Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 34
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
PLoS Comput Biol ; 13(7): e1005639, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28715411

RESUMO

The Gram-negative bacterium Bordetella pertussis is the causative agent of whooping cough, a serious respiratory infection causing hundreds of thousands of deaths annually worldwide. There are effective vaccines, but their production requires growing large quantities of B. pertussis. Unfortunately, B. pertussis has relatively slow growth in culture, with low biomass yields and variable growth characteristics. B. pertussis also requires a relatively expensive growth medium. We present a new, curated flux balance analysis-based model of B. pertussis metabolism. We enhance the model with an experimentally-determined biomass objective function, and we perform extensive manual curation. We test the model's predictions with a genome-wide screen for essential genes using a transposon-directed insertional sequencing (TraDIS) approach. We test its predictions of growth for different carbon sources in the medium. The model predicts essentiality with an accuracy of 83% and correctly predicts improvements in growth under increased glutamate:fumarate ratios. We provide the model in SBML format, along with gene essentiality predictions.


Assuntos
Bordetella pertussis/genética , Bordetella pertussis/metabolismo , Genoma Bacteriano/genética , Modelos Biológicos , Fumaratos/metabolismo , Ácido Glutâmico/metabolismo , Humanos , Análise do Fluxo Metabólico , Curva ROC , Coqueluche/microbiologia
2.
Proc Natl Acad Sci U S A ; 111(17): 6407-12, 2014 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-24733938

RESUMO

The lengths of bacterial polysaccharides can be critical for their biological function. Unlike DNA or protein synthesis, where polymer length is implicit in the nucleic acid template, the molecular mechanisms for regulating polysaccharide length are poorly understood. Two models are commonly cited: a "molecular clock" regulates length by controlling the duration of the polymer extension process, whereas a "molecular ruler" determines length by measurement against a physical structure in the biosynthetic complex. Escherichia coli O9a is a prototype for the biosynthesis of O polysaccharides by ATP-binding cassette transporter-dependent processes. The length of the O9a polysaccharide is determined by two proteins: an extension enzyme, WbdA, and a termination enzyme, WbdD. WbdD is known to self-oligomerize and also to interact with WbdA. Changing either enzyme's concentration can alter the polysaccharide length. We quantified the O9a polysaccharide length distribution and the enzyme concentration dependence in vivo, then made mathematical models to predict the polymer length distributions resulting from hypothetical length-regulation mechanisms. Our data show qualitative features that cannot be explained by either a molecular clock or a molecular ruler model. Therefore, we propose a "variable geometry" model, in which a postulated biosynthetic WbdA-WbdD complex assembles with variable stoichiometry dependent on relative enzyme concentration. Each stoichiometry produces polymers with a distinct, geometrically determined, modal length. This model reproduces the enzyme concentration dependence and modality of the observed polysaccharide length distributions. Our work highlights limitations of previous models and provides new insight into the mechanisms of length control in polysaccharide biosynthesis.


Assuntos
Escherichia coli/metabolismo , Antígenos O/química , Proteínas de Escherichia coli/metabolismo , Manosiltransferases/metabolismo , Modelos Biológicos , Peso Molecular
3.
J Public Health Manag Pract ; 23(6): e25-e35, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28492448

RESUMO

CONTEXT: A national system of voluntary public health accreditation for state, local, and tribal health departments (local health departments [LHDs]) is part of a movement that aims to improve public health performance with ultimate impact on population health outcomes. Indiana is a good setting for the study of LHD accreditation adoption because several LHDs reported de-adopting accreditation in a recent statewide survey and because 71% of Indiana counties serve populations of 50 000 or less. DESIGN: A systematic method of analyzing qualitative data based on the Performance Improvement Model framework to expand our understanding of de-adoption of public health accreditation. SETTING/PARTICIPANTS: In 2015, we conducted a key informant interview study of the 3 LHDs that decided to delay their engagement in the accreditation based on findings from an Indiana survey on LHD accreditation adoption. The study is an exploration of LHD accreditation de-adoption and of the contributions made to its understanding by the Performance Improvement Model. RESULT: The study found that top management team members are those who champion accreditation adoption, and that organizational structure and culture facilitate the staff's embracing of the change. The Performance Improvement Model was found to enhance the elucidation of the inner domain elements of Consolidated Framework for Implementation Research in the context of de-adoption of public health accreditation. CONCLUSION: Governing entities' policies and priorities appear to mediate whether the LHDs are able to continue accreditation pursuit. Lacking any of these driving forces appears to be associated with decisions to de-adoption of accreditation. Further work is necessary to discern specific elements mediating decisions to pursue accreditation. This study demonstrates the added knowledge of Performance Improvement Model (PIM) to the CFIR framework. A large scale study is called to further clarify and discern supports of specific to the needs of individual LHDs for their performance improvement effort.


