Using community science to identify predators of spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae), in North America.

Spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae), is an invasive insect that was first detected in the United States in 2014 and feeds on a wide variety of plants, with economic impacts on the agricultural, ornamental, and timber industries. Part of what likely contributes to the success of L. delicatula in its invaded range is that it appears to be chemically defended by sequestering toxins from its host plant(s), which may deter predators in the introduced range. To determine the identity and behavior of North American predators that feed on spotted lanternfly, we performed a community science study in which we asked members of the public to contribute reports of animals feeding on spotted lanternfly through a Facebook page. The largest group of reported predators was arthropods followed by birds. Araneae was the arthropod order with the most reports and Phasianidae was the most frequently reported bird family. Using Pearson's χ2 tests, we also identified significant relationships between predator behavior and (1) taxonomic group of the predator, (2) L. delicatula life stage, and (3) host plant L. delicatula was observed on. These results can help to guide future research on predator host shifting to spotted lanternfly and potential for biocontrol as a management tactic.

Thermodynamic analysis of cooperative ligand binding by the ATP-binding DNA aptamer indicates a population-shift binding mechanism.

The ATP-binding DNA aptamer is often used as a model system for developing new aptamer-based biosensor methods. This aptamer follows a structure-switching binding mechanism and is unusual in that it binds two copies of its ligand. We have used isothermal titration calorimetry methods to study the binding of ATP, ADP, AMP and adenosine to the ATP-binding aptamer. Using both individual and global fitting methods, we show that this aptamer follows a positive cooperative binding mechanism. We have determined the binding affinity and thermodynamics for both ligand-binding sites. By separating the ligand-binding sites by an additional four base pairs, we engineered a variant of this aptamer that binds two adenosine ligands in an independent manner. Together with NMR and thermal stability experiments, these data indicate that the ATP-binding DNA aptamer follows a population-shift binding mechanism that is the source of the positive binding cooperativity by the aptamer.

Dispersal of Lycorma delicatula (Hemiptera: Fulgoridae) Nymphs Through Contiguous, Deciduous Forest.

Spotted lanternfly (Lycorma delicatula) is a recently introduced pest in the United States, where it threatens the wine, timber, and ornamentals industries. Knowledge of the dispersal ability of L. delicatula is key to developing effective management strategies for this invasive pest. We conducted a mark, release, re-sight study, marking nymphs with fluorescent powders and observing dispersal distances from a central release point at three time points over 7 d following release. To examine how dispersal patterns changed over the course of nymphal development, we repeated this process for each of L. delicatula's four instars. All releases were conducted in contiguous, deciduous forest, which is a widespread habitat type within L. delicatula's invaded range and a habitat where this pest may have negative ecological and economic impacts. We found that nymphs displayed clear directionality in their movement following release, apparently preferring to move uphill on the modest 6° grade at our release site. Most nymphs remained near the release location, while some moved tens of meters. The maximum displacement we observed was 65 m from the release point, 10 d after release. Nymphs were re-sighted singly and in small groups on a variety of trees, shrubs, and understory vegetation. All four instars had similar dispersal distances over time, though third instar nymphs moved farthest on average, with estimated median displacement of 16.9 m 7 d after release. Further studies are needed to provide additional information on what factors influence spotted lanternfly dispersal.

Behavioral and Physiological Resistance to Desiccation in Spotted Wing Drosophila (Diptera: Drosophilidae).

With a high surface to volume ratio, small organisms must carefully regulate their internal water status. Spotted-wing drosophila, Drosophila suzukii (Matsumura), is an invasive frugivorous insect distributed across a wide range of geographical regions that can have periods of dry and hot weather, suggesting that this species has strategies to avoid stressful environments and reduce water loss. It also survives winter as an adult fly, indicating that it has adaptations to the low air humidity of this season. To determine the importance of water stress to D. suzukii, we studied their survival in environments of low humidity, which was manipulated using Drierite, and their survival and water loss in response to desiccation. Survival of both sexes was lower in drier conditions, and while female winter morph D. suzukii had higher mortality early on, remaining flies were able to survive longer in the drier conditions than the summer morphs. A bioassay method was adapted from Enjin et al. (2016) using 48-well plates to videotape the location of flies and quantify their behavioral responses to humidity. Male and female D. suzukii avoided dry conditions within the bioassay system, but only when there was at least 25% differential between humidity extremes. This response was observed for both summer and winter morphs of D. suzukii and our results provide guidance for attempts to manipulate crop environments to reduce the economic impact of this pest.

Medical student reflections on geriatrics: Moral distress, empathy, ethics and end of life.

