The Regulation of Exogenous Jasmonic Acid on UV-B Stress Tolerance in Wheat

Enhanced ultraviolet-B radiation (UV-B, 280?C320?nm) is recognized as one of the environmental stress factors that cannot be neglected. Jasmonic acid (JA) is an important signaling molecule in a plant??s defense against biotic and abiotic stresses. To determine the role of exogenous JA in the resistance of wheat to stress from UV-B radiation, wheat seedlings were exposed to 0.9?kJ?m^?2?h^?1 UV-B radiation for 12?h after pretreatment with 1 and 2.5?mM JA, and the activity of antioxidant enzymes, the level of malondialdehyde (MDA), the content of UV-B absorbing compounds, photosynthetic pigments, and proline and chlorophyll fluorescence parameters were measured. The results of two-way ANOVA illustrated that the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), MDA level, anthocyanin and carotenoid (Car) content, and almost all chlorophyll fluorescence parameters were significantly affected by UV-B, JA, and UV-B?×?JA (P?<?0.05) [the maximal efficiency of photosystem II photochemistry (F _v/F _m) was not affected significantly by UV-B radiation]. Duncan??s multiple-range tests demonstrated that UV-B stress induced a significant reduction in plant photosystem II (PSII) function and SOD activity and an increased level of membrane lipid peroxidation, indicative of the deleterious effect of UV-B radiation on wheat. JA pretreatment obviously mitigated the detrimental effect of UV-B on PSII function by increasing F _v/F _m, reaction centers?? excitation energy capture efficiency (F _v??/F _m??), effective photosystem II quantum yield (??PSII), and photosynthetic electron transport rate (ETR), and by decreasing nonphotochemical quenching (NPQ) of wheat seedlings. Moreover, the activity of SOD and the content of proline and anthocyanin were provoked by exogenous JA. However, the MDA level was increased and Car content was decreased by exogenous JA with or without the presence of supplementary UV-B, whereas the contents of chlorophyll and flavonoids and related phenolics were not affected by exogenous JA. Meanwhile, exogenous JA resulted in a decrease of CAT and POD activities under UV-B radiation stress. These results partly confirm the hypothesis that exogenous JA could counteract the negative effects of UV-B stress on wheat seedlings to some extent.     

CD38/cADPR/Ca2+ Pathway Promotes Cell Proliferation and Delays Nerve Growth Factor-induced Differentiation in PC12 Cells

