Oust the louse: leaping behaviour removes sea lice from wild juvenile sockeye salmon Oncorhynchus nerka

We conducted a manipulative field experiment to determine whether the leaping behaviour of wild juvenile sockeye salmon Oncorhynchus nerka dislodges ectoparasitic sea lice Caligus clemensi and Lepeophtheirus salmonis by comparing sea‐lice abundances between O. nerka juveniles prevented from leaping and juveniles allowed to leap at a natural frequency. Juvenile O. nerka allowed to leap had consistently fewer sea lice after the experiment than fish that were prevented from leaping. Combined with past research, these results imply potential costs due to parasitism and indicate that the leaping behaviour of juvenile O. nerka does, in fact, dislodge sea lice.     

Structure and Evolution of the Adh Genes of Drosophila Mojavensis

The nucleotide sequence of the Adh region of Drosophila mojavensis has been completed and the region found to contain a pseudogene, Adh-2 and Adh-1 arranged in that order. Comparison of the sequence divergence of these genes to one another and to the Adh region of Drosophila mulleri and other species has allowed the development of a model for the evolution of the duplication of the Adh genes. There have been two major events. An initial duplication of an Adh gene whose dual promoter structure was similar to Drosophila melanogaster, resulted in a species with two Adh genes, one of which may have had only a proximal promoter. A second duplication of this gene generated an Adh region containing three genes. It is proposed that one of these is the ancestral gene having dual promoters, while the other two possess only proximal promoters. Subsequent events have resulted in both a change in the regulation of Adh-2 such that it is expressed as if it had a "distal" type promoter and the mutational inactivation of the most upstream gene resulting in the creation of a pseudogene. The sequence of the D. mojavensis Adh region has also revealed the presence of an element which is composed of juxtaposed inverted imperfectly repeated elements. There is a surprising and not fully explainable strong similarity of the nucleotide sequence of the 5' flanking region of the pseudogene in D. mojavensis and D. mulleri.     

Parathyroid hormone and prostaglandin E2 stimulate both inositol phosphates and cyclic AMP accumulation in mouse osteoblast cultures.

Parathyroid hormone (PTH) and prostaglandin E2 (PGE2) are physiological agonists which stimulate bone cells to resorb bone, a process by which the mineralized extracellular bone matrix is dissolved. Bone resorption has a key role in the maintenance of plasma calcium levels. It has been established that both PTH and PGE2 activate adenylate cyclase in osteoblasts, but it is apparent that (1) the two agents have qualitatively different effects on osteoblasts, and (2) the generation of cyclic AMP cannot account for all the effects of PTH on bone cell metabolism. Others have demonstrated that PTH and PGE2 may also elevate intracellular calcium levels, but the mechanism by which this is achieved has not been fully defined. Here we have investigated the effects of PTH on neonatal mouse osteoblasts in culture and shown that physiological concentrations of the hormone (50 nM) caused a small increase (22%) in total inositol phosphates accumulation, with a larger increase (40%) in inositol trisphosphate. We found that this activation occurred at lower concentration than was necessary to activate adenylate cyclase. PGE2 was a more effective activator of inositol phosphates accumulation than PTH, causing up to 300% increase in the total inositol phosphates after 30 min. Both PTH and PGE2 stimulated cyclic AMP accumulation, but the activation of adenylate cyclase by forskolin did not enhance inositol phosphates production. We conclude that both PTH and PGE2 stimulate phosphoinositide turnover in mouse osteoblasts and suggest that this mechanism may contribute to their elevation of intracellular calcium in bone cells.     

Induction of early breeding in red deer (Cervus elaphus) by melatonin

Lactating (N = 12) and non-lactating (N = 6) red deer hinds and one stag at pasture were given concentrates (500 g/head) containing melatonin (5 mg/head) daily at 16:00 h from 18 June to 16 October. The stag shed the antler velvet and started rutting 5 weeks ahead of untreated stags, and hinds had their first oestrus and ovulation of the breeding season in mid-September, 5 weeks in advance of control lactating (N = 9) and non-lactating (N = 5) hinds. Treated hinds were allowed to mate with the treated stag and control hinds ran in an adjacent paddock with an untreated stag. All hinds became pregnant during the study with all but 2 melatonin-fed hinds (1 lactating, 1 non-lactating) and 1 control hind (lactating) conceiving at the first oestrus. Melatonin-treated hinds lost slightly more live weight than did controls from June to November, but their suckled calves grew throughout at a rate similar to those of control hinds.     

Glycoprotein synthesis in yeast. Identification of Man8GlcNAc2 as an essential intermediate in oligosaccharide processing

Synthesis of the N-linked oligosaccharides of Saccharomyces cerevisiae glycoproteins has been studied in vivo by labeling with [2-3H]mannose and gel filtration analysis of the products released by endoglycosidase H. Both small oligosaccharides, Man8-14GlcNAc, and larger products, Man greater than 20GlcNAc, were labeled. The kinetics of continuous and pulse-chase labeling demonstrated that Glc3Man9GlcNAc2, the initial product transferred to protein, was rapidly (t1/2 congruent to 3 min) trimmed to Man8GlcNAc2 and then more slowly (t1/2 = 10-20 min) elongated to larger oligosaccharides. No oligosaccharides smaller than Man8GlcNAc2 were evident with either labeling procedure. In confirmation of the trimming reaction observed in vivo, 3H-labeled Man9-N-acetylglucosaminitol from bovine thyroglobulin and [14C]Man9GlcNAc2 from yeast oligosaccharide-lipid were converted in vitro by broken yeast cells to 3H-labeled Man8-N-acetylglucosaminitol and [14C]Man8GlcNAc2. Man8GlcNAc and Man9GlcNAc from yeast invertase and from bovine thyroglobulin were purified by gel filtration and examined by high field 1H-NMR analysis. Invertase Man8GlcNAc (B) and Man9GlcNAc (C) were homogeneous compounds, which differed from the Man9GlcNAc (A) of thyroglobulin by the absence of a specific terminal alpha 1,2-linked mannose residue. The Man9GlcNAc of invertase (C) had an additional terminal alpha 1,6-linked mannose and appeared identical in structure with that isolated from yeast containing the mnn1 and mnn2 mutations (Cohen, R. E., Zhang, W.-j., and Ballou, C. E. (1982) J. Biol. Chem. 257, 5730-5737). It is concluded that Man8GlcNAc2, formed by removal of glucose and a single mannose from Glc3Man9GlcNAc2, is the ultimate product of trimming and the minimal precursor for elongation of the oligosaccharides on yeast glycoproteins. The results suggest that removal of a particular terminal alpha 1,2-linked mannose from Man9GlcNAc2 by a highly specific alpha-mannosidase exposes the nascent Man-alpha 1,6-Man backbone for elongation with additional alpha 1,6-linked mannose residues, according to the following scheme: (formula, see text).     

Functional consequences of the proteolytic removal of regulatory serines from the nonhelical tailpiece of Acanthamoeba myosin II

The actin-activated Mg2(+)-ATPase activity of myosin II from Acanthamoeba castellanii is regulated by phosphorylation of 3 serines in its 29-residue, nonhelical, COOH-terminal tailpiece, i.e., serines-1489, -1494, and -1499 or, in reverse order, residues 11, 16, and 21 from the COOH terminus. To investigate the essential requirements for regulation, myosin II filaments in the presence of F-actin were digested by arginine-specific submaxillary gland protease. Two-dimensional peptide mapping of purified, cleaved myosin II showed that the two most terminal phosphorylation sites, serines-1494 and -1499, had been removed. Cleaved dephosphorylated myosin II retained full actin-activated Mg2(+)-ATPase activity (with no change in Vmax or Kapp) and the ability to form filaments similar to those of the native enzyme. However, higher Mg2+ concentrations were required for both filament formation and maximal ATPase activity. The one remaining regulatory serine in the cleaved myosin II was phosphorylatable by myosin II heavy-chain kinase, and phosphorylation inactivated the actin-activated Mg2(+)-ATPase activity, as in the case of the native myosin II. Also as in the case of the native myosin II, phosphorylated cleaved myosin II inhibited the actin-activated Mg2(+)-ATPase activity of dephosphorylated cleaved myosin II when the two were copolymerized. These results suggest that at least 18 of the 29 residues in the nonhelical tailpiece of the heavy chain are not required for either actin-activated Mg2(+)-ATPase activity or filament formation and that phosphorylation of Ser-1489 is sufficient to regulate the actin-activated Mg2(+)-ATPase activity of myosin II.     

