An in vitro neurite-promoting antigen functions in axonal regeneration in vivo

The function of the neurite growth-promoting antigen INO has been tested in an in vivo neurite regeneration system, the rat iris. The sympathetic innervation of the irides was removed by a single systemic injection of 6-hydroxydopamine. The subsequent regeneration of sympathetic axons into the iris of one eye bathed by the INO antibody, which inhibits neurite growth in vitro, was compared with the regrowth of sympathetic axons into the iris of the animal's other eye, which contained control antibody. Antibodies were released within the eye by implanted hybridoma cells. Neurite regeneration was measured by assaying [3H]norepinephrine uptake into freshly explained irides. The blockage of the function of the INO antigen by the antibody resulted in a decreased rate of axonal regeneration, thus suggesting the involvement of the INO antigen in the process of neurite regeneration in vivo.     

Promoting axon regeneration in the adult CNS by modulation of the PTEN/mTOR pathway

The failure of axons to regenerate is a major obstacle for functional recovery after central nervous system (CNS) injury. Removing extracellular inhibitory molecules results in limited axon regeneration in vivo. To test for the role of intrinsic impediments to axon regrowth, we analyzed cell growth control genes using a virus-assisted in vivo conditional knockout approach. Deletion of PTEN (phosphatase and tensin homolog), a negative regulator of the mammalian target of rapamycin (mTOR) pathway, in adult retinal ganglion cells (RGCs) promotes robust axon regeneration after optic nerve injury. In wild-type adult mice, the mTOR activity was suppressed and new protein synthesis was impaired in axotomized RGCs, which may contribute to the regeneration failure. Reactivating this pathway by conditional knockout of tuberous sclerosis complex 1, another negative regulator of the mTOR pathway, also leads to axon regeneration. Thus, our results suggest the manipulation of intrinsic growth control pathways as a therapeutic approach to promote axon regeneration after CNS injury.     

辛伐他汀通过激活p38MAPK信号通路促进MC3T3-E1细胞增殖的研究

为研究辛伐他汀通过激活p38MAPK信号通路对小鼠胚胎成骨前体细胞(MC3T3-E1)增殖的影响,将试验分为2个部分:①将辛伐他汀作用于MC3T3-E1细胞,设置不同的辛伐他汀浓度和作用时间,采用pNPP、CCK8方法检测细胞碱性磷酸酶(ALP)活性并得到辛伐他汀对MC3T3-E1细胞增殖作用的最适浓度和最佳培养时间....     

EGFR和K-Ras在上皮性卵巢癌组织中的表达及临床意义

\t\t\t\t\t目的\t\t\t\t\t探讨促卵泡激素受体结合抑制剂(FRBI)对绵羊卵母细胞中K-Ras、c-Myc及FSHR mRNA和蛋白质水平的影响,进一步阐明FRBI是否通过IP3信号通路发挥作用。\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t方法\t\t\t\t\t将卵母细胞置于10 IU/mL的FSH和不同质量浓度FRBI (0、10、20、30和40 μg/mL)的体外成熟培养基中培养24 h。应用ELISA检测IVM培养液中K-Ras、c-Myc、cAMP、FSH和IP3的含量。qRT-PCR和Western-blot检测卵母细胞中FSHR mRNA和蛋白质的水平。\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t结果\t\t\t\t\t至24 h时,随着FRBI剂量增加,COM-1组至COM-3组c-Myc质量浓度逐渐降低,COM-3显著低于FSH组(P<0.05),COM-4组24 h的K-Ras质量浓度显著低于阴性对照组(CG)和FSH组(P<0.05);COM组中,FSHR mRNA和蛋白表达水平随着FRBI剂量的增加而下降,高剂量组(COM-4) mRNA与蛋白质表达水平显著低于FSH组(P<0.05)。cAMP和IP3含量随FRBI剂量增加而递减,COM-4组IP3显著低于CG组(P<0.05)。\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t结论\t\t\t\t\t在FSH存在下,FRBI可减少K-Ras和c-Myc的产生,抑制卵母细胞的FSHR水平,FRBI可能通过IP3通路发挥作用。\t\t\t\t     

Reversal of the TCR stop signal by CTLA-4

The coreceptor cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) is pivotal in regulating the threshold of signals during T cell activation, although the underlying mechanism is still not fully understood. Using in vitro migration assays and in vivo two-photon laser scanning microscopy, we showed that CTLA-4 increases T cell motility and overrides the T cell receptor (TCR)-induced stop signal required for stable conjugate formation between T cells and antigen-presenting cells. This event led to reduced contact periods between T cells and antigen-presenting cells that in turn decreased cytokine production and proliferation. These results suggest a fundamentally different model of reverse stop signaling, by which CTLA-4 modulates the threshold for T cell activation and protects against autoimmunity.     

