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.
控制老化的基因 - Cynthia Kenyon P1
本视频由科普中国和生物医学大讲堂出品
Cynthia Kenyon (UCSF) Part 1: Genes that Control Aging
Once it was thought that aging was just a random and haphazard process. Instead, the rate of aging turns out to be subject to regulation by transcription factors that respond to hormones and other signals. In the nematode C. elegans, in which many key discoveries about aging were first made, the aging process is subject to regulation by food intake, sensory perception, and signals from the reproductive system. Changing genes and cells that affect aging can lengthen lifespan by six fold, and can also delay age-related disease, such as the growth of tumors.
来自生殖系统的信号显示衰老的规律 - Cynthia Kenyon P2
本视频由科普中国和生物医学大讲堂出品
Cynthia Kenyon (UCSF) Part 2: The Regulation of Aging by Signals from the Reproductive System
Once it was thought that aging was just a random and haphazard process. Instead, the rate of aging turns out to be subject to regulation by transcription factors that respond to hormones and other signals. In the nematode C. elegans, in which many key discoveries about aging were first made, the aging process is subject to regulation by food intake, sensory perception, and signals from the reproductive system. Changing genes and cells that affect aging can lengthen lifespan by six fold, and can also delay age-related disease, such as the growth of tumors.
枯草芽孢杆菌中芽孢的形成 - Richard Losick P1
本视频由科普中国和生物医学大讲堂出品
Richard Losick (Harvard) Part 1: Spore Formation in Bacillus Subtilis
How do simple cells differentiate, assemble into communities, and cope with change? Losick's seminar addresses these questions in the spore-forming bacterium Bacillus subtilis. Part I is an overview of how B. subtilis makes a spore.
多细胞生物的新研究 - Richard Losick P2
本视频由科普中国和生物医学大讲堂出品
Richard Losick (Harvard) Part 2: New Research on Multicellularity
Part II presents research on the capacity of B. subtilis cells to form architecturally complex communities.
枯草芽孢杆菌的不确定性和细胞结局 - Richard Losick P3
本视频由科普中国和生物医学大讲堂出品
Richard Losick (Harvard) Part 3: Stochasticity and Cell Fate
Part III presents research showing that B. subtilis uses a bet hedging strategy for coping with uncertainty.