RESUMO
Frontotemporal lobar degeneration with TDP-43 inclusions (FTLD-TDP) can typically be categorized into one of four distinct histopathologic patterns of TDP-43 pathology, types A to D. The strength of this histopathologic classification lies in the association between FTLD-TDP subtypes and various clinical and genetic features of disease. Seven cases of FTLD-TDP were identified here which were difficult to classify based on existing pathologic criteria. Distinct features common to these cases included TDP-43 aggregates over a wide neuroanatomic distribution comprised of granulofilamentous neuronal inclusions, abundant grains, and oligodendroglial inclusions. TDP-43 aggregates were phosphorylated and associated with loss of normal nuclear TDP-43 protein (nuclear clearance) but were negative for ubiquitin. Biochemical analysis confirmed the presence of insoluble and phosphorylated TDP-43 and also revealed a distinct pattern of TDP-43 C-terminal fragments relative to other FTLD-TDP subtypes. Finally, these cases were uniformly associated with a very rapid clinical course culminating in death within ~3 years of disease onset. We suggest that these cases may represent a unique clinicopathologic subtype of FTLD-TDP which we provisionally call "type E." The immature appearance of TDP-43 aggregates, widespread distribution, uniform biochemical profile and rapid clinical course highlights the clinical and pathologic variability within FTLD-TDP, and raises the possibility that type E neuropathology is the sequelae of a particularly virulent strain of TDP-43 proteinopathy.
Assuntos
Degeneração Lobar Frontotemporal/classificação , Idade de Início , Idoso , Idoso de 80 Anos ou mais , Proteínas de Ligação a DNA/metabolismo , Progressão da Doença , Imunofluorescência , Lobo Frontal/metabolismo , Lobo Frontal/patologia , Degeneração Lobar Frontotemporal/genética , Degeneração Lobar Frontotemporal/metabolismo , Degeneração Lobar Frontotemporal/patologia , Humanos , Pessoa de Meia-Idade , Fenótipo , Análise de RegressãoRESUMO
The transcriptomes from different organs and tissues of western poplar, eucalyptus, soybean and common bean were studied. The expression level of cellulose synthase genes was notably different in different types of tissues and organs in studied plants. For common bean and eucalyptus transcriptome the domination of certain cellulose synthase genes was typical. These prevailing genes made up more than 50 % of the total expression pull of cellulose synthases. On the contrary, cellulose synthase expression pulls of wes-tern poplar and soybean were distributed between multiple genes. The different expression strategies of CesA-genes may reflect a phylogenetic processes that occurred in genomes studied.
Assuntos
Eucalyptus/genética , Regulação da Expressão Gênica de Plantas , Genoma de Planta , Glucosiltransferases/genética , Glycine max/genética , Phaseolus/genética , Proteínas de Plantas/genética , Populus/genética , Arabidopsis/classificação , Arabidopsis/genética , Arabidopsis/metabolismo , Eucalyptus/classificação , Eucalyptus/metabolismo , Frutas/genética , Frutas/metabolismo , Glucosiltransferases/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala , Isoenzimas/genética , Isoenzimas/metabolismo , Família Multigênica , Especificidade de Órgãos , Phaseolus/classificação , Phaseolus/metabolismo , Filogenia , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Caules de Planta/genética , Caules de Planta/metabolismo , Populus/classificação , Populus/metabolismo , Glycine max/classificação , Glycine max/metabolismo , Especificidade da Espécie , TranscriptomaRESUMO
The current data is dedicated to the study of bioballistic and Agrobacterium-mediated transformation of finger millet with the constructs carrying the mutant alpha-tubulin gene (TUAm 1), isolated from R-biotype goosegrass (Eleusine indica L.), for the decision of problem of dinitroaniline-resistance. It was found that 10 microM of trifluralin is optimal for the selection of transgene plants of finger millet. PCR analysis of transformed lines confirmed the transgene nature of plants. The analysis of seed of T1 oftransgene lines confirmed heterozygous character of inheritance of the resistance.
Assuntos
Eleusine/efeitos dos fármacos , Eleusine/genética , Resistência a Herbicidas/genética , Herbicidas/farmacologia , Plantas Geneticamente Modificadas , Trifluralina/farmacologia , Tubulina (Proteína)/genética , Eleusine/crescimento & desenvolvimento , Genes de Plantas , Vetores Genéticos , Heterozigoto , Transformação GenéticaRESUMO
The data of Agrobacterium-mediated transformation of some Linum usitatissimum cultivars zoned on the territories of Belarus and Ukraine with the plasmid carrying chimeric GFP-TUA6 gene and nptII gene as selectable marker conferring resistance to kanamycin are presented in this study. Transformation was affected by a number of factors including optical density (OD600), time of inoculation of explants with Agrobacterium and co-culture conditions. Transgenic nature of obtained lines was confirmed by PCR analysis. Expression of GFP-TUA6 gene was detected with confocal laser scanning microscopy. The obtained transgenic lines can be used for further functional studies the role of microtubules in the processes of building the flax fibres and resistance to wind.
Assuntos
Linho , Proteínas de Fluorescência Verde/genética , Microtúbulos/ultraestrutura , Proteínas Recombinantes de Fusão/genética , Transformação Genética , Tubulina (Proteína)/genética , Agrobacterium tumefaciens/genética , Proteínas de Arabidopsis/genética , DNA de Plantas/genética , Linho/genética , Linho/ultraestrutura , Genes de Plantas , Microscopia Confocal , Microtúbulos/genética , Plantas Geneticamente Modificadas , Reação em Cadeia da PolimeraseRESUMO
The development of the C. elegans uterus provides a model for understanding the regulatory pathways that control organogenesis. In C. elegans, the ventral uterus develops through coordinated signaling between the uterine anchor cell (AC) and a ventral uterine (VU) cell. The nhr-67 gene encodes the nematode ortholog of the tailless nuclear receptor gene. Fly and vertebrate tailless genes function in neuronal and ectodermal developmental pathways. We show that nhr-67 functions in multiple steps in the development of the C. elegans uterus. First, it functions in the differentiation of the AC. Second, it functions in reciprocal signaling between the AC and an equipotent VU cell. Third, it is required for a later signaling event between the AC and VU descendants. nhr-67 is required for the expression of both the lag-2/Delta signal in the AC and the lin-12/Notch receptor in all three VU cells and their descendants, suggesting that nhr-67 may be a key regulator of Notch-signaling components. We discuss the implications of these findings for proposed developmental regulatory pathways that include the helix-loop-helix regulator hlh-2/daughterless and transcription factor egl-43/Evi1 in the differentiation of ventral uterine cell types.
Assuntos
Proteínas de Caenorhabditis elegans/fisiologia , Caenorhabditis elegans/embriologia , Receptores Citoplasmáticos e Nucleares/fisiologia , Útero/embriologia , Animais , Proteínas de Caenorhabditis elegans/genética , Diferenciação Celular , Linhagem da Célula , Ectoderma/embriologia , Feminino , Masculino , Regiões Promotoras Genéticas , Receptores Citoplasmáticos e Nucleares/genética , Cauda/anormalidades , Vulva/embriologiaRESUMO
BACKGROUND: The nuclear receptors (NRs) are an important class of transcription factors that are conserved across animal phyla. Canonical NRs consist of a DNA-binding domain (DBD) and ligand-binding domain (LBD). While most animals have 20-40 NRs, nematodes of the genus Caenorhabditis have experienced a spectacular proliferation and divergence of NR genes. The LBDs of evolutionarily-conserved Caenorhabditis NRs have diverged sharply from their Drosophila and vertebrate orthologs, while the DBDs have been strongly conserved. The NR2E family of NRs play critical roles in development, especially in the nervous system. In this study, we explore the phylogenetics