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991.
A new type of sol-gel-derived titanium oxide/copolymer composite material was developed and used for the construction of glucose biosensor. The composite material merged the best properties of the inorganic species, titanium oxide and the organic copolymer, poly(vinyl alcohol) grafting 4-vinylpyridine (PVA-g-PVP). The glucose oxidase entrapped in the composite matrix retained its bioactivity. Morphologies of the composite-modified electrode and the enzyme electrode were characterized with a scanning electron microscope. The dependence of the current responses on enzyme-loading and pH was studied. The response time of the biosensor was < 20 s and the linear range was up to 9 microM with a sensitivity of 405 nA/microM. The biosensor was stable for at least 1 month. In addition, the tetrathiafulvalene-mediated enzyme electrode was constructed for the decrease of detection potential and the effect of three common physiological sources that might interfere was also investigated. 相似文献
992.
993.
A suppression subtractive hybridization cDNA library was used to screen the differently expressed (up-regulated) genes in the photosynthesis–fermentation approach (PFA) of Chlorella protothecoides cultivation. A total of 87 clones were obtained and sequenced, in which 78 clones were homologous to known genes in databases. Among them, the ammonium transporter gene (CpAMT1) was characterized in detail. Quantitative real-time PCR showed that the expression of CpAMT1 was significantly induced by PFA and correlated with lipid accumulation. The up-regulation of CpAMT1 was suppressed by glutamine, while the lipid biosynthesis was also inhibited. Further analysis showed that the expression of CpAMT1 was correlated with glutamine synthetase activity, suggesting that CpAMT1, along with glutamine synthetase/glutamate synthase, may be responsible for nitrogen sensing in C. protothecoides. Together, these results imply that the ammonium transporter CpAMT1 could be the initial sensor of nitrogen deficiency and channels the carbon excess toward lipid biosynthesis. 相似文献
994.
Byoung-Shik Shim Jung-ah Choi Ho-Hyun Song Sung-Moo Park In Su Cheon Ji-Eun Jang Sun Je Woo Chung Hwan Cho Min-Suk Song Hyemi Kim Kyung Joo Song Jae Myun Lee Suhng Wook Kim Dae Sub Song Young Ki Choi Jae-Ouk Kim Huan Huu Nguyen Dong Wook Kim Young Yil Bahk Cheol-Heui Yun Man Ki Song 《Journal of microbiology (Seoul, Korea)》2013,51(1):130-135
Influenza viruses are respiratory pathogens that continue to pose a significantly high risk of morbidity and mortality of humans worldwide. Vaccination is one of the most effective strategies for minimizing damages by influenza outbreaks. In addition, rapid development and production of efficient vaccine with convenient administration is required in case of influenza pandemic. In this study, we generated recombinant influenza virus hemagglutinin protein 1 (sHA1) of 2009 pandemic influenza virus as a vaccine candidate using a well-established bacterial expression system and administered it into mice via sublingual (s.l.) route. We found that s.l. immunization with the recombinant sHA1 plus cholera toxin (CT) induced mucosal antibodies as well as systemic antibodies including neutralizing Abs and provided complete protection against infection with pandemic influenza virus A/CA/04/09 (H1N1) in mice. Indeed, the protection efficacy was comparable with that induced by intramuscular (i.m.) immunization route utilized as general administration route of influenza vaccine. These results suggest that s.l. vaccination with the recombinant non-glycosylated HA1 protein offers an alternative strategy to control influenza outbreaks including pandemics. 相似文献
995.
Yan Ding Hua Yang Jing Bo Feng Ying Qiu Dong Sheng Li Yi Zeng 《In vitro cellular & developmental biology. Animal》2013,49(10):771-777
Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) hold great potential for their therapeutic use in various clinical diseases. Many publications have reported on human blood-derived alternatives to animal serum for culturing mesenchymal stem cells, such as human serum, allogenic umbilical cord blood serum, and human platelet derivatives. However, it is not clear whether human umbilical cord blood plasma (UCBP), as the surplusage of umbilical cord blood mesenchymal stem cell extraction, could be used. In this study, in order to make the best of umbilical cord blood, the human UCBP was dialyzed to replace fetal bovine serum (FBS) in the culture medium. hUC-MSCs were cultured in the new medium. Cell growth rate, specific biomarkers, and differentiation properties were detected to characterize the cell proliferation and MSC-specific properties. The hUC-MSCs cultured in such derived medium were verified with proliferation rate, cluster differentiation markers, cell cycle, as well as differentiation capabilities. Such dialyzed human UCBP is fully comparable with, if not superior to, FBS in deriving and culturing hUC-MSCs. 相似文献
996.
