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E S Davis

Publications and source records attributed to E S Davis.

10 recordsLinked to original sources
PubMed2004

c-fos Changes following an aggressive encounter in female California mice: a synthesis of behavior, hormone changes and neural activity.

Although there has been growing interest in the neuroanatomical and physiological mechanisms underlying aggressive behavior, little work has focused on possible mechanisms controlling natural plasticity in aggression. In the current study, we used naturally occurring changes in aggression level displayed by female Peromyscus californicus across the estrous cycle and parallel changes in c-fos expression to examine possible brain regions involved in mediating this plasticity. We found that c-fos expression was increased in females exposed to a conspecific female intruder compared with control females in numerous brain regions thought to be involved in the control of aggression. More importantly, we found that c-fos increased in the bed nucleus of the stria terminalis (BNST) and ventral lateral septum (LSv) only in the more aggressive, diestrous females, and not in the less aggressive, proestrous and estrous females. Conversely, c-fos increased in the medial amygdala (MeA) across all stages of estrus compared with controls, suggesting the MeA is not involved in mediating changes in individual levels of aggression. Moreover, we found correlations between several measures of aggression and c-fos expression in the BNST and LSv but not the MeA, again suggesting a role in mediating aggression plasticity for the former two but not the latter brain region. We further hypothesize that the BNST and the LSv may be involved more generally in mediating natural changes in aggression, such as increases often observed after individuals win aggressive interactions against conspecifics.

Aggression↗
PubMed2000

The Saccharomyces cerevisiae RDN1 locus is sequestered from interchromosomal meiotic ectopic recombination in a SIR2-dependent manner.

Meiotic ectopic recombination occurs at similar frequencies among many sites in the yeast genome, suggesting that all loci are similarly accessible to homology searching. In contrast, we found that his3 sequences integrated in the RDN1 (rDNA) locus were unusually poor participants in meiotic recombination with his3 sequences at other sites. We show that the low rate of meiotic ectopic recombination resulted from the poor ability of RDN1::his3 to act as a donor sequence. SIR2 partially repressed interchromosomal meiotic ectopic recombination at RDN1, consistent with its role in regulating recombination, gene expression, and retrotransposition within RDN1. We propose that RDN1 is physically sequestered from meiotic homology searching mechanisms.

Alleles↗
PubMed1997

Kids at risk.

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Adolescent↗
PubMed1992

A yeast cyclophilin gene essential for lactate metabolism at high temperature.

The cyclophilins are a family of ubiquitous eukaryotic proteins first identified by high affinity for cyclosporin A (CsA). The immunosuppressant and cytotoxic effects of CsA are thought to result from formation of a toxic complex between cyclophilin and CsA rather than from inhibition of cyclophilin function. The physiological role(s) of the cyclophilins is unknown. Cyclophilins have in vitro peptidylprolyl cistrans isomerase (PPIase) activity, and thus may be involved in protein folding in vivo. We have isolated a yeast cyclophilin gene, CPR3, which encodes a presumptive mitochondrial isoform. While CPR3 disruption mutants lack any phenotype at 30 degrees C, they are unable to grow on L-lactate at 37 degrees C. Disruptions of two other cyclophilin genes (CPR1, CPR2) and of FPR1, the gene encoding an FK506 binding protein with PPIase activity, do not affect growth on L-lactate at 37 degrees C. L-Lactate metabolism requires transcriptional induction of CYB2, the gene encoding flavocytochrome b2; cpr3 mutants induce transcription of this gene normally. This result demonstrates a conditional lethal phenotype for a cyclophilin mutation and presents a system for genetic and biochemical analysis of cyclophilin function.

Amino Acid Isomerases↗
PubMed1990

Expression of PiM-and PiZ-mutated forms of the human alpha 1-antitrypsin gene in transfected monkey COS1 cells.

The PiZ mutation of the gene coding for alpha 1-antitrypsin results in a serum deficiency of this protein leading to early onset emphysema and liver disease. The PiZ gene has a Z-specific point mutation in exon V together with a point mutation in exon III which is also present in some normal (PiM) individuals. There has thus far been no system to study the effects of PiZ point mutations in tissue culture. We constructed plasmids containing alpha 1-antitrypsin cDNA synthetically altered at either exon III or exon V mutation sites and linked to simian virus 40 promoter sequences. Such constructs with the exon V mutation were transfected into monkey COS1 cells followed by analysis of expression of alpha 1-antitrypsin gene products. COS1 cells normally synthesize virtually no alpha 1-antitrypsin mRNA or protein. alpha 1-Antitrypsin mRNA is transcribed at high levels in cells transfected with either M or Z plasmids. Immunologic staining of COS1 cells within 48 h of transfection localizes alpha 1-antitrypsin protein to specific regions of the cytoplasm. This extranuclear localization is also observed with human HepG2 hepatoma cells, which synthesize alpha 1-antitrypsin at high levels, and with human SK-Hep1 hepatoma cells transfected with an M plasmid. The cloned synthetically altered alpha 1-antitrypsin genes provide a system for dissecting contributions of distinct point mutations to the pathological effects of the PiZ protein.

Animals↗
PubMed1982

"No two fields ever grow grass the same way": assessment of conservation abilities in the elderly.

Within the past ten years, standard cognitive assessment procedures, including Piagetian tasks, have often been used with the elderly. The present paper examines several possible difficulties in interpreting the results of studied which employ Piagetian tasks, especially conservation tasks, with older individuals. First, it is noted that Piaget's clinical method allows more flexibility in the assessment of competence than do the more quantifiable, American techniques. However, most of the research studies suggesting a cognitive decline with age have utilized rigid assessment procedures. Second, the paper examines the possibility of task misinterpretation by the elderly. Examples from recent research, in which older persons stressed reality-based problem solving strategies rather than the more abstract strategies traditionally associated with Piagetian tasks, are provided. The possibility of cognitive change instead of cognitive decline with age is discussed, and the importance of utilizing procedures which can measure this change is stressed.

Aged↗
PubMed1981

Solute concentration affects bradykinin-mediated increases in renal prostaglandin E2.

The effects of solute concentration on the bradykinin-mediated increase in inner medullary slice prostaglandin E2 (PGE2) synthesis were investigated. PG content was determined by specific RIA. Bradykinin stimulation was prevented by the addition of the following solutes to Krebs buffer: 1.0 M urea, 0.5 or 1.0 M NaCl, 0.5 or 1.0 M mannitol, 1.0 M urea plus 0.5 M NaCl, or 1.0 M mannitol plus 0.5 M NaCl. By contrast, basal PGE2 synthesis was increased by 1.0 M mannitol or by 1.0 M mannitol plus 0.5 M NaCl, but decreased by 1.0 M urea. Urea elicited a concentration-dependent, reversible inhibition of bradykinin stimulation, with 0.01 M urea being the lowest effective concentration. By contrast, basal PGE2 synthesis was only reduced at a urea concentration greater than 0.6 M. Arachidonic acid-mediated increases in both PGE2 and PGF2 alpha synthesis were not prevented by 1.0 M urea. The latter suggests that neither PG endoperoxide synthetase nor PG endoperoxide E isomerase are inhibited by urea. The data indicate that different hypertonic solutions have different effects on basal PG production, but all inhibit bradykinin stimulation.

Animals↗