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This paper undertakes a literature review of psychological, Educational Learning Strategies, and Models during the COVID-19 Pandemic. It examines data from 359 publications relating to this subject, published on the Web of Science, Scopus, and ScienceDirect between 2020 and 2021 using bibliometric analysis adapted with VOSviewer software. The review discusses the following approaches (keywords, authors, references (research papers), research work, countries, and research institutions). It concluded that bibliometric analysis is fundamental for detailing the theoretical literature and developing an integrated theoretical framework for psychological and Educational Learning Strategies. The psychological impact on students and potential stress needs to be closely monitored and evaluated, to plan effective policies while adopting these pedagogical approaches.
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BACKGROUND: Primary microcephaly (MCPH) is a genetically heterogeneous disorder showing an autosomal recessive mode of inheritance. Affected individuals present with head circumferences more than three SDs below the age- and sex-matched population mean, associated with mild to severe mental retardation. Five genes (MCPH1, CDK5RAP2, ASPM, CENPJ, STIL) and two genomic loci, MCPH2 and MCPH4, have been identified so far. METHODS AND RESULTS: In this study, we investigated all seven MCPH loci in patients with primary microcephaly from 112 Consanguineous Iranian families. In addition to a thorough clinical characterisation, karyotype analyses were performed for all patients. For Homozygosity mapping, microsatellite markers were selected for each locus and used for genotyping. Our investigation enabled us to detect homozygosity at MCPH1 (Microcephalin) in eight families, at MCPH5 (ASPM) in thirtheen families. Three families showed homozygosity at MCPH2 and five at MCPH6 (CENPJ), and two families were linked to MCPH7 (STIL). The remaining 81 families were not linked to any of the seven known loci. Subsequent sequencing revealed eight, 10 and one novel mutations in Microcephalin, ASPM and CENPJ, respectively. In some families, additional features such as short stature, seizures or congenital hearing loss were observed in the microcephalic patient, which widens the spectrum of clinical manifestations of mutations in known microcephaly genes. CONCLUSION: Our results show that the molecular basis of microcephaly is heterogeneous; thus, the Iranian population may provide a unique source for the identification of further genes underlying this disorder.
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Microcefalia/genética , Microcefalia/patologia , Adolescente , Adulto , Idoso , Proteínas de Ciclo Celular , Criança , Pré-Escolar , Proteínas do Citoesqueleto , Análise Mutacional de DNA , Família , Feminino , Genes Recessivos/genética , Loci Gênicos/genética , Genótipo , Humanos , Irã (Geográfico) , Cariotipagem , Masculino , Metáfase/genética , Pessoa de Meia-Idade , Mutação/genética , Proteínas do Tecido Nervoso/genética , Prófase/genética , Adulto JovemRESUMO
Haemophilia A (HA) is an X-linked recessive bleeding disorder caused by mutations in the factor VIII gene (F8), which encodes factor VIII (FVIII) protein, a plasma glycoprotein, that plays an important role in the blood coagulation cascade. In the present study, our aim was to identify F8 gene mutations in HA patients from Jordan. One hundred and seventy-five HA patients from 42 unrelated families were included in this study. Among these patients, 117 (67%) had severe HA, 13 (7%) had moderate HA and 45 (26%) had mild HA. Severe patients were first tested for intron-22 inversion using long range polymerase chain reaction (PCR), then negative patients were tested for intron-1 inversion using PCR. Sequencing for the entire F8 gene was performed for all severe HA patients who were found negative for intron-22 and -1 inversions and it was also performed for moderate and mild HA patients. HA causative mutations were identified in all patients. Intron-22 and -1 inversions were detected in 52% and 2% of families respectively. Beside these two mutations, 19 different mutations were identified, which include 15 missense and four frameshift mutations. Five novel mutations were identified including one frameshift and four missense mutations. No large deletions or nonsense mutations were detected in patients who participated in this study. Only 17 patients with severe HA were found positive for FVIII inhibitors. The data presented will play an important role for genetic counselling and health care of HA patients in Jordan.
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Fator VIII/genética , Hemofilia A/genética , Mutação , Adolescente , Adulto , Inibidores dos Fatores de Coagulação Sanguínea/análise , Criança , Pré-Escolar , Análise Mutacional de DNA , Mutação da Fase de Leitura/genética , Humanos , Lactente , Recém-Nascido , Íntrons/genética , Jordânia , Masculino , Pessoa de Meia-Idade , Mutação de Sentido Incorreto/genética , Reação em Cadeia da Polimerase , Análise de Sequência de DNA/métodos , Adulto JovemRESUMO
After a sinus lifting procedure, the compartment around the implants under the sinus mucosal lining in the sinus floor is filled with a blood clot from surrounding bleeding. The aim of this study was to evaluate the feasibility of bone formation following graftless sinus lifting with the simultaneous placement of dental implants. Thirty graftless sinus lifting procedures were performed and 72 dental implants placed in 18 consecutive patients, using the lateral window approach. Clinical and radiological follow-up was conducted throughout the 6-month healing period. Biopsies of 30 cases were collected at 6 months post-treatment: 15 biopsies were taken from the newly formed bone near the basal floor and 15 from the newly formed bone near the elevated membrane. New bone consolidation in the maxillary sinus was apparent radiologically and histologically at 6 months after sinus augmentation, providing an average 6.14±1.34mm of bone-gain. Based on histological analysis and histomorphometric data, the consolidated bone in the augmented sinus comprised 56.7±11.9% to 59.9±13.4% vital bone tissue. Out of the 72 implants placed, only four failed, indicating a 94% overall implant survival rate. Based on this case series, blood clot can be considered autologous osteogenic graft material, to which osteoprogenitors can migrate, differentiate, and regenerate bone.
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Implantação Dentária Endóssea , Seio Maxilar/diagnóstico por imagem , Osteogênese , Levantamento do Assoalho do Seio Maxilar/métodos , Adulto , Implantes Dentários , Falha de Restauração Dentária/estatística & dados numéricos , Estudos de Viabilidade , Feminino , Seguimentos , Humanos , Masculino , Seio Maxilar/fisiologia , Pessoa de Meia-Idade , Resultado do TratamentoRESUMO
Introduction:this study aimed to compare the effectiveness of mindfulness and emotion regulation training in the reduction of marital conflicts. Methodology:the present evaluation was a quasi-experimental study with a pretest-posttest design and a control group. The population consisted of all clients who referred to Moein Counseling Center in Alborz province (Spring 2014) due to marital problems. Using the simple random sampling method, 45 married people were selected as the sample and divided into two experimental groups (15 participants in each) and a control group (15 participants). Mindfulness training sessions were held for the first experimental group and emotion regulation training sessions were held for the second experimental group while, the participants in the control group did not receive any training. The Marital Conflicts Questionnaire was used for data collection and the obtained data were analyzed through descriptive statistics and analysis of covariance. Results: the results confirmed the main hypothesis of this study regarding the effectiveness of mindfulness and emotion regulation training in reduction of marital conflicts (p<0.001, F=43.41). Discussion and conclusion: there was a significant difference between mindfulness training and emotion regulation training in the reduction of marital conflicts; thus, compared to the mindfulness training, emotion regulation training can be considered a more effective treatment of marital conflicts.
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The authors used a Saudi context to verify the cross-cultural generality of findings (A. Rodrigues & K. L. Lloyd, 1998) reported for U.S. and Brazilian samples in which compliant behavior caused by reward, informational, and referent influences was perceived as more controllable and more internal than compliant behavior resulting from legitimate, expert, and coercive influences. This differential attribution led, in turn, to different affective and behavioral responses. In the present study, cognitive and affective reactions of Saudi students were measured with regard to compliant behavior (leading to a good outcome or a bad outcome) caused by each of the 6 bases of power described by B. H. Raven (1965). As expected, power bases had significant effects. However, when the outcome of the compliant behavior was bad, compliant behavior caused by a coercive influence led to the perception of more internality and controllability. Also--and not found in previous studies--the perception of less internality and controllability of compliant behavior was caused by an informational influence. Findings are discussed in the light of related research and Saudi cultural characteristics.
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Cultura , Poder Psicológico , Ira , Brasil , Comparação Transcultural , Feminino , Humanos , Masculino , Arábia Saudita , Estados UnidosRESUMO
The authors report three case stories of patients who experienced a transient syndrome consisting of headache with neurologic al deficits and CSF lymphocytic pleocytosis (HaNDL). The diagnostic criteria for this benign syndrome are presented and differential diagnoses are discussed.
