3 articles published in JoVE
A Purification and In Vitro Activity Assay for a (p)ppGpp Synthetase from Clostridium difficile Astha Pokhrel1, Asia Poudel1, Erin B. Purcell1 1Department of Chemistry and Biochemistry, Old Dominion University Here, we describe a method for purifying histidine-tagged pyrophosphokinase enzymes and utilizing thin layer chromatography of radiolabelled substrates and products to assay for the enzymatic activity in vitro. The enzyme activity assay is broadly applicable to any kinase, nucleotide cyclase, or phosphor-transfer reaction whose mechanism includes nucleotide triphosphate hydrolysis.
Stiffness Measurement of Soft Silicone Substrates for Mechanobiology Studies Using a Widefield Fluorescence Microscope Yashar Bashirzadeh*1, Siddharth Chatterji*1, Dakota Palmer*2, Sandeep Dumbali*1, Shizhi Qian1, Venkat Maruthamuthu1 1Department of Mechanical & Aerospace Engineering, Old Dominion University, 2Department of Biological Sciences, Old Dominion University Substrates with stiffness in the kilopascal-range are useful to study the response of cells to physiologically relevant micro-environment stiffness. Using just a widefield fluorescence microscope, the Young's modulus of soft silicone gels can be determined using an indentation with a suitable sphere.
Experimental Assessment of Mouse Sociability Using an Automated Image Processing Approach Frency Varghese1, Jessica A. Burket2, Andrew D. Benson2, Stephen I. Deutsch2, Christian W. Zemlin1 1Department of Electrical and Computer Engineering and Frank Reidy Center for Bioelectrics, Old Dominion University, 2Department of Psychiatry & Behavioral Sciences, Eastern Virginia Medical School This protocol describes a method to quantify mouse sociability. Mice are videotaped as they move and interact in a special cage. Movie processing allows for the automated quantification of sociability with excellent accuracy and reliability.