Conservation of endocochlear potential in mice with profound hearing loss induced by co-administration of kanamycin and furosemide

Research in mammalian hair cell regeneration is hampered by a lack of in vivo model of adult mouse inner ear injury. In the present study we investigated the effects of a combination of a single dose of aminoglycoside followed by a loop diuretic in adult mice. The auditory brainstem response threshold shift, extent and defining characteristics of the cochlear lesion were assessed and verified at different time points post-treatment. Our data indicated that this drug combination caused the rapid and extensive death of outer hair cells (OHCs). OHC death presented throughout the cochlea that commenced in the basal turn by 24 h and progressed apically. In contrast, inner hair cell (IHC) loss was delayed and mild. Terminal deoxynucleotidyl transferase dUTP nick end labelling-positive nuclei demonstrated that the majority of OHCs died via an apoptotic pathway. Auditory threshold shifts of up to 90 dB SPL indicated a profound hearing loss. In addition, the endocochlear potential (EP) in the drug-treated animals displayed a significant decline at 12 h post-treatment followed by recovery by 48 h post-treatment. Despite this recovery, there was a significant and progressive decrease in strial vascularis thickness, which was predominantly due to atrophy of marginal cells. The present study reproduced an adult mouse model of aminoglycoside-induced hearing loss. The mechanism underlying the recovered EP in the model with extensive hair cell death is discussed.     

黄杨绢野螟滞育诱导及光温反应

为了探讨黄杨绢野螟Diaphania perspectalis(Walker)越冬滞育特性,在自然条件与室内恒温下对黄杨绢野螟滞育诱导的光周期反应与光敏感龄期进行了研究。结果表明:该虫的光周期反应属于长光照反应型,短光照是引起黄杨绢野螟幼虫滞育的主要因子。幼虫的光周期反应对温度敏感,在恒温25℃和28℃条件下,诱导滞育的临界光周期分别为13h36min和12h50min。在日平均温度为26.7℃条件下,诱导滞育的临界光周期为13h40min。在恒温25℃条件下的滞育敏感虫龄试验表明,2～3龄幼虫即孵化后4～9d的幼虫对光周期反应最敏感。     

Sonodynamic effects of hematoporphyrin monomethyl ether on CNE-2 cells detected by atomic force microscopy

Hematoporphyrin monomethyl ether (HMME) has been effectively used to treat solid tumors of some types. However, its application in nasopharyngeal carcinoma has not been studied yet. In this paper, the detailed sonodynamic effects of HMME‐SDT (sonodynamic therapy) on CNE‐2 cells including cell growth inhibition, apoptosis induction, and membrane toxicity were investigated. It was found that HMME alone had less cytotoxicity whereas HMME‐SDT could suppress the cell proliferation in a dose‐dependent manner as detected by MTT assay. The annexin V‐based flow cytometric data indicated that upon SDT, different concentrations of HMME induce distinct types of cell death, apoptosis by low concentration (60 µg/ml) of HMME and necrosis by higher concentration (120 µg/ml). The immunofluorescence of cytoskeleton and nuclei morphology showed that upon HMME‐SDT, the cells became rounding and the cytoskeletal network disappeared, and, the nuclei represented a total fragmented morphology of nuclear bodies. These alternations showed the apoptosis induction by HMME‐SDT. Further AFM study showed that the cell membrane structure and cytoskeleton networks were destroyed, and, the Young's modulus, tip‐cell‐surface adhesion force decreased to 0.22 ± 0.11 Mpa, 35.4 ± 12.8 pN of cells with 120 µg/ml HMME‐SDT from 0.48 ± 0.21 Mpa, 69.6 ± 22.3 pN of native cells, respectively. These membrane changes caused the collapse of mitochondrial transmembrane potential and disturbance of intracellular calcium homeostasis, which was consistent with the results detected by flow cytometry. Therefore, membrane toxicity and cytoskeleton disrupture induced by HMME‐SDT maybe important factors to induce cell apoptosis, and, the disturbance of mitochondrial transmembrane potential and calcium channels might be the apoptosis mechanisms. J. Cell. Biochem. 112: 169–178, 2011. © 2010 Wiley‐Liss, Inc.     

