脑桥呼吸调整中枢向中缝大核下行投射的研究

实验在23只苯巴比妥钠麻醉(i.p.30mg/kg)的成年猫上进行。在脑桥呼吸调整中枢(NPBM-KF)共记录到67个单位放电可被电刺激中缝大核(NRM)所逆行兴奋。其中有7个单位为呼吸相关性单位(吸气性6、呼气性1),占脑桥87个呼吸相关性单位总数的8％。逆行兴奋潜伏期在0.4—2.5ms之间,平均1.2ms。中缝大核内微量注入麦角辣根过氧化酶(WGA-HRP)后在NPBM-KF区观察到大量HRP标记神经元。本实验结果表明,发自脑桥呼吸调整中枢神经元的轴突可投射到中缝大核。这一投射通路可能与呼吸及痛觉调节有关。     

Henipaviruses and lyssaviruses target nucleolar treacle protein and regulate ribosomal RNA synthesis

The nucleolus is a common target of viruses and viral proteins, but for many viruses the functional outcomes and significance of this targeting remains unresolved. Recently, the first intranucleolar function of a protein of a cytoplasmically-replicating negative-sense RNA virus (NSV) was identified, with the finding that the matrix (M) protein of Hendra virus (HeV) (genus Henipavirus, family Paramyxoviridae) interacts with Treacle protein within nucleolar subcompartments and mimics a cellular mechanism of the nucleolar DNA-damage response (DDR) to suppress ribosomal RNA (rRNA) synthesis. Whether other viruses utilise this mechanism has not been examined. We report that sub-nucleolar Treacle targeting and modulation is conserved between M proteins of multiple Henipaviruses, including Nipah virus and other potentially zoonotic viruses. Furthermore, this function is also evident for P3 protein of rabies virus, the prototype virus of a different RNA virus family (Rhabdoviridae), with Treacle depletion in cells also found to impact virus production. These data indicate that unrelated proteins of viruses from different families have independently developed nucleolar/Treacle targeting function, but that modulation of Treacle has distinct effects on infection. Thus, subversion of Treacle may be an important process in infection by diverse NSVs, and so could provide novel targets for antiviral approaches with broad specificity.     

流式细胞术的发展及在植物研究中的应用

流式细胞术是通过对液流中各种荧光标记的颗粒进行多参数快速高效的定性或定量测定的方法,在科学研究的多个领域发挥重要作用。然而,由于植物组织及细胞壁和次生代谢产物等细胞的特殊成分和结构,限制了其在植物研究领域的应用。本文在介绍流式细胞仪发展和组成分类的基础上,着重讨论了流式细胞术在植物领域的应用、研究进展及应用限制,进而展望该研究领域的发展趋势,为拓宽植物流式细胞术的潜在应用范围提供新的思考方向。     

The plant nucleus in mycorrhizal roots: positional and structural modifications

Summary— Positional and structural modifications were demonstrated in nuclei of leek cells, after establishment of a symbiosis with two vesicular-arbuscular fungi, Glomus versiforme and Glomus E₃. By combining light, immuno-electron microscopy and morphometry, the fungi were shown to have a direct effect on the host nuclear morphology: the effect was confined to a specific plant tissue (the cortical parenchyma) and to a moment of the fungal morphogenesis (the arbuscule). When they branch to form the complex structures called arbuscules in the inner parenchyma cells, the host nucleus migrates from the periphery of these cells towards their centre. In addition, it becomes larger and lobed, with a decondensed chromatin. A monoclonal antibody that mostly binds to the condensed chromatin revealed a significant decrease in gold labelling intensity over the nuclei of the colonized cells. These modifications suggest that the nuclear migration and the changes in chromatin organization are related to the modifications in gene expression observed during the establishment of mycorrhizal symbiosis.     

Composition of nuclear dense bodies and nucleolus-associated bodies in interphase nuclei of the unicellular green alga Chlamydomonas reinhardtii

Summary— The interphase nucleus of the green alga, Chlamydomonas reinhardtii, displayed two types of bodies some of them, the dense bodies, lying apparently free in the nucleoplasm while the others were attached to the nucleolus and were, therefore, referred to as nucleolus-associated bodies (NABs). The presence of DNA, RNA and histones in dense bodies was investigated by means of post-embedding immunocytochemistry and cytochemistry using a monoclonal antibody to single and double stranded DNA, a polyclonal antibody to rye H3 histones and RNase A-gold complexes. The dense bodies were shown to contain significant amounts of RNA but neither DNA nor histones were detected; their composition was thus similar to that of the dense bodies described in higher plant cells. We propose that dense bodies might be implicated in the assembly of the 25 to 45 nm granules observed throughout the nucleoplasm of Chalamydomonas interphase nuclei. The composition of NABs was found to be distinct from that of the dense bodies since they were labeled by the antibody to DNA, specially in cryofixed and cryosubstituted specimens. The presence of DNA in NABs together with their intimate association to the nucleolus suggest that they may correspond to specific segments of chromosomes.     

Uptake and Release of d-Aspartate, GABA, and Glycine in Guinea Pig Brainstem Auditory Nuclei

Abstract: This study attempts to determine if the medial (MSO) and lateral superior olive (LSO), medial nucleus of the trapezoid body (MNTB), ventral nucleus of the lateral lemniscus (VNLL), and central nucleus of the inferior colliculus (ICc) contain glutamatergic synaptic endings. Micropunch and microdissection procedures provided fresh samples of these auditory nuclei for the measurement of the high-affinity uptake and electrically evoked release of exogenous d -[³H]ASP. The study also determined if the LSO and MSO contain glycinergic synaptic endings by measuring uptake and release of [¹⁴C]-Gly in these nuclei, and whether the MNTB, VNLL, and ICc contain GABAergic endings by assessing the uptake and release of [¹⁴C]GABA in these structures. Several strategies optimized the evoked Ca²⁺-dependent release of the labeled amino acids. These included the enhancement of high-affinity uptake during loading of the markers into the tissues, inhibition of uptake during the subsequent measurement of release, and use of an electrical stimulus current that evoked maximal Ca²⁺-dependent release. Each of these nuclei manifested the high-affinity uptake and the evoked Ca²⁺-dependent release of d -[³H]Asp, suggesting the presence of synaptic endings that may use Glu or Asp as a transmitter. Similar findings suggest the presence of glycinergic synaptic endings in the LSO and MSO, and of GABAergic synaptic endings in the MNTB, VNLL, and ICc.     

Evidence for Glutamatergic Projections from the Cochlear Nucleus to the Superior Olive and the Ventral Nucleus of the Lateral Lemniscus

Abstract: This study attempts to determine if projections ascending from the guinea pig cochlear nucleus (CN) could be glutamatergic and/or aspartatergic. Multiple radio frequency lesions were made to ablate the right CN. The ablation was verified histologically. To identify the principal targets of CN efferents, silver impregnation methods were used to localize the preterminal degeneration of fibers in transverse sections of the brainstem 5 and 7 days after CN ablation. CN efferents projected heavily to the lateral superior olive (LSO) ipsilaterally, the medial superior olive (MSO) bilaterally, and contralaterally to the medial (MNTB) and ventral (VNTB) nuclei of the trapezoid body, the ventral (VNLL) and intermediate nuclei of the lateral lemniscus and the central nucleus of the inferior colliculus (ICc). There were smaller projections to the lateral nucleus of the trapezoid body ipsilaterally, the dorsal and dorsomedial periolivary nuclei bilaterally, and the dorsal nucleus of the lateral lemniscus contralaterally. There were sparse projections to the VNLL and ICc ipsilaterally and the CN contralaterally, and a very sparse projection to the contralateral LSO. To determine if CN efferents were glutamatergic and/or aspartatergic, the fresh brainstem was sectioned transversely and samples of the LSO, MSO, MNTB, VNLL, and ICc were taken to measure the electrically evoked release and the uptake of d -[³H]Asp and [¹⁴C]Gly or [¹⁴C]GABA 3–5 days after the CN ablation. The release studies suggest that only certain of the histologically identified projections ascending from the CN may be glutamatergic and/or aspartatergic. CN ablation depressed d -[³H]Asp release in the MSO bilaterally and in the contralateral MNTB and VNLL, suggesting that the CN efferents to these nuclei may use glutamate or aspartate as a transmitter. It was unclear whether a marginal depression of d -[³H]Asp release in the ipsilateral LSO reflected the presence of glutamatergic CN projections to this nucleus. d -[³H]Asp release in the ICc was unaffected, suggesting that CN efferents to this nucleus may not be glutamatergic. There were no deficits in d -[³H]Asp uptake. [¹⁴C]Gly release from the LSO and MSO was unchanged. [¹⁴C]Gly uptake was unchanged in the MSO and depressed only in the contralateral LSO, possibly reflecting subnormal uptake activity in endings contributed by contralateral MNTB cells that had lost their CN efferents. [¹⁴C]GABA uptake in the MNTB, VNLL, and ICc was unchanged. [¹⁴C]GABA release was unchanged in the VNLL and ICc. [¹⁴C]GABA release was depressed only in the contralateral MNTB, possibly reflecting the loss of a small complement of GABAergic CN efferents and the reaction of GABAergic projections from the contralateral VNTB to their loss of CN efferents.     

中缝核提取液对体外培养的中脑黑质神经元存活和生长的影响

中脑黑质是中缝核５－ＨＴ神经元最早期的靶组织之一。为了分析神经元对其靶细胞的作用是受某种特异性蛋白或神经营养因子的影响,本文用中缝核提取液作用于体外培养的中脑黑质神经元,证明了该提取液能促进中脑黑质神经元的存活和生长,其活性部分是分子量大于３０ｋＤ的组份,经ＳＤＳ－聚丙烯酰胺梯度凝胶电泳,呈现一条主带,分子量在４３ｋＤ左右。     

大鼠延髓腹外侧表面呼吸调节化学感受区的感受机制分析

用免疫组化（ＨＲＰ）、Ｈ＾＋表面透入、核团微量注射、微电泳及损毁等方法探讨了延髓腹侧表面中枢化学感受机制。结果表明它与其浅层核团：斜方体核、外周橄榄腹外侧核（ＬＶＰＯ）、斜方体后核、巨细胞旁外侧核和外侧网状核等有神经结构联系。表面Ｈ＾＋可能被上述核团的突起或胞体感受。非呼吸相关神经元（ＬＶＰＯ）与呼吸相关神经元,同样可能参与中枢化学感受而调节呼吸活动。