A comparative study of the effects of abscisic acid and methyl jasmonate on seedling growth of rice

The effects of abscisic acid (ABA) and methyl jasmonate (MJ) on growth of rice seedlings were compared. The lowest tested concentration of ABA and MJ that inhibited seedling growth was found to be 4.5 and 0.9 µM, respectively. Growth inhibition by ABA is reversible, whereas that by MJ is irreversible. GA₃ was found to be more effective in reversing inhibition of shoot growth by ABA than by MJ. KCl partially relieved MJ-inhibited, but not ABA-inhibited, growth of rice seedlings. The beneficial effect of K⁺ on growth of rice seedlings in MJ medium could not be replaced by Li⁺, Na⁺ or Cs⁺. MJ treatment caused a marked release of K⁺ into the medium. In order to understand whether cell wall-bound peroxidase activity was inversely related to rice seedling growth, effects of ABA and MJ on cell wall-bound peroxidase activity were also examined. Results indicated that both ABA and MJ increased cell wall-bound peroxidase activity in roots and shoots of rice seedlings. Although MJ (4.5 µM) was less effective in inhibiting root growth than ABA (9 µM), MJ was found to increase more cell wall-bound peroxidase activity in roots than ABA.     

江西省九连山自然保护区的植被

1． 九连山自然保护区位于我国南部的南岭山地东段,处于江西南部,与广东边境相连,北纬24˚31′一24˚39′,东经114˚27′一114˚29′,面积约2000公顷。2．自然保护区内动植物种类极为丰富,其中高等植物1200种以上,约有206科;苔藓植物约30种,蕨类约62种,种子植物1100种以上。脊椎动物100多种。3．动植物区系起源较古老,有许多古代的科属,包括很多残遗种和稀有种。又是我国著名的单种属：观光木属和半枫荷属的家乡。有许多稀有的珍贵动物如：云豹、金猫、豹、华南虎、獐、水鹿、鬣羚、大灵猫、穿山甲、水獭、白鹇、平胸龟等。动物区系上,属于东洋界的华中区。4．自然保护区植被主要有四个群系纲;Ⅰ．常绿阔叶林;Ⅱ．针叶林;Ⅲ．山地草甸;Ⅳ．山地苔藓、矮林;14个群系,约19个群丛。顶极植被为常绿阔叶林。     

不同的下丘脑肽和神经递质对鲤鱼促性腺激素和生长激素分泌活动的影响

以１龄性腺发育中期鲤鱼为材料,采用腹腔（ｉ．ｐ）注射的方法,研究不同的下丘脑肽和神经递质对鲤鱼促性腺激素（ＧｔＨ）和生长激素（ＧＨ）分泌的影响。结果表明：促甲状腺激素释放激素（ＴＲＨ）、Ｌ－多巴（Ｌ－ＤＯＰＡ）、甲基睾酮（ＭＴ）、γ－氨基丁酸（ＧＡＢＡ）、促黄体素释放激素类似物（ＬＨＲＨ－Ａ）和三碘甲状腺原氨酸（Ｔ３）都能显著刺激ＧｔＨ的分泌,但最大效应时间各不相同。ＴＲＨ和ＬＨＲＨ－Ａ能促进ＧＨ的分泌,Ｌ－ＤＯＰＡ、ＭＴ、ＧＡＢＡ对血清ＧＨ水平没有明显影响;Ｔ３则对ＧＨ分泌有一定的抑制作用。这说明鲤鱼ＧｔＨ和ＧＨ的分泌除了受各自的下丘脑释放因子和释放抑制因子的双重神经内分泌调控外,还受多种其它相同和不同调节因子的影响,也反映了鲤鱼ＧｔＨ和ＧＨ分泌的神经内分泌调控的复杂性。     

Chromosome analysis on 930 consecutive newborn children using quinacrine fluorescent banding technique

Summary Chromosome analysing using quinacrine fluorescence was performed on 930 consecutive newborn infants. The total incidence of major chromosome aberrations including numerical changes of the sex chromosomes, and structural changes of autosomes, was 0.54%. Incidences of XYY (0.4%) and XXY (0.2%) were relatively higher as compared to other studies. About 0.75% of the newborn infants were found to have a variable bright fluorescent band located on the proximal area of the short arm (p11) rather than on the proximal long arm (q11) of chromosome No. 3. Attempts were also made to record the variable fluorescent regions on 7 autosomes and the Y chromosome.     

