Human Poisoning Research Articles

Molecular Characteristics and Pathogenicity of Staphylococcus aureus Exotoxins.

Staphylococcus aureus stands as one of the most pervasive pathogens given its morbidity and mortality worldwide due to its roles as an infectious agent that causes a wide variety of diseases ranging from moderately severe skin infections to fatal pneumonia and sepsis. S. aureus produces a variety of exotoxins that serve as important virulence factors in S. aureus-related infectious diseases and food poisoning in both humans and animals. For example, staphylococcal enterotoxins (SEs) produced by S. aureus induce staphylococcal foodborne poisoning; toxic shock syndrome toxin-1 (TSST-1), as a typical superantigen, induces toxic shock syndrome; hemolysins induce cell damage in erythrocytes and leukocytes; and exfoliative toxin induces staphylococcal skin scalded syndrome. Recently, Panton-Valentine leucocidin, a cytotoxin produced by community-associated methicillin-resistant S. aureus (CA-MRSA), has been reported, and new types of SEs and staphylococcal enterotoxin-like toxins (SEls) were discovered and reported successively. This review addresses the progress of and novel insights into the molecular structure, biological activities, and pathogenicity of both the classic and the newly identified exotoxins produced by S. aureus.

Tissue Distribution and Metabolization of Ciguatoxins in an Herbivorous Fish following Experimental Dietary Exposure to Gambierdiscus polynesiensis.

Ciguatoxins (CTXs), potent neurotoxins produced by dinoflagellates of the genera Gambierdiscus and Fukuyoa, accumulate in commonly consumed fish species, causing human ciguatera poisoning. Field collections of Pacific reef fish reveal that consumed CTXs undergo oxidative biotransformations, resulting in numerous, often toxified analogs. Following our study showing rapid CTX accumulation in flesh of an herbivorous fish, we used the same laboratory model to examine the tissue distribution and metabolization of Pacific CTXs following long-term dietary exposure. Naso brevirostris consumed cells of Gambierdiscus polynesiensis in a gel food matrix over 16 weeks at a constant dose rate of 0.36 ng CTX3C equiv g-1 fish d-1. CTX toxicity determination of fish tissues showed CTX activity in all tissues of exposed fish (eight tissues plus the carcass), with the highest concentrations in the spleen. Muscle tissue retained the largest proportion of CTXs, with 44% of the total tissue burden. Moreover, relative to our previous study, we found that larger fish with slower growth rates assimilated a higher proportion of ingested toxin in their flesh (13% vs. 2%). Analysis of muscle extracts revealed the presence of CTX3C and CTX3B as well as a biotransformed product showing the m/z transitions of 2,3-dihydroxyCTX3C. This is the first experimental evidence of oxidative transformation of an algal CTX in a model consumer and known vector of CTX into the fish food web. These findings that the flesh intended for human consumption carries the majority of the toxin load, and that growth rates can influence the relationship between exposure and accumulation, have significant implications in risk assessment and the development of regulatory measures aimed at ensuring seafood safety.

Microbiological Quality Test of Food at Market Restaurant in Gorontalo City Market

<div><table cellspacing="0" cellpadding="0" align="left"><tbody><tr><td align="left" valign="top"><p><em>Market food is very popular with the people of Indonesia because the price is very affordable, tastes good and has many variations. However, market food processing often ignores cleanliness starting from the processing process to the presentation so that it can cause food to be contaminated with Escherichia coli and Salmonella sp. bacteria. Food contaminated with bacteria if consumed can harm digestion so it can also cause diarrhea. The growth of these microbes can cause food to spoil making it unfit to eat and cause poisoning in humans and even death. This study aims to examine the quality of food from microbiological exposure. This research is an experimental study using the cup count method or the pour method to analyze the microbiological quality of food ingredients with 16 samples, namely Block 8 and Block 11 in the Central Market of Gorontalo City conducted from September to October 2020. Based on the test results with 3 repetitions at different times, it was obtained that samples that did not meet the requirements were in Block 8 RM 2 in the form of woku fish, and in Block 11 there were RM 1, namely chicken curry and RM 2, namely fried fish.</em></p><p><em> </em></p></td></tr></tbody></table></div><p><strong><em>Keyword: Bacteria, Escherichia coli, Food Market, Salmonella sp</em></strong></p>

Acute Effects of Brevetoxin-3 Administered via Oral Gavage to Mice.

