Lyophilization of Pasteurella pestis1

Heckly, Robert J.; Anderson, A. W.; Rockenmacher, Morris

doi:10.1128/aem.6.4.255-261.1958

Cited by 15 publications

(3 citation statements)

References 8 publications

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“…Again there is little evidence that the species in the Pseudomonas syringae group are other than different pathogenic forms of a single species. The assumption that survival of the freeze drying process and survival in subsequent storage are correlated is implicit in many reports on the subject but its general validity was not confirmed by Fry & Greaves (1951) or Steel & Ross (1963) nor is it supported by the data of Heckley, Anderson & Rockenmacher (1958), which showed that similar proportions of cells of Past. pestis survived freeze drying whether the menstruum contained glucose, sucrose or lactose, but that subsequent survival in storage was markedly poorer in preparations containing glucose than in those containing sucrose or lactose.…”

Section: Discussionmentioning

confidence: 98%

The Preservation of Plant Pathogenic Bacteria

Lelliott¹

1965

J Appl Microbiol

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Some 160 cultures wcre preserved by freeze drying, under mineral oil and in soil. After storage for 5 years all freeze dried cultures were viable; most cultures of xanthomonads were viable under oil and in soil; pseudomonads snrvived well in soil but only moderately well under oil; soft-rotting Eruinia spp. survived poorly but storage under oil was better than in soil; other Erwinia spp. and most Corynebacterium spp.survived well in soil and under oil. The mean half lives in years (h) calculated for freeze dried cultures of groups of closely related bacteria were : Erwinia 'chrysanthemi group', 0.40; Erwinia 'carotovora group', 0.51 : Pseudomonas 'syringae group', 0.50; Xanthoinonas spp., 0 4 4 years. Estimated half lives for Corynebacterium spp. ranged from 1.8 to 6.5 years. There was no evidence that bacteria which had been in culture for more than 3 years before being freeze dried had a longer storage life than those freeze dried within 3 years of isolation. Cultures of the Pseudomonas 'syringae group' had a longer storage life when freeze dried by Greaves' method (h=0.73) than whcn freeze dried by Annear's method (h = 0.50). There appeared to be no general correlation between half life in storage and either the proportion of cells surviving the freeze drying process or the viable cell count immediately after freeze drying. Most of the variation in the results could be attributed to variation in viable cell count between different ampoules of the same batch of a culture.

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Section: Discussionmentioning

confidence: 98%

The Preservation of Plant Pathogenic Bacteria

Lelliott¹

1965

J Appl Microbiol

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“…Lyophilization. The apparatus and techniques were described in detail previously (4). Equal volumes of a second-passage culture and 6% lactose were mixed, and 12 ml of the mixture was dispensed into 60-ml glass ampoules.…”

Section: Methodsmentioning

confidence: 99%

Virulence and viability of Yersinia pestis 25 years after lyophilization

Heckly¹,

Blank²

1980

Appl Environ Microbiol

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When equal volumes of 6% lactose and a broth culture of Yersinia pestis were mixed before freezing, approximately 50% of the cells survived lyophilization and reconstitution on the following day. Concomitantly, the number of viable cells per 50% lethal dose increased from about 16 to 125 organisms. On subsequent storage of the lyophilized cells under vacuum in glass ampoules at 4 degrees C for 25 years, more than 25% of the cells remained viable. When stored cultures were assayed immediately after reconstitution, virulence for mice was significantly reduced (as many as 4,000 cells/50% lethal dose), but the virulence was fully restored when reconstituted cultures were held for 24 h at room temperature, or when a subculture was prepared in fresh medium.

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“…The cell suspensions were frozen by agitating the ampoules in a dry ice-ethylene glycolmonoethyl ether bath (freezing rate, approximately 100 C/min). Ampoules containing the frozen cell suspensions and still immersed in the freezing bath were then attached to a 30-port manifold connected in series by using amber latex tubing to a -79 C (dry ice-ethylene glycol-monoethyl ether) condenser and a vacuum pump as described by Heckly (5). After a vacuum of 50 Mm of Hg or less was attained (as determined with a McLeod gauge, Stokes Machine Co., Philadelphia, Pa.), the dry ice was allowed to sublime, and the bath was permitted to reach room temperature at an uncontrolled rate (during a period of approximately 3 hr).…”

Section: Materils and Methodsmentioning

confidence: 99%