Showing papers in "Journal of the Indian Institute of Science in 2014"

Pharmaceutical Co-Crystals: A New Paradigm of Crystal Engineering

Abstract: A review on pharmaceutical co-crystals, nutraceutical co-crystals and pharmaceutical co-crystal polymorphs depicting their relevance both in academia and pharmaceutical industry because of their potential as new solid forms of the active pharmaceutical ingredient. The overview of crystal engineering to design co-crystals for altered and improved physicochemical properties such as solubility, dissolution rate, bioavailability, hygroscopicity etc., with some examples present in the literature till 2013.

Region of Interest Compressed Sensing MRI

Abstract: Compressed Sensing (CS) based Magnetic Resonance Imaging(MRI) reconstruction relies on data sparsity. Region of Interest Compressed Sensing (ROICS) is based on the hypothesis that superior CS performance can be obtained by limiting the sparsity objective and data consistency in CS to a Region of Interest (ROI). This relaxation is justified in most applications where the anatomy of interest such as the heart, has surrounding structures, typically not used for further analyses. ROICS has been proposed as an extension of CS that is ROI weighted CS. Current work demonstrates the implementation of ROICS for the first time on MR cardiac and brain data. Reconstructed images and performance evaluation metrics show that ROICS technique performs better than conventiona lCS technique. CS and Parallel Imaging (PI) are widely used to reduce MRI scan time and their combination yields better performance than used individually. The proposed method also implements the combination of ROICS and SENSitivity Encoding (SENSE), which applies weighted CSto a particular ROI, and the resulting output is then reconstructed using SENSE for arbitrary k-space. Proposed ROICS-PI performs better as comparedto PI and CS + PI.

A Brief Overview of the Recent Bio-Medical Applications of Fiber Bragg Grating Sensors

Abstract: Fiber Bragg Grating (FBG) sensors have become one of the most widely used sensors in the recent times for a variety of applications in the fields of aerospace, civil, automotive, etc. It has been recently realizedthat FBGs and etched FBGs can play an important role in bio-medical applications. This article provides a brief overview of the recent advancements in the application of FBG sensors in bio-mechanical, bio-sensing and bio-medical fields.

Human Kidney Stone Analysis using X-ray Powder Diffraction

Abstract: Physical and chemical methods available for kidney stone analysis are critically reviewed. Although various methods, such as the FTIR and Raman spectroscopy, scanning electron microscopy, thermogravimetry etc. can be used for qualitative phase analysis of kidney stones, the Rietveld method based on high quality X-ray powder diffraction data provides a precise and reliable technique for identifying the structure as well as the quantitative phase abundance of different crystalline components in human urinary calculi. Quantitative phase analyses of ten (10) kidney stones (KS1-KS10) from eastern India revealed that most of the calculi samples are mixture of phases with calcium oxalate monohydrate (whewellite) as the major constituent and varying amounts of calcium oxalate dihydrate (weddellite), calcium hydroxyapatite, uric acid and ammonium acid urate. The crystal structures of whewellite and weddellite have been redetermined using X-ray powder diffraction methodology.

Optical Fiber Sensors: A Versatile Technology Platform for Sensing

Abstract: Optical fibers are now taken for granted as signal transmission media for telecommunication and the Internet. Optical fibers also provide a versatile platform for sensing a host of physical and chemical effects, and parameters of interest. Though optical techniques for measurements were well known for a long time, utility of optical fibers for sensing and measurements has been recognised and widely appreciated only in the last twoto three decades. It has indeed become a subject of intense activity over recent times due to a variety of attractive features, notably their immunity to electromagnetic interference, enabling distributed sensing, and remote collection of sensed data for post processing owing to their compatibility to optical fiber telemetry. Fiber optics offers a versatile platform for realizing a multitude of sensors for a variety of applications in areas as broadas civilian, defence, biomedical, and so on. Functional principles of some of these sensors could be extremely simple, while some sensors couldbe ultra-sensitive that could yield extremely small magnitudes of certain measurands. This article is an attempt to review the basic principles that underpin this area of research and expose the readers to few such fiberoptical sensors by describing their applications.

