Spraying double-stranded RNA targets UDP-N-acetylglucosamine pyrophosphorylase in the control of Nilaparvata lugens.

The rice pest Nilaparvata lugens (the brown planthopper, BPH) has developed different levels of resistance to at least 11 chemical pesticides. RNAi technology has contributed to the development of environmentally friendly RNA biopesticides designed to reduce chemical use. Consequently, more precise targets need to be identified and characterized, and efficient dsRNA delivery methods are necessary for effective field pest control. In this study, a low off-target risk dsNlUAP fragment (166 bp) was designed in silico to minimize the potential adverse effects on non-target organisms. Knockdown of NlUAP via microinjection significantly decreased the content of UDP-N-acetylglucosamine and chitin, causing chitinous structural disorder and abnormal phenotypes in wing and body wall, reduced fertility, and resulted in pest mortality up to 100 %. Furthermore, dsNlUAP was loaded with ROPE@C, a chitosan-modified nanomaterial for spray application, which significantly downregulated the expression of NlUAP, led to 48.9 % pest mortality, and was confirmed to have no adverse effects on Cyrtorhinus lividipennis, an important natural enemy of BPH. These findings will contribute to the development of safer biopesticides for the control of N. lugens.

Functional analysis of Ornithine decarboxylase in manipulating the wing dimorphism in Nilaparvata lugens (Stål) (Hemiptera: Delphacidae).

The brown planthopper (BPH, Nilaparvata lugens), a major insect pest of rice, can make a shift in wing dimorphism to adapt to complex external environments. Our previous study showed that NlODC (Ornithine decarboxylase in N. lugens) was involved in wing dimorphism of the brown planthopper. Here, further experiments were conducted to reveal possible molecular mechanism of NlODC in manipulating the wing dimorphism. We found that the long-winged rate (LWR) of BPH was significantly reduced after RNAi of NlODC or injection of DFMO (D, L-α-Difluoromethylornithine), and LWR of males and females significantly decreased by 21.7% and 34.6%, respectively. Meanwhile, we also examined the contents of three polyamines under DFMO treatment and found that the contents of putrescine and spermidine were significantly lower compared to the control. After 3rd instar nymphs were injected with putrescine and spermidine, LWR was increased significantly in both cases, and putrescine was a little bit more effective, with 5.6% increase in males and 11.4% in females. Three days after injection of dsNlODC, injection of putrescine and spermidine rescued LWR to the normal levels. In the regulation of wing differentiation in BPH, NlODC mutually antagonistic to NlAkt may act through other signaling pathways rather than the classical insulin signaling pathway. This study illuminated a physiological function of an ODC gene involved in wing differentiation in insects, which could be a potential target for pest control.

Polyacrylic Acid Hydrogel Coating for Underwater Adhesion: Preparation and Characterization.

Underwater adhesion involves bonding substrates in aqueous environments or wet surfaces, with applications in wound dressing, underwater repairs, and underwater soft robotics. In this study, we investigate the underwater adhesion properties of a polyacrylic acid hydrogel coated substrate. The underwater adhesion is facilitated through hydrogen bonds formed at the interface. Our experimental results, obtained through probe-pull tests, demonstrate that the underwater adhesion is rapid and remains unaffected by contact pressure and pH levels ranging from 2.5 to 7.0. However, it shows a slight increase with a larger adhesion area. Additionally, we simulate the debonding process and observe that the high-stress region originates from the outermost bonding region and propagates towards the center, spanning the thickness of the target substrate. Furthermore, we showcase the potential of using the underwater adhesive hydrogel coating to achieve in-situ underwater bonding between a flexible electronic demonstration device and a hydrogel contact lens. This work highlights the advantages of employing hydrogel coatings in underwater adhesion applications and serves as inspiration for the advancement of underwater adhesive hydrogel coatings capable of interacting with a wide range of substrates through diverse chemical and physical interactions at the interface.

Effects of Pre-Curing on the Structure and Properties of Paper-Based Materials.

Paper-based friction material is a typical paper-based composite that is usually cured via hot-pressing. This curing method does not account for the effect of pressure on the matrix resin, resulting in uneven distribution of resin in the material and reducing the mechanical properties of friction materials. To overcome the above shortcomings, a pre-curing method was introduced before hot-pressing, and the effects of different pre-curing degrees on the surface morphology and mechanical properties of paper-based friction materials were studied. The pre-curing degree significantly affected the resin distribution and interfacial bonding strength of the paper-based friction material. When the material was cured at 160 °C for 10 min, the pre-curing degree reached 60%. At this point, most of the resin was in a gel state, which could retain abundant pore structures on the material surface without causing mechanical damage to the fiber and resin matrix during hot-pressing. Ultimately, the paper-based friction material exhibited improved static mechanical properties, decreased permanent deformation, and reasonable dynamic mechanical properties.

Fabrication and Experimental Study of Micro/Sub-Micro Porous Copper Coating for Anti-Icing Application.

Micro and sub-micro-spherical copper powder slurries were elaborately prepared to fabricate different types of porous coating surfaces. These surfaces were further treated with low surface energy modification to obtain the superhydrophobic and slippery capacity. The surface wettability and chemical component were measured. The results showed that both the micro and sub-micro porous coating layer greatly increased the water-repellence capability of the substrate compared with the bare copper plate. Notably, the PFDTES-fluorinated coating surfaces yielded superhydrophobic ability against water under 0 °C with a contact angle of ~150° and a contact angle of hysteresis of ~7°. The contact angle results showed that the water repellency of the coating surface deteriorated with decreasing temperature from 10 °C to -20 °C, and the reason was probably recognized as the vapor condensation in the sub-cooled porous layer. The anti-icing test showed that the ice adhesion strengths of the micro and sub-micro-coated surfaces were 38.5 kPa and 30.2 kPa, producing a 62.8% and 72.7% decrease compared to the bare plate. The PFDTES-fluorinated and slippery liquid-infused porous coating surfaces both produced ultra-low ice adhesion strengths of 11.5-15.7 kPa compared with the other non-treated surfaces, which showed prominent properties for anti-icing and deicing requirement of the metallic surface.

[Adaptive evolution of microorganisms based on industrial environmental perturbations].

The development of synthetic biology has greatly promoted the construction of microbial cell factories, providing an important strategy for green and efficient chemical production. However, the bottleneck of poor tolerance to harsh industrial environments has become the key factor hampering the productivity of microbial cells. Adaptive evolution is an important method to domesticate microorganisms for a certain period by applying targeted selection pressure to obtain desired phenotypic or physiological properties that are adapted to a specific environment. Recently, with the development of technologies such as microfluidics, biosensors, and omics analysis, adaptive evolution has laid the foundation for efficient productivity of microbial cell factories. Herein, we discuss the key technologies of adaptive evolution and their important applications in improvement of environmental tolerance and production efficiency of microbial cell factories. Moreover, we looked forward to the prospects of adaptive evolution to realize industrial production by microbial cell factories.

Comparison of the signaling pathways of wing dimorphism regulated by biotic and abiotic stress in the brown planthopper.

Wing polymorphism is an evolutionary trait that is widely present in various insects and provides a model system for studying the evolutionary significance of insect dispersal. The brown planthopper (BPH, Nilaparvata lugens) can alter its wing morphs under biotic and abiotic stress. However, whether differential signaling pathways are induced by the 2 types of stress remain largely unknown. Here, we screened a number of candidate genes through weighted gene co-expression network analysis (WGCNA) and found that ornithine decarboxylase (NlODC), a key enzyme in the synthesis of polyamines, was associated with wing differentiation in BPH and mainly responded to abiotic stress stimuli. We analyzed the Kyoto Encyclopedia of Genes and Genomes enrichment pathways of differentially expressed genes under the 2 stresses by transcriptomic comparison, and found that biotic stress mainly influenced insulin-related signaling pathways while abiotic stress mainly influenced hormone-related pathways. Moreover, we found that insulin receptor 1 (NlInR1) may regulate wing differentiation of BPH by responding to both biotic and abiotic stress, but NlInR2 only responded to biotic stress. Similarly, the juvenile hormone epoxide hydrolase associated with juvenile hormone degradation and NlODC may regulate wing differentiation mainly through abiotic stress. A model based on the genes and stresses to modulate the wing dimorphism of BPH was proposed. These findings present a comprehensive molecular mechanism for wing polymorphism in BPH induced by biotic and abiotic stress.

[Application of personalized digital analog assisted acetabular prosthesis precise implantation in Crowe typeâ and â ¡ hip dysplasia].

OBJECTIVE: To explore the effect of personalized digital analog assisted acetabular prosthesis precise implantation in hip dysplasia. METHODS: From February 2017 to July 2019, 11 patients(12 hips) with hip dysplasia underwent total hip arthroplasty, including 4 males(5 hips) and 7 females(7 hips), aged from 27 to 61 years old, with an average of (46.64±12.93) years old;Crowe classification:8 hips in typeⅠ and 4 hips in typeⅡ. The preoperative thin-layer CT scan was imported into Mimics 10.01 software. The appropriate size and placement angle of acetabular prosthesis were selected through preoperative simulation, and the acetabular bone defect was understood to determine whether structural bone grafting was needed during the operation. The length of both lower limbs, the anteversion angle of acetabular prosthesis, the abduction angle, the height of acetabular rotation center and the horizontal distance of hip joint center before and after the operation were measured, and the postoperative dislocation, bone graft healing and acetabular cup loosening were observed. The hip Harris score was used to evaluate the joint function. RESULTS: All patients were followed up for 18 to 30 months with an average of (23.45±3.70) months. There was no prosthesis dislocation, loosening and bone graft healing after operation. One case had numbness in the innervation area due to the traction of sciatic nerve during operation, and was treated with neurotrophic drugs and recovered one month after operation. The length difference of both lower limbs decreased from (31.73±5.98) mm before operation to (4.73±1.90) mm 3 months after operation (t=15.268, P<0.01). The anteversion angle of acetabular cup and acetabulum was (17.45±3.62)°and abduction angle was (40.10 ± 2.30)° after operation. In all cases, the abduction angle and anteversion angle were within the safe range of Lewinek. The height of hip rotation center was (20.64±2.58) mm and the horizontal inward displacement of hip was (33.46±3.61) mm. Harris score increased from (45.36±2.34) before operation to (91.27±2.37) 3 months after operation (P<0.05). CONCLUSION: Through preoperative personalized digital analog reconstruction of acetabulum in patients with hip dysplasia, we can better understand the acetabular defect, help to evaluate the size and placement angle of acetabular prosthesis and whether structural bone grafting is needed, and obtain satisfactory clinical curative effect.

SMC4 enhances the chemoresistance of hepatoma cells by promoting autophagy.

Background: Drug resistance is a major contributing factor to chemotherapy failure in hepatocellular carcinoma (HCC) patients. However, the exact mechanism underlying the chemoresistance of HCC remains unknown. Methods: HepG2 cells were incubated with different concentrations of 5-fluorouracil (5-FU), and the Cell Counting Kit-8 assay was used to test the cell survival rate. The expression level of structural maintenance of chromosome 4 (SMC4) in drug-resistant cells was analyzed by real-time quantitative polymerase chain reaction (PCR) and western blotting. To assess autophagy, immunofluorescence was applied to detect the light chain 3 beta (LC3B) level in HepG2/5-FU cells. To further study the upstream regulation of miR (microRNA)-219/SMC4, a gene chip assay was performed. A luciferase reporter assay was used to determine whether long non-coding RNA-XIST (lncRNA-XIST) functions as a competitive endogenous RNA (ceRNA) for miR-219. Cellular proliferation was evaluated using MTT [3-(4,5)-dimethylthiahiazo (-z-y1)-2,5-di-phenytetrazoliumromide] and colony formation assays, wound healing and invasion assays were performed to study the invasion and migration ability of the cells, and flow cytometry assays were carried out to evaluate cell apoptosis. Results: In the present study, we established a drug-resistant hepatoma cell line named HepG2/5-FU. We confirmed that SMC4 may play an important role in hepatoma cell autophagy and could promote autophagy to increase the drug resistance of hepatoma cells. We also demonstrated that lncRNA-XIST may competitively bind to miR-219 by acting as a miRNA sponge, thereby preventing miR-219 from effectively reducing the expression of SMC4 and further affecting the autophagy and drug resistance of hepatoma cells via the adenosine 5'-monophosphate (AMP)-activated protein kinase/mechanistic target of rapamycin (AMPK/mTOR) pathway. Conclusions: Our study suggests that SMC4 may be a potential marker of a poor HCC response to chemotherapy and a novel therapeutic target for HCC chemotherapy.

High-Dimensional Precision Medicine From Patient-Derived Xenografts.

The complexity of human cancer often results in significant heterogeneity in response to treatment. Precision medicine offers the potential to improve patient outcomes by leveraging this heterogeneity. Individualized treatment rules (ITRs) formalize precision medicine as maps from the patient covariate space into the space of allowable treatments. The optimal ITR is that which maximizes the mean of a clinical outcome in a population of interest. Patient-derived xenograft (PDX) studies permit the evaluation of multiple treatments within a single tumor, and thus are ideally suited for estimating optimal ITRs. PDX data are characterized by correlated outcomes, a high-dimensional feature space, and a large number of treatments. Here we explore machine learning methods for estimating optimal ITRs from PDX data. We analyze data from a large PDX study to identify biomarkers that are informative for developing personalized treatment recommendations in multiple cancers. We estimate optimal ITRs using regression-based (Q-learning) and direct-search methods (outcome weighted learning). Finally, we implement a superlearner approach to combine multiple estimated ITRs and show that the resulting ITR performs better than any of the input ITRs, mitigating uncertainty regarding user choice. Our results indicate that PDX data are a valuable resource for developing individualized treatment strategies in oncology. Supplementary materials for this article are available online.

CRISPR/Cas9-mediated knockout of the NlCSAD gene results in darker cuticle pigmentation and a reduction in female fecundity in Nilaparvata lugens (Hemiptera: Delphacidae).

In insects, cuticular pigmentation genes have been exploited as potential visible markers for constructing genetic manipulation systems. Here, we cloned cysteine sulfinic acid decarboxylase (CSAD), an orthologue of melanin metabolism pathway genes, and performed RNAi experiments in the brown planthopper Nilaparvata lugens (Hemiptera: Delphacidae). The results showed that a decrease in the level of transcription of NlCSAD increased melanin deposition in the body compared to the control group, resulting in darker cuticle pigmentation. Female adults treated with dsNlCSAD and mated with wild-type males laid significantly fewer eggs than the dsGFP-treated group, and lower hatchability of the eggs was also observed. In addition, two melanic mutant N. lugens strains (NlCSAD-/+ and NlCSAD-/-) constructed by the CRISPR/Cas9 genome editing system showed darker cuticular melanisation and a reduced oviposition and hatching rate, but the homozygotes had a darker body colour, fewer eggs and lower hatchability than heterozygotes or individuals after RNAi. Thus, we have provided the first evidence that NlCSAD is required for normal body pigmentation in adults and has a role in the fecundity of females and hatchability of eggs in N. lugens via a combination of RNAi and knockout of target genes based on the CRISPR/Cas9 genome editing system. Our results suggest that NlCSAD is a candidate visual reference gene for genetic manipulation of this important crop pest.

Identifying Heterogeneous Effect using Latent Supervised Clustering with Adaptive Fusion.

Precision medicine is an important area of research with the goal of identifying the optimal treatment for each individual patient. In the literature, various methods are proposed to divide the population into subgroups according to the heterogeneous effects of individuals. In this paper, a new exploratory machine learning tool, named latent supervised clustering, is proposed to identify the heterogeneous subpopulations. In particular, we formulate the problem as a regression problem with subject specific coefficients, and use adaptive fusion to cluster the coefficients into subpopulations. This method has two main advantages. First, it relies on little prior knowledge and weak parametric assumptions on the underlying subpopulation structure. Second, it makes use of the outcome-predictor relationship, and hence can have competitive estimation and prediction accuracy. To estimate the parameters, we design a highly efficient accelerated proximal gradient algorithm which guarantees convergence at a competitive rate. Numerical studies show that the proposed method has competitive estimation and prediction accuracy, and can also produce interpretable clustering results for the underlying heterogeneous effect.

Multicategory Outcome Weighted Margin-based Learning for Estimating Individualized Treatment Rules.

Due to heterogeneity for many chronic diseases, precise personalized medicine, also known as precision medicine, has drawn increasing attentions in the scientific community. One main goal of precision medicine is to develop the most effective tailored therapy for each individual patient. To that end, one needs to incorporate individual characteristics to detect a proper individual treatment rule (ITR), by which suitable decisions on treatment assignments can be made to optimize patients' clinical outcome. For binary treatment settings, outcome weighted learning (OWL) and several of its variations have been proposed recently to estimate the ITR by optimizing the conditional expected outcome given patients' information. However, for multiple treatment scenarios, it remains unclear how to use OWL effectively. It can be shown that some direct extensions of OWL for multiple treatments, such as one-versus-one and one-versus-rest methods, can yield suboptimal performance. In this paper, we propose a new learning method, named Multicategory Outcome weighted Margin-based Learning (MOML), for estimating ITR with multiple treatments. Our proposed method is very general and covers OWL as a special case. We show Fisher consistency for the estimated ITR, and establish convergence rate properties. Variable selection using the sparse l 1 penalty is also considered. Analysis of simulated examples and a type 2 diabetes mellitus observational study are used to demonstrate competitive performance of the proposed method.

RNA interference of a trehalose-6-phosphate synthase gene reveals its roles in the biosynthesis of chitin and lipids in Heortia vitessoides (Lepidoptera: Crambidae).

Trehalose-6-phosphate synthase (TPS), an enzyme that hydrolyzes two glucose molecules to yield trehalose, plays a pivotal role in various physiological processes. In this study, we cloned the trehalose-6-phosphate synthase gene (HvTPS) and investigated its expression patterns in various tissues and developmental stages in Heortia vitessoides Moore (Lepidoptera: Crambidae). HvTPS was highly expressed in the fat body and after pupation or before molting. We knocked down TPS in H. vitessoides by RNA interference and found that 3.0 µg of dsHvTPS resulted in optimal interference at 24 h and 36 h post-injection and caused a sharp decline in the survival rate during the 5th instar larval-pupal stage and obviously abnormal or lethal phenotypes. Additionally, compared to the controls, TPS activity and trehalose contents were significantly lower and the glucose content was significantly higher 24 h or 36 h after injection with 3.0 µg of dsHvTPS. Furthermore, the silencing of HvTPS suppressed the expression of six key genes in the chitin biosynthesis pathway and one key gene related to lipid catabolism. The expression levels of two genes associated with lipid biosynthesis were upregulated. These results strongly suggest that HvTPS is essential for the normal growth and development of H. vitessoides and provide a reference for further studies of the utility of key genes involved in chitin and lipid biosynthesis for controlling insect development.

Suppression of Gene Juvenile Hormone Diol Kinase Delays Pupation in Heortia vitessoides Moore.

Juvenile hormone diol kinase (JHDK) is a critical enzyme involved in juvenile hormone degradation in insects. In this study, HvJHDK in the Heortia vitessoides Moore (Lepidoptera: Crambidae) transcriptional library was cloned. Stage-specific expression patterns of HvJHDK, HvJHEH, and HvJHE as well as juvenile hormone titers were determined. The three tested enzymes participated in juvenile hormone degradation. Moreover, juvenile hormone titers peaked after larval-larval molts, consistent with a role for juvenile hormone in inhibition of metamorphosis. HvJHDK was subsequently suppressed using RNA interference (RNAi) to reveal its functions. Different concentrations of dsJHDK elicited the optimal interference efficiency at different life stages of H. vitessoides. Suppression of HvJHDK decreased HvJHDK content and increased the juvenile hormone titer, thereby resulting in reduced triglyceride content, sharply declined survival rate, clearly lethal phenotypes, and extended larval growth. Moreover, suppression of HvJHDK upregulated HvJHEH and HvJHE expression levels, suggesting that there is feedback regulation in the juvenile hormone metabolic pathway. Taken together, our findings provide molecular references for the selection of novel insecticidal targets.

Chitin deacetylase 1 and 2 are indispensable for larval-pupal and pupal-adult molts in Heortia vitessoides (Lepidoptera: Crambidae).

Heortia vitessoides Moore is a notorious defoliator of Aquilaria sinensis (Lour.) Gilg trees. Chitin deacetylases (CDAs) catalyze the N-deacetylation of chitin, which is a crucial process for chitin modification. Here, we identified and characterized HvCDA1 and HvCDA2 from H. vitessoides. HvCDA1 and HvCDA2 possess typical domain structures of CDAs and belong to the Group I CDAs. HvCDA1 and HvCDA2 were highly expressed before and after the larval-larval molt. In addition, both exhibited relatively high mRNA expression levels during the larval-pupal molt, the pupal stage, and the pupal-adult molt. HvCDA1 and HvCDA2 transcript expression levels were highest in the body wall and relatively high in the larval head. Significant increases in the HvCDA1 and HvCDA2 transcript expression levels were observed in the larvae upon exposure to 20-hydroxyecdysone. RNA interference-mediated HvCDA1 and HvCDA2 silencing significantly inhibited HvCDA1 and HvCDA2 expression, with abnormal or nonviable phenotypes being observed. Post injection survival rates of the larvae injected with dsHvCDA1 and dsHvCDA2 were 66.7% and 46.7% (larval-pupal) during development and 23.0% and 6.7% (pupal-adult), respectively. These rates were significantly lower than those of the control group insects. Our results suggest that HvCDA1 and HvCDA2 play important roles in the larval-pupal and pupal-adult transitions and represent potential targets for the management of H. vitessoides.

Knockdown of ß-N-acetylglucosaminidase gene disrupts molting process in Heortia vitessoides Moore.

ß-N-acetylglucosaminidase (NAG) is a key enzyme in insect chitin metabolism and plays an important role in many physiological activities of insects. The HvNAG1 gene was identified from the Heortia vitessoides Moore (Lepidoptera: Crambidae) cDNA library and its expression patterns were determined using quantitative real-time polymerase chain reaction. The results indicated that HvNAG1 mRNA levels were high in the midgut and before molting, and 20E could induce its expression. Subsequently, the HvNAG1 gene was knocked down via RNA interference to identify its functions. We found that 3 µg of dsNAG1 resulted in optimal interference at 48 and 72 hr after injection, causing a decrease in NAG1 protein content, which resulted in abnormal or lethal phenotypes, and a sharp decrease in the survival rate. These results indicate that HvNAG1 plays a key role in the molting process of H. vitessoides. However, the silencing of HvNAG1 had no significant effect on the chitin metabolism-related genes tested in this study. Our present study provides a reference for further research on the utility of key genes involved in the chitin metabolic pathway in the insect molting process.

Candidate olfactory genes identified in Heortia vitessoides (Lepidoptera: Crambidae) by antennal transcriptome analysis.

Heortia vitessoides Moore is the most severe defoliating pest of Aquilaria sinensis (Lour.) Gilg (Thymelaeaceae) forests. Olfaction in insects is essential for host identification, mating, and oviposition, in which olfactory proteins, including odorant-binding proteins (OBPs), chemosensory proteins (CSPs), olfactory receptors (ORs), ionotropic receptors (IRs), and sensory neuron membrane proteins (SNMPs), are responsible for chemical signaling. Here, we determined the transcriptomes of male and female adult antennae of H. vitessoides. We assembled 52,383 unigenes and annotated their putative gene functions based on the gene ontology (GO), eukaryotic ortholog groups (KOG), and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Overall, 61 olfactory-related transcripts, including nine OBPs, 10 CSPs, 28 ORs, 12 IRs, and two SNMPs, were identified. Expression patterns of OBPs and CSPs in the female antennae, male antennae, and legs were performed using reverse transcription quantitative PCR (RT-qPCR). The results revealed that HvitOBP1, HvitOBP6, and HvitGOBP1 were enriched in the female antennae, while HvitOBP2, HvitOBP3, HvitOBP5, HvitGOBP2, and HvitPBP1 were enriched in the male antennae. HvitOBP4 was expressed at nearly the same level in the antennae of both males and females. Four CSPs (HvitCSP3, HvitCSP5, HvitCSP7, and HvitCSP10) and two CSPs (HvitCSP1 and HvitCSP4) were expressed at higher levels in the female and male antennae, respectively. HvitCSP6 was expressed at higher levels both in the female antennae and legs. Three CSP genes (HvitCSP2, HvitCSP8, and HvitCSP9) were expressed at higher levels in the legs. These results provide a basis for further studies on the molecular olfactory mechanisms of H. vitessoides.

Identification and characterization of the catalase gene involved in resistance to thermal stress in Heortia vitessoides using RNA interference.

To elucidate the role of catalase (CAT) in Heortia vitessoides Moore, which is one of the most destructive defoliating pests in Aquilaria sinensis (Loureiro) Sprenger forests, a CAT gene (HvCAT) was identified in the transcriptome of adult H. vitessoides. Sequence analyses indicated that HvCAT encodes a protein containing 507 amino acids, including a proximal active site sequence (FXRERIPERVVHAKGXGA), heme-ligand sequence (RLFSYNDTX), heme-binding residues (H73, S112, N146, F151, F159, R352, and Y356), and NADPH-binding residues (P149, H192, Y196, G199, R201, N211, H233, K235, I300, W301, P302, H303, Q442, and L445). A phylogenetic analysis indicated that CAT from lepidopteran species could be assigned to one well-supported cluster. Regarding its stage- and tissue-specific expression profiles, HvCAT was expressed at high levels in fifth-instar larvae, fat body of larvae, and abdomen of adults. Furthermore, when fifth-instar larvae were exposed to thermal stress at 35, 37, and 39 °C, hydrogen peroxide and malondialdehyde content significantly increased. HvCAT mRNA was upregulated when the larvae were exposed to temperatures of 31, 33, 35, 37, and 39 °C. The enzymatic activity of HvCAT was significantly elevated following thermal stress (35 and 37 °C). After the knockdown of HvCAT by double-stranded RNA interference, the expression of thioredoxin peroxidase (Tpx) increased, whereas that of copper zinc superoxide dismutase (Cu/ZnSOD) decreased. Additionally, knocking down HvCAT transcripts in fifth-instar larvae resulted in accelerated death following thermal stress at 35 °C. In summary, the results suggest that HvCAT plays a major role in the thermotolerance of H. vitessoides.

Double Sparsity Kernel Learning with Automatic Variable Selection and Data Extraction.

Learning in the Reproducing Kernel Hilbert Space (RKHS) has been widely used in many scientific disciplines. Because a RKHS can be very flexible, it is common to impose a regularization term in the optimization to prevent overfitting. Standard RKHS learning employs the squared norm penalty of the learning function. Despite its success, many challenges remain. In particular, one cannot directly use the squared norm penalty for variable selection or data extraction. Therefore, when there exists noise predictors, or the underlying function has a sparse representation in the dual space, the performance of standard RKHS learning can be suboptimal. In the literature, work has been proposed on how to perform variable selection in RKHS learning, and a data sparsity constraint was considered for data extraction. However, how to learn in a RKHS with both variable selection and data extraction simultaneously remains unclear. In this paper, we propose a unified RKHS learning method, namely, DOuble Sparsity Kernel (DOSK) learning, to overcome this challenge. An efficient algorithm is provided to solve the corresponding optimization problem. We prove that under certain conditions, our new method can asymptotically achieve variable selection consistency. Simulated and real data results demonstrate that DOSK is highly competitive among existing approaches for RKHS learning.