[PSI(+)] is a prion (infectious protein) of Sup35p, a subunit of the Saccharomyces cerevisiae translation termination factor. We isolated a dominant allele, SSA1-21, of a gene encoding an Hsp70 chaperone that impairs [PSI(+)] mitotic stability and weakens allosuppression caused by [PSI(+)]. While [PSI(+)] stability is normal in strains lacking SSA1, SSA2, or both, SSA1-21 strains with a deletio...

Amyloid fibers play important roles in many human diseases and natural biological processes and have immense potential as novel nanomaterials. We explore the physical properties of polymorphic amyloid fibers formed by yeast prion protein Sup35. Amyloid fibers that conferred distinct prion phenotypes ([PSI(+)]), strong (S) versus weak (W) nonsense suppression, displayed different physical proper...

The structure of (S)-N,N'-di-tert-butyl-2-[N-(1-phenylethyl)benzamido] malonamide contains two fragments of a polypeptide chain. This compound therefore can be taken as a model substance for details of protein conformation. In the crystalline state one peptide chain of the model molecule incorporates a hydrogen bond between two adjacent nitrogen atoms in the backbone. The acceptor for the hydro...

We observe signals for the decays psi(3770) --> XJ/psi from data acquired with the CLEO detector operating at the CESR e+ e- collider with square root of s = 3773 MeV. We measure the following branching fractions Beta(psi(3770) --> XJ/psi and significances: (189 +/- 20 +/- 20) x 10(-5) (11.6sigma) for X = pi+ pi-, (80 +/- 25 +/- 16) x 10(-5) (3.4sigma) for X = pi0 pi0, and (87 +/- 33 +/- 22) x ...

The cyanobacterium Synechococcus PCC 7942 grown under iron starvation assembles a supercomplex consisting of a trimeric Photosystem I (PSI) complex encircled by a ring of 18 CP43' or IsiA complexes. It has previously been shown that PSI of Synechococcus PCC 7942 contains less special long-wavelength ('red') chlorophylls than PSI of most other cyanobacteria. Here we present a comparative analysi...

Green plant photosystem I (PSI) consists of at least 18 different protein subunits. The roles of some of these protein subunits are not well known, in particular those that do not occur in the well characterized PSI complexes from cyanobacteria. We investigated the spectroscopic properties and excited-state dynamics of isolated PSI-200 particles from wild-type and mutant Arabidopsis thaliana pl...

PURPOSE To compare the depth of sedation determined by Ramsay sedation scale (RSS) with electroencephalogram-based bispectral index (BIS) and patient state index (PSI). MATERIALS AND METHODS Fifty mechanically ventilated cardiac surgical patients undergoing propofol and morphine sedation were assessed hourly for up to 6 hours or until tracheal extubation using the BIS, PSI, and RSS. Correlati...

Photosystem I (PSI) of higher plants contains 18 subunits. Using Arabidopsis En insertion lines, we have isolated knockout alleles of the genes psaG, psaH2, and psaK, which code for PSI-G, -H, and -K. In the mutants psak-1 and psag-1.4, complete loss of PSI-K and -G, respectively, was confirmed, whereas the residual H level in psah2-1.4 is due to a second gene encoding PSI-H, psaH1. Double muta...

Recent evidence from leaves and stems indicates that gradients in water potential (psi(w)) necessary for water movement through growing tissues are larger than previously assumed. Because growth is sensitive to tissue psi(w) and the behavior of these gradients has not been investigated in transpiring plants, we examined the water status of all the growing and mature vegetative tissues of maize ...

Photosystems (PS) I and II activities depend on their light-harvesting capacity and trapping efficiency, which vary in different environmental conditions. For optimal functioning, these activities need to be balanced. This is achieved by redistribution of excitation energy between the two photosystems via the association and disassociation of light-harvesting complexes (LHC) II, in a process kn...