Induction of systemic stress tolerance by brassinosteroid in Cucumis sativus

? Brassinosteroids (BRs) are a new class of plant hormones that are essential for plant growth and development. Here, the involvement of BRs in plant systemic tolerance to biotic and abiotic stresses was studied. ? The effects of 24-epibrassinolide (EBR) on plant stress tolerance were studied through the assessment of symptoms of photooxidative stress by chlorophyll fluorescence imaging pulse amplitude modulation, the analysis of gene expression using quantitative real-time PCR and the measurement of hydrogen peroxide (H?O?) production using a spectrophotometric assay or confocal laser scanning microscopy. ? Treatment of primary leaves with EBR induced systemic tolerance to photooxidative stress in untreated upper and lower leaves. This was accompanied by the systemic accumulation of H?O? and the systemic induction of genes associated with stress responses. Foliar treatment of EBR also enhanced root resistance to Fusarium wilt pathogen. Pharmacological study showed that EBR-induced systemic tolerance was dependent on local and systemic H?O? accumulation. The expression of BR biosynthetic genes was repressed in EBR-treated leaves, but elevated significantly in untreated systemic leaves. Further analysis indicated that EBR-induced systemic induction of BR biosynthetic genes was mediated by systemically elevated H?O?. ? These results strongly argue that local EBR treatment can activate the continuous production of H?O?, and the autopropagative nature of the reactive oxygen species signal, in turn, mediates EBR-induced systemic tolerance.     

泽漆营养器官发育解剖学研究

采用石蜡切片法、半薄切片法对泽漆营养器官的发育过程进行了观察,同时对3种器官中乳汁管的分布和大小进行了分析。结果表明:泽漆根的发育类似于草本双子叶植物根的一般发育规律。初生木质部为三原型。茎的初生结构由表皮、皮层、维管束环和髓构成,其髓中有空腔,而茎的次生生长过程中维管形成层的活动短暂,仅产生少量次生维管组织,不形成周皮。叶的发育包括原分生组织、初生分生组织和成熟结构3个阶段,属于异面叶结构。泽漆乳汁管主要分布在维管束韧皮部的外侧。在3种器官中,乳汁管直径差异较大,依次为根>茎>叶。     

Site-specific transfer of an intact beta-globin gene cluster through a new targeting vector

The ideal gene-therapy vector for treating genetic disorders should deliver intact therapeutic genes and their essential regulatory elements into the specific "safe genomic site" and realize long-term, self-regulatory expression. For beta-thalassemia gene therapy, viral vectors have been broadly used, but the accompanying insertional mutation and immunogenicity remain problematic. Hence, we aimed to develop new non-viral vectors that are efficient and safe in treating diseases. As previous studies have demonstrated that physiological expression of beta-globin genes requires both a 5' locus control region and 3' specific elements, we constructed a new human chromosome-derived targeting vector to transfer the intact beta-globin gene cluster into K562 cells. The whole beta-globin gene cluster was precisely integrated into the target site and expressed in a self-regulatory pattern. The results proved that the human chromosome-derived vector was specifically targeted to the human genome and this could provide a novel platform for further gene therapy research.     

A novel rice C2H2-type zinc finger protein lacking DLN-box/EAR-motif plays a role in salt tolerance

A cDNA for the gene ZFP182, encoding a C2H2-type zinc finger protein, was cloned from rice by RT-PCR. ZFP182 codes an 18.2 kDa protein with two C2H2-type zinc finger motifs, one nuclear localization signal and one Leu-rich domain. The DLN-box/EAR-motif, which exists in most of plant C2H2-type zinc finger proteins, does not exist in ZFP182. The expression analysis showed that ZFP182 gene was constitutively expressed in leaves, culms, roots and spikes at the adult rice plants, and markedly induced in the seedlings by cold (4 degrees C), 150 mM NaCl and 0.1 mM ABA treatments. The approximate 1.4 kb promoter region of ZFP182 gene was fused into GUS reporter gene and transformed into tobacco. The histochemical analysis revealed that GUS expression could not be detected in transformed tobacco seedlings under normal conditions, but strongly observed in tobacco leaf discs and the vascular tissue of roots treated with NaCl or KCl. Expression of ZFP182 in transgenic tobacco and overexpression in rice increased plant tolerance to salt stress. These results demonstrated that ZFP182 might be involved in plant responses to salt stress.     

Transplantation of embryonic stem cell-derived cardiomyocytes improves cardiac function in infarcted rat hearts

BACKGROUND: Post-infarct congestive heart failure is one of the leading causes of morbidity and mortality in industrialized countries. The main purpose of this study was to investigate whether transplantation of embryonic stem cell-derived cardiomyocytes (ESCM) directly into the infarcted myocardium could improve cardiac function in rats. METHODS: Cell culture medium with or without ESCM was injected into the borders of cardiac scar tissue 1 week after experimental infarction. Cardiac performance was evaluated 4 weeks later by means of echocardiography after ESCM (n=16) or medium (n=12) injection. RESULTS: ESCM implantation significantly improved fractional shortening (31.5+/-3. 8%) compared with medium-treated hearts (21.3+/-5.2%; P<0.05) and preserved left ventricular structure. Co-localization of 4',6-diamidino-2-phenylindole-labeled nuclei of transplanted cells with cardiomyocyte markers for cardiac troponin T and connexin-43, as detected by immunofluorescent microscopy, indicated the regeneration of damaged myocardium and the formation of gap junctions between grafted and host cells. However, intra-myocardial teratomas were observed in the hearts of two of the 16 grafted animals, at the fourth week after ESCM transplantation. DISCUSSION: Our results suggest that, although ESCM implantation can improve the function of infarcted myocardium, strategies to prevent tumorigenesis should be developed.     

