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1.
Heliyon ; 10(3): e24525, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38356565

RESUMO

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is primarily utilized in traumatic noncompressible torso hemorrhage as a temporary approach to buying time until a definite intervention could be obtained. REBOA is mostly reported in inhospital or prehospital settings. Its interhospital transfer use remains controversial. In this report, we present a case with pelvic fracture and hemorrhagic shock who underwent REBOA placement and was transferred from a local hospital to a trauma center successfully for further surgical intervention.

3.
Cell Rep ; 42(1): 111955, 2023 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-36640333

RESUMO

Delivery of cancer therapeutics to non-specific sites decreases treatment efficacy while increasing toxicity. In ovarian cancer, overexpression of the cell surface marker HER2, which several therapeutics target, relates to poor prognosis. We recently reported the assembly of biocompatible bacterial spore-like particles, termed "SSHELs." Here, we modify SSHELs with an affibody directed against HER2 and load them with the chemotherapeutic agent doxorubicin. Drug-loaded SSHELs reduce tumor growth and increase survival with lower toxicity in a mouse tumor xenograft model compared with free drug and with liposomal doxorubicin by preferentially accumulating in the tumor mass. Target cells actively internalize and then traffic bound SSHELs to acidic compartments, whereupon the cargo is released to the cytosol in a pH-dependent manner. We propose that SSHELs represent a versatile strategy for targeted drug delivery, especially in cancer settings.


Assuntos
Neoplasias , Esporos Bacterianos , Camundongos , Humanos , Animais , Esporos Bacterianos/metabolismo , Sistemas de Liberação de Medicamentos , Membrana Celular/metabolismo , Neoplasias/metabolismo , Proteínas de Bactérias/metabolismo , Bacillus subtilis/metabolismo
4.
J Hazard Mater ; 430: 128431, 2022 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-35150991

RESUMO

Microplastics (MPs) pollution has become a serious environmental issue worldwide, but its potential effects on health remain unknown. The administration of polystyrene MPs (PS-MPs) to mice for eight weeks impaired learning and memory behavior. PS-MPs were detected in the brain especially in the hippocampus of these mice. Concurrently, the hippocampus had decreased levels of immediate-early genes, aberrantly enhanced synaptic glutamate AMPA receptors, and elevated neuroinflammation, all of which are critical for synaptic plasticity and memory. Interestingly, ablation of the vagus nerve, a modulator of the gut-brain axis, improved the memory function of PS-MPs mice. These results indicate that exposure to PS-MPs in mice alters the expression of neuronal activity-dependent genes and synaptic proteins, and increases neuroinflammation in the hippocampus, subsequently causing behavioral changes through the vagus nerve-dependent pathway. Our findings shed light on the adverse impacts of PS-MPs on the brain and hippocampal learning and memory.


Assuntos
Microplásticos , Poliestirenos , Animais , Ácido Glutâmico , Hipocampo , Camundongos , Plásticos , Poliestirenos/toxicidade
5.
Artigo em Inglês | MEDLINE | ID: mdl-32522108

RESUMO

A liquid chromatography-high resolution mass spectrometry (LC-HRMS) method was developed and validated for the determination of residual peptide antibiotics (bacitracin A, colistin A and B, enramycin A and B, virginiamycin M1 and S1) in bovine milk. LC-HRMS accurate mass data provided the necessary selectivity and sensitivity to quantitate and identify these important antibiotics in milk at residue levels without extensive sample preparation. Milk samples were extracted using 0.3% formic acid in acetonitrile with 0.06% trifluoroacetic acid added to improve peptide recoveries. Sample clean-up was minimal with an aliquot of the extract evaporated and reconstituted in a formic acid/water-acetonitrile mixture and then filtered. LC separation was performed with 0.3% formic acid in the gradient to improve the peak shape and reproducibility of the peptide analytes. A Quadruple-Orbitrap HRMS instrument with full-scan MS1 data collection followed by all-ion-fragmentation was used to obtain the exact mass of the precursor and confirmatory product ions. One advantage of LC-HRMS is that a combination of multiple precursor ions, including different charge states or adducts, can be used for quantification. The method was validated at four concentration levels ranging from 12.5 to 200 ng/g in three types of bovine milk. For bacitracin A, colistins and enramycins, the average recoveries compared to solvent standards ranged between 70% and 120%. Average recoveries for virginiamycin residues in milk extracts were unacceptably high (up to 138%) using solvent standards, but recoveries using matrix-matched calibration were determined to be 90-115%. Matrix effects were found to be less than 25% for the other analytes when internal standard correction was used for the colistins. Intra-day relative standard deviations were generally below 15%. The method detection limits for the peptide antibiotic residues in milk (0.5 to 5.5 ng/g) were well below regulatory levels of concern.


