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1.
Phytopathology ; : PHYTO01240010SC, 2024 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-38427684

RESUMO

Clustered regularly interspaced short palindromic repeats (CRISPR) has been widely characterized as a defense system against phages and other invading elements in bacteria and archaea. A low percentage of Ralstonia solanacearum species complex (RSSC) strains possess the CRISPR array and the CRISPR-associated proteins (Cas) that would confer immunity against various phages. To provide a wide-range screen of the CRISPR presence in the RSSC, we analyzed 378 genomes of RSSC strains to find the CRISPR locus. We found that 20.1, 14.3, and 54.5% of the R. solanacearum, R. pseudosolanacearum, and R. syzygii strains, respectively, possess the CRISPR locus. In addition, we performed further analysis to identify the respective phages that are restricted by the CRISPR arrays. We found 252 different phages infecting different strains of the RSSC, by means of the identification of similarities between the protospacers in phages and spacers in bacteria. We compiled this information in a database with web access called CRISPRals (https://crisprals.yachaytech.edu.ec/). Additionally, we made available a number of tools to detect and identify CRISPR array and Cas genes in genomic sequences that could be uploaded by users. Finally, a matching tool to relate bacteria spacer with phage protospacer sequences is available. CRISPRals is a valuable resource for the scientific community that contributes to the study of bacteria-phage interaction and a starting point that will help to design efficient phage therapy strategies.

2.
Int J Mol Sci ; 24(10)2023 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-37240236

RESUMO

Back pain is the single leading cause of disability worldwide. Despite the prevalence and morbidity of lower back pain, we still lack a gold-standard treatment that restores the physiological function of degenerated intervertebral discs. Recently, stem cells have emerged as a promising strategy for regenerative therapy for degenerative disc disease. In this study, we review the etiology, pathogenesis, and developing treatment strategies for disc degeneration in low back pain with a focus on regenerative stem cell therapies. A systematic search of PubMed/MEDLINE/Embase/Clinical Trials.gov databases was conducted for all human subject abstracts or studies. There was a total of 10 abstracts and 11 clinical studies (1 RCT) that met the inclusion criteria. The molecular mechanism, approach, and progress of the different stem cell strategies in all studies are discussed, including allogenic bone marrow, allogenic discogenic cells, autologous bone marrow, adipose mesenchymal stem cells (MSCs), human umbilical cord MSC, adult juvenile chondrocytes, autologous disc derived chondrocytes, and withdrawn studies. Clinical success with animal model studies is promising; however, the clinical outcomes of stem cell regenerative therapy remain poorly understood. In this systematic review, we found no evidence to support its use in humans. Further studies on efficacy, safety, and optimal patient selection will establish whether this becomes a viable, non-invasive therapeutic option for back pain.


Assuntos
Degeneração do Disco Intervertebral , Disco Intervertebral , Dor Lombar , Transplante de Células-Tronco Mesenquimais , Adulto , Animais , Humanos , Dor Lombar/terapia , Dor Lombar/etiologia , Degeneração do Disco Intervertebral/patologia , Transplante de Células-Tronco Mesenquimais/efeitos adversos , Dor nas Costas/patologia , Disco Intervertebral/patologia
3.
Biol Sport ; 39(1): 45-51, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35173362

RESUMO

We examined the degree to which 200-m and 400-m Individual Medley (IM) performance was related to sprint-, middle- and long-distance events before a swimmer reached a Top-20 world ranking. A retrospective longitudinal modelling study was conducted. Data on Top-20 swimmers between 2010 and 2018 were obtained from publicly available websites. A general linear model was used to examine associations between 200-m and 400-mIM performance (FINA ranking points) and performance in sprint, middle-distance and distance events in the previous two years. In the 200-mIM, there were significant associations (p < 0.001) between prior competition results obtained for both the 200-mIM (r = 0.80; ß = 0.543) and 400-m IM (r = 0.70; ß = 0.317) events before the Top-20 performance in 200-mIM in the year of the Top-20. Sprint distance events were associated (p < 0.006; r = 0.39; ß = 0.088) with 200-mIM (t). Each additional 10 FINA points in the 200-mIM in each of the two years preceding the Top-20 performance. were associated with an increase of 5 FINA points in 200-mIM in in the year of the Top-20 (goodness of fit R 2 = 0.70). There were similar associations (p < 0.001) for a Top 20-FINA 400-mIM performance with both 200-mIM (r = 0.72; ß = 0.385) and 400-m IM (r = 0.79; ß = 0.492) events in the two years before a swimmer reached the Top-20. Middle-distance events were associated with 400-mIM performance (p < 0.001; r = 0.53; ß = 0.163). Each additional 10 FINA points in 400-mIM in in each of the two years preceding the Top-20 performance were associated with an increase of 5 FINA points in in the year that a swimmer reached the Top-20 (goodness of fit R 2 = 0.75). The specificity and complexity of the IM require a thorough preparation in this event for world-class performances. The 200-mIM is more closely related to sprint distance events, whereas middle-distance events support preparations for the 400-mIM.

