Venom proteomics and Duvernoy's venom gland histology of Pseudoboa neuwiedii (Neuwied's false boa; Dipsadidae, Pseudoboini).

The venom of Colombian specimens of the rear-fanged snake Pseudoboa neuwiedii contains proteolytic and phospholipase A (PLA) activities, but is devoid of esterases. Mass spectrometric analysis of electrophoretic bands indicated that this venom contains C-type lectins (CTL), cysteine-rich secretory proteins (CRiSP), PLA, snake venom metalloproteinases (SVMP), and snake venom matrix metalloproteinases (svMMP). In this investigation, we extended our characterization of P.

Disruption of exploratory behavior and olfactory memory in cockroaches exposed to sublethal doses of the neonicotinoid Thiamethoxam.

Neonicotinoid insecticides (NNI) are agonists of insect nicotinic acetylcholine receptors (nAChR) that induce non-elucidate mechanisms of abnormal behavior in insects. In this work, we investigated the effects of sublethal doses of the neonicotinoid thiamethoxam (TMX) on neurochemical and physiological parameters in cockroaches. Sublethal doses of TMX (0.

Snakebites by venomous snakes in Brazilian serpentaria and zoos over a 10-year period (2012-2021).

Despite the wide range of institutions that maintain venomous snakes in captivity in Brazil there are no comprehensive data on the occurrence of snakebites and envenomations in these places. We examined the range of native and exotic species of venomous snakes kept by Brazilian zoos and serpentaria (scientific and commercial) and assessed the frequency of snakebites in workers handling these snakes during a 10-year period (2012-2021). Twenty-two (73.

Recent advances on the influence of fipronil on insect behavior.

Fipronil, a pesticide widely used to control agricultural and household insect pests, blocks insect GABA and glutamate (GluCl) ionotropic receptors, resulting in uncontrolled hyperexcitation and paralysis that eventually leads to death. The use of fipronil is controversial because unintentional exposure to this compound may contribute to the ongoing global decline of insect pollinator populations. Although the sublethal effects of fipronil have been linked to aberrant behavior and impaired olfactory learning in insects, the precise mechanisms involved in these responses remain unclear.

The Cloning and Characterization of a Three-Finger Toxin Homolog (NXH8) from the Coralsnake That Interacts with Skeletal Muscle Nicotinic Acetylcholine Receptors.

Coralsnakes ( spp.) are the only elapids found throughout the Americas. They are recognized for their highly neurotoxic venom, which is comprised of a wide variety of toxins, including the stable, low-mass toxins known as three-finger toxins (3FTx).

Biochemical and toxicological profiles of venoms from an adult female South American bushmaster (Lachesis muta rhombeata) and her offspring.

In this work, we compared the biochemical and toxicological profiles of venoms from an adult female specimen of Lachesis muta rhombeata (South American bushmaster) and her seven offspring born in captivity, based on SDS-PAGE, RP-HPLC, enzymatic, coagulant, and hemorrhagic assays. Although adult and juvenile venoms showed comparable SDS-PAGE profiles, juveniles lacked some chromatographic peaks compared with adult venom. Adult venom had higher proteolytic (caseinolytic) activity than juvenile venoms (p < 0.

Involvement of phospholipase A in the neuromuscular blockade caused by coralsnake (Micrurus spp.) venoms in mouse phrenic nerve-diaphragm preparations in vitro.

In this work, we examined the neuromuscular blockade caused by venoms from four South-American coralsnakes (Micrurus altirostris - MA, M. corallinus - MC, M. spixii - MS, and M.

Fipronil affects cockroach behavior and olfactory memory.

Fipronil (Fpl), an insecticide belonging to the class of phenylpyrazoles, is associated with the widespread mortality of pollinator insects worldwide. Based on studies carried out on residual concentrations of Fpl commonly found in the environment, in this study, we evaluated the sublethal effects of Fpl on behavior and other neurophysiological parameters using the cockroach Nauphoeta cinerea as a biological model. Sublethal doses of Fpl (0.

Assessment of local pain and analgesia in envenoming by wandering spiders (Phoneutria spp.).

