We acknowledge financial support from the Natural Science Foundation of Hainan Province (Grant no. 323QN262), the National Natural Science Foundation of China (Grant no. 31701843 and 32172483), the Jiangsu Agriculture Science and Technology Innovation Fund (Grant No. CX(22)3012 and CX(21)3008), the &#34;Shuangchuang Doctor&#34; Foundation of Jiangsu Province (Grant No. 202030472), and the Nanjing Agricultural University startup fund (Grant No. 804018).

1. Insect rearing
<ol>
	<li>Feed Corcyra cephalonica on corn flour at a temperature of 26 &#177; 1&#176;C and a relative humidity of 40% &#177; 10%.</li>
	<li>Breed T. dendrolimi strain from the Jilin insectary indoors using the eggs of Corcyra cephalonica as hosts. Feed wasp adults 10% sucrose water in Drosophila tubes at a temperature of 26 &#177; 1 &#176;C, relative humidity of 70% &#177; 10%, light (L): dark (D) period of 14 h: 10 h.</li>
</ol>
2. Preparation of polyethylene plastic film egg cards
<ol>
	<li>Take a polyethylene plastic film with a length of 16 cm, a width of 12 cm, and a thickness of 20 &#181;m. Press out 30 semicircular protrusions with a diameter of 2-3 mm and a height of approximately 3 mm using a glass grinding rod according to the standard PCR plate layout of 96 holes. 
	NOTE: The process of pressing out 30 semicircular protrusions using a glass grinding rod needs to be done paying attention to the pressure because too hard a press will puncture the plastic and contaminate the extracted venomless grinding rod.</li>
	<li>Disinfect the pressed polyethylene plastic film by exposing both sides to ultraviolet (UV) light for 1 h.</li>
	<li>Add a small amount of 10% polyvinyl alcohol to the semicircular surface.</li>
</ol>
3. Trichogramma dendrolimi parasitism
<ol>
	<li>After CO2 anesthesia, place T. dendrolimi female wasps into a collection box, and the number of wasps was ~3000.</li>
	<li>Place the convex side of the film egg card toward the collection box and secure the edges with a rubber band.</li>
	<li>Add 4 &#181;L of amino acid solution (6 g/L leucine, 4 g/L phenylalanine, 4.25 g/L histidine) to each semicircular protrusion. Cover it with a flat polyethylene plastic film 16 cm long and 12 cm wide. Use a rubber band to tightly cover the collection box with two sheets of plastic.</li>
	<li>Let T. dendrolimi wasps parasitize freely for 4-8 h and provide 10% sucrose water through wetted cotton.</li>
</ol>
4. Collecting T. dendrolimi venom
<ol>
	<li>Obtain the parasitized amino acid solution from the inner protrusion of the artificial egg card and transfer it to the cap of 1.5 mL tubes.</li>
	<li>Cover the tube cap with a 10 &#181;m nylon net with a 25 mm diameter, fasten the nylon net and centrifuge tube tightly. Place the centrifuge tube upright for short centrifugation using a mini-centrifuge (1360 x g) for 10 s and collect the filtered solution (~100 &#181;L of T. dendrolimi venom).</li>
	<li>Measure the concentration of collected T. dendrolimi venom using a Bicinchoninic acid (BCA) assay kit (Table of Materials).</li>
	<li>Store the venom at -80 &#176;C for further analyses.</li>
</ol>
5. SDS-PAGE analyses
<ol>
	<li>Add 30 &#181;L of T. dendrolimi venom to 10 &#181;L of 4x sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) sample loading buffer (Table of Materials) and heat at 95 &#176;C for 10 min.</li>
	<li>Perform SDS-PAGE gel run at 130 V for 120 min.</li>
	<li>Stain and decolorize the SDS-PAGE gel using the protein staining apparatus (Table of Materials).</li>
</ol>

Artificial Host Parasitization by Trichogramma dendrolimi and Venom Extraction

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	<li>Pennacchio, F., Strand, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evolution+of+developmental+strategies+in+parasitic+hymenoptera.">Evolution of developmental strategies in parasitic hymenoptera.</a> Annual Review of Entomology. 51, 233-258 (2006).</li><li>Yan, Z. C., Ye, X. H., Wang, B. B., Fang, Q., Ye, G. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Research+advances+on+composition,+function+and+evolution+of+venom+proteins+in+parasitoid+wasps.">Research advances on composition, function and evolution of venom proteins in parasitoid wasps.</a> Chinese Journal of Biological Control. 33 (1), 1-10 (2017).</li><li>Asgari, S., Rivers, D. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Venom+proteins+from+endoparasitoid+wasps+and+their+role+in+host-parasite+interactions.">Venom proteins from endoparasitoid wasps and their role in host-parasite interactions.</a> Annual Review of Entomology. 56, 313-335 (2011).</li><li>Moreau, S. J. M., Guillot, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Advances+and+prospects+on+biosynthesis,+structures,+and+functions+of+venom+proteins+from+parasitic+wasps.">Advances and prospects on biosynthesis, structures, and functions of venom proteins from parasitic wasps.</a> Insect Biochemistry and Molecular Biology. 35 (11), 1209-1223 (2005).</li><li>Yan, Z. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+venom+serpin+splicing+isoform+of+the+endoparasitoid+wasp+Pteromalus+puparum+suppresses+host+prophenoloxidase+cascade+by+forming+complexes+with+host+hemolymph+proteinases.">A venom serpin splicing isoform of the endoparasitoid wasp Pteromalus puparum suppresses host prophenoloxidase cascade by forming complexes with host hemolymph proteinases.</a> Journal Biological Chemistry. 292 (3), 1038-1051 (2017).</li><li>Woelke, J. 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The author has nothing to disclose and no competing financial interests.

Here, we present a method for extracting venom from T. dendrolimi using artificial hosts. The key points in the venom collection experiment are as follows. (1) During preparation, T. dendrolimi must be anesthetized rapidly with an appropriate concentration of CO2. If the CO2 concentration is too low, it will be insufficient to anesthetize the Trichogramma quickly. Conversely, if the concentration is too high, Trichogramma may die, reducing their ability to parasit...

Parasitoid wasps are parasitic hymenopteran insects that are important resources for biological control1. There is a wide variety of parasitoid wasps, with over 600,000 estimated species2. The diversity of parasitoid wasps far exceeds that of other venomous arthropods, such as snakes, cone snails, spiders, scorpions, and bees. Venom is an important parasitic factor in parasitoid wasps. For successful parasitism, venom is injected into the host, modulating the host&#39;s behavior, immunity, development, and metabolism3. Moreover, the venom of parasitoid wasps displays remarkable diversity in its molecular structures, targets, and functions, reflecting complex coevolution with their hosts. Thus, parasitoid venom is a valuable and underappreciated resource of active molecules for insecticidal or medical purposes4. Unlike the venom of snakes, cone snails, spiders, scorpions, and bees, parasitoid wasp venom cannot be collected by direct stimulation or electrical stimulation5. The current method of extraction of parasitoid wasp venom is to dissect the venom reservoir. However, parasitoid wasps are often small, and dissection of parasitoid wasps requires high technical skills. Therefore, if we can find a way to collect the venom of parasitoid wasps efficiently and conveniently, it will be of great help to research the venom of parasitoid wasps.
Trichogramma (Hymenoptera: Trichogrammatidae) is a genus of tiny (~0.5 mm long) parasitoid wasps6. These wasps are among the most widely used biocontrol agents, particularly targeting eggs of various lepidopteran pests in both agriculture and forests. For example, T. dendrolimi, one of the most widely used Trichogramma species in China, has been extensively applied to control a variety of agricultural and forestry pests, such as Dendrolimus superans, Ostrinia furnacalis, and Chilo suppressalis. Previous studies showed that Trichogramma wasps could inject their eggs into artificial hosts7. Artificial hosts can be created using materials such as wax8, agar9, Parafilm10, and plastic film11. The solution in artificial hosts that induces sufficient oviposition for Trichogramma can be simple, such as amino acids or inorganic salts12. Based on the characteristic that T. dendrolimi can parasitize artificial hosts, this study provides a new method for extracting venom from parasitoid wasps using artificial hosts. This approach aims to address the shortcomings of low yield, low purity, and susceptibility to contamination in current extraction techniques. By using this method, a large amount of high-purity venom from T. dendrolimi can be extracted, which meets the needs of scientific research and screening of bioactive molecules for insecticidal or medical purposes.

<table><tbody><tr><td>10 &amp;mu;m Nylon Net</td><td>Millipore</td><td>NY1002500</td><td>For filtering the eggs</td></tr><tr><td>10% Polyvinyl alcohol</td><td>Aladdin</td><td>P139533</td><td>For attractting&amp;nbsp; &lt;em&gt;T. dendrolimi&amp;nbsp; &lt;/em&gt;to lay eggs</td></tr><tr><td>10% Sucrose water</td><td>Sinopharm Chemical Reagent&amp;nbsp;</td><td>10021463</td><td>Feed &lt;em&gt;Trichogramma dendrolimi&lt;/em&gt;</td></tr><tr><td>4x LDS loading buffer</td><td>Ace Hardware</td><td>B23010301</td><td>SDS-PAGE</td></tr><tr><td>Collection box</td><td>Deli</td><td>8555</td><td>Container for &lt;em&gt;T. dendrolimi &lt;/em&gt;parasitism</td></tr><tr><td>Future PAGE&amp;nbsp; 4&amp;ndash;12% (12 wells)</td><td>Ace Hardware</td><td>J70236502X</td><td>SDS-PAGE</td></tr><tr><td>GenScript eStain L1 protein staining apparatus</td><td>GenScript</td><td>L00753</td><td>SDS-PAGE</td></tr><tr><td>Glass grinding rod&amp;nbsp;&amp;nbsp;</td><td>Applygen</td><td>tb6268</td><td>Semicircular protrudations&amp;nbsp;</td></tr><tr><td>L- Leucine</td><td>Solarbio</td><td>L0011</td><td>Artificial host components</td></tr><tr><td>L-Histidine</td><td>Aladdin</td><td>A2219458</td><td>Artificial host components</td></tr><tr><td>L-Phenylalanine</td><td>Solarbio</td><td>P0010</td><td>Artificial host components</td></tr><tr><td>Mini-Centrifuges</td><td>Scilogex</td><td>D1008</td><td>Centrifuge</td></tr><tr><td>MOPS-SDS running buffer</td><td>Ace Hardware</td><td>B23021</td><td>SDS-PAGE</td></tr><tr><td>Omni-Easy Instant BCA protein assay kit</td><td>Shanghai Yamay Biomedical Technology&amp;nbsp;</td><td>ZJ102</td><td>For esimation of venom protein concentration</td></tr><tr><td>PCR plate layout of 96 holes</td><td>Thermo Fisher</td><td>AB1400L</td><td>Semicircular protrudations&amp;nbsp;</td></tr><tr><td>Polyethylene plastic film</td><td>Suzhou Aopang Trading &amp;nbsp;</td><td>001c5427</td><td>Artificial egg card</td></tr><tr><td>Prestained color protein marker(10&amp;ndash;180 kDa)</td><td>YiFeiXue Biotech</td><td>YWB007</td><td>SDS-PAGE</td></tr><tr><td>Rubber band</td><td>Guangzhou qianrui biology science and technology</td><td>009</td><td>Tighten the plastic film and the collection box</td></tr><tr><td>Silicone rubber septa mat, 96-well, round hole</td><td>Sangon Biotech</td><td>F504416-0001</td><td>Semicircular protrudations&amp;nbsp;</td></tr></tbody></table>

extracting venom from the parasitoid wasp trichogramma dendrolimi using an artificial host

Parasitoid wasps are a diverse group of hymenopteran insects that serve as invaluable resources for pest biocontrol. To ensure successful parasitism, parasitoid wasps inject venom into their hosts to suppress their hosts&#39; immunity, modulate hosts&#39; development, metabolism, and even behavior. With over 600,000 estimated species, the diversity of parasitoid wasps surpasses that of other venomous animals, such as snakes, cone snails, and spiders. Parasitoid wasp venom is an underexplored source of bioactive molecules with potential applications in pest control and medicine. However, collecting parasitoid venom is challenging due to the inability to use direct or electrical stimulation and the difficulty in dissection because of their small size. Trichogramma is a genus of tiny (~0.5 mm) egg parasitoid wasps that are widely used for the biological control of lepidopteran pests in both agriculture and forests. Here, we report a method for extracting venom from T. dendrolimi using artificial hosts. These artificial hosts are created with polyethylene film and amino acid solutions and then inoculated with Trichogramma wasps for parasitism. The venom was subsequently collected and concentrated. This method enables the extraction of large amounts of Trichogramma venom while avoiding contamination from other tissues caused by dissection, a common issue in venom reservoir dissection protocols. This innovative approach facilitates the study of Trichogramma venom, paving the way for new research and potential applications.

The protein concentration of representative venom samples was measured using the protein assay kit, with the results presented in Table 1. The results showed that the concentration of venom protein collected by this method ranged from 0.35 &#181;g/&#181;L to 0.46 &#181;g/&#181;L, while the negative control of amino acid solution only had a protein concentration of 0.03 &#181;g/&#181;L to 0.05 &#181;g/&#181;L. The concentration of venom protein collected by this method is much higher than that of negative...

Watch this Scientific Journal Video about Efficient Venom Extraction Method from Trichogramma Parasitoid Wasps at JoVE.com

Author Spotlight: Efficient Venom Extraction Method from Trichogramma Parasitoid Wasps 

Here, we present a protocol for extracting venom from Trichogramma dendrolimi using an artificial host created with polyethylene film and amino acid solution.

Extracting Venom from the Parasitoid Wasp Trichogramma dendrolimi Using an Artificial Host

Parasitoid wasps are a diverse group of hymenopteran insects that serve as invaluable resources for pest biocontrol. To ensure successful parasitism, ...

extracting-venom-from-parasitoid-wasp-trichogramma-dendrolimi-using

Universidad de Cartagena UDEC

Research

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Biochemistry

1.4K Views.  Nanjing Agricultural University. Here, we present a protocol for extracting venom from Trichogramma dendrolimi using an artificial host created with polyethylene film and amino acid solution.

Video: Author Spotlight: Efficient Venom Extraction Method from Trichogramma Parasitoid Wasps 

Mimicking the Function of Signaling Proteins: Toward Artificial Signal Transduction Therapy

Signal transduction pathways, which control the response of cells to various environmental signals, are mediated by the function of signaling proteins that interact with each other and activate one other with high specificity. Synthetic agents that mimic the function of these proteins might therefore be used to generate unnatural signal transduction steps and consequently, alter the cell's function. We present guidelines for designing 'chemical transducers' that can induce artificial communication between native proteins. In addition, we present detailed protocols for synthesizing and testing a specific 'transducer', which can induce communication between two unrelated proteins: platelet-derived growth-factor (PDGF) and glutathione-S-transferase (GST). The way by which this unnatural PDGF-GST communication could be used to control the cleavage of an anticancer prodrug is also presented, indicating the potential for using such systems in 'artificial signal transduction therapy'. This work is intended to facilitate developing additional 'transducers' of this class, which may be used to mediate intracellular protein-protein communication and consequently, to induce artificial cell signaling pathways.

We present guidelines for developing synthetic 'chemical transducers' that can induce communication between naturally unrelated proteins. In addition, detailed protocols are presented for synthesizing and testing a specific 'transducer' that enables a growth factor to activate a detoxifying enzyme and consequently, to regulate the cleavage of an anticancer prodrug.

Signal transduction pathways, which control the response of cells to various environmental signals, are mediated by the function of signaling proteins ...

Structural Information from Single-molecule FRET Experiments Using the Fast Nano-positioning System

Single-molecule F&#246;rster Resonance Energy Transfer (smFRET) can be used to obtain structural information on biomolecular complexes in real-time. Thereby, multiple smFRET measurements are used to localize an unknown dye position inside a protein complex by means of trilateration. In order to obtain quantitative information, the Nano-Positioning System (NPS) uses probabilistic data analysis to combine structural information from X-ray crystallography with single-molecule fluorescence data to calculate not only the most probable position but the complete three-dimensional probability distribution, termed posterior, which indicates the experimental uncertainty. The concept was generalized for the analysis of smFRET networks containing numerous dye molecules. The latest version of NPS, Fast-NPS, features a new algorithm using Bayesian parameter estimation based on Markov Chain Monte Carlo sampling and parallel tempering that allows for the analysis of large smFRET networks in a comparably short time. Moreover, Fast-NPS allows the calculation of the posterior by choosing one of five different models for each dye, that account for the different spatial and orientational behavior exhibited by the dye molecules due to their local environment.
Here we present a detailed protocol for obtaining smFRET data and applying the Fast-NPS. We provide detailed instructions for the acquisition of the three input parameters of Fast-NPS: the smFRET values, as well as the quantum yield and anisotropy of the dye molecules. Recently, the NPS has been used to elucidate the architecture of an archaeal open promotor complex. This data is used to demonstrate the influence of the five different dye models on the posterior distribution.

We present the setup and experimental procedure to obtain smFRET data from large donor-acceptor networks with a TIRF microscope. The step-by-step analysis of these measurements with the Bayesian inference software Fast-NPS yields high-resolved structural information via the application of adapted dye models.

Single-molecule F&#246;rster Resonance Energy Transfer (smFRET) can be used to obtain structural information on biomolecular complexes in real-time. ...

An Efficient Method for the Isolation of Highly Purified RNA from Seeds for Use in Quantitative Transcriptome Analysis

Plant seeds accumulate large amounts of storage reserves comprising biodegradable organic matter. Humans rely on seed storage reserves for food and as industrial materials. Gene expression profiles are powerful tools for investigating metabolic regulation in plant cells. Therefore, detailed, accurate gene expression profiles during seed development are required for crop breeding. Acquiring highly purified RNA is essential for producing these profiles. Efficient methods are needed to isolate highly purified RNA from seeds. Here, we describe a method for isolating RNA from seeds containing large amounts of oils, proteins, and polyphenols, which have inhibitory effects on high-purity RNA isolation. Our method enables highly purified RNA to be obtained from seeds without the use of phenol, chloroform, or additional processes for RNA purification. This method is applicable to Arabidopsis, rapeseed, and soybean seeds. Our method will be useful for monitoring the expression patterns of low level transcripts in developing and mature seeds.

We have succeeded in establishing a method for RNA isolation from plant seeds containing large amounts of oils, proteins, and polyphenols, which have inhibitory effects on high-purity RNA isolation. Our method is suitable for monitoring the expression of genes with low level transcripts in seeds.

Plant seeds accumulate large amounts of storage reserves comprising biodegradable organic matter. Humans rely on seed storage reserves for food and as ...

Mapping the Binding Site of an Aptamer on ATP Using MicroScale Thermophoresis

Characterization of molecular interactions in terms of basic binding parameters such as binding affinity, stoichiometry, and thermodynamics is an essential step in basic and applied science. MicroScale Thermophoresis (MST) is a sensitive biophysical method to obtain this important information. Relying on a physical effect called thermophoresis, which describes the movement of molecules through temperature gradients, this technology allows for the fast and precise determination of binding parameters in solution and allows the free choice of buffer conditions (from buffer to lysates/sera). MST uses the fact that an unbound molecule displays a different thermophoretic movement than a molecule that is in complex with a binding partner. The thermophoretic movement is altered in the moment of molecular interaction due to changes in size, charge, and hydration shell. By comparing the movement profiles of different molecular ratios of the two binding partners, quantitative information such as binding affinity (pM to mM) can be determined. Even challenging interactions between molecules of small sizes, such as aptamers and small compounds, can be studied by MST. Using the well-studied model interaction between the DH25.42 DNA aptamer and ATP, this manuscript provides a protocol to characterize aptamer-small molecule interactions. This study demonstrates that MST is highly sensitive and permits the mapping of the binding site of the 7.9 kDa DNA aptamer to the adenine of ATP.

MicroScale Thermophoresis (MST) is a sensitive technology to characterize aptamer-target interactions. This manuscript describes an MST protocol to characterize aptamer-small molecule interactions.

Characterization of molecular interactions in terms of basic binding parameters such as binding affinity, stoichiometry, and thermodynamics is an ...

Tandem Affinity Purification of Protein Complexes from Eukaryotic Cells

The purification of active protein-protein and protein-nucleic acid complexes is crucial for the characterization of enzymatic activities and de novo identification of novel subunits and post-translational modifications. Bacterial systems allow for the expression and purification of a wide variety of single polypeptides and protein complexes. However, this system does not enable the purification of protein subunits that contain post-translational modifications (e.g., phosphorylation and acetylation), and the identification of novel regulatory subunits that are only present/expressed in the eukaryotic system. Here, we provide a detailed description of a novel, robust, and efficient tandem affinity purification (TAP) method using STREP- and FLAG-tagged proteins that facilitates the purification of protein complexes with transiently or stably expressed epitope-tagged proteins from eukaryotic cells. This protocol can be applied to characterize protein complex functionality, to discover post-translational modifications on complex subunits, and to identify novel regulatory complex components by mass spectrometry. Notably, this TAP method can be applied to study protein complexes formed by eukaryotic or pathogenic (viral and bacterial) components, thus yielding a wide array of downstream experimental opportunities. We propose that researchers working with protein complexes could utilize this approach in many different ways.

We describe here a novel, robust, and efficient tandem affinity purification (TAP) method for the expression, isolation, and characterization of protein complexes from eukaryotic cells. This protocol could be utilized for the biochemical characterization of discrete complexes as well as the identification of novel interactors and post-translational modifications that regulate their function.

The purification of active protein-protein and protein-nucleic acid complexes is crucial for the characterization of enzymatic activities and de novo ...

An Introduction to Parasitic Wasps of Drosophila and the Antiparasite Immune Response

Most known parasitoid wasp species attack the larval or pupal stages of Drosophila. While Trichopria drosophilae infect the pupal stages of the host (Fig. 1A-C), females of the genus Leptopilina (Fig. 1D, 1F, 1G) and Ganaspis (Fig. 1E) attack the larval stages. We use these parasites to study the molecular basis of a biological arms race. Parasitic wasps have tremendous value as biocontrol agents. Most of them carry virulence and other factors that modify host physiology and immunity. Analysis of Drosophila wasps is providing insights into how species-specific interactions shape the genetic structures of natural communities. These studies also serve as a model for understanding the hosts' immune physiology and how coordinated immune reactions are thwarted by this class of parasites.
The larval/pupal cuticle serves as the first line of defense. The wasp ovipositor is a sharp needle-like structure that efficiently delivers eggs into the host hemocoel. Oviposition is followed by a wound healing reaction at the cuticle (Fig. 1C, arrowheads). Some wasps can insert two or more eggs into the same host, although the development of only one egg succeeds. Supernumerary eggs or developing larvae are eliminated by a process that is not yet understood. These wasps are therefore referred to as solitary parasitoids.
Depending on the fly strain and the wasp species, the wasp egg has one of two fates. It is either encapsulated, so that its development is blocked (host emerges; Fig. 2 left); or the wasp egg hatches, develops, molts, and grows into an adult (wasp emerges; Fig. 2 right). L. heterotoma is one of the best-studied species of Drosophila parasitic wasps. It is a "generalist," which means that it can utilize most Drosophila species as hosts1. L. heterotoma and L. victoriae are sister species and they produce virus-like particles that actively interfere with the encapsulation response2. Unlike L. heterotoma, L. boulardi is a specialist parasite and the range of Drosophila species it utilizes is relatively limited1. Strains of L. boulardi also produce virus-like particles3 although they differ significantly in their ability to succeed on D. melanogaster1. Some of these L. boulardi strains are difficult to grow on D. melanogaster1 as the fly host frequently succeeds in encapsulating their eggs. Thus, it is important to have the knowledge of both partners in specific experimental protocols.
In addition to barrier tissues (cuticle, gut and trachea), Drosophila larvae have systemic cellular and humoral immune responses that arise from functions of blood cells and the fat body, respectively. Oviposition by L. boulardi activates both immune arms1,4. Blood cells are found in circulation, in sessile populations under the segmented cuticle, and in the lymph gland. The lymph gland is a small hematopoietic organ on the dorsal side of the larva. Clusters of hematopoietic cells, called lobes, are arranged segmentally in pairs along the dorsal vessel that runs along the anterior-posterior axis of the animal (Fig. 3A). The fat body is a large multifunctional organ (Fig. 3B). It secretes antimicrobial peptides in response to microbial and metazoan infections.
Wasp infection activates immune signaling (Fig. 4)4. At the cellular level, it triggers division and differentiation of blood cells. In self defense, aggregates and capsules develop in the hemocoel of infected animals (Fig. 5)5,6. Activated blood cells migrate toward the wasp egg (or wasp larva) and begin to form a capsule around it (Fig. 5A-F). Some blood cells aggregate to form nodules (Fig. 5G-H). Careful analysis reveals that wasp infection induces the anterior-most lymph gland lobes to disperse at their peripheries (Fig. 6C, D).
We present representative data with Toll signal transduction pathway components Dorsal and Sp&auml;tzle (Figs. 4,5,7), and its target Drosomycin (Fig. 6), to illustrate how specific changes in the lymph gland and hemocoel can be studied after wasp infection. The dissection protocols described here also yield the wasp eggs (or developing stages of wasps) from the host hemolymph (Fig. 8).

An Introduction to Parasitic Wasps of Drosophila and the Antiparasite Immune Response

Parasitoid (parasitic) wasps constitute a major class of natural enemies of many insects including Drosophila melanogaster. We will introduce the techniques to propagate these parasites in Drosophila spp. and demonstrate how to analyze their effects on immune tissues of Drosophila larvae.

Most known parasitoid wasp species attack the larval or pupal stages of Drosophila. While Trichopria drosophilae infect the pupal stages of the host (Fig. ...

Immunology and Infection

Harvesting Venom Toxins from Assassin Bugs and Other Heteropteran Insects

Heteropteran insects such as assassin bugs (Reduviidae) and giant water bugs (Belostomatidae) descended from a common predaceous and venomous ancestor, and the majority of extant heteropterans retain this trophic strategy. Some heteropterans have transitioned to feeding on vertebrate blood (such as the kissing bugs, Triatominae; and bed bugs, Cimicidae) while others have reverted to feeding on plants (most Pentatomomorpha). However, with the exception of saliva used by kissing bugs to facilitate blood-feeding, little is known about heteropteran venoms compared to the venoms of spiders, scorpions and snakes.
One obstacle to the characterization of heteropteran venom toxins is the structure and function of the venom/labial glands, which are both morphologically complex and perform multiple biological roles (defense, prey capture, and extra-oral digestion). In this article, we describe three methods we have successfully used to collect heteropteran venoms. First, we present electrostimulation as a convenient way to collect venom that is often lethal when injected into prey animals, and which obviates contamination by glandular tissue. Second, we show that gentle harassment of animals is sufficient to produce venom extrusion from the proboscis and/or venom spitting in some groups of heteropterans. Third, we describe methods to harvest venom toxins by dissection of anaesthetized animals to obtain the venom glands. This method is complementary to other methods, as it may allow harvesting of toxins from taxa in which electrostimulation and harassment are ineffective. These protocols will enable researchers to harvest toxins from heteropteran insects for structure-function characterization and possible applications in medicine and agriculture.

Although many insects in the suborder Heteroptera (Insecta: Hemiptera) are venomous, their venom composition and the functions of their venom toxins are mostly unknown. This protocol describes methods to harvest heteropteran venoms for further characterization, using electrostimulation, harassment, and gland dissection.

Heteropteran insects such as assassin bugs (Reduviidae) and giant water bugs (Belostomatidae) descended from a common predaceous and venomous ancestor, ...

Environment

Extraction of Venom and Venom Gland Microdissections from Spiders for Proteomic and Transcriptomic Analyses

Venoms are chemically complex secretions typically comprising numerous proteins and peptides with varied physiological activities. Functional characterization of venom proteins has important biomedical applications, including the identification of drug leads or probes for cellular receptors. Spiders are the most species rich clade of venomous organisms, but the venoms of only a few species are well-understood, in part due to the difficulty associated with collecting minute quantities of venom from small animals. This paper presents a protocol for the collection of venom from spiders using electrical stimulation, demonstrating the procedure on the Western black widow (Latrodectus hesperus). The collected venom is useful for varied downstream analyses including direct protein identification via mass spectrometry, functional assays, and stimulation of venom gene expression for transcriptomic studies. This technique has the advantage over protocols that isolate venom from whole gland homogenates, which do not separate genuine venom components from cellular proteins that are not secreted as part of the venom. Representative results demonstrate the detection of known venom peptides from the collected sample using mass spectrometry. The venom collection procedure is followed by a protocol for dissecting spider venom glands, with results demonstrating that this leads to the characterization of venom-expressed proteins and peptides at the sequence level.

This article provides a protocol for the extraction of venom from spiders using electrical stimulation in order to 1) conduct proteomic characterization, 2) stimulate venom gland gene expression, and 3) perform functional studies of venoms. This is followed by a description of venom gland microdissections for gene expression studies.

Venoms are chemically complex secretions typically comprising numerous proteins and peptides with varied physiological activities. Functional ...

Biology

Rearing of Brazilian Yellow Scorpion for Venom Extraction

Captive Maintenance and Venom Extraction of Tityus serrulatus (Brazilian Yellow Scorpion) for Antivenom Production

Scorpion envenomation is a public health problem in several tropical and subtropical countries. Tityus serrulatus Lutz and Mello, 1922 (Brazilian yellow scorpion) are responsible for approximately 150,000 envenoming cases per year in Brazil, of which 10% require antivenom treatment to reverse life-threatening venom effects. Therefore, thousands of T. serrulatus individuals are maintained under controlled captivity conditions for venom extraction, subsequently used in the production of the national supply of scorpion antivenom. Instituto Butantan is the main antivenom-manufacturing laboratory in Brazil, providing about 70,000 vials of scorpion antivenom for the Brazilian health system. Thus, the husbandry protocols and venom extraction methodologies are key points for the success of large-scale, standardized venom production. The objective of this article is to describe the captivity protocols of T. serrulatus husbandry, encompassing the husbandry routine and the venom extraction procedures, following good manufacturing practices, and ensuring animal welfare. These practices allow for the maintenance of up to 20,000 animals in captivity, with a routine of 3,000 to 5,000 scorpions milked monthly according to antivenom manufacturing demand, achieving an average of 90% of positive extraction.

Author Spotlight: Optimizing Scorpion Venom Extraction for Antivenom Production 

Here, we present successful maintenance and venom extraction protocols for large-scale Tityus serrulatus Lutz and Mello, 1922 (Brazilian yellow scorpion) husbandry, with the aim of providing venom for subsequent scorpion antivenom production to meet the demand of the Brazilian health system.

Scorpion envenomation is a public health problem in several tropical and subtropical countries. Tityus serrulatus Lutz and Mello, 1922 (Brazilian yellow ...

Advancing RNAi Techniques in Trichogramma dendrolimi for Gene Function Analysis

RNA Interference in the Egg Parasitoid, Trichogramma dendrolimi Matsumura

The egg parasitoids, Trichogramma spp, are recognized as efficient biological control agents against various lepidopteran pests in agriculture and forests. The immature stages of Trichogramma offspring develop within the host egg, exhibiting remarkable diminutiveness (approximately 0.5 mm in adult length). RNA-interference (RNAi) methodology has emerged as a crucial tool for elucidating gene functions in numerous organisms. However, manipulating RNAi in certain small parasitoid species, such as Trichogramma, has generally posed significant challenges. In this study, we present an efficient RNAi method in Trichogramma denrolimi. The outlined procedure encompasses the acquisition and isolation of individual T. dendrolimi specimens from host eggs, the design and synthesis of double-stranded RNA (dsRNA), the in vitro transplantation and cultivation of T. dendrolimi pupae, the micro-injection of dsRNA, and the subsequent assessment of target gene knockdown through RT-qPCR analysis. This study furnishes a comprehensive, visually detailed procedure for conducting RNAi experiments in T. dendrolimi, thereby enabling researchers to investigate the gene regulation in this species. Furthermore, this methodology is adaptable for RNAi studies or micro-injections in other Trichogramma species with minor adjustments, rendering it a valuable reference for conducting RNAi experiments in other endoparasitic species.

Author Spotlight: Investigating Wolbachia-Induced Thelytokous Parthenogenesis and Genetic Toolkit Development Through RNA Interference

The manipulation of RNA interference (RNAi) presents a formidable challenge in many parasitoid species with diminutive size, such as Trichogramma wasps. This study delineated an efficient RNAi method in Trichogramma denrolimi. The present methodology provides a robust model for investigating gene regulation in Trichogramma wasps.

Extracting Venom from the Parasitoid Wasp Trichogramma dendrolimi Using an Artificial Host

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Harvesting Venom Toxins from Assassin Bugs and Other Heteropteran Insects

Extraction of Venom and Venom Gland Microdissections from Spiders for Proteomic and Transcriptomic Analyses

Captive Maintenance and Venom Extraction of Tityus serrulatus (Brazilian Yellow Scorpion) for Antivenom Production

RNA Interference in the Egg Parasitoid, Trichogramma dendrolimi Matsumura