Action Of Toxin Research Articles

Type I toxin-antitoxin systems in bacteria: from regulation to biological functions.

Toxin-antitoxin systems are ubiquitous in the prokaryotic world and widely distributed among chromosomes and mobile genetic elements. Several different toxin-antitoxin system types exist, but what they all have in common is that toxin activity is prevented by the cognate antitoxin. In type I toxin-antitoxin systems, toxin production is controlled by an RNA antitoxin and by structural features inherent to the toxin messenger RNA. Most type I toxins are small membrane proteins that display a variety of cellular effects. While originally discovered as modules that stabilize plasmids, chromosomal type I toxin-antitoxin systems may also stabilize prophages, or serve important functions upon certain stress conditions and contribute to population-wide survival strategies. Here, we will describe the intricate RNA-based regulation of type I toxin-antitoxin systems and discuss their potential biological functions.

A versatile immunoassay based on functionalized nanoparticles for botulinum neurotoxin detection and sensor development

Botulinum neurotoxins (BoNTs) serotypes A and B are the two most common of the four BoNTs that cause the high mortality botulism disease in individuals consuming contaminated foods. The gold standard assay for BoNT detection is the live mouse bioassay, which has several major disadvantages, including tedious procedures and animal sacrifice requirements. In this study, we developed an immuno-based assay using magnetic streptavidin nanoparticles (mSNP) functionalized with specific synthetic biotinylated, 6xHis-tagged peptide substrates (Peptides A, PA and B, PB) designed for BoNT/A and BoNT/B proteolytic reactions, respectively. In the presence of active toxins that possess endopeptidase activity, upon cleavage, the released fragments with His-tag were dotted on a blotting membrane, ultimately producing color signals after incubation with anti-His antibody, alkaline phosphatase (AP)-conjugated antibody, and then AP substrates. The results showed that the efficiency of peptide-mSNP complex formation reached up to 81%, and the dot blot immunoassay allowed peptide detection from 10 ng of His-tagged peptides. Preliminary testing with the extracellular extracts from the isolated Clostridium botulinum strains indicated that the botulinum toxin in the 2020 botulism outbreak in Vietnam belonged to serotype A, the most potent BoNT. The established assay could be applied to construct a portable biosensor for BoNT detection and a high throughput device to screen potential BoNT inhibitors for drug development.

Characterization of the individual domains of the Bacillus thuringiensis Cry2Aa implicates Domain I as a possible binding site to Helicoverpa armigera

Bacillus thuringiensis (Bt) Cry2Aa is a member of the Cry pore-forming, 3-domain, toxin family with activity against both lepidopteran and dipteran insects. Although domains II and III of the Cry toxins are believed to represent the primary specificity determinant through specific binding to cell receptors, it has been proposed that the pore-forming domain I of Cry2Aa also has such a role. Thus, a greater understanding of the functions of Cry2Aa’s different domains could potentially be helpful in the rational design of improved toxins.In this work, cry2Aa and its domain fragments (DI, DII, DIII, DI-II and DII-DIII) were subcloned into the vector pGEX-6P-1 and expressed in Escherichia coli. Each protein was recognized by anti-Cry2Aa antibodies and, except for the DII fragment, could block binding of the antibody to Cry2Aa. Cry2Aa and its DI and DI-II fragments bound to brush border membrane vesicles (BBMV) from H. armigera and also to a ca 150 kDa BBMV protein on a far western (ligand) blot. In contrast the DII, DIII and DII-III fragments bound to neither of these. None of the fragments were stable in H. armigera gut juice nor showed any toxicity towards this insect. Our results indicate that contrary to the general model of Cry toxin activity domain I plays a role in the binding of the toxin to the insect midgut.

Overview of Bacterial Protein Toxins from Pathogenic Bacteria: Mode of Action and Insights into Evolution.

