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1.
Front Psychol ; 15: 1357939, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38596330

RESUMO

Introduction: Students need to acquire high level self-regulatory skills if they are to be successful within higher education, and academics need support in facilitating this. In this article we explore how the current research gap between knowledge of self-regulatory assessment and feedback (SRAF) practices, and academics' professional training in it can be bridged. Methods: SRAF tools were used with academics to explore their understandings of and training needs in SRAF; central to this work was the development of a SRAF scale. We consider the value of such tools in supporting academics' professional development needs in SRAF. The reliability and validity of the SRAF scale was tested using exploratory factor analyses (EFA). Results: Iterative EFA resulted in a 17 item support required SRAF scale (SR). Two underpinning factors: Creating the Conditions for SRAF, and Supporting Students' SRAF Skills Development were identified. The reliability of the instrument supported its primary use as a tool to facilitate academics' professional development in fostering students' self-regulatory skills. Discussion: Our findings highlight the importance of supporting academics in developing strategies to maximize students' metacognitive skills and motivation in assessment and feedback, contingent on effective assessment design. Such professional development needs to be mindful of individual and contextual factors impacting academics' access to, and confidence and competence in, using SRAF in practice. This research is important in highlighting potential disconnects between where academics' focus their attention in assessment, and what is known to have most impact on student learning success. The SRAF tools have considerable potential in supporting translation of theory into practice as part of sustained professional development for academics in higher education.

2.
Eur Heart J ; 44(34): 3278-3291, 2023 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-37592821

RESUMO

BACKGROUND AND AIMS: For patients with congenitally corrected transposition of the great arteries (ccTGA), factors associated with progression to end-stage congestive heart failure (CHF) remain largely unclear. METHODS: This multicentre, retrospective cohort study included adults with ccTGA seen at a congenital heart disease centre. Clinical data from initial and most recent visits were obtained. The composite primary outcome was mechanical circulatory support, heart transplantation, or death. RESULTS: From 558 patients (48% female, age at first visit 36 ± 14.2 years, median follow-up 8.7 years), the event rate of the primary outcome was 15.4 per 1000 person-years (11 mechanical circulatory support implantations, 12 transplantations, and 52 deaths). Patients experiencing the primary outcome were older and more likely to have a history of atrial arrhythmia. The primary outcome was highest in those with both moderate/severe right ventricular (RV) dysfunction and tricuspid regurgitation (n = 110, 31 events) and uncommon in those with mild/less RV dysfunction and tricuspid regurgitation (n = 181, 13 events, P < .001). Outcomes were not different based on anatomic complexity and history of tricuspid valve surgery or of subpulmonic obstruction. New CHF admission or ventricular arrhythmia was associated with the primary outcome. Individuals who underwent childhood surgery had more adverse outcomes than age- and sex-matched controls. Multivariable Cox regression analysis identified older age, prior CHF admission, and severe RV dysfunction as independent predictors for the primary outcome. CONCLUSIONS: Patients with ccTGA have variable deterioration to end-stage heart failure or death over time, commonly between their fifth and sixth decades. Predictors include arrhythmic and CHF events and severe RV dysfunction but not anatomy or need for tricuspid valve surgery.


Assuntos
Insuficiência Cardíaca , Transposição dos Grandes Vasos , Insuficiência da Valva Tricúspide , Disfunção Ventricular Direita , Adulto , Humanos , Feminino , Criança , Adulto Jovem , Pessoa de Meia-Idade , Masculino , Transposição das Grandes Artérias Corrigida Congenitamente , Estudos Retrospectivos , Transposição dos Grandes Vasos/complicações , Transposição dos Grandes Vasos/cirurgia , Insuficiência da Valva Tricúspide/complicações , Disfunção Ventricular Direita/complicações , Insuficiência Cardíaca/complicações
4.
PLoS Pathog ; 18(10): e1010860, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36264855

RESUMO

Global banana production is currently challenged by Panama disease, caused by Fusarium oxysporum f.sp. cubense Tropical Race 4 (FocTR4). There are no effective fungicide-based strategies to control this soil-borne pathogen. This could be due to insensitivity of the pathogen to fungicides and/or soil application per se. Here, we test the effect of 12 single-site and 9 multi-site fungicides against FocTR4 and Foc Race1 (FocR1) in quantitative colony growth, and cell survival assays in purified FocTR4 macroconidia, microconidia and chlamydospores. We demonstrate that these FocTR4 morphotypes all cause Panama disease in bananas. These experiments reveal innate resistance of FocTR4 to all single-site fungicides, with neither azoles, nor succinate dehydrogenase inhibitors (SDHIs), strobilurins or benzimidazoles killing these spore forms. We show in fungicide-treated hyphae that this innate resistance occurs in a subpopulation of "persister" cells and is not genetically inherited. FocTR4 persisters respond to 3 µg ml-1 azoles or 1000 µg ml-1 strobilurins or SDHIs by strong up-regulation of genes encoding target enzymes (up to 660-fold), genes for putative efflux pumps and transporters (up to 230-fold) and xenobiotic detoxification enzymes (up to 200-fold). Comparison of gene expression in FocTR4 and Zymoseptoria tritici, grown under identical conditions, reveals that this response is only observed in FocTR4. In contrast, FocTR4 shows little innate resistance to most multi-site fungicides. However, quantitative virulence assays, in soil-grown bananas, reveals that only captan (20 µg ml-1) and all lipophilic cations (200 µg ml-1) suppress Panama disease effectively. These fungicides could help protect bananas from future yield losses by FocTR4.


Assuntos
Fungicidas Industriais , Fusarium , Musa , Fungicidas Industriais/farmacologia , Succinato Desidrogenase , Estrobilurinas , Captana , Xenobióticos , Doenças das Plantas/genética , Esporos Fúngicos , Solo , Azóis , Benzimidazóis
5.
J Feline Med Surg ; 24(6): 473-483, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-34251296

RESUMO

OBJECTIVES: The aim of this study was to evaluate the outcome and prognosis of thoracolumbar feline intervertebral disc disease (IVDD) treated by surgical decompression. METHODS: This was a multi-institutional retrospective study evaluating the age, breed, sex, body weight, presenting complaint, neuroanatomic diagnosis at presentation, diagnostic imaging results, surgery performed and the overall outcome at discharge and at recheck. Bivariable associations between variables were assessed using the Kruskal-Wallis test (age and grade of IVDD at presentation) and Fisher's exact test (grade of IVDD at presentation and outcome). RESULTS: A total of 35 cats met the inclusion criteria for the study. The most frequently reported clinical sign was difficulty walking (54.2%). The majority of cats presented with an L4-S3 localization (57%). The most common site of intervertebral disc herniation (IVDH) was at L6-L7 (34%). The majority of feline patients that received surgery had a positive outcome at the time of discharge (62.5%; n = 20/32) and at the time of the 2-week recheck (91.3%; n = 21/23). No association was identified between the age of the patient and the grade of IVDD. No association was identified between the presenting grade of IVDD and the clinical outcome at the time of discharge or at the time of recheck evaluation. CONCLUSIONS AND RELEVANCE: Cats undergoing spinal decompressive surgery for thoracolumbar IVDH appear to have a favorable prognosis independent of the initial presenting grade of IVDD. A larger sample size and a longer length of follow-up is necessary to obtain statistical associations between the presenting grade of IVDD and overall clinical outcome.


