authorization reprint, original author: planet Institute, writing: Magnolia by word, editor: Li Zhang Ziwei, Figure Code: Renbing Xu, revision: Hasty Li Zhang Ziwei.
Some worlds
It is invisible to human eyes
But this doesn’t mean they don’t exist
January 24, 2020
Photos of new coronavirus virus species first made public
National people shrouded in the shadow of the epidemic
I can finally see it with my naked eyes
The true meaning of this “culprit”
(SEM picture of new coronavirus, picture source @ 国 病 病 生物 生物 库) ▼
And for hundreds of years
When a scientist relies on a microscope
Magnify the world a hundred times, ten thousand times
Even hundreds of thousands of times
A field of human experience
The truth about pain and suffering
It becomes more and more visible
In this special
You will see
20 photomicrographs
And the story these pictures tell us
I. Source of Disease
They lurk in every corner, ready to attack.
Virus is one of them.
①H1N1 subtype of influenza A virus (Natural host: pig)
In 1918, the virus caused the “Spanish flu” globally, killing more than 50 million people; more than 90 years later, its new variant again triggered the 2009 global flu, with more than 1.6 million people diagnosed and nearly 2 deaths People, were listed by the World Health Organization (WHO) as public health emergencies of international concern (PHEIC) .
Specific drugs and vaccines are available. However, this zoonotic influenza virus is highly susceptible to genetic recombination in pigs, creating new variants.
The light circle is H1N1 influenza A virus; imaging by transmission electron microscopy, and later staining. Image source @ NIAID ▼
② Zika virus (Zika virus) (natural host: macaque)
In 1947, it was found in macaques in the Zika jungle in Uganda. In 1952, humans were first confirmed to be infected with mosquitoes. Can be used as an intermediate host. The Zika outbreak from Brazil in 2015-2016 caused about 180,000 infections worldwide and was listed by the WHO as a PHEIC event. Despite its low mortality rate, infections in pregnant women can cause congenital malformations such as microcephaly in infants, and there is no cure.
No specific medicines or vaccines yet.
The red circle is Zika virus. Transmission electron microscope negative staining imaging, image source @ NIAID ▼
③Marburg virus (Marburg virus) (Natural host: Egyptian fruit bat) < / span>
In 1967, the virus was first detected in Marburg and Frankfurt, Germany, and now Serbia. It has caused a total of 10 outbreaks so far, with an average case fatality rate of about 50%. African green monkeys and pigs may serve as intermediate hosts. In the largest outbreak in Angola in 2005, only 45 of the 374 infected cases survived and died.The rate is as high as 88%.
No specific medicines or vaccines yet.
Marburg virus (blue filament) attaches to infected VERO E6 cells (yellow); scanning electron microscope imaging, later staining. Image source @ NIAID ▼
④Ebola virus (Ebola virus) Manta)
This is the second filamentous virus discovered by humans after Marburg virus. Founded in South Sudan and the Democratic Republic of the Congo for the first time in 1976, it has caused 38 outbreaks worldwide, with an average case fatality rate of 50% and a maximum of 90%. Chimpanzees, gorillas, monkeys, antelopes, porcupines, etc. can be used as intermediate hosts. Among them, the Ebola outbreak in West Africa was the worst in 2014-2016, with more than 10,000 deaths and being listed by the WHO as a PHEIC incident. The epidemic broke out again in August 2018 in the Democratic Republic of the Congo and was included in the PHEIC incident again.
No specific medicine is available, but the first Ebola vaccine in November 2019 has been approved in the European Union and the United States, and has entered the WHO pre-certification process.
Ebola virus (blue filament) attaches to infected VERO E6 cells (green); scanning electron microscope imaging, later staining. Image source @ NIAID ▼
⑤Nipa virus (Nipah virus) Genus)
It was first confirmed in Malaysia in 1999. Since then, there have been many outbreaks in Bangladesh, Singapore, India and other countries. In the 2008 outbreak in Kerala, India, more than 2,000 people were isolated, and only 2 of the 18 infected people survived.
No specific medicines or vaccines yet.
