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Proteus mirabilis is a leading cause of urinary tract infections and a common commensal of the gastrointestinal tract. Our recent study (JB) showed that P. mirabilis strain BL95 employs a novel contact-dependent killing system against enteric bacteria in the mouse gut and in vitro. To uncover the genetic determinants of this system, we performed whole-genome sequencing of BL95 and compared it with 98 complete genomes of P. mirabilis. BL95 carries 56 coding sequences (CDSs) not found in other P. mirabilis. Over half of these unique genes are located on a novel integrative conjugative element (ICE) named ICEPm2, inserted in tRNA-Phe and exclusive to BL95. ICEPm2 has integration, conjugation, and DNA replication modules nearly identical to ICEPm1 (common in P. mirabilis), but ICEPm2 of BL95 carries two unique operons for P. mirabilis-a phenazine biosynthesis and a contact-dependent growth inhibition (CDI) system. ICEPm2 is absent in the P. mirabilis (AR_0156) closest to BL95 and it is present in the genomes of several Escherichia coli from mouse intestines, indicating its recent horizontal mobilization. BL95 shares over 100 genes of five different secretion systems with other P. mirabilis, mostly poorly studied, making a large pool of candidate genes for the contact-dependent growth inhibition.

Type II toxin-antitoxin systems such as mazEF3, vapBC3, and relJK play a role in antibiotic resistance and tolerance. Among the different known TA systems, mazEF3, vapBC3, and relJK, which are type II systems, have specific roles in drug resistance. Therefore, the aim of this study was to investigate the mutations in these genes in sensitive and resistant isolates of Mycobacterium tuberculosis. Thirty-two rifampin-resistant and 121 rifampin-sensitive M. tuberculosis isolates were collected from various regions of Iran. Lineage typing was performed using the ASO-PCR method. Mutations in the rpoB gene were analyzed in all isolates by MAS-PCR. Furthermore, mutations in the mazEF3, relJK, and vapBC3 genes of the type II toxin system were assessed through PCR sequencing. These sequences were analyzed using COBALT and SnapGene 2017, and submitted to the GenBank database. Among the 153 M. tuberculosis samples, lineages 4, 3 and 2 were the most common. Lineage 2 had the highest rate of rifampin resistance. Mutations in rpoB531 were the most frequent in resistant isolates. Examination of the toxin-antitoxin system showed that rifampin-resistant isolates belonging to lineage 3 had mutations in either the toxin or antitoxin parts of all three TA systems. A mutation in nucleotide 195 (codon 65) of mazF3 leading to an amino acid change from threonine to isoleucine was detected in all rifampin-resistant isolates. M. tuberculosis isolates belonging to lineage 2 exhibited the highest rifampin resistance in our study. Identifying the mutation in mazF3 in all rifampin-resistant isolates can highlight the significance of this mutation in the development of drug resistance in M. tuberculosis. Expanding the sample size in future studies can help develop a new method for identifying resistant isolates. [ABSTRACT FROM AUTHOR]

The extremely rich palaeontological record of the horse family, also known as equids, has provided many examples of macroevolutionary change over the last ~55 Mya. This family is also one of the most documented at the palaeogenomic level, with hundreds of ancient genomes sequenced. While these data have advanced understanding of the domestication history of horses and donkeys, the palaeogenomic record of other equids remains limited. In this study, we have generated genome‐wide data for 25 ancient equid specimens spanning over 44 Ky and spread across Anatolia, the Caucasus, Central Asia and Mongolia. Our dataset includes the genomes from two extinct species, the European wild ass, Equus hydruntinus, and the sussemione Equus ovodovi. We document, for the first time, the presence of sussemiones in Mongolia and their survival around ~3.9 Kya, a finding that should be considered when discussing the timing of the first arrival of the domestic horse in the region. We also identify strong spatial differentiation within the historical ecological range of Asian wild asses, Equus hemionus, and incomplete reproductive isolation in several groups yet considered as different species. Finally, we find common selection signatures at ANTXR2 gene in European, Asian and African wild asses. This locus, which encodes a receptor for bacterial toxins, shows no selection signal in E. ovodovi, but a 5.4‐kb deletion within intron 7. Whether such genetic modifications played any role in the sussemione extinction remains unknown. [ABSTRACT FROM AUTHOR]

The increasing prevalence of neurological disorders such as Alzheimer's, Parkinson's, and multiple sclerosis presents a significant global health challenge. Despite extensive research, the precise mechanisms underlying these conditions remain elusive, with current treatments primarily addressing symptoms rather than root causes. Emerging evidence suggests that gut permeability and the kynurenine pathway are involved in the pathogenesis of these neurological conditions, offering promising targets for novel therapeutic and preventive strategies. Gut permeability refers to the intestinal lining's ability to selectively allow essential nutrients into the bloodstream while blocking harmful substances. Various factors, including poor diet, stress, infections, and genetic predispositions, can compromise gut integrity, leading to increased permeability. This condition facilitates the translocation of toxins and bacteria into systemic circulation, triggering widespread inflammation that impacts neurological health via the gut–brain axis. The gut–brain axis (GBA) is a complex communication network between the gut and the central nervous system. Dysbiosis, an imbalance in the gut microbiota, can increase gut permeability and systemic inflammation, exacerbating neuroinflammation—a key factor in neurological disorders. The kynurenine pathway, the primary route for tryptophan metabolism, is significantly implicated in this process. Dysregulation of the kynurenine pathway in the context of inflammation leads to the production of neurotoxic metabolites, such as quinolinic acid, which contribute to neuronal damage and the progression of neurological disorders. This narrative review highlights the potential and progress in understanding these mechanisms. Interventions targeting the kynurenine pathway and maintaining a balanced gut microbiota through diet, probiotics, and lifestyle modifications show promise in reducing neuroinflammation and supporting brain health. In addition, pharmacological approaches aimed at modulating the kynurenine pathway directly, such as inhibitors of indoleamine 2,3-dioxygenase, offer potential avenues for new treatments. Understanding and targeting these interconnected pathways are crucial for developing effective strategies to prevent and manage neurological disorders. [ABSTRACT FROM AUTHOR]

Biofilms are complex bacterial communities characterized by a high persister prevalence, which contributes to chronic and relapsing infections. Historically, persister formation in biofilms has been linked to constraints imposed by their dense structures. However, we observed an elevated persister frequency accompanying the stage of cell adhesion, marking the onset of biofilm development. Subsequent mechanistic studies uncovered a comparable type of toxin-antitoxin (TA) module (TA-like system) triggered by cell adhesion, which is responsible for this elevation. In this module, the toxin HipH acts as a genotoxic deoxyribonuclease, inducing DNA double strand breaks and genome instability. While the second messenger c-di-GMP functions as the antitoxin, exerting control over HipH expression and activity. The dynamic interplay between c-di-GMP and HipH levels emerges as a crucial determinant governing genome stability and persister generation within biofilms. These findings unveil a unique TA system, where small molecules act as the antitoxin, outlining a biofilm-specific molecular mechanism influencing genome stability and antibiotic persistence, with potential implications for treating biofilm infections. [ABSTRACT FROM AUTHOR]

Bacterial infections, especially those caused by multidrug‐resistant pathogens, pose a significant threat to public health. Vaccines are a crucial tool in fighting these infections; however, no clinically available vaccine exists for the most common bacterial infections, such as those caused by Pseudomonas aeruginosa. Herein, a multiantigenic antibacterial nanovaccine (AuNP@HMV@SPs) is reported to combat P. aeruginosa infections. This nanovaccine utilizes the hybrid membrane vesicles (HMVs) created by fusing macrophage membrane vesicles (MMVs) with bacterial outer membrane vesicles (OMVs). The HMVs mitigate the toxic effects of both OMVs and bacterial secreted toxins (SP) adsorbed on the surface of MMVs, while preserving their stimulating properties. Gold nanoparticles (AuNPs) are utilized as adjuvant to enhance immune response without comprising safety. The nanovaccine AuNP@HMV@SPs induces robust humoral and cellular immune responses, leading to destruction of bacterial cells and neutralization of their secreted toxins. In murine models of septicemia and pneumonia caused by P. aeruginosa, AuNP@HMV@SPs exhibits superior prophylactic efficacy compared to control groups including OMVs, or MMVs@SPs and HMV@SPs, achieving 100% survival in septicemia and > 99.9% reduction in lung bacterial load in pneumonia. This study highlights AuNP@HMV@SPs as a safe and effective antibacterial nanovaccine, targeting both bacteria and their secreted toxins, and offers a promising platform for developing multiantigenic antibacterial vaccines against multidrug‐resistant pathogens. [ABSTRACT FROM AUTHOR]

