Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 235
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Nature ; 560(7716): E1, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29875404

RESUMO

In this Brief Communications Arising Reply, the affiliation for author P. H. Templer was incorrectly listed as 'Department of Ecology & Evolutionary Biology, University of California Irvine, Irvine, California 92697, USA' instead of 'Department of Biology, Boston University, Boston, Massachusetts 02215, USA'. This has been corrected online.

2.
Nature ; 540(7631): 104-108, 2016 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-27905442

RESUMO

The majority of the Earth's terrestrial carbon is stored in the soil. If anthropogenic warming stimulates the loss of this carbon to the atmosphere, it could drive further planetary warming. Despite evidence that warming enhances carbon fluxes to and from the soil, the net global balance between these responses remains uncertain. Here we present a comprehensive analysis of warming-induced changes in soil carbon stocks by assembling data from 49 field experiments located across North America, Europe and Asia. We find that the effects of warming are contingent on the size of the initial soil carbon stock, with considerable losses occurring in high-latitude areas. By extrapolating this empirical relationship to the global scale, we provide estimates of soil carbon sensitivity to warming that may help to constrain Earth system model projections. Our empirical relationship suggests that global soil carbon stocks in the upper soil horizons will fall by 30 ± 30 petagrams of carbon to 203 ± 161 petagrams of carbon under one degree of warming, depending on the rate at which the effects of warming are realized. Under the conservative assumption that the response of soil carbon to warming occurs within a year, a business-as-usual climate scenario would drive the loss of 55 ± 50 petagrams of carbon from the upper soil horizons by 2050. This value is around 12-17 per cent of the expected anthropogenic emissions over this period. Despite the considerable uncertainty in our estimates, the direction of the global soil carbon response is consistent across all scenarios. This provides strong empirical support for the idea that rising temperatures will stimulate the net loss of soil carbon to the atmosphere, driving a positive land carbon-climate feedback that could accelerate climate change.


Assuntos
Atmosfera/química , Ciclo do Carbono , Carbono/análise , Geografia , Aquecimento Global , Solo/química , Bases de Dados Factuais , Ecossistema , Retroalimentação , Modelos Estatísticos , Reprodutibilidade dos Testes , Temperatura
3.
Neuropathol Appl Neurobiol ; 46(3): 240-254, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31216593

RESUMO

AIMS: In the search for blood-based biomarkers of neurodegenerative diseases, we characterized the concentration of total prion protein (t-PrP) in the plasma of neurodegenerative dementias. We aimed to assess its accuracy in this differential diagnostic context. METHODS: Plasma t-PrP was measured in 520 individuals including healthy controls (HC) and patients diagnosed with neurological disease control (ND), Alzheimer's disease (AD), sporadic Creutzfeldt-Jakob disease (sCJD), frontotemporal dementia (FTD), Lewy body dementia (LBD) and vascular dementia (VaD). Additionally, t-PrP was quantified in genetic prion diseases and iatrogenic CJD. The accuracy of t-PrP discriminating the diagnostic groups was evaluated and correlated with demographic, genetic and clinical data in prion diseases. Markers of blood-brain barrier impairment were investigated in sCJD brains. RESULTS: Compared to HC and ND, elevated plasma t-PrP concentrations were detected in sCJD, followed by FTD, AD, VaD and LBD. In sCJD, t-PrP was associated neither with age nor sex, but with codon 129 PRNP genotype. Plasma t-PrP concentrations correlated with cerebrospinal fluid (CSF) markers of neuro-axonal damage, but not with CSF t-PrP. In genetic prion diseases, plasma t-PrP was elevated in all type of mutations investigated. In sCJD brain tissue, extravasation of immunoglobulin G and the presence of swollen astrocytic end-feet around the vessels suggested leakage of blood-brain barrier as a potential source of increased plasma t-PrP. CONCLUSIONS: Plasma t-PrP is elevated in prion diseases regardless of aetiology. This pilot study opens the possibility to consider plasma t-PrP as a promising blood-based biomarker in the diagnostic of prion disease.


