Related Experiment Video
Updated: Jan 28, 2026

IridiumIII Luminescent Probe for Detection of the Malarial Protein Biomarker Histidine Rich Protein-II
Published on: July 7, 2015
Production of Histidine Decarboxylase and Histamine by Proteus morganii
R R Eitenmiller1, J W Wallis1, J H Orr1
1Department of Food Science, University of Georgia, Athens, Georgia 30602.
Abstract:
Examination of 22 Proteus morganii strains revealed that each possessed histidine decarboxylase activity. Strain GRMO 6 produced maximal activity (nanomoles of CO2 released/mg cells/h) when grown at ambient temperature (24 C) and at acid pH levels that tended to inhibit growth. Minimal activity was present when the culture was grown at pH 8.5. Histidine decarboxylase activity decreased as the age of the culture increased. Maximal reaction rates occurred at 37 C and pH 6.5. Rapid enzyme and histamine formation occurred in tuna fillets inoculated with P. morganii and stored at 24 and 30 C. Histamine levels reached 520 mg/100 g and 608 mg/100 g at 24 and 30 C, respectively. Little enzyme was produced in the inoculated fillets stored at 15 C and in the uninoculated control fillets.
Related Concept Videos
Acid Suppressive Drugs for Peptic Ulcer Disease: Histamine H2-Receptor Antagonists
Scalar Product (Dot Product)
The scalar product of two vectors is obtained by multiplying...
Vector Product (Cross Product)
Consider the cross product of two vectors. Imagine rotating the first vector about...
Wood Products
Glue-laminated wood, often referred to as glulam, combines multiple smaller pieces of dimensional lumber using adhesives to form a single, larger piece. Cross-laminated timber consists...
Dot Product
In engineering, the dot product of any two vectors is the product of the magnitudes of the vectors and the cosine of the angle between them. It is denoted by a dot symbol between the two vectors.
Consider a vehicle pulling an object along the ground using a rope. If the rope makes an angle with the horizontal axis, the work done can be calculated using the dot product of the force applied and the object's displacement.
The dot...
Cross Product
The magnitude of the cross product is obtained by multiplying the magnitude of both the vectors and the sine of the angle between them. This means that a larger angle between the vectors will lead to a greater magnitude of the cross product.

