Dai Nippon Printing Co., Ltd Medi·Ca CC for Enumeration of Coliform Bacteria.

A ready-made dry medium method for coliform count, the Medi·Ca CC method, was compared to the Violet Red Bile Agar method (Bacteriological Analytical Manual, Chapter 4, Enumeration of Escherichia coli and the Coliform Bacteria, Section G) for nine raw foods from four food categories: raw ground pork, raw lamb, raw ground chicken, raw tuna fillet, raw salmon fillet, raw shrimp, fresh peeled banana, fresh cut pineapple, and fresh cut apple. The 95% confidence interval for the mean difference between the two methods at each contamination level for seven matrixes from all four categories fell within the range of -0.50 to 0.50, and no statistical difference was observed at all three contamination levels for four matrixes from three categories. These results demonstrated that the Medi·Ca CC method is a reasonable alternative to the reference method for raw meat, raw poultry, raw fish, and fresh fruits.

Dai nippon printing co., ltd, Medi-Ca AC for enumeration of aerobic bacteria. Performance tested method 041302.

A ready-made dry medium method for aerobic count, the MediCa AC method, was compared to the AOAC Official Method 966.23, Microbiological Methods, for seven different heat-processed meat matrixes: cooked roast beef, Chinese barbecued pork (barbecued pork seasoned with honey-based sauce), bacon, cooked ham, frankfurter (made from beef and pork), and boiled and cooked pork sausage. The 95% confidence interval for the mean difference between the two methods at each contamination level for each matrix fell within the range of -0.50 to 0.50, and no statistical difference was observed at all three contamination levels for five matrixes. These results demonstrate that the Medi-Ca AC method is a reasonable alternative to the AOAC 966.23 method for cooked meat products.

An automated multiplex specific IgE assay system using a photoimmobilized microarray.

An automated microarray diagnostic system for specific IgE using photoimmobilized allergen has been developed. Photoimmobilization is useful for preparing microarrays, where various types of biological components are covalently immobilized on a plate. Because the immobilization is based on a photo-induced radical cross-linking reaction, it does not require specific functional groups on the immobilized components. Here, an aqueous solution of a photoreactive poly(ethylene glycol)-based polymer was spin-coated on a plate, and an aqueous solution of each allergen was microspotted on the coated plate and allowed to dry in air. Finally, the plate was irradiated with an ultraviolet lamp for covalent immobilization. An automated machine using these plates was developed for the assay of antigen-specific IgE. Initially, the patient serum was added to the microarray plate, and after reaction of the microspotted allergen with IgE, the adsorbed IgE was detected by a peroxidase-conjugated anti-IgE-antibody. The chemical luminescence intensity of the substrate decomposed by the peroxidase was automatically detected using a sensitive charge-coupled device camera. All the allergens were immobilized stably using this method, which was used to screen for allergen-specific IgE. The results were comparable with those using conventional specific IgE. Using this system, six different allergen-specific IgE were assayed using 10 µL of serum within a period of 20 min.

Encouraging effect of cadherin-mediated cell-cell junctions on transfer printing of micropatterned vascular endothelial cells.

We made micropatterned vascular endothelial cells, which have a regular capillary tube-like structure, on a bioactive hydrogel matrix. We applied a stamping method to transfer micropatterned bovine aortic endothelial cells to a growth factor-reduced basement membrane matrix (Matrigel) and type I collagen gel. In this study, we addressed the issues of how to accelerate cell transfer and the effective factors in doing so. We focused on the effects of the cell-substratum and cell-cell adhesiveness prior to applying cultured endothelial cells to a hydrogel matrix on cellular behavior under transfer printing. We found that individual cells cultured sparsely on substrata with different cell adhesivity transferred to Matrigel up to 40%, whereas cells cultured on patterned substrata having lines of 60 mum in width, which involved cell-cell contacts, could transfer homogeneously to Matrigel within a few hours. The morphology of such cells changed from a tape-like monolayer into a thinner, tube-like structure. The speed and the ratio of transfer of micropatterned cells to Matrigel were affected by the period of cell culture on micropatterned substrata. We also found that the intensity of vascular endothelial cadherin staining at cell-cell junctions of micropatterned cells was correlated with cellular behavior when applying them to Matrigel, on which cells formed a tube-like structure or to which cells migrated individually. Furthermore, micropatterned cells made regular tube-like structures when applied to type I collagen gel. Such tube-like endothelial cells had good viability. These findings may be useful for creating in vitro angiogenesis assays and tissue-like constructs that include capillary-like networks of vascular endothelial cells.

Design of a serine protease-like catalytic triad on an antibody light chain displayed on the yeast cell surface.

Lc-WT, the wild-type light chain of antibody, and Lc-Triad, its double mutant with E1D and T27aS designing for the construction of catalytic triad within Asp1, Ser27a, and original His93 residues, were displayed on the cell surface of the protease-deficient yeast strain BJ2168. When each cell suspension was reacted with BODIPY FL casein and seven kinds of peptide-MCA substrates, respectively, a remarkable difference in hydrolytic activities toward Suc-GPLGP-MCA (succinyl-Gly-Pro-Leu-Gly-Pro-MCA), a substrate toward collagenase-like peptidase, was observed between the constructs: Lc-Triad-displaying cells showed higher catalytic activity than Lc-WT-displaying cells. The difference disappeared in the presence of the serine protease inhibitor diisopropylfluorophosphate, suggesting that the three amino acid residues, Ser27a, His93, and Asp1, functioned as a catalytic triad responsible for the proteolytic activity in a similar way to the anti-vasoactive intestinal peptide (VIP) antibody light chain. A serine protease-like catalytic triad (Ser, His, and Asp) is considered to be directly involved in the catalytic mechanism of the anti-VIP antibody light chain, which moderately catalyzes the hydrolysis of VIP. These results suggest the possibility of new approach for the creation of tailor-made proteases beyond limitations of the traditional immunization approach.