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1.
J Biol Chem ; 300(1): 105552, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38072065

RESUMO

Fibrinogen C domain-containing protein 1 (FIBCD1) is an immune protein proposed to be involved in host recognition of chitin on the surface of pathogens. As FIBCD1 readily binds acetylated molecules, we have determined the high-resolution crystal structures of a recombinant fragment of the FIBCD1 C-terminal domain complexed with small N-acetyl-containing ligands to determine the mode of recognition. All ligands bind at the conserved N-acetyl-binding site (S1) with galactose and glucose-derived ligands rotated 180° relative to each other. One subunit of a native structure derived from protein expressed in mammalian cells binds glycosylation from a neighboring subunit, in an extended binding site. Across the various structures, the primary S1 binding pocket is occupied by N-acetyl-containing ligands or acetate, with N-acetyl, acetate, or sulfate ion in an adjacent pocket S1(2). Inhibition binding studies of N-acetylglucosamine oligomers, (GlcNAc)n, n = 1, 2, 3, 5, 11, via ELISA along with microscale thermophoresis affinity assays indicate a strong preference of FIBCD1 for longer N-acetylchitooligosaccharides. Binding studies of mutant H396A, located beyond the S1(2) site, showed no significant difference from wildtype, but K381L, within the S1(2) pocket, blocked binding to the model ligand acetylated bovine serum albumin, suggesting that S1(2) may have functional importance in ligand binding. The binding studies, alongside structural definition of diverse N-acetyl monosaccharide binding in the primary S1 pocket and of additional, adjacent binding pockets, able to accommodate both carbohydrate and sulfate functional groups, suggest a versatility in FIBCD1 to recognize chitin oligomers and other pathogen-associated carbohydrate motifs across an extended surface.


Assuntos
Receptores de Superfície Celular , Humanos , Acetatos , Sítios de Ligação/fisiologia , Carboidratos/química , Quitina/metabolismo , Hemostáticos , Ligantes , Ligação Proteica , Receptores de Superfície Celular/química , Receptores de Superfície Celular/metabolismo , Sulfatos , Modelos Moleculares , Estrutura Terciária de Proteína
2.
Stem Cells Dev ; 32(19-20): 606-621, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37551982

RESUMO

The mature brain contains an incredible number and diversity of cells that are produced and maintained by heterogeneous pools of neural stem cells (NSCs). Two distinct types of NSCs exist in the developing and adult mouse brain: Glial Fibrillary Acidic Protein (GFAP)-negative primitive (p)NSCs and downstream GFAP-positive definitive (d)NSCs. To better understand the embryonic functions of NSCs, we performed clonal lineage tracing within neurospheres grown from either pNSCs or dNSCs to enrich for their most immediate downstream neural progenitor cells (NPCs). These clonal progenitor lineage tracing data allowed us to construct a hierarchy of progenitor subtypes downstream of pNSCs and dNSCs that were then validated using single-cell transcriptomics. Further, we identify Nexn as required for neuronal specification from neuron/astrocyte progenitor cells downstream of rare pNSCs. Combined, these data provide single-cell resolution of NPC lineages downstream of rare pNSCs that likely would be missed from population-level analyses in vivo.


Assuntos
Células-Tronco Neurais , Camundongos , Animais , Proteína Glial Fibrilar Ácida/genética , Proteína Glial Fibrilar Ácida/metabolismo , Células-Tronco Neurais/metabolismo , Neurônios/metabolismo , Encéfalo/metabolismo , Astrócitos/metabolismo , Diferenciação Celular/genética
3.
J Sci Med Sport ; 26(9): 476-481, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37574406

