Unveiling the link between Raphidiopsis raciborskii blooms and saxitoxin levels: Evaluating water quality in tropical reservoirs, Brazil

The proliferation of Raphidiopsis raciborskii blooms has sparked concerns regarding potential human exposure to heightened saxitoxins (STXs) levels. Thus, comprehending how environmental elements drive the proliferation of this STXs-producing species can aid in predicting human exposure risks. This study aimed to explore the link between cyanobacteria R. raciborskii, STXs cyanotoxins, and environmental factors in 37 public supply reservoirs in the tropical region and assess potential health hazards these toxins pose in the reservoir waters. A Structural Equation Model was used to assess the impact of environmental factors (water volume and physical and chemical variables) on R. raciborskii biomass and STXs levels. Furthermore, the potential risk of STXs exposure from consuming untreated reservoir water was evaluated. Lastly, the cumulative distribution function (CDF) of STXs across the reservoirs was computed. Our findings revealed a correlation between R. raciborskii biomass and STXs concentrations. Total phosphorus emerged as a critical environmental factor positively influencing species biomass and indirectly affecting STXs levels. pH significantly influenced STXs concentrations, indicating different factors influencing R. raciborskii biomass and STXs. Significantly, for the first time, the risk of STXs exposure was gauged using the risk quotient (HQ) for untreated water consumption from public supply reservoirs in Brazil's semi-arid region. Although the exposure risks were generally low to moderate, the CDF underscored the risk of chronic exposure due to low toxin concentrations in over 90% of samples. These outcomes emphasize the potential expansion of R. raciborskii in tropical settings due to increased phosphorus, amplifying waterborne STXs levels and associated intoxication risks. Thus, this study reinforces the importance of nutrient control, particularly phosphorus regulation, as a mitigation strategy against R. raciborskii blooms and reducing STXs intoxication hazards.

Exploring Caenorhabditis elegans as Parkinson's Disease Model: Neurotoxins and Genetic Implications

Parkinson's disease (PD) is the second most common neurodegenerative disease in the world, the first being Alzheimer's disease. Patients with PD have a loss of dopaminergic neurons in the substantia nigra of the basal ganglia, which controls voluntary movements, causing a motor impairment as a result of dopaminergic signaling impairment. Studies have shown that mutations in several genes, such as SNCA, PARK2, PINK1, DJ-1, ATP13A2, and LRRK2, and the exposure to neurotoxic agents can potentially increase the chances of PD development. The nematode Caenorhabditis elegans (C. elegans) plays an important role in studying the risk factors, such as genetic factors, aging, exposure to chemicals, disease progression, and drug treatments for PD. C. elegans has a conserved neurotransmission system during evolution; it produces dopamine, through the eight dopaminergic neurons; it can be used to study the effect of neurotoxins and also has strains that express human α-synuclein. Furthermore, the human PD-related genes, LRK-1, PINK-1, PDR-1, DJR-1.1, and CATP-6, are present and functional in this model. Therefore, this review focuses on highlighting and discussing the use of C. elegans an in vivo model in PD-related studies. Here, we identified that nematodes exposed to the neurotoxins, such as 6-OHDA, MPTP, paraquat, and rotenone, had a progressive loss of dopaminergic neurons, dopamine deficits, and decreased survival rate. Several studies have reported that expression of human LRRK2 (G2019S) caused neurodegeneration and pink-1, pdr-1, and djr-1.1 deletion caused several effects PD-related in C. elegans, including mitochondrial dysfunctions. Of note, the deletion of catp-6 in nematodes caused behavioral dysfunction, mitochondrial damage, and reduced survival. In addition, nematodes expressing α-synuclein had neurodegeneration and dopamine-dependent deficits. Therefore, C. elegans can be considered an accurate animal model of PD that can be used to elucidate to assess the underlying mechanisms implicated in PD to find novel therapeutic targets.

Effect of exercise on sleep quality in Parkinson's disease: a mini review

The growing incidence of Parkinson's Disease (PD) is a major burden on the healthcare system. PD is caused by the degeneration of dopaminergic neurons and is known for its effects on motor function and sleep. Sleep is vital for maintaining proper homeostasis and clearing the brain of metabolic waste. Adequate time spent in each sleep stage can help maintain homeostatic function; however, patients with PD appear to exhibit sleep impairments. Although medications enhance the function of remaining dopaminergic neurons and reduce motor symptoms, their potential to improve sleep is still under question. Recently, research has shifted towards exercise protocols to help improve sleep in patients with PD. This review aims to provide an overview of how sleep is impaired in patients with PD, such as experiencing a reduction in time spent in slow-wave sleep, and how exercise can help restore normal sleep function. A PubMed search summarized the relevant research on the effects of aerobic and resistance exercise on sleep in patients with PD. Both high and low-intensity aerobic and resistance exercises, along with exercises related to balance and coordination, have been shown to improve some aspects of sleep. Neurochemically, sleeping leads to an increase in toxin clearance, including α-synuclein. Furthermore, exercise appears to enhance the concentration of brain-derived neurotrophic factors, which has preliminary evidence to suggest correlations to time spent in slow-wave sleep. More research is needed to further elucidate the physiological mechanism pertaining to sleep and exercise in patients with PD.

A review on aquatic toxins - Do we really know it all regarding the environmental risk posed by phytoplankton neurotoxins?

Aquatic toxins are potent natural toxins produced by certain cyanobacteria and marine algae species during harmful cyanobacterial and algal blooms (CyanoHABs and HABs, respectively). These harmful bloom events and the toxins produced during these events are a human and environmental health concern worldwide, with occurrence, frequency and severity of CyanoHABs and HABs being predicted to keep increasing due to ongoing climate change scenarios. These contexts, as well as human health consequences of some toxins produced during bloom events have been thoroughly reviewed before. Conversely, the wider picture that includes the non-human biota in the assessment of noxious effects of toxins is much less covered in the literature and barely covered by review works. Despite direct human exposure to aquatic toxins and related deleterious effects being responsible for the majority of the public attention to the blooms' problematic, it constitutes a very limited fraction of the real environmental risk posed by these toxins. The disruption of ecological and trophic interactions caused by these toxins in the aquatic biota building on deleterious effects they may induce in different species is paramount as a modulator of the overall magnitude of the environmental risk potentially involved, thus necessarily constraining the quality and efficiency of the management strategies that should be placed. In this way, this review aims at updating and consolidating current knowledge regarding the adverse effects of aquatic toxins, attempting to going beyond their main toxicity pathways in human and related models' health, i.e., also focusing on ecologically relevant model organisms. For conciseness and considering the severity in terms of documented human health risks as a reference, we restricted the detailed revision work to neurotoxic cyanotoxins and marine toxins. This comprehensive revision of the systemic effects of aquatic neurotoxins provides a broad overview of the exposure and the hazard that these compounds pose to human and environmental health. Regulatory approaches they are given worldwide, as well as (eco)toxicity data available were hence thoroughly reviewed. Critical research gaps were identified particularly regarding (i) the toxic effects other than those typical of the recognized disease/disorder each toxin causes following acute exposure in humans and also in other biota; and (ii) alternative detection tools capable of being early-warning signals for aquatic toxins occurrence and therefore provide better human and environmental safety insurance. Future directions on aquatic toxins research are discussed in face of the existent knowledge, with particular emphasis on the much-needed development and implementation of effective alternative (eco)toxicological biomarkers for these toxins. The wide-spanning approach followed herein will hopefully stimulate future research more broadly addressing the environmental hazardous potential of aquatic toxins.

Neuromodulators for Skin

Neurotoxins are the most popular nonsurgical aesthetic procedure for men and women of all ages. Five botulinum toxin A (BoNTA) products represent the current palette of available BoNTA for cosmetic use. Off-label uses of BoNTA continue to expand and are now used for skin rejuvenation, to treat various skin disorders, and in facial nerve paralysis. Dermal and subdermal injections of dilute BoNTA has grown in popularity and been shown to improve skin texture and quality. Common targets for chemodenervation in facial nerve synkinesis are ipsilateral orbicularis oculi, mentalis, depressor anguli oris, buccinator, corrugator muscles, and the ipsilateral and/or contralateral frontalis.

