Evidence of a pluripotent human embryonic stem cell line derived from a cloned blastocyst

Somatic cell nuclear transfer (SCNT) technology has recently been used to generate animals with a common genetic composition. In this study, we report the derivation of a pluripotent embryonic stem (ES) cell line (SCNT-hES-1) from a cloned human blastocyst. The SCNT-hES-1 cells displayed typical ES cell morphology and cell surface markers and were capable of differentiating into embryoid bodies in vitro and of forming teratomas in vivo containing cell derivatives from all three embryonic germ layers in severe combined immunodeficient mice. After continuous proliferation for more than 70 passages, SCNT-hES-1 cells maintained normal karyotypes and were genetically identical to the somatic nuclear donor cells. Although we cannot completely exclude the possibility that the cells had a parthenogenetic origin, imprinting analyses support a SCNT origin of the derived human ES cells.     

FBXW7 targets mTOR for degradation and cooperates with PTEN in tumor suppression

The enzyme mTOR (mammalian target of rapamycin) is a major target for therapeutic intervention to treat many human diseases, including cancer, but very little is known about the processes that control levels of mTOR protein. Here, we show that mTOR is targeted for ubiquitination and consequent degradation by binding to the tumor suppressor protein FBXW7. Human breast cancer cell lines and primary tumors showed a reciprocal relation between loss of FBXW7 and deletion or mutation of PTEN (phosphatase and tensin homolog), which also activates mTOR. Tumor cell lines harboring deletions or mutations in FBXW7 are particularly sensitive to rapamycin treatment, which suggests that loss of FBXW7 may be a biomarker for human cancers susceptible to treatment with inhibitors of the mTOR pathway.     

广州市城区居住区绿化质量研究

通过对广州市城区居住区绿地绿化进行抽样调查,利用调查数据对其居住区的绿化质昔进行分析,结果表明:广州市居住区植物多样性各指标整体水平较高,但内部差异很大.新居住区绿化植物过分强调美化效益和经济效益,忽略生态效益和环境效益,这种发展趋势是不可持续的.其次,居住区绿化植物,本地物种数量过少;居住区空间绿化较少,但晕增长趋势...     

Genetic diversity and population structure of Raffaelea quercus‐mongolicae,a fungus associated with oak mortality in South Korea

Raffaelea quercus‐mongolicae is a fungus associated with oak wilt and deemed to cause extensive oak mortality in South Korea. Since the discovery of this fungus on a dead Mongolian oak (Quercus mongolica) in 2004, the mortality continued to spread southwards in South Korea. Despite continued expansion of the disease and associated significant impacts on forest ecosystems, information is lacking about the origin and genetic diversity of R. quercus‐mongolicae. Restriction‐site‐associated DNA (RAD) sequencing was used to assess genetic diversity and population structure among five populations (provinces) of R. quercus‐mongolicae in South Korea. In total, 179 single nucleotide polymorphisms (SNPs) were identified among 2,639 RAD loci across the nuclear genome of the 54 R. quercus‐mongolicae isolates (0.0012 SNPs per bp), which displayed an overall low expected heterozygosity and no apparent population structure. The low genetic diversity and no apparent population structure among South Korean populations of this ambrosia beetle‐vectored fungus support the hypothesis that this fungus was introduced to South Korea.     

Induction of Tolerance to Fusarium Wilt and Defense-Related Mechanisms in the Plantlets of Susceptible Berangan Banana Pre-lnoculated with Pseudomonas sp. （UPMP3） and Burkholderia sp. （UPMB3）

This study is aimed at assessing the ability of two endophytic bacteria originally isolated from healthy oil palm roots, Pseudomonas sp. （UPMP3） and Burkholderia sp. （UPMB3） to induce resistance in susceptible Berangan banana against Fusarium oxysporum race 4 （FocR4）. Increased accumulation of resistance-related enzymes such as peroxidase （PO）, phenylalanine ammonia lyase （PAL）, lignithioglycolic acid （LTGA）, and pathogenesis-related （PR） proteins （ehitinase and β-1,3-glucanase） has been observed in plantlets treated with endophytic bacteria UPMP3 and UPMB3 singly or as mixture under glasshouse conditions. Pre-inoculation of banana plantlets with UPMP3 showed a significant reduction in Fusarium wilt incidence 72 d after challenged inoculation with FocR4. UPMB3 was less effective in suppressing Fusarium wilt compared to UPMP3, whereas, the mixture of both endophytes showed an intermediate effect. Based on these results, it is concluded that UPMP3 could be a promising biological control agent that can trigger resistance against Fusarium wilt in susceptible Berangan banana.     

Isolation of a cDNA from the virus responsible for enterically transmitted non-A, non-B hepatitis

Major epidemic outbreaks of viral hepatitis in underdeveloped countries result from a type of non-A, non-B hepatitis distinct from the parenterally transmitted form. The viral agent responsible for this form of epidemic, or enterically transmitted non-A, non-B hepatitis (ET-NANBH), has been serially transmitted in cynomolgus macaques (cynos) and has resulted in typical elevation in liver enzymes and the detection of characteristic virus-like particles (VLPs) in both feces and bile. Infectious bile was used for the construction of recombinant complementary DNA libraries. One clone, ET1.1, was exogenous to uninfected human and cyno genomic liver DNA, as well as to genomic DNA from infected cyno liver. ET1.1 did however, hybridize to an approximately 7.6-kilobase RNA species present only in infected cyno liver. The translated nucleic acid sequence of a portion of ET1.1 had a consensus amino acid motif consistent with an RNA-directed RNA polymerase; this enzyme is present in all positive strand RNA viruses. Furthermore, ET1.1 specifically identified similar sequences in complementary DNA prepared from infected human fecal samples collected from five geographically distinct ET-NANBH outbreaks. Therefore, ET1.1 represents a portion of the genome of the principal viral agent, to be named hepatitis E virus, which is responsible for epidemic outbreaks of ET-NANBH.     

Polymer gate dielectric surface viscoelasticity modulates pentacene transistor performance

Nanoscopically confined polymer films are known to exhibit substantially depressed glass transition temperatures (Lg's) as compared to the corresponding bulk materials. We report here that pentacene thin films grown on polymer gate dielectrics at temperatures well below their bulk Tg's exhibit distinctive and abrupt morphological and microstructural transitions and thin-film transistor (TFT) performance discontinuities at well-defined growth temperatures. The changes reflect the higher chain mobility of the dielectric in its rubbery state and are independent of dielectric film thickness. Optimization of organic TFT performance must recognize this fundamental buried interface viscoelasticity effect, which is detectable in the current-voltage response.     

Genotypic difference in spikelet sterility response to air temperature during the reproductive stage of rice

This experiment was conducted to evaluate the varietal differences of spikelet sterility response to air temperature during the reproductive stage. Six rice varieties differing in maturity group (early-maturing; Unkwangbyeo, Odaebyeo, medium-maturing; Andabyeo, Hwasungbyeo, and mid-late maturing; Donganbyeo, Chuchungbyeo) were grown under ambient temperature (AT) conditions before being transferred to the temperature-controlled plastic houses. For the synchronization of the growth stage, 15 rice seedlings (2011) and 10 rice seedlings (2012) per pot were transplanted in a circle and only main stems were grown by removing tillers at early stage of their emergence. At the initial heading stage, pots for each variety were transferred to the four plastic houses that were controlled to AT, AT + 1.5°C, AT + 3.0°C, and AT + 5.0°C, respectively. Spikelet fertility was significantly decreased due to high temperature-induced spikelet sterility at AT + 3.0 and/or AT + 5.0°C treatment during flowering time in 2011. Spikelet fertility in 2012 was much lower than in 2011 even at the AT treatment because of high temperature-induced spikelet sterility at the micosporogenesis stage. Critical temperature (Tc) that induces 50% spikelet sterility at flowering time was estimated by fitting the temperature response of spikelet fertility to a logistic function. Tc ranged from 34.6°C (Odaebyeo) to 39.7°C (Hwasungbyeo), Odaebyeo being significantly more sensitive to high temperature-induced spikelet sterility than the other varieties. This result has shown that response of spikelet sterility to higher temperature is different according to rice varieties. However, further study should be done to arrive at a concrete conclusion.     

不同采烤方式对上部烟叶质量及效益的影响

针对安康烟区上部烟叶组织结构特点,对上部烟叶一次带茎采烤方式比较研究,结果表明：上部烟叶带茎一次采烤与不带茎采烤方式相比,上中等烟比例极显著提高18.94%,均价极显著提高18.19%,原烟外观质量明显改善,橘黄烟比例明显增加,结构更加疏松,油分增多,色度增强,但用工、用煤、用电等总成本显著增加,每千克干烟增加1.14元。