Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 13.442
Filtrar
1.
Ecotoxicol Environ Saf ; 281: 116678, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38964067

RESUMEN

The non-protein amino acid ß-N-methylamino-L-alanine (BMAA), produced by cyanobacteria, has been recognized as a neurotoxin. L-serine as an antagonist of BMAA can effectively alleviate BMAA-induced neurotoxicity. Although BMAA has long been emphasized as a neurotoxin, with the emergence of BMAA detected in a variety of algae in freshwater around the world and its clear biological enrichment effect, it is particularly important to study the non-neurotoxic adverse effects of BMAA. However, there is only limited evidence to support the ability of BMAA to cause oxidative damage in the liver. The exact molecular mechanism of BMAA-induced liver injury is still unclear. The formation of neutrophil extracellular traps (NETs) is a 'double-edged sword' for the organism, excessive formation of NETs is associated with inflammatory diseases of the liver. Our results innovatively confirmed that BMAA was able to cause the formation of NETs in the liver during the liver injury. The possible mechanism may associated with the regulation of ERK/p38 and cGAS/STING signaling pathways. The massive formation of NETs was able to exacerbate the BMAA-induced oxidative stress and release of inflammatory factors in the mice liver. And the removal of NETs could alleviate this injury. This article will bring a new laboratory evidence for BMAA-induced non-neurotoxicity and immunotoxicity.


Asunto(s)
Aminoácidos Diaminos , Enfermedad Hepática Inducida por Sustancias y Drogas , Toxinas de Cianobacterias , Trampas Extracelulares , Estrés Oxidativo , Animales , Aminoácidos Diaminos/toxicidad , Trampas Extracelulares/efectos de los fármacos , Ratones , Estrés Oxidativo/efectos de los fármacos , Masculino , Neutrófilos/efectos de los fármacos , Hígado/efectos de los fármacos , Neurotoxinas/toxicidad , Transducción de Señal/efectos de los fármacos
3.
Cell Chem Biol ; 31(7): 1233-1235, 2024 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-39029451

RESUMEN

In this issue of Cell Chemical Biology, Elleman et al.1 introduce a transformative chemical approach to control neuronal activity with high spatial and temporal resolution. The authors present STX-bpc, a potent neurotoxin that naturally inhibits voltage-gated sodium channels (NaVs), complementing available optogenetic methods for manipulating neuronal activity, cellular communication, and behavior.


Asunto(s)
Neuronas , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Neuronas/citología , Animales , Humanos , Optogenética , Canales de Sodio Activados por Voltaje/metabolismo , Canales de Sodio Activados por Voltaje/química , Neurotoxinas/farmacología , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacología , Bloqueadores del Canal de Sodio Activado por Voltaje/química
4.
Toxins (Basel) ; 16(6)2024 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-38922166

RESUMEN

The larvae of some lampyrid beetles are highly specialized predators of snails. They have been observed to climb on the shells of their prey and use this exposed position to bite and inject secretions potentially originating from the midgut. Besides serving the purpose of extra-oral digestion (EOD), injected compounds also seem to have a paralyzing effect. Up to now, the toxins causing this paralyzing activity have not been identified. In the current study, we provide a first compositional analysis of the midgut secretion from lampyrid larvae, with a focus on identifying putative neurotoxins causing the observed paralyzing effect. For this purpose, we utilized a combined proteo-transcriptomic approach to characterize the compounds present in the midgut secretion of larval stages of Lampyris noctiluca. In terms of the absolute numbers of identified compounds, the midgut secretion is dominated by hydrolyzing enzymes comprising peptidases, carboxylesterases, and glycosidases. However, when considering expression levels, a few rather short cysteine-rich peptides exceed all other compounds. Some of these compounds show moderate similarity to putative neurotoxins identified in the venom of other arthropods and could be responsible for paralyzing effects. In addition to these potential toxins, we provide a list of peptides typical of the midgut secretion of L. noctiluca, supplemented by the corresponding precursor sequences.


