Hydrolysis of ? by members of the Haloanaerobiaceae: additional evidence that Haloanaerobium praevalens is related to endospore-forming bacteria

Abstract

Three out of the four described halophilic obligately anaerobic bacteria of the family Haloanaerobiaceae hydrolyze d‐BAPA (N′‐benzoyl‐d‐arginine‐p‐nitroanilide), while showing no or little l‐BAPA hydrolyzing activity. This property was shown earlier to be characteristic only of non‐halophilic Gram‐positive endospore‐forming bacteria of the genera Bacillus and Clostridium. These results suggest that Haloanaerobium praevalens, which has never been shown to produce endospores, but was shown to be related to the endosphere‐forming representatives of the Haloanaerobiaceae on the basis of 16S rRNA nucleotide sequence data, shares other properties characteristics of the endospore‐forming bacteria. Neither significant d‐BAPA nor l‐BAPA hydrolyzing activity was found in Sporohalobacter lortetii.

Complete genome sequence of the extremely halophilic Halanaerobium praevalens type strain (GSLT)

“…H. praevalens cells stain Gram-negative [ 2 ] and electron microscopy in thin section revealed architectural features typical of Gram-negative bacteria [ 2 ]. However, the positive D -BAPA-ase reaction [ 11 ] confirms its phylogenetic affiliation to the endospore-forming firmicutes ( Table 1 ). In this respect, H. praevalens is able to hydrolyze only the D- but not the L- isomer of N’-benzoyl-arginine- p- nitroanilide (BAPA) [ 11 ].…”

“…However, the positive D -BAPA-ase reaction [ 11 ] confirms its phylogenetic affiliation to the endospore-forming firmicutes ( Table 1 ). In this respect, H. praevalens is able to hydrolyze only the D- but not the L- isomer of N’-benzoyl-arginine- p- nitroanilide (BAPA) [ 11 ]. The activity of D -BAPA-ase was highest at low NaCl concentration (100 mM) and completely inhibited at NaCl concentration equal or higher than 1.0 M (~12%) [ 11 ].…”

“…In this respect, H. praevalens is able to hydrolyze only the D- but not the L- isomer of N’-benzoyl-arginine- p- nitroanilide (BAPA) [ 11 ]. The activity of D -BAPA-ase was highest at low NaCl concentration (100 mM) and completely inhibited at NaCl concentration equal or higher than 1.0 M (~12%) [ 11 ]. Strain GSL T is described to be non-motile, although many flagellar genes have been identified in the genome (see below).…”

“…Other members of the genus have been isolated also from high salt environments distributed worldwide [ 7 - 10 ]. The enzymatic activities of the fatty acid synthetase complex and the D -BAPA (N’-benzoyl-arginine- p- nitroanilide)-ase of H. praevalens have been studied in more detail [ 11 , 12 ]. Here we present a summary classification and a set of features for H. praevalens strain GSL T , together with the description of the complete genome sequencing and annotation.…”