Porcine Cloned Embryos Reconstructed with the Cell Nuclei of Tetraploid M-phase Fibroblast Cells Can Restore Normal Diploidy at the Blastocyst Stage.

The cell cycle of donor cells as a major factor that affects cloning efficiency remains debatable. G2/M phase cells as a donor can successfully produce cloned animals, but a minimal amount is known regarding nuclear remodeling events. In this study, porcine fetal fibroblasts (PFFs) were carefully synchronized at G1 or M phase as donor cells. Most of the cloned embryos reconstructed from PFFs at G1 (G1-embryos) or M (M-embryos) phase formed a pronucleus-like nucleus (PN) within 6-h post fusion (hpf), but the M-embryos formed PN earlier than the G1-embryos did. Moreover, 77.4% of the M-embryos formed two PNs, whereas the G1-embryos formed a single PN. The rate of extrusion of polar body-like structures by the M-embryos was significantly lower than that extruded by the G1-embryos (26.3% vs. 37.1%, P < 0.05), and DNA synthesis in most embryos in both groups was initiated at 9-12 hpf. Most of the M-embryos were octoploid before the first cleavage. Furthermore, 81.25% of the blastomeres of blastocysts developed from the M-embryos showed abnormal ploidy compared with those developed from the G1-embryos (22.55%). However, some of the blastomeres remained diploid in all the M-embryos tested. A portion of the blastomeres restored normal diploidy in some of the M-embryos at the blastocyst stage. This finding provides an explanation for M-embryos developing to term.

Transcriptome survey of phototransduction and clock genes in marine bivalves.

Marine animals exhibit a variety of biological rhythms, such as solar and lunar-related cycles; however, our current molecular understanding of biological rhythms in marine animals is quite limited. Identifying and understanding the expression patterns of clock genes from available transcriptomes will help elucidate biological rhythms in marine species. Here, we perform a comprehensive survey of phototransduction and circadian genes using the mantle transcriptome of the scallop Patinopecten yessoensis and compare the results with those from three other bivalves. The comparison reveals the presence of transcripts for most of the core members of the phototransduction and circadian networks seen in terrestrial model species in the four marine bivalves. Matches were found for all 37 queried genes, and the expressed transcripts from the deep sequencing data matched 8 key insect and mammalian circadian genes. This demonstrates the high level of conservation of the timekeeping mechanism from terrestrial species to marine bivalves. The results provide a valuable gene resource for studies of "marine rhythms" and also further our understanding of the diversification and evolution of rhythms in marine species.

Isolation and characterization of 48 polymorphic microsatellite markers for the blood clam Scapharca broughtonii (Arcidae).

Blood clams (Scapharca broughtonii) are widely cultivated and consumed in noutheast Asia. Forty-eight polymorphic microsatellite loci were developed for this clam using magnetic-bead hybridization enrichment. The number of alleles per locus ranged from 2 to 14. Polymorphism of these loci was assessed in 30 individuals from a population collected from coastal areas of Qingdao, China. The values of observed heterozygosity, expected heterozygosity and polymorphism information content per locus ranged from 0.1034 to 0.9655, from 0.1831 to 0.9208, and from 0.1638 to 0.8964, respectively. Forty-three of 48 loci conformed to Hardy-Weinberg equilibrium. These microsatellite loci would be useful for molecular genetic breeding, population genetics, genome mapping, and other relevant research on S. broughtonii.

Surface modification of titanium through amino group implantation.

We modified Ti surfaces by implantation of amino (NH(2+)) groups at 10(16) and 10(17) cm(-2). The implanted surfaces were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning Auger electron spectroscopy (AES), and second ion mass spectroscopy (SIMS). The experimental results showed that the implanted Ti specimens were covered by a dominant hydrocarbon overlayer due to contamination and the surface oxide layer of implanted specimens became thicker. XPS, AES, and SIMS depth profiles showed that implanted elements had a typical ion implantation distribution and that titanium nitride (TiN) was formed.

Preparation of graded porous titanium coatings on titanium implant materials by plasma spraying.

Graded porous titanium coatings have been deposited on titanium substrates for dental implants by plasma spraying in an argon atmosphere. X-ray diffraction (XRD), scanning electron microscopy (SEM), surface roughness measurement, and tensile strength tests were performed on graded porous coatings. The results showed that Ti(3)O(5) was formed in the outermost surface of the porous coatings due to oxidation. The graded porous coatings consisted of three layers. The outer layer was full of macropores with a surface roughness of approximately 100 microm. The diameter of many macropores reached and even surpassed 150 microm, which could be beneficial for tissue to grow into the coating. The middle layer consisted of a mixture of micropores and macropores. The inner layer was a very dense and tight interface layer that included mechanical, physical, and metallurgical bonding. In tensile strength tests, testing bars peeled off the coatings, because the adhesive agent fractured, but the coatings remained intact.