47 results about "Deficient mutant" patented technology

The invention relates to an application of a Zea mays grain transcription factor in the aspect of regulation and control of alcohal-soluble proteins. The factor comprises a base sequence shown in SEQ ID NO: 1. The protein ZmbZIP22 encoded by the sequence can be directly bonded to a 27kDa gamma-gliadin promoter and activate the 27kDa gamma-gliadin promoter. Gene-deficient mutant plants are obtained through carrying out Zea mays immature-embryo conversion by taking a gene fragment, shown in SEQ ID NO: 2, of ZmbZIP22 as a guide RNA by using a CRISPR-Cas9 technology. Compared with wild type grains, transgenic mutants have Zea mays grains with irregular and relative-thin protein body shells, the content of alcohal-soluble proteins in mature grains is remarkably lowered, the content of essential amino acids such as lysine, which are deficient to the conventional Zea mays, in the mature grains is remarkably increased, and thus, the nutritional quality of Zea mays is improved.

The present invention relates to methods of producing a heterologous biological substance, comprising: (a) cultivating a mutant of a parent Aspergillus niger strain in a medium suitable for the production of the heterologous biological substance, wherein (i) the mutant strain comprises a first nucleotide sequence encoding the heterologous biological substance and one or more second nucleotide sequences comprising a modification of glaA and at least one of the genes selected from the group consisting of asa, amyA, amyB, prtT, and oah, and (ii) the mutant strain is deficient in the production of glucoamylase and at least one enzyme selected from the group consisting of acid stable alpha-amylase, neutral alpha-amylase A, and neutral alpha-amylase B, protease, and oxalic acid hydrolase compared to the parent Aspergillus niger strain when cultivated under identical conditions; and (b) recovering the heterologous biological substance from the cultivation medium. The present invention also relates to enzyme-deficient mutants of Aspergillus niger strains and methods for producing such mutants.

A method for preparing a sericin hydrogel, the method including: 1) weighing a cocoon of a fibroin-deficient mutant silkworm, Bombyx mori, extracting the cocoon by an aqueous solution of LiBr or LiCl, dialyzing an extracted solution to yield a sericin solution having a concentration of a non-degraded sericin of between 0.1 and 4 wt. %; and 2) concentrating the sericin solution to a concentration of between 1.5 and 10 wt. %, adding a crosslinking agent to the concentrated sericin solution at a ratio of between 2 and 500 μL of the crosslinking agent per each milliliter of the sericin solution, fully blending the crosslinking agent with the concentrated sericin solution, and keeping a resulting mixture at the temperature of between 4 and 45° C. for between 5 s and 36 hrs to yield a hydrogel.

It is possible to inactivate the early stage of lipid A synthesis of mucosal gram negative bacteria without compromising cell viability. In particular the lpxA gene in N. meningitidis was mutated and resulting lpxA knockout mutants were found to be completely lipopolysaccharide (LPS)-deficient. The major outer membrane proteins (OMPs) were detected in normal amounts. The finding provides important implications for understanding of structure and biogenesis of the outer membrane. On a practical level, the availability of LPS-deficient mutants of pathogenic mucosal bacteria such as N. meningitidis opens up new avenues to vaccine development. It enables easy isolation of endotoxin-free purified proteins, outer membranes or even whole-cell preparations for use in immunisation.

This invention provides a rice gene coding beta-keto co A synthetase, OsKCS1, which comprises 2186bp and 1560bp coding zones at the upstream of the start codon with promoter function, codes 519 amino acid, and contains typical FAE1 CUT1 RppA domain. The function-deficient mutant P1424 obtained by inserting T-DNA into rice OsKCS1 gene has short plants, occasionally curled leaves, and low fruiting rate. Further research shows that the wax at the surfaces of the mutant gas-generating organs is obviously reduced, and the draught resistance is seriously influenced. The expression of OsKCS1 gene in the mutant can recover its wild phenotype, thus can confirm the direction relationship between OsKCS1 gene and synthesis and growth of wax on rice surfaces. The identification of the gene is important to research on synthesis of wax on rice surfaces, and breeding of draught-resistant rice or other monocotyledon crops.

The invention discloses a method for improving microalgae growth rate and oil yield, and the method includes the following steps: 1), after inoculation of microalgae, the microalgae is cultured for 2-5 days by continuous illumination or cycled illumination in a certain light and dark conditions at 20-35 DEG C and in the conditions of 20-200 mu mol photon in m<-2>s<-1>; 2), the microalgae strain obtained by the step 1) is inoculated again, and then cultured; and 3), the microalgae strain is cultured by step 1) as a training cycle, and then cultured by step 2) as a next training cycle, and the microalgae strain with the growth rate and oil yield both increased can be obtained by the cycled training. According to the method, the growth rate and oil yield both of wild microalgae strains and microalgae gene deficient mutants are increased, and compared with the large-scale screening, the method is less in workload and high in efficiency, is a new strain selection method, and has broad application prospects in microalgae biofuel development.

As the richest source of astaxanthin, a natural antioxidant and coloring agent, the unicellular green alga, Haematococcus pluvialis, is being commercially exploited. A major constraint in the Haematococcus production system, however, is the thick, rigid cell walls associated with astaxanthin-rich cysts (or aplanospores). The thick walls prevent the extraction of cellular materials and consequently reduce the bioavailability of astaxanthin. Using a physical, chemical, or enzymatic method to disrupt the cell wall has proven to be very expensive and also introduce the risk of oxidation of astaxanthin by atmospheric oxygen The present invention provides a novel method for solving this problem by introducing two genetically modified Haematococcus pluvialis mutants. These two mutants, named as D 13-17 and N54-22, contain remarkably reduced amounts of cell wall materials, but retain the growth potential and ability to accumulate astaxanthin as high as the wild type strain. Organic solvent extraction efficiency assay has demonstrated that cellular astaxanthin can be more effectively and efficiently extracted from the cell wall-deficient mutants than from the wild type, suggesting that the mutants may provide better bioavailability of astaxanthin to humans and animals. The said mutants can be used for production of natural astaxanthin for human and animal consumption

The present invention provides transgenic mice deficient in urocortin. Urocortin null mutant mice are hypersensitive to stress and display heightened anxiety-like behaviors in the elevated plus maze and open field tests. These mice also demonstrate physiological alterations in auditory thresholds and distortion product otoacoustic emissions. These results indicate that urocortin plays a modulatory role in anxiety-related behaviors and in contributing to the establishment of auditory thresholds. Such urocortin deficient mutant mice can provide useful models in the study of anxiety pathology and hearing physiology at the biochemical and molecular levels.

The invention discloses polyketone compounds with antitumor activity, a preparation method therefor and an application of the polyketone compounds. The polyketone compounds (1 to 4) with structures represented by a formula (I) shown in the description are prepared through subjecting an enterocin gene cluster deficient mutant of Steptomyces qinglanensis 1772205 to fermentation and carrying out separation. Proven by in-vitro cytotoxin activity tests, the compounds (1 to 4) disclosed by the invention show inhibition activity of different degrees to tumor cells (HeLa and MCF-7), and particularly,the compound 1 shows a remarkable inhibiting effect on the tumor cells. Ideal candidate compounds are provided for the development of efficient antitumor drugs.

The invention belongs to the technical field of goat molecular marker preparation, and in particular relates to three goat MC1R deficient mutants and application thereof. Three deficient mutants are found in a goat MC1R and application thereof, two mutation sites F250V and G255D casing receptor defects both are located in a sixth transmembrane domain, and another mutation site C267W casing the receptor defects is located on a third external loop. The alpha-MSH ligand affinity of the three MC1R deficient mutants is lost, inducible and constitutive cAMP levels are significantly reduced, and inducible and constitutive p-ERK are significantly reduced. The goat MC1R deficient mutants can lead to the fact that a melanin production signal is blocked and the formation of black coat is affected. The molecular marker can be applied to assisted marker selection of goat wool color.

The present invention provides a method for manufacturing xylitol with high-yield and high-productivity by using a xylitol dehydrogenase-deficient mutant of xylitol producing microorganism. This goal is achieved through modification of the metabolic pathway of the xylitol producing microorganism, preferably a natural xylose-assimilating yeasts and fungi, by disrupting or inactivating the expression of desired genes.

The invention relates to an application of chlorella sorokiniana in a functional feed for improving the health condition of fishes. The Chlorella sorokiniana disclosed by the invention is a starch defect type mutant strain GT-1-SLM2, and a preservation number of the strain is CGMCC No.13862, and the strain is preserved in the China General Microbiological Culture Collection Center (CGMCC, an address is Institute of Microbiology, Chinese Academy of Sciences, No.3, Yard 1, West Beichen Road, Chaoyang District, Beijing). According to the invention, chlorella sorokiniana is used as starch-deficient mutant strain algae powder and is added into the fish feed, which can replace part of fish meal, can significantly improve the food intake, growth weight gain speed, oxidation resistance and immunity of fishes, the product can replace traditional antibiotics, and avoids the problems of ecological environment damage and food safety caused by large-scale application of antibiotics in the feed. Therefore, the invention provides a brand-new, green and safe immunopotentiator, a phagostimulant or an antioxidant.

The present invention relates to a nucleic acid molecule comprising the HpYPS1 gene encoding H. polymorpha yapsin1, a polypeptide encoded by the nucleic acid molecule, a H. polymorpha mutant strain having reduced yapsin activity by mutation of the HpYPS gene encoding H. polymorpha yapsin1, a recombinant H. polymorpha strain expressing a foreign protein produced by introducing a gene encoding the foreign protein into the H. polymorpha mutant strain, and a process for preparing a foreign protein comprising culturing the recombinant H. polymorpha strain under conditions to express the foreign protein and isolating the foreign protein from the culture.

The invention discloses a method for screening chlamydomonas reinhardtii cycle adjustment and control defect mutants. The method comprises specific steps that after a chlamydomonas reinhardtii mutantlibrary is established, cell cycle adjustment and control defect mutants are directly screened, wherein primary screening is performed according to the size of the diameter of a monoclone, and in re-screening, the concentration of cells is detected through a microplate reader OD434, so that the ratio of a 24h light absorption value to a 48h light absorption value is calculated, and chlamydomonas cell cycle adjustment and control defect mutants are screened and identified reference to a wild type reproduction ratio. According to the method disclosed by the invention, changes of the quantity ofchlamydomonas reinhardtii cells are detected through the microplate reader, so that the chlamydomonas cell cycle adjustment and control defect mutants are screened and identified. The method is simpleand convenient to operate and high in efficiency, cell cycle adjustment and control defect mutants can be quickly and stably obtained, and a base is established for subsequent experiments.

The invention relates to a natural mutant strain of mycobacterium tuberculosis PhoP of clinical isolates of mycobacterium tuberculosis in sputum samples of patients with tuberculosis in Xinjiang areasin the field of study on microbes. By collecting sputum samples of patients with tuberculosis in the department of infectious diseases in multiple Xinjiang areas, 438 clinical isolates are obtained,and by total DNA extraction, ordinary PCR (polymerase chain reaction) and fluorescence quantitative PCR, the natural mutant strain of PhoP in the clinical isolates is discovered.

The invention provides a construction method for producing fumaric acid based on pichia stipitis synthetic strain fermented xylose. The method comprises the following steps: using pichia stipitis having a natural xylose metabolic capability as a host; deleting genes PSfum1 and PSfum2 that encode fumarase in tricarboxylic acid cycle of pichia stipitis, to acquire fumarase deficient mutants; heterologously expressing a modified fumaric reduction synthesis module on the basis of the acquired mutants, using xylose to ferment yeast synthesis strains of fumaric acid; on the basis of the yeast synthesis strains, expressing translocator YMAE that is modified with codons and originated from Chestnut wine fission yeasts, to acquire pichia stipitis synthesis strains for producing fumaric acid by fermented xylose; efficiently fermenting the acquired strains in a fully synthesized fermentation culture medium to produce fumaric acid by fermentation of xylose; cultivating by fermentation for 3-4 days at a temperature of 30 degrees centigrade with a stirring speed of 150-200rpm. The content of fumaric acid is greater than 4g / L.

Some HBL and NHE enterotoxins are known to cause food-borne diseases in humans. Enterotoxin-deficient mutants of member strains of the Bacillus cereus group that do not produce HBL, HBLa1, HBLa2, or NHE enterotoxins are disclosed. Enterotoxin-deficient mutants are suitable for use as biocontrol agents. Methods for making the mutants and for using the mutants are described.

The present invention relates to methods of producing a heterologous biological substance, comprising: (a) cultivating a mutant of a parent Bacillus cell under conditions conducive for the production of the heterologous biological substance, wherein (i) the mutant cell comprises a first nucleic acid sequence directing synthesis of the heterologous biological substance and a second nucleic acid sequence comprising a modification of at least one of the genes cypX and yvmC, which are involved in the production of a red pigment, and (ii) the mutant cell is deficient in the production of the red pigment compared to the parent Bacillus cell when cultivated under the same conditions; and (b) recovering the heterologous biological substance from the cultivation medium. The present invention also relates to mutants of Bacillus cells and methods for producing the mutants.