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Intercostal muscle action inferred from finite-element analysis   总被引:2,自引:0,他引:2  
The external and internal intercostal muscles are important respiratory muscles in humans, but their mechanical actions have been controversial. We used finite-element analysis based on anatomic and mechanical measurements in dogs to assess the action of the intercostal and other rib cage muscles in a model of an isolated canine rib cage. When intercostal muscle forces of either the internal or the external layer were applied in a single interspace, they pulled the adjacent ribs together, consistent with published observations in dogs. However, when the forces were applied in all interspaces, the external layer caused an inspiratory motion and the internal layer caused an expiratory motion, consistent with conventional understanding of intercostal muscle actions. Parasternal intercostal, levator costae, and transversus thoracis (triangularis sterni) muscle actions were also simulated. These muscles caused expected movements of the ribs and sternum. We conclude that the actions of intercostal muscles depend on the spatial extent of their activation. Their actions in a single interspace and in multiple interspaces can be observed and explained with three-dimensional finite-element models.  相似文献   

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This review covers data on composition and structure of lipid A, core, and O-polysaccharide of the known lipopolysaccharides from Gram-negative bacteria. The relationship between the structure and biological activity of lipid A is discussed. The data on roles of core and O-polysaccharide in biological activities of lipopolysaccharides are presented. The structural homology of some oligosaccharide sequences of lipopolysaccharides to gangliosides of human cell membranes is considered.  相似文献   

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山东米口袋属植物的核型分析   总被引:3,自引:0,他引:3  
杨德奎 《广西植物》2002,22(4):349-351,T003
对山东米口袋属 ( Gueldenstaedtia Fisch.)植物进行了核型分析。米口袋 ( G.multiflora Bge.)核型公式 K( 2 n) =2 x=14 =14 m ,相对长度组成 2 n=14 =6 M2 +8M1,“1A”类型 ;狭叶米口袋 ( G.stenophylla Bge.)核型公式 K( 2 n) =2 x=14 =14 m,相对长度组成 2 n=14 =8M2 +6 M1,“1A”类型 ;光滑米口袋 ( G.maritimaMaxim.)核型公式 K( 2 n) =2 x=14 =12 m+2 sm,相对长度组成 2 n=14 =4 M2 +10 M1,“1A”类型。  相似文献   

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The efficiency of carbon and energy flows throughout metabolism defines the potential for growth and reproductive success of plants. Understanding the basis for metabolic efficiency requires relevant definitions of efficiency as well as measurements of biochemical functions through metabolism. Here insights into the basis of efficiency provided by (13)C-based metabolic flux analysis (MFA) as well as the uses and limitations of efficiency in predictive flux balance analysis (FBA) are highlighted. (13)C-MFA studies have revealed unusual features of central metabolism in developing green seeds for the efficient use of light to conserve carbon and identified metabolic inefficiencies in plant metabolism due to dissipation of ATP by substrate cycling. Constraints-based FBA has used efficiency to guide the prediction of the growth and actual internal flux distribution of plant systems. Comparisons in a few cases have been made between flux maps measured by (13)C-based MFA and those predicted by FBA assuming one or more maximal efficiency parameters. These studies suggest that developing plant seeds and photoautotrophic microorganisms may indeed have patterns of metabolic flux that maximize efficiency. MFA and FBA are synergistic toolsets for uncovering and explaining the metabolic basis of efficiencies and inefficiencies in plant systems.  相似文献   

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The protocol described in this report provides a simple, accurate and efficient assay for detection of transgenes and mutations in large colonies of rodents, using crude lysates prepared from the digit cut from the animals for identification purposes. This can be done as early as 6 days of age, minimizing trauma to the mice and allowing assays to be completed long before weaning. Editor's note: The US Food and Drug Administration (FDA) had amended its regulations on good laboratory practice (GLP) for nonclinical laboratory studies regarding humane procedures for animal identification and expreimentation (Vol. 54 # 75). While discouraging use of toe clipping for animal identification, the FDA charged each facility's Institutional Animal Care and Use Committee (IACUC) with the responsibility for evaluation and final approval. C.A.P.  相似文献   

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Mitochondria play essential roles in cell physiological processes including energy production, metabolism, ion homeostasis, cell growth, aging and apoptosis. Proteomic strategies have been applied to the study of mitochondria since 1998; these studies have yielded decisive information about the diverse physiological functions of the organelle. As an ideal model biological system, the nematode Caenorhabditis elegans has been widely used in the study of several diseases, such as metabolic diseases and cancer. However, the mitochondrial proteome of C. elegans remains elusive. In this study, we purified mitochondria from C. elegans and performed a comprehensive proteomic analysis using the shotgun proteomic approach. A total of 1117 proteins have been identified with at least two unique peptides. Their physicochemical and functional characteristics, subcellular locations, related biological processes, and associations with human diseases, especially Parkinson's disease, are discussed. An orthology comparison was also performed between C. elegans and four other model organisms for a general depiction of the conservation of mitochondrial proteins during evolution. This study will provide new clues for understanding the role of mitochondria in the physiological and pathological processes of C. elegans.  相似文献   

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利用生物信息学方法,对GeneBank中截至2006年9月收录的全部来源于山羊基因的共计637条表达序列标签(EST)进行了综合及分类分析。结果显示,在来源于绒山羊含毛囊皮肤的392条EST序列中有48条为编码角蛋白或角蛋白关联蛋白的基因;在乳腺来源的245条EST中则无此类基因,而是如免疫球蛋白基因、维生素转运蛋白基因、MHC等诸多种类基因,以免疫和酶类居多。两类不同组织来源的FST相应基因相似之处最显著的是编码核糖体蛋白的基因,其中含毛囊皮肤组织的EST中有15.1%,乳腺组织为21.6%,并且有两种不同组织来源的EST组成的26条基序(contigs)中,编码核糖体蛋白的有17条,高达65.4%。  相似文献   

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In this study the lipids of Borrelia burgdorferi, the causative agent of Lyme disease, were analyzed. Lipids comprise about 25-30% of the cell dry weight. The lipid fraction could be separated by HPTLC into 11 components. Staining of these components revealed two glycolipids and two phospholipids. The glycolipids represented about 50% of the total lipids and comprised only galactose as monosaccharide constituents. By means of mass spectrometric and gas chromatographic analysis both glycolipids could be identified as alpha-galactosyl-diacylglycerolipids with different fatty acid compositions. The phospholipids were identified as phosphatidylcholine and phosphatidylglycerol. Immunoassays with sera from patients with Lyme disease showed antibody reactivity only to the glycolipids, which was present in all stages of the disease. Other lipid components seemed to be non-immunogenic in Lyme disease. The glycolipids of B. burgdorferi may be, thus, considered promising candidates for diagnosis and possibly also for vaccination.  相似文献   

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Tooth microwear studies have been carried out for several reasons in the last decade. Most effort has been put into categorizing wear types that reflect dietary preferences in order to reconstruct the diet of extinct species. Several studies have shown that, for primates, carnivores and ruminants, it is possible to differentiate statistically the microwear associated with the major dietary adaptations in the group. It has further been found that more subtle dietary changes, such as seasonal ones, can be picked up if the sampling is good enough. It is important to recognize that, although it may be a valuable and legitimate concern to study the specific causes of different microwear patterns, that information is not essential for dietary reconstruction, if different microwear states can be shown empirically to correspond to different dietary regimes. Image enhancement and optical diffraction methods offer hope of automated scanning of large samples. This will be a major benefit as the methods currently in use are labor-intensive and time-consuming. Finally, it is urged that as many methods as possible be used to solve problems of dietary reconstruction.  相似文献   

15.
Phosphoprotein analysis: from proteins to proteomes   总被引:1,自引:0,他引:1  
Characterization of protein modification by phosphorylation is one of the major tasks that have to be accomplished in the post-genomic era. Phosphorylation is a key reversible modification occurring mainly on serine, threonine and tyrosine residues that can regulate enzymatic activity, subcellular localization, complex formation and degradation of proteins. The understanding of the regulatory role played by phosphorylation begins with the discovery and identification of phosphoproteins and then by determining how, where and when these phosphorylation events take place. Because phosphorylation is a dynamic process difficult to quantify, we must at first acquire an inventory of phosphoproteins and characterize their phosphorylation sites. Several experimental strategies can be used to explore the phosphorylation status of proteins from individual moieties to phosphoproteomes. In this review, we will examine and catalogue how proteomics techniques can be used to answer specific questions related to protein phosphorylation. Hence, we will discuss the different methods for enrichment of phospho-proteins and -peptides, and then the various technologies for their identification, quantitation and validation.  相似文献   

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The aim of our investigations was the microbiological analysis together with the evaluation of sensitivity of bacteria frequently isolated from blood cultures. Blood samples were taken from patients with symptoms suggesting bacteremia in Rydygier's Hospital in Cracow. A total of 11,170 blood samples taken from 1997 to 2000 were tested. Automatic VITAL system (bioMerieux) was applied to culture and detect microorganisms. Bacteria were identified by ATB system (bioMerieux). Susceptibility was detected by ATB and disc diffusion method. Percentage of positive results relating to detection of microorganisms of clinical significance was 16.9% (1891 cultures). Staphylococcus spp. (Staph. epidermidis in range 22.8% to 21.9%), Enterococcus spp. and Streptococcus spp. were most frequently isolated species among aerobic Gram-positive bacteria. In 2000, compared to 1997 the number of isolates of MRSA increased considerably (from 1.8% to 6.8%). In blood infections the increase of frequency of E. coli bacteria was also noted: 6.1% and 11.4% in 1997 and 2000, respectively. Among non-fermentant bacilli the percentage of occurrence of P. aeruginosa in the period of 4 years was comparable in the range 7.3% in 1997 to 7.2% in 2000. The increase in the frequency of blood infections of A. baumanii was also noticed (respectively from 4.8% to 9.9%). Susceptibility of P. aeruginosa strains to selected beta-lactame antibiotics and aminoglycosydes increased in 2000 in comparison to 1999. A. baumanii strains were 100% sensitive only to imipenem.  相似文献   

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安徽黄精属(Polygonatum)植物的分支分析   总被引:8,自引:1,他引:7  
周守标  张小平  张定成  邵建章   《广西植物》2000,20(4):329-331
以形态学为依据 ,结合细胞分类学、叶表皮和花粉形态的研究成果 ,用分支分析的方法探讨了安徽产黄精属 11种植物的种间演化关系。在分支分析中 ,选择万寿竹属、舞鹤草属和竹根七属作为复合外类群。根据复合外类群比较原则和一般演化规律 ,确定性状极性。结果表明 :( 1)琅琊黄精与长苞黄精为姊妹群 ,并与其余 9种黄精明显分为 2大支 ;( 2 )另一支 9种黄精中 ,玉竹、长梗黄精和金塞黄精亲缘关系密切并与其余 6种再分为 2支 ;( 3)剩下 6种黄精中 ,距药黄精和多花黄精 2种互生叶黄精极为密切并与 4种轮生叶黄精分为 2组 ;( 4 ) 4种轮生叶黄精中 ,黄精、轮叶黄精和安徽黄精亲缘关系最为密切  相似文献   

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One of the major complicating factors in insulin-dependent diabetes mellitus is nephropathy. Several investigators have linked heparan sulfate (HS) alterations in the glomerular basement membrane (GBM) with albuminuria as a marker of abnormal blood filtration and the subsequent progression to renal failure. In this study, we examined the fine structure of HS in the glomerulus and the GBM isolated from the kidneys of rats injected with streptozotocin. Using fluorophore-assisted carbohydrate electrophoresis, we obtained disaccharide composition analyses for HS. In a time course study, we observed that normal rat HS isolated from the GBM becomes more N-sulfated as the glomeruli mature over a period of 8 weeks. Diabetic rats injected with streptozotocin at the beginning of this period showed a reversal of this trend. Using a graded sieve technique, we found that two different sizes of glomeruli could be isolated from the rat kidneys and that there was a significant difference in the HS disaccharide content between these two pools of glomeruli. Only the larger sized glomeruli had less N-sulfation of HS as a result of insulin-dependent diabetes mellitus. This change in the fine structure of HS was localized to the GBM and was not associated with cell surface HS. We also generated oligosaccharides of HS that portray fine structural alterations in the diabetic rats indicative of a loss of the sulfation of N-acetylglucosamine.  相似文献   

19.
Quijano  Jairo  Arango  Gabriel J. 《Economic botany》1979,33(2):199-202
Economic Botany - A detailed chemical analysis of the breadfruit (Artocarpus altilis) is presented, followed by an analysis of the fat and a partial amino acid analysis of the globular proteins and...  相似文献   

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Microscopic analysis of 82 royal jelly samples obtained from several locations in Greece was carried out in order to study the pollen spectrum of Greek royal jelly. The analysis recorded over 60 taxa. The abundance of each pollen type varied among the areas and the samples. The most frequent pollen types found in the samples were Brassicaceae, Olea europaea, Eucalyptus, Trifolium, Rubus, Carduus-type, Hypericum, Daucus-type and Cistus. The majority of the pollen types found in the royal jelly samples were also found at the pollen flora around the apiaries.  相似文献   

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