further immunoprecipitation study reveals that GpCDT may bind with Rab4b. In PK-15 cells, GpCDT is transported to the early endosomes and late endosomes, while after knocking out Rab4b, GpCDT cannot be transported to the early endosome via vesicles. Rab4b appears essential for GpCDT-induced cytotoxicity in PK-15 cells. Full article

(This article belongs to the Section Bacterial Toxins)

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19 pages, 6560 KiB

Open AccessReview

Host Tropism and Structural Biology of ABC Toxin Complexes

by Cole L. Martin, John H. Hill and Stephen G. Aller

Toxins 2024, 16(9), 406; https://doi.org/10.3390/toxins16090406 - 19 Sep 2024

Abstract

ABC toxin complexes are a class of protein toxin translocases comprised of a multimeric assembly of protein subunits. Each subunit displays a unique composition, contributing to the formation of a syringe-like nano-machine with natural cargo carrying, targeting, and translocation capabilities. Many of these [...] Read more.

ABC toxin complexes are a class of protein toxin translocases comprised of a multimeric assembly of protein subunits. Each subunit displays a unique composition, contributing to the formation of a syringe-like nano-machine with natural cargo carrying, targeting, and translocation capabilities. Many of these toxins are insecticidal, drawing increasing interest in agriculture for use as biological pesticides. The A subunit (TcA) is the largest subunit of the complex and contains domains associated with membrane permeation and targeting. The B and C subunits, TcB and TcC, respectively, package into a cocoon-like structure that contains a toxic peptide and are coupled to TcA to form a continuous channel upon final assembly. In this review, we outline the current understanding and gaps in the knowledge pertaining to ABC toxins, highlighting seven published structures of TcAs and how these structures have led to a better understanding of the mechanism of host tropism and toxin translocation. We also highlight similarities and differences between homologues that contribute to variations in host specificity and conformational change. Lastly, we review the biotechnological potential of ABC toxins as both pesticides and cargo-carrying shuttles that enable the transport of peptides into cells. Full article

(This article belongs to the Section Bacterial Toxins)

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20 pages, 3697 KiB

Open AccessArticle

Isolation and Pharmacological Characterisation of Pre-Synaptic Neurotoxins from Thai and Javanese Russell’s Viper (Daboia siamensis) Venoms

by Mimi Lay and Wayne C. Hodgson

Toxins 2024, 16(9), 405; https://doi.org/10.3390/toxins16090405 - 19 Sep 2024

Abstract

The widespread geographical distribution of Russell’s vipers (Daboia spp.) is associated with marked variations in the clinical outcomes of envenoming by species from different countries. This is likely to be due to differences in the quantity and potency of key toxins and, [...] Read more.

The widespread geographical distribution of Russell’s vipers (Daboia spp.) is associated with marked variations in the clinical outcomes of envenoming by species from different countries. This is likely to be due to differences in the quantity and potency of key toxins and, potentially, the presence or absence of some toxins in venoms across the geographical spectrum. In this study, we aimed to isolate and pharmacologically characterise the major neurotoxic components of D. siamensis venoms from Thailand and Java (Indonesia) and explore the efficacy of antivenom and a PLA₂ inhibitor, Varespladib, against the neuromuscular activity. These data will provide insights into the link between venom components and likely clinical outcomes, as well as potential treatment strategies. Venoms were fractionated using RP-HPLC and the in vitro activity of isolated toxins assessed using the chick biventer cervicis nerve-muscle preparation. Two major PLA₂ fractions (i.e., fractions 8 and 10) were isolated from each venom. Fraction 8 from both venoms produced pre-synaptic neurotoxicity and myotoxicity, whereas fraction 10 from both venoms was weakly neurotoxic. The removal of the two fractions from each venom abolished the in vitro neurotoxicity, and partially abolished myotoxicity, of the whole venom. A combination of the two fractions from each venom produced neurotoxic activity that was equivalent to the respective whole venom (10 µg/mL), but the myotoxic effects were not additive. The in vitro neurotoxicity of fraction 8 (100 nM) from each venom was prevented by the pre-administration of Thai Russell’s viper monovalent antivenom (2× recommended concentration) or preincubation with Varespladib (100 nM). Additionally, the neurotoxicity produced by a combination of the two fractions was partially reversed by the addition of Varespladib (100–300 nM) 60 min after the fractions. The present study demonstrates that the in vitro skeletal muscle effects of Thai and Javanese D. siamensis venoms are primarily due to key PLA₂ toxins in each venom. Full article

