Abamectin

Avermectin B1 (Abamectin) is a widely used insecticide and anthelmintic. IC50 Value: N/ATarget: AntiparasiticAvermectin B1 is a mixture of avermectins containing more than 80% avermectin B1a and less than 20% avermectin B1b. These two components, B1a and B1b have very similar biological and toxicological properties. The avermectins are insecticidal and antihelmintic compounds derived from various laboratory broths fermented by the soil bacterium Streptomyces avermitilis. Avermectin B1 is

The producing bacteria are produced by Streptomyces avermitills. It is a new species of Streptomyces, which belongs to Streptomyces griseus (melbeycin-like producing bacteria are Streptomyces hygroscopicus). The form is aerial mycelial branching, and spores generally appear on oat agar, glycerin, aspartin, inorganic salts, starch, and egg white agar. Observed by an electron microscope, the spore filaments began to be tight spirals, and gradually loosened later. The spore chain generally has more than 15 spores, which are round to oval and have a smooth surface. The selection of strains is very important. Different Avermectin producing strains make the content of each component of the fermentation broth different. The selection of new high-yielding strains not only increases the total unit of Avermectin, but also significantly increases the proportion of B1 components. Preservation of strains Avermectin-producing bacteria grow on the slope of YMS (yeast extract 4.0g, wort 10.0g, soluble starch 4.0g, agar 20.0g, water 1000mL, pH=7.4), and then put the spores in 20% aqueous glycerol solution Store at -30℃. Two mediums are generally used for seed preparation. The composition in 1000 mL water is as follows. A: Cerelose 1.0g, soluble starch 10.0g, beef extract 3.0g, Ardamine PH 5.0g, NZ-Amine E 5.0g, MgSO4.7H2O 0.05g, KH2PO4 0.182g, Na2HPO4 0.190g, CaCO3 0.5g, pH=7.0. B: Lactose 20.0g, distillers' Solubles 15g, Ardamine PH 5.0g, pH=7.0. The glycerol spore storage solution was inoculated into the above-mentioned seed culture solution, cultured at 28°C for 1 to 2 days, and then inoculated into the fermentation medium. The inoculation volume is usually 3% to 5%. Biosynthesis Biosynthesis can use the following fermentation media. A: Amidax 40g, distillers' Solubles 7g, Ardamine PH 5g, CoCl2·6H2O 0.05g, water 1000mL, pH=7.3. B: Cerelose 45g, Prepionlzed milk nutrient 24g, Ardamine PH 2.5g, polyethylene glycol P-2000 2.5mL, water 1000mL, pH=7.0. Studies have shown that the production of Avermectin is related to the following factors: ① strains. Strain selection can not only improve the fermentation units produced by microorganisms, but also change the ratio of each component, thereby increasing the content of the required components. It is reported that the addition of methyltransferase inhibitors such as Slnefungin and S-adenosyl methione also The ratio of B and A in the product can be changed; the morphology of the species should be selected for fermentation with full hyphae (PAMcCann uses medium of dextrin 0.4%, meat extract 1%, yeast 0.4%, agar 2%, pH=7.0 ). ②C/N ratio. Has a great impact on yield and composition. ③ Defoamer. Polyethylene glycol is a good defoamer, it can not only improve the fermentation unit, but also inhibit the production of an orange wax in the fermentation process. ④ Stir. It has a great influence on the fermentation effect. Since the mycelium is more sensitive to the impeller shear, the use of hydrofoil wheel stirring device can improve the oxygen supply and increase the output. ⑤ Inorganic salt. Various other inorganic salts have no beneficial effect on fermentation.

Avermectin has a good control effect on the pests of citrus, vegetables, cotton, apples, tobacco, soybeans, tea plants and other crops and delays drug resistance. Avermectin is a sixteen-membered macrolide with strong insecticidal, acaricidal, and nematicidal activity, a dual-purpose antibiotic for agriculture and livestock. Broad spectrum, efficient and safe. It has stomach poisoning and contact killing effect, and cannot kill eggs. Its mechanism of action is to interfere with neurophysiological activity and affect chloride transmission in cell membranes, and GABA is its site of action. When the agent stimulates the site of action, the transmission of motor nerve information is blocked, so that the signals of the central nervous system of the insect Chemicalbook are continuously accepted by the motor neurons. Insects are rapidly dehydrated, so the lethal effect is slow, and generally die after 24 days. It is used to control Plutella xylostella, cabbage worms, armyworms, beetles and other pests on crops such as vegetables and fruit trees. It is especially effective against pests that are resistant to other pesticides.