乌塘鳢对51Cr、60Co、131I、141Ce的吸收和积累

本文以河口底栖鱼类,不具鳞片,对环境适应力强的乌塘鳢为材料,研究它们以摄食和渗透两种方式对~(51)Cr,~(60)Co、~(131)I和~(141)Ce的吸收。为了观察在渗透吸收期间个体的差异,测定了单条活鱼的放射性。在实验中采用多核素示踪法并用S-80智能多道分析器和Ge(Li)探头测量放射性。 结果发现,当~(131)I的浓度为3.4×10~(-7)居里/升时,在10小时内所有的乌塘鳢都被杀死,而~(131)I在鱼体各组织器官的积累是明显的。器官积累核素数量的顺序是~(131)I>~(141)Ce>~(51)Cr,在任何组织器官均未检出~(60)Co。 在渗透吸收实验里,对单条活鱼的测量结果表明,核素是能够通过皮肤的渗透积累在鱼体内,并且存在个体差异。同时表明,生命元素的同位素如~(131)I,~(60)Co容易渗透到鱼体内部器官,而非生命元素的同位素例如~(141)Ce、~(51)Cr的渗透是慢的。 ~(51)Cr、~(60)Co、~(131)I、~(141)Ce是沿海核设施常见的放射性废物成分,有的是具有生态学意义的核素(Goldberg,1957),随着沿海核电站的不断兴建,它们在河口港湾存在的机会越来越多。虽然海洋鱼类和淡水鱼类对它们的浓集有过报道(Hiyama et al.,1964),但河口生物,特别是河口的底栖鱼类对它们的吸收和积累,则研究甚少。 乌塘鳢是生活在河口滩涂的底栖鱼类,适应于半咸淡的水质,     

Hormone (3-indoleacetic acid)-phospholipid interaction: 1H, 13C and 31P nuclear magnetic resonance studies

The interaction between the plant hormone, 3-indoleacetic acid (IAA), and some phospholipids in CDCL₃ has been studied by ¹H, ¹³C and ³¹P nuclear magnetic resonance (NMR) spectroscopy. Upon interaction with IAA, significant changes occurred in resonance positions of the phospholipid head group nuclei. Alteration of the fatty acid composition influenced the effects of IAA on these nuclei. These effects were observed in the ethanolamine and phosphate groups of the phosphatidylethanolamines, and in the choline, phosphate and glycerol groups of the phosphatidylcholines. Changes in resonance positions of the phospholipid head group nuclei were used for the determination of dissociation constants (K_d). In all cases, K_d values were approx. 10^?2 molal for 1 : 1 interaction. The NMR results suggest an interaction orientation in which the aromatic ring system of IAA interacts with the quaternary nitrogen function of the head group, and the phosphate group becomes hydrogen-bonded to the NH or carboxyl proton of 1AA.     

Identification of alpha adrenoceptor subtypes in dog arteries by (3H) yohimbine and (3H) prazosin

Binding of the alpha adrenergic antagonists (³H) prazosin and (³H) yohimbine to membranes of dog arteries exhibit the characteristics expected of alpha adrenoceptors. Binding of both ligands is saturable with dissociation constants of 0.19nM and 1.15nM for (³H) prazosin and (³H) yohimbine respectively. A series of catecholamines inhibit binding of both ligands with a potency in the order $\text{epinephrine}\text{>}\text{norepinephrine}\text{a}\text{?}\text{isoproterenol}$, corresponding with the activity of these agents at alpha adrenoceptors in blood vessels. Competition for binding in both instances is stereoselective. ?-Phenylephrine has similar potencies in inhibiting (³H) prazosin and (³H) yohimbine specific binding whilst the imidazoline related partial alpha adrenergic agonists clonidine and guanfacine are more potent in inhibiting (³H) yohimbine specific binding. The affinity of prazosin for the (³H) yohimbine binding site is approximately 2500 times less than for the (³H) prazosin site whilst yohimbine is approximately 150 times more potent in inhibiting (³H) yohimbine than (³H) prazosin specific binding. Non-selective alpha adrenergic antagonists have similar affinities for both binding sites. The concentrations of (³H) yohimbine binding sites in different arteries vary about two fold whilst for (³H) prazosin the variation was about three fold. These results indicate that there are two discrete noradrenergic binding sites in the major arteries of dog which have binding properties expected of alpha₁ and alpha₂ adrenoceptors.     

Comparative labelling of α1-acid glycoprotein by (3H)-borohydride or (125I)-iodide for use in a radioimmunoassay

The labelling of α₁-acid glycoprotein (AGP) with (³H)-sodium borohydride was compared to the labelling with (¹²⁵I)-sodium iodide by the chloramine T method in view to its use in a radioimmunoassay. The tritium labelling allowed to reach a high specific radioactivity similar to that obtained with iodide ((³H)-AGP: 29.8 mCi/mg; (¹²⁵I)-AGP: 30.5 mCi/mg). Each mole of sialic acid residue of AGP contains one atom of tritium. The stability of (³H)-AGP was better than that of (¹²⁵I)-AGP as indicated by its immunoreactivity as a function of time. Immunoreactivities and standard curves were similar for the two tracers but affinity of antiserum was higher for (¹²⁵I)-AGP than for (³H)-AGP. Tritium labelling by (³H)-borohydride will be very useful for glycoprotein antigens which cannot be labelled with (¹²⁵I)-iodide.     

A high-resolution NMR study (1H, 13C, 31P) of the interaction of paramagnetic ions with phospholipids in aqueous dispersions

¹H-, ¹³C-and ³¹P-NMR spectra of egg-yolk phosphatidylcholine (PC), phosphatidylserine (PS) and phosphatidic acid (PA) and cosonicated mixtures of these phospholipids were obtained from ultrasonicatcd dispersions containing Pr³⁺, Eu³⁺, Gd³⁺ and Mn²⁺ ions.The differences in chemical shift values. °_n, between the “inner” and “outer” resonance signals for the different nuclei of the polar head group of egg-yolk phosphatidyl choline provide information about the average distances of the paramagnetic ion within the polar groups of the phospholipid molecules. In the Pr(²H₂O)³⁺_n/egg-yolk phosphatidylcholine system the ions are nearest to the phosphate and -CH₂CH₂ group, respectively but relatively far from the N(CH₃)₃ group of the polar head group of the lipid.The integral analysis of the¹ H-NMR spectra obtained from dispersions containing Pr³⁺ and Mn²⁺ ions enables us to calculate the number of the polar groups in both sides of the egg-yolk phosphatidylcholine bilayer, the size of the lipid vesicle and to give some features of the arrangement of the phospholipid molecules in cosonicated egg-yolk phosphatidylcliotine/ phosphatidytserine vesicles. At p²H 8.3 in PC/PS mixtures an extreme asymmetry is observed with PS preferentially in the outer side of the membrane. This side contains approximately three times more PS than PC molecules.Some comments are made concerning the quantitative integral analysis of proton-noise decoupled ³¹ P-NMR spectra as obtained from similar phospholipid mixtures by Michaelson et al. and Berden et at.     

Reaction of PtOH complexes with CO2: synthesis and X-ray structure of (PBz3)4Pt2(Ph)2(η1,η1,μ-CO3)·(toluene)

The reaction of (diphoe)Pt(CH₂CN)(OH) and trans-(PBz₃)₂Pt(Ph)(OH) with CO₂ is reported as producing dimeric, bridged carbonato complexes of the type: P₄Pt₂(R)₂(CO₃). The crystal and molecular structure of (PBz₃)₄Pt₂(Ph)₂(μ-CO₃)·(toluene) is also reported, showing η¹, η¹ bonding. The reaction is recognized to proceed in a stepwise fashion through bicarbonato intermediates.     

胡杨愈伤组织质膜的两相分离法及其H＋-ATPase的特性

以胡杨愈伤组织为材料,用PEG 3350/DextranT 500构成的两相系统提取质膜微囊,研究质膜H+-ATPase的特性.结果显示由6.3% PEG 3350、6.3% Dextran T500、KCl、磷酸缓冲液(pH 7.8)和蔗糖构成的两相系统提取膜微囊的H+-ATPase活性分别被Na3VO4、KNO3、NaN3抑制了约75%、2.6%和1.3%.方向性检测显示原位膜微囊占提取质膜微囊的90%,翻转膜微囊仅占10%.去垢剂对质膜H+-ATPase活性的影响说明0.015%的Triton X-100和0.01%～0.1%的Brij 58适用于测定质膜H+-ATPase活性.Lineweaver-Burk动力学分析该酶的Km值为0.65 mmol*L-1,Vmax为37.59 μmol Pi*mg-1 protein*h-1.研究结果表明两相法提取的质膜微囊主要是正向密闭的膜微囊;胡杨愈伤组织质膜H+-ATPase的最适pH为6.5,最适温度为37℃左右.     

^60Co—γ射线对唐菖蒲染色体的影响

4组各16枚唐菖蒲种球分别经4Kγ、8kγ和15kγ剂量^60Co-γ射线照射后培养根尖,组织学制片,盐酸地衣红染色,光学显微镜观察。结果表明,与对照组相比,经过照射的样本细胞内具有染色体桥、核空泡化、落后染色体等染色体畸变现象,其中4kγ-8kγ剂量的^60Co-γ射线是较为适宜的唐菖蒲育种的照射剂量。     

融合蛋白M-IL-2(~(88)Arg,~(125)Ala)在毕赤酵母中的表达及抗肿瘤活性研究

构建融合基因蜂毒肽(melittin)与人变构白介素2(M-IL-2(88Arg,125Ala))毕赤酵母分泌型表达载体pPICZαA/M-IL-2(88Arg,125Ala),转化毕赤酵母菌株KM71H,甲醇诱导筛选出的多拷贝阳性菌株表达融合蛋白,纯化融合蛋白,并进行初步的抗肿瘤活性研究。经测序及PCR鉴定,M-IL-2(88Arg,125Ala)正确插入pPICZαA中,电转化后,重组载体通过同源重组整合到酵母基因组中,SDS-PAGE检测在26 ku左右有明显目的条带,与理论相符。经Western blot鉴定具有较高抗原性及特异性。BCA法测定甲醇诱导96 h融合蛋白表达量达315.2 mg/L。CCK-8法检测融合蛋白对人卵巢癌细胞SKOV3细胞及Hela细胞生长抑制作用,表明纯化的融合蛋白在体外能抑制人卵巢癌细胞SKOV3细胞及Hela细胞的生长增殖。该研究为融合蛋白M-IL-2(88Arg,125Ala)大规模制备和动物实验以及临床前期研究奠定了基础。     

The aerobic metabolism of 14C-sugars and 14CO2 by the daughter sporocysts of Microphallus similis (JÄG) and Macrophallus pygmaeus (Levinsen) (Digenea: Microphallidae)

The sporocysts of Microphallus similis and M. pygmaeus can aerobically utilise radiosugars and ¹⁴ CO₂in vitro. Both have an EMP pathway, TCA cycle, pentose-phosphate shunt, are able to undergo transamination reactions and can synthesise some essential amino acids. Carbon dioxide fixation involves the carboxylation of phosphoenolpyruvate to form oxaloacetate.     

A synthetic combination of mutations, including fs(1)pyr? Su(b) , r? Su(b) and b , causes female sterility and reduces embryonic viability in Drosophila melanogaster

A Drosophila melanogaster mutant, fs(1)pyr ^Su(b) , carrying a mutation that maps to the tip of the X chromosome, has been isolated. The mutation, when present alone, does not confer a detectable phenotype. However, this mutation causes female sterility and reduces embryonic viability when combined with mutations which deregulate the pyrimidine and β-alanine pools. Embryos that are homozygous for the mutations fs(1)pyr ^Su(b) , r ^Su(b) [previously designated as Su(b)] and b, and originate from a female parent homozygous for the three mutations show severely reduced viability. Newly laid eggs begin development normally, but the majority of the embryos die just before the eggs are due to hatch. Received: 15 May 1998 / Accepted: 18 January 1999     

Radiosynthesis and biological evaluation of 18F-labeled 4-anilinoquinazoline derivative (18F-FEA-Erlotinib) as a potential EGFR PET agent

Epidermal growth factor receptor (EGFR) has gained significant attention as a therapeutic target. Several EGFR targeting drugs (Gefitinib and Erlotinib) have been approved by US Food and Drug Administration (FDA) and have received high approval in clinical treatment. Nevertheless, the curative effect of these medicines varied in many solid tumors because of the different levels of expression and mutations of EGFR. Therefore, several PET radiotracers have been developed for the selective treatment of responsive patients who undergo PET/CT imaging for tyrosine kinase inhibitor (TKI) therapy. In this study, a novel fluorine-18 labeled 4-anilinoquinazoline based PET tracer, 1N-(3-(1-(2-¹⁸F-fluoroethyl)-1H-1,2,3-triazol-4-yl)phenyl)-6,7-bis(2-methoxyethoxy)quinazolin-4-amine (¹⁸F-FEA-Erlotinib), was synthesized and biological evaluation was performed in vitro and in vivo. ¹⁸F-FEA-Erlotinib was achieved within 50 min with over 88% radiochemical yield (decay corrected RCY), an average specific activity over 50 GBq/μmol, and over 99% radiochemical purity. In vitro stability study showed no decomposition of ¹⁸F-FEA-Erlotinib after incubated in PBS and FBS for 2 h. Cellular uptake and efflux experiment results indicated the specific binding of ¹⁸F-FEA-Erlotinib to HCC827 cell line with EGFR exon 19 deletions. In vivo, Biodistribution studies revealed that ¹⁸F-FEA-Erlotinib exhibited rapid blood clearance both through hepatobiliary and renal excretion. The tumor uptake of ¹⁸F-FEA-Erlotinib in HepG2, HCC827, and A431 tumor xenografts, with different EGFR expression and mutations, was visualized in PET images. Our results demonstrate the feasibility of using ¹⁸F-FEA-Erlotinib as a PET tracer for screening EGFR TKIs sensitive patients.     

The quasi-relativistic Xα-SW molecular orbital method in organo-f-element chemistry: applications to UCl4, (η5-C5H5)4U and (η5-C5H5)2UCl2

The advantages and disadvantages of using the Xα scattered-wave molecular orbital method with quasi-relativistic corrections for the calculation of the electronic structure of organo-f-element compounds is discussed. Application of the method in organouranium chemistry is discussed via comparative calculations on UCl₄, (η⁵-C₅H₅)₄U, and (η⁵-C₅H₅)₂UCl₂. It is found that the η⁵-C₅H₅^? ligand is a better donor to U than is Cl^? and that the valence orbitals of (η⁵-C₅H₅)₂UCl₂ are energetically closer to those of (η⁵-C₅H₅)₄U than UCl₄. The calculational results are in excellent accord with experimental photoelectron spectroscopic studies.     

Non-adiabatic electronic energy transfer from the (3CTRu(bpy)2(CN)2 excited state to Cr(III) complexes

The quenching of the luminescence lifetime of cis-Ru(bpy)₂(CN)₂ (bpy = 2,2′-bipyridine) by complexes of the cis- and trans-Cr(en)₂(XY)⁺ families (en = ethylenediamine; X and Y = F, Cl, Br, NCS, ONO) has been studied in aqueous solution and the results obtained have been discussed together with those previously reported for the quenching of the Ru(bpy)₃²⁺ luminescene by the same Cr(III) complexes. Experimental results and theoretical considerations show that the quenching process occurs by exchange electronic energy transfer. Since in all cases the process is sufficiently exoergonic to make up for the small intrinsic barriers, the lowest diffusion values of the quenching constants indicate a non-adiabatic behavior. The degree of adiabaticity of the energy transfer process is larger for the neutral Ru(bpy)₂(CN)₂ donor than for the positively charged Ru(bpy)₃²⁺ donor. The X and Y ligands can be ordered in the following adiabaticity series: ONO^?, F^? < Cl^? <NCS^? <Br^?. The geometry of the acceptor is a discriminating parameter only for energy transfer from the charged donor. These results show that the electronic term of exchange energy transfer in non-adiabatic processess is governed by a delicate balance of factors related to the composition and structure of the encounter complex [1].