Clostridium Sporogenes Research Articles

Clostridium sporogenes increases fat accumulation in mice by enhancing energy absorption and adipogenesis.

The Clostridia clusters have been implicated in energy metabolism, the specific species and underlying mechanisms remain unclear. This present study is the first to report Clostridium sporogenes is able to affect fat accumulation and glycolipid metabolism. We indicated that gavage of C. sporogenes promoted the adipogenesis and fat accumulation in mice by not only increasing the abundance of Clostridium bacteria but by also enhancing the metabolic absorption of carbohydrates and fatty acids significantly. Obviously, changes of gut microbiota caused by the C. sporogenes, especially the significant increase of Clostridium bacteria, contributed to the fat accumulation of mice. In addition, the enhancement of Clostridium genus bacteria remarkably improved the synthesis of hepatic pyruvate, acetyl-CoA, and triglyceride levels, as well as reduced the excretion of fecal carbohydrates, short-chain fatty acids, and free fatty acids remarkably. These findings will help us to understand the relationship of specific bacteria and host energy homeostasis.

Dietary fibre directs microbial tryptophan metabolism via metabolic interactions in the gut microbiota

Tryptophan is catabolized by gut microorganisms resulting in a wide range of metabolites implicated in both beneficial and adverse host effects. How gut microbial tryptophan metabolism is directed towards indole, associated with chronic kidney disease, or towards protective indolelactic acid (ILA) and indolepropionic acid (IPA) is unclear. Here we used in vitro culturing and animal experiments to assess gut microbial competition for tryptophan and the resulting metabolites in a controlled three-species defined community and in complex undefined human faecal communities. The generation of specific tryptophan-derived metabolites was not predominantly determined by the abundance of tryptophan-metabolizing bacteria, but rather by substrate-dependent regulation of specific metabolic pathways. Indole-producing Escherichia coli and ILA- and IPA-producing Clostridium sporogenes competed for tryptophan within the three-species community in vitro and in vivo. Importantly, fibre-degrading Bacteroides thetaiotaomicron affected this competition by cross-feeding monosaccharides to E. coli. This inhibited indole production through catabolite repression, thus making more tryptophan available to C. sporogenes, resulting in increased ILA and IPA production. The fibre-dependent reduction in indole was confirmed using human faecal cultures and faecal-microbiota-transplanted gnotobiotic mice. Our findings explain why consumption of fermentable fibres suppresses indole production but promotes the generation of other tryptophan metabolites associated with health benefits.

Clean labelling sodium nitrite at pilot scale: In-situ reduction of nitrate from plant sources and its effects on the overall quality and safety of restructured cooked ham

Growing health and environmental concerns have increased demand for all-natural products, with a focus on clean labelling. Sodium nitrite is the most widely used additive in the meat industry because it imparts the typical cured flavour and colour to meat products and, most importantly, their microbiological safety. However, due to health concerns, the European Commission is proposing revised regulations to reduce nitrate and nitrite levels in meat products. As a result, the meat industry is actively seeking alternatives. This study explored the production of four cooked hams utilising nitrate-rich vegetable sources combined with two different nitrate-reducing commercial food cultures, alongside a control ham prepared with sodium nitrite (150 ppm). Microbiological, physico-chemical (pH, water activity, nitrate and nitrite concentration, lipid profile, lipid oxidation) and sensory (texture and colour profile) characterisation of the products was carried out. Challenge tests for Listeria monocytogenes, Clostridium sporogenes and Clostridium perfringens have been performed to assess the growth of pathogens, if present in the products. Results revealed comparable microbiological and physico-chemical profiles across ham formulations, with minor differences observed in colour parameters for sample C. The sensory analysis showed that for the pilot ham formulations A and D, there were no significant differences in consumer perception compared to the control ham. In the challenge tests, L. monocytogenes levels were similar in both control and tested hams. There were no significant differences in C. sporogenes and C. perfringens counts at any temperature or between test and control samples. These results indicate that this technology has a potential future in the cured meat sector, as regulators mandate the reduction of added synthetic chemicals and consumers seek healthier and more natural ingredients in their daily diets.

Utilisation of Lactococcus lactis subsp. lactis (PY91K) and Lactiplantibacillus plantarum (Y48) to control Clostridium sporogenes during Turkish white cheese production and storage

SummaryThis study investigated the inhibition of Clostridium species, isolated from cheeses with late‐blowing defects, by lactic acid bacteria (LAB). Four batches of Turkish white cheeses were produced; control cheese, cheese sample containing Lactococcus lactis subsp. lactis (PY91K) and Lactiplantibacillus plantarum (Y48) as protective cultures (LAB), a cheese sample containing the protective culture and inoculated with Clostridium sporogenes spores (CL‐LAB) and finally a cheese sample containing only Cl. sporogenes spores (CL). White cheese's microbiological and physicochemical properties were also determined throughout the 90‐day storage period at 4 °C. Approximately 1 log reduction in Cl. sporogenes (ZMP‐1‐4) spores was observed in the LAB co‐inoculated Turkish white cheese samples.

Effect of indole 3-propionic acid from microbiota on the immunity of CD8+ T cell to improve chemotherapy of colorectal cancer.

e15194 Background: Sensitivity of chemotherapy is a great challenge to improve the treatment efficacy in patients with colorectal cancer (CRC). Increasing study has revealed the role of microbiota in the modulation of chemotherapy sensitivity. However, the mechanism how microbiota regulates the efficacy of 5-fluorouracil (5-FU) is far from clear. Methods: We used germ-free mice and antibiotic-treated mice to demonstrate the impact of the gut microbiota on 5-FU sensitivity. Metabolomics analysis of serum from patients with CRC or mice experiments were applied to identify the key metabolite, indole 3-propionic acid (IPA). Specific pattern of microbiota with capability to produce IPA was revealed by metagenomics analysis of the mice feces. Single-cell RNA (scRNA) sequencing was subsequently used and antibody blockade experiments as well as T cell adoptive transfer experiment were conducted to confirm the role of CD8+ T cells in 5-FU treatment. AHR KO mice model was used to reveal how IPA regulate the immunity of CD8+ T cells. Engineering Escherichia coli strain BL21 with capability to produce IPA was constructed to modulate the chemotherapy sensitivity. Results: Decreased sensitivity of 5-FU chemotherapy was observed in both germ-free mice and antibiotic-treated mice models. Accumulation of serum IPA was found in mice with vancomycin intervention and verified in CRC patient with chemotherapy resistance. Additionally, metagenomic analysis of mice feces revealed that Clostridium sporogenes capable of producing IPA, are crucial for 5-FU chemotherapy sensitivity. Supplementation with IPA or Clostridium sporogenes could obviously improve the sensitivity of 5-FU chemotherapy. Subsequently scRNA sequencing analysis of tumor tissue revealed a higher infiltration of CD8+ T cells after IPA intervention. The role of IPA-induced CD8+ T cells in 5-FU treatment was confirmed by antibody blockade experiments and T cell adoptive transfer experiment. Further, improved therapeutic sensitivity by IPA and the infiltration of CD8+ T cells were vanished in AHR KO mice model. Biosynthesis of IPA by engineering bacteria was found to enhance the sensitivity of 5-FU chemotherapy. Conclusions: Indole 3-propionic acid from microbiota enhances the immunity of CD8+ T cell via activation of AHR signaling pathway, thus providing potential therapeutic strategies to improve the efficacy of chemotherapy in colorectal cancer.

Isolation and identification of hydrocarbon degrading bacteria and fungi from waste engine oil impacted soil, their distribution frequency and hydrocarbon degradation capacity

The isolation and identification of hydrocarbon degrading bacteria and fungi from waste engine oil contaminated soil obtained from Mechanical Village, Uyo, Akwa Ibom State, their distribution frequency and hydrocarbon degradation capacity were investigated using standard method. The results revealed that Bacillus myocoides, Staphylococcus aureus, Listeria murrayi, Actinomycete viscosus, Clostridium sporogenes, Bacillus licheniformis, Corynebacterium ulcerans and Clostridium histolyticum were bacteria identified. Fungi identified were Fusarium oxysporum, Cryptococcus terreus, Penicillium notatum, Aspergillus fumigatus, Rhizopus stolonifer, Rhizopus oryzae and Rhodotorula mulcilaginosa. Their distribution frequency were B. myocoides (27.9 %), S. aureus (8.1 %), L. murrayi (9.9 %), A. viscosus (11.7 %), C. sporogenes (16.2 %), B. licheniformis (7.2%), C. ulcerans (12.6 %) and C. histolyticum (6.3 %) for bacteria. For the fungi, F. oxysporum (15.3 %), C. terreus (4.1%), P. notatum (20.4 %), A. fumigatus (11.2 %), R. stolonifer (10.2 %), R. oryzae (24.5%) and R. mulcilaginosa (14.3%). The efficiency of the microbial isolates to degrade waste engine oil from petrol and diesel driven vehicles as their major source of energy were found to vary among the microorganisms. C. sporogenes degraded waste engine oil from petrol driven vehicle with the highest efficiency (38.09%), whereas S. aureus demonstrated the least efficiency (19.28 %). C. histolyticum utilized waste oil from diesel vehicle with the highest efficiency (35.00%), while C. ulcerans was the least (17.31%). Among the fungi isolates, R. mulcilaginosa showed most degradation potential for spent oil from petrol driven vehicle (34.85 %) whereas C. terreus was the least (20.00 %). A. fumigatus exhibited highest degradation capacity for spent oil from diesel driven vehicle (29.73 %) while R. oryzae demonstrated the least potential (20.76 %). These results implied that microbial consortium could best be used for remediation of hydrocarbon contaminated soil.

Exploring Propolis as a Sustainable Bio-Preservative Agent to Control Foodborne Pathogens in Vacuum-Packed Cooked Ham.

The search for natural food additives makes propolis an exciting alternative due to its known antimicrobial activity. This work aims to investigate propolis' behavior as a nitrite substitute ingredient in cooked ham (a ready-to-eat product) when confronted with pathogenic microorganisms of food interest. The microbial evolution of Listeria monocytogenes, Staphylococcus aureus, Bacillus cereus, and Clostridium sporogenes inoculated at known doses was examined in different batches of cooked ham. The design of a challenge test according to their shelf life (45 days), pH values, and water activity allowed the determination of the mesophilic aerobic flora, psychotropic, and acid lactic bacteria viability. The test was completed with an organoleptic analysis of the samples, considering possible alterations in color and texture. The cooked ham formulation containing propolis instead of nitrites limited the potential growth (δ < 0.5 log10) of all the inoculated microorganisms until day 45, except for L. monocytogenes, which in turn exhibited a bacteriostatic effect between day 7 and 30 of the storage time. The sensory analysis revealed the consumer's acceptance of cooked ham batches including propolis as a natural additive. These findings suggest the functionality of propolis as a promising alternative to artificial preservatives for ensuring food safety and reducing the proliferation risk of foodborne pathogens in ready-to-eat products.

Multiplex genetic manipulations in Clostridium butyricum and Clostridium sporogenes to secrete recombinant antigen proteins for oral-spore vaccination

BackgroundClostridium spp. has demonstrated therapeutic potential in cancer treatment through intravenous or intratumoral administration. This approach has expanded to include non-pathogenic clostridia for the treatment of various diseases, underscoring the innovative concept of oral-spore vaccination using clostridia. Recent advancements in the field of synthetic biology have significantly enhanced the development of Clostridium-based bio-therapeutics. These advancements are particularly notable in the areas of efficient protein overexpression and secretion, which are crucial for the feasibility of oral vaccination strategies. Here, we present two examples of genetically engineered Clostridium candidates: one as an oral cancer vaccine and the other as an antiviral oral vaccine against SARS-CoV-2.ResultsUsing five validated promoters and a signal peptide derived from Clostridium sporogenes, a series of full-length NY-ESO-1/CTAG1, a promising cancer vaccine candidate, expression vectors were constructed and transformed into C. sporogenes and Clostridium butyricum. Western blotting analysis confirmed efficient expression and secretion of NY-ESO-1 in clostridia, with specific promoters leading to enhanced detection signals. Additionally, the fusion of a reported bacterial adjuvant to NY-ESO-1 for improved immune recognition led to the cloning difficulties in E. coli. The use of an AUU start codon successfully mitigated potential toxicity issues in E. coli, enabling the secretion of recombinant proteins in C. sporogenes and C. butyricum. We further demonstrate the successful replacement of PyrE loci with high-expression cassettes carrying NY-ESO-1 and adjuvant-fused NY-ESO-1, achieving plasmid-free clostridia capable of secreting the antigens. Lastly, the study successfully extends its multiplex genetic manipulations to engineer clostridia for the secretion of SARS-CoV-2-related Spike_S1 antigens.ConclusionsThis study successfully demonstrated that C. butyricum and C. sporogenes can produce the two recombinant antigen proteins (NY-ESO-1 and SARS-CoV-2-related Spike_S1 antigens) through genetic manipulations, utilizing the AUU start codon. This approach overcomes challenges in cloning difficult proteins in E. coli. These findings underscore the feasibility of harnessing commensal clostridia for antigen protein secretion, emphasizing the applicability of non-canonical translation initiation across diverse species with broad implications for medical or industrial biotechnology.

SpoIVA is an essential morphogenetic protein for the formation of heat- and lysozyme-resistant spores in Clostridium sporogenes NBRC 14293.

Clostridium sporogenes is an anaerobic spore-forming bacterium genetically related to Clostridium botulinum but lacks toxin genes. The sporulation mechanism and spore structures of anaerobic bacteria, including C. sporogenes, have not been comprehensively analyzed. Based on 16S rRNA gene analysis, it has been determined that C. sporogenes NBRC 14293 belongs to C. botulinum Group I. Moreover, SpoIVA is highly conserved in Bacillus and Clostridium species. Therefore, the aim of the present study is to investigate the mechanism of spore formation in C. sporogenes by performing a functional analysis of spoIVA encoding SpoIVA, a protein involved in the early development of the spore coat and cortex in Bacillus subtilis. Inactivation of spoIVA in C. sporogenes resulted in the loss of resistance of sporulating cells to lysozyme and heat treatments. Phase-contrast microscopy indicated that the inactivation of spoIVA caused the development of abnormal forespores and production of only a few immature spores. In the spoIVA mutant, abnormal swirl structures were detected in the mother cell using both phase-contrast and transmission electron microscopy. These swirls were stained with auramine O, pararosaniline hydrochloride, and 2-(4-aminophenyl)benzothiazole to examine the surface of mature spores of the wild-type strain. We found that the spore coat and exosporium proteins were misassembled and that they accumulated in the mother cells of the mutant. The results of this study indicate that SpoIVA is a spore morphogenetic protein, providing novel insights into spore morphogenesis in C. sporogenes.

Effects of field strength and frequency on inactivation of Clostridium sporogenes PA3679 spores during ohmic heating

The study explored the effects of electric field strength, temperature, and frequency on the inactivation of Clostridium sporogenes PA3679 spores (a surrogate of Clostridium botulinum) within buffer. The experiments were conducted at three different field strengths (30, 40, and 50 V/cm), temperatures (110, 120, and 130 °C), and frequencies (60, 1000, and 5000 Hz). Ohmic heating resulted in significantly greater reduction of C. sporogenes compared to conventional heating. Electric field strength significantly influenced spore inactivation. It was found that lower frequencies led to quicker rates of inactivation. Given that high field strengths have dual benefits of increasing both heating and spore kill rate, the possibility exists to process foods to sterility without a hold. This is expected to result in improved product quality, reduced process times and increased efficiency.

Antimicrobial effects of cannabidiol on select agriculturally important Clostridia

Amino acid-fermenting Clostridia have undesirable effects in agricultural systems, which can be mitigated by antibiotics, but resistance necessitates alternatives. Here, we demonstrate the efficacy of cannabidiol on growth and ammonia inhibition of five agriculturally relevant Clostridia: Clostridium sporogenes, Peptostreptococcus spp., Clostridioides difficile, Acetoanaerobium sticklandii, and Clostridium aminophilum.

Controlling Clostridium sporogenes spoilage of “requeijão cremoso” processed cheese: Modeling the growth/no-growth probability as a function of pH, sodium chloride and nisin

Predictive models were developed to assess the growth response of Clostridium sporogenes in “requeijão cremoso” processed cheese, as affected by pH and sodium chloride and nisin concentrations. A complete factorial design was performed using different formulations: pH (5.2, 5.6, and 6.0), sodium chloride (0.5, 0.75, 1.0, 1.25, and 1.5%), and nisin (0.0, 5.0, 7.5, 10.0 and 12.5 mg/kg), totalizing 75 conditions. Packs with 150 g of “requeijão cremoso” were inoculated with 103 spores/g following storage at 10 °C for up to 60 days. The counts of C. sporogenes were performed on day zero and at the end of storage after a heat shock (80 °C for 12 min). The formulations that allowed an increase in the population >1 log CFU/g were assigned the value of 1 (growth), and the formulations in which the increase was <l log CFU/g were assigned 0 (no growth). Overall, the growth of C. sporogenes was affected by pH, salt concentration and nisin, e.g. at pH 5.2 the growth/no growth limit is 1.25% salt and no nisin, at pH 5.6 this limit is reduced to 0.75% salt, while at pH 6.0 only the effect of pH was sufficient to inhibit C. sporogenes even in the absence of salt and nisin. All isolated parameters and their combinations significantly affected spore germination, indicating that the model generated significantly contributes to the optimization of the processing and mitigation of the microbiological spoilage of “requeijão cremoso” processed cheese by Clostridia.

Microbial metabolite enhances immunotherapy efficacy by modulating T cell stemness in pan-cancer

The immune checkpoint blockade (ICB) response in human cancers is closely linked to the gut microbiota. Here, we report that the abundance of commensal Lactobacillus johnsonii is positively correlated with the responsiveness of ICB. Supplementation with Lactobacillus johnsonii or tryptophan-derived metabolite indole-3-propionic acid (IPA) enhances the efficacy of CD8+ Tcell-mediated αPD-1 immunotherapy. Mechanistically, Lactobacillus johnsonii collaborates with Clostridium sporogenes to produce IPA. IPA modulates the stemness program of CD8+ Tcells and facilitates the generation of progenitor exhausted CD8+ Tcells (Tpex) by increasing H3K27 acetylation at the super-enhancer region of Tcf7. IPA improves ICB responsiveness at the pan-cancer level, including melanoma, breast cancer, and colorectal cancer. Collectively, our findings identify a microbial metabolite-immune regulatory pathway and suggest a potential microbial-based adjuvant approach to improve the responsiveness of immunotherapy.

Emulsified and Nanoemulsified Essential Oils in the Control of Clostridium botulinum and Clostridium sporogenes in Mortadella.

Clostridium botulinum is a foodborne pathogen responsible for severe neuroparalytic disease associated with the ingestion of pre-formed toxin in food, with processed meats and canned foods being the most affected. Control of this pathogen in meat products is carried out using the preservative sodium nitrite (NaNO2), which in food, under certain conditions, such as thermal processing and storage, can form carcinogenic compounds. Therefore, the objective was to use nanoemulsified essential oils (EOs) as natural antimicrobial agents, with the aim of reducing the dose of NaNO2 applied in mortadella. The antimicrobial activity of nanoemulsions prepared with mixtures of EOs of garlic, clove, pink pepper, and black pepper was evaluated on endospores and vegetative cells of C. botulinum and Clostridium sporogenes (surrogate model) inoculated in mortadella prepared with 50 parts per million NaNO2. The effects on the technological (pH, water activity, and color) and sensory characteristics of the product were also evaluated. The combinations of EOs and their nanoemulsions showed sporicidal effects on the endospores of both tested microorganisms, with no counts observed from the 10th day of analysis. Furthermore, bacteriostatic effects on the studied microorganisms were observed. Regarding the technological and sensorial characteristics of the product, the addition of the combined EOs had a negative impact on the color of the mortadella and on the flavor/aroma. Despite the strong commercial appeal of adding natural preservatives to foods, the effects on flavor and color must be considered. Given the importance of controlling C. botulinum in this type of product, as well as the reduction in the amount of NaNO2 used, this combination of EOs represents a promising antimicrobial alternative to this preservative, encouraging further research in this direction.

Sterilization of Human Amniotic Membrane Using an Ozone Hydrodynamic System.

Human amniotic membrane (hAM) is an important biomaterial for Tissue Engineering, due to its great regenerative properties and potential use as a scaffold. The most used procedure to sterilize biomaterials is gamma-irradiation, but this method can affect several properties, causing damage to the structure and reducing the growth factors. The present work evaluated the efficiency of a new method based on ozonated dynamic water for hAM sterilization. HAM fragments were experimentally contaminated with Staphylococcus aureus, Escherichia coli, Candida albicans, Staphylococcus epidermidis, and Clostridium sporogenes (106CFU/mL) and submitted to sterilization process for 5, 10 and 15min. The analyses did not reveal microbial activity after 10min for S. aureus and C. sporogenes and after 15min for E. coli and S. epidermidis. The microbial activity of C. albicans was reduced with the exposure time increase, but the evaluated time was insufficient for complete sterilization. The depyrogenation process was investigated for different ozonation times (15, 20, 25, 30, and 35min) to evaluate the ozone sterilization potential and presented promising results after 35min. The ozone effect on hAM structure was evaluated by histological analysis. A decrease in epithelium average thickness was observed with the exposure time increase. Furthermore, some damage in the epithelium was observed when hAM was exposed for 10 and 15min. It can indicate that ozone, besides being effective in sterilization, could promote the hAM sample's de-epithelization, becoming a possible new method for removing the epithelial layer to use hAM as a scaffold.

Mining the Metabolic Capacity of Clostridium sporogenes Aided by Machine Learning.

Anaerobes dominate the microbiota of the gastrointestinal (GI) tract, where a significant portion of small molecules can be degraded or modified. However, the enormous metabolic capacity of gut anaerobes remains largely elusive in contrast to aerobic bacteria, mainly due to the requirement of sophisticated laboratory settings. In this study, we employed an in silico machine learning platform, MoleculeX, to predict the metabolic capacity of a gut anaerobe, Clostridium sporogenes, against small molecules. Experiments revealed that among the top seven candidates predicted as unstable, six indeed exhibited instability in C. sporogenes culture. We further identified several metabolites resulting from the supplementation of everolimus in the bacterial culture for the first time. By utilizing bioinformatics and in vitro biochemical assays, we successfully identified an enzyme encoded in the genome of C. sporogenes responsible for everolimus transformation. Our framework thus can potentially facilitate future understanding of small molecules metabolism in the gut, further improve patient care through personalized medicine, and guide the development of new small molecule drugs and therapeutic approaches.

Mining the Metabolic Capacity of Clostridium sporogenes Aided by Machine Learning

AbstractAnaerobes dominate the microbiota of the gastrointestinal (GI) tract, where a significant portion of small molecules can be degraded or modified. However, the enormous metabolic capacity of gut anaerobes remains largely elusive in contrast to aerobic bacteria, mainly due to the requirement of sophisticated laboratory settings. In this study, we employed an in silico machine learning platform, MoleculeX, to predict the metabolic capacity of a gut anaerobe, Clostridium sporogenes, against small molecules. Experiments revealed that among the top seven candidates predicted as unstable, six indeed exhibited instability in C. sporogenes culture. We further identified several metabolites resulting from the supplementation of everolimus in the bacterial culture for the first time. By utilizing bioinformatics and in vitro biochemical assays, we successfully identified an enzyme encoded in the genome of C. sporogenes responsible for everolimus transformation. Our framework thus can potentially facilitate future understanding of small molecules metabolism in the gut, further improve patient care through personalized medicine, and guide the development of new small molecule drugs and therapeutic approaches.

