The nature of enzyme inhibitions in bacterial luminescence: Sulfanilamide, urethane, temperature and pressure

Abstract

SEVEN FIGURESAccording to evidence recently obtained with luminous bacteria, a thermodynamic equilibrium between catalytically active and inactive forms of certain enzymes appears to exist normally within the living cell. This equilibrium has temperature and entropy characteristics resembling a protein denaturation. It is apparently a determining factor with regard to the optimum temperature for luminescence in a given species. I n addition, it is sensitive to hydrostatic pressure and apparently also to certain narcotics. The quantitative data and theoretical considerations which support this hypothesis have been discussed at sonie length in previous papers (Johnson, Brown and Marsland, '42, a, b ; Brown, Johnson and Marsland, '42; Eyring and Magee, '42; Johnson and Chase, '42).The purpose of the present study has been to extend the data and theory concerning the temperature relations of bacterial luminescence intensity in order to elucidate further the significance of the phenomena observed in both normal and inhibitor-containing cell suspensions. Particular reference has been made to the action of sulfanilamide, whose inhibition of luminescenee may be reversed to a large extent by increase in temperature. The action of urethane also has been investigated further, since its inhibition is partially or wholly reversible with increase in hydrostatic pressure. In this effect, the urethane inhibition of luminescence resembles that due to heat alone, which is also reversible, in part, by pressure. The action of all these inhibitory agents is related to the optimum temperature of luminescence in the specific organism concerned. The results of the present study make it possible to evaluate of it given process, and to designate more precisely the action of added more clearly biological differences in the velocity-temperature re1 a t' lolls 1 These studies have been aided, in part, by n graut to one of us (3'. H. J.) from the Penrose Fund of the American Philosophical Society.

Modelling Net Photosynthetic Rate of Temperate Dry Grassland Species and Winter Wheat at Elevated Air Co2 Concentration

“…[6], where c is a scaling constant, ∆H a is an activation energy, R is the gas constant (R = 0.00831 kJ K -1 mol -1 ), T k is leaf temperature [K]. τ is a declining function of temperature whose activation energy is negative.…”

Drought impact on carbon and water cycling in a Mediterranean <i>Quercus suber</i> L. woodland during the extreme drought event in 2012

“…Medlyn et al (2002) and Kattge and Knorr (2007) described the temperature dependency of both, the maximum carboxylation rate V c,max of the Ru- bisco enzyme and the maximum electron transport rate J max by a peaked function, according to Johnson et al (1942) (Eq. A7).…”

Understanding the impact of plant competition on the coupling between vegetation and the atmosphere

“…nitrogen [Anten et al, 1995;Harley et al, 1992], temperature [Johnson et al, 1942;Farquhar et al, 1980], CO 2 and soil and atmospheric water content [Tuzet et al, 2003]. In this model the gross photosynthesis rate of a leaf (P gl ) is the minimum of the carboxylation or Rubisco limited photosynthesis rate (P cl ) and the electron transport limited photosynthesis rate (P jl ) [Farquhar et al, 1980].…”