and function of the NR2E family of Caenorhabditis elegans, using an in vivo assay to test LBD function. RESULTS: Phylogenetic analysis reveals that the NR2E family of NRs consists of three broadly-conserved clades of orthologous NRs. In C. elegans, these clades are defined by nhr-67, fax-1 and nhr-239. The vertebrate orthologs of nhr-67 and fax-1 are Tlx and PNR, respectively. While the nhr-239 clade includes orthologs in insects (Hr83), an echinoderm, and a hemichordate, the gene appears to have been lost from vertebrate lineages. The C. elegans and C. briggsae nhr-239 genes have an apparently-truncated and highly-diverged LBD region. An additional C. elegans NR2E gene, nhr-111, appears to be a recently-evolved paralog of fax-1; it is present in C. elegans, but not C. briggsae or other animals with completely-sequenced genomes. Analysis of the relatively unstudied nhr-111 and nhr-239 genes demonstrates that they are both expressed--nhr-111 very broadly and nhr-239 in a small subset of neurons. Analysis of the FAX-1 LBD in an in vivo assay revealed that it is not required for at least some developmental functions. CONCLUSIONS: Our analysis supports three conserved clades of NR2E receptors, only two of which are represented in vertebrates, indicating three ancestral NR2E genes in the urbilateria. The lack of a requirement for a FAX-1 LBD suggests that the relatively high level of sequence divergence for Caenorhabditis LBDs reflects relaxed selection on the primary sequence as opposed to divergent positive selection. This observation is consistent with a model in which divergence of some Caenorhabditis LBDs is allowed, at least in part, by the absence of a ligand requirement.
Assuntos
Proteínas de Caenorhabditis elegans/genética , Caenorhabditis elegans/genética , Filogenia , Receptores Citoplasmáticos e Nucleares/genética , Sequência de Aminoácidos , Animais , Dados de Sequência Molecular , Alinhamento de SequênciaRESUMO
Rabies is considered one of the oldest infectious diseases known to humans. However, the first written reports on rabies cases in the Americas did not appear until the first decade of the 18th century from Mexico. In an attempt to clarify if the disease was already present in pre-Columbian times, we searched for evidence in the Maya and Aztec cultures. Other sources of information were early manuscripts written by the conquistadors and early explorers. We did not identify any unequivocal direct evidence that the disease rabies was known in pre-Columbian Central America but sufficient circumstantial evidence is available suggesting that (bat) rabies was already present in these early times.
Assuntos
Raiva/epidemiologia , Raiva/história , Animais , América Central/epidemiologia , História do Século XV , História do Século XVI , História do Século XVII , História do Século XVIII , História Medieval , HumanosRESUMO
A two-step chromatography process for monoclonal antibody (mAb) purification from clarified cell culture supernatant (cCCS) was developed using cation exchange Multicolumn Countercurrent Solvent Gradient Purification (MCSGP) as a capture step. After an initial characterization of the cell culture supernatant the capture step was designed from a batch gradient elution chromatogram. A variety of chromatographic materials was screened for polishing of the MCSGP-captured material in batch mode. Using multi-modal anion exchange in bind-elute mode, mAb was produced consistently within the purity specification. The benchmark was a state-of-the-art 3-step chromatographic process based on protein A, anion and cation exchange stationary phases. The performance of the developed 2-step process was compared to this process in terms of purity, yield, productivity and buffer consumption. Finally, the potential of the MCSGP process was investigated by comparing its performance to that of a classical batch process that used the same stationary phase.
Assuntos
Anticorpos Monoclonais/isolamento & purificação , Biotecnologia/métodos , Imunoglobulina G/isolamento & purificação , Cromatografia Líquida/métodos , SolventesRESUMO
INTRODUCTION: The aim of this paper is to present validated patient reported outcomes for MIS Distal Metatarsal Metaphyseal Osteotomy (DMMO) in the treatment of metatarsalgia. The study aims to evaluate the DMMO procedure, report patient satisfaction with the operated foot and report any complications of this procedure. PATIENTS AND METHODS: Between 2014 and 2016, patients who had failed conservative treatment for metatarsalgia were identified in the orthopaedic outpatient clinic. Twenty four consecutive patients requiring DMMO plus/minus toe straightening were prospectively studied. Patients requiring additional procedures at the time of surgery were excluded. Patients completed the validated Manchester-Oxford Foot Questionnaire (MOXFQ) three weeks pre-operatively and 1 year postoperatively. The MOXFQ results were analysed using Paired t-tests. A supplementary question was asked regarding patient satisfaction with the operated foot. RESULTS: There were 20 women and 4 men with a mean age of 64 years (sd 8.6). Statistically significant differences were found between the pre and postoperative MOXFQ. The postoperative MOXFQ score demonstrated a poorer result for two patients, no change for two patients and improvement in 20 patients, with four of these patients recording the lowest possible score. There was a 29.5 point improvement in mean metric MOXFQ Index score. Seventy-nine percent (n = 19) of patients were satisfied or very satisfied with the operated foot. The average recoil of the metatarsal heads following DMMO was M2 4.01 mm, M3 4.55 mm, M4 4.16 mm. There was one delayed union and no non-unions. Further reported complications were a gastric bleed, pulmonary embolism (VTE), and one intra operative broken burr. CONCLUSION: Our study demonstrates a clinically important and statistically significant improvement in patient reported outcomes following DMMO, with 79% of patients satisfied or very satisfied with this procedure. The average recoil of the metatarsal heads following DMMO was M2 4.01 mm, M3 4.55 mm, M4 4.16 mm with one delayed union and no non-unions.
Assuntos
Ossos do Metatarso/cirurgia , Metatarsalgia/cirurgia , Osteotomia , Idoso , Estudos de Coortes , Feminino , Humanos , Masculino , Metatarsalgia/diagnóstico por imagem , Pessoa de Meia-Idade , Procedimentos Cirúrgicos Minimamente Invasivos , Medidas de Resultados Relatados pelo Paciente , Satisfação do PacienteRESUMO
A vampire bat, Desmodus rotundus, captured in Oaxaca, Mexico, in August 1970, was found to be infected with the epidemic strain of Venezuelan equine encephalomyelitis virus at the same time that an equine epizootic was occurring there.
Assuntos
Quirópteros , Vírus da Encefalite/isolamento & purificação , Animais , Antígenos Virais/análise , Vírus da Encefalite Equina Venezuelana/imunologia , Vírus da Encefalite Equina Venezuelana/isolamento & purificação , Testes de Inibição da Hemaglutinação , MéxicoRESUMO
The majority (90%-95%) of amyotrophic lateral sclerosis (ALS) is sporadic, and â¼50% of patients develop symptoms of frontotemporal degeneration (FTD) associated with shorter survival. The genetic polymorphism rs12608932 in UNC13A confers increased risk of sporadic ALS and sporadic FTD and modifies survival in ALS. Here, we evaluate whether rs12608932 is also associated with frontotemporal disease in sporadic ALS. We identified reduced cortical thickness in sporadic ALS with T1-weighted magnetic resonance imaging (N = 109) relative to controls (N = 113), and observed that minor allele (C) carriers exhibited greater reduction of cortical thickness in the dorsal prefrontal, ventromedial prefrontal, anterior temporal, and middle temporal cortices and worse performance on a frontal lobe-mediated cognitive test (reverse digit span). In sporadic ALS with autopsy data (N = 102), minor allele homozygotes exhibited greater burden of phosphorylated tar DNA-binding protein-43 kda (TDP-43) pathology in the middle frontal, middle temporal, and motor cortices. Our findings demonstrate converging evidence that rs12608932 may modify frontotemporal disease in sporadic ALS and suggest that rs12608932 may function as a prognostic indicator and could be used to define patient endophenotypes in clinical trials.