Brevetoxins (BTXs) constitute a family of lipid-soluble toxic cyclic polyethers mainly produced by Karenia brevis, which is the main vector for a foodborne syndrome known as neurotoxic shellfish poisoning (NSP) in humans. To prevent health risks associated with the consumption of contaminated shellfish in France, the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) recommended assessing the effects of BTXs via an acute oral toxicity study in rodents. Here, we investigated the effect of a single oral administration in both male and female mice with several doses of BTX-3 (100 to 1,500 µg kg-1 bw) during a 48 h observation period in order to provide toxicity data to be used as a starting point for establishing an acute oral reference dose (ARfD). We monitored biological parameters and observed symptomatology, revealing different effects of this toxin depending on the sex. Females were more sensitive than males to the impact of BTX-3 at the lowest doses on weight loss. For both males and females, BTX-3 induced a rapid, transient and dose-dependent decrease in body temperature, and a transient dose-dependent reduced muscle activity. Males were more sensitive to BTX-3 than females with more frequent observations of failures in the grip test, convulsive jaw movements, and tremors. BTX-3's impacts on symptomatology were rapid, appearing during the 2 h after administration, and were transient, disappearing 24 h after administration. The highest dose of BTX-3 administered in this study, 1,500 µg kg-1 bw, was more toxic to males, leading to the euthanasia of three out of five males only 4 h after administration. BTX-3 had no effect on water intake, and affected neither the plasma chemistry parameters nor the organs' weight. We identified potential points of departure that could be used to establish an ARfD (decrease in body weight, body temperature, and muscle activity).

DON induced DNA damage triggers absence of p53-mediated G2 arrest and apoptosis in IPEC-1 cells

Deoxynivalenol (DON) stands among the prevalent mycotoxins, and usually contaminates cereal foods and animal feed, leading to human and animal clinical poisoning symptoms such as abdominal pain, diarrhea, and vomiting. To date, the mechanism of toxicity of DON in different mammalian cells is not fully elucidated. In this study, we explored the detrimental impacts of DON on porcine intestinal epithelial cells (IPEC-1), serving as a representative model for porcine intestinal epithelial cells. After treating cells with DON for 24 h, DON can significantly inhibit the activity of cells, induce the production of reactive oxygen species (ROS), significantly reduce the content of glutathione and the activity of catalase, and increase the activity of superoxide dismutase and malondialdehyde, leading to an imbalance in intracellular redox status. In addition, DON can induce DNA double-strand breaks, and decrease mitochondrial membrane potential. Furthermore, DON can promote the release of Cyt C through changes in mitochondrial permeability through inhibit the expression of B-cell lymphoma 2 (Bcl-2) proteins, leading to apoptosis through the mitochondrial pathway. On the other hand, we found that DON can cause IPEC-1 cells G2 phase cycle arrest. Different with our pervious study, DON induces cell cycle arrest in the G2 phase only by activating the ATM-Chk2-Cdc 25 C pathway, but cannot regulate the cell cycle arrest via the ATM-p53 pathway. These results indicate that DON can induce the same toxic phenotype in different cells, but its toxic mechanism is different. All these provide a rationale for revealing DON induced cytotoxicity and intestinal diseases.