RESUMO

OBJECTIVES: Determine the influence of clinically-measured maximum dorsiflexion, dynamic peak dorsiflexion and percent of clinically-measured maximum dorsiflexion used during a drop-jump task on landing biomechanics and risk of ankle injury in military personnel. DESIGN: Prospective cohort study. METHODS: 672 participants (122 women) enrolled. The weightbearing lunge test assessed clinically-measured maximum dorsiflexion averaged across limbs (degrees). Markerless motion capture and force plates collected lower extremity kinematic and kinetic data during a drop-jump task. Percent of clinically-measured maximum dorsiflexion used during landing was calculated as dynamic peak dorsiflexion divided by clinically-measured value, multiplied by 100 (%). De-identified injury data was derived from military physical therapists. Simple linear regression analysis determined the association between dorsiflexion measures and landing biomechanics. Simple binary logistic regression analyses identified predictors of ankle injuries. Statistical significance was set at α = 0.05. RESULTS: Eighteen participants sustained a traumatic ankle injury from a landing. All measures of dorsiflexion were associated with movement patterns that countered the stiff-legged landing strategy with dynamic measures showing a higher predictive value. Protective factors against ankle injury included height (odds ratio: 0.818, p = 0.006) and weight (odds ratio: 0.824, p = 0.023) for women. Relative braking impulse was a risk factor for men (odds ratio: 1.890, p = 0.001). CONCLUSIONS: Greater clinically-measured and dynamic measures of dorsiflexion were associated with movement patterns that countered the stiff-legged landing strategy but neither measure of dorsiflexion predicted ankle injury risk. Resultant biomechanics and anthropometrics influenced ankle injury risk to warrant recognition for injury prevention initiatives.


Assuntos
Traumatismos do Tornozelo , Militares , Masculino , Humanos , Feminino , Tornozelo , Articulação do Joelho , Fenômenos Biomecânicos , Captura de Movimento , Estudos Prospectivos , Articulação do Tornozelo , Amplitude de Movimento Articular
5.
J Adolesc ; 95(2): 296-310, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36345077

RESUMO

INTRODUCTION: Adolescent romantic relationships are developmentally significant, but relatively brief and often disrupted by changes in context. Large individual differences and age-related change make sampling complex. Most adolescents have multiple romantic relationships. Which should we sample? To better understand the issues involved, this study used a simulation - an agent-based computational model - to generate model worlds, each following the relationships formed and dissolved over 5 years. Cross-sectional sample estimates of the number, duration, and type of relationships were compared to population parameters of all relationships formed within the 5 years. Computational models can provide useful insight into sampling bias because (1) the processes producing the results are explicit, (2) results can be replicated to reduce sample idiosyncrasies, and (3) sample statistics can be compared to known population parameters. METHODS: 1000 iterations were run of an agent-based model following 1000 individuals interacting for 60 "months." The model included three types of individuals differing in relationship duration. Two sets of 1000 cross-sectional samples were drawn from the 60,000 cross-sectional "months." Sample statistics were compared to the population parameters. RESULTS: Cross-sectional samples systematically over-represented longer relationships. The ability to detect individual differences in the duration and number of partners varied with time. These results suggest that cross-sectional survey and observational studies may be time sensitive and systematically distort our understanding of adolescent romantic relationships by oversampling longer-term relationships. Results also illustrate how computational models can provide insight into complex phenomena.


Assuntos
Comportamento do Adolescente , Relações Interpessoais , Humanos , Adolescente , Estudos Transversais , Viés de Seleção , Viés
6.
Nat Commun ; 13(1): 7506, 2022 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-36473869

RESUMO

Pediatric medulloblastoma (MB) is the most common solid malignant brain neoplasm, with Group 3 (G3) MB representing the most aggressive subgroup. MYC amplification is an independent poor prognostic factor in G3 MB, however, therapeutic targeting of the MYC pathway remains limited and alternative therapies for G3 MB are urgently needed. Here we show that the RNA-binding protein, Musashi-1 (MSI1) is an essential mediator of G3 MB in both MYC-overexpressing mouse models and patient-derived xenografts. MSI1 inhibition abrogates tumor initiation and significantly prolongs survival in both models. We identify binding targets of MSI1 in normal neural and G3 MB stem cells and then cross referenced these data with unbiased large-scale screens at the transcriptomic, translatomic and proteomic levels to systematically dissect its functional role. Comparative integrative multi-omic analyses of these large datasets reveal cancer-selective MSI1-bound targets sharing multiple MYC associated pathways, providing a valuable resource for context-specific therapeutic targeting of G3 MB.