Transcriptomic and proteomic analyses reveal the first occurrence of diverse toxin groups in Millepora alcicornis

Millepora alcicornis is a reef-forming cnidarian widely distributed in the Mexican Caribbean. Millepora species or "fire corals" inflict a painful stinging reaction in humans when touched. Even though hundreds of organic and polypeptide toxins have been characterized from sea anemones and jellyfish, there are few reports regarding the diversity of toxins synthesized by fire corals. Here, based on transcriptomic analysis of M. alcicornis, several predicted proteins that show amino acid sequence similarity to toxins were identified, including neurotoxins, metalloproteases, hemostasis-impairing toxins, serin proteases, cysteine-rich venom proteins, phospholipases, complement system-impairing toxins, phosphodiesterases, pore-forming toxins, and L-aminoacid oxidases. The soluble nematocyst proteome of this organism was shown to induce hemolytic, proteolytic, and phospholipase A2 effects by gel zymography. Protein bands or spots on 1D- and 2D-PAGE gels corresponding to zones of hemolytic and enzymatic activities were excised, subjected to in-gel digestion with trypsin, and analyzed by mass spectrometry. These proteins exhibited sequence homology to PLA2s, metalloproteinases, pore-forming toxins, and neurotoxins, such as actitoxins and CrTX-A. The complex array of venom-related transcripts that were identified in M. alcicornis, some of which are first reported in "fire corals", provide novel insight into the structural richness of Cnidarian toxins and their distribution among species. SIGNIFICANCE: Marine organisms are a promising source of bioactive compounds with valuable contributions in diverse fields such as human health, pharmaceuticals, and industrial application. Currently, not much attention has been paid to the study of fire corals, which possess a variety of molecules that exhibit diverse toxic effects and therefore have great pharmaceutical and biotechnological potential. The isolation and identification of novel marine-derived toxins by classical approaches are time-consuming and have low yields. Thus, next-generation strategies, like base-'omics technologies, are essential for the high-throughput characterization of venom compounds such as those synthesized by fire corals. This study moves the field forward because it provides new insights regarding the first occurrence of diverse toxin groups in Millepora alcicornis. The findings presented here will contribute to the current understanding of the mechanisms of action of Millepora toxins. This research also reveals important information related to the potential role of toxins in the defense and capture of prey mechanisms and for designing appropriate treatments for fire coral envenomation. Moreover, due to the lack of information on the taxonomic identification of Millepora, the insights presented here can advise the taxonomic classification of the species of this genus.

Three finger toxins of elapids: structure, function, clinical applications and its inhibitors

The WHO lists snakebite as a "neglected tropical disease". In tropical and subtropical areas, envenoming is an important public health issue. This review article describes the structure, function, chemical composition, natural inhibitors, and clinical applications of Elapids' Three Finger Toxins (3FTX) using scientific research data. The primary venomous substance belonging to Elapidae is 3FTX, that targets nAChR. Three parallel β-sheets combine to create 3FTX, which has four or five disulfide bonds. The three primary types of 3FTX are short-chain, long-chain, and nonconventional 3FTX. The functions of 3FTX depend on the specific toxin subtype and the target receptor or ion channel. The well-known effect of 3FTX is probably neurotoxicity because of the severe consequences of muscular paralysis and respiratory failure in snakebite victims. 3FTX have also been studied for their potential clinical applications. α-bungarotoxin has been used as a molecular probe to study the structure and function of nAChRs (Nicotinic Acetylcholine Receptors). Acid-sensing ion channel (ASIC) isoforms 1a and 1b are inhibited by Mambalgins, derived from Black mamba venom, which hinders their function and provide an analgesic effect. α- Cobra toxin is a neurotoxin purified from Chinese cobra (Naja atra) binds to nAChR at the neuronal junction and causes an analgesic effect for moderate to severe pain. Some of the plants and their compounds have been shown to inhibit the activity of 3FTX, and their mechanisms of action are discussed.

Evaluating the effect of alpha-mangostin on neural toxicity induced by acrylamide in rats

Acrylamide (ACR) is known to be a neurotoxic agent for humans and animals that has many applications in industry. Alpha-mangostin is a natural antioxidant that is extracted from mangosteen. This study aimed to investigate the protective effects of alpha-mangostin against ACR-induced neurotoxicity in rats and PC12 cells. Male Wistar rats were used in this investigation for 11 days, divided into 8 groups: 1. control group (normal saline), 2. ACR (50 mg/kg, i.p.), 3-6. ACR + alpha-mangostin (20, 40, 60 mg/kg, p.o.), 7. ACR + vitamin E (200 mg/kg, i.p., every other day) 8. alpha-mangostin (60 mg/kg, p.o.). On the last day of the study, the behavioral test was performed. The amounts of malondialdehyde (MDA) and glutathione (GSH) were measured. Also, the effects of ACR and alpha-mangostin were assessed by MTT assay on PC12 cells, and the levels of reactive oxygen species (ROS), B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), and cleaved caspase-3 proteins were measured by Western blotting. Receiving ACR caused motor disorders in animals, increased MDA, and decreased GSH levels of the cerebral cortex versus the control group. Alpha-mangostin (60 mg/kg) reduced ACR motility disorders, MDA amounts, and augmented GSH levels. The concurrent administration of vitamin E and ACR reduced gait score, MDA level, and amplified GSH content versus the ACR group. In the in vitro section, alpha-mangostin (1.25 µM, 24 h) increased cell viability, attenuated ROS, Bax/Bcl-2, and cleaved caspase-3 levels versus the ACR group. Alpha-mangostin reduced the toxicity of ACR by inhibiting oxidative stress and apoptosis. Therefore, it could be a promising compound for managing ACR-induced neurotoxicity.

Investigating the effect of telmisartan on acrylamide-induced neurotoxicity through in vitro and in vivo methods

Objectives

Acrylamide (ACR) is an environmental contaminant and neurotoxin. Telmisartan is an AT1 blocker that has neuroprotective properties basically through its anti-oxidant effect. The effect of telmisartan on ACR-induced neurotoxicity was investigated in this study.

Materials and Methods

Male Wistar rats were randomly assigned to eight groups (n=6): 1:Control (normal saline), 2:ACR (50 mg/kg, 11 days, IP), 3:ACR+vitamin E (200 mg/kg, every other day, 11 days), 4-6:ACR+telmisartan (0.6, 1.25, and 2.5 mg/kg, 11 days, IP), 7:ACR+telmisartan (0.6 mg/kg, days 3-11), 8:Telmisartan (2.5 mg/kg, 11 days). The behavioral test and blood pressure were assessed after 11 days. Then, the levels of MDA and GSH in brain tissue were measured. The MTT assay was used to evaluate the effect of telmisartan on ACR-induced cytotoxicity.

Results

Exposing PC12 cells to ACR decreased cell viability versus the control group. Pretreating PC12 cells with telmisartan (0.0125, 0.025 µM) enhanced cell viability compared with the ACR group. Compared with control samples, ACR significantly caused motor impairment, elevated MDA, and reduced GSH levels. Locomotor abnormalities were significantly ameliorated by telmisartan (0.6, 1.25 mg/kg, 11 days) and vitamin E versus the ACR group. Receiving telmisartan (0.6, 1.25, and 2.5 mg/kg) and vitamin E along with ACR decreased MDA levels and enhanced GSH content compared with the ACR group. There was no significant difference in animal blood pressure between the groups.

Conclusion

Oxidative stress has a chief role in the neurotoxicity of ACR. Telmisartan (in doses that do not affect blood pressure) ameliorated ACR-induced toxicity by inhibiting oxidative stress.

