Involvement of aurantiactinomyxon in the life cycle of Thelohanellus testudineus (Cnidaria: Myxosporea) from allogynogenetic gibel carp Carassius auratus gibelio, with morphological, ultrastructural, and molecular analysis.

During the investigation of actinosporean fauna diversity from commercial fish ponds in Hubei Province, China, a novel aurantiactinomyxon type was found from Branchiura sowerbyi. Spore body of the aurantiactinomyxon was ellipsoidal in side view and triangular in apical view, 15.5 ± 0.5 (14.5-16.4) µm in diameter; three leaf-like caudal processes were approximately equal, measuring 13.2 ± 0.9 (11.5-16.2) µm long and 7.4 ± 0.4 (6.7-8.0) µm wide at the base; three polar capsules were located at the apex of spore body, globular in apical view, 2.2 ± 0.1 (2.0-2.3) µm in diameter, and pyriform in side view, 2.5 ± 0.2 (2.3-2.9) µm in length and 2.0 ± 0.2 (1.8-2.4) µm in width; a total of 32 germ cells were observed within the sporoplasm. Ultrastructural analysis showed that the development was asynchronous between pansporocysts but synchronous within a pansporocyst. The formation of sporoblast and the development of sporogonic stage were also described and discussed. The 18S ribosomal DNA sequences of the current aurantiactinomyxon type corresponded to that of a previously reported Thelohanellus testudineus, suggesting that the newly identified aurantiactinomyxon type is the actinosporean stage in the life cycle of T. testudineus.

Proliferation and resistance difference of a liver-parasitized myxosporean in two different gynogenetic clones of gibel carp.

Some myxosporeans have been demonstrated to be harmful to worldwide aquaculture. However, the proliferation information has remained unclear in the fish hosts. In this study, we utilized the mix-culturing equality to reveal significant difference in disease assistance between two different clones of gibel carp, in which clone D had been cultured for nearly 40 years, whereas clone A(+) was a newly created clone. According to morphological and genetic analysis of isolated spores, the diseasing pathogen was identified as Myxobolus wulii of the genus Myxobolus in Myxosporea. Subsequently, a polyclonal antibody specific to soluble proteins of the purified spores was generated. Using the antibody, we performed immunofluorescence observation of the liver lump sections sampled from the heavily diseased clone D individuals, and found that the liver lumps were completely composed of numerous honeycomb-like cysts, full of maturing and mature myxosporean spores, and almost all of liver tissues were destroyed. Comparative co-localization detection revealed a significantly inducing expression of apo-14 protein around the infected myxosporean sporoplasms and plasmodia, and the inducing level was much stronger in clone A(+) than in clone D. Furthermore, a primarily screening of 15 different major histocompatibility complex class Iα variants also excavated major variants that respectively belong to clones D and A(+). Therefore, these data provide significant information for differences in myxosporean proliferation and disease resistance in fish clone hosts with different genetic background. Further studies on myxosporean development and the mechanism for disease resistance will be very important for preventing and controlling the parasitic myxosporean disease.

Both Myosin-10 isoforms are required for radial neuronal migration in the developing cerebral cortex.

During embryonic development of the mammalian cerebral cortex, postmitotic cortical neurons migrate radially from the ventricular zone to the cortical plate. Proper migration involves the correct orientation of migrating neurons and the transition from a multipolar to a mature bipolar morphology. Herein, we report that the 2 isoforms of Myosin-10 (Myo10) play distinct roles in the regulation of radial migration in the mouse cortex. We show that the full-length Myo10 (fMyo10) isoform is located in deeper layers of the cortex and is involved in establishing proper migration orientation. We also demonstrate that fMyo10-dependent orientation of radial migration is mediated at least in part by the netrin-1 receptor deleted in colorectal cancer. Moreover, we show that the headless Myo10 (hMyo10) isoform is required for the transition from multipolar to bipolar morphologies in the intermediate zone. Our study reveals divergent functions for the 2 Myo10 isoforms in controlling both the direction of migration and neuronal morphogenesis during radial cortical neuronal migration.

Identification and characterization of one novel type of Triactinospomyxon with short spore axis.

This study identifies and characterizes one novel type of triactinospomyxon in oligochaete specimen of Branchiura sowerbyi Beddard collected from a fish pond used for rearing gibel carp located in Caidian Experimental Station of the Institute of Hydrobiology. It is nominated as Triactinospomyxon caidianensis type. The spore is of characteristic triactinomyxon "anchor" shape and possesses a spore body with sporoplasm containing 32 germ cells, 3 polar capsules, and 3 caudal processes. Compared with other triactinomyxon spores described previously, T. caidianensis type has a short spore axis with 76.5 µm in length and a very short style with 38.9 µm in length. Molecular analyses on 18S rDNA sequences indicate that the novel T. caidianensis type is most closely related to Triactinomyxon sp SA-2005, Antonactinomyxon sp KAB-2001, and Synactinomyxon sp KAB-2001 with 80.33% to 81.92% identities. On the basis of spore morphology and genetic data, the T. caidianensis type presented in this paper differs from those already known and described in the literatures.

