Publications by authors named "Andreas Vilcinskas"

216 Publications

Genomic analysis of novel Yarrowia-like yeast symbionts associated with the carrion-feeding burying beetle Nicrophorus vespilloides.

BMC Genomics 2021 May 3;22(1):323. Epub 2021 May 3.

Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Ohlebergsweg 12, 35392, Giessen, Germany.

Background: Mutualistic interactions with microbes can help insects adapt to extreme environments and unusual diets. An intriguing example is the burying beetle Nicrophorus vespilloides, which feeds and reproduces on small vertebrate carcasses. Its fungal microbiome is dominated by yeasts that potentially facilitate carcass utilization by producing digestive enzymes, eliminating cadaver-associated toxic volatiles (that would otherwise attract competitors), and releasing antimicrobials to sanitize the microenvironment. Some of these yeasts are closely related to the biotechnologically important species Yarrowia lipolytica.

Results: To investigate the roles of these Yarrowia-like yeast (YLY) strains in more detail, we selected five strains from two different phylogenetic clades for third-generation sequencing and genome analysis. The first clade, represented by strain B02, has a 20-Mb genome containing ~ 6400 predicted protein-coding genes. The second clade, represented by strain C11, has a 25-Mb genome containing ~ 6300 predicted protein-coding genes, and extensive intraspecific variability within the ITS-D1/D2 rDNA region commonly used for species assignments. Phenotypic microarray analysis revealed that both YLY strains were able to utilize a diverse range of carbon and nitrogen sources (including microbial metabolites associated with putrefaction), and can grow in environments with extreme pH and salt concentrations.

Conclusions: The genomic characterization of five yeast strains isolated from N. vespilloides resulted in the identification of strains potentially representing new YLY species. Given their abundance in the beetle hindgut, and dominant growth on beetle-prepared carcasses, the analysis of these strains has revealed the genetic basis of a potential symbiotic relationship between yeasts and burying beetles that facilitates carcass digestion and preservation.
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http://dx.doi.org/10.1186/s12864-021-07597-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8091737PMC
May 2021

Morphological Analysis Reveals a Compartmentalized Duct in the Venom Apparatus of the Wasp Spider ().

Toxins (Basel) 2021 04 9;13(4). Epub 2021 Apr 9.

LOEWE Centre for Translational Biodiversity Genomics (TBG), Senckenberganlage 25, 60325 Frankfurt, Germany.

Spiders are one of the most successful groups of venomous animals, but surprisingly few species have been examined in sufficient detail to determine the structure of their venom systems. To learn more about the venom system of the family Araneidae (orb-weavers), we selected the wasp spider () and examined the general structure and morphology of the venom apparatus by light microscopy. This revealed morphological features broadly similar to those reported in the small number of other spiders subject to similar investigations. However, detailed evaluation of the venom duct revealed the presence of four structurally distinct compartments. We propose that these subunits facilitate the expression and secretion of venom components, as previously reported for similar substructures in pit vipers and cone snails.
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http://dx.doi.org/10.3390/toxins13040270DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8070055PMC
April 2021

The European Map Butterfly as a Model to Study the Molecular Basis and Evolutionary Ecology of Seasonal Polyphenism.

Insects 2021 Apr 6;12(4). Epub 2021 Apr 6.

Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Ohlebergsweg 12, 35392 Giessen, Germany.

The European map butterfly is a well-known example of seasonal polyphenism. Spring and summer imagoes exhibit distinct morphological phenotypes. Key environmental factors responsible for the expression of different morphs are day length and temperature. Larval exposure to light for more than 16 h per day entails direct development and results in the adult f. summer phenotype. Less than 15.5 h per day increasingly promotes diapause and the adult f. spring phenotype. The phenotype depends on the timing of the release of 20-hydroxyecdysone in pupae. Release within the first days after pupation potentially inhibits the default "-gene-expression-profile" because pre-pupae destined for diapause or subitaneous development have unique transcriptomic programs. Moreover, multiple microRNAs and their targets are differentially regulated during the larval and pupal stages, and candidates for diapause maintenance, duration, and phenotype determination have been identified. However, the complete pathway from photoreception to timekeeping and diapause or subitaneous development remains unclear. Beside the wing polyphenism, the hormonal and epigenetic modifications of the two phenotypes also include differences in biomechanical design and immunocompetence. Here, we discuss research on the physiological and molecular basis of polyphenism in , including hormonal control, epigenetic regulation, and the effect of ecological parameters on developmental fate.
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http://dx.doi.org/10.3390/insects12040325DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8067495PMC
April 2021

Cottonseed Press Cake as a Potential Diet for Industrially Farmed Black Soldier Fly Larvae Triggers Adaptations of Their Bacterial and Fungal Gut Microbiota.

Front Microbiol 2021 29;12:634503. Epub 2021 Mar 29.

Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Giessen, Germany.

Black soldier fly larvae (, Diptera: Stratiomyidae) are used for the bioconversion of organic side products into valuable compounds such as proteins, lipids and chitin. However, the economic competitiveness of farmed insects compared to conventional protein production systems in agriculture and aquaculture depends on the availability of large quantities of inexpensive insect feed. Cottonseed press cake (CPC) is a side-stream of cotton production that is rich in proteins and lipids but unsuitable as feed for several farmed animals, except ruminants, due to the presence of the anti-nutritional sesquiterpenoid gossypol. Here, we tested CPC as a feed for black soldier fly larvae and studied the impact of this diet on the gut microbiome. Larvae reared on CPC developed normally and even showed a shorter life-cycle, but were smaller at the end of larval development than control larvae reared on chicken feed. The adaptability of the larvae to different diets is mediated by their versatile gut microbiome, which facilitates digestion and detoxification. We therefore used amplicon sequencing to analyze the bacterial and fungal communities associated with larvae reared on each diet, revealing differences between the larval guts and frass (residual feed substrate) as well as differences between the two diet groups. For example, and Aspergillaceae were significantly enriched in guts of the CPC diet group and may help to metabolize compounds such as gossypol. Potentially probiotic yeasts and beneficial , which presumably belong to the core microbiota, were detected in high relative abundance in the gut and frass, indicating a functional role of these microbes, especially the protection against pathogens. We conclude that CPC may be suitable as an inexpensive and environmentally sustainable feed for the industrial rearing of black soldier flies.
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http://dx.doi.org/10.3389/fmicb.2021.634503DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8039154PMC
March 2021

Tick defensin γ-core reduces Fusarium graminearum growth and abrogates mycotoxins production with high efficiency.

Sci Rep 2021 Apr 12;11(1):7962. Epub 2021 Apr 12.

INRAE, Mycology and Food Safety (MycSA), 33882, Villenave d'Ornon, France.

Fusarium graminearum is a major fungal pathogen affecting crops of worldwide importance. F. graminearum produces type B trichothecene mycotoxins (TCTB), which are not fully eliminated during food and feed processing. Therefore, the best way to minimize TCTB contamination is to develop prevention strategies. Herein we show that treatment with the reduced form of the γ-core of the tick defensin DefMT3, referred to as TickCore3 (TC3), decreases F. graminearum growth and abrogates TCTB production. The oxidized form of TC3 loses antifungal activity, but retains anti-mycotoxin activity. Molecular dynamics show that TC3 is recruited by specific membrane phospholipids in F. graminearum and that membrane binding of the oxidized form of TC3 is unstable. Capping each of the three cysteine residues of TC3 with methyl groups reduces its inhibitory efficacy. Substitutions of the positively-charged residues lysine (Lys) 6 or arginine 7 by threonine had the highest and the lesser impact, respectively, on the anti-mycotoxin activity of TC3. We conclude that the binding of linear TC3 to F. graminearum membrane phospholipids is required for the antifungal activity of the reduced peptide. Besides, Lys6 appears essential for the anti-mycotoxin activity of the reduced peptide. Our results provide foundation for developing novel and environment-friendly strategies for controlling F. graminearum.
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http://dx.doi.org/10.1038/s41598-021-86904-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8042122PMC
April 2021

Tribolium castaneum defensin 1 kills Moraxella catarrhalisin an in vitro infection model but does not harm commensal bacteria.

Virulence 2021 Dec;12(1):1003-1010

Institute for Lung Research, Universities of Giessen and Marburg Lung Center, Philipps-University Marburg, Marburg, Germany.

is a bacterial pathogen that causes respiratory tract infections in humans. The increasing prevalence of antibiotic-resistant strains has created a demand for alternative treatment options. We therefore tested 23 insect antimicrobial peptides (AMPs) for their activity against in a human infection model with primary macrophages, and against commensal bacteria. Effects on bacterial growth were determined by colony counting and growth curve analysis. The inflammatory macrophage response was characterized by qPCR and multiplex ELISA. Eleven of the AMPs were active against . Defensin 1 from the red flour beetle significantly inhibited bacterial growth and reduced the number of colony forming units. This AMP also showed antibacterial activity in the infection model, reducing cytokine expression and release by macrophages. Defensin 1 had no effect on the commensal bacteria and . However, sarcotoxin 1 C from the green bottle fly was active against and , but not against . The ability of defensin 1 to inhibit but not selected commensal bacteria, and the absence of cytotoxic or inflammatory effects against human blood-derived macrophages, suggests this AMP may be suitable for development as a new therapeutic lead against antibiotic-resistant .
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http://dx.doi.org/10.1080/21505594.2021.1908741DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8043168PMC
December 2021

Exposure to low doses of pesticides induces an immune response and the production of nitric oxide in honeybees.

Sci Rep 2021 Mar 25;11(1):6819. Epub 2021 Mar 25.

Fraunhofer Institute for Molecular Biology and Applied Ecology, Ohlebergsweg 12, 35394, Giessen, Germany.

Honeybees are essential pollinators of many agricultural crops and wild plants. However, the number of managed bee colonies has declined in some regions of the world over the last few decades, probably caused by a combination of factors including parasites, pathogens and pesticides. Exposure to these diverse biotic and abiotic stressors is likely to trigger immune responses and stress pathways that affect the health of individual honeybees and hence their contribution to colony survival. We therefore investigated the effects of an orally administered bacterial pathogen (Pseudomonas entomophila) and low-dose xenobiotic pesticides on honeybee survival and intestinal immune responses. We observed stressor-dependent effects on the mean lifespan, along with the induction of genes encoding the antimicrobial peptide abaecin and the detoxification factor cytochrome P450 monooxygenase CYP9E2. The pesticides also triggered the immediate induction of a nitric oxide synthase gene followed by the delayed upregulation of catalase, which was not observed in response to the pathogen. Honeybees therefore appear to produce nitric oxide as a specific defense response when exposed to xenobiotic stimuli. The immunity-related and stress-response genes we tested may provide useful stressor-dependent markers for ecotoxicological assessment in honeybee colonies.
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http://dx.doi.org/10.1038/s41598-021-86293-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7994568PMC
March 2021

Elucidation of the microRNA Transcriptome in Western Corn Rootworm Reveals Its Dynamic and Evolutionary Complexity.

Genomics Proteomics Bioinformatics 2021 Feb 16. Epub 2021 Feb 16.

Corteva Agriscience™, Agriculture Division of DowDuPont™, Indiana, 46268, United States. Electronic address:

Diabrotica virgifera virgifera (western corn rootworm, WCR) is one of the most destructive agricultural insect pests in North America. It is highly adaptive to environmental stimuli and crop protection technologies. However, little is known about the underlying genetic basis of WCR behavior and adaptation. More specifically, the involvement of small RNAs (sRNAs), especially microRNAs (miRNAs), a class of endogenous small non-coding RNAs that regulate various biological processes, has not been examined, and the datasets of putative sRNA sequences have not previously been generated for WCR. To achieve a comprehensive collection of sRNA transcriptomes in WCR, we constructed, sequenced, and analyzed sRNA libraries from different life stages of WCR and northern corn rootworm (NCR), and identified 101 conserved pre-miRNAs in WCR and other Arthropoda. We also identified 277 corn rootworm specific pre-miRNAs. Systematic analyses of sRNA populations in WCR revealed that its sRNA transcriptome, which includes piwi-interacting RNAs (piRNAs) and miRNAs, undergoes a dynamic change throughout insect development. Phylogenetic analysis of miRNA datasets from model species reveals that a large pool of species-specific miRNAs exists in corn rootworm; these are potentially evolutionarily transient. Comparisons of WCR miRNA clusters to other insect species highlight conserved miRNA-regulated processes that are common to insects. Parallel Analysis of RNA Ends (PARE) also uncovered potential miRNA-guided cleavage sites in WCR. Overall, this study provides a new resource for studying the sRNA transcriptome and miRNA-mediated gene regulation in WCR and other Coleopteran insects.
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http://dx.doi.org/10.1016/j.gpb.2019.03.008DOI Listing
February 2021

gen. nov., sp. nov., a new member of the isolated from the gut of the cockroach .

Int J Syst Evol Microbiol 2019 Jun 2;71(3). Epub 2021 Feb 2.

Institute for Insect Biotechnology, Justus-Liebig-University of Giessen, Giessen, Germany.

A novel bacterium designated G55GP and pertaining to the family was isolated from the gut of the Madagascar hissing cockroach . The Gram-negative cells were rod-shaped and non-motile. The complete 16S rRNA sequence of the strain G55GP showed the highest pairwise similarity to CFN-Cf-55T (95.35 %), suggesting it represents a potential new genus of the family . Phylogenetic analysis based on 16S rRNA gene and 106 orthologous housekeeping protein sequences revealed that G55GP forms a monophyletic clade with the genus , which thus far has also been isolated exclusively from insects. The G55GP genome size was 2.70 Mbp, and the G+C content was 45.4 mol%, which is lower than most acetic acid bacteria (51-68 mol%) but comparable to AH83 (45.1 mol%) and higher than A911 (36.8 mol%). Overall genome relatedness indices based on gene and protein sequences strongly supported the assignment of G55GP to a new genus within the family . The percentage of conserved proteins, which is a useful metric for genus differentiation, was below 54 % when comparing G55GP to type strains of acetic acid bacteria, thus strongly supporting our hypothesis that G55GP is a member of a yet-undescribed genus. The fatty acid composition of G55GP differed from that of closely related acetic acid bacteria, particularly given the presence of C9/11 and the absence of C and C 2-OH fatty acids. Strain G55GP also differed in terms of metabolic features such as its ability to produce acid from d-mannitol, and its inability to produce acetic acid from ethanol or to oxidize glycerol to dihydroxyacetone. Based on the results of combined genomic, phenotypic and phylogenetic characterizations, isolate G55GP (=LMG 31394=DSM 111244) is considered to represent a new species in a new genus, for which we propose the name gen. nov., sp. nov.
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http://dx.doi.org/10.1099/ijsem.0.004666DOI Listing
June 2019

Honeybee colonies compensate for pesticide-induced effects on royal jelly composition and brood survival with increased brood production.

Sci Rep 2021 Jan 8;11(1):62. Epub 2021 Jan 8.

LLH Bee Institute, Erlenstr. 9, 35274, Kirchhain, Germany.

Sublethal doses of pesticides affect individual honeybees, but colony-level effects are less well understood and it is unclear how the two levels integrate. We studied the effect of the neonicotinoid pesticide clothianidin at field realistic concentrations on small colonies. We found that exposure to clothianidin affected worker jelly production of individual workers and created a strong dose-dependent increase in mortality of individual larvae, but strikingly the population size of capped brood remained stable. Thus, hives exhibited short-term resilience. Using a demographic matrix model, we found that the basis of resilience in dosed colonies was a substantive increase in brood initiation rate to compensate for increased brood mortality. However, computer simulation of full size colonies revealed that the increase in brood initiation led to severe reductions in colony reproduction (swarming) and long-term survival. This experiment reveals social regulatory mechanisms on colony-level that enable honeybees to partly compensate for effects on individual level.
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http://dx.doi.org/10.1038/s41598-020-79660-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7794607PMC
January 2021

High-Throughput Cultivation for the Selective Isolation of Acidobacteria From Termite Nests.

Front Microbiol 2020 6;11:597628. Epub 2020 Nov 6.

Branch for Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Giessen, Germany.

Microbial communities in the immediate environment of socialized invertebrates can help to suppress pathogens, in part by synthesizing bioactive natural products. Here we characterized the core microbiomes of three termite species (genus ) and their nest material to gain more insight into the diversity of termite-associated bacteria. Sampling a healthy termite colony over time implicated a consolidated and highly stable microbiome, pointing toward the fact that beneficial bacterial phyla play a major role in termite fitness. In contrast, there was a significant shift in the composition of the core microbiome in one nest during a fungal infection, affecting the abundance of well-characterized species (phylum Actinobacteria) as well as less-studied bacterial phyla such as Acidobacteria. High-throughput cultivation in microplates was implemented to isolate and identify these less-studied bacterial phylogenetic group. Amplicon sequencing confirmed that our method maintained the bacterial diversity of the environmental samples, enabling the isolation of novel Acidobacteriaceae and expanding the list of cultivated species to include two strains that may define new species within the genera and .
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http://dx.doi.org/10.3389/fmicb.2020.597628DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7677567PMC
November 2020

Bacteria associated with cockroaches: health risk or biotechnological opportunity?

Appl Microbiol Biotechnol 2020 Dec 31;104(24):10369-10387. Epub 2020 Oct 31.

Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Ohlebergsweg 12, 35392, Giessen, Germany.

Cockroaches have existed for 300 million years and more than 4600 extant species have been described. Throughout their evolution, cockroaches have been associated with bacteria, and today Blattabacterium species flourish within specialized bacteriocytes, recycling nitrogen from host waste products. Cockroaches can disseminate potentially pathogenic bacteria via feces and other deposits, particularly members of the family Enterobacteriaceae, but also Staphylococcus and Mycobacterium species, and thus, they should be cleared from sites where hygiene is essential, such as hospitals and kitchens. On the other hand, cockroaches also carry bacteria that may produce metabolites or proteins with potential industrial applications. For example, an antibiotic-producing Streptomyces strain was isolated from the gut of the American cockroach Periplaneta americana. Other cockroach-associated bacteria, including but not limited to Bacillus, Enterococcus, and Pseudomonas species, can also produce bioactive metabolites that may be suitable for development as pharmaceuticals or plant protection products. Enzymes that degrade industrially relevant substrates, or that convert biomasses into useful chemical precursors, are also expressed in cockroach-derived bacteria and could be deployed for use in the food/feed, paper, oil, or cosmetics industries. The analysis of cockroach gut microbiomes has revealed a number of lesser-studied bacteria that may form the basis of novel taxonomic groups. Bacteria associated with cockroaches can therefore be dangerous or useful, and this review explores the bacterial clades that may provide opportunities for biotechnological exploitation. KEY POINTS: • Members of the Enterobacteriaceae are the most frequently cultivated bacteria from cockroaches. • Cultivation-independent studies have revealed a diverse community, led by the phyla Bacteroidetes and Firmicutes. • Although cockroaches may carry pathogenic bacteria, most strains are innocuous and may be useful for biotechnological applications. Graphical abstract.
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http://dx.doi.org/10.1007/s00253-020-10973-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7671988PMC
December 2020

Anthelminthic Activity of Assassin Bug Venom against the Blood Fluke .

Antibiotics (Basel) 2020 Oct 1;9(10). Epub 2020 Oct 1.

Institute of Parasitology, BFS, Justus Liebig University of Giessen, Schubertstr. 81, 35392 Giessen, Germany.

Helminths such as the blood fluke represent a major global health challenge due to limited availability of drugs. Most anthelminthic drug candidates are derived from plants, whereas insect-derived compounds have received little attention. This includes venom from assassin bugs, which contains numerous bioactive compounds. Here, we investigated whether venom from the European predatory assassin bug has antischistosomal activity. Venom concentrations of 10-50 µg/mL inhibited the motility and pairing of adult worms in vitro and their capacity to produce eggs. We used EdU-proliferation assays to measure the effect of venom against parasite stem cells, which are essential for survival and reproduction. We found that venom depleted proliferating stem cells in different tissues of the male parasite, including neoblasts in the parenchyma and gonadal stem cells. Certain insect venoms are known to lyse eukaryotic cells, thus limiting their therapeutic potential. We therefore carried out hemolytic activity assays using porcine red blood cells, revealing that the venom had no significant effect at a concentration of 43 µg/mL. The observed anthelminthic activity and absence of hemolytic side effects suggest that the components of venom should be investigated in more detail as potential antischistosomal leads.
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http://dx.doi.org/10.3390/antibiotics9100664DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7599792PMC
October 2020

Context-dependent venom deployment and protein composition in two assassin bugs.

Ecol Evol 2020 Sep 17;10(18):9932-9947. Epub 2020 Aug 17.

Department of Entomology Max Planck Institute for Chemical Ecology Jena Germany.

The Heteroptera are a diverse suborder of phytophagous, hematophagous, and zoophagous insects. The shift to zoophagy can be traced back to the transformation of salivary glands into venom glands, but the venom is used not only to kill and digest invertebrate prey but also as a defense strategy, mainly against vertebrates. In this study, we used an integrated transcriptomics and proteomics approach to compare the composition of venoms from the anterior main gland (AMG) and posterior main gland (PMG) of the reduviid bugs L. and Stål. In both species, the AMG and PMG secreted distinct protein mixtures with few interspecific differences. PMG venom consisted mostly of S1 proteases, redulysins, Ptu1-like peptides, and uncharacterized proteins, whereas AMG venom contained hemolysins and cystatins. There was a remarkable difference in biological activity between the AMG and PMG venoms, with only PMG venom conferring digestive, neurotoxic, hemolytic, antibacterial, and cytotoxic effects. Proteomic analysis of venom samples revealed the context-dependent use of AMG and PMG venom. Although both species secreted PMG venom alone to overwhelm their prey and facilitate digestion, the deployment of defensive venom was species-dependent. almost exclusively used PMG venom for defense, whereas secreted PMG venom in response to mild harassment but AMG venom in response to more intense harassment. This intriguing context-dependent use of defensive venom indicates that future research should focus on species-dependent differences in venom composition and defense strategies among predatory Heteroptera.
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http://dx.doi.org/10.1002/ece3.6652DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7520181PMC
September 2020

Larvae of the Clothing Moth Maintain Gut Bacteria that Secrete Enzyme Cocktails to Facilitate the Digestion of Keratin.

Microorganisms 2020 Sep 14;8(9). Epub 2020 Sep 14.

Entomology Department, Max-Planck Institute for Chemical Ecology, Hans-Knoell-Strasse 8, 07745 Jena, Germany.

The evolutionary success of insects is promoted by their association with beneficial microbes that enable the utilization of unusual diets. The synanthropic clothing moth provides an intriguing example of this phenomenon. The caterpillars of this species have adapted to feed on keratin-rich diets such as feathers and wool, which cannot be digested by most other animals and are resistant to common digestive enzymes. Inspired by the hypothesis that this ability may be conferred by symbiotic microbes, we utilized a simple assay to detect keratinase activity and a method to screen gut bacteria for candidate enzymes, which were isolated from feather-fed larvae. The isolation of DNA from keratin-degrading bacterial strains followed by de novo genome sequencing resulted in the identification of a novel bacterial strain related to sp. FDAARGOS_235. Genome annotation identified 20 genes with keratinase domains. Proteomic analysis of the culture supernatant from this gut bacterium grown in non-nutrient buffer supplemented with feathers revealed several candidate enzymes potentially responsible for keratin degradation, including a thiol-disulfide oxidoreductase and multiple proteases. Our results suggest that the unusual diet of larvae promotes their association with keratinolytic microorganisms and that the ability of larvae to feed on keratin can at least partially be attributed to bacteria that produce a cocktail of keratin-degrading enzymes.
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http://dx.doi.org/10.3390/microorganisms8091415DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7563610PMC
September 2020

Molecular Networking-Guided Discovery and Characterization of Stechlisins, a Group of Cyclic Lipopeptides from a sp.

J Nat Prod 2020 09 21;83(9):2607-2617. Epub 2020 Aug 21.

Branch for Bioresources of the Fraunhofer Institute for Molecular Biology and Applied Ecology, 35394 Giessen, Germany.

Increasingly sensitive analytical instruments and robust downstream data processing tools have revolutionized natural product research over the past decade. A molecular networking-guided survey led to the identification of 33 new cyclic lipopeptides (CLPs) from the culture broth of the proteobacterium sp. FhG100052. The compound family resembles members of the amphisin group of CLPs that possess a 3-hydroxy fatty acid linked to the N-terminus of an undecapeptide core. Culture optimization led to the isolation and subsequent structure elucidation of one known and five new derivatives by extensive MS/MS and NMR experiments in combination with Marfey's analysis. The data were in agreement with analysis of the corresponding biosynthetic gene cluster. Most strikingly, the length of the incorporated fatty acid defined the growth inhibitory effects against FH6810, as observed by MIC values ranging from no inhibition (>128 μg/mL) to 4 μg/mL.
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http://dx.doi.org/10.1021/acs.jnatprod.0c00263DOI Listing
September 2020

Proteo-Transcriptomic Analysis Identifies Potential Novel Toxins Secreted by the Predatory, Prey-Piercing Ribbon Worm .

Mar Drugs 2020 Aug 1;18(8). Epub 2020 Aug 1.

LOEWE Centre for Translational Biodiversity Genomics (LOEWE-TBG), Senckenberganlage 25, 60325 Frankfurt, Germany.

Nemerteans (ribbon worms) employ toxins to subdue their prey, but research thus far has focused on the small-molecule components of mucus secretions and few protein toxins have been characterized. We carried out a preliminary proteotranscriptomic analysis of putative toxins produced by the hoplonemertean (Hoplonemertea, Amphiporidae). No variants were found of known nemertean-specific toxin proteins (neurotoxins, cytotoxins, parbolysins or nemertides) but several toxin-like transcripts were discovered, expressed strongly in the proboscis, including putative metalloproteinases and sequences resembling sea anemone actitoxins, crown-of-thorn sea star plancitoxins, and multiple classes of inhibitor cystine knot/knottin family proteins. Some of these products were also directly identified in the mucus proteome, supporting their preliminary identification as secreted toxin components. Two new nemertean-typical toxin candidates could be described and were named U-nemertotoxin-1 and U-nemertotoxin-2. Our findings provide insight into the largely overlooked venom system of nemerteans and support a hypothesis in which the nemertean proboscis evolved in several steps from a flesh-melting organ in scavenging nemerteans to a flesh-melting and toxin-secreting venom apparatus in hunting hoplonemerteans.
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http://dx.doi.org/10.3390/md18080407DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7460313PMC
August 2020

Defense of Milkweed Bugs (Heteroptera: Lygaeinae) against Predatory Lacewing Larvae Depends on Structural Differences of Sequestered Cardenolides.

Insects 2020 Jul 31;11(8). Epub 2020 Jul 31.

Institute of Phytomedicine, University of Hohenheim, 70599 Stuttgart, Germany.

Predators and parasitoids regulate insect populations and select defense mechanisms such as the sequestration of plant toxins. Sequestration is common among herbivorous insects, yet how the structural variation of plant toxins affects defenses against predators remains largely unknown. The palearctic milkweed bug (Heteroptera: Lygaeinae) was recently shown to sequester cardenolides from (Ranunculaceae), while its relative also obtains cardenolides but from (Plantaginaceae). Remarkably, toxin sequestration protects both species against insectivorous birds, but only gains protection against predatory lacewing larvae. Here, we used a full factorial design to test whether this difference was mediated by the differences in plant chemistry or by the insect species. We raised both species of milkweed bugs on seeds from both species of host plants and carried out predation assays using the larvae of the lacewing . In addition, we analyzed the toxins sequestered by the bugs via liquid chromatography (HPLC). We found that both insect species gained protection by sequestering cardenolides from but not from . Since the total amount of toxins stored was not different between the plant species in and even lower in from compared to , the effect is most likely mediated by structural differences of the sequestered toxins. Our findings indicate that predator-prey interactions are highly context-specific and that the host plant choice can affect the levels of protection to various predator types based on structural differences within the same class of chemical compounds.
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http://dx.doi.org/10.3390/insects11080485DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7469174PMC
July 2020

The Gram-Positive Bacterium Shows Insecticidal Activity against Drosophilid and Aphid Pests.

Insects 2020 Jul 25;11(8). Epub 2020 Jul 25.

Fraunhofer Institute for Molecular Biology and Applied Ecology, Ohlebergsweg 12, D-35394 Giessen, Germany.

Insect pests reduce global crop yields by up to 20%, but the most effective control measures are currently based on environmentally hazardous chemical pesticides. An alternative, ecologically beneficial pest-management strategy involves the use of microbial pathogens (or active compounds and extracts derived from them) that naturally target selected insect pests. A novel strain of the bacterium showed promising activity in our preliminary tests. Here, we investigated its effects in more detail, focusing on drosophilid and aphid pests by testing the survival of two species representing the family Drosophilidae ( and ) and one representing the family Aphididae (). We used oral and septic infection models to administer living bacteria or cell-free extracts to adult flies and aphid nymphs. We found that infection with living bacteria significantly reduced the survival of our insect models, whereas the administration of cell-free extracts had a significant effect only in aphids. These results confirm that has potential as a new biocontrol agent for sustainable pest management.
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http://dx.doi.org/10.3390/insects11080471DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7469177PMC
July 2020

The gut and feed residue microbiota changing during the rearing of Hermetia illucens larvae.

Antonie Van Leeuwenhoek 2020 Sep 7;113(9):1323-1344. Epub 2020 Jul 7.

Institute of Applied Microbiology, Justus-Liebig University Giessen, IFZ-Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.

Larvae of Hermetia illucens, commonly known as black soldier fly, efficiently convert organic waste into nutrient-rich supplements for different applications. Here we performed a preliminary experiment to investigate the dynamics of the H. illucens gut microbiota and changes in the composition of the bacterial community in the residue of the larval feed during rearing. We furthermore quantified the presence of antibiotic resistance and disinfectant genes in the gut and feed microbiota during the rearing process to elucidate if rearing leads to a reduction, increase, and/or transfer of resistance genes from the feed to larvae and vice versa. We found that the gut and feed residue bacterial communities were distinct throughout the rearing process. The gut microbiome remained more stable compared to the feed residue microbiome varying in both bacterial abundance and community structure during rearing. Antibiotic-resistance genes were present in both, gut and feed residues, with a significant increase in pupae and residue samples taken at the end of the rearing process. Disinfectant-resistance genes were present in the feed residue and even increased during the rearing process but were not transferred to the gut microbiome. We conclude that H. illucens larvae have a stable gut microbiome that does not change significantly over the course of larval development, whereas bacterial communities in the feed residue are strongly affected by rearing. If the presence of antibiotics and disinfectants during rearing, can promote the spread of antibiotic/disinfectant-resistance genes among feed and larvae needs to be evaluated in further experiments.
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http://dx.doi.org/10.1007/s10482-020-01443-0DOI Listing
September 2020

An Economic Dilemma Between Molecular Weapon Systems May Explain an Arachno-atypical Venom in Wasp Spiders ().

Biomolecules 2020 06 30;10(7). Epub 2020 Jun 30.

LOEWE Centre for Translational Biodiversity Genomics (LOEWE-TBG), Senckenberganlage 25, 60325 Frankfurt, Germany.

Spiders use venom to subdue their prey, but little is known about the diversity of venoms in different spider families. Given the limited data available for orb-weaver spiders (Araneidae), we selected the wasp spider for detailed analysis. Our strategy combined a transcriptomics pipeline based on multiple assemblies with a dual proteomics workflow involving parallel mass spectrometry techniques and electrophoretic profiling. We found that the remarkably simple venom of has an atypical composition compared to other spider venoms, prominently featuring members of the cysteine-rich secretory protein, antigen 5 and pathogenesis-related protein 1 (CAP) superfamily and other, mostly high-molecular-weight proteins. We also detected a subset of potentially novel toxins similar to neuropeptides. We discuss the potential function of these proteins in the context of the unique hunting behavior of wasp spiders, which rely mostly on silk to trap their prey. We propose that the simplicity of the venom evolved to solve an economic dilemma between two competing yet metabolically expensive weapon systems. This study emphasizes the importance of cutting-edge methods to encompass the lineages of smaller venomous species that have yet to be characterized in detail, allowing us to understand the biology of their venom systems and to mine this prolific resource for translational research.
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http://dx.doi.org/10.3390/biom10070978DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7407881PMC
June 2020

Reprograming of epigenetic mechanisms controlling host insect immunity and development in response to egg-laying by a parasitoid wasp.

Proc Biol Sci 2020 06 10;287(1928):20200704. Epub 2020 Jun 10.

Branch of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Ohlebergsweg 12, 35392 Giessen, Germany.

Parasitoids are insects that use other insects as hosts. They sabotage host cellular and humoral defences to promote the survival of their offspring by injecting viruses and venoms along with their eggs. Many pathogens and parasites disrupt host epigenetic mechanisms to overcome immune system defences, and we hypothesized that parasitoids may use the same strategy. We used the ichneumon wasp as a model idiobiont parasitoid to test this hypothesis, with pupae of the greater wax moth as the host. We found that parasitoid infestation involves the suppression of host immunity-related effector genes and the modulation of host genes involved in developmental hormone signalling. The transcriptional reprogramming of host genes following the injection of parasitoid eggs was associated with changes in host epigenetic mechanisms. The introduction of parasitoids resulted in a transient decrease in host global DNA methylation and the modulation of acetylation ratios for specific histones. Genes encoding regulators of histone acetylation and deacetylation were mostly downregulated in the parasitized pupae, suggesting that parasitoids can suppress host transcription. We also detected a strong parasitoid-specific effect on host microRNAs regulating gene expression at the post-transcriptional level. Our data therefore support the hypothesis that parasitoids may favour the survival of their offspring by interfering with host epigenetic mechanisms to suppress the immune system and disrupt development.
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http://dx.doi.org/10.1098/rspb.2020.0704DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7341927PMC
June 2020

ABC Transporter DerAB of Lactobacillus casei Mediates Resistance against Insect-Derived Defensins.

Appl Environ Microbiol 2020 07 2;86(14). Epub 2020 Jul 2.

Institut für Mikrobiologie, Technische Universität Dresden, Dresden, Germany

Bce-like systems mediate resistance against antimicrobial peptides in bacteria. BL23 encodes an "orphan" ABC transporter that, based on homology to BceAB-like systems, was proposed to contribute to antimicrobial peptide resistance. A mutant lacking the permease subunit was tested for sensitivity against a collection of peptides derived from bacteria, fungi, insects, and humans. Our results show that the transporter specifically conferred resistance against insect-derived cysteine-stabilized αβ defensins, and it was therefore renamed DerAB for fensin esistance ABC transporter. Surprisingly, cells lacking DerAB showed a marked increase in resistance against the lantibiotic nisin. This could be explained by significantly increased expression of the antimicrobial peptide resistance determinants regulated by the Bce-like systems PsdRSAB (formerly module 09) and ApsRSAB (formerly module 12). Bacterial two-hybrid studies in showed that DerB could interact with proteins of the sensory complex in the Psd resistance system. We therefore propose that interaction of DerAB with this complex in the cell creates signaling interference and reduces the cell's potential to mount an effective nisin resistance response. In the absence of DerB, this negative interference is relieved, leading to the observed hyperactivation of the Psd module and thus increased resistance to nisin. Our results unravel the function of a previously uncharacterized Bce-like orphan resistance transporter with pleiotropic biological effects on the cell. Antimicrobial peptides (AMPs) play an important role in suppressing the growth of microorganisms. They can be produced by bacteria themselves-to inhibit competitors-but are also widely distributed in higher eukaryotes, including insects and mammals, where they form an important component of innate immunity. In low-GC-content Gram-positive bacteria, BceAB-like transporters play a crucial role in AMP resistance but have so far been primarily associated with interbacterial competition. Here, we show that the orphan transporter DerAB from the lactic acid bacterium is crucial for high-level resistance against insect-derived AMPs. It therefore represents an important mechanism for interkingdom defense. Furthermore, our results support a signaling interference from DerAB on the PsdRSAB module that might prevent the activation of a full nisin response. The Bce modules from BL23 illustrate a biological paradox in which the intrinsic nisin detoxification potential only arises in the absence of a defensin-specific ABC transporter.
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http://dx.doi.org/10.1128/AEM.00818-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7357469PMC
July 2020

Proline-Rich Antimicrobial Peptides in Medicinal Maggots of Interact With Bacterial DnaK But Do Not Inhibit Protein Synthesis.

Front Pharmacol 2020 24;11:532. Epub 2020 Apr 24.

Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Giessen, Germany.

In the search for new antibiotics to combat multidrug-resistant microbes, insects offer a rich source of novel anti-infectives, including a remarkably diverse array of antimicrobial peptides (AMPs) with broad activity against a wide range of species. Larvae of the common green bottle fly are used for maggot debridement therapy, and their effectiveness in part reflects the large panel of AMPs they secrete into the wound. To investigate the activity of these peptides in more detail, we selected two structurally different proline rich peptides (Lser-PRP2 and Lser-PRP3) in addition to the α-helical peptide Lser-stomoxyn. We investigated the mechanism of anti- action of the PRPs and found that neither of them interfered with protein synthesis but both were able to bind the bacterial chaperone DnaK and are therefore likely to inhibit protein folding. However, unlike Lser-stomoxyn that permeabilized the bacterial membrane by 1% at the low concentration (0.25 µM) neither of the PRPs alone was able to permeabilize membrane. In the presence of this Lser-stomoxyn concentration significant increase in anti- activity of Lser-PRP2 was observed, indicating that this peptide needs specific membrane permeabilizing agents to exert its antibacterial activity. We then examined the AMPs-treated bacterial surface and observed detrimental structural changes in the bacterial cell envelope in response to combined AMPs. The functional analysis of insect AMPs will help select optimal combinations for targeted antimicrobial therapy.
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http://dx.doi.org/10.3389/fphar.2020.00532DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7194015PMC
April 2020

Lysine Acetyltransferase p300/CBP Plays an Important Role in Reproduction, Embryogenesis and Longevity of the Pea Aphid .

Insects 2020 Apr 26;11(5). Epub 2020 Apr 26.

Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for Bioresources, Ohlebergsweg 12, 35392 Giessen, Germany.

CREB-binding protein (p300/CBP) is a universal transcriptional co-regulator with lysine acetyltransferase activity. p300/CBP is a well-known regulator of embryogenesis, and recent studies in beetles and cockroaches have revealed the importance of this protein during post-embryonic development and endocrine signaling. In pest insects, p300/CBP may therefore offer a useful target for control methods based on RNA interference (RNAi). We investigated the role of p300/CBP in the pea aphid (), a notorious pest insect used as a laboratory model for the analysis of complex life-history traits. The RNAi-based attenuation of p300/CBP significantly reduced the aphid lifespan and number of offspring, as well as shortening the reproductive phase, suggesting the manipulation of this gene contributes to accelerated senescence. Furthermore, injection of p300/CBP dsRNA also reduced the number of viable offspring and increased the number of premature nymphs, which developed in abnormally structured ovaries. Our data confirm the evolutionarily conserved function of p300/CBP during insect embryogenesis and show that the protein has a critical effect on longevity, reproduction and development in . The potent effect of p300/CBP silencing indicates that this regulatory protein is an ideal target for RNAi-based aphid control.
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http://dx.doi.org/10.3390/insects11050265DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7290403PMC
April 2020

European Medicinal Leeches-New Roles in Modern Medicine.

Biomedicines 2020 Apr 27;8(5). Epub 2020 Apr 27.

Institute for Insect Biotechnology, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany.

Before the advent of modern medicine, natural resources were widely used by indigenous populations for the prevention and treatment of diseases. The associated knowledge, collectively described as folk medicine or traditional medicine, was largely based on trial-and-error testing of plant extracts (herbal remedies) and the use of invertebrates, particularly medicinal maggots of the blowfly and blood-sucking leeches. The widespread use of traditional medicine in the West declined as scientific advances allowed reproducible testing under controlled conditions and gave rise to the modern fields of biomedical research and pharmacology. However, many drugs are still derived from natural resources, and interest in traditional medicine has been renewed by the ability of researchers to investigate the medical potential of diverse species by high-throughput screening. Likewise, researchers are starting to look again at the benefits of maggot and leech therapy, based on the hypothesis that the use of such animals in traditional medicine is likely to reflect the presence of specific bioactive molecules that can be developed as drug leads. In this review, we consider the modern medical benefits of European medicinal leeches based on the systematic screening of their salivary proteins.
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http://dx.doi.org/10.3390/biomedicines8050099DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7277884PMC
April 2020

Identification of entomopathogenic bacteria associated with the invasive pest Drosophila suzukii in infested areas of Germany.

J Invertebr Pathol 2020 06 27;173:107389. Epub 2020 Apr 27.

Fraunhofer Institute for Molecular Biology and Applied Ecology, Winchester Strasse 2, D-35394 Giessen, Germany; Institute for Insect Biotechnology, Justus Liebig University of Giessen, Heinrich Buff Ring 26-32, D-35392, Germany. Electronic address:

The invasive insect pest Drosophila suzukii causes extensive damage to soft-skinned fruit crops as they ripen. Current control methods involve the application of chemical pesticides, but this approach is ineffective and environmentally hazardous. To investigate the potential of bacterial pathogens carried by D. suzukii as biocontrol agents, we characterized bacteria associated with D. suzukii larvae in two parts of Hesse, Germany, by collecting infested fruits and culturing individual bacteria from moribund specimens for taxonomic classification by 16S rDNA sequencing. Among the bacteria we detected, some had a detrimental effect on the host whereas others were neutral or beneficial. When the detrimental and beneficial bacteria were presented simultaneously, we observed complex tripartite interactions that modulated the insect's innate immune response. Our study provides insight into the complex relationships within the microbiome and pathobiome of D. suzukii and may lead to the isolation of bacteria that can be used as biological control agents.
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http://dx.doi.org/10.1016/j.jip.2020.107389DOI Listing
June 2020

Antimicrobial Peptides from Rat-Tailed Maggots of the Drone Fly Show Potent Activity against Multidrug-Resistant Gram-Negative Bacteria.

Microorganisms 2020 Apr 25;8(5). Epub 2020 Apr 25.

Fraunhofer Institute for Molecular Biology and Applied Ecology, Department of Bioresources, Ohlebergsweg 12, 35392 Giessen, Germany.

The spread of multidrug-resistant Gram-negative bacteria is an increasing threat to human health, because novel compound classes for the development of antibiotics have not been discovered for decades. Antimicrobial peptides (AMPs) may provide a much-needed breakthrough because these immunity-related defense molecules protect many eukaryotes against Gram-negative pathogens. Recent concepts in evolutionary immunology predict the presence of potent AMPs in insects that have adapted to survive in habitats with extreme microbial contamination. For example, the saprophagous and coprophagous maggots of the drone fly (Diptera) can flourish in polluted aquatic habitats, such as sewage tanks and farmyard liquid manure storage pits. We used next-generation sequencing to screen the immunity-related transcriptome for AMPs that are synthesized in response to the injection of bacterial lipopolysaccharide. We identified 22 AMPs and selected nine for larger-scale synthesis to test their activity against a broad spectrum of pathogens, including multidrug-resistant Gram-negative bacteria. Two cecropin-like peptides (EtCec1-a and EtCec2-a) and a diptericin-like peptide (EtDip) displayed strong activity against the pathogens, even under simulated physiological conditions, and also achieved a good therapeutic window. Therefore, these AMPs could be used as leads for the development of novel antibiotics.
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http://dx.doi.org/10.3390/microorganisms8050626DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7284870PMC
April 2020

MicroRNAs regulate innate immunity against uropathogenic and commensal-like Escherichia coli infections in the surrogate insect model Galleria mellonella.

Sci Rep 2020 02 13;10(1):2570. Epub 2020 Feb 13.

Institute for Insect Biotechnology, Justus Liebig University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.

Uropathogenic Escherichia coli (UPEC) strains cause symptomatic urinary tract infections in humans whereas commensal-like E. coli strains in the urinary bladder cause long-term asymptomatic bacteriuria (ABU). We previously reported that UPEC and ABU strains differentially regulate key DNA methylation and histone acetylation components in the surrogate insect host Galleria mellonella to epigenetically modulate innate immunity-related gene expression, which in turn controls bacterial growth. In this follow-up study, we infected G. mellonella larvae with UPEC strain CFT073 or ABU strain 83972 to identify differences in the expression of microRNAs (miRNAs), a class of non-coding RNAs that regulate gene expression at the post-transcriptional level. Our small RNA sequencing analysis showed that UPEC and ABU infections caused significant changes in the abundance of miRNAs in the larvae, and highlighted the differential expression of 147 conserved miRNAs and 95 novel miRNA candidates. We annotated the G. mellonella genome sequence to investigate the miRNA-regulated expression of genes encoding antimicrobial peptides, signaling proteins, and enzymatic regulators of DNA methylation and histone acetylation in infected larvae. Our results indicate that miRNAs play a role in the epigenetic reprograming of innate immunity in G. mellonella larvae to distinguish between pathogenic and commensal strains of E. coli.
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http://dx.doi.org/10.1038/s41598-020-59407-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7018962PMC
February 2020

The insect antimicrobial peptide cecropin A disrupts uropathogenic Escherichia coli biofilms.

NPJ Biofilms Microbiomes 2020 02 12;6(1). Epub 2020 Feb 12.

Fraunhofer Institute for Molecular Biology and Applied Ecology, Department of Bioresources, 35394, Giessen, Germany.

Current antibiotics cannot eradicate uropathogenic Escherichia coli (UPEC) biofilms, leading to recurrent urinary tract infections. Here, we show that the insect antimicrobial peptide cecropin A (CecA) can destroy planktonic and sessile biofilm-forming UPEC cells, either alone or when combined with the antibiotic nalidixic acid (NAL), synergistically clearing infection in vivo without off-target cytotoxicity. The multi-target mechanism of action involves outer membrane permeabilization followed by biofilm disruption triggered by the inhibition of efflux pump activity and interactions with extracellular and intracellular nucleic acids. These diverse targets ensure that resistance to the CecA + NAL combination emerges slowly. The antimicrobial mechanisms of CecA, thus, extend beyond pore-forming activity to include an unanticipated biofilm-eradication process, offering an alternative approach to combat antibiotic-resistant UPEC infections.
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http://dx.doi.org/10.1038/s41522-020-0116-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7016129PMC
February 2020