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151.
Due to the complexity of Plasmodium falciparumis genome, predicting secretory proteins of P. falciparum is more difficult than other species. In this study, based on the measure of diversity definition, a new K-nearest neighbor method, K-minimum increment of diversity (K-MID), is introduced to predict secretory proteins. The prediction performance of the K-MID by using amino acids composition as the only input vector achieves 88.89% accuracy with 0.78 Mathew’s correlation coefficient
(MCC). Further, the several reduced amino acids alphabets are applied to predict secretory proteins and the results show that
the prediction results are improved to 90.67% accuracy with 0.83 MCC by using the 169 dipeptide compositions of the reduced
amino acids alphabets obtained from Protein Blocks method. 相似文献
152.
千岛湖姥山马尾松种群结构和分布格局研究 总被引:2,自引:1,他引:1
为研究千岛湖马尾松(Pinus massoniana)种群动态变化,在姥山岛上设置面积为5.76 hm2的固定样地,进行群落学调查。根据野外调查的数据,对马尾松种群的结构和分布格局进行分析。结果表明:马尾松种群1、2级个体数极少,仅占样地中马尾松个体数的0.06%和1.01%,幼苗、幼树储备严重不足,5级个体的比例最高,达到28.28%,马尾松种群径级结构为纺锤型;马尾松种群的存活曲线为凸型。这些均表明马尾松种群的年龄结构趋向衰退型。但马尾松种群中树个体很多,在较长的时期内马尾松还不会退出群落。马尾松种群静态生命表也可看出中一些小型径级的死亡率为负值,也说明马尾松种群幼苗严重缺乏,种群呈衰退趋势。马尾松种群各径级和总体的分布格局均呈聚集分布,从小树→中树→大树聚集指数逐渐减小,种群呈扩散趋势。 相似文献
153.
Hongyan Han Qiang Ao Guoqiang Chen Shijie Wang Huancong Zuo 《Biotechnology letters》2010,32(4):585-591
Autologous nerve grafts are widely used in bridging critical gaps of peripheral nerves, but they remain associated with high
morbidity of the donor site and lack of full recovery. As an alternative, we have focused on chitosan nerve conduits filled
with a heparin-incorporated fibrin–fibronectin matrix serving as delivery systems for basic fibroblast growth factor (bFGF). The artificial nerve conduits were
used for repairing sciatic nerve defects of 10 mm in adult rats. Three months post-operation, the conduction velocity recovery
index (CVRI) and the muscle restoration rate (MRR) in animals of the experimental group were 32 ± 4.1 and 77.4 ± 7.9%, respectively,
which were significantly higher than those of the PBS control group (17.8 ± 1.9 and 66.7 ± 6.5%), and similar to those of
the autograft group (38.4 ± 3.9 and 81.3 ± 7.8%). These results were also consistent with the densities of regenerated axons
in the three groups, which were demonstrated by histomorphological analysis. 相似文献
154.
In this paper, the global robust stability problem of delayed Takagi–Sugeno fuzzy Hopfield neural networks with discontinuous
activation functions (TSFHNNs) is considered. Based on Lyapunov stability theory and M-matrices theory, we derive a stability criterion to guarantee the global robust stability of TSFHNNs. Compared with the existing
literature, we remove the assumptions on the neuron activations such as Lipschitz conditions, bounded, monotonic increasing
property or the assumption that the right-limit value is bigger than the left one at the discontinuous point. Finally, two
numerical examples are given to show the effectiveness of the proposed stability results. 相似文献
155.