Assuntos
Antibacterianos/análise , Resíduos de Drogas/análise , Leite/química , Peptídeos/análise , Animais , Bovinos , Cromatografia Líquida , Espectrometria de Massas
6.
Rapid Commun Mass Spectrom ; 34(7): e8642, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-31702084

RESUMO

RATIONALE: A current trend in monitoring chemical contaminants in animal products is to use high-resolution mass spectrometry (HRMS). In this study, several HRMS data acquistion modes using Orbitrap MS for simultaneous full-scan MS in combination with MS2 analysis were evaulated for their effectiveness in detecting and identifying both targeted and non-targeted veterinary drug residues in aquacultured eel samples. METHODS: Sample preparation consisted of an acidic acetonitrile extraction with solid-phase extraction cleanup for analysis using LC/HRMS. Different data acquisition methods, including full-scan MS with non-targeted all ion fragmentation (AIF), multiplexed or variable data-independent analysis (mDIA or vDIA), targeted data-dependent MS2 (DDMS2), and parallel reaction monitoring (PRM) acquisition, were explored. The methods were evaluated with fortified eel tissue and imported eel samples to determine how many analytes could be detected and identified. RESULTS: For non-targeted data acquisition, the number of analytes detected using DIA methods matched the results obtained by AIF, but the resulting product ion scans were more diagnostic because characteristic ions were predominant in the DIA MS2 spectra. In targeted analysis for a limited list of 68 compounds, full-scan MS followed by PRM was advantageous compared with DDMS2 because high-quality MS2 spectra were generated for almost all the analytes at target testing levels. CONCLUSIONS: For residue screening, AIF has fast MS1 scan speed with adequate detection of product ions but may lead to false positive findings. DIA methods are better suited to monitor for both targeted and non-targeted compounds because they generate more characteristic MS2 spectra for retrospective library searching. For follow-up targeted analysis, PRM is prefered over DDMS2 when searching for a limited set of compounds.


Assuntos
Enguias/metabolismo , Drogas Veterinárias/análise , Animais , Cromatografia Líquida , Resíduos de Drogas/análise , Resíduos de Drogas/metabolismo , Limite de Detecção , Software , Espectrometria de Massas em Tandem/métodos , Drogas Veterinárias/metabolismo
7.
Artigo em Inglês | MEDLINE | ID: mdl-31361192

RESUMO

A liquid chromatography high resolution mass spectrometry (LC-HRMS) screening method was developed previously to analyze for veterinary drug residues commonly found in different types of aquaculture products. This method has been further evaluated for its feasibility to detect several other classes of compounds that might also be a concern as possible contaminants in farmed tilapia, salmon, eel and shrimp. Some chemicals could contaminate water sources used in aquaculture production through agricultural run-off. These compounds include several widely used triazine herbicides, organophosphate and carbamate pesticides, as well as various discarded human pharmaceuticals. Other possible contaminants investigated were selected disinfectants, some newer antibiotics, growth promoters, and various parasiticides. The sample preparation consisted of an acidic acetonitrile extraction followed by solid-phase extraction clean-up. Data were collected with a quadrupole-Orbitrap MS using both non-targeted and targeted acquisition. This rapid clean-up procedure and HRMS detection method described previously for veterinary drug residues also worked well for many other types of compounds. Most analytes had screening limit levels between 0.5-10 ng/g in the matrices examined using exact mass identification criteria. The strategy described in this paper for testing the performance of additional analytes will help expand the applicability of the HRMS procedure as aquaculture samples can now be analyzed for a wider range of contaminants.


