Elves in the sea and charming guests born in luminous capsules

The detection of anti-cancer fortune-telling gene knows in advance that the indestructible little creature water bear worm finds its way out from the gene. What effect does the clinical application of gene technology have on genes? Speaking of props you want most, what is it? The invisibility cloak must be a magic weapon that many people dream of. Although the so-called "optical camouflage" stealth technology often appears in various movies, novels and games, so far, human technology has not been perfectly realized. However, in nature, there have long been creatures with similar mimicry ability: for example, chameleons can change the color of their bodies and blend in with the background, or the magical Euprymna squid can shine to eliminate shadows. Thumb-sized Hawaiian short-tailed squid hides in the sand at the bottom of the sea during the day and only comes out to feed at night. If you look closely, you can find that they are just like the elves in the animation, emitting beautiful light. Because the shadows produced by swimming squid may expose their whereabouts to predators below, they simulate moonlight by emitting light to eliminate the shadows and avoid being preyed. However, the researchers found that what really glows is Vibrio Luminosus (Vibrio? Scheri) rather than the squid itself, and the luminous behavior is periodic day and night. How is this achieved?

There is a lot of bacterial exchange every day, mcfaul? Professor Ngai's team has been studying Hawaiian short-tailed squid for over 20 years. 65,438+05 years ago, it was known that this squid excreted 90% of Vibrio Luminosus in the luminous sac of its head, and then crawled into the sand at dawn. During the day, the number of bacteria will rise to the number of the previous night and continue to perform the luminous task. However, it was not until 20 10 that the research team explained this phenomenon from the change of gene circadian cycle by analyzing the transcriptome of squid and bacteria. It has been found that the activity of genes related to cytoskeleton destruction will increase by more than 50 times before squid secretes Vibrio Luminosus. Because the cilia structure on the cell surface is supported by cytoskeleton, these cilia will gradually disappear with the activation of genes; The space between cilia is the habitat of Vibrio Luminosus, so the bacteria will lose their dependence and squid can easily expel them. However, after the cleaning operation, the expression of the enzyme gene used by the remaining 10% photolytic Vibrio to decompose the host cell membrane will increase obviously, so the rich cell membrane left in the protocilia of squid cells can be turned into valuable. 12 hours later, genes related to chitin fermentation of photolytic Vibrio will be activated, further strengthening the population [note 1]. This series of changes has enabled squid to acquire the luminous ability of bacteria without being excessively eaten by whales; It can shelter the bacterial population from continuing and expanding its population, and the two species are skillfully maintained in a state of balance.

Who is the decider of the circadian cycle? The gene expression of the above two species has its own circadian cycle, but the researchers found that there is an inseparable relationship between them. Sepiella maindroni expresses cry genes named escry 1 and escry2. These genes will change their activity with the change of light in the environment, and the protein transcribed by them can affect the diurnal cycle of other systems in the body. But mcfaul? Professor Ngai's research team found that the expression of escry 1 gene in nearby cells would not change with time if Vibrio luminescens was removed from luminescent capsules, which proved that the day-night circulation of squid must have * * * bacteria to function normally. In order to further explore the influence mechanism, the researchers mutated the lux gene of bacteria and deleted the luminescence function. It was found that the gene escry 1 of squid also lost its periodicity, indicating that the light emitted by bacteria is probably the key. When the researchers gave extra artificial blue light, the escry 1 gene resumed the day-night cycle; However, it is worth noting that if only the squid without * * * bacteria is given artificial blue light, the expression of escry 1 gene cannot change with the day and night, and the whole system can operate normally only if the molecules in the envelope of photolytic Vibrio coexist [Note 2]. Therefore, the diurnal cycle of the two species will not only affect each other, but even Vibrio Luminosus, as a tenant, still holds a certain dominance. Mcfaul? Professor Ngai believes that this phenomenon may also play an important role in other organisms. For example, there are actually more * * * bacteria in the intestines of mammals than the number of somatic cells. Therefore, in addition to directly affecting the host, the interaction network between various strains will certainly be much larger and more complicated.

Explore more genetic mechanisms related to * * * Traditionally, to study genetic mechanisms, we must first find out the changes in appearance or behavior, and then find out the corresponding mutated genes; Then take the gene out of normal organisms to see if the same change will happen. But this method is not only inefficient, but also if the gene continues to run normally, researchers will not be able to find abnormalities and may not even know where to start. However, with the development of technology in recent years, it is now possible to sequence the whole genome of an organism, and then compare them with each other to find out the differences. Bravo et al. compared 50 plant genomes by using this principle, and found 138 genes only found in plants with rhizobia, among which 15 genes have been found to be related to the mechanism of plants and rhizobia. In order to verify whether the remaining genes also play an important role in the growth of * * *, the research team selected seven other previously unknown genes to eliminate them, and found that once six of them were not expressed, plants could not establish a relationship with rhizobia, so they successfully discovered important achievements that the old methods could not find [Note 3]. However, just by comparing the existence of genes, it may still be impossible to find genes that also play an important role in the relationship between life and death, but exist in every plant; At this time, if combined with gene activity indicators such as transcript analysis, it may be possible to establish a more perfect gene interaction map and have a deeper understanding of gene regulation among * * * biological species.

References: 1. Wieram et al. American Academy of Sciences 2010; 107: 2259-64.2. Heath-Heckmanea et al. 4.3.Bravo A et al., NAT Plants 2016; 2: 15208.

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