Identification and characterization of the cofactor-independent phosphoglycerate mutases of Dirofilaria immitis and its Wolbachia endosymbiont

Three novel immunogenic proteins determined through 2-Dimensional electrophoresis and mass spectrometry with immune serum confer protection against challenge with porcine Pasteurella multocida in mouse models

Pasteurella multocida is an important zoonotic pathogen that causes multiple diseases in both animals and humans. Test of good immunogenic proteins is beneficial for vaccine development and disease control. In the present study, we determined four novel immunogenic proteins of P. multocida by using 2-DE MALDI-TOF MS with immune serum. These four proteins included a trimethylamine-N-oxide reductase TorA, a translation elongation factor Ts, a phosphoglyceromutase PGAM, and a peroxiredoxin PrX. Among these proteins, TorA, Prx, and PGAM were successfully expressed by using E. coli. Western-blotting assays showed that recombinant TorA, Prx, and/or PGAM displayed good reactions with infectious sera of P. multocida serogroups A, B, D and F. Immunization of either rTorA, rPrx, and/or rPGAM induced significantly high levels of antibodies as well as IFN-γ, IL-4 and IL-10 in mice (P < 0.01). Protective efficacy tests revealed that vaccination of either rTorA, rPrx, and/or rPGAM protected 60% ~ 80% of the tested mice against the challenge with P. multocida field isolate. Our results obtained from the present study suggest that these three proteins could be tested as good vaccine candidates against P. multocida infections.

The Wolbachia Symbiont: Here, There and Everywhere

Wolbachia symbionts, first observed in the 1920s, are now known to be present in about 30-70% of tested arthropod species, in about half of tested filarial nematodes (including the majority of human filarial nematodes), and some plant-parasitic nematodes. In arthropods, they are generally viewed as parasites while in nematodes they appear to be mutualists although this demarcation is not absolute. Their presence in arthropods generally leads to reproductive anomalies, while in nematodes, they are generally required for worm development and reproduction. In mosquitos, Wolbachia inhibit RNA viral infections, leading to populational reductions in human RNA virus pathogens, whereas in filarial nematodes, their requirement for worm fertility and survival has been channeled into their use as drug targets for filariasis control. While much more research on these ubiquitous symbionts is needed, they are viewed as playing significant roles in biological processes, ranging from arthropod speciation to human health.

Analysis of the regulatory mechanism of deoxynivalenol production using omics

Fusarium species are plant pathogens that produce various mycotoxins. Here, the regulatory mechanism of deoxynivalenol production in Fusarium asiaticum was analyzed using proteomic, metabolomic and transcriptomic methods. F. asiaticum was induced to produce deoxynivalenol by adding agmatine to the culture medium. Subsequently, metabolites of the glycolysis system were increased but mRNAs of the corresponding proteins were not up regulated. We speculated that this phenomenon was due to the up regulation of the 6-fructokinase and pyruvate kinase proteins, which are key enzymes of glycolysis. We discuss the relationship of metabolism with the regulation of deoxynivalenol production in F. asiaticum.

Functional attributes of evolutionary conserved Arg45 of Wolbachia (Brugia malayi) translation initiation factor-1

AIM

Wolbachia is a promising antifilarial chemotherapeutic target. Translation initiation factor-1 (Tl IF-1) is an essential factor in prokaryotes. Functional characterization of Wolbachia's novel proteins/enzymes is necessary for the development of adulticidal drugs.

MATERIALS & METHODS

Mutant, Wol Tl IF-1 R45D was constructed by site directed mutagenesis. Fluorimetry and size exclusion chromatography were used to determine the biophysical characteristics. Mobility shift assay and fluorescence resonance energy transfer were used to investigate the functional aspect of Wol Tl IF-1 with its mutant.

RESULTS

Both wild and mutant were in monomeric native conformations. Wild exhibits nonspecific binding with ssRNA/ssDNA fragments under electrostatic conditions and showed annealing and displacement of RNA strands in comparison to mutant.

CONCLUSION

Point mutation impaired RNA chaperone activity of the mutant and its interaction with nucleotides.

