RESUMO
Ammonia-oxidizing archaea are ubiquitous in marine and terrestrial environments and now thought to be significant contributors to carbon and nitrogen cycling. The isolation of Candidatus "Nitrosopumilus maritimus" strain SCM1 provided the opportunity for linking its chemolithotrophic physiology with a genomic inventory of the globally distributed archaea. Here we report the 1,645,259-bp closed genome of strain SCM1, revealing highly copper-dependent systems for ammonia oxidation and electron transport that are distinctly different from known ammonia-oxidizing bacteria. Consistent with in situ isotopic studies of marine archaea, the genome sequence indicates N. maritimus grows autotrophically using a variant of the 3-hydroxypropionate/4-hydroxybutryrate pathway for carbon assimilation, while maintaining limited capacity for assimilation of organic carbon. This unique instance of archaeal biosynthesis of the osmoprotectant ectoine and an unprecedented enrichment of multicopper oxidases, thioredoxin-like proteins, and transcriptional regulators points to an organism responsive to environmental cues and adapted to handling reactive copper and nitrogen species that likely derive from its distinctive biochemistry. The conservation of N. maritimus gene content and organization within marine metagenomes indicates that the unique physiology of these specialized oligophiles may play a significant role in the biogeochemical cycles of carbon and nitrogen.
Assuntos
Processos Autotróficos/genética , Crenarchaeota/genética , Genoma Arqueal/genética , Internacionalidade , Nitrogênio/metabolismo , Água do Mar/microbiologia , Diamino Aminoácidos/biossíntese , Amônia/metabolismo , Divisão Celular/genética , Crenarchaeota/citologia , Transporte de Elétrons/genética , Metabolismo Energético/genética , Evolução Molecular , Regulação da Expressão Gênica , Metagenoma/genética , Oxirredução , Fotossíntese/genética , Filogenia , RNA não Traduzido/genética , Análise de Sequência de DNA , Transcrição GênicaRESUMO
The ability to target specific sequences of DNA through oligonucleotide-based triple-helix formation provides a powerful tool for genetic manipulation. Under experimental conditions, triplex DNA can inhibit DNA transcription and replication, generate site-specific mutations, cleave DNA, and induce homologous recombination. This review describes the binding requirements for triplex formation, surveys recent advancements in the chemistry and biology of triple helices and considers several potential applications of triplex DNA for use in genetic therapy.
Assuntos
DNA/uso terapêutico , Terapia Genética/métodos , Conformação de Ácido Nucleico , Animais , Humanos , OligodesoxirribonucleotídeosRESUMO
An audit of 202 routine abdominal and pelvic ultrasound examinations was carried out to evaluate the clinical performance and interpretation of these scans by radiographers and compare them with radiologists, and to investigate the extended role of radiographers in performing these scans. Each scan was first performed by a radiographer and then repeated by the radiologist. The findings were subsequently compared and any discrepancy resolved by re-scanning the patient with or without the involvement of an independent radiologist, or by follow-up of the patient by other imaging studies. In 158 (78.2%) scans, there was complete agreement between the radiographer's and radiologist's findings. In 44 scans (21.8%), there was incomplete agreement--there were 108 abnormal findings in these scans with incomplete agreement/discrepancy in 53 abnormalities. Overall, the accuracy of radiographers was 92.0% and radiologists was 91.7%; however, the accuracy rates were 94.0% and 96.4%, respectively, when minor abnormal findings without significant influence on the patient's clinical outcome were excluded.
Assuntos
Abdome/diagnóstico por imagem , Pelve/diagnóstico por imagem , Radiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Competência Clínica , Feminino , Humanos , Masculino , Auditoria Médica , Pessoa de Meia-Idade , Estudos Prospectivos , UltrassonografiaRESUMO
INTRODUCTION: Malnutrition is a common phenomenon among the elderly and quite often related to psychosocial problems. The objective of this study was to determine malnutrition risk and its association with appetite, functional and psychosocial status among elderly Malays in an agricultural settlement, i.e. FELDA Sungai Tengi, Selangor. METHODS: A cross-sectional study was conducted among 160 subjects (men = 36.2%), with a mean age of 65.0 +/- 3.9 years, who were interviewed to obtain information on malnutrition risk and appetite using Mini Nutritional Assessment Short Form and Simplified Nutritional Appetite Questionnaire, respectively. Functional status was determined using Instrumental Activities of Daily Living (IADL), Elderly Mobility Scale (EMS) and handgrip strength. Mini Mental Status Examination (MMSE), Geriatric Depression Scale and De Jong Gierveld Loneliness Scale were used to identify cognitive impairment, depressive symptoms and loneliness status of subjects respectively. A total of 42.5% of subjects were at risk of malnutrition and 61.2% had poor appetite. The mean scores of IADL and EMS were lower in subjects at risk of malnutrition, compared to those who were not at high risk (p < 0.05 for both parameters). Multiple linear regression showed that 19.8% of malnutrition risk was predicted by poor appetite, decreased functional status (IADL) and depression. CONCLUSION: Malnutrition risk was prevalent and associated with poor appetite, functional status and psychosocial problems among the elderly subjects. The psychosocial aspect should also be incorporated in nutrition intervention programmes in order to improve mental well-being and functional independancy.
Assuntos
Apetite/fisiologia , Nível de Saúde , Desnutrição/epidemiologia , Avaliação Nutricional , População Rural/estatística & dados numéricos , Comportamento Social , Atividades Cotidianas/psicologia , Idoso , Transtornos Cognitivos/epidemiologia , Transtornos Cognitivos/psicologia , Comorbidade , Estudos Transversais , Transtorno Depressivo/epidemiologia , Transtorno Depressivo/psicologia , Feminino , Avaliação Geriátrica/métodos , Avaliação Geriátrica/estatística & dados numéricos , Humanos , Solidão/psicologia , Malásia/epidemiologia , Masculino , Desnutrição/psicologia , Pessoa de Meia-Idade , Estado Nutricional/fisiologia , Fatores de Risco , Saúde da População Rural/estatística & dados numéricos , Inquéritos e QuestionáriosRESUMO
Outbreaks of gastroenteritis associated with the consumption of raw imported half-shelled frozen oysters occurred in Singapore between 16 Dec 2003 and 04 Jan 2004. A total of 305 cases were reported with clinical symptoms of diarrhoea (94%), abdominal cramps (72%), vomiting (69%) and fever (54%). The median incubation period was 30.8h and the duration of illness was 2-3 days. The overall relative risk of oyster consumption was 14.1 (95% CI: 8.3-24.0, P<0.001). Stool and oyster samples tested negative for common bacterial pathogens, including Vibrio parahaemolyticus. However, stool samples were positive for the presence of Norovirus group II RNA via RT PCR while oyster samples indicated the presence of Norovirus particles by electron microscopy. The clinical and epidemiological features were suggestive of Norovirus gastroenteritis and were subsequently confirmed by laboratory tests of stools and implicated oysters. Steps have been taken to ensure that food outlets do not thaw frozen oysters and serve them raw.
Assuntos
Surtos de Doenças , Gastroenterite/epidemiologia , Gastroenterite/virologia , Norovirus/isolamento & purificação , Ostreidae/virologia , Intoxicação por Frutos do Mar , Adolescente , Adulto , Idoso , Animais , Estudos de Casos e Controles , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Singapura/epidemiologiaRESUMO
Triple helix-forming oligonucleotides (TFOs) can bind to polypurine/polypyrimidine regions in DNA in a sequence-specific manner. Triple helix formation has been shown to stimulate recombination in mammalian cells in both episomal and chromosomal targets containing direct repeat sequences. Bifunctional oligonucleotides consisting of a recombination donor domain tethered to a TFO domain were found to mediate site-specific recombination in an intracellular SV40 vector target. To elucidate the mechanism of triplex-induced recombination, we have examined the ability of intermolecular triplexes to provoke recombination within plasmid substrates in human cell-free extracts. An assay for reversion of a point mutation in the supFG1 gene in the plasmid pSupFG1/G144C was established in which recombination in the extracts was detected upon transformation into indicator bacteria. A bifunctional oligonucleotide containing a 30-nucleotide TFO domain linked to a 40-nucleotide donor domain was found to mediate gene correction in vitro at a frequency of 46 x 10(-)5, at least 20-fold above background and over 4-fold greater than the donor segment alone. Physical linkage of the TFO to the donor was unnecessary, as co-mixture of separate TFO and donor segments also yielded elevated gene correction frequencies. When the recombination and repair proteins HsRad51 and XPA were depleted from the extracts using specific antibodies, the triplex-induced recombination was diminished, but was either partially or completely restored upon supplementation with the purified HsRad51 or XPA proteins, respectively. These results establish that triplex-induced, intermolecular recombination between plasmid targets and short fragments of homologous DNA can be detected in human cell extracts and that this process is dependent on both XPA and HsRad51.
Assuntos
Proteínas de Ligação a DNA/genética , Proteínas de Ligação a RNA/genética , Sistema Livre de Células , Humanos , Oligonucleotídeos , Rad51 Recombinase , Recombinação Genética , Proteína de Xeroderma Pigmentoso Grupo ARESUMO
Triplex-forming oligonucleotides (TFOs) can bind to polypurine/polypyrimidine regions in DNA in a sequence-specific manner and provoke DNA repair. We have coupled a TFO to a short donor fragment of DNA that shares homology to a selected gene as a strategy to mediate gene targeting and correction. In this bifunctional oligonucleotide, the TFO domain is designed to bind the target gene and stimulate repair and recombination, with the donor domain positioned for recombination and information transfer. A series of these tethered donor-TFO (TD-TFO) molecules with donor domains of 40-44 nucleotides and TFO domains in both the purine and pyrimidine triplex motifs were tested for their ability to mediate either gene correction or mutation of a supF reporter gene contained in a SV40 shuttle vector in mammalian cells. In vitro binding assays revealed that the attachment of the donor domain via a flexible linker did not significantly alter the binding affinity of the TFO domain for the polypurine site in the supF target DNA, with equilibrium dissociation constants in the 10(-8) M range. Experiments in which the target vector and the linked TD-TFOs were pre-incubated in vitro and co-transfected into cells led to conversion frequencies approaching 1%, 4-fold greater than with the two domains unlinked. When cells that had been previously transfected with the SV40 vector were electroporated with the TD-TFOs, frequencies of base pair-specific gene correction were seen in the range of 0.04%, up to 50-fold over background and at least 3-fold over either domain alone or in unlinked combinations. Sequence conversion by the TD-TFOs was achieved using either single- or double-stranded donor domains and either triplex motif. Substitution of either domain in the TD-TFO with control sequences yielded reagents with diminished activity, as did mixtures of unlinked TFO and donor DNA segments. The boost in activity provided by the attached TFO domain was reduced in cells deficient in the nucleotide excision repair factor XPA but was restored in a subclone of these cells expressing XPA cDNA, suggesting a role for nucleotide excision repair in the pathway of triple helix-stimulated gene conversion. The ability to correct or mutate a specific target site in mammalian cells using the TD-TFO strategy may provide a useful tool for research and possibly for therapeutic applications.
Assuntos
DNA , Plasmídeos/metabolismo , Animais , Sequência de Bases , Células COS , Linhagem Celular , Reparo do DNA , Humanos , Indicadores e Reagentes , Mutação PuntualRESUMO
A total of 28 species of reptiles were investigated for Blastocystis using light microscopy and in vitro culture in biphasic egg slant medium. Blastocystis species were detected in 8 (28.6%) of these 28 species in 3 tortoises (Geochelone elephantopus, G. elegans and G. carbonaria), 3 snakes (Boiga dendrophilla, Python reticulatus and Elaphe radiata), 1 crocodile (Crocodylus porosus) and 1 iguana lizard (Cyclura cornuta). The reptilian Blastocystis appeared to be morphologically similar to B. hominis.
Assuntos
Animais de Zoológico/parasitologia , Infecções por Blastocystis/veterinária , Blastocystis/isolamento & purificação , Répteis/parasitologia , Jacarés e Crocodilos/parasitologia , Animais , Infecções por Blastocystis/epidemiologia , Meios de Cultura , Fezes/parasitologia , Iguanas/parasitologia , Singapura/epidemiologia , Serpentes/parasitologia , Tartarugas/parasitologiaRESUMO
A full-length cDNA clone encoding a zinc finger protein was isolated and sequenced. This full-length clone consists of 728 bp and has a predicted open reading frame (ORF) encoding 208 amino acids. The ORF of this polypeptide codes for the human cysteine-rich protein 2 (HCRP2) and has an amino acid sequence that is 92.8% identical to its rat homolog (RCRP2). HCRP2 was mapped to chromosome 14q32, which is a hot spot of translocation in tumor development, by fluorescent in situ hybridization (FISH).