Tetrazoles as anticancer agents: A review on synthetic strategies, mechanism of action and SAR studies

Cancer is a leading cause of death worldwide. Even after the availability of numerous drugs and treatments in the market, scientists and researchers are focusing on new therapies because of their resistance and toxicity issues. The newly synthesized drug candidates are able to demonstrate in vitro activity but are unable to reach clinical trials due to their rapid metabolism and low bioavailability. Therefore there is an imperative requisite to expand novel anticancer negotiators with tremendous activity as well as in vivo efficacy. Tetrazole is a promising pharmacophore which is metabolically more stable and acts as a bioisosteric analogue for many functional groups. Tetrazole fragment is often castoff with other pharmacophores in the expansion of novel anticancer drugs. This is the first systematic review that emphasizes on contemporary strategies used for the inclusion of tetrazole moiety, mechanistic targets along with comprehensive structural activity relationship studies to provide perspective into the rational design of high-efficiency tetrazole-based anticancer drug candidates.

Gene expression microarrays: a 21st century tool for directed vaccine design

DNA microarray technology is a new and powerful tool that allows the simultaneous analysis of a large number of nucleic acid hybridization experiments in a rapid and efficient fashion. The development of the DNA microarray chip has been driven by modern techniques of microelectronic fabrication, miniaturization and integration to produce what is referred to as "laboratory-on-chip" devices. The application of DNA chip technology includes the comprehensive analysis of multiple gene mutations and expressed sequences with regard to newer drug designs, host-pathogen interactions and the design of new vaccines. An advantage of microarray technology is that it can assist researchers to better define and understand the expression profile of a given genotype associated with disease, adverse effects from exposure to certain stimuli, or the ability to understand or predict immune responses to specific antigens. This paper briefly reviews DNA microarray technology and its implications with special reference to vaccine design. The technical aspects comprising array manufacturing and design, array hybridization, formatting, scanning and data handling are also briefly discussed.

RUFY3 links Arl8b and JIP4-Dynein complex to regulate lysosome size and positioning

The bidirectional movement of lysosomes on microtubule tracks regulates their whole-cell spatial arrangement. Arl8b, a small GTP-binding (G) protein, promotes lysosome anterograde trafficking mediated by kinesin-1. Herein, we report an Arl8b effector, RUFY3, which regulates the retrograde transport of lysosomes. We show that RUFY3 interacts with the JIP4-dynein-dynactin complex and facilitates Arl8b association with the retrograde motor complex. Accordingly, RUFY3 knockdown disrupts the positioning of Arl8b-positive endosomes and reduces Arl8b colocalization with Rab7-marked late endosomal compartments. Moreover, we find that RUFY3 regulates nutrient-dependent lysosome distribution, although autophagosome-lysosome fusion and autophagic cargo degradation are not impaired upon RUFY3 depletion. Interestingly, lysosome size is significantly reduced in RUFY3 depleted cells, which could be rescued by inhibition of the lysosome reformation regulatory factor PIKFYVE. These findings suggest a model in which the perinuclear cloud arrangement of lysosomes regulates both the positioning and size of these proteolytic compartments.

Associations between cytokine/cytokine receptor single nucleotide polymorphisms and humoral immunity to measles, mumps and rubella in a Somali population

We genotyped a Somali population (n = 85; age < or =30 years) for 617 cytokine and cytokine receptor single nucleotide polymorphisms (SNPs) using Illumina GoldenGate genotyping to determine associations with measles, mumps and rubella immunity. Overall, 61 significant associations (P < or = 0.01) were found between SNPs belonging to cytokine receptor genes regulating T helper (Th)1 (IL12RB2, IL2RA and B) and Th2 (IL4R and IL10RB) immunity, and cytokine (IL1B, TNFA, IL6 and IFNB1) and cytokine receptor (IL1RA, IFNAR2, IL18R1, TNFRSF1A and B) genes regulating innate immunity and variations in antibody levels to measles, mumps and/or rubella. SNPs within two major inflammatory cytokine genes, TNFA and interleukin (IL) 6, showed associations with measles-specific antibodies. Specifically, the minor allele variant of rs1799964 (TNFA -1211 C>T) was associated with primarily seronegative values (median enzyme immunoassay index values < or =0.87; P = 0.002; q = 0.23) in response to measles disease and/or vaccination. A heterozygous variant CT for rs2069849 (IL6 +4272C>T; Phe201Phe) was also associated with seronegative values and a lower median level of antibody response to measles disease and/or vaccination (P = 0.004; q = 0.36) or measles vaccination alone (P = 0.008). Several SNPs within the coding and regulatory regions of cytokine and cytokine receptor genes showed associations with mumps and rubella antibody levels but were less informative as strong linkage disequilibrium patterns and lower frequencies for minor alleles were observed among these SNPs. Our study identifies specific SNPs in innate immune response genes that may play a role in modulating antibody responses to measles vaccination and/or infection in Somali subjects.

Clinical and environmental isolates of Burkholderia cepacia exhibit differential cytotoxicity towards macrophages and mast cells

Burkholderia cepacia is an emerging opportunistic pathogen that causes fatal infections in patients suffering from cystic fibrosis (CF) and chronic granulomatous disease. Various environmental isolates of B. cepacia are, however, capable of degrading environmental pollutants, such as trichloroethylene, 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), etc., and are also highly effective in controlling plant diseases caused by nematodes and fungi. Such strains have therefore been proposed for environmental release to clean up toxic dump sites or as biopesticides. Various efforts to distinguish between clinical and environmental isolates of B. cepacia with regard to their virulence characteristics have produced ambiguous results, suggesting that newer methods are needed to test for the presence or absence of pathogenic potential in B. cepacia strains proposed for environmental release. We now report that several clinical strains of B. cepacia secrete cytotoxic factors that allow macrophage and mast cell death in the presence of external ATP. Several environmental strains had reduced activity in this regard. We also demonstrate that, while all the strains secrete enzymes that have nucleoside diphosphate kinase (Ndk), adenylate kinase (Ak) and 5'-nucleotidase activity, the level of secretion of the 5'-nucleotidase (and/or ATPase/phosphatase) appears to be lower in the environmental strains than in the clinical strains. The secretion of these enzymes is specifically activated in the presence of eukaryotic proteins such as alpha2-macroglobulin. As macrophage-or mast cell surface-associated P2Z receptors promote their cell death in the presence of mM concentrations of ATP, and as the secreted ATP-using enzymes generate various phosphorylated or non-phosphorylated adenine nucleotides that may even be better agonists than ATP in activating the P2Z receptors or may act through the activation of additional purinergic receptors, such enzymes may play an important role in allowing B. cepacia to evade host defence.

Phagocytic cell killing mediated by secreted cytotoxic factors of Vibrio cholerae

Vibrio cholerae strain VB1 secretes a number of enzymes into the outside medium that utilize ATP as a substrate. Such enzymes are found in the outside medium during the mid-log phase of growth, when the optical density at 650 nm is about 0.4, and they demonstrate nucleoside diphosphate kinase (Ndk), 5' nucleotidase, and adenylate kinase (Ak) activities. We report that the filtered growth medium of V. cholerae, as well as the flowthrough fraction of a green Sepharose column during fractionation of the growth medium, had very little cytotoxicity by itself towards macrophages and mast cells but exhibited significant cytotoxicity in the presence of exogenous ATP. Such fractions, harboring 5' nucleotidase, Ndk, and presumably other ATP-utilizing enzymes, demonstrated enhanced macrophage and mast cell death; periodate-oxidized-ATP (oATP)-treated macrophage and mast cells or such cells exposed to 0.1 mM Mg(2+), where surface-associated P2Z receptors could not be activated, were not susceptible to subsequent ATP addition. Microscopic visualization of mast cells clearly demonstrated cell morphological changes such as swelling, vacuolization, and nuclear fragmentation following treatment with ATP and the growth medium of V. cholerae; however, these effects were suppressed if the mast cells were pretreated with oATP. These results strongly imply that the secreted ATP-utilizing enzymes of V. cholerae modulate the external ATP levels of the macrophage and mast cells, leading to their accelerated death, presumably through activation of P2Z receptors. Thus, development of inhibitors for such enzymes may reduce the level of V. cholerae infection; alternatively, mutations in such genes may eliminate V. cholerae survival in the gut and contribute to a safer live vaccine.

