PRISM :: Browsing by Author "Ceri, Howard"

Browsing by Author "Ceri, Howard"

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Open Access
A mucosal surface model of pseudomonas aeruginosa infections
(2012) Nelson, Lisa K.; Ceri, Howard; Turner, Raymond J.
In the human body, mucosal sites such as the lungs, eyes, gastrointestinal tract and urinary tract are often the target of bacterial infections. One of the most notorious bacterial species known to infect mucosal surfaces is the opportunistic pathogen Pseudomonas aeruginosa. As such, there has been much research devoted to studying the mechanisms by which P. aeruginosa infects these surfaces, particularly how it causes chronic infections as these infections are problematic and difficult to eradicate. However, because P. aeruginosa is an opportunistic pathogen - in that it typically causes infection of mucosa! sites when they are compromised by disease, injury, or implanted medical devices - it has proved difficult to model infections by these bacteria. Consequently, in this work, we hypothesized that we could develop a novel model using the rat prostate for studying acute and chronic P. aeruginosa infections at mucosal surfaces. Unlike current mammalian models of chronic infections, this model has an advantage: chronic infections can easily form at the prostate mucosal surface without foreign body assistance. Therefore, using this model, we were able to study how chronic P. aeruginosa infections were influenced by processes that occur within the biofilm - a mode of adherent bacterial growth that is resistant to clearance. We found that signalling via quorum sensing was required to maintain a chronic infection, but this was likely due to its role in biofilm function rather than formation. We also showed, for the first time, that generation of variants associated with biofilm growth occurred in vivo using similar genetic pathways previously identified in vitro. Furthermore, we ascertained that the generation of variants could be critical for maintaining an infection, and that a heterogeneous population of variants was produced during mucosal surface infections. Finally, we expanded on the utility of our model and showed that diversity via multi-isolate infections affected chronic P. aeruginosa virulence. Thus, altogether, using our novel prostate model we were able to determine that signalling and diversity generation were important for chronic P. aeruginosa infections at mucosa! surfaces. These findings should have important implications for the development of better therapeutics against P. aeruginosa.
Open Access
Bacterial virulence factors and prostatitis: roles of secreted autotranporter toxin (sat) from escherichia coli and zapa from proteum mirabilis
(2007) Phan, Van C.; Ceri, Howard
Open Access
Biofilm physiology and cyclic-di-gmp in escherichia coli
(2012) Stan, Michelle A.; Turner, Raymond J.; Ceri, Howard
Open Access
Biofilms of Gastrointestinal Microflora
(2010) Willoughby, Kimberley M.; Ceri, Howard
Open Access
Cell regulatory properties of an endogenous heparin binding lectin
(1989) Westra, Yolande N.; Ceri, Howard
Open Access
Characterisation of microbial communities degrading C5+ hydrocarbons
(2000) Kay, Jason G.; Ceri, Howard
Open Access
Drinking water microflora biofilms and chlorine susceptibility
(2012-07-19) Schwering, Monika C.; Ceri, Howard
Waterborne disease outbreaks are especially dangerous in immunocompromised individuals and can be caused by biofilm formation in water systems. The aim of this work was to collect a group of environmental isolates, including opportunistic pathogens, from treated water systems with the purpose of creating a model drinking water system biofilm. This model biofilm would be used to explore the resistance of biofilms to chlorine at levels typical of a water distribution system. Isolates for the model biofilm were collected from Calgary and Ontario, sequenced and then as single and multi-species biofilms exposed to chlorine. The resistance, biofilm structure and microbial community were examined. It was found that biofilm organisms are consistently more resistant than planktonic and that multi-species biofilms even more so. Little change was seen in biofilm communities after treatment. The 3D structure of the biofilm appeared to have a role in resistance by limiting diffusion and protecting inner cells.
