Two-photon calcium imaging from head-fixed Drosophila during optomotor walking behavior.

Drosophila melanogaster is a model organism rich in genetic tools to manipulate and identify neural circuits involved in specific behaviors. Here we present a technique for two-photon calcium imaging in the central brain of head-fixed Drosophila walking on an air-supported ball. The ball's motion is tracked at high resolution and can be treated as a proxy for the fly's own movements.

Role of dimer interface in activation and desensitization in AMPA receptors.

The conversion of chemical to electrical signals by the AMPA receptors is the key step by which these proteins control cognitive and motor responses. Here, we have used luminescence resonance energy transfer (LRET) to gain insight into the conformational changes induced by glutamate binding in the agonist-binding domain in functional AMPA receptors expressed in oocytes and HEK-293 cells. The LRET-based distances indicate that the interface between the upper lobes of the agonist-binding domain within a dimer is in a decoupled state in the unligated Apo state of the receptor.

Subunit arrangement in N-methyl-D-aspartate (NMDA) receptors.

N-Methyl-d-aspartate (NMDA) receptors, the main mediators of excitatory synaptic transmission, are heterotetrameric receptors. Typically, glycine binding NR1 subunits co-assemble with glutamate binding NR2 subunits to form a functional receptor. Here we have used luminescence resonance energy transfer (LRET) investigations to establish the specific configuration in which these subunits assemble to form the functional tetramer and show that the dimer of dimers structure is formed by the NR1 subunits assembling diagonally to each other.

CAMP: a useful resource for research on antimicrobial peptides.

Antimicrobial peptides (AMPs) are gaining popularity as better substitute to antibiotics. These peptides are shown to be active against several bacteria, fungi, viruses, protozoa and cancerous cells. Understanding the role of primary structure of AMPs in their specificity and activity is essential for their rational design as drugs.

Imaging neural activity in worms, flies and mice with improved GCaMP calcium indicators.

Genetically encoded calcium indicators (GECIs) can be used to image activity in defined neuronal populations. However, current GECIs produce inferior signals compared to synthetic indicators and recording electrodes, precluding detection of low firing rates. We developed a single-wavelength GCaMP2-based GECI (GCaMP3), with increased baseline fluorescence (3-fold), increased dynamic range (3-fold) and higher affinity for calcium (1.

Vibrational spectroscopic investigation of the ligand binding domain of kainate receptors.

Fourier transform infrared spectroscopy has been used to probe the agonist-protein interactions in the ligand binding domain of the GluR6 subunit, one subunit of the kainate subtype of glutamate receptors. In order to study the changes in the interactions over a range of activations the investigations were performed using the wild type, N690S, and T661E mutations. These studies show that the strength of the interactions at the alpha-amine group of the agonist, as probed by studying the environment of the nondisulphide bonded Cys 432, acts as a switch with weaker interactions at lower activations and stronger interactions at higher activations.

Feature selection and classification employing hybrid ant colony optimization/random forest methodology.

Accurate classification of instances depends on identification and removal of redundant features. Classification of data having high dimensionality is usually performed in conjunction with an appropriate feature selection method. Feature selection enables identification of the most informative feature subset from the enormously vast search space that can accurately classify the given data.

Review on lazy learning regressors and their applications in QSAR.

Building accurate quantitative structure-activity relationships (QSAR) is important in drug design, environmental modeling, toxicology, and chemical property prediction. QSAR methods can be utilized to solve mainly two types of problems viz., pattern recognition, (or classification) where output is discrete (i.

Low decorin expression along with inherent activation of ERK1,2 in ear lobe keloids.

Over production of collagen and its abnormal assembly is the hallmark of abnormal scars such as keloids, a condition which reflects fibrosis of the skin. Fibrotic conditions of organs such as liver, lungs and eyes are characterized by low levels of decorin, a member of the small leucine proteoglycan family, which is an indispensable modulator of collagen assembly. Involvement of decorin in keloids is not well described, therefore, its expression in keloids was studied here.

Evaluating a genetically encoded optical sensor of neural activity using electrophysiology in intact adult fruit flies.

Genetically encoded optical indicators hold the promise of enabling non-invasive monitoring of activity in identified neurons in behaving organisms. However, the interpretation of images of brain activity produced using such sensors is not straightforward. Several recent studies of sensory coding used G-CaMP 1.

LRET investigations of conformational changes in the ligand binding domain of a functional AMPA receptor.

The structural investigations using the soluble ligand binding domain of the AMPA subtype of the glutamate receptor have provided invaluable insight into the mechanistic pathway by which agonist binding to this extracellular domain mediates the formation of cation-selective channels in this protein. These structures, however, are in the absence of the transmembrane segments, the primary functional component of the protein. Here, we have used a modified luminescence resonance energy transfer based method to obtain distance changes due to agonist binding in the ligand binding domain in the presence of the transmembrane segments.

Overexpression and functional characterization of the extracellular domain of the human alpha1 glycine receptor.

A novel truncated form (residues 1-214, with a randomized C-terminal tail) of the ligand-binding extracellular domain (ECD) of the human alpha1 glycine receptor (GlyR), with amino acids from the corresponding sequence of an acetylcholine binding protein (AChBP) substituted for two relatively hydrophobic membrane-proximal loops, was overexpressed using a baculovirus expression system. The mutant GlyR ECD, named GlyBP, was present in both soluble and membrane-associated fractions after cell lysis, though only the latter appeared to be in a native-like conformation capable of binding strychnine, a GlyR specific antagonist. The membrane-associated GlyBP was solubilized, and detergent/lipid/protein micelles were affinity purified.

