<Emphasis Type="Italic">In Vitro</Emphasis> and <Emphasis Type="Italic">In Vivo</Emphasis> Evaluation of Proniosomes Containing Celecoxib for Oral Administration

The objectives of this research were to prepare celecoxib proniosomes and evaluate the influence of proniosomal formulation on the oral bioavailability of the drug in human volunteers. A new proniosomal delivery system for a poorly water-soluble drug such as celecoxib was developed and subjected to in vitro and in vivo studies. Proniosomes were prepared by sequential spraying method, which consisted of cholesterol, span 60, and dicetyl phosphate in a molar ratio of 1:1: 0.1, respectively. The average entrapment percent of celecoxib proniosome-derived niosomes was about 95%. The prepared proniosomes showed marked enhancement in the dissolution of celecoxib as compared to pure drug powder. The bioavailability of 200 mg single dose of both celecoxib proniosomal formulation and a conventional marketed celecoxib capsule was studied in human volunteers. The obtained results show that the proniosomal formulation significantly improved the extent of celecoxib absorption than conventional capsule. The mean relative bioavailability of the proniosomal formulation to the conventional capsule was 172.06 ± 0.14%. The mean T _max for celecoxib was prolonged when given as proniosomal capsule. There was no significant difference between the values of K _el and t _1/2 for both celecoxib preparations. In conclusion, the proniosomal oral delivery system of celecoxib with improved bioavailability was established.     

Physical Characterization of 1,3-dipropyl-8-cyclopentylxanthine (CPX)

1,3-dipropyl-8-cyclopentylxanthine (CPX) has been shown to stimulate in vitro CFTR activity in ∆F508 cells. Data from a phase I study demonstrated erratic bioavailability and no measurable clinical response to oral CPX. One cause for its poor bioavailability may have been dissolution rate limited absorption, but there is little published physicochemical data on which to base an analysis. The objective of this study was to determine the solubility and solid-state characteristics of CPX. CPX is a weak acid with pKa of 9.83 and water solubility at pH 7.0 of 15.6 μM. Both laureth-23 and poloxamer 407 increased the apparent water solubility linearly with increasing concentrations. CPX exists in two crystal forms, one of which (form II) has been solved. Form II is a triclinic crystal with space group P1 and calculated density of 1.278 g/cm³. X-ray powder diffraction and differential scanning calorimetry studies (DSC) indicated that CPX crystals prepared at room temperature were mixtures of forms I and II. DSC results indicated a melting point of approximately 195°C for form I and 198°C for form II. Thermogravimetric analysis indicated no solvent loss upon heating. Dynamic water vapor sorption data indicated no significant water uptake by CPX up to 90% RH. Analysis of the data indicates that CPX may not be amenable to traditional formulation approaches for oral delivery.     

Introduction of 2,4-dichlorophenoxyacetic acid into soil with solvents and resulting implications for bioavailability to microorganisms

Slow equilibration of introduced chemicals through tortuous pore space limits uniform substrate distribution in soil biodegradation studies. The necessity of introducing poorly soluble xenobiotics via organic solvents, the volume of which is minimized to limit toxicity, likely also affects xenobiotic distribution. Our objective was to investigate relative effects of carrier solvent choice and volume on xenobiotic distribution, apparent solvent toxicity, and soil degradation of 2,4-dichlorophenoxy acetic acid. Incubations using four carrier solvents ranging in properties showed that the fraction of 2,4-D mineralized was a hyperbolic function of solvent volume used (0.02–10 μl g⁻¹), attributed to compensating effects of herbicide bioavailability and solvent toxicity. Substrate concentration influenced mineralization of herbicide introduced with organic carriers, but not water. Fraction of material readily desorbed increased when water was the carrier. Results suggest that solvent toxicity should be balanced with uniformity of substrate distribution when using organic carriers in soils. Substrate bioavailability is a ubiquitous issue in terrestrial microbiology research, thus limitations observed herein broadly apply to microbiology questions about introduced substances in soil. We advocate the development of tools to characterize variable conditions among soil compartments, estimates of substrate bioavailability, and linkage of this information to microbial data.     

