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1.
Wellcome Open Res ; 9: 154, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39246513

RESUMO

Background: Rennes, a midsize city in France, features many opportunities for active travel. City officials seek to increase walking and cycling by 2030 to improve public health. Physical inactivity, a leading risk factor for premature mortality around the globe, has been shown to be associated with many chronic diseases including heart disease, type 2 diabetes, and cancer. Methods: Using the 2018 household travel survey of Rennes residents, we apply the Health-Oriented Transportation statistical model to assess health impacts associated with population-level rates of walking and cycling. We consider two proposed mobility and climate objectives which outline sustainable transportation goals by 2030. These include a shift in transportation mode share to increase walking and cycling trips, as well as a broad reduction in vehicle miles traveled (VMT) across the metropolitan area. Results: Our regression analysis demonstrated that factors of household car access and inner-city residency were predictors of prevalence (observed one-day proportion engaging in walking or cycling), participation (weekly proportion), and intensity (mean individual physical activity achieved through walking/cycling) of active travel. Age and education were additionally associated with prevalence. The 2030 mobility objective (mode share: 9% cycle, 35% walk) was associated with a reduction of 1,051 DALYs (disability-adjusted life-years), translating to $73 million USD ($23-$177) in averted costs. The climate objective (10% reduction in VMT) was associated with a reduction of 369 DALYs when replaced entirely by walking and 714 DALYs with cycling, translating to $26 million ($8-$62) and $50 million ($15-$121) saved, respectively. Conclusions: Rennes residents experience high participation in active travel, particularly those in the inner city. If residents achieve the city's active travel goals for 2030, there is potential for a large reduction in health burden and subsequent costs. Reaching these goals may require significant investment in transportation programming and infrastructure to improve active travel opportunities.

2.
Glob Health Promot ; : 17579759241238009, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38716682

RESUMO

Sustainable development goals (SDGs) and public health are often considered as separate policy fields, whereas there is a considerable potential in better coordinating their objectives and measures. Using an analytical grid (S2D grid) linking SDGs and public health objectives and comprising 6 thematic issues and 56 categories, the research team conducted an assessment of health promotion programs in the city of Lausanne, Switzerland. Their objective was to determine whether SDGs and public health concerns can translate into complementary policy objectives, and what was the level of achievement of Lausanne in terms of implementation, intersectoral collaboration and avoidance of redundancy, regarding the vast array of measures potentially dealing with SDGs and health promotion. Results show that measures implemented by Lausanne deal with 80% of categories included in the S2D grid, with a high level of intersectorality and a low level of redundancy. These results also emphasize the fact that linkages between SDGs and health promotion go well beyond the SDG 3 dedicated to 'good health and well-being', and that the S2D grid could be used as a tool in favor of organizational change, promoting the collaboration between stakeholders often reluctant to engage in public health policies.

3.
Wellcome Open Res ; 6: 35, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34095507

RESUMO

Background: Environmental improvement is a priority for urban sustainability and health and achieving it requires transformative change in cities. An approach to achieving such change is to bring together researchers, decision-makers, and public groups in the creation of research and use of scientific evidence. Methods: This article describes the development of a programme theory for Complex Urban Systems for Sustainability and Health (CUSSH), a four-year Wellcome-funded research collaboration which aims to improve capacity to guide transformational health and environmental changes in cities. Results: Drawing on ideas about complex systems, programme evaluation, and transdisciplinary learning, we describe how the programme is understood to "work" in terms of its anticipated processes and resulting changes. The programme theory describes a chain of outputs that ultimately leads to improvement in city sustainability and health (described in an 'action model'), and the kinds of changes that we expect CUSSH should lead to in people, processes, policies, practices, and research (described in a 'change model'). Conclusions: Our paper adds to a growing body of research on the process of developing a comprehensive understanding of a transdisciplinary, multiagency, multi-context programme. The programme theory was developed collaboratively over two years. It involved a participatory process to ensure that a broad range of perspectives were included, to contribute to shared understanding across a multidisciplinary team. Examining our approach allowed an appreciation of the benefits and challenges of developing a programme theory for a complex, transdisciplinary research collaboration. Benefits included the development of teamworking and shared understanding and the use of programme theory in guiding evaluation. Challenges included changing membership within a large group, reaching agreement on what the theory would be 'about', and the inherent unpredictability of complex initiatives.

4.
Artigo em Inglês | MEDLINE | ID: mdl-33670207

RESUMO

This scoping study aims to explore the relationships between urban green spaces (UGSs) and the onset, remission and recovery of cancer. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping reviews (protocol published in 2018). Eligibility criteria for papers were: (1) to be concerned with UGSs, (2) reporting effects of UGSs on cancer-related outcomes including direct or indirect measures, (3) reporting randomized controlled trials, prospective cohort studies, case studies, observational studies, non-comparative studies, (4) in English or French. The search covered primary studies in the published and unpublished (grey) literatures searching by hand and electronic databases (MEDLINE, Green File, Cumulative Index to Nursing and Allied Health Literature and ScienceDirect). Among 1703 records screened by two reviewers independently, 29 were included for qualitative synthesis. We classify the cancers concerned and the effects reported i.e., protective effect, risk or without association. The most investigated cancers are bladder, breast and lung cancer. Our study also identified contributing factors and their mediating effects between UGSs and cancer. Even though the strength of the evidence of the associations between UGSs and cancer is still weak due to the low number of studies and their design, results highlight the wide variety of possible mediating factors between the use of green spaces and cancer occurrence, remission and/or prevention. Knowledge gaps and future research perspectives should be oriented to qualitative research on protective factors with an attention to equity in UGS access and use.


Assuntos
Neoplasias , Parques Recreativos , Humanos , Neoplasias/epidemiologia , Estudos Prospectivos , Pesquisa Qualitativa
5.
BMJ Open ; 10(9): e034667, 2020 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-32988936

RESUMO

INTRODUCTION: Scientists from a wide variety of fields of knowledge are increasingly interested in climate change issues. The importance given to the phenomenon is explained by the uncertainties surrounding it and its consequences not yet fully known. However, there is wide agreement that human activities are modifying the Earth's climate beyond the natural cyclical changes and that these changes impact human health. This scoping review aimed to understand how research on the links between climate change and human health in urban areas is conducted and how this research is approached holistically or not. METHODS AND ANALYSIS: This scoping review is mainly guided by the Arskey and O'Malley scoping review framework. A broad range of databases will be used, including PubMed, ScienceDirect, Web of Science Core Collection, GreenFILE and Information Science & Technology Abstracts. Predefined inclusion and exclusion criteria will be used, with a focus on climate change and human health outcome studies published between January 1990 and July 2019. An interdisciplinary team has formulated search strategies and the reviewers will independently screen eligible studies for final study selection. We will apply a thematic analysis to evaluate and categorise the study findings. We expect to map the research according to the scientific research methods, the scientific fields and the determinants of health studied. Along these lines, we will be able to understand how holistic the research is. ETHICS AND DISSEMINATION: No primary data will be collected since all data presented in this review are based on published articles and publicly available documents. Therefore, ethics committee approval is not a requirement. The findings will be disseminated through publication in a peer-reviewed journal, presentations at conferences relevant to the field of this research, as well as presentations to relevant stakeholders.


Assuntos
Mudança Climática , Atenção à Saúde , Humanos , Revisão por Pares , Projetos de Pesquisa
6.
Dis Model Mech ; 12(7)2019 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-31213478

RESUMO

Damage to cochlear primary afferent synapses has been shown to be a key factor in various auditory pathologies. Similarly, the selective lesioning of primary vestibular synapses might be an underlying cause of peripheral vestibulopathies that cause vertigo and dizziness, for which the pathophysiology is currently unknown. To thoroughly address this possibility, we selectively damaged the synaptic contacts between hair cells and primary vestibular neurons in mice through the transtympanic administration of a glutamate receptor agonist. Using a combination of histological and functional approaches, we demonstrated four key findings: (1) selective synaptic deafferentation is sufficient to generate acute vestibular syndrome with characteristics similar to those reported in patients; (2) the reduction of the vestibulo-ocular reflex and posturo-locomotor deficits mainly depends on spared synapses; (3) damaged primary vestibular synapses can be repaired over the days and weeks following deafferentation; and (4) the synaptic repair process occurs through the re-expression and re-pairing of synaptic proteins such as CtBP2 and SHANK-1. Primary synapse repair might contribute to re-establishing the initial sensory network. Deciphering the molecular mechanism that supports synaptic repair could offer a therapeutic opportunity to rescue full vestibular input and restore gait and balance in patients.


Assuntos
Vias Aferentes/fisiologia , Sinapses/fisiologia , Vertigem/fisiopatologia , Animais , Modelos Animais de Doenças , Camundongos
7.
Artigo em Inglês | MEDLINE | ID: mdl-30292730

RESUMO

The discipline of affective neuroscience is concerned with the neural bases of emotion and mood. The past decades have witnessed an explosion of research in affective neuroscience, increasing our knowledge of the brain areas involved in fear and anxiety. Besides the brain areas that are classically associated with emotional reactivity, accumulating evidence indicates that both the vestibular and cerebellar systems are involved not only in motor coordination but also influence both cognition and emotional regulation in humans and animal models. The cerebellar and the vestibular systems show the reciprocal connection with a myriad of anxiety and fear brain areas. Perception anticipation and action are also major centers of interest in cognitive neurosciences. The cerebellum is crucial for the development of an internal model of action and the vestibular system is relevant for perception, gravity-related balance, navigation and motor decision-making. Furthermore, there are close relationships between these two systems. With regard to the cooperation between the vestibular and cerebellar systems for the elaboration and the coordination of emotional cognitive and visceral responses, we propose that altering the function of one of the systems could provoke internal model disturbances and, as a result, anxiety disorders followed potentially with depressive states.


Assuntos
Transtornos de Ansiedade/fisiopatologia , Cerebelo/fisiopatologia , Transtorno Depressivo/fisiopatologia , Núcleos Vestibulares/fisiopatologia , Animais , Humanos , Vias Neurais/fisiopatologia
8.
Sleep Med Rev ; 42: 220-228, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30293919

RESUMO

The vestibular system encodes linear and angular head motion supporting numerous functions from gaze stabilization and postural control, to high-level cortical functions involving spatial cognition, including self-body perception, verticality perception, orientation, navigation and spatial memory. At the brainstem and mesencephalic levels, the vestibular organs also influence postural blood pressure regulation, bone density and muscle composition via specific vestibulo-sympathetic efferences and have been shown to act as a powerful synchronizer of circadian rhythms. Here, we review the evidence that sleep deprivation and sleep apnea syndrome alter vestibular-related oculo-motor and postural control, and that, in turn, vestibular pathologies induce sleep disturbances. We suggest that sleep-related neuroplasticity might serve the adaptation and compensation processes following vestibular lesions in patients. Interestingly, a reciprocal neuroanatomical route between the vestibular nuclei and the orexinergic neurons has been reported. While orexinergic modulation of the vestibular nuclei related to postural control has been suggested, we postulate that vestibular inputs might in turn influence the sleep-wake state switch, informing the brain about the daily quantity of motion.


Assuntos
Síndromes da Apneia do Sono/fisiopatologia , Sono/fisiologia , Vestíbulo do Labirinto , Encéfalo , Humanos , Plasticidade Neuronal
9.
Neurosci Lett ; 683: 43-47, 2018 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-29936267

RESUMO

There is substantial evidence that loss of vestibular function impairs spatial learning and memory related to hippocampal (HPC) function, as well as increasing evidence that striatal (Str) plasticity is also implicated. Since the N-methyl-d-aspartate (NMDA) subtype of glutamate receptor is considered essential to spatial memory, previous studies have investigated whether the expression of HPC NMDA receptors changes following vestibular loss; however, the results have been contradictory. Here we used a novel flow cytometric method to quantify the number of neurons expressing NMDA receptors in the HPC and Str following bilateral vestibular loss (BVL) in rats. At 7 and 30 days post-op., there was a significant increase in the number of HPC neurons expressing NMDA receptors in the BVL animals, compared to sham controls (P ≤ 0.004 and P ≤ 0.0001, respectively). By contrast, in the Str, at 7 days there was a significant reduction in the number of neurons expressing NMDA receptors in the BVL group (P ≤ 0.05); however, this difference had disappeared by 30 days post-op. These results suggest that BVL causes differential changes in the number of neurons expressing NMDA receptors in the HPC and Str, which may be related to its long-term impairment of spatial memory.


Assuntos
Corpo Estriado/metabolismo , Citometria de Fluxo/métodos , Hipocampo/metabolismo , Neurônios/metabolismo , Receptores de N-Metil-D-Aspartato/biossíntese , Vestíbulo do Labirinto/metabolismo , Animais , Corpo Estriado/citologia , Orelha Interna/citologia , Orelha Interna/metabolismo , Orelha Interna/cirurgia , Expressão Gênica , Hipocampo/citologia , Masculino , Ratos , Ratos Sprague-Dawley , Receptores de N-Metil-D-Aspartato/genética , Vestíbulo do Labirinto/citologia , Vestíbulo do Labirinto/cirurgia
10.
BMJ Open ; 8(2): e018851, 2018 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-29453298

RESUMO

INTRODUCTION: Green space in the built environment is an important topic on the health agenda today. Studies have shown that access to green spaces is associated with better mental and physical health, yet green spaces can also be detrimental to health if they are not managed appropriately. Despite the increasing interest in urban green spaces, little research has so far been conducted into the links between green spaces and cancer. OBJECTIVE: The purpose of this scoping review is therefore to map the literature available on the types of relationship between urban green spaces and cancer. METHOD AND ANALYSIS: We followed the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols 2015 guideline to report the protocol. To conduct this scoping review, we will use a structured search strategy based on controlled vocabulary and relevant key terms related to green space, urban space and cancer. We will search MEDLINE (PubMed), GreenFILE (EBSCOhost), Cumulative Index to Nursing and Allied Health Literature (EBSCOhost) and ScienceDirect as electronic database as well as hand-search publications for grey literature. This review will therefore provide evidence on this current topic, one which could have practical implications for policy-makers involved in choices which are more conducive to healthy living. ETHICS AND DISSEMINATION: No primary data will be collected since all data that will be presented in this review are based on published articles and publicly available documents, and therefore ethics committee approval is not a requirement. The findings of this review will be presented at workshops and conferences, and will be submitted for publication in a peer-reviewed journal.


Assuntos
Planejamento Ambiental , Neoplasias/epidemiologia , Parques Recreativos , Qualidade de Vida , Cidades , Humanos , Satisfação Pessoal , Projetos de Pesquisa , Comportamento de Redução do Risco , Revisões Sistemáticas como Assunto
11.
Proc Natl Acad Sci U S A ; 115(10): 2484-2489, 2018 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-29463706

RESUMO

MreB is a bacterial actin that is important for cell shape and cell wall biosynthesis in many bacterial species. MreB also plays crucial roles in Myxococcus xanthus gliding motility, but the underlying mechanism remains unknown. Here we tracked the dynamics of single MreB particles in M. xanthus using single-particle tracking photoactivated localization microscopy. We found that a subpopulation of MreB particles moves rapidly along helical trajectories, similar to the movements of the MotAB-like gliding motors. The rapid MreB motion was stalled in the mutants that carried truncated gliding motors. Remarkably, M. xanthus MreB moves one to two orders of magnitude faster than its homologs that move along with the cell wall synthesis machinery in Bacillus subtilis and Escherichia coli, and this rapid movement was not affected by the inhibitors of cell wall biosynthesis. Our results show that in M. xanthus, MreB provides a scaffold for the gliding motors while the gliding machinery drives the movement of MreB filaments, analogous to the interdependent movements of myosin motors and actin in eukaryotic cells.


Assuntos
Actinas/metabolismo , Proteínas de Bactérias/metabolismo , Movimento Celular/fisiologia , Myxococcus xanthus/metabolismo , Myxococcus xanthus/fisiologia , Actinas/química , Actinas/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas Luminescentes/química , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Microscopia de Fluorescência , Mutação , Myxococcus xanthus/química , Myxococcus xanthus/genética , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteína Vermelha Fluorescente
12.
BMC Public Health ; 17(1): 865, 2017 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-29110654

RESUMO

After publication of the article [1], it has been brought to our attention that in the original publication the third author's name was spelt incorrectly. The correct spelling is "Emmanuelle Faure". This was previously spelt as "Emmannuelle Faure". The original article has been revised to reflect this.

13.
BMC Public Health ; 17(1): 820, 2017 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-29047362

RESUMO

BACKGROUND: This paper presents the research protocol of the GoveRnance for Equity, EnviroNment and Health in the City (GREENH-City) project funded by the National Institute for Cancer (Subvention N°2017-003-INCA). In France, health inequities have tended to increase since the late 1980s. Numerous studies show the influence of social, economic, geographic and political determinants on health inequities across the life course. Exposure to environmental factors is uneven across the population and may impact on health and health inequities. In cities, green spaces contribute to creating healthy settings which may help tackle health inequities. Health in All Policies (HiAP) represents one of the key strategies for addressing social and environmental determinants of health inequities. The objective of this research is to identify the most promising interventions to operationalize the HiAP approaches at the city level to tackle health inequities through urban green spaces. It is a participatory interventional research to analyze public policy in real life setting (WHO Healthy Cities). METHOD/DESIGN: It is a mixed method systemic study with a quantitative approach for the 80 cities and a comparative qualitative multiple case-studies of 6 cities. The research combines 3 different lens: 1/a political analysis of how municipalities apply HiAP to reduce social inequities of health through green space policies and interventions 2/a geographical and topological characterization of green spaces and 3/ on-site observations of the use of green spaces by the inhabitants. RESULTS: City profiles will be identified regarding their HiAP approaches and the extent to which these cities address social inequities in health as part of their green space policy action. The analysis of the transferability of the results will inform policy recommendations in the rest of the Health City Network and widely for the French municipalities. DISCUSSION/CONCLUSION: The study will help identify factors enabling the implementation of the HiAP approach at a municipal level, promoting the development of green spaces policies in urban areas in order to tackle the social inequities in health.


Assuntos
Cidades , Planejamento Ambiental , Política de Saúde , Promoção da Saúde/métodos , França , Disparidades nos Níveis de Saúde , Humanos , Projetos de Pesquisa , Determinantes Sociais da Saúde
14.
Glob Health Promot ; 24(2): 25-34, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28535718

RESUMO

In France, there is increasing interest in health impact assessments (HIAs) and most are performed on urban projects. The field of expertise is still under development and mostly established within the public health sector. To date, in France, all HIAs conducted in urban planning are stand-alone HIAs disconnected from the required environmental impact assessment (EIA). The paper opens with an introduction of the close and complex relationship between health and urban planning, HIA and a description of key elements needed for understanding the French context. Then, the paper analyses the context and the implementation process for four HIAs in progress in order to understand the specific characteristics of urban development, identify the key stages for introducing a health perspective into urban projects, and extract avenues to be explored when adapting HIAs applied to urban planning in France. Using a qualitative multiple case study design, an analysis framework was built to compare several aspects of the four HIAs and made it possible to highlight three pathways for adapting HIA to the urban planning sector: the schedule, links between the EIA and HIA, and the complementarity of the initiatives to involve residents. Legal measures enable a point of contact that brings health institutions and cities closer together. HIA is yet another tool that public authorities now have at their fingertips to work together in strengthening democracy and in reducing social, geographical and environmental health inequalities. More research must be undertaken to develop an understanding of the practice-related context; to judge HIA's capacity to draw on existing approaches in different fields; and to explore the different avenues leading to increased health, wellbeing and equity.


Assuntos
Planejamento de Cidades , Avaliação do Impacto na Saúde/métodos , Saúde Ambiental , França , Promoção da Saúde , Humanos , Saúde Pública , Saúde da População Urbana , Reforma Urbana
15.
Hippocampus ; 26(12): 1509-1514, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27569857

RESUMO

Permanent vestibular loss has detrimental effects on the hippocampus, resulting in a disruption to spatial learning and memory, hippocampal theta rhythm and place cell field spatial coherence. Little is known about the vestibular system-related hippocampal cholinergic transmission. Since the pharmacological blockade of muscarinic acetylcholine (ACh) receptors within the hippocampus produces deficits in learning and memory, we hypothesized that ACh receptors may at least partly support the integration of vestibular input. Consequently, we examined the expression of M1 muscarinic ACh receptors in the hippocampus at 7 and 30 days following bilateral vestibular lesions (BVL) in rats using autoradiography. Animals were divided into sham (n = 12) and BVL (n = 11) groups. BVL animals received intratympanic injections of sodium arsanilate (30 mg/0.1 ml) under isoflurane anesthesia and sham animals received the same volume of saline. Analysis of the brain tissue revealed a significant reduction in the number of M1 receptors throughout the hippocampus and striatum at 30 days (P ≤ 0.0001), but not at 7 days following BVL. This suggests that the changes in learning and memory seen following vestibular damage may be in part due to the loss of M1 muscarinic receptors in the hippocampus and striatum. © 2016 Wiley Periodicals, Inc.


Assuntos
Vestibulopatia Bilateral/metabolismo , Corpo Estriado/metabolismo , Hipocampo/metabolismo , Receptor Muscarínico M1/metabolismo , Animais , Ácido Arsanílico , Autorradiografia , Vestibulopatia Bilateral/patologia , Corpo Estriado/patologia , Modelos Animais de Doenças , Progressão da Doença , Regulação para Baixo , Hipocampo/patologia , Masculino , Antagonistas Muscarínicos , Pirenzepina , Ratos Wistar , Fatores de Tempo , Trítio
16.
Epidemiol Prev ; 40(3-4): 257-64, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27436261

RESUMO

In the last decades a growing attention has been paid to the relationship between urban planning and public health. The introduction of the social model of health has stressed the importance of the determinants of health such as socioeconomic, cultural, and environmental conditions, in addition to living and working conditions. Starting from the assumption that urban planning plays a crucial role for enhancing healthy lifestyles and environments, the paper describes two different approaches to include health issues into land use plans and urban development projects. Two different evaluation tools, defined according to the Italian and French legal framework, have been compared in order to find out whether they could be considered as an innovative answer to the instance of creating a more effective cross field of work and training among urban planners and public health professionals.


Assuntos
Planejamento de Cidades/normas , Saúde Ambiental/normas , Promoção da Saúde/normas , Saúde Pública/normas , Saúde da População Urbana/normas , Cidades , França , Humanos , Itália
17.
PLoS Biol ; 11(12): e1001728, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24339744

RESUMO

Eukaryotic cells utilize an arsenal of processive transport systems to deliver macromolecules to specific subcellular sites. In prokaryotes, such transport mechanisms have only been shown to mediate gliding motility, a form of microbial surface translocation. Here, we show that the motility function of the Myxococcus xanthus Agl-Glt machinery results from the recent specialization of a versatile class of bacterial transporters. Specifically, we demonstrate that the Agl motility motor is modular and dissociates from the rest of the gliding machinery (the Glt complex) to bind the newly expressed Nfs complex, a close Glt paralogue, during sporulation. Following this association, the Agl system transports Nfs proteins directionally around the spore surface. Since the main spore coat polymer is secreted at discrete sites around the spore surface, its transport by Agl-Nfs ensures its distribution around the spore. Thus, the Agl-Glt/Nfs machineries may constitute a novel class of directional bacterial surface transporters that can be diversified to specific tasks depending on the cognate cargo and machinery-specific accessories.


Assuntos
Movimento Celular/fisiologia , Myxococcus xanthus/fisiologia , Esporos Bacterianos/fisiologia , Proteínas de Bactérias/fisiologia , Proteínas de Transporte/fisiologia , Citoesqueleto/fisiologia
18.
PLoS Genet ; 7(9): e1002268, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21931562

RESUMO

Bacteria glide across solid surfaces by mechanisms that have remained largely mysterious despite decades of research. In the deltaproteobacterium Myxococcus xanthus, this locomotion allows the formation stress-resistant fruiting bodies where sporulation takes place. However, despite the large number of genes identified as important for gliding, no specific machinery has been identified so far, hampering in-depth investigations. Based on the premise that components of the gliding machinery must have co-evolved and encode both envelope-spanning proteins and a molecular motor, we re-annotated known gliding motility genes and examined their taxonomic distribution, genomic localization, and phylogeny. We successfully delineated three functionally related genetic clusters, which we proved experimentally carry genes encoding the basal gliding machinery in M. xanthus, using genetic and localization techniques. For the first time, this study identifies structural gliding motility genes in the Myxobacteria and opens new perspectives to study the motility mechanism. Furthermore, phylogenomics provide insight into how this machinery emerged from an ancestral conserved core of genes of unknown function that evolved to gliding by the recruitment of functional modules in Myxococcales. Surprisingly, this motility machinery appears to be highly related to a sporulation system, underscoring unsuspected common mechanisms in these apparently distinct morphogenic phenomena.


Assuntos
Genes Bacterianos/fisiologia , Locomoção/genética , Modelos Biológicos , Myxococcus xanthus/genética , Myxococcus xanthus/fisiologia , Esporos Bacterianos/genética , Evolução Biológica , Filogenia , Esporos Bacterianos/metabolismo
19.
Environ Sci Technol ; 40(1): 53-60, 2006 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-16433332

RESUMO

We propose a multimedia model-based methodology to evaluate whether a chemical substance qualifies as POP-like based on overall persistence (Pov) and potential for long-range transport (LRTP). It relies upon screening chemicals against the Pov and LRTP characteristics of selected reference chemicals with well-established environmental fates. Results indicate that chemicals of high and low concern in terms of persistence and long-range transport can be consistently identified by eight contemporary multimedia models using the proposed methodology. Model results for three hypothetical chemicals illustrate that the model-based classification of chemicals according to Pov and LRTP is not always consistent with the single-media half-life approach proposed by the UNEP Stockholm Convention and thatthe models provide additional insight into the likely long-term hazards associated with chemicals in the environment. We suggest this model-based classification method be adopted as a complement to screening against defined half-life criteria at the initial stages of tiered assessments designed to identify POP-like chemicals and to prioritize further environmental fate studies for new and existing chemicals.


Assuntos
Monitoramento Ambiental/métodos , Poluentes Ambientais/análise , Substâncias Perigosas/análise , Compostos Orgânicos/análise , Movimentos do Ar , Biodegradação Ambiental , Transporte Biológico , Programas de Rastreamento , Modelos Biológicos , Medição de Risco , Fatores de Tempo , Movimentos da Água
20.
Environ Sci Technol ; 39(7): 1932-42, 2005 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-15871221

RESUMO

Overall persistence (Pov) and long-range transport potential (LRTP) of organic chemicals are environmental hazard metrics calculated with multimedia fate and transport models. Since there are several models of this type, it is important to know whether and how different model designs (model geometry, selection of compartments and processes, process descriptions) affect the results for Pov and LRTP. Using a set of 3175 hypothetical chemicals covering a broad range of partition coefficients and degradation half-lives, we systematically analyze the Pov and LRTP results obtained with nine multimedia models. We have developed several methods that make it possible to visualize the model results efficiently and to relate differences in model results to mechanistic differences between models. Rankings of the hypothetical chemicals according to Pov and LRTP are highly correlated among models and are largely determined by the chemical properties. Domains of chemical properties in which model differences lead to different results are identified, and guidance on model selection is provided for model users.


Assuntos
Monitoramento Ambiental/métodos , Poluição Ambiental/prevenção & controle , Substâncias Perigosas/análise , Modelos Químicos , Compostos Orgânicos/química , Geografia , Cinética
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