Assuntos
Esclerose Lateral Amiotrófica/genética , Degeneração Lobar Frontotemporal/genética , Estudos de Associação Genética , Proteínas do Tecido Nervoso/genética , Polimorfismo Genético/genética , Idoso , Alelos , Esclerose Lateral Amiotrófica/complicações , Esclerose Lateral Amiotrófica/diagnóstico por imagem , Esclerose Lateral Amiotrófica/patologia , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/patologia , Proteínas de Ligação a DNA/genética , Feminino , Degeneração Lobar Frontotemporal/diagnóstico por imagem , Degeneração Lobar Frontotemporal/etiologia , Degeneração Lobar Frontotemporal/patologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Neuroimagem , Prognóstico , RiscoRESUMO
BACKGROUND: Measurement of slow EEG activity and burst suppression are the main tasks in monitoring the effects of anaesthestics with EEG, which is often done with commercial univariate indexes such as BIS. The aim of this study was to describe the characteristics of burst suppression EEG during propofol anaesthesia using scalp electrodes and depth electrodes in the subthalamic nucleus. Specifically, we describe the electrical fields of the three EEG patterns we have previously described: the sharp wave, the burst and the spindle. METHODS: We recorded the EEG of three Parkinson patients during propofol anaesthesia from the scalp electrodes and the depth electrode implanted in the subthalamic nucleus for treating parkinsonism. RESULTS: (1) The slow waves of bursts recorded from all surface electrodes on scalp or neck with depth electrode reference are positive and have the highest amplitude in frontal electrodes, suggesting synchronous generation in the whole cerebral cortex. (2) The sharp wave and spindles have the highest amplitude at vertex. They are opposite in polarity in vertex and depth electrodes when referred to the neck electrode, suggesting generation in the sensorimotor cortex. CONCLUSIONS: Recording simultaneously EEG from the depth and scalp electrodes shows that bursts and their slow wave oscillations are synchronous in the whole cortex while spindles and sharp waves are produced by the sensorimotor cortex. The amplitude of slow waves recorded with surface electrodes is equal to the difference of the wave at two electrodes and therefore only a small part of that generated by the cortex.
Assuntos
Anestésicos Intravenosos/farmacologia , Eletroencefalografia/efeitos dos fármacos , Doença de Parkinson/cirurgia , Propofol/farmacologia , Couro Cabeludo/cirurgia , Núcleo Subtalâmico/cirurgia , Adulto , Anestesia Geral/métodos , Eletrodos Implantados , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Monitorização Intraoperatória/métodos , Couro Cabeludo/efeitos dos fármacos , Núcleo Subtalâmico/efeitos dos fármacosRESUMO
Rabies in dogs was unknown in the Americas before the arrival of the Spanish "Conquistadores". Until the mid-1980s rabies in animals and, in turn in humans, changed little from year to year, with the number of dog vaccinations reported annually rarely reaching one million. In Mexico, the national rabies control programme using mass parenteral vaccination of dogs started in 1990 with about seven million dogs vaccinated the same year. The number of vaccinated dogs exceeded 10 and 15 million in 1995 and 2005, respectively. Modern cell culture-based inactivated rabies virus vaccines were used. A key factor for the success of the dog rabies control program was the supply of potent canine rabies vaccines. Between 1990 and 2005, more than 150 million vaccine doses from 300 lots were administered. Each lot was tested for potency prior to use in the field. The required minimum content of rabies virus antigen for vaccines was 2 IU, in accord with WHO standards. Testing revealed antigen contents ranging from 3.28 to 5.59 IU. As a result of the mass dog vaccination campaigns, human rabies cases due to dog-mediated rabies decreased from 60 in 1990 to 0 in 2000. The number of rabies cases in dogs decreased from 3,049 in 1990 to 70 cases last year.
Assuntos
Doenças do Cão/prevenção & controle , Vacina Antirrábica/administração & dosagem , Vacina Antirrábica/imunologia , Raiva/veterinária , Vacinação/veterinária , Animais , Anticorpos Antivirais/sangue , Células Cultivadas , Doenças do Cão/epidemiologia , Cães , Feminino , Humanos , Masculino , México/epidemiologia , Raiva/epidemiologia , Raiva/prevenção & controle , Vacinação/métodos , Vacinação/normas , Vacinação/estatística & dados numéricosRESUMO
BACKGROUND: There are a number of different approaches to physiotherapy treatment following stroke that, broadly speaking, are based on neurophysiological, motor learning and orthopaedic principles. Some physiotherapists base their treatment on a single approach, while others use a mixture of components from a number of different approaches. OBJECTIVES: To determine if there is a difference in the recovery of postural control and lower limb function in patients with stroke if physiotherapy treatment is based on orthopaedic or neurophysiological or motor learning principles, or on a mixture of these treatment principles. SEARCH STRATEGY: We searched the Cochrane Stroke Group Trials Register (last searched May 2005), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2005), MEDLINE (1966 to May 2005), EMBASE (1980 to May 2005) and CINAHL (1982 to May 2005). We contacted experts and researchers with an interest in stroke rehabilitation. SELECTION CRITERIA: Randomised or quasi-randomised controlled trials of physiotherapy treatment approaches aimed at promoting the recovery of postural control and lower limb function in adult participants with a clinical diagnosis of stroke. Outcomes included measures of disability, motor impairment or participation. DATA COLLECTION AND ANALYSIS: Two review authors independently categorised the identified trials according to the inclusion and exclusion criteria, documented their methodological quality, and extracted the data. MAIN RESULTS: Twenty-one trials were included in the review, five of which were included in two comparisons. Eight trials compared a neurophysiological approach with another approach; eight compared a motor learning approach with another approach; and eight compared a mixed approach with another approach. A mixed approach was significantly more effective than no treatment or placebo control for improving functional independence (standardised mean difference (SMD) 0.94, 95% confidence intervals (CI) 0.08 to 1.80). There was no significant evidence that any single approach had a better outcome than any other single approach or no treatment control. AUTHORS' CONCLUSIONS: There is evidence that physiotherapy intervention, using a mix of components from different approaches, is significantly more effective than no treatment or placebo control in the recovery of functional independence following stroke. There is insufficient evidence to conclude that any one physiotherapy approach is more effective in promoting recovery of lower limb function or postural control following stroke than any other approach. We recommend that future research should concentrate on investigating the effectiveness of clearly described individual techniques and task-specific treatments, regardless of their historical or philsophical origin.
Assuntos
Biorretroalimentação Psicológica/métodos , Postura , Reabilitação do Acidente Vascular Cerebral , Adulto , Humanos , Perna (Membro)/fisiologia , Destreza Motora , Modalidades de Fisioterapia , Propriocepção/fisiologia , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
Data on selection and characterizing of finger millet Eleusine coracana (L.) Gaertn. somaclonal variants regenerated from callus culture are presented and described. Among the tested genetically stable lines the somaclonal variant SE-7 was the most interesting due to its acquired important agricultural traits, such as a higher seed and biomass yield, rapid seed germination at lower temperatures, shortening of the main plant development stages. Data analysis shows that somaclonal variability can be a source to obtain initial material for further selection of new finger millet varieties.
Assuntos
Eleusine/crescimento & desenvolvimento , Eleusine/genética , Variação Genética , Cromossomos de Plantas/genética , Germinação , Sementes/genética , Sementes/crescimento & desenvolvimento , Seleção GenéticaRESUMO
A procedure has been developed to isolate DNA fragments on a large scale. A DNA fragment of 130 base-pairs containing the strong promoter A1 of the phage T7 was purified to homogeneity in amounts of 10 mg. The procedure includes the rapid purification of gram amounts of plasmid DNA, a new, simple method to separate small DNA fragments from the vector by a phenol/water partitioning system, and a liquid-liquid PEG-dextran partition chromatography for the final purification of the fragment. The fragment was cloned in two vector systems: The vector pDS1, to1+ (1), containing an efficient terminator downstream from the promoter integration site, gives high yields, 3-4 mg plasmid DNA per liter medium. In the plasmid pWH802 (2), which is not specially designed for the amplification of a strong promoter, the integration of the promoter was possible but the yield decreased by a factor of about 50. The stability of the inserts was tested in both systems. Monomeric inserts were stable in both plasmids, multimeric inserts up to a tetramer were only stable in pWH802. Only one orientation of the fragment was found.
