Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 39
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Small ; : e1906892, 2020 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-32091185

RESUMO

Lateral heterostructures consisting of 2D transition metal dichalcogenides (TMDCs) directly interfaced with molecular networks or nanowires can be used to construct new hybrid materials with interesting electronic and spintronic properties. However, chemical methods for selective and controllable bond formation between 2D materials and organic molecular networks need to be developed. As a demonstration of a self-assembled organic nanowire-TMDC system, a method to link and interconnect epitaxial single-layer MoS2 flakes with organic molecules is demonstrated. Whereas pristine epitaxial single-layer MoS2 has no affinity for molecular attachment, it is found that single-layer MoS2 will selectively bind the organic molecule 2,8-dibromodibenzothiophene (DBDBT) in a surface-assisted Ullmann coupling reaction when the MoS2 has been activated by pre-exposing it to hydrogen. Atom-resolved scanning tunneling microscopy (STM) imaging is used to analyze the bonding of the nanowires, and thereby it is revealed that selective bonding takes place on a specific S atom at the corner site between the two types of zig-zag edges available in a hexagonal single layer MoS2 sheet. The method reported here successfully combining synthesis of epitaxial TMDCs and Ullmann coupling reactions on surfaces may open up new synthesis routes for 2D organic-TMDC hybrid materials.

2.
J Bras Pneumol ; 46(1): e20180328, 2020.
Artigo em Inglês, Português | MEDLINE | ID: mdl-31859814

RESUMO

OBJECTIVE: To evaluate the relationship that the difference between slow vital capacity (SVC) and FVC (ΔSVC-FVC) has with demographic, clinical, and pulmonary function data. METHODS: This was an analytical cross-sectional study in which participants completed a respiratory health questionnaire, as well as undergoing spirometry and plethysmography. The sample was divided into two groups: ΔSVC-FVC ≥ 200 mL and ΔSVC-FVC < 200 mL. The intergroup correlations were analyzed, and binomial logistic regression analysis was performed. RESULTS: The sample comprised 187 individuals. In the sample as a whole, the mean ΔSVC-FVC was 0.17 ± 0.14 L, and 61 individuals (32.62%) had a ΔSVC-FVC ≥ 200 mL. The use of an SVC maneuver reduced the prevalence of nonspecific lung disease and of normal spirometry results by revealing obstructive lung disease (OLD). In the final logistic regression model (adjusted for weight and body mass index > 30 kg/m2), OLD and findings of air trapping (high functional residual capacity and a low inspiratory capacity/TLC ratio) were predictors of a ΔSVC-FVC ≥ 200 mL. The chance of a bronchodilator response was found to be greater in the ΔSVC-FVC ≥ 200 mL group: for FEV1 (OR = 4.38; 95% CI: 1.45-13.26); and for FVC (OR = 3.83; 95% CI: 1.26-11.71). CONCLUSIONS: The use of an SVC maneuver appears to decrease the prevalence of nonspecific lung disease and of normal spirometry results. Individuals with a ΔSVC-FVC ≥ 200 mL, which is probably the result of OLD and air trapping, are apparently more likely to respond to bronchodilator administration.

3.
PLoS One ; 14(12): e0226652, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31846489

RESUMO

Glucose is an important nutrient that dictates the development, fertility and lifespan of all organisms. In humans, a deficit in its homeostatic control might lead to hyperglucemia and the development of obesity and type 2 diabetes, which show a decreased ability to respond to and metabolize glucose. Previously, we have reported that high-glucose diets (HGD) induce alterations in triglyceride content, body size, progeny, and the mRNA accumulation of key regulators of carbohydrate and lipid metabolism, and longevity in Caenorhabditis elegans (PLoS ONE 13(7): e0199888). Herein, we show that increasing amounts of glucose in the diet induce the swelling of both mitochondria in germ and muscle cells. Additionally, HGD alter the enzymatic activities of the different respiratory complexes in an intricate pattern. Finally, we observed a downregulation of ceramide synthases (hyl-1 and hyl-2) and antioxidant genes (gcs-1 and gst-4), while mitophagy genes (pink-1 and dct-1) were upregulated, probably as part of a mitohormetic mechanism in response to glucose toxicity.

