Structural analysis of an acidic polysaccharide secreted by Xanthobacter sp. (ATCC 53272)

O’Neill, Malcolm A.; Darvill, Alan G.; Albersheim, Peter; Chou, Kechia J.

doi:10.1016/0008-6215(90)80068-e

Cited by 23 publications

(7 citation statements)

References 16 publications

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“…The secretion of polysaccharides, typical of the genus Xanthobacter (25,37), enhances cell attachment and aggregation, and a thin biofilm developed on the wall during reactor operation even though the system was vigorously stirred. However, this did not affect microbial analysis, since the biofilm was continuously sloughing from the wall and being mixed back into the biomedium.…”

Section: Resultsmentioning

confidence: 99%

Stability and Performance of Xanthobacter autotrophicus GJ10 during 1,2-Dichloroethane Biodegradation

Baptista

Peeva

Zhou

et al. 2006

Appl Environ Microbiol

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A nucleic acid-based approach was used to investigate the dynamics of a microbial community dominated by Xanthobacter autotrophicus GJ10 in the degradation of synthetic wastewater containing 1,2-dichloroethane (DCE). This study was performed over a 140-day period in a nonsterile continuous stirred-tank bioreactor (CSTB) subjected to different operational regimens: nutrient-limiting conditions, baseline operation, and the introduction of glucose as a cosubstrate. The microbial community was analyzed by a combination of fluorescence in situ hybridization (FISH) and denaturing gradient gel electrophoresis (DGGE). Under nutrientlimiting conditions, DCE degradation was restricted, but this did not affect the dominance of strain GJ10, determined by FISH to comprise 85% of the active population. During baseline operation, DCE degradation improved significantly to over 99.5% and then remained constant throughout the subsequent experimental period. DGGE profiles revealed a stable, complex community, while FISH indicated that strain GJ10 remained the dominant species. During the addition of glucose as a cosubstrate, DGGE profiles showed a proliferation of other species in the CSTB. The percentage of strain GJ10 dropped to 8% of the active population in just 5 days, although this did not affect the DCE biodegradation performance. The return to baseline conditions was accompanied by the reestablishment of strain GJ10 as the dominant species, suggesting that this system responds robustly to external perturbations, both at the functional biodegradation level and at the individual strain level.

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Section: Resultsmentioning

confidence: 99%

Stability and Performance of Xanthobacter autotrophicus GJ10 during 1,2-Dichloroethane Biodegradation

Baptista

Peeva

Zhou

et al. 2006

Appl Environ Microbiol

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“…, 1967). Partially methylated alditol acetates were analysed using temperature programme E. Determination of the linkage position of Kdo required reduction of the methylated carboxyl group with 200 μl of Superdeuteride ® (Aldrich) at room temperature for 2 h before sample hydrolysis (O´Neil et al. , 1990).…”

Section: Methodsmentioning

confidence: 99%

Structural characterization of lipo‐oligosaccharide (LOS) from Yersinia pestis: regulation of LOS structure by the PhoPQ system

Hitchen¹,

Prior²,

Oyston³

et al. 2002

Molecular Microbiology

101

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Structural characterization of lipo-oligosaccharide (LOS) fromYersinia pestis: regulation of LOS structure by the PhoPQ system to alter LOS structure may be required for survival of Y. pestis within the mammalian and/or flea host. IntroductionYersinia pestis, the aetiological agent of bubonic plague, is a member of the Enterobacteriaceae, its closest relative being the enteropathogen Yersinia pseudotuberculosis, from which it has probably evolved (Achtman et al., 1999). Plague is primarily a disease of rodents with enzootic foci throughout the world (Perry and Fetherston, 1997). Humans are accidental hosts, with transmission usually occurring through the bite of an infected flea (Gage, 1998). Upon injection into a new host, many of the bacilli are phagocytosed by polymorphonuclear leukocytes or macrophages. Bacteria within the polymorphonuclear leukocytes are killed, whereas those within macrophages are carried to the regional lymph nodes draining the site of infection (Perry and Fetherston, 1997). Multiplication in the lymph node gives rise to a bubo, the classical symptom of infection, followed by dissemination to produce a bacteraemia. If the infection progresses to involve the lungs, pneumonic plague develops (Perry and Fetherston, 1997). Pneumonic plague is highly infectious and rapidly fatal and is thus of great public health concern.From the infected rodent reservoir, through the flea vector and the mammalian intracellular and extracellular phases of infection, Y. pestis encounters diverse and hostile environments. Bacteria closely regulate the expression of their genes in response to environmental conditions to optimize survival. They must be able to monitor specific environmental parameters and modulate gene expression appropriately. This regulation is frequently controlled at the transcriptional level by a twin superfamily of sensor and regulator proteins (Hoch and Silhavy, 1995). One of these two-component regulatory systems, the PhoPQ system, has been identified in Y. pestis (Oyston et al., 2000). The PhoPQ two-component signal transduction system has been studied most closely in Salmonella enterica var Typhimurium (Groisman, 2001). In Salmonella, PhoQ monitors extracellular Mg 2+ levels (Garcia-Vescovi et al., 1996) and activates PhoP to control the expression of over 40 proteins, including some required for virulence (Miller et al., 1989 SummaryThe two-component regulatory system PhoPQ has been shown to regulate the expression of virulence factors in a number of bacterial species. For one such virulence factor, lipopolysaccharide (LPS), the PhoPQ system has been shown to regulate structural modifications in Salmonella enterica var Typhimurium. In Yersinia pestis, which expresses lipooligosaccharide (LOS), a PhoPQ regulatory system has been identified and an isogenic mutant constructed. To investigate potential modifications to LOS from Y. pestis, which to date has not been fully characterized, purified LOS from wild-type plague and the phoP defective mutant were analysed by mass spectrometry. Here...

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“…Later analysis of the DNA sequences resolved the latter group into two distinct contiguous genes: spsC and spsE. The spsG mutations (11,43,71,81, and 104) were complemented by the c6 clone and the B12.6 segment. Insertional mutagenesis of the B12.6 segment yielded plasmids Y652, Y635, Y636, Y653, Y640, and Y641.…”

Section: Cloning Of Genes Essential For Sphingan S-88 Biosynthesismentioning

confidence: 99%

“…The group includes S-88, S-60 (gellan), S-130 (welan), S-194 (rhamsan), heteropolysaccharide 7,41,43). As diagrammed in Fig.…”

mentioning

confidence: 99%

Linkage of genes essential for synthesis of a polysaccharide capsule in Sphingomonas strain S88

Yamazaki¹,

Thorne²,

Mikolajczak³

et al. 1996

J Bacteriol

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Several structurally related capsular polysaccharides that are secreted by members of the genus Sphingomonas are being developed as aqueous rheological control agents for diverse industrial and food applications. They include gellan (S-60), welan (S-130), rhamsan (S-194), S-657, S-88, S-198, S-7, and NW-11. We refer to these polysaccharides as sphingans, after the genus name. This paper characterizes the first gene cluster isolated from a Sphingomonas species (S88) that is required for capsule synthesis. Overlapping DNA segments which spanned about 50 kbp of S88 DNA restored the synthesis of sphingan S-88 in capsule-negative mutants. The mutations were mapped into functional complementation groups, and the contiguous nucleotide sequence for the 29-kbp cluster was determined. The genetic complementation map and the DNA sequences were interpreted as an extended multicistronic locus containing genes essential for the assembly and secretion of polysaccharide S-88. Many of the deduced amino acid sequences were similar to gene products from other polysaccharide-secreting bacteria such as Rhizobium meliloti (succinoglycan), Xanthomonas campestris (xanthan gum), and Salmonella enterica (O antigen). The S88 locus contained a four-gene operon for the biosynthesis of dTDP-L-rhamnose, an essential precursor for the sphingans. Unexpectedly, there were also two genes for secretion of a lytic or toxin-like protein nested within the polysaccharide cluster. The conservation and linkage of genes that code for a defensive capsule and genes for secretion of an offensive lysin or toxin suggest a heretofore unknown pathogenic life history for Sphingomonas strain S88.The ''sphingans'' are capsular polysaccharides that have similar but not identical structures and are secreted by members of the genus Sphingomonas (44). The group includes S-88, S-60 (gellan), S-130 (welan), S-194 (rhamsan), heteropolysaccharide 7,41,43). As diagrammed in Fig. 1, the sphingans have different side groups, and either L-rhamnose or L-mannose is found at one position in the backbone. L-Mannose itself is exceedingly rare in nature. Aqueous solutions of the polymers have unique and useful rheological properties (41). Gellan is currently produced by large-scale aerobic fermentation for use as a gelling agent in foods and microbiological culture media, and welan is marketed for control of aqueous viscosity. It is not clear how the structural variations in the polymers give rise to distinct rheological properties.Sphingomonas strains have been isolated from diverse environments and with a wide range of metabolic activities. The sphingan-secreting strains were isolated from plant tissue, water, and soil. Chemoheterotrophic strains with the ability to metabolize toluene, naphthalene, cresol, and other aromatic compounds were recently isolated from deep terrestrial subsurface sediments (12). And other strains have been studied for their ability to degrade lignin (38). Sphingomonas bacteria have also been isolated from human clinical specimens and from hospital wate...

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Structural analysis of an acidic polysaccharide secreted by Xanthobacter sp. (ATCC 53272)

Cited by 23 publications

References 16 publications

Stability and Performance of Xanthobacter autotrophicus GJ10 during 1,2-Dichloroethane Biodegradation

Stability and Performance of Xanthobacter autotrophicus GJ10 during 1,2-Dichloroethane Biodegradation

Structural characterization of lipo‐oligosaccharide (LOS) from Yersinia pestis: regulation of LOS structure by the PhoPQ system

Linkage of genes essential for synthesis of a polysaccharide capsule in Sphingomonas strain S88

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