Oxytrichidae 131 



METHODS FOR CULTURING PLEUROTRICHA* 



Amos B. K. Penn, Tsing Hua University, Peiping, China 



Pleurotricha may be cultured in a hay-rye infusion with Colpidium as 

 food or in a physiological medium with Chlorogonium as food. For 

 experimental work, the latter method is preferred. 



A 0.2% hay and 0.2% rye infusion is prepared by boiling in a beaker 

 for 8 minutes 1 gm. of hay and 1 gm. of rye in 600 cc. of spring water. 

 After it has been boiled and cooled, there are about 500 cc. of solution. 

 Then half of the rye grains are removed, leaving the other half with all 

 the hay in the solution. This is then transferred to a battery jar of 1 liter 

 capacity and left for two days, in order to allow bacteria to grow. When 

 the infusion is 2 days old and contains many bacteria, it is inoculated 

 with Colpidium (or Chilomonas). After 24 hours, there are numerous 

 Colpidia present in the infusion. This is then inoculated with Pleuro- 

 tricha. From time to time rich cultures of Colpidia raised separately 

 [See also p. 51.] are added to the jar as additional food supply. 



When doing physiological work where bacteria and organic matter 

 are to be avoided, a physiological medium consisting of all inorganic 

 salts may be prepared according to the formula given below: 



CaCb 0.0008 N 



NaN03 0.0003 N 



MgSO.i 0.0002 N 



K0HPO4 0.0001 N 



KH2PO4 0.0001 N 



NH4NO3 0.0008 N 



In culturing Pleurotricha, Boveri dishes of 50 cm. capacity provided 

 with covers may be used. Place 20 cm. of this medium in each Boveri 

 dish. Add to each dish one pipette of concentrated culture of Chloro- 

 gonium, cultivated separately with the same medium. Then transfer 

 one or several pleurotrichs into each dish. Cover and place the cultures 

 in the bright part of the room. Pleurotrichs so cultivated are large and 

 uniform, morphologically and physiologically. They divide four times 

 a day. With this high rate of fission, a single individual may give rise 

 to several hundred individuals in a few days. 



References 



For the culture of Pleurotricha lanceolata see p. 107. 

 Family Euplotidae 



For the culture of Euplotes see p. 63. 



For the culture of Euplotes patella see p. 60. 



For the culture of other hypotrichs see p. 136. 



* See also Arch. j. Protist. Vol. 84, 1934, and Science 80:316, 1934. 



