BACKGROUND & AIMS: :Rat brain synaptosomal membranes that are depleted of endogenous excitatory amino acids cannot bind [(+)-5-methyl-10, 11-dihydro-5H-dibenzo(a,d]cyclohept-5,10-imine maleate] ([3H]MK-801). However, they do so upon the restoration of excitatory amino acid agonists such as L-glutamate. [3H]MK-801 provides a molecular probe which is specific for a binding site located within the ionophore of the N-methyl-D-aspartate-type excitatory amino acid receptor, [3H]MK-801 does not bind to non-N-methyl-D-aspartate excitatory amino acid receptors. Exploiting [3H]MK-801 binding as a quantitative measure of agonist activity with respect to ability of inducing the open channel conformation, the present study demonstrates that L-homocysteate is an agonist almost equivalent to L-glutamate in terms of efficacy (maximal N-methyl-D-aspartate response) as well as potency (EC50). The effect of L-homocysteate was dose-dependent, stereospecific (L-homocysteate greater than DL-homocysteate greater than D-homocysteate), suppressible by the N-methyl-D-aspartate-selective competitive antagonist (+/-)-3(2-carboxy-piperazine-4-yl)propyl-l-phosphonate, and potentiated by the N-methyl-D-aspartate-selective "allosteric" modulator glycine. The demonstrated inactivity of L-homocysteine (and virtually all naturally occurring, non-acidic amino acids) implies that the omega-sulphonic acid moiety is an acceptable substitute for the omega carboxyl group for activating the N-methyl-D-aspartate receptor. While the potency of L-homocysteate at N-methyl-D-aspartate receptors was by a factor of only 1.6 smaller than that of L-glutamate, the affinity of L-homocysteate for kainate-type excitatory amino acid receptors was approximately four-fold lower than that of L-glutamate.(ABSTRACT TRUNCATED AT 250 WORDS)

背景与目标： : 消耗内源性兴奋性氨基酸的大鼠脑突触体膜不能结合 [(+)-5-甲基-10,11-dihydro-5H-dibenzo(a，d]cyclohept-5，马来酸10-亚胺] ([3H]MK-801)。它们是在兴奋性氨基酸激动剂如L-谷氨酸恢复时这样做的。[3H]MK-801提供了一种分子探针，该探针对位于N-甲基-D-天冬氨酸型兴奋性氨基酸受体的离子载体内的结合位点具有特异性，[3H]MK-801不结合非N-甲基-D-天冬氨酸兴奋性氨基酸受体。利用 [3H]MK-801结合作为关于诱导开放通道构象能力的激动剂活性的定量测量，本研究表明，L-同型半胱氨酸在功效 (最大N-甲基-D-天冬氨酸反应) 和效力 (EC50) 方面几乎等同于L-谷氨酸。L-同型半胱氨酸的作用是剂量依赖性的，立体特异性 (L-高半胱氨酸大于DL-高半胱氨酸大于D-高半胱氨酸)，可被N-甲基-D-天冬氨酸选择性竞争性拮抗剂 (/-)-3(2-羧基哌嗪-4-基) 丙基-l-膦酸酯抑制，并由N-甲基-D-天冬氨酸选择性 “变构” 调节剂甘氨酸增强。已证明L-高半胱氨酸 (几乎所有天然存在的，非酸性氨基酸) 意味着 ω-磺酸部分是激活N-甲基-D-天冬氨酸受体的 ω 羧基的可接受替代品。而L-同型半胱氨酸在N-甲基-D-天冬氨酸受体上的效力仅比1.6小L-谷氨酸，L-同型半胱氨酸对红藻氨酸型兴奋性氨基酸受体的亲和力大约比L-谷氨酸低4倍。(摘要截短于250字)

BACKGROUND & AIMS: :The osmotolerant yeast Zygosaccharomyces rouxii is sensitive to the toxic L-proline analogue, L-azetidine-2-carboxylate (AZC). The possibility of use of the Saccharomyces cerevisiae MPR1 gene (ScMPR1) encoding the AZC-detoxifying enzyme as a dominant selection marker in Z. rouxii was examined. The heterologous expression of ScMPR1 in two Z. rouxii strains resulted in AZC-resistant colonies, but that of ScMPR1 as a dominant marker gene in vectors was affected by a high frequency of spontaneously resistant colonies. The same was found for an AZC-sensitive S. cerevisiae strain in which the ScMPR1 was expressed. In both yeasts, ScMPR1 can be used only as an auxiliary marker gene.

背景与目标： : 耐渗透酵母酵母rouxii对有毒的L-脯氨酸类似物L-azetidine-2-carboxylate (AZC) 敏感。研究了使用编码AZC解毒酶的酿酒酵母MPR1基因 (ScMPR1) 作为Z. rouxii中主要选择标记的可能性。ScMPR1在两个Z. rouxii菌株中的异源表达导致AZC抗性菌落，但是ScMPR1作为载体中的显性标记基因受到自发抗性菌落的高频率影响。对于表达ScMPR1的AZC敏感的酿酒酵母菌株，发现了相同的结果。在两种酵母中，ScMPR1只能用作辅助标记基因。

BACKGROUND & AIMS: Using a melt-pressing technique, we produced a small solid cylinder containing cisplatin (CDDP) embedded in poly-d, l-lactic acid (CDDP-PLA). The in vitro release of CDDP from the polymer was examined in an immersion system. CDDP was released continuously for more than four weeks with no initial burst. Drug distribution for CDDP-PLA was compared with CDDP solution (CDDP-SOL) by subcutaneous administration into the back of rats. In the CDDP-PLA group, a high concentration of CDDP was maintained in the subcutaneous tissues near the implants for 20 days. However, in the CDDP-SOL group, the concentration of CDDP was low by 10 days after drug administration. CDDP-PLA may become a useful tool in locoregional chemotherapy as a solid type of drug delivery system with longlasting release.

背景与目标： 使用熔融压制技术，我们生产了一个小的固体圆柱体，其中包含嵌入聚d，l-乳酸 (CDDP-PLA) 中的顺铂 (CDDP)。在浸没系统中检查了CDDP从聚合物中的体外释放。CDDP连续发布超过四个星期，没有初始爆发。通过皮下给药到大鼠背部，将CDDP-PLA的药物分布与CDDP溶液 (CDDP-SOL) 进行比较。在cddp-pla组中，在植入物附近的皮下组织中维持高浓度的CDDP 20天。然而，在CDDP-SOL组中，给药后10天CDDP的浓度较低。Cddp-pla作为一种具有持久释放的固体药物输送系统，可能成为局部化疗的有用工具。

BACKGROUND & AIMS: :The effect of immobilization on cell physiology and how this determines cell metabolic performance is an important concern for developing bioprocess. This is particularly true for genetically modified microorganisms and their genetic stability. For this reason the stability and physiological state of plasmid-bearing E. coli cells were ascertained by flow cytometry. Differences in the cellular DNA and protein content (15-20%) permit discrimination of control and plasmid-bearing cells, as well as adaptation to continuous cultivation conditions in both freely suspended and immobilized states to be monitored. Moreover, the observed metabolic burden due to maintenance and over-expression of plasmid-coded genetic material and slow cell growth in poorly-viable immobilized cells were found to be the main factors contributing to strain stabilization.

背景与目标： : 固定化对细胞生理的影响以及这如何决定细胞代谢性能是发展生物过程的重要问题。对于转基因微生物及其遗传稳定性尤其如此。因此，通过流式细胞术确定了带有质粒的大肠杆菌细胞的稳定性和生理状态。细胞DNA和蛋白质含量 (15-20%) 的差异允许区分对照和携带质粒的细胞，以及适应在自由悬浮和固定状态下的连续培养条件，以进行监测。此外，发现由于质粒编码的遗传物质的维持和过度表达以及活动性较差的固定化细胞中的细胞生长缓慢而导致的代谢负担是导致菌株稳定的主要因素。

BACKGROUND & AIMS: Winterhardiness in cereals is the consequence of a number of complex and interacting componentscold tolerance, vernalization requirement and photoperiod sensitivity. An understanding of the genetic basis of these component traits should allow for more effective selection. Genome map-based analyses hold considerable promise for dissecting complex phenotypes. A 74-point linkage map was developed from one hundred double haploid lines derived from a winter x spring barley cross and used as the basis for quantitative trait locus (QTL) analyses to determine the chromosome location of genes controlling components of winterhardiness. Despite the greater genome coverage provided by the current map, a previously-reported interval on chromosome 7 remains the only region where significant QTL effects for winter survival were detected in this population. QTLs for heading date under 24 h light map to the same region. A QTL for heading date under this photoperiod regime also maps to chromosome 2. A distinct set of QTLs mapping to chromosomes 1, 2, 3 and 5 determined heading date under 8 h light. Patterns of differential QTL expression underscore the complexity of Winterhardiness.

背景与目标： 谷物的耐寒性是许多复杂且相互作用的成分的耐受性，春化要求和光周期敏感性的结果。对这些组成性状的遗传基础的理解应该可以进行更有效的选择。基于基因组图谱的分析为解剖复杂的表型提供了可观的前景。从来自冬季x春季大麦杂交的100个双单倍体系开发了一个74点连锁图谱，并将其用作定量性状基因座 (QTL) 分析的基础，以确定控制耐寒性成分的基因的染色体位置。尽管当前地图提供了更大的基因组覆盖率，但先前报道的7号染色体间隔仍然是在该人群中检测到冬季生存的显着QTL影响的唯一区域。24 h光照图下到同一区域的航向日期的qtl。在这种光周期下，用于抽头日期的QTL也映射到2号染色体。映射到1、2、3和5号染色体的一组不同的qtl确定了在8小时光照下的标题日期。差异QTL表达的模式强调了耐寒性的复杂性。

BACKGROUND & AIMS: :Angiotensin II is involved in tumor growth; however, the precise mechanism is not known. Platelets also contribute to tumor growth, and angiotensin II type 1 receptor (AT1) is expressed on the platelet surface. We hypothesized that interaction of platelets with tumor cells through AT1 receptor signaling promotes tumor metastasis. B16F1 melanoma cells were intravenously injected into Agtr1a knockout mice (AT1a(-/-)) and wild-type littermates (WT); the AT1a(-/-) mice exhibited a reduction in lung colonies. Angiotensin II induced expression of P-selectin on platelets in WT but not in AT1a(-/-) mice. A selective P-selectin neutralizing antibody decreased lung colony numbers in WT but not in AT1a(-/-) mice. Levels of vascular endothelial growth factor (VEGF) and stromal cell-derived factor 1 (SDF-1) receptor in platelets at metastatic locus were lower in AT1a(-/-) mice. Treatment of neutralizing antibodies against VEGF and CXCR4 decreased lung colony numbers in WT but not in AT1a(-/-) mice. In AT1a(-/-) mice, and both mobilization of progenitor cells expressing CXCR4(+)VEGFR1(+) cells from bone marrow and their recruitment to lung tissues were suppressed. These results suggest that AT1A signaling plays a critical role in tumor metastasis through P-selectin-mediated interactions of platelets with tumor and endothelial cells and through the AT1A signaling-dependent production of VEGF and SDF-1, which may be involved in mobilization of CXCR4(+)VEGFR1(+) cells.

背景与目标： : 血管紧张素II参与肿瘤生长; 然而，确切的机制尚不清楚。血小板也有助于肿瘤生长，血管紧张素II 1型受体 (AT1) 在血小板表面表达。我们假设血小板通过AT1受体信号与肿瘤细胞的相互作用促进肿瘤转移。将B16F1黑色素瘤细胞静脉注射到Agtr1a基因敲除小鼠 (AT1a(-/-)) 和野生型同窝动物 (WT) 中; AT1a(-/-) 小鼠的肺集落减少。血管紧张素II在WT中诱导P-选择素在血小板上的表达，但在AT1a(-/-) 小鼠中不诱导P-选择素的表达。选择性P-选择素中和抗体降低了WT中的肺集落数量，但在AT1a(-/-) 小鼠中却没有。在AT1a(-/-) 小鼠中，转移基因座的血小板中血管内皮生长因子 (VEGF) 和基质细胞衍生因子1 (SDF-1) 受体的水平较低。针对VEGF和CXCR4的中和抗体的处理减少了WT中的肺集落数量，但在AT1a(-/-) 小鼠中却没有。在AT1a(-/-) 小鼠中，表达CXCR4 () VEGFR1 () 细胞的祖细胞从骨髓中的动员及其向肺组织的募集均受到抑制。这些结果表明，AT1A信号通过P-选择素介导的血小板与肿瘤和内皮细胞的相互作用以及通过AT1A信号依赖性产生VEGF和SDF-1在肿瘤转移中起关键作用，这可能与CXCR4 () VEGFR1 () 细胞的动员有关。

BACKGROUND & AIMS: :In anther cultures of Solanum carolinense L., Murashige and Skoog's medium (MS) supplemented with 2.2 mg · l(-1) 2,4-dichlorophenoxyacetic acid (2,4-D) and 6.0 mg · l(-1) kinetin (KIN) served as callus induction medium. Cytological observations confirmed that the callus originated from pollen grains. Upon transfer to medium lacking 2,4-D, callus cultures regenerated shoots exclusively. However, maximum efficiency in regeneration occurred only after callus had been maintained in the presence of 2,4-D for a minimum of 12 weeks. Callus younger than this or older than 16 weeks showed a significant decline in organogenic competence when transferred to the appropriate medium. It is suggested that 2,4-D may establish a transitory potential for regeneration in pollen-derived callus cultures but must be removed before this potential can be expressed.

背景与目标： : 在茄属植物的花药培养物中，补充了2.2 mg·L (-1) 2,4-二氯苯氧基乙酸 (2,4-d) 和6.0 mg · l(-1) 激动素 (KIN) 的Murashige和Skoog's培养基 (MS) 用作愈伤组织诱导培养基。细胞学观察证实愈伤组织起源于花粉粒。转移到缺乏2,4-d的培养基后，愈伤组织培养物仅再生芽。然而，只有在2,4-d存在下将愈伤组织维持至少12周后，才能产生最大的再生效率。小于此年龄或大于16周的愈伤组织转移到适当的培养基后，其器官发生能力显着下降。建议2,4-d可能会在花粉衍生的愈伤组织培养物中建立短暂的再生潜力，但必须先将其去除，然后才能表达这种潜力。

BACKGROUND & AIMS: :Oxidation of low density lipoproteins (LDL) favours cholesterol loading in macrophages and formation of "foam cells", typical of the early atheroma lesions. LDL cholesterol oxidation generates oxysterols, extremely cytotoxic molecular species with diverse biological activities. Vegetable polyphenols are dietary components of pharmacological interest for their anti-oxidant properties. Ginkgo biloba L. (Gingkoaceae) leaves and Vaccinium myrtillus L. (Ericaceae) fruits are known for their beneficial effects in the treatment of various diseases involving free radicals and oxidative damage to biological lipids. In this study we investigated the effect of Ginkgo biloba L. and Vaccinium myrtillus L. extracts on the formation of cholesterol oxides during the photo induced oxidation of human LDL. The results demonstrate a concentration dependent inhibition of oxysterol formation in the presence of both extracts. Protection against oxidation was confirmed by the partial restoration of the normal electrophoretic mobility of LDL, which has been influenced by the UV irradiation. These effects extend knowledge of the therapeutic action of Ginkgo biloba L. and Vaccinium myrtillus L. as agents in anti-atherosclerotic regimens.

背景与目标： : 低密度脂蛋白 (LDL) 的氧化有利于巨噬细胞中的胆固醇负荷和 “泡沫细胞” 的形成，这是早期动脉粥样硬化病变的典型特征。LDL胆固醇氧化生成氧固醇，具有多种生物活性，具有极强的细胞毒性分子。植物多酚因其抗氧化特性而具有药理学意义的饮食成分。银杏L.(银杏科) 叶子和越橘桃金娘。(Ericaceae) 水果以其在治疗涉及自由基和对生物脂质的氧化损伤的各种疾病中的有益作用而闻名。在这项研究中，我们研究了银杏叶和桃花越橘提取物在光诱导的人LDL氧化过程中对胆固醇氧化物形成的影响。结果表明，在两种提取物的存在下，氧固醇形成的浓度依赖性抑制作用。LDL正常电泳迁移率的部分恢复证实了抗氧化作用，这已受到紫外线照射的影响。这些作用扩展了银杏叶和桃花越橘作为抗动脉粥样硬化治疗药物的治疗作用的知识。

BACKGROUND & AIMS: :Relationships among traits were investigated on the genomic and residual levels using novel methodology. This included inference on these relationships via Bayesian networks and an assessment of the networks with structural equation models. The methodology employed three steps. First, a Bayesian multiple-trait Gaussian model was fitted to the data to decompose phenotypic values into their genomic and residual components. Second, genomic and residual network structures among traits were learned from estimates of these two components. Network learning was performed using six different algorithmic settings for comparison, of which two were score-based and four were constraint-based approaches. Third, structural equation model analyses ranked the networks in terms of goodness of fit and predictive ability, and compared them with the standard multiple-trait fully recursive network. The methodology was applied to experimental data representing the European heterotic maize pools Dent and Flint (Zea mays L.). Inferences on genomic and residual trait connections were depicted separately as directed acyclic graphs. These graphs provide information beyond mere pairwise genetic or residual associations between traits, illustrating for example conditional independencies and hinting at potential causal links among traits. Network analysis suggested some genetic correlations as potentially spurious. Genomic and residual networks were compared between Dent and Flint.

背景与目标： : 使用新颖的方法在基因组和残留水平上研究了性状之间的关系。这包括通过贝叶斯网络对这些关系的推断以及使用结构方程模型对网络的评估。该方法采用了三个步骤。首先，将贝叶斯多性状高斯模型拟合到数据，以将表型值分解为其基因组和残差成分。其次，从这两个组成部分的估计中学习了性状之间的基因组和残余网络结构。网络学习是使用六种不同的算法设置进行比较的，其中两种是基于分数的，四种是基于约束的方法。第三，结构方程模型分析根据拟合优度和预测能力对网络进行了排名，并将它们与标准的多性状全递归网络进行了比较。该方法应用于代表欧洲杂种玉米库Dent和Flint (Zea mays L.) 的实验数据。关于基因组和残余性状连接的推论被分别描述为有向无环图。这些图提供的信息不仅仅是性状之间的成对遗传或残留关联，例如说明条件独立性并暗示性状之间的潜在因果关系。网络分析表明，某些遗传相关性可能是虚假的。比较了凹痕和火石之间的基因组和残余网络。

BACKGROUND & AIMS: :Fructans are the main storage compound in Lolium perenne. To account for the prevailing neokestose-based fructan synthesis in this species, a cDNA library of L. perenne was screened by using the onion (Allium cepa) fructan:fructan 6G-fructosyltransferase (6G-FFT) as a probe. A full length Lp6G-FFT clone was isolated with significant homologies to vacuolar type fructosyltransferases and invertases. The functionality of the cDNA was tested by heterologous expression in Pichia pastoris. The recombinant protein demonstrated both 6G-FFT and fructan:fructan 1-fructosyltransferase activities (1-FFT) with a maximum 6G-FFT/1-FFT ratio of two. The activity of 6G-FFT was investigated with respect to developmental stage, tissue distribution, and alterations in carbohydrate status expression and compared to sucrose:sucrose 1-fructosyltransferase (1-SST). Lp6G-FFT and Lp1-SST were predominantly expressed in the basal part of elongating leaves and leaf sheaths. Expression of both genes declined along the leaf axis, in parallel with the spatial occurrence of fructan and fructosyltransferase activities. Surprisingly, Lp6G-FFT was highly expressed in photosynthetically active tissues where very low extractable fructosyltransferase activity and fructan amounts were detected, suggesting a post-transcriptional regulation of expression. Lp6G-FFT gene expression increased only in elongating leaves following similar increases of sucrose content in blades, sheaths, and elongating leaf bases. Regulation of Lp6G-FFT gene expression depends on the tissue according to its sink-source status.

背景与目标： : 果聚糖是黑麦草中的主要储存化合物。为了说明该物种中主要的基于新糖的果聚糖合成，通过使用洋葱 (葱属) 果聚糖: 果聚糖6g-果糖基转移酶 (6G-FFT) 作为探针，筛选了perenne的cDNA文库。分离出与液泡型果糖基转移酶和转化酶具有显着同源性的全长Lp6G-FFT克隆。通过在毕赤酵母中的异源表达来测试cDNA的功能。重组蛋白同时显示6G-FFT和果聚糖: 果聚糖1-果糖基转移酶活性 (1-FFT)，最大6G-FFT/1-FFT比为2。研究了6G-FFT的活性，涉及发育阶段，组织分布和碳水化合物状态表达的变化，并与蔗糖: 蔗糖1-果糖基转移酶 (1-SST) 进行了比较。Lp6G-FFT和Lp1-SST主要在伸长的叶片和叶鞘的基部表达。这两个基因的表达沿叶轴下降，与果聚糖和果糖基转移酶活性的空间发生平行。令人惊讶的是，Lp6G-FFT在光合活性组织中高度表达，其中检测到非常低的可提取果糖基转移酶活性和果聚糖量，表明表达的转录后调节。在叶片，鞘和伸长叶基中蔗糖含量的类似增加之后，Lp6G-FFT基因的表达仅在伸长的叶片中增加。Lp6G-FFT基因表达的调节取决于组织的信源状态。

BACKGROUND & AIMS: :The expression of the engrailed homeobox gene during trout embryogenesis has been examined using immunohistochemistry and the monoclonal antibody 'Mab 4D9'. Engrailed has been suggested to play an important role during development by controlling position-specific characteristics in the CNS of the early embryo. In the present study we have analyzed the expression of engrailed at 5 stages of embryonic development of the trout (Salmo fario L.). The earliest stage analyzed was when the optic vesicles appear. Engrailed was then expressed in the posterior mesencephalon and anterior metencephalon, in a caudorostrally decreasing gradient. As the embryo develops, the pattern of the engrailed expression increases in spatial complexity. Thus, in the later stages of development, just before hatching, engrailed was found in hypothalamic areas, the germinative matrix layer of the cerebellum, the mesencephalic tegmentum, the caudal optic tectum and in the area of the trigeminal motor nucleus. This is similar to the distribution of engrailed in embryos of amphibians, birds and mammals.

背景与目标： : 已使用免疫组织化学和单克隆抗体 “mab 4D9” 检查了鳟鱼胚胎发生过程中缺失的同源盒基因的表达。已建议通过控制早期胚胎CNS的特定位置特征，在发育过程中发挥重要作用。在本研究中，我们分析了鳟鱼胚胎发育的5个阶段 (Salmo fario L.) 的表达。分析的最早阶段是视小泡出现的时间。然后在后脑中脑和前脑中以尾向降低的梯度表达。随着胚胎的发育，胚胎表达的模式会增加空间复杂性。因此，在发育的后期，即孵化之前，在下丘脑区域，小脑的发芽基质层，中脑被盖，尾视神经盖和三叉神经运动核区域发现了engrabed。这类似于两栖动物，鸟类和哺乳动物的胚胎中engraled的分布。

BACKGROUND & AIMS: :The purpose of this study was to assess the possible role of muscles in offsetting the anterior shear forces caused by the load and upper body mass and their accelerations that act on the L 4L 5, intervertebral joint during dynamic squat lifts. Fifteen males lifted five loads from 5.8 to 32.4 kg. Anterior shear forces estimated to be acting on the lumber spine, based on model output, ranged from 492 N at 5.8 kg to 736 N at 32.4 kg. However, the peak shear force that had to be supported by the facets and possibly the disc remained relatively constant at approximately 200 N, regardless of the load mass. The posteriorly directed fascicles of the lumbar portions of the iliocostalis lumborum and longissimus thoracis muscles increased their force output, as estimated from an EMG driven model, in proportion to the anterior load shear force demands, thereby sharing the load on the intervertebral joint. It appears that the combination of anatomical design and neural control of the musculature leads to a situation where the resultant shear force on the joint can be maintained at a relatively constant and safe level in the types of lifts studied. This 'safety' mechanism is useful only with the preservation of lordosis during lifting, when the muscles must provide the majority of the support moment.

背景与目标： : 这项研究的目的是评估肌肉在抵消动态下蹲提升过程中作用于L 4L 5椎间关节的负荷和上半身质量及其加速度引起的前剪切力中的可能作用。十五只雄性从5.8举起五只重物到32.4千克。根据模型输出，估计作用在木材脊柱上的前剪切力范围为5.8千克时的492 N至32.4千克时的736 N。然而，无论负载质量如何，必须由小平面和可能的圆盘支撑的峰值剪切力保持在大约200 N处相对恒定。根据EMG驱动模型估算，The肋腰和胸肌的腰部部分的后向束与前载荷剪切力需求成比例地增加了其力输出，从而分担了椎间关节的载荷。看来，解剖设计和肌肉组织的神经控制的结合导致了这样一种情况，即在所研究的提升类型中，关节上的合力剪切力可以保持在相对恒定且安全的水平。这种 “安全” 机制仅在举起期间保留脊柱前凸时有用，此时肌肉必须提供大部分支撑时刻。

BACKGROUND & AIMS: :Spinacia oleracea L. (spinach) is a dioecious species with both male and female plants having 2n = 2x = 12 chromosomes, consisting of two large metacentrics, two long subtelocentrics, two short subtelocentrics, two acrocentrics, and four submetacentrics. The location of 45S rDNA was investigated on metaphase chromosomes using fluorescence in situ hybridization (FISH). The numbers of 45S rDNA foci in diploid sets of chromosomes from females was six and from males was five. All the fluorescent foci lay in secondary constrictions and the satellites. Our results indicate that an XY-type sex chromosome system could be present in spinach where the Y chromosome lacks a 45S RNA focus.

