Pathways of Lower Alkaline Oxidation 473 



the medium and this observation is possibly correlated with the 

 fact that these substrates are oxidized through a different path- 

 way. 



Concerning the role of pyocyanin as electron acceptor and 

 carrier for tlie hydrocarbon dehydrogenases in F. aeruginosa, it 

 was observed previously by Ramakrishnan and Cambell (6) 

 that this natural pigment is a very active electron acceptor for 

 the gluconic dehydrogenase of the same organism. Unpub- 

 lished experiments recently made in our laboratory have given 

 prehminary evidence that pyocyanin takes place in the physio- 

 logical electron transfer between DPNH and cytochrome c, as 

 demonstrated by the fact that pyocyanin increases the activity 

 of DPNH-cytochrome c reductase in sub-cellular particles. 



ADDENDUM 



Since this contribution was presented, the anaerobic for- 

 mation of n-1 heptene from n-heptane has been demonstrated by 

 infra red spectrophotometry, in collaboration with Dr. J. Chou- 

 teau. Details of this work have been published elsewhere. (Na- 

 ture, London, 194:576, 1962). 



SUMMARY 



Experimental evidence obtained by the simultaneous adap- 

 tations metliod show that Psetidomonas aeruginosa oxidizes the 

 lower ( Cg to Cio ) paraffins through an adaptive pathway involv- 

 ing successive formation of the corresponding mono-alcohol, 

 aldehyde and fatty acid, and then proceeding further by a P- 

 oxidation mechanism. 



Cell-free preparations obtained from cells grown on n-hep- 

 tane contain DPN dependent dehydrogenases for the corres- 

 ponding alkane, mono-alcohol and aldehyde. These dehydro- 

 genases are equally active with the natural pigment pyocyanin 

 as the electron acceptor. 



REFERENCES 



1. AzouLAY, E. and Senez, J. C: Degradation bactciienne des hydio- 

 carbures paraffiniques. 2. Determination des produits intermediaires 

 par la mcthode des adaptations simultanees. Ann. Inst. Pasteur, 98: 

 868, 1960. 



