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Biomedical subjects

J Garwood

Publications and source records attributed to J Garwood.

13 recordsLinked to original sources

A novel cytoplasmic hemimethylated oriC binding activity.

Using hemimethylated, fully methylated, and unmethylated oligonucleotide probes corresponding to part of the origin of Escherichia coli DNA replication, oriC (+81-136), we have characterized a novel hemimethylated DNA-specific protein binding activity. This activity appears to be located in the cytoplasm rather than in membrane fractions. It has been partially purified and, in DNase footprinting analysis, found to preferentially protect only a subset of the hemimethylated GATC sites present in the minimal oriC. These sites are found adjacent to the DnaA binding box, R1, and overlap the integration host factor binding site. The activity does not correspond to known hemimethylated binding proteins, although in the seqA deletion mutant, there is a 3-fold reduction of the activity. The stage of the cell cycle in synchronized PC2 cultures does not seem to significantly affect thte relative levels of this binding activity. A possible role in sequestration of the newly replicated hemimethylated origin is discussed.

Bacterial Outer Membrane Proteins

Co-ordination between membrane oriC sequestration factors and a chromosome partitioning protein, TolC (MukA).

oriC DNA in the hemimethylated (but not in the fully methylated) state reacts with an Escherichia coli K-12 outer membrane preparation. This reaction is drastically reduced when the membrane preparation of a seqA null mutant is used. An in vitro reconstitution of the activity was undertaken by adding a partially purified SeqA protein to a seqA mutant membrane without success. A possible reason for this failure might be a profound modification of the outer membrane of the seqA mutant (as revealed by the fact that membrane from the mutant sediments more slowly than that from the wild type during ultracentrifugation). There is also a reduction in the content of OmpF protein. Moreover, one of the minor outer membrane proteins involved in partitioning of newly synthesized chromosomes, the ToiC (MukA) protein, was also found to be downregulated in the seqA mutant. This is also true of the hobH mutant grown in a high-osmolarity medium. Mutants of both seqA and hobH stop dividing after hyperosmotic shock, forming filaments (as observed in dam mutants).

Bacterial Outer Membrane Proteins

The Drosophila melanogaster homolog of ribosomal protein S18.

The sequence of the cDNA encoding the Drosophila melanogaster homolog of the human and rat small-subunit ribosomal protein, S18 (rpS18), is presented. The deduced 152-amino-acid (aa) sequence exhibits 76% identity to that of the human and rat rpS18 (152 aa), and is, like them, a member of the larger rpS13 family which includes archaebacterial, eubacterial and plant mitochondrial (mt) rpS13. The D. melanogaster rpS18 gene is single copy and maps at 56F, a chromosome region encompassing a previously characterised Minute locus, M(2)56F. The rpS18 gene gives rise to a single 700-nucleotide transcript present throughout development. A comparison of the rpS13 family members suggests that conservation is greatest at the N- and C-termini, whilst additional insertions are present in the Drosophila, mammalian and archaebacterial proteins relative to the eubacterial and plant mt proteins.

Amino Acid Sequence

The Drosophila melanogaster homolog of ribosomal protein L27a.

The amino acid sequence of the Drosophila melanogaster 60S ribosomal sub-unit protein, L27a, was deduced from the sequence of nucleotides in a recombinant cDNA. Ribosomal protein L27a has 149 amino acids with a molecular weight of 17,123 Daltons. Hybridisation of the cDNA to polytene chromosomes indicates the presence of a single gene on chromosome 3R at 87F/88A. There is a single mRNA for the protein of around 650 nucleotides in length. Drosophila ribosomal protein L27a is homologous to the rat and yeast L27a and to the other members of the L15 ribosomal protein family. There is also significant homology with an invertebrate motor protein and a Drosophila photoreceptor morphogenesis protein.

Amino Acid Sequence

Neuropsychological studies of auditory-visual fusion illusions. Four case studies and their implications.

A heard speech sound which is not the same as the synchronized speech sound can sometimes give rise to an illusory phonological percept. Typically, a heard /ba/ combines with a seen /ga/ to give the impression that /da/ has been heard (McGurk, H. and MacDonald, J. Nature Lond. 264, 746-748, 1976). We report the susceptibility to this illusion of four individuals with localized brain lesions affecting perceptual function. We compare their performance to that of ten control subjects and relate these findings to the efficiency of processing seen and heard speech in separate and combined modalities. The pattern of performance strongly suggests LH specialization for the phonological integration of seen and heard speech. The putative site of such integration can be effectively isolated from unilateral and from bilateral inputs and may be driven by either modality.

Adult

Bone loss during oestriol therapy in postmenopausal women.

In contrast to all other oestrogens examined thus far oestriol hemisuccinate (12 mg/day) did not prevent bone loss in 28 postmenopausal women. The average bone loss, however, was somewhat less than expected from placebo studies, while the bone loss achieved by a group taking 4-6 mg/day was equal to that achieved by previous placebo groups. To be an effective agent for prevention of post-menopausal osteoporosis oestriol would have to be prescribed in daily doses considerably in excess of 12 mg.

Adult

Bone response to termination of oestrogen treatment.

Forty-three oophorectomised patients were reviewed 8 years after their initial attendance at a research clinic investigating the aetiology and prevention of postmenopausal osteoporosis. Fifteen patients who had been treated with an oestrogen did not lose a significant amount of bone during the 8 years of therapy. Patients in the placebo-treated control group initially had bone loss of 2.6% per annum, which later fell to an average of 0.75% per annum. Fourteen patients who had been treated with oestrogen for the first 4 years lost no bone, but on withdrawal of oestrogen their bone mineral content fell over the next 4 years at an average rate of 2.5% per annum. 8 years after their initial attendance there was no significant difference between this group and patients who had received placebo for the full 8 years. The result of this study indicates that long-term prevention of bone loss by oestrogens has important medical, social, economic implications.

Bone and Bones

Six-month prognostic norms derived from studies of the Rorschach Prognostic Rating Scale.

The Rorschach Prognostic Rating Scale (RPRS) was introduced in 1951 by Klopfer. Kirkner, Wisham, and Baker. The predictions of Klopfer et al. are compared to the outcomes in four studies of the RPRS. The originalinterpretation is shown to predict higher percentages of success than revealed by the empirical studies. A second interpretation of the scale is proposed on the basis of the experimental data. This interpretation relates RPRS scores to the chance for substantial improvement within 30 weeks of once weekly therapy by client-centered, rational-emotive, desensitization, aversion, or traditional methods. For any given RPRS score, the chance for substantial improvement is approximately the same for every type of therapy, and increases as the RPRS score increases. The second interpretation is proposed in both tubular and algebraic forms as a stimulus to further research and clinical applications.

Humans

A guide to research on the Rorschach prognostic rating scale.

Research on the Rorschach Prognostic Rating Scale done in the last 25 years is summarized. The study results are organized into six topics: ability to predict outcome, numerical correlations, populations differentiated, populations not differentiated, specific therapies. The scale significantly predicts outcome and is thereby a valuable prognostic instrument.

Behavior Therapy