Piperidine increase in the brain of dormant mice

During a 2-hour period of dormancy (sleep), piperidine is accumulated in the mouse brain.     

Experimental evidence that competition promotes divergence in adaptive radiation

Interspecific competition driving divergence in adaptive radiation has not previously been tested experimentally. Natural selection on a morphologically variable species of stickleback fish was contrasted in the presence and absence of a close relative. Selection was nondirectional when the target species was alone, whereas addition of the second species favored individuals most different from it morphologically and ecologically. Disproportionately severe competition between similar phenotypes indicates frequency-dependent selection, verifying a crucial element of theory of competition and character divergence. The findings help resolve outstanding debates on the ecological causes of diversification and the evolutionary consequences of competitive interactions.     

数据仓库中休眠数据管理的研究

随着时间的推移,数据仓库中会产生大量休眠数据,严重影响其性能.本文从休眠数据的产生、识别和处理三个方面进行研究,取得较好效果并维持数据仓库的性能不会下降.     

休眠期内甜樱桃不同品种枝条的抗寒性

为筛选抗寒性较强的甜樱桃品种,在休眠期内,以4个甜樱桃品种为试材,对枝条的相对电导率、超氧化物歧化酶(SOD)、过氧化物酶(POD)、可溶性蛋白、脯氨酸和丙二醛(MDA)等进行测定,利用它们与抗寒性的相关性探讨甜樱桃品种抗寒性的强弱。结果表明:在4个甜樱桃品种中,‘龙冠’的相对电导率和丙二醛含量均低于其他3个品种,SOD、POD酶活性、可溶性蛋白、脯氨酸含量均高于其他3个品种,表现出较强的抗寒性,‘龙宝’、‘红蜜’次之,‘龙丹’的抗寒性最弱。     

不同秋眠级别紫花苜蓿引种试验

本研究进行了不同秋眠级别 (2～ 9级 )的 13个紫花苜蓿品种引种试验 ,研究表明 :秋眠级别为 2的紫花苜蓿品种由于年产草量极低 ,不适于在长江中下游地区推广种植 ;而半秋眠型和秋眠型的品种产草量较高 ,均适于长江中下游地区种植 ;秋眠级别为 7级的CS70D表现最突出 ,可年产干草约 112 6 7kg 6 6 7m2 ,从而为长江中下游集约农区紫花苜蓿产业化生产提供借鉴     

BclGs对肿瘤细胞促凋亡功能的初步研究

为了探讨仅含有BH3结构域的促凋亡蛋白BclGs的促凋亡机理,从人睾丸cDNA文库中克隆BclGs基因编码区,将其与pEGFP-C1载体连接,构建载体pEGFP-BclGs,转染COS7细胞和多种肿瘤细胞(如Hela、HepG2和MCF7等),研究BclGs对肿瘤细胞的促凋亡功能。结果表明,pEGFP-BclGs可以诱导不同的肿瘤细胞凋亡,但凋亡率存在差别;BclGs在不同细胞的线粒体中均呈点状分布。线粒体是诱导肿瘤细胞凋亡的有效细胞器,BclGs在线粒体中呈点状分布。     

Raman microprobe evidence for lignin orientation in the cell walls of native woody tissue

Raman microprobe spectra from the secondary wall of earlywood tissue from Picea mariana (black spruce) reveal evidence of the orientation of lignin relative to the plane of the cell wall. In most instances, the aromatic rings of the phenyl propane structural units are parallel to the plane of the cell-wall surface.     

Effects of regulators on the respiratory enzyme of pear branches during dormant period

The effects of regulators on the respiratory enzymes of Qiyuesu’s pear branches during dormant period were studied. The results showed that enzyme activities of SDH, G-6-PDH and 6-PGDH were increased by 0.02 mmol/L SA and 120 mg/L GA₃. The enzyme activities of phosphohexoisomerase were reduced by 0.02 mmol/L SA and 120 mg/L GA₃. Compared with the control, the PGI activity was reduced by 20.5% and 13.6% using 0.02mmol/L SA and 120mg/L GA₃. Similarly, the SDH activity was increased by 6.1% and 29.2%, respectively. Likewise, the activity of G-6-PDH and 6-PGDH was increased by 93.9% and 24.8%. Changes of respiratory enzymes were consistent with respiratory pathway of regulators, which indicated that SA and GA₃ were helpful to break the dormancy by enhancing activities of SDH, G-6-PDH and 6-PGDH.     

Knockdown of the Meq gene in Marek's disease tumor cell line MSB1 might induce cell apoptosis and inhibit cell proliferation and invasion

Marek's disease (MD), a highly cell-associated and contagious disease of chickens caused by Marek's disease virus (MDV) can result in neural lesions, immunosuppression and neoplasia in chicken. The Meq gene is an important oncogene in the MDV genome, and it is expressed highly in MD tumor tissues and MD T-lymphoblastoid cell lines. An experiment was conducted to elucidate the role of Meq in MD tumor transformation. RNA interference technology was used to block its expression, and then analyzed the biological effects of Meq knockdown on the MD tumor cell line MSB1. A small interfering RNA with an interference efficiency of 70% (P<0.01) was transfected into MSB1 cells to knock down the expression of Meq gene. The cell proliferation, cycle and apoptosis were detected post-Meq knockdown. The results showed that MSB1 cell proliferation was downregulated remarkably at 48 h (P<0.01), 60 h (P<0.05) and 72 h (P<0.01) post-Meq knockdown. The cell cycle was unaffected (P>0.05). B-cell lymphoma 2 gene (BCL2) was anti-apoptotic and caspase-6 was the effector in the apoptosis pathway. The activity of caspase-6 was upregulated (P<0.05) significantly and BCL2 gene expression was downregulated (P<0.05) significantly post-Meq knockdown, suggesting cell apoptosis might be induced. MSB1 cell migration did not exhibit any obvious change (P>0.05) post-Meq knockdown, but the expression of two genes (matrix metalloproteinase 2 (MMP2) and MMP9) that are correlated closely to cell invasion was downregulated (P<0.05) remarkably post-Meq knockdown. The Meq knockdown might affect the main features of tumorous cells, including proliferation, apoptosis, and invasion, suggesting that the Meq gene might play a crucial role in interfering with lymphomatous cell transformation.     

CAR-T细胞免疫疗法在肿瘤治疗中的研究进展

嵌合抗原受体T细胞免疫疗法(chimeric antigen receptor therapy,CAR-T)作为一种肿瘤免疫治疗方法,具有良好的治疗前景.该文总结了CAR-T细胞治疗的发展历程与临床研究进展,阐述了CAR-T细胞治疗耐药机制,并提出了优化CAR-T细胞治疗的策略.     

一种果梅休眠枝韧皮部DNA提取方法

以5个果梅品种的休眠枝韧皮部为材料,采用改良CTAB法提取其基因组总DNA,并与其相应幼叶的DNA提取效果进行比较.结果表明:该方法从5个果梅品种的休眠枝韧皮部中均能提取出基因组总DNA,且DNA具有较高的纯度和完整性,5个品种的D260nm/D280,nm比值为1.8～2.0,无降解现象,RNA去除干净,能被限制性内...     

Effects of growth regulators on the respiration metabolism of pear buds during dormant period

The effects of growth regulators on the respiration metabolism of pear buds during dormant period were studied in this experiment. The results showed that, during early dormant period, the respiration intensity of pear buds was infirm and increased slowly. As the weather became very cold, the respiration intensity rapidly declined, and after that it changed a little. In the later stage of dormant period, the respiration intensity rose rapidly. The maximum value appeared on January 4th, at 0.390 mo1 O₂·g⁻¹ FW·min⁻¹, but thereafter declined to its original level. Under natural conditions, three respiratory pathways showed different changes. Pentose phosphate pathway might be the main reason for dormancy release in pear buds. The exogenous gibberellins were more efficient than salicylic acid in increasing the respiration rate. The exogenous SA appeared to play a more important role than exogenous GA₃ in phosphopentose pathway. The effect of gibberellins would be more effective than SA in tricarboxylic acid cycle (TCA). The respiration rate of glycolysis was not affected by gibberellins and salicylic acid.     

Experimental evidence for spatial self-organization and its emergent effects in mussel bed ecosystems

Spatial self-organization is the main theoretical explanation for the global occurrence of regular or otherwise coherent spatial patterns in ecosystems. Using mussel beds as a model ecosystem, we provide an experimental demonstration of spatial self-organization. Under homogeneous laboratory conditions, mussels developed regular patterns, similar to those in the field. An individual-based model derived from our experiments showed that interactions between individuals explained the observed patterns. Furthermore, a field study showed that pattern formation affected ecosystem-level processes in terms of improved growth and resistance to wave action. Our results imply that spatial self-organization is an important determinant of the structure and functioning of ecosystems, and it needs to be considered in their conservation.     

Regulation of cell migration by the C2 domain of the tumor suppressor PTEN

PTEN is a tumor suppressor protein that dephosphorylates phosphatidylinositol 3,4,5 trisphosphate and antagonizes the phosphatidylinositol-3 kinase signaling pathway. We show here that PTEN can also inhibit cell migration through its C2 domain, independent of its lipid phosphatase activity. This activity depends on the protein phosphatase activity of PTEN and on dephosphorylation at a single residue, threonine(383). The ability of PTEN to control cell migration through its C2 domain is likely to be an important feature of its tumor suppressor activity.     

细胞焦亡调控肿瘤免疫微环境的分子机制研究进展

为探究细胞焦亡在肿瘤免疫微环境中的分子机制,收集国内外最新文献资料,对小动物肿瘤现状、细胞焦亡、诱导细胞焦亡的蛋白家族和其在肿瘤免疫微环境中的作用机制进行阐述。结果表明:1)细胞焦亡是由Gasdermins(GSDMs)家族蛋白所介导的可调节的细胞程序性死亡,GSDMs被蛋白酶水解激活,切割形成N端(具有成孔活性),在细胞膜上打孔,导致渗透性细胞裂解,从而将促炎分子释放到细胞外,引发炎症和免疫反应,对肿瘤微环境的调节有重要意义;2)细胞发生焦亡时会不断胀大破裂,释放细胞内容物,其产生的炎性环境可以招募细胞毒性T细胞(CD8+T)、巨噬细胞和NK细胞等免疫细胞杀死和吞噬肿瘤细胞,抑制髓源性抑制细胞(MDSC);3)细胞焦亡将肿瘤免疫微环境激活为免疫刺激状态,使其由“冷”转“热”,抑制肿瘤细胞的增殖、侵袭、转移,靶向治疗肿瘤疾病,降低患病宠物的死亡率。综上,诱导细胞焦亡和调控肿瘤免疫微环境为抗肿瘤治疗提供了新思路,细胞焦亡分子生物学机制的深入研究有望为宠物临床提供一种前景广阔的新型治疗方法。