Spheroplasts were prepared from two carotenoid pigment mutants of Mycobacterium aurum named NgR9 and A11, which were obtained by the chemical mutagenesis of the wild type strain A+ with N-methyl-N'-nitro-N-nitrosoguanidine. The carotenoid pigments and the alpha- and beta-mycolic acids were taken as genetic markers and the recombinants were selected on the basis of their colour on Löwenstein-Jensen medium. Spheroplasts of the two mutants were mixed in a 1:1 ratio and were treated with 40% (w/v) polyethylene glycol 6000 for 5 min at 37 degrees C. The frequency of NgR9 X A11 recombination in optimal conditions was about 2.5 X 10(-3). The recombinants selected on the basis of their carotenoid pigment profile were also tested for their alpha- and beta-mycolic acids as a second genetic marker. The results were further confirmed by electron microscopy. The optimal conditions for spheroplast fusion as a mode of genetic recombination in M. aurum are described.
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http://dx.doi.org/10.1099/00221287-129-4-1227 | DOI Listing |
Science
March 2024
Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Large DNA assembly methodologies underlie milestone achievements in synthetic prokaryotic and budding yeast chromosomes. While budding yeast control chromosome inheritance through ~125-base pair DNA sequence-defined centromeres, mammals and many other eukaryotes use large, epigenetic centromeres. Harnessing centromere epigenetics permits human artificial chromosome (HAC) formation but is not sufficient to avoid rampant multimerization of the initial DNA molecule upon introduction to cells.
View Article and Find Full Text PDFACS Synth Biol
November 2023
Univ. Bordeaux, INRAE, Biologie du Fruit et Pathologie, UMR 1332, F-33140 Villenave d'Ornon, France.
The genetic engineering of genome fragments larger than 100 kbp is challenging and requires both specific methods and cloning hosts. The yeast is considered as a host of choice for cloning and engineering whole or partial genomes from viruses, bacteria, and algae. Several methods are now available to perform these manipulations, each with its own limitations.
View Article and Find Full Text PDFbioRxiv
June 2023
Department of Biochemistry and Biophysics.
Large DNA assembly methodologies underlie milestone achievements in synthetic prokaryotic and budding yeast chromosomes. While budding yeast control chromosome inheritance through ~125 bp DNA sequence-defined centromeres, mammals and many other eukaryotes use large, epigenetic centromeres. Harnessing centromere epigenetics permits human artificial chromosome (HAC) formation but is not sufficient to avoid rampant multimerization of the initial DNA molecule upon introduction to cells.
View Article and Find Full Text PDFNanoscale
October 2022
Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK.
Synthetic biology and cellular engineering require chemical and physical alterations, which are typically achieved by fusing target cells with each other or with payload-carrying vectors. On one hand, electrofusion can efficiently induce the merging of biological cells and/or synthetic analogues the application of intense DC pulses, but it lacks selectivity and often leads to uncontrolled fusion. On the other hand, synthetic DNA-based constructs, inspired by natural fusogenic proteins, have been shown to induce a selective fusion between membranes, albeit with low efficiency.
View Article and Find Full Text PDFViruses
April 2021
J. Craig Venter Institute, 4120 Capricorn Lane, La Jolla, CA 92037, USA.
Sindbis virus (SINV), a positive-sense single stranded RNA virus that causes mild symptoms in humans, is transmitted by mosquito bites. SINV reverse genetics have many implications, not only in understanding alphavirus transmission, replication cycle, and virus-host interactions, but also in biotechnology and biomedical applications. The rescue of SINV infectious particles is usually achieved by transfecting susceptible cells (BHK-21) with SINV-infectious mRNA genomes generated from cDNA constructed via in vitro translation (IVT).
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