Robert E. Zipkin

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In diverse organisms, calorie restriction slows the pace of ageing and increases maximum lifespan. In the budding yeast Saccharomyces cerevisiae, calorie restriction extends lifespan by increasing the activity of Sir2 (ref. 1), a member of the conserved sirtuin family of NAD(+)-dependent protein deacetylases. Included in this family are SIR-2.1, a(More)
In mammals, specific lipids and amino acids serve as crucial signaling molecules. In bacteria, conjugates of lipids and amino acids (referred to as lipoamino acids) have been identified and found to possess biological activity. Here, we report that mammals also produce lipoamino acids, specifically the arachidonyl amino acids. We show that the conjugate of(More)
N-Arachidonoyldopamine (NADA) was recently identified as an endogenous ligand for the vanilloid type 1 receptor (VR1). Further analysis of the bovine striatal extract from which NADA was isolated indicated the existence of substances corresponding in molecular mass to N-oleoyldopamine (OLDA), N-palmitoyldopamine (PALDA), and N-stearoyldopamine (STEARDA).(More)
Analogs and homologs of PDMP were synthesized, based on its structure (D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol). This compound had previously been found to block the synthesis of GlcCer (glucosylceramide). Increasing the acyl chain length from 10 to 16 carbon atoms greatly enhanced the efficacy of the enzyme inhibitor, as did the use of a(More)
The potent bioactive sphingolipid mediator, sphingosine-1-phosphate (S1P), is produced by 2 sphingosine kinase isoenzymes, SphK1 and SphK2. Expression of SphK1 is up-regulated in cancers, including leukemia, and associated with cancer progression. A screen of sphingosine analogs identified (2R,3S,4E)-N-methyl-5-(4'-pentylphenyl)-2-aminopent-4-ene-1,3-diol,(More)
This past decade has seen the identification of numerous conserved genes that extend lifespan in diverse species, yet the number of compounds that extend lifespan is relatively small. A class of compounds called STACs, which were identified as activators of Sir2/SIRT1 NAD+-dependent deacetylases, extend the lifespans of multiple species in a Sir2-dependent(More)
Sphingosine-1-phosphate is a potent sphingolipid mediator of diverse processes important for brain tumors, including cell growth, survival, migration, invasion, and angiogenesis. Sphingosine kinase 1 (SphK1), one of the two isoenzymes that produce sphingosine-1-phosphate, is up-regulated in glioblastoma and has been linked to poor prognosis in patients with(More)
In Aplysia neural tissue, the release and metabolism of arachidonic acid are stimulated by histamine or by activation of the identified L32 nerve cell circuit of the abdominal ganglion. Previously we found that histamine and intracellular stimulation of L32 cells, which are putatively histaminergic neurons, cause the production of(More)
Sphingolipid derivatives cause diverse effects towards the regulation of intracellular free Ca(2+) concentrations ([Ca(2+)](i)) in a multitude of nonexcitable cells. In the present investigation, the effect of C-8 ceramide-1-(2-cyanoethyl) phosphate (C1CP) on store-operated Ca(2+) (SOC) entry was investigated. C1CP evoked a modest increase in [Ca(2+)](i).(More)
A library of amino acid-fatty acid conjugates (elmiric acids) was synthesized and evaluated for activity as potential anti-inflammatory agents. The compounds were tested in vitro for their effects on cell proliferation and prostaglandin production, and compared with their effects on in vivo models of inflammation. LPS stimulated RAW 267.4 mouse macrophage(More)