Phoneutrism (bites by wandering spiders of the genus Phoneutria) frequently results in local pain. We describe a retrospective cohort study of a case series of phoneutrism admitted to our Emergency Department (ED), in which we used the Numeric Pain Rating Scale (NPRS 0-10) to assess the intensity of local pain upon admission, and recorded the analgesic measures used to control this pain. Other criteria for inclusion were: (1) An age ≥8 years, (2) Treatment exclusively at our ED, and (3) Visualization or photographing the spider at the time of the bite and/or bringing the spider for identification.

Cardiac Effects of Micrurus corallinus and Micrurus dumerilii carinicauda (Elapidae) Venoms and Neutralization by Brazilian Coralsnake Antivenom and Varespladib.

In this work, we examined the action of two South American coralsnake (Micrurus corallinus and Micrurus dumerilii carinicauda) venoms on rat heart function in the absence and presence of treatment with Brazilian coralsnake antivenom (CAV) and varespladib (VPL), a potent phospholipase A inhibitor. Anesthetized male Wistar rats were injected with saline (control) or a single dose of venom (1.5 mg/kg, i.

Effect of the phospholipase A inhibitor Varespladib, and its synergism with crotalic antivenom, on the neuromuscular blockade induced by Crotalus durissus terrificus venom (with and without crotamine) in mouse neuromuscular preparations.

The venom of the South American rattlesnake Crotalus durissus terrificus causes an irreversible neuromuscular blockade in isolated preparations due to action of the presynaptically-acting heterodimeric phospholipase A (PLA) crotoxin. Some populations of this subspecies contain, in addition to crotoxin, the toxin crotamine, which acts directly on muscle fibers. In this study we used C.

Partial efficacy of a Brazilian coralsnake antivenom and varespladib in neutralizing distinct toxic effects induced by sublethal Micrurus dumerilii carinicauda envenoming in rats.

In this work, we reported the efficacy of a combination of Brazilian therapeutic coralsnake antivenom (CAV) and varespladib (phospholipase A inhibitor - VPL) in partially neutralizing selected toxic effects of Micrurus dumerilii carinicauda coralsnake venom in rats. Venom caused local myonecrosis and systemic neurotoxicity, nephrotoxicity, and hepatotoxicity within 2 h of injection. CAV and VPL administered separately failed to prevent most of these alterations.

Temporal evolution of dermonecrosis in loxoscelism assessed by photodocumentation.

Background: Although loxoscelism (bites by brown spiders of the genus Loxosceles) frequently results in dermonecrosis, no previous clinical reports have provided detailed temporal photodocumentation of the evolution of dermonecrotic lesions in a case series.

Methods: This was a retrospective cohort study involving a case series of loxoscelism. Only cases of dermonecrosis with photodocumentation of lesion evolution (from admission until complete or almost complete healing) were included.

Action of Varespladib (LY-315920), a Phospholipase A Inhibitor, on the Enzymatic, Coagulant and Haemorrhagic Activities of (South-American Bushmaster) Venom.

Varespladib (VPL) was primarily developed to treat inflammatory disturbances associated with high levels of serum phospholipase A (PLA). VPL has also demonstrated to be a potential antivenom support agent to prevent PLA-dependent effects produced by snake venoms. In this study, we examined the action of VPL on the coagulant, haemorrhagic and enzymatic activities of (South-American bushmaster) venom.

Evaluation of Protection by Caffeic Acid, Chlorogenic Acid, Quercetin and Tannic Acid against the In Vitro Neurotoxicity and In Vivo Lethality of (South American Rattlesnake) Venom.

Systemic envenomation by (South American rattlesnake) can cause coagulopathy, rabdomyolysis, acute kidney injury, and peripheral neuromuscular blockade, the latter resulting in flaccid paralysis. Previous studies have shown that plant products such as tannic acid and theaflavin can protect against the neuromuscular blockade caused by venom in vitro. In this work, we used mouse-isolated phrenic nerve-diaphragm preparations to examine the ability of caffeic acid, chlorogenic acid, and quercetin to protect against venom-induced neuromuscular blockade in vitro.

Are Silver Nanoparticles Useful for Treating Second-Degree Burns? An Experimental Study in Rats.

In this work, the potential usefulness of silver nanoparticles (AgNPs) for treating burn wounds was examined. Second-degree burns were induced in male Wistar rats by touching the skin with a heated (70°C) metallic device for 10 s, after which the animals were randomly allocated to one of two groups: control (n=8, treated with sterile saline) and experimental (n=8, treated with AgNPs, 0.081 mg/mL; 50 µL applied to the burn surface).

