Bardet-Biedl syndrome: an emerging pathomechanism of intracellular transport

From a handful of uncloned genetic loci 6 years ago, great strides have been made in understanding the genetic and molecular aetiology of Bardet-Biedl syndrome (BBS), a rare pleiotropic disorder characterised by a multitude of symptoms, including obesity, retinal degeneration and cystic kidneys. Presently, 11 BBS genes have been cloned, with the likelihood that yet more BBS genes remain undiscovered. In 2003, a major breakthrough was made when it was shown that BBS is likely caused by defects in basal bodies and/or primary cilia. Since then, studies in numerous animal models of BBS have corroborated the initial findings and, in addition, have further refined the specific functions of BBS proteins. These include roles in establishing planar cell polarity (noncanonical Wnt signaling) in mice and zebrafish, modulating intraflagellar transport and lipid homeostasis in worms, and regulating intracellular trafficking and centrosomal functions in zebrafish and human tissue culture cells. From these discoveries, a common theme has emerged, namely that the primary function of BBS proteins may be to mediate and regulate microtubule-based intracellular transport processes. Received 20 April 2006; received after revision 30 May 2006; accepted 15 June 2006     

Intracellular transport by motor proteins with the same directionality

Active intracellular transport is mainly performed by a group of special nanomachines called motor proteins. During transport, cooperation between motor proteins significantly influences important transport features, such as distance and velocity. To understand this mechanism, we combine Gillespie simulation and analytical derivation to demonstrate how the mechanical properties of a single motor influence the cooperation between multiple motors, further regulating the transport distance. In addition, we build a deep learning model to help us quickly obtain the motor parameters. Our results shed light on the physical nature of intracellular transport by motor proteins with the same directionality.     

猪传染性胃肠炎病毒S基因B和C抗原位点片段在昆虫细胞中的胞内表达

通过基因重组的方法,在昆虫细胞胞内表达了猪传染性胃肠炎病毒（TGEV）S基因B和C抗原位点片段.表达蛋白经Dot-ELISA检测具有良好的抗原性.本研究为TGEV的血清学检测方法的建立提供了必要的物质基础.     

Induction of vanadium accumulation and nuclear sequestration causing cell suicide in human Chang liver cells

Very little is known about the modulation of vanadium accumulation in cells, although this ultratrace element has long been seen as an essential nutrient in lower life forms, but not necessarily in humans where factors modulating cellular uptake of vanadium seem unclear. Using nuclear microscopy, which is capable of the direct evaluation of free and bound (total) elemental concentrations of single cells we show here that an NH₄Cl acidification prepulse causes distinctive accumulation of vanadium (free and bound) in human Chang liver cells, concentrating particularly in the nucleus. Vanadium loaded with acidification but leaked away with realkalinization, suggests proton-dependent loading. Vanadyl(4), the oxidative state of intracellular vanadium ions, is known to be a potent source of hydroxyl free radicals (OH^.). The high oxidative state of nuclei after induction of vanadyl(4) loading was shown by the redox indicator methylene blue, suggesting direct oxidative damage to nuclear DNA. Flow cytometric evaluation of cell cycle phase-specific DNA composition showed degradation of both 2N and 4N DNA phases in G₁, S and G₂/M cell cycle profiles to a solitary 1N DNA peak, in a dose-dependent manner, effective from micromolar vanadyl(4) levels. This trend was reproduced with microccocal nuclease digestion in a time response, supporting the notion of DNA fragmentation effects. Several other approaches confirmed fragmentation occurring in virtually all cells after 4 mM V(4) loading. Ultrastructural profiles showed various stages of autophagic autodigestion and well defined plasma membrane outlines, consistent with programmed cell death but not with necrotic cell death. Direct intranuclear oxidative damage seemed associated with the induction of mass suicide in these human Chang liver cells following vanadium loading and nuclear sequestration.     

中国蜉蝣科（昆虫纲：蜉蝣目）研究

报导中国蜉蝣科共２属３１种，其中伊蜉属（Ｅａｔｏｎｉｇｅｎｉａ）为新记录属；查氏伊蜉（Ｅａｔｏｎｉｇｅｎｉａｃｈａｐｅｒｉ）和萨夏林蜉（Ｅｐｈｅｍｅｒａｓａｃｈａｌｉｎｅｎｓｉｓ）为新记录种；毛阳蜉（Ｅｐｈｅｍｅｒａｍａｏｙａｎｇｅｎｓｉｓｓｐ．ｎｏｖ．）、尖岭蜉（Ｅｐｈｅｍｅｒａｊｉａｎｆｅｎｇｅｎｓｉｓｓｐ．ｎｏｖ．）、万泉蜉（Ｅｐｈｅｍｅｒａｗａｎｑｕａｎｅｎｓｉｓｓｐ．ｎｏｖ．）、海南蜉（Ｅｐｈｅｍｅｒａｈａｉｎａｎｅｎｓｉｓｓｐ．ｎｏｖ．）、洪江蜉（Ｅｐｈｅｍｅｒａｈｏｎｇｊｉａｎｇｅｎｓｉｓｓｐ．ｎｏｖ．）、徐氏蜉（Ｅｐｈｅｍｅｒａｈｓｕｉｓｐ．ｎｏｖ．）、张家界蜉（Ｅｐｈｅｍｅｒａｚｈａｎｇｊｉａｊｉｅｅｎｓｉｓｓｐ．ｎｏｖ．）、湖南蜉（Ｅｐｈｅｍｅｒａｈｕｎａｎｅｎｓｉｓｓｐ．ｎｏｖ．）等８种为新种，并对其形态特征进行详细描述．蜉蝣属种类居世界之首．     