Bioadhesive Microspheres for Bioavailability Enhancement of Raloxifene Hydrochloride: Formulation and Pharmacokinetic Evaluation

Raloxifene hydrochloride (R-HCl), a BCS class II drug, remains a mainstay in the prevention and pharmacologic therapy of osteoporosis. Its absolute bioavailability, however, is 2% due to poor solubility and extensive first pass metabolism. The present study describes two simultaneous approaches to improve its bioavailability, complexation of R-HCl with cyclodextrin(s), and formulation of mucoadhesive microspheres of the complex using different proportions of carbopol and HPMC. Microspheres were pale yellow in color, free-flowing, spherical, and porous in outline. The particle size ranged between 3 and 15 μm, and entrapment efficiency was found to be within 81.63% to 87.73%. A significant improvement in the solubility of R-HCl was observed, and it differed with the combination of excipients used. X-ray diffraction and differential scanning calorimetry studies revealed that enhancement in drug solubility was resulted due to a change in its crystallinity within the formulation. Microspheres possessed remarkable mucoadhesion and offered controlled drug release, lasting up to 24 h. They produced a sharp plasma concentration–time profile of R-HCl within 30 min post-administration to Wistar rats. [AUC]_0–24 h was found to be 1,722.34 ng h/ml, and it differed significantly to that of pure drug powder (318.28 ng h/ml). More than fivefold increase in AUC and more than twofold increase in MRT were observed. FT-IR studies evidenced no interaction among drug and excipients. The results of this study showed that mucoadhesive microspheres could be a viable approach to improve the pharmacokinetic profile of R-HCl.     

Glyceryl Monooleate/Poloxamer 407 Cubic Nanoparticles as Oral Drug Delivery Systems: I. In Vitro Evaluation and Enhanced Oral Bioavailability of the Poorly Water-Soluble Drug Simvastatin

Glyceryl monooleate (GMO)/poloxamer 407 cubic nanoparticles were investigated as potential oral drug delivery systems to enhance the bioavailability of the water-insoluble model drug simvastatin. The simvastatin-loaded cubic nanoparticles were prepared through fragmentation of the GMO/poloxamer 407 bulk cubic-phase gel using high-pressure homogenization. The internal structure of the cubic nanoparticles was identified by cryo-transmission electron microscopy. The mean diameter of the cubic nanoparticles varied within the range of 100–150 nm, and both GMO/poloxamer 407 ratio and theoretical drug loading had no significant effect on particle size and distribution. Almost complete entrapment with efficiency over 98% was achieved due to the high affinity of simvastatin to the hydrophobic regions of the cubic phase. Release of simvastatin from the cubic nanoparticles was limited both in 0.1 M hydrochloride solution containing 0.2% sodium lauryl sulfate and fasted-state simulated intestinal fluid with a total release of <3.0% at 10 h. Pharmacokinetic profiles in beagle dogs showed sustained plasma levels of simvastatin for cubic nanoparticles over 12 h. The relative oral bioavailability of simvastatin cubic nanoparticles calculated on the basis of area under the curve was 241% compared to simvastatin crystal powder. The enhancement of simvastatin bioavailability was possibly attributable to facilitated absorption by lipids in the formulation rather than improved release.     

Development of Budesonide Microparticles Using Spray-Drying Technology for Pulmonary Administration: Design, Characterization, In Vitro Evaluation, and In Vivo Efficacy Study

The purpose of this research was to generate, characterize, and investigate the in vivo efficacy of budesonide (BUD) microparticles prepared by spray-drying technology with a potential application as carriers for pulmonary administration with sustained-release profile and improved respirable fraction. Microspheres and porous particles of chitosan (drug/chitosan, 1:2) were prepared by spray drying using optimized process parameters and were characterized for different physicochemical parameters. Mass median aerodynamic diameter and geometric standard deviation for conventional, microspheres, and porous particles formulations were 2.75, 4.60, and 4.30 μm and 2.56, 1.75, and 2.54, respectively. Pharmacokinetic study was performed in rats by intratracheal administration of either placebo or developed dry powder inhalation (DPI) formulation. Pharmacokinetic parameters were calculated (Ka, Ke, T _max, C _max, AUC, and Vd) and these results indicated that developed formulations extended half life compared to conventional formulation with onefold to fourfold improved local and systemic bioavailability. Estimates of relative bioavailability suggested that developed formulations have excellent lung deposition characteristics with extended T _1/2 from 9.4 to 14 h compared to conventional formulation. Anti-inflammatory activity of BUD and developed formulations was compared and found to be similar. Cytotoxicity was determined in A549 alveolar epithelial cell line and found to be not toxic. In vivo pulmonary deposition of developed conventional formulation was studied using gamma scintigraphy and results indicated potential in vitro–in vivo correlation in performance of conventional BUD DPI formulation. From the DPI formulation prepared with porous particles, the concentration of BUD increased fourfold in the lungs, indicating pulmonary targeting potential of developed formulations.     

