Search Results (680)

Helicobacter pylori infects the human stomach and causes various gastrointestinal diseases. Saucerneol D is a type of lignan, which is a polyphenol compound that exists naturally in plants, and it is abundant in flaxseed, sesame seeds, whole grains, vegetables, and fruits. Saucerneol D is found in Saurus chinensis extract and has been reported to exert a variety of effects, such as antioxidant and anti-inflammatory abilities. However, its antibacterial effect against H. pylori has not been reported; therefore, we analyzed the effect of saucerneol D on H. pylori in the present study. Changes in the expression of pathogenic factors and gene transcription in H. pylori were observed after treatment with saucerneol D using Western blotting and RT-PCR. It was confirmed that saucerneol D suppressed the growth of H. pylori by decreasing the expression of the genes dnaN and polA, which are required for bacterial replication. Saucerneol D also reduced the secretion of the major pathogenic toxin protein, CagA, by downregulating the expression of type IV secretion system-composing proteins. Furthermore, saucerneol D reduced ammonia production by inhibiting the expression of urease proteins, which are essential for the survival of H. pylori in the acidic gastric environment. Additionally, saucerneol D decreased the expression of flaB, potentially reducing motility. Finally, it was confirmed that the expression of the sabA gene, associated with cell adhesion, was reduced. These results suggest that saucerneol D inhibits the growth of H. pylori and the expression of several pathogenic factors, indicating that saucerneol D has an antimicrobial effect against H. pylori. Full article

Background/Objectives: Acetaminophen (APAP) is used during 50–60% of pregnancies in the U.S. and has been associated with childhood respiratory morbidity, though the underlying mechanism remains unclear. APAP-induced injury is dependent on cell-specific expression of CYP2E1, the enzyme that metabolizes APAP into the mitochondrial toxin NAPQI. In mice, pulmonary Cyp2e1 expression peaks during the saccular stage of lung development on embryonic day 18 (E18). We investigated whether this developmental surge in Cyp2e1 triggers a pulmonary transcriptional response to maternal APAP exposure in embryonic lungs. Methods: Pregnant dams were exposed to APAP on E17 or E18 (150 or 250 mg/kg, IP) using doses derived from prior studies. We assessed the induction of NRF2 target genes and genes associated with inflammation, apoptosis and cellular stress due to their roles in APAP-induced oxidative and cellular stress. Results: At E17, maternal treatment with APAP induced pulmonary Cyp2e1 but resulted in inconsistent transcriptional changes. In contrast, maternal APAP at E18 triggered a robust transcriptional induction of Cyp2e1, NRF2 targets and markers of apoptosis, inflammation and cellular stress. Histopathology at birth after E18 APAP exposure revealed no acute pulmonary injury. Conclusions: We demonstrate a developmentally regulated, dose-dependent transcriptional response to maternal APAP in the embryonic murine lung. Importantly, transcriptional responses do not directly indicate lung injury; thus, future studies should assess protein-level changes following APAP exposure. This study underscores the need for further investigation into the role of developmentally regulated Cyp2e1 expression in APAP-induced toxicity and long-term respiratory morbidity. Full article

Animal venoms are rich in bioactive molecules with promising biotechnological potential. They comprise both protein and non-protein toxins. Among the protein toxins are enzymes, such as phospholipases A₂, proteases and L-amino acid oxidases (LAAOs). LAAOs exhibit antimicrobial, antiparasitic, antiviral, and anticancer effects, making them potential candidates for biotechnological applications. These activities are linked to their ability to catalyze oxidative reactions that convert L-amino acids into α-keto acids, releasing ammonia and hydrogen peroxide, which contribute to the immune response, pathogen elimination, and oxidative stress. However, in snakes of the Micrurus genus, LAAOs generally represent a small portion of the venom (up to ~7%), which limits their isolation and study. To overcome this, the present study aimed to produce Ml-LAAO, the enzyme from Micrurus lemniscatus, through heterologous expression in mammalian cells. The gene sequence was inferred from its primary structure and synthesized into the pSecTag2B vector for expression in HEK293T cells. After purification using a His Trap-HP column, the presence of recombinant Ml-LAAO (Ml-LAAOrec) was confirmed by Western blot and mass spectrometry, validating its identity. These results support successful recombinant expression of Ml-LAAO and highlight its potential for scalable production and future biotechnological applications. Full article

(1) Background: Pigs can be another host of Shiga toxin-producing E. coli (STEC), suggesting that pork products could be a potential risk to public health. A USDA National Animal Health Monitoring System (NAHMS) study revealed that Shiga toxin genes were detected in more than half of samples nationwide but only about a quarter of samples from the state of Illinois. To characterize the presence of STEC in Illinois pigs better and to explore the discrepancy between Illinois and other swine-producing states, we increased the sampling size and collected samples in different regions of the state and in different months to detect Shiga toxin genes in Illinois finisher pigs and subtyped the Shiga toxin genes further to assess any potential risk of STEC originating from Illinois pigs to human health. (2) Methods: Fecal samples were collected from 471 Illinois finisher pigs at different locations from October 2021 to September 2022. DNA samples were extracted from individual fecal samples and PCR-tested for Shiga toxin genes (stx1, stx2) and then toxin subtypes (stx2a, stx2c, stx2d, and stx2e). (3) Results: The data showed that the stx2 gene was detected in 61% of the fecal samples (285/471), whereas stx1 was detected only in 0.4% of the samples (2/471). The data also indicated a lower prevalence of stx genes in the samples collected in certain cold months (36% in October and 19% in March) compared to that in those from warm months (56% to 100% from April to September). Stx2d, a subtype associated with severe human illness, was detected in 2% of the samples (10/471); in contrast, stx2e, which is expressed by E. coli strains causing diarrhea and edema disease in pigs, was the most detected (49%; 229/471). (4) Conclusions: The high prevalence of Shiga toxin genes in the fecal samples from Illinois finisher pigs suggests that Stx-positive E. coli strains circulate in Illinois pig farms. However, the highly detected stx2e-positive STEC (or enterotoxigenic E. coli, ETEC) strains are associated with diarrhea and edema disease in pigs, indicating the need for disease prevention or control for pigs but unlikely a safety concern for Illinois pork products or a major risk of human illnesses. Full article

Fumonisin B1 (FB1) is a prevalent mycotoxin in moldy grains and feeds, highly toxic to livestock and compromising product quality while threatening food safety. Poultry exhibit low susceptibility to FB1, but the underlying tolerance mechanisms remain unclear. Traditional 3D chicken intestinal organoid models cannot simulate direct interaction between the epithelial monolayer and FB1, limiting the study of FB1–chicken intestinal crosstalk. Here, we established a 2D chicken intestinal organoid monolayer model, derived from intestinal crypts of 18-day-old specific pathogen-free chicken embryos, to systematically explore poultry’s resistance mechanisms against FB1. Using this model, we compared FB1-induced effects with those in a porcine intestinal epithelial cell model. Results showed that FB1 exposure did not reduce transepithelial electrical resistance, induce abnormal expression of tight junction genes, or cause significant fluctuations in inflammatory factor levels in chicken intestinal organoid monolayers. Mechanistically, FB1 enhances chicken intestinal stem cell function by activating the Wnt/β-catenin pathway, thereby promoting epithelial regeneration and renewal to increase FB1 resistance and decrease toxin sensitivity in chickens. This study reveals a strategy for enhancing FB1 tolerance in poultry by promoting intestinal stem cell function, providing a new perspective for developing mycotoxin prevention and control strategies. Full article

Dioryctria abietella (Lepidoptera: Pyralidae) is a destructive forest pest for coniferous trees. Bacillus thuringiensis has been widely applied in forestry as a biological control agent to control it. However, the mechanisms of Bt-induced mortality in D. abietella, particularly its effects on gene expression and enzyme activities, remain unclear. Here, bioassay, enzyme assay, transcriptome sequencing, and gene expression profiling were employed to explore the relationship between the toxin-receptor, defense, and lethal mechanisms of D. abietella after Bt exposure. In a toxicity bioassay, Bacillus thuringiensis galleriae 05041 strain (Bt05041) was the most toxic insecticide to the larvae of D. abietella, with LC₅₀ values of 3.15 × 10⁸ Colony-Forming Units (CFUs) mL⁻¹ at 72 h after treatment. Transcriptome analysis revealed that the gene expression patterns of D. abietella after 8 h of Bt05041 exposure (Bt8) varied considerably from the Bt05041-treated for 2 h group (Bt2). In the Bt2 group, differentially expressed genes were significantly enriched in cellular and bioenergy pathways of lysosome, insulin signaling, cGMP-PKG signaling, etc. Immune-related pathways were activated, namely cAMP, AMPK, MAPK, Rap1, IMD, and Toll pathways. Meanwhile, Bt8 treatment caused metabolic changes in basic substances such as amino acids, glucose, nucleic acids, and fatty acids. Bt05041 exposure activated the activities of defense enzymes and induced gene expression changes in D. abietella larvae. Among them, most Bt-receptor genes had higher expression levels than defense enzyme genes. Overall, these findings reveal a possible mechanism underlying Bt-mediated death in D. abietella larvae. This work provides valuable information in terms of biological control strategies. Full article

