Publications by authors named "Popoff M"

Detection of botulinum neurotoxins (BoNTs) involves a combination of technical challenges that call for the execution of inter-laboratory proficiency tests (PTs) to define the performance and ease of implementation of existing diagnostic methods regarding representative BoNT toxin-types spiked in clinical, food, or environmental matrices. In the framework of the EU project EuroBioTox, we organized an international proficiency test for the detection and quantification of the clinically relevant BoNT/A, B, E, and F sero- and subtypes including concentrations as low as 0.5 ng/mL.

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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.

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The bicentenary of Louis Pasteur's birth raises the opportunity to revisit the activity and influence of L [...

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Humans have faced poisonous animals since the most ancient times. It is recognized that certain animals, like specific plants, produce toxic substances that can be lethal, but that can also have therapeutic or psychoactive effects. The use of the term "venom", which initially designated a poison, remedy, or magic drug, is now confined to animal poisons delivered by biting.

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Article Synopsis
  • - Familial Mediterranean Fever (FMF) is caused by mutations in the MEFV gene, particularly in exon 10, which codes for the B30.2 domain of the pyrin protein, a key player in the body’s inflammatory response.
  • - Researchers found that the B30.2 domain is not essential for activating the pyrin inflammasome in response to bacterial toxins; instead, it acts as a negative regulator.
  • - They also identified the central helical scaffold (CHS) domain, which, along with B30.2, provides distinct regulatory controls on the inflammasome activation, revealing how different mutations can affect inflammation responses in FMF patients.
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Clostridial infections in goats have been associated frequently with enteric diseases or gas gangrene but very rarely with the reproductive system. We describe here 12 cases of fatal postpartum gangrenous metritis in does associated with infection by several clostridial species. Clinically, these cases were characterized by rapid onset of hyperthermia followed by death after kidding.

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The 27th Annual Meeting of the French Society of Toxinology (SFET, http://sfet [...

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Louis Pasteur, one of the eminent pioneers of microbiology, discovered life without oxygen and identified the first anaerobic pathogenic bacterium. Certain bacteria were found to be responsible for specific diseases. Pasteur was mainly interested in the prevention and treatment of infectious diseases with attenuated pathogens.

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The pyrin inflammasome acts as a guard of RhoA GTPases and is central to immune defenses against RhoA-manipulating pathogens. Pyrin activation proceeds in two steps. Yet, the second step is still poorly understood.

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Article Synopsis
  • Botulinum neurotoxins (BoNTs) are highly toxic, but their action mechanism is not fully understood, particularly how they transition under different pH conditions.
  • This study combines modeling and simulations to analyze the dynamics of BoNT/A1 and BoNT/E1 subtypes in both closed and open states, focusing on how pH affects their structure.
  • The results indicate that conformational changes, especially in the belt α-helix and translocation domain, enhance the toxins' mobility and interaction with cell membranes during the translocation process, which is critical for their function.
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Botulinum neurotoxin serotype B (BoNT/B) uses two separate protein and polysialoglycolipid-binding pockets to interact with synaptotagmin 1/2 and gangliosides. However, an integrated model of BoNT/B bound to its neuronal receptors in a native membrane topology is still lacking. Using a panel of in silico and experimental approaches, we present here a new model for BoNT/B binding to neuronal membranes, in which the toxin binds to a preassembled synaptotagmin-ganglioside GT1b complex and a free ganglioside allowing a lipid-binding loop of BoNT/B to interact with the glycone part of the synaptotagmin-associated GT1b.

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The development of anti-infectives against a large range of AB-like toxin-producing bacteria includes the identification of compounds disrupting toxin transport through both the endolysosomal and retrograde pathways. Here, we performed a high-throughput screening of compounds blocking Rac1 proteasomal degradation triggered by the Cytotoxic Necrotizing Factor-1 (CNF1) toxin, which was followed by orthogonal screens against two toxins that hijack the endolysosomal (diphtheria toxin) or retrograde (Shiga-like toxin 1) pathways to intoxicate cells. This led to the identification of the molecule C910 that induces the enlargement of EEA1-positive early endosomes associated with sorting defects of CNF1 and Shiga toxins to their trafficking pathways.

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and are Gram-positive, spore-forming, and anaerobic bacteria that produce the most potent neurotoxins, botulinum toxin (BoNT) and tetanus toxin (TeNT), responsible for flaccid and spastic paralysis, respectively. The main habitat of these toxigenic bacteria is the environment (soil, sediments, cadavers, decayed plants, intestinal content of healthy carrier animals). can grow and produce BoNT in food, leading to food-borne botulism, and in some circumstances, can colonize the intestinal tract and induce infant botulism or adult intestinal toxemia botulism.

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Group I Clostridium botulinum and Clostridium sporogenes are physiologically and genetically closely related. Both are widely distributed in the environment and can cause foodborne botulism. In this work, a physiological study was conducted with 37 isolates from spoiled canned food and five referenced strains of C.

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Article Synopsis
  • Current detection methods include immunological techniques that offer rapid results and mass spectrometry, which is the most sensitive but needs validation for wider use.
  • Cell-based assays using neuronal cells show promise for replacing animal testing in potency determination but require further development due to variability and the need for in vivo studies for safe countermeasures against BoNTs.
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is a potential opportunistic pathogen recovered from faecal samples in cases of necrotizing enterocolitis (NEC), a gastrointestinal disease affecting preterm neonates. Although the species description and name validation were published in 2018, comparative genomics are lacking. In the present study, we provide the closed genome assembly of the ATCC BAA-265 (=250.

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The French Society of Toxinology (SFET) organized its 27th annual meeting on 9-10 December 2021 as a virtual meeting (e-RT27). The central theme of this meeting was "Toxins: Mr Hyde or Dr Jekyll?", emphasizing the latest findings on plant, fungal, algal, animal and bacterial toxins during 10 lectures, 15 oral communications (shorter lectures) and 20 posters shared by ca. 80 participants.

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Clostridium perfringens is a potent producer of a variety of toxins. Well studied from these are five toxins (alpha, Beta (CPB), epsilon, iota and CPE) that are produced by seven toxinotype strains (A-G) of C. perfringens.

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A Gram-positive, anaerobic coccus isolated from a human surgical site infection was previously shown to belong to an unknown species of the genus Peptoniphilus initially proposed as 'Peptoniphilus nemausus' sp. nov., based on both 16S rRNA gene sequence identity of 97.

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Article Synopsis
  • Monoclonal antibodies (mAbs) offer a safer and more reproducible alternative to traditional antisera strategies for treating botulism, a serious illness caused by botulinum neurotoxins (BoNTs).
  • A specific mouse mAb, TA12, was identified as highly effective against BoNT/A1, and this study explored how it neutralizes the toxin through advanced techniques like Hydrogen/Deuterium eXchange Mass Spectrometry (HDX-MS).
  • The research revealed that TA12 targets a unique epitope that overlaps with the binding sites for key neuronal receptors, thereby preventing BoNT/A1 from entering neurons, highlighting the potential of mAbs for botulism treatment.
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Clostridium tetani produces the tetanus toxin (TeNT), one of the most powerful bacterial toxins known to humankind and responsible for tetanus. The regulation of toxin expression is complex and involves the alternative sigma factor TetR as well as other regulators. Here, a transcriptional analysis of the TeNT-encoding large plasmid of C.

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Botulinum neurotoxins (BoNTs) show increasing therapeutic applications ranging from treatment of locally paralyzed muscles to cosmetic benefits. At first, in the 1970s, BoNT was used for the treatment of strabismus, however, nowadays, BoNT has multiple medical applications including the treatment of muscle hyperactivity such as strabismus, dystonia, movement disorders, hemifacial spasm, essential tremor, tics, cervical dystonia, cerebral palsy, as well as secretory disorders (hyperhidrosis, sialorrhea) and pain syndromes such as chronic migraine. This review summarizes current knowledge related to engineering of botulinum toxins, with particular emphasis on their potential therapeutic applications for pain management and for retargeting to non-neuronal tissues.

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Human botulism is a severe disease characterized by flaccid paralysis and inhibition of certain gland secretions, notably salivary secretions, caused by inhibition of neurotransmitter release. Naturally acquired botulism occurs in three main forms: food-borne botulism by ingestion of preformed botulinum neurotoxin (BoNT) in food, botulism by intestinal colonization (infant botulism and intestinal toxemia botulism in infants above one year and adults), and wound botulism. A rapid laboratory confirmation of botulism is required for the appropriate management of patients.

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