(This article belongs to the Special Issue Snake Venom: Toxicology and Associated Countermeasures)

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16 pages, 2284 KiB

Open AccessArticle

Enzymatic Hydrolysis of Resorcylic Acid Lactones by an Aeromicrobium sp.

by Shawn J. Hoogstra, Kyle N. Hendricks, David R. McMullin, Justin B. Renaud, Juhi Bora, Mark W. Sumarah and Christopher P. Garnham

Toxins 2024, 16(9), 404; https://doi.org/10.3390/toxins16090404 - 19 Sep 2024

Abstract

Zearalenone and radicicol are resorcylic acid lactones produced by numerous plant pathogenic fungi. Zearalenone is a non-steroidal estrogen mimic that can cause serious reproductive issues in livestock that consume contaminated feed. Radicicol is a potent inhibitor of the molecular chaperone Hsp90, which, in [...] Read more.

Zearalenone and radicicol are resorcylic acid lactones produced by numerous plant pathogenic fungi. Zearalenone is a non-steroidal estrogen mimic that can cause serious reproductive issues in livestock that consume contaminated feed. Radicicol is a potent inhibitor of the molecular chaperone Hsp90, which, in plants, has an important role in coordinating the host’s immune response during infection. Here, we describe the identification and characterization of a soil-borne strain of the Gram-positive bacterium Aeromicrobium sp. capable of hydrolyzing the macrolide ring of resorcylic acid lactones, including zearalenone and radicicol. Proteomic analysis of biochemically enriched fractions from the isolated and cultured bacterium identified an α/β-hydrolase responsible for this activity. A recombinantly expressed and purified form of the hydrolase (termed RALH) was active against both zearalenone and radicicol. Interpretation of high-resolution mass spectrometry and NMR data confirmed the structures of the enzymatic products as the previously reported non-toxic metabolite hydrolyzed zearalenone and hydrolyzed radicicol. Hydrolyzed radicicol was demonstrated to no longer inhibit the ATPase activity of the Saccharomyces cerevisiae Hsp90 homolog in vitro. Enzymatic degradation of resorcylic acid lactones will enable insight into their biological functions. Full article

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17 pages, 3157 KiB

Open AccessArticle

Caffeic Acid Phenethyl Ester Administration Reduces Enterotoxigenic Bacteroides fragilis-Induced Colitis and Tumorigenesis

by Soonjae Hwang, Minjeong Jo, Ju-Eun Hong, Woo-Seung Kim, Da-Hye Kang, Sang-Hyeon Yoo, Kyungsu Kang and Ki-Jong Rhee

Toxins 2024, 16(9), 403; https://doi.org/10.3390/toxins16090403 - 18 Sep 2024

Abstract

The human colonic commensal enterotoxigenic Bacteroides fragilis (ETBF) is associated with chronic colitis and colon cancer. ETBF colonization induces colitis via the Bacteroides fragilis toxin (BFT). BFT secreted by ETBF cause colon inflammation via E-cadherin cleavage/NF-κB signaling. ETBF promotes colon tumorigenesis via interleukin [...] Read more.

