Seasonal home ranges and fidelity to breeding sites among ringed seals

Population structure and patterns of habitat use among ringed seals (Phoca hispida) are poorly known, in part because seasonal movements have not been adequately documented. We monitored the movements of 98 ringed seals in the Beaufort and Chukchi seas between 1990 and 2006 using three forms of telemetry. In the winter—spring period (when the seals were occupying shorefast ice), we used radio and ultra-sonic tags to track movements above and below the ice, respectively. We used satellite-linked transmitters in summer and fall (when the seals ranged away from their winter sites) to track at-sea movements. In the shorefast ice habitat, the home ranges of 27 adult males ranged from <1 to 13.9 km² (median = 0.628) while the home ranges of 28 adult females ranged from <1 to 27.9 km² (median = 0.652). The 3-dimensional volumes used by 9 seals tracked acoustically under the ice averaged 0.07 (SD = 0.04) km³ for subadults and adult males and 0.13 (SD = 0.04) km³ for adult females. Three of the radio-tracked seals and 9 tracked by satellite ranged up to 1,800 km from their winter/spring home ranges in summer but returned to the same small (1–2 km²) sites during the ice-bound months in the following year. The restricted movements of ringed seals during the ice-bound season—including the breeding season—limits their foraging activities for most of the year and may minimize gene flow within the species.     

Improving the comparative map of porcine chromosome 9 with respect to human chromosomes 1, 7 and 11

Conserved segments have been identified by ZOO-FISH between pig chromosome 9 (SSC9) and human chromosomes 1, 7 and 11. To assist in the identification of positional candidate genes for QTL on SSC9, the comparative map was further developed. Primers were designed from porcine EST sequence homologous to genes in regions of human chromosomes 1, 7 and 11. Porcine ESTs were then physically assigned using the INRA somatic cell hybrid panel (INRASCHP) and the high-resolution radiation hybrid panel (IMpRH). Seventeen genes (PEPP3, RAB7L1, FNBP2, MAPKAPK2, GNAI1, ABCB1, STEAP, AKAP9, CYP51A1, SGCE, ROBO4, SIAT4C, GLUL, CACNA1E, PTGS2, C1orf16 and ETS1) were mapped to SSC9, while GUSB, CPSF4 and THG-1 were assigned to SSC3.     

APT102, a novel adpase, cooperates with aspirin to disrupt bone metastasis in mice

Platelets contribute to the development of metastasis, the most common cause of mortality in cancer patients, but the precise role that anti-platelet drugs play in cancer treatment is not defined. Metastatic tumor cells can produce platelet alphaIIb beta3 activators, such as ADP and thromboxane A(2) (TXA(2)). Inhibitors of platelet beta3 integrins decrease bone metastases in mice but are associated with significant bleeding. We examined the role of a novel soluble apyrase/ADPase, APT102, and an inhibitor of TXA(2) synthesis, acetylsalicylic acid (aspirin or ASA), in mouse models of experimental bone metastases. We found that treatment with ASA and APT102 in combination (ASA + APT102), but not either drug alone, significantly decreased breast cancer and melanoma bone metastases in mice with fewer bleeding complications than observed with alphaIIb beta3 inhibition. ASA + APT102 diminished tumor cell induced platelet aggregation but did not directly alter tumor cell viability. Notably, APT102 + ASA treatment did not affect initial tumor cell distribution and similar results were observed in beta3-/- mice. These results show that treatment with ASA + APT102 decreases bone metastases without significant bleeding complications. Anti-platelet drugs such as ASA + APT102 could be valuable experimental tools for studying the role of platelet activation in metastasis as well as a therapeutic option for the prevention of bone metastases.     

