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121.
Guo-peng Miao Chuan-shu Zhu Jun-tao Feng Juan Han Xiao-Wei Song Xing Zhang 《Plant Cell, Tissue and Organ Culture》2013,112(1):109-116
The relationships between aggregate cell types, cell growth, and the triptolide, wilforgine, and wilforine content in aggregate cell suspension cultures of Tripterygium wilfordii Hook. f. were examined. Aggregate cells larger than 2?mm grew quickly and constituted the majority of the white aggregates. The accumulation of triptolide was strongly correlated with the size of the aggregates and the length of the culture period. The aggregates 0.5?C2?mm in diameter accumulated higher triptolide content than those with other sizes throughout the culture. However, the size of the aggregate cells did not significantly affect on the wilforgine and wilforine content. Two other kinds of aggregate cells, the brown and green aggregate cells, also formed in the suspension cultures. The smallest aggregates (0.1?C0.5?mm) had a lower biomass and growth rate and had more chloroplasts and higher alkaloid content. The results of this study can be used to improve the selection process for the mass production of triptolide, wilforgine, and wilforine from cell suspension cultures. 相似文献
122.
Ming Miao Eva Sitarz Catherine M. Bellingham Emily Won Lisa D. Muiznieks Fred W. Keeley 《Biopolymers》2013,99(6):392-407
Elastin is the polymeric, extracellular matrix protein that provides properties of extensibility and elastic recoil to large arteries, lung parenchyma, and other tissues. Elastin assembles by crosslinking through lysine residues of its monomeric precursor, tropoelastin. Tropoelastin, as well as polypeptides based on tropoelastin sequences, undergo a process of self‐assembly that aligns lysine residues for crosslinking. As a result, both the full‐length monomer as well as elastin‐like polypeptides (ELPs) can be made into biomaterials whose properties resemble those of native polymeric elastin. Using both full‐length human tropoelastin (hTE) as well as ELPs, we and others have previously reported on the influence of sequence and domain arrangements on self‐assembly properties. Here we investigate the role of domain sequence and organization on the tensile mechanical properties of crosslinked biomaterials fabricated from ELP variants. In general, substitutions in ELPs involving similiar domain types (hydrophobic or crosslinking) had little effect on mechanical properties. However, modifications altering either the structure or the characteristic sequence style of these domains had significant effects on such properties. In addition, using a series of deletion and replacement constructs for full‐length hTE, we provide new insights into the role of conserved domains of tropoelastin in determining mechanical properties. © 2012 Wiley Periodicals, Inc. Biopolymers 99: 392–407, 2013. 相似文献
123.
Wei‐Li Quan Xia‐Lin Zheng Xin‐Xin Li Xing‐Miao Zhou Wei‐Hua Ma Xiao‐Ping Wang 《Entomologia Experimentalis et Applicata》2013,146(3):398-403
Although parasitoids ultimately kill their host, koinobiont parasitoids must protect not only themselves but also their hosts against extreme environments. In this study, the parasitism rate of Chilo suppressalis Walker (Lepidoptera: Pyralidae) was investigated, and the average body weights, supercooling points, and concentrations of glycerol (acting as a cryoprotectant) in the hemolymph were compared between parasitized and non‐parasitized larvae. Five species of koinobiont endoparasitoids parasitized the overwintering C. suppressalis larvae and the total parasitism rate was 47.6% (n = 1 537). Average body weight of parasitized larvae was significantly lower than that of non‐parasitized larvae, and the parasitism rate of the lighter group (20–30 mg) was highest. The supercooling point of parasitized C. suppressalis larvae (?15.7 ± 0.3 °C) was significantly lower than that of the non‐parasitized larvae (?14.3 ± 0.2 °C). In addition, supercooling points were not correlated with body weights between parasitized and non‐parasitized larvae, indicating that cold hardiness of parasitized larvae was enhanced by endoparasitoids. Furthermore, the concentration of glycerol in the hemolymph was significantly higher in parasitized larvae (205.0 ± 7.1 μmol ml?1) than in non‐parasitized larvae (169.8 ± 14.4 μmol ml?1), which suggests that the mechanism that decreases the supercooling point of parasitized larvae was associated with glycerol. All these results indicated that the cold hardiness of parasitized C. suppressalis larvae was enhanced by their endoparasitoids, which benefitted overwintering endoparasitoids. 相似文献
124.
Miao Gao Hui Yang Ji Zhao Jun Liu Yan-hua Sun Yu-jiong Wang Jian-guang Sun 《Antonie van Leeuwenhoek》2013,103(3):647-653
A novel Gram-positive, rod-shaped, motile, spore-forming, nitrogen-fixing bacterium, designated strain 112T, was isolated from cabbage rhizosphere in Beijing, China. The strain was found to grow at 10–40 °C and pH 4–11, with an optimum of 30 °C and pH 7.0, respectively. Phylogenetic analysis based on a fragment of the full-length 16S rRNA gene sequence revealed that strain 112T is a member of the genus Paenibacillus. High levels of 16S rRNA gene similarities were found between strain 112T, Paenibacillus sabinae DSM 17841T (97.82 %) and Paenibacillus forsythiae DSM 17842T (97.22 %). However, the DNA–DNA hybridization values between strain 112T and the type strains of these two species were 10.36 and 6.28 %, respectively. The predominant menaquinone was found to be menaquinone 7 (MK-7). The major fatty acids were determined to be anteiso-C15:0 and C16:0. The major polar lipids were found to be diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and unknown aminophospholipids. The cell wall peptidoglycan was found to contain meso-diaminopimelic acid. The DNA G+C content was determined to be 55.4 mol%. On the basis of its phenotypic characteristics, 16S rRNA gene sequence analysis and the value of DNA–DNA hybridization, strain 112T is considered to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus brassicae sp. nov. is proposed. The type strain is 112T (= ACCC 01125T = DSM 24983T). 相似文献
125.
126.
Meng Zhang Liang Dong Zhubing Shi Shi Jiao Zhen Zhang Wenqing Zhang Guoguang Liu Cuicui Chen Miao Feng Qian Hao Wenjia Wang Mengxin Yin Yun Zhao Lei Zhang Zhaocai Zhou 《Structure (London, England : 1993)》2013,21(4):680-688
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127.
基于多种方法的景观格局动态变化综合分析——以辽宁省铁岭市为例 总被引:2,自引:0,他引:2
景观格局变化一直是景观生态学研究的核心问题之一,也是相关生态和环境过程研究的基础.本文应用3S技术,综合传统的空间统计分析、转移矩阵、景观指数和景观动态指数、Kappa指数系列,并引入模糊Kappa指数方法,以铁岭市2002-2011年间景观格局变化为例进行了综合研究.结果表明:铁岭市景观空间格局在研究时段内发生一定程度的变化.旱地面积大幅增加,水田面积明显减少,各景观类型之间均有相互转化.景观格局总体的变化趋势是形状趋于复杂、异质性增加、破碎化加剧,人为干扰的影响较明显.研究区域2002-2007年综合景观动态度指数明显高于2007-2011年,景观动态总体呈现放缓趋势.通过Kappa指数系列可知,研究时段内研究区景观变化由景观类型之间变化为主逐渐转变为各类斑块位置上的变化为主.应用多种方法进行综合分析更能全面有效地反映景观格局变化. 相似文献
128.
目的探讨EFS和DAP两种玻璃化冷冻方法对不同品系小鼠胚胎冷冻的效果。方法6个品系小鼠(KM、ICR、BALB/c、C57BL/6J、OB/OB、LAP/~TAOF59)的2-cell胚胎分别用EFS和DAP两种玻璃化冷冻方法进行冷冻和复苏,比较两种冷冻方法的胚胎复苏率和着床率。结果6个品系小鼠冷冻胚胎EFS方法的平均复苏率为69.97%(47.9%~83.6%),DAP方法的平均复苏率47.23%(26.3%-76.7%),EFS方法明显优于DAP方法。其中KM、ICR和BALB/c小鼠EFS方法的冷冻复苏率显著高于DAP方法(P〈0.01);冻融胚胎移植后EFS方法的平均着床率27.23%(1.75%一45.0%),DAP方法的平均着床率31.43%(7.0%一46.3%)。除KM、ICR小鼠外,其他4个品系小鼠的着床率DAP方法高于EFS方法。结论KM和ICR远交群小鼠胚胎适合用EFS方法冷冻保存;C57BL/6J、OB/OB、LAP/aTAOF59三个品系小鼠DAP方法优于EFS方法,但差异不大;BALB/c小鼠两种玻璃化冷冻方法的冻融胚胎着床率均较低,需进一步研究。 相似文献
129.
Xumiao Chen Xiaozhong Hu Xiaofeng Lin Khaled A.S. Al-Rasheid Honggang Ma Miao Miao 《European journal of protistology》2013,49(4):611-622
This paper investigates the morphology, ontogenesis and small subunit (SSU) rRNA gene-based phylogeny of a new urostylid ciliate, Bakuella subtropica sp. n., discovered from the estuary of the Pearl River in Guangzhou, southern China. The new species is diagnosed by its elongate body, one buccal and one parabuccal cirrus, midventral complex comprised of 9–23 midventral pairs and one or two midventral rows extending to four fifths of body length, yellow-brown to yellow-greenish cortical granules and an estuary habitat. Its main ontogenetic features are: (1) in the proter, the parental adoral zone of membranelles is completely renewed by new structures and old midventral pairs join the formation of frontal-midventral-transverse cirral anlagen (FVT-anlagen); (2) in the opisthe, the oral primordium originates apokinetally, FVT-anlagen are formed besides and some old midventral cirri join the formation; (3) the anlagen for marginal rows and dorsal kineties develop intrakinetally; and (4) the numerous macronuclear nodules fuse into a single mass before dividing. Based on the SSU rDNA sequences, phylogenetic analyses show a close relationship between Bakuella subtropica sp. n., Apobakuella and Neobakuella, forming a clade separated from the other genera in the family Bakuellidae. Available morphological and ontogenetic data challenge the monophyly of Bakuellidae. 相似文献
130.
Quan Luo Chunqiu Zhang Lu Miao Dongmei Zhang Yushi Bai Chunxi Hou Junqiu Liu Fei Yan Ying Mu Guimin Luo 《Amino acids》2013,44(3):1009-1019
By combining computational design and site-directed mutagenesis, we have engineered a new catalytic ability into the antibody scFv2F3 by installing a catalytic triad (Trp29–Sec52–Gln72). The resulting abzyme, Se-scFv2F3, exhibits a high glutathione peroxidase (GPx) activity, approaching the native enzyme activity. Activity assays and a systematic computational study were performed to investigate the effect of successive replacement of residues at positions 29, 52, and 72. The results revealed that an active site Ser52/Sec substitution is critical for the GPx activity of Se-scFv2F3. In addition, Phe29/Trp–Val72/Gln mutations enhance the reaction rate via functional cooperation with Sec52. Molecular dynamics simulations showed that the designed catalytic triad is very stable and the conformational flexibility caused by Tyr101 occurs mainly in the loop of complementarity determining region 3. The docking studies illustrated the importance of this loop that favors the conformational shift of Tyr54, Asn55, and Gly56 to stabilize substrate binding. Molecular dynamics free energy and molecular mechanics-Poisson Boltzmann surface area calculations estimated the pK a shifts of the catalytic residue and the binding free energies of docked complexes, suggesting that dipole–dipole interactions among Trp29–Sec52–Gln72 lead to the change of free energy that promotes the residual catalytic activity and the substrate-binding capacity. The calculated results agree well with the experimental data, which should help to clarify why Se-scFv2F3 exhibits high catalytic efficiency. 相似文献