Search Results (120)

Brucellosis remains a major zoonotic disease that affects both public health and animal production worldwide. Conventional live vaccines, including S19, RB51, and A19, are commonly used for disease control; however, concerns regarding their safety and performance under field conditions limit their application. Targeted gene deletion in Brucella abortus S2308 has generated multiple candidate vaccine strains, but their protection relative to conventional vaccines has not yet been clearly established. We synthesized evidence from 15 mouse studies to compare the protective performance of S2308-derived gene-deletion mutants with that of conventional vaccines. The pooled estimate did not show a statistically significant difference in splenic bacterial burden after challenge between mutant and conventional vaccine groups (mean difference [MD] = 0.38, 95% CI: −0.07 to 0.84; p = 0.10), although substantial heterogeneity was observed (I² = 95.38%). Heterogeneity was partially explained by mouse strain, mouse age, the functional categories of deleted genes, number of deletions, and challenge dose. Mutants targeting signal-regulatory genes tended to be associated with lower splenic bacterial loads than those targeting genes involved in lipopolysaccharide (LPS) biosynthesis. Overall, based on post-challenge splenic bacterial burden, current mouse evidence suggests that S2308-derived gene-deletion mutants may reduce bacterial burden to an extent broadly comparable to that achieved by conventional Brucella vaccines in mice. The observed association between signal regulation-related gene deletions and lower splenic bacterial burden should be regarded as exploratory and requires further validation using broader protective endpoints and studies in natural target hosts. Full article

Background/Objectives: The genes encoding HSPA1A, HSPA1B, and HSPA1L, located in the MHC class III region at 6p21.3–22.1, a region implicated in susceptibility to schizophrenia, are critical regulators of neurodevelopmental processes and contribute to synaptic neuroprotection. This study investigated whether the HSPA1A, HSPA1B, and HSPA1L genes are associated with schizophrenia. Methods: We sequenced the coding regions of HSPA1A, HSPA1B, and HSPA1L from 100 patients with schizophrenia to identify genetic variants. Further, we conducted a genetic association analysis of three SNPs (rs9469057, rs142416335, and rs2075800) in the HSPA1L gene in 519 patients with schizophrenia and 1492 healthy controls from the Taiwan Biobank. We analyzed the function of the HSPA1L protein via immunoblotting. Results: We identified 17 coding variants, including 8 missense and 9 synonymous mutations, in 100 patients with schizophrenia. Three variants (HSPA1L^p.Ala8Pro, HSPA1L^p.Ala8Thr, and HSPA1L^p.Glu602Lys) in the HSPA1L gene did not exhibit any significant differences in allele or genotype frequencies between patients and control subjects. Notably, one ultra-rare missense mutation, HSPA1L^p.Val262Met, was not documented in the control sample in Taiwan BioBank. Immunoblotting revealed HSPA1L^p.Val262Met mutant with decreased protein expression in SH-SY5Y cells compared with the wild type. Conclusions: While common variants in the HSPA1A, HSPA1B, and HSPA1L genes do not seem to be significant genetic risk factors for schizophrenia in this cohort, the ultra-rare mutation, HSPA1L^p.Val262Met, significantly reduces protein expression. These preliminary findings suggest that a potential loss-of-function or reduced expression of the HSPA1L gene may be a predisposing factor contributing to schizophrenia vulnerability in certain individuals. However, the finding should be replicated in other independent samples. The in vitro and in vivo impacts of the associated mutation at the HSPA1L gene on the pathophysiology of schizophrenia are worthy of future investigation. Full article

