Applying the silkworm model for the search of immunosuppressants

Miyashita, Atsushi; Hamamoto, Hiroshi; Sekimizu, Kazuhisa

doi:10.5582/ddt.2021.01041

Cited by 7 publications

(3 citation statements)

References 18 publications

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“…4). In our laboratory, we are developing experimental systems using invertebrates such as silkworms for applications in drug discovery screening (16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26). However, merely accelerating the assay systems is not sufficient; it is only by constructing a library with high diversity that we can truly enhance the output, that is, exploratory drug discovery research.…”

Section: Discussionmentioning

confidence: 99%

Advancing microbial isolation: The impact of leaf mold extract agar on soil samples

Miyashita,

Mikami,

Ishii

et al. 2024

Preprint

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In this study, we developed a new agar medium using leaf mold extract and evaluated its microbial cultivation performance with soil samples. As a control for performance evaluation, the general-purpose nutrient medium YME agar was used. For YME agar, isolated microbes were confirmed to belong mainly to the Bacillus genus through 16S rRNA gene sequencing. In contrast, for the leaf mold agar, bacteria belonging to either Streptomyces or Rhizobium were frequently isolated. Also, of the 51 sequenced isolates on the leaf mold agar medium, an unidentified species (i.e., not listed in databases) with 16S rRNA sequence identity below 98.7% was found. The unidentified species did not grow in standard nutrient media (YME, BHI, LB10, or TSB) but grew in 10% leaf mold extract. The findings of this study suggest that the use of leaf mold agar medium can effectively isolate soil microbes that are difficult to culture in general-purpose nutrient media such as YME. Moreover, this approach indicates a viable method for discovering unknown, previously-uncultured microbial species from soil samples.

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Section: Discussionmentioning

confidence: 99%

Advancing microbial isolation: The impact of leaf mold extract agar on soil samples

Miyashita,

Mikami,

Ishii

et al. 2024

Preprint

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“…The phenoloxidases (PPO1 and PPO2)-deficient flies are sensitive to Staphylococcus aureus infection [ 28 ]. Therefore, hemolymph melanization in insects can be used as an indicator of innate immune system activation [ 17 , 19 , 29 ]. The induction of innate immunity by Porphyromonas gingivalis and Candida albicans was evaluated by silkworm hemolymph melanization [ 24 , 30 ].…”

Section: Introductionmentioning

confidence: 99%

Acute melanization of silkworm hemolymph by peptidoglycans of the human commensal bacterium Cutibacterium acnes

2022

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Cutibacterium acnes is a pathogenic bacterium that cause inflammatory diseases of the skin and intervertebral discs. The immune activation induced by C. acnes requires multiple cellular responses in the host. Silkworm, an invertebrate, generates melanin by phenoloxidase upon recognizing bacterial or fungal components. Therefore, the melanization reaction can be used as an indicator of innate immune activation. A silkworm infection model was developed for evaluating the virulence of C. acnes, but a system for evaluating the induction of innate immunity by C. acnes using melanization as an indicator has not yet been established. Here we demonstrated that C. acnes rapidly causes melanization of the silkworm hemolymph. On the other hand, Staphylococcus aureus, a gram-positive bacterium identical to C. acnes, does not cause immediate melanization. Even injection of heat-killed C. acnes cells caused melanization of the silkworm hemolymph. DNase, RNase, and protease treatment of the heat-treated C. acnes cells did not decrease the silkworm hemolymph melanization. Treatment with peptidoglycan-degrading enzymes, such as lysostaphin and lysozyme, however, decreased the induction of melanization by the heat-treated C. acnes cells. These findings suggest that silkworm hemolymph melanization may be a useful indicator to evaluate innate immune activation by C. acnes and that C. acnes peptidoglycans are involved in the induction of innate immunity in silkworms.

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“…The hemolymph melanization and Toll pathway-dependent immune responses are mediated by the same recognition steps through pattern recognition receptors and cofactors [25][26][27]. Therefore, hemolymph melanization in silkworms can be used as an indicator of innate immune system activation [17,19,28]. The induction of innate immunity by Porphyromonas gingivalis and Candida albicans was evaluated by silkworm hemolymph melanization [24,29].…”

Section: Introductionmentioning

confidence: 99%

Acute innate immune activation in silkworm by the human commensal bacterium Cutibacterium acnes

Matsumoto

Sato

Sugita

2022

Preprint

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Cutibacterium acnes is a pathogenic bacterium that cause inflammatory diseases of the skin and intervertebral discs. The immune activation induced by C. acnes requires multiple cellular responses in the host. Silkworm, an invertebrate, generates melanin by phenoloxidase upon recognizing bacterial or fungal components. Therefore, the melanization reaction can be used as an indicator of innate immune activation. A silkworm infection model was developed for evaluating the virulence of C. acnes, but a system for evaluating the induction of innate immunity by C. acnes using melanization as an indicator has not yet been established. Here we demonstrated that C. acnes rapidly causes melanization of the silkworm hemolymph within 3 h. On the other hand, Staphylococcus aureus, a gram-positive bacterium identical to C. acnes, does not cause immediate melanization. Even injection of heat-killed C. acnes cells caused melanization of the silkworm hemolymph. DNase, RNase, and protease treatment of the heat-treated C. acnes cells did not decrease the silkworm hemolymph melanization. Treatment with peptidoglycan-degrading enzymes, such as lysostaphin and lysozyme, however, decreased the induction of melanization by the heat-treated C. acnes cells. These findings suggest that silkworm hemolymph melanization may be a useful indicator to evaluate innate immune activation by C. acnes and that C. acnes peptidoglycans are involved in the induction of innate immunity in silkworms.

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Applying the silkworm model for the search of immunosuppressants

Cited by 7 publications

References 18 publications

Advancing microbial isolation: The impact of leaf mold extract agar on soil samples

Advancing microbial isolation: The impact of leaf mold extract agar on soil samples

Acute melanization of silkworm hemolymph by peptidoglycans of the human commensal bacterium Cutibacterium acnes

Acute innate immune activation in silkworm by the human commensal bacterium Cutibacterium acnes

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