316 Marine Microbiology 



five feet of coiled twine were placed in 500 ml Erlenmeyer 

 flasks, each containing 100 ml of O.lf^ yeast extract (Difco) and 

 0.1% Tris ( Trishydrox)Tnethylaminomethane ) buffer in sea water. 

 The pH of the medium after autoclaving was 6.5 to 7.0. The 

 same medium without Tris showed a pH of 4.5. In earlier work, 

 the pH of the Manila yeast extract medium was adjusted fol- 

 lowing autoclaving by addition of pre-calibrated amounts of 

 sterile NaOH. However, a decrease in pH of the solution re- 

 sulted upon standing, often within twenty-four hours after the 

 addition of the NaOH. A drop in pH also occurred in the flasks 

 containing Tris, although this was in general a slower process, 

 permitting spore germination and initial development of the 

 fungus. Growth usually caused a rise in the pH of the medium. 



The Manila used throughout these studies was 100 per cent 

 grade F, non-Davao (Tagaon) twine, supplied by Dr. Bryce 

 Prindle, formerly of the Plymouth Cordage Co., Plymouth, Massa- 

 chusetts. The effectiveness of Manila cordage as a substrate for 

 growth activities of marine fungi has been discussed in earlier 

 work. 



The terms "Manila," "cordage," and "twine" are used inter- 

 changeably in this paper and refer to the intact twisted material. 

 The term "fiber" is used to indicate single macroscopic constit- 

 uent units of the cordage. 



Different patterns of infestation of the twine were developed 

 by regulating the arrangement of the material in the culture 

 vessels. In one series of flasks, the cordage was completely sub- 

 merged, whereas another series was arranged so that only the 

 middle four to six inches of each eighteen to twenty inches length 

 of cordage was actually immersed in the liquid medium. The 

 latter arrangement was used to concentrate maximum fungal 

 growth and reproduction in the central region of the twine, so 

 that this area could be placed between the two grips of the 

 testing machine. This permitted a more definitive evaluation of 

 the effect of the fungus on the cordage itself. Placement of the 

 cordage in the flask whereby only a portion was subject to fungal 

 attack was accomplished by forming the lengths of cordage in 

 each vessel into a tight "U" with the area of the outer ends twisted 

 and wrapped in aluminum foil. Although three to four inches 



