DopEcR is required for the 30-minute courtship memory induced by 1-hour courtship conditioning.

<p>(A) Thirty-minute courtship memory in wild-type flies (control) and flies heterozygous (<i>DopEcR^PB1</i>/+), homozygous (<i>DopEcR^PB1</i>/<i>DopEcR^PB1</i>), and hemizygous (<i>DopEcR^PB1</i>/Df(3L)ED4341) for <i>DopEcR</i>. <i>DopEcR^PB1</i> homozygotes and hemizygotes were defective for 30-minute courtship memory. (B) Time course of courtship memory in <i>DopEcR^PB1</i> homozygotes. Significant memory was observed immediately after conditioning, but not 15 or 30 minutes after conditioning. (C) A defect in 30-minute courtship memory in flies that ubiquitously express the <i>DopEcR</i> RNAi after eclosion, in response to RU486 stimulation of the <i>tub</i>-GS-Gal4 driver. The presence or absence of courtship memory was evaluated by applying the Mann–Whitney U-test to naïve and conditioned males. Statistical significance is shown above each bar as NS, no significant difference, **, <i>P</i><0.01 or ***, <i>P</i><0.001. Sample numbers for naïve and conditioned flies are shown under each graph. PIs were analyzed using Krustal-Wallis One-Way ANOVA, followed by Dunn's pairwise test for multiple comparisons. #, <i>P</i><0.05; ##, <i>P</i><0.01. Error bars (s.e.m.).</p

A Novel Role for Ecdysone in <i>Drosophila</i> Conditioned Behavior: Linking GPCR-Mediated Non-canonical Steroid Action to cAMP Signaling in the Adult Brain

<div><p>The biological actions of steroid hormones are mediated primarily by their cognate nuclear receptors, which serve as steroid-dependent transcription factors. However, steroids can also execute their functions by modulating intracellular signaling cascades rapidly and independently of transcriptional regulation. Despite the potential significance of such “non-genomic” steroid actions, their biological roles and the underlying molecular mechanisms are not well understood, particularly with regard to their effects on behavioral regulation. The major steroid hormone in the fruit fly <i>Drosophila</i> is 20-hydroxy-ecdysone (20E), which plays a variety of pivotal roles during development via the nuclear ecdysone receptors. Here we report that DopEcR, a G-protein coupled receptor for ecdysteroids, is involved in activity- and experience-dependent plasticity of the adult central nervous system. Remarkably, a courtship memory defect in <i>rutabaga</i> (Ca²⁺/calmodulin-responsive adenylate cyclase) mutants was rescued by <i>DopEcR</i> overexpression or acute 20E feeding, whereas a memory defect in <i>dunce</i> (cAMP-specific phosphodiestrase) mutants was counteracted when a loss-of-function <i>DopEcR</i> mutation was introduced. A memory defect caused by suppressing dopamine synthesis was also restored through enhanced DopEcR-mediated ecdysone signaling, and rescue and phenocopy experiments revealed that the mushroom body (MB)—a brain region central to learning and memory in <i>Drosophila</i>—is critical for the DopEcR-dependent processing of courtship memory. Consistent with this finding, acute 20E feeding induced a rapid, DopEcR-dependent increase in cAMP levels in the MB. Our multidisciplinary approach demonstrates that DopEcR mediates the non-canonical actions of 20E and rapidly modulates adult conditioned behavior through cAMP signaling, which is universally important for neural plasticity. This study provides novel insights into non-genomic actions of steroids, and opens a new avenue for genetic investigation into an underappreciated mechanism critical to behavioral control by steroids.</p></div

Modeling Photosensitized Secondary Organic Aerosol Formation in Laboratory and Ambient Aerosols

Photosensitized reactions involving imidazole-2-carboxaldehyde (IC) have been experimentally observed to contribute to secondary organic aerosol (SOA) growth. However, the extent of photosensitized reactions in ambient aerosols remains poorly understood and unaccounted for in atmospheric models. Here we use GAMMA 4.0, a photochemical box model that couples gas-phase and aqueous-phase aerosol chemistry, along with recent laboratory measurements of the kinetics of IC photochemistry, to analyze IC-photosensitized SOA formation in laboratory and ambient settings. Analysis of the laboratory results of Aregahegn et al. (2013) suggests that photosensitized production of SOA from limonene, isoprene, α-pinene, β-pinene, and toluene by ³IC* occurs at or near the surface of the aerosol particle. Reactive uptake coefficients were derived from the experimental data using GAMMA 4.0. Simulations of aqueous aerosol SOA formation at remote ambient conditions including IC photosensitizer chemistry indicate less than 0.3% contribution to SOA growth from direct reactions of ³IC* with limonene, isoprene, α-pinene, β-pinene, and toluene, and an enhancement of less than 0.04% of SOA formation from other precursors due to the formation of radicals in the bulk aerosol aqueous phase. Other, more abundant photosensitizer species, such as humic-like substances (HULIS), may contribute more significantly to aqueous aerosol SOA production

The mushroom body is critical for the DopEcR-dependent processing of courtship memory.

<p>(A) Rescue of the <i>DopEcR^PB1</i> memory defect by expression of wild-type <i>DopEcR</i> transgene using the <i>DopEcR</i>-Gal4 driver. (B) Rescue of <i>DopEcR^PB1</i> memory defect by expression of wild-type <i>DopEcR</i> transgene under control of the MB-specific c772, c739 and 201 y drivers. Note that MB-Gal4 lines drive reporter expression in different subsets of MB neurons (see text). (C) Courtship memory defect induced by MB-specific expression of the <i>DopEcR</i> RNAi using the c772 and c739 drivers. The presence or absence of courtship memory was evaluated by applying Mann–Whitney U-test to naïve and conditioned flies. Statistical significance is shown above each bar. NS, no significant difference. **, <i>P</i><0.01; ***, <i>P</i><0.001. Sample numbers for naïve and conditioned flies are shown under each graph. PIs were analyzed using Student's t-test or Krustal-Wallis One-Way ANOVA, followed by Dunn's pairwise test for multiple comparisons. #, <i>P</i><0.05; ###, <i>P</i><0.001. Error bars (s.e.m.).</p

<i>DopEcR</i> loss-of-function mutants show slow habituation of the giant-fiber escape circuit.

<p>(A) Schematic representation of the giant-fiber (GF) pathway. GF afferent neurons (aff.). Tergotrochanteral muscle (TTM), TTM motor neuron (TTMn), dorsal longitudinal muscle (DLM), peripherally synapsing interneuron (PSI), and DLM motor neuron (DLMn). (B) The long-latency threshold (LLT), short-latency threshold (SLT) and refractory period (RP) for <i>DopEcR</i> mutants and wild-type flies. The data are presented as box plots. (C) Representative traces of muscle responses to 5-Hz brain stimulation. Vertical bars and dots denote successful and failed responses, respectively. An arrowhead represents the time at which a gentle air puff was applied to trigger dishabituation, which confirms that the failure to respond is due to habituation. (D) Cumulative muscle responses to 5-Hz brain stimulations. (E) The average numbers of 5-Hz stimuli delivered before the fly experiences five consecutive failures (criteria for habituation). Crosses with arrows represent flies that did not show habituation within the observation period (2 minutes). Error bars (s.e.m). Data were analyzed by Krustal-Wallis One-Way ANOVA, followed by Dunn's pairwise test for multiple comparisons. NS, no significant difference. *, <i>P</i><0.05.</p

A <i>DopEcR</i> hypomorphic allele and the <i>DopEcR</i>-Gal4 expression pattern.

<p>(A) Schematic representation of the <i>Drosophila DopEcR</i> gene. <i>DopEcR</i> contains 5 exons and spans a 12.7 kb genomic region in the 64B2-64B3 cytological interval (Flybase). The <i>DopEcR</i> exons are represented by boxes, and the coding regions are indicated with purple color. A green arrow indicates the direction of transcription of <i>DopEcR</i>. The <i>DopEcR</i> locus is completely uncovered by deficiency Df(3L)ED4341. The PBac(PB)c02142 (<i>DopEcR^PB1</i>) allele harbors an insertion of the <i>piggyBac</i> transposable element within the second intron. The insertion site is indicated as a red arrow with an inverted triangle. (B) <i>DopEcR</i> transcript levels in <i>DopEcR^PB1</i> homozygotes and trans-heterozygotes, as assessed by RT-PCR analysis. (C–G) Expression of the GFP reporter gene (UAS-CD4-tdGFP <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003843#pgen.1003843-Han2" target="_blank">[70]</a>) driven by <i>DopEcR</i>-Gal4 (green) and synaptic neuropil labeled with the nc82 antibody against presynaptic marker protein Bruchpilot (magenta). Anterior view of the adult brain displaying <i>DopEcR</i>-Gal4 expression pattern (C) and the nc82 staining (E). A merged image is shown in (D). (F) Adult brain with the thoracicoabdominal ganglion (ventral view). (G) Dorsal view of the thoracicoabdominal ganglion. Scale bars represent 100 µm. ABD: abdominal ganglion; AL: antennal lobe; AMMC: antennal mechanosensory and motor center; MB: mushroom body; OL: optic lobe; SEG: subesophageal ganglion; T1: prothoracic ganglion; T2: metathoracic ganglion; T3: mesothoracic ganglion; VLP: ventrolateral protocerebrum; wing: wing neuropil.</p

Impaired ecdysone synthesis causes a courtship memory defect.

<p>(A) Rescue of courtship memory in <i>DTS-3</i> males by feeding flies 20E prior to conditioning. (B) A defect in 30-minute courtship memory when the <i>dib</i> RNAi was expressed ubiquitously in adults, in response to RU486 application (<i>tub5</i>-GS-Gal4 driver). The <i>dib</i> RNAi-induced memory defect was not observed when flies were fed 20E, but was observed when 20E feeding was accompanied by the expression of the <i>DopEcR</i> RNAi. (C) Rescue of courtship memory in 3-iodo tyrosine (3-IY)-treated males by feeding flies 20E prior to conditioning. (D) Courtship memory in 3-IY-treated males was not restored by 20E when the <i>DopEcR</i> RNAi was expressed ubiquitously in adults. For 20E and RU486 feeding experiments, control flies received vehicle. The presence or absence of courtship memory was evaluated by applying the Mann–Whitney U-test to naïve and conditioned flies. Statistical significance is shown above each bar. NS, no significant difference. **, <i>P</i><0.01; ***, <i>P</i><0.001. Sample numbers for naïve and conditioned flies are shown under each graph. PIs were analyzed using Student's t-test or Krustal-Wallis One-Way ANOVA. #, <i>P</i><0.05. Error bars (s.e.m.).</p

Diatoms in wastewater treatment: Potentials, applications, and values of biomass

Diatoms have unique silica cellular and metabolic characteristics and can grow in various environments, including wastewater, facilitating pollutant removal. Diatoms provide a sustainable solution to municipal wastewater treatment, particularly in the tertiary and quaternary stages, contributing to carbon neutrality. Diatom-based materials (such as diatom biomass) have wide applications and can be processed into value-added bioproducts such as lipids, polysaccharides, and pigments. Despite their potentials, the applications of diatoms in wastewater treatment are limited. Existing reviews fail to address how diatom growth kinetics affects wastewater treatment. Here, we for the first time summarize diatom growth kinetics and propose promising species for municipal wastewater treatment. Given the scarcity of reviews on diatom performance in wastewater treatment, we also discuss the efficacy of diatoms in removing contaminants from municipal wastewater. Moreover, we elucidate the removal mechanisms of nutrients, heavy metals, and emerging contaminants by diatoms that are missing in existing reviews. Considering the complexity of wastewater, we emphasize selecting diatom species with high growth rates, tolerance to contaminants, efficient nutrient removal/uptake, and COD removal, and bioproduct yields. This will ensure both effective treatment and economic viability. In addition, we discuss the value of diatom frustules and bioproducts generated from wastewater. Lastly, we highlight future directions including promoting diatom growth, exploring diatom-dominated consortia in wastewater treatment, and evaluating the values of diatom biomass cultivated in wastewater. This review examines the potential and applications of diatoms in municipal wastewater treatment, especially effluent polishing. Diatoms are a sustainable solution to municipal wastewater treatmentDiatoms can remove nutrients, heavy metals, and emerging pollutants from wastewaterSummarized the growth kinetics of various diatom species for the first timeDiscussed the removal mechanisms of contaminants from wastewater by diatomsCompiled the wide applications of diatom biomass from wastewater Diatoms are a sustainable solution to municipal wastewater treatment Diatoms can remove nutrients, heavy metals, and emerging pollutants from wastewater Summarized the growth kinetics of various diatom species for the first time Discussed the removal mechanisms of contaminants from wastewater by diatoms Compiled the wide applications of diatom biomass from wastewater</p

Development of Two-Dimensional Electronic-Vibrational Sum Frequency Generation (2D-EVSFG) for Vibronic and Solvent Couplings of Molecules at Interfaces and Surfaces

Many photoinduced excited states’ relaxation processes and chemical reactions occur at interfaces and surfaces, including charge transfer, energy transfer, proton transfer, proton-coupled electron transfer, configurational dynamics, conical intersections, etc. Of them, interactions of electronic and vibrational motions, namely, vibronic couplings, are the main determining factors for the relaxation processes or reaction pathways. However, time-resolved electronic-vibrational spectroscopy for interfaces and surfaces is lacking. Here we develop interface/surface-specific two-dimensional electronic-vibrational sum frequency generation spectroscopy (2D-EVSFG) for time-dependent vibronic coupling of excited states at interfaces and surfaces. We further demonstrate the fourth-order technique by investigating vibronic coupling, solvent correlation, and time evolution of the coupling for photoexcited interface-active molecules, crystal violet (CV), at the air/water interface as an example. The two vibronic absorption peaks for CV molecules at the interface from the 2D-EVSFG experiments were found to be more prominent than their counterparts in bulk from 2D-EV. Quantitative analysis of the vibronic peaks in 2D-EVSFG suggested that a non-Condon process participates in the photoexcitation of CV at the interface. We further reveal vibrational solvent coupling for the zeroth level on the electronic state with respect to that on the ground state, which is directly related to the magnitude of its change in solvent reorganization energy. The change in the solvent reorganization energy at the interface is much smaller than that in bulk methanol. Time-dependent center line slopes (CLSs) of 2D-EVSFG also showed that kinetic behaviors of CV at the air/water interface are significantly different from those in bulk methanol. Our ultrafast 2D-EVSFG experiments not only offer vibrational information on both excited states and the ground state as compared with the traditional doubly resonant sum frequency generation and electronic-vibrational coupling but also provide vibronic coupling, dynamical solvent effects, and time evolution of vibronic coupling at interfaces

Observation of Organic Molecules at the Aerosol Surface

Organic molecules at the gas-particle interface of atmospheric aerosols influence the heterogeneous chemistry of the aerosol and impact climate properties. The ability to probe the molecules at the aerosol particle surface in situ therefore is important but has been proven challenging. We report the first successful observations of molecules at the surface of laboratory-generated aerosols suspended in air using the surface-sensitive technique second harmonic light scattering (SHS). As a demonstration, we detect trans-4-[4-(dibutylamino)­styryl]-1-methylpyridinium iodide and determine its population and adsorption free energy at the surface of submicron aerosol particles. This work illustrates a new and versatile experimental approach for studying how aerosol composition may affect the atmospheric properties