Chronotherapeutically Modulated Pulsatile System of Valsartan Nanocrystals—an <Emphasis Type="Italic">In Vitro</Emphasis> and <Emphasis Type="Italic">In Vivo</Emphasis> Evaluation

The objective was to improve the dissolution of valsartan by developing valsartan nanocrystals and design a pulsed release system for the chronotherapy of hypertension. Valsartan nanocrystals were prepared by sonication—anti-solvent precipitation method and lyophilized to obtain dry powder. Nanocrystals were directly compressed to minitablets and coated to achieve pulsatile valsartan release. Pharmacokinetic profiles of optimized and commercial formulations were compared in rabbit model. The mean particle size and PDI of the optimized nanocrystal batch V4 was reported as 211 nm and 0.117, respectively. DSC and PXRD analysis confirmed the crystalline nature of valsartan in nanocrystals. The dissolution extent of valsartan was markedly enhanced with both nanocrystals and minitablets as compared to pure valsartan irrespective of pH of the medium. Core minitablet V4F containing 5% w/w polyplasdone XL showed quickest release of valsartan, over 90% within 15 min. Coated formulation CV4F showed two spikes in release profile after successive lag times of 235 and 390 min. The pharmacokinetic study revealed that the bioavailability of optimized formulation (72.90%) was significantly higher than the commercial Diovan tablet (30.18%). The accelerated stability studies showed no significant changes in physicochemical properties, release behavior, and bioavialability of CV4F formulation. The formulation was successfully designed to achieve enhanced bioavailability and dual pulsatile release. Bedtime dosing will more efficiently control the circadian spikes of hypertension in the morning.     

Radioprotective effects of hawthorn against genotoxicity induced by gamma irradiation in human blood lymphocytes

The radioprotective effect of hawthorn (Crataegus microphylla) fruit extract was investigated in cultured blood lymphocytes from human volunteers. Peripheral blood samples were collected from five human volunteers 10 min before and 1, 2 and 3 h after a single oral ingestion of 500 mg hawthorn powder extract. At each time point, the whole blood was exposed in vitro to 150 cGy of cobalt-60 gamma irradiation, and then the lymphocytes were cultured with mitogenic stimulation to determine the micronuclei in cytokinesis-blocked binucleated cell. The lymphocytes in the blood samples collected after extract ingestion exhibited a significant decrease in the incidence of binucleated cells containing micronuclei as compared to similarly irradiated lymphocytes collected prior to extract ingestion. The maximum decrease in the frequency of micronuclei-containing cells was observed at 1 h after ingestion of Hawthorn extract (on average a 44% decrease). These data suggest that it may be possible to use Hawthorn extracts in personnel exposed to radiation in order to protect lymphocytes from radiation effects.     

Influence of endophytic fungal elicitation on production of inophyllum in suspension cultures of <Emphasis Type="Italic">Calophyllum inophyllum</Emphasis> L.

