基于单分子量子相干调制的细胞温度成像技术

目的细胞温度成像可以帮助科学家研究和理解细胞内部的温度分布,揭示细胞代谢和生物化学过程的关键信息。目前,基于荧光温度探针的细胞温度成像技术存在低温度分辨率和有限测量范围等限制。本文旨在利用单分子量子相干过程依赖温度的特性,开发一种单细胞温度成像和实时检测技术。方法基于飞秒脉冲激光制备延时和相位可调的飞秒脉冲对,调制的脉冲对通过显微系统激发细胞内标记的荧光单分子,之后收集并记录每个荧光光子的到达时间。利用单分子相干过程与周围环境温度的关系,定义单分子量子相干可视度(V),建立V与环境温度的对应关系。通过调制解调荧光光子的到达时间,获取单分子周围环境温度,结合扫描成像,实现细胞的温度成像和实时检测。结果该方法可以实现高精度(温度分辨率<0.1℃)和大范围温度(10~50℃)的温度成像和测量,并观测到了单个细胞代谢相关的温度变化。结论该研究有助于深入了解细胞代谢、蛋白质功能和疾病机制,为生物医学研究提供重要工具。

氮掺杂碳量子点的制备及在细胞温度传感中的应用

该研究以生物质西红柿为碳源和氮源,通过微波法制备了氮自掺杂碳量子点(N-CQDs)。通过场发射透射电子显微镜(TEM)、X射线光电子能谱仪(XPS)和荧光光度计等对其形貌、结构、稳定性、光电性能、温敏性及细胞毒性进行考察,并用于活细胞温度传感研究。实验结果表明,所制备的N-CQDs稳定性强,光电性能优异,对温度具有较强的敏感性。在25~65℃范围内,N-CQDs的荧光强度随着温度的升高而降低,两者呈良好的线性关系。N-CQDs能穿透4T1细胞的细胞膜,显示出低毒性和生物相容性,在4T1细胞中具有良好的温度传感性能。该N-CQDs在活细胞荧光温度传感领域具有较大的应用潜能,有望作为温敏型纳米荧光探针在细胞研究等生物医学领域得到广泛应用。

一种高精度微芯片用于微环境中细胞温度波动监测

温度是生物体中重要的参数,准确测量细胞在代谢过程中的温度波动可为更深入地探究细胞的能量产生和扩散过程提供有价值的信息,从而促进癌症和其他疾病的研究.本文基于微机电加工和微流控技术制备一批可在微环境下监测细胞代谢过程中温度波动的微芯片.微芯片由捕获细胞的C形"微坝"结构、供液体流动的"微缝"和监测温度波动的电极结构组成.可将细胞培养、温度监测在微芯片上完成.将有细胞贴壁生长的微芯片放置在37℃恒温环境中,采用恒电流法实时在线连续监测细胞在代谢过程中的温度波动.该芯片共有9个检测单元,每个单元的检测都是完全独立的,可同时检测多个结构上的细胞温度波动情况.微芯片的准确度优于0.013℃,精度为±0.014℃,响应速度约0.1 s,不同厚度Ti/Pt温度传感器的温度-电阻之间的线性拟合参数R2大于0.999.在(37±0.015)℃的恒温环境下监测细胞,发现人肺腺癌细胞系(human lung adenocarcinoma cell,H1975)在代谢过程中温度波动的极差(0.173℃)大于肝星状细胞(hepatic stellate cell,HSC)的极差(0.127℃).癌细胞H1975的平均温度(37.001℃)高于正常细胞HSC的平均温度(36.989℃).该芯片为细胞代谢监测、药物筛选等方面提供了新的研究平台.

mAb-EGFR功能化修饰的纳米金棒靶向光热作用对下咽癌FADU细胞株和293T细胞株的温度影响

目的：探讨上皮生长因子受体单克隆抗体（epidermal grow th factor receptor monoclonal antibody ， mAb－EGFR）功能化修饰的纳米金棒靶向光热作用对下咽癌FADU细胞株和非肿瘤细胞的温度影响。方法在CTAB体系下合成实验所需纳米金棒并完成上皮生长因子受体（epidermal growth factor receptor ，EGFR）单克隆抗体功能化修饰，用紫外分光光度计及电镜表征；以体外培养的下咽癌FADU 细胞和非肿瘤细胞293T 细胞系为实验材料，用western blot免疫印迹法定性比较两株细胞EGFR的表达及明确细胞内吞纳米金棒；Annexin－5／PI双染法荧光显微镜观察FADU细胞和293T 细胞凋亡情况；设定不同剂量纳米金浓度（15％、25％、35％），应用808 nm波长近红外激光照射6分钟，每隔一分钟检测细胞培养介质温度，并用X T T 法检测细胞存活率。结果纳米金棒浓度在15％～25％、近红外激光照射6分钟时，细胞温度为41～43℃，并且趋于稳定，对下咽癌细胞有明显的杀伤作用（P＜0．05），而对293T 细胞没有明显的杀伤作用，而纳米金棒浓度在35％时对下咽癌 FADU细胞和293T细胞都具有明显的杀伤作用（P＜0．05）。结论浓度为15％～25％ mAb－EGFR功能化修饰的纳米金棒在近红外激光照射6分钟时细胞温度升至41～43 ℃，对下咽癌细胞具有明显的杀伤作用，而对非肿瘤细胞无明显损伤。

基于微纳材料与器件测量细胞温度

最近10年里,科研人员研发了多种微纳尺度测温传感器,希望能够借此来精确测量细胞内的温度或温度分布,但由于单个细胞的诸多限制,这些细胞测温传感器也在不断发展完善.本文将综述近年来基于微纳材料与器件测量细胞温度的研究进展,重点介绍微纳热电偶的实时细胞测温技术,最后介绍此类传感器在药物筛选、疾病诊疗等领域中的应用,并对细胞测温技术的后续发展进行了展望.具体而言,本文指出微纳尺度的细胞测温传感器一般可以分为荧光式细胞温度测量法和探极式细胞温度测量法:荧光式细胞温度测量法主要有作为温度计的有机化合物、量子点、聚合物和生物分子;探极式细胞温度测量法主要有作为热探针的热电偶、铂电阻和碳纳米管.

聚合物荧光温度计的制备及其细胞内温度成像研究

细胞内温度变化的研究与代谢通路息息相关,因此构建细胞内的温度响应探针研究能量代谢与温度之间的内在关系至关重要。最近我们构建了一系列基于荧光聚合物的分子温度计并应用于细胞内的温度变化研究。利用聚合物的温度刺激-响应性能引起键合于聚合物链上荧光分子的变化,可以高效灵敏的识别细胞内温度并实现其变化研究。同时,利用这种方法还可以进行外界刺激条件下细胞内温度变化成像,考察与温度相关的神经递质及能量物质的变化关系。

洋葱细胞骨架制备条件优化及影响因素研究

以洋葱为材料,研究1%Triton X-100抽提非骨架蛋白时间、细胞环境温度和紫外线照射活细胞对洋葱细胞骨架形态观察效果的影响。结果表明:1%Triton X-100抽提非骨架蛋白25 min观察效果较好,细胞处在20℃和4℃环境下骨架清晰完整,呈网络状分布;-18℃、50℃及紫外线照射60 min处理均会造成细胞骨架不同程度的解聚,影响细胞骨架的观察。

纳米温度计

日前，美国普林斯顿大学和加州大学伯克利分校共同开发成功一种能测量人体单个细胞温度的纳米温度计。该温度哥用镉和硒的量子点制成，小到足以进入单个细胞。当温度变化时，这些量子点就会发射出不同颜色的光，通过专门的仪暑对这些光进行“解码”就能发现细胞的温度变化。