Assuntos
Colífagos/genética , DNA Viral/isolamento & purificação , Plasmídeos , Regiões Promotoras Genéticas , Biotecnologia/métodos , Cromatografia , Clonagem Molecular , Proteínas/análise , RNA/análiseRESUMO
By means of neutron solution scattering we determined the position and orientation of core enzyme and sigma-factor within the Escherichia coli RNA polymerase holoenzyme with the aim of improving existing models. The individual components, core enzyme (E) and sigma-factor (sigma), were highlighted by deuterium labeling and their center-to-center distances determined in the monomeric and the dimeric holoenzyme. The following distance parameters were obtained: dE1-sigma 1 = 8.6(+/- 1) nm, dE1-E2 = 11.5(+/- 1) nm, d sigma 1-sigma 2 = 12.0(+/- 0.7) nm, dE1-sigma 2 = 9(+/- 3) nm. Using a triangulation procedure the position of the sigma-factors, sigma 1 and sigma 2, were determined with respect to the mass center of the core enzyme molecules, E1 and E2, assuming a symmetrical arrangement of the holoenzyme molecules in the dimer (C2 symmetry). In addition, the orientation of the sigma-factor with respect to core enzyme was estimated by means of model calculations. The obtained model of holoenzyme depicts the sigma-factor as buried in a groove of core enzyme, probably between the large subunits beta' and beta.
Assuntos
RNA Polimerases Dirigidas por DNA/química , Escherichia coli/enzimologia , Fator sigma/química , Substâncias Macromoleculares , Modelos Moleculares , Estrutura Molecular , Nêutrons , Espalhamento de RadiaçãoRESUMO
In this paper we demonstrate that neutron small angle scattering is a suitable method to study the spatial arrangement of large specific protein-DNA complexes. We studied the complex of DNA-dependent RNA polymerase of Escherichia coli and a 130 base-pair DNA fragment containing the strong promoter A1 of bacteriophage T7. Contrast variation of the complex with deuterium allowed us to "visualize" either RNA polymerase, or DNA, or both components in situ. From the corresponding scattering curves information was derived about: (1) Conformational changes of RNA polymerase and DNA by complex formation: comparison of the scattering profiles of the isolated and complexed components showed that by specific complex formation the cross-section of RNA polymerase decreases, while the DNA fragment does not undergo a gross conformational change. (2) The spatial arrangement of RNA polymerase and DNA in the specific complex from the cross-sectional radii of gyration of the complex the normal distance dn between the centre of gravity of the RNA polymerase and the axis of the DNA fragment was derived as 5.0 (+/- 0.3) nm. On the basis of these and footprinting data a low resolution model of the RNA polymerase-promoter complex is proposed. The main feature of this model is the positioning of RNA polymerase to only one side of the DNA.
Assuntos
DNA Bacteriano/metabolismo , RNA Polimerases Dirigidas por DNA/metabolismo , Escherichia coli/enzimologia , Glicerol/farmacologia , Modelos Biológicos , Nêutrons , Conformação de Ácido Nucleico , Conformação Proteica/efeitos dos fármacos , Espalhamento de RadiaçãoRESUMO
Vampire bats were inoculated intramuscularly and subcutaneously with varying doses of rabies virus to simulate bites by rabid animals in nature. Daily saliva samples were then taken from these animals to determine whether they excreted virus and for how long. Vampire bats appear to react to rabies virus as do other animals, with variable incubation periods, some excretion of virus in the saliva, but no prolonged excretion "carrier state."
Assuntos
Quirópteros/microbiologia , Raiva/veterinária , Animais , Feminino , Masculino , México , Camundongos , Raiva/microbiologia , Vírus da Raiva/patogenicidade , Glândulas Salivares/microbiologiaRESUMO
A dog inoculated with a rabies virus isolate from the saliva of an apparently healthy Ethiopian dog was followed for more than 9 months. Saliva and blood specimens were collected three times weekly and cerebrospinal fluid weekly. Saliva samples collected on days 42 and 169 after the dog's recovery produced fatal rabies infections in mice inoculated intracerebrally.