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The expression of flagellar proteins in Brucella species likely evolved through genetic transference from other microorganisms, and contributed to virulence, adaptability, and biofilm formation. Despite significant progress in defining the molecular mechanisms behind flagellar gene expression, the genetic program controlling biofilm formation remains unclear. The flagellar transcriptional factor (FtcR) is a master regulator of the flagellar system's expression, and is critical for B. melitensis 16M's flagellar biogenesis and virulence. Here, we demonstrate that FtcR mediates biofilm formation under hyperosmotic stress. Chromatin immunoprecipitation with next-generation sequencing for FtcR and RNA sequencing of ftcR-mutant and wild-type strains revealed a core set of FtcR target genes. We identified a novel FtcR-binding site in the promoter region of the osmotic-stress-response regulator gene betI, which is important for the survival of B. melitensis 16M under hyperosmotic stress. Strikingly, this site autoregulates its expression to benefit biofilm bacteria's survival under hyperosmotic stress. Moreover, biofilm reduction in ftcR mutants is independent of the flagellar target gene fliF. Collectively, our study provides new insights into the extent and functionality of flagellar-related transcriptional networks in biofilm formation, and presents phenotypic and evolutionary adaptations that alter the regulation of B. melitensis 16M to confer increased tolerance to hyperosmotic stress.
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Brucella melitensis , Brucelose , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biofilmes , Brucella melitensis/metabolismo , Regulação Bacteriana da Expressão Gênica , Humanos , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Virulência/genéticaRESUMO
ICE1 (Inducer of CBF Expression 1) encodes a MYC-like basic helix-loop-helix transcription factor that acts as a central regulator of cold response. In this study, we elucidated the function and underlying mechanisms of PtrICE1 from trifoliate orange [Poncirus trifoliata (L.) Raf.]. PtrICE1 was upregulated by cold, dehydration, and salt, with the greatest induction under cold conditions. PtrICE1 was localized in the nucleus and could bind to a MYC-recognizing sequence. Ectopic expression of PtrICE1 in tobacco and lemon conferred enhanced tolerance to cold stresses at either chilling or freezing temperatures. Yeast two-hybrid screening revealed that 21 proteins belonged to the PtrICE1 interactome, in which PtADC (arginine decarboxylase) was confirmed as a bona fide protein interacting with PtrICE1. Transcript levels of ADC genes in the transgenic lines were slightly elevated under normal growth condition but substantially increased under cold conditions, consistent with changes in free polyamine levels. By contrast, accumulation of the reactive oxygen species, H2O2 and O2 (-), was appreciably alleviated in the transgenic lines under cold stress. Higher activities of antioxidant enzymes, such as superoxide dismutase and catalase, were detected in the transgenic lines under cold conditions. Taken together, these results demonstrated that PtrICE1 plays a positive role in cold tolerance, which may be due to modulation of polyamine levels through interacting with the ADC gene.
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Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Carboxiliases/metabolismo , Regulação da Expressão Gênica de Plantas , Poliaminas/metabolismo , Poncirus/enzimologia , Adaptação Fisiológica , Sequência de Bases , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Carboxiliases/genética , Citrus/enzimologia , Citrus/genética , Citrus/fisiologia , Temperatura Baixa , Peróxido de Hidrogênio/metabolismo , Dados de Sequência Molecular , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Poncirus/genética , Poncirus/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Análise de Sequência de DNA , Cloreto de Sódio/farmacologia , Estresse Fisiológico , Nicotiana/enzimologia , Nicotiana/genética , Nicotiana/fisiologiaRESUMO
Aluminum alloys are widely used due to their exceptional properties, but the systematic relationship between their grain size and their tensile strength has not been thoroughly explored in the literature. This study aims to fill this gap by compiling a comprehensive dataset and utilizing machine learning models that consider both the alloy composition and the grain size. A pivotal enhancement to this study was the integration of hardness as a feature variable, providing a more robust predictor of the tensile strength. The refined models demonstrated a marked improvement in predictive performance, with XGBoost exhibiting an R2 value of 0.914. Polynomial regression was also applied to derive a mathematical relationship between the tensile strength, alloy composition, and grain size, contributing to a more profound comprehension of these interdependencies. The improved methodology and analytical techniques, validated by the models' enhanced accuracy, are not only relevant to aluminum alloys, but also hold promise for application to other material systems, potentially revolutionizing the prediction of material properties.
