ABSTRACT
In an attempt to screen antagonistic microorganisms from marine environment for the management of bacterial pathogens in aquaculture, an isolate of actinomycete MCCB 110 was segregated based on its comparatively higher inhibitory property on Vibrio harveyi (MCCB 111) and profound luminescent inhibition. Based on the culture characteristics, cell wall fatty acid profile and the nucleotide sequence of the 16S rRNA gene (1495 bp), the isolate was identified as Nocardiopsis alba. Solvent extraction of the fermentation broth followed by TLC and HPLC analyses resulted in the isolation of a major fraction active against luminescent Vibrio harveyi. Partial characterization of this bioactive fraction based on spectroscopic data obtained from FT-IR, UV, MS-MS and 1H NMR analyses identified it as a substituted derivative of sterol, and was recognized to differ from those reportedly produced by the same genus. The fraction was not toxic to VERO cell line and shrimp haemocytes up to 1000 ppm tested. The study demonstrated the potential of the putative probiotic Nocardiopsis alba (MCCB 110) and its novel extra-cellular bioactive product in the management of Vibrio harveyi in aquaculture.
Subject(s)
Actinobacteria , Vibrio , Actinomyces , Aquaculture , Nocardiopsis , RNA, Ribosomal, 16S/genetics , Spectroscopy, Fourier Transform Infrared , SterolsABSTRACT
Palladium(II) ion-imprinted polymer (IIP) materials were synthesized by thermally polymerizing the ternary complexes of palladium(II) with amino (AQ) or hydroxy (HQ) or mercapto (MQ) derivatives of quinoline and 4-vinyl-pyridine. The functional and crosslinking monomers used during polymerization were 2-hydroxyethyl methacrylate (HEMA) and ethylene glycol dimethacrylate (EGDMA). 2,2'-Azobisisobutyronitrile (AIBN) and 2-methoxy ethanol were used as the initiator and porogen, respectively. The resulting polymer materials were dried in an oven at 80 degrees C, ground and sieved to obtain IIP particles which were then subjected to leaching with 50% (v/v) HCl to obtain the leached palladium(II) IIP particles. Control polymer (CP) particles were also prepared by following the above procedure described for IIP particles. The CP particles, unleached and leached AQ-based IIP particles were then characterized by IR, XRD and microanalysis studies. Analytical studies such as preconcentration of palladium(II) from dilute aqueous solutions and separation studies in the presence of selected noble and base metals which co-exist with palladium(II) in its ore or mineral deposits were systematically studied using CP and IIP particles and are compared. AQ-based IIP particles gave higher percent extraction and selectivity coefficients compared to HQ- or MQ-based IIP particles. Five replicate determinations of 25mug of palladium(II) present in 500ml of aqueous solution, when subjected to preconcentration and determination by iodide-Rhodamine 6G procedure gave a mean absorbance of 0.104 with a relative standard deviation of 2.25%. The detection limit corresponding to three times the standard deviation of the blank was found to be 5.0mug of palladium(II) per litre. The rebinding studies using AQ-, HQ- and MQ-based IIPs were carried out and were fitted to the different adsorption isotherm models, viz. Langmuir (L), Freundlich (F) and Langmuir-Freundlich (LF). These adsorption models were used for the evaluation of binding parameters and in elucidating the nature and type of bonding in the IIPs. The results of rebinding experiments showed discrimination between the three IIPs based on the donor atoms of the ligands.
ABSTRACT
This article explores the synthesis of styrene-divinyl benzene (DVB)/ethylene glycol dimethacrylate (EGDMA) polymers embedded with quinoline-8-ol (Q) or its dihalo derivatives by thermal means in the presence and absence of 4-vinyl pyridine (VP). The above-synthesized polymers were found to enrich cobalt and nickel present in admixtures. Of these, 5,7-dichloroquinoline-8-ol (DCQ) embedded styrene-EGDMA polymer particles enrich cobalt and nickel quantitatively from dilute aqueous solutions within 5 min of preconcentration time. Styrene-EGDMA, DCQ embedded styrene-EGDMA particles obtained by bulk polymerization and cobalt/nickel bonded polymers were characterized by FTIR, thermogravimetric analysis (TGA), elemental analysis and surface area studies. The use of these polymer particles obtained by bulk polymerization for the solid phase extractive preconcentration of cobalt and nickel was investigated in detail and explores the possibility of employing this procedure for the analysis of cobalt and nickel in soil and sediment samples using a simple, low cost and readily available flame atomic absorption spectrometric instrument was explored.
