Temperature-dependent Fashion Research Articles

Evaluation of organophosphorus pesticide tyrosine adducts for postmortem change by human serum albumin with liquid chromatography quadrupole Orbitrap mass spectrometry.

Organophosphorus pesticides (OPPs) having a phosphate ester moiety, such as malathion (MA) and methidathion (DMTP), are widely used and have been detected in many fatal cases of accidental exposure or suicide in Japan. In forensic toxicology, the accurate determination of blood OPP concentration is mandatory to prove death by OPP poisoning. However, fatal pesticide concentration in blood at autopsy varies depending on the circumstances surrounding the dead body. In this study, we found that 16 OPPs were degraded by human serum albumin (HSA) in a temperature-dependent fashion. The mechanism underlying MA, DMTP, azinphos-methyl, etrimfos, fenthion (MPP), pirimiphos-methyl, (E)-dimethylvinphos, (Z)-dimethylvinphos, vamidothion, edifenphos (EDDP), fosthiazate, and pyraclofos degradation involves the formation of adducts with tyrosine residues in HSA. The mass spectra obtained by liquid chromatography quadrupole Orbitrap mass spectrometry revealed that phosphate ester amino acid adducts such as Y-adduct1, Y-adduct2, Y-adduct3, Y-adduct4, and Y-adduct5 were formed in HSA solution incubated with OPPs. These results indicate that the 16 OPPs are postmortem changed by HSA. The detection of phosphate ester amino acid adducts such as Y-adduct1, Y-adduct2, Y-adduct3, Y-adduct4, and Y-adduct5, instead of MA, DMTP, azinphos-methyl, etrimfos, MPP, pirimiphos-methyl, (E)-dimethylvinphos, (Z)-dimethylvinphos, vamidothion, EDDP, fosthiazate, and pyraclofos per se, may be used to determine death by these OPPs poisoning.

Identification of post-mortem paliperidone metabolite in human blood by LC-Q-Orbitrap-MS.

Paliperidone is a widely used antipsychotic agent detected in many fatal intoxications and suicide cases. In forensic toxicology, the accurate determination of blood paliperidone concentrations is required to prove death by paliperidone poisoning. However, the lethal concentration of paliperidone in blood at autopsy differs from that at the time of death. In this study, we found that paliperidone was decomposed by hemoglobin (Hb) through the Fenton reaction in a temperature-dependent fashion. The mechanism underlying paliperidone decomposition involves the cleavage of its C-N bond linker moiety. The mass spectra obtained by liquid chromatography quadrupole orbitrap mass spectrometry (LC-Q-Orbitrap-MS) revealed the formation of 6-fluoro-3-(4-piperidinyl)benzisoxazole (PM1) in Hb/H2O2 solution incubated with paliperidone, as well as in the blood of individuals who died from intentional ingestion of paliperidone. These results suggest that PM1 is the only metabolite produced from paliperidone as a result of temperature-dependent, post-mortem changes induced by Hb via the Fenton reaction, and may be useful as a biomarker to correct for the concentration of paliperidone in blood at the time of death in clinical cases.

Neuronal overexpression of hTDP-43 in Caenorhabditis elegans impairs motor function.

Transactive response DNA binding-protein 43 (TDP-43) is a conserved RNA/DNA-binding protein with a role in RNA metabolism and homeostasis. Aberrant TDP-43 functioning has been considered a major culprit in amyotrophic lateral sclerosis (ALS). Caenorhabditis elegans can be used to phenocopy ALS in vivo . Since disrupted locomotion is a strong readout of toxicity, we examined multiple motor phenotypes of a C. elegans model expressing human wild-type TDP-43 ( hTDP-43 ) pan-neuronally. Our data reveal that impaired locomotion includes more than the common deficits in crawling capacity and the presence of early-onset paralysis. We show that reduced thrashing, abnormal coiling, and decreased pharyngeal pumping are also observed, in a temperature-dependent fashion.

Evaluation of Post-Mortem Interaction between Hemoglobin and Oxime-Type Carbamate Pesticides.

Oxime-type carbamate pesticides having an oxime moiety such as aldicarb, butocarboxim, methomyl, oxamyl, and thiofanox are widely used and have been detected in many fatal cases of accidental exposure or suicide. In forensic toxicology, the accurate determination of blood pesticide concentration is obligatory to prove death by oxime-type carbamate pesticide poisoning. However, the fatal pesticide concentration in blood at autopsy differs from that at the time of death. In this study, we found that oxime-type carbamate pesticides were decomposed by Hb in a temperature-dependent fashion. The mechanism underlying methomyl, aldicarb, oxamyl, and thiofanox decomposition involves the formation of adducts with the amino acids in Hb. With regard to butocarboxim, its decomposition involves the oxidation of the free form and the formation of adducts with the amino acids in Hb. The mass spectra obtained by liquid chromatography quadrupole time-of-flight mass spectrometry revealed that carbamylated amino acid adducts such as Wcar-adduct and Vcar-adduct were formed in Hb solution incubated with methomyl, aldicarb, oxamyl, and thiofanox, whereas alkylated amino acid adducts such as Walkyl-adduct were formed in Hb solution incubated with butocarboxim. These results indicate that aldicarb, butocarboxim, methomyl, oxamyl, and thiofanox are post-mortem changed by Hb.

Endosymbionts moderate constrained sex allocation in a haplodiploid thrips species in a temperature-sensitive way

Maternally inherited bacterial endosymbionts that affect host fitness are common in nature. Some endosymbionts colonise host populations by reproductive manipulations (such as cytoplasmic incompatibility; CI) that increase the reproductive fitness of infected over uninfected females. Theory predicts that CI-inducing endosymbionts in haplodiploid hosts may also influence sex allocation, including in compatible crosses, however, empirical evidence for this is scarce. We examined the role of two common CI-inducing endosymbionts, Cardinium and Wolbachia, in the sex allocation of Pezothrips kellyanus, a haplodiploid thrips species with a split sex ratio. In this species, irrespective of infection status, some mated females are constrained to produce extremely male-biased broods, whereas other females produce extremely female-biased broods. We analysed brood sex ratio of females mated with males of the same infection status at two temperatures. We found that at 20 °C the frequency of constrained sex allocation in coinfected pairs was reduced by 27% when compared to uninfected pairs. However, at 25 °C the constrained sex allocation frequency increased and became similar between coinfected and uninfected pairs, resulting in more male-biased population sex ratios at the higher temperature. This temperature-dependent pattern occurred without changes in endosymbiont densities and compatibility. Our findings indicate that endosymbionts affect sex ratios of haplodiploid hosts beyond the commonly recognised reproductive manipulations by causing female-biased sex allocation in a temperature-dependent fashion. This may contribute to a higher transmission efficiency of CI-inducing endosymbionts and is consistent with previous models that predict that CI by itself is less efficient in driving endosymbiont invasions in haplodiploid hosts.

Pomacea canaliculata Ampullar Proteome: A Nematode-Based Bio-Pesticide Induces Changes in Metabolic and Stress-Related Pathways.

Simple SummaryPomacea canaliculata is a South American invasive freshwater snail, affecting biodiversity, crop production and public health, now retrieved in Asian, North American and European countries. The identification of molecules connected to P. canaliculata adaptability may prove helpful in developing strategies that could overcome the snail’s resilience and stop its spread in non-original countries. This research presents the changes occurring in the proteome of a small organ, i.e., the ampulla, after challenging the snails with a nematode-based bio-pesticide. Transmission electron microscopy (TEM) analysis demonstrated that this organ has a complex connective ultrastructure and contains rhogocytes. TEM also confirmed the ampulla as a deposit of nitrogen-based material. After exposure to the nematode-based bio-pesticide, significant changes were observed for enzymes mainly involved in antioxidant defence, energy metabolism and cytoskeletal dynamics. These changes recall the systemic oxidative stress response that the snails undergo during the arousal after aestivation/hibernation, a physiological response involving other organs that, similarly to the ampulla, store nitrogen-based compounds. As fundamental players of the response against bio-pesticides and environmental cues, the enzymes identified in this research and involved in stress-related pathways may represent a suitable target for the efficacious and sustainable control of P. canaliculata spread.Pomacea canaliculata is a freshwater gastropod known for being both a highly invasive species and one of the possible intermediate hosts of the mammalian parasite Angiostrongylus cantonensis. With the aim of providing new information concerning P. canaliculata biology and adaptability, the first proteome of the ampulla, i.e., a small organ associated with the circulatory system and known as a reservoir of nitrogen-containing compounds, was obtained. The ampullar proteome was derived from ampullae of control snails or after exposure to a nematode-based molluscicide, known for killing snails in a dose- and temperature-dependent fashion. Proteome analysis revealed that the composition of connective ampulla walls, cell metabolism and oxidative stress response were affected by the bio-pesticide. Ultrastructural investigations have highlighted the presence of rhogocytes within the ampullar walls, as it has been reported for other organs containing nitrogen storage tissue. Collected data suggested that the ampulla may belong to a network of organs involved in controlling and facing oxidative stress in different situations. The response against the nematode-based molluscicide recalled the response set up during early arousal after aestivation and hibernation, thus encouraging the hypothesis that metabolic pathways and antioxidant defences promoting amphibiousness could also prove useful in facing other challenges stimulating an oxidative stress response, e.g., immune challenges or biocide exposure. Targeting the oxidative stress resistance of P. canaliculata may prove helpful for increasing its susceptibility to bio-pesticides and may help the sustainable control of this pest’s diffusion.

Unsteady stagnation-point flow of upper-convected Oldroyd-B nanofluid with variable thermal conductivity and relaxation-retardation double-diffusion model

Purpose This paper aims to examine the unsteady stagnation-point flow, heat and mass transfer of upper-convected Oldroyd-B nanofluid along a stretching sheet. The thermal conductivity is taken in a temperature-dependent fashion. With the aid of Cattaneo–Christov double-diffusion theory, relaxation-retardation double-diffusion model is advanced, which considers not only the effect of relaxation time but also the influence of retardation time. Convective heat transfer is not ignored. Additionally, experiments verify that with sodium carboxymethylcellulose (CMC) solutions as base fluid, not only the flow curve conforms to Oldroyd-B model but also thermal conductivity decreases linearly with the increase of temperature. Design/methodology/approach The suitable pseudo similarity transformations are adopted to address partial differential equations to ordinary differential equations, which are computed analytically through homotopy analysis method (HAM). Findings It is worth noting that the increase of stagnation-point parameter diminishes momentum loss, so that the velocity enlarges, which makes boundary layer thickness thinner. With the increase of thermal retardation time parameter, the nanofluid temperature rises that implies heat penetration depth boosts up and the additional time required for nanofluid to heat transfer to surrounding nanoparticles is less, which is similar to the effects of concentration retardation time parameter on concentration field. Originality/value This paper aims to explore the unsteady stagnation-point flow, heat and mass transfer of upper-convected Oldroyd-B nanofluid with variable thermal conductivity and relaxation-retardation double-diffusion model.

Impact of local thermal stimulation on the correlation between oxygen saturation and speed-resolved blood perfusion

The physiologically important relationship between oxygen saturation and blood flow is not entirely understood, particularly with regard to the multiple velocity components of flow and temperature. While our previous studies used classic laser Doppler flowmetry combined with an enhanced perfusion probe to assess local blood flow following thermal stimulation, oxygen saturation signals were not assessed. Thus, the current study used multiscale entropy (MSE) and multiscale fuzzy entropy (MFE) to measure the complexity of oxygen saturation signals following thermal stimulation in healthy subjects. The results indicate that thermal stimulation increases oxygen saturation and affects the measured signal complexity in a temperature-dependent fashion. Furthermore, stimulus temperature not only affects the correlation between speed-resolved blood perfusion and oxygen saturation, but also the correlation between the complexity area indices (CAI) of the two signals. These results reflect the complexity of local regulation and adaptation processes in response to stimuli at different temperatures.

Terahertz conductivity of the magnetic Weyl semimetal Mn3Sn films

Mn3Sn is a noncollinear antiferromagnet which displays a large anomalous Hall effect at room temperature. It is believed that the principal contribution to its anomalous Hall conductivity comes from the Berry curvature. Moreover, dc transport and photoemission experiments have confirmed that Mn3Sn may be an example of a time-reversal symmetry breaking Weyl semimetal. Due to a small, but finite moment in the room temperature inverse triangular spin structure, which allows control of the Hall current with the external field, this material has garnered much interest for next generation memory devices and terahertz spintronics applications. In this work, we report a terahertz range study of randomly oriented Mn3Sn thin films as a function of temperature. At low frequencies, we found that the optical conductivity can be well described by a single Drude oscillator. The plasma frequency is strongly suppressed in a temperature dependent fashion as one enters the 260 K helical phase. This may be associated with partial gapping of the Fermi surfaces, which comes from breaking translational symmetry along the c-axis. The scattering rate shows a quadratic temperature dependence below 200 K, highlighting the possible important role of interactions in this compound.

Developmental changes in oxygen consumption and hypoxia tolerance in the heat and hypoxia-adapted tabasco line of the Nile tilapia Oreochromis niloticus, with a survey of the metabolic literature for the genus Oreochromis.

The genus Oreochromis is among the most popular of the tilapiine cichlid tribe for aquaculture. However, their temperature and hypoxia tolerance, if tested at all, is usually tested at temperatures of 20-25°C, rather than at the considerably higher temperatures of 30-35°C typical of tropical aquaculture. We hypothesized that both larvae and adults of the heat and hypoxia-adapted Tabasco-line of the Nile tilapia Oreochromis niloticus would be relatively hypoxia-tolerant. Oxygen consumption rate ( ), Q10 and aquatic surface respiration (ASR) was measured using closed respirometry at 2 (c. 0.2 g), 30 (c. 2-5 g), 105 c. (10-15 g) and 240 (c. 250 g) days of development, at 25°C, 30°C and 35°C. at 30°C was inversely related to body mass: c. 90 μM O2 g-1 /h in larvae down to c. 1 μM O2 g-1 /h in young adults. Q10 for was typical for fish over the range 25-35°C of 1.5-2.0. ASR was exhibited by 50% of the fish at pO2 of 15-50 mmHg in a temperature-dependent fashion. However, the largest adults showed notable ASR only when pO2 fell to below 10 mmHg. Remarkably, pcrit for was 12-17 mmHg at 25-30°C and still only 20-25 mmHg across development at 35°C. These values are among the lowest measured for teleost fishes. Noteworthy is that all fish maintain equilibrium, ventilated their gills and showed routine locomotor action for 10-20 min after ceased at near anoxia and when then returned to oxygenated waters, all fish survived, further indicating a remarkable hypoxic tolerance. Remarkably, data assembled for from >30 studies showed a > x2000 difference, which we attribute to calculation or conversion errors. Nonetheless, pcrit was very low for all Oreochromis sp. and lowest in the heat and hypoxia-adapted Tabasco line.

Mining the Drosophila Gustatory Receptor Family for New Thermosensitive Proteins

Gustatory receptors (Gr) are a family of transmembrane proteins that have been extensively studied in the context of insect taste and odor sensory systems. Drosophila Gr28b(D) is the first gustatory receptor shown to be involved in thermosensation. In a previous study, we showed that Gr28b(D) exhibits a non-inactivating, temperature dependent, cation non-specific current, when expressed in Xenopus laevis oocytes. More recently, we explored the temperature sensitivity of Gr28b(D) orthologs from five Drosophila species (D. yakuba, simulans, pseudoobscura, willistoni, and mojavensis) that inhabit different environments. When expressed in Xenopus oocytes, Gr28b(D) orthologs exhibit various temperature sensitivities and current densities. Additionally, when expressed in Drosophila motor neurons, along with a genetically-encoded calcium sensor (GCaMP6f), Gr28b(D) orthologs exhibit unique changes in the firing pattern of individual cells, in a temperature-dependent fashion. Finally, flies over-expressing GR28b(D) orthologs exhibit different temperature-dependent behavior. By comparing their primary structure and through mutagenesis experiments, we identified functional domains within the Gr proteins and obtained mutants with various properties. These results identify novel thermosensitive gustatory receptors in Drosophila and expand the pool of potential candidates for thermogenetics tools. They also provide clues for further structure/function studies aimed at elucidating the molecular biophysics of thermosensation.

Renormalizations in unconventional superconducting states born of normal and singular Fermi liquids

The density of low-energy particle-hole excitations is nonanalytic in a singular Fermi liquid, but it is altered on entering a superconducting state in which, in the pure limit, it vanishes asymptotically at the chemical potential and in general is analytic. The single-particle excitations in the superconducting states are then quasiparticles so that a form of Landau theory may be constructed for thermodynamic and transport properties in the superconducting state. In this theory, the renormalization of measurable properties due to quasiparticle interactions, such as specific heat, compressibility, magnetic susceptibility, superfluid density, etc., changes in a temperature dependent fashion from the noninteracting theory. This is illustrated by showing the renormalization of these quantities and the relation between the parameters introduced to account for their temperature dependence. When the renormalizations in the normal state are large or singular, temperature dependence of properties in the superconducting states are then in general not useful for identifying the nodal character or symmetry of the superconducting state except for measurements at very low temperatures, the upper limits of which are specified. The results obtained are expected to be useful in interpreting the experimental results for the temperature dependence of various properties in the superconducting state born of singular Fermi liquids.

Strong spin-orbit coupling in the noncentrosymmetric Kondo lattice

The authors investigate the properties of a two-dimensional Kondo lattice represented by a noncentrosymmetric Si-Ir-Si-Yb four-layer block at the surface of the heavy-fermion material YbIr${}_{2}$Si${}_{2}$. Strong spin-orbit coupling of Ir atoms induces spin polarization of two-dimensional itinerant surface states confined in this block, while the lattice of Yb 4$f$ moments acts as a source for coherent field interplay. Remarkably, apart from the anticipated Rashba-like splitting of the two-dimensional itinerant states, a tiny spin splitting of the Yb 4$f$ states of the block is also revealed. Electrons in these 4$f$ states interact in a temperature-dependent fashion with highly mobile spin-polarized itinerant states, gently guiding their properties.

Transport of AOPP-Albumin into Human Alveolar Epithelial A549 Cell.

Alveolar clearance of proteins, such as albumin, plays an essential role in recovery from lung injuries. Albumin is known to be oxidized by reactive oxygen species (ROS), leading to generation of advanced oxidation protein products (AOPP)-albumin in the alveolar lining fluid. In this study, we aimed to characterize the uptake of FITC-labeled AOPP-albumin (FITC-AOPP-albumin) into human alveolar epithelial cell line, A549. FITC-AOPP-albumin uptake into A549 cells and its effect of ROS generation was evaluated using fluorescence spectrometer and flow cytometry, respectively. FITC-AOPP-albumin was taken up by A549 cells in a time- and temperature-dependent fashion, and showed saturation kinetics with a Km value of 0.37 mg/mL. The uptake of FITC-AOPP-albumin was suppressed by phenylarsine oxide, a clathrin-mediated endocytosis inhibitor, but not by indomethacin and nystatin, caveolae-mediated endocytosis inhibitors, or 5-(N-ethyl-N-isopropyl) amiloride, a macropinocytosis inhibitor. AOPP-albumin induced ROS generation in A549 cells, suggesting that alveolar clearance of AOPP-albumin should be important to prevent further ROS generation. AOPP-albumin is transported into alveolar epithelial cells through clathrin-mediated endocytosis, which may be important to prevent further ROS generation.This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

Evidence for modulation of heat induced changes in erythrocytes by cytochalasin D: potential role for oxygen nanobubbles in aggregation

Thermal burn injury is associated with an increase in erythrocyte (RBC) aggregation (rouleaux) prior to fibrin clot formation; unresolved rouleaux occlude vessels and contribute to thermal burn injury progression (Clark, 2013). RBC aggregation is reversible, yet the mechanism is unknown. Current models do not include all biophysical phenomena, including the role of the cytoskeleton, and sudden oxygen release from hemoglobin. We previously proposed that thermally induced membrane deformation creates nucleation sites for excess oxygen to coalesce, i.e., form nanobubbles, which may contribute to surface tension induced aggregation. To begin to address the role of the cytoskeleton in membrane deformation through changes in the band 3‐ankyrin/adducin bridge and spectrin‐actin interactions, we have disrupted actin polymerization with cytochalasin D (cytoD). We hypothesized that disrupting the cytoskeleton would alter the apparent presence of oxygen nanobubbles on singlet RBCs. Our experimental model examines both size and greyscale appearance of RBCs with sudden changes in temperature. Temperatures of 41–49 C cause shifts in brighter greyscale and larger apparent RBC size, consistent with light diffraction through concentrated gas bubbles that dissipates with time or return to 37 C (Blasco, 2017). Washed murine RBCs (obtained through a tissue sharing program) were suspended in saline (PBS) containing 1% EtOH, 0.5 uM CytoD (in 0.1% EtOH) or control, and incubated at 37°C prior to use. RBCs settled to a monolayer within an enclosed microchannel at 37°C (heated stage). The stage temperature rapidly heated from 37°C to test temperature (37, 39, 41, 43, 45, 47, or 49°C) and we imaged at 2 Hz for 70 seconds (60X, SWI). Singlet RBCs were followed over time, measuring greyscale and apparent size of the cell (outer rim) and core (central biconcave) (ImageJ). The initial changes were seen during the temperature shift and included increased core greyscale and apparent size of 20–40% between 41–47°C, with corresponding changes in cell size. Over the next several seconds there was temperature dependent fluctuations in size and greyscale of up to 50%. Cells in EtOH were similar overall to controls. CytoD prevented changes in greyscale and in size, and suppressed further fluctuations until higher temperatures where those treated cells had formed echinocytes. The data are consistent with gas bubbles forming at the RBC membrane, causing diffraction of the light, in a temperature dependent fashion. As destabilization of the cytoskeleton prevented these changes, we conclude that the cytoskeleton contributes to membrane shape change necessary for oxygen nanobubble formation with heat.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Using Gas Phase Reactions of Hexamethylene Triperoxide Diamine (HMTD) to Improve Detection in Mass Spectrometry.

Our efforts to lower the detection limits of hexamethylene triperoxide diamine (HMTD) have uncovered previously unreported gas-phase reactions of primary and secondary amines with one of the six methylene carbons. The reaction occurs primarily in the atmospheric pressure chemical ionization (APCI) source and is similar to the behavior of alcohols with HMTD [1]. However, unlike alcohols, the amine reaction conserves the hydrogen peroxide on the intact product. Furthermore, with or without amines, HMTD is oxidized to tetramethylene diperoxide diamine dialdehyde (TMDDD) in a temperature-dependent fashion in the APCI source. Synthesized TMDDD forms very strong adducts (not products) to ammonium and amine ions in the electrospray ionization (ESI) source. Attempts to improve HMTD detection by generating TMDDD in the APCI source with post-column addition of amines were not successful. Signal intensity of the solvent related HMTD product in methanol, [HMTD+MeOH2-H2O2]+ (m/z 207.0975), was understandably related to the amount of methanol in the HMTD environment as it elutes into the source. With conditions optimized for this product, the detection of 100 pg on column was accomplished with a robust analysis of 300 pg (1.44 pmol) routinely performed on the Orbitrap mass spectrometers. Graphical Abstract ᅟ.

The Drosophila Gr28bD product is a non-specific cation channel that can be used as a novel thermogenetic tool

Extrinsic control of single neurons and neuronal populations is a powerful approach for understanding how neural circuits function. Adding new thermogenetic tools to existing optogenetic and other forms of intervention will increase the complexity of questions that can be addressed. A good candidate for developing new thermogenetic tools is the Drosophila gustatory receptor family, which has been implicated in high-temperature avoidance behavior. We examined the five members of the Gr28b gene cluster for temperature-dependent properties via three approaches: biophysical characterization in Xenopus oocytes, functional calcium imaging in Drosophila motor neurons, and behavioral assays in adult Drosophila. Our results show that Gr28bD expression in Xenopus oocytes produces a non-specific cationic current that is activated by elevated temperatures. This current is non-inactivating and non-voltage dependent. When expressed in Drosophila motor neurons, Gr28bD can be used to change the firing pattern of individual cells in a temperature-dependent fashion. Finally, we show that pan-neuronal or motor neuron expression of Gr28bD can be used to alter fruit fly behavior with elevated temperatures. Together, these results validate the potential of the Gr28bD gene as a founding member of a new class of thermogenetic tools.

Metabolome dynamics of diapause in the butterfly Pieris napi: distinguishing maintenance, termination and post-diapause phases.

Diapause is a deep resting stage facilitating temporal avoidance of unfavourable environmental conditions, and is used by many insects to adapt their life cycle to seasonal variation. Although considerable work has been invested in trying to understand each of the major diapause stages (induction, maintenance and termination), we know very little about the transitions between stages, especially diapause termination. Understanding diapause termination is crucial for modelling and predicting spring emergence and winter physiology of insects, including many pest insects. In order to gain these insights, we investigated metabolome dynamics across diapause development in pupae of the butterfly Pieris napi, which exhibits adaptive latitudinal variation in the length of endogenous diapause that is uniquely well characterized. By employing a time-series experiment, we show that the whole-body metabolome is highly dynamic throughout diapause and differs between pupae kept at a diapause-terminating (low) temperature and those kept at a diapause-maintaining (high) temperature. We show major physiological transitions through diapause, separate temperature-dependent from temperature-independent processes and identify significant patterns of metabolite accumulation and degradation. Together, the data show that although the general diapause phenotype (suppressed metabolism, increased cold tolerance) is established in a temperature-independent fashion, diapause termination is temperature dependent and requires a cold signal. This revealed several metabolites that are only accumulated under diapause-terminating conditions and degraded in a temperature-unrelated fashion during diapause termination. In conclusion, our findings indicate that some metabolites, in addition to functioning as cryoprotectants, for example, are candidates for having regulatory roles as metabolic clocks or time-keepers during diapause.

Thermal ablation of pancreatic cyst with a prototype endoscopic ultrasound capable radiofrequency needle device: A pilot feasibility study.

Background and Objectives:Pancreatic cysts are evaluated by endoscopic ultrasound and fine needle aspiration (EUS). The only accepted treatment is pancreatectomy, which is associated with morbidity and mortality. This study evaluated the optimal thermal dosimetry of a novel radiofrequency ablation device using a standard electrosurgical unit in ex vivo cyst models.Methods:A modified EUS 22-gauge monopolar needle prototype with a tip electrode connected to a standard electrosurgical unit (Erbe USA, Marietta, GA, USA) was used to induce a subboiling point temperature. A cyst model was created using 2-cm sections of porcine small intestine ligated and filled with saline. After ablation, the cyst models were prepared for pathological evaluation. The epithelial layers were measured in at least two different sites with a micrometer and compared with the corresponding control sample.Results:Thirty-two cyst models were ablated with maximum temperatures of 50°C, 60°C, 90°C, and 97°C in 8, 11, 11, and 2 cysts, respectively. Longer ablation times were required to induce higher temperatures. A trend in the reduction in thickness of the measured layers was observed after exposure to higher temperatures. A temperature over 50°C was required for the ablation of the muscularis, submucosa, and villi, and over 60°C was required to ablate the mucosal crypts.Conclusions:In a preclinical model, a novel radiofrequency EUS-capable needle connected to a standard electrosurgical unit using standard low-voltage coagulation provided ablation in a temperature-dependent fashion with a threshold of at least 60°C and a safe cyst margin below 97°C. This potentially will allow low-cost, convenient cyst ablation.

Fluorinated EuII-based multimodal contrast agent for temperature- and redox-responsive magnetic resonance imaging.

Magnetic resonance imaging (MRI) using redox-active, EuII-containing complexes is one of the most promising techniques for noninvasively imaging hypoxia in vivo. In this technique, positive (T1-weighted) contrast enhancement persists in areas of relatively low oxidizing ability, such as hypoxic tissue. Herein, we describe a fluorinated, EuII-containing complex in which the redox-active metal is caged by intramolecular interactions. The position of the fluorine atoms enables temperature-responsive contrast enhancement in the reduced form of the contrast agent and detection of the oxidized contrast agent via MRI in vivo. Positive contrast is observed in 1H-MRI with Eu in the +2 oxidation state, and chemical exchange saturation transfer and 19F-MRI signal are observed with Eu in the +3 oxidation state. Contrast enhancement is controlled by the redox state of Eu, and modulated by the fluorous interactions that cage a bound water molecule reduce relaxivity in a temperature-dependent fashion. Together, these advancements constitute the first report of in vivo, redox-responsive imaging using 19F-MRI.