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Objectives: The mechanism of Brucella infection regulating macrophage phenotype has not been completely elucidated until now. This study aimed to determine the mechanism of Brucella abortus in the modulation of macrophage phenotype using RAW264.7 cells as a model. Materials and methods: RT-qPCR, ELISA and flow cytometry were used to detect the inflammatory factor production and phenotype conversion associated with M1/M2 polarization of macrophages by Brucella abortus infection. Western blot and immunofluorescence were used to analyze the role of nuclear factor kappa B (NF-κB) signaling pathway in regulation of Brucella abortus-induced macrophage polarization. Chromatin immunoprecipitation sequencing (Chip-seq), bioinformatics analysis and luciferase reporter assay were used to screen and validate NF-κB target genes associated with macrophage polarization and further verify its function. Results: The results demonstrate that B. abortus induces a macrophage phenotypic switch and inflammatory response in a time-dependent manner. With the increase of infection time, B. abortus infection-induced M1-type increased first, peaked at 12 h, and then decreased, whereas the M2-type decreased first, trough at 12 h, and then increased. The trend of intracellular survival of B. abortus was consistent with that of M2 type. When NF-κB was inhibited, M1-type polarization was inhibited and M2-type was promoted, and the intracellular survival of B. abortus increased significantly. Chip-seq and luciferase reporter assay results showed that NF-κB binds to the glutaminase gene (Gls). Gls expression was down-regulated when NF-κB was inhibited. Furthermore, when Gls was inhibited, M1-type polarization was inhibited and M2-type was promoted, the intracellular survival of B. abortus increased significantly. Our data further suggest that NF-κB and its key target gene Gls play an important role in controlling macrophage phenotypic transformation. Conclusions: Taken together, our study demonstrates that B. abortus infection can induce dynamic transformation of M1/M2 phenotype in macrophages. Highlighting NF-κB as a central pathway that regulates M1/M2 phenotypic transition. This is the first to elucidate the molecular mechanism of B. abortus regulation of macrophage phenotype switch and inflammatory response by regulating the key gene Gls, which is regulated by the transcription factor NF-κB.
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Brucella abortus , NF-kappa B , NF-kappa B/metabolismo , Glutaminase/metabolismo , Transdução de Sinais/fisiologia , Macrófagos/metabolismoRESUMO
Human brucellosis is one of the world's most common zoonoses, caused by Brucella infection and characterized by induced inflammation, which in severe cases can lead to abortion and sterility in humans and animals. There is growing evidence that traditional Chinese medicine (TCM) is beneficial as an adjunct to the treatment of brucellosis. However, its specific targets of action and molecular mechanisms remain unclear. In this study, a systematic pharmacological approach was applied to demonstrate pharmacological targets, biological functions, and signaling pathways of TCM as an adjunct to the treatment of brucellosis (TCMTB). The results of network pharmacology were further verified by in vitro experiments. Network analysis revealed that 133 active ingredients and 247 targets were screened in TCMTB. Further data analysis identified 21 core targets and 5 core compounds in TCMTB, including beta-sitosterol, quercetin, kaempferol, luteolin, and paeoniflorin. Gene ontology and the Kyoto Encyclopedia of Gene and Genome analysis showed that TCMTB might actively treat brucellosis by regulating inflammatory response, enhancing immune function, and targeting signaling pathways such as tuberculosis and TNF. Molecular docking results showed that multiple compounds could bind to multiple targets. Further, in vitro experiments confirmed that quercetin, among the active compounds screened, induced the strongest immunomodulatory and pro-inflammatory cytokine production during Brucella abortus infection. Further, quercetin induced nitric oxide production, which attenuated the ability of B. abortus to internalize THP-1 cells as well as intracellular survival. This study reveals the mechanism by which TCMTB aids in the treatment of brucellosis through a synergistic multicomponent, multipathway, and multitarget action. The contribution of quercetin treatment to B. abortus infection was demonstrated for the first time, which may be related to the quercetin-induced production of nitric oxide and immunomodulatory and inflammatory cytokines. These predictions of the core compounds and targets may be used in the future for the clinical treatment of brucellosis.
