Disease relevance of Xanthan

• Xanthomonas campestris pv. campestris is grown commercially to produce the exopolysaccharide xanthan gum, which is used as a viscosifying and stabilizing agent in many industries [1].
• Use of xanthan gum in dietary management of diabetes mellitus [2].
• Compared to production by P. alginolyticus, a 30-fold increase in volumetric productivity of soluble xanthan lyase was achieved by heterologous production in E. coli [3].
• Changes in subjective sensations due to xerostomia before and after administration of Xialine, a xanthan gum-based saliva substitute, were evaluated in 30 patients with radiation-induced xerostomia using the QLQ-H&N35 [4].
• phi L7 is a lytic bacteriophage infecting Xanthomonas campestris pv. campestris, a Gram-negative bacterium producing xanthan gum and causing black rot in crucifers [5].

Psychiatry related information on Xanthan

• To minimize the effects of olfaction, texture and postingestive effects, rats were rendered anosmic with intranasal zinc sulfate, test substances were suspended in 0.3% xanthan gum solution and test fluids were offered for 5 min [6].

High impact information on Xanthan

• The extracellular polysaccharide xanthan is shown by electron microscopy to be an unbranched, probably double-stranded fiber 4 nanometers wide and 2 to 10 micrometers long when native [7].
• Other areas included microbial nutrition, strain improvement, bioconversions of statins and beta-lactams, sporulation and germination, plasmid stability, gel microdroplets, and the production of double-stranded RNA, the polymer xanthan, and enzymes (polygalacturonase, protease, cellulase) [8].
• The crystal structures of xanthan lyase and its complex with the product (pyruvylated mannose) were refined at 2.3 and 2.4 A resolution with final R-factors of 17.5 and 16.9%, respectively [9].
• Results from dialysis and fermentation predicted the action of wheat bran, pectin, guar, gum arabic, carboxymethylcellulose, gellan, tragacanth, xanthan, and karaya in humans and generated anomalous results for karaya and tragacanth [10].
• A 1:1 mixture of xanthan and locust bean gum (X/LBG) had the greatest viscosity at equivalent concentrations and shear rates and was more effective than guar gum, xanthan, or locust-bean gum at inhibiting glucose movement in vitro [11].

Chemical compound and disease context of Xanthan

• Functional characterization of GumK, a membrane-associated beta-glucuronosyltransferase from Xanthomonas campestris required for xanthan polysaccharide synthesis [12].
• Construction of lactose-utilizing Xanthomonas campestris and production of xanthan gum from whey [13].
• Sequential assembly and polymerization of the polyprenol-linked pentasaccharide repeating unit of the xanthan polysaccharide in Xanthomonas campestris [14].
• Mutations that block the synthesis of xanthan gum by Xanthomonas campestris B1459S-4L-II were isolated as nonmucoid colonies after treatment with ethyl methanesulfonate [15].
• Mutation in the Xanthomonas campestris xanA gene required for synthesis of xanthan and lipopolysaccharide drastically reduces the efficiency of bacteriophage (phi)L7 adsorption [16].

Biological context of Xanthan

• The biphasic region is substantially wider than observed for xanthan, another semirigid polyelectrolyte approximately twice as stiff as DNA, primarily because of low critical concentrations for first appearance of the anisotropic phase, C(i)*, in DNA samples > or =110 nm (320 base pairs) long [17].
• Expression of the gum operon directing xanthan biosynthesis in Xanthomonas campestris and its regulation in planta [18].
• The gum gene cluster of Xanthomonas campestris pv. campestris comprises 12 genes whose products are involved in the biosynthesis of the extracellular polysaccharide xanthan [18].
• Chromosome map of Xanthomonas campestris pv. campestris 17 with locations of genes involved in xanthan gum synthesis and yellow pigmentation [19].
• Locations of eight eps loci involved in exopolysaccharide (xanthan gum) synthesis, two rrn operons each possessing an unique I-CeuI site, one pig cluster required for yellow pigmentation, and nine auxotrophic markers were determined, using mutants isolated by mutagenesis with Tn5(pfm)CmKm [19].

Anatomical context of Xanthan

• Immune responses to xanthan gum. I. The characteristics of lymphocyte activation by xanthan gum [20].
• The xanthan-induced increase in intraluminal water in the small intestine was partially due to a slowed absorption of osmotically active substances from the gut [21].
• The amount and distribution of water, dry matter, and sugars in the digestive tract of rats fed xanthan gum [21].
• Monoclonal antibodies specific for the exopolysaccharide xanthan side chain labeled the bacteria, the fibrillar matrix, and portions of the host cell wall [22].
• Bacteria isolated from infant feces were immobilized in polysaccharide gel beads (2.5% gellan gum, 0.25% xanthan gum) using a two-phase dispersion process [23].

Associations of Xanthan with other chemical compounds

• Dilute mixed solutions of non-surface active anionic polymers (polyacrylamide and polystyrene sulfonate, xanthan) and various surfactants have been studied with several methods: surface tension, ellipsometry, X-ray and neutron reflectivity, thin film balance, surface and bulk rheology [24].
• Sequence analysis showed that the mutated gene is xanA coding for phosphoglucomutase/phosphomannomutase, required for the synthesis of lipopolysaccharide and exopolysaccharide (xanthan) [16].
• Its capacity was demonstrated using three different sulfated polysaccharides: heparin, a sulfated glucuronogalactan extracted from a red algae, and a semisynthetic xanthan sulfate [25].
• Microspheres of a polyelectrolyte complex hydrogel were prepared from chitosan and xanthan after interaction between the two polyionic polymers [26].
• The addition of xanthan gum increased flocculation of magnesium carbonate and aluminum hydroxide and apparently caused partial deflocculation of zinc oxide suspensions [27].

Gene context of Xanthan

• These experiments showed that the A. xylinum celB gene could not complement the role of the bifunctional X. campestris phosphoglucomutase-phosphomannomutase gene in xanthan biosynthesis [28].
• The recA mutation is not correlated with the frequency of occurrence of a genetic rearrangement that affects chemotaxis, plant virulence, and xanthan gum production [29].
• Evidence for a role for the gumB and gumC gene products in the formation of xanthan from its pentasaccharide repeating unit by Xanthomonas campestris [30].
• A subclone of the gum gene cluster carrying gumB and gumC restored xanthan production to strain 8397 to levels approximately 28% of the wild-type [30].
• The Xanthomonas campestris gumD gene required for synthesis of xanthan gum is involved in normal pigmentation and virulence in causing black rot [31].

Analytical, diagnostic and therapeutic context of Xanthan

• Polysaccharide lyase: molecular cloning, sequencing, and overexpression of the xanthan lyase gene of Bacillus sp. strain GL1 [32].
• The in vitro synthesis of pentasaccharide-P-P-polyprenol was also accompanied by the incorporation of radioactivity into a polymeric product, which was characterized as xanthan, on the basis of gel filtration and permethylation studies [14].
• From the observation of the distribution behavior of suppositories in rabbit rectum and colon after the rectal administration, xanthan gum was found to prevent the upward spread of the drug [33].
• Improvement in bioreactor productivities using free radicals: HOCl-induced overproduction of xanthan gum from Xanthomonas campestris and its mechanism [34].
• Intracellular compounds quantification by means of flow cytometry in bacteria: application to xanthan production by Xanthomonas campestris [35].

References