Medical students' early clinical encounters may influence their perceptions of geriatrics. This study examines reflective essays written by 3rd-year medical students on required clinical rotations. Using content analysis, the authors analyzed the essays' thematic content. The authors then used chi-squared analysis to compare themes with geriatric patients (age 60+) to themes with other age groups. One hundred twenty out of 802 essays described a geriatric patient. The most common geriatric themes were (1) death and dying, (2) decision making, (3) meaningful physician-patient interactions, (4) quality of care, and (5) professional development. Geriatric essays were more likely to discuss death/dying and risk-benefit themes and less likely to discuss abuse. Geriatric essays were more likely to describe students' moral distress. Geriatric essays with moral distress were more likely to include empathy themes compared to geriatric essays without moral distress. Geriatric patients may pose unique ethical challenges for early clinical students.

The three-dimensional structure of the Moorella thermoacetica selenocysteine insertion sequence RNA hairpin and its interaction with the elongation factor SelB.

Incorporation of the amino acid selenocysteine into a growing protein chain involves the interaction between a hairpin in the mRNA termed the selenocysteine insertion sequence (SECIS) and the special elongation factor SelB. Here we present the structure of the SECIS from the thermophilic organism Moorella thermoacetica (SECIS-MT) determined using nuclear magnetic resonance (NMR) spectroscopy. The SECIS-MT hairpin structure contains a pentaloop with the first and fourth nucleotides of the loop forming a noncanonical GC base pair; the fifth loop nucleotide is bulged out and unstructured. The G and U in positions two and three are on opposite sides of the loop and solvent exposed. The backbone resonances of the SECIS-binding domain from the M. thermoacetica SelB protein were assigned, and the degree of chemical shift perturbations that occur upon SECIS binding were mapped onto the structure of the complex. We demonstrate that a region in the third winged-helix domain of SelB, not previously implicated in binding, is affected by SECIS binding.

Oxidative strand scission of nucleic acids by a multinuclear copper(II) complex.

The compound [Cu(2)(II)(D(1))(H(2)O)(2)](ClO(4))(4).2H(2)O [D(1)=binucleating ligand with tris(2-pyridylmethyl)amine (TMPA) moieties linked in the 5-pyridyl position by a -CH(2)CH(2)- bridge] mediated efficient oxidative cleavage of pBR322 plasmid DNA under reducing conditions. A mononuclear analogue, [Cu(TMPA)(H(2)O)](ClO(4))(2), was less effective at linearizing supercoiled (Form I) plasmid DNA as compared to the binuclear complex. A new method for quenching the copper-dependent reactions has been developed to avoid plasmid scission by the binuclear complex and the standard gel loading buffer. EDTA was not sufficient for retarding copper reaction, but diethyldithiocarbamic acid was capable of inhibiting all reactivity. Investigation of oxidative cleavage of double-helical oligonucleotides by [Cu(2)(II)(D(1))(H(2)O)(2)](ClO(4))(4) confirmed the enhanced reactivity of the binuclear over the mononuclear complex and provided mechanistic insights into the nature of the reaction. Cleavage of DNA required both the binuclear complex and a reductant and likely proceeded through an O(2)-derived intermediate that does not include a diffusible hydroxyl radical. The greater efficiency of the binuclear complex relative to the mononuclear analogue is consistent with their relative abilities to activate dioxygen.

Irofulven induces apoptosis in breast cancer cells regardless of caspase-3 status.

Caspase-3 deficiency can limit the efficiency of pro-apoptotic anticancer treatments. Irofulven (hydroxymethylacyl-fulvene, HMAF. MGI 114, NSC 683863) is an antitumor drug, currently in a Phase III and multiple Phase II trials, which can differentiate between tumor and normal cells in apoptosis induction. This study investigated whether apoptosis induced by irofulven requires caspase-3. Irofulven action was compared in breast cancer cells differing in caspase-3 status: deficient MCF-7 cells and proficient MDA-MB-231 cells and in normal human mammary epithelial cells, HMEC. Irofulven induces significant, concentration and time-dependent apoptotic DNA fragmentation in breast cancer cell lines, regardless of caspase-3 status. After 12, 24 and 48 h incubation at 1 microM irofulven (approximately 3 x GI50), fragmented DNA comprised 3.7, 14.1 and 34.6% and 8.4, 12.6 and 20.3% of total DNA in MCF-7 and MDA-MB-231 cells, respectively. Cell viability (trypan blue exclusion) remained largely unaffected during the first 24 h but decreased markedly after 48 h, indicating secondary necrosis. Net losses in cell numbers were apparent at 48 h. Normal HMEC cells were refractory to 1 microM drug with only approximately 3-9% fragmented DNA after 12-48 h, although apoptosis was observed at drug levels >3 microM. The broad-spectrum caspase inhibitor Z-VAD-fmk inhibited irofulven-induced apoptosis of all cell lines at 20 microM with nearly complete abrogation of apoptosis at 100 microM. Irofulven treatment resulted in marginal caspase-3 processing in MDA-MB-231 and HMEC cells. These results indicate that whereas the caspase cascade mediates irofulven- induced apoptosis, caspase-3 is dispensable (supported by NIH CA70091 and CA78706).