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Biomedical subjects

R Brzezinski

Publications and source records attributed to R Brzezinski.

27 records · Page 2Linked to original sources
PubMed1992

A versatile shuttle cosmid vector for use in Escherichia coli and actinomycetes.

A shuttle cosmid vector has been constructed for Escherichia coli and actinomycetes. This vector, pFD666, utilizes the origin of replication (ori) of the broad-host-range plasmid, pJV1, from Streptomyces phaeochromogenes, for replication in actinomycetes and is compatible with vectors derived from pIJ101. The pFD666 vector employs the neomycin phosphotransferase-encoding gene (neo) from transposon Tn5 as the selective marker. To achieve this, the native promoter of neo was replaced by one optimized for expression in both hosts. The polylinker used for cloning has nine unique sites flanked by the promoters for T7 and SP6 RNA polymerase for the production of specific RNA probes. Terminators on both sides of the polylinker protect the vector from transcription originating from cloned inserts. An M13 ori allows the production of single-stranded DNA.

Actinomycetales↗
PubMed1991

An improved aminoglycoside resistance gene cassette for use in gram-negative bacteria and Streptomyces.

A cloning cassette, carrying a modified amino-glycoside resistance gene (neo) from transposon Tn5 was constructed. Three restriction sites internal to the neo gene were eliminated by in vitro mutagenesis, allowing their use in designing new cloning vectors. The original, suboptimal transcription promoter was replaced with a synthetic sequence corresponding to the consensus for E. coli and Streptomyces promoters. The cassette has numerous restriction sites for easy subcloning of the promoter, the coding sequence or the whole gene.

Amino Acid Sequence↗
PubMed1989

Expression of a mouse metallothionein gene in transgenic plant tissues.

Three gene constructions based on a mouse metallothionein I gene (mMT-I) were introduced into tobacco using a Ri plasmid vector system to test the effectiveness of animal gene regulatory signals in plant cells. No transcription from the native mouse gene was observed. In plant cells bearing chimeric mMT-I genes in which transcription was driven by the nopaline synthase promoter, neither polyadenylation nor splicing of mMT-I pre-mRNA was observed. Detailed comparisons of mMT-I sequences with those of known plant genes were carried out; slight differences in regions of known consensus sequences may be at least partly responsible for the non-recognition of mMT-I gene regulatory signals in plant cells, though other as yet unidentified, potentially necessary sequences may also be involved.

Animals↗
PubMed1988

Characterization of SE-3, a virulent bacteriophage of Saccharopolyspora erythraea.

SE-3 is a virulent bacteriophage isolated from a large-scale culture of Saccharopolyspora erythraea, an erythromycin producer. The host range of the phage is narrow, limited to some strains of this species. Another strain of Sac. erythraea, and a strain of Sac. hirsuta, are able to adsorb phage particles but do not sustain their complete multiplication. SE-3 is closely related to the phage SE-5 as shown by DNA restriction mapping. The differences between SE-3 and SE-5 genomes are apparently limited to two DNA segments flanked by short inverted repeats, visualized by electron microscopy.

Bacteriophages↗
PubMed1987

Cloning and characterization of the metallothionein-I gene from mouse LMTK cells.

A clone of about 14 kb containing the metallothionein MT-I gene and three repetitive sequences, was isolated from a genomic library of mouse LMTK DNA. The MT-I gene was functional. Transfected cells became cadmium resistant. Two of the three repetitive sequences were moderately repetitive while the other was closely related to the R family.

Animals↗
PubMed1986

Characterization of alcohol dehydrogenase in young soybean seedlings.

Molecular properties of alcohol dehydrogenase (ADH) were examined in young soybean seedlings. Soybean radicle tissue is ADH-rich. Enzyme specific activity decreases slowly with the development of roots and becomes almost undetectable when the first true leaves appear. Soybean ADH was not found to be inducible by flooding. 2,4-Dichlorophenoxyacetic acid (2,4-D) treatment increased ADH specific activity as much as 14-fold. Only one ADH isozyme was detected by isoelectric focusing. By DNA-DNA hydridization, soybean ADH genomic sequences were shown to be partly homologous to maize ADH1 cDNA. The presence of more than one Adh gene in soybean is discussed.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1986

Restriction mapping and close relationship of the DNA of Streptomyces erythraeus phages 121 and SE-5.

The biological properties and genome structure of two actinophages, 121 and SE-5, infecting Streptomyces erythraeus were characterized. They had the same host range (limited to S. erythraeus) and similar DNA G + C contents (around 60 mol %). Restriction maps of their genomes also showed many similarities. The close relationship between the two phages was confirmed by DNA hybridization experiments: large parts of their genomes were homologous, except for a segment in the middle of the map, where no hybridization was detected.

Bacteriophages↗
PubMed1983

Differential expression of cloned mouse metallothionein sequences in Escherichia coli.

A cDNA for mouse hepatic metallothionein I has been cloned into pBR322 (Mbikay et al., 1981). Although this recombinant plasmid (M135) possesses the metallothionein sequence in the same reading frame as that of beta-lactamase, it fails to direct the synthesis of a fused beta-lactamase-metallothionein protein in Escherichia coli. Another plasmid (M244) was derived from M135 by deleting an internal 390-bp segment made of the 5' noncoding region of metallothionein, the dG-dC tail, and some beta-lactamase sequences. Bacteria harboring the new plasmid now contain in their periplasmic space a cysteine-rich, cadmium-binding protein of 12,000 daltons, as expected. These observations demonstrate that expression of cloned DNA in bacteria could depend as much on its primary structure as on proper insertion in relation to a promoter.

Animals↗