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Insects Nov 2021The European grapevine moth (EGVM) (Lepidoptera: Tortricidae) is a relevant pest in the Palearctic region vineyards and is present in the Americas. Their management...
The European grapevine moth (EGVM) (Lepidoptera: Tortricidae) is a relevant pest in the Palearctic region vineyards and is present in the Americas. Their management using biological control agents and environmentally friendly biotechnical tools would reduce intensive pesticide use. The entomopathogenic nematodes (EPNs) in the families Steinernematidae and Heterorhabditidae are well-known virulent agents against arthropod pests thanks to symbiotic bacteria in the genera and (respectively) that produce natural products with insecticidal potential. Novel technological advances allow field applications of EPNs and those bioactive compounds as powerful bio-tools against aerial insect pests. This study aimed to determine the viability of four EPN species (, , , and ) as biological control agents against EGVM larval instars (L1, L3, and L5) and pupae. Additionally, the bioactive compounds from their four symbiotic bacteria (, , , and subsp. respectively) were tested as unfiltered ferment (UF) and cell-free supernatant (CFS) against the EGVM larval instars L1 and L3. All of the EPN species showed the capability of killing EGVM during the larval and pupal stages, particularly (mortalities of ~50% for L1 and >75% for L3 and L5 in only two days), followed by efficacy by . Similarly, the bacterial bioactive compounds produced higher larval mortality at three days against L1 (>90%) than L3 (~50%), making the application of UF more virulent than the application of CFS. Our findings indicate that both steinernematid species and their symbiotic bacterial bioactive compounds could be considered for a novel agro-technological approach to control in vineyards. Further research into co-formulation with adjuvants is required to expand their viability when implemented for aboveground grapevine application.
PubMed: 34821833
DOI: 10.3390/insects12111033 -
Marine Drugs Dec 2017In aquaculture, shrimp farming is a popular field. The benefits of shrimp farming include a relatively short grow-out time, high sale price, and good cost recovery.... (Review)
Review
In aquaculture, shrimp farming is a popular field. The benefits of shrimp farming include a relatively short grow-out time, high sale price, and good cost recovery. However, outbreaks of serious diseases inflict serious losses, and acute hepatopancreatic necrosis disease (AHPND) is an emerging challenge to this industry. In South American white shrimp () and grass shrimp (), this disease has a 70-100% mortality. The pathogenic agent of AHPND is a specific strain of which contains PirA and PirB toxins encoded in the pVA1 plasmid. PirA and PirB have been shown to cause the typical histological symptoms of AHPND in infected shrimps, and in this review, we will focus on our structural understanding of these toxins. By analyzing their structures, a possible cytotoxic mechanism, as well as strategies for anti-AHPND drug design, is proposed.
Topics: Animals; Aquaculture; Aquatic Organisms; Bacterial Proteins; Penaeidae; Toxins, Biological; Vibrio parahaemolyticus
PubMed: 29194352
DOI: 10.3390/md15120373 -
Infection and Immunity May 2018is an outstanding model for studying host antipathogen defense. Although substantial progress has been made in understanding how metabolism and immunity are...
is an outstanding model for studying host antipathogen defense. Although substantial progress has been made in understanding how metabolism and immunity are interrelated in flies, little information has been obtained on the molecular players that regulate metabolism and inflammation in during pathogenic infection. Recently, we reported that the inactivation of thioester-containing protein 2 () and promotes survival and decreases the bacterial burden in flies upon infection with the virulent pathogens and Here, we investigated physiological and pathological defects in mutant flies in response to challenge. We find that and loss-of-function mutant flies contain increased levels of carbohydrates and triglycerides in the presence or absence of infection. We also report that infection leads to higher levels of nitric oxide and reduced transcript levels of the apical caspase-encoding gene in and mutants. We show that and are upregulated mainly in the fat body rather than the gut in -infected wild-type flies and that mutants contain decreased numbers of bacteria in both tissue types. We propose that the inactivation of or in adult flies results in lower levels of inflammation and increased energy reserves in response to , which could confer a survival-protective effect during the initial hours of infection.
Topics: Animals; Drosophila Proteins; Drosophila melanogaster; Host-Pathogen Interactions; Immunity, Innate; Inflammation
PubMed: 29463615
DOI: 10.1128/IAI.00810-17 -
Cellular Microbiology Oct 2007Bioluminescence imaging (BLI) has emerged as a powerful new method to analyse infectious diseases in animal models. BLI offers real-time monitoring of spatial and... (Review)
Review
Bioluminescence imaging (BLI) has emerged as a powerful new method to analyse infectious diseases in animal models. BLI offers real-time monitoring of spatial and temporal progression of infection in the same animal, as opposed to euthanizing a cohort of animals and quantifying colony or plaque forming units at multiple time points. Pathogens or mice are engineered to express genetically encoded luciferase enzymes from bacteria, insects, or the sea pansy. The seminal study showing the feasibility of detecting microbially generated luminescence within a living mouse was published by Contag and colleagues in 1995, using Salmonella typhimurium transformed with the lux operon from Photorhabdus luminescens. Following this, they and others performed many studies of infection by bioluminescent Gram-negative and Gram-positive bacteria. Viruses can also be engineered to encode luciferase. Our laboratory has used bioluminescent reporter viruses to follow HSV and vaccinia pathogenesis; others have used an alphavirus or novirhabdovirus. Recently, even eukaryotic parasites Plasmodium, Leishmania and Toxoplasma have been transformed with luciferase and yielded unique insights into their in vivo behaviour. We expect that both the range of organisms and the molecular events able to be studied by BLI will continue to expand, yielding important insights into mechanisms of pathogenesis.
Topics: Animals; Communicable Diseases; Genes, Reporter; Gram-Positive Bacteria; Leishmania; Luciferases; Luminescent Measurements; Mice; Microbiological Techniques; Mycoses; Parasitic Diseases; Plasmodium; Toxoplasma; Virus Diseases; Viruses
PubMed: 17587328
DOI: 10.1111/j.1462-5822.2007.00995.x -
Advanced Science (Weinheim,... Jun 2024Pigments such as anthraquinones (AQs) and melanins are antioxidants, protectants, or virulence factors. AQs from the entomopathogenic bacterium Photorhabdus laumondii...
Pigments such as anthraquinones (AQs) and melanins are antioxidants, protectants, or virulence factors. AQs from the entomopathogenic bacterium Photorhabdus laumondii are produced by a modular type II polyketide synthase system. A key enzyme involved in AQ biosynthesis is PlAntI, which catalyzes the hydrolysis of the bicyclic-intermediate-loaded acyl carrier protein, polyketide trimming, and assembly of the aromatic AQ scaffold. Here, multiple crystal structures of PlAntI in various conformations and with bound substrate surrogates or inhibitors are reported. Structure-based mutagenesis and activity assays provide experimental insights into the three sequential reaction steps to yield the natural product AQ-256. For comparison, a series of ligand-complex structures of two functionally related hydrolases involved in the biosynthesis of 1,8-dihydroxynaphthalene-melanin in pathogenic fungi is determined. These data provide fundamental insights into the mechanism of polyketide trimming that shapes pigments in pro- and eukaryotes.
Topics: Anthraquinones; Polyketides; Melanins; Polyketide Synthases; Photorhabdus; Naphthols; Pigments, Biological
PubMed: 38491909
DOI: 10.1002/advs.202400184 -
Gene Aug 2021The genome sequences of entomopathogenic nematode (EPN) bacteria and their functional analyses can lead to the genetic engineering of the bacteria for use as biocontrol...
Genome assembly and annotation of Photorhabdus heterorhabditis strain ETL reveals genetic features involved in pathogenicity with its associated entomopathogenic nematode and anti-host effectors with biocontrol potential applications.
The genome sequences of entomopathogenic nematode (EPN) bacteria and their functional analyses can lead to the genetic engineering of the bacteria for use as biocontrol agents. The bacterial symbiont Photorhabdus heterorhabditis strain ETL isolated from an insect pathogenic nematode, Heterorhabditis zealandica strain ETL, collected in the northernmost region of South Africa was studied to reveal information that can be useful in the design of improvement strategies for both effective and liquid production method of EPN-based pesticides. The strain ETL genome was found closely related to the type strain genome of P. australis DSM 17,609 (~60 to 99.9% CDSs similarity), but closely related to the not yet genome-sequenced type strain, P. heterorhabditis. It has a genome size of 4,866,148 bp and G + C content of 42.4% similar to other Photorhabdus. It contains 4,351 protein coding genes (CDSs) of which, at least 84% are shared with the de facto type strain P. luminescens subsp. laumondii TTO1, and has 318 unknown CDSs and the genome has a higher degree of plasticity allowing it to adapt to different environmental conditions, and to be virulent against various insects; observed through genes acquired through horizontal gene transfer mechanisms, clustered regularly interspaced short palindromic repeats, non-determined polyketide- and non-ribosomal peptide- synthase gene clusters, and many genes associated with uncharacterized proteins; which also justify the strain ETL's genes differences (quantity and quality) compared to P. luminescens subsp. laumondii TTO1. The protein coding sequences contained genes with both bio-engineering and EPNs mass production importance, of which numerous are uncharacterized.
Topics: Animals; Base Sequence; Biological Control Agents; Genes, Bacterial; Genome, Bacterial; Host-Pathogen Interactions; Molecular Sequence Annotation; Photorhabdus; Phylogeny; Strongyloidea; Virulence
PubMed: 34147570
DOI: 10.1016/j.gene.2021.145780 -
Applied and Environmental Microbiology Oct 2016Insect larvae killed by entomopathogenic nematodes are thought to contain bacterial communities dominated by a single bacterial genus, that of the nematode's bacterial...
UNLABELLED
Insect larvae killed by entomopathogenic nematodes are thought to contain bacterial communities dominated by a single bacterial genus, that of the nematode's bacterial symbiont. In this study, we used next-generation sequencing to profile bacterial community dynamics in greater wax moth (Galleria mellonella) larvae cadavers killed by Heterorhabditis nematodes and their Photorhabdus symbionts. We found that, although Photorhabdus strains did initially displace an Enterococcus-dominated community present in uninfected G. mellonella insect larvae, the cadaver community was not static. Twelve days postinfection, Photorhabdus shared the cadaver with Stenotrophomonas species. Consistent with this result, Stenotrophomonas strains isolated from infected cadavers were resistant to Photorhabdus-mediated toxicity in solid coculture assays. We isolated and characterized a Photorhabdus-produced antibiotic from G. mellonella cadavers, produced it synthetically, and demonstrated that both the natural and synthetic compounds decreased G. mellonella-associated Enterococcus growth, but not Stenotrophomonas growth, in vitro Finally, we showed that the Stenotrophomonas strains described here negatively affected Photorhabdus growth in vitro Our results add an important dimension to a broader understanding of Heterorhabditis-Photorhabdus biology and also demonstrate that interspecific bacterial competition likely characterizes even a theoretically monoxenic environment, such as a Heterorhabditis-Photorhabdus-parasitized insect cadaver.
IMPORTANCE
Understanding, and eventually manipulating, both human and environmental health depends on a complete accounting of the forces that act on and shape microbial communities. One of these underlying forces is hypothesized to be resource competition. A resource that has received little attention in the general microbiological literature, but likely has ecological and evolutionary importance, is dead/decaying multicellular organisms. Metazoan cadavers, including those of insects, are ephemeral and nutrient-rich environments, where resource competition might shape interspecific macrobiotic and microbiotic interactions. This study is the first to use a next-generation sequencing approach to study the community dynamics of bacteria within a model insect cadaver system: insect larvae parasitized by entomopathogenic nematodes and their bacterial symbionts. By integrating bioinformatic, biochemical, and classic in vitro microbiological approaches, we have provided mechanistic insight into how antibiotic-mediated bacterial interactions may shape community dynamics within insect cadavers.
Topics: Animals; Anti-Bacterial Agents; Cadaver; Larva; Microbiota; Moths; Photorhabdus; RNA, Bacterial; RNA, Ribosomal, 16S; Rhabditida; Sequence Analysis, DNA; Stenotrophomonas; Stilbenes
PubMed: 27451445
DOI: 10.1128/AEM.01211-16 -
Insects Jan 2020The fruit fly forms a magnificent model for interpreting conserved host innate immune signaling and functional processes in response to microbial assaults. In the broad... (Review)
Review
The fruit fly forms a magnificent model for interpreting conserved host innate immune signaling and functional processes in response to microbial assaults. In the broad research field of host-microbe interactions, model hosts are used in conjunction with a variety of pathogenic microorganisms to disentangle host immune system activities and microbial pathogenicity strategies. The pathogen is considered an established model for analyzing bacterial virulence and symbiosis due to its unique life cycle that extends between two invertebrate hosts: an insect and a parasitic nematode. In recent years, particular focus has been given to the mechanistic participation of the thioester-containing proteins (TEPs) in the overall immune capacity of the fly upon response against the pathogen alone or in combination with its specific nematode vector . The original role of certain TEPs in the insect innate immune machinery was linked to the antibacterial and antiparasite reaction of the mosquito malaria vector ; however, revamped interest in the immune competence of these molecules has recently emerged from the - infection system. Here, we review the latest findings on this topic with the expectation that such information will refine our understanding of the evolutionary immune role of TEPs in host immune surveillance.
PubMed: 32013030
DOI: 10.3390/insects11020085 -
Virulence Nov 2017
Topics: Animals; Immunity, Innate; Photorhabdus; Rhabditoidea
PubMed: 28704162
DOI: 10.1080/21505594.2017.1355662 -
ELife Sep 2019The proteins injected by bacteria into eukaryotic organisms can lead to fates as diverse as death and metamorphosis.
The proteins injected by bacteria into eukaryotic organisms can lead to fates as diverse as death and metamorphosis.
Topics: Bacterial Proteins; Eukaryotic Cells; Photorhabdus; Virulence
PubMed: 31526473
DOI: 10.7554/eLife.50815