Evaluation of the overall process on bioethanol production from miscanthus hydrolysates obtained by dilute acid pretreatment

In this study, dilute sulfuric acid pretreatment was performed to improve the sugars recovery from Korean Miscanthus straw. The effect of pretreatment conditions on solubilized xylose was fundamentally investigated for the efficient removal of xylan. The optimal conditions were determined using a statistical method, and were shown to be a temperature of 121.6°C, an acid concentration of 1.1%, and a reaction time of 12.8 min. The combined severity factor was shown to be 1.1 under the optimum conditions. Following the pretreatment, the solubilized xylose in liquid fraction was found to be 71.2%, and about 72.6% of the solid was recovered. After enzymatic hydrolysis, about 86.4% glucose conversion was achieved when the pretreated biomass was used as a substrate, with the conversion being improved 4-fold compared with the control (untreated). The hydrolysates, approximately 10 g/L glucose, were applied to the fermentation of Saccharomyces cerevisiae K35, and the ethanol yield was about 96%. The overall process was evaluated based on the material balance, and the results show that approximately 172 g bioethanol can be produced when 1,000 g Miscanthus straw is loaded into the process.     

Recapitulation of molecular regulators of nuclear motion during cell migration

Cell migration is a highly orchestrated cellular event that involves physical interactions of diverse subcellular components. The nucleus as the largest and stiffest organelle in the cell not only maintains genetic functionality, but also actively changes its morphology and translocates through dynamic formation of nucleus-bound contractile stress fibers. Nuclear motion is an active and essential process for successful cell migration and nucleus self-repairs in response to compression and extension forces in complex cell microenvironment. This review recapitulates molecular regulators that are crucial for nuclear motility during cell migration and highlights recent advances in nuclear deformation-mediated rupture and repair processes in a migrating cell.     

Synthesis of pyrrolo[2,3-d]pyrimidine derivatives and their antiproliferative activity against melanoma cell line

Synthesis of a new series of diarylureas and amides having pyrrolo[2,3-d]pyrimidine scaffold is described. Their in vitro antiproliferative activities against A375 human melanoma cell line and HS 27 fibroblast cell line were tested and the effect of substituents on pyrrolo[2,3-d]pyrimidine was investigated. The newly synthesized compounds, except N-acetyl derivatives (Id, Ie, and Im), generally showed superior or similar activity against A375 to Sorafenib. Among all of these derivatives, compounds Iq and Ir having imidazole and morpholine moieties, respectively, showed the most potent antiproliferative activity against A375.     

Aminoquinoline derivatives with antiproliferative activity against melanoma cell line

The synthesis of a novel series of aminoquinoline derivatives 1a–p and their antiproliferative activities against A375 human melanoma cell line were described. Most compounds showed superior antiproliferative activities to Sorafenib as a reference compound. Among them, quinolinyloxymethylphenyl compounds 1k and 1l exhibited potent activities (IC₅₀ = 0.77 and 0.79 μM, respectively) and excellent selectivity against melanoma and fibroblast cell lines.     

生物医学工程的精要、责任和展望

作为工程学的直属分支,建立生物医学工程学科的主要目的不是为了开辟一个新的科学研究领域,而是为了借助工程学的方法来解决生物医学领域所面临的实际问题,以及借助工程师们所接受的专业训练、所拥有的专业知识、所具备的工作技巧来提高医疗服务的质量和效果。工程学与生物医学的结合已取得了一些具有里程碑性质的成果。在中低收入国家,例如中国,生物医学工程有责任保证合理使用专业技术,为低廉、可靠、有效的医疗服务提供支持。本文将根据可预见和不可预见的学科发展限制和困难,对学科发展的现实目标和责任进行严肃、冷静地讨论。     

In situ assembly states of (Na+,K+)-pump ATPase in human erythrocytes. Radiation target size analyses

The in situ assembly state of the (Na+,K+)-pump ATPase of human erythrocytes was studied by applying the classical target theory to radiation inactivation data of the ouabain-sensitive sodium efflux and ATP hydrolysis. Erythrocytes and their extensively washed white ghosts were irradiated at -45 to -50 degrees C with an increasing dose of 1.5-MeV electron beam, and after thawing, the Na+-pump flux and/or enzyme activities were assayed. Each activity measured was reduced as a simple exponential function of radiation dose, from which a radiation sensitive mass (target size) was calculated. When intact cells were used, the target sizes for the pump and for the ATPase activities were equal and approximately 620,000 daltons. The target size for the ATPase activity was reduced to approximately 320,000 daltons if the cells were pretreated with digitoxigenin. When ghosts were used, the target size for the ATPase activity was again approximately 320,000 daltons. Our target size measurements together with other information available in literature suggest that (Na+,K+)-pump ATPase may exist in human erythrocytes either as a tetramer of alpha beta or as a dimer of alpha beta in tight association with other protein mass, probably certain glycolytic enzymes, and that this tetrameric or heterocomplex association is dissociable by digitoxigenin treatment or by extensive wash during ghost preparation.     

Detection of β-Glucosidase Activity in Polyacrylamide Gels with Esculin as Substrate

β-Glucosidase can be located after nondenaturing polyacrylamide gel electrophoresis by incubating the gel with 0.1% esculin and 0.03% ferric chloride. The esculetin released from esculin by β-glucosidase action reacts with ferric ion to produce a black band, corresponding to the β-glucosidase, against the transparent background.     

Role of laccase in lignin degradation by white-rot fungi

Abstract Laccase is commonly found in white-rot fungi and catalyses the abstraction of one electron from the phenolic hydroxyl group to polymerize or depolymerize lignin model compounds. Laccase degrades both β-1 and β-O-4 dimers via C _α - C _β cleavage, C _α oxidation and alkyl-aryl cleavage. Also, aromatic ring cleavage may be detected following the action of laccase. Laccase can also oxidize non-phenolic compounds when primary mediators, such as 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate), are co-present. Laccase produces Mn(III) chelates which allow wood-decaying enzymes to penetrate wood cell walls. Laccase is considered to be capable of degrading lignin together with lignin peroxidase and manganese peroxidase.     

Towards biomarker-dependent individualized chemotherapy: Exploring cell-specific differences in oxaliplatin–DNA adduct distribution using accelerator mass spectrometry

Oxaliplatin is a third-generation platinum-based anticancer drug that is currently used in the treatment of metastatic colorectal cancer. Oxaliplatin, like other platinum-based anticancer drugs such as cisplatin and carboplatin, is known to induce apoptosis in tumor cells by binding to nuclear DNA, forming monoadducts, and intra- and interstrand diadducts. Previously, we reported an accelerator mass spectrometry (AMS) assay to measure the kinetics of oxaliplatin-induced DNA damage and repair [Hah, S. S.; Sumbad, R. A.; de Vere White, R. W.; Turteltaub, K. W.; Henderson, P. T. Chem. Res. Toxicol. 2007, 20, 1745]. Here, we describe another application of AMS to the measurement of oxaliplatin–DNA adduct distribution in cultured platinum-sensitive testicular (833 K) and platinum-resistant breast (MDA-MB-231) cancer cells, which resulted in elucidation of cell-dependent differentiation of oxaliplatin–DNA adduct formation, implying that differential adduction and/or accumulation of the drug in cellular DNA may be responsible for the sensitivity of cancer cells to platinum treatment. Ultimately, we hope to use this method to measure the intrinsic platinated DNA adduct repair capacity in cancer patients for use as a biomarker for diagnostics or a predictor of patient outcome.