Genetic changes in a novel breeding population of Brassica napus synthesized from hundreds of crosses between B. rapa and B. carinata

Introgression of genomic variation between and within related crop species is a significant evolutionary approach for population differentiation, genome reorganization and trait improvement. Using the Illumina Infinium Brassica 60K SNP array, we investigated genomic changes in a panel of advanced generation new‐type Brassica napus breeding lines developed from hundreds of interspecific crosses between 122 Brassica rapa and 74 Brassica carinata accessions, and compared them with representative accessions of their three parental species. The new‐type B. napus population presented rich genetic diversity and abundant novel genomic alterations, consisting of introgressions from B. rapa and B. carinata, novel allelic combinations, reconstructed linkage disequilibrium patterns and haplotype blocks, and frequent deletions and duplications (nonrandomly distributed), particularly in the C subgenome. After a much shorter, but very intensive, selection history compared to traditional B. napus, a total of 15 genomic regions with strong selective sweeps and 112 genomic regions with putative signals of selective sweeps were identified. Some of these regions were associated with important agronomic traits that were selected for during the breeding process, while others were potentially associated with restoration of genome stability and fertility after interspecific hybridization. Our results demonstrate how a novel method for population‐based crop genetic improvement can lead to rapid adaptation, restoration of genome stability and positive responses to artificial selection.     

SPARC基因过表达对SKM-1细胞凋亡的影响

构建SPARc基因过表达载体,转染人骨髓增生异常综合征（myelodysplastic syndrome,MDS）-u／胞系SKM-1细胞,探讨SPARc基因过表达对!＆MDS细胞系SKM一1细胞凋亡的影响。XpcD—NA．SPARC为引物,PCR扩增SPARc基因;将靶基因克隆入慢病毒载体pGC—GV,构建含有删Rc基因的重组慢病毒载体pGC—GV-SPARC,测序检测正确性;将构建载体pGC-GV-5黝尺C砗专染人MDs细胞系SKM-1,流式细胞术检测转染效率,RT-PCR检测sKM-1细胞中SPARCmRNA表达,Westernblot检测SPARC蛋白表达,MTS法测定小剂量阿糖胞苷（30ng／mL）对实验组增殖抑制的影响,AnnexinV检测．洲尺c基因转染后对人SKM-1细胞凋亡的影响。结果显示,构建含有SPARc基因的重组慢病毒载体pGC-GV-SPARC转染效率为（64．25±1．42）％;转染后,SPARCmRNA及蛋白表达在靶细胞中较对照组增多。小剂量阿糖胞苷对转染组的增殖抑制率明显高于其他组。SPARC基因转染后人SKM-1细胞凋亡率较未转染组明显增高,加入阿糖胞苷后人SKM-1细胞凋亡率较对照组明显增高。由此说明,作者成功构建了携带．＆SPARc基因的慢病毒载体,转染．NSKM-1细胞系后稳定表达SPARC基因,SPARC过表达可抑制细胞增殖,且联合小剂量阿糖胞苷（30ng／mL）更有效地抑制SKM-1细胞的增殖,并诱导其凋亡。     

Natural interploidy hybridization among the key taxa involved in the origin of horticultural chrysanthemums

Understanding hybridization and introgression between natural plant populations can give important insights into the origins of cultivated species. Recent studies suggest differences in ploidy might not create such strong reproductive barriers as once thought, and thus studies into cultivated origins should examine all co-occurring taxa, including those with contrasting ploidy levels. Here, we characterized hybridization between Chrysanthemum indicum L., Chrysanthemum vestitum (Hemsley) Ling and Chrysanthemum vestitum var. latifolium (Zhou & Chen), the most important wild species involved in the origins of cultivated chrysanthemums. We analyzed the population structure of 317 Chrysanthemum accessions based on 13 microsatellite markers and sequenced chloroplast trnL-trnF for a subset of 103 Chrysanthemum accessions. We identified three distinct genetic clusters, corresponding to the three taxa. We detected 20 hybrids between species of different ploidy levels, of which 19 were between C. indicum (4x) and C. vestitum (6x) and one was between C. indicum and C. vestitum var. latifolium (6x). Fourteen hybrids between C. indicum and C. vestitum were from one of the five study sites. Chrysanthemum vestitum and C. vestitum var. latifolium share only one chloroplast haplotype. The substantially different number of hybrids between hybridizing species was likely due to different levels of reproductive isolation coupled with environmental selection against hybrids. In addition, human activities could play a role in the different patterns of hybridization among populations.     

