稀土La3+跨PC12细胞膜行为研究

使用AR-CM-M1C阳离子测定系统,发展Fura-2荧光测定技术,将其应用于测定细胞内游离稀土离子La³⁺,并以此研究了La³⁺跨PC12细胞（大鼠嗜铬细胞瘤细胞）膜的行为.结果表明：在模拟细胞内离子组分,pH=7.05的溶液中,测得La³⁺-Fura-2的表观解离常数为3.27×10^-11 mol·L^-1.对于PC12细胞,静息条件下La³⁺不能跨越细胞膜进入胞内.与钙离子通道相关的KCl和去甲肾上腺素均不能刺激稀土La³⁺过膜.用哇巴因（ouabain）使胞内Na⁺超载后,La³⁺可过膜进入细胞内,且过膜量与胞外La³⁺浓度和胞内Na⁺超载程度有一定的浓度依赖关系,提示La³⁺可以经由Na⁺／La³⁺交换机制过膜而进入细胞内.     

增强UV-B辐射对小麦根尖细胞游离钙离子分布的影响

以小麦根尖为材料,利用低温装载法在根尖细胞中成功地装载了酯化形式的钙离子荧光指示剂fluo-3/AM,利用激光共聚焦显微技术检测了增强UV-B辐射后小麦根尖细胞内游离钙离子荧光强度的分布,并对胞质内游离钙离子浓度进行了测定.结果表明:(1)对照组小麦根尖细胞内钙离子荧光主要分布于细胞胞质周缘;而经UV-B辐射处理后,细胞内钙离子荧光不仅分布在胞质周缘,且在细胞壁与胞间隙可观察到大量钙离子荧光.(2)对单个细胞内钙离子荧光强度进行测定,发现UV-B处理使细胞胞质内游离钙离子浓度明显升高.     

脉冲电场对粒细胞内Ca2+浓度影响的动态变化

利用激光共聚焦扫描显微镜和装有CCD系统的荧光显微镜,研究在单脉冲电场作用下经fluo-3/AM标记的鸡胚小脑粒细胞内自由Ca2+浓度(i)的动态变化过程.结果表明:在单个电脉冲作用下,细胞内Ca2+浓度立刻升高并达到其最大值.Ca2+浓度升高的幅度以及升高的速率具有电场强度的依赖性.当细胞外Ca2+被过量的EGTA络合或细胞膜上的Ca2+通道被La3+堵塞后,细胞内的Ca2+浓度仍然升高.细胞内不同区域的Ca2+浓度同时升高;两极内的Ca2+浓度早于胞体的Ca2+浓度达到最大值并迅速恢复.     

单细胞内Ca2+时空变化的激光共聚焦显微测定

应用激光扫描共聚焦显微系统(LSCM)和Fluo-3/AM荧光探剂标记技术, 测定了单个活细胞胞内游离Ca²⁺的动态变化与立体分布影像. 结果显示, 在37℃, Fluo-3/AM终浓度为6μmol/L的条件下, C57BL/6J小鼠巨噬细胞负载1h左右即可获得良好的标记效果. 相反, 若探剂浓度太高或负载时间太长, 胞内荧光强度太强, 影响在共聚焦显微镜镜下分辨细胞内结构. 因此用LSCM研究细胞内游离Ca²⁺变化时, 荧光探剂的负载应以获得最适荧光信号而不是以最大荧光强度为标准. 上述方法在其他如平滑肌细胞、卵母细胞中的测定亦获得满意的结果, 这对进一步研究各种生理和病理条件下细胞内Ca²⁺信号的动态变化、与跨膜Ca²⁺梯差的关系及对活细胞功能活动的调节提供了一种可行的、直观的研究手段.     

四种生态型芦苇叶中离子分布对生境的生理适应

采用X射线微区分析技术,测定了4种生态型芦苇(Phragmites australis (CaV.) Trin. exSteud.)叶的表皮泡状细胞、叶肉细胞和叶脉维管束鞘细胞离子的含量.结果表明:沼泽芦苇的鞘细胞内,K+、Na+、Ca2+、Mg2+和Cl-分布均较叶肉细胞和泡状细胞高.沙丘芦苇的泡状细胞中Ca2+分布较叶肉细胞和鞘细胞高,而Mg2+在其叶肉细胞,以及K+、Na+和Cl-在其鞘细胞内分布均较高.在轻度盐化草甸芦苇的叶肉细胞内分布较多的Na+和Mg2+,而在鞘细胞内K+、Ca2+ 和Cl-的分布均较叶肉细胞和泡状细胞为高.重度盐化草甸芦苇的泡状细胞内Na+和Mg2+的分布较多;同样,在叶肉细胞中K+、Ca2+和Cl-的分布也较多.最后,讨论了上述各种离子在不同生态型芦苇叶内分布的状况, 以及与其环境适应的生理意义.     

细胞外钠离子浓度对羊浦肯野纤维膜钠泵活动的影响

采用离子选择电极测量羊浦肯野纤维细胞膜内钠离子活度(~(ai)N_a),细胞间钾离子活度(a~ok)及细胞膜电位(v_m),观察不同浓度低钠,无钙液对其影响,在无钙低钠液中,细胞内Na~+逐出,α~iNa 降低,其变化速率,幅值与[Na]_o 相关,同时也受细胞 a~iNa 初始水平(aiNa(o))的影响。aiNa 下降6min 时的稳态水平与[Na]_o 呈直线正相关,这些结果表明,[Na]_o 降低时,细胞膜钠泵活动加强,细胞内 Na~+逐出增加,其最终结果是使 Na+跨膜梯度维持相对稳定,因而可以认为是 Na~+跨膜梯度而不是单纯的细胞内 Na~+控制膜钠泵活动。在低 Na~+液引起细胞内 Na~+主动逐出增加的同时,细胞膜出现超极化,[Na]_o 愈低,膜超极化程度愈高,从低钠液引起的 a~i_(Na),V_m,α~o_k 变化之间的时程关系看,膜超极化主要由加大的外向泵电流引起,同时发生的细胞间 K~+浓度变化对其也有一定影响。     

NaCl胁迫下大麦根液泡膜H+-ATPase活性、离子吸收与钙的关系

NaCl胁迫2 d,耐盐大麦(Hordeum vulgare L.cv) ("滩引2号")根系液泡膜H+-ATPase活性增强,H+-PPase活性下降.以质膜Ca2+通道抑制剂La3+ (1 mmol/L)或Ca2+螯合剂EGTA (5 mmol/L)处理大麦幼苗,抑制了NaCl诱导的液泡膜H+-ATPase活性的增强,但提高了H+-PPase活性;用CaM拮抗剂三氟拉嗪(TFP,20 μmol/L)处理,也抑制了液泡膜H+-ATPase活性的增强.NaCl胁迫下,外加La3+,TFP或La3++TFP处理,使Na+吸收增加,K+和Ca2+吸收降低.结果表明,NaCl胁迫下,液泡膜H+-ATPase活性提高和离子吸收的变化可能与Ca-CaM系统有关.     

用EDTA法研究镰刀菌胞内、胞外Pb2+的分布特征

【目的】建立一种方便、快捷、相对准确、能够定量地测定镰刀菌细胞内、外Pb2+分布的技术手段。【方法】用EDTA溶液浸泡镰刀菌细胞,使其胞外(表面)Pb2+被螯合、洗脱并测定,之后将被浸泡、清洗过的细胞消解、测铅。【结果】EDTA可以将镰刀菌表面的Pb2+螯合,且在99 min内不损伤镰刀菌细胞;以EDTA为反应介质和滴定剂,XO为指示剂,测定镰刀菌胞内、胞外Pb2+分布是可行的。依据此实验方法,测定了镰刀菌在Pb2+浓度为500 mg/L的培养基中的生长曲线、培养基中Pb2+浓度和细胞内、外Pb2+的含量。【结论】镰刀菌固定Pb2+的过程是先将Pb2+吸附在菌体胞外,之后转运至细胞内部,菌体胞外Pb2+的容纳量是有限的,每克菌体胞外Pb2+饱和吸附量约1.37 mg,通过计算可得,每克菌体用于吸附Pb2+的胞外活性位点约3.97×1018个。     

脉冲电场对粒细胞内Ca2+浓度影响的动态变化

利用激光共聚焦扫描显微镜和装有CCD系统的荧光显微镜 ,研究在单脉冲电场作用下经fluo 3/AM标记的鸡胚小脑粒细胞内自由Ca²⁺浓度 ( [Ca ²⁺]_i)的动态变化过程 .结果表明 :在单个电脉冲作用下 ,细胞内Ca²⁺浓度立刻升高并达到其最大值 .Ca²⁺浓度升高的幅度以及升高的速率具有电场强度的依赖性 .当细胞外Ca²⁺被过量的EGTA络合或细胞膜上的Ca²⁺通道被La ³⁺堵塞后 ,细胞内的Ca²⁺浓度仍然升高 .细胞内不同区域的Ca²⁺浓度同时升高 ;两极内的Ca²⁺浓度早于胞体的Ca²⁺浓度达到最大值并迅速恢复 .     

人源性长寿保障基因2通过与V-ATPase作用抑制肝癌细胞的生长

人源性长寿保障基因2(Homo sapiens longevity assurance homologue2,LASS2)是本实验室克隆到的一个与酵母长寿保障基因LAG1高度同源的人类新基因。前期研究显示,LASS2可与V-ATPase质子泵的c亚基ATP6L结合,过表达LASS2可以抑制肝癌细胞SMMC-7721的生长。本研究旨在探讨LASS2对V-ATPase质子泵功能的调节是否参与LASS2对肝癌细胞生长的抑制作用。使用本室构建、保存的pCMV-HA2-LASS2质粒瞬时转染肝癌细胞(HCCLM3),而未转染质粒的HCCLM3细胞作为空白对照,运用CCK-8试剂盒检测细胞生长情况;采用BCECF-AM和BCECF氢离子敏感探针分别测定细胞内、外H+浓度;应用流式细胞仪检测细胞凋亡;Western blot检测线粒体和胞质内细胞色素c(cytochrome c,Cytc)、胞质中的无活性pro-caspase-3的表达情况。结果显示,外源性LASS2的过表达对HCCLM3细胞生长有抑制作用;过表达LASS2使HCCLM3细胞内H+浓度上升,细胞凋亡率提高,线粒体Cyt c释放增加,胞质中pro-caspase-3含量下降。以上结果提示提示LASS2可能通过调控V-ATPase质子泵的功能,提高细胞内H+浓度,从而激活细胞线粒体凋亡途径、抑制肝癌细胞的生长。     

La(NO3)3浸种对镉胁迫下油菜种子萌发及幼苗生长的影响

通过水培实验研究了La(NO3)3浸种对镉胁迫下油菜(Brassicanapus)种子萌发及幼苗生长的影响。结果表明,当镉浓度≤10mg·L-1时,La(NO3)3浸种(0～50mg·L-1)能提高油菜种子的活力,促进油菜幼苗的生长,并提高脂肪酶的活性和幼苗根细胞有丝分裂指数。其中以10mg·L-1La(NO3)3浸种处理效果最佳,与对照相比,种子活力指数及油菜幼苗各生长指标显著提高,脂肪酶活性增加40.41%～65.09%,幼苗根细胞有丝分裂指数增加62.76%～77.02%。当镉浓度>10mg·L-1时,La(NO3)3浸种对镉胁迫的缓解效用明显减弱,与对照相比,仅脂肪酶活性显著提高,其它指标无明显变化。     

硝酸镧对香蕉幼苗两个抗寒生理指标的影响

在人工气候箱中进行人工模拟寒潮对香蕉的冷害 ,研究硝酸镧对改善香蕉抗寒性的生理作用。结果表明 :香蕉幼苗叶面喷施 0 .2 5～ 0 .2 8mmol/L浓度硝酸镧后 ,可提高香蕉叶片过氧化物酶的活性 44.2 %～61 .5 %及降低相对电导率 1 7.6%～ 2 7.7%。     

镧对烟草愈伤组织和油菜幼根钙含量的影响

ＭＳ培养基中添加镧（Ｌａ）（０ ．０１ ～０ ．１０ｍ ｍｏｌ·Ｌ－ １） 培养烟草愈伤组织,其总Ｃａ２ ＋ 及原生质体Ｃａ２ ＋ 含量明显比对照（ 不加Ｌａ） 低;长时间（ 继代培养３０ｄ） 较短时间培养（ 悬浮培养２４ｈ） 低．低浓度（０ ．０１ ～０ ．０５１ｍｏｌ·Ｌ－ １）Ｌａ３ ＋ 使细胞壁中Ｃａ２ ＋ 含量高于对照并随浓度提高而增加,高浓度（０ ．１０１ｍｏｌ·Ｌ－ １） 则减少．与Ｃｅ２ ＋ 相比较,Ｌａ３ ＋ 的排Ｃａ２ ＋ 作用稍弱于Ｃｅ３ ＋ ．以不同浓度Ｌａ（ＮＯ３）３ 溶液浸种,油菜幼根总Ｃａ２ ＋ 及原生质体中Ｃａ２ ＋ 含量变化与上述类似．Ｌａ３ ＋ 使烟草愈伤组织褐化明显,生长量比对照低．     

Synthesis,characterization, and electrocatalytic behaviour of hydrothermally grown nanostructured La2O3 and La2O3/K-complex

Rare earth metals play a conspicuous role in magnetic resonance imaging (MRI) for detecting cancerous cells. The alkali metal potassium is a neurotransmitter in the sodium–potassium pump in biomedical sciences. This unique property of rare earth metals and potassium drew our attention to carry forward this study. Therefore, in this work, previously synthesized potassium (K) complexes formed by the reflux of 4-N,N-dimethylaminobenzoic acid (DBA) and potassium hydroxide in methanol, and named [(μ2–4-N,N-dimethylaminobenzoate-κO)(μ2–4-N,N-dimethylaminobenzoic acid-κO)(4-N,N-dimethylaminobenzoic acid-κO) potassium(I) coordination polymer)] were treated hydrothermally with La₂O₃ nanomaterials to obtain a nanohybrid La₂O₃/K-complex. After that, the K-complex was analyzed using single-crystal X-ray diffraction and ¹H and ¹³C NMR spectroscopy. In addition, the structural and morphological properties of the as-prepared nanostructured La₂O₃/K-complex were also characterized, which involved an investigation using X-ray diffraction (XRD)spectroscopy, Fourier transform infrared (FTIR) spectroscopy, atomic force spectroscopy (AFM), transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) analysis. After this, the electrochemical redox behaviour of the synthesized nanohybrid material was studied using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Therefore, the results from these studies revealed that the as-prepared material was a La₂O₃/K-complex that has a promising future role in sensing various analytes, as it showed effective electrocatalytic behaviour.     

La3+-promoted proliferation is interconnected with apoptosis in NIH 3T3 cells

Lanthanum ion (La(3+)) has been reported to affect proliferation or apoptosis of different cells. In the present study, La(3+) was confirmed to promote both proliferation and apoptosis of NIH 3T3 cells at the same concentrations. La(3+) was shown to promote proliferation by helping the cells to pass through the G1/S restriction point and enter S phase, however, the proliferating cells induced by incubation with La(3+) eventually underwent apoptosis. The proliferation and apoptosis of NIH 3T3 cells induced by La(3+) were well correlated with cell cycle alterations. La(3+) caused the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2; while inhibition of ERK phosphorylation by 2'-amino-3'-methoxyflavone (PD98059) suppressed both proliferation and apoptosis induced by La(3+). Based on the above experimental results, we postulated that La(3+)-promoted proliferation of NIH 3T3 cells could be interconnected with the cell apoptosis, possibly through cell cycle machinery. Our results thus support the recent hypothesis that proliferation and apoptosis of cell are intrinsically coordinated.     

镧浸种对水稻种子萌发及幼苗生长的影响

以水稻种子为材料,研究了稀土元素镧对水稻种子活力和幼苗生长的影响。结果表明,1~20mg.L-1La3+处理能提高水稻种子的活力,提高蛋白酶、淀粉酶和脂肪酶的活性,并能促进水稻茎、叶和根系的生长,其中10mg.L-1La3+处理效果最佳。当浓度超过30mg.L-1时,水稻种子萌发和幼苗生长受到抑制。此外,镧对水稻植株地下部分(根系)生长的影响比地上部分(茎叶)生长的影响要明显。镧对水稻种子萌发期间3种酶活性的影响程度表现为蛋白酶>脂肪酶>淀粉酶。     

硝酸镧提高黑麦草种子活力和幼苗生物量的生理效应

研究了不同浓度硝酸镧对黑麦草种子萌发和幼苗生长的影响及其生理生化变化。结果表明,低浓度硝酸镧（1000mg·L^-1）处理能够提高黑麦草种子的活力和萌发种子的淀粉酶、蛋白酶和脂肪酶活性及IAA、GA和CTK含量;促进幼苗光合速率提高和干物质积累,这可能与硝酸镧提高幼苗叶片叶绿素含量和叶绿体希尔反应活力,促进光合电子传递和磷酸化反应及激活Rubisco羧化活性、PEP羧化酶活性有密切关系,其中以30mg．L^-1浓度处理的效果最佳;高浓度硝酸镧（70-100mg·L-1）处理则降低种子活力和抑制幼苗生长。而10-100mg．L-1硝酸镧对种子的萌发率、ABA含量和Rubisco的加氧活性影响不大。由此可见,低浓度硝酸镧可通过参与萌发和光合过程的调控提高黑麦草种子的活力,促进幼苗生长。     

Lanthanum enhances in vitro osteoblast differentiation via pertussis toxin-sensitive gi protein and ERK signaling pathway

Converging lines of evidence suggest that lanthanum tends to deposit in bone. The influence of lanthanum ion (La3+) on osteoblast differentiation and the related mechanism are essential to understanding its effect on bone metabolism. In this study, La3+ treatment enhanced in vitro osteoblast differentiation as evidenced by promoting alkaline phosphatase (ALP) activity, osteocalcin (OC) secretion, and matrix mineralization. The expressions of osteoblast-specific genes of Cbfa-1, osteopontin (OPN), and bone sialoprotein (BSP) were all increased in the presence of La3+, but no change was observed in that of type I collagen (COL-I). Further studies demonstrated that La3+ treatment enhanced phosphorylation of extracellular signal-regulated kinase (ERK). Inhibition of ERK activation by U0126 suppressed the effects of La3+ on osteoblast activity. Moreover, pretreatment of the cells with pertussis toxin (PTx), a Gi protein inhibitor, suppressed the La3+-enhanced ERK phosphorylation and osteoblast differentiation. These findings suggest that La3+ exposure enhances in vitro osteoblast differentiation and the effect depends on ERK phosphorylation via PTx-sensitive Gi protein signaling.     

稀土元素对油菜菌核病菌生长及其生化性状影响的研究

研究了氧化镧 (La2 O3 )对油菜菌核病菌 (Sclerotiniasclerotiorum ,Ss)生长及其生化性状的影响 .结果表明 ,La2 O3 浓度在 3 0～ 45 0mg·L-1时 ,固体培养和液体培养中对Ss生长均呈明显抑制作用 ,且生长抑制率 (Y)随La2 O3 浓度增加而相应增加 .液体培养中油菜菌核病菌产生的果胶酶活性随溶液中La2 O3 浓度增加而相应增加     

Sensitive and selective system of benzene detection based on a cataluminescence sensor

Au/La₂O₃ nanomaterials were prepared through calcining Au‐modified La(OH)₃ precursors. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X‐ray diffractometry (XRD) were employed to characterize the as‐prepared samples. Benzene, a common volatile organic compound, was selected as a model to investigate the cataluminescence (CTL)‐sensing properties of the Au/La₂O₃ nanomaterials. Results indicated that the as‐prepared Au/La₂O₃ exhibited outstanding CTL properties such as stable intensity, high signal‐to‐noise values, and short response and recovery times. Under optimized conditions, the benzene assay exhibited a broad linear range of 1–4000 ppm, with a limit of detection of 0.7 ppm, which was below the standard permitted concentrations. Furthermore, the gas sensor system showed outstanding selectivity for benzene compared with seven other types of common volatile organic compounds (VOCs). The proposed gas sensor showed good characteristics with high selectivity, fast response time and long lifetime, which suggested the promising application of the Au/La₂O₃ nanomaterials as a novel highly efficient CTL‐sensing material. Copyright © 2013 John Wiley & Sons, Ltd.