4.
BMC Evol Biol ; 19(1): 123, 2019 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-31208326

RESUMO

BACKGROUND: Plant pathogens are under significant selective pressure by the plant host. Consequently, they are expected to have adapted to this condition or contribute to evading plant defenses. In order to acquire long-term fitness, plant bacterial pathogens are usually forced to maintain advantageous genetic diversity in populations. This strategy ensures that different alleles in the pathogen's gene pool are maintained in a population at frequencies larger than expected under neutral evolution. This selective process, known as balancing selection, is the subject of this work in the context of a common bacterial phytopathogen. We performed a genome-wide scan of Ralstonia solanacearum species complex, an aggressive plant bacterial pathogen that shows broad host range and causes a devastating disease called 'bacterial wilt'. RESULTS: Using a sliding window approach, we analyzed 57 genomes from three phylotypes of the R. solanacearum species complex to detect signatures of balancing selection. A total of 161 windows showed extreme values in three summary statistics of population genetics: Tajima's D, θw and Fu & Li's D*. We discarded any confounding effects due to demographic events by means of coalescent simulations of genetic data. The prospective windows correspond to 78 genes with known function that map in any of the two main replicons (1.7% of total number of genes). The candidate genes under balancing selection are related to primary metabolism and other basal activities (51.3%) or directly associated to virulence (48.7%), the latter being involved in key functions targeted to dismantle plant defenses or to participate in critical stages in the pathogenic process. CONCLUSIONS: We identified various genes under balancing selection that play a significant role in basic metabolism as well as in virulence of the R. solanacearum species complex. These genes are useful to understand and monitor the evolution of bacterial pathogen populations and emerge as potential candidates for future treatments to induce specific plant immune responses.


Assuntos
Ralstonia solanacearum/genética , Ralstonia solanacearum/patogenicidade , Evolução Biológica , Genoma Bacteriano , Especificidade de Hospedeiro , Doenças das Plantas/microbiologia , Plantas , Estudos Prospectivos , Ralstonia solanacearum/citologia , Virulência
5.
Rev Biol Trop ; 64(2): 427-48, 2016 Jun.
Artigo em Espanhol | MEDLINE | ID: mdl-29451378

RESUMO

Seagrasses in coastal environments have been threatened by increased human activities; these have negatively altered processes and environmental services, and have decreased grassland areas. The aim of this study was to generate knowledge of Thalassia testudinum distribution, state of the structure and fragmentation level in two reefs of the Veracruz Reef System National Park (PNSAV). Two different reefs were selected: Sacrificios in the North and near the coast, and Cabezo in the South and away from the coast. Shoot-specific and area-specific characteristics of submerged macrophytes meadows present were determined, and four morpho-functional groups were identified. Significant differences between plant coverage were tested through nonparametric ANOVA, Kruskal-Wallis test. A supervised classification of spatial high-resolution image verified with field data was performed (55 Sacrificios and 290 Cabezo). The fragmentation level was calculated using landscape metrics, class level and thematic maps were made based on four covers. The meadows were dominated by Thalassia testudinum; maximum densities were 208 shoot/m2 in Cabezo, and 176 shoot/m2 in Sacrificios. Cabezo presented grasses with short (9 cm) and thin leaves (0.55 cm) on average; while Sacrificios showed longer (23.5 cm) and thicker (1 cm) leaves. Sacrificios showed lower fragmentation degree than Cabezo; in both cases, the vegetation cover fragmentation corresponded to less than 50 %. Although Cabezo reef presents further fragmentation, which creates a large number of microenvironments, being recognized for its importance as recruitment area. This work serves as a baseline for the creation of an adequate management plan (formation of a core area of Cabezo). It is necessary to complement this work with new efforts for the recognition of seagrass prairies in all PNSAV reefs, as well as periodic monitoring and recognition of ecosystem services. .


Assuntos
Hydrocharitaceae/classificação , Conservação dos Recursos Naturais , Recifes de Corais , México , Densidade Demográfica , Dinâmica Populacional
6.
Phytopathology ; 105(5): 597-607, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25710204

RESUMO

Phylogeographic studies inform about routes of pathogen dissemination and are instrumental for improving import/export controls. Genomes of 17 isolates of the bacterial wilt and potato brown rot pathogen Ralstonia solanacearum race 3 biovar 2 (R3bv2), a Select Agent in the United States, were thus analyzed to get insight into the phylogeography of this pathogen. Thirteen of fourteen isolates from Europe, Africa, and Asia were found to belong to a single clonal lineage while isolates from South America were genetically diverse and tended to carry ancestral alleles at the analyzed genomic loci consistent with a South American origin of R3bv2. The R3bv2 isolates share a core repertoire of 31 type III-secreted effector genes representing excellent candidates to be targeted with resistance genes in breeding programs to develop durable disease resistance. Toward this goal, 27 R3bv2 effectors were tested in eggplant, tomato, pepper, tobacco, and lettuce for induction of a hypersensitive-like response indicative of recognition by cognate resistance receptors. Fifteen effectors, eight of them core effectors, triggered a response in one or more plant species. These genotypes may harbor resistance genes that could be identified and mapped, cloned, and expressed in tomato or potato, for which sources of genetic resistance to R3bv2 are extremely limited.


Assuntos
Genômica , Doenças das Plantas/microbiologia , Ralstonia solanacearum/genética , Solanum tuberosum/microbiologia , África , Ásia , Capsicum/imunologia , Capsicum/microbiologia , Resistência à Doença , Europa (Continente) , Variação Genética , Lactuca/imunologia , Lactuca/microbiologia , Solanum lycopersicum/imunologia , Solanum lycopersicum/microbiologia , Filogeografia , Doenças das Plantas/imunologia , Ralstonia solanacearum/patogenicidade , Solanum melongena/genética , Solanum melongena/imunologia , Solanum tuberosum/imunologia , América do Sul , Virulência
7.
Appl Opt ; 52(33): 8040-7, 2013 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-24513755

RESUMO

New diagnostics are presented that use a digital camera to measure full-field soot temperatures and soot volume fractions in axisymmetric flames. The camera is a Nikon D700 with 12 megapixels and 14 bit depth in each color plane, which was modified by removing the infrared and anti-aliasing filters. The diagnostics were calibrated with a blackbody furnace. The flame considered here was an 88 mm long ethylene/air co-flowing laminar jet diffusion flame on a round 11.1 mm burner. The resolution in the flame plane is estimated at between 0.1 and 0.7 mm. Soot temperatures were measured from soot radiative emissions, using ratio pyrometry at 450, 650, and 900 nm following deconvolution. These had a range of 1600-1850 K, a temporal resolution of 125 ms, and an estimated uncertainty of ±50 K. Soot volume fractions were measured two ways: from soot radiative emissions and from soot laser extinction at 632.8 nm, both following deconvolution. Soot volume fractions determined from emissions had a range of 0.1-10 ppm, temporal resolutions of 125 ms, and an estimated uncertainty of ±30%. Soot volume fractions determined from laser extinction had a range of 0.2-10 ppm, similar temporal resolutions, and an estimated uncertainty of ±10%. The present measurements agree with past measurements in this flame using traversing optics and probes; however, they avoid the long test times and other complications of such traditional methods.

8.
Adicciones ; 25(1): 63-70, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23487281

RESUMO

The aim of the present study was to analyze: (a) the relationship between alcohol and tobacco use and academic performance, and (b) the predictive role of psycho-educational factors and alcohol and tobacco abuse on academic performance in a sample of 352 Spanish adolescents from grades 8 to 10 of Compulsory Secondary Education. The Self-Description Questionnaire-II, the Sydney Attribution Scale, and the Achievement Goal Tendencies Questionnaire were administered in order to analyze cognitive-motivational variables. Alcohol and tobacco abuse, sex, and grade retention were also measured using self-reported questions. Academic performance was measured by school records. Frequency analyses and logistic regression analyses were used. Frequency analyses revealed that students who abuse of tobacco and alcohol show a higher rate of poor academic performance. Logistic regression analyses showed that health behaviours, and educational and cognitive-motivational variables exert a different effect on academic performance depending on the academic area analyzed. These results point out that not only academic, but also health variables should be address to improve academic performance in adolescence.


