Directed selection of differentiation mutants of <i>Streptomyces noursei</i> using chemostat cultivation

Noack, D.

doi:10.1002/jobm.3620260412

Cited by 17 publications

(3 citation statements)

References 25 publications

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“…Hop wood, John Innes Institute, Norwich, UK, was routinely cultured and maintained as described elsewhere (Allan & Prosser, 1983). Growth experiments were carried out in a glucose mineral salts broth, adapted from Noack (1986) and containing [g (l distilled water) –1 ] KH 2 PO 4 , 2·72; Na 2 PO 4 .2H 2 O, 7·16; NaCl, 5·097; Na 2 SO 4 , 1·065; MgCl 2 .6H 2 O, 0·04; FeCl 2 , 0·005; NH 4 C1, 0·4; Casamino acids (Difco), 5; d -glucose, 0·5. All components, except glucose, were sterilized by autoclaving for 15 min at 121 °C (15 p.s.i.…”

Section: Methodsmentioning

confidence: 99%

Experimental verification of a mathematical model for pelleted growth of Streptomyces coelicolor A3(2) in submerged batch culture

Tough

Prosser

1996

Microbiology

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A published mathematical model for growth of pellets of filamentous microorganisms has been tested by comparison of model predictions with experimental data on growth of Streptomyces coe/ico/or in liquid batch culture. The original model considered the classification of pellets into a range of size classes. Growth resulted in movement of pellets to classes of increasing size, while shear forces produced mycelial fragments which entered the smallest size class, from which they grew to form further pellets. This model did not correctly describe changes in pellet size distributions during growth and was therefore modified in two ways. In the first, new pellets were assumed to be formed by the break-up, by shear forces, of existing pellets into two pellets of equal size, rather than removal of small hyphal fragments from the pellet surface. The second modification assumed that the outer shell of active mycelial biomass had a density less than 1 g em-) and that hyphal density within this shell decreased with distance from the pellet centre. The modified model generated predictions which agreed closely with experimental data on biomass concentration, pellet size distribution, pellet number and pellet radius during batch growth, thereby supporting the assumptions on which the model was based. The model did not accurately describe final biomass concentration, through lack of Consideration of autolysis of mycelia at the centre of larger pellets in which growth was limited by diffusion of nutrients. Attempts to incorporate autolysis into the model improved prediction of biomass concentration but were not based on sound biological assumptions and increased the complexity of the model. Further experimental work is required for accurate description of the effects of autolysis on pellet growth.

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Section: Methodsmentioning

confidence: 99%

Experimental verification of a mathematical model for pelleted growth of Streptomyces coelicolor A3(2) in submerged batch culture

Tough

Prosser

1996

Microbiology

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“…Noack and Roth (1986) described selection mechanisms during contiuous cultures of S. noursei. It is assumed for the experiments shown here that a mutant with a higher growth rate and less productivity of secondary metabolites evolved due to selection mechanisms.…”

Section: Productionmentioning

confidence: 99%

Continuous cultivation of Streptomyces tendae in different media

Lohr

Buschulte

Gilles

1989

Appl Microbiol Biotechnol

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The strain Streptomyces tendae is well suited for continuous cultivation because of its ability to grow and produce secondary metabolites simultaneously. Continuous culture experiments on defined medium show that growth is limited by nitrogen during steady state for the given medium composition. It is supposed that this also holds for complex medium. Production of antibiotics (several nikkomycins) occurs simultaneously with exponential growth. After switching from batch to continuous operation the fraction of biomass, consisting of pellets, decreases permanently.

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“…The correlation of nourseothricin resistance and acetyltransferase activity was studied in strains with different nourseothricin sensitivity. Mutants of the high producing strain Streptomyces noursei NC: 13 which exhibited different nourseothricin sensitivity and different antibiotic productivity were isolated after continuous cultivation (NOACK 1986).…”

Section: Hauft H Thrunrt and D N O A C~mentioning

confidence: 99%

Self‐resistance of the nourseothricin‐producing strain Streptomyces noursei

Haupt¹,

Thrum²,

Noack³

1986

J. Basic Microbiol.

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The nourseothricin producer Streptomyces noursei is resistant to its own antibiotic in submerged as well as in surface culture. The strain shows no cross-resistance to miscoding inducing aminoglycoside antibiotics. Cell free extracts of Streptomyces noursei inactivate nourseothricin by enzymatic acetylation. The pattern of cross-resistance of Streptomyces noursei correlates well with the substrate specificity of the nourseothricin acetyltransferase. Furthermore, the acetyltransferase activity parallels the resistance level in nourseothricin-producing strains and nonproducing mutants. The results suggest that the nourseothricin acetyltransferase is important in the self-defence strategy of the nourseothricin-producing strain.

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Directed selection of differentiation mutants of Streptomyces noursei using chemostat cultivation

Cited by 17 publications

References 25 publications

Experimental verification of a mathematical model for pelleted growth of Streptomyces coelicolor A3(2) in submerged batch culture

Experimental verification of a mathematical model for pelleted growth of Streptomyces coelicolor A3(2) in submerged batch culture

Continuous cultivation of Streptomyces tendae in different media

Self‐resistance of the nourseothricin‐producing strain Streptomyces noursei

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