Toxins and Venoms

An evaluation of the genotoxicity and 90-day repeated dose oral toxicity in rats of Porphyridium purpureum

Interest in microalgae products for use in food is increasing, as demands for sustainable and cost-effective food choices grow due to the escalating global population and increase in climate-related struggles with agriculture. Toxicological assessments of some species of microalgae have been conducted, but there were little data available for the oral consumption of the red microalgae Porphyridium purpureum and no data on genotoxicity. This article articulates a genotoxicity assessment and a 90-day repeated dose oral toxicity study in rats performed according to OECD guidelines. Under the experimental conditions applied, the test item did not induce gene mutations by base pair changes or frameshifts in the genome of the strains used in the bacterial reverse mutation test. Similarly, the test item did not induce structural chromosomal aberrations in V79 hamster lung cells. The test item also did not cause chromosomal damage in bone marrow of mice in the mammalian micronucleus test. The no observed adverse effect level (NOAEL) of the 90-day repeated dose oral toxicity study in rats was determined to be the highest dose tested, 3000 mg/kg bw/day. These data add to the body of evidence regarding the safety of P. purpureum for human consumption.

Bio-barcode assay: A useful technology for ultrasensitive and logic-controlled specific detection in food safety: A review

Food safety is one of the greatest public health challenges. Developing ultrasensitive detection methods for analytes at ultra-trace levels is, therefore, essential. In recent years, the bio-barcode assay (BCA) has emerged as an effective ultrasensitive detection strategy that is based on the indirect amplification of various DNA probes. This review systematically summarizes the progress of fluorescence, PCR, and colorimetry-based BCA methods for the detection of various contaminants, including pathogenic bacteria, toxins, pesticides, antibiotics, and other chemical substances in food in over 120 research papers. Current challenges, including long experimental times and strict storage conditions, and the prospects for the application of BCA in biomedicine and environmental analyses, have also been discussed herein.

Transcriptome Analysis Reveals the Genes Involved in Oxidative Stress Responses of Scallop to PST-Producing Algae and a Candidate Biomarker for PST Monitoring

Paralytic shellfish toxins (PST) could be accumulated in bivalves and cause safety problems. To protect public health, bivalves are examined for PST contamination before entering the market, usually by high-performance liquid chromatography (HPLC) or LC-tandem mass spectrometry (LC-MS/MS) in the lab, which needs PST standards not all available and is time-consuming for large sample sizes. To detect PST toxicity in bivalves rapidly and sensitively, a biomarker gene is highly demanded, but the related study is very limited. In this study, we fed a commercially important bivalve, Patinopecten yessoensis, with the PST-producing dinoflagellate Alexandrium catenella. After 1, 3, and 5 days of exposure, both PST concentrations and toxicity levels in the digestive gland continuously increased. Transcriptome analysis revealed that the differentially expressed genes were significantly enriched in oxidation-reduction process, which included the cytochrome P450 genes (CYPs), type I iodothyronine deiodinase (IOD1s), peroxidasin (PXDN), and acyl-Coenzyme A oxidase 1 (ACOX1) at day 1 and a superoxide dismutase (SOD) at day 5, highlighting the crucial roles of these genes in response to oxidative stress induced by PST. Among the 33 continuously upregulated genes, five showed a significant correlation between gene expression and PST concentration, with the highest correlation present in PyC1QL4-1, the gene encoding Complement C1Q-like protein 4, C1QL4. In addition, the correlation between PyC1QL4-1 expression and PST toxicity was also the highest. Further analysis in another aquaculture scallop (Chlamys farreri) indicated that the expression of CfC1QL4-1, the homolog of PyC1QL4-1, also exhibited significant correlations with both PST toxicity and concentration. Our results reveal the gene expression responses of scallop digestive glands to PST-producing algae and indicate that the C1QL4-1 gene might be a potential biomarker for PST monitoring in scallops, which may provide a convenient way for the early warning and sensitive detection of PST contamination in the bivalves.

