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.

To assess the immunological cross-reactivity of the monobactam antibiotic aztreonam (AZ), rabbits were immunized with protein conjugates of benzylpenicillin, cephalothin (CEPH), and AZ. The resulting antibenzylpenicilloyl (BPO) and anti-CEPH rabbit antibodies showed negligible cross-reactivity with AZ conjugated to human serum albumin (AZ-HSA), whereas anti-AZ showed negligible cross-reactivity...

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...

Hydroxylated cytokinin, 2-methylthio-N6-(4-hydroxy-3-methylbut-2-enyl) adenosine, was found in the tRNA of Azotobacter vinelandii. This cytokinin had the trans configuration, unlike the cis configuration reported for that from other bacteria. Culture-condition-dependent changes in the content of this thiocytokinin and a few other thionucleosides in the tRNA of this bacterium have been observed.

Rock colonization by plant roots and their associated microbiota is one of the major drivers of mineral weathering, nutrient cycling, soil formation and ecosystem stability. Yet the mechanisms of biouptake of lithogenic elements from rocks with differential nutrient availabilities and limitations are yet to be established. Here we present results from a mesocosm experiment that examined lithoge...

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 ...

The genetic diversity among 31 putative Azotobacter isolates obtained from agricultural and non-agricultural soils was assessed using rep-PCR genomic fingerprinting and identified to species level by ARDRA and partial 16S rRNA gene sequence analysis. High diversity was found among the isolates, identified as A. chroococcum, A. salinestris, and A. armeniacus. Selected isolates were characterized...