磁学温度成像方法

随着生物医学的快速发展,细胞层面的生物信息检测成为生命科学研究的迫切需求。温度作为反应生物体活动状态的基本物理量,其检测技术近年来发展迅速。主要介绍了磁学温度成像技术的实现方式及各种实现方式的优势和缺点,最后,讨论了基于超顺磁性纳米粒子的温度成像技术有望实现细胞尺寸的高灵敏温度成像。

Investigation on the Sterility Changeover of Male Sterility Line CMS7311 in Heading Chinese Cabbage

Sterility changeover induced by low temperature in male sterility line CMS7311 of heading Chinese cabbage ( Brassica campestris L. ssp. penkinsis) was investigated under constant temperature, day/night alternating temperature in light-growth-incubator and outdoor natural day/night alternating temperature respectively. It showed that the sterility of CMS7311 has significant change with temperature. The constant temperature of 6 - 12 degreesC was suitable to induce the changeover of sterility (CGS) of CMS7311 ; the shortest treatment time for CGS induction at this temperature was 3 d. The significant value of sterility changeover of CMS7311 occurred at the constant temperature of 6 - 9 degreesC after treatment for 6 - 9 d. The intensity of CGS was stronger under constant temperature than under alternate temperature, but the shortest treatment time inducing CGS has no difference between them. When treated for 9 d under the day/night alternating temperature of 11/7 degreesC, its sterility could also turn to normal fertility (near to sterile grade I or zero). In normal condition, the interval from the end of temperature treatment to the beginning of CGS induction was 10 - 16 d. In the condition of natural day/night alternating temperature, the lower limit of temperature for effective CGS induction was at the daily mean temperature ( DMT) of 3. 5 - 6. 8 degreesC, and the shortest treatment time which could induce the sterility changeover was also longer than that under constant temperature, being 11d at DMT of 1.5 - 3.1 degreesC. In addition, for the apical dominance, the flower bud on the first lateral branch showed the CGS 8 - 10 d later than the flower bud on the main stem under the same temperature with the same days of treatment. The intensity of CGS of CMS7311 on the first lateral branch was also weaker than the flower bud on the main stem.

Quantum fluctuations of mesoscopic biological cell at finite temperature

On the basis of the quantization of mesoscopic biological cell equivalent circuit,we studied the quantum fluctuations of voltage and current of mesoscopic biological cell equivalent circuit as finite temperature by Bogoliuov transformation.The result shows that the quantum fluctuations of voltage and current not only relate with the parameters of equivalent circuit,temperature,but also decay with time.This result may have significant value on the design and application of the bio-electronic apparatus.

Intracellular temperature measurement by a dual-thermocouple difference method

A dual thermocouple difference technique is developed to determine the accuracy and anti-interference ability in the process of intracellular temperature measurement.First,two micro-nano thermocouples(TC)and a high-precision signal acquisition module are used to measure the temperature difference between the cell and the culture medium(separated about 10μm from the cell).The cold junctions of two TCs are connected to eliminate the setting of the reference temperature and enhance the anti-interference ability.Then,a low-noise voltage amplifier and digital acquisition card are used to sample signals.In order to verify the feasibility of the dual thermocouple difference method,the temperature changes of U251 cells are detected.The calibration results of two TCs show that the Seebeck coefficient is about 5μV/℃,and the signal acquisition accuracy is 0.5μV in a low voltage range(0-15μV).With the dual thermocouple difference method,errors due to the cold junctions can be removed and the interference caused by environmental temperature fluctuation can be reduced.The phenomenon of cellular temperature increase proves that the dual thermocouple difference method can detect the tiny temperature change of a single cell.The method potentially is a highly powerful technique for studying local thermogenesis of cells and helps to explore the relationship between cellular thermogenesis and cellular processes.

