Founder effects and species introductions: A host versus parasite perspective

Species colonizations (both natural and anthropogenic) can be associated with genetic founder effects, where founding populations demonstrate significant genetic bottlenecks compared to native populations. Yet, many successfully established free�living species exhibit little reduction in genetic diversity—possibly due to multiple founding events and/or high propagule pressure during introductions. Less clear, however, is whether parasites may show differential signatures to their free�living hosts. Parasites with indirect life cycles may particularly be more prone to founder effects (i.e., more genetically depauperate) because of inherently smaller founding populations and complex life cycles. We investigated this question in native (east coast) and introduced (west coast) North American populations of a host snail Tritia obsoleta (formerly Ilyanassa obsoleta, the eastern mudsnail) and four trematode parasite species that obligately infect it. We examined genetic diversity, gene flow, and population structure using two molecular markers (mitochondrial and nuclear) for the host and the parasites. In the host snail, we found little to no evidence of genetic founder effects, while the trematode parasites showed significantly lower genetic diversity in the introduced versus native ranges. Moreover, the parasite's final host influenced infection prevalence and genetic diversity: Trematode species that utilized fish as final hosts demonstrated lower parasite diversity and heightened founder effects in the introduced range than those trematodes using birds as final hosts. In addition, inter�regional gene flow was strongest for comparisons that included the putative historical source region (mid�Atlantic populations of the US east coast). Overall, our results broaden understanding of the role that colonization events (including recent anthropogenic introductions) have on genetic diversity in non�native organisms by also evaluating less studied groups like parasites

Recommended Priorities for Research on Ecological Impacts of Ocean and Coastal Acidification in the U.S. Mid-Atlantic

The estuaries and continental shelf system of the United States Mid-Atlantic are subject to ocean acidification driven by atmospheric CO2, and coastal acidification caused by nearshore and land-sea interactions that include biological, chemical, and physical processes. These processes include freshwater and nutrient input from rivers and groundwater; tidally-driven outwelling of nutrients, inorganic carbon, alkalinity; high productivity and respiration; and hypoxia. Hence, these complex dynamic systems exhibit substantial daily, seasonal, and interannual variability that is not well captured by current acidification research on Mid-Atlantic organisms and ecosystems. We present recommendations for research priorities that target better understanding of the ecological impacts of acidification in the U. S. Mid-Atlantic region. Suggested priorities are: 1) Determining the impact of multiple stressors on our resource species as well as the magnitude of acidification; 2) Filling information gaps on major taxa and regionally important species in different life stages to improve understanding of their response to variable temporal scales and sources of acidification; 3) Improving experimental approaches to incorporate realistic environmental variability and gradients, include interactions with other environmental stressors, increase transferability to other systems or organisms, and evaluate community and ecosystem response; 4) Determining the capacity of important species to acclimate or adapt to changing ocean conditions; 5) Considering multi-disciplinary, ecosystem-level research that examines acidification impacts on biodiversity and biotic interactions; and 6) Connecting potential acidification-induced ecological impacts to ecosystem services and the economy. These recommendations, while developed for the Mid-Atlantic, can be applicable to other regions will help align research towards knowledge of potential larger-scale ecological and economic impacts

The Grizzly, September 26, 1980

Equipment Stolen From New Ritter Center • Conversion Eases Skyrocketing Utility Costs • Dean\u27s Office Discloses Frat GPAs • New Windows for NMD • New Spanish Lecturers Interviewed • IF, USGA to Sponsor Fall Picnic • Anderson Addresses College Crowd At Phila. Rally • College Invaded By World Of Technology • Draft Registration Closely Examined • Campus Grounds Receive Face Lift • Hamilton Presents Astronomy Discoveries • Try-outs for Trial by Jury • Weekends at Ursinus • Harriers Place 2nd At Lafayette Invitational • Grizzly Football Handled By W. Maryland • Sports Profile: Craig Walck • Field Hockey Finishes Week Undefeated • Strong Hitting By Bear V-Ball Outdoes Moravian • Offense Sputters As Bears Lose • Kreiger Powers Heathenshttps://digitalcommons.ursinus.edu/grizzlynews/1041/thumbnail.jp

The Grizzly, October 10, 1980

Alternative Housing Investigated • Unchanged since 1960: Activity Fee Increase Likely • Freshman Class Select Officers • Work Stalled On Campus Beautification • Bermans Give Sculpture To College • Ursinus News In Brief: Student chemistry group honored; Study skills workshop to be repeated; College appoints pol sci lecturer • Off-Campus Houses Rewired • Fast Method Discovered for Wismer • African Politics Subject of Oct. 15 Forum • IF Council, USGA Host Fall Picnic • Inactive Alarm System Questioned • Steranko Plays To Sparse Crowd • The Art of Procrastination • Toga! Toga! Toga! • New Ritter Center Dedicated • How To Get To Philly Without A Car • Guide To Ursinus Vocabulary • Science Fiction Books Discussion Offered • Lantern Needs Help • CLC Reveals Findings From Survey • Homecoming Candidates • Three Intramural Teams Clinch Playoff Spot • Booters Take Two • Hockey\u27s Unbeaten Streak Broken • X-Country Places 2nd At Mansfieldhttps://digitalcommons.ursinus.edu/grizzlynews/1043/thumbnail.jp

Establishment Failure in Biological Invasions: A Case History of Littorina littorea in California, USA

The early stages of biological invasions are rarely observed, but can provide significant insight into the invasion process as well as the influence vectors have on invasion success or failure.We characterized three newly discovered populations of an introduced gastropod, Littorina littorea (Linné, 1758), in California, USA, comparing them to potential source populations in native Europe and the North American East Coast, where the snail is also introduced. Demographic surveys were used to assess spatial distribution and sizes of the snail in San Francisco and Anaheim Bays, California. Mitochondrial DNA was sequenced and compared among these nascent populations, and various populations from the North American East Coast and Europe, to characterize the California populations and ascertain their likely source. Demographic and genetic data were considered together to deduce likely vectors for the California populations. We found that the three large California L. littorea populations contained only adult snails and had unexpectedly high genetic diversity rather than showing an extreme bottleneck as typically expected in recent introductions. Haplotype diversity in Californian populations was significantly reduced compared to European populations, but not compared to East Coast populations. Genetic analyses clearly suggested the East Coast as the source region for the California introductions.The California L. littorea populations were at an early, non-established phase of invasion with no evidence of recruitment. The live seafood trade is the most likely invasion vector for these populations, as it preferentially transports large numbers of adult L. littorea, matching the demographic structure of the introduced California L. littorea populations. Our results highlight continued operation of live seafood trade vectors and the influence of vectors on the demographic and genetic structure of the resulting populations, especially early stages of the invasion process

Observations of a Correlated Gamma-Ray and Optical Flare for BL Lacertae

The latest observations of BL Lacertae with the EGRET instrument on CGRO show that the gamma-ray flux was four times higher than the previous detection. Within the 1997 July 15-22 observation there was a dramatic factor of 2.5 increase in the gamma-ray flux, with a sharp peak of about 8 hours, and apparently preceding a brief optical flare by several hours. The gamma-ray photon spectral index was significantly harder than that for the previous detection.Comment: 11 pages, 3 figures. To be published in the Astrophysical Journal Letter

Lament as Transitional Justice

Works of human rights literature help to ground the formal rights system in an informal rights ethos. Writers have developed four major modes of human rights literature: protest, testimony, lament, and laughter. Through interpretations of poetry in Carolyn Forché’s anthology, Against Forgetting, and novels from Rwanda, the United States, and Bosnia, I focus on the mode of lament, the literature of mourning. Lament is a social and ritualized form, the purposes of which are congruent with the aims of transitional justice institutions. Both laments and truth commissions employ grieving narratives to help survivors of human rights trauma bequeath to the ghosts of the past the justice of a monument while renewing the survivors’ capacity for rebuilding civil society in the future. Human rights scholars need a broader, extra-juridical meaning for “transitional justice” if we hope to capture its power

Imprisonment and internment: Comparing penal facilities North and South

Recent references to the ‘warehouse prison’ in the United States and the prisión-depósito in Latin America seem to indicate that penal confinement in the western hemisphere has converged on a similar model. However, this article suggests otherwise. It contrasts penal facilities in North America and Latin America in terms of six interrelated aspects: regimentation; surveillance; isolation; supervision; accountability; and formalization. Quantitatively, control in North American penal facilities is assiduous (unceasing, persistent and intrusive), while in Latin America it is perfunctory (sporadic, indifferent and cursory). Qualitatively, North American penal facilities produce imprisonment (which enacts penal intervention through confinement), while in Latin America they produce internment (which enacts penal intervention through release). Closely entwined with this qualitative difference are distinct practices of judicial involvement in sentencing and penal supervision. Those practices, and the cultural and political factors that underpin them, represent an interesting starting point for the explanation of the contrasting nature of imprisonment and internment

Genomic epidemiology of a protracted hospital outbreak caused by multidrug-resistant Acinetobacter baumannii in Birmingham, England

BACKGROUND: Multidrug-resistant Acinetobacter baumannii commonly causes hospital outbreaks. However, within an outbreak, it can be difficult to identify the routes of cross-infection rapidly and accurately enough to inform infection control. Here, we describe a protracted hospital outbreak of multidrug-resistant A. baumannii, in which whole-genome sequencing (WGS) was used to obtain a high-resolution view of the relationships between isolates. METHODS: To delineate and investigate the outbreak, we attempted to genome-sequence 114 isolates that had been assigned to the A. baumannii complex by the Vitek2 system and obtained informative draft genome sequences from 102 of them. Genomes were mapped against an outbreak reference sequence to identify single nucleotide variants (SNVs). RESULTS: We found that the pulsotype 27 outbreak strain was distinct from all other genome-sequenced strains. Seventy-four isolates from 49 patients could be assigned to the pulsotype 27 outbreak on the basis of genomic similarity, while WGS allowed 18 isolates to be ruled out of the outbreak. Among the pulsotype 27 outbreak isolates, we identified 31 SNVs and seven major genotypic clusters. In two patients, we documented within-host diversity, including mixtures of unrelated strains and within-strain clouds of SNV diversity. By combining WGS and epidemiological data, we reconstructed potential transmission events that linked all but 10 of the patients and confirmed links between clinical and environmental isolates. Identification of a contaminated bed and a burns theatre as sources of transmission led to enhanced environmental decontamination procedures. CONCLUSIONS: WGS is now poised to make an impact on hospital infection prevention and control, delivering cost-effective identification of routes of infection within a clinically relevant timeframe and allowing infection control teams to track, and even prevent, the spread of drug-resistant hospital pathogens