Assuntos
Doenças do Gato , Degeneração do Disco Intervertebral , Deslocamento do Disco Intervertebral , Animais , Peso Corporal , Doenças do Gato/cirurgia , Gatos , Degeneração do Disco Intervertebral/cirurgia , Degeneração do Disco Intervertebral/veterinária , Deslocamento do Disco Intervertebral/cirurgia , Deslocamento do Disco Intervertebral/veterinária , Estudos Retrospectivos
6.
Front Cardiovasc Med ; 8: 651496, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33959642

RESUMO

Thirty four-year-old male with history of D-transposition of the great arteries (D-TGA) who underwent Mustard operation at 14 months of age presented in cardiogenic shock secondary to severe systemic right ventricular failure. Catheterization revealed significantly increased pulmonary pressures. Due to the patient's inotrope dependence and prohibitive pulmonary hypertension, he underwent implantation of a Heart Ware HVAD® for systemic RV support. Within 4 months of continuous flow ventricular assist device (VAD) implantation complete normalization of pulmonary vascular resistance (PVR) was achieved. He ultimately underwent orthotopic heart transplantation with favorable outcomes. This is the second report of complete normalization of PVR following VAD implantation into a systemic RV in <4 months. We conducted a thorough literature review to identify Mustard patients that received systemic RV VAD as a bridge to a successful heart transplantation. In this article, we summarize the outcomes and focus on pulmonary hypertension reversibility following VAD implant.

7.
Cardiol Young ; 31(1): 84-90, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33081854

RESUMO

BACKGROUND: Cardiopulmonary exercise testing performance has been shown to be a predictor of morbidity, mortality, and quality of life in patients with Fontan physiology; however, the role of exercise performance along with other diagnostics is not fully understood. We evaluated the hypothesis that reduced exercise performance correlates with poorer quality of life in Fontan patients as they continue to age. METHODS: Chart review was performed on patients 12 years and older with Fontan who had completed cardiopulmonary exercise testing and age-appropriate quality of life surveys. Quality of life outcomes were analysed against exercise performance and other descriptive data. RESULTS: For the younger cohort (n = 22), exercise performance predicted quality of life with different measures across domains and had a stronger correlation than echocardiographic parameters. For the older cohort (n = 34), exercise performance did not predict quality of life. CONCLUSIONS: Objective exercise performance was a useful marker for general, physical, emotional, social, and school quality of life in a younger cohort but less helpful in older adults. This is perhaps due to older patients accommodating to their conditions over time. The role of exercise performance and objective data in predicting quality of life in patients with Fontan physiology is incompletely understood and additional prospective evaluation should be undertaken.


Assuntos
Técnica de Fontan , Cardiopatias Congênitas , Idoso , Teste de Esforço , Tolerância ao Exercício , Cardiopatias Congênitas/cirurgia , Humanos , Estudos Prospectivos , Qualidade de Vida
8.
Nat Food ; 1(6): 332-342, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37128085

RESUMO

Emerging fungal and oomycete pathogens infect staple calorie crops and economically important commodity crops, thereby posing a significant risk to global food security. Our current agricultural systems - with emphasis on intensive monoculture practices - and globalized markets drive the emergence and spread of new pathogens and problematic traits, such as fungicide resistance. Climate change further promotes the emergence of pathogens on new crops and in new places. Here we review the factors affecting the introduction and spread of pathogens and current disease control strategies, illustrating these with the historic example of the Irish potato famine and contemporary examples of soybean rust, wheat blast and blotch, banana wilt and cassava root rot. Our Review looks to the future, summarizing what we see as the main challenges and knowledge gaps, and highlighting the direction that research must take to face the challenge of emerging crop pathogens.

9.
J Anim Ecol ; 89(1): 186-206, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31424571

RESUMO

The paradigm-changing opportunities of biologging sensors for ecological research, especially movement ecology, are vast, but the crucial questions of how best to match the most appropriate sensors and sensor combinations to specific biological questions and how to analyse complex biologging data, are mostly ignored. Here, we fill this gap by reviewing how to optimize the use of biologging techniques to answer questions in movement ecology and synthesize this into an Integrated Biologging Framework (IBF). We highlight that multisensor approaches are a new frontier in biologging, while identifying current limitations and avenues for future development in sensor technology. We focus on the importance of efficient data exploration, and more advanced multidimensional visualization methods, combined with appropriate archiving and sharing approaches, to tackle the big data issues presented by biologging. We also discuss the challenges and opportunities in matching the peculiarities of specific sensor data to the statistical models used, highlighting at the same time the large advances which will be required in the latter to properly analyse biologging data. Taking advantage of the biologging revolution will require a large improvement in the theoretical and mathematical foundations of movement ecology, to include the rich set of high-frequency multivariate data, which greatly expand the fundamentally limited and coarse data that could be collected using location-only technology such as GPS. Equally important will be the establishment of multidisciplinary collaborations to catalyse the opportunities offered by current and future biologging technology. If this is achieved, clear potential exists for developing a vastly improved mechanistic understanding of animal movements and their roles in ecological processes and for building realistic predictive models.


Assuntos
Ecologia , Movimento , Animais
10.
Microbiol Resour Announc ; 8(36)2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31488538

RESUMO

We present a high-quality draft genome assembly for Fusarium oxysporum f. sp. cubense tropical race 4 (Fusarium odoratissimum), assembled from PacBio reads and consisting of 15 contigs with a total assembly size of 48.59 Mb. This strain appears to belong to vegetative compatibility group complex 01213/16.

11.
Cardiol Young ; 29(8): 1045-1050, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31250770

RESUMO

BACKGROUND: The initial classic Fontan utilising a direct right atrial appendage to pulmonary artery anastomosis led to numerous complications. Adults with such complications may benefit from conversion to a total cavo-pulmonary connection, the current standard palliation for children with univentricular hearts. METHODS: A single institution, retrospective chart review was conducted for all Fontan conversion procedures performed from July, 1999 through January, 2017. Variables analysed included age, sex, reason for Fontan conversion, age at Fontan conversion, and early mortality or heart transplant within 1 year after Fontan conversion. RESULTS: A total of 41 Fontan conversion patients were identified. Average age at Fontan conversion was 24.5 ± 9.2 years. Dominant left ventricular physiology was present in 37/41 (90.2%) patients. Right-sided heart failure occurred in 39/41 (95.1%) patients and right atrial dilation was present in 33/41 (80.5%) patients. The most common causes for Fontan conversion included atrial arrhythmia in 37/41 (90.2%), NYHA class II HF or greater in 31/41 (75.6%), ventricular dysfunction in 23/41 (56.1%), and cirrhosis or fibrosis in 7/41 (17.1%) patients. Median post-surgical follow-up was 6.2 ± 4.9 years. Survival rates at 30 days, 1 year, and greater than 1-year post-Fontan conversion were 95.1, 92.7, and 87.8%, respectively. Two patients underwent heart transplant: the first within 1 year of Fontan conversion for heart failure and the second at 5.3 years for liver failure. CONCLUSIONS: Fontan conversion should be considered early when atrial arrhythmias become common rather than waiting for severe heart failure to ensue, and Fontan conversion can be accomplished with an acceptable risk profile.


Assuntos
Técnica de Fontan/métodos , Complicações Pós-Operatórias/etiologia , Adolescente , Adulto , Arritmias Cardíacas/etiologia , Arritmias Cardíacas/mortalidade , Feminino , Átrios do Coração/cirurgia , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/mortalidade , Transplante de Coração , Ventrículos do Coração/cirurgia , Humanos , Imageamento Tridimensional , Falência Hepática/etiologia , Falência Hepática/mortalidade , Masculino , Morbidade , Complicações Pós-Operatórias/mortalidade , Artéria Pulmonar/cirurgia , Estudos Retrospectivos , Taxa de Sobrevida , Tomografia Computadorizada por Raios X , Falha de Tratamento , Disfunção Ventricular/etiologia , Disfunção Ventricular/mortalidade , Adulto Jovem
12.
Congenit Heart Dis ; 14(4): 511-516, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30945809

RESUMO

BACKGROUND: Delivery of care to the adult congenital heart disease (ACHD) population has been limited by a shortage in the ACHD physician resources. There is limited data regarding the adequacy of the ACHD physician resources in the United States and our population estimates are extrapolated from Canadian data. Therefore, we proposed to evaluate the adequacy of ACHD physician: patient ratios in the United States at both national and regional levels. METHODS: Data from the Adult Congenital Heart Association (ACHA) website along with metropolitan area and statewide population data from 2016 US Census Bureau estimates were analyzed. Physicians listed on the ACHA website were cross-referenced with ABIM to verify ACHD board certification status. RESULTS: There are 115 self-identified ACHD programs and 418 self-identified ACHD physicians listed in the ACHA website. There are 320 board-certified ACHD cardiologists in the United States today, including 161 not listed in the ACHA website. Regarding ratios of ACHD-certified physicians to patients, the best served metropolitan statistical area (MSA) is Raleigh-Cary, NC, and the worst served MSA is Riverside-San Bernardino-Ontario, CA. The best served State is Washington, DC, and the worst served State is Indiana. CONCLUSIONS: The ACHD population continues to grow, and the looming national physician shortage is likely to greatly affect the ability to meet the complex needs of this growing population. In order to bring the ACHD patient: physician ratio to 1000:1, a minimum of 170 additional ACHD board-certified physicians are needed now.


Assuntos
Cardiologistas/provisão & distribuição , Cardiologia , Atenção à Saúde/organização & administração , Recursos em Saúde/provisão & distribuição , Cardiopatias Congênitas/epidemiologia , Sociedades Médicas , Recursos Humanos/tendências , Adulto , Humanos , Ontário , Estudos Retrospectivos , Estados Unidos
13.
Fungal Genet Biol ; 128: 14-19, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30876892

RESUMO

Zymoseptoria tritici, the causal agent of Septoria tritici blotch, is a notable pathogen of temperate-grown wheat. To better understand the mechanisms underpinning pathogenicity, leaf infection assays are commonly used to compare either the virulence of Z. tritici wildtype or mutant strains, or the susceptibility of wheat cultivars. These assays, which control for many biotic, abiotic and experimental variables, involve the application of known spore numbers to leaves. To achieve this, spore numbers are quantified during a period of aqueous suspension. Published methods rarely state the period in which spores are held in suspension, suggesting that this variable may be uncontrolled. Using simple, agar-based plating experiments, this work firstly demonstrates that blastospore culturability (the ability to form a colony when plated on appropriate agar) decreases rapidly over time during maintenance in aqueous suspension. It is subsequently shown that this reduction in culturability correlates to a reduction in the virulence of the blastospore population. This is shown in three wild type Z. tritici strains. From this, it is concluded that suspension time is a variable of major importance in experimental design and one which, if not controlled, may lead to erroneous conclusions from inter-strain comparisons. The conidia of the unrelated fungus Magnaporthe oryzae also rapidly lose culturability when stored in aqueous suspension, whereas the microspores of Fusarium oxysporum f. sp. cubense do not, suggesting that this phenomenon occurs in some but not all other fungi. Finally, a droplet method of inoculations is proposed to decrease the variability in the numbers of spores applied, within and between experiments.


Assuntos
Ascomicetos/patogenicidade , Técnicas Microbiológicas/métodos , Esporos Fúngicos/fisiologia , Contagem de Colônia Microbiana , Viabilidade Microbiana , Triticum/microbiologia , Virulência
14.
Can Vet J ; 59(7): 755-758, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-30026622

RESUMO

A 1-year-old neutered male Labrador retriever mixed breed dog was referred for peracute onset of ataxia and seizures. Hematocrit at presentation was 84%. Magnetic resonance imaging of the brain revealed a lesion in the right caudate nucleus consistent with infarction. Postmortem findings were consistent with polycythemia vera and presumed secondary cerebral infarction.


Événement cérébrovasculaire aigu chez un chien atteint de polycythémie vraie. Un Labrador retriever mâle âgé de 1 an a été référé pour l'apparition suraiguë d'ataxie et de crises d'épilepsie. L'hématocrite était de 84 % à la présentation. L'imagerie par résonance magnétique du cerveau a révélé une lésion dans le noyau caudé droit compatible avec à un infarcissement. Les résultats post mortem étaient conformes à une polycythémie vraie et à un infarcissement cérébral secondaire présumé.(Traduit par Isabelle Vallières).


Assuntos
Infarto Cerebral/veterinária , Doenças do Cão/patologia , Policitemia Vera/veterinária , Animais , Ataxia/veterinária , Encéfalo/diagnóstico por imagem , Infarto Cerebral/etiologia , Doenças do Cão/diagnóstico por imagem , Doenças do Cão/etiologia , Cães , Imageamento por Ressonância Magnética/veterinária , Masculino , Policitemia Vera/complicações , Policitemia Vera/patologia , Convulsões/veterinária
15.
Fungal Genet Biol ; 106: 51-60, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28694096

RESUMO

Zymoseptoria tritici causes Septoria leaf blotch of wheat. The prevailing paradigm of the Z. tritici-wheat interaction assumes fungal ingress through stomata within 24-48h, followed by days of symptomless infection. This is extrapolated from studies testing the mode of fungal ingress under optimal infection conditions. Here, we explicitly assess the timing of entry, using GFP-tagged Z. tritici. We show that early entry is comparatively rare, and extended epiphytic growth possible. We test the hypotheses that our data diverge from earlier studies due to: i. random ingress of Z. tritici into the leaf, with some early entry events; ii. previous reliance upon fungal stains, combined with poor attachment of Z. tritici to the leaf, leading to increased likelihood of observing internal versus external growth, compared to using GFP; iii. use of exceptionally high humidity to promote entry in previous studies. We combine computer simulation of leaf-surface growth with thousands of in planta observations to demonstrate that while spores germinate rapidly on the leaf, over 95% of fungi remain epiphytic, growing randomly over the leaf for ten days or more. We show that epiphytic fungi are easily detached from leaves by rinsing and that humidity promotes epiphytic growth, increasing infection rates. Together, these results explain why epiphytic growth has been dismissed and early ingress assumed. The prolonged epiphytic phase should inform studies of pathogenicity and virulence mutants, disease control strategies, and interpretation of the observed low in planta growth, metabolic quiescence and evasion of plant defences by Zymoseptoria during symptomless infection.


Assuntos
Ascomicetos/crescimento & desenvolvimento , Ascomicetos/patogenicidade , Umidade , Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia , Triticum/microbiologia , Análise de Variância , Ascomicetos/efeitos dos fármacos , Ascomicetos/isolamento & purificação , Benzimidazóis/farmacologia , Carbamatos/farmacologia , Fungicidas Industriais/farmacologia , Fosfitos/farmacologia , Doenças das Plantas/prevenção & controle , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/fisiologia , Fatores de Tempo
16.
PeerJ ; 3: e957, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26082869

RESUMO

Colonial pinnipeds may be subject to substantial consumptive competition because they are large, slow-moving central place foragers. We examined possible mechanisms for reducing this competition by examining the diving behaviour of harbour seals (Phoca vitulina) after equipping 34 seals (11 females, 23 males) foraging from three locations; Rømø, Denmark and Lorenzenplate and Helgoland, Germany, in the Wadden Sea area with time-depth recorders. Analysis of 319,021 dives revealed little between-colony variation but appreciable inter-sex differences, with males diving deeper than females, but for shorter periods. Males also had higher vertical descent rates. This result suggests that males may have higher overall swim speeds, which would increase higher oxygen consumption, and may explain the shorter dive durations compared to females. Intersex variation in swim speed alone is predicted to lead to fundamental differences in the time use of three-dimensional space, which may help reduce consumptive competition in harbour seals and other colonial pinnipeds.

17.
Infect Immun ; 76(11): 5341-9, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18794278

RESUMO

Salmonella enterica serovar Typhi can establish a chronic, asymptomatic infection of the human gallbladder, suggesting that this bacterium utilizes novel mechanisms to mediate enhanced colonization and persistence in a bile-rich environment. Gallstones are one of the most important risk factors for developing carriage, and we have previously demonstrated that salmonellae form biofilms on human gallstones in vitro. Thus, we hypothesize that bile-induced biofilms on gallstone surfaces promote gallbladder colonization and maintenance of the carrier state. A colanic acid/cellulose S. enterica serovar Typhimurium double mutant formed a mature biofilm on gallstones in a test tube assay and in a new, gallstone-independent assay using cholesterol-coated Eppendorf tubes. These data suggest the presence of an unidentified exopolysaccharide necessary for mature biofilm development and demonstrate specific binding affinity between salmonellae and cholesterol. Our experiments indicate that the Salmonella O-antigen capsule (yihU-yshA and yihV-yihW) is a crucial determinant in gallstone and cholesterol biofilms but that expression of this exopolysaccharide is not necessary for binding to glass or plastic. Real-time PCR revealed that growth in bile resulted in upregulation of the O-antigen capsule-encoding operon in an agfD-independent manner. Thus, the O-antigen capsule genes are bile induced, and the capsule produced by the enzymes of this operon is specifically required for biofilm formation on cholesterol gallstones. These studies provide new therapeutic targets for preventing asymptomatic serovar Typhi gallbladder carriage.


Assuntos
Bile/microbiologia , Biofilmes/crescimento & desenvolvimento , Cálculos Biliares/microbiologia , Antígenos O/metabolismo , Salmonella typhi/fisiologia , Cápsulas Bacterianas/genética , Cápsulas Bacterianas/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Bile/metabolismo , Colesterol/metabolismo , Ensaio de Imunoadsorção Enzimática , Matriz Extracelular/metabolismo , Imunofluorescência , Regulação Bacteriana da Expressão Gênica , Humanos , Microscopia Eletrônica de Varredura , Antígenos O/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Infecções por Salmonella/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
18.
J Mol Microbiol Biotechnol ; 13(1-3): 55-64, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17693713

RESUMO

The psychrophilic bacterium Flavobacterium psychrophilum is a rapidly emerging, virulent pathogen of a variety of commercially important finfish species, including salmonids. No vaccines against F. psychrophilum are currently available, partly due to its recalcitrant growth in vitro. Consequently, we explored the possibility of constructing recombinant vaccines in Escherichia coli as a prophylactic biotechnological strategy to counter F. psychrophilum infections. An immunoreactive clone from a F. psychrophilum expression library was found to express a approximately 16 kDa protein antigen. A proteomics approach was taken to identify the ORF encoding the approximately 16 kDa protein. Tryptic fragments of the approximately 16 kDa protein were analyzed by MALDI-TOF mass spectrometry and compared to theoretical (in silico) tryptic fragments of translated ORFs predicted within the cloned DNA. The target protein was identified as a 166 amino acid protein (named 7-166) with homology to rplJ which encodes bacterial ribosomal protein L10. Whenhighly expressed in E. coli as an N-terminal fusion protein, this chimera reacted with convalescent rainbow trout serum. When adjuvanted and administered intraperitoneally to immature rainbow trout a high level of protection (82% RPS) was afforded against virulent F. psychrophilum challenge; thus establishing F. psychrophilumrplJ homologue 7-166 as a promising vaccine candidate for RTFS.


Assuntos
Vacinas Bacterianas/imunologia , Doenças dos Peixes/imunologia , Flavobacterium/imunologia , Oncorhynchus mykiss/imunologia , Animais , Antígenos de Bactérias/genética , Antígenos de Bactérias/imunologia , Antígenos de Bactérias/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/metabolismo , Vacinas Bacterianas/genética , Western Blotting , Eletroforese em Gel Bidimensional , Eletroforese em Gel de Poliacrilamida , Doenças dos Peixes/microbiologia , Infecções por Flavobacteriaceae/imunologia , Infecções por Flavobacteriaceae/microbiologia , Flavobacterium/genética , Flavobacterium/metabolismo , Biblioteca Gênica , Oncorhynchus mykiss/microbiologia , Proteínas Recombinantes/química , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/metabolismo , Proteína Ribossômica L10 , Proteínas Ribossômicas/genética , Proteínas Ribossômicas/imunologia , Proteínas Ribossômicas/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
19.
Carbohydr Res ; 341(14): 2388-97, 2006 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-16857179

RESUMO

Salmonella enteritidis is a food-borne enteric human pathogen that can form a complex protective extracellular matrix. We describe here a component of this matrix which is distinct from other known salmonella extracellular polysaccharides such as cellulose and colanic acid. We have used glycosyl composition and linkage analysis, as well as 1D and 2D NMR spectroscopy to determine the structure of this polysaccharide. We propose that the primary saccharide in the S. enteritidis capsule has a branched tetrasaccharide repeating unit having the following structure: -->3)-alpha-D-Galp-(1-->2)-[alpha-Tyvp-(1-->3)]-alpha-D-Manp-(1-->4)-alpha-L-Rhap-(1-->. This structure is partially substituted on both tyvelose and galactose with a glucose-containing side chain. It further bears considerable similarity to the O antigen from this organism, a feature found in a number of other capsules from Gram-negative bacteria. In addition, we have detected fatty acids at levels that indicate the presence of a lipid anchor.


Assuntos
Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/isolamento & purificação , Salmonella enteritidis/química , Configuração de Carboidratos , Sequência de Carboidratos , Matriz Extracelular/química , Ácidos Graxos/análise , Glicosilação , Espectroscopia de Ressonância Magnética
20.
FEBS J ; 273(13): 3002-13, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16759227

RESUMO

Lipopolysaccharide (LPS) and beta-glucan from Francisella victoria, a fish pathogen and close relative of highly virulent mammal pathogen Francisella tularensis, have been analyzed using chemical and spectroscopy methods. The polysaccharide part of the LPS was found to contain a nonrepetitive sequence of 20 monosaccharides as well as alanine, 3-aminobutyric acid, and a novel branched amino acid, thus confirming F. victoria as a unique species. The structure identified composes the largest oligosaccharide elucidated by NMR so far, and was possible to solve using high field NMR with cold probe technology combined with the latest pulse sequences, including the first application of H2BC sequence to oligosaccharides. The non-phosphorylated lipid A region of the LPS was identical to that of other Francisellae, although one of the lipid A components has not been found in Francisella novicida. The heptoseless core-lipid A region of the LPS contained a linear pentasaccharide fragment identical to the corresponding part of F. tularensis and F. novicida LPSs, differing in side-chain substituents. The linkage region of the O-chain also closely resembled that of other Francisella. LPS preparation contained two characteristic glucans, previously observed as components of LPS preparations from other strains of Francisella: amylose and the unusual beta-(1-6)-glucan with (glycerol)2phosphate at the reducing end.


Assuntos
Peixes/microbiologia , Francisella/metabolismo , Lipopolissacarídeos/química , beta-Glucanas/química , Alanina/química , Aminobutiratos/química , Animais , Western Blotting , Sequência de Carboidratos , Glucanos/química , Espectroscopia de Ressonância Magnética , Modelos Químicos , Dados de Sequência Molecular , Fosforilação
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