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TEM images showing the basal (A and B) the middle regions (C and D) of the venom glands. (A) shows the nuclei (N) of three cells; however, it is not possible to observe the cellular borders of these cells due to the cytoplasm projections with many membrane evaginations including some attached to the basal lamina (arrows). One cell type in the superior position with an electron-dense cytoplasm and less invaginations (asterisk) can be seen distinctly from the other two lucent cells full of mitochondria (mt). (B) shows a small cell attached to the basal lamina (arrows) without cytoplasm projections. (C) shows a cell with enlarged endoplasmic reticulum cisterns (asterisks) and several mitochondria (mt) in the cytoplasm. (D) shows a cell with cytoplasm packed of collapsed endoplasmic reticulum cisterns (asterisks) and no visible mitochondria. Nucleus, N; mitochondria, mt; basal lamina, bl; muscle layer, Mu.
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Spiders belonging to the genus Phoneutria (Perty, 1833), most commonly known as 'armed' spiders, are among the most dangerous species in Brazil due to high toxicity of their venom, associated with their habit of invading domestic or specific areas such as banana plantations. The venom of Phoneutria spiders is secreted by a pair of venom glands loca...
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... TEM analysis of the venom glands showed the basal regions of the venom glands composed by cells attached to a thick basal lamina (Figs. 7A and B). In Fig. 7A, it is possible to see the nuclei of three cells. However, it is not possible to observe the cellular borders of these cells due to the cytoplasm projections with many membrane evaginations. There are several mitochondria inside these cyto- plasmic projections. In this same figure, it is also possible to observe one cell type in the ...
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... these cells due to the cytoplasm projections with many membrane evaginations. There are several mitochondria inside these cyto- plasmic projections. In this same figure, it is also possible to observe one cell type in the superior position with an electron dense cytoplasm and less invaginations, which is distinct from the other two lucent cells. Fig. 7B shows another basal area of the venom gland with a small cell attached to the basal lamina without cytoplasm projections but sur- rounded by projections of neighbor cells. Fig. 4. CLM of the venom milking and histological section. (A) and (B) Glass smears of the P. nigriventer first milking observed by CLM after being stained by the ...
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... the middle region of the venom glands, the TEM showed two types of cells differing from each other by the cytoplasmic organelles (Figs. 7C and D). In Fig. 7C, the cell has enlarged endoplasmic reticulum cisterns and several mitochondria in the cytoplasm. Distinctly, Fig. 7D shows a cell with cytoplasm packed of collapsed endoplasmic reticu- lum cisterns and no visible mitochondria. Fig. 8A shows several types of cells located in the venom glands. In the basal region close to the ...
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... the middle region of the venom glands, the TEM showed two types of cells differing from each other by the cytoplasmic organelles (Figs. 7C and D). In Fig. 7C, the cell has enlarged endoplasmic reticulum cisterns and several mitochondria in the cytoplasm. Distinctly, Fig. 7D shows a cell with cytoplasm packed of collapsed endoplasmic reticu- lum cisterns and no visible mitochondria. Fig. 8A shows several types of cells located in the venom glands. In the basal region close to the basal ...
Context 5
... the middle region of the venom glands, the TEM showed two types of cells differing from each other by the cytoplasmic organelles (Figs. 7C and D). In Fig. 7C, the cell has enlarged endoplasmic reticulum cisterns and several mitochondria in the cytoplasm. Distinctly, Fig. 7D shows a cell with cytoplasm packed of collapsed endoplasmic reticu- lum cisterns and no visible mitochondria. Fig. 8A shows several types of cells located in the venom glands. In the basal region close to the basal lamina, it is possible to see a small cell with electron lucent cytoplasm filled with mitochondria. The other cells have ...
Citations
... From the perspective of venom acquisition methods, the influence of tissue fragments in ACV was minimal compared to VR proteome. However, if these proteins are not secreted as venom proteins, does this indicate that H. hebetor venom also has a holocrine secretion mechanism, like Phoneutria nigriventer [50]? Or does it have venom vesicles, similar to Drosophila parasitoid wasps [51]? ...
Habrobracon hebetor is a parasitoid wasp capable of infesting many lepidopteran larvae. It uses venom proteins to immobilize host larvae and prevent host larval development, thus playing an important role in the biocontrol of lepidopteran pests. To identify and characterize its venom proteins, we developed a novel venom collection method using an artificial host (ACV), i.e., encapsulated amino acid solution in paraffin membrane, allowing parasitoid wasps to inject venom. We performed protein full mass spectrometry analysis of putative venom proteins collected from ACV and venom reservoirs (VRs) (control). To verify the accuracy of proteomic data, we also collected venom glands (VGs), Dufour’s glands (DGs) and ovaries (OVs), and performed transcriptome analysis. In this paper, we identified 204 proteins in ACV via proteomic analysis; compared ACV putative venom proteins with those identified in VG, VR, and DG via proteome and transcriptome approaches; and verified a set of them using quantitative real-time polymerase chain reaction. Finally, 201 ACV proteins were identified as potential venom proteins. In addition, we screened 152 and 148 putative venom proteins identified in the VG transcriptome and the VR proteome against those in ACV, and found only 26 and 25 putative venom proteins, respectively, were overlapped with those in ACV. Altogether, our data suggest proteome analysis of ACV in combination with proteome–transcriptome analysis of other organs/tissues will provide the most comprehensive identification of true venom proteins in parasitoid wasps.
... Uncontrolled microbial infection in such an environment could lead to rapid replication and potentially lethal infections. The gland is connected to the chelicerae by a venom duct [42,43]. The envenomation of targets (attackers or prey) therefore provides an opportunity for inoculation with microbes that could develop into an infection. ...
The venoms of spiders from the RTA (retro-lateral tibia apophysis) clade contain diverse short linear peptides (SLPs) that offer a rich source of therapeutic candidates. Many of these peptides have insecticidal, antimicrobial and/or cytolytic activities, but their biological functions are unclear. Here, we explore the bioactivity of all known members of the A-family of SLPs previously identified in the venom of the Chinese wolf spider (Lycosa shansia). Our broad approach included an in silico analysis of physicochemical properties and bioactivity profiling for cytotoxic, antiviral, insecticidal and antibacterial activities. We found that most members of the A-family can form α-helices and resemble the antibacterial peptides found in frog poison. The peptides we tested showed no cytotoxic, antiviral or insecticidal activities but were able to reduce the growth of bacteria, including clinically relevant strains of Staphylococcus epidermidis and Listeria monocytogenes. The absence of insecticidal activity may suggest that these peptides have no role in prey capture, but their antibacterial activity may help to defend the venom gland against infection. Key Contribution: We tested the A-family of short linear peptides from Lycosa shansia venom for potential cytotoxic, antiviral, antibacterial, and insecticidal activities, revealing moderate but broad-spectrum activity against bacteria.
... This secretion type is found in scorpions, spiders, hymenopterans (i.e. wasps, bees and ants), and the enigmatic platypus (Fig 3, Table 1) [13,[59][60][61][62][63][64][65][66]. The third secretion type, in which the accumulation of secretion (i.e., venom components) in the cytoplasm of the secretory cells cause disintegration of the entire cell, is referred to as holocrine secretion. ...
... These types of glands can be found in the venom glands of cone snails, certain spider species and teleost fish (Fig 3, Table 1) [59,60,[68][69][70][71][72][73][74][75][76][77]. Spiders utilise both apocrine and holocrine secretion mechanisms, depending on the species [13,60,61,78]. The secretion method in the venom glands of mammals is dependent on the ...
Scorpion venoms are mixtures of proteins, peptides and small molecular compounds with high specificity for ion channels and are therefore considered to be promising candidates in the venoms-to-drugs pipeline. Transcriptomes are important tools for studying the composition and expression of scorpion venom. Unfortunately, studying the venom gland transcriptome traditionally requires sacrificing the animal and therefore is always a single snapshot in time. This paper describes a new way of generating a scorpion venom gland transcriptome without sacrificing the animal, thereby allowing the study of the transcriptome at various time points within a single individual. By comparing these venom-derived transcriptomes to the traditional whole-telson transcriptomes we show that the relative expression levels of the major toxin classes are similar. We further performed a multi-day extraction using our proposed method to show the possibility of doing a multiple time point transcriptome analysis. This allows for the study of patterns of toxin gene activation over time a single individual, and allows assessment of the effects of diet, season and other factors that are known or likely to influence intraindividual venom composition. We discuss the gland characteristics that may allow this method to be successful in scorpions and provide a review of other venomous taxa to which this method may potentially be successfully applied.
... Internally, the venom system of each chelicera consists of a venom gland connected to a narrow opening at the fang tip via a thin venom duct as shown in Fig. 3 (Foelix, 1983;Schmidtberg et al., 2021). Each venom gland is embedded in muscles and nerves, enabling fine control of venom release (Çavuşo glu et al., 2005;Silva et al., 2008;Benli et al., 2013). Localization of venom glands differs between orthognathous and labidognathous types. ...
Spiders are diverse, predatory arthropods that have inhabited Earth for around 400 million years. They are well known for their complex venom systems that are used to overpower their prey. Spider venoms contain many proteins and pep-tides with highly specific and potent activities suitable for biomedical or agrochemical applications, but the key role of venoms as an evolutionary innovation is often overlooked, even though this has enabled spiders to emerge as one of the most successful animal lineages. In this review, we discuss these neglected biological aspects of spider venoms. We focus on the morphology of spider venom systems, their major components, biochemical and chemical plasticity, as well as ecological and evolutionary trends. We argue that the effectiveness of spider venoms is due to their unprecedented complexity, with diverse components working synergistically to increase the overall potency. The analysis of spider venoms is difficult to standardize because they are dynamic systems, fine-tuned and modified by factors such as sex, life-history stage and biological role. Finally, we summarize the mechanisms that drive spider venom evolution and highlight the need for genome-based studies to reconstruct the evolutionary history and physiological networks of spider venom compounds with more certainty.
... Rhodnius domesticus), as well as in SGs of other insects, such as bed bugs (Cimex hemipterus), spittlebugs (Mahanarva fimbriolata) and armed spiders (Phoneutria nigriventer) [24][25][26]. ...
... Rhodnius domesticus), as well as in SGs of other insects, such as bed bugs (Cimex hemipterus), spittlebugs (Mahanarva fimbriolata) and armed spiders (Phoneutria nigriventer) [24][25][26]. ...
Rhodnius prolixus is the principal vector of Trypanosoma cruzi , the aetiological agent of Chagas disease in American countries. This insect is haematophagous during all life cycles and, to antagonize its haemostatic, inflammatory and immune systems, it secretes saliva while feeding on the vertebrate host's blood. Here, we investigated characteristic changes of the salivary glands (SG) that occur during insect development. Two pairs of lobules and ducts comprise the SG of R. prolixus . The organ's size increases over time, but the microanatomical structures are preserved during insect development. Both lobules have a single layer epithelium formed by binucleated cells, which surrounds the saliva reservoir. The principal lobule presents higher polysaccharide and total protein contents than the accessory lobe. A network of external muscle layers is responsible for organ contraction and saliva release. Apocrine, merocrine and holocrine secretion types occur in the secretory epithelium. Dopamine, serotonin and tyrosine-hydroxylase are neural-related molecules that regulate SG function both during and after feeding.
... Although some detailed studies are available, they have focused on a small number of taxa and tend to be published in older literature sources and/or in languages other than English. Research has prioritized the venom systems of potentially dangerous species such as black widows (Latrodectus spp.), brown spiders (Loxosceles spp.) and wandering spiders (Phoneutria spp.) [13][14][15][16][17][18]. More recent studies have considered lynx spiders (Oxyopidae), wolf spiders (Lycosa spp.), furrow orb-weavers (Larinioides spp.), tarantulas (Vitalius spp.) and tube web spiders (Segestria spp.) among others [19][20][21][22][23][24][25][26]. ...
... More recent studies have considered lynx spiders (Oxyopidae), wolf spiders (Lycosa spp.), furrow orb-weavers (Larinioides spp.), tarantulas (Vitalius spp.) and tube web spiders (Segestria spp.) among others [19][20][21][22][23][24][25][26]. The previous works distinguish three principal units into which the venom system of spiders can be divided [13][14][15][16][17][18][19][20][21][22][23][24][25][26]. The first is presented by the two chelicerae, which serve as the injectors of the system. ...
... After several components are synthesized and the cytoplasm is enriched in products, the cell membrane ruptures and releases its contents into the venom gland. Although being a rather destructive mode of secretion, holocrine mechanisms have been reported for several spider venom systems [6,13,14,50]. As it is also encountered in scorpions, holocrine secretion may play a general role in arachnids [51]. ...
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 (Argiope bruennichi) 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.
... The venom gland is surrounded by muscular layers controlling venom release by squeezing the venom gland [54]. Depending on the spider species, venom is released into the glandular lumen by disintegration of entire cells (holocrine secretion) or by pinch off of parts of cells to form extracellular membrane-bound vesicles and release of venom components from these vesicles (apocrine secretion) [54][55][56]. ...
