144 resultados para 354
Resumo:
A series of amphiphilic polymers, monoesters of polymaleic acid containing ate-side groups (PMAN-A(n)Me) was synthesized by the reaction of alcohol(A,Me) with polymaleic anhydride (PMAN) for Langmuir-Blodgett assembly. The effects of the length of flexible spacer in the side chain on the pi-A isotherms and LB films were investigated. The UV-Vis and infrared linear dichroism spectra showed that the ate-side groups were highly oriented in PMAN-A(6)Me LB film deposited on silica or CaF2 substrate.
Resumo:
从花椰菜(Brasicaoleraceavar,botrytisL.)中提取、纯化植物钙调素(CaM),并通过激活辅酶I激酶及N(6氮基)5氯萘磺胺(W7)拮抗实验对其进行鉴定。通过内源荧光及三价铽发光确定了花椰菜钙调素中含有一个酪氨酸(Tyr)及4个金属结合位点,利用Frster型能量传递理论测量了Tyr→Ⅲ,Ⅳ位点之间距离分别为123nm及118nm,进一步通过Eu3+、Tb3+发光的结果说明植物钙调素与拮抗剂W7结合过程中,钙调素的构象发生了变化,但其金属配位环境基本无变化。
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采用新型稀土催化体系L_3-nLnX_n-R_3Al-R`X,研究了催化体系各组分、室温下再陈化时间、RX和R_3Al种类及用量、溶剂种类等因素对异戊二烯聚合的影响。在此基础上,经环化聚合合成出环化聚异戊二烯,并尝试了异戊二烯的立构嵌段聚合,用IR、NMR及动态力学测试等方法表征了聚合物的结构。合成出含1,4-结构68.2%含环化结构约28.9%,顺-1,4和反-1,4链段的Tg分别为-29℃和70℃的顺反立构嵌段聚异戊二烯。
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用NMR方法研究了氨三乙氧基乙酸(NTEA)的质子解离过程及其与La3+、Y3+、Lu3+和Ca2+的配合作用.NTEA的氮原子和羧基的质子解离常数分别为8.8和3.0.当pH>3.0时,La3+、Y3+和Lu3+配合物能稳定形成(>50%),而Ca2+配合物则需出>5.在pH3~6范围内,配合物与配体间的交换反应处于慢-中介交换速率区间,通过变温谱模拟得到了其交换反应的动力学参数.
Resumo:
在氯醚橡胶中加入7~10份强化交联剂三丙烯酸三羟甲基丙烷酯(TMPTA),置于2.7×10~6Bq钴-60辐射源中辐照,当吸收剂量为4.5×10~4GY时,可制得凝胶含量为66.4%的硫化胶。实验结果表明,在一定的吸收剂量下,凝胶含量、拉伸强度及扯断伸长平均随TMPTA用量的增加而增加;当吸收剂量增加时,凝胶含量、拉伸强度和扯断伸长率则下降,下降趋势随TMPTA用量的增加而逐渐减弱。
Resumo:
A phosphomolybdic anion doped polypyrrole (PMo12O403- + PPy) film electrode has been prepared by electrochemical polymerization of pyrrole in an aqueous solution of 0.5 mol l-1 H2SO4 or 0.5 mol l-1 KNO3 containing PMo12O403- anions, and characterized by scanning electron microscopy and in-situ UV-visible spectroelectrochemical methods. The film electrode obtained is very stable upon potential cycling in acidic solution, but not in neutral solution. The catalytic effect of the film electrode on the reduction of ClO3- and BrO3- was studied.
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稀土对生物体的作用首先是通过生物膜,因此研究稀土与生物膜的作用是阐明其生理过程的重要环节.~2H四极劈裂和稀土位移试剂两种方法的研究结果表明,二棕榈酸磷酯酰胆碱(DPPC)的极性基团在金属离子的作用下,由原来的平行于膜平
Resumo:
聚偏氟乙烯(PVF_2)是一种半结晶聚合物,它至少存在α、β、γ和δ四种晶相结构。其中β相由于其与PVF_2的压电性和热电性直接相关而引起人们的广泛关注。在以前的工作中,我们研究了超速淬火对PVP_2晶相结构的影响。本工作用傅里叶变换红外光谱(FTIR)技术研究了聚甲基丙烯酸甲酯(PMMA)分子构型对淬火过程中PVF_2β相生成温度的影响.
Resumo:
Serine proteases play critical roles in a variety of invertebrate immune defense responses, including hemolymph coagulation, antimicrobial peptide synthesis, and melanization. The first mollusk serine protease with clip-domain (designated CFSP1) cDNA was obtained from the scallop Chlamys farreri challenged with Vibrio anguillarum by randomly sequencing a whole tissue cDNA library and rapid amplification of cDNA ends (RACE). The full-length cDNA of the C. farreri serine protease was 1211 bp, consisting of a 5-terminal untranslated region (UTR) of 72 bp, a 3'-terminal UTR of 77 bp with a canonical polyadenylation signal sequence AATAAA and a poly (A) tail, and an open reading frame of 1062 bp. The CFSP1 cDNA encoded a polypeptide of 354 amino acids with a putative signal peptide of 19 amino acids and a mature protein of 335 amino acids. The deduced amino acid sequence of CFSP1 contained an amino-terminal clip domain, a low complexity region, and a carboxyl-terminal serine protease domain. CFSP1 mRNA was mainly expressed constitutively in the hemocytes and was up-regulated and increased 2.9- and 1.9-fold at 16 h after injury and injection of bacteria. (c) 2006 Elsevier Ltd. All rights reserved.
Resumo:
Serine proteinase homologues (SPHs), as one of prophenoloxiase-activating factors (PPAFs), play critical roles in innate immunity of crabs. Based on an EST from the eyestalk full length cDNA library, the complete cDNA (designated as PtSPH) and genomic DNA of SPH from the swimming crab Portunus trituberculatus were cloned in this study. The estimated molecular weight of mature PtSPH (354 amino acids) was 38.7 kDa and its isoelectric point was 5.08. Multiple sequence alignment revealed that PtSPH lacked a catalytic residue with a substitution of Ser in the active site triad to Gly. Phylogenetic analysis indicated PtSPH together with PPAFs of Callinectes sapidus (AAS60227), Eriocheir sinensis (ACU65942), Penaeus monodon (ABE03741, ACP19563) and Pacifastacus leniusculus (ACB41380), formed a distinct cluster which only included clip-SPHs. As the first analyzed genomic structure of PPAFs in crustaceans, two introns were found in the open reading frame region of this gene. The mRNA transcripts of PtSPH could be detected in all the examined tissues, and were higher expressed in the eyestalk than that in gill, hepatopancreas, haemocytes and muscle. Accompanied with the change in phenoloxidase (PO) activity and total haemocyte counts, the temporal expression of PtSPH gene in haemocytes after Vibrio alginolyticus challenge demonstrated a clear time-dependent expression pattern with two peaks within the experimental period of 32 h. These findings suggest that PtSPH is involved in the antibacterial defense mechanism of Portunus tritubercualtus crab. (C) 2010 Elsevier Ltd. All rights reserved.
Resumo:
藻胆蛋白是某些原核和真核藻类中一类重要的捕光天线蛋白,由脱辅基蛋白和开环四吡咯结构的色基共价结合组成。天然藻胆蛋白具有抗肿瘤、抗病毒、抗炎抗氧化等多种生物活性,而借助基因工程技术可以高效表达构效稳定的藻胆蛋白,应用于医药、食品、生化试剂等领域。 本研究在本实验室以前研制的抗肿瘤新药雷普克(rAPC)以及光学活性重组C-藻蓝蛋白α亚基的基础上,将别藻蓝蛋白α亚基基因apcA连入表达载体pCDFDuet-1中,构建了酶催化连接与自主催化连接两种新型载体,使大肠杆菌同时合成脱辅基蛋白与色基,而且二者能够在菌体内结合,表达出具有光学活性的重组别藻蓝蛋白α亚基。以重组菌BL21(DE3)作为研究对象,对酶催化连接的重组蛋白进行了5L规模的发酵,菌体密度OD600值达到23.52,并初步优化了发酵工艺,摸索了如何减少发酵过程中包涵体的生成。 采用金属螯合亲和层析的方法,建立了重组蛋白快速高效的纯化工艺。对比两种重组蛋白的光谱活性,发现藻蓝蛋白裂合酶的存在影响了重组蛋白的荧光吸收特性,推测藻胆蛋白的荧光特性可能是主要由脱辅基蛋白和色基空间构象决定,而不是肽链的一级结构。这些研究结果为解释藻胆蛋白荧光活性的机制提供了线索。
Resumo:
能量代谢指动物在进行生理活动(如摄食、消化以及动物的活动等)时所消耗能量的总和,一般以动物的呼吸率利排泄率来估计动物的能量代谢。其主要研究内容是闸明生物能量代谢的基木规律以及与环境闪子的关系。菲律宾蛤仔(Ruditapesphil ippmarum)是我国一种重要的养殖贝类,关于其能量代谢的研究却较少,这种状况妨碍了菲律宾蛤仔养殖生态理论的完善和养殖技术的提高。本研究主要对菲律宾蛤仔呼吸率和排泄率的基本规律(能量代谢与体重的关系、能量代谢的昼夜变化)及其与环境因子(饵料浓度、水温、栖息底质环境)的关系进行探讨。研究结果如下:1.不同体重菲律宾蛤仔代谢率小同。实验川菲律宾蛤仔分三种大小:l(干肉重为0.07-0.14g)、ll(干肉重0.27-0.34g)、III(干肉重0.45~0.63g)。温度包括:26℃(八月)、20℃(十月)、1 5℃(十二月)、9℃(一月)。实验共设四个饵料浓度:2.28±0.25,6.454±0.44,10.284±0.82,15.414±1.56mgTPM/L(TPM,总颗粒物),饵料中POM(颗粒有机物)含量都为4.68±1.64 mg/L。常温下菲律宾蛤仔代谢率随着体重的增大而增大。15℃、20~C、26℃时蛤仔呼吸率与干肉重呈明显的幂函数关系R=aW~b,a值变动范围为0.1076-0.3309;b值变动范围为0.239l~0.8381;蛤仔排泄率与干肉重也呈明显的幂函数关系N=aW~b,a值变动范围为14.213~68.362:b值变动范围为0.3673-1.1 532。9℃(饵料浓度为2.28±0.25mgTPM/L)、20℃(饵料浓度为10.284-0.82mgTPM/L)、26℃(饵料浓度为6.454±0.44mgTPM/L)时不同体重蛤仔氧氮比差异显著,其它情况下不同体重蛤仔氧氮比差异不显著。2.常温下菲律宾蛤仔代谢率受饵料浓度的影响,不同大小蛤仔受饵料浓度的影响程度不同。I组蛤仔呼吸率受饵料浓度的显著影响,II组III组蛤仔呼吸率只在9℃(一月)和26~C(八月)时受饵料浓度的显著影响。26℃时影响最显著,26℃时I组蛤仔在饵料浓度为2.28±0.25,6.45±0.44,l0.28±0.82,15.4l±1.56mgTPM/L时呼吸率分别是O.086,0.146,0.073,0.093(mlO_2/h);ll组蛤仔在上述浓度饵料中呼吸率分别是0.138,0.214,0.J 26,0.12l(mlO_2/h);III组蛤仔在上述浓度饵料中呼吸率分别是0.129,0.266,0.186,0.192(mlO_2/h)。菲律宾蛤仔呼吸率在饵料浓度为6.45±0.44 mgTPM/L时最高,蛤仔呼吸率在其它饵料浓度时都会降低。菲律宾蛤仔排泄率在饵料浓度为10.28±0.82 mgTPM/L和15.4l士1.56mgTPM/L时显著高于其它浓度组,9℃时这种趋势更明显,9℃时饵料浓度为2.28±0.25,6.454±044,lO.284±0.82,15.41±1.56mgTPM/L中I组蛤仔排泄率分别是4.297,2.874,8.003,6.658(μgNH_3-N/h);II组蛤仔在上述浓度饵料中排泄率分别是4.011,3.609,10.427,12.732(μgNH_3-N/h);III组蛤仔在上述浓度饵料中排泄率分别是2.28 l,6.452,10.283,15.417(μgNH_3-N/h)。3.菲律宾蛤仔代谢率受自然温度的显著影Ⅱ向。I组蛤仔在9℃、15℃、20℃、26℃时呼吸率平均为0.057,0.085,0.039,O.099;II组蛤仔在上述四个温度中呼吸率平均为0.08,O.128,0.089,0.149(mlO_2/h),I组和II组蛤仔在9℃和20~C时呼吸率较低,在26℃时呼吸率最高。III组蛤仔在上述四个温度中呼吸率平均为0.09,O.1 59,O.143,O.193(mlO_2/h),在9℃时llI组蛤仔呼吸率显著低于其它温度组。温度为9℃、15℃、20℃、26℃时l组蛤仔排泄率平均为5.458,13.169,4.946,11.138(μgNH_3-N/h):II组蛤仔在上述温度中排泄率平均为7.695,23.578,8.319,23.90l(μgNH_3-N/h);III组蛤仔在上述温度中排泄率平均为11.738,27.443,15.658,35.407(μgNH_3-N/h),蛤仔排泄率在15℃和26℃时均高于9℃和20℃。4.摄食状态与饥饿状态菲律宾蛤仔代谢率有明显不同。26℃时蛤仔静止状态呼吸率平均为0.336(m102/g干重.h),摄食状态呼吸率平均为0.656(ml0_2干重.h),摄食状态呼吸率比静止状态平均升高了0 32(ml0_2/g干重.h);26℃时蛤仔静止状态排泄率平均为39.471(μgNH_3-N/g干重.h),摄食状态排泄率平均为88.08(μgNH_3-N/g干重.h),摄食状态排泄率比静止状态排泄率平均升高了48.6(μgNH_3-N/g干重.h)。摄食状态代谢率平均是静止状态的2~3倍。根据摄食引起的呼吸率和排泄率升高量得出每氧化产生lμgNH_3-N需0_2量平均为7.05μl。5.人工控制温度对菲律宾蛤仔代谢率有明显影响。不同大小蛤仔受温度的影响程度不同。在温度5℃、10℃、l 5℃、20℃、26℃,I组和II组蛤仔呼吸率都随着温度的升高而升高,在10℃~l5℃和20℃~26℃这二个温度变化范围内呼吸率变化最大,在20℃~26℃时I组蛤仔呼吸率变动范围为O.85~1.04(m10_2/g干重.h)、II组蛤仔变动范围为0.57~0.86(ml0_2/g干重.h)。III组蛤仔呼吸率只在5℃~l0℃时明显增高,变动范围为0.09~0.5l(m10_2/g干重.h),在10℃~26℃范围内变化不大。I组和II组蛤仔排泄率随着温度的升高而升高,变动幅度较大,在5℃~26℃范围内其排泄率变动范围为10.32~81.53(μgNH_3-N/g干重.h);而 III组蛤仔排泄率只在5℃~15℃时随着温度的升高而升高,其排泄率变动范围为6.75~23.77(μgNH_3-N/g干重.h),在15℃~26℃范围内几乎不变。III组蛤仔的适温范围比I组和II组蛤仔广。菲律宾蛤仔在5℃和10℃时氧氮比变化明显,变动范围为2.76~11.44,在15~26℃时变化不大。6.菲律宾蛤仔代谢率有明显的日节律性,呈正弦曲线型变化。蛤仔夜问代谢率明显升高。I组蛤仔夜间呼吸率平均为0.867(m10_2/g干重.h),白天呼吸率平均为O.504(m10_2/g干重.h);II组蛤仔夜间呼吸率平均为0.438(m10_2/g干重.h),白天呼吸率平均为0.36l(m102/g干重.h);III组蛤仔夜间呼吸率平均为0.409(m10_2/g干重.h),白天呼吸率平均为0.252(m102/g干重.h)。在22:00-23:00菲律宾蛤仔呼吸率最高。7.底质环境对菲律宾蛤仔的代谢率有明显影响。在饥饿状态下菲律宾蛤仔在泥沙底质中呼吸率平均为l 406(m10_2/g干重h),在无泥沙环境中呼吸率平均为O.963(ml0_2/g干重.h);摄食状态下菲律宾蛤仔在泥沙底质中呼吸率平均为1.59l(m102/g干重.h),在无泥沙环境中呼吸率平均为1.115(m10_2/g干重.h)。在饥饿状态下菲律宾蛤仔在泥沙底质中排泄率平均为78.934(μgNH_3-N/g 干重.h),在无泥沙环境巾排泄率平均为45.043(μgNH_3-N/g干重.h);摄食状态下菲律宾蛤仔在泥沙底质中排泄率平均为87.12l(μgNH_3-N/g干重.h),在无泥沙底质中排泄率平均为58.354(μgNH_3-N/g干重.h)。蛤仔在泥沙环境中呼吸率和排泄率都明显升高。
Resumo:
Three kinds of Schiff bases of carboxymethyl chitosan (CMCTS) were prepared, and their antifungal activities were assessed according to Jasso de Rodriguez's method. The results indicated that 2-(2-hydroxybenzylideneamino)-6-carboxymethylchitosan (HNCMCTS) and 2-(5-chloro-2-hydroxybenzylideneamino)-6-carboxymethylchitosan (HCCMCTS) had better inhibitory effects than those of chitosan or CMCTS against Fusarium oxysporium f. sp. vasinfectum, Alternaria solani, and Valsa mali. (c) 2005 Elsevier Ltd. All rights reserved.
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对青海省民和、西宁和湟源3个地区的药用植物薄荷(Mentha haplocalyx Briq.)的净光合速率和叶绿素荧光参数的变化进行分析比较。结果显示:(1)最大净光合速率(P_n)湟源〉西宁〉民和;(2)PSⅡ反应中心最大光化学效率(F_v/F_m)以及PSⅡ反应中心活性参数(1/F_o-1/F_m)和实际光化学量子效率(Φ_(PSⅡ))的变化趋势相同,均以西宁最高,而相应的光合功能的相对限制(L_(PDF))西宁最低;(3)西宁薄荷的光化学猝灭系数(q_P)最高(0.875),而非光化学猝灭(NPQ)则最低(1.114)。研究表明,青海薄荷有光抑制现象发生,但并没有造成PSⅡ反应中心的不可逆破坏;西宁薄荷光化学能力较高而湟源薄荷对于过剩光能的耗散能力较高。
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报道了新疆赖草属2个新变种,即北疆赖草(Leymus tianschanicus(Drob.)Tzvel.var.borealus L.B.Cai)和短穗赖草(Leymus angustus(Trin.)Pilger vat.brevistachyus L.B.Cai)。