Nutritional value of Sesamum indicum L. was improved by Azospirillum and Azotobacter under low input of NP fertilizers.

BACKGROUND: Sesame (Sesame indicum L.) is well-known as a versatile industrial crop having various usages and contains 50-55% oil, 20% protein, 14-20% carbohydrate and 2-3% fiber. Several environmental factors are known to adversely affect yield and productivity of sesame. Our overall aim was to improve the growth, yield and quality of sesame cv. TS-3 using plant growth promoting rhizobacteria (PGPR) and saving the nitrogen and phosphate fertilizers (NP) by 50%. Field experiment (randomized complete block design) was conducted during the months of July to October of two consecutive years 2012-2013. Azospirillum (AL) and Azotobacter (AV) were applied as seed inoculation alone as well as along with half of the recommended dose of nitrogen (N) and phosphate (P) fertilizers (urea and diammonium phosphate) at the rate of 25 kg/ha and 30 kg/ha respectively. RESULTS: Here we report that A. lipoferum along with half dose of NP fertilizers (ALCF) were highly effective in increasing the agronomic and yield traits of sesame as compared to the control. A. vinelandii plus NP fertilizers (AVCF) exhibited higher seed oil content. Minimum acid value, optimum specific gravity and modified fatty acid composition were observed in ALCF treatment. Increase in oleic acid by ALCF is directly linked with improved oil quality for health benefits as oleic acid is the fatty acid which creates a balance between saturation and unsaturation of oil and for the hypotensive (blood pressure reducing) effects. CONCLUSION: It is inferred that ALCF treatment improved plant growth, seed yield and oil quality of sesame pertaining to good quality edible oil production.

Structural characterization and applications of a novel polysaccharide produced by Azospirillum lipoferum MTCC 2306.

Azospirillum lipoferum MTCC 2306, a free-living nitrogen fixing bacteria, has a doubling time of 1.7 h in MPSS media. At the end of 28 h at a pH of 7 and temperature of 30 °C it produces 1.8 ± 0.013 g/L biomass and 2.1 ± 0.018 g/L of cyclic beta glucan (CßG) in MPSS medium with a yield coefficient (YP/S) of 2.1. This novel polysaccharide is a water-soluble cyclic biopolymer and is generally produced by Rhizobiaceae and predominantly made up of glucose. The CßG has a degree of polymerisation varying between 10 and 13 and has both α- and ß-glycosidic linkages. It is not substituted with any functional groups such as acetates or succinates. Its ability to bind to aniline blue suggests that it can be a potential candidate for being used as carrier in medical imaging as well as in reducing toxicity of textile effluents. It is able to encapsulate rifampicin, a hydrophobic drug and increase its aqueous solubility by 71%. So, CßG appears to have promising applications in the field of drug, food, cosmetic and nutraceutical industries.

[Effect of flavonoids on the composition of surface glycopolymers in Azospirillum lipoferum Sp59b].

Cultivation of the type strain Azospirillum lipoferum Sp59b in the presence of the flavonoid quercetin induced modification of the structure of the bacterial lipopolysaccharide. Cultivation in the presence of the flavonoid was shown to result in altered serological characteristics of the bacteria, increased heterogeneity of the outer membrane lipopolysaccharide pool, as well as in modified composition and fatty acid ratio of lipid A. The flavonoid was shown to induce the synthesis of the O-specific polysaccharide with the repeating structure represented by a tetrasaccharide consisting of a linear trisaccharide fragment of α-L-Rhap residues in the main chain and the terminal ß-D-Glcp residue. The structure of this O-specific polysaccharide was identical to the previously determined structure of the capsular polysaccharide of these bacteria grown without quercetin. Modifications in the structural composition of the capsular polysaccharide induced by cultivation in the presence of quercetin were revealed.

Capsular polysaccharide of the bacterium Azospirillum lipoferum Sp59b: structure and antigenic specificity.

Antigenic differences were revealed between the cell wall outer membrane lipopolysaccharides and the capsular high molecular weight bioglycans for a typical strain of the nitrogen-fixing rhizobacterium Azospirillum lipoferum Sp59b using antibodies prepared against the homologous lipopolysaccharide and lipopolysaccharide-protein complex. From the capsular lipopolysaccharide-protein and polysaccharide-lipid complexes of A. lipoferum Sp59b, polysaccharides were isolated and their structure was for the first time established in Azospirillum by monosaccharide analysis which included determination of the absolute configurations, methylation, O-deacetylation, and one- and two-dimensional NMR spectroscopy. The polysaccharides of the capsular complexes were shown to have identical structure of the branched tetrasaccharide repeating unit, which differs from the structure of the O-specific polysaccharide within the outer membrane lipopolysaccharide of this strain.

Synthesis of a tetrasaccharide related to the O-antigen from Azospirillum lipoferum SR65.

Concise synthesis of a tetrasaccharide repeating unit of the LPS isolated from Azospirillum lipoferum SR65 has been accomplished through suitable protecting group manipulations and stereoselective glycosylation starting from commercially available L-rhamnose and D-glucose. The target oligosaccharide in the form of its p-methoxyphenyl glycoside is suitable for further glycoconjugate formation via selective cleavage of the OMP glycoside. Plant growth-promoting bacteria (PGPB) of genus Azospirillum plays important roles in the growth and development of plants. The interaction between the roots of the plants and the microbes is governed by the cell surface carbohydrate polymers (CPS, LPS, etc.). The present synthetic-based study elucidates aspects of plant-microbe interaction and future biofertiliser design.

Revised structure of the repeating unit of the O-specific polysaccharide from Azospirillum lipoferum strain SpBr17.

A neutral O-polysaccharide liberated by mild acid hydrolysis of a lipopolysaccharide isolated from Azospirillum lipoferum SpBr17 was investigated using 1D and 2D (1)H and (13)C NMR spectroscopy, including HSQC, HMBC, and NOESY as well as SDS-PAGE electrophoresis along with sugar and methylation analyses. The structure of the O-specific polysaccharide repeating unit was established as follows: [Formula: see text]. The presented structure is a revised version of the formula that was published earlier in the Abstracts of the 9th International Congress on Nitrogen Fixation in Cancun (Mexico, 1992).

Structural analysis of the O-antigen of the lipopolysaccharide from Azospirillum lipoferum SR65.

A neutral O-polysaccharide was obtained by mild acid degradation of the lipopolysaccharide isolated by phenol/water extraction from the asymbiotic diazotrophic rhizobacterium Azospirillum lipoferum SR65. The following structure of the O-polysaccharide was established by composition and methylation analyses, Smith degradation, and (1)H and (13)C NMR spectroscopy, including a 2D ROESY experiment: formula see text.

Characterization of a novel lipid A structure isolated from Azospirillum lipoferum lipopolysaccharide.

The structure of lipid A from Azospirillum lipoferum, a plant-growth-promoting rhizobacterium, was investigated. It was determined by chemical analysis, mass spectrometric methods, as well as 1D and 2D NMR spectroscopy. Because of the presence of substituents, the investigated lipid A differs from typical enterobacterial lipid A molecules. Its backbone is composed of a beta-(1,6)-linked D-glucosamine disaccharide but lacks phosphate residues. Moreover, the reducing end of the backbone (position C-1) is substituted with alpha-linked d-galacturonic acid. 3-hydroxypalmitoyl residues are exclusively connected to amino groups of the glucosamine disaccharide. Hydroxyls at positions C-3 and C-3' are esterified with 3-hydroxymyristic acids. Primary polar fatty acids are partially substituted by nonpolar fatty acids (namely, 18:0, 18:1 or 16:0), forming acyloxyacyl moieties.

Structure of the O-polysaccharide from the Azospirillum lipoferum Sp59b lipopolysaccharide.

A neutral O-specific polysaccharide was obtained by mild acid hydrolysis of the lipopolysaccharide of the plant-growth-promoting bacterium Azospirillum lipoferum Sp59b. On the basis of sugar and methylation analyses along with 1D and 2D (1)H and (13)C NMR spectroscopy, including a NOESY experiment, the following structure of the branched hexasaccharide repeating unit of the O-polysaccharide was established: [carbohydrate structure: see text].