Food industry: people know that some microorganisms are beneficial to people through observation and research, and using them can improve our lives. For example, brewing wine, making soy sauce, vinegar, moldy tofu, pickles, dairy products, bread, steamed bread, bacon and so on. It's all about microbes. Among them, the principle of making dough with yeast is that yeast decomposes sugar in flour and discharges carbon dioxide. Carbon dioxide expands rapidly when heated, making steamed bread and bread loose and porous. Agriculture and Forestry: The varieties of agriculture and forestry have been improved to improve the quantity and quality of products, and the magnifying glass and microscope have also been fully used, such as hybrid rice planting in Yuan Longping. Hybrid rice should be carried out on the stamens of rice flowers. The flowers of rice are very small, so it is necessary to look for male sterile wild rice with magnifying glass and microscope for hybridization. The successful planting of hybrid rice not only solved the food problem of our people to a great extent, but also solved the global food problem in 2 1 century. Soil improvement and purification: There are many microorganisms in the soil, mainly bacteria, fungi, actinomycetes, algae and protozoa, which are related to soil fertility. Some of them can decompose biological corpses into nutrients needed by plants, while others can live with living things and play a role in nitrogen fixation. For example, many small balls growing in the roots of leguminous plants are rhizobia, which absorb and fix nitrogen in the atmosphere and provide it to plants as fertilizer, while absorbing carbohydrates from plants as their own nutrition. Scientific research has proved that each hectare of soybean can fix 102 kg of nitrogen in its lifetime (converted into sulfuric acid hinge is 5 10 kg). Therefore, people compare the root nodules of leguminous plants to ingenious biological nitrogen-fixing plants. If there are a large number of rhizobia in the soil, less or no nitrogen fertilizer can be applied, which can improve soil fertility, save electricity needed for nitrogen fertilizer production and reduce water quality and soil pollution. In ancient times, the working people in our country knew that beans had the function of fertile fields and were cultivated and used in large quantities artificially. A few days ago, in the development and construction of western China, some agricultural microbiologists strongly advocated that leguminous trees and grasses should be planted in deserts, Gobi and barren slopes in the west to increase soil fertility, green barren hills and barren slopes, prevent soil erosion and promote the development of agriculture, forestry and animal husbandry.
Clone:1In the summer of 996, Su Gezhu gave birth to a sheep named Dolly. In order to cultivate Dolly, study
The researchers first took out an egg cell from a ewe and removed its nucleus, then transplanted the nucleus of a 6-year-old adult ewe somatic cell into an enucleated egg cell, and finally transplanted the egg cell into the uterus of a third sheep. Five months later, Dolly was born. It is genetically the same as the 6-year-old adult ewe that provided the nucleus, and Dolly is the clone of that sheep. In the process of cultivating Dolly, scientists adopt somatic cell cloning technology, which is mainly divided into four steps:
① Breast cells were taken from the mammary glands of a 6-year-old female FenDorset white-faced sheep (called A) and put in a low concentration medium, and the cells gradually stopped dividing, which was called donor cells.
② An unfertilized egg cell was taken from the ovary of a Scottish black-faced ewe (called B) and enucleated immediately, leaving a seedless egg cell, called the recipient cell. ③ The donor cells and recipient cells were fused by electric pulse method, and finally the fused cells were formed. Electrical pulse can produce a series of reactions similar to natural fertilization, which can make the fused cells divide and differentiate like fertilized eggs, thus forming embryonic cells.
④ Embryonic cells were transplanted into the uterus of another Scottish black-faced ewe (named C), and the embryonic cells further differentiated and developed, eventually forming Dolly sheep.
In other words, Dolly has three mothers: its "genetic mother" is a Dorset white-faced ewe in Finland (A); Scientists took out the mammary gland cells of this sheep and transplanted their nuclei into the eggs of the second "borrowing mother", that is, an enucleated Scottish black-faced sheep (B), which fused, divided and developed into embryos. Then transplanted into the uterus of the third sheep (C) "surrogate mother" and developed into Dolly.
Theoretically speaking, Dolly inherited the genetic characteristics of sheep (A) which provided somatic cells. That is a white-faced sheep, not a black-faced sheep. The determination of molecular biology also shows that it has exactly the same genetic material as the sheep that provided the nucleus (completely, completely the same nuclear genetic material). There is also a very small amount of genetic material in the mitochondria of cytoplasm, which is inherited from the recipients who provide oocytes. They are like twins separated by six years.