1
|
Wang T, Dong Z, Zhou D, Sun K, Zhao Y, Wang B, Chen Y. Structure and immunostimulating activity of a galactofuranose-rich polysaccharide from the bamboo parasite medicinal fungus Shiraia bambusicola. JOURNAL OF ETHNOPHARMACOLOGY 2020; 257:112833. [PMID: 32289476 DOI: 10.1016/j.jep.2020.112833] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 03/09/2020] [Accepted: 04/01/2020] [Indexed: 06/11/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Shiraia bambusicola is a parasitic fungus on the twigs of bamboos. Its relatively large stroma has high medicinal value and can treat a variety of diseases such as rheumatoid arthritis, cold stomach pain, sciatica, injuries, chronic bronchitis, and infantile. It is widely distributed in many provinces in Southern China and also is also found in Japan. AIM OF THE STUDY Medicinal fungi were important resources for bioactive polysaccharides. To explore bioactive polysaccharides from Shiraia bambusicola, a heteropolysaccharide SB2-1 was purified and obtained from S. bambusicola and its immunostimulating activity was researched. MATERIALS AND METHODS The polysaccharide from S. bambusicola was extracted and purified using enzyme assisted extraction, ethanol precipitation, anion-exchange and size-exclusion chromatography. Molecular weight of polysaccharide was estimated by high performance gel permeation chromatography. Monosaccharide compositions were determined by high performance liquid chromatography after pre-column derivatization and UV detection. Structure information was elucidated by IR spectrum, GC-MS analysis after methylation and gradual acid hydrolysis of the polysaccharide. The RAW264.7 cells were used to study the immunostimulating activity in vitro. RESULTS Physicochemical and structural analyses showed that SB2-1 was a neutral heteropolysaccharide with molecular weight at 22.2 kDa and consisted of glucose, galactose and mannose at a ratio of 2.0:1.5:1.0. The structure of SB2-1 was a branched polysaccharides composed of a mannan core and side chains consisted of glucose and galactose. The mannan core was composed of (1→2)-Manp as the main chain. Glucose with (1→4)-D-Glcp, (1→2)-D-Glcp and (1→6)-D-Glcp at different degrees of polymerization were linked at C-6 and C-3 of the (1→2)-Manp as the side chains. The galactose with the linages of (1→6)-D-Galf, →2)-D-Galf(1→ and terminal D-Galf(1→ also existed in the side chain. The study on the immunostimulating activities of SB2-1 and its core structure P-2 were investigated on RAW264.7 macrophages. The results showed that SB2-1 could activate RAW264.7 macrophage and significantly improve its phagocytic ability by neutral red uptake experiment. Meanwhile, SB2-1 increased significantly higher inducible nitric oxide synthase (iNOS) production and the productions of IL-1, IL-6, IL-12 and TNF-α. The effect of SB2-1 was better than its core structure P-2 produced by gradual acid hydrolysis, which meant the side chains played an important role in the immunostimulating activities. CONCLUSIONS The investigation demonstrated that the galactofuranose-containing mannogalactoglucan was characteristic polysaccharides in S. bambusicola and could enhance the activation of macrophages.
Collapse
Affiliation(s)
- Teng Wang
- College of Food and Pharmacy, Zhejiang Ocean University, 1 South Haida Road, Zhoushan, 316000, People's Republic of China
| | - Zhe Dong
- College of Food and Pharmacy, Zhejiang Ocean University, 1 South Haida Road, Zhoushan, 316000, People's Republic of China
| | - Dejian Zhou
- College of Food and Pharmacy, Zhejiang Ocean University, 1 South Haida Road, Zhoushan, 316000, People's Republic of China
| | - Kunlai Sun
- College of Food and Pharmacy, Zhejiang Ocean University, 1 South Haida Road, Zhoushan, 316000, People's Republic of China
| | - Yuqin Zhao
- College of Food and Pharmacy, Zhejiang Ocean University, 1 South Haida Road, Zhoushan, 316000, People's Republic of China
| | - Bin Wang
- College of Food and Pharmacy, Zhejiang Ocean University, 1 South Haida Road, Zhoushan, 316000, People's Republic of China
| | - Yin Chen
- College of Food and Pharmacy, Zhejiang Ocean University, 1 South Haida Road, Zhoushan, 316000, People's Republic of China; Zhejiang Provincial Engineering Technology Research Center of Marine Biomedical Products, 1 South Haida Road, Zhoushan, 316000, People's Republic of China.
| |
Collapse
|
2
|
Hager FF, Sützl L, Stefanović C, Blaukopf M, Schäffer C. Pyruvate Substitutions on Glycoconjugates. Int J Mol Sci 2019; 20:E4929. [PMID: 31590345 PMCID: PMC6801904 DOI: 10.3390/ijms20194929] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 09/25/2019] [Accepted: 09/27/2019] [Indexed: 12/15/2022] Open
Abstract
Glycoconjugates are the most diverse biomolecules of life. Mostly located at the cell surface, they translate into cell-specific "barcodes" and offer a vast repertoire of functions, including support of cellular physiology, lifestyle, and pathogenicity. Functions can be fine-tuned by non-carbohydrate modifications on the constituting monosaccharides. Among these modifications is pyruvylation, which is present either in enol or ketal form. The most commonly best-understood example of pyruvylation is enol-pyruvylation of N-acetylglucosamine, which occurs at an early stage in the biosynthesis of the bacterial cell wall component peptidoglycan. Ketal-pyruvylation, in contrast, is present in diverse classes of glycoconjugates, from bacteria to algae to yeast-but not in humans. Mild purification strategies preventing the loss of the acid-labile ketal-pyruvyl group have led to a collection of elucidated pyruvylated glycan structures. However, knowledge of involved pyruvyltransferases creating a ring structure on various monosaccharides is scarce, mainly due to the lack of knowledge of fingerprint motifs of these enzymes and the unavailability of genome sequences of the organisms undergoing pyruvylation. This review compiles the current information on the widespread but under-investigated ketal-pyruvylation of monosaccharides, starting with different classes of pyruvylated glycoconjugates and associated functions, leading to pyruvyltransferases, their specificity and sequence space, and insight into pyruvate analytics.
Collapse
Affiliation(s)
- Fiona F Hager
- Department of NanoBiotechnology, NanoGlycobiology unit, Universität für Bodenkultur Wien, Muthgasse 11, A-1190 Vienna, Austria.
| | - Leander Sützl
- Department of Food Science and Technology, Food Biotechnology Laboratory, Muthgasse 11, Universität für Bodenkultur Wien, A-1190 Vienna, Austria.
| | - Cordula Stefanović
- Department of NanoBiotechnology, NanoGlycobiology unit, Universität für Bodenkultur Wien, Muthgasse 11, A-1190 Vienna, Austria.
| | - Markus Blaukopf
- Department of Chemistry, Division of Organic Chemistry, Universität für Bodenkultur Wien, Muthgasse 18, A-1190 Vienna, Austria.
| | - Christina Schäffer
- Department of NanoBiotechnology, NanoGlycobiology unit, Universität für Bodenkultur Wien, Muthgasse 11, A-1190 Vienna, Austria.