Assuntos
Neoplasias Encefálicas , Neoplasias Cerebelares , Meduloblastoma , Animais , Camundongos , Humanos , Proteômica , Meduloblastoma/genética , Proteínas de Ligação a RNA/genética , Neoplasias Cerebelares/genética , Proteínas do Tecido Nervoso
7.
Cancer Cell ; 40(12): 1488-1502.e7, 2022 12 12.
Artigo em Inglês | MEDLINE | ID: mdl-36368321

RESUMO

MYC-driven medulloblastoma (MB) is an aggressive pediatric brain tumor characterized by therapy resistance and disease recurrence. Here, we integrated data from unbiased genetic screening and metabolomic profiling to identify multiple cancer-selective metabolic vulnerabilities in MYC-driven MB tumor cells, which are amenable to therapeutic targeting. Among these targets, dihydroorotate dehydrogenase (DHODH), an enzyme that catalyzes de novo pyrimidine biosynthesis, emerged as a favorable candidate for therapeutic targeting. Mechanistically, DHODH inhibition acts on target, leading to uridine metabolite scarcity and hyperlipidemia, accompanied by reduced protein O-GlcNAcylation and c-Myc degradation. Pyrimidine starvation evokes a metabolic stress response that leads to cell-cycle arrest and apoptosis. We further show that an orally available small-molecule DHODH inhibitor demonstrates potent mono-therapeutic efficacy against patient-derived MB xenografts in vivo. The reprogramming of pyrimidine metabolism in MYC-driven medulloblastoma represents an unappreciated therapeutic strategy and a potential new class of treatments with stronger cancer selectivity and fewer neurotoxic sequelae.


Assuntos
Neoplasias Cerebelares , Meduloblastoma , Criança , Humanos , Meduloblastoma/tratamento farmacológico , Meduloblastoma/genética , Meduloblastoma/metabolismo , Di-Hidro-Orotato Desidrogenase , Linhagem Celular Tumoral , Recidiva Local de Neoplasia , Pirimidinas/uso terapêutico , Neoplasias Cerebelares/tratamento farmacológico , Neoplasias Cerebelares/genética , Neoplasias Cerebelares/metabolismo
8.
Eur J Haematol ; 109(2): 166-181, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35531791

RESUMO

BACKGROUND: Effective treatments for hematologic malignancies include therapies that target tyrosine kinase (TK) signaling pathways. Tumor lysis syndrome (TLS) is an oncologic emergency that can occur due to rapid turnover following the initiation of treatments for hematologic malignancy. The incidence of TLS is under-reported and it is unclear as to whether TK inhibitors (TKIs) are associated with TLS. OBJECTIVE: To conduct a systematic review to determine the incidence of TLS with TKIs. METHODS: A search was performed using EMBASE, MEDLINE, and Web of Science electronic databases, as well as a manual search of the American Society of Hematology and American Society of Clinical Oncology abstract databases. Keywords included: "tumor lysis syndrome," "tyrosine kinase inhibitors," "lymphoma," and "leukemia." RESULTS: We identified a total of 57 publications that commented on the incidence of TLS with TKIs for hematologic malignancy. Thirty-nine of those publications reported TLS as an adverse event. TLS was described as an adverse event among essentially all the subclasses of TKIs that are used to manage hematologic malignancies. CONCLUSION: The overall number of articles commenting on TLS as an adverse event is sparse and there needs to be more transparency regarding the incidence of TLS when employing newer targeted therapies. Physicians should consider the risk of TLS on an individual basis and the added risk of TLS when using TKIs to treat hematologic malignancy.


Assuntos
Neoplasias Hematológicas , Síndrome de Lise Tumoral , Neoplasias Hematológicas/complicações , Neoplasias Hematológicas/tratamento farmacológico , Humanos , Inibidores de Proteínas Quinases/efeitos adversos , Proteínas Tirosina Quinases , Fatores de Risco , Síndrome de Lise Tumoral/diagnóstico , Síndrome de Lise Tumoral/tratamento farmacológico , Síndrome de Lise Tumoral/etiologia
9.
Front Oncol ; 12: 815726, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35155252

RESUMO

Pediatric central nervous system (CNS) tumors are the most common solid tumors diagnosed in children and are the leading cause of pediatric cancer-related death. Those who do survive are faced with the long-term adverse effects of the current standard of care treatments of chemotherapy, radiation, and surgery. There is a pressing need for novel therapeutic strategies to treat pediatric CNS tumors more effectively while reducing toxicity - one of these novel modalities is chimeric antigen receptor (CAR) T-cell therapy. Currently approved for use in several hematological malignancies, there are promising pre-clinical and early clinical data that suggest CAR-T cells could transform the treatment of pediatric CNS tumors. There are, however, several challenges that must be overcome to develop safe and effective CAR T-cell therapies for CNS tumors. Herein, we detail these challenges, focusing on those unique to pediatric patients including antigen selection, tumor immunogenicity and toxicity. We also discuss our perspective on future avenues for CAR T-cell therapies and potential combinatorial treatment approaches.

