ACTINOPLANACEAE 



311 



into irregular pieces of hyphae, rods and 

 coccoid bodies. 



Aerobic, gram-positive, and acid-fast. 



Occur saprophytically in soils and infresh 

 water, and are world-wide in distribution. 

 Over L20 cultures were isolated. 



The genus Actinoplanes is readily dis- 

 tinguished from Streptosporangium. On 

 leaves, the latter produces a conspicuous 

 aerial mycelium which resembles that in 

 most species of Streptomyces, whereas no 

 such mycelium is usually found in Actino- 

 planes. The isolates of the latter grow much 

 more vigorously on agar than do those of 

 Streptosporangium. due most striking dif- 

 ference is that in Actinoplanes the sporangio- 

 spores are motile, whereas in Streptosporan- 

 gium they are nonmotile. 



Under certain conditions of culture, some 

 species of Actinoplanes resemble Micro- 

 monospora. A nonsporangial strain of Ac- 

 tinoplanes might easily be confused with 

 certain micromonosporas. The spores of 

 Micromonospora, however, are formed singly 

 or in grape-like clusters hut never in chains, 

 whereas in Actinoplanes they are formed 



< 



§ 



Figure 63. Actinoplanes (Prepared by H. 

 Lechevalier, Institute of Microbiology). 



singly and also in chains but not in grape- 

 like clusters. In most species of Micromono- 

 spora, on certain agars, the sporulating 

 surface t urns black, whereas this change does 

 noi occur in Actinoplanes. In general, the 

 species of Micromonospora are less vigorous 

 in growth than those of Actinoplanes. 



Several species of Actinoplanes, when 

 grown on potato-glucose and certain other 

 agars, will form a small pasty culture which, 

 when mounted and crushed under a cover- 

 slip, breaks up into minute spheres, irregular 

 rods, and short, branched, hyphal segments, 

 much as in Nocardia. Such growth, however, 

 is not the normal condition for any species 

 of Actinoplanes. None of the 25 species 

 of Nocardia examined by Couch formed 

 sporangia when grown either on any of the 

 agars most favorable for sporangia] forma- 

 tion or on Paspalum leaves in water. 



Gaertner (1955) isolated cultures of Ac- 

 tinoplanes from soil and found them capable 

 of decomposing keratin. 



The type species is Actinoplanes philip- 

 pinensis Couch. 



Actinoplanes philippinensis Couch, 1950 

 (Couch, J. X. J. Elisha Mitchell Sci. Soc. 

 66, 87, 1950). 



Morphology: Produces a very dedicate, 

 hyaline to pinkish-buff internal mycelium 

 and an inconspicuous external fringe of 

 threads around the entire edge of the leaf of 

 sterile Paspalum grass in water. Sometimes a 

 compact mound or tufts of hyphae are 

 scattered over the top surface, giving the 

 leaf a speckled or finely powdered appear- 

 ance. Hyphae are 0.5 to 1.5 m thick, 

 branched, sparingly septate. Sporangia, 

 usually formed abundantly on grass after 

 about 10 days, on long unbranched stalks, 

 mostly spherical when mature, S.4 to 22 fi. 

 Spores arranged, at maturity, in coils or 

 irregularly in the sporangium, about 1 to 

 1.2 /J. They are discharged through a pore 

 or by the partial dissolution of the sporangia] 

 wall, and swim vigorously. 