Effect of Low-pressure Carbonation on the Heat Inactivation and Cytoplasmic Acidification of Saccharomyces cerevisiae

Effect of low-pressure carbonation （LPC） on heat inactivation of Saccharomyces cerevisiae was investigated. The cell suspension was carbonated at 1 MPa and 4℃ for 15 min and subsequently heated from 51 to 61 ℃ and 5 s to 5 min （heating with LPC）. As a control experiment, cell suspension was heat-treated under atmospheric pressure without LPC （heating）. The inactivation ratio of heating at 53℃ and 55℃ for l rain with LPC was approximately 1 log order higher than heating alone. Extending heating time to 5 min did not widen the difference in the inactivation ratio between heating with LPC and heating alone at both heating temperatures. At 57℃, the difference in inactivation ratio increased from 1 to 2.5 log order with extending treatment time from 5 to 15 s. The results suggested that the enhanced inactivation effect by LPC was obtained at the higher temperature with short time treatment than the lower temperature with longer time treatment. Under fluorescence microscope observation of LPC-treated cell stained with LysoSensor probe, it seemed that LPC was hardly able to acidify the cytoplasm ofS. cerevisiae. It is considered that the ability orS. cerevisiae ceils to keep their cytoplasmic pH during LPC resulted in the inferior increase in heat inactivation ratio by LPC as compared with bacteria in the previous studies.

Simulation of stray grain formation during unidirectional solidification of IN738LC superalloy

The influence of casting parameters on stray grain formation of a unidirectionally solidified superalloy IN738LC casting with three platforms was investigated by using a 3D cellular automaton-finite element （CAFE） model in CALCOSOFT package. The model was first validated by comparison of the reported grain structure of AI-7%Si （mass fraction） alloy. Then, the influence of pouring temperature, heat flux of the lateral surface, convection heat coefficient of the cooled chill and mean undercooling of the bulk nucleation on the stray grain formation was studied during the unidirectional solidification. The predictions show that the stray grain formation is obviously sensitive to the pouring temperature, heat flux and mean undercooling of the bulk nucleation. However, increasing the heat convection coefficient has little influence on the stray grain formation.

Numerical Simulation of Effects of Cloud Top Temperatures and Generating Cells on Secondary Ice Production in Stratiform Clouds with a Detailed Microphysical Model

This paper outlines a one-dimensional,heightdependent bin model with detailed microphysical processes in which ice splinters are produced by a riming process.The model is then applied to simulate the shift of particle size distribution effected by the secondary ice production process within clouds with different generating cells and cloud top temperatures.The result of model simulations reveals the general effects of cloud updrafts on increasing ice particle concentration by extending the residence time of ice particles in clouds and providing sufficiently large supercooled water droplets.The rimesplintering mechanism is more effective in clouds with lower ice seeding rates than those with higher rates.Evolutions of hydrometeor size distribution triggered by the rime-splintering mechanism indicate that the interaction between large ice particles and supercooled water drops adds a "second maximum" to the primary ice spectra.

Temperature dependent expression of cdc2 and cyclin B1 in spermatogenic cells during spermatogenesis

p34cdc2 and Cyclin B1 are key components of cell cycle controlling machine and are believed to play a fundamental role in gametogenesis. It is also well known that, in scrotal mammals, spermatogenesis depends greatly on the maintenance of comparatively low temperature in the scrotum. To investigate whether the expression of cdc2 and Cyclin B1 in spermatogenic cells during spermatogenesis is actually a temperature dependent event, in situ hybridization, Western blotting and immunohistochemistry analysis were used to study the expression of cdc2 and Cyclin B1 in normal and cryptorchid testis. Results showed that the abdominal temperature had no significant influence on the transcription of cdc2 and Cyclin B1 in the spermatogonia and pachytene/diplotene primary spermatocytes, but it blocked the translation of them. Due to the deficiency of p34cdc2 and Cyclin B1, the spermatogonia and pachytene/diplotene primary spermatocytes were unable to form MPF, hence, they couldn’t undergo karyokinesis. The development of primary spermatocytes was arrested at the G2 to M phase transition. We also found that testosterone could regulate the Cyclin B1 expression in spermatogenic cells. Muscular injection of testosterone could recover spermatogenesis in the unilateral scrotal testis which was influenced by the contralateral cryptorchid testis, but it could not salvage the spermatogenesis block in the cryptorchid testis.

EFFECTS OF INFLAMMATORY CELLS IN COLD AND WARM ISCHEMIA-REPERFUSION INJURY OF THE GRAFTED LIVER

Objective To investigate whether the impairment of grafted livers after transplantation was induced by the same inflammatory cells both in cold and warm ischemia. Methods Male SD rats were divided into two groups at random,24 donor livers in each group were stored in Ringers solution at 4℃ for 120min or 240min of transplantation for blood sample and tissue specimen collection. Results Along with the prolongation of cold and warm ischemia time,the serum ALT,AST and LDH level increased gradually after transplantation.Under light microscopy,some hepatocytes presented necrosis after 3h and 6h of transplantation in cold ischemia,and neutrophilic infiltration in sinusoids were evident.Also,a large number of hepatocytes were necrotic 3h or 6h after transplantation in warm ischemia from NHBDs,and lymphocytic infiltration was evident in the sinusoids.The findings in electron microscopy was as the same as those of light microscopy,and the cells which infiltrated the sinusoids in warm ischemia were identified as T lymphocytes. Conclusion The impairment of grafted livers after transplantation appeared to be induced by two different kinds of inflammatory cells in cold and warm ischemia,that is,neutrophils mediated the cold ischemia-reperfusion,and T lymphocytes mediated the warm ischemia-reperfusion from NHBDs,but these findings are to be comfirmed in further investigations.

Analytical Behavior of Fura-2 and Its Determination of [Ca2+]i in Lymphocytes Treated with Cefotaxime

The interaction of Fura-2 with Ca^2＋ is studied using steady fluorescence technique. The effect of pH on the spectra behavior of Fura-2 in the presence of Ca^2＋ is investigated, the excitation maxima （340 nm） and the isobestic point （360 nm） for the fluorescence spectra of Fura-2 depend on pH. At different temperatures the apparent dissociation constants （ Kd ） of Fura-2-Ca^2＋ complex are examined, Kd is found to decrease with increasing temperatures （20 ℃, 37 ℃, 50 ℃ ） and △His calculated to be 21.16 kJ/mol by using the Van＇ t Hoff equation at pH 7.4 for all the temperatures tested. The determination of intracellular Ca^2＋ concentration （ [Ca^2＋ ] i ） in lymphocyte is developed by using Fura-2 as a fluorescence probe in the presence of Cefotaxime at 37 ℃ and pH 7.4.

‘Initial’ Soil Moisture Effects on the Climate in China——A Regional Climate Model Study

In this study,the effects of ‘initial’ soil moisture(SM) in arid and semi-arid Northwestern China on subsequent climate were investigated with a regional climate model. Besides the control simulations(denoted as CTL),a series of sensitivity experiments were conducted,including the DRY and WET experiments,in which the simulated ‘initial’ SM over the region 30 –50°N,75 –105°E was only 5% and 50%,and up to 150% and 200% of the simulated value in the CTL,respectively. The results show that SM change can modify the subsequent climate in not only the SM-change region proper but also the far downstream regions in Eastern and even Northeastern China. The SM-change effects are generally more prominent in the WET than in the DRY experiments. After the SM is initially increased,the SM in the SM-change region is always higher than that in the CTL,the latent(sensible) heat flux there increases(decreases),and the surface air temperature decreases. Spatially,the most prominent changes in the WET experiments are surface air temperature decrease,geopotential height decrease and corresponding abnormal changes of cyclonic wind vectors at the mid-upper troposphere levels. Generally opposite effects exist in the DRY experiments but with much weaker intensity. In addition,the differences between the results obtained from the two sets of sensitivity experiments and those of the CTL are not always consistent with the variation of the initial SM. Being different from the variation of temperature,the rainfall modifications caused by initial SM change are not so distinct and in fact they show some common features in the WET and DRY experiments. This might imply that SM is only one of the factors that impact the subsequent climate,and its effect is involved in complex processes within the atmosphere,which needs further investigation.