Linyan Zhu Wanhong Zuo Haifeng Yang Haifeng Zhang Hai Luo Dong Ye Xi Lin Jianwen Mao Jianqiang Feng Lixin Chen Liwei Wang 《Molecular neurobiology》2013,48(1):205-216
The functions of chloride channels in preconditioning-induced cell protection remain unclear. In this report, we show that the volume-activated chloride channels play a key role in hydrogen peroxide (H2O2) preconditioning-induced cell protection in pheochromocytoma PC12 cells. The preconditioning with 100 μM H2O2 for 90 min protected the cells from injury induced by long period exposure to 300 μM H2O2. The protective effect was attenuated by pretreatment with the chloride channel blockers, 5-nitro-2-3-phenylpropylamino benzoic acid (NPPB) and tamoxifen. H2O2 preconditioning directly activated a chloride current, which was moderately outward-rectified and sensitive to the chloride channel blockers and hypertonicity-induced cell shrinkage. H2O2 preconditioning functionally up-regulated the activities of volume-activated chloride channels and enhanced the regulatory volume decrease when exposure to extracellular hypotonic challenges. In addition, acute application of H2O2 showed distinctive actions on cell volume and membrane permeability in H2O2 preconditioned cells. In H2O2 preconditioned cells, acute application of 300 μM H2O2 first promptly induced a decrease of cell volume and enhancement of cell membrane permeability, and then, cell volume was maintained at a relatively stable level and the facilitation of membrane permeability was reduced. Conversely, in control cells, 300 μM H2O2 induced a slow but persistent apoptotic volume decrease (AVD) and facilitation of membrane permeability. H2O2 preconditioning also significantly up-regulated the expression of ClC-3 protein, the molecular candidate of the volume-activated chloride channel. These results suggest that H2O2 preconditioning can enhance the expression and functional activities of volume-activated chloride channels, thereby modulate cell volume and cell membrane permeability, which may contribute to neuroprotection against oxidant-induced injury. 相似文献
997.
大肠杆菌tyrR基因剔除及其对苯丙氨酸生物合成的影响 总被引:1,自引:0,他引:1
TyrR是大肠杆菌芳香族氨基酸生物合成和运输途径中的一种全局性调控蛋白质。采用双交换同源重组的方法定位突变大肠杆菌染色体tyrR基因 ,在该基因中插入带有卡那霉素抗性基因的DNA片段 ,使之失活 ,实现基因剔除。经PCR、DNA测序、lacZ报告基因等多种方法证实了基因剔除的可靠性。tyrR基因剔除后 ,大肠杆菌芳香族氨基酸生物合成中受TyrR蛋白调控的关键酶的酶活力有所提高 :3 脱氧 2 阿拉伯庚酮糖 7 磷酸合成酶(DAHPS ,由aroG编码 )酶活力提高了 1.0 8倍 ,转氨酶 (AT ,由tyrB编码 )酶活力提高了 2 .70倍 ;突变菌株发酵生产苯丙氨酸的能力提高了 1.5 9倍 ;同时 ,与芳香族氨基酸运输相关的通透酶基因aroP(P)的阻遏被解除 ,细胞运输芳香族氨基酸的能力提高了 70 .2 %。 相似文献
998.
McGuinness MC Lu JF Zhang HP Dong GX Heinzer AK Watkins PA Powers J Smith KD 《Molecular and cellular biology》2003,23(2):744-753
Peroxisomal disorders have been associated with malfunction of peroxisomal metabolic pathways, but the pathogenesis of these disorders is largely unknown. X-linked adrenoleukodystrophy (X-ALD) is associated with elevated levels of very-long-chain fatty acids (VLCFA; C(>22:0)) that have been attributed to reduced peroxisomal VLCFA beta-oxidation activity. Previously, our laboratory and others have reported elevated VLCFA levels and reduced peroxisomal VLCFA beta-oxidation in human and mouse X-ALD fibroblasts. In this study, we found normal levels of peroxisomal VLCFA beta-oxidation in tissues from ALD mice with elevated VLCFA levels. Treatment of ALD mice with pharmacological agents resulted in decreased VLCFA levels without a change in VLCFA beta-oxidation activity. These data indicate that ALDP does not determine the rate of VLCFA beta-oxidation and that VLCFA levels are not determined by the rate of VLCFA beta-oxidation. The rate of peroxisomal VLCFA beta-oxidation in human and mouse fibroblasts in vitro is affected by the rate of mitochondrial long-chain fatty acid beta-oxidation. We hypothesize that ALDP facilitates the interaction between peroxisomes and mitochondria, resulting, when ALDP is deficient in X-ALD, in increased VLCFA accumulation despite normal peroxisomal VLCFA beta-oxidation in ALD mouse tissues. In support of this hypothesis, mitochondrial structural abnormalities were observed in adrenal cortical cells of ALD mice. 相似文献
999.
Interacting genetic loci on chromosomes 20 and 10 influence extreme human obesity 总被引:6,自引:0,他引:6 下载免费PDF全文
Obesity is a multigenic trait that has a substantial genetic component. Animal models confirm a role for gene-gene interactions, and human studies suggest that as much as one-third of the heritable variance may be due to nonadditive gene effects. To evaluate potential epistatic interactions among five regions, on chromosomes 7, 10, and 20, that have previously been linked to obesity phenotypes, we conducted pairwise correlation analyses based on alleles shared identical by descent (IBD) for independent obese affected sibling pairs (ASPs), and we determined family-specific nonparametric linkage (NPL) scores in 244 families. The correlation analyses were also conducted separately, by race, through use of race-specific allele frequencies. Conditional analyses for a qualitative trait (body mass index [BMI] >/=27) and hierarchical models for quantitative traits were used to further refine evidence of gene interaction. Both the ASP-specific IBD-sharing probability and the family-specific NPL score revealed that there were strong positive correlations between 10q (88-97 cM) and 20q (65-83 cM), through single-point and multipoint analyses with three obesity thresholds (BMI >/=27, >/=30, and >/=35) across African American and European American samples. Conditional analyses for BMI >/=27 found that the LOD score at 20q rises from 1.53 in the baseline analysis to 2.80 (empirical P=.012) when families were weighted by evidence for linkage at 10q (D10S1646) through use of zero-one weights (weight(0-1)) and to 3.32 (empirical P<.001) when proportional weights (weight(prop)) were used. For percentage fat mass, variance-component analysis based on a two-locus epistatic model yielded significant evidence for interaction between 20q (75 cM) and the chromosome 10 centromere (LOD = 1.74; P=.024), compared with a two-locus additive model (LOD = 0.90). The results from multiple methods and correlated phenotypes are consistent in suggesting that epistatic interactions between loci in these regions play a role in extreme human obesity. 相似文献
1000.
目的通过建立一个适应于尖吻蝮仔蛇生长发育的稳定的多功能生态系统的人工模拟生态养殖蛇场,以最大限度地降低仔蛇的饲料成本,从而达到降低人工养殖尖吻蝮蛇的成本。方法选取一个室外围墙式养蛇场作为试验基地。设计为适应于蛇、蛙、昆虫、蚯蚓、小杂鱼等动物生长繁衍的人工模拟生态环境,建立一个稳定的多功能蛇场生态系统,以尖吻蝮蛇100条,在试验以前随机抽取10条测量其体重和体长,并以活体动物饲料喂养法和科学饲养管理法进行试验养殖,并在进入第一、第二次冬眠前均随机抽取10条蛇仔测其体重和体长。结果本次试验与本蛇场室内人工饲养尖吻蝮仔蛇相比,不仅在体重、体长和肥满度方面均相差不大,而且仔蛇的存活率还有所提高。结论表明该人工模拟生态养殖蛇场能够满足尖吻蝮仔蛇生长发育的需要,达到了预期的目的。 相似文献