The Toxicological Effects in Brain of Mice Following Exposure to Cerium Chloride

Cerium (Ce) compounds are now widely applied in medicine, agriculture, animal breeding, and daily life; however, the effects of Ce on human body, especially on the central nervous system, are still unclear. In order to investigate whether Ce exposure cause neurotoxicological effects, ICR mice were exposed to CeCl(3) through intragastric administration at 0, 2, 10, and 20?mg/kg body weight doses everyday for 60?days. The behaviors of spatial recognition memory, brain histopathology, the brain elements and neurochemicals, as well as enzymes activities in mice were determined. The Y-maze test showed that CeCl(3) exposure could significantly impair the behaviors of spatial recognition memory. Specifically, in these Ln(3+)-treated mice, the contents of Ca, Mg, Na, K, Fe, and Zn in brain were significantly altered, the activities of Na(+)/K(+)-ATPase, Ca(2+)-ATPase, Ca(2+)/Mg(2+)-ATPase, acetylcholine esterase, and nitric oxide synthase were significantly inhibited; monoamines neurotransmitters such as norepinephrine, dopamine, and 5-hydroxytryptamine were significantly decreased, while the contents of acetylcholine, glutamate, and nitric oxide were significantly increased. These results indicated that CeCl(3) exposure could impair the learning ability, which is attributed to the disturbance of the homeostasis of trace elements, enzymes, and neurotransmitter systems in the mouse brain. Therefore, our study aroused the attention of Ln application and long-term exposure effects.     

mdr1 Ribozyme mediated reversal of the multi-drug resistant phenotype in human lung cell lines

Anmdr1 hammerhead was introduced into two adriamycin-selected multi-drug resistant human lung cell lines both of which over-express p-glycoprotein. Expression of the ribozyme resulted in a decrease inmdr1 mRNA expression and an increase in drug sensitivity in both cell lines. This would suggest that the use of specific ribozymes may represent an effective and specific approach in order to restore cellular sensitivity towards anti-cancer drugs.     

A proposal for the physiological significance of mdr1 and Bcrp1/Abcg2 gene expression in normal tissue regeneration and after cancer therapy

Cellular multi-drug resistance (MDR), which often develops in cancer cells of patients subjected to anti-cancer treatment, remains a significant barrier to successful cancer therapy. One of the principal causes of cellular MDR development is an increased expression of ABC-transporter genes such as mdr1 and Bcrp1/Abcg2. Despite many years of intensive research, the natural biological role of mdr1 in the context of cancer has remained elusive. Some hints about this role came, however, from an observation that P-gp, the mdr1 encoded protein, is expressed widely in stem cells and from the discovery that P-gp possesses an anti-apoptotic activity independently of exogenous drug application. Here, we discuss our own and other groups' recently published works and propose an integrated view of mdr1 and Bcrp1/Abcg2 activity during tissue regeneration in normal tissues as part of a stress-induced regeneration genetic program and in cancerous tissues in response to cancer therapy.     

野生型小鼠皮肤cyclinA1 mRNA的表达及其意义

目的从RNA水平探讨cyclinA1在野生型小鼠皮肤中的表达及意义。方法选取30只大于6个月的野生型小鼠,用原位杂交方法定位检测cyclinA1 mRNA在头颈部皮肤中的表达,同时以不加探针皮肤标本作为阴性对照,另取雄性小鼠睾丸组织作为阳性对照。结果分别有25只野生型小鼠在皮脂腺部位及12只在表皮全层有cyclinA1 mRNA表达。其中,皮脂腺部位强阳性及阳性表达分别占50.0%和33.3%,阳性率为83.3%;表皮全层强阳性及阳性表达分别占13.3%和26.7%,阳性率为40.0%。皮脂腺阳性率显著高于表皮(P0.05)。结论CyclinA1 mRNA在野生型小鼠头颈部皮肤的皮脂腺部位及表皮全层的表达均有较高的阳性率,尤其皮脂腺表达的阳性率更高。     

水稻病程相关基因OsPR1b启动子的表达特性研究

目的:分析水稻病程相关基因OsPR1b的表达特性,以进一步了解其表达和调控机制。方法:利用PCR技术从水稻日本晴基因组中扩增OsPR1b基因的启动子片段,命名为OsPR1bp,并构建相应的OsPR1bp::GUS融合表达载体,采用农杆菌介导的转基因技术获得转基因植株,进行GUS组织化学分析;利用Real-time PCR对OsPR1b基因在植物激素、非生物因子和水稻白叶枯菌(Xoo)毒性菌株P10(PXO124)处理下的表达水平进行分析。结果:GUS组织染色结果表明OsPR1b在水稻叶片中的表达量较高,而在茎、根、愈伤和花器中的表达量较低;植物激素水杨酸(SA)、茉莉酸甲酯(MeJA)、激动素(KT)、脱落酸(ABA)及NaCl、PEG均可不同程度地提高OsPR1b在叶片中的表达水平,Me-JA、KT和NaCl的处理能提高其在根部的表达水平,但这些激素在诱导OsPR1b在叶片和根部的表达程度上存在明显差异;单独接种Xoo毒性菌株P10 24 h对OsPR1b表达的影响不大,而MeJA与其共同处理后则可显著增强其在叶片中的表达。结论:作为一种防卫基因,OsPR1b在健康植株中的表达水平较低,容易受盐/干旱胁迫及Xoo病原菌的诱导,多种植物激素如JA、KT和ABA很可能作为信号分子参与激活和介导了这种系统性的反应。     

