35 results about "Low molecular weight dextran" patented technology

Disclosed are hybrid genes of glucanase and dextransucrase, recombinant vectors comprising said hybrid genes, microorganisms which are transformed with said recombinant vectors, hybrid enzymes which are expressed from said hybrid genes, and processes for preparing isomalto-oligosaccharides or dextran using said microorganisms or enzymes. Expensive isomalto-oligosaccharides and low molecular weight dextran for clinical use can be produced simply and effectively from cheap substrate-sucrose, using a single bacterial strain or enzyme.

Methods, and related products and compositions, of increasing the stability of a Bayer process liquor are described. A method of increasing the stability of a Bayer process liquor includes contacting the Bayer process liquor with a ppm quantity of a low molecular weight dextran. Also described are methods, and related products and compositions, for controlling the precipitation of aluminum-containing compounds from a Bayer process liquor.

The invention provides a cord blood hematopoietic stem cell preservation solution and a preparation method thereof, belonging to the technical field of cell preservation. The raw materials of the preservation solution include: low molecular weight dextran, dimethyl sulfoxide, DMEM medium, glycerol, folic acid, mannose Polysaccharide and phosphatidylserine are mixed with raw materials to obtain a preservation solution, and then mixed with hematopoietic stem cells after two stages of variable temperature pretreatment to preserve hematopoietic stem cells. The prepared preservation solution has a long preservation time, the preserved stem cells have less cell damage after resuscitation, and the survival rate of the stem cells is high, and the preparation and preservation methods are simple and inexpensive.

The invention discloses a method for preparing medium-low molecular weight dextran by using a biological method. The method comprises the following steps: adding a leuconostoc mesenteroides seed solution in a fermentation medium containing sucrose for carrying out fermentation culture; then adding a penicillium cyclopium seed solution or fermentation broth supernate of the penicillium cyclopium for continuously fermenting and culturing; and separating dextran from the fermentation broth to obtain the medium-low molecular weight dextran. The invention further discloses the prepared dextran and application thereof. The invention provides a method for directly obtaining the medium-low molecular weight dextran by using the biological method in a mode of coupling fermentation of double microorganisms. The medium-low molecular weight dextran is synthesized by directionally regulating and controlling through the biological method, so that the generated dextran degrades to form dextran which tends to be required by clinical application. Meanwhile, according to the method disclosed by the invention, ethanol precipitation can be directly carried out, and thus redundant, time-consuming and noble gradual dividing precipitation is omitted, the yield of the dextran is increased, and the use amount and the consumption of ethanol are reduced.

The present invention provides a method for preparing a cross-linked dextran gel resistant to hydrolysis by α-glucosidase. The low-molecular-weight dextran is used as the starting skeleton, and an activator containing an epoxy group is used to activate it to make It has a plurality of epoxy groups, activated low-molecular-weight dextran; the epoxy-containing activator is 1,4-butanediol diglycidyl ether, ethylene glycol diglycidyl ether or epoxy A kind of chloropropane; using activated low molecular weight dextran as a biological cross-linking intermediate to mix with high molecular weight dextran and carry out a cross-linking reaction to form a hydrogel, and homogenize to form uniform gel particles; adding N -Acetyl-D-glucosamine, D-glucosamine, and cellobiose functional monomers. In the gel prepared by the method, the catalytic efficiency of α-glucosidase is reduced by more than 50% in the experiment of in vitro dextran hydrolysis.

The invention provides a protection solution for preparing decellularized corneas. The protection solution is a PBS or HBSS buffer solution, wherein 5-12 g / L of hyaluronic acid, 5-20 g / L of chondroitin sulfate, and 3-10 g / L of low molecular weight dextran are added in the PBS or HBSS buffer solution. According to the protection solution, protective ingredients are added in the basic buffer solution, the prepared protection solution can maintain the colloid osmotic pressure of a preparing solution of decellularized corneas through selection of components and a proportion, and compared with a traditional preparing solution for decellularized corneas, cornea transparency decreasing caused by excessive swelling and missing of extracellular matrix ingredients such as collagen in the decellularization treatment process in a later stage can be remarkably relieved; besides, antibiotic ingredients such as tobramycin are added, breeding of bacteria such as pseudomonas aeruginosa, klebsiella biofilm, enterobacter and proteus which are likely to infect corneas is suppressed, and the contamination probability in the treatment process is avoided.

