Lactate Dehydrogenase Activity in Certain Strains of Staphylococcus aureus

Abstract

Lactate dehydrogenase (LDH) was studied in phage-propagating strains 29, 3A, 6, 81, and 42D of Staphylococcus aureus selected from the five groups in the International-Blair series. Cells were cultivated in Brain Heart Infusion (Difco) under nearly anaerobic conditions and were harvested near the end of the log phase. LDH activity-was maximal at the end of the exponential growth period and was measured spectrophotometrically by reduction of p-nitro-blue tetrazolium, with phenazine methosulfate as a coupling agent. Crude enzyme extracts were prepared both by an acetone extraction technique and by sonic treatment. LDH activity for these enzyme preparations was determined by the colorimetric method mentioned and also by measuring the rate of nicotinamide adenine dinucleotide reduction at 340 m,. The order of activity observed, by use of both assay methods, was 29 > 81 > 6 > 3A > 42D. LDH forms (possibly isoenzymes) for each of 15 strains, which represent the five phage-propagating groups of the International-Blair series, were separated by acrylamide gel electrophoresis. Five forms were distinguished and arbitrarily numbered on the basis of their rate of migration, no. 5 being the slowest component. No one strain had more than four, nor fewer than two, LDH forms. Form 3 appeared in 13 of the 15 strains and was followed in frequency by no. 2, 1, 4, and 5.

ASSESSMENT OF ANTIBACTERIAL ACTIVITIES OF PEDIOCIN PRODUCED BY PEDIOCOCCUS ACIDILACTICI LAB 5

“…Lactate dehydrogenase (LDH) is a cytoplasmic enzyme and its activity is routinely used to measure the cellular integrity. The nicotinamide adenine dinucleotide (NAD)-linked LDH (E.C.1.1.1.27) activity is measured following the decrease in absorption at 340 nm resulting from the pyruvate dependent oxidation of NADH following the method of Stockland and San Clemente (1968) with little modification. The rate of reduced NADH oxidation was measured in 3 mL cuvettes at 37C and 340 nm after 5 min incubation (UV-Vis 1700 Spectrophotometer, Shimadzu, Kyoto, Japan).…”

The Vesicular Acetylcholine Transporter Is Present in Melanocytes and Keratinocytes in the Human Epidermis

“…The remaining pellet was resuspended in lysis buffer and the supernatant provided the nuclear fraction. In order to ensure nuclear purity, samples were tested for cross-contamination via the lactate dehydrogenase assay (Stockland and San Clemente, 1968).…”

ROS mediated antibacterial activity of photoilluminated riboflavin: A photodynamic mechanism against nosocomial infections

“…The LDH activity was measured by evaluating the reduction of NAD + to NADH and H + as lactate is oxidized to pyruvate [25]. The treated bacterial cell suspension was centrifuged at 4 °C for 30 min at 300 g and pellet was collected in a microplate.…”