EGF receptor clustering is induced by a 0.4 mT power frequency magnetic field and blocked by the EGF receptor tyrosine kinase inhibitor PD153035

Atomic force microscopy (AFM), transmission electron microscopy (TEM), and confocal laser scanning microscopy were used to investigate the effects of a 50 Hz 0.4 mT magnetic field (MF) on the clustering of purified epidermal growth factor receptors (EGFRs) and EGFRs in Chinese hamster lung (CHL) cell membrane. The results demonstrate that exposing purified EGFRs to the MF for 30 min induces receptor clustering. The peak height of apparent clusters increased from 1.42 +/- 0.18 (sham-exposed) to 3.08 +/- 0.38 nm (exposed) while the mean half-width increased from 21.7 +/- 2.2 to 33.0 +/- 4.0 nm. A similar effect was also observed by TEM. Treatment of purified EGFR with PD153035 (PD), an EGFR-specific tyrosine kinase (TK) inhibitor, inhibited the MF-induced EGFR clustering of the purified proteins, an effect also observed for the receptors in cell membrane in the absence of EGF. These results strongly suggest that the 50 Hz 0.4 mT MF interferes with the EGFR signaling pathway, most likely by interacting with the cytoplasmic TK domain.     

Efficient plant regeneration of native spearmint (Mentha spicata L.)

Summary Protocols and media constituents for efficient in vitro plant regeneration of Native Spearmint (Mentha spicata L. cultivar ‘Native Spearmint’) have been defined. Adventitious shoots were initiated either directly from morphogenetically competent cells of explants or primary callus. Leaf explants from at least 2-mo.-old in vitro-maintained shoots exhibited the greatest morphogenetic capacity. Explants derived from basal portions of leaves at the bottom of the shoot were most responsive, with up to a 100% regeneration frequency and greater than nine shoots per explant. Highest frequency of meristemoids and morphogenetic callus were initiated from explants cultured onto a basal medium containing Murashige and Skoog (MS) salts, supplemented with 4 mg thidiazuron (TDZ) per L and 25% (vol/vol) coconut water (CW) for 10 to 14 d in darkness. Bud and shoot development required removal of both TDZ and CW from the medium. Shoot propagules were transferred to basal medium supplemented with 0.01 mg α-naphthaleneacetic acid (NAA) per L and grown under low light for about 2 wk to facilitate shoot elongation. Individual shoots about 1 cm tall were dissected and retransferred onto the same medium. Root initiation began within 4 to 6 d and a functional root system developed within 2 to 3 wk. These plantlets were transferred to soil and acclimated successfully for growth and development in a greenhouse. This is the first report of an efficient regeneration system for Native Spearmint based on adventitious organogenesis.     

黑龙江五大连池的生态价值分析

黑龙江五大连池处于大小兴安岭和松嫩平原的交错地带,在过去210万年间经历了7次大规模的火山喷发,是中国保存最为完好的内陆火山遗迹,2010年被我国政府遴选为世界自然遗产提名地.为了科学、准确地阐述五大连池生态方面的突出普遍价值,本文在<实施世界遗产公约操作指南>的框架下,整合野外调查数据和文献资料,在与其他相关世界遗产地充分比较的基础上,较为全面地分析了五大连池的生态价值.五大连池植物地理特征交错,区系来源广泛;物种组成相对丰富;发育在熔岩台地上的矮曲林反映了植物的特殊适应过程:特有成因形成了陆生和水生两个完整的植被演替序列;陆生植被演替同时存在普通演替和斑块动态演替两种模式,在熔岩地貌上斑块动态演替模式更为随机而高效.上述生态特征充分展示了五大连池正在进行的生物生态过程,体现了五大连池独特的生态价值,为后续有效保护和深入科学研究提供了支撑.     

千金子不同极性部位对酪氨酸酶活性的影响

测定千金子醇提物不同极性部位对酪氨酸酶活性的影响。以L-酪氨酸为底物,采用比色法测定千金子不同极性部位对酪氨酸酶的抑制率。得到了千金子醇提物的乙酸乙酯相、正丁醇相和水相的半数抑制率(IC50值)分别为0.150 mg/mL,0.813 mg/mL,7.570 mg/mL,并对乙酸乙酯相进一步分离得到七叶内酯,其IC50值0.103 mg/mL。结果表明千金子中起到酪氨酸酶抑制性的物质为七叶内酯,主要分布在乙酸乙酯相中。为千金子中酪氨酸酶抑制性物质的筛选提供科学依据。     

增殖细胞核抗原在低氧大鼠肺动脉平滑肌细胞中表达

目的通过建立低氧性肺动脉高压大鼠模型,探讨增殖细胞核抗原(proliferating cell nuclear antigen,PCNA)在大鼠低氧性肺血管平滑肌细胞中的表达。方法将SPF级SD大鼠随机分为正常对照组(n=10)、模型组(n=10),通过间断常压低氧法建立大鼠低氧性肺动脉高压模型,肺组织切片经HE染色后图像分析技术定量检测大鼠肺小动脉的形态改变;免疫组织化学染色法测定肺血管平滑肌细胞内PCNA蛋白表达,并经图像分析半定量检测其表达强度。结果 4周后,模型组SD大鼠MT%、MA%与对照组比较,差异具有显著性(P<0.05);模型组SD大鼠肺血管平滑肌细胞内PCNA核蛋白表达(积分面积、累积光密度)与对照组比较,差异具有显著性(P<0.05)。结论常压低氧4周可成功建立肺动脉高压大鼠模型,PCNA在肺血管平滑肌细胞中的表达量具有差异性提示其可能在肺动脉高压形成过程中起重要作用。