Molecular Insights into the Insensitivity of Lepidopteran Pests to Cycloxaprid

Cycloxaprid (CYC) is effective in the control of hemipteran pests, but its bioactivity against lepidopteran pests is still unclear. Here, the bioactivity of CYC against lepidopteran pests was found to be much worse than that against hemipteran insects. To reveal the mechanism, the transcriptomes of CYC-treated and untreated Ostrinia furnacalis larvae were compared. Among the top 20 differentially expressed genes, 11 encode proteins involved in cuticle formation, while only one encodes a detoxifying enzyme. Thus, the cuticle appears to be important for the insensitivity of O. furnacalis to CYC. A pretreatment of O. furnacalis larvae with methoprene enhanced the bioactivity of CYC by 1.12-fold. Moreover, mixtures of CYC with graphene oxide increased the bioactivity of CYC by 1.88-fold. Because lepidopteran and hemipteran insects often harm crops at the same time, the work can help make full use of CYC and reduce the environmental impacts of using multiple pesticides

Group h Chitinase: A Molecular Target for the Development of Lepidopteran-Specific Insecticides

Sustainable agriculture requires insecticides that are selective between insects and mammals and even between harmful and beneficial insects. Lepidoptera includes the largest number of insect pests that threaten crops, and Hymenoptera contains the natural enemies for these pests. Discovery of lepidopteran-specific molecular targets is one route to develop such selective pesticides. Group h chitinase (Chi-h) is an ideal target for lepidopteran-specific insecticides because it is only distributed in Lepidoptera and is critical to their molting processes. This minireview focuses on the latest progress in developing Chi-h as a lepidopteran-specific insecticide target. We describe the biological function, crystal structure, and small-molecule inhibitors of the enzyme. Notably, two unique pockets were discovered in the crystal structure of Chi-h for the binding of the selective inhibitors, phlegmacin B1 and lynamicin B. Moreover, lynamicin B was found to exhibit significant insecticidal activity toward lepidopteran pests but is harmless toward their natural enemies. These findings are advancing the development of selective insecticides to meet the needs of sustainable agriculture

Short-Term Reproducibility of Twenty-Four-Hour Intraocular Pressure Curves in Untreated Patients with Primary Open-Angle Glaucoma and Ocular Hypertension

<div><p>Purpose</p><p>To assess the short-term day-to-day reproducibility of 24-hour intraocular pressure (IOP) curves in various respects in untreated primary open-angle glaucoma (POAG) and ocular hypertension (OHT) patients.</p><p>Methods</p><p>47 subjects with POAG and 34 subjects with OHT underwent IOP measurements every 2 hours in both eyes for consecutive 48 hours by a non-contact tonometer (NCT). IOP values at each time point were recorded. Mean IOP, peak IOP, time difference of peak IOP between two days and IOP fluctuation were also calculated. Intraclass correlation coefficients (ICCs) and Bland-Altman plots were used to evaluate reproducibility.</p><p>Results</p><p>ICCs of the entire IOP values for a complete 24-hour curve were 0.577 and 0.561 in POAG and OHT patients, respectively. ICCs of IOP values at different time points ranged from 0.384 (10am) to 0.686 (4am) in POAG patients and from 0.347 (6am) to 0.760 (4am) in OHT patients. ICCs of mean IOP, peak IOP and IOP fluctuation were respectively 0.832, 0.704, 0.367 in POAG patients and 0.867, 0.816 0.633 in OHT patients. Only 37.23% and 35.29% of the peak IOP time points appeared within the time difference of 2 hours in POAG and OHT patients, respectively, while 53.19% and 48.53% appeared within 4 hours in POAG and OHT patients, respectively.</p><p>Conclusion</p><p>A 24-hour IOP curve in a single day is not highly reproducible in short-term and has limited use for evaluating individual IOP condition. Mean IOP and peak IOP for a 24-hour IOP curve are useful parameters in clinical follow-up, while IOP value at a certain time point, IOP fluctuation and peak IOP time point should be interpreted with caution.</p></div

The Eye Frequency of the Time Difference of Peak IOP Time Points Between Two Days.

<p>The Eye Frequency of the Time Difference of Peak IOP Time Points Between Two Days.</p

Parameters Values and ICCs of Diurnal IOP Curves in/Between Two Days.

<p>^a Data are expressed as mean ± SD;</p><p>^b P<0.05;</p><p>^c P<0.01.</p><p>Parameters Values and ICCs of Diurnal IOP Curves in/Between Two Days.</p

Mean IOP Values and ICCs at Each Time Point in/Between Two Days.

<p>^a Data are expressed as mean ± SD;</p><p>^b P<0.05;</p><p>^c P<0.01.</p><p>Mean IOP Values and ICCs at Each Time Point in/Between Two Days.</p

The Bland-Altman Plots for Different Parameters in OHT Group.

<p>The Bland-Altman Plots for Different Parameters in OHT Group.</p

Reactions of an Isolable Dialkylstannylene with Carbon Disulfide and Related Heterocumulenes

The reaction of isolable dialkylstannylene <b>1</b> with an excess amount of CS₂ produces an isomeric mixture of 3,3′-distanna-2,2′,4,4′-tetra­thia­bicyclo­butylidene <b>8</b> and 3,7-distanna-2,4,6,8-tetra­thia­bicyclo­[3.3.0]­oct-1(5)-ene <b>9</b> with a ratio depending on the reaction conditions. Compounds <b>8</b> and <b>9</b> are separated by column chromatography and characterized by NMR spectroscopy and X-ray crystallography. Detailed investigation of the reaction has revealed that the initial product is <b>8</b>, which isomerizes to <b>9</b> irreversibly under the catalytic influence of <b>1</b> as a Lewis acid. The above view is supported by the theoretical DFT calculations. Treatment of <b>1</b> with ArNCO [Ar = 2,6-<i>i</i>Pr₂C₆H₃] affords the corresponding carbamoyl­(hydroxyl)­stannane <b>11</b> via the hydrolysis of the corresponding sila­aziridinone formed by the [1 + 2] cycloaddition reaction of <b>1</b> with the NC double bond of the isocyanate. Stannylene <b>1</b> reacts with ArNCS, giving a mixture of complex products, while <b>1</b> does not react with CO₂

Twenty-Four-Hour IOP Curves in Two Days Described by Mean IOP Values at Different Time Points (Mean ± SD).

<p>Twenty-Four-Hour IOP Curves in Two Days Described by Mean IOP Values at Different Time Points (Mean ± SD).</p

Markov model tree.

<p>Markov model tree.</p