Disease relevance of rhamnose

• A L-rhamnose transport-negative strain of Escherichia coli was generated by Mu d(ApR,lac)I mutagenesis [1].
• After a 10-day recovery period, rats received a single intraperitoneal injection of saline or PG-PS (25 microg rhamnose/gm body weight) [2].
• The platelet aggregation-associated protein (PAAP) from Streptococcus sanguis contains 39% carbohydrate in rhamnose-rich polysaccharides [3].
• The genes were individually expressed in Streptomyces albus and also coexpressed with genes involved in the biosynthesis of l-rhamnose, the 6-deoxysugar attached to the elloramycin aglycon [4].
• The L-rhamnose-H+ symporter (RhaT) is a 344-amino acid integral membrane protein, found in many Enterobacteria, which couples the uptake of the sugar L-rhamnose with the inward movement of protons [5].

High impact information on rhamnose

• This response was dependent on an optimal cell density (2 X 10(6) cells/ml), on the presence of antigen, it was specific and cross-reactive due to a shared rhamnose backbone of the two polysaccharide antigens, and it was highly selective, such that in a 42-55-day culture 1 out of 20 viable cells was a specific PFC [6].
• METHODS: Twenty-six patients undergoing coronary artery bypass grafting underwent an intestinal absorption-permeability test involving ingestion of 3-O-methyl-D-glucose, D-xylose, L-rhamnose, and lactulose [7].
• It is postulated that reduced L-rhamnose urinary excretion in untreated villous atrophy is due to a decreased absorptive area in the small bowel, whereas increased lactulose excretion indicates leakiness of the abnormal mucosa to larger polar molecules [8].
• Deoxythymidine diphosphate (dTDP)-L-rhamnose is the precursor of L-rhamnose, a saccharide required for the virulence of some pathogenic bacteria. dTDP-L-rhamnose is synthesized from glucose-1-phosphate and deoxythymidine triphosphate (dTTP) via a pathway involving four distinct enzymes [9].
• Glycosidase treatment or acid hydrolysis of HIF released only L-rhamnose, the hexose isomer found in ouabain, as detected by chiral GC/MS [10].

Chemical compound and disease context of rhamnose

• The glycan is a tetraheteroglycan from the cell wall of Streptococcus faecalis, strain N and is composed of glucose, galactose, rhamnose, N-acetylgalactosamine, and phosphate [11].
• The serotype-specific polysaccharide antigen of Actinobacillus actinomycetemcomitans Y4 (serotype b) consists of D-fucose and L-rhamnose [12].
• CONCLUSIONS: Graft versus host disease is associated with an increase in the lactulose to rhamnose clearance ratio reflecting an increase in host bowel permeability [13].
• Patients with Crohn's disease (n = 28) and 32 first degree relatives from 11 families underwent a polyethylene glycol 400 (PEG400) intestinal permeability test and a hyperosmotic (1500 mosmol/l) absorption/permeability test using 3-0-methyl-D-glucose, D-xylose, L-rhamnose, lactulose, and 51chromium labelled ethylenediamine-tetraacetate [14].
• The signs of graft versus host disease, including splenomegaly and altered intestinal mucosal architecture, as well as the increased lactulose to rhamnose ratio were significantly attenuated in small bowel transplant animals treated with cyclosporine A (10 mg/kg/day) [13].

Biological context of rhamnose

• In the absence of 3-O-methylation, further methylation of GPL rhamnose is apparently inhibited, and overall GPL synthesis is down-regulated by 90% [15].
• L-rhamnose is an essential component of the cell wall and plays roles in mediating virulence and adhesion to host tissues in many microorganisms [16].
• The most effective saccharide in the hemagglutination inhibition assay for both STL1 and STL2 was L-rhamnose [17].
• These derivatives were formed through reductive amination of p-nitrophenyltriazene (NPT) ethylenediamine to the periodate-oxidized rhamnose moiety of ouabain [18].
• In this phytopathogenic bacterial species, RhaS positively regulates the transcription of the rhaBAD operon, involved in rhamnose catabolism, of the rhiE gene and of the rhiTN operon [19].

Anatomical context of rhamnose

• Lactulose is considered a marker of unmediated paracellular (tight junction) permeation, while L-rhamnose explores passage across cell membranes [20].
• The inhibitory effect of STIF on the DNA synthesis was not blocked by addition of a sugar (alpha-methyl-D-mannoside, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, L-fucose, or L-rhamnose) in culture, as determined by using rat bone marrow cells [21].
• Approximately 50% of the galactose, glucose, and mannose present in the cytoplasmic membrane was found in lipid extracts, while the remainder of these sugars and 98% of the rhamnose were present as nonlipid sugars [22].
• Like SISS-B, a soluble suppressive lymphokine present in the supernatants of Con A-activated peripheral blood T cell cultures, CTC-SISS-B is of 60,000 to 90,000 m.w., and its action is blocked by the simple sugar L-rhamnose [23].
• Activation of human monocytes by streptococcal rhamnose glucose polymers is mediated by CD14 antigen, and mannan binding protein inhibits TNF-alpha release [24].

Associations of rhamnose with other chemical compounds

• There was 85.4%, 85.5%, and 73.6% reduction (P < 0.01) in active (3-O-methyl-D-glucose) and passive (D-xylose) carrier-mediated transport and passive, nonmediated transcellular (L-rhamnose) transport in the immediate postoperative period, respectively [7].
• In the present study, determination of absolute configuration by gas chromatography of the trimethylsilyl (+)-2-butyl glycosides revealed that the rhamnose residues were of the L configuration while the hexoses were all D [25].
• Residents in tropical areas had a higher mean lactulose:rhamnose ratio and lower mean five hour recoveries of 3-0-methyl-D-glucose, D-xylose, and L-rhamnose, indicating higher intestinal permeability and lower absorptive capacity [26].
• The transcription activator VirF is a member of a new family of regulators including those of the arabinose and rhamnose operons as well as a regulator of enteric colonization pili [27].
• The effect of altering O-antigen chain length on S. flexneri virulence was investigated by inserting a kanamycin (Km)-resistance cassette into the rol gene (controlling the modal O-antigen chain length distribution), and into the rfbD gene, whose product is needed for synthesis of dTDP-rhamnose (the precursor of rhamnose in the O-antigen) [28].

Gene context of rhamnose

• The sequencing of the EcoRI-HindIII fragment complementing mutations in the structural genes of the L-rhamnose regulon of Escherichia coli has permitted identification of the open reading frames corresponding to rhaB, rhaA, and rhaD [29].
• The structural gene, rhaT, encoding the rhamnose permease has been cloned from Escherichia coli. rhaT has been mapped in the rha locus (87.7 min) by analysis of cotransduction with glpK and other rha markers [30].
• Protein products of 47 kDa, 52-54 kDa and 32 kDa have been assigned to rhamnose isomerase, rhamnulose kinase and rhamnulose 1-phosphate aldolase respectively [31].
• The precise location of the rhaT gene, encoding rhamnose permease, has been established between sodA and rhaC at 3605-3607 kb of Kohara's physical map, which corresponds to 88.4 min on the Escherichia coli chromosomal map [32].
• Glucose-1-phosphate thymidylyltransferase is the first enzyme in the biosynthesis of dTDP-l-rhamnose, the precursor of l-rhamnose, an essential component of surface antigens, such as the O-lipopolysaccharide, mediating virulence and adhesion to host tissues in many microorganisms [33].
• These results suggested that the LRA1-4 genes encode L-rhamnose 1-dehydrogenase, L-rhamnono-gamma-lactonase, L-rhamnonate dehydratase, and L-KDR aldolase, respectively, by which L-rhamnose is converted into pyruvate and L-lactaldehyde through analogous reaction steps to the ED pathway [34].

Analytical, diagnostic and therapeutic context of rhamnose

• Comparison of the therapeutic efficacy of the conjugates against the MX-1 xenograft tumor implanted s.c. in nude mice showed that conjugates of derivatives missing the rhamnose, a sugar residue that is part of the DNA binding region of the drug, were not as promising as antitumor therapies [35].
• Two L-rhamnose-binding lectins named STL1 and STL2 were isolated from eggs of steelhead trout (Oncorhynchus mykiss) by affinity chromatography and ion exchange chromatography [17].
• We used complementation analysis and DNA mobility shift assays to show that RhaR is not the direct activator of the L-rhamnose catabolic operon, rhaBAD [36].
• DESIGN: Eleven subjects ingested 25 g l-rhamnose, lactulose, or d-glucose (control) for 28 d in a partially randomized crossover design [37].
• In addition, scanning electron microscopy of the seed surface indicated a distorted testa morphology, illustrating not only a structural but also a developmental role for RGI or rhamnose metabolism in proper testa formation [38].

References