جستجوی مقالات مرتبط با کلیدواژه « ونوم » در نشریات گروه « پزشکی »

Brittle stars can produce well-known toxins responsible for various of their biological activities in addition to their physical defense. The purpose of this study was to identify secondary metabolites and assess the anticholinesterase activities of the crude venom of the Persian Gulf Ophiocoma erinaceous (brittle star) in vitro and in silico due to the abundance of this marine life on the Persian Gulf coasts and with knowledge of their numerous biological effects.

In this study, after the lyophilization of the brittle star sample, an LD50 test, a test of cholinesterase inhibitory activities, identification of the secondary metabolites, and their in-silico evaluations were performed by, respectively, Spearman-Karber, the Ellman spectroscopic method, Gas Chromatography–Mass Spectrometry (GC-MS), and computational docking method.

According to the results, the LD50 value of the sample was 6.04±0.13 (mg/kg). The IC50 values related to their Acetylcholinesterase and  Butyrylcholinesterase were 37.925 ±0.055 and 5.388±0.02 (μg/ml), respectively, compared to the galantamine standard. The GC-MS analysis of the sample showed 25 bioactive chemical compositions with different structures, such as alkaloids, terpenes, and steroids. The computational results of the compounds also confirmed the experimental results. Among these, the alkaloidal compound BS4, had the highest affinity for both enzymes.

As for toxicity potency, the brittle star crude venom sample was classified in the highly toxic category. The GC analysis of the crude venom showed various bioactive secondary metabolites with different chemical structures. The experimental and computational results on the anticholinesterase activities of the sample showed that the venom acts as a significant inhibitor of both enzymes. Further studies are required to determine whether the compound BS4 could be a candidate for the treatment of Alzheimer’s disease.

A surprisingly large number of sea snail species are venomous. Cone snail venoms are produced in a lengthy tubular duct from a complex venom gland and form a cocktail of many toxins, particularly conotoxins which have high potency and specificity for their target specific receptors. They inhibit various channels, neuromuscular receptors or hormones of the victim, and interfere in the transmitted signals of the prey, or dissuade predators. Cone snails have an amazing ability to quickly convert between two different types of defense-evoked and predation-evoked venoms in response to defensive or predatory stimuli. Various conotoxins and conopeptides such as α-conotoxins, σ-conotoxins, ω-conotoxins, μ-conotoxins, ψ-conotoxins, τ-conotoxins, δ-conotoxins, κ-conotoxins and conkunitzins, conantokins, contryphans, Ac1 conotoxins, conoinsulins, granulin-like conotoxins from conoides; augerpeptides derived from the venom peptide family Terebridae; turripeptides from the venom peptide family Turridae; crassipeptides venom peptides from Crassispirids; clathurellipeptides from venomous micro-conoides Clathurellidae, and other toxins such as RFamide peptides and endogenous neuropeptide-like peptides such as conopressins, as well as contulakins have been found in cone snail venoms, which have demonstrated remarkable biological and pharmacological functions. Given the approval of some conotoxins, such as the analgesic medication ziconitide (Prialt®) in clinical trials as well as their biomedical potential, current research has focused on these toxins. The use of integrated venomics approaches has dramatically accelerated the detection of conotoxin sequences. It is anticipated that a better understanding and identification of conotoxins and other toxins derived from other sea snails will lead to their use for the treatment of diseases to which humans have succumbed.

Sea snakes belong to Hydrophiidae family mainly are found in tropical and subtropical waters of the world including the Persian Gulf. Their highly lethal venoms are more potent than snakes with terrestrial origin and contain complex mixtures of organic and inorganic bioactive substances, such as enzyme, and non-enzymatic proteins. There were limited studies on the venoms and toxins of sea snake; hence, the aim of this systematic review was to investigate the toxinological dimensions of sea snakes.
In order to investigate of the toxins of sea snakes, the “Hydrophis schistosus toxin", "Hydrophis cyanocinctus toxin", " Hydrophis lapemoides toxin", "Hydrophis spiralis toxin", and "Lapemis curtus toxin " terms were searched separately, in "PubMed database", in 10/08/2016 which obtained 32, 9, 2, 2 and 4 papers, respectively. The "Hydrophis gracilis toxin" term had no any results. For the “Hydrophis gracilis" term, two studies were obtained. The first one related to the sea snakes phylogenetic characteristics and the second one shared with other search results and well-connected with the issue. Some papers were similar in different searches. Of these, those studies were selected that had direct relevance to the subject .
The main isolated toxins from different sea snakes venoms included three-finger toxin (3FTx (short chain neurotoxins isoforms: AAL54893, AAL54892, ABN54806; long chain neurotoxins isoforms: AAL54894, AAL54895, P68416 , ABN54805), pelamitoxin (P62388), phospholipase A2 (both the basic and acidic PLA2), two phospholipases A2 (PLA2-H1 and H2), cysteine-rich secretory protein (CRISP), snake venom Zn2+metalloproteinase (SVMP), L-amino acid oxidase (LAAO), 5′-nucleotidase, Hydrophitoxins a, b and c, Hydrophis ornatus a, Hydrophis lapemoides a, PDGF and α- neurotoxins of rSN311, rSN316 and rSN285. Each toxin and protein family presents a wide range of pharmacological activities. Some of these neurotoxins were linked to acetylcholine receptors in the neuromuscular junctions. These toxins showed protease (gelatinase and caseinase) activities, and/or they produce the myonecrosis and biochemical and histopathological changes.
There is scant variability in the venom composition in the same and different species of sea snakes. Our study revealed that there is a rather simple venom profile with an affinity towards a lethal mixture of high abundance of neurotoxins and PLA2s, and lower amounts of toxins such as CRISP, SVMP and LAAO.

