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1.
Plant Cell ; 33(7): 2296-2319, 2021 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-34009390

RESUMO

Flower development is an important determinant of grain yield in crops. In wheat (Triticum spp.), natural variation for the size of spikelet and floral organs is particularly evident in Triticum turgidum ssp. polonicum (also termed Triticum polonicum), a tetraploid subspecies of wheat with long glumes, lemmas, and grains. Using map-based cloning, we identified VEGETATIVE TO REPRODUCTIVE TRANSITION 2 (VRT2), which encodes a MADS-box transcription factor belonging to the SHORT VEGETATIVE PHASE family, as the gene underlying the T. polonicum long-glume (P1) locus. The causal P1 mutation is a sequence rearrangement in intron-1 that results in ectopic expression of the T. polonicum VRT-A2 allele. Based on allelic variation studies, we propose that the intron-1 mutation in VRT-A2 is the unique T. polonicum subspecies-defining polymorphism, which was later introduced into hexaploid wheat via natural hybridizations. Near-isogenic lines differing for the P1 locus revealed a gradient effect of P1 across spikelets and within florets. Transgenic lines of hexaploid wheat carrying the T. polonicum VRT-A2 allele show that expression levels of VRT-A2 are highly correlated with spike, glume, grain, and floral organ length. These results highlight how changes in expression profiles, through variation in cis-regulation, can affect agronomic traits in a dosage-dependent manner in polyploid crops.


Assuntos
Poliploidia , Triticum/genética , Expressão Ectópica do Gene/genética , Expressão Ectópica do Gene/fisiologia , Flores/genética , Flores/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Genes de Plantas/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
2.
New Phytol ; 240(1): 224-241, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37424336

RESUMO

The determination of starch granule morphology in plants is poorly understood. The amyloplasts of wheat endosperm contain large discoid A-type granules and small spherical B-type granules. To study the influence of amyloplast structure on these distinct morphological types, we isolated a mutant in durum wheat (Triticum turgidum) defective in the plastid division protein PARC6, which had giant plastids in both leaves and endosperm. Endosperm amyloplasts of the mutant contained more A- and B-type granules than those of the wild-type. The mutant had increased A- and B-type granule size in mature grains, and its A-type granules had a highly aberrant, lobed surface. This morphological defect was already evident at early stages of grain development and occurred without alterations in polymer structure and composition. Plant growth and grain size, number and starch content were not affected in the mutants despite the large plastid size. Interestingly, mutation of the PARC6 paralog, ARC6, did not increase plastid or starch granule size. We suggest TtPARC6 can complement disrupted TtARC6 function by interacting with PDV2, the outer plastid envelope protein that typically interacts with ARC6 to promote plastid division. We therefore reveal an important role of amyloplast structure in starch granule morphogenesis in wheat.


Assuntos
Endosperma , Triticum , Endosperma/genética , Endosperma/metabolismo , Triticum/genética , Triticum/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Amido/metabolismo , Plastídeos/genética , Plastídeos/metabolismo , Mutação/genética
3.
J Exp Bot ; 73(18): 6367-6379, 2022 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-35716106

RESUMO

Recent work has identified several proteins involved in starch granule initiation, the first step of starch synthesis. However, the degree of conservation in the granule initiation process remains poorly understood, especially among grass species differing in patterns of carbohydrate turnover in leaves, and granule morphology in the endosperm. We therefore compared mutant phenotypes of Hordeum vulgare (barley), Triticum turgidum (durum wheat), and Brachypodium distachyon defective in PROTEIN TARGETING TO STARCH 2 (PTST2), a key granule initiation protein. We report striking differences across species and organs. Loss of PTST2 from leaves resulted in fewer, larger starch granules per chloroplast and normal starch content in wheat, fewer granules per chloroplast and lower starch content in barley, and almost complete loss of starch in Brachypodium. The loss of starch in Brachypodium leaves was accompanied by high levels of ADP-glucose and detrimental effects on growth and physiology. Additionally, we found that loss of PTST2 increased granule initiation in Brachypodium amyloplasts, resulting in abnormal compound granule formation throughout the seed. These findings suggest that the importance of PTST2 varies greatly with the genetic and developmental background and inform the extent to which the gene can be targeted to improve starch in crops.


