A natural plant growth promoter,calliterpenone, enhances growth and biomass,carbohydrate, and lipid production in cyanobacterium Synechocystis PCC 6803

Cyanobacteria have evolved photosynthetic mechanisms in which solar energy is used to fix CO₂ into carbohydrates. The lipids from cyanobacteria can be converted to biodiesel by extraction–transesterification methods. The present study demonstrates the usefulness of the natural plant and microbial growth promoter calliterpenone from the plant Callicarpa macrophylla supplemented at three different doses (15, 25, 50 μL of a 0.01 mM solution) per 100 mL BG11⁺ medium for enhancing total biomass, carbohydrate, and lipid yields and reducing the surface-to-volume ratios of cells of Synechocystis PCC 6803. The enhanced total dried biomass, carbohydrate, and lipid production was 316.1, 140.34, and 130.76 %, respectively, higher than the control, and were obtained after 15 days of cultivation at the dose of 15 μL (0.01 mM) of calliterpenone per 100 mL BG11⁺ medium. A decrease in surface-to-volume ratio of cells from 1.19 to 0.84 compared to the control was also observed. Response surface methodology was used to optimize the doses of calliterpenone at different pH of growth media. An increase of 346.95, 187.2, and 134.46 % in biomass, carbohydrate, and lipid yields, respectively, was achieved after 10 days of cultivation in optimized BG11⁺ media at pH 7.5 and with 20 μL (0.01 mM) calliterpenone per 100 mL. Thus, this biomolecule can be exploited for higher yields of Synechocystis PCC 6803 in a relatively shorter culture time making this an attractive strategy for fuel production using this cyanobacterium.     

Native mitochondrial RNA-binding complexes in kinetoplastid RNA editing differ in guide RNA composition

Mitochondrial mRNAs in kinetoplastids require extensive U-insertion/deletion editing that progresses 3′-to-5′ in small blocks, each directed by a guide RNA (gRNA), and exhibits substrate and developmental stage-specificity by unsolved mechanisms. Here, we address compositionally related factors, collectively known as the mitochondrial RNA-binding complex 1 (MRB1) or gRNA-binding complex (GRBC), that contain gRNA, have a dynamic protein composition, and transiently associate with several mitochondrial factors including RNA editing core complexes (RECC) and ribosomes. MRB1 controls editing by still unknown mechanisms. We performed the first next-generation sequencing study of native subcomplexes of MRB1, immunoselected via either RNA helicase 2 (REH2), that binds RNA and associates with unwinding activity, or MRB3010, that affects an early editing step. The particles contain either REH2 or MRB3010 but share the core GAP1 and other proteins detected by RNA photo-crosslinking. Analyses of the first editing blocks indicate an enrichment of several initiating gRNAs in the MRB3010-purified complex. Our data also indicate fast evolution of mRNA 3′ ends and strain-specific alternative 3′ editing within 3′ UTR or C-terminal protein-coding sequence that could impact mitochondrial physiology. Moreover, we found robust specific copurification of edited and pre-edited mRNAs, suggesting that these particles may bind both mRNA and gRNA editing substrates. We propose that multiple subcomplexes of MRB1 with different RNA/protein composition serve as a scaffold for specific assembly of editing substrates and RECC, thereby forming the editing holoenzyme. The MRB3010-subcomplex may promote early editing through its preferential recruitment of initiating gRNAs.     

In Vitro,In Silico and In Vivo Studies of Ursolic Acid as an Anti-Filarial Agent

As part of our drug discovery program for anti-filarial agents from Indian medicinal plants, leaves of Eucalyptus tereticornis were chemically investigated, which resulted in the isolation and characterization of an anti-filarial agent, ursolic acid (UA) as a major constituent. Antifilarial activity of UA against the human lymphatic filarial parasite Brugia malayi using in vitro and in vivo assays, and in silico docking search on glutathione-s-transferase (GST) parasitic enzyme were carried out. The UA was lethal to microfilariae (mf; LC₁₀₀: 50; IC₅₀: 8.84 µM) and female adult worms (LC₁₀₀: 100; IC50: 35.36 µM) as observed by motility assay; it exerted 86% inhibition in MTT reduction potential of the adult parasites. The selectivity index (SI) of UA for the parasites was found safe. This was supported by the molecular docking studies, which showed adequate docking (LibDock) scores for UA (−8.6) with respect to the standard antifilarial drugs, ivermectin (IVM −8.4) and diethylcarbamazine (DEC-C −4.6) on glutathione-s-transferase enzyme. Further, in silico pharmacokinetic and drug-likeness studies showed that UA possesses drug-like properties. Furthermore, UA was evaluated in vivo in B. malayi-M. coucha model (natural infection), which showed 54% macrofilaricidal activity, 56% female worm sterility and almost unchanged microfilaraemia maintained throughout observation period with no adverse effect on the host. Thus, in conclusion in vitro, in silico and in vivo results indicate that UA is a promising, inexpensive, widely available natural lead, which can be designed and developed into a macrofilaricidal drug. To the best of our knowledge this is the first ever report on the anti-filarial potential of UA from E. tereticornis, which is in full agreement with the Thomson Reuter''s ‘Metadrug’ tool screening predictions.     

