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The three-domain system is a taxonomic classification system that groups all cellular life into three domains, namely Archaea, Bacteria and Eukarya, introduced by Carl Woese, Otto Kandler and Mark Wheelis in 1990. The key difference from earlier classifications such as the two-empire system and the five-kingdom classification is the splitting of Archaea from Bacteria as completely different organisms. It has been challenged by the two-domain system that divides organisms into Bacteria and Archaea only, as Eukaryotes are considered as a clade of Archaea.
In molecular biology and genetics, transformation is the genetic alteration of a cell resulting from the direct uptake and incorporation of exogenous genetic material from its surroundings through the cell membrane(s). For transformation to take place, the recipient bacterium must be in a state of competence, which might occur in nature as a time-limited response to environmental conditions such as starvation and cell density, and may also be induced in a laboratory.
Agrobacterium tumefaciens is the causal agent of crown gall disease in over 140 species of eudicots. It is a rod-shaped, Gram-negative soil bacterium. Symptoms are caused by the insertion of a small segment of DNA, from a plasmid into the plant cell, which is incorporated at a semi-random location into the plant genome. Plant genomes can be engineered by use of Agrobacterium for the delivery of sequences hosted in T-DNA binary vectors.
Agrobacterium is a genus of Gram-negative bacteria established by H. J. Conn that uses horizontal gene transfer to cause tumors in plants. Agrobacterium tumefaciens is the most commonly studied species in this genus. Agrobacterium is well known for its ability to transfer DNA between itself and plants, and for this reason it has become an important tool for genetic engineering.
The transfer DNA is the transferred DNA of the tumor-inducing (Ti) plasmid of some species of bacteria such as Agrobacterium tumefaciens and Agrobacterium rhizogenes . The T-DNA is transferred from bacterium into the host plant's nuclear DNA genome. The capability of this specialized tumor-inducing (Ti) plasmid is attributed to two essential regions required for DNA transfer to the host cell. The T-DNA is bordered by 25-base-pair repeats on each end. Transfer is initiated at the right border and terminated at the left border and requires the vir genes of the Ti plasmid.
In genetic engineering, a gene gun or biolistic particle delivery system is a device used to deliver exogenous DNA (transgenes), RNA, or protein to cells. By coating particles of a heavy metal with a gene of interest and firing these micro-projectiles into cells using mechanical force, an integration of desired genetic information can be introduced into desired cells. The technique involved with such micro-projectile delivery of DNA is often referred to as biolistics, short for "biological ballistics".
A tumour inducing (Ti) plasmid is a plasmid found in pathogenic species of Agrobacterium, including A. tumefaciens, A. rhizogenes, A. rubi and A. vitis.
Plasmodesmata are microscopic channels which traverse the cell walls of plant cells and some algal cells, enabling transport and communication between them. Plasmodesmata evolved independently in several lineages, and species that have these structures include members of the Charophyceae, Charales, Coleochaetales and Phaeophyceae, as well as all embryophytes, better known as land plants. Unlike animal cells, almost every plant cell is surrounded by a polysaccharide cell wall. Neighbouring plant cells are therefore separated by a pair of cell walls and the intervening middle lamella, forming an extracellular domain known as the apoplast. Although cell walls are permeable to small soluble proteins and other solutes, plasmodesmata enable direct, regulated, symplastic transport of substances between cells. There are two forms of plasmodesmata: primary plasmodesmata, which are formed during cell division, and secondary plasmodesmata, which can form between mature cells.
Gene delivery is the process of introducing foreign genetic material, such as DNA or RNA, into host cells. Gene delivery must reach the genome of the host cell to induce gene expression. Successful gene delivery requires the foreign gene delivery to remain stable within the host cell and can either integrate into the genome or replicate independently of it. This requires foreign DNA to be synthesized as part of a vector, which is designed to enter the desired host cell and deliver the transgene to that cell's genome. Vectors utilized as the method for gene delivery can be divided into two categories, recombinant viruses and synthetic vectors.
