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C Turcotte

Publications and source records attributed to C Turcotte.

18 recordsLinked to original sources
PubMed2001

Production and characterization of anti-nisin Z monoclonal antibodies: suitability for distinguishing active from inactive forms through a competitive enzyme immunoassay.

As a pre-requisite to monoclonal antibody development, an efficient purification strategy was devised that yielded 72 mg of nisin Z from 14.5 1 of Lactococcus lactis subsp. lactis biovar. diacetylactis UL 719 (L. diacetylactis UL719) culture in supplemented whey permeate. Specific monoclonal antibodies (mAbs) were produced in mice against the purified nisin Z using keyhole limpet hemocyanin as a carrier protein. These antibodies did not recognize nisin A, suggesting that the asparagine residue at position 27 is involved in antibody recognition to nisin Z. However, the high reactivity of mAbs against biologically inactive nisin Z degradation products, produced during storage of freeze-dried pure nisin Z at -70 degrees C, indicated that the dehydroalanine residue at position 5 (Dha5), required for biological activity, is not necessary in nisin Z recognition by the mAb. A competitive enzyme immunoassay (cEIA) using the specific anti-nisin Z mAb was developed and used for rapid and sensitive detection and quantification of nisin Z in fresh culture supernatant, milk and whey. Detection limits of 78 ng/ml in phosphate-buffered saline, 87 ng/ml in culture supernatant, 106 ng/ml in milk and 90.5 ng/ml in whey were obtained for this assay. The cEIA using specific mAbs can be used to quantify nisin Z in food products.

Antibodies, Monoclonal↗
PubMed2001

Similar efficacy following four weeks treatment of asthmatics with formoterol 12 micrograms b.d. delivered by two different dry powder inhalers: differences in inhaler handling.

This randomised, multicentre, parallel-group study compared the clinical efficacy and ease of handling of two dry powder inhalers delivering the long-acting beta 2-agonist formoterol. After run-in, 200 asthmatics on treatment with inhaled corticosteroids and still presenting with suboptimal asthma control were randomised to receive 12 micrograms formoterol twice daily via either the Aerolizer inhaler (Foradil Aerolizer) or the Turbuhaler inhaler (Oxis Turbuhaler) for four weeks. Study variables included the mean morning pre-medication peak expiratory flow (PEF) during the last seven days of treatment and the correct inhaler handling according to inhaler-specific checklists. The mean difference in the effect on morning pre-medication PEF was 13.86 l/min in favour of formoterol via the Aerolizer inhaler (90% confidence interval 2.50, 25.21) in the intent-to-treat population. Eighty-six per cent of the patients under treatment with formoterol via the Turbuhaler inhaler performed correctly all the essential inhalation manoeuvres, whereas 98% of those on the Aerolizer inhaler did so. These results strongly suggest similar clinical efficacy with twice daily treatment of formoterol 12 micrograms metered dose delivered either by the Aerolizer, or the Turbuhaler device. They also suggest that handling the Aerolizer is easier than that of the Turbuhaler.

Administration, Inhalation↗
PubMed2000

Simultaneous immunofluorescent detection of coentrapped cells in gel beads.

An immunofluorescent method involving double color labeling and confocal microscopy was reported to specifically detect lactic acid bacteria and probiotic cells coimmobilized in gels beads. The method described is rapid (4 h) and sensitive and may be useful for studying cell dynamics during mixed-culture starter production using immobilized cells in gel beads. Microscopic observations were perfectly correlated to cell counts obtained using a sandwich enzyme-linked immunosorbent assay.

Bifidobacterium↗
PubMed1999

Production and characterization of polyclonal antibodies against cholecalciferol (vitamin D3).

Vitamin D is one of the essential vitamins in the human diet for normal growth and function. In Canada and the USA, fortified milk and milk products are the essential source of vitamin D. The adult recommended nutrient intake of vitamin D is 200 to 400 I.U. (corresponding to 5 to 10 microg) per day. Additional amounts of vitamin D do not confer benefits and may even be toxic. However, a deficiency of this vitamin leads to inadequate absorption of calcium and phosphorus and faulty mineralization of bones and teeth. Actual methods for measuring vitamin D in milk are limited in terms of sensitivity, rapidity and simplicity. The objective of this manuscript was to develop a new molecular strategy for the production, purification and characterization of polyclonal antibodies to vitamin D. Specific antibodies were raised in rabbits against vitamin D using cationized bovine serum albumin (cBSA) as a carrier protein. Anti-vitamin D antibodies were recovered from rabbit sera by sequential affinity chromatographies through Protein A/G Agarose, cBSA Sepharose and cOVA-vitamin D Sepharose columns. Although the yields of anti-vitamin D were relatively low, recovered antibodies showed high specificity and affinity to vitamin D. The purified antibody was used to develop a solid-phase enzyme immunoassay in order to determine the exact concentration of vitamin D in phosphate buffer. Using this immunoassay, approximately 35 ng of vitamin D can be detected within 3 h. The signal obtained was proportional to the amount of vitamin D in the sample analyzed. The strategy developed in this paper appears to be very promising in terms of sensitivity, rapidity and simplicity. It offers a great potential for automation and use on a routine basis for the quantification of vitamin D in fortified milk and other milk products.

Animals↗
PubMed1996

Studies into the role of the SEF14 fimbrial antigen in the pathogenesis of Salmonella enteritidis.

To investigate the role of the SEF14 fimbrial antigen in pathogenesis, a single defined sefA (SEF14-) inactivated mutant of Salmonella enteritidis strain LA5 was constructed and tested in a number of biological assay systems. There was no significant difference between the wild-type strain and the isogenic SEF14- mutant in their abilities to adhere to and invade HEp-2 epithelial cells or their survival in mouse peritoneal macrophages, whereas the SEF14- mutant was ingested more rapidly by isolated human PMN. Both the strains colonized the intestine, invaded and spread systemically in 1 day-old chicks, laying hens and BALB/c mice equally well. A significantly greater number of chicks excreted the wild-type SEF14+ strain during the first week following infection as compared to those infected with the SEF14- mutant. However, similar numbers of chicks excreted the two strains between 2 and 7 weeks after infection. These results indicate that possession of SEF14 fimbriae alone do not appear to play a significant role in the pathogenesis of S. enteritidis although its contribution to virulence may be dependent on the host species infected.

Animals↗
PubMed1995

Mutants of Escherichia coli heat-labile toxin lacking ADP-ribosyltransferase activity act as nontoxic, mucosal adjuvants.

A nontoxic mutant (LTK7) of the Escherichia coli heat-labile enterotoxin (LT) lacking ADP-ribosylating activity but retaining holotoxin formation was constructed. By using site-directed mutagenesis, the arginine at position 7 of the A subunit was replaced with lysine. This molecule, which was nontoxic in several assays, was able to bind to eukaryotic cells and acted as a mucosal adjuvant for co-administered proteins; BALB/c mice immunized intranasally with LTK7 and ovalbumin developed high levels of serum and local antibodies to ovalbumin and toxin. In addition, mice immunized intranasally with fragment C of tetanus toxin and LTK7 were protected against lethal challenge with tetanus toxin. Thus nontoxic mutants of heat-labile toxin can act as effective intranasal mucosal adjuvants.

Adjuvants, Immunologic↗
PubMed1993

Cloning, DNA nucleotide sequence and distribution of the gene encoding the SEF14 fimbrial antigen of Salmonella enteritidis.

Monoclonal antibody 69/25, specific for the Salmonella enteritidis fimbrial antigen (SEF14), was used to screen a pUC-based S. enteritidis gene library and a positive clone was identified. Subcloning experiments demonstrated that a 584 bp DraI DNA fragment was the minimal chromosomal segment capable of directing SEF14 antigen expression. Western blotting of Escherichia coli recombinants identified a gene product of M(r) 16000 as a precursor to the M(r) 14300 mature fimbrial subunit protein. The DNA nucleotide sequence of the DraI fragment was determined and was shown to contain a single open reading frame with two potential f-Met start codons and a hydrophobic signal sequence. Downstream of a putative peptidase cleavage site, the deduced amino acid sequence showed considerable homology with the N-terminal amino acid sequence of what was originally described as the type 1 fimbrial subunit of Salmonella enteritidis and later redefined as SEF14. The gene encoding SEF14, designated as sefA, was shown to be limited in distribution to Salmonella blegdam, S. dublin, S. enteritidis, S. gallinarum, S. moscow, S. pullorum, S. rostock, S. seremban and S. typhi, all belonging to Salmonella group D. However, expression of the SEF14 antigen was limited to S. dublin, S. enteritidis, S. moscow and S. blegdam. The nucleotide sequence of the sefA gene shared no homology with the Salmonella fimA gene encoding type 1 fimbriae, and these genes showed distinct patterns of distribution within salmonellae.

Amino Acid Sequence↗
PubMed1991

Chromatographic purification and characterization of antigens A and D from Mycobacterium paratuberculosis and their use in enzyme-linked immunosorbent assays for diagnosis of paratuberculosis in sheep.

The protein antigens A and D were purified from culture filtrates and sonic extracts of laboratory strains of Mycobacterium paratuberculosis by salt precipitation and chromatography. The characterization of antigen A is shown here, and both antigens were evaluated along with lipoarabinomannan antigen in indirect enzyme-linked immunosorbent assays (ELISA) for the serodiagnosis of ovine paratuberculosis. After anion-exchange (DEAE-5PW) and hydrophobic (phenyl-5PW) chromatography using high-performance liquid chromatography, antigen A showed a prominant band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) at 31 kDa with small amounts of low-molecular-mass proteins but with no evidence of antigen D. A single precipitin arc was evident with purified antigen A in crossed immunoelectrophoresis. The determination of the N-terminal amino acid sequence showed a high degree of homology between the 31-kDa component of antigen A and antigens of the BCG85 complex of Mycobacterium bovis BCG, a total of 24 of 26 residues being identical to those of BCG85C. A prominant SDS-PAGE band at 400 kDa and a single crossed-immunoelectrophoresis arc was also evident for antigen D after gel filtration (Sephacryl S-200), anion-exchange (DEAE-Sephacel), and concanavalin A-Sepharose affinity chromatography. By ELISA, purified antigen A detected antibody in the sera of 18 of 22 paratuberculosis-infected sheep (82% sensitivity), whereas the purified antigen D detected antibody in all 22 infected animals (100% sensitivity). Combined ELISA results showed increased specificity with some loss in sensitivity.

Amino Acid Sequence↗
PubMed1991

An evaluation of selected screening tests for bovine paratuberculosis.

The objective of this study was to evaluate the performance of the lipoarabinomannan antigen enzyme-linked immunosorbent assay (LAM-ELISA), carbohydrate antigen complement fixation (CH-CFT), and protein D antigen agar gel immunodiffusion (D-AGID) tests for bovine paratuberculosis, relative to histopathology, and to culture and isolation of Mycobacterium paratuberculosis from tissues and feces. Samples for test evaluation were collected from four sources including blood and tissues from 400 cull cows at three abattoirs in Ontario, blood and feces from a paratuberculosis survey of cattle from 120 dairy farms in Ontario, a serum bank containing samples from cattle from Ontario and Québec, and a bank of sera from cattle from Pennsylvania and the northeastern United States. The data were analyzed using receiver operator characteristic curves, estimates of relative sensitivity and specificity, and kappa statistics of agreement between tests. The LAM-ELISA performed significantly better than both the CH-CFT and the D-AGID tests. The LAM-ELISA was better at predicting fecal shedding status than tissue infection. However, the LAM-ELISA also had limitations. When interpreted as positive or negative (+/-), at a critical optical density of 0.675, its sensitivity and specificity relative to bacteriology were 49% and 87% respectively. Although the serological tests examined in this study provided some information, they did not predict well the infection status of individual animals.

Animals↗
PubMed1990

Protein G-based enzyme-linked immunosorbent assay for anti-MPB70 antibodies in bovine tuberculosis.

MPB70 is a highly species specific protein which is secreted from Mycobacterium bovis during culture. To investigate whether antibodies against MPB70 can be used as an indicator of infection with M. bovis, an enzyme-linked immunosorbent assay was developed, based on the use of biotinylated protein G, to provide a common indicator for antibody formation in different species. During experimental infection with M. bovis in cattle, a characteristic pattern of anti-MPB70 antibody production was observed with an initial flat plateau followed by a marked rise 18 to 20 weeks after infection. Skin testing with bovine tuberculin purified protein derivative (PPD), which was shown to contain antibody-reactive MPB70, was a potent stimulator of antibody production in infected animals. In experimentally infected cattle, we observed an inverse relationship between antibody activity and delayed-type hypersensitivity skin test reactions. In natural M. bovis infections, skin testing with PPD was also a potent stimulator of anti-MPB70 formation. Comparison between the enzyme-linked immunosorbent assay for antibodies to MPB70 and that for antibodies to the widely cross-reacting M. bovis BCG antigen 85B in animals with M. bovis, Mycobacterium avium, Mycobacterium paratuberculosis, and Corynebacterium pseudotuberculosis infections showed that formation of antibody to MPB70 was highly specific for infection with M. bovis. The use of an MPB70-containing PPD preparation for skin testing followed by this anti-MPB70 assay is a highly specific indicator of M. bovis infection. Adjustment of the test conditions is expected to provide an increased sensitivity of the procedure for the diagnosis of natural M. bovis infections.

Animals↗
PubMed1989

Serodiagnosis of ovine paratuberculosis, using lipoarabinomannan in an enzyme-linked immunosorbent assay.

The use of lipoarabinomannan (LAM; obtained from Mycobacterium paratuberculosis) in and ELISA (LAM-ELISA) to test 75 sheep sera from a paratuberculosis-infected flock resulted in an approximate threefold increase in sensitivity (from 23.5% to 70.6%), compared with the use of Annau's polysaccharide in a complement fixation test (P-CFT). Even after manipulation of the LAM-ELISA cut-off value to produce a specificity of 100% to match that of the P-CFT, the sensitivity still was approximately twofold greater than that of the P-CFT. Anti-bovine monoclonal antiglobulin-enzyme conjugates matched commercially available anti-ovine polyclonal antiglobulin-enzyme conjugates with respect to sensitivity and specificity. False-positive results were found to be less frequent after combining 2 serodiagnostic tests, LAM-ELISA and D antigenagar gel immunodiffusion, resulting in an increase in specificity from 88.1% to 95.2%. The repeatability of true seropositive and seronegative results was found to be 89.5% and 91.1%, respectively, for sera obtained less than or equal to 1 month prior to slaughter and 91.7% and 95.5%, respectively, for reanalysis of sera obtained at the time of slaughter.

Animals↗
PubMed1988

Evaluation of the serological response of sheep in one flock to Mycobacterium paratuberculosis by crossed immunoelectrophoresis.

Sera from 74 sheep culled from one flock on the basis of performance and response to immunological tests for paratuberculosis or maedi visna were used to evaluate the serological response to a sonicated antigen of Mycobacterium paratuberculosis by crossed immunoelectrophoresis. A total of seven precipitating components was demonstrated. Four components (A,C,V,W) were detected in low frequency only with sera from animals with paratuberculosis while two components (X,Y) were detected in high frequency with sera from animals with or without paratuberculosis. One component (D) was observed in high frequency with sera from animals with paratuberculosis. The magnitude of the serological response to the D component as measured by crossed immunoelectrophoresis correlated well with bacterial load and generally agreed with the quantitative assessment by agar gel immunodiffusion. A development time for crossed immunoelectrophoresis of 24-72 hours after electrophoresis was required to achieve correlation with agar gel immunodiffusion.

Animals↗
PubMed1982

FeCl3/HCl/KI versatile wide application reagent.

The multiplicity of the interaction products of FeCl3 and KI are adequate to detect drugs bearing a nitrogen group, bases, imides, purines, in particular. To take advantage of the chemical ability of the two constituents of the reagent singularly they are applied to the plate in sequence. FeCl3 will act as a positive ion Fe+3 and it will chealate, oxidate, and produce salts. KI by reacting with FeCl3 will produce a new chemical specie, for example, Fe(Cl3I3)6(-3), Werner complexes, and production of elemental iodine that further interacts with KI and drugs facilitating detection with adequate sensitivity and for practical use.

Chemical Phenomena↗
PubMed1982

Barbiturate chemistry: separation TLC identification and mechanism of reaction.

Thin layer chromatography and chemical detection procedures for barbiturates are described and the reaction mechanism introduced. We show that by this technique barbiturates can be characterized as long, intermediate, short, and very short acting, with a few exceptions, by Rf value and by the typical spot color hue. The factors involved and chemical requirements for color are mentioned, e.g. 1. Behavior in organic solvents 2. Silica Gel polarity and pH 3. Functional groups responsible for interaction with the reagent 4. pH and chemicals of the color developer 5. Mechanism of reaction.

Barbiturates↗
PubMed1981

[Presence of the bacterial kidney disease in salmonid fish in Quebec (author's transl)].

Presence of the bacterial kidney disease in salmonid fish in Quebec During the summers of 1979 and 1980, wild and hatchery fish were analysed for the presence of the bacterial kidney disease (BKD) agent in salmonid fish in Quebec by the indirect immunofluorescence technique. The causative agent of BKD was detected in all hatcheries tested. Ten to 25% of the fish were positive. The presence of this agent was independent of age and species. We were unable to detect the BKD in fish from the rivers in the northern part of Quebec (over the 50th parallel). The first detection of BKD in Quebec was made in the spring of 1979 in a hatchery. A high mortality occurred in fish over a year old. The majority of the fish were positive by immunofluorescence and the bacteriun was isolated from some fish. Three weeks before the disease appeared, six ponds received fish from this hatchery. No mortality was observed in those ponds and in the middle of the summer the percentage of carrier fish by immunofluorescence was approximately 20%.

Animals↗