Cloning and charaterisation of the Thyrotrophin-releasing hormone receptor and Gonadotrophin-relasing hormone receptor from chicken pituitary gland

The hypothalamic hormones, thyrotrophin-releasing hormone (TRH) and gonadotrophin-releasing hormone (GnRH), play pivotal roles in the growth and sexual maturation of chickens. In chickens, TRH regulates the release and synthesis of thyrotrophin (TSH) and also acts as a growth hormone-releasing factor. GnRH stimulates the release and synthesis of gonadotrophins (LH and FSH). TRH and GnRH are released and stored in the median eminence, and both hormones are transported into the pituitary gland via the hypophysial portal circulation. TRH and GnRH exert their physiological functions by binding to their specific receptors (TRH receptor and GnRH receptor, respectively) on the surface of cells in the pituitary gland. The activated receptors couple to guanine nucleotide-binding regulatory proteins (G proteins), Gq and/or G11, which in turn triggers the secondary messenger [1,2- diacylglycerol (DAG) and inositoltrisphosphate (IP3)] signalling cascade. The signalling generates the physiological effects of the hormones. The TRH-R and GnRH-R are members of G-protein coupled receptor (GPCR) family. The objective of this thesis was to clone and characterise the chicken TRH and GnRH receptors as useful tools for investigating the regulatory roles of TRH and GnRH receptors in the growth and sexual maturation of chickens. In addition, sequence information of the receptors would potentially assist in elucidating the binding sites and the molecular nature of the processes involved in receptor activation

Magneto-Optical Stern-Gerlach Effect in Atomic Ensemble

We study the birefringence of the quantized polarized light in a magneto-optically manipulated atomic ensemble as a generalized Stern-Gerlach Effect of light. To explain this engineered birefringence microscopically, we derive an effective Shr\"odinger equation for the spatial motion of two orthogonally polarized components, which behave as a spin with an effective magnetic moment leading to a Stern-Gerlach split in an nonuniform magnetic field. We show that electromagnetic induced transparency (EIT) mechanism can enhance the magneto-optical Stern-Gerlach effect of light in the presence of a control field with a transverse spatial profile and a inhomogeneous magnetic field.Comment: 7 pages, 5 figure

Conditional random fields for the prediction of signal peptide cleavage sites

Correct prediction of signal peptide cleavage sites has a significant impact on drug design. State-of-the-art approaches to cleavage site prediction typically use generative models (such as HMMs) to represent the statistics of amino acid sequences or use neural networks to detect the changes in short amino-acid segments along a query sequence. By formulating cleavage site prediction as a sequence labeling problem, this paper demonstrates how conditional random fields (CRFs) can be applied to cleavage site prediction. The paper also demonstrates how amino acid properties can be exploited and incorporated into the CRFs to boost prediction performance. Results show that the performance of CRFs is comparable to that of a state-of-the-art predictor (SignalP V3.0). Further performance improvement was observed when the decisions of SignalP and the CRF-based predictor are fused. Index Terms — Conditional random fields, discriminative models, signal peptides, cleavage sites, protein sequences

Inherent Mach-Zehnder interference with "which-way" detection for single particle scattering in one dimension

We study the coherent transport of single photon in a one-dimensional coupled-resonator-array, "non-locally" coupled to a two-level system. Since its inherent structure is a Mach-Zehnder interferometer, we explain the destructive interference phenomenon of the transmission spectrums according to the effect of which-way detection. The quantum realization of the present model is a nano-electromechanical resonator arrays with two nearest resonators coupled to a single spin via their attached magnetic tips. Its classical simulation is a waveguide of coupled defected cavity array with double couplings to a side defected cavity.Comment: 5 papges, 4 figure