Bacterial protein toxins are secreted by certain bacteria and are responsible for mild to severe diseases in humans and animals. They are among the most potent molecules known, which are active at very low concentrations. Bacterial protein toxins exhibit a wide diversity based on size, structure, and mode of action. Upon recognition of a cell surface receptor (protein, glycoprotein, and glycolipid), they are active either at the cell surface (signal transduction, membrane damage by pore formation, or hydrolysis of membrane compound(s)) or intracellularly. Various bacterial protein toxins have the ability to enter cells, most often using an endocytosis mechanism, and to deliver the effector domain into the cytosol, where it interacts with an intracellular target(s). According to the nature of the intracellular target(s) and type of modification, various cellular effects are induced (cell death, homeostasis modification, cytoskeleton alteration, blockade of exocytosis, etc.). The various modes of action of bacterial protein toxins are illustrated with representative examples. Insights in toxin evolution are discussed.

Spatio-temporal brain invasion pattern of Streptococcus pneumoniae and dynamic changes in the cellular environment in bacteremia-derived meningitis

Streptococcus pneumoniae (the pneumococcus) is the major cause of bacterial meningitis globally, and pneumococcal meningitis is associated with increased risk of long-term neurological sequelae. These include several sensorimotor functions that are controlled by specific brain regions which, during bacterial meningitis, are damaged by a neuroinflammatory response and the deleterious action of bacterial toxins in the brain. However, little is known about the invasion pattern of the pneumococcus into the brain. Using a bacteremia-derived meningitis mouse model, we combined 3D whole brain imaging with brain microdissection to show that all brain regions were equally affected during disease progression, with the presence of pneumococci closely associated to the microvasculature. In the hippocampus, the invasion provoked microglial activation, while the neurogenic niche showed increased proliferation and migration of neuroblasts. Our results indicate that, even before the outbreak of symptoms, the bacterial load throughout the brain is high and causes neuroinflammation and cell death, a pathological scenario which ultimately leads to a failing regeneration of new neurons.

An in vitro assay for toxicity testing of Clostridium perfringens type C β-toxin.

Veterinary vaccines against Clostridium perfringens type C need to be tested for absence of toxicity, as mandated by pharmacopoeias worldwide. This toxicity testing is required at multiple manufacturing steps and relies on outdated mouse tests that involve severe animal suffering. Clostridium perfringens type C produces several toxins of which the β-toxin is the primary component responsible for causing disease. Here, we describe the successful development of a new cell-based in vitro assay that can address the specific toxicity of the β-toxin. Development of the cell-based assay followed the principle of in vitro testing developed for Cl. septicum vaccines, which is based on Vero cells. We screened four cell lines and selected the THP-1 cell line, which was shown to be the most specific and sensitive for β-toxin activity, in combination with a commercially available method to determine cell viability (MTS assay) as a readout. The current animal test is estimated to detect 100 - 1000-fold dilutions of the Cl. perfringens type C non-inactivated antigen. When tested with an active Cl. perfringens type C antigen preparation, derived from a commercial vaccine manufacturing process, our THP-1 cell-based assay was able to detect toxin activity from undiluted to over 10000-fold dilution, showing a linear range between approximately 1000- and 10000-fold dilutions. Assay specificity for the β-toxin was confirmed with neutralizing antibodies and lack of reaction to Cl. perfringens culture medium. In addition, assay parameters demonstrated good repeatability. Here, we have shown proof of concept for a THP-1 cell-based assay for toxicity testing of veterinary Cl. perfringens type C vaccines that is suitable for all vaccine production steps. This result represents a significant step towards the replacement of animal-based toxicity testing of this veterinary clostridial antigen. As a next step, assessment of the assay's sensitivity and repeatability and validation of the method will have to be performed in a commercial manufacturing context in order to formally implement the assay in vaccine quality control.

Variable gut pH as a potential mechanism of tolerance to Bacillus thuringiensis subsp. israelensis toxins in the biting midge Culicoides sonorensis.

Toxins of Bacillus thuringiensis subsp. israelensis (Bti) are safer alternatives for controlling dipteran pests such as black flies and mosquitoes. The biting midge Culicoides sonorensis (Diptera: Ceratopogonidae) is an important pest of livestock in much of the United States and larval midges utilize semi-aquatic habitats which are permissive for Bti product application. Reports suggest that Bti products are ineffective at killing biting midges despite their taxonomic relation to black flies and mosquitoes. Here, we investigate the toxicity of a Bti-based commercial insecticide and its active ingredient in larval Culicoides sonorensis. A suspected mechanism of Bti tolerance is an acidic larval gut, and we used a pH indicator dye to examine larval Culicoides sonorensis gut pH after exposure to Bti. The lethal concentration to kill 90% (LC90) of larvae ofthe commercial product (386 mg/L) was determined to be almost 10 000 times more than that of some mosquito species, and no concentration of active ingredient tested achieved 50% larval mortality. The larval gut was found to be more acidic after exposure to Bti which inhibits Bti toxin activity. By comparison, 100% mortality was achieved in larval Aedes aegypti at the product's label rate for this species and mosquito larvae had alkaline guts regardless of treatment. Altering the larval rearing water to alkaline conditions enhanced Bti efficacy when using the active ingredient. We conclude that Bti is not practical for larval Culicoides sonorensis control at the same rates as mosquitos but show that alterations or additives to the environment could make the products more effective. © 2024 Society of Chemical Industry.

Mitochondrial injury induced by a Salmonella genotoxin triggers the proinflammatory senescence-associated secretory phenotype

Bacterial genotoxins damage host cells by targeting their chromosomal DNA. In the present study, we demonstrate that a genotoxin of Salmonella Typhi, typhoid toxin, triggers the senescence-associated secretory phenotype (SASP) by damaging mitochondrial DNA. The actions of typhoid toxin disrupt mitochondrial DNA integrity, leading to mitochondrial dysfunction and disturbance of redox homeostasis. Consequently, it facilitates the release of damaged mitochondrial DNA into the cytosol, activating type I interferon via the cGAS-STING pathway. We also reveal that the GCN2-mediated integrated stress response plays a role in the upregulation of inflammatory components depending on the STING signaling axis. These SASP factors can propagate the senescence effect on T cells, leading to senescence in these cells. These findings provide insights into how a bacterial genotoxin targets mitochondria to trigger a proinflammatory SASP, highlighting a potential therapeutic target for an anti-toxin intervention.

Identification of Genes Encoded Toxin-Antitoxin System in Mycobacterium Tuberculosis Strains from Clinical Sample.

The toxin-antitoxin system is a genetic element that is highly present in Mycobacterium tuberculosis (MTB), the causative agent of tuberculosis. The toxin-antitoxin sys-tem comprises toxin protein and antitoxin protein or non-encoded RNA interacting with each other and inhibiting toxin activity. M. Tuberculosis has more classes of TA loci than non-tubercle bacilli and other microbes, including VapBC, HigBA, MazEF, ParDE, RelBE, MbcTA, PemIK, DarTG, MenTA, one tripartite type II TAC chaperone system, and hypothetical proteins. The study aims to demonstrate the genes encoded toxin-antitoxin system in mycobacterium tuberculosis strains from clinical samples. The pulmonary and extra-pulmonary tuberculosis clinical samples were collected, and smear microscopy (Ziehl-Neelsen staining) was performed for the detection of high bacilli (3+) count, followed by nucleic acid amplification assay. Bacterial culture and growth assay, genomic DNA extraction, and polymerase chain reaction were also carried out. The positive PTB and EPTB samples were determined by 3+ in microscopy smear [20], and the total count of tubercle bacilli determined by NAAT assay was 8.0×1005 in sputum and 1.3×1004 CFU/ml in tissue abscess. Moreover, the genomic DNA was extracted from culture, and the amplification of Rv1044 and Rv1045 genes in 624 and 412 base pairs (between 600-700 and 400-500 in ladder), respectively, in the H37Rv and clinical samples was observed. It has been found that Rv1044 and Rv1045 are hypothetical proteins with 624 and 882 base pairs belonging to the AbiEi/AbiEii family of toxin-antitoxin loci. Moreover, the signifi-cant identification of TA-encoded loci genes may allow for the investigation of multidrug-resistant and extensively drug-resistant tuberculosis.