10.
Methods Mol Biol ; 2423: 1-12, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34978683

RESUMO

Medulloblastoma (MB) is the most common malignant pediatric brain tumor, representing 60% of childhood intracranial embryonal tumors. Despite multimodal advances in therapies over the last 20 years that have yielded a 5-year survival rate of 75%, high-risk patients (younger than 3 years, subtotal resection, metastatic lesions at diagnosis) still experience a 5-year overall survival of less than 70%. In this introductory chapter on pediatric MB, we describe the initial discrimination of MB based on histopathological examination and the more recent progress made in global gene expression profiling methods that have allowed scientists to more accurately subclassify and prognosticate on MB based on molecular characteristics. The identification of subtype-specific molecular drivers and pathways presents novel therapeutic targets that could lead to MB subtype-specific treatment modalities. Additionally, we detail how the cancer stem cell (CSC) hypothesis provides an explanation for tumor recurrence, and the potential for CSC-targeted therapies to address treatment-refractory MB. These personalized therapies can potentially increase MB survivorship and negate some of the long-term neurotoxicity associated with the current standard of care for MB patients.


Assuntos
Neoplasias Cerebelares , Meduloblastoma , Neoplasias Cerebelares/diagnóstico , Neoplasias Cerebelares/genética , Neoplasias Cerebelares/terapia , Criança , Perfilação da Expressão Gênica , Humanos , Meduloblastoma/diagnóstico , Meduloblastoma/genética , Meduloblastoma/terapia , Recidiva Local de Neoplasia/patologia , Células-Tronco Neoplásicas/metabolismo
11.
Sci Adv ; 7(50): eabi5568, 2021 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-34878832

RESUMO

Medulloblastoma (MB) remains a leading cause of cancer-related mortality among children. The paucity of MB samples collected at relapse has hindered the functional understanding of molecular mechanisms driving therapy failure. New models capable of accurately recapitulating tumor progression in response to conventional therapeutic interventions are urgently needed. In this study, we developed a therapy-adapted PDX MB model that has a distinct advantage of generating human MB recurrence. The comparative gene expression analysis of MB cells collected throughout therapy led to identification of genes specifically up-regulated after therapy, including one previously undescribed in the setting of brain tumors, bactericidal/permeability-increasing fold-containing family B member 4 (BPIFB4). Subsequent functional validation resulted in a markedly diminished in vitro proliferation, self-renewal, and longevity of MB cells, translating into extended survival and reduced tumor burden in vivo. Targeting endothelial nitric oxide synthase, a downstream substrate of BPIFB4, impeded growth of several patient-derived MB lines at low nanomolar concentrations.

12.
J Biol Chem ; 294(45): 17155-17165, 2019 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-31562242

RESUMO

Bovine conglutinin is an immune protein that is involved in host resistance to microbes and parasites and interacts with complement component iC3b, agglutinates erythrocytes, and neutralizes influenza A virus. Here, we determined the high-resolution (0.97-1.46 Å) crystal structures with and without bound ligand of a recombinant fragment of conglutinin's C-terminal carbohydrate-recognition domain (CRD). The structures disclosed that the high-affinity ligand N-acetyl-d-glucosamine (GlcNAc) binds in the collectin CRD calcium site by interacting with the O3' and O4' hydroxyls alongside additional specific interactions of the N-acetyl group oxygen and nitrogen with Lys-343 and Asp-320, respectively. These residues, unique to conglutinin and differing both in sequence and in location from those in other collectins, result in specific, high-affinity binding for GlcNAc. The binding pocket flanking residue Val-339, unlike the equivalent Arg-343 in the homologous human surfactant protein D, is sufficiently small to allow conglutinin Lys-343 access to the bound ligand, whereas Asp-320 lies in an extended loop proximal to the ligand-binding site and bounded at both ends by conserved residues that coordinate to both calcium and ligand. This loop becomes ordered on ligand binding. The electron density revealed both α and ß anomers of GlcNAc, consistent with the added α/ßGlcNAc mixture. Crystals soaked with α1-2 mannobiose, a putative component of iC3b, reported to bind to conglutinin, failed to reveal bound ligand, suggesting a requirement for presentation of mannobiose as part of an extended physiological ligand. These results reveal a highly specific GlcNAc-binding pocket in conglutinin and a novel collectin mode of carbohydrate recognition.


