Molecular and Morphological Characterization of a Taxol-Producing Endophytic Fungus, Gliocladium sp., from Taxus baccata

Sreekanth, D.,Sushim, G.K.,Syed, A.,Khan, B.M.,Ahmad, A. The Korean Society of Mycology 2011 Mycobiology Vol.39 No.3

The endophytic fungal populations of different tissues of Taxus baccata grown at high altitudes in West Bengal, India were explored. These isolated fungal populations represented different genera, which were screened for taxol production using immunoassay technique. The culture AAT-TS-$4_1$ that produced taxol was identified as Gliocladium sp. based on its cultural, morphological characteristics, internal transcribed spacer, and 18S rRNA sequence analysis. Kinetics of taxol production as a function of culture growth were investigated.

Ultra-sonication-assisted silver nanoparticles using <i>Panax ginseng</i> root extract and their anti-cancer and antiviral activities

Sreekanth, T.V.M.,Nagajyothi, P.C.,Muthuraman, P.,Enkhtaivan, G.,Vattikuti, S.V.P.,Tettey, C.O.,Kim, Doo Hwan,Shim, Jaesool,Yoo, Kisoo Elsevier 2018 Journal of photochemistry and photobiology Biology Vol.188 No.-

<P><B>Abstract</B></P> <P>A simple, inexpensive ultra-sonication method was used to synthesize quasi spherical silver nanoparticles (AgNPs) with an aqueous extract from <I>Panax ginseng</I> roots. This method has the advantages of being completely eco-friendly and allows increased reaction rates, uniform dispersal of the nanoparticles in liquids, and effective breaking of aggregates. Biomolecules present in plant extracts are often used to reduce metal ions to nanoparticles in a single-step green synthesis route. The formation of the AgNPs was characterized using UV–visible (UV–vis) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy- dispersive X-ray analysis (EDX), Fast Fourier Transform (FFT), and high-resolution transmission electron microscopy (HR-TEM). The formation of AgNPs (456 nm) was confirmed by UV–vis spectroscopy. HR-TEM analysis revealed that most of the AgNPs were quasi spherical with sizes ranging from approximately 5 to 15 nm. The crystalline nature of the AgNPs was confirmed by XRD, and the presence of elemental silver was confirmed by energy-dispersive X -ray analysis. The AgNPs showed dose-dependent cytotoxicity towards HeLa cells in vitro (3.88% at 0.005 M, 5.11% at 0.01 M, 7.52% at 0.015 M, 11.19% at 0.02 M, and 19.45% at 0.025 M) as revealed by sulforhodamine B assay. They were also shown to be virucidal against the influenza A virus (strain A/PR/8). Hence, the present facile, eco-friendly, and efficient method results in the synthesis of AgNPs that can act as an alternative biomaterial for future biomedical applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> AgNPs synthesized via green route using <I>Panax ginseng</I> root aqueous extract. </LI> <LI> AgNPs were spherical in shape, with a crystallite size of 5 to 15 nm. </LI> <LI> In addition, the green synthesized AgNPs were studied for in-vitro cytotoxic and antiviral activities. </LI> </UL> </P> <P><B>Graphical Abstract</B></P> <P>[DISPLAY OMISSION]</P>

Picrasma quassioides mediated cerium oxide nanostructures and their post-annealing treatment on the microstructural, morphological and enhanced catalytic performance

Sreekanth, T.V.M.,Dillip, G.R.,Lee, Y.R. Ceramurgica ; Elsevier Science Ltd 2016 CERAMICS INTERNATIONAL Vol.42 No.6

Cerium oxide (CeO<SUB>2</SUB>) nanostructures are an interesting metal oxide in catalysis owing to their unique redox properties and high mobility of oxygen vacancies at the surface. CeO<SUB>2</SUB> nanostructure was synthesized via a green route using an aqueous extract of Picrasma quassioides bark. Formation of ceria nanostructures were monitored by UV-vis absorption spectroscopy and Fourier transform infrared spectroscopy (FTIR). Annealing temperature-dependent crystallite size and lattice strain on the X-ray peak broadening of the CeO<SUB>2</SUB> nanostructures was determined by the size-strain plots. The application of the green synthesized CeO<SUB>2</SUB> nanostructures for the catalytic degradation of methylene blue by NaBH<SUB>4</SUB> was carried out. We demonstrated that the catalytic decomposition rate was gradually improved due to the increase of annealing temperature of CeO<SUB>2</SUB> nanostructure, and obtained highest performance at 600<SUP>o</SUP>C annealed sample. This is because of the significantly improved crystallinity of CeO<SUB>2</SUB> nanostructure at higher temperature, leading in a low density of crystalline defects and wide distribution of nanostructure with a large surface area to provide more active electrons (e<SUP>-</SUP>) for the decomposition of dye.

Green Synthesis: In-vitro Anticancer Activity of Silver Nanoparticles on Human Cervical Cancer Cells

Sreekanth, T. V. M.,Pandurangan, Muthuraman,Kim, Doo Hwan,Lee, Yong Rok Springer-Verlag 2016 Journal of cluster science Vol.27 No.2

<P>The development of an eco-friendly process for the synthesis of nanoparticles is an important and emerging area in the field of nanotechnology. Silver nanoparticles (AgNPs) were synthesized using Saccharina japonica extract and their cytotoxicity to cervical carcinoma cells was examined. The AgNPs were characterized by ultraviolet-visible absorption spectroscopy, Fourier transform infrared spectroscopy, high resolution-transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and selected area electron diffraction. The biosynthesized AgNPs were spherical in shape, and HeLa cells exposed to these NPs showed morphological changes, including rounding and loss of adherence. Fluorescence and confocal laser scanning microscopy revealed the characteristic apoptotic features such as reduction in nuclear volume and cytoplasm condensation.</P>

Determination of Band Alignment in the Synergistic Catalyst of Electronic Structure-Modified Graphitic Carbon Nitride-Integrated Ceria Quantum-Dot Heterojunctions for Rapid Degradation of Organic Pollutants

Sreekanth, T. V. M.,Nagajyothi, P. C.,Dillip, G. R.,Lee, Yong Rok American Chemical Society 2017 The Journal of Physical Chemistry Part C Vol.121 No.45

<P>We engineered novel heterojunction ceria (CeO<SUB>2</SUB>) QDs decorated on the surfaces of graphitic carbon nitride (g-C<SUB>3</SUB>N<SUB>4</SUB>) nanosheets by a facile in situ hydrothermal synthetic route. Using core-level/valence-band X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectroscopy, and work function measurements of the materials, we constructed the energy band alignment at the heterojunction. The band alignment has a Type-II alignment between organic (g-C<SUB>3</SUB>N<SUB>4</SUB>) and inorganic (CeO<SUB>2</SUB> QDs) semiconductors junction with valence/conduction band offsets (VBO/CBO) of −0.07/–0.31 eV. The calculated band alignment parameters of the heterojunction were compared with the experimental values of g-C<SUB>3</SUB>N<SUB>4</SUB>/CeO<SUB>2</SUB> QD composite and a new energy band diagram was proposed for the electronic structure-modified g-C<SUB>3</SUB>N<SUB>4</SUB>/CeO<SUB>2</SUB> QDs heterojunction. The newly constructed heterojunction is formed by carbon-vacancy-promoted g-C<SUB>3</SUB>N<SUB>4</SUB> coupled to lower defect-mediated (oxygen vacancies) CeO<SUB>2</SUB>, as determined by high-resolution XPS analysis. Moreover, the CeO<SUB>2</SUB> QD distribution on g-C<SUB>3</SUB>N<SUB>4</SUB> sheets using HR-TEM and the lattice parameter variations of g-C<SUB>3</SUB>N<SUB>4</SUB>/CeO<SUB>2</SUB> QDs as compared with those of pristine CeO<SUB>2</SUB> QDs from Rietveld refinement were investigated. To demonstrate the ability of the proposed heterojunction as a catalyst, we tested the catalytic activity of the composite junction for the degradation of Rhodamine B (RhB) in the presence of NaBH<SUB>4</SUB> as an example. The band alignment mechanism is useful for promoting the catalytic activity of the graphitic carbon nitride-based organic semiconductor and will attract researchers’ attention for developing new composite heterojunction catalysts for multifunctional applications.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2017/jpccck.2017.121.issue-45/acs.jpcc.7b08568/production/images/medium/jp-2017-08568k_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp7b08568'>ACS Electronic Supporting Info</A></P>

Determination of surface properties and Gutmann’s Lewis acidity–basicity parameters of thiourea and melamine polymerized graphitic carbon nitride sheets by inverse gas chromatography

Sreekanth, T.V.M.,Basivi, Praveen Kumar,Nagajyothi, P.C.,Dillip, G.R.,Shim, J.,Ko, T.J.,Yoo, K. Elsevier 2018 Journal of chromatography Vol.1580 No.-

<P><B>Abstract</B></P> <P>Melamine and thiourea-derived graphitic carbon nitrides (M-GCN/T-GCN) were synthesized and characterized. The surface properties were investigated using inverse gas chromatography (IGC) and compared. Net retention volumes of M-GCN and T-GCN were measured with <I>n</I>-alkanes (C<SUB>5</SUB>–C<SUB>10</SUB>) and polar probes. The London dispersive surface free energies ( γ s d ), calculated using Schultz and Dorris–Gray methods, decreased linearly with increasing temperature. The specific components of the enthalpy and entropy of adsorption for the polar probes were obtained using the Schultz, Dong, and Sawyer–Brookman methods. The Gutmann’s Lewis acid–base parameters, <I>K<SUB>a</SUB> </I> and <I>K<SUB>b</SUB> </I>, were determined using the surface free energy ( Δ G a S ) via these methods. The surface character ‘<I>S’</I> values (<I>K<SUB>b</SUB> </I>/<I>K<SUB>a</SUB> </I>) of M-GCN and T-GCN using the respective methods are 4.04, 3.78, and 5.08 and 4.11, 5.27, and 2.86. Hence, the surfaces contain more basic than acidic sites and could interact strongly with acidic media. Thus, IGC elucidates the surface charges of the GCN matrix resulting from surface chemical modification.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Graphitic carbon nitride was synthesized using two precursors, melamine and thiourea. </LI> <LI> Physicochemical properties were confirmed by XRD, XPS and BET. </LI> <LI> Inverse gas chromatography was employed to understand surface free energy of GCN. </LI> <LI> The London dispersive parameters were determined by Schultz/Dorris–Gray methods. </LI> <LI> The Lewis acid–base parameters, showing the more basic character of GCN. </LI> </UL> </P>

Circumferential Fusion through All-Posterior Approach in Andersson Lesion

Sreekanth Reddy Rajoli,Rishi Mugesh Kanna,Siddharth N. Aiyer,Ajoy Prasad Shetty,Shanmuganathan Rajasekaran 대한척추외과학회 2017 Asian Spine Journal Vol.11 No.3

Study Design: Retrospective case series. Purpose: To assess safety and efficacy of single stage, posterior stabilisation and anterior cage reconstruction through the transforaminal or lateral extra-cavitary route for Andersson lesions. Overview of Literature: Pseudoarthrosis in ankylosing spondylitis (Andersson lesion, AL) can cause progressive kyphosis and neurological deficit. Management involves early recognition and surgical stabilisation in patients with instability. However, the need and safety of anterior reconstruction of the vertebral body defect remains unclear. Methods: Twenty consecutive patients with AL whom presented with instability back pain and or neurological deficit were managed by single stage posterior approach with long segment pedicle screw fixation and anterior vertebral reconstruction. Radiological evaluation included- the regional kyphotic angle, measurement of anterior defect in computed tomography (CT) scan and the spinal cord status in magnetic resonance imaging. Radiological outcomes were assessed for fusion and kyphosis correction. Functional outcomes were assessed with visual analogue scale (VAS), ankylosing spondylitis quality of life (ASQoL) and Oswestry disability index (ODI). Results: The mean age of the patients was 50.1 years (male, 18; female, 2). The levels affected include thoracolumbar (n=12), lower thoracic (n=5) and lumbar (n=3) regions. The mean level of fixation was 6.2±2.4 vertebrae. The mean anterior column defect was 1.6±0.6 cm. The mean surgical duration, blood loss and hospital stay were 112 minutes, 452 mL and 6.2 days, respectively. The mean followup was 2.1 years. At final follow up, VAS for back pain improved from 8.2 to 2.4 while ODI improved from 62.7 to 18.5 (p <0.05) and ASQoL improved from 14.3±2.08 to 7.90±1.48 (p <0.05). All patients had achieved radiological union at a mean 7.2±4.6 months. The mean regional kyphotic angle was 27° preoperatively, 16.7° postoperatively and 18.1° at the final follow-up. Conclusions: Posterior stabilisation and anterior reconstruction with cage through an all-posterior approach is safe and can achieve good results in Andersson lesions.

Characterization and Application of the (PEO+KIO3+Plasticizer)Solid State Polymer Electrolyte System

T. Sreekanth 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.8

In the modern research domain, the study of polymer electrolytes is one of the extensively developing technologies for various applications. In this present study (PEO+KIO3+plasticizer), a specific approach is evaluated with respect to solid-state polymer electrolytes that were fabricated by using the solution casting method. The complexation of poly (ethylene oxide) (PEO), KIO3and the plasticizer (dimethyle formamide [DMF]) have been investigated by using X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The transport properties of these polymer electrolytes are studied by using the d.c. conductivity. The conductivity - temperature plots are obtained in the range of 304 - 373 K. The plots have two regions, one below and the other the melting point (Tm). Also the conductivity of the polymer electrolytes is found to increase with increasing in temperature. Electrochemical cells are fabricated and the open circuit voltage (OCV) is found to be 2.85 V and the short circuit current (SCC) to be 356 µA. The discharge characteristics are examined at a constant load of 100 kΩ.

Research Articles : Molecular and Morphological Characterization of a Taxol-Producing Endophytic Fungus, Gliocladium sp., from Taxus baccata

( D. Sreekanth ),( G. K. Sushim ),( A. Syed ),( B. M. Khan ),( A. Ahmad ) 한국균학회 2011 韓國菌學會誌 Vol.39 No.3

The endophytic fungal populations of different tissues of Taxus baccata grown at high altitudes in West Bengal, India were explored. These isolated fungal populations represented different genera, which were screened for taxol production using immunoassay technique. The culture AAT-TS-41 that produced taxol was identified as Gliocladium sp. based on its cultural, morphological characteristics, internal transcribed spacer, and 18S rRNA sequence analysis. Kinetics of taxol production as a function of culture growth were investigated.

Production, Purification, and Characterization of Taxol and 10-DABIII from a new Endophytic Fungus Gliocladium sp. Isolated from the Indian Yew Tree, Taxus baccata

D. Sreekanth,A. Syed,S. Sarkar,D. Sarkar,B. Santhakumari,A. Ahmad,M. I. Khan 한국미생물 · 생명공학회 2009 Journal of microbiology and biotechnology Vol.19 No.11