Live Bacteria Research Articles

Peripherally-restricted recurrent infection by engineered E. coli strain modulates hippocampal proteome promoting memory impairments in a rat model

Commensal bacteria that breach endothelial barrier has been reported to induce low grade chronic inflammation producing disease symptoms in major peripheral tissues. In this study, we investigated the role of genetically modified cellular invasive form of commensal E. coli K12 (SK3842) in cognitive impairment. Low-grade systemic infection model was developed using recurring peripheral inoculation of live bacteria in Wistar rats. To examine memory parameters, Novel object recognition test and Radial arm maze test were performed. Differential protein expression profiling of rat hippocampus was carried out using LC-MS/MS and subsequently quantified using SWATH. HBA1/2, NEFH, PFN1 and ATP5d were chosen for validation using quantitative RT-PCR. Results showed drastic decline in Recognition memory of the SK3842 infected rats. Reference and Working Memory of the infected group were also significantly reduced in comparison to control group. Proteome analysis using LC-MS/MS coupled with SWATH revealed differential expression of key proteins that are crucial for the maintenance of various neurological functions. Moreover, expression of NEFH and PFN1transcripts were found to be in line with the proteomics data. Protein interaction network of these validated proteins generated by STRING database converged to RhoA protein. Thus, the present study establishes an association between peripheral infection of a hippocampal protein network dysregulation and overall memory decline.

The Antifungal Activity of Chitosan Nanoparticle-Incorporated Probiotics Against Oral Candidiasis.

Candida species, especially Candida albicans, cause oral candidiasis, also known as oral thrush. It affects the elderly, newborns, patients under antibiotics, chemotherapeutic agents, and patients with weaker immune systems. Although successful, traditional antifungal medications are available, they may have negative effects and do not prevent recurrence. Conventional antifungal medications have a restricted range of effectiveness; hence, the need for a novel antifungal agent arises. Chitosan, a natural polymer made from chitin found in crustaceans, kills fungal cells by damaging membranes. Excellent biocompatibility and biodegradability make it a promising medical material. Probiotics, live bacteria, compete with pathogenic microbes for adhesion sites and nutrients, produce antimicrobials such as lactic acid, hydrogen peroxide, and bacteriocins, and modulate the host's immunological response. Adding probiotics to chitosan nanoparticles (CSNPs) boosts their antifungal activity against Candida species and increases their stability and transport to the infection site. The antifungal activity was evaluated through in vitro experiments utilizing Candida strains that are significant to oral candidiasis. Different concentrations of CSNPs and formulations loaded with probiotics were examined to assess their effectiveness. The antifungal properties were assessed using microbiological assays, specifically agar diffusion and minimum inhibitory concentration (MIC). The study demonstrated a notable fungicidal impact of CSNPs combined with probiotics against oral candidiasis. Furthermore, the MICvalues were lower for the probiotic-loaded CSNPs than for chitosan alone or probiotics alone. The combination of CSNPs and probiotics shows potential in effectively combating oral candidiasis by inhibiting fungal growth. This novel method offers a promising strategy for creating therapeutic treatments for oral candidiasis by utilizing the combined benefits of chitosan and probiotics to combat fungal infections effectively.

NIR responsive nanosystem based on upconversion nanoparticle-engineered bacteria for immune/photodynamic combined therapy with bacteria self-clearing capability

Biological engineering bacteria hold great promise in tumor therapy due to their targeted delivery, tumor penetration, and tumor-specific activation capabilities. However, the use of live bacteria raises safety concerns, as they can potentially cause infections or adverse immune responses in patients. Additionally, most biological engineering bacteria are only responsive to blue light, which has limited penetration depth within biological tissues. To address these limitations, we have developed a nanoplatform that combines dual-emission upconversion nanoparticles (referred to as DDUCNPs), which can realize dual-wavelength emission under dual-wavelength excitation, with biological engineering bacteria for tumor treatment and the self-clearance of biological engineering bacteria after therapy in the near-infrared (NIR) window. This design allows us to utilize 980 nm light, which is converted to blue light by the DDUCNPs, to activate the bacteria and promote the controlled release of tumor necrosis factor-alpha (TNF-α) for precise tumor ablation. Subsequently, we employ 808 nm excitation to achieve light conversion into the red light, thereby activating photosensitizer molecules and generating singlet oxygen (ROS) for in vivo clearance of the bacteria involved in the treatment. Simultaneously, the generated ROS also undergoes photodynamic therapy (PDT) on the tumor to enhance the therapeutic effect. By combining these elements on a single platform, our system achieves the activation and self-clearance of biological engineering bacteria in the NIR window, effectively enabling tumor treatment. This approach overcomes the limitations of blue light penetration and addresses safety concerns associated with live bacteria, offering a promising strategy for precise and controlled tumor therapy.

