Immunoglobulin kappa-chain mRNA was hybridized with DNA in order to assess the kappa-gene frequency. Kappa-mRNA was purified from membrane-bound ribosomes of mouse myeloma MOPC-41 by poly (U) chromatography and isolation of a 13S RNA by successive sucrose density gradient centrifugations. The RNA coded for kappa-chain precursor molecules in cell-free protein synthesis and essentially no other p...

Our previous study (R.G. Nath and F-L. Chung; Proc. Natl. Acad. Sci. USA, 91: 7491-7495, 1994), using a 32P postlabeling method combined with high-performance liquid chromatography specifically developed for exocyclic adducts, has shown that acrolein- and crotonaldehyde-derived 1,N2-propanodeoxyguanosine adducts (AdG and CdG, respectively) are present in the liver DNA from humans and rodents wi...

Common carp is a fish species of economic importance in China;traditionally it mostly salt-fermented. In the fermenting process, bacterial community spontaneously fermented important for its flavour and quality. However, very few studies have been conducted about relationship between development involved salt-fermentation carp. Therefore, we explored this by determining components, including am...

Caulobacter crescentus RNA polymerase holoenzyme and core enzyme have been separated by chromatography on denatured DNA-cellulose and purified by phosphocellulose chromatography. In order to assess the functional role of the putative C. crescentus CT subunit, the enzymes were compared to Escherichia coli holoenzyme and core RNA polymerases, and the transcription of various DNA templates by C. c...

The covalent binding of the hepatocarcinogen aflatoxin B1 by rat liver microsomes to calf thymus DNA resulted in a binding level equal to one aflatoxin residue per 60 DNA nucleotides. An aflatoxin derivative-guanine adduct was efficiently liberated from DNA with formic acid. Analytical reversed-phase high-pressure liquid chromatography of the DNA hydrolysate revealed that approximately 90% of t...

Dibenzo[a,/]pyrene (DB[a,/]P), an environmental hydrocarbon and very potent carcinogen in rodent bioassays, could be activated to DNA-binding intermediates in cells through formation of three different regioisomeric bayor fjord-region diol-epoxides or other more highly oxidized metaboUtes. The mechanism of metabolic activation of DB[a,/]P in the human mammary carcinoma cell line MCF-7 was eluci...

Novobiocin-Sepharose was prepared by coupling of novobiocin to Epoxy-activated Sepharose 6B and used as an affinity adsorbent. Four novobiocin-binding proteins were isolated from crude extracts of Escherichia coli with molecular weights of 105, 92, 85 and 40 kdal. The two larger proteins were identified as the A subunit (gyrA protein) and the B subunit (gyrB protein) of DNA gyrase topoisomerase...