The giant panda (Ailurapoda melanoleuca) somatic nucleus can dedifferentiate in rabbit ooplasm and support early development of the reconstructed egg

The giant panda skeletal muscle cells, uterus epithelial cells and mammary gland cells from an adult individual were cultured and used as nucleus donor for the construction of interspecies embryos by transferring them into enucleated rabbit eggs. All the three kinds of somatic cells were able to reprogram in rabbit ooplasm and support early embryo development, of which mammary gland cells were proven to be the Lest, followed by uterus epithelial cells and skeletal muscle cells. The experiments showed that direct injection of mammary gland cell into enucleated rabbit ooplasm, combined with in vivo development in ligated rabbit oviduct, achieved higher blastocyst development than in vitro culture after the somatic cell was injected into the perivitelline space and fused with the enucleated egg by electrical stimulation. The chromosome analysis demonstrated that the genetic materials in reconstructed blastocyst cells were the same as that in panda somatic cells. In addition, giant panda mitochondrial DNA (mtDNA) was shown to exist in the interspecies reconstructed blastocyst. The data suggest that (i) the ability of ooplasm to dedifferentiate somatic cells is not species-specific; (ii) there is compatibility between interspecies somatic nucleus and ooplasm during early development of the reconstructed egg.

Microsatellite DNA analysis proves nucleus of interspecies reconstructed blastocyst coming from that of donor giant panda

A method for DNA isolation from early development of blastocyst and further analysis of nuclear and mitochondrial DNA was developed in present study. Total DNA was prepared from interspecies reconstructed blastocyst and a giant panda specific microsatellite locus g(010) was successfully amplified. DNA sequencing of the PCR product showed that two sequences of reconstructed blastocysts are the same as that of positive control giant panda. Our results prove that the nucleus of interspecies reconstructed blastocyst comes from somatic nucleus of donor giant panda.

Phylogeny and biogeography of the Petaurista philippensis complex (Rodentia : Sciuridae), inter- and intraspecific relationships inferred from molecular and morphometric analysis

With modified DNA extraction and Purification protocols, the complete cytochrome b gene sequences (1140 bp) were determined from degraded museum specimens. Molecular analysis and morphological examination of cranial characteristics of the giant flying squirrels of Petaurista philippensis complex (P. grandis, P. hainana, and P. yunanensis) and other Petaurista species yielded new insights into long-standing controversies in the Petaurista systematics. Patterns of genetic variations and morphological differences observed in this study indicate that P. hainana, P. albiventer, and P. yunanensis can be recognized as distinct species, and P. grandis and P. petaurista are conspecific populations. Phylogenetic relationships reconstructed by using parsimony, likelihood, and Bayesian methods reveal that, with P. leucogenys as the basal branch, all Petaurista groups formed two distinct clades. Petaurista philippensis, P. hainana, P. yunanensis, and P. albiventer are clustered in the same clade, while P. grandis shows a close relationship to P. petaurista. Deduced divergence times based on Bayesian analysis and the transversional substitution at the third codon suggest that the retreating of glaciers and upheavals or movements of tectonic plates in the Pliocene-Pleistocene were the major factors responsible for the present geographical distributions of Petaurista groups. (c) 2005 Elsevier Inc. All rights reserved.

Sequencing, annotation and comparative analysis of nine BACs of giant panda (Ailuropoda melanoleuca)

A 10-fold BAC library for giant panda was constructed and nine BACs were selected to generate finish sequences. These BACs could be used as a validation resource for the de novo assembly accuracy of the whole genome shotgun sequencing reads of giant panda newly generated by the Illumina GA sequencing technology. Complete sanger sequencing, assembly, annotation and comparative analysis were carried out on the selected BACs of a joint length 878 kb. Homologue search and de novo prediction methods were used to annotate genes and repeats. Twelve protein coding genes were predicted, seven of which could be functionally annotated. The seven genes have an average gene size of about 41 kb, an average coding size of about 1.2 kb and an average exon number of 6 per gene. Besides, seven tRNA genes were found. About 27 percent of the BAC sequence is composed of repeats. A phylogenetic tree was constructed using neighbor-join algorithm across five species, including giant panda, human, dog, cat and mouse, which reconfirms dog as the most related species to giant panda. Our results provide detailed sequence and structure information for new genes and repeats of giant panda, which will be helpful for further studies on the giant panda.

