What exactly is a plasmid? Virus? Biological weapons? The source of all evil?

Source: Back to Park ID: What exactly is the fanpu2019 plasmid? Virus? Biological weapons? The source of all evil? What are the mysteries and wonders of it? Write an article. The DNA of He Wenhui (Department of Biochemistry and Molecular Biology, Basic Medical College, Army Medical University) stores genetic information passed down from generation to generation, known as the "code of life".
the moment Watson and Crick discovered the double helix structure of DNA, the DNA "magic box" was opened and more and more different types of DNA molecules were decrypted.
study found that most DNA molecules are linear, such as human chromosome DNA, and can be as long as 2-3 meters if all DNA molecules in a single individual cell are expanded.
however, a class of DNA molecules present in bacteria is ring-shaped and shuttles through the vast DNA molecular universe.
Although it is only one thousandth of the size of a bacterial chromosome, it is magical - it is the magic of the plasmid.
virus-like rather than virus in the 1940s, anthrax spread across the Americas.
this is an acute zoonotic infection that initially spread to deer herds in Texas, killing large numbers of deer.
then found the same symptoms in the crowd: skin necrosis, ulcers, scorched bones, toxic blood and tissue edema... Eventually, the infected person died from acute infections of the lungs, intestines and meninges.
scientists are trying to tackle the epidemic by finding the source of the infection.
they found that the real culprit was a toxic substance in Bacillus anthrax.
, they believe the substance is a virus that infects host cells by rapid reproduction, causing disease in animals or humans.
it wasn't until 1950 that Joshua Lederberg, an American biologist, confirmed that the substance was not a virus and named it a plasmid in 1952.
plasmid is a ring-shaped DNA molecule ranging in size from 1-200kb, independent of bacterial chromosomes, and self-replicating.
bacteria have the most abundant plasmid content, and are also found in the spiral, line bacteria and yeast and other microorganisms.
the plasmids under the electromirror are covalent, closed, ring-like, small double-stranded hyperhelisic DNA molecules, shaped like "hemp flowers".
won the 1958 Nobel Prize in Physiology and Medicine for discovering plasmids and their function in bacterial genetic recombination.
, how do plasmids and viruses really differ, and why can scientists be confused for so long? First, plasmids, like viruses, can replicate themselves and reproduce quickly;
but the difference is clear: viruses are non-cellular forms made up of nucleic acid molecules (DNA or RNA) and proteins, invasive organic species that live in living organisms or even non-living organisms.
a virus in general has two or three components: RNA or DNA, proteins, lipids (some viruses do not).
and plasmids have only one component, DNA, and plasmids are part of cells.
although viruses and plasmids are not the same, but there are inextricably linked.
2017, a team of researchers at the University of New South Wales in Australia discovered a special plasmid in the body of an ancient bacteria that looks and behaves like a virus, but lacks the genes that indicate it is a virus.
can be said that this is a plasmid with viral properties.
the team speculated that the first virus esappearing may have evolved from such plasmids.
restless lymics, the lone-grain DNA is like a "hacker", able to get rid of the shackles of the host chromosome DNA replication regulatory system, independently "programmed" autonomous replication.
this is mainly due to the replication starting point on the plasmid DNA, which can open its own replication, as well as the corresponding regulatory genes, can control the frequency of replication.
this means that plasmids can alter the properties of host bacteria to be effective.
, the plasmids are metastasis.
under natural conditions, with the help of bacterial joints, the vast majority of wild plasmids can be transferred from one host cell to another, and can even enter different host bacteria that are close to kinship.
this process relies on the interaction of the expression product of the plasmid transfer-related gene- and other protein factors: the mob gene encodes the mobile-related protein, which, in the binding of the trameta-transfer protein, transfers the plasmid to the nic gap site of the new host cell, through which the plasmid can enter the new host cell through the gap.
however, a mountain is not two tigers, if the two plasmids have the same or similar replication substructure and regulatory mode, they can not be stable in the same host cell, this phenomenon is called plasmid incompatibility.
a lot of host bacteria in the black history of biological weapons, including E. coli, bacillus, and the bemolic spore (Anthrax).
the biological weapon developed on the basis of this species - anthrax bomb, is the first biological weapon developed after human understanding of pathogens.
1870, scientist Robert Koch isolated bacillus anthrax.
he found that the bacteria is extremely viable, easily cultured and stable, and that in vitro preservation for six months can still be sufficiently toxic and infectious.
however, Koch did not know the real cause of the deadly anthrax bacteria at the time.
it wasn't until the end of the 19th century that scientists discovered that the source of the anthrax force factor was pXO1 and pXO2.
plasmid pXO1 contains coded poison-producing genes, can produce toxic factors and a variety of toxins, plasmid pXO2 contains the genes necessary to encode bacterial membrane protein synthesis.
two toxic particles depend on each other, and the absence of any one plasmid will reduce the toxicity of Bacillus anthrax and produce a reduced strain.
During World War I, the German spy service put anthrax bacteria into a digestible test tube, wrapped in feed, to poison the neutral country's military horses, opened the curtain of modern bacterial warfare.