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Brucella can inhabit hostile environments, including osmotic stress. How Brucella responds collectively to osmotic stress is largely unexplored, particularly in spatially structured communities such as a biofilm. To gain insight into this growth mode, we set out to characterize the Brucella melitensis 16M biofilm, describe its phenotype, and carry out a comparative transcriptomic analysis between biofilms under osmotic stress and control conditions. We determined that the bacteria challenged with 1.5 M NaCl had a reduced ability to aggregate and form clumps and develop a biofilm; however, the salt stress promoted the release of the outer membrane vesicles from the biofilm. Together with the genotypical response to osmotic stress, we identified 279 differentially expressed genes in B. melitensis 16M grown under osmotic conditions compared with control conditions; 69 genes were upregulated and 210 downregulated. Under osmotic stress, the main changed genes of biofilm were predicted to be involved in flagellar assembly, cell envelope, translation, small RNA regulation, transport and binding proteins, and energy metabolism. In addition, the ABC transporter was enriched in the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. We highlight 12 essential ABC transporter genes associated with a bacterial response to osmotic stress at the biofilm stage, including one specific locus, BME_RS12880, mediating betaine accumulation in biofilms to eliminate osmotic stress. The current study results can help researchers gain insights into B. melitensis 16M biofilm adaptation to osmotic stress and provide information for developing intervention strategies to control Brucella.
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Despite the recognized epidemiological importance of ticks as vectors for pathogens that cause numerous zoonotic and veterinary diseases, data regarding the pathogens of pet dogs and their parasitic ticks in the Junggar Basin are scarce. In this study, a total of 178 blood samples and 436 parasitic ticks were collected from pet dogs in Junggar Basin, Xinjiang Uygur Autonomous Region (XUAR), north-western China. All ticks were identified as Rhipicephalus turanicus sensu stricto (s.s.) according to morphological and molecular characteristics. Rh. turanicus s.s. ticks were collected from pet dogs in China for the first time. Seven tick-borne pathogens, such as Ehrlichia chaffeensis, Anaplasma phagocytophilum, Rickettsia massiliae, Candidatus R. barbariae, Brucella spp., Rickettsia sibirica, and Anaplasma ovis, were detected from ticks, whereas the first five bacteria were detected from blood samples of dogs. Brucella spp. was the most predominant pathogen in both blood samples and ticks of pet dogs, with the detection rates of 16.29 and 16.74%, respectively. Moreover, 17 ticks and 1 blood sample were co-infected with two pathogens, and 1 tick was co-infected with three pathogens. This study provided molecular evidence for the occurrence of Anaplasma spp., Ehrlichia spp., Rickettsia spp., and Brucella spp. circulating in pet dogs and their parasitic ticks in Junggar Basin, north-western China. These findings extend our knowledge of the tick-borne pathogens in pet dogs and their parasitic ticks in Central Asia; therefore, further research on these pathogens and their role in human and animal diseases is required.
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[This corrects the article DOI: 10.3389/fimmu.2020.581517.].
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Objectives: The underlying mechanism of the inflammatory response against Brucellosis caused by Brucella remains poorly understood. This study aimed to determine the role of long non-coding RNAs (lncRNAs) in regulating of inflammatory and anti-Brucella responses. Materials and methods: Microarray analysis was performed to detect differentially expressed lncRNAs in THP-1 cells infected with an S2308 Brucella strain. The candidate lncRNAs were screened using bioinformatic analysis and siRNAs; bioinformatic prediction and luciferase reporter assay were also conducted, while inflammatory responses was assessed using RT-qPCR, western blot, immunofluorescence, ELISA, HE, and immunohistochemistry. Results: The lncRNA Gm28309 was identified to be involved in regulating inflammation induced by Brucella. Gm28309, localized in the cytoplasm, was down-expressed in RAW264.7 cells infected with S2308. Overexpression of Gm28309 or inhibition of miR-3068-5p repressed p65 phosphorylation and reduced NLRP3 inflammasome and IL-1ß and IL-18 secretion. Mechanistically, Gm28309 acted as a ceRNA of miR-3068-5p to activate NF-κB pathway by targeting κB-Ras2, an inhibitor of NF-κB signaling. Moreover, the number of intracellular Brucella was higher when Gm28309 was overexpressed or when miR-3068-5p or p65 was inhibited. However, these effects were reversed by the miR-3068-5p mimic. Conclusions: Our study demonstrates, for the first time, that LncRNAs are involved in regulating immune responses during Brucella infection, and Gm28309, an lncRNA, plays a crucial role in activating NF-κB/NLRP3 inflammasome signaling pathway.
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Brucella/imunologia , Regulação para Baixo/imunologia , Inflamação/imunologia , Macrófagos/imunologia , MicroRNAs/imunologia , NF-kappa B/imunologia , RNA Longo não Codificante/imunologia , Animais , Linhagem Celular , Feminino , Humanos , Interleucina-18/imunologia , Interleucina-1beta/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Células RAW 264.7 , Transdução de Sinais/imunologia , Células THP-1RESUMO
OBJECTIVE: To verify the pathogenesis in Chinese and to investigate the genetic rule of X-linked lymphoproliferative disease (XLP) therein. METHODS: The case history of a proband of XLP, male, aged 1 year and 5 months, who died 40 days after hospitalization, was reviewed. Fourteen his family members were interviewed for the development history, anamnesis, and underwent physical examination. Single-strand conformation polymorphism (SSCP-PCR) and sequencing were used to detect the SH2D1A mutation among the elder sister, younger brother, and parents of the poband. RESULTS: The proband and his elder brother suffered with virus-associated hemophagocytic syndrome and both died in 40 days after the disease coming on in the last two years in succession. The second exon of SH2D1A of the younger brother of the proband showed a nonsense mutation in SH2D1A gene: the C-T nucleotide substitution at nucleotide position 462 result in a stop codon and pre-mature termination of protein synthesis. The mother was proved as mutation heterozygote of the C and T nucleotide on the same site. The other members of the family were proved normal. The clinical manifestation of the younger brother of the proband was Langerhans cell histiocytosis. CONCLUSION: Langerhans cell histiocytosis may be a new clinical phenotype of XLP. The gene of SH2D1A is responsible for the disease of XLP in Chinese too. The newly developed method of SH2D1A mutation analysis may be suitable in the diagnosis of XLP in Chinese.
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Peptídeos e Proteínas de Sinalização Intracelular/genética , Transtornos Linfoproliferativos/genética , Mutação , Antígenos CD/análise , Antígenos de Diferenciação Mielomonocítica/análise , Sequência de Bases , China , Análise Mutacional de DNA , Saúde da Família , Feminino , Predisposição Genética para Doença , Humanos , Imuno-Histoquímica , Transtornos Linfoproliferativos/diagnóstico , Transtornos Linfoproliferativos/metabolismo , Masculino , Dados de Sequência Molecular , Linhagem , Reação em Cadeia da Polimerase , Polimorfismo Conformacional de Fita Simples , Estudos Retrospectivos , Proteínas S100/análise , Homologia de Sequência do Ácido Nucleico , Proteína Associada à Molécula de Sinalização da Ativação Linfocitária , Domínios de Homologia de src/genéticaRESUMO
Langerhans' cell histiocytosis (LCH) is a rare disease of unkown cause and is characterized by clonal proliferation of Langerhans cells. Here, we describe the case of a 22-month-old boy with LCH associated with X-linked lymphoproliferative disease (XLP). Sequence analysis of SH2D1A for mutations that cause T-cell dysfunction revealed a CT substitution at nucleotide 462. This is the first case that hints at an association between XLP and LCH.