Studies on the Fire-Blight Organism, Bacillus amylovorus 23 



digest starch, or if it does the process is very slow. D. II. Jones 

 (1909:60) found diastasic action on starch jelly after three days at 

 25° C, but Stewart (1913 : 330) was unable to substantiate Jones' claim. 



Inulase 



In the test for inulase, Uschinsky's solution was prepared using 1 per 

 cent of glycerin. A portion of the solution was inoculated, was incu- 

 bated for fifteen days, and showed no reducing action on Fehling's solu- 

 tion. To the remainder of the solution 1 per cent of inulin was added, 

 and three flasks containing 40 cubic centimeters each were used for 

 each check and culture. All the flasks were incubated for eleven days 

 at 25° C. Since inulin does not reduce Fehling's solution, levulose 

 present in the culture medium would show the decomposition of inulin. 

 The following results were obtained on testing for sugars : 



Culture 40 cc, no toluol, 25.9 milligrams of sugar 



Culture 40 cc, toluol added two days after inoculation, 10.5 milligrams of sugar 

 Check 40 cc, no toluol, 7.2 milligrams of sugar 



Check 40 cc, toluol added two days after cultures were inoculated 7.5 milli- 

 grams of sugar 



Approximately three times as much Cu 2 was precipitated from the 

 Fehling's solution by the culture as by the checks. While the total 

 amount of sugar released from inulin is small, it is nevertheless signifi- 

 cant. At the time when the tests were made, the precipitate in the 

 checks was just sufficient to be detected by the eye. The precipitate in 

 the cultures was positive, and appeared to be greater than subsequent 

 weighings showed. The writer is convinced that Bacillus amylovorus 

 can split inulin, and, if this is accepted, then it may be inferred that 

 inulase is secreted, unless the splitting of inulin is attributed to the 

 presence of sucrase. 



Pectinase . 



The enzyme pectinase is often considered as a group of three distinct 

 enzymes: pectosinase, pectase, and pectinase. According to Atkins 

 (1916), pectosinase is the enzyme which converts the pectic compounds 

 of the middle lamella into soluble pectin; pectase coagulates pectin ; and 

 pectinase hydrolyzes pectin to reducing sugars of the pentose series. 

 Not all authors agree on the preceding classification ; some believe there 

 is but one enzyme acting on pectic compounds. However, for the sake 

 of clarity, the writer will use Atkins' terminology. 



Stewart (1913 : 360) failed to find evidence of any cell wall dissolving 

 enzymes secreted by Bacillus amylovorus. Nixon (1927) found that 

 when B. amylovorus was migrating in the host tissue as zoogloea, there 

 was little or no dissolution of lamellae or cell walls; but when the bacilli 



