Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 63
Filtrar
1.
Biol Sport ; 41(1): 153-161, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38188102

RESUMO

The aims of this study were to: (a) determine the differences in external load quantification between arbitrary and individual speed thresholds over the weekly microcycle in professional soccer players, and (b) analyse the association between internal load and different external load quantification strategies (ELQSs). Ten professional outfield players were monitored during training sessions and official matches using 10 Hz GPS devices over a 6-week in-season period. The absolute and relative ("R" before the distance category) distances covered were calculated for the following external load variables: medium-intensity running distance (MIR), high-intensity running (HIR), sprint distance (SD), and very high-intensity running (VHIR). Individualized thresholds were determined based on maximal sprinting speed (MSS) and the last speed achieved during the 30-15 Intermittent Fitness Test (VIFT) of each player. In terms of match-day workload, significant differences (p < 0.05) were observed between arbitrary and individualized strategies (i.e., MSS and VIFT) for the distance covered in MIR, HIR, SD, VHIR, RHIR, RSD, and RVHIR. The MSS strategy compared to arbitrary thresholds revealed significant differences (p < 0.05) for distance covered in HIR, RHIR, and VHIR during all training sessions. The present results showed that arbitrary thresholds lead to underestimation of external load absolute and relative metrics compared to the MSS strategy throughout the microcycle. The VIFT strategy mainly revealed differences in external load quantification regarding MD compared to arbitrary thresholds. Individualized speed threshold strategies did not achieve better associations with internal load measures in comparison with arbitrary thresholds in professional soccer players.

2.
Mol Cell Proteomics ; 20: 100009, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33214187

RESUMO

The Rhizobium-legume symbiosis is a beneficial interaction in which the bacterium converts atmospheric nitrogen into ammonia and delivers it to the plant in exchange for carbon compounds. This symbiosis implies the adaptation of bacteria to live inside host plant cells. In this work, we apply RP-LC-MS/MS and isobaric tags as relative and absolute quantitation techniques to study the proteomic profile of endosymbiotic cells (bacteroids) induced by Rhizobium leguminosarum bv viciae strain UPM791 in legume nodules. Nitrogenase subunits, tricarboxylic acid cycle enzymes, and stress-response proteins are among the most abundant from over 1000 rhizobial proteins identified in pea (Pisum sativum) bacteroids. Comparative analysis of bacteroids induced in pea and in lentil (Lens culinaris) nodules revealed the existence of a significant host-specific differential response affecting dozens of bacterial proteins, including stress-related proteins, transcriptional regulators, and proteins involved in the carbon and nitrogen metabolisms. A mutant affected in one of these proteins, homologous to a GntR-like transcriptional regulator, showed a symbiotic performance significantly impaired in symbiosis with pea but not with lentil plants. Analysis of the proteomes of bacteroids isolated from both hosts also revealed the presence of different sets of plant-derived nodule-specific cysteine-rich peptides, indicating that the endosymbiotic bacteria find a host-specific cocktail of chemical stressors inside the nodule. By studying variations of the bacterial response to different plant cell environments, we will be able to identify specific limitations imposed by the host that might give us clues for the improvement of rhizobial performance.


Assuntos
Proteínas de Bactérias/metabolismo , Lens (Planta)/microbiologia , Pisum sativum/microbiologia , Rhizobium leguminosarum/metabolismo , Lens (Planta)/genética , Fixação de Nitrogênio , Pisum sativum/genética , Proteínas de Plantas/metabolismo , Proteoma , Rhizobium leguminosarum/genética , Simbiose
3.
J Chem Phys ; 153(2): 024117, 2020 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-32668924

RESUMO

First-principles electronic structure calculations are now accessible to a very large community of users across many disciplines, thanks to many successful software packages, some of which are described in this special issue. The traditional coding paradigm for such packages is monolithic, i.e., regardless of how modular its internal structure may be, the code is built independently from others, essentially from the compiler up, possibly with the exception of linear-algebra and message-passing libraries. This model has endured and been quite successful for decades. The successful evolution of the electronic structure methodology itself, however, has resulted in an increasing complexity and an ever longer list of features expected within all software packages, which implies a growing amount of replication between different packages, not only in the initial coding but, more importantly, every time a code needs to be re-engineered to adapt to the evolution of computer hardware architecture. The Electronic Structure Library (ESL) was initiated by CECAM (the European Centre for Atomic and Molecular Calculations) to catalyze a paradigm shift away from the monolithic model and promote modularization, with the ambition to extract common tasks from electronic structure codes and redesign them as open-source libraries available to everybody. Such libraries include "heavy-duty" ones that have the potential for a high degree of parallelization and adaptation to novel hardware within them, thereby separating the sophisticated computer science aspects of performance optimization and re-engineering from the computational science done by, e.g., physicists and chemists when implementing new ideas. We envisage that this modular paradigm will improve overall coding efficiency and enable specialists (whether they be computer scientists or computational scientists) to use their skills more effectively and will lead to a more dynamic evolution of software in the community as well as lower barriers to entry for new developers. The model comes with new challenges, though. The building and compilation of a code based on many interdependent libraries (and their versions) is a much more complex task than that of a code delivered in a single self-contained package. Here, we describe the state of the ESL, the different libraries it now contains, the short- and mid-term plans for further libraries, and the way the new challenges are faced. The ESL is a community initiative into which several pre-existing codes and their developers have contributed with their software and efforts, from which several codes are already benefiting, and which remains open to the community.

4.
J Stroke Cerebrovasc Dis ; 28(4): 900-905, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30606619

RESUMO

BACKGROUND: Delayed hospital arrival remains the main reason for the low rates of thrombolysis in eligible acute ischemic stroke (AIS) patients. The role of socioeconomic and clinical factors for the prehospital delay of AIS remains poor and has never been studied in Portugal. OBJECTIVES: Describe the socioeconomic and clinical factors leading to delayed hospital admission of AIS patients eligible to thrombolysis. METHODS: A case-control study with a consecutive thrombolyzed AIS patients from 2010 to 2015. Controls were patients who did not receive thrombolysis because of late hospital arrival. Logistic regression with stepwise forward regression analysis was used to identify independent predictors of delayed admission to receive thrombolysis with intravenous tissue-type plasminogen activator (rtPA). RESULTS: Of the 1247 patients admitted with AIS, 76 (6%) arrived on-time and received intravenous rtPA. Controls were 65.8% (146/222) of the total number of patients included in the study. Overall, the mean age was 73 years (±11, 61), a minority were below 60 years, and 43.7% were women. Being beneficiary of social insertion income (odds ratio [OR]: .286; .124-.662, P = .003), not having any telephone contact (OR: .145; .039-.536, .004) or having exclusive landline (.055; .014-.210, <.001) and posterior circulation stroke (OR: .266; .087-.811, P = .020) decreased the likelihood of hospital arrive on-time rtPA. The use of prehospital ambulance services increased (OR: 6.478; 2.751-15.254, P < .001) the odds of ER on-time arrival for thrombolysis. CONCLUSIONS: Poverty, lack of stroke awareness, or difficulties in requesting immediate medical help are the main factors implicated in late-hospital admission for thrombolysis in AIS. Stroke awareness campaigns, promotion of activation of national emergency number and stroke code can increase the rate of thrombolysis.


Assuntos
Fibrinolíticos/administração & dosagem , Admissão do Paciente , Fatores Socioeconômicos , Acidente Vascular Cerebral/tratamento farmacológico , Terapia Trombolítica/métodos , Tempo para o Tratamento , Ativador de Plasminogênio Tecidual/administração & dosagem , Transporte de Pacientes , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Acessibilidade aos Serviços de Saúde , Humanos , Infusões Intravenosas , Masculino , Pessoa de Meia-Idade , Portugal , Pobreza , Medição de Risco , Fatores de Risco , Serviços de Saúde Rural , Acidente Vascular Cerebral/diagnóstico , Fatores de Tempo , Resultado do Tratamento
5.
Appl Environ Microbiol ; 83(6)2017 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-28062461

RESUMO

The genetic diversity of bacterial populations nodulating Lupinus micranthus in five geographical sites from northern Tunisia was examined. Phylogenetic analyses of 50 isolates based on partial sequences of recA and gyrB grouped strains into seven clusters, five of which belong to the genus Bradyrhizobium (28 isolates), one to Phyllobacterium (2 isolates), and one, remarkably, to Microvirga (20 isolates). The largest Bradyrhizobium cluster (17 isolates) grouped with the B. lupini species, and the other five clusters were close to different recently defined Bradyrhizobium species. Isolates close to Microvirga were obtained from nodules of plants from four of the five sites sampled. We carried out an in-depth phylogenetic study with representatives of the seven clusters using sequences from housekeeping genes (rrs, recA, glnII, gyrB, and dnaK) and obtained consistent results. A phylogeny based on the sequence of the symbiotic gene nodC identified four groups, three formed by Bradyrhizobium isolates and one by the Microvirga and Phyllobacterium isolates. Symbiotic behaviors of the representative strains were tested, and some congruence between symbiovars and symbiotic performance was observed. These data indicate a remarkable diversity of L. micranthus root nodule symbionts in northern Tunisia, including strains from the Bradyrhizobiaceae, Methylobacteriaceae, and Phyllobacteriaceae families, in contrast with those of the rhizobial populations nodulating lupines in the Old World, including L. micranthus from other Mediterranean areas, which are nodulated mostly by Bradyrhizobium strains.IMPORTANCELupinus micranthus is a legume broadly distributed in the Mediterranean region and plays an important role in soil fertility and vegetation coverage by fixing nitrogen and solubilizing phosphate in semiarid areas. Direct sowing to extend the distribution of this indigenous legume can contribute to the prevention of soil erosion in pre-Saharan lands of Tunisia. However, rhizobial populations associated with L. micranthus are poorly understood. In this context, the diversity of endosymbionts of this legume was investigated. Most Lupinus species are nodulated by Bradyrhizobium strains. This work showed that about half of the isolates from northern Tunisian soils were in fact Bradyrhizobium symbionts, but the other half were found unexpectedly to be bacteria within the genera Microvirga and Phyllobacterium These unusual endosymbionts may have a great ecological relevance. Inoculation with the appropriate selected symbiotic bacterial partners will increase L. micranthus survival with consequent advantages for the environment in semiarid areas of Tunisia.


Assuntos
Bradyrhizobium/isolamento & purificação , Lupinus/microbiologia , Methylobacteriaceae/isolamento & purificação , Phyllobacteriaceae/isolamento & purificação , Nódulos Radiculares de Plantas/microbiologia , Biodiversidade , Bradyrhizobium/classificação , Bradyrhizobium/genética , DNA Girase/genética , DNA Bacteriano/genética , Genes Essenciais/genética , Methylobacteriaceae/classificação , Methylobacteriaceae/genética , Phyllobacteriaceae/classificação , Phyllobacteriaceae/genética , Filogenia , Nodulação/fisiologia , RNA Ribossômico 16S/genética , Recombinases Rec A/genética , Microbiologia do Solo , Simbiose/fisiologia , Tunísia
6.
Angew Chem Int Ed Engl ; 54(13): 3917-21, 2015 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-25651288

RESUMO

Water dissociation is crucial in many catalytic reactions on oxide-supported transition-metal catalysts. Supported by experimental and density-functional theory results, the effect of the support on OH bond cleavage activity is elucidated for nickel/ceria systems. Ambient-pressure O 1s photoemission spectra at low Ni loadings on CeO2 (111) reveal a substantially larger amount of OH groups as compared to the bare support. Computed activation energy barriers for water dissociation show an enhanced reactivity of Ni adatoms on CeO2 (111) compared with pyramidal Ni4 particles with one Ni atom not in contact with the support, and extended Ni(111) surfaces. At the origin of this support effect is the ability of ceria to stabilize oxidized Ni(2+) species by accommodating electrons in localized f-states. The fast dissociation of water on Ni/CeO2 has a dramatic effect on the activity and stability of this system as a catalyst for the water-gas shift and ethanol steam reforming reactions.

7.
Int J Syst Evol Microbiol ; 64(Pt 6): 2072-2078, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24664579

RESUMO

A group of strains isolated from root nodules of Phaseolus lunatus (Lima bean) in Peru were characterized by genotypic, genomic and phenotypic methods. All strains possessed identical 16S rRNA gene sequences that were 99.9% identical to that of Bradyrhizobium lablabi CCBAU 23086(T). Despite having identical 16S rRNA gene sequences, the Phaseolus lunatus strains could be divided into two clades by sequence analysis of recA, atpD, glnII, dnaK and gyrB genes. The genome sequence of a representative of each clade was obtained and compared to the genomes of closely related species of the genus Bradyrhizobium. Average nucleotide identity values below the species circumscription threshold were obtained when comparing the two clades to each other (88.6%) and with all type strains of the genus Bradyrhizobium (≤92.9%). Phenotypes distinguishing both clades from all described and closely related species of the genus Bradyrhizobium were found. On the basis of the results obtained, two novel species, Bradyrhizobium paxllaeri sp. nov. (type strain LMTR 21(T) = DSM 18454(T) = HAMBI 2911(T)) and Bradyrhizobium icense sp. nov. (type strain LMTR 13(T) = HAMBI 3584(T) = CECT 8509(T) = CNPSo 2583(T)), are proposed to accommodate the uncovered clades of Phaseolus lunatus bradyrhizobia. These species share highly related but distinct nifH and nodC symbiosis genes.


Assuntos
Bradyrhizobium/classificação , Phaseolus/microbiologia , Filogenia , Nódulos Radiculares de Plantas/metabolismo , Técnicas de Tipagem Bacteriana , Composição de Bases , Bradyrhizobium/genética , Bradyrhizobium/isolamento & purificação , DNA Bacteriano/genética , Ácidos Graxos/química , Genes Bacterianos , Dados de Sequência Molecular , Fixação de Nitrogênio , Hibridização de Ácido Nucleico , Peru , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Simbiose
8.
Antonie Van Leeuwenhoek ; 105(6): 1121-9, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24756908

RESUMO

Fifty-one rhizobial strains isolated from root nodules of Cytisus villosus growing in Northeastern Algeria were characterized by genomic and phenotypic analyses. Isolates were grouped into sixteen different patterns by PCR-RAPD. The phylogenetic status of one representative isolate from each pattern was examined by multilocus sequence analyses of four housekeeping genes (16S rRNA, glnII, recA, and atpD) and one symbiotic gene (nodC). Analysis of 16S rRNA gene sequences showed that all the isolates belonged to the genus Bradyrhizobium. Phylogenetic analyses based on individual or concatenated genes glnII, recA, and atpD indicated that strains cluster in three distinct groups. Ten out of the sixteen strains grouped together with Bradyrhizobium japonicum, while a second group of four clustered with Bradyrhizobium canariense. The third group, represented by isolates CTS8 and CTS57, differed significantly from all other bradyrhizobia known to nodulate members of the Genisteae tribe. In contrast with core genes, sequences of the nodC symbiotic gene from all the examined strains form a homogeneous group within the genistearum symbiovar of Bradyrhizobium. All strains tested nodulated Lupinus angustifolius, Lupinus luteus, and Spartium junceum but not Glycine max. From these results, it is concluded that C. villosus CTS8 and CTS57 strains represent a new lineage within the Bradyrhizobium genus.


Assuntos
Bradyrhizobium/classificação , Bradyrhizobium/isolamento & purificação , Cytisus/microbiologia , Cytisus/fisiologia , Nodulação , Argélia , Proteínas de Bactérias/genética , Bradyrhizobium/genética , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Genes Bacterianos , Lupinus/microbiologia , Lupinus/fisiologia , Dados de Sequência Molecular , Tipagem de Sequências Multilocus , Filogenia , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/genética , Técnica de Amplificação ao Acaso de DNA Polimórfico , Spartium/microbiologia , Spartium/fisiologia
9.
Front Microbiol ; 15: 1341728, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38333580

RESUMO

Regulating the transition of bacteria from motile to sessile lifestyles is crucial for their ability to compete effectively in the rhizosphere environment. Pseudomonas are known to rely on extracellular matrix (ECM) components for microcolony and biofilm formation, allowing them to adapt to a sessile lifestyle. Pseudomonas ogarae F113 possesses eight gene clusters responsible for the production of ECM components. These gene clusters are tightly regulated by AmrZ, a major transcriptional regulator that influences the cellular levels of c-di-GMP. The AmrZ-mediated transcriptional regulation of ECM components is primarily mediated by the signaling molecule c-di-GMP and the flagella master regulator FleQ. To investigate the functional role of these ECM components in P. ogarae F113, we performed phenotypic analyses using mutants in genes encoding these ECM components. These analyses included assessments of colony morphology, dye-staining, static attachment to abiotic surfaces, dynamic biofilm formation on abiotic surfaces, swimming motility, and competitive colonization assays of the rhizosphere. Our results revealed that alginate and PNAG polysaccharides, along with PsmE and the fimbrial low molecular weight protein/tight adherence (Flp/Tad) pilus, are the major ECM components contributing to biofilm formation. Additionally, we found that the majority of these components and MapA are needed for a competitive colonization of the rhizosphere in P. ogarae F113.

10.
Artigo em Inglês | MEDLINE | ID: mdl-38517632

RESUMO

The biodegradation of total petroleum hydrocarbon (TPH) in soil is very challenging due to the complex recalcitrant nature of hydrocarbon, hydrophobicity, indigenous microbial adaptation and competition, and harsh environmental conditions. This work further confirmed that limited natural attenuation of petroleum hydrocarbons (TPHs) (15% removal) necessitates efficient bioremediation strategies. Hence, a scaling-up experiment for testing and optimizing the use of biopiles for bioremediation of TPH polluted soils was conducted with three 500-kg pilots of polluted soil, and respective treatments were implemented: including control soil (CT), bioaugmentation and vermicompost treatment (BAVC), and a combined application of BAVC along with bioelectrochemical snorkels (BESBAVC), all maintained at 40% field capacity. This study identified that at pilot scale level, a successful application of BAVC treatment can achieve 90.3% TPH removal after 90 days. BAVC's effectiveness stemmed from synergistic mechanisms. Introduced microbial consortia were capable of TPH degradation, while vermicompost provided essential nutrients, enhanced aeration, and, potentially, acted as a biosorbent. Hence, it can be concluded that the combined application of BAVC significantly enhances TPH removal compared to natural attenuation. While the combined application of a bioelectrochemical snorkel (BES) with BAVC also showed a significant TPH removal, it did not differ statistically from the individual application of BAVC, under applied conditions. Further research is needed to optimize BES integration with BAVC for broader applicability. This study demonstrates BAVC as a scalable and mechanistically sound approach for TPH bioremediation in soil.

11.
J Orthop Traumatol ; 14(1): 39-49, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23160803

RESUMO

BACKGROUND: The preoperative bone defect and the reconstruction of the center of rotation of the hip are critical in acetabular revision surgery. Uncemented oblong cups are employed in order to manage these issues. We analyzed the clinical results and rates of revision of two different uncemented oblong cups, the reconstruction of the center of rotation of the hip, as well as the rate of radiological loosening and possible risk factors. MATERIALS AND METHODS: Forty-five patients (46 hips) underwent acetabular revision surgery using two different uncemented oblong cups. We assessed the clinical results and the survival rate for revision and aseptic loosening. Intraoperative bone loss was classified according to Paprosky, and acetabular reconstruction was assessed according to Ranawat. The mean follow-up was 7.2 years (range 4-11 years). RESULTS: There were four re-revisions (three due to aseptic loosening); the survival rate for re-revision due to aseptic loosening was 60.1 % at seven years. The mean distance between the center of the femoral head prosthesis and the approximate center of the femoral head improved from 21.5 to 10.2 mm. Thirteen cups showed radiological loosening; the survival rate for radiological loosening at seven years was 40.54 %. A smaller postoperative horizontal distance was correlated with cup loosening. CONCLUSIONS: Although optimal acetabular reconstruction can be achieved by using oblong uncemented cups in revision hip surgery, the clinical and radiological results are not encouraging. Excessive medialization of the cup may increase the rate of loosening.


Assuntos
Artroplastia de Quadril/instrumentação , Prótese Articular , Desenho de Prótese , Adulto , Idoso , Idoso de 80 Anos ou mais , Artroplastia de Quadril/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Falha de Prótese , Procedimentos de Cirurgia Plástica/instrumentação , Procedimentos de Cirurgia Plástica/métodos , Reoperação , Fatores de Risco
12.
Microorganisms ; 11(4)2023 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-37110460

RESUMO

Motility and biofilm formation are two crucial traits in the process of rhizosphere colonization by pseudomonads. The regulation of both traits requires a complex signaling network that is coordinated by the AmrZ-FleQ hub. In this review, we describe the role of this hub in the adaption to the rhizosphere. The study of the direct regulon of AmrZ and the phenotypic analyses of an amrZ mutant in Pseudomonas ogarae F113 has shown that this protein plays a crucial role in the regulation of several cellular functions, including motility, biofilm formation, iron homeostasis, and bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) turnover, controlling the synthesis of extracellular matrix components. On the other hand, FleQ is the master regulator of flagellar synthesis in P. ogarae F113 and other pseudomonads, but its implication in the regulation of multiple traits related with environmental adaption has been shown. Genomic scale studies (ChIP-Seq and RNA-Seq) have shown that in P. ogarae F113, AmrZ and FleQ are general transcription factors that regulate multiple traits. It has also been shown that there is a common regulon shared by the two transcription factors. Moreover, these studies have shown that AmrZ and FleQ form a regulatory hub that inversely regulate traits such as motility, extracellular matrix component production, and iron homeostasis. The messenger molecule c-di-GMP plays an essential role in this hub since its production is regulated by AmrZ and it is sensed by FleQ and required for its regulatory role. This regulatory hub is functional both in culture and in the rhizosphere, indicating that the AmrZ-FleQ hub is a main player of P. ogarae F113 adaption to the rhizosphere environment.

13.
Genes (Basel) ; 14(11)2023 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-38002922

RESUMO

The model rhizobacterium Pseudomonas ogarae F113, a relevant plant growth-promoting bacterium, encodes three different Type VI secretion systems (T6SS) in its genome. In silico analysis of its genome revealed the presence of a genetic auxiliary module containing a gene encoding an orphan VgrG protein (VgrG5a) that is not genetically linked to any T6SS structural cluster, but is associated with genes encoding putative T6SS-related proteins: a possible adaptor Tap protein, followed by a putative effector, Tfe8, and its putative cognate immunity protein, Tfi8. The bioinformatic analysis of the VgrG5a auxiliary module has revealed that this cluster is only present in several subgroups of the P. fluorescens complex of species. An analysis of the mutants affecting the vgrG5a and tfe8 genes has shown that the module is involved in bacterial killing. To test whether Tfe8/Tfi8 constitute an effector-immunity pair, the genes encoding Tfe8 and Tfi8 were cloned and expressed in E. coli, showing that the ectopic expression of tfe8 affected growth. The growth defect was suppressed by tfi8 ectopic expression. These results indicate that Tfe8 is a bacterial killing effector, while Tfi8 is its cognate immunity protein. The Tfe8 protein sequence presents homology to the proteins of the MATE family involved in drug extrusion. The Tfe8 effector is a membrane protein with 10 to 12 transmembrane domains that could destabilize the membranes of target cells by the formation of pores, revealing the importance of these effectors for bacterial interaction. Tfe8 represents a novel type of a T6SS effector present in pseudomonads.


Assuntos
Sistemas de Secreção Tipo VI , Sistemas de Secreção Tipo VI/genética , Sistemas de Secreção Tipo VI/metabolismo , Escherichia coli/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sequência de Aminoácidos , Pseudomonas/genética , Pseudomonas/metabolismo
14.
Front Microbiol ; 14: 1158130, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37152743

RESUMO

Ecopiling is a method for biodegradation of hydrocarbons in soils. It derives from Biopiles, but phytoremediation is added to biostimulation with nitrogen fertilization and bioaugmentation with local bacteria. We have constructed seven Ecopiles with soil heavily polluted with hydrocarbons in Carlow (Ireland). The aim of the study was to analyze changes in the microbial community during ecopiling. In the course of 18 months of remediation, total petroleum hydrocarbons values decreased in 99 and 88% on average for aliphatics and aromatics, respectively, indicating a successful biodegradation. Community analysis showed that bacterial alfa diversity (Shannon Index), increased with the degradation of hydrocarbons, starting at an average value of 7.59 and ending at an average value of 9.38. Beta-diversity analysis, was performed using Bray-Curtis distances and PCoA ordination, where the two first principal components (PCs) explain the 17 and 14% of the observed variance, respectively. The results show that samples tend to cluster by sampling time instead of by Ecopile. This pattern is supported by the hierarchical clustering analysis, where most samples from the same timepoint clustered together. We used DSeq2 to determine the differential abundance of bacterial populations in Ecopiles at the beginning and the end of the treatment. While TPHs degraders are more abundant at the start of the experiment, these populations are substituted by bacterial populations typical of clean soils by the end of the biodegradation process. Similar results are found for the fungal community, indicating that the microbial community follows a succession along the process. This succession starts with a TPH degraders or tolerant enriched community, and finish with a microbial community typical of clean soils.

15.
J Phys Chem A ; 116(10): 2394-404, 2012 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-22320704

RESUMO

A new full-dimension potential energy surface of the three-body He-Rb2(³Σ(u)(+)) complex and a quantum study of small (4He)(N)-Rb2(³Σ(u)(+)) clusters, 1 ≤ N ≤ 4, are presented. We have accurately fitted the ab initio points of the interaction to an analytical form and addressed the dopant's vibration, which is found to be negligible. A Variational approach and a Diffusion Monte Carlo technique have been applied to yield energy and geometric properties of the selected species. Our quantum structure calculations show a transition in the arrangements of the helium atoms from N = 2, where they tend to be separated across the diatomic bond, to N = 4, in which a closer packing of the rare gas particles is reached, guided by the dominance of the He-He potential over the weaker interaction of the latter adatoms with the doping dimer. The deepest well of the He-Rb2 interaction is placed at the T-shape configuration, a feature which causes the dopant to be located as parallel to the helium "minidroplet". Our results are shown to agree with previous findings on this and on similar systems.

16.
Posit Aware ; 29(1): 40-1, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29505210
17.
Microb Genom ; 8(1)2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-35012704

RESUMO

Rhizosphere colonization by bacteria involves molecular and cellular mechanisms, such as motility and chemotaxis, biofilm formation, metabolic versatility, or biosynthesis of secondary metabolites, among others. Nonetheless, there is limited knowledge concerning the main regulatory factors that drive the rhizosphere colonization process. Here we show the importance of the AmrZ and FleQ transcription factors for adaption in the plant growth-promoting rhizobacterium (PGPR) and rhizosphere colonization model Pseudomonas ogarae F113. RNA-Seq analyses of P. ogarae F113 grown in liquid cultures either in exponential and stationary growth phase, and rhizosphere conditions, revealed that rhizosphere is a key driver of global changes in gene expression in this bacterium. Regarding the genetic background, this work has revealed that a mutation in fleQ causes considerably more alterations in the gene expression profile of this bacterium than a mutation in amrZ under rhizosphere conditions. The functional analysis has revealed that in P. ogarae F113, the transcription factors AmrZ and FleQ regulate genes involved in diverse bacterial functions. Notably, in the rhizosphere, these transcription factors antagonistically regulate genes related to motility, biofilm formation, nitrogen, sulfur, and amino acid metabolism, transport, signalling, and secretion, especially the type VI secretion systems. These results define the regulon of two important bifunctional transcriptional regulators in pseudomonads during the process of rhizosphere colonization.


Assuntos
Perfilação da Expressão Gênica/métodos , Redes Reguladoras de Genes , Pseudomonas/crescimento & desenvolvimento , Fatores de Transcrição/genética , Adaptação Fisiológica , Proteínas de Bactérias/genética , Regulação Bacteriana da Expressão Gênica , Medicago sativa/crescimento & desenvolvimento , Mutação , Pseudomonas/genética , RNA-Seq , Rizosfera
18.
Sci Rep ; 12(1): 11914, 2022 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-35831472

RESUMO

The AmrZ/FleQ hub has been identified as a central node in the regulation of environmental adaption in the plant growth-promoting rhizobacterium and model for rhizosphere colonization Pseudomonas ogarae F113. AmrZ is involved in the regulation of motility, biofilm formation, and bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) turnover, among others, in this bacterium. The mutants in amrZ have a pleiotropic phenotype with distinguishable colony morphology, reduced biofilm formation, increased motility, and are severely impaired in competitive rhizosphere colonization. Here, RNA-Seq and qRT-PCR gene expression analyses revealed that AmrZ regulates many genes related to the production of extracellular matrix (ECM) components at the transcriptional level. Furthermore, overproduction of c-di-GMP in an amrZ mutant, by ectopic production of the Caulobacter crescentus constitutive diguanylate cyclase PleD*, resulted in increased expression of many genes implicated in the synthesis of ECM components. The overproduction of c-di-GMP in the amrZ mutant also suppressed the biofilm formation and motility phenotypes, but not the defect in competitive rhizosphere colonization. These results indicate that although biofilm formation and motility are mainly regulated indirectly by AmrZ, through the modulation of c-di-GMP levels, the implication of AmrZ in rhizosphere competitive colonization occurs in a c-di-GMP-independent manner.


Assuntos
Regulação Bacteriana da Expressão Gênica , Pseudomonas , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biofilmes , GMP Cíclico/análogos & derivados , GMP Cíclico/metabolismo , Matriz Extracelular/metabolismo , Pseudomonas/genética , Pseudomonas/metabolismo
19.
Diagnostics (Basel) ; 12(10)2022 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-36292051

RESUMO

Osteoarthritis (OA) affects nearly 240 million people worldwide. Knee OA is the most common type of arthritis, especially in older adults. Physicians measure the severity of knee OA according to the Kellgren and Lawrence (KL) scale through visual inspection of X-ray or MR images. We propose a semi-automatic CADx model based on Deep Siamese convolutional neural networks and a fine-tuned ResNet-34 to simultaneously detect OA lesions in the two knees according to the KL scale. The training was done using a public dataset, whereas the validations were performed with a private dataset. Some problems of the imbalanced dataset were solved using transfer learning. The model results average of the multi-class accuracy is 61%, presenting better performance results for classifying classes KL-0, KL-3, and KL-4 than KL-1 and KL-2. The classification results were compared and validated using the classification of experienced radiologists.

20.
J Phys Chem A ; 115(25): 6892-902, 2011 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-21585200

RESUMO

We present in this work the study of small (4)He(N)-Cs(2)((3)Σ(u)) aggregates (2 ≤ N ≤ 30) through combined variational, diffusion Monte Carlo (DMC), and path integral Monte Carlo (PIMC) calculations. The full surface is modeled as an addition of He-Cs(2) interactions and He-He potentials. Given the negligible strength and large range of the He-Cs(2) interaction as compared with the one for He-He, a propensity of the helium atoms to pack themselves together, leaving outside the molecular dopant is to be expected. DMC calculations determine the onset of helium gathering at N = 3. To analyze energetic and structural properties as a function of N, PIMC calculations with no bosonic exchange, i.e., Boltzmann statistics, at low temperatures are carried out. At T = 0.1 K, although acceptable one-particle He-Cs(2) distributions are obtained, two-particle He-He distributions are not well described, indicating that the proper symmetry should be taken into account. PIMC distributions at T = 1 K already compare well with DMC ones and show minor exchange effects, although binding energies are still far from having converged in terms of the number of quantum beads. As N increases, the He-He PIMC pair correlation function shows a clear tendency to coincide with the experimental boson-liquid helium one at that temperature. It supports the picture of a helium droplet which carries the molecular impurity on its surface, as found earlier for other triplet dimers.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA