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Park JW, Park SK, Jeong CY, Kwon HG, Lee JH, Kang SK, Kim SW, Kim SR. Microbial Community Changes in Silkworms Suspected of Septicemia and Identification of Serratia sp. Int J Mol Sci 2024; 25:3957. [PMID: 38612767 PMCID: PMC11012086 DOI: 10.3390/ijms25073957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2024] [Revised: 03/25/2024] [Accepted: 03/29/2024] [Indexed: 04/14/2024] Open
Abstract
Diseases that occur in silkworms include soft rot, hardening disease, digestive diseases, and sepsis. However, research on the causes of bacterial diseases occurring in silkworms and the resulting changes in the microbial community is lacking. Therefore, we examined the morphological characteristics of sepsis and changes in the microbial community between silkworms that exhibit a unique odor and healthy silkworms; thus, we established a relationship between disease-causing microorganisms and sepsis. After producing a 16S rRNA amplicon library for samples showing sepsis, we obtained information on the microbial community present in silkworms using next-generation sequencing. Compared to that in healthy silkworms, in silkworms with sepsis, the abundance of the Firmicutes phylum was significantly reduced, while that of Proteobacteria was increased. Serratia sp. was dominant in silkworms with sepsis. After bacterial isolation, identification, and reinfection through the oral cavity, we confirmed this organism as the disease-causing agent; its mortality rate was 1.8 times higher than that caused by Serratia marcescens. In summary, we identified a new causative bacterium of silkworm sepsis through microbial community analysis and confirmed that the microbial community balance was disrupted by the aberrant proliferation of certain bacteria.
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Affiliation(s)
- Jong Woo Park
- Department of Agricultural Biology, National Institute of Agricultural Sciences, Wanju-gun, Jeonju 55365, Jeollabuk-do, Republic of Korea; (S.K.P.); (C.Y.J.); (H.G.K.); (J.H.L.); (S.K.K.); (S.-W.K.); (S.-R.K.)
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Lin DJ, Zhou JX, Ali A, Fu HY, Gao SJ, Jin L, Fang Y, Wang JD. Biocontrol efficiency and characterization of insecticidal protein from sugarcane endophytic Serratia marcescens (SM) against oriental armyworm Mythimna separata (Walker). Int J Biol Macromol 2024; 262:129978. [PMID: 38340916 DOI: 10.1016/j.ijbiomac.2024.129978] [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] [Received: 11/10/2023] [Revised: 01/25/2024] [Accepted: 02/02/2024] [Indexed: 02/12/2024]
Abstract
The plant endophytic bacteria are a great source of nature insecticides. However, no such endophytic bacteria have been found in sugarcane, to address this gap, we isolated and identified a strain of Serratia marcescens with moderate insecticidal activity from sugarcane. Taken armyworm Mythimna separata as example, the mortality rates of oral infection and injection infection were 47.06 % and 91 %, respectively. The SM has significant negative affect on the growth, development, and reproduction of M. separata. After determining that these insecticidal substances, 33 potential virulence proteins were screened through the identification and prediction of bacterial proteins. Later we confirmed serralysin was a vital toxic protein from SM that caused M. separata death by prokaryotic expression. In addition, we also found that the intestinal tissue cells infected with SM or serralysin were severely diseased, which may be a major factor in M. separata demise. Finally, through gene expression level, protein molecular docking, we found the aminopeptidase-N would be one of the potential receptors of serralysin. Taken together, our findings indicate that sugarcane endophyte S. marcescens may be beneficial for pest control in sugarcane and explain its insecticidal mechanism. This study provides new ideas and materials for the biological control of pests.
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Affiliation(s)
- Dong-Jiang Lin
- National Engineering Research Center of Sugarcane, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China
| | - Jiang-Xiong Zhou
- National Engineering Research Center of Sugarcane, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China
| | - Ahmad Ali
- National Engineering Research Center of Sugarcane, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China
| | - Hua-Ying Fu
- National Engineering Research Center of Sugarcane, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China
| | - San-Ji Gao
- National Engineering Research Center of Sugarcane, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China
| | - Lin Jin
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Yong Fang
- Hunan Agricultural Biotechnology Research Institute, Hunan Academy of Agriculture science, Changsha, Hunan 410125, PR China
| | - Jin-da Wang
- National Engineering Research Center of Sugarcane, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China.
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Vaselek S, Sarac BE, Uzunkaya AD, Yilmaz A, Karaaslan C, Alten B. Identification of Ochrobactrum as a bacteria with transstadial transmission and potential for application in paratransgenic control of leishmaniasis. Parasitol Res 2024; 123:82. [PMID: 38175278 DOI: 10.1007/s00436-023-08087-9] [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] [Received: 09/09/2023] [Accepted: 12/05/2023] [Indexed: 01/05/2024]
Abstract
Leishmaniasis is a zoonotic vector-borne disease with worldwide distribution. All current approaches in leishmaniasis control or development of vaccines/cures showed only limited success. Recently, paratransgenesis has been marked as a promising strategy for leishmaniasis control. Thus, the investigations of the gut microbial content of sand flies have gained popularity. Gut microbial composition of the laboratory colony of Phlebotomus papatasi was investigated via microbial culturomics approach which refers to the combination of multiple culture conditions and different selective and/or enriched culture mediums, followed by 16S rDNA sequencing. Investigations were conducted on three offspring generations, with six samplings of immature stages (four larval samplings, one pre-pupa, one pupa) and samplings of adults before and after blood feeding. The aim was to determine if microbiome changes during the sand fly development and to identify bacteria with transstadial potential. The presence of 8 bacterial taxa (Bacillus sp., Terribacillus sp., Staphylococcus sp., Alcaligenes sp., Microbacterium sp., Leucobacter sp., Ochrobactrum sp. and Enterobacter sp.), 2 fungi (Fusarium sp. and Acremonium sp.) and 1 yeast (Candida sp.) were recorded. Gram-positive bacteria were more diverse, but gram-negative bacteria were more abundant. All taxa were recorded among immature stage samples, while only one bacterium was detected in adults. Microbial diversity among larval samples was stable, with a steady decrease in pre-pupa and pupa, resulting in the survival of only Ochrobactrum sp. in adults. Abundance of microbes was higher when larvae were actively feeding, with a gradual decrease after larvae stopped feeding and commenced pupation. Ochrobactrum sp. is the bacteria with transstadial potential, worthy of future in-depth analysis for the application in paratransgenic approach for the control of Leishmania sp.
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Affiliation(s)
- Slavica Vaselek
- Hacettepe University, Faculty of Science, Department of Biology, Ecology Section, Ankara, Türkiye.
| | - Basak Ezgi Sarac
- Hacettepe University, Faculty of Science, Department of Biology, Molecular Biology Section, Ankara, Türkiye
| | - Ali Doruk Uzunkaya
- Hacettepe University, Faculty of Science, Department of Biology, Molecular Biology Section, Ankara, Türkiye
| | - Ayda Yilmaz
- Hacettepe University, Faculty of Science, Department of Biology, Ecology Section, Ankara, Türkiye
| | - Cagatay Karaaslan
- Hacettepe University, Faculty of Science, Department of Biology, Molecular Biology Section, Ankara, Türkiye
| | - Bulent Alten
- Hacettepe University, Faculty of Science, Department of Biology, Ecology Section, Ankara, Türkiye
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Lee J, Kim JU, Lee BL, Kim JK. Alteration of lipopolysaccharide O antigen leads to avirulence of gut-colonizing Serratia marcescens. Front Microbiol 2023; 14:1278917. [PMID: 38029092 PMCID: PMC10665507 DOI: 10.3389/fmicb.2023.1278917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 10/26/2023] [Indexed: 12/01/2023] Open
Abstract
The reason why the potent entomopathogen Serratia marcescens fails to kill insects through oral infection is unknown. To compare effects of septic injection and oral administration of S. marcescens, we used a model bean bug, Riptortus pedestris. Most R. pedestris insects survived oral infections, but not septic infections. Although the number of S. marcescens cells in hemolymph after oral infection, which were originated from gut-colonizing S. marcescens, was higher than the fatal number of cells used in septic injection, they did not kill host insects, suggesting a loss of virulence in gut-colonizing S. marcescens cells. When gut-colonizing S. marcescens cells were septically injected into insects, they failed to kill R. pedestris and survive in hemolymph. To understand the avirulence mechanisms in gut-colonizing bacteria, lipopolysaccharides of S. marcescens were analyzed and revealed that the O antigen was lost during gut colonization. Gut-colonizing S. marcescens cells were resistant to humoral immune responses but susceptible to cellular immune responses, easily succumbing to phagocytosis of hemocytes. When cellular immunity was suppressed, the gut-colonizing S. marcescens cells recovered their virulence and killed insects through septic injection. These results suggest that a key mechanism of avirulence in orally infected S. marcescens is the loss of the O antigen, resulting in susceptibility to host's cellular immune responses.
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Affiliation(s)
- Junbeom Lee
- Metabolomics Research Center for Functional Materials, Kyungsung University, Busan, Republic of Korea
| | - Jong Uk Kim
- Host Defense Protein Laboratory, College of Pharmacy, Pusan National University, Busan, Republic of Korea
| | - Bok Luel Lee
- Host Defense Protein Laboratory, College of Pharmacy, Pusan National University, Busan, Republic of Korea
| | - Jiyeun Kate Kim
- Department of Microbiology, Kosin University College of Medicine, Busan, Republic of Korea
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Ge SX, Li JX, Jiang ZH, Zong SX, Ren LL. Cradle for the newborn Monochamus saltuarius: Microbial associates to ward off entomopathogens and disarm plant defense. INSECT SCIENCE 2023; 30:1165-1182. [PMID: 36377192 DOI: 10.1111/1744-7917.13148] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 10/19/2022] [Accepted: 11/03/2022] [Indexed: 06/16/2023]
Abstract
The Japanese pine sawyer, Monochamus saltuarius, as a beetle vector of Bursaphelenchus xylophilus (pine wood nematode), is an economically important forest pest in Eurasia. To feed on the phloem and xylem of conifers, M. saltuarius needs to overcome various stress factors, including coping with entomopathogenic bacteria and also various plant secondary compounds (PSCs). As an important adaptation strategy to colonize host trees, M. saltuarius deposit eggs in oviposition pits to shield their progeny. These pits harbor bacterial communities that are involved in the host adaptation of M. saltuarius to the conifers. However, the composition, origin, and functions of these oviposition pit bacteria are rarely understood. In this study, we investigated the bacterial community associated with M. saltuarius oviposition pits and their ability to degrade PSCs. Results showed that the bacterial community structure of M. saltuarius oviposition pits significantly differed from that of uninfected phloem. Also, the oviposition pit bacteria were predicted to be enriched in PSC degradation pathways. The microbial community also harbored a lethal strain of Serratia, which was significantly inhibited. Meanwhile, metatranscriptome analysis indicated that genes involved in PSCs degradation were expressed complementarily among the microbial communities of oviposition pits and secretions. In vitro degradation showed that bacteria cultured from oviposition pits degraded more monoterpenes and flavonoids than bacteria cultured from uninfected phloem isolates. Disinfection of oviposition pits increased the mortality of newly hatched larvae and resulted in a significant decrease in body weight in the early stages. Overall, our results reveal that M. saltuarius construct oviposition pits that harbor a diverse microbial community, with stronger PSCs degradation abilities and a low abundance of entomopathogenic bacteria, resulting in the increased fitness of newly hatched larvae.
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Affiliation(s)
- Si-Xun Ge
- Beijing Key Laboratory for Forest Pest Control, Beijing Forestry University, Beijing, China
| | - Jia-Xing Li
- Beijing Key Laboratory for Forest Pest Control, Beijing Forestry University, Beijing, China
| | | | - Shi-Xiang Zong
- Beijing Key Laboratory for Forest Pest Control, Beijing Forestry University, Beijing, China
- Sino-French Joint Laboratory for Invasive Forest Pests in Eurasia, Beijing Forestry University-French National Research Institute for Agriculture, Food and Environment (INRAE), Beijing, China
| | - Li-Li Ren
- Beijing Key Laboratory for Forest Pest Control, Beijing Forestry University, Beijing, China
- Sino-French Joint Laboratory for Invasive Forest Pests in Eurasia, Beijing Forestry University-French National Research Institute for Agriculture, Food and Environment (INRAE), Beijing, China
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Histometric and morphological damage caused by Serratia marcescens to the tick Rhipicephalus microplus (Acari: Ixodidae). Arch Microbiol 2022; 204:677. [DOI: 10.1007/s00203-022-03275-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 09/09/2022] [Accepted: 09/28/2022] [Indexed: 11/02/2022]
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Medina V, Rosso BE, Soria M, Gutkind GO, Pagano EA, Zavala JA. Feeding on soybean crops changed gut bacteria diversity of the southern green stinkbug (Nezara viridula) and reduced negative effects of some associated bacteria. PEST MANAGEMENT SCIENCE 2022; 78:4608-4617. [PMID: 35837785 DOI: 10.1002/ps.7080] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 07/07/2022] [Accepted: 07/15/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND The southern green stinkbug (Nezara viridula) is a mayor pest of soybean. However, the mechanism underlying stinkbug resistance to soybean defenses is yet ignored. Although gut bacteria could play an essential role in tolerating plant defenses, most studies testing questions related to insect-plant-bacteria interactions have been performed in laboratory condition. Here we performed experiments in laboratory and field conditions with N. viridula and its gut bacteria, studying gut lipid peroxidaxion levels and cysteine activity in infected and unifected nymphs, testing the hypothesis that feeding on field-grown soybean decreases bacterial abundance in stinkbugs. RESULTS Gut bacterial abundance and infection ratio were higher in N. viridula adults reared in laboratory than in those collected from soybean crops, suggesting that stinkbugs in field conditions may modulate gut bacterial colonization. Manipulating gut microbiota by infecting stinkbugs with Yokenella sp. showed that these bacteria abundance decreased in field conditions, and negatively affected stinkbugs performance and were more aggressive in laboratory rearing than in field conditions. Infected nymphs that fed on soybean pods had lower mortality, higher mass and shorter development period than those reared in the laboratory, and suggested that field conditions helped nymphs to recover from Yokenella sp. infection, despite of increased lipid peroxidation and decreased cysteine proteases activity in nymphs' guts. CONCLUSIONS Our results demonstrated that feeding on field-grown soybean reduced bacterial abundance and infection in guts of N. viridula and highlighted the importance to test functional activities or pathogenicity of microbes under realistic field conditions prior to establish conclusions on three trophic interactions. © 2022 Society of Chemical Industry.
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Affiliation(s)
- Virginia Medina
- Facultad de Agronomía, Cátedra de Bioquímica - Instituto de Investigaciones en Biociencias Agrícolas y Ambientales (INBA-CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Bruno E Rosso
- Facultad de Agronomía, Cátedra de Microbiologia - Instituto de Investigaciones en Biociencias Agrícolas y Ambientales (INBA-CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Marcelo Soria
- Facultad de Agronomía, Cátedra de Microbiologia - Instituto de Investigaciones en Biociencias Agrícolas y Ambientales (INBA-CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Gabriel O Gutkind
- Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina (CONICET), Buenos Aires, Argentina
| | - Eduardo A Pagano
- Facultad de Agronomía, Cátedra de Bioquímica - Instituto de Investigaciones en Biociencias Agrícolas y Ambientales (INBA-CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Jorge A Zavala
- Facultad de Agronomía, Cátedra de Bioquímica - Instituto de Investigaciones en Biociencias Agrícolas y Ambientales (INBA-CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina (CONICET), Buenos Aires, Argentina
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Williams DJ, Grimont PAD, Cazares A, Grimont F, Ageron E, Pettigrew KA, Cazares D, Njamkepo E, Weill FX, Heinz E, Holden MTG, Thomson NR, Coulthurst SJ. The genus Serratia revisited by genomics. Nat Commun 2022; 13:5195. [PMID: 36057639 PMCID: PMC9440931 DOI: 10.1038/s41467-022-32929-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Accepted: 08/24/2022] [Indexed: 11/24/2022] Open
Abstract
The genus Serratia has been studied for over a century and includes clinically-important and diverse environmental members. Despite this, there is a paucity of genomic information across the genus and a robust whole genome-based phylogenetic framework is lacking. Here, we have assembled and analysed a representative set of 664 genomes from across the genus, including 215 historic isolates originally used in defining the genus. Phylogenomic analysis of the genus reveals a clearly-defined population structure which displays deep divisions and aligns with ecological niche, as well as striking congruence between historical biochemical phenotyping data and contemporary genomics data. We highlight the genomic, phenotypic and plasmid diversity of Serratia, and provide evidence of different patterns of gene flow across the genus. Our work provides a framework for understanding the emergence of clinical and other lineages of Serratia.
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Affiliation(s)
- David J Williams
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, UK
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - Patrick A D Grimont
- Unité Biodiversité des Bactéries Pathogènes Emergentes, INSERM Unité 389, Institut Pasteur, Paris, France
| | - Adrián Cazares
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK
- European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, UK
| | - Francine Grimont
- Unité Biodiversité des Bactéries Pathogènes Emergentes, INSERM Unité 389, Institut Pasteur, Paris, France
| | - Elisabeth Ageron
- Unité Biodiversité des Bactéries Pathogènes Emergentes, INSERM Unité 389, Institut Pasteur, Paris, France
- Université Paris Cité, INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, Paris, France
| | | | - Daniel Cazares
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - Elisabeth Njamkepo
- Institut Pasteur, Université de Paris, Unité des Bactéries Pathogènes Entériques, Paris, France
| | - François-Xavier Weill
- Institut Pasteur, Université de Paris, Unité des Bactéries Pathogènes Entériques, Paris, France
| | - Eva Heinz
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK
- Departments of Vector Biology and Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | | | - Nicholas R Thomson
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK.
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK.
| | - Sarah J Coulthurst
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, UK.
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Lee J, Lee DW. Insecticidal Serralysin of Serratia marcescens Is Detoxified in M3 Midgut Region of Riptortus pedestris. Front Microbiol 2022; 13:913113. [PMID: 35711769 PMCID: PMC9197470 DOI: 10.3389/fmicb.2022.913113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 05/06/2022] [Indexed: 11/18/2022] Open
Abstract
Riptortus pedestris insect indiscriminately acquires not only the symbiotic bacterium Burkholderia insecticola, but also entomopathogens that are abundant in the soil via feeding. However, it is unclear how the host insect survives oral infections of entomopathogens. A previous study suggested that serralysin, a potent virulence factor produced by Serratia marcescens, suppresses cellular immunity by degrading adhesion molecules, thereby contributing to bacterial pathogenesis. Here, we observed that S. marcescens orally administered to R. pedestris stably colonized the insect midgut, while not exhibiting insecticidal activity. Additionally, oral infection with S. marcescens did not affect the host growth or fitness. When co-incubated with the midgut lysates of R. pedestris, serralysin was remarkably degraded. The detoxification activity against serralysin was enhanced in the midgut extract of gut symbiont-colonizing insects. The mRNA expression levels of serralysin genes were negligible in M3-colonizing S. marcescens. M3-colonizing S. marcescens did not produce serralysin toxin. Immunoblot analyses revealed that serralysin was not detected in the M3 midgut region. The findings of our study suggest that orally infected S. marcescens lose entomopathogenicity through host-derived degrading factors and suppression of serralysin.
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Affiliation(s)
- Junbeom Lee
- Metabolomics Research Center for Functional Materials, Kyungsung University, Busan, South Korea
| | - Dae-Weon Lee
- Metabolomics Research Center for Functional Materials, Kyungsung University, Busan, South Korea.,Department of SmartBio, Kyungsung University, Busan, South Korea
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Devi S, Saini HS, Kaur S. Assessing the pathogenicity of gut bacteria associated with tobacco caterpillar Spodoptera litura (Fab.). Sci Rep 2022; 12:8257. [PMID: 35585189 PMCID: PMC9117240 DOI: 10.1038/s41598-022-12319-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 05/09/2022] [Indexed: 11/08/2022] Open
Abstract
The symbiotic relationship between insects and gut microbes contributes to their fitness by serving immense range of functions viz. nutrition and digestion, detoxification, communication and reproduction etc. However, this relationship between insect and gut microbes varies from mutualistic to pathogenic. Gut microbes become pathogenic when the healthy normal microbial composition is perturbed leading to the death of insect host. Spodoptera litura (Fab.) is a polyphagous pest that causes significant damage to many agricultural crops. The management of this pest primarily depends upon chemical insecticides which have resulted in development of resistance. Thus in search for alternative strategies, culturable gut bacteria isolated from S. litura were screened for insecticidal potential. Among these Serratia marcescens and Enterococcus mundtii induced higher larval mortality in S. litura. The mortality rate increased from 32 to 58% due to S. marcescens at concentrations ranging from 2.6 × 108 to 5.2 × 109 cfu/ml and 26 to 52% in case of E. mundtii due to increase in concentration from 4.6 × 108 to 6.1 × 109 cfu/ml. Both the bacteria negatively affected the development, nutritional physiology and reproductive potential of insect. The results indicated a change in gut microbial composition as well as damage to the gut epithelial membrane. Invasion of gut bacteria into the haemocoel led to septicaemia and ultimately death of host insect. In conclusion both these gut bacteria may serve as potential biocontrol agents against S. litura.
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Affiliation(s)
- Sarita Devi
- Department of Zoology, Guru Nanak Dev University, Amritsar, Punjab, 143005, India
| | - Harvinder Singh Saini
- Department of Microbiology, Guru Nanak Dev University, Amritsar, Punjab, 143005, India
| | - Sanehdeep Kaur
- Department of Zoology, Guru Nanak Dev University, Amritsar, Punjab, 143005, India.
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Luo J, Wang Z, Tang F, Feng K. Immune Defense Mechanism of Reticulitermes chinensis Snyder (Blattodea: Isoptera) against Serratia marcescens Bizio. INSECTS 2022; 13:insects13030226. [PMID: 35323524 PMCID: PMC8954430 DOI: 10.3390/insects13030226] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 02/21/2022] [Accepted: 02/22/2022] [Indexed: 12/05/2022]
Abstract
Simple Summary Reticulitermes chinensis Snyder is the most important pest in China. Serratia marcescens (SM1) can infect insects. In our lab, we found that SM1 can kill R. chinensis. However, the mechanisms underlying the immune defense of R. chinensis against SM1 is unknown. Therefore, understanding the interaction between R. chinensis and SM1 is important for termite control. In this study, immune-related differentially expressed genes (DEGs) in R. chinensis were identified and analyzed after SM1 infection. The results increased our understanding of immune responses in pests. This study was helpful for the development of immune suppressive agents in R. chinensis management. Abstract Reticulitermes chinensis Snyder is an important pest species in China. Serratia marcescens Bizio (SM1) is a potent biological bacterium. In our lab, we found that SM1 can kill R. chinensis. To date, the interaction between R. chinensis and SM1 has not been studied. Here, we explored immune responses of R. chinensis against SM1 using transcriptome sequencing. To elucidate immune-related genes, we identified 126,153 unigenes from R. chinensis. In total, 178 immune-related differentially expressed genes (DEGs) were identified. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that many cellular responses were enriched in the top 20 terms. Then, we systematically analyzed several cellular immune pathways involved in the response of R. chinensis to SM1, including phagocytosis, autophagy, and endocytosis pathways. Furthermore, the expression profiles of the cellular immune-related genes were assessed using quantitative reverse-transcription PCR, and the expression levels of the selected genes were upregulated. Further results revealed SM1-mediated activation of humoral immune responses genes, including Toll, IMD, and melanization pathways, which suggested the involvement of humoral immune responses in the defense against SM1. This research elucidated the mechanisms underlying the immune defense of R. chinensis against SM1, providing a solid theoretical basis for exploiting new immune suppressive agents to control R. chinensis. Moreover, this study will facilitate the better control of R. chinensis using SM1.
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Affiliation(s)
- Jian Luo
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China; (J.L.); (Z.W.); (K.F.)
- College of Forestry, Nanjing Forestry University, Nanjing 210037, China
| | - Zhiqiang Wang
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China; (J.L.); (Z.W.); (K.F.)
- College of Forestry, Nanjing Forestry University, Nanjing 210037, China
| | - Fang Tang
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China; (J.L.); (Z.W.); (K.F.)
- College of Forestry, Nanjing Forestry University, Nanjing 210037, China
- Correspondence: ; Tel.: +86-138-1396-6269
| | - Kai Feng
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China; (J.L.); (Z.W.); (K.F.)
- College of Forestry, Nanjing Forestry University, Nanjing 210037, China
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Wang Z, Feng K, Tang F, Xu M. Activation of the Host Immune Response in Hyphantria cunea (Drury) (Lepidoptera: Noctuidae) Induced by Serratia marcescens Bizio. INSECTS 2021; 12:insects12110983. [PMID: 34821784 PMCID: PMC8617612 DOI: 10.3390/insects12110983] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 10/04/2021] [Accepted: 10/27/2021] [Indexed: 01/07/2023]
Abstract
Simple Summary Hyphantria cunea (Drury) is a quarantine pest, due to its extensive host, leading to serious economic losses in the agricultural and forestry industries. To control this pest, it is increasingly important to use microbial pesticides because they are biologically active and ecologically safe. Serratia marcescens Bizio (SM1) is a potential biocontrol bacterium. Although SM1 has a pathogenic role in H. cunea, H. cunea self-defense reduces the pathogenic effect of SM1. In this study, immune-related differentially expressed genes (DEGs) in H. cunea were first identified after SM1 infection, and the immune regulation mode of H. cunea in response to SM1, including antimicrobial peptide synthesis pathways, melanization and cellular immunity, was revealed. According to the analysis, the immune system of H. cunea was induced by SM1. In summary, our study demonstrates how the immune systems of the H. cunea work to resist the infection of SM1, which provides the theoretical basis for researching more efficient microbial pesticides for H. cunea. Abstract Host–pathogen interactions are essential to our understanding of biological pesticides. Hyphantria cunea (Drury) is an important forest pest worldwide. The immune mechanism of the interaction between H. cunea and Serratia marcescens Bizio (SM1) is unclear. First, transcriptome sequencing and quantitative real-time PCR (qRT-PCR) analysis described the H. cunea immune response to SM1. A total of 234 immune-related differentially expressed genes (DEGs) were found. Many immune regulatory genes in three classical pathways were found. Antimicrobial peptides, including attacin B, cecropin A, gloverin, lebocin and diapausin, are involved in defending against SM1 challenge, and are mainly produced by Toll and immune deficiency (IMD) pathways. Some melanization genes were changed in H. cunea, which suggested that H. cunea melanization was activated by SM1. Furthermore, phagocytosis, autophagolysosome and apoptosis pathways in cellular immunity were activated in H. cunea against SM1. Finally, the expression patterns of 10 immune genes were analyzed systematically by qRT-PCR, and most of the genes were upregulated compared to the control. Our studies provide useful information about the immune response of H. cunea under the stress of SM1, which is important to understand how SM1 affects the immune system of H. cunea and provides new ideas to control H. cunea by using SM1.
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Affiliation(s)
- Zhiqiang Wang
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China; (Z.W.); (K.F.); (M.X.)
- College of Forestry, Nanjing Forestry University, Nanjing 210037, China
| | - Kai Feng
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China; (Z.W.); (K.F.); (M.X.)
- College of Forestry, Nanjing Forestry University, Nanjing 210037, China
| | - Fang Tang
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China; (Z.W.); (K.F.); (M.X.)
- College of Forestry, Nanjing Forestry University, Nanjing 210037, China
- Correspondence: ; Tel.: +86-13813966269
| | - Meng Xu
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China; (Z.W.); (K.F.); (M.X.)
- College of Forestry, Nanjing Forestry University, Nanjing 210037, China
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Mikami K, Sonobe K, Ishino K, Noda T, Kato M, Hanao M, Hamamoto H, Sekimizu K, Okazaki M. Evaluation of pathogenicity and therapeutic effectiveness of antibiotics using silkworm Nocardia infection model. Drug Discov Ther 2021; 15:73-77. [PMID: 33952779 DOI: 10.5582/ddt.2021.01035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Nocardia is a ubiquitous environmental microbe that causes nocardiosis against immunosuppressed and immunocompromised hosts. The assay system for the quantitative evaluation of virulence of Nocardia sp. or therapeutic effectiveness of antimicrobials for treatment of nocardiosis is not established so far. In this study, we established an infection model of Nocardia sp. using silkworm as an alternative animal model. We found that all tested Nocardia sp. such as Nocardia asiatica, Nocardia elegans, Nocardia exalbida, Nocardia farcinica, and Nocardia nova killed silkworm and their killing ability were different by species. N. farcinica showed higher pathogenicity among tested strain, similar to the mouse model as previously reported. In addition, we found that antimicrobials such as amikacin and minocycline showed therapeutic effectiveness in silkworms infected with N. farcinica, and we could determine effective doses 50 (ED₅₀) values. These results suggest that silkworm is a useful alternative animal to evaluate the pathogenicity of Nocardia pathogen and the therapeutic effects of antimicrobials against Nocardia sp. in a quantitative manner.
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Affiliation(s)
- Kazuhiro Mikami
- Department of Medical Technology, School of Health Sciences, Tokyo University of Technology, Tokyo, Japan.,Drug Discoveries by Silkworm Models, Faculty of Pharma-Science, Teikyo University, Tokyo, Japan
| | - Kazunari Sonobe
- Department of Clinical Laboratory, Tokyo Medical and Dental University Medical Hospital, Tokyo, Japan
| | - Keiko Ishino
- Division of Infection Control Sciences, Department of Clinical Pharmacy, School of Pharmacy, Showa University, Tokyo, Japan
| | - Takumi Noda
- Department of Medical Technology, School of Health Sciences, Tokyo University of Technology, Tokyo, Japan
| | - Mami Kato
- Department of Medical Technology, School of Health Sciences, Tokyo University of Technology, Tokyo, Japan
| | - Mami Hanao
- Department of Medical Technology, School of Health Sciences, Tokyo University of Technology, Tokyo, Japan
| | | | - Kazuhisa Sekimizu
- Drug Discoveries by Silkworm Models, Faculty of Pharma-Science, Teikyo University, Tokyo, Japan.,Genome Pharmaceuticals Institute, Tokyo, Japan
| | - Mitsuhiro Okazaki
- Department of Medical Technology, School of Health Sciences, Tokyo University of Technology, Tokyo, Japan
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Pierzynowska K, Skowron Volponi M, Węgrzyn G. Multiple factors correlating with wing malformations in the population of Parnassius apollo (Lepidoptera: Papilionidae) restituted from a low number of individuals: A mini review. INSECT SCIENCE 2019; 26:380-387. [PMID: 29094498 DOI: 10.1111/1744-7917.12554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 09/22/2017] [Accepted: 10/10/2017] [Indexed: 06/07/2023]
Abstract
The Apollo butterfly, Parnassius apollo (Linnaeus), was common in Europe over 100 years ago, but currently it is considered as near threatened. Different conservation programs have promoted the persistence of this species; however, it is still endangered. An example of such programs was the action devoted to reestablish the Apollo butterfly population in Pieniny National Park (Poland) from only 20-30 individuals which had survived till the last decade of the 20th century. This reintroduction has been successful; however, unexpected developmental problems appeared. Butterflies with deformed or reduced wings became frequent in the population living in the natural habitat, and particularly among those reared under seminatural conditions (in the same environment, but fenced by a net). Until recently, reasons for these malformations remained unknown. However, reports published during last months indicated that there are genetic, biochemical, and microbiological factors contributing to this phenomenon. In the malformed individuals, lesions in the wingless gene and dysfunctions of laccase 1 and 2 were found to be significantly more frequent than in normal insects. A large fraction of butterflies with deformed or reduced wings was devoid of the prokaryotic symbiont Wolbachia, which was present in most normal individuals. Moreover, Yersinia pseudotuberculosis (Pfeiffer) Smith and Thal, and Serratia sp., bacteria pathogenic to insects, were detected in the biological material from both normal and malformed butterflies from this population. These findings are summarized and discussed in this review, in the light of conservation of insects and restitution of their populations from a low number of individuals.
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Affiliation(s)
| | | | - Grzegorz Węgrzyn
- Department of Molecular Biology, University of Gdańsk, Gdańsk, Poland
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15
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Ma L, Zhou L, Lin J, Ji J, Wang Y, Jiang H, Shen X, Lu Z. Manipulation of the silkworm immune system by a metalloprotease from the pathogenic bacterium Pseudomonas aeruginosa. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2019; 90:176-185. [PMID: 30261235 PMCID: PMC6204220 DOI: 10.1016/j.dci.2018.09.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Revised: 09/22/2018] [Accepted: 09/23/2018] [Indexed: 05/15/2023]
Abstract
Antimicrobial peptide (AMP) production and melanization are two key humoral immune responses in insects. Induced synthesis of AMPs results from Toll and IMD signal transduction whereas melanization depends on prophenoloxidase (PPO) activation system. During invasion, pathogens produce toxins and other virulent factors to counteract host immune responses. Here we show that the pathways leading to PPO activation and AMP synthesis in the silkworm Bombyx mori are affected by a metalloprotease, named elastase B, secreted by Pseudomonas aeruginosa (PAO1). The metalloprotease gene (lasB) was expressed shortly after PAO1 cells had been injected into the larval silkworm hemocoel, leading to an increase of elastase activity. Injection of the purified PAO1 elastase B into silkworm hemolymph compromised PPO activation. In contrast, the protease caused a level increase of gloverin, an AMP in the hemolymph. To verify our results obtained using the purified elastase B, we infected B. mori with PAO1 ΔlasB mutant and found that PO activity in hemolymph of the PAO1 ΔlasB-infected larvae was significantly higher than that in the wild type-infected. The mutant-inhabited hemolymph had lower levels of gloverin and antimicrobial activity. PAO1 ΔlasB showed a decreased viability in the silkworm hemolymph whereas the host had a lower mortality. In addition, the effects caused by the ΔlasB mutant were restored by a complementary strain. These data collectively indicated that the elastase B produced by PAO1 is an important virulent factor that manipulates the silkworm immune system during infection.
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Affiliation(s)
- Li Ma
- Department of Entomology, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Lizhen Zhou
- Department of Entomology, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Jinshui Lin
- Department of Microbiology, College of Life Science, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Jiuyuan Ji
- Department of Entomology, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Yang Wang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Haobo Jiang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Xihui Shen
- Department of Microbiology, College of Life Science, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Zhiqiang Lu
- Department of Entomology, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China.
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Niu H, Wang N, Liu B, Xiao L, Wang L, Guo H. Synergistic and additive interactions of Serratia marcescens S-JS1 to the chemical insecticides for controlling Nilaparvata lugens (Hemiptera: Delphacidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2018; 111:823-828. [PMID: 29385504 DOI: 10.1093/jee/tox348] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Indexed: 06/07/2023]
Abstract
The combined use of entomopathogens and chemical agents has been suggested as an alternative strategy to control pest insects. However, the effectiveness of combinations of entomopathogenic bacteria and insecticides against rice planthoppers is largely unknown. Here, we evaluated the separate and combined effects of an entomopathogenic bacterium, Serratia marcescens S-JS1, and spirotetramat or thiamethoxam insecticides against third-instar nymphs of Nilaparvata lugens Stål (Hemiptera: Delphacidae) under laboratory and greenhouse conditions. Under laboratory conditions, the combinations caused higher mortality in the third-instar nymphs of N. lugens and produced a synergistic or additive effect compared with the treatments with either bacterial suspension or insecticide alone. Application of S-JS1 (1 × 109 cfu/ml) in combination with 20 mg/liter spirotetramat resulted in 80.5% of N. lugens nymphal mortality, compared with 52.7% in spirotetramat alone treatments, and interactions resulted in a synergistic responses. Other combination treatments of S-JS1 with either insecticide concentration all exhibited additive interactions. In further greenhouse tests, S-JS1 (1 × 109 cfu/ml) + spirotetramat (20 mg/liter) and S-JS1 (1 × 109 cfu/ml) + thiamethoxam (5 mg/liter) showed additive effects against the nymphs, and were found to be most effective relative to their individual treatments on days 5 and 9. Our results indicate that S. marcescens S-JS1 combined with insecticide may provide a promising new strategy for controlling N. lugens.
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Affiliation(s)
- Hongtao Niu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Na Wang
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Baosheng Liu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Lijunjie Xiao
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Lihua Wang
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Huifang Guo
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
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Lee SA, Jang SH, Kim BH, Shibata T, Yoo J, Jung Y, Kawabata SI, Lee BL. Insecticidal activity of the metalloprotease AprA occurs through suppression of host cellular and humoral immunity. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 81:116-126. [PMID: 29174605 DOI: 10.1016/j.dci.2017.11.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 11/22/2017] [Accepted: 11/22/2017] [Indexed: 06/07/2023]
Abstract
The biochemical characterization of virulence factors from entomopathogenic bacteria is important to understand entomopathogen-insect molecular interactions. Pseudomonas entomophila is a typical entomopathogenic bacterium that harbors virulence factors against several insects. However, the molecular actions of these factors against host innate immune responses are not clearly elucidated. In this study, we observed that bean bugs (Riptortus pedestris) that were injected with P. entomophila were highly susceptible to this bacterium. To determine how P. entomophila counteracts the host innate immunity to survive within the insect, we purified a highly enriched protein with potential host insect-killing activity from the culture supernatant of P. entomophila. Then, a 45-kDa protein was purified to homogeneity and identified as AprA which is an alkaline zinc metalloprotease of the genus Pseudomonas by liquid chromatography mass spectrometry (LC-MS). Purified AprA showed a pronounced killing effect against host insects and suppressed both host cellular and humoral innate immunity. Furthermore, to show that AprA is an important insecticidal protein of P. entomophila, we used an aprA-deficient P. entomophila mutant strain (ΔaprA). When ΔaprA mutant cells were injected to host insects, this mutant exhibited extremely attenuated virulence. In addition, the cytotoxicity against host hemocytes and the antimicrobial peptide-degrading ability of the ΔaprA mutant were greatly decreased. These findings suggest that AprA functions as an important insecticidal protein of P. entomophila via suppression of host cellular and humoral innate immune responses.
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Affiliation(s)
- Seung Ah Lee
- Global Research Laboratory of Insect Symbiosis, Pusan National University, Busan 46241, South Korea
| | - Seong Han Jang
- Global Research Laboratory of Insect Symbiosis, Pusan National University, Busan 46241, South Korea
| | - Byung Hyun Kim
- Global Research Laboratory of Insect Symbiosis, Pusan National University, Busan 46241, South Korea
| | - Toshio Shibata
- Institute for Advanced Study, Kyushu University, Fukuoka 819-0395, Japan; Graduate School of Systems Life Sciences, Kyushu University, Fukuoka 819-0395, Japan
| | - Jinwook Yoo
- College of Pharmacy, Pusan National University, Busan 46241, South Korea
| | - Yunjin Jung
- College of Pharmacy, Pusan National University, Busan 46241, South Korea
| | - Shun-Ichiro Kawabata
- Institute for Advanced Study, Kyushu University, Fukuoka 819-0395, Japan; Graduate School of Systems Life Sciences, Kyushu University, Fukuoka 819-0395, Japan
| | - Bok Luel Lee
- Global Research Laboratory of Insect Symbiosis, Pusan National University, Busan 46241, South Korea.
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CpxR-Dependent Thermoregulation of Serratia marcescens PrtA Metalloprotease Expression and Its Contribution to Bacterial Biofilm Formation. J Bacteriol 2018; 200:JB.00006-18. [PMID: 29378892 DOI: 10.1128/jb.00006-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 01/20/2018] [Indexed: 12/19/2022] Open
Abstract
PrtA is the major secreted metalloprotease of Serratia marcescens Previous reports implicate PrtA in the pathogenic capacity of this bacterium. PrtA is also clinically used as a potent analgesic and anti-inflammatory drug, and its catalytic properties attract industrial interest. Comparatively, there is scarce knowledge about the mechanisms that physiologically govern PrtA expression in Serratia In this work, we demonstrate that PrtA production is derepressed when the bacterial growth temperature decreases from 37°C to 30°C. We show that this thermoregulation occurs at the transcriptional level. We determined that upstream of prtA, there is a conserved motif that is directly recognized by the CpxR transcriptional regulator. This feature is found along Serratia strains irrespective of their isolation source, suggesting an evolutionary conservation of CpxR-dependent regulation of PrtA expression. We found that in S. marcescens, the CpxAR system is more active at 37°C than at 30°C. In good agreement with these results, in a cpxR mutant background, prtA is derepressed at 37°C, while overexpression of the NlpE lipoprotein, a well-known CpxAR-inducing condition, inhibits PrtA expression, suggesting that the levels of the activated form of CpxR are increased at 37°C over those at 30°C. In addition, we establish that PrtA is involved in the ability of S. marcescens to develop biofilm. In accordance, CpxR influences the biofilm phenotype only when bacteria are grown at 37°C. In sum, our findings shed light on regulatory mechanisms that fine-tune PrtA expression and reveal a novel role for PrtA in the lifestyle of S. marcescensIMPORTANCE We demonstrate that S. marcescens metalloprotease PrtA expression is transcriptionally thermoregulated. While strongly activated below 30°C, its expression is downregulated at 37°C. We found that in S. marcescens, the CpxAR signal transduction system, which responds to envelope stress and bacterial surface adhesion, is activated at 37°C and able to downregulate PrtA expression by direct interaction of CpxR with a binding motif located upstream of the prtA gene. Moreover, we reveal that PrtA expression favors the ability of S. marcescens to develop biofilm, irrespective of the bacterial growth temperature. In this context, thermoregulation along with a highly conserved CpxR-dependent modulation mechanism gives clues about the relevance of PrtA as a factor implicated in the persistence of S. marcescens on abiotic surfaces and in bacterial host colonization capacity.
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Srinivasan R, Mohankumar R, Kannappan A, Karthick Raja V, Archunan G, Karutha Pandian S, Ruckmani K, Veera Ravi A. Exploring the Anti-quorum Sensing and Antibiofilm Efficacy of Phytol against Serratia marcescens Associated Acute Pyelonephritis Infection in Wistar Rats. Front Cell Infect Microbiol 2017; 7:498. [PMID: 29259923 PMCID: PMC5723315 DOI: 10.3389/fcimb.2017.00498] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 11/20/2017] [Indexed: 01/15/2023] Open
Abstract
Quorum Sensing (QS) mechanism, a bacterial density-dependent gene expression system, governs the Serratia marcescens pathogenesis through the production of virulence factors and biofilm formation. The present study demonstrates the anti-quorum sensing (anti-QS), antibiofilm potential and in vivo protective effect of phytol, a diterpene alcohol broadly utilized as food additive and in therapeutics fields. In vitro treatment of phytol (5 and 10 μg/ml) showed decreasing level of biofilm formation, lipase and hemolysin production in S. marcescens compared to their respective controls. More, microscopic analyses confirmed the antibiofilm potential of phytol. The biofilm related phenomenons such as swarming motility and exopolysccharide productions were also inhibited by phytol. Furthermore, the real-time analysis elucidated the molecular mechanism of phytol which showed downregulation of fimA, fimC, flhC, flhD, bsmB, pigP, and shlA gene expressions. On the other hand, the in vivo rescue effect of phytol was assessed against S. marcescens associated acute pyelonephritis in Wistar rat. Compared to the infected and vehicle controls, the phytol treated groups (100 and 200 mg/kg) showed decreased level of bacterial counts in kidney, bladder tissues and urine samples on the 5th post infection day. As well, the phytol treatment showed reduced level of virulence enzymes such as lipase and protease productions compared to the infected and vehicle controls. Further, the infected and vehicle controls showed increasing level of inflammatory markers such as malondialdehyde (MDA), nitric oxide (NO) and myeloperoxidase (MPO) productions. In contrast, the phytol treatment showed decreasing level of inflammatory markers. In histopathology, the uninfected animal showed normal kidney and bladder structure, wherein, the infected animals showed extensive infiltration of neutrophils in kidney and bladder tissues. In contrast, the phytol treatment showed normal kidney and bladder tissues. Additionally, the toxic effect of phytol (200 mg/kg) was assessed by single dose toxicity analysis. No changes were observed in hematological, biochemical profiles and histopathological analysis of vital organs in phytol treated animals compared to the untreated controls. Hence, this study suggested the potential use of phytol for its anti-QS, antibiofilm and anti-inflammatory properties against S. marcescens infections and their associated inflammation reactions.
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Affiliation(s)
| | - Ramar Mohankumar
- Department of Pharmaceutical Technology, National Facility for Drug Development for Academia, Pharmaceutical and Allied Industries, Bharathidasan Institute of Technology, Anna University, Tiruchirappalli, India
| | | | | | - Govindaraju Archunan
- Department of Animal Science, Centre for Pheromone Technology, Bharathidasan University, Tiruchirappalli, India
| | | | - Kandasamy Ruckmani
- Department of Pharmaceutical Technology, National Facility for Drug Development for Academia, Pharmaceutical and Allied Industries, Bharathidasan Institute of Technology, Anna University, Tiruchirappalli, India
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Stella NA, Callaghan JD, Zhang L, Brothers KM, Kowalski RP, Huang JJ, Thibodeau PH, Shanks RMQ. SlpE is a calcium-dependent cytotoxic metalloprotease associated with clinical isolates of Serratia marcescens. Res Microbiol 2017; 168:567-574. [PMID: 28366837 PMCID: PMC5503780 DOI: 10.1016/j.resmic.2017.03.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 03/08/2017] [Accepted: 03/22/2017] [Indexed: 01/15/2023]
Abstract
Serralysin-like proteases are found in a wide variety of bacteria. These metalloproteases are frequently implicated in virulence and are members of the widely conserved RTX-toxin family. We identified a serralysin-like protease in the genome of a clinical isolate of Serratia marcescens that is highly similar to the canonical serralysin protein, PrtS. This gene was named serralysin-like protease E, SlpE, and was found in the majority (67%) of tested clinical isolates, but was absent from most tested non-clinical isolates including the insect pathogen and reference S. marcescens strain Db11. Purified recombinant SlpE exhibited calcium-dependent protease activity similar to metalloproteases PrtS and SlpB. Induction of slpE in the low-protease-producing S. marcescens strain PIC3611 highly elevated extracellular protease activity, and extracellular secretion required the lipD type 1 secretion system gene. Transcription of slpE was highly reduced in an eepR transcription factor mutant. Mutation of the slpE gene in a highly proteolytic clinical isolate reduced its protease activity, and evidence suggests that SlpE confers cytotoxicity of S. marcescens to the A549 airway carcinoma cell line. Together, these data reveal SlpE to be an EepR-regulated cytotoxic metalloprotease associated with clinical isolates of an important opportunistic pathogen.
