That's yeast - it mushrooms, you know, probably many.And what can we say about the future classification of these representatives of the kingdom?It is known that yeast fungi belong to Ascomycetes and Basidiomycetes card.What does this mean?Let's try to understand together.
yeast - mushrooms
And single-celled fungi.They have lost the mycelium as a result of evolutionary processes, according to in connection with the transition to life in liquid substrates that are rich in organic matter and are very favorable for the life of these organisms.Total yeast there are up to a thousand species.All yeasts - unicellular fungi.
Dimensions
Single detached cells of these fungi reach up to 7 microns in diameter, but some grow up to 40 micron.However, some yeast still form at the stages of their life cycle mycelium, and in some cases - the fruit body.Currently, for example, baker's yeast, is the first eukaryotic genome which has been identified and decoded.
bit of history
yeast - mushrooms, "domesticated" by man, and for quite some time.They have long, for thousands of years, is used for culinary purposes: baking, creating conditions of fermentation.Already in ancient Egypt, there were bakeries and, obviously, are used yeast.And in some countries in ancient times, along with cakes unleavened (eg matzo or pita) is gaining in popularity and production of leavened bread.Brewer's yeast is known to the Egyptians were more than six thousand years ago, and with the help of these people cooked organisms this foamy drink.
Interestingly, for the new leaven in many farms of old used the remnants of the old.So, according to scientists, it occurred breeding yeast species were not found in the wild.Many believe certain types of yeast product exclusively human activity (for example, varieties of cultivated crops: wheat, rye and other).
zymology
so-called science that describes and studies the life and work of these organisms.Yeasts are fungi, their pure culture was first isolated in 1881 in Denmark, and in 1883 she was already used to produce beer.At the end of the 19th century created the classification of yeast, and in the 20th century collection and appear determinants known cultures.Yeasts are fungi Ascomycetes division until the middle of last century.Scientists have observed their sexual cycle, summarizing how the taxonomic group (marsupials fungi).But in Japan, one of the scientists induced reproduction and Basidiomycetes yeast.Thus, experts have concluded that the yeast fungi (photo below) were formed in the course of evolution independently among the two divisions of the kingdom (ascomycetes and basidiomycetes).The data confirmed and molecular-biological study of organisms.They are not the taxon, but rather, a particular life form.
Ascomycetes and Basidiomycetes
Thus, yeast fungi are Ascomycetes and Basidiomycetes Division (or rather, to two different departments).All of them - subkingdom higher fungi.They can distinguish between the characteristics and life cycles of some other signs: pairs in the DNA, the presence of urease.Ascomycetes, or marsupials fungi - is extensive department, which includes up to thirty thousand species (by the way, the famous truffles belong to this department, as well as morels and lines).Among all - and yeast, which are considered by scientists for the second single-celled organisms.
Habitats
Typically, these organisms live in places that are rich in sugars - substrates on the surface of fruits and berries, leaves.They can feed on waste products of plants: nectar, secretions, wound juices.Do not disdain and dead phytomass.Can live in the soil bed of organic matter in natural water masses.Some yeasts present in the intestines of insects that feed on wood.Many yeast and leaves that are affected by aphids.
Application
Some types of yeast cultures have long been in demand in cooking, baking and forcing the production of alcohol.Kvass, bread, beer and wine can not do without these tiny assistants.All of these are known to mankind since ancient times, yeast fungi are Ascomycetes division.For the production of hard liquor, they participate in the distillation step fermentation.Now some yeast cultures are used in a wide range of biotechnology: the production of fuel and food additives and enzymes.In science they are used as experimental crops for genetics research.
Saccharomyces cerevisiae
- used in breadmaking culture Saccharomyces cerevisiae, known as baker's yeast.They produce alcoholic fermentation character, enhancing flavor and aroma of the bread products (alcohol, after, during baking, evaporates).In addition, carbon dioxide formed in the weight causes the dough to rise, making the dough porosity and softness.
- in nature on grapes naturally develop a yeast culture, which are visible as whitish plaque.But the true wine yeast is considered to be Saccharomyces cerevisiae, which are found in the clusters is quite rare.It is this variety and is used mostly for cooking wine material.As a result of the processing of sugars by yeast contained in the grape juice, produced ethanol and yeast in the amplification degrees - die.A champagne ready for the wine is subjected to re-fermentation by adding a yeast culture.
- The use brewing sprouted grains of barley (malt) and yeast and bottom fermenting.Malt is ground, boiled, mixed with water and is fermented using Saccharomyces cerevisiae or some other yeast species.Kvass produce about the same, but other than a yeast is used more and lactic acid bacteria.
- The above yeast, widely used in the national economy, belong to the order of fungi Ascomycetes.And popular beverage preparation Association of yeast and bacteria, for example, or Tibetan Kombucha mushroom.They have many useful properties for the human body, and the regular use of these drinks warn various diseases gastrointestinal tract and other internal organs.