Assuntos
Acetilglucosamina/metabolismo , Colectinas/química , Colectinas/metabolismo , Soroglobulinas/química , Soroglobulinas/metabolismo , Sequência de Aminoácidos , Animais , Sítios de Ligação , Bovinos , Cristalografia por Raios X , Ligantes , Modelos Moleculares , Ligação Proteica , Conformação Proteica
13.
PLoS One ; 13(6): e0199175, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29912941

RESUMO

The crystal structures of a biologically and therapeutically active recombinant homotrimeric fragment of native human SP-D (hSP-D) complexed with the inner core oligosaccharide of the Salmonella enterica sv Minnesota rough strains R5 and R7 (rough mutant chemotypes Rc and Rd1) have been determined. The structures reveal that hSP-D specifically and preferentially targets the LPS inner core via the innermost conserved Hep-Kdo pair with the flexibility for alternative recognition when this preferred epitope is not available for binding. Hep-Kdo binding is achieved through calcium dependent recognition of the heptose dihydroxyethyl side chain coupled with specific interactions between the Kdo and the binding site flanking residues Arg343 and Asp325 with evidence for an extended binding site for LPS inner cores containing multiple Kdo residues. In one subunit of the R5-bound structure this preferred mode of binding is precluded by the crystal lattice and oligosaccharide is bound through the terminal inner core glucose. The structures presented here thus provide unique multiple insights into the recognition and binding of bacterial LPS by hSP-D. Not only is it demonstrated that hSP-D targets the highly conserved LPS proximal inner core Hep-Kdo motif, but also that hSP-D can recognise either terminal or non-terminal sugars and has the flexibility and versatility to adopt alternative strategies for bacterial recognition, utilising alternative LPS epitopes when the preferred inner core Hep-Kdo disaccharide is not available for binding.


Assuntos
Lipopolissacarídeos/metabolismo , Proteína D Associada a Surfactante Pulmonar/metabolismo , Salmonella enterica/metabolismo , Sítios de Ligação , Epitopos/química , Lipopolissacarídeos/química , Estrutura Molecular , Oligossacarídeos/química , Oligossacarídeos/metabolismo , Proteína D Associada a Surfactante Pulmonar/química , Proteína D Associada a Surfactante Pulmonar/isolamento & purificação , Proteínas Recombinantes
14.
J Biol Chem ; 289(5): 2880-7, 2014 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-24293368

RESUMO

The high resolution crystal structures of a recombinant fragment of the C-terminal fibrinogen-like recognition domain of FIBCD1, a vertebrate receptor that binds chitin, have been determined. The overall tetrameric structure shows similarity in structure and aggregation to the horseshoe crab innate immune protein tachylectin 5A. The high affinity ligand N-acetylmannosamine (ManNAc) binds in the S1 site, predominantly via the acetyl group with the oxygen and acetamide nitrogen hydrogen-bonded to the protein and the methyl group inserted into a hydrophobic pocket. The binding of the ManNAc pyranose ring differs markedly between the two independent subunits, but in all structures the binding of the N-acetyl group is conserved. In the native structure, a crystal contact results in one of the independent protomers binding the first GlcNAc of the Asn(340) N-linked glycan on the other independent protomer. In the ligand-bound structure this GlcNAc is replaced by the higher affinity ligand ManNAc. In addition, a sulfate ion has been modeled into the electron density at a location similar to the S3 binding site in L-ficolin, whereas in the native structure an acetate ion has been placed in the S1 N-acetyl binding site, and a sulfate ion has been placed adjacent to this site. These ion binding sites are ideally placed to receive the N-acetyl and sulfate groups of sulfated GalNAc residues of glycosaminoglycans such as chondroitin and dermatan sulfate. Together, these structures give insight into important determinants of ligand selectivity, demonstrating versatility in recognition and binding while maintaining conservation in N-acetyl and calcium binding.