| |
Collapse
|
3
|
Kenyon JJ, Speciale I, Hall RM, De Castro C. Structure of repeating unit of the capsular polysaccharide from Acinetobacter baumannii D78 and assignment of the K4 gene cluster. Carbohydr Res 2016; 434:12-17. [DOI: 10.1016/j.carres.2016.07.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 06/23/2016] [Accepted: 07/12/2016] [Indexed: 01/17/2023]
|
4
|
D'Haeze W, Glushka J, De Rycke R, Holsters M, Carlson RW. Structural characterization of extracellular polysaccharides of Azorhizobium caulinodans and importance for nodule initiation on Sesbania rostrata. Mol Microbiol 2004; 52:485-500. [PMID: 15066035 DOI: 10.1111/j.1365-2958.2004.03989.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
During lateral root base nodulation, the microsymbiont Azorhizobium caulinodans enters its host plant, Sesbania rostrata, via the formation of outer cortical infection pockets, a process that is characterized by a massive production of H(2)O(2). Infection threads guide bacteria from infection pockets towards nodule primordia. Previously, two mutants were constructed that produce lipopolysaccharides (LPSs) similar to one another but different from the wild-type LPS, and that are affected in extracellular polysaccharide (EPS) production. Mutant ORS571-X15 was blocked at the infection pocket stage and unable to produce EPS. The other mutant, ORS571-oac2, was impaired in the release from infection threads and was surrounded by a thin layer of EPS in comparison to the wild-type strain that produced massive amounts of EPS. Structural characterization revealed that EPS purified from cultured and nodule bacteria was a linear homopolysaccharide of alpha-1,3-linked 4,6-O-(1-carboxyethylidene)-D-galactosyl residues. In situ H(2)O(2) localization demonstrated that increased EPS production during early stages of invasion prevented the incorporation of H(2)O(2) inside the bacteria, suggesting a role for EPS in protecting the microsymbiont against H(2)O(2). In addition, ex planta assays confirmed a positive correlation between increased EPS production and enhanced protection against H(2)O(2).
Collapse
Affiliation(s)
- Wim D'Haeze
- Complex Carbohydrate Research Center, The University of Georgia, 315 Riverbend Road, Athens, GA 30602-4712, USA.
| | | | | | | | | |
Collapse
|
5
|
Misevic GN, Guerardel Y, Sumanovski LT, Slomianny MC, Demarty M, Ripoll C, Karamanos Y, Maes E, Popescu O, Strecker G. Molecular recognition between glyconectins as an adhesion self-assembly pathway to multicellularity. J Biol Chem 2003; 279:15579-90. [PMID: 14701844 DOI: 10.1074/jbc.m308927200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The appearance of multicellular forms of life has been tightly coupled to the ability of an organism to retain its own anatomical integrity and to distinguish self from non-self. Large glycoconjugates, which make up the outermost cell surface layer of all Metazoans, are the primary candidates for the primordial adhesion and recognition functions in biological self-assembly systems. Atomic force microscopy experiments demonstrated that the binding strength between a single pair of Porifera cell surface glyconectin 1 glycoconjugates from Microciona prolifera can hold the weight of 1600 cells, proving their adhesion functions. Here, measurement of molecular self-recognition of glyconectins (GNs) purified from three Porifera species was used as an experimental model for primordial xenogeneic self/non-self discrimination. Physicochemical and biochemical characterization of the three glyconectins, their glycans, and peptides using gel electrophoresis, ultracentrifugation, NMR, mass spectrometry, glycosaminoglycan-degrading enzyme treatment, amino acid and carbohydrate analyses, and peptide mapping showed that GNs define a new family of proteoglycan-like molecules exhibiting species-specific structures with complex and repetitive acidic carbohydrate motives different from the classical proteoglycans and mucins. In functional self-assembly color-coded bead, cell, and blotting assays, glyconectins displayed species-specific recognition and adhesion. Affinity-purified monospecific polyclonal antibodies prepared against GN1, -2, and -3 glycans selectively inhibited cell adhesion of the respective sponge species. These results together with species-specific coaggregation of GN carbohydrate-coated beads with cells showed that GN glycans are functional in cell recognition and adhesion. The specificity of carbohydrate-mediated homophilic GN interactions in Porifera approaches the binding selectivity of the evolutionarily advanced immunoglobulin superfamily. Xenoselectivity of primordial glyconectin to glyconectin recognition may be a new paradigm in the self-assembly and non-self discrimination pathway of cellular adhesion leading to multicellularity.