Asunto(s)
Escarabajos , Larva , Neurotoxinas , Caracoles , Animales , Larva/metabolismo , Neurotoxinas/toxicidad , Neurotoxinas/metabolismo , Escarabajos/metabolismo , Caracoles/metabolismo , Conducta Predatoria
5.
Front Cell Infect Microbiol ; 14: 1394713, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38836054

RESUMEN

The rabies virus enters the nervous system by interacting with several molecular targets on host cells to modify behavior and trigger receptor-mediated endocytosis of the virion by poorly understood mechanisms. The rabies virus glycoprotein (RVG) interacts with the muscle acetylcholine receptor and the neuronal α4ß2 subtype of the nicotinic acetylcholine receptor (nAChR) family by the putative neurotoxin-like motif. Given that the neurotoxin-like motif is highly homologous to the α7 nAChR subtype selective snake toxin α-bungarotoxin (αBTX), other nAChR subtypes are likely involved. The purpose of this study is to determine the activity of the RVG neurotoxin-like motif on nAChR subtypes that are expressed in brain regions involved in rabid animal behavior. nAChRs were expressed in Xenopus laevis oocytes, and two-electrode voltage clamp electrophysiology was used to collect concentration-response data to measure the functional effects. The RVG peptide preferentially and completely inhibits α7 nAChR ACh-induced currents by a competitive antagonist mechanism. Tested heteromeric nAChRs are also inhibited, but to a lesser extent than the α7 subtype. Residues of the RVG peptide with high sequence homology to αBTX and other neurotoxins were substituted with alanine. Altered RVG neurotoxin-like peptides showed that residues phenylalanine 192, arginine 196, and arginine 199 are important determinants of RVG peptide apparent potency on α7 nAChRs, while serine 195 is not. The evaluation of the rabies ectodomain reaffirmed the observations made with the RVG peptide, illustrating a significant inhibitory impact on α7 nAChR with potency in the nanomolar range. In a mammalian cell culture model of neurons, we confirm that the RVG peptide binds preferentially to cells expressing the α7 nAChR. Defining the activity of the RVG peptide on nAChRs expands our understanding of basic mechanisms in host-pathogen interactions that result in neurological disorders.


Asunto(s)
Glicoproteínas , Virus de la Rabia , Xenopus laevis , Receptor Nicotínico de Acetilcolina alfa 7 , Receptor Nicotínico de Acetilcolina alfa 7/metabolismo , Animales , Virus de la Rabia/fisiología , Virus de la Rabia/metabolismo , Humanos , Glicoproteínas/metabolismo , Glicoproteínas/genética , Oocitos/metabolismo , Proteínas Virales/metabolismo , Proteínas Virales/genética , Proteínas del Envoltorio Viral/metabolismo , Proteínas del Envoltorio Viral/genética , Interacciones Huésped-Patógeno , Unión Proteica , Rabia/metabolismo , Rabia/virología , Acetilcolina/metabolismo , Acetilcolina/farmacología , Neurotoxinas/metabolismo , Neurotoxinas/farmacología
6.
Nature ; 631(8019): 142-149, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38926573

RESUMEN

Interindividual genetic variation affects the susceptibility to and progression of many diseases1,2. However, efforts to study how individual human brains differ in normal development and disease phenotypes are limited by the paucity of faithful cellular human models, and the difficulty of scaling current systems to represent multiple people. Here we present human brain Chimeroids, a highly reproducible, multidonor human brain cortical organoid model generated by the co-development of cells from a panel of individual donors in a single organoid. By reaggregating cells from multiple single-donor organoids at the neural stem cell or neural progenitor cell stage, we generate Chimeroids in which each donor produces all cell lineages of the cerebral cortex, even when using pluripotent stem cell lines with notable growth biases. We used Chimeroids to investigate interindividual variation in the susceptibility to neurotoxic triggers that exhibit high clinical phenotypic variability: ethanol and the antiepileptic drug valproic acid. Individual donors varied in both the penetrance of the effect on target cell types, and the molecular phenotype within each affected cell type. Our results suggest that human genetic background may be an important mediator of neurotoxin susceptibility and introduce Chimeroids as a scalable system for high-throughput investigation of interindividual variation in processes of brain development and disease.


