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Phylogeny of the mucosal immune system
Published in Phillip D. Smith, Richard S. Blumberg, Thomas T. MacDonald, Principles of Mucosal Immunology, 2020
Robert D. Miller, Irene Salinas
With regard to the mucosal immune system, invertebrates continue to shed light on the conserved interactions between the microbiota and the intestinal immune system. The gut of most invertebrates is lined by the peritrophic matrix, which is composed by chitin fibrils and glycoproteins and physically excludes the gut epithelium from external abrasions and is analogous to the mammalian mucus layer. Both insects and prochordates like the sea squirt Ciona intestinalis, produce chitin binding proteins in their gut. C. intestinalis, in turn, produces variable chitin binding proteins (VCBPs). VCBPs contain an immunoglobulin-like domain, bind chitin fibrils, and facilitate phagocytosis of bacteria.
Mite allergens
Published in Richard F. Lockey, Dennis K. Ledford, Allergens and Allergen Immunotherapy, 2020
Enrique Fernández-Caldas, Leonardo Puerta, Luis Caraballo, Victor Iraola, Richard F. Lockey
Der p 23 has sequence homology to peritrophins, which contain chitin-binding domains and is part of the peritrophic matrix lining the gut of arthropods. Recombinant Der p 23 reacted with IgE antibodies from 74% of D. pteronyssinus-allergic patients (n = 347) at levels comparable to the two major HDM allergens, Der p 1 and Der p 2, and exhibits high allergenic activity as demonstrated by upregulation of CD203c expression on basophils from D. pteronyssinus-allergic patients. Immunogold electron microscopy localized the allergen in the peritrophic matrix lining the midgut of D. pteronyssinus as well as on the surface of the fecal pellets. The high allergenic activity of Der p 23 and its frequent recognition as a respiratory allergen may be explained by the fact that it becomes airborne and respirable through its association with mite feces [129]. Fifty-four percent of Thai HDM-allergic patients displayed Der p 23–specific IgE responses, and rDer p 23 was able to induce basophil degranulation of rat basophil leukemia cells [130].
The malaria parasites
Published in David A Warrell, Herbert M Gilles, Essential Malariology, 2017
Robert E Sinden, Herbert M Gilles
The ookinete traverses the chitinous peritrophic matrix, which it is believed is laid down by the mosquito as a defence against infection. The ookinete does this by secreting a prochitinase enzyme that is subsequently activated in the gut by proteolysis. The ookinete subsequently interacts with the complex microvillar surface of the mid-gut wall, where it appears glycosylated molecules may be important receptors. Invasion of the mid-gut wall requires the expression of a secretory protein – circumsporozoite, thrombospondin-related protein (CTRP) – but is not dependent upon the expression of major surface proteins P25 and P28. The ookinete reportedly invades only a subset of epithelial cells that express v-ATPase, though evidence for this is not yet conclusive. Within the cytoplasm of the epithelial cell, the ookinete appears to provoke the innate immune response of the mosquito, resulting in the expression of a wide range of immune peptides, e.g. Gram-negative binding protein, defension, and reactive molecules such as nitric oxide. A fraction of the ookinetes emerge through the basal plasma membrane of the mid-gut cell and ‘bump into’ the collagenous basal lamina. Here, the ookinete comes to rest and initiates its differentiation into an oocyst. It is now some 24–36 hours since the mosquito took its blood feed.
Azadirachtin-based biopesticide affects the respiration and digestion in Anticarsia gemmatalis caterpillars
Published in Toxin Reviews, 2022
Cliver Fernandes Farder-Gomes, Meenakshi Saravanan, Luis Carlos Martínez, Angelica Plata-Rueda, José Cola Zanuncio, José Eduardo Serrão
In the control, the midgut epithelium of A. gemmatalis had a single layer of the digestive, goblet, and regenerative cells (Figure 4(A)). Digestive cells showed homogeneous cytoplasm, a well-developed nucleus rich in decondensed chromatin, and a well-developed brush border on the apical surface (Figure 4(A)). Goblet cells were characterized by a large cavity with a brush border (Figure 4(A)). In these caterpillars, the midgut lumen had an evident peritrophic matrix enveloping the food (Figure 4(A)). After 3 h feeding on a diet with azadirachtin LC50, the midgut had digestive cells with some cytoplasm vacuolization and disorganization of the brush border that also occurred in the cavity of goblet cells (Figure 4(B)). After 6 h of exposure to azadirachtin, the midgut showed some digestive cells with apical protrusions and the nucleus with condensed chromatin and disorganized peritrophic matrix (Figure 4(C)). The increase in cytoplasm vacuolization and apical protrusions in addition to the release of cell fragments, some with the cell nucleus, to the midgut lumen of A. gemmatalis occurred after 12 and 24 h of exposure to azadirachtin (Figure 4(D,E)). During these periods of exposure, goblet cells also showed vacuolization and severe disorganization of the brush border (Figure 4(E)) and the peritrophic matrix remained disorganized (Figure 4(E)).
Insecticide potential of two saliva components of the predatory bug Podisus nigrispinus (Heteroptera: Pentatomidae) against Spodoptera frugiperda (Lepidoptera: Noctuidae) caterpillars
Published in Toxin Reviews, 2022
Juliana Mendonça Campos, Luis Carlos Martínez, Angelica Plata-Rueda, Wolfgang Weigand, José Cola Zanuncio, José Eduardo Serrão
The fat body of the control S. frugiperda caterpillars had well-developed globular cells with cytoplasm rich in granules and irregular nucleus (Figure 1). The muscle cells had striated cytoplasm and multiple nuclei (Figure 1). In the midgut, the digestive cells had apical surface with well-developed brush border and cytoplasm with some vacuoles (Figure 1). The goblet cells had regular cavity, homogeneous cytoplasm, and basal nucleus (Figure 1). The peritrophic matrix was characterized by regular layers in the midgut lumen (Figure 1).