Jozef Stefaan "Jeff", Baron Schell was a Belgian molecular biologist.
Marc, Baron Van Montagu is a Belgian molecular biologist. He was full professor and director of the Laboratory of Genetics at the faculty of Sciences at Ghent University (Belgium) and scientific director of the genetics department of the Flanders Interuniversity Institute for Biotechnology (VIB). Together with Jozef Schell he founded the biotech company Plant Genetic Systems Inc. (Belgium) in 1982, of which he was scientific director and member of the board of directors. Van Montagu was also involved in founding the biotech company CropDesign, of which he was a board member from 1998 to 2004. He is president of the Public Research and Regulation Initiative (PRRI).
Plant Genetic Systems (PGS), since 2002 part of Bayer CropScience, is a biotech company located in Ghent, Belgium. The focus of its activities is the genetic engineering of plants. The company is best known for its work in the development of insect-resistant transgenic plants.
Plant transformation vectors are plasmids that have been specifically designed to facilitate the generation of transgenic plants. The most commonly used plant transformation vectors are T-DNA binary vectors and are often replicated in both E. coli, a common lab bacterium, and Agrobacterium tumefaciens, a plant-virulent bacterium used to insert the recombinant DNA into plants.
A transfer DNA (T-DNA) binary system is a pair of plasmids consisting of a T-DNA binary vector and a virhelper plasmid. The two plasmids are used together to produce genetically modified plants. They are artificial vectors that have been derived from the naturally occurring Ti plasmid found in bacterial species of the genus Agrobacterium, such as A. tumefaciens. The binary vector is a shuttle vector, so-called because it is able to replicate in multiple hosts.
Genetic engineering is the science of manipulating genetic material of an organism. The first artificial genetic modification accomplished using biotechnology was transgenesis, the process of transferring genes from one organism to another, first accomplished by Herbert Boyer and Stanley Cohen in 1973. It was the result of a series of advancements in techniques that allowed the direct modification of the genome. Important advances included the discovery of restriction enzymes and DNA ligases, the ability to design plasmids and technologies like polymerase chain reaction and sequencing. Transformation of the DNA into a host organism was accomplished with the invention of biolistics, Agrobacterium-mediated recombination and microinjection. The first genetically modified animal was a mouse created in 1974 by Rudolf Jaenisch. In 1976 the technology was commercialised, with the advent of genetically modified bacteria that produced somatostatin, followed by insulin in 1978. In 1983 an antibiotic resistant gene was inserted into tobacco, leading to the first genetically engineered plant. Advances followed that allowed scientists to manipulate and add genes to a variety of different organisms and induce a range of different effects. Plants were first commercialized with virus resistant tobacco released in China in 1992. The first genetically modified food was the Flavr Savr tomato marketed in 1994. By 2010, 29 countries had planted commercialized biotech crops. In 2000 a paper published in Science introduced golden rice, the first food developed with increased nutrient value.
Genetic engineering techniques allow the modification of animal and plant genomes. Techniques have been devised to insert, delete, and modify DNA at multiple levels, ranging from a specific base pair in a specific gene to entire genes. There are a number of steps that are followed before a genetically modified organism (GMO) is created. Genetic engineers must first choose what gene they wish to insert, modify, or delete. The gene must then be isolated and incorporated, along with other genetic elements, into a suitable vector. This vector is then used to insert the gene into the host genome, creating a transgenic or edited organism.
Transient expression, more frequently referred to "transient gene expression", is the temporary expression of genes that are expressed for a short time after nucleic acid, most frequently plasmid DNA encoding an expression cassette, has been introduced into eukaryotic cells with a chemical delivery agent like calcium phosphate (CaPi) or polyethyleneimine (PEI). However, unlike "stable expression," the foreign DNA does not fuse with the host cell DNA, resulting in the inevitable loss of the vector after several cell replication cycles. The majority of transient gene expressions are done with cultivated animal cells. The technique is also used in plant cells; however, the transfer of nucleic acids into these cells requires different methods than those with animal cells. In both plants and animals, transient expression should result in a time-limited use of transferred nucleic acids, since any long-term expression would be called "stable expression."
