256 results about "Logarithmic growth" patented technology

The invention provides a biocontrol bacterial strain for preventing and treating plant diseases and its bacterial agent, belonging to the field of biological control. The strains used are Gram-negative bacteria, identified as Lysobacter enzymogenes, and the strain code is OH11. Strain OH11 has no flagella but has slippage, can produce various extracellular hydrolytic enzymes including chitinase, β-1,3-glucanase and protease, and can effectively inhibit the growth of fungi and bacteria. The antibacterial zone diameters of strain OH11 against Sclerotinia sclerotiorum and Phytophthora capsici were both greater than 22.0 mm; the antagonism against potato ring rot was stronger, and the diameter of the inhibition zone reached 50 mm. The OH11 strain was inoculated into the seed tank, cultivated to the logarithmic growth phase, and the seed liquid was connected to the production tank for cultivation. The medium used in the production tank was the same as that of the seed tank. The liquid fermentation adopts aerobic submerged fermentation and fed-batch process, the dissolved oxygen is 15%-20%, the fermentation temperature is 30°C, the fermentation time is 72h, and the initial pH value is 7.5. After the fermentation is completed, the culture solution is taken out of the tank and directly packed into liquid dosage forms with plastic packaging barrels or packaging bottles, or subpackaged into solid dosage forms with peat adsorption packaging bags. The biocontrol strain OH11 can effectively control plant pathogenic fungi, bacteria, nematodes and other diseases, and the overall control effect is 50%-70%. In the greenhouse pot experiment, the control effects of OH11 on pepper blight and tomato bacterial wilt reached 83.6% and 86.4%, respectively. Strain OH11 has the characteristics of broad antibacterial spectrum, high activity, and environmental safety. In today's serious pesticide pollution, zymolysobacterium and its bacterial agent will be a good substitute.

The invention relates to a medical dressing with bioactivity and a preparation method of the medical dressing and belongs to the technical field of biomedical engineering and material science. The medical dressing with the bioactivity is used for covering skin defect wounds caused by burning, scalding, operation, wounds and diseases and inducing wound repair and is prepared as follows: one or more of embryonic stem cells, umbilical cord blood stem cells, amniotic fluid stem cells, peripheral blood stem cells and bone mesenchymal stem cells of humans or animals are cultured in vitro, stem cell growth factors secreted in the logarithmic growth phase are collected and mixed in proportion with one or more of I type collagen, III type collagen, chitosan, hyaluronic acid, chondroitin sulfate and sodium alginate, thin-layer sponge is taken as an inner layer, a porous high-polymer material film outer layer prepared from a mixture formed by one or more of PLA (polylactic acid), PGA (polyglycolic acid), PLGA (poly(lactic-co-glycolic acid)) and PCL (polycaprolactone) is attached, the product is frozen-dried and cut, and the medical dressing with the bioactivity is formed and used for treating skin defect wounds caused by burning, scalding, operation, wounds and diseases and inducing wound repairing.

A microencapsulation method of triple probiotics relates to a cell immobilization biological method. The method comprises the following steps: firstly, culturing triple probiotics to a logarithmic growth phase, preparing a soybean protein bacterial suspension; secondly, mixing the soybean protein bacterial suspension with gelatin to prepare a bacterial gel solution; thirdly, mixing the bacterial gel solution with sodium alginate, performing emulsification; fourthly, sprinkling a calcium chloride solution, performing a capsulation reaction; fifthly, spraying chitosan, performing further solidification; sixthly, washing with a calcium chloride solution, performing centrifugation, collecting capsules. The invention can perform simultaneous microencapsulation of three probiotics; A probiotic preparation prepared by the invention has very strong stress resistance, and can be colonized and grow in intestinal tracts more rapidly.

