ECOLOGICAL STUDIES ON TILE SYMBIOSIS OF TER ITOMYCES ...

depth was the same for all plates as there Is controversy as to the
Influence of the depth of the medium on radial growth (Brancato and
Golding 19539 Chaudhuri 1923 and Trinci 1969)e Plugs of Termitomycess
approximately 5m In diameter, were cut from just Inside the edge of
actively growing cultures with a sterile cork borer, and placed
centrally on the plates of medium* Two measurements of the diameter
of the colonies were then taken at right angles to each otherg and
this was repeated on several occasions over the 2 week course of the
experiment. After 2 weeks the final measurements were taken and the
form of growth of TeraitgýLcea noted* Incubation was at 290C*
In addition to fungal contamination, bacterial contamination of
isolations was also a problem, Four antibacterial antibiotics and
rose bengal were tested for their effect on the radial growth of
, Tqrmit2=ces@ Novoblocin was dissolved In sterile water at the rate
of 0.1 g In 10 ml and then added to the medium prior to autoclavinge
chloramphenicol was dissolved in 10 ml of 95% alcohol and added to
the medium prior to autoclaving, Streptomycin sulphate and penicillin
sodium salt were added to the medium after autoclaving a! s those lose
their activity If autoclaved,
To prevent growth of and contamination by other fungi a total of
33 different substances were tested* Substances which Inhibit the
growth of undesired fungi were tested as well as substances which
selectively enhanced the medium isee provided in the medium an energy
source or other nutrients which are assimilabla only by a limited
number of micro-organisms. The term selective medium Is here meant
to Include any medium which achieves selective ex lusion of undesired
organim=9 whether by selective Inhibition or selective enhancement
(Tsao 1970).
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