Phospholipid synthesis during the cell division cycle of Escherichia coli

Pierucci, O

doi:10.1128/jb.138.2.453-460.1979

Cited by 44 publications

(26 citation statements)

References 29 publications

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“…The doubling in number of e-sites has been connected to the process of DNA replication. The time of doubling in rate of elongation is either supposed to coincide with initiation of replication ( WARD and GLASER 1971, DONACHIE et al 1976, MEACOCK et al 1978, PIERUCCI 1979) or termination (ZARITSKY and PRITCHARD 1973, ZARITSKY 1975, SARGENT 1975, GRO-VER et al 1977, WESTLING-HAGGSTROM 1978. Thus, in E. coli the number of chromosomal origins or termini seems to determine the number of e-sites per cell.…”

Section: Discussionmentioning

confidence: 99%

Stepwise increase of elongation rate in individual hyphae of Streptomyces granaticolor during outgrowth

Kretschmer¹

1988

J. Basic Microbiol.

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Starting with germinating spores of Streptornyces granaticolor, the kinetics of elongation of 3 types of outgrowing hyphae was determined. The 3 hyphal types were: first germ tube, second germ tube (which appeared from the same spores about 3 hours later) and branches arising from the first germ tubes. Taking photographs every fifth minute, with all hyphae a linear multiphasic elongation behaviour was found. Alternatively, periods with constant elongation rate (a) changed with steps at which a increased abruptly. Several successive shifts were observed until finally at a hyphal length of about 25 pm a constant maximum a of about 22 pm h -' was attained.The length of the periods during which a remained constant did not depend on either the hyphal type or the order of the period. On an average, a single period lasted 46.8 minutes.The lengths of the hyphae, at the time when a increased, corresponded for the first germ tubes to successively about 2.4.8 and 16 unit cells. With branchesand second germ tubes these lengthscorresponded to4and 10 unit cells.Concerning increase of a during each step the quotients were in the range between 1.3 and 2.0. Branches and second germ tubes started with twice the rate observed with first germ tubes and thus reached the maximum a after a reduced number of steps. Calculations indicated, that on principle a of each linear period was determined by the number of unit cells (nucleoids) present at its beginning.Earlier studies on the growth kinetics of Streptomycetes delt mainly with the development of whole mycelia. It was found that the total length of mycelial hyphae increased exponentially due to the exponential increase of the number of branches. The similarity of both kinetics led to the conclusion that the individual hyphae elongated with a constant elongation rate (a), i.e., hyphal growth was linear (SCHUHMANN and BERGTER 1976, KRETSCHMER 1982, ALLAN andPROSSER 1983). However, concerning the initial phase of outgrowth of hyphae (either from spores or from main hyphae during branching) before branching, contradictory results have been published. In Streptomyces hygroscopicus on rich as well as on minimal medium germ tubes elongated exponentially (but the doubling time decreased before branching started), while branches elongated rather linearly (SCHUHMANN and BERGTER 1976). In Streplomyces coelicoior on minimal medium both germ tubes as well as branch hyphae initially showed linear elongation, which increased in rate lateron (ALLAN and PROSSER 1983).For s. granaticolor germ tubes an exponential growth behaviour was found on rich medium (KRETSCHMER 1982).These controversies, indicating a rather complex growth behaviour of young hyphae, may be resolved by using a more detailed (nearly-kinematographic) mode of observation. The yet unbranched stage of Srreptomyces hyphae is of particular interest, because here they resemble single-cell Eubacteria. This paper describes quantitatively the elongation behaviour of young germ tubes and branches of S. granaticolor. It is characterized by an ...

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Section: Discussionmentioning

confidence: 99%

Stepwise increase of elongation rate in individual hyphae of Streptomyces granaticolor during outgrowth

Kretschmer¹

1988

J. Basic Microbiol.

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“…After termination of replication, the chromosomes are segregated and a septum is formed in the centre of the cell. The synthesis of membrane phospholipids undergoes an abrupt doubling in rate at a particular stage in the cycle (Pierucci, 1979;Joseleau-Petit et al, 1984). The rate of protein synthesis and mass increase is proportional to the ribosome concentration, which is tightly controlled by the growth rate (for review, see Lindahl and Zengel, 1986).…”

Section: Introductionmentioning

confidence: 99%

The Escherichia coli lov gene product connects peptidoglycan synthesis, ribosomes and growth rate.

1989

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Mecillinam, a beta‐lactam antibiotic which binds specifically to penicillin‐binding protein 2 (PBP2), blocks lateral cell‐wall elongation, induces spherical morphology and ultimately kills bacteria. We describe here a new mecillinam‐resistant mutant of Escherichia coli, the lov mutant. It possesses active PBP2, as evidenced by its rod shape in the absence of mecillinam (but not in its presence), its ability to filament when septation is inhibited, and its penicillin‐binding ability. The lov mutant grows slowly but seems to regulate its macromolecular parameters properly: cell volume, RNA content (ribosome concentration), and DNA content are appropriate for the growth rate, and the growth yield is identical to that of wild type. The lov mutation is located at 41 min on the E.coli genetic map and is recessive. Certain rpsL (StrR) mutations suppress the lov mutant's mecillinam resistance. The allele specificity of the suppression suggests that the lov gene product may interact directly with the ribosomes. The lov gene product thus seems to define a link between PBP2 (the mecillinam target) and the ribosomes; we propose that this link is involved in transmitting information on the growth rate (ribosome concentration) to the peptidoglycan synthesizing apparatus.

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“…Ohki [146] and Daniels [147] found an exponential mode of synthesis of both phospholipids, but they had synchronized their cultures by aligning the genome replication at its initiation stage, which does not necessarily entail a concurrent synchrony of the other cyclic events. Churchward and Holland [139], Hakenbeck and Messer [132], and Pierucci [148] have done similar studies, using cultures synchronized in Helmstetter's baby machine [112,113]. Only Pierucci found a bilinear mode of synthesis of total phospholipids.…”

Section: Protein and Lipid Synthesismentioning

confidence: 90%

The cell cycle ofEscherichia coliand some of its regulatory systems

Képès¹

1986

FEMS Microbiology Letters

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Phospholipid synthesis during the cell division cycle of Escherichia coli

Cited by 44 publications

References 29 publications

Stepwise increase of elongation rate in individual hyphae of Streptomyces granaticolor during outgrowth

Stepwise increase of elongation rate in individual hyphae of Streptomyces granaticolor during outgrowth

The Escherichia coli lov gene product connects peptidoglycan synthesis, ribosomes and growth rate.

The cell cycle ofEscherichia coliand some of its regulatory systems

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