Synthesis and Characterization of Novel 2-Amino-Chromene-Nitriles that Target Bcl-2 in Acute Myeloid Leukemia Cell Lines

The anti-apoptotic protein Bcl-2 is a well-known and attractive therapeutic target for cancer. In the present study the solution-phase T3P-DMSO mediated efficient synthesis of 2-amino-chromene-3-carbonitriles from alcohols, malanonitrile and phenols is reported. These novel 2-amino-chromene-3-carbonitriles showed cytotoxicity in human acute myeloid leukemia (AML) cell lines. Compound 4g was found to be the most bioactive, decreasing growth and increasing apoptosis of AML cells. Moreover, compound 4g (at a concentration of 5 µM) increased the G2/M and sub-G1 (apoptosis) phases of AML cells. The AML cells treated with compound 4g exhibited decreased levels of Bcl-2 and increased levels of caspase-9. In silico molecular interaction analysis showed that compound 4g shared a similar global binding motif with navitoclax (another small molecule that binds Bcl-2), however compound 4g occupies a smaller volume within the P2 hot spot of Bcl-2. The intermolecular π-stacking interaction, direct electrostatic interactions, and docking energy predicted for 4g in complex with Bcl-2 suggest a strong affinity of the complex, rendering 4g as a promising Bcl-2 inhibitor for evaluation as a new anticancer agent.     

An Engineered Factor Va Prevents Bleeding Induced by Anticoagulant wt Activated Protein C

Objective

An increased risk of bleeding is observed in patients receiving activated protein C (APC), which may be a limiting factor for the application of novel APC therapies. Since APC''s therapeutic effects often require its cytoprotective activities on cells but not APC''s anticoagulant activities, an agent that specifically antagonizes APC''s anticoagulant effects but not its cytoprotective effects could provide an effective means to control concerns for risk of bleeding. We hypothesized that ^superFVa, an engineered activated FVa-variant that restores hemostasis in hemophilia could reduce APC-induced bleeding.

Approach and Results

^SuperFVa was engineered with mutations of the APC cleavage sites (Arg506/306/679Gln) and a disulfide bond (Cys609-Cys1691) between the A2 and A3 domains, which augment its biological activity and cause high resistance to APC. ^SuperFVa normalized APC-prolonged clotting times and restored APC-suppressed thrombin generation in human and murine plasma at concentrations where wild-type (wt) FVa did not show effects. Following intravenous injection of APC into BALB/c mice, addition to whole blood ex vivo of ^superFVa but not wt-FVa significantly normalized whole blood clotting. Blood loss following tail clip or liver laceration was significantly reduced when ^superFVa was administered intravenously to BALB/c mice prior to intravenous APC-treatment. Furthermore, ^superFVa abolished mortality (∼50%) associated with excessive bleeding following liver laceration in mice treated with APC.

Conclusions

Our results provide proof of concept that ^superFVa is effective in preventing APC-induced bleeding and may provide therapeutic benefits as a prohemostatic agent in various situations where bleeding is a serious risk.     

Product Development Studies on Surface-Adsorbed Nanoemulsion of Olmesartan Medoxomil as a Capsular Dosage Form

The present study aimed at development of capsular dosage form of surface-adsorbed nanoemulsion (NE) of olmesartan medoxomil (OLM) so as to overcome the limitations associated with handling of liquid NEs without affecting their pharmaceutical efficacy. Selection of oil, surfactant, and cosurfactant for construction of pseudoternary phase diagrams was made on the basis of solubility of drug in these excipients. Rationally selected NE formulations were evaluated for percentage transmittance, viscosity, refractive index, globule size, zeta potential, and polydispersity index (PDI). Formulation (F3) comprising of Capmul MCM® (10% v/v), Tween 80® (11.25% v/v), polyethylene glycol 400 (3.75% v/v), and double-distilled water (75% v/v) displayed highest percentage cumulative drug release (%CDR; 96.69 ± 1.841), least globule size (17.51 ± 5.87 nm), low PDI (0.203 ± 0.032), high zeta potential (−58.93 ± 0.98 mV), and hence was selected as the optimized formulation. F3 was adsorbed over colloidal silicon dioxide (2 ml/400 mg) to produce free-flowing solid surface-adsorbed NE that presented a ready-to-fill capsule composition. Conversion of NE to surface-adsorbed NE and its reconstitution to NE did not affect the in vitro release profile of OLM as the similarity factor with respect to NE was found to be 66% and 73% respectively. The %CDR after 12 h for optimized NE, surface-adsorbed NE, and reconstituted NE was found to be 96.69 ± 0.54, 96.07 ± 1.76, and 94.78 ± 1.57, respectively (p > 0.05). The present study established capsulated surface-adsorbed NE as a viable delivery system with the potential to overcome the handling limitations of NE.KEY WORDS: bioavailability, nanoemulsion, olmesartan medoxomil, oral