The human colonic commensal enterotoxigenic Bacteroides fragilis (ETBF) is associated with chronic colitis and colon cancer. ETBF colonization induces colitis via the Bacteroides fragilis toxin (BFT). BFT secreted by ETBF cause colon inflammation via E-cadherin cleavage/NF-κB signaling. ETBF promotes colon tumorigenesis via interleukin 17A (IL-17A)/CXCL-dependent inflammation, but its bioactive therapeutics in ETBF-promoted tumorigenesis remain unexplored. In the current study, we investigated the caffeic acid phenethyl ester (CAPE) in the murine model of ETBF colitis and tumorigenesis. In this study, we observed that CAPE treatment mitigated inflammation induced by ETBF in mice. Additionally, our findings indicate that CAPE treatment offers protective effects against ETBF-enhanced colon tumorigenesis in a mouse model of colitis-associated colon cancer induced by azoxymethane (AOM) and dextran sulfate sodium. Notably, the decrease in colon tumorigenesis following CAPE administration correlates with a reduction in the expression of IL-17A and CXCL1 in the gastrointestinal tract. The molecular mechanism for CAPE-induced protection against ETBF-mediated tumorigenesis is mediated by IL-17A/CXCL1, and by NF-κB activity in intestinal epithelial cells. Our findings indicate that CAPE may serve as a preventive agent against the development of ETBF-induced colitis and colorectal cancer (CRC). Full article

(This article belongs to the Section Bacterial Toxins)

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21 pages, 4548 KiB

Open AccessArticle

Exposure of Cattle Breeding Herds to Naturally Co-Contaminated Zearalenone and Deoxynivalenol: The Relevance of a Urinary Mycotoxin Monitoring System for Herd Health and Food Safety

by Oky Setyo Widodo, Seiichi Uno, Emiko Kokushi, Osamu Yamato, M. Fariz Fadillah Mardianto, Urara Shinya, Yuto Kano, Chiho Kawashima, Yasuo Fushimi, Tetsushi Ono, Masayasu Taniguchi and Mitsuhiro Takagi

Toxins 2024, 16(9), 402; https://doi.org/10.3390/toxins16090402 - 18 Sep 2024

Abstract

The widespread presence of Fusarium mycotoxins in animal feed is a global issue, not only for the health of livestock but also for ensure the safety of food as an end product. High concentrations of zearalenone (ZEN) and deoxynivalenol (DON) have been detected [...] Read more.

The widespread presence of Fusarium mycotoxins in animal feed is a global issue, not only for the health of livestock but also for ensure the safety of food as an end product. High concentrations of zearalenone (ZEN) and deoxynivalenol (DON) have been detected in the diets of Japanese Black (JB) and Holstein Friesian (HF) breeding herds. Consequently, we monitored serum biochemical parameters over a long time in both herds, focusing on anti-Müllerian hormone (AMH) levels and acute-phase inflammation. Additionally, urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) and progesterone levels were measured in the HF herd. The JB herd, a ZEN-dominant model with low DON contamination, demonstrated ZEN levels that exceeded the Japanese limit in the purchased total mixed rations (TMR). Conversely, the HF herd, which primary consumes DON-dominant feed with low ZEN contamination, had high DON levels in the dent corn silage. Specifically, the JB herd’s TMR contained 1.79 mg/kg ZEN and 0.58 mg/kg DON, whereas the HF herd’s silage had 15.3 mg/kg DON (dried sample) and 0.1 mg/kg ZEN. Enzyme-linked immunoassay were used to measure urinary ZEN-DON levels following confirmation through liquid chromatography-tandem mass spectrometry. Urinary ZEN-DON levels measured were significantly correlated (p < 0.05, r > 0.6) in both herds. In the HF herd, AMH levels increased (p = 0.01) and serum amyloid A (SAA) levels decreased (p = 0.02) when contaminated and at the end of the monitoring period. Additionally, urinary ZEN and DON levels were significantly correlated with SAA levels (ZEN: p = 0.00, r = 0.46; DON: p = 0.03, r = 0.33), with an increase in ZEN and DON levels resulting in higher SAA levels. The JB herd showed no significant differences. Additionally, in the HF herd, 8-OHdG/Cre levels increased significantly during major contamination periods (p < 0.05). Clinical data from the HF herd indicated an increase in mastitis cases and treatment rates during periods of major contamination. Abortion rates in the HF herd decreased from 22.9% (before monitoring) to 8.9% (during the high contamination period) and finally to 1% (at the end of the monitoring period), with corresponding increases in progesterone levels. ZEN-DON contamination adversely affects breeding cattle’s productivity, reproductive performance, and health. Therefore, monitoring urinary ZEN-DON is valuable for detecting contaminants and ensuring the safety of food products. Full article