Assuntos
Consumo de Bebidas Alcoólicas/epidemiologia , Consumo de Bebidas Alcoólicas/psicologia , Cognição , Escolaridade , Motivação , Uso de Tabaco/epidemiologia , Uso de Tabaco/psicologia , Adolescente , Estudos Transversais , Feminino , Humanos , Masculino , Instituições Acadêmicas , Espanha/epidemiologia , Inquéritos e Questionários
9.
World Neurosurg ; 179: 143, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37619841

RESUMO

Spinal arachnoid webs are abnormal formations of arachnoid membranes that reside in the arachnoid space. Clinically, they may present as an incidental finding or in patients with progressively worsening myelopathy. Early detection and surgical intervention are recommended in patients with progressive symptoms. Several methods have been described for the surgical treatment of these web formations.1-4 The success of surgery and the ability to prevent recurrence is dependent on complete surgical resection of these lesions, which in some cases can appear complex and intricate in nature. A few reports have highlighted the use of intraoperative ultrasound to localize the lesion; however, none have highlighted its value in establishing successful web resection and restoration of normal cerebrospinal fluid flow.3,4 Herein, we demonstrate the use of intraoperative ultrasound as an effective adjunct to assessing and establishing complete resection of arachnoid webs. We illustrate how intraoperative ultrasound allows for real-time, direct visualization of arachnoid lysis with restoration of normal cerebrospinal fluid flow (Video 1). Our patient was symptomatic for 12 months with rapid progression of myelopathic symptoms in the 3 months before presentation. Following surgery, she remained asymptomatic at 4-year follow-up with no reoccurrence at 24-month magnetic resonance imaging. Intraoperative ultrasound is a useful adjunct to successfully performing dorsal arachnoid web surgery and ensuring improved surgical outcomes through complete web resection and decompression of the spinal cord.


Assuntos
Cistos Aracnóideos , Doenças da Medula Espinal , Feminino , Humanos , Doenças da Medula Espinal/diagnóstico por imagem , Doenças da Medula Espinal/cirurgia , Imageamento por Ressonância Magnética , Aracnoide-Máter/diagnóstico por imagem , Aracnoide-Máter/cirurgia , Ultrassonografia , Cistos Aracnóideos/diagnóstico por imagem , Cistos Aracnóideos/cirurgia
10.
Radiol Case Rep ; 18(5): 1924-1928, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37069953

RESUMO

Pressure control cam dislocation is a rare finding in patients with a programmable shunt valve that should be considered when evaluating patients with signs and symptoms of shunt malfunction. The objective of this paper is to review the mechanism, clinical presentation, and radiographic findings associated with pressure control cam (PCC) dislocation, in addition to presenting a novel case to add to the scarce literature on this topic. A systematic review of the literature were performed using PubMed, Embase, and Cochrane from database inception. PCC dislocation is exceedingly rare and can present with no symptoms, positional headache, neck pain, nausea, or vomiting. Skull x-ray findings demonstrate a clear black "X" at the distal end of the valve, due to the PCC disarticulation from atop the base plate of the plastic valve housing. Intraoperatively, a "Y"-shaped crack atop the plastic valve housing may be present and the PCC may be fully separated from the shunt or found at the distal end of the plastic valve housing. Prior reports of dislocation of the PCC have occurred 7-9 years after implantation, with inciting events including direct trauma, programmable valve adjustment, and utilization 3-Tesla magnetic resonance image scan.