Assuntos
Aquicultura , Resíduos de Drogas/análise , Produtos Pesqueiros/análise , Peixes , Análise de Alimentos , Contaminação de Alimentos/análise , Praguicidas/análise , Drogas Veterinárias/análise , Animais , Cromatografia Líquida , Humanos , Espectrometria de Massas
8.
World J Emerg Surg ; 13: 38, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30181768

RESUMO

Background: The triage system used during an actual mass burn casualty (MBC) incident is a major focus of concern. This study introduces a MBC triage system that was used by a burn center during an actual MBC incident following a powder explosion in New Taipei City, Taiwan. Methods: This study retrospectively analyzed data from patients who were sent to the study hospital during a MBC incident. The patient list was retrieved from a national online management system. A MBC triage system was developed at the study hospital using the following modifiers: consciousness, breathing, and burn size. Medical records were retrieved from electronic records for analysis. Patient outcomes consisted of emergency department (ED) disposition and intervention. Results: The patient population was predominantly female (56.3%), with an average age of 24.9 years. Mean burn sizes relative to the TBSA of triage level I, II, and III patients were 57.9%, 40.5%, and 8.7%, respectively. ICU length of stay differed markedly according to triage level (mean days for levels I vs II vs III: 57.9 vs 39.9 vs 2.5 days; p < 0.001). Triage system levels I and II indicate ICU admission with a sensitivity of 93.9% (95%CI 80.4-98.3%) and a specificity of 86.7% (62.1-96.3%).Overall, 3 (6.3%) patients were under-triaged. Two (4.2%) patients were over-triaged. Sixteen (48.5%) and 21 (63.6%) patients of triage levels I and II received endotracheal intubation and central venous catheterization, respectively. Sorting of the study population with simple triage and rapid treatment (START) showed great sensitivity (100.0%) but poor specificity (53.3%). The Taiwan Triage and Acuity Scale (TTAS) presented 87.9% sensitivity and 93.9% specificity. Conclusions: The current MBC triage algorithm served as a good indicator of ED disposition but might have raised excessive immediate attention and had the potential to exhaust the available resources. These findings add to our knowledge of the MBC triage system and should help future researchers in adjusting the triage criteria to fit actual disasters.


Assuntos
Substâncias Explosivas/efeitos adversos , Incidentes com Feridos em Massa , Triagem/métodos , Triagem/normas , Adulto , Queimaduras/terapia , Planejamento em Desastres/métodos , Serviços Médicos de Emergência/métodos , Serviços Médicos de Emergência/tendências , Feminino , Hospitais , Humanos , Masculino , Estudos Retrospectivos , Taiwan
9.
FEMS Microbiol Lett ; 365(18)2018 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-30084923

RESUMO

Spores of Bacillus subtilis are encased in a protein coat composed of ∼80 different proteins. Recently, we reconstituted the basement layer of the coat, composed of two structural proteins (SpoVM and SpoIVA) around spore-sized silica beads encased in a lipid bilayer, to create synthetic spore-like particles termed 'SSHELs'. We demonstrated that SSHELs could display thousands of copies of proteins and small molecules of interest covalently linked to SpoIVA. In this study, we investigated the efficacy of SSHELs in delivering vaccines. We show that intramuscular vaccination of mice with undecorated one micron-diameter SSHELs elicited an antibody response against SpoIVA. We further demonstrate that SSHELs covalently modified with a catalytically inactivated staphylococcal alpha toxin variant (HlaH35L), without an adjuvant, resulted in improved protection against Staphylococcus aureus infection in a bacteremia model as compared to vaccination with the antigen alone. Although vaccination with either HlaH35L or HlaH35L conjugated to SSHELs similarly elicited the production of neutralizing antibodies to Hla, we found that a subset of memory T cells was differentially activated when the antigen was delivered on SSHELs. We propose that the particulate nature of SSHELs elicits a more robust immune response to the vaccine that results in superior protection against subsequent S. aureus infection.


Assuntos
Toxinas Bacterianas/imunologia , Portadores de Fármacos/administração & dosagem , Proteínas Hemolisinas/imunologia , Infecções Estafilocócicas/prevenção & controle , Vacinas Antiestafilocócicas/imunologia , Animais , Anticorpos Antibacterianos/sangue , Anticorpos Neutralizantes/sangue , Bacteriemia/prevenção & controle , Proteínas de Bactérias/genética , Toxinas Bacterianas/genética , Modelos Animais de Doenças , Proteínas Hemolisinas/genética , Injeções Intramusculares , Camundongos , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/imunologia , Vacinas Antiestafilocócicas/administração & dosagem , Vacinas Antiestafilocócicas/genética , Subpopulações de Linfócitos T/imunologia , Resultado do Tratamento , Vacinas de Subunidades Antigênicas/administração & dosagem , Vacinas de Subunidades Antigênicas/genética , Vacinas de Subunidades Antigênicas/imunologia , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologia
10.
Anal Bioanal Chem ; 410(22): 5529-5544, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29445835

RESUMO

The ability to detect chemical contaminants, including veterinary drug residues in animal products such as fish, is an important example of food safety analysis. In this paper, a liquid chromatography high-resolution mass spectrometry (LC-HRMS) screening method using a quadrupole-Orbitrap instrument was applied to the analysis of veterinary drug residues in incurred tissues from aquacultured channel catfish, rainbow trout, and Atlantic salmon and imported aquacultured products including European eel, yellow croaker, and tilapia. Compared to traditional MS methods, the use of HRMS with nontargeted data acquisition and exact mass measurement capability greatly increased the scope of compounds that could be monitored simultaneously. The fish samples were prepared for analysis using a simple efficient procedure that consisted of an acidic acetonitrile extraction followed by solid phase extraction cleanup. Two different HRMS acquisition programs were used to analyze the fish extracts. This method detected and identified veterinary drugs including quinolones, fluoroquinolones, avermectins, dyes, and aminopenicillins at residue levels in fish that had been dosed with those compounds. A metabolite of amoxicillin, amoxicillin diketone, was also found at high levels in catfish, trout, and salmon. The method was also used to characterize drug residues in imported fish. In addition to confirming findings of fluoroquinolone and sulfonamide residues that were found by traditional targeted MS methods, several new compounds including 2-amino mebendazole in eel and ofloxacin in croaker were detected and identified. Graphical Abstract Aquacultured samples are analyzed with a high-resolution mass spectrometry screening method to detect and identify unusual veterinary drug residues including ofloxacin in an imported fish.


Assuntos
Resíduos de Drogas/análise , Contaminação de Alimentos/análise , Alimentos Marinhos/análise , Espectrometria de Massas em Tandem/métodos , Drogas Veterinárias/análise , Animais , Aquicultura , Cromatografia Líquida de Alta Pressão/métodos , Peixes , Análise de Perigos e Pontos Críticos de Controle/métodos
11.
BMC Pulm Med ; 17(1): 82, 2017 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-28472944

RESUMO

BACKGROUND: Mycobacterium tuberculosis (TB) is one of the world's most devastating public health threats. Our goal is to evaluate whether the use of non-steroidal anti-inflammatory drugs (NSAIDs) affect the risk of new incident active TB disease. METHODS: We conducted a nested case-control analysis by using a 1 million longitudinally followed cohort, from Taiwan's national health insurance research database. Effects of NSAIDs on active TB were estimated by conditional logistic regression and adjusted using a TB-specific disease risk score (DRS). NSAIDs exposures were defined as having a prescription record of NSAIDs ≧ 7 days that ended between 31 and 90 days prior to the index date. RESULTS: A total of 123,419 users of traditional NSAIDs, 16,392 users of cyclooxygenase-2 selective inhibitor (Coxibs), and 4706 incident cases of active TB were identified. Compared with nonusers, use of traditional NSAIDs was associated with an increased risk of TB in the unadjusted analysis ([RR], 1.39; 95% [CI], 1.24 - 1.57 and DRS adjusted analysis ([ARR], 1.30; 95% [CI], 1.15- 1.47). However, use of Coxibs was not associated with a significant increase in the risk of TB after DRS adjustment ([ARR], 1.23; 95% [CI], 0.89 - 1.70). CONCLUSIONS: In this large population-based study, we found that subjects using traditional NSAIDs were associated with increased risk for active TB. We did not find evidence for a causative mechanism between traditional NSAIDs and TB, and more research is required to verify whether the association between traditional NSAIDs and TB is causal, or simply reflects an increased use of anti-inflammatory drugs in the early phases of TB onset.


