石片研究

石片是石制品的重要组成部分, 其分类须遵循逻辑划分, 研究应规范化、系统化和简单化。按照台面和背面特征划分石片类型越来越趋向共识。石片台面由其背面缘和破裂面缘构成,是由直线、折线和弧线相互组成的几何图形, 它的形状反映剥片思维的逻辑构想。依据单疤、双疤、多疤组合和单向、双向、多向组合观察石片背面有助于剥片流程的分析。从背面观测石片的长度和划分左右较为合理, 参照人的手掌和手指判定石片大小和依据黄金分割律确认石片的形态应该是较有理的选择。石片除了制作食物外, 更多功效的猜想也值得考虑, 如敬奉首领、示爱异性、切割头发胡须、挠痒痒和清理排泄物等。     

Development and characterization of 33 polymorphic microsatellite markers in Trachurus japonicus by SLAF-seq technology

Trachurus japonicus is an economically important fish in the northwestern Pacific Ocean. However, its resources have declined seriously and there is an urgent need for a wide-range of investigations of the existing genetic resources. This requires a large number of diverse molecular markers with high discriminating power. In this study, we identified 43,264 perfect SSRs in T. japonicus genome using SLAF-seq technology. Of these, we randomly selected 106 SSRs (tri-nucleotide to hexa-nucleotide) to test for polymorphism. Eventually, we successfully developed a total of 33 loci including 8 tri-nucleotide and 25 long repeat motifs (tetra-nucleotide to hexa-nucleotide). The number of alleles (Na) of these loci ranged from 4 to 24 (mean 12.6). The observed heterozygosity (Ho) and expected heterozygosity (He) varied from 0.258 to 0.969 (mean 0.723) and from 0.452 to 0.962 (mean 0.827), respectively. All loci except TJ6-7 were highly informative (PIC > 0.5). These results showed that the shortlisted 33 loci exhibited moderate to relatively high genetic diversity, of which 18 were regarded as highly polymorphic and well-resolved. In summary, these diverse and potential microsatellites detected in our study provide substantial genetic basis for the screening of polymorphic SSR markers of T. japonicus and also provide a powerful tool to perform further studies on the genetic resource assessment and conservation of T. japonicus.     

Trefoil factor 2 secreted from damaged hepatocytes activates hepatic stellate cells to induce fibrogenesis

Liver fibrosis is a common characteristic of chronic liver diseases. The activation of hepatic stellate cells (HSCs) plays a key role in fibrogenesis in response to liver injury, yet the mechanism by which damaged hepatocytes modulate the activation of HSCs is poorly understood. Our previous studies have established that liver-specific deletion of O-GlcNAc transferase (OGT)leads to hepatocyte necroptosis and spontaneous fibrosis. Here, we report that OGT-deficient hepatocytes secrete trefoil factor 2 (TFF2) that activates HSCs and contributes to the fibrogenic process. The expression and secretion of TFF2 are induced in OGT-deficient hepatocytes but not in WT hepatocytes. TFF2 activates the platelet-derived growth factor receptor beta signaling pathway that promotes the proliferation and migration of primary HSCs. TFF2 protein expression is elevated in mice with carbon tetrachloride-induced liver injury. These findings identify TFF2 as a novel factor that mediates intercellular signaling between hepatocytes and HSCs and suggest a role of the hepatic OGT–TFF2 axis in the process of fibrogenesis.     

Enhanced production of a novel cytotoxic chromone oxalicumone A by marine-derived mutant Penicillium oxalicum SCSIO 24–2

