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Newark, DE, United States

Tags are widely used to monitor a protein's expression level, interactions, protein trafficking, and localization. Membrane proteins are often tagged in their extracellular domains to allow discrimination between protein in the plasma membrane from that in internal pools. Multipass membrane proteins offer special challenges for inserting a tag since the extracellular regions are often composed of small loops and thus inserting an epitope tag risks perturbing the structure, function, or location of the membrane protein. We have developed a novel tagging system called snorkel where a transmembrane domain followed by a tag is appended to the cytoplasmic C-terminus of the membrane protein. In this way the tag is displayed extracellularly, but structurally separate from the membrane protein. We have tested the snorkel tag system on a diverse panel of membrane proteins including GPCRs and ion channels and demonstrated that it reliably allows for monitoring of the surface expression.


Clotilde L.M.,Magarray, Inc. | Salvador A.,California State University, East Bay | Salvador A.,U.S. Department of Agriculture | Bernard C.,U.S. Department of Agriculture | And 5 more authors.
Foodborne Pathogens and Disease | Year: 2015

Traditionally, serotyping of Escherichia coli has been performed via slide agglutination methods using antisera. More recently, multiplex immunoassays and "molecular serotyping" via polymerase chain reaction (PCR) have been validated for this purpose. In this study, the serogroups of 161 Shiga toxin-producing Escherichia coli (STEC) strains isolated from fecal samples of California cattle were typed by conventional methods using antisera as well as two newly developed multiplex PCR- and antibody-based microbead assays using the Luminex technology. Using the Luminex assays, we were capable of serotyping 11 STEC isolates that were previously determined untypeable for the O antigen by conventional methods using antisera. Except for 14 isolates, results from the 2 Luminex assays agreed. Copyright 2015, Mary Ann Liebert, Inc.


Pfleiderer G.,University of Basel | Battegay M.,University of Basel | Lindpaintner K.,SDIX
Knowing One's Medical Fate in Advance: Challenges for Diagnosis and Treatment, Philosophy, Ethics and Religion | Year: 2012

Modern medicine is now in a position to make advanced prognoses that chart the entire course of illness and recovery. Paradoxically, this is coupled with a new dimension of uncertainty for the patient, i.e. coming to terms with discovering they have an increased risk of a particular disease and deciding what appropriate steps to take. In this publication, renowned experts in their fields discuss these issues. The certainty and uncertainty of one's fate are discussed from both methodological and epidemiological perspectives, using examples of diseases for which treatment and prognosis have dramatically changed. Despite profound insights into the human genome, personalized genetically tailored medicine still lies in the future. Religious, spiritual and philosophical dimensions are discussed, as are the ways in which they may help people cope with these new insights into their future, e.g. the promise of an afterlife. This publication aims to bridge the different fields dealing with this area by addressing the challenges faced and encouraging dialogue. It will be of interest to all readers who deal with ethical problems of prognosis, particularly in medicine, as well as to theologians and sociologists. © 2012 by S. Karger AG, Basel. All rights reserved.


Muldoon M.T.,SDIX | Allen A.-C.O.,SDIX | Gonzalez V.,SDIX | Sutzko M.,SDIX | And 4 more authors.
Journal of AOAC International | Year: 2012

The SDIX RapidChekTM Listeria F.A.S.T. test system was validated against the U.S. Department of Agriculture-Food Safety and Inspection Service (USDA-FSIS) cultural reference method for the detection of Listeria species on stainless steel, plastic, rubber, and painted concrete. The SDIX method uses a proprietary RapidChek Listeria enrichment media for a one-step, 24-40 h enrichment at 30°C, and detects Listeria on an immunochromatographic lateral flow device in 10 min. Different Listeria species were used to spike each of the environmental surfaces. Environmental surfaces were spiked at levels ranging from 50 to 400 cfu /surface (1 in.2 swabs for painted concrete, 4 in.2 for sponge). A total of 120 spiked samples were tested by the SDIX method at 24 and 40 h and the cultural reference method. Total confirmed positives were 49, 54, and 48 for the SDIX 24 h method, the SDIX 40 h method, and the USDA-FSIS cultural reference method, respectively. Nonspiked samples from all environmental surfaces were reported as negative for Listeria spp. by all methods. The overall Chi square was 0.017 (P = 0.104) and 0.611 (P = 0.566) after a 24 and 40 h enrichment, respectively, indicating that the test method was equivalent in performance to the reference method at both enrichment times. The SDIX method was evaluated for the detection of 50 Listeria and 35 non-Listeria bacterial strains. All 50 Listeria strains were detected by the method (100% sensitivity). Five out of 35 non-Listeria species gave light test signals when grown in nonselective broth culture and tested undiluted. However, when grown in the RapidChek Listeria F.A.S.T. proprietary media, only one bacterial strain (Staphylococcus aureus) was detected, giving a very low test signal (97% specificity). The method was shown to be robust toward several alterations in testing and storage conditions. © 2012 Publishing Technology.


Muldoon M.T.,SDIX | Gonzalez V.,SDIX | Sutzko M.I.,SDIX | Allen A.-C.O.,SDIX | And 6 more authors.
Journal of AOAC International | Year: 2011

The RapidChek SELECTTM Salmonella Enteritidis Test System was validated for the detection of Salmonella Enteritidis (SE) in poultry house drag swabs, shell egg pools, and chicken carcass rinsates. The method utilizes RapidChek SELECTTM Salmonella (AOAC PTM License No. 080601) proprietary primary and secondary enrichment media. Following enrichment, an immunochromatographic test strip is inserted into the tube containing the secondary enrichment broth, developed for 10 min, and interpreted. Salmonella Enteritidis-inoculated samples (1-5 CFU SE/analytical unit) were tested by the test method as well as the appropriate cultural reference method U.S. Food and Drug Administration-Bacteriological Analytical Manual (drag swabs and egg pools) or U.S. Department of Agriculture-Food Safety and Inspection Service (chicken carcass rinsates). A total of 80 samples were tested by both methods in the study. Fifty-two samples were positive by the RapidChek SELECT Salmonella Enteritidis method and 38 were found positive by the respective reference method. The sensitivity of the method was 100% and the specificity was 100%. The accuracy of the test method was 137%, indicating that the method was more sensitive than the reference method. The RapidChek SELECT Salmonella Enteritidis method was tested with 82 Salmonella Group D1 strains including 63 Salmonella Enteritidis strains as well as 32 non-Salmonella Group D1 strains representing 10 bacteria genera. The test method detected all 82 Group D1 strains (100% sensitivity). None of the non-Salmonella Group D1 or other genera of bacteria were detected, indicating a specificity of 100%. The method was shown to be highly robust and stable under control and accelerated stability conditions. © 2012 Publishing Technology.

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