1
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Hamamoto H. Silkworm model of bacterial infection facilitates the identification of lysocin E, a potent, ultra-rapid bactericidal antibiotic. J Antibiot (Tokyo) 2024; 77:477-485. [PMID: 38773231 DOI: 10.1038/s41429-024-00739-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 04/22/2024] [Accepted: 04/25/2024] [Indexed: 05/23/2024]
Abstract
The development of novel antimicrobial agents is required to solve the problem of antimicrobial resistance. We established a quantitative method for evaluating the therapeutic efficacy of antimicrobial agents in a silkworm bacterial infection model. Pharmacokinetic factors are present in the silkworm as well as in mice, and evaluating the therapeutic efficacy of antimicrobial agents is possible in a silkworm infection model, comparable to that in a mammalian model. This silkworm model was used to screen for novel antimicrobial agents with therapeutic efficacy as an indicator. As a result, a new antibiotic, lysocin E, was discovered. Lysocin E has a completely different mechanism of action from existing antimicrobial agents, and its potent bactericidal activity leads to remarkable therapeutic efficacy in a mouse model. In this review, I describe the features of the silkworm model that have contributed to the discovery of lysocin E and its mechanisms of action.
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Affiliation(s)
- Hiroshi Hamamoto
- Yamagata University Faculty of Medicine, 2-2-2 Iida-Nishi, Yamagata, 990-9585, Japan.
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2
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Miyashita A, Miyauchi M, Tabuchi F. The prospects of automation in drug discovery research using silkworms. Drug Discov Ther 2024; 18:130-133. [PMID: 38569832 DOI: 10.5582/ddt.2024.01013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2024]
Abstract
We have established several models of infectious diseases in silkworms to explore disease-causing mechanisms and identify new antimicrobial substances. These models involve injecting laboratory-cultured pathogens into silkworms and monitoring their survival over a period of days. The use of silkworms is advantageous because they are cost-effective and raise fewer ethical concerns than mammalian subjects, allowing for larger experimental group sizes. To capitalize on these benefits, there is a growing importance in mechanizing and automating the experimental processes that currently require manual labor. This paper discusses the future of laboratory automation, specifically through the mechanization and automation of silkworm-based experimental procedures.
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Affiliation(s)
| | | | - Fumiaki Tabuchi
- Teikyo University Institute of Medical Mycology, Tokyo, Japan
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3
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Hossain MI, Saleh NUA, Numan A, Hossain MM, Uddin MA, Hossain MS. Bombyx mori as a model for Niallia circulans pathogenicity. Drug Discov Ther 2023; 17:18-25. [PMID: 36843035 DOI: 10.5582/ddt.2022.01112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Abstract
Increasing incidences of resistance to antibiotics by pathogenic bacteria is a worldwide concern and isolation of antibiotic-resistant strains of Niallia circulans (formerly known as Bacillus circulans), an opportunistic human pathogen, has been reported. Due to their lack of ethical constraints as well as their cost-effective rearing, invertebrates have been commonly used to study infection by bacteria pathogenic to humans. In this study, we demonstrate that a foodborne strain of N. circulans kills larvae of the silkworm, Bombyx mori within 48 h after hemolymph injection. The infected larvae turned black with an increase in the phenoloxidase (PO) activity in the hemolymph. Midgut injection of N. circulans resulted in the killing of larvae within 96 h. A significant increase in bacterial load was observed in the hemolymph 12 h after infection. The viable hemocyte number decreased to 48% within 12 h of injection. RT-qPCR analysis revealed that upon hemolymph infection with N. circulans the expression of the antimicrobial peptide (AMP) genes, Bmdefensin-B and Bmgloverin-3, were upregulated 2.5- and 1.8-fold, respectively, whereas 1.6-fold upregulation was observed for BmToll-2 in the larval fat body. Therapeutic effects of antibiotics like tetracycline, imipenem, ceftriaxone, ampicillin, and clindamycin were observed against N. circulans in the Bombyx larvae with varying efficacies. Results from this study suggest that larvae of B. mori can be used as infection models for screening therapeutics that are effective against N. circulans.
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Affiliation(s)
- M Ismail Hossain
- Department of Biochemistry and Microbiology, School of Health and Life Sciences, North South University, Dhaka, Bangladesh
| | - Nusrat U A Saleh
- Department of Biochemistry and Microbiology, School of Health and Life Sciences, North South University, Dhaka, Bangladesh
| | - Al Numan
- Department of Biochemistry and Microbiology, School of Health and Life Sciences, North South University, Dhaka, Bangladesh
| | - M Mahtab Hossain
- Department of Biochemistry and Microbiology, School of Health and Life Sciences, North South University, Dhaka, Bangladesh
| | - M Aftab Uddin
- Bangladesh Sericulture Research and Training Institute, Rajshahi, Bangladesh
| | - Muktadir S Hossain
- Department of Biochemistry and Microbiology, School of Health and Life Sciences, North South University, Dhaka, Bangladesh
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4
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Wang Q, Sun Z, Ma S, Liu X, Xia H, Chen K. Molecular mechanism and potential application of bacterial infection in the silkworm, Bombyx mori. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2022; 131:104381. [PMID: 35245606 DOI: 10.1016/j.dci.2022.104381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 02/14/2022] [Accepted: 02/27/2022] [Indexed: 06/14/2023]
Abstract
As a representative species of Lepidoptera, Bombyx mori has been widely studied and applied. However, bacterial infection has always been an important pathogen threatening the growth of silkworms. Bombyx mori can resist various pathogenic bacteria through their own physical barrier and innate immune system. However, compared with other insects, such as Drosophila melanogaster, research on the antibacterial mechanism of silkworms is still in its infancy. This review systematically summarized the routes of bacterial infection in silkworms, the antibacterial mechanism of silkworms after ingestion or wounding infection, and the intestinal bacteria and infection of silkworms. Finally, we will discuss silkworms as a model animal for studying bacterial infectious diseases and screening antibacterial drugs.
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Affiliation(s)
- Qiang Wang
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, PR China
| | - Zhonghe Sun
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, PR China
| | - Shangshang Ma
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, Jiangsu, PR China
| | - Xiaoyong Liu
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, PR China
| | - Hengchuan Xia
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, PR China
| | - Keping Chen
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, PR China.
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5
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Iwański B, Andrejko M. Host-pathogen interactions: The role of Pseudomonas aeruginosa exotoxin A in modulation of Galleria mellonella immune response. J Invertebr Pathol 2022; 187:107706. [PMID: 34919944 DOI: 10.1016/j.jip.2021.107706] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 12/07/2021] [Accepted: 12/10/2021] [Indexed: 10/19/2022]
Abstract
The role of Pseudomonas aeruginosa exotoxin A in the modulation of humoral immune response parameters in the hemolymph of Galleria mellonella larvae was investigated. Our results indicate that exoA can play a role of a virulence factor by inhibiting insect PO, lysozyme, and antibacterial activity and decreasing the apoLp-III protein level significantly. No peptide bands with molecular mass below 6.5 kDa were detected in the hemolymph of exoA-treated larvae. We provided evidence for involvement of exoA in the pathogenicity of P. aeruginosa against G. mellonella and the usefulness of the insect as a model for analysis of P. aeruginosa toxins.
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Affiliation(s)
- Bartłomiej Iwański
- Department of Immunobiology, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19 St., Lublin 20-033, Poland.
| | - Mariola Andrejko
- Department of Immunobiology, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19 St., Lublin 20-033, Poland
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6
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Ge Q, Cao W, Zhu F, Yuan Y, Chen L, Xu J, Li J, Chen H, Ma S, Sun L, Pan H, Taha RH, Yao Q, Chen K. Genomics and proteomics combined analysis revealed the toxicity response of silkworm Bombyx mori to the environmental pathogen Bacillus cereus ZJ-4. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 222:112467. [PMID: 34217115 DOI: 10.1016/j.ecoenv.2021.112467] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 06/13/2023]
Abstract
Bacterial contamination has caused a major public health problem worldwide. Bacillus cereus is a conditional environmental pathogenic bacteria that can cause food poisoning. Whether environmental pathogens can cause widespread transmission in the insect kingdom is unclear. In this study, a Bacillus cereus ZJ-4 was isolated from the hospital environment of Zhenjiang City, Jiangsu Province, China. It was fatal by injection into the silkworm hemolymph. To investigated the potential toxic factors of ZJ-4 and clarified the toxicity response mechanism of silkworm by the ZJ-4 infection. Then, the whole genome of ZJ-4 was sequenced, and the immune mechanism of silkworm fat body to ZJ-4 pathogen was studied by HE pathological section and proteomics. Bacterial genome sequencing indicated that ZJ-4 had 352 drug resistance genes and 6 virulence genes. After 36 h of subcutaneous puncture with ZJ-4 suspension, the pathological changes were obviously found in HE pathological sections of fat body tissue. Comparative proteomic results indicated that differentially expressed proteins are mainly involved in stress reactions, biological regulation, and innate immunity. The qRT-PCR analysis showed that the expressions of β-GRP, Spaetzle, MyD88, Tube and Dorsal genes in Toll pathway were up-regulated, while Pell and Cactus genes were down-regulated; in the antimicrobial peptide pathway, Glv2, Lzm, Mor, and Leb3 genes were up-regulated, while attacin1 and defensin genes were down-regulated; Sod gene was up-regulated, while Cat gene was down-regulated in the antioxidant pathway; Ldh, Sdh, and Mdh genes were down-regulated in glucose metabolism pathway. These results indicated that ZJ-4 can damage the innate immune pathway of silkworm, and also affect the normal immune function of fat body cells.
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Affiliation(s)
- Qi Ge
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, PR China; School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212013, PR China
| | - Weiping Cao
- The Fourth People's Hospital of Zhenjiang, Zhenjiang, Jiangsu 212001, PR China
| | - Feifei Zhu
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212013, PR China
| | - Yi Yuan
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212013, PR China; School of Food and Biological Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, PR China
| | - Liang Chen
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212013, PR China
| | - Jia Xu
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212013, PR China
| | - Jun Li
- Instrumental Analysis and Testing Center, Jiangsu University, Zhenjiang, Jiangsu 212013, PR China
| | - Han Chen
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212013, PR China
| | - Shangshang Ma
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212013, PR China; School of Food and Biological Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, PR China
| | - Lindan Sun
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212013, PR China
| | - Huiwen Pan
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212013, PR China; School of Food and Biological Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, PR China; Zhenjiang First People's Hospital, Zhenjiang, Jiangsu 212002, PR China
| | - Rehab Hosny Taha
- Plant Protection Research Institute, Agricultural Research Center, Egypt
| | - Qin Yao
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, PR China; School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212013, PR China
| | - Keping Chen
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212013, PR China.
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7
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Tagle-Olmedo T, Andrade-Pavón D, Martínez-Gamboa A, Gómez-García O, García-Sierra F, Hernández-Rodríguez C, Villa-Tanaca L. Inhibitors of DNA topoisomerases I and II applied to Candida dubliniensis reduce growth, viability, the generation of petite mutants and toxicity, while acting synergistically with fluconazole. FEMS Yeast Res 2021; 21:6219866. [PMID: 33837766 DOI: 10.1093/femsyr/foab023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 04/07/2021] [Indexed: 11/14/2022] Open
Abstract
The increasing resistance of Candida species to azoles emphasizes the urgent need for new antifungal agents with novel mechanisms of action. The aim of this study was to examine the effect of three DNA topoisomerase inhibitors of plant origin (camptothecin, etoposide and curcumin) on the growth of Candida dubliniensis. The phylogenetic analysis showed a close relationship between the topoisomerase enzymes of C. dubliniensis and Candida albicans. The alignment of the amino acid sequences of topoisomerase I and II of yeasts and humans evidenced conserved domains. The docking study revealed affinity of the test compounds for the active site of topoisomerase I and II in C. dubliniensis. Curcumin and camptothecin demonstrated a stronger in vitro antifungal effect than the reference drugs (fluconazole and itraconazole). Significant synergistic activity between the topoisomerase inhibitors and fluconazole at the highest concentration (750 µM) was observed. Fluconazole induced the petite phenotype to a greater degree than the topoisomerase inhibitors, indicating a tendency to generate resistance. Lower toxicity was found for such inhibitors versus reference drugs on Galleria mellonella larva. The topoisomerase inhibitors exhibited promising antifungal activity, and the DNA topoisomerase enzymes of C. dubliniensis proved to be an excellent model for evaluating new antifungal compounds.
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Affiliation(s)
- Tania Tagle-Olmedo
- Laboratorio de Biología Molecular de Bacterias y Levaduras, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prol. de Carpio y Plan de Ayala. Col. Sto. Tomás, 11340 México City, México
| | - Dulce Andrade-Pavón
- Laboratorio de Biología Molecular de Bacterias y Levaduras, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prol. de Carpio y Plan de Ayala. Col. Sto. Tomás, 11340 México City, México
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Av. Wilfrido Massieu S/N Unidad Profesional "Adolfo López Mateos", Zacatenco. Col. Lindavista, Venustiano Carranza, Del, CP 07700, D.F., México
| | - Areli Martínez-Gamboa
- Laboratorio de Microbiología Clínica, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, 15 Vasco de Quiroga Ave, Belisario Domínguez Sección XVI, Tlalpan, México City, Mexico
| | - Omar Gómez-García
- Departamento de Química Orgánica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prol. de Carpio y Plan de Ayala. Col. Sto. Tomás, 11340 México City, México
| | - Francisco García-Sierra
- Departamento de Biología Celular, Centro de investigación y estudios avanzados del Instituto Politécnico Nacional (CINVESTAV), México City, México
| | - César Hernández-Rodríguez
- Laboratorio de Biología Molecular de Bacterias y Levaduras, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prol. de Carpio y Plan de Ayala. Col. Sto. Tomás, 11340 México City, México
| | - Lourdes Villa-Tanaca
- Laboratorio de Biología Molecular de Bacterias y Levaduras, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prol. de Carpio y Plan de Ayala. Col. Sto. Tomás, 11340 México City, México
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8
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Kaito C, Murakami K, Imai L, Furuta K. Animal infection models using non-mammals. Microbiol Immunol 2020; 64:585-592. [PMID: 32757288 PMCID: PMC7590188 DOI: 10.1111/1348-0421.12834] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/17/2020] [Accepted: 07/27/2020] [Indexed: 12/31/2022]
Abstract
The use of non-human animal models for infection experiments is important for investigating the infectious processes of human pathogenic bacteria at the molecular level. Mammals, such as mice and rabbits, are also utilized as animal infection models, but large numbers of animals are needed for these experiments, which is costly, and fraught with ethical issues. Various non-mammalian animal infection models have been used to investigate the molecular mechanisms of various human pathogenic bacteria, including Staphylococcus aureus, Streptococcus pyogenes, and Pseudomonas aeruginosa. This review discusses the desirable characteristics of non-mammalian infection models and describes recent non-mammalian infection models that utilize Caenorhabditis elegans, silkworm, fruit fly, zebrafish, two-spotted cricket, hornworm, and waxworm.
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Affiliation(s)
- Chikara Kaito
- Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Kanade Murakami
- Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Lina Imai
- Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Kazuyuki Furuta
- Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama, Japan
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9
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Ahad II, Hossain MM, Uddin MA, Bari ML, Hossain MS. Therapeutic Effect of Antibiotics Against Escherichia coli O157:H7 in Silk Moth Larvae Animal Model. Curr Microbiol 2020; 77:2172-2180. [PMID: 32417963 DOI: 10.1007/s00284-020-02023-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 05/07/2020] [Indexed: 10/24/2022]
Abstract
The increasing clinical incidence of antibiotic resistance in bacteria is a major global health care issue. Rampant use of antimicrobials is one of the major reasons of the dramatic rise in antibiotic-resistant bacterial strains. Suitable animal models are required to improve our understanding of bacterial pathogenicity, evolution and search for novel antibiotics. The larvae of the silk moth (commonly called silkworm), Bombyx mori, have been used as an animal model for testing the pathogenicity of a clinically isolated strain of enterohemorrhagic Escherichia coli O157:H7 upon injection through hemolymph. Here, we show that a foodborne E. coli O157:H7 strain can kill silkworm larvae upon injection through either hemolymph (blood) or midgut. Bacterial number in the hemolymph started to increase after 3 h of injection into hemolymph, while the number of viable circulating hemocytes decreased. Administration of four well-known antibiotics into the larval hemolymph up to 100 µg per larva showed therapeutic effect with varying efficacies against E. coli O157:H7 with ceftriaxone and imipenem showing better effect. Our findings indicate that silkworm larvae can be used as an animal model to screen for novel antibiotics that are effective against E. coli O157:H7.
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Affiliation(s)
- Inteshar Ibn Ahad
- Department of Biochemistry and Microbiology, School of Health and Life Sciences, North South University, Bashundhara, Dhaka, 1229, Bangladesh
| | - M Mahtab Hossain
- Department of Biochemistry and Microbiology, School of Health and Life Sciences, North South University, Bashundhara, Dhaka, 1229, Bangladesh
| | - M Aftab Uddin
- Bangladesh Sericulture Research and Training Institute, Rajshahi, Bangladesh
| | - M Latiful Bari
- Center for Advanced Research in Sciences, University of Dhaka, Dhaka, Bangladesh
| | - Muktadir S Hossain
- Department of Biochemistry and Microbiology, School of Health and Life Sciences, North South University, Bashundhara, Dhaka, 1229, Bangladesh.
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10
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Oda M, Yokotani A, Hayashi N, Kamoshida G. Role of Sphingomyelinase in the Pathogenesis of Bacillus cereus Infection. Biol Pharm Bull 2020; 43:250-253. [DOI: 10.1248/bpb.b19-00762] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Masataka Oda
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University
| | - Atsushi Yokotani
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University
| | - Naoki Hayashi
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University
| | - Go Kamoshida
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University
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11
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Rossato JM, Moresco TR, Uczay J, da Rocha JBT. Staphylococcus aureus-induced sepsis in the lobster cockroach Nauphoeta cinerea. Comp Immunol Microbiol Infect Dis 2019; 66:101343. [PMID: 31446196 DOI: 10.1016/j.cimid.2019.101343] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 07/30/2019] [Accepted: 08/06/2019] [Indexed: 11/28/2022]
Abstract
Invertebrates have been instrumental in understanding the mechanisms involved in infectious diseases, considering the idea to replace, reduce and refine the use of mammals as well as to understand the basic principles of immune response in insect. We evaluated the consequences of Staphylococcus aureus-induced sepsis in the last instar nymphs of Nauphoeta cinerea injected with different concentrations of bacteria preserved in two culture media. Infected groups had a decrease in hemolymph metabolites (glucose, amino acids, total proteins, and cholesterol), in contrast to the proteins in the fat body. Higher concentrations of S. aureus caused permanent morphological alterations in adults, decrease in food consumption, increase in isolation, and increase in CFU until death of the cockroaches. Survival and protection of nymphs against a repeated and stronger challenge with the same bacteria varied according to the medium they were conserved. N. cinerea proves to be a suitable and promising model for studies related to bacterial infections.
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Affiliation(s)
- Juliana Marzari Rossato
- Departamento de Bioquímica e Biologia Molecular e Programa de Pós-graduação Bioquímica Toxicológica, Universidade Federal de Santa Maria (UFSM), Brazil.
| | - Terimar Ruoso Moresco
- Departamento de Ciências da Saúde, Laboratório de Microbiologia CEMICRO, UFSM, Brazil.
| | - Juliano Uczay
- Departamento de Ciências da Saúde, Laboratório de Microbiologia CEMICRO, UFSM, Brazil.
| | - João Batista Teixeira da Rocha
- Departamento de Bioquímica e Biologia Molecular e Programa de Pós-graduação Bioquímica Toxicológica, Universidade Federal de Santa Maria (UFSM), Brazil.
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12
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Matsumoto Y, Sekimizu K. Silkworm as an experimental animal for research on fungal infections. Microbiol Immunol 2019; 63:41-50. [PMID: 30666711 PMCID: PMC6594098 DOI: 10.1111/1348-0421.12668] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 01/04/2019] [Accepted: 01/13/2019] [Indexed: 12/26/2022]
Abstract
Silkworm, Bombyx mori, has various advantages as an experimental animal, such as the low cost for rearing and fewer ethical problems. Models utilizing silkworms of infection with pathogenic bacteria have been established for identification of genes encoding virulence factors by large-scale in vivo screening. In this review, we describe recent progress in the study of silkworm infection models for elucidating the mechanisms of fungi infection. Silkworm infection models have been established for Candida albicans, Candida tropicalis, Candida glabrata and Cryptococcus neoformans, which are yeast type fungi, and Aspergillus fumigatus, Arthroderma vanbreuseghemii, Arthroderma benhamiae, Microsporum canis, Trichophyton rubrum, and Rhizopus oryzae, which are filamentous fungi. Novel genes encoding virulence factors in C. albicans and C. glabrata have been identified by using the silkworm infection models. We here outline the benefits of using silkworm infection models and a strategy for identifying the genes responsible for pathogenicity of microorganisms such as fungi. © 2019 The Authors. Microbiology and Immunology Published by The Societies and John Wiley & Sons Australia, Ltd.
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Affiliation(s)
- Yasuhiko Matsumoto
- Teikyo University Institute of Medical Mycology359 OtsukaHachiojiTokyo 192‐0395Japan
| | - Kazuhisa Sekimizu
- Teikyo University Institute of Medical Mycology359 OtsukaHachiojiTokyo 192‐0395Japan
- Genome Pharmaceuticals Institute102 Next Building, 3‐24‐17 HongoBunkyo‐kuTokyo 113‐0033Japan
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13
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Panthee S, Paudel A, Hamamoto H, Sekimizu K. Advantages of the Silkworm As an Animal Model for Developing Novel Antimicrobial Agents. Front Microbiol 2017; 8:373. [PMID: 28326075 PMCID: PMC5339274 DOI: 10.3389/fmicb.2017.00373] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 02/23/2017] [Indexed: 11/13/2022] Open
Abstract
The demand for novel antibiotics to combat the global spread of multi drug-resistant pathogens continues to grow. Pathogenic bacteria and fungi that cause fatal human infections can also kill silkworms and the infected silkworms can be cured by the same antibiotics used to treat infections in the clinic. As an invertebrate model, silkworm model is characterized by its convenience, low cost, no ethical issues. The presence of conserved immune response and similar pharmacokinetics compared to mammals make silkworm infection model suitable to examine the therapeutic effectiveness of antimicrobial agents. Based on this, we utilized silkworm bacterial infection model to screen the therapeutic effectiveness of various microbial culture broths and successfully identified a therapeutically effective novel antibiotic, lysocin E, which has a novel mode of action of binding to menaquinone, thus leading to membrane damage and bactericidal activity. The similar approach to screen potential antibiotics resulted in the identification of other therapeutically effective novel antibiotics, such as nosokomycin and ASP2397 (VL-2397). In this regard, we propose that the silkworm antibiotic screening model is very effective for identifying novel antibiotics. In this review, we summarize the advantages of the silkworm model and propose that the utilization of silkworm infection model will facilitate the discovery of novel therapeutically effective antimicrobial agents.
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Affiliation(s)
- Suresh Panthee
- Institute of Medical Mycology, Teikyo University Tokyo, Japan
| | - Atmika Paudel
- Institute of Medical Mycology, Teikyo University Tokyo, Japan
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Abstract
Bacterial sphingomyelinases and phospholipases are a heterogeneous group of esterases which are usually surface associated or secreted by a wide variety of Gram-positive and Gram-negative bacteria. These enzymes hydrolyze sphingomyelin and glycerophospholipids, respectively, generating products identical to the ones produced by eukaryotic enzymes which play crucial roles in distinct physiological processes, including membrane dynamics, cellular signaling, migration, growth, and death. Several bacterial sphingomyelinases and phospholipases are essential for virulence of extracellular, facultative, or obligate intracellular pathogens, as these enzymes contribute to phagosomal escape or phagosomal maturation avoidance, favoring tissue colonization, infection establishment and progression, or immune response evasion. This work presents a classification proposal for bacterial sphingomyelinases and phospholipases that considers not only their enzymatic activities but also their structural aspects. An overview of the main physiopathological activities is provided for each enzyme type, as are examples in which inactivation of a sphingomyelinase- or a phospholipase-encoding gene impairs the virulence of a pathogen. The identification of sphingomyelinases and phospholipases important for bacterial pathogenesis and the development of inhibitors for these enzymes could generate candidate vaccines and therapeutic agents, which will diminish the impacts of the associated human and animal diseases.
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Matsumoto Y, Sekimizu K. A hyperglycemic silkworm model for evaluating hypoglycemic activity of Rehmanniae Radix, an herbal medicine. Drug Discov Ther 2016; 10:14-8. [PMID: 26902904 DOI: 10.5582/ddt.2016.01016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Silkworm shows hyperglycemia after intake of diet containing large amount of glucose. The hyperglycemic silkworm model is useful for evaluation of anti-diabetic drugs. A hot water extract of Rehmanniae Radix, an herbal medicine, showed hypoglycemic effect against the hyperglycemic silkworms. This method is applicable for quick and simple evaluation of the hypoglycemic activities of different batches of Rehmanniae Radix. Our findings suggest that silkworms have a lot of merit as experimental animals for evaluation of various herbal medicines.
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Affiliation(s)
- Yasuhiko Matsumoto
- Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo
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16
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Nwibo DD, Hamamoto H, Matsumoto Y, Kaito C, Sekimizu K. Current use of silkworm larvae (Bombyx mori) as an animal model in pharmaco-medical research. Drug Discov Ther 2015; 9:133-5. [PMID: 25994065 DOI: 10.5582/ddt.2015.01026] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We advocate the use of silkworm larvae, Bombyx mori, as an animal model for discovery of drug candidates. We have established several disease models using silkworms, which offer technical advantages in drug development and the study of host-pathogen interaction. This mini review briefly describes recent trends in the use of silkworm larvae as a non-mammalian model for drug discovery and it offers suggestions regarding the potential for silkworm use in pharmaceutical-biomedical research.
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Affiliation(s)
- Don Daniel Nwibo
- Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo
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17
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Popat R, Pollitt EJG, Harrison F, Naghra H, Hong KW, Chan KG, Griffin AS, Williams P, Brown SP, West SA, Diggle SP. Conflict of interest and signal interference lead to the breakdown of honest signaling. Evolution 2015; 69:2371-83. [PMID: 26282874 PMCID: PMC4862024 DOI: 10.1111/evo.12751] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 07/17/2015] [Accepted: 07/27/2015] [Indexed: 01/04/2023]
Abstract
Animals use signals to coordinate a wide range of behaviors, from feeding offspring to predator avoidance. This poses an evolutionary problem, because individuals could potentially signal dishonestly to coerce others into behaving in ways that benefit the signaler. Theory suggests that honest signaling is favored when individuals share a common interest and signals carry reliable information. Here, we exploit the opportunities offered by bacterial signaling to test these predictions with an experimental evolution approach. We show that: (1) reduced relatedness leads to the relative breakdown of signaling, (2) signaling breaks down by the invasion of mutants that show both reduced signaling and reduced response to signal, (3) the genetic route to signaling breakdown is variable, and (4) the addition of artificial signal, to interfere with signal information, also leads to reduced signaling. Our results provide clear support for signaling theory, but we did not find evidence for previously predicted coercion at intermediate relatedness, suggesting that mechanistic details can alter the qualitative nature of specific predictions. Furthermore, populations evolved under low relatedness caused less mortality to insect hosts, showing how signal evolution in bacterial pathogens can drive the evolution of virulence in the opposite direction to that often predicted by theory.
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Affiliation(s)
- Roman Popat
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, United Kingdom.,Centre for Immunity, Infection and Evolution, Ashworth Laboratories, University of Edinburgh, King's Buildings, West Mains Road, Edinburgh, EH9 3JT, United Kingdom
| | - Eric J G Pollitt
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Freya Harrison
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Hardeep Naghra
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Kar-Wai Hong
- Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Kok-Gan Chan
- Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Ashleigh S Griffin
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, United Kingdom
| | - Paul Williams
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Sam P Brown
- Centre for Immunity, Infection and Evolution, Ashworth Laboratories, University of Edinburgh, King's Buildings, West Mains Road, Edinburgh, EH9 3JT, United Kingdom
| | - Stuart A West
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, United Kingdom
| | - Stephen P Diggle
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, United Kingdom.
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18
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Miyashita A, Kizaki H, Kawasaki K, Sekimizu K, Kaito C. Primed immune responses to gram-negative peptidoglycans confer infection resistance in silkworms. J Biol Chem 2014; 289:14412-21. [PMID: 24706746 DOI: 10.1074/jbc.m113.525139] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
A heightened immune response, in which immune responses are primed by repeated exposure to a pathogen, is an important characteristic of vertebrate adaptive immunity. In the present study, we examined whether invertebrate animals also exhibit a primed immune response. The LD50 of Gram-negative enterohemorrhagic Escherichia coli O157:H7 Sakai in silkworms was increased 100-fold by pre-injection of heat-killed Sakai cells. Silkworms pre-injected with heat-killed cells of a Gram-positive bacterium, Staphylococcus aureus, did not have resistance to Sakai. Silkworms preinjected with enterohemorrhagic E. coli peptidoglycans, cell surface components of bacteria, were resistant to Sakai infection. Silkworms preinjected with S. aureus peptidoglycans, however, were not resistant to Sakai. Silkworms preinjected with heat-killed Sakai cells showed persistent resistance to Sakai infection even after pupation. Repeated injection of heat-killed Sakai cells into the silkworms induced earlier and greater production of antimicrobial peptides than a single injection of heat-killed Sakai cells. These findings suggest that silkworm recognition of Gram-negative peptidoglycans leads to a primed immune reaction and increased resistance to a second round of bacterial infection.
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Affiliation(s)
- Atsushi Miyashita
- From the Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 3-1, 7-chome, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hayato Kizaki
- From the Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 3-1, 7-chome, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kiyoshi Kawasaki
- the Laboratory of Microbiology, Faculty of Pharmaceutical Sciences, Doshisha Women's College, Kyotanabe 610-0395, Japan
| | - Kazuhisa Sekimizu
- From the Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 3-1, 7-chome, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Chikara Kaito
- From the Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 3-1, 7-chome, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan,
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19
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Hamamoto H, Urai M, Paudel A, Horie R, Murakami K, Sekimizu K. [Identification of novel therapeutically effective antibiotics using silkworm infection model]. YAKUGAKU ZASSHI 2012; 132:79-84. [PMID: 22214583 DOI: 10.1248/yakushi.132.79] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Most antibiotics obtained by in vitro screening with antibacterial activity have inappropriate properties as medicines due to their toxicity and pharmacodynamics in animal bodies. Thus, evaluation of the therapeutic effects of these samples using animal models is essential in the crude stage. Mammals are not suitable for therapeutic evaluation of a large number of samples due to high costs and ethical issues. We propose the use of silkworms (Bombyx mori) as model animals for screening therapeutically effective antibiotics. Silkworms are infected by various pathogenic bacteria and are effectively treated with similar ED(50) values of clinically used antibiotics. Furthermore, the drug metabolism pathways, such as cytochrome P450 and conjugation systems, are similar between silkworms and mammals. Silkworms have many advantages compared with other infection models, such as their 1) low cost, 2) few associated ethical problems, 3) adequate body size for easily handling, and 4) easier separation of organs and hemolymph. These features of the silkworm allow for efficient screening of therapeutically effective antibiotics. In this review, we discuss the advantages of the silkworm model in the early stages of drug development and the screening results of some antibiotics using the silkworm infection model.
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Affiliation(s)
- Hiroshi Hamamoto
- Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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20
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Chieda Y, Iiyama K, Lee JM, Kusakabe T, Yasunaga-Aoki C, Shimizu S. Virulence of an exotoxin A-deficient strain of Pseudomonas aeruginosa toward the silkworm, Bombyx mori. Microb Pathog 2011; 51:407-14. [PMID: 21945328 DOI: 10.1016/j.micpath.2011.09.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Revised: 08/31/2011] [Accepted: 09/06/2011] [Indexed: 01/01/2023]
Abstract
We studied the contribution of exotoxin A to the virulence of Pseudomonas aeruginosa against the silkworm, Bombyx mori. First, an exotoxin A-deficient mutant strain (PAO1toxA) was created, and its virulence compared with that of the parental PAO1 strain. In a short-term mortality assay, the mutant harboring pBBR1MCS2 did not kill B. mori until 120 h after inoculation and complementation of the corresponding gene in trans restored the strain's virulence. Next, to ascertain whether or not it lost all virulence, PAO1toxA (pBBR1MCS2, pGFP) was used in a long-term mortality assay. B. mori inoculated with the mutant strain did not die until early in the 5th instar (240 h after inoculation). However, 50% of the inoculated B. mori died late in the 5th instar or in the early pupal stage (408 h after inoculation). All had died by the pupal stage (600 h after inoculation). The mutant strain was isolated from dead larvae and cocoons. The bacterial population of PAO1toxA in hemolymph reached 4.77 × 10(7) cfu/ml. These results indicated that exotoxin A acts as a virulence factor in B. mori and that other virulence factor(s) are involved during the late stages of infection.
