Alkylresorcinols are abundant lipid components in different strains of Azotobacter chroococcum and Pseudomonas spp

Abstract

The occurrence of various amounts of 5-n-alkylresorcinols was shown in lipids extracted from 14 bacterial strains of Azotobacter chroococcum as well as from strains of Pseudomonas aureofaciens, P. chlororapsis, and P. fluorescens. The amount of alkylresorcinols found varied from 2.3 to 56.2 g/mg (dry weight) of cells in A. chroococcum and from 0.2 to 0.8 g/mg (dry weight) of cells in Pseudomonas spp. Strains of both genera produce saturated homologs with C 13 to C 27 side chains. C 19 , C 21 , and C 23 homologs are predominant in and characteristic for A. chroococum strains, the C 15 homolog is predominant in and characteristic for P. chlororapsis and P. fluorescens, and the C 17 homolog is predominant in and characteristic for P. aureofaciens. The presence of 5-n-(2-ketoalkyl)resorcinols, not previously observed, was demonstrated in lipids isolated from the cells of A. chroococum Az5.Alkylresorcinols-long-chain, odd-numbered homologs of orcinol (1,3-dihydroxy-5-methylbenzene)-were demonstrated initially only in the plant kingdom. First, their occurrence in plants from the families Anacardiaceae (Anacardium occidentale [cashew]) and Ginkgoaceae (Ginkgo biloba) was demonstrated (24). In these plants mostly unsaturated homologs of 5-n-pentadecylresorcinol were found. Later, homologs with longer side chains and their derivatives were demonstrated in various species of Gramineae, including cereals and several other plant families such as Proteaceae, Myrsinaceae, Myristicaceae, Liliaceae, and Leguminosae (1, 24; also, references therein). Reusch and Sadoff (15,16) Further experiments showed that during encystment of A. vinelandii over 70% of lipids were replaced with resorcinolic and other phenolic lipids (19). Alkylresorcinols consisted of half of these phenolic compounds. In contrast to plant sources, the alkyl chains of hitherto identified bacterial alkylresorcinols are exclusively saturated.The biological role of these compounds in bacterial organisms is not known yet. Their increasing level during encystment and alteration of cellular metabolism suggest that they are autoregulatory anabiotic compounds (3, 13).Although occurrence of resorcinolic lipids in single strains of Azotobacter and Pseudomonas spp. was indicated, there were no data concerning the abundance of these compounds in various strains from these genera. In this paper we present data indicating that the occurrence of 5-n-alkylresorcinol homologs of various chain lengths is also a characteristic feature in various Azotobacter and Pseudomonas strains and species. MATERIALS AND METHODS Microorganisms.Azotobacter strains were isolated from the organic layer of arable land collected near Wrocl ͞aw. They were identified by the method of Thompson and Skerman (20) at the Department of Agricultural Microbiology, Agricultural University at Wrocl ͞aw. There were 14 strains of A. chroococcum: Az1, Az4, Az5, Az7, Az6, Az8, Az9, Az10, Az11, Az12, Az13, Az15, Az17, and Az18. Three strains from the genus Pseudomonas were used for the study. P. aureofaciens PGS12...

5-n-Alkylresorcinols from the Nitrogen-fixing Soil Bacterium Azotobacter chroococcum Az12

“…The AR-containing fraction (4.8 mg) was purified from the cell extract by column chromatography on Sephadex LH-20 followed by preparative TLC, whereas no ARs were detected in the post-culture medium extract. Our finding is in a good agreement with previously published studies of ARs in A. vinelandii (Reusch and Sadoff, 1979;Su et al, 1981), however remains inconsistent with the report by Kozubek et al (1996), who demonstrated the presence of small quantities of ARs also in supernatants. From a physico-chemical point of view, secretion of certain amounts of ARs into the culture liquid medium is possible due to their amphiphilic character and, in fact, has been found in few microorganisms (Zarnowski et al, 2000a;Zarnowski, Hendrich and Pietr, unpublished).…”

“…Our finding is in a good agreement with previously published studies of ARs in A. vinelandii (Reusch and Sadoff, 1979;Su et al, 1981), however remains inconsistent with the report by Kozubek et al (1996), who demonstrated the presence of small quantities of ARs also in supernatants. From a physico-chemical point of view, secretion of certain amounts of ARs into the culture liquid medium is possible due to their amphiphilic character and, in fact, has been found in few microorganisms (Zarnowski et al, 2000a;Zarnowski, Hendrich and Pietr, unpublished). AR molecules exhibit an affinity to biological membranes, because their partition coefficient in an octanol/water system is more than 7.4 (Kozubek and Tyman, 1999).…”

“…Ions that were produced by bombarding the sample with 6 keV Xe atoms were accelerated through a potential of 10 kV, and 3-nitrobenzyl alcohol (3-NBA) was used as a matrix. For GC/ EI-MS, ditrimethylsilyl-derivatives of ARs were used (Zarnowski et al, 2000b). 1 µl of the derivatized sample was injected into a HP 5890 Series II gas chromatograph equipped with a DB-5MS column (φ 0.25 mm ¥ 15 m, 0.25 µm film thickness; Agilent Technologies, Palo Alto, CA, USA) and connected to a HP 5973 mass selective detector.…”

“…ARs have also been shown in Azotobacter vinelandii, but their occurrence was attributed to metabolically altered cysts only (Batrakov et al, 1977;Reusch and Sadoff, 1979;Su et al, 1981). Further experiments (Kozubek et al, 1996) reported the presence of ARs also in vegetative cells of A. chroococcum, however, their real function remains unknown. In this study, we thoroughly describe the isolation and characterization of ARs biosynthesised in vegetative cells of A. chroococcum Az12.…”

Alquilresorcinoles: Compuestos Naturales con Importancia Biológica

“…Estos metabolitos han sido encontrados en varios organismos de plantas, hongos, bacterias y esponjas marinas (Barrow y Capon, 1991; Kozubek et al, 1996; Kozubek y Tyman, 1999; Zarnowski et al, 1999;Zarnowski et al, 2000a). Los lípidos resorcinólicos estructuralmente están definidos por una molécula con características anfipáticas debido a que en su estructura tiene una cadena alquil hidrofóbica derivada de la biosíntesis de los ácidos grasos y un anillo resorcinol hidrofílico proveniente de la vía biosintética de los policétidos; tal estructura le confiere numerosas propiedades, asociadas a la conformación de la bicapa lipídica, respiración mitocondrial, bioquímica celular, y estructura de la membrana, afectando las propiedades físico-químicas de microorganismos patógenos, (Kozubek y Tyman, 1999;Zarnowski et al, 2002;Bitkov et al, 1992).…”