Asunto(s)
Corteza Cerebral , Quimera , Predisposición Genética a la Enfermedad , Neurotoxinas , Organoides , Femenino , Humanos , Masculino , Linaje de la Célula/efectos de los fármacos , Corteza Cerebral/citología , Corteza Cerebral/efectos de los fármacos , Corteza Cerebral/metabolismo , Quimera/genética , Etanol/efectos adversos , Etanol/toxicidad , Variación Genética , Células-Madre Neurales/citología , Células-Madre Neurales/efectos de los fármacos , Células-Madre Neurales/metabolismo , Neurotoxinas/toxicidad , Organoides/citología , Organoides/efectos de los fármacos , Organoides/metabolismo , Fenotipo , Células Madre Pluripotentes/citología , Células Madre Pluripotentes/efectos de los fármacos , Células Madre Pluripotentes/metabolismo , Donantes de Tejidos , Ácido Valproico/efectos adversos , Ácido Valproico/toxicidad , Predisposición Genética a la Enfermedad/genética
7.
Toxins (Basel) ; 16(6)2024 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-38922160

RESUMEN

The growing use of botulinum neurotoxins (BoNTs) for medical and aesthetic purposes has led to the development and marketing of an increasing number of BoNT products. Given that BoNTs are biological medications, their characteristics are heavily influenced by their manufacturing methods, leading to unique products with distinct clinical characteristics. The manufacturing and formulation processes for each BoNT are proprietary, including the potency determination of reference standards and other features of the assays used to measure unit potency. As a result of these differences, units of BoNT products are not interchangeable or convertible using dose ratios. The intrinsic, product-level differences among BoNTs are compounded by differences in the injected tissues, which are innervated by different nerve fiber types (e.g., motor, sensory, and/or autonomic nerves) and require unique dosing and injection sites that are particularly evident when treating complex therapeutic and aesthetic conditions. It is also difficult to compare across studies due to inherent differences in patient populations and trial methods, necessitating attention to study details underlying each outcome reported. Ultimately, each BoNT possesses a unique clinical profile for which unit doses and injection paradigms must be determined individually for each indication. This practice will help minimize unexpected adverse events and maximize efficacy, duration, and patient satisfaction. With this approach, BoNT is poised to continue as a unique tool for achieving individual goals for an increasing number of medical and aesthetic indications.


Asunto(s)
Toxinas Botulínicas , Humanos , Toxinas Botulínicas/uso terapéutico , Toxinas Botulínicas/administración & dosificación , Animales , Neurotoxinas
8.
Toxins (Basel) ; 16(6)2024 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-38922155

RESUMEN

Botulinum neurotoxins (BoNTs) have been used for almost half a century in the treatment of excessive muscle contractility. BoNTs are routinely used to treat movement disorders such as cervical dystonia, spastic conditions, blepharospasm, and hyperhidrosis, as well as for cosmetic purposes. In addition to the conventional indications, the use of BoNTs to reduce pain has gained increased recognition, giving rise to an increasing number of indications in disorders associated with chronic pain. Furthermore, BoNT-derived formulations are benefiting a much wider range of patients suffering from overactive bladder, erectile dysfunction, arthropathy, neuropathic pain, and cancer. BoNTs are categorised into seven toxinotypes, two of which are in clinical use, and each toxinotype is divided into multiple subtypes. With the development of bioinformatic tools, new BoNT-like toxins have been identified in non-Clostridial organisms. In addition to the expanding indications of existing formulations, the rich variety of toxinotypes or subtypes in the wild-type BoNTs associated with new BoNT-like toxins expand the BoNT superfamily, forming the basis on which to develop new BoNT-based therapeutics as well as research tools. An overview of the diversity of the BoNT family along with their conventional therapeutic uses is presented in this review followed by the engineering and formulation opportunities opening avenues in therapy.


Asunto(s)
Toxinas Botulínicas , Humanos , Toxinas Botulínicas/uso terapéutico , Animales , Neurotoxinas/uso terapéutico , Neurotoxinas/química
10.
J Ethnopharmacol ; 332: 118338, 2024 Oct 05.
Artículo en Inglés | MEDLINE | ID: mdl-38759762

