Highly efficient detector of the neurotransmitter ACh and AChE inhibitors

Among the variety of applications for biosensors one of the exciting frontiers is to utilize those devices as post-synaptic sensing elements in chemical coupling between neurons and solid-state systems. The first necessary step to attain this challenge is to realize highly efficient detector for neurotransmitter acetylcholine (ACh). Herein, we demonstrate that the combination of floating gate configuration of ion-sensitive field effect transistor (ISFET) together with diluted covalent anchoring of enzyme acetylcholinesterase (AChE) onto device sensing area reveals a remarkable improvement of a four orders of magnitude in dose response to ACh. This high range sensitivity in addition to the benefits of peculiar microelectronic design show, that the presented hybrid provides a competent platform for assembly of artificial chemical synapse junction. Furthermore, our system exhibits clear response to eserine, a competitive inhibitor of AChE, and therefore it can be implemented as an effective sensor of pharmacological reagents, organophosphates, and nerve gases as well. © 2007 Materials Research Society.

On chip plasmonic enhanced silicon schottky detector for telecom wavelengths

We demonstrate an integrated on-chip plasmonic enhanced Schottky detector for telecom wavelengths based on the internal photoemission process. This CMOS compatible device may serve as a promising alternative to the Si-Ge detectors. © 2011 Optical Society of America.

Bead-probe complex capture a couple of SINE and LINE family from genomes of two closely related species of East Asian cyprinid directly using magnetic separation

Background: Short and long interspersed elements (SINEs and LINEs, respectively), two types of retroposons, are active in shaping the architecture of genomes and powerful tools for studies of phylogeny and population biology. Here we developed special protocol to apply biotin-streptavidin bead system into isolation of interspersed repeated sequences rapidly and efficiently, in which SINEs and LINEs were captured directly from digested genomic DNA by hybridization to bead-probe complex in solution instead of traditional strategy including genomic library construction and screening. Results: A new couple of SINEs and LINEs that shared an almost identical 3'tail was isolated and characterized in silver carp and bighead carp of two closely related species. These SINEs (34 members), designated HAmo SINE family, were little divergent in sequence and flanked by obvious TSD indicated that HAmo SINE was very young family. The copy numbers of this family was estimated to 2 x 10(5) and 1.7 x 10(5) per haploid genome by Real-Time qPCR, respectively. The LINEs, identified as the homologs of LINE2 in other fishes, had a conserved primary sequence and secondary structures of the 3'tail region that was almost identical to that of HAmo SINE. These evidences suggest that HAmo SINEs are active and amplified recently utilizing the enzymatic machinery for retroposition of HAmoL2 through the recognition of higher-order structures of the conserved 42-tail region. We analyzed the possible structures of HAmo SINE that lead to successful amplification in genome and then deduced that HAmo SINE, SmaI SINE and FokI SINE that were similar in sequence each other, were probably generated independently and created by LINE family within the same lineage of a LINE phylogeny in the genomes of different hosts. Conclusion: The presented results show the advantage of the novel method for retroposons isolation and a pair of young SINE family and its partner LINE family in two carp fishes, which strengthened the hypotheses containing the slippage model for initiation of reverse transcription, retropositional parasitism of SINEs on LINEs, the formation of the stem loop structure in 3'tail region of some SINEs and LINEs and the mechanism of template switching in generating new SINE family.

Silicon-metal waveguide as a high efficiency schottky detector for telecom wavelengths

We demonstrate an integrated on-chip compact and high efficiency Schottky detector for telecom wavelengths based on silicon metal waveguide. Detection is based on the internal photoemission process. Theory and experimental results are discussed. © 2012 Optical Society of America.

Establishment of a Chinese sturgeon Acipenser sinensis tail-fin cell line and its susceptibility to frog iridovirus

Chinese sturgeon Acipenser sinensis, a cartilaginous ganoid, is a 'living fossil' on a deeply isolated evolutionary branch. A cell line was established from Chinese sturgeon tail-fin tissue (CSTF) . These epithelial CSTF cells grew well in Dulbecco's modified Eagle's medium at 25 degrees C. Karyotypic analysis revealed a normal diploid karyotype with 2n = 264 and large numbers of punctate chromosomes. A strain of frog iridoviruses [Rana grylio virus (RGV)] was used to test the susceptibility of this cell line to infection. Infection was confirmed by cytopathic effect, immunofluorescence and electron-microscope observations, which detected the viral antigens or particles in the cytoplasm of RGV-infected cells. Molecular analysis further suggested that c. 550 bp DNA fragment could be cloned from the RGV-infected CSTF cells' DNA with major capsid protein gene polymerase chain reaction primers. Furthermore, after transfection with pEGFP vector DNA, the CSTF cell line produced significant fluorescent signals indicating its utility in exogenous studies.

Chirp-enhanced direct modulation of a monolithic sub-Terahertz dual laser transmitter

A technique enabling 10 Gbps data to be directly modulated onto a monolithic sub-THz dual laser transmitter is proposed. As a result of the laser chirp, the logical zeros of the resultant sub-THz signal have a different peak frequency from that of the logical ones. The signal extinction ratio is therefore enhanced by suppressing the logical zeros with a filter stage at the receiver. With the aid of the chirp-enhanced filtering, an improved extinction ratio can be achieved at moderate modulation current. Hence, 10 GHz modulation bandwidth of the transmitter is predicted without the need for external modulators. In this paper, we demonstrate the operational principle by generating an error-free (bit error rate less than 10-9) 100 Mbps Manchester encoded signal with a centre frequency of 12 GHz within the bandwidth of an envelope detector, whilst direct modulation of a 100 GHz signal at data rates of up to 10 Gbps is simulated by using a transmission line model. This work could be a key technique for enabling monolithic sub-THz transmitters to be readily used in high speed wireless links. © 2013 IEEE.

Isolation, characterization and genome sequence of a birnavirus strain from flounder Paralichthys olivaceus in China

A birnavirus strain, Paralichthys olivaceus birnavirus (POBV), was isolated and characterized from cultured flounder in China, and its complete genomic sequence was subsequently determined. The virus could induce cytopathic effects (CPE) in four of seven fish cell lines and was resistant to chloroform, 5-iodo-2'-deoxyuridine, acid and alkaline pH, and heat treatment. Purified virus particles had a typical icosahedral shape, with a diameter of approximately 55-60 nm. The genomic segments A and B of POBV were 3,091 and 2,780 bp in length and shared many of the features of the members of the family Birnaviridae. Segment A contained two partially overlapping ORFs encoding a polyprotein, pVP2-VP4-VP3, and a nonstructural protein, VP5, while segment B had only one ORF encoding for the VP1, a viral RNA-dependent RNA polymerase (RdRp). This is the first report about a birnavirus strain from a new non-salmonid host in China and its complete genome sequence.

Locally-oxidized silicon surface-plasmon Schottky detector for telecom wavelengths

We demonstrate an integrated on-chip locally-oxidized silicon surface-plasmon Schottky detector for telecom wavelengths based on the internal photoemission process. Theoretical model and experimental results will be presented and discussed. © 2011 Optical Society of America.

Establishment, characterization, and virus susceptibility of a new marine cell line from red spotted grouper (Epinephelus akaara)

A marine fish cell line from the snout of red spotted grouper Epinephelus akaara, a protogynous hermaphrodite, was established, characterized, and subcultured with more than 60 passages. The grouper snout cell line (GSC) cells multiplied well in Dulbecco's modified Eagle's medium (DMEM) medium supplemented with 10% fetal bovine serum. The optimal growth temperature was 25 degrees C, and morphologically the cells were fibroblastic. Chromosome analysis revealed that the GSC cell line has a normal diploid karyotype with 2n = 8st + 40t. A virus titration study indicated that the cells were susceptible to turbot Scophthalmus Maximus rhabdovirus (SMRV) (10(8.5) TCID50 ml(-1)), while the viral titer of frog Rana grylio virus 9807 (RGV(9807)) reached 10(3.5) TCID50 ml-1. The infection was confirmed by cytopathic effect (CPE), immunofluorescence, and electron microscopy experiments, which detected the viral particles in the cytoplasm of virus-infected cells, respectively. Further, significant fluorescent signals were observed when the GSC cells were transfected with pEGFP vector DNA, indicating their potential utility for transgenic and genetic manipulation studies.

