Identification of Chromosomes from Multiple Rice Genomes Using a Universal Molecular Cytogenetic Marker System

To develop reliable techniques for chromosome identification is critical for cytogenetic research, especially for genomes with a large number and smaller-sized chromosomes. An efficient approach using bacterial artificial chromosome （BAC） clones as molecular cytological markers has been developed for many organisms. Herein, we present a set of chromosomal arm-specific molecular cytological markers derived from the gene-enriched regions of the sequenced rice genome. All these markers are able to generate very strong signals on the pachytene chromosomes of Oryza sativa L. （AA genome） when used as fluorescence in situ hybridization （FISH） probes. We further probed those markers to the pachytene chromosomes of O. punctata （BB genome） and O. officinalis （CC genome） and also got very strong signals on the relevant pachytene chromosomes. The signal position of each marker on the related chromosomes from the three different rice genomes was pretty much stable, which enabled us to identify different chromosomes among various rice genomes. We also constructed the karyotype for both O. punctata and O. officinalis with the BB and CC genomes, respectively, by analysis of 10 pachytene cells anchored by these chromosomal arm-specific markers.     

小三江平原湿地东方白鹳（Ciconia boyciana）生境丧失的生态后果

采用生境套娃方法反映水禽——东方白鹳生境需求的层级系统基础上,利用GIS技术建立定量化分析模型,深入探讨了小三江平原生境丧失对东方白鹳生境空间分布的影响。结果显示：与初始状态1954年相比,东方白鹳繁殖生境丧失了81.9％,平均斑块面积缩小了88％;同时,生境面积的丧失是伴随生境破碎化过程发生的。1983之后生境破碎化明显加剧,到2005年生境连通度显著降低,生境处于高度破碎化状态。研究表明,生境丧失对东方白鹳繁殖生境的影响不仅取决于关键生境要素的变化,生境空间异质性改变更为重要。     

Effects of different irrigation modes on winter wheat grain yield and water- and nitrogen use efficiency

Taking the widely planted winter wheat cultivar Tainong 18 as test material, a field experiment was conducted to study the effects of different irrigation modes on the winter wheat grain yield and water- and nitrogen use efficiency in drier year (2009-2010) in Tai' an City of Shandong Province, China. Five treatments were installed, i. e., irrigation before sowing (CK), irrigation before sowing and at jointing stage (W1), irrigation before sowing and at jointing stages and at over-wintering stage with alternative irrigation at milking stage (W2), irrigation before sowing and at jointing and flowering stages (optimized traditional irrigation mode, W3), and irrigation before sowing and at over-wintering, jointing, and milking stages (traditional irrigation mode, W4). The irrigation amount was 600 m3 hm(-2) one time. Under the condition of 119.7 mm precipitation in the winter wheat growth season, no significant difference was observed in the grain yield between treatments W2 and W4, but the water use efficiency was significantly higher in W2 than in W4. Comparing with treatment W3, treatments W2 and W4 had obviously higher grain yield, but the water use efficiency had no significant difference. The partial factor productivity from N fertilization was the highest in W2 and W4, and the NO3(-)-N accumulation amount in 0-100 cm soil layer at harvest was significantly higher in W2 than in W3 and W4, suggesting that W2 could reduce NO3(-)-N leaching loss. Under the conditions of our experiment, irrigation before sowing and jointing stages and at over-wintering stage with alternative irrigation at milking stage was the optimal irrigation mode in considering both the grain yield and the water- and nitrogen use efficiency.     