(This article belongs to the Special Issue Toxicity Assessment, Rapid Detection and Control of Foodborne Mycotoxins: Advances and Prospects)

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15 pages, 7210 KiB

Open AccessArticle

Astaxanthin Alleviates Hepatic Lipid Metabolic Dysregulation Induced by Microcystin-LR

by Qinmei Tan, Hanyu Chu, Jia Wei, Sisi Yan, Xiaoya Sun, Jiangping Wang, Lemei Zhu and Fei Yang

Toxins 2024, 16(9), 401; https://doi.org/10.3390/toxins16090401 - 18 Sep 2024

Abstract

Microcystin-LR (MC-LR), frequently generated by cyanobacteria, has been demonstrated to raise the likelihood of liver disease. Few previous studies have explored the potential antagonist against MC-LR. Astaxanthin (ASX) has been shown to possess various beneficial effects in regulating lipid metabolism in the liver. [...] Read more.

Microcystin-LR (MC-LR), frequently generated by cyanobacteria, has been demonstrated to raise the likelihood of liver disease. Few previous studies have explored the potential antagonist against MC-LR. Astaxanthin (ASX) has been shown to possess various beneficial effects in regulating lipid metabolism in the liver. However, whether ASX could alleviate MC-LR-induced hepatic lipid metabolic dysregulation is as yet unclear. In this work, the important roles and mechanisms of ASX in countering MC-LR-induced liver damage and lipid metabolic dysregulation were explored for the first time. The findings revealed that ASX not only prevented weight loss but also enhanced liver health after MC-LR exposure. Moreover, ASX effectively decreased triglyceride, total cholesterol, aspartate transaminase, and alanine aminotransferase contents in mice that were elevated by MC-LR. Histological observation showed that ASX significantly alleviated lipid accumulation and inflammation induced by MC-LR. Mechanically, ASX could significantly diminish the expression of genes responsible for lipid generation (Srebp-1c, Fasn, Cd36, Scd1, Dgat1, and Pparg), which probably reduced lipid accumulation induced by MC-LR. Analogously, MC-LR increased intracellular lipid deposition in THLE-3 cells, while ASX decreased these symptoms by down-regulating the expression of key genes in the lipid synthesis pathway. Our results implied that ASX played a crucial part in lipid synthesis and effectively alleviated MC-LR-induced lipid metabolism dysregulation. ASX might be developed as a novel protectant against hepatic impairment and lipid metabolic dysregulation associated with MC-LR. This study offers new insights for further management of MC-LR-related metabolic diseases. Full article

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19 pages, 6017 KiB

Open AccessArticle

The Contrasting Effects of Bothrops lanceolatus and Bothrops atrox Venom on Procoagulant Activity and Thrombus Stability under Blood Flow Conditions

by Fatima Radouani, Prisca Jalta, Caroline Rapon, Chloe Lezin, Chelsea Branford, Jonathan Florentin, Jose Maria Gutierrez, Dabor Resiere, Remi Neviere and Olivier Pierre-Louis

Toxins 2024, 16(9), 400; https://doi.org/10.3390/toxins16090400 - 18 Sep 2024

Abstract

Background: Consumption coagulopathy and hemorrhagic syndrome are the typical features of Bothrops sp. snake envenoming. In contrast, B. lanceolatus envenoming can induce thrombotic complications. Our aim was to test whether crude B. lanceolatus and B. atrox venoms would display procoagulant activity and induce [...] Read more.

Background: Consumption coagulopathy and hemorrhagic syndrome are the typical features of Bothrops sp. snake envenoming. In contrast, B. lanceolatus envenoming can induce thrombotic complications. Our aim was to test whether crude B. lanceolatus and B. atrox venoms would display procoagulant activity and induce thrombus formation under flow conditions. Methods and Principal Findings: Fibrin formation in human plasma was observed for B. lanceolatus venom at 250–1000 ng/mL concentrations, which also induced clot formation in purified human fibrinogen, indicating thrombin-like activity. The degradation of fibrinogen confirmed the fibrinogenolytic activity of B. lanceolatus venom. B. lanceolatus venom displayed consistent thrombin-like and kallikrein-like activity increases in plasma conditions. The well-known procoagulant B. atrox venom activated plasmatic coagulation factors in vitro and induced firm thrombus formation under high shear rate conditions. In contrast, B. lanceolatus venom induced the formation of fragile thrombi that could not resist shear stress. Conclusions: Our results suggest that crude B. lanceolatus venom displays amidolytic activity and can activate the coagulation cascade, leading to prothrombin activation. B. lanceolatus venom induces the formation of an unstable thrombus under flow conditions, which can be prevented by the specific monovalent antivenom Bothrofav^®. Full article

(This article belongs to the Section Animal Venoms)

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14 pages, 2179 KiB

Open AccessArticle

Transcriptomic Analysis Reveals Diverse Expression of Scorpion Toxin Genes in Mesobuthus martensii

by Zhongxian Yang, Haiquan Wang, Yan Zhao, Jianyu Huang, Chao Zhang and Zhiyong Di

Toxins 2024, 16(9), 399; https://doi.org/10.3390/toxins16090399 - 18 Sep 2024

Abstract

Scorpions, an ancient group of venomous invertebrates, have existed for over 430 million years. Their toxins, important for predation and defense, exhibit a variety of biological and pharmacological activities. Research on scorpion toxins has spanned decades. Notably, the toxin genes of Mesobuthus martensii [...] Read more.

Scorpions, an ancient group of venomous invertebrates, have existed for over 430 million years. Their toxins, important for predation and defense, exhibit a variety of biological and pharmacological activities. Research on scorpion toxins has spanned decades. Notably, the toxin genes of Mesobuthus martensii (Scorpiones: Buthidae), a well-known Chinese herbal medicine, have been described at genomic and proteomic levels. However, previous studies primarily focused on the toxin genes expressed in the venom glands, overlooking their expression in multiple tissues. This study analyzed transcriptomes from 14 tissues of M. martensii. Gene annotation revealed 83 toxin and toxin-like genes, including those affecting sodium, potassium, calcium, and chloride ion channels. Approximately 70% of toxin genes were highly expressed in the vesicle; additionally, some exhibited low or no expression in the vesicle while showing high expression in other tissues. Beyond the vesicle, high expression levels of toxin genes were observed in metasoma segments II-V, blood, lateral eyes, chelicerae, legs, pedipalp chelae, femurs, and patellae. This expression pattern suggests that toxin genes are recruited from multiple tissues and may help prevent intraspecific harm during courtship and competition for prey. These findings inspire further research into the evolutionary recruitment process of scorpion toxins. Full article

(This article belongs to the Special Issue Animal Venoms: Unraveling the Molecular Complexity (2nd Edition))

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15 pages, 2308 KiB

Open AccessArticle

Thermoregulation Effects of Phoneutria nigriventer Isolated Toxins in Rats

by Carla Bogri Butkeraitis, Monica Viviana Abreu Falla and Ivo Lebrun

Toxins 2024, 16(9), 398; https://doi.org/10.3390/toxins16090398 - 18 Sep 2024

Abstract

Body temperature is primarily regulated by the hypothalamus, ensuring proper metabolic function. Envenomation by Phoneutria nigriventer can cause symptoms such as hypothermia, hyperthermia, sweating, and shivering, all related to thermoregulation. This study aims to analyze and identify components of the venom that affect [...] Read more.

