Wilcks A, Smidt L, Bahl M I, Hansen B M, Andrup L, Hendriksen N B, Licht T R
Department of Microbiology and Risk Assessment, National Food Institute, Technical University of Denmark, Søborg, Denmark.
J Appl Microbiol. 2008 May;104(5):1252-9. doi: 10.1111/j.1365-2672.2007.03657.x. Epub 2007 Nov 27.
To study the ability of Bacillus thuringiensis subsp. israelensis spores to germinate and subsequently transfer a conjugative plasmid in the intestinal tract of gnotobiotic rats.
Germination was studied by feeding germ-free rats with spores of a B. thuringiensis strain harbouring a plasmid encoding green fluorescent protein (GFP), which enabled quantification of germinated bacteria by flow cytometry. To study in vivo conjugation, germ-free rats were first associated with a B. thuringiensis recipient strain and after 1 week an isogenic donor strain harbouring the conjugative plasmid pXO16 was introduced. Both strains were given as spores and transfer of pXO16 was observed from the donor to the recipient strain.
Bacillus thuringiensis is able to have a full life cycle in the intestine of gnotobiotic rats including germination of spores, several cycles of growth and sporulation of vegetative cells. For the first time conjugative plasmid transfer in a mammalian intestinal tract was shown between two B. thuringiensis strains.
Strains of B. thuringiensis are used worldwide to combat insect pests, and this study brings new insights into the nature of B. thuringiensis showing the potential of the bacteria to germinate and transfer DNA in the mammalian intestinal tract.
研究苏云金芽孢杆菌以色列亚种孢子在无菌大鼠肠道内的萌发能力以及随后转移接合性质粒的能力。
通过给无菌大鼠喂食携带编码绿色荧光蛋白（GFP）质粒的苏云金芽孢杆菌菌株的孢子来研究萌发情况，这使得通过流式细胞术对萌发细菌进行定量成为可能。为了研究体内接合作用，首先将无菌大鼠与苏云金芽孢杆菌受体菌株建立联系，1周后引入携带接合性质粒pXO16的同基因供体菌株。两种菌株均以孢子形式给予，并观察到pXO16从供体菌株转移到受体菌株。
苏云金芽孢杆菌能够在无菌大鼠肠道内经历完整的生命周期，包括孢子萌发、营养细胞的多个生长周期和孢子形成。首次证明了在两种苏云金芽孢杆菌菌株之间在哺乳动物肠道内发生了接合性质粒转移。
苏云金芽孢杆菌菌株在全球范围内用于防治害虫，本研究为苏云金芽孢杆菌的特性带来了新的见解，表明该细菌在哺乳动物肠道内具有萌发和转移DNA的潜力。