4.
Sci Rep ; 9(1): 10094, 2019 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-31300693

RESUMO

In Mexico, HPV vaccines available immunize against genotypes 16/18 and 16/18/6/11; however, there is limited surveillance about carcinogenic subtypes in different states of the country that allow evaluating the effectiveness of vaccination and cervical cancer screening programs. Here, we report the regional and age-specific prevalence of 14 hr-HPV genotypes as well as their prevalence in abnormal cytology (from ASCUS to cervical cancer) among Mexican women which were undergoing from cervical cancer screening in the Salud Digna clinics in 20 states of the country. This study includes women with social security from the majority of public health institutions (IMSS, ISSSTE, SEMAR, and PEMEX), and women without social security. For cervical cancer screening, we used the SurePath liquid-based cytology and the BD Onclarity HPV Assay. From December 1, 2016, to August 2, 2018, the hr-HPV prevalence among 60,135 women was 24.78%, the most prevalent types were HPV 16 (4.13%), HPV 31 (4.12%) and HPV 51 (3.39%), while HPV 18 (1.70%) was less prevalent among infected women. Interestingly, the genotypes not covered by current vaccines in Mexico were commonly found in precancerous lesions, evidencing their carcinogenic potential, so it is necessary to increase their surveillance and inclusion in cervical cancer screening triage.

5.
J Chem Phys ; 150(4): 041731, 2019 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-30709272

RESUMO

Mixed metal oxides of earth-abundant 3d transition metals are an interesting class of materials that show interesting magnetic properties and a significant synergistic effect as catalysts for electrochemical oxygen evolution compared to simple unary oxides. However, the exact atomic-scale nature of such mixed oxide phases and the link to their interesting physico-chemical properties are poorly understood. Here, a combination of scanning tunneling microscopy and x-ray photoemission spectroscopy reveals that Fe species embed in a facile way into CoO bilayers on Au(111) resulting in an Fe doped oxide. Density functional theory and the spectroscopic fingerprint from x-ray photoemission spectroscopy reveal that the Fe dopants in the cobalt oxide matrix assume a higher oxidation state than in the structurally corresponding unary bilayer oxide. Furthermore, the substituted Fe is structurally displaced further away from the Au than the metal in either of the corresponding pure unary oxides. Both O and to a smaller extent Co in the nearest coordination shell are also structurally and electronically perturbed. The interesting effects observed in the bilayer binary oxides may enable a better fundamental understanding of the nature of doping of metal oxides, in general, and promotion effects in catalytic applications.

6.
Mar Drugs ; 17(2)2019 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-30759848

RESUMO

The isolation and structural elucidation of a structurally new desertomycin, designated as desertomycin G (1), with strong antibiotic activity against several clinically relevant antibiotic resistant pathogens are described herein. This new natural product was obtained from cultures of the marine actinomycete Streptomyces althioticus MSM3, isolated from samples of the intertidal seaweed Ulva sp. collected in the Cantabrian Sea (Northeast Atlantic Ocean). Particularly interesting is its strong antibiotic activity against Mycobacterium tuberculosis clinical isolates, resistant to antibiotics in clinical use. To the best of our knowledge, this is the first report on a member of the desertomycin family displaying such activity. Additionally, desertomycin G shows strong antibiotic activities against other relevant Gram-positive clinical pathogens such as Corynebacterium urealyticum, Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes, Enterococcus faecium, Enterococcus faecalis, and Clostridium perfringens. Desertomycin G also displays moderate antibiotic activity against relevant Gram-negative clinical pathogens such as Bacteroides fragilis, Haemophilus influenzae and Neisseria meningitidis. In addition, the compound affects viability of tumor cell lines, such as human breast adenocarcinoma (MCF-7) and colon carcinoma (DLD-1), but not normal mammary fibroblasts.


Assuntos
Antibióticos Antineoplásicos/farmacologia , Antituberculosos/farmacologia , Macrolídeos/farmacologia , Microalgas/microbiologia , Mycobacterium tuberculosis/efeitos dos fármacos , Streptomyces/química , Produtos Biológicos/química , Produtos Biológicos/farmacologia , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Humanos , Microalgas/classificação , Testes de Sensibilidade Microbiana
7.
Rev. costarric. cardiol ; 20(2): 22-36, dic. 2018. tab, graf
Artigo em Espanhol | LILACS-Express | ID: biblio-990967

RESUMO

Resumen La insuficiencia cardiaca es una de las principales enfermedades a nivel cardiaco debido a su mayor riesgo de mortalidad y de hospitalizaciones por descompensaciones agudas o por presencia de novo de falla cardiaca, por eso en los últimos años se desarrollaron a partir de estudios clínicos randomizados, medicamentos que mejoraran estos eventos, a partir del estudio PARADIGM-HF. Con el surgimiento de sacubitril/valsartan se evaluó su efecto en diferentes escenarios, así el enfoque de este artículo se basa en la revisión de artículos con el objetivo de analizar la importancia de los efectos be neficiosos del sacubitril/valsartan en comparación con enalapril en diferentes análisis y subestudios basado en el estudio PARADIGM-HF, en los cuales se evaluó el impacto del sacubitril/valsartan en diabetes mellitus tipo 2, en la función renal, hipertensión arterial, a nivel de mortalidad y seguridad, a nivel de edad, de hiperkalemia e hiperkalemia severa, en los factores asociados con la falta de cumplimiento durante el período de ejecución antes de la aleatorización y la influen cia en el beneficio estimado de sacubitril/valsartan en el ensayo PARADIGM-HF, eficacia de sacubitril/valsartan con dosis metas bajas, tolerabilidad y seguridad en el inicio de sacubitril/valsartan en insuficiencia cardiaca, efectos de sacubitril/ valsartan asociado a antagonistas de receptores de mineralocorticoides en la reducción de hiperkalemia, implicaciones en el pronóstico de los pacientes con insuficiencia cardiaca con fracción de eyección reducida con los cambios de pépti dos natriuréticos, eficacia y seguridad de sacubitril/valsartan en distintos rangos de edades, efecto del fármaco sobre la terapia de fondo utilizada en insuficiencia cardiaca y eficacia e influencia de sacubitril/valsartan en la fracción de eyección y desenlace primario.


Abstract Descriptores: sacubitril/valsartan, enalapril, insuficiencia cardiaca, péptidos natriureticos Heart failure is one of the main diseases at the cardiac level due to its higher risk of mortality and hospitalizations due to acute decompensation or de novo heart failure, which is why in recent years they were developed from randomized clinical trials. medicines that will improve these events, from there and from the PARADIGM-HF study. From the emergence of sacubitril / valsartan its effect was evaluated in different scenarios, hence the focus of this article was based on the review of articles and with the aim of analyzing the importance of the beneficial effects of sacubitril / valsartan compared to enalapril in different analyzes and substudies from the PARADIGM-HF study, which will evaluate the impact of sacubitril / valsartan in type 2 diabetes mellitus, in renal function, arterial hypertension, in terms of mortality and safety, in terms of age, hyperkalemia and severe hyperkalemia, in the factors associated with non-compliance during the execution period before randomization and the influence on the estimated benefit of sacubitril / valsartan in the PARADIGM-HF trial, efficacy of sacubitril / valsartan with low target doses , tolerability and safety at the onset of sacubitril / valsartan in heart failure, effects of sacubitril / valsartan associated with antag of mineralocorticoid receptors in the reduction of hyperkalemia, implications in the prognosis of patients with heart failure with reduced ejection fraction with changes in natriuretic peptides, efficacy and safety of sacubitril / valsartan in different age ranges, effect of the drug on the background therapy used in heart failure and the efficacy and influence of sacubitril / valsartan on the ejection fraction and primary outcome.

