BACKGROUND L-tryptophan is used widespread in the pharmaceutical industry. The majority of L-Trp production depends on microbial processes that produce L-tryptophan from indole and L-serine. These processes are very costly due to the costs of precursors, especially L-serine. Use of inexpensive substitutions as the L-serine source of L-tryptophan production enables us to reach a cost-effective p...

The natural history of genital Chlamydia trachomatis infections can vary widely; infections can spontaneously resolve but can also last from months to years, potentially progressing to cause significant pathology. The host and bacterial factors underlying this wide variation are not completely understood, but emphasize the bacterium's capacity to evade/adapt to the genital immune response, and/...

It is now well recognized that the product of a series of biosynthetic reactions can play an important controlling role in its formation, either by inhibiting the activity or the formation of the enzymes concerned with its synthesis (Vogel, 1957; Pardee, 1959). Since the extent of such control is largely dependent on the intracellular concentration of the particular metabolite involved, the lev...

In Euglena gracilis the terminal four enzyme activities of the tryptophan biosynthetic pathway were found to be associated with a protein with an estimated molecular weight of 325,000 +/- 20,000. The protein was purified approximately 2,000-fold with relatively proportional recoveries of all four enzyme activities. The purified material was homogeneous by the criteria of analytical disc gel ele...

As members of the family of heme-dependent enzymes, the heme dioxygenases are differentiated by virtue of their ability to catalyze the oxidation of l-tryptophan to N-formylkynurenine, the first and rate-limiting step in tryptophan catabolism. In the past several years, there have been a number of important developments that have meant that established proposals for the reaction mechanism in th...

Since most archaea are extremophilic and difficult to cultivate, our current knowledge of their biology is confined largely to comparative genomics and biochemistry. Haloferax volcanii offers great promise as a model organism for archaeal genetics, but until now there has been a lack of a wide variety of selectable markers for this organism. We describe here isolation of H. volcanii leuB and tr...

abstract now, it’s completely proved that we can find strains among many strains of each rhizobial group that can also do effective process in plant growth promoting as plant growth hormones production (iaa), in addition of their ability in n2 fixation .therefore, the aim of this research is to determinate the ability of iaa production of some of the indigenous rhizobial strains by two quantita...

We have constructed a genomic library of Neurospora crassa DNA in a cosmid vector that contains the dominant selectable marker for benomyl resistance. The library is arranged to permit the rapid cloning of Neurospora genes by either sib-selection or colony-hybridization protocols. Detailed procedures for the uses of the library are described. By use of these procedures, a modest number of unrel...

Recently medium conditions have been developed which stimulate the formation of the indole alkaloid ajmalicine in cell suspension cultures of Catharanthus roseus [6]. When cells were subjected to these conditions the alkaloid accumulation was preceded by a 12-fold increase of the specific activity of tryptophan decarboxylase. The enzyme activity showed a maximum two days after the cell transfer...