Evaluation of Visible Implant Elastomer Tags in Wild Coastal Cutthroat Trout in the Marine Environment

We evaluated the detectability of visible implant elastomer (VIE) tags in Coastal Cutthroat TroutOncorynchus clarkii clarkiiin the marine environment by comparing visually identified recaptures from VIE tags with known recaptures that were identified through genotype matching. A total of 89 individual Coastal Cutthroat Trout were marked in the lower jaw with colored VIE tags, sampled for genetics, and recaptured across 12 months in 2015. The rate of correspondence between the VIE tags and genetic matches was 92% (82/89) of the recaptured Coastal Cutthroat Trout in the nearshore marine environment. We found that red- and blue-colored VIE tags were detected at a higher rate (100%) than were yellow- and orange-colored tags (87.3% and 90.6%, respectively). In contrast, tag type (single or double), tag location (left or right), fish length (FL, mm), and time (days) since tagging had no effect on tag detectability during the study period. All of the tag colors were recovered for the maximum life of the study (up to 342 days). In all of the cases of nondetections (5/89), the tags were not identified upon initial recapture or subsequent capture events, suggesting that they were lost or not visible immediately upon insertion in the field-as opposed to being unidentified due to the degradation of tag detectability over time. The results of this study suggest that VIE tags have the potential to be detectable in juvenile and adult Coastal Cutthroat Trout for at least 12 months after insertion, with blue and red performing the best. Additional monitoring extending beyond 12 months after tagging would be necessary to identify the maximum life of VIE tags

Thermal Stability of the Human Immunodeficiency Virus Type 1 (HIV-1) Receptors, CD4 and CXCR4, Reconstituted in Proteoliposomes

BACKGROUND: The entry of human immunodeficiency virus (HIV-1) into host cells involves the interaction of the viral exterior envelope glycoprotein, gp120, and receptors on the target cell. The HIV-1 receptors are CD4 and one of two chemokine receptors, CCR5 or CXCR4. METHODOLOGY/PRINCIPAL FINDINGS: We created proteoliposomes that contain CD4, the primary HIV-1 receptor, and one of the coreceptors, CXCR4. Antibodies against CD4 and CXCR4 specifically bound the proteoliposomes. CXCL12, the natural ligand for CXCR4, and the small-molecule CXCR4 antagonist, AMD3100, bound the proteoliposomes with affinities close to those associated with the binding of these molecules to cells expressing CXCR4 and CD4. The HIV-1 gp120 exterior envelope glycoprotein bound tightly to proteoliposomes expressing only CD4 and, in the presence of soluble CD4, bound weakly to proteoliposomes expressing only CXCR4. The thermal stability of CD4 and CXCR4 inserted into liposomes was examined. Thermal denaturation of CXCR4 followed second-order kinetics, with an activation energy (E(a)) of 269 kJ/mol (64.3 kcal/mol) and an inactivation temperature (T(i)) of 56°C. Thermal inactivation of CD4 exhibited a reaction order of 1.3, an E(a) of 278 kJ/mol (66.5 kcal/mol), and a T(i) of 52.2°C. The second-order denaturation kinetics of CXCR4 is unusual among G protein-coupled receptors, and may result from dimeric interactions between CXCR4 molecules. CONCLUSIONS/SIGNIFICANCE: Our studies with proteoliposomes containing the native HIV-1 receptors allowed an examination of the binding of biologically important ligands and revealed the higher-order denaturation kinetics of these receptors. CD4/CXCR4-proteoliposomes may be useful for the study of virus-target cell interactions and for the identification of inhibitors

Effective monitoring of freshwater fish

Freshwater ecosystems constitute only a small fraction of the planet’s water resources, yet support much of its diversity, with freshwater fish accounting for more species than birds, mammals, amphibians, or reptiles. Fresh waters are, however, particularly vulnerable to anthropogenic impacts, including habitat loss, climate and land use change, nutrient enrichment, and biological invasions. This environmental degradation, combined with unprecedented rates of biodiversity change, highlights the importance of robust and replicable programmes to monitor freshwater fish assemblages. Such monitoring programmes can have diverse aims, including confirming the presence of a single species (e.g. early detection of alien species), tracking changes in the abundance of threatened species, or documenting long-term temporal changes in entire communities. Irrespective of their motivation, monitoring programmes are only fit for purpose if they have clearly articulated aims and collect data that can meet those aims. This review, therefore, highlights the importance of identifying the key aims in monitoring programmes, and outlines the different methods of sampling freshwater fish that can be used to meet these aims. We emphasise that investigators must address issues around sampling design, statistical power, species’ detectability, taxonomy, and ethics in their monitoring programmes. Additionally, programmes must ensure that high-quality monitoring data are properly curated and deposited in repositories that will endure. Through fostering improved practice in freshwater fish monitoring, this review aims to help programmes improve understanding of the processes that shape the Earth's freshwater ecosystems, and help protect these systems in face of rapid environmental change