The nonproteinogenic amino acid enduracididine is a critical component of the mannopeptimycins, cyclic glycopeptide antibiotics with activity against drug-resistant pathogens, including methicillin-resistant Staphylococcus aureus. Enduracididine is produced in Streptomyces hygroscopicus by three enzymes, MppP, MppQ, and MppR. On the basis of primary sequence analysis, MppP and MppQ are pyridoxal 5'-phosphate-dependent...
This paper presents a model for deterministic parsing which was designed to simplify the task or writing and understanding a deterministic grammar. While retaining structures and operations similar to those or Marcus's PARSIFAL parser [Marcus 80] the grammar language incorporates the following changes. (1) The use or productions operating in...
Plankton tows from the northern California Current constrain biological and physical
influences on living planktonic foraminifera. In this region, the dominant factors controlling the
size and distribution of symbiotic and asymbiotic species are light and food. Food decreases offshore.
Light, needed for symbiont photosynthesis, increases offshore as water turbidity lessens....
We have used the vanadium concentration in cleaned foraminiferal calcite as a tracer
of seawater V changes in the past. Since the benthic flux of vanadium is sensitive to the redox potential
of sediments, changes in the vanadium concentration of seawater should be a reflection of
changes that control the...
Mixed conifer and hardwood stands in southwestern Oregon were studied to explore the hypothesis that competition effects on individual-tree growth and survival will differ according to the species comprising the competition measure. Likewise, it was hypothesized that competition measures should extrapolate best if crown-based surrogates are given preference over diameter-based...
Dai 1 y temperature and sa 1 in i ty conditions measured in the surf at Agate Beach, Oregon, are given and summarized by 15 day periods, with the range, mean and standard deviation of each period indicated. Conditions in 1970 are briefly compared to those observed in 1968 and...
Many ocean regions important to the global carbon budget, including the equatorial Pacific Ocean, have low chlorophyll concentrations despite high levels of conventional nutrients. Iron may instead by the limiting nutrient, and elevated input of terrigenous Fe during windy glacial episodes has been hypothesized to stimulate oceanic productivity through time...
In order to quantify changes in export production and carbonate dissolution over the past 1 Myr in the
central equatorial Pacific Ocean we analyzed Ba, P, Al, Ti, and Ca in 1106 samples from five piston cores gathered from
5°S to 4°N at 140°W. We focused on Ba/Ti, Al/Ti, and...
The sensitivity of the tropics to climate change, particularly the amplitude of glacial‐to‐interglacial changes in sea surface temperature (SST), is one of the great controversies in paleoclimatology. Here we reassess faunal estimates of ice age SSTs, focusing on the problem of no‐analog planktonic foraminiferal assemblages in the equatorial oceans that...