Macrophage-Activated Products of Lacticaseibacillus paracasei N1115 Promote the Development of Primary Hippocampal Neurons

To make a preliminary investigation of the effect of the immune pathway mediated by live Lacticaseibacillus paracasei N1115 on the development of primary hippocampal neurons cultured in vitro. Live Lacticaseibacillus paracasei N1115 suspension of an appropriate concentration was used as the experimental group. Peptidoglycan (PGN) and lipopolysaccharide (LPS) were used as positive controls, and RPMI1640 medium served as the blank control. These were co-cultured with RAW264.7 cells to obtain the co-culture mediums and the total cellular RNA, and to measure the expression and secretion of cytokines. After centrifugation, the supernatants were co-cultured with primary hippocampal neurons at appropriate ratios. The co-culture mediums were collected, and the total cellular RNA was extracted to measure the expression of genes related to synaptic development in neurons. Following immunofluorescence staining of the primary hippocampal neurons, the presynaptic and presynaptic membrane-associated proteins, including synaptophysin (SYP) and the postsynaptic density protein 95 (PSD95), and neuronal cell maturation markers, including microtubule-associated protein 2 (MAP-2), and doublecortin (DCX) were quantitatively analyzed. Additionally, the morphological development of the neurons were measured. Compared with the blank control, the mRNA expression levels of interleukin (IL)-6 and tumor necrosis factor- α (TNF-α) increased by 7471% and 926%, respectively, after the RAW264.7 cells were treated with live Lacticaseibacillus paracasei N1115, while their secretion levels increased by 184.16 pg/mL and 12320.76 pg/mL, respectively, all showing statistically significant differences (P<0.05). The activation ability of N1115 live bacteria was stronger than that of PGN but weaker than that of LPS, showing statistically significant differences (P<0.05). Compared with the blank control, following the intervention with the supernatant from the co-culture of N1115 live bacteria and RAW264.7 cells, the viability of primary hippocampal neurons in the 10% supernatant intervention group increased by 19.25%, showing statistically significant differences (P<0.05), and the mRNA expression of SYP and PSD95 increased by 137% and 159%, respectively, showing statistically significant differences (P<0.05). The total neurite length (489.88 μm) of the neurons of the group intervened with the supernatant of N1115 live bacteria was increased compared to that of the blank control group (381.51 μm), and the cell body area (2092.22 μm2), maximum neurite length (184.78 μm), total neurite length, average neurite length (108.38 μm), and branching points (4.84 s) were higher than those in the two positive control groups, showing statistically significant differences (P<0.05). Lacticaseibacillus paracasei N1115 can significantly activate the immune regulatory function of macrophages, thereby promoting the morphological development and synaptic function of nerve cells.

Phage LysSA163-CBD mediated specific recognition coupled with ATP bioluminescence for the sensitive detection of viable Staphylococcus aureus in food matrices

