31 research outputs found
Kinetic comparisons of amniotic fluid inactive renin and renal renin using synthetic and human renin substrates
Inactive renin has been isolated from pooled amniotic fluid and purified ~642-fold. Prior to activation the isolates has ~4% of the activity found after activation. The observation is similar to that reported for inactive renin from chorionic cell culture and suggests a placental origin of amniotic fluid inactive renin.Using plasma from an estrogen-treated woman, renin substrate was recovered free of renin and inactive renin and a portion was separated into NMW and HMW components. The NMW form constituted ~93% and the HMW form ~7% of the renin substrate.Amniotic fluid inactive renin was used for determinations of enzyme-substrate kinetics with the pooled, NMW, and HMW plasma substrate and tetradecapeptide synthetic substrate, and the results were compared to similar determinations using standard renal renin. Using synthetic substrate, the kinetics of renal renin and amniotic fluid inactive renin before and after activation were similar. The kinetics of renal renin with pooled, NMW, and HMW plasma substrate were also similar.Amniotic fluid inactive renin had a lower Km with pooled than with NMW substrate, however, which resulted from a significantly smaller Km with HMW component. Although the affinity constants with pooled substrate were not different for renin and inactive renin, the Km of inactive renin was significantly less with the HMW component of plasma renin substrate.The observation are compatible with a role for placental inactive renin in normal pregnancy and suggest the possibility of a further role in hypertensive pregnancy.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25955/1/0000021.pd
Influenza A (H3N2) Outbreak, Nepal
Worldwide emergence of variant viruses has prompted a change in the 2005–2006 H3N2 influenza A vaccine strain
Alterations in the neuropeptide galanin system in major depressive disorder involve levels of transcripts, methylation, and peptide
Major depressive disorder (MDD) is a substantial burden to
patients, families, and society, but many patients cannot be
treated adequately. Rodent experiments suggest that the
neuropeptide galanin (GAL) and its three G protein-coupled
receptors, GAL1–3, are involved in mood regulation. To explore
the translational potential of these results, we assessed the
transcript levels (by quantitative PCR), DNA methylation status
(by bisulfite pyrosequencing), and GAL peptide by RIA of the GAL
system in postmortem brains from depressed persons who had
committed suicide and controls. Transcripts for all four members
were detected and showed marked regional variations, GAL and
galanin receptor 1 (GALR1) being most abundant. Striking
increases in GAL and GALR3 mRNA levels, especially in the
noradrenergic locus coeruleus and the dorsal raphe nucleus, in
parallel with decreased DNA methylation, were found in both male
and female suicide subjects as compared with controls. In
contrast, GAL and GALR3 transcript levels were decreased, GALR1
was increased, and DNA methylation was increased in the
dorsolateral prefrontal cortex of male suicide subjects,
however, there were no changes in the anterior cingulate cortex.
Thus, GAL and its receptor GALR3 are differentially methylated
and expressed in brains of MDD subjects in a region- and sex-
specific manner. Such an epigenetic modification in GALR3, a
hyperpolarizing receptor, might contribute to the dysregulation
of noradrenergic and serotonergic neurons implicated in the
pathogenesis of MDD. Thus, one may speculate that a GAL3
antagonist could have antidepressant properties by disinhibiting
the firing of these neurons, resulting in increased release of
noradrenaline and serotonin in forebrain areas involved in mood
regulation
Integral Membrane Protein Fragment Recombination after Transfer from Nanolipoprotein Particles to Bicelles
A new
method for the measurement of membrane protein oligomer association
is described. Two engineered fragments of bacteriorhodopsin, which
are known to spontaneously associate in bicelles, were expressed in
nanolipoprotein particles (NLPs or nanodiscs) using an <i>Escherichia
coli</i> S30 cell-free synthesis system. When separately
prepared NLPs containing the fragments were mixed, fragment
association did not occur, indicating that the apolipoprotein edge
blocks transfer between NLPs. However, when bicelles were added to
this mixture, fragment association was detected by disulfide cross-linking.
The rate of cross-linking was consistent with previously published
equilibrium and kinetic parameters. Characterization of the NLP/bicelle
mixture by dynamic light scattering and fluorescence spectroscopy
indicates that the NLP bilayer transfers to bicelles in a simple reversal
of the synthesis of NLPs from bicelles. These experiments validate
using cell-free synthesis of membrane proteins in NLPs, followed by
treatment with bicelles, as a method for measuring oligomerization
of integral membrane protein subunits in a bilayer-like environment