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941.
942.
Takuma Suematsu Shin‐ichi Yokobori Hiroyuki Morita Shigeo Yoshinari Takuya Ueda Kiyoshi Kita Nono Takeuchi Yoh‐ichi Watanabe 《Molecular microbiology》2010,75(6):1445-1454
Translation elongation factor G (EF‐G) in bacteria plays two distinct roles in different phases of the translation system. EF‐G catalyses the translocation of tRNAs on the ribosome in the elongation step, as well as the dissociation of the post‐termination state ribosome into two subunits in the recycling step. In contrast to this conventional view, it has very recently been demonstrated that the dual functions of bacterial EF‐G are distributed over two different EF‐G paralogues in human mitochondria. In the present study, we show that the same division of roles of EF‐G is also found in bacteria. Two EF‐G paralogues are found in the spirochaete Borrelia burgdorferi, EF‐G1 and EF‐G2. We demonstrate that EF‐G1 is a translocase, while EF‐G2 is an exclusive recycling factor. We further demonstrate that B. burgdorferi EF‐G2 does not require GTP hydrolysis for ribosome disassembly, provided that translation initiation factor 3 (IF‐3) is present in the reaction. These results indicate that two B. burgdorferi EF‐G paralogues are close relatives to mitochondrial EF‐G paralogues rather than the conventional bacterial EF‐G, in both their phylogenetic and biochemical features. 相似文献
943.
Objectives: Translational research using adult stem cells derived from various tissues has been highlighted in cell‐based therapy. However, there are many limitations to using conventional culture systems of adult stem cells for clinically applicability, including limited combinations of cytokines and use of nutrients derived from animals. Here, we have investigated the effects of placental extract (PE) for culture of placenta‐derived stem cells (PDSCs) as well as their potential for hepatogenic differentiation. Materials and methods: Placental extract, extracted using water‐soluble methods, was used as a supplement for culture of PDSCs. Cell viability was determined using the MTT assay, and cytokine assay was performed using Luminex assay kit. Gene expression, indocyanine green (ICG) up‐take, PAS (Periodic Acid‐Schiff) staining and urea production were also analysed. Results: The placental extract contained several types of cytokine and chemokine essential for maintenance and differentiation of stem cells. Expression of stemness markers in PDSCs cultured with PE is no different from that of PDSCs cultured with foetal bovine serum (FBS). After hepatogenic differentiation, expression patterns for hepatocyte‐specific markers in PDSCs cultured with PE were consistent and potential for hepatogenic differentiation of PDSCs cultured with PE was similar to that of PDSCs cultured with FBS, as shown by PAS staining and urea production assays. Conclusions: Our findings revealed that placental extract could be used as a new component for culture of adult stem cells, as well as for development of human‐based medium, in translational research for regenerative medicine. 相似文献
944.
Won Il Choi Kwang-Sik Choi Dong-Pyeo Lyu Jung-Su Lee Jongok Lim Seunghwan Lee Sang-Chul Shin Yeong-Jin Chung Young-Seuk Park 《Biodiversity and Conservation》2010,19(8):2291-2305
Fauna assemblages reflect their habitat relating to ecological function in an ecosystem. The functional groups are concerned
with how a resource is processed by different species to provide a specific ecosystem service or function. We elucidated seasonal
changes of coleopteran functional groups in forests, and evaluated their ecological roles related to available food resources.
Coleopteran communities were collected weekly or biweekly using Malaise traps at nine study sites in Japanese red pine forests
in Korea from late June to September 2005. Compositions of the functional groups were compared at the different sites and
at sampling times with respect to taxa richness and abundance. Cluster analysis and non-metric multidimensional scaling were
used to characterize spatial and temporal changes of functional groups. Herbivores and dead/live wood feeders regulating primary
production in the pine forests were the dominant coleopteran groups in July, followed by detritivores and predators that dominated
from July to August, resulting from the accumulation of detritus. Then, fungivores became dominant due to increased fungal
biomass in the forest. Seasonal changes of coleopteran functional groups shifted from regulators of primary production to
regulators of decomposition, reflecting their available food resources. In addition, abundance of detritivores and predators
were dependent on total abundance of coleopterans, suggesting that these two groups reflect their habitat condition. 相似文献
945.
Hiroki Shimizu Shinji Tanaka Tadashi Toki Isao Yasumatsu Toshihiko Akimoto Kaoru Morishita Tomonori Yamasaki Takanori Yasukochi Shin Iimura 《Bioorganic & medicinal chemistry letters》2010,20(17):5113-5118
Imidazo[1,2-b]pyridazine derivatives from high-throughput screening were developed as IKKβ inhibitors. By the optimization of the 3- and 6-position of imidazo[1,2-b]pyridazine scaffold, cell-free IKKβ inhibitory activity and TNFα inhibitory activity in THP-1 cell increased. Also, these compounds showed high kinase selectivity. The structure–activity relationship was revealed and the interaction model of imidazo[1,2-b]pyridazine compounds with IKKβ was constructed. 相似文献
946.
Jaeyoung Ko Hoosang Hwang Jungwook Chin Dongyup Hahn Jaehwan Lee Inho Yang Kyoungjin Shin Jungyeob Ham Heonjoong Kang 《Bioorganic & medicinal chemistry letters》2010,20(20):6017-6019
A novel class of natural PPAR agonists, 2,4-dimethyl-4-hydroxy-16-phenylhexadecanoic acid 1,4-lactone (1), were discovered in marine natural product libraries. The synthesis of 1 was accomplished starting from vinylmethyl ketone. Ring formation of the α,γ dialkyl γ-lactone was achieved via the stereo-controlled reaction of a ketyl radical anion with a chiral methacrylate. In the PPAR agonistic assay, the most potent of the four stereoisomers had EC50 values of 12 μM for mPPARα, 9 μM for mPPARδ and >100 μM for mPPARγ. 相似文献
947.
948.
Mingzhe Liu Hiroshi Jinmei Hiroshi Abe Yoshihiro Ito 《Bioorganic & medicinal chemistry letters》2010,20(9):2964-2967
A photoresponsive RNA aptamer to hemin was selected in vitro from a random sequence library of RNAs with azobenzene residues. The aptamer bound to hemin under visible light irradiation and was released by ultraviolet light. 相似文献
949.
950.
The kinetic and thermodynamic properties of a peptide–receptor interaction was investigated by measuring the adhesion force
in the reaction via atomic force microscopy (AFM). Trp-Lys-Tyr-Met-Val-D-Met (WKYMVm), considered as a model system in the
present study, is a potent neutrophil chemo-attractant. Since being identified as an agonist for formyl peptide receptor (FPR),
WKYMVm’s high affinity to FPR has been verified through investigation of its kinetic and physiological behaviors via conventional
methods. However, there have been no reports on the adhesion force of WKYMVm-FPR. In this research, we measured the adhesion
force of WKYMVm-FPR using AFM. Kinetic parameters obtained from the relationship between the adhesion force and loading rate
were used to characterize the thermodynamic properties of WKYMVm-hFPR binding. 相似文献