BackgroundStaphylococcus aureus is a significant foodborne pathogen, commonly detected in milk and meat products. Conventional detection methods have limited sensitivity and specificity, which are time-consuming and susceptible to background interference from complex samples, and cannot effectively distinguish live and dead bacteria. ResultsHerein, we developed a novel adenosine triphosphate (ATP) bioluminescence method coupled with magnetic separation, which is based on phage-encoded endolysin LysSA163-CBD (CBD 163) for rapid and specific detection of viable Staphylococcus aureus. The expressed protein (CBD 163) was derived from the phage LSA2301 and was successfully expressed in Escherichia coli BL21 following an induction period of 4 h at 37 °C, with a molecular weight approximating 40 kDa. The optimal conditions for CBD-magnetic beads (cMBs) to capture S. aureus cells were determined to be 100 μL/mL cMBs at 25 °C for 30 min. The viable S. aureus cells were disrupted by the Cetyl trimethyl ammonium bromide (CTAB) to release intracellular ATP. Then, the ATP reacted with the firefly luciferase and D-Luciferin-based bioluminescence (BL) reagents solution to generate intensive BL signal. The CBD-magnetic separation-ATP bioluminescence (cMS-BL) assay was able to quickly detect viable S. aureus via ATP bioluminescence in 45 min, with a detection range from 5 × 103 to 5 × 107 CFU/mL and limit of detection (LOD) of 190 CFU/mL. Additionally, the cMS-BL method exhibited high specificity and anti-interference ability, which has been successfully applied to quantify S. aureus cells in crayfish-tail, chicken, and skim milk. Significance and noveltyThese results demonstrate the potential of CBD 163 as a versatile and robust biorecognition element for rapid and specific detection of viable S. aureus in food matrices. The proposed phage-derived bacteria-binding proteins-based protocol for BL detection shows various advantages, including high sensitivity, simple operation, and the capability to distinguish live bacteria, providing a strategy for designing high-quality biorecognition element toward foodborne pathogens.

PSV-12 Evaluating the effect of lyoprotectants in preserving community structure and bacterial viability in the lyophilized fecal community of pigs

Abstract Fecal microbiota transplantation (FMT) stands as a potential method for enhancing pig health. FMT has progressed from the basic delivery of fresh stool, to lyophilized preparations which is beneficial for sample storage, but can damage bacterial cells. This has necessitated the need for lyoprotectants to preserve bacterial viability. However, the ideal lyoprotectant for retaining community structure and viability remains unclear. Furthermore, DNA-based microbial profiling methods such as 16S rRNA and metagenomics sequencing do not distinguish live and dead bacteria, prompting the need for other methods of distinguishing live and dead members of the bacterial community after lyophilization. PMA-seq (propidium monoazide treatment followed by 16S rRNA gene amplicon sequencing) has been shown to differentiate between live and dead bacteria in microbial communities. To refine FMT in pigs, we sought to ascertain the impact of four lyoprotectants on bacterial viability and fecal microbiome structure. Fecal samples from six pigs were treated with mannitol, maltodextrin, trehalose, maltodextrin-trehalose mix (2.5% each) as lyoprotectants or left untreated. Lyophilized fecal samples underwent PMA treatment prior to 16S rRNA sequencing to capture the active community, and total and viable bacterial cells number were quantified. One-way ANOVA was used to analyze total and viable bacterial cells, and richness, while PERMANOVA was used to compare beta diversity. Results revealed no initial differences in total, viable bacteria, or community structure (P &amp;gt; 0.05). However, untreated, and mannitol-treated groups showed significantly reduced total and viable bacterial cells post-lyophilization (P &amp;lt; 0.01), unlike the other lyoprotectants (P &amp;gt; 0.05). Mannitol and the untreated group also displayed decreased richness and beta diversity shifts (P &amp;lt; 0.05). Overall, lyophilization with mannitol or no lyoprotectant notably impacted pig fecal microbiota community structure, while maltodextrin, trehalose, and maltodextrin-trehalose effectively preserved bacterial viability and structure.

123 Effects of a Saccharomyces cerevisiae based direct-fed microbial on performance, health, and rumen bacterial community of newly weaned beef steers during a 56-d receiving period

