362 A MANUAL OF THE PENICILLIA 



isolate from tobacco; NRRL 1951, isolated at this Laboratory in July, 1943, 

 from a cantaloupe; and many others. NRRL 843, from the Biourge Col- 

 lection, through Dr. Paul Simonart in 1936, differs from the above in pro- 

 ducing larger and strongly elliptical conidia ranging up to 4.5 or 5.0^ in 

 long axis. 



All of the cultures listed above produce fair to good yields of penicillin 

 in both surface and submerged cultures. NRRL 1951 is of special interest 

 since it represents the stock from which such high penicillin-yielding natural 

 variants as NRRL 1951. B25, and the artificially induced mutations X-1612 

 and Wis. Q-176 were obtained (see pp. 96-98). NRRL 811 is also of 

 special interest since it represents the first culture which May, Herrick, 

 et al. successfully adapted to the production of gluconic acid by submerged 

 culture techniques (May, et al., 1934 and Moyer, et al., 1936). 



The species is unusually common in nature and shows the same general 

 distribution as listed for the series (see p. 373). 



The species Penicillium. chrysogenum Thom, in a broad sense, includes a 

 number of fairly well-defined cultural aspects. These differ from one 

 another enough to be recognized, but fail to develop sufficient differences 

 to warrant specific or varietal separation. The following strains are repre- 

 sentative of some of these cultural types: 



NRRL 807, the type strain, originally produced fairly loose-textured, 

 radially furrowed colonies that were heavily sporing and strictly velvety 

 throughout, and developed comparatively large, often rebranched penicilli 

 bearing elliptical conidia about 4.0^ in long axis. After forty years of con- 

 tinuous laboratory cultivation the details of fruiting structures remain 

 essentially unchanged, but colonies now tend to be more restricted, some- 

 what fiocculent in central areas, and usually develop a comparatively thin, 

 heavily sporulating but closely velvety marginal zone. Pigmentation of 

 conidial areas and of colony reverse remain unaltered. 



NRRL 1951, cited above as a typical strain, produces comparatively 

 deep, loose-textured, radially but not deeply furrowed, velvety colonies 

 that are heavily sporing throughout, and develop very large, usually re- 

 branched penicilli with strongly elliptical conidia. Exudate formation 

 is often somewhat reduced and pigmentation in colony reverse is less marked 

 than in the type preceding. Natural variants separated from this basic 

 stock by experimental techniques cover almost the entire gamut of cultural 

 types seen in the Penicillium chrysogenum series (Raper and Alexander, 

 1945b). 



NRRL 1984, a good penicillin producing strain (see p. 100), produces 

 colonies strikingly like NRRL 807 above except for a reduction of sterile 

 mycelia in central colony areas ; penicilli are of the same general dimensions 

 and pattern, but conidia are mostly globose to subglobose as in Penicillium 