天然来源抗肿瘤化合物作用于MAPK通路的机制

天然来源抗肿瘤活性产物是抗肿瘤药物先导化合物的重要资源。促分裂原活化蛋白激酶(MAPK)通路是细胞内重要的信号转导系统,可以调节细胞的生长、凋亡、黏附、迁移等过程,继而影响肿瘤的发生、发展、侵袭、转移,是潜在的抗肿瘤药物作用靶点之一。本文将对天然来源化合物作用于MAPK信号通路的靶点分子及生物效应进行阐述,为肿瘤的化学预防及治疗提供启发。     

Catalytic properties of MGAT3, a putative triacylgycerol synthase

Acyl-coenzyme A:monoacylglycerol acyltransferase 3 (MGAT3) is a member of the MGAT family of enzymes that catalyze the synthesis of diacylglycerol (DAG) from monoacylglycerol (MAG), a committed step in dietary fat absorption. Although named after the initial identification of its MGAT activity, MGAT3 shares higher sequence homology with acyl-coenzyme A:diacylglycerol acyltransferase 2 (DGAT2) than with other MGAT enzymes, suggesting that MGAT3 may also possess significant DGAT activity. This study compared the catalytic properties of MGAT3 with those of MGAT1 and MGAT2 enzymes using both MAG and DAG as substrates. Our results showed that in addition to the expected MGAT activity, the recombinant MGAT3 enzyme expressed in Sf-9 insect cells displayed a strong DGAT activity relative to that of MGAT1 and MGAT2 enzymes in the order MGAT3 > MGAT1 > MGAT2. In contrast, none of the three MGAT enzymes recognized biotinylated acyl-CoA or MAG as a substrate. Although MGAT3 possesses full DGAT activity, it differs from DGAT1 in catalytic properties and subcellular localization. The MGAT3 activity was sensitive to inhibition by the presence of 1% CHAPS, whereas DGAT1 activity was stimulated by the detergent. Consistent with high sequence homology with DGAT2, the MGAT3 enzyme demonstrated a similar subcellular distribution pattern to that of DGAT2, but not DGAT1, when expressed in COS-7 cells. Our data suggest that MGAT3 functions as a novel triacylglycerol (TAG) synthase that catalyzes efficiently the two consecutive acylation steps in TAG synthesis.     

Resolution of N-(2-ethyl-6-methylphenyl) alanine catalyzed by Lipase B from Candida antarctica

A biotransformation process has been developed for the production of (S)-N-(2-ethyl-6-methylphenyl) alanine by enantioselective hydrolysis of racemic methyl ester in the presence of Candida antarctica lipase B (CAL-B). However, the enantioselectivity of CAL-B towards the resolution is not high enough to obtain enantiomerically pure product. In order to improve the enantioselectivity of the enzyme, the effects of surfactants on CAL-B-catalyzed hydrolysis were tested. The results suggest that surfactants can influence the microenvironment of the enzyme, and the addition of Tween-80, in particular, to the reaction medium markedly enhanced the selectivity of CAL-B towards the substrate used, with the enantiomeric ratio (E-value) increasing from 11.3 to 60.1.     

Chromatographic and electrophoretic methods for pharmaceutically active compounds in Rhododendron dauricum

In this review, chemical constituents present in Rhododendron dauricum L. were briefly surveyed, and the methods of pretreatment of this plant prior to analysis were also summarized. The analysis methods reported for determining pharmaceutically active compounds in R. dauricum L. include gas chromatography with mass spectrscopy, thin layer chromatography (TLC), high performance liquid chromatography (HPLC) and capillary electrophoresis (CE). In addition, both advantages and disadvantages of the above methods were mentioned.     

盾叶薯蓣营养器官薯蓣皂甙元含量的动态变化

利用高效液相色谱(HPLC)法对盾叶薯蓣营养器官特别是根状茎中薯蓣皂甙元含量的动态变化、品种之间的差异以及雌雄株之间的差异进行了研究。结果表明：实生苗根状茎中薯蓣皂甙元的含量,2年生高于1年生;根茎营养繁殖的2年生根状茎中皂甙元的含量高于1年生的含量;花叶品种的含量高于绿叶品种的含量;雄株的含量比雌株的含量高。在地上的缠绕茎和叶中没有检测到薯蓣皂甙元。由根茎繁殖的1年生根状茎前期皂甙元含量增加缓慢,后期增加较快;2年生根状茎盛花期含量最高,开花后期含量最低,随后含量逐渐增加。为此应在花叶品种中选择产量高、抗性强的品种作为栽培品种。合适的采挖期仍以地上缠绕茎枯萎期为宜。     