Collapse
Affiliation(s)
- Gradimir N Misevic
- Laboratoire des Processus Intégratifs Cellulaires, UMR 6037 CNRS, Faculté des Sciences et Techniques de Rouen, 76821 Mont St Aignan Cedex, France.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Yang BY, Brand J, Montgomery R. Pyruvated galactose and oligosaccharides from Erwinia chrysanthemi Ech6 extracellular polysaccharide. Carbohydr Res 2001; 331:59-67. [PMID: 11284505 DOI: 10.1016/s0008-6215(01)00004-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The acidic extracellular polysaccharide of Ech6 was depolymerized by fuming HCl. The pyruvated sugars were isolated and characterized by methods that included a combination of low-pressure gel-filtration and high-pH anion-exchange chromatographies, methylation linkage analyses, mass (GC-MS and MALDI-TOF MS) and 1H NMR (1D and 2D) spectroscopies. The following pyruvated sugars were obtained: 4,6-O-(1-carboxyethylidene)-D-Galp; 4,6-O-(1-carboxyethylidene)- alpha-D-Galp-(1-->4)-beta-D-GlcAp-(1-->3)-D-Galp; 4,6-O-(1-carboxyethylidene)-alpha-D-Galp-(1-->4)-alpha-D-GlcAp- (1-->3)-alpha-D-Galp-(1-->3)-L-Fucp; 4,6-O-(1-carboxyethylidene)-alpha-D-Galp-(1-->4)-beta-D-GlcAp-(1-->3) -alpha-D-Galp-(1-->3)-L-[beta-D-Glcp-(1-->4)]-Fucp. These oligosaccharides present potential haptenes for the development of specific antibodies and confirm the partial structure proposed previously for the extracellular polysaccharide from Erwinia chrysanthemi Ech6 [Yang, B. Y.; Gray, J. S. S.; Montgomery, R. Int. J. Biol. Macromol., 1994, 16, 306-312].
Collapse
Affiliation(s)
- B Y Yang
- Department of Biochemistry, College of Medicine, University of Iowa, Iowa City 52242, USA
| | | | | |
Collapse
|
7
|
Rougeaux H, Talaga P, Carlson RW, Guezennec J. Structural studies of an exopolysaccharide produced by Alteromonas macleodii subsp. fijiensis originating from a deep-sea hydrothermal vent. Carbohydr Res 1998; 312:53-9. [PMID: 9836450 DOI: 10.1016/s0008-6215(97)10061-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The structure of the exopolysaccharide produced by Alteromonas macleodii subsp. fijiensis recovered from a deep-sea hydrothermal vent has been investigated. By means of chemical analysis and NMR studies, the repeating unit of the polymer was deduced to be a branched hexasaccharide with the structure shown. [formula: see text]
Collapse
|
8
|
Cérantola S, Marty N, Montrozier H. Structural studies of the acidic exopolysaccharide produced by a mucoid strain of Burkholderia cepacia, isolated from cystic fibrosis. Carbohydr Res 1996; 285:59-67. [PMID: 9011377 DOI: 10.1016/s0008-6215(96)90170-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The acidic exopolysaccharide produced by a mucoid strain of Burkholderia cepacia isolated from a cystic fibrosis patient, was purified by cetyltrimethylammonium bromide precipitation and/or anion-exchange chromatography. Based on the sugar composition and permethylation analyses, supported by GLC-MS and NMR spectroscopy analyses, the repeating-unit of the polysaccharide was established as -->3)-beta-D-Glcp-(1-->3)-[4,6-O-(1-carboxyethylidene)]-alpha-D-Gal p-(1-->.
Collapse
Affiliation(s)
- S Cérantola
- Département des Glycoconjugués et Biomembranes, Laboratoire de Pharmacologie et Toxicologie Fondamentales du CNRS, Toulouse, France
| | | | | |
Collapse
|
9
|
|
10
|
Spillmann D, Hård K, Thomas-Oates J, Vliegenthart J, Misevic G, Burger M, Finne J. Characterization of a novel pyruvylated carbohydrate unit implicated in the cell aggregation of the marine sponge Microciona prolifera. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)38662-4] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
|
11
|
O'Neill MA, Robison PD, Chou KJ, Darvill AG, Albersheim P. Evidence that the acidic polysaccharide secreted by Agrobacterium radiobacter (ATCC 53271) has a seventeen glycosyl-residue repeating unit. Carbohydr Res 1992; 226:131-54. [PMID: 1499017 DOI: 10.1016/0008-6215(92)84060-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The extracellular anionic polysaccharide produced by the bacterium Agrobacterium radiobacter (ATCC 53271) contains D-galactose, D-glucose, and pyruvic acid in the molar ratio 2:15:2. Analysis of the methylated polysaccharide indicated the presence of terminal, non-reducing glucosyl, 3-, 4-, 6-, 2,4-, and 4,6-linked glucosyl residues, 3-linked 4,6-O-[(S)-1-carboxyethylidene]glucosyl residues, and 3-linked galactosyl residues. Partial acid hydrolysis of the methylated polysaccharide, followed by reduction with NaB2H4 and then O-ethylation, gave a mixture of alkylated oligoglycosyl alditols that were separated by reversed-phase h.p.l.c. and analyzed by 1H-n.m.r. spectroscopy, g.l.c.-m.s., and glycosyl-linkage composition analysis. Smith degradation of the polysaccharide gave three diglycosyl alditols that were separated by semi-preparative, high-pH anion-exchange chromatography, and were analyzed by 1H-n.m.r. spectroscopy, g.l.c.-m.s., and glycosyl-linkage composition analysis. The polymer obtained by NaBH4 reduction of the periodate-oxidized polysaccharide was methylated, and the noncyclic acetals were hydrolyzed with aq. 90% formic acid to generate a mixture of partially O-methylated mono- and di-glycosyl alditols. The partially O-methylated oligoglycosyl alditols were O-ethylated. The resulting alkylated oligoglycosyl alditols were separated by reverse-phase h.p.l.c. and then characterized by 1H-n.m.r. spectroscopy, g.l.c.-m.s., and glycosyl-linkage composition analysis. The results from the studies described here provide strong evidence that the acidic polysaccharide secreted by A. radiobacter (ATCC 53271) has a heptadecasaccharide repeating unit.
Collapse
Affiliation(s)
- M A O'Neill
- Complex Carbohydrate Research Center, University of Georgia, Athens 30602
| | | | | | | | | |
Collapse
|
12
|
Fontaine T, Talmont F, Dutton GG, Fournet B. Analysis of pyruvic acid acetal containing polysaccharides by methanolysis and reductive cleavage methods. Anal Biochem 1991; 199:154-61. [PMID: 1812780 DOI: 10.1016/0003-2697(91)90083-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The mass spectra of permethylated methyl 4,6-O-(1-carbomethoxyethylidene)-D-hexopyranoside and 1,5-anhydro-D-hexitol of glucose, galactose, and mannose and permethylated methyl 5,6-O-(1-carbomethoxyethylidene)-D-galactofuranoside and 1,4-anhydro-D-galactitol have been determined. The stability of each compound toward methanolysis and reductive cleavage is discussed. These techniques permit the identification of the acetalic linkages of pyruvic acid present in polysaccharides.
Collapse
Affiliation(s)
- T Fontaine
- Laboratoire de Chimie Biologique, Université des Sciences et Techniques de Lille Flandres-Artois, Villeneuve d'Ascq, France
| | | | | | | |
Collapse
|
13
|
Levery SB, Zhan H, Lee CC, Leigh JA, Hakomori S. Structural analysis of a second acidic exopolysaccharide of Rhizobium meliloti that can function in alfalfa root nodule invasion. Carbohydr Res 1991; 210:339-47. [PMID: 1878885 DOI: 10.1016/0008-6215(91)80135-a] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- S B Levery
- The Biomembrane Institute, Seattle, WA 98119
| | | | | | | | | |
Collapse
|
14
|
Fontaine T, Wieruszeski JM, Talmont F, Saniez MH, Duflot P, Leleu JB, Fournet B. Exopolysaccharide structure from Bacillus circulans. EUROPEAN JOURNAL OF BIOCHEMISTRY 1991; 196:107-13. [PMID: 2001692 DOI: 10.1111/j.1432-1033.1991.tb15792.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- T Fontaine
- Laboratoire de Chimie Biologique et Unité Mixte de Recherche du CNRS n.111, Université des Sciences et Techniques de Lille Flandres-Artois, France
| | | | | | | | | | | | | |
Collapse
|
15
|
Ha YW, Thomas RL. Identification of 4,6-O-(1-carboxyyethylidine)-d-galactose in extracellular polysaccharide from Palmella texensisUTEX 1708. FEMS Microbiol Lett 1991. [DOI: 10.1111/j.1574-6968.1991.tb04415.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
16
|
Zhan HJ, Gray JX, Levery SB, Rolfe BG, Leigh JA. Functional and evolutionary relatedness of genes for exopolysaccharide synthesis in Rhizobium meliloti and Rhizobium sp. strain NGR234. J Bacteriol 1990; 172:5245-53. [PMID: 2203745 PMCID: PMC213186 DOI: 10.1128/jb.172.9.5245-5253.1990] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Rhizobium meliloti SU47 and Rhizobium sp. strain NGR234 produce distinct exopolysaccharides that have some similarities in structure. R. meliloti has a narrow host range, whereas Rhizobium strain NGR234 has a very broad host range. In cross-species complementation and hybridization experiments, we found that several of the genes required for the production of the two polysaccharides were functionally interchangeable and similar in evolutionary origin. NGR234 exoC and exoY corresponded to R. meliloti exoB and exoF, respectively. NGR234 exoD was found to be an operon that included genes equivalent to exoM, exoA, and exoL in R. meliloti. Complementation of R. meliloti exoP, -N, and -G by NGR234 R'3222 indicated that additional equivalent genes remain to be found on the R-prime. We were not able to complement NGR234 exoB with R. meliloti DNA. In addition to functional and evolutionary equivalence of individual genes, the general organization of the exo regions was similar between the two species. It is likely that the same ancestral genes were used in the evolution of both exopolysaccharide biosynthetic pathways and probably of pathways in other species as well.
Collapse
Affiliation(s)
- H J Zhan
- Department of Microbiology SC-42, University of Washington, Seattle 98195
| | | | | | | | | |
Collapse
|
17
|
Zhan HJ, Levery SB, Lee CC, Leigh JA. A second exopolysaccharide of Rhizobium meliloti strain SU47 that can function in root nodule invasion. Proc Natl Acad Sci U S A 1989; 86:3055-9. [PMID: 2717610 PMCID: PMC287063 DOI: 10.1073/pnas.86.9.3055] [Citation(s) in RCA: 96] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Rhizobium meliloti strain SU47 produces the calcofluor-binding exopolysaccharide, succinoglycan, that is required for alfalfa root nodule invasion. Strains derived from R. meliloti SU47 secreted an acidic exopolysaccharide, EPSb, that replaced succinoglycan in nodule invasion. EPSb, which has not formerly been identified among the Rhizobiaceae, consisted of the repeating unit 4,6-O-(1-carboxyethylidene)-alpha-D-Galp1----3(X-O-Ac)-beta-D-G lcp1----3. EPSb synthesis occurred either in strains containing a mutation in a locus designated mucR or in strains with a recombinant cosmid pMuc. mucR mapped slightly counterclockwise from pyr49 on the chromosome, while pMuc contained genes mapping to the megaplasmid pRmeSU47b. In exoA, -F, and -H mutants, which are deficient in normal succinoglycan secretion and nodule invasion, a transposon Tn5 insertion in mucR or the presence of pMuc resulted in EPSb secretion and a restoration of nodule invasion on Medicago sativa and Melilotus alba. Mutants in exoB and exoC were incapable of succinoglycan and EPSb secretion as well as nodule invasion. A mutant that secreted succinoglycan but was incapable of EPSb secretion invaded nodules normally.
Collapse
Affiliation(s)
- H J Zhan
- Department of Microbiology, University of Washington, Seattle 98195
| | | | | | | |
Collapse
|
18
|
|