Tsune Kosuge was an American plant pathologist and plant biochemist who researched plant–microbe interactions. He was particularly known for his work on bacterial-synthesized plant hormones in plant tumors. He was a professor in the department of plant pathology at the University of California, Davis, from 1971 until his death, serving as departmental chair (1974–80).
The bacterial type IV secretion system, also known as the type IV secretion system or the T4SS, is a secretion protein complex found in gram negative bacteria, gram positive bacteria, and archaea. It is able to transport proteins and DNA across the cell membrane. The type IV secretion system is just one of many bacterial secretion systems. Type IV secretion systems are related to conjugation machinery which generally involve a single-step secretion system and the use of a pilus. Type IV secretion systems are used for conjugation, DNA exchange with the extracellular space, and for delivering proteins to target cells. The type IV secretion system is divided into type IVA and type IVB based on genetic ancestry.
Howard M. Goodman is an American molecular biologist and a professor of genetics emeritus at Massachusetts General Hospital. He is best known for his role in founding the department of molecular biology at Massachusetts General Hospital.
References
- ↑ "Patricia C. Zambryski". Plant & Microbial Biology | University of California, Berkeley. Retrieved 2022-05-02.
- 1 2 3 "Patricia C. Zambryski | Department of Plant & Microbial Biology | UC Berkeley". 2016-03-16. Archived from the original on 2016-03-16. Retrieved 2022-05-02.
- 1 2 Privalle, Laura S. (2017-03-08). Women in Sustainable Agriculture and Food Biotechnology: Key Advances and Perspectives on Emerging Topics. Springer. pp. 10–11. ISBN 978-3-319-52201-2.
- ↑ Zambryski, Patricia; Holsters, Marcelle; Kruger, Kelly; Depicker, Ann; Schell, Josef; Van Montagu, Marc; Goodman, Howard M. (1980-09-19). "Tumor DNA Structure in Plant Cells Transformed by A. tumefaciens". Science. 209 (4463): 1385–1391. Bibcode:1980Sci...209.1385Z. doi:10.1126/science.6251546. ISSN 0036-8075. PMID 6251546.
- ↑ Godwin, Ian D. (2019-01-18). Good Enough to Eat?: Next Generation GM Crops. Royal Society of Chemistry. ISBN 978-1-78801-681-0.
- ↑ Zambryski, P.; Joos, H.; Genetello, C.; Leemans, J.; Van Montagu, M.; Schell, J. (1983). "Ti plasmid vector for the introduction of DNA into plant cells without alteration of their normal regeneration capacity". The EMBO Journal. 2 (12): 2143–2150. doi:10.1002/j.1460-2075.1983.tb01715.x. PMC 555426 . PMID 16453482.
- ↑ Schmeck, Harold M. (October 6, 1983). Gene-splicing of plants makes advance. Sarasota Herald-Tribune.
- ↑ Zambryski, Patricia; Crawford, Katrina (2000). "Plasmodesmata: Gatekeepers for Cell-to-Cell Transport of Developmental Signals in Plants". Annual Review of Cell and Developmental Biology. 16 (1): 393–421. doi:10.1146/annurev.cellbio.16.1.393. ISSN 1081-0706. PMID 11031242.
- ↑ Burch-Smith, Tessa M.; Zambryski, Patricia C. (2012-06-02). "Plasmodesmata Paradigm Shift: Regulation from Without Versus Within". Annual Review of Plant Biology. 63 (1): 239–260. doi:10.1146/annurev-arplant-042811-105453. ISSN 1543-5008. PMID 22136566.
- ↑ "Patricia C. Zambryski". www.nasonline.org. Retrieved 2022-05-02.