Molecular modeling, dynamics, and an insight into the structural inhibition of cofactor independent phosphoglycerate mutase isoform 1 from Wuchereria bancrofti using cheminformatics and mutational studies

Phosphoglycerate mutase catalyzes the interconversion between 2-phosphoglycerate and 3-phosphoglycerate in the glycolytic and gluconeogenic pathways. They exist in two unrelated forms, that is either cofactor (2,3-diphosphoglycerate) dependent or cofactor-independent. These two enzymes have no similarity in amino acid sequence, tertiary structure, and in catalytic mechanism. Wuchereria bancrofti (WB) contains the cofactor-independent form, whereas other organisms can possess the dependent form or both. Since, independent phosphoglycerate mutase (iPGM) is an essential gene for the survival of nematodes, and it has no sequence or structural similarity to the cofactor-dependent phosphoglycerate mutase found in mammals, it represents an attractive drug target for the filarial nematodes. In this current study, a putative cofactor-iPGM gene was identified in the protein sequence of the WB. In the absence of crystal structure, a three-dimensional structure was determined using the homology modeling approximation, and the most stable protein conformation was identified through the molecular dynamics simulation studies, using GROMACS 4.5. Further, the functional or characteristic residues were identified through the sequence analysis, potential inhibitors were short-listed and validated, and potential inhibitors were ranked using the cheminformatics and molecular dynamics simulations studies, Prime MM-GBSA approach, respectively.

Characterization of cofactor-independent phosphoglycerate mutase isoform-1 (Wb-iPGM) gene: a drug and diagnostic target from human lymphatic filarial parasite, Wuchereria bancrofti

The inter-conversion of 3-phosphoglycerate and 2-phosphoglycerate during glycolysis and gluconeogenesis in filarial nematodes, is catalyzed by a co-factor-independent phosphoglycerate mutase (iPGM). The gene encoding iPGM isoform-1 was amplified from Wuchereria bancrofti, the major causative agent of human lymphatic filariasis. Partial genomic DNA (gDNA) fragment of the gene was also amplified from periodic and sub-periodic forms of W. bancrofti and Brugia malayi and sequenced. The Wb-iPGM isoform-1 gene encodes an ORF of 515 amino acids and is found to share 99.4%, 96.0%, and 64.0% amino acid sequence identity with iPGM of B. malayi, Onchocerca volvulus, and Caenorhabditis elegans, respectively. Serine and all the other 13 amino acid residues involved in the catalytic function of iPGM are highly conserved. Further comparison of iPGM nucleotide and amino acid sequences of Wolbachia of B. malayi with Wb-iPGM showed 41% and 54.4% similarity, respectively. The analysis of partial genomic and amino acid sequences and phylogenetic tree of Wb-iPGM indicated that this gene, apart from being a potential drug target, could provide diagnostic, taxonomical, and evolutionary markers. This is the first report of the characterization of iPGM gene from W. bancrofti.

Characterization of type II and III restriction-modification systems from Bacillus cereus strains ATCC 10987 and ATCC 14579

The genomes of two Bacillus cereus strains (ATCC 10987 and ATCC 14579) have been sequenced. Here, we report the specificities of type II/III restriction (R) and modification (M) enzymes. Found in the ATCC 10987 strain, BceSI is a restriction endonuclease (REase) with the recognition and cut site CGAAG 24-25/27-28. BceSII is an isoschizomer of AvaII (G/GWCC). BceSIII cleaves at ACGGC 12/14. The BceSIII C terminus resembles the catalytic domains of AlwI, MlyI, and Nt.BstNBI. BceSIV is composed of two subunits and cleaves on both sides of GCWGC. BceSIV activity is strongly stimulated by the addition of cofactor ATP or GTP. The large subunit (R1) of BceSIV contains conserved motifs of NTPases and DNA helicases. The R1 subunit has no endonuclease activity by itself; it strongly stimulates REase activity when in complex with the R2 subunit. BceSIV was demonstrated to hydrolyze GTP and ATP in vitro. BceSIV is similar to CglI (GCSGC), and homologs of R1 are found in 11 sequenced bacterial genomes, where they are paired with specificity subunits. In addition, homologs of the BceSIV R1-R2 fusion are found in many sequenced microbial genomes. An orphan methylase, M.BceSV, was found to modify GCNGC, GGCC, CCGG, GGNNCC, and GCGC sites. A ParB-methylase fusion protein appears to nick DNA nonspecifically. The ATCC 14579 genome encodes an active enzyme Bce14579I (GCWGC). BceSIV and Bce14579I belong to the phospholipase D (PLD) family of endonucleases that are widely distributed among Bacteria and Archaea. A survey of type II and III restriction-modification (R-M) system genes is presented from sequenced B. cereus, Bacillus anthracis, and Bacillus thuringiensis strains.