Potential neurotoxic activity of diverse molecules released by astrocytes

Astrocytes are the main support cells of the central nervous system. They also participate in neuroimmune reactions. In response to pathological and immune stimuli, astrocytes transform to reactive states characterized by increased release of inflammatory mediators. Some of these molecules are neuroprotective and inflammation resolving while others, including reactive oxygen species (ROS), nitric oxide (NO), matrix metalloproteinase (MMP)- 9, L-glutamate, and tumor necrosis factor α (TNF), are well-established toxins known to cause damage to surrounding cells and tissues. We hypothesized that similar to microglia, the brain immune cells, reactive astrocytes can release a broader set of diverse molecules that are potentially neurotoxic. A literature search was conducted to identify such molecules using the following two criteria: 1) evidence of their expression and secretion by astrocytes and 2) direct neurotoxic action. This review describes 14 structurally diverse molecules as less-established astrocyte neurotoxins, including C-X-C motif chemokine ligand (CXCL)10, CXCL12/CXCL12(5-67), FS-7-associated surface antigen ligand (FasL), macrophage inflammatory protein (MIP)- 2α, TNF-related apoptosis inducing ligand (TRAIL), pro-nerve growth factor (proNGF), pro-brain-derived neurotrophic factor (proBDNF), chondroitin sulfate proteoglycans (CSPGs), cathepsin (Cat)B, group IIA secretory phospholipase A₂ (sPLA₂-IIA), amyloid beta peptides (Aβ), high mobility group box (HMGB)1, ceramides, and lipocalin (LCN)2. For some of these molecules, further studies are required to establish either their direct neurotoxic effects or the full spectrum of stimuli that induce their release by astrocytes. Only limited studies with human-derived astrocytes and neurons are available for most of these potential neurotoxins, which is a knowledge gap that should be addressed in the future. We also summarize available evidence of the role these molecules play in select neuropathologies where reactive astrocytes are a key feature. A comprehensive understanding of the full spectrum of neurotoxins released by reactive astrocytes is key to understanding neuroinflammatory diseases characterized by the adverse activation of these cells and may guide the development of novel treatment strategies.

Cytochrome P450 enzymes and metabolism of drugs and neurotoxins within the mammalian brain

Cytochrome P450 enzymes (CYPs) that metabolize xenobiotics are expressed and active in the brain. These CYPs contribute to the metabolism of many centrally acting compounds, including clinically used drugs, drugs of abuse, and neurotoxins. Although CYP levels are lower in the brain than in the liver, they may influence central substrate and metabolite concentrations, which could alter resulting centrally-mediated responses to these compounds. Additionally, xenobiotic metabolizing CYPs are highly variable due to genetic polymorphisms and regulation by endogenous and xenobiotic molecules. In the brain, these CYPs are sensitive to xenobiotic induction. As a result, CYPs in the brain vary widely, including among humans, and this CYP variation may influence central metabolism and resulting response to centrally acting compounds. It has been demonstrated, using experimental manipulation of CYP activity in vivo selectively within the brain, that CYP metabolism in the brain alters central substrate and metabolite concentrations, as well as drug response and neurotoxic effects. This suggests that variability in xenobiotic metabolizing CYPs in the human brain may meaningfully contribute to individual differences in response to, and effects of, centrally acting drugs and neurotoxins. This chapter will provide an overview of CYP expression in the brain, endogenous- and xenobiotic-mediated CYP regulation, and the functional impact of CYP-mediated metabolism of drugs and neurotoxins in the brain, with a focus on experimental approaches in mice, rats, and non-human primates, and a discussion regarding the potential role of xenobiotic metabolizing CYPs in the human brain.

Toxicology and pharmacology of botulinum and tetanus neurotoxins: an update

Tetanus and botulinum neurotoxins cause the neuroparalytic syndromes of tetanus and botulism, respectively, by delivering inside different types of neurons, metalloproteases specifically cleaving the SNARE proteins that are essential for the release of neurotransmitters. Research on their mechanism of action is intensively carried out in order to devise improved therapies based on antibodies and chemical drugs. Recently, major results have been obtained with human monoclonal antibodies and with single chain antibodies that have allowed one to neutralize the metalloprotease activity of botulinum neurotoxin type A1 inside neurons. In addition, a method has been devised to induce a rapid molecular evolution of the metalloprotease domain of botulinum neurotoxin followed by selection driven to re-target the metalloprotease activity versus novel targets with respect to the SNARE proteins. At the same time, an intense and wide spectrum clinical research on novel therapeutics based on botulinum neurotoxins is carried out, which are also reviewed here.

Identification of apparently neurotoxic metabolites from assemblages of marine filamentous cyanobacteria associated with the intoxication of captive bottlenose dolphins (Tursiops truncatus) in the Florida Keys

Intoxications of captive bottlenose dolphins (Tursiops truncatus) in the Florida Keys have been linked to observed interactions with marine macrophytic algal and cyanobacterial communities within enclosures. Taxonomic characterization of these communities coupled, in turn, to available observational data collected during intoxication events point to a contribution of filamentous cyanobacterial assemblages comprised of members of the polyphyletic genus, Lyngbya sensu lato. To identify toxic metabolites possibly relevant to these intoxications, chemical screening for known neurotoxins from cyanobacteria, as well as other regionally relevant harmful algal bloom (HAB) taxa, was combined with toxicity testing, and subsequent bioassay-guided fractionation, employing early life stages (i.e., embryos and larvae) of zebrafish (Danio rerio) as a well-established aquatic vertebrate toxicological model. Chemical analyses did not detect (within analytical limits) any of the known algal or cyanobacterial neurotoxins. Toxicity testing, alongside bioassay-guided fractionation, however, identified several chemical fractions with a range of potentially relevant bioactivities in both zebrafish embryos and post-hatch larvae including, in particular, behavioral (e.g., aberrant swimming) and physiological (e.g., altered heart rate) endpoints indicative of possible neurotoxicity, and subsequent chemical characterization of fractions suggested a contribution of the previously identified bioactive metabolite, eudesmacarbonate, in the observed toxicity. Comparative toxicological assessment with PbTx-2, as a positive control for neurotoxicity in the zebrafish model, further supported neurotoxic activity of cyanobacterial metabolites potentially relevant, in turn, to a contribution of these metabolites to dolphin intoxications. These findings suggest, in general, that marine zoological facilities may be affected by regional HABs, and assessments of potentially toxigenic algae and cyanobacteria should be included in management strategies in these facilities.

Spider Neurotoxins as Modulators of NMDA Receptor Signaling

Molecules that selectively act on N-methyl-D-aspartate (NMDA) receptors may have a multidirectional effect by modulating the activity of NMDARs, affecting their active sites as well as by changing the composition of their subunits. The results of the clinical trials conducted so far in mood disorders and schizophrenia indicate that such agents may become new effective drugs for the treatment of these diseases. Number of spider neurotoxins e.g. ctenitoxins extracted from Phoneutria sp. venom act as potent and selective NMDAR blockers that do not disturb cortical and hippocampal glutamate signaling, LTP generation and synaptic neurochemistry. Possibly this intriguing kind of promising neuroregulatory peptides and polyamines can be clinically applicable in a wide spectrum of neuropsychiatric disorders, including epilepsy, neurotrauma and ischemic injuries. These novel medications can potentially be helpful in the future treatment of stroke and several neurodegenerative diseases.

Connecting the dots between mitochondrial dysfunction and Parkinson's disorder: focus mitochondria-targeting therapeutic paradigm in mitigating the disease severity

Mitochondria are unique cell organelles, which exhibit multifactorial roles in numerous cell physiological processes, significantly preserving the integrity of neural synaptic interconnections, mediating ATP production, and regulating apoptotic signaling pathways and calcium homeostasis. Multiple neurological disorders occur as a consequence of impaired mitochondrial functioning, with greater sensitivity of dopaminergic (DA) neurons to mitochondrial dysfunction, due to oxidative nature and low mitochondrial mass, thus supporting the contribution of mitochondrial impairment in Parkinson's disorder (neuronal damage due to curbed dopamine levels). The pathophysiology of the second most common disorder, PD, is potentiated by various mitochondrial homeostasis regulating genes, as discussed in the review. The PD symptoms are known to be aggravated by multiple mitochondria-linked alterations, like reactive oxygen species (ROS) production, Ca2+ buffering, imbalanced mitochondrial dynamics (fission, fusion, mitophagy), biogenetic dysfunctions, disrupted mitochondrial membrane potential (MMP), protein aggregation, neurotoxins, and genetic mutations, which manifest the central involvement of unhealthy mitochondria in neurodegeneration, resulting in retarded DA neurons in region of substantia nigra pars compacta (SNpc), causing PD. Furthermore, the review tends to target altered mitochondrial components, like oxidative stress, inflammation, biogenetic alterations, impaired dynamics, uncontrolled homeostasis, and genetic mutations, to provide a sustainable and reliable alternative in PD therapeutics and to overcome the pitfalls of conventional therapeutic agents. Therefore, the authors elaborate the relationship between PD pathogenesis and mitochondrial dysfunctions, followed by a suitable mitochondria-targeting therapeutic portfolio, as well as future considerations, aiding the researchers to investigate novel strategies to mitigate the severity of the disease.

