绒毛番龙眼对生长光强的形态和生理适应

在100％、50％、25％和8％自然光强下栽培绒毛番龙眼幼苗并研究了其对光环境的适应。100％生长光强下绒毛番龙眼通过增大叶片悬挂角(midrib angle,MA)和比叶重(lamina mass per unit area,LMA),减少叶氮在捕光组分中的分配等降低光能捕获;通过增加类胡萝卜素含量增加热耗散。虽如此,还是发生了比较严重的光抑制,加之叶氮在光合机构中的分配最少,导致光合能力最低,长势最差。8％生长光强下绒毛番龙眼通过降低MA、LMA以及叶片技转,增加叶氮在捕光组分中的分配等提高光能捕获能力,光能转换及利用效率较高,热耗散水平较低,但由于环境光较弱,限制了光合碳同化,植株生长也较慢。50％和25％生长光强下绒毛番龙眼有较强的光能捕获、利用和耗散能力,在几种光处理中长势最好。     

Binding of intravenously injected antibodies against laminin to developing and mature endocrine glands

Summary To determine whether circulating antibodies against laminin can bind in vivo to basement membranes within endocrine glands, affinity-purified sheep or rabbit anti-laminin IgG was intravenously injected into rats. One to five hours after injection, anti-laminin IgG was bound to all basement membranes of adrenal and anterior pituitary glands of mature as well as 2-day-old newborn rats as shown by immunofluorescence microscopy. After the injection of anti-laminin conjugated directly to horseradish peroxidase (HRP), HRP reaction product was also present throughout adrenal and pituitary basement membranes in mature and immature glands 1–5 h post-injection. Ultrathin Lowicryl sections from rats that received unconjugated rabbit anti-laminin IgG 1 h prior to fixation with paraformaldehyde were labeled directly with anti-rabbit IgG-colloidal gold. In these cases, gold also bound specifically over the lamina densa and lamina rara. When adrenal or pituitary glands from mature rats were examined by immunofluorescence 1 week after the injection of sheep anti-laminin IgG, the patterns and amounts of bound sheep IgG were indistinguishable from those observed 1 h after injection. In contrast, significantly less fluorescence was present in glands from 7-day-old rat pups that had received anti-laminin IgG 5 days earlier. In addition, when anti-laminin IgG-HRP was injected into newborns and glands were fixed 5 days later, lengths of labeled endothelial and epithelial basement membranes were often interspersed with unlabeled lengths in zones of cellular proliferation in the outer adrenal cortex and throughout the pituitary gland. These results indicated that unlabeled basement membranes in these regions were probably assembled after the injection of anti-laminin IgG, which would also explain diminished labeling of basement membranes in these animals. Despite the continued presence of heterologous anti-laminin IgG within endocrine basement membranes, however, rat IgG, rat C3, inflammatory cells, or histologic abnormalities were observed in neither newborn nor adult glands under the conditions examined here. Sections from rats injected with control IgG or control IgG-HRP were entirely negative by immunofluorescence, immunoperoxidase, and immunogold techniques. We therefore conclude that (1) apparently large amounts of circulating anti-laminin IgG can bind to adrenal and pituitary basement membranes, and (2) at least some of these basement membranes are assembled during development by progressive splicing of newly synthesized matrix into that already present.     

The Genomic Code: A Pervasive Encoding/Molding of Chromatin Structures and a Solution of the “Non‐Coding DNA” Mystery

Recent investigations have revealed 1) that the isochores of the human genome group into two super‐families characterized by two different long‐range 3D structures, and 2) that these structures, essentially based on the distribution and topology of short sequences, mold primary chromatin domains (and define nucleosome binding). More specifically, GC‐poor, gene‐poor isochores are low‐heterogeneity sequences with oligo‐A spikes that mold the lamina‐associated domains (LADs), whereas GC‐rich, gene‐rich isochores are characterized by single or multiple GC peaks that mold the topologically associating domains (TADs). The formation of these “primary TADs” may be followed by extrusion under the action of cohesin and CTCF. Finally, the genomic code, which is responsible for the pervasive encoding and molding of primary chromatin domains (LADs and primary TADs, namely the “gene spaces”/“spatial compartments”) resolves the longstanding problems of “non‐coding DNA,” “junk DNA,” and “selfish DNA” leading to a new vision of the genome as shaped by DNA sequences.     

Tannuaspis,Tuvaspis and Ilemoraspis,endemic osteostracan genera from the Silurian and Devonian of Tuva and Khakassia (USSR)

Three osteostracan genera, Tannuaspis, Tuvaspis and Ilemoraspis, from the Silurian and Devonian of the Autonomous Republic of Tuva and the Autonomous Region of Khakassia (USSR), are revised on the basis of the type material briefly described by Obruchev (1956, 1961, 1964). Tannuaspis bears some resemblances with the Tremataspididae. Tuvaspis may be closely related to Tannuaspis. Finally, there is no evidence of paired fins and cornual processes in Ilemoraspis (neither is there any evidence of their absence). Tannuaspis and Ilemoraspis share some characters which are not found in any other osteostracan: widely separated orbits, very small and oval lateral fields, situated at the same level as the median dorsal field. These resemblances may suggest that these two genera (to which Tuvaspis may be added) form a monophyletic group of osteostracans, which may be endemic to this part of Central Asia.     

