Multi-epitope vaccine candidate design for dengue virus.

Dengue Fever (DF) is a vector-borne neglected viral disease with a high burden in the sub-tropics of Asia and Africa. Aedes aegypti is responsible for 90% of cases in the global burden of disease. The primary goal of the treatment is to eliminate the virus from the bloodstream of affected individuals. A successful dengue vaccine must elicit both neutralizing antibodies and cell-mediated immunity and there is no vaccine to date to prevent DF. A multi-epitope vaccine composed of a series of or overlapping peptides is, therefore, an ideal approach for the prevention and treatment of pathogenic organisms. An immunoinformatics approach was employed to design a theoretical multi-epitope vaccine candidate. This vaccine candidate consists of linear B-cell epitope, TH cells epitope and CTL of reported potential vaccine candidates. These epitopes were linked together with suitable linkers and adjuvant at the N terminal and C terminal. The 3D Structure of the vaccine was modeled, refined and validated using computational tools. Protein-protein docking of vaccine candidates with TLR3 protein results in efficient binding. Immune stimulation of vaccine candidates predicted high levels of IgG and IgM. This candidate vaccine should be validated experimentally using suitable in-vivo and in-vitro studies to use in dengue fever virus elimination programmes.

An ANN model for the differential diagnosis of tuberculosis and sarcoidosis.

Sarcoidosis is often misdiagnosed as tuberculosis and consequently mistreated owing to inherent limitations in histopathological and radiological presentations. It is known that the differential diagnosis of Tuberculosis and Sarcoidosis is often non-trivial and requires expertise and experience from clinicians. Therefore, it is of interest to describe a multilayer neural network model to differentiate pulmonary tuberculosis from Sarcoidosis using signal intensity data from blood transcriptional microarray. Genes that are significantly upregulated in Pulmonary Tuberculosis and Sarcoidosis in comparison with healthy controls were used in the model. The model classified Pulmonary Tuberculosis and Sarcoidosis with 95.8% accuracy. The model also helps to identify gene markers that are differentially upregulated in the two clinical conditions.

Virtual screening of a MDR-TB WhiB6 target identified by gene expression profiling.

Multidrug resistance in M. tb has become a huge global problem due to drug resistance. Hence, the treatment remains a challenge, even though short term chemotherapy is available. Therefore, it is of interest to identify novel drug targets in M.tb through gene expression profiling complimented by a subtractive proteome model. WhiB6 is a transcriptional regulator protein and a known drug resistant marker that is critical in the secretion dependent regulation of ESX-1, which is specialized for the deployment of host membrane-targeting proteins. The WhiB6 protein structure was modelled ab initio and was docked with a library of 173 phytochemicals with potential antituberculosis activity to the identified drug marker to find novel lead molecules. UDP-galactopyranose and GDP-L-galactose were identified to be potential lead molecules to inhibit the target WhiB6. The results were compared with the first line drugs for MDR-TB by docking with WhiB6. Data showed that Ethambutol showed better binding ability to WhiB6 but the afore mentioned top ranked phytochemicals were found to be better candidate molecules. The chosen candidate lead molecules should be further validated by suitable in vitro or in vivo investigation.

Protein interaction studies of curli fimbriae in Escherichia coli biofilms.

Catheter-associated urinary tract infections (CAUTIs) caused by biofilms on indwelling medical devices are the most common type of nosocomial infections, a major health concern due to complications and frequent recurrence. The infections are most often caused by Escherichia coli. Curli are proteinaceous components of a complex extracellular matrix produced by various strains of Enterobacteriaceae. Curli fibers are involved with adhesion to surfaces, cell aggregation and biofilm formation. Therefore, it is of interest to study the protein interactions in curli biogenesis, identifying proteins involved in curli biogenesis, the interactions and development of a combinatorial library of novel lead molecules against biofilm formation by Escherichia coli. Targeting the CsgG protein of Escherichia coli could provide new treatment modalities to fight CAUTIs, better. This study may also help study infections caused by various strains of Enterobacteriaceae, in general.

Molecular docking analysis of phytoconstituent from Momordica charantia with Guanylate Cyclase catalytic domain.

Soluble guanylate cyclase (sGC) is a type of lyase enzyme with profoundly increasing importance in treatments of cardiovascular and neurodegenerative disorders. Modulation of sGC activity demonstrated beneficial effects against Parkinson's disease by reducing glutamate excitotoxicity. It is of interest to evaluate the pharmacological activity of Momordica charantia phytoconstituent (DGalacturonic acid) and ODQ with catalytic domain of sGC enzyme, using Autodock version 4.2 programs. Docking results revealed the binding ability of ODQ at the allosteric sites of sGC. D-galacturonic acid also shows binding interaction at the same allosteric sites in the catalytic domain of sGC like ODQ. Results show that both the ligands have efficient binding to THR 474 amino acid residue of beta 1 subunit of the enzyme. The drug likeliness score further implies the suitability of D-Galacturonic acid as a drug-like molecule. The binding property of ODQ and D-Galacturonic acid with the catalytic domain help to inhibit sGC activity having pharmacological effects. Moreover, ODQ interaction with heme site of sGC is already known while its interaction with the catalytic domain is shown in this report.

Phytochemical derivatives targeting fliJ flagellar protein from Escherichia coli.

Approximately 50 per cent of nosocomial infections are caused by the use of indwelling medical devices. The surfaces of devices are ideal sites of attachment for bacterial cells and an increase in biofilm formation. Biofilms have been a constant concern due to their complex extracellular matrix (ECM) resulting in multiple drug resistance. E. coli is known to associate with biofilms. Therefore it is of interest to identify the proteins associated to biofilm formation in Escherichia coli through literature survey, investigate their protein-protein interactions and identify indispensible proteins of biofilm formation. These proteins were further analyzed and fliJ was identified as the target, based on betweenness, centrality and radiality. 87 phytochemicals were found to be associated with the microbe in question and were docked with the target using Molegro Virtual Docker (MVD) 5.0. The results showed that geranyl pyrophosphate, ferulic acid 4-o-b-d-glucuronide, 5-8'-dehydrodiferulic acid and geranyl diphosphate showed maximum activity. A combinatorial library of 96 models was generated using the four phytochemicals binding with fliJ.

Meta-analysis study to evaluate the association of MTHFR C677T polymorphism with risk of ischemic stroke.

Ischemic stroke is a condition characterized by reduced blood supply to part of the brain, initiating the ischemic cascade, leading to dysfunction of the brain tissue in that area. It is one of the leading causes of death and disability and is estimated to cause around 5.7 million deaths worldwide. Methyl tetra hydro-folate reductase (MTHFR) is a rate limiting enzyme in the methyl cycle which catalyzes the only biochemical reaction which produces 5, Methyl tetra hydro folate, the co-substrate for the re-methylation of homocystiene to produce methionine. MTFHR C677T is a common mutation of MTHFR and those homozygous for the MTFHR C677T produce a thermo-labile form of the protein with drastically reduced catalytic activity resulting in elevated plasma homocystiene levels - a common risk factor for cardiovascular diseases. However, the role of MTHFR C677T in ischemic stroke remains unclear. To evaluate this association, we carried out a meta-analysis of existing published studies, which included 72 studies involving 12390 cases and 16274 controls. The forest plot was made to evaluate the overall risk of the mutation in the etiology of Ischemic Stroke. The overall Odds- ratio of the study was found to be 1.319 for random effects model, revealing a ∼32% increased risk of Ischemic stroke in the presence of MTHFR C667T mutation compared to controls. Publication bias in the study was analyzed using funnel plot which revealed that only 7 studies out of the 72 contributed to publication bias. These 7 studies were excluded and Meta-analysis was repeated for 65 studies and overall odds-ratio was 1.306, which showed that there was a 30% higher risk of Ischemic stroke in the presence of MTHFR C667T.

Pheophytin a isolated from the seagrass Syringodium isoetifolium plausibly blocks umuC proteins of select bacterial pathogens, in silico.

