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| Articles
by
D. Dhanasekaran |
Total Records (
3 ) for
D. Dhanasekaran |
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K. Rajesh
,
K.C. Padmavathi
,
A. Ranjani
,
P.M. Gopinath
,
D. Dhanasekaran
and
G. Archunan
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The silver nanoparticles (AgNPs) were synthesized using extracellular metabolites
of Streptomyces sp. GRD (JX512257). The characterization of the synthesized
AgNPs was performed by UV-VIS spectrophotometer, FT-IR, Scanning Electron Microscopy
(SEM) and X-ray diffraction spectroscopy. The synthesised silver nanoparticles
have maximum absorption at 450 nm in UV-VIS spectrophotometer. The FTIR data
showed prominent peak in 3401.33, 2922.30, 2364.79, 2116.07, 1643.17, 1375.53,
1424.69 and 1324.03 cm-1 ranges. The SEM analysis showed that the
AgNPs were spherical and slightly elongated in nature. The XRD peaks revealed
the crystalline nature of the silver nanoparticles and the size of the synthesized
nanoparticles was found to be in the range of 10-15 nm. The biologically synthesized
silver nanoparticles were treated against the mosquito larvae of Culex quinquefasciatus
and Aedes aegypti. The LC50 value of synthesized nanoparticle
was identified as 1.23 and 1.19 mg L-1 for Culex quinquefasciatus
and Aedes aegypti larvae. Further, LC90 values are also
identified as 2.97 and 4.93 mg L-1, for Culex quinquefasciatus
and Aedes aegypti respectively. Hence the present work suggests that
the nanoparticles from Streptomyces sp. GRD would be appropriate for
developing a biological control method of mosquito larval population. |
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A. Suresh
,
R. Praveen Kumar
,
D. Dhanasekaran
and
N. Thajuddin
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The systematic study was conducted on the microalgal flora of Western Ghats and other parts of Eastern Ghats revealed a rich wetland algal resource for biotechnological exploration. The present study reveals with the diversity of microalgal flora in the region of Kodaikanal (10°14' N, 77°28' E), Gudalur (9°19'N 77°12'E), Agasthiyar falls (9°58'N, 78°10'E) and Kolli hills (10°12'N, 77°56'E) located in Western and Eastern Ghats of Tamilnadu, India collected in May 2011. In total, 97 species of micro algae belonging to three taxonomic groups were identified, of which 41 species belonging to Cyanophyceae, 38 species from Chlorophyceae and 18 species from Bacillariophyceae. The predominant species in Cyanophyceae were Aphanothece microscopica, Chroococcus minutus, Coelospharium dubium, Hydrococcus rivularism, Oscillatoria princeps, Nostoc muscorum, Nostoc puncteforme, Nostoc commune, Gleotricha gausii, Calothrix braunii, Rivellaria sp., Tolypothrix tenuis, Scytonema schmidtii, whereas in Chlorophyceae, Chlorella sp., Scenedesmus sp., Pediastrum duplex, Cosmarium consperum, Euastrum elagans, Micrasterias americana and in Bacillariophyceae, Navicula hallophyla, Rhophaldia gebrella, Fragellaria intermedia, Pinnularia virdis, Nitzchia palliate. Physicochemical nature of water samples were analyzed and correlated with the total microalgal diversity. Based on the correlation coefficient data, the micro algae showed positive relationship with dissolved oxygen, salinity, nutrients and negative relationship with temperature and turbidity. The species diversity index (H'), Species Richness (SR) and species evenness (J') were calculated and analyzed for microalgal population dynamic variation in the Western and Eastern Ghats. |
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D. Dhanasekaran
,
P. Sivamani
,
A. Panneerselvam
,
N. Thajuddin
,
G. Rajakumar
and
S. Selvamani
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Twenty six antibiotic producing Streptomyces were isolated from soils of Cuddalore Tamil Nadu, India and were evaluated for their ability to inhibit plant pathogenic Rhizoctonia solani in vitro. It was found that the isolates having pathogenic inhibitory ability and also controls Rhizoctonia solani damping off in tomato in interested field soils. The Streptomyces isolates tested significantly reduced damping off severity in tomato. A variation in their effect on plant disease severity, percentage dead plants and plant biomass in the presence of the pathogen, was observed among the isolates. |
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