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T. Revathy

Bio: T. Revathy is an academic researcher from VIT University. The author has contributed to research in topics: Magnetosome & Magnetotactic bacteria. The author has an hindex of 5, co-authored 10 publications receiving 92 citations.

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Journal ArticleDOI
28 Oct 2015
TL;DR: The results indicate that the isolated Burkholderia sp.
Abstract: The polycyclic aromatic hydrocarbons (PAHs) pollution to the environment is a major threat to the living organisms, and hence the degradation of these PAHs is necessary. Studies on PAHs degrading bacteria have focussed on terrestrial microbes and the potential of marine derived microbes is undermined. Herein we report the isolation and characterization of PAHs degrading Burkholderia sp. from lagoon sediments collected at the Southern coast of India. The strain was Gram negative, rod-shaped, motile, and ∼2–5 μm in length. Based on the phylogenetic data the strain was identified as Burkholderia and designated as VITRSB1. Initial PAHs degradation ability of the strain was assessed using basal salt medium supplemented with diesel, kerosene, toluene, aniline, naphthalene, and phenol. The strain was found to be effectively degrading kerosene, diesel, toluene, and aniline even at higher concentration (1%). However, naphthalene and aniline were degraded only at lower concentration (0.1%) and phenol, camphor, and DAP inhibited the growth of the strain. Furthermore, the degraded end products of the PAHs were determined using FTIR. Notably, none of the end products were found to be toxic to the biosphere. Our results indicate that the isolated Burkholderia sp. could be a prospective candidate for the effective degradation of selective PAHs.

29 citations

Journal ArticleDOI
TL;DR: This is the first report of antimicrobial, antioxidant and enzyme inhibitory activities of these three plant extracts and suggests that phytosteroids are present in all the three plants.
Abstract: Araucaria cookii, Bauhinia blakeana and Brassaia actinophylla are ornamental plants. The presence of various phytochemicals and pharmacologically important compounds in these plants can be exploited for their medicinal use. But there are no reports on the phytochemical and pharmacological evaluation of these plants and this study aims at investigating these. The plant extracts were prepared in different solvents like methanol, ethanol, ethyl acetate, acetone, hexane, water and chloroform. Qualitative analysis of phytochemicals were assessed. The anti-microbial, anti-oxidant and enzyme inhibitory activity was determined for all three plant extracts. Anti-bacterial activity against three gram negative bacteria, E. coli, Pseudomonas and Klebsiella was done and Araucaria cooki showed highest antibacterial activity among the three plants. Maximum antioxidant activity was seen in methanol extract of Brassaia actinophyla with 81% inhibition. The order of the antioxidant activity of the three plants are in the order B.actinophylla>A cookie>B.blakeana. The results of phytochemical analysis suggest that phytosteroids are present in all the three plants. Maximum inhibition against the tested enzymes was exhibited by hexane and chloroform extracts of A.cookii. Hemolytic activity was done and the hexane extract showed maximum haemolysis where as aqueous extracts showed minimum activity. From the results it is clear that the three plant extracts has pharmacological applications. This is the first report of antimicrobial, antioxidant and enzyme inhibitory activities of these three plant extracts. Further studies are needed to exploit the actual mechanism and active compounds of these plants.

24 citations

Journal ArticleDOI
01 Jun 2017
TL;DR: The results suggest that the magnetosomes are safe at lower concentration and does not pose any potential risk to the ecosystem.
Abstract: Magnetosomes are nanosized iron oxide particles surrounded by lipid membrane synthesized by magnetotactic bacteria (MTB). Magnetosomes have been exploited for a broad range of biomedical and biotechnological applications. Due to their enormous potential in the biomedical field, its safety assessment is necessary. Detailed research on the toxicity of the magnetosomes was not studied so far. This study focuses on the toxicity assessment of magnetosomes in various models such as Human RBC’s, WBC’s, mouse macrophage cell line (J774), Onion root tip and fish (Oreochromis mossambicus). The toxicity in RBC models revealed that the RBC’s are unaltered up to a concentration of 150 µg/ml, and its morphology was not affected. The genotoxicity studies on WBC’s showed that there were no detectable chromosomal aberrations up to a concentration of 100 µg/ml. Similarly, there were no detectable morphological changes observed on the magnetosome-treated J774 cells, and the viability of the cells was above 90% at all the tested concentrations. Furthermore, the magnetosomes are not toxic to the fish (O. mossambicus), as no mortality or behavioural changes were observed in the magnetosome-treated groups. Histopathological analysis of the same reveals no damage in the muscle and gill sections. Overall, the results suggest that the magnetosomes are safe at lower concentration and does not pose any potential risk to the ecosystem.

