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1.
This paper examines the usefulness of volume and area assessments of the sella turcica from radiographs in order to aid in the differential diagnosis of iron deficiency anemia in past populations. Lateral and posterior-anterior radiographs were taken of each cranium in the sample. The length, depth, and width of the sella turcica were then measured directly from the appropriate view, and subsequently the volume and area were calculated for each. The 20-25 year-old cohort was found to yield the most promising results; however, a statistical difference was not found to exist using the volume or area. The width dimension was found to be of far more use than any other in this study. In no instance was any feature of typical porotic hyperostosis, visually or radiographically, found to be statistically correlated with any difference in the dimensions of the sella turcica. A discussion of how the various dimensions of the sella turcica react to changes in size of the hypophysis cerebri is presented.  相似文献   

2.
The skeleton of an adult female exhibiting evidence of treponemal infection was recently recovered from the Hardin site in the piedmont region of North Carolina. Archaeological indicators suggest a late prehistoric affiliation. The skeleton is affected by a diffuse process resulting in surface changes, both destructive and appositional, node formation and shaft expansion, medullary encroachment and filling, cortical thickening, and fracture. There is both cranial and postcranial involvement. While treponemal infection is indicated, the atypical nature of the total pattern raises the possibility of multiple pathological processes operating simultaneously. The significance of this case is threefold. It provides information on the ability of prehistoric peoples to cope with disease. It reminds the paleopathologist of the dangers inherent in attempts at singular and specific diagnoses. It sheds new light on the epidemiology of the treponemal diseases.  相似文献   

3.
Summary We have reported preparations and gas chromatographic analyses of volatile derivatives of sulfuric acid and taurine (Masuoka et al., 1988; 1989). By extending these studies, we have developed a method for the gas chromatographic determination of cysteic acid. Cysteic acid was converted to the N-isobutoxycarbonyl derivative by the reaction with isobutyl chloroformate in the presence of sodium hydroxide. After desalting with a cation-exchange column, the derivative was converted to the silver salt by reacting with silver oxide. The resulting silver salt was quantitatively esterified with methyl iodide in the presence of dimethyl sulfate and silver oxide. Dimethyl N-isobutoxy-carbonylcysteate [methyl 2-(N-isobutoxycarbonylamino)-3-(methoxysulfonyl) propanoate] formed was analyzed by gas chromatography. The calibration curve was linear up to 5.0µmol per ml of cysteic acid and the recovery was more than 95%.  相似文献   

4.
l-canavanine, the toxic guanidinooxy analogue of l-arginine, is the product of plant secondary metabolism. The need for a detoxifying mechanism for the producer plant is self-evident but the larvae of the bruchid beetle Caryedes brasiliensis, that is itself a non-producer, have specialized in feeding on the l-canavanine-containing seeds of Dioclea megacarpa. The evolution of a seed predator that can imitate the enzymatic abilities of the host permits us to address the question of whether the same problem of amino acid recognition in two different kingdoms has been solved by the same mechanism. A discriminating arginyl-tRNA synthetase, detected in a crude C. brasiliensis larval extract, was proposed to be responsible for insect's ability to survive the diet of l-canavanine (Rosenthal, G. A., Dahlman, D. L., and Janzen, D. H. (1976) A novel means for dealing with L-canavanine, a toxic metabolite. Science 192, 256258). Since the arginyl-tRNA synthetase of at least three genetic compartments (insect cytoplasmic, insect mitochondrial and insect gut microflora) may participate in conferring l-canavanine resistance, we investigated whether the nuclear-encoded C. brasiliensis mitochondrial arginyl-tRNA synthetase plays a role in this discrimination. Steady state kinetics of the cloned, recombinant enzyme have revealed and quantified an amino acid discriminating potential of the mitochondrial enzyme that is sufficient to account for the overall l-canavanine misincorporation rate observed in vivo. As in the cytoplasmic enzyme of the l-canavanine producer plant, the mitochondrial arginyl-tRNA synthetases from a specialist seed predator relies on a kinetic discrimination that prevents l-canavanine misincorporation into proteins.  相似文献   

5.
Excavations during 1974 at the Peruvian Preceramic site of Alto Salaverry led to the discovery of a child's skeleton. The fragmentary skeleton exhibits cribra orbitalia, a pitting of the orbital roof associated with anemia. This specimen provides the first evidence of anemia in a population of the predominantly non-agricultural Peruvian Preceramic and extends the antiquity of the pathology among Precolumbian Peruvians.  相似文献   

6.
Amino acid composition and the evolutionary rates of protein-coding genes   总被引:14,自引:0,他引:14  
Summary Based on the rates of amino acid substitution for 60 mammalian genes of 50 codons or more, it is shown that the rate of amino acid substitution of a protein is correlated with its amino acid composition. In particular, the content of glycine residues is negatively correlated with the rate of amino acid substitution, and this content alone explains about 38% of the total variation in amino acid substitution rates among different protein families. The propensity of a polypeptide to evolve fast or slowly may be predicted from an index or indices of protein mutability directly derivable from the amino acid composition. The propensity of an amino acid to remain conserved during evolutionary times depends not so much on its being features prominently in active sites, but on its stability index, defined as the mean chemical distance [R. Grantham (1974) Science 185862–864] between the amino acid and its mutational derivatives produced by single-nucleotide substitutions. Functional constraints related to active and binding sites of proteins play only a minor role in determining the overall rate of amino acid substitution. The importance of amino acid composition in determining rates of substitution is illustrated with examples involving cytochrome c, cytochrome b5,ras-related genes, the calmodulin protein family, and fibrinopeptides.  相似文献   

7.
丛宁  袁莉民 《生物技术》1994,4(2):18-20
适量磁场辐照水生动物的促生长机理是一复杂的研究课题,本文从营养学、生物化学角度对该课题做了阶段性的初浅分析。我们发现适量的磁场辐照在美国青蛙蝌蚪期肌蛋白氨基酸方面的效应是有益的,它不会引起氨基酸组份的改变,而且能使氨基酸含量增加30%以上。  相似文献   

8.
The nonessential amino acids are involved in a large number of functions that are not directly associated with protein synthesis. Recent studies using a combination of transorgan balance and stable isotopic tracers have demonstrated that a substantial portion of the extra‐splanchnic flux of glutamate, glutamine, glycine and cysteine derives from tissue synthesis. A key amino acid in this respect is glutamic acid. Little glutamic acid of dietary origin escapes metabolism in the small intestinal mucosa. Furthermore, because glutamic acid is the only amino acid that can be synthesized by mammals by reductive amination of a ketoacid, it is the ultimate nitrogen donor for the synthesis of other nonessential amino acids. Because the synthesis of glutamic acid and its product glutamine involve the expenditure of adenosine triphosphate (ATP), it seems possible that nonessential amino acid synthesis might have a significant bearing on the energetics of protein synthesis and, hence, of protein deposition. This paper discusses the topic of the energy cost of protein deposition, considers the metabolic physiology of amino acid oxidation and nonessential amino acid synthesis, and attempts to combine the information to speculate on the overall impact of amino acid metabolism on the energy exchanges of animals.  相似文献   

9.
A semi-automated method for amino acid derivatization and analysis has been validated for use in analysis of protein biopharmaceuticals. The method includes protein hydrolysis, o-phthalaldehyde derivatization, and reversed-phase high-performance liquid chromatography analysis in a general-purpose UV-visible high-performance liquid chromatography system. Amino-acid derivatization is performed automatically by the high-performance liquid chromatography autosampler right before injection. The required validation parameters, i.e., specificity, linearity, accuracy, precision, limit of detection, and limit of quantification, were studied for bovine serum albumin and for a recombinant human Fab fragment. The method can be employed as an absolute quantification method for determination of extinction coefficients of recombinant proteins.  相似文献   

10.
The amino acid composition of Nephila clavipes dragline silk fiber was determined by conducting 1H nuclear magnetic resonance (NMR) spectroscopy experiments on acid-hydrolyzed material. N. clavipes dragline silk was found to consist of 43.0 ± 0.6% Gly, 29.3 ± 0.2% Ala, 9.1 ± 0.1% Glx, 4.0 ± 0.1% Leu, 3.3 ± 0.1% Tyr, 3.4 ± 0.2% Ser, 2.7 ± 0.1% Pro, 2.1 ± 0.1% Arg, 1.07 ± 0.05% Asx, 0.96 ± 0.05% Val, 0.48 ± 0.03% Thr, 0.35 ± 0.03% Phe, and 0.28 ± 0.03% Ile. Compared with standard chromatography-based amino acid analysis (AAA), the chemical resolution of NMR allows for an amino acid solution to be characterized without separation and is shown to provide considerably higher precision. This allows for more accurate statistics on the variability of amino acids in spider dragline silk. In general, this 1H NMR AAA technique is applicable to a large range of proteins and peptides for precise composition characterization, especially when the precise content of a minor component is critical and relatively large amounts of sample are available (microgram to milligram quantities).  相似文献   

11.
墨龙系列酒中氨基酸组分评价   总被引:1,自引:0,他引:1  
采用岛津L_(c-bA)高效液相色谱仪测定墨龙醇、麒麟玉液、猕猴桃乳酒中13种氨基酸总量分别为508.2、491.7、247.4mg/100ml,其中12种人体必需、半必需氨基酸与10种药效氨基酸的含量和分别占总含量的59.7%、65.5%、76.2%和43.8%、48.1%、47.5%。  相似文献   

12.
Rabbit mammary fatty acid synthase was labelled in the acyl transferase domain(s) by the formation of the O-ester intermediates after incubation with [14C]acetyl- or malonyl-CoA. Elastase peptides containing the labelled acyl groups were isolated using high performance liquid chromatography and sequenced by fast atom bombardment mass spectrometry. An identical peptide (acyl-Ser---Leu---Gly---Glu---Val---Ala) was obtained after labelling with acetyl- or malonyl-CoA. This confirms the hypothesis that, unlike Escherichia coli or yeast, a single transferase catalyses the transfer of both acetyl- and malonyl-groups in the mammalian complex. The sequence at this site is compared with that around the active serine in other acyl transferases and hydrolases.  相似文献   

13.
Summary Six of the seven chain isomers of six-carbon acyclic primary-amino alkanoic acids (leucine isomers) have been either identified or confirmed in hot-water extracts of the Murchison meteorite using combined gas chromatography-mass spectrometry (GC-MS) and ion exchange chromatography. 2-Amino-2-ethylbutyric acid, 2-amino-2,3-dimethylbutyric acid, pseudoleucine, and 2-methylnorvaline were positively identified by GC-MS. These amino acids have not been previously reported to occur in natural materials and may be uniquely meteoritic in origin. The presence of leucine and isoleucine (including the diastereoisomer, alloisoleucine) was confirmed. Peaks corresponding to norleucine were seen by ion-exchange and gas chromatography but characteristic mass spectra were not obtained. The-branched chain isomers in this series are quantitatively the most significant. These results are compared with literature data on amino acid synthesis by electrical discharge and Fischer-Tropsch-type catalysis. Neither model system produces an amino acid suite that is completely comparable to that found in the Murchison meteorite.Contribution 113 from the Center for Meteorite Studies  相似文献   

14.
Abstract The incorporation of a very low concentration (0.015 μM) of an [3H]amino acid mixture was measured for a natural population of Oscillatoria rubescens DC in samples from a eutrophic lake, Lake Nantua (France).
The kinetics of amino acid incorporation in the size fraction ⩾12 μ m showed that uptake was fast and that the maximum was reached after 4 h.
Microautoradiography demonstrated that Oscillatoria rubescens is able to utilize for protein synthesis an external pool of amino acids whose [3H] label becomes distributed generally throughout the cell.  相似文献   

15.
Summary Humic acids from four Brazilian topsoils of different origins and four soil fungal melanins, synthesized under two cultural conditions, were subjected to 6N HCl hydrolysis and their amino acid distribution patterns qualitatively and quantitatively determined. Both soil and fungal polymers showed similar patterns with aspartic acid, glutamic acid, glycine and alanine as the dominant amino acids. Some variations noted were more quantitative than qualitative, the similarities were more pronounced than differences, indicating that the fungal melanins may play a significant role in the formation of soil humic acid polymers. The humic acids of Brazilian soils had amino acid distribution patterns similar to those reported for humic acids of other tropical and temperate soils.  相似文献   

16.
Summary Based on population genetics theory of the evolution of multigene families, the sequence variability of the variable regions of immunoglobulins compiled by Kabat et al. (1976) has been analysed. An amino acid identity coefficient either within or between species is calculated separately for both the hypervariable and the framework regions. Under the somatic mutation hypothesis, the somatic component of amino acid diversity is in addition to the germ line component and should contribute an amount of change between the hypervariable and framework regions that is independent of the time since the divergence of any two immunoglobulin gene families. The relationship between the identity coefficient of the hypervariable region and that of the framework region is shown to be not in accord with such prediction. The result indicates that the rate of evolutionary accumulation of amino acid replacements in the hypervariable region is roughly three times more rapid than in the framework region and the hypervariability within a species is a necessary consequence of the high evolutionary rate.Contribution no. 1271 from the National Institute of Genetics, Mishima 411, Japan  相似文献   

17.
BackgroundIron deficiency anemia (IDA) is the most common type of anemia worldwide and has many adverse effects on life quality. This meta-analysis study aims to show that reticulocyte hemoglobin content (CHr) is more effective than routinely used parameters in the diagnosis of IDA.MethodsComprehensive and systematic research was done using international databases including PubMed, Web of Science, Cochrane Library, Science Direct, and Google Scholar, which contain all articles published on IDA until December 29, 2020. Seventeen articles were included in the meta-analysis.ResultsThe analyses found the Cohen''s deffect size (Standardized Mean Difference) values of the parameters. Accordingly, CHr is 2.84 (95% CI 2.36 to 3.31), mean corpus volume (MCV) is 2.46 (95% CI 1.97 to 2.95), ferritin is 2.37 (95% CI 1.63 to 3.11), and transferrin saturation (TSAT) is 3.76 (95% CI 2.14 to 5.38). To diagnose IDA, the sensitivity value of the CHr concentration was found as 83.5% (95% CI 76.1 to 89.8), specificity value to be 91.8% (95% CI 85.5 to 96.4), and mean cut-off value as 28.2 pg.ConclusionsThe results of our study reveal the findings that CHr is a better biomarker than MCV and ferritin used in determining IDA, and its efficacy is lower than TSAT. It is very important to use it routinely for the pre-diagnosis of IDA, which is very important for public health. The groups in the study are heterogeneous but contain bias. Therefore, meta-analyses of studies with less heterogeneity of CHr are needed.  相似文献   

18.
Abstract The NADP-linked glutamate dehydrogenase (NADP-GDH) from epimastigotes of Trypanosoma cruzi , Tul 2 stock, has been purified by an improved procedure. The enzyme has subunit molecular weight (47 kDa), amino acid composition and N-terminal sequence similar to those of the NADP-GDH from Escherichia coli , including the N-terminal extension of 15 amino acids present in the E. coli enzyme, but not in the NADP-GDH from Neurospora crassa .  相似文献   

19.
We determined the complete amino acid sequences of the Erabu sea snake (Laticaudia semifasciata) hemoglobin by analyzing the intact globin chains, enzymatically digested fragments, and chemical cleavage fragments to clarify the molecular evolution and phylogenetic classification of the sea snake. The Erabu sea snake has two types of hemoglobin components, Hb-I and Hb-II, which contain different alpha- and beta-chains. This is the second report of the complete primary structure for hemoglobin of snakes. The sequences were compared with those of other reptilian hemoglobins. Amino acids at positions critical for the structure and physiological functions of hemoglobin were loosely conserved. The requirements for binding of ATP and of diphosphoglycerate as allosteric effectors of beta-globins seemed to be fulfilled.  相似文献   

20.
采用正交试验方法,对鲜猪血加压水解制取复合氨基酸工艺条件进行优选。试验结果表明,采用鲜猪血加压水解制取复合氨基酸与采用猪血粉常压水解相比,简化了生产工序,缩短水解时间8~12小时,降低能耗2倍多,减少硫酸用量2~3倍,而产品质量稳定可靠。  相似文献   

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