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Open AccessArticle

Towards A Novel Multi-Epitopes Chimeric Vaccine for Simulating Strong Immune Responses and Protection against Morganella morganii

by Asad Ullah, Sajjad Ahmad, Saba Ismail, Zobia Afsheen, Muhammad Khurram, Muhammad Tahir ul Qamar, Naif AlSuhaymi, Mahdi H. Alsugoor and Khaled S. Allemailem

Int. J. Environ. Res. Public Health 2021, 18(20), 10961; https://doi.org/10.3390/ijerph182010961 - 19 Oct 2021

Cited by 40 | Viewed by 4493

Abstract

Morganella morganii is one of the main etiological agents of hospital-acquired infections and no licensed vaccine is available against the pathogen. Herein, we designed a multi-epitope-based vaccine against M. morganii. Predicted proteins from fully sequenced genomes of the pathogen were subjected to a core sequences analysis, followed by the prioritization of non-redundant, host non-homologous and extracellular, outer membrane and periplasmic membrane virulent proteins as vaccine targets. Five proteins (TonB-dependent siderophore receptor, serralysin family metalloprotease, type 1 fimbrial protein, flagellar hook protein (FlgE), and pilus periplasmic chaperone) were shortlisted for the epitope prediction. The predicted epitopes were checked for antigenicity, toxicity, solubility, and binding affinity with the DRB*0101 allele. The selected epitopes were linked with each other through GPGPG linkers and were joined with the cholera toxin B subunit (CTBS) to boost immune responses. The tertiary structure of the vaccine was modeled and blindly docked with MHC-I, MHC-II, and Toll-like receptors 4 (TLR4). Molecular dynamic simulations of 250 nanoseconds affirmed that the designed vaccine showed stable conformation with the receptors. Further, intermolecular binding free energies demonstrated the domination of both the van der Waals and electrostatic energies. Overall, the results of the current study might help experimentalists to develop a novel vaccine against M. morganii. Full article

(This article belongs to the Collection Vaccination Research for Public Health)

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10 pages, 1558 KB

Open AccessArticle

The Role of SprIR Quorum Sensing System in the Regulation of Serratia proteamaculans 94 Invasion

by Olga Tsaplina, Inessa Khmel, Yulia Zaitseva and Sofia Khaitlina

Microorganisms 2021, 9(10), 2082; https://doi.org/10.3390/microorganisms9102082 - 2 Oct 2021

Cited by 4 | Viewed by 2794

Abstract

The bacteria Serratia proteamaculans 94 have a LuxI/LuxR type QS system consisting of AHL synthase SprI and the regulatory receptor SprR. We have previously shown that inactivation of the AHL synthase sprI gene resulted in an increase in the invasive activity of S. proteamaculans correlated with an increased bacterial adhesion. In the present work, the effects of inactivation of the S. proteamaculans receptor SprR are studied. Our results show that inactivation of the receptor sprR gene leads to an increase in bacterial invasion without any increase in their adhesion. On the other hand, inactivation of the sprR gene increases the activity of the extracellular protease serralysin. Inactivation of the QS system does not affect the activity of the pore-forming toxin ShlA and prevents the ShlA activation under conditions of a limited concentration of iron ions typical of the human body. While the wild type strain shows increased invasion in the iron-depleted medium, deletion of its QS system leads to a decrease in host cell invasion, which is nevertheless similar to the level of the wild type S. proteamaculans grown in the iron-rich medium. Thus, inactivation of either of the two component of the S. proteamaculans LuxI/LuxR-type QS system leads to an increase in the invasive activity of these bacteria through different mechanisms and prevents invasion under the iron-limited conditions. Full article

(This article belongs to the Section Molecular Microbiology and Immunology)

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19 pages, 1218 KB

Open AccessArticle

Pathogenicity of Isolates of Serratia Marcescens towards Larvae of the Scarab Phyllophaga Blanchardi (Coleoptera)

by Mónica L. Pineda-Castellanos, Zitlhally Rodríguez-Segura, Francisco J. Villalobos, Luciano Hernández, Laura Lina and M. Eugenia Nuñez-Valdez

Pathogens 2015, 4(2), 210-228; https://doi.org/10.3390/pathogens4020210 - 13 May 2015

Cited by 51 | Viewed by 10168

Abstract

Serratia marcescens is a Gram negative bacterium (Enterobacteriaceae) often associated with infection of insects. In order to find pathogenic bacteria with the potential to control scarab larvae, several bacterial strains were isolated from the hemocoel of diseased Phyllophaga spp (Coleoptera:Scarabaeidae) larvae collected from cornfields in Mexico. Five isolates were identified as Serratia marcescens by 16S rRNA gene sequencing and biochemical tests. Oral and injection bioassays using healthy Phyllophaga blanchardi larvae fed with the S. marcescens isolates showed different degrees of antifeeding effect and mortality. No insecticidal activity was observed for Spodoptera frugiperda larvae (Lepidoptera: Noctuidae) by oral inoculation. S. marcescens (Sm81) cell-free culture supernatant caused significant antifeeding effect and mortality to P. blanchardi larvae by oral bioassay and also mortality by injection bioassay. Heat treated culture broths lost the ability to cause disease symptoms, suggesting the involvement of proteins in the toxic activity. A protein of 50.2 kDa was purified from the cell-free broth and showed insecticidal activity by injection bioassay towards P. blanchardi. Analysis of the insecticidal protein by tandem- mass spectrometry (LC-MS/MS) showed similarity to a Serralysin-like protein from S. marcescens spp. This insecticidal protein could have applications in agricultural biotechnology. Full article

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