RESUMO
Neuropeptides have diverse roles in the function and development of the nervous system. With the completion of the sequencing of the C. elegans genome, rapid identification of nematode neuropeptide genes is possible. To date, 41 C. elegans neuropeptide genes have been identified. Of these genes, 20 genes, named flp (FMRFamide-like peptide) genes, encode FMRFamide-related proteins (FaRPs). Deletion of one of the flp genes, flp-1, results in several behavioral defects, suggesting that at least one flp gene is not functionally redundant with other flp genes. Twenty-one genes, named neuropeptide-like protein (nlp) genes, encode peptides distinct from the FaRP family. The predicted nlp-1 and nlp-2 neuropeptides have modest similarity to buccalin and myomodulin, respectively. Cellular expression patterns and genetic analysis of flp and nlp genes suggest that neuropeptides in nematodes also have widespread and varied roles in nervous system function.
Assuntos
Caenorhabditis elegans/genética , Genes de Helmintos , Família Multigênica , Neuropeptídeos/genética , Sequência de Aminoácidos , Animais , Caenorhabditis elegans/fisiologia , FMRFamida/análogos & derivados , FMRFamida/química , FMRFamida/genética , Dados de Sequência Molecular , Neuropeptídeos/química , Alinhamento de Sequência , Homologia de Sequência de AminoácidosRESUMO
Placental malaria infection jeopardizes pregnancy outcome, and its influence may also impair the transplacental transfer of some antibodies. Two hundred and thirteen Gambian mother-baby pairs were studied to determine the influence of placental malaria infection and maternal hypergammaglobulinaemia on transplacental transfer of measles and tetanus antibodies in Gambian population. Placental blood and tissue were collected for placental malaria diagnosis. Cord and maternal sera were tested for total IgG concentration by laser nephelometry and for IgG antibody to tetanus toxoid and measles by ELISA. The prevalence of placental malaria infection was 51.1%. Mothers whose placentae were parasitized had a significantly higher mean total serum IgG (22.0 g/L vs 11.3 g/L, p < 0.001) and measles antibody level (4.02 IU/mL vs 1.21 IU/mL, p < 0.01), but not tetanus antibody, than mothers with non-parasitized placentae. Results of multiple regression analysis showed that placental malaria infection and maternal hypergammaglobulinaemia were associated with the reduction of 72% (95% CI 67.84) and 86% (95% CI 76.91) in transplacental transfer of measles antibody respectively but did not influence the transfer of tetanus antibody. It is concluded that the combined influence of placental malaria infection and maternal hypergammaglobulinaemia is significantly associated with the transfer of impaired measles antibody in this population.
Assuntos
Hipergamaglobulinemia/imunologia , Imunidade Materno-Adquirida , Malária/imunologia , Placenta/imunologia , Complicações na Gravidez/imunologia , Adulto , Anticorpos/metabolismo , Clostridium tetani/imunologia , Feminino , Sangue Fetal/imunologia , Humanos , Imunoglobulina G/sangue , Transmissão Vertical de Doenças Infecciosas , Troca Materno-Fetal , Sarampo/imunologia , Vírus do Sarampo/imunologia , Placenta/parasitologia , Gravidez , Complicações na Gravidez/parasitologia , Saúde da População Rural , Tétano/imunologia , Toxoide Tetânico/imunologiaRESUMO
One of the most promising materials for fabricating cold cathodes for next generation high-performance flat panel devices is carbon nanotubes (CNTs). For this purpose, CNTs grown on metallic substrates are used to minimize contact resistance. In this report, we compare properties and field emission performance of CNTs grown via water assisted chemical vapor deposition using Inconel vs silicon (Si) substrates. Carbon nanotube forests grown on Inconel substrates are superior to the ones grown on silicon; low turn-on fields (â¼1.5 V/µm), high current operation (â¼100 mA/cm(2)) and very high local field amplification factors (up to â¼7300) were demonstrated, and these parameters are most beneficial for use in vacuum microelectronic applications.