8.
PLoS One ; 13(7): e0199888, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29990370

RESUMO

High-glycemic-index diets, as well as a sedentary lifestyle are considered as determinant factors for the development of obesity, type 2 diabetes, and cardiovascular diseases in humans. These diets have been shown to shorten the life span of C. elegans in a manner that is dependent on insulin signaling, but the participation of other signaling pathways have not been addressed. In this study, we have determined that worms fed with high-glucose diets show alterations in glucose content and uptake, triglyceride content, body size, number of eggs laid, egg-laying defects, and signs of oxidative stress and accelerated aging. Additionally, we analyzed the participation of different key regulators of carbohydrate and lipid metabolism, oxidative stress and longevity such as SKN-1/NRF2, HIF-1/HIF1α, SBP-1/SREBP, CRH-1/CREB, CEP-1/p53, and DAF-16/FOXO, in the reduction of lifespan in glucose-fed worms.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Dieta da Carga de Carboidratos/efeitos adversos , Glucose/metabolismo , Estresse Fisiológico , Fatores de Transcrição/metabolismo , Envelhecimento/metabolismo , Animais , Caenorhabditis elegans/genética , Caenorhabditis elegans/crescimento & desenvolvimento , Proteínas de Caenorhabditis elegans/genética , Glucose/administração & dosagem , Oviparidade , Estresse Oxidativo , Fatores de Transcrição/genética , Triglicerídeos/metabolismo
9.
Angew Chem Int Ed Engl ; 57(37): 11893-11897, 2018 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-29981264

RESUMO

The catalytic synergy between cobalt oxide and gold leads to strong promotion of the oxygen evolution reaction (OER)-one half-reaction of electrochemical water splitting. However, the mechanism behind the enhancement effect is still not understood, in part due to a missing structural model of the active interface. Using a novel interplay of cyclic voltammetry (CV) for electrochemistry integrated with scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS) on an atomically defined cobalt oxide/Au(111) system, we reveal here that the supporting gold substrate uniquely favors a flexible cobalt-oxyhydroxide/Au interface in the electrochemically active potential window and thus suppresses the formation of less active bulk cobalt oxide morphologies. The findings substantiate why optimum catalytic synergy is obtained for oxide coverages on gold close to or below one monolayer, and provide the first morphological description of the active phase during electrocatalysis.

10.
Nat Commun ; 9(1): 2211, 2018 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-29880841

RESUMO

Hydrodesulfurization catalysis ensures upgrading and purification of fossil fuels to comply with increasingly strict regulations on S emissions. The future shift toward more diverse and lower-quality crude oil supplies, high in S content, requires attention to improvements of the complex sulfided CoMo catalyst based on a fundamental understanding of its working principles. In this study, we use scanning tunneling microscopy to directly visualize and quantify how reducing conditions transforms both cluster shapes and edge terminations in MoS2 and promoted CoMoS-type hydrodesulfurization catalysts. The reduced catalyst clusters are shown to be terminated with a fractional coverage of sulfur, representative of the catalyst in its active state. By adsorption of a proton-accepting molecular marker, we can furthermore directly evidence the presence of catalytically relevant S-H groups on the Co-promoted edge. The experimentally observed cluster structure is predicted by theory to be identical to the structure present under catalytic working conditions.

11.
Biomed Res Int ; 2018: 1925619, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29850485

RESUMO

Objective: To determine the frequency and distribution of ABO and Rh (D) antigens and, additionally, investigate gene diversity and the structure of Mexican populations. Materials and Methods: Blood groups were tested in 271,164 subjects from 2014 to 2016. The ABO blood group was determined by agglutination using the antibodies anti-A, Anti-B, and Anti-D for the Rh factor, respectively. Results: The overall distribution of ABO and Rh (D) groups in the population studied was as follows: O: 61.82%; A: 27.44%; B: 8.93%; and AB: 1.81%. For the Rh group, 95.58% of people were Rh (D), and 4.42% were Rh (d). Different distributions of blood groups across regions were found; additionally, genetic analysis revealed that the IO and ID allele showed an increasing trend from the north to the center, while the IA and Id allele tended to increase from the center to the north. Also, we found more gene diversity in both loci in the north compared with the center, suggesting population structure in Mexico. Conclusion: This work could help health institutions to identify where they can obtain blood products necessary for medical interventions. Moreover, this piece of information contributes to the knowledge of the genetic structure of the Mexican populations which could have significant implications in different fields of biomedicine.


