Until now there has not been a satisfactory solid medium for determining the growth responses, to Na+, of marine and other bacteria that have specific growth requirements for Na+. A solid medium would be useful to investigators who would like to take advantage of the efficiency of multipoint inoculation when testing for a Na+ requirement. By using 1% gellan gum (Gel-GroTM) as the solidifying agent a medium was formulated that had a contaminating level of Na+ of slightly less than 2 mM in the basal medium. Two species of Aeromonas, which do not require Na+ for growth, and 31 species of Vibrio, which require Na+, were tested for their growth responses to Na+ on this medium. The Aeromonas strains grew well, within 24 h, at all of the Na+ concentrations tested. Approximately 75% of the Vibrio strains did not grow on the basal medium even after a prolonged incubation period. The remaining species were able to grow on the basal medium, but not without a lag period. These lag periods were as short as 36 h for two of the species and in some instances as long as 312 h. These lag periods were of sufficient duration to determine that Na+ stimulated the growth of the Vibrio strains that were able to grow on the basal medium. Approximately 75% of the strains, representing most species of Vibrio, were able to grow if as little as 25 mM Na+ was present in the medium.Key words: low-sodium medium, Na+ requirement, gellan gum, agar substitute, marine bacteria.

Bacteria belonging to the family Vibrionaceae were suspended using saline and a solution prepared from a marine-cations supplement. The effect of this on the profile of oxidized substrates obtained when using Biolog GN MicroPlates was investigated. Thirty-nine species belonging to the genera Aeromonas, Listonella, Photobacterium, and Vibrio were studied. Of the strains studied, species of Listonella, Photobacterium, and Vibrio could be expected to benefit from a marine-cations supplement that contained Na+, K+, and Mg2+. Bacteria that are not of marine origin are usually suspended in normal saline. Of the 39 species examined, 9 were not included in the Biolog data base and were not identified. Of the 30 remaining species, 50% were identified correctly using either of the suspending solutions. A further 20% were correctly identified only when suspended in saline. Three species, or 10%, were correctly identified only after suspension in the marine-cations supplemented solution. The remaining 20% of species were not correctly identified by either method. Generally, more substrates were oxidized when the bacteria had been suspended in the more complex salts solution. Usually, when identifications were incorrect, the use of the marine-cations supplemented suspending solution had resulted in many more substrates being oxidized. Based on these results, it would be preferable to use saline to suspend the cells when using Biolog for identification of species of Vibrionaceae. A salts solution containing a marine-cations supplement would be preferable for environmental studies where the objective is to determine profiles of substrates that the bacteria have the potential to oxidize. If identifications are done using marine-cations supplemented suspending solution, it would be advisable to include reference cultures to determine the effect of the supplement. Of the Vibrio and Listonella species associated with human clinical specimens, 8 out of the 11 studied were identified correctly when either of the suspending solutions was used.

Pantoea agglomerans was isolated from necrotic spots in the leaves of a beach pea (Lathyrus maritimus L.) that grew on the shorelines of Newfoundland, Canada. The bacterium produced cellulase and amylase and was shown to be a wound parasite. Ultrastructural studies of infected leaves showed bacterial aggregates surrounded by pellicles, within intercellular spaces of the necrotic tissue. The bacterium was adapted to temperate climatic conditions. On a culture medium it grew at 5–37 °C, with optimal growth observed at 10–25 °C. Under natural environmental conditions beach peas may be exposed to seawater. When the bacterium was tested for growth tolerance to NaCl, the NaCl was inhibitory, most noticeably at concentrations above 250 mM. Beyond contributing to mechanical injury of plant tissue and keeping the plant surface moist, it is likely that seawater would hinder, rather than enhance, the survival of the bacterium during the phase of the infection process when it was outside the host plant.Key words: beach pea, host–pathogen, Lathyrus maritimus, Pantoea agglomerans.

Bacteria belonging to the family Vibrionaceae were suspended using saline and a solution prepared from a marine-cations supplement. The effect of this on the profile of oxidized substrates obtained when using Biolog GN MicroPlates was investigated. Thirty-nine species belonging to the genera Aeromonas, Listonella, Photobacterium, and Vibrio were studied. Of the strains studied, species of Listonella, Photobacterium, and Vibrio could be expected to benefit from a marine-cations supplement that contained Na+, K+, and Mg2+. Bacteria that are not of marine origin are usually suspended in normal saline. Of the 39 species examined, 9 were not included in the Biolog data base and were not identified. Of the 30 remaining species, 50% were identified correctly using either of the suspending solutions. A further 20% were correctly identified only when suspended in saline. Three species, or 10%, were correctly identified only after suspension in the marine-cations supplemented solution. The remaining 20% of species were not correctly identified by either method. Generally, more substrates were oxidized when the bacteria had been suspended in the more complex salts solution. Usually, when identifications were incorrect, the use of the marine-cations supplemented suspending solution had resulted in many more substrates being oxidized. Based on these results, it would be preferable to use saline to suspend the cells when using Biolog for identification of species of Vibrionaceae. A salts solution containing a marine-cations supplement would be preferable for environmental studies where the objective is to determine profiles of substrates that the bacteria have the potential to oxidize. If identifications are done using marine-cations supplemented suspending solution, it would be advisable to include reference cultures to determine the effect of the supplement. Of the Vibrio and Listonella species associated with human clinical specimens, 8 out of the 11 studied were identified correctly when either of the suspending solutions was used.