RESUMO
In most animals, multiple genes encode protein kinase C (PKC) proteins. Pharmacological studies have revealed numerous roles for this protein family, yet the in vivo roles of specific PKC proteins and the functional targets of PKC activation are poorly understood. We find that in Caenorhabditis elegans, two PKC genes, pkc-1 and tpa-1, are required for mechanosensory response; the role of the nPKCε/η ortholog, pkc-1, was examined in detail. pkc-1 function is required for response to nose touch in adult C. elegans and pkc-1 likely acts in the interneurons that regulate locomotion which are direct synaptic targets of mechanosensory neurons. Previous studies have suggested numerous possible targets of pkc-1; our analysis indicates that pkc-1 may act via the extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) pathway. We find that ERK/MAPK pathway function is required for mechanosensory response in C. elegans and that at least one component of this pathway, lin-45 Raf, acts in interneurons of the mechanosensory circuit. Genetic analysis indicates that lin-45 and pkc-1 act together to regulate nose touch response. Thus, these results functionally link two conserved signaling pathways in adult C. elegans neurons and define distinct roles for PKC genes in vivo.
Assuntos
Proteínas de Caenorhabditis elegans/fisiologia , Caenorhabditis elegans/enzimologia , MAP Quinases Reguladas por Sinal Extracelular/fisiologia , Sistema de Sinalização das MAP Quinases , Mecanorreceptores/enzimologia , Quinases raf/metabolismo , Animais , Caenorhabditis elegans/fisiologia , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/genética , Sistema de Sinalização das MAP Quinases/genética , Mecanorreceptores/fisiologia , Proteína Quinase C/fisiologia , Proteína Quinase C-épsilon/fisiologia , Quinases raf/genética , Quinases raf/fisiologiaRESUMO
Easy-to-fabricate, low-loss optical fibers are described that consist of a pure fused silica core surrounded with a loosely fitting, extruded, FEP cladding tube. Because of their large numerical aperture (NA), these fibers are particularly well suited for the transmission of the incoherent light emitted by light-emitting diodes. Whereas the losses approached those of the core material for small angle excitation (i.e., 7.6 dB/km at 0.8 microm for a Suprasil 2 fiber of 230-m length), they increased to 14 dB/km for a steady-state NA of 0.3. The measured pulse dispersion of up to 30 nsec agrees well with the expected 24 nsec for a stepindex fiber with an NA of 0.3.
RESUMO
The fate of the R7 photoreceptor cell in the Drosophila compound eye is established by a specific inductive interaction between the R8 photoreceptor neuron and the R7 precursor cell. This induction is mediated by two cell-surface proteins: the ligand, bride of sevenless (boss), and sevenless (sev), a tyrosine-kinase receptor. The structure of boss is unique for a ligand of a tyrosine-kinase receptor. It contains a large extracellular domain, seven transmembrane segments, and a carboxy-terminal cytoplasmic tail. Here we report that: (1) boss activates tyrosine phosphorylation of the sev receptor; (2) the seven transmembrane domain of boss is necessary for its function; and (3) a soluble form of boss acts as an antagonist of the sev receptor both in vivo and in vitro.
Assuntos
Proteínas de Bactérias , Proteínas de Drosophila , Drosophila/fisiologia , Proteínas do Olho/fisiologia , Glicoproteínas de Membrana/fisiologia , Células Fotorreceptoras/fisiologia , Proteínas Serina-Treonina Quinases/genética , Proteínas Tirosina Quinases/metabolismo , Receptores Proteína Tirosina Quinases , Receptores de Superfície Celular/fisiologia , Receptores de Peptídeos , Animais , Anticorpos Monoclonais , Linhagem Celular , Drosophila/genética , Proteínas do Olho/antagonistas & inibidores , Proteínas do Olho/genética , Expressão Gênica , Cinética , Ligantes , Glicoproteínas de Membrana/antagonistas & inibidores , Glicoproteínas de Membrana/genética , Neurônios/fisiologia , Fosfotirosina , Receptores de Superfície Celular/genética , Transfecção , Tirosina/análogos & derivados , Tirosina/análiseRESUMO
The influence of prematurity and low birth weight (LBW) on transplacental transfer of Haemophilus influenza type B and Streptococcus pneumoniae antibodies was assessed in 213 mothers and their neonates from Gambia. Paired maternal and cord serum samples were tested for specific IgG antibody titres for H. influenza and S. pneumococcus antigens using enzyme linked immunosorbent assay. Prematurity and LBW was significantly associated with reduced placental antibody transfer for these antigens.The reduced materno-foetal transfer of these antibodies in this vulnerable population of babies may further predispose them to more bacterial infections. These findings are of practical importance to the vaccination strategies.
