摘要:

Some 160 cultures were 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 survived well in soil but only moderately well under oil; soft‐rottingErwiniaspp. survived poorly but storage under oil was better than in soil; otherErwiniaspp. and mostCorynebacteriumspp. 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;Xanthomonasspp., 0·84 years. Estimated half lives forCorynebacteriumspp. 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 thePseudomonas‘syringae group’had a longer storage life when freeze dried by Greaves’method (h= 0·73) than when 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

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1965.tb02141.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Antigenic changes occurring on the surface ofBacillus cereusduring sporulation and germination have been followed, using fluorescent labelled antibodies.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1965.tb02142.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Commonly occurring contaminants of rotten eggs multiplied in a buffered solution of mineral salts containing intact shell membranes.Aeromonas liquefaciens, a nonpigmented pseudomonad, and sometimes a proteolytic strain of aCloacasp. caused the membranes to lose their pink colour. This was associated with a marked increase in the turbidity of the suspending medium and with the appearance of substances which reacted with Nessler's reagent and ninhydrin. These changes were not seen after growth ofProteus vulgaris, Alcaligenes faecalis, Pseudomonas fluorescensor non‐proteolytic strains ofCloacaspp. No differences were noted in the rate of penetration of the shell and shell membranes by these two group

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1965.tb02143.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Leifson's selenite F broth was more selective for salmonellae when incubated at 43° instead of the traditional 37°. Different selective agar media produced different numbers of colonies from similar inocula of salmonella cells, but Difco brilliant green agar consistently gave the highest recoveries when tested in this way. Combined with 43° selenite broth enrichment it provided a useful system for isolating salmonellae from foods. In a short comparative test this system compared favourably with more classical techniques employing enrichment of each sample at 37° in two different enrichment broths, followed by streaking on two selective ag

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1965.tb02144.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY