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1.
Nucleic Acids Res ; 52(D1): D483-D493, 2024 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-37941148

RESUMO

MESPEUS is a freely accessible database which uses carefully selected metal coordination groups found in metalloprotein structures taken from the Protein Data Bank. The database contains geometrical information of metal sites within proteins, including 40 metal types. In order to completely determine the metal coordination, the symmetry-related units of a given protein structure are taken into account and are generated using the appropriate space group symmetry operations. This permits a more complete description of the metal coordination geometry by including all coordinating atoms. The user-friendly web interface allows users to directly search for a metal site of interest using several useful options, including searching for metal elements, metal-donor distances, coordination number, donor residue group, and structural resolution. These searches can be carried out singly or in combination. The details of a metal site and the metal site(s) in the whole structure can be graphically displayed using the interactive web interface. MESPEUS is automatically updated monthly by synchronizing with the PDB database. An investigation for the Mg-ATP interaction is given to demonstrate how MESPEUS can be used to extract information about metal sites by selecting structure and coordination features. MESPEUS is available at http://mespeus.nchu.edu.tw/.


Assuntos
Metaloproteínas , Metaloproteínas/química , Metais/química , Bases de Dados de Proteínas , Interface Usuário-Computador , Internet
2.
Nucleic Acids Res ; 51(D1): D603-D610, 2023 01 06.
Artigo em Inglês | MEDLINE | ID: mdl-36399496

RESUMO

With an ever-increasing amount of (meta)genomic data being deposited in sequence databases, (meta)genome mining for natural product biosynthetic pathways occupies a critical role in the discovery of novel pharmaceutical drugs, crop protection agents and biomaterials. The genes that encode these pathways are often organised into biosynthetic gene clusters (BGCs). In 2015, we defined the Minimum Information about a Biosynthetic Gene cluster (MIBiG): a standardised data format that describes the minimally required information to uniquely characterise a BGC. We simultaneously constructed an accompanying online database of BGCs, which has since been widely used by the community as a reference dataset for BGCs and was expanded to 2021 entries in 2019 (MIBiG 2.0). Here, we describe MIBiG 3.0, a database update comprising large-scale validation and re-annotation of existing entries and 661 new entries. Particular attention was paid to the annotation of compound structures and biological activities, as well as protein domain selectivities. Together, these new features keep the database up-to-date, and will provide new opportunities for the scientific community to use its freely available data, e.g. for the training of new machine learning models to predict sequence-structure-function relationships for diverse natural products. MIBiG 3.0 is accessible online at https://mibig.secondarymetabolites.org/.


Assuntos
Genoma , Genômica , Família Multigênica , Vias Biossintéticas/genética
3.
Cell Mol Life Sci ; 80(8): 230, 2023 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-37498355

RESUMO

The aberrant activation of the nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome is known to contribute to the pathogenesis of various human inflammation-related diseases. However, to date, no small-molecule NLRP3 inhibitor has been used in clinical settings. In this study, we have identified SB-222200 as a novel direct NLRP3 inhibitor through the use of drug affinity responsive target stability assay, cellular thermal shift assay, and surface plasmon resonance analysis. SB-222200 effectively inhibits the activation of the NLRP3 inflammasome in macrophages, while having no impact on the activation of NLRC4 or AIM2 inflammasome. Furthermore, SB-222200 directly binds to the NLRP3 protein, inhibiting NLRP3 inflammasome assembly by blocking the NEK7 - NLRP3 interaction and NLRP3 oligomerization. Importantly, treatment with SB-222200 demonstrates alleviation of NLRP3-dependent inflammatory diseases in mouse models, such as monosodium urate crystal-induced peritonitis and dextran sulfate sodium-induced acute intestinal inflammation. Therefore, SB-222200 holds promise as a lead compound for the development of NLRP3 inhibitors to combat NLRP3-driven disease and serves as a versatile tool for pharmacologically investigating NLRP3 biology.


