Detailed data of cyanobacteria

Cyanobacteria, also known as blue-green algae, is a large single-celled prokaryote with a long history of evolution. It has negative Gram staining, no flagella, chlorophyll a, but no chloroplast (algae different from eukaryotes), and can produce oxygen for photosynthesis. Different from photosynthetic bacteria, photosynthetic bacteria (Rhodosporus) carry out primitive photosynthetic phosphorylation, are anaerobic organisms in the reaction process, and do not release oxygen, while cyanobacteria can carry out photosynthesis and release oxygen. Its development makes the whole earth's atmosphere develop from anaerobic state to aerobic state, thus giving birth to the evolution and development of all aerobic organisms. Up to now, 120 kinds of cyanobacteria have nitrogen fixation ability, especially Azolla, an aquatic fern symbiotic with ANABAENA manjiangensis, is a good green manure. However, some cyanobacteria are polluted by nitrogen, phosphorus and other elements, resulting in eutrophic seawater "red tide" and lake "water bloom", which brings serious harm to fishery and aquaculture. In addition, some aquatic species, such as Microcystis, can produce toxins that can induce human liver cancer. Cyanobacteria are widely distributed in nature, including all kinds of water, soil and some internal and external organisms, and can even be found on rock surfaces and other harsh environments (high temperature, low temperature, salt lakes, deserts, ice sheets, etc.). ), and they are called "pioneers". They play an important role in rock weathering, soil formation and water ecological balance. In addition, cyanobacteria also have certain economic value, including many edible species, such as Nostoc commune (Nostoc commune), Spirulina platensis, Smahima and so on. At present, the latter two have been developed into "Spirulina" products with certain economic value.

Basic introduction of Chinese name: Latin scientific name of cyanobacteria: cyanobacteria alias: cyanobacteria, cyanobacteria, myxoalgae kingdom: cyanobacteria kingdom: cyanophyta: divided into chromococcus and algae: prokaryote chlorophyll: propagation mode with chlorophyll a and without chlorophyll b: asexual propagation or asexual propagation sporulation English name: blue-green algae classification, morphological characteristics, distribution range, propagation method, main value and harm. Algal cells are single cells or groups; The phycomycetes are filamentous and have phycomycetes. Cyanobacteria appeared on the earth about 3.5 ~ 3.3 billion years ago. There are about 2,000 known species of cyanobacteria in China, and about 900 recorded species. Morphological characteristics Cyanobacteria have no organelles such as chloroplast, mitochondria, Golgi apparatus, centrosome, endoplasmic reticulum and vacuole, and the only organelle is ribosome. It contains chlorophyll a, chlorophyll b, lutein and carotene, and phycobiliproteins (phycoerythrin, phycocyanin and allophycocyanin). There are chlorophyll a and photosystem ⅱ in its photosynthetic system, and water is used as electron donor to release O 2, while other photosynthetic bacteria generally use H 2, H 2 S and S as electron donors and do not produce oxygen. Generally speaking, cells containing chlorophyll a and phycocyanin are mostly blue-green. Similarly, there are a few species that contain more phycoerythrin, and the algae are mostly red. For example, a blue-green algae born in the Red Sea is called Chaetomium rubrum. Because it contains a lot of phycoerythrin, the algae are red and reproduce quickly, so the sea water is also red, hence the name of the Red Sea. Although cyanobacteria have no chloroplasts, it can be seen under the electron microscope that there are many photosynthetic lamellae in the cytoplasm, called thylakoids, and various photosynthetic pigments are attached to them, which is a membrane structure containing pigments, which greatly increases the membrane area in cells. The main function of this structure is photosynthesis. The chemical composition of the cell wall of cyanobacteria is similar to that of bacteria, and the main component is peptidoglycan (a compound formed by sugar and polypeptide). The stored photosynthetic products are mainly cyanobacteria starch and cyanobacteria particles. The cell wall is divided into two layers, the inner layer is cellulose, and a few people think it is pectin and hemicellulose. The outer layer is a colloid sheath, mainly pectin or a small amount of cellulose. There are many concentric annular membrane layers in cytoplasm, called thylakoids, in which photosynthetic pigments and electron transfer chains are located. The center of cyanobacteria is brighter than the surrounding protoplasm layer under light microscope, which is the location of genetic material DNA, equivalent to the nuclear region of bacteria, and is called centrosome or centrosome. "Centrosome" is usually not located in the center, and there is no obvious boundary with the surrounding cytoplasm. The DNA of cyanobacteria is almost * * *, which can be replicated continuously. The average content of DNA is more than that of higher animal cells. When cyanobacteria cells divide, new transverse walls grow inward in the middle of the cells, dividing cytoplasm and protoplasm into two halves. Generally speaking, two daughter cells are surrounded by a male glial sheath, and constantly divide into filamentous, flaky and other multicellular groups. In addition, cyanobacteria can proliferate by budding, breaking and re-dividing. The inner wall can continue to secrete colloid and increase into the rubber sheath. Some kinds of rubber sheaths are very firm and dense, and can be layered. Some kinds of rubber sheaths are easy to hydrate, and rubber sheaths of adjacent cells can dissolve each other. There may be non-photosynthetic pigments such as brown, red and gray in the rubber sheath. Cyanobacteria have single cells, colonies and filaments. The simplest is a single cell. Some unicellular organisms become groups because the daughter cells are embedded in the gelatinized mother cell wall after cell division. If they divide repeatedly, there will be many cells in the group, and the larger group can be divided into several smaller groups. Some single-celled organisms are polarized at the bottom and top because of their attachment to life. Filaments are formed by repeated division of cells along the same division plane and connection of daughter cells. Some filaments have the same cells, and some filaments have idioblast differentiation; Some filaments have false branches or true branches, and some cells at the top of filaments gradually become trichomes, which is also called polar differentiation. Filaments can also be connected into a group and wrapped in the colloid sheath of the male, which is a group of multicellular individuals. It is widely distributed all over the world, but most of it (about 75%) is fresh water and a few are seafood. Some cyanobacteria can live in hot springs at 60 ~ 85℃; Some species are related to fungi, mosses, ferns and gymnosperms; Some can also penetrate into calcareous rocks or shells (such as calcareous algae) or deep soil (such as soil cyanobacteria). Breeding methods There are two breeding methods for cyanobacteria. One is vegetative propagation, including direct cell division (fission), population disruption and filamentous algae production. The other is that some cyanobacteria can produce endospore or ectospores for asexual reproduction. Spores have no flagella. By 20 18, cyanobacteria have not been found to have real sexual reproduction. The main value of cyanobacteria is the earliest photosynthetic oxygen-releasing organism, which has played a great role in transforming the earth's surface from anaerobic atmospheric environment to aerobic environment. Many cyanobacteria (such as ANABAENA) can directly fix nitrogen in the atmosphere (reason: it contains nitrogenase, which can directly carry out biological nitrogen fixation) to improve soil fertility and increase crop yield. There are also cyanobacteria for people to eat, such as the famous Nostoc flagelliforme and Nostoc commune (Nostoc commune), Spirulina and so on. Chemists at the University of California, Davis have genetically engineered cyanobacteria to produce butanediol, a precursor chemical used to make fuels and plastics, and the first step to produce biochemical raw materials to replace fossil fuels. Related papers were published in the Journal of the National Academy of Sciences on October 7th, 2065438+2003/KLOC-0. Shota, the first author of the paper and an associate professor of chemistry at the University of California, Davis, said: "Most chemical raw materials come from oil and natural gas, and we need other resources." The US Department of Energy has set a goal that by 2025, 65,438+0/4 industrial chemicals will be produced by biological processes. Biological reactions will form carbon-carbon bonds, using carbon dioxide as raw material and sunlight to provide energy for reactions, which is photosynthesis. In this way, cyanobacteria have lived on the earth for more than 3 billion years. Using cyanobacteria to produce chemicals has many advantages, such as not competing with humans for food, and overcoming the shortcomings of producing ethanol from corn. However, the use of cyanobacteria as chemical raw materials is also a difficult problem, that is, the output is too low to be transformed. Using the online database, the research team found several enzymes that can carry out the chemical reaction they are looking for. They introduced DNA (deoxyribonucleic acid) that can synthesize these enzymes into cyanobacteria cells, and then gradually constructed a "three-step" reaction path, enabling cyanobacteria to convert carbon dioxide into 2,3-butanediol, a chemical used to make paints, solvents, plastics and fuels. Shota