Name: how virus shapes help infection
Uploaded: 2019-03-11T09:21:23.000Z
Duration: 56 s
Channel: JoVE

K12 Standards

Louisiana Student Standards for Science

High School

Life Sciences

from-molecules-to-organisms-structures-and-processes

From Molecules To Organisms: Structures And Processes

HS-LS1-8

Viral Structure

虽然病毒
 
 有各种各样的形状和大小
 
 但是几种结构特征是一致的
 
 一个完全成熟的病毒颗粒
 
 一个病毒粒子
 
 含有一个核心
 
 全部的遗传内容或基因组
 
 含有DNA或RNA 周围有保护层
 
 衣壳由一个或多个不同的
 
 蛋白质亚基组成 也称为壳粒
 
 决定了他们的整体规模
 
 蛋白质外壳和核酸基因组
 
 共同形成核衣壳
 
 在这里 病毒没有包裹在脂质覆盖物中
 
 因此核衣壳和病毒粒子是相同的
 
 除了这些结构 病毒会有所差异
 
 但它们的主要功能是将遗传物质
 
 传递到宿主细胞中以进行病毒复制

Calil， Iara P. 和 Elizabeth PB Fontes。"植物对病毒的免疫力:聚焦抗病毒免疫受体。"植物学年鉴 119，第 5 期（2017 年 3 月）:711-23。[<a href="https://doi.org/10.1093/aob/mcw200" target="__blank">来源</a>]

病毒结构

病毒在形状和大小上都非常不同，但它们都有几个共同的结构特征。所有的病毒都有一个包含DNA或RNA基基因组的核心。核心被一种名为衣壳的蛋白质保护层所包围。衣壳由称为帽体的亚单位组成。衣壳和包含核心的基因组一起被称为核衣壳。

<h4>病毒的结构分类</h4>
 
许多标准被用来分类病毒，包括衣壳设计。大多数病毒有二十面体或螺旋状的衣壳，尽管有些病毒已经发展出更复杂的衣壳结构。二十面体是一个20边的准球形结构鼻病毒，引起普通感冒的病毒，是二十面体病毒。螺旋（即丝状或杆状）衣壳薄而线形，类似于圆柱核酸基因组位于螺旋衣壳的凹槽内。烟草花叶病毒是一种植物病原，是一种典型的螺旋病毒有些病毒的衣壳被衣壳外的脂质和蛋白质包裹。这种病毒包膜不是由病毒产生的，而是从宿主细胞获得的。这些包膜分子保护病毒并介导与宿主细胞的相互作用。
 
 病毒结构对感染和免疫至关重要
 
病毒衣壳不仅保护病毒的基因组，而且在与宿主细胞的相互作用中发挥着关键作用。例如，衣壳蛋白通过识别和结合宿主细胞上的特定细胞膜蛋白来实现感染。衣壳蛋白在揭开病毒基因组以使其在宿主体内复制方面也起着重要作用。
 
尽管衣壳和包膜的蛋白质和脂类能够引起感染，但这些分子是病毒所特有的，因此可以被宿主的免疫系统用来检测病毒的存在。这种免疫反应的激发子通常被称为微生物相关分子模式 (MAMPs)。在植物中，MAMPs会引发一连串的免疫反应，既能减轻当前的感染，又能使植物在将来被类似的病原体感染时为更强大的免疫反应做好准备。 MAMPs还诱导人的先天免疫反应，包括炎症和抗菌蛋白的产生。有些疫苗利用人体识别MAMPs的能力，以赋予特定病毒病原体免疫力。

病毒在形态和大小上极为多样，但它们都具有一些共同的结构特征。所有病毒都有一个核心，其中包含……

Education

教育

JoVE Core

Biology

生物学

Genetics

遗传学

Viruses

病毒

KEY TERMS AND CONCEPTS

关键术语与概念

how virus shapes help infection

Viruses have specific structures that help them infect host cells and trigger immune responses. Each virus has a core that contains either a DNA-based or RNA-based genome. That core is surrounded by a protective protein coat called the capsid. The capsid is made of smaller subunits called capsomeres. The capsid and the genome-containing core together are called the nucleocapsid.

