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Antagonistic properties of seagrass associated streptomyces ***-1:A source for anthraquinone rich compound

Asian Pacific Journal of Tropical Medicine 2012年第11期5卷 887-890页

作者： s.ravikumar M.Gnanadesigan A.saravanan N.Monisha V.Brindha s.Muthumari school of Marine sciences Department of Oceanography and Coastal Area StudiesAlagappa UniversityThondi campusThondi-623 409Ramanathapuram DistrictTamilnaduIndia Department of Microbiology Selvamm Arts and Science CollegeNamakkal-637 003TamilnaduIndia Department of Biotechnology AVS College of Arts and ScienceSalemTamilnaduIndia Department of Biotechnology Thassim Beevi Abdul Kader College for WomenKilakarai-623 517Ramanathapuram DistrictTamilnaduIndia Departemt of Biotechnology Meenakshi Ramasamy Arts and Science CollegeThathanur-621 804Ariyalur DistrictTamilnaduIndia

Objective:To identify the antibacterial potential of seagrass(syringodium isoetifoliutn) associate microbes against bacterial ***:Eumeration of microbial associates were analyzed with leaf and root samples of syringodium *** and MBC were calculated for bacterial pathogens with microbial *** and GC-Ms analysis were calculated for Actinomycetes sp.(Act01) which was the most ***:Of the isolated microbial associates phosphatase producing bacterial isolates were identified as maximum [(26l.78±35.09) CFU×10~4/g]counts in root *** the selected microbial isolates Actinomycete sp(Act01) showed broad spectrum of antibacterial activity against antibiotic resistant and fish bacterial *** analysis of Act01 showed maximum identities(99%) with the streptomyces sp.(GU5500072).The 16s rDNA secondary structure of Act01 showed the free energy values as -366.3 kkal/*** GC-Ms analysis Act01 showed maximum retention value with 23.742 RT and the corresponding chemical class was identified as 1,4-dihydroxy-2-(3- hydroxybutyl)-9,10-anthraquinone 9,***:In conclusion,streptomyces sp. (GU045544.1) from syringodium isoetifolium could be used as potential antibacterial agent.

关键词： Actinomycetes sp. MIC MBC Phylogenetic analysis syringodium isoetifolium

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基于非天然氨基酸的蛋白质合成研究进展

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食品与发酵工业 2024年第12期50卷 336-342页

作者：赵梅刘馨远陈洋商洁丛宏日马豪 ravikumar Yuvaraj 齐向辉江苏大学食品与生物工程学院江苏镇江212013

蛋白质是生命体的重要组成部分,几乎参与了所有的生命活动。通常情况下生物体中蛋白质由20种天然氨基酸组成,但随着现代科技的飞速发展,人们对医疗、食品、材料等方面的需求日渐增大,这些蛋白质已经无法满足多样化的应用需求。随着非天... 详细信息

蛋白质是生命体的重要组成部分,几乎参与了所有的生命活动。通常情况下生物体中蛋白质由20种天然氨基酸组成,但随着现代科技的飞速发展,人们对医疗、食品、材料等方面的需求日渐增大,这些蛋白质已经无法满足多样化的应用需求。随着非天然氨基酸及其合成的蛋白质的优异性能,使得利用非天然氨基酸改造蛋白质的技术逐渐成为研究热点。非天然氨基酸有着不同于天然氨基酸的侧链基团,可以给蛋白质带来新的性质与功能。该文基于对非天然氨基酸及非天然蛋白质的研究,首先介绍了以化学及生物的手段合成非天然氨基酸的方法,同时对化学及生物法的优劣势及未来的发展前景进行了总结;然后介绍了将非天然氨基酸掺入蛋白质的几种热门方法;接着对非天然氨基酸及其合成蛋白质的应用在酶的改造、科研以及医疗方面进行了列举和描述;最后对这项技术未来的发展进行了展望与总结。

关键词：非天然氨基酸非天然蛋白质细胞代谢工程遗传密码扩展酶的改造蛋白药物改造

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A study on the Protective Effect of Cynodon dactylon Leaves Extract in Diabetic Rats

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Biomedical and Environmental sciences 2011年第2期24卷 190-199页

作者： Karthik D ravikumar s Department of Biotechnology PRIST University

Objective To investigate the antidiabetic, antioxidant and hypolipidemic efficacy of Cynodon dactylon in diabetic rats. Methods The experimental rats were randomly divided into three groups： Group I： control; Group II： Alloxan diabetic, untreated; and Group III： Alloxan diabetic treated with ethanolic extract of C. dactylon leaves （450 mg/kg bw）. Experimental diabetes was induced by alloxan in a single dose of 150 mg/kg bw. Results A significant diminution of fasting blood sugar level was observed and also significant increase in HDL and decrease （P0.05） in cholesterol, triglyceride, LDL and VLDL were observed after 15 days of treatment. The investigation also revealed, the activities of AsT, ALT, ALP, AP, LDH, and CPK （P0.05） were decreased in the extract‐supplemented group. The significant decrease in protein content and sOD, CAT, GPx, and GsH （P0.05） activity and increase in LPO in plasma were found to be ameliorated after treatment. Conclusion Our result supports the fact that administration of extract of C. dactylon leave is able to reduce hyperglycemia and hyperlipidemia risk and also reduced the oxidative stress in diabetic rats.

关键词： Cynodon dactylon Ethanolic extract GC‐Ms Alloxan diabetes Antidiabetic Antioxidant Lipid profile Enzyme profile

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Improved strength and ductility of high alloy containing Al–12Zn–3Mg–2.5Cu alloy by combining non-isothermal step rolling and cold rolling

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International Journal of Minerals,Metallurgy and Materials 2017年第2期24卷 179-185页

作者： V.V.ravikumar s.Kumaran Department of Metallurgical and Materials Engineering National Institute of TechnologyTamil Nadu 620015India

Al-12Zn-3Mg-2.5Cu alloy was prepared using a liquid metallurgy route under the optimized conditions. A sample cut from the ingot was rolled non-isothermally from 400℃ to 100℃ in 100℃ steps, with 15% reduction in thickness; it was then cold rolled isothermally at room temperature for 85% reduction. The cold-rolled alloys were characterized by electron microscopy, hardness test, and tensile test to elucidate their structural evolution and evaluate their mechanical behavior. In the results, the cast alloy consists of a-aluminum and various intermetallic compounds. These compounds are segregated along the grain boundaries, which makes the alloy difficult to roll at room tem- perature. The combined effect of non-isothermal step rolling and cold rolling results in the nano/microsized compounds distributed uniformly in the matrix. The hardness is substantially increased after rolling. This increase in hardness is attributed to the ultra-fine grain size, fine-scale intermetallic compounds, and structural defects （e.g., dislocations, stacking faults, and sub-grains）. The ultimate tensile strength of the rolled alloy is approximately 628 MPa with 7% ductility.

关键词： aluminum zinc magnesium copper alloys non-isothermal cold rolling mechanical properties intermetallic compounds struc-ture defects

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Co-evolution of nuclear rings,bars and the central intensity ratio of their host galaxies

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Research in Astronomy and Astrophysics 2020年第2期20卷 15-20页

作者： s.Aswathy C.D.ravikumar Department of Physics University of Calicut

Using a sample of 13 early-type spiral galaxies hosting nuclear rings,we report remarkable correlations between the properties of the nuclear rings and the central intensity ratio(CIR) of their host *** CIR,a function of intensity of light within the central 1.5 and 3 arcsec region,is found to be a vital parameter in galaxy evolution,as it shares strong correlations with many structural and dynamical properties of early-type galaxies,including mass of the central supermassive black hole(sMBH).We use archival HsT images for aperture photometry at the centre of the galaxy image to compute the *** observe that the relative sizes of nuclear rings and ring cluster surface densities strongly correlate with the *** correlations suggest reduced star formation in the centres of galaxies hosting small and dense nuclear *** scenario appears to be a consequence of strong bars as advocated by the significant connection observed between the CIR and bar *** addition,we observe that the CIR is closely related with the integrated properties of the stellar population in the nuclear rings,associating the rings hosting older and less massive star clusters with low values of ***,the CIR can serve as a crucial parameter in unfolding the coupled evolution of bars and rings as it is intimately connected with both their properties.

