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1.
J Invertebr Pathol ; 185: 107672, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34597621

RESUMO

Nosema ceranae is an intracellular microsporidian pathogen that lives in the midgut ventricular cells of all known honey bee Apis species. We suspect that N. ceranae may also cause energetic stress in the giant honey bee because this parasite is known to disrupt nutrient absorption resulting in energetic stress in the honey bee species Apis mellifera. To understand how N. ceranae impacts the energetic stress of the giant honey bee, A. dorsata, we measured the hemolymph trehalose levels of experimentally infected giant honey bees on days three, five, seven, and fourteen post infection (p.i.). We also measured the hypopharyngeal gland protein content, the total midgut proteolytic enzyme activity, honey bee survival, infection ratio, and spore loads comparing infected and uninfected honey bees across the same time frame. Nosema ceranae-infected honey bees had significantly lowered survival, trehalose levels, hypopharyngeal gland protein content, and midgut proteolytic enzyme activity. We found an increasing level of parasitic loads and infection ratio of N. ceranae-infected bees after inoculation. Collectively, our results suggest that the giant honey bee suffers from energetic stress and limited nutrient absorption from a N. ceranae infection, which results in lowered survival in comparison to uninfected honey bees. Our findings highlight that other honey bee species besides A. mellifera are susceptible to microsporidian pathogens that they harbor, which results in negative effects on health and survival. Therefore, these pathogens might be transmitted at a community level, in the natural environment, resulting in negative health effects of multiple honey bee species.


Assuntos
Abelhas/microbiologia , Hemolinfa/microbiologia , Nosema/fisiologia , Nutrientes/fisiologia , Absorção Fisiológica , Aminoácidos/fisiologia , Animais , Trato Gastrointestinal/enzimologia , Trato Gastrointestinal/microbiologia , Longevidade , Esporos Fúngicos/fisiologia
2.
Front Immunol ; 12: 685896, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34295333

RESUMO

In recent years, more and more studies have shown that early pathogenic bacterial infection in invertebrates can enhance immunity and significantly reduce mortality when reinfected with the same pathogen. There are mechanisms to explain this phenomenon, but they are relatively few. In addition, dose-dependent primary infection is also associated with increased immunity. In the present study, the initial infection dose and mortality of abalone Haliotis diversicolor after reinfection with Vibrio harveyi were recorded, and the mechanism of immune enhancement was investigated by the transcriptomic response of abalone after two successive stimuli with V. harveyi. Priming with different concentrations of pathogen can enhance immunity; however, higher concentration is not always better. Compared with the first exposure, more genes were up-regulated after the second exposure. Among the commonly expressed genes, the immune related genes were significantly or persistently highly expressed after two infections and included pattern recognition receptors as well as immune effectors, such as toll-like receptors, perlucin 4, scavenger receptor class B-like protein, cytochrome P450 1B1-like, glutathione S-transferase 6, lysozyme and so on; in addition, these immune-related genes were mainly distributed in the pathways related to phagocytosis and calcium signaling. Among the specifically expressed genes, compared with the first infection, more genes were involved in the immune, metabolic and digestive pathways after the second infection, which would be more conducive to preventing the invasion of pathogens. This study outlined the mechanism of immune enhancement in abalone after secondary infection at the global molecular level, which is helpful for a comprehensive understanding of the mechanism of immune priming in invertebrates.


Assuntos
Gastrópodes/genética , Gastrópodes/imunologia , Gastrópodes/microbiologia , Vibrioses/imunologia , Vibrio/fisiologia , Animais , Regulação da Expressão Gênica , Hemolinfa/microbiologia , Imunidade , Imunomodulação
3.
Mar Biotechnol (NY) ; 23(3): 463-471, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34076776

RESUMO

Studies of invertebrates have shown that the internal environment of crustaceans is not always sterile in normal conditions, and in many species, it can be populated by microorganisms even in the absence of any visible pathological processes in the body. This observation raises the question of whether genetically modified indigenous hemolymph microorganisms can be used for biotechnological purposes inside the crustacean either as local producers of some compounds or as sensors to physiological parameters. In this study, we tested the ability of the bacteria isolated from the hemolymph of the amphipod Eulimnogammarus verrucosus to hide from the cellular immune response of the host as the most important feature for their potential long-term application in vivo. 16S rDNA amplicon sequencing revealed five common bacterial genera in all analyzed samples of the amphipod hemolymph, among which Pseudomonas is most easily subjected to genome modification and, thus, the most prospective for biotechnological application. Cultivation of Pseudomonas gave us a number of strains undoubtedly derived from the amphipod hemolymph, and one of them (belonging to the Pseudomonas fluorescens group) was chosen for further tests. The primary culture of amphipod hemocytes was used to analyze the immunogenicity of the strain and showed a pronounced reaction of the immune cells to a high amount of the bacteria within six hours. This result indicates that modulation of cellular immune response to metabolically active bacterial cells is not mandatory for the survival and wide distribution of these microorganisms in the hemolymph of numerous amphipod individuals.


Assuntos
Anfípodes/imunologia , Anfípodes/microbiologia , Imunidade Celular , Pseudomonas/fisiologia , Animais , Hemócitos , Hemolinfa/citologia , Hemolinfa/microbiologia , Lagos , Sibéria
4.
Arch Microbiol ; 203(7): 4461-4473, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34142183

RESUMO

A cultivated form of bacteria (strain 2202) was isolated from the hemal fluid of the bivalve mollusk Modiolus kurilensis. Based on the set of data collected by genetic and physiological/biochemical analyses, the strain was identified as the species Pseudoalteromonas piscicida. Strain 2202 exhibits antimicrobial activity against Staphylococcus aureus, Candida albicans, and Bacillus subtilis but not against Escherichia coli and Pseudomonas aeruginosa. These activities characterize the behavior of strain 2202 as predator-like and classify it as a facultative predator. Being part of the normal microflora in the hemolymph of M. kurilensis, when external conditions change, strain 2202 shows features of opportunistic microflora. The strain 2202 exhibits selective toxicity towards larvae of various invertebrates: it impairs the early development of Mytilus edulis, but not of Strongylocentrotus nudus. Thus, the selective manner in which P. piscicida strains interact with various species of microorganisms and eukaryotes should be taken into consideration when using their biotechnological potential as a probiotic in aquaculture, source of antimicrobial substances, and factors that prevent fouling.


Assuntos
Bivalves , Pseudoalteromonas , Animais , Fenômenos Fisiológicos Bacterianos , Bivalves/microbiologia , Candida/fisiologia , Hemolinfa/microbiologia , Interações Microbianas , Pseudoalteromonas/isolamento & purificação , Pseudoalteromonas/metabolismo , Pseudoalteromonas/fisiologia
5.
Sci Rep ; 11(1): 10971, 2021 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-34040020

RESUMO

Microsporidia are naturally occurring fungal-related parasites that can infect nearly all animal hosts, but their biocontrol potential of insect pests is routinely overlooked in agriculture and forestry. This research brings the first report describing the natural occurrence of a microsporidium causing disease in field-collected populations of the invasive eucalyptus snout beetle, Gonipterus platensis (Coleoptera: Curculionidae), a major destructive pest of eucalyptus plantations in Brazil. Adult beetles were collected during field surveys in commercial eucalyptus plantations in southern Brazil to be examined and dissected with typical symptoms to verify presence of microsporidian spores in haemolymph. From 14 plantations in different sites, the natural infection occurrence in these populations ranged from 0 to 65%, while a lab colony exhibited an infection incidence of 70%. Spore density in haemolymph of symptomatic insects averaged 2.1 (± 0.4) × 107 spores/beetle. Symptoms in infected adults were identified by an abnormal abdomen with malformation of the second pair of wings, impairing their flight activity. Electron transmission microscopy of the pathogen showed morphological features similar to species belonging to the genus Nosema or Vairimorpha. Phylogenetic analysis of the full-length small subunit ribosomal RNA gene suggests this pathogen's placement in the genus Vairimorpha, but with a sequence identity of ~ 94% with the nearest neighbours. The low level of sequence identity suggests this pathogen may represent a novel taxon in the genus and further requires whole genome sequencing for definitive taxonomic resolution. These findings provide insights on the natural occurrence of this novel pathogen of this invasive pest in Eucalyptus plantations in Brazil. Further studies are needed to determine potential of this microsporidium in the design of conservative or augmentative biological control programs for this invasive pest.


Assuntos
Besouros/microbiologia , Microsporídios não Classificados/isolamento & purificação , Animais , Brasil , Eucalyptus , Hemolinfa/microbiologia , Microsporídios não Classificados/classificação , Microsporídios não Classificados/genética , Microsporídios não Classificados/patogenicidade , Filogenia , RNA Fúngico/genética , RNA Ribossômico/genética , Especificidade da Espécie
6.
Front Immunol ; 12: 659723, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33868309

RESUMO

The "milky disease" of the Chinese mitten crab, Eriocheir sinensis, is a highly lethal fungal disease caused by Metschnikowia bicuspidata infection. To elucidate the immune responses of the hemolymph of E. sinensis to M. bicuspidata infection, a comparative analysis of the hemolymph of E. sinensis infected with M. bicuspidata and that treated with phosphate buffered saline was performed using label-free quantitative proteomics. A total of 429 proteins were identified. Using a 1.5-fold change in expression as a physiologically significant benchmark, 62 differentially expressed proteins were identified, of which 38 were significantly upregulated and 24 were significantly downregulated. The upregulated proteins mainly included cytoskeleton-related proteins (myosin regulatory light chain 2, myosin light chain alkali, tubulin α-2 chain, and tubulin ß-1 chain), serine protease and serine protease inhibitor (clip domain-containing serine protease, leukocyte elastase inhibitor, serine protein inhibitor 42Dd), catalase, transferrin, and heat shock protein 70. Upregulation of these proteins indicated that phenoloxidase system, phagocytosis and the ROS systems were induced by M. bicuspidata. The downregulated proteins were mainly organ and tissue regeneration proteins (PDGF/VEGF-related factor protein, integrin-linked protein kinase homing pat-4 gene) and hemagglutination-associated proteins (hemolymph clottable protein, hemocyte protein-glutamine gamma-glutamyltransferase). Downregulation of these proteins indicated that M. bicuspidata inhibited hemocyte regeneration and hemolymph agglutination. Fifteen differentially expressed proteins related to immunity were verified using a parallel reaction monitoring method. The expression trend of these proteins was similar to that of the proteome. To the best of our knowledge, this is the first report on the proteome of E. sinensis in response to M. bicuspidata infection. These results not only provide new and important information on the immune response of crustaceans to yeast infection but also provide a basis for further understanding the molecular mechanism of complex host pathogen interactions between crustaceans and fungi.


Assuntos
Proteínas de Artrópodes/metabolismo , Braquiúros/metabolismo , Hemolinfa/metabolismo , Proteoma/metabolismo , Proteômica/métodos , Animais , Proteínas de Artrópodes/genética , Proteínas de Artrópodes/isolamento & purificação , Braquiúros/genética , Braquiúros/microbiologia , China , Cromatografia Líquida/métodos , Feminino , Regulação da Expressão Gênica , Ontologia Genética , Hemolinfa/microbiologia , Interações Hospedeiro-Patógeno , Masculino , Metschnikowia/fisiologia , Proteoma/genética , Espectrometria de Massas em Tandem/métodos
7.
PLoS One ; 16(4): e0250524, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33914801

RESUMO

Insects are frequently infected with heritable bacterial endosymbionts. Endosymbionts have a dramatic impact on their host physiology and evolution. Their tissue distribution is variable with some species being housed intracellularly, some extracellularly and some having a mixed lifestyle. The impact of extracellular endosymbionts on the biofluids they colonize (e.g. insect hemolymph) is however difficult to appreciate because biofluid composition can depend on the contribution of numerous tissues. Here we investigate Drosophila hemolymph proteome changes in response to the infection with the endosymbiont Spiroplasma poulsonii. S. poulsonii inhabits the fly hemolymph and gets vertically transmitted over generations by hijacking the oogenesis in females. Using dual proteomics on infected hemolymph, we uncovered a weak, chronic activation of the Toll immune pathway by S. poulsonii that was previously undetected by transcriptomics-based approaches. Using Drosophila genetics, we also identified candidate proteins putatively involved in controlling S. poulsonii growth. Last, we also provide a deep proteome of S. poulsonii, which, in combination with previously published transcriptomics data, improves our understanding of the post-transcriptional regulations operating in this bacterium.


Assuntos
Drosophila melanogaster/genética , Proteoma/genética , Proteômica , Spiroplasma/genética , Animais , Proteínas de Bactérias/genética , Drosophila melanogaster/imunologia , Drosophila melanogaster/microbiologia , Feminino , Hemolinfa/microbiologia , Oogênese/genética , Transdução de Sinais/genética , Transdução de Sinais/imunologia , Spiroplasma/patogenicidade , Simbiose/genética , Simbiose/imunologia
8.
Fungal Genet Biol ; 150: 103508, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33675988

RESUMO

The pathogenicity of Metarhizium rileyi is a multi-faceted process that depends on many factors. This study attempts to decipher those factors of M. rileyi by investigating its pathogenicity against Spodoptera litura (Lepidoptera: Noctuidae) larvae. Through morphogenesis analysis, we for the first time demonstrated the infection structure, appressorium, of M. rileyi that can generate a more than 4 MPa turgor pressure. The Mrpmk1 gene was found to be essential for appressorium differentiation and mycelium reemerging, ΔMrpmk1 mutant exhibited no pathogenicity towards S. litura by natural infection process. Delayed appressorium formation time, decreased appressorium formation rate and turgor pressure of ΔMrpbs2 mutant manifested itself in postponed death time and lower mortality against S. litura. Following invasion into the larval hemocoel, M. rileyi cells transformed into blastospores, which may be conducive to dispersal and propagation, moreover, the blastospore form M. rileyi may subverted phagocytic defenses. Then M. rileyi cells morphed into extended hyphal body to cope with elongated hemocytes that participated in encapsulation. In the end, M. rileyi mycelia reemerged from the larval cadaver evenly to form muscardine cadaver. Eventually, conidia were produced to complete the infection cycle. During the infection, M. rileyi triggered both cellular and humoral immunity of S. litura. Besides morphological changes, stage-specifically produced oxalic acid and F-actin arrangement may play roles in nutrient acquisition and mycelium reemerging, respectively.


Assuntos
Proliferação de Células , Hemolinfa/microbiologia , Larva/imunologia , Larva/fisiologia , Metarhizium/patogenicidade , Micélio/crescimento & desenvolvimento , Spodoptera/fisiologia , Animais , Imunidade Celular , Imunidade Humoral , Metarhizium/genética , Metarhizium/crescimento & desenvolvimento , Spodoptera/imunologia , Virulência
9.
Arch Microbiol ; 203(3): 1251-1258, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33128575

RESUMO

Nonribosomal peptide synthetases (NRPS) are multi-domain enzymes that have innumerably beneficial health applications. Realizing the significance of marine microorganisms in search for NRPS sequences, study was conducted for analysis of NRPS gene sequences of marine crab haemolymph bacteria for the first time. Strains belonging to five different species were found to have NRPS genes. The study generated NRPS sequences from four bacterial species, for which NRPS gene information was not available earlier. Two new putative adenylation domain signatures were identified from phylum Firmicutes. In silico analysis of amino acid sequences from four species showed less identity (42-50%) to the characterized NRPS compounds that integrate serine residue in active site, suggesting the novelty or uncharacterized nature. Altogether, the study warrants future research exploiting marine crab haemolymph bacteria, an unexplored niche of microbial genetic wealth to discover microbial novel NRPS genes and natural products using emerging tools and technologies.


Assuntos
Bactérias/genética , Braquiúros/microbiologia , Peptídeo Sintases/genética , Peptídeo Sintases/metabolismo , Sequência de Aminoácidos , Animais , Bactérias/enzimologia , Hemolinfa/microbiologia
10.
Front Immunol ; 11: 599625, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33281827

RESUMO

The interaction between host immune response and the associated microbiota has recently become a fundamental aspect of vertebrate and invertebrate animal health. This interaction allows the specific association of microbial communities, which participate in a variety of processes in the host including protection against pathogens. Marine aquatic invertebrates such as scallops are also colonized by diverse microbial communities. Scallops remain healthy most of the time, and in general, only a few species are fatally affected on adult stage by viral and bacterial pathogens. Still, high mortalities at larval stages are widely reported and they are associated with pathogenic Vibrio. Thus, to give new insights into the interaction between scallop immune response and its associated microbiota, we assessed the involvement of two host antimicrobial effectors in shaping the abundances of bacterial communities present in the scallop Argopecten purpuratus hemolymph. To do this, we first characterized the microbiota composition in the hemolymph from non-stimulated scallops, finding both common and distinct bacterial communities dominated by the Proteobacteria, Spirochaetes and Bacteroidetes phyla. Next, we identified dynamic shifts of certain bacterial communities in the scallop hemolymph along immune response progression, where host antimicrobial effectors were expressed at basal level and early induced after a bacterial challenge. Finally, the transcript silencing of the antimicrobial peptide big defensin ApBD1 and the bactericidal/permeability-increasing protein ApLBP/BPI1 by RNA interference led to an imbalance of target bacterial groups from scallop hemolymph. Specifically, a significant increase in the class Gammaproteobacteria and the proliferation of Vibrio spp. was observed in scallops silenced for each antimicrobial. Overall, our results strongly suggest that scallop antimicrobial peptides and proteins are implicated in the maintenance of microbial homeostasis and are key molecules in orchestrating host-microbiota interactions. This new evidence depicts the delicate balance that exists between the immune response of A. purpuratus and the hemolymph microbiota.


Assuntos
Regulação da Expressão Gênica/imunologia , Hemócitos , Hemolinfa , Microbiota/imunologia , Pectinidae , Vibrio/imunologia , Animais , Forma Celular/imunologia , Hemócitos/citologia , Hemócitos/imunologia , Hemócitos/microbiologia , Hemolinfa/citologia , Hemolinfa/imunologia , Hemolinfa/microbiologia , Pectinidae/citologia , Pectinidae/imunologia , Pectinidae/microbiologia
11.
Mar Drugs ; 18(12)2020 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-33321943

RESUMO

Discovery after discovery, host-associated microbiota reveal a growing list of positive effects on host homeostasis by contributing to host nutrition, improving hosts' immune systems and protecting hosts against pathogens. In that context, a collection of oyster associated bacteria producing antibacterial compounds have been established to evaluate their role in non-host-derived immunity. Here, we described alterins; potent anti-Gram negative compounds produced by Pseudoalteromonas hCg-6 and hCg-42 isolated from different healthy oyster hemolymph. The strains hCg-6 and hCg-42 produce a set of at least seven antibacterial compounds, ranging from 926 to 982 Da structurally characterized as cyclolipopeptides (CLPs). Alterins share the same cationic heptapeptidic cycle connected via an amido bond to different hydrophobic hydrocarbon tails. Their MICs disclosed a potent antibacterial activity directed against Gram-negative bacteria including oyster and human pathogens that may confer a beneficial defense mechanism to the host but also represents an untapped source of new antibiotics. The alterins' mechanisms of action have been deciphered: after binding to lipopolysaccharides (LPS), alterins provoke a membrane depolarization and permeabilization leading to bacterial lysis. As hCg-6 and hCg-42 produced a set of natural derivatives, the structure/activity relationship linked to the carbon tail is clarified. We showed that the hydrocarbon tail determines the LPS-binding properties of alterins and consequently their antibacterial activities. Its length and saturation seem to play a major role in this interaction.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Lipopeptídeos/farmacologia , Lipopolissacarídeos/metabolismo , Ostreidae/microbiologia , Peptídeos Cíclicos/farmacologia , Pseudoalteromonas/metabolismo , Animais , Antibacterianos/isolamento & purificação , Antibacterianos/metabolismo , Peptídeos Catiônicos Antimicrobianos/isolamento & purificação , Peptídeos Catiônicos Antimicrobianos/metabolismo , Bactérias Gram-Negativas/crescimento & desenvolvimento , Hemolinfa/microbiologia , Interações Hospedeiro-Patógeno , Lipopeptídeos/isolamento & purificação , Lipopeptídeos/metabolismo , Testes de Sensibilidade Microbiana , Peptídeos Cíclicos/isolamento & purificação , Peptídeos Cíclicos/metabolismo , Relação Estrutura-Atividade
12.
Environ Microbiol ; 22(12): 5450-5466, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33169917

RESUMO

The microbiome - the microorganism community that is found on or within an organism's body - is increasingly recognized to shape many aspects of its host biology and is a key determinant of health and disease. Microbiomes modulate the capacity of insect disease vectors (mosquitoes, tsetse flies, sandflies) to transmit parasites and disease. We investigate the diversity and abundance of microorganisms within the hemolymph (i.e. blood) of Biomphalaria snails, the intermediate host for Schistosoma mansoni, using Illumina MiSeq sequencing of the bacterial 16S V4 rDNA. We sampled hemolymph from five snails from six different laboratory populations of B. glabrata and one population of B. alexandrina. We observed 279.84 ± 0.79 amplicon sequence variants per snail. There were significant differences in microbiome composition at the level of individual snails, snail populations and species. Snail microbiomes were dominated by Proteobacteria and Bacteroidetes while water microbiomes from snail tank were dominated by Actinobacteria. We investigated the absolute bacterial load using qPCR: hemolymph samples contained 2784 ± 339 bacteria/µl. We speculate that the microbiome may represent a critical, but unexplored intermediary in the snail-schistosome interaction as hemolymph is in very close contact with the parasite at each step of its development.


Assuntos
Biomphalaria/microbiologia , Vetores de Doenças , Hemolinfa/microbiologia , Microbiota , Esquistossomose/transmissão , Animais , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Biomphalaria/classificação , Especificidade de Hospedeiro , RNA Ribossômico 16S/genética , Schistosoma mansoni/fisiologia
13.
Molecules ; 25(21)2020 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-33137930

RESUMO

Berberine is an alkaloid of the protoberberine type used in traditional oriental medicine. Its biological activities include documented antibacterial properties against a wide variety of microorganisms; nonetheless, its use against Escherichia coli strains isolated from urinary infections has not yet been widely investigated in vivo. The emergence of antimicrobial resistance requires new therapeutic approaches to ensure the continued effectiveness of antibiotics for the treatment and prevention of urinary infections. Moreover, uropathogenic Escherichia coli (UPEC) has developed several virulence factors and resistance to routine antibiotic therapy. To this end, several in vitro and in vivo tests were conducted to assess the activity of berberine on uropathogenic E. coli strains. Galleria mellonella as an infection model was employed to confirm the in vivo translatability of in vitro data on berberine activity and its influence on adhesion and invasion proprieties of E. coli on human bladder cells. In vitro pre-treatment with berberine was able to decrease the adhesive and invasive UPEC ability. In vivo treatment increased the larvae survival infected with UPEC strains and reduced the number of circulating pathogens in larvae hemolymph. These preliminary findings demonstrated the efficacy and reliability of G. mellonella as in vivo model for pre-clinical studies of natural substances.


Assuntos
Antibacterianos/farmacologia , Berberina/farmacologia , Infecções por Escherichia coli , Mariposas/microbiologia , Escherichia coli Uropatogênica/crescimento & desenvolvimento , Animais , Modelos Animais de Doenças , Infecções por Escherichia coli/tratamento farmacológico , Infecções por Escherichia coli/metabolismo , Hemolinfa/microbiologia , Larva
14.
Arch Insect Biochem Physiol ; 105(4): e21747, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33029869

RESUMO

All living things on Earth experience various diseases such as those caused by viruses, bacteria, and fungi. Insects are no exception to this rule, and fungi that cause disease in insects are called entomopathogenic fungi. These fungi have been developed as microbial insecticides and are used to control various pests. Generally, the mode of action of entomopathogenic fungi is divided into the attachment of conidia, germination, penetration, growth, and generation of secondary infectious conidia. In each of these steps, that entomopathogenic fungi use genes in a complex manner (specific or diverse) has been shown by gene knock-out and RNA-sequencing analysis. In this review, the information mechanism of entomopathogenic fungi was divided into six steps: (1) attachment of conidia to host, (2) germination and appressorium, (3) penetration, (4) fungal growth in hemolymph, (5) conidia production on host, and (6) transmission and dispersal. The strategy used by the fungi in each step was described at the genetic level. In addition, an approach for studying the mode of action of the fungi is presented.


Assuntos
Fungos/genética , Fungos/patogenicidade , Insetos/microbiologia , Animais , Fungos/crescimento & desenvolvimento , Hemolinfa/microbiologia , Controle Biológico de Vetores , Esporos Fúngicos/crescimento & desenvolvimento
15.
Immunol Cell Biol ; 98(9): 757-769, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32623757

RESUMO

The immune blood cells "hemocytes" of mosquitoes impart a highly selective immune response against various microorganisms/pathogens. Among several immune effectors, fibrinogen-related proteins (FREPs) have been recognized as key modulators of cellular immune responses; however, their physiological relevance has not been investigated in detail. Our ongoing comparative RNA-sequencing analysis identified a total of 13 FREPs originating from naïve sugar-fed, blood-fed, bacterial challenged and Plasmodium vivax-infected hemocytes in Anopheles stephensi. Transcriptional profiling of the selected seven FREP transcripts showed distinct responses against different pathophysiological conditions, where an exclusive induction of FREP12 after 10 days of P. vivax infection was observed. This represents a possible role of FREP12 in immunity against free circulating sporozoites and needs to be explored in the future. When challenged with live bacterial injection in the thorax, we observed a higher affinity of FREP13 and FREP65 toward Gram-negative and Gram-positive bacteria in the mosquito hemocytes, respectively. Furthermore, we observed increased bacterial survival and proliferation, which is likely compromised by the downregulation of TEP1, in FREP13 messenger RNA-depleted mosquito hemolymph. In contrast, after blood-feeding, we also noticed a significant delay of 24 h in the enrichment of gut endosymbionts in the FREP13-silenced mosquitoes. Taken together, we conclude that hemocyte-specific FREP13 carries the unique ability of tissue-specific regulation, having an antagonistic antibacterial role in the hemolymph, and an agonistic role against gut endosymbionts.


Assuntos
Anopheles , Microbioma Gastrointestinal , Hemócitos/parasitologia , Hemolinfa/microbiologia , Proteínas de Insetos/genética , Animais , Anopheles/imunologia , Bactérias , Plasmodium vivax , Esporozoítos , Simbiose
16.
Mol Biochem Parasitol ; 238: 111298, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32621939

RESUMO

Endosymbiotic bacteria that obligately associate with entomopathogenic nematodes as a complex are a unique model system to study competition. These nematodes seek an insect host and provide entry for their endosymbionts. Through their natural products, the endosymbionts nurture their nematodes by eliminating secondary infection, providing nutrients through bioconversion of the insect cadaver, and facilitating reproduction. On one hand, they cooperatively colonize the insect host and neutralize other opportunistic biotic threats. On the other hand, inside the insect cadaver as a fighting pit, they fiercely compete for the fittest partnership that will grant them the reproductive dominance. Here, we review the protective and nurturing nature of endosymbiotic bacteria for their nematodes and how their selective preference shapes the superior nematode-endosymbiont pairs as we know today.


Assuntos
Bactérias/metabolismo , Fatores Biológicos/biossíntese , Insetos/parasitologia , Nematoides/microbiologia , Infecções por Nematoides/parasitologia , Simbiose/fisiologia , Animais , Bactérias/crescimento & desenvolvimento , Catecol Oxidase/metabolismo , Precursores Enzimáticos/metabolismo , Proteínas de Helminto/metabolismo , Hemolinfa/microbiologia , Hemolinfa/parasitologia , Insetos/microbiologia , Nematoides/enzimologia , Nematoides/patogenicidade , Infecções por Nematoides/microbiologia , Fosfolipases A2/metabolismo
17.
mBio ; 11(4)2020 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-32665268

RESUMO

Beneficial microorganisms associated with animals derive their nutritional requirements entirely from the animal host, but the impact of these microorganisms on host metabolism is largely unknown. The focus of this study was the experimentally tractable tripartite symbiosis between the pea aphid Acyrthosiphon pisum, its obligate intracellular bacterial symbiont Buchnera, and the facultative bacterium Hamiltonella which is localized primarily to the aphid hemolymph (blood). Metabolome experiments on, first, multiple aphid genotypes that naturally bear or lack Hamiltonella and, second, one aphid genotype from which Hamiltonella was experimentally eliminated revealed no significant effects of Hamiltonella on aphid metabolite profiles, indicating that Hamiltonella does not cause major reconfiguration of host metabolism. However, the titer of just one metabolite, 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), displayed near-significant enrichment in Hamiltonella-positive aphids in both metabolome experiments. AICAR is a by-product of biosynthesis of the essential amino acid histidine in Buchnera and, hence, an index of histidine biosynthetic rates, suggesting that Buchnera-mediated histidine production is elevated in Hamiltonella-bearing aphids. Consistent with this prediction, aphids fed on [13C]histidine yielded a significantly elevated 12C/13C ratio of histidine in Hamiltonella-bearing aphids, indicative of increased (∼25%) histidine synthesized de novo by Buchnera However, in silico analysis predicted an increase of only 0.8% in Buchnera histidine synthesis in Hamiltonella-bearing aphids. We hypothesize that Hamiltonella imposes increased host demand for histidine, possibly for heightened immune-related functions. These results demonstrate that facultative bacteria can alter the dynamics of host metabolic interactions with co-occurring microorganisms, even when the overall metabolic homeostasis of the host is not substantially perturbed.IMPORTANCE Although microbial colonization of the internal tissues of animals generally causes septicemia and death, various animals are persistently associated with benign or beneficial microorganisms in their blood or internal organs. The metabolic consequences of these persistent associations for the animal host are largely unknown. Our research on the facultative bacterium Hamiltonella, localized primarily to the hemolymph of pea aphids, demonstrated that although Hamiltonella imposed no major reconfiguration of the aphid metabolome, it did alter the metabolic relations between the aphid and its obligate intracellular symbiont, Buchnera Specifically, Buchnera produced more histidine in Hamiltonella-positive aphids to support both Hamiltonella demand for histidine and Hamiltonella-induced increase in host demand. This study demonstrates how microorganisms associated with internal tissues of animals can influence specific aspects of metabolic interactions between the animal host and co-occurring microorganisms.


Assuntos
Afídeos/metabolismo , Afídeos/microbiologia , Bactérias/metabolismo , Interações entre Hospedeiro e Microrganismos , Simbiose , Animais , Buchnera/metabolismo , Feminino , Genótipo , Hemolinfa/microbiologia , Histidina/metabolismo , Metabolômica
18.
Fish Shellfish Immunol ; 104: 252-261, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32497727

RESUMO

Activating transcription factors 2 (ATF2) is a transcription factor of the members of ATF/CREB family that is phosphorylated and activated by the mitogen-activated protein kinase (MAPK) in responding to the stimulation of stimuli. In present study, SpATF2 from mud crab (Scylla paramamosain) was identified and studied. The open reading frame of SpATF2 with 2136 bp in length encodes a protein with 711 amino acids. The SpATF2 protein includes the putative zinc finger domain in the N-terminus and bZIP type DNA-binding domain in the C-terminal. Tissue distribution of SpATF2 transcripts showed that SpATF2 was ubiquitously expressed in all examined tissues of the untreated mud crabs, with the highest expression levels in muscle and hepatopancreas. The transcriptional level of SpATF2 was up-regulated in the hemocytes after Vibrio parahemolyticus or WSSV infection. Reporter gene assays indicated that SpATF2 could activate the expression of dual oxidase (SpDuox1) in S. paramamosain. The RNA interference (RNAi) of SpATF2 significantly decreased the expression of SpDuox1, and consequently reduced reactive oxygen species production thereby significantly increased the bacterial load in the hemolymph of mud crabs. Similarly, significant reduction in bacterial clearance of hemolymph was observed after the V. parahemolyticus infection in SpATF2 knockdown mud crabs. This study showed that SpATF2 played a vital role in maintaining homeostasis of the hemolymph microbiota through regulating the expression of dual oxidase of mud crab.


Assuntos
Fator 2 Ativador da Transcrição/imunologia , Proteínas de Artrópodes/imunologia , Braquiúros/imunologia , Braquiúros/microbiologia , Hemolinfa/microbiologia , Microbiota , Fator 2 Ativador da Transcrição/genética , Animais , Proteínas de Artrópodes/genética , Hemócitos/metabolismo , Hemolinfa/imunologia , Homeostase , Interferência de RNA , Espécies Reativas de Oxigênio/metabolismo
19.
Environ Microbiol ; 22(10): 4323-4341, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32363732

RESUMO

In the marine environment, bivalve mollusks constitute habitats for bacteria of the Vibrionaceae family. Vibrios belong to the microbiota of healthy oysters and mussels, which have the ability to concentrate bacteria in their tissues and body fluids, including the hemolymph. Remarkably, these important aquaculture species respond differently to infectious diseases. While oysters are the subject of recurrent mass mortalities at different life stages, mussels appear rather resistant to infections. Thus, Vibrio species are associated with the main diseases affecting the worldwide oyster production. Here, we review the current knowledge on Vibrio-bivalve interaction in oysters (Crassostrea sp.) and mussels (Mytilus sp.). We discuss the transient versus stable associations of vibrios with their bivalve hosts as well as technical issues limiting the monitoring of these bacteria in bivalve health and disease. Based on the current knowledge of oyster/mussel immunity and their interactions with Vibrio species pathogenic for oyster, we discuss how differences in immune effectors could contribute to the higher resistance of mussels to infections. Finally, we review the multiple strategies evolved by pathogenic vibrios to circumvent the potent immune defences of bivalves and how key virulence mechanisms could have been positively or negatively selected in the marine environment through interactions with predators.


Assuntos
Crassostrea/microbiologia , Interações Hospedeiro-Patógeno/imunologia , Mytilus/microbiologia , Vibrio/patogenicidade , Animais , Crassostrea/imunologia , Hemolinfa/microbiologia , Interações Hospedeiro-Patógeno/fisiologia , Microbiota , Mytilus/imunologia , Vibrio/imunologia
20.
Dev Comp Immunol ; 109: 103701, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32320738

RESUMO

Cell mediated immunity of the honey bee (Apis mellifera) involves the activity of several hemocyte populations, currently defined by morphological features and lectin binding characteristics. The objective of the present study was to identify molecular markers capable of characterizing subsets of honey bee hemocytes. We developed and employed monoclonal antibodies with restricted reactions to functionally distinct hemocyte subpopulations. Melanizing cells, known as oenocytoids, were defined by an antibody to prophenoloxidase, aggregating cells were identified by the expression of Hemolectin, and phagocytic cells were identified by a marker expressed on granulocytes. We anticipate that this combination of antibodies not only allows for the detection of functionally distinct hemocyte subtypes, but will help to further the exploration of hematopoietic compartments, as well as reveal details of the honey bee cellular immune defense against parasites and microbes.


Assuntos
Anticorpos Monoclonais/imunologia , Abelhas/imunologia , Hemócitos/imunologia , Hemolinfa/imunologia , Animais , Anticorpos Monoclonais/análise , Abelhas/citologia , Abelhas/microbiologia , Biomarcadores/análise , Escherichia coli/imunologia , Hemócitos/citologia , Hemócitos/microbiologia , Hemolinfa/citologia , Hemolinfa/microbiologia , Larva/citologia , Larva/imunologia , Larva/microbiologia , Microscopia de Fluorescência , Fagocitose/imunologia
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