Assuntos
Anticorpos Antibacterianos/sangue , Haemophilus influenzae/imunologia , Imunidade Materno-Adquirida , Streptococcus pneumoniae/imunologia , Cápsulas Bacterianas , Ensaios Clínicos como Assunto , Feminino , Sangue Fetal/imunologia , Gâmbia , Vacinas Anti-Haemophilus/administração & dosagem , Humanos , Imunoglobulina G/sangue , Recém-Nascido de Baixo Peso/imunologia , Recém-Nascido , Recém-Nascido Prematuro/imunologia , Vacinas Pneumocócicas/administração & dosagem , Polissacarídeos Bacterianos/administração & dosagem , Gravidez , Vacinas Conjugadas/administração & dosagemRESUMO
We describe a genetic model for neurodegeneration in the nematode Caenorhabditis elegans. Constitutive activation of the GTP-binding protein Galphas induces neurodegeneration. Neuron loss occurs in two phases whereby affected cells undergo a swelling response in young larvae and subsequently die sometime during larval development. Different neural cell types vary greatly in their susceptibility to Galphas-induced cytotoxicity, ranging from 0 to 88% of cells affected. Mutations that prevent programmed cell death do not prevent Galphas-induced killing, suggesting that these deaths do not occur by apoptosis. Mutations in three genes protect against Galphas-induced cell deaths. The acy-1 gene is absolutely required for neurodegeneration, and the predicted ACY-1 protein is highly similar (40% identical) to mammalian adenylyl cyclases. Thus, Gs-induced neurodegeneration is mediated by the second messenger cAMP. Mutations in the unc-36 and eat-4 genes are partially neuroprotective, which indicates that endogenous signaling modulates the severity of the neurotoxic effects of Galphas. These experiments define an intracellular signaling cascade that triggers a necrotic form of neurodegeneration.
Assuntos
Adenilil Ciclases/genética , Proteínas de Caenorhabditis elegans , Caenorhabditis elegans/genética , Subunidades alfa Gs de Proteínas de Ligação ao GTP/genética , Degeneração Neural/fisiopatologia , Transdução de Sinais/genética , Adenilil Ciclases/metabolismo , Sequência de Aminoácidos , Animais , Apoptose/fisiologia , Comportamento Animal/fisiologia , Caenorhabditis elegans/citologia , Caenorhabditis elegans/enzimologia , AMP Cíclico/metabolismo , Reação de Fuga/fisiologia , Subunidades alfa Gs de Proteínas de Ligação ao GTP/metabolismo , Dados de Sequência Molecular , Mutação/fisiologia , Necrose , Neurônios Aferentes/patologia , Neurônios Aferentes/fisiologiaRESUMO
How does the nervous system encode environmental stimuli as sensory experiences? Both the type (visual, olfactory, gustatory, mechanical or auditory) and the quality of a stimulus (spatial position, intensity or frequency) are represented as a neural code. Here we undertake a genetic analysis of sensory modality coding in Caenorhabditis elegans. The ASH sensory neurons respond to two distinct sensory stimuli (nose touch and osmotic stimuli). A mutation in the glr-1 (glutamate receptor) gene eliminates the response to nose touch but not to osmotic repellents. The predicted GLR-1 protein is roughly 40% identical to mammalian AMPA-class glutamate receptor (GluR) subunits. Analysis of glr-1 expression and genetic mosaics indicates that GLR-1 receptors act in synaptic targets of the ASH neurons. We propose that discrimination between the ASH sensory modalities arises from differential release of ASH neurotransmitters in response to different stimuli.
