In silico analysis of Brucella abortus Omp2b and in vitro expression of SOmp2b

Potential Piperolactam A Isolated From Piper betle as Natural Inhibitors of Brucella Species Aminoacyl-tRNA Synthetase for Livestock Infections: In Silico Approach

Brucellosis is an important global zoonosis caused by the bacterium Brucella sp. Brucellosis causes abortions, reproductive failure and reduced milk production, resulting in significant economic losses. Brucella species are reported to be resistant to antibiotics, which makes treatment difficult. The urgency of discovering new drug candidates to combat Brucella's infection necessitates the exploration of novel alternative agents with unique protein targets. Aminoacyl-tRNA synthetases (aaRSs), which have fundamental functions in translation, inhibit this process, stop protein synthesis and ultimately inhibit bacterial growth. The purpose of this study was to isolate piperolactam A compounds from the methanol extract of Piper betle leaves that have potential as antibacterials to inhibit the growth of Brucella sp. causing brucellosis in livestock and to analyse the mechanism of inhibitory activity of piperolactam A compounds against the aaRS enzyme through a molecular docking approach in silico. Piperolactam A was isolated from P. betle by column chromatography and characterized by UV, IR, 1D and 2D NMRs and MS, then tested for their inhibition mechanism against the enzymes threonyl-tRNA synthetase, leucyl-tRNA synthetase (LeuRS) and methionyl-tRNA synthetase in silico. The result in silico test is that piperolactam A has the potential to inhibit LeuRS enzyme with the greater binding affinity.

Bioinformatics analysis of candidate proteins Omp2b, P39 and BLS for Brucella multivalent epitope vaccines

This study focuses on analyzing the physicochemical properties, structural characteristics and dominant epitopes of Brucella outer membrane protein 2b (Omp2b), periplasmic binding protein (P39) and Brucella lumazine synthase (BLS) proteins by bioinformatics methods, and to provide a theoretical basis for constructing multi-epitope vaccines. The amino acid sequences of three kinds of proteins were obtained from the UniProt database. The highest frequency alleles in northern China were obtained from the AlleleFrequencies database. Analysis of the physicochemical properties of the proteins by ProtParam online software. Analysis of the secondary structure of the proteins were predicted by SOMPA online software. Using SWISS-MODEL online software constructed and analyzed the tertiary structure of the proteins. Using ABCpred, BepiPred, BCPred and SVMTrip online software analyzed linear B cell epitopes of proteins, The T cell dominant epitope of the protein was analyzed using SYFPEITHI, RANKPEP and IEDB online software. Omp2b was identified three linear B cell dominant epitopes, five CD8⁺ T cell dominant epitopes, and three CD4⁺ T cell dominant epitopes. P39 was identified three linear B cell dominant epitopes, two CD8⁺ T cell dominant epitopes, and two CD4⁺ T cell dominant epitopes. BLS was identified one linear B cell dominant epitope, one CD8⁺ T cell dominant epitope, and two CD4⁺ T cell dominant epitopes. The results indicated that epitope prediction of three Brucella vaccine candidate proteins can provide a theoretical basis for the construction of an ideal multivalent epitope vaccine against Brucella.

Comparison of the protective immunity elicited by a Brucella cocktail protein vaccine (rL7/L12+rTOmp31+rSOmp2b) in two different adjuvant formulations in BALB/c mice

In the present study, protective efficacy conferred by a cocktail protein consisted of Brucella L7/L12 ribosomal, truncated outer membrane protein 31 (TOmp31) and SOmp2b recombinant proteins in CpG ODN 1826+ Montanide ISA 70VG or Poly (I:C) adjuvants was evaluated and compared in BALB/c mice. Immunization of mice with both vaccine regimens elicited strong specific IgG responses (higher IgG2a titers over IgG1 titers), provided T helper1 (Th1) oriented immune responses and conferred protection levels compatible to the live vaccines against Brucella challenge. Vaccination of BALB/c mice with the cocktail protein in CpG ODN 1826+ Montanide ISA 70 V G adjuvants induced higher levels of antibody, IFN-γ/IL-2 and conferred more protection levels against B. melitenisis and B. abortus challenge than did the cocktail protein in Poly (I:C) formulation. In conclusion, both vaccine regimens are capable of stimulating specific Th1- biased immune responses and conferring cross protection against B. melitensis and B. abortus infections. Therefore, they could be introduced as new potential candidates for the development of subunit vaccines against Brucella infection.

