Penalized spline estimation for functional coefficient regression models

The functional coefficient regression models assume that the regression coefficients vary with some "threshold" variable, providing appreciable flexibility in capturing the underlying dynamics in data and avoiding the so-called "curse of dimensionality" in multivariate nonparametric estimation. We first investigate the estimation, inference, and forecasting for the functional coefficient regression models with dependent observations via penalized splines. The P-spline approach, as a direct ridge regression shrinkage type global smoothing method, is computationally efficient and stable. With established fixed-knot asymptotics, inference is readily available. Exact inference can be obtained for fixed smoothing parameter [lambda], which is most appealing for finite samples. Our penalized spline approach gives an explicit model expression, which also enables multi-step-ahead forecasting via simulations. Furthermore, we examine different methods of choosing the important smoothing parameter [lambda]: modified multi-fold cross-validation (MCV), generalized cross-validation (GCV), and an extension of empirical bias bandwidth selection (EBBS) to P-splines. In addition, we implement smoothing parameter selection using mixed model framework through restricted maximum likelihood (REML) for P-spline functional coefficient regression models with independent observations. The P-spline approach also easily allows different smoothness for different functional coefficients, which is enabled by assigning different penalty [lambda] accordingly. We demonstrate the proposed approach by both simulation examples and a real data application.

Genome-Wide Identification of the Long Noncoding RNAs of Tribolium castaneum in Response to Terpinen-4-ol Fumigation

Long noncoding RNAs (lncRNAs) are important regulatory factors in multiple biological processes, and several lncRNAs are known to respond to insecticides. However, the lncRNA functions that are associated with terpinen-4-ol resistance in the red flour beetle (Tribolium castaneum) have not yet been identified. In this study, we determined the differentially transcribed lncRNAs between fumigated and control experimental groups. In the six libraries that underwent RNA sequencing, 34,546 transcripts were identified, including 8267 novel lncRNAs, 4155 novel mRNAs, 1151 known lncRNAs, and 20,973 known mRNAs. Among these, we found that the expression of 1858 mRNAs and 1663 lncRNAs was significantly different in the fumigated group compared with the control group. Among the differentially transcribed lncRNAs, 453 were up-regulated and 1210 were down-regulated lncRNAs. In addition, we identified the regulatory function targets of the lncRNAs. Functionally, all lncRNAs and target genes associated with terpinen-4-ol metabolism were enriched in several metabolic pathways, like the ATP-binding cassette transporter, pentose interconversion, and glucuronate interconversion. To the best of our knowledge, this study represents the first global identification of lncRNAs and their potential association with terpinen-4-ol metabolism in the red flour beetle. These results will provide reference information for studies on the resistance to terpinen-4-ol and other essential oil compounds and chemical pesticides, as well as an understanding of other biological processes in T. castaneum

Repellency, Toxicity, Gene Expression Profiling and In Silico Studies to Explore Insecticidal Potential of <i>Melaleuca alternifolia</i> Essential Oil against <i>Myzus persicae</i>

In the current study, deterrent assay, contact bioassay, lethal concentration (LC) analysis and gene expression analysis were performed to reveal the repellent or insecticidal potential of M. alternifolia oil against M. persicae. M. alternifolia oil demonstrated an excellent deterrence index (0.8) at 2 g/L after 48 h. The oil demonstrated a pronounced contact mortality rate (72%) at a dose of 4 g/L after 24 h. Probit analysis was performed to estimate LC-values of M. alternifolia oil (40%) against M. persicae (LC30 = 0.115 g/L and LC50 = 0.37 g/L respectively) after 24 h. Furthermore, to probe changes in gene expression due to M. alternifolia oil contact in M. persicae, the expression of HSP 60, FPPS I, OSD, TOL and ANT genes were examined at doses of LC30 and LC50. Four out of the five selected genes&#8212;OSD, ANT, HSP 60 and FPPS I&#8212;showed upregulation at LC50, whereas, TOL gene showed maximum upregulation expression at LC30. Finally, the major components of M. alternifolia oil (terpinen-4-ol) were docked and MD simulated into the related proteins of the selected genes to explore ligand&#8315;protein modes of interactions and changes in gene expression. The results show that M. alternifolia oil has remarkable insecticidal and deterrent effects and also has the ability to affect the reproduction and development in M. persicae by binding to proteins

Thifluzamide, Fludioxonil, and Clothianidin as Seed Treatment Can Efficiently Control Major Soil-Borne Diseases, Aphids (Aphidoidea spp.), and Residue Distribution in the Field

Combined seed treatment with neonicotinoids and fungicides offers a potential control measure for pest management at the wheat seeding stage. In this study, a novel, highly-efficient seed-coating agent was prepared using thifluzamide, fludioxonil, and clothianidin as its active components and other additives (abbreviated to TFC). Laboratory experiments and field trials revealed a positive effect on germination, plant height, and root length, with 90% control efficiency on wheat sharp eyespots and aphid infestations. Meanwhile, the distribution of thifluzamide, fludioxonil, and clothianidin residues in the wheat plants at harvest was below 0.05 mg/kg both at the recommended dosage and at 2.0 times the recommended dose. Furthermore, an artificial soil assay of biotoxicity in earthworms revealed a low level of toxicity at LC50 &gt; 10 mg/kg. Overall, these findings suggest that TFC has the potential to control major soil-borne diseases and pest infestations in wheat, offering an environmentally-friendly alternative to more toxic pesticides

The Effect of Neonicotinoid Insecticide and Fungicide on Sugar Responsiveness and Orientation Behavior of Honey Bee (Apis mellifera) in Semi-Field Conditions

Neonicotinoid insecticides are in widespread use around the world, cause pollinator decline. We used semi-field conditions to determine the effect of sublethal insecticide, thiamethoxam, exposure on orientation behavior and sugar responsiveness. Bees could not reject the non-treated flower or the insecticide or insecticide/fungicide treated flower. After bees consumed the insecticide or insecticide/fungicide treated nectar, they could not discriminate between a flower odor or blank control in a Y-maze when making a first choice. We also found that treated bees wander back and forth in both arms to make a final decision about food location, and used longer duration in the Y maze than the control group. Sugar responsiveness was also reduced after bees were fed with insecticide or insecticide/fungicide treated food, one week was needed for them to display the same level of responsiveness as the control group. The thiamethoxam or thiamethoxam/carbendazol treated crop field does not act as an olfactory repellent to the bee, but it does affect its post-consumption behavior

Apilactobacillus kunkeei Alleviated Toxicity of Acetamiprid in Honeybee

Nowadays, colony collapse disorder extensively affects honeybees. Insecticides, including acetamiprid, are considered as critical factors. As prevalent probiotics, we speculated that supplementation with lactic acid bacteria (LAB) could alleviate acetamiprid-induced health injuries in honeybees. Apilactobacillus kunkeei was isolated from beebread; it significantly increased the survival of honeybees under acetamiprid exportation (from 84% to 92%). Based on 16S rRNA pyrosequencing, information on the intestinal bacteria of honeybees was acquired. The results showed that supplementation with A. kunkeei significantly increased survival and decreased pollen consumption by honeybees under acetamiprid exportation. Under acetamiprid exportation, some opportunistic and pathogenic bacteria invaded the intestinal regions. Subsequently, the community richness and diversity of symbiotic microbiota were decreased. The community structure of intestinal bacteria was changed and differentiated. However, with the supplementation of A. kunkeei, the community richness and community diversity of symbiotic microbiota showed an upward trend, and the community structure was stabilized. Our results showed that A. kunkeei alleviated acetamiprid-induced symbiotic microbiota dysregulation and mortality in honeybees. This demonstrates the importance of symbiotic microbiota in honeybees and supports the application of Apilactobacillus kunkeei as probiotics in beekeeping

Residue Dynamics and Risk Assessment of Prochloraz and Its Metabolite 2,4,6-Trichlorophenol in Apple

The residue dynamics and risk assessment of prochloraz and its metabolite 2,4,6-trichlorophenol (2,4,6-TCP) in apple under different treatment concentrations were investigated using a GC-ECD method. The derivatization percent of prochloraz to 2,4,6-TCP was stable and complete. The recoveries of prochloraz and 2,4,6-TCP were 82.9%–114.4%, and the coefficients of variation (CV) were 0.7%–8.6% for the whole fruit, apple pulp, and apple peel samples. Under the application of 2 °C 2.0 g/L, 2 °C 1.0 g/L, 20 °C 2.0 g/L, and 20 °C 1.0 g/L treatment, the half-life for the degradation of prochloraz was 57.8–86.6 d in the whole fruit and apple peel, and the prochloraz concentration in the apple pulp increased gradually until a peak (0.72 mg·kg−1) was reached. The concentration of 2,4,6-TCP was below 0.1 mg·kg−1 in four treatment conditions and not detected (&lt;LOD) in apple pulp. Finally, based on the detection of market samples in Hefei (China), we believe that the residual level of prochloraz in apples meets the requirements of the Chinese standards

Molecular Basis of Resistance to Bensulfuron-Methyl in a Smallflower Umbrella Sedge (<i>Cyperus difformis</i> L.) Population from China

Smallflower umbrella sedge (Cyperus difformis L.) is an invasive weed, and infestations of C. difformis are increasing in rice (Oryza sativa L.) fields in China. Bensulfuron-methyl is a widely used sulfonylurea herbicide that inhibits the acetolactate synthase (ALS) enzyme and has been used in recent years for effectively controlling annual weeds in the Cyperaceae family. In this study, a suspected resistant population of C. difformis (BBHY1) was collected from a rice field in Huaiyuan County, Anhui Province, China, that survived treatment with bensulfuron-methyl at the field-recommended rate (FRR). Single-dose tests and whole-plant bioassays confirmed that the BBHY1 population was resistant to bensulfuron-methyl and had evolved a high level of resistance, with a resistance index (RI) of 12.87. Sequencing of the ALS gene revealed a CCT to CAT point mutation at codon 197, which caused a P-to-H substitution in the resistant plants. Analysis of the relative expression of ALS revealed no significant differences between the resistant and susceptible populations. Inhibiting the activity of cytochrome P450s (P450s) or glutathione S-transferases (GSTs) had no significant effect on bensulfuron-methyl resistance. The BBHY1 population exhibited cross-resistance to pyrazosulfuron-ethyl, penoxsulam, and bispyribac-sodium, with RIs ranging from 5.48 to 20.63, but remained susceptible to MCPA sodium, florpyrauxifen-benzyl, and bentazon, with RIs of <1.00. These herbicides could be potentially used as alternatives for controlling resistant populations and managing herbicide resistance in other aggressive weeds in rice fields

Evaluation of Highly Detectable Pesticides Sprayed in Brassica napus L.: Degradation Behavior and Risk Assessment for Honeybees

Honeybees are major pollinators of agricultural crops and many other plants in natural ecosystems alike. In recent years, managed honeybee colonies have decreased rapidly. The application of pesticides is hypothesized to be an important route leading to colony loss. Herein, a quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was used to determine eight highly detectable pesticides (carbendazim, prochloraz, pyrimethanil, fenpropathrin, chlorpyrifos, imidacloprid, thiamethoxam, and acetamiprid) in rape flowers. A field experiment was conducted at the recommended dose to evaluate the contact exposure risk posed to honeybees for 0&ndash;14 days after treatment. The initial residue deposits of neonicotinoids and fungicides among these compounds were 0.4&ndash;1.3 mg/kg and 11.7&ndash;32.3 mg/kg, respectively, and 6.4 mg/kg for fenpropathrin and 4.2 mg/kg for chlorpyrifos. The risk was quantified using the flower hazard quotient (FHQ) value. According to the data, we considered imidacloprid, thiamethoxam, chlorpyrifos, fenpropathrin, and prochloraz to pose an unacceptable risk to honeybees after spraying in fields, while fungicides (carbendazim and pyrimethanil) and acetamiprid posed moderate or acceptable risks to honeybees. Therefore, acetamiprid can be used instead of imidacloprid and thiamethoxam to protect rape from some insects in agriculture, and the application of prochloraz should be reduced