HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Klaenhammer, T. R. Articles by McKay, L. L. Search for Related Content PubMed PubMed Citation Articles by Klaenhammer, T. R. Articles by McKay, L. L.

Isolation and Examination of Transducing Particles from Streptococcus lactis C2¹ ,^,2

Department of Food Science and Nutrition, University of Minnesota, St. Paul 55108

ABSTRACT

Two defective transducing bacteriophages induced by exposure of Streptococcus lactis C2 to ultraviolet irradiation have been isolated and characterized. These temperate phages designated c2t₁ and c2t₂ were isolated by cesium chloride equilibrium density gradient centrifuga-tion of phage preparations concentrated by polyethylene glycol precipitation. The equilibrium gradient contained two visually apparent phage bands positioned at densities of 1.487 and 1.463 g cm^-3 respective for c2t₁ and c2t₂. Particle morphology and phenol extracted phage deoxyribonucleic acid were examined by electron microscopy for each phage. Head diameter, deoxyribonucleic acid length, and molecular weight for c2t₁ were 60 nm, 10.9 µm, and 22.6 x 10⁶ daltons, respectively. Phage c2t₂ had a head diameter of 70nm, a deoxyribonucleic acid length of 11.4 µm, and a molecular weight of 23.8 x 10 daltons. Comparing head diameter and phage deoxyribonucleic acid length suggests that the variation in c2t₁ and c2t₂ density was due to difference in head size. Phage c2t₂ exhibited high frequency transduction of lactose metabolism based on preparations equilibrated by adjustment of optical density at 260 nm. Maltose and proteinase markers also were transduced by both phages. The transducing phage was defective, requiring a helper for the formation of transducing particles but not for the transduction process. Superinfection immunity was not conferred on post-infecting phage. The results demonstrated transduction by two nonidentical phage particles lysogenic for S. lactis C2.

¹ Scientific Journal Series Paper No. 9104, Minnesota Agricultural Experiment Station, University of Minnesota, St. Paul 55108.

² This work was taken from a thesis submitted by T. R. Klaenhammer to the faculty of the Graduate School of the University of Minnesota in partial fulfillment for the degree of Master of Science.