Analysis of Relationship between Microwave Magnetic Properties and Magnetic Structure of Permalloy Films.

Changes in the microwave permeability of permalloy films with an increase in the film thickness are studied. Measurement data on the evolution of microwave permeability with film thickness are analyzed in the framework of a model for the film with a regular stripe domain structure and out-of-plane magnetic anisotropy. A correlation between the microwave magnetic properties and magnetic structure of permalloy films is established.

The Potassium Channel Blocker β-Bungarotoxin from the Krait Venom Manifests Antiprotozoal Activity.

Protozoal infections are a world-wide problem. The toxicity and somewhat low effectiveness of the existing drugs require the search for new ways of protozoa suppression. Snake venom contains structurally diverse components manifesting antiprotozoal activity; for example, those in cobra venom are cytotoxins.

The Size Dependence of Microwave Permeability of Hollow Iron Particles.

Hollow ferromagnetic powders of iron were obtained by means of ultrasonic spray pyrolysis. A variation in the conditions of the synthesis allows for the adjustment of the mean size of the hollow iron particles. Iron powders were obtained by this technique, starting from the aqueous solution of iron nitrate of two different concentrations: 10 and 20 wt.

Snake venom phospholipase As exhibit strong virucidal activity against SARS-CoV-2 and inhibit the viral spike glycoprotein interaction with ACE2.

The COVID-19 pandemic caused by SARS-CoV-2 requires new treatments both to alleviate the symptoms and to prevent the spread of this disease. Previous studies demonstrated good antiviral and virucidal activity of phospholipase As (PLAs) from snake venoms against viruses from different families but there was no data for coronaviruses. Here we show that PLAs from snake venoms protect Vero E6 cells against SARS-CoV-2 cytopathic effects.

Deposition of a SiO Shell of Variable Thickness and Chemical Composition to Carbonyl Iron: Synthesis and Microwave Measurements.

Protective SiO coating deposited to iron microparticles is highly demanded both for the chemical and magnetic performance of the latter. Hydrolysis of tetraethoxysilane is the crucial method for SiO deposition from a solution. The capabilities of this technique have not been thoroughly studied yet.

α-Conotoxins and α-Cobratoxin Promote, while Lipoxygenase and Cyclooxygenase Inhibitors Suppress the Proliferation of Glioma C6 Cells.

Among the brain tumors, glioma is the most common. In general, different biochemical mechanisms, involving nicotinic acetylcholine receptors (nAChRs) and the arachidonic acid cascade are involved in oncogenesis. Although the engagement of the latter in survival and proliferation of rat C6 glioma has been shown, there are practically no data about the presence and the role of nAChRs in C6 cells.

Screening Snake Venoms for Toxicity to Revealed Anti-Protozoan Activity of Cobra Cytotoxins.

Snake venoms possess lethal activities against different organisms, ranging from bacteria to higher vertebrates. Several venoms were shown to be active against protozoa, however, data about the anti-protozoan activity of cobra and viper venoms are very scarce. We tested the effects of venoms from several snake species on the ciliate .

α-Conotoxins Enhance both the In Vivo Suppression of Ehrlich carcinoma Growth and In Vitro Reduction in Cell Viability Elicited by Cyclooxygenase and Lipoxygenase Inhibitors.

Several biochemical mechanisms, including the arachidonic acid cascade and activation of nicotinic acetylcholine receptors (nAChRs), are involved in increased tumor survival. Combined application of inhibitors acting on these two pathways may result in a more pronounced antitumor effect. Here, we show that baicalein (selective 12-lipoxygenase inhibitor), nordihydroguaiaretic acid (non-selective lipoxygenase inhibitor), and indomethacin (non-selective cyclooxygenase inhibitor) are cytotoxic to Ehrlich carcinoma cells in vitro.

Anticoagulant Activity of Low-Molecular Weight Compounds from Heterometrus laoticus Scorpion Venom.