Ability of Pollen to Germinate prior to Anthesis and Effect of Desiccation on Germination

The ability of pollen to germinate prior to anthesis was tested using Easter lily (Lilium longiflorum L.) and corn (Zea mays L.). Lily pollen normally dries to a low moisture content between anthesis and pollination while corn does not. The corn pollen germinated well (about 73%) when removed from anthers 1 day before anthesis and placed on culture medium. The lily pollen germinated poorly (0 to 5%) when harvested one to six days before anthesis. However, the lily pollen harvested one or two days before anthesis gave greatly improved germination (about 55%) after it was dried to a low moisture content. The results indicate that an internal control prevents premature germination of lily pollen and that drying is the final stage of pollen maturation. A different sort of regulatory mechanism must operate to prevent premature germination of corn pollen.     

Virulence and community dynamics of fungal species with vertical and horizontal transmission on a plant with multiple infections

The virulence evolution of multiple infections of parasites from the same species has been modeled widely in evolution theory. However, experimental studies on this topic remain scarce, particularly regarding multiple infections by different parasite species. Here, we characterized the virulence and community dynamics of fungal pathogens on the invasive plant Ageratina adenophora to verify the predictions made by the model. We observed that A. adenophora was highly susceptible to diverse foliar pathogens with mixed vertical and horizontal transmission within leaf spots. The transmission mode mainly determined the pathogen community structure at the leaf spot level. Over time, the pathogen community within a leaf spot showed decreased Shannon diversity; moreover, the vertically transmitted pathogens exhibited decreased virulence to the host A. adenophora, but the horizontally transmitted pathogens exhibited increased virulence to the host. Our results demonstrate that the predictions of classical models for the virulence evolution of multiple infections are still valid in a complex realistic environment and highlight the impact of transmission mode on disease epidemics of foliar fungal pathogens. We also propose that seedborne fungi play an important role in structuring the foliar pathogen community from multiple infections within a leaf spot.     

E35 ablates acute leukemia stem and progenitor cells in vitro and in vivo

Leukemia stem cells (LSCs) have critical functions in acute leukemia (AL) pathogenesis, participating in its initiation and relapse. Thus, identifying new molecules to eradicate LSCs represents a high priority for AL management. This work identified E35, a novel Emodin derivative, which strongly inhibited growth and enhanced apoptosis of AL stem cell lines, and primary stem and progenitor cells from AL cases, while sparing normal hematopoietic cells. Furthermore, functional assays in cultured cells and animals suggested that E35 preferentially ablated primitive leukemia cell populations without impairing their normal counterparts. Moreover, molecular studies showed that E35 remarkably downregulated drug-resistant gene and dramatically inhibited the Akt/mammalian target of rapamycin signaling pathway. Notably, the in vivo anti-LSC activity of E35 was further confirmed in murine xenotransplantation models. Collectively, these findings indicate E35 constitutes a novel therapeutic candidate for AL, potentially targeting leukemia stem and progenitor cells.     

