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241.
Hong Er Tian Yong Sheng Gao Feng Min Li Fuli Zeng 《Biological trace element research》2003,93(1-3):257-269
Scanning electron microscopic and energy-dispersive X-ray analyses were used to study the distributions of different types
of elements in the epidermis, exodermis, endodermis, and vascular cylinder of the fracture face in the Lathyrus sativus L. roots in the presence or absence of Eu3+. Some index of the biological activity related to the elements binding with protein were determined also. The results showed
that the tissular distributions of elements in the fracture face are different in the presence and absence of Eu3+. The atomic percentages of P, S, Ca, and Mn were influenced more than those of other elements. Eu3+ promoted the biological activities of various kinds of element. The one possible mechanism changing the biological activities
was that the reaction of Eu3+
Eu2+ would influence the electron capture or transport in elements of binding protein. Another mechanism was that CaM-Ca2+ becoming CaM-Eu3+ through Eu3+ instead of Ca2+ would affect the biological activity of elements by regulating the Ca2+ level in the plant cell. 相似文献
242.
Lee KH Shin SY Hong JE Yang ST Kim JI Hahm KS Kim Y 《Biochemical and biophysical research communications》2003,309(3):591-597
Spinigerin is a linear antibacterial peptide derived from a termite insect. It consists of 25 amino acids and is devoid of cysteines. Spinigerin displays good lytic activities against Gram-positive and Gram-negative bacteria, but has no hemolytic activities against human erythrocytes. In this study, we present a three-dimensional solution structure of spinigerin in SDS micelles. According to CD data spinigerin has an alpha-helical conformation in the presence of TFE, DPC micelles, and SDS micelles. The three-dimensional structure of spinigerin as determined by NMR spectroscopy contains a stable alpha-helix from Lys4 to Thr23. Spinigerin (4-21), an 18-residue fragment from Lys4 to Leu21, contains a similar content of alpha-helical structure compared to native spinigerin and was found to retain antibacterial activity, too. Therefore, this alpha-helical structure and the strong electrostatic attraction between four Lys and three Arg residues in spinigerin and the negatively charged polar head groups of the phospholipids on the membrane surface play important roles in disrupting membrane and subsequent cell death. 相似文献
243.
244.
Hong Li 《Theorie in den Biowissenschaften》2013,132(1):1-16
The systems genetics is an emerging discipline that integrates high-throughput expression profiling technology and systems biology approaches for revealing the molecular mechanism of complex traits, and will improve our understanding of gene functions in the biochemical pathway and genetic interactions between biological molecules. With the rapid advances of microarray analysis technologies, bioinformatics is extensively used in the studies of gene functions, SNP–SNP genetic interactions, LD block–block interactions, miRNA–mRNA interactions, DNA–protein interactions, protein–protein interactions, and functional mapping for LD blocks. Based on bioinformatics panel, which can integrate “-omics” datasets to extract systems knowledge and useful information for explaining the molecular mechanism of complex traits, systems genetics is all about to enhance our understanding of biological processes. Systems biology has provided systems level recognition of various biological phenomena, and constructed the scientific background for the development of systems genetics. In addition, the next-generation sequencing technology and post-genome wide association studies empower the discovery of new gene and rare variants. The integration of different strategies will help to propose novel hypothesis and perfect the theoretical framework of systems genetics, which will make contribution to the future development of systems genetics, and open up a whole new area of genetics. 相似文献
245.
This report assessed the effect of overexpressing Cu,Zn superoxide dismutase (SOD) and/or catalase on the interaction of mononuclear cells (MNCs) and endothelial cells (ECs). ECs were obtained from the aorta of wild-type mice and transgenic mice overexpressing Cu,ZnSOD and/or catalase. MNCs were obtained from wild-type mice. Treatment of wild-type ECs with CuSO4-oxidized low-density lipoprotein (oxLDL) significantly elevated the expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) and increased the adherence of MNCs. Overexpression of Cu,ZnSOD and/or catalase in ECs attenuated the adherence of MNCs and the expression of cell adhesion molecules induced by oxLDL. For example, ECs overexpressing Cu,ZnSOD and/or catalase showed significantly less expression of VCAM-1 and ICAM-1 and less number of adherent MNCs than wild-type ECs. Moreover, ECs overexpressing Cu,ZnSOD and catalase in combination showed significantly less expression of VCAM-1 and ICAM-1 and less number of adherent MNCs than those overexpressing either Cu,ZnSOD or catalase alone. These results suggest that combinational overexpression of Cu,ZnSOD and catalase can reduce the expression of cell adhesion molecules and inhibit the adherence of leukocyte to ECs more efficiently than overexpression of Cu,ZnSOD or catalase alone. 相似文献
246.
林火是樟子松林重要的干扰因子,通过空间代替时间对地表火干扰时间序列上的天然樟子松林进行全林木定位调查,以单木竞争模型分析林分不同组分的竞争强度,通过Kriging法估计了火后林下更新幼树的密度。结果表明,存活林木各组分的竞争强度均显著地降低;地表火干扰12 a后存活林木各组分的竞争强度均比火后1 a存活林木相应各组分的竞争强度显著地降低;另外,火后更新幼树也更多地趋于地表火干扰形成的林隙中。因此,地表火干扰时间序列上林木竞争强度显著的持续降低,火后存活个体将有更充足的可利用资源和环境,林火成为樟子松林发育演替的重要驱动力。 相似文献
247.
Thermodynamic-based constraints on biochemical fluxes and concentrations are applied in concert with mass balance of fluxes in glycogenesis and glycogenolysis in a model of hepatic cell metabolism. Constraint-based modeling methods that facilitate predictions of reactant concentrations, reaction potentials, and enzyme activities are introduced to identify putative regulatory and control sites in biological networks by computing the minimal control scheme necessary to switch between metabolic modes. Computational predictions of control sites in glycogenic and glycogenolytic operational modes in the hepatocyte network compare favorably with known regulatory mechanisms. The developed hepatic metabolic model is used to computationally analyze the impairment of glucose production in von Gierke's and Hers' diseases, two metabolic diseases impacting glycogen metabolism. The computational methodology introduced here can be generalized to identify downstream targets of agonists, to systematically probe possible drug targets, and to predict the effects of specific inhibitors (or activators) on integrated network function. 相似文献
248.
New ternary transition metal complexes of formulations [Ni(bpa)(p-AB)Cl]n · 3nH2O (bpa = 2,2′-bipyridylamine, p-AB = aminobenzenecarboxylic acid) (1), [Cu(bpa)(p-AB)Cl] · H2O (2), [Zn(bpa)(p-AB)2] · H2O (3) are prepared, their structural features are characterized by crystal structural studies, and their DNA binding propensity has been evaluated by fluorescence and viscosity method. In complex 2 and 3, both bpa and p-AB act as the bidentate N and O-donor ligand, respectively. While in complex 1, p-AB acts as a rare tridentate ligand. In the packing pattern of each complex, π-π interaction in their solid state is also described. The complexes show the competitive inhibition of ethidium binding to DNA, and the DNA binding propensity can be reflected as the relative order: 1 > 2 > 3. 相似文献
249.
Insulin has a largely alpha-helical structure and exists as a mixture of hexameric, dimeric, and monomeric states in solution, depending on the conditions: the protein is monomeric in 20% acetic acid. Insulin forms amyloid-like fibrils under a variety of conditions, especially at low pH. In this study we investigated the fibrillation of monomeric human insulin by monitoring changes in CD, attenuated total reflectance-Fourier transform infrared spectroscopy, 8-anilinonaphthalenesulfonic acid fluorescence, thioflavin T fluorescence, dynamic light scattering, and H/D exchange during the initial stages of the fibrillation process to provide insight into early events involving the monomer. The results demonstrate the existence of structural changes occurring before the onset of fibril formation, which are detectable by multiple probes. The data indicate at least two major populations of oligomeric intermediates between the native monomer and fibrils. Both have significantly non-native conformations, and indicate that fibrillation occurs from a beta-rich structure significantly distinct from the native fold. 相似文献
250.