Assuntos
Brachypodium , Hordeum , Sintase do Amido , Amido/metabolismo , Sintase do Amido/genética , Endosperma/metabolismo , Hordeum/genética , Hordeum/metabolismo , Triticum/genética , Triticum/metabolismo , Glucose/metabolismo , Difosfato de Adenosina/metabolismo
4.
New Phytol ; 230(6): 2371-2386, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33714222

RESUMO

Starch granule initiation is poorly understood at the molecular level. The glucosyltransferase, STARCH SYNTHASE 4 (SS4), plays a central role in granule initiation in Arabidopsis leaves, but its function in cereal endosperms is unknown. We investigated the role of SS4 in wheat, which has a distinct spatiotemporal pattern of granule initiation during grain development. We generated TILLING mutants in tetraploid wheat (Triticum turgidum) that are defective in both SS4 homoeologs. The morphology of endosperm starch was examined in developing and mature grains. SS4 deficiency led to severe alterations in endosperm starch granule morphology. During early grain development, while the wild-type initiated single 'A-type' granules per amyloplast, most amyloplasts in the mutant formed compound granules due to multiple initiations. This phenotype was similar to mutants deficient in B-GRANULE CONTENT 1 (BGC1). SS4 deficiency also reduced starch content in leaves and pollen grains. We propose that SS4 and BGC1 are required for the proper control of granule initiation during early grain development that leads to a single A-type granule per amyloplast. The absence of either protein results in a variable number of initiations per amyloplast and compound granule formation.


Assuntos
Sintase do Amido , Endosperma/genética , Proteínas de Plantas/genética , Plastídeos/genética , Amido , Sintase do Amido/genética , Triticum/genética
5.
J Biol Chem ; 291(41): 21531-21540, 2016 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-27531751

RESUMO

GlgE is a maltosyltransferase involved in α-glucan biosynthesis in bacteria that has been genetically validated as a target for tuberculosis therapies. Crystals of the Mycobacterium tuberculosis enzyme diffract at low resolution so most structural studies have been with the very similar Streptomyces coelicolor GlgE isoform 1. Although the donor binding site for α-maltose 1-phosphate had been previously structurally defined, the acceptor site had not. Using mutagenesis, kinetics, and protein crystallography of the S. coelicolor enzyme, we have now identified the +1 to +6 subsites of the acceptor/product, which overlap with the known cyclodextrin binding site. The sugar residues in the acceptor subsites +1 to +5 are oriented such that they disfavor the binding of malto-oligosaccharides that bear branches at their 6-positions, consistent with the known acceptor chain specificity of GlgE. A secondary binding site remote from the catalytic center was identified that is distinct from one reported for the M. tuberculosis enzyme. This new site is capable of binding a branched α-glucan and is most likely involved in guiding acceptors toward the donor site because its disruption kinetically compromises the ability of GlgE to extend polymeric substrates. However, disruption of this site, which is conserved in the Streptomyces venezuelae GlgE enzyme, did not affect the growth of S. venezuelae or the structure of the polymeric product. The acceptor subsites +1 to +4 in the S. coelicolor enzyme are well conserved in the M. tuberculosis enzyme so their identification could help inform the design of inhibitors with therapeutic potential.


