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Two Gram-stain positive, aerobic, short-rod-shaped, catalase-positive, oxidase-negative and non-motile strains, designated YIM 101343T and YIM 101645T, were isolated from faeces of Hylobates hoolock and Lemur catta, respectively. The results of 16S rRNA gene analysis indicated that both represented members of the genus Corynebacterium, and they shared a similarity of 98.0â% with each other. Corynebacterium marinum DSM 44953T showed the highest similarity with both strains YIM 101343T (99.0â%) and YIM 101645T (97.3â%). The results of phylogenetic analysis based on 16S rRNA gene indicated that strain YIM 101343T formed a cluster with C. marinum DSM 44953T and Corynebacterium comes 2019T, strain YIM 101645T formed a cluster with Corynebacterium halotolerans YIM 70093T, and the two clusters were neighbours. The genomic size of strain YIM 101343T was 3068751 bp and that of strain YIM 101645T was 3169714 bp. The dDDH, ANI and AAI values among strains YIM 101343T, YIM 101645T and the closely related species indicated that the two isolates represented two different novel species. Both strains contained meso-diaminopimelic acid and short-chain mycolic acids, and the major menaquinones were MK-9(H2) and MK-8(H2). The major polar lipids of the two strains were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannoside. The major fatty acids (>10â%) of both strains were C16â:â0, summed feature 4 and C18â:â1ω9c, but C17â:â1 ω8c was only present as a major component in YIM 101645T . In addition, phenotypic and some chemotaxonomic characteristics of strains YIM 101343T, YIM 101645T and the closely related species were different. Thus, strains YIM 101343T and YIM 101645T should represent two novel species of the genus Corynebacterium, for which the names Corynebacterium hylobatis sp. nov. and Corynebacterium lemuris sp. nov. are proposed, respectively. The type strains are YIM 101343T (=DSM 45970T=CCTCC AB 2013221T) and YIM 101645T (=BCRC 16963T=CCTCC AB 2013281T=KCTC 39868T).
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Ácidos Graxos , Fosfolipídeos , Animais , Ácidos Graxos/química , Fosfolipídeos/análise , Filogenia , RNA Ribossômico 16S/genética , DNA Bacteriano/genética , Técnicas de Tipagem Bacteriana , Composição de Bases , Análise de Sequência de DNA , Corynebacterium/genética , Primatas , Fezes/microbiologiaRESUMO
Using nanotechnology to develop new formulations of pesticides is considered a possible option in enhancing the efficiency, safety, and photostability of pesticides under various climatic conditions. In the present study, two novel nanoformulations (NFs) were successfully prepared based on nano-delivery systems for emamectin benzoate (EMB) by loading it on cellulose nanocrystals (CNCs) and silicon dioxide nanoparticles (SNPs) as carriers through a freeze-drying method. The synthesized nanoformulations were examined using field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and dynamic light scattering (DLS). The results showed that SNPs and CNCs had a loading efficiency of 43.31% and 15.04% (w/w) for EMB, respectively, and could effectively protect EMB from photolysis under UV radiation. The LC50 values for EMB + SNPs, EMB + CNCs, and EMB commercial formulation against Phenacoccus solenopsis were 0.01, 0.05, and 0.31 µg/mL, respectively, indicating that both NFs were more effective than the EMB commercial formulation. This work seeks to develop new nano-carriers for potential applications of pesticides in plant protection, which will reduce the recommended dose of pesticides and thereby decrease the amount of pesticide residue in food and the environment.
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Hemípteros/efeitos dos fármacos , Ivermectina/análogos & derivados , Nanopartículas/química , Animais , Celulose/química , Hemípteros/patogenicidade , Ivermectina/síntese química , Ivermectina/química , Ivermectina/farmacologia , Microscopia Eletrônica de Transmissão , Nanopartículas/ultraestrutura , Controle de Pragas/métodos , Dióxido de Silício/química , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
Pitaya contains various types of polyphenols, flavonoid and vitamins which are beneficial for health and it is among the most important commercial tropical fruits worldwide. Endophytic bacteria might be beneficial for plant growth and yield. However, bacterial diversity in pitaya is poorly characterized. In this study, fruits of white and red pitayas from three different origins (Thailand, Vietnam and China) were chosen for endophytic bacteria diversity investigation by using Illumina HiSeq second-generation high-throughput sequencing technology. Large number of endophytic bacteria were detected and 22 phyla, 56 classes, 81 orders, 122 families and 159 genera were identified. Endophytic bacteria diversity was uneven among pitaya fruits from different origins and bacteria structure was different between white pitaya group and red pitaya group. Phylum Bacteroidetes, classes Bacteroidia and Coriobacteriia, orders Bacteroidales and Coriobacteriales, families Prevotellaceae, Bacteroidaceae, Ruminococcaceae, Paraprevotellaceae, Rikenellaceae, Alcaligenaceae and Coriobacteriaceae, genera Prevotella, Bacteroides, Roseburia, Faecalibacterium and Sutterella were statistically significant different species (P < 0.05) between white and red pitayas. These findings might be useful for growth improvement, fruit preservation and processing of different pitaya species from different origins.
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Bactérias/classificação , Endófitos/classificação , Frutas/microbiologia , Variação Genética , Cactaceae/microbiologia , Geografia , Sequenciamento de Nucleotídeos em Larga Escala , Filogenia , Clima TropicalRESUMO
BACKGROUND: Simple sequence repeats (SSR), also called microsatellites, have been widely used as genetic markers, and have been extensively studied in some model insects. At present, the genomes of more than 100 insect species are available. However, the features of SSRs in most insect genomes remain largely unknown. RESULTS: We identified 15.01 million SSRs across 136 insect genomes. The number of identified SSRs was positively associated with genome size in insects, but the frequency and density per megabase of genomes were not. Most insect SSRs (56.2-93.1%) were perfect (no mismatch). Imperfect (at least one mismatch) SSRs (average length 22-73 bp) were longer than perfect SSRs (16-30 bp). The most abundant insect SSRs were the di- and trinucleotide types, which accounted for 27.2% and 22.0% of all SSRs, respectively. On average, 59.1%, 36.8%, and 3.7% of insect SSRs were located in intergenic, intronic, and exonic regions, respectively. The percentages of various types of SSRs were similar among insects from the same family. However, they were dissimilar among insects from different families within orders. We carried out a phylogenetic analysis using the SSR frequencies. Species from the same family were generally clustered together in the evolutionary tree. However, insects from the same order but not in the same family did not cluster together. These results indicated that although SSRs undergo rapid expansions and contractions in different populations of the same species, the general genomic features of insect SSRs remain conserved at the family level. CONCLUSION: Millions of insect SSRs were identified and their genome features were analyzed. Most insect SSRs were perfect and were located in intergenic regions. We presented evidence that the variance of insect SSRs accumulated after the differentiation of insect families.
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Sequência Conservada/genética , Genoma de Inseto/genética , Genômica , Repetições de Microssatélites/genética , Animais , Motivos de Nucleotídeos/genéticaRESUMO
Recently location based services (LBS) have become increasingly popular in indoor environments. Among these indoor positioning techniques providing LBS, a fusion approach combining WiFi-based and pedestrian dead reckoning (PDR) techniques is drawing more and more attention of researchers. Although this fusion method performs well in some cases, it still has some limitations, such as heavy computation and inconvenience for real-time use. In this work, we study map information of a given indoor environment, analyze variations of WiFi received signal strength (RSS), define several kinds of indoor landmarks, and then utilize these landmarks to correct accumulated errors derived from PDR. This fusion scheme, called Landmark-aided PDR (LaP), is proved to be light-weight and suitable for real-time implementation by running an Android application designed for the experiment. We compared LaP with other PDR-based fusion approaches. Experimental results show that the proposed scheme can achieve a significant improvement with an average accuracy of 2.17 m.
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Native ants have long been considered for their potential to suppress the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), a highly invasive and destructive species. However, the knowledge in this field is limited to behavioral observations of a few related native ants. In this study, by setting up a series of ant combinations of three native ants, i.e., Monomorium chinense Santschi, the robust crazy ant Nylanderia bourbonica Forel, and Iridomyrmex anceps Roger, with S. invicta, we observed the aggression levels and mortality rates. Using baited vials, we also investigated the abundance of native ants in four types of habitats in Eastern China that are preferred by S. invicta (woodland, green belts on roadsides, grassland, and farmland), as well as their seasonal abundance when co-existing with S. invicta and their spatial distribution before and after control of S. invicta. We found that M. chinense and N. bourbonica show a degree of aggression towards S. invicta and can kill substantial proportions of S. invicta under laboratory conditions, but I. anceps does not. Both M. chinense and N. bourbonica can occur in each type of habitat investigated and are more abundant in green belts (particularly lawns with turf) and grasslands relative to other habitats. In grasslands with S. invicta, M. chinense maintained a low density before early July; however, its abundance increased thereafter and reached a peak in September. N. bourbonica also had a low density early in the season and increased steadily from April. Its abundance began to decrease substantially from November. In grasslands invaded by S. invicta, both M. chinense and N. bourbonica were restricted to sites close to the margins before S. invicta was controlled; however, they spread to a larger range within a few weeks after control of S. invicta. In conclusion, M. chinense and N. bourbonica have the potential to suppress S. invicta invasion in habitats that are abundant with these two native ants.
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HYPOTHESIS: Metal-organic frameworks (MOFs) have been widely studied for Cr(VI) adsorption in water. Theoretically, numerous MOFs can be synthesised by assembling diverse metals and ligands. However, the traditional manual experimentation for screening high-performance MOFs is resource-intensive and inefficient. EXPERIMENTS: A screening strategy for MOFs based on machine learning was proposed for the adsorption and removal of Cr(VI) from water. By collecting the characteristics of MOFs and the experimental parameters of Cr(VI) adsorption from the literature, a dataset was constructed to predict the adsorption performance. Among the six regression models, the model trained by the extreme gradient boosted tree algorithm had the best performance and was used to simulate the adsorption and screen potential high-performance adsorbents. FINDINGS: Structure-property analysis indicated that prepared MOF adsorbents with properties of 0.37 < largest cavity diameter < 0.71 nm, 0.18 < pore volume < 0.57 cm3/g, 412 < specific surface area < 1588 m2/g, 0.43 < void fraction < 0.62 will achieve enhanced adsorption of Cr(VI) in water. High-performance adsorbents were successfully screened using a combination of machine-learning prediction and analysis. Experiments were conducted to verify the exceptional adsorption capacity of UiO-66 and MOF-801. This method effectively identified adsorbents and accelerated the development of new MOF adsorbents for contaminant removal, providing a novel approach for the discovery of superior adsorbents.
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Beneficial fungi are well known for their contribution to insects' adaptation to diverse habitats. However, where insect-associated fungi reside and the underlying mechanisms of insect-fungi interaction are not well understood. Here, we show a pellet-like structure on the legs of mealybugs, a group of economically important insect pests. This at-leg pellet, formed by mealybugs feeding on tomato but not by those on cotton, potato, or eggplant, originates jointly from host secretions and mealybug waxy filaments. A fungal strain, Penicillium citrinum, is present in the pellets and it colonizes honeydew. P. citrinum can inhibit mealybug fungal pathogens and is highly competitive in honeydew. Compounds within the pellets also have inhibitory activity against mealybug pathogens. Further bioassays suggest that at-leg pellets can improve the survival rate of Phenacoccus solenopsis under pathogen pressure, increase their sucking frequency, and decrease the defense response of host plants. Our study presents evidences on how a fungi-associated at-leg pellet provides multiple protections for mealybugs through suppressing pathogens and host defense, providing new insights into complex insect × fungi × plant interactions and their coevolution.
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Hemípteros , Penicillium , Penicillium/fisiologia , Animais , Hemípteros/microbiologia , Hemípteros/fisiologiaRESUMO
Paternal genome elimination (PGE) is an intriguing but poorly understood reproductive strategy in which females are typically diploid, but males lose paternal genomes. Paternal genome heterochromatin (PGH) occurs in arthropods with germline PGE, such as the mealybug, coffee borer beetles, and booklice. Here, we present evidence that PGH initially occurs during early embryo development at around 15 h post-mating (hpm) in the cotton mealybug, Phenacoccus solenopsis Tinsley. Transcriptome analysis followed by qPCR validation indicated that six histone lysine methyltransferase (KMT) genes are predominantly expressed in adult females. We knocked down these five genes through dsRNA microinjection. We found that downregulation of two KMT genes, PsEZH2-X1 and PsEHMT1, resulted in a decrease of heterochromatin-related methylations, including H3K27me1, H3K27me3, and H3K9me3 in the ovaries, fewer PGH male embryos, and reduced male offspring. For further confirmation, we obtained two strains of transgenic tobacco highly expressing dsRNA targeting PsEZH2-X1 and PsEHMT1, respectively. Similarly, fewer PGH embryos and fewer male offspring were observed when feeding on these transgenic tobacco plants. Overall, we present evidence that PsEZH2-X1 and PsEHMT1 have essential roles in male embryo survival by regulating PGH formation in cotton mealybugs.
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Desenvolvimento Embrionário , Hemípteros , Histona-Lisina N-Metiltransferase , Animais , Masculino , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Feminino , Desenvolvimento Embrionário/genética , Hemípteros/genética , Hemípteros/enzimologia , Hemípteros/embriologia , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Plantas Geneticamente Modificadas/genéticaRESUMO
The intricate evolutionary dynamics of endosymbiotic relationships result in unique characteristics among the genomes of symbionts, which profoundly influence host insect phenotypes. Here, we investigated an endosymbiotic system in Phenacoccus solenopsis, a notorious pest of the subfamily Phenacoccinae. The endosymbiont, "Candidatus Tremblaya phenacola" (T. phenacola PSOL), persisted throughout the complete life cycle of female hosts and was more active during oviposition, whereas there was a significant decline in abundance after pupation in males. Genome sequencing yielded an endosymbiont genome of 221.1 kb in size, comprising seven contigs and originating from a chimeric arrangement between betaproteobacteria and gammaproteobacteria. A comprehensive analysis of amino acid metabolic pathways demonstrated complementarity between the host and endosymbiont metabolism. Elimination of T. phenacola PSOL through antibiotic treatment significantly decreased P. solenopsis fecundity. Weighted gene coexpression network analysis demonstrated a correlation between genes associated with essential amino acid synthesis and those associated with host meiosis and oocyte maturation. Moreover, altering endosymbiont abundance activated the host mechanistic target of rapamycin pathway, suggesting that changes in the amino acid abundance affected the host reproductive capabilities via this signal pathway. Taken together, these findings demonstrate a mechanism by which the endosymbiont T. phenacola PSOL contributed to high fecundity in P. solenopsis and provide new insights into nutritional compensation and coevolution of the endosymbiotic system.
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Betaproteobacteria , Gammaproteobacteria , Hemípteros , Animais , Masculino , Feminino , Sirolimo/metabolismo , Betaproteobacteria/genética , Gammaproteobacteria/genética , Hemípteros/microbiologia , Reprodução , Aminoácidos/metabolismo , SimbioseRESUMO
There is increasing evidence that force impacts almost every aspect of cells and tissues in physiology and disease including gene regulation. However, the molecular pathway of force transmission from the nuclear lamina to the chromatin remain largely elusive. Here we employ two different approaches of a local stress on cell apical surface via an RGD (Arg-Gly-Asp)-coated magnetic bead and whole cell deformation at cell basal surface via uniaxial or biaxial deformation of a fibronectin-coated flexible polydimethylsiloxane substrate. We find that nuclear protein LAP2ß mediates force transmission from the nuclear lamina to the chromatin. Knocking down LAP2ß increases spontaneous movements of the chromatin by reducing tethering of the chromatin and substantially inhibits the magnetic bead-stress or the substrate-deformation induced chromatin domain stretching and the ensuing dihydrofolate reductase (DHFR) gene upregulation. Analysis of DHFR gene-containing chromatin domain alignments along or perpendicular to the direction of the stretching/compressing reveals that the chromatin domain must be stretched and not compressed in order for the gene to be rapidly upregulated. Together these results suggest that external-load induced rapid transcription upregulation originates from chromatin domain stretching but not compressing and depends on the molecular force transmission pathway of LAP2ß. STATEMENT OF SIGNIFICANCE: How force regulates gene expression has been elusive. Here we show that the orientation of the chromatin domain relative to the stress direction is crucial in determining if the chromatin domain will be stretched or compressed in response to a cell surface loading. We also show that nuclear protein Lap2b is a critical molecule that mediates force transmission from the nuclear laminar to the chromatin to regulate gene transcription. This study reveals the molecular force transmission pathway for force-induced gene regulation.
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Cromatina , Proteínas de Ligação a DNA , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Proteínas de Membrana/química , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismoRESUMO
Digestion and absorption of old cuticles during insect molting are necessary for new cuticle formation, during which complicated enzyme catalysis is essential. To date, a few carboxypeptidases, aminopeptidases and serine proteases (mostly trypsins) connected with cuticle digestion, zymogen activation and histological differentiation during the ecdysis of lepidopteran, dipteran and hymenopteran insects have been identified. However, little is known about these proteins in hemimetabolous insects. In this study, we identified 33 candidate trypsin and trypsin-like homologs, 14 metallocarboxypeptidase and 32 aminopeptidase genes in the brown planthopper Nilaparvata lugens, a hemipteran rice pest. Among the proteins encoded by these genes, 9 trypsin-like proteases, 3 metallocarboxypeptidases and 1 aminopeptidase were selected as potential procuticle hydrolases by bioinformatics analysis and in vivo validation. RNA interference targeting these genes demonstrated that 3 trypsin-like proteases (NlTrypsin-8, NlTrypsin-29 and NlTrypsin-32) genes and 1 metallocarboxypeptidase (NlCpB) gene were found to be essential for ecdysis in N. lugens; specifically, gene silencing led to incomplete cuticle degradation and arrested ecdysis, causing lethal morphological phenotype acquisition. Spatiotemporal expression profiling by quantitative PCR and western blotting revealed their specific expression in the integument and their periodic expression during each stadium, with a peak before ecdysis and eclosion. Transmission electron microscopy demonstrated corresponding ultrastructural defects after RNAi targeting, with NlCpB-silenced specimens having the most undigested old procuticles. Immunohistochemical staining revealed that NlTrypsin-8, NlTrypsin-29 and NlCpB were predominantly located in the exuvial space. This research further adds to our understanding of proteases and its potential role in insect ecdysis.
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Hemípteros , Muda , Animais , Tripsina/metabolismo , Muda/genética , Hemípteros/metabolismo , Serina Proteases/metabolismo , Interferência de RNA , Aminopeptidases/genética , Aminopeptidases/metabolismo , Proteínas de Insetos/metabolismoRESUMO
Lattice structures are a group of cellular materials composed of regular repeating unit cells. Due to their extraordinary mechanical properties, such as specific mechanical strength, ultra-low density, negative Poisson's ratio, etc., lattice structures have been widely applied in the fields of aviation and aerospace, medical devices, architecture, and automobiles. Hybrid additive manufacturing (HAM), an integrated manufacturing technology of 3D printing processes and other complementary processes, is becoming a competent candidate for conveniently delivering lattice structures with multifunctionalities, not just mechanical aspects. This work proposes a HAM technology that combines vat photopolymerization (VPP) and electroless plating process to fabricate smart metal-coated lattice structures. VPP 3D printing process is applied to create a highly precise polymer lattice structure, and thereafter electroless plating is conducted to deposit a thin layer of metal, which could be used as a resistive sensor for monitoring the mechanical loading on the structure. Ni-P layer and copper layer were successfully obtained with the resistivity of 8.2×10-7Ωâ m and 2.0 ×10-8 Ωâ m, respectively. Smart lattice structures with force-loading self-sensing functionality are fabricated to prove the feasibility of this HAM technology for fabricating multifunctional polymer-metal lattice composites.
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Lilium primulinum var. burmanicum (W. W. Smith) Stearn 1948 is an ornamental and medicinal plant that has an extremely limited distribution in Yunnan, China. Here, we obtained the complete plastome of L. primulinum var. burmanicum via next-generation sequencing, and conducted phylogenomic analyses with existing species from Lilium. The total length of L. primulinum var. burmanicum was 152,206 bp with a typical quadripartite structure. The whole plastome contained a pair of inverted repeats (IRa/IRb; 26,399 bp) which divided a large single-copy (LSC; 81,854 bp) and a small single-copy (SSC; 17,563 bp). The average GC content among the whole plastome sequence and the LSC, SSC, and IR regions were 37%, 34.8%, 30.6%, and 42.5%, respectively. There were 134 genes detected from the whole plastome sequence, including 87 protein-coding genes, 39 tRNAs, and 8 rRNAs. Phylogenetic analyses using maximum likelihood showed congruent results that L. primulinum var. burmanicum together with L. primulinum var. ochraceum formed a single branch. These results demonstrate a close relationship between these variation species. The newly characterized chloroplast genome presented here will provide essential data for further phylogenomic analyses of the intraspecific relationship among Lilium species and for conservation genetics research of L. primulinum var. burmanicum.
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Mealybugs are highly aggressive to a diversity of plants. The waxy layer covering the outermost part of the integument is an important protective defense of these pests. However, the molecular mechanisms underlying wax biosynthesis in mealybugs remain largely unknown. Here, we analyzed multi-omics data on wax biosynthesis by the cotton mealybug, Phenacoccus solenopsis Tinsley, and found that a fatty acyl-CoA reductase (PsFAR) gene, which was highly expressed in the fat bodies of female mealybugs, contributed to wax biosynthesis by regulating the production of the dominant chemical components of wax, cuticular hydrocarbons (CHCs). RNA interference (RNAi) against PsFAR by dsRNA microinjection and allowing mealybugs to feed on transgenic tobacco expressing target dsRNA resulted in a reduction of CHC contents in the waxy layer, and an increase in mealybug mortality under desiccation and deltamethrin treatments. In conclusion, PsFAR plays crucial roles in the wax biosynthesis of mealybugs, thereby contributing to their adaptation to water loss and insecticide stress.
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Hemípteros , Inseticidas , Animais , Hemípteros/genética , Aldeído Oxirredutases/genética , Gossypium/genética , ÁguaRESUMO
Heat shock 70kDa proteins (HSP70s) and their cochaperones DNAJs are ubiquitous molecular chaperones, which function as the "HSP70/DNAJ machinery" in a myriad of biological processes. At present, a number of HSP70s have been classified in many species, but studies on DNAJs, especially in insects, are lacking. Here, we first systematically identified and characterized the HSP70 and DNAJ family members in the brown planthopper (BPH), Nilaparvata lugens, a destructive rice pest in Asia. A total of nine HSP70 and 31 DNAJ genes were identified in the BPH genome. Sequence and phylogenetic analyses revealed the high diversity of the NlDNAJ family. Additionally, spatio-temporal expression analysis showed that most NlHSP70 and NlDNAJ genes were highly expressed in the adult stage and gonads. Furthermore, RNA interference (RNAi) revealed that seven NlHSP70s and 10 NlDNAJs play indispensable roles in the nymphal development, oogenesis, and female fertility of N. lugens under physiological growth conditions; in addition, one HSP70 (NlHSP68) was found to be important in the thermal tolerance of eggs. Together, our results in this study shed more light on the biological roles of HSP70/DNAJ in regulating life cycle, coping with environmental stresses, and mediating the interactions within, or between, the two gene families in insects.
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Proteínas de Choque Térmico/genética , Hemípteros/genética , Animais , Ásia , Fertilidade/genética , Chaperonas Moleculares/genética , Ninfa/genética , Oogênese/genética , Oryza/parasitologia , Filogenia , Interferência de RNA/fisiologia , Estresse Fisiológico/genéticaRESUMO
Using smart nanopesticide formulations based on nanomaterials can offer promising potential applications for decreasing pesticide residues and their effects on human health and the environment. In this study, a novel nanoformulation (NF) of thiamethoxam (TMX) was fabricated using the solvent evaporation method through loading TMX on cellulose nanocrystals (CNCs) as the carrier. The synthesized TMX-CNCs was investigated through different techniques, such as Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), and thermogravimetric analysis (TGA). The results revealed that the loading efficiency and entrapment efficiency were 18.7% and 83.7 ± 1.8% for TMX, respectively. The prepared nanoformulation (TMX-CNCs) had a width of 7-14 nm and a length of 85-214 nm with a zeta potential of -23.6 ± 0.3 mV. The drug release behavior study exhibited that the release of TMX from TMX-loaded CNCs was good and sustained. Furthermore, bioassay results showed that the insecticidal activity of TMX-CNCs against Phenacoccus solenopsis was significantly superior to that of the technical and commercial formulation, as indicated by the lower LC50 value. The results indicate that the TMX nanoformulation has great potential for application in agriculture for pest control.
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Hsp90 (heat shock protein 90) chaperone machinery is considered to be a key regulator of proteostasis under both physiological and stress growth conditions in eukaryotic cells. The high conservation of both the sequence and function of Hsp90 allows for the utilization of various species to explore new phenotypes and mechanisms. In this study, three Hsp90 homologs were identified in the brown planthopper (BPH), Nilaparvata lugens: cytosolic NlHsp90, endoplasmic reticulum (ER) NlGRP94 and mitochondrial NlTRAP1. Sequence analysis and phylogenetic construction showed that these proteins belonged to distinct classes consistent with the predicted localization and suggested an evolutionary relationship between NlTRAP1 and bacterial HtpG (high-temperature protein G). Temporospatial expression analyses showed that NlHsp90 was inducible under heat stress throughout the developmental stage, while NlGRP94 was only induced at the egg stage. All three genes had a significantly high transcript level in the ovary. The RNA interference-mediated knockdown of NlHsp90 its essential role in nymph development and oogenesis under physiological conditions. NlGRP94 was also required during the early developmental stage and played a crucial role in oogenesis, fecundity and late embryogenesis. Notably, we first found that NlHsp90 and NlGRP94 were likely involved in the cuticle structure of female BPH. Together, our research revealed multifunctional roles of Hsp90s in the BPH.
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Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Choque Térmico/metabolismo , Hemípteros/metabolismo , Temperatura Alta , Ninfa/metabolismo , Oogênese , Animais , Feminino , Fertilidade , Proteínas de Choque Térmico/antagonistas & inibidores , Proteínas de Choque Térmico/genética , Hemípteros/genética , Hemípteros/crescimento & desenvolvimento , Ninfa/genética , Ninfa/crescimento & desenvolvimento , Filogenia , Interferência de RNARESUMO
The cotton mealybug, Phenacoccus solenopsis, is an invasive pest that can cause massive damage to many host plants of agricultural importance. P. solenopsis is highly polyphagous, and shows extreme sexual dimorphism between males and females. The functions of DNA methyltransferase (DNMT) enzymes in the cotton mealybug have not been well studied. Here, we carried out an investigation of DNMTs in cotton mealybug to study their roles in sexual dimorphism. We found that the cotton mealybug has two copies of PsDnmt1, but Dnmt3 is absent. We then amplified the full-length cDNAs of PsDnmt1A (2,225 bp) and PsDnmt1B (2,862 bp) using rapid amplification cDNA ends (RACE). Quantitative reverse transcriptase PCR shows that both PsDnmt1A and PsDnmt1B are highly expressed in adult males, while the expression of PsDnmt1B is 30-fold higher in gravid females than in virgin females. We knocked down PsDnmt1A and PsDnmt1B with small interfering RNAs (siRNAs), and both genes were successfully down-regulated after 24 h or 72 h in adult females and pupa (t-test, p < 0.05). Down-regulating the expression of these two DNMT genes led to offspring lethality and abnormal body color in adult females. Furthermore, the silencing of PsDnmt1B induced abnormal wing development in emerged adult males. Our results provide evidence that PsDnmt1 plays a crucial role in regulating sexual dimorphism in the cotton mealybug.
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Mealybugs (Hemiptera: Pseudococcidae) are economically important agricultural pests with several compelling biological phenomena including paternal genome elimination (PGE). However, limited high-quality genome assemblies of mealybugs hinder a full understanding of this striking and unusual biological phenomenon. Here, we generated a chromosome-level genome assembly of cotton mealybug, Phenacoccus solenopsis, by combining Illumina short reads, PacBio long reads and Hi-C scaffolding. The assembled genome was 292.54 Mb with a contig N50 of 489.8 kb and a scaffold N50 of 49.0 Mb. Hi-C scaffolding assigned 84.42% of the bases to five chromosomes. A total of 110.75 Mb (37.9%) repeat sequences and 11,880 protein-coding genes were predicted. The completeness of the genome assembly was estimated to be 95.5% based on BUSCO genes. In addition, 27,086 (95.3%) full-length PacBio transcripts were uniquely mapped to the assembled scaffolds, suggesting the high quality of the genome assembly. We showed that cotton mealybugs lack differentiated sex chromosomes by analysing genome resequencing data of males and females. DAPI staining confirmed that one chromosome set in males becomes heterochromatin at an early embryo stage. Chromatin immunoprecipitation assays with sequencing analysis demonstrated that the epigenetic modifications H3K9me3 and H3K27me3 are distributed across the whole genome in males, suggesting that these two modifications might be involved in maintaining heterochromatin status. Both markers were more likely to be distributed in repeat regions, while H3K27me3 had higher overall enrichment. Our results provide a valuable genomic resource and shed new light on the genomic and epigenetic basis of PGE in cotton mealybugs.