The Axenic Culture of Strains of the Various Syngens of Paramecium aurelia*

Wagtendonk, W. J. Van; Goldman, Phyllis H.; Smith, W. L.

doi:10.1111/j.1550-7408.1970.tb04699.x

Cited by 8 publications

(2 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since these unicells have no synapses or neural organization other than the cell membrane, analysis of altered membrane function is further simplified. Pure clones of various genotypes can be grown axenically (13) for biochemical analysis and comparisons and for immunological studies. The development of behavioral genetics in this organism rests on an extensive foundation of Paramecium genetics (15), and exploits the advantage of autogamy, a process of nuclear reorganization in P. aurelia that makes detection of mutants nearly as easy as in haploid organisms.…”

mentioning

confidence: 99%

Genetic Modification of Electric Properties in an Excitable Membrane

Kung

Eckert

1972

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

A behavioral deficiency produced by a single gene mutation in Paramecium aurelia was traced to impaired electric excitability of the cell membrane. Evidence is presented that the mutant membrane does not exhibit the normal depolarization-activated increasein calcium conductance responsible for regenerative depolarization in the wild type. Other electric properties characteristic of the wild-type membrane remain normal in the mutant.A major unsolved problem in neurobiology is the mechanism of negative resistance in electrically excitable membranes. After a sudden depolarization, the membrane exhibits a transient increased conductance to an ion, usually Na+ or Ca++, which then carries depolarizing charge into the cell. The additional depolarization results in a further increase in conductance, and thus the process becomes regenerative, driving the membrane voltage toward the equilibrium potential of the ion (1, 2). This regenerative behavior, which will be termed electric excitability, is responsible for the upstroke of an action potential. Although the electrical properties of excitable membranes have been studied intensively and have been described elegantly by the ionic hypothesis, virtually nothing is known about mechanisms of membrane excitation at the molecular levels of membrane structure and chemistry. One successful approach to the mechanism of biological functions has been to modify or delete a molecule responsible for one part of a complex function, and then to observe the effect on the function. Manipulations by gene mutation have been applied to studies of the nervous system by Benzer (3) in Drosophila melanogaster. This rationale is also behind the work of Kung (4, 5), which is directed at the genetic dissection of the excitable membrane of a ciliate, Paramecium aurelia.Paramecium is admirably suited for a genetic approach to the study of membrane excitation. This cell is electrically excitable (6-8) and lends itself to intracellular recording and stimulating techniques (9, 10). The locomotor behavior of this ciliate has been shown to correlate with the electrical activity of the membrane (7,11,12). Behavioral correlates of membrane activity greatly simplify the problem of recognizing altered membrane function in mutants (4,5). Since these unicells have no synapses or neural organization other than the cell membrane, analysis of altered membrane function is further simplified. Pure clones of various genotypes can be grown axenically (13) for biochemical analysis and comparisons and for immunological studies. The development of behavioral genetics in this organism rests on an extensive foundation of Paramecium genetics (15), and exploits the advantage of autogamy, a process of nuclear reorganization in P. aurelia that makes detection of mutants nearly as easy as in haploid organisms. Finally, a large fraction of the surface membrane of ciliates covers the cilia, and thus can be routinely harvested for fractionation (14). This paper reports electrophysiological studies on a mutant of P. aurelia...

show abstract

mentioning

confidence: 99%

Genetic Modification of Electric Properties in an Excitable Membrane

Kung

Eckert

1972

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…In 100: 5 axenic medium stock 299 containing lambda were maintained for only 5 weeks at 20' and 2 7 O , after which period the paramecia lost their particles. It is reported that stock 540 with mu particles will grow and maintain the particles in 40:4 medium (van Wagtendonk, Goldman & Smith, 1970). However, I have not been able to repeat this.…”

Section: Discussionmentioning

confidence: 80%

The Growth in vitro of Killer Particles from Paramecium aurelia and the Axenic Culture of this Protozoon

Williams

1971

Journal of General Microbiology

View full text Add to dashboard Cite

S U M M A R YParamecia belonging to certain strains of Parameciunz aurelia (syngens I , 2 and 8) were transferred from dual culture with bacteria to axenic media, where the growth of some stocks continued, with weekly subculturing. The only axenically grown stock found to be capable of supporting growth of mu particles indefinitely was stock 138 (syngen 8).Lambda and mu particles from axenically grown Paramecium aurelia were cultivated in vitro in a highly complex medium at 27O under aerobic conditions. The particles retained their characteristic killing action on certain P. aurelia stocks but could not infect sensitive paramecia. The particles divided at approximately one fission per day and achieved a maximum density of only 16-20 x 103/ml. The implications of these studies for the interaction of the nuclear genes and the killer particles are discussed.

show abstract

Publications

Grell¹

1973

Protozoology

View full text Add to dashboard Cite

The Axenic Culture of Strains of the Various Syngens of Paramecium aurelia*

Abstract: SYNOPSIS Strains of the various syngens of Paramecium aurelia respond differently to the culture media developed for Strain 299 of syngen 8. Not only is there a variety of response between the syngens, but strains belonging to the same syngen respond differently to the 3 growth media.

Cited by 8 publications

References 4 publications

Genetic Modification of Electric Properties in an Excitable Membrane

Genetic Modification of Electric Properties in an Excitable Membrane

The Growth in vitro of Killer Particles from Paramecium aurelia and the Axenic Culture of this Protozoon

Publications

Contact Info

Product

Resources

About