Sequence-specific double-strand cleavage of DNA by penta-N-methylpyrrolecarboxamide-EDTA·Fe(II)

In the presence of O2 and 5 mM dithiothreitol, penta-N-methylpyrrolecarboxamide-EDTA·Fe(II) [P5E·Fe(II)] at 0.5 µ M cleaves pBR322 plasmid DNA (50 µ M in base pairs) on opposite strands to afford discrete DNA fragments as analyzed by agarose gel electrophoresis. High-resolution denaturing gel electrophoresis of a 32P-end-labeled 517-base-pair restriction fragment containing a major cleavage site reveals that P5E·Fe(II) cleaves 3-5 base pairs contiguous to a 6-base-pair sequence, 5'-T-T-T-T-T-A-3' (4,323-4,328 base pairs). The major binding orientation of the pentapeptide occurs with the amino terminus at the adenine side of this sequence. In the presence of 5 mM dithiothreitol, 0.01 µ M P5E·Fe(II) converts form I pBR322 DNA at 0.22 µ M plasmid (1.0 mM in base pairs) to 40% form II, indicating the cleavage reaction is catalytic, turning over a minimum of nine times. This synthetic molecule achieves double-strand cleavage of DNA (pH 7.9, 25 degrees C) at the 6-base-pair recognition level and may provide an approach to the design of "artificial restriction enzymes.

Analytical comparisons of ablative nozzle materials final report, jun. 20, 1963 - nov. 20, 1964

Reaction kinetics ablation program to predict ablation performance of rocket nozzle heat protection material

Ocean shrimp report 1979 season

Statewide Pacific ocean shrimp, Pandalus jordani, landings totaled 2,237.7 mt (4,922,857 lb), down 3,745 mt (8,240,386 lb) from the 1978 catch of 5,983.3 mt (13,163,243 lb). The 1979 landings are the lowest since 1976 when 1,545.5 mt (3,400,191 lb) were landed. Area A (Eureka-Crescent City)landings dropped to 1,842.5 mt (4,053,605 lb) from 5,046.3 mt (11,101,895 lb) landed during the previous season. No landings were made in Area B-1 (Fort Bragg). Only 2.0 mt (4,385 lb) were reported caught in Area B-2 (Bodega Bay). Record landings of 393.1 mt (864,867 lb) were made in Area C (Morro Bay-Avila), surpassing the previous record of 90.4 mt (199,000 lb) landed in 1953. In Area A a record 71 vessels, 34 double-rigged and 37 single-rigged, shrimped during the season. Average catch per hour was a low .15 mt (338 lb) and .22 mt (490 1b) for single-rig and double-rig vessels, respectively. In Area C average catch per hour was .23 mt (508 lb) and .42 mt (924 lb) for single-rig and double-rig vessels, respectively. Area A shrimp catches were dominated by 1-year-old shrimp throughout most of the season. The age composition in Area C shifted predominately from 2-year-old shrimp in May and June to predominately 1-year-old shrimp in July, August, October, and November. Area A was closed for one month from July 15 to August 15 because closure criteria of less than .16 mt (350 lb) per hour for two consecutive weeks was met and year class composition exceeded 70% of 1-year-old shrimp. The season was closed October 14 when the catch per hour criterion was exceeded again. (18pp.

Quantum transport through single-molecule junctions with orbital degeneracies

We consider electronic transport through a single-molecule junction where the molecule has a degenerate spectrum. Unlike previous transport models, and theories a rate-equations description is no longer possible, and the quantum coherences between degenerate states have to be taken into account. We present the derivation and application of a master equation that describes the system in the weak-coupling limit and give an in-depth discussion of the parameter regimes and the new phenomena due to coherent on-site dynamics

Reversible strain effect on the magnetization of LaCoO3 films

The magnetization of ferromagnetic LaCoO3 films grown epitaxially on piezoelectric substrates has been found to systematically decrease with the reduction of tensile strain. The magnetization change induced by the reversible strain variation reveals an increase of the Co magnetic moment with tensile strain. The biaxial strain dependence of the Curie temperature is estimated to be below 4K/% in the as-grown tensile strain state of our films. This is in agreement with results from statically strained films on various substrates

Some taste substances are direct activators of G-proteins

Amphiphilic substances may stimulate cellular events through direct activation of G-proteins. The present experiments indicate that several amphiphilic sweeteners and the bitter tastant, quinine, activate transducin and Gi/Go-proteins. Concentrations of taste substances required to activate G-proteins in vitro correlated with those used to elicit taste. These data support the hypothesis that amphiphilic taste substances may elicit taste through direct activation of G-proteins