Calcofluor- and lectin-binding exocellular polysaccharides of Azospirillum brasilense and Azospirillum lipoferum

Gallo, Maddalena Del; Negi, Makoto; Neyra, Carlos A.

doi:10.1128/jb.171.6.3504-3510.1989

Cited by 119 publications

(130 citation statements)

References 37 publications

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“…Previously published data support the hypothesis that EPS is involved in aggregation of Axospirillum (Sadasivan & Neyra, 1985;Del Gallo et al, 1989;Michiels et al, 1990;Arunakumari et al, 1992;Katupitiya et al, 1995 ;Pereg-Gerk et al, 1998 ;Burdman et al, 1998). We propose that under certain growth conditions, protein(s) from the outer membrane could interact with EPS, leading to aggregation and flocculation.…”

Section: Involvement Of Omps In Aggregationsupporting

confidence: 66%

Involvement of outer-membrane proteins in the aggregation of Azospirillum brasilense

et al. 1999

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A bioassay was developed t o investigate biological factors involved in the aggregation of Azospirillum brasilense strain Cd. Cells were grown for 24 h under aggregation-inducing and non-aggregation-inducing conditions (high and low C:N, respectively) and sonicated for 20 s. The cells were washed by centrifugation and resuspended in potassium phosphate buffer containing the two types of sonication extract. A greater extent of aggregation and higher flocculation were observed after 2-3 h incubation in the presence of sonicates from cells grown a t high C:N (H-cells) compared to cells grown at low C:N. Flocculation did not occur after incubation of these cells in phosphate buffer. Boiled or proteinase K-treated sonicates originating from H-cells had lower aggregation-inducing capacity. After fractionation of the crude sonicate, both the outer-membrane protein (OMP) and the total membrane (mostly OMP) fractions possessed relatively high aggregation specific activities. The aggregation-inducing capacity of the OMP fraction strongly correlated with its protein concentration in the bioassay. Treatment of this fraction with proteinase K also decreased its aggregation-inducing activity. These findings suggest that OMPs are involved in the aggregation process of cells of A. brasilense.1

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Section: Involvement Of Omps In Aggregationsupporting

confidence: 66%

Involvement of outer-membrane proteins in the aggregation of Azospirillum brasilense

et al. 1999

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“…Furthermore, fructose plays a major role in aggregation by enhancing polysaccharide synthesis (Kaci et al, 2005;Sadasivan and Neyra, 1985) and this polysaccharide induce flocculation by bridging of polymers between the cells (Del Gallo et al, 1989). All Methylobacterium strains were found to be positive for Calcoflour staining as evidenced by the positive fluorescence.…”

Section: Discussionmentioning

confidence: 99%

EPS Production, PHB Accumulation and Abiotic Stress Endurance of Plant Growth Promoting Methylobacterium Strains Grown in a High Carbon Concentration

Woo¹,

Subramanian²,

Krishnamoorthy

et al. 2012

Korean Journal of Soil Science and Fertilizer

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In this study, we compared growth pattern, floc yield, Exo-polysaccharides (EPS) production, Poly-β -hydroxybutyrate (PHB) accumulation, resistance to osmotic and acid stress in Methylobacterium strains CBMB20, CBMB27, CBMB35, and CBMB110. Modified high C:N ratio medium denoted as HCN-AMS medium was used with a C:N ratio of 30:1. The HCN-AMS medium favored increased growth in all the studied strains. All Methylobacterium strains tested positive for EPS production and showed positive fluorescence with calcoflour stain. Elevated levels of EPS production from 4.2 to 75.0% was observed in HCN-AMS medium. Accumulation of PHB in HCN-AMS medium increased by 3.8, 36.7, and 12.0% in strains CBMB27, CBMB35, and CBMB110 respectively. Among the abiotic stresses, osmotic stress-induced growth inhibition of Methylobacterium strains was found to be lowered when grown in HCN-AMS medium. Likewise, growth inhibition due to acid stress at pH 5.0 was lower for strains grown in HCN-AMS medium compared to growth in AMS medium. Enhanced survivability under stress conditions may be attributed to the high EPS and PHB production at increased carbon concentration in the growth medium.

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“…Direct staining with dyes: Staining with Alcian Blue (8GX; Sigma) and the fluorochrome calcofluor (Fluorescent Brightener 28; Sigma) was performed following the protocols of Logan et al (1994) and Del Gallo et al (1989), respectively.…”

Section: Methodsmentioning

confidence: 99%

“…The staining procedure was performed with formaldehyde-preserved as well as non-preserved samples. Alternatively, staining of smears air-dried on microscope slides was attempted (original protocol by Del Gallo et al 1989).…”

Section: Staining With Fluorescein Isothiocyanate (Fitc)-labelled Lecmentioning

confidence: 99%

“…A modification of the procedure outlined by Del Gallo et al (1989) was used for staining the exopolymers with FITC-labeled lectins (Sigma) ( Table 2). Samples of bacteria were filtered on 0.2 µm pore-size black polycarbonate filters, washed with phosphate-buffered saline (PBS), covered for 30 min with 3 ml of lectin solution (100 µg ml -1 in PBS), washed again with PBS, and finally stained with DAPI.…”

Section: Staining With Fluorescein Isothiocyanate (Fitc)-labelled Lecmentioning

confidence: 99%

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Exopolymer production and microcolony formation by planktonic freshwater bacteria: defence against protistan grazing

Hahn¹,

Lünsdorf²,

Janke³

2004

Aquat. Microb. Ecol.

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The defence mechanisms of 2 novel bacterial isolates against protistan grazing were investigated in experiments with batch and continuous cultures. Strains MWH55 and MWH73 were isolated from the plankton of mesotrophic lakes using culture conditions with strong flagellate grazing pressure. The analysis of their 16S rRNA genes revealed that both strains belong to the Betaproteobacteria and demonstrated a close phylogenetic relatedness to bacteria previously detected by culture-independent methods in river biofilms and lake snow aggregates. Both strains showed a very weak sensitivity to flagellate predation, and both formed planktonic microcolonies that exceeded the upper size limit for ingestion by flagellates, and were thus protected from predation. These microcolonies consisted of cells embedded in a common exopolymeric matrix, yet lacked direct cell-to-cell contact between neighbouring cells. The structure of the exopolymeric matrix of the microcolonies was visualized by electron microscopy, while detection of exopolysaccharides by several fluorescently labeled lectins failed. The matrix possessed a complex 3-dimensional structure with strainspecific characteristics. Currently, it is not clear whether the 2 isolates possess a planktonic life strategy or whether they switch between sessile (biofilm or lake snow aggregates) and planktonic dispersal stages. In both cases, however, a low sensitivity of the planktonic stages to protistan predation is ecologically advantageous. The ability to form an exopolymeric matrix enabling the formation of predation-protected microcolonies is assumed to play a key role in the ecology of these bacteria.

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Calcofluor- and lectin-binding exocellular polysaccharides of Azospirillum brasilense and Azospirillum lipoferum

Cited by 119 publications

References 37 publications

Involvement of outer-membrane proteins in the aggregation of Azospirillum brasilense

Involvement of outer-membrane proteins in the aggregation of Azospirillum brasilense

EPS Production, PHB Accumulation and Abiotic Stress Endurance of Plant Growth Promoting Methylobacterium Strains Grown in a High Carbon Concentration

Exopolymer production and microcolony formation by planktonic freshwater bacteria: defence against protistan grazing

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