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111.
112.
Heterodimerization of a functional GABAB receptor is mediated by parallel coiled-coil alpha-helices. 总被引:3,自引:0,他引:3
A detailed understanding of GABAB receptor assembly is an important issue in view of its role as attractive target for treatment of epilepsy, anxiety, depression, cognitive defects, and nociceptive disorders. Heteromerization of GABAB-R1 and GABAB-R2 subunits is a prerequisite for the formation of a functional GABAB receptor. Each individual subunit contains one stretch of approximately 30 amino acid residues within its intracellular C-terminal domain that mediates heteromer formation. To investigate the mechanism of the GABAB-R1/GABAB-R2 interaction and to assess the subunit stoichiometry of the complex, recombinant polypeptide chain fragments containing the heteromerization site were produced by heterologous gene expression in Escherichia coli. When mixed in equimolar amounts, these peptides preferentially formed parallel coiled-coil heterodimers under physiological buffer conditions. This demonstrates that the short C-terminal regions are sufficient to determine the specificity of interaction between GABAB receptor subunits. In contrast, isolated GABAB-R1 peptides folded into relatively unstable homodimers, whereas GABAB-R2 peptides were largely unstructured. Together with the data reported in the literature, the results presented here indicate that the functional GABAB receptor is a heterodimer assembled by parallel coiled-coil alpha-helices. 相似文献
113.
Pedigree analysis of HDL cholesterol concentration in baboons on two diets. 总被引:3,自引:3,他引:0
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J W MacCluer C M Kammerer J Blangero B Dyke G E Mott J L VandeBerg H C McGill Jr 《American journal of human genetics》1988,43(4):401-413
Using complex segregation analysis, we examined the effects of genetic factors and diet on serum concentrations of high-density-lipoprotein cholesterol (HDL-C) in baboons. In analyses of 710 baboons in 23 sire families, we found evidence for a major gene as well as a polygenic contribution to HDL-C concentration in baboons fed a basal (chow) diet and also in the same animals after challenge with a high-cholesterol, saturated-fat diet. There was evidence for a polygenic contribution to the change in HDL-C concentration in response to the dietary challenge, but there was no evidence for a major gene effect. 相似文献
114.
R Simões WB Feitosa CM Mendes AC Nicacio FRO de Barros 《Biotechnic & histochemistry》2013,88(3):79-83
Sperm chromatin integrity is essential for accurate transmission of male genetic information, and normal sperm chromatin structure is important for fertilization. Protamine is a nuclear protein that plays a key role in sperm DNA integrity, because it is responsible for sperm DNA stability and packing until the paternal genome is delivered into the oocyte during fertilization. Our aim was to investigate protamine deficiency in sperm cells of Bos indicus bulls (Nelore) using chromomycin A3 (CMA3) staining. Frozen semen from 14 bulls were thawed, then fixed in Carnoy's solution. Smears were prepared and analyzed by microscopy. As a positive control of CMA3 staining, sperm from one bull was subjected to deprotamination of nuclei. The percentage of CMA3-positive bovine sperm did not vary among batches. Only two bulls showed a higher percentage of CMA3-positive sperm cells compared to the others. CMA3 is a simple and useful tool for detecting sperm protamine deficiency in bulls. 相似文献
115.
We combined routinely reported tuberculosis (TB) patient characteristics with genotyping data and measures of geospatial concentration to predict which small clusters (i.e., consisting of only3 TB patients) in the United States were most likely to become outbreaks of at least 6 TB cases. Of 146 clusters analyzed, 16 (11.0%) grew into outbreaks. Clusters most likely to become outbreaks were those in which at least 1 of the first 3 patients reported homelessness or excess alcohol or illicit drug use or was incarcerated at the time of TB diagnosis and in which the cluster grew rapidly (i.e., the third case was diagnosed within 5.3 months of the first case). Of 17 clusters with these characteristics and therefore considered high risk, 9 (53%) became outbreaks. This retrospective cohort analysis of clusters in the United States suggests that routinely reported data may identify small clusters that are likely to become outbreaks and which are therefore candidates for intensified contact investigations. 相似文献
116.
Carsten Jaeger Verena Tellström Gabriela Zurek Sabine König Stefan Eimer Bernd Kammerer 《Metabolomics : Official journal of the Metabolomic Society》2014,10(5):859-876
Lifespan mutants of the nematode Caenorhabditis elegans are a much studied aging model, however, aging-related changes at the metabolome level remain largely unexplored. To identify metabolic features connected to mitochondrial dysfunction, a hallmark of aging and age-related disease, we analyzed a short-lived mitochondrial mutant (mev-1(kn1)), a long-lived mutant with enhanced cellular maintenance (ife-2(ok306)) and the novel double mutant ife-2(ok306);mev-1(kn1) which is normal-lived, possibly through attenuation of the metabolic mev-1 phenotype. Metabolomic analysis involved coupled gas chromatography–mass spectrometry with electron ionization (GC–EI–MS) and, in addition, recently introduced GC with soft atmospheric pressure chemical ionization coupled to time-of-flight mass spectrometry (GC–APCI–TOF–MS) to yield complementary mass spectrometric information for enhanced metabolite annotation. Multivariate analysis allowed distinction of mev-1 and ife-2 mutants from the wild type, while suggesting still another, distinct metabolic phenotype for the ife-2;mev-1 double mutant. In mev-1(kn1), disturbed energy metabolism was indicated by upset TCA cycle homeostasis, elevated glycolytic substrate and lactic acid levels as well as depletion of free amino acids pools. Surprisingly, these mitochondrially related changes were retained in the ife-2;mev-1 mutant, as were highly elevated levels of the dipeptide glycylproline indicative of increased collagen catabolism. However, the double mutant reverted mev-1(kn1) changes in uric acid and long-chain fatty alcohol metabolism, two pathways connected to the peroxisomal compartment. Our results are in line with recent evidence for a critical role of this organelle in aging and demonstrate the usefulness of non-targeted metabolomics approaches for detecting complex metabolic changes in the study of mitochondrial dysfunction. 相似文献
117.
Carolina V Morgante Patricia M Guimarães Andressa CQ Martins Ana CG Araújo Soraya CM Leal-Bertioli David J Bertioli Ana CM Brasileiro 《BMC research notes》2011,4(1):1-11
Background
Molecular genetic studies on rare tumour entities, such as bone tumours, often require the use of decalcified, formalin-fixed, paraffin-embedded tissue (dFFPE) samples. Regardless of which decalcification procedure is used, this introduces a vast breakdown of DNA that precludes the possibility of further molecular genetic testing. We set out to establish a robust protocol that would overcome these intrinsic hurdles for bone tumour research.Findings
The goal of our study was to establish a protocol, using a modified DNA isolation procedure and quality controls, to select decalcified samples suitable for array-CGH testing. Archival paraffin blocks were obtained from 9 different pathology departments throughout Europe, using different fixation, embedding and decalcification procedures, in order to preclude a bias for certain lab protocols. Isolated DNA samples were subjected to direct chemical labelling and enzymatic labelling systems and were hybridised on a high resolution oligonucleotide chip containing 44,000 reporter elements. Genomic alterations (gains and losses) were readily detected in most of the samples analysed. For example, both homozygous deletions of 0.6 Mb and high level of amplifications of 0.7 Mb were identified.Conclusions
We established a robust protocol for molecular genetic testing of dFFPE derived DNA, irrespective of fixation, decalcification or sample type used. This approach may greatly facilitate further genetic testing on rare tumour entities where archival decalcified, formalin fixed samples are the only source. 相似文献118.
119.
Crystallization conditions of an intact monoclonal IgG4 (immunoglobulin G, subclass 4) antibody were established in vapor diffusion mode by sparse matrix screening and subsequent optimization. The procedure was transferred to microbatch conditions and a phase diagram was built showing surprisingly low solubility of the antibody at equilibrium. With up-scaling to process scale in mind, purification efficiency of the crystallization step was investigated. Added model protein contaminants were excluded from the crystals to more than 95%. No measurable loss of Fc-binding activity was observed in the crystallized and redissolved antibody. Conditions could be adapted to crystallize the antibody directly from concentrated and diafiltrated cell culture supernatant, showing purification efficiency similar to that of Protein A chromatography. We conclude that crystallization has the potential to be included in downstream processing as a low-cost purification or formulation step. 相似文献
120.