Luminescence resonance energy transfer investigation of conformational changes in the ligand binding domain of a kainate receptor.

The apo state structure of the isolated ligand binding domain of the GluR6 subunit and the conformational changes induced by agonist binding to this protein have been investigated by luminescence resonance energy transfer (LRET) measurements. The LRET-based distances show that agonist binding induces cleft closure, and the extent of cleft closure is proportional to the extent of activation over a wide range of activations, thus establishing that the cleft closure conformational change is one of the mechanisms by which the agonist mediates receptor activation. The LRET distances also provide insight into the apo state structure, for which there is currently no crystal structure available.

Declining semen quality among south Indian infertile men: A retrospective study.

Background: Male reproductive function has recently attracted increasing attention due to reports on time-related decline in semen quality. Furthermore, regional differences in the semen quality have also been reported.

Aim: To investigate the semen quality among large cohort of infertile individuals at a regional level, in terms of the sperm concentration, total sperm motility, sperm morphology and incidence of azoospermia over a period of 13 years.

Chemical interplay in the mechanism of partial agonist activation in alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors.

Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, one subtype in the family of ionotropic glutamate receptors, are the main receptors responsible for excitatory signaling in the mammalian central nervous system. Previous studies utilitizing the isolated ligand binding domain of these receptors have provided insight into the role of specific ligand-protein interactions in mediating receptor activation. However, these studies relied heavily on the partial agonist kainate, in which the alpha-amine group is constrained in a pyrrolidine ring.

Nadi Tarangini: a pulse based diagnostic system.

Ayurveda is a traditional medicine and natural healing system in India. Nadi-Nidan (pulse-based diagnosis) is a prominent method in Ayurveda, and is known to dictate all the salient features of a human body. In this paper, we provide details of our procedure for obtaining the complete spectrum of the nadi pulses as a time series.

Arterial pulse system: modern methods for traditional Indian medicine.

Ayurveda is one of the most comprehensive healing systems in the world and has classified the body system according to the theory of Tridosha to overcome ailments. Diagnosis similar to the traditional pulse-based method requires a system of clean input signals, and extensive experiments for obtaining classification features. In this paper we briefly describe our system of generating pulse waveforms and use various feature detecting methods to show that an arterial pulse contains typical physiological properties.

Using recurrence quantification analysis descriptors for protein sequence classification with support vector machines.

In this work, we integrate a non-linear signal analysis method, recurrence quantification analysis (RQA), with the well-known machine-learning algorithm, support vector machines for the binary classification of protein sequences. Two different classification problems were selected, discriminating between aggregating and non-aggregating proteins and mostly disordered and completely ordered proteins, respectively. It has also been shown that classification performance of SVM models improve on selection of the most informative RQA descriptors as SVM input features.

Glutamate receptors as seen by light: spectroscopic studies of structure-function relationships.

Ionotropic glutamate receptors are major excitatory receptors in the central nervous system and also have a far reaching influence in other areas of the body. Their modular nature has allowed for the isolation of the ligand-binding domain and for subsequent structural studies using a variety of spectroscopic techniques. This review will discuss the role of specific ligand:protein interactions in mediating activation in the a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid subtype of glutamate receptors as established by various spectroscopic investigations of the GluR2 and GluR4 subunits of this receptor.

Facially disfigured children--dedicated approach and rehabilitation.

Facial disfigurement following congenital anomalies or acquired defects due to accidents or scars results in mental trauma and other related consequences. A multidisciplinary team approach with special importance to rehabilitation is required in handling such patients.

Water soluble RNA based antagonist of AMPA receptors.

Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors are one of the important receptor classes involved in glutamate-mediated excitotoxicity. Although small molecule antagonists of this receptor have been shown to have neuroprotective properties, their low solubilities pose severe side effects in clinical trials. Here we have used the SELEX method to obtain water-soluble nuclease-resistant RNA ligands that bind to the agonist binding site of AMPA receptors.

Effects of Anterior-Posterior Constraint on Injury Patterns in the Human Knee During Tibial-Femoral Joint Loading from Axial Forces through the Tibia.

According to the National Accident Sampling System (NASS), 10% of all automobile accident injuries involve the knee. These injuries involve bone fracture and/or "soft tissue" injury. Previous investigators have determined the tibial-femoral (TF) joint failure load for an experimentally constrained human knee at 90 degrees flexion.

The effect of loading rate on the degree of acute injury and chronic conditions in the knee after blunt impact.

accidents are often overlooked, but can have a profound societal cost. Knee injuries, for example, account for approximately 10% of the total injuries. Fracture of the knee is not only an acute issue but may also have chronic, or long term, consequences.

Role of the chemical interactions of the agonist in controlling alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor activation.

Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors are the main excitatory neurotransmitter receptors in the mammalian central nervous system. Structures of the isolated ligand binding domain of this receptor have provided significant insight into the large-scale conformational changes, which when propagated to the channel segments leads to receptor activation. However, to establish the role of specific molecular interactions in controlling fine details such as the magnitude of the functional response, we have used a multiscale approach, where changes at specific moieties of the agonists have been studied by vibrational spectroscopy, while large-scale conformational changes have been studied using fluorescence resonance energy transfer (FRET) investigations.