Thallium(I) induces a prolonged inhibition of (6-4)photoproduct binding and UV damage excision repair activities in zebrafish (Danio rerio) embryos via protein inactivation

Cyclobutane pyrimidine dimer (CPD) and (6-4)photoproduct (6-4 PP) are two major types of UV-induced DNA lesion and 6-4 PP is more mutagenic than CPD. Activated by lesion detection, nucleotide excision repair (NER) eliminates CPDs and 6-4 PPs. Thallium (Tl) is a toxic metal existing primarily as Tl+ in the aquatic environment. Ingestion of Tl+-contaminated foods and water is a major route of human poisoning. As Tl+ may inhibit enzyme activities via binding to sulfhydryl groups, this study explored if Tl+ could intensify UV mutagenicity by inactivating NER-linked damage recognition factors using zebrafish (Danio rerio) embryo as a model system. Incubation of Tl+ (as thallium nitrate) at 0.1–0.4 μg/mL with zebrafish extracts for 20 min caused a concentration-dependent inhibition of 6-4 PP binding activities as shown by a photolesion-specific band shift assay, while CPD binding activities were insensitive to Tl+. The ability of Tl+ to suppress 6-4 PP detection was stronger than that of Hg2+. Exposure of zebrafish embryos at 1 h post fertilization (hpf) to Tl+ at 0.4–1 μg/mL for 9 or 71 h also specifically inhibited 6-4 PP detection, indicating that Tl+ induced a prolonged inhibition of 6-4 PP sensing ability primarily via its direct interaction with damage recognition molecules. Tl+-mediated inhibition of 6-4 PP binding in embryos at distinct stages resulted in a suppression of NER capacity monitored by a transcription-based DNA repair assay. Our results revealed the potential of Tl+ to enhance UV mutagenicity by disturbing the removal of 6-4 PP through repressing the lesion detection step of NER.

Types A and F Clostridium perfringens in healthcare wastewater from Ghana.

Clostridium perfringens causes gas gangrene and food poisoning in humans, and monitoring this bacterium is important for public health. Although whole-genome sequencing is useful to comprehensively understand the virulence, resistome, and global genetic relatedness of bacteria, limited genomic data from environmental sources and developing countries hamper our understanding of the richness of the intrinsic genomic diversity of this pathogen. Here, we successfully accumulated the genetic data on C. perfringens strains isolated from hospital effluent and provided the first evidence that predicted pathogenic C. perfringens may be disseminated in the clinical environment in Ghana. Our findings suggest the importance of risk assessment in the environment as well as the clinical setting to mitigate the potential outbreak of C. perfringens food poisoning in Ghana.

Revisiting Genetic Influence on Mercury Exposure and Intoxication in Humans: A Scoping Review.

Human intoxication to mercury is a worldwide health problem. In addition to the type and length of exposure, the genetic background plays an important role in mercury poisoning. However, reviews on the genetic influence in mercury toxicity are scarce and not systematic. Therefore, this review aimed to systematically overview the most recent evidence on the genetic influence (using single nucleotide polymorphisms, SNPs) on human mercury poisoning. Three different databases (PubMed/Medline, Web of Science and Scopus) were searched, and 380 studies were found that were published from 2015 to 2022. After applying inclusion/exclusion criteria, 29 studies were selected and data on characteristics (year, country, profile of participants) and results (mercury biomarkers and quantitation, SNPs, main findings) were extracted and analyzed. The largest number of studies was performed in Brazil, mainly involving traditional populations of the Tapajós River basin. Most studies evaluated the influence of the SNPs related to genes of the glutathione system (GST, GPx, etc.), the ATP-binding cassette transporters and the metallothionein proteins. The recent findings regarding other SNPs, such as those of apolipoprotein E and brain-derived neurotrophic factor genes, are also highlighted. The importance of the exposure level is discussed considering the possible biphasic behavior of the genetic modulation phenomena that could explain some SNP associations. Overall, recommendations are provided for future studies based on the analysis obtained in this scoping review.