Neurotoxicity of Olindias sambaquiensis and Chiropsalmus quadrumanus extracts in sympathetic nervous system

Cnidarians are equipped with nematocysts, which are specialized organelles used to inoculate venom during prey capturing and defense. Their venoms are rich in toxins and a potential source of bioactive compounds, however, poorly explored so far. In this work, the activity of the methanolic extracts from the hydromedusa Olindias sambaquiensis and the cubozoan jellyfish Chiropsalmus quadrumanus were studied in sympathetic neurotransmission. For that, bisected rat vas deferens - a classic model of sympathetic neurotransmission - were incubated with the extracts for further myographic and histopathological analysis. The O. sambaquiensis extract, at 0.1 μg/mL, facilitated the neurogenic contractions of the noradrenergic-rich epididymal portion, while reducing the noradrenaline (NA) potency, which suggests an interaction with postsynaptic α₁-adrenoceptors. On the other hand, a higher concentration (1 μg/mL) leads to time- and frequency-dependent blockade of nerve-evoked contractions without significantly changing the response to exogenous NA. In turn, the C. quadrumanus extract at 0.1 μg/mL induced blockade of nerve-evoked noradrenergic contractions while reducing the potency to exogenous NA. Both extracts did not affect the purinergic neurotransmission or induce muscle damages. Our results demonstrate that O. sambaquiensis and C. quadrumanus extracts significantly interfere with the noradrenergic neurotransmission without altering purinergic response or smooth muscle structure on rat vas deferens. Such results bring to light the pharmacological potential of O. sambaquiensis and C. quadrumanus molecules for therapeutics focusing on noradrenergic neurotransmission.

Toxins from harmful algae in fish from Scottish coastal waters

Harmful algal bloom events are increasing in a number of water bodies around the world with significant economic impacts on the aquaculture, fishing and tourism industries. As well as their potential impacts on human health, toxin exposure from harmful algal blooms (HABs) has resulted in widespread morbidity and mortality in marine life, including top marine predators. There is therefore a need for an improved understanding of the trophic transfer, and persistence of toxins in marine food webs. For the first time, the concentrations of two toxin groups of commercial and environmental importance, domoic acid (DA) and saxitoxin (including Paralytic Shellfish Toxin (PST) analogues), were measured in the viscera of 40 different fish species caught in Scotland between February and November, 2012 to 2019. Overall, fish had higher concentrations of DA compared to PSTs, with a peak in the summer / autumn months. Whole fish concentrations were highest in pelagic species including Atlantic mackerel and herring, key forage fish for marine predators including seals, cetaceans and seabirds. The highest DA concentrations were measured along the east coast of Scotland and in Orkney. PSTs showed highest concentrations in early summer, consistent with phytoplankton bloom timings. The detection of multiple toxins in such a range of demersal, pelagic and benthic fish prey species suggests that both the fish, and by extension, piscivorous marine predators, experience multiple routes of toxin exposure. Risk assessment models to understand the impacts of exposure to HAB toxins on marine predators therefore need to consider how chronic, low-dose exposure to multiple toxins, as well as acute exposure during a bloom, could lead to potential long-term health effects ultimately contributing to mortalities. The potential synergistic, neurotoxic and physiological effects of long-term exposure to multiple toxins require investigation in order to appropriately assess the risks of HAB toxins to fish as well as their predators.

Effect of environmental toxicants on neuronal functions

In the last few years, neurodegenerative diseases like Alzheimer's disease (AD) and Parkinson's disease (PD) have attracted attention due to their high prevalence worldwide. Environmental factors may be one of the biggest reasons for these diseases related to neuronal dysfunctions. Most of neuronal disorders are strongly associated with pre- and postnatal exposure to environmental toxins released from industries. Some of the neurotoxic metals such as lead, aluminum, mercury, manganese, cadmium, and arsenic as well as some pesticides and metal-based nanoparticles have been involved in AD and PD due to their ability to produce senile/amyloid plaques and NFTs which are the main feature of these neuronal dysfunctions. Exposure to solvents is also majorly responsible for neurodegenerative disorders. The present review highlights the impact of omnipresent heavy metals with some other neurotoxins on human health and how they give rise to neuronal dysfunctions which in turn causes socio-economic consequences due to increasing pollution worldwide. Graphical abstract.

Advanced Techniques for the Use of Neurotoxins in Non-Surgical Facial Rejuvenation

BACKGROUND

Neurotoxins initially were used to treat hyperfunctional rhytids of the face, but now have been expanded to improve facial shaping, correct facial asymmetry and even improve skin texture and tone.

METHODS

The clinical approach to non-surgical facial rejuvenation is approached into four anatomical regions: the upper face, midface, lower face and neck.

RESULTS

The key muscles of the upper face include frontalis, orbicularis oculi, corrugator supercilii, procerus, depressor supercilii and temporalis. The muscles in the midface to be discussed include the levator labii superioris, levator labii superioris alaeque nasi, depressor anguli oris, depressor septi nasi and nasalis. Treatment of the lower face focuses on the orbicularis oris, mentalis, depressor anguli oris and masseter muscles. Finally, treatment of the neck region will be reviewed with emphasis on platysmal bands and necklace lines as well as the Nefertiti lift.

CONCLUSIONS

Non-surgical facial rejuvenation using neurotoxins should be performed safely and effectively in order to avoid and treat complications.

LEVEL OF EVIDENCE V

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Diversity of the Genomes and Neurotoxins of Strains of Clostridium botulinum Group I and Clostridium sporogenes Associated with Foodborne, Infant and Wound Botulism

Clostridium botulinum Group I and Clostridium sporogenes are closely related bacteria responsible for foodborne, infant and wound botulism. A comparative genomic study with 556 highly diverse strains of C. botulinum Group I and C. sporogenes (including 417 newly sequenced strains) has been carried out to characterise the genetic diversity and spread of these bacteria and their neurotoxin genes. Core genome single-nucleotide polymorphism (SNP) analysis revealed two major lineages; C. botulinum Group I (most strains possessed botulinum neurotoxin gene(s) of types A, B and/or F) and C. sporogenes (some strains possessed a type B botulinum neurotoxin gene). Both lineages contained strains responsible for foodborne, infant and wound botulism. A new C. sporogenes cluster was identified that included five strains with a gene encoding botulinum neurotoxin sub-type B1. There was significant evidence of horizontal transfer of botulinum neurotoxin genes between distantly related bacteria. Population structure/diversity have been characterised, and novel associations discovered between whole genome lineage, botulinum neurotoxin sub-type variant, epidemiological links to foodborne, infant and wound botulism, and geographic origin. The impact of genomic and physiological variability on the botulism risk has been assessed. The genome sequences are a valuable resource for future research (e.g., pathogen biology, evolution of C. botulinum and its neurotoxin genes, improved pathogen detection and discrimination), and support enhanced risk assessments and the prevention of botulism.

Protective role of anticancer drugs in neurodegenerative disorders: A drug repurposing approach

The disease heterogeneity and little therapeutic progress in neurodegenerative diseases justify the need for novel and effective drug discovery approaches. Drug repurposing is an emerging approach that reinvigorates the classical drug discovery method by divulging new therapeutic uses of existing drugs. The common biological background and inverse tuning between cancer and neurodegeneration give weight to the conceptualization of repurposing of anticancer drugs as novel therapeutics. Many studies are available in the literature, which highlights the success story of anticancer drugs as repurposed therapeutics. Among them, kinase inhibitors, developed for various oncology indications evinced notable neuroprotective effects in neurodegenerative diseases. In this review, we shed light on the salient role of multiple protein kinases in neurodegenerative disorders. We also proposed a feasible explanation of the action of kinase inhibitors in neurodegenerative disorders with more attention towards neurodegenerative disorders. The problem of neurotoxicity associated with some anticancer drugs is also highlighted. Our review encourages further research to better encode the hidden potential of anticancer drugs with the aim of developing prospective repurposed drugs with no toxicity for neurodegenerative disorders.

