COELENTERATE TOXINS, ITS PHARMACEUTICAL AND THERAPEUTIC EFFECTS

Present review article emphasizes species specific coelenterate toxins, its pharmaceutical and therapeutic effects. Most of the coelenterates inflict venom accidently by using nematocysts found on arms. These animals very quickly do massive and multiple inflictions of venom which causes cardiotoxicity that leads to the death of human beings. Coelenterate venom toxin groups differ in their composition and show diverse biological activity i.e. cytolytic or neurotoxic, hemolytic, anti-parasitic activity, α-amylase inhibitor activity, and analgesic activity anti-cancerous and antitumor activity, anti-inflammatory and antimicrobial activity. Coelenterate venom initiates toxic and immunological reactions exert their effects by modifying the properties of the ion channels involved in action potential generation in nerve, heart, and skeletal muscles. This article suggests available information, on coelenterate toxins could be used to develop potential therapeutic interventions for various human diseases and disorders.

A rare case of Panophthalmitis due to cobra bite

Purpose Ocular manifestations of snake bite are rare, ranging from direct injury to the eye from snake venom or indirect injury due to antivenom. We report a rare case of cobra bite causing panophthalmitis due to indirect injury as a result of snake venom toxin related tissue necrosis and susceptibility to secondary infections. Methods Observational case report. External photographs, slit lamp photos, ultrasonography of the eye and histopathology of the eviscerated eye were used to characterize and describe the clinical findings. Thirty-nine-years-old male farmer presented with history of cobra snake bite on his right index finger and developed right eye sudden onset pain and redness 3 days later. On examination, features were suggestive of panophthalmitis and the eye had to be eviscerated with scleral excision. Conclusion It is important for ophthalmologist to be aware of such grave consequences of snake bite to be prepared for the emergency management of such cases.

Plant Natural Products: A Promising Source of Hyaluronidase Enzyme Inhibitors

Hyaluronidase enzyme degrades hyaluronan, the primary component of the extracellular matrix found in connective tissues animals and on the surface of certain pathogenic bacteria. The degradation of hyaluronan is linked to a wide range of physiological and pathological process. Inhibiting the hyaluronidase enzyme is thus significant as an approach to treat a variety of diseases and health conditions such as anti-fertility, anti-tumor, antimicrobial, and anti-venom/toxin agents. HAase inhibitors of different chemical types have been identified include both synthetic compounds and constituents obtained from naturally sources. Plant natural products as HAase inhibitors are unique due to their structural features and diversity. Medicinal plants have historically been used as contraceptives, antidote for snakebites and to promote wound healing. In recent years, small molecules, particularly plant natural products (alkaloids, flavonoids, polyphenol and flavonoids, triterpenes and steroids) possessing potent HAase have been discovered. A number of plant species from various families, which have folk medicinal claims for these ailments (related to hyaluronan disturbances) were scientifically proven for their potential to block HAase enzymes.

Recruitment of toxin-like proteins with ancestral venom function supports endoparasitic lifestyles of Myxozoa

Cnidarians are the oldest lineage of venomous animals and use nematocysts to discharge toxins. Whether venom toxins have been recruited to support parasitic lifestyles in the Endocnidozoa (Myxozoa + Polypodium) is, however, unknown. To examine this issue we variously employed transcriptomic, proteomic, associated molecular phylogenies, and localisation studies on representative primitive and derived myxozoans (Malacosporea and Myxosporea, respectively), Polypodium hydriforme, and the free-living staurozoan Calvadosia cruxmelitensis. Our transcriptomics and proteomics analyses provide evidence for expression and translation of venom toxin homologs in myxozoans. Phylogenetic placement of Kunitz type serine protease inhibitors and phospholipase A2 enzymes reveals modification of toxins inherited from ancestral free-living cnidarian toxins, and that venom diversity is reduced in myxozoans concordant with their reduced genome sizes. Various phylogenetic analyses of the Kunitz-type toxin family in Endocnidozoa suggested lineage-specific gene duplications, which offers a possible mechanism for enhancing toxin diversification. Toxin localisation in the malacosporean Buddenbrockia plumatellae substantiates toxin translation and thus illustrates a repurposing of toxin function for endoparasite development and interactions with hosts, rather than for prey capture or defence. Whether myxozoan venom candidates are expressed in transmission stages (e.g. in nematocysts or secretory vesicles) requires further investigation.

The Development of Mucosal Immunization as an Alternative Approach for Production of Antisera Against Saw Scale Viper from Sindh

The reported cases of snake bite are 5.4 million per year, making the serious envenoming issue so, that WHO categorises cases of snake bite in neglected tropical diseases. Anti snake venom is produced by intramuscular injection of crude venom with different formulation of adjuvants to equine animals, but these intramuscular injections have several serious health impact in equine. Snake species categorised according to geographical locations, and there is a different composition of the snake venom at different locations. So, this research had been designed and evaluated new oral adjuvant formulation for viper family of Sindh, Pakistan. This is a animal immune based analysis consisting two Saw scale viper from Thar and costal area of Sindh because both have different habitat and morphological appearance. The venom toxin protein, combined with a mineral oil adjuvant for oral immunization. The adjuvant with venom via oral route produced of specific IgG and horse give maximum response with three doses of venom. The antibody titer was measured by ELISA showed significant results in both groups. For confirmation of specific antibodies isolated from horse serum, serum neutalization assay and immunodiffusion test were carried out. The snake venom with oral adjuvant immunization, is safe, efficient and time saving for production of equine Immunoglobulins IgG.

Structure and selectivity engineering of the M1 muscarinic receptor toxin complex

Muscarinic toxins (MTs) are natural toxins produced by mamba snakes that primarily bind to muscarinic acetylcholine receptors (MAChRs) and modulate their function. Despite their similar primary and tertiary structures, MTs show distinct binding selectivity toward different MAChRs. The molecular details of how MTs distinguish MAChRs are not well understood. Here, we present the crystal structure of M1AChR in complex with MT7, a subtype-selective anti-M1AChR snake venom toxin. The structure reveals the molecular basis of the extreme subtype specificity of MT7 for M1AChR and the mechanism by which it regulates receptor function. Through in vitro engineering of MT7 finger regions that was guided by the structure, we have converted the selectivity from M1AChR toward M2AChR, suggesting that the three-finger fold is a promising scaffold for developing G protein–coupled receptor modulators.

Molecular Modelling and Docking Experiments Examining the Interaction between SARS-CoV-2 Spike Glycoprotein and Neuronal Nicotinic Acetylcholine Receptors

While SARS-CoV-2 uses angiotensin converting enzyme 2 (ACE2) as the receptor for cell entry, it is important to examine for other potential interactions between the virus and other cell receptors. Based on the clinical observation of low smoking prevalence among hospitalized COVID-19 patients, we recently identified a “toxin-like” amino acid (aa) sequence on the receptor binding domain of the spike glycoprotein of SARS-CoV-2 (aa 375-390) with homology to a sequence of a snake venom toxin, which could interact with nicotinic acetylcholine receptors (nAChRs). We now present computational molecular modelling and docking experiments using 3D structures of the SARS-CoV-2 spike glycoprotein and the extracellular domain of the nAChR alpha9 subunit. We identified an interaction between the aa381-386 of the SARS-CoV-2 spike glycoprotein and the aa189-192 of the extracellular domain of the nAChR alpha9 subunit, a region which forms the core of the “toxin-binding site” of the nAChRs. The mode of interaction is very similar to the interaction between the alpha9 nAChR and alpha-bungarotoxin. A similar interaction was observed between the pentameric alpha7 AChR and the SARS-CoV-2 spike glycoprotein. Our findings support the hypothesis that severe COVID-19 may be associated with disruption of the nicotinic cholinergic system which could be caused by an interaction between SARS-CoV-2 and nAChRs.

Nicotinic Cholinergic System and COVID-19: Identification of a Potentially Crucial Snake Toxin-Like Sequence in the SARS-CoV-2 Spike Glycoprotein

Smoking is a risk factor for respiratory infections and there is reasonable concern that it may affect COVID-19 susceptibility and severity. Recent studies have focused on the interaction between smoking (and nicotine) and ACE2 expression, suggesting that ACE2 up-regulation could contribute to enhanced viral cell entry. However, case series have shown that there is an unexpectedly low prevalence of smoking among hospitalized COVID-19 cases. Since early April, we were the first to hypothesize that dysfunction of the nicotinic cholinergic system (NCS) may be implicated in the pathophysiology of severe COVID-19. We recently reported that many of the clinical manifestations of severe COVID-19 could be explained by dysregulation of the NCS. In this study, we present an amino acid sequence in the receptor binding domain of the SARS-CoV-2 Spike glycoprotein which is homologous to a sequence of a snake venom toxin. We present the 3D structural location of this “toxin-like” sequence on the Spike Glycoprotein. These findings suggest that SARS-CoV-2 could potentially interact with acetylcholine receptors causing dysregulation of the NCS and the cholinergic anti-inflammatory pathway.