English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The distribution of 3-ketolactose formation among members of the alpha subclass of the Proteobucteriu was investigated by the Benedict reagent test and by a more sensitive quantitative method in which high-perfor- mance liquid chromatography was used. 3-Ketolactose formation activity was found in strains of Agrobucterium biovar 1 and in strains of eight species of the genus Sphingumonus, including Sphingumunus puucimobilis (the type species), which belong to the alpha-2 and alpha-4 subclasses of the Proteobucteriu, respectively. Weak activity was found in Erythrobucter longus IF0 1412(iT (T = type strain), a member of the alpha-4 subclass of the Pruteubucteriu. The ketosugar was not produced by members of the other taxa of the alpha subclass of the Proteobucteria tested. The ketosugar was isolated from culture broths of S. puucimobilis IF0 13935T and Sphingomonus yunoikuyue IF0 15102T and was identified as 3-ketolactose (4-0-( p-~-xylo-hexopyranosy1-3- u1ose)-D-glucopyranose) by chromatographic analyses and 'H nuclear magnetic resonance spectroscopy. Formation of 3-ketolactose (3KL) (4-O-(P-~-xylo-hexopyr- anosyl-3-ulose)-~-glucopyranose) from lactose is characteristic of strains of Agrobacterium biovar 1 and has been widely used as a taxonomic marker to differentiate distinct biovar groups of the genus Agrobacterium (3-6, 11, 13). This reaction has been reported to be catalyzed by a hexopyranoside:cytochrome c oxidoreductase (EC 1.1.99.13) (25). The structure of 3KL was elucidated by nuclear magnetic resonance (NMR) spectros- copy (100 MHz) and polarography in 1969 (1). Recently, the NMR spectrum of 3KL was completely analyzed at 500 MHz by two-dimensional NMR techniques (7). Holmes and Roberts (9) found that strains of the so-called "Agrobacterium yellow group" are also positive in the 3KL test, although DNA-rRNA hybridization experiments revealed that these bacteria are more closely related to Sphingomonas cap- sulata than to the genus Agrobacterium (2, 8). During studies on strains isolated from roots of plants, we found that certain yellow-pigmented bacteria were positive in the 3KL test and that these organisms could be classified in the genus Sphin- gomonas on the basis of biochemical and chemotaxonomic characteristics. The genus Sphingomonas was proposed by Yabuuchi et al. (28) for yellow-pigmented, nonfermentative, gram-negative rods. These bacteria contain large amounts of a unique sphin- goglycolipid and ubiquinone 10 and have high DNA G+C contents (62 to 68 mol%). Members of the genus Agrobacte- rium are known to belong to the alpha-2 subclass of the Pro- teobacteria (21,26), whereas members of the genus Sphingomo- nas belong to the alpha-4 subclass (24). Thus far, formation of 3KL from lactose has been thought to be a characteristic prop- erty of biovar 1 of the genus Agrobacterium, and this activity has not been found in any other taxon previously. In this paper we describe the production of 3KL by members of the genus Sphingomonas and the distribution of 3KL-pro-

Distribution of 3-Ketolactose Formation among Sphingomonas spp. and Other Members of the Alpha Subclass of the Proteobacteria