Multimodal coherent anti-Stokes Raman spectroscopic imaging with a fiber optical parametric oscillator.

We report on multimodal coherent anti-Stokes Raman scattering (CARS) imaging with a source composed of a femtosecond fiber laser and a photonic crystal fiber (PCF)-based optical parametric oscillator (FOPO). By switching between two PCFs with different zero dispersion wavelengths, a tunable signal beam from the FOPO covering the range from 840 to 930 nm was produced. By combining the femtosecond fiber laser and the FOPO output, simultaneous CARS imaging of a myelin sheath and two-photon excitation fluorescence imaging of a labeled axons in rat spinal cord have been demonstrated at the speed of 20 µs per pixel.

Expression pattern of cellular nucleic acid-binding protein (CNBP) during embryogenesis and spermatogenesis of gibel carp.

By differential screening, we cloned the CagCNBP, demonstrated its predominant expression in ovary and testis, and reported its development behavior during folliculogenesis and oogenesis by immunofluorescence localization (Liu and Gui, Gene 365:181-192, 2005), but its developmental behavior during spermatogenesis and its transcript distribution during embryogenesis are not revealed. In the present study, by in situ hybridization, we analyze CagCNBP expression pattern during gibel carp embryogenesis. The CagCNBP transcripts ubiquitously distributed in all embryonic cells in early developmental stage embryos, and peak in midbrain, hindbrain and somites of gibel carp larva during organogenesis. By antibody detection, we reveal CagCNBP protein distribution change during spermatogenesis. The cell-specific distribution of CagCNBP is revealed by immunofluorescence staining, and predominant CagCNBP expression in testis somatic cells and spermatogonia is demonstrated in this paper. For the first time, the CNBP distribution during spermatogenesis in vertebrate has been revealed.

Molecular characterization and expression pattern of AFPIV during embryogenesis in gibel carp(Carassiu auratus gibelio).

As a new type of AFPs, AFPIV has been firstly identified in longhorn sculpin (Myoxocephalus octodecimspinosus), and in recent years, its cDNA and amino acid sequence have been reported, and its pancreatic synthesis has been firstly reported in polar fish. However, its expression patterns during fish embryogenesis have not been elucidated yet. By differential screening, we cloned the CagAFPIV in gibel carp, Carassius auratus gibelio, demonstrated its predominant expression during embryogenesis. RT-PCR detection revealed that CagAFPIV was first transcribed from blastula stage and kept a high level during embryogenesis and declined remarkably in hatched larva. In situ hybridization revealed that CagAFPIV transcripts were firstly distributed over the margin and marginal blastomere in blastula stage embryos, at the early-gastrula stage the positive signals distributed in the marginal cells and the internalization cells, and later restricted to the cells the yolk syncytial layer (YSL) from later gastrula stage to larva stage. Consistently, the CagAFPIV protein also kept a high level during embryogenesis, and the high protein level retained some days after the larva hatched. Our work, for the first time, revealed the dynamic expression and distribution of CagAFPIV during embryogenesis.

Molecular characterization and expression pattern of fetuin-B in gibel carp (Carassius auratus gibelio).

Fetuin-B has recently been cloned and identified from rats, mice, and humans; their expression patterns, however, have not been elucidated yet. In this study, Cagfetuin-B has been cloned in gibel carp. RT-PCR and Western blot detection revealed that Cagfetuin-B is first transcribed from the blastula stage and at a relatively stable level afterward during embryogenesis and the larval stage. Cagfetuin-B transcripts are predominantly distributed over the yolk syncytial layer in the early embryos and later restricted to the cells of liver and brain in newly hatched larvae. Moreover, a dynamic distribution of Cagfetuin-B protein was observed in brain, kidney, liver, and skin during morphogenesis. In adult fish, Cagfetuin-B transcripts are restricted in liver and ovary. Our work, for the first time, revealed the extra-hepatic transcription and a dynamic distribution of fetuin-B during embryogenesis and in adults, which indicates the potential roles of fetuin-B in fish organogenesis.

Absolute self-calibration of the quantum efficiency of single-photon detectors.

Single-photon detectors are finding increasingly wide application in all branches of science and technology thus a precise knowledge of their quantum efficiency is an essential prerequisite. We have performed the first proof-of-principle demonstration of a means to determine the quantum efficiency by which no second detector or reference standard is required. This absolute self-calibration method is based on the time correlation of entangled photons pairs emitted in spontaneous parametric down conversion. The measured quantum efficiency of a Si avalanche photodiode single-photon detector agrees well with the product specifications.

Correlated two-photon imaging with true thermal light.

Received March 14, 2005; revised manuscript received May 4, 2005; accepted May 4, 2005 We report what is believed to be the first experimental demonstration of two-photon correlated imaging with true thermal light from a hollow cathode lamp. The coherence time of the source is much shorter than that of previous experiments using random scattered light from a laser. A two-pinhole mask was used as object, and the corresponding thin lens equation was well satisfied. Since thermal light sources are easier to obtain and measure than entangled light, it is conceivable that they may be used in special imaging applications.