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1.
Nucleic Acids Res ; 50(5): 2417-2430, 2022 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-35191495

RESUMO

Two families of DNA glycosylases (YtkR2/AlkD, AlkZ/YcaQ) have been found to remove bulky and crosslinking DNA adducts produced by bacterial natural products. Whether DNA glycosylases eliminate other types of damage formed by structurally diverse antibiotics is unknown. Here, we identify four DNA glycosylases-TxnU2, TxnU4, LldU1 and LldU5-important for biosynthesis of the aromatic polyketide antibiotics trioxacarcin A (TXNA) and LL-D49194 (LLD), and show that the enzymes provide self-resistance to the producing strains by excising the intercalated guanine adducts of TXNA and LLD. These enzymes are highly specific for TXNA/LLD-DNA lesions and have no activity toward other, less stable alkylguanines as previously described for YtkR2/AlkD and AlkZ/YcaQ. Similarly, TXNA-DNA adducts are not excised by other alkylpurine DNA glycosylases. TxnU4 and LldU1 possess unique active site motifs that provide an explanation for their tight substrate specificity. Moreover, we show that abasic (AP) sites generated from TxnU4 excision of intercalated TXNA-DNA adducts are incised by AP endonuclease less efficiently than those formed by 7mG excision. This work characterizes a distinct class of DNA glycosylase acting on intercalated DNA adducts and furthers our understanding of specific DNA repair self-resistance activities within antibiotic producers of structurally diverse, highly functionalized DNA damaging agents.


Assuntos
Adutos de DNA , DNA Glicosilases , Aminoglicosídeos , Antibacterianos/farmacologia , Dano ao DNA , DNA Glicosilases/metabolismo , Reparo do DNA
2.
Cell Commun Signal ; 21(1): 155, 2023 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-37370070

RESUMO

BACKGROUND: Coronary artery disease (CAD) is a multi-factor complex trait and is heritable, especially in early-onset families. However, the genetic factors affecting the susceptibility of early-onset CAD are not fully characterized. METHODS: In the present study, we identified a rare nonsense variant in the CYP17A1 gene from a Chinese Han family with CAD. To validate the effect of this variation on atherosclerosis and early-onset coronary artery disease, we conducted studies on population, cells, and mice. RESULTS: The mutation precisely congregated with the clinical syndrome in all the affected family members and was absent in unaffected family members and unrelated controls. Similar to the human phenotype, the CYP17A1-deficient mice present the phenotype of metabolic syndrome with hypertension, increased serum glucose concentration, and presentation of central obesity and fatty liver. Furthermore, CYP17A1 knockout mice or CYP17A1 + ApoE double knockout mice developed more atherosclerotic lesions than wild type (WT) with high fat diary. In cell models, CYP17A1 was found to be involved in glucose metabolism by increasing glucose intake and utilization, through activating IGF1/mTOR/HIF1-α signaling way, which was consistent in CYP17A1 knockout mice with impaired glucose tolerance and insulin resistance. CONCLUSIONS: Through our study of cells, mice and humans, we identified CYP17A1 as a key protein participating in the pathophysiology of the atherosclerotic process and the possible mechanism of CYP17A1 C987X mutation induced atherosclerosis and early-onset CAD involving glucose homeostasis regulation was revealed. Video Abstract.


Assuntos
Aterosclerose , Doença da Artéria Coronariana , Animais , Humanos , Camundongos , Aterosclerose/genética , Doença da Artéria Coronariana/genética , Camundongos Knockout , Camundongos Knockout para ApoE , Transdução de Sinais , Esteroide 17-alfa-Hidroxilase/genética
3.
Platelets ; 34(1): 2206915, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37154019

RESUMO

It is particularly important to establish more effective and safer antiplatelet treatment strategies according to age. The present subanalysis of the PATH-PCI trial was to determine the safety and efficacy of any dual-antiplatelet therapy (DAPT) strategy in different age groups. We randomized 2285 chronic coronary syndrome (CCS) patients undergoing percutaneous coronary intervention (PCI) into a standard group or a personalized group from December 2016 to February 2018. The personalized group received personalized antiplatelet therapy (PAT) based on a novel platelet function test (PFT). The standard group received standard antiplatelet therapy (SAT). Then, all patients were divided according to age (under the age of 65 years and aged 65 years or over) to investigate the association and interaction of age on clinical outcomes at 180 days. In the patients under the age of 65 years, the incidence of NACEs was decreased in the personalized group compared to the standard group (5.1% vs. 8.8%, HR: 0.603, 95% CI: 0.409-0.888, P = .010). The rates of MACCEs (3.3% vs. 7.7%, HR: 0.450, 95% CI: 0.285-0.712, P = .001), MACEs (2.2% vs. 5.4%, HR: 0.423, 95% CI: 0.243-0.738, P = .002) also decreased. We did not find a significant difference in bleeding between the groups. In the patients aged 65 years or over, no difference in the primary endpoint was found (4.9% vs. 4.2%, P = .702), and comparable rates of survival were observed with the two strategies (all Ps > 0.05). The present study shows that PAT according to PFT was comparable to SAT at the 180-day follow-up for both ischemic and bleeding endpoints in CCS patients aged 65 years or over who underwent PCI. In patients under the age of 65 years, PAT can reduce ischemic events but does not increase bleeding, and it is an effective and safe treatment strategy. It may be necessary for young CCS patients after PCI to undergo PAT early after PCI.


What is the context? The PATH-PCI trial reported that personalized antiplatelet therapy (PAT) based on a novel platelet function test (PFT) can greatly reduce the incidence of ischemic events.Antiplatelet strategies may have very different effects on clinical outcomes in patients in China who are undergoing PCI at different ages.What is new? PL-12 is a new point-of-care platelet function analyzer that is used to test the platelet maximum aggregation rate (MAR).We explored the efficacy and safety of different antiplatelet strategies in chronic coronary syndrome (CCS) patients in different age groups.What is the impact? PAT according to PFT was comparable to standard antiplatelet therapy (SAT) at the 180-day follow-up for both ischemic and bleeding endpoints in CCS patients aged 65 years or over who underwent PCI.In patients under the age of 65 years, PAT can reduce ischemic events but not increase bleeding.PAT may be an effective and safe treatment strategy in CCS patients under the age of 65 years who underwent PCI.Abbreviation: PCI: percutaneous coronary intervention; CCS: chronic coronary syndrome; DAPT: dual antiplatelet therapy; PAT: personalized antiplatelet therapy; SAT: standard antiplatelet therapy; PFT: platelet function test; NACEs: net adverse clinical events; MACCEs: major adverse cardiac and cerebrovascular events; MACEs: major adverse cardiovascular events.


Assuntos
Síndrome Coronariana Aguda , Intervenção Coronária Percutânea , Humanos , Síndrome Coronariana Aguda/terapia , Quimioterapia Combinada , Terapia Antiplaquetária Dupla , Hemorragia/tratamento farmacológico , Intervenção Coronária Percutânea/efeitos adversos , Inibidores da Agregação Plaquetária/farmacologia , Inibidores da Agregação Plaquetária/uso terapêutico , Resultado do Tratamento
4.
Molecules ; 27(19)2022 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-36234921

RESUMO

DNA-alkylating natural products play an important role in drug development due to their significant antitumor activities. They usually show high affinity with DNA through different mechanisms with the aid of their unique scaffold and highly active functional groups. Therefore, the biosynthesis of these natural products has been extensively studied, especially the construction of their pharmacophores. Meanwhile, their producing strains have evolved corresponding self-resistance strategies to protect themselves. To further promote the functional characterization of their biosynthetic pathways and lay the foundation for the discovery and rational design of DNA alkylating agents, we summarize herein the progress of research into DNA-alkylating antitumor natural products, including their biosynthesis, modes of action, and auto-resistance mechanisms.


Assuntos
Produtos Biológicos , Alquilantes/farmacologia , Produtos Biológicos/farmacologia , Vias Biossintéticas , DNA
5.
Catheter Cardiovasc Interv ; 95 Suppl 1: 572-578, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31912975

RESUMO

OBJECTIVES: To determine whether gamma-glutamyl transferase (GGT) to albumin ratio (GAR) independently predicts mortality and bleeding events in coronary artery disease (CAD) patients who undergo percutaneous coronary intervention (PCI). BACKGROUND: Serum GGT and albumin levels have been associated with CAD risk and mortality. However, more analysis is needed to determine their predictive relationship with adverse outcomes. METHODS: In total, 5,638 patients from a large retrospective cohort study were enrolled from January 2008 to December 2016 and divided into two groups (GAR <0.62, n = 2,712 and GAR ≥0.62, n = 2,926). The average follow-up time was 35.9 ± 22.6 months. Multivariate Cox regression analyses were performed to determine the risk of all-cause mortality and bleeding events associated with GAR. RESULTS: The low-GAR group had a significantly higher number of all-cause mortality (p = .016) and bleeding events (p = .010) than the high-GAR group. Multivariate Cox regression analyses showed that the risk of all-cause death and bleeding events decreased by 23.8% (hazard risk [HR] = 0.762 95% confidence interval [CI]: 0.601-0.966, p = .025) and 39.4% (HR = 00.616, 95% CI: 0.446-0.852, p = .003), respectively, in the high-GAR group. In patients with acute coronary syndrome, the risk of bleeding events decreased by 57.3% in the high-GAR group (HR = 0.427, 95% CI: 0.234-0.781, p = .006). In patients with stable coronary heart disease, the risk of all-cause death decreased 28.6% (HR = 0.714, 95% CI: 0.540-0.944, p = .018) in the high-GAR group. CONCLUSION: GAR was an independent and novel predictor of mortality and bleeding events in CAD patients who underwent PCI.


Assuntos
Doença da Artéria Coronariana/terapia , Hemorragia/etiologia , Intervenção Coronária Percutânea/efeitos adversos , Albumina Sérica Humana/análise , gama-Glutamiltransferase/sangue , Idoso , Biomarcadores/sangue , Doença da Artéria Coronariana/sangue , Doença da Artéria Coronariana/diagnóstico , Doença da Artéria Coronariana/mortalidade , Feminino , Hemorragia/mortalidade , Humanos , Masculino , Pessoa de Meia-Idade , Intervenção Coronária Percutânea/mortalidade , Valor Preditivo dos Testes , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento
6.
Lipids Health Dis ; 19(1): 43, 2020 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-32178685

RESUMO

BACKGROUND: Previous studies suggested that baseline white blood cell count and apolipoprotein A1 levels were associated with clinical outcomes in patients with coronary heart disease (CAD) who underwent percutaneous coronary intervention (PCI). However, the ratio of baseline white blood cell count-to-apolipoprotein A1 level (WAR) and CAD after PCI have not been investigated. The present study investigated the effects of baseline WAR on long-term outcomes after PCI in patients with CAD. METHODS: A total of 6050 patients with CAD who underwent PCI were included in the study. Of these, 372 patients were excluded because no baseline white blood cell counts or apolipoprotein A1 (ApoA1) data was available or because of malignancies or other diseases. Finally, 5678 patients were enrolled in the present study and were divided into 3 groups according to WAR value: lower group - WAR< 5.25 (n = 1889); median group - 5.25 ≤ WAR≤7.15 (n = 1892); and higher group - WAR≥7.15 (n = 1897). The primary endpoint was long-term mortality, including all-cause mortality (ACM) and cardiac mortality (CM), after PCI. The average follow-up time was 35.9 ± 22.6 months. RESULTS: A total of 293 patients developed ACM, including 85 (4.5%) patients in the lower group, 90 (4.8%) patients in the median group, and 118 (6.2%) patients in the higher group. The risk of ACM, cardiac mortality (CM), major adverse cardiovascular and cerebrovascular events (MACCEs), and major adverse cardiovascular events (MACEs) increased 62.6% (hazard risk [HR] =1.626, 95%CI: 1.214-2.179, P = 0.001), 45.5% (HR = 1.455, 95%CI: 1.051-2.014, P = 0.024), 21.2% (HR = 1.212, 95%CI: 1.011-1.454, P = 0.038), and 23.8% (HR = 1.238, 95%CI: 1.025-1.495, P = 0.027), respectively, as determined by multivariate Cox regression analyses comparing the patients in the higher group to patients in the lower group. Patients with a WAR≥4.635 had 92.3, 81.3, 58.1 and 58.2% increased risks of ACM, CM, MACCEs and MACEs, respectively, compared to the patients with WAR< 4.635. Every 1 unit increase in WAR was associated with 3.4, 3.2, 2.0 and 2.2% increased risks of ACM, CM, MACCEs and MACEs, respectively, at the 10-year follow-up. CONCLUSION: The present study indicated that baseline WAR is a novel and an independent predictor of adverse long-term outcomes in CAD patients who underwent PCI.


Assuntos
Apolipoproteína A-I/sangue , Doença da Artéria Coronariana/sangue , Doença da Artéria Coronariana/cirurgia , Contagem de Leucócitos , Idoso , Análise de Variância , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Intervenção Coronária Percutânea , Estudos Retrospectivos
7.
Mol Biol Evol ; 35(5): 1104-1119, 2018 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-29420738

RESUMO

Alternatively spliced transcript isoforms are thought to play a critical role for functional diversity. However, the mechanism generating the enormous diversity of spliced transcript isoforms remains unknown, and its biological significance remains unclear. We analyzed transcriptomes in saker falcons, chickens, and mice to show that alternative splicing occurs more frequently, yielding more isoforms, in highly expressed genes. We focused on hemoglobin in the falcon, the most abundantly expressed genes in blood, finding that alternative splicing produces 10-fold more isoforms than expected from the number of splice junctions in the genome. These isoforms were produced mainly by alternative use of de novo splice sites generated by transcription-associated mutation (TAM), not by the RNA editing mechanism normally invoked. We found that high expression of globin genes increases mutation frequencies during transcription, especially on nontranscribed DNA strands. After DNA replication, transcribed strands inherit these somatic mutations, creating de novo splice sites, and generating multiple distinct isoforms in the cell clone. Bisulfate sequencing revealed that DNA methylation may counteract this process by suppressing TAM, suggesting DNA methylation can spatially regulate RNA complexity. RNA profiling showed that falcons living on the high Qinghai-Tibetan Plateau possess greater global gene expression levels and higher diversity of mean to high abundance isoforms (reads per kilobases per million mapped reads ≥18) than their low-altitude counterparts, and we speculate that this may enhance their oxygen transport capacity under low-oxygen environments. Thus, TAM-induced RNA diversity may be physiologically significant, providing an alternative strategy in lifestyle evolution.


Assuntos
Adaptação Biológica , Processamento Alternativo , Evolução Molecular , Falconiformes/genética , Hemoglobinas/metabolismo , Animais , Galinhas , Metilação de DNA , Falconiformes/metabolismo , Variação Genética , Hemoglobinas/genética , Camundongos , Mutação , Oxigênio/metabolismo , Seleção Genética , Transcrição Gênica , Transcriptoma
8.
Lipids Health Dis ; 18(1): 140, 2019 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-31186012

RESUMO

BACKGROUND: The aim of this study was to assess the prognostic value of red blood cell distribution width (RDW) in patients with coronary artery disease undergoing percutaneous coronary intervention (PCI). METHODS: A retrospective cohort study (CORFCHD-PCI, [Identifier: ChiCTR-INR-16010153]) of 6050 patients who were hospitalized with a diagnosis of coronary artery disease (CAD) and treated with PCI from January 2008 to December 2016 were enrolled in the study. The primary outcome was long-term mortality after PCI. Clinical follow-up data of participating patients were obtained during an outpatient examination 35.9 ± 22.6 months after PCI. Demographic and clinical data and admission laboratory parameters were recorded, and patients were categorized into two groups according to RDW level (high group ≥13.1%; low group < 13.1%). RESULTS: Multivariate Cox regression analysis revealed RDW as an independent prognosis factor for cardiac death. The incidence of cardiac death increased 1.33 times in patients in the high RDW group (HR, 1.331; 95% CI, 1.009-1.755, P = 0.043). Kaplan-Meier survival analysis suggested that patients with high RDW tended to have an increased accumulated risk of cardiac death. However, we did not found significant differences in the incidence of long-term mortality (adjusted HR = 1.203[0.941-1.537], P = 0.140), MACCE (adjusted HR = 1.128[0.979-1.301], P = 0.096), MACE (adjusted HR = 1.155[0.994-1.341], P = 0.059), stroke, bleeding events or readmission between the two groups. CONCLUSION: The baseline level of RDW is an independent predictor for cardiac death in post-PCI CAD patients.


Assuntos
Doença da Artéria Coronariana/patologia , Eritrócitos/metabolismo , Idoso , Doença da Artéria Coronariana/metabolismo , Doença da Artéria Coronariana/terapia , Índices de Eritrócitos/fisiologia , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Intervenção Coronária Percutânea , Prognóstico , Estudos Retrospectivos , Fatores de Risco
9.
Proc Natl Acad Sci U S A ; 113(20): 5542-6, 2016 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-27140601

RESUMO

A three-dimensionally preserved 2-mm-long larva of the arthropod Leanchoilia illecebrosa from the 520-million-year-old early Cambrian Chengjiang biota of China represents the first evidence, to our knowledge, of such an early developmental stage in a short-great-appendage (SGA) arthropod. The larva possesses a pair of three-fingered great appendages, a hypostome, and four pairs of well-developed biramous appendages. More posteriorly, a series of rudimentary limb Anlagen revealed by X-ray microcomputed tomography shows a gradient of decreasing differentiation toward the rear. This, and postembryonic segment addition at the putative growth zone, are features of late-stage metanauplii of eucrustaceans. L. illecebrosa and other SGA arthropods, however, are considered representative of early chelicerates or part of the stem lineage of all euarthropods. The larva of an early Cambrian SGA arthropod with a small number of anterior segments and their respective appendages suggests that posthatching segment addition occurred in the ancestor of Euarthropoda.


Assuntos
Artrópodes/anatomia & histologia , Biota , Larva/anatomia & histologia , Animais , Artrópodes/ultraestrutura , China , Larva/ultraestrutura , Tomografia Computadorizada por Raios X
10.
Angew Chem Int Ed Engl ; 58(50): 18046-18054, 2019 12 09.
Artigo em Inglês | MEDLINE | ID: mdl-31553109

RESUMO

One biosynthetic gene cluster (BGC) usually governs the biosynthesis of a series of compounds exhibiting either the same or similar molecular scaffolds. Reported here is a multiplex activation strategy to awaken a cryptic BGC associated with tetracycline polyketides, resulting in the discovery of compounds having different core structures. By constitutively expressing a positive regulator gene in tandem mode, a single BGC directed the biosynthesis of eight aromatic polyketides with two types of frameworks, two pentacyclic isomers and six glycosylated tetracyclines. The proposed biosynthetic pathway, based on systematic gene inactivation and identification of intermediates, employs two sets of tailoring enzymes with a branching point from the same intermediate. These findings not only provide new insights into the role of tailoring enzymes in the diversification of polyketides, but also highlight a reliable strategy for genome mining of natural products.


Assuntos
Família Multigênica , Policetídeos/química , Policetídeos/metabolismo , Streptomyces/genética , Streptomyces/metabolismo , Perfilação da Expressão Gênica , Genes Bacterianos , Microrganismos Geneticamente Modificados , Estrutura Molecular , Mutação , Regiões Promotoras Genéticas
11.
Proc Biol Sci ; 285(1881)2018 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-29925613

RESUMO

Chancelloriids are an extinct group of spiny Cambrian animals of uncertain phylogenetic position. Despite their sponge-like body plan, their spines are unlike modern sponge spicules, but share several features with the sclerites of certain Cambrian bilaterians, notably halkieriids. However, a proposed homology of these 'coelosclerites' implies complex transitions in body plan evolution. A new species of chancelloriid, Allonnia nuda, from the lower Cambrian (Stage 3) Chengjiang Lagerstätte is distinguished by its large size and sparse spination, with modified apical sclerites surrounding an opening into the body cavity. The sclerite arrangement in A. nuda and certain other chancelloriids indicates that growth involved sclerite addition in a subapical region, thus maintaining distinct zones of body sclerites and apical sclerites. This pattern is not seen in halkieriids, but occurs in some modern calcarean sponges. With scleritome assembly consistent with a sponge affinity, and in the absence of cnidarian- or bilaterian-grade features, it is possible to interpret chancelloriids as sponges with an unusually robust outer epithelium, strict developmental control of body axis formation, distinctive spicule-like structures and, by implication, minute ostia too small to be resolved in fossils. In this light, chancelloriids may contribute to the emerging picture of high disparity among early sponges.


Assuntos
Evolução Biológica , Fósseis , Poríferos/crescimento & desenvolvimento , Animais , China , Fósseis/anatomia & histologia , Poríferos/anatomia & histologia
12.
Angew Chem Int Ed Engl ; 57(41): 13475-13479, 2018 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-30151879

RESUMO

Aromatic-fused γ-pyrones are structural features of many bioactive natural products and valid scaffolds for medicinal chemistry. However, the enzymology of their formation has not been completely established. Now it is demonstrated that TxnO9, a CalC-like protein belonging to a START family, functions as an unexpected anthraquinone-γ-pyrone synthase involved in the biosynthesis of antitumor antibiotic trioxacarcin A (TXN-A). Structural analysis by NMR identified a likely substrate/product-binding mode and putative key active sites of TxnO9, which allowed an enzymatic mechanism to be proposed. Moreover, a subset of uncharacterized homologous proteins bearing an unexamined Lys-Thr dyad exhibit the same function. Therefore, the functional assignment and mechanistic investigation of this γ-pyrone synthase elucidated an undescribed step in TXN-A biosynthesis, and the discovery of this new branch of polyketide heterocyclases expands the functions of the START superfamily.


Assuntos
Aminoglicosídeos/biossíntese , Antraquinonas/química , Antibióticos Antineoplásicos/biossíntese , Ligases/metabolismo , Policetídeos/metabolismo , Pironas/química , Aminoglicosídeos/química , Antibióticos Antineoplásicos/química , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Estrutura Molecular
13.
Zhongguo Zhong Yao Za Zhi ; 41(16): 3049-3054, 2016 Aug.
Artigo em Zh | MEDLINE | ID: mdl-28920347

RESUMO

The dried stems of Schisandra henryi var. henryi were extracted with 95% ethanol and the extracts were further subjected to partition, affording the ethyl acetate extracts(EtOAc Extrs.).The EtOAc Extrs.were separated and purified with silica gel and octadecyl-silylated silica gel column chromatography, preparative HPLC and preparative TLC. Thirteen known compounds were obtained and identified by spectral methods including MS and NMR, all of which were elucidated as t-cadinol(1), cadinane-4ß,5α,10ß-triol(2), cadinane-5α, 10α-diol-2-ene(3), oxyphyllenodiols A(4), 1ß, 4ß-dihydroxyeudesman-11-ene(5), cyperusol C(6), (7R)-opposit-4(15)-ene-1ß,7-diol(7), dysodensiol E(8), epi-guaidiol A(9), aromadendrane-4ß,10ß-diol(10), tricyclohumuladiol(11), caryolane-1,9ß-diol(12), and guaidiol A(13). Compounds 3, 5-10, and 13 were separated from the genus for the first time, while compounds 1-13 were separated from this species for the first time.


Assuntos
Schisandra/química , Sesquiterpenos/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Estrutura Molecular , Compostos Fitoquímicos/isolamento & purificação , Caules de Planta/química
14.
Curr Microbiol ; 71(4): 458-64, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26178900

RESUMO

Trioxacarcin A is a polyoxygenated, structurally complex antibiotic produced by Streptomyces spp., which possesses high anti-bacterial, anti-malaria, and anti-tumor activities. The trioxacarcin biosynthetic pathway involves type II polyketide synthases (PKSs) with L-isoleucine as a unique starter unit, as well as many complex post-PKS tailoring enzymes and resistance and regulatory proteins. In this work, two regulatory genes, txn9 coding for a Streptomyces antibiotic regulatory protein family regulator and txn11 for a two-component response regulator, were revealed to be absolutely required for trioxacarcin production by individually inactivating all the six annotated regulatory genes in the txn cluster. Complementation assay suggested that these two activators do not have a regulatory cascade relationship. Moreover, transcriptional analysis showed that they activate 15 of the 28 txn operons, indicating that a complicated regulatory network is involved in the trioxacarcin production. Information gained from this study may be useful for improving the production of the highly potent trioxacarcin A.


Assuntos
Aminoglicosídeos/biossíntese , Anti-Infecciosos/metabolismo , Antineoplásicos/metabolismo , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica , Streptomyces/genética , Transativadores/metabolismo , Deleção de Genes , Perfilação da Expressão Gênica , Redes Reguladoras de Genes , Teste de Complementação Genética , Família Multigênica , Streptomyces/metabolismo
15.
Guang Pu Xue Yu Guang Pu Fen Xi ; 35(9): 2393-6, 2015 Sep.
Artigo em Zh | MEDLINE | ID: mdl-26669136

RESUMO

Methyltin mercaptide is widely used as one of the best heat stabilizer in the polyvinylchloride (PVC) thermal processing due to its excellent stability, good transparency, high compatibility and weather resistance. The content of sulfur and tin significantly affects its quality and performance, so it is of great significance to develop an analytical method for the simultaneous determination of sulfur and tin. Inductively coupled plasma atomic emission spectrometry (ICP-OES) has been a powerful analytical tool for a myriad of complex samples owing to its advantages of the low detection limits, rapid and precise determinations over wide dynamic ranges, freedom from chemical inter-element interferences, the high sample throughput and above all, simultaneous multi-elements analysis. Microwave technique as a well-developed method for sample preparation can dramatically reduce the digestion time and the loss of volatile elements compared with the traditional open digestion. Hereby, a microwave-assisted acid digestion (MW-AAD) procedure followed by inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis was developed for the simultaneous determination of Sn and S in methyltin mercaptide. This method has the advantages of simplicity, rapidness, good accuracy, green and less use of samples. Parameters affecting the MW-AAD such as the digestion solution and digestion time were optimized by using a chemical analyzed reference sample (DX-181) to attain tin and sulfur quantitative recoveries. HNO3-HCl-HClO4 (v/v/v=9:3:1) and 10 min were the optimum digestion solution and digestion time, respectively. Under optimum conditions, the standard addition method and the standard calibration curve method were both been used to detect Sn and S in DX-181. There was no significant difference between two methods and the relative deviations to the chemical analysis values were both less than 2%. Additionally, the accuracy of the MW-AAD method was examined by analyzing three methyltin mercaptide samples (DX-181, DX-990, DX-960). The results were satisfactory with the relative deviations (<3%) and the recoveries of standard addition (99%~102%).

16.
Guang Pu Xue Yu Guang Pu Fen Xi ; 35(9): 2401-6, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26669138

RESUMO

A simple, sensitive and interference-free method was established for simultaneous determination of trace selenium and tellurium in ore samples by HG-AFS, by using nano-TiO2 immobilized on a silica gel packed microcolumn for online preconcentration. Selenium and tellurium were selectively adsorbed to the microcolumn in acidic condition and then completely eluted with 2% (m/v) NaOH solution. The experimental conditions for hydride generation, adsorption, elution and potential interference were investigated in detail. Under the optimum conditions, the detection limits of selenium and tellurium by the proposed method with 180 s sampling time were 4.0 and 3.6 ng · L(-1), with sensitivity enhancement of 20- and 13-fold compared to conventional hydride generation method, respectively. The relative standard deviation (RSD, n=5) of this method for 1 µg · L(-1) Se(IV) and Te(IV) were 0.7% and 2.3%, respectively. This method was applied to determination of selenium and tellurium in several ore samples.

17.
Zhongguo Zhong Xi Yi Jie He Za Zhi ; 34(1): 31-4, 2014 Jan.
Artigo em Zh | MEDLINE | ID: mdl-24520783

RESUMO

OBJECTIVE: To observe the change of intra-abdominal pressure (IAP) in severe acute pancreatitis (SAP) patients, and to study the effect of Qingyi Chengqi Decoction (QCD) on it. METHODS: Eighty-six SAP patients from Department of General Surgery and Department of Digestive Diseases, Qingyang People's Hospital, Gansu Province, who were in line with diagnosis standard of SAP, were assigned to the treatment group (44 cases) and the control group (42 cases) from March 2012 to May 2013. All patients received routine Western medicine. Those in the treatment group took QCD additionally. Main clinical symptoms and APACHE II were observed. The serum levels of amylase (AMY), C-reactive protein (CRP), and IAP were examined. The incidence of secondary infection rate (SIR), drainage rate (percutaneous catheter drainage and operation), mortality, and mean days in ward were also recorded. RESULTS: Main clinical symptoms were significantly improved in the treatment group. APACHE II score, serum levels of AMY, CRP, and IAP obviously decreased in the treatment group. The incidence of SIR, drainage rate, and the mortality were also significantly lower in the treatment group than in the control group. The mean days in ward were also markedly shortened (P < 0.01). CONCLUSION: QCD could relieve inflammatory response, lower IAP, SIR, and mortality, increase the curative rate and improve the prognosis of SAP.


Assuntos
Medicamentos de Ervas Chinesas/uso terapêutico , Pancreatite Necrosante Aguda/tratamento farmacológico , Fitoterapia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
18.
Fa Yi Xue Za Zhi ; 30(2): 112-3, 116, 2014 Apr.
Artigo em Zh | MEDLINE | ID: mdl-25073318

RESUMO

OBJECTIVE: To investigate the characteristics and influencing factors leading to sudden cardiac death (SCD) of incarcerated prisoners. METHODS: Seventy-five SCD cases of prisoners between 2000 and 2013 in Henan province were collected, and environment, psychological and physical factors were retrospectively analyzed. Combined with histopathological results, specific factors of SCD were also studied. RESULTS: In the 75 cases, 21 cases (28%) had definite chronic past medical histories, and 75 cases (100%) had cardiovascular disease confirmed by autopsy. CONCLUSION: Due to presence of the potential cardiac diseases, special incarcerated environment, psychological stress, and body-restraint might be the precipitating factors in SCD of those prisoners.


Assuntos
Morte Súbita Cardíaca , Prisioneiros , Autopsia , Doenças Cardiovasculares , Meio Ambiente , Humanos , Transtornos Mentais , Estudos Retrospectivos , Estresse Psicológico
19.
Ying Yong Sheng Tai Xue Bao ; 35(2): 447-456, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38523103

RESUMO

We conducted a field experiment in the dry farming area in south Ningxia from 2018 to 2021, to explore the influence of tillage methods combined with mulching on soil bulk density, aggregate content, soil water storage and potato yield under different precipitation years. There were four tillage methods (15 cm depth ploughing, and 30 cm, 40 cm and 50 cm depth subsoiling) and three mulching measures (mulching with oat straw, plastic film and no mulching), with the ploughing depth of 15 cm without mulching as control. The results showed the combination of tillage and mulching effectively reduced soil bulk density in 0-60 cm layer after three years of farming compared with that prior to the experiment. Under the same tillage mode, the best effect was achieved in mulching with oat straw under different precipitation years. To be specific, the best effect in 20 cm and 40 cm soil layers was achieved in mulching with oat straw for 30 cm depth subsoiling, in 60 cm soil layer for 15 cm ploughing in wet year, and for 40 cm depth subsoiling in 20 cm, 40 cm and 60 cm soil layers in normal and dry years. In 0-20 cm soil layer, the content of >0.25 mm soil aggregate was the highest for 40 cm depth subsoiling with oat straw mul-ching in all the three years. In 20-40 cm soil layer, the content was the highest for 15 cm depth ploughing with oat straw mulching in wet year, and for 40 cm depth subsoiling with oat straw mulching in normal and dry years. In 40-60 cm soil layer, content was the highest for 15 cm depth ploughing with plastic film mulching, 30 cm depth subsoiling with plastic film mulching, and 30 cm depth subsoiling with oat straw mulching in wet, normal and dry years, which was increased by 18.8%, 27.0%, and 35.8%, respectively, compared with the control. In the key growth stage (from squaring to tuber expansion) of potatoes, soil water storage in 0-100 cm layer was optimal for 30 cm depth subsoiling with oat straw mulching in wet year and for 40 cm depth subsoiling with oat straw mulching in normal and dry years, with an increase of 19.4%, 19.5%, and 23.7%, respectively. Potato yield was the highest for 30 cm depth subsoiling with oat straw mulching in wet year and for 40 cm depth subsoiling in normal and dry years, with an increase of 84.6%, 81.7%, and 106.3%, respectively. The correlation analysis showed that improved soil physical properties played a significant role in increasing potato yield, with the most significant role of soil bulk density and soil water storage at the squaring stage. Potato yield was high at a tillage depth of 34.67-36.03 cm. We concluded that the combination of tillage method and mulching could effectively improve soil physical pro-perties and increase soil water storage in the growth stage of potatoes, thereby significantly increa-sing potato yield. Potato yield in dry farming area could be enhanced through 30 cm depth subsoiling with oat straw mulching in wet years, and 40 cm depth subsoiling with oat straw mulching in normal and dry years.


Assuntos
Solo , Solanum tuberosum , Agricultura/métodos , Fazendas , Água , China , Zea mays
20.
Clin Cardiol ; 47(3): e24214, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38472152

RESUMO

BACKGROUND: This is a sub-analysis of the Personalized Antithrombotic Therapy for Coronary Heart Disease after PCI (PATH-PCI) trial in China to explore the relationship between smoking and outcomes following personalized antiplatelet therapy (PAT) in chronic coronary syndrome (CCS) patients undergoing percutaneous coronary intervention (PCI). METHODS: As a single-center, prospective, randomized controlled and open-label trial, the PATH-PCI trial randomized CCS patients undergoing PCI into standard group or personalized group guided by a novel platelet function test (PFT), from December 2016 to February 2018. All patients were divided into smokers and nonsmokers according to their smoking status. Subsequently, we underwent a 180-day follow-up evaluation. The primary endpoint was the net adverse clinical events (NACE). RESULTS: Regardless of smoking status, in the incidence of NACE, there was a reduction with PAT but that the reductions are not statistically significant. In the incidence of bleeding events, we found no statistically significant difference between two groups (smokers: 2.0% vs. 1.4%, HR = 1.455, 95% confidence interval [CI]: 0.595-3.559, p = .412; nonsmokers: 2.2% vs. 1.8%, HR = 1.228, 95% CI: 0.530-2.842, p = .632). In smokers, PAT reduced major adverse cardiac and cerebrovascular events (MACCE) by 48.7% (3.0% vs. 5.9%, HR = 0.513, 95% CI: 0.290-0.908, p = .022), compared with standard antiplatelet therapy (SAT). PAT also reduced the major adverse cardiovascular events (MACE) but there was no statistically difference in the reductions (p > .05). In nonsmokers, PAT reduced MACCE and MACE by 51.5% (3.3% vs. 6.7%, HR = 0.485, 95% CI: 0.277-0.849, p = .011) and 63.5% (1.8% vs. 4.9%, HR = 0.365, 95% CI: 0.178-0.752, p = .006), respectively. When testing p-values for interaction, we found there was no significant interaction of smoking status with treatment effects of PAT (pint-NACE = .184, pint-bleeding = .660). CONCLUSION: Regardless of smoking, PAT reduced the MACE and MACCE, with no significant difference in bleeding. This suggests that PAT was an recommendable regimen to CCS patients after PCI, taking into consideration both ischemic and bleeding risk.


Assuntos
Síndrome Coronariana Aguda , Intervenção Coronária Percutânea , Humanos , Síndrome Coronariana Aguda/terapia , Hemorragia/induzido quimicamente , Intervenção Coronária Percutânea/efeitos adversos , Inibidores da Agregação Plaquetária/efeitos adversos , Estudos Prospectivos , Fumar , Resultado do Tratamento
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