RESUMEN

ETHNOPHARMACOLOGICAL RELEVANCE: The Mesobuthus martensii scorpions, called as "Quanxie", are known Chinese medicinal material base on the "Combat poison with poison" strategy for more than one thousand years, and still widely used to treat various diseases according to the Pharmacopoeia of the People's Republic of China nowadays. AIM OF STUDY: The study aims to investigate the similarity of scorpion neurotoxins at the protein level between the juvenile and adult Mesobuthus martensii scorpions as Chinese medicine materials. MATERIALS AND METHODS: The second-, third- and fourth-instar, and adult Mesobuthus martensii scorpions were collected for the characterization of neurotoxin expression through multiple strategic proteomics, including undigested scorpion venom, endopeptidase-digested, and undigested scorpion telson extract for the sample analysis. RESULTS: Based on the known 107 scorpion neurotoxins from the genomic and transcriptomic analysis of adult Mesobuthus martensii scorpions, the multiple strategic proteomics first revealed that neurotoxins exhibited more stability in telson extract than secreted venom. In the reported transcripts of scorpion neurotoxins, approximately 53%, 56%, 66% and 78% of neurotoxins were detected through undigested scorpion venom, the endopeptidase Arg-C-, Lys-C-digested telson extract, and undigested telson extract strategies, respectively. Nearly 79% of scorpion neurotoxins detected in third-instar Mesobuthus martensii scorpions represent the largest number of scorpion neurotoxins from proteomic analysis to date. Moreover, a total of 84% of scorpion neurotoxins were successfully identified at the protein level, and similar neurotoxin expression profiles in second-, third- and fourth-instar, and adult Mesobuthus martensii scorpions were first revealed by the multiple strategic proteomics. CONCLUSION: These findings for the first time demonstrate the similar neurotoxin expression profiles between the juvenile and adult Mesobuthus martensii scorpions as Chinese medicinal material, which would serve as a paradigm for further toxin analysis from different venomous animals.


Asunto(s)
Medicina Tradicional China , Neurotoxinas , Proteómica , Venenos de Escorpión , Escorpiones , Animales , Proteómica/métodos , Animales Ponzoñosos
11.
Luminescence ; 39(5): e4761, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38807512

RESUMEN

The fear of an increase in blood sugar can be very traumatic. Being diabetic either type I or type II leads to a disorder called diabetes distress having traits of stress, depression, and anxiety. Among risk factors of diabetes mellitus heavy and trace metal toxicity emerges as new risk factors reported in many studies. In this study we target toxic metals, viz., Ni2+, Zn2+, and Cu2+, involved in the pathogenesis of diabetes and diabetic stress with naphthazarin esters. The compounds C1-C3 isolated from the leaves and roots of Arnebia guttata were tested for their metal-binding ability in an aqueous medium in UV-Visible and nuclear magnetic resonance (NMR) studies. These probes are well-known naphthoquinones present in the Arnebia species. In the UV-Visible titrations of compounds C1-C3 with Na2+, K2+, Zn2+, Ca2+, Cu2+, Mg2+, Co2+, and Ni2+ ions, significant binding was observed with Ni2+, Cu2+, and Zn2+ ions in MeOH/H2O. There occurs a beautiful formation of red-shifted bands between the 520 to 620 nm range with a synergistic increase in absorbance. Also, the disappearance of proton peaks in the 1H NMR spectrum on addition of metal ions confirmed binding. Compounds C1-C3 isolated from A. guttata came out as potent Ni2+, Zn2+, and Cu2+ sensors that are reportedly involved in islet function and induction of diabetes.


Asunto(s)
Ésteres , Naftoquinonas , Ésteres/química , Naftoquinonas/química , Diabetes Mellitus/metabolismo , Neurotoxinas/química , Neurotoxinas/metabolismo , Agua/química , Estructura Molecular , Hojas de la Planta/química
12.
Environ Pollut ; 353: 124166, 2024 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-38754694