Aedes aegypti, a crucial vector mosquito that transmits many diseases that cause millions of deaths worldwide, can be controlled with Bacillus thuringiensis subsp. israelensis (Bti). The larvicidal activity of Bti against Ae. aegypti is due primarily to Cry4Aa, Cry4Ba, and Cry11Aa, and Cyt1Aa, a protein that synergizes the activity of the Cry proteins. Interestingly, Galectins-6 and Galectins-14, members of a family of β-galactoside-binding proteins that play a role in immune responses insects, have been shown to decrease the activity of Bti toxins. The activity of other Galectins, particularly Galectin-8A, against the Cry proteins is not known. Toward this end, we cloned the gene coding for galactin-8A and expressed the recombinant protein and purified protein. The bioassay results indicated that Galectin-8A can also reduce the toxicity of Cry11Aa, but it was much stronger than Galectin-6. To investigate the interactions among Galectin-8A, Cry11Aa, and toxin receptors, Octet Red System analysis, Western blot, far-Western blot, and ELISA assay were also performed. The Octet Red System result showed that Galectin-8A could also bind to BBMVs of Ae. aegypti, with a lower kDa value than that of Galectin-6, indicating that Galectin-8A had a stronger binding affinity to BBMVs than Galectin-6. Western blot, far-Western blot, and ELISA assay analyses also demonstrated that Galectin-8A bound to Ae. aegypti receptor ALP1 and APN2, consistent with the protein docking simulation results. These findings support the conclusion that Galectin-8A blocks with ALP1 and APN2 more effectively than Galectin-6, which may subsequently reduce the toxicity of Cry11Aa in Ae. aegypti. Full article

The use of viruses as natural pathogens of pest insects is a promising approach in biocontrol. The main drawback of this approach is its relatively slow mode of action, which could be addressed through genetic modifications of the strains used. In this article, we propose the use of the commercially available Bac-to-Bac system for infecting pest insects with a recombinant virus and assessing the impact of various molecules on their viability. Using the laboratory-friendly model organism Galleria mellonella and baculovirus carrying the eGFP gene, we demonstrated a 100% infection rate, with a consistent and stable spread of the viruses throughout insect bodies and a gradual increase in recombinant protein expression. Notably, at day 5 post-infection the insects remained viable and active. This approach enables the identification of pathogenic effects caused by the virus-induced expression of other molecules, such as toxins. Full article

Background/Objectives: Camellia sinensis (L.) Kuntze or tea contains bioactive compounds such as catechin and caffeine, known for their antimicrobial and health-promoting properties. Colibactin-producing Escherichia coli are linked to genotoxicity in colon epithelial cells, potentially contributing to colorectal disease. This study aimed to evaluate the inhibitory effects of tea extracts (green, oolong, and black) and the phytochemicals catechin and caffeine on E. coli pathogenesis mediated by colibactin toxins, including transient infections, DNA damage, and cell cycle alterations in Caco-2 colon cells. Methods: Tea extracts were analyzed by HPLC for phytochemical content. Their antimicrobial activity against colibactin-producing E. coli (ATCC 25922) was assessed. Caco-2 cells were infected with the bacteria and treated with tea extracts or compounds. Cell viability was measured by MTT assay, DNA damage was measured by alkaline comet assay, and the expression of CDK-1, CDK-2, and Ki-67 genes was measurd by qRT-PCR. Results: Tea extracts and catechin inhibited colibactin-producing E. coli and significantly protected Caco-2 cells. Oolong tea showed the highest protection (90.78 ± 2.76%), with others maintaining viability above 80%. DNA damage was markedly reduced, and cell cycle regulation improved. All extracts upregulated CDK-1 and downregulated CDK-2, aiding in cell cycle restoration. Ki-67 expression indicated enhanced cell proliferation during infection. Conclusions: This study highlights new findings showing that tea extracts, including green, oolong, and black tea, as well as the tea compounds catechin and caffeine, can protect against DNA damage and help maintain the normal cell cycle of colon cells infected with E. coli-producing colibactin toxin. These results support their potential role in preventing and mitigating infections caused by such E. coli strains while promoting colon cell health. Full article

