Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.1 (alkaline phosphatase)
 47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

IP-10 is a member of the chemokine family of cytokines and is induced in a variety of cells in response to interferon gamma and lipopolysaccharide. The self-aggregation common to many chemokines, including IP-10, has hindered the identification of a specific IP-10 receptor. Using an IP-10 alkaline phosphatase fusion protein that fortuitously blocks this self-aggregation, we have identified an IP-10 binding site on a variety of cells including endothelial, epithelial, and hematopoietic cells. This binding site has a Kd of 25 nM, is inhibited by recombinant murine or human IP-10, and is dependent on the presence of cell surface heparan sulfate proteoglycans (HSPG). This conclusion is based on the findings that IP-10 binding to cells is: (a) inhibited by heparin and heparan sulfate; (b) sensitive to a 1 M NaCl wash; (c) eliminated by treatment with heparinase and trypsin; and (d) absent on mutant CHO cells that do not express cell surface HSPG. Platelet factor 4 (PF4), but not IL-8, monocyte chemoattractant protein-1, RANTES, monocyte inflammatory protein (MIP)-1 alpha, or MIP-1 beta, can compete effectively with IP-10 for binding to the cell surface. Furthermore, IP-10 shares with PF4 the ability to inhibit endothelial cell proliferation (IC50 = 150 nM). These studies demonstrate specificity in the interaction of chemokines and HSPG, and they define IP-10 and PF4 as a distinct subset of chemokines sharing an HSPG-binding site and angiostatic properties.
 ...
PMID:The IP-10 chemokine binds to a specific cell surface heparan sulfate site shared with platelet factor 4 and inhibits endothelial cell proliferation. 779 Aug 18

We investigated the reaction of the popliteal lymph nodes (PLN) to the injection of two antigens, keyhole limpet hemocyanin (KLH) and lipopolysaccharide (LPS), into the footpads of rats, as well as the changes occurring in the PLN after allogeneic cell stimulation. Changes in alkaline phosphatase (ALP) activity of the lymph nodes were examined enzyme histochemically. Paralleling with PLN weight gain, increased ALP activity was observed in the medullary regions of the lymph nodes of stimulated rats. ALP reactivity in the stimulated lymph nodes was observed to be weak in the germinal centers and strong in the medullary regions. The spleens of rats subjected to systemic graft-vs.-host (GVH) reaction were examined in a similar fashion. The ALP-positive areas of the GVH spleens increased in size as compared with normal spleens. These positive areas of lymph node and spleen appear to correspond mainly to areas containing OX12-positive cells. These results suggest that enzyme-histochemical analysis of ALP activity together with immunohistochemical analysis of lymphocyte phenotypes may be a useful method for examining lymph node and spleen reactions to soluble and cellular antigens in rats.
 ...
PMID:Changes in the distribution and intensity of alkaline phosphatase activity in rat lymph node and spleen cells after antigen stimulation. 787 94

The periplasm of Neisseria gonorrhoeae should be similar to other Gram-negative bacteria, but no published reports confirm this assumption. We used a periplasmic isolation procedure developed in Escherichia coli to release the periplasmic contents of N. gonorrhoeae. The resultant periplasmic extract lacked lipopolysaccharide, protein markers of inner or outer membranes, surface-radiolabelled protein components, or ribosomal proteins. The periplasmic extract contained a single haem protein believed to be a c-type cytochrome known to exist in the periplasm of other Gram-negative species, and retained significant alkaline phosphatase activity. The dominant protein species released in the periplasmic extract was the gonococcal homologue of elongation factor Tu, a major component released in similar periplasmic extracts of E. coli. These data showed that the extraction procedure selectively released periplasmic components and that the gonococcal periplasm was comparable to that of E. coli. Further analysis of the gonococcal periplasm may provide important insights into the physiology of this pathogen of humans.
 ...
PMID:Isolation of the periplasm of Neisseria gonorrhoeae. 796 34

The expression of alkaline phosphatase (APase) activity by purified B cells from lipopolysaccharide (LPS)-hyporesponsive C3H/HeJ mice was determined. Optimal APase activity was expressed after costimulation with interleukin-5 and dextran sulfate (DXS), whereas LPS, which is highly effective on B lymphocytes from normal mice, was unable to induce enzyme expression, even in the presence of DXS. The simultaneous determination by flow cytometry of both cellular APase, by using a fluorescent azo dye technique, and DNA content showed that APase was highly expressed by about one-tenth of cells in G1 phase, whereas it was present in more than 50% of cells in S and G2/M phases. The enzyme, as visualized by confocal microscopy after cell sorting on the basis of DNA content, was found to be localized mainly in vesicular structures distributed throughout the cytoplasm in G1 cells. It was distributed in patches and essentially localized at the cell periphery in S cells, whereas clear capping of activity was observed in G2/M cells.
 ...
PMID:Expression and visualization during cell cycle progression of alkaline phosphatase in B lymphocytes from C3H/HeJ mice. 818 40

Salmonella abortusovis is a pathogenic bacterium highly specific to sheep, causing spontaneous abortion. In order to understand the role of genes involved in pathogenicity, we investigated S. abortusovis with the random mutagenic TnphoA transposon. A total of 95 S. abortusovis TnphoA mutants yielding alkaline phosphatase active fusion protein were obtained. In this way we created a bank of strains in order to identify any phenotypic modification which could affect the periplasmic and/or exported proteins involved in virulence. The TnphoA mutants were screened for the ability to adhere to epithelial cells: a total of 23 mutant strains lost this phenotypic feature. To detect the chromosomal TnphoA insertions, DNA was restricted by the enzyme EcoRV, which does not cleave the TnphoA sequence. Southern blotting analysis revealed the existence of four classes of integration. Colonies of adhesiveless mutants appear to be as smooth as the S. abortusovis wild type, and electrophoretic analysis indicates a normal lipopolysaccharide profile. To identify mutations affecting genes encoding for outer membrane proteins (OMPs), the alkaline phosphatase portion of the fusion proteins was revealed in TnphoA mutants by immunoblotting with specific antibodies. A mutation in OMPs was detected in seven mutants. Restriction analysis identified in four mutants a common region of 2 kb where alterations in genes coding for OMPs occur. We suggested that this region is involved in pathogenicity in mice, since a group of mutant strains has shown reduced virulence in mice and one mutant is completely avirulent. Furthermore, after mice were exposed orally to these mutants, significant protection against oral challenge with the parental virulent strain resulted.
 ...
PMID:TnphoA Salmonella abortusovis mutants unable to adhere to epithelial cells and with reduced virulence in mice. 838 3

This study was performed to clarify the mechanisms underlying post-resection changes in liver cell proliferation and metabolism. To assess the role of gut-derived endotoxaemia and endogenous cytokines in these changes, the effects of peri-operative treatment with either the lipopolysaccharide-neutralizing bactericidal/permeability-increasing protein or interleukin-1 receptor antagonist were investigated at 24 h after two-thirds hepatectomy in rats. Peri-operative treatment with either agent caused enhanced expression of proliferating cell nuclear antigen (PCNA) and reduced lipid accumulation. Activity of the hexose monophosphate shunt was significantly decreased after partial hepatectomy and restored by interleukin-1 receptor antagonist only. After partial hepatectomy, bile canalicular alkaline phosphatase activity was significantly increased in pericentral zones and redistributed to both bile canalicular and sinusoidal membranes of hepatocytes. These effects were not significantly influenced by either treatment. It is concluded that endotoxin restricts liver cell proliferation and leads to lipid accumulation following partial hepatectomy, and that interleukin-1 is a principal mediator in these processes. Furthermore, interleukin-1 mediates a repression of the pentose phosphate pathway. These changes may be of significance with respect to liver function, at least in the early phase after partial hepatectomy.
 ...
PMID:Endotoxin- and cytokine-mediated effects on liver cell proliferation and lipid metabolism after partial hepatectomy: a study with recombinant N-terminal bactericidal/permeability-increasing protein and interleukin-1 receptor antagonist. 869 33

Escherichia coli of the serotype O157:H7 is an enterohemorrhagic human pathogen which demonstrates attaching and effacing adhesion to colonocytes in vivo and to epithelial cells grown in tissue culture. Transposon TnphoA mutants of E. coli O157:H7 strain CL-8 were produced. Two of 300 alkaline phosphatase positive mutants, designated JB6 and JB27, did not express O157 side chains as assessed by agglutination with specific polyclonal O157 antiserum, silver staining of lipopolysaccharide extracts separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and Western immunoblots with polyclonal O157-specific antiserum. Both O157-negative mutants and the parent strain demonstrated localized adherence to HEp-2 cells when examined by Giemsa staining and bright-field microscopy. Furthermore, both O157-negative mutants showed enhanced adherence to HEp-2 cells compared with the parent strain when assessed by quantification of adherent bacterial CFUs. The parent strain, CL-8, and both of the mutants produced fluorescent foci when adherent bacteria and HEp-2 cells were stained with fluorescein isothiocyanate-labelled phalloidin. Transmission electron microscopy confirmed attaching and effacing adherence of strain CL-8 and the OO7-negative mutants to HEp-2 cells. These findings indicate that mutants deficient in O157 polysaccharide repeats exhibit adherence to tissue culture cells in vitro and that O157 polysaccharide repeats are not required to produce the attaching and effacing lesion.
 ...
PMID:Polysaccharide side chains are not required for attaching and effacing adhesion of Escherichia coli O157:H7. 875 53

The paracrystalline surface layer (S-layer) of Caulobacter crescentus is composed of a single protein (RsaA, 1026 amino acids) that associates noncovalently with the lipopolysaccharide of the outer membrane. Like many other extracellular proteins of Gram-negative bacteria, the S-layer protein is not processed during transport to the cell surface. To study the secretion of RsaA, several N-terminal deletions of the protein were made by modifying the 5'-region of the rsaA gene. This analysis showed that portions of the N-terminus totalling the first 775 N-terminal amino acids (75% of the protein) could be removed from RsaA without abolishing secretion of the remainder of the protein. Although the RsaA N-terminus was not required for secretion, an N-terminal domain consisting of either 34 or 52 RsaA-derived amino acids promoted export of the alkaline phosphatase reporter (PhoA) and a cellulase reporter (delta CenA) from the cytoplasm; using the cellulase reporter, the efficiency of hybrid protein export was estimated at 9%. No enzyme activity was detected in the cell-free culture fluids as the result of expressing any gene fusion, indicating that no hybrid protein was completely secreted from the cell. RsaA:PhoA hybrid proteins were also exported from the E. coli cytoplasm, a bacterium not expected to contain the necessary machinery for the secretion of RsaA. Taken together, these data indicate that the secretion pathway of RsaA relies on a C-terminal secretion signal and that once separated from the context of the native protein, the extreme N-terminus of RsaA can act as an inefficient cryptic export signal that is not used during native RsaA secretion.
 ...
PMID:The extreme N-terminus of the Caulobacter crescentus surface-layer protein directs export of passenger proteins from the cytoplasm but is not required for secretion of the native protein. 876 82

Tissue injury is a common occurrence in multiple organ failure, a possible clinical complication of Gram-negative bacterial sepsis. Gram-negative bacteria, in part through lipopolysaccharide (LPS), tumor necrosis factor, and other cytokines, activate neutrophils to increase oxygen consumption and produce reactive oxygen species (ROS). ROS have been suggested to play a critical role in the pathogenesis of multiple organ failure. Accordingly, we hypothesized that the susceptibility of tissues to ROS can be reduced by augmenting the antioxidant status of the affected tissues. Rats were challenged intravenously with LPS (Escherichia coli: 0111:B4) at a dose of 1 mg/kg body weight, and 0, 2, 4, or 6 h later were treated intravenously with plain liposomes or alpha-tocopherol liposomes (20 mg alpha-tocopherol/kg body weight); treated rats were then killed 24 h after LPS challenge. Animals challenged with LPS were extensively damaged in the liver, as evidenced by an increase in plasma alanine aminotransferase and aspartate aminotransferase activities, and also in the lung, as indicated by a decrease in pulmonary angiotensin-converting enzyme and alkaline phosphatase activities. The injection of LPS also resulted in increased myeloperoxidase activities in the two organs, suggestive of activation of the inflammatory response. Within the pulmonary and hepatic organs of LPS-challenged animals, the involvement of oxidative stress mechanisms was evident, because a significant decrease in reduced glutathione and an increase in lipid peroxidation were observed. In contrast, the administration of alpha-tocopherol liposomes in the post-LPS-challenge period resulted in a significant alleviation of both lung and liver injuries, evidenced by a general reversal of the altered biochemical indices toward normal among treated animals. The therapeutic effect was found to be greater when liposomal alpha-tocopherol treatment was given earlier during the development of injury. Plain liposomes administered immediately after LPS injection also protected hepatic and pulmonary tissues from injuries. However, unlike alpha-tocopherol liposomes, plain liposomes did not confer any beneficial effect when administered at later timepoints post-LPS injection. These data suggest that alpha-tocopherol, administered in a liposomal form, may serve as a potentially effective pharmacological agent in the treatment of LPS-induced tissue injuries.
 ...
PMID:Treatment of LPS-induced tissue injury: role of liposomal antioxidants. 882 99

Immunohistochemistry was used to study the kinetics of B lymphocytes (B-lys) in the early stages of the localized inflammatory response induced in SMA mice by the subcutaneous injection of lipopolysaccharide (LPS). At the injection sites, medium-sized B-lys formed early inflammatory lesions with neutrophils and activated macrophages on days 1 and 2. The B-lys were morphologically similar to monocytes, but were not stained with Mac1 antibody. Remarkably the B-lys showed the phenotypes of B220+, IgM+, IgD (slight to negative), Ly-1- and CD23- by double immunohistochemical staining. The B-lys were also positive for alkaline phosphatase. Consequently the B-lys could be identified as monocytoid B-lys or marginal zone B-lys. Plasmacytic B-lys and plasma cells were first observed on days 3 and 4, but no lymphoid follicles were found at the injection sites. In the inguinal lymph nodes, the same B-lys responses were mainly induced in the paracortical lesions (T cell areas) preceding the formation of activated germinal centers (GC). These findings suggested that the B-lys, induced by injections of LPS, matured into plasma cells in the localized inflammatory lesions independent of GC, and that they were different from follicular B-lys.
 ...
PMID:Kinetics of monocytoid B lymphocytes in localized inflammatory lesions induced by lipopolysaccharide in mice. 886 91


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