Quantification of cylindrospermopsin, anatoxin-a and homoanatoxin-a in cyanobacterial bloom freshwater using direct injection/SPE coupled with UPLC-MS/MS

Analytical methods based on direct injection (DI) and solid phase extraction (SPE) coupled with ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC- MS/MS) were developed for the determination of anatoxin-a (ATX-a), cylindrospermopsin (CYN), and homoanatoxin-a (HATX-a) in freshwater samples impacted with cyanobacterial blooms. The presence of CYN in freshwater samples was detected and quantified based on direct injection method, while ATX-a and HATX-a could be determined by both DI and SPE-based methods. Matrix effects (ME) on the signal intensity of the cyanotoxins were systematically evaluated for both direct injection and SPE extract samples. CYN, ATX-a, and HATX-a suffered a significant suppression during UPLC-MS/MS. The selection of internal standards (ISs) for compensating/correcting the losses of target cyanotoxins during sample preparation and matrix effects in UPLC-MS/MS analyses were systematically evaluated. Acetaminophen-d₄ (an isotopically labelled acetaminophen) is a suitable internal standard for correcting the ME on the signal intensity of ATX-a and HATX-a, while the use of L-phenylalanine-d₅ or caffeine-d₉ as IS for correcting ME of these toxins was not efficient, as expected. The method detection limit (MDL) for the target cyanotoxins ranged from 0.6 to 15 ng/L, which is sensitive enough to detect the presence of these toxins in cyanobacterial bloom freshwater. The developed methods were successfully applied for routine monitoring of the occurrence of these cyanotoxins in a local water body. Monitoring results depicted that ATX-a, CYN and HATX-a were ubiquitously detected in water samples, at concentrations ranging from 70 to 24,600 ng/L.

Associations of the Behavioral Assessment and Research System (BARS) neurobehavioral outcomes with attention problems in children living near coal ash storage sites

Environmental exposures have been linked to childhood problems with overactivity, attention, and impulse control, and an increased risk of attention deficit hyperactivity disorder (ADHD) diagnosis. Two approaches to identify these types of exposure-related neurobehavioral problems include the use of computerized tests, such as the Behavioral Assessment and Research System (BARS), as well as the use of behavior rating scales. To assess comparability of these two types of measures, we analyzed data from 281 children aged 6 to 14 years enrolled in a 5-year research study investigating coal ash exposure and neurobehavioral health. All children lived in proximity of coal ash storage sites. We administered six computer tests from the BARS and obtained behavior measures from the parent-completed Child Behavior Checklist (CBCL) ADHD DSM oriented scale. BARS test performance was associated with age indicating that the tests could be used to evaluate neurodevelopmental changes over time or across a wide age range. Tests within the BARS including Continuous Performance (CPT) false alarm (standardized estimate 1.57, 95% confidence interval (CI) (0.67, 2.48), adjusted p = 0.006), Selective Attention (SAT) wrong count (standardized estimate 2.8, 95% CI (1.17, 4.44), adjusted p = 0.006), and SAT proportion correct (standardized estimate -2.45, 95% CI (-4.01, -0.88), adjusted p = 0.01) were associated with attention and impulse control problems on the CBCL after adjustment for multiple comparisons. Findings support that the BARS can contribute to research on environmental exposures by assessing subclinical behaviors related to ADHD such as sustained attention, impulse control, response inhibition, associative learning, and short-term memory. Future research can examine relationships of these BARS measures with biomarkers of neurotoxic exposures related to living near coal ash storage sites to better identify the potential risk for ADHD-related behaviors among children living near coal ash storage sites.

Multiple neuroprotective features of Scutellaria pinnatifida-derived small molecule

Parkinson's disease (PD) is one of the most prevalent neurodegenerative disorders with no precise etiology. Multiple lines of evidence support that environmental factors, either neurotoxins or neuroinflammation, can induce Parkinsonism. In this study, we purified an active compound, neobaicalein (Skullcapflavone II), from the roots of Scutellaria pinnatifida (S. pinnatifida). Neobaicalein not only had protective impacts on rotenone-induced neurotoxicity but in glial cultures, it dampened the inflammatory response when stimulated with lipopolysaccharide (LPS). Neobaicalein had high antioxidant activity without any obvious toxicity. In addition, it could raise the cell viability, decrease early apoptosis, reduce the generation of reactive oxygen species (ROS), and keep the neurite's length normal in the treated SH-SY5Y cells. Pathway enrichment analysis (PEA) and target prediction provided insights into the PD related genes, protein-protein interaction (PPI) network, and the key proteins enriched in the signaling pathways. Furthermore, docking simulation (DS) on the proteins of the PD-PPI network revealed that neobaicalein might interact with the key proteins involved in PD pathology, including MAPK14, MAPK8, and CASP3. It also blocks the destructive processes, such as cell death, inflammation, and oxidative stress pathways. Our results demonstrate that neobaicalein alleviates pathological effects of factors related to PD, and may provide new insight into PD therapy.

Evolutionary Interpretations of Nicotinic Acetylcholine Receptor Targeting Venom Effects by a Clade of Asian Viperidae Snakes

Ecological variability among closely related species provides an opportunity for evolutionary comparative studies. Therefore, to investigate the origin and evolution of neurotoxicity in Asian viperid snakes, we tested the venoms of Azemiops feae, Calloselasma rhodostoma, Deinagkistrodon acutus, Tropidolaeums subannulatus, and T. wagleri for their relative specificity and potency upon the amphibian, lizard, bird, rodent, and human α-1 (neuromuscular) nicotinic acetylcholine receptors. We utilised a biolayer interferometry assay to test the binding affinity of these pit viper venoms to orthosteric mimotopes of nicotinic acetylcholine receptors binding region from a diversity of potential prey types. The Tropidolaemus venoms were much more potent than the other species tested, which is consistent with the greater prey escape potential in arboreal niches. Intriguingly, the venom of C. rhodostoma showed neurotoxic binding to the α-1 mimotopes, a feature not known previously for this species. The lack of prior knowledge of neurotoxicity in this species is consistent with our results due to the bias in rodent studies and human bite reports, whilst this venom had a greater binding affinity toward amphibian and diapsid α-1 targets. The other large terrestrial species, D. acutus, did not display any meaningful levels of neurotoxicity. These results demonstrate that whilst small peptide neurotoxins are a basal trait of these snakes, it has been independently amplified on two separate occasions, once in Azemiops and again in Tropidolaemus, and with Calloselasma representing a third possible amplification of this trait. These results also point to broader sources of novel neuroactive peptides with the potential for use as lead compounds in drug design and discovery.

Minimally Invasive Facial Cosmetic Procedures

Minimally invasive procedures including neurotoxins, dermal fillers, deoxycholic acid, lasers, peels, and microneedling offer powerful, less permanent adjuncts to surgery that are highly effective in select patients. Injectables and skin resurfacing techniques target facial irregularities including wrinkles and fine lines, decrease in volume and contour, and unwanted fat. Determining the best approach for a given patient involves careful consideration of the patient's health conditions, unique anatomic characteristics, tissue quality, and desired results. A detailed understanding of facial anatomy, aesthetics, and techniques is necessary to master these approaches. This article addresses the spectrum of nonsurgical cosmetic procedures to rejuvenate and optimize the face.

Revisiting Polybia paulista wasp venom using shotgun proteomics - Insights into the N-linked glycosylated venom proteins

The partial proteome of Polybia paulista wasp venom was previously reported elsewhere using a gel-dependent approach and resulted in the identification of a limited number of venom toxins. Here, we reinvestigated the P. paulista venom using a gel-free shotgun proteomic approach; the highly dynamic range of this approach facilitated the detection and identification of 1673 proteins, of which 23 venom proteins presented N-linked glycosylation as a posttranslational modification. Three different molecular forms of PLA1 were identified as allergenic proteins, and two of these forms were modified by N-linked glycosylation. This study reveals an extensive repertoire of hitherto undescribed proteins that were classified into the following six different functional groups: (i) typical venom proteins; (ii) proteins related to the folding/conformation and PTMs of toxins; (iii) proteins that protect toxins from oxidative stress; (iv) proteins involved in chemical communication; (v) housekeeping proteins; and (vi) uncharacterized proteins. It was possible to identify venom toxin-like proteins that are commonly reported in other animal venoms, including arthropods such as spiders and scorpions. Thus, the findings reported here may contribute to improving our understanding of the composition of P. paulista venom, its envenoming mechanism and the pathologies experienced by the victim after the wasp stinging accident. BIOLOGICAL SIGNIFICANCE: The present study significantly expanded the number of proteins identified in P. paulista venom, contributing to improvements in our understanding of the envenoming mechanism produced by sting accidents caused by this wasp. For example, novel wasp venom neurotoxins have been identified, but no studies have assessed the presence of this type of toxin in social wasp venoms. In addition, 23 N-linked glycosylated venom proteins were identified in the P. paulista venom proteome, and some of these proteins might be relevant allergens that are immunoreactive to human IgE.