Fusarium verticillioides, an important global pathogenic fungus, compromises crop quality and yield by infecting maize, sugarcane, and some Solanaceae, endangering food security through contaminated grains and cereals with the fumonisin B1 (FB1) toxin. While Con7 has been reported as a transcription factor involved in the sporulation and pathogenicity of some pathogenic fungi, the function of FvCon7 and its regulatory genes in F. verticillioides remains uncharacterized. Gene deletion mutants of ΔFvcon7 were constructed through homologous recombination, which exhibited defects in vegetative growth, survival, sporophore development, conidiation, conidial germination, and carbon metabolism. Carbon metabolism defects led to a significant accumulation of glycogen granules in hypha and lipid bodies in conidia. Additionally, ΔFvcon7 displayed impaired cell wall structure and integrity, along with an altered expression of genes encoding cell wall-degrading enzymes (such as chitinase), as detected by qRT-PCR. Moreover, Fvcon7 also plays a role in the pathogenicity of maize and sugarcane through different splicing, defective conidia, reduced survival viability, differential expression of secreted proteins, and deficiencies in antioxidant stress capacity. Furthermore, using yeast one-hybrid (Y1H) assays, FvCon7 was found for the first time to directly regulate the expression of FvFUMs by binding to the CCAAT box within the promoters of six key FvFUMs, thereby affecting FB1 production. Overall, FvCon7 functions as a global transcription factor regulating multiple phenotypes. This study provides a theoretical basis for elucidating the mechanism of transcription factor FvCon7 regulating toxin production and pathogenesis in F. verticillioides. Full article

Live-attenuated vaccines face a critical challenge in balancing immunogenicity with safety. To address this, we engineered programmable finite-replicated organisms (FROs) by depositing a limited number of indispensable components (such as noncanonical amino acids, ncAAs) within the cell, consuming the coenabling precise control of bacterial replication capability while preserving antigenic breadth. Two strategies were adopted to achieve the following purposes: (1) encoding ncAA in essential genes; (2) encoding ncAA in antitoxin of toxin–antitoxin (TA) systems. As noncanonical amino acids, 3,5-dichlorotyrosine (Cl2Y) was encoded by the amber codon (TAG) and inserted into the essential genes (e.g., serS, murG, and dnaA) or antitoxin genes. After optimizing expression and the number of amber codons in the storage genes, the FRO cells can grow up to six generations, achieving amplification approaching 100 times after depletion of the ncAA in the growth medium. The escape frequencies are 10⁻⁵ to 10⁻⁷, which need to be optimized by combining multiple storage genes in the same genome in the future. This work holds the potential to amplify the amounts of antigens for vaccines, potentially accelerating the development of next-generation vaccines against antibiotic-resistant threats. Full article

The gastrointestinal tract is affected by multiple ailments that manifest with similar chemical, subcellular, and cellular changes, such as those in intestinal ischemia–reperfusion injury (IRI). The main chemical changes that are described under IRI conditions include the depletion of oxygen available for normal metabolism and the abundant production and increase in intracellular and extracellular concentrations of hydrogen peroxide and other reactive oxygen species (ROS). The enzymes causing this accumulation are xanthine dehydrogenase turning into xanthine oxidase, nicotinamide adenine dinucleotide phosphate oxidase, and nitric oxide synthase. The cellular changes revolve around an oxygen-sensing system that is responsive to varying oxygen levels, which has Hypoxia-Inducible Factors (HIFs) at its base. HIFs are transcription factors, the intracellular concentrations of which significantly increase under hypoxic conditions. Upon activation, they alter the expression of gene sets to ensure appropriate cellular adjustment to the hypoxic and IRI environment. Despite the primary regulation of the system involving oxygen, it is interconnected with multiple other subcellular and cellular functions. Thus, it represents a linchpin control mechanism of cellular adaptation. The effect of HIF activation in intestinal cells aims at preserving the structural integrity of the intestinal lining. The effect in different subtypes of leucocytes aims at immune system activation to protect against previously luminally located and subsequently invading pathogens and toxins. All in all, the HIF system is an integral part of cellular and tissue compensation against intestinal IRI. Full article

