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201.
Distribution ecology of pollen tubes: fine-grained, labile spatial mosaics in southern Spanish Lamiaceae 总被引:1,自引:1,他引:0
Carlos M. Herrera 《The New phytologist》2004,161(2):473-484
202.
The formation of new capillaries from existing blood vessels is critical for tumor growth and metastasis. In this study we
report that amentoflavone, a biflavonoid from Biophytum sensitivum, could inhibit the process of angiogenesis. Amentoflavone at nontoxic concentrations (0.05–0.2 μg/ml) showed significant
inhibition in the proliferation, migration, and tube formation of endothelial cells, which are key events in the process of
angiogenesis. In vivo studies in C57BL/6 mice using amentoflavone showed remarkable inhibition (52.9%) of tumor directed capillary formation. Amentoflavone
showed inhibitory effect on the production of various endogenous factors such as IL-1β, IL-6, TNF-α, GM-CSF, and VEGF that
control the process of angiogenesis. Amentoflavone treatment could increase the production of IL-2 and TIMP-1, which could
successfully shift the equilibrium towards an angiostatic condition. The antiangiogenic activity of amentoflavone was supported
by its remarkable suppression in sprouting of microvessels from rat aorta. Our results also show that amentoflavone could
inhibit the production of VEGF mRNA in B16–F10 cells. These findings indicate that amentoflavone inhibits angiogenesis by
disrupting the integrity of endothelial cells and by altering the endogenous factors that are required for the process of
neovascularization.
Published in Russian in Biokhimiya, 2008, Vol. 73, No. 2, pp. 258–269. 相似文献
203.
中华芦荟组培苗与正常苗某些理化特性的比较研究 总被引:3,自引:0,他引:3
对中华芦荟(Aloe vera L.var.chinensis) 组培苗与正常苗的干重,含水量,可溶性糖含量,叶绿素及类胡萝卜素含量,蛋白质含量及蛋白质电泳,光合速率,呼吸速率,超氧化物歧化酶活性等理化指标进行了比较研究,结果表明,中华芦荟组培苗与正常苗的上述各项指标均差异不显著,证明植物组织培养方法是中华芦荟快繁的一条有效途径,可用组培苗来代替正常的扦插苗。 相似文献
204.
珍稀濒危植物蒙古扁桃的组织培养及植株再生 总被引:14,自引:2,他引:12
对珍稀濒危植物蒙古扁桃进行组织培养获得再生植株。实验结果表明,在MS培养基上蒙古扁桃幼苗茎尖,茎切段和叶片等外植体均可以脱分化形成愈伤组织,并进一步分化形成再生植株。器官的脱分化与再分化决定于培养基中的激素种类及其浓度。诱导愈伤组织形成的最适培养基为MS+6-BA0.8mg/L NAA0.1mg/L,芽分化诱导最适培养基为MS+6-BA0.8mg/L,诱导生根的最适培养基是MS+IBA0.5mg/L。 相似文献
205.
Little is known about physiological changes that occur with micropropagated chile ancho pepper (Capsicum annuum L. cv. San Luis) plantlets during acclimatization. Plantlets were transferred to ex vitro conditions to study selected physiological changes and growth performance during acclimatization and post-acclimatization.
The physiology of the plantlets was characterized by measuring leaf gas exchange and water status. Plant growth was determined
by assessing plant height, leaf number, total leaf area, relative growth rate (RGR), and leaf, root, and stem dry matter (DM).
Chile pepper plantlets became acclimatized within 6 days after transplantation. During this period, physiological adjustments
occurred, which were critical for plantlet survival. After initial ex vitro transplanting, plantlets experienced water deficit [leaf wilting and reduced relative water content (RWC)], which corresponded
with reduced stomatal conductance (g
s) and transpiration (E), and an increase in stomatal resistance (r
s). Thus, leaf stomata that developed in vitro were functional ex vitro. Because of this stomatal control, plantlets minimized transplant shock, recovered and survived. Prior to transplanting,
plantlets were photomixotrophic, as indicated by low photosynthetic rates (A). During acclimatization, RWC, g
s, E, and A were significantly lower two days after transplanting. However, within 6 days after transplanting, plantlets recovered and
became photoautotrophic – attaining high A, g
s, and E. Water use efficiency was initially low during the first days after transplanting, but increased dramatically at the end
of the acclimatization period in part due to increased A. The stabilization and improvement of plantlet water status and gas exchange during acclimatization and post-acclimatization
closely correlated with increased plantlet growth.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
206.
207.
V. Raghavan 《The New phytologist》2003,159(3):565-583
208.
神经管畸形相关基因的研究进展 总被引:7,自引:1,他引:6
神经管畸形是由遗传和环境因素共同作用而导致的一种常见的出生缺陷。遗传因素中包括细胞增殖因子、转录因子及影响叶酸代谢的关键酶的基因。本文着重从动物模型和群体流行病学调查两方面,简述目前研究的热点基因及特定位点的遗传多态性与神经管畸形的关系,从而揭示多因素作用在神经管畸形病因学研究中的意义。
Progress in Researches on Neural Tube Defects Related the Genes
QU Mei,LI Zhu
Institute of Reproductive and Child Health of Peking University,National Reference Laboratory on Reproductive Health Research Ministry of Health,Beijing 100083,China
Abstract:Neural tube defects are common birth defects which are ascribed to the combination of genetic and environmental factors.The genetic factors include cell growth factors,transformation factors and key enzymic genes involved in folate metabolism.This paper reviews the genes as focus of current investigantion and the relationship between the genetic polymorphism on the specific sites and neural tube defects based on animal model and population epidemiological study.It indicats that the multifactors play an important role in the etiology of neural tube defects.
Key words:neural tube defects; genetic polymorphism 相似文献
209.
Ella Tour Graciela Pillemer Yosef Gruenbaum Abraham Fainsod 《Mechanisms of development》2002,110(1-2):3-13
Development and differentiation of the vertebrate caudal midbrain and anterior hindbrain are dependent on the isthmic organizer signals at the midbrain/hindbrain boundary (MHB). The future MHB forms at the boundary between the Otx2 and Gbx2 expression domains. Recent studies in mice and chick suggested that the apposition of Otx2- and Gbx2-expressing cells is instrumental for the positioning and early induction of the MHB genetic cascade. We show that Otx2 and Gbx2 perform different roles in this process. We find that ectopically expressed Otx2 on its own can induce a substantial part of the MHB genetic network, namely En2, Wnt1, Pax-2, Fgf8 and Gbx2, in a concentration-dependent manner. This induction does not require protein synthesis and ends during neurulation. In contrast, Gbx2 is a negative regulator of Otx2 and the MHB genes. Based on the temporal patterns of expression of the genes involved, we propose that Otx2 might be the early inducer of the isthmic organizer genetic network while Gbx2 restricts Otx2 expression along the anterior-posterior axis and establishes an Otx2 gradient. 相似文献
210.
The structure of the neural complex has been studied under a light microscope in the representatives of 4 genera belonging to the family Polyclinidae. Particular attention was given to the relationships between the ciliary organ, dorsal tube, and neural gland. No dorsal string was found in Polyclinidae. The neural gland is located in the proximal portion of the mediodorsal blood vessel of the branchial sac. This paper discusses probable reasons for the differences in the structure of the neural complex in different ascidians taking into account original data and the existing literature. 相似文献