Abstract We examined the effects of a blend of Saccharomyces cerevisiae, multiple live probiotic bacteria and their fermentation products on performance, health, and the ruminal bacterial community of newly weaned beef steers during a 56-d receiving period. Newly weaned Angus crossbred steers [n = 40; 221 ± 25.6 kg body weight (BW); 180 ± 17 d of age] were stratified by BW into four pens (10 steers per pen) such that each pen had a similar average BW at the beginning of the experiment. The pens were randomly assigned to receive a corn silage basal diet (CON; n = 20) or the basal diet supplemented with 9 g·steer⁻¹·d⁻¹of PRO feed additive (PRO; n = 20). The PRO additive is a blend of Saccharomyces cerevisiae and the fermentation products of Enterococcus faecium, Bacillus licheniformis, Bacillus subtilis, Lactobacillus animalis, Propionibacterium freudenreichii. The DMI and water consumed were monitored using the GrowSafe intake nodes and custom flow meters, respectively. Body weights were recorded weekly to calculate average daily gain (ADG). Before morning feeding, 10 mL of blood was taken from each steer on d 0 to 7, and thereafter weekly for analyses of immune cells, plasma glucose and NEFAs. On d 56, rumen fluid samples (200 mL each) were collected from all the steers for microbiome analysis. Over the 56-d receiving period, the supplemental PRO had no effects on DMI, water intake, or ADG. However, compared with CON, beef steers fed supplemental PRO tended to have greater ADG (P = 0.08) and BW (P = 0.07) during the first 14 d of the study. There was a treatment × day interaction (P ≤ 0.05) for WBC, neutrophils and monocytes over the 56 d such that beef steers fed supplemental PRO had decreased blood concentrations on certain days during the first 7 d after weaning, indicating reduced inflammation or stress response. The results of the rumen microbiome analysis revealed that the relative abundance of complex fiber degrading or obligate proton-reducing bacterial genera such as Bacteroides, Ruminococcus gauvreauii group, Desulfovibrio, Syntrophococcus, and Acetitomaculum were greater (P ≤ 0.05) in beef steers fed supplemental PRO compared with CON. This study demonstrated that dietary supplementation of PRO improved the growth performance, reduced stress or inflammatory response during the initial days after weaning and altered the ruminal bacterial community towards increased relative abundance of bacterial genera associated with improved rumen function.

Glycoengineering with neuraminic acid analogs to label lipooligosaccharides and detect native sialyltransferase activity in gram-negative bacteria.

Lipooligosaccharides (LOS) are the most abundant cell surface glycoconjugates on the outer membrane of Gram-negative bacteria. They play important roles in host-microbe interactions. Certain Gram-negative pathogenic bacteria cap their LOS with the sialic acid, N-acetylneuraminic acid (Neu5Ac), to mimic host glycans that among others protects these bacteria from recognition by the hosts immune system. This process of molecular mimicry is not fully understood and remains under investigated. To explore the functional role of sialic acid-capped lipooligosaccharides (LOS) at the molecular level, it is important to have tools readily available for the detection and manipulation of both Neu5Ac on glycoconjugates and the involved sialyltransferases, preferably in live bacteria. We and others have shown that the native sialyltransferases of some Gram-negative bacteria can incorporate extracellular unnatural sialic acid nucleotides onto their LOS. We here report on the expanded use of native bacterial sialyltransferases to incorporate neuraminic acids analogs with a reporter group into the LOS of a variety of Gram-negative bacteria. We show that this approach offers a quick strategy to screen bacteria for the expression of functional sialyltransferases and the ability to use exogenous CMP-Neu5Ac to decorate their glycoconjugates. For selected bacteria we also show this strategy complements two other glycoengineering techniques, Metabolic Oligosaccharide Engineering (MOE) and Selective Exo-Enzymatic Labeling (SEEL), and that together they provide tools to modify, label, detect and visualize sialylation of bacterial LOS.

Divergent effects of tumor necrosis factor (TNF) in sepsis: a meta-analysis of experimental studies

IntroductionExperimental studies in animals have yielded conflicting results on the role of Tumor Necrosis Factor (TNF) in sepsis and endotoxemia, with some reporting adaptive and others inappropriate effects. A meta-analysis of the available literature was performed to determine the factors explaining this discrepancy.MethodsThe study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The protocol was registered with PROSPERO (CRD42020167384) prior to data collection. PubMed and Embase were the databases queried. Risk of bias was evaluated using the SYRCLE Risk of Bias Tool. All animal studies investigating sepsis-related mortality and modified TNF signaling were considered eligible. The exclusion criteria were: lack of mortality data, 7-day mortality rates below 10% in both wild type and TNF-altered pathway animals, and absence of an English abstract. To determine the role of TNF according to the experimental protocol, three approaches were used: first an approach based on the statistical significance of each experiment, then the pooled mortality was calculated, and finally the weighted risk ratio for mortality was assessed.ResultsA total of 175 studies were included in the analysis, comprising a total of 760 experiments and involving 19,899 animals. The main species used were mice (77%) and rats (21%). The most common method of TNF pathway modulation was TNF pathway inactivation that was primarily associated with an inappropriate secretion of TNF. At the opposite, TNF injection was associated with an adaptive role of TNF. Lipopolysaccharide (LPS) injection was the most used stimulus to establish an infectious model (42%) and was strongly associated with an inappropriate role of TNF. Conversely, live bacterial models, especially the cecal ligation and puncture (CLP) model, pneumonia, meningitis, and gastrointestinal infection, were associated with an adaptive role. This was particularly evident for Listeria monocytogenes, Streptococcus pneumoniae.ConclusionThe role of TNF during infection varies depending on the experimental model used. Models that mimic clinical conditions, based on virulent bacteria that cause high mortality even at low inocula, demonstrated an adaptive role of TNF. Conversely, models based on LPS or low-pathogenic live bacteria, administered at doses well above physiological thresholds and combined with early antibiotic therapy, were associated with an inappropriate role.Graphical abstract

