Influence of temperature on the infectivity of entomopathogenic nematodes (Steinernema and Heterorhabditis spp.) to larvae and pupae of the vine weevil Otiorhynchus sulcatus (Coleoptera: Curculionidae)

Nematology ◽  
2000 ◽  
Vol 2 (3) ◽  
pp. 309-317 ◽  
Author(s):  
Steve Long ◽  
John Fenlon ◽  
Paul Richardson
Keyword(s):  
Competing Risks ◽  
Entomopathogenic Nematodes ◽  
Galleria Mellonella ◽  
Commercial Product ◽  
Effect Of Temperature ◽  
Heterorhabditis Megidis ◽  
Otiorhynchus Sulcatus ◽  
The Uk

AbstractThe susceptibilities of early and late instar vine weevil larvae and pupae to three species of entomopathogenic nematodes, indigenous to the UK, were tested in a series of bioassays. Steinernema kraussei (isolates L017 and L137), S. feltiae (the commercial product Nemasys®) and Heterorhabditis megidis (the commercial product Nemasys® H, reared both in vivo in Galleria mellonella larvae and in vitro), were tested at 6, 10 and 18°C for 2 weeks (early instars of O. sulcatus) or 3 weeks (late instars and pupae of O. sulcatus). Nematodes were applied to over 3800 larvae or pupae and there were over 400 untreated controls. Each insect was examined subsequently to determine mortality, and parasitised specimens were dissected to establish whether adult nematodes had developed. Differences in pathogenicity between H. megidis reared in vitro and in vivo were demonstrated. S. kraussei (L137) was consistently the most virulent nematode isolate at low temperatures. The results revealed a significant (P < 0.001) effect of temperature on small larvae of O. sulcatus, but also showed differential levels of mortality, not due to nematodes, for both small larvae and pupae. The use of Abbott's correction for control mortality is challenged and the validity of competing risks theory examined.In einer Reihe von Biotests wurde die Anfälligkeit von frühen und späten Larvenstadien sowie Puppen des Rüsselkäfers Otiorhynchus sulcatus gegenüber drei in UK einheimischen entomopathogenen Nematoden untersucht. Steinernema kraussei (isolate L017 und L137), S. feltiae (Handelsprodukt Nemasys®) und Heterorhabditis megidis (Handelsprodukt Nemasys® H, beide in vivo an Larven von Galleria mellonella und in vitro gezüchtet) wurden bei 6, 10 and 18°C für zwei Wochen (frühe Stadien von O. sulcatus) oder drei Wochen (späte Stadien und Puppen von O. sulcatus) geprüft. Über 3800 Larven oder Puppen wurden mit Nematoden behandelt, daneben gab es über 400 unbehandelte Kontrollen. Anschliessend wurde jedes Insekt untersucht, um die Mortalität zu bestimmen. Parasitierte Exemplare wurden aufpräpariert um festzustellen, ob sich adulte Nematoden entwickelt hatten. Zwischen in vitro und in vivo kultivierten H. megidis konnten Unterschiede in der Pathogenität festgestellt werden. S. kraussei (L137) war bei niedrigen Temperaturen durchgehend das virulenteste Isolat. Die Ergebnisse zeigten eine signifikante (P < 0.001) Wirkung der Temperatur auf kleine Larven von O. sulcatus. Sie zeigten für kleine Larven und Puppen aber auch unterschiedliche Mortlitätsgrade an, die nicht auf Nematoden zurückgingen. Die Anwendung von Abbott's Korrektur zur Prüfung der Mortalität wird kritisch hinterfragt, die Gültigkeit der Theorie der “competing risks” wird geprüft.

Infectivity of populations of the entomopathogenic nematodes Steinernema feltiae and Heterorhabditis megidis in relation to temperature, age and lipid content

Nematology ◽  
2000 ◽  
Vol 2 (5) ◽  
pp. 515-521 ◽  
Author(s):  
Hara Menti ◽  
Denis Wright ◽  
Roland Perry
Keyword(s):  
Lipid Content ◽  
Dose Response ◽  
Entomopathogenic Nematodes ◽  
Galleria Mellonella ◽  
Steinernema Feltiae ◽  
Optimal Temperature ◽  
Temperature Range ◽  
Heterorhabditis Megidis ◽  
Before And After ◽  
The Uk

AbstractThe infectivity of populations of the entomopathogenic nematodes Steinernema feltiae and Heterorhabditis megidis from Greece (GR) and the UK was compared using Galleria mellonella larvae as hosts. Dose-response tests showed that the two Steinernema populations did not differ in their establishment rates but they were more infective than H. megidis UK 211. The temperature range for infectivity was greater than that for development. However, the optimal temperature for infection and development for all populations was 23°C. Infectivity of Steinernema populations was not affected by storage for 12 weeks. However, 12 week-old H. megidis UK 211 infective juveniles (IJ) were less infective than fresh IJ. H. megidis GR showed very low establishment rates at all the doses and temperatures tested, before and after storage. The results are discussed in relation to the nematodes' climatic origin and lipid content. Pouvoir infestant de populations des nématodes entomopathogènes Steinernema feltiae et Heterorhabditis megidis suivant la température, l'âge et le contenu lipidique - Le pouvoir infestant de populations des nématodes entomopathogènes Steinernema feltiae et Heterorhabditis megidis provenant de Grèce et du Royaume Uni a été comparée, utilisant comme hôte Galleria mellonella. Les tests de dose/réaction ont montré que les taux d'établissement des deux populations ne diffèrent pas mais que leur pouvoir infestant était plus élevée que celle de H. megidis UK211. La plage des températures permettant l'infestation était plus étendue que celle relative au développement. Cependant, les températures optimales pour l'infestation et pour le développement étaient l'une et l'autre de 23°C pour toutes les populations. L'infestivité des populations de Steinernema n'a pas été affectée par un stockage de 12 semaines. Les juvéniles infestants de H. megidis UK211 âgés de 12 semaines montraient toutefois une infestivité plus faible que celle d'individus frais. Les specimens de H. megidis provenant de Grèce présentaient - que ce soit avant ou après le stockage - des taux d'établissement très faibles pour toutes les doses et les températures testées. Ces résultats sont discutés en relation avec l'origine climatique et le contenu lipidique des nématodes.

Comparison of metabolites produced in vitro and in vivo by Photorhabdus luminescens, a bacterial symbiont of the entomopathogenic nematode Heterorhabditis megidis

1998 ◽  
Vol 44 (11) ◽  
pp. 1072-1077 ◽  
Author(s):  
Kaiji Hu ◽  
Jianxiong Li ◽  
Wenjie Wang ◽  
Houming Wu ◽  
Hai Lin ◽  
...  
Keyword(s):  
Galleria Mellonella ◽  
Entomopathogenic Nematode ◽  
Culture Broth ◽  
Bacterial Symbiont ◽  
Natural Source ◽  
Photorhabdus Luminescens ◽  
Heterorhabditis Megidis ◽  
Organic Extracts

The types of metabolites produced by Photorhabdus luminescens C9 when it is introduced by Heterorhabditis megidis 90 into Galleria mellonella larvae are different from those produced in tryptic soy broth. Only 3,5-dihydroxy-4-isopropylstilbene 1 was identified from the organic extracts of P. luminescens culture broth, but both 3,5-dihydroxy-4-isopropylstilbene 1 and 3,5-dihydroxy-4-ethylstilbene 3 were isolated from the organic extracts of nematode-bacterium infected G. mellonella larvae. In addition to two pigments, both of which had been previously reported from P. luminescens C9 culture broth, three pigments, 1,8-dihydroxy-3-methoxy-9,10-anthraquinone 2, 1-hydroxy-2,6,8-trimethoxy-9,10-anthraquinone 6, and 1,4-dihydroxy-2,5-dimethoxy-9,10-anthraquinone 7 were isolated from the organic extracts of G. mellonella larvae infected by the nematode-bacterium complex. Among these, compounds 6 and 7 are novel and isolated from a natural source for the first time.Key words: Photorhabdus luminescens, Heterorhabditis megidis, 1-hydroxy-2,6,8-trimethoxy-9,10-anthraquinone, 1,4-dihydroxy-2,5-dimethoxy-9,10-anthraquinone, pigment.