The blue circle is Nipah virus, the purple is infected VERO E6 cells; transmission electron microscope imaging, later staining. Image source @ NIAID ▼
⑥SARS coronavirus (Natural host: Asteraceae, Asteraceae) / span>
It was first discovered in Guangdong, China in November 2002. The flower-faced raccoon (fruit beaver) , tadpoles, tadpoles, etc. can serve as intermediate hosts. The condition it causes is called severe acute respiratory syndrome (SARS) . To 2On July 31, 003, about 8,000 cases of infection were confirmed in 26 countries around the world, with a mortality rate of about 10%. Among them, 5327 cases were confirmed in mainland China and 349 people died. Since the SARS epidemic, the WHO has established an emergency committee to begin the evaluation and announcement of the PHEIC incident.
No specific medicines or vaccines yet.
The orange circle is the SARS virus; imaged with a transmission electron microscope, stained later. Image source @ NIAID ▼
⑦MERS Coronavirus (Natural host: unimodal camel or bat, inconclusive)
In 2012, it was first confirmed in Saudi Arabia that the disease it caused was called the Middle East Respiratory Syndrome (MERS) . By 2015, there were about 1,300 confirmed cases of infection in 27 countries around the world, and the mortality rate was about 35%. Of these, 1084 confirmed cases occurred in the 2012 outbreak.
No specific medicines or vaccines yet.
The yellow circle is the MERS virus, and the outer “coronal” envelope protein can be seen; transmission electron microscope imaging, later staining. Image source @ NIAID ▼
Second, infection
The invasion has begun quietly where you can’t see it.
The two round structures on the right side of the picture below are the glands of the tick. One of the tick’s acinars has been infected by Langat virus (Langat virus) infection, if it bites a human, it may cause Langat encephalitis .
Green fluorescently labeled acinar has been infected; confocal microscopy imaging. Image source @ NIAID ▼
⑨This is a cell infected by Langat virus (Langat virus) . The virus-encoded protein NS51 is a secondary to infected cells. Peptidase interactions can prevent an infected cell from producing an antiviral response. Fortunately, this arbovirus cannot be transmitted from person to person, and effective vaccines have been developed.
Red is the viral protein NS51, and green is the prolylase. Image source @ NIAID ▼
The picture below is a cell infected with Rotavirus (Rotavirus) , the virus is in the cytoplasm The formation of a large number of “virus factories” , where the reproduction and assembly of the offspring are completed. These viruses can cause acute gastroenteritis. Although a relatively effective vaccine is available, about 200,000 children under the age of 5 die each year, mainly in low-income countries.
Blue is the nucleus. Image source @ NIAID ▼
⑪ Bacteria will also be infected by viruses. A large number of phage viruses are attaching to the surface of a bacterium in the picture below. Generally, their protein shells do not enter the host cell, but instead inject DNA into the host. In cells, the substance of the host cell is used for replication and assembly. Some bacteriophages will eventually lyse host cells and release large numbers of progeny.
The circle with a large area is a bacterial cell, and a large number of circular structures on the outside are phage viruses adsorbed thereon; transmission electron microscope imaging. Image source @Wikimedia Commons ▼
⑫ Some pathogens are contagious even without DNA or RNA. Prion (Prion) is an infectious factor composed of only proteins, which can cause misfolding of normal proteins. In the image below, this misfolded protein is infecting adjacent cells along the slender synapses of nerve cells. Infected nerve cells will gradually degenerate, leading to neurodegenerative diseases (mainly infectious spongiform encephalopathy, such as Mad Cow disease, etc.) .
Red is the infected protein. Image source @ NIAID ▼
Three, struggle
The immune system is our last natural line of defense.
⑬ But in the face of the invasion of pathogens, we are definitely not waiting. The figure below is a normal human blood cell. In addition to red blood cells and discoid platelets, there are also many white blood cells. They are important immune cells in the human body, mainly including 5 types of neutrophils, eosinophils, basophils, lymphocytes, and monocytes.
Scanning electron microscope imaging. Image source @Wikimedia Commons ▼
⑭ Among them, neutrophils (also known as neutrophils) The type with the highest ratio is also an important line of defense for the human body against pathogenic microorganisms such as bacteria and fungi. The picture below is a neutrophil that is engulfing Bacillus anthracis.
Orange strips are Bacillus anthracis and yellow are neutrophils; scanning electron microscope imaging, later staining. Image source @Wikimedia Commons ▼
The picture below is a neutrophil that is phagocytosing methicillin-resistant Staphylococcus aureus strong>, if lucky, these swallowed bacteria will be dissolved and digested by lysozyme and so on in neutrophils. After killing the bacteria, the neutrophils will also die and become pus, which is called “purulent”.
The yellow sphere is MRSA, and the purple is human neutralCells; scanning electron microscope imaging, late staining. Image source @ NIAID ▼
⑯ When monocytes in leukocytes leave blood vessels and enter tissues, they can differentiate into macrophages , which can engulf free pathogens, dead cells, and cell debris. In the picture below, a mouse macrophage is stretching its slender, fake enough to engulf particles that may be pathogens.
Image source @Wikimedia Commons ▼
⑰After phagocytosis, macrophages will use lysosomes to digest these pathogens and integrate pathogen-specific antigens into the cell membrane. This “antigen presentation” effect will stimulate the immune system to target The pathogen produces antibodies. In the figure below, the phagocytized mouse macrophages exposed the phagocytosed T. francis (Francisella tularensis) .
Yellow is macrophages, blue spherical is T. francis; scanning electron microscope imaging, later staining. Image source @ NIAID ▼
⑱But not every time these immune cells are so lucky. The picture below is the methicillin-resistant Staphylococcus aureus that successfully killed and escaped human neutrophils. (MRSA) . This “superbug” was first discovered in the United Kingdom in 1961, and is resistant to a variety of penicillin antibiotics, including methicillin, which can cause radon and even necrotizing fasciitis.
Yellow spheres are MRSA, red are neutrophils; scanning electron microscope imaging, later staining. Image source @ NIAID ▼
⑲ In addition, Immune cells themselves may also be infected by pathogens and lose their immunity. The picture below shows human T lymphocytes infected with HIV. The HIV virus that enters the host cell integrates its genetic material into the host cell’s DNA and replicates with the host cell, which may trigger AIDS and cause a deficiency in immune function. Eventually, the host will die from infection, cancer and other diseases. As of the end of 2018, approximately 37.9 million people worldwide were infected with the HIV virus.
Blue is human T lymphocytes, and yellow spheres attached to the surface are HIV viruses; scanning electron microscope imaging, later staining. Picture comesSource @ NIAID ▼
⑳ However, the stronger the immune response, the better. There is also a special type of lymphocyte in white blood cells-regulatory T cells (Regulatory T cell) to regulate and control the autoimmune response. Without it, an excessive immune response will make the immune system “recognize friends as enemies”, attack its own normal cells, and eventually cause “self-destruction.”
Regulatory T cells (red) are interacting with antigen-presenting cells (blue), inducing them to produce inhibitory receptors, suppressing immune response activation; scanning Electron microscope imaging, post-staining. Image source @ NIAID ▼
This “invisible” world
Follow the long history of life evolution like shadow
And humans see them through a microscope for the first time
It’s just over 300 years ago
How complicated it is
It is also far beyond our imagination
Even in this era of unprecedentedly developed human civilization
Globally due to various infectious diseases
Maternal and neonatal diseases
and deaths from malnutrition
Still close to 10 million people
The sudden outbreak is still happening unprepared
But looking at human history
No more vicious germs, no more terrible epidemic
It didn’t make mankind to perish
Because there is always such a group of people
No matter how difficult the situation is
Still persevering and exploring
Unlock a game for us
The truth behind panic, pain, and death
While standing on their shoulders
Only then can we see the world that we knew nothing about
We are confident and still looking forward to tomorrow
WeChat public account “Planet Institute” (ID: xingqiuyanjiusuo) Authorized reprint, written by: Mulan minus, editor: Li Zhang Ziwei, editor: Ren Bingxu, proofreader: Dong Dong, Li Zhang Ziwei. Original author: Planet Institute, a group of National Geographic-controlled, focused on the exploration of the ultimate world.