TRPV channel nanchung and TRPA channel water witch form insecticide-activated complexes

We have previously shown that insect vanilloid-type transient receptor potential (TRPV) channels Nanchung (Nan) and Inactive (Iav) form complexes, which can be over-stimulated and eventually silenced by commercial insecticides, afidopyropen, pymetrozine and pyrifluquinazon. Silencing of the TRPV channels by the insecticides perturbs function of the mechano-sensory organs, chordotonal organs, disrupting sound perception, gravitaxis, and feeding. In addition to TRPV channels, chordotonal organs express an ankyrin-type transient receptor potential (TRPA) channel, Water witch (Wtrw). Genetic data implicate Wtrw in sound and humidity sensing, although the signaling pathway, which links Wtrw to these functions has not been clearly defined. Here we show that, in heterologous system, Nan and Wtrw form calcium channels, which can be activated by afidopyropen, pymetrozine and an endogenous agonist, nicotinamide. Analogous to Nan-Iav heteromers, Nan forms the main binding interface for afidopyropen, whereas co-expression of Wtrw dramatically increases its binding affinity. Pymetrozine competes with afidopyropen for binding to Nan-Wtrw complexes, suggesting that these compounds have overlapping binding sites. Analysis of Drosophila single-nucleus transcriptomic atlas revealed co-expression of nan and wtrw in audio- and mechanosensory neurons. The observation that Nan can form insecticide-sensitive heteromers with more than one type of TRP channels, raises a possibility that Nan may partner with some other TRP channel(s). In addition, we show that Wtrw can be activated by plant-derived reactive electrophiles, allyl isothiocyanate and cinnamaldehyde, defining new molecular target for these repellents.

Serological markers of gluten sensitivity in Border terriers with gall bladder mucocoeles

OBJECTIVES

To evaluate serological markers of gluten sensitivity in conjunction with cholecystokinin measurement in Border terriers with gall bladder mucocoeles.

MATERIALS AND METHODS

Medical records from two referral hospitals were obtained between 2011 and 2019 to identify Border terriers with gall bladder mucocoeles, non-Border terriers with gall bladder mucocoeles and control Border terriers with non-biliary diseases. Enzyme-linked immunosorbent assays were performed on stored fasted serum samples for anti-gliadin IgG, anti-canine transglutaminase-2-IgA autoantibodies and cholecystokinin. Statistical analysis was performed using the Kruskall-Wallis test to identify differences between the groups.

RESULTS

Fifteen Border terriers with gall bladder mucocoeles, 17 non-Border terriers with gall bladder mucocoeles and 14 control Border terriers with non-biliary diseases were recruited. Median transglutaminase-2-IgA autoantibodies in Border terriers with gall bladder mucocoeles was 0.73 (range: 0.18 to 1.67), which was significantly greater than in control Border terriers at 0.41 (0.07 to 1.14). Median cholecystokinin concentration in Border terriers with gall bladder mucocoeles was 13 pg/mL (6 to 45 pg/mL), which was significantly lower than in control Border terriers at 103 pg/mL (9 to 397 pg/mL). There was no difference in the anti-gliadin IgG between these groups. There was no difference observed in the non-Border terriers with gall bladder mucocoeles with either of the other groups.

CLINICAL SIGNIFICANCE

Reduced cholecystokinin and increased transglutaminase-2-IgA autoantibodies was detected in Border terriers with gall bladder mucocoeles; which is in part homologous to gall bladder disease identified in human coeliac disease. The results suggest an immunological disease with impaired cholecystokinin release may be affecting gall bladder motility and possibly contributing to mucocoele formation in Border terriers.

Differential metabolism of neonicotinoids by brown planthopper, Nilaparvata lugens, CYP6ER1 variants

Imidacloprid is very effective in controlling Nilaparvata lugens Stål, which severely damages rice plants. Following heavy imidacloprid use, imidacloprid-resistant N. lugens, which showed cross-resistance to other neonicotinoids, appeared. We used the baculovirus/Sf9 expression system to express CYP6ER1 variants carrying A375del + A376G (del3) mutations, either with or without T318S mutation, which confer imidacloprid resistance in N. lugens. These CYP6ER1 variants metabolized imidacloprid but did not metabolize dinotefuran. Moreover, Drosophila expressing a CYP6ER1 variant carrying T318S + del3 mutations were resistant to imidacloprid, with a resistance ratio of 288.7, whereas the resistance ratio to dinotefuran was 3.6. These findings indicate that N. lugens has a low level of resistance to dinotefuran, and the increase of resistance is slow. We also studied the metabolism of other neonicotinoids, as well as sulfoxaflor and flupyradifurone, by CYP6ER1 variants carrying del3 mutations, either with or without the T318S mutation. Sulfoxaflor, was not metabolized by either CYP6ER1-del3 or CYP6ER1-T318Sdel3 variants. However, these variants did metabolize flupyradifurone. This study sheds light on the substrate selectivity of CYP6ER1 variants.

Pymetrozine activates TRPV channels of brown planthopper Nilaparvata lugens

The commercial insecticide pymetrozine has been extensively used for brown planthopper control in East Asia. The transient receptor potential vanilloid (TRPV) channel, which consists of two proteins, Nanchung (Nan) and Inactive (Iav), has recently been shown to be the molecular target of pymetrozine in the fruit fly (Drosophila melanogaster) and pea aphid (Acyrthosiphon pisum). In this study, we characterized the Nan and Iav TRPV channel subunits of N. lugens and measured the action of pymetrozine on them. NlNan and NlIav are structurally similar to homologs from other insects. The expression pattern analysis of various body parts showed that NlNan and NlIav were both more abundantly expressed in antennae. When NlNan and NlIav were co-expressed in Xenopus laevis oocytes, they formed channels with high sensitivity to pymetrozine (EC₅₀ = 5.5 × 10^-8 M). Behavioral observation revealed that the gravitaxis defect in the fruit fly nan^36a mutant was rescued by ectopically expressed NlNan and the rescued behavior could be abolished by pymetrozine. Our results confirm that NlNan and NlIav co-expressed complexes can be activated by pymetrozine both in vitro and in vivo and provide useful information for future resistance mechanism studies.

Afidopyropen: New and potent modulator of insect transient receptor potential channels

The commercial insecticides pymetrozine and pyrifluquinazon control plant-sucking pests by disturbing their coordination and ability to feed. We have previously shown that these compounds act by overstimulating and eventually silencing vanilloid-type transient receptor potential (TRPV) channels, which consist of two proteins, Nanchung and Inactive, that are co-expressed exclusively in insect chordotonal stretch receptor neurons. Here we show that a new insecticidal compound, afidopyropen, modulates chordotonal organs of American grasshoppers (Schistocerca americana) in the same fashion. Afidopyropen stimulated heterologously expressed TRPV channels from two different insect species - fruit fly (Drosophila melanogaster) and pea aphid (Acyrthosiphon pisum) - but did not affect function of the mammalian TRPV channel TRPV4. Activation of the insect TRPVs required simultaneous expression of both Nanchung and Inactive proteins. Tritium-labeled afidopyropen bound fruit fly TRPVs with higher affinity than pymetrozine and competed with pymetrozine for binding. Nanchung protein formed the main binding interface for afidopyropen, whereas co-expression of Inactive dramatically increased binding affinity. Another modulator of chordotonal organs, flonicamid, did not activate insect TRPV channels, nor did it compete with afidopyropen for binding, indicating that it has a different target site. These results define afidopyropen as a new, potent and specific modulator of insect TRPV channels, and provide insight into the unique binding mode of these compounds.

The cell-surface proteoglycan Dally regulates Wingless signalling in Drosophila

Wingless (Wg) is a member of the Wnt family of growth factors, secreted proteins that control proliferation and differentiation during development. Studies in Drosophila have shown that responses to Wg require cell-surface heparan sulphate, a glycosaminoglycan component of proteoglycans. These findings suggest that a cell-surface proteoglycan is a component of a Wg/Wnt receptor complex. We demonstrate here that the protein encoded by the division abnormally delayed (dally) gene is a cell-surface, heparan-sulphate-modified proteoglycan. dally partial loss-of-function mutations compromise Wg-directed events, and disruption of dally function with RNA interference produces phenotypes comparable to those found with RNA interference of wg or frizzled (fz)/Dfz2. Ectopic expression of Dally potentiates Wg signalling without altering levels of Wg and can rescue a wg partial loss-of-function mutant. We also show that dally, a regulator of Decapentaplegic (Dpp) signalling during post-embryonic development, has tissue-specific effects on Wg and Dpp signalling. Dally can therefore differentially influence signalling mediated by two growth factors, and may form a regulatory component of both Wg and Dpp receptor complexes.

Detection of arterial intimal lesions: an experimental study comparing ultrasonography and arteriography

In an experimental study the diagnostic value of intra-operative ultrasonography in the detection of arterial intimal lesions was investigated. A human carotid artery was placed in a pulsatile circuit with a roller pump and tubes. Intimal lesions (1-5 mm) were created and ultrasonography and biplane arteriography were performed. The ultrasonograms and arteriograms obtained were interpreted by three observers, who were blind to the procedures performed and the results were compared to the macroscopic defects. The mean sensitivity between observers for ultrasonography was 84% with a specificity of 95.7%. For biplane arteriography the mean sensitivity was 42% with a specificity of 94.5%. The differences between ultrasonography and biplane arteriography were statistically significant (p less than 0.02). It is concluded from this is concluded from this in vitro study that ultrasonography provides more accurate information concerning intimal lesions of the arterial wall than biplane arteriography.

Color-flow duplex criteria for grading stenosis in infrainguinal vein grafts

Color-flow duplex scanning of infrainguinal vein bypasses was used to identify failing grafts. Several duplex parameters were compared to determine their value in identifying and quantifying the degree of stenosis. Intraarterial digital subtraction angiography was used as the "gold standard" to determine the severity of the stenosis. The goal of this study was to identify specific color-flow duplex criteria for grading stenotic lesions. After a retrospective analysis some of these parameters were prospectively validated. The surveillance protocol required a color-flow duplex scan every 3 months for the first year and every 6 months during the second year. One hundred sixteen vein grafts in 112 patients were studied. Forty-three stenoses were identified and classified into categories from 30% to 49%, 50% to 69%, and 70% to 99% diameter reduction. These stenoses were identified in either the bypass graft or adjacent inflow or outflow arteries. Failing grafts were evaluated further by intraarterial digital subtraction angiography. Patients with normal appearing bypasses (without suspected stenotic lesions) had intravenous digital subtraction angiography. The five duplex parameters that were studied included the following: (1) graft peak systolic velocity (PSV-graft), (2) the maximum peak systolic velocity (at the site of a stenosis or in normal grafts at the narrowest segment of the bypass) (PSV-max), (3) the ratio between PSV-graft and PSV-max, (PSV-index), (4) end-diastolic velocity (EDV) at a stenosis or from narrowest graft segment, (5) color-flow image diameter measurements. For discrimination of different degrees of stenosis, threshold values of these parameters were calculated by receiver operating characteristic analysis. Diameter reduction measured by color-flow imaging was best to identify all stenotic lesions greater than 29% (sensitivity 88%, specificity 99%). Peak systolic velocity-index proved optimal identification of stenoses greater than 49% (sensitivity 89%, specificity 92%), and 70% to 99% stenoses were associated with increased EDV (sensitivity 91%, specificity 100%). The PSV-index criteria were then validated prospectively in a separate group of vein grafts. The data support the value of surveillance of femorodistal vein grafts and demonstrate that calculation of the degree of graft stenosis is feasible.

Complete acromioclavicular dislocations: treatment with a Dacron ligament

A series of 20 patients was treated for a complete acromioclavicular dislocation (Tossy III). Reduction of the clavicle is maintained by a Dacron ligament, which provides dynamic fixation. The mean follow-up period was 3.9 years. For 19 patients the results were good or excellent; in one case the result was poor. Advantages of the method described are ease of the procedure, absence of pins and a 1-week period of immobilization. An important result is the short sick leave with an average of 3.3 weeks, which is favourable compared with other operative and non-operative methods. The recent tendency to treat complete acromioclavicular dislocations non-operatively is based on the poor results of the Phemister and Bosworth operation; however, cerclage with a Dacron ligament has a low complication rate and gives a high percentage of anatomical reduction. It is therefore considered an effective method to treat complete acromioclavicular dislocations.