Exploiting Bacterial DNA Repair Systems as Drug Targets: A Review of the Current Scenario with Focus on Mycobacteria

Abstract: Bacterial DNA repair systems as a drug target have been drawing increasing attention. Recent research has highlighted important differences between bacteria and humans in these systems. Additionally, most existing drugs are not known to act through inhibition of the components of these systems, especially involving the principal replicative ligase, and hence afford the possibility to develop new therapeutics that can overcome present problems of drug resistance. Recent work has highlighted significant differences in DNA repair systems between mycobacteria and others like E. coli, leading to the possibility of developing inhibitors that can distinguish even between these bacteria. In this review, present information on these systems from the point of view of new antibacterial development in general is collated. The subsequent focus is on mycobacterial DNA repair systems, particularly those involving DNA ligases. Presently available inhibitor scaffolds and new approaches for the development of potent inhibitors are also discussed.

Recent NMR Methodological Developments for Chiral Analysis in Isotropic Solutions

Abstract: Chiral auxiliaries are used for NMR spectroscopic study of enantiomers. Often the presence of impurities, severe overlap of peaks, excessive line broadening and complex multiplicity pattern restricts thechiral analysis using 1D 1H NMR spectrum. There are few approaches to resolve the overlapped peaks. One approach is to use suitable chiralauxiliary, which induces large chemical shift difference between the discriminated peaks (ΔδR,S) and minimize the overlap. Another directionof approach is to design appropriate NMR experiments to circumvent some of these problems, viz. enhancing spectral resolution, unravelling the superimposed spectra of enantiomers, and reduction of spectral complexity.Large number of NMR techniques, such as two dimensional selectiveF1 decoupling, RES-TOCSY, multiple quantum detection, frequency selective homodecoupling, band selective homodecoupling, broadband homodecoupling, etc. have been reported for such a purpose. Many ofthese techniques have aided in chiral analysis for molecules of diverse functionality in the presence of chiral auxiliaries. The present review summarizesthe recently reported NMR experimental methodologies, with aspecial emphasis on the work carried out in authors’ laboratory.

Molecular and Crystal Engineering Approaches Towards the Design of Functional Supramolecular Gelators

Abstract: Supramolecular gelators are an important class of compounds capable of immobilizing various solvents resulting in gels. Not much is known about the gelation mechanism and consequently, designing gelator molecule is a daunting task. However, efforts are being made to decipher the mystery of gelation and various groups are engaged in designing new gelators. Both molecular- and crystal engineering are being applied to synthesize new gelator molecules. This review article describes briefly the developments including the recent ones in this area; it also covers interesting applications offered by these wonderful materials.

Constituents of the marking-nut: 'semecarpus anacardium' linn.

Abstract: The marking-nut tree, Semecarpus anacardium Linn., occurs in the tropical outer Himalayas and in the hotter parts of India with the exception of the Eastern Peninsula. The tree itself grows to a height of 20-40 feet, with a girth of 4-6 feet and with bark 1 inch thick.

Nanomaterial based Magnetic Resonance Imaging of Cancer

Abstract: Magnetic Resonance Imaging (MRI) is a widely used non-invasive medical tool for detection and diagnosis of cancer. In recent years, MRI has witnessed significant contributions from nanotechnology to incorporate advanced features such as multimodality of nanoparticles, therapeutic delivery, specific targeting and the optical detectability for molecular imaging. Accurate composition, right scheme of surface chemistry and properly designed structure is essential for achieving desired properties of nanomaterials such as non-fouling surface, high imaging contrast, chemical stability, target specificity and/or multimodality. This review provides an overview of the recent progress in theranostic nanomaterials in imaging and the development of nanomaterial based magnetic resonance imaging of cancer. In particular, targeted theranostics is a promising approach along with its targeting strategy in cancer treatment using MRI and multimodal imaging. We also discuss recent advances in integrin mediated targeted MRI of cancer.

Advances in Image Reconstruction Methods for Real-Time Magnetic Resonance Thermometry

Abstract: Magnetic Resonance Imaging (MRI) has been widely used in cancer treatment planning, which takes the advantage of high-resolution and high-contrast provided by it. The raw data collected in the MRI can also be used to obtain the temperature maps and has been explored for performing MR thermometry. This review article describes the methods that are used in performing MR thermometry, with an emphasis on reconstruction methods that are useful to obtain these temperature maps in real timefor large region of interest. This article also proposes a prior-image constrained reconstruction method for temperature reconstruction in MRthermometry, and a systematic comparison using ex-vivo tissue experiments with state of the art reconstruction method is presented.

Silicon Waveguide Multiplexed Sensor Array Configuration for Label-Free Biosensing Applications

Abstract: This article reviews different waveguide based architectures for label-free detection of biomolecules. Working principles of various con- figurations are discussed with an emphasis on their sensing principle and sensitivity. Later part of the article demonstrates a silicon waveguide Bragg grating resonator array as a highly sensitive refractive index sen- sor device for multiplexed detection of multi-analytes. Main features of the sensor element are discussed through numerical simulation, and proof-of- concept device is demonstrated through micro fabrication. The proposed configuration of silicon waveguide based sensor array is expected to find potential application in portable chip based devices as highly sensitive multiplexed biosensors.

Civil Structural Health Monitoring Using FBG Sensors: Trends and Challenges

Abstract: Structural Health Monitoring (SHM) is a promising and challenging field of research of the 21st century. Civil structures are the most precious economic assets of any country, proper monitoring of these are necessary to prevent any hazardous situation and ensuring safety. FiberBragg Grating (FBG) sensors have emerged as a reliable, in situ, nondestructive device for monitoring, diagnostics and control in civil structures. FBG sensors offer several key advantages over other technologies in the structural sensing field. In this article, recent research and development activities in SHM using FBG sensors have been presented. Some ofthe strain-temperature discrimination techniques recently proposed by ushave also been discussed. Distributed strain sensing in a concrete bridge(field trial) using FBG sensors has been presented.

Some Themes in Chemical Crystallography Pertinent to the Indian Contribution

Abstract: It is particularly appropriate that the Journal of the Indian Institute of Science is bringing out a commemorative issue to mark the International Year of Crystallography 2014 (IYCr2014) India has had a strong crystallographic tradition, and the earliest work in what may be described as structural crystallography from this country is the work of K Banerjee on the determination of the crystal structure of naphthalene in 1930 1 The Indian Institute of Science itself has played no small part in establishing and sustaining the subject of crystallography in this country A large number of papers in this special issue are written by authors who have either have been trained in the Institute or who have some kind of professional association with this organization In this article I will try to capture some unique features that characterize the intersection of the crystallographic and the chemical domains, mostly as they pertain to the Indian contribution to this subject Crystallography is of course is as old as chemistry itself, and some would say it is even older The relationships between chemistry and crystallography go back to much before the discovery of diffraction of X-rays by crystals 2 The discovery of polymorphism by Mitscherlisch in 1822, 3 Hauy’s formulation of the molecule integrante, 4 and the work of Fedorov 5 and Groth 6 on the identification of crystals from their morphology alone, are well known examples of such relationships A very early article by Tutton speaks of “crystallo-chemical analysis” 7 In this article, I shall, however, be dealing with the interplay of chemistry and crystallography only in the post diffraction era, that is, after 1912 Much had been written and said about chemical crystallography, and even within the context of the present special issue, there is a review of chemical crystallography in India including some futuristic trends This topic was also reviewed by Nangia in a special publication brought out by Indian Academy of Sciences in 2009, 9 and by Desiraju in a special publication 10 brought out by the Indian National Science Academy in 2010 A rather detailed account of crystallography in India appeared in 2007 in the newsletter of the International Union of Crystallography (IUCr) in which chemical crystallography was detailed 11 Since all these publications are fairly recent there is little need for me to attempt a comprehensive coverage of chemical crystallography in India in this short review

Elastic Wave Sensing Using Fiber Bragg Grating-Based Sensors and Dynamic Interrogators

Abstract: Elastic Wave Sensing is a potent tool for Structural Health Monitoring (SHM) applications. In this paper, we review the use of fiber Bragg gratings (FBGs) as a viable alternative to conventional piezo electric transducers. In particular, we present Fabry-Perot filters based on fiber Bragg gratings (FP-FBG) as a possible configuration for enhanced sensitivity elastic wave sensing. Finally we discuss the directional response of FBG-based sensors, and their role in the unique identification of different Lamb modes based on their dispersion characteristics.

Macromolecular Crystallography in India in the Global Context

Abstract: The most spectacular applications of crystallography are currently concerned with biological macromolecules like proteins and their assemblies. Macromolecular crystallography originated in England in the thirties of the last century, but definitive results began to appear only around 1960. Since then macromolecular crystallography has grown to become central to modern biology. India has a long tradition in crystallography starting with the work of K. Banerjee in the thirties. In addition to their contributions to crystallography, G.N. Ramachandran and his colleagues gave a head start to India in computational biology, molecular modeling and what we now call bioinformatics. However, attempts to initiate macromolecular crystallography in India started only in the seventies. The work took off the ground after the Department of Science and Technology handsomely supported the group at Indian Institute of Science, Bangalore in 1983. The Bangalore group was also recognized as a national nucleus for the development of the area in the country. Since then macromolecular crystallography, practiced in more than 30 institutions in the country, has grown to become an important component of scientific research in India. The articles in this issue provide a flavor of activities in the area in the country. The area is still in an expanding phase and is poised to scale greater heights. *This contribution has considerable overlap with ref. 26 and ref. 27, which are based on lectures delivered by the author.

Structural and Functional Studies of Mammalian Peptidoglycan Recognition Protein, PGRP-S

Abstract: Peptidoglycan recognition proteins belong to a broad family of innate immunity molecules. Mammals have four types of peptidoglycan recognition proteins designated as PGRP-S, PGRP-Iα, PGRP-Iβ and PGRP-L. PGRP-S is expressed in the granular polymorphonuclear leucocytes, PGRP-Iα is secreted from liver into blood and PGRP-Iβ, and PGRP-L are expressed in the skin, eyes, salivary glands, throat, tongue, esophagus, stomach and intestine. Peptidoglycan recognition proteins protect the host by carrying out early recognition of invading microorganisms. They contain a common domain known as peptidoglycan recognition domain whose lengths in various PGRPs vary from 165 to 175 residues. PGRP-S consists of a single peptidoglycan recognition domain while PGRP-Iα, PGRP-Iβ and PGRP-L have additional domains. Thus, PGRP-S represents the binding component of peptidoglycan recognition proteins and for understanding the mode of binding of these proteins, structural studies of PGRP-S are essential. So far, two structures of PGRP-S, one from human and another from Camelus dromedarius are available. The structure of human PGRP-S is found to be in monomeric state while the structure of camel PGRP-S consists of two distinct dimers in which dimeric interfaces involve opposite faces of the monomer. The observed monomeric and double dimeric structures of PGRP-S are well correlated to the differences in amino acid sequences of human and camel proteins. The binding sites in the dimers of camel PGRP-S are located at the contact sites of two molecules, whereas in human PGRP-S, it is supported by the single molecule. As a result, the binding clefts in camel protein are formed more efficiently as compared to the human protein. However, tertiary structures of both camel and human proteins are almost identical, with an average root mean squares shift of 1.2 A for the backbone atoms. Since the ligand binding clefts in camel protein appear to have been evolved with better binding potencies than the human protein, the camel PGRP-S could be exploited for beneficial therapeutic applications against bacterial infections.

Comparative Structural Proteomics of Allergenic Proteins from Plant Pollen

Abstract: Major sources of allergy from plants are seeds and pollens. A large number of protein antigens have been identified to be causative agents of allergy and possible biochemical and structural attributes of these molecules have been explored. The studies so far have not been able to provide clear mechanistic details that could be generalized. The reason for this could be that the studies have not been systematically explored. The structural proteomics approaches adopted in our laboratory is an attempt in this direction to establish the structural basis of allergenicity. Known crystallographic structures of proteins from plant pollens have been analyzed in this context.

Noise Detected NMR Spectroscopy

Abstract: Spin noise phenomenon was predicted way back in 1946. However, experimental investigations regarding spin noise became possibleonly recently with major technological improvements in NMR hardware.These experiments have several potential novel applications and also demand refinements in the existing theoretical framework to explainthe phenomenon. Elegance of noise spectroscopy in gathering information about the properties of a system lies in the fact that it does not require external perturbation, and the system remains in thermal equilibrium. Spinnoise is intrinsic magnetic fluctuations, and both longitudinal and transverse components have been detected independently in many systems. Detection of fluctuating longitudinal magnetization leads to field of Magnetic Resonance Force Microscopy (MRFM) that can efficiently probe veryfew spins even down to the level of single spin utilizing ultrasensitive cantilevers.Transverse component of spin noise, which can simultaneously monitor different resonances over a given frequency range enabling oneto distinguish between different chemical environments, has also received considerable attention, and found many novel applications. These experiments demand a detailed understanding of the underlying spin noise phenomenonin order to perform perturbation-free magnetic resonance andwiden the highly promising application area. Detailed investigations ofnoise magnetization have been performed recently using force microscopyon equilibrium ensemble of paramagnetic alkali atoms. It was observed that random fluctuations generate spontaneous spin coherences whichhas similar characteristics as generated by macroscopic magnetization of polarized ensemble in terms of precession and relaxation properties. Several other intrinsic properties like g-factors, isotope-abundance ratios,hyperfine splitting, spin coherence lifetimes etc. also have been achieved without having to excite the sample. In contrast to MRFM-approaches,detection of transverse spin noise also offers novel applications, attracting considerable attention. This has unique advantage as different resonances over a given frequency range enable one to distinguish between differentchemical environments. Since these noise signatures scale inversely with sample size, these approaches lead to the possibility of non-perturbative magnetic resonance of small systems down to nano-scale. In this review,these different approaches will be highlighted with main emphasis on transverse spin noise investigations.

Chemical Crystallography in India— From Naphthalene to Gleevec

Abstract: The method of choice to determine the structure of matter at atomic resolution and at the molecular level is X-ray crystallography. Max von Laue discovered X-ray diffraction by crystals (1912) and William Henry Bragg and William Lawrence Bragg complemented the theory with the design of an X-ray spectrometer and the famous Bragg’s Law (1913). India has been an integral part of the history and development of X-ray diffraction since the work of Kedareswar Banerjee on direct methods in solving the crystal structures of naphthalene and anthrancene in the 1930s. A vertical take-off of the subject of chemical crystallography to crystal engineering happened in the last two decades. Today chemical crystallography and crystal engineering have spread horizontally into the allied fields of materials science, drug design, pharmaceutical development, nanomaterials, gas storage and solar energy devices. This account summarizes the evolution of X-ray diffraction from a fundamental technique to understanding structure–property relationships to the next challenges in studying the microstructure of crystalline solids.

High Value of Proton Relaxivity Achieved by Graphene Oxide-Cobalt Ferrite Nanoparticle Composite: A Potential Contrast Agent in Magnetic Resonance Imaging

Abstract: This work investigates the potential of graphene oxide-cobaltferrite nanoparticle (GO-CoFe2O4) composite as image contrast enhancing material in Magnetic Resonance Imaging (MRI). In the preset work, GO-CoFe2O4 composites were produced by a two-step synthesis process. In the first step, graphene oxide (GO) was synthesized, and inthe second step CoFe2O4 nano particles were synthesized in a reaction mixture containing GO to yield graphene GO-CoFe2O4 composite. Proton relaxivity value obtained from the composite was 361 mM-1s-1. This valueof proton relaxivity is higher than a majority of reported relaxivity values obtained using several ferrite based contrast agents.

Plasmonic Microstructured Optical Fibers and Their Application in Bio-Sensing

Abstract: Microstructured optical fiber embedded with metallic thin wire has been widely used for bio-sensing based on the principle of surface plasmon resonance. We review and study the fundamental properties like operating principle, design and performance of plasmonic microstructured optical fiber following photonic band gap theory. Finally, we present a very simple design of metal embedded hollow-core photonic crystal fiber for efficient sensing of very low refractive index, which can find potential application in bio-sensing.

Rigorous Design and Optimization of a New Generation of Optical Sensors

Abstract: The design and optimization of a suite of novel optical sensors is presented, showing the value of using rigorous full-vectorial numerical approaches. Although fibre based optical sensors are well established in the market, designs based on more exotic nanowires and photonic crystalfibres are becoming increasingly important and showing much improved sensitivity by accessing a larger evanescent field. Similarly, novel planar design concepts, such as the silicon slot guide-based design is showing even greater promise, allowing the exploitation of well developed CMOS fabrication technologies for potentially low-cost sensor elements. Someselected results illustrating the value and potential of the numerically efficientfinite element method in systems design are presented.

Regulation of glutamine synthetase activity

Abstract: The role ofglutamine as a donor of amino group and as a source ofnitrogen for a variety of important precursors of macromolecules is discussed. The regulation of glutamine synthetase activity in Escherichia coli occurs by repression, cumulative feedback inhibition, by divalent catir.ns, and by adenylylation and deadenylylation ofthe enzymes. The cascade consisting of the interaction, of modifying enzymes and effectors, a novel method of regulation, was discovered using this enzyme system. The regulation in the case of Gram negative organisms is achieved by synergistic inhibition by end products and by simple product inhibition.In view-of the large concentration of glutamine present in the body fluids of several mammalian organisms, the regulation of glutamine synthetase does not appear to be of major significance.Glutamine synthetase from plant sources has not been subjected to the same degree of intensive investigation. The enzymes frommung beaq (Phaseolus aureus) was purified and shown to catalyze the 6-glutamyl transferase reaction by a ping-pong mechanism. Glycine, alanine and histidine as well as adenine nucleotides inhibited in a cumulative manner. Multiple inhibition analysis revealed non exclusive binding sites for alanine and glycine and partial non-competitive and mixed type inhibition for these amino acids. Similar non-exclusivity in the binding sites for histidine and glycine were observed. ADP and AMP had mutually exclusive binding sites and were competitive inhibitors. The enzyme-antibody reaction was used to show that conformational changes occurred on the binding of substrates.A comparison of the properties of the glutamine synthetases from bacteria), animal and plant sources revealed several common features and a few significant differences emphasizing the multitude functions of glutamine in the metabolism of the cell.

Redox Proteins of Mycobacterium tuberculosis

Abstract: Evolution of life took place in a reducing atmosphere. As a reminiscence of this, cytoplasm of all living organisms is reducing in nature. Furthermore most biochemical reactions like energy production etc. are redox in nature requiring either an electron supplier or acceptor. The maintenance of redox state thus becomes extremely crucial for any cell. Cells typically devote considerable resources for the maintenance of their redox state. M. tuberculosis successfully evades an array of host generated redox stresses. For this M. tuberculosis employs a large number of redox sensors and effectors. In our laboratory we have been studying some of these central players with a hope to be able to gain insights into the pathogen. We shall try to discuss the relevance of redox and our efforts to understand the same in this review.

Diversity in Porous Metal-Organic Framework Materials

Abstract: The area of metal organic frameworks (MOF) has witnessed rapid growth over the past two decades. The successful synthesis of MOFs depends on the subtle balance between the coordination ability of the metal ion and the organic ligands. The discovery of many new MOF structures over the years suggests that this balance between the organic and the inorganic components have been achieved. The driving force for the study of MOFs, of course, is their potential use in the areas of Lewis acid catalysis, sorption, separation and storage of gases. In this article, we have attempted to highlight the important developments that have taken place during the last decade. In doing so, our focus has been to familiarize the readers with the available diversity in the structures and hence the structural aspects only have been described and discussed.

Structural Diversities in Metal-Organic Coordination Polymers Based on Flexibility in Organic Spacer

Abstract: Metal-organic coordination polymers with their various novel structural motifs have drawn intense research interests over the last few decades. Interestingly, flexibility of the organic spacers in such metalorganic coordination polymers can direct various structural topology and intricate networks. A novel 1D coordination polymer and some other illustrative examples with different flexible ligands like 1,2-bis(4-pyridyl)ethane (bpe) and 1,3-bis(4-pyridyl)propane (bpp) have been discussed in this review. Both gauche and anti-conformations could be adopted by the bpe ligand, and hence diverse structures can be furnished. Further flexibility could be achieved by exploiting longer ligand like 1,3-bis(4-pyridyl) propane (bpp). Our group has been pursuing research to furnish such flexible compounds and study their different functionalities. An account of design of such diverse systems by employing judicious ligand design strategy and their different structural aspects will be presented in this review.

Long Period Fiber Grating Based Novel Optical Fiber Devices

Abstract: Long Period Gratings (LPGs) in optical fibers have found wide applications as wavelength filters, sensors etc. This paper presents our recent work on superimposed LPG designs which show very interesting transmission characteristics. By appropriate design, these are expected to find applications as wavelength filters, sensors, channel isolation filters and wavelength interrogators. Adiabatic passage of light between twocore modes via an intermediate cladding mode without much excitation of the cladding mode is shown as an interesting application.

13C Nuclear Magnetic Resonance Investigations of Neurotransmitter Energetics in Brain

Abstract: Glutamate and GABA are the major neurotransmitters in a developed brain. Glucose is the major source of energy in the matured brain under normal physiological conditions. 13C NMR spectroscopy has been used to study neuronal glucose oxidation and neuro transmitter cyclefluxes in rats, mice and human brain. These studies indicate that neurotransmitter energetics is supported by oxidative metabolism.