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E Märtlbauer

Publications and source records attributed to E Märtlbauer.

35 records · Page 2Linked to original sources
PubMed1995

Use of monoclonal antibodies for the analysis of mycotoxins.

Hybridomas producing monoclonal antibodies against aflatoxin M1, ochratoxin A, zearalenone, T-2 toxin, diacetoxyscirpenol, 3-acetyl-deoxynivalenol, fusarenon X, and roridin A were developed after immunization of BALB/c mice and fusion of the splenocytes with myeloma cells. The antibodies were characterized in terms of immunoglobulin subclass, sensitivity, and specificity. The use of these antibodies in competitive enzyme immunoassays, either as microtiter plate assays or membrane-based quick tests, as well as for the production of immunoaffinity columns is described. The advantages and disadvantages of monoclonal antibodies compared to polyclonal antisera for the improvement of mycotoxin analysis are discussed.

Animals↗
PubMed1995

An indirect enzyme immunoassay for the mycotoxin citrinin.

An indirect competitive enzyme immunoassay using rabbit antisera could detect citrinin in buffer solutions at 1 to 13 ng/ml (0.05 to 0.65 ng per assay). Cross-reactivity with austdiol, alternariol, ochratoxin A, and deoxynivalenol was < 0.1% relative to citrinin. Recovery of citrinin added to wheat flour at 200 to 2,000 ng/g was 89 to 104%, with a coefficient of variation of 6.9 to 13%.

Animals↗
PubMed1994

Immunochemical detection of antibiotics and sulfonamides.

To control the maximum residue limits (MRLs) for residues of veterinary drugs in food of animal origin, according to EU regulations, a broad spectrum of sensitive analytical methods is required. One effective approach is the development of immunoassays, particularly for screening purposes. Strategies for the production of specific polyclonal and monoclonal antibodies against beta-lactams, tetracyclines, streptomycin, chloramphenicol, sulfonamides and trimethoprim, are outlined, as well as methods for the synthesis of the respective enzyme-labelled antigens. The sensitivity and the specificity of the antibodies were characterized, and the immunochemical test systems were designed as quantitative routine tests (microtitre plate format) and as rapid qualitative tests (membrane-based assay formats). The detection limits of the assays were found to be well below the regulatory limits. The range of recovery, for the analysis of artificially contaminated samples, was between 68 and 104%. In principle, the enzyme immunoassays for antimicrobial drugs showed the advantage of sensitivity and speed together with the simplicity of manipulations involved in the procedure. However, because of the results of the specificity studies, as well as the possibility of false positive results owing to unspecific inhibition of the assay, confirmation of immunoassay results is still required for all legal and statutory purposes.

Animals↗
PubMed1994

Enzyme immunoassay for the detection of isoxazolyl penicillin antibiotics in milk.

Polyclonal antibodies were raised against isoxazolyl penicillins in rabbits after immunization with a cloxacillin-human serum albumin conjugate. The antisera were tested in direct and indirect competitive enzyme immunoassays (EIAs), using glucose oxidase or horseradish peroxidase conjugates of oxacillin, cloxacillin, or dicloxacillin, respectively, as the labelled antigen. The relative cross-reactivities of each test system with oxacillin, cloxacillin, and dicloxacillin, determined from the amount of antibiotic required for 50% inhibition of labelled antigen binding, were dependent on the antibiotic used as the labelled antigen. Other beta-lactam antibiotics did not cross-react in these test systems. In a direct EIA using a cloxacillin-horseradish peroxidase conjugate, cloxacillin and dicloxacillin in milk were detected at levels of 10 and 30 ng ml-1; the average recoveries at these levels were 102 and 84%, respectively.

Animals↗
PubMed1992

Studies on the application of enzyme immunoassays for the Fusarium mycotoxins deoxynivalenol, 3-acetyldeoxynivalenol, and zearalenone.

Polyclonal antisera against zearalenone (ZEA) were produced in rabbits after immunization with ZEA-oxime coupled to human serum albumin. Using these antibodies and a ZEA-oxime-horseradish peroxidase conjugate in a competitive direct enzyme immunoassay (EIA), the detection limit for ZEA was 70 pg/ml. The relative cross-reactivities of the assay with ZEA, alpha-zearalenol, beta-zearalenol, zearalanone, alpha-zearalanol, and beta-zearalanol, respectively, were 100%, 37.3%, 7.2%, 59.2%, 5.3%, and 3.9%, respectively. This EIA and two EIAs for deoxynivalenol (DON) and 3-acetyldeoxynivalenol(3-AcDON) (Usleber et al., 1991) were used to analyze wheat samples. The limits of determination for DON, 3-AcDON, and ZEA in wheat were 200 ppb, 50 ppb, and 20 ppb, respectively. The analysis of reference materials (wheat flour) containing DON by EIA showed good agreement with the nominal values. The EIA for ZEA was in addition used to analyze biological fluids, obtained during a feeding trial. Two lactating cows were administered 25 mg and 100 mg ZEA per day, respectively, over a period of 6 days. Serum, milk, urine, and feces were assayed in the ZEA-EIA with and without sample treatment with beta-glucuronidase prior to the analysis. Maximum toxin levels (ZEA-equivalents) found in milk were 0.4 and 1.2 ppb (glucuronides). The toxin concentration in milk decreased rapidly after the last toxin administration. In the urine, maximum levels of toxin-glucuronide conjugates were 23 ppb and 24 ppb, respectively. The serum toxin levels corresponded to those found in milk. In the feces, mean values were 150 ppb and 500 ppb, respectively, no conjugated toxins were found in feces.

Animals↗
PubMed1991

[Detection of antibodies against the larva of Anisakis simplex in the pollock Pollachius virens using ELISA].

From the fact that older saithes (more than 5 years old) are showing significantly lower prevalence of attack by Anisakis larvae in lateral muscle than younger saithes (3-4 years old), the question arises if this phenomenon is based on a specific immune response. Therefore we have investigated serum samples from saithes of different ages by using an indirect ELISA to estimate the antibody-titer against excretory-secretory Anisakis antigen. Results showing a moderate correlation (r = 0.66) between the height of titer and the age of underfeeding saithes (post spawning) and a close correlation (r = 0.93) of saithes in an optimal condition (pre spawning). It may be concluded that the migration-distance and the lifetime of Anisakis larvae in lateral-muscle is influenced by a specific immune response which increases with the age of the saithes.

Age Factors↗
PubMed1989

A survey on the occurrence of Fusarium mycotoxins in Bavarian cereals from the 1987 harvest.

Bavarian cereals and wheat flour from the 1987 harvest were analysed for nivalenol (NIV) and deoxynivalenol (DON) using high performance liquid chromatography (HPLC) and for T-2 toxin and zearalenone (ZEA) by enzyme-linked-immunosorbent assay (ELISA). The study included 190 field samples of wheat, barley, rye and oat with visibly damaged ears, 45 samples of wheat intended for feed production and two series of wheat flour (type 550) and whole wheat flour collected in October 1987 and June 1988. The field samples examined showed a high DON contamination of wheat (87%) with an average of 3.96 mg/kg and a maximum of 43.8 mg/kg. Mean levels between 0.33 mg/kg and 0.27 mg/kg DON could be detected in barley, rye and oat. Of the wheat samples, 58% contained ZEA with a maximum of 1.560 mg/kg. The highest levels of ZEA were detected in samples which also showed high concentrations of DON. The NIV and T-2 toxin levels were comparatively low. Thirty percent of the samples showed NIV concentrations between 0.04 mg/kg and 0.29 mg/kg and 38% contained between 0.005 and 0.60 mg/kg of T-2. In the wheat samples for feed production, only DON was detected with an average of 0.190 mg/kg and a maximum of 0.75 mg/kg. The highest DON levels (0.58 mg/kg) from October 1987 were found in the wheat flour samples which were lower than the highest DON concentration (3.24 mg/kg) detected in the samples collected during June 1988. This fact was probably due to a substantial amount of non-contaminated wheat from 1986. The toxin concentrations in the whole wheat flour were not higher than in the type 550 flour.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1988

[Determination of ochratoxin A in human milk].

A method for the determination of ochratoxin A in milk is described. The milk is homogenized in a buffer solution at pH 1.6 to release ochratoxin A from its bond to proteins. Ochratoxin A is extracted with chloroform and the extract cleaned up using a base clean-up step. Analysis is performed by high-pressure liquid chromatography, using a reversed-phase column and fluorescence detection. The detection limit of the method is 0.1 ng/ml and the average recovery rate, tested in the range between 0.5 and 10.0 ng/ml, was found to be 83.1%. Chemical ionization mass spectrometry (direct exposure probe) and an enzyme immunoassay were used as confirmatory tests. Using this method, trace amounts of ochratoxin A were found in 4 of 36 randomly collected human milk samples.

Chromatography, High Pressure Liquid↗
PubMed1988

Development of a sensitive enzyme-linked immunosorbent assay for the detection of diacetoxyscirpenol.

An enzyme-linked immunosorbent assay (ELISA) for the detection of diacetoxyscirpenol (DAS) was developed. Antibodies against DAS were obtained after immunization of rabbits with DAS-hemiglutarate-human serum albumin (DAS-HG-HSA). After an immunization period of 6 weeks a sufficient level of specific antibodies was reached. A DAS-hemisuccinate-horseradish peroxidase-conjugate (DAS-HS-HRP) was prepared by an ester method and used as enzyme-labelled toxin in the competitive assay. The detection limit for DAS was about 10 pg/ml. The relative cross reactivity of the assay was 597.5, 5.2, 100.0, 2.5, and 1.5% for 3 alpha-acetyl-DAS, DAS, T-2 toxin, neosolaniol, and 15-acetoxyscirpenol, respectively.

Animals↗
PubMed1988

Enzyme immunoassay for the macrocyclic trichothecene roridin A: production, properties, and use of rabbit antibodies.

Antisera against roridin A were prepared by using a roridin A-hemisuccinate derivative coupled to human serum albumin as the immunogen. Antibodies could be detected in the sera of the immunized rabbits as early as 4 weeks after the initial exposure. After one booster injection at week 14, high antibody titers were measured over a period of 21 weeks. The specificity and sensitivity of the antibodies were tested by using roridin A-hemisuccinate coupled to horseradish peroxidase as an enzyme-linked toxin in a competitive assay with a double-antibody solid phase. The assay was most specific for the tested macrocyclic trichothecenes, and the relative cross-reactivities with roridin A, roridin J, verrucarin A, satratoxin H, and satratoxin G were 1, 0.41, 0.15, 0.15, and 0.07, respectively. When 16 nonmacrocyclic trichothecenes were tested, only diacetylverrucarol (0.0015) and verrucarol (0.0005) showed minor cross-reactivity. The sensitivity of the enzyme immunoassay for the detection of roridin A was in the range of 5 to 50 ng/ml (0.16 to 1.6 ng per assay).

Animals↗
PubMed1988

Production and characterization of monoclonal antibodies to the macrocyclic trichothecene roridin A.

Two murine monoclonal antibodies to the macrocyclic trichothecene roridin A are described. Screening for antibody production was performed on absorbed anti-mouse immunoglobulin serum as double-antibody solid phase, and further characterization was done on affinity-purified anti-mouse IgG serum. The antibodies, designated 5G11 and 4H10, had affinity constants for roridin A of 9.25 X 10(7) and 1.7 X 10(7) liters/mol, respectively. In monoclonal antibody-based direct enzyme immunoassays, these IgG1 antibodies had detection limits for roridin A of 0.4 ng/ml (0.02 ng per assay) and 1.8 ng/ml (0.09 ng per assay), respectively. Both antibodies were most specific for the tested macrocyclic trichothecenes. The relative cross-reactivities of antibody 5G11 with roridin A, roridin J, verrucarin A, satratoxin G, and satratoxin H were 100.0, 43.8, 16.7, 3.7, and 18.9%, respectively; for antibody 4H10 they were 100.0, 6.3, 64.0, 4.4, and 4.9%, respectively.

Animals↗
PubMedDate not supplied

Multimycotoxin dipstick enzyme immunoassay applied to wheat.

A membrane-based visual dipstick enzyme immunoassay for the simultaneous detection of up to five mycotoxins was developed. Multiple dots of the respective antibodies against aflatoxin B1 (AFB1), T-2 toxin (T-2), 3-acetyldeoxynivalenol (3-AcDON), roridin A (RA), and zearalenone (ZEA) were applied onto a dipstick membrane. The competitive immunoreactions were performed by incubation of the dipstick in a test tube containing sample solution and a mixture of the respective toxin-horseradish peroxidase conjugates. After a second incubation in enzyme substrate/chromogen solution, a complete suppression of the (blue) colour development of the respective dot was scored positive. Visual detection limits for AFB1, T-2, 3-AcDON, RA, and ZEA in buffer solution were 2 ng/ml, 5 ng/ml, 50 ng/ml, 30 ng/ml, and 5 ng/ml respectively. Using a simple extraction procedure, the detection limits of the multimycotoxin assay in artificially contaminated wheat samples were 30 ng/g, 100 ng/g, 600 ng/g, 500 ng/g, and 60 ng/g, respectively.

Food Contamination↗
PubMedDate not supplied

Comparison of enzyme immunoassay and mouse bioassay for determining paralytic shellfish poisoning toxins in shellfish.

Sixty shellfish samples (mussel [Mytilus edulis], queen scallops [Chlamys opercularis] and king scallops [Pecten maximus]), collected during routine surveillance for paralytic shellfish poisoning (PSP) toxins conducted by the UK Ministry of Agriculture, Fisheries and Food and the Scottish Office Agriculture, Environmental Fisheries Department, were analysed for contamination with PSP toxins by mouse bioassay (MBA), and by a competitive direct enzyme immunoassay (Ridascreen Saxitoxin ELISA). Using the MBA as the reference method (detection limit: 350 micrograms kg-1), no false negative results out of a total of 45 MBA-positive samples and one false positive result out of a total of 15 MBA-negative samples were obtained by ELISA. The correlation coefficient for MBA-positive samples (n = 45) was 0.78. At the regulatory level for PSP toxins (800 micrograms kg-1), 39 of the samples were correctly determined by ELISA to be above or below this level, toxicity was overestimated in two samples, and underestimated in four samples.

Animals↗
PubMedDate not supplied

Rapid determination of citrinin in corn by fluorescence liquid chromatography and enzyme immunoassay.

A rapid assay procedure was developed for mycotoxin citrinin in corn using liquid-liquid extraction (LLE) cartridges. Ground corn was extracted with methylene chloride and 0.5 N phosphoric acid. The extract was added to an LLE cartridge containing a diatomaceous-earth adsorbant, previously impregnated with sodium bicarbonate solution. After aspiration to dryness, the cartridge was eluted with methanol-water (4 + 1), and aliquots were taken for quantitation by reversed-phase liquid chromatography with fluorescence detection. Recoveries of citrinin added to ground corn at 200-1600 ng/g ranged from 71.2 to 86.3%, with coefficients of variation between 4.1 and 10.6%. An indirect enzyme immunoassay was also evaluated, using sodium carbonate solution for extraction. Recoveries of citrinin added to ground corn at 200-2000 ng/g ranged from 53.2 to 67.2%, but the coefficients of variation varied between 18.4 and 51.5%. The LLE cartridge procedure offers the advantages of low solvent consumption and speed, and is amenable to automation.

Adsorption↗
PubMedDate not supplied

Immunoassay methods for paralytic shellfish poisoning toxins.

The current status of immunochemical techniques for analysis of paralytic shellfish poisoning (PSP) toxins is summarized. Important aspects regarding production of the biological reagents necessary for immunochemical methods, the characteristics of polyclonal and monoclonal antibodies against saxitoxin and neosaxitoxin, and the importance of test sensitivity and specificity are discussed. Applications of immunochemical techniques for PSP toxins include microtiter plate enzyme immunoasays and enzyme-linked immunofiltration assays for toxin detection, and immunoaffinity chromatography (IAC) for sample extract cleanup. A major advantage of enzyme immunoassay (EIA) is simplicity and rapidity of the test procedure, and higher sensitivity than other methods. However, quantitative agreement between EIA and mouse bioassay is dependent on antibody specificity and the toxin profile in the shellfish; thus, both over- and underestimation of total toxicity may occur. For screening purposes, however, EIAs offer major advantages over the mouse bioassay, which is criticized in Europe because of animal welfare. A major application of antibodies against PSP toxins is their use for extract cleanup by IAC, which gives highly purified extracts, thereby enhancing determination of PSP toxins by conventional physicochemical methods such as liquid chromatography. IAC can also be used to isolate PSP toxins for preparation of analytical standard solutions.

Animals↗
PubMedDate not supplied

[Demonstration of zearalenone metabolites in bile of breeding sows with fertility disturbances].

Bile of 52 gilts with reproductive problems have been analyzed for zearalenone and alpha-zearalenol. The applied methods, HPLC in combination with a fluorescence detector and with ELISA, were suitable for survey of biological materials with a complex matrix such as bile. The detection limit and recovery rate were 1 ng/ml and 75%, respectively. Zearalenone and alpha-zearalenol, which were present as glucuronide conjugates, were detected up to 40.0 ng/ml and 66.1 ng/ml in all samples analyzed. This suggests that zearalenone occurs more frequently in feed for pigs than it was recognized by feed analysis. Further investigation have to show, if the detection of zearalenone and alpha-zearalenol in samples of bile indicates a participation of these mycotoxins in reproductive problems.

Animals↗