242 



BACTERIA IN RELATION TO PLANT DISEASES. 



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Fig. 129.* 



Growth on cooked carrots looks yellowish at first. After some days there is a dis- 

 agreeable odor. On cooked radish there is a sharp odor in i to 2 weeks and the tissue is 

 then disorganized. The organism makes only a slight growth in Uschinsky's solution. 



The optimum temperature is about 32 C. Methylene blue (1 per cent) in bouillon 

 is reduced. Litmus is reduced. 



Nitrate is reduced to nitrite (tested with meta- 

 phenyldiamin, also sulphanilic acid + a-naphthylamin). 

 In young cultures in peptone-water or bouillon, 

 indol was detected in small quantity. In 10 days in 

 5 per cent peptone-water the cultures became so black 

 that indol could not be detected. Hydrogen sulphide 

 is produced. The organism was found in the earth of 

 a tobacco field to the depth of 3.5 decimeters. 



Uyeda has the following on enzymes. Invertase 

 is formed (the filtrate from a bouillon-culture passed 

 through a Chamberland bougie inverted saccharose 

 in one day). A very slight quantity of diastase appears 

 to be excreted. Cytase is believed to be produced. 

 Tyrosinase was detected in fresh agar-streak-cultures 

 and in bouillon-cultures by the addition of paraphenyl- 

 endendiamin and /3-naphthol (Spitzer's reagent). With this there developed a pale red 



stain soon becoming black. If one adds a 

 1 to 5 per cent solution of tyrosin to a cul- 

 ture of this bacillus the red-black color 

 increases more rapidly than without it. 

 Trypsin is also produced. This was 

 demonstrated in gelatin-cultures several 

 weeks old by adding some drops of 

 chlorine-water (Neumeister's tryptophan 

 reaction), the color changing to a red. In 

 the same way bromine gives a violet color. 

 The organism grew as well (luxuri- 

 antly) in an asparagin-dextrose solution 

 as in a peptone-dextrose solution. Bacil- 

 lus nicotianae did not grow in a mineral 

 solution (KH 2 P0 4 0.1, MgS0 4 0.03, NaCl 

 0.5 per cent) with dextrose or glycerin, 

 and the following nitrogen compounds in 

 1 per cent doses : Ammonium tartrate, po- 

 tassium nitrate, ammonium chloride. In 

 the same mineral solution with 1 or 2 per 

 cent asparagin and 1 per cent dextrose 

 there was a good growth and the forma- 

 tion of a pellicle when the medium was alkaline and no growth when it was acid. 



In the mineral solution with potassium nitrate and glycerin Bad. solanacearum devel- 

 oped normally, it is said. In the writer's experiments it developed feebly as compared with 

 the growth in bouillon. J The pigment formation is independent of magnesium salts. 



Fig. 130-t 



*Fig. i-'',. Rods of Bacillus nicotianae Uyeda, from a photomicrograph. X1200. (After Uyeda.) 

 fFlG. 130. Bat illus nicotianae Uyeda. from an agar-poured plate S days old. (After Uyeda.) 

 {Repeated in 1914 using Medan III with the same results. When inoculated thinly no growth; when inoculated 

 heavily a moderate growth with reduction of the nitrate. 