AimsOne possible mechanism for epilepsy drug resistance is overexpression of P-glycoprotein in the blood–brain barrier, but whether (or which) antiepileptic drugs (AEDs) are transported by P-gp remains unclear. We evaluated AEDs as P-gp substrates using cell monolayers.Main methodsBi-directional transport assays and concentration equilibrium transport assays (CETAs) were performed for phenytoin (PHT), phenobarbital (PB), and ethosuximide (ESM) using wildtype Madin–Darby Canine Kidney II cell line MDCKII and porcine renal endothelial cell line LLC–PK1 cells and these cells transfected with human MDR1 cDNA to express P-gp.Key findingsWildtype cells demonstrated no efflux transport of PHT, PB, or ESM. In CETAs, both MDR1-transfected cell lines transported PHT from basolateral to apical when PHT loading concentrations were 5 or 10, but not 20 µg/ml. MDCK–MDR1 cells transported PB when initial concentrations were 10 or 20, but not 5 µg/ml. LLC–MDR1 did not transport PB. P-gp inhibitor verapamil blocked efflux transport. MDR1-transfected cells did not transport ESM at 5.6 or 56 µg/ml. Bi-directional transport assays demonstrated weak transport for PHT but not PB or ESM.SignificanceHuman P-gp transports PHT and PB, but not ESM, in a concentration dependent manner. CETA may be more sensitive than bi-directional assays to detect transport of drugs with high passive diffusion. Potential P-gp substrates should be tested at clinically relevant concentration ranges. 相似文献
156.
Yanxia Cui Zimei Wu Xiaoxu Liu Rui Ni Xuanxuan Zhu Lulu Ma Jianping Liu 《AAPS PharmSciTech》2010,11(2):878-884
Brucea javanica oil-loaded liposomes (BJOL) were prepared through thin film hydration method and characterized by transmission electron microscope,
dynamic light scattering, and differential scanning calorimetry. Acute toxicity of B. javanica oil (BJO) in liposomes was assessed by determining the number of deaths of Kunming mice over intravenous treatment for 2 weeks.
The pharmacokinetic behavior of the main active component (oleic acid) was studied in SD rats. The pharmacodynamics of BJOL
was investigated using MMC-7721 cell lines and mice with Lewis lung cancer. The commercial emulsion of BJO (BJOE) was used
as a reference. The data showed that BJOL had an average diameter of 108.2 nm with a zeta potential of −57.0 mV, drug loading
of 3.60%, and entrapment efficiency of 92.40%. The area under curve of BJO in liposomes and emulsions were 2.31 and 1.15 mg min/ml,
respectively. Compared with BJOE, mean residence time and elimination half-time (t
1/2) increased 2.8- and 4.0-fold, respectively, and the clearance (CL) decreased 0.5-fold. In the acute toxicity test, the median
lethal dose (LD50) of BJOE was 7.35 g/kg. In contrast, all mice treated with liposomes survived even at the highest dosage (12.70 g/kg). The
IC50 value of BJOL group was one third of that of BJOE group (p < 0.01), and a less weight loss was observed in the BJOL-treated animals (p < 0.05). In conclusion, the present study suggests that BJOL significantly decreased toxicity of BJO and enhance the antitumor
activity. Therefore, liposomes may be a potential effective delivery vehicle for this lipophilic antitumor drug. 相似文献
157.
为探讨中国腹枝衣属地衣的物种多样性,进一步明确其分布特征与种类组成,该研究通过野外调查及采集地衣标本,结合形态、解剖、化学等方法,对128份采自中国热带及亚热带地区多个省份的腹枝衣属(Herpothallon)地衣标本进行了分类鉴定,共鉴定出腹枝衣属地衣12种,其中南方腹枝衣 [H. australasicum (Elix)Elix & G. Thor]、颗粒腹枝衣(H. granulosum Jagadeesh Ram & G. P. Sinha)、喜马拉雅腹枝衣(H. himalayanum Jagadeesh & G. P. Sinha)、裂芽腹枝衣(H. isidiatum Jagadeesh Ram & G. P. Sinha)和小腹枝衣(H. minutum Jagadeesh)为中国新记录种。并且对该属所有已知(已报道和本次鉴定)种类进行综合分析。结果表明:(1)中国已知腹枝衣属地衣14种,占世界已报道种类的29.17%。(2)地理成分有5种类型,即泛热带分布、热带亚洲至热带澳大利亚分布、热带亚洲和热带美洲间断分布、热带亚洲分布和中国特有分布。(3)中国腹枝衣属地衣主要分布在海拔300~2 500 m的范围内。(4)生长基物多为树皮,叶生、石生和藓生的物种较少。该研究结果表明,中国南方腹枝衣属地衣的物种多样性较高,这对明确中国该属地衣物种组成以及地衣多样性保护具有重要意义。 相似文献
158.
Jin Wang Kai-Jing Zuo Jie Qin Lida Zhang Lan Su Junrong Liu Hua Ling Jing-Ya Zhao You-Fang Cao Ke-Xuan Tang 《Acta Physiologiae Plantarum》2007,29(1):1-9
A novel cDNA clone encoding a COR413-like gene was isolated by suppression subtraction hybridization and cDNA library screening from sea-island cotton (Gossypium barbadense). This gene (designated as GbCOR413, Accession number: AY761065) has a total length of 893 bp with an open reading frame of 600 bp, encoding a predicated polypeptide
of 200 amino acids with a molecular weight of 22.74 kDa and a predicated pI of 9.2. Bioinformatics analyses revealed that this gene belonged to a novel stress-regulated multi-spanning transmembrane
protein family without signal peptide. By means of semi-quantities RT-PCR analysis, the expression of GbCOR413 under short-term cold treatment at 4°C, water submergence and abscic acid treatment was investigated. Our studies suggested
that the cloned gene was a new member of COR gene family which was slowly responsive to cold stress in cotton.
Jin Wang and Kai-Jing Zuo are co-first authors of this paper. 相似文献
159.
In this paper, a numerically detailed thermodynamic investigation of nucleosomal core particles is presented. The nonlinear Poisson-Boltzmann equation governs the electrostatic properties of both the DNA and histone protein. Brownian dynamics is used as the leading method, in combination with the analysis of the electrical features of the nucleosome. At elevated temperature, the structure of the nucleosome is destabilized by the decrease in electrical interactions of DNA-histone complexes, which can be explained with the EDL theory. Two obvious unwrapping transitions can be found, occurring within the temperature ranges 43-52 and 65-80 degrees C. The first transition is characterized by the melting of DNA terminal domains, and the feature of the second transition is the massive unwrapping of the DNA middle domain. It can be concluded that the nucleosomal DNA consists of two distinct structures, where the DNA terminal domains are less tightly bound to the histone than the DNA middle domain. 相似文献
160.
Shi L Bielawski J Mu J Dong H Teng C Zhang J Yang X Tomishige N Hanada K Hannun YA Zuo J 《Cell research》2007,17(12):1030-1040
Sphingolipids have been suggested to act as second messengers for an array of cellular signaling activities in plant cells, including stress responses and programmed cell death (PCD). However, the mechanisms underpinning these processes are not well understood. Here, we report that an Arabidopsis mutant, fumonisin B1 r_esistant11-1 (/br11-1), which fails to generate reactive oxygen intermediates (ROIs), is incapable of initiating PCD when the mutant is challenged by fumonisin B l (FB0, a specific inhibitor of ceramide synthase. Molecular analysis indicated that FBR11 encodes a long-chain base 1 (LCB 1) subunit of serine palmitoyltransferase (SPT), which catalyzes the first rate-limiting step of de novo sphingolipid synthesis. Mass spectrometric analysis of the sphingolipid concentrations revealed that whereas the fbr11-1 mutation did not affect basal levels of sphingoid bases, the mutant showed attenuated formation of sphingoid bases in response to FBl. By a direct feeding experiment, we show that the free sphingoid bases dihydrosphingosine, phytosphingosine and sphingosine efficiently induce ROI generation followed by cell death. Conversely, ROI generation and cell death induced by dihydrosphingosine were specifically blocked by its phosphorylated form dihydrosphingosine- 1-phosphate in a dosedependent manner, suggesting that the maintenance of homeostasis between a free sphingoid base and its phosphorylated derivative is critical to determining the cell fate. Because alterations of the sphingolipid level occur prior to the ROI production, we propose that the free sphingoid bases are involved in the control of PCD in Arabidopsis, presumably through the regulation of the ROI level upon receiving different developmental or environmental cues. 相似文献