Assuntos
Sistema do Grupo Sanguíneo ABO/genética , Frequência do Gene/genética , Sistema do Grupo Sanguíneo Rh-Hr/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Estudos Transversais , Feminino , Genética Populacional , Humanos , Lactente , Recém-Nascido , Masculino , México/epidemiologia , Pessoa de Meia-Idade , Filogenia , Adulto Jovem
12.
Chem Commun (Camb) ; 54(29): 3621-3624, 2018 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-29577149

RESUMO

We demonstrate a method to selectively switch the Ullmann coupling reaction of 2,8-dibromodibenzothiophene on a Au(111) support. The Ullmann coupling reaction is effective already at low temperature, but the complete inhibition of the same reaction can be achieved on Au(111) pre-exposed to H2S. The marked difference in reactivity of pretreated Au(111) is explained by the S-passivation of free Au atoms emerging from reconstruction sites. The inhibited state can be fully lifted by removing the S via hydrogen gas post-exposure.


Assuntos
Ouro/química , Polímeros/síntese química , Enxofre/química , Tiofenos/química , Hidrogênio/química , Sulfeto de Hidrogênio/química , Estrutura Molecular , Oxirredução , Polimerização , Polímeros/química
13.
J Phys Chem B ; 122(2): 561-571, 2018 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-28800235

RESUMO

Well-characterized metal oxides supported on single crystal surfaces serve as valuable model systems to study fundamental chemical properties and reaction mechanisms in heterogeneous catalysis or as new thin film metal oxide catalysts in their own right. Here, we present scanning tunneling microscopy and X-ray photoelectron spectroscopy results for cobalt oxide nanoislands that reveal the detailed atomistic mechanisms leading to transitions between Co-O bilayer and O-Co-O trilayer, induced by oxidation in O2 and reductive vacuum annealing treatments, respectively. By comparing between two different noble metal substrates, Au(111) and Pt(111), we further address the influence of the substrate. Overall, nanoisland edges act to initiate both the oxidation and reduction processes on both substrates. However, important influences of the choice of substrate were found, as the progress of oxidation includes intermediate steps on Au(111) not observed on Pt(111), where the oxidation on the other hand takes place at a significantly higher rate. During reductive treatment of trilayer, the bilayer structure gradually reappears on Pt(111), but not on Au(111) where the reduction rather results in the appearance of a stacked cobalt oxide morphology. These observations point to strong differences in the catalytic behavior between Au and Pt supported cobalt oxides, despite the otherwise strong structural similarities.

14.
Lab Med ; 49(1): e1-e8, 2017 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-29253199

RESUMO

Background: To validate the performance, reproducibility, and reliability of BD automated instruments in order to establish a fully automated clinical microbiology laboratory. Methods: We used control strains and clinical samples to assess the accuracy, reproducibility, and reliability of the BD Kiestra WCA, the BD Phoenix, and BD Bruker MALDI-Biotyper instruments and compared them to previously established conventional methods. The following processes were evaluated: sample inoculation and spreading, colony counts, sorting of cultures, antibiotic susceptibility test, and microbial identification. Results: The BD Kiestra recovered single colonies in less time than conventional methods (e.g. E. coli, 7h vs 10h, respectively) and agreement between both methodologies was excellent for colony counts (κ=0.824) and sorting cultures (κ=0.821). Antibiotic susceptibility tests performed with BD Phoenix and disk diffusion demonstrated 96.3% agreement with both methods. Finally, we compared microbial identification in BD Phoenix and Bruker MALDI-Biotyper and observed perfect agreement (κ=1) and identification at a species level for control strains. Together these instruments allow us to process clinical urine samples in 36h (effective time). Conclusion: The BD automated technologies have improved performance compared with conventional methods, and are suitable for its implementation in very busy microbiology laboratories.