Risk Assessment of Toxic Heavy Metals Concentration of Fish and Drinking Water in Nsukka Metropolis, South East, Nigeria

Background: Toxic Heavy Metals (THMs) threaten food safety and result in human poisonings. It seems to be few studies on THMs contamination in food chain in developing countries. Current investigation determine the concentration and health risk of arsenic (As), cadmium (Cd), lead (Pb), as well as mercury (Hg) in fish and water at Nsukka, Metropolis, Enugu state, Nigeria.
 Methods: Forty eight samples; 24 (catfish and tilapia) fish and 24 (borehole, sachet, and bottled) water were randomly collected from two major markets and districts in Nsukka Metropolis and were evaluated for THMs using Atomic Absorption Spectrophotometer. The Estimated Daily Intake, Target Hazard Quotient, Hazard Index, and Cancer Risk (CR) were assessed as well.
 Results: THMs analaysis showed that As, Cd, and Hg were at 100% and Pb being at 16% in all the fish samples while 12.5% of fish of exceeded the Hg Maximum Permissible Limit (MPL) of 0.050 mg/kg, that not statistically significant (p>0.05).On the other hand, based on the analysis of all water samples, Hg and As were detected at 100% rate, Cd at 58.3% while Pb was not identified. The values above the MPL appeared to be 9 (37.5%), 2 (8.3%), and 3(12.5%) for Hg, As, and Cd, respectively in water while not statistically significant (p>0.05). The mean value of Hg (0.06425 mg/kg) in roasted fish as well as Cd (0.0065 and 0.0105) mg/ml in tap and bottled water respectively surpassed the MPL although not statistically significant (p>0.05). The Estimated Daily Intake of THMs except Cd in fish were proved to be within the Provisional Tolerable Daily Intake in contrast with As and Cd in water. CR is present both in children and adults with CR value >1.
 Conclusion: The finding of THMs in fish and water above the MPL is regarded as potential health risk for the consumers of such contaminated water and fish in the investigation scope.

The Role of Trace Elements in Cardiovascular Diseases.

Essential trace elements play an important role in human physiology and are associated with various functions regulating cellular metabolism. Non-essential trace elements, on the other hand, often have well-documented toxicities that are dangerous for the initiation and development of diseases due to their widespread occurrence in the environment and their accumulation in living organisms. Non-essential trace elements are therefore regarded as serious environmental hazards that are harmful to health even in low concentrations. Many representatives of these elements are present as pollutants in our environment, and many people may be exposed to significant amounts of these substances over the course of their lives. Among the most common non-essential trace elements are heavy metals, which are also associated with acute poisoning in humans. When these elements accumulate in the body over years of chronic exposure, they often cause severe health damage in a variety of tissues and organs. In this review article, the role of selected essential and non-essential trace elements and their role in the development of exemplary pathophysiological processes in the cardiovascular system will be examined in more detail.

Pathology of human organic mercury poisoning: Lessons from an autopsy case

We had an opportunity to perform a general autopsy of a case with chronic organic mercury toxicosis in 2017. He had been engaged in synthesizing a variety of organic mercury compounds throughout the four years from 1966 and developed chronic organic mercury poisoning in 1969. Almost forty years on, he still remained to complain of persistent paresthesia at finger tips and tongue, and of narrowed visual field. Neurological examinations clarified a rise of two-point discrimination thresholds, a systemic increase of touch thresholds, constriction of the visual field caused by general visual depression, and sensorineural hearing loss while primary modalities of his somatic, visual, and auditory sensations were preserved. These symptoms and signs are characteristic of human organic mercury poisoning. Furthermore, he had difficulty in processing a lot of visual and auditory information at a time. His two-point discrimination thresholds and systemic elevation of touch thresholds were comparable to those of mild organic mercury poisoning cases. He had slight sensory ataxia, but not cerebellar ataxia. Brain [18F]-2-fluorodeoxyglucose positron emission tomography analysis exhibited marked hypometabolism at bilateral postcentral gyrus, striate cortex, and superior temporal gyrus, but not the cerebellum. Histopathological studies revealed considerable decrease of granular neurons and neuronal networks in bilateral primary somatosensory, visual, and auditory cortices. Those characteristic brain lesions fairly explain increase of thresholds of somatic, visual, and auditory sensations, and degradation of integrating sensory information. It is noted that damages to the peripheral nervous system and the cerebellum were not detected and that his intellectual faculties were preserved.

Diversity and distribution of species of the planktonic dinoflagellate genus Alexandrium (Dinophyta) from the tropical and subtropical Mexican Pacific Ocean

Abstract Species of the dinoflagellate genus Alexandrium are marine and planktonic forms, widely distributed, and some are recognized to form harmful algal blooms and to produce saxitoxins causing Paralytic Shellfish Poisoning in humans, and other toxins. We studied the species composition of Alexandrium in tropical and subtropical coastal areas of the Mexican Pacific: from the southern Gulf of California to the Gulf of Tehuantepec. Eleven Alexandrium species were identified, described, and illustrated using light microscopy, and occasionally scanning electron microscopy for certain species. Additionally, the genetic characterization of seven strains and four species, was performed, using sequences of the D1/D2 LSU rDNA and ITS regions. We identified the species (morphospecies): Alexandrium affine, A. gaarderae, A. globosum, A. leei, A. margalefii, A. minutum, A. monilatum, A. pseudogonyaulax, A. tamarense, A. tamiyavanichii, and A. tropicale. Of these, A. affine, A. leei, A. minutum, A. monilatum, A. pseudogonyaulax, A. tamarense and A. tamiyavanichii have been widely recognized as harmful algae. Alexandrium gaarderae, A. globosum and A. tropicale are new records for the Mexican Pacific. This is the first morphological documentation of A. pseudogonyaulax. Future studies of the genus might increase its species richness if more cultures are established and metabarcoding approach is used.

Effects of Biosorption Technique Using Various Fruit Waste Activated Carbon in Improving Chenderiang River Water Quality

The release of heavy metals from industries and other human-made activities into waterways is the primary cause of environmental pollution. Heavy metals are very toxic and once ingested through the mouth and nose; they can accumulate in the organs inside the human body and poison the internal organs with serious illnesses and even can cause death. Hence, in order to determine the water quality, biosorption technique using low-cost, eco-friendly fruit or agricultural wastes i.e., banana and orange peel activated carbon were prepared and characterized using FT-IR spectroscopy and nitrogen adsorption-desorption analysis. The adsorbents were then used to treat and identify the physicochemical parameters of Chenderiang River water, Tapah, Perak, Malaysia. Physicochemical analysis of river water sample such as DO, BOD5, pH, Temperature, EC, Turbidity, Hardness, Alkalinity, TSS, (PO4)3−, AN, Cu, Cr, Fe, and Zn before and after treatment were measured using Multiprobe system, EC meter, Lamotte Smart3® Colorimeter, and AAS. The results showed that orange peel (OP) activated carbon is more effective than banana peel (BP) activated carbon in reducing most of the pollutants including heavy metals in Chenderiang river water. The findings of this study showed that the biosorption technique using fruit waste is a low-cost, biodegradable and eco-friendly alternative method to remove pollutants including heavy metals in water and indirectly can reduce municipal solid waste. Therefore, can reduce water pollution and ensure good water quality.

A 15-Year Retrospective Review of Ciguatera in the Madeira Islands (North-East Atlantic, Portugal).

