ABSTRACT
A sandwich ELISA technique was examined to detect Escherichia coli O157:H7 using chicken anti-E. coli O157:H7 IgY as the capture-antibody and an anti-E. coli O157 mouse mAb conjugated with biotin as the detection antibody. The anti-E. coli O157:H7 IgY was harvested from eggs laid by hens (23 weeks of age, Single Comb White Leghorn) immunized with formalin-killed E. coli O157:H7. The IgY was purified by water dilution methods and gel chromatography on Sephacryl S-300 followed by ammonium sulfate precipitation. The sensitivity (CFU/ml) of sandwich ELISA for the E. coli O157:H7 was repeatedly examined with 10 replicates of each sample and a standard curve was plotted. The sandwich ELISA can detect as low as 40CFU/ml of E. coli O157:H7. The data suggest that chicken IgY-based sandwich ELISA provides a reliable, inexpensive and sensitive assay for the detection of the food-borne pathogen E. coli O157:H7.
Subject(s)
Antibodies, Bacterial/chemistry , Escherichia coli O157/chemistry , Food Microbiology , Immunoglobulins/chemistry , Animals , Antibodies, Bacterial/immunology , Bacterial Typing Techniques/methods , Chickens/immunology , Chickens/microbiology , Enzyme-Linked Immunosorbent Assay/methods , Escherichia coli O157/immunology , Immunoglobulins/immunology , Sensitivity and SpecificityABSTRACT
The porcine infrapatellar fat pad is a structure composed of adipocytes and adipose connective tissues. Limited information is available concerning its chemical composition. Samples of the fat pad collected from young hogs were dissected into two portions: a relatively hard core of the pad with cushioning properties (inner tissue), and a soft adipose tissue surrounding the core (outer tissue). The inner tissue contained less moisture and nitrogen than did the outer tissue. The yield of dry-delipidated tissue was also lower in the inner tissue, indicating a higher content of lipid in this tissue. Fatty acid analysis showed that the proportions of C18: 1, C16: 1 and C18: 2n-6 are higher, and the proportion of C16: 0 is lower in the inner than in the outer tissue. Collagen is the major protein, with relatively small amounts of glycosaminoglycans in both tissues. The content of hyaluronic acid relative to sulphated galactosaminoglycan was lower in the inner than in the outer tissue. The electrophoresis pattern of sulphated galactosaminoglycan was also different between the two tissues. These results suggest that chemical composition varies between adipose tissues with different biomechanical function.
