A Capsule-depolymerizing Enzyme from Alcaligenes faecalis Infected with Bacteriophage A6

Maré, I. J.; Smit, J. A.

doi:10.1099/0022-1317-5-4-551

Cited by 12 publications

(3 citation statements)

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“…This probably reflects the slow rate of adsorption of the phages to the bacterial cell and a consequent wide variation in the time of initiation of the lytic cycle (8, 25); the presence of turbid haloes has also been ascribed to the possession of a capsule by the host bacterium (2,5,22). In the E. herbicola Y178 system, both capsulation and slow adsorption rate undoubtedly contributed to the observed plaque morphology.…”

Section: Discussionmentioning

confidence: 93%

“…The role of the capsule in determining the magnitude of these parameters is controversial: the capsule has been thought to present difficulties in the adsorption process (14), but in the case of a Klebsiella phage (23), and phage A6 of Alcaligenes faecalis (22), the capsule enhanced adsorption of the phage. As nothing is yet known about the attachment sites on E. herbicola Y178, it is not possible t o assess the significance of the capsule in this system.…”

Section: Discussionmentioning

confidence: 99%

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The isolation and characterization of a temperate phage, Y46/(E2), from Erwinia herbicola Y46

Harrison¹,

Gibbins²

1975

Can. J. Microbiol.

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A temperate phage was induced from exponential phase cells of Erwinia herbicola Y46 by treatment with mitomycin C. The phage was purified by single plaque isolation, and produced in bulk by successive cultivation in young cultures of E. herbicola Y 178. Phages were concentrated from culture filtrates by rate zonal centrifugation and resuspension in 0.02 M Tris buffer, pH 7.2, twice, yielding suspensions of about 5 times 10(11) PFU/ml. Purification was achieved by centrifugation in buffered sucrose solutions. The band at the 30/40% sucrose interface yielded intact particles having regular hexagonal heads and lonb contractile tails, with base plates. Fibers were not seen. The mean dimensions were head, 51 nm; neck length, 11 nm; overall tail length, extended, 98 nm and contracted, 75 nm; diameter of tail sheath, 24 nm. The phage was stable from pH 4.0 to 11.0, but unstable at pH 3.0, the response being independent of the suspending medium used. At pH 3.0, a survival curve having biphasic appearance was observed, which was not due to a mixed population of phages. Stability to heat was good up to 45 degrees C, above which a logarithmic decline with temperature increase occurred. The average inactivation rate constant at 50 degrees C and pH 6.8 was 0.15 min-1. Adsorption to E. herbicola Y 178 cells exhibited first-order kinetics, the adsorption rate constant being 2.5 times 10(-10) ml/min. One-step growth-curve experiments indicated a burst size of 35-40, and a minimum latent period of 80 min. Probit analysis gave a mean latent period of 140 min (SD 25). The phage caused lysis of only E. herbicola strains Y178 and Y186.

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Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 99%

The isolation and characterization of a temperate phage, Y46/(E2), from Erwinia herbicola Y46

Harrison¹,

Gibbins²

1975

Can. J. Microbiol.

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“…With most (if not all) of these viruses enzymatic activities are associated that catalyze degradation reactions of the host capsular polysaccharides. So far, glycanases (hydrolysis of glycosidic linkages) (3,4,11,13,15,16,19,20) and esterases (hydrolysis of O-acetyl substituents) (18; B. Kwiatkowski, H. Beilharz, and S. Stirm, J. Gen. Virol., in press) have been recognized.…”

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confidence: 99%

Escherichia coli capsule bacteriophages. VIII. Fragments of bacteriophage 28-1

Rieger¹,

Freund-Mölbert²,

Stirm³

1976

J Virol

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As described previously, a host capsule depolymerase activity is associated with the particles of Escherichia coli capsule bacteriophage 28-1. This is a large virus with a long, contractile tail terminating in a base plate with spikes. In the present work, isolated virions were exposed to a variety of dissociative reagents and conditions. They were then tested for residual infectivity and depolymerase activity, as well as inspected under an electron microscope. Very mild acid treatment (10 to 15 min at pH 4.0 and 37 C) was found to cause a specific detachment of some phage spikes, together with a moderate drop in both infectivity and depolymerase activity. Large batches of viruses were fragmented in this manner, and the detached spikes were isolated. The host capsule depolymerase activity was found to be associated with these organelles. In negatively stained preparations, the spikes exhibited a length of approximately 18 nm and a thickness of about 5 nm. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis, they were found to contain polypeptides with molecular weights of 80,000 and 145, 000.

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