The first ciguatera fish poisoning (CFP) in Portugal dates from 2008 when 11 people reported CFP symptoms after consuming a 30 kg amberjack caught around the Selvagens Islands (Madeira Archipelago). Since then, 49 human poisonings have been reported. The emergence of a new threat challenged scientists and regulators, as methods for toxic microalgae analyses and ciguatoxin (CTX) detection were not implemented. To minimise the risk of ciguatera, the Madeira Archipelago authorities interdicted fisheries in Selvagens Islands and banned the capture of amberjacks weighing more than 10 kg in the entire region of Madeira Archipelago. The accurate identification and quantification of the benthic toxin-producing algae species spreading to new areas require efforts in terms of both microscopy and molecular techniques. Two ciguatera-causing dinoflagellates, Gambierdiscus excentricus and Gambierdiscus australes, were identified in the Madeira Island and Selvagens sub-archipelago, respectively. Regarding the CTX analysis (N2a cell-based assay and LC-MS) in fish, the results indicate that the Selvagens Islands are a ciguatera risk area and that fish vectoring CTX are not limited to top predator species. Nevertheless, advances and improvements in screening methods for the fast detection of toxicity in seafood along with certified reference material and sensitive and selective targeted analytical methods for the determination of CTX content are still pending. This study aims to revise the occurrence of ciguatera cases in the Madeira Archipelago since its first detection in 2008, to discuss the risk management strategy that was implemented, and to provide a summary of the available data on the bioaccumulation of CTX in marine fish throughout the marine food web, taking into consideration their ecological significance, ecosystem dynamics, and fisheries relevance.

Beta-Caryophyllene, a Plant-Derived CB2 Receptor Agonist, Protects SH-SY5Y Cells from Cadmium-Induced Toxicity.

Cadmium (Cd) is a transition heavy metal that is able to accumulate in the central nervous system and may induce cell death through reactive oxygen species (ROS)-mediated mechanisms and inactivating the antioxidant processes, becoming an important risk factor for neurodegenerative diseases. The antioxidant effects of cannabinoid receptor modulation have been extensively described, and, in particular, β-Caryophyllene (BCP), a plant-derived cannabinoid 2 receptor (CB2R) agonist, not only showed significant antioxidant properties but also anti-inflammatory, analgesic, and neuroprotective effects. Therefore, the aim of the present study was to evaluate BCP effects in a model of Cd-induced toxicity in the neuroblastoma SH-SY5Y cell line used to reproduce Cd intoxication in humans. SH-SY5Y cells were pre-treated with BCP (25, 50, and 100 μM) for 24 h. The day after, cells were challenged with cadmium chloride (CdCl2; 10 μM) for 24 h to induce neuronal toxicity. CdCl2 increased ROS accumulation, and BCP treatment significantly reduced ROS production at concentrations of 50 and 100 μM. In addition, CdCl2 significantly decreased the protein level of nuclear factor erythroid 2-related factor 2 (Nrf2) compared to unstimulated cells; the treatment with BCP at a concentration of 50 μM markedly increased Nrf2 expression, thus confirming the BCP anti-oxidant effect. Moreover, BCP treatment preserved cells from death, regulated the apoptosis pathway, and showed a significant anti-inflammatory effect, thus reducing the pro-inflammatory cytokines increased by the CdCl2 challenge. The results indicated that BCP preserved neuronal damage induced by Cd and might represent a future candidate for protection in neurotoxic conditions.

Effect of Jackfruit Leaf Extract (Artocarpus heterophyllus) on Sitophilus oryzae Mortality and Rice Quality.

Sitophilus oryzae is an insect pest known for its destructive impact on rice crops. Chemical pesticides continue to be employed for the prevention of Sitophilus oryzae. The aforementioned phenomenon exerts adverse effects, notably in the form of human intoxication. Hence, one alternate approach to address the issue involves utilizing a preparation derived from the leaves of the jackfruit tree. The leaves of the jackfruit tree are known to possess many bioactive compounds such as flavonoids, saponins, and tannins, which have insecticidal properties. Hence, the objectives of this study are to investigate the impact of jackfruit leaf extract on the mortality rate of rice insects and to evaluate the quality of rice. The study was carried out in the Biology Laboratory of the Faculty of Education and Teacher Training at the Tadulako University. The study employed a research strategy known as a completely randomized design (CRD), which included five treatments. Each treatment was repeated in four biological and ten technical replicates. The treatments were as follows: treatment A served as the control and involved the use of Bestrin forte, treatment B involved the application of a 10% jackfruit leaf extract, treatment C involved the application of a 20% jackfruit leaf extract, treatment D involved the application of a 30% jackfruit leaf extract, and treatment E involved the application of a 40% jackfruit leaf extract. Every treatment was administered through spraying to all ten insects and that was repeated four times. The data collected were subjected to analysis using analysis of variance (ANOVA) and supported by the SPSS-25 software. The findings of the study indicated that the application of jackfruit leaf extract (Artocarpus heterophyllus) at specific time intervals (20th, 40th, and 60th minutes) resulted in a noteworthy impact on the death rate of rice beetles. Furthermore, the extracts successfully preserved the olfactory attributes of the rice, ensuring its quality. Nevertheless, their ability to uphold the standard of the rice in relation to its color and flavor was inadequate. The efficacy of the jackfruit leaf extract in eradicating rice bugs was found to be highest when applied at a concentration of 40%.

Antibody-free and selective detection of okadaic acid using an affinity peptide-based indirect assay.

Okadaic acid (OA) is a type of marine biotoxin produced by some species of dinoflagellates in marine environments. Consumption of shellfish contaminated with OA can cause diarrhetic shellfish poisoning (DSP) in humans with symptoms that typically include abdominal pain, diarrhea and vomiting. In this study, we developed an affinity peptide-based direct competition enzyme-linked immunosorbent assay (dc-ELISA) for the detection of OA in real samples. The OA-specific peptide was successfully identified via M13 biopanning and a series of peptides were chemically synthesized and characterized their recognition activities. The dc-ELISA system showed good sensitivity and selectivity with a half-maximal inhibitory concentration (IC50) of 148.7ng/mL and a limit of detection (LOD) of 5.41ng/mL (equivalent, 21.52ng/g). Moreover, the effectiveness of the developed dc-ELISA was validated using OA-spiked shellfish samples, and the developed dc-ELISA showed a high recovery rate. These results suggest that the affinity peptide-based dc-ELISA can be a promising tool for detecting OA in shellfish samples.

Design and characterization of a multi-epitope vaccine against Clostridium botulinum A3 Loch Maree intoxication in humans

Clostridium botulinum Loch Maree expresses an extremely potent botulinum neurotoxin subtype, A3 causing botulism and several gastrointestinal disorders in mammals. Several recombinant vaccines have been developed for human botulism and no vaccine is currently available for the treatment of diseases caused by other virulence factors. Hence, we designed, constructed, and characterized a multi-epitope vaccine from new virulence proteins identified from this organism using an immunoinformatics approach. The vaccine construct used in this study was designed from 6B cell linear epitopes, 12 cytotoxic T cell lymphocyte epitopes, and 15 helper T cell lymphocyte epitopes, with a defensin adjuvant and adjusting linker sequences. A molecular modeling approach was used to model, refine, and validate the 3D structure of the vaccine construct. Molecular docking studies were performed to determine the stability of the molecular interactions between the vaccine construct and human toll-like receptor 7. The in silico molecular cloning was used to clone a codon-optimized synthetic vaccine gene in pCYB1 vector and expressed in Escherichia coli. The results of this study identified six new virulence proteins: peptidoglycan hydrolase, SCP-like extracellular protein, N-acetylmuramoyl-l-alanine amidase, putative membrane protein, drug/metabolite exporter, and bacillolysin. The top B-cell, cytotoxic T-cell lymphocyte, and helper T-lymphocyte epitopes were predicted from these virulence proteins with greater accuracy and reliability. HLA-A*02:01 and HLA-A*03:01 were identified as HLA-A-binding alleles for cytotoxic T-cell lymphocyte epitopes. DRB1*0110 and DRB1*0115 are the dominant alleles that bind to helper T-cell lymphocyte epitopes. The synthetic gene construct was highly expressed in a heterologous host and produced considerable amounts of antigenic protein. The multi-epitope vaccine is more conservative in the sequence-structure–function link, immunogenic with less allergenicity, and possibly provokes cellular and humoral immunity. The present study suggests that the designed multi-epitope vaccine is a promising prophylactic candidate for the virulence and intoxication caused by subtype A3 strains.