The γ134.5 Protein of Herpes Simplex Virus 1 Is Required To Interfere with Dendritic Cell Maturation during Productive Infection

The γ₁34.5 protein of herpes simplex virus 1 is an essential factor for viral virulence. In infected cells, this viral protein prevents the translation arrest mediated by double-stranded RNA-dependent protein kinase R. Additionally, it associates with and inhibits TANK-binding kinase 1, an essential component of Toll-like receptor-dependent and -independent pathways that activate interferon regulatory factor 3 and cytokine expression. Here, we show that γ₁34.5 is required to block the maturation of conventional dendritic cells (DCs) that initiate adaptive immune responses. Unlike wild-type virus, the γ₁34.5 null mutant stimulates the expression of CD86, major histocompatibility complex class II (MHC-II), and cytokines such as alpha/beta interferon in immature DCs. Viral replication in DCs inversely correlates with interferon production. These phenotypes are also mirrored in a mouse ocular infection model. Further, DCs infected with the γ₁34.5 null mutant effectively activate naïve T cells whereas DCs infected with wild-type virus fail to do so. Type I interferon-neutralizing antibodies partially reverse virus-induced upregulation of CD86 and MHC-II, suggesting that γ₁34.5 acts through interferon-dependent and -independent mechanisms. These data indicate that γ₁34.5 is involved in the impairment of innate immunity by inhibiting both type I interferon production and DC maturation, leading to defective T-cell activation.Herpes simplex virus 1 (HSV-1) is a human pathogen responsible for localized mucocutaneous lesions and encephalitis (51). Following primary infection, HSV-1 establishes a latent or lytic infection in which the virus interacts with host cells, which include dendritic cells (DCs), required to initiate adaptive immune responses (36). Immature DCs, which reside in almost all peripheral tissues, are able to capture and process viral antigens (15). In this process, DCs migrate to lymph nodes, where they mature and present antigens to T cells. Mature DCs display high levels of major histocompatibility complex class II (MHC-II) and costimulatory molecules such as CD40, CD80, and CD86. Additionally, DCs release proinflammatory cytokines such as interleukin-12 (IL-12), tumor necrosis factor alpha, alpha interferon (IFN-α), and IFN-β, which promote DC maturation and activation. An important feature of functional DCs is to activate naïve T cells, and myeloid submucosal and lymph node resident DCs are responsible for HSV-specific T-cell activation (2, 45, 52). Moreover, DCs play a direct role in innate antiviral immunity by secreting type I IFN.HSV-1 is capable of infecting both immature and mature DCs (20, 24, 34, 38, 42). A previous study suggested that HSV entry into DCs requires viral receptors HVEM and nectin-2 (42). Upon HSV infection, plasmacytoid DCs detect viral genome through Toll-like receptor 9 (TLR9) and produce high levels of IFN-α (16, 23, 30, 40). In contrast, myeloid DCs, which are major antigen-presenting cells, recognize viral components through distinct pathways, independently of TLR9 (16, 36, 40). It has been suggested previously that HSV proteins or RNA intermediates produced during viral replication trigger myeloid DCs (16, 40). Indeed, a protein complex that consists of HSV glycoproteins B, D, H, and L stimulates the expression of CD40, CD83, CD86, and cytokines in myeloid DCs (41). Hence, DCs sense HSV through TLR-dependent and -independent mechanisms (16, 40, 41). Nevertheless, HSV replication compromises DC functions and subsequent T-cell activation (3, 20, 24, 42). HSV-1 interaction with immature DCs results in the downregulation of costimulatory molecules and cytokines (20, 34, 38, 42). While HSV-2 induces rapid apoptosis, HSV-1 does so with a delayed kinetics in human DCs (4, 20, 38). HSV-1 is also reported to interfere with functions of mature DCs (24, 39). Upon infection, HSV-1 induces the degradation of CD83 but not CD80 or CD86 in mature DCs (24, 25). Additionally, HSV-1 reduces levels of the chemokine receptors CCR7 and CXCR4 on mature DCs and subsequently impairs DC migration to the respective chemokine ligands CCL19 and CXCL12 (39).Although HSV infection impairs DC functions, viral components responsible for this impairment have not been thoroughly investigated. It has been suggested previously that the virion host shut-off protein (vhs) of HSV-1 contributes partially to the viral block of DC activation (43). This activity is thought to stem from the ability of vhs to destabilize host mRNA. Emerging evidence suggests that ICP0 perturbs the function of mature DCs, where it mediates CD83 degradation via cellular proteasomes (25). Findings from related studies show that ICP0 inhibits the induction of IFN-stimulated genes mediated by IFN regulatory factor 3 (IRF3) or IRF7 in other cell types (11, 27, 32, 33). However, the link of ICP0 activities to DC maturation remains to be established. Recently, we found that γ₁34.5, an HSV virulence factor, associates with and inhibits TANK-binding kinase 1 (TBK1), an essential component of TLR-dependent and -independent pathways that activates IRF3 and cytokine expression (49). Interestingly, an HSV mutant lacking γ₁34.5 stimulates MHC-II surface expression in glioblastoma cells (47). These observations raise the hypothesis that γ₁34.5 may modulate DC maturation during HSV infection.In this study, we report that γ₁34.5 is required to perturb DC maturation during HSV infection, leading to impaired T-cell activation. Wild-type virus, but not the γ₁34.5 null mutant, suppresses the expression of costimulatory molecules as well as cytokines in DCs. We provide evidence that the viral block of DC maturation is associated with reduced IFN-α/β secretion. Furthermore, the expression of γ₁34.5 inhibits DC-mediated allogeneic T-cell activation and IFN-γ production. IFN-neutralizing antibodies partially reverse DC maturation induced by the γ₁34.5 null mutant. These results shed light on the role of γ₁34.5 relevant to DC maturation and T-cell responses in HSV infection.     