Scorpion venoms are complex polypeptide mixtures, the ion channel blockers and antimicrobial peptides being the best studied components. The coagulopathic properties of scorpion venoms are poorly studied and the data about substances exhibiting these properties are very limited. During research on the scorpion venom, we have isolated low-molecular compounds with anticoagulant activity.

Cobra Venom Factor and Ketoprofen Abolish the Antitumor Effect of Nerve Growth Factor from Cobra Venom.

We showed recently that nerve growth factor (NGF) from cobra venom inhibited the growth of Ehrlich ascites carcinoma (EAC) inoculated subcutaneously in mice. Here, we studied the influence of anti-complementary cobra venom factor (CVF) and the non-steroidal anti-inflammatory drug ketoprofen on the antitumor NGF effect, as well as on NGF-induced changes in EAC histological patterns, the activity of lactate and succinate dehydrogenases in tumor cells and the serum level of some cytokines. NGF, CVF and ketoprofen reduced the tumor volume by approximately 72%, 68% and 30%, respectively.

Inhibition of nicotinic acetylcholine receptors, a novel facet in the pleiotropic activities of snake venom phospholipases A2.

Phospholipases A2 represent the most abundant family of snake venom proteins. They manifest an array of biological activities, which is constantly expanding. We have recently shown that a protein bitanarin, isolated from the venom of the puff adder Bitis arietans and possessing high phospholipolytic activity, interacts with different types of nicotinic acetylcholine receptors and with the acetylcholine-binding protein.

Nerve growth factor from cobra venom inhibits the growth of Ehrlich tumor in mice.

The effects of nerve growth factor (NGF) from cobra venom (cvNGF) on growth of Ehrlich ascites carcinoma (EAC) cells inoculated subcutaneously in mice have been studied. The carcinoma growth slows down, but does not stop, during a course of cvNGF injections and restores after the course has been discontinued. The maximal anti-tumor effect has been observed at a dose of 8 nmoles cvNGF/kg body weight.

Dimeric α-cobratoxin X-ray structure: localization of intermolecular disulfides and possible mode of binding to nicotinic acetylcholine receptors.

In Naja kaouthia cobra venom, we have earlier discovered a covalent dimeric form of α-cobratoxin (αCT-αCT) with two intermolecular disulfides, but we could not determine their positions. Here, we report the αCT-αCT crystal structure at 1.94 Å where intermolecular disulfides are identified between Cys(3) in one protomer and Cys(20) of the second, and vice versa.

An unusual phospholipase A₂ from puff adder Bitis arietans venom--a novel blocker of nicotinic acetylcholine receptors.

The venoms of snakes from Viperidae family mainly influence the function of various blood components. However, the published data indicate that these venoms contain also neuroactive components, the most studied being neurotoxic phospholipases A₂ (PLA₂s). Earlier we have shown (Gorbacheva et al.

Interaction of alpha-conotoxin ImII and its analogs with nicotinic receptors and acetylcholine-binding proteins: additional binding sites on Torpedo receptor.

alpha-Conotoxins interact with nicotinic acetylcholine receptors (nAChRs) and acetylcholine-binding proteins (AChBPs) at the sites for agonists/competitive antagonists. alpha-Conotoxins blocking muscle-type or alpha7 nAChRs compete with alpha-bungarotoxin. However, alpha-conotoxin ImII, a close homolog of the alpha7 nAChR-targeting alpha-conotoxin ImI, blocked alpha7 and muscle nAChRs without displacing alpha-bungarotoxin (Ellison et al.

A new type of thrombin inhibitor, noncytotoxic phospholipase A2, from the Naja haje cobra venom.

Thrombin is a key enzyme in the blood coagulation cascade and is also involved in carcinogenesis; therefore, its inhibitors are of fundamental and clinical importance. Snake venoms are widely used as sources of proteins that affect blood coagulation. We have isolated a new protein, called TI-Nh, from the Naja haje cobra venom.

Cysteine-rich venom proteins from the snakes of Viperinae subfamily - molecular cloning and phylogenetic relationship.

Cysteine-rich proteins found in animal venoms (CRISP-Vs) are members of a large family of cysteine-rich secretory proteins (CRISPs). CRISP-Vs acting on different ion channels were found in venoms or mRNA (cDNA) encoding CRISP-Vs were cloned from snakes of three main families (Elapidae, Colubridae and Viperidae). About thirty snake CRISP-Vs were sequenced so far, however no complete sequence for CRISP-V from Viperinae subfamily was reported.

Naturally occurring disulfide-bound dimers of three-fingered toxins: a paradigm for biological activity diversification.

Disulfide-bound dimers of three-fingered toxins have been discovered in the Naja kaouthia cobra venom; that is, the homodimer of alpha-cobratoxin (a long-chain alpha-neurotoxin) and heterodimers formed by alpha-cobratoxin with different cytotoxins. According to circular dichroism measurements, toxins in dimers retain in general their three-fingered folding. The functionally important disulfide 26-30 in polypeptide loop II of alpha-cobratoxin moiety remains intact in both types of dimers.

Non-lethal polypeptide components in cobra venom.

Snakes from several genera (mostly from Naja genus) belonging to the Elapidae family are usually named cobras. The effect of cobra bites is mainly neurotoxic. This is explained by the presence of highly potent alpha-neurotoxin in their venoms.

Toxicity of venoms from vipers of Pelias group to crickets Gryllus assimilis and its relation to snake entomophagy.

The existing data indicate that snake venom is most toxic towards the natural vertebrate preys. Several species of snake include arthropods in their food. However, there is no available data on the toxicity of venom from entomophagous snakes towards their prey.

Naja melanoleuca cobra venom contains two forms of complement-depleting factor (CVF).

Two forms of complement-depleting cobra venom factor (CVFm1 and CVFm2), possessing molecular masses of 142.6 kDa (CVFm1) and 143.1 kDa (CVFm2), according to MALDI mass-spectrometry, were isolated from the Naja melanoleuca cobra venom.

Oxiagin from the Naja oxiana cobra venom is the first reprolysin inhibiting the classical pathway of complement.

A basic glycoprotein oxiagin with molecular mass of 49.8 kDa was isolated from the venom of Central Asian cobra Naja oxiana. Partial amino acid sequence determination has shown that oxiagin belongs to reprolysins, a subfamily of animal metalloproteinases possessing a characteristic multidomain structure.

Cobra venom contains a pool of cysteine-rich secretory proteins.

A large family of cysteine-rich secretory proteins (CRISPs) includes proteins of different origin, the function of the majority of CRISPs being unknown. For CRISPs isolated from snake venom, two types of activities were found: two proteins blocked cyclic nucleotide-gated ion channels, several others blocked potassium-stimulated smooth muscle contraction. Thus, snake CRISPs represent potentially valuable tools for studies of ion channels, which makes promising a search for new CRISPs.

The first representative of glycosylated three-fingered toxins. Cytotoxin from the Naja kaouthia cobra venom.

There are different glycosylated proteins in snake venoms, but no glycosylated representatives of a large family of three-fingered toxins have previously been detected. A new glycoprotein was isolated from the venom of the Thai cobra Naja kaouthia. MALDI MS of the glycoprotein contained an array of peaks in the range from approximately 8900 to approximately 9400 Da indicating its microheterogeneity.

Toxicity of cobra venom components to cockroach Gromphadorhina portentosa.

The toxicity of the Thailand and Middle-Asian cobra venoms as well as of their isolated components (neurotoxins, cytotoxins, phospholipases and some others) for cockroach Gromphadorhina portentosa was studied. It was found that, as compared to mammals, cockroaches are more resistant to cobra venoms and their components. At intraabdominal injection the most toxic for cockroaches were cytotoxins (LD(50) 1.