Poison ivy (Toxicodendron radicans) leaf shape variability: Why plant avoidance‐by‐identification recommendations likely do not substantially reduce poison ivy rash incidence

Societal Impact StatementAvoidance of poison ivy plants is currently the primary approach to prevent the estimated 30–50 million annual poison ivy skin rash cases. The “leaves of three let it be” mnemonic device lacks specificity to differentiate poison ivy from other three‐leaflet native plants. This report demonstrated that poison ivy leaves show marked total leaf shape variability that likely confounds accurate poison ivy plant identification, and significantly undermines a poison ivy avoidance strategy for mitigating poison ivy rash cases. Therefore, there is an ongoing need to develop prophylactic medical procedures to prevent poison ivy rash that do not depend on human poison ivy plant identification.Summary Urushiol is the natural product produced by poison ivy (Toxicodendron radicans) that is responsible for millions of cases of delayed contact allergenic dermatitis in North America each year. Avoidance of poison ivy plant material is the clinically recommended strategy for preventing urushiol‐induced dermatitis symptoms. However, poison ivy leaf shape is anecdotally notoriously variable, thereby confounding accurate poison ivy identification. This study focused on quantitative analyses of poison ivy and a common poison ivy look‐alike (American hog peanut) leaf shape variability in North America to empirically validate the high degree of poison ivy leaf shape plasticity. Poison ivy and American hog peanut iNaturalist.org records were scored for seven attributes of compound leaf shape that were combined to produce a total leaf complexity score. Both the mean and the distribution of poison ivy total leaf complexity scores were significantly greater than that of American hog peanut. Non‐metric multidimensional scaling analyses corroborated a high degree of poison ivy leaf shape variability relative to American hog peanut. A poison ivy accession producing frequent palmate penta‐leaflet compound leaves was evaluated using linear regression modeling. Poison ivy total leaf complexity was exceedingly variable across a given latitude or longitude. With that said, there was a small but significant trend of poison ivy total leaf complexity increasing from east to west. Palmate penta‐leaflet formation was significantly correlated with a stochastic leaflet deep‐lobing developmental process in one unusual poison ivy accession. The empirically‐validated poison ivy leaf shape hypervariability described in this report likely confounds accurate poison ivy identification, thereby likely resulting in many accidental urushiol‐induced clinical allergenic dermatitis cases each year.

Okadaic Acid Is at Least as Toxic as Dinophysistoxin-1 after Repeated Administration to Mice by Gavage.

Okadaic acid (OA) and its analogues cause diarrhetic shellfish poisoning (DSP) in humans, and risk assessments of these toxins require toxicity equivalency factors (TEFs), which represent the relative toxicities of analogues. However, no human death by DSP toxin has been reported, and its current TEF value is based on acute lethality. To properly reflect the symptoms of DSP, such as diarrhea without death, the chronic toxicity of DSP toxins at sublethal doses should be considered. In this study, we obtained acute oral LD50 values for OA and dinophysistoxin-1 (DTX-1) (1069 and 897 μg/kg, respectively) to set sublethal doses. Mice were treated with sublethal doses of OA and DTX-1 for 7 days. The mice lost body weight, and the disease activity index and intestinal crypt depths increased. Furthermore, these changes were more severe in OA-treated mice than in the DTX-1-treated mice. Strikingly, ascites was observed, and its severity was greater in mice treated with OA. Our findings suggest that OA is at least as toxic as DTX-1 after repeated oral administration at a low dose. This is the first study to compare repeated oral dosing of DSP toxins. Further sub-chronic and chronic studies are warranted to determine appropriate TEF values for DSP toxins.