16 citations

Journal ArticleDOI
TL;DR: From the results it is evident that the ethyl acetate extract of Streptomyces sp.
Abstract: Marine actinomycetes are potential source for the d iscovery of novel compounds and enzymes. Though extensive research on marine actinomycetes is under way globally, the actinomycetes research from India n marine ecosystem is unexplored and understudied. Hence, the present research is focussed on the screen ing of bioactive compounds from marine actinomycetes isolated from Indian coastal region. This study is designed to determine the antioxidant and enzyme inhibitory potential of Streptomyces sp. VITMSS05 strain, isolated from Marakkanam, southern coast of India. An actinomycetes strain designated as VITMSS05 was isolated. This strain was cultivated i n Starch Caesin Agar medium (SCA) supplemented with sea water. The cultural, morphological and mol ecular characterization was determined for the isolate. The crude extract of the isolate was extra cted with ethyl acetate. Antioxidant activity of th e crude extract was determined by DPPH radical scavenging assay. Alpha amylase and alpha glucosidase inhibitory potential of the extract was determined. Based on the phenotypic and phylogenetic analysis the strain was identified as Streptomyces sp. Significant antioxidant activity of the extract was observed with an IC50 value of 92.49 �g mL -1 . The extract shows 64.1% inhibition on α-amylase and 91.5% inhibition on α-glucosidase at 100 �g mL -1 with an IC50 value of 385.97 and 42.89 �g mL -1 . From the results it is evident that the ethyl aceta te extract of Streptomyces sp. VITMSS05 has potent antioxidant and enzyme inhibitory activity in vitro . The combined effect of free radical scavenging an d enzyme inhibition makes it a potent anti diabetic d rug.

15 citations

Journal ArticleDOI
TL;DR: The results indicate that the systematic procedure using sediment analysis, CARD–FISH, and a combination of isolation methods enables the selective and rapid isolation of MTB from aquatic sediment sample.
Abstract: Magnetotactic bacteria (MTB) are aquatic prokaryotes that orient themselves to earth's magnetic field with the help of intracellular organelle magnetosomes. Although many species of MTB have been identified, the isolation of MTB is a challenging task due to the lack of systematic isolation procedure and/or commercial media. In this study, we are reporting the isolation of magnetotactic spirillum from the Pulicat lagoon, India using a systematic and selective procedure. Sampling site was chosen on the basis of physicochemical properties of the ecosystem and the catalysed reporter deposition fluorescence in situ hybridization (CARD-FISH) analysis of sediment samples. In the current study, a combination of techniques including 'capillary racetrack' Purification and gradient cultivation resulted in the isolation of magnetotactic spirilla from aquatic sediments. Based on the 16S rRNA gene sequence analysis, the strain was identified as Magnetospirillum and was designated as Magnetospirillum sp. VITRJS1. The genes responsible for magnetosome formation (mamA, B, E, F, K, M, O, P, Q, T) were successfully detected using PCR amplification. The presence of cbbM gene confirmed that the isolate is chemolithoautotroph and utilises reduced sulphur as an electron source. Furthermore, magnetosomes extracted from VITRJS1 found to be cubo-octahedral in shape and 45 nm in size. Our results indicate that the systematic procedure using sediment analysis, CARD-FISH, and a combination of isolation methods enables the selective and rapid isolation of MTB from aquatic sediment sample.

13 citations


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Journal ArticleDOI
01 Sep 1945-Nature
TL;DR: This text-book of pharmacognosy has grown from a laboratory manual intended for use in practical classes, and now comprises the requirements for the Chemist and Druggist Qualifying Examination of the Pharmaceutical Society of Great Britain.
Abstract: THIS text-book of pharmacognosy has already found wide recognition among teachers and students of pharmacy. Its subject matter has grown from a laboratory manual intended for use in practical classes, and now comprises the requirements for the Chemist and Druggist Qualifying Examination of the Pharmaceutical Society of Great Britain. A Textbook of Pharmacognosy By T. C. Denston. Fourth edition. Pp. xviii + 594. (London: Sir Isaac Pitman and Sons, Ltd., 1945.) 27s. 6d. net.

701 citations

Journal ArticleDOI
TL;DR: This study has comprehensively described phylogenetic and functional compositions of these habitats and inferred a multitude of metagenomic features including 255 taxa and 414 functional modules which can be used as biomarkers for effective distinction between the 12 oil polluted sites.
Abstract: Microbial remediation of oil polluted habitats remains one of the foremost methods for restoration of petroleum hydrocarbon contaminated environments. The development of effective bioremediation strategies however, require an extensive understanding of the resident microbiome of these habitats. Recent developments such as high-throughput sequencing has greatly facilitated the advancement of microbial ecological studies in oil polluted habitats. However, effective interpretation of biological characteristics from these large datasets remain a considerable challenge. In this study, we have implemented recently developed bioinformatic tools for analyzing 65 16S rRNA datasets from 12 diverse hydrocarbon polluted habitats to decipher metagenomic characteristics of the resident bacterial communities. Using metagenomes predicted from 16S rRNA gene sequences through PICRUSt, we have comprehensively described phylogenetic and functional compositions of these habitats and additionally inferred a multitude of metagenomic features including 255 taxa and 414 functional modules which can be used as biomarkers for effective distinction between the 12 oil polluted sites. Additionally, we show that significantly over-represented taxa often contribute to either or both, hydrocarbon degradation and additional important functions. Our findings reveal significant differences between hydrocarbon contaminated sites and establishes the importance of endemic factors in addition to petroleum hydrocarbons as driving factors for sculpting hydrocarbon contaminated bacteriomes.

107 citations

Journal ArticleDOI
TL;DR: Toxicity evaluation is a critical point in the development of nanoformulations and therefore, draws considerable attention and might be evaluated further for safety related issues considering future medications based on MNPs.

82 citations

Journal ArticleDOI
TL;DR: The ability of MTB to biomineralize the magnetic particles (magnetosomes) into uniform nano-sized, highly crystalline structure with uniform magnetic properties has made the bacteria an important topic of research.

74 citations