370 A MANUAL OF THE PENICILLIA 



Of the above cultures, NRRL 824 (figs. 97C and 98A) is of the greatest 

 interest since it was from this strain that Fleming discovered the antibiotic 

 penicillin (1929), and it was this culture which was employed in all of the 

 early studies on the production and evaluation of this drug. NRRL 832 is 

 likewise of special interest since this strain was the first to be successfully 

 used in the production of penicillin by submerged culture techniques 

 (Moyer and Coghill, 1946b). NRRL 821, Westling's type, produces very 

 low yields of penicillin under all conditions examined. 



Penidllium notatum Westling represents a variable species which may 

 appear in a number of fairly distinct cultural forms. When examined 

 apart from a multitude of other forms (which tend to minimize the im- 

 portance of the criteria that have to be used for separation) some of these 

 might seem to warrant specific or varietal recognition. When, however, 

 large numbers of strains are examined, the significance of such strain varia- 

 tions largely disappears. We believe it prudent to consider all of them 

 within the framework of the single species P. notatum. The following 

 strains may be cited as representative of some of the more pronounced 

 cultural types encountered: 



NRRL 832 (figs. 97E and 98C), cited above, is marked by restricted 

 but otherwise typical colonies; penicilli usually consist of a single verticil 

 of 3 to 5 metulae and are more compact than most ; and conidia range from 

 subglobose to definitely elliptical. The strain is regarded as somewhat 

 transitional toward Penicillium chrysogenmn Thom. Certain cultural 

 variants (Raper and Alexander, 1945) derived from this strain are of par- 

 ticular interest in that they develop a pronounced vegetative mycelium 

 which is pink to red in color (near daphne red, R., PI. XXXVIII) and is 

 suspected of being an accentuation of the red or rosy factor reported 

 by Dierckx as characterizing P. citreo-roseum and P. griseo-roseum 



(Col. PL I). 



NRRL 1950 (figs. 97F and 98B), a good penicillin producing strain from 

 which high yielding substrains suitable for surface production were de- 

 veloped (Raper and Alexander, 1945), is marked by comparatively loose- 

 textured colonies with centers often more or less flocculent and marginal 

 areas heavy sporing, velvety, plane or nearly so; abundant yellow exudate 

 and yellow pigmentation in colony reverse are produced; penicilli are regu- 

 larly small and often consist of two or three terminal metulae bearing small 

 clusters of sterigmata. The pattern of its penicilli is somewhat suggestive 

 of ramigenous members of the Monoverticillata, but cultural and physio- 

 logical characters unquestionably place it with P. notatum. 



NRRL 1249.B21 (fig. 97D), a high yielding substrain developed from 

 the original Fleming culture (Raper and Alexander, 1945 and Moyer and 

 Coghill, 1946a), is marked by more rapidly growing colonies that are rather 