Induction of CD4 T cell proliferation and in vitro Th1-like cytokine responses to measles virus

Mechanisms that lead to induction of life-long immunity to measles virus (MV) are poorly understood. In the present study, we have assessed the activation, proliferation and cytokine secreting function of peripheral blood T cells from MV immune individuals. Expression of cell blastogenesis markers, such as increased forward light scatter and CD38 expression, peaked 5-7 days after infection of peripheral blood mononuclear cells (PBMC) with the live attenuated Edmonston strain of MV. Subset analysis revealed that both CD3- and CD3+ cells expressed activation markers but that the CD3+ T cells predominated late in the culture period corresponding to maximal proliferation and cell recovery. The majority of CD3+ T cells consisted of CD4+CD8- cells. IFN-gamma and IL-4 production similarly showed optimal production late in culture. Depletion of CD4 cells prior to culture and MV stimulation completely abrogated both IFN-gamma and IL-4 production, whereas depletion of CD8 cells did not diminish production, suggesting that CD4+CD8- T cells were principally involved in production of these cytokines. Finally, optimal IFN-gamma production was elicited at high MV doses and IL-4 at much lower doses. These results suggest that among MV immune individuals, in vitro responses to measles are dominated by CD4+ T cells that, depending on antigen dose, primarily produce a Th1-like and, to a lesser extent, a Th1/Th2-mixed pattern of cytokine release.

Engagement of phytoestrogens in breast cancer suppression: Structural classification and mechanistic approach

Cancer is the world's devastating disease, and breast cancer is the most common reason for the death of women worldwide. Many synthetic drugs and medications are provided with their beneficial actions, but all of these have side effects and resistance problems. Natural remedies are coming forward to overcome the disadvantages of synthetic drugs. Among the natural categories, phytoestrogens having a structural similarity of mammalian oestradiol proves its benefit with various mechanisms not only in the treatment of breast cancer but even to prevent the occurrence of postmenopausal symptoms. Phytoestrogens are plant-derived compounds that were utilized in ancient medications and traditional knowledge for its sex hormone properties. Phytoestrogens exert pleiotropic effects on cellular signalling and show effects on estrogen-dependent diseases. However, because of activation/inhibition of steroid hormonal receptor ER-α or ER-β, these compounds induce or inhibit steroid hormonal (estrogen) action and, therefore, have the potential to disrupt hormone (estrogen) signalling pathway. In this review, we have discussed and summarize the effect of certain phytoestrogens and their possible mechanisms that can substantiate advantageous benefits for the treatment of post-menopausal symptoms as well as for breast cancer.

Inter-operator variation in ELISPOT analysis of measles virus-specific IFN-gamma-secreting T cells

The ELISPOT assay is a highly sensitive technique used for the detection of individual cytokine releasing cells. We have developed an IFN-gamma ELISPOT assay utilizing unfractionated frozen peripheral blood mononuclear cells (PBMC) to quantify the frequency of measles virus (MV)-specific IFN-gamma-secreting T cells in 117 healthy children who had been previously immunized with two doses of the measles-mumps-rubella vaccine. We have also estimated the variability associated with the quantification of ELISPOT plates and compared the number of MV-specific IFN-gamma-secreting T cells for each subject as determined by two different operators of an ELISPOT reader. The median frequency of MV-specific IFN-gamma-producing memory T cells detected by this assay was 0.005 % and 0.01 % as determined by an in-house and commercial operator, respectively. Although we found a significant correlation (r = 0.83, p<0.0001) between the number of spots counted by the commercial and in-house operators of an ELISPOT reader, the median number of spots counted by the commercial operator was twice the number of spots counted by an in-house operator (p<0.001). This demonstrates the importance of using a common ELISPOT reader and operator, among other parameters, to quantify the number of spots when a large volume of plates are being scanned and analyzed.