Purification of the blue-green pigment “marennine” from the marine tychopelagic diatom Haslea ostrearia (Gaillon/Bory) Simonsen

The diatom Haslea ostrearia that lives in oyster ponds has the distinctive feature of synthesizing “marennine”, a blue-green pigment of which the chemical nature still remains unknown. This pigment is responsible for the greening of oyster gills. Here, we report a new method for extraction and purification of intracellular (accumulated in the apex of the cell) and extracellular (released into the external medium) forms of the pigment. Intracellular marennine is obtained by extraction from blue algal pellets with a carbonate buffer. The extract is then centrifuged and filtered. Extracellular marennine is obtained by clarification of blue-coloured culture medium. Both extracts are then purified by a semi-preparative process, using ultrafiltration through membranes and anion-exchange chromatography. This procedure allows us to produce native pigment displaying the degree of purity required to enter upon the molecular characterisation of marennine. By this process, about 35% of the initial amount of pigment can be recovered. If necessary, this method could be easily scaled up to a larger production system to accommodate potential industrial applications.     

Feeding damage by Diuraphis noxia results in a nutritionally enhanced phloem diet

The feeding behavior of Diuraphis noxia Mordvilko (Homoptera: Aphididae) on susceptible hosts causes both ultrastructural and tissue level damage which may affect phloem composition. Genetic evidence suggests that endosymbiotic bacteria in most aphids overproduce limiting amino acids to benefit hosts but that D. noxia depends less on endosymbionts for these nutrients, possibly due to an enriched diet. To determine whether D. noxia feeding damage results in higher concentrations of essential amino acids, stylet exudates were analyzed from wheat (Triticum aestivum) damaged to different degrees. Comparison of samples from undamaged and damaged susceptible wheat revealed changes in amino acid composition and an increase in levels of essential amino acids, indicating a nutritionally enhanced ingesta. The changes in stylet exudates paralleled changes in leaf exudates, indicating that the effects are systemic. Feeding damage is not observed on a resistant wheat host, var. Halt, and leaf exudates from infested Halt did not show changes in amino acid composition. Mean relative growth of nymphs was significantly lower on Halt than on susceptible Arapahoe, indicating that Halt is a less suitable host. Both varieties show similar amino acid levels in non-infested samples, suggesting that D. noxia infestation does not enhance the phloem environment in Halt. This study provides evidence that aphid feeding can generate a nutritionally enhanced phloem diet.     

Production and characterization of a compound inhibitory to Vibrio parahaemolyticus from Proteus vulgaris

The production and characteristics of a compound in Proteus vulgaris G cultures which was capable of inhibiting Vibrio parahaemolyticus and other food-borne pathogens was investigated. Production was influenced by medium composition, pH and temperature but not by the extent of aeration. The compound was most inhibitory at the optimum temperature for growth of V. parahaemolyticus. The inhibitor was most stable at pH 7·0 and inhibition occurred even after heating at 70°C for 30 min and after autoclaving. Ultrafiltration showed that the inhibitor had a molecular weight less than 1000. Thin layer chromatography of filtrates and subsequent peptidase digestion indicated that it was at least in part a peptide. The inhibitor purified by Sephadex G-15 gel filtration had a calculated molecular weight of 731 and contained only six amino acids.     

The common src homology region 2 domain of cytoplasmic signaling proteins is a positive effector of v-fps tyrosine kinase function.

A conserved noncatalytic domain SH2 (for src homology region 2) is located immediately N terminal to the kinase domains of all cytoplasmic protein-tyrosine kinases. We found that the wild-type v-fps SH2 domain stimulated the enzymatic activity of the adjacent kinase domain 10-fold and functioned as a powerful positive effector of catalytic and transforming activities within the v-fps oncoprotein (P130gag-fps). Partial proteolysis of P130gag-fps and supporting genetic data indicated that the v-fps SH2 domain exerts its effect on catalytic activity through an intramolecular interaction with the kinase domain. Amino acid alterations in the SH2 domain that impaired kinase function interfered with association of the SH2 domain with the kinase domain. Deletion of a conserved octapeptide motif converted the v-fps SH2 domain from an activator to an inhibitor of tyrosine kinase activity. This latent inhibitory activity of v-fps SH2 has functional implications for phospholipase C-gamma and p21ras GTPase-activating protein, both of which have two distinct SH2 domains suggestive of complex regulation. In addition to regulating the specific activity of the kinase domain, the SH2 domain of P130gag-fps was also found to be required for the tyrosine phosphorylation of specific cellular proteins, notably polypeptides of 124 and 62 kilodaltons. The SH2 domain therefore appears to play a dual role in regulation of kinase activity and recognition of cellular substrates.