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1.
J Immunol ; 207(1): 200-209, 2021 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-34162722

RESUMEN

Melanization and encapsulation are prominent defense responses against microbes detected by pattern recognition receptors of their host insects. In the ghost moth Thitarodes xiaojinensis, an activated immune system can melanize and encapsulate the fungus Cordyceps militaris However, these responses were hardly detected in the host hemolymph postinfection of another fungus Ophiocordyceps sinensis The immune interaction between O. sinensis and the host remains largely unknown, which hinders the artificial cultivation of Chinese cordyceps. We found that T. xiaojinensis ß-1,3-glucan recognition protein-1 (ßGRP1) was needed for prophenoloxidase activation induced by C. militaris Failure of ßGRP1 to recognize O. sinensis is a primary reason for the lack of melanization in the infected host. Lyticase or snailase treatment combined with binding and immunofluorescence detection showed the existence of a protective layer preventing the fungus from ßGRP1 recognition. Coimmunoprecipitation and mass spectrometry analysis indicated that ßGRP1 interacted with immulectin-8 (IML8) via binding to C. militaris IML8 promotes encapsulation. This study suggests the roles of T. xiaojinensis ßGRP1 and IML8 in modulating immune responses against C. militaris Most importantly, the data indicate that O. sinensis may evade melanization by preventing ßGRP1 recognition.


Asunto(s)
Cordyceps/inmunología , Proteínas de Insectos/inmunología , Mariposas Nocturnas/inmunología , Animales , Mariposas Nocturnas/microbiología
2.
Proc Natl Acad Sci U S A ; 117(38): 23581-23587, 2020 09 22.
Artículo en Inglés | MEDLINE | ID: mdl-32900946

RESUMEN

Proteolytic activation of phenoloxidase (PO) and the cytokine Spätzle during immune responses of insects is mediated by a network of hemolymph serine proteases (HPs) and noncatalytic serine protease homologs (SPHs) and inhibited by serpins. However, integration and conservation of the system and its control mechanisms are not fully understood. Here we present biochemical evidence that PO-catalyzed melanin formation, Spätzle-triggered Toll activation, and induced synthesis of antimicrobial peptides are stimulated via hemolymph (serine) protease 5 (HP5) in Manduca sexta Previous studies have demonstrated a protease cascade pathway in which HP14 activates proHP21; HP21 activates proPAP2 and proPAP3, which then activate proPO in the presence of a complex of SPH1 and SPH2. We found that both HP21 and PAP3 activate proHP5 by cleavage at ESDR176*IIGG. HP5 then cleaves proHP6 at a unique site of LDLH112*ILGG. HP6, an ortholog of Drosophila Persephone, activates both proHP8 and proPAP1. HP8 activates proSpätzle-1, whereas PAP1 cleaves and activates proPO. HP5 is inhibited by Manduca sexta serpin-4, serpin-1A, and serpin-1J to regulate its activity. In summary, we have elucidated the physiological roles of HP5, a CLIPB with unique cleavage specificity (cutting after His) that coordinates immune responses in the caterpillar.


Asunto(s)
Hemolinfa , Proteínas de Insectos , Manduca , Serina Proteasas , Animales , Hemolinfa/enzimología , Hemolinfa/inmunología , Proteínas de Insectos/inmunología , Proteínas de Insectos/metabolismo , Manduca/enzimología , Manduca/inmunología , Manduca/metabolismo , Serina Proteasas/inmunología , Serina Proteasas/metabolismo , Transducción de Señal , Receptores Toll-Like/inmunología , Receptores Toll-Like/metabolismo
3.
Opt Lett ; 47(6): 1502-1505, 2022 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-35290349

RESUMEN

The development of laser-induced graphene (LIG) has been regarded as an effective method for satisfying the substantial requirements for the scalable fabrication of graphene-based electrode materials. Despite the rapid progress in fabricating LIG-based supercapacitors, the incompatibility between material modification and the device planarization process remains a challenging problem to be resolved. In this study, we demonstrate the attributes of novel LIG-MXene (LIG-M) composite electrodes for flexible planar supercapacitors fabricated by direct laser writing (DLW) of MXene-coated polyimide (PI) films. During the DLW process, PI was transformed into LIG, while MXene was simultaneously introduced to produce LIG-M. Combining the porous structure of LIG and the high conductivity of MXene, the as-prepared LIG-M-based supercapacitor exhibited superior specific capacitance, five times higher than that of the pristine LIG-based supercapacitor. The enhanced capacitance of LIG-M also benefited from the pseudocapacitive performance of the abundant active sites offered by MXene. Moreover, the planar LIG-M-based device delivered excellent cycling stability and flexibility. No significant performance degradation was observed after bending tests. Arbitrary electrode patterns could be obtained using the DLW technique. The patterned in-series LIG-M supercapacitor was able to power a light-emitting diode, demonstrating significant potential for practical applications.

4.
Arch Insect Biochem Physiol ; 108(2): e21841, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34468040

RESUMEN

Pathogen-induced host immune responses reduce the efficacy of pathogens used to control pests. However, compared to the well-deciphered immunity system of Drosophila melanogaster, the immunity system of agricultural pests is largely unconfirmed through functional analysis. Beginning to unveil mechanisms of transcription regulation of immune genes in the Asian corn borer, Ostrinia furnacalis, we cloned the complementary DNA (cDNA) of a transcription factor Relish by rapid amplification of cDNA ends. The 3164 bp cDNA, designated Of-Relish, encodes a 956-residue protein. Bioinformatic analysis showed that Of-Relish had a Rel homology domain, a predicted cleavage site between Q409 and L410 , six ankyrin repeats, and a death domain. The response of Of-Relish expression to the Gram-negative bacteria Pseudomonas aeruginosa was sooner and stronger than to the Gram-positive Micrococcus luteus. The antimicrobial peptide genes Attacin and Gloverin had similar expression patterns in response to the infections. Knockdown of Of-Relish led to a decrease in Attacin and Gloverin messenger RNA levels, suggesting that Attacin and Gloverin were regulated by Of-Relish. Together, the results suggested that Of-Relish is a key component of the IMD pathway in O. furnacalis, involved in defense against P. aeruginosa through activation of Attacin and Gloverin.


Asunto(s)
Regulación de la Expresión Génica , Mariposas Nocturnas/inmunología , Proteínas Citotóxicas Formadoras de Poros/metabolismo , Factores de Transcripción/genética , Animales , Proteínas de Drosophila/genética , Genes de Insecto , Inmunidad/genética , Proteínas de Insectos/metabolismo , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Mariposas Nocturnas/genética
5.
Opt Lett ; 44(7): 1714-1717, 2019 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-30933129

RESUMEN

Herein, we report a simple laser holography technology for hierarchically structuring and synchronous photoreduction of graphene oxides (GO), toward the development of efficient graphene-based electrodes for supercapacitor applications in cost effectively manners. Hierarchical micro-nanostructures, formed due to laser treatment induced photoreduction and ablation effect. Interestingly, both the morphology and reduction degree of the laser holography reduced GO (LHRGO) show strong dependence on the laser intensity, providing the feasibility for controlling the micro-nanostructures, chemical composition, and the conductivity of the graphene electrodes. Furthermore, the supercapacitors based on LHRGO show higher capacitance values and better electrochemical performance compared to that based on thermal reduced GO (TRGO) of same reduction level. Photoredution and micro-nanostructuring of GO using laser holography may hold great promise for production of effective carbon-based electrodes towards practical applications in energy storage devices.

6.
Chem Res Toxicol ; 32(9): 1801-1810, 2019 09 16.
Artículo en Inglés | MEDLINE | ID: mdl-31411024

RESUMEN

The single residue mutation of butyrylcholinesterase (BChEG117H) hydrolyzes a number of organophosphosphorus (OP) anticholinesterases. Whereas other BChE active site/proximal mutations have been investigated, none are sufficiently active to be prophylactically useful. In a fundamentally different computer simulations driven strategy, we identified a surface peptide loop (residues 278-285) exhibiting dynamic motions during catalysis and modified it via residue insertions. We evaluated these loop mutants using computer simulations, substrate kinetics, resistance to inhibition, and enzyme reactivation assays using both the choline ester and OP substrates. A slight but significant increase in reactivation was noted with paraoxon with one of the mutants, and changes in KM and catalytic efficiency were noted in others. Simulations suggested weaker interactions between OP versus choline substrates and the active site of all engineered versions of the enzyme. The results indicate that an improvement of OP anticholinesterase hydrolysis through surface loop engineering may be a more effective strategy in an enzyme with higher intrinsic OP compound hydrolase activity.


Asunto(s)
Butirilcolinesterasa/química , Inhibidores de la Colinesterasa/química , Yoduro de Ecotiofato/química , Isoflurofato/química , Paraoxon/química , Biocatálisis , Butirilcolinesterasa/genética , Butirilcolinesterasa/metabolismo , Dominio Catalítico , Inhibidores de la Colinesterasa/metabolismo , Yoduro de Ecotiofato/metabolismo , Hidrólisis , Isoflurofato/metabolismo , Cinética , Simulación de Dinámica Molecular , Mutación , Paraoxon/metabolismo , Unión Proteica , Ingeniería de Proteínas , Termodinámica
7.
Langmuir ; 35(3): 815-823, 2019 01 22.
Artículo en Inglés | MEDLINE | ID: mdl-30563345

RESUMEN

Inspired from fish scales that exhibit unique underwater superoleophobicity, artificial porous membranes featuring similar wettability have been successfully developed for oil-water separation. However, most of the superoleophobic meshes are workable only for underwater oil/water separation and become disabled in air. In this article, we reported the facile fabrication of underwater superoleophobic kraft mesh and demonstrated efficient oil-water separation using kraft mesh origamis. Kraft paper that features porosity, natural hydrophilicity, and relatively high elasticity and tear resistance has been found to be an ideal candidate for developing underwater superoleophobic origami. Direct laser drilling has been employed to make microhole arrays on the kraft paper, forming a flexible mesh. The hydrophilic nature and the hierarchical microstructures that consist of microhole arrays and porous microfiber networks make the resultant kraft mesh superoleophobic underwater, enabling oil-water separation. More importantly, the kraft mesh can retain a large amount of water (2.5 times its weight under dry conditions) owing to its porous and hydrophilic structure. Thus, the wet kraft mesh became a slippery surface for oil droplets when it was taken out of the water. This unique feature makes it possible to directly fish out oil droplets from water using a simple kraft mesh origami. Direct laser drilling of paper mesh for flexible origami may open up a new route to the rational design and fabrication of oil-water separation devices.

8.
Mol Cell Proteomics ; 15(4): 1176-87, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26811355

RESUMEN

Manduca sextais a lepidopteran model widely used to study insect physiological processes, including innate immunity. In this study, we explored the proteomes of cell-free hemolymph from larvae injected with a sterile buffer (C for control) or a mixture of bacteria (I for induced). Of the 654 proteins identified, 70 showed 1.67 to >200-fold abundance increases after the immune challenge; 51 decreased to 0-60% of the control levels. While there was no strong parallel between plasma protein levels and their transcript levels in hemocytes or fat body, the mRNA level changes (i.e.I/C ratios of normalized read numbers) in the tissues concurred with their protein level changes (i.e.I/C ratios of normalized spectral counts) with correlation coefficients of 0.44 and 0.57, respectively. Better correlations support that fat body contributes a more significant portion of the plasma proteins involved in various aspects of innate immunity. Consistently, ratios of mRNA and protein levels were better correlated for immunity-related proteins than unrelated ones. There is a set of proteins whose apparent molecular masses differ considerably from the calculatedMr's, suggestive of posttranslational modifications. In addition, some lowMrproteins were detected in the range of 80 to >300 kDa on a reducing SDS-polyacrylamide gel, indicating the existence of highMrcovalent complexes. We identified 30 serine proteases and their homologs, 11 of which are known members of an extracellular immune signaling network. Along with our quantitative transcriptome data, the protein identification, inducibility, and association provide leads toward a focused exploration of humoral immunity inM. sexta.


Asunto(s)
Inmunidad Innata , Proteínas de Insectos/sangre , Manduca/microbiología , Proteoma/metabolismo , Transcriptoma , Animales , Cuerpo Adiposo/fisiología , Regulación de la Expresión Génica , Hemolinfa/metabolismo , Larva/inmunología , Larva/microbiología , Manduca/crecimiento & desarrollo , Manduca/inmunología
9.
BMC Genomics ; 18(1): 796, 2017 Oct 17.
Artículo en Inglés | MEDLINE | ID: mdl-29041902

RESUMEN

BACKGROUND: Manduca sexta is a large lepidopteran insect widely used as a model to study biochemistry of insect physiological processes. As a part of its genome project, over 50 cDNA libraries have been analyzed to profile gene expression in different tissues and life stages. While the RNA-seq data were used to study genes related to cuticle structure, chitin metabolism and immunity, a vast amount of the information has not yet been mined for understanding the basic molecular biology of this model insect. In fact, the basic features of these data, such as composition of the RNA-seq reads and lists of library-correlated genes, are unclear. From an extended view of all insects, clear-cut tempospatial expression data are rarely seen in the largest group of animals including Drosophila and mosquitoes, mainly due to their small sizes. RESULTS: We obtained the transcriptome data, analyzed the raw reads in relation to the assembled genome, and generated heatmaps for clustered genes. Library characteristics (tissues, stages), number of mapped bases, and sequencing methods affected the observed percentages of genome transcription. While up to 40% of the reads were not mapped to the genome in the initial Cufflinks gene modeling, we identified the causes for the mapping failure and reduced the number of non-mappable reads to <8%. Similarities between libraries, measured based on library-correlated genes, clearly identified differences among tissues or life stages. We calculated gene expression levels, analyzed the most abundantly expressed genes in the libraries. Furthermore, we analyzed tissue-specific gene expression and identified 18 groups of genes with distinct expression patterns. CONCLUSION: We performed a thorough analysis of the 67 RNA-seq datasets to characterize new genomic features of M. sexta. Integrated knowledge of gene functions and expression features will facilitate future functional studies in this biochemical model insect.


Asunto(s)
Perfilación de la Expresión Génica , Manduca/genética , Análisis de Secuencia de ARN , Animales , Codón/genética , Biblioteca de Genes , Genoma de los Insectos/genética , Genómica , Especificidad de Órganos , ARN de Transferencia/genética , Transcripción Genética
10.
Opt Lett ; 42(17): 3403-3406, 2017 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-28957048

RESUMEN

We reported here a facile fabrication of flexible graphene-based field effect transistors (FETs) by sunlight reduction of graphene oxide (GO) as channel material. As a mask-free and chemical-free method, sunlight photoreduction of GO without the use of any complex equipments is simple and green. The resultant FET demonstrated excellent electrical properties (e.g., an optimized Ion/Ioff ratio of 111, hole mobility of 0.17 cm2 V-1 s-1), revealing great potential for development of flexible microelectrics. Additionally, since the reduced GO channel could be fabricated by sunlight treatment between two pre-patterned electrodes, the process features post-fabrication capability, which makes it possible to integrate graphene-based devices with given device structures.

11.
BMC Biol ; 14: 2, 2016 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-26732497

RESUMEN

BACKGROUND: Phenoloxidase (PO)-catalyzed melanization is a universal defense mechanism of insects against pathogenic and parasitic infections. In mosquitos such as Anopheles gambiae, melanotic encapsulation is a resistance mechanism against certain parasites that cause malaria and filariasis. PO is initially synthesized by hemocytes and released into hemolymph as inactive prophenoloxidase (PPO), which is activated by a serine protease cascade upon recognition of foreign invaders. The mechanisms of PPO activation and PO catalysis have been elusive. RESULTS: Herein, we report the crystal structure of PPO8 from A. gambiae at 2.6 Å resolution. PPO8 forms a homodimer with each subunit displaying a classical type III di-copper active center. Our molecular docking and mutagenesis studies revealed a new substrate-binding site with Glu364 as the catalytic residue responsible for the deprotonation of mono- and di-phenolic substrates. Mutation of Glu364 severely impaired both the monophenol hydroxylase and diphenoloxidase activities of AgPPO8. Our data suggested that the newly identified substrate-binding pocket is the actual site for catalysis, and PPO activation could be achieved without withdrawing the conserved phenylalanine residue that was previously deemed as the substrate 'placeholder'. CONCLUSIONS: We present the structural and functional data from a mosquito PPO. Our results revealed a novel substrate-binding site with Glu364 identified as the key catalytic residue for PO enzymatic activities. Our data offered a new model for PPO activation at the molecular level, which differs from the canonical mechanism that demands withdrawing a blocking phenylalanine residue from the previously deemed substrate-binding site. This study provides new insights into the mechanisms of PPO activation and enzymatic catalysis of PO.


Asunto(s)
Anopheles/enzimología , Catecol Oxidasa/química , Catecol Oxidasa/metabolismo , Precursores Enzimáticos/química , Precursores Enzimáticos/metabolismo , Animales , Anopheles/química , Sitios de Unión , Dominio Catalítico , Cristalografía por Rayos X , Simulación del Acoplamiento Molecular , Conformación Proteica , Multimerización de Proteína
12.
Chem Rec ; 16(3): 1244-55, 2016 06.
Artículo en Inglés | MEDLINE | ID: mdl-27062335

RESUMEN

We report herein the engineering of the surface/interface properties of graphene oxide (GO) films by controllable photoreduction treatment. In our recent works, typical photoreduction processes, including femtosecond laser direct writing (FsLDW), laser holographic lithography, and controllable UV irradiation, have been employed to make conductive reduced graphene oxide (RGO) microcircuits, hierarchical RGO micro-nanostructures with both superhydrophobicity and structural color, as well as moisture-responsive GO/RGO bilayer structures. Compared with other reduction protocols, for instance, chemical reduction and thermal annealing, the photoreduction strategy shows distinct advantages, such as mask-free patterning, chemical-free modification, controllable reduction degree, and environmentally friendly processing. These works indicate that the surface and interface engineering of GO through controllable photoreduction of GO holds great promise for the development of various graphene-based microdevices.

13.
BMC Genomics ; 16: 321, 2015 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-26001831

RESUMEN

BACKGROUND: Innate immunity is essential in defending against invading pathogens in invertebrates. The cotton bollworm, Helicoverpa armigera (Hübner) is one of the most destructive lepidopteran pests, which causes enormous economic losses in agricultural production worldwide. The components of the immune system are largely unknown in this insect. The application of entomopathogens is considered as an alternative to the chemical insecticides for its control. However, few studies have focused on the molecular mechanisms of host-pathogen interactions between pest insects and their pathogens. Here, we investigated the immunotranscriptome of H. armigera larvae and examined gene expression changes after pathogen infections. This study provided insights into the potential immunity-related genes and pathways in H. armigera larvae. RESULTS: Here, we adopted a high throughput RNA-seq approach to determine the immunotranscriptome of H. armigera larvae injected with buffer, fungal pathogen Beauveria bassiana, or Gram-negative bacterium Enterobacter cloacae. Based on sequence similarity to those homologs known to participate in immune responses in other insects, we identified immunity-related genes encoding pattern recognition receptors, signal modulators, immune effectors, and nearly all members of the Toll, IMD and JAK/STAT pathways. The RNA-seq data indicated that some immunity-related genes were activated in fungus- and bacterium-challenged fat body while others were suppressed in B. bassiana challenged hemocytes, including the putative IMD and JAK-STAT pathway members. Bacterial infection elevated the expression of recognition and modulator genes in the fat body and signal pathway genes in hemocytes. Although fat body and hemocytes both are important organs involved in the immune response, our transcriptome analysis revealed that more immunity-related genes were induced in the fat body than that hemocytes. Furthermore, quantitative real-time PCR analysis confirmed that, consistent with the RNA-seq data, the transcript abundances of putative PGRP-SA1, Serpin1, Toll-14, and Spz2 genes were elevated in fat body upon B. bassiana infection, while the mRNA levels of defensin, moricin1, and gloverin1 were up-regulated in hemocytes. CONCLUSIONS: In this study, a global survey of the host defense against fungal and bacterial infection was performed on the non-model lepidopteran pest species. The comprehensive sequence resource and expression profiles of the immunity-related genes in H. armigera are acquired. This study provided valuable information for future functional investigations as well as development of specific and effective agents to control this pest.


Asunto(s)
Perfilación de la Expresión Génica/métodos , Inmunidad Innata , Proteínas de Insectos/genética , Mariposas Nocturnas/microbiología , Análisis de Secuencia de ARN/métodos , Animales , Cuerpo Adiposo/inmunología , Cuerpo Adiposo/microbiología , Regulación de la Expresión Génica , Hemocitos/inmunología , Hemocitos/microbiología , Proteínas de Insectos/metabolismo , Larva/inmunología , Larva/microbiología , Mariposas Nocturnas/genética , Mariposas Nocturnas/inmunología , Filogenia
14.
Insect Biochem Mol Biol ; 164: 104048, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38056530

RESUMEN

Phenoloxidase (PO) catalyzed melanization and other insect immune responses are mediated by serine proteases (SPs) and their noncatalytic homologs (SPHs). Many of these SP-like proteins have a regulatory clip domain and are called CLIPs. In most insects studied so far, PO precursors are activated by a PAP (i.e., PPO activating protease) and its cofactor of clip-domain SPHs. Although melanotic encapsulation is a well-known refractory mechanism of mosquitoes against malaria parasites, it is unclear if a cofactor is required for PPO activation. In Anopheles gambiae, CLIPA4 is 1:1 orthologous to Manduca sexta SPH2; CLIPs A5-7, A12-14, A26, A31, A32, E6, and E7 are 11:4 orthologous to M. sexta SPH1a, 1b, 4, and 101, SPH2 partners in the cofactors. Here we produced proCLIPs A4, A6, A7Δ, A12, and activated them with CLIPB9 or M. sexta PAP3. A. gambiae PPO2 and PPO7 were expressed in Escherichia coli for use as PAP substrates. CLIPB9 was mutated to CLIPB9Xa by including a Factor Xa cleavage site. CLIPA7Δ was a deletion mutant with a low complexity region removed. After PAP3 or CLIPB9Xa processing, CLIPA4 formed a high Mr complex with CLIPA6, A7Δ or A12, which assisted PPO2 and PPO7 activation. High levels of specific PO activity (55-85 U/µg for PO2 and 1131-1630 U/µg for PO7) were detected in vitro, indicating that cofactor-assisted PPO activation also occurs in this species. The cleavage sites and mechanisms for complex formation and cofactor function are like those reported in M. sexta and Drosophila melanogaster. In conclusion, these data suggest that the three (and perhaps more) SPHI-II pairs may form cofactors for CLIPB9-mediated activation of PPOs for melanotic encapsulation in A. gambiae.


Asunto(s)
Anopheles , Manduca , Animales , Serina Proteasas/metabolismo , Anopheles/metabolismo , Drosophila melanogaster/metabolismo , Serina Endopeptidasas , Catecol Oxidasa/genética , Catecol Oxidasa/metabolismo , Precursores Enzimáticos/genética , Precursores Enzimáticos/metabolismo , Monofenol Monooxigenasa , Manduca/metabolismo , Proteínas de Insectos/metabolismo , Hemolinfa
15.
Insect Biochem Mol Biol ; 168: 104108, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38552808

RESUMEN

The immune system of Manduca sexta has been well studied to understand molecular mechanisms of insect antimicrobial responses. While evidence supports the existence of major immune signaling pathways in this species, it is unclear how induced production of defense proteins is specifically regulated by the Toll and Imd pathways. Our previous studies suggested that diaminopimelic acid-type peptidoglycans (DAP-PG) from Gram-negative and some Gram-positive bacteria, more than Lys-type peptidoglycans (Lys-PG) from other Gram-positive bacteria, triggers both pathways through membrane-bound receptors orthologous to Drosophila Toll and PGRP-LC. In this study, we produced M. sexta proSpätzle-1 and proSpätzle-2 in Sf9 cells, identified their processing enzymes, and used prophenoloxidase activating protease-3 to activate the cytokine precursors. After Spätzle-1 and -2 were isolated from the reaction mixtures, we separately injected the purified cytokines into larval hemocoel to induce gene transcription in fat body through the Toll pathway solely. On the other hand, we treated a M. sexta cell line with E. coli DAP-PG to only induce the Imd pathway and target gene expression. RNA-Seq analysis of the fat body and cultured cells collected at 0, 6, and 24 h after treatment indicated that expression of diapausin-4, -10, -12, -13, cecropin-2, -4, -5, attacin-5, -11, and lebocin D is up-regulated predominantly via Toll signaling, whereas transcription of cecropin-6, gloverin, lysozyme-1, and gallerimycin-2 is mostly induced by DAP-PG via Imd signaling. Other antimicrobial peptides are expressed in response to both pathways. Transcripts of most Toll-specific genes (e.g., lebocin D) peaked at 6 h, contrasting the gradual increase and plateauing of drosomycin mRNA level at 24-48 h in Drosophila. We also used T (oll)-I (md) ratios to estimate relative contributions of the two pathways to transcriptional regulation of other components of the immune system. The differences in pathway specificity and time course of transcriptional regulation call for further investigations in M. sexta and other insects.


Asunto(s)
Cecropinas , Manduca , Animales , Escherichia coli/genética , Manduca/metabolismo , Peptidoglicano , Cecropinas/metabolismo , Proteínas de Insectos/metabolismo , Citocinas/metabolismo , Drosophila/metabolismo
16.
Front Immunol ; 14: 1244792, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37781370

RESUMEN

Insect phenoloxidases (POs) catalyze phenol oxygenation and o-diphenol oxidation to form reactive intermediates that kill invading pathogens and form melanin polymers. To reduce their toxicity to host cells, POs are produced as prophenoloxidases (PPOs) and activated by a serine protease cascade as required. In most insects studied so far, PPO activating proteases (PAPs) generate active POs in the presence of a high Mr cofactor, comprising two serine protease homologs (SPHs) each with a Gly residue replacing the catalytic Ser of an S1A serine protease (SP). These SPHs have a regulatory clip domain at the N-terminus, like most of the SP cascade members including PAPs. In Drosophila, PPO activation and PO-catalyzed melanization have been examined in genetic analyses but it is unclear if a cofactor is required for PPO activation. In this study, we produced the recombinant cSPH35 and cSPH242 precursors, activated them with Manduca sexta PAP3, and confirmed their predicted role as a cofactor for Drosophila PPO1 activation by MP2 (i.e., Sp7). The cleavage sites and mechanisms for complex formation and cofactor function are highly similar to those reported in M. sexta. In the presence of high Mr complexes of the cSPHs, PO at a high specific activity of 260 U/µg was generated in vitro. To complement the in vitro analysis, we measured hemolymph PO activity levels in wild-type flies, cSPH35, and cSPH242 RNAi lines. Compared with the wild-type flies, only 4.4% and 18% of the control PO level (26 U/µl) was detected in the cSPH35 and cSPH242 knockdowns, respectively. Consistently, percentages of adults with a melanin spot at the site of septic pricking were 82% in wild-type, 30% in cSPH35 RNAi, and 53% in cSPH242 RNAi lines; the survival rate of the control (45%) was significantly higher than those (30% and 15%) of the two RNAi lines. These data suggest that Drosophila cSPH35 and cSPH242 are components of a cofactor for MP2-mediated PPO1 activation, which are indispensable for early melanization in adults.


Asunto(s)
Catecol Oxidasa , Proteínas de Drosophila , Precursores Enzimáticos , Serina Proteasas , Animales , Drosophila melanogaster , Proteínas de Drosophila/genética , Melaninas , Monofenol Monooxigenasa , Serina Endopeptidasas , Serina Proteasas/genética , Catecol Oxidasa/genética , Precursores Enzimáticos/genética
17.
Sci Adv ; 9(51): eadk2756, 2023 Dec 22.
Artículo en Inglés | MEDLINE | ID: mdl-38117884

RESUMEN

Melanization and Toll pathway activation are essential innate immune mechanisms in insects, which result in the generation of reactive compounds and antimicrobial peptides, respectively, to kill pathogens. These two processes are mediated by phenoloxidase (PO) and Spätzle (Spz) through an extracellular network of serine proteases. While some proteases have been identified in Drosophila melanogaster in genetic studies, the exact order of proteolytic activation events remains controversial. Here, we reconstituted the serine protease framework in Drosophila by biochemical methods. This system comprises 10 proteases, i.e., ModSP, cSP48, Grass, Psh, Hayan-PA, Hayan-PB, Sp7, MP1, SPE and Ser7, which form cascade pathways that recognize microbial molecular patterns and virulence factors, and generate PO1, PO2, and Spz from their precursors. Furthermore, the serpin Necrotic negatively regulates the immune response progression by inhibiting ModSP and Grass. The biochemical approach, when combined with genetic analysis, is crucial for addressing problems that long stand in this important research field.


Asunto(s)
Proteínas de Drosophila , Drosophila , Animales , Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Serina Endopeptidasas/genética , Serina Endopeptidasas/metabolismo , Serina Proteasas/genética , Serina Proteasas/metabolismo
18.
Insect Sci ; 30(2): 338-350, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36043911

RESUMEN

Serine esterases (SEs) are hydrolases that catalyze the conversion of carboxylic esters into acids and alcohols. Lipases and carboxylesterases constitute two major groups of SEs. Although over a hundred of insect genomes are known, systematic identification and classification of SEs are rarely performed, likely due to large size and complex composition of the gene family in each species. Considering their key roles in lipid metabolism and other physiological processes, we have categorized 144 M. sexta SEs and SE homologs (SEHs), 114 of which contain a motif of GXSXG. Multiple sequence alignment and phylogenetic tree analysis have revealed 39 neutral lipases (NLs), 3 neutral lipase homologs (NLHs), 11 acidic lipases (ALs), 3 acidic lipase homologs (ALHs), a lipase-3, a triglyceride lipase, a monoglyceride lipase, a hormone-sensitive lipase, and a GDSL lipase. Eighty-three carboxylesterase genes encode 29 α-esterases (AEs), 12 AEHs (e.g., SEH4-1-3), 20 feruloyl esterases (FEs), 2 FEHs, 2 ß-esterases (BEs), 2 integument esterases (IEs), 1 IEH, 4 juvenile hormone esterases, 2 acetylcholinesterases, gliotactin, 6 neuroligins, neurotactin, and an uncharacteristic esterase homolog. In addition to these GXSXG proteins, we have identified 26 phospholipases and 13 thioesterases. Expression profiling of these genes in specific tissues and stages has provided insights into their functions including digestion, detoxification, hormone processing, neurotransmission, reproduction, and developmental regulation. In summary, we have established a framework of information on SEs and related proteins in M. sexta to stimulate their research in the model species and comparative investigations in agricultural pests or disease vectors.


Asunto(s)
Manduca , Animales , Manduca/genética , Manduca/metabolismo , Filogenia , Esterasas/genética , Esterasas/metabolismo , Lipasa/genética , Lipasa/metabolismo , Hidrolasas de Éster Carboxílico/genética , Hidrolasas de Éster Carboxílico/metabolismo
19.
Insect Biochem Mol Biol ; 152: 103895, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36538995

RESUMEN

Endoparasitoid wasps inject venom proteins into the hemocoel of host insects to ensure survival, growth, and development of their progenies by blocking host immunity. We previously identified ten serine protease inhibitors of the serpin superfamily in venom of the endoparasitoid wasp, Microplitis mediator, but it is unclear how these inhibitors may interact with host immune serine proteases. In this study, we investigated the functions of two serpins, MmvSPN-1 and MmvSPN-2, in the regulation of humoral immune responses in two hosts, the oriental armyworm Pseudaletia separate and the cotton bollworm Helicoverpa armigera, by dsRNA knockdown and biochemical assays using recombinant proteins. Knockdown of the two serpins resulted in increases in prophenoloxidase (PPO) activation and antimicrobial peptide (AMP) production in the hosts. After injection into the host hemocoel, the recombinant serpins inhibited PPO activation and AMP transcription. Mass spectrometry analysis of the pull-downs and in vitro reconstitution experiments revealed that HacSP29, a clip-domain serine protease in H. armigera, is the target of these two serpins. Therefore, these two inhibitors in the wasp venom may protect eggs from attacks by melanization and AMPs in the host insects.


Asunto(s)
Mariposas Nocturnas , Serpinas , Avispas , Animales , Avispas/metabolismo , Serpinas/genética , Serpinas/metabolismo , Serina Endopeptidasas , Mariposas Nocturnas/genética , Mariposas Nocturnas/metabolismo , Venenos de Avispas/metabolismo , Serina Proteasas/genética , Serina Proteasas/metabolismo , Péptidos Antimicrobianos , Proteínas de Insectos/metabolismo
20.
Artículo en Inglés | MEDLINE | ID: mdl-37956012

RESUMEN

Learning robust feature matching between the template and search area is crucial for 3-D Siamese tracking. The core of Siamese feature matching is how to assign high feature similarity to the corresponding points between the template and the search area for precise object localization. In this article, we propose a novel point cloud registration-driven Siamese tracking framework, with the intuition that spatially aligned corresponding points (via 3-D registration) tend to achieve consistent feature representations. Specifically, our method consists of two modules, including a tracking-specific nonlocal registration (TSNR) module and a registration-aided Sinkhorn template-feature aggregation module. The registration module targets the precise spatial alignment between the template and the search area. The tracking-specific spatial distance constraint is proposed to refine the cross-attention weights in the nonlocal module for discriminative feature learning. Then, we use the weighted singular value decomposition (SVD) to compute the rigid transformation between the template and the search area and align them to achieve the desired spatially aligned corresponding points. For the feature aggregation model, we formulate the feature matching between the transformed template and the search area as an optimal transport problem and utilize the Sinkhorn optimization to search for the outlier-robust matching solution. Also, a registration-aided spatial distance map is built to improve the matching robustness in indistinguishable regions (e.g., smooth surfaces). Finally, guided by the obtained feature matching map, we aggregate the target information from the template into the search area to construct the target-specific feature, which is then fed into a CenterPoint-like detection head for object localization. Extensive experiments on KITTI, NuScenes, and Waymo datasets verify the effectiveness of our proposed method.

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