Two 2’FY-RNA aptamers with distinct sequences were selected for specific binding to pyoverdine-Pf5 (PVD-Pf5), increasing chromophore fluorescence upon binding. They also recognized the peptide portion of pyoverdines, as shown by their differential specificity for related variants. Computational analysis and experimental data (NMM binding, CD spectra) identified G-quadruplex structures that were thermally metastable but reformed in the presence of PVD-Pf5. Further structural studies mainly with one aptamer revealed imino proton peaks in 1D H-NMR and pressure stability up to 2 kbar. Electrophoretic evidence identified dimeric G-quadruplexes formed by the 2’FY-RNA aptamers and their RNA equivalents. While cations were necessary for PVD-Pf5 binding, they were not required for G-quadruplex formation. Given the established role of G-quadruplexes as protein interaction sites, multimeric G-quadruplexes offer a potential framework for structure-based regulatory mechanisms in cellular RNAs. In addition to previously characterized multimeric G-quadruplexes, these aptamers contribute novel sequences that expand the repertoire of known multimeric G-quadruplexes.

Pyoverdines are iron-chelating siderophores employed by various pseudomonads to promote their growth in iron-limited environments, facilitating both beneficial and detrimental interactions with co-inhabiting microbes or hosts, including plants and animals. The fluorescent pseudomonads produce fluorescent pyoverdines comprised of a conserved central chromophore and a unique strain-specific peptidic side chain produced by non-ribosomal peptide synthetases. Pyoverdine Pf5 (PVD-Pf5) is produced by Pseudomonas protegens Pf-5, a species known for supporting plant growth and its involvement in plant pathogen control. To develop a means of exploring the dynamics of P. protegens activity in soil and in the rhizosphere, we selected DNA aptamers that specifically recognize PVD-Pf5 with high affinities. Two selected aptamers with only 16% identity in sequence were examined for structure and function. We found evidence that both aptamers form structures in their apo-forms and one aptamer has structural features suggesting the presence of a G-quadruplex. Although their tertiary structures are predicted to be different, both aptamers bind the target PVD-Pf5 with similar affinities and do not bind other siderophores, including the related pyoverdine, pseudobactin, produced by Pseudomonas sp. B10. One aptamer binds the pyoverdine peptide component and may also interact with the chromophore. This aptamer was integrated into a nanoporous aluminum oxide biosensor and demonstrated to successfully detect PVD-Pf5 and not to detect other siderophores that do not bind to the aptamer when evaluated in solution. This sensor provides a future opportunity to track the locations of P. protegens around plant roots and to monitor PVD-Pf5 production and movement through the soil.

Rhizosphere, the narrow region surrounding plant roots directly influenced by root exudates and the root associated microbiome, plays an important role in plant productivity and the rhizosphere is well known for stimulating microbial metabolic activities. How microbial communities interact to form stable, metabolically interconnected functional communities is an area of intense interest. The question remains on how microbially produced secreted molecules that function as intercellular communication signals shape the structure and function of microbial communities. Our goal is to detect and quantify signal molecules produced by microbes or plants in the root‐soil environment, spatially and temporarily. As a proof‐of‐concept, we are imaging diffusible extracellular microbial metabolites involved in a bacteria‐bacteria communication process called quorum‐sensing. Quorum‐sensing relies on the accumulation of high concentrations of signal molecules in the environment to control bacterial gene expression, influencing rhizosphere colonization and plant health. Local concentration of quorum sensing molecules are determined using aptamer based sensors. Aptamers that can specifically bind the desired signal molecules are selected through SELEX and immobilized on the surface of nano‐porous membranes. Binding of the signal molecules and aptamer covered surface results in changes in surface charge distribution and steric hinderance and thus modifying the transmembrane ionic transport. Changes in transmembrane impedance can be measured through electrochemical impedance spectroscopy methods to monitor local concentrations of signal molecules. Sensor responses were determined for different concentrations of signal molecules and results showed detection of C4‐HSL in a soil‐mimic solution with KD of 10 nM. We demonstrate that the quorum‐sensing signal molecule C4‐homoserine lactone and (C4‐HSL) can rapidly diffuse in a soil‐mimic gel, providing evidence for our use of a soil‐mimic for further aptasensor development and validation. The sensors were then inserted into soil mimic gel for monitoring C4‐HSL diffusion and the resulted impedance changes were used to determine the C4‐HSL concentration at different positions in the gel. Measurements of local C4‐HSL concentrations variation and numerical solution of diffusion equation were used to create 4D images of C4‐HSL molecule diffusion in the soil‐mimic gel.

The rhizosphere is a small region surrounding plant roots that is enriched in biochemicals from root exudates and populated with fungi, nematode, and bacteria. Interaction of rhizosphere organisms with plants is mainly promoted by exudates from the roots. Root exudates contain biochemicals that come from primary and secondary metabolisms of plants. These biochemicals attract microbes, which influence plant nutrition. The rhizosphere bacteria (microbiome) are vital to plant nutrient uptake and influence biotic and abiotic stress and pathogenesis. Pseudomonas is a genus of gammaproteobacteria known for its ubiquitous presence in natural habitats and its striking ecological, metabolic, and biochemical diversity. Within the genus, members of the Pseudomonas fluorescens group are common inhabitants of soil and plant surfaces, and certain strains function in the biological control of plant disease, protecting plants from infection by soilborne and aerial plant pathogens. The soil bacterium Pseudomonas protegens Pf-5 (also known as Pseudomonas fluorescensPf-5) is a well-characterized biological strain, which is distinguished by its prolific production of the secondary metabolite, pyoverdine. Knowledge of the distribution of P. fluorescens secretory activity around plant roots is very important for understanding the interaction between P. fluorescens and plants and can be achieved by real time tracking of pyoverdine. To achieve the capability of real-time tracking in soil, we have used a structure-switching SELEX strategy to select high affinity ssDNA and 2' F-Y-RNA aptamers with specificity for pyoverdine over other siderophores. Pyoverdines from various strains possess a conserved chromophore along with strain-specific peptide chain. Some of the isolated aptamers bind to chromophore of pyoverdine. These will identify pyoverdines from a variety of pseudomonads. Identification of aptamers that selectively bind the peptide portion of pyoverdine Pf-5 is underway. The identified aptamers that are broadly and narrowly specific for pyoverdines or Pf-5 will be optimized for integration into an electrochemical biosensor to track, in real time, P fluorescens activity and other pseudomonads in and around the rhizosphere.

The interaction of nucleic acids with their molecular targets often involves structural reorganization that may traverse a complex folding landscape. With the more recent recognition that many RNAs, both coding and noncoding, may regulate cellular activities by interacting with target molecules, it becomes increasingly important to understand how nucleic acids interact with their targets and how drugs might be developed that can influence critical folding transitions. We have extensively investigated the interaction of the Spinach2 and Broccoli aptamers with a library of small molecule ligands modified by various extensions from the imido nitrogen of DFHBI [(Z)-5-(3,5-difluoro-4-hydroxybenzylidene)-2,3-dimethyl-3,5-dihydro-4H-imidazol-4-one] that reach out from the Spinach2 ligand binding pocket. Studies of the interaction of these compounds with the aptamers revealed that polyfluorophenyl-modified ligands initiate a slow change in aptamer affinity that takes an extended time (half-life of ∼40 min) to achieve. The change in affinity appears to involve an initial disruption of the entrance to the ligand binding pocket followed by a gradual transition to a more defined structure for which the most likely driving force is an interaction of the gateway adenine with a nearby 2'OH group. These results suggest that polyfluorophenyl modifications might increase the ability of small molecule drugs to disrupt local structure and promote RNA remodeling.

Probiotics containing food supplements available in Bangladesh market were identified and collected for assessment. To assess their label claim, they were resuspended into sterile distilled water. Then, series dilutions of each sample solution were prepared and immediately plated out, in duplicate, into De Man Rogosa Sharpe (MRS) agar. These plates were then incubated at 37°C for 48 hours and colonies were counted. Viable cell numbers stated on the labels were compared with actual viable cell numbers. To assess the viability of the probiotics included in the products, probiotic strains were isolated from each of the four products and screened for inhibitory activity against six indicator strains. It was surprisingly found that although the viable cell numbers of all supplements were three to four log cycles lower than label claim of the products, however, this problem did not affect the inhibitory activity of the probiotic strains against indicator strains according to in vitro assessment. Legislation and regulation regarding prebiotic-probiotic containing products should be built up in Bangladesh to ensure quality products supply to the consumers. Moreover, manufacturers of probiotic containing products should take the responsibility for providing the consumer with scientifically and legally correct information.

Abstract Tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCD), flame retardant compounds used in epoxy resin circuit boards and upholstery, contaminate the environment and are found in human serum. Lymphocytes and monocytes are immune cells that, among other functions, secrete pro-inflammatory cytokines such as interleukin (IL)-1β, an important regulator of immune responsiveness and tissue growth and repair. Thus, if its levels are dysregulated, loss of proper immune function and increased invasiveness of tumors could ensue. This study examines whether exposures to varying concentrations (0.05–5.0 μM) of TBBPA and HBCD for 24 h, 48 h and 6 days interfere with the ability of immune cells to secrete IL-1β. The immune cell preparations examined were human natural killer (NK) cells, monocyte-depleted (MD) peripheral blood mononuclear cells (MD-PBMC) and PBMC. Both increased and decreased secretion of IL-1β from all three types of cell preparation were seen with TBBPA exposures and were dependent on concentration and length of exposure. TBBPA induced changes varied considerably from donor to donor. Exposure to HBCD from 0.5–5.0 μM caused increases in IL-1β secretion after all lengths of exposures in all cell preparations. The specific HBCD levels at which increases occurred varied among donors. Examinations of the signaling pathway(s) responsible for the elevated secretion of IL-1β after HBCD exposure were carried out in MD-PBMC cells. Results revealed that MAPK pathways (ERK1/2 and p38) appear to be the targets of HBCD that lead to increased IL-1β secretion from immune cells.