RESUMEN

Potentially toxic cyanobacterial blooms (cyanoHABs) have become a problem in public water supply reservoirs. Temperature rise caused by climate change can increase the frequency and intensity of blooms, which may influence the cyanotoxins concentration in the environment. This study aimed to evaluate the effect of the temperature on the responses of a Neotropical catfish exposed to a neurotoxin-rich cyanobacterial crude extract (Raphidiopsis raciborskii T3). Juveniles of Rhamdia quelen were exposed to four treatments, based on study data: control at 25 °C (C25), control at 30 °C (C30), crude extract equivalent to 105 cells.mL-l of R. raciborskii at 25 °C (CE25) and 30 °C (CE30). After 96 h of exposure, the fish were anesthetized and blood was taken. After euthanasia, the gill, posterior kidney, brain, muscle, liver and gonad were sampled for hematological, biochemical, genotoxic and histopathological biomarker analysis. Liver was sampled for proteomic analysis for identification of proteins related to energy production. Water samples were collected at the beginning and the end of the experiment for neurotoxins quantification. Different parameters in both males and females were altered at CE25, evidencing the effects of neurotoxins in freshwater fish. At CE30, a water warming scenario, more effects were observed in females than at 25 °C, such as activation of saxitoxin metabolism pathway and genotoxicity. More damage to macromolecules was observed in females at the higher temperature, demonstrating that the increase in temperature can aggravate the toxicity of neurotoxins produced by R. raciborskii T3.


Asunto(s)
Bagres , Cianobacterias , Animales , Bagres/fisiología , Temperatura , Microcistinas/toxicidad , Femenino , Masculino , Toxinas de Cianobacterias , Cambio Climático , Neurotoxinas/toxicidad , Toxinas Bacterianas/toxicidad , Toxinas Marinas/toxicidad
13.
Environ Sci Pollut Res Int ; 31(21): 31479-31491, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38635096

RESUMEN

The present study demonstrates the presence of the neurotoxin ß-N-methylamino-L-alanine and its cyanobacterial producers in irrigation water and grains of some cereal plants from farmlands irrigated with Nile River water in Egypt. BMAA detected by LC-MS/MS in phytoplankton samples was found at higher concentrations of free form (0.84-11.4 µg L-1) than of protein-bound form (0.16-1.6 µg L-1), in association with the dominance of cyanobacteria in irrigation water canals. Dominant cyanobacterial species isolated from these irrigation waters including Aphanocapsa planctonica, Chroococcus minutus, Dolichospermum lemmermanni, Nostoc commune, and Oscillatoria tenuis were found to produce different concentrations of free (4.8-71.1 µg g-1 dry weight) and protein-bound (0.1-11.4 µg g-1 dry weight) BMAA. In the meantime, BMAA was also detected in a protein-bound form only in grains of corn (3.87-4.51 µg g-1 fresh weight) and sorghum (5.1-7.1 µg g-1 fresh weight) plants, but not in wheat grains. The amounts of BMAA accumulated in these grains correlated with BMAA concentrations detected in relevant irrigation water canals. The presence of BMAA in cereal grains would constitute a risk to human and animal health upon consumption of contaminated grains. The study, therefore, suggests continuous monitoring of BMAA and other cyanotoxins in irrigation waters and edible plants to protect the public against exposure to such potent toxins.


Asunto(s)
Riego Agrícola , Aminoácidos Diaminos , Grano Comestible , Grano Comestible/química , Humanos , Aminoácidos Diaminos/análisis , Neurotoxinas/análisis , Cianobacterias/metabolismo , Egipto , Monitoreo del Ambiente , Toxinas de Cianobacterias
14.
Toxins (Basel) ; 16(4)2024 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-38668601

RESUMEN

The evolutionary interplay between predator and prey has significantly shaped the development of snake venom, a critical adaptation for subduing prey. This arms race has spurred the diversification of the components of venom and the corresponding emergence of resistance mechanisms in the prey and predators of venomous snakes. Our study investigates the molecular basis of venom resistance in pythons, focusing on electrostatic charge repulsion as a defense against α-neurotoxins binding to the alpha-1 subunit of the postsynaptic nicotinic acetylcholine receptor. Through phylogenetic and bioactivity analyses of orthosteric site sequences from various python species, we explore the prevalence and evolution of amino acid substitutions that confer resistance by electrostatic repulsion, which initially evolved in response to predatory pressure by Naja (cobra) species (which occurs across Africa and Asia). The small African species Python regius retains the two resistance-conferring lysines (positions 189 and 191) of the ancestral Python genus, conferring resistance to sympatric Naja venoms. This differed from the giant African species Python sebae, which has secondarily lost one of these lysines, potentially due to its rapid growth out of the prey size range of sympatric Naja species. In contrast, the two Asian species Python brongersmai (small) and Python bivittatus (giant) share an identical orthosteric site, which exhibits the highest degree of resistance, attributed to three lysine residues in the orthosteric sites. One of these lysines (at orthosteric position 195) evolved in the last common ancestor of these two species, which may reflect an adaptive response to increased predation pressures from the sympatric α-neurotoxic snake-eating genus Ophiophagus (King Cobras) in Asia. All these terrestrial Python species, however, were less neurotoxin-susceptible than pythons in other genera which have evolved under different predatory pressure as: the Asian species Malayopython reticulatus which is arboreal as neonates and juveniles before rapidly reaching sizes as terrestrial adults too large for sympatric Ophiophagus species to consider as prey; and the terrestrial Australian species Aspidites melanocephalus which occupies a niche, devoid of selection pressure from α-neurotoxic predatory snakes. Our findings underline the importance of positive selection in the evolution of venom resistance and suggest a complex evolutionary history involving both conserved traits and secondary evolution. This study enhances our understanding of the molecular adaptations that enable pythons to survive in environments laden with venomous threats and offers insights into the ongoing co-evolution between venomous snakes and their prey.


Asunto(s)
Boidae , Electricidad Estática , Animales , Boidae/genética , Boidae/fisiología , Neurotoxinas/genética , Neurotoxinas/química , Filogenia , Venenos Elapídicos/genética , Venenos Elapídicos/química , Venenos Elapídicos/toxicidad , Receptores Nicotínicos/genética , Receptores Nicotínicos/metabolismo , Conducta Predatoria , Venenos de Serpiente/genética , Venenos de Serpiente/química
15.
Brain Res ; 1836: 148952, 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-38643930

RESUMEN

Given that global prevalence of Parkinson's disease (PD) is expected to rise over the next few decades, understanding the mechanisms and causes of PD is critical. With emphasis on gut-brain axis, we sought to assess the impact of gentisic acid (GA), a diphenolic compound generated from benzoic acid, in rotenone (Rot) induced PD model in zebrafish. For thirty days, adult zebrafish were exposed to GA and rotenone. Tox-Track program was used to analyze locomotor behaviors in the control, GA, Rot, and Rot + GA groups. LC-MS/MS was performed in brain and intestinal tissues. Proteome Discoverer 2.4 was used to analyze raw files, peptide lists were searched against Danio rerio proteins. Protein interactions or annotations were obtained from STRING database. Tyrosine hydroxylase (Th) staining was performed immunohistochemically in the brain. PD-related gene expressions were determined by RT-PCR. Lipid peroxidation, nitric oxide, superoxide dismutase, glutathione S-transferase, and acetylcholinesterase were measured spectrophotometrically. Improved locomotor behaviors were observed by GA treatment in Rot group as evidenced by increased average speed, exploration rate, and total distance. 5214 proteins were identified in intestinal tissues, 4114 proteins were identified in brain by LC-MS/MS. Rotenone exposure altered protein expressions related to oxidative phosphorylation in brain and intestines. Protein expressions involved in ferroptis and actin cytoskeleton changed in brain and intestines. Altered protein expressions were improved by GA. GA ameliorated Th-immunoreactivity in brain, improved park2, park7, pink1, and lrrk2 expressions. Our results show that GA may be a candidate agent to be evaluated for its potential protective effect for PD.


Asunto(s)
Eje Cerebro-Intestino , Encéfalo , Modelos Animales de Enfermedad , Fármacos Neuroprotectores , Rotenona , Pez Cebra , Animales , Fármacos Neuroprotectores/farmacología , Rotenona/toxicidad , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Eje Cerebro-Intestino/efectos de los fármacos , Eje Cerebro-Intestino/fisiología , Neurotoxinas/toxicidad , Enfermedad de Parkinson/metabolismo , Enfermedad de Parkinson/tratamiento farmacológico , Locomoción/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos
16.
Artículo en Inglés | MEDLINE | ID: mdl-38670246