Assuntos
Biomarcadores/sangue , Demência/diagnóstico , Doenças Neurodegenerativas/diagnóstico , Doenças Priônicas/diagnóstico , Proteínas Priônicas/sangue , Adulto , Idoso , Demência/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doenças Neurodegenerativas/sangue , Doenças Priônicas/sangue
4.
Unfallchirurg ; 123(11): 904-908, 2020 Nov.
Artigo em Alemão | MEDLINE | ID: mdl-32930829

RESUMO

Various diseases or groups of diseases can trigger bone marrow edema (BME). The task of the appraiser is to work out the role of a diagnosed BME in the context of the causality based on liability; however, the inconsistent ICD 10 coding of the BME complex also poses a problem, especially for medically untrained insurance clerks. The coding of the BME as a fracture provided by the coding guidelines poses a problem when assessing reserves for damage settlement. Based on the etiology of BME an algorithm is presented that should make it easier for the expert as well as for the insurance clerk in the case of liability and also for the private accident insurance to classify the diagnosis of BME in the case.


Assuntos
Doenças da Medula Óssea , Medula Óssea , Fraturas Ósseas , Medula Óssea/patologia , Doenças da Medula Óssea/diagnóstico , Edema , Humanos , Seguro Saúde , Imageamento por Ressonância Magnética
6.
ScientificWorldJournal ; 2019: 5416806, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30956624

RESUMO

PURPOSE: Most studies about retinal detachment cover a limited follow-up period. The purpose of this research is to assess the long-term results after pars plana vitrectomy (PPV) and scleral buckle (SB) surgery in patients with rhegmatogenous retinal detachment (RRD). METHODS: 155 patients with RRD are treated either with SB or PPV with a mean follow-up of more than 5 years. Retrospective analysis of patient data with RRD was performed between January 2006 and June 2008 at a tertiary eye clinic. RESULTS: Overall primary success rate was 85.2% (PPV: 84.6%, SB: 89.5%; p=0.57). 90.5% of redetachments appeared within the first 124 days. No significant different success rate was found for vitrectomy with and without additional encircling band (p=0.09). No advantage of a supplemental encircling band in cases of preoperative inferior breaks was seen (p=0.81). Patients of SB group were treated more frequently in follow-up time because of epiretinal membrane (ERM) (SB: 15.5% versus PPV: 7.3%). No patient of the PPV group without intraoperative use of endolaser cerclage (14.7%) had any peeling surgery postoperatively. CONCLUSION: Redetachment rates of both methods are comparable in a clinical setting where PPV is considered a suitable method for pseudophakic patients and in complex cases and SB was performed in younger phakic patients with clearly identified retinal tears. PPV seems to show a more heterogenous pattern of complications. No advantage of a supplemental encircling band could be found in these case series of patients with primary RRD. No relevant long-term risk of redetachment was seen after SB.


Assuntos
Complicações Pós-Operatórias/epidemiologia , Descolamento Retiniano/cirurgia , Recurvamento da Esclera/efeitos adversos , Vitrectomia/efeitos adversos , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Período Pós-Operatório , Recidiva , Estudos Retrospectivos , Resultado do Tratamento
7.
BJOG ; 124(12): 1891-1898, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28029217

