A snowpack model sensitivity study, observed changes of snow cover in the NOAA satellite dataset, and snow cover simulations from the Coupled Model Intercomparison Project phase 3 (CMIP3) multimodel dataset are used to provide new insights into the climate response of Northern Hemisphere (NH) snow cover. Under conditions of warming...
A genetic complementation system was developed
in which tobacco etch virus (TEV) polymerase (NIb)-
expressing transgenic plants or protoplasts were inoculated
with NIb-defective TEV mutants. A β-glucuronidase (GUS)
reporter gene integrated into the genomes of parental and four
mutant viruses was used to assay RNA amplification. Two
mutants (termed VNN...
Small RNAs, including microRNAs (miRNAs), small interfering RNAs
(siRNAs), and trans-acting siRNAs (tasiRNAs), control gene expression
and epigenetic regulation. Although the roles of miRNAs and
siRNAs have been extensively studied, their expression diversity
and evolution in closely related species and interspecific hybrids
are poorly understood. Here, we show comprehensive analyses...
Transacting siRNA (tasiRNA) biogenesis in Arabidopsis is initiated
by microRNA (miRNA) –guided cleavage of primary transcripts. In
the case of TAS3 tasiRNA formation, ARGONAUTE7 (AGO7)–
miR390 complexes interact with primary transcripts at two sites,
resulting in recruitment of RNA-DEPENDENT RNA POLYMERASE6
for dsRNA biosynthesis. An extensive screen for Arabidopsis mutants...
Despite renewed interest in the nature of limitations on maximum tree height, the mechanisms governing ultimate and species-specific height limits are not yet understood, but likely involve water transport dynamics. Tall trees experience increased risk of xylem embolism from air-seeding because tension in their water column increases with height due...
Desert, desert-steppe (Gobi) zone is the largest province by area (165,000 square kilometres) of Mongolia. The Gobi contains some 560 plant species, in 80 different vegetation associations (Swift, 1991). There are number of results of nutritive value of desert-steppe’s pasture grass. Mongolia’s dry climate means that pasture grasses have less...
This work sought to determine high pressure processing (HPP) effects on the activity of cathepsins B and D in the muscle of mackerel (Scomber scombrus) and horse mackerel (Trachurus trachurus). In mackerel, the cathepsin B activity decrease reached 40% at 450 MPa while in horse mackerel, low and intermediate pressures...
Insight into the dependence of benthic communities on biological and physical processes in nearshore pelagic environments, long considered a ``black box,'' has eluded ecologists. In rocky intertidal communities at Oregon coastal sites 80 km apart, differences in abundance of sessile invertebrates, herbivores, carnivores, and macrophytes in the low zone were...
Air trapped in glacial ice offers a means of
reconstructing variations in the concentrations of atmospheric
gases over time scales ranging from anthropogenic
(last 200 yr) to glacial/interglacial (hundreds of thousands of
years). In this paper, we review the glaciological processes by
which air is trapped in the ice and...
Wind-driven coastal ocean upwelling supplies nutrients to the
euphotic zone near the coast. Nutrients fuel the growth of phytoplankton,
the base of a very productive coastal marine ecosystem
[Pauly D, Christensen V (1995) Nature 374:255–257]. Because
nutrient supply and phytoplankton biomass in shelf waters are
highly sensitive to variation in...