Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A lipopolysaccharide was isolated from Pseudomonas aurantiaca IMB 31 by extraction with aqueous phenol and purified by ultracentrifugation. The lipopolysaccharide was confined to the phenol phase. Fucosamine (2-amino-2,6-dideoxygalactose) (36%) and bacillosamine (2,4-diamino-3,4,6-trideoxyglucose) (23%) were identified as hypothetic components of the O-chain in the carbohydrate moiety of the macromolecule using the techniques of paper chromatography, gas-liquid chromatography and ion-exchange chromatography on an amino acid analyser. Rhamnose, glucose, galactose, glucosamine and galactosamine were detected as hypothetical components of the core in the lipopolysaccharide composition, as well as 2-keto-3-deoxyoctonic acid, heptose, alpha-alanine and phosphorus, usual components of the core in Pseudomonas. The following predominant fatty acids were identified in the composition of lipid A using the techniques of gas-liquid chromatography with standard compounds and gas-liquid mass spectrometry: 3-OH C10:0 (14.4%), C12:0 (30.5%), 2-OH C12:0 (14.9%), 3-OH C12:0 (17.4%), C16:0 (9.9%). The serological relationship between P. aurantiaca strains was studied, and their phylogenetic relationship with P. fluorescens is discussed.
 ...
PMID:[Immunochemical characteristics of a lipopolysaccharide from Pseudomonas aurantiaca]. 324 96

Many clinically useful antibacterial drugs have intracellular target sites. Therefore, in order to reach their targets, these compounds must be able to cross bacterial outer and cytoplasmic membranes. Considerable information is available on the mechanisms by which antibiotics cross bacterial membranes and, in many cases, it is now possible to define the molecular basis of their uptake. Passage of drugs across the outer membrane of Gram-negative bacteria can occur by diffusion through porin channels (e.g. beta-lactams and tetracyclines), by facilitated diffusion using specific carriers (e.g. albomycin), or by self-promoted uptake (e.g. aminoglycosides and polymyxins). Transfer of antibiotics across the bacterial cytoplasmic membrane is usually mediated by active, carrier-mediated, transport systems normally operating to transport essential solutes into the cell. For example, the antibiotic streptozotocin bears sufficient structural resemblance to N-acetyl-D-glucosamine to be transported by the phosphoenolpyruvate:phosphotransferase system, and D-cycloserine is recognized by the D-alanine, proton motive force dependent transport system. However, in some cases (e.g. tetracycline) although carrier-mediated transport is implied by the observation that drug uptake is energy dependent, the nature of the membrane carrier(s) responsible is unknown. Knowledge acquired from studies on bacterial peptide transport has been successfully used to deliver (or smuggle) amino acid mimetics disguised as peptides into the bacterial cell. These amino acid mimetics, although often poorly transported in their own right, are frequently potent inhibitors of bacterial peptidoglycan or lipopolysaccharide synthesis once they have gained access to the interior of the cell.
 ...
PMID:Molecular mechanisms involved in the transport of antibiotics into bacteria. 328 90

The horseshoe crab clotting factor, factor C, present in the hemocytes is a serine-protease zymogen activated with lipopolysaccharide. It is a two-chain glycoprotein (Mr = 123,000) composed of a heavy chain (Mr = 80,000) and a light chain (Mr = 43,000) [T. Nakamura et al. (1986) Eur. J. Biochem. 154, 511-521]. In our continued study of this zymogen, we have now also found a single-chain form of factor C (Mr = 123,000) in the hemocyte lysate. The heavy chain had the NH2-terminal sequence of Ser-Gly-Val-Asp-, consistent with that of the single-chain factor C, indicating that the heavy chain is derived from the NH2-terminal part of the molecule. The light chain had an NH2-terminal sequence of Ser-Ser-Gln-Pro-. Incubation of the two-chain zymogen with lipopolysaccharide resulted in the cleavage of a Phe-Ile bond between residues 72 and 73 of the light chain. Concomitant with this cleavage, the A (72 amino acid residues) and B chains derived from the light chain were formed. The complete amino acid sequence of the A chain was determined by automated Edman degradation. The A chain contained a typical segment which is similar in sequence to a family of repeats in human beta 2-glycoprotein I, complement factors B, protein H, C4b-binding protein, and coagulation factor XIII b subunit. The NH2-terminal sequence of the B chain was Ile-Trp-Asn-Gly-. This chain contained the serine-active site sequence-Asp-Ala-Cys-Ser-Gly-Asp-Ser-Gly-Gly-Pro-. These results indicate that horseshoe crab factor C exists in the hemocytes in a single-chain zymogen form and is converted to an active serine protease by hydrolysis of a specific Phe-Ile peptide bond.
 ...
PMID:Lipopolysaccharide-sensitive serine-protease zymogen (factor C) of horseshoe crab hemocytes. Identification and alignment of proteolytic fragments produced during the activation show that it is a novel type of serine protease. 330 57

A serum-free medium has been developed which is able to support primary antibody responses by cultured murine lymphocytes. This medium is based on RPMI 1640 that is supplemented with beta-cyclodextrin, insulin, transferrin, albumin, low density lipoprotein, putrescine and L-alanine as substitutes for fetal calf serum. Omission of anyone of these components resulted in a marked decrease of antibody responses. By employing the serum-free culture conditions, it was clearly demonstrated that polyamines such as putrescine, spermidine and spermine had positive effects on the development of antibody-forming cells. This serum-free medium supported the antibody response to sheep erythrocytes, trinitrophenyl (TNP)-Ficoll or TNP-lipopolysaccharide as efficiently as 10% fetal calf serum-containing medium. In addition, murine lymphocytes proliferated in response to an antigen or a mitogen equally well in these two types of medium.
 ...
PMID:Development of a serum-free medium for in vitro immune responses by using beta-cyclodextrin. Demonstration of the requirements for polyamines. 341 28

The chemical constitutional analysis of the lipopolysaccharide (LPS) isolated from Providencia rettgeri was carried out. Polyacrylamide gel electrophoresis using sodium dodecylsulfate or sodium deoxycholate showed that the lipopolysaccharide mostly consisted of short sugar chains. The lipid A was precipitated out after mild acid hydrolysis of LPS. From the supernatant degraded polysaccharide and unsubstituted core fractions were isolated. Compositional analysis of the core material revealed the presence of galacturonic acid, galactose, glucose, glucosamine, L-glycero-D-manno-heptose, 3-deoxy-D-manno-octulosonic acid, alanine and phosphorus. Methylation analysis of the core material indicated the presence of terminal units of glucose, galacturonic acid and glucosamine. The chemical structure of the lipid A was elucidated. It constitutes a beta-1,6-glucosamine disaccharide substituted on either side by ester and glycosidically-bond phosphate residues. The ester-bound phosphate was found to be substituted by a 4-amino-4-deoxy-L-arabinosyl residue. The amino groups of the backbone disaccharide are N-acylated by 3-O-(14:0)14:0 and 3-O-14:0. Two hydroxyl groups of the disaccharide are esterified by 3-O-(14:0)14:0 and 3-O-14:0. The taxonomical importance of these structural details will be discussed.
 ...
PMID:Lipopolysaccharide of Providencia rettgeri. Chemical studies and taxonomical implications. 352 98

Cysteine and cystine transport activities of resting and activated mouse spleen lymphocytes were characterized in order to examine the contributions of cysteine and cystine to intracellular glutathione contents. Following stimulation with lipopolysaccharide, the lymphocytes markedly increased their capacity to transport cysteine. The uptake of cysteine was mediated mainly by the ASC system (Na+-dependent neutral amino acid transport system especially reactive with alanine, serine, and cysteine). On the other hand, both the resting and the activated lymphocytes had extremely low cystine transport activities. Because of the instability of cysteine, the culture media usually contained cystine but not cysteine. Therefore, both the resting and the activated lymphocytes rapidly decreased their glutathione contents owing to their poor capacities to take up cystine. The effects of freshly added cysteine on the cellular glutathione contents were examined in the presence of bathocuproinedisulfonate, a nontoxic copper-specific chelator that inhibits autoxidation of cysteine. Cysteine added at 25-400 microM only partially prevented the rapid decrease of the glutathione contents in fresh resting lymphocytes. In the lipopolysaccharide-activated cells, however, cysteine enhanced the cellular glutathione contents in a dose-dependent manner. These results indicate that the enhanced activity of the ASC system increases the level of intracellular glutathione in the presence of cysteine.
 ...
PMID:Regulation of glutathione levels in mouse spleen lymphocytes by transport of cysteine. 368 Mar 92

Lipophilic derivatives of muramylpeptides, namely N alpha-(N-acetylmuramyl-L-alanyl-D-isoglutaminyl)-N epsilon-stearoyl-L-lysine [MDP-Lys (L18)] and 6-O-(2-tetradecylhexadecanoyl)-MDP (B30-MDP), were demonstrated to significantly enhance anti-bovine serum albumin (BSA) antibody production when they were incorporated in liposomes with BSA and administered by gastric intubation to BALB/c mice on days 0 and 1 (the primary immunization) and on days 27 and 28 (booster). N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) itself showed negligible activity under the same experimental conditions. A stearoyl derivative of sodium beta-N-acetylglucosaminyl-(1-4)-N-acetylmuramyl- L-alanyl-D-isoglutaminyl-(L)-stearoyl(D)-meso-diaminopimelic acid-(D)-amide-D-alanine (GM-53) that was isolated by enzymatic degradation of L. plantarum cell wall peptidoglycans showed a powerful adjuvant effect by oral administration in liposomes with BSA. Similar or stronger adjuvant effects were observed by oral administration of LPS preparations, KO3 LPS isolated from K. pneumoniae (a noncapsulated mutant, LEN-1), Bacto lipopolysaccharide W derived from E. coli (O127:B8) and BIOSTIM F1 fraction derived from K. pneumoniae (O1:K2). Liposomes as a vehicle for oral administration were not always required for the manifestation of the adjuvant effects of MDP-Lys (L18) and BIOSTIM F1. These compounds, but not B30-MDP, showed a powerful adjuvant effect when orally administered with BSA in phosphate buffered saline.
 ...
PMID:Enhancement of serum antibody production in mice by oral administration of lipophilic derivatives of muramylpeptides and bacterial lipopolysaccharides with bovine serum albumin. 370 42

Lipophilic derivatives of muramyl peptides, namely N alpha-(N-acetylmuramyl-L-alanyl-D-isoglutaminyl)-N epsilon-stearoyl-L-lysine [MDP-Lys (L18)] and 6-O-(2-tetradecylhexadecanoyl) -MDP (B30-MDP) were demonstrated to significantly enhance anti-bovine serum albumin (BSA) antibody production when they were incorporated in liposomes with BSA and administered by gastric intubation to BALB/c mice on days 0 and 1 (the primary immunization) and on days 27 and 28 (booster). N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) itself showed negligible activity under the same experimental conditions. A stearoyl derivative of sodium beta-N-acetylglucosaminyl-(1-4)-N-acetylmuramyl-L-alanyl-D-isoglutaminyl (D)-meso-diaminopimelic acid-(D)-amide-D-alanine (GM-53) that was isolated by enzymatic degradation of L. plantarum cell wall peptidoglycans also showed a powerful adjuvant effect by oral administration in liposomes with BSA. Similar or stronger adjuvant effects were observed by oral administration of bacterial lipopolysaccharide (LPS) preparations, KO3 LPS isolated from K. pneumoniae (a noncapsulated mutant, LEN-1), Bacto lipopolysaccharide W derived from. E. coli (O127:B8) and BIOSTIM F1 fraction derived from K. pneumoniae (O1:K2) Liposomes as a vehicle for oral administration were not always required for the manifestation of the adjuvant effects of MDP-Lys (L18) and BIOSTIM F1. These compounds, but not B30-MDP, showed a powerful adjuvant effect when orally administered with BSA in phosphate buffered saline.
 ...
PMID:Enhancement of serum antibody production in mice by oral administration of lipophilic derivatives of muramyl peptides and bacterial lipopolysaccharides with bovine serum albumin. 371 72

Natural and synthetic adjuvants of microbial origin were compared for their capacity to potentiate the induction of experimental autoimmune thyroiditis (EAT) with the autoantigen mouse thyroglobulin (MTg). Regardless of the immunomodulator used, severe thyroiditis was observed only in EAT-susceptible strains of the k haplotype and not in EAT-resistant strains of the d haplotype. Compared to phenol-extracted lipopolysaccharide, a potent adjuvant for enhancing EAT induction, phthalyl-substituted, detoxified lipopolysaccharide, even at doses 15- to 50-fold greater, led to only low anti-mouse thyroglobulin titers and mild thyroid infiltration. The synthetic adjuvant N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) and three of its analogs, N-acetylmuramyl-L-alanyl-D-isoglutamine-L-alanyl-D-glycerol mycolate (MDP-L-Ala-Glyc-Myc), N-acetylmuramyl-L-alanyl-D-glutamyl-(decyl)methyl ester [MDP(decyl)methyl], and N-acetylmuramyl-L-alanyl-D-glutamine-alpha n-butyl ester [MDP-(Gln)-OnBu], designated murabutide, were tested in incomplete Freund adjuvant or in saline. In incomplete Freund adjuvant, MDP-L-Ala-Glyc-Myc was inefficient in inducing EAT, murabutide induced very mild involvement, and MDP and, more so, MDP(decyl)methyl were active but to a lesser degree than CFA. When saline was used, low levels of thyroid infiltration were observed in a few of the MDP-treated animals in only one experiment, whereas no lesions were observed when murabutide was used.
 ...
PMID:Effects of natural or synthetic microbial adjuvants on induction of autoimmune thyroiditis. 383 8

Lipoteichoic acids (LTAs) were chromatographically purified from crude phenol-water extract of whole cells of some streptococcal species, which included Streptococcus pyogenes Sv, Streptococcus mutans 6715, and Streptococcus sanguis ATCC 10556. Among these, special attention was paid to S. pyogenes LTA for analyses of chemical composition and biological activities. All LTA preparations contained equimolar amounts of glycerol and phosphorus. Chemical analyses showed that S. pyogenes LTA contained glycerophosphate, alanine, glucose, and fatty acids (as palmitic acid) at molar ratio of 1 : 0.1 : 0.1 : 0.25. The crude phenol-water extract and isolated LTA from S. pyogenes Sv were found to be mitogenic for spleen cells of BALB/c and BALB/c (nu/nu) mice, but not for thymus cells of BALB/c mice. The mitogenicity of deacylated LTA (dLTA) was significantly lower than that of LTA. It was also found that various LTA preparations possessed polyclonal B cell activation ability and adjuvant activity both in vivo and in vitro, as demonstrated by using hemolytic plaque assay. LTA, but not dLTA, induced macrophage activation which resulted in tumor cytotoxicity in mice. Limulus lysate activity of S. pyogenes LTA was approximately 1,000 fold lower than that of Escherichia coli lipopolysaccharide. These results indicate that streptococcal LTA possesses various immunobiological activities that modulate lymphoreticular system in vivo and in vitro.
 ...
PMID:Chemical properties and immunobiological activities of streptococcal lipoteichoic acids. 389 80


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>