The pathway of hepatitis C virus mRNA recruitment to the human ribosome.

Eukaryotic protein synthesis begins with mRNA positioning in the ribosomal decoding channel in a process typically controlled by translation-initiation factors. Some viruses use an internal ribosome entry site (IRES) in their mRNA to harness ribosomes independently of initiation factors. We show here that a ribosome conformational change that is induced upon hepatitis C viral IRES binding is necessary but not sufficient for correct mRNA positioning. Using directed hydroxyl radical probing to monitor the assembly of IRES-containing translation-initiation complexes, we have defined a crucial step in which mRNA is stabilized upon initiator tRNA binding. Unexpectedly, however, this stabilization occurs independently of the AUG codon, underscoring the importance of initiation factor-mediated interactions that influence the configuration of the decoding channel. These results reveal how an IRES RNA supplants some, but not all, of the functions normally carried out by protein factors during initiation of protein synthesis

Isotopes from Fecal Material Provides Evidence of Recent Diet of Prairie Deer Mice

Prairie deer mice are important predators in many agricultural systems, and through their diet they can help to regulate pest insect and weed populations. Our objective was to test whether fecal material is an effective means of detailing the foraging ecology of small mammals. We conducted three studies to evaluate the efficacy of this technique: 1) field-collected fecal material from unknown deer mice from late winter to early spring, 2) fecal material collected in an enclosure with mice fed a mix of C3 and C4 plant seeds, and 3) fecal material from tagged female mice in the field. We detected significant shifts in δ13C in one study and δ15N in another relative to spring thaw (δ13C: –13.34 vs. –10.72, P = 0.01, δ15N: 4.92 vs. 4.09, P = 0.03), a significant correlation between the relative amounts of two seed types and δ13C (slope = 5.46, SE = 1.82, P \u3c 0.01), and a significant decrease in δ15N due to nursing (4.57 ± 0.19 vs 3.28 ± 0.47, P = 0.02). Use of this technique will help to clarify foraging of this economically important species in agroecosystems

Isotopes from Fecal Material Provides Evidence of Recent Diet of Prairie Deer Mice

Prairie deer mice are important predators in many agricultural systems, and through their diet they can help to regulate pest insect and weed populations. Our objective was to test whether fecal material is an effective means of detailing the foraging ecology of small mammals. We conducted three studies to evaluate the efficacy of this technique: 1) field-collected fecal material from unknown deer mice from late winter to early spring, 2) fecal material collected in an enclosure with mice fed a mix of C3 and C4 plant seeds, and 3) fecal material from tagged female mice in the field. We detected significant shifts in δ13C in one study and δ15N in another relative to spring thaw (δ13C: –13.34 vs. –10.72, P = 0.01, δ15N: 4.92 vs. 4.09, P = 0.03), a significant correlation between the relative amounts of two seed types and δ13C (slope = 5.46, SE = 1.82, P \u3c 0.01), and a significant decrease in δ15N due to nursing (4.57 ± 0.19 vs 3.28 ± 0.47, P = 0.02). Use of this technique will help to clarify foraging of this economically important species in agroecosystems

Reply to Israel Carmi (2002): “Are the 14C Dates of the Dead Sea Scrolls Affected by Castor Oil Contamination?”

The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Can conservation complement agriculture?

Agriculture will need to produce at least 70% more food by 2050 to ensure global food security (FAO 2009). However, increased productivity has historically come with on-farm and societal costs such as increased soil erosion and nutrient run-off. While conservation is often considered separate from the needs of agriculture, recent research at ISU suggests that targeted conservation practices can positively impact management of farm land, especially for preventing soil erosion and nutrient run-off

Perspectives of Extension Agents and Farmers Toward Multifunctional Agriculture in the United States Corn Belt

We surveyed the perspectives of farmers, crop professionals, and Extension agents and found that they have positive perspectives concerning multifunctional agriculture, including a positive effect of a nearby prairie to cropland productivity. The survey was conducted in central Iowa and included individuals predominantly from Iowa involved in commodity research and production. Our results are preliminary and provide a baseline for further research into the perspectives of change agents in the U.S. Corn Belt. They also provide insight into similarities among key links in the diffusion of innovation chain

Chemically Related 4,5-Linked Aminoglycoside Antibiotics Drive Subunit Rotation in Opposite Directions

Dynamic remodelling of intersubunit bridge B2, a conserved RNA domain of the bacterial ribosome connecting helices 44 (h44) and 69 (H69) of the small and large subunit, respectively, impacts translation by controlling intersubunit rotation. Here we show that aminoglycosides chemically related to neomycin-paromomycin, ribostamycin and neamine-each bind to sites within h44 and H69 to perturb bridge B2 and affect subunit rotation. Neomycin and paromomycin, which only differ by their ring-I 6\u27-polar group, drive subunit rotation in opposite directions. This suggests that their distinct actions hinge on the 6\u27-substituent and the drug\u27s net positive charge. By solving the crystal structure of the paromomycin-ribosome complex, we observe specific contacts between the apical tip of H69 and the 6\u27-hydroxyl on paromomycin from within the drug\u27s canonical h44-binding site. These results indicate that aminoglycoside actions must be framed in the context of bridge B2 and their regulation of subunit rotation

Characterization of Aptamer-Protein Complexes by X-ray Crystallography and Alternative Approaches

Aptamers are oligonucleotide ligands, either RNA or ssDNA, selected for high-affinity binding to molecular targets, such as small organic molecules, proteins or whole microorganisms. While reports of new aptamers are numerous, characterization of their specific interaction is often restricted to the affinity of binding (KD). Over the years, crystal structures of aptamer-protein complexes have only scarcely become available. Here we describe some relevant technical issues about the process of crystallizing aptamer-protein complexes and highlight some biochemical details on the molecular basis of selected aptamer-protein interactions. In addition, alternative experimental and computational approaches are discussed to study aptamer-protein interactions.