Filamentous Form of Bacteriophage at the EarHest Stages of 

 Their Formation in a Bacterial Cell 



A. S. TiKHONENKO and A. E. Kriss 



Laboratory of Electron Microscopy, U.S.S.R. Academy of Sciences, Moscow 



Our examinations(6) of the fine structure of particles 

 of various phages led us to a conclusion that the 

 typical spermatozoon-like figure of the bacterio- 

 phage is formed by a chain of roundish elements 

 twisted in the shape of spiral or clew. The twisted 

 part of this chain looks like the head of phages and 

 the free end of the chain like the tail (hg. 1). In the 

 literature a number of authors (1, 2, 3, 5, 10) have 

 published electron micrographs confirming this idea. 

 It is interesting that in the bacteriophage of 

 Bacillus mycoides we (7) succeeded, with the aid of 

 hydrostatic pressure of several thousands of atmos- 

 pheres, in untwisting the chain of globules forming 

 a phage particle. In bacteriophage specimens which 

 were subjected to high pressures from several hours 

 to several days, filaments of different length appear 

 (fig. 2), which proved to be linear chains of globular 

 formations (fig. 3). 



Fig. I. Spiral shape of the heads of phage particles of Bcu . 

 mycoides. 



Fig. 2. Different degree of untwisting of the filament that 

 forms a phage particle of Bcu. mycoides under the influence 

 of hydrostatic pressure of 5000 atm. during 2\, 4, 20 and 

 48 hours. 



These filamentous structures are found at the 

 earliest stages of formation of phage particles (4, 8). 

 This may be seen for instance when studying lysis 

 directly on the grid covered with a parlodion film 

 according to a method by Pocotinsky and others (9) 

 and modified by us. 



After lysis the phage particles frequently lie in 

 accumulations whose dimensions and form remind 

 of a bacterial cell. The whole field of vision is occupied 

 by roundish particles which have a spiral, and more 

 seldom ring shape, and sometimes by straight fila- 

 mentous structures. 



In fig. 4 besides particles of spiral shape it is 

 possible to see fibrous structures which in one case 

 are the continuation of the head spiral and in an- 

 other cases position themselves between the heads of 

 separate phage particles (shown by pointer). It is 

 probable that in the latent period fibrous material 

 is formed in the bacteria from which the phage 

 particles develop. 



As a confirmation of this assumption may serve 

 the pictures observed in some specimens of lysed 

 bacterial cells. Together with accumulations of phage 

 particles in these specimens were found fields of 

 vision completely filled with fibrous formations 

 (fig. 5) which in some places were separated and in 

 other places fitted closely to each other. 



Probably, twisting the filamentous material in the 

 lysed bacterial cell forms the heads of phage par- 

 ticles. In the cases when the filament is twisted 

 freely, the heads of phage particles look like rings 



Fig. 3. The filamentous structures consisting of roundish 

 elements in the phagolysatc of Sac. mycoides after being 

 influenced by hydrostatic pressure of 5000 atm. during 48 

 hours. 



Fig. 4. The filamentous structures which are the continua- 

 ation of the head spiral and freely lie between the phage parti- 

 cles oi Bac. mycoides (shown by pointer). 



Fig. 5. Accumulation of filamentous structures at the place 

 of bacterial lysis of Bac. mycoides. 