Body temperature is primarily regulated by the hypothalamus, ensuring proper metabolic function. Envenomation by Phoneutria nigriventer can cause symptoms such as hypothermia, hyperthermia, sweating, and shivering, all related to thermoregulation. This study aims to analyze and identify components of the venom that affect thermoregulation and to evaluate possible mechanisms. Rats were used for thermoregulation analysis, venom fractionation by gel filtration and reverse-phase chromatography (C18), and sequencing by Edman degradation. The venom exhibited hypothermic effects in rats, while its fractions demonstrated both hypothermic (pool II) and hyperthermic (pool III) effects. Further separations of the pools with C18 identified specific peaks responsible for these effects. However, as the peaks were further purified, their effects became less significant. Tests on U87 human glioblastoma cells showed no toxicity. Sequencing of the most active peaks revealed masses similar to those of the Tachykinin and Ctenotoxin families, both known to act on the nervous system. The study concludes that molecules derived from venom can act synergistically or antagonistically. Additionally, toxins that affect thermoregulation are poorly studied and require further characterization. These toxins could potentially serve as sources for the development of new thermoregulatory drugs. Full article

(This article belongs to the Special Issue New Insights into Structure and Function of Arthropod Toxins and Other Toxins: Tribute to Professor Hervé Rochat)

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13 pages, 1369 KiB

Open AccessArticle

Global Perspectives on Mycotoxin Reference Materials (Part I): Insights from Multi-Supplier Comparison Study Including Aflatoxin B1, Deoxynivalenol and Zearalenone

by David Steiner, Tibor Bartók, Michael Sulyok, András Szekeres, Mónika Varga, Levente Horváth and Helmut Rost

Toxins 2024, 16(9), 397; https://doi.org/10.3390/toxins16090397 - 17 Sep 2024

Abstract

We conducted a comprehensive examination of liquid mycotoxin reference standards. A total of 30 different standards were tested, each containing 10 samples of three distinct substances: Aflatoxin B1, Deoxynivalenol, and Zearalenone. The standards were sourced from 10 different global market leading manufacturers. To [...] Read more.

We conducted a comprehensive examination of liquid mycotoxin reference standards. A total of 30 different standards were tested, each containing 10 samples of three distinct substances: Aflatoxin B1, Deoxynivalenol, and Zearalenone. The standards were sourced from 10 different global market leading manufacturers. To facilitate comparison, all the standard sets were adjusted to the same concentration level. The standards were analyzed using the techniques LC-MS/MS, HPLC-DAD, and LC-HRMS to assess their quality attributes. Regarding the validation of the reference values, it was observed that 30% of the suppliers provided reference standards that were either below the lower acceptance limit or above the higher acceptance limit, confirmed by both the LC-MS/MS and HPLC-DAD methods. Furthermore, a total of 12 impurities were found in the DON standards, 10 in the AFB₁ standards, and 8 in the ZON standards, distributed across all the suppliers. Therefore, this study suggests relevant adjustments to the ISO 17034 standard, proposing that the purity of a raw material should be uniformly based on q-NMR analysis, as most manufacturers state the purity of their certificates is determined using HPLC-UV or LC-MS/MS. Liquid standards with a shelf life of ≤1 year should not exceed an uncertainty of 3%. Standards that have a longer shelf life should not have more than 5% uncertainty. This study also emphasizes the importance of stability. The standards should undergo continuous long-term monitoring; otherwise, products may exhibit a target value of only 80%, as seen in one instance. It is also recommended to include proof of HPLC and LC-MS/MS analyses on the certificate of each released batch of a final product. Full article

(This article belongs to the Section Mycotoxins)

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