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Cefaleia/diagnóstico , Linfocitose/diagnóstico , Doenças do Sistema Nervoso/diagnóstico , Adulto , Afasia/líquido cefalorraquidiano , Afasia/complicações , Afasia/diagnóstico , Diagnóstico Diferencial , Disartria/líquido cefalorraquidiano , Disartria/complicações , Disartria/diagnóstico , Feminino , Cefaleia/líquido cefalorraquidiano , Cefaleia/complicações , Humanos , Linfocitose/líquido cefalorraquidiano , Linfocitose/complicações , Masculino , Doenças do Sistema Nervoso/líquido cefalorraquidiano , Doenças do Sistema Nervoso/complicações , Paresia/líquido cefalorraquidiano , Paresia/complicações , Paresia/diagnóstico , SíndromeRESUMO
Perfluoro-n-octane (PFO) is commonly used in vitreoretinal surgery. In this case report, we present a 35-year-old patient with retained PFO up to 9 years after par plana vitrectomy. Post-operatively, PFO bubbles occupied 15% of the anterior chamber (AC). Follow-up over 9 years, consistently showed a quiet AC, normal intraocular pressure and endothelial cell counts remained stable. Until date, the patient has been under observation and there have been no ocular symptoms or side-effects. Residual PFO that inadvertently remains in the AC can be well- tolerated, without side-effects for up to 9 years.
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Câmara Anterior/efeitos dos fármacos , Tamponamento Interno , Fluorocarbonos/uso terapêutico , Descolamento Retiniano/cirurgia , Cirurgia Vitreorretiniana , Contagem de Células , Endotélio Corneano/patologia , Fluorocarbonos/toxicidade , Humanos , Masculino , Acuidade Visual , Adulto JovemRESUMO
Coronary stenosis due to atherosclerosis, the primary cause of coronary artery disease, is generally treated by balloon dilatation and stent implantation, which can result in damage to the endothelial lining of blood vessels. This leads to the restenosis of the lumen as a consequence of migration and proliferation of smooth muscle cells (SMCs). Nitric oxide (NO), which is produced and secreted by vascular endothelial cells (ECs), is a central anti-inflammatory and anti-atherogenic player in the vasculature. The goal of the present study was to develop an enzymatically active surface capable of converting the prodrug l-arginine, to the active drug, NO, thus providing a targeted drug delivery interface. NO synthase (NOS) was chemically immobilized on the surface of a stainless steel carrier with preservation of its activity. The ability of this functionalized NO-producing surface to prevent or delay processes involved in restenosis and thrombus formation was tested. This surface was found to significantly promote EC adhesion and proliferation while inhibiting that of SMCs. Furthermore, platelet adherence to this surface was markedly inhibited. Beyond the application considered here, this approach can be implemented for the local conversion of any systemically administered prodrug to the active drug, using catalysts attached to the surface of the implant.
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Reestenose Coronária/patologia , Enzimas Imobilizadas/metabolismo , Óxido Nítrico Sintase/metabolismo , Aço Inoxidável/farmacologia , Trombose/patologia , Animais , Biocatálise/efeitos dos fármacos , Adesão Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Endoteliais/citologia , Células Endoteliais/efeitos dos fármacos , Estabilidade Enzimática/efeitos dos fármacos , Humanos , Camundongos , Miócitos de Músculo Liso/citologia , Miócitos de Músculo Liso/efeitos dos fármacos , Adesividade Plaquetária/efeitos dos fármacos , Soroalbumina Bovina/metabolismo , Stents , Propriedades de SuperfícieRESUMO
Levetiracetam is an anticonvulsant which is assumed to act by modulating neurotransmitter release via binding to the vesicle protein SV2A. This could have an impact on signalling in the pain pathway. The aim of this study was to test the analgesic effect of levetiracetam in central pain in multiple sclerosis. This was a randomized, double-blind, placebo-controlled, cross-over trial with levetiracetam 3000 mg/day versus placebo (6-week treatment periods). Patients with multiple sclerosis, symptoms and signs complying with central neuropathic pain and pain symptoms for more than 6 months, as well as pain intensity of more than 4 on a 0 to 10-point numeric rating scale were included in the study. The primary outcome measure was pain relief at the end of each treatment period as measured on a 6-point verbal scale. Eighty-nine patients were screened for participation and 30 patients entered the study. Twenty-seven patients were included in the data analysis. There were no differences in the ratings of pain relief (levetiracetam 2.4 vs. placebo 2.1, p = 0.169), total pain intensity (levetiracetam 5.3 vs. placebo 5.7, p = 0.147) or any of the other outcome measures (p = 0.086-0.715) in the total sample of patients. However, there was significant reduction of pain, increased pain relief and/or more favourable pain relief with levetiracetam than with placebo in patients with lancinating or without touch-evoked pain (p = 0.025-0.046). This study found no effect of the anticonvulsant levetiracetam in non-selected patients with central pain in multiple sclerosis, but an effect in subgroups with specific pain symptoms was indicated.
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Anticonvulsivantes/administração & dosagem , Esclerose Múltipla/complicações , Neuralgia/tratamento farmacológico , Neuralgia/etiologia , Piracetam/análogos & derivados , Adulto , Analgésicos/administração & dosagem , Dor Crônica/tratamento farmacológico , Dor Crônica/etiologia , Estudos Cross-Over , Feminino , Humanos , Hiperalgesia/tratamento farmacológico , Hiperalgesia/etiologia , Levetiracetam , Masculino , Pessoa de Meia-Idade , Limiar da Dor/efeitos dos fármacos , Satisfação do Paciente , Piracetam/administração & dosagem , Placebos/administração & dosagem , Falha de TratamentoRESUMO
BACKGROUND: Epidemiologic studies have suggested different prevalence of neuromyelitis optica (NMO) in different ethnic groups. However, data on the incidence and prevalence of NMO in Caucasians are scarce. OBJECTIVE: To estimate the incidence and prevalence of NMO in a predominantly Caucasian population based on the Wingerchuk 2006 criteria. METHODS: The study was a population-based retrospective case series with longitudinal follow-up. Patients with multiple sclerosis (MS), optic neuritis (ON), acute transverse myelitis (TM), and NMO from the 4 neurology and 3 ophthalmology departments in the Region of Southern Denmark having been diagnosed between 1998 and 2008 were investigated. Patients were included based on 1) episodes of ON or TM and 2) an initial brain MRI not diagnostic for MS. An immunofluorescence assay was used to determine aquaporin-4 (AQP-4) antibodies. RESULTS: A total of 477 patients with MS, TM, or ON were evaluated: 163 fulfilled the inclusion criteria, 42 (26%) qualified for the diagnosis of NMO, 26 (62.0%) of these were AQP4 antibody positive. All except one were Caucasian, the female:male ratio was 2.8:1, and mean age at onset was 35.6 years (range 15-64 years). The clinical presentation was heterogeneous including TM, longitudinally extensive TM, ON, and brainstem syndromes. The yearly incidence rate of NMO in the population was estimated to be 0.4 per 10(5) person-years (95% confidence interval [CI] 0.30-0.54) and the prevalence was 4.4 per 10(5) (95% CI 3.1-5.7). CONCLUSIONS: Despite being a rare disease, NMO is more common in a Caucasian population than earlier believed.
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Neuromielite Óptica/epidemiologia , População Branca , Adolescente , Adulto , Idoso , Dinamarca/epidemiologia , Feminino , Seguimentos , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Neuromielite Óptica/diagnóstico , Prevalência , Estudos Retrospectivos , Inquéritos e QuestionáriosRESUMO
The genes for hsp70 (or dnaK) have been cloned and sequenced from Rhizobium meliloti and Pseudomonas cepacia, two bacterial species belonging to the alpha- and beta-subdivisions of gram-negative proteobacteria, respectively. On the basis of global alignment of HSP70 proteins, several sequence signatures have been identified that are distinctive of mitochondrial homologs and gram-negative proteobacteria on the one hand and the chloroplasts and cyanobacteria on the other. Detailed phylogenetic analyses of HSP70 sequences from various eubacteria and eukaryotic organellar and cytosolic homologs support the inference regarding the origin of mitochondria from a member of the alpha-proteobacteria and of chloroplasts from cyanobacteria. The analysis presented here also suggests a monophyletic origin of the mitochondrial homologs.
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Burkholderia cepacia/genética , Proteínas de Escherichia coli , Genes Bacterianos/genética , Proteínas de Choque Térmico HSP70/genética , Sinorhizobium meliloti/genética , Sequência de Aminoácidos , Burkholderia cepacia/classificação , Cloroplastos/genética , Clonagem Molecular , Sequência Conservada , Cianobactérias/genética , Bactérias Gram-Negativas/classificação , Bactérias Gram-Negativas/genética , Mitocôndrias/genética , Dados de Sequência Molecular , Filogenia , Homologia de Sequência de Aminoácidos , Sinorhizobium meliloti/classificaçãoRESUMO
A 5.0-kb region containing the hsp70 (dnaK) gene was cloned from Mycoplasma capricolum and sequenced. In addition to the hsp70 gene, this sequence region also contained the complete sequences for the grpE and orfA genes and partial sequences for the clpB and dnaJ genes. The order of the above gene sequences in the cloned fragment was found to be clpB-orfA-grpE-hsp70-dnaJ, which is similar to the order seen in various other gram-positive groups of bacteria. The Hsp70 homologs from two mycoplasma species, Mycoplasma capricolum and Mycoplasma genitalium, contain a number of sequence signatures, including the absence of a large insert in the N-terminal quadrant, that are characteristics of the homologs from gram-positive bacteria and archaebacteria. A detailed phylogenetic analysis based on Hsp70 sequences was also performed. In neighbor-joining and parsimony trees based on Hsp70 sequences, both mycoplasma species branched with the low-G + C-content gram-positive group of bacteria (e.g., Lactobacillus and Erysipelothrix species) in 87% and 96% of the bootstrap replicates, respectively, indicating their close evolutionary relationship to this group. The phylogenetic trees based on Hsp70 sequences show a polyphyletic branching of archaebacteria with the gram-postive species, which is statistically strongly favored.
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Clonagem Molecular , Proteínas de Choque Térmico HSP70/genética , Mycoplasma/classificação , Mycoplasma/genética , Sequência de Aminoácidos , Archaea/genética , Proteínas de Bactérias/genética , Composição de Bases , Sequência de Bases , Proteínas de Ligação ao Cálcio/genética , Proteínas de Escherichia coli , Bactérias Gram-Positivas/genética , Proteínas de Choque Térmico HSP40 , Proteínas de Choque Térmico/genética , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase , Mapeamento por Restrição , Alinhamento de SequênciaRESUMO
The 70-kDa heat shock protein (hsp70) sequences define one of the most conserved proteins known to date. The hsp70 genes from Deinococcus proteolyticus and Thermomicrobium roseum, which were chosen as representatives of two of the most deeply branching divisions in the 16S rRNA trees, were cloned and sequenced. hsp70 from both these species as well as Thermus aquaticus contained a large insert in the N-terminal quadrant, which has been observed before as a unique characteristic of gram-negative eubacteria and eukaryotes and is not found in any gram-positive bacteria or archaebacteria. Phylogenetic analysis of hsp70 sequences shows that all of the gram-negative eubacterial species examined to date (which includes members from the genera Deinococcus and Thermus, green nonsulfur bacteria, cyanobacteria, chlamydiae, spirochetes, and alpha-, beta-, and gamma-subdivisions of proteobacteria) form a monophyletic group (excluding eukaryotic homologs which are derived from this group via endosybitic means) strongly supported by the bootstrap scores. A closer affinity of the Deinococcus and Thermus species to the cyanobacteria than to the other available gram-negative sequences is also observed in the present work. In the hsp7O trees, D. proteolyticus and T. aquaticus were found to be the most deeply branching species within the gram-negative eubacteria. The hsp70 homologs from gram-positive bacteria branched separately from gram-negative bacteria and exhibited a closer relationship to and shared sequence signatures with the archaebacteria. A polyphyletic branching of archaebacteria within gram-positive bacteria is strongly favored by different phylogenetic methods. These observations differ from the rRNA-based phylogenies where both gram-negative and gram-positive species are indicated to be polyphyletic. While it remains unclear whether parts of the genome may have variant evolutionary histories, these results call into question the general validity of the currently favored three-domain dogma.
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Bactérias/classificação , Proteínas de Bactérias/genética , Proteínas de Choque Térmico HSP70/genética , Sequência de Aminoácidos , Animais , Bactérias/genética , Proteínas de Bactérias/classificação , Sequência de Bases , Clonagem Molecular , Códon , DNA Bacteriano , Bactérias Gram-Negativas/classificação , Bactérias Gram-Negativas/genética , Bactérias Gram-Positivas/classificação , Bactérias Gram-Positivas/genética , Proteínas de Choque Térmico HSP70/classificação , Humanos , Dados de Sequência Molecular , Filogenia , Homologia de Sequência de AminoácidosRESUMO
The genes for two different 70-kDa heat shock protein (HSP70) homologs have been cloned and sequenced from the protozoan Giardia lamblia. On the basis of their sequence features, one of these genes corresponds to the cytoplasmic form of HSP70. The second gene, on the basis of its characteristic N-terminal hydrophobic signal sequence and C-terminal endoplasmic reticulum (ER) retention sequence (Lys-Asp-Glu-Leu), is the equivalent of ER-resident GRP78 or the Bip family of proteins. Phylogenetic trees based on HSP70 sequences show that G. lamblia homologs show the deepest divergence among eukaryotic species. The identification of a GRP78 or Bip homolog in G. lamblia strongly suggests the existence of ER in this ancient eukaryote. Detailed phylogenetic analyses of HSP70 sequences by boot-strap neighbor-joining and maximum-parsimony methods show that the cytoplasmic and ER homologs form distinct subfamilies that evolved from a common eukaryotic ancestor by gene duplication that occurred very early in the evolution of eukaryotic cells. It is postulated that because of the essential "molecular chaperone" function of these proteins in translocation of other proteins across membranes, duplication of their genes accompanied the evolution of ER or nucleus in the eukaryotic cell ancestor. The presence in all eukaryotic cytoplasmic HSP70 homologs (including the cognate, heat-induced, and ER forms) of a number of autapomorphic sequence signatures that are not present in any prokaryotic or organellar homologs provides strong evidence regarding the monophyletic nature of eukaryotic lineage. Further, all eukaryotic HSP70 homologs share in common with the Gram-negative group of eubacteria a number of sequence features that are not present in any archaebacterium or Gram-positive bacterium, indicating their evolution from this group of organisms. Some implications of these findings regarding the evolution of eukaryotic cells and ER are discussed.
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Retículo Endoplasmático , Células Eucarióticas , Genes de Protozoários , Giardia lamblia/genética , Proteínas de Choque Térmico/genética , Sequência de Aminoácidos , Animais , Evolução Biológica , Clonagem Molecular , Dados de Sequência Molecular , Filogenia , Alinhamento de Sequência , Homologia de Sequência de AminoácidosRESUMO
Giardia lamblia trophozoites contain a complex endomembrane system as demonstrated by fluorescence and cryoelectron microscopy. The endomembrane system was weakly detected in live cells using the fluorescent membrane dye 3,3'-dihexyloxacarbocyanine iodide. The definitive identification of endoplasmic reticulum required the development of a molecular label. We expressed Giardial Bip in Escherichia coli and raised a polyclonal antibody to the purified protein. In western blots, the antibody was specific for Giardial Bip and did not react with human, monkey and rodent homologs. By immunofluorescence microscopy in methanol fixed cells the antibody visualized tubular structures and other subcellular components that required characterization by electron microscopy. Using cryotechniques we directly demonstrate the presence of a complex endomembrane system at the ultrastructural level. In conjunction with Bip immunogold labeling of cryosections we identify: (1) endoplasmic reticulum cisternae and tubules; (2) stacked perinuclear membranes; and (3) Bip presence in the nuclear envelope. Both the endoplasmic reticulum and nuclear envelope were found either with or without a cleft region suggesting each may contain common specialized sub-regions. In stacked perinuclear membranes, which may represent either multilamellar endoplasmic reticulum or a Golgi apparatus, Bip labeling was restricted to peripheral layers, also suggesting specialized sub-regions. Labeled endomembrane systems could be observed associated with microtubule structures, including axonemes and the adhesive disk. The presence of an extensive endomembrane system in Giardia lamblia, which represents one of the earliest diverging eukaryotic species, supports the view that both the nucleus and endomembrane system co-evolved in a common ancestor of eukaryotic cells.
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Retículo Endoplasmático/ultraestrutura , Giardia lamblia/ultraestrutura , Proteínas de Choque Térmico/análise , Animais , Crioultramicrotomia , Humanos , Imuno-HistoquímicaRESUMO
To better understand the genetic controls of leaf senescence, a tobacco (Nicotiana tabacum L. cv. SR1) mRNA that is up-regulated during senescence was isolated by the cDNA-amplified restriction fragment polymorphism method and the cDNA was cloned. The mRNA coded for the early light-induced protein (ELIP), a member of the chlorophyll a/b-binding protein family that has been implicated in assembly or repair of the photosynthetic machinery during early chloroplast development and abiotic stress. A protein antigenically recognized by antibodies to ELIP appeared during senescence with kinetics similar to those of its mRNA. The mRNA, designated ELIP-TOB, was detected earlier when senescence was enhanced by leaf detachment and treatment with 1-amino-cyclopropane-1-carboxylic acid, and was detected later when senescence was retarded by benzyladenine. However, no ELIP-TOB mRNA was seen in the dark even though senescence was accelerated under these conditions. Furthermore, water stress and anaerobiosis stimulated the appearance of ELIP-TOB mRNA before losses of chlorophyll could be detected. We discuss the conditions that may lead to the up-regulation of ELIP-TOB during senescence and speculate as to the role of the gene product in this terminal phase of leaf development.