A188 ENHANCED MICROBIAL TRYPTOPHAN METABOLISM ACTIVATES THE ARYL HYDROCARBON RECEPTOR AND AMELIORATES INTESTINAL INFLAMMATION

Abstract Background Intestinal microbiota, diet, and the immune system have been proposed to contribute to the development of inflammatory bowel diseases (IBD). The aryl hydrocarbon receptor (AhR) is a critical regulator of intestinal immunity and mucosal barrier homeostasis that is activated by agonists such as host and microbial tryptophan metabolites. IBD patients have altered microbiota and reduced AhR agonists in intestinal content resulting in downregulation of AhR. Our recent findings indicate that mice harbouring microbiota with impaired tryptophan metabolism and AhR agonist production develop more severe inflammation during colitis. Aims To study the influence of diet-microbe interventions on AhR activation and intestinal inflammation in mice with impaired microbial tryptophan metabolism. Methods Germ-free C57BL/6 mice from McMaster’s Axenic Gnotobiotic Unit were colonized with cecal content of mice harbouring reduced microbiota with impaired tryptophan metabolism with and without tryptophan metabolizing Clostridium sporogenes. Following three weeks of microbial stabilization, mice were provided a high tryptophan (HT) diet or a low tryptophan (LT) diet as a control. Experimental colitis was induced using dextran sulfate sodium in drinking water (DSS; 2.5% w/v). Briefly, DSS was provided ad libitum for five days, followed by two days of recovery before tissue collection. Activation of AhR was measured in stool and C. sporogenes cultures using an in vitro AhR luciferase reporter assay. AhR agonists were quantified by capillary-electrophoresis-mass spectrometry. Colonic expression of AhR pathway genes was evaluated by RT-qPCR. Susceptibility to colitis was assessed by histologic analysis of distal colon sections, fecal lipocalin-2, weight loss, and clinical scores. Inflammatory gene transcripts were quantified in colon tissue by Nanostring. Results C. sporogenes efficiently produces AhR agonists in vitro and in vivo. In mice with impaired tryptophan metabolism, the HT diet increased AhR agonists in intestinal content and colonic AhR pathway gene expression, which was further enhanced in mice colonized with C. sporogenes. Compared to mice fed LT and HT diets, mice colonized with C. sporogenes and fed HT were most protected from weight loss, tissue damage, and immune cell infiltration. Conclusions These findings highlight the potential of tryptophan-rich diets and targeted microbe interventions as a novel approach to enhance AhR activation and mitigate inflammation during colitis. Consequently, exploring methods to improve tryptophan metabolism through diet and manipulation of the microbiota could be a promising therapeutic avenue for IBD patients with impaired AhR activation. Funding Agencies CCC, CIHR

Antitumor impact of Clostridium sporogenes endospores against diethyl nitrose amine induce hepatocellular carcinoma in rats

Antitumor impact of Clostridium sporogenes endospores against diethyl nitrose amine induce hepatocellular carcinoma in rats

Clostridium Bacteria: Harnessing Tumour Necrosis for Targeted Gene Delivery.

Necrosis is a common feature of solid tumours that offers a unique opportunity for targeted cancer therapy as it is absent from normal healthy tissues. Tumour necrosis provides an ideal environment for germination of the anaerobic bacterium Clostridium from endospores, resulting in tumour-specific colonisation. Two main species, Clostridium novyi-NT and Clostridium sporogenes, are at the forefront of this therapy, showing promise in preclinical models. However, anti-tumour activity is modest when used as a single agent, encouraging development of Clostridium as a tumour-selective gene delivery system. Various methods, such as allele-coupled exchange and CRISPR-cas9 technology, can facilitate the genetic modification of Clostridium, allowing chromosomal integration of transgenes to ensure long-term stability of expression. Strains of Clostridium can be engineered to express prodrug-activating enzymes, resulting in the generation of active drug selectively in the tumour microenvironment (a concept termed Clostridium-directed enzyme prodrug therapy). More recently, Clostridium strains have been investigated in the context of cancer immunotherapy, either in combination with immune checkpoint inhibitors or with engineered strains expressing immunomodulatory molecules such as IL-2 and TNF-α. Localised expression of these molecules using tumour-targeting Clostridium strains has the potential to improve delivery and reduce systemic toxicity. In summary, Clostridium species represent a promising platform for cancer therapy, with potential for localised gene delivery and immunomodulation selectively within the tumour microenvironment. The ongoing clinical progress being made with C. novyi-NT, in addition to developments in genetic modification techniques and non-invasive imaging capabilities, are expected to further progress Clostridium as an option for cancer treatment.