ASPERGILLUS NIGER GROUP 239 



Mildew: Strains of A. niger represent a common cause of mildew on ex- 

 posed wood surfaces and cotton fabrics. Partansky and McPherson 

 (1940) used a strain of this species successfully for testing the mold- 

 resistant properties of oil paints. Aspergillus niger is commonly included 

 in the mixtures of miscellaneous molds used for testing the effectiveness 

 of mildew- and rot-proofing agents when impregnated in textiles and fabrics. 

 Where pure cultures are employed, species of Chaetomium and Metarrhizium 

 are generally used. 



Mold Physiology 



Members of the Aspergillus niger group have been used extensively in 

 investigations on mold physiology, probably more than any other form. 

 As early as 1909 Latham studied nitrogen assimilation by A. niger (S. 

 nigra) to be followed in 1911 by Dox studying phosphorus assimilation by 

 the same species. Beginning in 1918 and continuing up to the present 

 time, Steinberg has published a succession of papers on the physiology of A . 

 niger, with special reference to the role of heavy metals in its nutrition. 

 A single strain of A. niger which is carried in the NRRL collection as No. 334 

 (Thorn No. 4247) has been used throughout these investigations. Studies 

 of a somewhat similar character have been conducted by Bortels (1927), 

 Levy (1932), Gollmick (1936), and others. Citation of these papers, to- 

 gether with many additional references are presented in the Topical 

 Bibliography under the subtitle "Physiology". An attempt has been 

 made to present sufficient references to serve as a point of entrance to the 

 literature of the field. 



Pathogenesis 



Members of the Aspergillus niger group are commonly isolated from 

 the external ear of man, this being the source of the classic Sterigmatocystis 

 antacustica of Cramer. Other species reported to have been isolated from 

 cases of otomycosis include A. niger van Tieghem, A. phoenicis (Cda.) Thorn 

 and Church (with long primary sterigmata), A. giganteus (Mattlet) Dodge, 

 and A. Macfiei Dodge. A. Macfiei showed no signs of pathogenicity 

 when tested on experimental animals. There is no morphology to dis- 

 tinguish either of the latter two forms from the ubiquitous saprophytic 

 types, and it appears probable that many strains can become established 

 in the auditory canal under certain favorable and probably temporary 

 conditions. 



Once entrenched in the flesh about the auditory canal, the mycelium has 

 been found to be very persistent. One case is known in which occasional 

 abscesses have occurred over a period of 25 years during which desultory 

 treatment has quieted the inflammation but has not destroyed the parasite. 



