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BACKGROUND: Racial and ethnic disparities in mortality persist among US cancer survivors, with social determinants of health (SDoH) may have a significant impact on these disparities. METHODS: A population-based cohort study of a nationally representative sample of adult cancer survivors, who participated in the US National Health and Nutrition Examination Survey from 1999 to 2018 was included. Sociodemographic characteristics and SDoH were self-reported using standardized questionnaires in each survey cycle. The SDoH was examined by race and estimated for associations with primary outcomes, which included all-cause and cancer-specific mortality. Multiple mediation analysis was performed to assess the contribution of each unfavorable SDoH to racial disparities to all-cause and cancer-specific mortality. RESULTS: Among 5163 cancer survivors (2724 [57.7%] females and 3580 [69.3%] non-Hispanic White individuals), only 881 (24.9%) did not report an unfavorable SDoH. During the follow-up period of up to 249 months (median 81 months), 1964 deaths were recorded (cancer, 624; cardiovascular, 529; other causes, 811). Disparities in all-cause and cancer-specific mortality were observed between non-Hispanic Black and White cancer survivors. Unemployment, lower economic status, education less than high school, government or no private insurance, renting a home or other arrangements, and social isolation were significantly and independently associated with worse overall survival. Unemployment, lower economic status, and social isolation were significantly associated with cancer-specific mortality. Compared to patients without an unfavorable SDoH, the risk of all-cause mortality was gradually increased in those with a cumulative number of unfavorable SDoHs (1 unfavorable SDoH: hazard ratio [HR] = 1.54, 95% CI 1.25-1.89; 2 unfavorable SDoHs: HR = 1.81, 95% CI 1.46-2.24; 3 unfavorable SDoHs: HR = 2.42, 95% CI 1.97-2.97; 4 unfavorable SDoHs: HR = 3.22, 95% CI 2.48-4.19; 5 unfavorable SDoHs: HR = 3.99, 95% CI 2.99-5.33; 6 unfavorable SDoHs: HR = 6.34 95% CI 4.51-8.90). A similar trend existed for cancer-specific mortality. CONCLUSIONS: In this cohort study of a nationally representative sample of US cancer survivors, a greater number of unfavorable SDoH was associated with increased risks of mortality from all causes and cancer. Unfavorable SDoH levels were critical risk factors for all-cause and cancer-specific mortality, as well as the underlying cause of racial all-cause mortality disparities among US cancer survivors.
Assuntos
Sobreviventes de Câncer , Determinantes Sociais da Saúde , Humanos , Feminino , Sobreviventes de Câncer/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Estados Unidos/epidemiologia , Adulto , Idoso , Estudos de Coortes , Neoplasias/mortalidade , Disparidades nos Níveis de Saúde , Fatores Socioeconômicos , Análise de SobrevidaRESUMO
BACKGROUND: Glioblastoma multiforme (GBM) is the most aggressive form of brain cancer, and chemoresistance poses a significant challenge to the survival and prognosis of GBM. Although numerous regulatory mechanisms that contribute to chemoresistance have been identified, many questions remain unanswered. This study aims to identify the mechanism of temozolomide (TMZ) resistance in GBM. METHODS: Bioinformatics and antibody-based protein detection were used to examine the expression of E2F7 in gliomas and its correlation with prognosis. Additionally, IC50, cell viability, colony formation, apoptosis, doxorubicin (Dox) uptake, and intracranial transplantation were used to confirm the role of E2F7 in TMZ resistance, using our established TMZ-resistance (TMZ-R) model. Western blot and ChIP experiments provided confirmation of p53-driven regulation of E2F7. RESULTS: Elevated levels of E2F7 were detected in GBM tissue and were correlated with a poor prognosis for patients. E2F7 was found to be upregulated in TMZ-R tumors, and its high levels were linked to increased chemotherapy resistance by limiting drug uptake and decreasing DNA damage. The expression of E2F7 was also found to be regulated by the activation of p53. CONCLUSIONS: The high expression of E2F7, regulated by activated p53, confers chemoresistance to GBM cells by inhibiting drug uptake and DNA damage. These findings highlight the significant connection between sustained p53 activation and GBM chemoresistance, offering the potential for new strategies to overcome this resistance.
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Neoplasias Encefálicas , Glioblastoma , Humanos , Antineoplásicos Alquilantes/farmacologia , Antineoplásicos Alquilantes/uso terapêutico , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos/genética , Fator de Transcrição E2F7/metabolismo , Glioblastoma/tratamento farmacológico , Glioblastoma/genética , Glioblastoma/metabolismo , Prognóstico , Temozolomida/farmacologia , Temozolomida/uso terapêutico , Proteína Supressora de Tumor p53/genéticaRESUMO
Investigating novel nonlinear optical (NLO) active units serves as a valuable method for broadening the research landscape of NLO materials. This study showcases the potential of the cytosinium cation (C4H6N3O)+ as a novel NLO-active motif through theoretical calculations. The title compound exhibited a wide band gap of 3.85 eV, along with a moderate second harmonic generation (SHG) response of 1.65 times that of KH2PO4 (KDP) and significant birefringence of 0.47. Its exceptional optical properties are primarily attributed to the synergy interaction between cations and anionic groups in the asymmetric unit.
RESUMO
The key to searching novel nonlinear optical (NLO) crystals was effectively combining the NLO-active units to obtain a noncentrosymmetric structure. Nevertheless, the present predicament lies in the growing challenge of discovering novel crystals within conventional inorganic frameworks that surpass the properties of the current NLO materials. In view of this, researchers expanded their research focus to the organic-inorganic hybridization system; it is foreseeable to concentrate the advantages from several kinds of NLO-active units to acquire novel NLO crystals with superior properties. We herein report an organic-inorganic hybrid molybdate crystal, namely, [C(NH2)3]6Mo7O24 (GMO). It was successfully obtained via combining inorganic NLO-active MoO6 octahedra and organic π-conjugated [C(NH2)3]+ groups. GMO demonstrates a moderate second-harmonic-generation response, specifically measuring about 1.3 times the value of KDP. Additionally, it exhibits a significant birefringence value of 0.203 at the wavelength of 550 nm and possesses a wide band gap of 3.31 eV. Theoretical calculations suggest that the optical properties of the GMO are primarily influenced by the synergy effect of [C(NH2)3]+ groups between MoO6 octahedra.
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We herein report an unprecedented organic-inorganic hybrid borate incorporating a novel nonlinear-optical (NLO) active unit, namely, [C(NH2)3][B(C2O2H4)2]. The novel NLO active unit was derived from the condensation reaction between two glycol molecules and one (BO4)5- group. The title compound exhibits a moderate second-harmonic-generation effect (0.7 × KDP), a significant band gap (5.76 eV), and a suitable birefringence (0.078 at 550 nm). The optical properties are determined by the synergistic interaction between the C(NH2)3+ cation and the [B(C2O2H4)2]- group, as indicated by theoretical calculations.
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Recently, we re-isolated the glycosylated angucycline antibiotics P-1894B (1) and grincamycin (1') from the marine-derived Streptomyces lusitanus SCSIO LR32 as potent antitumor agents and identified their biosynthesis gene cluster gcn. Both P-1894B (1) and grincamycin (1') possess a trisaccharide and a disaccharide moiety comprised of five deoxysugars. In this work, three genes encoding glycosyltransferases (GcnG1, GcnG2, and GcnG3) responsible for the assembly of deoxysugars into angucycline aglycone were identified from the biosynthesis gene cluster gcn. Gene inactivations of gcnG1, gcnG2, gcnG3, and gcnG1G2 by lambda-RED-mediated gene replacements led to the construction of four mutants, in which the glycosyltransferase genes were disrupted, respectively. The metabolites from the mutants were purified and identified, including two new analogues designated as grincamycin U (3a) and V (3'). The sequential glycosylation steps in the biosynthesis of P-1894B (1) and grincamycin (1') catalyzed by GcnG3, GcnG1, and GcnG2 were elucidated.
