ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

Hits per page

hits 1 - 2 | 2 hits

Sorting

Electronic Resource

Homologous recombination between plasmid DNA molecules in maize protoplasts (1991)

Lyznik, Leszek A. ; McGee, J. David ; Tung, Po-Yen ; [et al.]

Springer

Molecular genetics and genomics 230 (1991), S. 209-218

add to mindlist on the mindlist

Details

ISSN: 1617-4623

Keywords: Homologous recombination ; Protoplast transformation ; β-Glucuronidase ; Maize

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Summary The requirements for homologous recombination between plasmid DNA molecules have been studied using the PEG (polyethylene glycol)-mediated transformation system of maize (Zea mays L.) protoplasts coupled with the transient expression assay for β-glucuronidase (GUS). Two plasmids were introduced into maize protoplasts; one plasmid (pB×26) contained a genomic clone of the Adh1 maize gene; the other plasmid (piGUS) was a promoterless construction containing part of intron A of the Adhl gene fused to the gusA coding sequence. Thus, the two vectors shared an effective homologous region consisting of a 459 by (Hindlll—PvuII) fragment of the yAdh1 intron A sequence. An active gusA fusion gene would result upon homologous recombination between the plasmids within the intron A sequence, and indeed GUS activity was observed in extracts following co-transformation of maize protoplasts with the two plasmids. The presence of recombinant DNA molecules in protoplast DNA isolated 1 day after co-transformation was verified using polymerase chain reactions (PCR) and Southern blots. For efficient homologous recombination, both plasmids had to be linearized. The recombination reaction was induced by restriction of the plasmid molecules either inside the effective homologous region or at the borders of the intron sequence. However, the presence of even small, terminal, nonhomologous sequences at the 3′ end of the pB×26 fragment inhibited the recombination reaction. Also, both ends of the linearized piGUS DNA molecules were involved in the recombination reaction. The results revealed some features of homologous recombination reactions occurring in plant cells which cannot be accommodated by mechanisms postulated for similar reactions in animal system and in lower eukaryotes.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00290670

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

Electronic Resource

Hydrogels based on copolymers of N-(2-hydroxyethyl) methacrylamide, 2-hydroxyethyl methacrylate, and 4-t-butyi-2-hydroxycyclohexyl methacrylate (1993)

Friends, G. ; Künzler, J. ; McGee, J. ; [et al.]

New York, NY [u.a.] : Wiley-Blackwell

Journal of Applied Polymer Science 49 (1993), S. 1869-1876

add to mindlist on the mindlist

Details

ISSN: 0021-8995

Keywords: Chemistry ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics

Notes: A nonionic, high water content, high-strength hydrogel based on N-(2-hydroxyethyl)methacrylamide (HMA), 2-hydroxyethyl methacrylate (HEMA), and a strengthening agent, 4-t-butyl-2-hydroxycyclohexyl methacrylate (TBCM). The HMA was prepared by the reaction of methacryloyl chloride with ethanol amine. The copolymerization of HMA with varying concentrations of HEMA and TBCM resulted in transparent hydrogel films possessing a wide range of mechanical and physical properties. A copolymer composition of 79 parts HMA, 20.7 parts TBCM, and 0.3 parts ethylene glycol dimethacrylate (EGDMA) gave a transparent, flexible film possessing a water content of 72.6%, a Young's modulus of 0.45 MPa, oxygen permeability of 28 barrers, and a tear strength of 28 N/m. In contrast, a copolymer composition of 40 parts HMA, 59.7 parts TBCM, and 0.3 parts EGDMA gave a hard, transparent film possessing a water content of 33% and a modulus of 504 MPa. © 1993 John Wiley & Sons, Inc.

Additional Material: 4 Ill.