The neuroendocrine thymus: coexistence of oxytocin and neurophysin in the human thymus

Immunoreactive oxytocin and neurophysin were identified and measured by radioimmunoassay in human thymus extracts. Serial dilutions of extracts paralleled the appropriate standard curves. Thymus-extracted oxytocin and neurophysin eluted in the same positions as reference preparations on Sephadex G-75. Authenticity of oxytocin was confirmed by biological assay and high-performance liquid chromatography analysis. In most instances, thymus contents of oxytocin and neurophysin were far greater than those expected from known circulating concentrations and declined with increasing age. The molar ratio of oxytocin to neurophysin in thymus was similar to that found in the hypothalamo-neurohypophyseal system, which strongly suggested with the other data a local synthesis of oxytocin. These findings indicate the presence of neurohypophyseal peptides in the human thymus and further support the concept of a neuroendocrine function integrated in an immune structure.     

The life and death of "Bare" viscous bubbles

Air bubbles collect and explode at the surface of many viscous liquids, as observed with polymer foams, in glass furnaces, and during volcanic eruptions. The liquid film separating the bubble from bulk air can have a long lifetime (if it is viscous) even if it is not protected by a surfactant. These "bare" films display unusual dynamic behaviors in drainage and rupture. Two different model systems were studied: a polymer melt (silicone oil) and a molten (borosilicate) glass of comparable viscosity. Although the two systems differ greatly in their relaxation time, they are described by the same set of laws, which can be understood from a relatively simple hydrodynamic model.     

正在崛起的生命科学学院

生命科学学科是41世纪的主导学科，通过对河北农业大学生命科学学院的发展历程和现状分析，提出“以人才培养为基础，以学科建设为中心，教学和科研并重”的办院方针，不断优化教师队伍和科研队伍，根据社会需求适度扩大招生规模，加快人才培养步伐，最终实现为社会服务的发展设想。     

Reward timing in the primary visual cortex

We discovered that when adult rats experience an association between visual stimuli and subsequent rewards, the responses of a substantial fraction of neurons in the primary visual cortex evolve from those that relate solely to the physical attributes of the stimuli to those that accurately predict the timing of reward. In addition to revealing a remarkable type of response plasticity in adult V1, these data demonstrate that reward-timing activity-a "higher" brain function-can occur very early in sensory-processing paths. These findings challenge the traditional interpretation of activity in the primary visual cortex.     

鸭胸腺内Ghrelin免疫组织化学的定位分布及发育性变化

【目的】研究Ghrelin在鸭胸腺发育过程中的定位分布及变化规律,以期为进一步探讨Ghrelin对胸腺生理功能的影响提供形态学资料.【方法】选用不同发育阶段的天府肉鸭,胚胎期分7个组,即:14、16、18、20、22、24和26 d胚龄组;胚后期分12个组,即:新生雏、1、3、5、8、11、14、17、20、26、29和32周龄组.运用免疫组织化学技术及形态计量方法研究Ghrelin在鸭胸腺发育过程中的定位分布及变化规律.【结果和结论】Ghrelin免疫阳性细胞弥散分布于20 d胚龄至胚后32周龄的胸腺小叶皮质和髓质;阳性细胞呈圆形、卵圆形、星形或不规则形,主要为胸腺上皮细胞和巨噬细胞.阳性细胞数量在胚胎期无明显差异,在胚后胸腺继续发育期(新生雏~8周龄)和成熟期(11~17周龄)呈波浪状变化,在退化期(20~32周龄)呈下降趋势.说明在天府肉鸭胸腺个体发育中存在Ghrelin免疫阳性细胞,其数量表现出明显增龄变化特性,与胸腺退化密切相关.     

Clonal deletion versus clonal anergy: the role of the thymus in inducing self tolerance

During development in the thymus, T cells are rendered tolerant to self antigens. It is now apparent that thymocytes bearing self-reactive T cell receptors can be tolerized by processes that result in physical elimination (clonal deletion) or functional inactivation (clonal anergy). As these mechanisms have important clinical implications for transplantation and autoimmunity, current investigations are focused on understanding the cellular and molecular interactions that generate these forms of tolerance.     

Autophagic fungal cell death is necessary for infection by the rice blast fungus

Rice blast is caused by the fungus Magnaporthe grisea, which elaborates specialized infection cells called appressoria to penetrate the tough outer cuticle of the rice plant Oryza sativa. We found that the formation of an appressorium required, sequentially, the completion of mitosis, nuclear migration, and death of the conidium (fungal spore) from which the infection originated. Genetic intervention during mitosis prevented both appressorium development and conidium death. Impairment of autophagy, by the targeted mutation of the MgATG8 gene, arrested conidial cell death but rendered the fungus nonpathogenic. Thus, the initiation of rice blast requires autophagic cell death of the conidium.     

初情期山羊胸腺microRNAs的筛选

为分析初情期前和初情期雌性山羊胸腺中MicroRNA的差异表达情况,并探讨其在山羊初情期启动过程中所起的作用.对初情期前(n = 3)和初情期(n = 3)山羊的胸腺组织进行了 Solexa测序,采用GO富集和KEGG分析评估差异miRNA靶基因.在初情期前和初情期的山羊胸腺组织中检测到538个miRNA,其中64个miRNA显著差异表达.与初情期前的山羊胸腺样本相比,初情期胸腺样本中存在19个上调基因和45个下调基因.KEGG通路富集分析显示,差异miRNA靶基因主要富集在苯丙氨酸,酪氨酸和色氨酸的生物合成,丁螺菌素和新霉素的生物合成等通路以及胆碱能突触和过氧化物酶体增殖物激活受体(PPAR)等与初情期启动相关信号途径.结果提示胸腺中miRNA参与山羊初情期启动.     

Phase change and the regulation of developmental timing in plants

Plants produce different types of organs at different times in shoot development. Along with the major changes in organ morphology that take place during developmental transitions, more gradual patterns of variation occur. The identity of organs produced at a particular position on the shoot is determined by interactions between several independently regulated, temporally coordinated processes. Two of these processes are organ production and the specification of organ identity. Coordination of these processes is accomplished in part by a thermal clock and by signal transduction pathways that mediate the response of plants to light.     

Allograft survival: effect of antiserums to thymus glands and lymphocytes

Although antiserums to lymphocytes and thymus cells have similar effects on lymphocytes and thymocytes in vitro, the antiserum to thymus has more persistent lymphopenic effect in vivo and prolongs allograft survival time more markedly. Since only thymus glands of animals treated with antiserum to thymus showed depletion of small lymphocytes, antibody to thymic humoral factor may be operational.     

Mutator activity in maize: timing of its activation in ontogeny

Mutator activity in maize seems not to be active throughout the development of the plant, but to arise late in ontogeny, and to be developmentally rather than chronologically triggered.     

9 -tetrahydrocannabinol: dose-related effects on timing behavior in chimpanzee

Delta(9)-Tetrahydrocannabinol, at doses within the effective range for humans, was administered orally to chimpanzees with stable, efficient timing performances maintained by multilink chained schedules of food reinforcement. Reinforcements decreased with increasing dose, because of decreased frequencies of total operant timing responses and decreased accuracy of the timing performances which did occur. Higher doses exerted an effect for up to 3 days.