The ligase PIAS1 restricts natural regulatory T cell differentiation by epigenetic repression

CD4(+)Foxp3(+) regulatory T (T(reg)) cells are important for maintaining immune tolerance. Understanding the molecular mechanism that regulates T(reg) differentiation will facilitate the development of effective therapeutic strategies against autoimmune diseases. We report here that the SUMO E3 ligase PIAS1 restricts the differentiation of natural T(reg) cells by maintaining a repressive chromatin state of the Foxp3 promoter. PIAS1 acts by binding to the Foxp3 promoter to recruit DNA methyltransferases and heterochromatin protein 1 for epigenetic modifications. Pias1 deletion caused promoter demethylation, reduced histone H3 methylation at Lys(9), and enhanced promoter accessibility. Consistently, Pias1(-/-) mice displayed an increased natural T(reg) cell population and were resistant to the development of experimental autoimmune encephalomyelitis. Our studies have identified an epigenetic mechanism that negatively regulates the differentiation of natural T(reg) cells.     

Activities of sodium and potassium ions in epithelial cells of small intestine

Intracellular molar Na(+) activity (a(Na)), measured with cation-selective glass microelectrodes, in epithelial cells of isolated bullfrog small intestine immersed at 26 degrees C in a sodium sulfate Ringer solution containing mannitol was 0.0144 +/- 0.0031 (average value plus or minus standard deviation). The corresponding K(+) activity (a(K)) was 0.0854 +/- 0.0060. Combination of these values with previous estimates of intracellular Na(+) and K(+) concentrations under identical conditions indicated that a substantial fraction of the cellular Na(+) is in an osmotically inactive state. When the cells were exposed to a Ringer solution in which 26 millimoles of mannitol per liter were replaced by 3-O-methyl glucose, highly significant decreases in a(K) and a(Na) were observed. The decrease in a(K) was proportionately larger than the corresponding decrease in a(Na).     

Active transport of potassium and chloride in an identifiable molluscan neuron

Direct measurements of intracellular K(+) and Cl(-)activities before and after blockage of cellular metabolic processes indicate that K(+) is actively transported inwardly and Cl(-)is actively transported outwardly from the giant cell of the abdominal ganglion of Aplysia. The rewarming of cells that have been cooled to 1 degrees +/- 1 degrees C causes K(+) to be taken up and Cl(-) to be extruded against electrochemical gradients.     

Lineage relationship analysis of RORgammat+ innate lymphoid cells

Lymphoid tissue-inducer (LTi) cells initiate the development of lymphoid tissues through the activation of local stromal cells in a process similar to inflammation. LTi cells express the nuclear hormone receptor RORγt, which also directs the expression of the proinflammatory cytokine interleukin-17 in T cells. We show here that LTi cells are part of a larger family of proinflammatory RORγt(+) innate lymphoid cells (ILCs) that differentiate from distinct fetal liver RORγt(+) precursors. The fate of RORγt(+) ILCs is determined by mouse age, and after birth, favors the generation of cells involved in intestinal homeostasis and defense. Contrary to RORγt(+) T cells, however, RORγt(+) ILCs develop in the absence of microbiota. Our study indicates that RORγt(+) ILCs evolve to preempt intestinal colonization by microbial symbionts.     

Sexual transmission and propagation of SIV and HIV in resting and activated CD4+ T cells

In sexual transmission of simian immunodeficiency virus, and early and later stages of human immunodeficiency virus-type 1 (HIV-1) infection, both viruses were found to replicate predominantly in CD4(+) T cells at the portal of entry and in lymphoid tissues. Infection was propagated not only in activated and proliferating T cells but also, surprisingly, in resting T cells. The infected proliferating cells correspond to the short-lived population that produces the bulk of HIV-1. Most of the HIV-1-infected resting T cells persisted after antiretroviral therapy. Latently and chronically infected cells that may be derived from this population pose challenges to eradicating infection and developing an effective vaccine.     

Interleukin-22 drives endogenous thymic regeneration in mice

Endogenous thymic regeneration is a crucial function that allows for renewal of immune competence after stress, infection, or immunodepletion. However, the mechanisms governing this regeneration remain poorly understood. We detail such a mechanism, centered on interleukin-22 (IL-22) and triggered by the depletion of CD4(+)CD8(+) double-positive thymocytes. Intrathymic levels of IL-22 were increased after thymic insult, and thymic recovery was impaired in IL-22-deficient mice. IL-22, which signaled through thymic epithelial cells and promoted their proliferation and survival, was up-regulated by radio-resistant RORγ(t)(+)CCR6(+)NKp46(-) lymphoid tissue inducer cells after thymic injury in an IL-23-dependent manner. Administration of IL-22 enhanced thymic recovery after total body irradiation. These studies reveal mechanisms of endogenous thymic repair and offer innovative regenerative strategies for improving immune competence.     

