The Physiological and Serological Characters of Freeze-dried Lactobacilli

Abstract

SUMMARY: A comparison of physiological and serological characters of 41 strains of lactobacilli before freeze-drying and after freeze-drying and storage for 6 months showed that freeze-drying did not materially alter these characters.If there were some degree of selection, or the loss of some enzyme, antigen or other characteristic of organisms during the process of freeze-drying, strains with properties differing from the original would result. Before freeze-drying a collection of strains of lactobacilli (Briggs, Tull, Newland & Briggs, 1955) it was therefore necessary to determine whether freeze-drying did in fact alter the physiological and serological chaTacters of the organisms dried. Elser, Thomas & Steffen (1935) freeze-dried strains of meningococci and gonococci and found them to be unaffected, and Cowan (1951,1954) found that cultures examined by biochemical tests before and after they were dried showed no significant differences. Several authors have also reported the retention of serological properties (Stamp, 1947 The physiological and serological properties of the strains of lactobacilli used for the present work had been examined before freeze-drying by Briggs (1953), Wheater (1955 a, b) and Sharpe (1955). This paper reports a comparison of the results of these tests on organisms before freeze-drying and after freezedrying and storage for 6 months. An account of the results of freeze-drying 12 lactobacillus antisera is also included. METHODS Strains.The 41 strains which were tested were representative of all groups and sections described by Briggs (1953). Cultures were dried by Briggs et al. (1955), who also tested the rates of survival. Tubes were opened after 6 months storage and subcultured into tomato glucose broth (Briggs, 1953). Four further daily sub-cultures were made and strains were then tested by the methods given below. Physiologica2 testsThe media and methods used for the following tests were those of Briggs (1953) : production of gas from glucose, gas from citrate and ammonia from arginine ; heat survival ; growth temperatures ; tolerance of NaC1. Carbohydrate fermentation tests (Wheater, 1955a) were done on a few of the strains. Where

Outermost-cell-surface changes in an encapsulated strain of Staphylococcus aureus after preservation by freeze-drying

“…We have already reported that CSP is inhibited by hightemperature cultivation (13) or the addition of bile acid derivative (12,20). Loss of CSP because of freeze-drying is an important issue because it affects the maintenance of morphological stability during the preservation of microorganisms (1,8,26,29). The biological significance of capsule or slime has attracted attention in various fields recently (3,4,7).…”