Assuntos
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans/fisiologia , Proteínas de Membrana/fisiologia , Proteínas do Tecido Nervoso/fisiologia , Neurônios Aferentes/fisiologia , Receptores de Glutamato/fisiologia , Sinapses/fisiologia , Animais , Caenorhabditis elegans/genética , Quimera , Expressão Gênica , Movimento , Mutação , Neurônios/fisiologia , Receptores de AMPA , Receptores de Glutamato/genética , TatoRESUMO
A semiautomated fluorescent immunoassay system (FIAX) for detecting anti-nuclear antibodies (ANAs) in human serum was compared with conventional indirect immunofluorescence using microscope slides (Meloy Laboratories) coated with mouse fibroblasts. The FIAX system uses quantitative indirect immunofluorescence to measure the specific binding of ANA to a sampler coated with human epithelial cells. A total of 101 serum samples were examined for the presence of ANAs by employing both methods. At an initial 1:10 screening dilution, 23 samples were negative for ANAs by the slide method, whereas 21 samples were negative with the FIAX system. Using 2+, 3+, and 4+ subjective brightness, 68 (100%) samples were positive by the slide method, whereas 67 (98.5%) were positive with the FIAX system. ANA-positive samples were diluted twofold from 1:10 to 1:640, and positive titers were determined by both methods. Sixty (77%) of 78 positive samples titrated by FIAX came within +/-1 dilution of the titers determined by the slide method, and 75 (96%) of the samples fell within +/-2 dilutions. Results indicate good correlation between the FIAX system and indirect immunofluorescence for the detection of ANAs in human serum. The FIAX system has the advantage of speed, reproducibility, and the elimination of subjective microscopic assessment of ANA titers.
Assuntos
Anticorpos Antinucleares/análise , Imunofluorescência , Animais , Linhagem Celular , Computadores , Epitélio , Fibroblastos , Congelamento , Temperatura Alta , Humanos , CamundongosRESUMO
Previous genetic mosaic studies established that expression of the Drosophila bride of sevenless (boss) gene is required in photoreceptor neuron R8 for the development of photoreceptor neuron R7. This led to the proposal that boss encodes or regulates an R7-specific inductive cue. We have identified the boss gene based on small deletions in mutant alleles and sequenced both cDNAs and corresponding genomic regions. One P element and three X-ray-induced boss alleles show different deletions in the gene ranging in size from 2 to 23 bp, each causing frameshifts leading to premature termination of translation. The boss gene encodes a protein of 896 amino acids with a putative amino-terminal signal sequence, a large extracellular region of 498 amino acids, and seven potential transmembrane domains followed by a carboxy-terminal cytoplasmic tail of 115 amino acids. The putative membrane localization of the boss protein is consistent with a model in which direct interaction between the boss and sevenless proteins specifies R7 cell fate. Another model in which the boss protein functions as a receptor is proposed based on its similarity to the G protein-linked family of membrane receptors.
Assuntos
Proteínas de Drosophila , Drosophila/genética , Proteínas do Olho/genética , Genes , Glicoproteínas de Membrana , Proteínas de Membrana/genética , Receptores Proteína Tirosina Quinases , Retina/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Southern Blotting , Membrana Celular/metabolismo , DNA/genética , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Conformação Proteica , Células Ganglionares da Retina/metabolismo , Software , Transcrição GênicaRESUMO
During Drosophila retinal development, the R8 photo-receptor neuron induces a neighboring cell to assume an R7 cell fate through cell contact. This is mediated by the transmembrane protein bride of sevenless (boss) on the surface of the R8 cell, which binds the sevenless tyrosine kinase receptor (sev) on the surface of the R7 precursor cell. The boss protein, which contains a large extracellular domain, seven transmembrane segments, and a C-terminal cytoplasmic domain, has an exceptional structure for a ligand of a receptor tyrosine kinase. Using a panel of antibodies directed to various cytoplasmic and extracellular epitopes, we demonstrate that the entire boss protein from its extreme N-terminus to its extreme C-terminus is internalized by sev-expressing tissue culture cells and by the R7 precursor cell in the developing eye imaginal disc. The receptor-mediated transfer of a transmembrane ligand represents a novel mechanism for protein transfer between developing cells.
Assuntos
Proteínas de Drosophila , Drosophila melanogaster/fisiologia , Proteínas do Olho/metabolismo , Glicoproteínas de Membrana/metabolismo , Proteínas de Membrana/metabolismo , Proteínas Tirosina Quinases/metabolismo , Receptores Proteína Tirosina Quinases , Receptores de Superfície Celular/fisiologia , Receptores de Peptídeos , Retina/embriologia , Animais , Endocitose , Proteínas do Olho/química , Proteínas do Olho/imunologia , Ligantes , Glicoproteínas de Membrana/química , Glicoproteínas de Membrana/imunologia , Proteínas de Membrana/química , Proteínas de Membrana/imunologia , Microscopia Eletrônica , Mapeamento de Peptídeos , Ligação ProteicaRESUMO
Neuropeptides play critical roles in synaptic signaling in all nervous systems. Unlike classical neurotransmitters, peptidergic neurotransmitters are encoded as preproproteins that are posttranslationally processed to yield bioactive neuropeptides. To identify novel peptidergic neurotransmitters, the Caenorhabditis elegans genome was searched for predicted proteins with the structural hallmarks of neuropeptide preproproteins. Thirty-two C. elegans neuropeptide-like protein (nlp) genes were identified. The nlp genes define at least 11 families of putative neuropeptides with unique motifs; similar expressed sequence tags were identified in other invertebrate species for all 11 families. Six of these families are defined by putative bioactive motifs (FAFA, GGxYamide, MRxamide, LQFamide, LxDxamide, and GGARAF); the remaining five families are related to allatostatin, myomodulin, buccalin/drosulfakinin, orcokinin, and APGWamide neuropeptides (MGL/Famide, FRPamide, MSFamide, GFxGF, and YGGWamide families, respectively). Most C. elegans nlp gene expression is in neurons. The C. elegans nlp genes and similar genes encoding putative neuropeptides in other species are likely to play diverse roles in nervous system function.
Assuntos
Proteínas de Caenorhabditis elegans/genética , Genes de Helmintos , Neuropeptídeos/genética , Animais , Animais Geneticamente Modificados , Caenorhabditis elegans/genética , Sequência Conservada , Expressão Gênica , Neurônios/metabolismoRESUMO
The Caenorhabditis elegans ASH sensory neurons mediate responses to nose touch, hyperosmolarity, and volatile repellent chemicals. We show here that distinct signaling pathways mediate the responses to touch and hyperosmolarity. ASH neurons distinguish between these stimuli because habituation to nose touch has no effect on the response to high osmolarity or volatile chemicals (1-octanol). Mutations in osm-10 eliminate the response to hyperosmolarity but have no effect on responses to nose touch or to volatile repellents. OSM-10 is a novel cytosolic protein expressed in ASH and three other classes of sensory neurons. Mutations in two other osmosensory-defective genes, eos-1 and eos-2, interact genetically with osm-10. Our analysis suggests that nose touch sensitivity and osmosensation occur via distinct signaling pathways in ASH and that OSM-10 is required for osmosensory signaling.
Assuntos
Proteínas de Caenorhabditis elegans , Neurônios Aferentes/fisiologia , Sensação/fisiologia , Transdução de Sinais/fisiologia , Tato/fisiologia , Equilíbrio Hidroeletrolítico/fisiologia , Sequência de Aminoácidos/genética , Animais , Caenorhabditis elegans , Mecanorreceptores/fisiologia , Microtúbulos/fisiologia , Dados de Sequência Molecular , Proteínas do Tecido Nervoso/genéticaRESUMO
We measured the synthesis of 5'-deoxyadenosylcobalamin (AdoCbl) in fibroblast extracts from patients with inherited methylmalonicacidemia due to deficient activity of the cobalamin-dependent holoenzyme, methylmalonyl-CoA mutase (EC 5.4.99.2). Previous studies with intact fibroblasts from patients whose holoenzyme deficiency was secondary to abnormal cobalamin metabolism had defined two phenotypes, one in which whole cells failed to accumulate AdoCbl and a second in which they failed to accumulate both AdoCbl and the second cobalamin coenzyme, methylcobalamin. With a broken cell assay of AdoCbl synthesis in cell extracts and the cell lines are named cbl A mutants; the other class shows severe deficiency of AdoCbl synthesis and the cell lines are named cbl B mutants. We define cbl C mutants as those in which both AdoCbl and methylcobalamin fail to accumulate in intact cells. The assay for AdoCbl synthesis is thought to measure two enzymatic activities, cob(II)alamin reductase (EC 1.6.99.9) and cob(I)alamin adenosyltransferase (EC 2.5.1.17). Subcellular fractionation studies place this combined activity in mitochondria.
Assuntos
Erros Inatos do Metabolismo dos Aminoácidos/metabolismo , Cobamidas/biossíntese , Malonatos/metabolismo , Ácido Metilmalônico/metabolismo , Fracionamento Celular , Linhagem Celular , Escuridão , Ditiotreitol/farmacologia , Fibroblastos/metabolismo , Humanos , Luz , Magnésio/farmacologia , Pele/metabolismo , Frações Subcelulares/metabolismo , Fatores de TempoRESUMO
The effect of expressing human huntingtin fragments containing polyglutamine (polyQ) tracts of varying lengths was assessed in Caenorhabditis elegans ASH sensory neurons in young and old animals. Expression of a huntingtin fragment containing a polyQ tract of 150 residues (Htn-Q150) led to progressive ASH neurodegeneration but did not cause cell death. Progressive cell death and enhanced neurodegeneration were observed in ASH neurons that coexpressed Htn-Q150 and a subthreshold dose of a toxic OSM-10::green fluorescent protein (OSM-10::GFP) fusion protein. Htn-Q150 huntingtin protein fragments formed protein aggregates in ASH neurons, and the number of ASH neurons containing aggregates increased as animals aged. ASH neuronal cell death required ced-3 caspase function, indicating that the observed cell death is apoptotic. Of interest, ced-3 played a critical role in Htn-Q150-mediated neurodegeneration but not in OSM10::GFP-mediated ASH neurodegeneration. ced-3 function was important but not essential for the formation of protein aggregates. Finally, behavioral assays indicated that ASH neurons, coexpressing Htn-Q150 and OSM10::GFP, were functionally impaired at 3 days before the detection of neurodegeneration, cell death, and protein aggregates.
Assuntos
Apoptose , Caspases , Proteínas do Tecido Nervoso/metabolismo , Neurônios Aferentes/patologia , Proteínas Nucleares/metabolismo , Peptídeos/metabolismo , Fatores Etários , Animais , Animais Geneticamente Modificados , Comportamento Animal , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans , Cisteína Endopeptidases/metabolismo , Proteínas de Helminto/metabolismo , Humanos , Proteína Huntingtina , Doença de Huntington , Proteínas do Tecido Nervoso/genética , Proteínas Nucleares/genética , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Peptídeos/genética , TatoRESUMO
Muscarinic agonist binding has been studied by the indirect method of competition between binding of agonist and 3H-antagonist. Studies of 3H-agonist binding have either been complicated by high levels of nonspecific binding or have been carried out at low concentrations of agonist, which bind only to high affinity sites. A new assay for binding of the muscarinic agonist, [3H]cismethyldioxolane, allows measurement of binding at concentrations up to 1000 nM with a high degree of specificity (92% at 18 nM, 50% at 1000 microM). Using this new binding method, it is possible not only to directly establish the validity of those observations made using competition binding studies, but also to obtain new insight into the mechanism of interaction of receptor agonist and guanine nucleotide. Specifically, data have been presented which demonstrate: 1) that binding of agonist to the high and low affinity forms of the muscarinic receptor involves two independent parallel reactions, and, in the absence of guanine nucleotides, agonist binding alone does not mediate the interconversion of the receptor from one affinity state to another, thus suggesting that high affinity receptors are present in chick heart membranes and do not require agonist binding for their formation; 2) that the interaction of agonist and guanine nucleotide with the receptor-guanine nucleotide-binding protein complex involves formation of an intermediate state in which both agonist and guanine nucleotide are bound to the receptor-guanine nucleotide-binding protein complex; and, finally, 3) that the order of binding of agonist and guanine nucleotide during formation of this intermediate state is random.