The sequence and de novo assembly of the giant panda genome

Using next-generation sequencing technology alone, we have successfully generated and assembled a draft sequence of the giant panda genome. The assembled contigs (2.25 gigabases (Gb)) cover approximately 94% of the whole genome, and the remaining gaps (0.05 Gb) seem to contain carnivore-specific repeats and tandem repeats. Comparisons with the dog and human showed that the panda genome has a lower divergence rate. The assessment of panda genes potentially underlying some of its unique traits indicated that its bamboo diet might be more dependent on its gut microbiome than its own genetic composition. We also identified more than 2.7 million heterozygous single nucleotide polymorphisms in the diploid genome. Our data and analyses provide a foundation for promoting mammalian genetic research, and demonstrate the feasibility for using next-generation sequencing technologies for accurate, cost-effective and rapid de novo assembly of large eukaryotic genomes.

Predation on giant flying squirrels (Petaurista philippensis) by black crested gibbons (Nomascus concolor jingdongensis) at Mt. Wuliang, Yunnan, China

Predation on vertebrates is infrequent in gibbons. In a 14-month field study of the central Yunnan black crested gibbon (Nomascus concolor jingdongensis) at Mt. Wuliang, Yunnan, China, we observed gibbons attacking, killing and eating giant flying squirre

First report of two Balantidium species from the Chinese giant salamander, Andrias davidianus: Balantidium sinensis Nie 1935 and Balantidium andianusis n. sp.

Two ciliated protozoa, Balantidium sinensis Nie 1935 and Balantidium andianusi n. sp., were isolated from the feces of a wild Chinese giant salamander (Andrias davidianus) captured from the mountainous area of Shiyan, Hubei Province, Central China in October 2006. It is the first report of Balantidium species inhabiting Cryptobranchoidea amphibians. The occurrence of B. sinensis in A. davidianus should be a new record because the type specimens were first discovered and named by Nie in 1935 from Rana nigromaculata and Rana plancyi. For the lack of enough descriptions of taxonomic features in the previous report, it was re-described in detail and compared with Nie's type specimens and B. giganteum to complete the morphological descriptions in the present work. B. andianusi n. sp. was considered to be a new species based on its unique morphological characteristics, especially the high length/width ratio of the vestibulum (8:1). Comparisons were also made among Balantidium species that were found from urodele amphibians.

The giant zooxanthellae-bearing ciliate Maristentor dinoferus (Heterotrichea) is closely related to folliculinidae

The small subunit rDNA sequence of Maristentor dinoferus (Lobban, Schefter, Simpson, Pochon, Pawlowski, and Foissner, 2002) was determined and compared with sequences from other Heterotrichea and Karyorelictea. Maristentor resembles Stentor in basic morphology and had been provisionally assigned to Stentoridae. However, our phylogenetic analyses show that Maristentor is more closely related to Folliculinidae. Our results support the creation of a separate family for Maristentor, Maristentoridae n. fam., and also confirm the phylogenetic grouping of Folliculindae, Stentoridae, Blepharismidae, and Maristentoridae, which we informally call 'stentorids'. Maristentor, rather than Stentor itself, appears to be most significant in understanding the origins of folliculinids from their aloricate ancestors. Our analyses suggest continued uncertainty in the exact placement of the root of heterotrichs with this phylogenetic marker.

Co doping enhanced giant magnetocaloric effect in Mn1-xCoxAs films epitaxied on GaAs (001)

A giant magnetocaloric effect was found in series of Mn1-xCoxAs films epitaxied on GaAs (001). The maximum magnetic entropy change caused by a magnetic field of 4 T is as large as 25 J/kg K around room temperature, which is about twice the value of pure MnAs film. The observed small thermal hysteresis is more suitable for practical application. Growing of layered Mn1-xCoxAs films with Co concentration changing gradually may draw layered active magnetic regenerator refrigerators closer to practical application. Our experimental result may provide the possibility for the combination of magnetocaloric effect and microelectronic circuitry.

Monolithically integrated transceiver with novel Y-branch by bundle integrated waveguide for fibre optic gyroscope

A novel Y-branch based monolithic transceiver with a superluminescent diode and a waveguide photodiode (Y-SDL-PD) is designed and fabricated by the method of bundle integrated waveguide (BIG) as the scheme for monolithic integration and angled Y-branch as the passive bi-directional waveguide. The simulations of BIG and Y-branches show low losses and improved far-field patterns, based on the beam propagation method (BPM). The amplified spontaneous emission of the device is up to 10mW at 120mA with no threshold and saturation. Spectral characteristics of about 30 nm width and less than 1 dB modulation are achieved using the built-in anti-lasing ability of Y-branch. The beam divergence angles in horizontal and vertical directions are optimized to as small as 12 degrees x 8 degrees, resulting in good fibre coupling.

Coulomb blockade double-dot Aharonov-Bohm interferometer: Giant fluctuations

Electron transport through two parallel quantum dots is a kind of solid-state realization of double path interference We demonstrate that the inter-clot Coulomb correlation and quantum coherence would result in strong current fluctuations with a divergent Fano factor at zero frequency. We also provide physical interpretation for this surprising result, which displays its generic feature and allows us to recover this phenomenon in more complicated systems. (C) 2009 Elsevier B.V. All rights reserved.

Dielectric relaxation and giant dielectric constant of Nb-doped CaCu3Ti4O12 ceramics under dc bias voltage

CaCu3Ti(4-x)Nb(x)O(12) (x = 0, 0.01, 0.08, 0.2) ceramics were fabricated by a conventional solid-state reaction method. The ceramics showed the body-centered cubic structure without any foreign phases and the grain size decreases with Nb doping. Two Debye-type relaxations were observed for the Nb-doped samples at low frequency and high frequency, respectively. The complex electric modulus analysis revealed that the surface layer, grains and grain boundaries contributed to the dielectric constant. The low-frequency dielectric constant relative to the surface layer decreased to a minimum and then increased with the dc bias voltage at 100 Hz, which were well explained in terms of a model containing two metal oxide semiconductors in series, confirming the surface layer in the ceramics. The shift voltage V-B corresponding to the minimal capacitance increased with increase of the composition x. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optical microwave generation using two parallel DFB lasers integrated with Y-branch waveguide coupler

A new device of two parallel distributed feedback (DFB) lasers integrated monolithically with Y-branch waveguide coupler was fabricated by means of quantum well intermixing. Optical microwave signal was generated in the Y-branch waveguide coupler through frequency beating of the two laser modes coming from two DFB laser in parallel, which had a small difference in frequency. Continuous rapid tuning of optical microwave signal from 13 to 42 GHz were realized by adjusting independently the driving currents injected into the two DFB lasers.

Giant and zero electron g factors of dilute nitride semiconductor nanowires

The electronic structures and electron g factors of InSb1-sNs and GaAs1-sNs nanowires and bulk material under the magnetic and electric fields are investigated by using the ten-band k.p model. The nitrogen doping has direct and indirect effects on the g factors. A giant g factor with absolute value larger than 900 is found in InSb1-sNs bulk material. A transverse electric field can increase the g factors, which has obviously asymmetric effects on the g factors in different directions. An electric field tunable zero g factor is found in GaAs1-sNs nanowires. (C) 2007 American Institute of Physics.