维甲酸诱导的脊柱裂小鼠的脊髓全基因组表达谱分析(英文)

关于维甲酸胚胎病理学的研究很多,维甲酸受体在器官发生、发育及神经管闭合过程中发挥重要作用。但维甲酸影响这些过程的机制还不清楚。在本研究中,我们发现,小鼠怀孕8天时,给予母体连续3次维甲酸灌胃,将导致胎儿脊柱裂,发生率为96.77%。本研究应用微阵列技术,在维甲酸诱导的脊柱裂小鼠胎儿的脊髓组织中发现了134个差异表达在1.5倍以上的基因。基因富集分析显示,母亲暴露于维甲酸导致的胎儿脊柱裂,与促凋亡和抗凋亡、细胞增殖、迁徙、细胞骨架成分以及细胞或局部粘附等基因功能簇相关,提示这些细胞成分和生物学的功能缺陷促使脊柱发育异常。我们的研究提供了脊柱裂的全基因组基因表达模式,有助于理解神经管缺陷的病因和病理学。     

氯化钴对H9c2心肌细胞新基因Mipu1表达的影响

目的：研究氯化钴（CoCl2）对大鼠胚胎心脏来源的H9c2心肌细胞中新基因Mipu1表达的影响。方法：利用不同浓度的CoCl2（0、100、200、300、400、500μmol/L）处理H9c2细胞9h,及200μmol/L CoCl2处理H9c2细胞不同的时间（0、6、9、12、24h）后,用RT-PCR和Western Blot分别观察H9c2细胞Mipu1 mRNA和蛋白的表达情况。结果：CoCl2可以诱导H9c2细胞中Mipu1 mRNA和蛋白表达升高,200μM CoCl2处理组的Mipu1的表达水平高于100μM CoCl2处理组,但是更高浓度的CoCl2（〉200μM）不能使Mipu1的表达进一步升高。随着CoCl2作用时间的延长,Mipu1的表达逐步升高,在12h达到高峰,但是在24h后下降。结论：CoCl2能够促进H9c2细胞新基因Mipu1的表达,并且具有一定的剂量和时间依赖性。     

Increased CD11b+ Gr‐1+ cell population in the placenta after infection with Toxoplasma gondii

Toxoplasma gondii is an obligate intracellular protozoan pathogen that can cross the placenta, resulting in congenital toxoplasmosis with severe fetal brain abnormalities. The molecular mechanisms of immune responses against T. gondii infection in the placenta have largely remained unclear. An analytical method for characterizing phenotypes of immune cells in the placenta by flow cytometry was established and it was found that numbers of CD11b⁺ Gr‐1⁺ cells in the placenta increased significantly after T. gondii infection. These results suggest that innate immune responses play an important role in immunity against T. gondii infection via the feto‐maternal interface.     

氯化钴对H9c2 心肌细胞新基因Mipu1 表达的影响

目的:研究氯化钴(CoCl2)对大鼠胚胎心脏来源的H9c2心肌细胞中新基因Mipu1表达的影响。方法:利用不同浓度的CoCl2(0、100、200、300、400、500μmol/L)处理H9c2细胞9h,及200μmol/L CoCl2处理H9c2细胞不同的时间(0、6、9、12、24h)后,用RT-PCR和Western Blot分别观察H9c2细胞Mipu1 mRNA和蛋白的表达情况。结果:CoCl2可以诱导H9c2细胞中Mipu1 mRNA和蛋白表达升高,200μM CoCl2处理组的Mipu1的表达水平高于100μM CoCl2处理组,但是更高浓度的CoCl2(>200μM)不能使Mipu1的表达进一步升高。随着CoCl2作用时间的延长,Mipu1的表达逐步升高,在12h达到高峰,但是在24h后下降。结论:CoCl2能够促进H9c2细胞新基因Mipu1的表达,并且具有一定的剂量和时间依赖性。     

病原诱导的小麦ERF转录因子TaERF1b的原核表达及纯化

为了得到纯化的TaERFlb活性蛋白,将TaERFlb基因含有AP2／ERF结构域的片段插入原核表达载体pGEX-4T-1的多克隆位点中,构建GST-TaERFlb融合蛋白表达载体,并转化到犬肠杆菌BL21（DE3）中。0．1mmol／L1PTG即能诱导融合蛋白表达,37℃诱导4h或30℃诱导8h,融合蛋白均以包涵体的形式表达,16℃诱导12h,融合蛋白不表达。包涵体经溶解及稀释复性后,过GST亲和层析柱,获得纯化的融合蛋白,考马斯亮蓝法测得纯化蛋白的浓度约为0．5ug／ul,凝胶阻滞实验表明包涵体复性成功．所得蛋白具有生物活性：     

Uptake of 125I-labelled α2-macroglobulin and albumin by human placental syncytiotrophoblast in vitro

We have investigated the binding and internalization of α₂-macroglobulin and serum albumin by human placental syncytiotrophoblast cells in vitro. The time course (obtained at 4°C) of α₂-macroglobulin binding indicated that an equilibrium was reached after 4 h. The binding of ¹²⁵I-labelled α₂-macroglobulin to syncytiotrophoblast cells was competitively reduced in the presence of excess unlabelled α₂-macroglobulin. When the concentration-dependence of binding was examined over a wide concentration range, non-linear regression analysis yielded a K_d of 6.4 nM. In the case of albumin, binding was weak and ligand dissociated from the cell surface during aqueous washing making it impractical to analyze the binding reaction. In other experiments, syncytiotrophoblast cells were incubated with ¹²⁵I-labelled α₂-macroglobulin at 37°C. Under these conditions, trypsin-resistant cell-associated radioactivity increased with time consistent with ligand internalization. ¹²⁵I-Labelled-ligand was internalized with a t_1/2 of about 5 min. After a lag period some radioactivity was released back into the incubation medium. When measured at times up to 210 min, this was found to consist of mostly TCA-precipitable material that had been lost from the cell surface. However, when the incubation was extended to 24 h, almost 15% of the initial cell-associated radioactivity was released to the extracellular medium as TCA-soluble material, consistent with a slow rate of ligand degradation. The specific binding of ⁶⁵Zn-labelled α₂M was similar to that of the ¹²⁵I-labelled ligand and trypsin-resistance measurements provided evidence of α₂M-mediated ⁶⁵Zn uptake. These results support a role for syncytiotrophoblast in the metabolism of α₂-macroglobulin during pregnancy and are also consistent with a role for α₂-macroglobulin in the maternal-fetal transport of zinc. J. Cell. Biochem. 68:427–435, 1998. © 1998 Wiley-Liss, Inc.     

Effects of Maternal Exposure to Imazalil on Behavioral Development in F1‐Generation Mice

Female mice were exposed maternally to imazalil through diet to provide levels of 0 (control), 0.0006, 0.0018, and 0.0054% during gestation and lactation periods, and selected reproductive and neurobehavioral parameters were measured in F₁ generation. There was no adverse effect of imazalil on litter size, litter weight, or sex ratio at birth. With respect to behavioral developmental parameters, surface righting on postnatal day 4 of male offspring was delayed significantly in a dose‐related manner (p < 0.05). Regarding exploratory behavior in the F₁ generation, movement time was significantly long (p = 0.0206) in the low‐dose group of males at 8 weeks of age. Spontaneous behavior examination in males indicated that movement time increased but in females decreased in the low‐dose groups in the F₁ generation. The dose levels of imazalil in the present study produced some adverse effects in neurobehavioral parameters in mice.     

Multidrug resistance gene deficient (mdr1a–/–) mice have an altered caecal microbiota that precedes the onset of intestinal inflammation

Aim:  To compare caecal microbiota from mdr1a ^–/– and wild type (FVB) mice to identify differences in the bacterial community that could influence the intestinal inflammation.
Methods and Results:  Caecal microbiota of mdr1a ^–/– and FVB mice were evaluated at 12 and 25 weeks of age using denaturing gradient gel electrophoresis (DGGE) and quantitative real-time PCR. DGGE fingerprints of FVB and mdr1a ^–/– mice (with no intestinal inflammation) at 12 weeks revealed differences in the presence of DNA fragments identified as Bacteroides fragilis , B. thetaiotaomicron , B. vulgatus and an uncultured alphaproteobacterium. Escherichia coli and Acinetobacter sp. were only identified in DGGE profiles of mdr1a ^–/– mice at 25 weeks (with severe intestinal inflammation), which also had a lower number of total bacteria in the caecum compared with FVB mice at same age.
Conclusions:  Differences found in the caecal microbiota of FVB and mdr1a ^–/– mice (12 weeks) suggest that the lack of Abcb1 transporters in intestinal cells due to the disruption of the mdr1a gene might lead to changes in the caecal microbiota. The altered microbiota along with the genetic defect could contribute to the development of intestinal inflammation in mdr1a ^–/– mice.
Significance and Impact of the Study:  Differences in caecal microbiota of mdr1a ^–/– and FVB mice (12 weeks) suggest genotype specific colonization. The results provide evidence that Abcb1 transporters may regulate host interactions with commensal bacteria. Future work is needed to identify the mechanisms involved in this possible cross-talk between the host intestinal cells and microbiota.