In silico Design, and In vitro Expression of a Fusion Protein Encoding Brucella abortus L7/L12 and SOmp2b Antigens

Background:

L7/L12 is a protective antigen conserved in main Brucella pathogens and is considered as potential vaccine candidate. Outer membrane protein 2b is an immunogen conserved in all Brucella pathogens.

Materials and Methods:

The purpose of the current study was to in silico design a L7/L12-SOmp2b fusion protein and in vitro production of the chimera. Two possible fusion forms, L7/L12-SOmp2b and SOmp2b-L7/L12, were subjected to in silico modeling and analysis. Cloning and expression of the fusion protein has been done in the pET28a vector and Escherichia coli Bl21 (DE3), respectively.

Results:

Analysis and validation of the fusion proteins three-dimensional models showed that both models are in the range of native proteins. However, L7/L12-SOmp2b structure was more valid than the SOmp2b-L7/L12 model and subjected to in vitro production. The major histocompatibility complex II (MHC-II) epitope mapping using Immune Epitope DataBase indicated that the model contained good MHC-II binders. The L7/L12-Omp2b coding sequence was cloned in pET28a vector. The fusion was successfully expressed in E. coli BL21 by induction with isopropyl-β-d-thiogalactopyranoside. The rL7/L12-SOmp2b was purified with Ni-NTA column. The yield of the purified rL7/L12-SOmp2b was estimated by Bradford method to be 240 μg/ml of the culture. Western blot analysis revealed a specific reactivity with purified rL7/L12-SOmp2b produced in E. coli cells and showed the expression in the prokaryotic system.

Conclusions:

Our data indicates that L7/L12-SOmp2b fusion protein has a potential to induce both B- and T-cell-mediated immune responses and it can be evaluated as a new subunit vaccine candidate against brucellosis.

Histone Deacetylase 1 Plays an Acetylation-Independent Role in Influenza A Virus Replication

Influenza A viruses (IAVs) take advantage of the host acetylation system for their own benefit. Whether the nucleoprotein (NP) of IAVs undergoes acetylation and the interaction between the NP and the class I histone deacetylases (HDACs) were largely unknown. Here, we showed that the NP protein of IAV interacted with HDAC1, which downregulated the acetylation level of NP. Using mass spectrometry, we identified lysine 103 as an acetylation site of the NP. Compared with wild-type protein, two K103 NP mutants, K103A and K103R, enhanced replication efficiency of the recombinant viruses in vitro. We further demonstrated that HDAC1 facilitated viral replication via two paths: promoting the nuclear retention of NP and inhibiting TBK1-IRF3 pathway. Our results lead to a new mechanism for regulating NP acetylation, indicating that HDAC1 may be a possible target for antiviral drugs.

A review of Brucellosis in Iran: Epidemiology, Risk Factors, Diagnosis, Control, and Prevention

Brucellosis caused by species of Brucella is among the most prevalent zoonoses with the annual incidence of half a million cases globally. Most parts of Iran are endemic for brucellosis, and the annual incidence of the human and animal brucellosis is still high. At present, there is no safe and protective human vaccine against brucellosis, and the only preventive strategy is animal vaccination, which harbors significant disadvantages. Considering the identification of many immunogenic proteins in Brucella, several studies have recently been performed to evaluate the vaccine potency of such antigens as a new subunit vaccine candidate. This review represents an overview of brucellosis in Iran, including epidemiology, transmission routs, diagnosis, and treatment. Moreover, it mainly highlights the history of brucellosis control and prevention in Iran, including eradication programs, vast livestock vaccination programs, and subunit vaccine studies. It also discusses major problems that the country encounters with disease control. In recent years, Persian scientists have focused on evaluating the efficacy of best Brucella immunogens in vivo to introduce a new subunit vaccine. The results of some studies could demonstrate the vaccine potential of some immunogens.