RESUMO

OBJECTIVE: Gestational diabetes mellitus (GDM) potentially harms the child before birth. We previously found GDM to be associated with developmental changes in the central nervous system. We now hypothesise that GDM may also impact on the fetal autonomic nervous system under metabolic stress like an oral glucose tolerance test (OGTT). DESIGN: We measured heart rate variability (HRV) of mothers and fetuses during a three-point OGTT using fetal magnetocardiography (fMCG). SETTING: Measurements were performed in the fMEG Centre in Tübingen. POPULATION: After exclusion of 23 participants, 13 pregnant women with GDM and 36 pregnant women with normal glucose tolerance were examined. METHODS: All women underwent the same examination setting with OGTT during which fMCG was recorded three times. MAIN OUTCOME MEASURE(S): Parameters of heart rate variability were measured. RESULTS: Compared with mothers with normal glucose regulation, mothers with GDM showed increased heart rate but no significant differences of maternal HRV. In contrast, HRV in fetuses of mothers with GDM differed from those in the metabolically healthy group regarding standard deviation normal to normal beat (SDNN) (P = 0.012), low-frequency band (P = 0.008) and high-frequency band (P = 0.031). These HRV parameters exhibit a decrease only in GDM fetuses during the second hour of the OGTT. CONCLUSIONS: These results show an altered response of the fetal autonomic nervous system to metabolic stress in GDM-complicated pregnancies. Hence, disturbances in maternal glucose metabolism might not only impact on the central nervous system of the fetus but may also affect the fetal autonomic nervous system. TWEETABLE ABSTRACT: Metabolic stress reveals a different response of fetal autonomic nervous system in GDM-complicated pregnancies.


Assuntos
Diabetes Gestacional/fisiopatologia , Glucose/farmacologia , Frequência Cardíaca Fetal/efeitos dos fármacos , Magnetocardiografia/métodos , Diagnóstico Pré-Natal/métodos , Adulto , Sistema Nervoso Autônomo/efeitos dos fármacos , Diabetes Gestacional/diagnóstico , Feminino , Glucose/administração & dosagem , Teste de Tolerância a Glucose , Humanos , Gravidez , Adulto Jovem
8.
BJOG ; 122(9): 1184-90, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25846345

RESUMO

OBJECTIVE: Fetal magnetoencephalography records fetal brain activity non-invasively. Delayed brain responses were reported for fetuses weighing below the tenth percentile. To investigate whether this delay indicates delayed brain maturation resulting from placental insufficiency, this study distinguished two groups of fetuses below the tenth percentile: growth-restricted fetuses with abnormal umbilical artery Doppler velocity (IUGR) and constitutionally small-for-gestational-age fetuses with normal umbilical artery Doppler findings (SGA) were compared with fetuses of adequate weight for gestational age (AGA), matched for age and behavioural state. DESIGN: A case-control study of matched pairs. SETTING: Fetal magnetoencephalography-Center at the University Hospital of Tuebingen. POPULATION: Fourteen IUGR fetuses and 23 SGA fetuses were matched for gestational age and fetal behavioural state with 37 healthy, normal-sized fetuses. METHODS: A 156-channel fetal magentoencephalography system was used to record fetal brain activity. Light flashes as visual stimulation were applied to the fetus. The Student's t-test for paired groups was performed. MAIN OUTCOME MEASURE: Latency of fetal visual evoked magnetic responses (VER). RESULTS: The IUGR fetuses showed delayed VERs compared with controls (IUGR, 233.1 ms; controls, 184.6 ms; P = 0.032). SGA fetuses had similar evoked response latencies compared with controls (SGA, 216.1 ms; controls, 219.9 ms; P = 0.828). Behavioural states were similarly distributed. CONCLUSION: Visual evoked responses are delayed in IUGR fetuses, but not in SGA. Fetal behavioural state as an influencing factor of brain response latency was accounted for in the comparison. This reinforces that delayed brain maturation is the result of placental insufficiency.


Assuntos
Encéfalo/fisiopatologia , Retardo do Crescimento Fetal/fisiopatologia , Feto/irrigação sanguínea , Recém-Nascido Pequeno para a Idade Gestacional , Magnetoencefalografia , Insuficiência Placentária/fisiopatologia , Índice de Apgar , Velocidade do Fluxo Sanguíneo , Encéfalo/embriologia , Estudos de Casos e Controles , Feminino , Desenvolvimento Fetal , Retardo do Crescimento Fetal/diagnóstico por imagem , Alemanha , Humanos , Recém-Nascido , Masculino , Análise por Pareamento , Gravidez , Ultrassonografia Doppler , Artérias Umbilicais/diagnóstico por imagem
9.
Foot Ankle Surg ; 21(3): 211-3, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26235863

RESUMO

A 62-year-old female patient presented with a symptomatic metal allergy six weeks after first metatarsophalangeal total joint replacement using ROTOGLIDE implant. Preoperatively, there was no history of hypersensitivity. The symptomatic dermatitis was evaluated using dermal patch testing. The implant had to be removed. The possible agents for the allergic reaction are discussed.


Assuntos
Artroplastia de Substituição , Hallux Rigidus/cirurgia , Hipersensibilidade/etiologia , Prótese Articular/efeitos adversos , Metais/efeitos adversos , Articulação Metatarsofalângica/cirurgia , Articulação do Dedo do Pé/cirurgia , Feminino , Hallux Rigidus/fisiopatologia , Humanos , Pessoa de Meia-Idade , Amplitude de Movimento Articular
10.
Lupus ; 23(9): 919-25, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24639473

RESUMO

OBJECTIVE: The objective of this report is to detect cardiac time intervals (CTIs) in fetuses exposed to SSA/Ro-SSB/La antibodies in relation to gestational age (GA) and fetal weight and compared them with a control cohort. METHODS: Fetal magnetocardiography (fMCG) recordings were conducted on a biomagnetic device dedicated to obstetrical measurement starting in the second trimester. Fetal cardiac time intervals of 87 healthy fetuses of normal gestation (control group) were compared to 11 fetuses exposed to maternal SSA/Ro-SSB/La antibodies (study group). RESULTS: fCTIs were analyzed starting at 17 weeks of GA. Atrial and ventricular depolarization times increased with GA in both groups. PQ segments were significantly longer in the study group (50.8 ms vs. 60.2 ms; p < 0.001) independent of GA or fetal weight. PQ segment prolongation was more obvious in the study group prior to 30 weeks of GA. CONCLUSION: PQ segment prolongation can be interpreted as early AV-node involvement caused by maternal SSA/Ro-SSB/La antibodies. The age dependency of the PQ segment should be taken into account in further studies.


Assuntos
Bloqueio Atrioventricular/diagnóstico , Bloqueio Atrioventricular/imunologia , Cardiotocografia , Magnetocardiografia , Diagnóstico Pré-Natal , Feminino , Humanos , Gravidez , Estudos Prospectivos , Fatores de Risco , Fatores de Tempo
11.
Ecology ; 93(8): 1816-29, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22928411

RESUMO

Effects of anthropogenic nitrogen (N) deposition and the ability of terrestrial ecosystems to store carbon (C) depend in part on the amount of N retained in the system and its partitioning among plant and soil pools. We conducted a meta-analysis of studies at 48 sites across four continents that used enriched 15N isotope tracers in order to synthesize information about total ecosystem N retention (i.e., total ecosystem 15N recovery in plant and soil pools) across natural systems and N partitioning among ecosystem pools. The greatest recoveries of ecosystem 15N tracer occurred in shrublands (mean, 89.5%) and wetlands (84.8%) followed by forests (74.9%) and grasslands (51.8%). In the short term (< 1 week after 15N tracer application), total ecosystem 15N recovery was negatively correlated with fine-root and soil 15N natural abundance, and organic soil C and N concentration but was positively correlated with mean annual temperature and mineral soil C:N. In the longer term (3-18 months after 15N tracer application), total ecosystem 15N retention was negatively correlated with foliar natural-abundance 15N but was positively correlated with mineral soil C and N concentration and C:N, showing that plant and soil natural-abundance 15N and soil C:N are good indicators of total ecosystem N retention. Foliar N concentration was not significantly related to ecosystem 15N tracer recovery, suggesting that plant N status is not a good predictor of total ecosystem N retention. Because the largest ecosystem sinks for 15N tracer were below ground in forests, shrublands, and grasslands, we conclude that growth enhancement and potential for increased C storage in aboveground biomass from atmospheric N deposition is likely to be modest in these ecosystems. Total ecosystem 15N recovery decreased with N fertilization, with an apparent threshold fertilization rate of 46 kg N x ha(-1) x yr(-1) above which most ecosystems showed net losses of applied 15N tracer in response to N fertilizer addition.


Assuntos
Ecossistema , Ciclo do Nitrogênio , Nitrogênio/química , Altitude , Amônia/química , Vazamento de Resíduos Químicos , Nitratos/química , Isótopos de Nitrogênio , Chuva , Temperatura
12.
Int J Androl ; 35(3): 273-82, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22404257

RESUMO

Contemporary American and European girls experience breast development at earlier ages compared with 15-20 years ago. Alterations in BMI alone cannot account for these changes. Several currently used pesticides possess endocrine disrupting properties and may interfere with reproductive development, but human data are sparse. We examined girls whose mothers worked in greenhouses in the first trimester of pregnancy to assess the long-term effects of prenatal pesticide exposure on puberty. Mothers were prenatally categorized as exposed or unexposed to pesticides. We studied the offspring of these greenhouse workers, and evaluated the anthropometry, pubertal staging in the girls, and blood samples were drawn at 3 months of age (n = 90) and again once at school age (6-11 years, n = 83). No clinical and biochemical differences were found between the exposed and unexposed girls at 3 months of age. Mean onset of B2+ was 8.9 years (95% CI: 8.2; 9.7) in prenatally exposed girls, compared with 10.4 years (9.2; 17.6) in the unexposed (p = 0.05), and 10.0 (9.7-10.3) years in a Danish reference population (p = 0.001). Exposed girls had higher serum androstenedione levels (geometric means: 0.58 vs. 0.79 nmol/L, p = 0.046) and lower Anti-Müllerian Hormone (AMH) compared with the unexposed (geometric means: 16.4 vs. 21.3 pmol/L, p > 0.05) and the reference group (20.2 pmol/L, p = 0.012). Levels of testosterone, estradiol, prolactin, FSH, LH, SHBG, DHEAS, DHT, Inhibin A and Inhibin B did not differ between the groups. In conclusion, our findings suggest that prenatal exposure to currently approved pesticides may cause earlier breast development in girls. This association appeared not to be because of changes in gonadotropins, but rather to higher androgen levels, which indirectly may increase oestrogens through aromatization. In addition, lower serum AMH levels indicated a reduced pool of antral ovarian follicles. The long-term consequences of our findings with regard to establishment of future reproductive function still remain unknown.


Assuntos
Mama/crescimento & desenvolvimento , Praguicidas/efeitos adversos , Efeitos Tardios da Exposição Pré-Natal , Agricultura , Androstenodiona/sangue , Mama/efeitos dos fármacos , Criança , Feminino , Humanos , Lactente , Gravidez , Medição de Risco
13.
Unfallchirurg ; 115(3): 267-72, 2012 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-21748339

RESUMO

Exposed bradytrophic tissue in regions with high mechanical loading is an indication for defect coverage with (myo-, adipo-) fasciocutaneous flaps. In this case, distally based sural flaps were used for bilateral coverage of defects in weight-bearing areas of feet after fourth-degree frostbite. Residual defects can be covered with a split skin mesh graft. The definitive prosthetic supply of the foot assumes a stabilized plantar soft tissue situation. Among its advantages in comparison to free microvascular flaps, the locally based fasciocutaneous flap can be harvested with less donor site morbidity after elevation and does not require secondary debulking. It has been shown that the reduced stability at the border zone between flap and mesh graft has an adverse effect.


Assuntos
Traumatismos do Pé/cirurgia , Congelamento das Extremidades/cirurgia , Calcanhar/lesões , Calcanhar/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Retalhos Cirúrgicos , Resultado do Tratamento
14.
Comput Methods Biomech Biomed Engin ; 25(16): 1835-1851, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35435781

RESUMO

Bone remodelling is a complex biomechanical process, which has been studied widely based on the restrictions of local continuum theory. To provide a nonlocal bone remodelling framework, we propose, for the first time, a peridynamic formulation on the macroscale. We illustrate our implementation with a common benchmark test as well as two load cases of the proximal femur. On the one hand, results of our peridynamic model with diminishing nonlocality measure converge to the results of a local finite element model. On the other hand, increasing the neighbourhood size shows to what extent the additional degree of freedom, the nonlocality, can influence the density evolution.


Assuntos
Remodelação Óssea , Modelos Biológicos , Fêmur , Análise de Elementos Finitos , Densidade Óssea
15.
Genes Immun ; 12(2): 90-9, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21270828

RESUMO

Complement factor H (CFH) is a regulator of the alternative complement activation pathway. Mutations in the CFH gene are associated with atypical hemolytic uremic syndrome, membranoproliferative glomerulonephritis type II and C3 glomerulonephritis. Here, we report a 6-month-old CFH-deficient child presenting with endocapillary glomerulonephritis rather than membranoproliferative glomerulonephritis (MPGN) or C3 glomerulonephritis. Sequence analyses showed homozygosity for a novel CFH missense mutation (Pro139Ser) associated with severely decreased CFH plasma concentration (<6%) but normal mRNA splicing and expression. The father was heterozygous carrier of the mutation, but the mother was a non-carrier. Thus, a large deletion in the maternal CFH locus or uniparental isodisomy was suspected. Polymorphic markers across chromosome 1 showed homozygosity for the paternal allele in all markers and a lack of the maternal allele in six informative markers. This combined with a comparative genomic hybridization assay demonstrated paternal isodisomy. Uniparental isodisomy increases the risk of homozygous variations in other genes on the affected chromosome. Therefore, we analyzed other susceptibility genes on chromosome 1 and found no sequence variation in membrane cofactor protein, but homozygosity for the common deletion of CFH-related proteins 1 and 3, which may contribute to the early onset of disease.


Assuntos
Fator H do Complemento/deficiência , Fator H do Complemento/genética , Glomerulonefrite/genética , Glomerulonefrite/imunologia , Dissomia Uniparental/genética , Alelos , Proteínas Sanguíneas/genética , Cromossomos Humanos Par 1/genética , Proteínas Inativadoras do Complemento C3b/genética , Via Alternativa do Complemento/genética , Via Alternativa do Complemento/imunologia , Feminino , Regulação da Expressão Gênica , Variação Genética , Glomerulonefrite/patologia , Heterozigoto , Homozigoto , Humanos , Lactente , Proteína Cofatora de Membrana/genética , Proteína Cofatora de Membrana/imunologia , Mutação de Sentido Incorreto , RNA Mensageiro/genética , Análise de Sequência de DNA
16.
J Appl Microbiol ; 108(4): 1167-74, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19735319

RESUMO

AIM: To determine the microbial composition of biofilms in domestic toilets by molecular means. METHODS AND RESULTS: Genomic DNA was extracted from six biofilm samples originating from households around Düsseldorf, Germany. While no archaeal 16S rRNA or fungal ITS genes were detected by PCR, fingerprinting of bacterial 16S rRNA genes revealed a diverse community in all samples. These communities also differed considerably between the six biofilms. Using the Ribosomal Database Project (RDP) classifier tool, 275 cloned 16S rRNA gene sequences were assigned to 11 bacterial phyla and 104 bacterial genera. Only 15 genera (representing 121 sequences affiliated with Acidobacteria, Actinobacteria, Bacteroidetes, Planctomycetes and Proteobacteria) occurred in at least half of the samples or contributed at least 10% of the sequences in a single biofilm. These sequences were defined as 'typical' for toilet biofilms, and they were examined in more detail. On a 97% sequence similarity level, these sequences represented 56 species. Twelve of these were closely related to well-described bacterial species, and only two of them were categorized as belonging to risk group 2. No 16S rRNA genes of typical faecal bacteria were detected in any sample. Virtually all 'typical' clones were found to be closely related to bacteria or to sequences obtained from environmental sources, implicating that the flushing water is the main source of recruitment. CONCLUSION: In view of the great diversity of mostly yet-uncultured bacteria and the considerable differences between individual toilets, very general strategies appear to be most suited for the removal and prevention of toilet biofilms. SIGNIFICANCE AND IMPACT OF THE STUDY: For the first time, a molecular fingerprinting and cloning approach was used to monitor the species composition in biofilm samples taken from domestic toilets. Knowledge about the microbial composition of biofilms in domestic toilets is a prerequisite for developing and evaluating strategies for their removal and prevention.


Assuntos
Fenômenos Fisiológicos Bacterianos , Biodiversidade , Biofilmes , Banheiros , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Filogenia , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/genética
17.
Biomacromolecules ; 10(6): 1346-57, 2009 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-19425547

RESUMO

We use small angle neutron scattering (SANS), with an original analysis method, to obtain both the characteristic sizes and the inner composition of lysozyme-pectin complexes depending on the charge density. Lysozyme is a globular protein and pectin a natural anionic semiflexible polysaccharide with a degree of methylation (DM) 0, 43, and 74. For our experimental conditions (buffer ionic strength I = 2.5 10(-2) mol/L and pH between 3 and 7), the electrostatic charge of lysozyme is always positive (from 8 to 17, depending on pH). The pectin charge per elementary chain segment is negative and can be varied from almost zero to one through the change of DM and pH. The weight molar ratio of lysozyme on pectin monomers is kept constant. The ratio of negative charge content per volume to positive charge content per volume, -/+, is varied between 10 and 0.007. On a local scale, for all charged pectins, a correlation peak appears at 0.2 A(-1) due to proteins clustering inside the complexes. On a large scale, the complexes appear as formed of spherical globules with a well-defined radius of 10 to 50 nm, containing a few thousands proteins. The volume fraction Phi of organic matter within the globules derived from SANS absolute cross sections is around 0.1. The protein stacking, which occurs inside the globules, is enhanced when pectin is more charged, due to pH or DM. The linear charge density of the pectin determines the size of the globules for pectin chains of comparable molecular weights whether it is controlled by the pH or the DM. The radius of the globules varies between 10 and 50 nm. In conclusion, the structure is driven by electrostatic interactions and not by hydrophobic interactions. The molecular weight also has a large influence on the structure of the complexes because long chains tend to form larger globules. This may be one reason why DM and pH are not completely equivalent in our system, because DM0 has a short mass, but this may not be the only one. For very low pectin charge (-/+ = 0.07), globules do not appear and the scattering signals a gel-like structure. We did not observe any beads-on-a-string structure.


Assuntos
Muramidase/química , Nêutrons , Pectinas/química , Concentração de Íons de Hidrogênio , Espalhamento de Radiação
18.
Plant Biol (Stuttg) ; 21(3): 389-397, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-29779253

RESUMO

Large-scale restoration programmes in the tropics require large volumes of high quality, genetically diverse and locally adapted seeds from a large number of species. However, scarcity of native seeds is a critical restriction to achieve restoration targets. In this paper, we analyse three successful community-based networks that supply native seeds and seedlings for Brazilian Amazon and Cerrado restoration projects. In addition, we propose directions to promote local participation, legal, technical and commercialisation issues for up-scaling the market of native seeds for restoration with high quality and social justice. We argue that effective community-based restoration arrangements should follow some principles: (i) seed production must be based on real market demand; (ii) non-governmental and governmental organisations have a key role in supporting local organisation, legal requirements and selling processes; (iii) local ecological knowledge and labour should be valued, enabling local communities to promote large-scale seed production; (iv) applied research can help develop appropriate techniques and solve technical issues. The case studies from Brazil and principles presented here can be useful for the up-scaling restoration ecology efforts in many other parts of the world and especially in tropical countries where improving rural community income is a strategy for biodiversity conservation and restoration.


Assuntos
Sementes , Biodiversidade , Brasil , Conservação dos Recursos Naturais , Ecologia
19.
Clin Exp Allergy ; 38(1): 93-102, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18028460

RESUMO

BACKGROUND: Probiotic bacteria are proposed to alleviate atopic dermatitis (AD) in infants. There are few indications about the effect of probiotics on AD in adults. OBJECTIVE: The purpose of this study was to elucidate the influence of a probiotic drink containing a combination of the probiotics Lactobacillus paracasei Lpc-37, Lactobacillus acidophilus 74-2 and Bifidobacterium animalis subsp. lactis DGCC 420 (B. lactis 420) in healthy volunteers and in patients with AD on clinical and immunological parameters and their detection in feces. METHODS: A double-blind, placebo-controlled, randomized cross-over study was conducted in 15 healthy adults and 15 patients with AD. The probiotic product or placebo was given over 8 weeks. A 2-week washout period was interconnected before the intervention was crossed. At the end of each period, blood and stool samples were collected. In patients, the severity of AD was evaluated using the Scoring of Atopic Dermatitis (SCORAD). RESULTS: L. paracasei and B. lactis were recovered in high numbers in feces after supplementation, whereas L. acidophilus marginally increased. In patients, the SCORAD tended to decrease by 15.5% (P=0.081). Major lymphocyte subsets were not affected by the probiotic intervention. However, CD57(+) increased significantly (P=0.034) in healthy subjects after probiotic intake and was not changed in patients, whereas CD4(+)CD54(+) decreased significantly (P=0.031) in patients with AD and remained uninfluenced in healthy subjects. The expression of CD4(+)CD25(+) T cells was similar in healthy subjects and AD patients. The phagocytic activity of monocytes and granulocytes was significantly increased in healthy subjects after probiotic intervention (P=0.014). CONCLUSION: L. paracasei Lpc-37 and B. lactis 420 are able to colonize the intestine transiently. This study reveals that the probiotics differently modulate peripheral immune parameters in healthy subjects and patients with AD.


Assuntos
Dermatite Atópica/imunologia , Saúde , Probióticos , Adulto , Formação de Anticorpos/imunologia , Bifidobacterium , Dermatite Atópica/microbiologia , Fezes/microbiologia , Feminino , Humanos , Imunoglobulina E/sangue , Imunoglobulina E/imunologia , Lactobacillus , Linfócitos/imunologia , Masculino
20.
Sci Total Environ ; 407(1): 692-7, 2008 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-18930514

RESUMO

The global climate is predicted to become significantly warmer over the next century. This will affect ecosystem processes and the functioning of semi natural and natural ecosystems in many parts of the world. However, as various ecosystem processes may be affected to a different extent, balances between different ecosystem processes as well as between different ecosystems may shift and lead to major unpredicted changes. In this study four European shrubland ecosystems along a north-south temperature gradient were experimentally warmed by a novel nighttime warming technique. Biogeochemical cycling of both carbon and nitrogen was affected at the colder sites with increased carbon uptake for plant growth as well as increased carbon loss through soil respiration. Carbon uptake by plant growth was more sensitive to warming than expected from the temperature response across the sites while carbon loss through soil respiration reacted to warming in agreement with the overall Q10 and response functions to temperature across the sites. Opposite to carbon, the nitrogen mineralization was relatively insensitive to the temperature increase and was mainly affected by changes in soil moisture. The results suggest that C and N cycles respond asymmetrically to warming, which may lead to progressive nitrogen limitation and thereby acclimation in plant production. This further suggests that in many temperate zones nitrogen deposition has to be accounted for, not only with respect to the impact on water quality through increased nitrogen leaching where N deposition is high, but also in predictions of carbon sequestration in terrestrial ecosystems under future climatic conditions. Finally the results indicate that on the short term the above-ground processes are more sensitive to temperature changes than the below ground processes.


Assuntos
Carbono/análise , Ecossistema , Monitoramento Ambiental/métodos , Efeito Estufa , Nitrogênio/análise , Europa (Continente) , Desenvolvimento Vegetal , Solo/análise , Solo/normas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA