Phylogenetic analysis of the genera Leuconostoc and Aeromonas

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Probe molecule kinetic studies of adsorption on MCM-41

Gases and vapors of varying dimensions were used as probes to investigate the adsorption processes on MCM-41 and precipitated silica, prepared by the same method as for MCM-41, but without the template. The adsorption kinetics of nitrogen, carbon dioxide, n-nonane, and α-pinene were studied for different amounts of preadsorbed gas/vapor as a function of relative pressure. The adsorption kinetics follow a linear driving force model for changes in surface coverage up to the adsorption isotherm plateaus. The variation of rate constant with relative pressure for MCM-41 and precipitated silica showed marked differences associated with adsorption in mesoporous structure, which are attributed to alignment of molecules in the mesopores leading to a pore blocking effect. The results are discussed in terms of differences in the adsorption mechanisms of gas/vapor diffusion in porous materials

Aeromonas australiensis sp. nov., isolated from irrigation water

A Gram-negative, facultatively anaerobic bacillus, designated strain 266T, was isolated from an irrigation water system in the south-west of Western Australia. Analysis of the 16S rRNA gene sequence confirmed that strain 266T belonged to the genus Aeromonas, with the nearest species being Aeromonas fluvialis (99.6% similarity to the type strain, with 6 nucleotide differences) followed by Aeromonas veronii and Aeromonas allosaccharophila (both 99.5 %). Analysis of gyrB and rpoD sequences suggested that strain 266T formed a phylogenetic line independent of other species in the genus. This was confirmed using the concatenated sequences of six housekeeping genes (gyrB, rpoD, recA, dnaJ, gyrA and dnaX) that also indicated that A. veronii and A. allosaccharophila were the nearest relatives. DNA-DNA reassociation experiments and phenotypic analysis further supported the conclusion that strain 266T represents a novel species, for which the name Aeromonas australiensis sp. nov. is proposed, with type strain 266T (=CECT 8023T =LMG 2670T)