Comparative proteome and peptidome analysis of the cephalic fluid secreted by Arapaima gigas (Teleostei: Osteoglossidae) during and outside parental care

Parental investment in Arapaima gigas includes nest building and guarding, followed by a care provision when a cephalic fluid is released from the parents’ head to the offspring. This fluid has presumably important functions for the offspring but so far its composition has not been characterised. In this study the proteome and peptidome of the cephalic secretion was studied in parental and non-parental fish using capillary electrophoresis coupled to mass spectrometry (CE-MS) and GeLC-MS/MS analyses. Multiple comparisons revealed 28 peptides were significantly different between males and parental males (PC-males), 126 between females and parental females (PC-females), 51 between males and females and 9 between PC-males and PC-females. Identification revealed peptides were produced in the inner ear (pcdh15b), eyes (tetraspanin and ppp2r3a), central nervous system (otud4, ribeye a, tjp1b and syn1) among others. A total of 422 proteins were also identified and gene ontology analysis revealed 28 secreted extracellular proteins. From these, 2 hormones (prolactin and stanniocalcin) and 12 proteins associated to immunological processes (serotransferrin, α-1-antitrypsin homolog, apolipoprotein A-I, and others) were identified. This study provides novel biochemical data on the lateral line fluid which will enable future hypotheses-driven experiments to better understand the physiological roles of the lateral line in chemical communication

Protein immobilization onto electrochemically synthesized CoFe nanowires

Sri Ramulu Torati,1 Venu Reddy,1 Seok Soo Yoon,2 CheolGi Kim1 1Department of Emerging Materials Science, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea; 2Department of Physics, Andong National University, Andong, South Korea Abstract: CoFe nanowires have been synthesized by the electrodeposition technique into the pores of a polycarbonate membrane with a nominal pore diameter of 50 nm, and the composition of CoFe nanowires varying by changing the source concentration of iron. The synthesized nanowire surfaces were functionalized with amine groups by treatment with aminopropyltriethoxysilane (APTES) linker, and then conjugated with streptavidin-Cy3 protein via ethyl (dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide coupling chemistry. The oxide surface of CoFe nanowire is easily modified with aminopropyltriethoxysilane to form an amine terminating group, which is covalently bonded to streptavidin-Cy3 protein. The physicochemical properties of the nanowires were analyzed through different characterization techniques such as scanning electron microscope, energy dispersive spectroscopy, and vibrating sample magnetometer. Fluorescence microscopic studies and Fourier transform infrared studies confirmed the immobilization of protein on the nanowire surface. In addition, the transmission electron microscope analysis reveals the thin protein layer which is around 12–15 nm on the nanowire surfaces. Keywords: electrodeposition, biofunctionalization, streptavidi

Micromagnet Conductors for High-Resolution Separation of Magnetically Driven Beads and Cells at Multiple Frequencies

We demonstrate a separation method for complex mixture of superparamagnetic beads using half-disk pathways, under an in-plane rotating magnetic field, which is highly sensitive to the bead size and magnetic susceptibility. The non-linear dynamics of the beads moving along the half-disk pathways at multiple frequencies can be divided into three regimes: a phase-locked regime at low driving frequencies, a phase-slipping regime above the first critical frequency fc1, and a phase-insulated regime above the second critical frequency fc2 in which the beads just hop at the gaps between two half-disks. Hence, based on the dynamical motions, the beads with varied sizes or heterogenic magnetic properties can be separated efficiently. Furthermore, a bio-selective separation of bead plus human monocytic leukemia (THP-1) cell complexes from bare beads has been achieved due to the increased drag force on the complexes, resulting in a decreased critical frequency. © 2010-2012 IEEE.