Search

Abstract Brown marmorated stink bug (BMSB), Halyomorpha halys (Stål) (Hemiptera: Penta-tomidae), is a highly polyphagous and invasive insect pest with more than 300 plant species as hosts, including a wide range of economic crops. To date, several egg parasitoid species are reported to attack BMSB. In this study, two species of Trissolcus (Hymenoptera: Platygastridae) and one Anastatus (Hymenoptera: Eupelmidae) were recovered from field exposed BMSB sentinel eggs in Beijing, China. The wasps’ small size of only 1.5 mm and 4 mm in length make them difficult to identify morphologically and required taxonomist for identification of specific species. In addition, these parasitoids have morphology sibling species and have been misidentified several times in China. To overcome these problems, a molecular method with species-specific primers designed for the COI gene has been developed to identify Trissolcus, Anastatus and their host samples from field collected samples. After successful morphological confirmation with experts, DNA extractions were carried out from these samples. PCR amplification using published primers for T. japonicus, A. japonicus and BMSB specimens confirmed the species. As for T. cultratus, species specific primers TCYF and TCYR were developed which produce 340-bp PCR products length while no positive amplifications found in other wasps and host. Sensitivity analysis of markers revealed that TCYF and TCYR primers could detect as low a DNA template concentration as 0.00025 ng/μL. This indicates that PCR with these primers specifically and sensitively differentiates T. cultratus specimens from other similar wasp species. All the primers tested in this study could discriminate between parasitized and non-parasitized BMSB eggs. This molecular identification method shows promise for conveniently identifying Trissolcus and Anastatus species in host-parasitoid associations and accurately evaluating parasitism rates in the field.

The olfactory system of insects is crucial in modulating behaviors such as host seeking, mating, and oviposition. Odorant-binding proteins (OBPs) are involved in semiochemical recognition. OBPs recognize and bind odorants and transport them to odorant receptors located in olfactory neurons. Harmonia axyridis (Coleoptera: Coccinellidae) is a widely used predacious biological control agent for many agricultural and forestry pests. This study identified 19 OBPs in H. axyridis based on the antennal and whole-body transcriptomes of adults and obtained all the full-length open reading frames, including 11 ‘Classic’ OBPs, 7 ‘Minus-C’ OBPs and 1 ‘Plus-C’ OBP. They encoded 125 to 241 amino acid proteins with molecular weights ranging from 13.75 to 27.75 kDa and isoelectric points ranging from 4.15 to 8.80. Phylogenetic analyses were used to study the relationships between H. axyridis OBPs and OBPs from other species of Coleoptera. Quantitative real-time PCR (qPCR) analysis showed that HaxyOBP2, 3, 5, 8, 10, 12, 13, 14, and 15 were highly expressed in antennae of both adult females and males. Moreover, HaxyOBP2, 3, 5, 12, and 15 were more abundantly expressed in antennae than other body parts, while HaxyOBP13 and HaxyOBP14 were expressed predominantly, and at similar levels, in the head and antennae. The other OBP genes were highly expressed in non-olfactory tissues including the thorax, abdomen, legs, and wings. These results provide valuable information for further study of H. axyridis olfaction, which may ultimately enhance its use as a biocontrol agent.

Harmonia axyridis is an important natural enemy that consumes many agricultural and forestry pests. It relies on a sensitive olfactory system to find prey and mates. Odorant-binding proteins (OBPs) as the first-step of recognizing volatiles, transport odors through sensillum lymph to odorant receptors (ORs). However, little is known about the molecular mechanisms of H. axyridis olfaction. In this study, four H. axyridis antenna specific OBP genes, HaxyOBP3, 5, 12, and 15, were bacterially expressed and the binding features of the four recombinant proteins to 40 substances were investigated using fluorescence competitive binding assays. Three-dimensional structure modeling and molecular docking analysis predicted the binding sites between HaxyOBPs and candidate volatiles. Developmental expression analyses showed that the four HaxyOBP genes displayed a variety of expression patterns at different development stages. The expression levels of HaxyOBP3 and HaxyOBP15 were higher in the adult stage than in the other developmental stages, and HaxyOBP15 was significantly transcriptionally enriched in adult stage. Ligand-binding analysis demonstrated that HaxyOBP3 and HaxyOBP12 only combined with two compounds, β-ionone and p-anisaldehyde. HaxyOBP5 protein displayed binding affinities with methyl salicylate, β-ionone, and p-anisaldehyde (Ki = 18.15, 11.71, and 13.45 μM). HaxyOBP15 protein had a broad binding profile with (E)-β-farnesene, β-ionone, α-ionone, geranyl acetate, nonyl aldehyde, dihydro-β-ionone, and linalyl acetate (Ki = 4.33–31.01 μM), and hydrophobic interactions played a key role in the binding of HaxyOBP15 to these substances according to molecular docking. Taken together, HaxyOBP15 exhibited a broader ligand-binding spectrum and a higher expression in adult stage than HaxyOBP3, 5, and 12, indicating HaxyOBP15 may play a greater role in binding volatiles than other three HaxyOBPs. The results will increase our understanding of the molecular mechanism of H. axyridis olfaction and may also result in new management strategies (attractants/repellents) that increase the biological control efficacy of H. axyridis.

Anastatus japonicus Ashmead is an egg parasitoid wasp important for the biological control of fruit crop pests. The olfaction of parasitoids is crucial to searching for host pests in fruit crops. In this study, we sequenced and analyzed the antennal and abdominal transcriptomes of A. japonicus to better understand the olfactory mechanisms in this species. A total of 201 putative olfactory receptor genes were identified, including 184 odorant receptors (ORs) and 17 ionotropic receptors (IRs). Then, we assayed the tissue-specific and sex-biased expression profiles of those genes based on the transcriptional levels. In total, 165 ORs and 15 IRs had upregulated expression in the antennae. The expression levels of 133 ORs, including odorant receptor co-receptor (AjapORco), and 10 IRs, including AjapIR8a, were significantly different between the female and male antennae. Our results provide valuable information for further studies on the molecular mechanisms of the olfactory system in A. japonicus.

Abstract: (E)-β-Caryophyllene is a sesquiterpene compound widely distributed in plants and functions in plant defence. However, little is known about the sequence and function of (E)-β-caryophyllene synthase in lima bean (Phaseolus lunatus). Here, we report a new full-length cDNA (PlCAHS) encoding (E)-β-caryophyllene synthase, a possible key enzyme of plant defence. The cDNA of PlCAHS contains an open reading frame of 1 761 bp, encoding a protein of 586 amino acids with a predicted mass of 67.95 kDa. The deduced amino acid sequence shows 52% identity with sesquiterpene synthase MtCAHS of Medicago truncatula. Based on phylogenetic analysis, PlCAHS is classified as the terpene synthases (TPS)-a subfamily. The recombinant enzyme, expressed in Escherichia coli, catalysed the formation of a major product (E)-β-caryophyllene (82%) and a minor product α-humulene (18%) from farnesyl diphosphate. Real-time quantitative PCR (qRT-PCR) analysis found that the PlCAHS transcript was significantly up-regulated in leaves after treatment with spider mites and alamethicin (ALA), suggesting its ecological function in plant defence.

Abstract The sycamore lace bug, Corythucha ciliata, is a pest of sycamore trees. In China, it is found in the most northern border where it has been known to become dormant during harsh winters. But the molecular and metabolic basis for dormancy in this insect is still unknown. In this study, we analyzed the transcript and metabolite profiles of this bug to identify key genes and metabolites that are significantly regulated during dormancy in adult females and males. In total, 149 differentially expressed genes (DEGs) were significantly up-regulated and 337 DEGs were significantly down-regulated in dormant adults (both females and males). We found major differences in heat shock protein (HSPs), immunity-responsive genes, NAD-dependent deacetylase sirtuin-1 (SIRT1) and genes involved in the spliceosome pathway that is known to regulate stress. Among the 62 metabolites identified by GC-MS, 12 metabolites including glycerol, trehalose, and alanine were significantly increased during C. ciliata dormancy. By integrating the transcriptome and metabolite datasets, we found that the metabolites in glycolysis/gluconeogenesis and citrate cycle (TCA) were significantly reduced. This study is the first to report both transcript and metabolite profiles of the overwintering responses of C. ciliata to cold stress at the molecular level.

Insect cuticle is an apical extracellular matrix produced by the epidermis, tracheal, hind‐ and foregut epithelia during embryogenesis and renewed during molting and metamorphosis. However, the underlying regulatory mechanism for embryonic cuticle formation remains largely unclear. Here, we investigate the function of the transcription factor POUM2 in the embryonic cuticular formation in Bombyx mori, a model lepidopteran insect. Clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR‐associated protein‐9‐mediated knockout of POUM2 resulted in the defect of cuticular deposition, pigmentation, and sclerotization in the embryos. Differentially expressed transcripts analysis of 7‐d‐old embryos identified 174 up‐ or downregulated cuticular protein transcripts, 8 upregulated chitin degradation transcripts, 2 downregulated chitin synthesis transcripts and 48 up‐ or downregulated transcription factor transcripts in the POUM2−/− embryos. The expression levels of the key factors of the tyrosine metabolic pathway, such as tyrosine hydroxylase (Th), Dopa decarboxylase (DDC), and arylalkylamine N‐acetyltransferase (aaNAT), were significantly decreased in the POUM2−/− embryos. POUM2 isoform POUM2‐L specifically bound the POU cis‐regulatory element (CRE) in the Th promoter and increased the transcription of Th, whereas POUM2‐S could not bind the POU CRE, although it also increased the transcription of Th. Heterogeneous nuclear ribonucleoprotein Squid‐1 directly bound the POUM2 pre‐mRNA (messenger RNA) and inhibited the alternative splicing of POUM2‐L to POUM2‐S mRNA. These results suggest that POUM2 participates in the cuticular formation by regulating the chitin and cuticular protein synthesis and metabolism, and the cuticular pigmentation and sclerotization by regulating tyrosine metabolism during embryogenesis. This study provides new insights into novel function of POUM2 in embryogenesis. [ABSTRACT FROM AUTHOR]

Long wavelength InAs/AlSb quantum cascade lasers (QCLs) emitting at 13 μm, based on a diagonal transition scheme design through band structure engineering, have been grown and fabricated. This band structure engineering focuses on enhancing transition efficiency and suppressing carrier leakage. Our 3-mm-long, 25-μm-wide InAs/AlSb QCL has achieved a slope efficiency of 210 mW/A and a maximum peak power of 515 mW, despite encountering a substantial waveguide loss of 27 cm−1 and a relatively high threshold of 4.8 kA/cm2, due to the elevated residual doping level. Our InAs/AlSb QCL devices have demonstrated record-breaking performance in terms of slope efficiency, maximum peak power, and injection efficiency. Cavity length analysis suggests that reducing the residual doping by half could pave the way for achieving continuous wave output power in the realm of hundreds of milliwatts at room temperature for our designed 13 μm QCLs.

BackgroundThe relationship between white matter hyperintensities (WMH) and the core features of Alzheimer’s disease (AD) remains controversial. Further, due to the prevalence of co-pathologies, the precise role of WMH in cognition and neurodegeneration also remains uncertain.MethodsHerein, we analyzed 1803 participants with available WMH volume data, extracted from the ADNI database, including 756 cognitively normal controls, 783 patients with mild cognitive impairment (MCI), and 264 patients with dementia. Participants were grouped according to cerebrospinal fluid (CSF) pathology (A/T profile) severity. Linear regression analysis was applied to evaluate the factors associated with WMH volume. Modeled by linear mixed-effects, the increase rates (Δ) of the WMH volume, cognition, and typical neurodegenerative markers were assessed. The predictive effectiveness of WMH volume was subsequently tested using Cox regression analysis, and the relationship between WMH/ΔWMH and other indicators such as cognition was explored through linear regression analyses. Furthermore, we explored the interrelationship among amyloid-β deposition, cognition, and WMH using mediation analysis.ResultsHigher WMH volume was associated with older age, lower CSF amyloid-β levels, hypertension, and smoking history (all p ≤ 0.001), as well as cognitive status (MCI, p

Spodoptera litura is a destructive agricultural pest in tropical and subtropical areas. Understanding the molecular mechanisms of S. litura adaptation to its preferred host plants may help identify target genes useful for pest control. We used high‐throughput sequencing to characterize the expression patterns of messenger RNAs (mRNAs) and microRNAs (miRNAs) in the midgut of S. litura fed on Brassica juncea for 6 h and 48 h. A total of 108 known and 134 novel miRNAs were identified, 29 miRNAs and 237 mRNAs were differentially expressed at 6 h of B. juncea feeding, 26 miRNAs and 433 mRNAs were differentially expressed at 48 h. For the mRNAs, the up‐regulated genes were mostly enriched in detoxification enzymes (cytochrome P450, esterase, glutathione S‐transferase, uridine diphosphate‐glucuronosyl transferase), while the down‐regulated genes were mostly enriched in proteinases and immune‐related genes. Furthermore, most detoxification enzymes begin to up‐regulate at 6 h, while most digestion and immune‐related genes begin to up‐ or down‐regulate at 48 h. Eighteen and 37 differently expressed transcription factors were identified at 6 h and 48 h, which may regulate the functional genes. We acquired 136 and 41 miRNA versus mRNA pairs at 6 h and 48 h, respectively. Some down‐regulated and up‐regulated miRNAs were predicted to target detoxification enzymes and proteinases, respectively. Real‐time quantitative polymerase chain reaction of nine randomly selected miRNAs and 28 genes confirmed the results of RNA‐seq. This analyses of miRNA and mRNA transcriptomes provides useful information about the molecular mechanisms of S. litura response to B. juncea. [ABSTRACT FROM AUTHOR]

Krüppel homolog 1 (Kr‐h1), a zinc finger transcription factor, is involved in the metamorphosis and adult reproduction of insects. However, the role of Kr‐h1 in reproduction of holometabolic insects remains to be elucidated. The regulation network of Kr‐h1‐associated genes in the reproduction in Bombyx mori was investigated in this study. The higher expression level of BmKr‐h1 in the ovaries was detected during the late pupal stage and adults. RNA interference (RNAi)‐mediated depletion of BmKr‐h1 in the female at day 6 of pupae resulted in abnormal oocytes at 48 h post‐double‐stranded RNA treatment, which showed less yolk protein deposition and partially transparent chorion. RNA‐seq and subsequent differentially expressed transcripts analysis showed that knockdown of BmKr‐h1 caused a decrease in the expression of 2882 genes and an increase in the expression of 2565 genes in the oocytes at day 8 of pupae. Totally, 27 genes coding for transcription factors were down‐regulated, while six genes coding for other transcription factors were up‐regulated. BmKr‐h1 bound to the Kr‐h1 binding site of the transcription factors AP‐1 (activating protein‐1) and FOXG1 to increase their messenger RNA transcripts in the BmN cells, respectively. Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses of that positively co‐expressed with AP‐1 and FOXG1 transcripts showed mainly enrichment in the metabolic‐related pathways, the nutrient absorption and the yolk protein absorption processes. These data suggested that BmKr‐h1 might directly regulate the metabolic‐related pathways, the nutrient absorption and the yolk protein absorption processes or probably through AP‐1 and /or FOXG1 to regulate oocyte development. [ABSTRACT FROM AUTHOR]

Metamorphosis is one of the most important physiological processes in insects. It is regulated by a serial of ecdysone cascade genes. Recently, lots of microRNAs (miRNAs) were investigated in insects; however, their function in metamorphosis is largely unknown. In the present study, the dynamics of a small RNA population was investigated by RNA sequencing from the midgut of a lepidopteran pest Spodoptera litura during larval–pupal metamorphosis. A total of 101 miRNAs were identified, and 75 miRNAs were differentially expressed during the metamorphic process. The relationship between these differentially expressed miRNAs and 12 ecdysone cascade genes was analyzed by four classical software programs, and a multiple‐to‐multiple regulatory network was found to exist between these miRNAs and their targets. Among them, miR‐14‐3p and its two targets (EcR and E75) were chosen for further validation. MiR‐14‐3p had higher expression level in the 6th instar larvae as compared with either the prepupae or pupae, which was opposite to that of both EcR and E75, two ecdysone cascade genes. Luciferase reporter assay confirmed that both EcR and E75 were regulated by miR‐14‐3p. Interestingly, the 3′ untranslated regions are nearly identical to each other among different transcript variants of the ecdysone cascade genes, including EcR, USP, E75, E74, E78, E93, Hr3, Hr4, Hr39, Krh1 and Ftzf1. Thus, different transcript variants of one ecdysone cascade gene could be regulated by the same miRNA. The above data suggest that the ecdysone signaling pathway is under the tight control of miRNA. These findings expand our understanding of the mechanism of insect metamorphosis and may also provide a novel possibility for the control of pest insects in the future. [ABSTRACT FROM AUTHOR]

The fall armyworm Spodoptera frugiperda recently invaded China, ravaging crops in many provinces. Deciphering the possible genetic basics for its successful invasion is critical for innovative and specific control for this gluttonous pest. Here we generated comparative genomic analyses between S. frugiperda and its native relative, S. litura, which differs in host preference, locomotivity and production behavior. We demonstrated that S. frugiperda genes are enriched in taste sensory perception and nervous system, obviously different from those of S. litura. Potential host adaptation genes showed generally an elevated ratio of non‐synonymous substitution rate to synonymous substitution rate, suggesting a faster evolution during the divergence of the two species. Focusing on these sets of genes, we identified 23 genes being under positive selection in S. frugiperda. Among them are two notable genes involved in sensory perception, gustatory receptor (GR) and an acetaldehyde oxidase, which are important for host detection in invasion and expansion processes. Another two genes are mitochondrial adenosine triphosphate synthase β subunit and ferritin heavy chain, which may be associated with the enhanced locomotivity and resistance, which fascinated long‐distance migration needed for invasion and rapid expansion. Another interesting gene is chorion protein, in which positive selection sites in S. frugiperda were found and a replacement in one site is predicted to affect the protein function, which might be associated with competent reproductivity in S. frugiperda to ensure genetic resources for expansion. [ABSTRACT FROM AUTHOR]

Fusion of the testis occurs in most Lepidoptera insects, including Spodoptera litura, an important polyphagous pest. Testicular fusion in S. litura is advantageous for male reproduction, and the molecular mechanism of fusion remains unknown. Doublesex influences the formation of genitalia, the behavior of courtship, and sexually dimorphic traits in fruit‐fly and silkworm, and is essential for sexual differentiation. However, its purpose in the testis of S. litura remains unknown. The doublesex gene of S. litura (Sldsx) has male‐specific SldsxM and female‐specific SldsxF isoforms, and exhibits a higher expression level in the male testis. At the testicular fusion stage (L6D6), Sldsx attained the highest expression compared to the pre‐fusion and post‐fusion periods. Moreover, Sldsx had a higher expression in the peritoneal sheaths of testis than that of germ cells in the follicle. CRISPR/Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats/Cas9) was applied to S. litura to determine the role of Sldsx. A mixture of single guide RNA messenger RNA and Cas9 protein (300 ng/μL each) was injected into eggs within 2 h following oviposition. CRISPR/Cas9 successfully induced genomic mutagenesis of Sldsx at G0 generation. The mutant males had smaller testis surrounded by less tracheae. Moreover, the mutant males had abnormal external genitalia and could not finish mating with wild‐type females. Additionally, testes were fused for almost all mutant males. The results showed that Sldsx was not related to testicular fusion, and is required for both testis development and the formation and function of external genitalia in S. litura. The main roles of doublesex on the male are similar to other insects. [ABSTRACT FROM AUTHOR]

Silkworm mutants are valuable resources for both transgenic breeding and gene discovery. PiggyBac‐based random insertional mutagenesis has been widely used in gene functional studies. In order to discover genes involved in silk synthesis, a piggyBac‐based random insertional library was constructed using Bombyx mori, and the mutants with abnormal cocoon were particularly screened. By this means, a "thin cocoon" mutant was identified. This mutant revealed thinner cocoon shell and shorter posterior silk gland (PSG) compared with the wild type. The messenger RNA (mRNA) levels of all the three fibroin genes, including Fib‐H, Fib‐L and P25, were significantly down‐regulated in the PSG of mutants. Four piggyBac insertion sites were identified in Aquaporin (AQP), Longitudinals lacking protein‐like (Lola), Glutamyl aminopeptidase‐like (GluAP) and Loc101744460. The mRNA levels of all the four genes were significantly altered in the silk gland of mutants. In particular, the mRNA amount of AQP, a gene responsible for the regulation of osmotic pressure, decreased dramatically immediately prior to the spinning stage in the anterior silk gland of mutants. The identification of the genes disrupted in the "thin cocoon" mutant in this study provided useful information for understanding silk production and transgenic breeding of silkworms in the future. [ABSTRACT FROM AUTHOR]

The insect exoskeleton is mainly composed of chitin filaments linked by cuticle proteins. When insects molt, the cuticle of the exoskeleton is renewed by degrading the old chitin and cuticle proteins and synthesizing new ones. In this study, chitin-binding activity of the wing disc cuticle protein BmWCP4 in Bombyx mori was studied. Sequence analysis showed that the protein had a conservative hydrophilic 'R&R' chitin-binding domain (CBD). Western blotting showed that BmWCP4 was predominately expressed in the wing disc-containing epidermis during the late wandering and early pupal stages. The immunohistochemistry result showed that the BmWCP4 was mainly present in the wing disc tissues containing wing bud and trachea blast during day 2 of wandering stage. Recombinant full-length BmWCP4 protein, 'R&R' CBD peptide (CBD), non-CBD peptide (BmWCP4-CBD−), four single site-directed mutated peptides (M1, M2, M3 and M4) and four-sites-mutated peptide (MF) were generated and purified, respectively, for in vitro chitin-binding assay. The results indicated that both the full-length protein and the 'R&R' CBD peptide could bind with chitin, whereas the BmWCP4-CBD− could not bind with chitin. The single residue mutants M1, M2, M3 and M4 reduced but did not completely abolish the chitin-binding activity, while four-sites-mutated protein MF completely lost the chitin-binding activity. These data indicate that BmWCP4 protein plays a critical role by binding to the chitin filaments in the wing during larva-to-pupa transformation. The conserved aromatic amino acids are critical in the interaction between chitin and the cuticle protein. [ABSTRACT FROM AUTHOR]

Juvenile hormone (JH) is one of the key insect hormones that regulate metamorphosis. Juvenile hormone diol kinase (JHDK) is an enzyme involved in JH metabolism and catalyzes JH diol to form a polar end product, JH diol phosphate that has no JH activity. In this study, a JHDK complementary DNA (cDNA) was cloned from Spodoptera litura and the structure and expression of the gene was characterized. The cDNA was 714 base pairs in length and encoded a protein of 183 amino acids with a molecular mass of 21 kDa and an isoelectric point of 4.55. Based on the structure, three putative calcium binding motifs and guanosine triphosphate-binding motifs were predicted in the protein. Modeling of the 3-D structure showed that the protein consisted of eight α-helixes linked with loops, with no β-sheets. The gene was expressed in the epidermis, fat body and midgut of fifth and sixth instar larvae. The expression level in the epidermis was lower than in the fat body and midgut. The gene was expressed at higher levels at the early stages than in the later stages of fifth and sixth instar midgut and fat body. The results suggest that this gene may be involved in the regulation of the JH titer in larvae of S. litura. [ABSTRACT FROM AUTHOR]

Chlorpyrifos (CPF) is a broad-spectrum organophosphate insecticide. Glutathione S-transferases (GSTs) in insects are a family of detoxification enzymes and they play critical roles in CPF detoxification. Spodoptera litura is one of the most destructive agricultural pests in tropical and subtropical areas in the world. In this study, 37 Slgsts from 46 unique transcripts of gsts in S. litura transcriptome data, including eight previously reported GSTs, were identified and their expression patterns in susceptible and 12-generation-CPF-treated strains were analyzed to understand the roles of these Slgsts in sublethal doses of CPF tolerance. The results indicate that the members of the S. litura GST superfamily could be distinguished into three major groups: one group, including six cytosolic Slgsts ( SlGSTe1, SlGSTe3, SlGSTe10, SlGSTe15, SlGSTo2 and SlGSTs5) and two microsomal Slgsts ( SlMGST1-2 and SlMGST1-3), was directly responsible for CPF induction in both 12-generation-treated and susceptible strains; the second group, including three cytosolic Slgsts ( SlGSTe13, SlGSTt1 and SlGSTz1) and one microsomal Slgst ( SlMGST1-1), was induced only in the 12-generation-treated strain; the third group, including eight cytosolic Slgsts (two epsilon, three delta, one omega, one zeta and one unclassified Slgst), was expressed 1.52-5.15-fold higher in the 12-generation-treated strain than in the susceptible strain. [ABSTRACT FROM AUTHOR]

Abstract In this paper, an anomalous spectral data of distributed Bragg reflector (DBR) quantum cascade lasers (QCLs) emitting around 7.6 μm is presented. The two-section DBR lasers, consisting of a gain section and an unpumped Bragg reflector, display an output power above 0.6 W in continuous wave (CW) mode at room temperature. The anomalous spectral data is defined as a longitudinal mode which moves toward shorter wavelengths with increasing temperature or injection current, which is unexpected. Although the longer wavelength modes are expected to start lasing when raising device temperature or injection current, occasional mode hops to a shorter wavelength are seen. These anomalous mode transitions are explained by means of modal analysis. The thermal-induced change of the refractive index implied by an increase in the temperature or injection current yields nearly periodic transitions between cavity modes.

Abstract High-power, low-threshold stable single-mode operation buried distributed feedback quantum cascade laser by incorporating sampled grating emitting at λ ~ 4.87 μm is demonstrated. The high continuous wave (CW) output power of 948 mW and 649 mW for a 6-mm and 4-mm cavity length is obtained at 20 °C, respectively, which benefits from the optimized optical field distribution of sampled grating. The single-mode yields of the devices are obviously enhanced by controlling cleaved positions of the two end facets precisely. As a result, stable single-mode emission and mode tuning linearly without any mode hopping of devices are obtained under the different heat sink temperatures or high injection currents.

Thyroid cancer is a common malignant tumor of the endocrine glands. Although surgery is the optimal treatment utilized, the disease is characterized by recurrence and metastasis. The aim of the present study was to determine the effect of iodine-131 (131I) 'clear residual thyroid tissue' following surgery on the treatment of differentiated thyroid cancer (DTC) and its effect on the function of the parathyroid gland. A total of 160 patients diagnosed with DTC, who were consecutively admitted to our Hospital between June 2012 and June 2014 and underwent total thyroidectomy or subtotal resection, were included in the present study. After three months, the patients were administered 131I 'clear residual thyroid tissue' treatment and underwent a whole body scan after 1 week to determine whether 'clear residual thyroid tissue' treatment was successful or not. The treatment was repeated within 3 months if not successful. Of the 160 patients, 24 patients had cancer metastasis (15.0%). The average dose of 131I used for the first time was 6.4+1.2 GBq and the treatment was successful in 66 cases (41.3%). The average treatment time was 2.8±0.6 therapy sessions. The results showed that, prior to and following the first treatment and at the end of the follow up, levels of the parathyroid hormone, serum calcium and phosphorus were compared, and no statistically significant difference (P>0.05) was observed. There were 5 patients with persistent hypothyroidism and 8 patients with transient hypothyroidism. The levels of thyroglobulin were significantly decreased, and the difference was statistically significant (P<0.05). A total of 48 patients (30%) with hypothyroidism were identified. In conclusion, the results have shown that DTC resection and 131I 'clear residual thyroid tissue' treatment did not significantly impair the parathyroid function, thereby improving the treatment effect. [ABSTRACT FROM AUTHOR]

Insect glutathione S-transferases (GSTs) play important roles in detoxifying toxic compounds and eliminating oxidative stress caused by these compounds. In this study, detoxification activity of the epsilon GST SlGSTE1 in Spodoptera litura was analyzed for several insecticides and heavy metals. SlGSTE1 was significantly up-regulated by chlorpyrifos and xanthotoxin in the midgut of S. litura. The recombinant SlGSTE1 had Vmax (reaction rate of the enzyme saturated with the substrate) and Km (michaelis constant and equals to the substrate concentration at half of the maximum reaction rate of the enzyme) values of 27.95 ± 0.88 μmol/min/mg and 0.87 ± 0.028 mmol/L for glutathione, respectively, and Vmax and Km values of 22.96 ± 0.78 μmol/min/mg and 0.83 ± 0.106 mmol/L for 1-chloro-2,4-dinitrobenzene, respectively. In vitro enzyme indirect activity assay showed that the recombinant SlGSTE1 possessed high binding activities to the insecticides chlorpyrifos, deltamethrin, malathion, phoxim and dichloro-diphenyl-trichloroethane (DDT). SlGSTE1 showed higher binding activity to toxic heavy metals cadmium, chromium and lead than copper and zinc that are required for insect normal growth. Western blot analysis showed that SlGSTE1 was induced in the gut of larvae fed with chlorpyrifos or cadmium. SlGSTE1 also showed high peroxidase activity. All the results together indicate that SlGSTE1 may play an important role in the gut of S. litura to protect the insect from the toxic effects of these compounds and heavy metals. [ABSTRACT FROM AUTHOR]

Ecdysone receptor (EcR) and ultraspiracle (USP) form heterodimers to mediate ecdysteroid signaling during molting and metamorphosis. Various EcR/USP heterodimers have been reported. However, it is unclear what kind of EcR/USP combination is adopted by lepidopteran insects during the larval-pupal metamorphosis and whether the EcR/USP heterodimer varies among different tissues. To address these questions, two isoforms of each EcR and USP were cloned from the common cutworm, their messenger RNA expression patterns were examined by real-time quantitative polymerase chain reaction in different tissues during the larval-pupal metamorphosis and in the midgut in response to hormonal induction. Furthermore, their subcellular localization and protein-protein interaction were explored by transient expression and far-western blotting, respectively. All the four genes were significantly up-regulated in prepuae and/or pupae. The expression profiles of EcRB1 and USP1 were nearly identical to each other in the epidermis, fat body and midgut, and a similar situation also applied to EcRA and USP2. The three genes responded to 20-hydroxyecdysone (20E) induction except for USP2, and USP1 could be up-regulated by both 20E and juvenile hormone. The four proteins mainly localized in the nucleus and the nuclear localization was promoted by 20E. The protein-protein interaction between each EcR and USP was found in vitro. These results suggest that two types of EcR/USP heterodimer (EcRA/USP2 and EcRB1/USP1) may exist simultaneously in the common cutworm, and the latter should play more important roles during the larval-pupal metamorphosis. In addition, the types of EcR/USP heterodimer do not vary in the tissues which undergo histolysis and regeneration during metamorphosis. [ABSTRACT FROM AUTHOR]

Insect midgut secretes a semi-permeable peritrophic membrane (PM), which plays important roles in protecting the midgut and helping with food digestion. The lepidopteran larvae produce type 1 PM, which is degraded when insects develop into the metamorphic stages. However, the underlying mechanism is unclear. In the present study, two peritrophin-like proteins (peritrophin-57 and 37) were identified from the midgut expression sequence tag library and transcriptome of the common cutworm, Spodoptera litura. The temporal and spatial expression patterns and responses to the induction of 20-hydroxyecdysone (20E) and starvation were examined by real-time quantitative polymerase chain reaction according to their common sequence region. The chitin-binding activity was also studied using a competitor, calcofluor. The open reading frames are 1 554 and 1 020 bp, respectively. They shared four highly conserved peritrophin-A domains and were expressed only in the midgut rather than in the other tissues, including fat body, epidermis, Malpighian tube and hemolymph. Their transcriptional expression could only be detected at the larval stages rather than in eggs, prepupae, pupae and adults. The purified protein of peritrophin-37 bound to chitin in a dose-dependent manner. These results indicate that the two proteins are peritrophins, the structural components of PM. In addition, the messenger RNA levels of the two peritrophins were significantly down-regulated by 20E injection, whereas feeding/starvation had no effect on the expression. These findings suggest that the increase of 20E titer may be an important factor which controls the degradation of PM during metamorphosis. [ABSTRACT FROM AUTHOR]

Abstract Power scaling in broad area quantum cascade laser (QCL) usually leads to the deterioration of the beam quality with an emission of multiple lobes far-field pattern. In this letter, we demonstrate a tapered QCL array integrated with Talbot cavity at one side of the array. Fundamental supermode operation is achieved in the arrays with taper straight-end connected to the Talbot cavity. Lateral far-field of the fundamental supermode shows a near diffraction limited beam divergence of 2.7°. The output power of a five-element array is about three times as high as a single-ridge laser with an emission wavelength of around 4.8 μm. However, arrays with the taper-end connected to the Talbot cavity always show a high-order supermode operation whatever Talbot cavity length is.

Abstract In this work, quantum cascade lasers (QCLs) based on strain compensation combined with two-phonon resonance design are presented. Distributed feedback (DFB) laser emitting at ~ 4.76 μm was fabricated through a standard buried first-order grating and buried heterostructure (BH) processing. Stable single-mode emission is achieved under all injection currents and temperature conditions without any mode hop by the optimized antireflection (AR) coating on the front facet. The AR coating consists of a double layer dielectric of Al2O3 and Ge. For a 2-mm laser cavity, the maximum output power of the AR-coated DFB-QCL was more than 170 mW at 20 °C with a high wall-plug efficiency (WPE) of 4.7% in a continuous-wave (CW) mode.

BACKGROUND: Termites are worldwide pests causing considerable damage to agriculture, forestry and buildings. While various approaches have been tried to eliminate termite populations, the relevant toxicants are associated with certain risks to the environment and human health. RESULTS: In this study, to combine the merits of effective chemical control by bifenthrin and a drug photoimmobilisation technique, silk fibroin was used as a carrier to embed bifenthrin, which was then photoactively immobilised by ultraviolet treatment on the surface of wood (cellulose). The immobilised bifenthrin embedded in the photoactive silk fibroin was characterised by Fourier transform infrared spectroscopy (FTIR), ultraviolet absorption spectroscopy (UV), fluorescence measurement and CHN analysis. The surface structures and biological activity were examined by scanning electron microscopy (SEM), atomic force microscopy (AFM), electron spectroscopy for chemical analysis (ESCA) and bioassays respectively. CONCLUSIONS: The results indicate that the embedded and immobilised bifenthrin has been very well protected from free release and has a long-term stability allowing slow release with a high efficiency against termites at a low dose of 1.25 µg cm [ABSTRACT FROM AUTHOR]

A trypsin-like molting-related serine protease cDNA ( CfMRSP) was cloned from the spruce budworm, Choristoneura fumiferana. The full-length CfMRSP complementary DNA (cDNA) encoded a 43 kDa protein that contained a trypsin-like serine protease catalytic domain, but no clip domain. The C-terminal extension contained five cystein residues, which may allow the protein to form a homodimer through interchain disulfide bonds and regulate the activity of CfMRSP. Phylogenetic tree analysis showed that CfMRSP clusters with lepidopteran homologues such as serine protease 1 of Lonomia obliqua, hemolymph proteinase 20 (HP20), pattern recognition serine proteinase precursor (ProHP14) and a trypsin-like protein of Manduca sexta. Northern blot analysis of developmental expression of CfMRSP indicated that its transcripts were found primarily in the epidermis and were produced during all of the tested stadia, from 4th instar larvae to pupae, but increased levels of CfMRSP transcripts were always found after each molt. A high level of the protein was found in the epidermis by immunohistochemistry analysis. Altogether these data suggest that CfMRSP plays a role in the epidermis during molting and metamorphosis. [ABSTRACT FROM AUTHOR]

Carex rigescens (Franch.) V. Krecz is a wild turfgrass perennial species in the Carex genus that is widely distributed in salinised areas of northern China. To investigate genome-wide salt-response gene networks in C. rigescens, transcriptome analysis using high-throughput RNA sequencing on C. rigescens exposed to a 0.4% salt treatment (Cr_Salt) was compared to a non-salt control (Cr_Ctrl). In total, 57742546 and 47063488 clean reads were obtained from the Cr_Ctrl and Cr_Salt treatments, respectively. Additionally, 21954 unigenes were found and annotated using multiple databases. Among these unigenes, 34 were found to respond to salt stress at a statistically significant level with 6 genes up-regulated and 28 down-regulated. Specifically, genes encoding an EF-hand domain, ZFP and AP2 were responsive to salt stress, highlighting their roles in future research regarding salt tolerance in C. rigescens and other plants. According to our quantitative RT-PCR results, the expression pattern of all detected differentially expressed genes were consistent with the RNA-seq results. Furthermore, we identified 11643 simple sequence repeats (SSRs) from the unigenes. A total of 144 amplified successfully in the C. rigescens cultivar Lüping 1, and 69 of them reflected polymorphisms between the two genotypes tested. This is the first genome-wide transcriptome study of C. rigescens in both salt-responsive gene investigation and SSR marker exploration. Our results provide further insights into genome annotation, novel gene discovery, molecular breeding and comparative genomics in C. rigescens and related grass species.

Abstract In the present work, an ultra-low power consumption substrate-emitting distributed feedback (DFB) quantum cascade laser (QCL) was developed. The continuous-wave (CW) threshold power dissipation is reduced to 0.43 W at 25 °C by shortening the cavity length to 0.5 mm and depositing high-reflectivity (HR) coating on both facets. As far as we know, this is the recorded threshold power dissipation of QCLs in the same conditions. Single-mode emission was achieved by employing a buried second-order grating. Mode-hop free emission can be observed within a wide temperature range from 15 to 105 °C in CW mode. The divergence angles are 22.5o and 1.94o in the ridge-width direction and cavity-length direction, respectively. The maximum optical power in CW operation was 2.4 mW at 25 °C, which is sufficient to spectroscopy applications.

Abstract Very low power-consumption distributed feedback (DFB) quantum cascade lasers (QCLs) at the wavelength around 4.9 μm were fabricated by conventional process without lateral regrowth of InP:Fe or using sidewall grating. Benefitted from the optimized materials and low waveguide loss, very low threshold current density of 0.5 kA/cm2 was obtained for a device with cavity length of 2 mm. Combined with the partial-high-reflection coating, the 1-mm-long DFB QCL achieved low power-consumption continuous wave (CW) operation up to 105 °C. The CW threshold power-consumptions were 0.72 and 0.78 W at 15 and 25 °C, respectively. The maximum CW output power was over 110 mW at 15 °C and still more than 35 mW at 105 °C. At 15 °C, wall-plug efficiency of 5.5% and slope efficiency of 1.8 W/A were deduced, which were very high for low power-consumption DFB QCLs.

Objective(s): The present study was aimed to investigate the influence of thoracic epidural blockade on hypoxia-induced pulmonary hypertension in rats. Materials and Methods: Forty eight Wistar rats were randomly divided into 4 equal groups, named normoxia hypoxia hypoxia/ ropivacaine and hypoxia/saline. Animals were placed in a hypoxia chamber and instrumented with epidural catheters at the thoracic level. Rats were injected with saline or ropivacaine. Haemodynamic measurements included pulmonary artery pressure and right ventricular hypertrophy. Degree of pulmonary vascular remodeling was determined by Hematoxylin and Eosin (HE) staining. Serum cyclic GMP (cGMP) and TNF-α were measured using radioimmuno assay. Real-time PCR and western boltting were employed to examine the expression of cAMP responding-element binding protein (CREB). Results: We found that the thoracic epidural blockade significantly decreased chronic hypoxia-induced pulmonary hypertension and vascular remodeling in rats. Ropivacaine-treated rats exhibited significantly lower mean pulmonary artery pressure (mPAP), ratio of right ventricular weight to left ventricular plus septal weight (RV/(LV+S)) and wall thickness of pulmonary artery compared with those of control rats. Hypoxia-induced increase in levels of serum cGMP and TNF-α was reversed by thoracic epidural blockade. Moreover, hypoxia increased expression of CREB at mRNA and protein levels which could be suppressed by thoracic epidural blockade. Conclusion:Thoracic epidural blockade reduced mPAP and serum level of TNF-α and increased cGMP. The treatment reversed upregulated expression of CREB at mRNA and protein production.

A phase-locked quantum cascade laser (QCL) array consisting of one hundred elements that were integrated in parallel was achieved at λ ∼ 4.6 μm. The proposed Fraunhofer’s multiple slits diffraction model predicted and explained the far-field pattern of the phase-locked laser array. A single-lobed far-field pattern, attributed to the emission of an in-phase-like supermode, is obtained near the threshold (Ith). Even at 1.5 Ith, greater than 73.3% of the laser output power is concentrated in a low-divergence beam with an optical power of up to 40 W.

The migratory locust displays a reversible, density-dependent transition between the two phases of gregaria and solitaria. This phenomenon is a typical kind of behavior plasticity. Here, we report that COP9 signalosome complex subunit 7A (CSN7A) is involved in the regulation of locust phase transition. Firstly, 90 proteins were identified to express differentially between the two phases by quantitative proteomic analysis. Gregaria revealed higher levels in proteins related to structure formation, melanism and energy metabolism, whereas solitaria had more abundant proteins related to digestion, absorption and chemical sensing. Subsequently, ten proteins including CSN7A were found to reveal differential mRNA expression profiles between the two phases. The CSN7A had higher mRNA level in the gregaria as compared with the solitaria, and the mRNA amount in the gregaria decreased remarkably during the 32 h-isolation. However, the mRNA level in the solitaria kept constant during the crowding rearing. Finally and importantly, RNA interference of CSN7A in gregaria resulted in obvious phase transition towards solitaria within 24 h. It suggests that CSN7A plays an essential role in the transition of gregaria towards solitaria in the migratory locust. To our knowledge, it's the first time to report the role of CSN in behavior plasticity of animals. [ABSTRACT FROM AUTHOR]

Juvenile hormone (JH) is one of key insect hormones that regulate metamorphosis. Juvenile hormone diol kinase (JHDK) is an enzyme involved in JH metabolism and catalyzes JH diol to form a polar end product, JH diol phosphate that has no JH activity. In this study, a JHDK cDNA was cloned from Spodoptera litura and the structure and expression of the gene was characterized. The cDNA was 714 base pairs in length and encoded a protein of 183 amino acids with a molecular mass of 21 kDa and a pI of 4.55. Based on the structure three putative calcium binding motifs and GTP‐binding motifs were predicted in the protein. Modeling of the 3‐D structure showed that the protein consisted of eight α‐helixes linked with loops, with no β‐sheets. The gene was expressed in the epidermis, fat body and midgut of 5th and 6th instar larvae. The expression level in the epidermis was lower than in the fat body and midgut. The gene was expressed at higher levels at the early stages than in the later stages of 5th and 6th instar midgut and fat body. The results suggest that this gene may be involved in the regulation of the JH titer in larvae of S. litura.This article is protected by copyright. All rights reserved [ABSTRACT FROM AUTHOR]

Cell division and differentiation after egg fertilization are critical steps in the development of embryos from single cells to multicellular individuals and are regulated by DNA methylation via its effects on gene expression. However, the mechanisms by which DNA methylation regulates these processes in insects remain unclear. Here, we studied the impacts of DNA methylation on early embryonic development in Bombyx mori . Genome methylation and transcriptome analysis of early embryos showed that DNA methylation events mainly occurred in the 5' region of protein metabolism-related genes. The transcription factor gene zinc finger protein 615 ( ZnF615 ) was methylated by DNA methyltransferase 1 (Dnmt1) to be up-regulated and bind to protein metabolism-related genes. Dnmt1 RNA interference (RNAi) revealed that DNA methylation mainly regulated the expression of nonmethylated nutrient metabolism-related genes through ZnF615 . The same sites in the ZnF615 gene were methylated in ovaries and embryos. Knockout of ZnF615 using CRISPR/Cas9 gene editing decreased the hatching rate and egg number to levels similar to that of Dnmt1 knockout. Analysis of the ZnF615 methylation rate revealed that the DNA methylation pattern in the parent ovary was maintained and doubled in the offspring embryo. Thus, Dnmt1-mediated intragenic DNA methylation of the transcription factor ZnF615 enhances its expression to ensure ovarian and embryonic development.

The insect brain is the central part of the neurosecretory system, which controls morphology, physiology, and behavior during the insect's lifecycle. Lepidoptera are holometabolous insects, and their brains develop during the larval period and metamorphosis into the adult form. As the only fully domesticated insect, the Lepidoptera silkworm Bombyx mori experienced changes in larval brain morphology and certain behaviors during the domestication process. Hormonal regulation in insects is a key factor in multiple processes. However, how juvenile hormone (JH) signals regulate brain development in Lepidoptera species, especially in the larval stage, remains elusive. We recently identified the JH receptor Methoprene tolerant 1 ( Met1 ) as a putative domestication gene. How artificial selection on Met1 impacts brain and behavioral domestication is another important issue addressing Darwin's theory on domestication. Here, CRISPR/Cas9-mediated knockout of Bombyx Met1 caused developmental retardation in the brain, unlike precocious pupation of the cuticle. At the whole transcriptome level, the ecdysteroid (20-hydroxyecdysone, 20E) signaling and downstream pathways were overactivated in the mutant cuticle but not in the brain. Pathways related to cell proliferation and specialization processes, such as extracellular matrix (ECM)-receptor interaction and tyrosine metabolism pathways, were suppressed in the brain. Molecular evolutionary analysis and in vitro assay identified an amino acid replacement located in a novel motif under positive selection in B . mori , which decreased transcriptional binding activity. The B. mori MET1 protein showed a changed structure and dynamic features, as well as a weakened co-expression gene network, compared with B . mandarina . Based on comparative transcriptomic analyses, we proposed a pathway downstream of JH signaling (i.e., tyrosine metabolism pathway) that likely contributed to silkworm larval brain development and domestication and highlighted the importance of the biogenic amine system in larval evolution during silkworm domestication.