用Et花环法和酯酶染色法测定免疫前后猪血液中T淋巴细胞的比较试验

用总玫瑰花环(Et 花环)法和酯酶染色法分别测定了同窝7头幼龄猪,在用猪瘟疫苗免疫前测定了7份血样的 T 淋巴细胞(TL),又在免疫后测定了35份,结果表明:平均绝对值分别为6.06千/mm~3和5.48千/mm~3,平均百分率分别为37.33％和32.72％。Et 花环法测定的 TL 平均绝对值和平均百分率均高于酯酶染色法。两种方法所测定的42份血样的 TL 绝对值配对统计有显著差异(P<0.05)。作相关性检验呈非常显著的正线性相关(r=0.8323,P<0.001)。两种方法在免疫后测定的 TL 绝对值分别与免疫前测定的TL 数配对统计,均有显著差异。这种差异在 Et 花环法维持到免疫后的第24天,在酯酶染色法维持到免疫后的第48天。TL 绝对值的最高峰值均出现在免疫后的第8天。     

Different B cell populations mediate early and late memory during an endogenous immune response

Memory B cells formed in response to microbial antigens provide immunity to later infections; however, the inability to detect rare endogenous antigen-specific cells limits current understanding of this process. Using an antigen-based technique to enrich these cells, we found that immunization with a model protein generated B memory cells that expressed isotype-switched immunoglobulins (swIg) or retained IgM. The more numerous IgM(+) cells were longer lived than the swIg(+) cells. However, swIg(+) memory cells dominated the secondary response because of the capacity to become activated in the presence of neutralizing serum immunoglobulin. Thus, we propose that memory relies on swIg(+) cells until they disappear and serum immunoglobulin falls to a low level, in which case memory resides with durable IgM(+) reserves.     

Negro variant of glucose-6-phosphate dehydrogenase deficiency (A-) in man

Glucose-6-phosphate dehydrogenase in erythrocytes of the Negro type associated with enzyme deficiency (A(-)) was separated by chromatography on a carboxymethyl-Sephadex column from the electrophoretically indistinguishable Negro variant with normal enzyme activity (A(+)). Quantitative immunologic neutralization tests indicated that the A(-) enzyme had about the same enzymatic and serological activity as the A(+) and the normal (B(+)) enzymes. The enzyme activity of the A(-) variant in young erythrocytes was similar to that in young cells from normal individuals, although the activity of the A(-) variant in unfractionated red cells was 10 to 15 percent of normal. These data indicate that the basic defect in the variant enzyme (A(-)) is a structural mutation which causes more rapid degradation of the enzyme during erythrocyte aging.     

火炬松木材纤丝角和管胞长度的变异及其相关分析

在３处立地上各选５株１７．５ａ生火炬松木材，分别测定其管胞长度、纤丝角，并对２性状间的相关性进行了分析。结果：火炬松管胞长度由髓心向外递增，纤丝角由髓心向外递减，２性状在径向上呈显著的线性负相关；３处立地上林分内以及不同立地上林分间２性状均不呈显著的负相关，这说明株间木材管胞长度不能预测纤丝角。林木育种在评定优良种源、无性系，以及营林培育评价营林措施对木材材质的影响时，只能实测纤丝角。     

基于 SSR 标记的克氏原螯虾种质资源遗传多样性研究

选用10对克氏原螯虾微卫星引物对桐庐(TL)、太湖(TH)、湖北(HB)、江西(JX)、洪泽湖(HZH)、崇明(CM)、广西(GX)、海盐(HY)8个克氏原螯虾群体的遗传多样性状况和遗传结构进行研究。结果发现,8个克氏原螯虾群体的平均观测杂合度值为0.525 7~0.740 0,平均期望杂合度值在0.623 8~0.743 4之间,平均多态信息含量在0.420 9~0.684 0之间。其中广西(GX)群体遗传多样性最高,太湖(TH)群体遗传多样性最低。采用MEGA4.0计算各地理种群间的遗传距离,遗传距离最远的是崇明(CM)和江西(JX)群体,遗传距离最近的是湖北(HB)和太湖(TH)群体。结果显示,这8个地理种群资源遗传多样性较高。     

核桃楸种实性状变异规律及优良单株选择

对12个地点天然林中核桃楸果实超过100个的单株种实形态性状(包括种子质量、种仁质量、种壳厚、出仁率、三径均值等)进行测定与分析,结果表明:种子质量和种仁质量变异系数(分别为19.9%和20.4%)较大,种壳厚和出仁率变异系数(分别为13.58%和14.42%)中等,三径均值变异系数(8.42%)稍小。对各种源内的种仁质量与种子形态性状拟合,多数种源结果较理想。同时对种仁质量和出仁率分别与环境因子拟合,结果较理想(R2分别为90.71%和76.61%)。通过聚类分析和综合坐标法选出优良种源为三岔子、铁力、金山屯、亚布力,并通过综合坐标法选出各种源优良单株为BX1、BX3、BX13、BX30、BX25,DFH2、DFH9、DFH13、DFH26,DJC2、DJC5、DJC8、DJC13,JY7、JY9、JY14、JY21,LJ2、LJ7、LJ30、LJ8,WC2、WC3、WC4、WC7,HC1、HC7、HC16,HL1、HL10、HL15、HL26、HL14,JST1、JST4、JST24、JST27,YBL1、YBL5、YBL14、YBL16、YBL9,TL5、TL7、TL20、TL30、TL10,SC16、SC17、SC23、SC3、SC18。选择主要提高了出仁率、种仁质量和种壳厚这三个直接影响核桃楸品质的指标,各种源入选率在15%~25%,出仁率增益在5.81%~24.28%,种仁质量增益在5.19%~25.77%,种壳厚除东京城、临江、金山屯和亚布力外,其他种源增益不明显。     

湿地松木材管胞长度微纤丝角的变异及其相关性分析

研究了３个不同立地条件上１５株１７年生湿地松木材管胞长度,微纤丝角的变异及二性状间的相关性。结果表明立地指数对管胞长度,微纤丝角有着较大的影响。株内径向管胞长度由髓心向外递增,纤丝角递减,二性状间呈显著的线性负相关。     

A main group metal sandwich: five lithium cations jammed between two corannulene tetraanion decks

Lithium-coordinated polyaromatic anions such as tetrareduced corannulene, C(20)H(10)(4-) (1(4-)), are useful substrates to model and ultimately improve the graphitic electrodes in lithium-ion (Li(+)) batteries. Previous studies suggested that 1(4-) forms dimers encasing four Li(+) ions in solution. Here, we report a single-crystal x-ray diffraction analysis confirming the formation of a sandwich-type supramolecular aggregate with a high degree of alkali metal intercalation. In contrast to the prior model, our data reveal that five Li(+) ions are sandwiched between the two tetrareduced corannulene decks, and (7)Li nuclear magnetic resonance spectroscopy delineates a conserved structure in tetrahydrofuran solution. Remarkably, the sandwich is robust in both solution and solid states even in the presence of crown ethers that compete for Li(+) coordination. These results should help elucidate Li(+) intercalation motifs between curved carbon surfaces more broadly.     

Comparison of Growth and Development Patterns of Fenneropenaeus chinensis (Osbeck) Huanghai No.1 and the First Generation of Wild Population

[Objective] The aim was to estimate the developmental characteristics of Huanghai No.1 and the first generation of wild population in Fenneropenaeus chinensis for providing a reference for the development, feeding management and breeding. [Method] Four growth models were used to fit the growth patterns of 15 morphological traits. The squared multiple correlation coefficient (R2 ) of the Cubic growth model was higher than the other three models, so it was selected to investigate the growth pattern and age in month at inflexion. [Result] Ages in month at inflexion of body weight in Huanghai No.1 and the G1 population were 2.87 (body weight at inflexion was 14.98 g) and 4.05 (body weight at inflexion was 26.26 g), respectively. In addition, Ages in month at inflexion of morphological characters in Huanghai No.1 were from 0.51 to 3.07. CL had the most rapid growth rate, followed by AW, CH, AH, CW, BL, FL, AL5, AL3, AL4, TL, AL2, AL1, and AL6. Ages in month at inflexion in the G 1 population were from 2.38 to 3.08, except that of AL2, and the order of achieving the most rapid growth rate was AL2, AL1, AL3, AL4, CH, AL5, CW, FL, AH, AW, TL, CL, BL, and AL6, that delayed one month than that of Huanghai No.1 except AL2 and AL1. [Conclusion] The development of Huanghai No.1 cultivar was advanced for about one month compared to that of the G1 population.     