Influence of ammonium and nitrate supply on growth,nitrate reductase activity and N-use efficiency in a natural hybrid pine and its parents

Aims Selection of tree species with a high capacity to assimilate N and efficiently utilize N resources would facilitate the success of initial tree seedling establishment in infertile soils. The preference for N forms was tested using three pine species (Pinus densata, Pinus tabuliformis and Pinus yunnanensis). Pinus densata is a natural diploid hybrid between P. tabuliformis and P. yunnanensis .Methods Seedlings of three pine species were supplied with nitrate-N, ammonium-N (at two different pH regimes) or combined ammonium and nitrate as a nitrogen source in perlite culture in a controlled environment.Important findings Seedlings of P. densata had higher total biomass and net photosynthesis when supplied with nitrate-N and ammonium nitrate than with ammonium-N. In parental species, total biomass and net photosynthesis for P. yunnanensis seedlings was higher in ammonium-N than in nitrate-N, whereas the other parental species P. tabuliformis had the highest total biomass among species for all treatments except ammonium with CaCO 3. Most morphological traits in P. densata seedlings were intermediate between its two parental species. However, N-use efficiency and photosynthetic N-use efficiency of P. densata significantly exceeded both parents when supplied with nitrate-N and ammonium nitrate. The results suggested that the diploid hybrid tree species P. densata has a preference for nitrate and is not well adapted to ammonium-N as a sole nitrogen source regardless of the growth medium pH. Based on changes in environmental conditions, such as predicted future temperature increases in high altitude areas associated with climate change, P. densata is likely to be increasingly competitive and have wide adaptation in high altitude regions.