Before reading this article, please click "Follow", which is not only convenient for you to discuss and share, but also brings you a different sense of participation, thank you for your support.

Review

Yeast, a seemingly ordinary creature, is in fact a powerful one. In our daily life, yeast is widely found in foods such as bread and steamed buns, adding a unique flavor and texture to them. However, the world of yeast is far more complex and mysterious than we think.

Scientists have found that there is also a "dark side" to yeast, which is widely used in humans, and that yeast can have competitive-killer properties, in some cases releasing a toxin that can kill similar or even other microorganisms.

Cannibalistic yeast

In nature, competition is prevalent, both within and outside the population, and yeast is no exception. The yeast population is quite large, and more than 1,500 different types of yeast have been discovered, but only a few of them can be used to make wine and make bread and steamed bread and other pasta.

In some cases, yeasts secrete a toxin that kills their own kind in the body during their reproduction and growth, which is called "toxin", and the yeast that secretes the toxin is called "noxophile". In 1963, Makower and Bevan first discovered this phenomenon in Saccharomyces cerevisiae.

At present, the presence of cidal strains has been found in the brewing process of wine, beer and sake, and the gerid-loving strains have been isolated in several genera such as Saccharomyces globulus, Candida, Will's yeast and Cryptococcus cerevisiae.

For example, brewer's yeast will release toxic proteins into the body when it grows to the exponential stage, that is, the rapid reproduction period after adaptation to the environment, and the pH value is between 2.9 and 4.9, and almost no release is released during the quiescent period.

Biologically, yeasts that can produce toxins and can kill related strains are called "susceptible yeasts", strains that can be killed by toxins are called "sensitive yeasts", and yeasts that cannot kill other strains and cannot be killed by toxins are called "neutral yeasts". Different types of yeast secrete different toxins with different activity and immunity to different types of toxins.

According to the characteristics and immunity of different toxins, Saccharomyces sinensis can be divided into 11 types from K1 to K11.

Toxin-producing environment

In 1979, Bussey and Palfree refined the K1 grape juice yeast toxin and found that the toxin was a small protein with a molecular weight of about 11,500 Da. In its amino acid sequence, there are 5 molecules of tryptophan, which lacks arginine and proline, and usually coagulates with the mannanan components of the yeast cell wall to form an uneven large aggregate.

Different types of toxins have their most suitable active environments, the most suitable pH range for K1 toxins is 4.6-4.8, and the most suitable pH range for K2 Saccharomyces cerevisiae toxins is 4.2-4.4.

In addition, toxinophilia is thermally unstable and generally inactivated above 40°C. Type K1 toxins are most stable at 25°C and type K2 are most stable at 30°C. At 26°C, K1 toxins can be inactivated by vigorously shaking them for 25 minutes or by adding proteases for a period of time.

However, there are also yeasts that are more adaptable to the environment. The toxins produced by Weil's yeast can tolerate an environment of 60°C, and the toxins of Hansen's yeast can tolerate 100°C.

In the culture medium of Saccharophilia, the amount of toxin protein produced is maximized at the optimal pH and temperature. When yeast paste and peptone are used as nitrogen sources, the amount of toxins produced can also be increased quickly, but excessive dosage will affect the formation of toxins.

After entering the logarithmic phase, the homicidal activity of the yeast was the strongest. At the same time, the corresponding sensitive yeasts are also the most sensitive to toxins. When entering the growth quiescent phase, the resistance of sensitive yeast to toxins will be enhanced, and the lethal effect of toxins on it will gradually weaken.

Application of Sacrificidal Yeast

In the wine industry, wild yeast can contaminate the fermentation process, resulting in low yields. For this purpose, specific strains of yeast can be cultivated to prevent contamination by wild yeasts. If the genes dominated by the killing yeast are transferred to the production yeast through transgenic breeding technology, it can also obtain the killing characteristics and achieve the effect of preventing pollution.

Saccharophilia can be used to identify strains. Yeasts used in industrial and medical applications are specific species that exhibit different susceptibility to different toxins, and this property can be used to identify specific yeast species.

Saccharotoxins can kill not only yeast species, but also many eukaryotic and prokaryotic microorganisms. As a result, scientists began to explore the possibility of using this toxin as an antifungal agent to fight infections with pathogenic yeast and other microorganisms. Recent research has made some progress in applying toxin-loving treatment to fungal skin infections and other issues.

However, there is still a problem to be solved, the activity of toxin is affected by factors such as the pH value and temperature of the environment in which it is located, and the human skin environment is different from its suitable pH value and temperature, and in order to effectively apply it in treatment, it is necessary to solve the problem of how to maintain its stability and activity in the human skin environment.

Of course, there are a large number of species of zygocide in nature. In the future, it is possible for scientists to isolate and breed strains that are more adaptable to a wider range and more stable to different pH values and ambient temperatures. This will open up a wider range of possibilities for the use of toxins in medical applications.

end

The discovery of bacidox has triggered a deeper exploration and thinking about the microbial world, and the toxin released by it has revealed the complex competition and survival in the microbial world.

This discovery not only deepens our understanding of yeast, but also brings new perspectives and opportunities to the field of biological sciences.

Saccharophile yeast not only has potential applications in the wine industry to prevent contamination by wild yeasts, but may also be a novel option for antifungal agents to treat pathogenic yeast and other microbial infections.

Although there are some technical challenges in the application process, these obstacles are expected to be gradually overcome with the continuous progress of science and technology.

Finally, due to the rules of the platform, you will only be considered a fan if you interact with me more. If you like my articles, you can click "Follow" and receive the article push as soon as you become a fan.