Biomedical subjects

R S Graham

Publications and source records attributed to R S Graham.

5 recordsLinked to original sources

PubMed1990

Efficiency of transcriptional terminators in Bacillus subtilis.

To promote more efficient synthesis of heterologous gene products in a Bacillus subtilis host, we have developed a system for rapidly testing the effect of a putative terminator on in vivo gene expression. Terminator structures from the Bacillus amyloliquefaciens amyE gene, the Bacillus licheniformis penP gene, the B. subtilis bglS gene, and the Bacillus thuringiensis cry gene were subcloned and inserted into a vector in such a way as to disrupt expression of the cat-86 gene. Comparisons are made between gene expression levels and the stabilities of the respective stem-loop structures.

Bacillus subtilis↗

PubMed1990

A second molecular form of D2 dopamine receptor in rat and bovine caudate nucleus.

Overexpression of the D2 dopamine receptor has been proposed to be part of the pathology of schizophrenia. The isolation of a D2 dopamine receptor clone has assisted the molecular characterization of D2 receptor. We have now isolated an identical rat clone along with two other clones--a second related rat clone (RD-2in) and a homologous bovine clone (BD-2in), both of which contain an insert encoding an additional 29 amino acids relative to the original rat clone (RD-2o). All three clones encode D2 receptor binding sites when expressed in COS-7 cells. The amino-acid insert encoded by D-2in lies in the domain of the receptor believed to interact with the GTP-binding proteins (G proteins) of various signal transduction pathways. By using oligonucleotide probes specific for either D-2o or D-2in RNA transcripts, we have found that the level of expression of the D-2in-encoded form of the receptor is seven times that of the D-2o form in the caudate nucleus, the richest brain source of D2 receptors.

Amino Acid Sequence↗

PubMed1989

Electrodermal lability and visual information processing.

Individual differences in electrodermal lability have been related to performance in vigilance and reaction time tasks. The goal of the present study was to employ an "additive factors" approach to identify the stages of information processing that might underlie these effects. Nineteen labile and 17 stabile subjects performed a choice reaction time task in which a visual imperative stimulus was presented under two conditions of intensity (presumed to affect the speed of pre-processing operations) X three conditions of degradation (which influences later encoding processes related to feature extraction). Measures of both reaction time and movement time were obtained. The major findings were: (a) labile subjects had faster reaction times than stabiles, and (b) lability interacted significantly with stimulus degradation. Labiles also tended (p less than .10) to have faster movement times. This pattern indicates that labiles and stabiles differ in the performance of later encoding operations, and possibly in the speed of motor processes as well. However, they do not appear to differ in the early pre-processing of the simple physical attributes of a stimulus.

Adult↗

PubMed1977

Effect of site-specific endonuclease digestion on the thyP3 gene of bacteriophage phi 3T and the thyP11 gene of bacteriophage rho11.

phi 3T and rho11 are closely related bacteriophages of Bacillus subtilis which can "convent" thymine auxotrophs to thymine prototrophs upon infection or transfection. The effect of endonuclease digestion on the ability of both bacteriophage and prophage DNA from phi eT and rho11 to transform for thymine prototrophy was determined. All of the endonucleases tested: BamHI, Bg/II, BsuRI, EcoRI, HindII+ III, and HpaII reduced the efficiency of thyP transformation to an equal extent in prophage and bacteriophage DNA. Only HpaII completely abolished thyP transformation. The reduction in transformation with BamHI, Bg/II, BsuRI, EcoRI, and HpaII fragments is size related. The thyP transforming fragments generated by these endonucleases are potentially clonable.

Bacillus subtilis↗

PubMed1975

Antibiotic-resistant mutants of Bacillus subtilis conditional for sporulation.

Among spontaneously occurring antibiotic-resistant mutants of Bacillus subtilis 168 we have identified a sub-class that is conditionally sporulative. Mutants in this sub-class are resistant to antibiotic during vegetative growth but are sensitive during sporulation. Mutants conditionally-resistant to erythromycin, kanamycin, spectinomycin, and streptomycin have been isolated and characterized by phase contrast microscopy and with respect to their ability to synthesize heat-resistant endospores or the sporulation-associated enzyme alkaline phosphatase. The results suggest that several entirely different genetic lesions may result in this single phenotype. This group includes mutants whose properties suggest that both th 30S and 50S ribosomal subunits may be altered concomitant with early spore specific metabolism. The blockage imposed by antibiotic may be at or near Stage 2 of sporulation.

Anti-Bacterial Agents↗