Suthindhiran K

Department of Bio-Medical Sciences

School of Bio Sciences and Technology

Vellore Campus

Jacob J.J

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Materials Science and Engineering: C

Perchlorate reducing bacteria reduce perchlorate to chlorate (ClO3−), which, in turn, is reduced to chlorite (ClO2−) and ultimately to chloride (Cl−). Magnetospirillum strains are reported to use chlorate/perchlorate as electron acceptors. This study describes the perchlorate reducing property of strain VITRJS5, a Magnetopsirillum isolated from freshwater sediment collected from Chelur freshwater lake, Kerala, India. The strain was microaerophile and was phylogenetically related to a Magnetospirillum sp., a member of the α-subclass of the class Proteobacteria. The placement of the isolate in the genus Magnetospirillum has further confirmed the presence of four key magnetosome membrane genes. PCR amplification and phylogenetic analysis of central metabolic genes such as nifH (nitrogenase) and cbbM (type II RubisCo) displayed the highest similarity (97% and 81%, respectively) with Magnetospirillum sp. BB-1 The growth kinetic parameters of the isolate were studied with acetate as the electron donor in batch experiments. Monod's substrate utilization model has been established with oxygen, nitrate and perchlorate as electron acceptors separately. The maximum specific growth rate (µmax) and half-saturation constant (ksconc) for the bacterium varied while utilizing different electron acceptors. The maximum specific growth rate was 0.226, 0.190 and 0.096 per hour and half-velocity constant Ks was 25.09, 33.36 and 65.37&nbsp;mg acetate/l for oxygen, nitrate and perchlorate, respectively. The reduction of perchlorate has been analyzed using kinetic studies of the substrate uptake by the bacteria and the half-velocity constant Ks was found to be 52.8&nbsp;mg/l. The results indicate that the strain VITRJS5 effectively reduces perchlorate by using it as an electron acceptor.

Geomicrobiology Journal

Isolation, Characterization and Kinetics of Perchlorate ReducingMagnetospirillumSpecies

In the present study, bacterial magnetosomes were used as a carrier molecule to couple with lemon grass extract (LGE) for the prevention of microbial biofilm in wound dressing material. Magnetosomes were extracted from Magnetospirillum sp. VITRJS-1 and characterised by microscopic and X-ray diffraction analysis. The phytochemical analyses of the extract showed the presence of bioactive compounds that are reported for antimicrobial and anti-inflammatory activity. Gas chromatography-mass spectrometry analysis revealed the presence of antimicrobial citral and fernesal compounds. The extract was conjugated onto the magnetosomes and confirmed by Fourier transform infrared spectroscopy analysis. The prepared magnetosome-lemon grass extract (MLGE) was evaluated for its antibiofilm property against the biofilm-forming pathogens Bacillus subtilis, Pseudomonas, Escherichia coli, Klebsiella and Staphylococcus aureus on wound dressing material by plate assay. The results indicated that the number of colonies formed was considerably reduced in MLGE coated wound dressing compared with that of LGE and control. Furthermore, SEM analysis displayed that the MLGE drastically reduced the spread of biofilm formation. Thus, MLGE coated wound dressings are effective in preventing the microbial biofilm formation, and further investigation on animal models will enable its use commercially. © The Institution of Engineering and Technology 2017.

IET Nanobiotechnology

Microbial biofilm prevention on wound dressing by nanobiocoating using magnetosomes-coupled lemon grass extract

Magnetotactic bacteria (MTB) are ubiquitous in the aquatic environment and have been identified from almost every continent; however, there are only a few reports of MTB from India. This article studies the diversity of cultivable MTB from the southern coast of India. Five strains of MTB have been identified in this study using gradient culturing; three of the five strains were isolated in pure culture. The strains iden-tified are vibrioid to helical in morphology and grow microaerophilically in oxygen-sulphide gradient me-dia. Phylogenetic analysis of isolates based on 16S rRNA gene sequences shows that they belong to the family Rhodospirillaceae, class Alphaproteobacteria, and genus Magnetospirillum. The three isolated strains were physiologically characterized and found to utilize a wide range of substrates as electron donors and electron acceptors for metabolism. The autotrophic growth of the strains was confirmed by the detection of type-II RuBisCO (cbbM) gene by PCR amplifi-cation. The presence of key magnetosome formation (mam) genes in the strains confirms the similar mechanism of magnetosome biomineralization among Magnetospirillum species. These reports of MTB from the Indian coast would contribute to the study of their evolution and biomineralization.

Current Science

Diversity of Magnetospirillum Sp. from the Southern Coast of India

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. © 2016, Springer Science+Business Media Dordrecht.

World Journal of Microbiology and Biotechnology

Isolation and characterization of Magnetospirillum from saline lagoon

<a href="https://www.sciencedirect.com/topics/materials-science/magnetite">Magnetite</a> <a href="https://www.sciencedirect.com/topics/materials-science/nanoparticles">nanoparticles</a> are becoming increasingly important for the development of novel biomedical and nanotechnology applications. What if these magnetite nanoparticles are synthesized with uniform shape, size, and dispersion? This leads to the significance of magnetosomes of magnetotactic bacteria (MTB). MTB are aquatic microorganisms that have the ability to biomineralize membrane-bound iron mineral <a href="https://www.sciencedirect.com/topics/materials-science/nanocrystals">nanocrystals</a> called magnetosomes. Magnetosomes can be easily functionalized because of the presence of various chemical groups at their surface. To explore the world of magnetosomes, it is important to understand their surface chemistry. The two major components of magnetosomes are the magnetosome membrane (MM) and magnetite mineral. MM consists of lipids and proteins. The MM lipids are divided into three major groups of fatty acids phospholipids, glycolipids, and neutral lipids. The proteins present in MM are designated as “Mam” and “mms” proteins. Magnetosome magnetite crystals have unique properties over synthetic nanoparticles such as narrow size distribution, superior shape control, high purity with limited defects, better T2 reducing effect, and chain-like alignment. The genetic manipulation of biomolecules present in the membrane and the excellent characteristics of magnetite make magnetosomes a better candidate for biomedical applications.

Journal	Data powered by TypesetMaterials Science and Engineering: C
Publisher	Data powered by TypesetElsevier BV
ISSN	0928-4931
Open Access	0