Simple Summary: Acute hepatopancreatic necrosis disease (AHPND) is a plasmid-encoded PirA/B toxin mediated bacterial disease that causes significant economic losses to the global shrimp industry. Since the first AHPND outbreak of Penaeus vannamei cultures in Korea in 2016, AHPND-associated Vibrio parahaemolyticus (VpAHPND) is still considered a major threat to the Korean shrimp industry. Although several diagnostic methods have been developed against AHPND, several concerns have been raised about the misdiagnosis of the pathogen due to the transferability and mutation of the plasmid. In this study, we report the emergence of a natural mutant VpAHPND (pirA−, pirB+), which was isolated from cultured P. vannamei in Korea, and also provide its detailed genomic and pathological characteristics. Acute hepatopancreatic necrosis disease (AHPND) is one of the most important diseases in the global shrimp industry. The emergence of mutant AHPND-associated V. parahaemolyticus (VpAHPND) strains has raised concerns regarding potential misdiagnosis and unforeseen pathogenicity. In this study, we report the first emergence of a type II (pirA−, pirB+) natural mutant, VpAHPND (strain 20-082A3), isolated from cultured Penaeus vannamei in Korea. Phenotypic and genetic analyses revealed a close relationship between the mutant strain 20-082A3 and the virulent Korean VpAHPND strain 19-021-D1, which caused an outbreak in 2019. Detailed sequence analysis of AHPND-associated plasmids showed that plasmid pVp_20-082A3B in strain 20-082A3 was almost identical (>99.9%) to that of strain 19-021-D1. Moreover, strains 20-082A3 and 19-021-D1 exhibited the same multilocus sequence type (ST 413) and serotype (O1:Un-typeable K-serogroup), suggesting that the mutant strain is closely related to and may have originated from the virulent strain 19-021-D1. Similar to previous reports on the natural mutant VpAHPND, strain 20-082A3 did not induce AHPND-related symptoms or cause mortality in the shrimp bioassay. The emergence of a mutant strain which is almost identical to the virulent VpAHPND highlights the need for surveillance of the pathogen prevalent in Korea. Further investigations to elucidate the potential relationship between ST 413 and recent Korean VpAHPND isolates are needed. [ABSTRACT FROM AUTHOR]

Opioid receptors are found throughout the gastrointestinal tract, including the large intestine. Many patients treated with opioids experience opioid-induced constipation (OIC). Laxatives are not effective in most patients, and in those who do initially respond, the efficacy of laxatives generally diminishes over time. In addition, OIC does not spontaneously resolve for most patients. However, complications of opioids extend far beyond simply slowing gastrointestinal transit. Opioid use can affect intestinal permeability through a variety of mechanisms. Toll-like receptors are a crucial component of innate immunity and are tightly regulated within the gut epithelium. Pathologic m-opioid receptor (MOR) and toll-like receptor signaling, resulting from chronic opioid exposure, disrupts intestinal permeability leading to potentially harmful bacterial translocation, elevated levels of bacterial toxins, immune activation, and increased cytokine production. Peripherally active MOR antagonists, including methylnaltrexone, are effective at treating OIC. Benefits extend beyond simply blocking the MOR; these agents also act to ameliorate opioid-induced disrupted intestinal permeability. In this review, we briefly describe the physiology of the gastrointestinal epithelial border and discuss the impact of opioids on gastrointestinal function. Finally, we consider the use of peripherally activeMORantagonists to treat disrupted intestinal permeability resulting from opioid use and discuss the potential for improved morbidity and mortality in patients treated with methylnaltrexone for opioid-induced bowel disorders. [ABSTRACT FROM AUTHOR]

Bacterial toxin‐antitoxin (TA) systems consist of a toxin that inhibits essential cellular processes, such as DNA replication, transcription, translation, or ATP synthesis, and an antitoxin neutralizing their cognate toxin. These systems have roles in programmed cell death, defense against phage, and the formation of persister cells. Here, we characterized the previously identified Staphylococcus aureus TA system, tsaAT, which consists of two putative membrane proteins: TsaT and TsaA. Expression of the TsaT toxin caused cell death and disrupted membrane integrity, whereas TsaA did not show any toxicity and neutralized the toxicity of TsaT. Furthermore, subcellular fractionation analysis demonstrated that both TsaA and TsaT localized to the cytoplasmic membrane of S. aureus expressing either or both 3xFLAG‐tagged TsaA and 3xFLAG‐tagged TsaT. Taken together, these results demonstrate that the TsaAT TA system consists of two membrane proteins, TsaA and TsaT, where TsaT disrupts membrane integrity, ultimately leading to cell death. Although sequence analyses showed that the tsaA and tsaT genes were conserved among Staphylococcus species, amino acid substitutions between TsaT orthologs highlighted the critical role of the 6th residue for its toxicity. Further amino acid substitutions indicated that the glutamic acid residue at position 63 in the TsaA antitoxin and the cluster of five lysine residues in the TsaT toxin are involved in TsaA's neutralization reaction. This study is the first to describe a bacterial TA system wherein both toxin and antitoxin are membrane proteins. These findings contribute to our understanding of S. aureus TA systems and, more generally, give new insight into highly diverse bacterial TA systems. [ABSTRACT FROM AUTHOR]

[Display omitted] The skin has a multilayered structure, and deep-seated injuries are exposed to external microbial invasion and in vivo microenvironmental destabilization. Here, a bilayer bionic skin scaffold (Bilayer SF) was developed based on methacrylated sericin protein to mimic the skin's multilayered structure and corresponding functions. The outer layer (SF@TA), which mimics the epidermal layer, was endowed with the function of resisting external bacterial and microbial invasion using a small pore structure and bio-crosslinking with tannic acid (TA). The inner layer (SF@DA@Gel), which mimics the dermal layer, was used to promote cellular growth using a large pore structure and introducing dopamine (DA) to regulate the wound microenvironment. This Bilayer SF showed good mechanical properties and structural stability, satisfactory antioxidant and promote cell proliferation and migration abilities. In vitro studies confirmed the antimicrobial properties of the outer layer and the pro-angiogenic ability of the inner layer. In vivo animal studies demonstrated that the bilayer scaffolds promoted collagen deposition, neovascularization, and marginal hair follicle formation, which might be a promising new bionic skin scaffold. [ABSTRACT FROM AUTHOR]

The western corn rootworm, (Diabrotica virgifera virgifera LeConte, Coleoptera: Chrysomelidae), is a serious pest of corn (Zea mays Linnaeus, Cyperales: Poaceae) in the midwestern United States. Management practices for corn rootworm larvae include crop rotation, transgenic corn producing insecticidal toxins from the bacterium Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) (Bt), and soil-applied insecticides. The extent to which combining soil-applied insecticide with Bt corn would be beneficial from the perspective of insect resistance management (IRM) or integrated pest management (IPM) remains uncertain. We conducted a 3-yr field study to characterize the implications of combining a soil-applied insecticide and Bt corn for IRM and IPM of western corn rootworm. Experimental treatments were Bt corn, a soil-applied insecticide, the combination of these factors, and an experimental control in which both factors were absent. Data were collected on root injury to corn by rootworm, survival to adulthood, adult size, and emergence time for western corn rootworm. We found that mortality caused by the soil-applied insecticide was insufficient to delay resistance to Bt corn. While combining Bt corn and a soil-applied insecticide may provide a short-term economic benefit, additional research is needed to determine appropriate economic thresholds for combining these tactics. Additionally, combining a soil-applied insecticide and Bt corn would not be sustainable over multiple growing seasons because of its potential to rapidly select for Bt resistance. In general, a more sustainable IRM strategy for rootworm management would include using crop rotation and alternating between non-Bt corn with soil-applied insecticide and Bt corn without soil-applied insecticide. [ABSTRACT FROM AUTHOR]

Many bacteria act pathogenic by the release of AB-type protein toxins that efficiently enter human or animal cells and act as enzymes in their cytosol. This leads to disturbed cell functions and the clinical symptoms characteristic for the individual toxin. Therefore, molecules that directly target and neutralize these toxins provide promising novel therapeutic options. Here, we found that the FDA-approved drug disulfiram (DSF), used for decades to treat alcohol abuse, protects cells from intoxication with diphtheria toxin (DT) from Corynebacterium diphtheria, the causative agent of diphtheria, lethal toxin (LT) from Bacillus anthracis, which contributes to anthrax, and C2 enterotoxin from Clostridium botulinum when applied in concentrations lower than those found in plasma of patients receiving standard DSF treatment for alcoholism (up to 20 µM). Moreover, this inhibitory effect is increased by copper, a known enhancer of DSF activity. LT and C2 are binary toxins, consisting of two non-linked proteins, an enzyme (A) and a separate binding/transport (B) subunit. To act cytotoxic, their proteolytically activated B subunits PA63 and C2IIa, respectively, form barrelshaped heptamers that bind to their cellular receptors and form complexes with their respective A subunits LF and C2I. The toxin complexes are internalized via receptor-mediated endocytosis and in acidified endosomes, PA63 and C2IIa form pores in endosomal membranes, which facilitate translocation of LF and C2I into the cytosol, where they act cytotoxic. In DT, A and B subunits are located within one protein, but DT also forms pores in endosomes that facilitate translocation of the A subunit. If cell binding, membrane translocation, or substrate modification is inhibited, cells are protected from intoxication. Our results implicate that DSF neither affects cellular binding nor the catalytic activity of the investigated toxins to a relevant extend, but interferes with the toxin pore-mediated translocation of the A subunits of DT, LT and C2 toxin, as demonstrated by membranetranslocation assays and toxin pore conductivity experiments in the presence or absence of DSF. Since toxin translocation across intracellular membranes represents a central step during cellular uptake of many bacterial toxins, DSF might neutralize a broad spectrum of medically relevant toxins. [ABSTRACT FROM AUTHOR]

