Phosphorylation of bovine neurofilament proteins by protein kinase FA (glycogen synthase kinase 3).

A highly purified preparation of protein kinase FA (where FA is the activating factor for phosphatase 1)/glycogen synthase kinase 3 from rabbit muscle readily phosphorylated bovine neurofilaments. All three neurofilament proteins, the high, middle, and low molecular proteins (NF-H, NF-M, and NF-L), were phosphorylated when intact filaments were incubated with the kinase. Experiments with individual proteins showed that NF-M was the best substrate. At protein concentrations of 0.13 mg/ml, the initial rate of NF-M phosphorylation was 30% of that observed for glycogen synthase. Km values were 0.24 mg/ml (7 x 10(-7) M tetramer) for glycogen synthase and 0.10 mg/ml (5 x 10(-7) M dimer) for NF-M. Vmax values were 0.36 mumol/min/mg for glycogen synthase and 0.035 mumol/min/mg for NF-M. Dephosphorylated NF-M was phosphorylated only half as much as native NF-M; this is consistent with the known substrate specificity of the kinase. The possible involvement of FA/GSK-3 in the phosphorylation of neurofilaments in vivo is discussed.     

A phosphoethanolamine-modified glycosyl diradylglycerol in the polar lipids of Clostridium tetani

The polar lipids of the anaerobic bacterium Clostridium tetani, the causative agent of tetanus, have been examined by two-dimensional thin layer chromatography, ESI mass spectrometry, and NMR spectroscopy. Plasmalogen and di- and tetra-acylated species of phosphatidylethanolamine, phosphatidylglycerol, cardiolipin, and N-acetylglucosaminyl diradylglycerol were the major lipids present in most strains examined except for strain ATCC 10779, the parent of strain E88, the first C. tetani strain to have its genome sequenced. This strain contained the same di- and tetra-acylated species but did not contain plasmalogens. All strains contained a novel derivative of N-acetylglucosaminyl diradylglycerol in which a phosphoethanolamine unit is attached to the 6’-position of the sugar, as judged by selective ³¹P-decoupled, ¹H-detected NMR difference spectroscopy. The N-acetylglucosamine (GlcNAc) residue is presumably linked to the 3-positon of the diradylglycerol moiety, and it has the β-anomeric configuration. Very little plasmalogen component was detected by mass spectrometry in the precursors phosphatidic acid and phosphatidylserine, consistent with the idea that plasmalogens are formed from diacylated phospholipids at a late stage of phospholipid assembly in anaerobic clostridia.     

Lymphoid cells recognize an alternatively spliced segment of fibronectin via the integrin receptor alpha 4 beta 1

Using purified recombinant fibronectins we show that WEHI 231 lymphoid cells spread only on fibronectin containing the alternatively spliced V region. Spreading is specifically blocked by peptides from the V25 segment (also called CS-1), which can be selectively spliced out independently of the rest of the V region. Using synthetic peptides we localize the binding site to a 10 amino acid segment that is highly conserved. Integrin alpha 4 beta 1 is a major integrin on the surfaces of these cells and binds specifically to the V25 segment with a primary specificity for the conserved 10 amino acid sequence. Antibodies to integrin alpha 4 inhibit spreading of WEHI 231 cells on V+ fibronectin. Therefore, integrin alpha 4 beta 1 is a fibronectin receptor specific for an alternatively spliced cell adhesion site and may play important roles in selective adhesion of various cell types to specific forms of fibronectin.     