接种方式对大白菜下胚轴离体不定芽再生及生理指标的影响

以大白菜品种‘贵龙5号’的下胚轴为材料,以3种不同方式接种,观察不定芽分化情况,并比较不同接种方式的下胚轴不定芽再生过程中可溶性蛋白质含量、过氧化物酶(POD)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性的变化。结果表明,以正插(形态学下端插入培养基)方式接种的下胚轴在接种8~10 d时不定芽开始产生,不定芽分化率达87.8%,平均每外植体再生的不定芽数为15.1个,其不定芽再生能力显著大于反插(形态学上端插入培养基)和平放的外植体;下胚轴在不定芽分化过程中各生理指标呈现规律性的变化,可溶性蛋白质含量、POD和SOD活性在芽原基形成以前表现出上升趋势而CAT活性下降,不定芽分化后呈相反变化趋势;不同接种方式的下胚轴在不定芽发生过程中各生理指标的变化有一定差异。以上结果表明大白菜下胚轴不定芽发生过程中形态学变化和生理变化紧密相关。     

Acute axonal dystrophy caused by fluorocitrate: the role of mitochondrial swelling

Fluorocitrate, a Krebs cycle inhibitor, induices neurons to rapidly expel multitudinous lysosomes, mitochondria, and other cytoplasmic constituents into their axons. After convulsive seizures commence, spectacular axonal balloons develop owing to obstruction of axonal flow by "log jams" of extruded organelles. A swelling of neuronal mitochondria is apparently responsible for the disgorgement of cytoplasmic material into axons.     

Retrograde axonal transport in the central nervous system

When horseradish peroxidase is injected into the optic tectum of a chick, axons of ganglion cells transport it centripetally to their cell bodies in the retina at a rate of about 72 millimeters per day. After intraocular injections in the young chick, the peroxidase is transported centripetally along efferent axons, and is concentrated in cell bodies within the isthmo-optic nucleus. This retrograde movement of protein from axon terminal to cell body suggests a possible mechanism by which neurons respond to their target areas.     

Surface areas of the cerebral cortex of mammals determined by stereological methods

The surface areas of the cerebral cortex excluding archipallium of 20 human, 11 cetacean, 6 carnivore, and 5 marsupial brains were determined by stereological methods. There exist rather strict relationships between volume, length of superficially exposed gyri, and cortical surface area.     

Metabolism of rotenone in vitro by tissue homogenates from mammals and insects

Hydroxylation of rotenone in vitro in the enzyme system composed of microsomes and reduced nicotinamide-adenine dinucleotide phosphate, and in living mice and houseflies, yields products tentatively identified as rotenolone I; rotenolone II; 8'-hydroxyrotenone; 6',7'-dihydro-6',7'-dihydroxyrotenone; two rotenolones of each of the last-mentioned two compounds; and uncharacterized polar materials. The toxicity of certain of these rotenoids to mice is of the same order as that of rotenone.     

Induction of follicle separation in the mosquito by physiological amounts of ecdysterone

Physiological quantities of the molting hormone, ecdysterone, injected into female Aedes aegypti prematurely induced separation of incipient follicles in the ovarioles, an event that normally occurs only in blood-fed females. It was possible to stimulate this morphological event with physiological amounts of hormone by mimicking, with two injections, the timing of normal increases in endogenous hormone of blood-fed females.     

Quantitative analysis of evolution of the brain in mammals

Empirical equations derived from brain size (E) and body size (P) of archaic-Eocene, Oligocene, and Recent mammals were all of the form, E = kP(2/3); k = 0.03 for the Eocene, 0.06 for the Oligocene, and 0.12 for the Recent groups. It is suggested that k, which has been used as an index of cephalization in contemporary mammals, may be an appropriate measure of brain evolution in the mammals as a class.     

