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1.
Chemosphere ; 262: 128290, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182139

RESUMO

Tumble dryer lint has been employed as a surrogate for synthetic and processed (microplastic) fibres discharged to the environment from laundering activities and exposed to marine mussels (Mytilus galloprovinciallis) in controlled experiments for a period of 7 d. A range of biological responses at different levels of organisation were subsequently determined, with copper employed concurrently as a positive control. Physiological changes were assessed from measurements of clearance rate, histopathological effects were evaluated from abnormalities in (or injuries to) gill and digestive gland tissues, and genetic damage was determined by measuring DNA strand breaks using the comet assay. With increasing lint concentration (over the range 56-180 mg L-1) we observed a reduction in mean clearance rate, increasing extents of abnormality in both gills (e.g. deciliation and hypertrophy) and digestive gland (e.g. atrophy and necrosis), and an increase in damage to DNA. The precise causes of these effects are unclear but likely arise from both the fibrous material itself and from chemicals (e.g. additives and metals) that are mobilised from the polymers into seawater or the digestive tract. The latter assertion is consistent with an observed increase in the release of certain trace elements (e.g. zinc) into the exposure medium with increasing lint concentration. Although microfibre concentrations we employed are significantly greater than those typically encountered in the environment, the results indicate the potential for this type of material to exert a range of adverse effects on exposed marine animals.


Assuntos
Dano ao DNA , Microplásticos/toxicidade , Mytilus/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Ensaio Cometa , Cobre/toxicidade , Brânquias/efeitos dos fármacos , Brânquias/metabolismo , Hemolinfa/efeitos dos fármacos , Hemolinfa/metabolismo , Taxa de Depuração Metabólica , Modelos Teóricos , Mytilus/genética , Mytilus/metabolismo , Água do Mar/química
2.
Arch Insect Biochem Physiol ; 105(3): e21741, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33002240

RESUMO

Apoptosis is a process of programmed cell death that is regulated by genes independently. The Bm30kc6 gene is a kind of small molecular lipoprotein about 30 kDa, expressed highly in the late stage of the silkworm hemolymph. Our study showed that overexpression of Bm30kc6 could decrease caspase-3 activation. Meanwhile, activation of caspase-3 increased when Bm30kc6 expression was disturbed by small interfering RNA (siRNA). Cell apoptosis was decreased when Bm30kc6 was overexpressed under UV treatment. The apoptosis rate induced by actinomycin D is similar to the trend by UV. It was inferred that Bm30kc6 has an inhibitory effect on the apoptosis of silkworm cells. The apoptosis-related genes, such as BmFadd, BmDredd, and BmDaxx were increased after overexpression of Bm30kc6 or decreased after interference of siRNA. It was speculated that there was an interactive relationship between Bm30kc6, BmDaxx, BmFadd, and BmDredd in the apoptosis signaling pathways. We investigated the transcription expression of the Bm30kc6 gene in different growth stages and tissues of the silkworm. The results showed that Bm30kc6 reached its peak in the hemolymph during the 6th to 7th days of the 5th instar, or in spinning post 24 h of the silk gland. In the silkworm BmN cells treated with caspase-3/7 inhibitor, the caspase-3 enzyme activity, and the expression levels of Bm30kc6, BmFadd, BmDredd, and BmDaxx were significantly reduced. The expression levels of Bm30kc6 increased sharply when silkworms were treated by molting hormone at Day 3 or 5 of the 5th instar. The results indicated that the expression of the Bm30kc6 gene was affected by the molting hormone and was likely to be its downstream target. In conclusion, the results suggest that the Bm30kc6 gene is involved in the regulation of the apoptotic signaling pathway and plays a role in the apoptotic process.


Assuntos
Apoptose/genética , Bombyx/crescimento & desenvolvimento , Bombyx/genética , Animais , Bombyx/metabolismo , Caspase 3/genética , Caspase 3/metabolismo , Inibidores de Caspase/farmacologia , Dactinomicina/farmacologia , Ecdisona/farmacologia , Regulação da Expressão Gênica no Desenvolvimento , Hemolinfa/metabolismo , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , RNA Interferente Pequeno , Transdução de Sinais , Raios Ultravioleta
3.
Arch Insect Biochem Physiol ; 105(3): e21743, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32979236

RESUMO

Many freshwater ecosystems worldwide undergo hypoxia events that can trigger physiological, behavioral, and molecular responses in many organisms. Among such molecular responses, the regulation of the hemocyanin (Hc) protein expression which plays a major role in oxygen transportation within aquatic insects remains poorly understood. The stoneflies (Plecoptera) are aquatic insects that possess a functional Hc in the hemolymph similar to crustacean that co-occurs with a nonfunctional Hc protein, hexamerins (Hx). However, the role of both proteins during hypoxia remains undetermined. Here, we evaluated the effect of hypoxia on the expression of Hc and Hx proteins via a comparison between hypoxia and normoxia amino acid sequence variation and protein expression pattern within 23 stonefly species. We induced short-term hypoxia in wild-caught stoneflies species, sequenced the target region of Hc and Hx by complementary DNA synthesis, characterized the protein biochemistry using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, ultrafiltration, and polarographic fluorometric method, and amplified the genome region of the hypoxia-inducible factor (HIF) transcriptional response element that regulated Hc using genome walking library approach. We found a lack of Hc expression in all examined species during hypoxia conditions, despite recognition of the HIF gene region as a possible regulatory factor of Hc, suggesting that compensatory responses as metabolic changes or behavioral tracheal movements to enhance respiratory efficiency could be possible mechanics to compensate for hypoxia. A short Hc-like novel isoform was detected instead in these 23 species, possibly due to either protein degradation or alternative splicing mechanisms, suggesting that the protein could be performing a different function other than oxygen transportation. Hx during hypoxia was expressed and exhibited species-level amino acid changes, highlighting a possible role during hypoxia. Our results demonstrate that hypoxia could enable a similar potential adaptive response of multiple species regarding specific physiological requirements, thereby shedding light on community behavior in stress environments that may help us to improve conservation practices and biomonitoring.


Assuntos
Hemocianinas/metabolismo , Proteínas de Insetos/metabolismo , Neópteros/metabolismo , Sequência de Aminoácidos , Anaerobiose , Animais , Hemocianinas/química , Hemocianinas/genética , Hemolinfa/metabolismo , Proteínas de Insetos/química , Proteínas de Insetos/genética , Neópteros/genética , Neópteros/crescimento & desenvolvimento , Ninfa/metabolismo , Análise de Sequência de DNA
4.
Nat Commun ; 11(1): 4653, 2020 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-32938923

RESUMO

Cancer cells demand excess nutrients to support their proliferation, but how tumours exploit extracellular amino acids during systemic metabolic perturbations remain incompletely understood. Here, we use a Drosophila model of high-sugar diet (HSD)-enhanced tumourigenesis to uncover a systemic host-tumour metabolic circuit that supports tumour growth. We demonstrate coordinate induction of systemic muscle wasting with tumour-autonomous Yorkie-mediated SLC36-family amino acid transporter expression as a proline-scavenging programme to drive tumourigenesis. We identify Indole-3-propionic acid as an optimal amino acid derivative to rationally target the proline-dependency of tumour growth. Insights from this whole-animal Drosophila model provide a powerful approach towards the identification and therapeutic exploitation of the amino acid vulnerabilities of tumourigenesis in the context of a perturbed systemic metabolic network.


Assuntos
Açúcares da Dieta/efeitos adversos , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/fisiopatologia , Neoplasias Experimentais/fisiopatologia , Prolina/metabolismo , Sistemas de Transporte de Aminoácidos/genética , Sistemas de Transporte de Aminoácidos/metabolismo , Animais , Animais Geneticamente Modificados , Carcinogênese , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Fatores de Crescimento de Fibroblastos/genética , Fatores de Crescimento de Fibroblastos/metabolismo , Perfilação da Expressão Gênica , Hemolinfa/efeitos dos fármacos , Hemolinfa/metabolismo , Larva , Debilidade Muscular/induzido quimicamente , Debilidade Muscular/patologia , Atrofia Muscular/induzido quimicamente , Atrofia Muscular/patologia , Neoplasias Experimentais/etiologia , Proteínas Nucleares/genética , Receptores Proteína Tirosina Quinases/metabolismo , Transativadores/genética , Proteínas ras/genética
5.
PLoS Pathog ; 16(9): e1008901, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32997722

RESUMO

The immune system of a host functions critically in shaping the composition of the microbiota, and some microbes are involved in regulating host endocrine system and development. However, whether the immune system acts on endocrine and development by shaping the composition of the microbiota remains unclear, and few molecular players or microbes involved in this process have been identified. In the current study, we found that RNA interference of a C-type lectin (HaCTL3) in the cotton bollworm Helicoverpa armigera suppresses ecdysone and juvenile hormone signaling, thus reducing larval body size and delaying pupation. Depletion of HaCTL3 also results in an increased abundance of Enterocuccus mundtii in the hemolymph, which may escape from the gut. Furthermore, HaCTL3 and its controlled antimicrobial peptides (attacin, lebocin, and gloverin) are involved in the clearance of E. mundtii from the hemolymph via phagocytosis or direct bactericidal activity. Injection of E. mundtii into larval hemocoel mimics HaCTL3-depleted phenotypes and suppresses ecdysone and juvenile hormone signaling. Taken together, we conclude that HaCTL3 maintains normal larval growth and development of H. armigera via suppressing the abundance of E. mundtii in the hemolymph. Our results provide the first evidence of an immune system acting on an endocrine system to modulate development via shaping the composition of microbiota in insect hemolymph. Thus, this study will deepen our understanding of the interaction between immunity and development.


Assuntos
Homeostase/fisiologia , Larva/crescimento & desenvolvimento , Larva/metabolismo , Lectinas Tipo C/metabolismo , Animais , Perfilação da Expressão Gênica/métodos , Hemolinfa/metabolismo , Imunidade Inata/genética , Proteínas de Insetos/metabolismo , Insetos/metabolismo , Fagocitose/fisiologia
6.
PLoS One ; 15(8): e0234892, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32817668

RESUMO

The mosquito Aedes aegypti vectors the arboviral diseases yellow fever, dengue, Zika and chikungunya. Larvae are usually found developing in freshwater; however, more recently they have been increasingly found in brackish water, potential habitats which are traditionally ignored by mosquito control programs. Aedes aegypti larvae are osmo-regulators maintaining their hemolymph osmolarity in a range of ~ 250 to 300 mOsmol l-1. In freshwater, the larvae must excrete excess water while conserving ions while in brackish water, they must alleviate an accumulation of salts. The compensatory physiological mechanisms must involve the transport of ions and water but little is known about the water transport mechanisms in the osmoregulatory organs of these larvae. Water traverses cellular membranes predominantly through transmembrane proteins named aquaporins (AQPs) and Aedes aegypti possesses 6 AQP homologues (AaAQP1 to 6). The objective of this study was to determine if larvae that develop in freshwater or brackish water have differential aquaporin expression in osmoregulatory organs, which could inform us about the relative importance and function of aquaporins to mosquito survival under these different osmotic conditions. We found that AaAQP transcript abundance was similar in organs of freshwater and brackish water mosquito larvae. Furthermore, in the Malpighian tubules and hindgut AaAQP protein abundance was unaffected by the rearing conditions, but in the gastric caeca the protein level of one aquaporin, AaAQP1 was elevated in brackish water. We found that AaAQP1 was expressed apically while AaAQP4 and AaAQP5 were found to be apical and/or basal in the epithelia of osmoregulatory organs. Overall, the results suggest that aquaporin expression in the osmoregulatory organs is mostly consistent between larvae that are developing in freshwater and brackish water. This suggests that aquaporins may not have major roles in adapting to longterm survival in brackish water or that aquaporin function may be regulated by other mechanisms like post-translational modifications.


Assuntos
Aedes/genética , Aquaporinas/genética , Osmorregulação/genética , Aedes/fisiologia , Animais , Aquaporinas/metabolismo , Infecções por Arbovirus , Transporte Biológico , Ecossistema , Água Doce , Expressão Gênica/genética , Regulação da Expressão Gênica/genética , Hemolinfa/metabolismo , Proteínas de Insetos/metabolismo , Larva/genética , Larva/metabolismo , Osmorregulação/fisiologia , Osmose , Águas Salinas , Salinidade , Água/metabolismo
7.
PLoS One ; 15(5): e0232360, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32379772

RESUMO

The free radical nitric oxide (NO) is a powerful metabolic regulator in vertebrates and invertebrates. At cellular concentrations in the nanomolar range, and simultaneously reduced internal oxygen partial pressures (pO2), NO completely inhibits cytochrome-c-oxidase (CytOx) activity and hence mitochondrial- and whole-tissue respiration. The infaunal clam Arctica islandica regulates pO2 of hemolymph and mantle cavity water to mean values of <5 kPa, even in a completely oxygen-saturated environment of 21 kPa. These low internal pO2 values support a longer NO lifespan and NO accumulation in the body fluids and can thus trigger a depression of metabolic rate in the clams. Measurable amounts of NO formation were detected in hemocyte cells (~110 pmol NO 100-1 hemocytes h-1 at 6 kPa), which was not prevented in the presence of the NO synthase inhibitor L-NAME, and in the gill filaments of A. islandica. Adding a NO donor to intact gills and tissue homogenate significantly inhibited gill respiration and CytOx activity below 10 kPa. Meanwhile, the addition of the NO-oxidation product nitrite did not affect metabolic rates. The high nitrite levels found in the hemolymph of experimental mussels under anoxia do not indicate cellular NO production, but could be an indication of nitrate reduction by facultative anaerobic bacteria associated with tissue and/or hemolymph biofilms. Our results suggest that NO plays an important role in the initiation of metabolic depression during self-induced burrowing and shell closure of A. islandica. Furthermore, NO appears to reduce mitochondrial oxygen radical formation during surfacing and cellular reoxygenation after prolonged periods of hypoxia and anoxia.


Assuntos
Bivalves/metabolismo , Hipóxia/metabolismo , Óxido Nítrico/metabolismo , Animais , Antioxidantes/metabolismo , Bivalves/fisiologia , Respiração Celular , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Radicais Livres/metabolismo , Brânquias/metabolismo , Glutationa/metabolismo , Hemócitos/metabolismo , Hemolinfa/metabolismo , Longevidade/fisiologia , Mitocôndrias/metabolismo , Nitritos/metabolismo , Oxigênio/metabolismo , Espécies Reativas de Oxigênio/metabolismo
8.
Aquat Toxicol ; 224: 105497, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32388340

RESUMO

Previous research has identified microplastics as new environmental pollutants that are widely distributed in a variety of environments, including aquaculture environments. However, the potential hazard of microplastics to aquaculture animals, especially toward lipid metabolism involved with the survival and growth of aquatic animal, has not yet been investigated. In the present study, redclaw crayfish (Cherax quadricarinatus) were exposed to different concentrations of 200 nm-sized polystyrene microspheres (0, 0.5, and 5 mg/L) for 21 days, to investigate the effects of microplastics on lipid metabolism. After ingestion, the microplastics were distributed in the intestines and hepatopancreas, and appeared to inhibit the growth of Cherax quadricarinatus. Subsequently, the lipid levels in the hepatopancreas and hemolymph was detected, and found that after 21 days of exposure, the lipid content and free fatty acids in the hepatopancreas and hemolymph decreased significantly, and total cholesterol and triglycerides levels increased significantly in the hemolymph. This might have been caused by insufficient intake of exogenous fat. A significant decrease in lipase activity also supported this view. The activity of lipoprotein lipase related to lipolysis in the hepatopancreas increased significantly, while the activity of fatty acid synthase related to fat synthesis increased, and the activity of acetyl-CoA carboxylase decreased. These results indicated disturbed lipid metabolism in the hepatopancreas. The significant increase of lipid transport-related low-density lipoprotein indicated that the lipolytic capacity was higher than the lipid synthesis capacity. The expression levels of fatty acid metabolism-related genes FAD6 and FABP decreased significantly, indicating that the fatty acid utilization ability of hepatopancreas cells was inhibited, which was consistent with the results of enzyme activities. Thus, microplastics represent a potential hazard to redclaw crayfish, at least on lipid metabolism. This study provided basic data on the ecotoxicological effects of microplastics on crustaceans.


Assuntos
Astacoidea/efeitos dos fármacos , Hepatopâncreas/efeitos dos fármacos , Metabolismo dos Lipídeos/efeitos dos fármacos , Poliestirenos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Aquicultura , Astacoidea/metabolismo , Hemolinfa/efeitos dos fármacos , Hemolinfa/metabolismo , Hepatopâncreas/metabolismo , Microesferas , Poliestirenos/química , Poliestirenos/metabolismo , Poluentes Químicos da Água/química , Poluentes Químicos da Água/metabolismo
9.
Toxicon ; 183: 29-35, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32445842

RESUMO

The ant-like bethylid ectoparasitoid Scleroderma guani (Hymenoptera: Bethylidae) envenomates host to suppress immune response. Yet, the roles of its venom in inhibiting melanization of the host hemolymph have not been fully characterized. Here, we demonstrated that S. guani envenomation induced strong inhibition of melanization of the hemolymph from Tenebrio molitor (Coleoptera: Tenebrionidae), permitting the successful development of parasitoid offspring. To reveal venom component associated with such function, a serine proteinase homolog (SguaSPH) rich in the venom of S. guani was characterized. It was found that one of the catalytic triad residues for serine proteinase is absent in the amino acid sequence of SguaSPH. This venom component was abundantly expressed in venom apparatus and adult stages. By enzymatic assays, SguaSPH displayed low trypsin and no chymotrypsin activity, and was able to inhibit phenoloxidase activity in the hemolymph of Ostrinia furnacalis (Lepidoptera: Crambidae). The findings suggest that SguaSPH is essential for interfering with hemolymph melanization of S. guani envenomated host via phenoloxidase cascade disruption.


Assuntos
Monofenol Mono-Oxigenase/metabolismo , Serina Proteases/metabolismo , Animais , Hemolinfa/metabolismo , Proteínas de Insetos/metabolismo , Larva , Tenebrio/metabolismo
10.
Bull Environ Contam Toxicol ; 104(6): 755-762, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32394051

RESUMO

We examined copper accumulation in the hemolymph, gills and hepatopancreas, and hemolymph osmolality, Na+ and Cl- concentrations, together with gill Na+/K+-ATPase and carbonic anhydrase activities, after dietary copper delivery (0, 100 or 500 Cu µg g-1) for 12 days in a fiddler crab, Minuca rapax. In contaminated crabs, copper concentration decreased in the hemolymph and hepatopancreas, but increased in the gills. Hemolymph osmolality and gill Na+/K+-ATPase activity increased while hemolymph [Na+] and [Cl-] and gill carbonic anhydrase activity decreased. Excretion likely accounts for the decreased hemolymph and hepatopancreas copper titers. Dietary copper clearly affected osmoregulatory ability and hemolymph Na+ and Cl- regulation in M. rapax. Gill copper accumulation decreased carbonic anhydrase activity, suggesting that dietary copper affects acid-base balance. Elevated gill Na+/K+-ATPase activity appears to compensate for the ion-regulatory disturbance. These effects of dietary copper illustrate likely impacts on semi-terrestrial species that feed on metal-contaminated sediments.


Assuntos
Bioacumulação , Braquiúros/efeitos dos fármacos , Cobre/metabolismo , Osmorregulação/efeitos dos fármacos , Poluentes Químicos da Água/metabolismo , Animais , Braquiúros/metabolismo , Cobre/análise , Exposição Dietética , Brânquias/efeitos dos fármacos , Brânquias/metabolismo , Hemolinfa/metabolismo , Hepatopâncreas/metabolismo , Transporte de Íons , Concentração Osmolar , Alimentos Marinhos , ATPase Trocadora de Sódio-Potássio/metabolismo , Poluentes Químicos da Água/análise
11.
Gen Comp Endocrinol ; 293: 113478, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32243957

RESUMO

This study identified an insulin-like peptide (ILP) in Macrobrachium rosenbergii termed Mr-ILP and further investigated its function through glucose injection and RNAi. With the analysis of five other glucose metabolism related genes, this study shed light on the molecular mechanism of carbohydrate metabolism in crustaceans. Mr-ILP shared the typical skeleton with six conserved cysteine and mainly expressed in neuroendocrine system. In M. rosenbergii, the elevated hemolymph glucose concentration after glucose injection returned to basal levels in short time, implying an efficient regulatory system in carbohydrate metabolism. Hyperglycemic related genes answered the elevated hemolymph glucose concentration quickly with significant decreased expression level, while Mr-ILP showed delayed response. Instead, glycolysis increased after glucose injection, which indicated glycolysis might play an important role in lowering the abnormally high glucose level. In vivo silencing of Mr-ILP, by injecting the prawns with double-stranded RNA (dsRNA) for 21 days reduced its expression by approximately 75%. Accordingly, glycogen synthase decreased and the trehalose and glycogen level in the hepatopancreas were significantly reduced, indicating the function of Mr-ILP in oligosaccharide and polysaccharide accumulation. When Mr-ILP was silenced, the expression of hyperglycemic related genes were enhanced, but the hemolymph glucose level was not elevated significantly, which might attribute to the increased glycolysis to keep a balanced glucose level in hemolymph.


Assuntos
Metabolismo dos Carboidratos , Insulina/metabolismo , Palaemonidae/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Metabolismo dos Carboidratos/genética , DNA Complementar/genética , Feminino , Regulação da Expressão Gênica , Glucose/administração & dosagem , Hemolinfa/metabolismo , Insulina/química , Insulina/genética , Masculino , Palaemonidae/genética , Filogenia
12.
Tissue Cell ; 63: 101340, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32223951

RESUMO

Artemia salina is an extremophile species that tolerates a wide range of salinity, especially hypertonic media considered lethal for the majority of other aquatic species. In this study, A. salina cysts were hatched in the laboratory and nauplii were acclimated at three different salinities (60, 139 and 212 ppt). Once in the adult phase, their hemolymph osmolality was measured. The animals were strong hypo-osmoregulators in the entire range of tested salinities, with up to 10 fold lower hemolymph osmolalities than their surrounding environment. Immunostaining of Na+/K+-ATPase was done on sections and on whole body mounts of adults in order to localize the ionocytes in different organs. An intense Na+/K+-ATPase immunostaining throughout the cells was observed in the epithelium of the ten pairs of metepipodites. A positive immunoreactivity for Na+/K+-ATPase was also detected in the maxillary glands, in the epithelium of the efferent tubule and of the excretory canal, as well as in the anterior digestive tract. This study confirms the strong hypo-osmotic capacity of this species and affords an overview of the different organs involved in osmoregulation in A. salina adults.


Assuntos
Artemia/enzimologia , Osmorregulação/genética , ATPase Trocadora de Sódio-Potássio/genética , Animais , Artemia/imunologia , Epitélio/imunologia , Epitélio/metabolismo , Brânquias/imunologia , Brânquias/metabolismo , Hemolinfa/imunologia , Hemolinfa/metabolismo , Osmorregulação/imunologia , Salinidade , ATPase Trocadora de Sódio-Potássio/imunologia , Tunísia
13.
Proc Natl Acad Sci U S A ; 117(13): 7317-7325, 2020 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-32188787

RESUMO

Iron sequestration is a recognized innate immune mechanism against invading pathogens mediated by iron-binding proteins called transferrins. Despite many studies on antimicrobial activity of transferrins in vitro, their specific in vivo functions are poorly understood. Here we use Drosophila melanogaster as an in vivo model to investigate the role of transferrins in host defense. We find that systemic infections with a variety of pathogens trigger a hypoferremic response in flies, namely, iron withdrawal from the hemolymph and accumulation in the fat body. Notably, this hypoferremia to infection requires Drosophila nuclear factor κB (NF-κB) immune pathways, Toll and Imd, revealing that these pathways also mediate nutritional immunity in flies. Next, we show that the iron transporter Tsf1 is induced by infections downstream of the Toll and Imd pathways and is necessary for iron relocation from the hemolymph to the fat body. Consistent with elevated iron levels in the hemolymph, Tsf1 mutants exhibited increased susceptibility to Pseudomonas bacteria and Mucorales fungi, which could be rescued by chemical chelation of iron. Furthermore, using siderophore-deficient Pseudomonas aeruginosa, we discover that the siderophore pyoverdine is necessary for pathogenesis in wild-type flies, but it becomes dispensable in Tsf1 mutants due to excessive iron present in the hemolymph of these flies. As such, our study reveals that, similar to mammals, Drosophila uses iron limitation as an immune defense mechanism mediated by conserved iron-transporting proteins transferrins. Our in vivo work, together with accumulating in vitro studies, supports the immune role of insect transferrins against infections via an iron withholding strategy.


Assuntos
Proteínas de Drosophila/metabolismo , Ferro/metabolismo , Transferrina/metabolismo , Animais , Proteínas de Drosophila/imunologia , Drosophila melanogaster , Hemolinfa/imunologia , Hemolinfa/metabolismo , Imunidade Inata , Ferro/imunologia , NF-kappa B/metabolismo , Pseudomonas aeruginosa/metabolismo , Sideróforos/metabolismo , Transferrina/imunologia
14.
J Insect Sci ; 20(2)2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32186739

RESUMO

Hydrogen sulfide (H2S) is a highly poisonous gas with an unpleasant smell of rotten eggs. Previous studies of H2S have primarily focused on its effects on mammalian nervous and respiratory systems. In this study, silkworm developmental parameters and changes in metabolites in response to H2S exposure were investigated using a hemolymph metabolomic approach, based on liquid chromatography-mass spectrometry (LC-MS). The developmental parameters, body weight, cocoon weight, cocoon shell weight, and cocoon shell ratio, were noticeably increased following H2S exposure, with the greatest effects observed at 7.5-µM H2S. Metabolites upregulated under H2S exposure (7.5 µM) were related to inflammation, and included (6Z, 9Z, 12Z)-octadecatrienoic acid, choline phosphate, and malic acid, while hexadecanoic acid was downregulated. Identified metabolites were involved in biological processes, including pyrimidine, purine, and fatty acid metabolism, which are likely to affect silk gland function. These results demonstrate that H2S is beneficial to silkworm development and alters metabolic pathways related to spinning function and inflammation. The present study provides new information regarding the potential functions of H2S in insects and metabolic pathways related to this phenomenon.


Assuntos
Bombyx/crescimento & desenvolvimento , Sulfeto de Hidrogênio/metabolismo , Animais , Bombyx/efeitos dos fármacos , Bombyx/metabolismo , Cromatografia Líquida , Hemolinfa/metabolismo , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Larva/metabolismo , Espectrometria de Massas , Metabolômica
15.
Subcell Biochem ; 94: 35-62, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32189295

RESUMO

Lipoproteins mediate the transport of apolar lipids in the hydrophilic environment of physiological fluids such as the vertebrate blood and the arthropod hemolymph. In this overview, we will focus on the hemolymph lipoproteins in Crustacea that have received most attention during the last years: the high density lipoprotein/ß-glucan binding proteins (HDL-BGBPs), the vitellogenins (VGs), the clotting proteins (CPs) and the more recently discovered large discoidal lipoproteins (dLPs). VGs are female specific lipoproteins which supply both proteins and lipids as storage material for the oocyte for later use by the developing embryo. Unusual within the invertebrates, the crustacean yolk proteins-formerly designated VGs-are more related to the ApoB type lipoproteins of vertebrates and are now termed apolipocrustaceins. The CPs on the other hand, which are present in both sexes, are related to the (sex specific) VGs of insects and vertebrates. CPs serve in hemostasis and wound closure but also as storage proteins in the oocyte. The HDL-BGBPs are the main lipid transporters, but are also involved in immune defense. Most crustacean lipoproteins belong to the family of the large lipid transfer proteins (LLTPs) such as the intracellular microsomal triglyceride transfer protein, the VGs, CPs and the dLPs. In contrast, the HDL-BGBPs do not belong to the LLTPs and their relationship with other lipoproteins is unknown. However, they originate from a common precursor with the dLPs, whose functions are as yet unknown. The majority of lipoprotein studies have focused on decapod crustaceans, especially shrimps, due to their economic importance. However, we will present evidence that the HDL-BGBPs are restricted to the decapod crustaceans which raises the question as to the main lipid transporting proteins of the other crustacean groups. The diversity of crustaceans lipoproteins thus appears to be more complex than reflected by the present state of knowledge.


Assuntos
Crustáceos , Hemolinfa , Lipoproteínas , Animais , Crustáceos/química , Crustáceos/imunologia , Crustáceos/metabolismo , Hemolinfa/química , Hemolinfa/imunologia , Hemolinfa/metabolismo , Lipoproteínas/biossíntese , Lipoproteínas/química , Lipoproteínas/imunologia , Lipoproteínas/metabolismo
16.
Subcell Biochem ; 94: 81-121, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32189297

RESUMO

The composition of insect hemolymph can change depending on many factors, e.g. access to nutrients, stress conditions, and current needs of the insect. In this chapter, insect immune-related polypeptides, which can be permanently or occasionally present in the hemolymph, are described. Their division into peptides or low-molecular weight proteins is not always determined by the length or secondary structure of a given molecule but also depends on the mode of action in insect immunity and, therefore, it is rather arbitrary. Antimicrobial peptides (AMPs) with their role in immunity, modes of action, and classification are presented in the chapter, followed by a short description of some examples: cecropins, moricins, defensins, proline- and glycine-rich peptides. Further, we will describe selected immune-related proteins that may participate in immune recognition, may possess direct antimicrobial properties, or can be involved in the modulation of insect immunity by both abiotic and biotic factors. We briefly cover Fibrinogen-Related Proteins (FREPs), Down Syndrome Cell Adhesion Molecules (Dscam), Hemolin, Lipophorins, Lysozyme, Insect Metalloproteinase Inhibitor (IMPI), and Heat Shock Proteins. The reader will obtain a partial picture presenting molecules participating in one of the most efficient immune strategies found in the animal world, which allow insects to inhabit all ecological land niches in the world.


Assuntos
Antibacterianos/imunologia , Antibacterianos/metabolismo , Proteínas de Insetos/imunologia , Proteínas de Insetos/metabolismo , Insetos/imunologia , Peptídeos/imunologia , Peptídeos/metabolismo , Animais , Hemolinfa/imunologia , Hemolinfa/metabolismo , Insetos/microbiologia
17.
Subcell Biochem ; 94: 233-250, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32189302

RESUMO

The copper-containing hemocyanins are proteins responsible for the binding, transportation and storage of dioxygen within the blood (hemolymph) of many invertebrates. Several additional functions have been attributed to both arthropod and molluscan hemocyanins, including (but not limited to) enzymatic activity (namely phenoloxidase), hormone transport, homeostasis (ecdysis) and hemostasis (clot formation). An important secondary function of hemocyanin involves aspects of innate immunity-such as acting as a precursor of broad-spectrum antimicrobial peptides and microbial/viral agglutination. In this chapter, we present the reader with an up-to-date synthesis of the known functions of hemocyanins and the structural features that facilitate such activities.


Assuntos
Artrópodes , Hemocianinas , Animais , Artrópodes/enzimologia , Artrópodes/imunologia , Artrópodes/metabolismo , Hemocianinas/imunologia , Hemocianinas/metabolismo , Hemolinfa/metabolismo , Imunidade Inata , Monofenol Mono-Oxigenase/metabolismo
18.
Ecotoxicol Environ Saf ; 194: 110380, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32145528

RESUMO

Transgenic crops express Cry proteins exhibit high resistant to target insect pests. When we evaluate the effects of Cry proteins on the parasitoid of target insect pest via tritrophic experiments (transgenic plant-target insect pest-parasitoid) host quality of parasitoids might decrease because of insecticidal protein ingestion, this would cause host-quality mediated effects and influence the accuracy of biosafety assessment. In the current study, high dose of Cry2Aa protein was injected into the hemolymph of Plodia interpunctella by microinjection, and the hemolymph was used as the carrier to deliver Cry protein to Habrobracon hebetor, which has been previously reported as an ectoparasitoid of P. interpunctella larval, in order to avoid the "host-quality mediated effects". Results showed that injected Cry2Aa remained at high concentration and bioactive in the hemolymph of P. interpunctella parasitized by H. hebetor, the hemolymph of P. interpunctella could be used as carriers of Cry protein to H. hebetor, and high dose of Cry2Aa have no negative impacts on the development time, weight of pupa, sex ratio, adults weight (male and female), adult longevity and fecundity, and the activity of stress-related enzymes of H. hebetor. However, the hemolymph of P. interpunctella injected into Galanthus nivalis agglutinin (the positive control) showed significant negative impact on these parameters measured in the present study of H. hebetor. This indicated that Cry2Aa protein had no detrimental effects on the biological parameters of H. hebetor measured in the current study. Meanwhile, this study provides a new method for the safety evaluation of the ectoparasitoids of target pest and might be expanded to the other species of ectoparasitoids of target insects of Cry proteins in biosafety risk assessment.


Assuntos
Proteínas de Bactérias/metabolismo , Endotoxinas/metabolismo , Hemolinfa/metabolismo , Proteínas Hemolisinas/metabolismo , Interações Hospedeiro-Parasita , Mariposas/metabolismo , Controle Biológico de Vetores/métodos , Vespas/metabolismo , Animais , Proteínas de Bactérias/genética , Endotoxinas/genética , Feminino , Fertilidade , Proteínas Hemolisinas/genética , Larva/metabolismo , Larva/parasitologia , Masculino , Mariposas/parasitologia , Oryza/genética , Plantas Geneticamente Modificadas/genética , Pupa/metabolismo , Vespas/crescimento & desenvolvimento
19.
Fish Shellfish Immunol ; 99: 190-198, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32058094

RESUMO

There has been extensive research on local and systemic oxidative stress and immunosuppression in cadmium exposed crustaceans, but the underlying mechanisms remain to be elucidated. Because of multiple functions of epithelial cells, such as storing and detoxifying heavy metals, producing and secreting immune-related molecules (i.e. hemocyanin, NF-κB and CBS/H2S et al.), hepatopancreas may play an important role in immune system. In the present study, as an indication of systemic and local immune status in crayfish Procambarus clarkii, the relationship between PO activities in haemolymph and levels of CBS/H2S/NF-κBp65 in hepatopancreas was evaluated following a 96 h exposure to sub-lethal Cd2+ concentrations (1/40, 1/8 and 1/4 of the 96 h LC50). The results indicated that there was a significant increase in ROS contents accompanied by markedly decreased THC and PO levels (P < 0.01) in a dose- and time- dependent manner. The evolutionarily conserved CBS and NF-κB p65 showed obvious difference (P < 0.01) (including cellular distribution and expression level) between the healthy and pathological conditions based on IHC analysis. Even small change of endogenous H2S content may be closely related to NF-κB p65 level and PO activity (P < 0.01). There was significantly negative correlation (P < 0.05) between PO activity and expression levels of CBS and NF-κB p65. Obviously, crayfish innate immunity was a highly complex network of various cells, molecules, and signaling pathways which operate, at least partly, through small signaling molecules such as H2S. ROS-mediated CBS/H2S/NF-κB pathway probably allowed hepatopancreas to inhibit PO activity under cadmium stress.


Assuntos
Astacoidea/imunologia , Cádmio/toxicidade , Hepatopâncreas/imunologia , Imunidade Inata , Monofenol Mono-Oxigenase/metabolismo , Animais , Astacoidea/efeitos dos fármacos , Hemolinfa/metabolismo , Hepatopâncreas/metabolismo , Masculino , Estresse Oxidativo , Transdução de Sinais , Fator de Transcrição RelA/metabolismo
20.
Mar Drugs ; 18(2)2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-32092907

RESUMO

Structure-based tissue engineering requires large-scale 3D cell/tissue manufacture technologies, to produce biologically active scaffolds. Special attention is currently paid to naturally pre-designed scaffolds found in skeletons of marine sponges, which represent a renewable resource of biomaterials. Here, an innovative approach to the production of mineralized scaffolds of natural origin is proposed. For the first time, a method to obtain calcium carbonate deposition ex vivo, using living mollusks hemolymph and a marine-sponge-derived template, is specifically described. For this purpose, the marine sponge Aplysin aarcheri and the terrestrial snail Cornu aspersum were selected as appropriate 3D chitinous scaffold and as hemolymph donor, respectively. The formation of calcium-based phase on the surface of chitinous matrix after its immersion into hemolymph was confirmed by Alizarin Red staining. A direct role of mollusks hemocytes is proposed in the creation of fine-tuned microenvironment necessary for calcification ex vivo. The X-ray diffraction pattern of the sample showed a high CaCO3 amorphous content. Raman spectroscopy evidenced also a crystalline component, with spectra corresponding to biogenic calcite. This study resulted in the development of a new biomimetic product based on ex vivo synthetized ACC and calcite tightly bound to the surface of 3D sponge chitin structure.


Assuntos
Quitina/análogos & derivados , Quitina/química , Hemolinfa/metabolismo , Poríferos/metabolismo , Caramujos/metabolismo , Tecidos Suporte , Animais , Biomineralização , Carbonato de Cálcio/química , Difração de Raios X
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