Viruses mutate rapidly to avoid the attack of biological immune system, while plants use so-called RNA interference (RNAi) to combat virus mutation. The latest research by American scientists shows that fruit flies will use the same mechanism to fight viruses, which is the first time that this phenomenon has been found in animals.
In addition, British scientists found in a related study that in order to cope with the rapid mutation of the virus, the genes that perform RNA interference tasks in Drosophila are also changing rapidly. These findings may provide clues for developing new antiviral drugs and treatments.
For most living things, RNA (ribonucleic acid) is the intermediate link for biological cells to synthesize protein from DNA (deoxyribonucleic acid). Many viruses are RNA themselves. They sneak into the host genome and trick cells into making virus proteins. Scientists have found that cells can remove excess RNA through RNA interference, but animals have not been observed to resist viruses in this way before.
Microbiologists at the University of California, Riverside, recently reported in the journal Science that they infected fruit flies with two viruses, and the fruit flies lacking three main RNA interference genes were the experimental objects. Results The mortality rate of these mutant Drosophila melanogaster was much faster than that of common Drosophila melanogaster, which indicated that RNA interference gene could help Drosophila to resist virus invasion.
Scientists at the University of Edinburgh in the United Kingdom compared more than 8,000 genes of three kinds of fruit flies, and found that among different kinds of fruit flies, the three main RNA interference genes had the greatest difference, indicating that these genes evolved faster than other genes. According to calculation, the evolution speed of RNA interference genes exceeds 97% of Drosophila genome. Scientists say this is in response to the rapid mutation of the virus. This paper is published in the new issue of Contemporary Biology.
Since humans also have similar RNA interference genes, the above two new studies mean that humans may also use the same method to resist viruses. This virus will use some protein to block the effect of RNA interference genes, and inhibiting these protein may help to prevent and treat viral infection.
(Science and Technology Daily)
There are three mechanisms of plant disease resistance: one is the mechanical characteristics of the shape, structure and function of plant external tissues to prevent and reduce the invasion of pathogenic bacteria; Second, the tissue characteristics and physiological and biochemical reactions of plant cells inhibit the spread of pathogenic bacteria after invasion; Thirdly, after being infected by pathogens, some plants can actively produce a defensive response to pathogens, which prevents the spread of pathogens. According to whether plants specialize in pathogenic strains or physiological races, they can be divided into horizontal resistance and vertical resistance.
The mechanism of horizontal resistance mainly includes physiological and biochemical resistance to contact, invasion and expansion except allergic necrosis, which can slow down the accumulation of bacteria, slow down the epidemic speed and postpone the peak of disease epidemic. Vertical drug resistance is mainly manifested as allergic necrosis reaction, which is used to reduce the amount of bacteria from the initial source of infection and delay the epidemic peak.