The influence of dried cell powder and culture filtrates of endophytic fungi on production of inophyllum in cell suspension cultures of leaf- and stem-derived callus of Calophyllum inophyllum was investigated. Two fungi, Nigrospora sphaerica and Phoma spp., endophytic to C. inophyllum, were isolated from leaf tissues, and were identified by both 18S rRNA gene amplification and sequencing. Elicitation of suspension cultures of both callus types of C. inophyllum with dried cell powder and culture filtrates of both fungi consistently elicited production of inophyllum A, B, C, and P. In comparison to stem-derived callus, suspension cultures of leaf-derived callus enhanced production of most inophyllum. Of the four inophyllum studied, the highest production of inophyllum A, C, and P was achieved in elicited suspension cultures of leaf-derived callus. Suspension cultures of stem-derived callus enhanced production only of inophyllum B. When suspension cultures of leaf-derived callus were elicited with 40 mg dried cell powder of Phoma spp., a level of 751-fold (6.84 mg/100 g elicited biomass) of inophyllum A was produced, compared to control. Whereas, a level of 414-fold (6.22 mg/100 g elicited biomass) of inophyllum B was produced when suspension cultures of stem-derived callus were elicited with 20 mg dried cell powder of N. sphaerica. When compared to control, a 10% culture filtrate of N. sphaerica in suspension cultures of leaf-derived callus elicited inophyllum C and P production by 928-fold (7.43 mg/100 g elicited biomass) and 750-fold (1.5 mg/100 g elicited biomass), respectively.     

Bioavailability assessment of ketoprofen incorporated in gelled self-emulsifying formulation: A technical note

Conclusion  Based on the results of the present study, it is apparent that the gelled SEF containing KPF did not significantly alter its bioavailability as compared with that of an immediate release solid dosage form when administered to human volunteers by the oral route. Published: August 10, 2005.     

Development of Pusa 5SD for seed dressing and Pusa Biopellet 10G for soil application formulations of Trichoderma harzianum and their evaluation for integrated management of dry root rot of mungbean (Vigna radiata)

Various seed dressing and soil application formulations were developed from Trichoderma viride, T. virens and T. harzianum to increase the shelf life of bio-formulations used to manage dry root rot (Rhizoctonia bataticola) of mungbean (Vigna radiata), a major yield limiting factor in mungbean production. The shelf life of the formulations developed in the present study was monitored by counting colony forming units (cfu) up to 25 months of storage at room temperature (26 ± 8 °C). A newly developed seed dressing formulation, Pusa 5SD based on peat powder (47.5%), Sabudana powder (Manihot esculenta) (47.5%) and carboxymethyl cellulose (5%) and a newly developed soil application formulation, Pusa Biopellet (PBP) based on sodium alginate, aluminium silicate, Sabudana powder and tap water (1:5:5:100 w/w/w/v) exhibited longer shelf life. Another formulation Pusa Biogranule (PBG) based on wheat and pulse brans varied in cfu counts during different periods of storage. Pusa 5SD could be used up to 25 months of storage while PBP 10G and PBG 5 could be used up to 15 months of storage (>10⁵ cfu). The efficacy of the formulations was evaluated in pot experiments against the disease. In these experiments, T. harzianum based PBP 10G and PBG 5 for soil application, and Pusa 5SD for seed treatment were found to be superior to others in reducing the dry root rot incidence, and increasing the seed germination and shoot and root lengths. However, a combination of soil application of PBP 10G (T. harzianum) and seed treatment with T. harzianum based Pusa 5SD + carboxin was found superior to the use of any of these formulations alone in reducing the dry root rot incidence (87.2%) and increasing the seed germination (43.0%), shoot length (40.3%), root length (37.0%) and grain yield (54.6%) of mungbean crop over those of untreated control under sick field conditions.     

Evaluation of Stability and Biological Activity of Solid Nanodispersion of Lambda-Cyhalothrin

Pesticides are essential agrochemicals used to protect plants from diseases, pests and weeds. However, the formulation defects of conventional pesticides cause food toxicity and ecological environmental problems. In this study, a novel, efficient and environmentally friendly formulation of lambda-cyhalothrin, a solid nanodispersion, was successfully developed based on melt-emulsification and high-speed shearing methods. The solid nanodispersion presented excellent advantages over conventional pesticide formulations in such formulation functions as dispersibility, stability and bioavailability. The formulation is free of organic solvents, and the use of surfactant is reduced. Therefore, the application of the solid nanodispersion in crop production will improve efficacy and reduce the occurrence of both pesticide residues in food and environmental pollution from pesticides.     