Viruses are often grouped by capsid design. Most viruses have either icosahedral or helical capsids, but some have more complex structures. An icosahedral capsid is a 20-sided, quasi-spherical shape. Rhinovirus, which causes the common cold, is an example. A helical capsid is thin and linear, with a rod-like or filament-like shape. Its nucleic acid genome fits inside the grooves of the capsid. Tobacco mosaic virus, a plant pathogen, is a classic helical virus.

Some viruses also have an envelope outside the capsid. This envelope contains lipids and proteins. The virus does not make this envelope itself. It acquires it from the host cell. These envelope molecules help protect the virus and support interactions with host cells.

Viral structure is important for infection. Capsid proteins can recognize and bind to specific proteins on the host cell membrane. They also help uncoat the viral genome so replication can begin inside the host. The same proteins and lipids that help infection can also act as unique markers for the immune system. These markers are called microbe-associated molecular patterns, or MAMPs. In plants, MAMPs can trigger immune responses that reduce the current infection and prepare the plant for future attacks by a similar pathogen. In humans, MAMPs can also activate innate immune responses such as inflammation and the production of antimicrobial proteins. Some vaccines use the immune system's response to MAMPs to build protection against specific viral pathogens.

How Virus Shapes Help Infection

what are viruses?

How Viruses Infect Cells and Multiply

Viruses infect cells and make new copies by using a host cell’s own machinery. A virus is a tiny infectious particle with an RNA or DNA genome inside a protective protein coat. It cannot reproduce on its own, so it must enter a cell to make more viruses. After infection, the virus sheds its protein coat and uses the host cell to transcribe and translate its genetic material. The cell then assembles many new viral particles. In many cases, these new viruses rupture the host cell and kill it.

viral structure

Viruses have specific structures that help them infect host cells and trigger immune responses. Each virus has a core that contains either a DNA-based or RNA-based genome. That core is surrounded by a protective protein coat called the capsid. The capsid is made of smaller subunits called capsomeres. The capsid and the genome-containing core together are called the nucleocapsid. Viruses are often grouped by capsid design. Most viruses have either icosahedral or helical capsids, but some have...

lytic cycle of bacteriophages

How Phages Infect and Burst Bacteria

Bacteriophages, or phages, are viruses that infect bacteria. They have a distinctive head-tail shape. In the lytic cycle, a phage first attaches to the outside of a bacterial cell. Tail proteins bind to specific receptor proteins on the bacterium’s surface. After attachment, the phage tail injects its DNA genome into the bacterial cytoplasm. The phage then uses the bacterium’s cellular machinery to make proteins needed for replication and dispersal. When phage replication is complete, some of...

lysogenic cycle of bacteriophages

Prophage Integration in Bacteria

The lysogenic cycle shows how bacteriophages can infect bacteria without killing the host right away. In this cycle, the phage genome joins the bacterial genome. The integrated phage DNA is called a prophage, and the bacterium copies it each time it replicates. Some prophages can switch back into the lytic cycle. This change can happen after DNA damage or even without an obvious outside trigger. When the prophage is induced, the phage begins making new virus particles again. Prophages can...

retrovirus life cycles

How Retroviruses Replicate in Host Cells

Retroviruses replicate by copying their RNA genome into DNA inside a host cell. After entry, the viral enzyme reverse transcriptase makes a double-stranded DNA copy from the single-stranded RNA genome. The viral DNA is then carried into the nucleus and inserted into the host genome by integrase. Once integrated, the retroviral DNA is transcribed whenever the host genome is transcribed. This produces new viral RNA that can be copied and used again. The new RNA moves into the cytoplasm, where it...

viral recombination

How Viruses Swap Genes and Spread

Viral gene swapping can happen when more than one virus infects the same cell. After the viruses break open and expose their genomes for replication, matching regions can pair up and exchange sequences. This process is called recombination. Viruses with segmented genomes can also swap whole segments, which is called reassortment. These changes can help create new diseases. Some diseases can infect more than one species. Pigs can be infected by some human and bird viruses, along with the...

viral mutations

How Virus Mutations Drive Outbreaks

Virus mutations can change how quickly a virus evolves and spreads. A mutation is a change in the sequence of bases in DNA or RNA. Some mutations happen when the genome is copied. They are caused by errors made by polymerase enzymes, which replicate DNA or RNA. RNA viruses often change faster than DNA viruses because RNA polymerase does not proofread its work. That means RNA-based genomes, such as HIV, can gather mutations more quickly. Mutation and recombination give viruses the raw material...

key terms and concepts

Learn how virus structure, capsids, envelopes, and MAMPs help viruses infect cells and trigger immune responses in plants and humans.

How Virus Shapes Help Infection | JoVE K12

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Nucleic Acids and Nucleotides

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Nucleic Acid Structure

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Overview

Deoxyribonucleic acid, or DNA, is the genetic material responsible for passing traits from generation to generation in all organisms and most ...

DNA Packaging

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Eukaryotes have large genomes compared to prokaryotes. In order to fit their genomes into a cell, eukaryotes must pack their DNA tightly inside ...

RNA Structure

Overview
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RNA Stability

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pre-mRNA Processing

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Types of RNA

Overview
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DNA as a Genetic Template

What is Gene Expression?

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Transcription

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Translation

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Ribosomes

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tRNA Activation

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Termination of Translation

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Cell Diversity

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structure-and-organization-of-smooth-muscles

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...

Chromosome Replication

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Neurons: The Cell Body and the Dendrites

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Lampbrush Chromosomes

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Neurons: The Axon

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Nervous Tissue: Neuron Types

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Euchromatin

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Nervous Tissue: Glial Cells

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Heterochromatin

Lymphoid Cells and Tissues

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Lymphoid cells consist of immune system cells such as B and T ...

chromatin-position-affects-gene-expression

Chromatin Position Affects Gene Expression

Chromatin is the massive complex of DNA and proteins packaged inside the nucleus. The complexity of chromatin folding and how it is packaged inside the ...

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Organization of Genes

Chromosome Structure

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The centromere is a DNA ...

Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells. Emphasis is on the conceptual understanding that DNA sequences determine the amino acid sequence and thus protein structure. Students can produce scientific writing, or presentations, and/or physical models that communicate constructed explanations.

HS-LS1-1

Characteristics of Life

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Levels of Organization

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The Scientific Method

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Taxonomy

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Phylogeny

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Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms. Emphasis is on functions at the organism system level such as nutrient uptake, water delivery, or organism movement in response to neural stimuli. An example of an interacting system could be an artery depending on the proper function of elastic tissue and smooth muscle to regulate and deliver the proper amount of blood within the circulatory system.

HS-LS1-2

Overview of Metabolism

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Regulation of Metabolism

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Positive and Negative Feedback Loops

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Functions of Life

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What is Homeostasis?

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Negative and Positive Feedback

Homeostatic Imbalance

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pH Homeostasis

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homeostatic-imbalances-in-body-temperature

Homeostatic Imbalances in Body Temperature

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...

Regulation of Food Intake

The hypothalamus releases peptides influencing feeding behavior.
Two hypothalamic neuronal groups participate in this process.
Neuropeptide Y (NPY) and ...

Plan and conduct an investigation to provide evidence that feedback mechanisms maintain homeostasis in living organisms. Examples of investigations could include heart rate responses to exercise, stomate responses to moisture and temperature, root development in response to water levels, or cell response to hypertonic and hypotonic environments.

HS-LS1-3

What is the Cell Cycle?

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Interphase

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The Cell Cycle Control System

Positive Regulator Molecules

Inhibition of CDK Activity

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Mitogens and the Cell Cycle

Replicative Cell Senescence

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cells-coordinate-growth-and-proliferation

Cells Coordinate Growth and Proliferation

Mitosis and Cytokinesis

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Chromosome Duplication

Cohesins

Condensins

The Mitotic Spindle

Centrosome Duplication

Spindle Assembly

Attachment of Sister Chromatids

Use a model to illustrate the role of the cell cycle and differentiation in producing and maintaining complex organisms. Emphasis is on conceptual understanding that mitosis passes on genetically identical materials via replication, not on the details of each phase in mitosis.

HS-LS1-4

How Virus Shapes Help Infection

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