Assuntos
Quitina/metabolismo , Receptores de Superfície Celular/química , Receptores de Superfície Celular/metabolismo , Acetilação , Sequência de Aminoácidos , Animais , Sítios de Ligação , Cálcio/metabolismo , Linhagem Celular , Quitina/química , Cristalografia por Raios X , Fibrinogênio/química , Humanos , Insetos/citologia , Ligantes , Dados de Sequência Molecular , Estrutura Quaternária de Proteína , Estrutura Terciária de Proteína , Receptores de Superfície Celular/genética , Relação Estrutura-Atividade
15.
J Sci Food Agric ; 91(12): 2217-33, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21547920

RESUMO

BACKGROUND: The causes of the natural variation in nitrate accumulation and associated traits are studied using a diverse population of 48 mature lettuce accessions grown hydroponically in winter and summer seasons. Information on the effects of genotype, environment and their interactions will inform future selection strategies for the production of low-nitrate varieties more suited to meeting EU requirements for harvested produce. RESULTS: The effects of genotype (G), environment (E) and G × E interactions were all significant, with nitrate concentrations lower but covering a wider range in summer. Concentrations of nitrate-N were positively correlated with those of water and total-N and negatively with assimilated-C in the shoot in both seasons, with all relationships partitioned according to morphotype and/or seasonal type. Corresponding relationships between nitrate-N and assimilated-N or with shoot fresh or dry weight were generally weak or inconsistent. Nitrate concentrations at an early growth stage were strongly related to those at maturity in winter, but not in summer when light levels were less variable. CONCLUSION: The effects of genotype and environment on nitrate accumulation in lettuce are strongly influenced by morphotype, with most G × E interactions between accessions within the same morphotype predominantly of the non-crossover type. All low-nitrate-accumulating genotypes have increased concentrations of organic solutes (concentration regulation) and reduced water (volume regulation) to help stabilise osmotic potential within the shoots. Variability in nitrate accumulation arises more from differences in uptake than in efficiency of its chemical reduction. Genotypic differences in nitrate accumulation can be masked by changes in head morphology during maturation, provided that they are not confounded by substantial changes in intercepted light. Recent selection strategies do not appear to have produced lower-nitrate-accumulating cultivars.


Assuntos
Interação Gene-Ambiente , Variação Genética , Lactuca/genética , Lactuca/metabolismo , Nitratos/metabolismo , Brotos de Planta/crescimento & desenvolvimento , Transporte Biológico , Ciclo do Carbono/efeitos da radiação , Cruzamentos Genéticos , União Europeia , Contaminação de Alimentos/legislação & jurisprudência , Contaminação de Alimentos/prevenção & controle , Genótipo , Hidroponia , Lactuca/crescimento & desenvolvimento , Lactuca/efeitos da radiação , Ciclo do Nitrogênio/efeitos da radiação , Pressão Osmótica , Brotos de Planta/metabolismo , Brotos de Planta/efeitos da radiação , Reprodutibilidade dos Testes , Estações do Ano , Luz Solar , Fatores de Tempo , Reino Unido , Água/análise
16.
J Sci Food Agric ; 91(3): 553-62, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21218492

RESUMO

BACKGROUND: Nitrate accumulates in plants in response to N supply, aerial environment (predominantly light), and genotype. This paper characterises the effects of genotype, environment, and their interactions on nitrate accumulation by 24 cultivated and wild lettuce accessions grown hydroponically in winter and summer. The results will inform future strategies for selecting for low-nitrate varieties. RESULTS: A preliminary study in which two accessions were sampled for nitrate over time showed largest differences between cultivars in the early-middle period of growth. Sampling the whole population of lettuce at this stage revealed significant effects of genotype, environment (with nitrate concentrations generally higher in winter), and genotype × environment interactions (largely due to a wider range of concentrations in summer). Changes in the ranking of accessions for nitrate accumulation between the two growing seasons were generally small for cultivated morphotypes. Shoot nitrate concentrations and water contents were positively associated, particularly in summer when separate relationships for different cultivated morphotypes (butterhead, cos/Romaine, crisp, leaf, and stem lettuce) were detected. Expressing nitrate concentration on either a shoot fresh or dry matter basis had relatively little effect on the ranking of most cultivated accessions, but not for the wild types. CONCLUSION: There is a well-defined sampling window when differences in nitrate accumulation between lettuce genotypes are at a maximum. Delaying sampling may allow morphological changes in head form to mask earlier genotypic differences. Genotype × environment interactions are predominantly of the non-crossover type and have only a small effect on changes in the ranking of accessions between seasons, allowing selections to be made at any time of year. At least part of the genotypic variation in nitrate accumulation is associated with differences in shoot water content.


Assuntos
Meio Ambiente , Genótipo , Lactuca/genética , Lactuca/metabolismo , Nitratos/metabolismo , Dessecação , Fenótipo , Brotos de Planta , Estações do Ano , Especificidade da Espécie , Água/análise
17.
J Mol Biol ; 386(5): 1240-54, 2009 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-19452596

RESUMO

The serum-amyloid-P-component-like pentraxin from Limulus polyphemus, a recently discovered pentraxin species and important effector protein of the hemolymph immune system, displays two distinct doubly stacked cyclic molecular aggregations, heptameric and octameric. The refined three-dimensional structures determined by X-ray crystallography, both based on the same cDNA sequence, show that each aggregate is constructed from a similar dimer of protomers, which is repeated to make up the ring structure. The native octameric form has been refined at a resolution of 3 A, the native heptameric form at 2.3 A, and the phosphoethanolamine (PE)-bound octameric form at 2.7 A. The existence of the hitherto undescribed heptameric form was confirmed by single-particle analysis using cryo-electron microscopy. In the native structures, the calcium-binding site is similar to that in human pentraxins, with two calcium ions bound in each subunit. Upon binding PE, however, each subunit binds a third calcium ion, with all three calcium ions contributing to the binding and orientation of the bound phosphate group within the ligand-binding pocket. While the phosphate is well-defined in the electron density, the ethanolamine group is poorly defined, suggesting structural and binding variabilities of this group. Although sequence homology with human serum amyloid P component is relatively low, structural homology is high, with very similar overall folds and a common affinity for PE. This is due, in part, to a "topological" equivalence of side-chain position. Identical side chains that are important in both function and fold, from different regions of the sequence in human and Limulus structures, occupy similar space within the overall subunit fold. Sequence and structure alignment, based on the refined three-dimensional structures presented here and the known horseshoe crab pentraxin sequences, suggest that adaptation and refinement of C-reactive-protein-mediated immune responses in these ancient creatures lacking antibody-based immunity are based on adaptation by gene duplication.


Assuntos
Caranguejos Ferradura/metabolismo , Modelos Moleculares , Componente Amiloide P Sérico/química , Animais , Sítios de Ligação , Cálcio/metabolismo , Microscopia Crioeletrônica , Cristalografia por Raios X , Humanos , Ligantes , Microscopia Eletrônica de Transmissão , Regiões Promotoras Genéticas , Ligação Proteica , Conformação Proteica , Multimerização Proteica , Componente Amiloide P Sérico/metabolismo
18.
Dev Comp Immunol ; 32(11): 1281-9, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18538390

RESUMO

The potential of C-reactive protein (CRP)-like proteins to be used as a biomarker of health status in cultured carp obtained from various European fish lines has been assessed. Varying CRP-like protein levels in the serum of carp were monitored using an indirect competitive enzyme-linked immunosorbent assay. CRP-like protein basal levels in normal fish varied between carp lines, ranging on average from 2.9+/-0.15 to 12.57+/-1.19 microg ml(-1). Serum levels of CRP-like protein in carp were observed to increase several fold in fish infected with the pathogen Aeromonas hydrophila. However, carp injected with Escherichia coli lipopolysaccharide (LPS) serotype 0111:B4 did not exhibit an increase in CRP-like proteins levels.