Muscle protein catabolism and splanchnic arginine consumption drive arginine dysregulation during Pseudomonas Aeruginosa induced early acute sepsis in swine.

Human sepsis is characterized by increased protein breakdown and changes in arginine and citrulline metabolism. However, it is unclear whether this is caused by changes in transorgan metabolism. We therefore studied in a Pseudomonas aeruginosa induced pig sepsis model the changes in protein and arginine related metabolism on whole body (Wb) and transorgan level. We studied 22 conscious pigs for 18 hours during sepsis, induced by infusing live bacteria (Pseudomonas aeruginosa) or after placebo infusion (control). We used stable isotope tracers to measure Wb and skeletal muscle protein synthesis and breakdown, as well as Wb, splanchnic, skeletal muscle, hepatic and portal drained viscera (PDV) arginine and citrulline disposal and production rates. During sepsis, arginine Wb production (p=0.0146), skeletal muscle release (p=0.0035) and liver arginine uptake were elevated (p=0.0031). Wb de novo arginine synthesis, citrulline production, and transorgan PDV release of citrulline, glutamine and arginine did not differ between sepsis and controls. However, Wb (p<0.0001) and muscle (p<0.001) protein breakdown were increased, suggesting that the enhanced arginine production is predominantly derived from muscle breakdown in sepsis. In conclusion, live-bacterium sepsis increases muscle arginine release and liver uptake, mirroring previous pig endotoxemia studies. In contrast to observations in humans, acute live-bacterium sepsis in pigs does not change citrulline production or arterial arginine concentration. We therefore conclude that the arginine dysregulation observed in human sepsis is possibly initiated by enhanced protein catabolism and splanchnic arginine catabolism, while decreased arterial arginine concentration and citrulline metabolism may require more time to fully manifest in patients.

Rapid lateral flow test for Mycobacterium tuberculosis complex and non-tuberculous mycobacteria differentiation

The diagnosis of mycobacterial infections, including both the Mycobacterium tuberculosis complex (MTBC) and non-tuberculous mycobacteria (NTM), poses a significant global medical challenge. This study proposes a novel approach using immunochromatographic (IC) strip tests for the simultaneous detection of MTBC and NTM. Traditional methods for identifying mycobacteria, such as culture techniques, are hindered by delays in distinguishing between MTBC and NTM, which can affect patient care and disease control. Molecular methods, while sensitive, are resource-intensive and unable to differentiate between live and dead bacteria. In this research, we developed unique monoclonal antibodies (mAbs) against Ag85B, a mycobacterial secretory protein, and successfully implemented IC strip tests named 8B and 9B. These strips demonstrated high concordance rates with conventional methods for detecting MTBC, with positivity rates of 93.9% and 85.9%, respectively. For NTM detection, the IC strip tests achieved a 63.2% detection rate compared to culture methods, considering variations in growth rates among different NTM species. Furthermore, this study highlights a significant finding regarding the potential of MPT64 and Ag85B proteins as markers for MTBC detection. In conclusion, our breakthrough method enables rapid and accurate detection of both MTBC and NTM bacteria within the BACTEC MGIT system. This approach represents a valuable tool in clinical settings for distinguishing between MTBC and NTM infections, thereby enhancing the management and control of mycobacterial diseases.Key points• Panel of mAbs for differentiating MTB versus NTM• IC strips for diagnosing MTBC and NTM after the BACTEC MGIT• Combined detection of MTP64 and Ag85B enhances diagnostic accuracy