A Dry Powder Formulation of Liposome-Encapsulated Recombinant Secretory Leukocyte Protease Inhibitor (rSLPI) for Inhalation: Preparation and Characterisation

Inhaled recombinant secretory leukocyte protease inhibitor (rSLPI) has shown potential for the treatment of inflammatory lung conditions. Rapid inactivation of rSLPI by cathepsin L (Cat L) and rapid clearance from the lungs has limited clinical efficacy to date. Previous studies by us have shown that encapsulation of rSLPI within1,2-dioleoyl-sn-glycero-3-[phospho-L-serine]/cholesterol (DOPS/Chol) liposomes protects rSLPI against Cat L inactivation in vitro. Liquid DOPS–rSLPI preparations were found to be unstable upon long-term storage and nebulisation. The aim of this study was therefore to develop a method of manufacture for preparing DOPS–rSLPI liposomes as a dry powder for inhalation. DOPS–rSLPI dry powders were lyophilised and subsequently micronised with a novel micronisation aid. The effects of formulation and processing on rSLPI stability, activity, and uniformity of content within the powders were characterised. Using D-mannitol as the micronisation aid, dry powder particles in the inhalable size range (<5 μm) were prepared. By optimising process parameters, up to 54% of rSLPI was recovered after micronisation, of which there was no significant loss in anti-neutrophil elastase activity and no detectable evidence of protein degradation. Aerosolisation was achieved using a dry powder inhaler, and mass median aerodynamic diameter (MMAD) was evaluated after collection in a cascade impactor. Aerosolisation of the DOPS–rSLPI dry powder yielded 38% emitted dose, with 2.44 μm MMAD. When challenged with Cat L post-aerosolisation, DOPS–rSLPI dry powder was significantly better at retaining a protective function against Cat L-induced rSLPI inactivation compared to the aqueous DOPS–rSLPI liposome dispersion and was also more stable under storage.     

Effect of green tea powder (<Emphasis Type="Italic">Camellia sinensis</Emphasis> L. cv. Benifuuki) particle size on <Emphasis Type="Italic">O</Emphasis>-methylated EGCG absorption in rats; The Kakegawa Study

Tea polyphenols, e.g., (-)-epigallocatechin-3-O-(3-O-methyl gallate (EGCG3”Me), (-)-epigallocatechin-3-O-gallate (EGCG), (-)-epigallocatechin (EGC), (-)-epicatechin-3-O-gallate (ECG), and (-)-epicatechin (EC), are believed to be responsible for the beneficial effects of tea. ‘Benifuuki’, a tea (Camellia sinensis L.) cultivar grown in Japan, is rich in the anti-allergic molecule epigallocatechin-3-O-(3-O-methyl) gallate (EGCG3”Me). Pulverized Benifuuki green tea powder (BGP) is more widely distributed than leaf tea in Japan. Japanese people mix their pulverized tea with water directly, whereas it is common to drink leaf tea after extraction. However, few studies of the effects of BGP particle size on polyphenol bioavailability have been performed. This study was conducted to investigate the absorption of catechins in rats after the intragastric administration of Benifuuki green tea. Therefore, we assessed the plasma concentrations of catechins following the ingestion of BGP with different mean particle sizes (2.86, 18.6, and 76.1 μm) or Benifuuki green tea infusion (BGI) as a control in rats. The bioavailabilities of EGCG3”Me, EGCG, ECG, EGC, and EC were analyzed after the oral administration of a single dose of Benifuuki green tea (125 mg/rat) to rats. The plasma concentrations of tea catechins were determined by HPLC analysis combined with of electrochemical detection (ECD) using a coulometric array. The AUC (area under the drug concentration versus time curve; min μg/mL) of ester-type catechins (EGCG3”Me, EGCG, and ECG) for the BGP 2.86 μm were significantly higher than those in the infusion and 18.6 and 76.1 μm BGP groups, but the AUC of free-type catechins (EGC and EC) showed no differences between these groups. Regarding the peak plasma level of EGCG3”Me adjusted for intake, BGP 2.86 μm and BGI showed higher values than the BGP 18.6 and 76.1 μm groups, and the peak plasma levels of the other catechins displayed the same tendency. The present study demonstrates that the bioavailability of ester-type catechins (EGCG and ECG) can be improved by reducing the particle size of green tea, but the plasma level of EGCG3”Me in the BGI group was similar to that in the BGP 2.86 μm group. This result suggests that drinking Benifuuki green tea with a particle size of around 2 μm would deliver the anti-allergic EGCG3”Me and the anti-oxidant EGCG efficiently.     