Assuntos
Antraquinonas , Streptomyces , GlicosilaçãoRESUMO
Natural minerals, with their adaptable framework structures exemplified by perovskite and lyonsite, have sparked substantial interest as potential templates for the design of advanced functional solid-state materials. Nonetheless, the quest for new materials with desired properties remains a substantial challenge, primarily due to the scarcity of effective and practical synthetic approaches. In this study, we have harnessed a synergistic approach that seamlessly integrates first-principles high-throughput screening and crystal engineering to reinvigorate the often-overlooked fresnoite mineral, Ba2 TiOSi2 O7 . This innovative strategy has culminated in the successful synthesis of two superior inorganic UV nonlinear optical materials, namely Rb2 TeOP2 O7 and Rb2 SbFP2 O7 . Notably, Rb2 SbFP2 O7 demonstrates a comprehensive enhancement in nonlinear optical performance, featuring a shortened UV absorption edge (260â nm) and a more robust second-harmonic generation response (5.1×KDP). Particularly striking is its significantly increased birefringence (0.15@546â nm), which is approximately 30 times higher than the prototype Ba2 TiOSi2 O7 (0.005@546â nm). Our research has not only revitalized the potential of the fresnoite mineral for the development of new high-performance UV nonlinear optical materials but has also provided a clearly defined roadmap for the efficient exploration of novel structure-driven functional materials with targeted properties.
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Fluorine-containing borate crystal materials are particularly attractive due to their rich structural chemistry and excellent properties for optical applications. In this work, a new compound Ba3.75MgB7O14F2.5 has been synthesized through the high-temperature solution method. In the crystal structure of Ba3.75MgB7O14F2.5, the [B7O14] basic building unit and the [MgO3F3] octahedra are interconnected to create a complex three-dimensional network. The structural feature of the less commonly observed [B7O14] units is discussed, and it has been found that such units in Ba3.75MgB7O14F2.5 are most conducive to achieving large birefringence. In addition, Ba3.75MgB7O14F2.5 exhibits good thermal stability, a short ultraviolet cutoff of 203 nm, and large birefringence (0.081@546 nm), indicating its potential as a new UV birefringent crystal.
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We herein report a mixed organic cationic hybrid nitrate, namely, [C(NH2)2NHNO2][C(NH2)3](NO3)2 (1). It was successfully achieved via combining three different planar groups: [(C(NH2)2NHNO2]+, C(NH2)3+, and NO3-. First-principles calculations confirm that the [(C(NH2)2NHNO2]+ group is an excellent cationic nonlinear-optical (NLO)-active unit. The title compound exhibits a moderate second-harmonic-generation (SHG) response (1.5 × KDP), a wide band gap (3.58 eV), and a suitable birefringence of 0.071 at 550 nm. Theoretical calculations indicate that the synergy effect between the [(C(NH2)2NHNO2]+ and C(NH2)3+ groups dominates the SHG process.
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Atherosclerosis (AS) is an essential pathological changes of ischemic cardio-cerebrovascular disease, and monocyte migration and adhesion to endothelial cells are the critical pathological process in AS. Our previous studies demonstrated a beneficial effect of zedoarondiol in AS, but whether the mechanism is associated with monocyte migration and adhesion to endothelial cells remains unclear. In this study, we investigated whether the anti-atherosclerotic effects of zedoarondiol were associated with decreasing migration and adhesion of monocytes. The oil red O staining demonstrated that zedoarondiol ameliorated AS plaques in en face aorta and aortic root of apolipoprotein E gene knocked (apoE-/-) mice. In vitro, zedoarondiol decreased human monocytic macrophage-like cell line (THP-1) monocytes migration and adhesion to endothelial cells. Single-cell RNA sequencing analysis (scRNA-seq) in mice indicated that zedoarondiol decreased monocytes adhesion to endothelial cells by regulating CXC chemokine ligand 12/CXC chemokine receptor 4 (CXCL12/CXCR4) pathway, which was verified by Western blot of THP-1 monocytesï¼zedoarondiol also decreased the expressions of phosphoinositide 3-kinase (PI3K), protein kinase B (AKT) and nuclear factor-kappa B (NF/κB), the downstream proteins of CXCL12/CXCR4 pathway. In conclusion, zedoarondiol ameliorated AS plaque and inhibited monocyte migration and adhesion to endothelial cells via regulating CXCL12/CXCR4 pathway, suggesting that zedoarondiol might be a new promising drug for AS.