A streamlined culturomics case study for the human gut microbiota research

Bacterial culturomics is a set of techniques to isolate and identify live bacteria from complex microbial ecosystems. Despite its potential to revolutionize microbiome research, bacterial culturomics has significant challenges when applied to human gut microbiome studies due to its labor-intensive nature. Therefore, we established a streamlined culturomics approach with minimal culture conditions for stool sample preincubation. We evaluated the suitability of non-selective medium candidates for maintaining microbial diversity during a 30-day incubation period based on 16S rRNA gene amplicon analysis. Subsequently, we applied four culture conditions (two preincubation media under an aerobic/anaerobic atmosphere) to isolate gut bacteria on a large scale from eight stool samples of healthy humans. We identified 8141 isolates, classified into 263 bacterial species, including 12 novel species candidates. Our analysis of cultivation efficiency revealed that seven days of aerobic and ten days of anaerobic incubation captured approximately 91% and 95% of the identified species within each condition, respectively, with a synergistic effect confirmed when selected preincubation media were combined. Moreover, our culturomics findings expanded the coverage of gut microbial diversity compared to 16S rRNA gene amplicon sequencing results. In conclusion, this study demonstrated the potential of a streamlined culturomics approach for the efficient isolation of gut bacteria from human stool samples. This approach might pave the way for the broader adoption of culturomics in human gut microbiome studies, ultimately leading to a more comprehensive understanding of this complex microbial ecosystem.

The Role of Probiotics in Gut Health and Disease

Gut health is widely seen as a critical component of general well-being, affected in large part by the gut microbiome, a complex collection of bacteria that live in the gastrointestinal system. Probiotics, which are live bacteria that provide health benefits when taken in suitable doses, are essential for maintaining and improving gut health. This review looks at how probiotics work, including how they modulate gut microbiota, improve intestinal barrier function, and reduce inflammation. The evidence for the advantages of probiotics in various gastrointestinal conditions, such as irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), and antibiotic-associated diarrhoea, is discussed. The paper also discusses problems in probiotic therapy, such as strain-specific effects and optimal dose. Overall, probiotics show great potential in both preventing and treating gastrointestinal illnesses, but more study is needed to enhance treatment methods and better understand individual responses. Keywords: Probiotics, Gut Health, Gut Microbiome, Gastrointestinal Disorders, Inflammation.

Pseudomonas mosselii: a potential alternative for managing pyrethroid-resistant Aedes aegypti.

Aedes aegypti is a widespread mosquito in tropical and subtropical regions that causes significant mortality and morbidity in humans by transmitting diseases, such as dengue fever and Zika virus disease. Synthetic insecticides, such as pyrethroids, have been used to control Ae. aegypti, but these insecticides can also affect nontarget organisms and contaminate soil and water. This study aimed to investigate the mosquitocidal activity of Pseudomonas mosselii isolated from pond sludge against larvae of Ae. aegypti. Based on the initial results, similar time-course profiles were obtained for the mosquitocidal activity of the bacterial culture and its supernatant, and the pellet resuspended in Luria-Bertani (LB) medium also showed delayed toxicity. These results imply that the toxic component can be released into the medium from live bacteria. Further research indicated that the toxic component appeared in the supernatant approximately 4 h after a 3-mL stock was cultured in 200 mL of LB medium. The stabilities of the P. mosselii culture and supernatant stored at different temperatures were also evaluated, and the best culture stability was obtained at 28 °C and supernatant stability at 4 °C. The bacterial culture and supernatant were toxic to larvae and pupae of not only susceptible Ae. aegypti but also pyrethroid-resistant strains. This study highlights the value of the mosquitocidal activity of P. mosselii, which has potential as an alternative insecticide to control pyrethroid-resistant Ae. aegypti in the field. © 2024 Society of Chemical Industry.

Deciphering contaminants and toxins in fermented food for enhanced human health safeguarding.