The accumulation dynamics, elimination and risk assessment of paralytic shellfish toxins in fish from a water supply reservoir

Paralytic shellfish Toxins (PSTs) or saxitoxins are neurotoxins that block the neural transmission by binding to the voltage-gated sodium channels in the nerve cells. There are >50 analogues described, which could be biotransformed into a molecular form of greater or lesser toxicity. The Alagados Reservoir is used for water supply, and persistent cyanobacterial blooms as well as PSTs concentrations have been found in this water body since 2002. The aims of this study were to quantify the concentrations of PSTs in the water and fish samples from the Alagados Reservoir. In addition, we evaluated the elimination of PSTs for 90 days in fish and estimated the potential risk to human health. Water and fish samples were collected from the reservoir. For the water samples the phytoplankton and chemical analyses were carried out. Fish were divided into two sample times: Field Samples (FS) and Elimination Experiment Samples (EES), which were maintained for 90 days in filtered and dechlorinated water. For chemical analysis, the muscles of FS were collected on the fish sampling day and the muscles and feces of EES were collected at 7, 15, 30, 45, 60, 75 and 90 days. PSTs concentrations were present in water and fish samples, and they were estimated as a potential risk to humans; mainly for children. In addition, toxins were accumulated, biotransformed to other analogues and excreted by the fish. However, after 90 days, the toxins were still present in the water and fish muscle. Therefore, PSTs can remain for a long period in water, and fish can be a carrier of these neurotoxins. New approaches of monitoring and management are necessary in the actual global context of cyanobacteria and cyanotoxins.

Toxic exposures and the senses of taste and smell

This review addresses the adverse influences of neurotoxic exposures on the ability to smell and taste. These chemical senses largely determine the flavor of foods and beverages, impact food intake, and ultimately nutrition, and provide a warning for spoiled or poisonous food, leaking natural gas, smoke, airborne pollutants, and other hazards. Hence, toxicants that damage these senses have a significant impact on everyday function. As noted in detail, a large number of toxicants encountered in urban and industrial air pollution, including smoke, solvents, metals, and particulate matter can alter the ability to smell. Their influence on taste, i.e., sweet, sour, bitter, salty, and savory (umami) sensations, is not well documented. Given the rather direct exposure of olfactory receptors to the outside environment, olfaction is particularly vulnerable to damage from toxicants. Some toxicants, such as nanoparticles, have the potential to damage not only the olfactory receptor cells, but also the central nervous system structures by their entrance into the brain through the olfactory mucosa.

The analgesic effect of intraarticular OnabotulinumtoxinA in a female murine model of collagenase induced chronic degenerative monoarthritis

Purpose

We previously reported the efficacy of intraarticular (IA) rimabotulinumtoxinB (BoNT/B) in a murine model of chronic degenerative arthritis pain. This study aimed to measure the analgesic effects of onabotulinumtoxinA (BoNT/A) on collagenase induced chronic degenerative arthritis joint pain.

Methods

Chronic degenerative arthritis was produced by IA injection of 10 μl collagenase (Col) (10 IU) into the left knee of C57BL/6J female mice 4 weeks prior to pain assessment. IA BoNT/A was injected 3 days before testing. Arthritis pain was measured as evoked pain scores (EPS) and spontaneous pain behaviors with an advanced dynamic weight bearing (ADWB) device. EPS was a tally of fights and vocalizations exhibited in one minute with knee palpation. Percent body weight and percent time spent on each limb was quantified. All mice were 12 weeks old at the time of examination.

Results

IA Col increased EPS and reduced ADWB measures of percent weight bearing on the left hind limb compared to naïve mice. BoNT/A treatment reduced EPS and increased weight bearing on the left hind limb. The improvements were not significant compared to the Col group. There was no significant difference in time spent on the left hind limb between any treatment groups. Forelimb ADWB measures of percent weight and time in arthritic mice significantly increased compared to nonarthritic animals. Treatment with BoNT/A in the arthritic limb decreased this offloading; however, statistical analysis only showed significance in weightbearing.

Conclusion

IA Col monoarthritis increased evoked and spontaneous pain behaviors in female mice after four weeks. Treatment with IA BoNT/A decreased pain behaviors but only forelimb weight bearing showed a significant improvement. This led us to conclude that treatment with BoNT/A is not an effective analgesic for the treatment of chronic degenerative knee arthritis in murine models.

Reconsideration of the immunotherapeutic pediatric safe dose levels of aluminum

FDA regulations require safety testing of constituent ingredients in drugs (21 CFR 610.15). With the exception of extraneous proteins, no component safety testing is required for vaccines or vaccine schedules. The dosing of aluminum in vaccines is based on the production of antibody titers, not safety science. Here we estimate a Pediatric Dose Limit that considers body weight. We identify several serious historical missteps in past analyses of provisional safe levels of aluminum in vaccines, and provide updates relevant to infant aluminum exposure in the pediatric schedule considering pediatric body weight. When aluminum doses are estimated from Federal Regulatory Code given body weight, exposure from the current vaccine schedule are found to exceed our estimate of a weight-corrected Pediatric Dose Limit. Our calculations show that the levels of aluminum suggested by the currently used limits place infants at risk of acute, repeated, and possibly chronic exposures of toxic levels of aluminum in modern vaccine schedules. Individual adult exposures are on par with Provisional Tolerable Weekly Intake "limits", but some individuals may be aluminum intolerant due to genetics or previous exposures. Vaccination in neonates and low birth-weight infants must be re-assessed; other implications for the use of aluminum-containing vaccines, and additional limitations in our understanding of neurotoxicity and safety levels of aluminum in biologics are discussed.

Microbial production of toxins from the scorpion venom: properties and applications

Scorpion venom are composed mainly of bioactive proteins and peptides that may serve as lead compounds for the design of biotechnological tools and therapeutic drugs. However, exploring the therapeutic potential of scorpion venom components is mainly impaired by the low yield of purified toxins from milked venom. Therefore, production of toxin-derived peptides and proteins by heterologous expression is the strategy of choice for research groups and pharmaceutical industry to overcome this limitation. Recombinant expression in microorganisms is often the first choice, since bacteria and yeast systems combine high level of recombinant protein expression, fast cell growth and multiplication and simple media requirement. Herein, we present a comprehensive revision, which describes the scorpion venom components that were produced in their recombinant forms using microbial systems. In addition, we highlight the pros and cons of performing the heterologous expression of these compounds, regarding the particularities of each microorganism and how these processes can affect the application of these venom components. The most used microbial system in the heterologous expression of scorpion venom components is Escherichia coli (85%), and among all the recombinant venom components produced, 69% were neurotoxins. This review may light up future researchers in the choice of the best expression system to produce scorpion venom components of interest.

d-galactose and aluminium chloride induced rat model with cognitive impairments

Cognitive impairments and cholinergic dysfunctions have been well reported in old age disorders including Alzheimer's disease (AD). d-galactose (D-gal) has been reported as a senescence agent while aluminium act as a neurotoxic metal, but little is known about their combined effects at different doses. The aim of this study was to establish an animal model with cognitive impairments by comparing the effects of different doses of co-administrated D-gal and aluminium chloride (AlCl₃). In this study male albino wistar rats were administered with D-gal 60 mg/kg.bwt intra peritoneally (I.P) injected and AlCl₃ (100, 200, or 300 mg/kg.bwt.) was orally administered once daily for 10 consecutive weeks. Performance of the rats were evaluated through behavioural assessments; Morris water maze (MWM) and open field tests (OFT); histopathological examination was performed on the hippocampus; moreover biochemical measurements of acetylcholinesterase (AChE) and hyperphosphorylated tau protein (p-tau) were examined. The results of this experiment on rats treated with D-gal 60 + AlCl₃ 200 mg/kg.bwt showed near ideal cognitive impairments. The rats exhibited an obvious memory and learning deficits, marked neuronal loss in hippocampus, showed increase in AChE activities and high expression of p-tau within the tissues of the brain. This study concludes that D-gal 60 + AlCl₃ 200 mg/kg.bwt as the ideal dose for mimicking AD like cognitive impairments in albino wistar rats. It is also crucial to understand the pathogenesis of this neurodegenerative disease and for drug discovery.

