Queen Marys College

Chennai, India

Queen Marys College

Chennai, India
Time filter
Source Type

Malathi E.,Queen Marys College | Juliana Collette M.,Queen Marys College | Lyndsay Priscilla A.,Queen Marys College
Journal of the Marine Biological Association of the United Kingdom | Year: 2017

Eggs of Marphysa gravelyi are spawned in gelatinous masses and the developing larvae are harboured in them until they are ready to undergo settlement. In order to understand the function of the jelly mass, morphometric, histochemical, biochemical and antimicrobial analyses were performed. The observations indicate the fibrous jelly mass is composed of carbohydrate, protein and lipid, and size is correlated to number of eggs present within. Extracts from the jelly mass of Marphysa gravelyi exhibit inhibitory activity against Escherichia coli, Vibrio vulnificus and Candida albicans but no activity was seen against seven other microorganisms tested. The results show that the function of the jelly mass is to nourish the developing embryos, protect against desiccation and predation from macrofauna, and most importantly prevent the dispersal of the juveniles from the desirable habitat. Copyright © Marine Biological Association of the United Kingdom 2017

Karpagam S.,Queen Marys College | Sudhakar T.,Sathyabama University | Lakshmipathy M.,Sathyabama University
International Journal of Pharmacy and Pharmaceutical Sciences | Year: 2013

Objective: Pseudomonads are well known for their degradative abilities and play an important role in the environmental cleanup and they are opportunistic pathogens. The characteristic feature of Pseudomonas aeruginosa is the production of soluble pigments like pyocyanin, fluoresceins and exo-polysaccharides, a secondary metabolite that is produced in both solid and liquid culture media. The study aims at production and characterization of pigment pyocyanin and to evaluate its antimicrobial potential toward clinical isolates of fungi. Methods: Production of pyocyanin using Pseudomonas broth was validated. Extraction of the pigment was done by chloroform extraction method. Uv-visible absorption spectrum and Gas Chromatography were used to characterize the pigment and its components. Structural elucidation of pyocyanin was done using Nuclear Magnetic Resonance (NMR). Further, the antimicrobial activity of the pigment was evaluated using Cross streak method. Results: Pigment production was achieved after 24 h of incubation with a color change to bluish green. UV-visible spectra revealed a maximum absorption at 278nm characteristic of pyocyanin. The molecular weight of the compound was determined as 210.23kDa with a retention time of 11.94 min. NMR study revealed the presence of methyl group linked to condensed nitrogen aromatic ring. The antifungal activity of the pigment was found maximum toward Candida sp. and Cryptococcus neoformans. Conclusion: The properties of the pigment make it an important bioactive compound which has the ability to arrest the electron transport chain of fungi and exhibit antifungal activity towards Candida sp., and Cryptococcus neoformans.

Vimala T.,Queen Marys College | Poonghuzhali T.V.,Queen Marys College
Journal of Applied Pharmaceutical Science | Year: 2017

Objective: To evaluate the antimicrobial activity of different extracts of Hydroclathrus clathratus (C. Agardh) M. Howe against human bacterial and fungal pathogens. Methods: The antimicrobial activities of the extracts against various pathogens were tested by using agar well diffusion method. Results: Maximum activities were recorded by methanolic extract on P. aeruginosa (26.33±1.86mm), S.aureus (21.00±1.78mm), E. coli (19.32±0.89mm), B. subtilis (18.33±1.86mm) and K. Pneumoneae (18.14±1.50 mm). Hexane extract showed maximum antifungal activity against F. oxysporum (18.33±1.86mm) and ethyl acetate showed maximum activity against A. niger (18.33±2.73mm). While, methanolic extract showed more activity against A. flavus (18.00±3.22 mm), C. albicans (18.14±1.50mm) and Penicillium sp. (13.66±1.36mm). However, aqueous extract showed minimum inhibitory effect on the pathogens. Conclusions: Different solvent extracts of seaweeds used in the present study have shown significant anti-bacterial and anti-fungal action. The study offers opportunities for producing new types of bioactive compounds; however, the mechanism of inhibition and stability of the extracts still are not clear and more studies should be involved. © 2017 T. Vimala and T. V. Poonghuzhali.

Ilayaraja P.,Presidency College at Chennai | Srividya J.,Queen Marys College | Anbalagan G.,University of Madras
AIP Conference Proceedings | Year: 2017

Semiorganic L-histidinium hexaflurosilicate single crystal was grown by solvent evaporation solution growth technique. From PXRD, the crystallographic data were found as a=8.3496 Å, b=8.3376 Å, c=29.2973 Å and α= β=γ=90° with tetragonal crystal system (S. G. P41212). The crystalline perfection was studied by HRXRD. The molecular structure was identified using FT-IR and FTRaman spectral analysis. The crystal has 60% transparent in the visible region with a lower cutoff wavelength of 224 nm and optical band gap 4.15 eV. Laser damage threshold and frequency conversion efficiency were calculated as 3.89 GW/cm2 and 52 mV, respectively. Thermal studies indicate that the crystal was stable up to 260°C. © 2017 Author(s).

Surekha R.,Prathyusha Institute of Technology and Management | Sagayaraj P.,Loyola College | Ambujam K.,Queen Marys College
CrystEngComm | Year: 2014

l-Phenylalanine l-phenylalaninium bromide (LPLPB), an amino acid non-centrosymmetric crystal having a large second harmonic generation (SHG) efficiency, being 4.5 times that of KH2PO4 (KDP), has been successfully grown using a slow evaporation method employing a temperature gradient technique. The structure of the grown crystal was solved and refined by single-crystal X-ray diffraction, and this demonstrates that it belongs to a monoclinic system with the space group P21. The confirmation of its functional groups was recorded using Fourier transform infrared spectroscopy. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to study its thermal properties. The optical behaviour was examined and its optical constants were determined by UV-vis analysis. Dielectric spectroscopy reveals the dielectric nature of the grown crystal. The mechanical strength of the grown LPLPB was estimated by microhardness studies, and the Young's modulus of the grown LPLPB was calculated to be 3.310 × 10 10 N m-2. This journal is © the Partner Organisations 2014.

Sudhakar T.,Sathyabama University | Karpagam S.,Queen Marys College
International Journal of ChemTech Research | Year: 2013

The characterization of a Pseudomonas aeruginosa is the production of soluble pigment pyocyanin which has the property of antagonism towards bacteria and fungi. This strain was isolated from the clinical sample and the pigment was optimized by using various solid and liquid media. The pigment was extracted using chloroform resulting in a bluish colored compound and upon addition of 0.2 N HCl giving red color. Further, the pigment was partially purified using chromatographic technique and the maximum absorbance peak at 278 nm, characteristic of pyocyanin. The molecular weight of the compound was analyzed using Gas Chromatography - Mass Spectrometer (GC-MS) and found to be 210.23 kDa with an Rf value 11.94. The pigment was subjected to antagonistic activity against commonly encountered phytopathogens and its inhibitory concentration was observed at 64 μg/ml. The growth suppression phenomenon of this pigment isolated from the strain against fungi. This study reveals that the strain can be economically used as biocontrol agent against common phytopathogenic fungi.

John R.,University of Madras | Rajakumari R.,Queen Marys College
Nano-Micro Letters | Year: 2012

Zinc oxide (ZnO) doped with erbium at different concentrations was synthesized by solid-state reaction method and characterized by X-ray diffraction (XRD), scanning electron microscopic (SEM), UV- absorption spectroscopy, photoluminescence (PL) study and vibrating sample magnetometer. The XRD studies exhibit the presence of wurtzite crystal structure similar to the parent compound ZnO in 1% Er 3+ doped ZnO, suggesting that doped 3+ ions sit at the regular Zn 2+ sites. However, same studies spread over the samples with 3+ content>1% reveals the occurrence of secondary phase. SEM images of 1% 3+ doped ZnO show the polycrystalline nature of the synthesized sample. UV-visible absorption spectrum of 3+ doped ZnO nanocrystals shows a strong absorption peak at 388 nm due to ZnO band to band transition. The PL study exhibits emission in the visible region, due to excitonic as well as defect related transitions. The magnetization- field curve of 3+ doped ZnO nanocrystals showed ferromagnetic property at room-temperature.

Kalaiselvi D.,Queen Marys College | Jayavel R.,Anna University
Applied Physics A: Materials Science and Processing | Year: 2012

A semi-organic nonlinear optical L-proline dimercuricchloride (LPDMC) material has been synthesized. LPDMC single crystals were grown from aqueous solution by a slow cooling method. Good quality single crystals of size 19×6×3 mm 3 have been grown over a period of 3 weeks. The grown crystals have been subjected to single crystal X-ray diffraction analysis to determine the cell parameters. The title compound crystallizes in the triclinic system with a noncentrosymmetric space group P1 and with unit-cell parameters a=7.2742(4) Å, b=9.4472(5) Å, c=10.4767(6) Å, α=108.621(3)°, β=107.260(2)°, γ=97.353(2)° and volume=631.51(6) Å 3. Optical and dielectric properties of the crystals have been studied. The thermal stability of the crystals was determined by thermogravimetric analysis/differential thermal analysis. The second harmonic generation efficiency of the crystals was obtained by the classical powder technique using a Nd:YAG laser and it is found to be 2.5 times that of potassium dihydrogen phosphate. © 2012 Springer-Verlag.

Dhanalekshmi K.I.,Queen Marys College | Meena K.S.,Queen Marys College
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2014

Core-shell type Ag@TiO2 nanoparticles were prepared by one pot simultaneous reduction of AgNO3 and hydrolysis of Ti (IV) isopropoxide and Ag@SiO2 core-shell nanoparticles were prepared by Stober's method. They were characterized by absorption, XRD, and HR-TEM techniques. XRD patterns show the presence of anatase form of TiO2 and amorphous form of SiO2 and the noble metal (Ag). High resolution transmission electron microscopy measurements revealed that their size is below 50 nm. The antibacterial properties of Ag@TiO2 and Ag@SiO2 core-shell nanoparticles against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were examined by the agar diffusion method. As a result E. coli and S. aureus were shown to be substantially inhibited by Ag@TiO 2 and Ag@SiO2 core-shell nanoparticles. These results demonstrated that TiO2 and SiO2 supported on the surface of Ag NPs without aggregation was proved to have enhanced antibacterial activity. © 2014 Elsevier B.V. All rights reserved.

Dhanalekshmi K.I.,Queen Marys College | Meena K.S.,Queen Marys College
Materials Science and Engineering C | Year: 2016

Ag@ZrO2 core-shell nanoparticles were prepared by one pot simultaneous reduction of AgNO3 and hydrolysis of zirconium (IV) isopropoxide. The formation of core-shell nanoparticles was confirmed by absorption, XRD, and HR-TEM techniques. The antibacterial activity of Ag@ZrO2 core-shell nanoparticles against Escherichia coli and Staphylococcus aureus and the antifungal properties against Candida albicans, Candida glabrata, Aspergillus Niger and Aspergillus flavus were examined by the agar diffusion method. DNA intercalation studies were carried out in CT-DNA. As a result ZrO2 supported on the surface of AgNPs not only prevented aggregation, but also proved to have enhanced antimicrobial activity and DNA intercalation than the Ag nanoparticles. © 2015 Elsevier B.V. All rights reserved.

Loading Queen Marys College collaborators
Loading Queen Marys College collaborators