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Biomedical subjects

M Little

Publications and source records attributed to M Little.

At least 19 recordsLinked to original sources
PubMed1992

A vector for the removal of deletion mutants from antibody libraries.

To reduce the number of deletion mutants from antibody (Ab) libraries that had been amplified by PCR from peripheral blood lymphocytes, we constructed the Ab expression vector, pLAB, in which DNA coding for a single-chain Ab was inserted into the gene encoding beta-lactamase (Bla) at the 3'-terminus of its signal sequence. After transforming Escherichia coli with this vector, a fusion protein with a functional Bla domain was produced that was able to protect the bacteria from the action of ampicillin (Ap). Libraries can therefore be usefully propagated with this vector, since only those clones carrying inserts that are in frame with Bla will survive Ap selection, while others that carry out-of-frame deletions or internal stop codons are eliminated.

Amino Acid Sequence↗
PubMed1992

p34cdc2 kinase-mediated release of lamins from nuclear ghosts is inhibited by cAMP-dependent protein kinase.

During mitosis the lamins are found in a hyperphosphorylated and soluble state. p34cdc2 kinase (MPF), a protein kinase complex with a pivotal role during mitosis, has been found to phosphorylate the lamins and, in some cases, though not all, to cause depolymerization of the lamina in vitro. Due to the variety of protein interactions in the lamina, there is a probable requirement for multiple enzyme activities to effect its breakdown in mitosis. Using nuclear ghosts as substrate, we have fractionated a Xenopus mitotic extract into a lamin-releasing fraction (p34cdc2 kinase) and a fraction that inhibits p34cdc2 kinase-mediated lamin release if the nuclear ghosts are first preincubated in it. The lamin-release-inhibiting activity in the p34cdc2 kinase-depleted mitotic extract is, in turn, inhibited if PKI, a protein kinase inhibitor specific for PKA, is included in the preincubation reaction mixture. Furthermore, a similar degree of inhibition can be achieved by using purified PKA to preincubate the nuclear ghosts. This suggests that dephosphorylation of PKA substrate sites is necessary for lamin depolymerization.

Animals↗
PubMed1992

Resolving conflict.

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Conflict, Psychological↗
PubMed1991

A surface expression vector for antibody screening.

To select specific antibodies (Ab) from large recombinant libraries using small amounts of antigen, we have constructed a phagemid that expresses a single-chain Ab fused to pIII, a coliphage protein product of gene III that initiates infection by binding to F pili. Surprisingly, the production of the fusion protein (Ab::pIII) was induced by wild-type (wt) phage fd in the absence of IPTG. Ab::pIII was identified by a monoclonal Ab to an epitope in the linker sequence between the heavy and light chains, and by antisera to their N-terminal sequences. It is able to bind antigen and be assembled into infectious phagemid particles that can be enriched on columns of immobilised antigen. The phagemid DNA is even smaller than that of wt fd phages and can easily be propagated in plasmid form. Most importantly, its Ab::pIII-encoding gene can be tightly repressed so that Ab libraries can be amplified without risk of being dominated by deletion mutants. After induction, however, large quantities of the fusion protein can be produced, thus greatly facilitating its analysis.

Amino Acid Sequence↗
PubMed1991

Imperialism, colonialism and the new science of nutrition: the Tanganyika experience, 1925-1945.

The League of Nations is generally remembered as the ineffective forerunner of the United Nations. It is seldom acknowledged for the groundbreaking work it sponsored in the 1920s and 30s in the then new science of nutrition. The League's work resulted in the first internationally-recognized table of dietary standards. The information collected through the League's research was applied primarily to improving the health of industrial workers in European nations. However, member nations, such as Great Britain, were required to conduct nutrition surveys in their overseas territories. British administrative policies in Africa were a key factor in precipitating the shortages for at least one ethnic group, the Sukuma of northwest Tanganyika. The Sukuma were unable to maintain their precolonial subsistence system under the pressure of colonial taxation. The gradual degeneration of subsistence production altered the quality of the Sukuma diet. Colonial medical officers assumed that these crisis diets were the "traditional" African diets. This assumption combined with the general racist attitudes of the period precluded the application of the League's research to African populations under British administration.

History, 20th Century↗
PubMed1991

Targeting recombinant antibodies to the surface of Escherichia coli: fusion to a peptidoglycan associated lipoprotein.

To target recombinant antibodies to the surface of Escherichia coli, we have fused single-chain variable domains to its peptidoglycan associated lipoprotein (PAL). The fusion protein was able to bind antigen and was tightly bound to the murein layer of the cell envelope. Antibody-PAL had little effect on cell growth and viability. In contrast, the expression of single chain antibody alone eventually resulted in cell lysis. Immunofluorescence studies on unfixed cells showed that functional antibodies were accessible at the surface of intact bacteria. This could provide a means of isolating single cells producing specific antibodies from libraries in E. coli by fluorescence assisted cell sorting (FACS). Pal fusions may also be of general interest for the presentation of proteins at the surface of E. coli as, for example, in the production of live vaccines.

Amino Acid Sequence↗
PubMed1991

Tired of AIDS.

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Acquired Immunodeficiency Syndrome↗
PubMed1991

Compulsive sex.

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Adult↗
PubMed1991

America's secret.

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Adjustment Disorders↗