Response of nucleoside diphosphate kinase to the adenylate energy charge

The reaction catalyzed by nucleoside diphosphate kinase responds to the energy charge of the adenylate pool. The velocity is maximal at a charge of 1.0, and decreases sharply with a decrease in the charge. This response may control the flow of phosphate from ATP into the other nucleotide pools and thus participate in the regulation of macromolecular synthesis by the energy level of the cell, as reflected in the charge of the adenylate pool.     

Predictive Modelling to Identify Near-Shore,Fine-Scale Seabird Distributions during the Breeding Season

During the breeding season seabirds are constrained to coastal areas and are restricted in their movements, spending much of their time in near-shore waters either loafing or foraging. However, in using these areas they may be threatened by anthropogenic activities such as fishing, watersports and coastal developments including marine renewable energy installations. Although many studies describe large scale interactions between seabirds and the environment, the drivers behind near-shore, fine-scale distributions are not well understood. For example, Alderney is an important breeding ground for many species of seabird and has a diversity of human uses of the marine environment, thus providing an ideal location to investigate the near-shore fine-scale interactions between seabirds and the environment. We used vantage point observations of seabird distribution, collected during the 2013 breeding season in order to identify and quantify some of the environmental variables affecting the near-shore, fine-scale distribution of seabirds in Alderney’s coastal waters. We validate the models with observation data collected in 2014 and show that water depth, distance to the intertidal zone, and distance to the nearest seabird nest are key predictors in the distribution of Alderney’s seabirds. AUC values for each species suggest that these models perform well, although the model for shags performed better than those for auks and gulls. While further unexplained underlying localised variation in the environmental conditions will undoubtedly effect the fine-scale distribution of seabirds in near-shore waters we demonstrate the potential of this approach in marine planning and decision making.     

A soluble single-chain T-cell receptor IL-2 fusion protein retains MHC-restricted peptide specificity and IL-2 bioactivity

Antibody-based targeted immunotherapy has shown promise as an approach to treat cancer. However, many known tumor-associated antigens are not expressed as integral membrane proteins and cannot be utilized as targets for antibody-based therapeutics. In order to expand the limited target range of antibodies, we have constructed a soluble single-chain T-cell receptor (TCR) fusion protein designated 264scTCR/IL-2. This fusion protein is comprised of a three-domain HLA-A2-restricted TCR specific for a peptide epitope of the human p53 tumor suppressor protein, which is overexpressed in a broad range of human malignancies. The 264scTCR/IL-2 fusion protein has been expressed at high levels in mammalian cells, and milligram quantities have been purified. MHC-restricted antigen-specific binding properties are maintained in the single-chain, three-domain TCR portion of the fusion protein, and the IL-2 portion retains bioactivity similar to that of free recombinant IL-2. Moreover, this fusion protein is capable of conjugating target and effector cells, remains intact in the blood and substantially increases the half life of the IL-2 portion of the molecule. Finally, the 264scTCR/IL-2 fusion protein can be used to stain tumor cells and is capable of reducing lung metastases in an experimental model of metastasis. Thus, TCR-based fusion proteins may provide a novel class of targeted immunotherapeutics for cancer.