Intracellular bacterial (ICB) infection is one of the most life‐threatening cases of drug resistance, and photodynamic therapy (PDT) is challenged by limited light penetration into tissues and unspecific toxicity to host cells. Herein, theranostic nanoparticles (NPs) are developed to facilitate on‐demand activation of photosensitizers inside ICBs and persistent PDT of deep‐tissue ICB infections. Mechanoluminescent SrAl2O4:Eu2+ and persistence luminescent CaS:Eu2+ are sequentially deposited on mesoporous silica to prepare mSC, followed by encapsulation by bacterial membranes with loaded nitroreductase (NTR)‐activatable methylene blue (nMB) to obtain mSC‐nMB@BM NPs. The fluorescence quenching of nMB with mSC offers few cytotoxicities even under ultrasonication, and bacterial membrane coatings mediate the specific NP internalization into ICB‐infected macrophages. Bacterial pore‐forming toxins trigger nMB release from NPs, and intrabacterial NTR rejuvenates methylene blue probes from nMB for real‐time imaging of ICB infections. Ultrasonication of NPs continuously excites the rejuvenated methylene blue to generate reactive oxidative species and reduce viable ICBs by 3.54 log magnitude folds. NP treatment on ICB‐infected mice exhibits full survival and restores viscera functions without any pathological abnormality. Therefore, this concise NP design demonstrates capabilities of bacterial membrane‐mediated specific internalization, bacterial toxin‐triggered release and intrabacterial NTR‐rejuvenation of fluorescent probes, and persistent internal light‐illumination for ICB theranostics. [ABSTRACT FROM AUTHOR]

Melatonin (N-acetyl-5-methoxytryptamine) is an essential small molecule with diverse biological functions. It plays several key roles, including regulating the secretion of reproductive hormones and the reproductive cycle, enhancing the functionality of reproductive organs, improving the quality of sperm and eggs, and mitigating oxidative stress in the reproductive system. Melatonin effectively inhibits and scavenges excess free radicals while activating the antioxidant enzyme system and reduces the production of inflammatory factors and alleviates tissue damage caused by inflammation by regulating inflammatory pathways. Additionally, melatonin contributes to repairing the intestinal barrier and regulating the gut microbiota, thereby reducing bacterial and toxin permeation. The use of melatonin as an endogenous hormone in animal husbandry has garnered considerable attention because of its positive effects on animal production performance, reproductive outcomes, stress adaptation, disease treatment, and environmental sustainability. This review explores the characteristics and biological functions of melatonin, along with its current applications in animal production. Our findings may serve as a reference for the use of melatonin in animal farming and future developmental directions. [ABSTRACT FROM AUTHOR]

Probiotic organisms are increasingly being incorporated into foods in order to develop products to prevent and reduce many diseases. Saccharomyces boulardii, a probiotic yeast with unique properties, such as viability over a wide pH range, antibiotic resistance, and the ability to reach a steady state, has an advantage over bacterial probiotics. The present review highlights the potential application of S. boulardii in functional fermented dairy products and the genetic engineering of this probiotic microorganism as a therapeutic agent for the treatment of various infectious diseases. It was found that probiotic yeast stimulates the growth of lactic acid bacteria in dairy products, creating favorable conditions and positively affecting the product's sensory characteristics. Moreover, its viability of more than 106 cfu/mL at the end of the yogurt shelf life confirms its probiotic effect. On the other hand, there is a growing interest in the design of probiotic strains to improve their characteristics and fill existing gaps in their spectrum of action such as the inhibition of some bacterial toxins, as well as anti-inflammatory and immunomodulatory effects. The strengthening of immune functions and effective therapies against various diseases by S. boulardii was confirmed. However, considering this yeast species' potential, further research is necessary to accurately determine the functional properties in terms of incorporation into food matrices and from the aspect of health and well-being claims. [ABSTRACT FROM AUTHOR]

Background: Microbial larvicides containing both LysiniBacillus sphaericus and Bacillus thuringiensis svar. israelensis (Bti) insecticidal crystals can display advantages for mosquito control. This includes a broader action against larvae that are refractory to the Binary (Bin) toxin from L. sphaericus, as Bin-resistant Culex quinquefasciatus and Aedes aegypti naturally refractory larvae, which often co-habit urban areas of endemic countries for arboviruses. Our principal goal was to assess the toxicity of a combined L. sphaericus/Bti larvicide (Vectomax FG™) to Cx. quinquefasciatus (susceptible CqS and Bin-resistant CqR) and Ae. aegypti (Rocke) and to determine its persistence in the breeding sites with those larvae. Methods: The toxicity of a combined L. sphaericus/Bti product (VectoMax FG™) to larvae was performed using bioassays, and persistence was evaluated in simulate field trials carried out under the shade, testing two label concentrations during 12 weeks. A laboratory strain SREC, established with CqS and CqR larvae, was kept during four generations to evaluate the ability of the L. sphaericus/Bti to eliminate resistant larvae. Results: The L. sphaericus/Bti showed toxicity (mg/L) to larvae from all strains with a decreasing pattern for CqS (LC50 = 0.006, LC90 = 0.030), CqR (LC50 = 0.009, LC90 = 0.069), and Rocke (LC50 = 0.042, LC90 = 0.086). In a simulated field trial, the larvicide showed a persistence of 6 weeks and 8 weeks, controlling larvae from all strains in containers with 100 L of water, using 2 g or 4 g per container (100 L), respectively. The treatment of SREC larvae with L. sphaericus/Bti showed its capacity to eliminate the Bin-resistant individuals using suitable concentrations to target those larvae. Conclusions: Our results showed the high efficacy and persistence of the L. sphaericus/Bti larvicide to control Cx. quinquefasciatus and Ae. aegypti that might cohabit breeding sites. These findings demonstrated that such larvicides can be an effective tool for controlling those species in urban areas with a low potential for selecting resistance. [ABSTRACT FROM AUTHOR]

A severe consequence of SARS-CoV-2 infection that manifests as systemic inflammation and multi-organ involvement is called Multisystem Inflammatory Syndrome in Children (MIS-C). This review examines the possible relationship between gut barrier integrity, the microbiome, dysregulation of interleukin 6 (IL-6) signaling, and MIS-C. Clinical and biochemical features of MIS-C are comparable to those of other hyper-inflammatory syndromes, suggesting a dysregulated immune response. One possible explanation for the systemic inflammation seen in MIS-C patients is the SARS-CoV-2-induced dysregulation of the IL-6 signaling pathway. In addition, new data suggest a reciprocal link between gut barrier integrity and IL-6. SARS-CoV-2 exhibits bacteriophage-like behavior, highlighting the role of bacteria as a reservoir for the virus and emphasizing the importance of understanding the bacteriophagic mechanism of the virus in fecal–oral transmission. The increased translocation of viral products and bacterial toxins may result from disrupting the intestinal barrier and cause systemic inflammation. On the other hand, systemic inflammation can weaken the integrity of the intestinal barrier, which feeds back into the loop of immunological dysregulation. In the context of MIS-C, understanding the interaction between SARS-CoV-2 infection, IL-6, and gut barrier integrity may shed light on the etiology of the disease and guide treatment options. Since children with gut dysbiosis may be more susceptible to MIS-C, it is critical to reinforce their microbiome through probiotics supplementation, and plant-fiber-rich diets (prebiotics). Early antibiotic treatment and the use of zonulin antagonists should also be considered. [ABSTRACT FROM AUTHOR]

Mycobacterium phage Adephagia is a cluster K phage that infects Mycobacterium smegmatis and some strains of Mycobacterium pathogens. Adephagia has a siphoviral virion morphology and is temperate. Its genome is 59,646 bp long and codes for one tRNA gene and 94 predicted protein-coding genes; most genes not associated with virion structure and assembly are functionally ill-defined. Here, we determined the Adephagia gene expression patterns in lytic and lysogenic growth and used structural predictions to assign additional gene functions. We characterized 66 nonstructural genes for their toxic phenotypes when expressed in M. smegmatis , and we show that 25 of these (38%) are either toxic or strongly inhibit growth, resulting in either reduced viability or small colony sizes. Some of these genes are predicted to be involved in DNA metabolism or regulation, but others are of unknown function. We also characterize the HicAB-like toxin–antitoxin (TA) system encoded by Adephagia (gp91 and gp90, respectively) and show that the gp90 antitoxin is lysogenically expressed, abrogates gp91 toxicity, and is required for normal lytic and lysogenic growth. [ABSTRACT FROM AUTHOR]

Furin, a serine protease enzyme located in the Golgi apparatus of animal cells, plays a crucial role in cleaving precursor proteins into their mature, active forms. It is ubiquitously expressed across various tissues, including the brain, lungs, gastrointestinal tract, liver, pancreas, and reproductive organs. Since its discovery in 1990, furin has been recognized as a significant therapeutic target, leading to the active development of furin inhibitors for potential use in antiviral, antibacterial, anticancer, and other therapeutic applications. This review provides a comprehensive overview of the progress in the development and characterization of furin inhibitors, encompassing peptides, linear and macrocyclic peptidomimetics, and non-peptide compounds, highlighting their potential in the treatment of both infectious and non-infectious diseases. [ABSTRACT FROM AUTHOR]

Intestinal mucus serves as the first line barrier within the mucosa to protect against microbiota attack due to its water-repellent properties, which are the result of the high abundance of phosphatidylcholine bound to mucins. A deficiency of mucus phosphatidylcholine predisposes it to mucosal inflammation by the attack of commensal microbiota, as it is intrinsically low in ulcerative colitis. However, for precipitation of an acute inflammatory episode, mucus phosphatidylcholine has to fall below the critical level required for mucosal protection. Bacterial ectophospholipase could be a candidate for further thinning of the mucus phosphatidylcholine shield as shown, for example, with the ectophospholipase containing Helicobacter pylori bacterium. Despite supporting evidence for this mechanism in the intestine, the responsible ectophospholipase-carrying bacteria species are still to be defined. Applying phosphatidylcholine to the lumen can serve to fill up empty mucin-binding sites in ulcerative colitis as well as provide a substrate for the ectophospholipase-carrying bacteria preventing their attacks on the mucus phosphatidylcholine layer. Evidence supporting this concept comes from clinical trials in humans with ulcerative colitis as well as from colitis mouse models where phosphatidylcholine was substituted in the lumen. An alternative strategy could involve adding non-absorbable phospholipase inhibitors to the intestinal lumen, which has been shown to be effective in a mouse model of ulcerative colitis. Bacterial phospholipase should be considered a pathogenetic factor of the intestinal microbiota and therapeutic strategies should be developed to prevent their hyperactivity for clinical improvement of intestinal inflammation. [ABSTRACT FROM AUTHOR]

The food industry is unceasingly searching for accurate ways to check food safety. The presence of microbial toxins such as bacterial toxins, fungal toxins, and algal toxins in food products has become a concerning issue worldwide. These toxins can contaminate food during various stages of its production, transportation, and storage, posing a serious threat to human health. The reliable and quick determination of microbial toxins has become significant for eliminating the disease outbreaks caused by contaminated foodstuffs. Thus, there is an increased interest in developing low-cost and high-throughput sensors for the determination of microbial toxins in food matrices. Recently, fluorescent sensors have gained importance as one of the effective alternatives in food safety monitoring. The use of nanomaterials in the fabrication of fluorescent sensors has imparted amazing properties such as high selectivity and sensitivity, rapid results, good stability, and reproducibility to analyze microbial toxins in real food matrices. The present review summarizes the recent developments in nanomaterial-based fluorescent sensors for the detection of microbial toxins in food products. The review delves into the details of various fluorescent nanomaterials such as metal-based nanomaterials, upconversion nanoparticles, semiconductor quantum dots, carbon-based nanomaterials, and luminescent metal-organic frameworks describing their unique properties, advantages, drawbacks, and applications in the detection of microbial toxins in food products. Also, the performance comparison of the fluorescent nanomaterials in the detection of these toxins has been discussed. Further, the commercial aspects of fluorescent nanosensors for the detection of microbial toxins have been included, along with the future insights and challenges associated with microbial toxin detection. [ABSTRACT FROM AUTHOR]

Wound infection causes wound chronicity as the presence of pathogens prolong wound healing time. Endotoxins lipopolysaccharides (LPS) are released from Gram-negative bacteria when they are lysed by host phagocytic cells during an immune response. These endotoxins in wounds are shown to be one of the causes of delayed wound healing. The porous activated carbon (AC) can act as an important absorptive material for the elimination of bacterial toxins, which makes it an attractive biomaterial for infected wounds. NCC is also reported to facilitate cell adhesion, proliferation, and migrations. Previously, our laboratory has shown that chitosan (CS) reinforced with Kenaf nanocrystalline celluloses (NCC) possesses vastly improved mechanical properties. This study explores the potential of incorporating AC into NCC-CS hydrogel (AC/NCC), with the aim of eliminating bacteria toxins in wounds as well as the acceleration of wound healing. The AC/NCC hydrogel was characterized in terms of rheological properties, swelling behaviour, fourier transform infrared spectroscopy as well as zeta potential. Then the AC/NCC hydrogel dressings were evaluated in vitro using a cytotoxicity study and toxin removal assay. The results showed that hydrogels exhibit desirable rheological properties with homogenous activated carbon particles. The hydrogels exhibit low cytotoxicity towards the human fibroblast and keratinocytes cells. The hydrogel can remove up to 85% of endotoxins when treated with 0.1 EU/mL of LPS. In summary, this study has shown that AC/NCC hydrogel has a vast potential as an antitoxin dressing for infected chronic wounds. AC/NCC hydrogel dressing eliminates endotoxin from infected wounds and accelerates wound healing [ABSTRACT FROM AUTHOR]

Inhibitors of the serine protease furin have been widely studied as antimicrobial agents due to their ability to block the cleavage and activation of certain viral surface proteins and bacterial toxins. In this study, the antipseudomonal effects and safety profiles of the furin inhibitors MI-1851 and MI-2415 were assessed. Fluorescence quenching studies suggested no relevant binding of the compounds to human serum albumin and α1-acid glycoprotein. Both inhibitors demonstrated significant antipseudomonal activity in Madin–Darby canine kidney cells, especially compound MI-1851 at very low concentrations (0.5 µM). Using non-tumorigenic porcine IPEC-J2 cells, neither of the two furin inhibitors induced cytotoxicity (CCK-8 assay) or altered significantly the intracellular (Amplex Red assay) or extracellular (DCFH-DA assay) redox status even at a concentration of 100 µM. The same assays with MI-2415 conducted on primary human hepatocytes also resulted in no changes in cell viability and oxidative stress at up to 100 µM. Microsomal and hepatocyte-based CYP3A4 activity assays showed that both inhibitors exhibited a concentration-dependent inhibition of the isoenzyme at high concentrations. In conclusion, this study indicates a good safety profile of the furin inhibitors MI-1851 and MI-2415, suggesting their applicability as antimicrobials for further in vivo investigations, despite some inhibitory effects on CYP3A4. [ABSTRACT FROM AUTHOR]

Abstract Background Microbial larvicides containing both LysiniBacillus sphaericus and Bacillus thuringiensis svar. israelensis (Bti) insecticidal crystals can display advantages for mosquito control. This includes a broader action against larvae that are refractory to the Binary (Bin) toxin from L. sphaericus, as Bin-resistant Culex quinquefasciatus and Aedes aegypti naturally refractory larvae, which often co-habit urban areas of endemic countries for arboviruses. Our principal goal was to assess the toxicity of a combined L. sphaericus/Bti larvicide (Vectomax FG™) to Cx. quinquefasciatus (susceptible CqS and Bin-resistant CqR) and Ae. aegypti (Rocke) and to determine its persistence in the breeding sites with those larvae. Methods The toxicity of a combined L. sphaericus/Bti product (VectoMax FG™) to larvae was performed using bioassays, and persistence was evaluated in simulate field trials carried out under the shade, testing two label concentrations during 12 weeks. A laboratory strain SREC, established with CqS and CqR larvae, was kept during four generations to evaluate the ability of the L. sphaericus/Bti to eliminate resistant larvae. Results The L. sphaericus/Bti showed toxicity (mg/L) to larvae from all strains with a decreasing pattern for CqS (LC50 = 0.006, LC90 = 0.030), CqR (LC50 = 0.009, LC90 = 0.069), and Rocke (LC50 = 0.042, LC90 = 0.086). In a simulated field trial, the larvicide showed a persistence of 6 weeks and 8 weeks, controlling larvae from all strains in containers with 100 L of water, using 2 g or 4 g per container (100 L), respectively. The treatment of SREC larvae with L. sphaericus/Bti showed its capacity to eliminate the Bin-resistant individuals using suitable concentrations to target those larvae. Conclusions Our results showed the high efficacy and persistence of the L. sphaericus/Bti larvicide to control Cx. quinquefasciatus and Ae. aegypti that might cohabit breeding sites. These findings demonstrated that such larvicides can be an effective tool for controlling those species in urban areas with a low potential for selecting resistance. Graphical Abstract

Wnt signaling pathways are transmitted via 10 homologous frizzled receptors (FZD1-10) in humans. Reagents broadly inhibiting Wnt signaling pathways reduce growth and metastasis of many tumors, but their therapeutic development has been hampered by the side effect. Inhibitors targeting specific Wnt-FZD pair(s) enriched in cancer cells may reduce side effect, but the therapeutic effect of narrow-spectrum Wnt-FZD inhibitors remains to be established in vivo. Here, we developed a fragment of C. difficile toxin B (TcdBFBD), which recognizes and inhibits a subclass of FZDs, FZD1/2/7, and examined whether targeting this FZD subgroup may offer therapeutic benefits for treating breast cancer models in mice. Utilizing 2 basal-like and 1 luminal-like breast cancer models, we found that TcdBFBD reduces tumor-initiating cells and attenuates growth of basal-like mammary tumor organoids and xenografted tumors, without damaging Wnt-sensitive tissues such as bones in vivo. Furthermore, FZD1/2/7-positive cells are enriched in chemotherapy-resistant cells in both basal-like and luminal mammary tumors treated with cisplatin, and TcdBFBD synergizes strongly with cisplatin in inhibiting both tumor types. These data demonstrate the therapeutic value of narrow-spectrum Wnt signaling inhibitor in treating breast cancers.

