Abstract: The present disclosure discloses an Escherichia coli-based genetically-modified recombinant strain, a construction method therefor and use thereof. A mutant gene obtained by subjecting a wild-type deoB gene (ORF sequence is shown in a sequence 3902352-3903575 in GenBank accession No. CP032667.1) and a wild-type rhtA gene promoter sequence PrhtA (shown in a sequence 850520-850871 in GenBank accession No. AP009048.1) of an E. coli K12 strain and a derivative strain thereof (such as MG1655 and W3110) to site-directed mutagenesis, and a recombinant strain obtained therefrom can be used for the production of L-threonine, and compared with an unmutated wild-type strain, the obtained strain can produce L-threonine with a higher concentration and has good strain stability, and also has lower production cost as an L-threonine production strain.

Abstract: Provided is a method for introducing a point mutation to a BBD29_04920 gene coding sequence in Corynebacterium or improving the expression thereof. The point mutation causes a mutation to the base at position 1560 in the BBD29_04920 gene sequence from cytosine (C) to adenine (A) such that asparagine at position 520 of a coded corresponding amino acid sequence is substituted by lysine. The method can increase fermentation yield of glutamic acid in a strain with the mutation. Also provided are the bacterium generating L-glutamic acid, a nucleic acid and protein comprising the mutation, a recombinant vector and recombinant strain comprising the nucleic acid, and use of these biomaterials in the regulation of the production of L-glutamic acid of a microorganism.

Abstract: Provided are a recombinant strain with modified gene BBD29_14900, and a method for constructing the same and use thereof, with the production of L-glutamic acid as a specific application. Further provided is a method for introducing a point mutation into the BBD29_14900 gene coding sequence in Corynebacterium or improving the expression thereof. The method can cause a bacterial strain with the mutation to increase the fermentation yield of glutamic acid. The point mutation involves a mutation of the base at position 1114 in the sequence of the BBD29_14900 gene from guanine (G) to adenine (A), and thus a substitution of aspartic acid at position 372 in the coded corresponding amino acid sequence with asparagine.

Abstract: Disclosed are strain having enhanced L-glutamic acid production capacity, and method for constructing the same and use thereof. A nucleotide sequence is provided by introducing a point mutation to a wild-type BBD29-00405 gene in Corynebacterium glutamicum so that the base at position 597 of SEQ ID NO: 1 is mutated from guanine (G) into adenine (A). Also provided is a recombinant strain obtained by introducing the polynucleotide sequence into L-glutamic acid-producing Corynebacterium glutamicum, the recombinant strain comprising a BBD29-00405 gene containing a point mutation. Compared with an unmodified strain, the resulting strain facilitates production of L-glutamic acid at a higher concentration.

Abstract: A recombinant strain with modified gene BBD29_11265 and a method for constructing the same are provided. The recombinant strain is a bacterium that generates L-glutamic acid, and has an improved expression of a polynucleotide encoding an amino acid sequence of SEQ ID NO: 3 or a homologous sequence thereof; the improved expression can be having a point mutation in, and an enhanced expression of the polynucleotide encoding an amino acid sequence of SEQ ID NO: 3 or a homologous sequence thereof. A genetically engineered bacterium in which the base at position 70 in the BBD29_112665 gene sequence is mutated to adenine from guanine, causing alanine at position 24 in the coded corresponding amino acid sequence to be substituted with threonine, and an engineered bacterium overexpressing the BBD29_112665 gene or BBD29_11265G70A gene are constructed in the present invention, facilitating an increase in the production and conversion rate of L-glutamic acid.

Abstract: Taking Corynebacterium glutamicum YP97158 as the starting bacterium, introducing site-directed mutation and/or expression enhancement in the coding region of its NCgl1089 gene, the coding region of NCgl0761 gene, and/or the coding region of ptsS gene, the obtained mutant gene and the recombination comprising said gene has high-efficiency L-amino acids production capacity, which greatly increases the output of L-amino acids, and the strain has good stability, which reduces the production cost as an L-amino acids production strain.

Abstract: A bacterium for producing L-amino acid has improved expression of a polynucleotide encoding a protein represented by SEQ ID NO:3 and improved expression of a polynucleotide encoding a protein represented by SEQ ID NO:31, and/or has mutations in bases at positions ?45 bp and ?47 bp of a promotor region represented by SEQ ID NO:57. A polynucleotide, encodes proteins and can be included in a recombinant vector, which can be included in a recombinant strain. These are useful in a method for producing L-amino acid. The polynucleotide encodes a protein which is represented by SEQ ID NO:3 and has arginine at position 334 substituted by a terminator or encodes a protein which is represented by SEQ ID NO:31 and has tyrosine at position 592 substituted by phenylalanine, or is formed by mutations in bases at positions ?45 bp and ?47 bp of a promotor region represented by SEQ ID NO:57.

Abstract: An Escherichia coli-based kdtA-gene-modified recombinant strain, a construction method therefor and use thereof are provided. A mutant gene obtained by subjecting a wild-type kdtA gene (ORF sequence is shown in a sequence 73556-74833 in GenBank accession No. CP032667.1), a wild-type spoT gene (ORF sequence is shown in a sequence 3815907-3818015 in GenBank accession No. AP009048.1) and a wild-type yebN gene (ORF sequence is shown in a sequence 1907402-1907968 in GenBank accession No. AP009048.1) of an E. coli K12 strain and a derivative strain thereof (such as MG1655 and W3110) to site-directed mutagenesis, and a recombinant strain obtained therefrom can be used for the production of L-threonine. Compared with an unmutated wild-type strain, the obtained strain can produce L-threonine with a higher concentration and has good strain stability, and also has lower production cost as an L-threonine production strain.

Abstract: The present disclosure discloses an Escherichia coli-based genetically-modified recombinant strain, a construction method therefor and use thereof. A mutant gene obtained by subjecting a wild-type deoB gene (ORF sequence is shown in a sequence 3902352-3903575 in GenBank accession No. CP032667.1) and a wild-type rhtA gene promoter sequence PrhtA (shown in a sequence 850520-850871 in GenBank accession No. AP009048.1) of an E. coli K12 strain and a derivative strain thereof (such as MG1655 and W3110) to site-directed mutagenesis, and a recombinant strain obtained therefrom can be used for the production of L-threonine, and compared with an unmutated wild-type strain, the obtained strain can produce L-threonine with a higher concentration and has good strain stability, and also has lower production cost as an L-threonine production strain.

Abstract: Provided are a fluorescent dye and a preparation process and use thereof. The fluorescent dye is able to emit a long wavelength, is sensitive and specific to viscosity, and is used for a wide range of purposes, such as viscosity testing, fluorescent labeling, quantification or detection of proteins, enzymes or nucleic acids. In addition, it can be used as a fluorescent-activated probe.

Abstract: Provided are a fluorescent probe and a preparation process and the use thereof. The fluorescent probe is sensitive and specific to viscosity, and can be used for specific fluorescent labeling of proteins, and can also be used for quantification, detection or kinetic studies of proteins, and the imaging of cells, tissues and living bodies.

Abstract: Provided are a fluorescent dye and a preparation process and use thereof. The fluorescent dye is able to emit a long wavelength, is sensitive and specific to viscosity, and is used for a wide range of purposes, such as viscosity testing, fluorescent labeling, quantification or detection of proteins, enzymes or nucleic acids. In addition, it can be used as a fluorescent-activated probe.

Abstract: Provided are a fluorescent probe and a preparation process and the use thereof. The fluorescent probe is sensitive and specific to viscosity, and can be used for specific fluorescent labeling of proteins, and can also be used for quantification, detection or kinetic studies of proteins, and the imaging of cells, tissues and living bodies.

Abstract: A method for producing L-lysine by fermentation comprises the steps of modifying an aconitase gene and/or regulatory element thereof in a chromosome of a bacterium so that the activity and/or the expression amount of the aconitase of the bacterium are reduced but not eliminated; and producing L-lysine by the fermentation of the modified bacterium. In addition, also provided are methods and uses derived from the method as well as bacteria used in these methods and uses.