What are the main environmental factors driving the development of the neurotoxic dinoflagellate Vulcanodinium rugosum in a Mediterranean ecosystem (Ingril lagoon, France)?

Vulcanodinium rugosum, a dinoflagellate developing in Ingril Lagoon (Mediterranean, France) is responsible for shellfish intoxications due to the neurotoxin pinnatoxin G. A one year survey (March 2012-April 2013) was conducted in this oligotrophic shallow lagoon and key environmental parameters were recorded (temperature, salinity and nutrients). The spatio-temporal distribution of V. rugosum in water column and on macrophytes was also determined. Planktonic cells of V. rugosum were observed at all sampling stations, but in relatively low concentrations (maximum of 1000 cell/L). The highest abundances were observed from June to September 2012. There was a positive correlation between cell densities and both temperature and salinity. Non-motile cells were detected on macrophytes, with a maximum concentration of 6300 cells/g wet weight. Nitrite and ammonium were negatively related to V. rugosum abundance whereas total nitrogen, total phosphorus and phosphates showed a positive correlation. Altogether, in situ results suggest that V. rugosum is rather thermophilic and that organic nutrients should be considered when studying the nutrition requirements for this noxious expanding dinoflagellate.

Electrophysiological Recordings of Evoked End-Plate Potential on Murine Neuro-muscular Synapse Preparations

Neuromuscular junction (NMJ) is the specialized chemical synapse that mediates the transmission of the electrical impulse running along motor neuron axons to skeletal muscle fibers. NMJ is the best characterized chemical synapse and its study along many years of research has provided most of the general knowledge of synapse development, structure and functionality. Electrophysiology is the most accurate experimental procedure to study NMJ physiology and it largely contributed to the elucidation of synaptic transmission basic principles. Many electrophysiological techniques have been developed to study NMJ physiology and physiopathology. In this paper, we describe an ex vivo tissue preparation for electrophysiology that can be applied to investigate nerve-muscle transmission functionality in mice. It is routinely used in our laboratory to study presynaptic neurotoxins, antitoxins, and to monitor NMJ degeneration and regeneration. This is a broadly applicable technique which can also be adopted to investigate alterations of NMJ activity in mouse models of neuromuscular diseases, including peripheral neuropathies, motor neuron disorders and myasthenic syndromes.

Neurotoxins as Preclinical Models for Parkinson's Disease

Translational medicine is one of the major concerns in this century. While significant advances have been made with scientific knowledge, the translation of their promising results has not led to any new therapies. In Parkinson's disease, a long list of clinical studies, based on preclinical models with exogenous neurotoxins, has failed. Therefore, the aim of this opinion paper is to open discussion about preclinical models for Parkinson's disease based on neurotoxins.

OnabotulinumtoxinA (Botox) in the Treatment of Crow's Feet Lines in Japanese Subjects

Background

This study evaluated the safety and efficacy of onabotulinumtoxinA in Japanese subjects with crow’s feet lines (CFL).

Methods

This phase 3, multicenter, double-blind, randomized study included 2 treatment periods: 6-month placebo-controlled period followed by a 7-month open-label period. In period 1, subjects with moderate to severe CFL received onabotulinumtoxinA 24 U (n = 104) or 12 U (n = 99), or placebo (n = 97). In period 2, placebo subjects switched to onabotulinumtoxinA 24 U or 12 U (double-blind dose). Up to 5 total treatments were permitted for subjects meeting re-treatment criteria. The primary efficacy measure was the proportion of investigator-assessed responders (achieving CFL severity of none or mild at maximum smile using the Facial Wrinkle Scale with Asian Photonumeric Guide [FWS-A] at day 30 of treatment 1). Additional endpoints included other responders (achieving at least 1-grade improvement at maximum smile and at rest using the FWS-A at day 30), responders at other time points, duration of effect, subject-reported outcomes, and safety.

Results

All efficacy endpoints were met. At day 30, the proportion of subjects achieving none or mild severity at maximum smile was significantly greater (P < 0.001) in the onabotulinumtoxinA 24 and 12 U groups (68.3 and 56.6%, respectively) compared with the placebo group (8.2%). Efficacy results were consistent over repeated treatments, and subjects’ self-assessed outcomes were similar to investigator-assessed results.

Conclusions

Treatment with onabotulinumtoxinA 24 and 12 U improved the appearance of CFL in Japanese subjects and was well tolerated, with no new safety findings.

Level of Evidence I

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Neurotoxins from Clostridium botulinum (serotype A) isolated from the soil of Mendoza (Argentina) differ from the A-Hall archetype and from that causing infant botulism

The type A of neurotoxin produced by Clostridium botulinum is the prevalent serotype in strains of Mendoza. The soil is the main reservoir for C.botulinum and is possibly one of the infection sources in infant botulism. In this study, we characterized and compared autochthonous C. botulinum strains and their neurotoxins. Bacterial samples were obtained from the soil and from fecal samples collected from children with infant botulism. We first observed differences in the appearance of the colonies between strains from each source and with the A Hall control strain. In addition, purified neurotoxins of both strains were found to be enriched in a band of 300 kDa, whereas the A-Hall strain was mainly made up of a band of ∼600 kDa. This finding is in line with the lack of hemagglutinating activity of the neurotoxins under study. Moreover, the proteolytic activity of C. botulinum neurotoxins was evaluated against SNARE (soluble N-ethylmaleimide-sensitive factor-attachment protein receptor) proteins from rat brain. It was observed that both, SNAP 25 (synaptosomal-associated protein 25) and VAMP 2 (vesicle-associated membrane protein) were cleaved by the neurotoxins isolated from the soil strains, whereas the neurotoxins from infant botulism strains only induced a partial cleavage of VAMP 2. On the other hand, the neurotoxin from the A-Hall strain was able to cleave both proteins, though at a lesser extent. Our data indicate that the C.botulinum strain isolated from the soil, and its BoNT, exhibit different properties compared to the strain obtained from infant botulism patients, and from the A-Hall archetype.

Overview of Botulinum Toxins for Aesthetic Uses

Botulinum toxin type A (BTA) can be used for facial aesthetics. The 3 currently available BTA types include onabotulinumtoxinA (Botox; Botox Cosmetic, Allergan, Irvine, CA), abobotulinumtoxinA (Dysport; Ipsen, Ltd, Berkshire, UK), and incobotulinumtoxinA (Xeomin; Merz Pharmaceuticals, Frankfurt, Germany). The mechanism of action and clinical uses for treatment of dynamic lines of the forehead, brow, glabella, lateral orbit, nose, and lips are presented, as well as treatment of masseter hypertrophy, platysmal bands, and improvements of the perioral region. Specific BTA injection sites and suggested doses are presented.

MPV17-related hepatocerebral mitochondrial DNA depletion syndrome (MPV17-NNH) revisited

MPV17-related hepatocerebral mitochondrial DNA depletion syndrome (previously known as Navajo neurohepatopathy) was discovered in children in the Four Corner's region of New Mexico approximately 40 years ago. This disease is associated with a single missense mutation in exon 2 in the MPV17 gene. The syndrome has now been recognized world-wide. We find that huge quantities of neurotoxins were present in archived nervous tissues from such patients. Arsenic was increased 18 ×, cadmium ~ 10 ×, cobalt 2.5 × and manganese 2.3 ×; the largest increase was in mercury content 16,000 × compared to contemporaneous fresh-frozen normal nervous tissues. In the Four Corner's region of NM the life span is reduced compared to other parts of the United States and in our patients with MPV17-NNH the average life span was 5.4 years ± 2.7 (SE) years. We now live in the Anthropocene an epoch characterized by large additions to the biosphere of neurotoxins. The effects of such toxic loads on human health and disease remain to be assessed. We speculate how such high neurotoxin content in tissues, which is likely to increase during the Anthropocene, may have influenced MPV17-NNH and similar phenotypes in different parts of the world. Our results imply that selenium supplementation to the diet in the Four Corner's region of NM might be beneficial to normal people and in the management of patients with MPV17-NNH syndrome.