哺乳动物性腺特异表达基因研究进展

在哺乳动物配子发生过程中,需要一个严格的阶段性和细胞特异性的基因表达程序。近年来,随着基因克隆、表达及功能研究技术的发展与应用,发现了许多配子发生过程中发挥特定作用的阶段特异和细胞特异表达的基因,有的已被证明在配子发生中起重要作用,但生殖细胞在分化及发育时受其调节的分子机制尚未了解,需要进行更加广泛深入的研究。文章综述了动物性腺特异表达基因研究的最新进展,旨在为从事该领域研究的工作者提供参考信息。     

Genetic variation in social mammals: the marmot model

The social substructure and the distribution of genetic variation among colonies of yellow-bellied marmots, when analyzed as an evolutionary system, suggests that this substructure enhances the intercolony variance and retards the fixation of genetic variation. This result supports a traditional theory of gradual evolution rather than recent theories suggesting accelerated evolution in social mammals.     

Retrograde axonal transport of endogenous proteins in sciatic nerve demonstrated by covalent labeling in vivo

Extracellularly applied N-succinimidyl [2,3-3H]propionate was used in vivo to covalently label intra-axonal proteins in the rat sciatic nerve. This technique permitted a unique view of axonal transport of proteins independent of biosynthesis. The proteins detected in slow anterograde transport (1 to 2 millimeters per day) correspond to cytoskeletal proteins described in previous papers. The slowly retrogradely transported component (3 to 6 millimeters per day) was composed primarily of a single protein with a molecular weight of 68,000.     

Calibration of the beginning of the age of mammals in patagonia

Beds of the Rio Chico Formation containing the earliest known land mammals in Patagonia, southern Argentina, were calibrated by potassium-argon age determinations and paleomagnetic polarity data. The Riochican land mammal age encompasses the middle and late Paleocene and corresponds in time with Torrejonian and Tiffanian land mammal faunas in North America.     

Laonastes and the "Lazarus effect" in recent mammals

The living Laotian rodent Laonastes aenigmamus, first described in early 2005, has been interpreted as the sole member of the new family Laonastidae on the basis of its distinctive morphology and apparent phylogenetic isolation from other living rodents. Here we show that Laonastes is actually a surviving member of the otherwise extinct rodent family Diatomyidae, known from early Oligocene to late Miocene sites in Pakistan, India, Thailand, China, and Japan. Laonastes is a particularly striking example of the "Lazarus effect" in Recent mammals, whereby a taxon that was formerly thought to be extinct is rediscovered in the extant biota, in this case after a temporal gap of roughly 11 million years.     

Polyol pathway in aorta: regulation by hormones

Aldose reductase is present in human and rabbit aortas and provides a mechanism whereby hyper-glycemia can alter the metabolism of the arterial wall. Aortic sorbitol concentration is regulated by ambient glucose concentration and is increased by epinephrine, isoproterenol, dibutyryl-3',5'-adenosine monophosphate, ouabain, and angiotensin II.     

利用正交设计优化甘蓝型油菜高频再生体系

采用L16(45)正交试验比较了BAP、NAA、AgNO3、蔗糖和外植体等5因素对甘蓝型油菜离体再生的影响,结果表明:BAP为甘蓝型油菜再生频率最主要的影响因素,其次依次为外植体、NAA和AgNO3,蔗糖对其影响不显著.结果显示,MS BAP 4 mg/L NAA 0.3 mg/L AgNO3 2.5 mg/L 2%蔗糖 0.8%琼脂为培养基,以带柄子叶为外植体的甘蓝型油菜再生体系的再生频率最高,达到94.45%.     

春玉米不同生育时期干旱对主要生理参数的影响

通过对黑龙江省春玉米干旱过程中的几个相关生理参数(叶绿素含量、硝酸还原酶活性和光合速率)的测定及分析发现,春玉米不同生育时期对水分胁迫的反应不同。苗期抗旱性较强,孕穗期到开花期对水分胁迫最敏感。干旱情况下,叶绿素a和总叶绿素含量在孕穗期降解最快;而叶绿素b含量在拔节期降解最快;硝酸还原酶活性在抽雄期降低幅度最大,达38.39%;光合速率在孕穗期降低幅度最大,达59.88%。