RESUMEN

In the ongoing evolutionary arms race between predators and prey, adaptive innovations often trigger a reciprocal response. For instance, the emergence of α-neurotoxins in snake venom has driven prey species targeted by these snakes to evolve sophisticated defense mechanisms. This study zeroes in on the particular motifs within the orthosteric sites of post-synaptic nicotinic acetylcholine receptors (nAChR) that confer resistance to α-neurotoxins, often through structural alterations of nAChR. This research examined Australian agamid lizards, a primary prey group for Australian elapid snakes, which are subject to predatory selection pressures. We previously showed that Pogona vitticeps (Central bearded dragon) was resistant to α-neurotoxic snake venoms through a steric hindrance form resistance evolving within the nAChR orthosteric, specifically through the 187-189NVT motif resulting in the presence of N-glycosylation, with the branching carbohydrate chains impeding the binding by the neurotoxins. This adaptive trait is thought to be a compensatory mechanism for the lizard's limited escape capabilities. Despite the significance of this novel adaptation, the prevalence and evolutionary roots of such venom resistance in Australian agamids have not been thoroughly investigated. To fill this knowledge gap, we undertook a comprehensive sequencing analysis of the nAChR ligand-binding domain across the full taxonomical diversity of Australian agamid species. Our findings reveal that the N-glycosylation resistance mechanism is a trait unique to the Pogona genus and absent in other Australian agamids. This aligns with Pogona's distinctive morphology, which likely increases vulnerability to neurotoxic elapid snakes, thereby increasing selective pressures for resistance. In contrast, biolayer interferometry experiments with death adder (Acanthophis species) venoms did not indicate any resistance-related binding patterns in other agamids, suggesting a lack of similar resistance adaptations, consistent with these lineages either being fast-moving, covered with large defensive spines, or being arboreal. This research not only uncovers a novel α-neurotoxin resistance mechanism in Australian agamids but also highlights the complex dynamics of the predator-prey chemical arms race. It provides a deeper understanding of how evolutionary pressures shape the interactions between venomous snakes and their prey.


Asunto(s)
Lagartos , Receptores Nicotínicos , Animales , Lagartos/fisiología , Lagartos/metabolismo , Glicosilación , Receptores Nicotínicos/metabolismo , Receptores Nicotínicos/genética , Australia , Neurotoxinas/toxicidad , Conducta Predatoria/efectos de los fármacos , Proteínas de Reptiles/metabolismo , Proteínas de Reptiles/genética , Filogenia
17.
Mol Ecol ; 33(9): e17358, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38625740

RESUMEN

How do chemically defended animals resist their own toxins? This intriguing question on the concept of autotoxicity is at the heart of how species interactions evolve. In this issue of Molecular Ecology (Molecular Ecology, 2024, 33), Bodawatta and colleagues report on how Papua New Guinean birds coopted deadly neurotoxins to create lethal mantles that protect against predators and parasites. Combining chemical screening of the plumage of a diverse collection of passerine birds with genome sequencing, the researchers unlocked a deeper understanding of how some birds sequester deadly batrachotoxin (BTX) from their food without poisoning themselves. They identified that birds impervious to BTX bear amino acid substitutions in the toxin-binding site of the voltage-gated sodium channel Nav1.4, whose function is essential for proper contraction and relaxation of vertebrate muscles. Comparative genetic and molecular docking analyses show that several of the substitutions associated with insensitivity to BTX may have become prevalent among toxic birds through positive selection. Intriguingly, poison dart frogs that also co-opted BTX in their lethal mantles were found to harbour similar toxin insensitivity substitutions in their Nav1.4 channels. Taken together, this sets up a powerful model system for studying the mechanisms behind convergent molecular evolution and how it may drive biological diversity.


Asunto(s)
Animales Ponzoñosos , Batracotoxinas , Pájaros Cantores , Animales , Batracotoxinas/genética , Neurotoxinas/toxicidad , Neurotoxinas/genética , Passeriformes/genética , Anuros/genética , Canal de Sodio Activado por Voltaje NAV1.4/genética , Sustitución de Aminoácidos , Ranas Venenosas
18.
Mar Pollut Bull ; 202: 116299, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38581736

RESUMEN

The neurotoxin ß-N-methylamino-L-alanine (BMAA) has emerged as an environmental factor related to neurodegenerative diseases. BMAA is produced by various microorganisms including cyanobacteria and diatoms, in diverse ecosystems. In the diatom Phaeodactylum tricornutum, BMAA is known to inhibit growth. The present study investigated the impact of BMAA on the diatom Thalassiosira pseudonana by exposing it to different concentrations of exogenous BMAA. Metabolomics was predominantly employed to investigate the effect of BMAA on T. pseudonana, and MetaboAnalyst (https://www.metabo-analyst.ca/) was used to identify BMAA-associated metabolisms/pathways in T. pseudonana. Furthermore, to explore the unique response, specific metabolites were compared between treatments. When the growth was obstructed by BMAA, 17 metabolisms/pathways including nitrogen and glutathione (i.e. oxidative stress) metabolisms, were influenced in T. pseudonana. This study has further determined that 11 out of 17 metabolisms/pathways could be essentially affected by BMAA, leading to the inhibition of diatom growth.


