Molecular characterization of known and novel olfactory subsystems in the zebrafish

Olfaction or the sense of smell is phylogenetically ancient, and mediates many vital behaviors such as prey detection, predator evasion, reproduction and kin recognition. Basic principles of vertebrate olfaction, among them the so-called -'one neuron-one receptor' rule and the principle of axonal convergence, are conserved in zebrafish, a powerful vertebrate model system. Furthermore, zebrafish possess orthologs of all but one of the six olfactory receptor families described for mammals, and both main olfactory sensory neuron types, ciliated and microvillous neurons, are present in zebrafish, together with the corresponding signal transduction cascades. Here I show that the principle of axonal convergence of same-receptor-expressing neurons is valid for crypt neurons, a poorly understood third type of olfactory neurons that expresses the V1R-related ORA4 as sole olfactory receptor. I could identify the crypt neuron target glomerulus as mdg2, one of six invariant glomeruli in the mediodorsal cluster of the olfactory bulb.Together with the expression of ORA4 in all crypt neurons, this finding reveals a novel coding strategy in vertebrate olfaction: 'one cell type – one target glomerulus'. In the course of these studies I discovered and characterized a novel, forth population of olfactory neurons, which we named kappe neurons for their cap-like apical protrusion. For another member of the ora gene family, the recently deorphanized ORA1 receptor, I have identified a putative biological function for the first time. I could show that low concentrations of para-hydroxyphenyl acetic acid, a high affinity ligand of ORA1, elicit increases in oviposition frequency in zebrafish mating pairs, raising the exciting possibility that para-hydroxyphenyl acetic acid might constitute a novel reproductive pheromone. Whether the activation of a single olfactory receptor is sufficient to generate behavioral output, is currently an active field of research. However there are very few cases described, where this has been shown to be the case, chief among them the insect pheromone receptors. I could show that low concentrations of cadaverine, a high affinity ligand for a zebrafish trace amine-associated receptor, TAAR13c, are sufficient to elicit a distinct avoidance behavior, and that at the same low concentration most of the activated olfactory neurons expressed TAAR13c, using pERK levels as measure of neuronal activation. This result suggests that TAAR13c is the major and conceivably the only receptor eliciting sensitive avoidance behavior to cadaverine

Bloodmeal Hydrolysate In Novatein Thermoplastic Protein

Novatein Thermoplastic (NTP) is a bloodmeal based plastic developed by the University of Waikato by mixing bloodmeal with water, additives and tri-ethylene glycol (TEG - a plasticiser and petroleum based product) so it can be extruded and injection moulded. The aim of this research was to produce a bloodmeal hydrolysate that could be used in NTP as a substitute for TEG, and also used to treat sodium bentonite clay to improve its properties as a filler in NTP. Bloodmeal was hydrolysed with pepsin and alcalase to determine the reaction rate, degree of hydrolysis and optimum conditions. Bloodmeal could be readily hydrolysed giving up to 80% hydrolysis yield with 25-40% degree of hydrolysis, with average peptide molecular weight ranging between 2-12 kDa for alcalase, and 20-25% degree of hydrolysis and average molecular weights of 20-80 kDa for pepsin. Large scale hydrolysis with alcalase, trypsin and then pepsin gave 80% hydrolysis yield, and peptide average molecular weights at 8.9 kDa for alcalase, to 5.5 for trypsin. Adsorption of hydrolysate on to sodium bentonite gave 127 mg/g clay adsorption for alcalase, but was low for trypsin, and no adsorption occurred for pepsin hydrolysate. Specific mechanical energy required to extrude NTP increased with increasing hydrolysate content but only slightly increased with clay content, but in both cases increased with extent of hydrolysis, i.e. trypsin hydrolysate gave greater SME than alcalase, and pepsin hydrolysate gave greater SME than trypsin, which could be due to the increasing salt content in the hydrolysate. Tensile strength, secant modulus, crystallinity, thermostability and glass transition temperature decreased with increasing hydrolysate content in NTP, likely due to the shorter average protein chain length, indicative of some plasticisation. Glass transition temperature did not change for NTP with alcalase hydrolysate. Toughness, strain at break, and impact strength were low indicating a very brittle material. Highly variable results were obtained for the NTP with treated and untreated clay as a filler, but generally gave lower mechanical properties than conventional NTP. Alcalase treated clay was particularly detrimental on NTP composite strain at break and toughness. Thermostability of the composites increased within the 450-600oC region with increasing clay concentration for all treated clays, but showed a much more rapid decrease in mass loss

Antioxidant and Skeletal Muscle Relaxant Activity of Leaf Extract of Plant Piper Attenuatum (B. HAM)

Piper attenuatum (B. Ham) is traditional medicinal plant in India. It has been claimed in traditional Indian system of medicine that the phytochemical constituents present in P. attenuatum (B. Ham) have Antioxidant and skeletal muscle relaxant activity. So the present study aimed to evaluate anti–oxidant and skeletal muscle relaxant activity of ethanolic, aqueous and ethanolic leaf extract of plant P. attenuatum (B. Ham), respectively. Antioxidant activity was evaluated by in vitro as well as in vivo methods. Invitro method we used DPPH (2, 2-diphenyl-1-picrylhydrazyl) free radical scavenging assay and H2O2 (Hydrogen Peroxide) scavenging assay while in vivo methods antioxidant enzymes like Superoxide Dismutase (SOD) and reduced glutathione (GSH) were assayed by using animal models. Anti-oxidant activity of following concentrations 10μg/mL, 20μg/mL, 30μg/mL, 40μg/mL and 50μg/mL were measured for both extracts. Ethanolic extract of P. attenuatum (B. Ham) was evaluated at dose of 100mg/kg and 200 mg/kg b.w. for skeletal muscle relaxant activity by using rota rod apparatus. The high antioxidant activity was found in the ethanolic extract of P. attenuatum (B. Ham) compared to aqueous one. For muscle relaxation, 200 mg/kg b.w. showed a significant reduction in the time spent by the animals on the revolving rod compared to the control. From the above study it may be concluded that both extract of P. attenuatum (B. Ham) having Anti – oxidant and skeletal muscle relaxant activity

Complexity of Scheduling in Synthesizing Hardware from Concurrent Action Oriented Specifications

Concurrent Action Oriented Specifications (CAOS) formalism such as Bluespec Inc.\u27s Bluespec System Verilog (BSV) has been recently shown to be effective for hardware modeling and synthesis. This formalism offers the benefits of automatic handling of concurrency issues in highly concurrent system descriptions, and the associated synthesis algorithms have been shown to produce efficient hardware comparable to those generated from hand-written Verilog/VHDL. These benefits which are inherent in such a synthesis process also aid in faster architectural exploration. This is because CAOS allows a high-level description (above RTL) of a design in terms of atomic transactions, where each transaction corresponds to a collection of operations. Optimal scheduling of such actions in CAOS-based synthesis process is crucial in order to generate hardware that is efficient in terms of area, latency and power. In this paper, we analyze the complexity of the scheduling problems associated with CAOS-based synthesis and discuss several heuristics for meeting the peak power goals of designs generated from CAOS. We also discuss approximability of these problems as appropriate

Elimination of a ligand gating site generates a supersensitive olfactory receptor

Olfaction poses one of the most complex ligand-receptor matching problems in biology due to the unparalleled multitude of odor molecules facing a large number of cognate olfactory receptors. We have recently deorphanized an olfactory receptor, TAAR13c, as a specific receptor for the death-associated odor cadaverine. Here we have modeled the cadaverine/TAAR13c interaction, exchanged predicted binding residues by site-directed mutagenesis, and measured the activity of the mutant receptors. Unexpectedly we observed a binding site for cadaverine at the external surface of the receptor, in addition to an internal binding site, whose mutation resulted in complete loss of activity. In stark contrast, elimination of the external binding site generated supersensitive receptors. Modeling suggests this site to act as a gate, limiting access of the ligand to the internal binding site and thereby downregulating the affinity of the native receptor. This constitutes a novel mechanism to fine-tune physiological sensitivity to socially relevant odors

Recent smell loss is the best predictor of COVID-19 among individuals with recent respiratory symptoms

In a preregistered, cross-sectional study we investigated whether olfactory loss is a reliable predictor of COVID-19 using a crowdsourced questionnaire in 23 languages to assess symptoms in individuals self-reporting recent respiratory illness. We quantified changes in chemosensory abilities during the course of the respiratory illness using 0-100 visual analog scales (VAS) for participants reporting a positive (C19+; n=4148) or negative (C19-; n=546) COVID-19 laboratory test outcome. Logistic regression models identified univariate and multivariate predictors of COVID-19 status and post-COVID-19 olfactory recovery. Both C19+ and C19- groups exhibited smell loss, but it was significantly larger in C19+ participants (mean±SD, C19+: -82.5±27.2 points; C19-: -59.8±37.7). Smell loss during illness was the best predictor of COVID-19 in both univariate and multivariate models (ROC AUC=0.72). Additional variables provide negligible model improvement. VAS ratings of smell loss were more predictive than binary chemosensory yes/no-questions or other cardinal symptoms (e.g., fever). Olfactory recovery within 40 days of respiratory symptom onset was reported for ~50% of participants and was best predicted by time since respiratory symptom onset. We find that quantified smell loss is the best predictor of COVID-19 amongst those with symptoms of respiratory illness. To aid clinicians and contact tracers in identifying individuals with a high likelihood of having COVID-19, we propose a novel 0-10 scale to screen for recent olfactory loss, the ODoR-19. We find that numeric ratings ≤2 indicate high odds of symptomatic COVID-19 (4<10). Once independently validated, this tool could be deployed when viral lab tests are impractical or unavailable

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Application of a Sandwich Construction on a Superstructure of a High Speed Ferry

Usage of light weight materials has gained momentum in the marine market in the last few decades. This rise has lead to some ships using parts fabricated out of materials like glass and carbon fibre. A major advantage of the usage of light weight materials in shipping is that it either increases the cargo carrying capacity of the vessel or reduces the fuel consumption or both. Different kinds of problems and issues need to be addressed when using new and innovative materials. These problems range from issues of both technical and non-technical nature. Technical problems are generally related to structural strength, fire safety and joining materials of different kinds. Non-technical issues would include maintenance and most importantly getting a good idea about the economics and pay back time of using light weight materials.This thesis discusses the possibility of using light weight materials like glass and carbon fibre as a super structure on board the 88 m long Stena Carisma catamaran. Sandwich construction is the recommended method of employing light weight construction. Different concepts have been generated using the spacing of pillars and the materials used. Analytical structural analysis for each concept is performed. The concept that has the lightest weight is further evaluated using the finite element (FE) method. Thus both analytical calculations and FE analyses have been used to confirm the feasibility of having a sandwich superstructure for the vessel. Both static and dynamic analysis are conducted for the study of the superstructure. Classification society regulations are used as the base to do the structural calculations. Considering the various criteria of the society, a structural optimisation is also performed. Based on the results obtained from the analysis performed, it is shown that a conventional aluminium superstructure for such a vessel can be replaced by innovative light weight materials. This replacement would be accompanied by a reduction in the weight of the vessel as well as by reduced maintenance requirement. Thus there is a two fold benefit from application of light weight materials. This work includes the structural analysis of the superstructure made of composite materials and also about the interaction of the two materials namely aluminium and the composites. FE analysis has been done to understand the structural behaviour of the structure. This analysis is carried out in ANSYS

Sandwich Construction - Application on a superstructure

The use of light weight materials is increasing at a rapid pace in the present day industry. Automobiles, aircrafts, ships and several other fields are increasingly finding large potential in using lighter materials for construction. In the past few years a number of water borne means of transportation have been moulded from composites. For ships, this leads to reducing the light weight and thus an increase in the capacity of the payload. A reduction in the light weight of the ship implies more cargo and more revenue generation for the ship owner. Over an average lifetime of 25 years, the amount of revenue generated could be significant, due to which a number of ship owners are giving a serious thought to the usage of light weight materials in shipping. Stena Line, a Swedish shipping company has a number of passenger ferries running in the European region. They are also the proud owners of the HSS series of ships, which are unique as they are catamarans made completely in aluminium. Being the pioneers in the shipping industry, they have considered the possibility of having a sandwich superstructure for one of their ferries, HSS 900. This paper looks into the preliminary design of the structure under DNV regulations. While fire safety is also part of the project, this paper focuses on the structure. Different kinds of fibres, resins and cores could be used for making the sandwich construction. The fibre making the faces could be E-glass, S-glass, carbon fibre etc, the resin systems also provide a variety of options like the polyesters, vinyl esters and phenolics. Similarly the core material could be honeycomb, PVC or PU. In this paper, possibilities of using these materials for the making the superstructure has been looked into. A preliminary calculation shows how much in terms of light weight of the vessel could be saved if sandwich construction is used. As it is weight critical approach that is the driving factor in using light weight materials, an optimization of the structure by breaking it up into sandwich panel, spacing of the transverses and longitudinal has also been performed. While optimizing the sandwich panel, four major criteria of maximum normal stress, maximum shear stress, wrinkling stress and maximum allowed deflection have been explored. The limit point where all the four requirements are met and the weight is minimum possible has been considered as the optimum point. All in all it is a sandwich superstructure, which has been optimized for weight