Probing Behavior Research Articles

Field-Collected Glassy-Winged Sharpshooters (Hemiptera: Cicadellidae) Perform More Xylella fastidiosa-Inoculating Behaviors on Susceptible Vitis vinifera cv. 'Chardonnay' Than on Resistant Vitis champinii Grapevines.

The glassy-winged sharpshooter, Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae: Cicadellinae), is an introduced vector of the xylem-dwelling bacterium Xylella fastidiosa Wells et al. (Xanthomonadales: Xanthomonadaceae) in California. Once acquired, X. fastidiosa colonizes the functional foregut of the vector. Bacteria can be inoculated directly into grapevine xylem during the xylem cell acceptance process in sharpshooter stylet probing, represented by the X wave using electropenetrography (EPG). Since 2001, an effort has been underway to develop PD-resistant grapevines, Vitis vinifera L., through classical breeding of various species of resistant wild grapevines with more susceptible V. vinifera. The present study used EPG to compare H. vitripennis stylet probing behaviors in a factorial experiment between V. champinii (a V. candicans/V. rupestris natural hybrid with moderate trichomes) and V. vinifera cv. 'Chardonnay' (which lacks trichomes) that had been gently scraped to remove trichomes or was not scraped. Results showed that sharpshooters performed significantly more X waves/X. fastidiosa inoculation behaviors of overall longer duration on Chardonnay than on V. champinii, regardless of shaving or not-shaving to remove trichomes. In addition, trichomes caused more frequent standing/walking/test-probing behaviors on V. champinii, whose xylem was rapidly accepted for sharpshooter ingestion once probing began. Thus, EPG can detect a novel type of grapevine resistance to X. fastidiosa-to the vector's probing process and inoculation of bacteria-in addition to the bacterial infection and symptom development processes that are the basis for most resistance breeding today. Future research could use EPG to screen grapevines for this novel type of resistance.

Host plant preference of Trioza erytreae on lemon and bitter orange plants

Trioza erytreae, the African citrus psyllid, is a vector of Candidatus Liberibacter spp., the causal agent of the citrus greening disease or Huanglongbing (HLB). The spread of the vector throughout the Iberian Peninsula has been continuous since its introduction in mainland Spain in 2014. The patterns of host preference and feeding behaviour largely depend on olfactory cues. Understanding these patterns is crucial to prevent further dispersion and develop management measures against the pest. In this work, a series of settlement, olfactometric, probing, and feeding experiments were conducted to assess the host preference of T. erytreae for lemon or bitter orange plants. The settlement experiment provided evidence on the preference of both sexes of T. erytreae for lemon plants, whereas males did not show any significant choice pattern in the case of the olfactometric assays. Forty EPG variables were analysed to describe and compare the probing and feeding behaviour of T. erytreae on lemon and bitter orange plants. The EPG variables indicated that T. erytreae has some difficulties in accepting the phloem of bitter orange plants. This suggests that lemon plants would be a better source for the acquisition of Candidatus Liberibacter asiaticus (CLas) by T. erytreae since the psyllid spends much longer periods feeding from the phloem on lemon than on bitter orange.

How Different Albumin-Binders Drive Probe Distribution of Fluorescent RGD Mimetics

The biodistribution of medical imaging probes depends on the chemical nature of the probe and the preferred metabolization and excretion routes. Especially targeted probes, which have to reach a certain (sub)cellular destination, have to be guided to the tissue of interest. Therefore, small molecular probes need to exhibit a well-balanced polarity and lipophilicity to maintain an advantageous bioavailability. Labelled antibodies circulate for several days due to their size. To alter the biodistribution behavior of probes, different strategies have been pursued, including utilizing serum albumin as an inherent transport mechanism for small molecules. We describe here the modification of an existing fluorescent RGD mimetic probe targeted to integrin αvβ3 with three different albumin binding moieties (ABMs): a diphenylcyclohexyl (DPCH) group, a p-iodophenyl butyric acid (IPBA) and a fatty acid (FA) group with the purpose to identify an optimal ABM for molecular imaging applications. All three modifications result in transient albumin binding and a preservation of the target binding capability. Spectrophotometric measurements applying variable amounts of bovine serum albumin (BSA) reveal considerable differences between the compounds concerning their absorption and emission characteristics and hence their BSA binding mode. In vivo the modified probes were investigated in a murine U87MG glioblastoma xenograft model over the course of 1 wk by fluorescence reflectance imaging (FRI) and fluorescence mediated tomography (FMT). While the unmodified probe was excreted rapidly, the albumin-binding probes were accumulating in tumor tissue for at least 5 days. Considerable differences between the three probes in biodistribution and excretion characteristics were proved, with the DPCH-modified probe showing the highest overall signal intensities, while the FA-modified probe exhibits a low but more specific fluorescent signal. In conclusion, the modification of small molecular RGD mimetics with ABMs can precisely fine-tune probe distribution and offers potential for future clinical applications.

Effect of Soy Leaf Flavonoids on Pea Aphid Probing Behavior.

Simple SummaryFlavonoids are plant phenolic compounds whose biological activities include participation in plant responses to various stresses of biological and environmental origins, including protection against insect herbivore attack. We were interested in whether the specific flavonoids detected in soybean leaves have the potential to discourage the pea aphid from infesting other leguminous plants, peas in particular. We immersed the pea leaves in ethanolic solutions of the flavonoids apigenin, daidzein, genistein and kaempferol, offered them to the pea aphids and observed their behavior when they probed plant tissues with their piercing–sucking mouthparts. We discovered that aphids readily probed the pea leaves whether they were treated with flavonoids or not. However, later on, the behavior of the aphids changed depending on the flavonoid applied. Apigenin, daidzein and kaempferol caused a decrease in the intensity of plant sap ingestion. In addition, daidzein and kaempferol made the finding of sap-transporting vessels more difficult for aphids. In contrast, genistein did not affect the pea aphids’ feeding activity. Our findings provide the plant breeders and plant protection services with information on what direction their efforts should take to protect leguminous plants against aphids in a sustainable and environmentally friendly way.Flavonoids detected in soybean Glycine max (L.) Merr. (Fabaceae) cause various alterations in the metabolism, behavior, and development of insect herbivores. The pea aphid Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae) poses potential threat to soybeans, but the effect of individual flavonoids on its feeding-associated behavior is relatively unknown. We monitored probing behavior (stylet penetration activities) of A. pisum on its preferred host plant, Pisum sativum L. untreated (control) and treated with 0.1% ethanolic solutions of flavonoids apigenin, daidzein, genistein, and kaempferol. We applied the electrical penetration graph (electropenetrography, EPG) technique, which visualizes the movements of aphid stylets within plant tissues. None of the applied flavonoids affected the propensity to probe the plants by A. pisum. However, apigenin enhanced the duration of probes in non-phloem tissues, which caused an increase in the frequency and duration of stylet mechanics derailment and xylem sap ingestion but limited the ingestion of phloem sap. Daidzein caused a delay in reaching phloem vessels and limited sap ingestion. Kaempferol caused a reduction in the frequency and duration of the phloem phase. Genistein did not affect aphid probing behavior. Our findings provide information for selective breeding programs of resistant plant cultivars to A. pisum.

Isospectral Twirling and Quantum Chaos.

We show that the most important measures of quantum chaos, such as frame potentials, scrambling, Loschmidt echo and out-of-time-order correlators (OTOCs), can be described by the unified framework of the isospectral twirling, namely the Haar average of a k-fold unitary channel. We show that such measures can then always be cast in the form of an expectation value of the isospectral twirling. In literature, quantum chaos is investigated sometimes through the spectrum and some other times through the eigenvectors of the Hamiltonian generating the dynamics. We show that thanks to this technique, we can interpolate smoothly between integrable Hamiltonians and quantum chaotic Hamiltonians. The isospectral twirling of Hamiltonians with eigenvector stabilizer states does not possess chaotic features, unlike those Hamiltonians whose eigenvectors are taken from the Haar measure. As an example, OTOCs obtained with Clifford resources decay to higher values compared with universal resources. By doping Hamiltonians with non-Clifford resources, we show a crossover in the OTOC behavior between a class of integrable models and quantum chaos. Moreover, exploiting random matrix theory, we show that these measures of quantum chaos clearly distinguish the finite time behavior of probes to quantum chaos corresponding to chaotic spectra given by the Gaussian Unitary Ensemble (GUE) from the integrable spectra given by Poisson distribution and the Gaussian Diagonal Ensemble (GDE).

A novel polymeric hybrid sensory smart material for the prompt recognition of mercury ions in water

An acrylamide-xanthene hybrid polymeric probe was synthesized for the selective and sensitive detection of mercury ions (Hg2+) in 100% water. The non-polymeric form of probe displayed extraordinary selectivity above other additional metal cations via both a visual color change and fluorescence change with exceptional reversibility and responds rapidly to changes in the environment. The 1H NMR titration study revealed the binding of an Hg2+ ion on the imine hydrogen of the probe by the opening of the spiro-lactam ring, which instigates an instant color change. Reversible behavior of the polymeric probe using an aqueous solution of EDTA was confirmed by both absorption and fluorescence studies. The prepared polymeric probe detects Hg2+ in 100% water and is a promising material for the mercury recognition in real-time.

Crystal Structures and Luminescent Probe Behaviors of Three-Dimensional Zn(II) Frameworks with Multicarboxylate and Tetradentate Imidazole-Containing Ligands

Crystal Structures and Luminescent Probe Behaviors of Three-Dimensional Zn(II) Frameworks with Multicarboxylate and Tetradentate Imidazole-Containing Ligands

Antixenosis in Glycine max (L.) Merr against Acyrthosiphon pisum (Harris)

To reveal the antixenosis potential against the pea aphid Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae) we analyzed the pea aphid survival and probing behavior, and the quantitative and qualitative variation of flavonoids in the leaves of selected soybean Glycine max (L.) Merr (Fabaceae) cultivars ‘Aldana’, ‘Annushka’, ‘Augusta’, ‘Madlen’, ‘Mavka’, ‘Simona’, ‘Violetta’, and ‘Viorica’. Aphid survival was drastically impeded on all cultivars. The electronic monitoring of aphid probing using the Electrical Penetration Graph (EPG) technique revealed that on all soybean cultivars, A. pisum readily probed into leaf tissues but the probes were usually terminated before reaching vascular tissues, which demonstrates the activity of antixenosis mechanisms in peripheral tissues epidermis and/or mesophyll in soybean leaves. The potency of antixenosis factors differed among soybean cultivars, which was reflected in differences in aphid survival and frequency and duration of phloem sap ingestion. Seven flavonoids were found: apigenin, daidzein, genistein, glycitein, isorhamnetin, kaempferol, and rutin, which occurred in different amount and proportion in individual cultivars. The content of apigenin and genistein in all soybean cultivars studied probably made them relatively unacceptable to A. pisum. Kaempferol in ‘Aldana’ might be responsible for the observed strong antixenosis resistance of this cultivar to A. pisum. The results of our survey provide the first detailed data that can be used for future studies.

Effects of Long-Term Exposure to Electrostatic Radiation on the Mean Relative Growth Rate and Feeding Behavior of Sitobion avenae (Hemiptera: Aphididae)

Abstract Previous research has indicated that electrostatic radiation may induce biological and physiologic changes in plants and aphids. This study was conducted to determine effects of long-term exposure of electrostatic radiation on biology and feeding behavior of Sitobion avenae (F.). To imitate the natural electrostatic radiation stress, both wheat seeds and S. avenae nymphs (produced within 12 h) were exposed to an electrostatic radiation of 4 kV/cm for 20 min and 5 kV/cm intensity for 40 min, respectively. Controls received no treatment (0 kV/cm). Then, the mean relative growth rate (MRGR) and feeding behavior of the 5th-, 10th-, 15th-, 20th-, 27th-, 33rd-, and 39th-generation aphids were examined, respectively. Data showed that electrostatic radiation exposure within a certain period of time can promote weight increases of S. avenae, but long-term exposure of electrostatic radiation had an adverse effect on the weight gain of aphids. The comparison of the two treatment intensities showed that electrostatic radiation at the intensity of 4 kV/cm for 20 min had a significant influence on the probing behavior of S. avenae. This study initially evaluated the effect of electrostatic radiation on S. avenae from the aspect of nutrient feeding behavior, which further verifies the biological characteristics of electrostatic radiation.

Comparison of the reactivity of isomeric 2H‐ and 3H‐naphthopyran mechanophores

AbstractNaphthopyrans are molecular switches that produce highly colored merocyanine dyes upon photochemical or mechanochemical activation in polymers. The mechanochromic behavior of these molecular force probes enables the straightforward visualization of stress and/or strain in materials. To date, research on the mechanochemistry of naphthopyran has largely focused on the 3H‐naphtho[2,1‐b]pyran (3H) scaffold, whereas isomeric 2H‐naphtho[1,2‐b]pyrans (2H) exhibit complementary properties as suggested from their photochemical reactivity. Here we directly compare the reactivity of two isomeric 2H‐ and 3H‐naphthopyran mechanophores in solution‐phase ultrasonication experiments and in crosslinked polydimethylsiloxane elastomers subjected to uniaxial tensile deformation. The prototypical 3H‐naphthopyran mechanophore produces a yellow merocyanine dye that reverts quickly, while the 2H‐naphthopyran mechanophore generates a red merocyanine dye that reverts significantly slower. The trends in absorption and reversion measured in solution are also reflected in solid polymeric materials activated in tension. Building on recent research into substituent effects, this study identifies naphthopyran isomerism as a simple lever for modulating the mechanochromic properties of the naphthopyran mechanophore used in the development of force‐responsive polymers.

Quercetin and Rutin as Modifiers of Aphid Probing Behavior.

Rutin and its aglycone quercetin occur in the fruits, leaves, seeds, and grains of many plant species and are involved in plant herbivore interactions. We studied the effect of the exogenous application of rutin and quercetin on the probing behavior (= stylet penetration activities in plant tissues) of Acyrthosiphon pisum on Pisum sativum, Myzus persicae on Brassica rapa ssp. pekinensis, and Rhopalosiphum padi on Avena sativa using the electrical penetration graph technique (EPG = electropenetrography). The reaction of aphids to quercetin and rutin and the potency of the effect depended on aphid species, the flavonol, and flavonol concentration. Quercetin promoted probing activities of A. pisum within non-phloem and phloem tissues, which was demonstrated in the longer duration of probes and a trend toward longer duration of sap ingestion, respectively. M. persicae reached phloem in a shorter time on quercetin-treated B. rapa than on the control. Rutin caused a delay in reaching sieve elements by A. pisum and deterred probing activities of M. persicae within non-phloem tissues. Probing of R. padi was not affected by quercetin or rutin. The potency of behavioral effects increased as the applied concentrations of flavonols increased. The prospects of using quercetin and rutin in plant protection are discussed.

Exploring the Influence of Different Albumin Binders on Molecular Imaging Probe Distribution.

The biodistribution of molecular imaging probes or tracers mainly depends on the chemical nature of the probe and the preferred metabolization and excretion routes. Small molecules have rather short half-lives while antibodies reside inside the organism for a longer period of time. An excretion via kidneys and bladder is faster than a mainly hepatobiliary elimination. To manipulate the biodistribution behavior of probes, different strategies have been pursued, including utilizing serum albumin as an inherent transport mechanism for small molecules. Here, we modified an existing small molecular fluorescent probe targeted to the endothelin-A receptor (ETAR) with three different albumin-binding moieties to search for an optimal modification strategy. A diphenylcyclohexyl (DPCH) group, a p-iodophenyl butyric acid (IPBA), and a fatty acid (FA) group were attached via amino acid linkers. All three modifications result in transient albumin binding of the developed compounds, as concluded from gel electrophoresis investigations. Spectrophotometric measurements applying variable amounts of bovine, murine, and human serum albumin (BSA, MSA, and HSA) reveal distinct variations of absorption and emission intensities and shifts of their maximum wavelengths. Binding to MSA results in the weakest effects, while binding to HSA leads to the strongest. Cell-based in vitro investigations utilizing ETAR-positive HT-1080 fibrosarcoma and ETAR-negative BT-20 breast adenocarcinoma cells support a retained specific target-binding capacity of the modified compounds and different degrees of unspecific binding. In vivo analysis of a HT-1080 xenograft model in nude mice over the course of 1 week by fluorescence reflectance imaging illustrates noticeable differences between the four examined probes. While the IPBA-modified probe shows the highest absolute signal intensity values, the FA-modified probe exhibits the most favorable tumor-to-organ ratios. In summary, reversible binding to albumin enhances the biological half-life of the designed probes substantially and enables near infrared optical imaging of subcutaneous tumors for several days in vivo. Because the unmodified probe already exhibits reasonable results, the attachment of albumin-binding moieties does not lead to a substantially improved imaging outcome in terms of target-to-background ratios. On the other hand, because the implemented transient albumin binding results in an overall higher amount of probe inside tumor lesions, this strategy might be adaptable for theranostic or therapeutic approaches in a future clinical routine.

Probing behavior of Adelges laricis Vallot (Hemiptera: Adelgidae) on Larix decidua Mill: Description and analysis of EPG waveforms.

Adelgidae are a sister group of Aphididae and Phylloxeridae within Hemiptera, Aphidoidea and occur exclusively on Pinaceae. The piercing-sucking mouthparts of Adelgidae are similar to those of aphids and it is believed that adelgids ingest sap from both the non-vascular and vascular (phloem) tissues. The aim of the present study was to identify and characterize the adelgid stylet activities during their penetration in plant tissues. The probing behavior of Adelges laricis Vallot (Hemiptera: Adelgidae) on European larch Larix decidua Mill. and sucrose diets was monitored using the DC-EPG (Electrical Penetration Graph technique = electropenetrography). The EPG waveforms were described based on amplitude, frequency, voltage level, and electrical origin of the observed traces, and associated with putative behavioral activities based on analogy with aphid activities. Waveform frequency, duration, and sequence were analysed as well. A. laricis generated EPG signals at two clearly distinct voltage levels positive and negative, suggesting extracellular and intracellular stylet penetration, respectively. The adelgid EPG patterns were ascribed to four behavioral phases, which were non-probing, pathway, phloem, and xylem phases. Non-probing referred to the position of the stylets outside the plant tissues. Pathway phase was represented by three waveform patterns that visualized extracellular stylet penetration in non-vascular tissues without potential drops (AC1), with serial short (1.2–1.5 s) potential drops (AC2), and with ‘aphid-like’ (5–10 s) potential drops (AC3). Phloem phase comprised three waveform patterns at intracellular level, which in all probability represented phloem salivation (AE1), and phloem sap passive (AE2) and active ingestion (AE3). AE3 was a newly described waveform, previously unreported from Hemiptera. Waveform AG represented the ingestion of xylem sap. The comparative analysis demonstrated that the gymnosperm-associated adelgids show certain similarities in probing behavior typical of aphids and phylloxerids on angiosperm plants. The present work is the first detailed analysis of specific adelgid stylet activities on gymnosperms.

Effect of Cardinium Infection on the Probing Behavior of Bemisia tabaci (Hemiptera: Aleyrodidae) MED.

Facultative endosymbionts can affect the growth, physiology, and behavior of their arthropod hosts. There are several endosymbionts in the invasive whitefly Bemisia tabaci Mediterranean (MED, Q biotype) that influence host fitness by altering stylet probing behavior. We investigated the probing behavior of B. tabaci MED infected with the facultative endosymbiont Candidatus Cardinium hertigii (Cardinium (Sphingobacteriales: Flexibacteraceae)). We generated genetically similar Cardinium-infected (C*+) and uninfected (C-) clonal sublines and analyzed the probing behavior of newly emerged adult on cotton (Malvales: Malvaceae), Gossypium hirsutum L., using electropenetrography (EPG). The C- subline demonstrated a longer duration of E2 (2.81-fold) and more events of E2 (2.22-fold) than the C*+ subline, indicating a greater level of sustained ingestion of plant phloem. These findings provide insight into the fitness costs (fitness of a particular genotype is lower than the average fitness of the population) of the Cardinium-infected B. tabaci.

Optical Interrogation of Metabotropic Glutamate Receptor‐Mediated Modulation of Cortical Circuits using Optimized Photoswitchable Tethered Ligands

G protein-coupled receptors (GPCRs) form a large family of membrane bound receptors that initiate intracellular responses which control cellular signaling cascades to contribute to a wide range of biological functions. The metabotropic glutamate receptors (mGluRs) consist of an eight-member family of class C GPCRs that respond to the excitatory neurotransmitter glutamate and serve as promising pharmacological targets for a range of neurological and psychiatric disorders. Studies targeting mGluR2 and mGluR3, the group II Gi/o-coupled subfamily of mGluRs, have shown that they are strong modulators of frontal cortex activity and associated behaviors. However, the lack of spatiotemporal precision and specificity of classical pharmacological and genetic approaches has limited our mechanistic understanding of these receptors. Here we report an improved chemical optogenetic toolkit that permits the reversible and repeatable activation of group II mGluRs with genetic targeting, subtype-specificity and spatiotemporal precision in vivo. Through introduction of branches and tuning of azobenzene photophysics, we have produced a family of tethered photoswitchable glutamate compounds that enable dual control and visualization of mGluRs in vivo with robust speed and efficiency. We use these tools to probe the effects of mGluR2 activation within different cell-types and corticolimbic circuits while probing behaviors associated with anxiety, depression and cognitive disorders.

Fast response transient behaviour of a coaxial thermal probe and recovery of surface heat flux for shock tube flows

The magnitude of surface heat flux and its accurate estimation are very crucial owing to their applicability in impulsive thermal loads for high-speed flights. The correctness of such heat flux is associated with the implications from highly responsive thermal sensors in ground-based aerodynamic studies. In the present study, the performance effectiveness of an indigenous, in-house-made coaxial thermal probe (CTP) is validated against a standard silver thin film gauge (TFG) counterpart. The thermal probe has been fabricated in-house from two metal alloys; chromel (3.25 mm diameter and 10 mm length) and constantan (0.91 mm diameter and 15 mm length), by disposing one in the annulus of another coaxially, subsequently clubbed by a thin layer of epoxy in between them. Similarly, the thin film gauge is fabricated by putting silver paste (~1 µm thickness) on the pyrex substrate (3.25 mm diameter, 10 mm length). The fabrication process is followed by different calibration activities to determine the characteristics constants for sensors (sensitivity, thermal product value for CTP, and temperature coefficient of resistance for TFG). Both the probes are tested in a highly transient environment in a shock tube that generates high density, high pressure, and high enthalpy flows. The response time of the CTP and TFG are found to be 265 µs and 240 µs, respectively. The heat flux values estimated through temperature responses are having a nice match for CTP as well as TFG with a deviation in peak heat flux value within a range of ±2%. A similar trend and magnitude are also re-assured through numerical simulation within an uncertainty band of ±1.5%. The exhaustive study carried out in a shock tube has assured the performance and reliability of a CTP. Hence, it is recommended as an effective heat flux sensor for routine measurements in impulsive heat loadings.

Electrochemical detection of Cr(III) and Cr(VI) in solution by using ZrO2 modified magnetic nanoparticles by redox probes

Herein, modified Fe3O4 magnetic nanoparticles by ZrO2 (MNPZs) were prepared by co-precipitation method. Prepared MNPZs were characterized with XRD, SEM, EDX, TEM, FTIR and VSM techniques. In addition, a modified magnetic carbon paste electrode (CPE) by MNPZ was prepared, and its interaction with Cr(III) and Cr(VI) ions was investigated in the presence of [Fe(CN)6]3-/4- and PBQ/H2Q redox probes via CV and EIS. An electrochemical technique based on observed behavior of redox probes with accumulated each forms of chromium was developed for speciation of Cr(III) and Cr(VI) in this work. Accumulated Cr(III) on CPE/MNPZ showed electrostatic attraction toward [Fe(CN)6]3-/4- redox probe and accumulated Cr(VI) showed a blocking behavior toward PBQ/H2Q redox probe. According to different behaviors of Cr(III) and Cr(VI) at electrode interface in the presence of redox probes, a new calibration for each forms of chromium ions and an entire protocol for Cr speciation are proposed based on voltammetry and impedimetry. After optimization of affecting experimental parameters on the electrode response, linear calibration curves from 1.0 × 10-9 to 1.0 × 10-3 M with sensitivity as 3.41 μA/M and detection limit (DL) as 8.1 × 10-10 M, and from 1.0 × 10-9 to 1.0 × 10-6 M with sensitivity as 4.07 kΩ/M and DL as 6.9 × 10-11 M, were obtained for Cr(III) by using [Fe(CN)6]3-/4- as a redox probe in CV and EIS methods, respectively. Also, linear calibration curves from 5.0 × 10-9 to 1.0 × 10-4 M with sensitivity as 1.79 μA/M and DL as 5.3 × 10-10 M, and from 1.0 × 10-9 to 5.0 × 10-5 M with sensitivity as 7.05 kΩ/M and DL as 4.5 × 10-10 M, were observed for Cr(VI) when use PBQ/H2Q as redox probe in CV and EIS methods, respectively.

Cyanobiphenyl-spiropyrane and -hemicyanine conjugates for cyanide detection in organic/aqueous media through reverse ICT direction: Their practical applications

Cyanide is one of the most known toxic substances. It is used in many industries and threats human health and environment through releasing with wastewater. Therefore, it is very important to detect its accurate amount, rapidly. Herein, turn-on and turn-off fluorescence sensors of hybrid cyanobiphenyl-spiropyrane and -hemicyanine were developed for the detection of CN− ions on the basis of nuchleophilic addition to indolium moiety. Detection behavior of the both probes toward a series of anions was investigated by means of fluorescence, UV–vis, NMR and TOF-MS techniques. The results obviously indicate that both probes show remarkable spectral changes and high selectivity toward CN− with respect to other tested anions. Cyanide levels in water samples up to 0.208 μM could be quantitatively detected as practical application. A smartphone imaging application was successfully constructed for CN− detection. Noticeably, production of cotton kids and PSF capsules revealed that the probe could be conveniently used for on-site measurement of cyanide without complicated instruments.

Alteration in the Stylet Probing Behavior and Host Preference of the Vector Matsumuratettix hiroglyphicus (Hemiptera: Cicadellidae) After Infection with Sugarcane White Leaf Phytoplasma.

The leafhopper (Matsumuratettix hiroglyphicus (Matsumura) (Hemiptera: Cicadellidae)) is a crucial insect vector of the phytoplasma associated with sugarcane white leaf (SCWL) disease. The aim of this study was to compare the stylet probing behaviors of M. hiroglyphicus on healthy sugarcane plants, asymptomatic, and symptomatic SCWL-infected sugarcane plants, using DC electropenetrography. We also used host-selection preference (free-choice) assays to identify the preferred types of host plants, and scanning electron microscopy to observe stylet puncture holes and salivary flanges after leafhopper probing. According to a quantitative analysis of M. hiroglyphicus stylet probing, mean durations per insect of both phloem ingestion (waveform D; the phytoplasma-acquisition behavior) and phloem salivation (waveform C; the phytoplasma-inoculation behavior) were significantly longer on both types of infected sugarcane than on healthy plants. These longer overall durations were mainly because the same number of significantly longer-duration C and D events was performed on infected sugarcane compared with healthy plants. On free-choice tested plants, M. hiroglyphicus displayed a significantly greater preference to settle on the infected plants (both types) than the healthy sugarcane. These results provide the first empirical evidence that acquiring the SCWL phytoplasma alters the host selection and stylet probing behaviors of its main vector (M. hiroglyphicus). Our study thus contributes to a better understanding of the interactions between the insect vector and SCWL phytoplasma-infected plants, and will aid in developing novel disease management tactics for sugarcane.

Interfacial association of ferritin with anionic fluorescent probe at the 1,2-dichloroethane/water interface

• ANS − effectively associates with ferritin subunits in the aqueous solutions. • The ferritin subunits strongly adsorbed at the interface. • The transfer of ANS − was depressed by ferritin adsorbed at the interface. • ANS − dissociated from ferritin was transferred across the interface. The interfacial behavior of an anionic fluorescent probe, 8-anilino-1-naphthalenesulfonate (ANS − ), was investigated in the presence of an iron-storage protein, ferritin which has the potential as a stimuli-responsive molecular capsule at the 1,2-dichloroehtane (DCE)/water interface. The fluorescence of ANS was drastically enhanced in water by adding ferritin under acidic conditions, where the electrochemical responses of ANS − at the interface was affected via the association with ferritin subunits. At pH 2.1, the spectroelectrochemical analysis demonstrated that the interfacial adsorption of ferritin subunits stably associated with ANS was independent on the applied potential, i.e., strong adsorption. Around the isoelectric point of ferritin (pH ≈ 4), the transfer responses of ANS − were depressed with negative potential shifts, indicating that the molecular association behavior of ferritin species is pH-responsive and the transfer process of anionic species can be controlled by adding ferritin.