Crustaceans have long been used for peptide research. For example, the process of neurosecretion was first formally demonstrated in the crustacean X-organ-sinus gland system, and the first fully characterized invertebrate neuropeptide was from a shrimp. Moreover, the crustacean stomatogastric and cardiac nervous systems have long served as models for understanding the general principles governing neural circuit functioning, including modulation by peptides. Here, we review the basic biology of crustacean neuropeptides, discuss methodologies currently driving their discovery, provide an overview of the known families, and summarize recent data on their control of physiology and behavior.

Arginine methylation can affect both nucleocytoplasmic transport and protein-protein interactions of RNAbinding proteins. These effects are seen in cells that lack the yeast hnRNP methyltransferase (HMT1), raising the question of whether effects on specific proteins are direct or indirect. The presence of multiple arginines in individual methylated proteins also raises the question of whether overall methylation or methylation of a subset of arginines affects protein function. We have used the yeast mRNA-binding protein Npl3 to address these questions in vivo. Matrix-assisted laser desorption/ionization Fourier transform mass spectrometry was used to identify 17 methylated arginines in Npl3 purified from yeast: whereas 10 Arg-Gly-Gly (RGG) tripeptides were exclusively dimethylated, variable levels of methylation were found for 5 RGG and 2 RG motif arginines. We constructed a set of Npl3 proteins in which subsets of the RGG arginines were mutated to lysine. Expression of these mutant proteins as the sole form of Npl3 specifically affected growth of a strain that requires Hmt1. Although decreased growth generally correlated with increased numbers of Arg-to-Lys mutations, lysine substitutions in the N terminus of the RGG domain showed more severe effects. Npl3 with all 15 RGG arginines mutated to lysine exited the nucleus independent of Hmt1, indicating a direct effect of methylation on Npl3 transport. These mutations also resulted in a decreased, methylation-independent interaction of Npl3 with transcription elongation factor Tho2 and inhibited Npl3 selfassociation. These results support a model in which arginine methylation facilitates Npl3 export directly by weakening contacts with nuclear proteins.Protein-arginine methylation by type I methyltransferases, which add one or two methyl groups to one of the guanidino nitrogens of arginine, has been shown to affect a number of eukaryotic processes including protein transport, transcription, and cell signaling (reviewed in Refs. 1-3). Although many substrates for arginine methyltransferases are RNA-binding proteins, to date methylation has been shown to have only relatively minor effects on the affinity of target proteins for RNA (4 -7). Many studies, however, point to a role for arginine methylation in modulating protein-protein interactions (reviewed in Ref.2). The observation of both positive and negative effects of arginine methylation on protein-protein interactions has led to models for roles of arginine methylation in cell signaling and transcription, through the modification of histones, RNA-binding proteins, signaling proteins, and proteins involved in transcription (1,2,8).Over 25 years ago heterogeneous nuclear ribonucleoproteins (hnRNPs) 1 were found to contain the majority of asymmetric dimethylarginine in HeLa cell nuclei (9). Subsequent studies of hnRNPs and related messenger RNA (mRNA)-binding proteins have revealed an intricate and evolving picture of nuclear mRNA metabolism from transcription to processing to nuclear export (10). Methylation has bee...

During the first six years of atmospheric CO 2 enrichment at the Duke Forest free-air CO 2 enrichment (FACE) experiment, an additional sink of 52 Ϯ 16 g C·m Ϫ2 ·yr Ϫ1 accumulated in the forest floor (O-horizon) of the elevated CO 2 treatment relative to the ambient CO 2 control in an aggrading loblolly pine (Pinus taeda L.) forest near Chapel Hill, North Carolina, USA. The experiment maintained an atmospheric CO 2 concentration 200 L/L above ambient levels in replicated (n ϭ 3) FACE rings throughout the six-year period. This CO 2 -induced C sink was associated with greater inputs of organic matter in litterfall and fine-root turnover. There was no evidence that microbial decomposition was altered by the elevated CO 2 treatment. Consistent with ecosystem recovery following decades of intensive agriculture, the C and N content of the mineral soil increased under both the elevated CO 2 treatment and the ambient CO 2 control during the six-year period. This increase is attributed to accumulation of plant residues derived from fine roots with relatively high turnover rates rather than accumulation of refractory or physically protected soil organic matter (SOM). The elevated CO 2 treatment produced no detectable effect on the C and N content of the bulk mineral soils or of any particulate organic matter size fraction. Because the fumigation gas was strongly depleted in 13 C, the incorporation of new C could be traced within the ecosystem. Significant decreases in ␦ 13 C of soil organic carbon (SOC) under the elevated CO 2 treatment were used to estimate the mean residence times of intra-aggregate particulate organic matter and mineral-associated organic matter as well as the annual C inputs required to produce the observed changes in ␦ 13 C. Our results indicate that forest soils such as these will not significantly mitigate anthropogenic C inputs to the atmosphere. The organic matter pools receiving large annual C inputs have short mean residence times, while those with slow turnover rates receive small annual inputs.

Pine (Pinus strobus) sawdust was pyrolyzed in a fluidized-bed reactor between the temperatures of 400 and 600 °C. The fixed-bed volume and residence time were optimized to maximize the liquid yield. We report the detailed physical and chemical properties of the bio-oil fraction collected during fast pyrolysis. The liquid yield was maximized at 500 °C, whereas increased gas formation occurred at 600 °C. 13C NMR of the bio-oil fractions indicated a decrease in the carbohydrate fraction and an increase in the aromatic fraction when pyrolysis temperatures were increased from 500 to 600 °C. Over the ranges of our investigation, the effects of the fixed-bed volume and residence time were negligible on the chemical composition of the bio-oil. Toluene and ethyl acetate bio-oil extracts were analyzed by gas chromatography/mass spectrometry following chemical derivatization. At increased reaction temperatures, the process favored conversion of guaiacols to catechols.

The impact of anthropogenic CO2 emissions on climate change may be mitigated in part by C sequestration in terrestrial ecosystems as rising atmospheric CO2 concentrations stimulate primary productivity and ecosystem C storage. Carbon will be sequestered in forest soils if organic matter inputs to soil profiles increase without a matching increase in decomposition or leaching losses from the soil profile, or if the rate of decomposition decreases because of increased production of resistant humic substances or greater physical protection of organic matter in soil aggregates. To examine the response of a forest ecosystem to elevated atmospheric CO2 concentrations, the Duke Forest Free‐Air CO2 Enrichment (FACE) experiment in North Carolina, USA, has maintained atmospheric CO2 concentrations 200 μL L−1 above ambient in an aggrading loblolly pine (Pinus taeda) plantation over a 9‐year period (1996–2005). During the first 6 years of the experiment, forest‐floor C and N pools increased linearly under both elevated and ambient CO2 conditions, with significantly greater accumulations under the elevated CO2 treatment. Between the sixth and ninth year, forest‐floor organic matter accumulation stabilized and C and N pools appeared to reach their respective steady states. An additional C sink of ∼30 g C m−2 yr−1 was sequestered in the forest floor of the elevated CO2 treatment plots relative to the control plots maintained at ambient CO2 owing to increased litterfall and root turnover during the first 9 years of the study. Because we did not detect any significant elevated CO2 effects on the rate of decomposition or on the chemical composition of forest‐floor organic matter, this additional C sink was likely related to enhanced litterfall C inputs. We also failed to detect any statistically significant treatment effects on the C and N pools of surface and deep mineral soil horizons. However, a significant widening of the C : N ratio of soil organic matter (SOM) in the upper mineral soil under both elevated and ambient CO2 suggests that N is being transferred from soil to plants in this aggrading forest. A significant treatment × time interaction indicates that N is being transferred at a higher rate under elevated CO2 (P=0.037), suggesting that enhanced rates of SOM decomposition are increasing mineralization and uptake to provide the extra N required to support the observed increase in primary productivity under elevated CO2.