The research work was conducted to isolate and characterize salinity tolerant Azotobacter sp. to be use as biofertilizer. In this study, soil samples were collected from different salinity affected areas, namely Pankhali Bazar of Dakop Upazilla, Khulna, Bangladesh and Dargapur Village, Assasuni Upazilla, Satkhira, Bangladesh. Thirtyfive colonies were isolated from pore-plate containing Ashby's ...

Temperature affects the expression of the three different nitrogenases in Azotobacter vinelandii. Molybdenum repressed the vnfH and anfH operons relatively more at 30 degrees C than at 20 degrees C; at 14 degrees C molybdenum did not repress these genes at all. Similarly, V repressed the anf operon at 30 degrees C but not at 20 or 14 degrees C. Mo was poorly transported into cells grown at the ...

Pleomorphism in cultures of Azotobacter vinelandii was induced by addition of Difco peptone to the growth medium. Under the conditions of the study, 5% peptone gave rise to transient forms described as "fungoid cells" which were osmotically fragile. After some 48 hr of culture, they became osmotically stable and resumed a more typical morphology. It was shown that the pleomorphism-inducing prin...

The site or sites that protect nitrogenase from O(2) inactivation in vivo are sensitive to sodium azide or 2,4-dinitrophenol. Both components of nitrogenase can be synthesized when oxidative phosphorylation is disrupted.

nitrogen and phosphorus are two necessary macronutrients for plant growth and yield. these two elements now will be added to soil by chemical fertilizers. this research has been carried out based on randomized completely block design with three replications at markazi provience agricultural research station, iran, during growing season of 2004-2005 to evaluate the effects of azotobacter chrooco...

A study was made of the food web formed from a protozoon, two bacteria, and a glucose minimal medium in chemostat culture. The system was also divided into simpler parts, first by omitting the protozoon to obtain a competition system, and then by omitting one or the other of the bacteria to obtain two food chains. In the competition studies, one bacterium was displaced by the other at all holdi...

An account has been given elsewhere of the successful isolation of physiological x-ray mutants of Azotobacter agilis with genetic blocks in the substrate oxidation mechanisms (1). The present paper deals in greater detail with a mutant strain, designated A13, that was isolated as a variant unable to grow on glucose, and gives the methods used to characterize the particular deficiency responsibl...

Interconversion between [4Fe-4S] cubane and [3Fe-4S] cuboidal states represents one of the simplest structural changes an iron-sulphur cluster can undertake. This reaction is implicated in oxidative damage and in modulation of the activity and regulation of certain enzymes, and it is therefore important to understand the factors governing cluster stability and the processes that activate cluste...

Recent studies have provided several types of evidence supporting the view that ammonia is the key intermediate in nitrogen fixation by Azotobacter. An alternative hypothesis based on hydroxylamine depends almost entirely on the detection of traces of oximes in cultures fixing nitrogen. Although the two hypotheses are not mutually exclusive (Burris and Wilson, 1945), hydroxylamine remains an im...

Area around the root zone i.e. rhizosphere is a rich environment for plant growth promoting bacteria (PGPR) which can be utilized in many way to improve the growth of crop and yield. In agriculture one of the limiting factors is providing plant nutrition particularly nitrogen and phosphorus to the crop. Different Plant-Growth Promoting Rhizobacteria (PGPR) such as Azospirillum, Azotobacter, Bac...