Inside the Coronavirus
What scientists know about the inner workings of the pathogen that has infected the world
对于这一切仍然是未解之谜about the novel coronavirus and the COVID-19 disease it causes, scientists have generated an incredible amount of fine-grained knowledge in a surprisingly short time.
In the graphics that follow,亚博电子竞技presents detailed explanations, current as of mid-June, into how SARS-CoV-2 sneaks inside human cells, makes copies of itself and bursts out to infiltrate many more cells, widening infection. We show how the immune system would normally attempt to neutralize virus particles and how CoV-2 can block that effort. We explain some of the virus's surprising abilities, such as its capacity to proofread new virus copies as they are being made to prevent mutations that could destroy them. And we show how drugs and vaccines might still be able to overcome the intruders. As virologists learn more, we will update these graphics on our Web site (www.scientificamerican.com）。
A SARS-CoV-2 virus particle wafting into a person's nose or mouth is about 100 nanometers in diameter--visible only with an electron microscope. It is a near sphere of protein (cross section shown) inside a fatty membrane that protects a twisting strand of RNA--a molecule that holds the virus's genetic code. Proteins called "S" form spikes that extend from the surface and grab onto a human cell, hundreds of times larger, so the particle, or virion, can slip inside; the crown, or corona, appearance gives the virus its name. Structural proteins--N, M and E--move inside the cell, where they help new virions form.
- 2. RNA（red）：这种RNA的扭曲链是蓝图病毒利用自我复制你的内心。
- 4. N蛋白（Blue）：这种蛋白质有助于保持病毒RNA稳定。
- 6. E蛋白（Yellow）：这种蛋白质有助于新的病毒颗粒的形式。
- 7. M蛋白（Purple）：这种蛋白质有助于新的病毒颗粒的形式。
A SARS-CoV-2 particle enters a person's nose or mouth and floats in the airway until it brushes against a lung cell that has an ACE2 receptor on the surface. The virus binds to that cell, slips inside and uses the cell's machinery to help make copies of itself. They break out, leaving the cell for dead, and penetrate other cells.
Additional vesicles (that come from the endoplasmic reticulum and Golgi complex) assemble spike, M and E proteins.
Infected cells send out alarms to the immune system to try to neutralize or destroy the pathogens, but the viruses can prevent or intercept the signals, buying time to replicate widely before a person shows symptoms. When infection begins, the innate immune system tries to immediately protect lung cells. The adaptive immune system gears up for a greater response.
Tactic 1:The virus spike may camouflage itself with sugar molecules. They flex and swing, potentially blocking antibodies from attaching to the virus, neutralizing it.
Commercial and university labs are investigating well over 100 drugs to fight COVID-19, the disease the SARS-CoV-2 virus causes. Most drugs would not destroy the virus directly but would interfere with it enough to allow the body's immune system to clear the infection. Antiviral drugs generally stop a virus from attaching to a lung cell, prevent a virus from reproducing if it does invade a cell, or dampen an overreaction by the immune system, which can cause severe symptoms in infected people. Vaccines prepare the immune system to quickly and effectively fight a future infection.
在SARS-COV-2基因组是RNA的链是大约29,900个碱基长 - 为附近RNA病毒的极限。流感有大约13500个碱基，并引起普通感冒的鼻病毒有大约8,000。（A基是一对是RNA和DNA的积木化合物）。因为基因组是复制会削弱病毒期间可能发生如此之大，许多突变，但SARS-CoV的-2能够校对和正确拷贝。这种质量控制是在人细胞和DNA病毒共同但在RNA病毒极不寻常的。长基因组也有辅助基因，尚不完全清楚，其中一些可能会帮助它抵挡我们的免疫系统。