FAMILY CYTOPHAGACEAE 



1015 



9. Cytophaga diffluens Stanier. (Jour. 

 Bact., 40, 1940, 623; Jour. Bact., 42, 

 1941,546.) 



Etymology : Latin diffluens, spreading, 

 flowing away. 



Pointed, sometimes spindle-shaped, 

 flexible rods, 0.5 to 1.5 by 4 to 10 microns. 

 In old cultures involution forms consist- 

 ing of long, twisted, thin threads are 

 found. Star-shaped aggregates of cells 

 occur in liquid media. Creeping motility 

 on solid surfaces, non -motile in liquids. 



Growth on a sea water-peptone agar 

 plate begins as a thin, pink, rapidly 

 spreading swarm which often covers the 

 entire surface in a few days. The swarm 

 gradually increases in thickness and 

 develops an irregular, beaten-copper 

 surface due to the liquefaction of the 

 underlying agar. After 4 to 5 days the 

 color becomes orange. Liquefaction of 

 the agar is ultimately almost complete. 



Sea water-gelatin stab : Rapid lique- 

 faction. 



Growth in liquid media is turbid, often 

 with suspended floccules and a heavy 

 pellicle. 



Xylose, glucose, galactose, lactose, 

 maltose, cellobiose, cellulose, agar and 

 alginic acid are utilized, but not arabinose, 

 sucrose, chitin or starch. 



Yeast extract and peptone are the only 

 suitable nitrogen sources known. 



Weakly catalase positive. 



Indole not formed. 



Nitrites produced from nitrates. 



Hydrogen sulfide not produced. 



Salt concentration range: 1.5 tc^ 5.0 

 per cent. 



Slightly aerobic. 



Optimum temperature 22° to 25°C. 



Source : Isolated from sea water. 



Habitat : Sea water. Probably on 

 decaying marine vegetation. 



10. Cytophaga sensitiva Humm. 

 (Duke Univ. Marine Lab., Xorth Caro- 

 lina, Bull. 3, 1946, 64.) Etyomology: 

 Latin sensus, to perceive. 



Cells long, slender, flexous rods. 



Apparently not flagellated, 0.8 to 1.0 

 by 7.0 to 20 microns. Cell ends not 

 tapered or only slightly so. Gram- 

 negative. Cells e.xhibit creeping motil- 

 ity on agar with ability to reverse 

 direction of movement without turning. 

 Bending movements occur in liquid 

 media. 



Colonies light orange, thin and shin- 

 ing. Irregular margin. Outer pari 

 composed of a single layer of cells, 

 spreading rapidly, the center somewhat 

 thicker and more or less opaque, sunken 

 in the agar. Agar liquefied. Single 

 colony may nearly cover the surface 

 of the agar in the Petri dish within one 

 week; center of colony sinks to the bot- 

 tom of the dish and may develop vertical 

 sides. Usually the colony begins to die 

 after a week or ten days from the center 

 outward, as shown by loss of pigment. 

 Apparentlj^ no water-soluble pigment is 

 produced. Colony 18 mm in diameter 

 and gelase field 25 mm in diameter after 

 three daj's on agar containing 0.8 per 

 cent potassium nitrate and 0.8 per cent 

 peptone (iodine stain). 



Gelatin: Xo growth. 



Milk: Xo growht. 



Xitrate apparently not produced from 

 nitrate (agar medium). 



Optimum nitrate concentration of 

 medium appeared to be 0.5 per cent. 

 Fair growth on sea water plus agar onh^, 

 and on agar containing 1.0 per cent 

 potassium nitrate. Slight growth on 

 2.0 per cent nitrate agar. 



Optimum peptone concentration ap- 

 peared to be about 0.1 per cent; growth 

 inhibited by concentrations of peptone 

 exceeding 0.4 per cent. 



Xo growth on agar media containing 

 any one of the following substances in a 

 concentration of 0.2 per cent glucose, 

 starch, ammonium sulfate. The basal 

 medium, however, supported excellent 

 growth. 



Repeated efforts were made to obtain a 

 pure culture by streaking plates and by 

 pouring plates. These were finally sue- 