Asunto(s)
Aminoácidos Diaminos , Toxinas de Cianobacterias , Diatomeas , Metabolómica , Neurotoxinas , Diatomeas/efectos de los fármacos , Neurotoxinas/toxicidad
19.
Pestic Biochem Physiol ; 201: 105853, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38685212

RESUMEN

Ion channels on cell membrane are molecular targets of more than half peptide neurotoxins from spiders. From Pardosa pseudoannulata, a predatory spider on a range of insect pests, we characterized a peptide neurotoxin PPTX-04 with an insecticidal activity. PPTX-04 showed high toxicity to Nilaparvata lugens, a main prey of P. pseudoannulata, and the toxicity was not affected by the resistance to etofenprox (IUPAC chemical name:1-ethoxy-4-[2-methyl-1-[(3-phenoxyphenyl)methoxy]propan-2-yl]benzene, purity: 99%). On N. lugens voltage-gated sodium channel NlNav1 expressed in Xenopus oocytes, PPTX-04 prolonged the channel opening and induced tail currents, which is similar to pyrethroid insecticides. However, PPTX-04 potency on NlNav1 was not affected by mutations conferring pyrethroid resistance in insects, which revealed that PPTX-04 and pyrethroids should act on different receptors in NlNav1. In contrast, two mutations at the extracellular site 4 significantly reduced PPTX-04 potency, which indicated that PPTX-04 would act on a potential receptor containing the site 4 in NlNav1. The result from the molecular docking supported the conclusion that the binding pocket of PPTX-04 in NlNav1 should contain the site 4. In summary, PPTX-04 had high insecticidal activity through acting on a distinct receptor site in insect Nav, and was a potential resource to control insect pests and manage resistance to pyrethroids.


Asunto(s)
Insecticidas , Neurotoxinas , Venenos de Araña , Arañas , Canales de Sodio Activados por Voltaje , Animales , Insecticidas/farmacología , Insecticidas/química , Venenos de Araña/química , Venenos de Araña/farmacología , Venenos de Araña/genética , Canales de Sodio Activados por Voltaje/metabolismo , Canales de Sodio Activados por Voltaje/genética , Neurotoxinas/farmacología , Neurotoxinas/toxicidad , Piretrinas/farmacología , Hemípteros/efectos de los fármacos , Oocitos/efectos de los fármacos , Xenopus laevis , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , Proteínas de Insectos/química
20.
Microb Biotechnol ; 17(4): e14468, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38635158

RESUMEN

The sweet potato whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) is responsible for significant crop losses and presents one of the greatest challenges for global agricultural pest management. Management of whitefly populations and associated plant viral diseases is hindered by widespread whitefly resistance to chemical insecticides. An alternative control approach involves the use of insect-specific neurotoxins, but these require delivery from the whitefly gut into the haemocoel. Here we demonstrate that the coat protein (CP) of a begomovirus, Tomato yellow leaf curl virus, is sufficient for delivery of fused proteins into the whitefly haemocoel without virion assembly. Following feeding on the recombinant CP-P-mCherry fusion (where -P- is a proline-rich linker), mCherry fluorescence was detected in the dorsal aorta and pericardial cells of the whitefly, but not in those of whitefly fed on negative control treatments, indicating effective CP-mediated delivery of mCherry into the whitefly haemocoel. Significant mortality was observed in whiteflies fed on a fusion of CP-P to the insect-specific neurotoxin Hv1a, but not in whiteflies fed on CP-P fused to a disarmed Hv1a mutant. Begomovirus coat protein - insect neurotoxin fusions hold considerable potential for transgenic resistance to whitefly providing valuable tools for whitefly management.


Asunto(s)
Hemípteros , Virus de Plantas , Animales , Neurotoxinas , Agricultura , Fluorescencia
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA