Vinculin is an essential component for normal myofibrillar arrangement in fetal mouse cardiac myocytes

Vinculin is a cytoskeletal protein that is believed to be an essential component in the linkage of cytoskeletal actin filaments to the plasma membrane. To investigate the precise function of vinculin in the development of cardiac myofibrils, antisense oligodeoxynucleotides complementary to vinculin mRNA were used to perturb the expression of the protein during myofibril assembly and arrangement in mouse cardiac myocytes. Fetal (day 18-20 post-conception) mouse cardiac myocytes were isolated by collagenase digestion, separated by Percoll density gradient centrifugation, and plated on aligned collagen gels. By 72 h of culture, mouse myocytes displayed an elongated in vivo-like phenotype in parallel with the aligned fibrils of the collagen gels with polarized arrays of myofibrils. Two different antisense oligonucleotides (20-mer) altered the formation of the tissue-like phenotype of myocytes. These antisense oligonucleotides suppressed vinculin protein expression at 43.5+/-26.8% and 48.7+/-20.9% when compared to myocytes that were not treated. Examination of these myocytes by confocal scanning laser and transmission electron microscopy revealed a disruption of the aligned in vivo-like phenotype, assembly of thick and thin filaments, and formulation of Z-bands. Random sequence 20-mer oligonucleotides used as controls had little detectable effect on vinculin protein expression (94.2+/-14.8%), cell shape, normal alignment or assembly of myofibrils. These results indicate that vinculin is a critical cytoskeletal component, that functions in the determination of cell shape and the arrangement and organization of developing myofibrils.     

Geranoyl-CoA carboxylase: a novel biotin-containing enzyme in plants

Geranoyl-CoA carboxylase (EC 6.4.1.4) is a biotin-containing enzyme previously described in two genera of bacteria. Here we report the presence of geranoyl-CoA carboxylase in kingdom Plantae. Geranoyl-CoA carboxylase was purified 180-fold from maize leaves. The enzyme has a biotin-containing subunit of 122 kDa. The pH optimum for activity is 8.3. The apparent Km values for the substrates geranoyl-CoA, bicarbonate, and ATP are 64 +/- 5 microM, 0. 58 +/- 0.04 mM, and 8.4 +/- 0.4 microM, respectively. Subcellular fractionations indicate that geranoyl-CoA carboxylase is located in plastids. Geranoyl-CoA carboxylase activity is ubiquitous in organs of monocots and dicots and varies with development. We postulate that geranoyl-CoA carboxylase plays an important role in isoprenoid catabolism in plants, in a pathway analogous to that shown in Psuedomonas sp. In plants, this catabolic pathway would require the interaction of at least three subcellular compartments (plastids, microbodies, and mitochondria) and two biotin-containing enzymes, geranoyl-CoA carboxylase and 3-methylcrotonyl-CoA carboxylase.     

Experimental hepatobiliary fascioliasis in rabbits: a radiology-pathology correlation

RATIONALE AND OBJECTIVES: The authors sought to correlate the radiologic findings of hepatobiliary fascioliasis with pathologic features. METHODS: Serial ultrasound, computed tomography (CT), and magnetic resonance findings in seven rabbits with experimentally induced fascioliasis were obtained every other week. Direct cholangiogram was also obtained after the rabbits were killed. Radiology-pathology correlation was done in specimens. RESULTS: In the parenchymal phase (an acute phase of parenchymal invasion of a larva), CT showed subcapsular clustered areas of low attenuation. Magnetic resonance appearance was similar in shape but better than CT in characterizing the hemorrhagic nature of the lesion. Ultrasound findings were nonspecific in this phase. In the ductal phase (a stationary phase after residing in the bile duct), CT showed dilatation of central ducts with symmetric periportal hypoattenuation (periportal tracking). Magnetic resonance could not depict mild ductal dilatation. Ultrasound was most valuable in demonstrating the moving worm within the dilated duct. Pathologically, the hepatic parenchymal lesions consisted of a cluster of eosinophilic granulomas with hemorrhagic change (migratory tract of the flukes). Ductal changes were observed predominantly in the central bile ducts. Periportal lymphangiectasia was also noted. CONCLUSIONS: Computed tomography or magnetic resonance can demonstrate the characteristic evolutionary pattern of fascioliasis that reflects the unique life cycle of Fasciola hepatica. The role of ultrasound, although limited in the parenchymal phase, was most useful in the ductal phase in that it demonstrated the moving worms themselves.     

Development of a sustainability reporting scheme for biofuels: A UK case study

In 2008, the UK launched the first regulatory sustainability reporting scheme for biofuels. The development of the scheme, managed by the Low Carbon Vehicle Partnership for the Department for Transport, involved extensive stakeholder engagement. The scheme has significantly increased understanding by policy-makers, the biofuels industry and its supply chains on how to monitor and manage the sustainability risks of biofuels and increase their greenhouse-gas benefits. It is providing a practical model for similar developments globally. To receive certificates in order to meet volume obligations under the Renewable Transport Fuel Obligation (RTFO), suppliers must provide a monthly carbon and sustainability report on individual batches of renewable fuels they supply into the UK. The Renewable Fuels Agency produces aggregate monthly reports of overall performance and quarterly updates of individual supplier performance. This scheme is an important first step to assist the biofuels industry to demonstrate its environmental credentials and justify the subsidies received. The paper provides a case study of the development of the scheme, its initial outcomes and outstanding challenges.     

Magnetization distributions in bulk magnetic material

Knowledge of the internal magnetization distributionsM(r)of polarizable media allows straightforward calculation of fields for any configuration which includes these media. Although useful calculations have been made using an assumedM(r), little work directed at calculatingM(r)has been done. This paper includes assumptions that, in addition to Maxwell's equations, are sufficient for determining the resultant integral equation. A method for the solution of this equation forM(r)is also presented. As an example, the nonuniform demagnetizing fields and magnetization distributions are calculated for cylinders of isotropic magnetic material. The results for these samples are compared with experimentally determined values and show average errors less than 9 percent forM(r).     

优秀音视频产品推荐

纵观当下的音视频市场，各种产品呈花齐放的态势，但功能上的差别却让不同的产品又各有优势。为了给大家提供一个选购依据，本文特挑选部分优秀音视频产品供大家参考。