Correlations among measles virus-specific antibody, lymphoproliferation and Th1/Th2 cytokine responses following measles-mumps-rubella-II (MMR-II) vaccination

Immunity to measles is conferred by the interplay of humoral and cellular immune responses, the latter being critical in maintaining long-term recall response. Therefore, it is important to evaluate measles-specific humoral and cellular immunity in populations several years after vaccination and understand the correlations among these measures of immunity. We examined measles-specific antibodies, lymphoproliferation and the Th1/Th2 signature cytokines, interferon (IFN)-gamma and interleukin (IL)-4, in a population-based cohort of healthy children from Olmsted County, Minnesota after two doses of measles-mumps-rubella-II (MMR-II) vaccine. We detected positive measures of measles-specific cellular and humoral immunity in the majority of our study population. However, a small proportion of subjects demonstrated an immune response skewed towards the Th2 type, characterized by the presence of either IL-4 and/or measles-specific antibodies and a lack of IFN-gamma production. Further, we observed a significant positive correlation between lymphoproliferation and secretion of IFN-gamma (r = 0.20, P = 0.0002) and IL-4 (r = 0.15, P = 0.005). Measles antibody levels were correlated with lymphoproliferation (r = 0.12, P = 0.03), but lacked correlation to either cytokine type. In conclusion, we demonstrated the presence of both long-term cellular and humoral responses after MMR-II vaccination in a significant proportion of study subjects. Further, a positive correlation between lymphoproliferation and IL-4 and IFN-gamma suggests that immunity to measles may be maintained by both Th1 and Th2 cells. We speculate that the Th2 biased response observed in a subset of our subjects may be insufficient to provide long-term immunity against measles. Further examination of the determinants of Th1 versus Th2 skewing of the immune response and long-term follow-up is needed.

A drift on liposomes to proliposomes: recent advances and promising approaches

Liposomes are nano-structured vesicles, made up of phospholipids that provide active ingredients at the site of action at a predetermined rate and add the advantage of the sustained-release formulation. Liposomes have stability issues that tend to agglomerate and fuse upon storage, which reflects their drawback. Hence to overcome the aggregation, fusion, hydrolysis, and/or oxidation problems associated with liposomes a new technology named Proliposomes has been introduced. Proliposomes are defined as carbohydrate carriers coated with phospholipids, which upon addition of water generate liposomes. The objective of the review is to cover the concept of proliposomes for pulmonary or alveolar delivery of drugs and compare it with that of liposomes; highlight the methods used for preparations along with the characterization parameters. This is the first systematic review that covers the categorization of liposomes, characteristic methods, and recent examples of drugs from 2015 to 2021, supplied in form of proliposomes to the macrophages as well as others and offers an advantage over the free drug by offering a prolonged drug release and sufficient bioavailability in addition to overcome the stability issues related to liposomes. Since this is a very new technology and many scientists are continuously working in this field to make the drug available for clinical trials and ultimately in the market for the targeted delivery of drugs with better storage life.HIGHLIGHTSProliposomes as an alternative to overwhelm the stability and storage-related issues of liposomes.Anhydrous carbohydrate carriers are utilized for proliposomal preparation.Inhaled delivery of drugs as solid lipid nanoparticles offers a significant impact on pulmonary tract infections, particularly in cystic fibrosis.Size of liposomes attained after proliposome hydrolysis is critical for drug delivery via respiration.

Immunoprophylactic properties of 71-kDa cell wall-associated protein antigen of Mycobacterium tuberculosis H37Ra

Proteins associated with the cell wall peptidoglycan (CW-Pr) of Mycobacterium tuberculosis H37Ra were isolated to evaluate their immunoreactivity and immunoprophylactic properties against experimental tuberculosis. Chemical treatment of the cell wall with trifluoromethanesulfonic acid: anisole (2:1) resulted in the release of three proteins of 71, 60 and 45 kDa as resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A comparative study of immune responses elicited to individual proteins in mice immunized with CW-Pr emulsified in incomplete Freund's adjuvant showed the 71-kDa protein to be the most immunoreactive antigen. This 71-kDa protein was found to cross-react with the 70-kDa heat shock protein from M. leprae and possessed ATPase activity. Mice immunized with the 71-kDa protein exhibited significantly higher immune responses, on the basis of T and B cell reactivity, as compared to a M. bovis Bacillus Calmette Guerin (BCG)-vaccinated group. The culture supernatants collected from 71-kDa stimulated lymphocytes stimulated exhibited increased interferon-gamma and interleukin-2 production. The protective efficacy of the 71-kDa protein in comparison to BCG was determined by challenging the mice with a virulent strain M. tuberculosis H37Rv. The 71-kDa protein was found to be more protective in animals challenged at 8 and 16 weeks post immunization, shown by increased survival rates and decreased viable bacilli counts in the target organs as compared to BCG-vaccinated animals.

Protective efficacy of mycobacterial 71-kDa cell wall associated protein using poly (DL-lactide-co-glycolide) microparticles as carrier vehicles

Microparticles composed of poly (DL-lactide-co-glycolide) (DL-PLG) were used as delivery vehicles for evaluating the immunoreactive and immunoprotective properties of 71-kDa cell wall associated protein of Mycobacterium tuberculosis H37Ra. Mice immunized with 71-kDa microparticles entrapped in DL-PLG (PLG-MPs) exhibited significantly higher T-cell stimulation and cytokine release in comparison to 71-kDa emulsified in Freund's incomplete adjuvant (FIA) as well as a BCG vaccinated group throughout the post-immunization (p.im.) period. Further, the protective efficacy of 71-kDa was evaluated on the basis of survival rates and viable bacilli load in different organs at 30 days post challenge (p.c.), with the median lethal dose (LD50) of M. tuberculosis H37Rv at weeks 8 and 16 p.im. Both 71-kDa-PLG and 71-kDa-FIA immunized groups exhibited a comparable protection (90%) which was significantly higher (P < 0.5) than in the BCG group (70%) at week 8 p.im. and it was consistent with the decreased bacterial load in the target organs. However, on increasing the interval of challenge to 16 weeks p.im., the protective efficacy of 71-kDa-PLG was sustained (85%) while that of 71-kDa-FIA began to wane (70%). Further. the 71-kDa-PLG immunized group exhibited a significantly higher (P < 0.001) clearance of bacterial load from the lungs and livers in comparison to the 71-kDa-FIA immunized group. The results suggest the long-term protective potential of a PLG-microparticle based antigen delivery system for tuberculosis.

Lack of association between transporter associated with antigen processing (TAP) and HLA-DM gene polymorphisms and antibody levels following measles vaccination

The transporter associated with antigen processing (TAP) and human leukocyte antigen-DM (HLA-DM) genes are involved in the antigen-processing pathway of both HLA class I and class II-restricted antigen presentation. We hypothesized that polymorphisms within the TAP and DM genes may influence antibody levels following measles vaccination. We examined TAP and DM polymorphisms in 242 school children from Olmsted County, Minnesota, USA who received one dose of measles-mumps-rubella-II (MMR-II) vaccine at the age of 15 months. Based on the level of serum measles-specific immunoglobulin G (IgG) antibodies, subjects were classified as seronegatives (n = 72) or seropositives (n = 170). We determined TAP1 and TAP2 allele types by polymerase chain reaction (PCR) amplification of specific alleles (PASA) and determined DM allele type by PCR amplification followed by direct sequencing of the polymorphic sites. We analysed the data for any TAP or DM allelic association with antibody levels post measles vaccination using the chi-square test and univariate linear regression analysis. We found no trend in the overall distribution of TAP and DM genotype frequencies between seronegative and seropositive subjects, suggesting that TAP and DM polymorphism and antibody levels following measles vaccination are not directly associated. In addition, we did not find an association between TAP (TAP1, P = 0.71; TAP2, P = 0.87) or DM (DMA, P = 0.42; DMB, P = 0.71) homozygosity and seronegativity to measles vaccine in this study group. Our study suggests that TAP and DM gene polymorphisms do not influence antibody levels post measles vaccination.

Binary adsorption of [Pb(II) + Co(II)] from aqueous solution using thiolated saw dust

Technology advancement has contributed to an increase in industrial activities, resulting in the introduction of metal ions into water resources at concentrations well above the WHO limits. Heavy metals are highly toxic and carcinogenic; they usually occur as multicomponent mixtures in the aquatic environment. In the present study, batch experiments have been conducted to study the dependence of varying concentration, time, pH and temperature on the uptake of Pb(II) as a pure component under equilibrium conditions using thiolated saw dust. Saw dust has been chemically modified with thioglycolic acid and characterised using proximate and FTIR analyses, the degree of thiolation has also been determined. To determine the effect of the presence of Co(II) ions on the uptake of Pb(II) ions, batch experiments for [Pb(II) + Co(II)] mixture have been carried out for concentration ratios of 1:0, 1:1, 1:2, 1:3, 1:4 of Pb:Co at pH 5 and data has been interpreted using Langmuir competitive isotherm, which shows that adsorption of Pb(II) has been suppressed by the presence of Co(II) ions in the binary solution, hence the adsorption process is antagonistic in nature. The study also indicates the possibility of simultaneous removal of both metal ions using low cost bioadsorbent, which is economical especially for application in small-scale industries.

