Dalapon (2,2-Dichloropropionic acid) 
When dairy cows were fed dalapon, less than 1% of the ingested 
dose appeared as residues in the milk, mainly as unchanged dalapon but 
with traces of dalapon glycerides (Kutschinski, 1961). 
Tracer studies with da lapon-2-c14 and 136 showed that dalapon was 
absorbed, translocated, and accumulated in higher plants as the original 
molecule or dissociable salt and might remain non-metabolized for long 
periods (Blanchard et al., 1960; Foy, 1959a, b, 196la, b, c, 1962a; 
Andersen et al., 1962a; Leaure, 1962). A small amount of decomposition occur- 
red slowly and resulted in release of 136 or incorporation of ae into 
other compounds. Tests with tissue homogenates did not indicate 
metabolic incorporation of dalapon into insoluble macromolecules. Some 
indication of dehalogenation was indicated on chromatograms (Foy, 1959b, 
1961c). Propionic acid, which could arise through such reactions, 
competes with B-alanine in pantothenic acid synthesis. Studies have 
shown that dalapon does, in fact, inhibit pantothenate synthesis (Hilton 
et al., 1959). 
Labeled dalapon was metabolized by some species of microorganisms 
(Jensen, 1957; Hirsch and Alexander, 1960; Reid, 1960). Five new c136- 
labeled compounds were found, of which two were identified as inorganic 
136 and monoch loropropionate-C1?° (Foy, 1959b, 196lb,c). Using 
Arthrobacter sp., labeled dalapon gave rise to pyruvate (Kearney et al., 
1964). In other studies, eight bacteria isolated from soil were capable of 
decomposing dalapon. Six were tentatively classified as agrobacteria and 
two as pseudomonas (Magee and Colmer, 1959). 
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