Assuntos
Automação Laboratorial , Técnicas Bacteriológicas , Automação Laboratorial/instrumentação , Automação Laboratorial/métodos , Automação Laboratorial/normas , Carga Bacteriana , Técnicas Bacteriológicas/instrumentação , Técnicas Bacteriológicas/métodos , Técnicas Bacteriológicas/normas , Humanos , Testes de Sensibilidade Microbiana , Tipagem Molecular , Reprodutibilidade dos Testes , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
15.
J Am Chem Soc ; 139(40): 14129-14136, 2017 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-28889740

RESUMO

Expanded porphyrins are large-cavity macrocycles with enormous potential in coordination chemistry, anion sensing, photodynamic therapy, and optoelectronics. In the last two decades, the surface science community has assessed the physicochemical properties of tetrapyrrolic-like macrocycles. However, to date, the sublimation, self-assembly and atomistic insights of expanded porphyrins on surfaces have remained elusive. Here, we show the self-assembly on Au(111) of an expanded aza-porphyrin, namely, an "expanded hemiporphyrazine", through a unique growth mechanism based on long-range orientational self-assembly. Furthermore, a spatially controlled "writing" protocol on such self-assembled architecture is presented based on the STM tip-induced deprotonation of the inner protons of individual macrocycles. Finally, the capability of these surface-confined macrocycles to host lanthanide elements is assessed, introducing a novel off-centered coordination motif. The presented findings represent a milestone in the fields of porphyrinoid chemistry and surface science, revealing a great potential for novel surface patterning, opening new avenues for molecular level information storage, and boosting the emerging field of surface-confined coordination chemistry involving f-block elements.

16.
J Nat Prod ; 80(2): 569-573, 2017 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-28169531

RESUMO

Two new antibiotics, branimycins B (2) and C (3), were produced by fermentation of the abyssal actinobacterium Pseudonocardia carboxydivorans M-227, isolated from deep seawater of the Avilés submarine Canyon. Their structures were elucidated by HRMS and NMR analyses. These compounds exhibit antibacterial activities against a panel of Gram-positive bacteria, including Corynebacterium urealyticum, Clostridium perfringens, and Micrococcus luteus, and against the Gram-negative bacterium Neisseria meningitidis. Additionally, branimycin B displayed moderate antibacterial activity against other Gram-negative bacteria such as Bacteroides fragilis, Haemophilus influenzae, and Escherichia coli, and branimycin C against the Gram-positive Enterococcus faecalis and methicillin-sensitive and methicillin-resistant Staphylococcus aureus.


Assuntos
Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Macrolídeos/isolamento & purificação , Macrolídeos/farmacologia , Antibacterianos/química , Enterococcus faecalis , Bactérias Gram-Negativas , Bactérias Gram-Positivas , Haemophilus influenzae , Macrolídeos/química , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular
17.
Chromosoma ; 126(5): 615-631, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28101670

RESUMO

Homologous chromosomes exchange genetic information through recombination during meiosis, a process that increases genetic diversity, and is fundamental to sexual reproduction. In an attempt to shed light on the dynamics of mammalian recombination and its implications for genome organization, we have studied the recombination characteristics of 112 individuals belonging to 28 different species in the family Bovidae. In particular, we analyzed the distribution of RAD51 and MLH1 foci during the meiotic prophase I that serve, respectively, as proxies for double-strand breaks (DSBs) which form in early stages of meiosis and for crossovers. In addition, synaptonemal complex length and meiotic DNA loop size were estimated to explore how genome organization determines DSBs and crossover patterns. We show that although the number of meiotic DSBs per cell and recombination rates observed vary between individuals of the same species, these are correlated with diploid number as well as with synaptonemal complex and DNA loop sizes. Our results illustrate that genome packaging, DSB frequencies, and crossover rates tend to be correlated, while meiotic chromosomal axis length and DNA loop size are inversely correlated in mammals. Moreover, axis length, DSB frequency, and crossover frequencies all covary, suggesting that these correlations are established in the early stages of meiosis.


Assuntos
Cromossomos de Mamíferos/ultraestrutura , Meiose , Recombinação Genética , Ruminantes/genética , Complexo Sinaptonêmico/ultraestrutura , Animais , Cromossomos de Mamíferos/metabolismo , Quebras de DNA de Cadeia Dupla , Masculino , Camundongos , Proteína 1 Homóloga a MutL , Rad51 Recombinase , Ruminantes/metabolismo , Complexo Sinaptonêmico/metabolismo
18.
Microb Ecol ; 73(2): 338-352, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27614749