The application of genome-wide CRISPR-Cas9 screens to dissect the molecular mechanisms of toxins

Many toxins are life-threatening to both animals and humans. However, specific antidotes are not available for most of those toxins. The molecular mechanisms underlying the toxicology of well-known toxins are not yet fully characterized. Recently, the advance in CRISPR-Cas9 technologies has greatly accelerated the process of revealing the toxic mechanisms of some common toxins on hosts from a genome-wide perspective. The high-throughput CRISPR screen has made it feasible to untangle complicated interactions between a particular toxin and its corresponding targeting tissue(s). In this review, we present an overview of recent advances in molecular dissection of toxins’ cytotoxicity by using genome-wide CRISPR screens, summarize the components essential for toxin-specific CRISPR screens, and propose new strategies for future research.

HPLC-DAD Analysis of Hemp Oil Supplements for Determination of Four Cannabinoids: Cannabidiol, Cannabidiolic Acid, Cannabinol and Delta 9-Tetrahydrocannabinol

Growing consumer interest in hemp oilseed supplements requires quality control. Therefore, appropriate, effective and verified analytical methods are needed for the determination of some bioactive cannabinoids in them. The aim of the study is to present an extended (compared to our previous research) validated high performance liquid chromatography with diode array detection (HPLC-DAD) method for the determination of four cannabinoids (cannabidiol, cannabidiolic acid, cannabinol and delta-9-tetrahydrocannabinol) in an oil matrix, which was used to determine these cannabinoids in seven commercial hemp oil supplements. In our method, the isolation of the target compounds was based on liquid extraction with acetonitrile combined with the freezing (at −41 °C) of the oil phase. The results show that in some cases, the determined concentrations of cannabinoids in the tested supplements differ significantly from those declared by the manufacturers. As for the main medicinal cannabinoid (CBD) in hemp oil supplements, in two cases, the measured concentration was significantly lower (1.45 and 1.81%) than the declared (5 and 5%), and in the other supplements, the obtained results confirm the declared amount of CBD within the error range from 3.29 to 9.2%. Therefore, to ensure the safe and beneficial use of these supplements by consumers, it is necessary to monitor their cannabinoid composition.

In Vitro Effects of Papaverine on Cell Proliferation, Reactive Oxygen Species, and Cell Cycle Progression in Cancer Cells

Papaverine (PPV) is an alkaloid isolated from the Papaver somniferum. Research has shown that PPV inhibits proliferation. However, several questions remain regarding the effects of PPV in tumorigenic cells. In this study, the influence of PPV was investigated on the proliferation (spectrophotometry), morphology (light microscopy), oxidative stress (fluorescent microscopy), and cell cycle progression (flow cytometry) in MDA-MB-231, A549, and DU145 cell lines. Exposure to 150 μM PPV resulted in time- and dose-dependent antiproliferative activity with reduced cell growth to 56%, 53%, and 64% in the MDA-MB-231, A549, and DU145 cell lines, respectively. Light microscopy revealed that PPV exposure increased cellular protrusions in MDA-MB-231 and A549 cells to 34% and 23%. Hydrogen peroxide production increased to 1.04-, 1.02-, and 1.44-fold in PPV-treated MDA-MB-231, A549, and DU145 cells, respectively, compared to cells propagated in growth medium. Furthermore, exposure to PPV resulted in an increase of cells in the sub-G₁ phase by 46% and endoreduplication by 10% compared to cells propagated in growth medium that presented with 2.8% cells in the sub-G₁ phase and less than 1% in endoreduplication. The results of this study contribute to understanding of effects of PPV on cancer cell lines.

