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1.
Several disease loci have been mapped to the Xq21.3–Xq22 region of the human X Chromosome (Chr) including X-linked agammaglobulinemia (XLA), Fabry disease, Alport syndrome, and Pelizaeus Merzbacher disease. Upon cloning of the XLA gene, Bruton's tyrosine kinase (btk), both Fabry disease and XLA were mapped within the same 50- to 70-kb interval. In order to investigate the genomic organization of the region surrounding btk and the Fabry disease gene, -galactosidase A (gla), we constructed a 6-cosmid contig spanning the region from 5 of gla to 3 of btk. Two of these cosmids spanning most of the coding sequence and the upstream region of btk and gla, U237D10 and U230D1, were sequenced by a random shotgun strategy combined with automated sequencing, resulting in 69 kb of contiguous genomic sequence. Sequencing of U237D10 showed btk to be comprised of 19 exons spanning over 35 kb. Sequencing of U230D1 showed that the 3 end of gla is 9 kb from the 5 end of btk and also demonstrated the presence of two additional genes in the region immediately 5 to btk. The surprisingly high gene density is similar to that seen previously only in the human major histocompatibility locus.  相似文献   

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Hydrophilicity index is used to locate antigenic determinants on two related groups of proteins-myoglobin and hemoglobin. The data on 41 species (including 34 mammals) of myoglobin show that average hydrophilicity for the complete myoglobin molecules as well as the average hydrophilicity for all hydrophilic regions put together seem to remain constant; the variation in the size and location of the antigenic determinants in these species is very small indicating that the antigenic sites are not shifted during evolution. In the case of both the proteins there is a good agreement between the antigenic sites picked up by using hydrophilicity index and the experimentally determined antigenic sites. The data on 56 species of hemoglobin α-chains and 44 species of hemoglobinβ-chains showed that although there are few sites on hemoglobin which have remained invariant during evolution, there is a significant variation in other sites in terms of either a splitting of a site, or a drastic change in the hydrophilicity values and/or a length of the site. Comparison of the hydrophilicity data on these two groups of proteins suggests that hemoglobins which perform a variety of functions as compared to myoglobins are evolving faster than myoglobins supporting the contention of earlier workers.  相似文献   

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The membrane interaction and solution conformation of two mutants of the β-hairpin antimicrobial peptide, protegrin-1 (PG-1), are investigated to understand the structural determinants of antimicrobial potency. One mutant, [A6,8,13,15] PG-1, does not have the two disulfide bonds in wild-type PG-1, while the other, [Δ4,18 G10] PG-1, has only half the number of cationic residues. 31P solid-state NMR lineshapes of uniaxially aligned membranes indicate that the membrane disorder induced by the three peptides decreases in the order of PG-1>[Δ4,18 G10] PG-1?[A6,8,13,15] PG-1. Solution NMR studies of the two mutant peptides indicate that [Δ4,18 G10] PG-1 preserves the β-hairpin fold of the wild-type peptide while [A6,8,13,15] PG-1 adopts a random coil conformation. These NMR results correlate well with the known activities of these peptides. Thus, for this class of peptides, the presence of a β-hairpin fold is more essential than the number of cationic charges for antimicrobial activity. This study indicates that 31P NMR lineshapes of uniaxially aligned membranes are well correlated with antimicrobial activity, and can be used as a diagnostic tool to understand the peptide-lipid interactions of these antimicrobial peptides.  相似文献   

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Nir Eyal 《Bioethics》2020,34(9):941-947
The ethics of research on human subjects is often construed as a fine balance between the interests of patients in need of novel health interventions, and those of study participants who should remain safe in the process. But there is a third group in the mix. Some people belong to neither category, yet research can affect or jeopardize them. Call such people “bystanders.” This article shows that thinking about bystander protection can question whether there is an upper limit on the risks that studies may legitimately visit upon their participants. Thus, thinking about appropriate bystander protection can shed light on the appropriate protection of study participants. Core research ethics, which focuses on the latter, must consider the former as well.  相似文献   

7.
In this article, we present a new, easy-to-implement assay for methionine γ-lyase (MGL)-catalyzed γ-elimination reactions of l-methionine and its analogues that produce α-ketobutyrate (α-KB) as product. The assay employs ultraviolet–visible (UV–Vis) spectrophotometry to continuously monitor the rate of formation of α-KB by its absorbance at 315 nm. We also employ a nonlinear data analysis method that obviates the need for an “initial slope” determination, which can introduce errors when the progress curves are nonlinear. The spectrophotometric assay is validated through product analysis by 1H NMR (nuclear magnetic resonance), which showed that under the conditions of study l-methionine (l-met) and l-methionine sulfone (l-met sulfone) substrates were converted to α-KB product with greater than 99% yield. Using this assay method, we determined for the first time the Michaelis–Menten parameters for a recombinant form of MGL from Porphyromonas gingivalis, obtaining respective kcat and Km values of 328 ± 8 min−1 and 1.2 ± 0.1 mM for l-met γ-elimination and 2048 ± 59 min−1 and 38 ± 2 mM for l-met sulfone γ-elimination reactions. We envisage that this assay method will be useful for determining the activity of MGL γ-elimination reactions that produce α-KB as the end product.  相似文献   

