Growth of Bacteria

Novick, Aaron

doi:10.1146/annurev.mi.09.100155.000525

Cited by 177 publications

(76 citation statements)

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“…The experimental data presented in this paper show conclusively that a continuous culture is an inherently stable system adjusting itself automatically to changes in dilution rate. Any number of steady states can be obtained at difl'erent dilution rates anywhere between zero and the critical value, as the theories of Monod (1950) and Novick & Szilard (1950) predict.…”

Section: Discussionmentioning

confidence: 99%

“…for glucose, mannitol and lactose respectively), but considerably higher than the value of pg./ml. found by Novick & Szilard (1950) with tryptophan as substrate. The above values of ,urn, K , and Y were used in calculating the ' theoretical ' curves shown in Fig.…”

Section: Maintenance Of P U R I T Y Of Culturementioning

confidence: 93%

“…Monod (1942) first showed that there is a simple relationship between the specific growth rate and the concentration of an essential growth substrate, p being proportional to the substrate concentration when this is low but reaching a limiting saturation value a t high substrate concentrations according to the equation It follows from equation (3) that exponential growth can occur at specific growth rates having any value hetween zero and ,urn, provided the substrate concentration can be held constant at the appropriate value-a fact of major importance in continuous culture (Monod, 1950;Novick & Szilard, 1950). Monod (1942) also showed that there is a simple relationship between growth and utilization of substrate.…”

Section: General Principles Of Continuous Flow Systemsmentioning

confidence: 99%

“…the curve relating dilution rate to the Concentration of substrate in the culture vessel is the same whatever the concentration of substrate in the inflowing culture medium (cf. Novick & Szilard, 1950). In other words, when the dilution rate is fixed, the substrate concentration must come to a level (determined by equation 9) that makes p equal to D, and this level is independent of sR.…”

Section: K S + S Rmentioning

confidence: 99%

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The Continuous Culture of Bacteria; a Theoretical and Experimental Study

Herbert¹,

Elsworth²,

Telling³

1956

Journal of General Microbiology

980

416

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SUMMARY: A theoretical treatment of continuous culture is given, which allows quantitative prediction of the steady-state concentrations of bacteria and substrate in the culture, and how these may be expected to vary with change of medium, concentration and flow-rate. The layout and operation of a small pilot plant for the continuous culture of bacteria are described. This plant has been operated continuously for periods of up to 4 months without breakdown or contamination of the culture. No alterations in the properties of the organisms studied have occurred during such periods of continuous culture. Results are given of a series of experiments on the continuous culture of Aerobacter cloacae in a chemically defined medium, designed to allow quantitative comparison with the results predicted by the theory. The relative advantages of batch and continuous culture as production processes are discussed, and it is concluded that continuous culture may usually be expected to show a five to tenfold increase in output as compared with a batch process.The continuous culture of micro-organisms is a technique of increasing importance in microbiology. The essential feature of this technique is that microbial growth in a continuous culture takes place under steady-state conditions; that is, growth occurs a t a constant rate and in a constant environment. Such factors as pH value, concentrations of nutrients, metabolic products and oxygen, which inevitably change during the ' growth cycle ' of a batch culture, are all maintained constant in a continuous culture; moreover, they may be independently controlled by the experimenter. These features of the continuous culture technique make it a valuable research tool, while it offers many advantages, in the form of more economical production techniques, to the industrial microbiologist. Nevertheless, the technique has so far been comparatively little used. (The review of Novick (1955) lists nearly all the work on the subject that has yet appeared.) The reasons for this relative neglect are, we believe, twofold.The first reason is the lack of a generally accepted theoretical background. Continuous culture presents theoretical problems of an essentially kinetic nature which must be solved before the technique can be intelligently applied.

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Section: Discussionmentioning

confidence: 99%

Section: Maintenance Of P U R I T Y Of Culturementioning

confidence: 93%

Section: General Principles Of Continuous Flow Systemsmentioning

confidence: 99%

Section: K S + S Rmentioning

confidence: 99%

See 2 more Smart Citations

The Continuous Culture of Bacteria; a Theoretical and Experimental Study

Herbert¹,

Elsworth²,

Telling³

1956

Journal of General Microbiology

980

416

View full text Add to dashboard Cite

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“…2, lanes 1-6) with the recombinant (co-integrant) species (composed of pRW4316 and pRW4312). The co-existence of pRW4312 and the recombinant plasmid, despite both being replicated by the ColE1 replicon, may be attributed to the ability of antibiotic selective pressure to overcome the statistical plasmid incompatibility observed in the absence of selection (55,56).…”

Section: Table II Plasmids Used In This Studymentioning

confidence: 99%

Long CTG·CAG Repeats from Myotonic Dystrophy Are Preferred Sites for Intermolecular Recombination

Pluciennik

Iyer

Напиерала

et al. 2002

Journal of Biological Chemistry

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Homologous recombination was shown to enable the expansion of CTG⅐CAG repeat sequences. Other prior investigations revealed the involvement of replication and DNA repair in these genetic instabilities. Here we used a genetic assay to measure the frequency of homologous intermolecular recombination between two CTG⅐CAG tracts. When compared with non-repeating sequences of similar lengths, long (CTG⅐CAG) n repeats apparently recombine with an ϳ60-fold higher frequency. Sequence polymorphisms that interrupt the homogeneity of the CTG⅐CAG repeat tracts reduce the apparent recombination frequency as compared with the pure uninterrupted repeats. The orientation of the repeats relative to the origin of replication strongly influenced the apparent frequency of recombination. This suggests the involvement of DNA replication in the recombination process of triplet repeats. We propose that DNA polymerases stall within the CTG⅐CAG repeat tracts causing nicks or double-strand breaks that stimulate homologous recombination. The recombination process is RecA-dependent.Micro-and minisatellite instability has been associated with human genetic diseases (1-4). Approximately 14 hereditary neurological diseases are caused by the genetic instabilities of triplet repeat sequences (TRS) 1 in or near relevant genes (reviewed in Ref. 1). Long tracts of repeating CTG⅐CAG sequences are responsible for myotonic dystrophy and several other diseases. Normal individuals have 5-37 repeats in the myotonic dystrophy protein kinase gene, whereas the mutations (expansions) can be in the range of 50 -3000 repeats. Thus, an explosive allele length change during intergenerational transmission can occur in this autosomal dominant disease, thus causing an increase in the severity of the disease and a decrease of the age at onset (anticipation).The mechanisms of genetic instabilities have been widely investigated in the past 6 years (1). DNA replication (5-8) and repair including methyl-directed mismatch repair (9 -11), nucleotide excision repair (12), DNA polymerase III exonucleolytic proofreading (13), and double-strand break repair (14) have been implicated.Repetitive sequences promote homologous recombination in prokaryotic as well as eukaryotic systems, presumably by virtue of forming unusual DNA secondary structures (15)(16)(17)(18)(19)(20)(21)(22). In fact, homologous recombination has been implicated in the instability of repetitive sequences (23-26). Similar findings have also been made with CTG⅐CAG repeats using a two-plasmid system in Escherichia coli (27,28). Multiple fold expansions, deletions, and the exchange of point mutations between tracts were found in this system; these events were dependent on the presence of TRS tracts on both plasmids, CTG⅐CAG repeat lengths longer than 30, and a functional recA gene.Previously (29), it was proposed that CTG⅐CAG tracts might function as recombination hot spots in the bovine genome. More recently, Young et al. (30) surveyed the genome of Saccharomyces cerevisiae and suggested that these repeats cou...

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