对头足纲动物视觉感知机制的探索 - Roger Hanlon P2
本视频由科普中国和生物医学大讲堂出品
Roger Hanlon (MBL) Part 2: Exploring Mechanisms of Visual Perception
Hanlon introduces the amazing adaptive coloration of cephalopods. He uses video and still photography to showcase their ability to rapidly change color, pattern and skin texture with fine control and a diversity of appearances, to produce camouflage or to send signals. He argues that all camouflage patterns in nature can be grouped into three types. In part 2, Hanlon shows us results from his lab that make a convincing case that the rapid adaptive coloration of cephalopods is controlled by their visual system; quite impressive for a color-blind animal! Part 3 focuses on the unique skin of cephalopods including the system of pigments and reflectors that allows it to quickly change to any hue and contrast, and the papillae musculature that allows the skin to deform and create multiple 3D textures.
头足纲动物的可变化的皮肤细胞 - Roger Hanlon P3
本视频由科普中国和生物医学大讲堂出品
Roger Hanlon (MBL) Part 3: Changeable Skin
Hanlon introduces the amazing adaptive coloration of cephalopods. He uses video and still photography to showcase their ability to rapidly change color, pattern and skin texture with fine control and a diversity of appearances, to produce camouflage or to send signals. He argues that all camouflage patterns in nature can be grouped into three types. In part 2, Hanlon shows us results from his lab that make a convincing case that the rapid adaptive coloration of cephalopods is controlled by their visual system; quite impressive for a color-blind animal! Part 3 focuses on the unique skin of cephalopods including the system of pigments and reflectors that allows it to quickly change to any hue and contrast, and the papillae musculature that allows the skin to deform and create multiple 3D textures.
病毒结构的一般原则 - Stephen Harrison P1
本视频由科普中国和生物医学大讲堂出品
Stephen Harrison (Harvard) Part 1: Virus structures: General principles
Harrison begins his talk by asking why most non-enveloped viruses and some enveloped viruses are symmetrical in shape. He proceeds to show us lovely images of the structures obtained by x-ray crystallography of numerous viral coat proteins. Deciphering these structures allowed scientists to understand that viral coat proteins form multimers, such as dimers and pentamers, which in turn interact with a scaffold that ensures that the coat proteins are correctly placed. This arrangement results in symmetrically shaped viruses.
In Part 1, Harrison also explains that enveloped viruses infect cells by inducing the fusion of the viral and host cell membranes. He delves deeper into the molecular mechanism of membrane fusion driven by the hemagglutinin or HA protein of the influenza virus in Part 2 of his talk.
Non-enveloped viruses, on the other hand, must enter cells by a mechanism other than membrane fusion. This is the focus of Part 3. Using rotavirus as a model, Harrison and his colleagues have used a combination of Xray crystallography and electron cryomicroscopy to decipher how the spike protein on the viral surface changes its conformation and perforates the cell membrane allowing the virus to enter the cell.
病毒的膜融合 - Stephen Harrison P2
本视频由科普中国和生物医学大讲堂出品
Stephen Harrison (Harvard) Part 2: Viral membrane fusion
Harrison begins his talk by asking why most non-enveloped viruses and some enveloped viruses are symmetrical in shape. He proceeds to show us lovely images of the structures obtained by x-ray crystallography of numerous viral coat proteins. Deciphering these structures allowed scientists to understand that viral coat proteins form multimers, such as dimers and pentamers, which in turn interact with a scaffold that ensures that the coat proteins are correctly placed. This arrangement results in symmetrically shaped viruses.
In Part 1, Harrison also explains that enveloped viruses infect cells by inducing the fusion of the viral and host cell membranes. He delves deeper into the molecular mechanism of membrane fusion driven by the hemagglutinin or HA protein of the influenza virus in Part 2 of his talk.
Non-enveloped viruses, on the other hand, must enter cells by a mechanism other than membrane fusion. This is the focus of Part 3. Using rotavirus as a model, Harrison and his colleagues have used a combination of Xray crystallography and electron cryomicroscopy to decipher how the spike protein on the viral surface changes its conformation and perforates the cell membrane allowing the virus to enter the cell.
非包膜病毒如何侵入细胞 - Stephen Harrison P3
本视频由科普中国和生物医学大讲堂出品
Stephen Harrison (Harvard) Part 3: Non-enveloped virus entry
Harrison begins his talk by asking why most non-enveloped viruses and some enveloped viruses are symmetrical in shape. He proceeds to show us lovely images of the structures obtained by x-ray crystallography of numerous viral coat proteins. Deciphering these structures allowed scientists to understand that viral coat proteins form multimers, such as dimers and pentamers, which in turn interact with a scaffold that ensures that the coat proteins are correctly placed. This arrangement results in symmetrically shaped viruses.
In Part 1, Harrison also explains that enveloped viruses infect cells by inducing the fusion of the viral and host cell membranes. He delves deeper into the molecular mechanism of membrane fusion driven by the hemagglutinin or HA protein of the influenza virus in Part 2 of his talk.
Non-enveloped viruses, on the other hand, must enter cells by a mechanism other than membrane fusion. This is the focus of Part 3. Using rotavirus as a model, Harrison and his colleagues have used a combination of Xray crystallography and electron cryomicroscopy to decipher how the spike protein on the viral surface changes its conformation and perforates the cell membrane allowing the virus to enter the cell.
病毒与宿主细胞表面结合的方式 - Ari Helenius P1
本视频由科普中国和生物医学大讲堂出品
Ari Helenius (ETH Zurich) Part 1: Virus entry
Viruses are extremely simple and small yet they are responsible for many of the worlds diseases. A virus particle consists of only a genome, a protein coat or capsid, and sometimes a surrounding lipid envelope. To replicate, a virus must successfully enter a host cell, uncoat its genome, and appropriate the host cell machinery to replicate its genome and produce viral proteins. Part 1 of this lecture will discuss ways in which viruses bind to the surface of host cells. Simian Virus 40 which binds to specific cell surface glycolipids, and Human Papilloma Virus-16 which binds to sites on filoipodia, are examples of different binding mechanisms. Attachment of viruses to the plasma membrane activates cell signaling resulting in endocytosis of the viral particles. This lecture is appropriate for upper level undergraduate and graduate classes studying virology or endocytosis.
牛痘病毒如何进入细胞 - Ari Helenius P3
本视频由科普中国和生物医学大讲堂出品
Ari Helenius (ETH Zurich) Part 3: Open Sesame: Cell Entry and Vaccinia Virus
Part 3 focuses on a single virus, the Vaccinia virus, as a model for cell binding, signaling and endocytosis. Fluorescently labeled Vaccinia viruses bind to and surf along host cell filopodia. Helenius lab members noticed that when Vaccinia, unlike other viruses, reached the surface of the cell body it caused the plasma membrane to form blebs. Further experiments showed that the virus tricks the cell into thinking it is apoptotic debris. This induces blebbing and subsequent uptake of the virus by macropinocytosis. Additionally, automated high throughput siRNA screening was used to screen a large number of infected cells for host genes required for Vaccinia virus uptake. Analysis of the genes identified allowed host factors and processes critical to viral infection to be identified. Expansion of this technique may provide a new source of information on pathogen-host interactions.
控制声乐学习行为的大脑通路 - Erich Jarvis P1
本视频由科普中国和生物医学大讲堂出品
Erich Jarvis (Duke/HHMI) Part 1: Convergent behavior and brain pathways
In Part 1, Jarvis explains that vocal learning is the ability to hear a sound and repeat it. Only 5 groups of mammals (including humans) and 3 groups of birds (parrots, hummingbirds and songbirds) are capable of vocal learning. Jarvis and his lab members imaged changes in gene expression in bird's brains after singing. They found that hummingbirds, songbirds and parrots each have pathways in specific areas of the brain that are not found in non-vocal learning birds. Interestingly, analogous networks exist in the human brain but not in non-vocal learning monkeys.
In Part 2, Jarvis proposes a mechanism by which vocal learning may have evolved. He suggests that the brain areas that control vocal learning are the result of a duplication of a pre-existing neural circuit that controls motor movement. A similar duplication event may have occurred during the evolution of humans with the result that both humans and Snowball, a cockatoo, can sing and dance to a beat!
In Jarvis' third talk, he demonstrates that the brain pathways necessary for vocal learning are associated with the expression of particular axonal guidance genes. He also proposes that the evolutionary events responsible for the development of vocal learning may be a general mechanism for the development of other complex behavioral traits.
声乐学习起源的肌动模型 - Erich Jarvis P2
本视频由科普中国和生物医学大讲堂出品
Erich Jarvis (Duke/HHMI) Part 2: Motor theory of vocal learning origin
In Part 1, Jarvis explains that vocal learning is the ability to hear a sound and repeat it. Only 5 groups of mammals (including humans) and 3 groups of birds (parrots, hummingbirds and songbirds) are capable of vocal learning. Jarvis and his lab members imaged changes in gene expression in bird's brains after singing. They found that hummingbirds, songbirds and parrots each have pathways in specific areas of the brain that are not found in non-vocal learning birds. Interestingly, analogous networks exist in the human brain but not in non-vocal learning monkeys.
In Part 2, Jarvis proposes a mechanism by which vocal learning may have evolved. He suggests that the brain areas that control vocal learning are the result of a duplication of a pre-existing neural circuit that controls motor movement. A similar duplication event may have occurred during the evolution of humans with the result that both humans and Snowball, a cockatoo, can sing and dance to a beat!
In Jarvis' third talk, he demonstrates that the brain pathways necessary for vocal learning are associated with the expression of particular axonal guidance genes. He also proposes that the evolutionary events responsible for the development of vocal learning may be a general mechanism for the development of other complex behavioral traits.
声乐学习与特定的轴突导向基因的表达有关 - Erich Jarvis P3
本视频由科普中国和生物医学大讲堂出品
Erich Jarvis (Duke/HHMI) Part 3: Genes specialized in vocal learning circuits
In Part 1, Jarvis explains that vocal learning is the ability to hear a sound and repeat it. Only 5 groups of mammals (including humans) and 3 groups of birds (parrots, hummingbirds and songbirds) are capable of vocal learning. Jarvis and his lab members imaged changes in gene expression in bird's brains after singing. They found that hummingbirds, songbirds and parrots each have pathways in specific areas of the brain that are not found in non-vocal learning birds. Interestingly, analogous networks exist in the human brain but not in non-vocal learning monkeys.
In Part 2, Jarvis proposes a mechanism by which vocal learning may have evolved. He suggests that the brain areas that control vocal learning are the result of a duplication of a pre-existing neural circuit that controls motor movement. A similar duplication event may have occurred during the evolution of humans with the result that both humans and Snowball, a cockatoo, can sing and dance to a beat!
In Jarvis' third talk, he demonstrates that the brain pathways necessary for vocal learning are associated with the expression of particular axonal guidance genes. He also proposes that the evolutionary events responsible for the development of vocal learning may be a general mechanism for the development of other complex behavioral traits.