The invention discloses a preparation method and application of a classical swine fever virus recombinant subunit vaccine with the amino acid sequence shown as SEQ ID No.1. The preparation method of the classical swine fever virus recombinant subunit vaccine typically includes the following steps: classical swine fever E2 truncated protein (TE2) coding gene is cloned into baculovirus vector pFastBacTM1, and is then transfected into Sf9 insect cells to obtain recombinant baculovirus capable of expressing protein TE2. The high five insect cells in logarithmic growth phase are infected by the recombinant baculovirus, so that a large amount of the protein TE2 can be expressed in a cell culture supernatant. Finally, the cell culture supernatant is recovered and purified to obtain a large amount of the recombinant protein TE2 with the purity more than 90%. According to the method, the target protein can be harvested from the cell culture supernatant, the time of protein purification is reduced, consumption of a large amount of time can be avoided, and the vaccine production process can be simplified. Under the premise of simplification of the vaccine production process, the recombinant protein TE2 has the advantages of strong immunogenicity and high safety, and the animal experiments prove that the recombinant protein can effectively stimulate the body to produce a highly effective humoral immune response.

The invention relates to a reconstruction method of tissue engineering human corneal epithelium. The method comprises the following steps of: adopting a DMEM / F12 culture medium containing 20% calf serum to carry out the in vitro culture on human corneal epithelium cells to a logarithmic growth phase, and adopting trypsin and a trypsin-EDTA digestion method to obtain a digestive amniotic carrier bracket of which the epithelium is completely removed; and after the digestive amniotic carrier bracket of which the epithelium is removed is flatly laid in a plug-in Petri dish and is firmly and pasted in a drying way, inoculating the human corneal epithelium cells at the logarithmic growth phase suspended in the DMEM / F12 culture medium containing IV type collagen and 20% calf serum to the plug-inPetri dish flatly laid with the digestive amniotic carrier bracket of which the epithelium is removed, and carrying out the in vitro reconstruction on the tissue engineering human corneal epithelium by a gas-liquid interface culture method. The invention has scientific and reasonable process, the reconstructed tissue engineering human corneal epithelium can be used for mass production, a lot of demands of vast blind patients with corneal epithelium diseases for the tissue engineering human corneal epithelium in clinical corneal transplantation treatment can be met, and the costs of the in vitro reconstruction and clinical treatment of the tissue engineering human corneal epithelium are low.

The invention provides a culture method for increasing the yield of fucoxanthin contained in diatom. The culture method comprises the following steps of: (1) heterotrophically culturing activated diatom for 3-8 days so that the diatom is in a logarithmic growth period; (2) inoculating a diatom culture solution obtained from the step (1) in the logarithmic growth period as a seed solution into a heterotrophic culture vessel which contains a heterotrophic culture medium (culture medium I) according to 5%-50% volume of inoculation amount to carry out heterotrophic culture for 4-12 days at the temperature of 20-34 DEG C, wherein tomato extractives are added to the heterotrophic culture medium (culture medium I) obtained from the step (2). The culture method provided by the invention can enhance the biomass concentration of the diatom and increase the fucoxanthin content of a stable diatom body, thereby increasing the yield of the fucoxanthin contained in the diatom.

The invention belongs to the technical field of biological medicines and particularly relates to a detection method for anti-CD20 monoclonal antibody binding activities. The method comprises the following steps: a. taking a logarithmic growth phase high-expression CD20 cell, carrying out cell counting, and adjusting the cells to proper cell density for planking; b. carrying out series gradient dilution on a reference and a sample to be detected, and adding culture plates planked with the cells in sequence for a period of time; c. collecting the cells, and adding secondary antibody incubation marked with fluorescein isothiocyanate (FITC) for a period of time; and d. detecting by a flow cytometry to obtain the bonding activities of the sample to be detected. With the adoption of the detection method, the requirements in checking aspects of specificity, precision, linearity, range, accuracy and durability and the like can be satisfied; and the method can be effectively used for detecting the anti-CD20 monoclonal antibody binding activities.

Multicomponent vaccines are provided which aid in the prevention and treatment of staphylococcal infections and which include certain selected combinations of bacterial binding proteins or fragments thereof, or antibodies to those proteins or fragments. By careful selection of the proteins, fragments, or antibodies, a vaccine is provided that imparts protection against a broad spectrum of Staphylococcus and other bacterial strains and against proteins that are expressed at different stages of the logarithmic growth curve. In one embodiment of the invention, a composition is provided that includes a fibrinogen binding domain of a fibrinogen binding protein and a bacterial component such as a capsular polysaccharide, and both active and passive vaccines based on these components are also provided, along with methods of treating infection using these compositions and vaccines.

The invention discloses a method for obtaining extracellular water-soluble monascus yellow pigment through high-carbon source fermentation and application of the method. The method comprises the following steps of inoculating a monascus strain in a basic fermentation medium for aerobic fermentation to ensure that the monascus strain is in a logarithmic growth period or stable period; then, replenishing a carbon source, and further carrying out aerobic fermentation, wherein the concentration of the carbon source in the fermentation medium is at least 60g / L; and carrying out solid-liquid separation on the fermented fermentation solution, and extracting the liquid to obtain the extracellular water-soluble monascus yellow pigment. According to the method, the metabolism of monascus is optimized by using a direct high-carbon-source fermentation method, so that the extracellular water-soluble monascus yellow pigment with a high color value and high tone is obtained, and the natural water-soluble monascus yellow pigment is produced. The current process for producing the monascus yellow pigment by using a conversion method can be replaced with the method, so that adverse effects in chemical conversion steps can be eliminated; and the obtained pure-natural monascus yellow pigment product contains no artificially-modified structural components, so that the quality requirement for food safety is met, and the application prospect is wide.

The invention provides a method for large-scale preparation of micro-organism microcapsules, belonging to the technical field of micro-organism and biology. The method of the invention comprises the steps as follows: (1) capsule solution preparation: preparing the sodium alginate solution with the mass volume specific concentration of 1-2% w / v and carrying out the operation of sterilization; (2) preparation of curing agent: preparing the CaCl2 solution of 0.1-0.3mol / L and sterilizing; (3) preparation of the micro-organism microcapsules: micro-organism seed liquid with the logarithmic growth phase is added into the sterilization capsule solution till that the density of the solution is about 10<6>cfu / ml; the solution is then injected into the aseptic CaCl2 solution through the aseptic filter film and a nozzle by high-pressure air, then mixed and solidified till that supernatant is precipitated so as to gain the microcapsule and to wash the capsule; (4) after-covering culture: the microcapsules covered by micro-organism cells are arranged in fermentation broth and cultured till logarithm growth telophase, so as to gain the micro-organism microcapsule by filtration and separation. The method of the invention has the advantages of overcoming the defect that the micro-organism microcapsule which is prepared by covering-method before the sterilization can not be produced in large-scale, large production, simple operation and low cost of material and equipments.

The invention relates to a method for improving the percent conversion of a tylosin component A. With the method, streptomyces fradiae is used as a producing strain and is fermented to produce the tylosin by first-level seed tank fermentation culture, second-level seed tank fermentation culture and fermentation tank fermentation culture. The method is characterized in that nonionic surfactant of which the mass concentration is 0.5-2.5% is added into a fermentation culture medium after the fermentation tank fermentation culture enters a stable period after a logarithmic growth phase is finished. The nonionic surfactant is added into the culture medium during a fermentation culture period to the stable period so as to enhance the permeability of a mycelium cell, so that a metabolin in a cell is accelerated to quickly release out of the cell to relieve the feedback inhibition of macrosin methyltransferase and improve the enzyme activity, and finally, a tylosin component C is accelerated to quickly covert into the tylosin component A. The tylosin component A in the current industrial production generally accounts for 80-85%, and the content of the tylosin component A can finally achieve 90-94% according to the method disclosed by the invention.

This invention relates to surface properties of metallic materials EIS analysis. mCRR the transmission line model is firstly used to fit the electrochemical impedance spectrum measured under the conditions of satisfying causality, stability and linear, where m is a positive integer, C and R represents respectively pure capacitance and pure resistance; then the characteristic frequency f* of every Ci and Ri parallel branch is calculated respectively according the formula f*=1 / (2 pi CiRi) and the logarithmic chart of discrete parameters Ci and Ri distribution variable along to characteristic frequency under different serial research conditions and the chart of Ro variable to research condition. Finally, the characteristics difference of surface properties of metallic materials is determined according to chart characteristic.

The method of utilizing calcium alginate immobilized Diehliumyces pseudomnad R-8 in desulfurizing oil includes the following steps: preparing Diehliumyces pseudomnads R-8 of preservation number CGMCC0570 cell in logarithmic growth phase or quiescent phase; embedding the obtained Diehliumyces pseudomnads R-8 thallus with calcium alginate; amplifying and culturing the obtained immobilized cells, desulfurizing oil repeatedly. The said method has high activity of immobilized cells, high stability, easy recovering of biological catalyst for reuse, no pollution to oil product by the pigment produced in the desulfurization with free cell, and cheap and biocompatible calcium alginate used, simple technological process and low production cost, and may be used in industrial production easily.

The invention relates to a preparation method of an antibiotic medicine erythromycin high-efficiency degradation microbial inoculum. The method comprises the steps that: (1) active sludge is inoculated into a culture medium, and is acclimated with a gradient pressure acclimation method; after acclimation, the material is settled; upper-layer water sample is fetched; separation is carried out by using a coating separation method and a plate streaking method after gradient dilution; culturing and purification are carried out; the separated strain is inoculated into beef extract and peptone culture media, and is subjected to shaking culturing until a logarithmic growth phase is reached; and (2) the obtained strain is inoculated into a culture medium and is cultured, such that the microbial inoculum is obtained. The preparation method provided by the invention is simple and feasible, and has the advantages of high safety and low cost. The obtained erythromycin degradation microbial inoculum is convenient to use, and can degrade the antibiotic medicine erythromycin highly efficiently. The strain can easily be deactivated, and can be used in erythromycin effective removing in water treatments.

The invention provides two different composite microbial flora powders, wherein a microbial flora A comprises 40% of lacbobacillus helveticus and 60% of lacbobacillus fermentum; and the microbial flora B comprises 50% of bacillus subtilis and 50% of bacillus licheniformis. The application method comprises that: the microbial flora powder A is added into a feedstuff according to a proportion of 0.2-0.4%, and the microbial flora powder B is added into drinking water according to a proportion of 0.05-0.1%. A preparation method comprises the steps that: with a liquid fermentation method, soybean is adopted as a fermentation raw material; through twice amplification, various strains are respectively cultured to a logarithmic growth phase (pH value is 4-5); microbial powder with water content no higher than 5% and viable cell amount no lower than 108 / g is obtained through spray-drying; and the microbial powder A and microbial powder B are obtained. With the additives provided by the invention, poultry and livestock disease infection and spreading can be effectively prevented; poultry and livestock product meat quality can be greatly improved, poultry and livestock slaughter rate can be improved, the use of antibiotics and chemical additives is reduced, feedstuff and culture water are saved, and economic and social benefits are improved. The additives are ideal composite microbial feed additives.

The invention discloses a method for culturing human airway epithelial cells. The method comprises the following steps of: (1) acquiring human airway epithelial cells which are subjected to primary culture; and (2) acquiring human airway epithelial cells which are subjected to subculture, namely cleaning by using a phosphoric acid buffer solution when the fusion density of primary cells reaches 70 to 90 percent, adding a 0.25 percent trypsin solution, digesting at room temperature for 5 to 10 minutes, collecting cell suspension when cells are retracted and suspended, adding an equal amount of solution containing a protease inhibitor, performing centrifugal collection on the cells, inoculating in a novel culture dish containing a complete medium at the concentration of between 1 and 6*10<6> cells / ml, culturing, and thus obtaining the human airway epithelial cells which are subjected to subculture when the cells grow to a logarithmic growth phase after 3 to 5 days. The method for culturing the human airway epithelial cells has a stable technology and is high in repeatability; and the cultured cells have high purity and uniform morphology, grow well and can be subjected to continuous passage.

The invention discloses a judgment method and regulation and control method for the growth states of activated sludge. The judgment method includes the steps that the endogenous respiration rate OURe of the activated sludge is measured, a nitrogen containing solution or an autotrophic bacterium restraining solution and a carbon and nitrogen containing solution are added, the autotrophic bacterium respiration rate OURN and heterotrophic bacterium respiration rate OURC of the sludge are measured respectively, after the final autotrophic bacterium respiration rate OURA and the final heterotrophic bacterium respiration rate OURH are calculated, logarithms are taken respectively, an InOURA-time reciprocal diagram and an InOURH-time reciprocal diagram are drawn, and whether the growth states of two kinds of a logarithm increasing phase and a non-logarithm increasing phase are achieved or not is judged. The regulation and control method includes the steps that the quasi endogenous respiration rate OURme, the endogenous respiration rate OURe and the sludge nitrogen-added respiration rate OURN are measured respectively; a characteristic diagram is drawn, the growth state of autotrophic bacteria gets into the logarithm increasing phase by controlling alkalinity, and the growth state of heterotrophic bacteria gets into the logarithm increasing phase by increasing the volume of the sludge or the matrix adding quantity. The novel effective method is provided for judgment and regulation of the sludge growth situations of a sewage treatment plant.

The invention discloses a cultivation method of marrow dedifferentiated mesenchymal stem cell. The method comprises the following steps: carrying out Ficcol isolated culture on bone marrow to obtain mesenchymal stem cell, when the cell is in logarithmic growth phase, abandoning a mesenchymal stem cell culture medium until the cell density achieves 70-80%, replacing as an osteogenic induction culture medium to culture for 3-7 days, abandoning the induction culture medium, cleaning for three times by using PBS, cleanly eliminating the culture medium residual liquid, replacing the cell in the mesenchymal stem cell culture medium, replacing new culture medium per 2-3 days, when the cell overspread a culture dish, performing normal digestion passage treatment, and trypsinizing, wherein the digestion time is not over 1 min, further culturing after the cell passage till to the 12th-14th day. Compared with the traditional bone marrow mesenchymal stem cell, the method for acquiring the dedifferentiated mesenchymal stem cell by replacing the culture medium has improved propagation efficiency and the osteogenesis dedifferentiation capability is enhanced.

The invention provides a method for culturing spirulina by using livestock and poultry excrement wastewater, belonging to the fields of sewage treatment and algal culture. The method comprises the following steps: (1) pretreatment of livestock and poultry excrement wastewater: filtering, and sterilizing the filtrate to obtain a culture solution; (2) domestication of spirulina: inoculating an alga strain into fresh water or sea water, and performing domestication culture; (3) culture of spirulina: inoculating the spirulina in a logarithmic growth phase of the step (2) into the culture solution of the step (1), and culturing; (4) collection of spirulina: filtering the spirulina cultured in the step (3), cleaning, collecting the spirulina, and then drying the spirulina; and (5) filtrate recovery. The method provided by the invention solves the problems that the livestock and poultry excrement pollutes the environment and the spirulina culture cost is high. The method can realize the triple effects of protecting the environment, lowering the spirulina culture cost and producing nutrient substances required by human beings.

Belonging to the technical field of biological pesticides, the invention provides a Gentiana nubigena endophyte applicable to biological control of plant diseases and its fermentation process. The strain involved in the invention is Bacillus pumilus LD-b1, which is preserved in the General microbiological center of China Committee for Culture Collection of Microorganisms on May 14, 2012, and has a preservation number of CGMCC No.6112. Mixed strain agar plate punching method experiments show that the strain LD-b1 can inhibit the growth of a plurality of plant disease fungi. LD-b1 can substantially inhibit Valsa mali from eroding apple fruits. In greenhouse pot experiments, the LD-b1 can achieve a cucumber Mycosphaerella arachidicola control effect of 81.2%. The fermentation process consists of: culturing LD-b1 in a seed tank for 24h to a logarithmic growth phase, inoculating 5% of the LD-b1 into a production tank according to an inoculation amount, controlling the initial pH at 7.5 and the fermentation temperature at 30DEG C, maintaining dissolved oxygen over 5%, and performing fed-batch fermentation for 68h, thus obtaining a bacterial amount over 10<10>cfu / mL. With the advantages of fast growth and wide antibacterial spectrum, the strain LD-b1 has good application prospects in biological control of plant diseases.

The invention discloses a cultivation method of a moss and desert algae composite crust. The cultivation method comprises the first step of collecting in summer a superior kind of moss in a natural habitat of an area to be restored; the second step of returning activities of the moss; the third step of using distilled water to wash moss crust the activities of which are returned and obtaining moss gametophyte; the fourth step of putting the gametophyte into a solid culture medium to be subjected to cultivation after the gametophyte is subjected to sterilization and obtaining moss protonema; the fifth step of picking the moss protonema and conducting static liquid cultivation to obtain differentiated gametophyte, and putting the gametophyte into a fluid culture medium to conduct aerobic cultivation; the sixth step of conducting aerobic cultivation on the desert algae through the fluid culture medium till a logarithmic growth phase, and obtaining algae thick liquid after removing supernatant; the seventh step of mixing the moss gametophyte with the desert algae thick liquid and afterwards inoculating the moss gametophyte and the desert algae thick liquid to the surface of desertification soil, and cultivating the moss and desert algae composite crust. The cultivation method of the moss and desert algae composite crust is easy to carry out and convenient to operate, evolvement process of biological soil crust in a desert area is accelerated, and fast treatment of desertification soil in arid and semi-arid lands is realized.

The invention discloses a method and a device for enriching anaerobic ammonium oxidizing bacteria based on modified basalt fiber filler, and belongs to the technical field of sewage biological treatment. The method is characterized by comprising the following steps: S1, starting a system, mixing nitrified sludge with anaerobic ammonium oxidized sludge, then adding the mixed sludge into a reactor filled with modified basalt fibers, and mixing the sludge thoroughly; S2, in an initial stage of culturing, sending matrix raw water into the reactor; at the same time, turning on circulating water forcircular flow; and S3, in a logarithmic growth phase, controlling the water inlet speed of the raw water matrix for continuous rapid enrichment culturing of the anaerobic ammonium oxidizing bacteria.By adopting the method for enriching the anaerobic ammonium oxidizing bacteria provided by the invention, the generation cycle of the anaerobic ammonium oxidizing bacteria can be effectively shortened, high-activity proliferation in a short time can be realized, effective enrichment culturing of the anaerobic ammonium oxidizing bacteria can be implemented, and a foundation is laid for the engineering application of the novel biological denitrification technology.

The present invention provides a vaccine for the bacterial cold-water disease in fish comprising inactivated cells of Flavobacterium psychrophilium in the logarithmic growth phase or components thereo

The invention discloses a construction method of a tilapia brain cell line. The method comprises the following steps: disinfecting fresh and live tilapia, taking brain tissue, cutting the tilapia intominced blocks, treating the minced blocks with collagenase, and adding trypsin; performing full suspension with a culture solution, and performing primary culture; when the bottom of a bottle is fullof cells, performing digestion with pancreatin-EDTA, and performing inoculation for secondary culture; and after 60 generations of secondary culture, adding colchicine in the logarithmic growth phasefor treatment, and performing karyotype analysis. The preparation method of the tilapia brain cell line, disclosed by the invention, is simple and convenient; and the tilapia brain cell line preparedby the method can perform secondary culture for a long time, is very sensitive to hemorrhagic disease viruses of tilapia, and can be widely applied to experiments.

The invention discloses a microbial strain for treatment of heavy metal contaminated soil, a screening method and application thereof. The screened microbial strain is Bacillus subtilis, and the preservation number is CCTCC NO:M 2017832. The microbial strain is inoculated into a medium for culture to a logarithmic growth period so as to obtain a bacterial liquid; and adding the bacterial liquid into the heavy metal contaminated soil, and the substances are mixed evenly to complete treatment of the heavy metal contaminated soil; or subjecting the bacterial liquid to vacuum freeze drying, then adding the treated bacterial liquid into soil, and mixing the substances evenly to complete treatment of the heavy metal contaminated soil; and immobilizing cadmium and chromium in the contaminated soil by passivation to reduce the bio-availability of cadmium and chromium and the absorption and utilization of cadmium and chromium by plants, thus reaching the purpose of remediating contaminated soil.

The invention discloses a method based on mixotroph microalgae oil accumulation, and belongs to the technical field of biodiesel. The method comprises the steps that a BG-11 basal culture medium adopting glucose as a carbon source is used for cultivating single algae, and algae cells are collected when the single algae grows to the rear logarithmic growth period; waste fermented liquid is dilutedto be adopted as the basal culture medium for single algae, and then, MgSO4 7H2O is added into the basal culture medium; the PH value is regulated to 6.8-7.1, and the culture medium is prepared; the prepared culture medium is subjected to high-pressure and high-temperature sterilization, oil-producing single algae is inoculated, the algae cell concentration is 0.9-1 g / L, then, absolute ethyl alcohol is added for dissolving a melatonin mother solution, the final concentration of melatonin in the culture medium is 10<-1>-10<-4> mol / L, and the algae solution is placed into strong light to be cultured; microalgae cultured to the stable stage is enriched, oil is extracted, and biodiesel is prepared. The method is simple and easy to implement, the production cost can be greatly lowered, the oilyield is remarkably increased, and therefore the biodiesel production efficiency of microalgae is greatly improved.

The invention discloses an adsorption separation coupling fermentation process with high nisin yield. A certain amount of resin is added in the logarithmic growth phase to adsorb the nisinin fermentation on the resin, thus on the one hand reducing concentration of nisin in the fermentation liquid to relieve the inhibitory effect on cell growth and product synthesis and on the other hand effectively improving the fermentation concentration of nisin. The nisin concentration in the invention reaches above 10000U / mL, which is significantly higher than the concentration of nisin in a general fermentation method. In addition, Lactococcus lactis CQ0422 with the preservation number of CGMCC NO.8090 is used as a fermentation strain, which has the yield of synthesized nisin at least 4.5 times of that of the general Lactococcus lactis, so as to play an important role in improving the nisin yield. The invention has the advantages of simple process, low production cost, concentration and high yield of nisin, etc.

The invention discloses a method for forecasting rhizoma atractylodis growth by a four-parameter logistic equation, which relates to the field of agricultural engineering. The regression analysis is executed by biomass (Y) of measured growth indexes and data of measured growth time (X) for computing reasonable regression coefficients: a, Y0, X0 and b; a four-parameter logistic regression equationis established as follows: Y=Y0+a / (1+(x / x0)), wherein in the four-parameter logistic regression equation, Y is the measured biomass, Y0 is the initial biomass of entering a logarithmic growth phase, a is the upper limit of the biomass along with time, X0 is the number of days when reaching half of the logarithmic growth phase, X is the measured growth time and b is a coefficient, i.e. a constant. The method can be used for forecasting the growth of all kinds of rhizoma atractylodis and providing guidance for fertilizing all kinds of rhizoma atractylodis, selecting picking and harvesting time and evaluating the yield.

The present invention provides a biological activity detection method for VEGF targeted therapy drugs. The biological activity detection method comprises: taking HUVEC cells being in a logarithmic growth phase, adjusting to achieve an appropriate cell density, plating, and culturing to make cells be adhered on the plate; carrying out series gradient dilution on a reference substance and a sample, sequentially adding to a culture plate with paved cells, and continuously incubating for a certain time; and carrying out a coloration reaction on the cell culture plate by using a detection system for detecting the amount of living cells or dead cells, and obtaining the biological activity of the sample according to the coloration reaction results. According to the present invention, the requirements on the specificity, the accuracy, the precision (including repeatability, day difference, personnel operating error, and the like) and other verifications can be met, and the method can be effectively applied for screening and quality control of VEGF targeted therapy drugs.