This review gives an overview on the development of research on spider venoms with a focus on structure and function of venom components and techniques of analysis. Major venom component groups are small molecular mass compounds, antimicrobial (also called cytolytic, or cationic) peptides (only in some spider families), cysteine-rich (neurotoxic) peptides, and enzymes and proteins. Cysteine-rich peptides are reviewed with respect to various structural motifs, their targets (ion channels, membrane receptors), nomenclature, and molecular binding. We further describe the latest findings concerning the maturation of antimicrobial, and cysteine-rich peptides that are in most known cases expressed as propeptide-containing precursors. Today, venom research, increasingly employs transcriptomic and mass spectrometric techniques. Pros and cons of venom gland transcriptome analysis with Sanger, 454, and Illumina sequencing are discussed and an overview on so far published transcriptome studies is given. In this respect, we also discuss the only recently described cross contamination arising from multiplexing in Illumina sequencing and its possible impacts on venom studies. High throughput mass spectrometric analysis of venom proteomes (bottom-up, top-down) are reviewed.
... However, few advances have been achieved in the study of the venom-producing apparatus. Although morphological and histological aspects of P. nigriventer venom glands were described in pioneering studies in Brazil (Bücherl, 1964(Bücherl, , 1972Schenberg and Pereira-Lima, 1978;Vital-Brazil andVellard, 1925 as cited in Bücherl, 1964), the microanatomy and ultrastructure were studied much later, using more current technologies (Silva et al., 2008). External and internal features of the ampoule-shaped venom gland were detailed through several methods including differential interference contrast, scanning electron microscopy and laser confocal scanning microscopy. ...
... Secretory vesicles in P. nigriventer venom gland were shown to contain granules with heterogenous staining patterns in histological sections and also distinct electron densities when observed under transmission electron microscopy. These findings lead to two hypotheses regarding the venom composition: (1) individual cell types within the gland produce different compounds that are mixed in the glandular lumen, or (2) the venom gland is composed of secretory cells containing granules in different stages of maturation (Silva et al., 2008). In the present study, we aimed at visualizing P. nigriventer toxins and toxin-secretory cells in situ. ...
... Then, they were dehydrated with increasing concentrations of ethanol (60, 70, 80 and 95%) for 15 min each. After embedding in historesin (Leica, Microsystems Nussloch/Heidelberg) overnight at 4°C and polymerization at room temperature, 2 μm sections were cut using a microtome (Micron HM 340 E) and allowed to dry and attach to glass slides (Silva et al., 2008). ...
In the last decades, main advances were achieved in the identification, structural and pharmacological characterization of Phoneutria nigriventer toxins. However, studies on the venom-producing apparatus are rare. Presently, we applied immunolabeling to historesin-embedded cross-sections of P. nigriventer venom glands. Toxins and toxin-secreting cells were successfully located in situ, using laser confocal scanning microscopy. The methodological strategy was successful and may be applied in future studies on venom glands and other secreting tissues, in general.
... The samples were dehydrated with increasing concentrations of ethanol (30–100%) for 30 min each, followed by embedding in historesin (Leica, Microsystems Nussloch/Heidelberg) overnight and polymerization at room temperature as described by the product protocol. Thin slices of 1 µm were sectioned randomly at different angles using a histological microtome (Micron HM 340 E) (Walldorf, Germany) and placed over warmed glass slides for staining with 1% toluidine blue [20]. The historesin resin enables 1-µm thick sections to be obtained instead of the usual 5-µm paraffin sections, providing better tissue detail and definition. ...
Schistosomiasis is a parasitic disease that is highly prevalent, especially in developing countries. Biomphalaria tenagophila is an important invertebrate host of Schistosoma mansoni in Brazil, with some strains (e.g. Cabo Frio) being highly susceptible to the parasite, whereas others (e.g. Taim) are completely resistant to infection. Therefore, B. tenagophila is an important research model for studying immune defense mechanisms against S. mansoni. The internal defense system (IDS) of the snail comprises hemocytes and hemolymph factors acting together to recognize self from non-self molecular patterns to eliminate the threat of infection. We performed experiments to understand the cellular defenses related to the resistance and/or susceptibility of B. tenagophila to S. mansoni. During the early stages of infection, fibrous host cells of both snail strains were arranged as a thin layer surrounding the sporocysts. However, at later stages of infection, the cellular reactions in resistant snails were increasingly more intense, with thicker layers surrounding the parasites, in contrast to susceptible strains. All parasites were damaged or destroyed inside resistant snails after 10 h of infection. By contrast, parasites inside susceptible snails appeared to be morphologically healthy. We also performed experiments using isolated hemocytes from the two strains interacting with sporocysts. Hemocyte attachment started as early as 1 h after initial infection in both strains, but the killing of sporocysts was exclusive to hemocytes from the resistant strain and was time course dependent. The resistant strain was able to kill all sporocysts. In conclusion, our study revealed important aspects of the initial process of infection related to immune defense responses of strains of B. tenagophila that were resistant to S. mansoni compared with strains that were susceptible. Such information is relevant for the survival or death of the parasites and so is important in the development of control measures against this parasite.