Clostridioides difficile infection (CDI) is a major cause of healthcare-associated gastrointestinal infections1,2. The exaggerated colonic inflammation caused by C. difficile toxins such as toxin B (TcdB) damages tissues and promotes C. difficile colonization3-6, but how TcdB causes inflammation is unclear. Here we report that TcdB induces neurogenic inflammation by targeting gut-innervating afferent neurons and pericytes through receptors, including the Frizzled receptors (FZD1, FZD2 and FZD7) in neurons and chondroitin sulfate proteoglycan 4 (CSPG4) in pericytes. TcdB stimulates the secretion of the neuropeptides substance P (SP) and calcitonin gene-related peptide (CGRP) from neurons and pro-inflammatory cytokines from pericytes. Targeted delivery of the TcdB enzymatic domain, through fusion with a detoxified diphtheria toxin, into peptidergic sensory neurons that express exogeneous diphtheria toxin receptor (an approach we term toxogenetics) is sufficient to induce neurogenic inflammation and recapitulates major colonic histopathology associated with CDI. Conversely, mice lacking SP, CGRP or the SP receptor (neurokinin 1 receptor) show reduced pathology in both models of caecal TcdB injection and CDI. Blocking SP or CGRP signalling reduces tissue damage and C. difficile burden in mice infected with a standard C. difficile strain or with hypervirulent strains expressing the TcdB2 variant. Thus, targeting neurogenic inflammation provides a host-oriented therapeutic approach for treating CDI.

Background: Food safety is of utmost importance to sustaining life and promoting good health and is a main problem in any country, regardless of economic and social development. Unsafe food containing harmful pathogens and their toxins cause hundreds of diseases, particularly affecting infants, young children, the elderly and sick people. Therefore, the rapid detection of foodborne pathogens is of great significance for public health. The aim of this review was to provide comprehensive information regarding methods for the detection of foodborne pathogens as well as genus Fusarium and their toxins, from fundamental to state-of-the-art, presenting their advantages and limitations in order to update current knowledge. Review Results: The traditional culture-based methods for the detection of pathogens in food are usually laborious, limited by complex sample preparation procedures, time-consuming, slow to provide results, and require well-trained professional staff. However, compared to these methods, the new ones - immunological methods, nucleic acid-based assays and biosensor-based methods are rapid, accurate, highly sensitive and specific, and easy to use. Precisely providing accurate real-time results would help limit foodborne disease outbreaks, ensure compliance with legislation setting maximum levels of pathogens in certain food categories, detect and improve the import of food contaminated with dangerous levels of pathogenic microorganisms, and ensure public health safety. Conclusion: The development of rapid and automated methods that detect real-time, small numbers of viable microbial cells within a given volume of food is vital in the prevention, transmission and treatment of foodborne diseases. Such methods would also offer a great commercial advantage in the food industry and related fields

Mitochondria are essential organelles known to serve broad functions, including in cellular metabolism, calcium buffering, signaling pathways and the regulation of apoptotic cell death. Maintaining the integrity of the outer (OMM) and inner mitochondrial membranes (IMM) is vital for mitochondrial health. Cardiolipin (CL), a unique dimeric glycerophospholipid, is the signature lipid of energy‐converting membranes. It plays a significant role in maintaining mitochondrial architecture and function, stabilizing protein complexes and facilitating efficient oxidative phosphorylation (OXPHOS) whilst regulating cytochrome c release from mitochondria. CL is especially enriched in the IMM and at sites of contact between the OMM and IMM. Disorders of protein misfolding, such as Alzheimer's and Parkinson's diseases, involve amyloidogenic peptides like amyloid‐β, tau and α‐synuclein, which form metastable toxic oligomeric species that interact with biological membranes. Electrophysiological studies have shown that these oligomers form ion‐conducting nanopores in membranes mimicking the IMM's phospholipid composition. Poration of mitochondrial membranes disrupts the ionic balance, causing osmotic swelling, loss of the voltage potential across the IMM, release of pro‐apoptogenic factors, and leads to cell death. The interaction between CL and amyloid oligomers appears to favour their membrane insertion and pore formation, directly implicating CL in amyloid toxicity. Additionally, pore formation in mitochondrial membranes is not limited to amyloid proteins and peptides; other biological peptides, as diverse as the pro‐apoptotic Bcl‐2 family members, gasdermin proteins, cobra venom cardiotoxins and bacterial pathogenic toxins, have all been described to punch holes in mitochondria, contributing to cell death processes. Collectively, these findings underscore the vulnerability of mitochondria and the involvement of CL in various pathogenic mechanisms, emphasizing the need for further research on targeting CL‐amyloid interactions to mitigate mitochondrial dysfunction. [ABSTRACT FROM AUTHOR]

Clostridium bacteria were already known to Hippocrates many years before Christ. The name of the Clostridium species is owed to the Polish microbiologist, Adam Prażmowski. It is now known that these Clostridium bacteria are widespread in the natural environment, and their presence in food products is a threat to human health and life. According to European Food Safety Authority (EFSA) reports, every year, there are poisonings or deaths due to ingestion of bacterial toxins, including those of the Clostridium spp. The strengthening of consumer health awareness has increased interest in consuming products with minimal processing in recent years, which has led to a need to develop new techniques to ensure the safety of microbiological food, including elimination of bacteria from the Clostridium genera. On the other hand, the high biochemical activity of Clostridium bacteria allows them to be used in the chemical, pharmaceutical, and medical industries. Awareness of microbiological food safety is very important for our health. Unfortunately, in 2022, an increase in infections with Clostridium bacteria found in food was recorded. Knowledge about food contamination should thus be widely disseminated. [ABSTRACT FROM AUTHOR]

Background: Hemolytic uremic syndrome (HUS) is an important cause of acute kidney injury in children. HUS is known as an acute disease followed by complete recovery, but patients may present with kidney abnormalities after long periods of time. This study evaluates the long-term outcome of Shiga toxin-producing Escherichia coli-associated HUS (STEC-HUS) in pediatric patients, 10 years after the acute phase of disease to identify risk factors for long-term sequelae. Methods: Over a 6-year period, 619 patients under 18 years of age with HUS (490 STEC-positive, 79%) were registered in Austria and Germany. Long-term follow-up data of 138 STEC-HUS-patients were available after 10 years for analysis. Results: A total of 66% (n = 91, 95% CI 0.57–0.73) of patients fully recovered showing no sequelae after 10 years. An additional 34% (n = 47, 95% CI 0.27–0.43) presented either with decreased glomerular filtration rate (24%), proteinuria (23%), hypertension (17%), or neurological symptoms (3%). Thirty had sequelae 1 year after STEC-HUS, and the rest presented abnormalities unprecedented at the 2-year (n = 2), 3-year (n = 3), 5-year (n = 3), or 10-year (n = 9) follow-up. A total of 17 patients (36.2%) without kidney abnormalities at the 1-year follow-up presented with either proteinuria, hypertension, or decreased eGFR in subsequent follow-up visits. Patients needing extracorporeal treatments during the acute phase were at higher risk of presenting symptoms after 10 years (p < 0.05). Conclusions: Patients with STEC-HUS should undergo regular follow-up, for a minimum of 10 years following their index presentation, due to the risk of long-term sequelae of their disease. An initial critical illness, marked by need of kidney replacement therapy or plasma treatment may help predict poor long-term outcome. [ABSTRACT FROM AUTHOR]

Bacterial ubiquitous Toxin-Antitoxin (TA) systems are considered to be important survival mechanisms during stress conditions. In regular environmental conditions, the antitoxin blocks the toxin, whereas during imbalanced conditions, the antitoxin concentration decreases, exposing the bacteria cell to a range of toxic events. The most evident consequence of this disequilibrium is cell growth arrest, which is the reason why TAs are generally described as active in the function of bacterial growth kinetics. Virulence-associated proteins B and C (VapBC) are a family of type II TA system, in which VapC is predicted to display the toxic ribonuclease activity while VapB counteracts this activity. Previously, using in silico data, we designated four VapBC TA modules in Leptospira interrogans serovar Copenhageni, the main etiological agent of human leptospirosis in Brazil. The present study aimed to obtain the proteins and functionally characterize the VapBC-1 module. The expression of the toxin gene vapC in E. coli did not decrease the cell growth rate in broth culture, as was expected to happen within active TA modules. However, interestingly, when the expression of the toxin was compared to that of the complexed toxin and antitoxin, cell viability was strongly affected, with a decrease of three orders of magnitude in colony forming unity (CFU). The assumption of the affinity between the toxin and the antitoxin was confirmed in vivo through the observation of their co-purification from cultivation of E. coli co-expressing vapB-vapC genes. RNAse activity assays showed that VapC-1 cleaves MS2 RNA and ribosomal RNA from L. interrogans. Our results indicate that the VapBC-1 module is a potentially functional TA system acting on targets that involve specific functions. It is very important to emphasize that the common attribution of the functionality of TA modules cannot be defined based merely on their ability to inhibit bacterial growth in a liquid medium. [ABSTRACT FROM AUTHOR]

