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Protein arginine methyltransferases (PRMTs) make up a family of enzymes that transfer methyl groups onto arginine residues and play important roles in DNA repair, splicing, transcriptional control ...

Business process management software can help you to be faster, more adaptive, and more flexible in today's hypercompetitive environment. Like the warning lights on your car's dashboard, this software can help you spot problems before they cause disaster. The author explains how it works and how to shop for this kind of software. © 2005 Wiley Periodicals, Inc.

The growth, condition, and feed utilization patterns of juvenile southern bluefin tuna (SBT) fed moist-pellets were examined over a 19-wk period from March to July 1999. The SBT had significant weight gain over the course of the study, increasing on average from about 27 to 34 kg (dependent on size class). No significant weight gain by the SBT occurred in the first 5 wk of the study. Following this initial period of slow growth, the rate of weight gain increased, ranging between 40 to 90 g/d. Weight gain peaked after 11 wk, with no further gain occurring after this time point. Weight gain was strongly related to average daily feed intake (AFI) which was predominantly influenced by water temperature. Weight gain was minimal following the decrease of water temperatures below 15 C, consistent with a decrease in feed intake from peak values at the beginning of the study to basal levels by week 13. Basal feeding levels were maintained for the remainder of the study through to week 19. Although water temperature and AFI were strongly related, other time related effects also appeared to be signillcant. A relationship between condition index and feed intake was also identified. Condition index of the SBT increased from about 19 kg/m3 to 22 kg/m3 over the 19-wk period. Similar to the patterns observed in growth, there was also an initial delay in increases of condition index. The results from this study support that the majority of weight gain by juvenile SBT occurs during the early part of the production season and that this is most likely influenced indirectly through responses to water temperature. The results of this study also suggest that there is little value in conducting growth trials beyond the point where water temperatures decrease below 15 C. Although there was minimal weight gain or improvement in condition beyond the 11-wk time point, these parameters would need to be considered in conjunction with flesh quality characteristics to identify optimum harvesting regimes.

The immune system is designed to protect the host by distinguishing self-proteins from invading pathogens. However, neo-epitopes generated from self-proteins by post-translational modifications can trigger autoreactive immune cells to break such immune tolerance. One such modification, isoaspartyl (isoAsp), is believed to contribute the onset of autoimmune B and T cell responses and lupus pathology. Protein L-isoaspartyl (D-aspartyl) methyltransferase (PIMT) is the only known repair system for abnormal isoaspartyl residues. Previously, we found that the isoAsp content in lupus-prone MRL autoimmune mice increased and accumulated with age in brain and kidney, the major target organs in systemic lupus erythematosus (SLE). Recently, we found that the content of isoAsp modification in erythrocytes is correlated with PIMT activity in humans with SLE. The aberrant lupus T cell hyperproliferation can be rescued by PIMT overexpression. Of interest, ZAP70 is an essential kinase in T cell signaling and several ZAP70...

A 1,288 + 271-yr-old (1,350 ? 220 yr BP, radiocarbon age) seed of Sacred Lotus (Nelumbo nucifera Gaertn.) from an ancient lake bed at Pulantien, Liaoning Province, China, has been germinated and subsequently radiocarbon dated. This is the oldest demonstrably viable and directly dated seed ever reported, the preserved relict of one of the early crops of lotus cultivated by Buddhists at Pulantien after introduction of the religion into the region prior to 372 A.D. A small portion of the dry pericarp of a second lotus fruit from the same locale has been dated as being 332 + 135-yr-old (270 ? 60 yr BP, radiocarbon age) by accelerator mass spectroscopy at the Lawrence Livermore National Laboratory. This polycentenarian seed not only germinated but is still growing (since March, 1994). Of six old lotus fruits tested, two-thirds germinated, almost all in fewer than 4 d, as rapidly as fruits harvested from the progeny of Pulantien Sacred Lotus plants (under cultivation by the National Park Service in Washington, DC), and more rapidly than fresh fruits of Yellow Lotus [N. lutea (Willd.) Pers.]. Growth of the old lotus is robust: rhizome formation and leaf emergence at rhizome nodes are more rapid than those of the Pulantien progeny, although the leaf width is smaller. Activity of the protein-repair enzyme L-isoaspartyl methyltransferase in the old lotus seed is persistent during germination and is as robust as that in the progeny, and the degree of aspartyl racemization in proteins of the two groups of plants is minimal and essentially identical. The six dated ancient Sacred Lotus fruits range in age from 95 to 1,288 yr (with a mean age of 595 ? 380 yr), evidently reflecting their production, deposition, and preservation at varying times during the intervening millennium.

We have investigated the spontaneous degradation of aspartate and asparagine residues via succinimide intermediates in model peptides in organic co-solvents. We find that the rate of deamidation at asparagine residues is markedly reduced in solvents of low dielectric strength. Theoretical considerations suggest that this decrease in rate is due to the destabilization of the deprotonated peptide bond nitrogen anion that is the postulated attacking species in succinimide formation. This result suggests that asparagine residues in regions with low dielectric constants, such as the interior of a protein or in a membrane bilayer, are protected from this type of degradation reaction. On the other hand, we found little or no effect on the rate of succinimide-mediated isomerization of aspartate residues when subjected to the same changes in dielectric constant. In this case, the destabilization of the attacking peptide bond nitrogen anion may be balanced by increased protonation of the aspartyl side chain carboxyl group, a reaction that results in a superior leaving group. Consequently, any protein structure or conformation that would increase the protonation of an aspartate side chain carboxyl group can be expected to render that residue more labile. These results may help explain why particular aspartate residues have been found to degrade in proteins at rates comparable to those of asparagine residues, even though aspartyl-containing peptides degrade more slowly than corresponding asparaginyl-containing peptides in aqueous solutions.

Aspartic acid and asparagine residues racemize rapidly relative to other amino acid residues in proteins and peptides. This has been attributed to the increased acidity of the α-carbons of succinimide residues derived from the spontaneous cyclizations of these residues. To understand the basis of this effect, the acidities of model compounds were calculated using ab initio quantum mechanics (RHF/6-31+G*). The results were also checked with DFT (Becke3LYP/6-31+G*) and solvent cavity models (IPCM and SCIPCM). The geometries of succinimide, 2-pyrrolidinone, and the derived enolate anions were optimized, and the gas phase deprotonation energies were calculated. The imide is more acidic than the amide by 18 kcal/mol in the gas phase. Since there is a qualitative correlation between gas phase and aqueous acidities, this result provides an explanation for the experimental observations that the rate of peptidyl succinimide racemization can be ∼105 times greater than that of unmodified aspartic acid residues. To q...