脱落酸(Abscisic acid, ABA)对映异构体的生物活性比较

 采用新方法精制脱落酸(ABA)异构体试样,改变以往靠光学离析法分离racemic型(SR)-(±)-ABA,提高了(S)-(+)-ABA与(R)-(-)-ABA两镜像体纯度。抑制生长试验和残留量分析结果表明:天然型(S)-(+)-ABA活性,显着高于非天然型(R)-(-)-ABA或(SR)-(±)-ABA活性。抑制莴苣种子发芽50%的活性强度(S)-(+)-ABA约是(R)-(-)-ABA的5倍,(SR)-(±)-ABA介于二者之间。抑制萝卜下胚轴生长试验,最显着有效期2～6天,(6天后差异渐小,8日甚微),生理作用期约为一周,(S)-(+)-ABA活性是(R)-(-)-ABA的3.6倍。差异原因可能是两异构体分子立体结构不同所致。     

Crystal Structure of the Polymer Electrolyte Poly(ethylene oxide)3:LiCF3SO3

Ionically conducting polymers (polymer electrolytes) are under intensive investigation because they form the basis of all solid-state lithium batteries, fuel cells, and electrochromic display devices, as well as being highly novel electrolytes. Little is known about the structures of the many crystalline complexes that form between poly(ethylene oxide) and a wide range of salts. The crystal structure is reported of the archetypal polymer electrolyte poly(ethylene oxide)(3):LiCF(3)SO(3), which has been determined from powder x-ray diffraction data. The poly(ethylene oxide) (PEO) chain adopts a helical conformation parallel to the crystallographic b axis. The Li(+) cation is coordinated by five oxygen atoms-three ether oxygens and one from each of two adjacent CF(3)SO(3)(-) groups. Each CF(3)SO(3)(-) in turn bridges two Li(+) ions to form chains running parallel to and intertwined with the PEO chain. There are no interchain links between PEO chains, and the electrolyte can be regarded as an infinite columnar coordination complex.     

改良耕层土壤中苯胺的吸附动力学

研究有机改良土壤对污染物的动力学吸附特征,有助于深入了解其对污染物的吸附机制。以十六烷基三甲基溴化铵单一改良(CB)和十六烷基三甲基溴化铵+十二烷基磺酸钠混合改良(CS)塿土耕层土样,采用批处理法通过不同的速度参数研究了改良土壤对苯胺的吸附动力学特征,并与苯酚对比探讨改良土样对有机污染物吸附的动力学机制。结果表明,塿土耕层土样的有机改良能够显著加快对苯胺的吸附速度,苯胺的吸附反应呈现快速反应和慢速反应两个阶段,且以快速吸附反应为主。总体上耕层土样Vt、V0.5、Vf的大小顺序均为100CB120CS(≈)50CBCK。随温度升高和苯胺添加浓度增大,苯胺吸附速度增大,苯胺、苯酚的吸附动力学特征在改良土样上具有良好的相似性,从而证实有机污染物以分子状态存在导致的单一疏水吸附是改良土样吸附的决定机制。     

Selective stimulation of one of the mechanisms for genetic recombination of bacteriophage S13

In certain recombination-deficient (Rec(-)) bacterial strains genetic recombination of bacteriophage S13 is reduced, but the existence of some residual recombination has suggested that there is a secondary mechanism of phage recombination that is still functioning. In these Rec(-)strains it is found that there is no stimulation of recombination by irradiation of the parental phage with ultraviolet light, in contrast to the large increase found when irradiated phage particles infect a Rec(+) host. This selective stimulation of phage recombination in the Rec(+) but not in the Rec(-) strains supports the view that the phage uses at least two mechanisms of genetic recombination.     

Lineage tracing reveals Lgr5+ stem cell activity in mouse intestinal adenomas

The concept that tumors are maintained by dedicated stem cells, the so-called cancer stem cell hypothesis, has attracted great interest but remains controversial. Studying mouse models, we provide direct, functional evidence for the presence of stem cell activity within primary intestinal adenomas, a precursor to intestinal cancer. By "lineage retracing" using the multicolor Cre-reporter R26R-Confetti, we demonstrate that the crypt stem cell marker Lgr5 (leucine-rich repeat-containing heterotrimeric guanine nucleotide-binding protein-coupled receptor 5) also marks a subpopulation of adenoma cells that fuel the growth of established intestinal adenomas. These Lgr5(+) cells, which represent about 5 to 10% of the cells in the adenomas, generate additional Lgr5(+) cells as well as all other adenoma cell types. The Lgr5(+) cells are intermingled with Paneth cells near the adenoma base, a pattern reminiscent of the architecture of the normal crypt niche.