Assuntos
Proteína 3 que Contém Domínio de Pirina da Família NLR , Peritonite , Camundongos , Animais , Humanos , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Inflamassomos/metabolismo , Peritonite/induzido quimicamente , Peritonite/tratamento farmacológico , Peritonite/metabolismo , Macrófagos/metabolismo , Inflamação/metabolismo , Camundongos Endogâmicos C57BL , Interleucina-1beta/metabolismo
4.
Neurobiol Dis ; 181: 106096, 2023 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-37001611

RESUMO

Striatal medium spiny neurons (MSNs) and striatal dopamine (DA) innervation are profoundly important for brain function such as motor control and cognition. A widely accepted theory posits that striatal DA loss causes (or leads to) MSN dendritic atrophy. However, examination of the literature indicates that the data from Parkinson's disease (PD) patients and animal PD models were contradictory among studies and hard to interpret. Here we have re-examined the potential effects of DA activity on MSN morphology or lack thereof. We found that in 15-day, 4- and 12-month old Pitx3 null mutant mice that have severe DA denervation in the dorsal striatum while having substantial residual DA innervation in the ventral striatum, MSN dendrites and spine numbers were similar in dorsal and ventral striatum, and also similar to those in normal mice. In 15-day, 4- and 12-month old tyrosine hydroxylase knockout mice that cannot synthesize L-dopa and thus have no endogenous DA in the entire brain, MSN dendrites and spine numbers were also indistinguishable from age-matched wild-type (WT) mice. Furthermore, in adult WT mice, unilateral 6-OHDA lesion at 12 months of age caused an almost complete striatal DA denervation in the lesioned side, but MSN dendrites and spine numbers were similar in the lesioned and control sides. Taken together, our data indicate that in mice, the development and maintenance of MSN dendrites and spines are DA-independent such that DA depletion does not trigger MSN dendritic atrophy; our data also suggest that the reported MSN dendritic atrophy in PD may be a component of neurodegeneration in PD rather than a consequence of DA denervation.


Assuntos
Dopamina , Doença de Parkinson , Camundongos , Animais , Dopamina/fisiologia , Neurônios/patologia , Espinhas Dendríticas/patologia , Neurônios Espinhosos Médios , Levodopa/farmacologia , Doença de Parkinson/patologia , Corpo Estriado/patologia
5.
Mol Psychiatry ; 27(11): 4754-4769, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35948662

RESUMO

Vascular cognitive impairment and dementia (VCID) is the second most common form of dementia after Alzheimer's disease (AD). Currently, the mechanistic insights into the evolution and progression of VCID remain elusive. White matter change represents an invariant feature. Compelling clinical neuroimaging and pathological evidence suggest a link between white matter changes and neurodegeneration. Our prior study detected hypoperfused lesions in mice with partial deficiency of endothelial nitric oxide (eNOS) at very young age, precisely matching to those hypoperfused areas identified in preclinical AD patients. White matter tracts are particularly susceptible to the vascular damage induced by chronic hypoperfusion. Using immunohistochemistry, we detected severe demyelination in the middle-aged eNOS-deficient mice. The demyelinated areas were confined to cortical and subcortical areas including the corpus callosum and hippocampus. The intensity of demyelination correlated with behavioral deficits of gait and associative recognition memory performances. By Evans blue angiography, we detected blood-brain barrier (BBB) leakage as another early pathological change affecting frontal and parietal cortex in eNOS-deficient mice. Sodium nitrate fortified drinking water provided to young and middle-aged eNOS-deficient mice completely prevented non-perfusion, BBB leakage, and white matter pathology, indicating that impaired endothelium-derived NO signaling may have caused these pathological events. Furthermore, genome-wide transcriptomic analysis revealed altered gene clusters most related to mitochondrial respiratory pathways selectively in the white matter of young eNOS-deficient mice. Using eNOS-deficient mice, we identified BBB breakdown and hypoperfusion as the two earliest pathological events, resulting from insufficient vascular NO signaling. We speculate that the compromised BBB and mild chronic hypoperfusion trigger vascular damage, along with oxidative stress and astrogliosis, accounting for the white matter pathological changes in the eNOS-deficient mouse model. We conclude that eNOS-deficient mice represent an ideal spontaneous evolving model for studying the earliest events leading to white matter changes, which will be instrumental to future therapeutic testing of drug candidates and for targeting novel/specific vascular mechanisms contributing to VCID and AD.


Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Demência Vascular , Substância Branca , Animais , Camundongos , Substância Branca/patologia , Óxido Nítrico/metabolismo , Circulação Cerebrovascular , Demência Vascular/patologia , Demência Vascular/psicologia , Modelos Animais de Doenças , Disfunção Cognitiva/metabolismo , Doença de Alzheimer/metabolismo
6.
J Therm Biol ; 116: 103649, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37478582

RESUMO

Abnormal temperature has important effects on the occurrence of ischemic stroke (IS). However, relatively less efforts have been taken to systematically unravel the association between various abnormal temperature and IS hospital admission. Focusing on three temperature indicators (i.e., mean temperature, maximum temperature, and minimum temperature), this study attempts to analyse how their abnormal values affect IS hospital admission. The dataset covers the period between September 17, 2012 and August 28, 2018, and includes a total of 1464 cases who were admitted to the hospital for the first onset of IS and lived in the main urban area of Guangzhou. The study adopts the time-stratified case-crossover analysis. Abnormal values of temperature were measured using the 2.5th and 97.5th quantile values of each temperature indicator, with the former refers to a low value whereas the latter a high one. The effects of abnormal temperature on IS hospital admission were assessed through calculating the relative risks induced by the low and high values (the median values of each temperature indicators were taken as the references). The results show that the risk window periods for IS hospital admission associated with the low values of the temperature indicators are the lags of 3-7 days and 18-19 days. The risks of high temperature values on IS admission, however, are insignificant with either one-day lag or cumulative lag. As to different population groups, females show higher risks of IS hospital admission at low temperature values than males; and elderly people, compared with young people, are more vulnerable to low temperature values. To cities with similar climate of Guangzhou, particular attention should be paid to the impact of low temperature values, especially the low value of minimum temperature, on IS admission, and to females and elderly people who are more sensitive to abnormal temperatures.


Assuntos
Poluição do Ar , AVC Isquêmico , Masculino , Feminino , Humanos , Idoso , Adolescente , Temperatura , China/epidemiologia , Hospitais
7.
Am J Pathol ; 191(11): 1932-1945, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-33711310

RESUMO

Age-related cerebral small-vessel disease (CSVD) is a major cause of stroke and dementia. Despite a widespread acceptance of small-vessel arteriopathy, lacunar infarction, diffuse white matter injury, and cognitive impairment as four cardinal features of CSVD, a unifying pathologic mechanism of CSVD remains elusive. Herein, we introduce partial endothelial nitric oxide synthase (eNOS)-deficient mice as a model of age-dependent, spontaneous CSVD. These mice developed cerebral hypoperfusion and blood-brain barrier leakage at a young age, which progressively worsened with advanced age. Their brains exhibited elevated oxidative stress, astrogliosis, cerebral amyloid angiopathy, microbleeds, microinfarction, and white matter pathology. Partial eNOS-deficient mice developed gait disturbances at middle age, and hippocampus-dependent memory deficits at older ages. These mice also showed enhanced expression of bone morphogenetic protein 4 (BMP4) in brain pericytes before myelin loss and white matter pathology. Because BMP4 signaling not only promotes astrogliogenesis but also blocks oligodendrocyte differentiation, we posit that paracrine actions of BMP4, localized within the neurovascular unit, promote white matter disorganization and neurodegeneration. These observations point to BMP4 signaling pathway in the aging brain vasculature as a potential therapeutic target. Finally, because studies in partial eNOS-deficient mice corroborated recent clinical evidence that blood-brain barrier disruption is a primary cause of white matter pathology, the mechanism of impaired nitric oxide signaling-mediated CSVD warrants further investigation.


Assuntos
Proteína Morfogenética Óssea 4/metabolismo , Doenças de Pequenos Vasos Cerebrais/metabolismo , Doenças de Pequenos Vasos Cerebrais/fisiopatologia , Modelos Animais de Doenças , Óxido Nítrico Sintase Tipo III/deficiência , Animais , Doenças de Pequenos Vasos Cerebrais/patologia , Camundongos
8.
Biochem Genet ; 60(6): 2052-2068, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35235083

RESUMO

Severe Acute Respiratory Syndrome Coronavirus Type 2 (SARS-CoV-2) is an enveloped single-stranded RNA virus that can lead to respiratory symptoms and damage many organs such as heart, kidney, intestine, brain and liver. It has not been clearly documented whether myocardial injury is caused by direct infection of cardiomyocytes, lung injury, or other unknown mechanisms. The gene expression profile of GSE150392 was obtained from the Gene Expression Omnibus (GEO) database. The processing of high-throughput sequencing data and the screening of differentially expressed genes (DEGs) were implemented by R software. The R software was employed to analyze the Gene Ontology (GO) analysis and the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. The protein-protein interaction (PPI) network of the DEGs was constructed by the STRING website. The Cytoscape software was applied for the visualization of PPI network and the identification of hub genes. The statistical analysis was performed by the GraphPad Prism software to verify the hub genes. A total of 516 up-regulated genes and 191 down-regulated genes were screened out. The top 1 enrichment items of GO in biological process (BP), Cellular Component (CC), and Molecular Function (MF) were type I interferon signaling pathway, sarcomere, and receptor ligand activity, respectively. The top 10 enrichment pathways, including TNF signaling pathway, were identified by KEGG enrichment analysis. A PPI network was established, consisting of 613 nodes and 3,993 edges. The 12 hub genes were confirmed as statistically significant, which was verified by GSE151879 dataset. In conclusion, the hub genes of human iPSC-cardiomyocytes infected with SARS-CoV-2 were identified through bioinformatics analysis, which may be used as biomarkers for further research.


Assuntos
COVID-19 , Células-Tronco Pluripotentes Induzidas , Humanos , SARS-CoV-2 , Perfilação da Expressão Gênica , Miócitos Cardíacos , COVID-19/genética , Biologia Computacional , Transdução de Sinais/genética
9.
BMC Musculoskelet Disord ; 22(1): 1049, 2021 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-34930199

RESUMO

BACKGROUND: The aim of this study was to analyze the effect of unilateral K-rod dynamic internal fixation on paraspinal muscles for lumbar degenerative diseases. METHODS: This study retrospectively collected 52 patients who underwent lumbar surgery with the K-rod group or PLIF. The operation time, intraoperative blood loss, postoperative drainage volume, postoperative exercise time were compared in the two groups. The visual analog scale (VAS) score and the oswestry dysfunction index (ODI) were employed to evaluate the clinical outcomes. The functional cross-sectional area (FCSA) of the paraspinal muscles and paraspinal muscles fat infiltration were measured to assess on the paraspinal muscles. RESULTS: As compared with the PLIF group, the operation time, the postoperative time in the field, and the average postoperative hospital stay in the K-rod internal fixation group were significantly shortened. At the last follow-up, both the groups showed significant improvement in the VAS score and ODI. The FCSA atrophy of the upper and lower adjacent segments (UAS and LAS) of the K-rod internal group was significantly less than that of the PLIF group. The extent of increase in the fatty infiltration of the paraspinal muscles in the K-rod group was significantly lesser than that in the PLIF group. The postoperative low back pain of the two groups of patients was significantly positively correlated with the FCSA atrophy. CONCLUSIONS: As compared to PLIF, the posterior lumbar unilateral K-rod dynamic internal fixation showed significantly lesser paraspinal muscle atrophy and fatty infiltration, which were significantly positively correlated with postoperative low back pain.


Assuntos
Região Lombossacral , Músculos Paraespinais , Fixação Interna de Fraturas , Humanos , Região Lombossacral/diagnóstico por imagem , Região Lombossacral/cirurgia , Músculos Paraespinais/diagnóstico por imagem , Período Pós-Operatório , Estudos Retrospectivos
10.
Stat Med ; 39(27): 4051-4068, 2020 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-32875597

RESUMO

The sufficient component cause (SCC) model and counterfactual model are two common methods for causal inference, each with their own advantages: the SCC model allows the mechanistic interaction to be detailed, whereas the counterfactual model features a systemic framework for quantifying causal effects. Hence, integrating the SCC and counterfactual models may facilitate the conceptualization of causation. Based on the marginal SCC (mSCC) model, we propose a novel counterfactual mSCC framework that includes the steps of definition, identification, and estimation. We further propose a six-way effect decomposition for assessing mediation and the mechanistic interaction. The results demonstrate that when all variables are binary, the six-way decomposition is an extension of four-way decomposition and that without agonism, the six-way decomposition is reduced to four-way decomposition. To illustrate the utility of the proposed decomposition, we apply it to a Taiwanese cohort to examine the mechanism of hepatitis C virus (HCV)-induced hepatocellular carcinoma (HCC) with liver inflammation measured by alanine aminotransferase (ALT) as a mediator. Among the HCV-induced HCC cases, 62.27% are not explained by either mediation or interaction in relation to ALT; 9.32% are purely mediated by ALT; 16.53% are caused by the synergistic effect of HCV and ALT; and 9.31% are due to the mediated synergistic effect of HCV and ALT. In summary, we introduce an SCC model framework based on counterfactual theory and detail the required identification assumptions and estimation procedures; we also propose a six-way effect decomposition to unify mediation and mechanistic interaction analyses.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Causalidade , Interpretação Estatística de Dados , Humanos , Neoplasias Hepáticas/etiologia , Modelos Estatísticos
11.
BMC Infect Dis ; 20(1): 650, 2020 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-32887568

RESUMO

BACKGROUND: Cryptococcus is a conditional pathogenic fungus causing cryptococcosis, which is one of the most serious fungal diseases faced by humans. Lateral flow immunochromatographic assay (LFA) is successfully applied to the rapid detection of cryptococcal antigens. METHODS: Studies were retrieved systematically from the Embase, PubMed, Web of Science, and Cochrane Library before July 2019. The quality of the studies was assessed by Review Manager 5.0 based on the Quality Assessment of Diagnostic Accuracy Study guidelines. The extracted data from the included studies were analyzed by Meta-DiSc 1.4. Stata 12.0 software was used to detect the publication bias. RESULTS: A total of 15 articles with 31 fourfold tables were adopted by inclusion and exclusion criteria. The merged sensitivity and specificity in serum were 0.98 and 0.98, respectively, and those in the cerebrospinal fluid were 0.99 and 0.99, respectively. CONCLUSIONS: Compared to the urine and other samples, LFA in serum and cerebrospinal fluid is favorable evidence for the diagnosis of cryptococcosis with high specificity and sensitivity.


Assuntos
Criptococose/diagnóstico , Imunoensaio/métodos , Antígenos de Fungos/sangue , Antígenos de Fungos/líquido cefalorraquidiano , Antígenos de Fungos/urina , Líquido Cefalorraquidiano/microbiologia , Testes Diagnósticos de Rotina/métodos , Humanos , Sensibilidade e Especificidade
12.
Int J Med Sci ; 17(3): 338-346, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32132869

RESUMO

Treatment of advanced hepatocellular carcinoma (HCC) has exhibited a poor overall survival rate of only six to ten months, and the urgency of the development of more effective novel agents is ever present. In this line of research, we aimed to investigate the effects and inhibitive mechanisms of aqueous Ocimum gratissimum leaf extract (OGE), the extract of Ocimum gratissimum, which is commonly used as a therapeutic herb for its numerous pharmacological properties, on malignant HCC cells. Our results showed that OGE decreased the cell viability of HCC SK-Hep1 and HA22T cells in a dose-dependent manner (from 400 to 800 µg/mL), while there is little effect on Chang liver cells. Moreover, cell-cycle analysis shows increased Sub-G1 cell count in SK-Hep1 and HA22T cells which is not observed in Chang liver cells. These findings raise suspicion that the OGE-induced cell death may be mediated through proteins that regulate cell cycle and apoptosis in SK-Hep1 and HA22T cells, and further experimentation revealed that OGE treatment resulted in a dose-dependent decrease in caspase 3 and PARP expressions and in CDK4and p-ERK1/2expressions. Moreover, animal tests also exhibited decreased HCC tumor growth by OGE treatment. We therefore suggest that the inhibition of cell viability and tumor growth induced by OGE may be correlated to the alteration of apoptosis-related proteins.


Assuntos
Carcinoma Hepatocelular/tratamento farmacológico , Neoplasias Hepáticas/tratamento farmacológico , Ocimum/química , Extratos Vegetais/química , Extratos Vegetais/uso terapêutico , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Western Blotting , Carcinoma Hepatocelular/metabolismo , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Feminino , Citometria de Fluxo , Humanos , Neoplasias Hepáticas/metabolismo , Camundongos , Camundongos Nus , Consumo de Oxigênio
13.
Proc Natl Acad Sci U S A ; 114(39): 10408-10413, 2017 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-28874588

RESUMO

The Diels-Alder reaction is one of the most common methods to chemically synthesize a six-membered carbocycle. While it has long been speculated that the cyclohexene moiety found in many secondary metabolites is also introduced via similar chemistry, the enzyme SpnF involved in the biosynthesis of the insecticide spinosyn A in Saccharopolyspora spinosa is the first enzyme for which catalysis of an intramolecular [Formula: see text]-cycloaddition has been experimentally verified as its only known function. Since its discovery, a number of additional standalone [Formula: see text]-cyclases have been reported as potential Diels-Alderases; however, whether their catalytic cycles involve a concerted or stepwise cyclization mechanism has not been addressed experimentally. Here, we report direct experimental interrogation of the reaction coordinate for the [Formula: see text]-carbocyclase SpnF via the measurement of [Formula: see text]-secondary deuterium kinetic isotope effects (KIEs) at all sites of [Formula: see text] rehybridization for both the nonenzymatic and enzyme-catalyzed cyclization of the SpnF substrate. The measured KIEs for the nonenzymatic reaction are consistent with previous computational results implicating an intermediary state between formation of the first and second carbon-carbon bonds. The KIEs measured for the enzymatic reaction suggest a similar mechanism of cyclization within the enzyme active site; however, there is evidence that conformational restriction of the substrate may play a role in catalysis.


Assuntos
Reação de Cicloadição , Macrolídeos/metabolismo , Metiltransferases/metabolismo , Domínio Catalítico/fisiologia , Saccharopolyspora/enzimologia , Saccharopolyspora/metabolismo
14.
J Am Chem Soc ; 141(36): 14152-14159, 2019 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-31150226

RESUMO

Peptidyl nucleoside antibiotics (PNAs) are a diverse class of natural products with promising biomedical activities. These compounds have tripartite structures composed of a core saccharide, a nucleobase, and one or more amino acids. In particular, amipurimycin and the miharamycins are novel 2-aminopurinyl PNAs with complex nine-carbon core saccharides and include the unusual amino acids (-)-cispentacin and N5-hydroxyarginine, respectively. Despite their interesting structures and properties, these PNAs have heretofore eluded biochemical scrutiny. Herein is reported the discovery and initial characterization of the miharamycin gene cluster in Streptomyces miharaensis (mhr) and the amipurimycin gene cluster (amc) in Streptomyces novoguineensis and Streptomyces sp. SN-C1. The gene clusters were identified using a comparative genomics approach, and heterologous expression of the amc cluster as well as gene interruption experiments in the mhr cluster support their role in the biosynthesis of amipurimycin and the miharamycins, respectively. The mhr and amc biosynthetic gene clusters characterized encode enzymes typical of polyketide biosynthesis instead of enzymes commonly associated with PNA biosynthesis, which, along with labeled precursor feeding studies, implies that the core saccharides found in the miharamycins and amipurimycin are partially assembled as polyketides rather than derived solely from carbohydrates. Furthermore, in vitro analysis of Mhr20 and Amc18 established their roles as ATP-grasp ligases involved in the attachment of the pendant amino acids found in these PNAs, and Mhr24 was found to be an unusual hydroxylase involved in the biosynthesis of N5-hydroxyarginine. Finally, analysis of the amc cluster and feeding studies also led to the proposal of a biosynthetic pathway for (-)-cispentacin.


Assuntos
Antibacterianos/biossíntese , N-Glicosil Hidrolases/biossíntese , Nucleosídeos/biossíntese , Purinas/biossíntese , Antibacterianos/química , Vias Biossintéticas , Conformação Molecular , Família Multigênica , N-Glicosil Hidrolases/química , N-Glicosil Hidrolases/genética , Nucleosídeos/química , Nucleosídeos/genética , Purinas/química , Streptomyces/genética
15.
Anal Chem ; 91(5): 3740-3746, 2019 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-30699297

RESUMO

A noninvasive breath test has the potential to improve survival from esophagogastric cancer by facilitating earlier detection. This study aimed to investigate the production of target volatile fatty acids (VFAs) in esophagogastric cancer through analysis of the ex vivo headspace above underivatized tissues and in vivo analysis within defined anatomical compartments, including analysis of mixed breath, isolated bronchial breath, and gastric-endoluminal air. VFAs were measured by PTR-ToF-MS and GC-MS. Levels of VFAs (acetic, butyric, pentanoic, and hexanoic acids) and acetone were elevated in ex vivo experiments in the headspace above esophagogastric cancer compared with the levels in samples from control subjects with morphologically normal and benign conditions of the upper gastrointestinal tract. In 25 patients with esophagogastric cancer and 20 control subjects, receiver-operating-characteristic analysis for the cancer-specific VFAs butyric acid ( P < 0.001) and pentatonic acid ( P = 0.005) within in vivo gastric-endoluminal air gave an area under the curve of 0.80 (95% confidence interval of 0.65 to 0.93, P = 0.01). Compared with mixed- and bronchial-breath samples, all examined VFAs were found in highest concentrations within esophagogastric-endoluminal air. In addition, VFAs were higher in all samples derived from cancer patients compared with in the controls. Equivalence of VFA levels within the mixed and bronchial breath of cancer patients suggests that their origin within breath is principally derived from the lungs and, by inference, from the systemic circulation as opposed to direct passage from the upper gastrointestinal tract. These findings highlight the potential to utilize VFAs for endoluminal-gas biopsies and noninvasive mixed-exhaled-breath testing for esophagogastric-cancer detection.


Assuntos
Testes Respiratórios/métodos , Neoplasias Esofágicas/diagnóstico , Ácidos Graxos Voláteis/análise , Espectrometria de Massas/métodos , Neoplasias Gástricas/diagnóstico , Estudos de Casos e Controles , Cromatografia Gasosa-Espectrometria de Massas/métodos , Humanos , Curva ROC
16.
Beilstein J Org Chem ; 15: 2889-2906, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31839835

RESUMO

Terpenoids are the largest and structurally most diverse class of natural products. They possess potent and specific biological activity in multiple assays and against diseases, including cancer and malaria as notable examples. Although the number of characterized terpenoid molecules is huge, our knowledge of how they are biosynthesized is limited, particularly when compared to the well-studied thiotemplate assembly lines. Bacteria have only recently been recognized as having the genetic potential to biosynthesize a large number of complex terpenoids, but our current ability to associate genetic potential with molecular structure is severely restricted. The canonical terpene biosynthetic pathway uses a single enzyme to form a cyclized hydrocarbon backbone followed by modifications with a suite of tailoring enzymes that can generate dozens of different products from a single backbone. This functional promiscuity of terpene biosynthetic pathways renders terpene biosynthesis susceptible to rational pathway engineering using the latest developments in the field of synthetic biology. These engineered pathways will not only facilitate the rational creation of both known and novel terpenoids, their development will deepen our understanding of a significant branch of biosynthesis. The biosynthetic insights gained will likely empower a greater degree of engineering proficiency for non-natural terpene biosynthetic pathways and pave the way towards the biotechnological production of high value terpenoids.

17.
Biochemistry ; 57(22): 3130-3133, 2018 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-29473739

RESUMO

DesII is a radical SAM lyase that catalyzes a deamination reaction during the biosynthesis of desosamine in Streptomyces venezuelae. Competing mechanistic hypotheses for this radical-mediated reaction are differentiated according to whether a 1,2-migration takes place and the timing of proton abstraction following generation of a substrate α-hydroxyalkyl radical intermediate. In this study, the deuterated C4 epimer of the natural substrate, TDP-4-amino-4-deoxy-d-[3-2H]fucose, was prepared and shown to be a substrate for DesII undergoing deamination alone with a specific activity that is only marginally reduced (∼3-fold) with respect to that of deamination of the natural substrate. Furthermore, pH titration of the deamination reaction implicates the presence of a hydron acceptor that facilitates catalysis but does not appear to be necessary. On the basis of these as well as previously reported results, a mechanism involving direct elimination of ammonium with concerted proton transfer to the nucleofuge from the adjacent α-hydroxyalkyl radical is proposed.


Assuntos
Fucose/química , Açúcares de Nucleosídeo Difosfato/química , Amino Açúcares , Compostos de Amônio/metabolismo , Catálise , Desaminação , Fucose/metabolismo , Açúcares de Nucleosídeo Difosfato/metabolismo , Oxirredutases/metabolismo , S-Adenosilmetionina/metabolismo , Streptomyces/enzimologia , Nucleotídeos de Timina/química
18.
Int J Colorectal Dis ; 33(10): 1367-1371, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30008115

RESUMO

PURPOSE: The rate of postoperative morbidity and mortality is reportedly high in patients aged ≥ 75 years with colorectal cancer (CRC). In such patients, a comparison of the short-term outcome between open method and laparoscopy has not been clearly defined in Taiwan. We aimed to compare postoperative morbidity and mortality parameters after open method and laparoscopy in CRC patients aged ≥ 75 years. METHODS: We retrospectively analyzed patients who underwent surgery for CRC from February 2009 to September 2015 at the Linkou Chang Gung Memorial Hospital in Taiwan and analyzed their clinicopathological factors. Postoperative morbidity and mortality were analyzed for evaluating if laparoscopic surgery offers more favorable outcomes than open surgery in the elderly. RESULTS: A total of 1133 patients were enrolled and analyzed in this study; they were divided into two groups (open method vs. laparoscopy = 797 vs. 336). The anastomotic leakage rate was significantly higher in the laparoscopy group than in the open method group (3.3 vs. 0.9%, p = 0.003). Overall postoperative morbidity and mortality rates showed no significant difference between these two groups. Postoperative hospital stay was significantly shorter in the laparoscopy group than in the open method group (10.4 ± 8.7 vs. 13.8 ± 13.5 days, p < 0.001). CONCLUSIONS: Our results suggest that laparoscopy in patients aged ≥ 75 years with CRC had higher anastomosis leakage rate compared with open surgery but is acceptable and offers the benefit of a shorter hospital stay over open surgery.