Chemical and functional analyses of Rhinella icterica (Spix, 1824) toad secretion screened on contractions of the heart and oviduct in Locusta migratoria.

Rhinella icterica is a Brazilian toad with a parotoid secretion that is toxic to insects. In this work, we examined the entomotoxicity of this secretion in locust (Locusta migratoria) semi-isolated heart and oviduct preparations in vitro. The parotoid secretion caused negative chronotropism in semi-isolated heart preparations (at the highest dose tested: 500 μg) and markedly enhanced the amplitude of spontaneous contractions and tonus of oviduct muscle (0.

Entomotoxicity of jaburetox: revisiting the neurotoxic mechanisms in insects.

Ureases are metalloenzymes that hydrolyze urea to ammonia and carbamate. The main urease isoforms present in the seeds of (jack bean urease - JBU and canatoxin) exert a variety of biological activities. The insecticidal activity of JBU is mediated, at least in part, by jaburetox (Jbtx), a recombinant peptide derived from the JBU amino acid sequence.

Kinetic profile of N,N-dimethyltryptamine and β-carbolines in saliva and serum after oral administration of ayahuasca in a religious context.

Ayahuasca is a beverage obtained from Banisteriopsis caapi plus Psychotria viridis. B. caapi contains the β-carbolines harmine, harmaline, and tetrahydroharmine that are monoamine oxidase inhibitors and P.

Cardiovascular activity of Micrurus lemniscatus lemniscatus (South American coralsnake) venom.

Envenomation by coralsnakes (Micrurus spp.) is characterized by blockade of peripheral neurotransmission mediated by the presence of α- and β-neurotoxins. However, little is known about their cardiovascular activity.

Chemical and Pharmacological Screening of (Spix 1824) Toad Parotoid Secretion in Avian Preparations.

The biological activity of parotoid secretion (RIPS) and some of its chromatographic fractions (RI18, RI19, RI23, and RI24) was evaluated in the current study. Mass spectrometry of these fractions indicated the presence of sarmentogenin, argentinogenin, (5,12)-12,14-dihydroxy-11-oxobufa-3,20,22-trienolide, marinobufagin, bufogenin B, 11α,19-dihydroxy-telocinobufagin, bufotalin, monohydroxylbufotalin, 19-oxo-cinobufagin, 3α,12,25,26-tetrahydroxy-7-oxo-5-cholestane-26--sulfate, and cinobufagin-3-hemisuberate that were identified as alkaloid and steroid compounds, in addition to marinoic acid and -methyl-5-hydroxy-tryptamine. In chick brain slices, all fractions caused a slight decrease in cell viability, as also seen with the highest concentration of RIPS tested.

Neurotoxicity of Tityus bahiensis (brown scorpion) venom in sympathetic vas deferens preparations and neuronal cells.

Systemic scorpion envenomation is characterized by massive neurotransmitter release from peripheral nerves mediated primarily by scorpion venoms neurotoxins. Tityus bahiensis is one of the medically most important species in Brazil, but its venom pharmacology, especially regarding to peripheral nervous system, is poorly understood. Here, we evaluated the T.

Near-fatal poisoning after ricin injection.

Objective: To report a near-fatal poisoning after intentional injection of ricin from a castor bean () extract.

Case Report: A 21 year-old man self-injected ∼3 mL of a castor bean extract intramuscularly and subcutaneously in the left antecubital fossa. Upon admission to our ED (1 h post-exposure; day 1, D1) he was awake and alert, but complained of mild local pain and showed slight local edema and erythema.

Toxinological characterization of venom from Leptodeira annulata (Banded cat-eyed snake; Dipsadidae, Imantodini).

We investigated the histology of Duvernoy's venom gland and the biochemical and biological activities of Leptodeira annulata snake venom. The venom gland had a lobular organization, with secretory tubules formed by serous epithelial cells surrounding each lobular duct. The latter drained into a common lobular duct and subsequently into a central cistern.

Biochemical characterization and cytotoxic effect of the skin secretion from the red-spotted Argentina frog (Anura: Hylidae).

Background: (red-spotted Argentina frog) is a casque-headed tree frog species belonging to the Hylidae family. This species has a complex combination of anti-predator defense mechanisms that include a highly lethal skin secretion. However, biochemical composition and biological effects of this secretion have not yet been studied.