Open Access
Formation of single and mixed species biofilms of pseudomonas aeruginosa and the burholderia cepacia complex
(2004) Tomlin, Kerry L.; Ceri, Howard
Open Access
Galectins in the prostate
(1996) Oke, Katherine E.; Ceri, Howard
Open Access
Growth and biocide susceptibility of environmental mixed species biofilms
(2003) Huddleston, William R.; Ceri, Howard
Open Access
Mucosal surfacemolecules of the urinary bladder
(1998) Howard, Sean Ryan; Ceri, Howard
Open Access
Multi-metal resistance and tolerance in pseudomonas fluorescens: contributions of metabolism, morpholigcal variation and the gac/rsm signal transduction system
(2010) Workentine, Matthew L.; Turner, Raymond J.; Ceri, Howard
Open Access
Multimetal resistance and tolerance in microbial biofilms
(2008) Harrison, Joe J.; Turner, Raymond J.; Ceri, Howard
Open Access
PCR/DNA analysis of archaeological faunal remains from Rocky Mountain House and Morleyville (1834-1861, 1875-1896), Alberta, Canada
(2004) Pelly, Lorine P.; Ceri, Howard
Two settlements in south central Alberta, Rocky Mountain House, a fur trade post, and Morleyville, a Methodist mission, were occupied contemporaneously and situated in close proximity in the same geographic region. Both settlements contained substantial quantities of fragmentary bone making it difficult to specifically identify the species of origin. Ancient DNA analysis was employed to determine the species of origin of a significant number of bones from both sites. It was believed that ancient DNA analysis would help clarify faunal utilization patterns at Rocky Mountain House and Morleyville. Primers were designed to amplify a 124 base pair fragment of the cytochrome b gene in ruminants. Elk, moose, bison, cow and caribou sequences were recovered from Rocky Mountain House, a fur trade post. Elk was most highly represented at approximately 65% of the sequences recovered. This contradicts the conventional wisdom that bison were the most common food source here. Cow, elk, bison, pig and mule deer sequences were recovered from Morleyville. Ancient DNA analysis allowed the separation of cow and bison remains at Morleyville, which previously had not been possible. Since unidentified bones at Rocky Mountain House were reasonably abundant, this presented an opportunity to examine predictors of DNA survival. It was expected that an association would exist between the ability to amplify DNA and the state of preservation of the bone. It was not possible to confirm this expectation.
Open Access
Protease-activated receptors in the prostate
(2005) Hirschfeld, Aaron F.; Ceri, Howard
Open Access
Proteinase-activated receptor 1 (par1) elicits immunomodulatory effects in a mouse model of nonbacterial prostatitis
(2012) Stanton, M. Mark; Buret, Andre G.; Ceri, Howard
The prostate is an accessory reproductive gland that is found in all male mammals. This gland is prone to infection, inflammation, and cancer, making it one of the most disease-prone tissues in the body. Specifically, the role of Proteinase-Activated Receptor 1 (PARl) has not been addressed in the context of nonbacterial prostatitis. In this study, P ARl and P AR2 were localized primarily to the apical prostatic epithelium in C57BL/6 mice. Instillation of the PARl agonist TFLLR-NH2 into the mouse prostate significantly diminished dinitrobenzene sulfonic acid (DNBS)-induced prostatitis. Furthermore, TFLLR-NH2 also elicited non-PARl-rnediated imrnunornodulatory effects that were protective against DNBS-induced prostatitis. TFLLR-NH2 directly up-regulated antiinflammatory IL-10 production and the source of this IL-10 elevation was not macrophage-driven. Overall, these findings support an immunomodulatory role for P ARI in the mouse prostate and may present a pharmacological therapy for nonbacterial prostatitis.
Open Access
Proteinase-Activated Receptor-1 and Immunomodulatory Effects of a PAR1-Activating Peptide in a Mouse Model of Prostatitis
(2013-12-29) Stanton, M. Mark; Nelson, Lisa K.; Benediktsson, Hallgrimur; Hollenberg, Morley D.; Buret, Andre G.; Ceri, Howard
Background. Nonbacterial prostatitis has no established etiology. We hypothesized that proteinase-activated receptor-1 (PAR1) can play a role in prostatitis. We therefore investigated the effects of PAR1 stimulation in the context of a new model of murine nonbacterial prostatitis. Methods. Using a hapten (ethanol-dinitrobenzene sulfonic acid- (DNBS-)) induced prostatitis model with both wild-type and PAR1-null mice, we examined (1) the location of PAR1 in the mouse prostate and (2) the impact of a PAR1-activating peptide (TFLLR-NH2: PAR1-TF) on ethanol-DNBS-induced inflammation. Results. Ethanol-DNBS-induced inflammation was maximal at 2 days. In the tissue, PAR1 was expressed predominantly along the apical acini of prostatic epithelium. Although PAR1-TF on its own did not cause inflammation, its coadministration with ethanol-DNBS reduced all indices of acute prostatitis. Further, PAR1-TF administration doubled the prostatic production of interleukin-10 (IL-10) compared with ethanol-DNBS treatment alone. This enhanced IL-10 was not observed in PAR1-null mice and was not caused by the reverse-sequence receptor-inactive peptide, RLLFT-NH2. Surprisingly, PAR1-TF, also diminished ethanol-DNBS-induced inflammation in PAR1-null mice. Conclusions. PAR1 is expressed in the mouse prostate and its activation by PAR1-TF elicits immunomodulatory effects during ethanol-DNBS-induced prostatitis. However, PAR1-TF also diminishes ethanol-DNBS-induced inflammation via a non-PAR1 mechanism by activating an as-yet unknown receptor.
Open Access
Purification, characterization and localization of an endogenous lectin from quail intestine
(1989) Fang, Rixun; Ceri, Howard
Soluble extracts of quail intestinal mucosa contain a lectin activity specific for chicken and rabbit, trypsinized?? glutaraldehyde-fixed erythrocytes. This lectin activity could be totally inhibited by lactose and mucin. Quail lectin was first purified by affinity chromatography on either asialofetuin-Sepharose or mucin-Sepharose, followed by DEAE-Sepharose chromatography. Silver stains of SOS-PAGE revealed a single 14.5 kDaprotein. Gel filtration on Sephadex G-200 also yielded an apparent molecular weight of 14.5 kDa. suggesting the lectin is in a monomeric form. Isoelectric focusing of purified quail gut lectin resulted in its separation into a major band at pl 6.2 and four trace bands at 6.25, 6.27, 6.38 and 6.45. Immunochemical localization of quail gut lectin in the intestine was carried out with polyclonal antibody raised in rabbits and tested for specificity on Western blots. Immunohistochemical staining showed that the lectin is present in the secretion coating the mucosal surface of the small bowel and in goblet cells. Lectin could be purified from all sections of intestine and localized to goblet cells in all cases.
Open Access
Spatial distributions of Pseudomonas fluorescens colony variants in mixed-culture biofilms
(BioMed Central, 2013-07-28) Workentine, Matthew L; Wang, Siyuan; Ceri, Howard; Turner, Raymond J
Open Access
Studies of the role(s) of galectin in quail intestinal mucin organization and secretion
(1994) Fang, Rixun; Ceri, Howard
A program of studies was undertaken to explore the role(s) played by galectins at the mucosal surface. The first phase of this project involved purification and characterization of intestinal galectins from rabbit, rat, and quail. A family of galectins were found in mammalian intestinal tissues, however, only a single galectin was identified from the quail. In the second stage of this project, quail intestinal mucin was purified and the biochemical and immunological properties were characterized. Quail mucin was purified by two sequential isopycnic density-gradient centrifugations in CsCl followed by gel filtration chromatography. Purified quail mucin was then characterized by SDS-PAGE, amino acid and carbohydrate composition analyses, immuno-cross reactivity with mammalian mucin antibodies and sensitivity to disulphide-reduction, H2O2 , and trypsin. Quail mucin was revealed to be high molecular weight polymer composed of large heterogeneous glycoprotein monomers and a 110 kD 'link' protein, held together by disulphide bonds. Quail mucin was further identified as a putative ligand for quail galectin in binding studies and through immunohistochemical co-localization in goblet cells. The quail galectin binds quail mucin through the B-galactose residues on the carbohydrate side chains of quail mucin as shown by hapten inhibition studies. A putative membrane receptor of quail galectin on the brush border membrane of the quail small intestine was also detected by radioactive ligand binding assays. The regulation of mucin secretion from the quail small intestine was investigated using in vitro organ culture. Mucin secretion was enhanced by cholera toxin and regulated in a similar fashion to mammalian mucin; being stimulated by cholinergic but not adrenergic stimuli and being sensitive to the activation of protein kinase C and changes in Ca2 + levels. Quail galectin seems to serve as an adhesion molecule for extracellular mucus gel adherence to the epithelial surfaces and maybe also serve as a control for mucin release, which is evidenced by the following discoveries: (1) lactose could release both quail galectin and quail mucin from intestinal tissue; (2) blocking of galectin binding to the mucosal surfaces with antiserum against quail galectin could induce quail mucin release; and (3) binding the mucosal receptors for quail galectin with plant lectins could specifically reduce the rate of baseline secretion of quail mucin. However, lactose-induced mucin release was independent of the muscarinic receptor, protein kinase C and Ca2 +, suggesting that quail galectin may control mucin release through a unique pathway.