Am. Lysenko et al., GUANINE PLUS CYTOSINE DNA CONTENT OF PSYCHROPHILIC METHANOTROPH AND ITS DNA - DNA HYBRIDIZATION WITH METHANOTROPHS OF TYPE-1, Microbiology, 63(5), 1994, pp. 528-529
Obligate methanotrophs are unique microorganisms utilizing methane or
methanol as a sole carbon and energy source. In 1970 Whittenbury et al
. isolated more than 100 strains of methanotrophs and classified them
in five groups: Methylomonas, Methylobacter, Methylococcus, Methylocys
tis, and Methylosinus [1] with the status of genera [2, 3], but only M
ethylomonas and Methylococcus have been validated. In 1981, Romanovska
ya suggested including the Methylobacter group in the genus Methylococ
cus and this inclusion was validated [4, 5]. However, in 1991 due to i
ts heterogeneity the genus Methylococcus was subdivided into two clust
ers of methylococci with low and high guanine-plus-cytosine (G + C) co
ntent of DNA [6]. The analysis of 5S RNA sequences also confirmed a re
asonable arrangement of methanotrophs into five groups [7].