The invention discloses a preparation method for dextranase and application of the dextranase in preparation of low molecular dextran. The invention is characterized in that a producing bacterial strain for the dextranase is Penicillium aculeatum F1008 separated from soil and the bacterial strain is preserved in China General Microbiological Culture Collection Center with an accession number of CGMCC No. 8135. According to the invention, the dextranase with high enzyme activity is successfully prepared through fermentation culture of Penicillium aculeatum F1008; the dextranase has catalysis temperature of 25 to 35 DEG C, a catalysis pH value of 5.0 to 6.0 and average enzyme activity of higher than 600 U / mL, gives preference to reaction with a high-molecular-weight substrate in a multi-substrate solution and is especially applicable to preparation of low-molecular-weight dextran; low molecular dextran varieties prepared through catalysis of the Penicillium aculeatum F1008 dextranase comprise micromolecular dextran with weight average molecular weight of 10000 Da, 6000 to 8000 Da and 3000 to 5000 Da. The dextranase has the advantages of mild catalytic reaction condition, good substrate specificity, low energy consumption and capacity of achieving the objects consisting of yield increase, low carbon and low cost in production of micromolecular dextran.

The invention discloses a preparation method of an adenosine triphosphate coenzyme insulin freeze-dried powder injection, comprising the following steps of: adjusting injection water with diluted hydrochloric acid until the pH value is 2.5-3.5, adding insulin and uniformly mixing to obtain a solution I; adding L-arginine and disodium ethylene diamine tetraacetate in the injection water, uniformly stirring, adding carbon and stirring; after removing carbon, adding adenosine disodium triphosphate and uniformly stirring to obtain a solution II; adding calcium gluconate, low molecular weight dextran and cysteine hydrochloride in the injection water, adding carbon and removing the carbon and uniformly stirring to obtain a solution III; mixing three solutions, uniformly stirring, adjusting the pH value to be 5.7-6.2 with a 2-4 percent NaOH solution, adding coenzyme A and supplementing the balance of injection water; and sterilizing, measuring the content, subpackaging and freezing dry. The adenosine triphosphate coenzyme insulin freeze-dried powder injection prepared by the method has the advantages of favorable redissolution, clearness and quality stability of products and is saturated in appearance.

The invention discloses a preparation method of iron-dextrin. The preparation method comprises the following steps: preparing low molecular weight dextran through bi-enzyme (dextransucrase-dextranase) synergy, and then oxidizing dextran by taking sodium hypochlorite mixed liquor as an oxidizing agent, so as to obtain an oxidation-type dextran; simultaneously titrating and complexing with weak base and acid-base to prepare iron-dextrin and curing iron-dextrin under the conditions of high temperature and high pH value, so as to obtain cured iron-dextrin; filtering unreacted dextran and micromolecule iron-dextrin and ions therein with biological membranes with different molecular weights, so as to obtain purified iron-dextrin. The iron-dextrin prepared by the invention is uniform in distribution of the molecular weight, high in stability and less in content of impurities. Various indexes of iron-dextrin synthesized by the method conform to the requirements of Chinese pharmacopoeia, and the solubility of iron-dextrin is very good.

The invention relates to clinical-grade cellular protection liquid as well as a preparation method and application thereof. The clinical-grade cellular protection liquid contains a human serum albumin injection, a low-molecular-weight dextran and amino acid injection and an isotonic sodium chloride injection. The preparation method comprises the step of uniformly mixing the human serum albumin injection, the low-molecular-weight dextran and amino acid injection and the isotonic sodium chloride injection. Compared with the prior art, the preparation method has the advantages that a proper amount of the human serum albumin injection and a proper amount of the dextran and amino acid injection are creatively added into the isotonic sodium chloride injection, so that nutrients can be provided for cells, meanwhile, acid-base imbalance caused by cellular metabolism can be regulated, cellular damage caused due to acidosis can be relieved, the cell survival rate can be greatly increased, the cell viability can be maintained, the cell survival time is relatively long, the cells can be directly applied to clinical application, and the application is relatively safe and convenient; and the preparation method is simple, convenient and rapid.