Theoretical study of line narrowing in a sub-terahertz monolithic dual laser source with an integrated reflector

A monolithic design is proposed for low-noise sub-THz signal generation by integrating a reflector onto a dual laser source. The reflectivity and the position of such a reflector can be adjusted to obtain constructive feedback from the reflector to both lasers, thus causing a Vernier feedback effect. As a result, 10-fold line narrowing, the narrowing being limited by the resolution of the simulation, is predicted using a transmission line model. Finally, a simple control scheme using an electrical feedback loop to adjust laser biases is proposed to maintain the line narrowing performance. This line narrowing technique, comprising a passive integrated reflector, could allow the development of a low-cost, compact and energy-efficient solution for high-purity sub-THz signal generation. © The Institution of Engineering and Technology 2014.

Effects of brominated flame retardants and brominated dioxins on steroidogenesis in H295R human adrenocortical carcinoma cell line

Brominated flame retardants (BFRs) and brominated dioxins are emerging persistent organic pollutants that are ubiquitous in the environment and can be accumulated by wildlife and humans. These chemicals can disturb endocrine function. Recent studies have demonstrated that one of the mechanisms of endocrine disruption by chemicals is modulation of steroidogenic gene expression or enzyme activities. In this study, an in vitro assay based on the H295R human adrenocortical carcinoma cell line, which possesses most key genes or enzymes involved in steroidogenesis, was used to examine the effects of five bromophenols, two polybrominated biphenyls (PBBs 77 and 169), 2,3,7,8-tetrabromodibenzo-p-dioxin, and 2,3,7,8-tetrabromodibenzofuran on the expression of 10 key steroidogenic genes. The H295R cells were exposed to various BFR concentrations for 48 h, and the expression of specific genescytochrome P450 (CYP11A, CYP11B2, CYP17, CYP19, and CYP21), 3 beta-hydroxysteroid dehydrogenase (3PHSD2), 17 beta-hydroxysteroid dehydrogenase (17 beta HSD1 and 17 beta HSD4), steroidogenic acute regulatory protein (StAR), and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR)-was quantitatively measured using real-time polymerase chain reaction. Cell viability was not affected at the doses tested. Most of the genes were either up- or down-regulated, to some extent, by BFR exposure. Among the genes tested, 3PHSD2 was the most markedly up-regulated, with a range of magnitude from 1.6- to 20-fold. The results demonstrate that bromophenol, bromobiphenyls, and bromodibenzo-p-dioxin/furan are able to modulate steroidogenic gene expression, which may lead to endocrine disruption.

Electron microscopic examination of the viromatrix of Rana grylio virus in a fish cell line

Rana grylio virus (RGV), a Ranavirus belonging to the family Iridoviridae, assembles in the viromatrix which is a factory for viral genome replication and particle assembly. Ultrastructural studies of the viromatrix will clarify the pathway of assembly. The viromatrix and quantitative changes in RGV infected epithelipma papulosum cyprini (EPC) cells, one of fish cell lines, were studied by electron microscopy. It was shown that viromatrices were adjacent to the nucleus, and the electron density was lower than that of the surrounding cytoplasm. The viromatrix contained virus particles with different forms, electron-dense materials and amorphous structures which included tubules and membranous materials. Tubules were often observed in direct continuity with empty capsids. Several bundles of intermediate filaments were seen alongside the viromatrix and crystalline aggregates. Large clusters of mitochondria occurred in proximity to viromatrix. A total of 990 cells profiles were examined. The results showed that 394 cells contained viromatrix: 89.3% contained one, and 10.7% contained two to four viromatrices. The number of viromatrices increased gradually and reached a peak at 16 h p.i. The viromatrix area at 24 h p.i. increased up to 7.4 +/- 0.69 mu m(2) which was three-times lower than that at 6 h p.i. The number of empty capsids within viromatrix was generally more than that of "full" particles at different time points, and there was a strong positive correlation between them. (c) 2005 Elsevier B.V. All rights reserved.

Inductive expression and characterization analysis of Paralichthys olivaceus pigment epithelium-derived factor in a virally infected cell line

Pigment epithelium-derived factor (PEDF) is acknowledged to be a non-inhibitory member of the serine protease inhibitor (serpin) superfamily, with antiangiogenesis, and neuroprotective and immumoregulatory function, mainly in the tissues of nervous system. Here, A PEDF gene homolog, Paralichthys olivaceus PEDF (PoPEDF), was isolated from flounder embryonic cells (FEC) treated with UV-inactivated Grass carp hemorrhage virus (GCHV) and subsequently identified as a differentially expressed gene. The full length of PoPEDF cDNA is 1803 bp with an open reading frame of 1212 bp encoding a 403-amino-acid protein. This deduced protein contains an N-terminal signal peptide, a glycosylation site, a consensus serpin motif, and a 34-mer and a 44-mer fragment, all of which are very conserved in the PEDF family. PoPEDF gene exhibits a conserved exon-intron arrangement with 8 exons and 7 introns. This conserved evolutionary relationship was further confirmed by a phylogenetic analysis, where fish PEDFs and mammalian members formed a well-supported clade. Constitutive expression of PoPEDF was widely detected in many tissues. In response to UV-inactivated GCHV or poly(I:C), PEDF mRNA was upregulated in FEC cells with time. This is the first report on the transcriptional induction of PEDF in virally infected cells. (C) 2005 Elsevier Inc. All rights reserved.

Establishment of a normal medakafish spermatogonial cell line capable of sperm production in vitro

Spermatogonia are the male germ stem cells that continuously produce sperm for the next generation. Spermatogenesis is a complicated process that proceeds through mitotic phase of stem cell renewal and differentiation, meiotic phase, and postmeiotic phase of spermiogenesis. Full recapitulation of spermatogenesis in vitro has been impossible, as generation of normal spermatogonial stem cell lines without immortalization and production of motile sperm from these cells after long-term culture have not been achieved. Here we report the derivation of a normal spermatogonial cell line from a mature medakafish testis without immortalization. After 140 passages during 2 years of culture, this cell line retains stable but growth factor-dependent proliferation, a diploid karyotype, and the phenotype and gene expression pattern of spermatogonial stem cells. Furthermore, we show that this cell line can undergo meiosis and spermiogenesis to generate motile sperm. Therefore, the ability of continuous proliferation and sperm production in culture is an intrinsic property of medaka spermatogonial stem cells, and immortalization apparently is not necessary to derive male germ cell cultures. Our findings and cell line will offer a unique opportunity to study and recapitulate spermatogenesis in vitro and to develop approaches for germ-line transmission.

Induction of apoptosis in a carp leucocyte cell line infected with turbot (Scophthalmus maximus L.) rhabdovirus

A rhabdovirus was observed from the diseased turbot (Scophthalmus maximus L.) with lethal syndrome. In this study, a carp leucocyte (CLC) cell line was used to investigate the infection process and cell death mechanism occurring during the virus infection. Strong cytopathogenic effect (CPE) and the morphological changes, such as extreme chromatin condensation, nucleus fragmentation, and apoptotic body formation, were observed under fluorescence microscopy after DAPI staining in the infected CLC cells. Transmission electron microscopy analysis showed cell shrinkage, plasma membrane blebbing, cytoplasm vacuolization, chromatin condensation, nuclear breakdown and formation of discrete apoptotic bodies. The bullet-shaped nucleocapsids were measured and ranged in size from 110 to 150 nm in length and 40 to 60 nm in diameter. And therefore the virus is called Scophthalmus maximus rhabdovirus (SMRV). Agarose gel electrophoresis analysis of the DNA extracted from infected cells showed typical DNA ladder in the course of SMRV infection. Flow cytometry analysis of SMRV infected CLC cells detected apoptotic peak in the virus infected CLC cells. Virus titre analysis and electron microscopic observation revealed that the virus replication fastigium was earlier than that of the apoptosis occurrence. No apoptosis was observed in the CLC infected with UV-inactivated SMRV. All these supported that SMRV infected CLC cells undergo apoptosis and the virus replication is necessary for apoptosis induction of CLC cells. (C) 2004 Published by Elsevier B.V.