Hyphomonas

Abstract

Hy.pho.mo'nas . Gr. neut. n. hyphos filament; Gr. fem. n. monas a unit, monad; N.L. fem. n. Hyphomonas hypha bearing unit. Proteobacteria / Alphaproteobacteria / Rhodobacterales / Hyphomonadaceae / Hyphomonas Rod‐shaped to oval cells measure 0.5–1.0 μm × 1.0–3.0 μm. Species have a biphasic life cycle and generate a single polar prosthecum. Cell division occurs by budding. Buds are produced at tips of polar prostheca, which are 0.2–0.3 μm in diameter and one to five times the length of the cell body. Young daughter cells are oval to pear shaped, lack prostheca, and are smaller than the mother cell. Motile by means of a single polar to lateral flagellum. Pleomorphic, Gram‐negative, not acid‐fast, aerobic, non‐spore‐forming, and chemoorganotrophic. Species catabolize amino acids or tricarboxylic acid cycle intermediates for energy and growth. All strains are catalase‐ and oxidase‐positive, nonproteolytic, and nonsaccharolytic. Gelatin and starch are not hydrolyzed; no indole formed from tryptophan; no DNase, ornithine decarboxylase, lysine decarboxylase, or coagulase activity. With one exception, all species denitrify. Amino acids are required for heterotrophic growth. Optimal temperature for growth, 22–37°C. Most species have Q‐11 as their major ubiquinone with a significant amount of Q‐10 and minor amounts of Q‐9 and Q‐12. Hyphomonas jannaschiana has Q‐10 as its major ubiquinone. The major cellular fatty acid is C 18:1 ω6 c /ω7 c ; major hydroxy fatty acid is C 12:1 3‐OH. Polar lipids are α‐ d ‐glucopyranosyl diacylglycerol, α‐ d ‐glucuronopyranosyl diacylglycerol, phosphatidyl diacylglycerol, and 1,2‐diacyl‐3‐α‐ d ‐glucuronopyranosyl‐ sn ‐glycerol taurinamide. Members of the genus were isolated from marine habitats. They are primary colonizers of submerged marine surfaces, some species producing dense biofilms. The genus Hyphomonas is classified within the family Hyphomonadaceae . DNA G + C content (mol%) : 58.2–62.5 (genome sequences). Type species : Hyphomonas polymorpha (ex Pongratz 1957) Moore et al. 1984 VP .