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Background. Scorpion stings may be life-threatening since their venoms are comprised of a wide range of toxins and other bioactive molecules, such as enzymes. At the same time, scorpion envenomation may increase matrix metalloproteases (MMPs) levels, which enhance proteolytic tissue destruction by venom. However, investigations on the impact of many scorpions' venoms, such as those of Leiurus macroctenus, on tissue proteolytic activity and MMP levels have not yet been conducted. Methods and Results. The present study aimed to examine the total proteolysis levels in various organs after Leiurus macroctenus envenomation and evaluate the metalloproteases and serine proteases' contributions to the total proteolytic activity. Changes in MMPs and TIMP-1 levels were tested as well. Envenomation led to a significant increase in proteolytic activity levels in all assessed organs, mostly in the heart (by 3.34 times) and lungs (by 2.25 times). Conclusions. Since EDTA presence showed a noticeable decrease in total proteolytic activity level, metalloproteases appeared to play a prominent role in total proteolytic activity. At the same time, MMPs and TIMP-1 levels were increased in all assessed organs, suggesting that Leiurus macroctenus envenomation causes systemic envenomation, which may induce multiple organ abnormalities, mostly because of the uncontrolled metalloprotease activity. [ABSTRACT FROM AUTHOR]

The accumulated data indicate that a high level of homocysteine may be a central pathogenetic factor of chronic obstructive pulmonary disease. In this study, we investigated the effect of hyperhomocysteinemia (HM) on protein homeostasis in the rat lungs. The level of proteins, peptides, total proteolytic activity, as well as protein-peptide composition, were evaluated. HM was induced by daily intragastric administration of DL-homocysteine thiolactone (100 mg·kg-1 of body weight) to albino non-linear male rats for 28 days. Twelve hours after the last administration, the rats were sacrificed and the lungs were harvested. Our findings showed that HM caused the disturbances in the protein homeostasis in the lungs that are manifested by a decrease in the level of proteins in the young and old animals and an increase in the level of peptides in the rats of all studied groups. We found a change in the protein composition in the lung of HM rats - a decrease in the level of proteins with a molecular weight of 50 kDa to 100 kDa simultaneously with an increase in the level of proteins with a molecular weight of less than 50 kDa. Despite the fact that the peptide profile was the same in both control animals and HM animals, the level of individual peptide fractions increased significantly in the rats with HM. Obtained data could contribute to explain, at least in part, the mechanisms involved in the pathogenesis of lung damage in HM. [ABSTRACT FROM AUTHOR]

Ischemic stroke is among the top diseases leading to mortality and disability in the world. The detailed investigation of the mechanisms underlying this pathology and especially mediating the tendency to relapse during the first year after stroke incident undoubtedly belongs to important tasks of modern medicine and biology. The current study aims to analyze the influence of IgG derived from the blood serum of ischemic stroke patients on some hemostasis factors. In total, 123 participants with IS, 62 with atherothrombotic ischemic stroke, 61 with cardioembolic ischemic stroke, and 57 subjects as control have been examined. The same patients have participated in the research a year after stroke. IgG from serum was isolated by affinity chromatography on protein A Sepharose column. The activity of key hemostasis factors under the influence of IgG was analyzed. Obtained results revealed that IgG of stroke patients but not healthy subjects caused the inhibition of the amidolytic activity of endogenously generated thrombin, protein C, factor Xa, and led to an increase in the degree of ADP-induced platelet aggregation. The reduction of clotting time in the test “Thrombin time” by IgG of patients at the acute phase of disease was also observed; IgG of healthy subjects mediated the opposite effect. In contrast to acute ischemic stroke IgG, IgG of patients one year after both atherothrombotic and cardioembolic ischemic stroke influenced only the activity of endogenously generated thrombin and factor Xa resulting in inhibition of their activities. It was also established that IgG of ischemic stroke patients, as well as healthy subjects, stimulated the secretion of tissue plasminogen activator by endotheliocytes. [ABSTRACT FROM AUTHOR]

Lichen-forming fungal proteins haw been seldom searched due to many difficulties in their extraction. Phenols, quinones, proteases, and other components released during cell disruption have been known to be the greatest challenges related to protein extraction from lichens. To overcome these problems and maintain good electrophorelic resolution and high protein concentration, an extraction buffer containing polyvinylpolypyrrolidone, ascorbic acid, Triton X-100, polyethylene glycol, proteinase, and oxidase inhibitors in sodium phosphate buffer was developed. This extraction buffer showed high efficiency for all lichen species tested in the study. [ABSTRACT FROM AUTHOR]

Background: The expansion of the territory of human habitation leads to inevitable interference in the natural range of distribution of one or another species of animals, some of which may be dangerous for human life. Scorpions-the Arachnida class and order Scorpiones-can be considered as such typical representatives. Scorpions of the Buthidae family pose a particular danger to humans. However, LD 50 has not yet been defined for many species of this family, in particular, new representatives of the genus Leiurus . Leiurus macroctenus is a newly described species of scorpion distributed in Oman, and the toxicity of its venom is still unknown. Estimating the LD 50 of the venom is the first and most important step in creating the antivenom and understanding the medical significance of the researched animal species. The purpose of this study was to determine the lethal dose (LD 100 ), the maximum tolerated dose (LD 0 ), and the average lethal dose (LD 50 ) in rats when using Leiurus macroctenus scorpion venom., Methods and Results: 15 sexually mature scorpions were used in the study, which were kept in the same conditions and milked by a common method (electric milking). For the study, 60 male rats were used, which were injected intramuscularly with 0.5 ml of venom solution with a gradual increase in the dose (5 groups, 10 rats in each), and 10 rats were injected intramuscularly with physiological solution as control group. LD calculations were done using probit analysis method in the modification of the method by V.B. Prozorovsky. The LD 0 of Leiurus macroctenus scorpion venom under the conditions of intramuscular injection was 0.02 mg/kg, LD 100 was 0.13 mg/kg, and LD 50 was 0.08 ± 0.01 mg/kg., Conclusions: The analysis of scientific publications and other sources of information gives reason to believe that Leiurus macroctenus has one of the highest values of LD 50 not only among scorpions but also among all arthropods in the world. All these point to the significant clinical importance of this species of scorpion and require further research that will concern the toxic effect of its venom on various organ systems. Determining the LD50 of the venom for new scorpion species is crucial for creating effective antivenoms and understanding the medical implications of envenomation by this species., Competing Interests: The authors have no conflicts of interest to declare., (Copyright © 2024 Valery Gunas et al.)