RESUMO

Marine Actinobacteria are emerging as an unexplored source for natural product discovery. Eighty-seven deep-sea coral reef invertebrates were collected during an oceanographic expedition at the submarine Avilés Canyon (Asturias, Spain) in a range of 1500 to 4700 m depth. From these, 18 cultivable bioactive Actinobacteria were isolated, mainly from corals, phylum Cnidaria, and some specimens of phyla Echinodermata, Porifera, Annelida, Arthropoda, Mollusca and Sipuncula. As determined by 16S rRNA sequencing and phylogenetic analyses, all isolates belong to the phylum Actinobacteria, mainly to the Streptomyces genus and also to Micromonospora, Pseudonocardia and Myceligenerans. Production of bioactive compounds of pharmacological interest was investigated by high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) techniques and subsequent database comparison. Results reveal that deep-sea isolated Actinobacteria display a wide repertoire of secondary metabolite production with a high chemical diversity. Most identified products (both diffusible and volatiles) are known by their contrasted antibiotic or antitumor activities. Bioassays with ethyl acetate extracts from isolates displayed strong antibiotic activities against a panel of important resistant clinical pathogens, including Gram-positive and Gram-negative bacteria, as well as fungi, all of them isolated at two main hospitals (HUCA and Cabueñes) from the same geographical region. The identity of the active extracts components of these producing Actinobacteria is currently being investigated, given its potential for the discovery of pharmaceuticals and other products of biotechnological interest.


Assuntos
Actinobacteria/química , Actinobacteria/classificação , Actinobacteria/isolamento & purificação , Antozoários/microbiologia , Produtos Biológicos/farmacologia , Filogenia , Actinobacteria/genética , Animais , Antibacterianos/farmacologia , Antineoplásicos/farmacologia , Bactérias/efeitos dos fármacos , Sequência de Bases , Biodiversidade , Produtos Biológicos/química , Produtos Biológicos/isolamento & purificação , Bioprospecção , Linhagem Celular Tumoral/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Classificação , Recifes de Corais , DNA Bacteriano , Ecossistema , Cromatografia Gasosa-Espectrometria de Massas , Genes Bacterianos , Invertebrados/microbiologia , Biologia Marinha , Extratos Vegetais , RNA Ribossômico 16S/genética , Água do Mar , Metabolismo Secundário , Espanha , Streptomyces/classificação , Streptomyces/isolamento & purificação
20.
Int J Infect Dis ; 49: 59-61, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27263118

RESUMO

OBJECTIVES: Dientamoeba fragilis is a pathogenic protozoan of the human gastrointestinal tract with a worldwide distribution, which has emerged as an important and misdiagnosed cause of chronic gastrointestinal illnesses such as diarrhea and 'irritable-bowel-like' gastrointestinal disease. Very little research has been conducted on the use of suitable antimicrobial compounds. Furthermore, higher rates of co-infection with Enterobius vermicularis have been described, suggesting that E. vermicularis could influence the treatment of D. fragilis-infected patients. To study this, the treatment of E. vermicularis and D. fragilis co-infected patients was evaluated. METHODS: Forty-nine patients with a D. fragilis infection, including 25 (51.0%) patients co-infected with E. vermicularis, were studied. All of them were treated with metronidazole. Patients with E. vermicularis co-infection and/or an E. vermicularis-positive case in the family were treated with mebendazole. RESULTS: Metronidazole treatment failure was significantly more frequent in patients with E. vermicularis co-infection and in patients with children in the family. CONCLUSIONS: Co-infection with E. vermicularis may act as a factor favoring D. fragilis infection by preventing eradication measures. This suggests that both parasites should be treated simultaneously.


Assuntos
Coinfecção/tratamento farmacológico , Dientamoeba/efeitos dos fármacos , Dientamebíase/tratamento farmacológico , Enterobíase/tratamento farmacológico , Enterobius/efeitos dos fármacos , Adolescente , Adulto , Idoso , Animais , Anti-Helmínticos/administração & dosagem , Antiprotozoários , Criança , Pré-Escolar , Coinfecção/parasitologia , Dientamoeba/fisiologia , Dientamebíase/parasitologia , Enterobíase/parasitologia , Enterobius/parasitologia , Fezes/parasitologia , Feminino , Humanos , Masculino , Mebendazol/administração & dosagem , Metronidazol/administração & dosagem , Pessoa de Meia-Idade , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA