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  1 / 1779 MEDLINE  
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[PMID]:28747471
[Au] Autor:Chapman PD; Bradley SP; Haught EJ; Riggs KE; Haffar MM; Daly KC; Dacks AM
[Ad] Endereço:Department of Biology, West Virginia University, Morgantown, WV 26506, USA.
[Ti] Título:Co-option of a motor-to-sensory histaminergic circuit correlates with insect flight biomechanics.
[So] Source:Proc Biol Sci;284(1859), 2017 Jul 26.
[Is] ISSN:1471-2954
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Nervous systems must adapt to shifts in behavioural ecology. One form of adaptation is neural exaptation, in which neural circuits are co-opted to perform additional novel functions. Here, we describe the co-option of a motor-to-somatosensory circuit into an olfactory network. Many moths beat their wings during odour-tracking, whether walking or flying, causing strong oscillations of airflow around the antennae, altering odour plume structure. This self-induced sensory stimulation could impose selective pressures that influence neural circuit evolution, specifically fostering the emergence of corollary discharge circuits. In , a pair of mesothoracic to deutocerebral histaminergic neurons (MDHns), project from the mesothoracic neuromere to both antennal lobes (ALs), the first olfactory neuropil. Consistent with a hypothetical role in providing the olfactory system with a corollary discharge, we demonstrate that the MDHns innervate the ALs of advanced and basal moths, but not butterflies, which differ in wing beat and flight pattern. The MDHns probably arose in crustaceans and in many arthropods innervate mechanosensory areas, but not the olfactory system. The MDHns, therefore, represent an example of architectural exaptation, in which neurons that provide motor output information to mechanosensory regions have been co-opted to provide information to the olfactory system in moths.
[Mh] Termos MeSH primário: Voo Animal
Manduca/fisiologia
Neurônios/fisiologia
Bulbo Olfatório/fisiologia
[Mh] Termos MeSH secundário: Animais
Histamina
Olfato/fisiologia
Asas de Animais
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
820484N8I3 (Histamine)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180202
[Lr] Data última revisão:
180202
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170728
[St] Status:MEDLINE


  2 / 1779 MEDLINE  
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[PMID]:28953952
[Au] Autor:Yuan C; Xing L; Wang M; Wang X; Yin M; Wang Q; Hu Z; Zou Z
[Ad] Endereço:State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
[Ti] Título:Inhibition of melanization by serpin-5 and serpin-9 promotes baculovirus infection in cotton bollworm Helicoverpa armigera.
[So] Source:PLoS Pathog;13(9):e1006645, 2017 Sep.
[Is] ISSN:1553-7374
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Melanization, an important insect defense mechanism, is mediated by clip-domain serine protease (cSP) cascades and is regulated by serpins. Here we show that proteolytic activation of prophenoloxidase (PPO) and PO-catalyzed melanization kill the baculovirus in vitro. Our quantitative proteomics and biochemical experiments revealed that baculovirus infection of the cotton bollworm, Helicoverpa armigera, reduced levels of most cascade members in the host hemolymph and PO activity. By contrast, serpin-9 and serpin-5 were sequentially upregulated after the viral infection. The H. armigera serpin-5 and serpin-9 regulate melanization by directly inhibiting their target proteases cSP4 and cSP6, respectively and cSP6 activates PPO purified from hemolymph. Furthermore, serpin-5/9-depleted insects exhibited high PO activities and showed resistance to baculovirus infection. Together, our results characterize a part of the melanization cascade in H. armigera, and suggest that natural insect virus baculovirus has evolved a distinct strategy to suppress the host immune system.
[Mh] Termos MeSH primário: Baculoviridae
Hemolinfa/metabolismo
Proteínas de Insetos/metabolismo
Manduca/metabolismo
Serpinas/metabolismo
[Mh] Termos MeSH secundário: Sequência de Aminoácidos/genética
Animais
Peptídeo Hidrolases/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Insect Proteins); 0 (Serpins); EC 3.4.- (Peptide Hydrolases)
[Em] Mês de entrada:1711
[Cu] Atualização por classe:171107
[Lr] Data última revisão:
171107
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170928
[St] Status:MEDLINE
[do] DOI:10.1371/journal.ppat.1006645


  3 / 1779 MEDLINE  
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[PMID]:28600687
[Au] Autor:Rowen E; Gutensohn M; Dudareva N; Kaplan I
[Ad] Endereço:Department of Entomology, Pennsylvania State University, University Park, PA, 16802, USA. epr5119@psu.edu.
[Ti] Título:Carnivore Attractant or Plant Elicitor? Multifunctional Roles of Methyl Salicylate Lures in Tomato Defense.
[So] Source:J Chem Ecol;43(6):573-585, 2017 Jun.
[Is] ISSN:1573-1561
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Synthetic plant volatile lures attract natural enemies, but may have non-target effects due to the multifunctional nature of volatile signals. For example, methyl salicylate (MeSA) is used to attract predators, yet also serves as a signaling hormone involved in plant pathogen defense. We investigated the consequences of deploying MeSA lures to attract predators for tomato (Solanum lycopersicum) defense against herbivores. To understand the spatial distribution of the lure's effect, we exposed tomatoes in the field to MeSA along a linear distance gradient and induced defenses by simulating feeding by hornworm caterpillars in a fully crossed factorial design (+/- MeSA, +/- herbivory). Subsequently, we analyzed activity of several defensive proteins (protease inhibitors, polyphenol oxidase, peroxidase), development of hornworm larvae (Manduca sexta), growth of fungal pathogens (Cladosporium and Alternaria), and attractiveness to herbivores and predators. Overall, MeSA-exposed plants were more resistant to both insects and pathogens. Secondary pathogen infection was reduced by 25% in MeSA exposed plants, possibly due to elevated polyphenol oxidase activity. Interestingly, we found that lures affected plant pathogen defenses equivalently across all distances (up to 4 m away) indicating that horizontal diffusion of a synthetic volatile may be greater than previously assumed. While thrips avoided colonizing hornworm- damaged tomato plants, this induced resistance was not observed upon pre-exposure to MeSA, suggesting that MeSA suppresses the repellant effect induced by herbivory. Thus, using MeSA lures in biological control may inadvertently protect crops from pathogens, but has mixed effects on plant resistance to insect herbivores.
[Mh] Termos MeSH primário: Herbivoria
Lycopersicon esculentum
Manduca/fisiologia
Salicilatos/química
Salicilatos/farmacologia
[Mh] Termos MeSH secundário: Alternaria/crescimento & desenvolvimento
Animais
Catecol Oxidase/metabolismo
Cladosporium/crescimento & desenvolvimento
Larva/fisiologia
Lycopersicon esculentum/metabolismo
Lycopersicon esculentum/microbiologia
Peroxidase/metabolismo
Controle Biológico de Vetores
Folhas de Planta/microbiologia
Inibidores de Proteases/metabolismo
Espectrometria de Massas em Tandem
Compostos Orgânicos Voláteis/química
Compostos Orgânicos Voláteis/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Protease Inhibitors); 0 (Salicylates); 0 (Volatile Organic Compounds); EC 1.10.3.1 (Catechol Oxidase); EC 1.11.1.7 (Peroxidase); LAV5U5022Y (methyl salicylate)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170801
[Lr] Data última revisão:
170801
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170611
[St] Status:MEDLINE
[do] DOI:10.1007/s10886-017-0856-6


  4 / 1779 MEDLINE  
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[PMID]:28366787
[Au] Autor:He Y; Wang Y; Yang F; Jiang H
[Ad] Endereço:Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA.
[Ti] Título:Manduca sexta hemolymph protease-1, activated by an unconventional non-proteolytic mechanism, mediates immune responses.
[So] Source:Insect Biochem Mol Biol;84:23-31, 2017 May.
[Is] ISSN:1879-0240
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Tissue damage or pathogen invasion triggers the auto-proteolysis of an initiating serine protease (SP), rapidly leading to sequential cleavage activation of other cascade members to set off innate immune responses in insects. Recently, we presented evidence that Manduca sexta hemolymph protease-1 zymogen (proHP1) is a member of the SP system in this species, and may activate proHP6. HP6 stimulates melanization and induces antimicrobial peptide synthesis. Here we report that proHP1 adopts an active conformation (*) to carry out its function, without a requirement for proteolytic activation. Affinity chromatography using HP1 antibodies isolated from induced hemolymph the 48 kDa proHP1 and also a 90 kDa band (detected by SDS-PAGE under reducing conditions) containing proHP1 and several serpins, as revealed by mass spectrometric analysis. Identification of tryptic peptides from these 90 kDa complexes included peptides from the amino-terminal regulatory part of proHP1, indicating that proHP1* was not cleaved, and that it had formed a complex with the serpins. As suicide inhibitors, serpins form SDS-stable, acyl-complexes when they are attacked by active proteases, indicating that proHP1* was catalytically active. Detection of M. sexta serpin-1, 4, 9, 13 and smaller amounts of serpin-3, 5, 6 in the complexes suggests that it is regulated by multiple serpins in hemolymph. We produced site-directed mutants of proHP1b for cleavage by bovine blood coagulation factor Xa at the designed proteolytic activation site, to generate a form of proHP1b that could be activated by Factor Xa. However, proHP1b cut by Factor Xa failed to activate proHP6 and, via HP6, proHP8 or proPAP1. This negative result is consistent with the suggestion that proHP1* is a physiological mediator of immune responses. Further research is needed to investigate the conformational change that results in conversion of proHP1 to active proHP1*.
[Mh] Termos MeSH primário: Manduca/imunologia
Serina Proteases/metabolismo
[Mh] Termos MeSH secundário: Sequência de Aminoácidos
Animais
Hemolinfa/enzimologia
Proteínas de Insetos/metabolismo
Larva/enzimologia
Manduca/enzimologia
Dados de Sequência Molecular
Serina Proteases/isolamento & purificação
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Insect Proteins); EC 3.4.- (Serine Proteases)
[Em] Mês de entrada:1709
[Cu] Atualização por classe:170906
[Lr] Data última revisão:
170906
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170404
[St] Status:MEDLINE


  5 / 1779 MEDLINE  
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[PMID]:28277956
[Au] Autor:Martinez E; Menze MA; Agosta SJ
[Ti] Título:Reduced Mitochondrial Efficiency Explains Mismatched Growth and Metabolic Rate at Supraoptimal Temperatures.
[So] Source:Physiol Biochem Zool;90(2):294-298, 2017 Mar/Apr.
[Is] ISSN:1537-5293
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The relationship between whole-organism growth and metabolism is generally assumed to be positive and causative; higher metabolic rates support higher growth rates. In Manduca sexta, existing data demonstrate a deviation from this simple prediction: at supraoptimal temperatures for larval growth, metabolic rate keeps increasing while growth rate is decreasing. This mismatch presumably reflects the rising "cost of maintenance" with temperature. Precisely what constitutes this cost is not clear, but we suspect the efficiency with which mitochondria harness oxygen and organic substrates into cellular energy (ATP) is key. We tested this by integrating existing data on M. sexta growth and metabolism with new data on mitochondrial bioenergetics across the temperature range 14°-42°C. Across this range, our measure of mitochondrial efficiency closely paralleled larval growth rates. At supraoptimal temperatures for growth, mitochondrial efficiency was reduced, which could explain the mismatch between growth and metabolism observed at the whole-organism level.
[Mh] Termos MeSH primário: Metabolismo Energético/fisiologia
Manduca/crescimento & desenvolvimento
Manduca/metabolismo
Mitocôndrias/fisiologia
Temperatura Ambiente
[Mh] Termos MeSH secundário: Animais
Larva/crescimento & desenvolvimento
Larva/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1707
[Cu] Atualização por classe:170727
[Lr] Data última revisão:
170727
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170310
[St] Status:MEDLINE
[do] DOI:10.1086/689871


  6 / 1779 MEDLINE  
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[PMID]:28188725
[Au] Autor:Andersen MK; Jensen SO; Overgaard J
[Ad] Endereço:Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark. Electronic address: mads.andersen@bios.au.dk.
[Ti] Título:Physiological correlates of chill susceptibility in Lepidoptera.
[So] Source:J Insect Physiol;98:317-326, 2017 Apr.
[Is] ISSN:1879-1611
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The majority of insects enter a state of reversible coma if temperature is lowered sufficiently. If the cold treatment is not too severe these insects recover gradually when returned to benign temperatures in a time-dependent manner that often depends on the duration and intensity of the cold exposure. Previous studies have associated these phenotypes to changes in membrane potential (V ) and ion balance, and especially hemolymph [K ] is known to be of importance for the recovery time. In the present study we examined this link in three species of Lepidoptera as insects from this order are known to possess resting hemolymph [K ] that would severely compromise V in other insects. Specifically, we exposed larval and adult Manduca sexta, larval Bombyx mori, and adult Heliconius cydno to stressful cold (0°C) for extended periods of time. Subsequently we measured chill coma recovery time (CCRT), ion- and water balance, and muscle V . As expected we find that resting hemolymph [K ] is high and that resting hemolymph [Na ] is low compared to most other insect species. Muscle V depolarised considerably during acute cold exposure, but did so in a manner that was not associated with changes in ion balance. However, prolonged cold exposure coincided with an increase of hemolymph [K ] and further depolarisation of V which correlated well with prolongation of CCRT. Combined this demonstrates how insects with different ionic compositions generally suffer from similar consequences of cold stress as other species, such that cold tolerance of chill-susceptible insects within Lepidoptera is also intimately linked to maintenance of ion balance and membrane polarisation.
[Mh] Termos MeSH primário: Aclimatação
Bombyx/fisiologia
Borboletas/fisiologia
Manduca/fisiologia
[Mh] Termos MeSH secundário: Animais
Temperatura Baixa/efeitos adversos
Feminino
Larva/crescimento & desenvolvimento
Larva/fisiologia
Masculino
Potenciais da Membrana
Músculos/fisiologia
Especificidade da Espécie
Equilíbrio Hidroeletrolítico
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1707
[Cu] Atualização por classe:170714
[Lr] Data última revisão:
170714
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170212
[St] Status:MEDLINE


  7 / 1779 MEDLINE  
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[PMID]:28153982
[Au] Autor:Broadhead GT; Basu T; von Arx M; Raguso RA
[Ad] Endereço:Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14850, USA gtb49@cornell.edu.
[Ti] Título:Diel rhythms and sex differences in the locomotor activity of hawkmoths.
[So] Source:J Exp Biol;220(Pt 8):1472-1480, 2017 Apr 15.
[Is] ISSN:1477-9145
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Circadian patterns of activity are considered ubiquitous and adaptive, and are often invoked as a mechanism for temporal niche partitioning. Yet, comparisons of rhythmic behavior in related animal species are uncommon. This is particularly true of Lepidoptera (butterflies and moths), in which studies of whole-animal patterns of behavior are far outweighed by examinations of tissue-specific molecular clocks. Here, we used a comparative approach to examine the circadian patterns of flight behavior in and [two distantly related species of hawkmoth (Sphingidae)]. By filming isolated, individual animals, we were able to examine rhythmic locomotor (flight) activity at the species level, as well as at the level of the individual sexes, and in the absence of interference from social interaction. Our results confirmed classic descriptions of strictly nocturnal behavior in and demonstrated a dramatically different activity pattern in Furthermore, we showed distinct species and sex-specific differences in the maintenance of the endogenous rhythm under conditions of constant darkness. In both species, female activity peaked in advance of males whereas male activity coincided with periods of female sexual receptivity. This suggests a role for circadian patterns of locomotor activity in synchronizing periods of sexual receptivity between the sexes.
[Mh] Termos MeSH primário: Ritmo Circadiano
Voo Animal
Manduca/fisiologia
Mariposas/fisiologia
[Mh] Termos MeSH secundário: Animais
Escuridão
Feminino
Masculino
Caracteres Sexuais
Comportamento Sexual Animal
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1706
[Cu] Atualização por classe:170616
[Lr] Data última revisão:
170616
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170204
[St] Status:MEDLINE
[do] DOI:10.1242/jeb.143966


  8 / 1779 MEDLINE  
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[PMID]:28011823
[Au] Autor:Adamo SA; Easy RH; Kovalko I; MacDonald J; McKeen A; Swanburg T; Turnbull KF; Reeve C
[Ad] Endereço:Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada B3H 4R2 sadamo@dal.ca.
[Ti] Título:Predator exposure-induced immunosuppression: trade-off, immune redistribution or immune reconfiguration?
[So] Source:J Exp Biol;220(Pt 5):868-875, 2017 Mar 01.
[Is] ISSN:1477-9145
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Although predator exposure increases the risk of wound infections, it typically induces immunosuppression. A number of non-mutually exclusive hypotheses have been put forward to explain this immunosuppression, including: trade-offs between the immune system and other systems required for anti-predator behaviour, redistribution of immune resources towards mechanisms needed to defend against wound infections, and reconfiguration of the immune system to optimize defence under the physiological state of fight-or-flight readiness. We tested the ability of each hypothesis to explain the effects of chronic predator stress on the immune system of the caterpillar Predator exposure induced defensive behaviours, reduced mass gain, increased development time and increased the concentration of the stress neurohormone octopamine. It had no significant effect on haemocyte number, melanization rate, phenoloxidase activity, lysozyme-like activity or nodule production. Predator stress reduced haemolymph glutathione concentrations. It also increased constitutive expression of the antimicrobial peptide but reduced expression in response to an immune challenge. These results best fit the immune reconfiguration hypothesis, although the other hypotheses are also consistent with some results. Interpreting stress-related changes in immune function may require an examination at the level of the whole organism.
[Mh] Termos MeSH primário: Manduca/fisiologia
Comportamento Predatório
Estresse Fisiológico
[Mh] Termos MeSH secundário: Animais
Reação de Fuga
Regulação da Expressão Gênica
Glutationa/análise
Glutationa/imunologia
Hemócitos/citologia
Hemócitos/imunologia
Hemolinfa/imunologia
Tolerância Imunológica
Proteínas de Insetos/análise
Proteínas de Insetos/imunologia
Manduca/citologia
Manduca/genética
Manduca/imunologia
Octopamina/análise
Octopamina/imunologia
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Insect Proteins); 0 (attacin antibacterial protein, insect); 14O50WS8JD (Octopamine); GAN16C9B8O (Glutathione)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170829
[Lr] Data última revisão:
170829
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161225
[St] Status:MEDLINE
[do] DOI:10.1242/jeb.153320


  9 / 1779 MEDLINE  
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[PMID]:27989837
[Au] Autor:Wang Y; Jiang H
[Ad] Endereço:Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, United States.
[Ti] Título:Prophenoloxidase activation and antimicrobial peptide expression induced by the recombinant microbe binding protein of Manduca sexta.
[So] Source:Insect Biochem Mol Biol;83:35-43, 2017 Apr.
[Is] ISSN:1879-0240
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Manduca sexta microbe binding protein (MBP) is a member of the ß-1,3-glucanase-related protein superfamily that includes Gram-negative bacteria-binding proteins (GNBPs), ß-1,3-glucan recognition proteins (ßGRPs), and ß-1,3-glucanases. Our previous and current studies showed that the purified MBP from baculovirus-infected insect cells had stimulated prophenoloxidase (proPO) activation in the hemolymph of naïve and immune challenged larvae and that supplementation of the exogenous MBP and peptidoglycans (PGs) had caused synergistic increases in PO activity. To explore the underlying mechanism, we separated by SDS-PAGE naïve and induced larval plasma treated with buffer or MBP and detected on immunoblots changes in intensity and/or mobility of hemolymph (serine) proteases [HP14, HP21, HP6, HP8, proPO-activating proteases (PAPs) 1-3] and their homologs (SPH1, SPH2). In a nickel pull-down assay, we observed association of MBP with proHP14 (slightly), ßGRP2, PG recognition protein-1 (PGRP1, indirectly), SPH1, SPH2, and proPO2. Further experiments indicated that diaminopimelic acid (DAP) or Lys PG, MBP, PGRP1, and proHP14 together trigger the proPO activation system in a Ca -dependent manner. Injection of the recombinant MBP into the 5th instar naïve larvae significantly induced the expression of several antimicrobial peptide genes, revealing a possible link between HP14 and immune signal transduction. Together, these results suggest that the recognition of Gram-negative or -positive bacteria via their PGs induces the melanization and Toll pathways in M. sexta.
[Mh] Termos MeSH primário: Monofosfato de Adenosina/metabolismo
Proteínas de Insetos/fisiologia
Manduca/imunologia
[Mh] Termos MeSH secundário: Animais
Catecol Oxidase/metabolismo
Precursores Enzimáticos/metabolismo
Hemolinfa/metabolismo
Manduca/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Enzyme Precursors); 0 (Insect Proteins); 415SHH325A (Adenosine Monophosphate); EC 1.10.3.- (pro-phenoloxidase); EC 1.10.3.1 (Catechol Oxidase)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170822
[Lr] Data última revisão:
170822
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161220
[St] Status:MEDLINE


  10 / 1779 MEDLINE  
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[PMID]:27986638
[Au] Autor:Brummett LM; Kanost MR; Gorman MJ
[Ad] Endereço:Department of Biochemistry and Molecular Biophysics, 141 Chalmers, 1711 Claflin Road, Kansas State University, Manhattan, KS 66506, USA. Electronic address: lmbrumme@ksu.edu.
[Ti] Título:The immune properties of Manduca sexta transferrin.
[So] Source:Insect Biochem Mol Biol;81:1-9, 2017 Feb.
[Is] ISSN:1879-0240
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Transferrins are secreted proteins that bind iron. The well-studied transferrins are mammalian serum transferrin, which is involved in iron transport, and mammalian lactoferrin, which functions as an immune protein. Lactoferrin and lactoferrin-derived peptides have bactericidal activity, and the iron-free form of lactoferrin has bacteriostatic activity due to its ability to sequester iron. Insect transferrin is similar in sequence to both serum transferrin and lactoferrin, and its functions are not well-characterized; however, many studies of insect transferrin indicate that it has some type of immune function. The goal of this study was to determine the specific immune functions of transferrin from Manduca sexta (tobacco hornworm). We verified that transferrin expression is upregulated in response to infection in M. sexta larvae and determined that the concentration of transferrin in hemolymph increases from 2 µM to 10 µM following an immune challenge. It is also present in molting fluid and prepupal midgut fluid, two extracellular fluids with immune capabilities. No immune-induced proteolytic cleavage of transferrin in hemolymph was observed; therefore, M. sexta transferrin does not appear to be a source of antimicrobial peptides. Unlike iron-saturated lactoferrin, iron-saturated transferrin had no detectable antibacterial activity. In contrast, 1 µM iron-free transferrin inhibited bacterial growth, and this inhibition was blocked by supplementing the culture medium with 1 µM iron. Our results suggest that M. sexta transferrin does not have bactericidal activity, but that it does have a bacteriostatic function that depends on its iron sequestering ability. This study supports the hypothesis that insect transferrin participates in an iron withholding strategy to protect insects from infectious bacteria.
[Mh] Termos MeSH primário: Manduca/imunologia
Transferrina/fisiologia
[Mh] Termos MeSH secundário: Animais
Líquido Extracelular/metabolismo
Ferro/metabolismo
Testes de Sensibilidade Microbiana
Transferrina/química
Transferrina/isolamento & purificação
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Transferrin); E1UOL152H7 (Iron)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170828
[Lr] Data última revisão:
170828
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161218
[St] Status:MEDLINE



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