不同耐旱性大麦品种叶片发育的研究

选用耐旱性不同的两个大麦品种作为研究对象,分析其叶片结构的异同。结果表明:两个大麦品种的叶片发育可以分为幼叶萌发期、幼叶抽出期、幼叶生长期和叶片成熟期四个阶段,其中在幼叶萌发期,叶片结构无明显差异。经PAS染色,从幼叶生长期开始,耐旱性弱的Moroc 9-75,含淀粉粒的叶肉细胞少,淀粉粒颗粒小; 耐旱性强的HS 41-1,含淀粉粒的叶肉细胞多,淀粉粒颗粒大。遭受干旱胁迫后,两个品种的植株长势明显较弱,叶片短而窄; 表皮细胞角质层变厚,叶片中叶肉细胞变小,叶肉细胞胞间隙变大,叶肉细胞破裂现象增多; PAS染色反应显示,含淀粉粒的叶肉细胞减少,淀粉粒颗粒变小或基本没有; HS 41-1解体的细胞不如Moroc 9-75多。因此,在光镜下,叶片结构的差异,特别是细胞含有的淀粉粒大小与数量的区别,是植物对水分胁迫的一种适应; 同时叶脉对植物刚性的影响较大。     

阔叶红松林3种阔叶树种柄叶性状变异与相关性

叶包括叶片和叶柄,二者在结构和功能上密切相关,探究叶片性状和叶柄性状变异及性状间相关关系的影响因素对了解植物叶水平上的生物量分配策略具有重要意义。该研究以阔叶红松(Pinus koraiensis)林内3种主要阔叶树种白桦(Betula platyphylla)、紫椴(Tilia amurensis)、五角枫(Acer pictum subsp. mono)为研究对象,每个树种选取小树(胸径:1–6 cm)、中等树(胸径:15–20 cm)、大树(胸径:35–45 cm)各10株样树;另针对大树,考虑取样冠层位置对其结果的影响。通过测定叶片面积、叶片干质量、叶柄长和叶柄干质量,主要探讨树种、植株大小和冠层位置(大树)对叶片性状和叶柄性状变异及其性状间相关性的影响。结果显示:(1)树种和植株大小对4个性状均存在显著影响, 3个树种小树的叶柄长和叶柄干质量显著小于大树,紫椴和五角枫小树的叶片干质量也显著小于大树,而白桦和紫椴小树的叶片面积显著大于大树;对于大树,冠层位置对4个性状变异的影响因树种而异。(2)叶片性状和叶柄性状表现为显著的异速生长关系,且3个树种的回归斜率为紫椴>白桦&...     

C5a receptor-targeting ligand-mediated delivery of dengue virus antigen to M cells evokes antigen-specific systemic and mucosal immune responses in oral immunization

Oral mucosal immunization is a feasible and economic vaccination strategy. In order to achieve a successful oral mucosal vaccination, antigen delivery to gut immune inductive site and avoidance of oral tolerance induction should be secured. One promising approach is exploring the specific molecules expressed on the apical surfaces of M cells that have potential for antigen uptake and immune stimulation. We previously identified complement 5a receptor (C5aR) expression on human M-like cells and mouse M cells and confirmed its non-redundant role as a target receptor for antigen delivery to M cells using a model antigen. Here, we applied the OmpH ligand, which is capable of targeting the ligand-conjugated antigen to M cells to induce specific mucosal and systemic immunities against the EDIII of dengue virus (DENV). Oral immunization with the EDIII–OmpH efficiently targeted the EDIII to M cells and induced EDIII-specific immune responses comparable to those induced by co-administration of EDIII with cholera toxin (CT). Also, the enhanced responses by OmpH were characterized as Th2-skewed responses. Moreover, oral immunization using EDIII–OmpH did not induce systemic tolerance against EDIII. Collectively, we suggest that OmpH-mediated targeting of antigens to M cells could be used for an efficient oral vaccination against DENV infection.     

Trichinella spiralis: site selection by the larva during the enteral phase of infection in mice

Mice, belonging to two strains, were infected by the oral route with muscle larvae of Trichinella spiralis. Host animals were killed at various times up to 48 hr after administration of larvae, and the infected small intestines were fixed immediately in 10% neutral formalin. Sections of infected gut, embedded in paraffin and cut at 5 μm, or in methacrylate and cut at 0.5 μm, revealed that all stages (i.e., 1 to 4) of T. spiralis were embedded between the lamina propria and the columnar epithelium. First-stage muscle larvae occupied this niche as early as 10 min after introducing them into the host by the oral route.     

高等哺乳动物LEM结构域蛋白家族的研究进展

在高等动物细胞开放式有丝分裂过程中,细胞核膜会发生高度有序的周期性去组装和装配的动态变化。近年的研究结果表明是LEM家族蛋白成员通过与BAF因子相互作用介导了内核膜、核纤层蛋白以及染色体之间的相互作用。LEM蛋白、核纤层蛋白以及BAF因子直接相互作用形成的三元复合体在结构与功能上是相互依赖的,在此结构与功能上组成的网络体系是形成细胞核的一些基本生物学过程的重要条件。该复合体在调控有丝分裂M期后期和末期染色体的正常分离、有丝分裂后核膜的重组装,细胞分裂间期细胞核及核膜形态维持,调控DNA复制和DNA损伤修复,调节基因表达和信号通路以及逆转录病毒感染等方面发挥着重要的生物学功能。并且LEM蛋白相关基因的异常对核纤层疾病和肿瘤的发生发展具有重要的影响。文章主要针对LEM蛋白家族成员的结构以及功能研究进展进行了详细的综述。