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Affiliation(s)
- Nicholas A Stella
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Jake D Callaghan
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Liang Zhang
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Kimberly M Brothers
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Regis P Kowalski
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Jean J Huang
- Department of Biology, Olin College, Needham, MA 02492, USA
| | - Patrick H Thibodeau
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Robert M Q Shanks
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA 15213, USA; Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, USA.
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21
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Machado SG, Baglinière F, Marchand S, Van Coillie E, Vanetti MCD, De Block J, Heyndrickx M. The Biodiversity of the Microbiota Producing Heat-Resistant Enzymes Responsible for Spoilage in Processed Bovine Milk and Dairy Products. Front Microbiol 2017; 8:302. [PMID: 28298906 PMCID: PMC5331058 DOI: 10.3389/fmicb.2017.00302] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 02/14/2017] [Indexed: 12/28/2022] Open
Abstract
Raw bovine milk is highly nutritious as well as pH-neutral, providing the ideal conditions for microbial growth. The microbiota of raw milk is diverse and originates from several sources of contamination including the external udder surface, milking equipment, air, water, feed, grass, feces, and soil. Many bacterial and fungal species can be found in raw milk. The autochthonous microbiota of raw milk immediately after milking generally comprises lactic acid bacteria such as Lactococcus, Lactobacillus, Streptococcus, and Leuconostoc species, which are technologically important for the dairy industry, although they do occasionally cause spoilage of dairy products. Differences in milking practices and storage conditions on each continent, country and region result in variable microbial population structures in raw milk. Raw milk is usually stored at cold temperatures, e.g., about 4°C before processing to reduce the growth of most bacteria. However, psychrotrophic bacteria can proliferate and contribute to spoilage of ultra-high temperature (UHT) treated and sterilized milk and other dairy products with a long shelf life due to their ability to produce extracellular heat resistant enzymes such as peptidases and lipases. Worldwide, species of Pseudomonas, with the ability to produce these spoilage enzymes, are the most common contaminants isolated from cold raw milk although other genera such as Serratia are also reported as important milk spoilers, while for others more research is needed on the heat resistance of the spoilage enzymes produced. The residual activity of extracellular enzymes after high heat treatment may lead to technological problems (off flavors, physico-chemical instability) during the shelf life of milk and dairy products. This review covers the contamination patterns of cold raw milk in several parts of the world, the growth potential of psychrotrophic bacteria, their ability to produce extracellular heat-resistant enzymes and the consequences for dairy products with a long shelf life. This problem is of increasing importance because of the large worldwide trade in fluid milk and milk powder.
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Affiliation(s)
- Solimar G Machado
- Instituto Federal do Norte de Minas Gerais - Campus Salinas Salinas, Brazil
| | | | - Sophie Marchand
- Technology and Food Science Unit, Flanders Research Institute for Agriculture, Fischeries and Food (ILVO) Melle, Belgium
| | - Els Van Coillie
- Technology and Food Science Unit, Flanders Research Institute for Agriculture, Fischeries and Food (ILVO) Melle, Belgium
| | - Maria C D Vanetti
- Department of Microbiology, Universidade Federal de Viçosa Viçosa, Brazil
| | - Jan De Block
- Technology and Food Science Unit, Flanders Research Institute for Agriculture, Fischeries and Food (ILVO) Melle, Belgium
| | - Marc Heyndrickx
- Technology and Food Science Unit, Flanders Research Institute for Agriculture, Fischeries and Food (ILVO)Melle, Belgium; Department of Pathology, Bacteriology and Poultry Diseases, Ghent UniversityMerelbeke, Belgium
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22
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Lee DJ, Lee JB, Jang HA, Ferrandon D, Lee BL. An antimicrobial protein of the Riptortus pedestris salivary gland was cleaved by a virulence factor of Serratia marcescens. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2017; 67:427-433. [PMID: 27555079 DOI: 10.1016/j.dci.2016.08.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 08/17/2016] [Accepted: 08/18/2016] [Indexed: 06/06/2023]
Abstract
Recently, our group demonstrated that the bean bug, Riptortus pedestris, is a good experimental symbiosis model to study the molecular cross-talk between the host insect and the gut symbiont. The Burkholderia symbiont is orally acquired by host nymphs from the environment in every generation. However, it is still unclear how Riptortus specifically interacts with entomopathogens that are abundant in the environmental soil. In preliminary experiments, we observed that a potent entomopathogen, Serratia marcescens, can colonize the midgut of Riptortus insects and was recovered from the midgut when Serratia cells were orally administered, suggesting that this pathogenic bacterium can escape host immune defenses in the salivary fluid. We examined how orally fed Serratia cells can survive in the presence of antimicrobial substances of the Riptortus salivary fluid. In this study, a 15 kDa trialysin-like protein from the salivary gland of R. pedestris and a potent virulence factor of Serratia cells, a serralysin metalloprotease, from the culture medium of S. marcescens were successfully purified to homogeneity. When the purified Riptortus trialysin (rip-trialysin) was incubated with purified serralysin, rip-trialysin was specifically hydrolyzed by serralysin, leading to the loss of antimicrobial activity. These results clearly demonstrated that a potent virulent metalloprotease of S. marcescens functions as a key player in the escape from the salivary fluid-mediated host immune response, resulting in successful colonization of S. marcescens in the host midgut.
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Affiliation(s)
- Dong Jung Lee
- Global Research Laboratory, College of Pharmacy, Pusan National University, Busan 46241, South Korea
| | - Jun Beom Lee
- Global Research Laboratory, College of Pharmacy, Pusan National University, Busan 46241, South Korea
| | - Ho Am Jang
- Global Research Laboratory, College of Pharmacy, Pusan National University, Busan 46241, South Korea
| | - Dominique Ferrandon
- Equipe Fondation Recherche Médicale, UPR 9022 du CNRS, Institut de Biologie Moleculaire et Cellulaire du CNRS, Strasbourg, France
| | - Bok Luel Lee
- Global Research Laboratory, College of Pharmacy, Pusan National University, Busan 46241, South Korea.
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23
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Flury P, Aellen N, Ruffner B, Péchy-Tarr M, Fataar S, Metla Z, Dominguez-Ferreras A, Bloemberg G, Frey J, Goesmann A, Raaijmakers JM, Duffy B, Höfte M, Blom J, Smits THM, Keel C, Maurhofer M. Insect pathogenicity in plant-beneficial pseudomonads: phylogenetic distribution and comparative genomics. THE ISME JOURNAL 2016; 10:2527-42. [PMID: 26894448 PMCID: PMC5030700 DOI: 10.1038/ismej.2016.5] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Revised: 12/09/2015] [Accepted: 12/22/2015] [Indexed: 11/09/2022]
Abstract
Bacteria of the genus Pseudomonas occupy diverse environments. The Pseudomonas fluorescens group is particularly well-known for its plant-beneficial properties including pathogen suppression. Recent observations that some strains of this group also cause lethal infections in insect larvae, however, point to a more versatile ecology of these bacteria. We show that 26 P. fluorescens group strains, isolated from three continents and covering three phylogenetically distinct sub-clades, exhibited different activities toward lepidopteran larvae, ranging from lethal to avirulent. All strains of sub-clade 1, which includes Pseudomonas chlororaphis and Pseudomonas protegens, were highly insecticidal regardless of their origin (animals, plants). Comparative genomics revealed that strains in this sub-clade possess specific traits allowing a switch between plant- and insect-associated lifestyles. We identified 90 genes unique to all highly insecticidal strains (sub-clade 1) and 117 genes common to all strains of sub-clade 1 and present in some moderately insecticidal strains of sub-clade 3. Mutational analysis of selected genes revealed the importance of chitinase C and phospholipase C in insect pathogenicity. The study provides insight into the genetic basis and phylogenetic distribution of traits defining insecticidal activity in plant-beneficial pseudomonads. Strains with potent dual activity against plant pathogens and herbivorous insects have great potential for use in integrated pest management for crops.
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Affiliation(s)
- Pascale Flury
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Nora Aellen
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Beat Ruffner
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Maria Péchy-Tarr
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Shakira Fataar
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Zane Metla
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
- Laboratory of Experimental Entomology, Institute of Biology, University of Latvia, Riga, Latvia
| | | | - Guido Bloemberg
- Institute of Medical Microbiology, University of Zurich, Zürich, Switzerland
| | - Joachim Frey
- Institute of Veterinary Bacteriology, University of Bern, Bern, Switzerland
| | - Alexander Goesmann
- Bioinformatics and Systems Biology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Jos M Raaijmakers
- Department of Microbial Ecology, Netherlands Institute of Ecology, NIOO-KNAW, Wageningen, The Netherlands
| | - Brion Duffy
- Environmental Genomics and Systems Biology Research Group, Institute for Natural Resource Sciences, Zürich University of Applied Sciences, Wädenswil, Switzerland
| | - Monica Höfte
- Laboratory of Phytopathology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Jochen Blom
- Bioinformatics and Systems Biology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Theo H M Smits
- Environmental Genomics and Systems Biology Research Group, Institute for Natural Resource Sciences, Zürich University of Applied Sciences, Wädenswil, Switzerland
| | - Christoph Keel
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Monika Maurhofer
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
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24
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Hurst MRH, Beattie A, Altermann E, Moraga RM, Harper LA, Calder J, Laugraud A. The Draft Genome Sequence of the Yersinia entomophaga Entomopathogenic Type Strain MH96T. Toxins (Basel) 2016; 8:toxins8050143. [PMID: 27187466 PMCID: PMC4885058 DOI: 10.3390/toxins8050143] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 04/21/2016] [Accepted: 04/26/2016] [Indexed: 01/28/2023] Open
Abstract
Here we report the draft genome of Yersinia entomophaga type strain MH96T. The genome shows 93.8% nucleotide sequence identity to that of Yersinia nurmii type strain APN3a-cT, and comprises a single chromosome of approximately 4,275,531 bp. In silico analysis identified that, in addition to the previously documented Y. entomophaga Yen-TC gene cluster, the genome encodes a diverse array of toxins, including two type III secretion systems, and five rhs-associated gene clusters. As well as these multicomponent systems, several orthologs of known insect toxins, such as VIP2 toxin and the binary toxin PirAB, and distant orthologs of some mammalian toxins, including repeats-in-toxin, a cytolethal distending toxin, hemolysin-like genes and an adenylate cyclase were identified. The genome also contains a large number of hypothetical proteins and orthologs of known effector proteins, such as LopT, as well as genes encoding a wide range of proteolytic determinants, including metalloproteases and pathogen fitness determinants, such as genes involved in iron metabolism. The bioinformatic data derived from the current in silico analysis, along with previous information on the pathobiology of Y. entomophaga against its insect hosts, suggests that a number of these virulence systems are required for survival in the hemocoel and incapacitation of the insect host.
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Affiliation(s)
- Mark R H Hurst
- AgResearch, Farm Systems & Environment, Lincoln Research Centre, Christchurch 8140, New Zealand.
| | - Amy Beattie
- AgResearch, Farm Systems & Environment, Lincoln Research Centre, Christchurch 8140, New Zealand.
| | - Eric Altermann
- AgResearch Limited, Rumen Microbiology, Palmerston North 4474, New Zealand.
- Riddet Institute, Massey University, Palmerston North 4474, New Zealand.
| | - Roger M Moraga
- AgResearch Limited, Bioinformatics & Statistics, Hamilton 3214, New Zealand.
| | - Lincoln A Harper
- AgResearch, Farm Systems & Environment, Lincoln Research Centre, Christchurch 8140, New Zealand.
| | - Joanne Calder
- AgResearch, Farm Systems & Environment, Lincoln Research Centre, Christchurch 8140, New Zealand.
| | - Aurelie Laugraud
- AgResearch Limited, Bioinformatics & Statistics, Lincoln Research Centre, Christchurch 8140, New Zealand.
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25
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Zhou W, Li J, Chen J, Liu X, Xiang T, Zhang L, Wan Y. The red pigment prodigiosin is not an essential virulence factor in entomopathogenic Serratia marcescens. J Invertebr Pathol 2016; 136:92-4. [DOI: 10.1016/j.jip.2016.03.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 03/15/2016] [Accepted: 03/16/2016] [Indexed: 10/22/2022]
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26
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EepR Mediates Secreted-Protein Production, Desiccation Survival, and Proliferation in a Corneal Infection Model. Infect Immun 2015; 83:4373-82. [PMID: 26324535 DOI: 10.1128/iai.00466-15] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 08/25/2015] [Indexed: 02/08/2023] Open
Abstract
Serratia marcescens is a soil- and water-derived bacterium that secretes several host-directed factors and causes hospital infections and community-acquired ocular infections. The putative two-component regulatory system composed of EepR and EepS regulates hemolysis and swarming motility through transcriptional control of the swrW gene and pigment production through control of the pigA-pigN operon. Here, we identify and characterize a role for EepR in regulation of exoenzyme production, stress survival, cytotoxicity to human epithelial cells, and virulence. Genetic analysis supports the model that EepR is in a common pathway with the widely conserved cyclic-AMP receptor protein that regulates protease production. Together, these data introduce a novel regulator of host-pathogen interactions and secreted-protein production.
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27
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Draft Whole-Genome Sequence of Serratia sp. Strain TEL, Associated with Oscheius sp. TEL-2014 (Nematoda: Rhabditidae) Isolated from a Grassland in South Africa. GENOME ANNOUNCEMENTS 2015; 3:3/4/e00747-15. [PMID: 26159531 PMCID: PMC4498117 DOI: 10.1128/genomea.00747-15] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Here, we report on the draft genome sequence of Serratia sp. strain TEL, associated with Oscheius sp. TEL-2014 (Nematoda: Rhabditidae, KM492926) isolated from a grassland in Suikerbosrand Nature Reserve near Johannesburg in South Africa. Serratia sp. strain TEL has a genome size of 5,000,541 bp with 4,647 genes and a G+C content of 59.1%.
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28
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Ishii K, Hamamoto H, Sekimizu K. Studies of host-pathogen interactions and immune-related drug development using the silkworm: interdisciplinary immunology, microbiology, and pharmacology studies. Drug Discov Ther 2015; 9:238-46. [PMID: 25865526 DOI: 10.5582/ddt.2015.01015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Innate immunity acts as a front-line barrier against invading pathogens, and the majority of the components are widely conserved among species. Regulation of innate immunity is important for overcoming infections and preventing self-damaging sepsis. Using the silkworm (Bombyx mori) as an animal model, we elucidated the activation processes of innate immunity with emphasis on a multifunctional insect cytokine called paralytic peptide. Moreover, we established an ex vivo system using silkworm larval specimens to quantitatively evaluate the immunostimulatory activity of natural compounds. We observed that overactivation of innate immunity in silkworms induces tissue damage followed by host death, resembling sepsis-induced multi-organ failure in humans. Here, we summarize our recent findings and propose the usefulness of the silkworm as an animal model for studying immune regulation and for evaluating compounds with the potential to regulate innate immunity.
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Affiliation(s)
- Kenichi Ishii
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo
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