Shared Escovopsis parasites between leaf-cutting and non-leaf-cutting ants in the higher attine fungus-growing ant symbiosis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

几种作物非叶器官结构和功能的研究

本论文以小麦、水稻等几种重要经济作物为材料，应用透射电镜、扫描电镜、激光共聚焦显微镜以及氧电极，低温荧光等生理技术手段，对作物非叶器官的结构和主要生理特性进行了较全面和系统的研究。其中，比较分析了非叶器官叶绿体超微结构的差异，测量了非叶器官的放氧和低温荧光等生理指标，尝试从结构与功能相结合的角度，探讨非叶器官在提高作物产量中所起的重要作用。 首先以不同品种的小麦为实验材料，对其主要非叶器官－茎秆，从解剖结构、木质素含量、以及抗倒伏的力学特性等方面做了详细的比较研究。结果表明：高产小麦品种茎秆的秆壁厚度、茎截面积、机械组织厚度及细胞层数、维管束与其韧皮部的截面积等，均明显优于一般小麦品种。在茎秆薄壁组织细胞、机械组织细胞（厚壁组织细胞）和维管束的木质素含量上，高产品种也显著高于对照品种。另外，通过分析证明，小麦植株抗倒伏的能力与其茎秆高度、直径和髓腔直径等均有密切关系。因此，在超高产小麦品种的选育上，重视外源基因的引进，改进茎秆的结构特性及提高其木质素含量，可能是一个重要的选育方向。 气孔是植物器官吸收CO2 和放出O2 的主要通道，对光合作用的强弱有着决定性的作用。因此，对非叶器官表面气孔的研究显得尤为重要。通过对几种作物非叶器官气孔频度、气孔大小和气孔指数的研究，结果发现，非叶器官的气孔频度均较对应功能叶低;而气孔大小和气孔指数则变化较大。另外，本文还着重讨论了非叶器官气孔频度对作物光合作用的影响，并提出了在非叶器官中可能存在与此相适应的未知的光合类型 叶绿体是作物进行光合作用的场所，通过对小麦、水稻非叶器官及功能叶叶绿体超微结构的比较研究，发现非叶器官单个光合细胞中叶绿体的数量较少，体积也较小。其中小麦芒和颖片有发育较好的叶绿体结构，其基粒数可达普通叶的水平，但比旗叶少;外稃和穗轴都有完整的基粒跺叠，只是跺叠的数量较少;而内稃基粒少，基粒内囊体跺叠不整齐。随着小麦芒的衰老过程，其中叶绿体的数量也随之减少，并且这种减少的趋势在旗叶中先发生。非叶器官中叶绿体超微结构的这种变化和差异，暗示着非叶器官可能在作物的不同发育时期，对籽粒有重要作用。 通过对非叶器官和功能叶光合特性的比较研究，发现不同种作物非叶器官具有与功能叶不同的光合特性。在436nm 激发光下，非叶器官的F686／F734 明显高于旗叶;若以放氧为标准，比较功能叶和非叶器官的光合活性，发现以叶绿素为单位，非叶器官的放氧速率与旗叶相当，或甚至高于旗叶;以单穗为单位，最高可相当于旗叶的28％。另外，比较不同发育时期芒和旗叶的放氧速率，发现芒在作物的衰老后期，仍保持较高的光合活性。

大豆（Glycine max (L)Merr.）叶片和非叶器官光合特性探讨

本论文由三部分组成，一、大豆高产品种黑农40与低产品种黑农37不同发育时期叶片光合功能的比较研究。二、大豆非叶器官豆荚的光合特性。三、不同大豆品种叶片和非叶器官光合特性的比较分析。 一、 黑农40和黑农37不同发育时期叶片的光合特性。 以不同产量水平的东北大豆黑农40和对照品种黑农37为试验材料，研究了从幼苗期到衰老期五个不同发育时期叶片光合作用特性的变化。尤其是比较系统地研究了C4途径的表达，并通过相关分析，发现C4途径酶的活性与大豆的光合效率及其产量密切相关。主要研究结果如下： 1．测定不同发育时期大豆叶片净光合速率、DCIP光还原活力和1,5-二磷酸核酮糖羧化酶(RuBPcase)活力，结果表明，黑农40和黑农37叶片净光合速率均在初荚期达到最高值，而且不同发育时期的黑农40叶片光合能力均强于黑农37。 2．随着大豆叶片的发育和衰老，其叶绿素、类胡萝卜素的含量及Chla/b比值有一个逐渐升高，而后降低的过程。在同一发育时期，高产高光效品种黑农40光合色素含量均高于黑农37，有助于黑农40捕获更多的光能供光合作用所利用。 3．叶绿体吸收光谱及四阶导数光谱表明在整个生育期内以初荚期叶片对光能的吸收能力最强;而每一个发育时期黑农40叶片对光能吸收的能力均比黑农37高。荧光动力学参数表明，高产大豆黑农40叶片PSII活性(Fv/Fo)，光化学猝灭系数(qP)及PSII总的光化学量子产量也均高于对照品种黑农37的相应值：而黑农40的非光化学猝灭系数(qN)低于黑农37。说明高产大豆叶片具有与产量潜力相关的较高光能吸收和原初转化能力。通过对叶片及其叶绿体低温(77K)荧光发射光谱特性的分析表明，黑农40叶绿体对两个光系统之间激发能的调节能力优于黑农37。总之，黑农40对光能的吸收、传递和转化能力高于黑农37，从而能为碳同化提供更多能量。 4．通过研究苗期、开花期、初荚期、鼓粒期和衰老期等发育阶段的黑农40和黑农37叶片中磷酸烯醇式丙酮酸羧化酶(PEPCase)、NADP-苹果酸脱氢酶(NADP-MDH)、NADP-苹果酸酶(NADP-ME)、丙酮酸磷酸双激酶(PPDK)等C4途径的关键酶的活性变化，结合同位素14CO2喂饲试验，证明两种大豆叶片均含有C4途径四种关键酶，其原初产物含有有限的有机酸，说明有C4循环存在;而从PEPCase/RuBPcase的比值看，C4途径的酶在黑农40叶片中表达较高。通过相关分析，我们发现Pn与PSII光化学活性，RuBPCase及C4酶活性密切相关。这些结果还暗示有可能通过检测C4途径酶的表达水平及比例，筛选出具有高产潜力的大豆种质。 二、大豆非叶器官豆荚的光合特性。 通过对大豆非叶器官豆荚光合特性的研究，结果表明大豆豆荚的光合能力在鼓粒期达到最高值。通过叶绿体吸收光谱、荧光动力学和低温荧光等测定技术，我们发现鼓粒期的豆荚对光能的吸收、传递和转化有更高的能力;在鼓粒期不同品种的豆荚色素的含量也较高，从而有利于捕获更多的光能，供光合作用利用。DCIP光还原活力的测定结果表明鼓粒期豆荚也具有较高光合能力。 通过对大豆的初荚期、鼓粒期和衰老期豆荚RuBPCase和四种C4途径酶活性的研究，不仅证明非叶器官中有高活性的C4途径酶和存在有限的C4途径，而且鼓粒期豆荚有较高的碳同化效率。 三、不同大豆叶片和非叶器官光合特性的比较分析。 对三种大豆叶片、豆荚、种皮和子叶的色素含量和Chla/b进行测定，利用光谱技术、荧光技术及RuBPCase活性的测定，分析了大豆不同器官的光合特性。试验结果证明，非叶器官具有与叶器官相似的光合性能。与叶片比较，表明在非叶器官中具有非常高的C4酶活性。有利于补偿叶片开始衰老光合作用衰退的不足，因此非叶器官的这些光合特性有助于增加大豆光合产物的积累。

Analysis of the barley bract suppression gene Trd1

A typical barley (Hordeum vulgare) floret consists of reproductive organs three stamens and a pistil, and non-reproductive organs-lodicules and two floral bracts, abaxial called 'lemma' and adaxial 'palea'. The floret is subtended by two additional bracts called outer or empty glumes. Together these organs form the basic structural unit of the grass inflorescence, a spikelet. There are commonly three spikelets at each rachis (floral stem of the barley spike) node, one central and two lateral spikelets. Rare naturally occurring or induced phenotypic variants that contain a third bract subtending the central spikelets have been described in barley. The gene responsible for this phenotype was called the THIRD OUTER GLUME1 (Trd1). The Trd1 mutants fail to suppress bract growth and as a result produce leaf-like structures that subtend each rachis node in the basal portion of the spike. Also, floral development at the collar is not always suppressed. In rice and maize, recessive mutations in NECK LEAF1 (Nl1) and TASSEL SHEATH1 (Tsh1) genes, respectively, have been shown to be responsible for orthologous phenotypes. Fine mapping of the trd1 phenotype in an F-3 recombinant population enabled us to position on the long arm of chromosome 1H to a 10 cM region. We anchored this to a conserved syntenic region on rice chromosome Os05 and selected a set of candidate genes for validation by resequencing PCR amplicons from a series of independent mutant alleles. This analysis revealed that a GATA transcription factor, recently proposed to be Trd1, contained mutations in 10 out of 14 independent trd1 mutant alleles that would generate non-functional TRD1 proteins. Together with genetic linkage data, we confirm the identity of Trd1 as the GATA transcription factor ortholog of rice Nl1 and maize Tsh1 genes.

Importance of anatomical leaf features for characterization of three species of Mapania (Mapanioideae, Cyperaceae) from the Amazon Forest, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Neurally adjusted ventilatory assist decreases ventilator-induced lung injury and non-pulmonary organ dysfunction in rabbits with acute lung injury

OBJECTIVE: To determine if neurally adjusted ventilatory assist (NAVA) that delivers pressure in proportion to diaphragm electrical activity is as protective to acutely injured lungs (ALI) and non-pulmonary organs as volume controlled (VC), low tidal volume (Vt), high positive end-expiratory pressure (PEEP) ventilation. DESIGN: Prospective, randomized, laboratory animal study. SUBJECTS: Twenty-seven male New Zealand white rabbits. INTERVENTIONS: Anesthetized rabbits with hydrochloric acid-induced ALI were randomized (n = 9 per group) to 5.5 h NAVA (non-paralyzed), VC (paralyzed; Vt 6-ml/kg), or VC (paralyzed; Vt 15-ml/kg). PEEP was adjusted to hemodynamic goals in NAVA and VC6-ml/kg, and was 1 cmH2O in VC15-ml/kg. MEASUREMENTS AND MAIN RESULTS: PaO2/FiO2; lung wet-to-dry ratio; lung histology; interleukin-8 (IL-8) concentrations in broncho-alveolar-lavage (BAL) fluid, plasma, and non-pulmonary organs; plasminogen activator inhibitor type-1 and tissue factor in BAL fluid and plasma; non-pulmonary organ apoptosis rate; creatinine clearance; echocardiography. PEEP was similar in NAVA and VC6-ml/kg. During NAVA, Vt was lower (3.1 +/- 0.9 ml/kg), whereas PaO2/ FiO2, respiratory rate, and PaCO2 were higher compared to VC6-ml/kg (p<0.05 for all). Variables assessing ventilator-induced lung injury (VILI), IL-8 levels, non-pulmonary organ apoptosis rate, and kidney as well as cardiac performance were similar in NAVA compared to VC6-ml/kg. VILI and non-pulmonary organ dysfunction was attenuated in both groups compared to VC15-ml/kg. CONCLUSIONS: In anesthetized rabbits with early experimental ALI, NAVA is as effective as VC6-ml/kg in preventing VILI, in attenuating excessive systemic and remote organ inflammation, and in preserving cardiac and kidney function.

Measurement of FSH in the ovarian tissue by radioimmunoassay: Correlation to serum FSH levels and follicular development in the hamster

A method is described for monitoring the concentration of endogenous receptor-bound gonadotropin in the ovarian tissue. This involved development of a radioimmunoassay procedure, the validity of which for measuring all of the tissue-bound hormone has been established. The specificity of the method of measurement was indicated by the fact that high levels of FSH could be measured only in target tissue such as follicles, while non-target organs showed little FSH. Using this method, the amount of FSH in the non-luteal ovarian tissue of the hamster at different stages of the estrous cycle was quantitated and compared with serum FSH levels found at these times. No correlation could be found between serum and tissue FSH levels at all times. On the morning of estrus, for example, when the serum level of FSH was high, the ovarian concentration was low, and on the evening of diestrus-2 the ovary exhibited high concentration of FSH, despite the serum FSH concentration being low at this time. The highest concentration of FSH in the ovary during the cycle was found on the evening of proestrus. Although a large amount of this was found in the Graafian follicles, a considerable amount could still be found in the �growing� follicles. Ovarian FSH concentration could be considered to be a reflection of FSH receptor content, since preventing the development of FSH receptors by blocking initiation of follicular development during the cycle resulted in a decrease in the concentration of FSH in the ovary. The high concentration of FSH in the ovary seen on the evening of diestrus-2 was not influenced either by varying the concentration of estrogen or by neutralization of LH. Neutralization of FSH on diestrus-2, on the other hand, caused a drastic reduction in the ovarian LH concentration on the next day (i.e. at proestrus), thus suggesting the importance of FSH in the induction of LH receptors.

I.小麦非叶器官碳酸酐酶活性与定位分析II.镉毒害导致芦苇胚性细胞死亡的激素调控研究

第一部分： 通过生理测定和化学染色分析了冬小麦品种小堰54和京411的叶片和非叶片组织的碳酸酐 酶活性。叶片碳酸酐酶活性(CA)在挑旗时期达到最大值，之后减少到最小，而在饱粒期又呈 增加趋势。从灌浆期到饱粒期，颖片和内稃的CA活性均减少，而外稃和种皮的CA活性均增加。在饱粒期，小堰54的叶片、颖片、外稃和种皮CA活性均高于京411。组织化学染色表明，CA主要分布在旗叶的叶肉细胞叶绿体中，也分布在非叶片组织颖片、外稃和内稃的叶肉和维管束鞘细胞的胞质中。这些结果表明，小麦非叶组织叶肉和维管束鞘细胞的胞质中的CA可能对饱粒期冬小麦的C4光合途径起作用。饱粒期小堰54的C02传递到Rubisco酶速率和抗旱性较京411高。 第二部分： 以继代培养的芦苇胚性细胞为材料，利用台盼兰拒染法检测了悬浮细胞死亡过程，并利用石蜡切片法及苏木精染色法观察了不同浓度镉对芦苇细胞的毒害作用。1000μM的CdCl2迅速导致芦苇悬浮细胞死亡，200μM的CdClz在接种后第5天引起悬浮细胞死亡，100μM的CdCl2在接种后第7天引起悬浮细胞死亡，≤50μM的CdClz在接种后7天不引起悬浮细胞死亡。同时对不同浓度镉处理的芦苇胚性细胞的内源植物激素和可溶性蛋白质进行分析，≤50μM的镉浓度显著地降低胚性细胞内IAA、ZR、GA3和GA4的含量，却提高ABA的含量，抑制可溶性蛋白质的合成：≥100μM的镉浓度显著地提高IAA、ZR、GA3和GA4的含量，却降低ABA的含量，促进可溶性蛋白质的合成。这些结果表明，镉的毒害至少包括镉浓度决定的两种细胞死亡机制，高浓度的镉(1000μM)引起的细胞死亡应当为坏死，而100μM的镉引起植物悬浮细胞发生程序性死亡。在较高浓度(≥100μM)的镉处理下，芦苇细胞内内源IAA、ZR、GA3和GA4的浓度较高，可能调控可溶性蛋白质的合成而促进细胞发生程序化死亡。

CO2浓度升高对红桦幼苗生理与生长的影响

大气CO2浓度的增加已经成为不可争议的事实。预计本世纪末大气CO2浓度将增加到约700µmol mol-1。森林年光合产量约占陆地生态系统年光合产量的70%。森林树木是一个巨大的生物碳库，约占全球陆地生物碳库的85%。森林树木对CO2的固定潜力是缓解由大气CO2浓度升高引起的未来全球气候变化问题的决定性因子之一。红桦（Betula albosinensis Burk.）是川西亚高山采伐迹地自然或人工恢复的重要树种。本研究以1a红桦幼苗为模式植物，采用人工模拟的方法，研究CO2浓度升高对不同种内竞争强度（种群水平）下红桦幼苗的生理特征、生长、干物质积累及其分配的影响，探讨在种内竞争生长条件下红桦幼苗的“光合适应机理”与生长特征，为西南亚高山森林生产力对未来全球变化的预测提供重要参考。 本研究的主要结果如下： 1）在种内竞争生长条件下红桦幼苗经过CO2浓度升高熏蒸4个月后，叶片出现“光合适应”现象。与对照相比，低种植密度（28株m-2）和高种植密度（84株m-2）条件下的红桦幼苗净光合速率（A）、气孔导度（gs）、蒸腾速率（E）、表观量子产量（AQY）和羧化速率（CE）显著降低，而水分利用效率（WUE）则显著提高。CO2浓度升高处理的红桦幼苗叶片Rubisco活性、单位叶面积N浓度、叶绿素a、叶绿素b和类胡萝卜素浓度都显著降低。但CO2浓度对红桦幼苗的叶绿素a与叶绿素b的比值没有显著影响。CO2浓度升高显著增加红桦幼苗单位叶面积的非结构性碳水化合物（TNC）浓度，结果是红桦幼苗的比叶面积（SLA，cm2 g-1）显著降低。 2）与对照相比，CO2浓度升高处理的红桦幼苗高、基径、单叶面积和侧枝的相对生长速率（R GR）显著提高，尤其在试验处理的早期。CO2浓度升高既增加单株红桦幼苗总叶片数量又增加单叶面积，结果是单株红桦幼苗的总叶面积比对照显著增加。 3）CO2浓度升高处理显著增加红桦幼苗干物质积累（尤其是细根生物量），改变了红桦幼苗生物量的分配格局。与对照相比，CO2浓度升高处理的红桦幼苗叶重比（LWR）、叶面积比（LAR）、叶根重比（Wl/Wr）和源汇重比（leaf weight to non-leaf weight ratio, Wsource/Wsink）显著下降（高种植密度的LWR除外），而根冠比（R/S）则显著增加。在两种种植密度条件下，CO2浓度升高显著增加红桦幼苗根生物量的分配比率，显著降低叶片的生物量分配比率，对主茎、侧枝以及地上生物量的分配比率不变或约有下降。 总之，长期生长在CO2浓度升高条件下的红桦幼苗光合能力下降，并伴随Rubisco活性、叶N浓度、光合色素浓度的显著降低以及TNC浓度的显著增加。支持树木光合速率下降与Rubisco活性、叶N浓度下降以及TNC浓度增加紧密相关的假设。CO2浓度升高处理红桦幼苗的早期相对生长速率大大高于对照，而后期迅速下降，说明红桦幼苗生物量的显著增加主要归功于CO2浓度升高的早期促进作用和叶面积的显著增加。CO2浓度升高显著增加红桦幼苗根系生物量和根冠比，表明红桦幼苗“额外”固定的C向根系转移。 The steady increae of atmospheric CO2 concentration（[CO2]）has been inevitable fact. Models predict that the atmospheric [CO2] will increase to about 700µmol mol-1 at the end of the twenty-first century. As trees constitute a majoor carbon reservoir–85% of total plant carbon is found in forest, and their ability to sequester carbon is a key determinant of future global change problems caused by increases in atmospheric CO2. In addition to the role of forests in the global carbon cycle, inceased growth could be of economic benefit, for example, offsetting deleterious effects of climatic changes. Betula albosinensis (Burk.) usually emerges as the pioneer species in initial stage and as constructive species in later stages of forest community succession of mountain forest area, and also is one of important tree species for afforestation in logged area, in southwesten China. In this experinment, Betula albosinensis seedling (one-year-old) was used as the model plant. B. albosinensis seedlings were grown under two all-day [CO2], ambient (about 350 µmol·mol-1) and elevated [CO2] (about 700 µmol·mol-1), and two planting densities of 28 plants per m2 and 84 plants per m2. The objectives were to characterize birch mature leaf photosynthesis, growth, mass accumulation and allocation responses to long-tern elevated growth [CO2] under the influences of neighbouring plants, and to assess whether elevated [CO2] regulated birch mature leaf photosynthetic capacity, in terms of leaf nitrogen concentration (leaf [N]), activity of ribulose bisphosphate carboxygenase (Rubisco), Rubisco photosynthetic efficiency, and total nonstructural carbohydrates (TNC) concentration, and also to provide a strong reference to predict the productivity of subalpine forests under the future global changes. The results are as follows: 1) B.albosinensis seedlings exposed to elevated [CO2] for 120 days, photosynthetic acclimation phenomena occurred. At two planting densities, leaves of birch seedlings grown under elevated [CO2] had lower net photosynthetic rate (A), stomatal conductance (gs), transpiration (E), apparent quantum yield (AQY) and carboxylated efficiency (CE) and higher water use efficiency (WUE), compared to those of B.albosinensis seedlings grown under ambient [CO2]. Based on the leaf area, leaf [N], Rubisco activity and photosynthetic pigments concentrations of B. albosinensis seedlings grown under elevated [CO2] were significantly lower than those grown under ambient [CO2]. The ratio of chlorophyll a to chlorophyll b concentration was not affected by elevated [CO2]. Under elevated [CO2], the TNC concentration per unit leaf area significantly increased, resulting in significant decrease in specific leaf area. Thus leaf photosynthetic capacity of B. albosinensis seedlings would perform worse under rising atmospheric [CO2] and the influences of neighbouring plants. 2) Under elevated [CO2], the relative growth rate (RGR) of B. albosinensis seedlings height, basal diameter, a leaf area and branch length significantly increased, especially at the initial stage of exposure to elevated [CO2], and a leaf area and leaf numbers per B. albosinensis seedling also significantly increased. Thus the total leaf area per B. albosinensis seedling was significantly increased under elevated [CO2]. 3) As the increase of RGR and total leaf area, biomass of B. albosinensis seedling grown elevated [CO2] was higher, compared to that of B.albosinensis seedlings grown at ambient [CO2]. Elevated [CO2] changed the biomass allocation pattern of B. albosinensis seedling. At two planting densities, B. albosinensis seedlings grown elevated [CO2] had lower leaf weight to total weight ratio (LWR), leaf area to total weight ratio (LAR) and leaf weight to non-leaf weight ratio (Wsource/Wsink), but higher root weight to shoot weight ratio (R/S), compared to those of B.albosinensis seedlings grown at ambient [CO2]. Under elevated [CO2], roots biomass to total biomass ratio was signigicantly increased, leaves biomass to total biomass ratio was significantly decreased. The main stem and branch biomass to total biomass ratio were not affected by elevated [CO2]. In conclusion, our results supported the hypothesis that the decline in photosynthetic capacity of C3 plants will appear after long-term exposure to elevated [CO2], accompanying with the significant decrease in Rubisco activity, leaf N concentration, photosynthetic pigments concentration, and significant increase in total non-structural carbohydrates concentration. Our results also have shown that the increase of biomass of B. albosinensis seedlings should be attributed to initial stimulation on RGR and total leaf area resulted from elevated [CO2]. Under elevated [CO2], the extra carbon sequestered by B.albosinensis seedlings transferred into under-ground part because of increase in root biomass and R/S.

Role of cytokines in secondary lymphoid organ development

Summary Secondary lymphoid organs are sites of antigen presentation, clonal expansion of B and lymphocytes, and affinity maturation of B lymphocytes. In the intestine, these immune functions occur mainly in Peyer's patches (PP). PP develop through the interplay of two main cell types, haematopoietic cells and meserichyrnal cells. One particular haematopoietic cell type was identified as the inductive cell type in the formation of both PP and lymph nodes and was therefore designated as lymphoid tissue inducer cell. For a successful PP organogenesis, the crucial molecular components involved in the crosstalk of inducer cells and their mesenchymal target cells are adhesion molecules, lymphotoxin (LT) family members, and cytokines. In particular, the interleukin 7 receptor (IL-7R) expressed on inducer cells is absolutely required. To investigate the contribution of the ligand for the IL-7R. the cytokine IL-7, in the process of PP formation, we analyzed double transgenic (TG) mice. These mice resulted from an interbreeding of an IL-7TG mouse strain where the transgene is under the control of the MHC class II promoter with a second transgenic mouse strain, which overexpresses a transactivator for MHC class II genes. Double TG offsprings revealed higher levels of IL-7 mRNA occuring earlier in embryogenesis. Consequently, double TG mice showed a striking phenotype with a 3- to 5-fold increase in PP numbers compared to single IL-7TG or control littermates. Analysis of embryonic double TG intestines demonstrated that the process of PP development was already elevated during development as early as the embryonic day 16.5. Importantly, inducer cells were significantly increased in numbers in these embryonic intestines. Furthermore, the expression of LT? mRNA, which at this early time point is exclusively expressed by inducer cells, was also increased in double TG animals. These data clearly indicate a direct influence of IL-7 on the expansion of lymphoid tissue inducer cells and on the availability of LT? leading to a higher frequency of developing PP in fetal life. Interestingly, in addition to an enhanced frequency of PP development, in double TG mice, three additional phenotypic differences were observed. i) Lymphocyte infiltration in various non-lymphoid organs, such as stomach, salivary gland, and liver. Subsequent analysis demonstrated that B lymphocytes were predominant within these tertiary lymphoid structures. ii) Ectopic lymph node-like structures containing both B and T lymphocytes were found near the inguinal lymph node. iii) Double TG mice had a severe bone resorption syndrome most likely as a consequence of the pro-osteoclastic effect of IL-7. Taken together, these results show that IL-7 plays a key role in the homeostasis of inducer cells, in the generation of PP in the gut, in the formation of ectopic lymphoid tissue, and in bone resorption. Résumé Les organes lymphoïdes secondaires sont les lieux de présentation des antigènes aux lymphocytes, permettant l'expansion des lymphocytes B et T et la maturation d'affinité des lymphocytes B. Dans l'intestin, ces fonctions immunitaires se déroulent dans les plaques de Peyer (PP). Ces plaques se développent grâce à l'interaction des cellules hématopoïétiques avec des cellules mésenchymales. Un type particulier de cellules hématopoïétiques a été identifié comme cellule inductrice dans la formation des PP et des ganglions lymphatiques et de ce fait a été désigné cellule inductrice des tissus lymphoïdes. Durant l'organogénèse des PP, les composants moléculaires cruciaux impliqués dans l'interaction des cellules inductrices et des cellules mésenchymales sont les molécules d'adhésion, les membres de la famille des lymphotoxines (LT) et les cytokines. En particulier, le récepteur de l'interleukine 7 (IL-7R) exprimé par les cellules inductrices est absolument nécessaire. Pour étudier le rôle du ligand de l'IL-7R, l'interleukine IL-7, dans la formation des PP, nous avons croisé une lignée de souris transgénique (TG) surexprimant IL-7 sous contrôle du promoteur MHC class Il avec une lignée de souris transgénique surexprimant un transactivateur des genes MHC class II. Les souris doubles TG présentent une concentration élevée d'ARNm de l'IL-7 durant l'embryogénèse, ce qui résulte en une augmentation du nombre de PP de 3 à 5 fois en comparaison aux souris ayant seul le transgène IL-7 et aux souris contrôles. L'analyse des intestins des souris doubles TG démontre que le processus de développement des PP était élevé dès le jour 16.5 du développement embryonnaire. L'augmentation du nombre des cellules inductrices dans ces intestins embryonnaires est signilicative. De plus l'expression de l'ARNm LT?, qui à ce stade précoce est exclusivement exprimé dans les cellules inductrices, est également augmenté dans les doubles TG. Ces résultats indiquent clairement une influence directe d'IL-7 sur l'expansion des cellules inductrices des tissues lymphoïdes et sur la synthèse de LT? induisant une augmentation des PP se développant durant la vie foetale. En plus du développement accru des PP dans les souris doubles TG, trois différences phénotypiques ont été observées. i) L'infiltration lymphocytaire dans différents organes non-lymphoïdes, comme l'estomac, les glandes salivaires et le foie. Des analyses complémentaires ont demontré que les lymphocytes B étaient prédominants dans ces structures lymphoïdes tertiaires. ii) Des structures de ganglions lymphatiques ectopiques contenant des lymphocytes B et T ont été trouvées près des ganglions lymphatiques inguinaux. iii) Les souris doubles TG présentent un syndrome de résorption osseuse sévère probablement dû à l'effet pro-osteoclaste d'IL-7. Globalement, ces résultats montrent que IL-7 joue un rôle clé dans l'homéostasie des cellules inductrices dans la génèse de PP de l'intestin, dans la formation des tissus lymphoïdes ectopiques et dans la résorption osseuse.

Memory versus naive T-cell migration

Our established understanding of lymphocyte migration suggests that naive and memory T cells travel throughout the body via divergent pathways; naive T cells circulate between blood and lymph whereas memory T cells additionally migrate through non-lymphoid organs. Evidence is now gradually emerging which suggests such disparate pathways between naive and memory T cells may not strictly be true, and that naive T cells gain access to the non-lymphoid environment in numbers approaching that of memory T cells. We discuss here the evidence for naive T-cell traffic into the non-lymphoid environment, compare and contrast this movement with what is known of memory T cells, and finally discuss the functional importance of why naive T cells might access the parenchymal tissues.

Promising pre-clinical validation of targeted radionuclide therapy using a [131I] labelled iodoquinoxaline derivative for an effective melanoma treatment

Targeted internal radionuclide therapy (TRT) would be an effective alternative to current therapies for dissemi- nated melanoma treatment. At our institution, a class of iodobenzamides has been developed as potent melanoma- seeking agents. This review described the preclinical vali- dations of a quinoxaline derivative molecule (ICF01012) as tracer for TRT application. It was selected for its high, specific and long-lasting uptake in tumour with rapid clear- ance from non-target organs providing suitable dosimetry parameters for TRT. Extended in vivo study of metabolic profiles confirmed durable tumoural concentration of the unchanged molecule form. Moreover melanin specificity of ICF01012 was determined by binding assay with syn- thetic melanin and in vivo by SIMS imaging. Then, we showed in vivo that [131I] ICF01012 treatment drastically inhibited growth of B16F0, B16Bl6 and M4Beu tumours whereas [131I] NaI or unlabelled ICF01012 treatment was without significant effect. Histological analysis showed that residual tumour cells exhibit a significant loss of aggres- siveness after treatment. This anti-tumoural effect was associated with a lengthening of the treated-mice survival time and an inhibition of lung dissemination for B16Bl6 model. Results presented here support the concept of TRT using a [131I] labelled iodoquinoxaline derivative for an effective melanoma treatment.

PET imaging of tumours with a 64Cu labeled macrobicyclic cage amine ligand tethered to Tyr3-octreotate

The use of copper radioisotopes in cancer diagnosis and radionuclide therapy is possible using chelators that are capable of binding Cu(II) with sufficient stability in vivo to provide high tumour-to-background contrast. Here we report the design and synthesis of a new bifunctional chelator, 5-(8-methyl-3,6,10,13,16,19-hexaaza-bicyclo[6.6.6]icosan-1-ylamino)-5-oxopentanoic acid (MeCOSar), that forms copper complexes of exceptional stability by virtue of a cage amine (sarcophagine) ligand and a new conjugate referred to as SarTATE, obtained by the conjugation of MeCOSar to the tumour-targeting peptide Tyr(3)-octreotate. Radiolabeling of SarTATE with (64)Cu(II), a radioisotope suitable for positron emission tomography (PET), was fast (~20 min), easily performed at room temperature and consistently resulted in high radiochemical purity (>99%). In vitro and in vivo evaluation of (64)CuSarTATE demonstrated its high selectivity for tumour cells expressing somatostatin receptor 2 (sstr2). Biodistribution and PET imaging comparisons were made between (64)CuSarTATE and (64)Cu-labeled DOTA-Tyr(3)-octreotate ((64)CuDOTATATE). Both radiopharmaceuticals showed excellent uptake in sstr2-positive tumours at 2 h post-injection. While tumour uptake of (64)CuDOTATATE decreased significantly at 24 h, (64)CuSarTATE activity was retained, improving contrast at later time points. (64)CuSarTATE accumulated less than (64)CuDOTATATE in the non-target organs, liver and lungs. The uptake of (64)CuSarTATE in the kidneys was high at 2 h but showed significant clearance by 24 h. The new chemistry and pre-clinical evaluation presented here demonstrates that MeCOSar is a promising bifunctional chelator for Tyr(3)-octreotate that could be applied to a combined imaging and therapeutic regimen using a combination of (64)Cu- and (67)CuSarTATE complexes, owing to improved tumour-to-non-target organ ratios compared to (64)CuDOTATATE at longer time points.

A negação da autonomia universitária na política educacional do governo federal (2003-2008) e do governo do estado de São Paulo (2007)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)