关键词： galaxies:evolution galaxies:formation galaxies:photometry galaxies:spiral galaxies:starburst

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In vitro antiplasmodial activity of methanolic extracts from seaweeds of south West Coast of India

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Asian Pacific Journal of Tropical Medicine 2011年第11期4卷 862-865页

作者： s.ravikumar G Ramanathan M Gnanadesigan A Ramu V Vijayakumar school of Marine sciences Department of Oceanography and Coastal Area StudiesAlagappa UniversityThondi CampusThondi - 623 409Ramanathapuram DistrictTamil NaduIndia Department of Microbiology V.H.S.N.College.Virudhunagar DistrictTamil NaduIndia school of Chemistry Department of Inorganic ChemistryMadurai Kamaraj UniversityMadurai DistrictTamil NaduIndia

Objective:To identify the in vitro antiplasmodial activity of seaweed plants against Plasmodium falciparum ***:A total of eight seaweeds were collecled from Kanvakumari district,Tainilnadu,*** in vitro antiplasmodial activity was performed in 96 well plates against Plasmodium falciparum,and preliminary phytochemcial analysis were performed for the ***:Of the selected plants Enteromorpha intestinalis(2.61%) showed maximum percentage of *** minimum concentration of inhibitory(IC_(50)) value was observed with Chaetomorpha antennina[(26.37±4.14)μg/ml.]further,the positive controls such as chloroquine and artemether showed antiplasmodial activities(IC_(50)) with(19.10±5.93) and(6.03±0.21)μg/mL concentrations,*** preliminary phytochemical analysis of the seaweed extracts showed a variety of phytochemical constituents such as carboxylic acids,phenols,protein, resins,steroids and ***:The antiplasmodial activity of the seaweed extract might due to the presence of sugars and phenolic *** the present findings,it is concluded that,the seaweed extract of Chaetomorpha antennina can be further used as a putative antiplasmodial drugs in near future.

关键词： Antiplasmodial activity IC_(50) Phytochemical seaweeds Plasmodium falciparum

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Anticancer property of sediment actinomycetes against MCF-7 and MDA-MB-231 cell lines

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Asian Pacific Journal of Tropical Biomedicine 2012年第2期2卷 92-96页

作者： ravikumar s Fredimoses M Gnanadesigan M school of Marine sciences Department of Oceanography and Coastal Area StudiesAlagappa UniversityThondi CampusThondi-623 409Ramanathapuram District Department of Biotechnology K.S.Rangasamy College of Arts & ScienceThiruchengodu- 637209Namakkal District

ObjectiveTo investigate the anticancer property of marine sediment actinomycetes against two different breast cancer cell *** vitro anticancer activity was carried out against breast (MCF-7 and MDA-MB-231) cancer cell lines. Partial sequences of the 16s rRNA gene, phylogenetic tree construction, multiple sequence analysis and secondary structure analysis were also carried out with the actinomycetes *** the selected five actinomycete isolates, ACT01 and ACT02 showed the IC50 value with (10.13±0.92) and (22.34±5.82) μg/mL concentrations, respectively for MCF-7 cell line at 48 h, but ACT01 showed the minimum (18.54±2.49 μg/mL) level of IC50 value with MDA-MB-231 cell line. Further, the 16s rRNA partial sequences of ACT01, ACT02, ACT03, ACT04 and ACT05 isolates were also deposited in NCBI data bank with the accession numbers of GQ478246, GQ478247, GQ478248, GQ478249 and GQ478250, respectively. The phylogenetic tree analysis showed that, the isolates of ACT02 and ACT03 were represented in group I and III, respectively, but ACT01 and ACT02 were represented in group II. The multiple sequence alignment of the actinomycete isolates showed that, the maximum identical conserved regions were identified with the nucleotide regions of 125 to 221st base pairs, 65 to 119th base pairs and 55, 48 and 31st base pairs. secondary structure prediction of the 16s rRNA showed that, the maximum free energy was consumed with ACT03 isolate (-45.4 kkal/mol) and the minimum free energy was consumed with ACT04 isolate (?7.6 kkal/mol).ConclusionsThe actinomycete isolates of ACT01 and ACT02 (GQ478246 and GQ478247) which are isolated from sediment sample can be further used as anticancer agents against breast cancer cell lines.

关键词： Actinomycetes Breast cancer MCF–7 MDA–MB–231 Phylogenetic tree Anticancer property Multiple sequence analysis secondary structure analysis sediment Anticaner agent Cell line

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Electron Paramagnetic Resonance and Optical Absorption studies on Copper Ions in Mixed Alkali Cadmium Phosphate Glasses

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Journal of Materials science & Technology 2009年第4期25卷 531-534页

作者： G. Giridhar M. Rangacharyulu R.V.s.s.N. ravikumar P. sambasiva Rao Department of Physics Acharya Nagarjuna University Department of Chemistry Pondicherry University

Electron paramagnetic resonance （EPR） and optical absorption studies were carried out at room temperature on copper doped mixed alkali cadmium phosphate （LiNaCdP） glasses to understand the nature and symmetry of dopant. Three samples with varying concentrations of alkali ions have been prepared. The spin Harniltonian parameters obtained from room temperature EPR spectra are： gli=2.437, 9⊥=2.096, A‖=117×10-4 cm-1, A⊥=26×10-4 cm-1 for LiNaCdP1, g‖=2.441, g⊥=2.088, A‖=121×10-4 cm-1, A⊥=25×10-4 cm-1 for LiNaCdP2and g‖=2.433,g⊥=2.096, A‖=125×10 4cm-1, A⊥=32×10-4cm-1 for LiNaCdP3. TheseEPR results indicate that the dopant Cu2＋ ion enters the glass matrix into a tetragonally elongated octahedral site. The bonding parameters evaluated by correlating optical and EPR data suggest that bonding between the central metal ion and ligands is partially covalent. The mixed alkali effect in cadmium phosphate glasses was reported.

关键词： Glasses Electron paramagnetic resonance (EPR) Optical properties

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structural and photoluminescence studies on europium-doped lithium tetraborate(Eu:Li2B4O7)single crystal grown by microtube Czochralski(μT-Cz)technique

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Chinese Physics B 2016年第5期25卷 429-433页

作者： A Kumaresh R Arun Kumar N ravikumar U Madhusoodanan B s Panigrahi K Marimuthu M Anuradha GRD Centre for Materials Research PSG College of TechnologyCoimbatoreIndia Department of Physics PSG College of TechnologyCoimbatoreIndia Radiation safety Division Indira Gandhi Centre for Atomic ResearchKalpakkamIndia Department of Physics Gandhigram Rural UniversityDindigulIndia PsG Institute of Advanced studies CoimbatoreIndia

Rare earth europium（Eu（3＋））-doped lithium tetraborate（Eu：Li_2B_4O_7） crystal is grown from its stoichiometric melt by microtube Czochralski pulling technique（μT-Cz） for the first time. The grown crystals are subjected to powder x-ray diffraction（PXRD） analysis which reveals the tetragonal crystal structure of the crystals. UV–vis–NIR spectral analysis is carried out to study the optical characteristics of the grown crystals. The crystal is transparent in the entire visible region, and the lower cutoff is observed to be at 304 nm. The existence of BO_3 and BO_4 bonding structure and the molecular associations are analyzed by Fourier transform infrared（FTIR） spectroscopy. The results of excitation and emission-photoluminescence spectra of europium ion incorporated in lithium tetraborate（LTB） single crystal reveal that the observations of peaks at 258,297, and 318 nm in the excitation spectra and peaks at 579, 591, 597, 613, and 651 nm are observed in the emission *** chromaticity coordinates are calculated from the emission spectra, and the emission intensity of the grown crystal is characterized through a CIE 1931（Commission International d＇Eclairage） color chromaticity diagram.

关键词： crystal growth optical material growth from melt photoluminescence study

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Neuroprotective role of galectin-1 in central nervous system pathophysiology

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Neural Regeneration Research 2016年第6期11卷 896-897页

作者： ravikumar Aalinkeel supriya D.Mahajan Department of Medicine Division of Allergy Immunology and Rheumatology State University of New York at Buffalo Clinical Translational Research Center

Galectins are a family of endogenousβglycan-binding proteins that play an important role in the modulation of inflammationassociated with neurodegeneration as seen in various neurological disorders such as dementia,m... 详细信息

关键词： galectin glycan neurological microglia endogenous infiltrating specifically neuronal pathology homeostasis

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