Nitrogen cycle Pseudomonas

Tabtoxin J is a dipeptide exotoxin produced by Pseudomonas tabaci, the organism responsible for the wildfire disease of tobacco plants [141]. When hydrolyzed by peptidase, in vivo, this exotoxin releases tabtoxinine-p-lactam K, which inhibits Glutamine synthetase of the photorespiratory nitrogen cycle, causing chlorosis and death of tobacco plants [142]. 

Nitrogen is returned to its atmospheric form by the action of denitrifying bacteria such as Pseudomonas thiobacillus and Micrococcus denitriflcans. The process is referred to as denitrification and represents the major mechanism of nitrogen loss in the overall nitrogen cycle whereby various forms of nitrogen in the soil revert to the N2 form. The reactions and their energetics are given below ... 

C34H3oFeN40io, Mr 710.48 uv , (tetramethyl ester) 660,611,570,532,446,422 nm. H. d belongs to the structural class of the isobacteriochlorins. Occurrence H. d, is one of the two prosthetic groups of cytochrorae cdp Cytochrome cdj, and thus also H. d, participates in the reduction of nitrite to NjO in chemoautotrophic bacteria such as Pseudomonas aeruginosa, Paracoccus denitriflcans, and Thiobacil-lus denitriflcans. H. dj is isolated from such denitri-ficating bacteria, which play an important role in the global nitrogen cycle. 

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