Myostatin (MSTN) is a well-established negative regulator of skeletal muscle growth; however, its role in bone metabolism and osteogenic differentiation remains incompletely understood. In this study, untargeted and targeted metabolomic analyses were performed to investigate the metabolic effects of the MSTN^Del73C mutation during osteogenic differentiation of sheep bone marrow mesenchymal stem cells (BMSCs). Metabolomic profiles were analyzed in wild-type and MSTN^Del73C mutant BMSCs at 0, 7, and 14 days of osteogenic induction. During normal osteogenic differentiation, metabolites related to glycerophospholipid metabolism were repeatedly detected among significantly altered features, accompanied by marked increases in multiple lysophospholipid subclasses, including lysophosphatidylcholine (LPC), lysophosphatidylserine (LPS), and lysophosphatidylinositol (LPI). In contrast, MSTN^Del73C mutation was associated with significant reductions in several LPC and LPI species (p < 0.01 or p < 0.001), suggesting altered lipid metabolic profiles during differentiation. Targeted metabolomic validation further confirmed the altered abundance pattern of LPC 18:2. Collectively, these findings suggest that MSTN mutation is closely associated with metabolic remodeling during osteogenic differentiation and suggest potential involvement of glycerophospholipid-related metabolites involved in MSTN-related regulation of sheep BMSC osteogenesis. Full article

Clonal hematopoiesis of indeterminate potential (CHIP) and the gut microbiota-derived metabolite trimethylamine N-oxide (TMAO) are both linked to NLRP3-mediated cardiovascular inflammation, but their interaction has not previously been explored. This work proposes the CHIDT axis (clonal hematopoiesis–dysbiosis–TMAO), a feed-forward mechanism in which TET2 loss-of-function CHIP- and TMAO-generating Gram-negative gut dysbiosis mutually enhance cardiovascular risk. The model proceeds in three nodes. CHIP-associated intestinal immune dysregulation promotes luminal expansion of Gammaproteobacteria, which produce both trimethylamine via CntA/CntB-mediated L-carnitine oxidation and ADP-heptose as an obligate LPS biosynthetic intermediate. TMAO amplifies NLRP3 inflammasome activation through the SIRT3 → SOD2 → mtROS pathway. The evidence base of the CHIDT model is strongest for TET2-CHIP; the proposed extension to DNMT3A-CHIP rests on indirect, associative data and requires dedicated experimental confirmation before it can be considered established. TXNIP cascade, with predicted disproportionate potency in macrophages epigenetically primed by TET2 haploinsufficiency. High concentrations of TMAO have also been shown to suppress TET2 expression in endothelial cells through CYTB promoter hypermethylation, inducing NLRP3–GSDMD-dependent pyroptosis, although it remains unclear whether physiological TMAO levels can trigger this effect. Concurrently, ADP-heptose activates the ALPK1–TIFA–NF-κB pathway in bone marrow progenitors, favoring the expansion of mutant hematopoietic stem and progenitor cells. The model identifies three potential therapeutic strategies: NLRP3 inhibition, microbial TMA lyase inhibition, and microbiome-targeted reduction in Gram-negative bacteria. None has been tested in CHIP carriers stratified by plasma TMAO. Further studies in preclinical models and human cohorts integrating CHIP genotyping and TMAO quantification are needed to validate the CHIDT axis as a target for precision cardiovascular prevention. Full article

Legionella pneumophila is widely recognized as the principal organism responsible for Legionnaires’ disease. Modifications of surface-exposed lipopolysaccharide in L. pneumophila are key determinants of bacterial adaptation to host cells. Using a mutant strain deficient in N-methylation of legionaminic acid and fluorescence-based biophysical analyses, it was demonstrated that N-methyl groups linked to the acetimidoylamino group of legionaminic acid modulate the physicochemical properties of the bacterial cell surface and influence the interaction of L. pneumophila with macrophages. Loss of N-methyl groups reduced the efficiency of bacterial interaction with THP-1-derived macrophages and impaired intracellular proliferation. In addition, the presence of N-methyl groups in legionaminic acid contributes to increased TNF-α production in THP-1 macrophages stimulated with L. pneumophila sg1 LPS, without affecting IL-6 induction, suggesting that N-methylation of legionaminic acid may skew the early pro-inflammatory response toward TNF-α-dominated signaling during L. pneumophila infection. Full article

