72 resultados para sdr-like
Resumo:
We examined the effect of recombinant human growth hormone (rhGH) and/or recombinant human insulin-like growth factor-I (rhIGF-I) on regional fat loss in postmenopausal women undergoing a weight loss regimen of diet plus exercise. Twenty-seven women aged 59-79 years, 20-40% above ideal body weight, completed a 12-week program consisting of resistance training 2 days/week and walking 3 days/week, while consuming a diet that was 500 kcal/day less than that required for weight maintenance, Participants were randomly assigned in a double-blind fashion to receive rhGH (0.025 mg/kg BW/day: n=7), rhIGF-I (0.015 mg/kg BW/day: n=7), rhGH + rhIGF-I (n = 6), or placebo (PL: n = 7). Regional and whole body fat mass were determined by dual X-ray absorptiometry. Body fat distribution was assessed by the ratios of trunk fat-to-limb fat (TrF/LimbF) and trunk fat-to-total fat (TrF/TotF), Limb and trunk fat decreased in all groups (p < 0.01). For both ratios of fat distribution, the rhGH treated group experienced an enhanced loss of truncal compared to peripheral fat (p less than or equal to 0.01), with no significant change for those administered rhIGF-I or FL. There was no association between change in fat distribution and indices of cardiovascular disease risk as determined by serum lipid/lipoprotein levels and maximal aerobic capacity. These results suggest that administration of rhGH facilitates a decrease in central compared to peripheral fat in older women undertaking a weight loss program that combines exercise and moderate caloric restriction, although no beneficial effects are conferred to lipid/lipoprotein profiles, Further, the effect of rhGH is not enhanced by combining rhCH with rhIGF-I administration. In addition, rhIGF-I does not augment the loss of trunk fat when administered alone.
Resumo:
The Sm/Lsm proteins associate with small nuclear RNA to form the core of small nuclear ribonucleoproteins, required for processes as diverse as pre-mRNA splicing, mRNA degradation and telomere formation. The Lsm proteins from archaea are likely to represent the ancestral Sm/Lsm domain. Here, we present the crystal structure of the Lsm alpha protein from the thermophilic archaeon Methanobacterium thermoautrophicum at 2.0 Angstrom resolution. The Lsm alpha protein crystallizes as a heptameric ring comprised of seven identical subunits interacting via beta -strand pairing and hydrophobic interactions. The heptamer can be viewed as a propeller-like structure in which each blade consists of a seven-stranded antiparallel beta -sheet formed from neighbouring subunits. There are seven slots on the inner surface of the heptamer ring, each of which is lined by Asp, Asn and Arg residues that are highly conserved in the Sm/Lsm sequences. These conserved slots are likely to form the RNA-binding site. In archaea, the gene encoding Lsm alpha is located next to the L37e ribosomal protein gene in a putative operon, suggesting a role for the Lsm alpha complex in ribosome function or biogenesis. (C) 2001 Academic Press.
Resumo:
Endoparasitoid wasps produce maternal protein secretions, which are transported into the body of insect hosts at oviposition to regulate host physiology for successful development of their offspring. Venturia canescens calyx fluid contains so-called virus-like particles (VLPs) that are essential for immune evasion of the developing parasitoid inside the host. VLPs consist of four major proteins. In this paper, we describe the isolation and molecular cloning of a gene (vlp2) that is a constituent of VLPs and discuss its possible role in VLP structure and function.
Resumo:
Maternal protein secretions from endoparasitoid wasps are evolutionary adaptations to regulate host physiology as part of an extended wasp phenotype. Virus-like particles (VLPs) produced in the calyx region of Venturia canescens wasps are involved in immune evasion of the developing parasitoid inside the host. In contrast to polydnaviruses (PDVs), VcVLPs are devoid of any nucleic acids. To understand the role of these particles in the regulation of host physiology and phylogenetic relationship between VLPs and PDVs, it is essential to identify particle proteins. In this paper, we describe the isolation and molecular cloning of a neprilysin-like gene (VcNEP) coding for a 94 kDa VcVLP protein and discuss its possible role in host regulation.
Resumo:
We demonstrate that the dynamics of an autonomous chaotic laser can be controlled to a periodic or steady state under self-synchronization. In general, past the chaos threshold the dependence of the laser output on feedback applied to the pump is submerged in the Lorenz-like chaotic pulsation. However there exist specific feedback delays that stabilize the chaos to periodic behavior or even steady state. The range of control depends critically on the feedback delay time and amplitude. Our experimental results are compared with the complex Lorenz equations which show good agreement.
Resumo:
The applicability of image calibration to like-values in mapping water quality parameters from multitemporal images is explored, Six sets of water samples were collected at satellite overpasses over Moreton Bay, Brisbane, Australia. Analysis of these samples reveals that waters in this shallow bay are mostly TSS-dominated, even though they are occasionally dominated by chlorophyll as well. Three of the images were calibrated to a reference image based on invariant targets. Predictive models constructed from the reference image were applied to estimating total suspended sediment (TSS) and Secchi depth from another image at a discrepancy of around 35 percent. Application of the predictive model for TSS concentration to another image acquired at a time of different water types resulted in a discrepancy of 152 percent. Therefore, image calibration to like-values could be used to reliably map certain water quality parameters from multitemporal TM images so long as the water type under study remains unchanged. This method is limited in that the mapped results could be rather inaccurate if the water type under study has changed considerably. Thus, the approach needs to be refined in shallow water from multitemporal satellite imagery.
Resumo:
A dendritic cell (DC) imbalance with a marked deficiency in CD4(-)8(+) DC occurs in non-obese diabetic (NOD) mice, a model of human autoimmune diabetes mellitus. Using a NOD congenic mouse strain, we find that this CD4(-)8(+) DC deficiency is associated with a gene segment on chromosome 4, which also encompasses non-MHC diabetes susceptibility loci. Treatment of NOD mice with fms-like tyrosine kinase 3 ligand (FL) enhances the level of CD4(-)8(+) DC, temporarily reversing the DC subtype imbalance. At the same time, fms-like tryosine kinase 3 ligand treatment blocks early stages of the diabetogenic process and with appropriately timed administration can completely prevent diabetes development. This points to a possible clinical use of FL to prevent autoimmune disease.
Resumo:
An improved method for counting virus and virus like particles by electron microscopy (EM) was developed. The procedure involves the determination of the absolute concentration of pure or semi-pure particles once deposited evenly on EM grids using either centrifugation or antibody capture techniques. The counting of particles was done with a Microfiche unit which enlarged approximately 50 x the image of particles on a developed negative film which had been taken at a relatively low magnification (2500 x) by EM. Initially, latex particles of a known concentration were counted using this approach, to prove the accuracy of the technique. The latex particles were deposited evenly on an EM grid using centrifugation (Modified Beckmen EM-90 Airfuge technique). Subsequently, recombinant Bluetongue virus (BTV) core-like particles (CLPs) captured by a Monoclonal antibody using a hovel sample loading method were counted by the Microfiche unit method and by a direct EM method. Comparison of the simplified counting method developed with a conventional method, showed good agreement. The method is simple, accurate, rapid, and reproducible when used with either pure particles or with particles from crude cell culture extracts.
Resumo:
Insulin-like growth factor I has similar mitogenic effects to insulin, a growth factor required by most cells in culture, and it can replace insulin in serum-free formulations for some cells. Chinese Hamster Ovary cells grow well in serum-free medium with insulin and transferrin as the only exogenous growth factors. An alternative approach to addition of exogenous growth factors to serum-free medium is transfection of host cells with growth factor-encoding genes, permitting autocrine growth. Taking this approach, we constructed an IGF-I heterologous gene driven by the cytomegalovirus promoter, introduced it into Chinese Hamster Ovary cells and examined the growth characteristics of Insulin-like growth factor I-expressing clonal cells in the absence of the exogenous factor. The transfected cells secreted up to 500 ng/10(6) cells/day of mature Insulin-like growth factor I into the conditioned medium and as a result they grew autonomously in serum-free medium containing transferrin as the only added growth factor. This growth-stimulating effect, observed under both small and large scale culture conditions, was maximal since no further improvement was observed in the presence of exogenous insulin.
Resumo:
Systemic Cowdry Type A inclusions (CAs) were observed in a moribund Cherax destructor collected at an aquaculture farm in South Australia. Inclusions were most common in the gills and were associated with multifocal necrosis of the main gill axis and lamellae. The hepatopancreas was necrotic; however, only one CA was observed in the interstitial tissues. CAs were associated with necrosis in the abdominal and gut musculature. CAs were also observed in the spongy connective tissues and the epicardium. Empty capsids (17.5 +/- 0.5 nm) and microfilaments were most commonly observed within these inclusions by transmission electron microscopy. Complete icosahedral viral particles (20.8 +/- 1.2 nm) were difficult to distinguish within the viroplasm, but were visualised better in aggregates between the viroplasm and the inner nuclear membrane. The nucleolus was closely associated with the developing viroplasm, and was hypertrophied and segregated into its fibrillar and granular components. The virus was named Cherax destructor systemic parvo-like virus (CdSPV) on the basis of its histopathology, cytopathology and morphology. CdSPV is the first systemic virus described in a freshwater crayfish.
Resumo:
The production of Long-R-3-IGF-1 (an IGF-1 fusion analog) by constant-rate, fed-batch fermentation of Escherichia coli yielded 2.6 g fusion protein/L, corresponding to an actual IGF-1 concentration of 2.2 g/L. A novel strategy employing three distinct feeding stages was developed which raised product concentration to 4.3 g/L (3.6 g/L of IGF-1) while minimising glucose and acetate accumulation. This improved productivity was not accompanied by an increase in inclusion body size.