Formation Mechanism and Occurrence Law of Pod Shattering in Soybean: A Review

Seed shattering refers to the phenomenon in which the pods split along the abdominal and back sutures before the crop is received, so that the seeds are spread. Seed shattering is vital to the reproduction of their offspring in wild plants, but it is also the main cause of crop yield loss reason. Pod-explosion resistance is a complex process of physical and physiological and biochemical reactions. Soybean seed shattering phenomenon is widespread, which severely restricts the development of soybean industry. Seed shattering (pod cracking or fruit dropping) is essential for the reproduction of its offspring in wild plants, but it is also the main cause of crop yield loss. This article analyzes the morphology and structure of pods related to seed shattering from the morphology of pods. On the basis of the regularity of the occurrence of seed shattering and the summary of phenotypic index identification methods, physiologically introduced the regulation mechanism of key enzymes and endogenous hormones on seed shattering. The localization, labeling and cloning of seed shattering genes are introduced in molecular biology. The study focused on reviewing the latest advances in the research on soybean seed shattering characteristics, and discussed with the research results of related crops. Finally, the research and application of soybean seed shattering resistance were prospected for several aspects.     

Phylogenomic conflict analyses in the apple genus Malus s.l. reveal widespread hybridization and allopolyploidy driving diversification,with insights into the complex biogeographic history in the Northern Hemisphere

Phylogenomic evidence from an increasing number of studies has demonstrated that different data sets and analytical approaches often reconstruct strongly supported but conflicting relationships. In this study, 785 single-copy nuclear genes and 75 complete plastomes were used to infer the phylogenetic relationships and estimate the historical biogeography of the apple genus Malus sensu lato, an economically important lineage disjunctly distributed in the Northern Hemisphere and involved in known and suspected hybridization and allopolyploidy events. The nuclear phylogeny recovered the monophyly of Malus s.l. (including Docynia); however, the genus was supported to be biphyletic in the plastid phylogeny. An ancient chloroplast capture event in the Eocene in western North America best explains the cytonuclear discordance. Our conflict analysis demonstrated that ILS, hybridization, and allopolyploidy could explain the widespread nuclear gene tree discordance. One deep hybridization event (Malus doumeri) and one recent event (Malus coronaria) were detected in Malus s.l. Furthermore, our historical biogeographic analysis integrating living and fossil data supported a widespread East Asian-western North American origin of Malus s.l. in the Eocene, followed by several extinction and dispersal events in the Northern Hemisphere. We also propose a general workflow for assessing phylogenomic discordance and biogeographic analysis using deep genome skimming data sets.     

Roles of ursodeoxycholic acid in the bile biochemistry and metabolomics in patients with choledocholithiasis: a prospective study

Metabolomics - A large number of studies have explored the potential biomarkers for detecting liver cirrhosis in an early stage, yet consistent conclusions are still warranted. To conduct a review...     

基于地形的牲畜空间利用特征及干扰评价——以王朗国家级自然保护区为例

地形是栖息地的基本要素, 从地形评价动物的空间利用特征能够掌握动物的分布规律并进行预测。为掌握保护区内牲畜的空间利用特征, 并评价它们对主要保护动物的潜在影响, 我们于2018年5-11月调查了王朗国家级自然保护区内牛和马的分布, 并结合红外相机监测结果及历史监测数据进行了分析和评价。结果表明: (1)虽然两种牲畜均偏好低海拔、低坡度、光照良好(半阳坡、阳坡)、距水源近的栖息地, 但它们在地形利用上存在显著差异; (2)牲畜活动最频繁的三条沟分别是竹根岔右一支沟、竹根岔正沟和大窝凼洋洞沟, 且呈现不同的干扰特征; (3)基于监测数据, 羚牛(Budorcas taxicolor tibetana)可能是保护区内最易受牛马活动威胁的保护动物。红外相机监测结果显示, 羚牛沿海拔分布现状可能是回避牲畜密集区域的结果。基于本研究, 我们建议: (1)保护区重点关注竹根岔(右一支沟、正沟、白沙沟)、大窝凼(洋洞沟、外侧坡)两个核心区的牲畜活动情况, 并尽快针对放牧采取措施。例如, 持续监测重点干扰区域牲畜的种群数量和空间分布趋势。(2)严格限制牲畜继续向高海拔栖息地入侵。(3)管控放牧投盐等干扰的发生频率。(4)加强执法力度, 防止牲畜对保护区带来的干扰持续和扩大, 威胁物种安全。