Fermented foods have been a component of the human diet since ancient times, including live bacteria employed to restore gut health, contributing to the frontline of functional food progression. Human concern about the harmful consequences of possible contaminants has increased significantly as their toxicity, carcinogenicity, and teratogenicity have become more publicized. In order to take preventive measures, it is essential to correctly identify and define the implications of contaminants and toxins in human health and intestinal microbiota balance for preventing or diagnosing epidemics before they cause damage. The longer food chain that results from urbanization and underreporting of diseases makes it harder to correlate contaminated food to disease, which in turn presents challenges to improving food safety. This research aims to present the potential physical, chemical, and microbiological pollutants and toxins found in fermented products and their effects on human health. The scope tackles various categories of fermented foods, such as dairy products, alcoholic and nonalcoholic beverages, fermented meat products, traditional bakery products, and fermented cereals and vegetables. Furthermore, it examines specific control processes such as rigorous sanitation protocols, advanced packaging technologies, regulatory harmonization, and decontamination methodologies used to prevent the release of contaminants from fermented foods. Future viewpoints and opportunities are briefly mentioned in the conclusion.

The preventive effects of native probiotic and postbiotic on inflammation and oxidative stress in DSS-induced colitis with normal diet: Which of these agents may offer greater advantages?

BackgroundMaintaining a well-rounded and healthy diet is essential to promote the well-being and optimal performance of the body, especially for those suffering from Inflammatory Bowel Disease (IBD). The objective of this study is to examine whether probiotics and postbiotics can modulate oxidative stress and inflammation, and to evaluate the properties of these compounds. MethodsA total of eighty eight strains of Lactobacillus and Bifidobacterium were assessed for their antioxidant activities. C57BL/6 mice were allocated into four groups: normal diet (ND) + PBS, ND + DSS, ND + DSS + 10⁹ cfu/ml of probiotics, and ND + DSS + 10⁹ cfu/ml of postbiotics. Biochemical antioxidant assays, along with colitis indices, were evaluated. The ELISA assay was conducted to measure oxidant/antioxidant properties and cytokines. Additionally, the genes enrolled in NF-kB and Nrf2 signaling pathways was analyzed. ResultsIn comparison to the groups exposed to DSS alone, mice that received our native agents in addition to DSS demonstrated an improvement in the negative effects induced by DSS on DAI and pathological scores, as well as on colon length and body weight. The levels of cytokines and antioxidant markers have also been normalized following the administration of our native agents, along with molecular markers. It should also be noted that our native postbiotic was able to develop more pronounced and significant anti-inflammatory and antioxidant effects in comparison to the probiotic strains. ConclusionIn this study, our native postbiotic has demonstrated a more pronounced ability to exhibit antioxidant and anti-inflammatory effects. This finding is particularly important for individuals with impaired immune function, for whom the use of live bacteria could be risky. Therefore, the utilization of agents like probiotics and postbiotics, which come with minimal side effects in compared to chemical drugs, could be essential in managing symptoms in IBD patients.

Evaluation of [68Ga]Ga-DOTA-AeK as a Potential Imaging Tool for PET Imaging of Cell Wall Synthesis in Bacterial Infections.

The ability of bacteria to recycle exogenous amino acid-based peptides and amino sugars for peptidoglycan biosynthesis was extensively investigated using optical imaging. In particular, fluorescent AeK-NBD was effectively utilized to study the peptidoglycan recycling pathway in Gram-negative bacteria. Based on these promising results, we were inspired to develop the radioactive AeK conjugate [68Ga]Ga-DOTA-AeK for the in vivo localization of bacterial infection using PET/CT. An easy-to-implement radiolabeling procedure for DOTA-AeK with [68Ga]GaCI3 followed by solid-phase purification was successfully established to obtain [68Ga]Ga-DOTA-AeK with a radiochemical purity of ≥95%. [68Ga]Ga-DOTA-AeK showed good stability over time with less protein binding under physiological conditions. The bacterial incorporation of [68Ga]Ga-DOTA-AeK and its fluorescent Aek-NBD analog were investigated in live and heat-killed Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Unfortunately, no conclusive in vitro intracellular uptake of [68Ga]Ga-DOTA-AeK was observed for E. coli or S. aureus live and heat-killed bacterial strains (p > 0.05). In contrast, AeK-NBD showed significantly higher intracellular incorporation in live bacteria compared to the heat-killed control (p < 0.05). Preliminary biodistribution studies of [68Ga]Ga-DOTA-AeK in a dual-model of chronic infection and inflammation revealed limited localization at the infection site with non-specific accumulation in response to inflammatory markers. Finally, our study demonstrates proof that the intracellular incorporation of AeK is necessary for successful bacteria-specific imaging using PET/CT. Therefore, Ga-68 was not a suitable radioisotope for tracing the bacterial uptake of AeK tripeptide, as it required chelation with a bulky metal chelator such as DOTA, which may have limited its active membrane transportation. An alternative for optimization is to explore diverse chemical structures of AeK that would allow for radiolabeling with 18F or 11C.

