Characterization of an iridovirus from the cultured pig frog Rana grylio with lethal syndrome

Three virus isolates, RGV-9506, RGV-9807 and RGV-9808, were obtained from cultured pig frogs Rana grylio undergoing lethal infections. Previously, the first isolate, RGV-9506, was shown to be an iridovirus based on ultrastructural and morphological studies. In the present study, the original isolate, along with 2 recent ones, were more extensively characterized by experimental infection studies, histopathology, electron microscopy, serological reactivity, gel electrophoresis of viral polypeptides and DNA restriction fragments, PCR amplification, and nucleic acid sequence analysis of the major capsid protein (MCP) gene. The 3 isolates were shown to be identical to each other, and very similar to FV3, the type species of the genus Ranavirus (family Iridoviridae). These results suggest that RGV should be considered a strain of FV3, and indicate that FV3-like iridoviruses are capable of causing widespread, severe disease among cultured frogs.

Purification and characterization of White Spot Syndrome Virus (WSSV) produced in an alternate host: crayfish, Cambarus clarkii

Penaeid shrimp is the natural host of White Spot Syndrome Virus (WSSV) that can cause high mortality in the infected hosts. Attempts to obtain sufficient amounts of purified intact WSSV for characterization have been unsuccessful. Using crayfish, Cambarus clarkii as a proliferation system, a large amount of infectious WSSV was reproduced and intact WSSV viral particles were purified with a new isolation medium by ultra-centrifugation. Purified WSSV particles were very sensitive to organic solvents and the detergent, Triton X-100. The size of the rod-shape, somewhat elliptical, intact WSSV was 110-130 x 260-350 mm with a long, tail-like envelope extension. The naked viral nucleocapsid was about 80 x 350 nm, and it possessed 15 spiral and cylindrical helices composed of 14 globular capsomers along its long axis, and a 'ring' structure at one terminus. Distinct WSSV genome DNA patterns were obtained when the purified genomic dsDNA of WSSV was digested with five different restriction enzymes (HindIII, XhoI, B(BamHI, SalI, and SacI). In addition, at least 13 major and distinct protein bands could be observed when purified intact WSSV viruses were separated by SDS-PAGE followed by Coomassie Brilliant R-250 staining. The estimated molecular weights of these proteins were 190, 84, 75, 69, 68, 58, 52, 44, 28, 27.5, 23, 19, and 16 kD, respectively. Both the 44 and 190 kD proteins were easily removed if the hemolymph from the: WSSV infected crayfish was transiently treated with 1%, Triton X-100 before it was subjected to gradient centrifugation, indicating that both of them are located on the surface of the viral envelope. These characteristics are consistent with WSSV isolated from the penaeid shrimp. (C) 2001 Elsevier Science B.V. All rights reserved.

High efficiency operation of butt joint line-defect-waveguide microlaser in two-dimensional photonic crystal slab

Butt joint line-defect-waveguide microlasers are demonstrated on photonic crystal slabs with airholes in a triangular lattice. Such microlaser is designed to increase the output power from the waveguide edge directly. The output power is remarkably enhanced to 214 times higher by introducing chirped structure in the output waveguide. The lasing mode operates in the linear dispersion region of the output waveguide so that the absorption loss due to the band-edge effect is reduced. The laser resonance is illustrated theoretically using the finite difference time domain method. A practical high power efficiency of 20% is obtained in this microlaser. (C) 2008 American Institute of Physics.

A novel butt-joint scheme for the preparation of electro-absorptive lasers

A 1.55 mu m InGaAsP/InGaAsP multiple-quantum-well electro-absorption modulator (EAM) monolithically integrated with a distributed feedback laser (DFB) diode has been realized based on a novel butt-joint scheme by ultra-low metal-organic vapour phase epitaxy for the first time. The threshold current of 25 mA and an extinction ratio of more than 30 dB are obtained by using the novel structure. The beam divergence angles at the horizontal and vertical directions are as small as 19.3 degrees x 13 degrees, respectively, without a spot-size converter by undercutting the InGaAsP active region. The capacitance of the ridge waveguide device with a deep mesa buried by polyimide was reduced down to 0.30 pF.

Butt-Joint Monolithicaily Integrated DFB-LD/EA-MD Light Source for 10Gbit/s Transmission

This paper reports on the design, fabrication, and performance of an integrated electro-absorptive modulated laser based on butt-joint configuration for 10Gbit/s application. This paper mainly aims at two aspects. One is to improve the optical coupling between the laser and modulator; another is to increase the bandwidth of such devices by reducing the capacitance parameter of the modulator. The integrated devices exhibit high static and dynamic characteristics. Typical threshold current is 15mA,with some value as low as 8mA. Output power at 100mA is more than 10mW. The extinction characteristics,modulation bandwidth, and electrical return loss are measured. 3dB bandwidth more than 10GHz is monitored.