Novel dry powder preparations of whole inactivated influenza virus for nasal vaccination

The purpose of these studies was to enhance mucosal and systemic antibody production in response to increased local residence time of a whole inactivated influenza virus administered as a dry powder nasal vaccine formulation. Spray-freeze-drying (SFD) particles suitable for nasal delivery were characterized for physico-chemical properties and stability. Mucoadhesive compounds (MA) were characterized for their effects on nasal residence time of vaccine powders in rats compared with published in vitro data and elicited immune responses. SFD particles (D(50) = 26.9 microm) were spherical with a specific surface area of 1.25 m(2)/g. Thermal analysis indicated SFD powders were amorphous and demonstrated improved stability with respect to liquid formulations under various storage conditions. In vitro physico-chemical studies and in vivo scintigraphic imaging experiments indicated sodium alginate (SA) and carboxymethylcellulose-high molecular weight (CMC-HMW) powder formulations most significantly increased residence time in Brown Norway rats. Intramuscular delivery provided equivalent serum antibody titers to intranasal (IN) powder without MA, in the presence of CMC-HMW, SA, and hydroxypropyl methylcellulose (HPMC-HMW) after initial dosing and all formulations except IN powder with chitosan after boosting. IN liquid provided equivalent serum antibody titers to all IN powders after the initial vaccination and significantly greater serum antibody titers than IN powder with chitosan after boosting. Trends were consistent between residence time studies and immune response; however, no statistically significant differences between powder and liquid formulations were observed. It was concluded that enhanced serum and mucosal antibody responses were elicited by a dry powder nasal vaccine, specifically, administered in the presence of sodium alginate.     

Cyclodextrin-Based Nanosponges for Delivery of Resveratrol: <Emphasis Type="Italic">In Vitro</Emphasis> Characterisation,Stability, Cytotoxicity and Permeation Study

The aim of this work was to increase the solubility, stability and permeation of resveratrol by complexation with cyclodextrin-based nanosponges (NS). Nanosponges are recently developed hyper-cross-linked cyclodextrin polymers nanostructured to form three-dimensional networks; they are obtained by reacting cyclodextrin with a cross-linker such as carbonyldiimidazole. They have been used to increase the solubility and stability of poorly soluble actives. This study aimed at formulating complexes of resveratrol with β-cyclodextrin nanosponges in different weight ratios. DSC, FTIR and X-ray powder diffraction (XRPD) studies confirmed the interaction of resveratrol with NS. XRPD showed that the crystallinity of resveratrol decrease after encapsulation. The particle sizes of resveratrol-loaded NS are in between 400 to 500 nm with low polydispersity indices. Zeta potential is sufficiently high to obtain a stable colloidal nanosuspension. TEM measurement also revealed a particle size around 400 nm for NS complexes. The in vitro release and stability of resveratrol complex were increased compared with plain drug. Cytotoxic studies on HCPC-I cell showed that resveratrol formulations were more cytotoxic than plain resveratrol. The permeation study indicates that the resveratrol NS formulation showed good permeation in pigskin. The accumulation study in rabbit mucosa showed better accumulation of resveratrol NS formulation than plain drug. These results signify that resveratrol NS formulation can be used for buccal delivery and topical application.     

Preparation and Bioavailability Assessment of SMEDDS Containing Valsartan

A self-microemulsifying drug delivery system (SMEDDS) has been developed to enhance diffusion rate and oral bioavailability of valsartan. The solubility of valsartan was checked in different oils, surfactants, and cosurfactants and ternary phase diagrams were constructed to evaluate the microemulsion domain. The valsartan SMEDDS was prepared using Capmul MCM (oil), Tween 80 (surfactant), and polyethylene glycol 400 (cosurfactant). The particle size distribution, zeta potential, and polydispersity index were determined and were found to be 12.3 nm, −0.746, and 0.138, respectively. Diffusion rate of valsartan was measured by in vitro dialysis bag method using phosphate buffer pH 6.8 as diffusion media. Developed high-performance liquid chromatography method was used to determine drug content in diffusion media. Oral bioavailability of valsartan SMEDDS was checked by using rabbit model. Results of diffusion rate and oral bioavailability of valsartan SMEDDS were compared with those of pure drug solution and of marketed formulation. Diffusion of valsartan SMEDDS showed maximum drug release when compared to pure drug solution and marketed formulation. The area under curve and time showed significant improvement as the values obtained were 607 ng h/mL and 1 h for SMEDDS in comparison to 445.36 and 1.36 h for market formulation suggesting significant increase (p < 0.01) in oral bioavailability of valsartan SMEDDS.     

Characterization of the iron-regulated <Emphasis Type="Italic">desA</Emphasis> promoter of <Emphasis Type="Italic">Streptomyces pilosus</Emphasis> as a system for controlled gene expression in actinomycetes

Background  

The bioavailability of iron is quite low since it is usually present as insoluble complexes. To solve the bioavailability problem microorganisms have developed highly efficient iron-scavenging systems based on the synthesis of siderophores that have high iron affinity. The systems of iron assimilation in microorganisms are strictly regulated to control the intracellular iron levels since at high concentrations iron is toxic for cells. Streptomyces pilosus synthesizes the siderofore desferrioxamine B. The first step in desferrioxamine biosynthesis is decarboxylation of L-lysine to form cadaverine, a desferrioxamine B precursor. This reaction is catalyzed by the lysine decarboxylase, an enzyme encoded by the desA gene that is repressed by iron.     

Preparation, Characterization and Evaluation of Marsupsin–Phospholipid Complex

The aim of this research was to formulate Marsupsin–phospholipid complex (M–P Complex) in attempt to increase the bioavailability of marsupsin and to characterize this new formulation along with its evaluation. Marsupsin–phospholipid complex was formulated by mechanical dispersion method. In this new formulation, complex formation was confirmed by carrying out transmission electron microscopy (TEM), IR, ¹H-NMR and RP-HPLC analysis. TEM showed M–P Complex diameter range of 0.05–0.5 μm. The entrapment efficiency of M–P Complex was found to be 44%. In vitro release study revealed its first order release profile. Mean blood serum concentration vs time curve of marsupsin was of first order after oral administration of M–P Complex in albino rabbits which clearly showed remarkably increased bioavailability of M–P Complex than standardized marsupsin. The average value of C _max and T _max of M–P Complex were found to be 3.02 mg/ml and 10.2 h, respectively. Hence the findings demonstrate that complexing marsupsin with phospholipids results in better oral bioavailability and improved biological response than free form of standardized marsupsin.     

Management of root-knot nematode,Meloidogyne incognita and soil borne fungus,Fusarium oxysporum in cucumber using three bioagents under polyhouse conditions

Complex diseases caused by Meloidogyne incognita and Fusarium fungus in cucumber is the most destructive disease under polyhouses. The experiment was conducted in the polyhouse of the Department of Horticulture, CCS HAU, Hisar, Haryana, India during summer season (2015–16) to evaluate the potential of bacterial and fungal biocontrol agents against Meloidogyne incognita and Fusarium oxysporum f. sp. cucumerinum in cucumber. Bioagents - Trichoderma viride (Tv), Pseudomonas fluorescence (Pf), Purpureocillium lilacinum (Pl) were taken 10 and 20 g kg⁻¹ seed and bioagents liquid formulation, 10- and 15-ml kg⁻¹ seed, were mixed with the potted soil. Chemical as well as untreated check were also maintained. All the treatments significantly improved the plant growth parameter, viz., shoot length (SL), root length (RL), fresh shoot weight (FSW), fresh root weight (FRW), dry shoot weight (DSW) and dry root weight (DRW) as compared to untreated check. However, significant reduction in nematode population and maximum improvement in plant growth parameter was recorded with carbofuran followed by higher dose of bioagents liquid formulation. Among the bioagents, bioagents liquid formulation was most effective in suppressing root knot nematode galling (43 / root system) and final population in soil (131 J₂s / 200 cc soil) and fungus wilt incidence (25 %) at 30th day of after germination and significantly improved the plant growth parameters - shoot length (147.3 cm), fresh shoot weight (55.6 g), dry shoot weight (22.51 g) and dry root weight (4.50 g) from other bioagents. Bioagents liquid formulation was effective in suppression of root-knot nematode and fungus complex disease than the powder formulations of bioagents. More studies should be needed in future to evaluate the efficacy of bioagents as seed treatments and soil applications under field conditions.