Developmental biology of T cell receptors

T cell receptors are the antigen-recognizing elements found on the effector cells of the immune system. Two isotypes have been discovered, TCR-gamma delta and TCR-alpha beta, which appear in that order during ontogeny. The maturation of prothymocytes that colonize the thymic rudiment at defined gestational stages occurs principally within the thymus, although some evidence for extrathymic maturation also exists. The maturation process includes the rearrangement and expression of the T cell receptor genes. Determination of these mechanisms, the lineages of the cells, and the subsequent thymic selection that results in self-tolerance is the central problem in developmental immunology and is important for the understanding of autoimmune diseases.     

Cell biology. Stem cell scorecard

As researchers continue to explore the potential uses of stem cells obtained from a variety of sources (see main text), governments around the world are grappling with whether to allow research on stem cells derived from human embryos. Governments are cautious yet increasingly open to the new research, which may eventually yield treatments for a variety of diseases from Parkinson's to diabetes.     

The cell biology of synaptic plasticity

Synaptic plasticity is the experience-dependent change in connectivity between neurons that is believed to underlie learning and memory. Here, we discuss the cellular and molecular processes that are altered when a neuron responds to external stimuli, and how these alterations lead to an increase or decrease in synaptic connectivity. Modification of synaptic components and changes in gene expression are necessary for many forms of plasticity. We focus on excitatory neurons in the mammalian hippocampus, one of the best-studied model systems of learning-related plasticity.     

Fluorescence digital imaging microscopy in cell biology

Developments in microscope, sensor, and image-processing technologies have led to integrated systems for the quantification of low-light-level emission signals from biological samples. Specificity is provided in the form of monoclonal antibodies and other ligands or enzyme substrates conjugated with efficient fluorophores. Fluorescent probes are also available for cellular macromolecular constituents and for free ions of biological interest such as H+ and Ca2+. The entire spectrum of photophysical phenomena can be exploited. Representative data are presented from studies of DNA conformation and architecture in polytene chromosomes and from studies of receptor-mediated endocytosis, calcium distribution, and the organization of the contractile apparatus in muscle cells.     

脂滴的生物物理学和细胞生物学研究

最早对脂滴的研究可以追溯到19 世纪,Richard Altmann 和E.B. Wilson 都描述了细胞 中的脂肪滴,并推测了它们的起源(Altmann, 1890;威尔逊,1896)。早期,脂滴的高衍射特性为其 鉴定提供了便利的光学条件。20 世纪初,由于它们被认为是大多数细胞的组成部分,这种细胞 器被称为脂质体。然而,在20 世纪60 年代末,人造脂质体被发明出来,并很快取代了这个名 字。从那时起,这种细胞器被有过许多名称,包括脂滴、脂体、脂体、脂滴和脂质体。在植物中, 它们通常被称为油体。随着这一领域的迅速发展,它似乎已经定名为“脂滴”。几十年来,除了 形态学研究,脂滴的其他方面几乎没有受到关注。1991 年,脂肪细胞中与脂滴相关的磷酸蛋白 perilipin 的发现,引起人们对这种细胞器的新关注。从那时起,关于脂滴的论文数量急剧增加, 关于脂滴的功能也逐渐被重视起来。     

《细胞生物学》实验的教学改革初探

为了使实验教学更加符合理论教学的实际需要、充分配合课堂教学,对《细胞生物学》实验的教学实验内容进行调整优化,加大了实验教学学时比重。通过对实验组合和结构进行优化,适时安排问题与讨论时间,培养了学生的科学兴趣、激发了学生的学习欲望,充分调动了学生的学习积极性。在实验过程中积极运用现代化电教手段辅助教学,理论与实验操作技巧并重。同时,积极申请经费来源,努力提高自身优势,向开放性实验室的建设迈进。     

Emerging challenges in regulatory T cell function and biology

Much progress has been made in understanding how the immune system is regulated, with a great deal of recent interest in naturally occurring CD4+ regulatory T cells that actively engage in the maintenance of immunological self-tolerance and immune homeostasis. The challenge ahead for immunologists is the further elucidation of the molecular and cellular processes that govern the development and function of these cells. From this, exciting possibilities are emerging for the manipulation of regulatory T cell pathways in treating immunological diseases and suppressing or augmenting physiological immune responses.