AIMS: This investigation is designed to evaluate the antibacterial efficiency of the noodle grass Syringodium isoetifolium, which is commonly found in the Indian coastal waters. Also, this study characterizes the active compound and predicts the mode of action in silico. METHODS AND RESULTS: Human pathogenic bacteria were treated with crude metabolites of S. isoetifolium. The potent fraction b was analysed by UV/VIS, Spectroscopy RP-HPLC, FT-IR, ESI-Mass and 1 H and 13 C NMRs and determined to be a hydrate of pheophytin a (C55 H74 N4 O6 ). The isolated compound Pheo had MIC values of 6·2 ± 0·7 (Salmonella typhi) and 12·5 ± 0·8 (Escherichia coli and Pseudomonas aeruginosa) µg ml-1 . Molecular docking studies of the compound were done to find the binding sites on the pathogens using a Molegro Virtual Docker platform. Pheo targets umuC proteins by binding compactly to five amino acid residues with interaction energy of -3·66 and a Moldock score of -160·175. CONCLUSIONS: Hence, we conclude that pheophytin a, besides being an accessory photosynthetic pigment, also has proven to be antibacterial against human pathogens. Lesser MIC values with definite binding sites predicted in silico are suggestive of a precise of action for this compound. SIGNIFICANCE AND IMPACT OF THE STUDY: Easy extraction methods of the active compound that has a definite target render this under-explored seagrass a good source of antibacterial compound against human pathogenic bacteria. This learning may favour more researches in this unexplored area to build up Pheo-based natural products as antibiotic therapies.

Insights on the structural perturbations in human MTHFR Ala222Val mutant by protein modeling and molecular dynamics.

Methylenetetrahydrofolate reductase (MTHFR) protein catalyzes the only biochemical reaction which produces methyltetrahydrofolate, the active form of folic acid essential for several molecular functions. The Ala222Val polymorphism of human MTHFR encodes a thermolabile protein associated with increased risk of neural tube defects and cardiovascular disease. Experimental studies have shown that the mutation does not affect the kinetic properties of MTHFR, but inactivates the protein by increasing flavin adenine dinucleotide (FAD) loss. The lack of completely solved crystal structure of MTHFR is an impediment in understanding the structural perturbations caused by the Ala222Val mutation; computational modeling provides a suitable alternative. The three-dimensional structure of human MTHFR protein was obtained through homology modeling, by taking the MTHFR structures from Escherichia coli and Thermus thermophilus as templates. Subsequently, the modeled structure was docked with FAD using Glide, which revealed a very good binding affinity, authenticated by a Glide XP score of -10.3983 (kcal mol(-1)). The MTHFR was mutated by changing Alanine 222 to Valine. The wild-type MTHFR-FAD complex and the Ala222Val mutant MTHFR-FAD complex were subjected to molecular dynamics simulation over 50 ns period. The average difference in backbone root mean square deviation (RMSD) between wild and mutant variant was found to be ~.11 Å. The greater degree of fluctuations in the mutant protein translates to increased conformational stability as a result of mutation. The FAD-binding ability of the mutant MTHFR was also found to be significantly lowered as a result of decreased protein grip caused by increased conformational flexibility. The study provides insights into the Ala222Val mutation of human MTHFR that induces major conformational changes in the tertiary structure, causing a significant reduction in the FAD-binding affinity.

Relevance of systems biological approach in the differential diagnosis of invasive lobular carcinoma & invasive ductal carcinoma.

Breast cancer is a malignant neoplasm originating from breast tissue, most commonly from the inner lining of milk ducts or the lobules that supply the ducts with milk. ILCs and IDCs vary from each other with respect to various histological, biological and clinical features. Remarkably, ductal tumors tending to form glandular structures, whereas lobular tumors are less cohesive and tends to invade in single file. The high degree of similarity in the prognoses of IDC and ILC makes it beneficial to develop a differential diagnostic protocol to classify the two conditions. The main goal of the study is to construct the genetic regulatory network from the microarray data using biological knowledge and constraint-based inferences, in order to explore the potential significant gene regulatory networks that can differentiate IDC and ILC and thereby understand the complex interactions that are influenced by the genetic networks. Out of the 54676 genes present on the GPL570 platform- 29 genes exhibited 4 fold up regulation in case of IDC and 22 in the case of ILC. The ductal and lobular tumors displayed a striking difference in the expression of genes associated with cell adhesion, protein folding, and protein phosphorylation and invasion. Construction of separate gene regulation networks for IDC and ILC on the basis of gene expression altercation can be utilized in understanding the distinction in the possible mechanism that underlies the pathological differences between the two, which can be exploited in identifying diagnostic or therapeutic targets.