C1 BACTERIA IN THE WATER COLUMN OF CHESAPEAKE BAY, USA .3. IMMUNOLOGICAL RELATIONSHIPS OF THE TYPE SPECIES OF MARINE MONOMETHYLAMINE-OXIDIZING AND METHANE-OXIDIZING BACTERIA TO WILD ESTUARINE AND OCEANIC CULTURES

C1 bacteria oxidizing methane and monomethylamine (MMA) are readily enriched from seawater and associated marine materials, but only Methylomonas pelagica oxidizing methane and Methylophaga marina oxidizing MMA have been adequately characterized. Antisera with good specificity were prepared against these taxonomically and trophically different oceanic methylotrophs as well as against methanol dehydrogenase, a key enzyme presumably present in all aerobic methylotrophs. These antisera were used in an indirect immunofluorescence procedure to compare the relationship of these type oceanic species to wild-type cultures from the estuarine waters of Chesapeake Bay (USA) and the open sea. Of the 32 methanotrophic enrichments attempted from the Sargasso Sea, 23 (72 %) yielded methane-oxidizers. Of the 27 isolates obtained in pure culture, 25 (96 %) were identical to Methlyomonas pelagica. By contrast, none of the 54 estuarine methane-oxidizers from Chesapeake Bay were identical to M pelagica, 13 % were related and 87 % were unrelated. The anti-MDH (methanol dehydrogenase) serum reacted to 23 % of the wild methanotroph cultures. Of the 18 oceanic methylaminotroph enrichments, 44 % were indistinguishable from Methylophaga marina, 6 % were related, and 50 % were unrelated. In contrast, of the 41 Chesapeake Bay MMA-oxidizers, 12 % were indistinguishable from M marina, 17 % were related, while 71 % were unrelated. The anti-MDH antiserum reacted with only 15 % of the wild MMA-oxidizing bacteria. The implications of the taxonomic affinities and trophic requirements of the methylotrophs to their estuarine and oceanic distribution and to their anaerobic methanogenic bacterial consorts are discussed.