Electroanalytical Overview: Electrochemical Sensing Platforms for Food and Drink Safety

Robust, reliable, and affordable analytical techniques are essential for screening and monitoring food and water safety from contaminants, pathogens, and allergens that might be harmful upon consumption. Recent advances in decentralised, miniaturised, and rapid tests for health and environmental monitoring can provide an alternative solution to the classic laboratory-based analytical techniques currently utilised. Electrochemical biosensors offer a promising option as portable sensing platforms to expedite the transition from laboratory benchtop to on-site analysis. A plethora of electroanalytical sensor platforms have been produced for the detection of small molecules, proteins, and microorganisms vital to ensuring food and drink safety. These utilise various recognition systems, from direct electrochemical redox processes to biological recognition elements such as antibodies, enzymes, and aptamers; however, further exploration needs to be carried out, with many systems requiring validation against standard benchtop laboratory-based techniques to offer increased confidence in the sensing platforms. This short review demonstrates that electroanalytical biosensors already offer a sensitive, fast, and low-cost sensor platform for food and drink safety monitoring. With continued research into the development of these sensors, increased confidence in the safety of food and drink products for manufacturers, policy makers, and end users will result.

Evaluation of Electrocardiographic Parameters and the Presence of Interatrial Block in Patients with Mad Honey Intoxication

Mad honey intoxication (MHI) is a food-induced clinical condition that usually presents with cardiovascular symptoms and can lead to life-threatening arrhythmias if not diagnosed and treated early. No data exist in the literature on the presence of interatrial block (IAB) after food intoxication. In our study, we sought to investigate atrioventricular electrocardiography (ECG) parameters and determine the frequency of IAB in patients with MHI. In total, 76 patients diagnosed with MHI were included in our retrospective study. Twelve-lead ECGs were performed and participants were divided into two groups according to the presence of IAB in the reference ECG. The P maximum (P_max), P minimum (P_min), P dispersion (P_disp), T peak to T end (Tp-Te) interval and QT dispersion (QT_disp) values were compared between the two groups. IAB was detected in 28 (35.5%) of 76 MHI patients included in the final analysis. P_max duration (122 ± 8; p < 0.001) and PD (69 ± 11; p < 0.001) were significantly higher in the IAB ( +) group. During regression analysis, P_max [odds ratio (OR) 1.158, 95% confidence interval (CI) 1.036-1.294; p = 0.010] and Pd (OR 1.086, 95% CI 1.001-1.017; p = 0.046) were independently associated with IAB. P_max and Pd area under the receiver operating characteristic curve values for IAB prediction were 0.926 (95% CI 0.841-1,000; p < 0.001) and 0.872 (95% CI 0.765-0.974; p < 0.001), respectively. ECG changes are common in patients presenting with MHI. These patients need to be followed up clinically in terms of progression to arrhythmic events that may occur in the future.

Advances in nanomaterial-based electrochemical biosensors for the detection of microbial toxins, pathogenic bacteria in food matrices

There is a growing demand to protect food products against the hazard of microbes and their toxins. To satisfy such goals, it is important to develop highly sensitive, reliable, sophisticated, rapid, and cost-effective sensing techniques such as electrochemical sensors/biosensors. Although diverse forms of nanomaterials (NMs)-based electrochemical sensing methods have been introduced in markets, the reliability of commercial products is yet insufficient to meet the practical goal. In this review, we focused on: 1) sources of pathogenic microbes and their toxins; 2) possible routes of their entrainment in food, and 3) current development of NM-based biosensors to realize real-time detection of the target analytes. At last, future prospects and challenges in this research field are discussed.

Possibilities Of Correcting Iatrogenic Mucositis With Cyanides In Experiment

Background — Radiation and chemotherapy of cancer cause complications that drastically reduce the quality of life. This requires the search for effective therapeutic agents for the mucositis treatment. We investigated the effects of amygdalin as a trophic external agent for post-radiation and post-chemotherapeutic oral mucositides. The study objectives were to conduct an immunomorphological analysis using an experimental model of iatrogenic mucositis, and to evaluate the effectiveness of amygdalin as cyanide with probable protective chemical properties in mucositis correction. Material and Methods — Our studies were performed on 40 male white rats. Radiation therapy was simulated by irradiating animals with a cranial dose of 6 Gy. Then an intraperitoneal injection of cisplatin was performed. On day 7, a biopsy was taken (model control), and animals were treated for 14 days with a mixture of 0.02% nitrofurazone, Desensitin® gel, Suprasorb® and amygdalin, after which a biopsy was taken again (therapy control). Results — Immunomorphological studies revealed dystrophic structural changes due to the progress of tissue hypoxia and the launch of Fas-dependent apoptosis in tissues. Using treatment with amygdalin by activating hypoxia-inducible factor (HIF) stimulates the macrophage population to remodel the stroma of the submucosal layer. In addition to activating the cellular components of local immunity, a therapeutic anti-apoptotic effect has been established. Conclusion — The method of mucositis correction by amygdalin is effective, which is confirmed by increased proliferation and decreased apoptosis due to revascularization and hypoxia reduction.

Allelopathic inhibitory effect of the macroalga Pyropia haitanensis (Rhodophyta) on harmful bloom-forming Pseudo-nitzschia species

The blooms of harmful microalgae represent a prominent threat to fisheries, public health, and economies throughout the world. Recent studies have shown that certain macroalgae release allelochemicals that can inhibit the growth of bloom-forming microalgae. In this study, we found that the macroalga Pyropia haitanensis significantly inhibited growth of the harmful bloom-forming microalgae Pseudo-nitzschia pungens and Pseudo-nitzschia multiseries. The inhibitory-effect of the live thali of P. haitanensis was highest, followed by that of dry powder, water-soluble extract, and culture medium filtrate. The Pseudo-nitzschia species died 96 h after exposure to 5-10 g fresh-weight L^-1 of P. haitanensis live thalli. Furthermore, an aqueous extract of P. haitanensis suppressed the growth of P. pungens and P. multiseries, thereby indicating that P. haitanensis contains stable allelopathic substances that cause the observed inhibitory-effects. On the basis of these findings, we conclude that the macroalga P. haitanensis would have potential utility in controlling the blooms of Pseudo-nitzschia species.

Toxicity and Anticancer Potential of Karwinskia: A Review

Karwinskia genus consists of shrubs and small trees. Four toxic compounds have been isolated from Karwinskia plants, which were typified as dimeric anthracenones and named T496, T514, T516, and T544. Moreover, several related compounds have been isolated and characterized. Here we review the toxicity of the fruit of Karwinskia plants when ingested (accidentally or experimentally), as well as the toxicity of its isolated compounds. Additionally, we analyze the probable antineoplastic effect of T514. Toxins cause damage mainly to nervous system, liver, lung, and kidney. The pathophysiological mechanism has not been fully understood but includes metabolic and structural alterations that can lead cells to apoptosis or necrosis. T514 has shown selective toxicity in vitro against human cancer cells. T514 causes selective and irreversible damage to peroxisomes; for this reason, it was renamed peroxisomicine A1 (PA1). Since a significant number of malignant cell types contain fewer peroxisomes than normal cells, tumor cells would be more easily destroyed by PA1 than healthy cells. Inhibition of topoisomerase II has also been suggested to play a role in the effect of PA1 on malignant cells. More research is needed, but the evidence obtained so far indicates that PA1 could be an effective anticancer agent.

Confirmatory non-invasive and non-destructive identification of poison ivy using a hand-held Raman spectrometer

Poison ivy (Toxicodendron radicans) is a forest understory plant that grows throughout the United States, Canada and Mexico. The plant contains urushiol oils, a mixture of pentadecylcatechols, that cause severe allergic reactions on skin including reddish inflammation, uncoloured bumps and blistering. Such allergic reactions develop within hours or days, which facilitates unknowing spread of the urushiol inside the house. This enables continuous contact with urushiol extending the length of time of the rash. It should be noted that apart from extensive washing with soap and cold water, there is no direct way to treat urushiol-induced allergic reactions. In these circumstances, the best practice is to avoid contact with the plant. However, differentiating poison ivy from other plants requires sophisticated botanical experience that is not possessed by a vast majority of people. To overcome this limitation, we developed a confirmatory, label-free, non-invasive and non-destructive approach for detection and identification of poison ivy. We show that using a hand-held Raman spectrometer, 100% accurate identification of this species can be performed in only one second. We also demonstrate that in combination with partial least square discriminant analysis (PLS-DA), Raman spectroscopy is capable of distinguishing poison ivy from more than fifteen different plant species, including weeds, grasses and trees. The use of a hand-held spectrometer on a motorized robotic platform or an unmanned aerial vehicle (UAV) can be used for automated surveillance of household and agricultural spaces enabling confirmatory detection and identification of this dangerous plant species.

