NUTRITION OF MICRO-ORGANISMS 



synthesised the thiazole half. Like M. Ramannianus, Rhodotorula rubra 

 cannot grow in the absence of aneurine but the two moulds together 

 will grow and develop satisfactorily in an aneurine-free medium, 

 because the former is able to synthesise the pyrimidine half of the 

 molecule, which the latter cannot synthesise, whereas the latter can 

 synthesise the thiazole half, which the former cannot synthesise. The 

 behaviour of these two moulds is a striking example of symbiosis, 

 and is due to the ability of each partner to supply a nutrient that 

 the other needs. Another illustration is provided by the phenomenon, 

 well-known tp horticulturists, that orchid seeds will only germinate 

 when a mycorrhizal fungus is present. It is now known that the 

 latter S5mthesises aneurine, which the seeds require. 



An increase in the amount of glucose consumed by Melanospora 

 destruens or Phycomyces nitens occurred on addition of aneurine to 

 the mediimi,2o owing to the increased rate of respiration. Phytoph- 

 thora infestans also required aneurine for growth and this could not 

 be replaced by a mixture of the two halves of the molecule. ^^ 



Aneurine is also necessary for the growth of Ustilago violacea, and 

 U. scahiosae, but not of other species of Ustilago. '^'^ It is also necessary 

 for the growth of the wood-destroying fungi, Stercum frustulosum, 

 Hydnum erinaceus, Polyporus Spraguei and Fomes igniarius,^^ of a 

 number of other wood-destrojdng Polyporiaceae,^^ and of Lophiodermum 

 pinastri, Sclerotinia cinerea, Helvella infesta, Polyporus adustus, P. 

 ahietinus, Fomes pinicola, Trametes cinnabarina, T. serialis, Lenzites 

 sepiaria and Tricholoma nudum. "^^ 



Other moulds for which aneurine is a growth factor were reported 

 by P. R. Burkholder and D. Moyer ; ^s of seventeen fungi tested, the 

 following required aneurine : Hormodendron pedrosoi, Phialophora 

 verrucosa, Sporotrichon schencki, Trichopyton faviforme, T. sulphureum, 

 T. violaceum, Fomes annosus, Coryne sarcoides, Cytospora sp., and 

 Lenzites betulina. W. H. Schopfer and S. Blimier ^7 reported that 

 aneurine was necessary for the growth of Trichophyton album, but 

 could be replaced by an equimolecular mixture of the thiazole and 

 pyrimidine halves ; either alone was without effect. 



According to N. Fries, ^^ pyridoxine is essential for several species 

 of Ophiostoma (Ceratostomella). Some of them, including 0. multi- 

 annulatum and 0. pluriannulatum, required aneurine in addition, 

 whilst the growth of 0. ulmi was stimulated by the addition of aneurine. 

 Ascoidea rubescens required pyridoxine, aneurine and biotin. Aneurine 

 was an essential growth factor for 0. coeruleum, 0. quercus, 0. piceae, 

 0. stenoceras, 0. pini and for Mitrula pusilla. These species were 

 apparently capable of synthesising the thiazole moiety but not the 

 pyrimidine half of the molecule. W. Schopfer ^^ also observed that 

 Ceratostomella ulmi could grow without added aneurine, but not in the 



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