A mycoplasma designated strain 4229T (T = type strain) was isolated in 1984 from the turbinate of a duck in France, and similar strains were isolated from geese in France and from a partridge in England. All of these strains were originally identified as Mycophma gallisepticum by immunofluorescence and growth inhibition tests, but subsequent serological and molecular studies indicated only a partial relationship to this species and DNA-DNA hybridization studies revealed only approximately 40 to 46% genetic homology with M. gaUisepticum PG31T. In this study morphological, cultural, and physical investigations were carried out on strain 4229T and partridge strain B2/85, after we first demonstrated the similarity between these organisms by performing a restriction enzyme analysis of their DNAs. Both strains had phenotypic properties very similar to M. gaUisepticum properties, including the presence of an attachment organelle. As a result of these investigations, the organisms were assigned to the class MoUicutes, the order MycophWaZes, and the genus Mycophma. They fermented glucose, reduced triphenyl tetrazolium chloride aerobically and anaerobically, and exhibited hemadsorption and hemagglutination, but other biochemical tests were negative. Apart from a serological cross-reaction with M. gdisepticum, these organisms exhibited no significant relationship with any previously described Mycophma species as determined by growth inhibition or immunofluorescence tests or with a number of additional serovars and unclassified avian strains. This Mycophma taxon therefore appears to be a new species, for which we propose the name Mycophma imitans. The type strain is strain 4229 (= NCTC 11733 = ATCC 51306). The significance of the organism has not been fully investigated, but preliminary in vitro and in vivo studies have indicated that it may be pathogenic.Mycoplasma gallisepticum is a well-known respiratory pathogen of chickens and turkeys, and there have been occasional reports of isolation of this organism from other avian species, such as ducks (4,27), geese (5), pheasants (32, 34), quails (3, 31, 34,38), partridges (34, 42, 44), guinea fowl (40), pigeons (3), and peafowl (29).In 1984 mycoplasmas were isolated from the turbinates of two mule (broiler) ducks in southwest France (15), and these mycoplasmas were identified as M. gallisepticum by immunofluorescence and growth inhibition (GI) tests. Later, the isolation of similar strains from geese in France was reported (11). Additional serological comparisons between these duck and goose isolates and some reference strains of M. gallisepticurn in which GI and metabolism inhibition tests were used showed that the duck and goose strains were closely related to one another but were apparently less closely related to M. gallisepticum (16-18). Sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE) profiles of the proteins, the results of a restriction enzyme analysis of the DNAs, and estimates of the G+C contents also suggested that the goose and duck strains were ...

Dedicated to O t t o W a r b u r g on the occasion of his 80th birthdayThe role of chloride in photosynthetic oxygen evolution was reinvestigated by determining the effect of this ion on photochemical reactions of chloroplasts in which oxygen either is or is not produced. The chloroplasts used were isolated from normal spinach leaves. The level of chloride in the reaction mixture was controlled by washing the isolated chloroplasts and by avoiding a chloride contamination from the water and chemicals used. Chloride was found to be essential for each of the photochemical reactions of chloroplasts in which oxygen is produced. These included (a) photo reduction of TPN, (b) photophosphorylation of the noncyclic type in which TPN or ferricyanide reduction is coupled with ATP formation and (c) photophosphorylation of the aerobic, "pseudocyclic" type in which oxygen production occurs but is masked by an equal oxygen consumption. No chloride requirement was found for the anaerobic, cyclic photophosphorylation in which oxygen is not produced. These results support the view that chloride is an essential cofactor for oxygen evolution in photosynthesis.W a r b u r g 1 discovered that chloride was essential for oxygen evolution by isolated chloroplasts in the presence of the nonphysiological hydrogen (elec tron) acceptors, benzoquinone and ferricyanide. This discovery was confirmed by A r n o n and W h a t l e y 2 and G o r h a m and C l e n d e n n in g 3 but they had little inclination to accept W a r b u r g 's conclusion 1 that chloride served as a coenzyme for oxygen evolu tion in photosynthesis because there was no evidence at the time that chloride was essential for the growth of intact plants; hence, it seemed unlikely that chloride would be required for oxygen evolution in vivo. Moreover, chloride, a common constituent of leaves, could be completely replaced in the in vitro system by bromide 1~3, an anion of doubtful physio logical importance to land plants. A r n o n and W h a t l e y 2 suggested, therefore, that the role of chloride was to protect the photochemical activity of chloro plasts in vitro against inactivation by light. G o r h a m and C l e n d e n n in g 3 drew attention to the effects of

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