Assuntos
Aterosclerose , Placa Aterosclerótica , Animais , Aterosclerose/metabolismo , Adesão Celular , Quimiocina CXCL12/metabolismo , Células Endoteliais/metabolismo , Humanos , Lactonas , Camundongos , Monócitos/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Placa Aterosclerótica/tratamento farmacológico , Placa Aterosclerótica/metabolismo , Receptores CXCR4/metabolismo , SesquiterpenosRESUMO
The outbreak and persistence of coronavirus disease 2019 (COVID-19) threaten human health. B cells play a vital role in fighting the infections caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Despite many studies on the immune responses in COVID-19 patients, it is still unclear how B cell receptor (BCR) constituents, including immunoglobulin heavy (IGHs) and light chains (IGLs), respond to SARS-CoV-2 in patients with varying symptoms. In this study, we conducted complementarity-determining region 3 (CDR3) sequencing of BCR IGHs and IGLs from the peripheral blood of COVID-19 patients and healthy donors. The results showed significantly reduced clonal diversity, more expanded clones, and longer CDR3 lengths of IGH and IGL in COVID-19 patients than those in healthy individuals. The IGLs had a much higher percentage of VJ skew usage (47.83% IGLV and 42.86% IGLJ were significantly regulated) than the IGHs (12.09% IGHV and 0% IGHJ) between the healthy individuals and patients, which indicated the importance of BCR light chains. Furthermore, we found a largely expanded IGLV3-25 gene cluster mostly pairing with IGLJ1 and ILGJ2 in COVID-19 patients and a newly identified upregulated IGLJ1 gene and IGLJ2+IGLV13-21 recombination, both of which are potential sources of SARS-CoV-2-targeting antibodies. Our findings on specific immune B-cell signatures associated with COVID-19 have clinical implications for vaccine and biomarker development for disease diagnosis.
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COVID-19 , Regiões Determinantes de Complementaridade , Linfócitos B , COVID-19/genética , Regiões Determinantes de Complementaridade/genética , Humanos , Receptores de Antígenos de Linfócitos B/genética , SARS-CoV-2RESUMO
Two new phthalide derivatives (1-2) and four known phthalide compounds (3-6) were purified from the culture of a mangrove endophytic fungus Pestalotiopsis sp. SAS4. Their chemical structures were established by analyses of 1D and 2D nuclear magnetic resonance (NMR) and high resolution mass spectrometry (HR-MS) spectroscopic data. All of these compounds were evaluated in vitro for antibacterial, cytotoxicity, and resistance to hypoxic-ischemic injury activities.
Assuntos
Benzofuranos , Pestalotiopsis , Benzofuranos/química , Benzofuranos/farmacologia , Fungos , Estrutura MolecularRESUMO
BACKGROUND: Proteinuria is one of the common manifestations of patients with preeclampsia (PE), but whether the severity of proteinuria is related to the pregnancy outcome of patients with preeclampsia remains controversial. The present study aimed to determine the relationship between 24-h proteinuria and adverse outcomes in patients with preeclampsia. METHODS: The present retrospective study included 329 pregnant women in Chongqing, China. Patients were divided into PE group and non-PE group. PE group was stratified into three subgroups based on the level of 24-h proteinuria. Correlation analysis was used to analyze the correlation between biochemical indexes and adverse pregnancy outcome, and Logistic regression analysis was used to analyze the risk factors of adverse pregnancy outcome. The receiver operating characteristic curve (ROC) was used to evaluate the ability of 24-h urinary protein to distinguish the adverse pregnancy outcome in patients with preeclampsia. RESULTS: (1) Between PE and non-PE group, cesarean section rate in PE group was significantly higher than that in non-PE group (84.4% vs. 25.9%, p < 0.001). Laboratory findings such as uric acid and creatinine level in PE group were higher than those in non-PE group. (2) Among mild (proteinuria < 0.3 g/24 h), moderate (0.3 g/24 h ⦠proteinuria < 2 g/24 h) and massive (proteinuria ⧠2 g/24 h) groups, the frequencies of induced labor (p = 0.006) and stillbirth (p = 0.002) increased with the increase of 24-h proteinuria. (3) Adverse outcomes were positively correlated with 24-h proteinuria (adverse maternal outcomes: r = 0.239, p = 0.002; adverse fetal outcomes: r = 0.336, p < 0.001). (4) The best 24-h proteinuria cutoff values to determine stillbirth, premature and fetal distress were 3965.0 mg/24 h, 984.75 mg/24 h and 1503.85 mg/24 h and their odds ratio (95% confidence interval) were 12.46 (3.46-44.88), 2.48 (1.15-5.37) and 10.02 (2.14-46.80), respectively. CONCLUSIONS: The severity of 24-h proteinuia may forecast adverse outcomes in women with preeclampsia. We suggest proteinuria should be retained as one of the monitoring indexes in patients with preeclampsia. TRIAL REGISTRATION: Retrospectively registered. (LTMCMTS202001).
Assuntos
Pré-Eclâmpsia/urina , Resultado da Gravidez , Proteinúria/etiologia , Adulto , Área Sob a Curva , Peso ao Nascer , Cesárea/estatística & dados numéricos , Parto Obstétrico/estatística & dados numéricos , Feminino , Humanos , Recém-Nascido , Doenças do Recém-Nascido/epidemiologia , Modelos Logísticos , Gravidez , Complicações na Gravidez/epidemiologia , Utilização de Procedimentos e Técnicas , Proteinúria/epidemiologia , Curva ROC , Estudos Retrospectivos , Fatores de RiscoRESUMO
Grincamycins (GCNs) are a class of angucycline glycosides isolated from actinomycete Streptomyces strains that have potent antitumor activities, but their antitumor mechanisms remain unknown. In this study, we tried to identify the cellular target of grincamycin B (GCN B), one of most dominant and active secondary metabolites, using a combined strategy. We showed that GCN B-selective-induced apoptosis of human acute promyelocytic leukemia (APL) cell line NB4 through increase of ER stress and intracellular reactive oxygen species (ROS) accumulation. Using a strategy of combining phenotype, transcriptomics and protein microarray approaches, we identified that isocitrate dehydrogenase 1(IDH1) was the putative target of GCN B, and confirmed that GCNs were a subset of selective inhibitors targeting both wild-type and mutant IDH1 in vitro. It is well-known that IDH1 converts isocitrate to 2-oxoglutarate (2-OG), maintaining intracellular 2-OG homeostasis. IDH1 and its mutant as the target of GCN B were validated in NB4 cells and zebrafish model. Knockdown of IDH1 in NB4 cells caused the similar phenotype as GCN B treatment, and supplementation of N-acetylcysteine partially rescued the apoptosis caused by IDH1 interference in NB4 cells. In zebrafish model, GCN B effectively restored myeloid abnormality caused by overexpression of mutant IDH1(R132C). Taken together, we demonstrate that IDH1 is one of the antitumor targets of GCNs, suggesting wild-type IDH1 may be a potential target for hematological malignancies intervention in the future.
Assuntos
Antraquinonas/farmacologia , Antineoplásicos/farmacologia , Inibidores Enzimáticos/farmacologia , Glicosídeos/farmacologia , Isocitrato Desidrogenase/antagonistas & inibidores , Animais , Antraquinonas/metabolismo , Antineoplásicos/metabolismo , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Inibidores Enzimáticos/metabolismo , Glicosídeos/metabolismo , Humanos , Isocitrato Desidrogenase/genética , Isocitrato Desidrogenase/metabolismo , Ácidos Cetoglutáricos/metabolismo , Simulação de Acoplamento Molecular , Mutação , Ligação Proteica , Espécies Reativas de Oxigênio/metabolismo , Peixe-ZebraRESUMO
Therapeutic agents that target both tumor cell and vascular endothelial cell may achieve additional anti-tumor efficacy, particularly in lung cancer due to the critical roles of angiogenesis during lung cancer progression and metastasis. In this work, we showed that pitavastatin, a novel cholesterol-lowering drug, potently inhibited lung cancer cells and angiogenesis. This was achieved by the induction of apoptosis and inhibition of proliferation of lung cancer cells and human lung tumor-associated endothelial cell. Pitavastatin was not only effective to chemo-sensitive but also chemo-resistant lung cancer cells. This was also consistent with the finding that pitavastatin significantly enhanced cisplatin's efficacy in lung cancer xenograft model without causing toxicity in mice. We further showed that pitavastatin inhibited lung tumor angiogenesis in vitro and in vivo through suppressing human lung tumor-associated endothelial cell migration and morphogenesis without affecting adhesion. Mechanistically, we showed that pitavastatin acted on lung cancer cells and human lung tumor-associated endothelial cell through suppressing prenylation-dependent Ras/Raf/MEK and PI3K/Akt/mTOR signaling. Our work is the first to demonstrate the inhibitory effects of pitavastatin on Ras-mediated signaling. Our findings provide pre-clinical evidence to repurpose pitavastatin for the treatment of lung cancer.
Assuntos
Biomarcadores Tumorais/metabolismo , Colesterol/metabolismo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Neoplasias Pulmonares/tratamento farmacológico , Neovascularização Patológica/tratamento farmacológico , Prenilação , Quinolinas/farmacologia , Animais , Apoptose , Biomarcadores Tumorais/genética , Proliferação de Células , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Neoplasias Pulmonares/irrigação sanguínea , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , MAP Quinase Quinase 1/genética , MAP Quinase Quinase 1/metabolismo , Camundongos , Camundongos SCID , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas c-raf/genética , Proteínas Proto-Oncogênicas c-raf/metabolismo , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismo , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto , Proteínas ras/genética , Proteínas ras/metabolismoRESUMO
Galactose, a monosaccharide capable of assuming two possible configurational isomers (d-/l-), can exist as a six-membered ring, galactopyranose (Galp), or as a five-membered ring, galactofuranose (Galf). UDP-galactopyranose mutase (UGM) mediates the conversion of pyranose to furanose thereby providing a precursor for d-Galf Moreover, UGM is critical to the virulence of numerous eukaryotic and prokaryotic human pathogens and thus represents an excellent antimicrobial drug target. However, the biosynthetic mechanism and relevant enzymes that drive l-Galf production have not yet been characterized. Herein we report that efforts to decipher the sugar biosynthetic pathway and tailoring steps en route to nucleoside antibiotic A201A led to the discovery of a GDP-l-galactose mutase, MtdL. Systematic inactivation of 18 of the 33 biosynthetic genes in the A201A cluster and elucidation of 10 congeners, coupled with feeding and in vitro biochemical experiments, enabled us to: (i) decipher the unique enzyme, GDP-l-galactose mutase associated with production of two unique d-mannose-derived sugars, and (ii) assign two glycosyltransferases, four methyltransferases, and one desaturase that regiospecifically tailor the A201A scaffold and display relaxed substrate specificities. Taken together, these data provide important insight into the origin of l-Galf-containing natural product biosynthetic pathways with likely ramifications in other organisms and possible antimicrobial drug targeting strategies.
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Actinobacteria/metabolismo , Aminoglicosídeos/biossíntese , Proteínas de Bactérias/metabolismo , Açúcares de Guanosina Difosfato/metabolismo , Transferases Intramoleculares/metabolismo , Actinobacteria/genética , Aminoglicosídeos/genética , Proteínas de Bactérias/genética , Açúcares de Guanosina Difosfato/genética , Transferases Intramoleculares/genéticaRESUMO
The antimicrobial nucleoside antibiotic A201A is produced by the deep-sea derived Marinactinospora thermotolerans SCSIO 00652. Bioinformatics analysis revealed that mtdV, downstream within the A201A biosynthetic gene cluster, encodes a protein with low homology to a group of chorismate pyruvate-lyases. To explore the role of mtdV in A201A biosynthesis, mtdV was inactivated and HPLC analysis revealed that the resulting ΔmtdV mutant failed to produce A201A; production was partially restored by adding exogenous 4-hydroxybenzoic acid (4HB) to the fermentation. In vitro biochemical assays showed that MtdV catalyzes the conversion of chorismate into 4HB, thereby firmly demonstrating that MtdV is a chorismate lyase involved in A201A biosynthesis. In addition, supplementation of the ΔmtdV mutant with various 4HB analogs enabled production of seven new A201A analogs. Antimicrobial assays showed that the purified A201A analogs 3'-F-A201A and 3'-Cl-A201A were just as active as A201A against the test strains with MIC values of 1-8 µg mL-1.
