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P R Russell

Publications and source records attributed to P R Russell.

10 recordsLinked to original sources
PubMed1999

IL-2 mediates protection against abscess formation in an experimental model of sepsis.

Little is known regarding the mechanism by which T cells control intraabdominal abscess formation. Treating animals with polysaccharide A (PS A) from Bacteroides fragilis shortly before or after challenge protects against abscess formation subsequent to challenge with different abscess-inducing bacteria. Although bacterial polysaccharides are considered to be T cell-independent Ags, T cells from PS A-treated animals mediate this protective activity. In the present study, we demonstrate that CD4+ T cells transfer PS A-mediated protection against abscess formation, and that a soluble mediator produced by these cells confers this activity. Cytokine mRNA analysis showed that T cells from PS A-treated animals produced transcript for IL-2, IFN-gamma, and IL-10, but not for IL-4. The addition of IL-2-specific Ab to T cell lysates taken from PS A-treated animals abrogated the ability to transfer protection, whereas the addition of Abs specific for IFN-gamma and IL-10 did not affect protection. Finally, administration of rIL-2 to animals at the time of bacterial challenge prevented abscess formation in a dose-dependent manner. These data demonstrate that PS A-mediated protection against abscess formation is dependent upon a CD4+ T cell-dependent response, and that IL-2 is essential to this immune mechanism.

Abdominal Abscess↗
PubMed1985

Transcription of the triose-phosphate-isomerase gene of Schizosaccharomyces pombe initiates from a start point different from that in Saccharomyces cerevisiae.

Gene tpi, encoding the glycolytic enzyme triose phosphate isomerase (TPI) from the fission yeast Schizosaccharomyces pombe was cloned by complementation of a Saccharomyces cerevisiae tpil mutant. Nucleotide sequence analysis of the cloned gene revealed a single open reading frame (ORF) encoding a protein 59% homologous to S. cerevisiae TPI. The gene has a very high codon usage bias. Messenger RNA synthesis initiates at two points located 38 and 44 nucleotides downstream from a TATA box promoter sequence. In S. cerevisiae, transcription of this S. pombe gene initiates about 26 nucleotides downstream from the S. pombe start points. This observation indicates that the two yeasts have diverged in the mechanism which determines the 5' end of the messenger RNA relative to the TATA box. It appears that in some respects the transcription initiation mechanism of S. pombe more closely resembles that of higher eukaryotes than does the S. cerevisiae mechanism.

Amino Acid Sequence↗
PubMed1983

Evolutionary divergence of the mRNA transcription initiation mechanism in yeast.

The promoters of eukaryotic genes are being increasingly defined through the identification of consensus DNA sequences, by mutational analysis, and by in vitro and in vivo studies of transcription. Whereas the TATA sequence (Goldberg-Hogness box) has been largely conserved among protein encoding genes (transcribed by RNA polymerase II) of eukaryotes, there is some evidence that other structural and functional determinants of mRNA transcription are not conserved between species. I report there an in vivo comparative analysis of the transcription initiation systems of the budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharmyces pombe (which can both be transformed by identical plasmids). I have found no instance in which a gene is transcribed in the same fashion in both yeasts. Instead, I have found that the in vivo transcription starting points for many different yeast genes are determined by the cell in which it is transcribed rather than its gene structure alone. The evidence also suggests that the divergence of the transcription initiation system may partly involve the mechanism or structure which determines the distance from the TATA consensus sequence to the site of transcription initiation.

Base Sequence↗
PubMed1983

The primary structure of the alcohol dehydrogenase gene from the fission yeast Schizosaccharomyces pombe.

We have cloned and sequenced the alcohol dehydrogenase gene of the fission yeast Schizosaccharomyces pombe. The gene was isolated by transformation and complementation of a Saccharomyces cerevisiae strain which lacked functional alcohol dehydrogenase with an S. pombe gene bank constructed in the autonomously replicating yeast plasmid YEp13. Southern hybridization analysis indicates that S. pombe contains only one alcohol dehydrogenase gene. The structural region of the gene is 50% homologous to the alcohol dehydrogenase encoding genes of the budding yeast S. cerevisiae. The gene exhibits a very strong codon usage bias; with the set of predominantly used codons generally resembling that which S. cerevisiae employs preferentially. All of the differences in codon usage bias between S. pombe and S. cerevisiae are in the direction of greater G + C content in S. pombe codons. It is argued that this observation supports the hypothesis that selection toward uniform codon-anticodon binding energies contributes to codon usage bias and that the optimum binding energy is, on the average, higher in S. pombe than S. cerevisiae.

Alcohol Dehydrogenase↗
PubMed1982

Nitrogen fixation (nif) genes and large plasmids of Rhizobium japonicum.

The location of structural nitrogen-fixation genes was determined for the slow- and fast-growing types of Rhizobium japonicum. Slow-growing R. japonicum strains do not harbor structural nif genes, homologous to nifD and nifH, on large plasmids (100 to 200 megadaltons). In contrast, all fast-growing R. japonicum strains, except PRC194, contain structural nif genes on large plasmids.

DNA, Recombinant↗
PubMed1982

Structure of the Schizosaccharomyces pombe cytochrome c gene.

The cytochrome c gene of the fission yeast Schizosaccharomyces pombe has been cloned by using the Saccharomyces cerevisiae iso-1-cytochrome c gene as a molecular hybridization probe. The DNA sequence and the 5' termini of the mRNA transcripts of the gene have been determined. The DNA sequence has confirmed, with two exceptions, the previously determined protein sequence. The nonrandom distribution of silent third base differences which was observed between the two cytochrome c genes of S. cerevisiae does not extend to the S. pombe cytochrome c gene, suggesting that there are no constraints other than protein function and codon usage which have acted to conserve the cytochrome DNA sequences of the two yeasts. Introduction of the S. pombe cytochrome c gene on a yeast plasmid into a S. cerevisiae mutant which lacked functional cytochrome c transformed that recipient strain for the ability to grow on a nonfermentable carbon source. This implies that the S. pombe cytochrome c gene has all the regulatory signals which are required for its expression in S. cerevisiae, and that none of the amino acid differences between the cytochrome c proteins of the two yeasts has a drastic effect on the function of the protein in vivo.

Ascomycota↗
PubMed1976

Evidence for more than one Ca2+ transport mechanism in mitochondria.

The active transport and internal binding of the Ca2+ analogue Mn2+ by rat liver mitochondria were monitored with electron paramagnetic resonance. The binding of transported Mn2+ depended strongly on internal pH over the range 7.7-8.9. Gradients of free Mn2+ were compared with K+ gradients measured on valinomycin-treated samples. In the steady state, the electrochemical Mn2+ activity was larger outside than inside the mitochondria. The observed gradients of free Mn2+ and of H+ could not be explained by a single "passive" uniport or antiport mechanism of divalent cation transport. This conclusion was further substantiated by observed changes in steady-state Ca2+ and Mn2+ distributions induced by La3+ and ruthenium red. Ruthenium red reduced total Ca2+ or Mn2+ uptake, and both inhibitors caused release of divalent cation from preloaded mitochondria. A model is proposed in which divalent cations are transported by at least two mechanisms: (1) a passive uniport and (2) and active pump, cation antiport or anion symport. The former is more sensitive to La3+ and ruthenium red. Under energized steady-state conditions, the net flux of Ca2+ or Mn2+ is inward over (1) and outward over (2). The need for more than one transport system inregulating cytoplasmic Ca2+ is discussed.

Acetates↗
PubMed1975

Quantitative magnetic resonance studies of manganese uptake by mitochondria.

The uptake of the paramagnetic ion manganese by rat liver mitochondria is studied by electron paramagnetic resonance (EPR) spectroscopy. Emphasis is placed on: (a) obtaining accurate EPR quantitation of intramitochondrial manganese fractions previously described (Gunter, T. E., and J. S.Puskin, 1972, Biophys. J. 12:625) (b) establishing competition for intramitochondrial binding between one of these fractions and calcium, (c) demonstrating the effects of substrate and ATP concentrations on each fraction observed through EPR, and (d) demonstrating the effect of inorganic phosphate (Pi) concentration and pH on each fraction.

Adenosine Triphosphate↗