Characterization and Quantification of Highly Sulfated Glycosaminoglycan Isomers by Gated-Trapped Ion Mobility Spectrometry Negative Electron Transfer Dissociation MS/MS

Glycosaminoglycans (GAGs) Play Vital Roles in Many Biological Processes and Are Naturally Present as Complex Mixtures of Polysaccharides with Tremendous Structural Heterogeneity, Including Many Structural Isomers. Mass Spectrometric Analysis of GAG Isomers, in Particular Highly Sulfated Heparin (Hep) and Heparan Sulfate (HS), is Challenging Because of their Structural Similarity and Facile Sulfo Losses during Analysis. Herein, We Show that Highly Sulfated Hep/HS Isomers May Be Resolved by Gated-Trapped Ion Mobility Spectrometry (Gated-TIMS) with Negligible Sulfo Losses. Subsequent Negative Electron Transfer Dissociation (NETD) Tandem Mass Spectrometry (MS/MS) Analysis of TIMS-Separated Hep/HS Isomers Generated Extensive Glycosidic and Cross-Ring Fragments for Confident Isomer Differentiation and Structure Elucidation. the High Mobility Resolution and Preservation of Labile Sulfo Modifications Afforded by Gated-TIMS MS Analysis Also Allowed Relative Quantification of Highly Sulfated Heparin Isomers. These Results Show that the Gated-TIMS-NETD MS/MS Approach is Useful for Both Qualitative and Quantitative Analysis of Highly Sulfated Hep/HS Compounds in a Manner Not Possible with Other Techniques

HST Observations of the Host Galaxies of BL Lacertae Objects

Six BL Lac objects from the complete 1 Jy radio-selected sample of 34 objects were observed in Cycle 5 with the HST WFPC2 camera to an equivalent limiting flux of mu_I~26 mag/arcsec^2. Here we report results for the second half of this sample, as well as new results for the first three objects, discussed previously by Falomo et al. (1997). In addition, we have analyzed in the same way HST images of three X-ray-selected BL Lacs observed by Jannuzi et al. (1997). The ensemble of 9 BL Lac objects spans the redshift range from z=0.19 to ~1. Host galaxies are clearly detected in seven cases, while the other two, at z~0.258 (redshift highly uncertain) and z=0.997, are not resolved. The HST images constitute a homogeneous data set with unprecedented morphological information between a few tenths of an arcsecond and several arcseconds from the nucleus, allowing us in 6 of the 7 detected host galaxies to rule out definitively a pure disk light profile. The host galaxies are luminous ellipticals with an average absolute magnitude of M_I~-24.6 mag (with dispersion 0.7 mag), more than a magnitude brighter than L* and comparable to brightest cluster galaxies. The morphologies are generally smooth and have small ellipticities (epsilon<0.2). Given such roundness, there is no obvious alignment with the more linear radio structures. In the six cases for which we have HST WFPC2 images in two filters, the derived color profiles show no strong spatial gradients and are as expected for K-corrected passively evolving elliptical galaxies. The host galaxies of the radio-selected and X-ray-selected BL Lacs for this very limited sample are comparable in both morphology and luminosity.Comment: 23 pages, including 6 postscript figures and 3 tables (embedded). Latex requires aaspp4.sty and psfig.sty (not included). Accepted for publication in the Astrophysical Journa

Segregate or cooperate- a study of the interaction between two species of Dictyostelium

<p>Abstract</p> <p>Background</p> <p>A major challenge for evolutionary biology is explaining altruism, particularly when it involves death of one party and occurs across species. Chimeric fruiting bodies of <it>Dictyostelium discoideum </it>and <it>Dictyostelium purpureum </it>develop from formerly independent amoebae, and some die to help others. Here we examine co-aggregation between <it>D. discoideum </it>and <it>D. purpureum</it>, determine its frequency and which party benefits, and the extent of fair play in contribution to the altruistic caste.</p> <p>Results</p> <p>We mixed cells from both species in equal proportions, and then we analyzed 198 individual fruiting bodies, which always had either a <it>D. discoideum </it>or <it>D. purpureum </it>phenotype (<it>D. discoideum</it>- 98, <it>D. purpureum</it>- 100). Fifty percent of the fruiting bodies that looked like <it>D. discoideum </it>and 22% of the fruiting bodies that looked like <it>D. purpureum </it>were chimeric, though the majority of spores in any given fruiting body belonged to one species (<it>D. discoideum </it>fruiting bodies- 0.85 ± 0.03, <it>D. purpureum </it>fruiting bodies- 0.94 ± 0.02). Clearly, there is species level recognition occurring that keeps the cells mostly separate. The number of fruiting bodies produced with the <it>D. discoideum </it>phenotype increased from 225 ± 32 fruiting bodies when <it>D. discoideum </it>was alone to 486 ± 61 in the mix treatments. However, the number of <it>D. discoideum </it>spores decreased, although not significantly, from 2.75e⁷± 1.29e⁷spores in the controls to 2.06e⁷± 8.33e⁶spores in the mix treatments. <it>D. purpureum </it>fruiting body and spore production decreased from 719 ± 111 fruiting bodies and 5.81e⁷± 1.26e⁷spores in the controls to 394 ± 111 fruiting bodies and 9.75e⁶± 2.25e⁶spores in the mix treatments.</p> <p>Conclusion</p> <p>Both species appear to favor clonality but can cooperate with each other to produce fruiting bodies. Cooperating amoebae are able to make larger fruiting bodies, which are advantageous for migration and dispersal, but both species here suffer a cost in producing fewer spores per fruiting body.</p

A 180 Kpc Tidal Tail in the Luminous Infrared Merger Arp 299

We present VLA HI observations and UH88 deep optical B- and R-band observations of the IR luminous merger Arp 299 (= NGC 3690 + IC 694). These data reveal a gas-rich, optically faint tidal tail with a length of over 180 kpc. The size of this tidal feature necessitates an old interaction age for the merger (~750 Myr since first periapse), which is currently experiencing a very young star burst (~20 Myr). The observations reveal a most remarkable structure within the tidal tail: it appears to be composed of two parallel filaments separated by ~20 kpc. One of the filaments is gas rich with little if any starlight, while the other is gas poor. We believe that this bifurcation results from a warped disk in one of the progenitors. The quantities and kinematics of the tidal HI suggest that Arp 299 results from the collision of a retrograde Sab-Sb galaxy (IC 694) and a prograde Sbc-Sc galaxy (NGC 3690) that occurred 750 Myr ago and which will merge into a single object in ~60 Myr. We suggest that the present IR luminous phase in this system is due in part to the retrograde spin of IC 694. Finally, we discuss the apparent lack of tidal dwarf galaxies within the tail.Comment: LaTex, 14 pages, 11 figures, 4 tables, uses emulateapj.sty. Accepted to AJ for July 1999. For version with full-resolution images see http://www.cv.nrao.edu/~jhibbard/a299/HIpaper/a299HI.htm

Modeling the role of the close- range effect and environmental variables in the occurrence and spread of Phragmites australis in four sites on the Finnish coast of the Gulf of Finland and the Archipelago Sea

Peer reviewe

Seasonal Spatial Segregation in Blue Sharks (Prionace glauca) by Sex and Size Class in the Northeast Pacific Ocean

Aim: Animal tracking can provide unique insights into the ecology and conservation of marine species, such as the partitioning of habitat, including differences between life history stages or sexes, and can inform fisheries stock assessments, bycatch reduction and spatial management such as dynamic management. Location: Northeast Pacific Ocean. Methods: We used satellite tracking data from 47 blue sharks (Prionace glauca) from the Northeast Pacific to determine movements and home range along the west coast of North America, and sex–size class (immature females, mature males) specific habitat preferences using boosted regression trees. Using a suite of static and dynamic environmental variables, we determined distribution and habitat preferences across summer and fall for each sex–size class. Results: We found that there was spatial segregation between sex–size classes particularly in the summer months with immature females found largely north of 33°N, and males south of 35°N. In fall, females travelled south, resulting in an overlap in distributions south of 37°N. Sea surface temperature (SST), latitude and longitude were top predictors. However, immature females and adult males demonstrated unique habitat preferences including SST, with immature females preferring cooler temperatures (SST \u3c 15°C) than adult males in summer, and a broader band of SST than adult males in fall. All models performed well, explaining 50%–67% of deviance, and 23%–41% of deviance when predictions were cross‐validated. Main conclusions: We provide first insights into coastal movements and habitat preferences of blue sharks in the Northeast Pacific. We found that immature females undergo a seasonal southward migration in this more coastal habitat, similar to patterns observed in the North Atlantic. We also found some overlap between adult males and immature females in fall months, suggesting the importance of more coastal habitat in managing this species, particularly in determining population structure for blue shark stock assessments, and reducing blue shark bycatch