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991.
Jin Chuan Wu Yew Kong Wong Kiat Wei Chang Chor Yong Tay Yvonne Chow Mmr Talukder 《Biocatalysis and Biotransformation》2013,31(6):459-463
Mucor javanicus lipase was entrapped in alginate-silica hybrid gel beads with or without simultaneous cross-linking with glutaraldehyde. The activity and recovery of activity on immobilization of the enzyme entrapped in the hybrid beads were 1.4 and 1.7 times higher than those of the enzyme entrapped in the simple alginate beads. Entrapment with simultaneous cross-linking in the hybrid beads further improved the enzyme activity (1.6 times) and activity recovery (1.7 times) compared to those of the enzyme entrapped in the hybrid beads without simultaneous cross-linking. The leakage of the enzyme entrapped in the hybrid beads with simultaneous cross-linking was only 50% that of the enzyme entrapped in the simple alginate beads. 相似文献
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994.
The function of the brainstem Hap1–Ahi1 complex in the regulation of feeding behavior was investigated. When mice were fasted or treated with 2-deoxy-d-glucose (2-DG), Hap1–Ahi1 was significantly upregulated. By using streptozotocin (STZ) to decrease the circulating insulin in mice, Hap1–Ahi1 was significantly increased. Furthermore, intra-brain injection of insulin decreased the expression of Hap1–Ahi1 in the brainstem. Moreover, when we knocked down the expression of brainstem Hap1 by RNAi, the mice showed decreased food intake and lower body weights. Collectively, our results indicate that the Hap1–Ahi1 complex in the brainstem works as a sensor for insulin signals in feeding control.
Structured summary
Ahi1physically interacts with Hap1: shown by anti bait coimmunoprecipitation (view interactions 1, 2) 相似文献995.
Mathematical models of bacterial populations are often written as systems of partial differential equations for the densities
of bacteria and concentrations of extracellular (signal) chemicals. This approach has been employed since the seminal work
of Keller and Segel in the 1970s (Keller and Segel, J. Theor. Biol. 30:235–248, 1971). The system has been shown to permit travelling wave solutions which correspond to travelling band formation in bacterial
colonies, yet only under specific criteria, such as a singularity in the chemotactic sensitivity function as the signal approaches
zero. Such a singularity generates infinite macroscopic velocities which are biologically unrealistic. In this paper, we formulate
a model that takes into consideration relevant details of the intracellular processes while avoiding the singularity in the
chemotactic sensitivity. We prove the global existence of solutions and then show the existence of travelling wave solutions
both numerically and analytically. 相似文献
996.
997.
Fibroblast growth factor homologous factors (FHFs, FGF11-14) bind to the C termini (CTs) of specific voltage-gated sodium channels (VGSC) and thereby regulate their function. The effect of an individual FHF on a specific VGSC varies greatly depending upon the individual FHF isoform. How individual FHFs impart distinctive effects on specific VGSCs is not known and the specificity of these pairwise interactions is not understood. Using several biochemical approaches combined with functional analysis, we mapped the interaction site for FGF12B on the Na(V)1.5 C terminus and discovered previously unknown determinants necessary for FGF12 interaction. Also, we demonstrated that FGF12B binds to some, but not all Na(V)1 CTs, suggesting specificity of interaction. Exploiting a human single nucleotide polymorphism in the core domain of FGF12 (P149Q), we identified a surface proline that contributes a part of this pairwise specificity. This proline is conserved among all FHFs, and mutation of the homologous residue in FGF13 also leads to loss of interaction with a specific VGSC CT (Na(V)1.1) and loss of modulation of the resultant Na(+) channel function. We hypothesized that some of the specificity mediated by this proline may result from differences in the affinity of the binding partners. Consistent with this hypothesis, surface plasmon resonance data showed that the P149Q mutation decreased the binding affinity between FHFs and VGSC CTs. Moreover, immunocytochemistry revealed that the mutation prevented proper subcellular targeting of FGF12 to the axon initial segment in neurons. Together, these results give new insights into details of the interactions between FHFs and Na(V)1.x CTs, and the consequent regulation of Na(+) channels. 相似文献
998.
Acid-base (AB) interactions play the most important role in bacterial attachment to surfaces and can be quantified based on electron donor/electron acceptor data from contact angle measurement (CAM) according to the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory. It follows that the XDLVO theory could fail to explain attachment numbers if differences in AB interactions between strains are not apparent by CAM. This study aimed to investigate the validity of the above assumptions by comparing empirical data on attachment of six bacterial strains (three strains of Campylobacter jejuni and three strains of Salmonella) to stainless steel and XDLVO theory predictions. A significant difference (P < 0.05) in AB interactions, apparent by CAM, between C. jejuni strains allowed prediction of attachment of this species by the XDLVO theory. However, the theory failed to explain the attachment numbers for Salmonella due to similar AB interactions, as established by CAM, between the three Salmonella strains. Qualitative analysis of AB interactions by microbial adhesion to solvents (MATS) revealed a significant difference (P < 0.05) in electron donor property between the three Salmonella strains suggesting that these strains may differ with respect to AB interactions. No significant correlation with respect to electron donor property (P = 0.502, r2 = 12%) was apparent between CAM and MATS. These data suggest that CAM may not always reflect exactly AB interactions and that the difference in the outcomes from MATS and CAM should be considered when the XDLVO theory is used to predict bacterial attachment to surfaces. 相似文献
999.
Xiao C Sun C Han W Pan F Dan Z Li Y Song ZG Jin YH 《Bioorganic & medicinal chemistry》2011,19(23):7100-7110
A series of purine nucleoside analogues bearing an aryl and hetaryl group in position 6 were prepared and their biological activities were assessed by in vitro CDK1/Cyclin B1 and CDK2/Cyclin A2 kinase assay. From the synthesized chemicals, three Xylocydine derivatives 3h, 3i, and 3j exhibited specific inhibitory activities on CDK2/Cyclin A2 with IC(50) values of 4.6, 4.8, and 55 μM, respectively. Those three compounds all induced G1/S phase arrest in Human epithelial carcinoma cell line (HeLa), and the results suggested they may inhibit CDK2 activity in vitro. Furthermore, molecular modeling study, their docking into Cyclin Dependant Kinase 2 (CDK2) active site showed high docking scores. Taken together, these data suggest that, those three compounds are good inhibitors of CDK2 for studying this kinase signal transduction pathway in cell system. 相似文献
1000.
5-Hydroxymethylcytosine (5-hmC) is a newly discovered DNA base in mammalian cells that is believed to be another important epigenetic modification. Here we report the use of a methylation-insensitive restriction enzyme TaqαI coupled with selective chemical labeling of 5-hmC in a combined glycosylation restriction analysis (CGRA) to detect 5-hmC in TCGA sequences. This method, differentiates fully versus hemi-hydroxymethylated cytosine in the CpG dinucleotide, adds a new tool to facilitate biological studies of 5-hmC. 相似文献