Autophagy is a unique catabolic process that degrades irrelevant or damaged components in eukaryotic cells to maintain homeostasis and eliminate infections from pathogenesis. Pathogenic bacteria have developed many autophagy manipulation techniques that affect host immune responses and intracellular bacterial pathogens have evolved to avoid xenophagy. However, reducing its effectiveness as an innate immune response has not yet been elucidated. Bacterial pathogens cause autophagy in infected cells as a cell-autonomous defense mechanism to eliminate the pathogen. However, harmful bacteria have learned to control autophagy and defeat host defenses. Intracellular bacteria can stimulate and control autophagy, while others inhibit it to prevent xenophagy and lysosomal breakdown. This review evaluates the putative functions for xenophagy in regulating bacterial infection, emphasizing that successful pathogens have evolved strategies to disrupt or exploit this defense, reducing its efficiency in innate immunity. Instead, animal models show that autophagy-associated proteins influence bacterial pathogenicity outside of xenophagy. We also examine the consequences of the complex interaction between autophagy and bacterial pathogens in light of current efforts to modify autophagy and develop host-directed therapeutics to fight bacterial infections. Therefore, effective pathogens have evolved to subvert or exploit xenophagy, although autophagy-associated proteins can influence bacterial pathogenicity outside of xenophagy. Finally, this review implies how the complex interaction between autophagy and bacterial pathogens affects host-directed therapy for bacterial pathogenesis. [ABSTRACT FROM AUTHOR]

BACKGROUND: Transgenic crops producing insecticidal toxins from the bacterium Bacillus thuringiensis (Bt) have been used to manage insect pests for nearly 30 years. Dose of a Bt crop is key to assessing the risk of resistance evolution because it affects the heritability of resistance traits. Western corn rootworm (Diabrotica virgifera virgifera, LeConte), a major pest of maize, has evolved resistance to all commercially available Bt traits targeting it, and threatens resistance to future transgenic traits. Past research shows the dose of Bt maize targeting western corn rootworm can be confounded by larval density‐dependent mortality. We conducted a 2‐year field study at two locations to quantify larval density‐dependent mortality in Bt and non‐Bt maize. We used these results to calculate dose for our method and compared it to three previously published methods. Additionally, adult emergence and root injury were analyzed for predicting initial egg density. RESULTS: Increased pest density caused greater proportions of larvae to die in Bt maize than in non‐Bt maize. All methods for calculating dose produced values less than high‐dose, and stochastic variation had the greatest impact on dose at high and low pest densities. Our method for calculating dose did not produce values positively correlated with pest density while the three other methods did. CONCLUSION: To achieve the most accurate calculation of dose for transgenic maize targeting western corn rootworm, density‐dependent mortality should be taken into account for both transgenic and non‐transgenic maize and assessed at moderate pest densities. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Ticks, which are obligate blood‐feeding parasites, transmit a wide range of pathogens during their hematophagic process. Certain enzymes and macromolecules play a crucial role in inhibition of several tick physiological processes, including digestion and reproduction. In the present study, genes encoding type 2 cystatin were cloned and characterized from Haemaphysalis doenitzi, and the potential role of cystatin in tick control was further assessed. RESULTS: Two cystatin genes, HDcyst‐1 and HDcyst‐2, were successfully cloned from the tick H. doenitzi. Their open reading frames are 390 and 426 base pairs, and the number of coding amino acids are 129 and 141, respectively. In the midgut, salivary glands, Malpighian tubules and ovaries of ticks, the relative expression of HDcyst‐1 was higher in the midgut and Malpighian tubules, and HDcyst‐2 was higher in the salivary glands of H. doenitzi, respectively. Lipopolysaccharide (LPS) injection and low‐temperature stress elevated cystatin expression in ticks. Enzyme‐linked immunosorbent assay showed that both rHDcyst‐1 and rHDcyst‐2 protein vaccines increased antibody levels in immunized rabbits. A vaccination trial in rabbits infected with H. doenitzi showed that both recombinant cystatin proteins significantly reduced tick engorgement weights and egg mass weight, in particular, rHDcyst‐1 significantly prolonged tick engorgement time by 1 day and reduced egg hatching rates by 16.9%. In total, rHDcyst‐1 and rHDcyst‐2 protein vaccinations provided 64.1% and 51.8% protection to adult female ticks, respectively. CONCLUSION: This is the first report on the immunological characterization of the cystatin protein and sequencing of the cystatin gene in H. doenitzi. Cystatin proteins are promising antigens that have the potential to be used as vaccines for infestation of H. doenitzi control. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background Methods Results Conclusions Periodontitis is caused by a dysbiosis of oral bacteria resulting in alveolar bone destruction and teeth loss. The role of platelets in pathogenesis of periodontitis is a subject of research. The release of toxins from periodontitis‐associated bacteria may influence platelet function and contribute to the modulation of hemostatic or inflammatory responses. Therefore, we explored platelet function upon exposure to defined toxins: leukotoxin A from Aggregatibacter actinomycetemcomitans (LtxA), a synthetic version of the C14‐Tri‐LAN‐Gly peptide from Fusobacterium nucleatum (C14), and lipopolysaccharides from Porphyromonas gingivalis (LPS).Light transmission aggregometry was performed after the addition of toxins to platelet‐rich plasma in different doses. Flow cytometry was used to identify inhibitory effects of toxins by measuring phosphorylation of the vaso‐dilator‐stimulated phosphoprotein or to identify activating effects by the detection of CD62P expression. The release of chemokines derived from washed platelets was determined by immunoassays.Collagen‐induced threshold aggregation values were diminished upon incubation with LtxA and C14, accompanied with an increase of vaso‐dilator‐stimulated phosphoprotein (VASP) phosphorylation, indicating platelet inhibition. In contrast, LPS did not affect aggregation but slightly enhanced CD62P expression under co‐stimulation with low‐dose thrombin pointing to slight platelet activation. The three toxins did not relevantly influence the secretion of chemokines.Although weak, the investigated toxins differently influenced human platelet function. LtxA and C14 mediated inhibitory effects, whereas LPS contributed to a slight activation of platelets. Further analysis of specific cellular responses mediated by bacterial toxins may render novel targets and suggestions for the treatment of periodontitis. [ABSTRACT FROM AUTHOR]

The intracellular bacterial pathogen Legionella pneumophila modulates host cell functions by secreting multiple effectors with diverse biochemical activities. In particular, effectors of the SidE family interfere with host protein ubiquitination in a process that involves production of phosphoribosyl ubiquitin (PR-Ub). Here, we show that effector LnaB converts PR-Ub into ADP-ribosylated ubiquitin, which is further processed to ADP-ribose and functional ubiquitin by the (ADP-ribosyl)hydrolase MavL, thus maintaining ubiquitin homeostasis in infected cells. Upon being activated by actin, LnaB also undergoes self-AMPylation on tyrosine residues. The activity of LnaB requires a motif consisting of Ser, His and Glu (SHxxxE) present in a large family of toxins from diverse bacterial pathogens. Thus, our study sheds light on the mechanisms by which a pathogen maintains ubiquitin homeostasis and identifies a family of enzymes capable of protein AMPylation. The bacterial pathogen Legionella pneumophila secretes effectors that affect protein ubiquitination within host cells, involving production of phosphoribosyl ubiquitin (PR-Ub). Here, the authors identify additional effectors that convert PR-Ub back into functional ubiquitin, thus maintaining ubiquitin homeostasis in infected cells. [ABSTRACT FROM AUTHOR]

Infectious and foodborne diseases pose significant global threats, with devastating consequences in low- and middle-income countries. Ozone, derived from atmospheric oxygen, exerts antimicrobial effects against various microorganisms, and degrades fungal toxins, which were initially recognized in the healthcare and food industries. However, highly concentrated ozone gas can be detrimental to human health. In addition, ozonated water is unstable and has a short half-life. Therefore, ultrafine-bubble technology is expected to overcome these issues. Ultrafine bubbles, which are nanoscale entitles that exist in water for considerable durations, have previously demonstrated bactericidal effects against various bacterial species, including antibiotic-resistant strains. This present study investigated the effects of ozone ultrafine bubble water (OUFBW) on various bacterial toxins. This study revealed that OUFBW treatment abolished the toxicity of pneumolysin, a pneumococcal pore-forming toxin, and leukotoxin, a toxin that causes leukocyte injury. Silver staining confirmed the degradation of pneumolysin, leukotoxin, and staphylococcal enterotoxin A, which are potent gastrointestinal toxins, following OUFB treatment. In addition, OUFBW treatment significantly inhibited NF-κB activation by Pam3CSK4, a synthetic triacylated lipopeptide that activates Toll-like receptor 2. Additionally, OUFBW exerted bactericidal activity against Staphylococcus aureus, including an antibiotic-resistant strain, without displaying significant toxicity toward human neutrophils or erythrocytes. These results suggest that OUFBW not only sterilizes bacteria but also degrades bacterial toxins. [ABSTRACT FROM AUTHOR]

Sepsis is a potentially life-threatening condition triggered by pathogens such as bacteria and toxins. In clinical settings, hemoperfusion has been used as a therapeutic technique for the treatment of sepsis to remove pathogens, toxins and other inflammatory mediators from the bloodstream. However, the existing adsorption process of hemoperfusion is not specific to sepsis-related pathogens or toxins, resulting in unsatisfactory removal effectiveness and the lack of capture selectivity. Herein, we developed an ultrasound-responsive asymmetric polymeric microbowl coated with macrophage and red blood cell (RBC) membranes to selectively eliminate pathogens, toxins, and heavy metal ions from blood. Poly(glycidyl methacrylate) spherical microparticles were first synthesized and then eroded using dibutyl phthalate and styrene to form a microbowl structure. This asymmetric structure could provide acoustic radiation pressure gradients to realize orientation motion under non-invasive ultrasound fields with a velocity of 37.14 μm s−1 at 20 Vp–p, which could increase adsorption efficiency in physiological environments by fuel-free programable movements. In addition, the macrophage and RBC membrane coating endowed the microbowl with desired biocompatibility, enhanced blood circulation and the ability to selectively eliminate endotoxins, bacteria and heavy metal ions. Endotoxin removal assay showed that 92.80% of endotoxin was eliminated within 15 minutes. Owing to the affinity between the red blood cell membrane and heavy metal ions, the removal efficiency reached 92.75% and 93.91% for Pb2+ and Hg2+, respectively. Meanwhile, over 90% of S. aureus in the blood was eliminated owing to the selective recognition and adhesion of bacteria by macrophage membrane proteins. Overall, this work on ultrasound-responsive asymmetric polymeric microbowls provides a new insight to eliminate pathogens, toxins and heavy metal ions from the bloodstream for sepsis treatment. [ABSTRACT FROM AUTHOR]

1. Shiga toxin-producing Escherichia coli (STEC) strains are associated with disease outbreaks which cause a public health problem. The aim of this study was to determine the frequency of STEC strains, their virulence factors, phylogenetic groups and antimicrobial resistance profiles in broiler chickens.2. A total of 222 E.coli isolates were collected from the caecum of chickens intended to be slaughtered. Antibiotic susceptibility was tested against 21 antimicrobial agents and ESBL phenotype was assessed by double-disk synergy test. The presence of STEC virulence genes stx1, stx2,eaeA and ehxA was detected by PCR. The identification of STEC serogroups was realised by PCR amplification. Additive virulence genes, phylogenetic groups and integrons were examined among the STEC isolates.3. Out of 222 E.coli isolates, 72 (32%) were identified as STEC strains and the most predominant serogroups were O103, O145 and O157. Shiga toxin gene 1 (stx1) was found in 84.7% (61/72) of the STEC strains, and eae and stx2 were detected in 38.8% and 13.8%, respectively. The ESBL phenotype was documented in 48.6% (35/72) of isolates. Most of the isolates (90.3%) carried class 1 integron with the gene cassette encoding resistance to trimethoprim (dfrA) and streptomycin (aadA) in 31.9% of the isolates. Class 2 integron was identified in 36.1% of isolates.4. Broilers can be considered as a reservoir of STEC strains which have high virulence factors and integrons that might be transmitted to other chickens, environments and humans. It is important to undertake surveillance and efficient control measures in slaughterhouses and farms to control measures of STEC bacteria. [ABSTRACT FROM AUTHOR]

Bacterial toxins have received a great deal of attention in the development of cancer treatments. Parasporin-2 (PS2Aa1 or Mpp46Aa1) is a Bacillus thuringiensis parasporal protein that preferentially destroys human cancer cells while not harming normal cells, making it a promising anticancer treatment. With the efficient development and sustainable silver nanoparticles (AgNPs) synthesis technology, the biomedical use of AgNPs has expanded. This study presents the development of a novel nanotoxin composed of biosynthesized silver nanoparticles loaded with the N-terminal truncated PS2Aa1 toxin. MOEAgNPs were synthesized using a biological method, with Moringa oleifera leaf extract and maltose serving as reducing and capping agents. The phytochemicals present in M. oleifera leaf extract were identified by GC–MS analysis. MOEAgNPs were loaded with N-terminal truncated PS2Aa1 fused with maltose-binding protein (MBP-tPS2) to formulate PS2-MOEAgNPs. The PS2-MOEAgNPs were evaluated for size, stability, toxin loading efficacy, and cytotoxicity. PS2-MOEAgNPs demonstrated dose-dependent cytotoxicity against the T-cell leukemia MOLT-4 and Jurkat cell lines but had little effect on the Hs68 fibroblast or normal cell line. Altogether, the current study provides robust evidence that PS2-MOEAgNPs can efficiently inhibit the proliferation of T-cell leukemia cells, thereby suggesting their potential as an alternative to traditional anticancer treatments. [ABSTRACT FROM AUTHOR]

Anal swabs of 1-month-old Holstein calves with diarrhea were collected from an intensive cattle farm, and a highly pathogenic Escherichia coli strain was obtained by isolation and purification. To study the virulence and resistance genes of pathogenic E.coli that cause diarrhea in calves, a strain of E. coli E12 isolated from calf diarrhea samples was used as experimental material in this experiment, and the virulence of the E12 strain were identified by the mouse infection test, and the whole genome map of the E12 strain were obtained by whole-genome sequencing and analyzed for genome characterization. The results showed that the lethality of strain E12 was 100%, the total length of E12-encoded genes was 4,294,530 bp, Cluster of Orthologous Groups of proteins (COG) annotated to 4,194 functional genes, and the virulence genes of sequenced strain E12 were compared with the virulence genes of sequenced strain E12 from the Virulence Factors of Pathogenic Bacteria (VFDB), which contained a total of 366 virulence genes in sequenced strain E12. The analysis of virulence genes of E12 revealed a total of 52 virulence genes in the iron transferrin system, 56 virulence genes in the secretory system, 41 virulence genes in bacterial toxins, and a total of 217 virulence genes in the Adhesin and Invasins group. The antibiotic resistance genes of sequenced strain E12 were identified through the Antibiotic Resistance Genes Database (ARDB) and Comprehensive Antibiotic Research Database, and it was found that its chromosome and plasmid included a total of 127 antibiotic resistance genes in four classes, and that E12 carried 71 genes related to the antibiotic efflux pumps, 36 genes related to antibiotic inactivation, and 14 antibiotic target alteration and reduced penetration into antibiotics, and 6 antibiotic resistance genes, and the resistance phenotypes were consistent with the genotypes. The pathogenic E. coli that causes diarrhea in calves on this ranch contains a large number of virulence and resistance genes. The results provide a theoretical basis for the prevention and treatment of diarrhea and other diseases caused by E. coli disease. [ABSTRACT FROM AUTHOR]

Aim: This study aimed to evaluate the expression of tcdA, tcdB, and binary toxin genes (cdtA and cdtB) by Real-Time PCR and molecular typing of Clostridioides difficile isolated from patient diarrhea samples from Hamadan Hospitals, west of Iran. Background: The concentration of C. difficile toxins (CDTs) is associated with the severity of the disease and the mortality rate. Measuring CDT levels could provide a reliable and objective means of determining the severity of C. difficile infection (CDI). Methods: From November 2018 to September 2019, 130 diarrhea samples were collected from hospitalized patients in three hospitals in Hamadan. C. difficle isolates were detected by culture and PCR. The presence of the genes encoding the toxin was identified by PCR, whereas the measurement of toxin expression was conducted using a relative Real-Time PCR technique. Genetic linkage of the isolates was also assessed by Ribotyping and Repetitive Extragenic Palindromic (rep-PCR) methods. Results: Among 130 diarrhea samples, 16 (12.3%) were positive for C. difficile. Genes encoding cdtA and tcdB were detected in all isolates, and 8 (50%) and 6 (37.5%) isolates were positive for the cdtA and cdtB genes. Real-time PCR results showed different expression levels of the toxin genes. A significant increase in the expression of the tcdA gene was observed compared with the control strain (P<0.05). Besides, more expression of cdtA gene was observed in the strains compared with cdtB gene. Ribotyping and rep-PCR results showed high genetic diversity of C. difficile among hospitals investigated. Conclusion: We encountered toxigenic C. difficile strains with various toxin expression levels, ribotypes, and rep types based on the findings of this study. This indicated that various clones from various sources circulate in the hospitals and among patients. [ABSTRACT FROM AUTHOR]