Environmental factors in the development of autism spectrum disorders

Autism spectrum disorders (ASD) are highly heterogeneous developmental conditions characterized by deficits in social interaction, verbal and nonverbal communication, and obsessive/stereotyped patterns of behavior and repetitive movements. Social interaction impairments are the most characteristic deficits in ASD. There is also evidence of impoverished language and empathy, a profound inability to use standard nonverbal behaviors (eye contact, affective expression) to regulate social interactions with others, difficulties in showing empathy, failure to share enjoyment, interests and achievements with others, and a lack of social and emotional reciprocity. In developed countries, it is now reported that 1%-1.5% of children have ASD, and in the US 2015 CDC reports that approximately one in 45 children suffer from ASD. Despite the intense research focus on ASD in the last decade, the underlying etiology remains unknown. Genetic research involving twins and family studies strongly supports a significant contribution of environmental factors in addition to genetic factors in ASD etiology. A comprehensive literature search has implicated several environmental factors associated with the development of ASD. These include pesticides, phthalates, polychlorinated biphenyls, solvents, air pollutants, fragrances, glyphosate and heavy metals, especially aluminum used in vaccines as adjuvant. Importantly, the majority of these toxicants are some of the most common ingredients in cosmetics and herbicides to which almost all of us are regularly exposed to in the form of fragrances, face makeup, cologne, air fresheners, food flavors, detergents, insecticides and herbicides. In this review we describe various scientific data to show the role of environmental factors in ASD.

Enzyme-luminescence method: Tool for real-time monitoring of natural neurotoxins in vitro and l-glutamate release from primary cortical neurons

•

We describe the applicability of our previously developed novel enzyme-luminescence method for rapid and sensitive detection of natural neurotoxins (e.g., shellfish and mushroom toxins) using brain model cells (C6 glioma cells) in vitro.

•

A racemic mixtures of the gonyautoxins (GTX), including GTX2,3 and GTX1,4 were used for evaluating the inhibition effects of these toxins on glutamate release from the C6 glioma cells. The potency was compared based on IC₅₀ values.

•

The activation effect of ibotenic acid (a mushroom toxin) on glutamate release from C6 cells was also evaluated. The potency was compared based on EC₅₀ values.

•

We also tested the applicability of our system for real-time detection of glutamate release from primary rat cortical neurons instead of model cells.

•

This novel detection technique may be also applicable in determining neuronal differentiation ratio as well finding glutamatergic neurons without immunostaining in situ.

•

This sensing tool may also has a great potential for the investigation of the effects of various growth factors and chemicals on neuronal differentiation, neurotransmitter dynamics, neurodegeneration, and synaptogenesis.

Novel enzyme-luminescence method is used for the rapid and sensitive in vitro detection of natural neurotoxins (e.g., shellfish and mushroom toxins) using model brain cells. Paralytic shellfish poisons gonyautoxins (e.g., GTX2,3 and GTX1,4) were detected at 1 nM level by their inhibition of glutamate release from C6 glioma cells upon drug stimulation (IC₅₀: GTX2,3 = 30 nM and GTX1,4 = 8 nM). Activation of glutamate release from C6 cells by ibotenic acid (a mushroom toxin) was also evaluated (EC₅₀ = 10 nM). The method was tested for real-time detection of glutamate release from primary rat cortical neurons. Dose-dependent effects of KCl (0–200 mM) and NMDA on glutamate release from primary cortical neurons were studied. The effects of different culture conditions on K⁺-depolarization-induced glutamate release were also investigated. The method may be applicable to screening of drugs and toxins, and finding glutamatergic neurons in brain slices without in situ staining.

Neuroteratology and Animal Modeling of Brain Disorders

Over the past 60 years, a large number of selective neurotoxins were discovered and developed, making it possible to animal-model a broad range of human neuropsychiatric and neurodevelopmental disorders. In this paper, we highlight those neurotoxins that are most commonly used as neuroteratologic agents, to either produce lifelong destruction of neurons of a particular phenotype, or a group of neurons linked by a specific class of transporter proteins (i.e., dopamine transporter) or body of receptors for a specific neurotransmitter (i.e., NMDA class of glutamate receptors). Actions of a range of neurotoxins are described: 6-hydroxydopamine (6-OHDA), 6-hydroxydopa, DSP-4, MPTP, methamphetamine, IgG-saporin, domoate, NMDA receptor antagonists, and valproate. Their neuroteratologic features are outlined, as well as those of nerve growth factor, epidermal growth factor, and that of stress. The value of each of these neurotoxins in animal modeling of human neurologic, neurodegenerative, and neuropsychiatric disorders is discussed in terms of the respective value as well as limitations of the derived animal model. Neuroteratologic agents have proven to be of immense importance for understanding how associated neural systems in human neural disorders may be better targeted by new therapeutic agents.

[A rare cause of acute respiratory failure]

This article describes a case report on a rare cause of acute respiratory failure. The patient suffered from a rapidly progressing respiratory insufficiency due to intoxication with a neurotoxin (botulism). A rapid diagnosis proved to be very difficult due to the rarity of the disease itself and the difficulties encountered in the clinical examination caused by early initiation of intubation, artificial ventilation and analgosedation.

Tityus serrulatus venom--A lethal cocktail

Tityus serrulatus (Ts) is the main scorpion species of medical importance in Brazil. Ts venom is composed of several compounds such as mucus, inorganic salts, lipids, amines, nucleotides, enzymes, kallikrein inhibitor, natriuretic peptide, proteins with high molecular mass, peptides, free amino acids and neurotoxins. Neurotoxins are considered the most responsible for the envenoming syndrome due to their pharmacological action on ion channels such as voltage-gated sodium (Nav) and potassium (Kv) channels. The major goal of this review is to present important advances in Ts envenoming research, correlating both the crude Ts venom and isolated toxins with alterations observed in all human systems. The most remarkable event lies in the Ts induced massive releasing of neurotransmitters influencing, directly or indirectly, the entire body. Ts venom proved to extremely affect nervous and muscular systems, to modulate the immune system, to induce cardiac disorders, to cause pulmonary edema, to decrease urinary flow and to alter endocrine, exocrine, reproductive, integumentary, skeletal and digestive functions. Therefore, Ts venom possesses toxins affecting all anatomic systems, making it a lethal cocktail. However, its low lethality may be due to the low venom mass injected, to the different venom compositions, the body characteristics and health conditions of the victim and the local of Ts sting. Furthermore, we also described the different treatments employed during envenoming cases. In particular, throughout the review, an effort will be made to provide information from an extensive documented studies concerning Ts venom in vitro, in animals and in humans (a total of 151 references).

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.

Employment of higher doses of botulinum toxin type A to reduce spasticity after stroke

Spasticity is a common disabling symptom for several neurological conditions. Botulinum toxin type A injection represents the gold standard treatment for focal spasticity with efficacy, reversibility, and low prevalence of complications. Current guidelines suggest a dose up to 600 units (U) of onabotulinumtoxinA/incobotulinumtoxinA or up to 1,500 U of abobotulinumtoxinA to treat post-stroke spasticity to avoid important adverse effects. However, recently, higher doses of botulinum toxin type A were employed, especially in case of upper and lower limb severe spasticity. With searches of US National Library of Medicine databases, we identified all studies published from December 1989 to July 2014 concerning the use of higher doses of this neurotoxin for spasticity treatment with at least a dose of 600 U of onabotulinumtoxinA and incobotulinumtoxinA or 1,800 U of abobotulinumtoxinA. The cumulative body of evidence coming from the eight studies selected suggested that higher doses of botulinum toxin type A appeared to be efficacious in reducing spasticity of the upper and lower limbs after stroke, with adverse effects generally mild. However, further investigations are needed to determine the safety and reproducibility in larger case series or randomized clinical trials of higher doses of botulinum toxin type A also after repeated injections.