Endothelial cell (EC) barrier integrity is tightly regulated by the activity of the non-muscle myosin light chain kinase (nmMLCK) under diverse pathological inflammatory conditions (pneumonia, sepsis) and exposure to mechanical stress. Inflammatory stimuli, including lipopolysaccharide (LPS), cytokines, and damage-associated molecular patterns (DAMPs), increase EC permeability through nmMLCK-dependent EC paracellular gap formation. However, the exact mechanisms by which nmMLCK regulates vascular barrier dysfunction in acute lung injury (ALI) remain incompletely understood. We hypothesized that inflammation-induced ROS results in the peroxynitrite-mediated nitration of nmMLCK that contributes to EC barrier disruption. Human lung EC exposure to either the peroxynitrite donor, SIN-1, or to LPS, triggered significant nmMLCK nitration, which was abolished by the oxidant scavenger, MnTMPyP. Mass spectrometry of SIN-1-treated nmMLCK identified multiple nitrated tyrosines. Nitration of Y1410 proved a critical PTM as site-directed substitution with alanine (Y1410A) abolished both SIN-1- and LPS-induced nmMLCK nitration. nmMLCK nitration disrupts wild-type nmMLCK interaction with Kindlin-2, a cytoskeletal regulator of vascular barrier stability, whereas EC transfected with the Y1410A nmMLCK mutant exhibited preserved Kindlin-2 binding, reflected by alterations in trans-EC electrical resistance (TEER). Consistent with these observations, LPS-challenged murine lungs displayed enhanced nmMLCK nitration and diminished nmMLCK-Kindlin-2 association. Functionally, SIN-1 markedly impaired EC barrier integrity (TEER), which was not observed in ECs expressing the Y1410A mutant. Together, these findings suggest that nmMLCK nitration at Y1410 is a critical molecular mechanism contributing to vascular leakage, highlighting this modification as a potential therapeutic target to reduce inflammation-induced vascular permeability. Given nmMLCK’s established role in barrier regulation, we hypothesized that LPS-induced peroxynitrite formation may promote the nitration of nmMLCK tyrosine residues: a PTM that potentially contribute to nmMLCK’s regulation of EC barrier integrity. Full article

The phage-resistant mutant (PRM) strains of Escherichia coli (E. coli) exhibited abundant genetic and phenotypic diversity. IS elements played a vital role in creating various genetic divergences and regulating gene functions under phage infection stress. Genetic variations of PRM strains derived from E. coli MG1655 and mutation frequencies of coevolved E. coli populations with phages were explored by high-throughput sequencing and resequencing. Infrequent-restriction-site PCR (IRS-PCR) and carbon utilization test revealed the genetic and phenotypic diversity of the PRM strains. Numerous and discrepant mutation sites (MSs) were observed in the PRM strains and the coevolved populations, and many MSs were related to the synthesis of flagella and LPS, which often serve as receptors in a phage invasion. The insertions of various IS elements in key gene locations were also frequently found in the PRM strains, which indicate for the first time that IS elements played a vital role in generating genetic divergence and regulating gene functions under phage infection stress. Resequencing revealed that the coevolved populations at three evolving stages had discrepant profiles of MSs, and nearly all detected MSs occurred in the coevolved populations, which led to coexisting phages that increased the mutation rates and expedited the occurrence of the defective MSs in E. coli populations. In summary, our results reveal that the widespread and abundant presence of phages may provide one important force driving bacterial genomic evolution and prompt bacterial genetic divergence via accelerated mutation and increased mutation rates in the E. coli genome. Full article

Perennial ryegrass is a widely cultivated cool-season forage and turf grass species whose growth and development are limited by drought and high temperature. MAX2 is an F-box leucine-rich repeat (LRR) protein, which serves as a central component of strigolactone (SL) and karrikin (KAR) signaling pathways, involved in multiple growth and developmental processes as well as stress response. Here, we identified LpMAX2, a perennial ryegrass (Lolium perenne L.) homolog of Arabidopsis MAX2 (AtMAX2) and rice D3. LpMAX2 can interact with AtD14 and LpD14 in an SL-dependent manner, implying functional conservation with AtMAX2. Overexpression of LpMAX2 in the Arabidopsis max2-3 mutant partially rescued leaf morphology, hypocotyl elongation, and branching phenotypes, while fully restoring drought tolerance, highlighting the evolutionarily conserved roles of MAX2 in plant growth and drought resistance. In conclusion, LpMAX2 is evolutionarily conserved in SL/KAR signaling pathways, highlighting its potential function in drought adaptation. In addition to elucidating the biological function of LpMAX2, this study identifies a promising genetic target for enhancing stress resilience in forage grasses through biotechnological approaches. Full article

Plants adapt to phosphate starvation by remodeling root architecture and reallocating carbohydrates. Glucose-6-phosphate 1-epimerase (G6PE), a key enzyme in carbon and energy metabolism, is hypothesized to contribute to phosphate starvation responses. Here, we investigated the role of G6PE in rice and Arabidopsis through phenotypic, physiological, and molecular analyses of osg6pe and atg6pe mutants. Under normal-phosphate (NP) conditions, both mutants exhibited significantly reduced biomass and fresh weight compared with the wild-type (WT) plants, indicating growth inhibition caused by the mutations. Under low-phosphate (LP) conditions, the mutants displayed enhanced root growth, suggesting that G6PE functions as a negative regulator of radial root growth under phosphate deficiency. The osg6pe mutant showed elevated phosphate content and increased leaf starch accumulation under LP, whereas it accumulated more phosphate but less starch under NP. Expression analysis revealed that G6PE transcripts were suppressed under NP but remained relatively stable under LP. Notably, among phosphate starvation-induced (PSI) genes, only PHT1;4 showed notable transcriptional changes in both species. These findings indicate that G6PE contributes to phosphate homeostasis by modulating carbohydrate metabolism, restraining radial root growth, and selectively regulating PHT1 expression under phosphate-deficient conditions. Full article

Background: Obesity is a highly prevalent chronic disease characterized by excessive weight gain and fat accumulation. There is growing evidence that Lactiplantibacillus plantarum strains with bile salt hydrolase (BSH) activity are effective in preventing and alleviating obesity. Methods: Initially, we screened bacterial strains with high hydrolytic activity against glycochenodeoxycholic acid (GDCA), and constructed an isogenic bsh1 knockout mutant. Subsequently, male C57BL/6J mice fed a high-fat diet (HFD) were randomly assigned to receive daily gavage of either the wild-type Lp20 (Lp20-WT) or the bsh1-deficient mutant (Lp20-Δbsh1) for 8 weeks. Serum cholesterol levels and histopathological changes in liver sections were monitored. Hepatic gene expression was quantified by RT-qPCR, and fecal bacterial communities were analyzed via 16S rRNA gene sequencing. These comprehensive assessments aimed to evaluate metabolic improvements and uncover the potential mechanisms behind the observed effects. Results:L. plantarum Lp20 hydrolyzed 91.62% of GDCA, exhibiting the highest bile-salt hydrolase (BSH) activity among tested isolates. Whole-genome sequencing and in-silico analyses mapped this activity to bsh1; gene deletion of bsh1 confirmed the role of bsh1 in GDCA hydrolysis. Daily gavage of the wild-type strain (Lp20-WT) to diet-induced obese mice markedly attenuated weight gain, reduced inguinal white adipose tissue and mesenteric fat mass, and lowered serum TC and LDL-C by 20.8% and 33.3%, respectively, while decreasing ALT and AST levels and reversing hepatic steatosis. In contrast, the bsh1-null mutant (Lp20-Δbsh1) failed to elicit any measurable metabolic benefit. Mechanistically, Lp20-WT upregulated rate-limiting bile-acid synthetic enzymes CYP7A1 and CYP27A1, thereby accelerating the catabolism of cholesterol into bile acids. Concurrently, it activated hepatic TGR5 and FXR signaling axes to modulate hepatic metabolism. Moreover, Lp20-WT restructured the gut microbiota by notably enhancing the abundance of beneficial bacteria such as norank_f__Muribaculaceae, Akkermansia, and Alistipes, while reducing the abundance of potentially harmful taxa, including norank_f__Desulfovibrionaceae, Dubosiella, and Mucispirillum. Conclusions: This study provides direct evidence of BSH’s anti-obesity effects through gene deletion. Specifically, BSH lowers cholesterol by modulating hepatic bile-acid metabolism-related gene expression and altering the gut microbiota composition. However, the study is limited by a small sample size (n = 6), the use of male mice only, and its preclinical stage, indicating a need for further validation across diverse strains and human populations. Full article

Extracts of Cynanchi Auriculati Radix (RCA), derived from the roots of Cynanchum auriculatum Royle ex Wight. (CA), have been documented to possess anti-inflammatory and antioxidant properties. However, the molecular mechanisms of their anti-aging action remain unclear. The present study aimed to explore the potential anti-aging components and mechanisms of RCA. LC-MS/MS and network pharmacology were used to identify components and targets. In vitro, LPS-induced RAW264.7 macrophages were used to assess anti-inflammatory effects. In vivo, Caenorhabditis elegans models were employed to evaluate lifespan and stress resistance. Five bioactive components were identified. The ethyl acetate extract of RCA (RCAEA) inhibited LPS-induced M1 macrophage polarization by suppressing the expression of NO, PGE2, IL-1β, iNOS, COX-2, TNF-α, and IL-6 via the NF-κB pathway. In C. elegans, RCAEA extended lifespan and enhanced oxidative and heat stress resistance, without affecting reproduction. These benefits were mediated by the PMK-1/SKN-1 pathway, as confirmed using mutant strains. RCAEA is a promising anti-aging and anti-inflammatory agent, acting through NF-κB and PMK-1/SKN-1 signaling pathways. Full article

The Salmonella enterica serovar Typhimurium (ST) mutant lacking the msbB gene (ΔmsbB) has been widely studied as a candidate for attenuated bacterial vectors in therapeutic applications. Deletion of msbB results in LPS with under-acylated lipid A, which lowers endotoxicity while maintaining structural integrity. This attenuation has traditionally been attributed to reduced TLR4 activation due to weaker interaction between the modified lipid A and TLR4. In our study, we confirmed that ΔmsbB ST was less lethal than wild-type (WT) ST in a mouse sepsis model. However, this difference persisted even in TLR4- and caspase-11-deficient mice, suggesting that LPS signaling is not the primary determinant of virulence. In vitro, bone marrow–derived macrophages (BMDMs) from TLR4- or caspase-11-deficient mice showed only modest reductions in ST-induced cell death and cytokine production. Importantly, ΔmsbB ST behaved similarly to WT ST in these assays, further indicating that LPS-mediated signaling is not central to the observed attenuation. Our previous studies showed that ST-induced mortality in mice is primarily mediated through NLRC4 activation. Using qPCR and immunoblotting, we found that expression of NLRC4 activators was diminished in the ΔmsbB strain. Additionally, the mutant exhibited increased outer membrane permeability—likely contributing to its heightened antibiotic sensitivity—and reduced motility due to lower flagellin protein levels. In summary, the attenuation of virulence observed in the ΔmsbB strain is not directly due to altered LPS–TLR4 interactions, but rather an indirect effect of diminished expression of virulence factors that activate the NLRC4 inflammasome. Full article

Phosphorus (P) is a limiting nutrient for plant growth and productivity. Improving P use efficiency is important for crop production. In Lactuca sativa (lettuce), five phosphate starvation response 1 (PHR1) genes were identified and characterized through a bioinformatics approach. The expression patterns of LsaPHR1s were examined using qRT-PCR under various treatments, including devoid phosphorus (DP), low phosphorus (LP), high phosphorus (HP), darkness, ABA, IAA, and MeJA. The results indicate that LsaPHR1s in lettuce responded to phosphorus stress, hormones, and darkness. Furthermore, we engineered LsaPHR1.1 knock-out mutants via CRISPR/Cas9-mediated genome editing. Then, the mutants were subjected to phosphorus stress (DP, LP, and HP). In contrast to WT, the mutants improved nitrate and ammonium contents, increased antioxidant enzyme activity, and elevated antioxidant and chlorophyll contents. Our results offer a potential strategy for improving phosphorus stress tolerance in lettuce, which holds great significance for maintaining yield and quality. Full article

Salmonella enterica subsp. enterica serovar Typhimurium is a major foodborne pathogen whose ability to form biofilms contributes to persistent contamination in food-processing and clinical environments. This study investigated the anti-biofilm activity of the biosurfactant surfactin, produced by Bacillus subtilis, against S. Typhimurium wild type (LT2) and its lipopolysaccharide (LPS)-modified mutants on commonly used plastic surfaces such as polypropylene (PP) and polystyrene (PS). Biofilm formation was quantified using the crystal violet assay, revealing significantly higher biomass on PS compared to PP (p < 0.0001). Surfactin at 5 µg/mL was identified as the minimum biofilm inhibitory concentration (MBIC), significantly reducing biofilm formation in the wild-type and LPS mutants rfaL, rfaJ, rfaF (all p < 0.0001), and rfaI (p < 0.01). Further analysis using fluorescence microscopy and SYPRO^® Ruby staining confirmed a significant reduction in extracellular polymeric substances (EPSs) on PP surfaces following surfactin treatment, particularly in strains LT2 (p < 0.0001), rfa (p < 0.01), rfaL (p < 0.0001), rfaG (p < 0.05), and rfaE (p < 0.0001). These findings highlight the influence of LPS structure on biofilm development and demonstrate surfactin’s potential as an eco-friendly antimicrobial agent for controlling S. Typhimurium biofilms on food-contact surfaces. Analysis of mutants revealed that disruption of the rfa gene, which is involved in the biosynthesis of the outermost region of the lipopolysaccharide (LPS), significantly reduced bacterial attachment to polypropylene. This suggests that interactions between the external LPS layer and the plastic surface are important for colonisation. In contrast, mutants in core LPS biosynthesis genes such as rfaE and rfaD did not show any notable differences in attachment compared to the wild-type strain. This highlights the specific importance of outer LPS components, particularly under surfactant conditions, in mediating interactions with plastic surfaces. This work supports the application of biosurfactants in food safety strategies to reduce the risk of biofilm-associated contamination. Full article

Norovirus–bacterial interactions influence viral replication and immune responses, yet the molecular details that mediate binding of these viruses to commensal bacteria are unknown. Studies with other enteric viruses have revealed that LPS and other lipid/carbohydrate structures facilitate virus–bacterial interactions, and it has also been shown that human noroviruses (HuNoVs) can interact with histo-blood group antigen (HBGA)-like compounds on the surface of bacterial cells. Based on these findings, this study hypothesized that carbohydrate-based compounds were the ligands that facilitated binding of both human and murine noroviruses (MNV) to bacteria. Using glycan microarrays, competitive inhibition assays, and a panel of bacterial mutants, the project assessed the influence of specific glycans on viral attachment to bacteria. Protein-based interactions were also examined. The results supported previous work which demonstrated that HuNoVs strongly bind HBGA-like glycans, while MNV displayed distinct binding to other glycans including aminoglycosides and fucosylated structures. Ultimately, this work demonstrates that HuNoVs have more limited binding requirements for bacterial attachment compared to MNV, and the MNV binding to bacteria may involve both specific structures as well as electrostatic interactions. Given the importance of commensal bacteria during viral infection, defining the molecular mechanisms that mediate virus–bacteria interactions is critical for understanding infection dynamics and may be useful in the development of disease therapeutics and novel technologies for viral detection from food and environmental sources. Full article