Intracellular Ca²⁺ mobilization plays an important role in a wide variety of cellular processes, and multiple second messengers are responsible for mediating intracellular Ca²⁺ changes. Here we explored the role of one endogenous Ca²⁺-mobilizing nucleotide, cyclic adenosine diphosphoribose (cADPR), in the proliferation and differentiation of neurosecretory PC12 cells. We found that cADPR induced Ca²⁺ release in PC12 cells and that CD38 is the main ADP-ribosyl cyclase responsible for the acetylcholine (ACh)-induced cADPR production in PC12 cells. In addition, the CD38/cADPR signaling pathway is shown to be required for the ACh-induced Ca²⁺ increase and cell proliferation. Inhibition of the pathway, on the other hand, accelerated nerve growth factor (NGF)-induced neuronal differentiation in PC12 cells. Conversely, overexpression of CD38 increased cell proliferation but delayed NGF-induced differentiation. Our data indicate that cADPR plays a dichotomic role in regulating proliferation and neuronal differentiation of PC12 cells.Mobilization of intracellular Ca²⁺ stores is involved in diverse cell functions, including fertilization, cell proliferation, and differentiation (1–4). At least three endogenous Ca²⁺-mobilizing messengers have been identified, including inositol trisphosphate (IP₃),³ nicotinic adenine acid dinucleotide phosphate (NAADP), and cyclic adenosine diphosphoribose (cADPR). Similar to IP₃, cADPR can mobilize calcium release in a wide variety of cell types and species, from protozoa to animals. The cADPR-mediated Ca²⁺ signaling has been indicated in a variety of cellular processes (5–7), from abscisic acid signaling and regulation of the circadian clock in plants, to mediating long-term synaptic depression in hippocampus.Ample evidence shows that the ryanodine receptors are the main intracellular targets for cADPR (1, 2, 8). Ryanodine receptors (RyRs) are intracellular Ca²⁺ channels widely expressed in various cells and tissues, including muscles and neurons. It is the major cellular mediator of Ca²⁺-induced Ca²⁺ release (CICR) in cells. There are three isoforms of ryanodine receptors: RyR1, RyR2, and RyR3, all of which have been implicated in the cADPR signaling (1, 2, 8). However, evidence regarding cADPR acting directly on the receptors is lacking (9). It has been suggested that accessory proteins, such as calmodulin and FK506-binding protein (FKBP), may be involved instead (10–15).cADPR is formed from nicotinamide adenine dinucleotide (NAD) by ADP-ribosyl cyclases. Six ADP-ribosyl cyclases have been identified so far: Aplysia ADP-ribosyl cyclase, three sea urchin homologues (16, 17), and two mammalian homologues, CD38 and CD157 (18). CD38 is a membrane-bound protein and the main mammalian ADP-ribosyl cyclase. As a novel multifunctional enzyme, CD38 catalyzes the synthesis and hydrolysis of both cADPR and NAADP, two structurally and functionally distinct Ca²⁺ messengers. Virtually all mammalian tissues ever examined have been shown to express CD38. CD38 knock-out mice exhibit multiple physiological defects, ranging from impaired immune responses, metabolic disturbances, to behavioral modifications (1, 6, 18).CD38 was originally identified as a lymphocyte differentiation antigen (18). Indeed, CD38/cADPR has been linked to cell differentiation (5). For example, in human HL-60 cells, CD38 expression and the consequential accumulation of cADPR play a causal role in mediating granulocytic differentiation (19). In addition, expression of CD38 in HeLa and 3T3 cells not only increased intracellular Ca²⁺ concentration but also induced cell proliferation by significantly reducing the S phase duration, leading to shortened cell doubling time (20). The ability of cADPR to increase cell proliferation has also been observed in human T cells (21), human hemopoietic progenitors (22), human peripheral blood mononuclear cells (23), human mesenchymal stem cells (24), and murine mesangial cells (25).The PC12 cell line was derived from rat adrenal medulla and has been used extensively as a neuronal model, since it exhibits many of the functions observed in primary neuronal cultures (26). Most importantly, PC12 cells can be induced by nerve growth factor (NGF) to differentiate into cells with extensive neurite outgrowths, resembling neuronal dendritic trees (26, 27). In contrast to NGF, numerous growth factors and neurotransmitters can induce the proliferation of PC12 cells instead (26). Both IP₃ receptor- and ryanodine receptor-mediated Ca²⁺ stores have been shown to be present in PC12 cells (28–31). The type 2 ryanodine receptor is expressed in PC12 cells and activation of the NO/cGMP pathway in PC12 cells results in calcium mobilization, which is mediated by cADPR and similar to that seen in sea urchin eggs (32). It has been demonstrated that NAADP, another Ca²⁺-mobilizing messenger, is also a potent neuronal differentiation inducer in PC12 cells, while IP₃ exhibits no such role (33, 34). Whether cADPR is involved in the proliferation and differentiation of PC12 cells is unknown.Here we show that activation of the CD38/cADPR/Ca²⁺ signaling is required for the ACh-induced proliferation in PC12 cells, while inhibition of the pathway accelerates NGF-induced neuronal differentiation. Our data indicate that cADPR is important in regulating cell proliferation and neuronal differentiation in PC12 cells.     

Molecular phylogeny and taxonomic reconsideration of the subfamily Zapodinae (Rodentia: Dipodidae), with an emphasis on Chinese species

Although the subfamily Zapodinae (Rodentia, Dipodidae) contains only five species, the phylogeny and taxonomy of these species are still being disputed. First, whether Eozapus and Napaeozapus should be treated as independent genera or subgenera of Zapus has been argued for a long period. Second, the subspecific genetic differentiation of Chinese jumping mouse (Eozapus setchuanus) has not been studied in detail, neither from morphological nor molecular aspects. In this study, the phylogenetic relationship among all the five species of Zapodinae was reconstructed using DNA sequence data from the mitochondrial cytochrome b gene and the nuclear interphotoreceptor retinoid binding protein gene. Bayesian inference, maximum parsimony and maximum likelihood analyses were conducted. The results showed that two major clades could be recognized within Zapodinae. Eozapus setchuanus, is the species endemic to China, strongly formed a monophyletic clade. In the other clade, genus Zapus received significant support in all analyses to be the sister group of the genus Napaeozapus. By comparing genetic distances among these three genera, we conclude that both Eozapus and Napaeozapus should be considered as valid genera rather than subgenera of Zapus. Furthermore, we observed that the two subspecies of E. setchuanus did not form reciprocally monophyletic groups, thus the traditional taxonomy which divided E. setchuanus into two subspecies based on only one morphological character was questionable.     

Further Daphniphyllum Alkaloids with Insecticidal Activity from the Bark of Daphniphyllum macropodum Miq.

Two new Daphniphyllum alkaloids, macropodumines J and K ( 1 and 2 , resp.), together with six known structurally related alkaloids, 3 – 8 , were isolated from the bark of Daphniphyllum macropodum Miq . The structures of the new compounds 1 and 2 were elucidated on the basis of a comprehensive analysis of their spectroscopic and chemical data. Macropodumine J ( 1 ) contains a CN group which is relatively rare in naturally occurring alkaloids. All isolated compounds were tested for their insecticidal activities against a number of insect species. Daphtenidine C ( 5 ) is the most active compound against Plutella xylostella. This is the first report of insecticidal properties of Daphniphyllum alkaloids.     

抑制肿瘤生长活性的内皮生长抑制剂EDI-8t

对内源性的内皮生长抑制剂的序列来源分析后,用RT-PCR方法从人脐带中获得了417bp的cDNA,并克隆到毕赤酵母表达载体pPIC9,然后转化毕赤酵母GS115获得重组表达菌株。表达菌株通过甲醇诱导表达后,将发酵液通过分离纯化获得重组蛋白纯品,命名为EDI-8t。体外实验结果表明,这个胶原蛋白VIII来源的rhEDI-8t蛋白能特异性地抑制牛主动脉内皮细胞的增殖和迁移,并能引起内皮细胞的凋亡。动物体内实验结果表明,rhEDI-8t蛋白样品可有效抑制裸鼠皮下肝癌肿瘤的生长,抑制效果和参照品endostatin相同。但在小鼠黑色素瘤肺转移模型中,rhEDI-8t显示了高于参照品的抑癌效果。     

鼠肝中金属硫蛋白的纯化

旨在探索鼠肝中金属硫蛋白(MT)提取工艺并加以改进。按照经典方法工艺提取MT,用中空纤维柱超滤方法加以改进,依据MT自身特点进行分离和鉴定。结果显示,粗品符合MT特点:分子量在6.5kD左右;无280nm特征吸收峰,加酸后紫外吸收(200-300nm)肩峰消失;通过离子交换可以实现MT1、MT2的分离;通过原子吸收测定,含有锌、铜、镉3种金属,锌含量最高,具有重要的病理生理意义。因此,与其它方法比较,改进后方法更适宜实验室制备。     

PRPF6 promotes androgen receptor/androgen receptor-variant 7 actions in castration-resistant prostate cancer cells

Androgen receptor (AR) and its variants play vital roles in development and progression of prostate cancer. To clarify the mechanisms involved in the enhancement of their actions would be crucial for understanding the process in prostate cancer and castration-resistant prostate cancer transformation. Here, we provided the evidence to show that pre-mRNA processing factor 6 (PRPF6) acts as a key regulator for action of both AR full length (AR-FL) and AR variant 7 (AR-V7), thereby participating in the enhancement of AR-FL and AR-V7-induced transactivation in prostate cancer. In addition, PRPF6 is recruited to cis-regulatory elements in AR target genes and associates with JMJD1A to enhance AR-induced transactivation. PRPF6 also promotes expression of AR-FL and AR-V7. Moreover, PRPF6 depletion reduces tumor growth in prostate cancer-derived cell lines and results in significant suppression of xenograft tumors even under castration condition in mouse model. Furthermore, PRPF6 is obviously highly expressed in human prostate cancer samples. Collectively, our results suggest PRPF6 is involved in enhancement of oncogenic AR signaling, which support a previously unknown role of PRPF6 during progression of prostate cancer and castration-resistant prostate cancers.     

舟山海域大中型浮游动物群落时空变化及受控要素

为更好地保护舟山海域的渔业资源和生态环境,了解舟山海域浮游动物组成的时空变化,于2014年到2017年对舟山海域33个站位开展4个季节的生态综合调查,结果表明:4个航次共鉴定出浮游动物成体88种和浮游幼体19类,优势种共12种,浮游动物的优势种更替和群落特征季节变化明显,春夏、夏秋、秋冬、冬春相邻季节优势种更替率分别为75%、80%、100%和60%;平均生物量为夏季(176.34 mg/m³)>春季(120.20 mg/m³)和秋季(86.28 mg/m³)>冬季(7.21 mg/m³);平均丰度为夏季(143.97个/m³)>春季(86.30个/m³)>秋季(21.38个/m³)和冬季(26.86个/m³);平均多样性指数:夏季(3.03)>秋季(2.82)>春季(2.05)>冬季(1.71)。舟山海域浮游动物群落具有明显的季节和区域差异,温度、盐度、Chl a和营养盐是影响舟山浮游动物群落时空变化的主要环境因素,其中春季浮游动物群落空间分布主要受盐度的影响,夏季主要受温度、盐度和Chl a的影响,秋季主要受Chl a的影响,冬季主要受悬浮物和溶解氧的影响,而营养盐对每个季节的浮游动物群落分布都有一定的影响。     

匙叶紫菀,中国菊科一未详知种的补充描述

报道中国菊科紫菀属一未详知种:匙叶紫菀(Aster spathulifolius Maxim.),发现于我国东海的舟山群岛,位于浙江嵊泗县的两个岛上,生于海滨岩石上,并提供特征描述和图片.该种与普陀狗娃花[Aster arenarius(Kitam.)Nemoto]比较近缘,提供了这2种的详细形态区别特征.