Jellyfishes belong to the phylum Cnidarians with a wide range of size، from 22 centimeters to 2. 5 meters. Jellyfishes have a worldwide distribution comprising over nine thousands species that approximately، 100 species are dangerous for humans. The venoms of these organisms contain biomolecules with extensive activities which could be used as a source of novel drugs in the future. The PubMed data bank was searched for the term “Jellyfish”. A total of 1677 papers were found. These papers were divided into three categories: medical، biomedical and biotechnological fields. The medical category was further divided into three subcategories comprising systemic manifestations، cutaneous manifestations and treatments for the stings of jellyfishes. The biomedical category was further subdivided into genomics، proteomics، and biology of venoms، mechanisms of actions and products of biomedical significance. In this part of systematic review، the biomedical and biotechnological and biotechnological fields were evaluated. The genomics and proteomics of 24 species of jellyfishes had been studied in details. The mechanisms of actions of the venoms of 23 species were under investigations. The hematologic (hemolytic effects)، cardiotoxic، neurotoxic، dermonecrotic، immunologic and cytotoxic presentations for the venoms were reported. Similar clinical presentations could be produced by different species of jellyfishes with a vast of molecular action mechanisms. Bioactive molecules with cytotoxic، anticancer، antibacterial and antioxidant effects were isolated from the venoms. The venoms of jellyfishes have bioactive molecules that produce a variety of complex intracellular interactions. Hence، the studies on the venomics of jellyfishes and the mechanisms of actions of their venoms could progress the therapeutic interventions and promise novel marine drugs.

The hemotoxic and neurotoxic factors of snake venoms is the main responsible for necrosis and tissue sloughing. Envenomations are common in rural areas in all provinces of Iran caused by snake species which causes local swelling، ecchymosis and alterations in blood profile in case of hemotoxic venom. In this study some in vivo and in vitro properties (Hemorrhagic، edematogenic and coagualant) of Iranian Vipera lebetina venom in addition to neutralizing capacity of pepsin derived Razi Institute polyvalent antivenin were assayed. Escalating doses of Vipera lebetina venom dissolved in Normal saline (2. 5-50 µg/ml) were injected (100µl) subcutaneously to dorsal area of rats (n=3) to investigate mean hemorrhagic amount after 24 hours. Groups of three mice were injected subcutaneously in the right foodpad with various amounts of venom (10-150µg). The left foodpad received the same amount (100µl) ofnormal saline alone (negative control) to evaluate the edematogenic property of this venom. To determine the coagulant activity، various amounts of venom dissolved in normal saline (50µl) were added to human plasma (200µl) and coagulation time was measured. Razi Institute antivenom was used for neutralization of all three measured biological parameters. Mean hemorrhagic، procoagulant and edematous amounts (increasing 30% in hind paw edema) were 8. 5، 1. 1 and 70 microgram، respectively. Preincubation with polyvalent antibody (30 and 200 microliter) decreased hemorrhagic and procoagulant activity. Edematogenic property of this venom decreased significantly by incubation with antivenom (78% to 38% by incubation with 1000 microliter of polyvalent antivenom). Intra peritoneal injection of this remedy following envenomation had no effect in relieving symptoms. Myonecrotic effects were seen by intramuscular injection of Vipera lebetina venom in rats. Our study shows that Iranian antivenom could neutralize some in vivo and in vitro hazardous effects of envenomation by this snake like hemorrhagic، edematogenic and procoagulant properties that paves the way for separation and purification of multiple enzymes present in this venom to investigate the neutralizing capacity from Razi Institute polyvalent antivenom.