芹菜素镧配合物的结构表征及生物活性研究

以芹菜素和硝酸镧为原料首次合成芹菜素镧配合物,通过元素分析、摩尔电导、红外光谱、热差分析、核磁共振氢谱来分析测定配合物的组成和结构,并对配合物进行了清除超氧自由基(O-·2)和羟自由基(·OH)的研究以及对宫颈癌细胞Hela的抗肿瘤活性的研究。结果表明,配合物组成为:La(C15H9O5)2NO3·1.5H2O,其具有较强的抗氧化活性和抗宫颈癌细胞Hela活性。     

黄芩苷镧(Ⅲ)、钇(Ⅲ)配合物的合成及生物活性研究

改进以往反应条件,合成了黄芩苷镧(Ⅲ)、黄芩苷钇(Ⅲ)配合物,利用IR、UV、LC-MS和金属元素含量测定对配合物进行了表征。采用MTT法分别考察了两种新化合物的抑菌活性(金黄色葡萄球菌、大肠杆菌、枯草芽孢杆菌、沙门氏菌、白色念珠菌)和抗肿瘤活性(A549、HepG2),采用灌胃法考察化合物对小鼠的急性毒性。结果表明:黄芩苷在与金属配合后,结构表征发生了一定的变化,配合物无金属离子毒性反应,并且其抑菌、抗肿瘤作用均显示出黄芩苷镧>黄芩苷钇>黄芩苷。     

桂皮酸-镧(Ⅲ)配合物与鲱鱼精DNA的相互作用

制备了桂皮酸-镧(III)配合物,通过紫外-可见光谱法研究了桂皮酸与La(III)的相互作用,发现La(III)与桂皮酸可形成1∶2的配合物,该配合物的摩尔吸光系数ε=4.9×106L/(mol·cm)。此外,采用紫外吸收光谱、荧光光谱和粘度法,研究了配合物与鲱鱼精DNA之间的相互作用。结果显示配合物与DNA作用的结合常数K=4.47×103L/mol,DNA与配合物的作用摩尔比为1∶3,作用模式为插入作用。     

稀土对肌质网Ca~（2＋）－ATP酶活性的影响

研究了镧、轧、镱及四种配合物对Ｃａ~（２＋）－ＡＴＰ酶活性的影响．结果表明,低浓度的Ｌａ~（３＋）,Ｇｄ~（３＋）和Ｙｂ~（３＋）对肌质网Ｃａ~（２＋）－ＡＴＰ酶有激活作用;随着其浓度的增加,它们对酶活性的抑制程度增大;而Ｌａ~（３＋）,Ｇｄ~（３＋）和Ｙｂ~（３＋）对纯化的Ｃａ２~（＋）－ＡＴＰ酶则只有抑制作用;Ｇｄ─Ｎ─乙酰─缬氨酸和Ｙｂ─丙氨酰代丙氨酸配合物对肌质网膜和纯化的Ｃａ~（２＋）－ＡＴＰ酶活性的影响与Ｇｄ~（３＋）及Ｙｂ~（３＋）类似,但其激活程度和抑制程度比Ｇｄ~（３＋）及Ｙｂ~（３＋）小;Ｇｄ─ＤＴＰＡ和Ｙｂ－ＤＴＰＡ对Ｃａ２~（＋）－ＡＴＰ酶活性基本无影响。     

农田生态条件下玉米秸秆腐解过程腐解物的热解变化特征

用热分析法研究了农田生态条件下玉米秸杆腐解过程腐解物的热解变化特征,并探讨了腐解物中不同组分对腐解物热解特征的影响。结果表明,腐解物ＤＴＡ曲线的２８０℃、３３０℃、４５０℃放热峰,ＤＴＧ曲线的第二失重峰和ｈ３３０℃／ｈ４５０℃值可作为表征腐解进程的特征峰和特征值。由腐解特ＤＴＡ、ＤＴＧ所得能量各参数（△Ｈ,Ｅ）与文献「３」所述腐解物能态（Ｑｖ）呈现波动起伏,趋于稳定２个阶段相符,二者相互印证,显示     

枯落物分解及其影响因素

本文从枯落物分解的阶段划分到分解过程中的质量损失、组分变化、性质转变等方面详细讨论了枯落物分解过程、特征及影响因素。枯落物分解主要包括物理淋溶、生物化学分解和破碎过程,其中物理淋溶和生物化学分解分别在分解前期和后期占据主导地位。枯落物分解过程具有阶段性和特征连续性,且普遍按照先快后慢的规律发生质量损失。难分解的物质逐渐累积,导致枯落物腐殖化程度增强,芳香性和吸附性增加,生物可降解性降低。枯落物分解过程营养元素变化多元化,C含量普遍下降,N和P则受各种因素影响或累积或释放。枯落物分解是多重因子综合作用的过程,其中枯落物性质是本质要素,而温度、水分、土壤生物群落等均对枯落物分解产生不同程度的影响。水分的增加可以加快淋溶从而促进枯落物分解,温度的增加在一定程度上可以增强微生物活性;土壤生物对枯落物分解有明显贡献,其中微生物在枯落物分解中占主导地位,土壤动物起到一定的辅助作用。在此基础上,提出枯落物分解机理、影响因子之间的交互作用、枯落物分解对生态变化的反馈等将是未来枯落物分解研究的重点。     

树下丘脑视交叉上核突触超微结构的电镜观察

本研究借助免疫电镜和溃变纤维电镜追踪等技术,探索我国南方特产,昼行动物“灵长类原宗”树鼠句（ＴＢＣ）下丘脑视交叉上核（ＳＣＮ）的突触,特别是ＳＣＮ中５－羟色胺（５－ＨＴ）能和视纤维传入的突触联系的超微结构特征,结果表明：ＴＢＣ的ＳＣＮ主要包含不对称性ＧｒａｙⅠ型（ＧＴⅠ）和对称性ＧｒａｙⅡ型（ＧＴⅡ）两种突触类型。其中ＧＴⅠ突触的后膜下颇多呈现“三体一线”的节下小体。５－ＨＴ能末梢在ＴＢＣ的ＳＣＮ（主要在其腹侧）中形成丰富的ＧＴⅠ和ＧＴⅡ突触。还观察到ＳＣＮ中５－ＨＴ能末梢和非５－ＨＴ能轴突构成颇多的轴－轴突触,５－ＨＴ能末梢既可为突触前也可为突触后成分。这在大鼠ＳＣＮ中未见报道,而视纤维传入在ＳＣＮ腹外侧区主要形成ＧＴⅠ突触     

盐度对互花米草枯落物分解释放硅、碳、氮元素的影响

为了研究潮汐湿地盐度对枯落物分解过程中硅、碳、氮元素释放的影响,通过室内模拟不同盐度(0、5、15和30)对互花米草枯落物茎和叶分解释放过程中硅、碳、氮元素的动态变化进行测定。结果表明:(1)互花米草茎和叶枯落物失重率和分解速率均随盐度增加而降低。(2)互花米草茎和叶枯落物分解水体中硅含量均随着盐度升高而增加,并且盐度30处理下,枯落物分解硅释放量显著高于盐度0和5(P0.05)。而分解末期生物硅残留量则随盐度升高而降低。(3)不同盐度处理茎枯落物分解碳释放量无显著差异,但叶枯落物分解碳释放量在盐度5、15和30处理中显著高于淡水(P0.05)。(4)互花米草茎枯落物分解释放到水中的NH_4~+-N含量随着盐度的升高而减少,NO_3~--N含量与之相反。研究单因素盐度对枯落物分解及元素释放的影响,可以为预测潮汐湿地枯落物分解对盐水入侵的响应机制提供参考,为湿地生源要素生物地球化学循环过程研究提供基础依据。     

植物激素与营养液配施对平菇产量和品质的影响

不同配比的ＧＡ＿３和ＫＴ与营养液配施,对平菇菌丝生长影响不同。ＧＡ＿３和ＫＴ的适当配比,能促进菌丝分枝生长,也能显著提高平菇子实体的产量和品质,但维生素Ｃ的含量有所下降。ＧＡ＿３和ＫＴ若与营养液配合施用,比单独施用更能发挥其促进作用。     

陆地生态系统混合凋落物分解研究进展

凋落物分解在陆地生态系统养分循环与能量流动中具有重要作用,是碳、氮及其他重要矿质养分在生态系统生命组分间循环与平衡的核心生态过程。自然生态系统中,植物群落大多具有较高的物种丰富度和多样性,其混合凋落物在分解过程中也更有可能发生养分传递、化学抑制等种间互作,形成多样化的分解生境,多样性较高的分解者类群以及复杂的级联效应分解,这些因素和过程均对研究混合凋落物分解过程、揭示其内在机制形成了极大的挑战。从构成混合凋落物物种丰富度和多样性对分解生境、分解者多样性及其营养级联效应的影响等方面,综合阐述混合凋落物对陆地生态系统凋落物分解的影响,探讨生物多样性在凋落物分解中的作用。通过综述近些年的研究发现,有超过60%的混合凋落物对其分解速率的影响存在正向或负向的效应。养分含量有差异的凋落物混合分解过程中,分解者优先利用高质量凋落物,使低质量的凋落物反而具有了较高的养分有效性,引起低质量凋落物分解加快并最终使混合凋落物整体分解速率加快;而凋落物物种丰富度对土壤动物群落总多度有轻微的影响或几乎没有影响,但是对线虫和大型土壤动物的群落组成和多样性有显著影响,并随着分解阶段呈现一定动态变化;混合凋落物改变土壤微生物生存的理化环境,为微生物提供更多丰富的分解底物和养分,优化微生物种群数量和群落结构及其分泌酶的活性,并进一步促进了混合凋落物的分解。这些基于植物-土壤-分解者系统的动态分解过程的研究,表明混合凋落物分解作用不只是经由凋落物自身质量的改变,更会通过逐级影响分解者多样性水平而进一步改变分解速率和养分释放动态,说明生物多样性确实在一定程度上调控凋落物分解及其养分释放过程。     

Glial cells in peripheral nerves of the cockroach, Periplaneta americana

The ultrastructural organization and the junctional complexes of peripheral nerves have been investigated in the cockroach Periplaneta americana. Nerve 5 is surrounded by a layer of connective tissue, the neural lamella, beneath which is a layer of perineurial glial cells wrapping the axons. Adjacent perineurial cells are joined to one another by septate, gap and tight junctions. Septate and gap junctions were observed in freeze-fracture replicas of main trunk nerve 5. Septate junctions were found as rows of PF particles mainly in perineurial cell membranes. Gap junctions exhibited EF macular aggregates in perineurial and subperineurial glial cells. During incubations in vivo with extracellularly applied ionic lanthanum, the lanthanum did not penetrate beyond the perineurium. Where nerve 5 branches and contacts the muscle, lanthanum penetrated freely between the muscle fibres and the nerve branches. In small peripheral branches where the axons are surrounded by single a glial layer, lanthanum is unable to penetrate to the axolemma.     

Polarity reversal of inside-out thyroid follicles cultured within collagen gel: structure of the junctions assessed by freeze-fracture and lanthanum permeability

The organization of tight junctional complexes (TJs) was studied in cultured porcine thyroid cells during the inversion of polarity induced by collagen-embedding of inside-out follicles, using freeze-fracture replicas and lanthanum penetration. During the early steps of polarity reversal, freeze-fractures showed that TJs generally persisted. They increased in width and progressively branched out into the basolateral surfaces, towards the basal pole. Later, the number of TJ strands decreased and gap junctions inserted within TJ networks were found between cells in reversed follicles, in the same manner as in typically polarized follicles, embedded in collagen or in suspension. The de novo formation of TJ complexes was rarely found in the reversing structures. Despite the heterogeneity of TJs assessed by freeze-fracture, impermeability to lanthanum tracer was noted in inside-out structures. During the reversal process, some TJs remained unstained, whereas others displayed permeability to lanthanum. This heterogeneity might be due to the "opening" of a small number of junctions (perhaps only one by aggregate). When the process was achieved after 48 hr in collagen, the tightness of the junctions was complete, confirmed by the absence of lanthanum in luminal cavities of newly formed follicles.     

Antineoplastic activity of new lanthanide (cerium, lanthanum and neodymium) complex compounds

Cerium (III), lanthanum (III) and neodymium (III) complexes with 3,3'-benzylidenebis[4-hydroxycoumarin] were synthesized in view of their application as cytotoxic agents. The complexes were characterized by different physicochemical methods: elemental analysis, mass spectrometry, 1H NMR, 13C NMR and IR spectroscopy. The spectra of the complexes were interpreted on the basis of comparison with the spectrum of the free ligand. The vibrational analysis showed that in the complexes the ligand coordinated to the metal ion through both deprotonated hydroxyl groups; however, participation of the carbonyl groups in the coordination to the metal ion was also suggested. The evaluation of the cytotoxic activity of the novel lanthanide complexes on HL-60 myeloid cells revealed that they are potent cytotoxic agents. The cerium complex was found to exhibit superior activity in comparison to the lanthanum and neodymium coordination compounds, the latter being the least active. Our data give us reason to conclude that the newly synthesized lanthanide complexes should be submitted to further more detailed pharmacological and toxicological evaluation.     

Effects of lanthanum and calcium on photoelectron transport activity and the related protein complexes in chloroplast of cucumber leaves

The effects of lanthanum and calcium ions on electron transport, dichlorephenol indophenol (DCIP) photoreduction, and oxygen evolution activities in chloroplast from cucumber (Cucumis satives L.) were determined. The lanthanum inhibited the whole electron chain-transport activity of chloroplast. DCIP photoreduction and oxygen evolution activities of the photosystem I (PSII) also decrease after treatment with La³⁺. But the diminished activities of PSII and chloroplast caused by La³⁺ could be reversed by Ca²⁺ and even became higher than the control level. The concentration analysis of related protein complexes to photoelectron transport in chloroplast included that La³⁺ induced the concentration of chlorophyll protein complexes increasing but caused some nonchlorophyll protein complexes to decompose partially. This increasing effect of La³⁺ on chlorophyll protein complexes results in the improvement of chlorophyll content, which will improve the absorption of photoelectron and energy transport in the process of photosynthesis.     

Permeable junctional complexes. The movement of lanthanum across rabbit gallbladder and intestine

Ionic lanthanum has been used to study transepithelial ion permeation in in vitro rabbit gallbladder and intestine (ileum) by adding 1 mM La³⁺ to only the mucosal bathing solution. Transepithelial fluid transport electrical potential differences (p.d.), and resistances were measured. During La³⁺ treatment the gallbladder''s rate of active solute-coupled fluid transport remained constant, the resistance increased, and the 2:1 NaCl diffusion p.d. decreased. Mucosa-to-serosa fluxes of ¹⁴⁰La³⁺ were measured and indicate a finite permeability of the gallbladder to La³⁺. La³⁺ also increased the transepithelial resistance and p d. of ileum. Electron microscopic examination of La³⁺-treated gallbladder showed: (a) good preservation of the fine structure, (b) electron-opaque lanthanum precipitates in almost every lateral intercellular space, most frequently near the apical end of the lateral spaces close to or within the junctional complex, (c) lanthanum among the subjacent muscle and connective tissue layers, and (d) lanthanum filling almost the entire length of so-called "tight" junctions. No observations were made which unequivocally showed the penetration of lanthanum into the gallbladder cells. Electron micrographs of similar La³⁺-treated ilea showed lanthanum deposits penetrating the junctional complexes. These results coupled with other physiological studies indicate that the low resistance pathway for transepithelial ion permeation in gallbladder and ileum is through the tight junctions A division of salt-transporting epithelia into two main groups, those with "leaky" junctional complexes and those with tight junctional complexes, has been proposed.     

Ultrastructural study of tracer permeability through the cat and ferret enamel organ

The access of exogenous materials to the developing enamel surface has been intensively studied in rodents, but not in other mammalian species. This ultrastructural study investigates the permeability of injected horseradish peroxidase (HRP) and lanthanum tracers in cat and ferret tooth buds. In cat enamel organs fixed by immersion, lanthanum did not escape the capillaries overlying secretory stage tooth buds, but it did permeate up to the distal junctions of ruffle-ended (RA) and the proximal junctions of smooth-ended (SA) ameloblasts. Perfusion fixation with lanthanum compromised junctional integrity of cat ameloblasts at all stages of development. Similarly, HRP rarely escaped the capillaries associated with cat secretory stage enamel organs. However, unlike lanthanum, HRP was mostly confined to the vasculature of maturation stage enamel organs in immersion fixed cats at all time intervals examined. In ferrets, HRP penetrated up to, but not beyond, the distal junctional complexes of secretory ameloblasts. In maturation stage enamel organs, HRP coated the papillary and RA cells, but did not penetrate the RA distal cell junctions. HRP did permeate the extracellular spaces of SA to reach the underlying enamel surface. Ameloblasts in transitional phases of SA and RA endocytosed HRP at the distal cell surface. This data leads to several conclusions. First, HRP localization in the ferret paralleled that observed in rodents. Second, the results of cat enamel organs substantiate previous studies showing perfusion fixation can increase vascular and intercellular permeability to lanthanum. However, in cats fixed by immersion, both lanthanum and HRP were restricted to capillaries associated with the secretory stage enamel organ, and only lanthanum escaped maturation stage capillaries. It is suggested that variations in the fenestrations and distribution of capillaries associated with the cat enamel organ may differentially retain some materials and permit other materials to escape with relative ease.     

The effect of ascorbic acid on the breakdown of arachidonate 15-hydroperoxide in the presence of iron salts and complexes

The decomposition of 15-hydroperoxide of arachidonic acid initiated by iron and some of its complexes in the presence of ascorbate was studied using UV-absorbing measurements of conjugated dienes. The kinetics of 15-HPAA decomposition by Fe++ and Fe+(+)-EDTA was very fast and could not be registered using conventional spectrophotometry. In the presence of ascorbate addition of Fe or its complexes with EDTA and resulted in 15-HPAA decomposition, which could be measured by the changes in the UV absorption. The decomposition rate was dependent on the amount of ascorbate oxidation products formed. Preincubation of ascorbate with iron prevented the 15-HPAA decomposition by Fe++ or its complexes.     

Theoretical, spectral characterization and antineoplastic activity of new lanthanide complexes.

The new cerium(III), lanthanum(III) and neodymium(III) complexes were synthesized in view of their application as cytotoxic agents. The complexes were characterized by different physicochemical methods: elemental analysis, mass spectrometry, (1)H NMR, (13)C NMR and IR spectroscopy. The spectra of the complexes were interpreted on the basis of comparison with the spectrum of the free ligand. The vibrational analysis showed that in the complexes the ligand coordinates to the metal ion through both deprotonated hydroxyl groups, however participation of the carbonyl groups in the coordination to the metal ion was also suggested. Geometry optimization of 3,3'-(ortho-pyridinomethylene)di-[4-hydroxycoumarin] H(2)(o-pyhc), (H(2)L) and its dianionic forms, o-pyhc(2-), (L(2-)) were carried out at AM1 and PM3 levels as well as using density functional theory with Becke's three parameter hybrid method and correlation functional of Lee, Yang and Parr (B3LYP) with 6-31G(d) basis set. The optimized geometries of the neutral ligand isomers were stabilized by two asymmetrical intramolecular O-H...O hydrogen bonds (HBs). The conformational search showed four low-energy dianionic species (o-pyhc(2-)) on the potential energy surface. Molecular electrostatic potential calculations showed that the most preferred sites for electrophilic attack in H(2)(o-pyhc) and o-pyhc(2-) are the carbonyl oxygen atoms. The evaluation of the cytotoxic activity of the novel lantanide complexes on HL-60 myeloid cells revealed, that they are potent cytotoxic agents. The cerium complex was found to exhibit superior activity in comparison to the lanthanum, and neodymium species, the latter being the least active. Taken together our data give us a reason to conclude that the newly synthesized lanthanide complexes should be a subset to further more detailed pharmacological and toxicological evaluation.     

Lanthanide complexes of some macrocyclic schiff bases derived from pyridine-2,6-dicarboxaldehyde α,ω-primary diamines

The synthesis of macrocyclic lanthanide complexes via the reaction of pyridine-2,6-dicarboxaldehyde with 1,2-diaminoethane, 1,2-diaminopropane and 1,3-diaminopropane in the presence of lanthanide nitrates as templating agents is discussed together with the use of the lanthanum derivatives in transmetallation reactions with copper(II).     

The transepithelial shunt pathway in the renal proximal tubule of newt kidney

The transepithelial shunt pathway of newt proximal tubule was examined with glass micro-electrode and electron microscopic methods. The input resistance of the peritubular (basal) membrane and tubular wall were found to be $\text{4.2 ± 0.1 · 10}{}^6$ ($\text{mean ± S.E.}\text{, n = 16}$) and $\text{11.4 ± 0.2 · 10}{}^4\text{(n = 11)}$, respectively. The input resistance of the peritubular membrane was approximately 40-times larger than that of the tubular wall. When the kidneys were perfused in a lanthanum solution, the lanthanum ions were then observed in the junctional complexes and in the intercellular spaces on both the basal and apical sides. The results indicate that the electrical shunt pathway corresponds to the apical junctional complexes and the intercellular spaces, and that the tight junctions are not truly ‘tight’ for the transepithelial movement of small ions in the proximal tubule of the newt kidney.