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利用荧光光谱法、紫外光谱法、圆二色光谱法等方法研究了6-苄氨基嘌呤(6-BA)与牛血清白蛋白(BSA)之间的相互作用。结果表明,6-BA可以显著猝灭BSA的荧光,其猝灭机制为静态猝灭。6-BA与BSA的结合常数在293K、298 K和308 K时分别为2.4×104L.mol-1、2.6×104L.mol-1和3.1×104L.mol-1,两者之间存在一个结合位点。体系的焓变ΔH和熵变ΔS分别为14.2 kJ.mol-1和132.1 J.mol-1.K-1,说明6-BA与BSA之间主要以疏水作用力相互结合。根据F rster非辐射能量转移理论,6-BA与BSA间的结合距离为2.99 nm、能量转移效率为0.24。紫外光谱和圆二色光谱分析表明,6-BA可以导致BSA构象发生改变。 相似文献
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[目的]研究酰胺类除草剂(甲草胺、乙草胺)与牛血清白蛋白(BSA)的相互作用机制和作用类型。在模拟动物体生理条件下,应用荧光光谱法检测Stern-Volmer猝灭常数,用紫外分光光度法(UV)和圆二色光谱(CD)检测酰胺类除草剂对BSA构象的影响。[结果]用上述检测方法获得不同温度下酰胺类除草剂与BSA猝灭常数和热动力学常数,发现酰胺类除草剂对BSA有猝灭作用。[结论]静态猝灭是酰胺类除草剂导致BSA荧光猝灭的主要原因。不同温度下计算的热力学参数表明酰胺类除草剂与BSA之间的作用力主要是范德华力和氢键。加入酰胺类除草剂后导致BSA的构象发生变化。 相似文献
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在模拟动物体生理pH条件下,用荧光光谱法(FS)和电化学法研究了芦丁铕配合物(rutin-Eu)与人血清白蛋白(HSA)的结合反应.探讨了rutin-Eu对HSA的荧光猝灭过程的猝灭机理,以Lineweaver-Burk双倒数方程分别计算了不同温度下rutin-Eu与HSA的结合常数(KLB,295K:1.540×106L/mol,310K:1.265×106L/mol)、结合距离(r=2.28nm)和热力学参数(△Η=-9.97kJ/mol;295K:△S=84.64J/K,△G=-34.94kJ/mol;310K:△S=84.65J/K;△G=-36.21kJ/mol),并判断rutin-Eu与HSA结合的作用力类型;同时用圆二色谱及同步荧光光谱法探讨了rutin-Eu对HSA构象的影响.结果表明,rutin-Eu与HSA结合形成复合物,导致HSA内源性荧光猝灭是由于分子内的非辐射能量转移而引起的静态猝灭;它们之间的主要作用力是静电作用力而结合距离r为2.28nm.同步荧光光谱法和圆二色谱法表明rutin-Eu对HSA的构象有影响,可使HSA的二级结构发生改变. 相似文献
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在模拟人体生理条件下,利用荧光光谱法、圆二色谱法和三维荧光光谱法研究替加氟(TGF)与牛血清白蛋白(BSA)的相互作用。结果表明,替加氟使牛血清白蛋白的荧光强度发生了静态猝灭。根据修正的Stern-Vol mer方程,在292 K、298 K、304 K、310 K下,替加氟与牛血清白蛋白的有效猝灭常数分别为2.279×104L.mol-1、1.405×104L.mol-1、7.244×103L.mol-1和6.348×103L.mol-1。猝灭过程的ΔH和ΔS分别为-55.00 kJ.mol-1和-105.17 J.mol-1.K-1,表明范德华力和氢键是维持复合物TGF-BSA稳定的主要作用力。圆二色谱和三维荧光光谱分析发现,替加氟使牛血清白蛋白的α-螺旋结构含量减少,导致部分蛋白质肽链发生解旋,牛血清白蛋白分子的构象和所处的微环境发生了一定程度的变化。 相似文献
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《应用化工》2022,(3):645-650
通过熔融法以均苯四甲酸酐、尿素及相应的金属盐为原料,得到八羧基酞菁锰(MnOCPc)和八羧基酞菁铁(FeOCPc)。通过荧光光谱、紫外光谱、圆二色光谱等分析方法研究了金属酞菁与BSA的相互作用。结果表明,BSA的荧光发生了规律性的猝灭,其猝灭类型主要为静态猝灭。通过Stern-Volmer方程得到了两种金属酞菁对BSA的荧光猝灭常数和结合位点数等信息。圆二色光谱表明,金属酞菁使BSA的构象发生了变化,α-螺旋结构含量降低。抗氧化活性测试表明,金属酞菁、金属酞菁-BSA加合物均表现出一定的SOD活性,牛血清白蛋白的加入增强了金属酞菁的SOD活性。 相似文献
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光谱法研究迷迭香酸和牛血清白蛋白的相互作用 总被引:1,自引:0,他引:1
利用荧光和圆二色光谱研究了迷迭香酸(RA)与牛血清白蛋白(BSA)之间的相互作用.通过荧光猝灭测得在301、308和315 K时,RA与BSA的结合常数K分别为4.18×10~4、3.62×10~4和2.52×10~4 L/mol,表明RA与BSA间具有较强的结合作用,属于静态猝灭.热力学参数计算结果表明RA与BSA相互作用力以范德华力及氢键作用力为主.圆二色光谱、红外及拉曼光谱、荧光同步光谱研究表明相互作用后BSA的二级结构发生微小变化.此外,常见金属离子对结合有较为显著的影响. 相似文献
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M. S. J. Simmonds W. M. Blaney F. Delle Monache M. Marquina Mac-Quhae G. B. Marini Bettolo 《Journal of chemical ecology》1985,11(12):1593-1599
Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria. 相似文献
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Cheng-Le Zhao Shane Porzio Alan Smith Haiyan Ge H. T. Davis L. E. Scriven 《Journal of Coatings Technology and Research》2006,3(2):109-115
Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively.
There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized.
High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without
the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of
fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to
achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic
SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve
F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender
particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing,
and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing
or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually
preserves suspension stability during freezing.
Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago,
IL. Tied for first place in The John A. Gordon Best Paper Competition. 相似文献
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Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US
In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae
and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted
in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures
(release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species
(Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species
to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were
exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of
separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles
from the southeastern region of the US. 相似文献
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Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed. 相似文献
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中蓝晨光化工研究院有限公司《塑料工业》编辑部 《塑料工业》2009,37(3)
收集了2007年7月~2008年6月世界塑料工业的相关资料,介绍了2007~2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍. 相似文献
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中蓝晨光化工研究院《塑料工业》编辑部 《塑料工业》2007,35(3):1-25,67
收集了2005年7月~2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、通用热固性树脂(酚醛、聚氨酯、不饱和树脂、环氧树脂)、特种工程塑料(聚苯硫醚、液晶聚合物、聚醚醚酮)的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。 相似文献