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T A Phillips

Publications and source records attributed to T A Phillips.

23 records · Page 2Linked to original sources
PubMed1980

Protein identifications on O'Farrell two-dimensional gels: locations of 55 additional Escherichia coli proteins.

The resolution of proteins from whole-cell homogenates by two-dimensional gel electrophoresis is sufficiently reproducible and precise to permit different laboratories to exchange information about them. To the previous total of 81 we add the locations of 55 Escherichia coli proteins determined with the aid of purified proteins and mutant strains supplied by many investigators. The criteria used to establish the identifications of protein spots include migration with marker proteins, altered position or amount in appropriate mutant or plasmid-carrying strains, physiological behavior, and peptide map pattern.

Bacterial Proteins↗
PubMedDate not supplied

Normal and dystrophic embryonic chicken pectoralis muscle cultures: I. Cell differentiation, protein synthesis, and enzyme levels.

Normal (line 200) and dystrophic (line 307) embryonic chicken pectoralis muscle cells were studied in cell culture over a period of 2 weeks. During the first 4 days, normal and dystrophic cultures exhibited similar developmental increases in the number of nuclei within multinucleated myotubes, however, dystrophic muscle cells degenerated approximately twice as fast as normal cells once the initial burst of myoblast fusion was complete. The apparent synthesis rate of nonmyofibrillar proteins was similar in normal aand dystrophic cells throughout development, but the apparent synthesis rates of myosin heavy chain and the myofibrillar protein fraction were 50%--90% higher in dystrophic muscle cultures once maturity had been reached (days 6--14). The specific activities of creatine kinase and phosphofructokinase were not affected by the dystrophic condition; however, specific activity of AMP-deaminase was depressed 25%--40% in the dystrophic muscle cultures.

AMP Deaminase↗
PubMedDate not supplied

Trophoblastic cell lines generated from tumour necrosis factor receptor-deficient mice reveal specific functions for the two tumour necrosis factor receptors.

In mice and humans, expression of the tumour necrosis factor receptor-1 (TNF-R1) gene in placental trophoblast cells is constitutive whereas expression of the TNF-R2 gene is developmentally programmed. In order to study the individual functions of TNF-R1 and -R2 in this lineage, cell lines were generated from placental explants of homozygous matings of gestation day 10 outbred mice (Swiss-Webster), TNF-R1-deficient (TNF-R1-/-) and TNF-R2-/- transgenic mice as well as the background strain for the TNF-R2-/- mice (WT, C57BL/6x129). All of the cells exhibited trophoblast markers; they contained cytokeratin intermediate filaments, expressed alkaline phosphatase activity and displayed transferrin receptors, but were negative for vimentin filaments and the macrophage marker, F4/80. Analysis of DNA by polymerase chain reaction demonstrated the expected TNF-R genotype in each line. In experiments testing the effects of recombinant mouse TNF-alpha (rmTNF-alpha) on viability and proliferation of the cell lines, rmTNF-alpha modestly but dose-dependently inhibited the growth of WT and TNF-R2-/- cells while having no effect on TNF-R1-/- cells. Actinomycin D-treated WT and, to a lesser extent, TNF-R2-/- cells, were more sensitive to growth inhibition than untreated cells whereas TNF-R1-/- cell responses remained unchanged. These data indicated that rmTNF-alpha inhibits growth of trophoblastic cells through TNF-R1 and that newly synthesized protein(s) provide partial protection against toxicity. In contrast to the receptor species-specific effects on cell growth exerted by rmTNF-alpha, both TNF-R mediated inhibition of alkaline phosphatase activity. Collectively, the observations support the postulate that receptor expression is the key factor which determines the nature and extent of TNF-alpha effects on trophoblast cell growth and function.

Alkaline Phosphatase↗
PubMedDate not supplied

Death-inducing tumour necrosis factor (TNF) superfamily ligands and receptors are transcribed in human placentae, cytotrophoblasts, placental macrophages and placental cell lines.

Human placentae and two of the cell types in placentae (cytotrophoblasts and macrophages) were examined by RT-PCR for transcripts of the eight TNF superfamily ligands known to induce death of activated immune cells, tumour cells, and virus-infected cells (TNFalpha, LT alpha, LT beta, FasL, TRAIL, TWEAK, LIGHT, 4-1BBL). Transcripts for all ligands were detected in term placenta but LT alpha and 4-1BBL were not detected in first trimester placenta. Although term cytotrophoblasts contained mRNAs specific for TNF alpha, LT alpha, TWEAK, and 4-1BBL, messages encoding LT beta, FasL, TRAIL, and LIGHT were absent. In term placental macrophages, messages for all ligands except 4-1BBL were present. Transcripts for the 14 receptors to which the ligands bind, six of which contain death-domains (TNFR1, Fas, DR3, DR4, DR5, DR6), were also identified using RT-PCR. Term and first trimester placentae contained transcripts for all receptors except 4-1BB. Although term cytotrophoblasts lacked receptor mRNA encoding 4-1BB and OPG, term placental macrophages lacked DcR1 and OPG. Detection of nearly all the death-inducing TNF superfamily ligands and their receptors in human placentae implies that these powerful cytokines contribute to programmed or activated cell death in this organ.

4-1BB Ligand↗