Assuntos
Proteínas de Bactérias/química , Glucosiltransferases/química , Streptomyces coelicolor/enzimologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Glucosiltransferases/genética , Glucosiltransferases/metabolismo , Mutagênese Sítio-Dirigida , Mycobacterium tuberculosis/enzimologia , Mycobacterium tuberculosis/genética , Streptomyces coelicolor/genética
6.
Biochemistry ; 55(23): 3270-84, 2016 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-27221142

RESUMO

Actinomycetes, such as mycobacteria and streptomycetes, synthesize α-glucan with α-1,4 linkages and α-1,6 branching to help evade immune responses and to store carbon. α-Glucan is thought to resemble glycogen except for having shorter constituent linear chains. However, the fine structure of α-glucan and how it can be defined by the maltosyl transferase GlgE and branching enzyme GlgB were not known. Using a combination of enzymolysis and mass spectrometry, we compared the properties of α-glucan isolated from actinomycetes with polymer synthesized in vitro by GlgE and GlgB. We now propose the following assembly mechanism. Polymer synthesis starts with GlgE and its donor substrate, α-maltose 1-phosphate, yielding a linear oligomer with a degree of polymerization (∼16) sufficient for GlgB to introduce a branch. Branching involves strictly intrachain transfer to generate a C chain (the only constituent chain to retain its reducing end), which now bears an A chain (a nonreducing end terminal branch that does not itself bear a branch). GlgE preferentially extends A chains allowing GlgB to act iteratively to generate new A chains emanating from B chains (nonterminal branches that themselves bear a branch). Although extension and branching occur primarily with A chains, the other chain types are sometimes extended and branched such that some B chains (and possibly C chains) bear more than one branch. This occurs less frequently in α-glucans than in classical glycogens. The very similar properties of cytosolic and capsular α-glucans from Mycobacterium tuberculosis imply GlgE and GlgB are sufficient to synthesize them both.


Assuntos
Glucanos/química , Glucanos/metabolismo , Glucosiltransferases/metabolismo , Mycobacterium/metabolismo , Streptomycetaceae/metabolismo , Fosfatos Açúcares/metabolismo , Eletroforese Capilar , Espectroscopia de Ressonância Magnética , Mycobacterium/classificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
7.
Microbiology (Reading) ; 162(7): 1208-1219, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27121970

RESUMO

The GlgE pathway is thought to be responsible for the conversion of trehalose into a glycogen-like α-glucan polymer in bacteria. Trehalose is first converted to maltose, which is phosphorylated by maltose kinase Pep2 to give α-maltose 1-phosphate. This is the donor substrate of the maltosyl transferase GlgE that is known to extend α-1,4-linked maltooligosaccharides, which are thought to be branched with α-1,6 linkages. The genome of Streptomyces venezuelae contains all the genes coding for the GlgE pathway enzymes but none of those of related pathways, including glgC and glgA of the glycogen pathway. This provides an opportunity to study the GlgE pathway in isolation. The genes of the GlgE pathway were upregulated at the onset of sporulation, consistent with the known timing of α-glucan deposition. A constructed ΔglgE null mutant strain was viable but showed a delayed developmental phenotype when grown on maltose, giving less cell mass and delayed sporulation. Pre-spore cells and spores of the mutant were frequently double the length of those of the wild-type, implying impaired cross-wall formation, and spores showed reduced tolerance to stress. The mutant accumulated α-maltose 1-phosphate and maltose but no α-glucan. Therefore, the GlgE pathway is necessary and sufficient for polymer biosynthesis. Growth of the ΔglgE mutant on galactose and that of a Δpep2 mutant on maltose were analysed. In both cases, neither accumulation of α-maltose 1-phosphate/α-glucan nor a developmental delay was observed. Thus, high levels of α-maltose 1-phosphate are responsible for the developmental phenotype of the ΔglgE mutant, rather than the lack of α-glucan.


Assuntos
Glucanos/metabolismo , Glucosiltransferases/genética , Esporos Bacterianos/crescimento & desenvolvimento , Streptomyces/crescimento & desenvolvimento , Fosfatos Açúcares/metabolismo , Glicogênio/metabolismo , Maltose/metabolismo , Oligossacarídeos/metabolismo , Esporos Bacterianos/genética , Streptomyces/genética , Trealose/metabolismo
8.
Qual Life Res ; 23(5): 1603-7, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24307212