said that these enzymes may work in different ways in different organisms. It is impossible to predict the operation of the chemical path before the experimental test. After three weeks' growth, this cyanobacteria culture medium can produce 2.4 grams of 2,3-butanediol per liter, which is the highest yield achieved by using cyanobacteria in chemical production so far, and it also has great commercial development potential. Womei Xiangtai's laboratory is cooperating with Japanese chemical manufacturer Asahi Kasei, hoping to continue to optimize the system, further increase the output, conduct experiments on other products, and explore ways to expand this technology. Harm of Green Tide In some nutrient-rich water bodies, some cyanobacteria often multiply in summer, forming a layer of blue-green floating foam on the water surface, giving off a stench, which is called "water bloom", and the large-scale outbreak of cyanobacteria is called "green tide" (corresponding to the red tide in the ocean). Green tide causes the deterioration of water quality, and when it is serious, it will exhaust the oxygen in the water, leading to the death of fish. More seriously, some kinds of cyanobacteria (such as Microcystis) also produce microcystins (MCs for short), and about 50% of the green tide contains a lot of MCs. MCs is not only directly toxic to fish, humans and animals, but also an important cause of liver cancer. MCs is heat-resistant and difficult to be decomposed by boiling water, but it can be adsorbed by activated carbon, so it can be used to purify the polluted water source with activated carbon water purifier. Cyanobacteria bloom Cyanobacteria and other algae are food for silver carp and bighead carp, which can control algae and prevent cyanobacteria from erupting (non-classical biological manipulation). When a large number of cyanobacteria appear, the nearby water body is generally blue or green, and the water surface is covered by thick blue-green lake indigo, which is blown to the shore by the wind to accumulate. Not only do cyanobacteria cells containing toxins float in the water, but also when they are complexed with some suspended substances or preyed by aquaculture, they will precipitate with their excreta and accumulate at the bottom of fish ponds, which will have a huge negative impact on the production of pollution-free aquatic products. Chlamydomonas in cyanobacteria can quickly produce lethal factors, destroy gill tissue of cultured objects, interfere with normal metabolism, paralyze nerves and make them die. Individual species in cyanobacteria not only carry toxins in living bodies, but also decompose dead individuals to produce biological toxins-cyanobacteria toxins (such as microcystins). A large number of cyanobacteria toxins can directly lead to poisoning and death of cultured objects; Or even if the number is small, it can harm the breeding object through the accumulation effect of the food chain until it harms the human body. Firstly, spraying zeolite powder 10kg/ mu in the whole pond to flocculate cyanobacteria; Second, after an interval of 3-4 hours, spray the whole pond with Bacillus alginolyticus (Bacillus laterosporus) at a dose of 500g/mu. In the process of using microbial inoculants, attention should be paid to prevent the crab pond from lack of oxygen. It is not suitable to use it when the weather is sultry, and the aerator should be started when using it. Third, balance the ratio of nitrogen and phosphorus, change the ratio of nitrogen and phosphorus by spraying inorganic phosphorus, accelerate the rapid growth of beneficial algae such as green algae and diatoms as dominant algae species, and inhibit the growth of cyanobacteria, thus improving the over-growth of cyanobacteria. Due to the growth restriction of other algae species, it is impossible for cyanobacteria to erupt on a large scale at room temperature. When the water temperature is 25-35℃, cyanobacteria will grow faster than other algae, so temperature is one of the main factors of cyanobacteria outbreak. Eutrophication of aquaculture water makes cyanobacteria grow more easily, so ponds that don't change water often are more prone to cyanobacteria outbreaks. Organic phosphorus is a necessary factor for the growth of cyanobacteria, and the most direct and fundamental way to control cyanobacteria is to remove organic phosphorus. Eutrophication is the cause of cyanobacteria outbreak. Excess nutrients mainly come from the following aspects: 1. Chemical fertilizer is the main source of nutrition in many eutrophic areas. For example, in the Mississippi River basin, 67% of nitrogen flows into the water body, followed by the Gulf of Mexico, and more than 50% of nitrogen in the Baltic Sea and Taihu Lake also comes from the loss of chemical fertilizers. Blue cocci 2. Domestic sewage, including human domestic sewage and phosphorus-containing detergent. 3. Livestock and poultry breeding, livestock and poultry manure contains a lot of nutrient wastes such as nitrogen and phosphorus, which can lead to eutrophication of water bodies. 4. Industrial pollution, including fertilizer plants and wastewater discharge. 5. Burning fossil fuels, about 30% of nitrogen in the Baltic Sea and about 13% of nitrogen in the Mississippi River come from this. 6. Cyanobacteria make water anoxic, leading to animal death. Decomposition consumes oxygen, leading to a vicious circle of toxins. Cyanobacteria is the scientific name of cyanobacteria. There are many kinds of cyanobacterial toxins in some specific areas, which can be divided into hepatotoxin and neurotoxin according to their harm modes. They are known toxins that can attack the liver and nerves, and another toxin has a * * effect on the skin. When cyanobacteria cells rupture or die, toxins will be released into the water. When exposed to lake water containing cyanobacteria toxin, although some people will get sick, drinking water containing polluted algae may not necessarily lead to death. Long-term exposure to water containing cyanobacteria hepatotoxin, even if the content is low, may have long-term or chronic adverse effects on human body. If you continuously ingest water, fish or other aquatic products containing cyanobacteria, you may have headache, fever, diarrhea, abdominal pain, nausea or vomiting. If you swim in polluted water, your skin may itch, or your eyes and skin may get * * *. If you suspect that you have had an adverse reaction due to direct contact with polluted water, rinse your body with clean water and contact your doctor immediately. Boiled water will not remove the toxins from cyanobacteria, because you can't detect the presence of toxins by the appearance, smell or taste of water, only chemical detection can. If conditions permit, do not wash clothes and tableware with contaminated water. If there is no other water source, rubber gloves must be worn when using water at home. Bathing with contaminated water should be avoided, because direct contact with water can cause skin * * * and rash. ) Cyanobacteria toxin is soluble in water and heat-resistant. Soluble in water, methanol or acetone, non-volatile, resistant to PH change. The molecular formula of MC-LR is C49H74N 10O 12, and its molecular weight is 995.2 (often calculated as 1000). Its solubility in water is greater than 1g/L, and its chemical properties are quite stable. The natural degradation process of microcystins in water is very slow. When the content of microcystins in water is 5ug/L, only 10% is absorbed by particles in water after three days, and 7% is precipitated with sediment. Microcystins have high heat resistance and cannot be destroyed or removed by heating and boiling. Coagulation, sedimentation, filtration and chlorination of tap water can not remove it. A survey showed that low concentration of microcystins (128 ~ 1400 ng/L) were detected in the effluent of three water plants around the lake. The results showed that the microcystins in drinking water could not be completely removed by conventional disinfection treatment. It is a hepatotoxin and a strong promoter of liver cancer. After drinking water containing microcystins, domestic animals and wild animals will have symptoms such as diarrhea, fatigue, anorexia, vomiting, drowsiness, increased mouth and eye secretions, and even death. Pathological changes include liver enlargement, congestion or necrosis, enteritis bleeding, pulmonary edema and so on. Microcystins are also very harmful to human health. The LD 50 of MC-LR is about 50~ 100 ug/kg. When people take a bath, swim and do other water recreation, skin contact with water containing microcystins will cause sensitive parts (such as eyes) and skin allergies; A small amount of drinking can cause acute gastroenteritis; Long-term drinking may lead to liver cancer. Epidemiological studies show that chronic microcystin poisoning has caused serious liver damage to fishermen in Chaohu Lake. Medical departments found that microcystins in drinking water have a great correlation with the incidence of primary liver cancer in the population. 1996 caused acute liver failure in Brazil 100, and at least 50 people died within 7 months due to the acute effect of microcystins, which attracted worldwide attention. Cyanotoxin in fresh water has become a global environmental problem, and cyanotoxin poisoning incidents often occur all over the world. Uv-b (ultraviolet b-band, wavelength 275 ~ 320 nm, also known as medium wave erythema effect ultraviolet. Moderately penetrating, most of UVB contained in sunlight is absorbed by the ozone layer, and less than 2% can reach the earth's surface, especially in summer and afternoon. ) can destroy the mobility and phototaxis of cyanobacteria, and can affect many other physiological and biochemical processes, thus leading to the reduction of productivity and the destruction of germination and differentiation. Photosynthetic pigments will be bleached by UV-B, and the structure of light trapping complex will be affected, which will damage photosynthesis. The main sites of DNA and protein and the enzymes in nitrogen metabolism show different sensitivities to UV-B. UV inhibits the activities of nitrogenase and glutamyl ammonia synthetase, but increases the activity of nitrate reductase (when exposed to UV-B). Uv-b will also affect the basic photosynthetic reaction and the absorption of carbon dioxide. Synechococcus can resist ultraviolet rays by rapidly changing the forms of enzymes in the photosynthetic system. The plasticity of this molecule is very important to resist UV-B at the population level, which makes the sensitivity of photosynthetic system to UV-B change every day. However, photosynthesis can be activated by UV-A combined with blue light. Cyanobacteria have made countermeasures against the influence of UV-B, which include: a, producing light protection substance B similar to MAAs, escaping from UV c by moving away from light, producing quenching substances such as carotenoids and superoxide D, repairing DNA through mechanisms similar to light activation and light independence, and activating antioxidant enzymes. Uv-b induces many cyanobacteria to produce MAAs. In ANABAENA, only 290nm light can induce MAAs. In addition to light protection, MAAs can also adjust osmotic pressure and frost resistance. Other UV-A activators were also found. A database of photoprotective substances in cyanobacteria and algae has been established. Antarctic cyanobacteria form a large cattail community. Uv-b has a strong photochemical inhibition on the colony of Leptolyngbya, but it is not as strong as the inhibition on Phormidium. The latter contains 25 times more MAAs and 2 times more carotenoids than the former. Rai and his colleagues studied the effect of the relationship between UV-B and heavy metal pollution on nitrogen fixation, and found that they had a synergistic effect. On May 28th, 2007, a large area of cyanobacteria broke out in Taihu Lake, Wuxi, causing serious pollution of tap water and looting of pure water in urban areas. Although measures were taken in time, it had a great impact on people's lives. 2010165438+129 October, the blue algae bloomed in Dianchi Lake, Kunming, Yunnan, and the lake looked like green paint on the bank of the ridge line of Dianchi Lake in Kunming. The rolling green waves of the lake rushed to the shore, bringing a stench. Dianchi Lake is the most polluted of the nine plateau lakes in Yunnan. Whenever the temperature rises and eutrophication is serious, cyanobacteria will erupt, causing serious pollution. On August 20 1 1, 2 1, due to the continuous high temperature, cyanobacteria on some lakes in Chaohu Lake, Anhui Province began to "rise" again, and a large area of cyanobacteria gathered. Chaohu City pays close attention to the quality of urban centralized drinking water sources, and carries out measures such as interception and salvage of cyanobacteria and advanced treatment of tap water. Since 2008, Qingshan Lake, a landscape lake with a large water area within the urban area of Nanchang City, has been invaded by cyanobacteria for six consecutive years, especially 20 14, with dozens of cyanobacteria outbreaks. 20 14,10127 October, although it has entered late autumn and the temperature is low, cyanobacteria still broke out on the lake surface of Qingshan Lake. Hundreds of acres of lake seem to have been splashed with green paint, and the foul smell comes with the wind, and many people cover their noses. It is reported that in the past six years, Nanchang City has invested quicklime and bio-regenerative bactericide to purify lakes and kill cyanobacteria, but the results have been minimal. 20 16, 17 In July, Utah Poisoning Control Center received more than 100 poisoners, who were accompanied by vomiting, diarrhea, high fever, skin or eyes * * *, allergies and other symptoms. It is found that this phenomenon may be related to the explosive growth of cyanobacteria cells in utah lake. The area of cyanobacteria in utah lake accounts for 90% of the total area of the lake. Although the area is shrinking, it is actually more dangerous. Corresponding measures have been taken at all levels. * * * personnel said that 20 17 could not confirm the direct relationship between cyanobacteria outbreak and these symptoms, but the symptoms were consistent with those of cyanobacteria cell poisoning. According to the regulations of the World Health Organization and Utah Ministry of Health, the moderate risk standard of cyanobacteria cell number is 654.38+ million. On July 14, lake water sampling found that most samples exceeded the standard by 3 times, and one sample even contained more than 700,000 cyanobacteria cells. When cyanobacteria cells die, they will release more toxic substances into the water, which will reduce the number of toxic cells in the water, but it will be more deadly.