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1.
BMC Nurs ; 23(1): 160, 2024 Mar 05.
Article de Anglais | MEDLINE | ID: mdl-38443854

RÉSUMÉ

BACKGROUND: The nursing home residents' ability to carry out Activities of Daily Living (ADLs) is influenced by the physical care environment. One emerging area of interest in scientific research is the green care environment within nursing home care, where agricultural activities such as gardening and animal care are integrated alongside daily care. Previous research has neglected to explore how these environments can be employed to enhance ADL performance. This study, therefore, explores how a green care environment, specifically one with an animal shelter, can be used to support nursing home residents in their ADLs. METHODS: A focused ethnographic case study was conducted in one nursing home. Data was collected employing participatory observations, informal conversations, and semi-structured interviews, which we analyzed by employing a thematic analysis. RESULTS: Overall, 25 residents were observed for a total time of 89h, and interviews were conducted with 10 staff members. The nursing home integrates activities in the green care environment into daily care for a broad scope of residents. The analysis revealed four themes: (1) The (in)visibility of ADL, (2) Reciprocal care dynamics: Fostering ADL performance through connection and teamwork, (3) Seized and missed opportunities for meaningful integration of ADL in the physical green care environment, and Theme (4) Professional fulfillment and ADL task obligation: Views from staff and management. CONCLUSIONS: This physical green care environment carries the potential to enhance the residents' daily activities and foster better staff-resident relationships. Yet, there are varying views among staff and management regarding its integration into the residents' lives and care.

2.
Clin Oral Investig ; 26(9): 5663-5672, 2022 Sep.
Article de Anglais | MEDLINE | ID: mdl-35513582

RÉSUMÉ

OBJECTIVES: This study aims to assess whether different voxel sizes in cone-beam computed tomography (CBCT) affected surface area measurements of dehiscences and fenestrations in the mandibular anterior buccal region. MATERIALS AND METHODS: Nineteen dry human mandibles were scanned with a surface scanner (SS). Wax was attached to the mandibles as a soft tissue equivalent. Three-dimensional digital models were generated with a CBCT unit, with voxel sizes of 0.200 mm (VS200), 0.400 mm (VS400), and 0.600 mm (VS600). The buccal surface areas of the six anterior teeth were measured (in mm2) to evaluate areas of dehiscences and fenestrations. Differences between the CBCT and SS measurements were determined in a linear mixed model analysis. RESULTS: The mean surface area per tooth was 88.3 ± 24.0 mm2, with the SS, and 94.6 ± 26.5 (VS200), 95.1 ± 27.3 (VS400), and 96.0 ± 26.5 (VS600), with CBCT scans. Larger surface areas resulted in larger differences between CBCT and SS measurements (- 0.1 ß, SE = 0.02, p < 0.001). Deviations from SS measurements were larger with VS600, compared to VS200 (1.3 ß, SE = 0.05, P = 0.009). Fenestrations were undetectable with CBCT. CONCLUSIONS: CBCT imaging magnified the surface area of dehiscences in the anterior buccal region of the mandible by 7 to 9%. The larger the voxel size, the larger the deviation from SS measurements. Fenestrations were not detectable with CBCT. CLINICAL RELEVANCE: CBCT is an acceptable tool for measuring dehiscences but not fenestrations. However, CBCT overestimates the size of dehiscences, and the degree of overestimation depends on the actual dehiscence size and CBCT voxel size employed.


Sujet(s)
Processus alvéolaire , Tomodensitométrie à faisceau conique , Tomodensitométrie à faisceau conique/méthodes , Humains , Mandibule/imagerie diagnostique
3.
Ned Tijdschr Geneeskd ; 1652021 08 05.
Article de Néerlandais | MEDLINE | ID: mdl-34351719

RÉSUMÉ

Sleep disorders are prevalent and have large impact on well-being and functioning. Based on the presenting symptoms, the general practitioner can often diagnose and treat uncomplicated sleep disorders. An overview of the most common sleeping complaints, underlying diagnoses and useful treatments is given. Furthermore, we discuss a structured approach for diagnosing sleep disorders, provide criteria for referring patients with sleep disorders to sleep centers, and discuss medication both as cause as well as option for treating sleeping problems.


Sujet(s)
Médecins généralistes , Troubles de l'endormissement et du maintien du sommeil , Troubles de la veille et du sommeil , Humains , Sommeil , Troubles de la veille et du sommeil/diagnostic , Troubles de la veille et du sommeil/thérapie
4.
J Nutr Health Aging ; 24(1): 43-47, 2020.
Article de Anglais | MEDLINE | ID: mdl-31886807

RÉSUMÉ

There is a strong need in long-term care for scientific research, so older people and their families, health care professionals, policy makers, and educators can benefit from new advancements and best available evidence in every day care practice. This paper presents the model of a sustainable and successful interdisciplinary collaboration between scientists, care providers and educators in long-term care: the "Living Lab in Ageing and Long-Term Care" by Maastricht University in the Netherlands. Its mission is to contribute with scientific research to improving i) quality of life of older people and their families; ii) quality of care and iii) quality of work of those working in long-term care. Key working mechanisms are the Linking Pins and interdisciplinary partnership using a team science approach, with great scientific and societal impact. A blueprint for the model is discussed, describing its business model and challenges in getting the model operational and sustainable are discussed.


Sujet(s)
Communication interdisciplinaire , Soins de longue durée/méthodes , Qualité des soins de santé/statistiques et données numériques , Qualité de vie/psychologie , /méthodes , Sujet âgé , Sujet âgé de 80 ans ou plus , Vieillissement , Personnel de santé , Services de soins à domicile , Humains , Pays-Bas , Maisons de repos
6.
Z Gerontol Geriatr ; 51(5): 530-536, 2018 Jul.
Article de Anglais | MEDLINE | ID: mdl-28616816

RÉSUMÉ

BACKGROUND: People with dementia and their informal carers often do not receive appropriate professional support or it is not received at the right time. OBJECTIVES: Description and comparison of common pathways to formal community dementia care in eight European countries as a part of the transnational Actifcare project. MATERIALS AND METHODS: The German team was responsible for creating an individual case scenario as a starting point. The research teams in Ireland, Italy, the Netherlands, Norway, Portugal, Sweden, and the United Kingdom were then asked to describe a common pathway to formal dementia care by writing their own vignette using the provided individual case scenario. RESULTS: A transnational qualitative content analysis was used to identify the following categories as being the most important: involved professionals, dementia-specific and team-based approaches, proactive roles, and financial aspects. General practitioners (GPs) are described as being the most important profession supporting the access to formal care in all the involved countries. In some countries other professionals take over responsibility for the access procedure. Dementia-specific approaches are rarely part of standard care; team-based approaches have differing significances in each of the countries. Informal carers are mainly proactive in seeking formal care. The Nordic countries demonstrate how financial support enhances access to the professional system. CONCLUSION: Enhanced cooperation between GPs and other professions might optimize access to formal dementia care. Team-based approaches focusing on dementia care should be developed further. Informal carers should be supported and relieved in their role. Financial barriers remain which should be further investigated and reduced.


Sujet(s)
Aidants/psychologie , Démence/thérapie , Accessibilité des services de santé , Adulte , Sujet âgé , Sujet âgé de 80 ans ou plus , Europe , Femelle , Humains , Mâle , Adulte d'âge moyen , Évaluation des besoins , Qualité de vie
7.
Aging Ment Health ; 21(1): 4-17, 2017 01.
Article de Anglais | MEDLINE | ID: mdl-27869503

RÉSUMÉ

BACKGROUND: Because the pattern of illnesses changes in an aging population and many people manage to live well with chronic diseases, a group of health care professionals recently proposed reformulating the static WHO definition of health towards a dynamic one based on the ability to physically, mentally and socially adapt and self-manage. This paper is the result of a collaborative action of the INTERDEM Social Health Taskforce to operationalize this new health concept for people with dementia, more specifically the social domain, and to formulate directions for research and practice to promote social health in dementia. METHOD: Based on the expertise of the Social Health Taskforce members (N = 54) three groups were formed that worked on operationalizing the three social health dimensions described by Huber et al.: (1) capacity to fulfil potential and obligations; (2) ability to manage life with some degree of independence; (3) participation in social activities. For each dimension also influencing factors, effective interventions and knowledge gaps were inventoried. After a consensus meeting, the operationalizations of the dimensions were reviewed by the European Working Group of People with Dementia (EWGPWD). RESULTS: The social health dimensions could be well operationalized for people with dementia and are assessed as very relevant according to the Social Health Taskforce and EWGPWD. Personal (e.g. sense of coherence, competencies), disease-related (e.g. severity of cognitive impairments, comorbidity), social (support from network, stigma) and environmental factors (e.g. enabling design, accessibility) that can influence the person with dementia's social health and many interventions promoting social health were identified. CONCLUSION: A consensus-based operationalization of social health in dementia is proposed, and factors that can influence, and interventions that improve, social health in dementia identified. Recommendations are made for research and practice.


Sujet(s)
Consensus , Démence/psychologie , Soutien social , Activités de la vie quotidienne , Sujet âgé , Maladie chronique/psychologie , Maladie chronique/thérapie , Démence/thérapie , Europe , Connaissances, attitudes et pratiques en santé , Humains , Qualité de vie , Recherche sur la validité sociale/normes , Enquêtes et questionnaires
8.
BMC Geriatr ; 16(1): 169, 2016 Oct 03.
Article de Anglais | MEDLINE | ID: mdl-27716187

RÉSUMÉ

BACKGROUND: The sense of home of nursing home residents is a multifactorial phenomenon which is important for the quality of living. This purpose of this study is to investigate the factors influencing the sense of home of older adults residing in the nursing home from the perspective of residents, relatives and care professionals. METHODS: A total of 78 participants (n = 24 residents, n = 18 relatives and n = 26 care professionals) from 4 nursing homes in the Netherlands engaged in a qualitative study, in which photography was as a supportive tool for subsequent interviews and focus groups. The data were analyzed based on open ended coding, axial coding and selective coding. RESULTS: The sense of home of nursing home residents is influenced by a number of jointly identified factors, including the building and interior design; eating and drinking; autonomy and control; involvement of relatives; engagement with others and activities; quality of care are shared themes. Residents and relatives stressed the importance of having a connection with nature and the outdoors, as well as coping strategies. Relatives and care professionals emphasized the role the organization of facilitation of care played, as well as making residents feel like they still matter. CONCLUSIONS: The sense of home of nursing home residents is influenced by a multitude of factors related to the psychology of the residents, and the social and built environmental contexts. A holistic understanding of which factors influence the sense of home of residents can lead to strategies to optimize this sense of home. This study also indicated that the nursing home has a dual nature as a place of residence and a place where people are supported through numerous care strategies.


Sujet(s)
Adaptation psychologique , Vieillissement/psychologie , Maisons de retraite médicalisées , Maisons de repos , Qualité de vie/psychologie , Sujet âgé , Sujet âgé de 80 ans ou plus , Attitude du personnel soignant , Famille/psychologie , Femelle , Groupes de discussion , Personnel de santé/psychologie , Maisons de retraite médicalisées/organisation et administration , Maisons de retraite médicalisées/normes , Humains , Mâle , Pays-Bas , Maisons de repos/organisation et administration , Maisons de repos/normes , Recherche qualitative
9.
J Aging Res ; 2016: 6143645, 2016.
Article de Anglais | MEDLINE | ID: mdl-27313892

RÉSUMÉ

Purpose. To provide an overview of factors influencing the sense of home of older adults residing in the nursing home. Methods. A systematic review was conducted. Inclusion criteria were (1) original and peer-reviewed research, (2) qualitative, quantitative, or mixed methods research, (3) research about nursing home residents (or similar type of housing), and (4) research on the sense of home, meaning of home, at-homeness, or homelikeness. Results. Seventeen mainly qualitative articles were included. The sense of home of nursing home residents is influenced by 15 factors, divided into three themes: (1) psychological factors (sense of acknowledgement, preservation of one's habits and values, autonomy and control, and coping); (2) social factors (interaction and relationship with staff, residents, family and friends, and pets) and activities; and (3) the built environment (private space and (quasi-)public space, personal belongings, technology, look and feel, and the outdoors and location). Conclusions. The sense of home is influenced by numerous factors related to the psychology of the residents and the social and built environmental contexts. Further research is needed to determine if and how the identified factors are interrelated, if perspectives of various stakeholders involved differ, and how the factors can be improved in practice.

10.
Int Psychogeriatr ; 28(8): 1333-43, 2016 08.
Article de Anglais | MEDLINE | ID: mdl-27008094

RÉSUMÉ

BACKGROUND: Daily life is a dynamic and multidimensional concept, for which appropriate assessment tools are lacking. This study describes the development of the Maastricht Electronic Daily Life Observation tool (MEDLO-tool), a freely accessible, easy to use, electronic observation tool to assess relevant daily life aspects for nursing home residents with dementia. METHODS: (1) Determining relevant aspects of daily life for nursing home residents with dementia based on a literature search and expert interviews; (2) pilot testing observation procedures and operationalizations of the aspects of daily life; and (3) exploring inter-rater reliability and feasibility of the tool in a nursing home facility with 16 residents (56% female, mean age: 77). RESULTS: The following aspects of daily life are assessed with the MEDLO-tool: (1) activity (activity performed by resident, engagement in this activity, and the degree of physical effort); (2) physical environment (location of the resident and interaction with the physical environment); (3) social interaction (the level and type of social interaction, and with whom this social interaction took place); and (4) emotional well-being (mood and agitation). Each aspect of daily life is observed and scored using standardized scoring options. Agreement on the aspects is high with an average absolute agreement of 86%. Users of the MEDLO-tool indicated that it was feasible in practice and contained clear operationalization of the aspects of daily life. CONCLUSIONS: The MEDLO-tool is a promising tool to gain real time insight into the aspects of the daily lives of nursing home residents with dementia.


Sujet(s)
Activités de la vie quotidienne , Évaluation gériatrique/méthodes , Maisons de retraite médicalisées , Maisons de repos , Qualité de vie/psychologie , Sujet âgé , Sujet âgé de 80 ans ou plus , Démence/psychologie , Femelle , Humains , Relations interpersonnelles , Mâle , Reproductibilité des résultats
11.
Aging Ment Health ; 20(12): 1327-1338, 2016 12.
Article de Anglais | MEDLINE | ID: mdl-26327584

RÉSUMÉ

OBJECTIVES: To examine whether the mix of community and institutional long-term care (ILTC) for people with dementia (PwD) in Europe could be improved; assess the economic consequences of providing alternative services for particular groups of ILTC entrants and explore the transnational application of the 'Balance of Care' (BoC) approach. METHOD: A BoC study was undertaken in Estonia, Finland, France, Germany, the Netherlands, Spain, Sweden, and the UK as part of the RightTimePlaceCare project. Drawing on information about 2014 PwD on the margins of ILTC admission, this strategic planning framework identified people whose needs could be met in more than one setting, and compared the relative costs of the possible alternatives. RESULTS: The findings suggest a noteworthy minority of ILTC entrants could be more appropriately supported in the community if enhanced services were available. This would not necessarily require innovative services, but more standard care (including personal and day care), assuming quality was ensured. Potential cost savings were identified in all countries, but community care was not always cheaper than ILTC and the ability to release resources varied between nations. CONCLUSIONS: This is believed to be the first transnational application of the BoC approach, and demonstrates its potential to provide a consistent approach to planning across different health and social care systems. Better comparative information is needed on the number of ILTC entrants with dementia, unit costs and outcomes. Nevertheless, the findings offer important evidence on the appropriateness of current provision, and the opportunity to learn from different countries' experience.


Sujet(s)
Démence , Amélioration de la qualité , Allocation des ressources/normes , Sujet âgé , Services de santé communautaires/économie , Économies , Soins de jour/économie , Europe , Humains , Soins de longue durée/normes , Maisons de repos/économie , Allocation des ressources/économie
12.
BMC Geriatr ; 15: 144, 2015 Nov 02.
Article de Anglais | MEDLINE | ID: mdl-26527159

RÉSUMÉ

BACKGROUND: In nursing home care, new care environments directed towards small-scale and homelike environments are developing. The green care farm, which provides 24-h nursing home care for people with dementia, is one such new care environment. Knowledge is needed on the relation between environmental features of green care farms such as nature, domesticity and offering care in small groups and the influence on the daily lives of residents. The aim of this study is to explore (1) the daily lives of residents, (2) the quality of care and (3) the experiences of caregivers on green care farms compared with other nursing home care environments. METHODS/DESIGN: An observational longitudinal study including a baseline and a six-month follow-up measurement is carried out. Four types of nursing home care environments are included: (1) large scale nursing home ward, (2) small scale living facility on the terrain of a larger nursing home (3) stand-alone small scale living facility and (4) green care farm. Quality of care is examined through structure, process and outcome indicators. The primary outcome measure is the daily life of residents, assessed by ecological momentary assessments. Aspects of daily life include (1) activity (activity performed by the resident, the engagement in this activity and the degree of physical effort); (2) physical environment (the location of the resident and the interaction with the physical environment); (3) social environment (the level and type of social interaction, and with whom this social interaction took place) and (4) psychological well-being (mood and agitation). In addition, social engagement, quality of life, behavioral symptoms and agitation are evaluated through questionnaires. Furthermore, demographics, cognitive impairment, functional dependence and the severity of dementia are assessed. Semi-structured interviews are performed with caregivers regarding their experiences with the different nursing home care environments. DISCUSSION: This is the first study investigating green care farms providing 24-h nursing home care for people with dementia. The study provides valuable insight into the daily lives of residents, the quality of care, and the experiences of caregivers at green care farms in comparison with other nursing home care environments including small-scale care environments and large scale nursing home wards.


Sujet(s)
Agriculture , Symptômes comportementaux/prévention et contrôle , Aidants/psychologie , Démence , Maisons de retraite médicalisées/organisation et administration , Maisons de repos/organisation et administration , Qualité de vie/psychologie , Sujet âgé , Démence/psychologie , Démence/thérapie , Femelle , Environnement d'établissement de santé/méthodes , Humains , Relations interpersonnelles , Études longitudinales , Mâle , Pays-Bas , Environnement social , Enquêtes et questionnaires
13.
Tijdschr Gerontol Geriatr ; 44(6): 261-71, 2013 Dec.
Article de Néerlandais | MEDLINE | ID: mdl-24203378

RÉSUMÉ

Institutional dementia care is increasingly directed towards small-scale and homelike care environments, in The Netherlands as well as abroad. In these facilities, a small number of residents, usually six to eight, live together, and normal daily household activities and social participation are emphasized. In a quasi-experimental study, we studied the effects of small-scale, homelike care environments on residents (n = 259), family caregivers (n = 206) and nursing staff (n = 305). We compared two types of institutional nursing care during a 1 year period (baseline assessment and follow-up measurements at 6 and 12 months): (28) small-scale, homelike care environments and (21) psychogeriatric wards in traditional nursing homes. A matching procedure was applied to increase comparability of residents at baseline regarding functional status and cognition. This study was unable to demonstrate convincing overall effects of small-scale, homelike care facilities. On our primary outcome measures, such as quality of life and behaviour of residents and job satisfaction and motivation of nursing staff, no differences were found with traditional nursing homes. We conclude that small-scale, homelike care environments are not necessarily a better care environment than regular nursing homes and other types of living arrangements should be considered carefully. This provides opportunities for residents and their family caregivers to make a choice which care facility suits their wishes and beliefs best.


Sujet(s)
Aidants/psychologie , Démence/soins infirmiers , Personnel infirmier/psychologie , Évaluation des résultats et des processus en soins de santé , Environnement social , Sujet âgé , Sujet âgé de 80 ans ou plus , Démence/psychologie , Femelle , Études de suivi , Foyers collectifs/normes , Maisons de retraite médicalisées/normes , Humains , Relations interpersonnelles , Soins de longue durée/psychologie , Soins de longue durée/normes , Mâle , Pays-Bas , Maisons de repos/normes , Satisfaction des patients , Qualité de vie
15.
Neurogenetics ; 6(4): 195-9, 2005 Dec.
Article de Anglais | MEDLINE | ID: mdl-16170568

RÉSUMÉ

Lysosomal free sialic acid storage diseases are recessively inherited allelic neurodegenerative disorders that include Salla disease (SD) and infantile sialic acid storage disease (ISSD) caused by mutations in the SLC17A5 gene encoding for a lysosomal membrane protein, sialin, transporting sialic acid from lysosomes. The classical form of SD, enriched in the Finnish population, is related to the p.R39C designed Salla(FIN) founder mutation. A more severe phenotype is due both to compound heterozygosity for the p.R39C mutation and to different mutations. The p.R39C has not been reported in ISSD. We identified the first case of SD caused by the homozygosity for p.K136E (c.406A>G) mutation, showing a severe clinical picture, as demonstrated by the early age at onset, the degree of motor retardation, the occurrence of peripheral nerve involvement, as well as cerebral hypomyelination. Recently, in vitro functional studies have shown that the p.K136E mutant produces a mislocalization and a reduced activity of the intracellular sialin. We discuss the in vivo phenotypic consequence of the p.K136E in relation to the results obtained by the in vitro functional characterization of the p.K136E mutant. The severity of the clinical picture, in comparison with the classical SD, may be explained by the fact that the p.K136E mutation mislocalizes the protein to a greater degree than p.R39C. On the other hand, the presence of a residual transport activity may account for the absence of hepatosplenomegaly, dysostosis multiplex, and early lethality typical of ISSD and related to the abolished transport activity found in this latter form.


Sujet(s)
Homozygote , Mutation , Transporteurs d'anions organiques/génétique , Maladie de surcharge en acide sialique/génétique , Symporteurs/génétique , Encéphale/anatomopathologie , Enfant d'âge préscolaire , Génotype , Humains , Italie , Lysosomes/métabolisme , Imagerie par résonance magnétique , Mâle , Acide N-acétyl-neuraminique/métabolisme , Phénotype
16.
FEMS Microbiol Lett ; 78(1): 85-8, 1992 Nov 15.
Article de Anglais | MEDLINE | ID: mdl-1468620

RÉSUMÉ

The FIS protein (factor for inversion stimulation) is known to activate the transcription of rRNA and tRNA operons in Escherichia coli. In this report the growth behaviour of a fis bacterium was studied under steady-state conditions and in competition experiments with a wild-type bacterium in a chemostat. The growth rate of the fis bacterium was reduced as compared to that of an isogenic wild-type and this reduction increased linearly with increasing growth rate. A similar result was obtained in competition experiments in a chemostat, with the selection factor increasing linearly with the growth rate.


Sujet(s)
Protéines de transport/génétique , Protéines Escherichia coli , Escherichia coli/croissance et développement , Régulation de l'expression des gènes bactériens , Escherichia coli/génétique , Facteur de stimulation d'inversion , Facteurs d'intégration de l'hôte , Opéron
17.
Nucleic Acids Res ; 20(15): 4077-81, 1992 Aug 11.
Article de Anglais | MEDLINE | ID: mdl-1380692

RÉSUMÉ

Transcription of the thrU(tufB) operon is trans-activated by the protein FIS which binds to the promoter upstream activator sequence (UAS). Deletions of parts of the UAS and insertions show that optimal trans-activation requires occupation by FIS of the two FIS-binding regions on the UAS and specific helical positioning of these regions. On the basis of these and other data, a model for the mechanism of thrU(tufB) trans-activation by FIS is proposed. This model implies that the mechanisms underlying stimulation by FIS of two totally different processes: inversion of viral DNA segments and transcription of stable RNA operons, are essentially the same.


Sujet(s)
Protéines de transport/génétique , Protéines Escherichia coli , Escherichia coli/génétique , Facteur Tu d'élongation de la chaîne peptidique/génétique , ARN de transfert/génétique , Activation de la transcription/génétique , Protéines bactériennes/génétique , Séquence nucléotidique , Sites de fixation/génétique , Analyse de mutations d'ADN , Protéines de liaison à l'ADN/génétique , Facteur de stimulation d'inversion , Facteurs d'intégration de l'hôte , Données de séquences moléculaires , Conformation d'acide nucléique , Opéron/génétique , ARN bactérien/génétique , Recombinaison génétique/génétique , Séquences d'acides nucléiques régulatrices/génétique
18.
J Bacteriol ; 174(3): 921-9, 1992 Feb.
Article de Anglais | MEDLINE | ID: mdl-1732224

RÉSUMÉ

In Escherichia coli transcription of the tRNA operon thrU (tufB) and the rRNA operon rrnB is trans-activated by the protein FIS. This protein, which stimulates the inversion of various viral DNA segments, binds specifically to a cis-acting sequence (designated UAS) upstream of the promoter of thrU (tufB) and the P1 promoter of the rrnB operon. There are indications that this type of regulation is representative for the regulation of more stable RNA operons. In the present investigation we have studied UAS-dependent transcription activation of the thrU (tufB) operon in the presence and absence of FIS during a normal bacterial growth cycle and after a nutritional shift-up. In early log phase the expression of the operon rises steeply in wild-type cells, whereafter it declines. Concomitantly, a peak of the cellular FIS concentration is observed. Cells in the stationary phase are depleted of FIS. The rather abrupt increase of transcription activation depends on the nutritional quality of the medium. It is not seen in minimal medium. After a shift from minimal to rich medium, a peak of transcription activation and of FIS concentration is measured. This peak gets higher as the medium gets more strongly enriched. We conclude that a correlation between changes of the UAS-dependent activation of the thrU (tufB) operon and changes of the cellular FIS concentration under a variety of experimental conditions exists. This correlation strongly suggests that the production of FIS responds to environmental signals, thereby trans-activating the operon. Cells unable to produce FIS (fis cells) also show an increase of operon transcription in the early log phase and after a nutritional shift-up, albeit less pronounced than that wild-type cells. Presumably it is controlled by the ribosome feedback regulatory system. cis activation of the operon by the upstream activator sequence is apparent in the absence of FIS. This activation is constant throughout the entire growth cycle and is independent of nutritional factors. The well-known growth rate-dependent control, displayed by exponentially growing cells studied under various nutritional conditions, is governed by two regulatory mechanisms: repression, presumably by ribosome feedback inhibition, and stimulation by trans activation. FIS allows very fast bacterial growth.


Sujet(s)
Protéines de transport/physiologie , Division cellulaire/physiologie , Protéines Escherichia coli , Escherichia coli/physiologie , ARN de transfert de la thréonine/métabolisme , Activation de la transcription/physiologie , Protéines de transport/analyse , Division cellulaire/génétique , Facteur de stimulation d'inversion , Régulation de l'expression des gènes bactériens , Facteurs d'intégration de l'hôte , Opéron/génétique , Transduction du signal/physiologie , Transcription génétique/effets des médicaments et des substances chimiques , Transcription génétique/physiologie
19.
Biochimie ; 73(6): 713-8, 1991 Jun.
Article de Anglais | MEDLINE | ID: mdl-1764517

RÉSUMÉ

The upstream activator sequence (UAS) of the thrU(tufB) operon, which is the target of the trans-activating protein FIS, has a bent structure. Here we show that the center of bending lies around position -95, between the two FIS-binding regions. Studies with fis+ and fis- cells show that FIS-induced bending of the UAS plays a major role in the trans-activation of the thrU(tufB) operon. This has been concluded from the finding that insertions of small DNA segments, comprising less than one or two complete helix turns, in the junction of the UAS and the RNA polymerase-binding site reduce transcription significantly. Partial restoration of transcriptional activity occurs when one or more full helix turns are inserted. These data are in line with but do not prove that a direct interaction between FIS and RNA polymerase is involved in trans-activation. A role of bending per se resulting from FIS/DNA interaction cannot be excluded.


Sujet(s)
Protéines de transport/métabolisme , Protéines Escherichia coli , Escherichia coli/génétique , Séquences d'acides nucléiques régulatrices/génétique , Transcription génétique/génétique , Séquence nucléotidique , Sites de fixation , Cartographie chromosomique , Protéines de liaison à l'ADN/métabolisme , Facteur de stimulation d'inversion , Galactokinase/métabolisme , Régulation de l'expression des gènes bactériens/génétique , Facteurs d'intégration de l'hôte , Données de séquences moléculaires , Mutagenèse par insertion , Conformation d'acide nucléique , Activation de la transcription
20.
Biochim Biophys Acta ; 1050(1-3): 302-6, 1990 Aug 27.
Article de Anglais | MEDLINE | ID: mdl-2207159

RÉSUMÉ

FIS, the Escherichia coli protein that stimulates the inversion of various DNA segments by binding to a recombinational enhancer, trans-activates a number of stable RNA operons and binds to the upstream activator sequence (UAS) of these operons (Nilsson et al. (1990) EMBO J. 9, 727). In a search for potential FIS-binding sites we have compared UASs of other stable RNA operons with a consensus FIS-binding sequence, compiled by comparing recombinational enhancers. Such sites can thus be recognized upstream of all rRNA and 13 tRNA operons. Matching with the consensus sequence varied, suggesting that the affinity of FIS for the sites differed. Accordingly, FIS binding to an upstream sequence of the metY(nusA) operon was found to be weaker than that to the UAS of the thrU(tufB) operon. No FIS binding sites were found upstream three tRNA operons.


Sujet(s)
Protéines de transport/métabolisme , Protéines Escherichia coli , Escherichia coli/génétique , Opéron , ARN ribosomique/génétique , ARN de transfert/génétique , Anticodon/génétique , Séquence nucléotidique , Sites de fixation , Protéines de liaison à l'ADN/métabolisme , Escherichia coli/métabolisme , Facteur de stimulation d'inversion , Facteurs d'intégration de l'hôte , Données de séquences moléculaires
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