RESUMO

PURPOSE: To assess the feasibility of collecting patient-reported outcomes data with wireless touch screen tablet computers in the adult oncology palliative care setting. METHODS: Patients were provided with tablet computers during scheduled clinic visits and answered online queries about their experience over the past week in the health domains of anxiety, depression, fatigue, pain interference, physical function, instrumental social support, sleep impairment, diarrhea, constipation, nausea, vomiting, anorexia, dyspnea, neuropathy, and spiritual values. RESULTS: Content analysis of patient interviews indicates that wireless touch screen tablet computers are a feasible approach for collecting patient-reported outcome measures by palliative care cancer patients presenting in clinic. Most patients indicated that the questionnaire was easy to answer. However, all but one patient requested some form of assistance, and many reported difficulties attributable to a lack of familiarity with the device, interpretation of certain questions, and wireless connectivity-related issues. CONCLUSIONS: This feasibility study demonstrates that tablet computers have the potential to efficiently and reliably collect patient-reported health status measures among palliative care cancer patients presenting in clinics. The use of these devices may lead to substantial improvements by making patient-reported outcomes available for clinical decision-making.


Assuntos
Neoplasias/psicologia , Avaliação de Resultados da Assistência ao Paciente , Psicometria/instrumentação , Perfil de Impacto da Doença , Adulto , Algoritmos , Protocolos Clínicos , Desenho Assistido por Computador , Estudos de Viabilidade , Humanos , Entrevistas como Assunto , Estadiamento de Neoplasias , Neoplasias/complicações , Cuidados Paliativos/normas , Psicometria/métodos , Reprodutibilidade dos Testes , Software , Inquéritos e Questionários , Virginia , Tecnologia sem Fio/estatística & dados numéricos
9.
Science ; 380(6651): 1275-1281, 2023 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-37347863

RESUMO

Growth coordination between cell layers is essential for development of most multicellular organisms. Coordination may be mediated by molecular signaling and/or mechanical connectivity between cells, but how genes modify mechanical interactions between layers is unknown. Here we show that genes driving brassinosteroid synthesis promote growth of internal tissue, at least in part, by reducing mechanical epidermal constraint. We identified a brassinosteroid-deficient dwarf mutant in the aquatic plant Utricularia gibba with twisted internal tissue, likely caused by mechanical constraint from a slow-growing epidermis. We tested this hypothesis by showing that a brassinosteroid mutant in Arabidopsis enhances epidermal crack formation, indicative of increased tissue stress. We propose that by remodeling cell walls, brassinosteroids reduce epidermal constraint, showing how genes can control growth coordination between layers by means of mechanics.


Assuntos
Brassinosteroides , Lamiales , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Brassinosteroides/biossíntese , Comunicação Celular , Parede Celular/metabolismo , Lamiales/citologia , Lamiales/genética , Lamiales/metabolismo , Epiderme Vegetal/metabolismo
10.
Front Physiol ; 13: 862189, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35733992

RESUMO

This study was undertaken to determine if fiber arrangement was responsible for differences in the whole muscle mechanical properties. Experiments were carried out in situ in blood perfused dog skeletal muscles at approximately normal body temperature between 36° and 38°C. The following mechanical relationships were studied using a pneumatic muscle lever to measure Tension (P), length (L) and dP/dt: and dL/dt with a high frequency oscillograph (500-1000 Hz): 1.) Length:Tension; 2.) Force:Velocity; and 3.) Stress:Strain of Series Elastic. Electron microscopy and fiber typing were done as adjunctive studies. Muscles were stimulated by direct nerve stimulation with 0.1msec stimuli at a rate of 1 impulse per second for twitch contractions, or in 200 msec bursts of 100 Hz 0.1 msec stimuli for brief tetanic contractions. The pennate short fibered gastrocnemius plantaris developed 1.0 kg/g of tension during brief tetanic stimulation, at optimal length (Lo) with full stimulus voltage, while the parallel long fibered semitendinosus developed 0.5 kg/g under the same conditions. The Length:Tension relationship for these two muscles was qualitatively similar but quantitatively different. The Force:Velocity relationship (ΔL/L0 vs. P/P0) for both muscles were also qualitatively similar and could be described by the previously proposed rectangular hyperbola but a better predicted fit to the observed data could be produced by adding a descending exponential function to the rectangular hyperbola. Unlike previous studies, the Stress:Strain properties of the series elastic component measured by quick release (ΔL/Li vs. ΔP/Po) were linear and gastrocnemius was 25 per cent higher than the semitendinosus. Overall, both muscles were found to have mechanical properties that differed little from the previously reported literature for amphibian, cardiac and small mammalian muscles studied by others in vitro. The major differences that we found were in the shapes of the force:velocity curve of the contractile component, and the Stress:Strain curve of series elastic component. Equations and explanations for these differences are devised and presented.

11.
FEMS Microbiol Lett ; 369(1)2022 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-35323924

RESUMO

Ammonia-oxidising archaea (AOA) are environmentally important microorganisms involved in the biogeochemical cycling of nitrogen. Routine cultivation of AOA is exclusively performed in liquid cultures and reports on their growth on solid medium are scarce. The ability to grow AOA on solid medium would be beneficial for not only the purification of enrichment cultures but also for developing genetic tools. The aim of this study was to develop a reliable method for growing individual colonies from AOA cultures on solid medium. Three phylogenetically distinct AOA strains were tested: 'Candidatus Nitrosocosmicus franklandus C13', Nitrososphaera viennensis EN76 and 'Candidatus Nitrosotalea sinensis Nd2'. Of the gelling agents tested, agar and Bacto-agar severely inhibited growth of all three strains. In contrast, both 'Ca. N. franklandus C13' and N. viennensis EN76 tolerated Phytagel™ while the acidophilic 'Ca. N. sinensis Nd2' was completely inhibited. Based on these observations, we developed a Liquid-Solid (LS) method that involves immobilising cells in Phytagel™ and overlaying with liquid medium. This approach resulted in the development of visible distinct colonies from 'Ca. N. franklandus C13' and N. viennensis EN76 cultures and lays the groundwork for the genetic manipulation of this group of microorganisms.


Assuntos
Amônia , Archaea , Ágar , Archaea/genética , Meios de Cultura , Nitrificação , Oxirredução , Filogenia , Microbiologia do Solo
12.
Nat Commun ; 13(1): 4129, 2022 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-35840594

RESUMO

A critical challenge during volcanic emergencies is responding to rapid changes in eruptive behaviour. Actionable advice, essential in times of rising uncertainty, demands the rapid synthesis and communication of multiple datasets with prognoses. The 2020-2021 eruption of La Soufrière volcano exemplifies these challenges: a series of explosions from 9-22 April 2021 was preceded by three months of effusive activity, which commenced with a remarkably low level of detected unrest. Here we show how the development of an evolving conceptual model, and the expression of uncertainties via both elicitation and scenarios associated with this model, were key to anticipating this transition. This not only required input from multiple monitoring datasets but contextualisation via state-of-the-art hazard assessments, and evidence-based knowledge of critical decision-making timescales and community needs. In addition, we share strategies employed as a consequence of constraints on recognising and responding to eruptive transitions in a resource-constrained setting, which may guide similarly challenged volcano observatories worldwide.


Assuntos
Desastres , Erupções Vulcânicas
13.
JCI Insight ; 7(23)2022 12 08.
Artigo em Inglês | MEDLINE | ID: mdl-36477361

RESUMO

NK cell deficiencies (NKD) are a type of primary immune deficiency in which the major immunologic abnormality affects NK cell number, maturity, or function. Since NK cells contribute to immune defense against virally infected cells, patients with NKD experience higher susceptibility to chronic, recurrent, and fatal viral infections. An individual with recurrent viral infections and mild hypogammaglobulinemia was identified to have an X-linked damaging variant in the transcription factor gene ELF4. The variant does not decrease expression but disrupts ELF4 protein interactions and DNA binding, reducing transcriptional activation of target genes and selectively impairing ELF4 function. Corroborating previous murine models of ELF4 deficiency (Elf4-/-) and using a knockdown human NK cell line, we determined that ELF4 is necessary for normal NK cell development, terminal maturation, and function. Through characterization of the NK cells of the proband, expression of the proband's variant in Elf4-/- mouse hematopoietic precursor cells, and a human in vitro NK cell maturation model, we established this ELF4 variant as a potentially novel cause of NKD.


