In a study of the classification of members of the family Pasteurellaceae, the polyamine patterns of 101 strains were analyzed. These strains included the type strains of species belonging to the genera Actinobacillus, Haemophilus, and Pasteurella and additional strains of selected species, as well as numerous unnamed strains. Members of the genus Actinobacillus sensu stricto were characterized by the presence of 1,3-diaminopropane as the predominant compound. In the majority of the species of the genus Haemophilus sensu stricto 1,3-diaminopropane was also the major compound in the polyamine pattern. In contrast, Haemophilus intermedius subsp. gazogenes and Haemophilus parainfluenzae were characterized by high levels of 1,3-diaminopropane, cadaverine, and putrescine. These results confirmed the findings of Dewhirst et al. (F. E. Dewhirst, B. J. Paster, I. Olsen, and G. J. Fraser, Zentralbl. Bakteriol. Parasitenkd. Infektionskr. Hyg. Abt. 1 Orig. 279:35–44, 1993), who demonstrated that H. parainfluenzae is phylogenetically only distantly related to the type species of the genus Haemophilus, Haemophilus influenzae. The phylogenetic diversity of the genus Pasteurella sensu stricto determined by Dewhirst et al. was also reflected to some extent by different polyamine patterns. The common characteristics found in Pasteurella multocida, Pasteurella canis, Pasteurella dagmatis, Pasteurella stomatis, and Pasteurella sp. strain B were high levels of putrescine and spermidine and the presence of the unusual triamine sym-norspermidine. Pasteurella avium, Pasteurella gallinarum, and Pasteurella volantium contained high concentrations of 1,3-diaminopropane and spermidine. Pasteurella langaa contained only high concentrations of 1,3-diaminopropane, and Pasteurella anatis was characterized by the presence of 1,3-diaminopropane as the predominant compound and high levels of putrescine and spermidine. Our data demonstrate that polyamine patterns are useful for discrimination within the family Pasteurellaceae.

Discrimination of Members of the Family Pasteurellaceae Based on Polyamine Patterns

Strain 130ZTwas isolated from the bovine rumen. It is a facultatively anaerobic, pleomorphic, Gram-negative rod. It exhibits a ‘Morse code’ form of morphology, which is characteristic of the genus Actinobacillus. Strain 130ZTis a capnophilic, osmotolerant succinogen that utilizes a broad range of sugars. It accumulates high concentrations of succinic acid (> 70gl-1). Strain 130ZTis positive for catalase, oxidase, alkaline phosphatase and β-galactosidase, but does not produce indole or urease. Acid but no gas is produced from d-glucose and d-fructose. 16S rRNA sequence analysis places strain 130ZTwithin the family Pasteurellaceae; the most closely related members of the family Pasteurellaceae have 16S rRNA similarities of 95.5% or less with strain 130ZT. Strain 130ZTwas compared with Actinobacillus lignieresii and the related Bisgaard Taxa 6 and 10. Based upon morphological and biochemical properties, strain 130ZTis most similar to members of the genus Actinobacillus within the family Pasteurellaceae. It is proposed that strain 130ZTbe classified as a new species, Actinobacillus succinogenes. The type strain of Actinobacillus succinogenes sp. nov. is ATCC 55618T.

Actinobacillus succinogenes sp. nov., a novel succinic-acid-producing strain from the bovine rumen.

A novel succinic acid-producing bacterium was isolated from bovine rumen. The bacterium is a non-motile, non-spore-forming, mesophilic and capnophilic gram-negative rod or coccobacillus. Phylogenetic analysis based on the 16S rRNA sequence and physiological analysis indicated that the strain belongs to the recently reclassified genus Mannheimia as a novel species, and has been named Mannheimia succiniciproducens MBEL55E. Under 100% CO2 conditions, it grows well in the pH range of 6.0–7.5 and produces succinic acid, acetic acid and formic acid at a constant ratio of 2:1:1. When M. succiniciproducens MBEL55E was cultured anaerobically in medium containing 20 g l–1 glucose as carbon source, 13.5 g l–1 of succinic acid was produced.

Isolation and characterization of a new succinic acid-producing bacterium, Mannheimia succiniciproducens MBEL55E, from bovine rumen

High concentrations of tannins in fodder plants inhibit gastrointestinal bacteria and reduce ruminant performance. Increasing the proportion of tannin-resistant bacteria in the rumen protects ruminants from antinutritional effects. The reason for the protective effect is unclear, but could be elucidated if the mechanism(s) by which tannins inhibit bacteria and the mechanisms of tannin resistance were understood. A review of the literature indicates that the ability of tannins to complex with polymers and minerals is the basis of the inhibitory effect on gastrointestinal bacteria. Mechanisms by which bacteria can overcome inhibition include tannin modification/degradation, dissociation of tannin–substrate complexes, tannin inactivation by high-affinity binders, and membrane modification/repair and metal ion sequestration. Understanding the mechanism of action of tannins and the mechanism(s) bacteria use to overcome the inhibitory effects will allow better management of the rumen ecosystem to reduce the antinutritional effects of tannin-rich fodder plants and thereby improve ruminant production.

Bacterial mechanisms to overcome inhibitory effects of dietary tannins.

The rumen represents the first section of a ruminant animal's stomach, where feed is collected and mixed with microorganisms for initial digestion. The major gas produced in the rumen is CO2 (65.5 mol%), yet the metabolic characteristics of capnophilic (CO2-loving) microorganisms are not well understood. Here we report the 2,314,078 base pair genome sequence of Mannheimia succiniciproducens MBEL55E, a recently isolated capnophilic Gram-negative bacterium from bovine rumen, and analyze its genome contents and metabolic characteristics. The metabolism of M. succiniciproducens was found to be well adapted to the oxygen-free rumen by using fumarate as a major electron acceptor. Genome-scale metabolic flux analysis indicated that CO2 is important for the carboxylation of phosphoenolpyruvate to oxaloacetate, which is converted to succinic acid by the reductive tricarboxylic acid cycle and menaquinone systems. This characteristic metabolism allows highly efficient production of succinic acid, an important four-carbon industrial chemical.

/pdf/the-genome-sequence-of-the-capnophilic-rumen-bacterium-4wed9mjd2u.pdf

T. Fujisawa

Papers

Lonepinella koalarum gen. nov., sp. nov., a New Tannin-Protein Complex Degrading Bacterium