Predictive value of protease-activated receptor-2 (PAR2) in cervical cancer metastasis

Metastasis is the primary cause of an unfavourable prognosis in patients with malignant cancer. Over the last decade, the role of proteinases in the tumour microenvironment has attracted increasing attention. As a sensor of proteinases, proteinase-activated receptor 2 (PAR₂) plays crucial roles in the metastatic progression of cervical cancer. In the present study, the expression of PAR₂ in multiple types of cancer was analysed by Gene Expression Profiling Interactive Analysis (GEPIA). Kaplan-Meier plotter was used to calculate the correlation between survival and the levels of PAR₂, Grb-associated binding protein 2(Gab2) and miR-125b. Immunohistochemistry (IHC) was performed to examine PAR₂ expression in a tissue microarray (TMA) of CESCs. Empower Stats was used to assess the predictive value of PAR₂ in the metastatic potential of CESC. We found that PAR₂ up-regulation was observed in multiple types of cancer. Moreover, PAR₂ expression was positively correlated with the clinicopathologic characteristics of CESC. miR-125b and its target Gab2, which are strongly associated with PAR₂-induced cell migration, are well-characterized as predictors of the prognostic value of CESC. Most importantly, the Cancer Genome Atlas (TCGA) data set analysis showed that the area under the curve (AUC) of the PAR₂ model was significantly greater than that of the traditional model (0.833 vs 0.790, P < .05), demonstrating the predictive value of PAR₂ in CESC metastasis. Our results suggest that PAR₂ may serve as a prognostic factor for metastasis in CESC patients.     

Cardiolipin interacts with beta‐2‐glycoprotein I and forms an open conformation–Mechanisms analyzed using hydrogen/deuterium exchange

Beta‐2‐glycoprotein I (β₂GPI) is the major antigen for the antiphospholipid antibodies in the antiphospholipid syndrome. The exposed epitope in domain I of β₂GPI can be recognized by the anti‐β₂GPI antibody. Here, we prepared the anionic di‐oleoyl‐phosphatidylserine (DOPS) and cardiolipin (CL) liposomes to interact with the β₂GPI. The conformational changes of β₂GPI upon binding with the liposomes were analyzed using hydrogen/deuterium exchange mass spectrometry. The exchange level of sequences 21–27 significantly increased after β₂GPI had interacted with DOPS. This change indicated a reduced interaction between domain I and domain V, inferring to a protrusion of the sequences 21–27 from the ring conformation. After β₂GPI had interacted with CL for 30 min, the exchange levels in 4 of the 5 domains increased significantly. The deuteration levels of sequences 1–20, 21–27, 196–205, 273–279 and 297–306 increased, suggesting that these regions had become more exposed, and the domain I was no longer in contact with domain V. The increasing deuteration levels in sequences 70–86, 153–162, 191–198, 196–205 and 273–279 indicated β₂GPI undergoing conformational changes to expose these inner regions, suggesting a structural transition. Overall, DOPS and CL induced minor conformational changes of β₂GPI at sequences 21–27 and forms an intermediate conformation after 10 min of interaction. After a complete protein–lipid interaction, high negatively charged CL membrane induced a major conformation transition of β₂GPI.     

Liquid–liquid phase separation of Tau by self and complex coacervation

The liquid–liquid phase separation (LLPS) of Tau has been postulated to play a role in modulating the aggregation property of Tau, a process known to be critically associated with the pathology of a broad range of neurodegenerative diseases including Alzheimer''s Disease. Tau can undergo LLPS by homotypic interaction through self‐coacervation (SC) or by heterotypic association through complex‐coacervation (CC) between Tau and binding partners such as RNA. What is unclear is in what way the formation mechanisms for self and complex coacervation of Tau are similar or different, and the addition of a binding partner to Tau alters the properties of LLPS and Tau. A combination of in vitro experimental and computational study reveals that the primary driving force for both Tau CC and SC is electrostatic interactions between Tau‐RNA or Tau‐Tau macromolecules. The liquid condensates formed by the complex coacervation of Tau and RNA have distinctly higher micro‐viscosity and greater thermal stability than that formed by the SC of Tau. Our study shows that subtle changes in solution conditions, including molecular crowding and the presence of binding partners, can lead to the formation of different types of Tau condensates with distinct micro‐viscosity that can coexist as persistent and immiscible entities in solution. We speculate that the formation, rheological properties and stability of Tau droplets can be readily tuned by cellular factors, and that liquid condensation of Tau can alter the conformational equilibrium of Tau.