Assuntos
Dioxolanos , Dioxóis , Nucleotídeos de Guanina/fisiologia , Coração/embriologia , Receptores Muscarínicos/metabolismo , Animais , Sistema Livre de Células , Embrião de Galinha , Proteínas de Ligação ao GTP/metabolismo , Cinética , Parassimpatolíticos/farmacologia , Parassimpatomiméticos/farmacologiaRESUMO
A sensitive, reliable, and easily performed procedure is described for the prenatal and postnatal detection of inborn errors of propionate, methylmalonate, and cobalamin metabolism using cultured amniotic cells and skin fibroblasts. With this assay, control fibroblast lines incorporated a mean of 6.89 nanoatoms 14C/mg protein from [1-14C]propionate into trichloroacetic acid (TCA)-precipitable cell material in 10 h. Twenty-five mutant fibroblast lines from patients with propionicacidemia or one of the methylmalonicacidemias fixed 0.04 to 0.93 nanoatoms 14C/mg. Considerable variation was observed, both among and within discrete mutant classes, with respect to the residual amount of propionate pathway activity, possibly reflecting further molecular heterogeneity in these disorders. We applied this procedure to cultured amniotic cells from controls and 4 midtrimester pregnancies at risk for methylmalonicacidemia and diagnosed one fetus with a methylmalonyl CoA apomutase defect and 3 fetuses which were unaffected.
Assuntos
Erros Inatos do Metabolismo dos Aminoácidos/diagnóstico , Amniocentese/métodos , Malonatos/metabolismo , Ácido Metilmalônico/metabolismo , Propionatos/metabolismo , Vitamina B 12/metabolismo , Células Cultivadas , Fibroblastos , Humanos , Recém-NascidoRESUMO
An inductive interaction between the sevenless (sev) transmembrane tyrosine kinase receptor and the bride of sevenless (boss) transmembrane ligand is required for the development of the R7 photoreceptor neuron in the compound eye of Drosophila melanogaster. The boss protein is proposed to contain a large N-terminal extracellular domain, seven transmembrane segments, and a C-terminal cytoplasmic tail. The boss protein from Drosophila virilis (bossvir) retains strong amino acid identity with loss from D. melanogaster (bossmel): 73% identity in the N-terminal extracellular domain and 91% identity in the seven-transmembrane domain, including the cytoplasmic tail. By using P-element-mediated DNA transformation, the bossmel and bossvir genes were shown to rescue the D. melanogaster boss1 mutation. The expression of bossvir protein in D. melanogaster is indistinguishable from that of bossmel protein. Noncoding sequences which may regulate boss expression were identified based on their conservation during evolution. The predicted sev protein from D. virilis (sevvir) was previously shown to be 63% identical to sev from D. melanogaster (sevmel). A chimeric gene, (sevvir/mel), encoding the extracellular domain of sevvir and the cytoplasmic domain of sevmel rescues the D. melanogaster sevd2 mutation through interaction with either bossvir or bossmel.
Assuntos
Evolução Biológica , Proteínas de Drosophila , Drosophila melanogaster/genética , Drosophila/genética , Proteínas do Olho/genética , Glicoproteínas de Membrana/genética , Receptores Proteína Tirosina Quinases , Receptores de Peptídeos , Sequência de Aminoácidos , Animais , Sequência de Bases , Clonagem Molecular , DNA/genética , DNA/isolamento & purificação , Dados de Sequência Molecular , Oligodesoxirribonucleotídeos , Reação em Cadeia da Polimerase , Sequências Reguladoras de Ácido Nucleico , Mapeamento por Restrição , Homologia de Sequência de Aminoácidos , Homologia de Sequência do Ácido Nucleico , Transformação GenéticaRESUMO
Two hundred thirteen mother-baby pairs in The Gambia were studied to determine the influence of placental malaria infection and maternal hypergammaglobulinemia on transplacental antibody transfer. Antibody transfer for herpes simplex virus 1 (HSV-1), respiratory syncytial virus (RSV), and varicella-zoster virus (VZV) was significantly reduced by placental malaria infection by 69%, 58%, and 55%, respectively. Maternal hypergammaglobulinemia was associated with a significant reduction in antibody transfer for HSV-1, RSV, VZV, and pneumococcus by 89%, 90%, 91%, and 88%, respectively. In addition, placental malaria infection was associated with a significant reduction in transfer of IgG1, IgG2, and IgG4 (P<.01, P=.01, and P=.03, respectively) but not of IgG3 (P=.59). Maternal hypergammaglobulinemia significantly impaired the transfer of IgG1 and IgG2 (P=.01) but not of IgG3 or IgG4 (P=.62 and P=.59, respectively). Placental malaria infection and maternal hypergammaglobulinemia were associated with reduction in the transplacental transfer of these specific antibodies, IgG1, and IgG2 in this Gambian population.