1928, Jacov Fishman, the father of Soviet biological weapons, discovered that the bacteria anthrax was high in strength and toughness, capable of explosion shock and dry treatment, so that bombs, shells and missiles could be loaded into weaponization, and that it could become the most biological warfare agent to pose a threat to humanity in the future.
1939, the infamous Japanese 731 troops in China's central Zhejiang, Fujian region a large number of cultivation of anthrax bacteria, and the use of living people to carry out bacterial tests and bacterial weapons effectiveness tests, resulting in a large number of deaths of our military and civilian.
the HA bomb (ha bomb) is an anthrax bomb, the appearance is similar to ordinary steel shell bomb, and the contained grenade bomb once exploded, anthrax bacteria will be infected through the wound killed targets, while causing decades of ground pollution.
1942, Britain requisitioned a small Scottish island, Greenyard, for an anthrax test, planning to drop anthrax bombs on German pastures to kill large numbers of livestock in order to cut off the supply of meat (hence the name "Operation Vegetarian" and create a nationwide outbreak of anthrax to remove Hitler's Nazi regime.
after world war ii, the United States has been secretly developing anthrax agents, such as the R-400 bomb.
However, the United States in 2001 suffered an unprecedented biological terrorist attack, known as the "American anthrax incident."
this incident has led to a global military rethinking, with countries beginning to implement the Biological Weapons Convention, which has shifted its research and development objectives from attack to defence.
research into Bacillus anthrax is strictly confined to the laboratory, including genetic modification of Bacillus anthrax and vaccine development.
at present, many countries, including our country, have developed a vaccine for Bacillus anthrax.
also demon also Buddha of course, plasmids are not the source of all evil.
1970s, scientists began to modify natural wild-type plasmids and apply them to genetic engineering, opening a new door to genetic engineering.
on the basis of retaining the advantages of natural plasmids, the artificially modified plasmids increased resistance markers, and people could screen different strains according to their needs. At the same time,
, the plasmid can also be designed to multi-clone site, the use of the relevant enzymes to open the plasmid molecules, access to the external DNA, the use of the characteristics of the plasmidself independent replication, the external DNA information to the host bacteria, in order to achieve the transformation of the characteristics. the discovery of
cancerous tumor-induced plasmids (tumor-induced plasmids) is epoch-making and leads humans into the era of genetically modified technology.
Ti plasmids are two-chain ring DNA molecules that can be independently replicated outside the aythum region of root cancer ouslobin cells.
1977, Belgian molecular biologists Marc Van Montagu and Jozef Schell confirmed that the Ti plasmid can integrate exogenous genes into the genome of host plants, producing excellent traits such as pest resistance, alkali resistance, herbicideresistance, extended shelf life of fruits and vegetables, and can also be used to produce drugs, antibodies, vaccines, etc.
applications related to Ti plasmids, the most striking is genetically modified foods.
in theory, humans can transform plants according to their own wishes through Ti plasmid conversion, and get the food they need.
in fact, humans have not stopped developing genetically modified foods since 1983, when scientists transferred the chloramphenicol resistance gene from bacteria into tobacco and obtained the world's first genetically modified plant.
more and more genetically modified foods come out of the laboratory and into people's lives, such as genetically modified soybeans, genetically modified potatoes and so on.
, for example, the scientists used DNA fragments containing drought-resistant genes to be in vitro amplification via PCR technology, and then smothered DNA fragments using various enzymes, and then stitched the products together at the Ti plasmid multi-clone site to obtain recombinant plasmids.
recombined plasmids are mediated by root cancer erthanus, infected with potato-injured tissue, and crops can obtain external drought-resistant genes, thus showing drought resistance.
controversy and prospects have never stopped since the moment they were born.
Although there is no evidence that genetically modified foods can cause harm to human health, scientific research is not deep enough on unexpected changes that can occur in the course of genetic manipulation and their long-term effects on health and the environment.
, many countries and regions, such as the United States, the United Kingdom, France, Australia, New Zealand, etc., have developed the corresponding laws and regulations, genetically modified food labeling and strict control.
at the same time, with the continuous development of cloning technology, the "magic" of plasmids has been more and more carried out, and the cloning, amplification, expression and preservation of the artificial plasmid DNA sequence has been widely used.
2017, the birth of the world's first pair of somatic cell cloned monkeys, "Huahua", marks China's international leading position in the study of animal models of non-human primate diseases.
this asexual cloning system based on plasmid vectors accelerates the development of new drugs for a variety of brain diseases (Alzheimer's disease, autism, etc.) as well as immunodeficiency, tumor, metabolic diseases. Although
plasmids are extremely small components in microbial cells, they play an important role and have great prospects in the development of biology.
it is like a key, opened the "magic box" of genes, both for human health and well-being, but also can trigger disasters and wars.
in the rapid development of biotechnology today, we can only make good use of this double-edged sword, in order to let the plasmids continue to benefit mankind, promote the sustainable development of society.
Source: Return to Park.