Motivation ADP-ribosylation is a critical modification involved in regulating diverse cellular processes, including chromatin structure regulation, RNA transcription, and cell death. Bacterial ADP-ribosyltransferase toxins (bARTTs) serve as potent virulence factors that orchestrate the manipulation of host cell functions to facilitate bacterial pathogenesis. Despite their pivotal role, the bioinformatic identification of novel bARTTs poses a formidable challenge due to limited verified data and the inherent sequence diversity among bARTT members. Results We proposed a deep learning-based model, ARTNet, specifically engineered to predict bARTTs from bacterial genomes. Initially, we introduced an effective data augmentation method to address the issue of data scarcity in training ARTNet. Subsequently, we employed a data optimization strategy by utilizing ART-related domain subsequences instead of the primary full sequences, thereby significantly enhancing the performance of ARTNet. ARTNet achieved a Matthew's correlation coefficient (MCC) of 0.9351 and an F 1-score (macro) of 0.9666 on repeated independent test datasets, outperforming three other deep learning models and six traditional machine learning models in terms of time efficiency and accuracy. Furthermore, we empirically demonstrated the ability of ARTNet to predict novel bARTTs across domain superfamilies without sequence similarity. We anticipate that ARTNet will greatly facilitate the screening and identification of novel bARTTs from bacterial genomes. Availability and implementation ARTNet is publicly accessible at http://www.mgc.ac.cn/ARTNet/. The source code of ARTNet is freely available at https://github.com/zhengdd0422/ARTNet/. [ABSTRACT FROM AUTHOR]

The spread of multidrug-resistant Acinetobacter baumannii in hospitals and nursing homes poses serious healthcare challenges. Therefore, we aimed to isolate and characterize lytic bacteriophages targeting carbapenem-resistant Acinetobacter baumannii (CRAB). Of the 21 isolated A. baumannii phages, 11 exhibited potent lytic activities against clinical isolates of CRAB. Based on host spectrum and RAPD-PCR results, 11 phages were categorized into four groups. Three phages (vB_AbaP_W8, vB_AbaSi_W9, and vB_AbaSt_W16) were further characterized owing to their antibacterial efficacy, morphology, and whole-genome sequence and were found to lyse 37.93%, 89.66%, and 37.93%, respectively, of the 29 tested CRAB isolates. The lytic spectrum of phages varied depending on the multilocus sequence type (MLST) of the CRAB isolates. The three phages contained linear double-stranded DNA genomes, with sizes of 41,326–166,741 bp and GC contents of 34.4–35.6%. Genome-wide phylogenetic analysis and single gene-based tree construction revealed no correlation among the three phages. Moreover, no genes were associated with lysogeny, antibiotic resistance, or bacterial toxins. Therefore, the three novel phages represent potential candidates for phage therapy against CRAB infections. [ABSTRACT FROM AUTHOR]

The genome of Mycobacterium tuberculosis encodes for a large repertoire of toxin-antitoxin systems. In the present study, MenT3 and MenT4 toxins belonging to MenAT subfamily of TA systems have been functionally characterized. We demonstrate that ectopic expression of these toxins inhibits bacterial growth and this is rescued upon co-expression of their cognate antitoxins. Here, we show that simultaneous deletion of menT3 and menT4 results in enhanced susceptibility of M. tuberculosis upon exposure to oxidative stress and attenuated growth in guinea pigs and mice. We observed reduced expression of transcripts encoding for proteins that are essential or required for intracellular growth in mid-log phase cultures of ΔmenT4ΔT3 compared to parental strain. Further, the transcript levels of proteins involved in efficient bacterial clearance were increased in lung tissues of ΔmenT4ΔT3 infected mice relative to parental strain infected mice. We show that immunization of mice and guinea pigs with ΔmenT4ΔT3 confers significant protection against M. tuberculosis infection. Remarkably, immunization of mice with ΔmenT4ΔT3 results in increased antigen-specific TH1 bias and activated memory T cell response. We conclude that MenT3 and MenT4 are important for M. tuberculosis pathogenicity and strains lacking menT3 and menT4 have the potential to be explored further as vaccine candidates. Gosain et al.'s work aims to enhance understanding of the contribution of MenT3 and MenT4 toxins belonging to MenAT TA systems to the physiology and pathogenesis of Mycobacterium tuberculosis. The authors show that strains lacking these proteins is attenuated and confers protection in vivo. [ABSTRACT FROM AUTHOR]

Sugar beverages are discussed as critical in the development of metabolic endotoxemia. Here, employing a cross-over design study we assessed the effect of diluted cloudy apple juice (AJ), an iso-caloric and -sweetened placebo (P), or water (W) on post-prandial endotoxemia in healthy, normal weight adults. After obtaining fasting blood, 19 healthy men and women consumed 500 mL AJ, P, or W in a randomized order and blood was taken 120 and 180 min later. Caco-2 cells were incubated with the beverages. Markers of intestinal barrier function were assessed. The intake of P but not of AJ or W was associated with a significant increase in TLR2 ligands and bacterial endotoxin in serum after 120 min and 180 min, respectively. P but not AJ significantly increased bacterial toxin permeation in Caco-2 cells. Our results suggest that the effects of sugar-sweetened beverages on markers of intestinal barrier function markedly differ from those of fruit juices. [ABSTRACT FROM AUTHOR]

Trueperella pyogenes is an important opportunistic pathogenic bacterium widely distributed in the environment. Pyolysin (PLO) is a primary virulence factor of T. pyogenes and capable of lysing many different cells. PLO is a member of the cholesterol-dependent cytolysin (CDC) family of which the primary structure only presents a low level of homology with other members from 31% to 45%. By deeply studying PLO, we can understand the overall pathogenic mechanism of CDC family proteins. This study established a mouse muscle tissue model infected with recombinant PLO (rPLO) and its single-point mutations, rPLO N139K and rPLO F240A, and explored its mechanism of causing inflammatory damage. The inflammatory injury abilities of rPLO N139K and rPLO F240A are significantly reduced compared to rPLO. This study elaborated on the inflammatory mechanism of PLO by examining its unit point mutations in detail. Our data also provide a theoretical basis and practical significance for future research on toxins and bacteria. [ABSTRACT FROM AUTHOR]

Adenine diphosphate (ADP)‐ribosylation catalyzed by bacterial toxins is the addition of an ADP‐ribose moiety to specific amino acid residues in target proteins such as arginine, asparagine, glutamine, and histidine through 1,2‐cis(α)‐glycosidic bond formation. ADP‐ribosylation modifies host cell functions, altering normal cellular processes to facilitate their survival, and replication. Despite the development of click chemistry and solid‐phase peptide synthesis‐based approaches, the synthesis of structurally well‐defined naturally occurring N‐linked ADP‐ribosyl molecules remains challenging. Herein, we report a direct and α‐selective N‐ADP‐ribosylation using unprotected β‐ADP‐ribosyl azide and triphenylphosphine esters through traceless Staudinger ligation. The stereoselectivity of this protecting‐group‐free N‐ADP‐ribosylation was validated by enzymatic degradation experiment and high‐performance liquid chromatography, referencing synthetic standards. This method facilitated the facile and rapid synthesis of N‐ADP‐ribosyl acetamide, biotin, fluorescent dye, amino acids, and tripeptide with complete α‐selectivity and moderate yields (37–55 %). [ABSTRACT FROM AUTHOR]

Successful development of nucleic acid therapeutics requires effective manufacturing strategies tailored to the production and purification of RNA and DNA. Membrane processes can be used for initial clarification, removal of smaller host cell proteins and transcription factors, concentration and buffer exchange, and sterile filtration. Transmission of DNA and RNA in ultrafiltration is governed by both the effective size and elongational flexibility of the nucleic acids. Sterile filtration of DNA/RNA therapeutics can present unique challenges due to their large size and shear sensitivity. Nucleic acid therapeutics have the potential to revolutionize the biopharmaceutical industry, providing highly effective vaccines and novel treatments for cancers and genetic disorders. The successful commercialization of these therapeutics will require development of manufacturing strategies specifically tailored to the purification of nucleic acids. Membrane technologies already play a critical role in the downstream processing of nucleic acid therapeutics, ranging from clarification to concentration to selective purification. This review provides an overview of how membrane systems are currently used for nucleic acid purification, while highlighting areas of future need and opportunity, including adoption of membranes in continuous bioprocessing. [ABSTRACT FROM AUTHOR]

Background: Shiga toxin-producing E. coli-hemolytic uremic syndrome (STEC-HUS) is associated with high morbidity and relevant mortality. Previous small studies showed that volume expansion could improve the course and outcome of STEC-HUS. The aim of this single-center study was to evaluate the effect of volume expansion on the clinical course and outcome in STEC-HUS. Methods: Data of pediatric patients with STEC-HUS were analyzed retrospectively. Course and outcome of patients treated with volume expansion (VE) from 2019 to 2022 (n = 38) were compared to historical controls (HC) from 2009 to 2018 (n = 111). Results: Patients in the VE group had a significant relative median weight gain compared to HC (7.8% (3.4–11.3) vs. 1.2% (− 0.7–3.9), p < 0.0001) 48 h after admission. The need for dialysis was not reduced by VE (VE 21/38 (55.3%) vs. HC 64/111 (57.7%), p = 0.8). However, central nervous system involvement (impairment of consciousness, seizures, focal neurological deficits, and/or visual disturbances) was significantly reduced (VE 6/38 (15.8%) vs. HC 38/111 (34.2%), p = 0.039). None of the patients in the VE group died or developed chronic kidney disease (CKD) stage 5, whereas in the HC group, three patients died and three patients had CKD stage 5 at discharge. Conclusions: This study suggests that volume expansion may be associated with the mitigation of the acute course of STEC-HUS, especially severe neurological involvement and the development of CKD. Prospective trials should lead to standardized protocols for volume expansion in children with STEC-HUS. [ABSTRACT FROM AUTHOR]