Enhanced carbon dioxide reduction in microbial electrosynthesis using amine-functionalized metal-organic framework catalyst

Microbial electrosynthesis (MES) is a promising technology that can reduce carbon dioxide (CO2) into valuable platform chemicals using microbial biocatalytic action. However, inefficient microbe-electrode interactions greatly reduce the current uptake by microbes, ultimately hampering the CO2 reduction reaction. Therefore, this study aimed to enhance microbe-electrode interaction using amine-functionalized metal-organic framework (MOF) catalysts such as NH2-UiO-66(Zr) and NH2-UiO-66(Zr/Ni) on the cathode. Both abiotic and biotic cyclic voltammetry (CV) revealed the highest reduction current response from the NH2-UiO-66(Zr/Ni)-modified cathode among the tested cathodes, such as NH2-UiO-66, Pt-C, and unmodified cathode (control). Thus, the MES using the NH2-UiO-66(Zr/Ni) cathode could achieve an acetic acid production rate of 1166 ± 31 mg/L·d at a coulombic efficiency of 76 ± 2 %, which was higher than the MES operations with NH2-UiO-66(Zr) and without catalyst with corresponding values of 912 ± 12 mg/L·d and 67 ± 3 %, and 428 ± 13 mg/L·d and 56 ± 4 %, respectively. Biofilm analyses using scanning electron microscopy and confocal microscopy showed thick biofilm development on the NH2-UiO-66(Zr/Ni) cathode with abundant live bacteria. The results suggest that the amine-functionalized MOF can enhance the interaction of microbes with the cathode, resulting in efficient and high-rate bioelectrochemical CO2 reduction to valuable organic chemicals.

Inhibition of Salmonella typhimurium infection in mice fed with live or heat‐killed Lactiplantibacillus plantarum MWFLp‐182

The effects of both live and heat‐killed states of Lactiplantibacillus plantarum MWFLp‐182 (L. plantarum MWFLp‐182) isolated from the faeces of long‐lived humans on preventing and relieving Salmonella infection were studied. Evaluation methods included RT‐qPCR measurement of inflammatory factors, histopathological analysis and non‐targeted metabolomics. The results showed that L. plantarum MWFLp‐182 in both states improved body weight loss, organ swelling and ileocolon pathological damage. They also protected against Salmonella infection by regulating key KEGG enrichment pathways and the expression levels of TNF‐a and IL‐6. It is worth noting that the function of live bacteria was better than that of heat‐killed bacteria.

Realtime bacteria detection and analysis in sterile liquid products using deep learning holographic imaging

We introduce a digital inline holography (DIH) method combined with deep learning (DL) for real-time detection and analysis of bacteria in liquid suspension. Specifically, we designed a prototype that integrates DIH with fluorescence imaging to efficiently capture holograms of bacteria flowing in a microfluidic channel, utilizing the fluorescent signal to manually identify ground truths for validation. We process holograms using a tailored DL framework that includes preprocessing, detection, and classification stages involving three specific DL models trained on an extensive dataset that included holograms of generic particles present in sterile liquid and five bacterial species featuring distinct morphologies, Gram stain attributes, and viability. Our approach, validated through experiments with synthetic data and sterile liquid spiked with different bacteria, accurately distinguishes between bacteria and particles, live and dead bacteria, and Gram-positive and negative bacteria of similar morphology, all while minimizing false positives. The study highlights the potential of combining DIH with DL as a transformative tool for rapid bacterial analysis in clinical and industrial settings, with potential extension to other applications including pharmaceutical screening, environmental monitoring, and disease diagnostics.