基因分裂和Rna剪接 - Melissa Moore P1
本视频由科普中国和生物医学大讲堂出品
Melissa Moore (U. Mass/HHMI) Part 1: Split Genes and Rna Splicing
In the first part of her talk, Dr. Moore explains that eukaryotic pre-mRna contains long stretches of non-protein coding sequences interspersed with protein coding regions. By recognizing specific sequences, cellular machinery splices out the non-coding introns leaving just the protein-coding exons in mRna. Although at first glance this may seem like a wasteful process, it is splicing that facilitates the evolution of new genes, and alternative splicing that allows a limited number of genes to produce a large number of proteins.
Dna连接反应
分子生物学中，连接是指通过形成磷酸二酯键将两个Dna片段连起来。连接反应是由一种叫连接酶的酶催化进行的。在细胞内，连接酶用于修复在Dna复制过程中的单链或双链的断裂。在实验室里，Dna连接酶用于分子克隆来连接插入片段和载体-它是宿主生物内复制目的片段的Dna载体分子。
本短片介绍了Dna连接。讲述了连接的基本原理以及准备一个常用的连接反应的逐步步骤，并讨论了连接反应中的关键因素，例如粘末端突出端的长度对反应温度的影响，如何调整Dna插入片段与载体的比例来防止自身连接。还将提及辅助连接的分子生物学工具如Klenow片段和虾的碱性磷酸酶SAP，并讲述连接的应用，例如邻位连接和为测序在片段上添加接头序列。
Dna凝胶电泳
Dna凝胶电泳是用来检测和分离Dna分子的一种技术。施加一个电场到由琼脂糖构成的凝胶基质上，凝胶中的带电粒子将根据其大小进行移动和分离。Dna骨架上带负电的磷酸集团会使得Dna片段移向阳极–它是带正电荷的电极。
本视频解释了Dna片段在琼脂糖凝胶上分离的原理，并提供了一个常用的逐步操作过程，包括如何准备琼脂糖凝胶，上样Dna样品，Dna电泳跑胶，观察Dna片段，以及实验完成后正确地处理凝胶和电泳缓冲液。
线虫Rna干扰的简介
Rna干扰是一种应用广泛，将外源双链Rna引入到生物体内从而导致目的基因的表达下调的技术。在线虫中应用Rna干扰技术极为简便高 效，因仅需用表达与目的基因互补双链Rna的大肠杆菌喂食线虫即可实现。
首先，本短片将介绍Rna干扰的概念和解释它如何导致目的基因表达下调。然后我们 将演示在线虫中应用Rna干扰的步骤。包括大肠杆菌和Rnai线虫平板的制备，线虫培养以及如何评估线虫中Rna干扰的效果。Rna干扰经常用于反向遗传 学筛选以揭示哪些基因对于执行特定的生物过程至关重要。另外，自动化反向遗传筛选能使表达下调更高效和并可用于大规模基因分析。最后，Rna干扰经常用于 研究线虫的发育生物学。自它发明以来，科学家利用Rna干扰技术在解释许多生物学现象上取得重大进展。
Controlling the Cell Cycle: Anaphase Onset - David O. Morgan
本视频由科普中国和生物医学大讲堂出品
David O. Morgan (UCSF) Part 3: Controlling the Cell Cycle: Anaphase Onset
In the anaphase stage of the cell cycle, the duplicated chromosomes are pulled apart by a machine called the mitotic spindle, resulting in the distribution of a complete set of chromosomes to each of the daughter cells. In the third part of this lecture, I describe the combination of biochemistry and microscopy in my laboratory that led to the discovery of a regulatory switch that triggers the abrupt and synchronous separation of the chromosomes at the onset of anaphase.
Photoreceptors and Image Processing Part 1A - Jeremy nathans
本视频由科普中国和生物医学大讲堂出品
Jeremy nathans (Johns Hopkins) Part 1A: Photoreceptors and Image Processing
In this set of lectures, Jeremy nathans explores the molecular mechanisms within the retina that mediate the first steps in vision. The first lecture focuses on the structure of the light sensing receptors, the intracellular signals that are triggered by light absorption, and the ways in which the retina extracts information from a complex scene. See more at http://www.ibioseminars.org
Photoreceptors and Image Processing Part 1B - Jeremy nathans
本视频由科普中国和生物医学大讲堂出品
Jeremy nathans (Johns Hopkins) Part 1B: Photoreceptors and Image Processing
In this set of lectures, Jeremy nathans explores the molecular mechanisms within the retina that mediate the first steps in vision. The first lecture focuses on the structure of the light sensing receptors, the intracellular signals that are triggered by light absorption, and the ways in which the retina extracts information from a complex scene. See more at http://www.ibioseminars.org
【视频教程】揭开exoRna的神秘面纱
Rna曾被认为只存在于细胞之中，在转录与翻译中起桥梁作用，但最新的研究发现，胞外囊泡外泌体中的Rna（exoRna）可以经胞外囊泡外泌体转运到其他细胞中并发挥调节作用。让我们一起来透过视频介绍，揭开exoRna的神秘面纱吧！
Unlocking the Mysteries of Extracellular Rna Communication
Once thought to exist only inside cells, Rna is now known to travel outside of cells and play a role in newly discovered mechanisms of cell-to-cell communication. Are these extracelluar Rnas (exRnas) involved in diseases like cancer, heart disease or neurological diseases like Alzheimer's? Could scientists learn how to use exRnas to diagnose diseases earlier or even to treat these diseases? The NIH Common Fund's Extracellular Rna Communication program aims to unlock the mysteries of exRnas, uncovering their roles in human health and disease.