Dorothy I. Fennell

A medium for rapid identification and enumeration of Aspergillus flavus and related organisms.

The research reported in this note was prompted by a chance observation during a study of Clostridium perfringens (Veillon & Zuber) Holland in corn and milled corn products on Sulfide Polymyxin Sulfadiazine (SPS) agar (Difco 1 0845). Plates of this complex medium, allowed to sit on the bench during examination of corn samples, became contaminated with a fungus, later identified as A. flavus, that produced a persistent bright yellow-orange pigment, near Cadmium Yellow 2 (P1. III, Ridgway, 1912), under nonsporulating colonies. Both the pigmentation and lack of sporulation were considered desirable attributes: While the former would permit easy detection, the latter would prevent development of secondary colonies with resultant inaccuracies in counts. Experimentation showed that a simplified medium consisting of 1.5% tryptone, 1.0% yeast extract, 0.05% ferric citrate, and 1.5% agar (Aspergillus differential medium, ADM) could be substituted for SPS without changing the reverse pigmentation or inducing sporulation of the isolate. The ferric ion was found to be essential for pigment production.

The microbiological production of gibberellins A and X.

Abstract A method is described for the production of crude crystalline gibberellin in yields of about 12 g. per 160 gal. of culture liquor. This product is a mixture of the known gibberellin A ([α]D +36 °) and a new gibberellin (C19H22O6) with a rotation of [α]D +92 °.

The Genus Circinella

The genus Circinella was erected by van Tieghem and Le Monnier (34) in 1873 to include certain forms closely related to Mucor but differ? ing from that genus in producing sporangiophores bearing circinate branches terminated by globose sporangia with persistent sporangial walls. These workers described three species in their new genus: C. umbellata with sporangia borne in umbels on circinate branches; C. spinosa with a sterile spine produced just below the sporangium on circinate branches from the main sporangiophore; and C. glomerata later recognized by van Tieghem (32) to be a species of Helicostylum. In 1872 (33) van Tieghem and Le Monnier had proposed, but did not characterize, the name Circinumbella to cover Mucor-like organisms with umbels of circinately borne sporangia. Circinumbella appears to have been based upon what is now known as Circinella umbellata. Since no generic description of Circinumbella was given and since there is no reference to any species having been placed in it, it would seem best, therefore, to treat it as a provisional name. Schroeter (28) in 1886 reduced Circinella from the rank of genus to that of a subgenus under Mucor. Subsequent workers have refused to accept this classification and have continued to recognize Circinella as a

Further Investigations on the Preservation of Mold Cultures

Unprecedented study has centered upon the saprophytic molds during the past several years. This has resulted in large measure from the search for new antibiotic substances and from an intensive study of so-called deterioration processes. In addition, there has been a generally quickened interest in these fungi in all fields where they occur as contaminants or where they seem to offer promise of producing desirable metabolic products. As the result of this increased study, workers in many laboratories have established culture collections of varying size and diversity. In maintaining these cultures, two considerations are uppermost, namely, (1) how to prolong viability, and (2) how to preserve morphological and physiological characteristics in unaltered form. Much attention has been given to these matters at the Northern Regional Research Laboratory, and a considerable amount of information has accumulated since our collection of cultures was established in 1940. The purpose of this paper is to review briefly some of our experiences with different methods of culture preservation, and to consider particularly some recent results obtained with cultures preserved in lyophilized form. Four years ago Raper and Alexander (1945) reported the successful application of the so-called lyophil process to the preservation of a wide variety of molds. Prior to this time, bacteriologists such as Shackell (1909), Hammer (1911), Rogers (1914), Swift (1921 and 1937), Elser, Thomas and Steffan (1935), and Flosdorf

A new pathogenic species of Aspergillus.

A new species, Aspergillus bisporus, isolated from soil collected at Clarksburg, Maryland, and Bainbridge, Georgia, is described. On standard media the species is characterized by conidial heads with uniseriate phialides bearing short chains of large, globose, black, coarsely dentate conidia and more specifically by the production of two conidial forms on high-sugar medium. The second type of conidial structure developed on M40Y agar bears long, light-olivish conidial chains consisting of smooth to slightly rough, globose to elliptical conidia. Incubation at 37-45 C enhances the development of the second conidial form. Conidia of A. bisporus survive for several months in brain, lung, liver and spleen of mice without any evidence of multiplication. However, extensive growth causing chronic nephritis occurs in the kidney.