Ammonium affects cell viability to inhibit root growth in Arabidopsis

Ammonium (NH₄ ⁺) is an important form of nitrogen nutrient for most plants, yet is also a stressor for many of them. However, the primary events of NH₄ ⁺ toxicity at the cellular level are still unclear. Here, we showed that NH₄ ⁺ toxicity can induce the root cell death in a temporal pattern which primarily occurs in the cells of root maturation and elongation zones, and then spreads to the cells in the meristem and root cap. The results from the NH₄ ⁺-hypersensitive mutant hsn1 further confirmed our findings. Taken together, NH₄ ⁺ toxicity inhibits primary root growth by inhibiting cell elongation and division and inducing root cell death.     

拳卷地钱总黄酮提取物抗乙型肝炎病毒体外实验研究

目的:通过体外实验,探讨拳卷地钱总黄酮提取物抗乙肝病毒的作用。方法:将拳卷地钱总黄酮提取物作用于HBV-DNA转染细胞系2.2.15细胞,通过检测细胞培养液中HBsAg、HBeAg的变化来评价拳卷地钱总黄酮提取物抗乙肝病毒的效果及其可能的药理活性部位。结果:当拳卷地钱总黄酮提取物的最大无毒浓度为31.3μg·mL-1,对2.2.15细胞HBeAg、HBsAg分泌抑制率分别为51.56%、39.69%;治疗指数(TI)>2。结论:在2.2.15细胞无毒浓度下,拳卷地钱总黄酮对2.2.15细胞HBsAg、HBeAg分泌具有比较好的抑制作用;且可以有效阻止HBV-DNA表达和复制。提示:拳卷地钱总黄酮提取物在体外有一定的抗乙肝病毒作用。     

Construction of a eukaryotic expression vector pEGFP-C1-BMP-2 and its effect on cell migration

Objective  

Bone morphogenetic proteins (BMPs) are known to play an important role in bone and cartilage development. Recent research has shown that BMPs may induce tumorigenesis and promote tumor to spread, but the molecular mechanisms have not been elucidated. The aim of the present study was to investigate the regulatory function of BMP-2 in the migration of COS-7 cells and the underlying mechanisms.     

细胞生物学双语教学面临的问题及解决方法

文章详细论述了细胞生物学双语教学的意义、面临的问题及解决的对策,实施双语教学的具体方法、思路,重点讲述了课堂的教学组织以及课余的准备工作,为开展细胞生物学双语教学提供了理论基础.     

Review:Acute lung injury/acute respiratory distress syndrome (ALI/ARDS): the mechanism,present strategies and future perspectives of therapies

INTRODUCTION OF ACUTE LUNG IN- JURY/ACUTE RESPIRATORY DISTRESS SYN- DROME (ALI/ARDS) Acute lung injury (ALI) and its more severe form, the acute respiratory distress syndrome (ARDS) are syndromes of acute respiratory failure, which was defined by radiological (bilateral lung field infiltrates) and physiological (the ratio of arterial oxygen pres- sure and the inspiratory oxygen concentration, Pa O 2 /Fi O2≤300 mmHg for ALI and ≤200 mmHg for ARDS) criteria in…     

"物种混合"引起的伦理困境及其解决思路

用于治疗各种严重威胁人类疾病的基因移植和干细胞技术已经使制造越来越多的人兽混合体变得更容易和更迫切,当代社会出现了许许多多人兽混合的"喀迈拉"."喀迈拉"对人类伦理的挑战主要表现在:人体干细胞的来源、这些人兽混合体的生物学地位、社会地位和繁育后代等问题上都与人类的道德认同存在巨大反差.在对待"物种混合"引起的道德禁忌问题上,人类的态度应该更宽容一些.     

Structural changes of oviduct of freshwater shrimp, Macrobrachium nipponense （Decapoda, Palaemonidae）, during spawning

The structural change of the oviduct of freshwater shrimp （Macrobrachium nipponense） during spawning was examined by electron microscopy. The oviduct wall structural characteristics seem to be influenced significantly by the spawning process. Before the parturition and ovulation, two types of epithelial cells （types Ⅰ and Ⅱ） are found in the epithelium. The free surfaces of type Ⅰ and type Ⅱ cells have very dense long microvilli. Under the type Ⅰ and type Ⅱ cells, are a relatively thick layer of secreting material and a layer of mostly dead cells. After ovulation, two other types of epithelial cells （types Ⅲ and Ⅳ） are found in the oviduct wall epithelium. The free surface of type Ⅲ cells only has short microvilli scattered on the surface. The thick layer with secreting material and the dead cell layer disappeared at this stage. In some type Ⅲ cells, the leaking out of cytoplasm from broken cell membrane led to the death of these type Ⅲ cells. The transformation of all four types of epithelial cells was in the order： Ⅳ→Ⅰ→Ⅱ→Ⅲ.