Assuntos
Acreditação/tendências , Saúde Pública/normas , Melhoria de Qualidade/organização & administração , Acreditação/métodos , Humanos , Indiana , Governo Local , Saúde Pública/métodos , Administração em Saúde Pública/métodos , Administração em Saúde Pública/normas , Pesquisa Qualitativa , Melhoria de Qualidade/tendências , Inquéritos e Questionários
4.
J Biol Chem ; 290(42): 25561-70, 2015 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-26330553

RESUMO

Lysogenic bacteriophages may encode enzymes that modify the structures of lipopolysaccharide O-antigen glycans, altering the structure of the bacteriophage receptor and resulting in serotype conversion. This can enhance virulence and has implications for antigenic diversity and vaccine development. Side chain glucosylation is a common modification strategy found in a number of bacterial species. To date, glucosylation has only been observed in O-antigens synthesized by Wzy-dependent pathways, one of the two most prevalent O-antigen synthesis systems. Here we exploited a heterologous system to study the glucosylation potential of a model O-antigen produced in an ATP-binding cassette (ABC) transporter-dependent system. Although O-antigen production is cryptic in Escherichia coli K-12, because of a mutation in the synthesis genes, it possesses a prophage glucosylation cluster, which modifies the GlcNAc residue in an α-l-Rha-(1→3)-d-GlcNAc motif found in the original O16 antigen. Raoultella terrigena ATCC 33257 produces an O-antigen possessing the same disaccharide motif, but its assembly uses an ABC transporter-dependent system. E. coli harboring the R. terrigena O-antigen biosynthesis genes produced an O-antigen displaying reduced reactivity toward antisera raised against the native R. terrigena repeat structure, indicative of an altered chemical structure. Structural determination using NMR revealed the addition of glucose side chains to the repeat units. O-antigen modification was dependent on a functional ABC transporter, consistent with modification in the periplasm, and was eliminated by deletion of the glucosylation genes from the E. coli chromosome, restoring native level antisera sensitivity and structure. There are therefore no intrinsic mechanistic barriers for bacteriophage-mediated O-antigen glucosylation in ABC transporter-dependent pathways.


Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Bacteriófagos/fisiologia , Antígenos O/metabolismo , Bacteriófagos/genética , Configuração de Carboidratos , Sequência de Carboidratos , Enterobacteriaceae , Glicosilação , Dados de Sequência Molecular , Antígenos O/biossíntese , Antígenos O/química
5.
Proc Natl Acad Sci U S A ; 108(10): 4087-92, 2011 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-21367691

RESUMO

Pertussis is a highly contagious respiratory disease that is especially dangerous for infants and children. Despite mass vaccination, reported pertussis cases have increased in the United States and other parts of the world, probably because of increased awareness, improved diagnostic means, and waning vaccine-induced immunity among adolescents and adults. Licensed vaccines do not kill the organism directly; the addition of a component inducing bactericidal antibodies would improve vaccine efficacy. We investigated Bordetella pertussis and Bordetella bronchiseptica LPS-derived core oligosaccharide (OS) protein conjugates for their immunogenicity in mice. B. pertussis and B. bronchiseptica core OS were bound to aminooxylated BSA via their terminal Kdo residues. The two conjugates induced similar anti-B. pertussis LPS IgG levels in mice. B. bronchiseptica was investigated because it is easier to grow than B. pertussis. Using B. bronchiseptica genetically modified strains deficient in the O-specific polysaccharide, we isolated fractions of core OS with one to five repeats of the terminal trisaccharide, having at the nonreducing end a GlcNAc or GalNAc, and bound them to BSA at different densities. The highest antibody levels in mice were elicited by conjugates containing an average of 8-17 OS chains per protein and with one repeat of the terminal trisaccharide. Conjugate-induced antisera were bactericidal against B. pertussis, and the titers correlated with ELISA-measured antibody levels (r = 0.74). Such conjugates are easy to prepare and standardize; added to a recombinant pertussis toxoid, they may induce antibacterial and antitoxin immunity.


Assuntos
Anticorpos Antibacterianos/biossíntese , Bordetella bronchiseptica/metabolismo , Bordetella pertussis/metabolismo , Oligossacarídeos/metabolismo , Vacina contra Coqueluche/administração & dosagem , Animais , Bordetella bronchiseptica/imunologia , Bordetella pertussis/imunologia , Sequência de Carboidratos , Eletroforese em Gel de Poliacrilamida , Feminino , Camundongos , Dados de Sequência Molecular , Oligossacarídeos/química , Vacina contra Coqueluche/imunologia , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
6.
J Biol Chem ; 285(35): 26869-26877, 2010 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-20592026

RESUMO

The O chain polysaccharide (O PS) of Bordetella bronchiseptica and Bordetella parapertussis lipopolysaccharide is a homopolymer of 2,3-diacetamido-2,3-dideoxygalacturonic acid (GalNAc3NAcA) in which some of the sugars are present as uronamides. The terminal residue contains several unusual modifications. To date, two types of modification have been characterized, and a survey of numerous strains demonstrated that each contained one of these two modification types. Host antibody responses against the O PS are directed against the terminal residue modifications, and there is little cross-reactivity between the two types. This suggests that Bordetella O PS modifications represent a means of antigenic variation. Here we report the characterization of the O PS of B. bronchiseptica strain MO149. It consists of a novel two-sugar repeating unit and a novel terminal residue modification, with the structure Me-4-alpha-L-GalNAc3NAcA-(4-beta-D-GlcNAc3NAcA-4-alpha-L-GalNAc3NAcA-)(5-6)-, which we propose be defined as the B. bronchiseptica O3 PS. We show that the O3 PS is very poorly immunogenic and that the MO149 strain contains a novel wbm (O PS biosynthesis) locus. Thus, there is greater diversity among Bordetella O PSs than previously recognized, which is likely to be a result of selection pressure from host immunity. We also determine experimentally, for the first time, the absolute configuration of the diacetimido-uronic acid sugars in Bordetella O PS.


Assuntos
Antígenos de Bactérias/imunologia , Bordetella bronchiseptica/imunologia , Lipopolissacarídeos/imunologia , Animais , Antígenos de Bactérias/química , Antígenos de Bactérias/genética , Bordetella bronchiseptica/química , Bordetella bronchiseptica/genética , Configuração de Carboidratos , Loci Gênicos , Lipopolissacarídeos/química , Lipopolissacarídeos/genética , Camundongos
7.
Biol Blood Marrow Transplant ; 16(4): 443-68, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20114084

RESUMO

Clinical research examining the role of hematopoietic stem cell transplantation (SCT) in the therapy of follicular non-Hodgkin lymphoma in adults is presented and critically evaluated in this systematic evidence-based review. Specific criteria were used for searching the published literature and for grading the quality and strength of the evidence and the strength of the treatment recommendations. Treatment recommendations reached unanimously by a panel of follicular lymphoma experts are: (1) autologous SCT is recommended as salvage therapy based on pre-rituximab data, with a significant improvement in overall survival (OS) and progression-free (PFS) survival; (2) autologous SCT is not recommended as first-line treatment for most patients because of no significant improvement in OS; (3) autologous SCT is recommended for transformed follicular lymphoma patients; (4) reduced intensity conditioning before allogeneic SCT appears to be an acceptable alternative to myeloablative regimens; (5) an HLA-matched unrelated donor appears to be as effective an HLA-matched related donor for reduced intensity conditioning allogeneic SCT. There are insufficient data to make a recommendation on the use of autologous SCT after rituximab-based salvage therapy. Eleven areas of needed research in the treatment of follicular lymphoma with SCT were identified and are presented in the review.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Transplante de Células-Tronco Hematopoéticas/métodos , Linfoma Folicular/terapia , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais Murinos , Terapia Combinada , Medicina Baseada em Evidências , Humanos , Linfoma Folicular/tratamento farmacológico , Linfoma Folicular/cirurgia , Prognóstico , Rituximab , Condicionamento Pré-Transplante
8.
Environ Microbiol ; 12(6): 1531-44, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20192967

RESUMO

The major component of the outer leaflet of the outer membrane of Gram-negative bacteria is lipopolysaccharide (LPS). The outermost domain of LPS is a polysaccharide called O antigen. Pseudomonas aeruginosa establishes biofilms on wet surfaces in a wide range of habitats and mutations in O-antigen biosynthesis genes affect bacterial adhesion and the structure of these biofilms. The P. aeruginosa O6 O antigen contains a 2-acetamido-2-deoxy-d-galacturonamide (d-GalNAcAN) residue. O-antigen biosynthesis in this serotype requires the wbpS gene, which encodes a protein with conserved domains of the glutamine-dependent amidotransferase family. Replacement of conserved amino acids in the N-terminal glutaminase conserved domain of WbpS inhibited O-antigen biosynthesis under restricted-ammonia conditions, but not in rich media; suggesting that this domain functions to provide ammonia for O-antigen biosynthesis under restricted-ammonia conditions, by hydrolysis of glutamine. Escherichia coli O121 also produces a d-GalNAcAN-containing O antigen, and possesses a homologue of wbpS called wbqG. An E. coli O121 wbqG mutant was cross-complemented by providing wbpS in trans, and vice versa, showing that these two genes are functionally interchangeable. The E. coli O121 wbqG mutant O antigen contains 2-acetamido-2-deoxy-d-galacturonate (d-GalNAcA), instead of d-GalNAcAN, demonstrating that wbqG is specifically required for biosynthesis of the carboxamide in this sugar.


Assuntos
Escherichia coli/metabolismo , Antígenos O/biossíntese , Antígenos O/química , Pseudomonas aeruginosa/metabolismo , Ácidos Urônicos/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Configuração de Carboidratos , Sequência de Carboidratos , Escherichia coli/citologia , Escherichia coli/genética , Teste de Complementação Genética , Glutaminase/metabolismo , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Mutação , Antígenos O/imunologia , Pseudomonas aeruginosa/citologia , Pseudomonas aeruginosa/genética , Ácidos Urônicos/química
9.
Microb Genom ; 6(12)2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33295860

RESUMO

The identification of genes essential for a bacterium's growth reveals much about its basic physiology under different conditions. Bordetella pertussis, the causative agent of whooping cough, adopts both virulent and avirulent states through the activity of the two-component system, Bvg. The genes essential for B. pertussis growth in vitro were defined using transposon sequencing, for different Bvg-determined growth states. In addition, comparison of the insertion indices of each gene between Bvg phases identified those genes whose mutation exerted a significantly different fitness cost between phases. As expected, many of the genes identified as essential for growth in other bacteria were also essential for B. pertussis. However, the essentiality of some genes was dependent on Bvg. In particular, a number of key cell wall biosynthesis genes, including the entire mre/mrd locus, were essential for growth of the avirulent (Bvg minus) phase but not the virulent (Bvg plus) phase. In addition, cell wall biosynthesis was identified as a fundamental process that when disrupted produced greater fitness costs for the Bvg minus phase compared to the Bvg plus phase. Bvg minus phase growth was more susceptible than Bvg plus phase growth to the cell wall-disrupting antibiotic ampicillin, demonstrating the increased susceptibility of the Bvg minus phase to disruption of cell wall synthesis. This Bvg-dependent conditional essentiality was not due to Bvg-regulation of expression of cell wall biosynthesis genes; suggesting that this fundamental process differs between the Bvg phases in B. pertussis and is more susceptible to disruption in the Bvg minus phase. The ability of a bacterium to modify its cell wall synthesis is important when considering the action of antibiotics, particularly if developing novel drugs targeting cell wall synthesis.


Assuntos
Bordetella pertussis/crescimento & desenvolvimento , Genes Essenciais , Análise de Sequência de DNA/métodos , Proteínas de Bactérias/genética , Bordetella pertussis/genética , Elementos de DNA Transponíveis , Regulação Bacteriana da Expressão Gênica , Mutagênese Sítio-Dirigida , Mutação , Fatores de Transcrição/genética
10.
Emerg Microbes Infect ; 8(1): 603-612, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30966996

RESUMO

Whooping cough, or pertussis, is resurgent in numerous countries worldwide. This has renewed interest in Bordetella pertussis biology and vaccinology. The in vitro growth of B. pertussis has been a source of difficulty, both for the study of the organism and the production of pertussis vaccines. It is inhibited by fatty acids and other hydrophobic molecules. The AcrAB efflux system is present in many different bacteria and in combination with an outer membrane factor exports acriflavine and other small hydrophobic molecules from the cell. Here, we identify that the speciation of B. pertussis has selected for an Acr system that is naturally mutated and displays reduced activity compared to B. bronchiseptica, in which the system appears intact. Replacement of the B. pertussis locus with that of B. bronchiseptica conferred higher levels of resistance to growth inhibition by acriflavine and fatty acids. In addition, we identified that the transcription of the locus is repressed by a LysR-type transcriptional regulator. Palmitate de-represses the expression of the acr locus, dependent on the LysR regulator, strongly suggesting that it is a transcriptional repressor that is regulated by palmitate. It is intriguing that the speciation of B. pertussis has selected for a reduction in activity of the Acr efflux system that typically is regarded as protective to bacteria.


Assuntos
Acriflavina/metabolismo , Proteínas de Bactérias/genética , Bordetella pertussis/genética , Evolução Molecular , Ácidos Graxos/metabolismo , Regulação Bacteriana da Expressão Gênica , Coqueluche/microbiologia , Acriflavina/química , Proteínas de Bactérias/metabolismo , Bordetella pertussis/crescimento & desenvolvimento , Bordetella pertussis/metabolismo , Ácidos Graxos/química , Interações Hidrofóbicas e Hidrofílicas , Mutação
11.
J Bacteriol ; 190(5): 1671-9, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18156256

RESUMO

The rare sugar 2,6-dideoxy-2-acetamidino-L-galactose (L-FucNAm) is found only in bacteria and is a component of cell surface glycans in a number of pathogenic species, including the O antigens of Pseudomonas aeruginosa serotype O12 and Escherichia coli O145. P. aeruginosa is an important opportunistic pathogen, and the O12 serotype is associated with multidrug-resistant epidemic outbreaks. O145 is one of the classic non-O157 serotypes associated with Shiga toxin-producing, enterohemorrhagic E. coli. The acetamidino (NAm) moiety of L-FucNAm is of interest, because at neutral pH it contributes a positive charge to the cell surface, and we aimed to characterize the biosynthesis of this functional group. The pathway is not known, but expression of NAm-modified sugars coincides with the presence of a pseA homologue in the relevant biosynthetic locus. PseA is a putative amidotransferase required for synthesis of a NAm-modified sugar in Campylobacter jejuni. In P. aeruginosa O12 and E. coli O145, the pseA homologues are lfnA and wbuX, respectively, and we hypothesized that these genes function in L-FucNAm biosynthesis. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western blotting, and nuclear magnetic resonance analysis of the lfnA mutant O-antigen structure indicated that the mutant expresses 2,6-dideoxy-2-acetamido-L-galactose (L-FucNAc) in place of L-FucNAm. The mutation could be complemented by expression of either His(6)-tagged lfnA or wbuX in trans, confirming that these genes are functional homologues and that they are required for NAm moiety synthesis. Both proteins retained their activity when fused to a His(6) tag and localized to the membrane fraction. These data will assist future biochemical investigation of this pathway.


Assuntos
Proteínas de Bactérias/metabolismo , Escherichia coli/metabolismo , Galactose/metabolismo , Antígenos O/metabolismo , Pseudomonas aeruginosa/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/fisiologia , Western Blotting , Sequência de Carboidratos , Cromatografia em Gel , Cromatografia por Troca Iônica , Biologia Computacional , Eletroforese em Gel de Poliacrilamida , Eletroporação , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Galactose/química , Teste de Complementação Genética , Espectroscopia de Ressonância Magnética , Dados de Sequência Molecular , Mutagênese , Mutação , Antígenos O/química , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/crescimento & desenvolvimento
12.
Artigo em Inglês | MEDLINE | ID: mdl-17671375

RESUMO

The short-chain dehydrogenase enzymes WbmF, WbmG and WbmH from Bordetella bronchiseptica were cloned into Escherichia coli expression vectors, overexpressed and purified to homogeneity. Crystals of all three wild-type enzymes were obtained using vapour-diffusion crystallization with high-molecular-weight PEGs as a primary precipitant at alkaline pH. Some of the crystallization conditions permitted the soaking of crystals with cofactors and nucleotides or nucleotide sugars, which are possible substrate compounds, and further conditions provided co-complexes of two of the proteins with these compounds. The crystals diffracted to resolutions of between 1.50 and 2.40 A at synchrotron X-ray sources. The synchrotron data obtained were sufficient to determine eight structures of the three enzymes in complex with a variety of cofactors and substrate molecules.


Assuntos
Bordetella bronchiseptica/enzimologia , Clonagem Molecular , Regulação Enzimológica da Expressão Gênica/fisiologia , Oxirredutases/química , Oxirredutases/genética , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/química , Proteínas de Bactérias/classificação , Proteínas de Bactérias/genética , Cristalografia por Raios X , Oxirredutases/biossíntese , Oxirredutases/classificação
13.
J Agric Food Chem ; 55(12): 4704-9, 2007 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-17497875

RESUMO

High-value phytochemicals could be extracted from biomass prior to the current cellulosic pretreatment technologies (i.e., lime, ammonia, dilute acid, or pressurized hot water treatments) provided that the extraction is performed with a solvent that is compatible with the pretreatment. This work reports on the extraction of flavonoids from Albizia julibrissin biomass. While extracting A. julibrissin foliage with 50 degrees C water, 2.227 mg/g of hyperoside and 8.134 mg/g quercitrin were obtained, which is in the realm of what was obtained with 60% methanol. A. julibrissin foliage, flower, and whole plant extracts were tested in terms of their potential to inhibit low-density lipoprotein (LDL) oxidization. The highest inhibition was obtained with foliage water extracts, which were standardized at 2.5 microM of flavonoids. Also, the 2.5 microM foliage water extract resulted in a reduction from 43% to only 1% of the observed monocyte adherence. To have commercial application, A. julibrissin water extracts should be devoid of toxicity. The A. julibrissin foliage, flower, and whole plant water extracts were not toxic to Vero 76 cells. In summary, A. julibrissin biomass can be extracted with 50 degrees C water to yield an antioxidant stream, showing that it may be possible to couple extraction of valuable phytochemicals to the cellulosic pretreatment step.


Assuntos
Albizzia/química , Flavonoides/isolamento & purificação , Lipoproteínas LDL/metabolismo , Fenóis/isolamento & purificação , Extratos Vegetais/farmacologia , Animais , Chlorocebus aethiops , Flavonoides/farmacologia , Flores/química , Lipoproteínas LDL/efeitos dos fármacos , Fenóis/farmacologia , Folhas de Planta/química , Caules de Planta/química , Polifenóis , Quercetina/análogos & derivados , Quercetina/isolamento & purificação , Quercetina/farmacologia , Rutina/isolamento & purificação , Rutina/farmacologia , Células Vero , Madeira
14.
Front Public Health ; 4: 21, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26909344

RESUMO

UNLABELLED: The identification and exploration of moderators of health department accreditation remain limited by current dichotomous conceptualizations of pursuit. METHODS: A 2015 survey measured Indiana local health department (LHD) accreditation pursuit and progress, classifying respondents by progress evidence. Covariates included attitudes about the future impact of accreditation on funding and performance, health department size, geography, health outcome ranking, and quality improvement (QI) programing. RESULTS: Four classifications of accreditation pursuit emerged and were found to have greater association with covariates than standard dichotomous measures. "Active Pursuit" was associated with formal QI programing and a belief that accreditation will impact future funding and performance. "Intent Only" was associated with no QI programing and no completion of accreditation prerequisites. "Discontinued" was associated with the belief that accreditation will not impact future performance. "Not Pursuing" was associated with no interest or plan to complete prerequisites and reported belief that accreditation will not impact future health department funding or performance. CONCLUSION: More granular characterizations of accreditation pursuit may improve understanding of influential factors. This measurement framework should be validated in studies of LHDs in other states.

15.
Biochim Biophys Acta ; 1594(2): 325-34, 2002 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-11904228

RESUMO

Changes in solvent type were shown to yield significant improvement of enzyme enantioselectivity. The resolution of 3-methyl-2-butanol catalyzed by Candida antarctica lipase B, CALB, was studied in eight liquid organic solvents and supercritical carbon dioxide, SCCO(2). Studies of the temperature dependence of the enantiomeric ratio allowed determination of the enthalpic (Delta(R-S)Delta H(++)) as well as the entropic (Delta(R-S)Delta S(++)) contribution to the overall enantioselectivity (Delta(R-S)Delta G(++)= -RTlnE). A correlation of the enantiomeric ratio, E, to the van der Waals volume of the solvent molecules was observed and suggested as one of the parameters that govern solvent effects on enzyme catalysis. An enthalpy-entropy compensation relationship was indicated between the studied liquid solvents. The enzymatic mechanism must be of a somewhat different nature in SCCO(2), as this reaction in this medium did not follow the enthalpy-entropy compensation relation.


Assuntos
Candida/enzimologia , Solventes/química , Catálise , Proteínas Fúngicas , Lipase/química , Peso Molecular , Pentanóis/química , Estereoisomerismo , Temperatura , Termodinâmica
16.
Public Health Rep ; 130(5): 447-52, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26327722

RESUMO

A 2013 survey of Indiana local health departments (LHDs) measured accreditation activity and progress. Reported activities were categorized using the Public Health Accreditation Board's (PHAB's) accreditation steps as a guiding framework and matched with selected sociodemographic, organizational, and technical assistance variables. Findings indicated that 42 (59.2%) of responding Indiana LHDs reported pursuing accreditation. Of LHDs pursuing accreditation, 21 were at the initial introductory step, 18 were at the prerequisite step, one reported submitting an application to PHAB, and two reported no activity, yet intent to pursue accreditation. Reported receipt of technical assistance was associated with accreditation progress (p=0.01) and, specifically, with being at the prerequisite step. Facilitating the pursuit of LHD accreditation in states with low public health investment is possible with targeted accreditation resources. Finding meaningful measures of accreditation progress will help advance the study of factors associated with LHD accreditation on a broad scale and for the long term.


Assuntos
Acreditação/normas , Administração em Saúde Pública/normas , Acreditação/métodos , Acreditação/estatística & dados numéricos , Distribuição de Qui-Quadrado , Estudos Transversais , Indicadores Básicos de Saúde , Humanos , Indiana , Governo Local , Administração em Saúde Pública/estatística & dados numéricos , Fatores Socioeconômicos
17.
J Chromatogr A ; 954(1-2): 41-9, 2002 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-12058916

RESUMO

A new approach is presented for the determination of avoparcin in tissue. Complete recovery from spiked swine kidney was achieved with hot water modified with 30% ethanol (v/v). The samples were extracted at 75 degrees C and 50 atm by accelerated solvent extraction. In situ sample clean-up was achieved by using matrix solid-phase dispersion utilizing the acrylic polymer XAD-7 HP, and by adding triethylammonium phosphate (TEAP) to the extraction solvent. The aqueous extracts were concentrated by solid-phase extraction (SPE) on the hydrophilic interaction chromatography (HILIC) material polyhydroxyethyl aspartamide. Complete analyte retention was possible during SPE when the kidney extracts were modified with 70% ethanol. A 200 A, 5 microm HILIC column with UV225 detection was used for the separation of avoparcin. The retention time was less than 15 min with 47% aqueous component in acetonitrile and 15 mM TEAP as eluent. The average recovery of avoparcin from kidney samples was 108%.


Assuntos
Antibacterianos/análise , Cromatografia Líquida/métodos , Glicopeptídeos , Rim/química , Animais , Antibacterianos/isolamento & purificação , Espectrofotometria Ultravioleta , Suínos
18.
J Agric Food Chem ; 50(24): 7111-3, 2002 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-12428968

RESUMO

A mathematical model was developed to describe the reduction of soybean oil triglycerides during hydrogenation. The model was derived from reaction and transport mechanisms and formulated into a system of first-order irreversible rate expressions that included terms for temperature, hydrogen pressure, and catalyst concentration. The model parameters were estimated from experimental data, and the model was used to simulate the results of hydrogenation performed over the pressure range of 0.069-6.9 MPa. The model could be extended to include geometrical isomers formed during hydrogenation.


Assuntos
Hidrogênio/química , Modelos Químicos , Óleo de Soja/química , Triglicerídeos/química , Hidrogenação , Cinética , Matemática , Níquel/química , Oxirredução , Pressão , Temperatura , Triglicerídeos/análise
19.
J AOAC Int ; 87(4): 797-810, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15295872

RESUMO

The use of enzymes coupled with supercritical fluid (SF)-based analytical techniques, such as supercritical fluid extraction (SFE), provides a safer environment platform for the analytical chemist and reduces the use of organic solvents. Incorporation of such techniques not only reduces the use of solvent in analytical laboratories, but it can also lead to overall method simplification and time savings. In this review, some of the fundamental aspects of using enzymes in the presence of SF media are discussed, particularly the influence of extraction (reaction) pressure, temperature, and water content of the extracting fluid and/or the sample matrix. Screening of optimal conditions for conducting reactions in the presence of SF media can be readily accomplished with automated serial or parallel SFE instrumentation, including selection of the proper enzyme. Numerous examples are cited, many based on lipase-initiated conversions of lipid substrates, to form useful analytical derivatives for gas chromatography, liquid chromatography, or SF chromatography analysis. In certain cases, enzymatic-aided processing of samples can permit the coupling of the extraction, sample preparation, and final analysis steps. The derived methods/techniques find application in nutritional food analyses, assays of industrial products, and micro analyses of specific samples.


Assuntos
Técnicas de Química Analítica/métodos , Enzimas/química , Animais , Cromatografia com Fluido Supercrítico , Enzimas Imobilizadas , Humanos , Lipase/química
20.
Annu Rev Food Sci Technol ; 5: 215-38, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24328430

RESUMO

This review provides an update on the use of supercritical fluid (SCF) technology as applied to food-based materials. It advocates the use of the solubility parameter theory (SPT) for rationalizing the results obtained when employing sub- and supercritical media to food and nutrient-bearing materials and for optimizing processing conditions. Total extraction and fractionation of foodstuffs employing SCFs are compared and are illustrated by using multiple fluids and unit processes to obtain the desired food product. Some of the additional prophylactic benefits of using carbon dioxide as the processing fluid are explained and illustrated with multiple examples of commercial products produced using SCF media. I emphasize the role of SCF technology in the context of environmentally benign and sustainable processing, as well as its integration into an overall biorefinery concept. Conclusions are drawn in terms of current trends in the field and future research that is needed to secure new applications of the SCF platform as applied in food science and technology.


Assuntos
Cromatografia com Fluido Supercrítico , Tecnologia de Alimentos/métodos , Alimentos , Antioxidantes/isolamento & purificação , Dióxido de Carbono , Cromatografia com Fluido Supercrítico/métodos , Suplementos Nutricionais , Manipulação de Alimentos/métodos , Microbiologia de Alimentos , Tecnologia de Alimentos/tendências , Humanos , Pasteurização , Pressão , Solubilidade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA