• Title/Summary/Keyword: Cloning and Expression

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Food-Grade Expression and Secretion Systems in Lactococcus

  • Jeong, Do-Won;Hwang, Eun-Sun;Lee, Hyong-Joo
    • Food Science and Biotechnology
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    • v.15 no.4
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    • pp.485-493
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    • 2006

  • Lactococcus species are noninvasive and nonpathogenic microorganisms that are widely used in industrial food fermentation and as well-known probiotics. They have been modified by traditional methods and genetic engineering to produce useful food-grade materials. The application of genetically modified lactococci in the food industry requires their genetic elements to be safe and stable from integration with endogenous food microorganisms. In addition, selection for antibiotic-resistance genes should be avoided. Several expression and secretion signals have been developed for the production and secretion of useful proteins in lactococci. Food-grade systems composed of genetic elements from lactic acid bacteria have been developed. Recent developments in this area have focused on food-grade selection markers, stabilization, and integration strategies, as well as approaches for controlled gene expression and secretion of foreign proteins. This paper reviews the expression and secretion signals available in lactococci and the development of food-grade markers, food-grade cloning vectors, and integrative food-grade systems.

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Cloning of Bacillus amyloliquefaciens amylase gene using YRp7 as a vector II. Expression of cloned amylase gene in Saccharomyces cerevisiae (YRp7 vector를 이용한 Bacillus amyloliquefaciens amylase gene의 cloning I I. Saccharomyces cerevisiae에서 발현)

  • 서정훈;김영호;전도연;배영석;홍순덕;이종태
    • Microbiology and Biotechnology Letters
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    • v.14 no.3
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    • pp.213-218
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    • 1986

  • Hybrid plasmid pEA24, shuttle vector YRp7 carrying amylase gene of Bacillus amyloliquefaciens, was transformed to yeast Saccharomyces cerevisiae, and the expression of B. amyloliquefaciens amylase gene in yeast was investigated. The frequency of transformation to S. cerevisiae DBY747 with YRp7 was increased by treatment of 40% polyethylene glycol (MW 4, 000), PH 7.0, at 3$0^{\circ}C$, and by regeneration used 2% top agar. The amount of cellular amylase activity produced by S. cerevisiae containing pEA24 was 2% of that secreted from B. amyloliquefaciens, but in case of S. cerevisiae transformant, the amylase secreted was not detected. A comparison of genetic stability of pEA24 and YRp7 plasmids in yeast was carried out by cultivation of transformants in tryptophan-supplement-medium. The pEA24 plasmid was more unstable than YRp7 in S. cerevisiae. The size of pEA24 extracted from S. cerevisiae transformants was found to be identical with that from E. coli transformants by agarose gel electrophoresis.

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Cloning Livestock from Cultured Cells Creates New Opportunities for Agriculture

  • Wells, D.N.
    • Proceedings of the Korean Society of Developmental Biology Conference
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    • 2003.10a
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    • pp.29-48
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    • 2003

  • It is remarkable that nuclear transfer using differentiated donor cells can produce physiologically normal cloned animals, but the process is inefficient and highly prone to epigenetic errors. Aberrant patterns of gene expression in clones contribute to the cumulative losses and abnormal phenotypes observed throughout development. Any long lasting effects from cloning, as revealed in some mouse studies, need to be comprehensively evaluated in cloned livestock. These issues raise animal welfare concerns that currently limit the acceptability and applicability of the technology. It is expected that improved reprogramming of the donor genome will increase cloning efficiencies realising a wide range of new agricultural and medical opportunities. Efficient cloning potentially enables rapid dissemination of elite genotypes from nucleus herds to commercial producers. Initial commercialization will, however, focus on producing small numbers of high value animals for natural breeding especially clones of progeny-tested sires, The continual advances in animal genomics towards the identification of genes that influence livestock production traits and human health increase the ability to genetically modify animals to enhance agricultural efficiency and produce superior quality food and biomedical products for niche markets. The potential opportunities in animal agriculture are more challenging than those in biomedicine as they require greater biological efficiency at reduced cost to be economically viable and because of the more difficult consumer acceptance issues. Nevertheless, cloning and transgenesis are being used together to increase the genetic merit of livestock; however, the integration of this technology into farming systems remains some distance in the future.

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Cloning Livestock from Cultured Cells Creates New Opportunities for Agriculture

  • Wells, D.N.
    • Proceedings of the Korean Society of Embryo Transfer Conference
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    • 2003.10a
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    • pp.29-48
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    • 2003

  • It is remarkable that nuclear transfer using differentiated donor cells can produce physiologically normal cloned animals, but the process is inefficient and highly prone to epigenetic errors. Aberrant patterns of gene expression in clones contribute to the cumulative losses and abnormal phenotypes observed throughout development. Any long lasting effects from cloning, as revealed in some mouse studies, need to be comprehensively evaluated in cloned livestock. These issues raise animal welfare concerns that currently limit the acceptability and applicability of the technology. It is expected that improved reprogramming of the donor genome will increase cloning efficiencies realising a wide range of new agricultural and medical opportunities. Efficient cloning potentially enables rapid dissemination of elite genotypes from nucleus herds to commercial producers. Initial commercialisation will, however, focus on producing small numbers of high value animals for natural breeding especially clones of progeny-tested sires. The continual advances in animal genomics towards the identification of genes that influence livestock production traits and human health increase the ability to genetically modify animals to enhance agricultural efficiency and produce superior quality food and biomedical products for niche markets. The potential opportunities inanimal agriculture are more challenging than those in biomedicine as they require greater biological efficiency at reduced cost to be economically viable and because of the more difficult consumer acceptance issues. Nevertheless, cloning and transgenesis are being used together to increase the genetic merit of livestock; however, the integration of this technology into farming systems remains some distance in the future.

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Cloning and Expression of the dapD Gene from Brevibacterium lactofermentum in E. coli (Brevibacterium lactofermentum의 dapD 유전자의 Cloning 및 E. coli에서의 발현)

  • 김옥미;박선희;박혜경;이승언;하대중;이갑랑
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.30 no.5
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    • pp.802-805
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    • 2001

  • The dapD gene of Brevibacterium lactofermentum encoding tetrahydrodipicolinate N-succinyl transferase, one of the enzymes involved in lysine biosynthesis, was cloned by complementation of Escherichia coli dapD mutnat. The recombinant plasmid pLS1 was found to contain a 3.6 kb DNA fragment. Southern hybridization analysis confirmed that the cloned DNA fragment originated from B. lactofermentum. The data of L-lysine production showed that the B. lactofermentum dapD gene was expressed in E. coli.

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