A new cell line and an antibody for determining the activity of botulinum toxin are disclosed. Also disclosed is a method of determining the activity of botulinum toxin using the cell line and/or the antibody.

The present invention provides a polypeptide comprising an N-terminal polypeptide domain having luciferase activity and a C-terminal polypeptide domain having VAMP1, VAMP2 or VAMP3 activity where VAMP stands for vesicle-associated membrane protein. Corresponding nucleic acid molecules, expression vectors and genetically modified cells are also provided. The invention also provides methods and uses of the same.

Compositions comprising optimized aptamers capable of specifically binding to a surface protein of Clostridium difficile spore are provided. A method for detecting, enriching, separating, and/or isolating Clostridium difficile spores is provided.

Systems, methods, and devices are described herein for identifying, monitoring, isolating, or selecting a cell having a predefined characteristic in a mixed population of cells utilizing a combination of any one or more of iDEP, a region of localized field enhancement, a variable frequency electric field, a wide bandwidth amplifier, and/or an imaging apparatus.

Methods for detecting and/or quantifying the potency of an agent using a cell-based assay are disclosed. A mammalian cell culture is grown upon a microelectrode array (MEA) which is used to measure an electrophysiological response of the mammalian cell culture. The cell culture is exposed to the agent, generally in at least two different dosages. The potency of the agent is detected by measuring a change in the electrophysiological responses associated with the at least two dosages when compared to a control condition. These changes can include the weighted mean firing rate (wMFR) and bursting of the cells.

Provided herein, inter alia, are methods for measuring and assessing intestinal health in poultry. The disclosed microbial biomarkers and associated methods for identifying and quantifying the same are reliable, rapid and, in some embodiments, non-invasive, and can be used to provide information with respect to the gut health of poultry, such as chickens.

Methods for increasing specific uptake of a Botulinum neurotoxin are provided. Specific neurotoxin uptake by cells capable of being intoxicated by Botulinum neurotoxin is enhanced by increasing temperature from about 37° C. to up to about 41° C., as indicated by a decrease in the EC.sub.50 found for cells so treated. The effect requires the presence of both heavy and light chains of the Botulinum neurotoxin, and is serotype selective.

The present specification discloses SNAP-25 compositions, methods of making α-SNAP-25 antibodies that bind an epitope comprising a carboxyl-terminus at the P.sub.1 residue from the BoNT/A cleavage site scissile bond from a SNAP-25 cleavage product, α-SNAP-25 antibodies that bind an epitope comprising a carboxyl-terminus at the P.sub.1 residue from the BoNT/A cleavage site scissile bond from a SNAP-25 cleavage product, methods of detecting BoNT/A activity, and methods of detecting neutralizing α-BoNT/A antibodies.

The present invention relates to a polypeptide comprising an epitope having a sequence homology of at least 75% to a sequence section of both Clostridium difficile toxin A and B. Moreover, the present invention refers to a vaccine comprising such polypeptide. The invention further relates to an antibody binding to Clostridium difficile toxins A and B and to a method for isolating and/or detecting such antibody and to uses of the polypeptides and antibodies.

Compositions for characterization of botulinum toxin (BoNT) are described that include a genetically modified cell that is transfected with an artificial construct comprising a nucleic acid sequence that encodes for a hybrid protein having (a) a reporter-containing portion chemically coupled to (b) a cleavage site and (c) a control fluorophore. The cleavage site interacts with a BoNT in a manner that cleaves the reporter-containing portion from remainder of the construct. The cleaved portion is destroyed or otherwise degraded by the local environment, and presence of BoNT is evidenced by reduction in signal from the reporter. The cleavage sequence is all or part of a SNARE protein, the cleavable reporter-containing portion is preferably Yellow Fluorescent Protein (YFP), Citrine, Venus, or a YPet protein and the control fluorophore is preferably CFP, mStrawberry, or a mCherry protein.