Mechanisms of nodule-specific melanization in the hemocoel of the silkworm, Bombyx mori

Shi, Min; Mang, Dingze; Fu, Gege Sun; Tanaka, Shiho; Endo, Haruka; Kikuta, Shingo; Satō, Ryōichi

doi:10.1016/j.ibmb.2015.12.005

Cited by 20 publications

(19 citation statements)

References 48 publications

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“…Hemolymph melanization is a conserved immune response in insects and other arthropods [5,6], and is involved in many molecular and/or biochemical reactions, such as serine protease cascade, prophenoloxidase cascade, lozenge, lipopolysaccharide-binding protein and reeler, etc. [7,8,9,10,11,12,13,14,15]. However, the knowledge of the physiological process of hemolymph circulatory system, which contains various complex reactions to immune melanization, is lacking.…”

Section: Introductionmentioning

confidence: 99%

Hemocyte Changes During Immune Melanization in Bombyx Mori Infected with Escherichia coli

Yan

Wang

et al. 2019

Insects

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Hemolymph melanization is a conserved immune response in insects and other arthropods. However, the physiological process of the hemolymph system in the melanization response is hardly studied. Here, alterations of hemocytes in immune melanization were observed by Escherichia coli infection in Bombyx mori. Results first showed that there were cells aggregating into clusters. However, it vanished, and only part of clustered hemocytes were melanized during the period of intense immunity. The hemocyte numbers immediately decreased following an immune challenge, slowly increased to a peak, then reduced and finally returned to normalization. Granulocytes participated in cells aggregation at the early and later immune stage, while plasmatocytes were responsible for hemocytes agglomerate and melanization for the longest time, and more oenocytoids appeared at the peak stage of melanization. Moreover, hemocytes played a crucial role in resisting invasion of pathogens by agglomerate and melanization, and the circulatory system maintained higher hemocyte numbers and stronger antibacterial activity in fifth than fourth instar larvae after infection. In vitro immune melanization was most likely preferentially implemented in an independent process. These were the main characteristics reflecting the physiological process of hemolymph immune melanization, which provided an important foundation for further study of the complete mechanisms in the immunity of silkworm.

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Section: Introductionmentioning

confidence: 99%

Hemocyte Changes During Immune Melanization in Bombyx Mori Infected with Escherichia coli

Yan

Wang

et al. 2019

Insects

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“…The silkworm, one of the best models, is an ideal choice for viral research and contributes significantly to the study of insect immunity. In recent years, with the development and progression of modern genetics, cell biology, molecular biology, proteomics, systems biology and other new technologies, a large amount of data and findings have accumulated with respect to this area (Wan et al, ; Wang et al, ; Shu et al, ). There are three main effector systems in insects, namely AMPs, phenoloxidase‐dependent melanization and apoptosis‐associated genes, all of which are critical (Lü, ).…”

Section: Introductionmentioning

confidence: 99%

Research progress on the immune mechanism of the silkworm Bombyx mori

et al. 2018

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The silkworm Bombyx mori L., representing an important economic insect and one of the best models for studying insect immunity, possesses an efficient and sophisticated innate immune system against invasive microorganisms. The innate immune system basically includes humoural immunity and cellular immunity. The humoural immunity, which functions via molecules including humoural factors, lysozymes, phenoloxidase, hemolin, lectins and, in particular, antimicrobial peptides, plays a central role in eliminating the invading pathogens. The cellular immunity is primarily carried out and mediated by plasmatocytes and granular cells of haemocytes in the haemolymph, usually followed by melanization. Additionally, apoptosis, a primary viral defence for insects lacking adaptive immunity, comprises an important part of the silkworm immune system. Currently, there is still the lack of a comprehensive and systematic understanding of the molecular mechanisms of silkworm immunity. We review the latest research progress on silkworm immune mechanisms, including phenoloxidase‐dependent melanization and apoptosis, which is conducive to improving our understanding of the silkworm immune mechanism, clarifying the relationship of various immune mechanisms, and also providing a theoretical basis and reference for the future research of insect immunity.

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“…Lectins bind not only to PAMPs, but also to hemocytes, and trigger cellular immunity [29,31], including pattern recognition, nodule formation, encapsulation, melanization, phagocytosis, and proPO activation [32][33][34]. The pathogens were encapsulated by multiple layers of hemocytes [27,29].…”

Section: Discussionmentioning

confidence: 99%

Five Silkworm 30K Proteins Are Involved in the Cellular Immunity against Fungi

Dong

Guo

et al. 2021

Insects

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Background: 30K proteins are a major group of nutrient storage proteins in the silkworm hemolymph. Previous studies have shown that 30K proteins are involved in the anti-fungal immunity; however, the molecular mechanism involved in this immunity remains unclear. Methods: We investigated the transcriptional expression of five 30K proteins, including BmLP1, BmLP2, BmLP3, BmLP4, and BmLP7. The five recombinant 30K proteins were expressed in an Escherichia coli expression system, and used for binding assays with fungal cells and hemocytes. Results: The transcriptional expression showed that the five 30K proteins were significantly upregulated after injection of pathogen-associated molecular patterns to the fifth instar larvae, indicating the possibility of their involvement in immune response. The binding assay showed that only BmLP1 and BmLP4 can bind to both fungal cells and silkworm hemocytes. Furthermore, we found that BmLP1-coated and BmLP4-coated agarose beads promote encapsulation of hemocytes in vitro. The hemocyte encapsulation was blocked when the BmLP1-coated beads were preincubated with BmLP1 specific polyclonal antibodies. Conclusions: These results demonstrate that 30K proteins are involved in the cellular immunity of silkworms by acting as pattern recognition molecules to directly recruit hemocytes to the fungal surface.

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Mechanisms of nodule-specific melanization in the hemocoel of the silkworm, Bombyx mori

Cited by 20 publications

References 48 publications

Hemocyte Changes During Immune Melanization in Bombyx Mori Infected with Escherichia coli

Hemocyte Changes During Immune Melanization in Bombyx Mori Infected with Escherichia coli

Research progress on the immune mechanism of the silkworm Bombyx mori

Five Silkworm 30K Proteins Are Involved in the Cellular Immunity against Fungi

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