Synthesis of biologically active Shiga toxins in cell-free systems

Shiga toxins (Stx) produced by pathogenic bacteria can cause mild to severe diseases in humans. Thus, the analysis of such toxins is of utmost importance. As an AB5 toxin, Stx consist of a catalytic A-subunit acting as a ribosome-inactivating protein (RIP) and a B-pentamer binding domain. In this study we synthesized the subunits and holotoxins from Stx and Stx2a using different cell-free systems, namely an E. coli- and CHO-based cell-free protein synthesis (CFPS) system. The functional activity of the protein toxins was analyzed in two ways. First, activity of the A-subunits was assessed using an in vitro protein inhibition assay. StxA produced in an E. coli cell-free system showed significant RIP activity at concentrations of 0.02 nM, whereas toxins synthesized in a CHO cell-free system revealed significant activity at concentrations of 0.2 nM. Cell-free synthesized StxA2a was compared to StxA2a expressed in E. coli cells. Cell-based StxA2a had to be added at concentrations of 20 to 200 nM to yield a significant RIP activity. Furthermore, holotoxin analysis on cultured HeLa cells using an O-propargyl-puromycin assay showed significant protein translation reduction at concentrations of 10 nM and 5 nM for cell-free synthesized toxins derived from E. coli and CHO systems, respectively. Overall, these results show that Stx can be synthesized using different cell-free systems while remaining functionally active. In addition, we were able to use CFPS to assess the activity of different Stx variants which can further be used for RIPs in general.

Membrane Interaction Characteristics of the RTX Toxins and the Cholesterol-Dependence of Their Cytolytic/Cytotoxic Activity.

RTX toxins are important virulence factors produced by a wide range of Gram-negative bacteria. They are secreted as water-soluble proteins that are able to bind to the host cell membrane and insert hydrophobic segments into the lipid bilayer that ultimately contribute to the formation of transmembrane pores. Ion diffusion through these pores leads then to cytotoxic and cytolytic effects on the hosts. Several reports have evidenced that the binding of several RTX toxins to the target cell membrane may take place through a high-affinity interaction with integrins of the β2 family that is highly expressed in immune cells of the myeloid lineage. However, at higher toxin doses, cytotoxicity by most RTX toxins has been observed also on β2-deficient cells in which toxin binding to the cell membrane has been proposed to occur through interaction with glycans of glycosylated lipids or proteins present in the membrane. More recently, cumulative pieces of evidence show that membrane cholesterol is essential for the mechanism of action of several RTX toxins. Here, we summarize the most important aspects of the RTX toxin interaction with the target cell membrane, including the cholesterol dependence, the recent identification in the sequences of several RTX toxins of linear motifs coined as the Cholesterol Recognition/interaction Amino acid Consensus (CRAC), and the reverse or mirror CARC motif, which is involved in the toxin-cholesterol interaction.

Clostridium perfringens-induced massive hemolysis treatment with blood purification to target toxins: a case report.

Clostridium perfringens can rarely cause severe systemic infections, usually from an abdominal source, associated with massive hemolysis, which is usually fatal. Hemolytic anemia and acute renal injury resulting from toxin action are critical for the development of multiple organ dysfunction syndrome (MODs), making this condition a real emergency, requiring multispecialty skills and aggressive multimodal therapies. We herein describe a case of septic shock from acute cholecystitis with massive hemolysis caused by C. perfringens in a 55year-old man that was successfully treated with early blood purification and continuous renal replacement therapy (CRRT) along with antibiotic therapy and surgery. The effect of the enormous amount of toxins produced by Clostridium which elicit a strong cytokine response and the damage caused by the hemolysis products are the main pathogenetic mechanisms of this rare but lethal clinical entity. The main goal of treatment is to remove toxins from plasma, block toxin action, and further production by achieving bacterial killing with antimicrobial agents and controlling the infectious focus, remove waste products and prevent or limit multiorgan damage. Blood purification techniques play an important role due to a strong pathophysiological rationale, as they can remove toxins and cytokines as well as cell-free products from plasma and also replace renal function. Although this condition is rare and robust data are lacking, blood purification techniques for C. perfringens-induced massive hemolysis are promising and should be further explored.

Transcriptome analysis reveals the inhibitory mechanism of phloretin on virulence expression of Staphylococcus aureus and its application in cooked chicken

Staphylococcus aureus (S. aureus) enterotoxins have aroused great concern to food safety owing to its increased risk of food poisoning. The current research aimed to investigate the anti-virulence mechanisms of phloretin against S. aureus in terms of toxin activity and gene expression. The results indicated that phloretin could effectively inhibit the production of hemolysins and enterotoxins, and its anti-virulence effect was exerted in a concentration-dependent manner. Transcriptome results indicated that phloretin could downregulate the transcription level of majority virulence factors related genes (68 %) of S. aureus, including the quorum sensing-related genes (agrB, agrC, agrA, sspA, splF, splD and others) and bacterial secretion system-related genes (secDF, secY2, and yidC). In addition, it was speculated that phloretin was most likely to bind to the AgrA DNA binding domain, thereby affecting the expression of downstream virulence genes (hla, seb, spa, rot, geh, etc) based on molecular docking. Finally, the application in cooked chicken indicated that phloretin could effectively decrease the content of enterotoxins and improve the storage quality of cooked chicken. These findings not only evidenced the feasible anti-virulence activity of phloretin, but also provided a new strategy to prevent S. aureus food poisoning in cooked meat preservation.

Exploring the Pathogenesis of Clostridium difficile Infection Based on Weighted Gene Co-expression Network Analysis

Clostridioides difficile, a Gram-positive, spore-forming, anaerobic bacterium, is a leading cause of antibiotic-associated diarrhea and colitis. Its infections, often linked to antibiotic use in healthcare settings, range from mild diarrhea to pseudomembranous colitis. This study explores the pathogenic and toxin action mechanisms of Clostridioides difficile, particularly its toxins TcdA and TcdB, which disrupt host cells through glycosyltransferase activity, affecting cell structure and intestinal integrity, while also triggering inflammation and immune responses. Treatment strategies for Clostridioides difficile infection continue to evolve, encompassing antibiotics, microbiota replacement, monoclonal antibodies, and emerging therapies. The study employs Weighted Gene Co-expression Network Analysis (WGCNA)to analyze the GSE29008 dataset, categorizing samples into normal, toxin A, and toxin B groups. Notably, the 'midnightblue' module shows a strong positive correlation with toxin B, indicating its significant role in severe inflammation and tissue damage, emphasizing the importance of understanding the toxin action mechanisms for developing effective treatments and public health policies.

Presence of elsinochrome and other putative effectors in select genomes of the plant pathogen Elsinoë spp. based on in silico analysis

The genus Elsinoë comprises obligate fungal pathogens known to cause scab disease in various crops, including mango, peanut, and sweet potato. In other fungal plant pathogens, secreted proteins or effectors and other secondary metabolites have been characterized as being involved mainly in stimulating host responses, such as the eventual manifestation of distinct symptoms on specific crops or as indications of host specialization. In line with this, variability in the genes conferring for the corresponding effector proteins and other secondary metabolites has also been identified between species of the same fungal genus and has helped in elucidating phylogenetic relationships and in determining host preferences. Available draft genomes of six plant pathogenic Elsinoë spp. retrieved from the NCBI were utilized in this study to assess their variations in terms of putative effectors and other secondary metabolites, along with in silico descriptions of their potential biological function and evolutionary relationships. Genome prediction revealed, on average, 3000 cytoplasmic effectors and approximately 280 apoplastic effectors across the species. Pathogenicity and virulence effectors such as melanin and elsinochrome were specifically detected in all the Elsinoë spp. genomes, with considerable variation between species. Ontology analysis revealed putative genes related to toxin activity, detoxification, and carbohydrate binding in Elsinoë. Furthermore, phylogenetic analysis of the internal transcribed spacer (ITS) and elsinochrome biosynthetic genes revealed clustering of Elsinoë spp. based on the host. These findings suggest that the disease status of different plant hosts infected by different Elsinoë spp. varies.

Equine grass sickness is associated with major abnormalities in the ultrastructure of skeletal neuromuscular junctions.

Equine grass sickness (EGS) is a frequently fatal multisystem neuropathy of equids. The aetiology is unknown; proposed causes include toxicoinfection with Clostridium botulinum and a mycotoxicosis. The effect of EGS on the organisation and structural integrity of the skeletal neuromuscular junction (NMJ), the target of botulinum neurotoxins (BoNTs), is unknown. To compare the organisation and structural integrity of skeletal NMJs from EGS horses, control horses and one horse with a presumptive diagnosis of botulism. Blinded, retrospective case control. NMJs in samples of diaphragm or intercostal muscle from six EGS horses, three control horses and one equine botulism case were compared using electron microscopy, morphometry and confocal light microscopy. A significantly higher percentage of EGS NMJs had abnormal morphology (EGS 72.2%, 95% CI 55.6-84.4; Controls 6.9%, 1.7-23.8; OR 35.1, 8.47-244.8; p < 0.001). EGS NMJs had a significantly lower mean volume fraction occupied by synaptic vesicles (SVs) (EGS 18.7%, 12.6-28.0; Controls 36.3%, 20.8-63.4; p = 0.024). EGS NMJs had evidence of accelerated SV exocytosis and SV depletion, accumulation of neurofilament-like material in terminal boutons and/or bouton degeneration. NMJs from the botulism horse had dense packing of SVs towards the presynaptic membrane active zone, consistent with BoNT intoxication, but had absence of the abnormalities identified in EGS NMJs. Group sizes were limited by difficulties obtaining suitably processed samples. Ages of control and EGS horses differed. Botulism was diagnosed based on clinical and post mortem findings. EGS is associated with major changes in skeletal NMJ ultrastructure that are inconsistent with the effects of BoNTs. SV depletion may reflect increased exocytosis coupled with reduced repopulation of SVs via anterograde axonal transport and endocytosis, consistent with the action of an excitatory presynaptic toxin and/or neurotransmitter reuptake inhibitor. Skeletal NMJs represent a previously unrecognised target for the toxin that causes EGS.

Engineering of Bacillus thuringiensis Cry2Ab toxin for improved insecticidal activity

Bacillus thuringiensis Cry2Ab toxin was a widely used bioinsecticide to control lepidopteran pests all over the world. In the present study, engineering of Bacillus thuringiensis Cry2Ab toxin was performed for improved insecticidal activity using site-specific saturation mutation. Variants L183I were screened with lower LC50 (0.129 µg/cm2) against P. xylostella when compared to wild-type Cry2Ab (0.267 µg/cm2). To investigate the molecular mechanism behind the enhanced activity of variant L183I, the activation, oligomerization and pore-formation activities of L183I were evaluated, using wild-type Cry2Ab as a control. The results demonstrated that the proteolytic activation of L183I was the same as that of wild-type Cry2Ab. However, variant L183I displayed higher oligomerization and pore-formation activities, which was consistence with its increased insecticidal activity. The current study demonstrated that the insecticidal activity of Cry2Ab toxin could be assessed using oligomerization and pore-formation activities, and the screened variant L183I with improved activity might contribute to Cry2Ab toxin’s future application.

VapC10 toxin of the legume symbiont Sinorhizobium meliloti targets tRNASer and controls intracellular lifestyle.

The soil bacterium Sinorhizobium meliloti can establish a nitrogen-fixing symbiosis with the model legume Medicago truncatula. The rhizobia induce the formation of a specialized root organ called nodule, where they differentiate into bacteroids and reduce atmospheric nitrogen into ammonia. Little is known on the mechanisms involved in nodule senescence onset and in bacteroid survival inside the infected plant cells. Although toxin-antitoxin (TA) systems have been shown to promote intracellular survival within host cells in human pathogenic bacteria, their role in symbiotic bacteria was rarely investigated. S. meliloti encodes several TA systems, mainly of the VapBC family. Here we present the functional characterization, through a multidisciplinary approach, of the VapBC10 TA system of S. meliloti. Following a mapping by overexpression of an RNase in Escherichia coli (MORE) RNA-seq analysis, we demonstrated that the VapC10 toxin is an RNase that cleaves the anticodon loop of two tRNASer. Thereafter, a bioinformatics approach was used to predict VapC10 targets in bacteroids. This analysis suggests that toxin activation triggers a specific proteome reprogramming that could limit nitrogen fixation capability and viability of bacteroids. Accordingly, a vapC10 mutant induces a delayed senescence in nodules, associated to an enhanced bacteroid survival. VapBC10 TA system could contribute to S. meliloti adaptation to symbiotic lifestyle, in response to plant nitrogen status.

STEP: profiling cellular-specific targets and pathways of bioactive small molecules in tissues via integrating single-cell transcriptomics and chemoproteomics.

Identifying the cellular targets of bioactive small molecules within tissues has been a major concern in drug discovery and chemical biology research. Compared to cell line models, tissues consist of multiple cell types and complicated microenvironments. Therefore, elucidating the distribution and heterogeneity of targets across various cells in tissues would enhance the mechanistic understanding of drug or toxin action in real-life scenarios. Here, we present a novel multi-omics integration pipeline called Single-cell TargEt Profiling (STEP) that enables the global profiling of protein targets in mammalian tissues with single-cell resolution. This pipeline integrates single-cell transcriptome datasets with tissue-level protein target profiling using chemoproteomics. Taking well-established classic drugs such as aspirin, aristolochic acid, and cisplatin as examples, we confirmed the specificity and precision of cellular drug-target profiles and their associated molecular pathways in tissues using the STEP analysis. Our findings provide more informative insights into the action modes of bioactive molecules compared to in vitro models. Collectively, STEP represents a novel strategy for profiling cellular-specific targets and functional processes with unprecedented resolution.

Features of immune reactivity of the spleen and mechanisms of organ damage under the influence of animal venom toxins including scorpions (review).

Aim: To establish features of immune reactivity of the spleen and mechanisms of organ damage under the influence of animal venom toxins including scorpions. Materials and Methods: A thorough literature analysis was conducted on the basis of PubMed, Google Scholar, Web of Science, and Scopus databases. When processing the search results, we chose the newest publications up to 5 years old or the most thorough publications that vividly described the essence of our topic. Conclusions: Spleen plays a leading role in the implementation of the body's defense processes, the elimination of structural elements affected by toxins, and the restoration of immune homeostasis. Its participation in the formation of the immune response can be accompanied by qualitative and quantitative changes in histological organization. Morpho-functional changes in the spleen under the action of animal venom toxins currently require careful study, because from the information available in the literature today, it is not possible to clearly construct a complete picture of lesions of certain components of the organ at the microscopic or submicroscopic levels. Therefore, this direction of research in the medical field is currently relevant, taking into account the existence of a large number of poisonous animals, including scorpions.