With the increasing severity of forest pest problems, breeding insect-resistant varieties has become a crucial task for the sustainable development of forestry. The highly insect-resistant triploid Populus line Pb29, genetically modified with BtCry1Ac, served as the maternal parent in controlled hybridization with three paternal Populus cultivars. Hybrid progenies were obtained through embryo rescue and tissue culture. Results showed that 4 °C storage was favorable for pollen preservation, with 84K poplar exhibiting superior pollen viability and embryo germination rates. All progenies displayed significantly lower seedling height and ground diameter growth than the maternal parent (p < 0.05), with some showing leaf shape and branching variations. Among the three crosses, the 84K-sired progeny exhibited the best growth performance but the highest variability. PCR analysis confirmed stable inheritance of the BtCry1Ac and Kan genes from Pb29, showing tight linkage. Progenies carrying BtCry1Ac exhibited detectable gene transcription and toxic protein accumulation, though expression levels varied due to copy number, insertion sites, and potential co-suppression effects. Ploidy analysis suggested all hybrids were aneuploid, with lower survival rates than the maternal parent. Insect-feeding assays confirmed high resistance in all BtCry1Ac-inheriting progenies, with an average larval mortality rate of 97.03%. Mortality rates and death indices significantly correlated with transcript abundance and toxin protein levels. These results demonstrate that BtCry1Ac insect resistance is stably inherited through hybridization. Transgene expression appears co-modulated by copy number, insertion sites, and ploidy status. Simultaneously, it was found that the aneuploid progeny derived from triploid hybridization exhibited growth disadvantages. This provides an important basis for subsequent poplar improvement breeding. Full article

Background: Clostridium perfringens (C. perfringens) type A is a major cause of enteritis in farmed and wild deer populations, leading to significant economic losses in the deer industry. This bacterium produces toxins that damage the intestine. Methods: In this study, we performed transcriptome analysis by establishing an intestinal circulation model of the intestines of fallow deer (Dama Dama) inoculated with C. perfringens type A versus those not inoculated with C. perfringens type A. In a further step, we determined the protein content of immunoinflammation-related molecules by ELISA and the antioxidant capacity of the intestine to investigate the molecular mechanisms of C. perfringens type A-induced enteritis. Results: Transcriptome analysis revealed significant enrichment of pathways related to the haematopoietic system, oxidative stress, the immune system and intestinal tight junctions. Additionally, C. perfringens α-toxin enters the intestine and may be recognized by TLR6, activating the immune system, increasing the secretion of various cytokines and inflammasome components, inducing oxidative stress and damaging the intestine. Conclusions: This study provides a comprehensive transcriptomic basis for understanding the selective differential expression of genes in deer enteritis induced by C. perfringens type A and provides a broader guide for finding therapeutic approaches to deer enteritis. Full article

Genomic islands (GIs) including integrative and conjugative elements (ICEs), prophages, and integrative plasmids are central drivers of horizontal gene transfer in bacterial plant pathogens. These elements often carry cargo genes encoding virulence factors, antibiotic and metal resistance determinants, and metabolic functions that enhance environmental adaptability. In plant-pathogenic species such as Pseudomonas syringae, GIs contribute to host specificity, immune evasion, and the emergence of novel pathogenic variants. ICEclc and its homologs represent integrative and mobilizable elements whose tightly regulated excision and transfer are driven by a specialized transcriptional cascade, while ICEs in P. syringae highlight the ecological impact of cargo genes on pathogen virulence and fitness. Pathogenicity islands further modulate virulence gene expression in response to in planta stimuli. Beyond P. syringae, GIs in genera such as Erwinia, Pectobacterium, and Ralstonia underpin critical traits like toxin biosynthesis, secretion system acquisition, and topoisomerase-mediated stability. Leveraging high-throughput genomics and structural biology will be essential to dissect GI regulation and develop targeted interventions to curb disease spread. This review synthesizes the current understanding of GIs in plant-pathogenic gammaproteobacteria and outlines future research priorities for translating mechanistic insights into sustainable disease control strategies. Full article