论两晋南朝尚书郎仕途角色的嬗变

尚书郎在西晋尚属起家官,到东晋南朝,尚书郎在仕宦途径中主要作为迁转官出现。在该时期官员的仕宦途径中,尚书郎是一个重要的阶梯,任职者往往容易升迁到更高级的职务。

Beyond tumorigenesis: cancer stem cells in metastasis

The importance of cancer stem cells （CSCs） in tumor-initiation has been firmly established in leukemia and recently reported for a variety of solid tumors. However, the role of CSCs in multistage cancer progression, particularly with respect to metastasis, has not been well-defined. Cancer metastasis requires the seeding and successful colonization of specialized CSCs at distant organs. The biology of normal stem cells and CSCs share remarkable similarities and may have important implications when applied to the study of cancer metastasis. Furthermore, overlapping sets of molecules and pathways have recently been identified to regulate both stem cell migration and cancer metastasis. These molecules constitute a complex network of cellular interactions that facilitate both the initiation of the pre-metastasis niche by the primary tumor and the formation of a nurturing organ microenvironment for migrating CSCs. In this review, we surveyed the recent advances in this dynamic field and propose a unified model of cancer progression in which CSCs assume a central role in both tumorigenesis and metastasis. Better understanding of CSCs as a fundamental component of the metastatic cascade will lead to novel therapeutic strategies against metastatic cancer.

Expression of Endogenous Beta Retroviruses and Hyal-2 mRNA in Immune Organs of Fetuses and Lambs

Endogenous beta retroviruses (enJSRV) are highly homologous with Jaagsiekte sheep retrovirus (exJSRV),this exogenous retrovirus is the aetiological agent of ovine pulmonary adenocarcinoma (OPA). The aim of this study was to clarify the function of enJSRV and the immunological mechanisms of its corresponding antibody, that is undetectable in JSRV-infected ovine serum. The expression of enJSRV envelope protein and Hyal-2 mRNA in immune organs and lungs of ovine fetuses and lambs were analyzed by Real-Time reverse transcription PCR and In Situ Hybridization using specific probes. In Situ Hybridization results indicated that the enJSRV envelope protein and Hyal-2 mRNA were expressed in thymus, spleen, mesenteric lymph nodes and lungs at different times, while no positive signals were detected in the negative controls. On the other hand, results from Real-Time reverse transcription PCR analysis showed that in 130d fetuses and 3d newborn lambs the enJSRV mRNA levels were much higher in organs associated with the immune system than that in lungs, especially in the thymus and spleen, but levels of Hyal-2 mRNA expression was not significantly different in all collected tissue. These results provided evidence from an immunology point of view to understand why the circulating antibodies against exJSRV are undetectable in JSRV-infected ovine, and will help to unravel the pathogenesis of JSRV-infected ovine.

P68 RNA helicase is a nucleocytoplasmic shuttling protein

P68 RNA helicase is a prototypical DEAD box RNA helicase. The protein plays a very important role in early organ development and maturation. Consistent with the function of the protein in transcriptional regulation and pre-mRNA splicing, p68 was found to predominately localize in the cell nucleus. However, recent experiments demon- strate a transient cytoplasmic localization of the protein. We report here that p68 shuttles between the nucleus and the cytoplasm. The nucleocytoplasmic shuttling of p68 is mediated by two nuclear localization signal and two nuclear exporting signal sequence elements. Our experiments reveal that p68 shuttles via a classical RanGTPase-dependent pathway.

Charge transfer and orbital reconstruction of non‐noble transition metal single‐atoms anchored on Ti_(2)CT_(x)‐MXenes for highly selective CO_(2) electrochemical reduction