Assuntos
Aeromonas hydrophila , Proteína C-Reativa/metabolismo , Carpas/sangue , Escherichia coli , Lipopolissacarídeos/farmacologia , Sequência de Aminoácidos , Animais , Proteína C-Reativa/química , Proteína C-Reativa/isolamento & purificação , Dados de Sequência Molecular , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos
19.
Ann Bot ; 99(1): 171-82, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17210608

RESUMO

BACKGROUND AND AIMS: Growth of bedding plants, in small peat plugs, relies on nutrients in the irrigation solution. The object of the study was to find a way of modifying the nutrient supply so that good-quality seedlings can be grown rapidly and yet have the high root : shoot ratios essential for efficient transplanting. METHODS: A new procedure was devised in which the concentrations of nutrients in the irrigation solution were modified during growth according to changing plant demand, instead of maintaining the same concentrations throughout growth. The new procedure depends on published algorithms for the dependence of growth rate and optimal plant nutrient concentrations on shoot dry weight W(s) (g m(-2)), and on measuring evapotranspiration rates and shoot dry weights at weekly intervals. Pansy, Viola tricola 'Universal plus yellow' and petunia, Petunia hybrida 'Multiflora light salmon vein' were grown in four independent experiments with the expected optimum nutrient concentration and fractions of the optimum. Root and shoot weights were measured during growth. KEY RESULTS: For each level of nutrient supply W(s) increased with time (t) in days, according to the equation DeltaW(s)/Deltat=K(2)W(s)/(100+W(s)) in which the growth rate coefficient (K(2)) remained approximately constant throughout growth. The value of K(2) for the optimum treatment was defined by incoming radiation and temperature. The value of K(2) for each sub-optimum treatment relative to that for the optimum treatment was logarithmically related to the sub-optimal nutrient supply. Provided the aerial environment was optimal, R(sb)/R(o) approximately W(o)/W(sb) where R is the root : shoot ratio, W is the shoot dry weight, and sb and o indicate sub-optimum and optimum nutrient supplies, respectively. Sub-optimal nutrient concentrations also depressed shoot growth without appreciably affecting root growth when the aerial environment was non-limiting. CONCLUSION: The new procedure can predict the effects of nutrient supply, incoming radiation and temperature on the time course of shoot growth and the root : shoot ratio for a range of growing conditions.


Assuntos
Jardinagem/métodos , Petunia/crescimento & desenvolvimento , Raízes de Plantas/crescimento & desenvolvimento , Brotos de Planta/crescimento & desenvolvimento , Viola/crescimento & desenvolvimento , Meio Ambiente , Fertilizantes , Modelos Biológicos
20.
J Gerontol Nurs ; 30(2): 37-45, 2004 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15022825

RESUMO

Multisensory environments such as Snoezelen rooms are becoming increasingly popular in health care facilities for older individuals. There is limited reliable evidence of the benefits of such innovations, and the effect they have on residents, caregivers, and visitors in these facilities. This two-stage project examined how effective two types of multisensory environments were in improving the well-being of older individuals with dementia. The two multisensory environments were a Snoezelen room and a landscaped garden. These environments were compared to the experience of the normal living environment. The observed response of 24 residents with dementia in a nursing home was measured during time spent in the Snoezelen room, in the garden, and in the living room. In the second part of the project, face-to-face interviews were conducted with six caregivers and six visitors to obtain their responses to the multisensory environments. These interviews identified the components of the environments most used and enjoyed by residents and the ways in which they could be improved to maximize well-being.


Assuntos
Demência/psicologia , Planejamento Ambiental/normas , Promoção da Saúde/organização & administração , Instituição de Longa Permanência para Idosos/normas , Atividades de Lazer/psicologia , Casas de Saúde/normas , Sensação , Afeto , Idoso/psicologia , Atitude do Pessoal de Saúde , Atitude Frente a Saúde , Demência/enfermagem , Avaliação Geriátrica , Enfermagem Geriátrica/métodos , Ambiente de Instituições de Saúde/normas , Humanos , Decoração de Interiores e Mobiliário/normas , Pesquisa Metodológica em Enfermagem , Recursos Humanos de Enfermagem/psicologia , Pesquisa Qualitativa , Inquéritos e Questionários , Vitória , Visitas a Pacientes/psicologia
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