A simple, selective and rapid reversed phase high performance liquid chromatographic (RPHPLC) method for the analysis of Ciclesonide has been developed and validated.The separation was achieved from HPLC Column (Waters Symmetry C18 5 µ; 4.6 mm x 250 mm) with a mobile phase consisting of 85 volume of Ethanol with 15 volume of Millie-Q-Water at a flow rate of 1.10 ml/min with UV detection at 242 nm.The method is specific and it is observed that no interference with diluents.The proposed method is accurate with 99.6 % recovery for Ciclesonide and precise (% RSD of area of system precision, % RSD of assay of method precision and Intermediate precision are found to be 0.20 %, 0.20 % and 0.20 % respectively).From the linearity study the correlation coefficient is found to be 0.9999, which indicates that the method is linear over 10 % to 150 % range.The method is found robust for possible changes.Therefore, this method can be used as a more convenient and efficient option for the analysis of Ciclesonide to establish the quality of the drug substance during routine analysis with consistent and reproducible results.

In this study a simple, accurate, precise and sensitive high performance liquid chromatography (HPLC) method for the determination of Salbutamol and its degraded products in a Salbutamol sulphate inhaler have been developed and validated. The analysis was carried out using a Synergi 4 mu m Polar-RP 80A degrees 150mm x 4.6mm column with a mobile phase consisting 75: 25 of ammonium acetate buffer and methanol. The system suitability was assessed by analyzing standard solution containing Salbutamol. Syringe filter evaluation showed that 0.20 mu m syringe filter is suitable for intended use. From the specificity and forced degradation study, it was observed that no peak from placebo, impurities and potential degradation was co-eluting at the retention time of Salbutamol and the assay result of spiked sample was unaffected by the presence of placebo and known impurities. The Salbutamol peak passed the peak purity testing. The proposed method was accurate with 99. 58% recovery for Salbutamol and precise (% RSD of area of assay repeatability, intermediate precision and reproducibility were found 0.65%, 0.99% and 0.61% respectively). From the linearity study the correlation coefficient was found 0.999, indicating that the method is linear over 0.240 ppm to 8.640 ppm. And 95% confidence Interval was 99.14 to 99.97. The detection limit and quantitation limit were established as 0.0096 ppm (0.20%) and 0.048 ppm (1.00%) respectively. At LOQ level the % RSD of % recovery of 6 replicate injections was 4.59% and in accuracy study recovery was 101.52%. The method was found robust for possible changes. The sample solution was found stable up to 48 hours and mobile phase was found stable up to 7 days. Hence this method can be considered to assess the quality of the drug product during stability study and routine analysis with consistent and reproducible results.

The flower of Nymphaea nouchali is the national flower of Bangladesh and the plant parts are being used by the rural people of Bangladesh due their food and medicinal values. In this study the ethanol and chloroform extracts of Nymphaea nouchali leaves were investigated to evaluate their antioxidant property. Antioxidant property was evaluated by using total antioxidant capacity, DPPH ( 1,1- diphenyl-2-picrylhydrazyl) scavenging capacity, total phenol and flavonoid contents of the plant. In DPPH assay free radical scavenging activity of the extracts were evaluated comparing with ascorbic acid at 517 nm. The IC50 of ethanol extract of Nymphaea nouchalli is 10.102 +/- 0.23 mu g/ml and chloroform extract of Nymphaea nouchalli is 13.11 +/- 0.11 mu g/ml where as the IC50 of ascorbic acid was 19.89 +/- 0.22 mu g/ ml. Phenolic content was measured by Folin-Ciocalteu assay and is expressed as Gallic acid equivalents (GAE). The content of phenolic compound in the extracts correlates with the antioxidant activity, being higher in Ethanol extract of Nymphaea nouchalli (6.53 +/- 0.26 mg/g GAE) and lower in chloroform extract of Nymphaea nouchali (5.55 +/- 0.06mg/g GAE). And flavonoid contents were found 4.58 +/- 0.19 mg/ g quercetin equivalent for chloroform extract and 5.99 0.33mg/g quercetin equivalent for ethanol extract respectively. But both of the extracts contain almost similar amount of total antioxidant capacity having 2.75 +/- 0.12 mg/g ascorbic acid equivalent (AAE) for ethanolic extract and 2.69 +/- 0.09 mg/g AAE for chloroformic extract. Data of this study reveals that the medicinal plant Nymphaea nouchalli is rich source of antioxidants. Further investigations are required to isolate the antioxidant molecules to treat free radical associated diseases like cancer, neurological disorder, inflammation and cardiac disorder etc.

This study was designed to formulate and develop the tablet formulation of cefixime trihydrate 200 mg tablet and its in-vitro quality evaluation study. Dry granulation method was adopted for preparation of tablet using different excipients namely; cross-linked povidone, spray dried lactose, colloidal anhydrous silica, microcrystalline cellulose, pregelatinized starch, sodium lauryl sulphate, anhydrous calcium hydrogen phosphate, sodium stearyl fumerate and magnesium stearate in five different formulations (F-1 to F- 5). The granules for tabletting were evaluated for angle of repose, bulk density, compressibility index, total porosity and drug content etc. The tablets were also subjected to thickness, hardness, friability and in vitro release studies. Among the formulations, formula F-5 showed the satisfactory tablet properties and complied with the USP pharmacopoeial standard requirements for uniformity of dosage units and friability. The results of disintegration and dissolution studies indicated that formulations containing pregelatinized starch, microcrystalline cellulose and sodium lauryl sulphate showed lower disintegration time and higher percentage of dissolution at 45 minutes in comparison with other formulations and marketed products. But same formulation (F-5) with compacted grade of active ingredients exhibited lower percentage of dissolution and disintegration time than tablets prepared from micronized grade of active ingredients. Formula F-5 possessed good stability both in accelerated and long term storage condition for six months study.

During pregnancy iron demand is increased to meet requirements for nutrition of mother and fetus growth. For that, the probability of iron deficient anemia is increased during this time. Anemia also influences the health of the fetus as well as the health of mother. This study was conducted to 100 pregnant women. The data was collected from hospital patient record book and analyzed by the T test, Regration and Chi-square test with SPSS (version 11.5). The variables considered in this study were age, weight, height, BMI, ESR, deferential count of WBC and Hemoglobin concentration. The entire patient age range was 18-35 years but the incident rate was high in 20 years old patient. Average weight was 42.43kg but 40% patient had only <= 40kg, and BMI were (Mean +/- SD) 20.17 +/- 1.29916. The mean value of Hb conc. were 8.6470g/dl, but about 6% were severe (<7.0g/dl) and 79% were moderate (9.9-7.0g/dl) anemic. ESR was (Mean +/- SD) 36.59 +/- 25.25870mm/hr and 12% pregnant women had 40mm/hr ESR value. Average WBC count was in normal range (400-1000/mm(3)) and 28% had >1000/mm(3) WBC. We found 17% observed patient had >70% Neutrophil count and 63% of total observed patient had high lymphocyte count. The observe data revealed that low age had vital contribution to be anemic in pregnancy and infection may also was another factor that had vital impact to anemia in pregnancy.

A simple, selective and rapid reversed phase high performance liquid chromatographic (RPHPLC) method for the analysis of amlodipine in tablet has been developed and validated. The separation was achieved from octadecylsilyl silica gel, C18 (3.9 mm x 150 mm) column with a mobile phase consisting of HPLC grade acetonitrile, methanol and triethylamine solution (15: 35: 50) at a flow rate of 1ml/min with UV detection at 237nm at 30 degrees C column temperature. The method was specific and the assay result of spiked sample (with placebo) was unaffected by the presence of placebo (by comparison with the assay results obtained on unspiked sample). The proposed method was accurate with 100.29% recovery for amlodipine and precise (% RSD of area of system precision, % RSD of assay of method precision and intermediate precision were found 0.33%, 0.34% and 0.17% respectively). From the linearity study the correlation coefficient was found 0.9999, which indicated that the method was linear over 50% to 150% range. The method was found robust for possible changes. Therefore, this method can be used as a more convenient and efficient option for the analysis of amlodipine in tablet dosage form to establish the quality of the drug product during routine analysis with consistent and reproducible results.

Free radicals contribute to more than one hundred disorders in humans including atherosclerosis, arthritis, ischemia and reperfusion injury of many tissues, central nervous system injury, gastritis, cancer and AIDS.[1-2] Free radicals due to environmental pollutants, radiation, chemicals, toxins, deep fried and spicy foods as well as physical stress cause depletion of immune system antioxidants, change in gene expression and induce abnormality in proteins. Oxidation process is one of the most important routes for producing free radicals in food, drugs and even living systems. Catalase and hydroperoxidase enzymes convert hydrogen peroxide and hydroperoxides to non-radical forms and functions as natural antioxidants in human body. Due to depletion of immune system natural antioxidants in different maladies, consuming antioxidants as free radical scavengers may be necessary. [3-5]