Inspired by MXene nanosheets and their regulation of surface functional groups,a series of Ti_(2)C‐based single‐atom electrocatalysts(TM@Ti_(2)CT_(x),TM=V,Cr,Mn,Fe,Co,and Ni)with two dif‐ferent functional groups(T=–O and–S)was designed.The CO_(2)RR catalytic performance was stud‐ied using well‐defined ab initio calculations.Our results show that the CO_(2) molecule can be more readily activated on TM@Ti_(2)CO_(2) than the TM@Ti_(2)CS_(2) surface.Bader charge analysis reveals that the Ti_(2)CO_(2) substrate is involved in the adsorption reaction,and enough electrons are injected into the 2π*u orbital of CO_(2),leading to a V‐shaped CO_(2) molecular configuration and partial negative charge distribution.The V‐shaped CO_(2) further reduces the difficulty of the first hydrogenation reac‐tion step.The calculatedΔG of the first hydrogenation reaction on TM@Ti_(2)CO_(2) was significantly lower than that of the TM@Ti_(2)CS_(2) counterpart.However,the subsequent CO_(2) reduction pathways show that the UL of the potential determining step on TM@Ti_(2)CS_(2) is smaller than that of TM@Ti_(2)CO_(2).Combining the advantages of both TM@Ti_(2)CS_(2) and TM@Ti_(2)CO_(2),we designed a mixed functional group surface with–O and–S to anchor TM atoms.The results show that Cr atoms an‐chored on the surface of mixed functional groups exhibit high catalytic activity for the selective production of CH4.This study opens an exciting new avenue for the rational design of highly selec‐tive MXene‐based single‐atom CO_(2)RR electrocatalysts.

NECK LEAF 1, a GATA type transcription factor, modulates organogenesis by regulating the expression of multiple regulatory genes during reproductive development in rice

In the monocot rice species Oryza sativa L., one of the most striking morphological processes during reproductive development is the concurrence of panicle development with the sequential elongation of upper internodes （UPIs）. To elucidate the underlying molecular mechanisms, we cloned the rice gene NECK LEAF 1 （NL1）, which when mutated results in delays in flowering time, smaller panicles with overgrown bracts and abnormal UPI elongation patterns. The NL1 gene encodes a GATA-type transcription factor with a single zinc finger domain, and its transcripts are de- tected predominantly in the bract primordia, which normally degenerate in the wild-type plants. Overexpression of NL1 in transgenic plants often gives rise to severe growth retardation, less vegetative phytomers and smaller leaves, suggesting that NL1 plays an important role in organ differentiation. A novel mutant allele of PLASTOCHRON1 （PLAD, a gene known to play a key role in regulating leaf initiation, was identified in this study. Genetic analysis demonstrated an interaction between nil and plal, with NL1 acting upstream of PLA1. The expression level and spatial pattern of PLA1 were found to be altered in the nil mutant. Furthermore, the expression of two regulators of flowering, Hd3a and OsMADS1, was also affected in the nil mutant. On the basis of these findings, we propose that NL1 is an intrinsic factor that modulates and coordinates organogenesis through regulating the expression of PLA1 and other regulatory genes during reproductive development in rice.

Impacts of long-term ridge culture on aggregate stability in purple paddy soil of Sichuan basin

Ridge culture is a special conservation tillage method, but the long-term influence of this tillage system on soil aggregate-size stability in paddy fields is largely unknown in southwest of China. The paper is to evaluate soil aggregate stability and to determine the relationship between soil organic carbon (SOC) and soil aggregate stability. Soil samples at 0 cm-20 cm layer were adopted from a long-term (16 a) field experiment including conventional tillage: plain culture, summer rice crop and winter upland crop under drained conditions (PUR-r); and conservation tillage: ridge culture without tillage, summer rice and winter fallow with floodwater layer annually (NTR-f), winter upland crop under drained conditions (NTR-r), and wide ridge culture without tillage, summer rice crop and winter upland crop under conditions (NTRw-r), respectively. Different pretreatments, such as slaking in fast wetting, wetting and subsequent slaking, were applied to simulate the breakdown mechanisms of aggregates in paddy soil. The results show that soil particles contents were mainly consisted of silt (0.050 mm to 1.000 mm) in fraction of 42.9% to 51.2%, sand (0.050 mm to 0.001 mm) in fraction of 28.0% to 31.8%, and clay (<0.001 mm) in fraction of 17.9% to 25.4%. The amount of aggregate-size was greatly observed in fraction of 2.000 mm-6.720 mm under ridge culture in paddy soil (more than 50$) under slaking and wetting pretreatment. The proportion of soil macro-aggregates (>0.250 mm) in conservation tillage was greatly higher than that in conventional tillage under subsequent fast slaking treatment. Minimal differences of aggregate stability between slaking in fast wetting and wetting were observed, while significant differences were found between ridge culture and plain culture. The aggregate stability under slaking treatment ranked in the order of NTR-r>NTRw-r> NTR-f > PUR-r, while under wetting was NTRw-r > NTR-r > NTR-f >PUR-r. There was a positive correlation between the aggregate stability and SOC concentration under wetting, and a low correlation was observed under slaking pretreatment. Soil exposure with tillage and lack of rice/rape-seed stubble inputs caused declines in aggregation and organic carbon, both of which make soil susceptible to water erosion. Adoption of ridge culture with no-tillage integrated with crop rotation and stubble mulch significantly altered soil organic concentration. It was a valuable conservation practice for soil aggregation and soil organic carbon sequestration on paddy soil.