国产单叶蔓荆种内变异的数量分类学研究

分析了中国分布单叶蔓荆的种内变异.每个居群随机采取5个以上的完整植株,以16个居群单叶蔓荆作为分类运算单位(operational taxonomic unti,OTU),选取11个有变异的形态学性状和3个品质性状.形态性状以各植株的平均值作为OTUs的原始数据,形成16×14的原始数据矩阵,对矩阵进行聚类分析.根据Q...     

不同采收方式对富养化河道浮床空心菜生物产出的影响

以浮床空心菜为研究对象,在过水河道条件下,研究了不同采收周期(14 d采收1次、21 d采收1次、28 d采收1次)和留茬高度(15 cm、25 cm、35 cm)组合对浮床植物生物产出的影响.结果表明:刈割后的植物仍能够适应过水河道环境,并在其生长周期内持续生长.经110 d的生长,分枝数提高了近5倍,最长根长27.55 cm,平均根长15 cm,根系直径达11cm.单株根鲜重可达146 g,每平方米浮床根部可吸附颗粒物3.36 kg.新芽生长速率随采收次数增多,处理组均呈现先不断提高然后减小的趋势,变化幅度为0.54～3.7cm·d-1,对照组为1.63 cm·d-1.适当刈割能提高新芽再生速率.单次收获生物量同新芽变化规律相似,即先逐渐增多然后减小,生物量增长速率变化幅度3.83～37.9 g·m-2·d-1.从总生物量来看,28 d采收1次留茬25 cm、35 cm组的生物量(干重)产出最高,达2112 g·m-2;从茎叶比看,每14 d采收1次3个留茬高度,及每21d采收1次留茬15 cm和25 cm方式收获生物量茎叶比较佳.综合考虑产量、质量及浮床便捷管理,每21 d采收1次留茬15 cm的采收方式效果最佳,此时新芽平均生长速率1.88 cm·d-1,平均茎叶比＜1,总生物量1966 g·m-2.     

基于荧光检测的新型细胞传感器

主要介绍了一类基于荧光检测的新型细胞传感器,这类传感器利用免疫细胞表面分子特异性识别、结合抗原的特性和生物(或化学)发光技术,通过检测荧光信号在数分钟内达到检测病原体或其他抗原的目的.这类传感器的发光原理主要是利用钙离子敏感型化学荧光探针发光,如Fluo-4等,或钙离子敏感型发光蛋白发光,如水母发光蛋白、绿色荧光蛋白等.现在已经应用的主要是B细胞传感器和肥大细胞传感器.这类传感器具有灵敏度高、检测准确、反应速度快的优点.同时又存在交叉反应、细胞不易保存等不足之处.这类传感器在疾病诊断、环境监测、生物战剂检测等领域具有较大的应用前景.     

Enhancement of cell growth rate by light irradiation in the cultivation of Rhodotorula glutinis

A yeast, Rhodotorula glutinis, is regarded as a potential microbial oil producer, due to its high lipid content. The flask results of this study indicated that irradiation could increase the growth of R. glutinis compared to that of a batch without irradiation. Further 5-l fermenter results confirmed that irradiation could greatly enhance the cells’ growth rate and total lipid productivity. The maximum lipid productivity obtained in the fed-batch operation with 3 LED (light emitting diode) lamps was 0.39 g/l h as compared to 0.34 g/l h in the batch with 3 LED lamps and 0.19 g/l h in the batch without irradiation. Conclusively, the irradiation could significantly increase the cells’ growth rate, which, in turn, could be applied to the commercialized production of biodiesel from single cell oils.     

Discovery of new photoactivatable diaryltetrazoles for photoclick chemistry via 'scaffold hopping'

We report the discovery of two long-wavelength (365 nm) photoactivatable diaryltetrazoles through screening a small library of diaryltetrazoles that were designed using a ‘scaffold hopping’ strategy. A naphthalene-derived tetrazole showed excellent reactivity in the photoinduced cycloaddition reaction with methyl methacrylate under 365 nm photoirradiation in acetonitrile PBS buffer mixture. Besides, the brightly fluorescent pyrazoline cycloadducts that were formed further increase the potential utility of these new diaryltetrazoles as ‘photoclick’ reagents and as reporters in biological studies.