RESUMO
PURPOSE: Boramino acids are a class of amino acid biomimics that replace the carboxylate group with trifluoroborate and can achieve the 18F-labeled positron emission tomography (PET) and boron neutron capture therapy (BNCT) with identical chemical structure. METHODS: This study reports a trifluoroborate-derived boronophenylalanine (BBPA), a derived boronophenylalanine (BPA) for BNCT, as a promising PET tracer for tumor imaging. RESULTS: Competition inhibition assays in cancer cells suggested the cell accumulation of [18F]BBPA is through large neutral amino acid transporter type-1 (LAT-1). Of note, [18F]BBPA is a pan-cancer probe that shows notable tumor uptake in B16-F10 tumor-bearing mice. In the patients with gliomas and metastatic brain tumors, [18F]BBPA-PET shows good tumor uptake and notable tumor-to-normal brain ratio (T/N ratio, 18.7 ± 5.5, n = 11), higher than common amino acid PET tracers. The [18F]BBPA-PET quantitative parameters exhibited no difference in diverse contrast-enhanced status (P = 0.115-0.687) suggesting the [18F]BBPA uptake was independent from MRI contrast-enhancement. CONCLUSION: This study outlines a clinical trial with [18F]BBPA to achieve higher tumor-specific accumulation for PET, provides a potential technique for brain tumor diagnosis, and might facilitate the BNCT of brain tumors.
Assuntos
Compostos de Boro , Neoplasias Encefálicas , Radioisótopos de Flúor , Fenilalanina , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Traçadores Radioativos , Animais , Feminino , Humanos , Camundongos , Compostos de Boro/análise , Compostos de Boro/metabolismo , Compostos de Boro/farmacocinética , Terapia por Captura de Nêutron de Boro , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/metabolismo , Radioisótopos de Flúor/análise , Radioisótopos de Flúor/metabolismo , Radioisótopos de Flúor/farmacocinética , Voluntários Saudáveis , Transportador 1 de Aminoácidos Neutros Grandes/metabolismo , Imageamento por Ressonância Magnética , Melanoma Experimental , Camundongos Endogâmicos C57BL , Sondas Moleculares/análise , Sondas Moleculares/metabolismo , Sondas Moleculares/farmacocinética , Fenilalanina/análogos & derivados , Fenilalanina/análise , Fenilalanina/metabolismo , Fenilalanina/farmacocinética , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
BACKGROUND: Intratumoral hemorrhage, though less common, could be the first clinical manifestation of glioma and is detectable via MRI; however, its exact impacts on patient outcomes remain unclear and controversial. The 2021 WHO CNS 5 classification emphasised genetic and molecular features, initiating the necessity to establish the correlation between hemorrhage and molecular alterations. This study aims to determine the prevalence of intratumoral hemorrhage in glioma subtypes and identify associated molecular and clinical characteristics to improve patient management. METHODS: Integrated clinical data and imaging studies of patients who underwent surgery at the Department of Neurosurgery at Peking Union Medical College Hospital from January 2011 to January 2022 with pathological confirmation of glioma were retrospectively reviewed. Patients were divided into hemorrhage and non-hemorrhage groups based on preoperative magnetic resonance imaging. A comparison and survival analysis were conducted with the two groups. In terms of subgroup analysis, we classified patients into astrocytoma, IDH-mutant; oligodendroglioma, IDH-mutant, 1p/19q-codeleted; glioblastoma, IDH-wildtype; pediatric-type gliomas; or circumscribed glioma using integrated histological and molecular characteristics, according to WHO CNS 5 classifications. RESULTS: 457 patients were enrolled in the analysis, including 67 (14.7%) patients with intratumoral hemorrhage. The hemorrhage group was significantly older and had worse preoperative Karnofsky performance scores. The hemorrhage group had a higher occurrence of neurological impairment and a higher Ki-67 index. Molecular analysis indicated that CDKN2B, KMT5B, and PIK3CA alteration occurred more in the hemorrhage group (CDKN2B, 84.4% vs. 62.2%, p = 0.029; KMT5B, 25.0% vs. 8.9%, p = 0.029; and PIK3CA, 81.3% vs. 58.5%, p = 0.029). Survival analysis showed significantly worse prognoses for the hemorrhage group (hemorrhage 18.4 months vs. non-hemorrhage 39.1 months, p = 0.01). In subgroup analysis, the multivariate analysis showed that intra-tumoral hemorrhage is an independent risk factor only in glioblastoma, IDH-wildtype (162 cases of 457 overall, HR = 1.72, p = 0.026), but not in other types of gliomas. The molecular alteration of CDK6 (hemorrhage group p = 0.004, non-hemorrhage group p < 0.001), EGFR (hemorrhage group p = 0.003, non-hemorrhage group p = 0.001), and FGFR2 (hemorrhage group p = 0.007, non-hemorrhage group p = 0.001) was associated with shorter overall survival time in both hemorrhage and non-hemorrhage groups. CONCLUSIONS: Glioma patients with preoperative intratumoral hemorrhage had unfavorable prognoses compared to their nonhemorrhage counterparts. CDKN2B, KMT5B, and PIK3CA alterations were associated with an increased occurrence of intratumoral hemorrhage, which might be future targets for further investigation of intratumoral hemorrhage.
Assuntos
Neoplasias Encefálicas , Glioma , Humanos , Masculino , Feminino , Glioma/complicações , Glioma/genética , Glioma/cirurgia , Glioma/patologia , Pessoa de Meia-Idade , Estudos Retrospectivos , Prognóstico , Adulto , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/complicações , Neoplasias Encefálicas/cirurgia , Neoplasias Encefálicas/patologia , Idoso , Estudos de Coortes , Adulto JovemRESUMO
Chemiluminescence (CL) is of great significance in biochemical analysis and imaging due to its high sensitivity and lack of need for external excitation. In this review, we summarized the recent progress of AIE-based CL systems, including their working mechanisms and applications in biochemical analysis, bioimaging, and disease diagnosis and treatment. In ion and molecular detection, CL shows high selectivity and high sensitivity, especially in the detection of dynamic reactive oxygen species (ROS). Further, the integrated NIR-CL single-molecule system and nanostructural CL platform harnessing CL resonance energy transfer (CRET) have remarkable advantages in long-term imaging with superior capability in penetrating deep tissue depth and high signal-to-noise ratio, and are promising in the applications of in vivo imaging and image-guided disease therapy. Finally, we summarized the shortcomings of the existing AIE-CL system and provided our perspective on the possible ways to develop more powerful CL systems in the future. It can be highly expected that these promoted CL systems will play bigger roles in biochemical analysis and disease theranostics.
Assuntos
Luminescência , Nanoestruturas , Medicina de Precisão , Diagnóstico por Imagem , Nanomedicina Teranóstica/métodosRESUMO
PorX/PorY is a two-component system (TCS) of Porphyromonas gingivalis that governs transcription of numerous genes including those encoding a type IX secretion system (T9SS) for gingipain secretion and heme accumulation. Here, an in vitro analysis showed that the response regulator PorX specifically bound to two regions in the promoter of porT, a known PorX-regulated T9SS gene, thus demonstrating that PorX/PorY can directly regulate specific target genes. A truncated PorX protein containing the N-terminal receiver and effector domains retained a wild-type ability in both transcription regulation and heme accumulation, ruling out the role of the C-terminal ALP domain in gene regulation. The PorX/PorY system was the only TCS essential for heme accumulation and concomitantly responded to hemin to stimulate transcription of several known PorX-dependent genes in a concentration-dependent manner. We found that PorX/PorY activated the sigH gene, which encodes a sigma factor known for P. gingivalis adaptation to hydrogen peroxide (H2O2). Consistently, both ΔporX and ΔsigH mutants were susceptible to H2O2, suggesting a PorX/PorY-σH regulatory cascade to confer resistance to oxidative stress. Furthermore, the ΔporX mutant became susceptible to high hemin levels that could induce oxidative stress. Therefore, a possible reason why hemin activates PorX/PorY is to confer resistance to hemin-induced oxidative stress. We also demonstrated that PorX/PorY was essential for P. gingivalis virulence because the ΔporX mutant was avirulent in a mouse model. Specifically, this TCS was required for the repression of proinflammatory cytokines secreted by dendritic cells and T cells in the P. gingivalis-infected mice.
Assuntos
Proteínas de Bactérias/metabolismo , Sistemas de Secreção Bacterianos/metabolismo , Porphyromonas gingivalis/metabolismo , Fatores de Virulência/metabolismo , Animais , Proteínas de Bactérias/genética , Regulação Bacteriana da Expressão Gênica , Camundongos , Mutação , Porphyromonas gingivalis/genética , Porphyromonas gingivalis/fisiologia , Processamento de Proteína Pós-Traducional , Fatores de Virulência/genéticaRESUMO
The pH 6 antigen (PsaA) of Yersinia pestis is a virulence factor that is expressed in response to high temperature (37°C) and low pH (6.0). Previous studies have implicated the PsaE and PsaF regulators in the temperature- and pH-dependent regulation of psaA. Here, we show that PsaE levels are themselves controlled by pH and temperature, explaining the regulation of psaA. We identify hundreds of binding sites for PsaE across the Y. pestis genome, with the majority of binding sites located in intergenic regions bound by the nucleoid-associated protein H-NS. However, we detect direct regulation of only two transcripts by PsaE, likely due to displacement of H-NS from the corresponding promoter regions; our data suggest that most PsaE binding sites are nonregulatory or that they require additional environmental cues. We also identify the precise binding sites for PsaE that are required for temperature- and pH-dependent regulation of psaA and psaE. Thus, our data reveal the critical role that PsaE plays in the regulation of psaA and suggest that PsaE may have many additional regulatory targets. IMPORTANCE Y. pestis, the etiologic agent of plague, has been responsible for high mortality in several epidemics throughout human history. The plague bacillus has been used as a biological weapon during human history and is currently one of the most likely biological threats. PsaA and PsaE appear to play important roles during Y. pestis infection. Understanding their regulation by environmental cues would facilitate a solution to impede Y. pestis infection.
Assuntos
Antígenos de Bactérias/metabolismo , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica/fisiologia , Yersinia pestis/metabolismo , Antígenos de Bactérias/genética , Proteínas de Bactérias/genética , Estudo de Associação Genômica Ampla , Concentração de Íons de Hidrogênio , Complexo de Proteína do Fotossistema I/genética , Complexo de Proteína do Fotossistema I/metabolismo , Ligação Proteica , Processamento Pós-Transcricional do RNA , Temperatura , Transcrição Gênica , Yersinia pestis/genéticaRESUMO
BACKGROUND: In this study, we sought to assess knowledge, attitudes, and behaviors regarding venous thromboembolism (VTE) prophylaxis among clinicians at a tertiary hospital of China. METHODS: An electronic questionnaire was sent to clinicians to gather information regarding demographic data (5 items), knowledge about VTE prophylaxis (21 items), behaviors regarding VTE prophylaxis (8 items), and attitudes regarding VTE prophylaxis (7 items). Answers of "strongly agree" and "agree" on the behaviors and attitude items were defined as affirmative responses. Clinicians were also asked to provide suggestions regarding VTE prophylaxis. RESULTS: A total of 867 clinicians were included in this study. The overall correct response rate for knowledge items was 60.9%. The median affirmative response rate for behavior items was 48.6% (range 29.5-80.3%), and the median affirmative response rate for attitude items was 98.7% (range 96.9-99.3%). Clinicians were most concerned about the adverse effects triggered by chemical VTE prophylaxis (79.5%) and possibility of a financial penalty when a patient could not be treated with VTE prophylaxis (72.3%). Low patient compliance and low level of clinician knowledge and participation were identified most commonly as difficulties involved in VTE prophylaxis. A total of 78 suggestions were collected; these suggestions generally focused on improving the quality and frequency of staff training (n = 24) and enhancing learning opportunities (n = 22). CONCLUSIONS: Although the clinicians' overall attitude toward VTE prophylaxis was positive, the knowledge level was relatively poor, and the rate of affirmative responses regarding behaviors was low. Medical institutions should improve clinician training regarding VTE prophylaxis.
Assuntos
Atitude do Pessoal de Saúde , Competência Clínica , Fibrinolíticos/uso terapêutico , Conhecimentos, Atitudes e Prática em Saúde , Padrões de Prática Médica , Tromboembolia Venosa/prevenção & controle , Adulto , China , Fibrinolíticos/efeitos adversos , Pesquisas sobre Atenção à Saúde , Hospitalização , Humanos , Pessoa de Meia-Idade , Educação de Pacientes como Assunto , Medição de Risco , Fatores de Risco , Inquéritos e Questionários , Tromboembolia Venosa/diagnóstico , Tromboembolia Venosa/etiologiaRESUMO
OBJECTIVES: To investigate the cognition of nurses on the control and treatment of venous thromboembolism in China, thereby providing suitable countermeasures for clinical venous thromboembolism prophylaxis and treatment. METHODS: In December 2019, a total of 1121 registered nurses from a university-affiliated hospital were selected to answer the self-designed and electronic questionnaire (Wenquanxing: www.wjx.cn/), which was designed to evaluate the nurses' knowledge (21 items), attitudes (6 items), and behaviors (9 items) toward venous thromboembolism prophylaxis. Descriptive, correlation, and regression analyses were conducted for data analysis. RESULTS: Of the included 1121 nurses, only 55.43% nurses selected 100% correct answer. The influencing factors of knowledge included the department, education, professional ranks, and venous thromboembolism nursing experience. The nurses from ICU department gained the highest score, but the nurses from pediatrics department obtained the lowest score. The nurses with higher education level and professional ranks, and nursing experiences achieved higher scores. The total positive response rate for the attitude-related items was 68.54%. Nurses were primarily concerned about the financial penalty due to the inability to complete the work (49.0%). An increasing workload is the second primary concern of nurses (40.8%). The increasing medical cost, extension of hospital stay, and exacerbation of doctor-patient conflicts were the most serious difficulties involved in venous thromboembolism prophylaxis. The total correct score rate for the behaviors was 56.19%. Nearly half of the nurses could not offer advice for venous thromboembolism patients. The nursing experience, department, and years of work were related to the scores of knowledge-related items (all P < 0.05). CONCLUSIONS: The overall knowledge level of the nurses was not optimistic. Although their general attitude toward venous thromboembolism prophylaxis was positive, their behaviors were influenced by many factors. Administrators should, therefore, make countermeasures to deal with these problems.
Assuntos
Atitude do Pessoal de Saúde , Conhecimentos, Atitudes e Prática em Saúde , Enfermeiras e Enfermeiros/psicologia , Tromboembolia Venosa/prevenção & controle , Adulto , China , Competência Clínica , Humanos , Pessoa de Meia-Idade , Padrões de Prática em Enfermagem , Fatores de Risco , Especialização , Inquéritos e Questionários , Tromboembolia Venosa/etiologiaRESUMO
BACKGROUND: The coronavirus disease 2019 (COVID-19) has been a pandemic worldwide. Old age and underlying illnesses are associated with poor prognosis among COVID-19 patients. However, whether frailty, a common geriatric syndrome of reduced reserve to stressors, is associated with poor prognosis among older COVID-19 patients is unknown. The aim of our study is to investigate the association between frailty and severe disease among COVID-19 patients aged ≥ 60 years. METHODS: A prospective cohort study of 114 hospitalized older patients (≥ 60 years) with confirmed COVID-19 pneumonia was conducted between 7 February 2020 and 6 April 2020. Epidemiological, demographic, clinical, laboratory, and outcome data on admission were extracted from electronic medical records. All patients were assessed for frailty on admission using the FRAIL scale, in which five components are included: fatigue, resistance, ambulation, illnesses, and loss of weight. The outcome was the development of the severe disease within 60 days. We used the Cox proportional hazards models to identify the unadjusted and adjusted associations between frailty and severe illness. The significant variables in univariable analysis were included in the adjusted model. RESULTS: Of 114 patients, (median age, 67 years; interquartile range = 64-75 years; 57 [50%] men), 39 (34.2%), 39 (34.2%), and 36 (31.6%) were non-frail, pre-frail, and frail, respectively. During the 60 days of follow-up, 43 severe diseases occurred including eight deaths. Four of 39 (10.3%) non-frail patients, 15 of 39 (38.5%) pre-frail patients, and 24 of 36 (66.7%) frail patients progressed to severe disease. After adjustment of age, sex, body mass index, haemoglobin, white blood count, lymphocyte count, albumin, CD8+ count, D-dimer, and C-reactive protein, frailty (HR = 7.47, 95% CI 1.73-32.34, P = 0.007) and pre-frailty (HR = 5.01, 95% CI 1.16-21.61, P = 0.03) were associated with a higher hazard of severe disease than the non-frail. CONCLUSIONS: Frailty, assessed by the FRAIL scale, was associated with a higher risk of developing severe disease among older COVID-19 patients. Our findings suggested that the use of a clinician friendly assessment of frailty could help in early warning of older patients at high-risk with severe COVID-19 pneumonia.
Assuntos
Infecções por Coronavirus , Idoso Fragilizado , Fragilidade/diagnóstico , Fragilidade/virologia , Avaliação Geriátrica/métodos , Pandemias , Pneumonia Viral , Idoso , Idoso de 80 Anos ou mais , Betacoronavirus , COVID-19 , China , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Estudos Prospectivos , SARS-CoV-2RESUMO
By screening a collection of Salmonella mutants deleted for genes encoding small proteins of ≤60 amino acids, we identified three paralogous small genes (ymdF, STM14_1829, and yciG) required for wild-type flagellum-dependent swimming and swarming motility. The ymdF, STM14_1829, and yciG genes encode small proteins of 55, 60, and 60 amino acid residues, respectively. A bioinformatics analysis predicted that these small proteins are intrinsically disordered proteins, and circular dichroism analysis of purified recombinant proteins confirmed that all three proteins are unstructured in solution. A mutant deleted for STM14_1829 showed the most severe motility defect, indicating that among the three paralogs, STM14_1829 is a key protein required for wild-type motility. We determined that relative to the wild type, the expression of the flagellin protein FliC is lower in the ΔSTM14_1829 mutant due to the downregulation of the flhDC operon encoding the FlhDC master regulator. By comparing the gene expression profiles between the wild-type and ΔSTM14_1829 strains via RNA sequencing, we found that the gene encoding the response regulator PhoP is upregulated in the ΔSTM14_1829 mutant, suggesting the indirect repression of the flhDC operon by the activated PhoP. Homologs of STM14_1829 are conserved in a wide range of bacteria, including Escherichia coli and Pseudomonas aeruginosa We showed that the inactivation of STM14_1829 homologs in E. coli and P. aeruginosa also alters motility, suggesting that this family of small intrinsically disordered proteins may play a role in the cellular pathway(s) that affects motility.IMPORTANCE This study reports the identification of a novel family of small intrinsically disordered proteins that are conserved in a wide range of flagellated and nonflagellated bacteria. Although this study identifies the role of these small proteins in the scope of flagellum-dependent motility in Salmonella, they likely play larger roles in a more conserved cellular pathway(s) that indirectly affects flagellum expression in the case of motile bacteria. Small intrinsically disordered proteins have not been well characterized in prokaryotes, and the results of our study provide a basis for their detailed functional characterization.
Assuntos
Proteínas de Bactérias/metabolismo , Flagelos/fisiologia , Proteínas Intrinsicamente Desordenadas/metabolismo , Locomoção , Salmonella enterica/fisiologia , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Dicroísmo Circular , Escherichia coli/genética , Escherichia coli/fisiologia , Deleção de Genes , Perfilação da Expressão Gênica , Proteínas Intrinsicamente Desordenadas/química , Proteínas Intrinsicamente Desordenadas/genética , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/fisiologia , Salmonella enterica/genéticaRESUMO
OBJECTIVE: To evaluate the value of shear wave elastography (SWE) in avoiding repeat fine-needle aspiration of thyroid nodules with nondiagnostic and undetermined cytology. METHODS: A total of 232 thyroid nodules with nondiagnostic (n = 132) and undetermined (n = 100) cytology underwent ultrasound (US) and SWE, followed by repeat ultrasound (US)-guided fine-needle aspiration cytology (FNAC). The final diagnosis was based on cytological or pathological findings. The US and SWE characteristics of benign and malignant nodules were compared using the χ2 -test. The receiver operating characteristic (ROC) curves of the thyroid imaging reporting and data system (TI-RADS) categories from the US and the EMean and ESD from the SWE were graphed, and the areas under the curves (AUCs) were compared using a Z test. RESULTS: There were significant differences between the benign and malignant nodules in terms of the echogenicity, shape, margin, calcification and TI-RADS categories (all P < 0.05). The differences were significant between the malignant and benign nodules for EMean [(34.57 ± 14.81) kPa vs. (19.18 ± 7.09) kPa] and ESD [(13.68 ± 13.01) kPa vs. (3.97 ± 2.58) kPa] (both P < 0.001). Though the difference in the AUCs of EMean (0.864) and ESD (0.876) was not significant (P = 0.745), they both had higher diagnostic performances in comparison with TI-RADS categories (0.762) (all P < 0.05). Moreover, ESD attained a sensitivity of 100% with a relatively higher specificity of 49.75% when its cut-off value was 3.3 kPa. CONCLUSIONS: Shear wave elastography is a promising imaging method for reducing repeat FNAC for benign thyroid nodules with nondiagnostic and undetermined cytology when using ESD as an index.
Assuntos
Biópsia por Agulha Fina/métodos , Técnicas de Imagem por Elasticidade/métodos , Glândula Tireoide/patologia , Neoplasias da Glândula Tireoide/patologia , Nódulo da Glândula Tireoide/diagnóstico por imagem , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Curva ROC , Estudos Retrospectivos , Adulto JovemRESUMO
Undaria pinnatifida sporophyll (U. pinnatifida) is a major byproduct of U. pinnatifida (a brown algae) processing. Its phenolic constituents, phlorotannins, are of special interest due to their intrinsic ability to precipitate proteins. Herein, a high-temperature extraction procedure was used to isolate these biologically active compounds. The heating temperature, heating time, and extraction solvent (ethanol) concentration were examined with response surface analysis to determine the optimal conditions to achieve the maximum extraction rate. The analysis revealed the optimal conditions to be: 170 °C of heating temperature, 5.2 h of heating time, and 52% ethanol concentration for a yield of 10.7 ± 0.2 mg gallic acid equivalent/g dry weight (GAE/g DW) of sample. Compared to epigallocatechin gallate (EGCG), the extracted phlorotannins displayed higher antioxidant activity on H2O2-induced RAW 264.7 cells with improved efficiency. Furthermore, the compounds exhibited strong anti-inflammatory activity. These findings potentially can be utilized to guide development of novel functional foods and food supplements from sea-originated resources such as brown algae.
Assuntos
Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Antioxidantes/química , Antioxidantes/fisiologia , Undaria/química , Animais , Linhagem Celular , Alimento Funcional , Camundongos , Phaeophyceae/química , Fenóis/química , Células RAW 264.7RESUMO
In pathogenic bacteria, the two-component regulatory systems (TCSs) play important roles in signal transduction and regulation of their pathogenesis. Here, we used quantitative proteomic methods to comparatively analyze functional networks under the control of the RstA/RstB system versus the PhoP/PhoQ system in Salmonella typhimurium. By comparing the proteomic profile from a wild-type strain to that from a ΔrstB strain or a ΔphoPQ strain under a condition known to activate these TCSs, we found that the levels of 159 proteins representing 6.92% of the 2297 proteins identified from the ΔrstB strain and 341 proteins representing 14.9% of the 2288 proteins identified from the ΔphoPQ strain were significantly changed, respectively. Bioinformatics analysis revealed that the RstA/RstB system and the PhoP/PhoQ system coordinated with regard to the regulation of specific proteins as well as metabolic processes. Our observations suggested that the regulatory networks controlled by the PhoP/PhoQ system were much more extensive than those by the RstA/RstB system, whereas the RstA/RstB system specifically regulated expression of the constituents participating in pyrimidine metabolism and iron acquisition. Additional results also suggested that the RstA/RstB system was required for regulation of Salmonella motility and invasion.
Assuntos
Salmonella typhimurium/genética , Salmonella typhimurium/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biologia Computacional , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Humanos , Ferro/metabolismo , Mutação , Proteômica , Pirimidinas/metabolismo , Salmonella typhimurium/patogenicidade , VirulênciaRESUMO
Riboswitches are a class of cis-acting regulatory RNAs normally characterized from the 5'-UTR of bacterial transcripts that bind a specific ligand to regulate expression of associated genes by forming alternative conformations. Here, we present a riboswitch that contributes to transcriptional regulation through sensing Mn(2+) in Salmonella typhimurium. We characterized a 5'-UTR (UTR1) from the mntH locus encoding a Mn(2+) transporter, which forms a Rho-independent terminator to implement transcription termination with a high Mn(2+) selectivity both in vivo and in vitro. Nucleotide substitutions that cause disruption of the terminator interfere with the regulatory function of UTR1. RNA probing analyses outlined a specific UTR1 conformation that favors the terminator structure in Mn(2+)-replete condition. Switch sequence GCUAUG can alternatively base pair duplicated hexanucleotide CAUAGC to form either a pseudoknot or terminator stem. Mn(2+), but not Mg(2+), and Ca(2+), can enhance cleavage at specific nucleotides in UTR1. We conclude that UTR1 is a riboswitch that senses cytoplasmic Mn(2+) and therefore participates in Mn(2+)-responsive mntH regulation in Salmonella. This riboswitch domain is also conserved in several Gram-negative enteric bacteria, indicating that this Mn(2+)-responsive mechanism could have broader implications in bacterial gene expression. Additionally, a high level of cytoplasmic Mn(2+) can down-regulate transcription of the Salmonella Mg(2+) transporter mgtA locus in a Mg(2+) riboswitch-dependent manner. On the other hand, these two types of cation riboswitches do not share similarity at the primary or secondary structural levels. Taken together, characterization of Mn(2+)-responsive riboswitches should expand the scope of RNA regulatory elements in response to inorganic ions.
Assuntos
Proteínas de Bactérias/biossíntese , Proteínas de Transporte de Cátions/biossíntese , Regulação Bacteriana da Expressão Gênica/fisiologia , Loci Gênicos/fisiologia , Manganês/metabolismo , Riboswitch/fisiologia , Salmonella typhimurium/metabolismo , Regiões 5' não Traduzidas/fisiologia , Adenosina Trifosfatases/biossíntese , Adenosina Trifosfatases/genética , Proteínas de Bactérias/genética , Cálcio/metabolismo , Proteínas de Transporte de Cátions/genética , Transporte de Íons/fisiologia , Magnésio/metabolismo , Proteínas de Membrana Transportadoras/biossíntese , Proteínas de Membrana Transportadoras/genética , Salmonella typhimurium/genéticaRESUMO
A genome-wide susceptibility assay was used to identify specific CpxR-dependent genes that facilitate Escherichia coli resistance to a model cationic antimicrobial peptide, protamine. A total of 115 strains from the Keio Collection, each of which contained a deletion at a demonstrated or predicted CpxR/CpxA-dependent locus, were tested for protamine susceptibility. One strain that exhibited high susceptibility carried a deletion of tolC, a gene that encodes the outer membrane component of multiple tripartite multidrug transporters. Concomitantly, two of these efflux systems, AcrAB/TolC and EmrAB/TolC, play major roles in protamine resistance. Activation of the CpxR/CpxA system stimulates mar transcription, suggesting a new regulatory circuit that enhances the multidrug resistance cascade. Tripartite multidrug efflux systems contribute to bacterial resistance to protamine differently from the Tat system. DNase I footprinting analysis demonstrated that the CpxR protein binds to a sequence located in the -35 and -10 regions of mar promoter. This sequence resembles the consensus CpxR binding site, however, on the opposite strand. aroK, a CpxR-dependent gene that encodes a shikimate kinase in the tryptophan biosynthesis pathway, was also found to facilitate protamine resistance. Specific aromatic metabolites from this pathway, such as indole, can stimulate expression of well studied CpxR-dependent genes degP and cpxP, which are not components of the tripartite multidrug transporters. Thus, we propose a novel mechanism for E. coli to modulate resistance to protamine and likely other cationic antimicrobial peptides in which the CpxR/CpxA system up-regulates mar transcription in response to specific aromatic metabolites, subsequently stimulating the multidrug resistance cascade.
Assuntos
Proteínas de Bactérias/metabolismo , Farmacorresistência Bacteriana Múltipla , Proteínas de Escherichia coli/metabolismo , Escherichia coli/efeitos dos fármacos , Protaminas/farmacologia , Proteínas Quinases/metabolismo , Peptídeos Catiônicos Antimicrobianos/farmacologia , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/metabolismo , Proteínas de Bactérias/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Viabilidade Microbiana/efeitos dos fármacos , Viabilidade Microbiana/genética , Modelos Genéticos , Mutação , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Regiões Promotoras Genéticas/genética , Ligação Proteica , Proteínas Quinases/genética , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Regulação para CimaRESUMO
We have characterized a 17-residue peptide, MgtL, which is translated specifically in high Mg(2+) from an open reading frame (ORF) embedded in the Mg(2+) riboswitch domain, previously identified in the 5' leader region of Mg(2+) transporter gene mgtA in Salmonella. We demonstrate that mgtL translation is required to prematurely terminate mgtA transcription. Abrogation of mgtL translation by mutation of its start codon results in transcription of the mgtA-coding region in high Mg(2+), suggesting that ribosome stalling is not required for preventing premature transcription termination. Consistently, the Mg(2+) riboswitch responds to cytoplasmic Mg(2+), but not to proline or arginine, both repeatedly present in the MgtL sequence, to mediate mgtL translation-coupled regulation. RNA structural probing and nucleotide substitution analysis show that the riboswitch loop A region alters base pairing in response to Mg(2+), and favours stem-loop A1 in high Mg(2+), subsequently opening the ribosome-binding sequence for mgtL translation. Presumably, mgtL ORF directs translation to localize a ribosome in cis to act on downstream RNA in a manner similar to some upstream ORFs in prokaryotes and eukaryotes.
Assuntos
Magnésio/farmacologia , Terminação Traducional da Cadeia Peptídica/efeitos dos fármacos , Sinais Direcionadores de Proteínas/genética , Ribossomos/fisiologia , Riboswitch/fisiologia , Transcrição Gênica/efeitos dos fármacos , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sequência de Bases , Códon de Iniciação , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Fases de Leitura Aberta , Salmonella typhimurium/genética , Salmonella typhimurium/crescimento & desenvolvimento , Salmonella typhimurium/metabolismo , Homologia de Sequência de Aminoácidos , Homologia de Sequência do Ácido NucleicoRESUMO
BACKGROUND: We previously showed that impulse oscillometry (IOS) indices of peripheral airway function are associated with asthma control in children. However, little data exist on whether dysfunction in the peripheral airways can predict loss of asthma control. OBJECTIVE: We sought to determine the utility of peripheral airway impairment, as measured by IOS, in predicting loss of asthma control in children. METHODS: Fifty-four children (age, 7-17 years) with controlled asthma were enrolled in the study. Spirometric and IOS indices of airway function were obtained at baseline and at a follow-up visit 8 to 12 weeks later. Physicians who were blinded to the IOS measurements assessed asthma control (National Asthma Education and Prevention Program guidelines) on both visits and prescribed no medication change between visits. RESULTS: Thirty-eight (70%) patients maintained asthma control between 2 visits (group C-C), and 16 patients had asthma that became uncontrolled on the follow-up visit (group C-UC). There was no difference in baseline spirometric results between the C-C and C-UC groups, except for FEV1/forced vital capacity ratio (86% vs 82%, respectively; P < .01). Baseline IOS results, including resistance of the respiratory system at 5 Hz (R5; 6.4 vs 4.3 cm H2O · L(-1) · s), frequency dependence of resistance (difference of R5 and resistance of the respiratory system at 20 Hz [R5-20]; 2.0 vs 0.7 cm H2O · L(-1) · s), and reactance area (13.1 vs 4.1 cm H2O · L(-1)), of group C-UC were significantly higher than those of group C-C (P < .01). Receiver operating characteristic analysis showed baseline R5-20 and reactance area effectively predicted asthma control status at the follow-up visit (area under the curve, 0.91 and 0.90). CONCLUSION: Children with controlled asthma who have increased peripheral airway IOS indices are at risk of losing asthma control.
Assuntos
Resistência das Vias Respiratórias , Asma/fisiopatologia , Adolescente , Asma/diagnóstico , Criança , Feminino , Humanos , Pulmão/fisiopatologia , Masculino , Oscilometria , EspirometriaRESUMO
BACKGROUND: Pesticide efficacy directly affects crop yield and quality, making targeted spraying a more environmentally friendly and effective method of pesticide application. Common targeted cabbage spraying methods often involve object detection networks. However, complex natural and lighting conditions pose challenges in the accurate detection and positioning of cabbage. RESULTS: In this study, a cabbage detection algorithm based on the YOLOv8n neural network (YOLOv8-cabbage) combined with a positioning system constructed using a Realsense depth camera is proposed. Initially, four of the currently available high-performance object detection models were compared, and YOLOv8n was selected as the transfer learning model for field cabbage detection. Data augmentation and expansion methods were applied to extensively train the model, a large kernel convolution method was proposed to improve the bottleneck section, the Swin transformer module was combined with the convolutional neural network (CNN) to expand the perceptual field of feature extraction and improve edge detection effectiveness, and a nonlocal attention mechanism was added to enhance feature extraction. Ablation experiments were conducted on the same dataset under the same experimental conditions, and the improved model increased the mean average precision (mAP) from 88.8% to 93.9%. Subsequently, depth maps and colour maps were aligned pixelwise to obtain the three-dimensional coordinates of the cabbages via coordinate system conversion. The positioning error of the three-dimensional coordinate cabbage identification and positioning system was (11.2 mm, 10.225 mm, 25.3 mm), which meets the usage requirements. CONCLUSIONS: We have achieved accurate cabbage positioning. The object detection system proposed here can detect cabbage in real time in complex field environments, providing technical support for targeted spraying applications and positioning.
RESUMO
Retinal disease has become the major cause of visual impairment and vision loss worldwide. Carotenoids, which have the potential antioxidant and eye-care activities, have been widely used in functional foods. Our previous study showed that fucoxanthin could exert photoprotective activity in UVB-induced retinal müller cells (RMCs). To extend the application of fucoxanthin in food industry, fucoxanthin, Undaria pinnatifida pulp (UPP), carrageenan, and other ingredients were mixed to prepare seaweed-flavoured photoprotective gummies in this study. The structural and functional properties of the gummies were then evaluated by physicochemical test and cell experiments. As a result, fucoxanthin enriched gummies presented favourable structural properties and flavour. The hydroxyl groups in fucoxanthin and κ-carrageenan are bonded through hydrogen bonds, forming the spatial network structure inside the gummies, enhancing its elasticity. The gummies showed significant antioxidant effect and alleviated the UVB oxidation damage in RMCs. Moreover, the main ingredients carrageenan and UPP improved the stability of fucoxanthin during in vitro digestion. The results enhance the application of fucoxanthin in functional food with photoprotective activity.