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Actinobacteria/enzimologia , Aminoglicosídeos/biossíntese , Oxo-Ácido-Liases/metabolismo , Aminoglicosídeos/química , Biocatálise , Biologia Computacional , Estrutura Molecular , Mutação , Oxo-Ácido-Liases/genéticaRESUMO
Four new hydroxamate-containing natural product cyclopeptides designated acremonpeptides A-D (1-4), together with Al(III)-acremonpeptide D (5) were obtained from the marine fungus Acremonium persicinum SCSIO 115. The planar structures of 1-5 were established on the basis of HRMS as well as 1D and 2D NMR data sets. Moreover, the amino acid absolute configurations were determined using Marfey's method. Compounds 1-5 all feature three 2-amino-5-(N-hydroxyacetamido)pentanoic acid (N5-hydroxy-N5-acetyl-l-ornithine) metal ion chelating moieties. Beyond their discovery and structure elucidation, in vitro bioassays revealed acremonpeptides A (1), B (2), and Al(III)-acremonpeptide D (5) as moderate antiviral agents for herpes simplex virus 1 with EC50 values of 16, 8.7, and 14 µM, respectively.
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Acremonium/química , Alumínio/química , Biologia Marinha , Sideróforos/químicaRESUMO
Bacillus spp. are important producers of bioactive natural products with potential applications in medicine and agriculture. Bacillus sp. SCSIO 05476 from a deep-sea sediment exhibits broad-spectrum antimicrobial activities and strong cytotoxic activity. Here, an integrative approach combining genome mining and metabolic profiling has been applied to decipher the chemical origins of this strain's varied and significant biological activities. First, genome mining revealed 19 candidate gene clusters encoding the biosynthesis of diverse secondary metabolites. Then, a series of bacillibactins, fengycins, bacillomycins, surfactins, bacillaenes, macrolactins, and related species were found by LC-DAD-MS. Finally, three new linear bacillibactins, linbacillibactins A-C (1-3), along with 11 known secondary metabolites, bacillibactin (4), normal-C13 Val7 surfactin (5), anteiso-C13 Leu7 surfactin (6), iso-C14 Leu7 surfactin (7), normal-C14 Leu7 surfactin (8), anteiso-C14 Leu7 surfactin (9), macrolactin D (10), normal-C14 bacillomycin D (11), iso-C16 bacillomycin D (12), normal-C17 bacillomycin D (13), and iso-C17 bacillomycin D (14), were obtained and elucidated by bioactivity and structure-guided isolation from the fermentation of strain SCSIO 05746. Among them, new compounds 1-3 show significant siderophore activities comparable to that of bacillibactin (4), compounds 13 and 14 exhibit strong cytotoxic activity. At the same time, the strain classification status was confirmed by genomic analyses, and the complete genome sequence of Bacillus siamensis was presented firstly. This study provides a foundation for understanding the mechanisms driving SCSIO 05746's multiple bioactivities and demonstrates a successful way of discovering bioactive metabolites using a combination of genome mining and metabolic profiling methods.
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Bacillus/química , Produtos Biológicos/análise , Genoma Bacteriano , Genômica , Redes e Vias Metabólicas/genética , Metabolômica , Bacillus/genética , Mineração de DadosRESUMO
The topological transport of Lamb wave in phononic crystal slabs provides a great potential in reinforcing nondestructive testing, high sensitivity sensing, and information processing. In this paper, the authors investigate the pseudospins edge states of fundamental antisymmetric Lamb waves in a snowflakelike phononic slab. Significantly, the fourfold Dirac degeneracy for antisymmetric Lamb mode is accidentally formed at the Γ point with the critical angle of the snowflakelike holes, which does not require the folding of the lattices. Meanwhile, based on the rotating-scatterer mechanism, the mirror symmetry is broken and the topological multipole phase transitions are well induced during the gradual change of the scattering strength among the scatterers with the rotation angle. The topologically protected edge states and its unidirectional robust propagation are further demonstrated. The proposed topological phononic slabs will be a more hopeful option to apply in engineering practices.