384 A MANUAL OF THE PENICILLIA 



ing. Harrison (1934) noted its presence in hay undergoing thermogenic 

 spoilage although the optimum temperature of the species was listed as 

 25°C. Peele and Beale (1940) reported P. oxalicum and Fusarium monili- 

 forme to promote aggregation and granulation in Cecil clay loam soil. The 

 inoculation of non-sterile soil containing sucrose or ground oat straw re- 

 sulted in greater aggregation than in uninoculated controls. Similar treat- 

 ments in field plots increased granulation and decreased run-off and erosion. 



PenicilUum oxalicum usually exists in nature as a true saprophyte. 

 Nevertheless, it is capable of becoming parasitic under certain conditions. 

 As shown by Johann (1928 and 1929), Koehler and Holbert (1930), and 

 Johann, Holbert, and Dickson (1931), it sometimes causes serious infections 

 of corn seedlings, being especially destructive of certain inbred strains. 

 Johann, et at. (1931) observed that the fungus damaged or killed the seed- 

 lings indirectly rather than by direct invasion of healthy cells, and suggested 

 that sufficient oxalic acid might be produced to kill cells in advance of the 

 fungus. The fungus commonly develops on the ear at the base of the 

 kernels in immature or improperly dried seed corn, hence furnishes a ready 

 source of infection when planted. 



Diachun (1939) found PenicilUum notatum and PenicilUum sp., isolated 

 from a corn ear in the field, to afford partial protection against infection by 

 P. oxalicum, but no antagonism between the strains was observed in culture. 

 A substance toxic to corn seedlings was produced by P. oxalicum when 

 grown on Richard's solution and on autoclaved or living corn kernels. Ho 

 (1944) reported P. oxalicum as a moderately destructive soil fungus attack- 

 ing the roots of maize. Leukel and Martin (1943) reported P. oxalicum as 

 one of the more important fungi producing seedling blight in sorghum. It 

 was likewise highly destructive of kernels which sustained seed coat injuries 

 during threshing. 



Kirsh (1935a) obtained from Penicilliufn oxalicum and Aspergillus flavus 

 a water soluble enzyme, or lipase, capable of hydrolyzing olive oil. Maxi- 

 mum production was realized on a bran-soybean medium at 28°C. at the 

 time of greatest sporulation. A preparation was secured which contained 

 8.5 times more lipase per unit of protease than did a commercial "high- 

 lipase trypsin". Investigating the properties of the lipase further, Kirsh 

 (1935b) found its optimum pH to be 5.0 and its optimum temperature 

 37-40°C. Activity was rapidly lost upon storage, and complete inactiva- 

 tion occurred in one hour at 60 °C. The lipase was non-specific, hydrolyz- 

 ing corn, cottonseed, cod liver, and sesame oils to the same extent as olive 

 oil. 



Currie and Thom (1915) described PenicilUum oxalicum as producing 

 oxalic acid in excess of other organisms tried. When calcium carbonate 

 was added to the media the mold grew poorly but the yield of acid was 