Assuntos
Fatores de Transcrição , Animais , Humanos , Camundongos , Proteínas de Ligação a DNA/genética , Células Matadoras Naturais , Fatores de Transcrição/genética
14.
R Soc Open Sci ; 8(1): 201566, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33614088

RESUMO

Personal contacts drive COVID-19 infections. After being closed (23 March 2020) UK primary schools partially re-opened on 1 June 2020 with social distancing and new risk mitigation strategies. We conducted a structured expert elicitation of teachers to quantify primary school contact patterns and how contact rates changed upon re-opening with risk mitigation measures in place. These rates, with uncertainties, were determined using a performance-based algorithm. We report mean number of contacts per day for four cohorts within schools, with associated 90% confidence ranges. Prior to lockdown, younger children (Reception and Year 1) made 15 contacts per day [range 8.35] within school, older children (Year 6) 18 contacts [range 5.55], teaching staff 25 contacts [range 4.55] and non-classroom staff 11 contacts [range 2.27]. After re-opening, the mean number of contacts was reduced by 53% for young children, 62% for older children, 60% for classroom staff and 64% for other staff. Contacts between teaching and non-teaching staff reduced by 80%. The distributions of contacts per person are asymmetric with heavy tail reflecting a few individuals with high contact numbers. Questions on risk mitigation and supplementary structured interviews elucidated how new measures reduced daily contacts in-school and contribute to infection risk reduction.

15.
Brain ; 132(Pt 5): 1324-34, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19321462

RESUMO

Deposits of abnormally phosphorylated tau protein are found in numerous neurodegenerative disorders; the 'tauopathies', which include Alzheimer's and Pick's diseases, but tau pathology is also found in the ageing brain. Variation in tau pathology in brain ageing and its relationship to development of tauopathies and cognitive impairment remains unclear. We aimed to determine the extent and pattern of spread of tau pathology in the hippocampus, a susceptible region important in dementia and milder states of memory impairment, using hippocampal samples from the elderly population-based Medical Research Council Cognitive Function and Ageing Study neuropathology cohort. Tau deposition was assessed in hippocampal anatomical sub-regions using the AT8 antibody to phosphorylated tau and isoform-specific antibodies to 3 and 4-repeat tau (RD3 and RD4). Abeta pathology was also assessed. In this population sample, which includes the full ageing spectrum from individuals with no cognitive impairment to those with dementia satisfying clinico-pathology criteria for Alzheimer's disease, we have demonstrated a high prevalence at death of tau pathology. AT8, Abeta, RD3 and RD4 showed similar regional distribution and increased RD3 was noted in late-stage ghost tangles. Abeta was shown to be a poor explanatory variable for tau pathology. Tau deposition progressed in a hierarchical manner. Hippocampal input regions and projection zones (such as lateral entorhinal cortex, CA1/subiculum border and outer molecular layer of dentate) were initially affected, with anterograde progression though the hippocampal circuitry. Six hippocampal tau anatomical stages were defined, each linking projectionally to their adjacent stages, suggesting spread of tau malfunction through neuroanatomical pathways in hippocampal ageing. These stages were significantly associated with dementia, and may provide a clinically useful tool in the clinico-pathological assessment of dementia and mild cognitive impairment.


Assuntos
Envelhecimento/metabolismo , Doença de Alzheimer/metabolismo , Hipocampo/química , Proteínas tau/análise , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/patologia , Envelhecimento/psicologia , Doença de Alzheimer/patologia , Doença de Alzheimer/psicologia , Peptídeos beta-Amiloides/análise , Peptídeos beta-Amiloides/metabolismo , Distribuição de Qui-Quadrado , Cognição , Progressão da Doença , Córtex Entorrinal/química , Córtex Entorrinal/metabolismo , Córtex Entorrinal/patologia , Feminino , Hipocampo/metabolismo , Hipocampo/patologia , Humanos , Imuno-Histoquímica , Estudos Longitudinais , Masculino , Vias Neurais/fisiologia , Proteínas tau/metabolismo
16.
Mol Biol Cell ; 31(10): 981-991, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32352896

RESUMO

Lymphocyte development is a complex and coordinated pathway originating from pluripotent stem cells during embryogenesis and continuing even as matured lymphocytes are primed and educated in adult tissue. Hematopoietic stem cells develop in a specialized niche that includes extracellular matrix and supporting stromal and endothelial cells that both maintain stem cell pluripotency and enable the generation of differentiated cells. Cues for lymphocyte development include changes in integrin-dependent cell motility and adhesion which ultimately help to determine cell fate. The capacity of lymphocytes to adhere and migrate is important for modulating these developmental signals both by regulating the cues that the cell receives from the local microenvironment as well as facilitating the localization of precursors to tissue niches throughout the body. Here we consider how changing migratory and adhesive phenotypes contribute to human natural killer (NK)- and T-cell development as they undergo development from precursors to mature, circulating cells and how our understanding of this process is informed by in vitro models of T- and NK cell generation.


Assuntos
Movimento Celular , Polaridade Celular , Células-Tronco Hematopoéticas/citologia , Células Matadoras Naturais/citologia , Linfócitos T/citologia , Animais , Adesão Celular , Humanos
17.
J Leukoc Biol ; 108(4): 1369-1378, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32392635

RESUMO

Human NK cells are effectors of the innate immune system that originate from hematopoietic precursors in the bone marrow. While stromal cell lines that support NK cell development from hematopoietic precursors are often used to generate mature NK cells from lymphoid precursors in vitro, the nature of contributing factors of these stromal cells to the generation of functionally mature NK cells has been poorly described. Previous studies have shown that developing NK cells adhere to, and migrate on, developmentally supportive stroma. Here, we describe the generation of cell-derived matrices (CDMs) from a commonly used murine fetal liver stromal cell line. These CDMs are derived directly from the same EL08.1D2 stromal cell line known to support NK cell differentiation and contain ECM structural components fibronectin and collagen. We demonstrate that CDMs support NK cell adhesion and migration with similar properties as intact cells. Further, we show that CDMs support NK cell maturation from lymphoid precursors in vitro, albeit with reduced cell survival compared to intact cell-based differentiation. Together, these results describe a cell-free system that supports NK cell development and that can serve as a useful model for studying the nature of the biochemical interactions between NK cell developmental intermediates and developmentally supportive substrates.


Assuntos
Diferenciação Celular/imunologia , Movimento Celular/imunologia , Matriz Extracelular/imunologia , Células Matadoras Naturais/imunologia , Modelos Imunológicos , Linhagem Celular , Humanos
18.
Occup Environ Med ; 66(5): 325-34, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19017697

RESUMO

OBJECTIVES: To investigate preclinical adverse effects of ambient particulate air pollution and nitrogen oxides in patients with heart failure. METHODS: A cohort of 132 non-smoking patients living in Aberdeen, Scotland, with stable chronic heart failure were enrolled in a repeated-measures panel study. Patients with atrial fibrillation or pacemakers were excluded. Participants were studied for 3 days every 2 months for up to 1 year with monitoring of pollutant exposure and concurrent measurements of pathophysiological responses. Measurements included daily area concentration of particulate matter with a median aerodynamic diameter of <10 micrometres (PM(10)), particle number concentration (PNC) and nitrogen oxides; daily estimated personal concentration of particulate matter with a median aerodynamic diameter of <2.5 micrometres (PM(2.5)) and PNC exposures; and 3-day cumulative personal nitrogen dioxide (NO(2)). Concurrent meteorological data were recorded. Blood was taken at the end of each 3-day block for assays of markers of endothelial activation, inflammation and coagulation. Cardiac rhythm was monitored by ambulatory Holter monitor during the final 24 h of each block. RESULTS: The average 24 h background ambient PM(10) ranged from 7.4 to 68 microg.m(-3) and PNC from 454 to 11 283 particles.cm(-3). No associations were demonstrated between the incidence of arrhythmias, heart rate variability or haematological/biochemical measures and any variations in pollutant exposures at any lags. CONCLUSION: Assuming that low-level pollution affects the parameters measured, these findings may suggest a beneficial effect of modern cardioprotective therapy, which may modify responses to external risk factors. Widespread use of such drugs in susceptible populations may in future reduce the adverse effects of air pollution on the heart.


Assuntos
Poluentes Atmosféricos/efeitos adversos , Poluição do Ar/efeitos adversos , Arritmias Cardíacas/induzido quimicamente , Exposição por Inalação/efeitos adversos , Óxidos de Nitrogênio/efeitos adversos , Material Particulado/efeitos adversos , Idoso , Poluição do Ar/estatística & dados numéricos , Arritmias Cardíacas/epidemiologia , Biomarcadores/metabolismo , Feminino , Insuficiência Cardíaca/induzido quimicamente , Insuficiência Cardíaca/epidemiologia , Frequência Cardíaca/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Monitorização Ambulatorial , Escócia/epidemiologia
19.
Carbohydr Polym ; 223: 115044, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31427007

RESUMO

Inulin nanoparticles (INNPs) are a biocompatible material which has a potential application for enhancing solubility and preventing degradation of compounds. In this work, we demonstrated that INNPs could be synthesized from sucrose using inulosucrase from Lactobacillus reuteri 121. Noticeably, dynamic light scattering (DLS) analysis showed that the derived INNPs exhibited uniformity in size, which was easily controlled by the reaction temperature. The effect of enzyme and sucrose concentration, as well as reaction time, was explored. Moreover, the solubility of INNPs in various organic solvents was also investigated, and we found that the INNPs were freely regenerated in water even though they had precipitated by organic solvents. Essentially, we demonstrated that the derived INNPs could be applied for flavonoid encapsulation. The solubility and stability of quercetin and fisetin in the INNPs complexes was higher than those of free compounds. These results make the INNPs very promising for many applications.


Assuntos
Flavonoides/química , Hexosiltransferases/metabolismo , Inulina/biossíntese , Limosilactobacillus reuteri/enzimologia , Nanopartículas/química , Quercetina/química , Flavonóis , Concentração de Íons de Hidrogênio , Inulina/química , Tamanho da Partícula , Solubilidade , Temperatura
20.
J Parasitol ; 93(6): 1529-30, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18314707

RESUMO

The range-wide population of American woodcock Scolopax minor has been in slow, steady decline since the late 1960s. The parasite load carried by woodcock and its possible role in the population decline has not been investigated since the early 1970s. A survey of parasites in American woodcock in Connecticut was undertaken in 2002: Sarcocystis spp. was found in 32 of 78 (42%) individuals examined. Elongate sarcocysts, 25 x 125 micro, containing numerous packed bradyzoites with distinct, tightly packed villar projections of the cyst wall, were found scattered throughout skeletal type and myocardial muscle. Sarcocystis spp. was also recorded during the earlier surveys and considered common, but was not examined with the use of electron microscopy. The present study includes the first ultrastructural description of Sarcocystis sp. in the skeletal muscle of woodcock and will serve as a basis for future comparisons in woodcock.


Assuntos
Doenças das Aves/parasitologia , Charadriiformes/parasitologia , Sarcocystis/ultraestrutura , Sarcocistose/veterinária , Fatores Etários , Animais , Doenças das Aves/epidemiologia , Connecticut/epidemiologia , Feminino , Masculino , Microscopia Eletrônica de Transmissão/veterinária , Músculo Esquelético/parasitologia , Prevalência , Sarcocystis/isolamento & purificação , Sarcocistose/epidemiologia , Sarcocistose/parasitologia
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