Assuntos
Anti-Inflamatórios não Esteroides/efeitos adversos , Tuberculose/epidemiologia , Adulto , Idoso , Estudos de Casos e Controles , Inibidores de Ciclo-Oxigenase 2/uso terapêutico , Bases de Dados Factuais , Feminino , Humanos , Modelos Logísticos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Programas Nacionais de Saúde , Fatores de Risco , Taiwan/epidemiologia , Fatores de Tempo
12.
Clin Toxicol (Phila) ; 55(7): 670-673, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28463019

RESUMO

CONTEXT: Accidental ingestion of foxglove (Digitalis purpurea) can cause significant cardiac toxicity. We report a patient who ingested foxglove mistaking it for comfrey and developed refractory ventricular arrhythmias. The patient died despite treatment with digoxin-specific antibody fragments (DSFab) and veno-arterial extracorporeal membrane oxygenation (VA-ECMO). CASE DETAILS: A 55-year-old woman presented to the emergency department with nausea, vomiting and generalized weakness eight hours after drinking "comfrey" tea. She had bradycardia (54 beats/min) and hyperkalemia (7.6 mEq/L). Electrocardiogram revealed a first-degree atrioventricular conduction block with premature atrial contractions, followed by polymorphic ventricular tachycardia three hours after arrival. A serum digoxin level was 151.2 ng/mL. The patient developed ventricular fibrillation while waiting for Digibind infusion. Resuscitation was performed and an emergent VA-ECMO was set up. A total of eight vials of Digibind were given over the next 16 hours. She temporarily regained consciousness, but remained hemodynamically unstable and subsequently developed lower limb ischemia and multiple organ failure, and she expired on hospital day seven. A botanist confirmed that the plant was foxglove. CONCLUSIONS: The diagnosis of cardiac glycoside plant poisoning can be difficult in the absence of an accurate exposure history. In facilities where DSFab is unavailable or insufficient, early VA-ECMO might be considered in severely cardiotoxic patients unresponsive to conventional therapy.


Assuntos
Acidentes , Glicosídeos Cardíacos/intoxicação , Confrei , Digitalis/intoxicação , Cardiopatias/induzido quimicamente , Intoxicação por Plantas/etiologia , Cardiotoxicidade , Eletrocardiografia , Oxigenação por Membrana Extracorpórea , Evolução Fatal , Feminino , Cardiopatias/diagnóstico , Cardiopatias/terapia , Humanos , Fragmentos Fab das Imunoglobulinas/uso terapêutico , Pessoa de Meia-Idade , Intoxicação por Plantas/diagnóstico , Intoxicação por Plantas/terapia , Valor Preditivo dos Testes , Ressuscitação , Fatores de Tempo , Resultado do Tratamento
13.
Crit Care Med ; 44(1): e45-7, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26468896

RESUMO

OBJECTIVE: To describe the experience of emergency extracorporeal membrane oxygenation in treating life-threatening glyphosate-surfactant intoxication. DESIGN: Case report. SETTING: Emergency department and ICU. PATIENT: A patient with cardiopulmonary failure after glyphosate-surfactant intoxication. INTERVENTION: Extracorporeal membrane oxygenation. CASE REPORT: A 47-year-old man presented with mildly decreased consciousness in our emergency department after ingesting approximately 100 mL of glyphosate-surfactant 1.5 hours previously. Respiratory failure, persistent ventricular tachycardia, profound shock refractory to inotropic agents, and metabolic acidosis developed in the patient within 2 hours. Extracorporeal membrane oxygenation was applied within 4 hours of cardiopulmonary failure. The patient's condition improved considerably. He was transferred to the general ward on the eighth day with stable hemodynamic status and complete neurological recovery. CONCLUSIONS: On the basis of our research, this was the first case in which extracorporeal membrane oxygenation was used to treat severe glyphosate-surfactant intoxication. We recommend early initiation of extracorporeal membrane oxygenation therapy to mitigate cardiopulmonary compromise in patients with glyphosate-surfactant intoxication.


Assuntos
Oxigenação por Membrana Extracorpórea , Glicina/análogos & derivados , Herbicidas/intoxicação , Tratamento de Emergência , Glicina/intoxicação , Humanos , Masculino , Pessoa de Meia-Idade , Intoxicação/terapia , Indução de Remissão , Índice de Gravidade de Doença , Glifosato
14.
Nat Commun ; 6: 6777, 2015 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-25854653

RESUMO

Dormant bacterial spores are encased in a thick protein shell, the 'coat', which contains ∼70 different proteins. The coat protects the spore from environmental insults, and is among the most durable static structures in biology. Owing to extensive cross-linking among coat proteins, this structure has been recalcitrant to detailed biochemical analysis, so molecular details of how it assembles are largely unknown. Here, we reconstitute the basement layer of the coat atop spherical membranes supported by silica beads to create artificial spore-like particles. We report that these synthetic spore husk-encased lipid bilayers (SSHELs) assemble and polymerize into a static structure, mimicking in vivo basement layer assembly during sporulation in Bacillus subtilis. In addition, we demonstrate that SSHELs may be easily covalently modified with small molecules and proteins. We propose that SSHELs may be versatile display platforms for drugs and vaccines in clinical settings, or for enzymes that neutralize pollutants for environmental remediation.


Assuntos
Bacillus subtilis , Proteínas de Bactérias/metabolismo , Parede Celular/metabolismo , Bicamadas Lipídicas/metabolismo , Nanotecnologia , Dióxido de Silício , Esporos Bacterianos/metabolismo
15.
Am J Emerg Med ; 33(6): 865.e5-6, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25619873

RESUMO

A 46-year-old male patient with tetralogy of Fallot presented to the emergency department with progressive dyspnea for 3 days. The dyspnea was refractory to treatment for tet spells. Pulmonary embolism (PE) was subsequently diagnosed by computed tomography, and the patient was successfully treated with heparinization. Chronic hypoxemia-induced secondary polycythemia and the consequent increase in blood hyperviscosity predisposed this patient to PE. This case reminds us of the similarity in clinical presentation between PE and tet spells.


Assuntos
Embolia Pulmonar/etiologia , Tetralogia de Fallot/complicações , Anticoagulantes/uso terapêutico , Diagnóstico Diferencial , Humanos , Masculino , Pessoa de Meia-Idade , Embolia Pulmonar/diagnóstico por imagem , Embolia Pulmonar/tratamento farmacológico , Tomografia Computadorizada por Raios X
16.
Chembiochem ; 14(8): 968-78, 2013 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-23625817

RESUMO

A simple and efficient method is described for the introduction of noncanonical amino acids at multiple, defined sites within recombinant polypeptide sequences. Escherichia coli MRA30, a bacterial host strain with attenuated activity of release factor 1 (RF1), was assessed for its ability to support incorporation of a diverse range of noncanonical amino acids in response to multiple encoded amber (TAG) codons within genes derived from superfolder GFP and an elastin-mimetic protein polymer. Suppression efficiency and protein yield depended on the identity of the orthogonal aminoacyl-tRNA synthetase/tRNA(CUA) pair and the noncanonical amino acid. Elastin-mimetic protein polymers were prepared in which noncanonical amino acid derivatives were incorporated at up to 22 specific sites within the polypeptide sequence with high substitution efficiency. The identities and positions of the variant residues were confirmed by mass spectrometric analysis of the full-length polypeptides and proteolytic cleavage fragments from thermolysin digestion. The data suggest that this multisite suppression approach permits the preparation of protein-based materials in which novel chemical functionalities can be introduced at precisely defined positions within the polypeptide sequence.


Assuntos
Aminoácidos/genética , Escherichia coli/genética , Mutagênese Insercional/métodos , Peptídeos/genética , Sequência de Aminoácidos , Aminoácidos/química , Elastina/química , Elastina/genética , Escherichia coli/metabolismo , Dados de Sequência Molecular , Peptídeos/química , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Sequências Repetitivas de Ácido Nucleico
17.
Front Microbiol ; 3: 60, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22371709

RESUMO

The replication and transcription activator (RTA) of Kaposi's sarcoma-associated herpesvirus (KSHV), K-RTA, is a lytic switch protein that moderates the reactivation process of KSHV latency. By mass spectrometric analysis of affinity purified K-RTA, we showed that Thr-513 or Thr-514 was the primary in vivo phosphorylation site. Thr-513 and Thr-514 are proximal to the nuclear localization signal ((527)KKRK(530)) and were previously hypothesized to be target sites of Ser/Thr kinase hKFC. However, substitutions of Thr with Ala at 513 and 514 had no effect on K-RTA subcellular localization or transactivation activity. By contrast, replacement of Ser with Ala at Ser-634 and Ser-636 located in a Ser/Pro-rich region of K-RTA, designated as S634A/S636A, produced a polypeptide with ∼10 kDa shorter in molecular weight and reduced transactivation in a luciferase reporter assay relative to the wild type. In contrast to prediction, the decrease in molecular weight was not due to lack of phosphorylation because the overall Ser and Thr phosphorylation state in K-RTA and S634A/S636A were similar, excluding that Ser-634 or Ser-636 motif served as docking sites for consecutive phosphorylation. Interestingly, S634A/S636A lost ∼30% immuno-reactivity to MPM2, an antibody specific to pSer/pThr-Pro motif, indicating that (634)SPSP(637) motif was in vivo phosphorylated. By in vitro kinase assay, we showed that K-RTA is a substrate of CDK9, a Pro-directed Ser/Thr kinase central to transcriptional regulation. Importantly, the capability of K-RTA in associating with endogenous CDK9 was reduced in S634A/S636A, which suggested that Ser-634 and Ser-636 may be involved in CDK9 recruitment. In agreement, S634A/S636A mutant exhibited ∼25% reduction in KSHV lytic cycle reactivation relative to that by the wild type K-RTA. Taken together, our data propose that Ser-634 and Ser-636 of K-RTA are phosphorylated by host transcriptional kinase CDK9 and such a process contributes to a full transcriptional potency of K-RTA.

18.
J Biomed Sci ; 19: 12, 2012 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-22300411

RESUMO

BACKGROUND: The replication and transcription activator (RTA) of Kaposi's sarcoma-associated herpesvirus (KSHV) is a molecular switch that initiates a productive replication of latent KSHV genomes. KSHV RTA (K-RTA) is composed of 691 amino acids with high Ser and Thr content (17.7%), but to what extent these Ser and Thr are modified in vivo has not been explored. METHODS: By using tandem mass spectrometric analysis of affinity-purified FLAG tagged K-RTA, we sought to identify Ser and Thr residues that are post-translationally modified in K-RTA. RESULTS: We found that K-RTA is an O-GlcNAcylated protein and Thr-366/Thr-367 is the primary motif with O-GlcNAcylation in vivo. The biological significance of O-GlcNAc modified Thr-366 and Thr-367 was assessed by site-specific amino acid substitution. Replacement of Thr with Ala at amino acid 366 or 367 caused a modest enhancement of K-RTA transactivation activity in a luciferase reporter assay and a cell model for KSHV reactivation. By using co-immunoprecipitation coupled with western blot analysis, we showed that the capacity of K-RTA in associating with endogenous PARP1 was significantly reduced in the Thr-366/Thr-367 O-GlcNAc mutants. PARP1 is a documented negative regulator of K-RTA that can be ascribed by the attachment of large negatively charged polymer onto K-RTA via PARP1's poly (ADP-ribose) polymerase activity. In agreement, shRNA-mediated depletion of O-GlcNAc transferase (OGT) in KSHV infected cells augmented viral reactivation and virus production that was accompanied by diminished K-RTA and PARP1 complexes. CONCLUSIONS: KSHV latent-lytic switch K-RTA is modified by cellular O-GlcNAcylation, which imposes a negative effect on K-RTA transactivation activity. This inhibitory effect involves OGT and PARP1, two nutritional sensors recently emerging as chromatin modifiers. Thus, we speculate that the activity of K-RTA on its target genes is continuously checked and modulated by OGT and PARP1 in response to cellular metabolic state.


Assuntos
Regulação Viral da Expressão Gênica , Herpesvirus Humano 8/genética , Proteínas Imediatamente Precoces/genética , N-Acetilglucosaminiltransferases/genética , Transativadores/genética , Acilação , Alanina/química , Substituição de Aminoácidos , Western Blotting , Cromatografia Gasosa-Espectrometria de Massas , Células HEK293 , Herpesvirus Humano 8/metabolismo , Humanos , Proteínas Imediatamente Precoces/metabolismo , Imunoprecipitação , N-Acetilglucosaminiltransferases/metabolismo , Oligopeptídeos , Peptídeos/metabolismo , Poli(ADP-Ribose) Polimerase-1 , Poli(ADP-Ribose) Polimerases/metabolismo , RNA Interferente Pequeno/metabolismo , Espectrometria de Massas em Tandem , Treonina/química , Transativadores/metabolismo
19.
Anal Bioanal Chem ; 402(9): 2765-76, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22287049

RESUMO

Glycoproteins secreted or expressed on the cell surface at specific pathophysiological stages are well-recognized disease biomarkers and therapeutic targets. While mapping of specific glycan structures can be performed at the level of released glycans, site-specific glycosylation and identification of specific protein carriers can only be determined by analysis of glycopeptides. A key enabling step in mass spectrometry (MS)-based glycoproteomics is the ability to selectively or non-selectively enrich for the glycopeptides from a total pool of a digested proteome for MS analysis since the highly heterogeneous glycopeptides are usually present at low abundance and ionize poorly compared with non-glycosylated peptides. Among the most common approaches for non-destructive and non-glycan-selective glycopeptide enrichment are strategies based on various forms of hydrophilic interaction liquid chromatography (HILIC). We present here a variation of this method using amine-derivatized Fe(3)O(4) nanoparticles, in concert with in situ peptide N-glycosidase F digestion for direct matrix-assisted laser desorption/ionization­mass spectrometry analysis of N-glycosylation sites and the released glycans. Conditions were also optimized for efficient elution of the enriched glycopeptides from the nanoparticles for on-line nanoflow liquid chromatography­MS/MS analysis. Successful applications to single glycoproteins as well as total proteomic mixtures derived from biological fluids established the unrivaled practical versatility of this method, with enrichment efficiency comparable to other HILIC-based methods.


Assuntos
Glicopeptídeos/química , Nanopartículas/química , Mapeamento de Peptídeos/métodos , Proteômica/métodos , Animais , Cromatografia Líquida , Feminino , Glicosilação , Magnetismo , Espectrometria de Massas , Camundongos , Mapeamento de Peptídeos/instrumentação , Proteômica/instrumentação
20.
Glycobiology ; 21(7): 895-902, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21325337

RESUMO

Cell-surface carbohydrates are known to participate in many important physiological and pathological activities by interacting with their corresponding proteins or receptors. Although several methods have been developed for studying carbohydrate-protein interactions, one major problem originates from the weak bindings of carbohydrates/proteins that are often lost during repeating wash steps. Herein, we established a homogeneous solution carbohydrate array in which polyacrylamide-based glycans are used for offering a multivalent environment. The method requires no wash step and can be carried out in a high-throughput manner. We characterized the carbohydrate-binding specificities of 11 lectins and 7 antibodies, the majority of which displayed the binding patterns in consistence with previous reports. These results demonstrate that our developed solution carbohydrate array provides a useful alternative that is better than or comparable with the current available methods.


Assuntos
Anticorpos/metabolismo , Lectinas/metabolismo , Fármacos Fotossensibilizantes , Polissacarídeos/metabolismo , Proteínas/metabolismo , Resinas Acrílicas/metabolismo , Anticorpos/química , Humanos , Lectinas/química , Análise em Microsséries , Polissacarídeos/química , Ligação Proteica , Proteínas/química
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