Many marine natural products hold great potential for the development of new and much needed drugs. However, the production of active metabolites by marine-derived microorganisms is usually very low, and large-scale culture has to be involved to meet the need of chemical structural modification and deep pharmacy study. In order to enhance the production of a novel cytotoxic sulfur-containing chromone oxalicumone A (OA), germinating spores of a marine-derived wild strain Penicillium oxalicum SCSGAF 0023 were mutated by microwave and ultraviolet light irradiation, which led to the obtainment of a mutant P. oxalicum SCSIO 24–2 that could produce fivefold increase in OA production (3.42?±?0.21 mg/l) as compared to the wild strain. This is the first report that germinating spores are applied in marine-derived Penicillium sp. mutating to enhance the production of OA. Further, Plackett–Burman design and central composite design were adopted to optimize the basic medium components for increasing OA production by the mutant SCSIO 24–2 in shake flasks. The results indicated that three medium components including mannitol, maltose, and l-cysteine had significant effects on OA production, and their concentrations were optimized as 36, 27.9, and 0.99 g/l, respectively. In the optimized medium, the OA production (18.31?±?0.27 mg/l) by mutant SCSIO 24–2 was 4.4-fold higher than that in the basic medium. These results of this work promise to improve the present production of OA and may be adopted to enhance other objective products' production by marine-derived fungi.     

利用外源γ-氨基丁酸调控海洋绿藻亚心形四爿藻淀粉积累

微藻被看作第三代生物质能源的来源。微藻淀粉结构与高等植物的高度相似性使其可以作为粮食作物的替代,在生物能源领域有广泛的应用。γ-氨基丁酸(GABA)被认为是一种信号分子,可以调节植物细胞的生长代谢。本研究在缺氮培养条件下添加外源GABA调控海洋绿藻亚心形四爿藻生理代谢和淀粉积累。结果表明,添加外源GABA可以抑制细胞生长,降低光合作用效率;OJIP实验显示,GABA的添加增强了光合器官能量耗散,降低了光能利用效率,阻碍了电子传递,造成额外胁迫,从而促使细胞将碳流更多地分配到淀粉积累,导致藻细胞的淀粉含量、淀粉产量和淀粉产率提高。添加10 mmol/L GABA获得最大淀粉含量39%DW,比未添加GABA的对照组淀粉含量提高39%;同时获得最大淀粉产量和产率为1.72 g·L^-1和0.36 g·L^-1·d^-1,分别比未添加GABA的对照组提高39%和50%。以上结果表明在缺氮条件下添加外源GABA是一种调控亚心形四爿藻细胞代谢并提高其淀粉生产的有效方法。     

The complete mitochondrial genome of Solen strictus (Bivalvia: Solenidae)

In this paper, we determined the complete mitochondrial genome of Solen strictus (Bivalvia: Solenidae). The whole mitogenome of S. strictus is 16,535?bp in length with a base composition of 21.7% A, 41.0% T, 25.6% C, and 11.7% G and contains 12 protein-coding genes (atp8 is missing), 2 ribosomal RNA genes, 22 transfer RNA genes, and a major non-coding region (MNR). Some peculiar patterns including tandem repeats and microsatellite-like elements are found in the MNR of S. strictus.     

Crystal structure of cell adhesion molecule nectin-2/CD112 and its binding to immune receptor DNAM-1/CD226

The nectin and nectin-like molecule (Necl) family includes important cell adhesion molecules (CAMs) characterized by their Ig-like nature. Such CAMs regulate a broad spectrum of cell-cell interactions, including the interaction between NK cells and cytotoxic T lymphocytes (CTLs) and their target cells. CAM members nectin-2 (CD112) and Necl-5 (CD155) are believed to form homodimers (for nectin-2) or heterodimers in their functions for cell adhesion, as well as to interact with immune costimulatory receptor DNAX accessory molecule 1 (DNAM-1) (CD226) to regulate functions of both NK and CTL cells. However, the structural basis of the interactive mode of DNAM-1 with nectin-2 or Necl-5 is not yet understood. In this study, a soluble nectin-2 Ig-like V-set domain (nectin-2v) was successfully prepared and demonstrated to bind to both soluble ectodomain and cell surface-expressed full-length DNAM-1. The 1.85-? crystal structure of nectin-2v displays a perpendicular homodimer arrangement, revealing the homodimer characteristics of the nectin and Necls. Further mutational analysis indicated that disruption of the homodimeric interface of nectin-2v led to a failure of the homodimer formation, as confirmed by crystal structure and biochemical properties of the mutant protein of nectin-2v. Interestingly, the monomer mutant also loses DNAM-1 binding, as evidenced by cell staining with tetramers and surface plasmon resonance assays. The data indicate that interaction with DNAM-1 requires either the homodimerization or engagement of the homodimeric interface of nectin-2v. These results have implications for immune intervention of tumors or autoimmune diseases in the DNAM-1/nectin-2-dependent pathway.     

Alternaria-Induced Release of IL-18 from Damaged Airway Epithelial Cells: An NF-κB Dependent Mechanism of Th2 Differentiation?

Background

A series of epidemiologic studies have identified the fungus Alternaria as a major risk factor for asthma. The airway epithelium plays a critical role in the pathogenesis of allergic asthma. These reports suggest that activated airway epithelial cells can produce cytokines such as IL-25, TSLP and IL-33 that induce Th2 phenotype. However the epithelium-derived products that mediate the pro-asthma effects of Alternaria are not well characterized. We hypothesized that exposure of the airway epithelium to Alternaria releasing cytokines that can induce Th2 differentiation.

Methodology/Principal Finding

We used ELISA to measure human and mouse cytokines. Alternaria extract (ALT-E) induced rapid release of IL-18, but not IL-4, IL-9, IL-13, IL-25, IL-33, or TSLP from cultured normal human bronchial epithelial cells; and in the BAL fluids of naïve mice after challenge with ALT-E. Both microscopic and FACS indicated that this release was associated with necrosis of epithelial cells. ALT-E induced much greater IL-18 release compared to 19 major outdoor allergens. Culture of naïve CD4 cells with rmIL-18 induced Th2 differentiation in the absence of IL-4 and STAT6, and this effect was abrogated by disrupting NF- κB p50 or with a NEMO binding peptide inhibitor.

Conclusion/Significance

Rapid and specific release of IL-18 from Alternaria-exposed damaged airway epithelial cells can directly initiate Th2 differentiation of naïve CD4⁺ T-cells via a unique NF-κB dependent pathway.     

QTL-seq identifies an early flowering QTL located near Flowering Locus T in cucumber

Key message

Next-generation sequencing enabled a fast discovery of a major QTL controlling early flowering in cucumber, corresponding to the FT gene conditioning flowering time in Arabidopsis.

Abstract

Next-generation sequencing technologies are making it faster and more efficient to establish the association of agronomic traits with molecular markers or candidate genes, which is the requirement for marker-assisted selection in molecular breeding. Early flowering is an important agronomic trait in cucumber (Cucumis sativus L.), but the underlying genetic mechanism is unknown. In this study, we identified a candidate gene for early flowering QTL, Ef1.1 through QTL-seq. Segregation analysis in F₂ and BC₁ populations derived from a cross between two inbred lines “Muromskij” (early flowering) and “9930” (late flowering) suggested quantitative nature of flowering time in cucumber. Genome-wide comparison of SNP profiles between the early and late-flowering bulks constructed from F₂ plants identified a major QTL, designated Ef1.1 on cucumber chromosome 1 for early flowering in Muromskij, which was confirmed by microsatellite marker-based classical QTL mapping in the F₂ population. Joint QTL-seq and traditional QTL analysis delimited Ef1.1 to an 890 kb genomic region. A cucumber gene, Csa1G651710, was identified in this region, which is a homolog of the FLOWERING LOCUS T (FT), the main flowering switch gene in Arabidopsis. Quantitative RT-PCR study of the expression level of Csa1G651710 revealed significantly higher expression in early flowering genotypes. Data presented here provide support for Csa1G651710 as a possible candidate gene for early flowering in the cucumber line Muromskij.     

植物锌铁转运蛋白ZIP基因家族的研究进展

金属离子对植物的正常发育至关重要,但过量又会中毒.植物体内的自动调节平衡机制会调节金属离子的吸收和运输,从而控制金属离子的含量.锌铁调控蛋白ZIP( ZRT,IRT-like protein)家族是广泛存在于植物中的转运蛋白,具有Ca2+、Fe2+、Mn2+及Zn2+等多种金属元素的转运功能.了解ZIP转运体在植物中如何发挥离子转运功能,从分子水平认识金属离子缺乏或过量积累的机理有重要意义.综述拟南芥、水稻、大麦、苜蓿和玉米ZIP家族成员及其研究进展.