Structural insight into chitin perception by chitin elicitor receptor kinase 1 of Oryza sativa

Plants have developed innate immune systems to fight against pathogenic fungi by monitoring pathogenic signals known as pathogen-associated molecular patterns (PAMP) and have established endo symbiosis with arbuscular mycorrhizal (AM) fungi through recognition of mycorrhizal (Myc) factors. Chitin elicitor receptor kinase 1 of Oryza sativa subsp. Japonica (OsCERK1) plays a bifunctional role in mediating both chitin-triggered immunity and symbiotic relationships with AM fungi. However, it remains unclear whether OsCERK1 can directly recognize chitin molecules. In this study, we show that OsCERK1 binds to the chitin hexamer ((NAG)₆) and tetramer ((NAG)₄) directly and determine the crystal structure of the OsCERK1-(NAG)₆ complex at 2 Å. The structure shows that one OsCERK1 is associated with one (NAG)₆. Upon recognition, chitin hexamer binds OsCERK1 by interacting with the shallow groove on the surface of LysM2. These structural findings, complemented by mutational analyses, demonstrate that LysM2 is crucial for recognition of both (NAG)₆ and (NAG)₄. Altogether, these findings provide structural insights into the ability of OsCERK1 in chitin perception, which will lead to a better understanding of the role of OsCERK1 in mediating both immunity and symbiosis in rice.     

Hedgehog-mediated paracrine interaction between hepatic stellate cells and marrow-derived mesenchymal stem cells

During liver injury, bone marrow-derived mesenchymal stem cells (MSCs) can migrate and differentiate into hepatocytes. Hepatic stellate cell (SC) activation is a pivotal event in the development of liver fibrosis. Therefore, we hypothesized that SCs may play an important role in regulating MSC proliferation and differentiation through the paracrine signaling pathway. We demonstrate that MSCs and SCs both express hedgehog (Hh) pathway components, including its ligands, receptors, and target genes. Transwell co-cultures of SCs and MSCs showed that the SCs produced sonic hedgehog (Shh), which enhanced the proliferation and differentiation of MSCs. These findings demonstrate that SCs indirectly modulate the activity of MSCs in vitro via the Hh pathway, and provide a plausible explanation for the mechanisms of transplanted MSCs in the treatment of liver fibrosis.     

An Excitatory Neural Assembly Encodes Short-Term Memory in the Prefrontal Cortex

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赫哲族掌指纹特征研究

本文对166名健康赫哲族人的掌指纹进行了研究,其中男性86名,女性80名。本文列出了58个赫哲族掌指纹参数,将其中52个掌指纹特征输入电子计算机,进行了相关及主成份分析。并且,将赫哲族的掌指纹特征与汉族的掌指纹特征进行了比较。 结果表明:赫哲族的掌指纹特征是与汉族相似的,并且有自己的特征;双手同名指的相关系数大于非同名指,单手相邻指的相关系数大于相隔指;在有关掌指纹特征的研究中,指纹的重要性大于掌纹。     

中国汉族男性臼齿磨耗与年龄关系的研究

本文对来自全国九个省区(江西、青海、吉林、河北、安徽、贵州、云南、广西、山东)的262个汉族男性颅骨上的992颗臼齿磨耗,进行了分析研究。探讨了牙齿磨耗的地区差异,提出了臼齿磨耗的新的分级方法。求出了M_1M_2在不同数目组合情况下,推算尸骨年龄的多个回归方程。     

Activated hepatic stellate cells promote angiogenesis in hepatocellular carcinoma by secreting angiopoietin-1

Angiogenesis is the central pathological process in hepatocellular carcinoma (HCC), and its progression is affected by tumor cells and the microenvironment. Activated hepatic stellate cells (aHSCs) are the most significant stromal cells involved in HCC. This study was aimed to explore the effects and mechanisms of aHSCs on angiogenesis in HCC. We isolated primary hepatoma cells, aHSCs, and hepatic vascular endothelial cells from human HCC samples. Then, we performed a novel in vitro assay and in vivo experiment in a nude mouse HCC model to investigate the functions of aHSCs on angiogenesis in HCC. Our results demonstrated that aHSCs are the primary sources of angiopoietin-1 (Ang-1) in human HCC in vitro, and aHSCs could promote hepatic vascular endothelial cell (HVEC) growth by secreting Ang-1. Furthermore, aHSCs could induce HVEC microtubule formation, and this ability was reduced when Ang-1 expression was silenced in aHSCs. In addition, CD34 expression in a nude mouse HCC model was downregulated when Ang-1 messenger RNA was silenced in aHSCs. Our data also indicated that HSC Ang-1 expression could be inhibited by overexpressing Raf kinase inhibitor protein. Therefore, we suggest that aHSCs promote angiogenesis through secreting Ang-1, potentially providing an interesting target for antiangiogenic therapies for HCC.     

胸骨的年龄变化

本文对120名已知生前准确年龄的中国汉族成年男性胸骨做了研究。样本来自全国九个省区,年龄范围19—74岁。研究结果发现,胸骨的柄体关节面、胸肋关节面和胸骨体背面骨质,随年龄的增加,明显地呈规律性变化。统计分析的结果表明,胸骨判定年龄的方法,效果较好,可以用于法医学和人类学实践。     

用中国汉族男性髓骨推断身高的研究

本文研究了以中国汉族男性航骨推断身高的方法．研究样本来自公安部第二研究所法医室近年收集的２４８对已知确切身高的汉族成年男性完整干燥防骨．依据人体测量学方法,共测量了１２项指标．相关分析表明,所测指标与身高的相关系数的统计学检验均有非常显著的意义．进而建立了航骨推断身高的直线回归方程及多元回归方程．并用３０对国人脱骨对各方程进行了盲测．结果表明,助骨推算身高的直线回归方程与多元日归方程所得结果与实际身高相近．效果较好．并且田骨推算身高的一元回归方程与多元回归方程的实用价值基本相同．     

中国汉族男性不同年龄阶段面貌特征的编码

推断年龄一直是法医人类学重点研究的内容。目前,最主要的年龄推断方法就是骨龄鉴定,但是成本较高。本文开拓新思路,利用照片推断年龄范围。将面部结构分成上中下三个区域,按区域进行观察和测量。实验选取12项指标,包括8项测量指标和4项观察指标。面部上1/3选取外眼角间距、内眼角间距、额纹和眉弓突出度;面部中间1/3选择容貌上面高、颧间距、鼻宽和鼻翼沟可见度;面部下1/3选择下颌长度、下颌角间距、口裂长度和口周皱褶。每项指标根据程度不同按数量级划分,统计出面部不同区域数字编码组合出现的频率。在面部上1/3处,20岁-组到60岁-组出现频率最高的组合分别为2311、3311、2311、1321和1333;在面中部1/3处,20岁-组到60岁-组出现频率最高的组合分别是1111、2311、2111、1212和3232;在面部下1/3处,20岁-组到60岁-组出现频率最高的组合分别是1111、1111、2211、2331和3332。