Tumor Invasiveness,Not Lymphangiogenesis,Is Correlated with Lymph Node Metastasis and Unfavorable Prognosis in Young Breast Cancer Patients (≤35 Years)

The morbidity rate of breast cancer is on the rise, and the age of onset appears to be trending toward a young age. Breast cancer in young women (BCYW) has a number of distinctive features that differ from breast cancer in middle-aged or elderly women (BCMEW). Lymphatic metastasis plays an important role in the spread of BCYW; however, the mechanisms of lymph node metastasis (LNM) in BCYW are not clear. This study aimed to investigate the mechanism of lymphatic metastasis in BCYW and to evaluate the relationships between lymphangiogenesis, the expression of matrix metalloproteinase 9 (MMP-9) and vascular endothelial growth factor C (VEGF-C) expression, clinicopathological characteristics, and prognosis. Using immunohistochemistry, MMP-9, VEGF-C and the level of lymphatic microvessel density (LMVD) were analyzed in 106 cases of breast invasive ductal carcinoma and 20 cases of breast proliferative lesions. Compared with BCMEW, BCYW had higher MMP-9 expression, higher LNM, and more adverse prognoses. In BCYW, high MMP-9 expression was positively correlated with LNM and impaired survival time. However, in BCMEW, MMP-9 expression was not correlated with LNM or survival time. In addition, high VEGF-C expression was positively correlated with a high level of LMVD in both BCYW and BCMEW. Nevertheless, a high level of LMVD was not correlated with LNM or survival time in the two groups. More importantly, univariate and multivariate survival analysis showed that MMP-9 expression and LNM were independent prognostic factors in BCYW. Our present study indicates that lymphangiogenesis induced by VEGF-C is augmented in breast cancer; however, a higher level of lymphangiogenesis has no significant impact on LNM or survival time. We suggest that tumor invasiveness, rather than lymphangiogenesis, plays an important role in LNM among BCYW. Moreover, MMP-9 and LNM were independent prognostic factors for BCYW.     

Stem cell aging is controlled both intrinsically and extrinsically in the Drosophila ovary

It is widely postulated that tissue aging could be, at least partially, caused by reduction of stem cell number, activity, or both. However, the mechanisms of controlling stem cell aging remain largely a mystery. Here, we use Drosophila ovarian germline stem cells (GSCs) as a model to demonstrate that age-dependent decline in the functions of stem cells and their niche contributes to overall stem cell aging. BMP signaling activity from the niche significantly decreases with age, and increasing BMP signaling can prolong GSC life span and promote their proliferation. In addition, the age-dependent E-cadherin decline in the stem cell-niche junction also contributes to stem cell aging. Finally, overexpression of SOD, an enzyme that helps eliminate free oxygen species, in either GSCs or their niche alone can prolong GSC life span and increase GSC proliferation. Therefore, this study demonstrates that stem cell aging is controlled extrinsically and intrinsically in the Drosophila ovary.     

转Bt基因植物中外源基因时空动态表达的研究现状

在转Bt基因植株中 ,外源基因的时空动态表达对于害虫的防治和转基因安全评价管理具有重要意义。利用生物测定法和酶联免疫吸附测定法 (ELISA) ,对植物不同组织在同一发育阶段、同一组织在不同的发育阶段以及不同转基因植株的外源基因的时空动态表达进行研究。本文综述了转基因植物中外源基因时空动态表达的研究进展和现状。     

Hedychium menghaiense (Zingiberaceae),a new species from Yunnan,China

Hedychium menghaiense X.Hu & N.Liu,a new species of the Zingiberaceae from Yunnan Province,China,is described and illustrated.The new species is currently known only from its type locality,Nannuoshan Mountain,Menghai County,growing under evergreen broad-leaved forests at altitudes of 1400-1700 m.It is similar to Hedychium forrestii Diels,but differs in its narrower and emarginate labellum folded inwards lengthwise,narrower staminodes,and scarlet stamen.The recognition of the new species is supported by the ...     

Callus induction and shoot organogenesis from anther cultures of Curcuma attenuata Wall

Curcuma attenuata is a highly valued ornamental. This study provides the first report on C. attenuata shoot organogenesis and plant regeneration. Immature anthers derived from 5 to 7?cm long inflorescences were isolated and cultured on different variations of Murashige and Skoog (MS) media to induce callus and then shoot organogenesis. When the 2-mm long anthers in which microspores were at the uninucleate developmental stage were cultured in the dark on MS medium containing 13.6???M 2,4-dichlorophenoxyacetic acid (2,4-D) and 2.3???M kinetin (KT) for 15?days and then transferred to 40???mol?m^?2?s^?1 fluorescent light for 30?days, the percentage callus induction reached 33.3?%. After callus was transferred to various differentiation media and cultured in the light, 33.1?% of all callus cultures could differentiate into adventitious shoots on MS medium supplemented with 22.0???M 6-benzyladenine (BA), 0.53???M ??-naphthaleneacetic acid (NAA) and 1.4???M thidiazuron (TDZ) after culturing for 60?days. Over 95?% of plantlets survived after transplanting plantlets into trays with a mixture of sand and perlite (2: 1) for 20?days. Chromosome number, determined from the root tips of young plantlets, indicated that all plantlets were diploid (2n?=?84).