Please visit <a href="http://www.springerprotocols.com/Abstract/doi/10.1007/978-1-59745-457-5_18">Springer Protocols</a> to learn more about the engineering baculovirus as an insecidical agent and the oral infection techniques used in this assay.

The authors have nothing to disclose.

protocols for oral infection of lepidopteran larvae with baculovirus

Baculoviruses are widely used both as protein expression vectors and as insect pest control agents. This video shows how lepidopteran larvae can be infected with polyhedra by droplet feeding and diet plug-based bioassays. This accompanying Springer Protocols section provides an overview of the baculovirus lifecycle and use of baculoviruses as insecticidal agents, including discussion of the pros and cons for use of baculoviruses as insecticides, and progress made in genetic enhancement of baculoviruses for improved insecticidal efficacy.

Watch this Scientific Journal Video about Protocols for Oral Infection of Lepidopteran Larvae with Baculovirus at JoVE.com

Protocols for Oral Infection of Lepidopteran Larvae with Baculovirus

In this video, we demonstrate oral infection techniques of lepidopteran larvae with baculovirus in order to determine insecticidal efficiency.

Baculoviruses are widely used both as protein expression vectors and as insect pest control agents. This video shows how lepidopteran larvae can be ...

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10.4K Views.  Iowa State University. In this video, we demonstrate oral infection techniques of lepidopteran larvae with baculovirus in order to determine insecticidal efficiency. 

Video: Protocols for Oral Infection of Lepidopteran Larvae with Baculovirus

Protocols for Microapplicator-assisted Infection of Lepidopteran Larvae with Baculovirus

Baculoviruses are widely used both as protein expression vectors and as insect pest control agents. . This video shows how lepidopteran larvae can be infected with microapplicator techniques in the gut with baculovirus polyhedra and in the hemolymph with budded virus. This accompanying Springer Protocols section provides an overview of the baculovirus lifecycle and use of baculoviruses as insecticidal agents.  Formulation and application of baculoviruses for pest control purposes are described elsewhere.

In this video, we demonstrate two microapplicator techniques used to infect of lepidopteran larvae with baculovirus in order to determine insecticidal efficiency.

Baculoviruses are widely used both as protein expression vectors and as insect pest control agents. . This video shows how lepidopteran larvae can be ...

Microgavage of Zebrafish Larvae

The zebrafish has emerged as a powerful model organism for studying intestinal development1-5, physiology6-11, disease12-16, and host-microbe interactions17-25. Experimental approaches for studying intestinal biology often require the in vivo introduction of selected materials into the lumen of the intestine. In the larval zebrafish model, this is typically accomplished by immersing fish in a solution of the selected material, or by injection through the abdominal wall. Using the immersion method, it is difficult to accurately monitor or control the route or timing of material delivery to the intestine. For this reason, immersion exposure can cause unintended toxicity and other effects on extraintestinal tissues, limiting the potential range of material amounts that can be delivered into the intestine. Also, the amount of material ingested during immersion exposure can vary significantly between individual larvae26. Although these problems are not encountered during direct injection through the abdominal wall, proper injection is difficult and causes tissue damage which could influence experimental results. We introduce a method for microgavage of zebrafish larvae. The goal of this method is to provide a safe, effective, and consistent way to deliver material directly to the lumen of the anterior intestine in larval zebrafish with controlled timing. Microgavage utilizes standard embryo microinjection and stereomicroscopy equipment common to most laboratories that perform zebrafish research. Once fish are properly positioned in methylcellulose, gavage can be performed quickly at a rate of approximately 7-10 fish/ min, and post-gavage survival approaches 100% depending on the gavaged material. We also show that microgavage can permit loading of the intestinal lumen with high concentrations of materials that are lethal to fish when exposed by immersion. To demonstrate the utility of this method, we present a fluorescent dextran microgavage assay that can be used to quantify transit from the intestinal lumen to extraintestinal spaces. This test can be used to verify proper execution of the microgavage procedure, and also provides a novel zebrafish assay to examine intestinal epithelial barrier integrity under different experimental conditions (e.g. genetic manipulation, drug treatment, or exposure to environmental factors). Furthermore, we show how gavage can be used to evaluate intestinal motility by gavaging fluorescent microspheres and monitoring their subsequent transit. Microgavage can be applied to deliver diverse materials such as live microorganisms, secreted microbial factors/toxins, pharmacological agents, and physiological probes. With these capabilities, the larval zebrafish microgavage method has the potential to enhance a broad range of research fields using the zebrafish model system.

We present a novel method for microgavage of larval zebrafish utilizing standard embryo microinjection and stereomicroscopy equipment. We demonstrate that microgavage is a safe and efficient technique useful for delivering controlled amounts of diverse materials specifically into the larval zebrafish intestinal lumen.

The zebrafish has emerged as a powerful model organism for studying intestinal development1-5, physiology6-11, disease12-16, and host-microbe ...

Micromanipulation Techniques Allowing Analysis of Morphogenetic Dynamics and Turnover of Cytoskeletal Regulators

Examining the spatiotemporal dynamics of proteins can reveal their functional importance in various contexts. In this article, it is discussed how fluorescent recovery after photobleaching (FRAP) and photoactivation techniques can be used to study the spatiotemporal dynamics of proteins in subcellular locations. We also show how these techniques enable straightforward determination of various parameters linked to actin cytoskeletal regulation and cell motility. Moreover, the microinjection of cells is additionally described as an alternative treatment (potentially preceding or complementing the aforementioned photomanipulation techniques) to trigger instantaneous effects of translocated proteins on cell morphology and function. Micromanipulation such as protein injection or local application of plasma membrane-permeable drugs or cytoskeletal inhibitors can serve as powerful tool to record immediate consequences of a given treatment on cell behavior at the single cell and subcellular level. This is exemplified here by immediate induction of lamellipodial cell edge protrusion by the injection of recombinant Rac1 protein, as established a quarter-century ago. In addition, we provide a protocol for determining the turnover of enhanced green fluorescent protein (EGFP)-VASP, an actin filament polymerase prominently accumulating at lamellipodial tips of B16-F1 cells, employing FRAP and including associated data analysis and curve fitting. We also present guidelines for estimating the rates of lamellipodial actin network polymerization, as exemplified by cells expressing EGFP-tagged &#946;-actin. Finally, instructions are given for how to investigate the rates of actin monomer mobility within the cell cytoplasm, followed by actin incorporation at sites of rapid filament assembly, such as the tips of protruding lamellipodia, using photoactivation approaches. None of these protocols is&#160;restricted to components or regulators of the actin cytoskeleton, but can easily be extended to explore in analogous fashion the spatiotemporal dynamics and function of proteins in various different subcellular structures or functional contexts.

We describe how micro- and photomanipulation techniques such as FRAP and photoactivation enable the determination of motility parameters and the spatiotemporal dynamics of proteins within migrating cells. Experimental readouts include subcellular dynamics and turnover of motility regulators or of the underlying actin cytoskeleton.

Examining the spatiotemporal dynamics of proteins can reveal their functional importance in various contexts. In this article, it is discussed how ...

Oral Bacterial Infection and Shedding in Drosophila melanogaster

The fruit fly Drosophila melanogaster is one of the best developed model systems of infection and innate immunity. While most work has focused on systemic infections, there has been a recent increase of interest in the mechanisms of gut immunocompetence to pathogens, which require methods to orally infect flies. Here we present a protocol to orally expose individual flies to an opportunistic bacterial pathogen (Pseudomonas aeruginosa) and a natural bacterial pathogen of D. melanogaster (Pseudomonas entomophila). The goal of this protocol is to provide a robust method to expose male and female flies to these pathogens. We provide representative results showing survival phenotypes, microbe loads, and bacterial shedding, which is relevant for the study of heterogeneity in pathogen transmission. Finally, we confirm that Dcy mutants (lacking the protective peritrophic matrix in the gut epithelium) and Relish mutants (lacking a functional immune deficiency (IMD) pathway), show increased susceptibility to bacterial oral infection. This protocol, therefore, describes a robust method to infect flies using the oral route of infection, which can be extended to the study of a variety genetic and environmental sources of variation in gut infection outcomes and bacterial transmission.

Oral Bacterial Infection and Shedding in Drosophila melanogaster

This protocol describes methods to orally expose and infect the fruit fly Drosophila melanogaster with bacterial pathogens, and to measure the number of infectious bacteria shed following gut infection. We further describe the effect of immune mutants on fly survival following oral bacterial infection.

The fruit fly Drosophila melanogaster is one of the best developed model systems of infection and innate immunity. While most work has focused on systemic ...

Protocols for Testing the Toxicity of Novel Insecticidal Chemistries to Mosquitoes

New classes of insecticides with novel modes of action are needed to control insecticide resistant populations of mosquitoes that transmit diseases such as Zika, dengue and malaria. Assays for rapid, high-throughput analyses of unformulated novel chemistries against mosquito larvae and adults are presented. We describe protocols for single point-dose and dose response assays to evaluate the toxicity of small molecule chemistries to the Aedes aegypti vector of Zika, dengue and yellow fever,&#160;the malaria vector, Anopheles gambiae and the northern house mosquito, Culex quinquefasciatus, on contact and via ingestion. As an example, we evaluated the toxicity of amitriptyline, a small molecule antagonist of G protein-coupled receptors, via larval, adult topical and adult blood-feeding assay. The protocols provide a starting point to investigate insecticide potential. Results are discussed in the context of additional experiments to explore product applications and mechanisms for delivery.

Protocols are described for assessing the toxicity of chemistries to immature and adult mosquitoes for development as new classes of larvicides, adulticides and endectocides. The protocols enable high-throughput testing of multiple chemistries at single-point dose and subsequent evaluation via dose response assay to determine toxicity on contact or via ingestion.

New classes of insecticides with novel modes of action are needed to control insecticide resistant populations of mosquitoes that transmit diseases such ...

A Bacterial Oral Feeding Assay with Antibiotic-Treated Mosquitoes

The mosquito midgut harbors a highly dynamic microbiome that affects the host metabolism, reproduction, fitness, and vector competence. Studies have been conducted to investigate the effect of gut microbes as a whole; however, different microbes could exert distinct effects toward the host. This article provides the methodology to study the effect of each specific mosquito gut microbe and the potential mechanism.
This protocol contains two parts. The first part introduces how to dissect the mosquito midgut, isolate cultivable bacteria colonies, and identify bacteria species. The second part provides the procedure to generate antibiotic-treated mosquitoes and reintroduce one specific bacteria species.

This article presents a protocol to investigate the effect of individual mosquito gut bacteria, including isolation and identification of mosquito midgut cultivable microbes, antibiotic depletion of mosquito gut bacteria, and reintroduce one specific bacteria species.

The mosquito midgut harbors a highly dynamic microbiome that affects the host metabolism, reproduction, fitness, and vector competence. Studies have been ...

Preparation of Virus-Enriched Inoculum for Oral Infection of Honey Bees (Apis mellifera)

Honey bees are of great ecological and agricultural importance around the world but are also subject to a variety of pressures that negatively affect bee health, including exposure to viral pathogens. Such viruses can cause a wide variety of devastating effects and can often be challenging to study due to multiple factors that make it difficult to separate the effects of experimental treatments from preexisting background infection. Here we present a method to mass produce large quantities of virus particles along with a high throughput bioassay to test viral infection and effects. Necessitated by the current lack of a continuous, virus-free honey bee cell line, viral particles are amplified in vivo using honey bee pupae, which are extracted from the hive in large volumes using minimally stressful methodology. These virus particles can then be used in honey bee cage bioassays to test inocula viability, as well as various other virus infection dynamics, including interactions with nutrition, pesticides, and other pathogens. A major advantage of using such particles is that it greatly reduces the chances of introducing unknown variables in subsequent experimentation when compared to current alternatives, such as infection via infected bee hemolymph or homogenate, though care should still be taken when sourcing the bees, to minimize background virus contamination. The cage assays are not a substitute for large-scale, field-realistic experiments testing virus infection effects at a colony level, but instead function as a method to establish baseline viral responses that, in combination with the semi-pure virus particles, can serve as important tools to examine various dimensions of honey bee-virus physiological interactions.

Preparation of Virus-Enriched Inoculum for Oral Infection of Honey Bees Apis mellifera

Here we describe two protocols: first to propagate, extract, purify, and quantify large quantities of honey bee non-enveloped virus particles, including a method for removing honey bee pupae and second to test the effects of viral infection using a highly repeatable, high-throughput cage bioassay.

Honey bees are of great ecological and agricultural importance around the world but are also subject to a variety of pressures that negatively affect bee ...

Process Development for the Production and Purification of Adeno-Associated Virus (AAV)2 Vector using Baculovirus-Insect Cell Culture System

Adeno-associated viruses (AAV) are promising vectors for gene therapy applications. Here, the AAV2 vector is produced by co-culture of Spodoptera frugiperda (Sf9) cells with Sf9 cells infected with baculovirus (BV)-AAV2-GFP (or therapeutic gene) and BV-AAV2-rep-cap in serum-free suspension culture. Cells are cultured in a flask in an orbital shaker or Wave bioreactor. To release the AAV particles, producer cells are lysed in buffer containing detergent, which is subsequently clarified by low-speed centrifugation and filtration. AAV particles are purified from the cell lysate using AVB Sepharose column chromatography, which binds AAV particles. Bound particles are washed with PBS to remove contaminants and eluted from the resin using sodium citrate buffer at pH 3.0. The acidic eluate is neutralized with alkaline Tris-HCl buffer (pH 8.0), diluted with phosphate-buffered saline (PBS), and further concentrated with tangential flow filtration (TFF). The protocol describes small-scale pre-clinical vector production compatible with scale-up to large-scale clinical-grade AAV manufacturing for human gene therapy applications.

Process Development for the Production and Purification of Adeno-Associated Virus AAV2 Vector using Baculovirus-Insect Cell Culture System

In this protocol, AAV2 vector is produced by co-culturing Spodoptera frugiperda (Sf9) insect cells with baculovirus (BV)-AAV2-green fluorescent protein (GFP) or therapeutic gene and BV-AAV2-rep-cap infected Sf9 cells in suspension culture. AAV particles are released from the cells using detergent, clarified, purified by affinity column chromatography, and concentrated by tangential flow filtration.

Adeno-associated viruses (AAV) are promising vectors for gene therapy applications. Here, the AAV2 vector is produced by co-culture of Spodoptera ...

Application of Passive Head Motion to Generate Defined Accelerations at the Heads of Rodents

Exercise is widely recognized as effective for various diseases and physical disorders, including those related to brain dysfunction. However, molecular mechanisms behind the beneficial effects of exercise are poorly understood. Many physical workouts, particularly those classified as aerobic exercises such as jogging and walking, produce impulsive forces at the time of foot contact with the ground. Therefore, it was speculated that mechanical impact might be implicated in how exercise contributes to organismal homeostasis. For testing this hypothesis on the brain, a custom-designed ''passive head motion'' (hereafter referred to as PHM) system was developed that can generate vertical accelerations with controlled and defined magnitudes and modes and reproduce mechanical stimulation that might be applied to the heads of rodents during treadmill running at moderate velocities, a typical intervention to test the effects of exercise in animals. By using this system, it was demonstrated that PHM recapitulates the serotonin (5-hydroxytryptamine, hereafter referred to as 5-HT) receptor subtype 2A (5-HT2A) signaling in the prefrontal cortex (PFC) neurons of mice. This work provides detailed protocols for applying PHM and measuring its resultant mechanical accelerations at rodents' heads.

The present protocol describes a custom-designed ''passive head motion'' system, which reproduces mechanical accelerations at rodents' heads generated during their treadmill running at moderate velocities. It allows dissecting mechanical factors/elements from the beneficial effects of physical exercise.

Exercise is widely recognized as effective for various diseases and physical disorders, including those related to brain dysfunction. However, molecular ...

The Establishment of a Murine Mandibular Molar Extraction Socket Healing Model

This study introduces the development of a molar extraction model in the murine mandible to provide a practicable model for studying alveolar bone regeneration and intramembranous ossification. C57/J6 mice were used to extract the mandibular first molar to establish this model. They were euthanized, and the bilateral mandibles harvested, at 1 week and 4 weeks post-surgery, respectively. Subsequent serial stereoscopic harvest, histological assessment, and immunofluorescence staining were performed to demonstrate successful surgery. Immediately after surgery, the stereoscopic images displayed an empty extraction socket. The hematoxylin and eosin (H&#38;E) at 1 week and Masson staining at 4 weeks post-surgery showed that the area of the original root was partially and fully filled with bone trabeculae, respectively. The immunofluorescence staining showed that, compared with the homeostasis side, the Sp7 expression increased at 1 week post-surgery, suggesting vigorous osteogenesis in the alveolar fossa. All these results demonstrated a practicable murine tooth extraction socket healing model. Upcoming studies revealing the mechanisms of jawbone defect healing or socket healing could adopt this method.

This protocol demonstrates step-by-step details of how to extract the mandibular first molar in the mouse. It provides an alternative method for researchers focusing on jawbone healing and regeneration.