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11.
W. Y. Chan T. B. Ng Joyce S. Y. Lam Jack H. Wong K. T. Chu P. H. K. Ngai S. K. Lam H. X. Wang 《Applied microbiology and biotechnology》2010,85(4):985-993
Earlier investigations disclose that some plant ribosome-inactivating proteins (RIPs) adversely affect mouse embryonic development.
In the present study, a mushroom RIP, namely lyophyllin from Lyophyllum shimeji, was isolated, partially sequenced, and its translation inhibitory activity determined. Its teratogenicity was studied by
using a technique entailing microinjection and postimplantation whole-embryo culture. It was found that embryonic abnormalities
during the period of organogenesis from E8.5 to E9.5 were induced by lyophyllin at a concentration as low as 50 μg/ml, and
when the lyophyllin concentration was raised, the number of abnormal embryos increased, the final somite number decreased,
and the abnormalities increased in severity. The affected embryonic structures included the cranial neural tube, forelimb
buds, branchial arches, and body axis, while optic and otic placodes were more resistant. Lyophyllin at a concentration higher
than 500 μg/ml also induced forebrain blisters within the cranial mesenchyme. When the abnormal embryos were examined histologically,
an increase of cell death was found to be associated with abnormal structures, indicating that cell death may be one of the
underlying causes of teratogenicity of the mushroom RIP. This constitutes the first report on the teratogenicity of a mushroom
RIP. 相似文献
12.
The identification of angiogenic growth factors, such as vascular endothelial growth factor and fibroblast growth factor, has fueled interest in using such factors to induce therapeutic angiogenesis. The results of numerous animal studies and clinical trials have offered promise for new treatment strategies for various ischemic diseases. Increased understanding of the cellular and molecular biology of vessel growth has, however, prompted investigators and clinicians alike to reconsider the complexity of therapeutic angiogenesis. The realization that formation of a stable vessel is a complex, multistep process may provide useful insights into the design of the next generation of angiogenesis therapy. 相似文献
13.
14.
Cell death induced by Pteris semipinnata L. is associated with p53 and oxidant stress in gastric cancer cells 总被引:4,自引:0,他引:4
In this study, we demonstrated that Ent-11alpha-hydroxy-15-oxo-kaur-16-en-19-oic-acid (5F) had stronger cytotoxicity against MKN-45, a gastric cancer cell line bearing wild-type p53 than MKN-28, another gastric cancer cell line containing missense mutation in p53. The rapid increase of ROS level was involved in the mechanism of cytotoxicity. Classical features of apoptosis induced by 5F were observed in MKN-45 cells only or more significant in MKN-45 cells than MKN-28 cells. Translocation of Bax from cytosol to mitochondria, reduction of delta psi m and DNA fragmentation were induced by 5F in the p53-dependent manner. We conclude that the expression of Bax and its downstream molecules requires the presentation of a wild-type p53 in the cells treated by 5F. 相似文献
15.
Nie DY Ma QH Law JW Chia CP Dhingra NK Shimoda Y Yang WL Gong N Chen QW Xu G Hu QD Chow PK Ng YK Ling EA Watanabe K Xu TL Habib AA Schachner M Xiao ZC 《Neuron glia biology》2006,2(3):151-164
The molecular mechanisms underlying the involvement of oligodendrocytes in formation of the nodes of Ranvier (NORs) remain poorly understood. Here we show that oligodendrocyte-myelin glycoprotein (OMgp) aggregates specifically at NORs. Nodal location of OMgp does not occur along demyelinated axons of either Shiverer or proteolipid protein (PLP) transgenic mice. Over-expression of OMgp in OLN-93 cells facilitates process outgrowth. In transgenic mice in which expression of OMgp is down-regulated, myelin thickness declines, and lateral oligodendrocyte loops at the node-paranode junction are less compacted and even join together with the opposite loops, which leads to shortened nodal gaps. Notably, each of these structural abnormalities plus modest down-regulation of expression of Na(+) channel alpha subunit result in reduced conduction velocity in the spinal cords of the mutant mice. Thus, OMgp that is derived from glia has distinct roles in regulating nodal formation and function during CNS myelination. 相似文献
16.
West Nile virus (WNV) capsid (C) protein is one of the three viral structural proteins and it encapsidates the viral RNA to form the nucleocapsid. It is known to be a multifunctional protein involved in assembly and apoptosis. WNV C protein was previously found to be phosphorylated in infected cells and bioinformatic analysis revealed 5 putative phosphorylation sites at serine 26, 36, 83, 99 and threonine 100. Phosphorylation was abolished through mutagenesis of these putative phosphorylation sites to investigate how phosphorylation could affect the processes of nucleocapsid assembly like RNA binding, oligomerization and cellular localization. It was found that phosphorylation attenuated its RNA binding activity. Although oligomerization was not inhibited by mutagenesis of the putative phosphorylation sites, the rate of dimerization and oligomerization was affected. Hypophosphorylation of C protein reduced its nuclear localization efficiency and hence enhanced cytoplasmic localization. This study also revealed that although WNV C is phosphorylated in infected cells, the relative level of phosphorylation is reduced over the course of an infection to promote RNA binding and nucleocapsid formation in the cytoplasm. This is the first report to describe how dynamic phosphorylation of WNV C protein modulates the processes involved in nucleocapsid assembly. 相似文献
17.
Darren McMorran Dwayne Chung Kim Chung Monika Toth Oi Wah Liew Murat Muradoglu Tuck Wah Ng 《Analytical biochemistry》2016
During the collection phase of the dried blood spot method, practitioners need to ensure that there is no smearing of the blood sample on the filter paper or else readings from it will be invalid. This can be difficult to accomplish in the field if there is relative motion between the site of blood discharge on the finger and the filter paper. In this article, a gyroscope stabilization method is introduced and demonstrated to provide consistent and improved dried blood spot collection within a circular guide region notwithstanding the presence of rocking. 相似文献
18.
Joe Carver Domingos Ng Michelle Zhou Peggy Ko Dejin Zhan Mandy Yim David Shaw Brad Snedecor Michael W. Laird Steven Lang Amy Shen Zhilan Hu 《Biotechnology progress》2020,36(4):e2967
Historically, therapeutic protein production in Chinese hamster ovary (CHO) cells has been accomplished by random integration (RI) of expression plasmids into the host cell genome. More recently, the development of targeted integration (TI) host cells has allowed for recombination of plasmid DNA into a predetermined genomic locus, eliminating one contributor to clone-to-clone variability. In this study, a TI host capable of simultaneously integrating two plasmids at the same genomic site was used to assess the effect of antibody heavy chain and light chain gene dosage on antibody productivity. Our results showed that increasing antibody gene copy number can increase specific productivity, but with diminishing returns as more antibody genes are added to the same TI locus. Random integration of additional antibody DNA copies in to a targeted integration cell line showed a further increase in specific productivity, suggesting that targeting additional genomic sites for gene integration may be beneficial. Additionally, the position of antibody genes in the two plasmids was observed to have a strong effect on antibody expression level. These findings shed light on vector design to maximize production of conventional antibodies or tune expression for proper assembly of complex or bispecific antibodies in a TI system. 相似文献
19.
20.
Harnessing enzyme expression for production of target chemicals is a critical and multifarious process, where screening of different genes by inspection of enzymatic activity plays an imperative role. Here, we conceived an idea to improve the time-consuming and labor-intensive process of enzyme screening. Controlling cell growth was achieved by the Cluster Regularly Interspaced Short Palindromic Repeat (CRISPRi) system with different single guide RNA targeting the essential gene can (CRISPRi::CA) that encodes a carbonic anhydrase for CO2 uptake. CRISPRi::CA comprises a whole-cell biosensor to monitor CO2 concentration, ranging from 1% to 5%. On the basis of CRISPRi::CA, an effective and simple Direct Enzymatic Performance Evaluation & Determination (DEPEND) system was developed by a single step of plasmid transformation for targeted enzymes. As a result, the activity of different carbonic anhydrases corresponded to the colony-forming units. Furthermore, the enzymatic performance of 5-aminolevulinic acid synthetase (ALAS), which converts glycine and succinate-CoA to release a molecule of CO2, has also been distinguished, and the effect of the chaperone GroELS on ALAS enzyme folding was successfully identified in the DEPEND system. We provide a highly feasible, time-saving, and flexible technology for the screening and inspection of high-performance enzymes, which may accelerate protein engineering in the future. 相似文献