11.
J Physiol ; 590(17): 4239-53, 2012 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-22753549

RESUMO

The interaction of either H(+) or Cl(-) ions with the fast gate is the major source of voltage (V(m)) dependence in ClC Cl(-) channels. However, the mechanism by which these ions confer V(m) dependence to the ClC-2 Cl(-) channel remains unclear. By determining the V(m) dependence of normalized conductance (G(norm)(V(m))), an index of open probability, ClC-2 gating was studied at different [H(+)](i), [H(+)](o) and [Cl(-)](i). Changing [H(+)](i) by five orders of magnitude whilst [Cl(-)](i)/[Cl(-)](o) = 140/140 or 10/140 mm slightly shifted G(norm)(V(m)) to negative V(m) without altering the onset kinetics; however, channel closing was slower at acidic pH(i). A similar change in [H(+)](o) with [Cl(-)](i)/[Cl(-)](o) = 140/140 mm enhanced G(norm) in a bell-shaped manner and shifted G(norm)(V(m)) curves to positive V(m). Importantly, G(norm) was >0 with [H(+)](o) = 10(-10) m but channel closing was slower when [H(+)](o) or [Cl(-)](i) increased implying that ClC-2 was opened without protonation and that external H(+) and/or internal Cl(-) ions stabilized the open conformation. The analysis of kinetics and steady-state properties at different [H(+)](o) and [Cl(-)](i) was carried out using a gating Scheme coupled to Cl(-) permeation. Unlike previous results showing V(m)-dependent protonation, our analysis revealed that fast gate protonation was V(m) and Cl(-) independent and the equilibrium constant for closed­open transition of unprotonated channels was facilitated by elevated [Cl(-)](i) in a V(m)-dependent manner. Hence a V(m) dependence of pore occupancy by Cl(-) induces a conformational change in unprotonated closed channels, before the pore opens, and the open conformation is stabilized by Cl(-) occupancy and V(m)-independent protonation.


Assuntos
Canais de Cloreto/metabolismo , Animais , Canais de Cloro CLC-2 , Canais de Cloreto/química , Canais de Cloreto/genética , Cloretos/metabolismo , Fenômenos Eletrofisiológicos , Células HEK293 , Humanos , Concentração de Íons de Hidrogênio , Ativação do Canal Iônico , Cinética , Camundongos , Modelos Biológicos , Conformação Proteica , Prótons , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
12.
J Allergy Clin Immunol Pract ; 10(9): 2438-2447.e9, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35568331

RESUMO

BACKGROUND: The clinical approach to upper and lower respiratory diseases from a joint perspective, known as united airways disease (UAD), is challenging for health care professionals owing to a paucity of specific studies. OBJECTIVE: This study reviews recent scientific evidence on the management of asthma and chronic rhinosinusitis with nasal polyps (CRSwNP) from a UAD perspective. METHODS: A systematic search of PubMed, Scopus, and Web of Science was conducted for 9 research questions, and studies published from January 2015 to July 2021 were included. Quality assessment was performed with the Critical Appraisal Skills Programme. RESULTS: In total, 32 publications met the inclusion criteria. Control of type 2 inflammation in UAD (reported in 9 studies) was associated with biologic therapies, for which an impact on asthma, CRSwNP, and/or aspirin/nonsteroidal anti-inflammatory drug-exacerbated respiratory disease outcomes was described in 9 studies. However, there was a lack of scientific evidence on clinical and/or biochemical markers associated with response to biologics in patients with UAD. The benefit on corticosteroid reduction in patients receiving biologics was reported in 9 studies. Three publications reported a positive impact of surgery on asthma and/or CRSwNP outcomes, and the effect of biologics on reducing the need of surgery was consistent across 6 studies. CONCLUSIONS: Our results underscore an overall scarcity of scientific evidence on the treatment strategies for these frequent coexisting entities from an UAD approach but also identify several research gaps and unmet needs that should be addressed to ensure optimal diagnosis, management, and follow-up of these patients.


Assuntos
Asma Induzida por Aspirina , Asma , Produtos Biológicos , Pólipos Nasais , Transtornos Respiratórios , Rinite , Sinusite , Asma/tratamento farmacológico , Asma/epidemiologia , Asma Induzida por Aspirina/tratamento farmacológico , Produtos Biológicos/uso terapêutico , Doença Crônica , Humanos , Pólipos Nasais/complicações , Pólipos Nasais/epidemiologia , Pólipos Nasais/terapia , Rinite/tratamento farmacológico , Sinusite/tratamento farmacológico
13.
J Environ Biol ; 32(4): 395-9, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22315818

RESUMO

Trichodesmium erythraeum Ehrenberg ex Gomont is a microalga worldwide distributed in tropical seas. This filamentous microalga was detected in phytoplankton samples collected in the Protected NaturalArea "Parque Nacional SistemaArrecifal Veracruzano", and because of its ecological importance, its temporal dynamics was studied using net samples (30 microm) collected in one year period. Samples were studied with a light microscope recording the presence, morphological characteristics, life form and relative abundance. Trichodesmium erythraeum occurred as single filaments and was rare in April 2007 and March 2008; as single filaments from May to August and December 2007; as single filaments and small aggregates in September 2007 and January 2008; in aggregates of large size (> 3mm) and high relative abundance in October 2007; and was absence in November 2007 and April 2008. Although the relative abundance of the species was not important comparing with other members of phytoplankton, its occurrence was frequent with a bloom at the beginning of the north winds period. The observed temporal dynamics of this microalga in this coral reef region comes up on the alert in the monitoring red tides programs being implemented in Veracruz coast.


Assuntos
Microalgas/fisiologia , Ecossistema , Monitoramento Ambiental , Golfo do México , Dinâmica Populacional , Fatores de Tempo
14.
J Neurosci ; 29(10): 3242-51, 2009 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-19279261

RESUMO

The neuronal subthreshold-operating A-type K(+) current regulates electrical excitability, spike timing, and synaptic integration and plasticity. The Kv4 channels underlying this current have been implicated in epilepsy, regulation of dopamine release, and pain plasticity. However, the unitary conductance (gamma) of neuronal somatodendritic A-type K(+) channels composed of Kv4 pore-forming subunits is larger (approximately 7.5 pS) than that of Kv4 channels expressed singly in heterologous cells (approximately 4 pS). Here, we examined the putative novel contribution of the dipeptidyl-peptidase-like protein-6 DPP6-S to the gamma of native [cerebellar granule neuron (CGN)] and reconstituted Kv4.2 channels. Coexpression of Kv4.2 proteins with DPP6-S was sufficient to match the gamma of native CGN channels; and CGN Kv4 channels from dpp6 knock-out mice yielded a gamma indistinguishable from that of Kv4.2 channels expressed singly. Moreover, suggesting electrostatic interactions, charge neutralization mutations of two N-terminal acidic residues in DPP6-S eliminated the increase in gamma. Therefore, DPP6-S, as a membrane protein extrinsic to the pore domain, is necessary and sufficient to explain a fundamental difference between native and recombinant Kv4 channels. These observations may help to understand the molecular basis of neurological disorders correlated with recently identified human mutations in the dpp6 gene.


Assuntos
Proteínas do Tecido Nervoso/fisiologia , Neurônios/fisiologia , Peptídeo Hidrolases/fisiologia , Canais de Potássio/fisiologia , Canais de Potássio Shal/fisiologia , Animais , Dipeptidil Peptidases e Tripeptidil Peptidases/deficiência , Dipeptidil Peptidases e Tripeptidil Peptidases/fisiologia , Feminino , Potenciais da Membrana/fisiologia , Camundongos , Camundongos Knockout , Proteínas do Tecido Nervoso/deficiência , Neurônios/enzimologia , Peptídeo Hidrolases/deficiência , Canais de Potássio/deficiência , Ratos , Canais de Potássio Shal/deficiência , Xenopus laevis
15.
J Physiol ; 588(Pt 14): 2545-56, 2010 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-20498235

RESUMO

It has been shown that the voltage (V(m)) dependence of ClC Cl(-) channels is conferred by interaction of the protopore gate with H(+) ions. However, in this paper we present evidence which indicates that permeant Cl(-) ions contribute to V(m)-dependent gating of the broadly distributed ClC-2 Cl() channel. The apparent open probability (P(A)) of ClC-2 was enhanced either by changing the [Cl(-)](i) from 10 to 200 mM or by keeping the [Cl(-)](i) low (10 mM) and then raising [Cl(-)](o) from 10 to 140 mM. Additionally, these changes in [Cl(-)] slowed down channel closing at positive V(m) suggesting that high [Cl(-)] increased pore occupancy thus hindering closing of the protopore gate. The identity of the permeant anion was also important since the P(A)(V(m)) curves were nearly identical with Cl(-) or Br(-) but shifted to negative voltages in the presence of SCN() ions. In addition, gating, closing rate and reversal potential displayed anomalous mole fraction behaviour in a SCN(-)/Cl() mixture in agreement with the idea that pore occupancy by different permeant anions modifies the V(m) dependence ClC-2 gating. Based on the ec1-ClC anion pathway, we hypothesized that opening of the protopore gate is facilitated when Cl(-) ions dwell in the central binding site. In contrast, when Cl(-) ions dwell in the external binding site they prevent the gate from closing. Finally, this Cl(-)-dependent gating in ClC-2 channels is of physiological relevance since an increase in [Cl(-)](o) enhances channel opening when the [Cl(-)](i) is in the physiological range.


Assuntos
Canais de Cloreto/fisiologia , Cloretos/fisiologia , Ativação do Canal Iônico/fisiologia , Animais , Canais de Cloro CLC-2 , Células Cultivadas , Cloretos/metabolismo , Camundongos , Glândula Parótida/fisiologia , Tiocianatos/farmacologia
16.
Pflugers Arch ; 460(3): 633-44, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20454973

RESUMO

The volume-sensitive chloride current (I(ClVol)) exhibit a time-dependent decay presumably due to channel inactivation. In this work, we studied the effects of chloride ions (Cl(-)) and H(+) ions on I(ClVol) decay recorded in HEK-293 and HL-60 cells using the whole-cell patch clamp technique. Under control conditions ([Cl(-)](e) = [Cl(-)](i) = 140 mM and pH(i) = pH(e) = 7.3), I(ClVol) in HEK cells shows a large decay at positive voltages but in HL-60 cells I(ClVol) remained constant independently of time. In HEK-293 cells, simultaneously raising the [Cl(-)](e) and [Cl(-)](i) from 25 to 140 mM (with pH(e) = pH(i) = 7.3) increased the fraction of inactivated channels (FIC). This effect was reproduced by elevating [Cl(-)](i) while keeping the [Cl(-)](e) constant. Furthermore, a decrease in pH(e) from 7.3 to 5.5 accelerated current decay and increased FIC when [Cl(-)] was 140 mM but not 25 mM. In HL-60 cells, a slight I(ClVol) decay was seen when the pH(e) was reduced from 7.3 to 5.5. Our data show that inactivation of I(ClVol) can be controlled by changing either the Cl(-) or H(+) concentration or both. Based on our results and previously published data, we have built a model that explains VRAC inactivation. In the model the H(+) binding site is located outside the electrical field near the extracellular entry whilst the Cl(-) binding site is intracellular. The model depicts inactivation as a pore constriction that happens by simultaneous binding of H(+) and Cl(-) ions to the channel followed by a voltage-dependent conformational change that ultimately causes inactivation.


Assuntos
Cloretos/metabolismo , Prótons , Canais de Ânion Dependentes de Voltagem/metabolismo , Células HL-60 , Humanos , Concentração de Íons de Hidrogênio , Líquido Intracelular/metabolismo , Cinética , Técnicas de Patch-Clamp
17.
Glycoconj J ; 27(2): 277-85, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20041292

RESUMO

Iminosugars are monosaccharide analogues that have been demonstrated to be specific inhibitors for glycosidases and are currently used therapeutically in several human disorders. N-alkylated derivatives of D-fagomine and (2R,3S,4R,5S)-2-(hydroxymethyl)-5-methylpyrrolidine-3,4-diol with aliphatic chains were tested in eight human cancer cell lines to analyze their cytotoxicity and the inhibitory effect in the activities of specific glycosidases. Results indicate that these compounds were more cytotoxic as the length of the alkyl chain increases. N-dodecyl-D-fagomine inhibited specifically the alpha-D-glucosidase activity in cell lysates, whereas no effect was detected in other glycosidases. The N-dodecyl derivative of (2R,3S,4R,5S)-2-(Hydroxymethyl)-5-methylpyrrolidine-3,4-diol induced specific inhibition against alpha-L-fucosidase in cell lysates. Our results indicated that the length of the alkyl chain linked to the iminosugars determine their cytotoxicity as well as the inhibitory effect on the enzymatic activities of specific glycosidases, in human cancer cell lines.


Assuntos
Glicosídeo Hidrolases/antagonistas & inibidores , Imino Piranoses/farmacologia , Pirrolidinas/farmacologia , Morte Celular/efeitos dos fármacos , Extratos Celulares , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Glucosídeos/metabolismo , Glicosídeos/metabolismo , Humanos , Imino Piranoses/química , Fenótipo , Pirrolidinas/química
18.
Phytopathology ; 100(3): 208-15, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20128693

RESUMO

Although there are adequate DNA sequence differences among plant-associated and plant-pathogenic bacteria to facilitate molecular approaches for their identification, identification at a taxonomic level that is predictive of their phenotype is a challenge. The problem is the absence of a taxonomy that describes genetic variation at a biologically relevant resolution and of a database containing reference strains for comparison. Moreover, molecular evolution, population genetics, ecology, and epidemiology of many plant-pathogenic and plant-associated bacteria are still poorly understood. To address these challenges, a database with web interface was specifically designed for plant-associated and plant-pathogenic microorganisms. The Plant-Associated Microbes Database (PAMDB) comprises, thus far, data from multilocus sequence typing and analysis (MLST/MLSA) studies of Acidovorax citrulli, Pseudomonas syringae, Ralstonia solanacearum, and Xanthomonas spp. Using data deposited in PAMDB, a robust phylogeny of Xanthomonas axonopodis and related bacteria has been inferred, and the diversity existing in the Xanthomonas genus and in described Xanthomonas spp. has been compared with the diversity in P. syringae and R. solanacearum. Moreover, we show how PAMDB makes it easy to distinguish between different pathogens that cause almost identical diseases. The scalable design of PAMDB will make it easy to add more plant pathogens in the future.


Assuntos
Bactérias/genética , Bases de Dados Factuais , Internet , Doenças das Plantas/microbiologia , Plantas/microbiologia , Biologia Computacional , Filogenia
19.
Rhinology ; 48(1): 35-40, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20502733

RESUMO

INTRODUCTION: Rhinitis and asthma share epidemiological, pathophysiological, and clinical features. The aim of the RINOASMAIR study was to examine the prevalence and characteristics of rhinitis in asthmatics in a Primary Care setting in Spain. METHODS: A prospective epidemiological study was conducted with the participation of 1,027 Primary Care Physicians (PCP). A total of 4,174 asthmatics were included and demographic data, rhinitis prevalence, lung function, atopy, and rhinitis treatment were analysed. RESULTS: 71% of asthmatics suffered from rhinitis, these being younger (42.8 vs 50.2 yr; p<0.0001) and having milder asthma (FEV1=80.2% vs 76.1%, p<0.002) than those with-out rhinitis. A significant correlation (Rho=0.35, p<0.0001) between asthma and rhinitis severities was found. Atopy was associated to rhinitis, 77.8% of atopic compared to 47.6% of non atopic having rhinitis. CONCLUSIONS: Most asthmatics (71%) visited by Spanish PCP suffer from rhinitis, and these patients are younger and have milder asthma than asthmatics without rhinitis.


Assuntos
Asma/epidemiologia , Rinite/epidemiologia , Asma/tratamento farmacológico , Asma/fisiopatologia , Comorbidade , Humanos , Prevalência , Atenção Primária à Saúde , Estudos Prospectivos , Testes de Função Respiratória , Rinite/tratamento farmacológico , Rinite/fisiopatologia , Índice de Gravidade de Doença , Espanha/epidemiologia
20.
Span J Psychol ; 13(1): 138-55, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20480684

RESUMO

Schools play a key role in transmitting attitudes towards sexual diversity. Many studies stress the importance of teachers' and other professionals' attitudes towards gay men and/or lesbian women. This study evaluates attitudes and prejudices toward homosexuality in a sample of 254 elementary and high school teachers in Barcelona and its surrounding area. The results obtained using a scale of overt and subtle prejudice and a scale of perceived discrepancy of values indicate that discrepancy between likely behavior and personal values was significantly greater in women, those who hold religious beliefs, churchgoers and people without any gay or lesbian acquaintances. Approximately 88% of the teachers showed no type of prejudiced attitudes towards gay men and lesbian women. The experience of proximity to gay men and/or lesbian women reduces not only the discrepancy between personal values and likely behavior but also the presence of homophobic prejudice. It would be advisable to expand specific teacher training in the subject of sexual diversity in order to reduce prejudicial attitudes, thus fostering non-stereotyped knowledge of homosexuality.


Assuntos
Atitude , Docentes , Homossexualidade Feminina/psicologia , Homossexualidade Masculina/psicologia , Preconceito , Estereotipagem , Adulto , Feminino , Humanos , Capacitação em Serviço , Masculino , Pessoa de Meia-Idade , Distância Psicológica , Religião e Psicologia , Comportamento Sexual , Espanha , Inquéritos e Questionários , Adulto Jovem
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