CHARACTERIZATION OF LOOSELY ASSOCIATED MATERIAL FROM THE CELL-SURFACEOF LACTOCOCCUS-LACTIS SUBSP CREMORIS-E8 AND ITS PHAGE-RESISTANT VARIANT STRAIN-398
Pk. Gopal et Vl. Crow, CHARACTERIZATION OF LOOSELY ASSOCIATED MATERIAL FROM THE CELL-SURFACEOF LACTOCOCCUS-LACTIS SUBSP CREMORIS-E8 AND ITS PHAGE-RESISTANT VARIANT STRAIN-398, Applied and environmental microbiology, 59(10), 1993, pp. 3177-3182
Loosely associated material (LAM) was isolated by gentle extraction pr
ocedures from the cell surface of Lactococcus lactis subsp. cremoris E
8 and its phage-resistant variant strain 398. LAM from both strains wa
s chemically characterized, and its role in the adsorption of three sm
all isometric bacteriophages, PHI 618, PHI 833, and PHI 852, to the ce
ll surface of the two strains was investigated. The phage-resistant st
rain (strain 398) produced LAM which differed significantly from the m
aterial produced by the parent strain. The total yield of LAM from str
ain 398 was two- to threefold higher than that from strain E8, and the
material contained fivefold more rhamnose and twofold more galactose.
Polyacrylamide gel electrophoretic analysis showed that LAM from stra
in 398 lacked a 21-kDa protein which was present in LAM from the paren
t strain. Inhibition studies of phage binding by using isolated LAM fr
om two strains showed that although LAM from strain E8 reduced the tit
er of PHI 618 and PHI 852 by 53 and 82% respectively, LAM from strain
398 had no effect on the plaque-forming ability of any of the three ph
ages tested. Treatment of LAM from strain E8 with sodium metaperiodate
destroyed its ability to bind with PHI 618 and PHI 852. Phenotypicall
y, strain 398 differed from its parent strain E8 in that it was more p
rone to cell lysis and required an osmotically adjusted buffer system
for the extraction of LAM.