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Host Defense and Parasite Evasion
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
Tsetse flies such as Glossina morsitans that serve as vectors of African trypanosomes harbor a number of different specialized obligatory bacterial symbionts, some that can play a protective role. One such symbiont, Wigglesworthia glossinidia (Figure 4.11), provides vitamins that are otherwise not available in the exclusively blood-derived diet of tsetse flies. In addition, if flies are denied access to W. glossinidia during their larval development, they will be both sterile and immunocompromised. They are vulnerable to infections with Escherichia coli and exhibit reduced expression of genes that encode antimicrobial peptides (cecropin and attacin), other hemocyte-derived proteins (thioester-containing proteins 2 and 4 and prophenoloxidase) and signal-mediating molecules. Furthermore, they have reduced hemocyte populations, and they become more susceptible to trypanosome infections. This evidence indicates that W. glossinidia must be present if the tsetse immune system is to develop properly. Studies of the human microbiome (the collection of microorganisms that normally reside in or on the body) reveal a similar trend: full immune maturation depends on the presence and stimulation provided by human microbial symbionts.
Comparative Immunology
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
All animals, regardless of their evolutionary complexity require protection against microbial invasion, in general, invertebrates rely exclusively on innate immune mechanisms. Vertebrates, in contrast, use both innate and specific adaptive immune mechanisms. Thus typical invertebrates such as insects possess a complex mixture of lectins that can bind to microbial carbohydrates, opsonize them, and promote destruction by aggressive phagocytic cells. This is enhanced by an effective inflammatory response and the prophenoloxidase pathway. More advanced invertebrates such as the chordates, while relying on innate immunity, show evidence of the appearance of precursors of the specific adaptive immune system.
Host Defense and Parasite Evasion
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2015
Eric S. Loker, Bruce V. Hofkin
The two examples noted above are mutualistic partnerships that infect and overcome invertebrate host defenses, but invertebrate hosts can play the symbiont game too, enlisting them to augment their defenses against parasite attack. By their possession of the symbiotic bacterium Hamiltonella defensa, which produces compounds that suppress wasp development, pea aphids (Acyrthosiphon pisum) are protected from attack by the parasitoid wasp Aphidius ervi. A further layer of intrigue exists in this case because the factors that prevent wasp development are actually toxins encoded in genes found in a bacteriophage that infects H. defensa. Tsetse flies such as Glossina morsitans that serve as vectors of African trypanosomes harbor a number of different specialized obligatory bacterial symbionts, some that can play a protective role. One such symbiont, Wigglesworthia glossinidia (Figure 4.8), provides vitamins that are not otherwise available in the exclusively blood-derived diet of tsetse flies. In addition, if flies are denied access to W. glossinidia during their development, they are both sterile and immunocompromised. They are vulnerable to infections with Escherichia coli and exhibit reduced expression of genes that encode antimicrobial peptides (cecropin and atta-cin), other hemocyte-derived proteins (thioester-containing proteins 2 and 4 and prophenoloxidase), and signal-mediating molecules. Furthermore, they have reduced hemocyte populations, and they become more susceptible to trypanosome infections. This evidence indicates that W. glossinidia must be present if the tsetse immune system is to develop properly. Studies of the human microbiome (the collection of microorganisms that normally reside in or on the body) reveal a similar trend: full immune maturation depends on the presence and stimulation provided by human microbial symbionts. In the case of the tsetse flies, there are also some indications that other species of bacterial symbionts can also provide nutrients such as phenylalanine needed for trypanosome development and so may actually favor development of trypanosome infections in some species of Glossina.
Cloning and Analysis of the Multiple Transcriptomes of Serine Protease Homologs in Crayfish (Procambarus clarkii)
Published in Immunological Investigations, 2019
Crayfish, like other crustaceans, lacks a true adaptive immune response system. However, living in an aquatic environment rich in microorganisms, such as bacteria, fungi, and viruses, crayfish has developed effective mechanisms that depend entirely on innate immune response system for detecting and eliminating pathogen. The prophenoloxidase-activating system (proPO system) is one of the important innate immune response systems in crustacean. It participates in the innate immune response through melanization, cytotoxicreactions, cell adhesion capsulation, and phagocytosis (Cerenius and Söderhäll, 2004; Jiravanichpaisal et al., 2006; Lee and Söderhäll, 2002).
Identification of novel adhesive proteins in pearl oyster by proteomic and bioinformatic analysis
Published in Biofouling, 2021
The proteomic data on pearl oyster byssus adhesives provide an opportunity to compare different adhesive systems such as the adhesives of mussels, tubeworms, and barnacles. In barnacle adhesives, proteins related to the prophenoloxidase system, tyrosinase, peroxidases, protease inhibitor (e.g. serine protease), C-type lectin, spondin-1, von Willebrand factor type D domain containing proteins, and extracellular matrix proteins (annexinB-10 and cartilage oligomeric matrix protein) have been reported (Essock-Burns et al. 2019; Schultzhaus et al. 2020) in addition to structural bulk adhesive proteins such as settlement-inducing protein complex and cement proteins (Liang et al. 2019). In sandcastle worm adhesives, phosphorylated serine and DOPA dominated proteins, along with histidine and lysine-rich proteins make up the structural components (Stewart et al. 2011). However, proteomic analysis of this system is lacking although a cDNA library from the adhesive gland of sandworm showed the presence of tyrosinase and laccase (Endrizzi and Stewart 2009). In mussel adhesives, the most studied adhesive system, DOPA-rich and cysteine-rich proteins (mussel foot protein 1-6) are found to be the key players (Nicklisch and Waite 2012; Waite 2017). In addition to these structural proteins, tyrosinase, superoxide dismutase, peroxidase, collagen-like proteins, thioester-containing proteins, and C1q domain containing proteins are also found (Qin et al. 2016). In summary, it seems that although different adhesive systems have diverse structural proteins, shared proteins do exist such as tyrosinase, peroxidases, and protease inhibitors which are related to the modification of structural proteins. Interestingly, the common proteins found in diverse adhesive systems may suggest a common adhesion mechanism from the point of view of polymerization, which involves the modification of proteins into insoluble network materials. Similar concepts have been proposed before in the barnacle adhesive system (Dickinson et al. 2009). These findings merit further examination that might be beneficial for understanding the evolution of bioadhesives, inspiring biomimetic synthesis of adhesives for underwater use, and developing solutions for combating biofouling. For instance, chemicals that inhibit the activity of tyrosinase, peroxidases, and protease inhibitors might be useful for biofouling control.