Applicability of Instability Index for In vitro Protein Stability Prediction

2019 ◽  
Vol 26 (5) ◽  
pp. 339-347 ◽  
Author(s):  
Dilani G. Gamage ◽  
Ajith Gunaratne ◽  
Gopal R. Periyannan ◽  
Timothy G. Russell
Keyword(s):  
Protein Stability ◽  
Caulobacter Crescentus ◽  
Effect Of Temperature ◽  
Instability Index ◽  
Dipeptide Composition ◽  
Experimental Conditions ◽  
The Stability ◽  
Vitro Protein

Background: The dipeptide composition-based Instability Index (II) is one of the protein primary structure-dependent methods available for in vivo protein stability predictions. As per this method, proteins with II value below 40 are stable proteins. Intracellular protein stability principles guided the original development of the II method. However, the use of the II method for in vitro protein stability predictions raises questions about the validity of applying the II method under experimental conditions that are different from the in vivo setting. Objective: The aim of this study is to experimentally test the validity of the use of II as an in vitro protein stability predictor. Methods: A representative protein CCM (CCM - Caulobacter crescentus metalloprotein) that rapidly degrades under in vitro conditions was used to probe the dipeptide sequence-dependent degradation properties of CCM by generating CCM mutants to represent stable and unstable II values. A comparative degradation analysis was carried out under in vitro conditions using wildtype CCM, CCM mutants and two other candidate proteins: metallo-β-lactamase L1 and α -S1- casein representing stable, borderline stable/unstable, and unstable proteins as per the II predictions. The effect of temperature and a protein stabilizing agent on CCM degradation was also tested. Results: Data support the dipeptide composition-dependent protein stability/instability in wt-CCM and mutants as predicted by the II method under in vitro conditions. However, the II failed to accurately represent the stability of other tested proteins. Data indicate the influence of protein environmental factors on the autoproteolysis of proteins. Conclusion: Broader application of the II method for the prediction of protein stability under in vitro conditions is questionable as the stability of the protein may be dependent not only on the intrinsic nature of the protein but also on the conditions of the protein milieu.

scholarly journals A Peptide Found in Human Serum, Derived from the C-Terminus of Albumin, Shows Antifungal Activity In Vitro and In Vivo

2020 ◽  
Vol 8 (10) ◽  
pp. 1627
Author(s):  
Tecla Ciociola ◽  
Pier Paolo Zanello ◽  
Tiziana D’Adda ◽  
Serena Galati ◽  
Stefania Conti ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Human Serum ◽  
Fungicidal Activity ◽  
Galleria Mellonella ◽  
Serum Proteins ◽  
Morphological Alterations ◽  
C Terminus ◽  
Different Sources

The growing problem of antimicrobial resistance highlights the need for alternative strategies to combat infections. From this perspective, there is a considerable interest in natural molecules obtained from different sources, which are shown to be active against microorganisms, either alone or in association with conventional drugs. In this paper, peptides with the same sequence of fragments, found in human serum, derived from physiological proteins, were evaluated for their antifungal activity. A 13-residue peptide, representing the 597–609 fragment within the albumin C-terminus, was proved to exert a fungicidal activity in vitro against pathogenic yeasts and a therapeutic effect in vivo in the experimental model of candidal infection in Galleria mellonella. Studies by confocal microscopy and transmission and scanning electron microscopy demonstrated that the peptide penetrates and accumulates in Candida albicans cells, causing gross morphological alterations in cellular structure. These findings add albumin to the group of proteins, which already includes hemoglobin and antibodies, that could give rise to cryptic antimicrobial fragments, and could suggest their role in anti-infective homeostasis. The study of bioactive fragments from serum proteins could open interesting perspectives for the development of new antimicrobial molecules derived by natural sources.

scholarly journals Hexapod Assassins’ Potion: Venom Composition and Bioactivity from the Eurasian Assassin Bug Rhynocoris iracundus

Biomedicines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 819
Author(s):  
Nicolai Rügen ◽  
Timothy P. Jenkins ◽  
Natalie Wielsch ◽  
Heiko Vogel ◽  
Benjamin-Florian Hempel ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Galleria Mellonella ◽  
Systemic Reactions ◽  
Venom Composition ◽  
Assassin Bug ◽  
Molecular Components ◽  
First Time ◽  
Tissue Digestion

Assassin bug venoms are potent and exert diverse biological functions, making them potential biomedical goldmines. Besides feeding functions on arthropods, assassin bugs also use their venom for defense purposes causing localized and systemic reactions in vertebrates. However, assassin bug venoms remain poorly characterized. We collected the venom from the assassin bug Rhynocoris iracundus and investigated its composition and bioactivity in vitro and in vivo. It caused lysis of murine neuroblastoma, hepatoma cells, and healthy murine myoblasts. We demonstrated, for the first time, that assassin bug venom induces neurolysis and suggest that it counteracts paralysis locally via the destruction of neural networks, contributing to tissue digestion. Furthermore, the venom caused paralysis and melanization of Galleria mellonella larvae and pupae, whilst also possessing specific antibacterial activity against Escherichia coli, but not Listeria grayi and Pseudomonas aeruginosa. A combinatorial proteo-transcriptomic approach was performed to identify potential toxins responsible for the observed effects. We identified neurotoxic Ptu1, an inhibitory cystin knot (ICK) toxin homologous to ω-conotoxins from cone snails, cytolytic redulysins homologous to trialysins from hematophagous kissing bugs, and pore-forming hemolysins. Additionally, chitinases and kininogens were found and may be responsible for insecticidal and cytolytic activities. We demonstrate the multifunctionality and complexity of assassin bug venom, which renders its molecular components interesting for potential biomedical applications.

scholarly journals In Silico Predicted Antifungal Peptides: In Vitro and In Vivo Anti-Candida Activity

2021 ◽  
Vol 7 (6) ◽  
pp. 439
Author(s):  
Tecla Ciociola ◽  
Walter Magliani ◽  
Tiziano De Simone ◽  
Thelma A. Pertinhez ◽  
Stefania Conti ◽  
...  
Keyword(s):  
In Silico ◽  
Mammalian Cells ◽  
Galleria Mellonella ◽  
Ex Vivo ◽  
Consensus Sequence ◽  
In Silico Analysis ◽  
Significant Activity ◽  
Synthetic Antibody

It has been previously demonstrated that synthetic antibody-derived peptides could exert a significant activity in vitro, ex vivo, and/or in vivo against microorganisms and viruses, as well as immunomodulatory effects through the activation of immune cells. Based on the sequence of previously described antibody-derived peptides with recognized antifungal activity, an in silico analysis was conducted to identify novel antifungal candidates. The present study analyzed the candidacidal and structural properties of in silico designed peptides (ISDPs) derived by amino acid substitutions of the parent peptide KKVTMTCSAS. ISDPs proved to be more active in vitro than the parent peptide and all proved to be therapeutic in Galleria mellonella candidal infection, without showing toxic effects on mammalian cells. ISDPs were studied by circular dichroism spectroscopy, demonstrating different structural organization. These results allowed to validate a consensus sequence for the parent peptide KKVTMTCSAS that may be useful in the development of novel antimicrobial molecules.

scholarly journals In vivo transcriptome analysis provides insights into host-dependent expression of virulence factors by Yersinia entomophaga MH96, during infection of Galleria mellonella

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Amber R Paulson ◽  
Maureen O’Callaghan ◽  
Xue-Xian Zhang ◽  
Paul B Rainey ◽  
Mark R H Hurst
Keyword(s):  
Galleria Mellonella ◽  
Functional Enrichment ◽  
Natural Environments ◽  
Insecticidal Toxin ◽  
Heat Stable ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Cell Densities

Abstract The function of microbes can be inferred from knowledge of genes specifically expressed in natural environments. Here, we report the in vivo transcriptome of the entomopathogenic bacterium Yersinia entomophaga MH96, captured during initial, septicemic, and pre-cadaveric stages of intrahemocoelic infection in Galleria mellonella. A total of 1285 genes were significantly upregulated by MH96 during infection; 829 genes responded to in vivo conditions during at least one stage of infection, 289 responded during two stages of infection, and 167 transcripts responded throughout all three stages of infection compared to in vitro conditions at equivalent cell densities. Genes upregulated during the earliest infection stage included components of the insecticidal toxin complex Yen-TC (chi1, chi2, and yenC1), genes for rearrangement hotspot element containing protein yenC3, cytolethal distending toxin cdtAB, and vegetative insecticidal toxin vip2. Genes more highly expressed throughout the infection cycle included the putative heat-stable enterotoxin yenT and three adhesins (usher-chaperone fimbria, filamentous hemagglutinin, and an AidA-like secreted adhesin). Clustering and functional enrichment of gene expression data also revealed expression of genes encoding type III and VI secretion system-associated effectors. Together these data provide insight into the pathobiology of MH96 and serve as an important resource supporting efforts to identify novel insecticidal agents.

Exploring Galleria mellonella larval model to evaluate antibacterial efficacy of Cecropin A (1-7)- Melittin against multi-drug resistant enteroaggregative Escherichia coli

2021 ◽  
Author(s):  
Jess Vergis ◽  
S V S Malik ◽  
Richa Pathak ◽  
Manesh Kumar ◽  
Nitin V Kurkure ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Galleria Mellonella ◽  
In Vivo Model ◽  
Drug Resistant ◽  
Physiological Concentration ◽  
Microbial Drug Resistance ◽  
Cecropin A ◽  
Screening And Identification

Abstract High throughput in vivo laboratory models is need for screening and identification of effective therapeutic agents to overcome microbial drug-resistance. This study was undertaken to evaluate in vivo antimicrobial efficacy of short-chain antimicrobial peptide- Cecropin A (1–7)-Melittin (CAMA) against three multi- drug resistant enteroaggregative Escherichia coli (MDR-EAEC) field isolates in a Galleria mellonella larval model. The minimum inhibitory concentration (MIC; 2.0 mg/L) and minimum bactericidal concentration (MBC; 4.0 mg/L) of CAMA were determined by microdilution assay. CAMA was found to be stable at high temperatures, physiological concentration of cationic salts and proteases; safe with sheep erythrocytes, secondary cell lines and commensal lactobacilli at lower MICs; and exhibited membrane permeabilisation. In vitro time-kill assay revealed concentration- and time-dependent clearance of MDR-EAEC in CAMA-treated groups at 30 min. CAMA- treated G. mellonella larvae exhibited an increased survival rate, reduced MDR-EAEC counts, immunomodulatory effect and proved non-toxic which concurred with histopathological findings. CAMA exhibited either an equal or better efficacy than the tested antibiotic control, meropenem. This study highlights the possibility of G. mellonella larvae as an excellent in vivo model for investigating the host-pathogen interaction, including the efficacy of antimicrobials against MDR-EAEC strains.

scholarly journals Designing P. aeruginosa synthetic phages with reduced genomes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Diana P. Pires ◽  
Rodrigo Monteiro ◽  
Dalila Mil-Homens ◽  
Arsénio Fialho ◽  
Timothy K. Lu ◽  
...  
Keyword(s):  
Galleria Mellonella ◽  
Antibacterial Properties ◽  
Genetically Engineered ◽  
In Vivo Studies ◽  
Infection Model ◽  
Promising Therapeutic Approach ◽  
Genes Encoding ◽  
First Time

AbstractIn the era where antibiotic resistance is considered one of the major worldwide concerns, bacteriophages have emerged as a promising therapeutic approach to deal with this problem. Genetically engineered bacteriophages can enable enhanced anti-bacterial functionalities, but require cloning additional genes into the phage genomes, which might be challenging due to the DNA encapsulation capacity of a phage. To tackle this issue, we designed and assembled for the first time synthetic phages with smaller genomes by knocking out up to 48% of the genes encoding hypothetical proteins from the genome of the newly isolated Pseudomonas aeruginosa phage vB_PaeP_PE3. The antibacterial efficacy of the wild-type and the synthetic phages was assessed in vitro as well as in vivo using a Galleria mellonella infection model. Overall, both in vitro and in vivo studies revealed that the knock-outs made in phage genome do not impair the antibacterial properties of the synthetic phages, indicating that this could be a good strategy to clear space from phage genomes in order to enable the introduction of other genes of interest that can potentiate the future treatment of P. aeruginosa infections.

Emergence of ceftazidime/avibactam resistance in KPC-3-producing Klebsiella pneumoniae in vivo

2019 ◽  
Vol 74 (11) ◽  
pp. 3211-3216 ◽  
Author(s):  
Stephan Göttig ◽  
Denia Frank ◽  
Eleonora Mungo ◽  
Anika Nolte ◽  
Michael Hogardt ◽  
...  
Keyword(s):  
Combination Therapy ◽  
Klebsiella Pneumoniae ◽  
Selection Pressure ◽  
Galleria Mellonella ◽  
Phenotypic Characterization ◽  
Infection Model ◽  
Development Of Resistance ◽  
Time Kill

Abstract Objectives The β-lactam/β-lactamase inhibitor combination ceftazidime/avibactam is active against KPC-producing Enterobacterales. Herein, we present molecular and phenotypic characterization of ceftazidime/avibactam resistance in KPC-3-producing Klebsiella pneumoniae that emerged in vivo and in vitro. Methods Sequence analysis of blaKPC-3 was performed from clinical and in vitro-generated ceftazidime/avibactam-resistant K. pneumoniae isolates. Time–kill kinetics and the Galleria mellonella infection model were applied to evaluate the activity of ceftazidime/avibactam and imipenem alone and in combination. Results The ceftazidime/avibactam-resistant clinical K. pneumoniae isolate revealed the amino acid change D179Y in KPC-3. Sixteen novel mutational changes in KPC-3 among in vitro-selected ceftazidime/avibactam-resistant isolates were described. Time–kill kinetics showed the emergence of a resistant subpopulation under selection pressure with either imipenem or ceftazidime/avibactam. However, combined selection pressure with imipenem plus ceftazidime/avibactam prevented the development of resistance and resulted in bactericidal activity. Concordantly, the G. mellonella infection model revealed that monotherapy with ceftazidime/avibactam is prone to select for resistance in vivo and that combination therapy with imipenem results in significantly better survival. Conclusions Ceftazidime/avibactam is a valuable antibiotic against MDR and carbapenem-resistant Enterobacterales. Based on time–kill kinetics as well as an in vivo infection model we postulate a combination therapy of ceftazidime/avibactam and imipenem as a strategy to prevent the development of ceftazidime/avibactam resistance in KPC-producing Enterobacterales in vivo.

Sign in / Sign up

Export Citation Format

Share Document