When Sensory Substitution Devices Strike Back： An Interactive Training Paradigm

A sensory substitution device （SSD） is a technology that translates information for one sensory modality, like vision, into information for use by another, like touch. Though SSDs have been in existence for over four decades, effective training techniques for their use are rarely discussed. In this paper, we compare three training strategies on a particular SSD known as the vOICe. These comparisons were conducted using a minimal but active search and localization task of luminescent discs. These studies show that an interactive training paradigm, which combines the efforts of two trainees at the same time in a tag-like game, is more effective than passive training at a computer console or active training involving search and localization of luminescent discs. This finding supports philosophical views of perception that take interaction with the environment seriously. In particular, we argue that these findings are in support of certain features of the extended mind view as proposed by Andy Clark （2008）. In particular, the study suggests that when environmental conditions are responsive to one＇s behavioral activity, the activity itself is enhanced, as is predicted by the extended mind view.

High efficiency DNA delivery into swine oocytes and embryos by electronic pulse delivery (EPD)

The production of transgenic swine for xenotransplantation has been proposed as an optimal option to overcome the chronic shortage of human organ donors. Generation of genetically engineered swine has been elusive due to the difficulties in gene transfer. In order to achieve effective gene delivery, a key step for the genetic modification, we applied electronic pulse delivery (EPD) technology to introduce HZKb-DC DNA construct into swine eggs. Using the developed EPD ProtocolsTM, we have achieved good viability of the EPD treated oocytes, satisfactory embryonic development of the EPD treated embryos, and stable DNA transfer into the swine embryos with high efficiency. Thus, application of the EPD technology promises to effectively facilitate the generation of large trangenic mammals.

Transcriptome of intraperitoneal organs of starry flounder Platichthys stellatus challenged by Edwardsiella ictaluri JCM1680

Platichthys stellatus is an economically important marine bony fish species that is cultured in China on a large scale.However,very little is known about its immune-related genes.In this study,the transcriptome of the immune organs ofP.stellatus that were intraperitoneally challenged with the pathogen Edwardsiella ictaluri JCM1680 is analyzed.Total RNA from four tissues(spleen,kidney,liver,and intestine) was mixed equally and then sequenced on an Illumina HiSeq 2000 platform.Overall,28 465 813 quality reads were generated and assembled into 43 061 unigenes.Similarity searches against public protein sequence databases were used to annotate 28 291 unigenes(65.7%of the total),368 of which were associated with immunoregulation,including 188 related to immunity response.Additionally,the transcript levels of immunity response unigenes annotated as related to tumor necrosis factor(TNF),TNF receptor,chemokine,major histocompatibility complex,and interleukin-6 were investigated in the different tissues of normal and infected P.stellatus by real-time quantitative PCR.The results confirmed that the unigenes identified in the transcriptome database were indeed expressed and up-regulated in infected P.stellatus.To our knowledge,this is the first report of the sequencing and analysis of the transcriptome of P.stellatus.These findings provide insights into the transcriptomics and immunogenetics of bony fish.

Structural basis of immunosuppression by the therapeutic antibody daclizumab

Interleukin-2 （IL）-2 signaling plays a pivotal role in the activation of immune responses, and drugs that block this pathway have been shown to be effective for the immunosuppression in patients with organ transplantation to alleviate/eliminate allograft rejection. The first humanized monoclonal antibody （mAb） daclizumab falls into this category and shows high specificity and affinity against a key component of the IL-2 receptor complex, namely IL-2Ra. To reveal the molecular mechanism of the inhibition of the IL-2 signaling pathway by dacllzumab, we determined the crystal structures of the daclizumab Fab in free form and in complex with the IL-2Ra ectodomain at 2.6 and 2.8 A resolution, respectively. The daclizumab Fab adopts a similar conformation in the presence or absence of the IL- 2Ra ectodomain. The antigen-binding site of daclizumab is mainly composed of live complementarity determining regions （CDRs） that form a large positively charged surface depression and two flanking patches that are generally hydrophobic. The conformational epitope consists of several discontinuous segments of the IL-2Ru ectodomain, a large portion of which overlaps with the regions that interact with IL-2, suggesting that the binding of daclizumab to IL-2Ra would prevent the IL-2 binding to IL-2Ra and the subsequent formation of the IL-2fIL-2Ra[~/c complex, and therefore block the IL-2 signaling pathway. These results also have implications for the design and development of improved mAb drugs targeting IL-2Ra.

EXPRESSION OF HUMAN α-GALACTOSIDASE AND α1,2-FUCOSYL-TRANSFERASE GENES MODIFIES THE CELL SURFACE GALα1,3GAL ANTIGEN AND CONFERS RESISTANCETO HUMAN SERUM-MEDIATED CYTOLYSIS

Objective To explore the strategies which reduce the amount of xenoantigen Galα1, 3 Gal. Methods Human α-galactosidase gene and α1,2-fucosyltransferase gene were transferred into cul-tured porcine vascular endothelial cells PEDSV.15 and human α-galactosidase transgenic mice were produced. The Galα1,3Gal on the cell surface and susceptibility of cells to human antibody-mediated lysis were analyzed. Results Human α-galactosidase gene alone reduced 78% of Galα1,3Gal on PEDSV.15 cell surface while human α-galactosidase combined with α1,2-fucosyltransferase genes removed Galα1,3Gal completely. Decrease of Galα1,3Gal could reduce susceptibility of cells to human antibody-mediated lysis, especially during co-expression of α-galactosidase gene and α1,2-fucosyltransferase gene. RT-PCR indicated positive human α-galactosidase gene expression in all organs of positive human α-galacto-sidase transgenic F1 mice including heart, liver, kidney, lung, and spleen, the amount of Galα1,3Gal antigens on which was reduced largely. 58% of spleen cells from F1 mice were destroyed by comp-lement-mediated lysis compared with 24% of those from normal mice. Conclusions Human α-galactosidase gene and α1,2-fucosyltransferase gene effectively reduce the expression of Galα1,3Gal antigens on endothelial cell surface and confers resistance to human serum-mediated cytolysis. The expression of human α-galactosidase in mice can also eliminate the Galα1,3Gal antigens in most tissues and decrease the susceptibility of spleen cells to human serum-mediated cytolysis.

A Review on Regeneration in Cowpea （Vigna unguiculata L. Walp）

Vigna unguiculata L. Walp is a recalcitrant plant in terms of in vitro cell, tissue and organ differentiation, which makes it difficult to apply tissue-culture dependant approaches for obtaining stable genetic transformation in cowpea. Despite this, sporadic efforts have been made to develop regeneration systems in cowpea during the past 40 years. This review presents the considerable progress on cowpea regeneration （organogenesis and embryogenesis） and especially focuses on the regeneration mode of organogenesis, including highlights of the effect of genotypes, explants, medium and plant hormones used in tissue culture. The existing problems and the future research directions were also discussed.

Iron phthalocyanine-catalyzed radical phosphinoylazidation of alkenes:A facile synthesis of β-azido-phosphine oxide with a fast azido transfer step

Phosphinoylazidation of alkenes is a direct method to build nitrogen-and phosphorus-containing compounds from feed-stock chemicals.Notwithstanding the advances in other phosphinyl radical related difunctionalization of alkenes,catalytic phosphinoylazidation of alkenes has not yet been reported.Here,we describe the first iron-catalyzed intermolecular phosphinoylazidation of styrenes and unactivated alkenes.The method is practically useful and requires a relatively low loading of catalyst.Mechanistic studies confirmed the radical nature of the reaction and disclosed the unusually low activation energy 4.8 kcal/mol of radical azido group transfer from the azidyl iron(III)phthalocyanine species(PcFeulN3)to a benzylic radical.This work may help to clarify the mechanism of iron-catalyzed azidation,inspire other mechanism studies and spur further synthetic applications.

《赵熙书法》序

国家发扬文化,倡导艺事,搜集荣县赵熙先生之墨迹汇为一册。以予昔从杖履,得闻行迹,属予为序,义不敢辞。谨按先生姓赵氏,名熙,字尧生,别号香宋,以前清同治六年(一八六七年)生,由秀才而举人而进士。

再谈“书协轮值主席”

二○一三年第十期《书法》杂志『卷首语』中首次抛出了一个蛮有嚼头的概念『轮值主席』,其原话是：『可见书法官不简单,特有味道。既然这样不如弄个转盘,转到谁当,谁就过过瘾,挺好,这叫轮值主席,我想书法制度创新,可以在这方面动动脑筋。』

Synthesis of β-alkynyl α-amino acids via palladium-catalyzed alkynylation of unactivated C(sp^3)-H bonds

β-Di-substituted α-amino acids(AAs) contain adjacent carbon stereogenic centers and pose considerable synthetic challenge. Complementary to the conventional synthesis strategies based on the transformation of existing functional groups, we envisioned these molecules could be quickly accessed via selective functionalization of sp3 hybridized C-H bonds on the side chains of common α-AA precursors. We report a readily applicable method to prepare β-alkynyl α-amino acids via Pd-catalyzed diastereoselective C(sp3)-H alkynylation of common α-amino acids precursors with acetylene bromide.

Thermo-and pH-dual responsive inorganic-organic hybrid hydrogels with tunable luminescence

A thermo-and pH-dual responsive luminescent hydrogel was successfully constructed by coupling dysprosium-containing polyoxometalates Na_9 DyW_(10) O_(36)(DyW_(10)) with the ABA triblock copolymer, where the B block is PEO and the A block is the thermosensitive poly(methoxydi(ethylene glycol) methacrylate-co-N,N-dimethylaminoethyl methacrylate). The complex hybrid underwent a sol-gel phase transition above the lower critical solution temperature(LCST) of the A block. DyW_(10) was electrostatically encapsulated into the hydrophobic domain of the A block with enhanced photoluminescence. When temperature cooled down, the luminescence could be restored. By addition of acids to protonate the A block, and emission of DyW_(10) was simultaneously enhanced. Sensitivity of poly(N,N-dimethy laminoethyl methacrylate)(PDMAEMA) to pH also enabled the emission of DyW_(10)/copolymer hydrogel to be reversibly switched by alternating acid/base treatments.

Enantioselective synthesis of mixed 3,3’-bisindoles via a phosphine-catalyzed umpolung γ-addition of 3’-indolyl-3-oxindoles to allenoates

An enantioselective umpolung γ-addition reaction of 3’-indolyl-3-oxindoles to allenoates catalyzed by amino acid-derived bifunctional phosphine catalysts has been developed. A wide range of chiral mixed 3,3’-bisindole scaffolds containing an all-carbon quaternary stereogenic center were obtained in high yields and with excellent enantioselectivities. 3,3’-Bisindoles are valuable synthetic intermediates, the employment of which led to formal total syntheses of(+)-Chimonanthine,(+)-Folicanthine and(-)-Calycanthine, as well as facile creation of useful pyrrolidinoindoline core structure.

Thermo-responsive gelatin-functionalized PCL film surfaces for improvement of cell adhesion and intelligent recovery of gene-transfected cells

Efficient local gene transfection on a tissue scaffold is dependent on good cell-adhesion characteristics. In this work, the thermoresponsive gelatin-functionalized polycaprolactone(PCL) films were proposed for improvement of cell adhesion and intelligent recovery of gene-transfected cells. Functional copolymer brushes(PCL-g-P(NIPAAm-co-MAAS)) were first prepared via surface-initiated ATRP of N-isopropylacrylamide(NIPAAm) and methacrylic acid sodium salt(MAAS) from the initiatorfuncationalized PCL surfaces. The pendant carboxyl end-groups of the PCL-g-P(NIPAAm-co-MAAS) surface were subsequently coupled with gelatin via carbodiimide chemistry to produce the thermo-responsive gelatin-functionalized PCL surface. The thermo-responsive gelatin-functionalized PCL film surface can improve cell adhesion and proliferation above the LCST of P(NIPAAm) without destroying cell detachment properties at lower temperatures. The dense transfected cells can be recovered simply by lowering culture temperature. The thermo-responsive gelatin-functionalized PCL films are potentially useful as intelligent adhesion modifiers for directing cellular functions within tissue scaffolds.