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Research has been conducted on the versatile conditional-replication, integration and modular plasmids. Results indicate that these plasmids can be replicated at medium and high copy numbers in different hosts for creating gene or mutant libraries.

Novel methods were used for constructing tightly regulated rhamnose promoter and arabinose fusions in researches involving Escherichia coli phosphate regulon. The approaches involved uncoupling phoR and phoB expression from the normal controls by putting them behind the rhamnose-controlled PrhaB or foreign, arabinose-controlled ParaB promoter. The results showed that the the strains exhibited almost normal Pi control of the Pho regulon after induction of the corresponding delta-phoR and delta-phoB mutant containing either rhamnose or arabinose.

A study of the regulation fo the Enterococcus faecium BM4147 vancomycin resistance gene cluster by the VanS-VanR two-component regulatory system in Escherichia coli was conducted. The research made use of appropriate strains for examining the in vivo activation of VanR by VanS, acetyl phosphate, nonpartner sensor kinase PhoR and mutant forms of VanS. Results indicated that the phospho-VanR is a transcriptional activator. Furthermore, VanS acts as a P-VanR phosphatase.

Research reveals that a new enzymatic pathway involving three enzymes including ribose 1,5-bisphosphokinase, encoded by phnN gene, is required for the synthesis of 5-phospho-D-ribosyl alpha-1-diphosphate (PRPP). Furthermore, phnN gene product ribose 1,5-bisphosphokinase catalyzes phosphonae degradation. NAD biosynthesis requires PRPP in Escherichia coli.