Poison ivy (Toxicodendron radicans) is a noxious weed that grows throughout North America and induces terrible rashes on contact. Using a portable Raman device, we identified these plants and differentiated them from other species with high accuracy.

Relationships Between Chemical Defenses of Common Toad (Bufo bufo) Tadpoles and Bacterial Community Structure of their Natural Aquatic Habitat

Many organisms synthesize secondary metabolites against natural enemies. However, to which environmental factors the production of these metabolites is adjusted to is poorly investigated in animals, especially so in vertebrates. Bufadienolides are steroidal compounds that are present in a wide range of plants and animals and, if present in large quantities, can provide protection against natural enemies, such as pathogens. In a correlative study involving 16 natural populations we investigated how variation in bufadienolide content of larval common toads (Bufo bufo) is associated with the bacterial community structure of their aquatic environment. We also evaluated pond size, macrovegetation cover, and the abundance of predators, conspecifics and other larval amphibians. We measured toxin content of tadpoles using HPLC-MS and determined the number of bufadienolide compounds (NBC) and the total quantity of bufadienolides (TBQ). AICc-based model selection revealed strong relationships of NBC and TBQ with bacterial community structure of the aquatic habitat as well as with the presence of conspecific tadpoles. The observed relationships may have arisen due to adaptation to local bacterial communities, phenotypic plasticity, differential biotransformation of toxin compounds by different bacterial communities, or a combination of these processes. Bacterial groups that contribute to among-population variation in toxin content remain to be pinpointed, but our study suggesting that toxin production may be influenced by the bacterial community of the environment represents an important step towards understanding the ecological and evolutionary processes leading to microbiota-mediated variation in skin toxin profiles of aquatic vertebrates.

The skin microbiome facilitates adaptive tetrodotoxin production in poisonous newts

Rough-skinned newts (Taricha granulosa) use tetrodotoxin (TTX) to block voltage-gated sodium (Nav) channels as a chemical defense against predation. Interestingly, newts exhibit extreme population-level variation in toxicity attributed to a coevolutionary arms race with TTX-resistant predatory snakes, but the source of TTX in newts is unknown. Here, we investigated whether symbiotic bacteria isolated from toxic newts could produce TTX. We characterized the skin-associated microbiota from a toxic and non-toxic population of newts and established pure cultures of isolated bacterial symbionts from toxic newts. We then screened bacterial culture media for TTX using LC-MS/MS and identified TTX-producing bacterial strains from four genera, including Aeromonas, Pseudomonas, Shewanella, and Sphingopyxis. Additionally, we sequenced the Nav channel gene family in toxic newts and found that newts expressed Nav channels with modified TTX binding sites, conferring extreme physiological resistance to TTX. This study highlights the complex interactions among adaptive physiology, animal-bacterial symbiosis, and ecological context.

Transcriptomic Analysis of Pseudoscorpion Venom Reveals a Unique Cocktail Dominated by Enzymes and Protease Inhibitors

Transcriptomic and genomic analyses have illuminated the diversity of venoms in three of the four venomous arachnid orders (scorpions, spiders, and ticks). To date, no venom gland transcriptome analysis has been available for pseudoscorpions, the fourth venomous arachnid lineage. To redress this gap, we sequenced an mRNA library generated from the venom glands of the species Synsphyronus apimelus (Garypidae). High-throughput sequencing by the Illumina protocol, followed by de novo assembly, resulted in a total of 238,331 transcripts. From those, we annotated 131 transcripts, which code for putative peptides/proteins with similar sequences to previously reported venom components available from different arachnid species in protein databases. Transcripts putatively coding for enzymes showed the richest diversity, followed by other venom components such as peptidase inhibitors, cysteine-rich peptides, and thyroglobulin 1-like peptides. Only 11 transcripts were found that code for putatively low molecular mass spider toxins. This study constitutes the first report of the diversity of components within pseudoscorpion venom.

A proposed resolution to the paradox of drug reward: Dopamine's evolution from an aversive signal to a facilitator of drug reward via negative reinforcement

The mystery surrounding how plant neurotoxins came to possess reinforcing properties is termed the paradox of drug reward. Here we propose a resolution to this paradox whereby dopamine - which has traditionally been viewed as a signal of reward - initially signaled aversion and encouraged escape. We suggest that after being consumed, plant neurotoxins such as nicotine activated an aversive dopaminergic pathway, thereby deterring predatory herbivores. Later evolutionary events - including the development of a GABAergic system capable of modulating dopaminergic activity - led to the ability to down-regulate and 'control' this dopamine-based aversion. We speculate that this negative reinforcement system evolved so that animals could suppress aversive states such as hunger in order to attend to other internal drives (such as mating and shelter) that would result in improved organismal fitness.

Melittin-glutathione S-transferase fusion protein exhibits anti-inflammatory properties and minimal toxicity

Although potent, proteins often require chemical modification for therapeutic use. Immunogenicity, difficult synthesis, and scale-up of these modifications are all engineering obstacles that stand in the way of expanding the use of these therapeutics. Melittin, a peptide derived from bee venom, has been shown to modulate inflammation. Although potentially therapeutic, the native peptide causes cell lysis and toxicity significantly hindering therapeutic application. Based upon the knowledge of the pore formation mechanism, we examined the toxicity and therapeutic effect of a melittin fusion protein with glutathione-S-transferase. The fusion of melittin and glutathione S-transferase results in diminished toxicity of the peptide and retained anti-inflammatory properties at doses that exceed toxic concentration of native melittin. Our results suggest that fusion proteins, particularly those of glutathione-S-transferase, may be facile modifications to control protein activity.

Cloning and molecular characterization of scorpion Buthus martensi venom hyaluronidases: a novel full-length and diversiform noncoding isoforms

Hyaluronidase is a common component of scorpion venom and has been considered as "spreading factor" that promotes a fast penetration of the venom in the anaphylactic reaction. In the current study, a novel full-length of hyaluronidase BmHYI and three noncoding isoforms of BmHYII, BmHYIII and BmHYIV were cloned by using a combined strategy based on peptide sequencing and Rapid Amplification of cDNA Ends (RACE). BmHYI has 410 amino acid residues containing the catalytic, positional and five potential N-glycosylation sites. The deduced protein sequence of BmHYI shares significant identity with venom hyaluronidases from bees and snakes. The phylogenetic analysis showed early divergence and independent evolution of BmHYI from other hyaluronidases. An extraordinarily high level of sequence similarity was detected among four sequences. But, BmHYII, BmHYIII and BmHYIV were short of stop-codon in the open reading frame and poly(A) signal in the 3' end.

Pelagia noctiluca (Scyphozoa) crude venom injection elicits oxidative stress and inflammatory response in rats

Cnidarian toxins represent a rich source of biologically active compounds. Since they may act via oxidative stress events, the aim of the present study was to verify whether crude venom, extracted from the jellyfish Pelagia noctiluca, elicits inflammation and oxidative stress processes, known to be mediated by Reactive Oxygen Species (ROS) production, in rats. In a first set of experiments, the animals were injected with crude venom (at three different doses 6, 30 and 60 µg/kg, suspended in saline solution, i.v.) to test the mortality and possible blood pressure changes. In a second set of experiments, to confirm that Pelagia noctiluca crude venom enhances ROS formation and may contribute to the pathophysiology of inflammation, crude venom-injected animals (30 µg/kg) were also treated with tempol, a powerful antioxidant (100 mg/kg i.p., 30 and 60 min after crude venom). Administration of tempol after crude venom challenge, caused a significant reduction of each parameter related to inflammation. The potential effect of Pelagia noctiluca crude venom in the systemic inflammation process has been here demonstrated, adding novel information about its biological activity.