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E K Moses

Publications and source records attributed to E K Moses.

28 records · Page 2Linked to original sources
PubMed1998

Gene expression of plasminogen activation cascade components in human term gestational tissues with labour onset.

The plasminogen activation cascade is thought to play a critical role in labour-associated remodelling events, such as fetal membrane rupture and placental separation. The aim of this study was to quantify, by Northern analysis, the gene expression of urokinase plasminogen activator (UPA), urokinase receptor (UPAR) and plasminogen activator inhibitor type-2 (PAI-2) in human gestational tissues. Amnion, choriodecidua and placenta were collected from women before, during and after spontaneous-onset labour at term. The expression of UPAR mRNA was significantly (P < 0.05) increased in amnion tissue during and after labour and delivery, compared with the before-labour group. In contrast, UPAR gene expression in choriodecidua and placenta was not significantly altered in association with labour onset. PAI-2 mRNA expression was also significantly (P < 0.05) increased in amnion after labour. No statistically significant differences were observed in choriodecidua or placenta PAI-2 mRNA with labour onset. Neither was any significant effect of labour status on UPA mRNA identified in any of the tissues examined. This study is the first to describe a significant increase in UPAR and PAI-2 gene expression in human amnion tissue with labour. These data are consistent with the hypothesis that, during labour, up-regulation of UPAR expression in amnion serves to localize active UPA at the cell surface, thereby increasing proteolytic activity in fetal membranes. Increased PAI-2 in amnion after labour may provide a regulatory 'switch' to cease further proteolysis in this tissue type. In conclusion, the data obtained support the proposal that the plasminogen activation cascade contributes to the rupture of fetal membranes during active labour.

Amnion↗
PubMed1997

Antigens for serological diagnosis of ovine footrot.

An antigen extracted from Dichelobacter nodosus with potassium thiocyanate (KSCN) is currently used in enzyme-linked immunosorbent assay (ELISA) for serological diagnosis of ovine footrot, but the test lacks specificity in mature sheep. Other antigens were therefore evaluated for use in this test. Structural components of the cell envelope of D. nodosus including outer membrane, cytoplasmic membrane, lipopolysaccharide and pilus and extracellular proteases were purified from cultured D. nodosus while recombinant membrane proteins, protease and pilus antigens were also evaluated. Many antigenic components of D. nodosus participated in reactions in ELISA that were not specific for infection with D. nodosus and apart from pilus, none of the antigens resulted in improved specificity of the ELISA. Using a positive-negative cut-off to yield sensitivity of 70%, ELISA using pili from cultured D. nodosus serogroup A had a specificity of 98.3% compared with 89.7% for the ELISA with KSCN-extract as antigen (P < 0.001). Recombinant pili morphogenetically expressed in Pseudomonas aeruginosa were unsuitable for use in ELISA due to copurification of Pseudomonas antigens to which apparently healthy sheep directed antibodies. The application of ELISA with D. nodosus pilus as antigen in footrot control programs is discussed.

Animals↗
PubMed1997

Differential expression of type II, IV and cytosolic PLA2 messenger RNA in human intrauterine tissues at term.

The involvement of phospholipase A2 (PLA2) enzymes in the formation of biologically-active phospholipid metabolites by human gestational tissues has principally been characterized by the use of enzyme activity assays. While such assays have established the presence of functional PLA2 activity, there is a paucity of information concerning the tissue distribution and relative contribution to net activity made by specific PLA2 isozymes. In particular, both secretory and cytosolic isozymes may be involved in gestational tissue phospholipid metabolism. Thus, the aim of this study was to test the hypothesis that phospholipase A2 mRNA transcripts encoding Type II, Type IV and cytosolic PLA2 are tissue-specifically expressed in human amnion, choriodecidua and placenta obtained at term. The relative expression of polyA+ mRNA encoding these PLA2 isozymes was determined by Northern blot analysis and laser densitometry. The data obtained confirm the tissue-specific expression of PLA2 mRNA in human intrauterine tissues. Cytosolic PLA2 mRNA was most abundantly expressed in amnion when compared to either choriodecidua (which was 5-fold less than amnion; P < 0.001) or placenta (72-fold less than amnion; P < 0.001). In contrast, the secretory PLA2 mRNA transcripts (i.e. Type II and Type IV) were most abundantly expressed in placenta. Type II PLA2 mRNA expression in choriodecidua and amnion was 30-fold less than that observed in placenta (both P < 0.001). Type IV PLA2 mRNA expression was 37-fold (P < 0.001) and 73-fold (P < 0.001) less in choriodecidua and amnion respectively. These data support the conclusion that cytosolic PLA2 is the principal PLA2 isozyme mediating phospholipid metabolism and the liberation of fatty acid substrate (i.e. arachidonic acid) in term amnion, while secretory PLA2 isozymes, and in particular, Type II PLA2 play a major role in phospholipid metabolism in term placenta.

Amnion↗
PubMed1997

The expression of parathyroid hormone-related protein mRNA and immunoreactive protein in human amnion and choriodecidua is increased at term compared with preterm gestation.

Parathyroid hormone-related protein (PTHrP) gene expression and/or immunoreactive protein have previously been identified in the uterus and intrauterine gestational tissues. The putative roles of PTHrP during pregnancy include vasodilatation, regulation of placental calcium transfer, uterine smooth muscle relaxation and normal fetal development. The aims of this study were 1) to determine the tissue-specific and temporal expression of PTHrP mRNA and immunoreactive protein in human gestational tissues collected at preterm and term; and 2) to determine the effect of labour on PTHrP expression by collecting these tissues from women undergoing elective caesarean section (before labour), intra-partum caesarean section during spontaneous-onset labour (during labour), and women with spontaneous labour and normal vaginal delivery (after labour). Total RNA and protein were extracted from placenta, amnion (over placenta and reflected) and choriodecidua for analysis by Northern blot (using a specific human PTHrP cDNA probe), and by N-terminal PTHrP RIA respectively. In amnion over placenta, reflected amnion and choriodecidua both PTHrP mRNA relative abundance and immunoreactive protein were significantly elevated at term compared with preterm (P < 0.01). At term, both PTHrP and its mRNA were significantly greater in amnion than in placenta and choriodecidua (P < 0.05). Also, both PTHrP and its mRNA were significantly elevated in amnion over placenta compared with reflected amnion (P < 0.05). The expression of PTHrP and its mRNA did not change in association with term labour or rupture of the fetal membranes, therefore this study provides no evidence for a specific PTHrP role in the onset and/or maintenance of term labour. However, the significant up-regulation of PTHrP mRNA and protein in the fetal membranes at term compared with preterm suggests an important role in late human pregnancy.

Amnion↗
PubMed1996

Identification of a native Dichelobacter nodosus plasmid and implications for the evolution of the vap regions.

Studies on the role of various virulence factors of the ovine pathogen, Dichelobacter nodosus, have suffered from the absence of a mechanism for the introduction of DNA into this organism. As an initial step in the development of genetic methods, we have identified and cloned a native 10-kb plasmid, pJIR896, from a clinical isolate. This plasmid was found to be a circular form of vap region 1/3 that is found in the reference strain, A198. However, pJIR896 lacked the duplicated region present in the A198 sequence and instead contained a 1.7-kb putative insertion sequence, IS1253, which shared similarity to a number of unusual IS elements. A model is proposed for the evolution of vap region 1/3 which involves the integration of a plasmid, such as pJIR896, and subsequent rearrangements resulting from the deletion or transposition of IS1253.

Base Sequence↗
PubMed1995

A multiple site-specific DNA-inversion model for the control of Omp1 phase and antigenic variation in Dichelobacter nodosus.

The molecular cloning and sequence analysis of four structurally variant linked genes (omp1A,B,C,D) that encode the major outer membrane protein of Dichelobacter nodosus strain VCS1001 are described. The isolation of rearranged copies of omp1A and omp1B, and the identification in the 5' regions of all four genes of short cross-over-site sequences that were similar to the Din family of cross-over-site sequences, suggested that site-specific DNA inversion was involved in omp1 rearrangement. Evidence for site-specific inversion of the 497 bp DNA fragment, which was located between the divergently orientated omp1A and omp1B genes, and which contained the promoter and 5' coding sequence of Omp1, was obtained by polymerase chain reaction-mediated amplification of inverted forms of these genes. However, to account for all of the omp1 gene copies cloned in this study, a more widespread inversion phenomenon must be involved in the rearrangement of these genes and a model for multiple site-specific DNA inversions at the omp1 locus is described. In this model the four structurally variant omp1 genes can be assembled from one of four structurally variant C-terminal coding regions and a conserved N-terminal coding region and can be expressed from a single promoter. It is postulated that this genetic capability endows D. nodosus with the ability to switch the antigenic specificity of one of its major surface proteins.

Amino Acid Sequence↗
PubMed1994

Genetic organization of the duplicated vap region of the Dichelobacter nodosus genome.

The recombinant plasmid pJIR318 contains a fragment of the Dichelobacter nodosus genome which is associated with virulence. Sequence analysis of the pJIR318 insert has shown that it contains four vap (virulence-associated protein) genes which are homologous to open reading frames found on the Escherichia coli F plasmid and the Neisseria gonorrhoeae cryptic plasmid (M. E. Katz, R. A. Strugnell, and J. I. Rood, Infect. and Immun. 60:4586-4592, 1992). The plasmid pJIR318 hybridizes to three regions of the D. nodosus genome, each of which has now been isolated. Regions 1 and 3 were found to be adjacent in the genome of D. nodosus A198, and the order of the vap genes in vap regions 1 and 2 were shown to be identical. Partial sequence analysis and Southern blot analysis of the vap regions showed that the three regions probably arose by a duplication event(s) followed by insertions and/or deletions. A recombinant plasmid, pJIR749, was isolated from a library of a benign D. nodosus strain, 305. This plasmid contained sequences from both ends of vap region 2. Analysis of pJIR749 showed that the sequences on either side of vap region 2 were separated by 324 bp in the genome of benign strain 305 and that the orientations of the sequences were different. It is clear that a simple insertion or deletion event did not generate the benign and virulent strains studied. A model which describes the evolution of the duplicated vap regions in D. nodosus A198 is presented.

Bacteria, Anaerobic↗
PubMed1989

Molecular analysis of one of multiple protease-encoding genes from the prototype virulent strain of Bacteroides nodosus.

The aim of these studies was to examine the organization of the Bacteroides nodosus protease-encoding gene(s). The extracellular serine proteases (38 kDa) from the prototype virulent strain of B. nodosus were purified and used to raise a specific antiserum in rabbits. This antiserum was used in a colony immunoassay to screen a genomic DNA library constructed in Escherichia coli using BamHI-digested B. nodosus DNA and the plasmid pBR322. An E. coli clone expressing a 50-kDa immunoreactive polypeptide was identified. No protease activity was detected in the culture media, or in crude soluble and membrane fractions prepared from this clone. Restriction mapping and deletion analysis of the recombinant plasmid, pEKM2, was used to locate the coding region to a 1.4-kb EcoRI-BamHI fragment which was subsequently sequenced. A large open reading frame was found to extend through the BamHI site from a putative start codon just downstream from the EcoRI site, which indicated that the complete gene was not isolated. Southern blotting demonstrated that there were at least three B. nodosus BamHI fragments which were homologous to the 0.4-kb PstI-BamHI fragment of pEKM2. Based on these results the existence of multiple protease genes in B. nodosus was postulated.

Amino Acid Sequence↗
PubMed1983

Increased in vitro labeling of stable RNA within the rat nodose ganglion following abdominal vagotomy.

An in vitro procedure for labeling of RNA in the excised rat nodose ganglion was used to evaluate the changes in incorporation of [3H]uridine into ganglionic RNA following transection of the abdominal vagus nerves. Significant increases in the incorporation into 28S, 18S and 4S RNA were observed at 1 day after injury, which were maximal at 4 days before returning to unoperated control level by 7 days. A second transient increase in the labelling of these RNA species occurred between 9 and 11 days after injury. Comparison of the time course of these increases with those seen previously following cervical vagus nerve crush injury indicate that the time of onset of the increase in incorporation in independent of the site of injury, but that the maximal response is delayed by 1 day with the more distal lesion. These data are consistent with the existence of separate signals for initiating and modulating the cell body response to axon injury, which are transported retrogradely from the site of injury at rates exceeding the slow component of axoplasmic transport.

Animals↗