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1.
Alzheimers Dement ; 20(2): 986-994, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37837524

RESUMO

INTRODUCTION: Depressive symptoms are among early behavioral changes in Alzheimer's disease (AD); however, the relationship between neurodegeneration and depressive symptoms remains inconclusive. To better understand this relationship in preclinical AD, we examined hippocampal volume and depressive symptoms in cognitively unimpaired carriers of the presenilin-1 (PSEN1) E280A mutation for autosomal dominant AD. METHODS: A total of 27 PSEN1 mutation carriers and 26 non-carrier family members were included. Linear regression was used to test the relationship between hippocampal volume and 15-item Geriatric Depression Scale. RESULTS: Carriers and non-carriers did not differ in depressive symptoms or hippocampal volume. Within carriers, lower hippocampal volume was associated with greater depressive symptoms, which remained significant after adjusting for age and cognition. This relationship was not significant in non-carriers. DISCUSSION: Hippocampal neurodegeneration may underlie depressive symptoms in preclinical autosomal dominant AD. These findings provide support for the utility of targeting depressive symptoms in AD prevention. HIGHLIGHTS: We compared unimpaired autosomal dominant Alzheimer's disease (AD) mutation carriers and non-carriers. Carriers and non-carriers did not differ in severity of depressive symptoms. In carriers, hippocampal volume was inversely associated with depressive symptoms. Depressive symptoms may be a useful target in AD prevention.


Assuntos
Doença de Alzheimer , Humanos , Idoso , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/genética , Doença de Alzheimer/complicações , Depressão/genética , Mutação/genética , Hipocampo/diagnóstico por imagem , Presenilina-1/genética , Cognição
2.
Alzheimers Dement ; 19(1): 169-180, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-35298083

RESUMO

INTRODUCTION: Autopsy studies recognize the locus coeruleus (LC) as one of the first sites accumulating tau in Alzheimer's disease (AD). Recent AD work related in vivo LC magnetic resonance imaging (MRI) integrity to tau and cognitive decline; however, relationships of LC integrity to age, tau, and cognition in autosomal dominant AD (ADAD) remain unexplored. METHODS: We associated LC integrity (3T-MRI) with estimated years of onset, cortical amyloid beta, regional tau (positron emission tomography [PET]) and memory (Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word-List-Learning) among 27 carriers and 27 non-carriers of the presenilin-1 (PSEN1) E280A mutation. Longitudinal changes between LC integrity and tau were evaluated in 10 carriers. RESULTS: LC integrity started to decline at age 32 in carriers, 12 years before clinical onset, and 20 years earlier than in sporadic AD. LC integrity was negatively associated with cortical tau, independent of amyloid beta, and predicted precuneus tau increases. LC integrity was positively associated with memory. DISCUSSION: These findings support LC integrity as marker of disease progression in preclinical ADAD.


Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Adulto , Humanos , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/genética , Peptídeos beta-Amiloides/metabolismo , Locus Cerúleo , Mutação/genética , Tomografia por Emissão de Pósitrons/métodos , Presenilina-1/genética , Proteínas tau/genética , Proteínas tau/metabolismo
3.
PLoS Pathog ; 15(8): e1007652, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31404118

RESUMO

Enterohemorrhagic Escherichia coli O157:H7 (EHEC) is an important food-borne pathogen that colonizes the colon. Transposon-insertion sequencing (TIS) was used to identify genes required for EHEC and E. coli K-12 growth in vitro and for EHEC growth in vivo in the infant rabbit colon. Surprisingly, many conserved loci contribute to EHEC's but not to K-12's growth in vitro. There was a restrictive bottleneck for EHEC colonization of the rabbit colon, which complicated identification of EHEC genes facilitating growth in vivo. Both a refined version of an existing analytic framework as well as PCA-based analysis were used to compensate for the effects of the infection bottleneck. These analyses confirmed that the EHEC LEE-encoded type III secretion apparatus is required for growth in vivo and revealed that only a few effectors are critical for in vivo fitness. Over 200 mutants not previously associated with EHEC survival/growth in vivo also appeared attenuated in vivo, and a subset of these putative in vivo fitness factors were validated. Some were found to contribute to efficient type-three secretion while others, including tatABC, oxyR, envC, acrAB, and cvpA, promote EHEC resistance to host-derived stresses. cvpA is also required for intestinal growth of several other enteric pathogens, and proved to be required for EHEC, Vibrio cholerae and Vibrio parahaemolyticus resistance to the bile salt deoxycholate, highlighting the important role of this previously uncharacterized protein in pathogen survival. Collectively, our findings provide a comprehensive framework for understanding EHEC growth in the intestine.


Assuntos
Elementos de DNA Transponíveis , Infecções por Escherichia coli/microbiologia , Escherichia coli O157/crescimento & desenvolvimento , Proteínas de Escherichia coli/metabolismo , Intestinos/microbiologia , Fatores de Virulência/metabolismo , Animais , Infecções por Escherichia coli/genética , Infecções por Escherichia coli/metabolismo , Escherichia coli O157/genética , Escherichia coli O157/isolamento & purificação , Proteínas de Escherichia coli/genética , Regulação Bacteriana da Expressão Gênica , Coelhos , Análise de Sequência de DNA , Fatores de Virulência/genética
4.
Nat Chem Biol ; 12(4): 268-274, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26900865

RESUMO

Activity-based protein profiling (ABPP) is a chemoproteomic tool for detecting active enzymes in complex biological systems. We used ABPP to identify secreted bacterial and host serine hydrolases that are active in animals infected with the cholera pathogen Vibrio cholerae. Four V. cholerae proteases were consistently active in infected rabbits, and one, VC0157 (renamed IvaP), was also active in human choleric stool. Inactivation of IvaP influenced the activity of other secreted V. cholerae and rabbit enzymes in vivo, and genetic disruption of all four proteases increased the abundance of intelectin, an intestinal lectin, and its binding to V. cholerae in infected rabbits. Intelectin also bound to other enteric bacterial pathogens, suggesting that it may constitute a previously unrecognized mechanism of bacterial surveillance in the intestine that is inhibited by pathogen-secreted proteases. Our work demonstrates the power of activity-based proteomics to reveal host-pathogen enzymatic dialog in an animal model of infection.


Assuntos
Interações Hospedeiro-Patógeno/fisiologia , Intestinos , Lectinas/metabolismo , Peptídeo Hidrolases/metabolismo , Proteômica/métodos , Vibrio cholerae/enzimologia , Animais , Cólera/enzimologia , Cólera/microbiologia , Modelos Animais de Doenças , Fezes/enzimologia , Humanos , Intestinos/enzimologia , Intestinos/microbiologia , Proteólise , Coelhos , Serina Endopeptidases/metabolismo
5.
Nature ; 492(7427): 113-7, 2012 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-23160491

RESUMO

The mammalian gastrointestinal tract provides a complex and competitive environment for the microbiota. Successful colonization by pathogens requires scavenging nutrients, sensing chemical signals, competing with the resident bacteria and precisely regulating the expression of virulence genes. The gastrointestinal pathogen enterohaemorrhagic Escherichia coli (EHEC) relies on inter-kingdom chemical sensing systems to regulate virulence gene expression. Here we show that these systems control the expression of a novel two-component signal transduction system, named FusKR, where FusK is the histidine sensor kinase and FusR the response regulator. FusK senses fucose and controls expression of virulence and metabolic genes. This fucose-sensing system is required for robust EHEC colonization of the mammalian intestine. Fucose is highly abundant in the intestine. Bacteroides thetaiotaomicron produces multiple fucosidases that cleave fucose from host glycans, resulting in high fucose availability in the gut lumen. During growth in mucin, B. thetaiotaomicron contributes to EHEC virulence by cleaving fucose from mucin, thereby activating the FusKR signalling cascade, modulating the virulence gene expression of EHEC. Our findings suggest that EHEC uses fucose, a host-derived signal made available by the microbiota, to modulate EHEC pathogenicity and metabolism.


Assuntos
Proteínas de Bactérias/metabolismo , Bacteroides/metabolismo , Escherichia coli Êntero-Hemorrágica/crescimento & desenvolvimento , Fucose/metabolismo , Trato Gastrointestinal/microbiologia , Animais , Bacteroides/enzimologia , Bacteroides/crescimento & desenvolvimento , Escherichia coli Êntero-Hemorrágica/genética , Escherichia coli Êntero-Hemorrágica/patogenicidade , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Trato Gastrointestinal/metabolismo , Regulação Bacteriana da Expressão Gênica , Mucinas/metabolismo , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Coelhos , Receptores Adrenérgicos/metabolismo , Transdução de Sinais , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Virulência/genética , Fatores de Virulência/genética , alfa-L-Fucosidase/metabolismo
6.
J Appl Gerontol ; : 7334648241271975, 2024 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-39229852

RESUMO

Objectives: Examine whether physical activity (PA) changes during the COVID-19 pandemic were related to subjective cognitive decline (SCD), depression, and anxiety in older adults and whether these varied by sociodemographic variables. Methods: 301 older adults completed an online survey between May and October 2020 and 3 months later, including self-report questionnaires of SCD, depression, and anxiety. PA changes were determined with a question. Results: 60% of participants reported decreased PA. Those who reduced their PA were more likely to be from low to middle income and younger. PA increase was related to less SCD and depressive symptoms compared to those who decreased it. Participants who maintained their PA had fewer SCD concerns, depressive, and anxiety symptoms than those who decreased it. Discussion: Reducing PA was associated with worse neuropsychiatric and cognitive symptoms. Encouraging older adults to increase PA may help mitigate some of the pandemic's adverse effects on psychological well-being.

8.
Biochem J ; 445(3): 383-92, 2012 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-22587461

RESUMO

EPEC (enteropathogenic Escherichia coli) and EHEC (enterohaemorrhagic Escherichia coli) are attaching and effacing pathogens frequently associated with infectious diarrhoea. EPEC and EHEC use a T3SS (type III secretion system) to translocate effectors that subvert different cellular processes to sustain colonization and multiplication. The eukaryotic proteins NHERF2 (Na(+)/H(+) exchanger regulatory factor 2) and AnxA2 (annexin A2), which are involved in regulation of intestinal ion channels, are recruited to the bacterial attachment sites. Using a stable HeLa-NHERF2 cell line, we found partial co-localization of AnxA2 and NHERF2; in EPEC-infected cells, AnxA2 and NHERF2 were extensively recruited to the site of bacterial attachment. We confirmed that NHERF2 dimerizes and found that NHERF2 interacts with AnxA2. Moreover, we found that AnxA2 also binds both the N- and C-terminal domains of the bacterial effector Tir through its C-terminal domain. Immunofluorescence of HeLa cells infected with EPEC showed that AnxA2 is recruited to the site of bacterial attachment in a Tir-dependent manner, but independently of Tir-induced actin polymerization. Our results suggest that AnxA2 and NHERF2 form a scaffold complex that links adjacent Tir molecules at the plasma membrane forming a lattice that could be involved in retention and dissemination of other effectors at the bacterial attachment site.


Assuntos
Anexina A2/fisiologia , Aderência Bacteriana/fisiologia , Escherichia coli Êntero-Hemorrágica/fisiologia , Escherichia coli Êntero-Hemorrágica/patogenicidade , Escherichia coli Enteropatogênica/fisiologia , Escherichia coli Enteropatogênica/patogenicidade , Interações Hospedeiro-Patógeno/fisiologia , Fosfoproteínas/fisiologia , Trocadores de Sódio-Hidrogênio/fisiologia , Anexina A2/genética , Aderência Bacteriana/genética , Sequência de Bases , Primers do DNA/genética , Diarreia/microbiologia , Diarreia/fisiopatologia , Escherichia coli Êntero-Hemorrágica/genética , Escherichia coli Enteropatogênica/genética , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/fisiopatologia , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/fisiologia , Células HeLa , Interações Hospedeiro-Patógeno/genética , Humanos , Modelos Biológicos , Fosfoproteínas/química , Fosfoproteínas/genética , Domínios e Motivos de Interação entre Proteínas , Receptores de Superfície Celular/química , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/fisiologia , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Trocadores de Sódio-Hidrogênio/química , Trocadores de Sódio-Hidrogênio/genética
9.
J Appl Gerontol ; 42(3): 376-386, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36396599

RESUMO

Subjective cognitive decline (SCD), which precedes Mild Cognitive Impairment and dementia, may be affected by purpose in life (PiL) and loneliness in older adults. We investigated associations among PiL, loneliness, and SCD in US Latino (n = 126), Black (n = 74), Asian (n = 33), and White (n = 637) adults. Higher PiL predicted lower SCD in all groups (p-values < .012), except Black participants. Lower loneliness predicted lower SCD in Latino and White groups (p-values < .05), and PiL moderated this association in White adults. PiL and loneliness may play important roles in cognitive decline. Differential predictors of SCD suggest differential targets for preventing cognitive decline and dementia across ethnoracial groups.


Assuntos
Disfunção Cognitiva , Demência , Solidão , Idoso , Humanos , Disfunção Cognitiva/epidemiologia , Disfunção Cognitiva/psicologia , Demência/epidemiologia , Solidão/psicologia , Estados Unidos/epidemiologia
10.
Mol Microbiol ; 80(6): 1420-38, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21488979

RESUMO

The human pathogens enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC) share a unique mechanism of colonization that results from the concerted action of effector proteins translocated into the host cell by a type III secretion system (T3SS). EPEC and EHEC not only induce characteristic attaching and effacing (A/E) lesions, but also subvert multiple host cell signalling pathways during infection. Our understanding of the mechanisms by which A/E pathogens hijack host cell signalling has advanced dramatically in recent months with the identification of novel activities for many effectors. In addition to further characterization of established effectors (Tir, EspH and Map), new effectors have emerged as important mediators of virulence through activities such as mimicry of Rho guanine nucleotide exchange factors (Map and EspM), inhibition of apoptosis (NleH and NleD), interference with inflammatory signalling pathways (NleB, NleC, NleE and NleH) and phagocytosis (EspF, EspH and EspJ). The findings have highlighted the multifunctional nature of the effectors and their ability to participate in redundant, synergistic or antagonistic relationships, acting in a co-ordinated spatial and temporal manner on different host organelles and cellular pathways during infection.


Assuntos
Escherichia coli Êntero-Hemorrágica/metabolismo , Escherichia coli Enteropatogênica/metabolismo , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/metabolismo , Animais , Escherichia coli Êntero-Hemorrágica/genética , Escherichia coli Êntero-Hemorrágica/patogenicidade , Escherichia coli Enteropatogênica/genética , Escherichia coli Enteropatogênica/patogenicidade , Infecções por Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Humanos , Transdução de Sinais
11.
EClinicalMedicine ; 35: 100848, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33997742

RESUMO

BACKGROUND: In the COVID-19 pandemic, older adults from vulnerable ethnoracial groups are at high risk of infection, hospitalization, and death. We aimed to explore the pandemic's impact on the well-being and cognition of older adults living in the United States (US), Argentina, Chile, Mexico, and Peru. METHODS: 1,608 (646 White, 852 Latino, 77 Black, 33 Asian; 72% female) individuals from the US and four Latin American countries aged ≥ 55 years completed an online survey regarding well-being and cognition during the pandemic between May and September 2020. Outcome variables (pandemic impact, discrimination, loneliness, purpose of life, subjective cognitive concerns) were compared across four US ethnoracial groups and older adults living in Argentina, Chile, Mexico, and Peru. FINDINGS: Mean age for all participants was 66.7 (SD = 7.7) years and mean education was 15.4 (SD = 2.7) years. Compared to Whites, Latinos living in the US reported greater economic impact (p < .001, ηp 2  = 0.031); while Blacks reported experiencing discrimination more often (p < .001, ηp 2  = 0.050). Blacks and Latinos reported more positive coping (p < .001, ηp 2  = 0.040). Compared to Latinos living in the US, Latinos in Chile, Mexico, and Peru reported greater pandemic impact, Latinos in Mexico and Peru reported more positive coping, Latinos in Argentina, Mexico, and Peru had greater economic impact, and Latinos in Argentina, Chile, and Peru reported less discrimination. INTERPRETATION: The COVID-19 pandemic has differentially impacted the well-being of older ethnically diverse individuals in the US and Latin America. Future studies should examine how mediators like income and coping skills modify the pandemic's impact. FUNDING: Massachusetts General Hospital Department of Psychiatry.

12.
J Bacteriol ; 192(13): 3534-9, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20400543

RESUMO

We report that the N terminus of the type III secretion system translocator proteins EspB, EspD, and EspA mediate protein secretion and translocation from wild-type enteropathogenic Escherichia coli and hypersecretion from sepL and sepD mutants. EspA containing the translocation signal of Map and Tir containing the secretion signal of EspA are biologically active.


Assuntos
Escherichia coli Enteropatogênica/metabolismo , Proteínas de Escherichia coli/metabolismo , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/metabolismo , Escherichia coli Enteropatogênica/genética , Proteínas de Escherichia coli/genética , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo
13.
J Bacteriol ; 192(22): 6093-8, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20833800

RESUMO

Here we show that the type III secretion gatekeeper protein SepL resembles an aberrant effector protein in binding to a class 1 type III secretion chaperone (Orf12, here renamed CesL). We also show that short N-terminal fragments (≤70 amino acids) from SepL are capable of targeting fusion proteins for secretion and translocation.


Assuntos
Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , Chaperonas Moleculares/metabolismo , Sequência de Aminoácidos , Proteínas de Escherichia coli/genética , Dados de Sequência Molecular , Ligação Proteica , Sinais Direcionadores de Proteínas , Transporte Proteico , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos
14.
Mol Microbiol ; 69(4): 911-25, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18627459

RESUMO

Type 1 fimbriae are assembled by the chaperone-usher pathway where periplasmic protein complexes formed between fimbrial subunits and the FimC chaperone are recruited by the outer membrane protein FimD (the usher) for their ordered polymerization and export. FimH adhesin initiates and stimulates type 1 fimbriae polymerization by interacting with FimD. Previously we showed that the N-terminal lectin domain of FimH (N-FimH) is necessary for binding of the adhesin to FimD. In this work, we have selected mutants in N-FimH that reduce the levels of adhesin and type 1 fimbriae displayed in Escherichia coli without altering the levels of FimH in the periplasm. The selected mutations are mostly concentrated in residues G15, N46 and D47. In contrast to other mutations isolated that simply affect binding of FimH to FimD (e.g. C3Y), these variants associate to FimD and alter its susceptibility to trypsin digestion similarly to wild-type FimH. Importantly, their mutant phenotype is rescued when FimD is activated in vivo by the coexpression of wild-type FimH. Altogether, these data indicate that residues G15, N46 and D47 play an important role following initial binding of FimH to FimD for efficient type 1 fimbriae polymerization by this outer membrane usher.


Assuntos
Adesinas de Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , Proteínas de Fímbrias/metabolismo , Fímbrias Bacterianas/metabolismo , Adesinas de Escherichia coli/genética , Sequência de Aminoácidos , Aminoácidos/genética , Aminoácidos/metabolismo , Escherichia coli/ultraestrutura , Proteínas de Fímbrias/genética , Fímbrias Bacterianas/genética , Fímbrias Bacterianas/ultraestrutura , Microscopia Eletrônica de Transmissão , Dados de Sequência Molecular , Mutação Puntual , Estrutura Terciária de Proteína/genética , Tripsina/química
15.
Nat Commun ; 6: 7438, 2015 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-26074426

RESUMO

Beyond its role in host defense, bacterial DNA methylation also plays important roles in the regulation of gene expression, virulence and antibiotic resistance. Bacterial cells in a clonal population can generate epigenetic heterogeneity to increase population-level phenotypic plasticity. Single molecule, real-time (SMRT) sequencing enables the detection of N6-methyladenine and N4-methylcytosine, two major types of DNA modifications comprising the bacterial methylome. However, existing SMRT sequencing-based methods for studying bacterial methylomes rely on a population-level consensus that lacks the single-cell resolution required to observe epigenetic heterogeneity. Here, we present SMALR (single-molecule modification analysis of long reads), a novel framework for single molecule-level detection and phasing of DNA methylation. Using seven bacterial strains, we show that SMALR yields significantly improved resolution and reveals distinct types of epigenetic heterogeneity. SMALR is a powerful new tool that enables de novo detection of epigenetic heterogeneity and empowers investigation of its functions in bacterial populations.


Assuntos
Metilação de DNA , DNA Bacteriano/metabolismo , Epigênese Genética , Sequência de Bases , Campylobacter jejuni/genética , Caulobacter crescentus/genética , Chromohalobacter/genética , Metilases de Modificação do DNA/genética , Metilases de Modificação do DNA/metabolismo , Escherichia coli/genética , Genoma Bacteriano , Geobacter/genética , Helicobacter pylori/genética , Dados de Sequência Molecular , Análise de Sequência de DNA
16.
Nat Commun ; 5: 3080, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24445323

RESUMO

The outbreak of diarrhoea and haemolytic uraemic syndrome that occurred in Germany in 2011 was caused by a Shiga toxin-producing enteroaggregative Escherichia coli (EAEC) strain. The strain was classified as EAEC owing to the presence of a plasmid (pAA) that mediates a characteristic pattern of aggregative adherence on cultured cells, the defining feature of EAEC that has classically been associated with virulence. Here we describe an infant rabbit-based model of intestinal colonization and diarrhoea caused by the outbreak strain, which we use to decipher the factors that mediate the pathogen's virulence. Shiga toxin is the key factor required for diarrhoea. Unexpectedly, we observe that pAA is dispensable for intestinal colonization and development of intestinal pathology. Instead, chromosome-encoded autotransporters are critical for robust colonization and diarrhoeal disease in this model. Our findings suggest that conventional wisdom linking aggregative adherence to EAEC intestinal colonization is false for at least a subset of strains.


Assuntos
Proteínas de Transporte/fisiologia , Proteínas de Escherichia coli/fisiologia , Plasmídeos/fisiologia , Escherichia coli Shiga Toxigênica/genética , Escherichia coli Shiga Toxigênica/patogenicidade , Animais , Diarreia/metabolismo , Diarreia/microbiologia , Diarreia/fisiopatologia , Modelos Animais de Doenças , Infecções por Escherichia coli/metabolismo , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/fisiopatologia , Feminino , Intestinos/microbiologia , Intestinos/patologia , Masculino , Filogenia , Coelhos
17.
mBio ; 5(2): e00974-14, 2014 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-24667709

RESUMO

Many pathogens produce the ß-(1-6)-linked poly-N-acetylglucosamine (PNAG) surface polysaccharide that is being developed as a broadly protective antimicrobial vaccine. However, it is unknown whether systemically injected PNAG vaccines or antibodies would provide protective immunity against pathogens confined to the gastrointestinal tract such as Shiga toxin (Stx)-producing Escherichia coli (STEC), an important group of gastrointestinal (GI) pathogens for which effective immunotherapeutics are lacking. To ascertain whether systemic IgG antibody to PNAG impacts this infectious situation, a vaccine consisting of a synthetic nonamer of nonacetylated PNAG, 9GlcNH2, conjugated to the Shiga toxin 1b subunit (9GlcNH2-Stx1b) was produced. Rabbit antibodies raised to the conjugate vaccine were tested for bacterial killing and toxin neutralization in vitro and protection against infection in infant mice. Cell surface PNAG was detected on all 9 STEC isolates tested, representing 6 STEC serogroups, including E. coli O157:H7. Antibody to the 9GlcNH2-Stx1b conjugate neutralized Stx1 potently and Stx2 modestly. For O157:H7 and O104:H4 STEC strains, antibodies elicited by the 9GlcNH2-Stx1b conjugate possessed opsonic killing and bactericidal activity. Following intraperitoneal injection, antibodies to both PNAG and Stx were needed for infant mouse protection against O157 STEC. These antibodies also mediated protection against the Stx2-producing O104:H4 strain that was the cause of a recent outbreak in Germany, although sufficient doses of antibody to PNAG alone were protective against this strain in infant mice. Our observations suggest that vaccination against both PNAG and Stx, using a construct such as the 9GlcNH2-Stx1b conjugate vaccine, would be protective against a broad range of STEC serogroups. IMPORTANCE The presence of poly-N-acetylglucosamine (PNAG) on many pathogens presents an opportunity to target this one structure with a multispecies vaccine. Whether antibodies to PNAG can protect against pathogens confined to the gastrointestinal tract is not known. As Shiga toxin (Stx)-producing Escherichia coli (STEC) bacteria are serious causes of infection whose virulence is dependent on elaboration of Stx, we prepared a vaccine containing a synthetic nonamer of PNAG (9GlcNH2) conjugated to Shiga toxin 1b subunit (9GlcNH2-Stx1b) to evaluate bacterial killing, toxin neutralization, and protective efficacy in infant mice. All nine (100%) clinical strains of STEC from different serogroups expressed PNAG. Vaccine-induced antibody mediated in vitro killing of STEC and neutralization of both Stx1 and Stx2. Passive administration of antibody to the conjugate showed protection requiring immunity to both PNAG and Stx for O157 strains, although for an O104 strain, antibody to PNAG alone was protective. Immunity to PNAG may contribute to protection against STEC infections.


Assuntos
Infecções por Escherichia coli/prevenção & controle , Vacinas contra Escherichia coli/imunologia , Toxina Shiga/imunologia , Escherichia coli Shiga Toxigênica/imunologia , beta-Glucanas/imunologia , Animais , Animais Recém-Nascidos , Anticorpos Antibacterianos/sangue , Anticorpos Neutralizantes/sangue , Antitoxinas/sangue , Modelos Animais de Doenças , Infecções por Escherichia coli/imunologia , Vacinas contra Escherichia coli/administração & dosagem , Camundongos , Viabilidade Microbiana/imunologia , Proteínas Opsonizantes/sangue , Coelhos , Vacinas Conjugadas/administração & dosagem , Vacinas Conjugadas/imunologia
18.
Nat Commun ; 5: 5887, 2014 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-25523213

RESUMO

The hallmark of enteropathogenic Escherichia coli (EPEC) infection is the formation of actin-rich pedestal-like structures, which are generated following phosphorylation of the bacterial effector Tir by cellular Src and Abl family tyrosine kinases. This leads to recruitment of the Nck-WIP-N-WASP complex that triggers Arp2/3-dependent actin polymerization in the host cell. The same phosphorylation-mediated signalling network is also assembled downstream of the Vaccinia virus protein A36 and the phagocytic Fc-gamma receptor FcγRIIa. Here we report that the EPEC type-III secretion system effector EspJ inhibits autophosphorylation of Src and phosphorylation of the Src substrates Tir and FcγRIIa. Consistent with this, EspJ inhibits actin polymerization downstream of EPEC, Vaccinia virus and opsonized red blood cells. We identify EspJ as a unique adenosine diphosphate (ADP) ribosyltransferase that directly inhibits Src kinase by simultaneous amidation and ADP ribosylation of the conserved kinase-domain residue, Src E310, resulting in glutamine-ADP ribose.


Assuntos
Difosfato de Adenosina/metabolismo , Escherichia coli Êntero-Hemorrágica/metabolismo , Infecções por Escherichia coli/enzimologia , Proteínas de Escherichia coli/metabolismo , Quinases da Família src/metabolismo , Difosfato de Adenosina/genética , Motivos de Aminoácidos , Escherichia coli Êntero-Hemorrágica/genética , Infecções por Escherichia coli/genética , Infecções por Escherichia coli/metabolismo , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/genética , Humanos , Fosforilação , Processamento de Proteína Pós-Traducional , Receptores de IgG/metabolismo , Quinases da Família src/química , Quinases da Família src/genética
19.
Nat Biotechnol ; 30(12): 1232-9, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23138224

RESUMO

Single-molecule real-time (SMRT) DNA sequencing allows the systematic detection of chemical modifications such as methylation but has not previously been applied on a genome-wide scale. We used this approach to detect 49,311 putative 6-methyladenine (m6A) residues and 1,407 putative 5-methylcytosine (m5C) residues in the genome of a pathogenic Escherichia coli strain. We obtained strand-specific information for methylation sites and a quantitative assessment of the frequency of methylation at each modified position. We deduced the sequence motifs recognized by the methyltransferase enzymes present in this strain without prior knowledge of their specificity. Furthermore, we found that deletion of a phage-encoded methyltransferase-endonuclease (restriction-modification; RM) system induced global transcriptional changes and led to gene amplification, suggesting that the role of RM systems extends beyond protecting host genomes from foreign DNA.


Assuntos
Escherichia coli/genética , 5-Metilcitosina/metabolismo , Adenina/análogos & derivados , Adenina/metabolismo , Biotecnologia , Mapeamento Cromossômico , Metilação de DNA/genética , Enzimas de Restrição-Modificação do DNA/deficiência , Enzimas de Restrição-Modificação do DNA/genética , Enzimas de Restrição-Modificação do DNA/metabolismo , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Bacteriano/metabolismo , Escherichia coli/metabolismo , Escherichia coli/patogenicidade , Amplificação de Genes , Deleção de Genes , Genoma Bacteriano , Análise de Sequência de DNA/métodos , Compostos de Espiro , Especificidade por Substrato
20.
Investig. enferm ; 15(2): 1-21, 2013.
Artigo em Espanhol | LILACS, BDENF, COLNAL | ID: biblio-1119654

RESUMO

La investigación de la cual surge este artículo tuvo como objetivo comprender e interpretar la percepción de un grupo de profesionales de enfermería sobre su experiencia educativa en el ámbito clínico. La educación es un componente central del cuidado en este campo y, por lo tanto, debe ser objeto de investigación para potenciarse o mejorarse. Se desarrolló un estudio cualitativo con enfoque fenomenológico. Previo consentimiento informado se realizó una entrevista semiestructurada a catorce profesionales de enfermería de diferentes hospitales de Medellín, Colombia, elegidos de manera intencionada hasta obtener saturación teórica. Las entrevistas se grabaron, transcribieron y analizaron con base en los parámetros establecidos para estos estudios. A partir del análisis de los resultados emergieron las siguientes categorías: de la información a la transformación; para el cuidado y autocuidado; en todo momento y en todo lugar; el compromiso es con todos; la carga laboral como obstáculo; lo personal también influye, y educación: actividad puntual o proceso. La investigación permitió concluir que la experiencia educativa del profesional es significativa en la medida en que cuanto hace parte sustancial de su rol de gestor y cuidador; es amplia en términos de beneficiarios y permanente en el tiempo y tiene como fin favorecer el cuidado y autocuidado en los ámbitos hospitalario y domiciliario. No obstante, esta labor es limitada y se compone de actividades que, frecuentemente, tienen un carácter prescriptivo y puntual. Se requiere avanzar en la aplicación de modelos educativos clínicos dialógicos que se desarrollen con un enfoque de proceso.


The research from which this article arises aimed at understanding and interpreting the perception of a group of nurses about their educational experience in the clinical setting. Education is a central component of care in this field and, therefore, should be investigated to be enhanced or improved. The research approach was a qualitative phenomenological study which was carried out with fourteen nurses from different hospitals in Medellin, Colombia, intentionally chosen until reaching theoretical saturation. After giving an Informed consent to the participants, they were part of a semi-structured interview. The interviews were recorded, transcribed and analyzed based on the parameters established for this type of study. From the analysis of the results the following categories emerged: information processing; care and self-care, at all times and in all places, the commitment is to all, the workload as a barrier, personal stuff also affects, and education: specific activity or process. The investigation concluded that the professional educational experience is significant to the extent that the education the professional provides plays a substantial part of its role as manager and caretaker, it is broad in terms of beneficiaries and permanent in time and it is designed to favor the care and self-care in hospital and home settings. However, this work is limited and consists of activities that frequently have a prescriptive and timely character. It requires progress in implementing clinical education dialogic models that are developed with a process approach.


A pesquisa da qual o presente artigo surge, teve como objetivo compreender e interpretar a percepção de um grupo de profissionais de enfermagem no que diz respeito da sua experiência educacional no âmbito clínico. A educação resulta ser um componente central do cuidado neste campo e, por tanto, deve ser objeto de pesquisa para se potenciar ou melhorar. Foi desenvolvido um estudo qualitativo com enfoque fenomenológico. Após consentimento informado aplicou-se entrevista semiestruturada em quatorze profissionais de enfermagem de diferentes hospitais de Medellín, Colômbia, elegidos de maneira intencionada até obter saturação teórica. As entrevistas foram gravadas, transcritas e analisadas com base nos parâmetros estabelecidos para este tipo de estudos. A partir da análise dos resultados emergiram as seguintes categorias: da informação para a transformação; para o cuidado e autocuidado; em todos os momentos e em todos os lugares; o compromisso vai com todo mundo; a carga laboral como barreira; o pessoal influi mesmo, e educação: atividade pontual ou processo. A pesquisa permitiu concluir que a experiência educativa do profissional é significativa na medida em que o ensino que brinda faz parte substancial do seu papel de gestor e atendente; é ampla em termos de beneficiários, permanente no tempo e tem como objetivo favorecer o cuidado e autocuidado nos âmbitos hospitalar e domiciliário. No entanto, este trabalho é limitado e compõe-se de atividades que, frequentemente, tem caráter prescritivo e pontual. Precisa avançar na aplicação de modelos educativos clínicos dialógicos desenvoltos com enfoque de processo.


Assuntos
Humanos , Educação , Pesquisa , Enfermeiras e Enfermeiros
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