平衡冷冻后红细胞胞内未冻水的状态

基于Boyle—Van’t Hoff关系设计了2种独立的实验方案，研究了红细胞内束缚水的状态．第一种方案使用电子粒子计数仪(EPC)测定了室温下在不同浓度的NaCl溶液中取得渗透平衡的红细胞的体积(V)，其中包括红细胞的等渗体积V0(与0．9％的NaCl溶液取得渗透平衡的红细胞体积)．第二种方案使用差示扫描量热仪(DSC)测定了不同压积比的红细胞悬液慢速冷冻的放热量．通过理论模型计算，进一步得到红细胞的最终平衡体积(Hf)．平衡冷冻的最终体积与细胞内非渗透性体积(Vb)存在差别，这一差别被认为是细胞内束缚水的体积．实验结果表明：(1)两种实验方法等效；(2)平衡冷冻后胞内几乎没有自由水，亦即红细胞内束缚水只有一种状态，为结合水．     

盐胁迫对鲁氏酵母菌生理特性的影响

研究了盐胁迫对鲁氏酵母菌(Zygosaccharomyces rouxii CGMCC 3791)细胞生理特性的影响,结果表明,盐胁迫使细胞生长受到抑制,单位(每克)菌体乙醇含量从11.64mg增加到19.20mg(120g/L NaCl)。分析细胞胞内pH值和胞内活性氧(ROS)水平,结果表明:盐胁迫使细胞胞内pH值水平降低,胞内活性氧(ROS)水平增加,同时胞内抗氧化酶系(过氧化氢酶、超氧化物歧化酶、过氧化物酶,以及谷胱甘肽过氧化物酶)的活力提高,从而抵御由盐胁迫引起的氧胁迫。研究了盐胁迫对鲁氏酵母菌胞内谷胱甘肽(GSH)含量的影响,结果表明,随着盐质量浓度增加,胞内GSH含量增加,在120g/L盐质量浓度下,GSH含量显著增加了73.4%。考察了外源添加GSH对细胞生长的影响,发现添加0.5g/L GSH的鲁氏酵母菌,在120g/L盐质量浓度下生物量提高了15%。本研究可对深入认识鲁氏酵母菌耐盐生理机制及进一步提高其耐盐性能提供理论支持。     

Calculation of the intracellular elastic modulus based on an atomic force microscope micro-cutting system

Better understanding of variations in the mechanical properties of cancer cells could help to provide novel solutions for the diagnosis,prevention,and treatment of cancers.We therefore developed a calculation model of the intracellular elastic modulus based on the contact pressure between the silicon tip of an atomic force microscope and the target cells,and cutting depth.Ovarian cells(UACC-1598) and colon cancer cells(NCI-H716) were cut into sequential layers using an atomic force microscope silicon tip.The cutting area on the cells was 8μm×8μm,and the loading force acting on the cells was increased from 17.523 to 32.126μN.The elastic modulus distribution was measured after each cutting process.There were significant differences in contact pressure and cutting depth between different cells under the same loading force,which could be attributed to differences in their intrinsic structures and mechanical properties.The differences between the average elastic modulus and surface elastic modulus for UACC-1598 and NCI-H716 cells were 0.288±0.08 kPa and 0.376±0.16 kPa,respectively.These results demonstrate that this micro-cutting method can be used to measure intracellular mechanical properties,which could in turn provide a more accurate experimental basis for the development of novel methods for the diagnosis and treatment of various diseases.     

Synkinesis in hemifacial spasm: results of recording intracranially from the facial nerve

Summary We show evidence that the motonucleus of the facial nerve is involved in producing the synkinesis in patients with hemifacial spasm. These results were obtained by recording from the intracranial portion of the facial nerve and from the orbicularis oculi muscle in patients operated upon for hemifacial spasm during electrical stimulation of the mandibular branch of the facial nerve. Also, the electromyographic response from the same muscle was recorded when the facial nerve was electrically stimulated at a location near the brainstem. The results show that it is unlikely that the symptoms of patients with hemifacial spasm can be explained on the basis of ephaptic transmission at the site of lesion of the facial nerve.