Isolation of a fast-growing strain of the rotifer Brachionus calyciflorus Pallas using turbidostat culture

Bennett, William N.; Boraas, Martin E.

doi:10.1016/0044-8486(88)90038-5

Cited by 20 publications

(10 citation statements)

References 21 publications

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“…Hereafter, we will denote by S σ a singular arc corresponding to a constant substrate concentration s = σ over a time interval I, which corresponds to an auxostat (see e.g [2]). In the invariant manifold F , a singular arc corresponds also to a turbidostat (i.e.…”

Section: Characterization Of the Singular Arcsmentioning

confidence: 99%

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Optimisation of strain selection in evolutionary continuous culture

Bayen¹,

Mairet

2016

International Journal of Control

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Section: Characterization Of the Singular Arcsmentioning

confidence: 99%

“…a constant biomass concentration). These operating modes are commonly used for strain selection (see e.g [2]). We now show that a singular arc is always admissible: Corollary 3.1.…”

Section: Characterization Of the Singular Arcsmentioning

confidence: 99%

Optimisation of strain selection in evolutionary continuous culture

Bayen¹,

Mairet

2016

International Journal of Control

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“…Continuous culture has long been an important tool in industrial strain development (Bloom & Mcfall, 1975;Harder et al, 1977;Bennett & Boraas, 1988) and has even been used to study ethanol tolerance in yeast. For example, Brown & Oliver (1982) selected ethanol-tolerant Saccharomyces uvarum strains in a chemostat by steadily increasing the ethanol concentration in proportion to the CO 2 output of the population.…”

Section: Introductionmentioning

confidence: 99%

Turbidostat culture of Saccharomyces cerevisiae W303-1A under selective pressure elicited by ethanol selects for mutations in SSD1 and UTH1

et al. 2012

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We investigated the genetic causes of ethanol tolerance by characterizing mutations selected in Saccharomyces cerevisiae W303‐1A under the selective pressure of ethanol. W303‐1A was subjected to three rounds of turbidostat, in a medium supplemented with increasing amounts of ethanol. By the end of selection, the growth rate of the culture has increased from 0.029 to 0.32 h−1. Unlike the progenitor strain, all yeast cells isolated from this population were able to form colonies on medium supplemented with 7% ethanol within 6 days, our definition of ethanol tolerance. Several clones selected from all three stages of selection were able to form dense colonies within 2 days on solid medium supplemented with 9% ethanol. We sequenced the whole genomes of six clones and identified mutations responsible for ethanol tolerance. Thirteen additional clones were tested for the presence of similar mutations. In 15 of 19 tolerant clones, the stop codon in ssd1‐d was replaced with an amino acid‐encoding codon. Three other clones contained one of two mutations in UTH1, and one clone did not contain mutations in either SSD1 or UTH1. We showed that the mutations in SSD1 and UTH1 increased tolerance of the cell wall to zymolyase and conclude that stability of the cell wall is a major factor in increased tolerance to ethanol.

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“…Monogononts normally reproduce by cyclical parthenogenesis, an alternation between ameiotic parthenogenesis and sporadic sexual episodes [13] . But there are also several documented cases on Brachionus strains that have permanently lost the ability to reproduce sexually [14] , [15] , [16] , [17] , [18] . In cyclical parthenogenetic rotifers, sex is initiated with the production of sexual females, whose oocytes undergo meiosis and develop into haploid males (if not fertilized), or diploid diapausing eggs (if fertilized).…”

Section: Introductionmentioning

confidence: 99%

Loss of Sexual Reproduction and Dwarfing in a Small Metazoan

et al. 2010

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BackgroundAsexuality has major theoretical advantages over sexual reproduction, yet newly formed asexual lineages rarely endure. The success, or failure, of such lineages is affected by their mechanism of origin, because it determines their initial genetic makeup and variability. Most previously described mechanisms imply that asexual lineages are randomly frozen subsamples of a sexual population.Methodology/Principal FindingsWe found that transitions to obligate parthenogenesis (OP) in the rotifer Brachionus calyciflorus, a small freshwater invertebrate which normally reproduces by cyclical parthenogenesis, were controlled by a simple Mendelian inheritance. Pedigree analysis suggested that obligate parthenogens were homozygous for a recessive allele, which caused inability to respond to the chemical signals that normally induce sexual reproduction in this species. Alternative mechanisms, such as ploidy changes, could be ruled out on the basis of flow cytometric measurements and genetic marker analysis. Interestingly, obligate parthenogens were also dwarfs (approximately 50% smaller than cyclical parthenogens), indicating pleiotropy or linkage with genes that strongly affect body size. We found no adverse effects of OP on survival or fecundity.Conclusions/SignificanceThis mechanism of inheritance implies that genes causing OP may evolve within sexual populations and remain undetected in the heterozygous state long before they get frequent enough to actually cause a transition to asexual reproduction. In this process, genetic variation at other loci might become linked to OP genes, leading to non-random associations between asexuality and other phenotypic traits.

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Isolation of a fast-growing strain of the rotifer Brachionus calyciflorus Pallas using turbidostat culture

Cited by 20 publications

References 21 publications

Optimisation of strain selection in evolutionary continuous culture

Optimisation of strain selection in evolutionary continuous culture

Turbidostat culture of Saccharomyces cerevisiae W303-1A under selective pressure elicited by ethanol selects for mutations in SSD1 and UTH1

Loss of Sexual Reproduction and Dwarfing in a Small Metazoan

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