In addition to their g = 1.94 EPR signal, nitrogenase Fe-proteins from Azotobacter vinelandii, Azotobacter chroococcum and Klebsiella pneumoniae exhibit a weak EPR signal with g approximately equal to 5. Temperature dependence of the signal was consistent with an S = 3/2 system with negative zero-field splitting, D = -5 +/- 0.7 cm-1. The ms = +/- 3/2 ground state doublet gives rise to a transit...

The discovery of hydrogenase in Azotobacter cells (1) raises the question of its function in the metabolism of this organism. This enzyme is usually found in anaerobic or facultative anaerobic bacteria which liberate Hz from certain substrates. Azotobacter is a strict aerobe, and its metabolism consists primarily in the simple oxidation of substrate to carbon dioxide and water. Although not con...

Melanins, the ubiquitous hetero-polymer pigments found widely dispersed among various life forms, are usually dark brown/black in colour. Although melanins have variety of biological functions, including protection against ultraviolet radiation of sunlight and are used in medicine, cosmetics, extraction of melanin from the animal and plant kingdoms is not an easy task. Using complementary physi...

in order to investigate the effects of plant growth promoting rhizobacteria (pgpr) inoculation on the morphological traits of tarragon a factorial pot experiment, based on completely randomized design with four replications, were conducted in research field of horticulture department of mohaghegh ardabili university in 2010 - 2011. treatments consisted of inoculation with three species of rhizo...

The effect of NADH on the activity of the purified pyruvate dehydrogenase complexes (PDHc) of Enterococcus (Ec.) faecalis, Lactococcus lactis, Azotobacter vinelandii and Escherichia coli was determined in vitro. It was found that the PDHc of E. coli and L. lactis was active only at relatively low NADH/NAD ratios, whereas the PDHc of Ec. faecalis was inhibited only at high NADH/NAD ratios. The P...

The enzyme quinoprotein glucose dehydrogenase (GDH) catalyses the oxidation of glucose to gluconic acid by direct oxidation in the periplasmic space of several Gram-negative bacteria. Acidification of the external environment with the release of gluconic acid contributes to the solubilization of the inorganic phosphate by biofertilizer strains of the phosphate-solubilizing bacteria. Glucose deh...

It is well known that the medium upon which bacteria are grown has a definite influence on the properties of the resulting cells. Several investigators (l-3) have reported that the physiological activities of species of Azotobacter may be altered by t,he growth medium. This investigation was undertaken to determine the response of Axotobacter cells to different organic compounds available for r...