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Affiliation(s)
- Yuuka Chieda
- Laboratory of Insect Pathology and Microbial Control, Institute of Biological Control, Graduate School, Kyushu University, Hakozaki 6-10-1, Higashi-ku, Fukuoka 812-8581, Japan
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21
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Matsumoto Y, Miyazaki S, Fukunaga DH, Shimizu K, Kawamoto S, Sekimizu K. Quantitative evaluation of cryptococcal pathogenesis and antifungal drugs using a silkworm infection model with Cryptococcus neoformans. J Appl Microbiol 2011; 112:138-46. [PMID: 22040451 DOI: 10.1111/j.1365-2672.2011.05186.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
AIMS To develop an in vivo system that could quantitatively evaluate the therapeutic effects of antifungal drugs using a silkworm infection model with Cryptococcus neoformans. METHODS AND RESULTS Silkworms reared at 37°C died after an injection of viable serotype A C. neoformans fungus into the haemolymph. The serotype A C. neoformans, which is known to have higher mammal pathogenicity than the serotype D, was also more virulent against the silkworm. Furthermore, the deletion mutants of genes gpa1, pka1 and cna1, which are genes known to be necessary for the pathogenesis in mammals, showed an increase in the number of fungal cells necessary to kill half of the silkworm population (LD(50) value). Antifungal drugs, amphotericin B, flucytosine, fluconazole and ketoconazole, showed therapeutic effects in silkworms infected with C. neoformans. However, amphotericin B was not therapeutically effective when injected into the silkworm intestine, comparable to the fact that amphotericin B is not absorbed by the intestine in mammals. CONCLUSIONS The silkworm-C. neoformans infection model is useful for evaluating the therapeutic effects of antifungal drugs. SIGNIFICANCE AND IMPACT OF THE STUDY The silkworm infection model has various advantages for screening antifungal drug candidates. We can also elucidate the cryptococcal pathogenesis and evaluate the in vivo pharmacokinetics and toxicity of each drug.
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Affiliation(s)
- Y Matsumoto
- Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
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22
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Miyazaki S, Matsumoto Y, Sekimizu K, Kaito C. Evaluation of Staphylococcus aureus virulence factors using a silkworm model. FEMS Microbiol Lett 2011; 326:116-24. [PMID: 22092964 DOI: 10.1111/j.1574-6968.2011.02439.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 08/29/2011] [Accepted: 10/17/2011] [Indexed: 02/04/2023] Open
Abstract
Previous studies have indicated that the silkworm model is useful for identifying virulence genes of Staphylococcus aureus, a human pathogenic bacterium. Here we examined the scope of S. aureus virulence factors that can be evaluated using the silkworm model. Gene-disrupted mutants of the agr locus, arlS gene and saeS gene, which regulate the expression of cell surface adhesins and hemolysins, exhibited attenuated virulence in silkworms. Mutants of the hla gene encoding α-hemolysin, the hlb gene encoding β-hemolysin, and the psmα and psmβ operons encoding cytolysins, however, showed virulence in silkworms indistinguishable from that of the parent strain. Thus, these S. aureus cytolysins are not required for virulence in silkworms. In contrast, the gene-disrupted mutants of clfB, fnbB and sdrC, which encode cell-wall-anchored proteins, attenuated S. aureus virulence in silkworms. In addition, the mutant of the srtA gene encoding sortase A, which anchors cell-wall proteins, showed attenuated virulence in silkworms. These findings suggest that the silkworm model can be used to evaluate S. aureus cell-wall proteins and regulatory proteins as virulence factors.
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Affiliation(s)
- Shinya Miyazaki
- Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Japan
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23
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Hanada Y, Sekimizu K, Kaito C. Silkworm apolipophorin protein inhibits Staphylococcus aureus virulence. J Biol Chem 2011; 286:39360-9. [PMID: 21937431 DOI: 10.1074/jbc.m111.278416] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Silkworm hemolymph inhibits hemolysin production by Staphylococcus aureus. We purified a factor in the silkworm hemolymph responsible for this inhibitory activity. The final fraction with the greatest specific activity contained 220- and 74-kDa proteins. Determination of the N-terminal amino acid sequence revealed that the 220- and 74-kDa proteins were apolipophorin I and apolipophorin II, respectively, indicating that the factor was apolipophorin (ApoLp). The purified ApoLp fraction showed decreased expression of S. aureus hla encoding α-hemolysin, hlb encoding β-hemolysin, saeRS, and RNAIII, which activate the expression of these hemolysin genes. Injection of an anti-ApoLp antibody into the hemolymph increased the sensitivity of silkworms to the lethal effect of S. aureus. Hog gastric mucin, a mammalian homologue of ApoLp, decreased the expression of S. aureus hla and hlb. These findings suggest that ApoLp in the silkworm hemolymph inhibits S. aureus virulence and contributes to defense against S. aureus infection and that its activity is conserved in mammalian mucin.
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Affiliation(s)
- Yuichi Hanada
- Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 3-1, 7-chome, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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24
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Kaito C, Usui K, Kyuma T, Sekimizu K. Isolation of mammalian pathogenic bacteria using silkworms. Drug Discov Ther 2011; 5:66-70. [DOI: 10.5582/ddt.2011.v5.2.66] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Chikara Kaito
- Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo
| | - Kimihito Usui
- Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo
| | - Tatsuhiko Kyuma
- Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo
| | - Kazuhisa Sekimizu
- Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo
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25
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Translocation of Pseudomonas aeruginosa from the intestinal tract is mediated by the binding of ExoS to an Na,K-ATPase regulator, FXYD3. Infect Immun 2010; 78:4511-22. [PMID: 20805335 DOI: 10.1128/iai.00428-10] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The intestinal tract is considered the most important reservoir of Pseudomonas aeruginosa in intensive care units (ICUs). Gut colonization by P. aeruginosa underlies the development of invasive infections such as gut-derived sepsis. Intestinal colonization by P. aeruginosa is associated with higher ICU mortality rates. The translocation of endogenous P. aeruginosa from the colonized intestinal tract is an important pathogenic phenomenon. Here we identify bacterial and host proteins associated with bacterial penetration through the intestinal epithelial barrier. We first show by comparative genomic hybridization analysis that the exoS gene, encoding the type III effector protein, ExoS, was specifically detected in a clinical isolate that showed higher virulence in silkworms following midgut injection. We further show using a silkworm oral infection model that exoS is required both for virulence and for bacterial translocation from the midgut to the hemolymph. Using a bacterial two-hybrid screen, we show that the mammalian factor FXYD3, which colocalizes with and regulates the function of Na,K-ATPase, directly binds ExoS. A pulldown assay revealed that ExoS binds to the transmembrane domain of FXYD3, which also interacts with Na,K-ATPase. Na,K-ATPase controls the structure and barrier function of tight junctions in epithelial cells. Collectively, our results suggest that ExoS facilitates P. aeruginosa penetration through the intestinal epithelial barrier by binding to FXYD3 and thereby impairing the defense function of tight junctions against bacterial penetration.
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26
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Hamamoto H, Tonoike A, Narushima K, Horie R, Sekimizu K. Silkworm as a model animal to evaluate drug candidate toxicity and metabolism. Comp Biochem Physiol C Toxicol Pharmacol 2009; 149:334-9. [PMID: 18804554 DOI: 10.1016/j.cbpc.2008.08.008] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Revised: 08/25/2008] [Accepted: 08/26/2008] [Indexed: 11/23/2022]
Abstract
To evaluate the feasibility of using the silkworm as a model animal for screening drug candidates, we examined whether the lethal dose of cytotoxic chemicals in silkworm, Bombyx mori, were consistent with those in mammals, and compared the metabolic pathways of these drugs between silkworms and mice. The lethal dose levels of cytotoxic chemicals in silkworms were consistent with those in mammals. We examined the fate of model drugs, 4-methyl umbelliferone, umbelliferone, and 7-ethoxycoumarine, in silkworm larvae. The half-life of 4-methyl umbelliferone in the silkworm larvae hemolymph was 7.0+/-0.1 min, similar to that in mouse blood. In silkworm larvae, 4-methyl umbelliferone was conjugated with glucose, whereas in mammals it is conjugated with glucuronate or sulfate. These results are consistent with a previous report that UDP-glucosyltransferase catalyzes the conjugation of 4-methyl umbelliferone. The glucose-conjugation reaction of 4-methyl umbelliferone was observed in microsomal fractions of fat bodies isolated from silkworms. Furthermore, most umbelliferone and 7-ethoxycoumarine injected into the hemolymph of silkworms was eliminated through the feces in the glucose-conjugated form. These findings suggest that chemicals are metabolized through a pathway common to both mammals and silkworms: reaction with cytochrome P450, conjugation with hydroxylated compounds, and excretion.
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Affiliation(s)
- Hiroshi Hamamoto
- Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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27
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Usui K, Miyazaki S, Kaito C, Sekimizu K. Purification of a soil bacteria exotoxin using silkworm toxicity to measure specific activity. Microb Pathog 2009; 46:59-62. [DOI: 10.1016/j.micpath.2008.10.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 10/17/2008] [Accepted: 10/17/2008] [Indexed: 10/21/2022]
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28
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Seabra R, Bhogal N. Hospital infections, animal models and alternatives. Eur J Clin Microbiol Infect Dis 2008; 28:561-8. [DOI: 10.1007/s10096-008-0680-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Accepted: 11/28/2008] [Indexed: 01/05/2023]
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29
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Matsumoto Y, Kaito C, Morishita D, Kurokawa K, Sekimizu K. Regulation of exoprotein gene expression by the Staphylococcus aureus cvfB gene. Infect Immun 2007; 75:1964-72. [PMID: 17283102 PMCID: PMC1865683 DOI: 10.1128/iai.01552-06] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We previously reported that the cvfB gene (SA1223) of Staphylococcus aureus is responsible for the virulence of this pathogenic bacterium. We show here that the cvfB gene regulates exoprotein gene expression. In a cvfB gene deletion mutant, hemolysin, DNase, and protease production were decreased, whereas protein A expression was increased. The amount of RNAIII, the transcript from the P3 promoter in the agr locus that regulates the expression of various virulence factors, was also reduced in the cvfB mutant. In addition, P2 and P3 promoter activity in the agr locus was decreased in the mutant. Under the genetic background of the agr-null mutation, cvfB gene disruption decreased the production levels of DNase and protease. Moreover, the cvfB and agr double mutant was less virulent than the agr mutant in silkworms. These results suggest that the cvfB gene product contributes to the expression of virulence factors and to pathogenicity via both agr-dependent and agr-independent pathways.
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Affiliation(s)
- Yasuhiko Matsumoto
- Graduate School of Pharmaceutical Sciences, University of Tokyo, 3-1, 7-Chome, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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