Cellular immune responses to cell wall peptidoglycan associated protein antigens in tuberculosis patients and healthy subjects

We have isolated cell wall peptidoglycan associated proteins (CW-Pr) of Mycobacterium tuberculosis H37Ra by chemical treatment with trifluoromethanesulfonic acid:anisole (2:1), which further resolved into 71, 60 and 45 kDa proteins on SDS-PAGE. A study was carried out to investigate the immunoreactivity of these proteins with blood samples from 4 categories, including 15 tuberculous patients (TB), 5 tuberculous patients on ATT (TBT), 10 PPD non-reactive healthy controls (HPPD-) and 11 PPD reactive healthy controls (HPPD+). Comparing the proliferative responses to cell wall protein antigens, it was observed that the 71 kDa protein gave maximum stimulation with PBMCs from the TB and HPPD+ groups. The adherent PBMCs from the TB group also demonstrated enhanced phagocytosis, particularly in the presence of 71 and 45 kDa proteins, and the phagocytic index was significantly higher (P < 0.05) than the TBT group. However, PBMCs from of the groups recognized the 60 kDa cell wall antigen. Our results suggest that the 71 kDa protein from the cell wall of M. tuberculosis is highly immunogenic.

Immunoreactivity of peptides generated by limited proteolysis of 71-kDa cell wall protein of Mycobacterium tuberculosis H37Ra using PLG-microparticles

Peptide mapping by limited proteolysis of a highly protective 71-kDa cell wall-associated protein of Mycobacterium tuberculosis H37Ra was carried out in order to identify key protective determinants within the native protein. The 71-kDa protein, which had an isoelectric point of 4.25, was digested into eight major bands at 48 h using trypsin and pepsin at equal enzyme to protein ratios (pH 5.5). The in vitro lymphocyte reactivity of individual peptides suggested P1, P2 and P5 to be significantly immunoreactive in mice immunized with native 71-kDa-polylactide-coglyeolide (PLG); however, the reactivity was significantly lower than that of the native 71-kDa protein. Immunization of mice with a pooled fraction (upper fraction-71 kDa) of more immunoreactive peptides (consisting of P1 and P2) did not further boost their immunoreactivity. However, P1 and P2 exhibited comparable or even higher lymphocyte proliferation in human tuberculous and control subjects. These data suggest distinct antigenic specificities in humans and mice and further substantiate the use of the 71-kDa protein or its peptides P1 and P2 as potential vaccine candidates for tuberculosis.

Ferromagnetism in Defected TMD (MoX2, X = S, Se) Monolayer and Its Sustainability under O2, O3, and H2O Gas Exposure: DFT Study

Spin-polarized density-functional theory (DFT) has been employed to study the effects of atmospheric gases on the electronic and magnetic properties of a defective transition-metal dichalcogenide (TMD) monolayer, MoX₂ with X = S or Se. This study focuses on three single vacancies: (i) molybdenum "V_Mo"; (ii) chalcogenide "V_X"; and (iii) di-chalcogenide "V_X2". Five different samples of sizes ranging from 4 × 4 to 8 × 8 primitive cells (PCs) were considered in order to assess the effect of vacancy-vacancy interaction. The results showed that all defected samples were paramagnetic semiconductors, except in the case of V_Mo in MoSe₂, which yielded a magnetic moment of 3.99 μ_B that was independent of the sample size. Moreover, the samples of MoSe₂ with V_Mo and sizes of 4 × 4 and 5 × 5 PCs exhibited half-metallicity, where the spin-up state becomes conductive and is predominantly composed of dxy and dz2 orbital mixing attributed to Mo atoms located in the neighborhood of V_Mo. The requirement for the establishment of half-metallicity is confirmed to be the provision of ferromagnetic-coupling (FMC) interactions between localized magnetic moments (such as V_Mo). The critical distance for the existence of FMC is estimated to be dc≅ 16 Å, which allows small sample sizes in MoSe₂ to exhibit half-metallicity while the FMC represents the ground state. The adsorption of atmospheric gases (H₂O, O₂, O₃) can drastically change the electronic and magnetic properties, for instance, it can demolish the half-metallicity characteristics. Hence, the maintenance of half-metallicity requires keeping the samples isolated from the atmosphere. We benchmarked our theoretical results with the available data in the literature throughout our study. The conditions that govern the appearance/disappearance of half-metallicity are of great relevance for spintronic device applications.

Mycobacterial proteins--immune targets for antituberculous subunit vaccine

Cellular and humoral immunity induced by Mycobacterium tuberculosis has led to identification of newer vaccine candidates, but despite this, many questions concerning the protection against tuberculosis remain unanswered. Recent progress in this field has centered on T cell subset responses and cytokines that these cells secrete. There has been a steady progress in identification and characterization of several classes of major mycobacterial proteins which includes secretory/export proteins, cell wall associated proteins, heat shock proteins and cytoplasmic proteins. The protein antigens are now believed to represent the key protective immunity inducing antigens in the bacillus. In this review, various mycobacterial protein antigens of vaccination potential are compared for their efficacy in light of current immunological knowledge.

Zebrafish as a model organism to study sporadic Alzheimer's disease: Behavioural, biochemical and histological validation

Alzheimer's disease (AD) is a global burden to the healthcare system with no viable treatment options till date. Rodents and primates have been extensively used as models for understanding AD pathogenesis and identifying therapeutic targets. However, the focus is now shifting towards developing alternate models. Zebrafish is emerging as a preferred model for neurodegenerative conditions because of its simple nervous system, highly conserved genome and short duration required to model disease condition. The present study is aimed to develop streptozotocin (STZ)-induced model of sporadic AD (sAD) in zebrafish. STZ was administered to adult zebrafish (4-6 mo) at different doses (1 to 50 mg/kg body weight, intracerebroventricularly). Kaplan-Meier survival analysis revealed time and dose dependent mortality in the zebrafish administered with STZ. Based on survival analysis, 1 to 10 mg/kg body weight of STZ was selected for behavioural, molecular and histological studies. STZ administered fish had anxiety and stress-like behaviour in novel tank and light/dark preference tests. STZ-induced cognitive and memory deficits assessed using novel object recognition and spatial alternation tests. Further, expression of markers of amyloidogenic pathway (appa and bace1) were increased in terms of mRNA and protein levels in a time and dose dependent manner following STZ administration. However, expression of non-amyloidogenic pathway mediator (adam10) was reduced at both mRNA and protein level. Histological assessment using hematoxylin and eosin, and Nissl stain revealed loss of neurons in STZ administered fish. The ratio of phosphor-tauser396/total-tau was increased in STZ administered fish. Based on these findings, 5 mg/kg body weight of STZ was found to be most appropriate dose to exhibit sAD phenotype. Mass spectrometric analysis confirmed the presence of amyloid beta oligomers in brains of STZ administered fish. Transmission electron microscopy also showed the presence of higher order insoluble amyloid fibrils with twists. Immunohistochemical analysis revealed amyloid beta deposits in brain of STZ administered fish. Golgi-cox staining indicated decreased number of dendrites, whereas microglia had increased density, span ratio, soma area and lacunarity. The results of the present study demonstrate presence of AD hallmarks and phenotype in zebrafish 7 days post STZ administration (5 mg/kg). The study validates the potential of STZ-induced sAD in zebrafish as a reliable model for studying pathophysiology and rapid screening of therapeutic molecules against sAD.

Poly (DL-lactide-co-glycolide) based delivery systems for vaccines and drugs

Current vaccination and drug delivery strategies emphasize on the development of controlled release techniques for persistent and sustained effects. In the recent years, polymer based systems for the delivery of bioactive agents have gained considerable attention due to their marked adjuvanticity, established biodegradability and biocompatibility, excellent mechanical strength and controlled release profiles. This review deals with the potential applications of synthetic polymers mainly PLG polymers in delivery of vaccines and drugs.