Griffith, O. Hayes H.
https://scholarsbank.uoregon.edu/xmlui/handle/1794/19413
2024-03-28T14:45:31ZIsotope effect on the paramagnetic resonance of triplet excitons
https://scholarsbank.uoregon.edu/xmlui/handle/1794/20212
Isotope effect on the paramagnetic resonance of triplet excitons
Buckman, T. D.; Griffith, O. H.; McConnell, H. M.
2 pages
1965-10-15T00:00:00ZPrion protein (PrP) synthetic peptides induce cellular PrP to acquire properties of the scrapie isoform
https://scholarsbank.uoregon.edu/xmlui/handle/1794/19934
Prion protein (PrP) synthetic peptides induce cellular PrP to acquire properties of the scrapie isoform
Kaneko, K.; Peretz, David; Pan, K. K.; Blochberger, T. C.; Wille, H.; Gabizon, R.; Griffith, O. H.; Cohen, F. E.; Baldwin, Michael A.; Prusiner, Stanley B.
Conversion of the cellular isoform of prion
protein (PrPc) into the scrapie isoform (PrPSc) involves an
increase in the /3-sheet content, diminished solubility, and
resistance to proteolytic digestion. Transgenetic studies argue
that PrPc and PrPSc form a complex during PrPScformation;
thus, synthetic PrP peptides, which mimic the conformational
pluralism of PrP, were mixed with PrPc to determine whether
its properties were altered. Peptides encompassing two a-helical
domains of PrP when mixed with PrPc produced a
complex that displayed many properties of PrPSc. The PrPcpeptide
complex formed fibrous aggregates and up to 65% of
complexed PrPc sedimented at 100,000 x g for 1 h, whereas
PrPc alone did not. These complexes were resistant to pro
teolytic digestion and displayed a high /3-sheet content. Un
expectedly, the peptide in a /3-sheet conformation did not form
the complex, whereas the random coil did. Addition of 2%
Sarkosyl disrupted the complex and rendered PrPc sensitive
to protease digestion. While the pathogenic AllTV mutation
increased the efficacy of complex formation, anti-PrP mono
clonal antibody prevented interaction between PrPc and pep
tides. Our findings in concert with transgenetic investigations
argue that PrPc interacts with PrPSc through a domain that
contains the first two putative a-helices. Whether PrPc-peptide
complexes possess prion infectivity as determined by
bioassays remains to be established.
5 pages
1995-11-01T00:00:00ZElectron optical benches for in-line and branched systems. A new bench designed for mirror-based aberration correction and low energy electron microscopy
https://scholarsbank.uoregon.edu/xmlui/handle/1794/19933
Electron optical benches for in-line and branched systems. A new bench designed for mirror-based aberration correction and low energy electron microscopy
Skoczylas, W. P.; Rempfer, G. F.; Griffith, O. H.
A review of electron optical bench literature is presented, and the designs of two optical benches
used by the authors are described. One bench was designed for testing individual electrostatic
electron lenses and in-line optical systems, for example, emission electron microscopes and
transmission electron microscopes. It has been in operation for many years. The second electron
optical bench is new. It is a branched system designed for several purposes: to study correction of
spherical and chromatic aberration with an electron mirror, and to gain experience with low energy
electron microscopy (LEEM) optics. The alignment of the electron optical support structure is
independent of the vacuum housing, and the bench is designed to be operated either horizontally or
vertically. As a demonstration of the performance of the new bench in the horizontal mode, a test
pattern on a silicon surface was imaged with LEEM optics.
6 pages
1994-10-01T00:00:00ZPhorbol ester-induced actin cytoskeletal reorganization requires a heavy metal ion, probably Zn2+.
https://scholarsbank.uoregon.edu/xmlui/handle/1794/19932
Phorbol ester-induced actin cytoskeletal reorganization requires a heavy metal ion, probably Zn2+.
Hedberg, K. K.; Birrell, G. B.; Griffith, O. H.
The cell-permeant heavy metal chelator N,N,N',Ntetrakis(
2-pyridylmethyl)ethylenediamine (TPEN) was
found to counteract phorbol ester-induced actin
reorganization in PTK2 and Swiss 3T3 cells. By us
ing fluorescence and the higher resolution tech
nique of photoelectron microscopy to monitor actin
patterns, 15-min pretreatment with 25-50 pM TPEN
was found to dramatically reduce actin alterations
resulting from subsequent phorbol ester treatment
in PTK2 cells. Similar results were obtained with
Swiss 3T3 cells using 50 mM TPEN for 1.5 h. Phorbol
ester-induced actin alterations are thought to de
pend on activation of protein kinase C (PKC). In
contrast to the phorbol ester effect, the PKC-independent
actin cytoskeletal disruption caused by
staurosporine and cytochalasin B was unaffected
by TPEN pretreatment. TPEN did not block phorbol
ester-induced activation of PKC in Swiss 3T3 cells,
as observed by the phosphorylation of the 80K PKC
substrate protein (MARCKS protein). TPEN also did
not inhibit partially purified PKC from Swiss 3T3
cells in an in vitro PKC-specific commercial assay.
To establish that the effect of TPEN is the removal
of metal ions and not some other nonspecific effect
of TPEN, a series of transition metal ions was
added at the end of the TPEN pretreatment. The
results indicate that the transient but dramatic
phorbol ester-induced reorganization of the actin
cytoskeleton in cultured cells depends on an inter
action of PKC with a heavy metal, probably zinc.
14 pages
1991-12-01T00:00:00Z