背景与目标： : 尖刺(菠菜) 是雌雄异株的物种，雄性和雌性植物均具有2n = 2x = 12条染色体，由两个大的亚超中心，两个长的亚超中心，两个短的亚超中心，两个中心和四个亚超中心组成。使用荧光原位杂交 (FISH) 研究了45S rDNA在中期染色体上的位置。女性二倍体染色体组中45S rDNA病灶的数量为6，男性为5。所有的荧光灶都位于次级收缩和卫星中。我们的结果表明，菠菜中可能存在XY型性染色体系统，其中Y染色体缺乏45S RNA焦点。

BACKGROUND & AIMS: :Cell-based treatments for insulin-dependent diabetes (IDD) may provide more physiologic regulation of blood glucose levels than daily insulin injections, thereby reducing the occurrence of secondary complications associated with diabetes. An autologous cell source is especially attractive for regulatory and ethical reasons in addition to eliminating the need for immunosuppression. This study uses non-beta-cells, genetically modified for physiologic insulin secretion. Enteroendocrine L-cells, exhibit regulated secretion in response to physiologic stimuli and their endogenous products are fully compatible with prandial metabolism. Murine GLUTag L-cells were transfected with a plasmid co-expressing human insulin and neomycin resistance and the stable cell line, GLUTag-INS, was established. Secretion properties of GLUTag-INS cells were investigated in vitro through induced secretion tests using meat hydrolysate or 3-isobutyl-1-methylxanthine and forskolin as secretagogues. GLUTag-INS cells rapidly co-secreted recombinant insulin and endogenous glucagon-like peptide in response to metabolic cues from the surrounding medium and demonstrated efficient processing of proinsulin to insulin.

背景与目标： : 基于细胞的胰岛素依赖型糖尿病 (IDD) 治疗可能比每天注射胰岛素提供更多的血糖生理调节，从而减少与糖尿病相关的继发性并发症的发生。除了消除免疫抑制的需要外，自体细胞来源出于监管和伦理原因特别有吸引力。这项研究使用基因修饰的非 β 细胞进行生理性胰岛素分泌。肠内分泌L细胞在生理刺激下表现出调节的分泌，其内源性产物与饮食代谢完全兼容。用共表达人胰岛素和新霉素抗性的质粒转染鼠GLUTag L细胞，并建立了稳定的细胞系GLUTag-INS。使用肉水解物或3-异丁基-1-甲基黄嘌呤和forskolin作为促分泌剂，通过诱导分泌试验，在体外研究了GLUTag-INS细胞的分泌特性。GLUTag-INS细胞响应周围培养基的代谢线索迅速共同分泌重组胰岛素和内源性胰高血糖素样肽，并证明了胰岛素原向胰岛素的有效加工。

BACKGROUND & AIMS: BACKGROUND:Heterosis in internode elongation and plant height are commonly observed in hybrid plants, and higher GAs contents were found to be correlated with the heterosis in plant height. However, the molecular basis for the increased internode elongation in hybrids is unknown. RESULTS:In this study, heterosis in plant height was determined in two wheat hybrids, and it was found that the increased elongation of the uppermost internode contributed mostly to the heterosis in plant height. Higher GA4 level was also observed in a wheat hybrid. By using the uppermost internode tissues of wheat, we examined expression patterns of genes participating in both GA biosynthesis and GA response pathways between a hybrid and its parental inbreds. Our results indicated that among the 18 genes analyzed, genes encoding enzymes that promote synthesis of bioactive GAs, and genes that act as positive components in the GA response pathways were up-regulated in hybrid, whereas genes encoding enzymes that deactivate bioactive GAs, and genes that act as negative components of GA response pathways were down-regulated in hybrid. Moreover, the putative wheat GA receptor gene TaGID1, and two GA responsive genes participating in internode elongation, GIP and XET, were also up-regulated in hybrid. A model for GA and heterosis in wheat plant height was proposed. CONCLUSION:Our results provided molecular evidences not only for the higher GA levels and more active GA biosynthesis in hybrid, but also for the heterosis in plant height of wheat and possibly other cereal crops.

背景与目标：