Integrated electroabsorption-modulated DFB laser by using an improved butt-joint method

An improved butt coupling method is used to fabricate an electroabsorption modulator (EAM) monolithically integrated with a distributed feedback (DFB) laser. The obtained electroabsorption-modulated laser (EML) chip with the traditional shallow ridge exhibits very low threshold current of 12 mA, output power of more than 8 mW, and static extinction ratio of -7 dB at the applied bias voltage from 0.5 to -2.0 V.

Improved digital processing method used for image motion measurement based on hybrid opto-digital joint transform correlator

Hybrid opto-digital joint transform correlator (HODJTC) is effective for image motion measurement, but it is different from the traditional joint transform correlator because it only has one optical transform and the joint power spectrum is directly input into a digital processing unit to compute the image shift. The local cross-correlation image can be directly obtained by adopting a local Fourier transform operator. After the pixel-level location of cross-correlation peak is initially obtained, the up-sampling technique is introduced to relocate the peak in even higher accuracy. With signal-to-noise ratio >= 20 dB, up-sampling factor k >= 10 and the maximum image shift <= 60 pixels, the root-mean-square error of motion measurement accuracy can be controlled below 0.05 pixels.

Influence of Hypericum perforatum Extract on Piglet Infected with Porcine Respiratory and Reproductive Syndrome Virus

To study the influence of Hypericum perforatum extract (HPE) on piglets infected with porcine respiratory and reproductive syndrome virus (PRRSV), enzyme-labeled immunosorbent assay (ELISA) and cytopathic effect (CPE) were used to determine in vitro whether HPE could induce swine pulmonary alveolar macrophages (PAMs) to secrete IFN-gamma, and whether PRRSV titers in PAMs were affected by the levels of HPE-induced IFN-gamma. HPE (200 mg kg(-1)) was administrated by oral gavage to piglets infected with the PRRSV in vivo to observe whether HPE affected the viremia, lung viral titers, and weight gain of piglets infected with PRRSV. The results showed that HPE was capable of inducing PAMs to produce IFN-gamma in a dose dependent manner and HPE pretreatment was capable of significantly reducing PRRSV viral titers in PAMs (P<0.01). Administration of HPE to the PRRSV-infected animals significantly (P<0.05) reduced viremia over time as compared with the PRRSV-infected animals. But there was not significant decrease in lung viral titers at day 21 post-infection between the HPE-treated animals and the PRRSV-infected control piglets. There were no significant differences in weight gain over time among the HPE-treatment animals, the normal control, and the HPE control animals. The PRRSV-infected animals caused significant (P<0.01) growth retardation as compared with the HPE controls and the normal piglets. It suggested that HPE might be an effective novel therapeutic approach to diminish the PRRSV-induced disease in swine.

Capillary electrophoresis coupled with electrochemiluminescence detection using porous etched joint

A new setup to couple capillary electrophoresis (CE) with electrochemiluminescence (ECL) detection is described in which the electrical connection of CE is achieved through a porous section at a distance of 7 mm from the CE capillary outlet. Because the porous capillary wall allowed the CE current to pass through and there was no electric field gradient beyond that section, the influence of CE high-voltage field on the ECL procedure was eliminated. The porous section formed by etching the capillary with hydrofluoric acid after only one side of the circumference of 2-3 mm of polyimide coating of the capillary was removed, while keeping the polyimide coating on the other part to protect the capillary from HF etching makes the capillary joint much more robust since only a part of the circumference of it is etched. A standard three-electrode configuration was used in experiments with Pt wire as a counter electrode, Ag/AgCl as a reference electrode, and a 300-mum diameter Pt disk as a working electrode. Compared with CE-ECL conventional decoupler designs, the present setup with a porous joint has no added dead volume created.

Short-capillary electrophoresis with electrochemiluminescence detection using porous etched joint for fast analysis of lidocaine and ofloxacin

Fast analysis of ofloxacin and lidocaine, as bactericide and analgesic or anesthetics, is of clinic importance for understanding the patient's medical process. This paper presented a high throughput, simple analysis method of lidocaine and ofloxacin by capillary electrophoresis coupled with electrochemiluminescence (ECL) using porous etched joint. To shorten the analysis time and to improve the analytical performance, a capillary with 10 cm in length was used as the separation channel. The cyclic voltammograms of Ru(bpy)(3)(2+) with different capillary length at same field strength showed that the porous etched joint eliminated the effect of electrophoretic current on the ECL detection. Following micro total analysis systems (muTAS), some advantages of which this approach has, the fabrication of channel in chip was not needed. Compared with capillary electrophoresis with 40-cm-long capillary, the high sample throughput and low zone broadening may be the main advantage of the present system. Under optimal condition, the detection limits of lidocaine and ofloxacin based on peak height were 3.0 x 10(-8) and 5.0 x 10(-7) mot L-1 and a 60 h(-1) of sampling frequency was obtained.