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Biomedical subjects

S Egan

Publications and source records attributed to S Egan.

At least 19 recordsLinked to original sources
PubMed2006

Inhibition of fungal colonization by Pseudoalteromonas tunicata provides a competitive advantage during surface colonization.

The marine epiphytic bacterium Pseudoalteromonas tunicata produces a range of extracellular secondary metabolites that inhibit an array of common fouling organisms, including fungi. In this study, we test the hypothesis that the ability to inhibit fungi provides P. tunicata with an advantage during colonization of a surface. Studies on a transposon-generated antifungal-deficient mutant of P. tunicata, FM3, indicated that a long-chain fatty acid-coenzyme A ligase is involved in the production of a broad-range antifungal compound by P. tunicata. Flow cell experiments demonstrated that production of an antifungal compound provided P. tunicata with a competitive advantage against a marine yeast isolate during surface colonization. This compound enabled P. tunicata to disrupt an already established fungal biofilm by decreasing the number of yeast cells attached to the surface by 66% +/- 9%. For in vivo experiments, the wild-type and FM3 strains of P. tunicata were used to inoculate the surface of the green alga Ulva australis. Double-gradient denaturing gradient gel electrophoresis analysis revealed that after 48 h, the wild-type P. tunicata had outcompeted the surface-associated fungal community, whereas the antifungal-deficient mutant had no effect on the fungal community. Our data suggest that P. tunicata is an effective competitor against fungal surface communities in the marine environment.

Antifungal Agents↗
PubMed2001

Identifying and prioritizing gaming workers' health and safety concerns using mapping for data collection.

BACKGROUND: This research was prompted by the clinical presentation of workers from a variety of gaming occupations with injuries and illnesses and multiple health and safety concerns. METHODS: Using participatory action research principles, 51 gaming workers in Ontario and 20 gaming workers in Manitoba were consulted during a series of focus group sessions. Mapping exercises were used to survey the participants about their health concerns, perceived occupational hazards and the impact of working conditions on their personal lives. Participants were then asked to prioritize their concerns and make recommendations for improvements. RESULTS: Gaming workers from both provinces identified similar health, hazard and psycho-social concerns. They prioritized the issues of stress, ergonomics, indoor air quality (including second-hand smoke and temperature), biological hazards, physical hazards and noise. CONCLUSIONS: This study points to a need to more fully investigate and address health and safety issues in the gaming industry. It also demonstrates the effectiveness of a worker-driven, participatory consultation.

Adult↗
PubMed2001

Phylogeny of Streptomyces species and evidence for horizontal transfer of entire and partial antibiotic gene clusters.

The phylogenetic relationships of a collection of streptomycete soil isolates and type strains were resolved by sequence analysis of trpB, a housekeeping gene involved in tryptophan biosynthesis. The analysis confirmed that two isolates were recipients in a gene transfer event, demonstrated by phylogenetic incongruency between trpB and strB1 trees. One strain had acquired the entire streptomycin biosynthetic cluster, whilst the other contained only strRAB1, the resistance gene and two flanking genes from the cluster. Sequence analysis of trpB, as part of a polyphasic approach, was a useful tool in determining intra-generic relationships within the genus Streptomyces.

Bacterial Proteins↗
PubMed2001

Pseudoalteromonas ulvae sp. nov., a bacterium with antifouling activities isolated from the surface of a marine alga.

A dark-purple marine bacterium that inhibits the germination of marine algal spores and the settlement of invertebrate larvae has been characterized and assessed for taxonomic assignment. Two strains, designated UL12T and UL13, were isolated from the surface of the common marine alga Ulva lactuca. Based on 16S rDNA sequencing, UL12T and UL13 were found to show the highest similarity (97%) to members of the genus Pseudoalteromonas. DNA-DNA hybridization studies demonstrated less than 28% genomic DNA relatedness between these isolates and closely related Pseudoalteromonas species and greater than 65% homology between UL12T and UL13. The two isolates were found to display identical characteristics and are strict aerobes, motile by means of single polar flagella, exhibit non-fermentative metabolism and require sodium ions for growth. The isolates hydrolyse gelatin and can utilize citrate, maltose, mannose and glucose but not trehalose, sucrose, fructose, lactose or glycerol as sole carbon sources. The molecular evidence together with the phenotypic characteristics show that this bacterium constitutes a new species within the genus Pseudoalteromonas. The name Pseudoalteromonas ulvae sp. nov. is proposed for this bacterium and the type strain is UL12T (= UNSW 095600T = NCIMB 13762T).

Animals↗
PubMed2001

Inhibition of algal spore germination by the marine bacterium Pseudoalteromonas tunicata.

A collection of 56 bacteria isolated from different surfaces in the marine environment were assayed for their effects on the germination of spores from the common green alga Ulva lactuca. Thirteen bacterial isolates were shown to inhibit spore germination. Of these bacteria, Pseudoalteromonas tunicata displayed the most pronounced effects against algal spores. Further characterisation of the anti-algal activity of P. tunicata was performed and it was found that this bacterium produces an extracellular component with specific activity toward algal spores that is heat-sensitive, polar and between 3 and 10 kDa in size. This biologically active compound was also found to prevent the germination of spores from the red alga Polysiphonia sp. and, given the widespread occurrence of P. tunicata in a range of marine habitats, this may suggest that it is effective against a variety of marine algae.

Journal Article↗
PubMed2001

Dietary exposures to persistent organic pollutants.

As one of the main components of risk assessment, exposure assessment plays a key role in evaluating risk. Many different scenarios can be developed to estimate the risk from exposure to chemicals such as persistent organic pollutants (POPs). The US Food and Drug Administration (FDA)'s Center for Food Safety and Applied Nutrition (CFSAN) is primarily interested in POPs as humans may be exposed to these compounds through food. Examples of POPs found in food include dioxins, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers, and some pesticide chemicals. This overview discusses various sources of data that CFSAN has used to estimate dietary exposure to POPs, and provides an example of a recent calculation of an estimate for dietary exposure for consumers in the USA to dioxins in the food supply.

Diet↗
PubMed2000

Molecular cloning and expression analysis of a mouse UDP-GlcNAc:Gal(beta1-4)Glc(NAc)-R beta1,3-N-acetylglucosaminyltransferase homologous to Drosophila melanogaster Brainiac and the beta1,3-galactosyltransferase family.

We have isolated a murine cDNA coding for a beta1,3-N-acetylglucosaminyltransferase enzyme ( beta3GnT). This enzyme is similar in sequence to Drosophila melanogaster Brainiac and to the murine and human beta1,3-galactosyltransferase family of proteins. The mouse beta 3GnT protein is 397 amino acids in length and contains 7 cysteine residues that are conserved in the human orthologue. beta 3GnT is a type II membrane protein localized to the Golgi apparatus. Enzyme assays with recombinant mouse beta 3GnT reveal that it has a preference for acceptors with Gal(beta1-4)Glc(NAc) at the non-reducing termini. Proton NMR analysis of product showed incorporation of GlcNAc in beta1,3 linkage to the terminal Gal of Gal(beta1-4)Glc(beta1-O-benzyl). Northern blot analysis revealed the presence of a single 3.0[emsp4 ]kb transcript in all adult mouse and human organs tested, with highest levels in the kidney, liver, heart and placenta. The beta 3GnT gene is also expressed in a number of tumor cell lines. The human orthologue of beta 3GnT is located on chromosome 2pl5.

Amino Acid Sequence↗
PubMed2000

Phylogenetic relationship and antifouling activity of bacterial epiphytes from the marine alga Ulva lactuca.

It is widely accepted that bacterial epiphytes can inhibit the colonization of surfaces by common fouling organisms. However, little information is available regarding the diversity and properties of these antifouling bacteria. This study assessed the antifouling traits of five epiphytes of the common green alga, Ulva lactuca. All isolates were capable of preventing the settlement of invertebrate larvae and germination of algal spores. Three of the isolates also inhibited the growth of a variety of bacteria and fungi. Their phylogenetic positions were determined by 16S ribosomal subunit DNA sequencing. All isolates showed a close affiliation with the genus Pseudoalteromonas and, in particular, with the species P. tunicata. Strains of this bacterial species also display a variety of antifouling activities, suggesting that antifouling ability may be an important trait for members of this genus to be highly successful colonizers of animate surfaces and for such species to protect their host against fouling.

Animals↗
PubMed1998

EH domain-dependent interactions between Eps15 and clathrin-coated vesicle protein p95.

The endocytic protein Eps15 contains three copies of the EH domain, a protein module thought to function in protein-protein interactions. Using overlay assays with an Eps15 EH domain fusion protein, we have now identified a protein of 95 kDa (p95) as a major EH domain-binding partner in a wide variety of tissues. The amino acids asparagine-proline-phenylalanine (NPF) form the core of an EH domain-binding motif and three NPF repeats are found in the endocytic protein synaptojanin-170. We have confirmed previous studies indicating that synaptojanin-170 is an EH domain-binding protein, and have used peptide blocking experiments to demonstrate that the interaction is mediated through the NPF repeats. Interestingly, the same peptide also blocks EH domain-binding to p95. Finally, we have shown that p95 is enriched on clathrin-coated vesicles, suggesting an endocytic role for the protein. These data support an important role for EH domain-NPF motif interactions in endocytosis.

Amino Acid Sequence↗
PubMed1998

Evidence for transfer of antibiotic-resistance genes in soil populations of streptomycetes.

Phylogenetic analysis was used to evaluate the hypothesis of gene transfer in streptomycetes, many of which are antibiotic producers. The diversity and possible origins of streptomycin-resistance genes was investigated for a population of Streptomyces strains isolated from a site in Brazil where antibiotic production had previously been implicated The analysis provides compelling evidence for the transfer of these genes. Examination of other Streptomyces-type strains also reveals a scattered distribution of streptomycin producers with respect to the overall phylogeny. These results suggest that horizontal gene transfer may be an important factor in the evolution of antibiotic genes in streptomycetes.

Anti-Bacterial Agents↗
PubMed1998

Transfer of streptomycin biosynthesis gene clusters within streptomycetes isolated from soil.

Streptomyces strains isolated from soil were found to possess various numbers of genes from the streptomycin biosynthesis cluster. The strains missing genes from the cluster also lacked the ability to produce streptomycin. Two of the isolates which contain only part of the cluster are apparently recipients of a gene transfer event. The implications for the role of gene transfer in antibiotic evolution are discussed.

Chromosome Mapping↗
PubMed1996

Negative symptoms in Alzheimer's disease.

OBJECTIVE: This study was undertaken to demonstrate that negative symptoms are prominent in patients with Alzheimer's disease and are distinct from depression. METHOD: patients with Alzheimer's disease (N=24) and a group of cognitively intact older adults (N=26) were compared in terms of scores on the Scale for the Assessment of Negative Symptoms in Alzheimer's Disease. RESULTS: Negative symptoms were more severe in patients with Alzheimer's disease than in the healthy elderly comparison subjects. Among the patients with Alzheimer's disease, negative symptoms were correlated with dementia severity. CONCLUSIONS: Patients with Alzheimer's disease display little interest in self-care, work and household tasks, social and family activities, and emotional needs of others, despite an absence of depressive symptoms, positive symptoms, comorbid systemic illnesses, or medication exposure. Such negative symptoms may contribute to functional disability and thus complicate management of such patients.

Affective Symptoms↗
PubMed1996

Regulation of rat kidney mesangial cell phospholipase A2.

1. The precursor of eicosanoids is arachidonic acid, which emanates from the cleavage of the sn-2 position of phospholipids by phospholipase A2 (PLA2). Eicosanoids have diverse physiological and pathophysiological effects in the kidney. The regulation of phospholipase A2 has important implications for kidney function. 2. In the current communication we focus our attention on mesangial cell cytosolic PLA2 (cPLA2) and its regulation at the post-translational and post-transcriptional level. 3. At the post-translational level, using site directed mutagenesis of cPLA2 and a dominant negative ras, we have demonstrated that cPLA2 can be phosphorylated by mitogen activated protein (MAP-2) kinase leading to increased cPLA2 enzymatic activity. 4. At the post-transcriptional level we show that the half-life of cPLA2 mRNA in mesangial cells is significantly increased when mesangial cells are stimulated by mitogens. We further demonstrate the presence of three ATTTA motifs in the 3' untranslated region (3' UTR) of the cPLA2 cDNA. 5. Using chimeric constructs bearing the 3' UTR from rat cPLA2 fused downstream of the luciferase reporter, we demonstrate that this region exerts a destabilizing effect on cPLA2. 6. We have isolated and mapped genomic DNA and polymorphic markers for cPLA2 in the human and rat.

Animals↗
PubMed1995

Response of colon cancer cell lines to the introduction of APC, a colon-specific tumor suppressor gene.

The APC gene, mutations in which are responsible for the inherited colon cancer syndrome adenomatous polyposis coli (APC), is described as a tumor suppressor gene. A full-length, wild-type APC gene was introduced by transfection into three human colon carcinoma cell lines, each characterized for mutations at loci involved in colon tumor formation. The response of each cell line to the introduction of APC differed with the genotype of the cell line. Some of the cell clones derived from these transfections displayed altered morphologies; some showed suppression of tumorigenicity based on growth in soft agar and tumor formation in nude mice. One cell line, SW480, could not be stably transfected with the APC gene. These results provide the first direct evidence that the APC gene can alter the transformation properties of colon carcinoma cells.

Animals↗
PubMed1992

Selective medical examination at school entry: should we do it, and if so how?

A prospective study was conducted on 82 consecutive 5+ examinations performed by four school doctors over a period of two months. The aim was to assess the impact of applying selection criteria for examination. Information gathered included immunization status, history of previous developmental assessments and previous detection of problems, and the result of the examination for each child. Forty-three per cent of children were up to date with their immunizations, 66 per cent had had a six-week check and 38 per cent and 17 per cent had been assessed at 15 months and 2 1/2 years respectively. Forty-eight problems were detected in 37 children (45 per cent), of which 27 had not been previously detected. Of these, 19 were detected by the school nurse before the examination as a result of hearing (nine) and vision (10) testing and measurement of height and weight (one). Of the remaining problems, four were presented by the parent, one by the teacher and two were detected by the school doctor. If a policy of selective examination had been in place in which children were called for examination only if they had never been assessed before, or where there were no records of a previous assessment, or if their immunizations were incomplete, or they had previous problems, or the school nurse or teacher or parent had expressed concern, all but four children would have been examined. It was concluded that this particular method of selection would be unproductive and that a system whereby the school nurse was responsible for screening and selection for examination would be preferable.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1990

Human endothelial actin-binding protein (ABP-280, nonmuscle filamin): a molecular leaf spring.

Actin-binding protein (ABP-280, nonmuscle filamin) is a ubiquitous dimeric actin cross-linking phosphoprotein of peripheral cytoplasm, where it promotes orthogonal branching of actin filaments and links actin filaments to membrane glycoproteins. The complete nucleotide sequence of human endothelial cell ABP cDNA predicts a polypeptide subunit chain of 2,647 amino acids, corresponding to 280 kD, also the mass derived from physical measurements of the native protein. The actin-binding domain is near the amino-terminus of the subunit where the amino acid sequence is similar to other actin filament binding proteins, including alpha-actinin, beta-spectrin, dystrophin, and Dictyostelium abp-120. The remaining 90% of the sequence comprises 24 repeats, each approximately 96 residues long, predicted to have stretches of beta-sheet secondary structure interspersed with turns. The first 15 repeats may have substantial intrachain hydrophobic interactions and overlap in a staggered fashion to yield a backbone with mechanical resilience. Sequence insertions immediately before repeats 16 and 24 predict two hinges in the molecule near points where rotary-shadowed molecules appear to swivel in electron micrographs. Both putative hinge regions are susceptible to cleavage by proteases and the second also contains the site that binds the platelet glycoprotein Ib/IX complex. Phosphorylation consensus sequences are also located in the hinges or near them. Degeneracy within every even-numbered repeat between 16 and 24 and the insertion before repeat 24 may convert interactions within chains to interactions between chains to account for dimer formation within a domain of 7 kD at the carboxy-terminus. The structure of ABP dimers resembles a leaf spring. Interchain interactions hold the leaves firmly together at one end, whereas intrachain hydrophobic bonds reinforce the arms of the spring where the leaves diverge, making it sufficiently stiff to promote high-angle branching of actin filaments. The large size of the leaves, their interruption by two hinges and flexible actin-binding site, facilitate cross-linking of widely dispersed actin filaments.

Amino Acid Sequence↗
PubMed1989

Severe disability in rheumatoid arthritis: assessment following comprehensive rehabilitation.

26 patients with rheumatoid arthritis (RA) who presented with severe disability to a rheumatology unit were reviewed following comprehensive rehabilitation. This comprised in-patient evaluation, alteration in drug therapy, physical and occupational therapy and in many cases, orthopaedic surgery. Sustained benefit is observed 4-6 years later in terms of disease activity and functional class. The greatest improvement in functional class was noted in those patients who underwent joint replacement.

Adrenal Cortex Hormones↗