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1.
PLoS Biol ; 21(4): e3002065, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-37058530

RESUMO

CRISPR-mediated interference relies on complementarity between a guiding CRISPR RNA (crRNA) and target nucleic acids to provide defense against bacteriophage. Phages escape CRISPR-based immunity mainly through mutations in the protospacer adjacent motif (PAM) and seed regions. However, previous specificity studies of Cas effectors, including the class 2 endonuclease Cas12a, have revealed a high degree of tolerance of single mismatches. The effect of this mismatch tolerance has not been extensively studied in the context of phage defense. Here, we tested defense against lambda phage provided by Cas12a-crRNAs containing preexisting mismatches against the genomic targets in phage DNA. We find that most preexisting crRNA mismatches lead to phage escape, regardless of whether the mismatches ablate Cas12a cleavage in vitro. We used high-throughput sequencing to examine the target regions of phage genomes following CRISPR challenge. Mismatches at all locations in the target accelerated emergence of mutant phage, including mismatches that greatly slowed cleavage in vitro. Unexpectedly, our results reveal that a preexisting mismatch in the PAM-distal region results in selection of mutations in the PAM-distal region of the target. In vitro cleavage and phage competition assays show that dual PAM-distal mismatches are significantly more deleterious than combinations of seed and PAM-distal mismatches, resulting in this selection. However, similar experiments with Cas9 did not result in emergence of PAM-distal mismatches, suggesting that cut-site location and subsequent DNA repair may influence the location of escape mutations within target regions. Expression of multiple mismatched crRNAs prevented new mutations from arising in multiple targeted locations, allowing Cas12a mismatch tolerance to provide stronger and longer-term protection. These results demonstrate that Cas effector mismatch tolerance, existing target mismatches, and cleavage site strongly influence phage evolution.


Assuntos
Bacteriófagos , Sistemas CRISPR-Cas , Sistemas CRISPR-Cas/genética , Bacteriófagos/genética , DNA/genética , RNA/genética , Mutação/genética
2.
Nucleic Acids Res ; 52(16): 9343-9359, 2024 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-39019776

RESUMO

Cas12a is the immune effector of type V-A CRISPR-Cas systems and has been co-opted for genome editing and other biotechnology tools. The specificity of Cas12a has been the subject of extensive investigation both in vitro and in genome editing experiments. However, in vitro studies have often been performed at high magnesium ion concentrations that are inconsistent with the free Mg2+ concentrations that would be present in cells. By profiling the specificity of Cas12a orthologs at a range of Mg2+ concentrations, we find that Cas12a switches its specificity depending on metal ion concentration. Lowering Mg2+ concentration decreases cleavage defects caused by seed mismatches, while increasing the defects caused by PAM-distal mismatches. We show that Cas12a can bind seed mutant targets more rapidly at low Mg2+ concentrations, resulting in faster cleavage. In contrast, PAM-distal mismatches cause substantial defects in cleavage following formation of the Cas12a-target complex at low Mg2+ concentrations. We observe differences in Cas12a specificity switching between three orthologs that results in variations in the routes of phage escape from Cas12a-mediated immunity. Overall, our results reveal the importance of physiological metal ion conditions on the specificity of Cas effectors that are used in different cellular environments.


CRISPR-Cas systems are commonly used for biotechnology. Their specificity has been studied extensively and has previously been thought to be well understood. In this work, we asked a simple question about the effect of metal ion concentration on CRISPR specificity; the results are surprising and striking. At the actual metal ion concentrations found in cells, Cas12a specificity is inverted in comparison to the higher metal ion conditions that are typically used in test-tube assays. The specificity observed at lower metal ion concentration is more relevant under cellular conditions.


Assuntos
Proteínas Associadas a CRISPR , Sistemas CRISPR-Cas , Magnésio , Magnésio/metabolismo , Magnésio/química , Proteínas Associadas a CRISPR/metabolismo , Proteínas Associadas a CRISPR/genética , Edição de Genes/métodos , Endodesoxirribonucleases/metabolismo , Endodesoxirribonucleases/genética , Especificidade por Substrato , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética
3.
Chem Res Toxicol ; 37(5): 757-770, 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38625865

RESUMO

Per- and polyfluoroalkyl substances (PFAS) are known for their high environmental persistence and potential toxicity. The presence of PFAS has been reported in many dairy products. However, the mechanisms underlying the accumulation of PFAS in these products remain unclear. Here, we used native mass spectrometry and molecular dynamics simulations to probe the interactions between 19 PFAS of environmental concern and two isoforms of the major bovine whey protein ß-lactoglobulin (ß-LG). We observed that six of these PFAS bound to both protein isoforms with low- to mid-micromolar dissociation constants. Based on quantitative, competitive binding experiments with endogenous ligands, PFAS can bind orthosterically and preferentially to ß-LG's hydrophobic ligand-binding calyx. ß-Cyclodextrin can also suppress binding of PFAS to ß-LG owing to the ability of ß-cyclodextrin to directly sequester PFAS from solution. This research sheds light on PFAS-ß-LG binding, suggesting that such interactions could impact lipid-fatty acid transport in bovine mammary glands at high PFAS concentrations. Furthermore, our results highlight the potential use of ß-cyclodextrin in mitigating PFAS binding, providing insights toward the development of strategies to reduce PFAS accumulation in dairy products and other biological systems.


Assuntos
Fluorocarbonos , Lactoglobulinas , Leite , Animais , Lactoglobulinas/metabolismo , Lactoglobulinas/química , Bovinos , Leite/química , Leite/metabolismo , Fluorocarbonos/química , Fluorocarbonos/metabolismo , Simulação de Dinâmica Molecular , beta-Ciclodextrinas/química , beta-Ciclodextrinas/metabolismo , Sítios de Ligação , Ligação Proteica
4.
Chem Rev ; 122(8): 7327-7385, 2022 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-34449207

RESUMO

Small molecule drug discovery has been propelled by the continual development of novel scientific methodologies to occasion therapeutic advances. Although established biophysical methods can be used to obtain information regarding the molecular mechanisms underlying drug action, these approaches are often inefficient, low throughput, and ineffective in the analysis of heterogeneous systems including dynamic oligomeric assemblies and proteins that have undergone extensive post-translational modification. Native mass spectrometry can be used to probe protein-small molecule interactions with unprecedented speed and sensitivity, providing unique insights into polydisperse biomolecular systems that are commonly encountered during the drug discovery process. In this review, we describe potential and proven applications of native MS in the study of interactions between small, drug-like molecules and proteins, including large multiprotein complexes and membrane proteins. Approaches to quantify the thermodynamic and kinetic properties of ligand binding are discussed, alongside a summary of gas-phase ion activation techniques that have been used to interrogate the structure of protein-small molecule complexes. We additionally highlight some of the key areas in modern drug design for which native mass spectrometry has elicited significant advances. Future developments and applications of native mass spectrometry in drug discovery workflows are identified, including potential pathways toward studying protein-small molecule interactions on a whole-proteome scale.


Assuntos
Descoberta de Drogas , Proteoma , Descoberta de Drogas/métodos , Espectrometria de Massas/métodos , Proteínas de Membrana , Termodinâmica
5.
J Cancer Educ ; 39(3): 335-348, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38594385

RESUMO

Cancer survivors including Asian American breast cancer survivors have reported their high needs for help during their survivorship process. With the COVID-19 pandemic, the necessity of technology-based programs to address their needs for help without face-to-face interactions has been highlighted. The purpose of this randomized intervention study was to determine the efficacy of a technology-based program in reducing various types of needs for help among this specific population. This was a randomized clinical trial with repeated measures. A total of 199 participants were included in the data analysis. The recruitment settings included both online and offline communities/groups for Asian Americans. The needs for help were assessed using the Support Care Needs Survey-34 Short Form (SCNS) subscales measuring psychological, information, physical, support, and communication needs. Data analysis was conducted through an intent-to-treat approach. In the mixed effect models, psychological needs, information needs, physical needs, and communication needs decreased over time (P < .001). However, there were no significant group * time effects. Social support significantly mediated the effects of a technology-based intervention on psychological, information, and support needs at the pre-test and the post-1 month. This study supported significant decreases in the needs for help of Asian American breast cancer survivors by a technology-based intervention. Further studies are needed with other racial/ethnic groups of cancer survivors to confirm the efficacy of a technology-based intervention in reducing cancer survivors' needs for help during their survivorship process.


Assuntos
Asiático , Neoplasias da Mama , COVID-19 , Sobreviventes de Câncer , Apoio Social , Humanos , Feminino , Neoplasias da Mama/etnologia , Neoplasias da Mama/psicologia , Neoplasias da Mama/terapia , Sobreviventes de Câncer/psicologia , Asiático/psicologia , Pessoa de Meia-Idade , COVID-19/prevenção & controle , COVID-19/epidemiologia , Avaliação das Necessidades , Adulto , SARS-CoV-2 , Necessidades e Demandas de Serviços de Saúde , Idoso , Inquéritos e Questionários
6.
PLoS Pathog ; 16(5): e1008576, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32392230

RESUMO

Yersinia suppress neutrophil responses by using a type 3 secretion system (T3SS) to inject 6-7 Yersinia effector proteins (Yops) effectors into their cytoplasm. YopH is a tyrosine phosphatase that causes dephosphorylation of the adaptor protein SKAP2, among other targets in neutrophils. SKAP2 functions in reactive oxygen species (ROS) production, phagocytosis, and integrin-mediated migration by neutrophils. Here we identify essential neutrophil functions targeted by YopH, and investigate how the interaction between YopH and SKAP2 influence Yersinia pseudotuberculosis (Yptb) survival in tissues. The growth defect of a ΔyopH mutant was restored in mice defective in the NADPH oxidase complex, demonstrating that YopH is critical for protecting Yptb from ROS during infection. The growth of a ΔyopH mutant was partially restored in Skap2-deficient (Skap2KO) mice compared to wild-type (WT) mice, while induction of neutropenia further enhanced the growth of the ΔyopH mutant in both WT and Skap2KO mice. YopH inhibited both ROS production and degranulation triggered via integrin receptor, G-protein coupled receptor (GPCR), and Fcγ receptor (FcγR) stimulation. SKAP2 was required for integrin receptor and GPCR-mediated ROS production, but dispensable for degranulation under all conditions tested. YopH blocked SKAP2-independent FcγR-stimulated phosphorylation of the proximal signaling proteins Syk, SLP-76, and PLCγ2, and the more distal signaling protein ERK1/2, while only ERK1/2 phosphorylation was dependent on SKAP2 following integrin receptor activation. These findings reveal that YopH prevents activation of both SKAP2-dependent and -independent neutrophilic defenses, uncouple integrin- and GPCR-dependent ROS production from FcγR responses based on their SKAP2 dependency, and show that SKAP2 is not required for degranulation.


Assuntos
Proteínas da Membrana Bacteriana Externa/imunologia , Peptídeos e Proteínas de Sinalização Intracelular/imunologia , Neutrófilos/imunologia , Proteínas Tirosina Fosfatases/imunologia , Transdução de Sinais/imunologia , Infecções por Yersinia pseudotuberculosis/imunologia , Yersinia pseudotuberculosis/imunologia , Animais , Peptídeos e Proteínas de Sinalização Intracelular/genética , Sistema de Sinalização das MAP Quinases/genética , Sistema de Sinalização das MAP Quinases/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Neutrófilos/patologia , Espécies Reativas de Oxigênio/imunologia , Transdução de Sinais/genética , Yersinia pseudotuberculosis/patogenicidade , Infecções por Yersinia pseudotuberculosis/genética , Infecções por Yersinia pseudotuberculosis/patologia
7.
CA Cancer J Clin ; 65(5): 384-400, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26186412

RESUMO

This article provides an overview of the current literature on seven cancer sites that may disproportionately affect lesbian, gay, bisexual, transgender/transsexual, and queer/questioning (LGBTQ) populations. For each cancer site, the authors present and discuss the descriptive statistics, primary prevention, secondary prevention and preclinical disease, tertiary prevention and late-stage disease, and clinical implications. Finally, an overview of psychosocial factors related to cancer survivorship is offered as well as strategies for improving access to care.


Assuntos
Bissexualidade/estatística & dados numéricos , Homossexualidade Feminina/estatística & dados numéricos , Homossexualidade/estatística & dados numéricos , Neoplasias/epidemiologia , Pessoas Transgênero/estatística & dados numéricos , Feminino , Saúde Global , Humanos , Masculino , Morbidade/tendências , Taxa de Sobrevida/tendências
8.
Sensors (Basel) ; 22(4)2022 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-35214306

RESUMO

In the early 2020s, the coronavirus pandemic brought the notion of remotely connected care to the general population across the globe. Oftentimes, the timely provisioning of access to and the implementation of affordable care are drivers behind tele-healthcare initiatives. Tele-healthcare has already garnered significant momentum in research and implementations in the years preceding the worldwide challenge of 2020, supported by the emerging capabilities of communication networks. The Tactile Internet (TI) with human-in-the-loop is one of those developments, leading to the democratization of skills and expertise that will significantly impact the long-term developments of the provisioning of care. However, significant challenges remain that require today's communication networks to adapt to support the ultra-low latency required. The resulting latency challenge necessitates trans-disciplinary research efforts combining psychophysiological as well as technological solutions to achieve one millisecond and below round-trip times. The objective of this paper is to provide an overview of the benefits enabled by solving this network latency reduction challenge by employing state-of-the-art Time-Sensitive Networking (TSN) devices in a testbed, realizing the service differentiation required for the multi-modal human-machine interface. With completely new types of services and use cases resulting from the TI, we describe the potential impacts on remote surgery and remote rehabilitation as examples, with a focus on the future of tele-healthcare in rural settings.


Assuntos
Infecções por Coronavirus , Telemedicina , Atenção à Saúde , Humanos , Internet , Pandemias , Telemedicina/métodos , Tato
9.
J Am Chem Soc ; 143(50): 21379-21387, 2021 12 22.
Artigo em Inglês | MEDLINE | ID: mdl-34886668

RESUMO

The structural diversity of natural products offers unique opportunities for drug discovery, but challenges associated with their isolation and screening can hinder the identification of drug-like molecules from complex natural product extracts. Here we introduce a mass spectrometry-based approach that integrates untargeted metabolomics with multistage, high-resolution native mass spectrometry to rapidly identify natural products that bind to therapeutically relevant protein targets. By directly screening crude natural product extracts containing thousands of drug-like small molecules using a single, rapid measurement, we could identify novel natural product ligands of human drug targets without fractionation. This method should significantly increase the efficiency of target-based natural product drug discovery workflows.


Assuntos
Produtos Biológicos/química , Ligantes , Proteínas/química , Produtos Biológicos/metabolismo , Anidrase Carbônica I/química , Anidrase Carbônica I/metabolismo , Cromatografia Líquida de Alta Pressão , Humanos , Metabolômica/métodos , Proteínas/metabolismo , Espectrometria de Massas em Tandem
10.
Sex Transm Dis ; 48(9): 643-647, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34110754

RESUMO

BACKGROUND: Despite high frequencies of oral and receptive anal intercourse among young women, the Centers for Disease Control and Prevention does not recommend routine oropharyngeal or anorectal screening for CT and GC. Risk-based extragenital screening of women has not been adopted at the majority of college health centers, and existing research has not focused on the female or college population. METHODS: We examined health records of women at a college health center in a large urban university for 3 years to evaluate the effectiveness of CT and GC screening. We also evaluated the proportion of CT and GC infections that would have been missed if risk-based extragenital screening was not performed. Decisions to screen at extragenital sites were based on patient-reported risk behavior. RESULTS: For 8027 unique chlamydia screens and 7907 unique gonorrhea screens, approximately 20% of the visits used extragenital screening in response to self-reported risk behaviors. More than 44% of patients were non-Hispanic White, and approximately 48% fell within the 20- to 24-year age group. The case positivity rates for CT were 2.85% with urogenital-only screening and 1.30% with risk-prompted extragenital screening (1.1% throat, 4.3% rectal). The case positivity rates for GC were 0.11% with urogenital-only screening and 0.37% with risk-prompted extragenital screening (0.37% throat, 0% rectal). If the college health center had relied solely on urogenital screening rather than adding risk-based extragenital screening, 4.41% of CT infections would have been missed and 28.57% of GC infections would have been missed. CONCLUSIONS: Nearly 1 of 22 CT infections and nearly 1 of 3 GC infections would have been missed without extragenital screening in this analysis of college women. Inclusion of risk-prompted extragenital screening in asymptomatic STD screening protocols can help clinicians diagnose CT and GC infections that would be have been missed with urogenital-only screening. Although rectal GC infections among women seem to be less common, oropharyngeal testing, in particular, for GC is suggested for women based on sexual risk. However, clinicians might only identify these risks if they ask patients directly about these potential exposures. Because guidelines exist only for men, future studies should focus on extragenital screening in college women to build the evidence that this particular population of patients may benefit from this practice, given the high risk of STDs in young adults.


Assuntos
Infecções por Chlamydia , Gonorreia , Infecções por Chlamydia/diagnóstico , Infecções por Chlamydia/epidemiologia , Chlamydia trachomatis/genética , Feminino , Gonorreia/diagnóstico , Gonorreia/epidemiologia , Humanos , Masculino , Programas de Rastreamento , Neisseria gonorrhoeae/genética , Técnicas de Amplificação de Ácido Nucleico , Prevalência , Adulto Jovem
11.
Phys Chem Chem Phys ; 23(17): 10303-10310, 2021 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-33908512

RESUMO

Herein, we report a theoretical investigation of the electronic structure and magnetic properties in [(Cp2Me4HLn(THF))2(µ-N2˙)]- and [(Cp2Me4HLn)2(µ-N2˙)]- (THF = tetrahydrofuran, CpMe4H = tetramethylcyclopentadienyl, Ln = Tb, Dy) complexes [as reported in Demir et al., Nat. Commun., 8, 1-9, 2144 (2017)]. By ab initio methods, their magnetic blocking behaviors are successfully characterized allowing elucidation of the origin of the two blocking barriers observed experimentally. In addition, a detailed analysis of exchange wave functions explains why the blocking barrier of the Tb complexes is roughly twice as large as that of the Dy analogues, a fact which appears to be a general trend exhibited in this family of compounds.

12.
J Bacteriol ; 202(18)2020 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-32601072

RESUMO

The Pseudomonas aeruginosa type III secretion system (T3SS) needle comprised of multiple PscF subunits is essential for the translocation of effector toxins into human cells, facilitating the establishment and dissemination of infection. Mutations in the pscF gene provide resistance to the phenoxyacetamide (PhA) series of T3SS inhibitory chemical probes. To better understand PscF functions and interactions with PhA, alleles of pscF with 71 single mutations altering 49 of the 85 residues of the encoded protein were evaluated for their effects on T3SS phenotypes. Of these, 37% eliminated and 63% maintained secretion, with representatives of both evenly distributed across the entire protein. Mutations in 14 codons conferred a degree of PhA resistance without eliminating secretion, and all but one were in the alpha-helical C-terminal 25% of PscF. PhA-resistant mutants exhibited no cross-resistance to two T3SS inhibitors with different chemical scaffolds. Two mutations caused constitutive T3SS secretion. The pscF allele at its native locus, whether wild type (WT), constitutive, or PhA resistant, was dominant over other pscF alleles expressed from nonnative loci and promoters, but mixed phenotypes were observed in chromosomal ΔpscF strains with both WT and mutant alleles at nonnative loci. Some PhA-resistant mutants exhibited reduced translocation efficiency that was improved in a PhA dose-dependent manner, suggesting that PhA can bind to those resistant needles. In summary, these results are consistent with a direct interaction between PhA inhibitors and the T3SS needle, suggest a mechanism of blocking conformational changes, and demonstrate that PscF affects T3SS regulation, as well as carrying out secretion and translocation.IMPORTANCEP. aeruginosa effector toxin translocation into host innate immune cells is critical for the establishment and dissemination of P. aeruginosa infections. The medical need for new anti-P. aeruginosa agents is evident by the fact that P. aeruginosa ventilator-associated pneumonia is associated with a high mortality rate (40 to 69%) and recurs in >30% of patients, even with standard-of-care antibiotic therapy. The results described here confirm roles for the PscF needle in T3SS secretion and translocation and suggest that it affects regulation, possibly by interaction with T3SS regulatory proteins. The results also support a model of direct interaction of the needle with PhA and suggest that, with further development, members of the PhA series may prove useful as drugs for P. aeruginosa infection.


Assuntos
Proteínas de Bactérias/antagonistas & inibidores , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Pseudomonas aeruginosa/efeitos dos fármacos , Sistemas de Secreção Tipo III/antagonistas & inibidores , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Resistência Microbiana a Medicamentos/genética , Peptídeos e Proteínas de Sinalização Intercelular/genética , Mutação , Fenoxiacetatos/farmacologia , Pseudomonas aeruginosa/genética , Relação Estrutura-Atividade
13.
Anal Chem ; 92(6): 4614-4622, 2020 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-32096628

RESUMO

Perfluoroalkyl substances (PFASs) persist and are ubiquitous in the environment. The origins of PFAS toxicity and how they specifically affect the functions of proteins remain unclear. Herein, we report that PFASs can strongly inhibit the activity of human carbonic anhydrases (hCAs), which are ubiquitous enzymes that catalyze the hydration of CO2, are abundant in the blood and organs of mammals, and involved in pH regulation, ion homeostasis, and biosynthesis. The interactions between PFASs and hCAs were investigated using stopped-flow kinetic enzyme-inhibition measurements, native mass spectrometry (MS), and ligand-docking simulations. Narrow-bore emitters in native MS with inner diameters of ∼300 nm were used to directly and simultaneously measure the dissociation constants of 11 PFASs to an enzyme, which was not possible using conventional emitters. The data from native MS and stopped-flow measurements were in excellent agreement. Of 15 PFASs investigated, eight can inhibit at least one of four hCA isozymes (I, II, IX, and XII) with submicromolar inhibition constants, including perfluorooctanoic acid, perfluorooctanesulfonamide, and perfluorooctanesulfonic acid. Some PFASs, including those with both short and long perfluoromethylene chains, can effectively inhibit at least one hCA isozyme with low nanomolar inhibition constants.


Assuntos
Ácidos Alcanossulfônicos/farmacologia , Caprilatos/farmacologia , Inibidores da Anidrase Carbônica/farmacologia , Anidrases Carbônicas/metabolismo , Poluentes Ambientais/farmacologia , Fluorocarbonos/farmacologia , Ácidos Alcanossulfônicos/análise , Caprilatos/análise , Inibidores da Anidrase Carbônica/análise , Cristalografia por Raios X , Poluentes Ambientais/análise , Fluorocarbonos/análise , Humanos , Isoenzimas/antagonistas & inibidores , Isoenzimas/metabolismo , Ligantes , Espectrometria de Massas , Modelos Moleculares , Tamanho da Partícula , Propriedades de Superfície
14.
Anal Chem ; 92(1): 1130-1137, 2020 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-31778608

RESUMO

Netropsin is one of the first ligands to be discovered that selectively binds to the minor groove of DNA and is actively used as a scaffold for developing potential anticancer and antibiotic agents. The mechanism by which netropsin binds to hairpin DNA remains controversial with two competing mechanisms having been proposed. In one mechanism, netropsin binding induces a hairpin-to-duplex DNA transition. Alternatively, netropsin binds in two thermodynamically different modes at a single duplexed AATT site. Here, results from native mass spectrometry (MS) with nanoscale ion emitters indicate that netropsin can simultaneously and sequentially bind to both hairpin and duplex DNA. Duplex DNA was not detected using conventional MS with larger emitters because nanoscale emitters significantly reduce the extent of salt adduction to ligand-DNA complex ions, including in the presence of relatively high concentrations of nonvolatile salts. Based on native MS and polyacrylamide gel electrophoresis results, the abundances of hairpin and duplex DNA are unaffected by the addition of netropsin. By native MS, the binding affinities for five ligand-DNA and DNA-DNA interactions can be rapidly obtained simultaneously. This research indicates a "simultaneous binding mechanism" for the interactions of netropsin with DNA.


Assuntos
DNA/metabolismo , Netropsina/metabolismo , DNA/genética , Eletroforese em Gel de Poliacrilamida , Sequências Repetidas Invertidas , Ligação Proteica , Espectrometria de Massas por Ionização por Electrospray/métodos , Streptomyces/química
15.
Anal Chem ; 92(23): 15420-15428, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-33200920

RESUMO

Organophosphates (OPs) are used worldwide as pesticides. However, acute and chronic exposure to OPs can cause serious adverse health effects. The mechanism of delayed OP toxicity is thought to involve off-target inhibition of serine proteases, although the precise molecular details remain unclear owing to the lack of an analytical method for global detection of protein targets of OPs. Here, we report the development of a mass spectrometry method to identify OP-adducted proteins from complex mixtures in a nontargeted manner. Human plasma was incubated with the OP dichlorvos that was 50% isotopically labeled and 50% unlabeled. Proteins and protein adducts were extracted, digested, and analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) to detect "twin ions" of peptides that were covalently modified by a chemical reaction with dichlorvos. The LC-MS/MS data were processed by a blended data analytics software (Xenophile) to detect the amino acid residue sites of proteins that were covalently modified by exposure to OPs. We discovered that OPs can transmethylate the N, S, and O side chains of His, Cys, Glu, Asp, and Lys residues. For model systems, such transmethylation reactions were confirmed by LC-MS, nuclear magnetic resonance (NMR), and rationalized using electronic structure calculations. Methylation of the ubiquitous antioxidant glutathione by dichlorvos can decrease the reducing/oxidizing equilibrium of glutathione in liver extracts, which has been implicated in diseases and pathological conditions associated with delayed OP toxicity.


Assuntos
Proteínas Sanguíneas/química , Nitrogênio/química , Organofosfatos/química , Oxigênio/química , Enxofre/química , Cromatografia Líquida , Humanos , Metilação , Organofosfatos/toxicidade , Espectrometria de Massas em Tandem
16.
J Health Commun ; 23(12): 977-983, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30325705

RESUMO

In the United States, Asian Americans account for 50-60% of hepatitis B virus infections, leading to higher rates of liver cancer in this population. While some city-wide data have reported hepatitis B infection rates among young adults as high as 10-20%, little research has examined factors that impact hepatitis B beliefs, or the most effective strategies for reaching this particular population to promote hepatitis B awareness. An online survey was conducted with young Asian American adults (n = 418), aged 18-29 years old, to better understand their health information seeking, social media usage, and hepatitis B-related behaviors and beliefs. Results indicated that doctors and health organizations were the most trusted sources of health information, while the Internet was the most common source of health information. The majority of participants (99.8%) reported using social media and indicated they engaged in health-related behaviors on social media. Several factors, including non-receipt of hepatitis B vaccine, engaging in more health-related social media activities, and a higher mean score for difficulty with health information seeking, were significantly related to higher perceived susceptibility to hepatitis B. Future research should explore the effectiveness of using social media to reach young Asian American adults to promote hepatitis B awareness.


Assuntos
Asiático , Promoção da Saúde/métodos , Hepatite B/prevenção & controle , Adolescente , Adulto , Asiático/psicologia , Asiático/estatística & dados numéricos , Atitude Frente a Saúde/etnologia , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Hepatite B/etnologia , Vacinas contra Hepatite B/uso terapêutico , Humanos , Masculino , Mídias Sociais , Inquéritos e Questionários , Adulto Jovem
17.
Compr Rev Food Sci Food Saf ; 17(5): 1422-1445, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33350160

RESUMO

Starch digestion is mostly investigated with in vitro techniques, and time-course measurements are common. These yield digestograms that are modeled by theoretical, semitheoretical, and empirical kinetic equations, many of which are reviewed here. The Duggleby model has Michaelis-Menten functions, and its dependent variable is on both sides of the equation with no apparent parameter for maximum digestible starch (D∞ ). The Gaouar and Peleg models are equivalent. They predict both the initial digestible starch (D0 ) and D∞ , and an average digestion rate, but they can reveal "biratial" digestions. The first-order kinetic model exhibits diverse predictabilities and, when linearized, D∞ is sometimes equated to 100 g/100 g dry starch (100%), it yields an average rate of digestion and can predict negative D0 . The log of slope (LOS) model is unique in revealing the rapid-to-slow digestion rate phenomenon, but without guidelines to identify such. The LOS model does not sometimes use all the digestogram data, can predict D∞ greater than 100%, and returns zero digestion rate for some digestograms. However, some starchy materials exhibit a slow-to-rapid digestion rate phenomenon, as demonstrated with an example. The modified first-order kinetic model uses all the digestogram data with practical constraints (D0  ≥ 0 g/100 g dry starch; D∞  ≤ 100 g/100 g dry starch), describes all digestograms, and yields an average digestion rate, but it can also be used for "biratial" digestions. In addition, the logistic and Weibull models are discussed. Using some published data, the computational characteristics of these commonly used models are presented with objective parameters to guide choices.

18.
Appl Environ Microbiol ; 83(16)2017 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-28576761

RESUMO

Acute hepatopancreatic necrosis disease (AHPND) of shrimp is caused by Vibrio parahaemolyticus isolates (VPAHPND isolates) that harbor a pVA plasmid encoding toxins PirA Vp and PirB Vp These are released from VPAHPND isolates that colonize the shrimp stomach and produce pathognomonic AHPND lesions (massive sloughing of hepatopancreatic tubule epithelial cells). PCR results indicated that V. parahaemolyticus isolate XN87 lacked pirA Vp but carried pirB Vp Unexpectedly, Western blot analysis of proteins from the culture broth of XN87 revealed the absence of both toxins, and the lack of PirB Vp was further confirmed by enzyme-linked immunosorbent assay. However, shrimp immersion challenge with XN87 resulted in 47% mortality without AHPND lesions. Instead, lesions consisted of collapsed hepatopancreatic tubule epithelia. In contrast, control shrimp challenged with typical VPAHPND isolate 5HP gave 90% mortality, accompanied by AHPND lesions. Sequence analysis revealed that the pVA plasmid of XN87 contained a mutated pirA Vp gene interrupted by the out-of-frame insertion of a transposon gene fragment. The upstream region and the beginning of the original pirA Vp gene remained intact, but the insertion caused a 2-base reading frameshift in the remainder of the pirA Vp gene sequence and in the downstream pirB Vp gene sequence. Reverse transcription-PCR and sequencing of 5HP revealed a bicistronic pirAB Vp mRNA transcript that was not produced by XN87, explaining the absence of both toxins in its culture broth. However, the virulence of XN87 revealed that some V. parahaemolyticus isolates carrying mutant pVA plasmids that produce no Pir Vp toxins can cause mortality in shrimp in ponds experiencing an outbreak of early mortality syndrome (EMS) but may not have been previously recognized to be AHPND related because they did not cause pathognomonic AHPND lesions.IMPORTANCE Shrimp acute hepatopancreatic necrosis disease (AHPND) is caused by Vibrio parahaemolyticus isolates (VPAHPND isolates) that harbor the pVA1 plasmid encoding toxins PirA Vp and PirB Vp The toxins are produced in the shrimp stomach but cause death by massive sloughing of hepatopancreatic tubule epithelial cells (pathognomonic AHPND lesions). V. parahaemolyticus isolate XN87 harbors a mutant pVA plasmid that produces no Pir toxins and does not cause AHPND lesions but still causes ∼50% shrimp mortality. Such isolates may cause a portion of the mortality in ponds experiencing an outbreak of EMS that is not ascribed to VPAHPND Thus, they pose to shrimp farmers an additional threat that would be missed by current testing for VPAHPND Moribund shrimp from ponds experiencing an outbreak of EMS that exhibit collapsed hepatopancreatic tubule epithelial cells can serve as indicators for the possible presence of such isolates, which can then be confirmed by additional PCR tests for the presence of a pVA plasmid.

19.
Sex Transm Dis ; 44(5): 274-277, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28407642

RESUMO

BACKGROUND: Although the Centers for Disease Control and Prevention does not recommend routine oropharyngeal and anorectal screening for Chlamydia trachomatis and Neisseria gonorrhoeae in the general population, they do recommend it for men who have sex with men. However, risk-based extragenital screening of men may not have been adopted at all college health centers, and existing research has not focused on the college population. METHODS: We examined health records of men at a college health center in a large urban university over 6 years to evaluate effectiveness of C. trachomatis and N. gonorrhoeae screening. We also evaluated the proportion of C. trachomatis and N. gonorrhoeae infections that would have been missed if risk-based extragenital screening were not performed. Decisions to screen at extragenital sites were based on patient-reported risk behavior. RESULTS: For 4093 male college students screened, 7.6% of the screening visits used extragenital screening in response to self-reported risk behaviors. The case positivity rate for C. trachomatis was 3.1% with urogenital-only screening and 3.7% with risk-prompted extragenital screening. The case positivity rate for N. gonorrhoeae was 0.7% with urogenital-only screening and 3.3% with risk-prompted extragenital screening. If the college health center had relied solely on urogenital screening rather than risk-based extragenital screening, 26.4% of C. trachomatis infections and 63.2% of N. gonorrhoeae infections would have been missed. CONCLUSIONS: One out of four C. trachomatis infections and 2 of 3 N. gonorrhoeae infections would have been missed without extragenital screening in this analysis of college men. This study reinforces Centers for Disease Control and Prevention recommendations for risk-based extragenital screening and is the first report to focus on college men. Because guidelines exist only for men, future studies should focus on extragenital screening in college women to build evidence for another group of patients that may benefit from this practice, given the high risk in young adults.


Assuntos
Infecções por Chlamydia/diagnóstico , Chlamydia trachomatis/isolamento & purificação , Gonorreia/diagnóstico , Neisseria gonorrhoeae/isolamento & purificação , Adulto , Centers for Disease Control and Prevention, U.S. , Infecções por Chlamydia/epidemiologia , Infecções por Chlamydia/microbiologia , Estudos Transversais , Gonorreia/epidemiologia , Gonorreia/microbiologia , Humanos , Masculino , Prontuários Médicos , Estados Unidos/epidemiologia , Adulto Jovem
20.
J Cancer Educ ; 32(2): 374-381, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26621507

RESUMO

In the USA, cancer is the leading cause of death for Asian Americans and Pacific Islanders (AAPIs), but little is known about the unmet needs of AAPI cancer survivors, especially from a national perspective. Using a community-based participatory research approach, we partnered with the Asian and Pacific Islander National Cancer Survivors Network and the Asian American Cancer Support Network to design and conduct a cross-sectional survey to understand the unmet needs of a national sample of AAPI cancer survivors. We assessed unmet needs in 10 domains: day-to-day activities, financial expenses, emotional concerns, medical treatment, cancer information, home care, nutrition, physical concerns, family relationships, and spirituality. We also assessed self-reported measures related to quality of life. This national sample of AAPI cancer survivors included people from 14 states and two territories who had been diagnosed with a broad range of cancers, including cancer of the breast, ovary/uterus/cervix, prostate, blood, and other sites. Over 80 % reported at least one unmet need. Participants reported an average of 8.4 unmet needs, spanning an average of 3.9 domains. Most commonly reported were unmet needs pertaining to physical concerns (66 %), day-to-day activities (52 %), and emotional concerns (52 %). This is the first report of unmet needs in a national sample of AAPI cancer survivors with a range of different cancer types. It describes the areas of greatest need and points to the importance of devoting more resources to identifying and addressing unmet needs for the underserved population of AAPI cancer survivors.


Assuntos
Asiático/estatística & dados numéricos , Sobreviventes de Câncer/estatística & dados numéricos , Havaiano Nativo ou Outro Ilhéu do Pacífico/estatística & dados numéricos , Avaliação das Necessidades , Pesquisa Participativa Baseada na Comunidade , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Qualidade de Vida , Apoio Social
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