THE KINETICS OF BACTERIOLYSIS IN THE GUT OF THE DEPOSIT FEEDER ARENICOLA-MARINA

A turbidimetric technique was used to measure the bacteriolytic activi ties of digestive fluids collected seasonally from the deposit-feeding polychaete Arenicola marina. Lysis of cultured sedimentary bacteria w as monitored spectrophotometrically. The kinetics of the lytic reactio n were characterized with respect to temperature, pH, reactant concent ration, and time. Bacteriolysis generally followed saturation kinetics behavior and was apparently a first-order process with respect to the substrate (bacteria), Deviation from a simple Michaelis-Menten relati onship, however, was observed at high substrate levels, at which inhib ition of lysis was evident. The lytic rate decreased rapidly and sharp ly through time as the substrate was depleted. Lytic factors in the gu t fluid acted as catalysts; rates increased with concentration of gut fluid, but no depletion in lytic capacity through time,vas observed. T he lytic rate increased exponentially for all seasonal samples over th e range of environmental temperatures (4 to 31 degrees C) but showed l ittle relationship with pH under conditions likely to be experienced i n situ. The lytic rate also varied among bacterial strains and with cu lture age.