Deoxyribonucleic acid base composition of some micrococci and sarcinae.

Abstract

The strains designated in this paper asMicrococcus lysodeikticus, M. sodonensis, M. flavus, Sarcina flava, S. pelagia, S. variabilis, S. marginata, S. subflava, S. citrea, S. lutea andStaphylococcus afermentans have similar DNA base compositions. The mole % GC (guanine plus cytosine) contents in DNA of these strains ranged from 71.8 to 73.3 as calculated from the denaturation temperature (Tm). They may be, therefore, closely related. However, at variance with Kocur and Martinec (1962) they do not seem to be identical withMicrococcus luteus (Schroeter 1872) Cohn 1872, because the neotype culture of the latter species has a different content of guanine and cytosine in its DNA (GC=66.3%). Sarcina aurantiaca, Micrococcus dentrificans andM. luteus have a similar DNA base composition. However, they are not identical as they differ from each other in several physiological characters. In the strains designated asStaphylococcus roseus andSarcina erythromyxa the content of GC varies within the range 72–72.8%. These species do not differ from each other physiologically. They form a pink pigment, reduce nitrates, do not hydrolyze casein and gelatin, and do not produce urease. They seem, therefore, to be identical, which confirms the conclusion of Kocur and Martinec (1962) who designated them asMicrococcus roseus Flugge 1886. Micrococcus conglomeratus differs significantly in DNA base composition from almost all strains of the groupM. lysodeikticus—Staphylococcus afermentans, also fromMicrococcus luteus, M. roseus andM. denitrificans. It differs fromSarcina aurantiaca only physiologically.