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Streptomyces Host-Vector Systems
Published in Yoshikatsu Murooka, Tadayuki Imanaka, Recombinant Microbes for Industrial and Agricultural Applications, 2020
The plasmid SLP1.2, which has a size estimated at 14.5 kb, was isolated from S. lividans 66 after mating with S. coelicolor A3(2) and has an intermediate-copy-number of four to five per chromosome. SLP1.2 comes from a chromosomal DNA sequence of S. coelicolor that loops out from the chromosome and is transferred by conjugation to S. lividans [11]. The plasmid was used in S. lividans to clone genes coding for the antibiotic-modifying enzymes, such as an aminoglycoside phosphotransferase (aph) and a neomycin acetyltransferase (aac) from S. fradiae ATCC10745. pIJ61 was constructed from SLP1.2 by the addition of the aph gene of S. fradiae and the thiostrepton-resistance gene from S. azur eus ATCC 14921, and deletion of two segments of nonessential SLP1.2 [12]. Single sites for BamHl, Pst I, and Xba I in the aph gene in pIJ61 allows the possibility of insertional inactivation.
Application of Microbial Enzymes in Industry and Antibiotic Production
Published in Pankaj Bhatt, Industrial Applications of Microbial Enzymes, 2023
Rishendra Kumar, Lokesh Tripathi, Pankaj Bhatt
Antibiotic production has increased due to the increasing number of drug-resistant pathogens. Therefore, there are new startup companies that have improved the model for antibiotic production and marketing (Reed et al., 2002). Semi-synthetic aminoglycoside antibiotics include amikacin, netilmicin, and isepamicin, which were developed to shield against resistance organisms (Miller et al., 1976; Leggett, 2015) (Van Bambeke et al., 2017). Neomycin was produced by immobilized Streptomyces fradiae (Srinivasulu et al., 2003), used as antibacterial agents. Most of the penicillin is converted into effective antibiotics, like ampicillin, amoxicillin, and cephalexin, through chemical synthesis. These converted antibiotics have improved the efficacy or pharmacokinetic properties.
Agricultural biotechnology
Published in Firdos Alam Khan, Biotechnology Fundamentals, 2018
In order to select only cells that have actually incorporated the new genes, the genes coding for the desired trait are fused to a gene that allows selection of transformed cells, so-called marker genes. The expression of the marker gene enables the transgenic cells to grow in the presence of a selective agent, usually an antibiotic or a herbicide, while cells without the marker gene die. One of the most commonly used markers is the bacterial aminoglycoside-3′ phosphotransferase gene (APH(3′)II), also referred to as neomycin phosphotransferase II (NPTII). This gene codes for an enzyme that inactivates the antibiotics kanamycin, neomycin, and G418 through phosphorylation. In addition to NPTII, a number of other antibiotic resistance genes have been used as selective markers, such as hygromycin phosphotransferase gene conferring resistance to hygromycin. Another group of selective markers is herbicide tolerance genes. Herbicide tolerance has been obtained through the incorporation and expression of a gene that either detoxifies the herbicide in a similar manner as the antibiotic resistance gene products or expresses a product that acts like the herbicide target but is not affected by the herbicide. Herbicide tolerance may not only serve as a trait useful for selection in the development of transgenic plants but also has some commercial interest. Transformation of plant protoplasts, cells, and tissues are usually only useful if they can be regenerated into whole plants. The rate of regeneration varies greatly not only among different species but also between cultivars of the same species. Besides the ability to introduce a gene into the genome of a plant species, regeneration of intact, fertile plants out of transformed cells or tissues is the most limiting step in developing transgenic plants (Figure 6.9).
Neomycin removal using the white rot fungus Trametes versicolor
Published in Journal of Environmental Science and Health, Part A, 2022
Åke Stenholm, Mikael Hedeland, Curt E. Pettersson
Aminoglycosides which are a class of antibiotics to which neomycin belong, are used in human applications and in veterinary medicine.[3–5] They consist of aminated sugars joined in glycosidic linkages to a dibasic cyclitol.