毛细管电泳-激光诱导荧光分析血清多胺的研究

为进一步探讨多胺的生物学作用,建立了毛细管电泳-激光诱导荧光(λ_ex=488 nm,λ_em=513 nm)分析血清多胺方法.在碱性介质中,多胺与荧光素异硫氰酸酯进行衍生化反应,硼酸盐(pH 8.6)作为运行缓冲液,运行电压20 kV,腐胺、精胺、精脒和1,6-己二胺（内标）在8 min内达到基线分离.考察了方法的线性范围、稳定性、检测限和方法的回收率等,方法具有样品处理简单,灵敏度高,速度快等特点.用于正常对照大鼠和肿瘤大鼠血清多胺的测定.结果提示：实验组肿瘤大鼠血清精胺和精脒水平显著高于正常对照大鼠和实验组未出现肿瘤大鼠血清精胺和精脒水平（P＜0.05）,正常对照组大鼠和实验组未出现肿瘤大鼠血清精胺和精脒水平间无显著性差异（P＞0.05）,各组间血清腐胺水平均无显著性差异（P＞0.05）.     

多胺分析方法

<正> 多胺是腐胺、精脒、精胺的总称,与肿瘤关系甚密切。70年代初,Russell等报道了肿瘤病人尿液中多胺浓度增高,此后出现了不少对人体体液中多胺的分析方法,现综述如下:     

衰老大鼠的某些脑区多胺水平分析

着重探讨某些脑区非胍基多胺 (腐胺 ,精脒 ,精胺等 )与衰老关系 ,结果表明人工致衰老组和自然衰老组大鼠的纹状体、下丘脑、皮层以及小脑等脑区多胺水平较正常对照组均明显降低     

多胺调控细胞生长机制的研究进展

多胺(腐胺、精脒、精胺)是真核细胞体内重要的多聚阳离子,对细胞的生长增殖发挥重要作用。快速生长的细胞内含有高浓度的多胺,降低多胺含量将抑制细胞的生长,阻滞细胞周期,而升高多胺含量则会促进细胞快速生长增殖。对多胺的调控已经成为研究细胞生长增殖调控的切入点之一。     

精脒／精胺N^1-乙酰转移酶与肿瘤

多胺是人体中一类重要的含高密度正电荷的小分子有机化合物,肿瘤细胞快速生长对多胺的依赖使多胺代谢途径成为抗肿瘤治疗的新靶点。精脒／精胺N^1-乙酰转移酶（spermidine／spermine N^1-acetyltransferase,ssAT）是多胺降解代谢的限速酶,在维持细胞内多胺稳恒中发挥重要作用。研究发现,SSAT持续性高表达能促进肿瘤发生,而急性诱导性ssAT高表达则能抑制肿瘤生长和诱导肿瘤细胞凋亡。本文对近年来SSAT与肿瘤相关性最新研究进展进行简要综述。     

鸟氨酸脱羧酶抗酶抑制因子-1与细胞增殖

多胺(腐胺、精脒、精胺)参与细胞增殖、分化和凋亡等重要生命过程,细胞内多胺代谢紊乱也与包括肿瘤在内的多种疾病的发生发展密切相关。鸟氨酸脱羧酶抗酶抑制因子-1(antizyme inhibitor-1,AZIN1)是重要的多胺代谢调节蛋白,它通过多种途径调控细胞的生长。AZIN1能与鸟氨酸脱羧酶抗酶(antizyme,AZ)相互作用,解除后者对多胺合成限速酶鸟氨酸脱羧酶(ornithine decarboxylase,ODC)的抑制,由此上调细胞内多胺的含量。AZIN1还能通过调节细胞周期蛋白cyclin D1的降解速度和干扰细胞中心体复制而影响细胞增殖。AZIN1基因转录后修饰和某些特定mi RNA也对AZIN1的细胞增殖调节功能有重要影响。现对该研究领域的研究进展做简要综述。     

多胺在肿瘤研究中的意义

多胺（Ｐｏｌｙａｍｉｎｅ）是一类含二个或二个以上氨基的脂肪族化合物,它包括腐胺（Ｐｕｔｒｅｓｃｉｎｅ,Ｐｕｔ）、精脒（亚精胺）（Ｓｐｅｒｍｉｄｉｎｅ,Ｓｐｄ）、精胺（ｓｐｅｒｍｉｎｅｓｐｍ）。多胺来源于Ｌ－鸟氨酸;鸟氨酸脱羧酶（ＯｒｎｉｔｈｉｎｅＤｅｃａｒｂｏｘｙｌａｓｅ,ＯＤＣ）是多胺合成的限速酶。多胺与细胞的分裂分化、核酸代谢、蛋白质生物合成等有密切关系。细胞外液中浓度升高的多胺主要来源于肿瘤细胞。现已发现神经系统肿瘤、白血病、淋巴瘤、恶性黑色素瘤、肺癌、乳腺癌、消化系统肿瘤、泌尿生殖系统肿瘤病人体液中的多胺含量有不同程度的升高,作为恶性肿瘤辅助诊断、疗效及预后的制定,是一项较好的（临床诊断肿瘤）指标。多胺的分析方法、多胺合成抑制剂、鸟氨酸脱羧酶的调控机制及多胺与癌基因之间关系是值得进一步研究的新颖内容。     

多胺及其在植物体内的生理作用

多胺研究的历史及其在植物体内的分布多胺(polyamines)是一类广泛存在于原核生物及真核生物中的生物学活性物质,是一类低分子脂肪族含氮碱。常见的多胺(包括二胺)有腐胺(putrescine,put)H_2N(CH_2)_4NH_2、尸胺(cadaverine,cad)H_2N(CH_2)_5NH_2、亚精胺(spermidine,spd)H_2N(CH_2)_4NH(CH_2)_3NH_2和精胺(spermine,spm)H_2N(CH_2)_4NH(CH_2)_4NH(CH_2)_3NH_2。亚精胺又称精脒,是     

多胺在体外转录中的作用

多胺(包括精胺、精脒及腐胺等),广泛存在于动物、植物、微生物及病毒中。许多研究表明,多胺在生命过程中起重要作用。从分子生物学角度看,多胺对于DNA复制,基因表达的转录和翻译有重要的调节作用。不少人研究过多胺对DNA体外转录的调节作用,并企图了解它们影响转录的机理。本文试比较多胺对不同来源的RNA聚合酶进行体外转录的影响,以及用不同的RNA聚合酶转录不同构象的DNA模板时多胺的调节作用,以便     

多胺及其代谢产物对脑缺血的影响与治疗

多胺(Polyamines)是直链多价阳离子碱性胺,包括腐胺(putrescine,PUT),精胺(spermine,SPM),精脒(spermidine,SPD)等。广泛存在于各种组织细胞内,是一种代谢调控物质,在细胞的增殖分化中起着重要作用。脑梗死是成人致残、致死的最常见疾病之一。研究表明,脑缺血后,多胺及其代谢产物增加,能引起梗死面积的扩大及缺血半暗带神经细胞的坏死。其潜在机制尚不明确,可能与缺血后多胺代谢产生腐胺,3-氨基丙醛(3-amidopropanal 3-AP),过氧化氢及丙烯醛等的活性物质有关,它们参与开放钙离子通道,破坏血脑屏障,形成血管源性脑水肿及缺血再灌注性神经性损伤等病理过程。而抑制多胺代谢可有效地缓解缺血后多胺及其代谢产物增加引起的神经损伤。本文就多胺及代谢产物对脑缺血的神经毒性作用及药物抑制多胺代谢治疗脑梗死做一综述。     

Effects of acetylated polyamines on ornithine decarboxylase in rat HTC cells

N-Monoacetylputrescine and N⁸-monoacetylspermidine, metabolites of the naturally occurring polyamines, activate the enzyme ornithine decarboxylase (ODC). When added to cultures of hepatoma (HTC) cells growing in log phase, in concentrations of 5×10^?5M and 2.5×10^?7M respectively, these substances cause a 3 to 5-fold increase in the activity of ODC with a peak effect at one hour. This previously undescribed stimulating effect is in sharp contrast to the well established suppressing effects of nonacetylated polyamines on ODC activity.     

五种芳香类挥发物质对酪蝇的引诱效果

室内采用Y-型嗅觉仪测定不同浓度(1.0×10-6,1.0×10-5,1.0×10-4和1.0×10-3mL/mL)水杨醛、水杨酸甲酯、苯乙醛、苯甲醛、桂醇5种化合物对酪蝇Piophila casei(L.)成虫的引诱效果。结果表明:1.0×10-6和1.0×10-5mL/mL苯乙醛,1.0×10-6mL/mL苯甲醛,1.0×10-5和1.0×10-4mL/mL水杨醛均对雌、雄虫表现明显的引诱效果。1.0×10-3mL/mL苯乙醛、水杨醛和苯甲醛对酪蝇雌、雄虫具有明显的驱避效果。桂醇和水杨酸甲酯在所测试的浓度范围内对雄虫具有明显的驱避效果。水杨酸甲酯在浓度为1.0×10-6mL/mL对雌虫有明显的引诱效果,其它浓度均对雌虫有明显的驱避效果。桂醇对雌虫有明显的驱避效果。这表明在高浓度时芳香物质对酪蝇成虫有驱避效果,在低浓度时对酪蝇成虫有引诱效果。     

Biogenic and synthetic polyamines bind cationic dendrimers

Biogenic polyamines are essential for cell growth and differentiation, while polyamine analogues exert antitumor activity in multiple experimental model systems, including breast and lung cancer. Dendrimers are widely used for drug delivery in vitro and in vivo. We report the bindings of biogenic polyamines, spermine (spm), and spermidine (spmd), and their synthetic analogues, 3,7,11,15-tetrazaheptadecane.4HCl (BE-333) and 3,7,11,15,19-pentazahenicosane.5HCl (BE-3333) to dendrimers of different compositions, mPEG-PAMAM (G3), mPEG-PAMAM (G4) and PAMAM (G4). FTIR and UV-visible spectroscopic methods as well as molecular modeling were used to analyze polyamine binding mode, the binding constant and the effects of polyamine complexation on dendrimer stability and conformation. Structural analysis showed that polyamines bound dendrimers through both hydrophobic and hydrophilic contacts with overall binding constants of K(spm-mPEG-G3) = 7.6 × 10(4) M(-1), K(spm-mPEG-PAMAM-G4) = 4.6 × 10(4) M(-1), K(spm-PAMAM-G4) = 6.6 × 10(4) M(-1), K(spmd-mPEG-G3) = 1.0 × 10(5) M(-1), K(spmd-mPEG-PAMAM-G4) = 5.5 × 10(4) M(-1), K(spmd-PAMAM-G4) = 9.2 × 10(4) M(-1), K(BE-333-mPEG-G3) = 4.2 × 10(4) M(-1), K(Be-333-mPEG-PAMAM-G4) = 3.2 × 10(4) M(-1), K(BE-333-PAMAM-G4) = 3.6 × 10(4) M(-1), K(BE-3333-mPEG-G3) = 2.2 × 10(4) M(-1), K(Be-3333-mPEG-PAMAM-G4) = 2.4 × 10(4) M(-1), K(BE-3333-PAMAM-G4) = 2.3 × 10(4) M(-1). Biogenic polyamines showed stronger affinity toward dendrimers than those of synthetic polyamines, while weaker interaction was observed as polyamine cationic charges increased. The free binding energies calculated from docking studies were: -3.2 (spermine), -3.5 (spermidine) and -3.03 (BE-3333) kcal/mol, with the following order of binding affinity: spermidine-PAMAM-G-4>spermine-PAMMAM-G4>BE-3333-PAMAM-G4 consistent with spectroscopic data. Our results suggest that dendrimers can act as carrier vehicles for delivering antitumor polyamine analogues to target tissues.     

青藏高原生态系统服务功能的价值评估

青藏高原具有丰富多样的生态系统类型 ,这些生态系统不仅生产了大量的产品 ,而且提供了巨大的生态服务功能。根据计算表明 ,高原生态系统 2 0 0 0年生产的产品经济价值为 170× 10 8元。生态服务功能中年固碳总量为 15× 10 8t,释放氧气量为11× 10 8t。根据二氧化碳固定量和氧气释放量估算的调节大气的服务价值总计为 10 0 15× 10 8元。以高寒草甸和高寒草原为主的草地生态系统具有重要的水源涵养功能 ,每年高原生态系统的水源涵养量达 2 6 12× 10 8m3,其经济价值为 174 4× 10 8元。森林的净化功能价值大约为 2 5 5× 10 8元。高原生态系统产品的经济价值与生态服务功能价值的比值为 1:70 ,显然 ,高原生态系统的生态服务价值远远高于直接使用价值。因此 ,保护生态系统和生物多样性是维持生态系统稳定和保育高原生态过程的根本     

恶性转化的成纤维细胞表皮生长因子受体的研究

本文用受体的放射性配基结合分析方法观察了C_3H小鼠胚胎成纤维细胞C_3H_(10)T1/2 CL8(简称NC_3H_(10))和~3H-TdR恶性转化的C_3H_(10)T1/2CL8(简称TC_3H_(10))的表皮生长因子受体(EGFR)。结果表明细胞恶性转化前后的EGFR都存在高亲和力和低亲和力两种结合位点,细胞恶性转化后能结合表皮生长因子的EGFR结合位点减少,Western blotting和受体的亲和交联分析表明EGFR的分子量为170kD,是单链多肽。     

IgE-mediated 14C-serotonin release from rat mast cells modulated by morphine and endorphins

The formaldehyde method was used to examine the interaction of PGE₁ with morphine, β-endorphin and Met-enkephalin on rat mast cells by their effects on IgE-mediated ¹⁴C-serotonin release. PGE₁ (2×10^?8?2×10^?5 M) caused a dose-related inhibition of the mediator release 1 min after an antigen challenge, and morphine (3×10^?7?3×10^?5 M) reversed this PGE₁ effect dose-dependently and stereospecifically; naloxone (2×10^?4 M) antagonized this action of morphine. β-Endorphin (3×10^?7?10^?5 M) and Met-enkephalin (3×10^?6?10^?4 M) mimicked this morphine action dose-dependently and were antagonized by naloxone (2×10^?4 M). These results suggest that morphine and endorphins modulate immunological mediator release from rat mast cells through opioid receptors.     

猪心乳酸脱氢酶(H_4)在盐酸胍变性过程中失活与内源荧光变化速度的比较

本文比较了大然乳酸脱氢酶和硫酸铵稳定的乳酸脱氢酶在盐酸胍性过程式中失活与内源荧光的变化速度.酶失活表现为三相反应,即极快相,其速度常数用停流装置也无法测定;快相和慢相,1M胍变性时,此二相的一级反应速度常数分别为2.7×10~(-3)秒~(-1)和4.17×10~(-4)秒~(-1).在2M硫酸铵存在条件下,用2M胍更性时,快相和慢相的一极反应速度常数分别为6.16×10~(-3)秒~(-1)和1.88×10~(-3)秒~(-1).内源荧光强度的变化表现为二相反应,即极快相,相当酶失活的极快相,但变化幅度远小于酶失活的变化幅度;快相,相当于酶失活的快相,其速度常数为失活速度常数的1/3倍.上述结果表明,类似肌酸激酶,乳酸脱氢酶的失活速度快于酶分子整体构象的变化,相对于整个酶分子来说,活性中心的构象变化对变性剂更加敏感.     

一株球孢白僵菌的分离鉴定及其对草地贪夜蛾的致病性

草地贪夜蛾Spodoptera frugiperda(J. E.Smith)是我国于2019年新发现的一种迁飞性重大害虫。为了寻找对草地贪夜蛾有高致病性的昆虫病原真菌,本实验对采自广东省广州市华南农业大学湿地的感菌稻黑蝽Scotinophara lurida若虫僵虫进行了室内分离培养,结合形态学和rDNA-ITS序列分析,采用浸虫法研究了该菌对草地贪夜蛾各龄幼虫的致病力。鉴定结果表明该病原真菌为球孢白僵菌Beauveria bassiana,编号为GZSL-1菌株。菌株GZSL-1可侵染草地贪夜蛾6个龄期的幼虫,随孢子浓度的升高,草地贪夜蛾幼虫感病死亡率增加,当浓度达到1×10~8孢子/mL时,1～3龄幼虫的累计校正死亡率皆为100%,4龄和5龄幼虫也达到57.47%和55.06%,6龄仅25.28%。接菌6 d后1～5龄幼虫的LC_(50)值分别为1.32×10~3、3.42×10~3、1.01×10~4、1.61×10~5和1.23×10~7孢子/mL。幼虫LT_(50)值随孢子悬浮液浓度增加而递减,在孢子浓度为1.0×10~4～1.0×10~8孢子/mL范围内,1龄、2龄和3龄幼虫的LT_(50)值分别为3.58～1.69 d、4.30～1.78 d和5.70～3.12 d;浓度为1.0×10~5～1.0×10~8孢子/mL时,对4龄幼虫的LT_(50)为5.45～4.85 d;浓度为1.0×10~7～1.0×10~8孢子/mL时,对5龄幼虫的LT_(50)为5.04～5.02 d。上述研究结果表明,鉴定的球孢白僵菌菌株GZSL-1对草地贪夜蛾幼虫具有较强致病性,可为草地贪夜蛾微生物防治提供候选菌种资源。     

Molt-inhibiting hormone stimulates vitellogenesis at advanced ovarian developmental stages in the female blue crab, Callinectes sapidus 1: an ovarian stage dependent involvement

The finding that molt-inhibiting hormone (MIH) regulates vitellogenesis in the hepatopancreas of mature Callinectes sapidus females, raised the need for the characterization of its mode of action. Using classical radioligand binding assays, we located specific, saturable, and non-cooperative binding sites for MIH in the Y-organs of juveniles (J-YO) and in the hepatopancreas of vitellogenic adult females. MIH binding to the hepatopancreas membranes had an affinity 77 times lower than that of juvenile YO membranes (K_D values: 3.22 × 10^-8 and 4.19 × 10^-10 M/mg protein, respectively). The number of maximum binding sites (B_MAX) was approximately two times higher in the hepatopancreas than in the YO (B_MAX values: 9.24 × 10^-9 and 4.8 × 10^-9 M/mg protein, respectively). Furthermore, MIH binding site number in the hepatopancreas was dependent on ovarian stage and was twice as high at stage 3 than at stages 2 and 1. SDS-PAGE separation of [¹²⁵I] MIH or [¹²⁵I] crustacean hyperglycemic hormone (CHH) crosslinked to the specific binding sites in the membranes of the J-YO and hepatopancreas suggests a molecular weight of ~51 kDa for a MIH receptor in both tissues and a molecular weight of ~61 kDa for a CHH receptor in the hepatopancreas. The use of an in vitro incubation of hepatopancreas fragments suggests that MIH probably utilizes cAMP as a second messenger in this tissue, as cAMP levels increased in response to MIH. Additionally, 8-Bromo-cAMP mimicked the effects of MIH on vitellogenin (VtG) mRNA and heterogeneous nuclear (hn) VtG RNA levels. The results imply that the functions of MIH in the regulation of molt and vitellogenesis are mediated through tissue specific receptors with different kinetics and signal transduction. MIH ability to regulate vitellogenesis is associated with the appearance of MIH specific membrane binding sites in the hepatopancreas upon pubertal/final molt.     

Analysis of polyamines in biological samples by HPLC involving pre-column derivatization with o-phthalaldehyde and N-acetyl-l-cysteine

Polyamines (putrescine, spermine and spermidine) play a crucial role in the regulation of cell growth, differentiation, death and function. Accurate measurement of these substances is essential for studying their metabolism in cells. This protocol describes detailed procedures for sample preparation and HPLC analysis of polyamines and related molecules (e.g., agmatine and cadaverine) in biological samples. The method is optimized for the deproteinization of samples, including biological fluids (e.g., 10 μl), plant and animal tissues (e.g., 50 mg), and isolated/cultured cells (e.g., 1 × 10⁶ cells). The in-line reaction of polyamines with o-phthalaldehyde and N-acetyl-l-cysteine yields fluorescent derivatives which are separated on a reversed-phase C₁₈ column and detected by a fluorometer at an excitation wavelength of 340 nm and an emission wavelength of 450 nm. The total running time for each sample (including column regeneration on the automated system) is 30 min. The detection limit is 0.5 nmol/ml or 0.1 nmol/mg tissue in biological samples. The assays are linear between 1 and 50 μM for each of the polyamines. The accuracy (the nearness of an experimental value to the true value) and precision (agreement between replicate measurement) of the HPLC method are 2.5–4.2 % and 0.5–1.4 %, respectively, for biological samples, depending on polyamine concentrations and sample type. Our HPLC method is highly sensitive, specific, accurate, easily automated, and capable for the analysis of samples with different characteristics and small volume/amount, and provides a useful research tool for studying the biochemistry, physiology, and pharmacology of polyamines and related substances.