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The addition of fiveFusarium species, cultured on wheat grain, to the standart chicken diet DKA starter, caused atrophic changes in the thymus and testes, as observed in the microscopic picture of these organs. The degree of lesions were depended on theFusarium species and its amount added to the standart diet.  相似文献   

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An immunohistochemical and immunoelectron microscopic study was used to demonstrate tyrosine hydroxylase (TH) and dopamine -hydroxylase (DBH) immunoreactivities in the rat pancreas. Small TH immunoreactive cells were found in close contact with large TH immunonegative ganglion cells among the exocrine glands and were occasionally found in some islets. Some of these TH immunoreactive cells were also DBH immunopositive. The immunoreaction product was seen diffusely in the cytoplasm and in the granule cores of TH immunoreactive cells. All intra-pancreatic ganglion cells were immunoreactive for DBH, but not for TH. The TH immunoreactive cells were identified as small intensely fluorescent (SIF) cells due to their localization and morphological characteristics and showed no insulin, glucagon, somatostatin or pancreatic polypeptide immunoreactivities. These results indicate that SIF cells may release dopamine or noradrenaline to adequate stimuli while the intra-pancreatic ganglion cells with only DBH may not synthesize catecholamines in a normal biosynthetic pathway. TH immunoreactive nerve bundles without varicosities and fibers with varicosities, associated or unassociated with blood vessels, were found in both the exocrine and endocrine pancreas. Close apposition of TH immunoreactive nerve fibers to the smooth muscle and endothelial cells of the blood vessels was observed. A close apposition between TH immunoreactive nerve fibers and exocrine acinar cells and islet endocrine cells was sometimes found in the pancreas. The immunoreaction product was seen diffusely in the axoplasm and in the granular vesicles of the immunoreactive nerve fibers. Since no TH immunoreactive ganglion cells were present in the rat pancreas, the present study suggests that noradrenergic nerve fibers in the pancreas may be extrinsic in origin, and may exert an effect on the regulation of blood flow and on the secretory acitivity of the acinar cells, duct cells and endocrine cells.  相似文献   

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Metal load is an abiotic stress that becomes stronger by continual industrial production, wastage, and long-range transport of contaminants. It deteriorates the conditions of agricultural soil that leads to lower growth of cereals as well as decreasing nutritional value of harvested grains. Cadmium (Cd) entry by food chain also affects the health of population. The present study is focused on finding out the superior cereal variety under increasing Cd regime. The plants were grown in increasing Cd levels (0–1000 µM) in the medium and were investigated on 15th day of the exposure. Various parameters like antioxidative enzymes and osmoprotectant levels were studied in both roots and shoots. Cd accumulation in plant organs was determined by atomic absorption spectrophotometry (AAS). Analysis of stress tolerance mechanisms through reactive oxygen species (ROS) scavenging and better partitioning of Cd in roots indicated kodo millet to be more stress tolerant than wheat.  相似文献   

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Phycobilins are an important group of pigments that through complementary chromatic adaptation optimize the light-harvesting process in phytoplankton cells, exhibiting great potential as cyanobacteria species biomarkers. In their extracted form, concentrations of these water-soluble molecules are not easily determined using the chromatographic methods well suited to solvent-soluble pigments. Insights regarding the quantitative spectroscopic analysis of extracted phycobilins also remain limited. Here, we present an in-depth study of two methods that utilize the spectral properties of phycobilins in aqueous extracts. The technical work was carried out using high-purity standards of phycocyanin, phycoerythrin, and allophycocyanin. Calibration parameters for the spectrofluorometer and spectrophotometer were established. This analysis indicated the possibility of detecting pigments in concentrations ranging from 0.001 to 10 μg cm?3. Fluorescence data revealed a reproducibility of 95 %. The differences in detection limits between the two methods enable the presence of phycobilins to be investigated and their amounts to be monitored from oligotrophic to eutrophic aquatic environments.  相似文献   

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Summary The crosslinking effects of formaldehyde, -hydroxyadipaldehyde and glutaraldehyde have been compared by various techniques. Using a micro-Ouchterlony technique with an aldehyde treated bovine serum albumin-rabbit anti-bovine serum albumin system it was found that glutaraldehyde prevented precipitin line formation except at very high titres of antibody. The effects of formaldehyde and -hydroxyadipaldehyde were less marked. Cellulose acetate electrophoresis of aldehyde treated bovine serum albumin showed an increase in mobility compared with the untreated protein. Starch gel electrophoresis of aldehyde fixed liver slices showed no protein loss after glutaraldehyde fixation whereas the other aldehydes permitted proteins to be extracted. Polyacrylamide gel electrophoresis of the aldehyde treated bovine serum albumin showed a little change in mobility after formaldehyde and -hydroxyadipaldehyde treatment and a little polymer formation. Glutaraldehyde on the other hand produced much polymer. These findings were confirmed by gel filtration with Sephadex G-200. Intermolecular crosslinking with glutaraldehyde was dependant on the aldehyde concentration.  相似文献   

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The present investigation primarily focussed on evaluating the efficacy of exogenous proline on the flower longevity of Dianthus chinensis L. Floral buds were harvested at the paint brush stage (i.e., a day prior to anthesis) and divided into 6 sets, with one set of buds (i.e., control) held in distilled water and rest of the 5 sets were supplemented with various concentrations of proline, viz., 10 mM, 20 mM, 30 mM, 40 mM and 50 mM. The application of proline at 40 mM concentration proved out to be most effective in improving the longevity of the flowers by about 4 days as compared to the control. The ameliorated longevity coincided with enhanced floral diameter, fresh mass, dry mass and water content. The flowers with delayed senescence also maintained higher soluble proteins, sugars and phenols. The results suggest that exogenous proline effectively alleviates oxidative stress in the petal tissue, as evident by a relatively lower maloendialdehyde content, which is manifested in the form of reduced lipid peroxidation (LPO). Reduced LPO was commensurate with increased membrane stability, quantified by membrane stability index. Moreover, the flowers with improved longevity exhibited a decline in lipoxygenase activity and significant augmentation of antioxidant enzymes superoxide dismutase, catalase and ascorbate peroxidase.  相似文献   

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Summary Proline and Pro-derived peptidomimetics, such as meoxPro-Oic (4-methoxy-proline-octahydro indolic acid), and DBF (2-aminoethyl-6-dibenzofuran propionic acid) were introduced into thymopentin-derived penta-[SP5-] and hexa-[SP6-] peptides and penta-, hexa- and hepta-alanine. Surprisingly, we found that cyclomonomer formation in the investigated penta- and hexapeptides was drastically hindered by the presence of proline regardless of position.  相似文献   

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The interaction between aluminium and cysteine and cystine was evaluated by means of ion-exchange experiments and potentiometry. Ion-exchange experiments included other ligands with affinity for aluminium and two kinds of resins, either a Na+-form or an Al3+-form exchanger. The ability of the ligands to keep aluminium in solution in the presence of the Na+ exchanger or to withdraw it from the Al3+-form resin was evaluated. Aluminium quantification was carried out by either graphite-furnace or flame atomic absorption spectrometry. Aluminium extraction isotherms were linearised using the Scatchard plot, and stability constants were obtained from the curves’ slopes. The experiments showed that the ability of the ligands to withdraw aluminium from the Al3+-form resin increased following the order cysteine < oxalate < citrate = cystine < nitrilotriacetic acid < ethylenediaminetetraacetic acid. Potentiometric titrations, carried out in aqueous solution with constant ionic strength and temperature, showed that the predominant species in solution have a metal–ligand proportion of 1:1 for both amino acids. The main species are Al(OH)3L, with log K of 6.2 for cysteine, and AlL and Al(OH)L, with log K of 10.3 and 1.7, respectively, for cystine. Stability constants obtained from the Scatchard plots showed a linear correlation with the stability constants obtained by potentiometry for cystine and cysteine in this work and those collected from the literature for the other ligands. These results show that cysteine and cystine extract and maintain aluminium in solution, which may explain elevated concentrations of aluminium in parenteral nutrition solutions containing these amino acids.Electronic Supplementary Material Supplementary material is available to authorised users in the online version of this article at .  相似文献   

20.
《Cancer epidemiology》2014,38(6):741-747
Background and aimsCurative treatment of hepatocellular carcinoma (HCC) is dependent on early diagnosis. Surveillance of patients at high risk for HCC is a key determinant to achieve this goal, but may be an underutilized tool. The aim of this study was to determine the rate of pre-diagnosis surveillance in patients with HCC in a large population-based cohort and to assess to what extent cirrhosis was known prior to the diagnosis of HCC.MethodsAll patients diagnosed with HCC during 2000–2009 in The South-Eastern Regional Health Authority, representing 56% of the Norwegian population, were identified from The National Cancer Registry and the medical records were reviewed.ResultsFifteen out of 486 patients (3%) were diagnosed by surveillance. Potential curative treatment was offered to 58% of the patients who underwent surveillance as opposed to 15% in the non-surveillance group. Only age ≤65 years was an independent predictor of screening in a multivariate model. Almost two thirds of the patients with cirrhosis were unrecognized prior to the HCC diagnosis. Two hundred and fourteen patients (44%) were non-cirrhotics.ConclusionRegular HCC surveillance in at-risk populations is virtually not applied in Norway and this may contribute to inferior overall survival. Failure to recognize cirrhosis and a high rate of HCC in non-cirrhotic patients will be limiting factors for the overall effectiveness of a potential surveillance program.  相似文献   

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