Assuntos
Fístula Anastomótica , Colectomia , Neoplasias Colorretais , Complicações Pós-Operatórias , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Fístula Anastomótica/diagnóstico , Fístula Anastomótica/etiologia , Colectomia/efeitos adversos , Colectomia/métodos , Neoplasias Colorretais/epidemiologia , Neoplasias Colorretais/patologia , Neoplasias Colorretais/cirurgia , Feminino , Humanos , Laparoscopia/efeitos adversos , Laparoscopia/métodos , Tempo de Internação/estatística & dados numéricos , Masculino , Seleção de Pacientes , Complicações Pós-Operatórias/classificação , Complicações Pós-Operatórias/mortalidade , Estudos Retrospectivos , Risco Ajustado/métodos , Taiwan/epidemiologia , Resultado do Tratamento
19.
Int J Mol Sci ; 19(12)2018 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-30551684

RESUMO

Leptin, a hormone secreted by peripheral adipose tissues, regulates the appetite in animals. Recently, evidence has shown that leptin also plays roles in behavioral response in addition to controlling appetite. In this study, we examined the potential function of leptin on non-appetite behaviors in zebrafish model. By using genome editing tool of Transcription activator-like effector nuclease (TALEN), we successfully knocked out leptin a (lepa) gene by deleting 4 bp within coding region to create a premature-translation stop. Morphological and appetite analysis showed the lepa KO fish display a phenotype with obese, good appetite and elevation of Agouti-related peptide (AgRP) and Ghrelin hormones, consistent with the canonical function of leptin in controlling food intake. By multiple behavior endpoint analyses, including novel tank, mirror biting, predator avoidance, social interaction, shoaling, circadian rhythm, and color preference assay, we found the lepa KO fish display an anxiogenic phenotype showing hyperactivity with rapid swimming, less freezing time, less fear to predator, loose shoaling area forming, and circadian rhythm and color preference dysregulations. Using biochemical assays, melatonin, norepinephrine, acetylcholine and serotonin levels in the brain were found to be significantly reduced in lepa KO fish, while the levels of dopamine, glycine and cortisol in the brain were significantly elevated. In addition, the brain ROS level was elevated, and the anti-oxidative enzyme catalase level was reduced. Taken together, by performing loss-of-function multiple behavior endpoint testing and biochemical analysis, we provide strong evidence for a critical role of lepa gene in modulating anxiety, aggression, fear, and circadian rhythm behaviors in zebrafish for the first time.


Assuntos
Leptina/genética , Obesidade/genética , Deleção de Sequência , Estresse Psicológico/genética , Proteínas de Peixe-Zebra/genética , Peixe-Zebra/genética , Agressão , Animais , Ansiedade/genética , Ansiedade/metabolismo , Apetite , Biomarcadores/metabolismo , Química Encefálica , Ritmo Circadiano , Modelos Animais de Doenças , Medo , Feminino , Edição de Genes , Masculino , Obesidade/metabolismo , Estresse Psicológico/metabolismo
20.
J Am Chem Soc ; 139(46): 16450-16453, 2017 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-29111702

RESUMO

Herbicidins are adenosine-based nucleoside antibiotics with an unusual tricyclic undecose core decorated with a (5-hydroxy)tiglyl moiety. Feeding studies are herein reported demonstrating that the tricyclic core is derived from d-glucose and d-ribose, whereas the tiglyl moiety is derived from an intermediate of l-isoleucine catabolism. Identification of the gene cluster for herbicidin A biosynthesis in Streptomyces sp. L-9-10 as well as its verification by heterologous expression in a nonproducing host are described, and the results of in vitro characterization of a carboxyl methyltransferase encoded in the cluster, Her8, are presented. Based on these observations, a biosynthetic pathway is proposed for herbicidins.


Assuntos
Antibacterianos/biossíntese , Nucleosídeos de Purina/biossíntese , Antibacterianos/química , Antibacterianos/metabolismo , Conformação Molecular , Família Multigênica , Nucleosídeos de Purina/química , Nucleosídeos de Purina/genética , Streptomyces/química , Streptomyces/metabolismo
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