Abstract
In Escherichia coli the process of spontaneous zygogenesis (Z-mating), i.e. complete genetic mixing in the absence of a conjugative plasmid, was investigated further. Spontaneous-zygogenesis-promoting (Szp+) cells displayed strong clustering with each other and with ordinary F− cells in the optimal cell density range for Z-mating. When induced to rounding by the drug mecillinam, they aggregated into large, dense, stainable syncytium-like cells leaving giant ghosts upon lysis. In Z-mating mixtures of mecillinam-treated cells, these giant cells co-purified with mating products as other cells died. Giant cells recovering from mecillinam treatment yielded monstrous, branching forms, whereas non-Szp+ coccal cells reverted to rods in one step, and some 29% of the colonies formed were identified as deriving from entities possessing two distinct genomes. Z-mating was examined between E. coli and a distantly related Serratia marcescens strain. In the presence of calcium, mecillinam-rounded cells of a stable non-complementing diploid hybrid with the E. coli phenotype segregated normally dividing cells of the Serratia form.
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References
Achtman M, Morelli G, Schwuchow S (1978) Cell-cell interactions in conjugating Escherichia coli: role of f-pili and fate of mating aggregates. J Bacteriol 135:1053–1061
Bi E, Lutkenhaus J (1992) Isolation and characterization of fts alleles that affect septal morphology. J Bacteriol 174:5414–5423
Curtiss R (1964) A stable partial diploid strain of Escherichia coli. Genetics 50:679–694
Elseviers D, Cunin R, Glansdorff N (1972) Control regions within the argECBH gene cluster of Escherichia coli K12. Mol Gen Genet 117:349–366
Goodell EW, Schwartz U (1975) Sphere-rod morphogenesis of Escherichia coli. J Gen Microbiol 86:201–209
Grandjean V, Le Hegarat F, Hirschbein L (1996) Prokaryotic model of epigenetic inactivation: chromosomal silencing in Bacillus subtilis fusion products. In: Russo V, Martiensen RA, Riggs AD (eds) Epigenetic mechanisms of gene regulation. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, pp 361–376
Gratia JP (1962) Effect of multisite mutation to colicine resistance on recombination and segregation in E. coli K12. Nature 196:1337–1340
Gratia JP (1994) Ufr/s variation in Escherichia coli K12: a reversible double-mutation or alternate chromosome expression in non-complementing diploids? Res Microbiol 145:309–325
Gratia JP (1997) Effects of Ca2+ cations on survival, growth and cell size of Serratia marcescens SMG40 exposed to mecillinam. Arch Physiol Biochem 105:347–357
Gratia JP (2005) Non complementing diploidy resulting from spontaneous zygogenesis in Escherichia coli. Microbiol 151:2947–2959
Gratia JP (2007) Spontaneous zygogenesis, a wide-ranging mating process in bacteria. Res Microbiol (in press)
Gratia JP, Thiry M (2003) Spontaneous zygogenesis in Escherichia coli, a form of true sexuality in prokaryotes. Microbiol 149:2571–2584
Grimont PAD, Grimont F (1978) The genus Serratia. Ann Rev Microbiol 32:221–248
James R, Haga JY, Pardee AB (1975) Inhibition of an early event in the cell division cycle of Escherichia coli by Fl-1060, an amidinopenicillanic acid. J Bacteriol 122:1283–1292
Lederberg J (1949) Aberrant heterozygotes in Escherichia coli. Proc Natl Acad Sci USA 35:178–184
Lund F, Tybring L (1972) 6-B-amidinopenicillanic acids: a new group of antibiotics. Nature (Lond) New Biol 236:135–137
Miller JH (1972) Experiments in molecular genetics. Cold Spring Harbor Laboratory. Cold Spring Harbor
Ogg JE, Humphrey RD (1963) Small-cell segregants from a possibly homozygous diploid strain of Escherichia coli. J Bacteriol 85:801–807
Ogg JE, Zelle MR (1953) Isolation and characterization of a large cell possibly polyploid strains of Escherichia coli. J Bacteriol 74:477–484
Spratt BG (1975) Distinct penicillin-binding proteins involved in division, elongation, and shape of Escherichia coli. Proc Natl Acad Sci USA 72:2999–3003
Tyurin MV, Doroshenko VG, Oparina NYu (1997) Electrofusion of Escherichia coli cells. Membr Cell Biol 11:121–129
Wohlhieter JA, Gemski P, Baron LS (1975) Extensive segments of the Escherichia coli K12 chromosome in Proteus mirabilis diploids. Mol Gen Genet 139:93–101
Acknowledgments
I am indebted to D. Dekegel for assistance in microscopy. I also warmly thank Dr C. Godard for hospitality in her laboratory. I deeply acknowledge the help of K. Broman with writing the manuscript. I thank N. Glansdorff for critically reading the manuscript.
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Communicated by Jorge Membrillo-Hernández.
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Gratia, JP. Spontaneous zygogenesis (Z-mating) in mecillinam-rounded bacteria. Arch Microbiol 188, 565–574 (2007). https://doi.org/10.1007/s00203-007-0277-y
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DOI: https://doi.org/10.1007/s00203-007-0277-y