FACTORS IMPORTANT FOR THE GROWTH OF HISTOPLASMA CAPSULATUM IN THE YEAST CELL PHASE ON PEPTONE MEDIA I

Abstract

Factors ofimportance inthecultivation ofHistoplasma capsulatum Darling initsyeast cell phase havebeenthesubject ofinvestigation fromthetimeit wasfirst shown, byDemonbreun (1934), that this fungus isthecausative agent of thesystemic mycotic infection, histoplasmosis. Inaclassical presentation of themorphology, life cycle, andpathogenicity ofH.capsulatum, Demonbreun showed thatinvitro cultures ofthis organism always growinmycelial format roomtemperature, butcanbemadetogrowinayeast cell phase(the invivo, tissue form) at37Cunder suitable conditions. Hereported thatalthough the mycelial formflourishes onmanyofthecommonly usednutrient media, good growth oftheyeastlike formofthefungus ...[is] ...obtained onlyonblood agarorother mediarich inproteins. Additional emphasis onthedesirability ofusing blood-containing mediaforyeastcell growth istobefoundinthe publications ofConant(1941) andCampbell (1947). Heavygrowth ofwellencapsulated yeast cells inbothliquid andsolid tryptose mediumfortified with 5percentplasma wasreported byMcVickar (1947). Inthefirst ofaseries of interesting articles, Salvin (1947) described excellent yeast cell development in asemisolid medium, devoid ofblood, blood derivatives, orother proteins. In his1949publication, Salvin gavetheformula ofamedium, completely synthetic saveforthepresence ofagar; thepresence ofbiotin, andeither asulfide or sulfhydryl groupinthis medium, wasregarded bySalvin asessential forthe multiplication ofH.capsulatum initsyeastcell phase. A recent brief note (Salvin, 1950) discusses growth inliquid mediacontaining noprotein. In1946aninvestigation wasbeguninthese laboratories onthefactors important inbringing aboutgrowth ofthis fungus intheyeast cell phase. Attention wasfirst directed toattempting todefine thenature oftherole oftheenhancing action ofblood andblood derivatives. Theelucidation ofthis aspect oftheproblem,briefly presented earlier (McVickar, 1948), isdescribed indetail inthis paper. EXPERIMENTALMETHODS AND RESULTS