中国七星瓢虫群聚和迁飞的数学分析

自1976年首次在秦皇岛海岸发现七星瓤虫的群聚现象以来,又经过连续8年的广泛研究,进一步讨论了七星瓤虫在黄、渤海域的群聚范围、群聚数量、群聚规律以及迁飞等问题。本文的重点是试图从数学上论证七星瓤虫的迁飞,并进一步预测预报七星瓤虫的群聚日期,以便为群聚七星瓢虫的利用奠定基础。 根据可能有关的因子设64个自变量,2个因变量,通过反复计算,大量筛选可能与虫情有关的气象因子,结果入选的气象因子说明,群聚瓢虫是迁飞过程中迫降入海,并由风浪推上海岸的。经过用双层筛选逐步回归和逐步判别两种数学方法去筛选自变量,结果基本上是一致的。因此从定量角度对七星瓢虫的群聚和迁飞给出了论证。并说明七星瓢虫的群聚与近期气象条件密切相关,可以利用短期或中期气象预报代入判别式进行群聚的预测预报。     

人脑髓鞘碱性蛋白cDNA体外扩增、克隆和鉴定

采用聚合酶链反应(PCR)从人脑cDNA文库中扩增出600bp的髓鞘碱性蛋白(MBP)cDNA片段,与载体pGEM-3Zf(+)平端连接.重组质粒DNA转化宿主菌JM109,在含X-gal和IPTG的平板上直接筛选阳性克隆.限制性内切酶分析和成套引物扩增鉴定证明,该克隆含有7个外显子的21.5kD人脑MBP全长编码序列.     

真空负压和常规ABC法显示HPV—1抗原的应用比较

应用真空负压 ABC 法显示 HPV-1抗原比常规 ABC 法效果好,敏感性高,时间短,整个过程只需一个多小时,阳性物明显突出,颗粒均匀,色泽鲜艳,呈黄棕色,背景清晰等优点。还可提高抗体的稀释度,降低成本。与微波技术相比,具有设备简单,易于操作,安全可靠,不受条件限制,经对26例尖锐湿疣的病例进行多层次稀释度的研究,取得了满意的结果,认为该法值得推广应用。     

Osthole stimulates bone formation,drives vascularization and retards adipogenesis to alleviate alcohol‐induced osteonecrosis of the femoral head

Characteristic pathological changes in osteonecrosis of the femoral head (ONFH) include reduced osteogenic differentiation of bone mesenchymal stem cells (BMSCs), impaired osseous circulation and increased intramedullary adipocytes deposition. Osthole is a bioactive derivative from coumarin with a wide range of pharmacotherapeutic effects. The aim of this study was to unveil the potential protective role of osthole in alcohol‐induced ONFH. In vitro, ethanol (50 mmol/L) remarkably decreased the proliferation and osteogenic differentiation of BMSCs and impaired the proliferation and tube formation capacity of human umbilical vein endothelial cell (HUVECs), whereas it substantially promoted the adipogenic differentiation of BMSCs. However, osthole could reverse the effects of ethanol on osteogenesis via modulating Wnt/β‐catenin pathway, stimulate vasculogenesis and counteract adipogenesis. In vivo, the protective role of osthole was confirmed in the well‐constructed rat model of ethanol‐induced ONFH, demonstrated by a cascade of radiographical and pathological investigations including micro‐CT scanning, haematoxylin‐eosin staining, TdT‐mediated dUTP nick end labelling, immunohistochemical staining and fluorochrome labelling. Taken together, for the first time, osthole was demonstrated to rescue the ethanol‐induced ONFH via promoting bone formation, driving vascularization and retarding adipogenesis.     

Half‐Heusler Thermoelectric Module with High Conversion Efficiency and High Power Density

Half‐Heusler (HH) compounds have shown great potential in waste heat recovery. Among them, p‐type NbFeSb and n‐type ZrNiSn based alloys have exhibited the best thermoelectric (TE) performance. However, TE devices based on NbFeSb‐based HH compounds are rarely studied. In this work, bulk volumes of p‐type (Nb_0.8Ta_0.2)_0.8Ti_0.2FeSb and n‐type Hf_0.5Zr_0.5NiSn_0.98Sb_0.02 compounds are successfully prepared with good phase purity, compositional homogeneity, and matchable TE performance. The peak zTs are higher than 1.0 at 973 K for Hf_0.5Zr_0.5NiSn_0.98Sb_0.02 and at 1200 K for (Nb_0.8Ta_0.2)_0.8Ti_0.2FeSb. Based on an optimal design by a full‐parameters 3D finite element model, a single stage TE module with 8 n‐p HH couples is assembled. A high conversion efficiency of 8.3% and high power density of 2.11 W cm^?2 are obtained when hot and cold side temperatures are 997 and 342 K, respectively. Compared to the previous TE module assembled by the same materials, the conversion efficiency is enhanced by 33%, while the power density is almost the same. Given the excellent mechanical robustness and thermal stability, matchable thermal expansion coefficient and TE properties of NbFeSb and ZrNiSn based HH alloys, this work demonstrates their great promise for power generation with both high conversion efficiency and high power density.     

Enhanced regional terrestrial carbon uptake over Korea revealed by atmospheric CO2 measurements from 1999 to 2017

Understanding changes in terrestrial carbon balance is important to improve our knowledge of the regional carbon cycle and climate change. However, evaluating regional changes in the terrestrial carbon balance is challenging due to the lack of surface flux measurements. This study reveals that the terrestrial carbon uptake over the Republic of Korea has been enhanced from 1999 to 2017 by analyzing long‐term atmospheric CO₂ concentration measurements at the Anmyeondo Station (36.53°N, 126.32°E) located in the western coast. The influence of terrestrial carbon flux on atmospheric CO₂ concentrations (ΔCO₂) is estimated from the difference of CO₂ concentrations that were influenced by the land sector (through easterly winds) and the Yellow Sea sector (through westerly winds). We find a significant trend in ΔCO₂ of ?4.75 ppm per decade (p < .05) during the vegetation growing season (May through October), suggesting that the regional terrestrial carbon uptake has increased relative to the surrounding ocean areas. Combined analysis with satellite measured normalized difference vegetation index and gross primary production shows that the enhanced carbon uptake is associated with significant nationwide increases in vegetation and its production. Process‐based terrestrial model and inverse model simulations estimate that regional terrestrial carbon uptake increases by up to 18.9 and 8.0 Tg C for the study period, accounting for 13.4% and 5.7% of the average annual domestic carbon emissions, respectively. Atmospheric chemical transport model simulations indicate that the enhanced terrestrial carbon sink is the primary reason for the observed ΔCO₂ trend rather than anthropogenic emissions and atmospheric circulation changes. Our results highlight the fact that atmospheric CO₂ measurements could open up the possibility of detecting regional changes in the terrestrial carbon cycle even where anthropogenic emissions are not negligible.     

GPI7-mediated glycosylphosphatidylinositol anchoring regulates appressorial penetration and immune evasion during infection of Magnaporthe oryzae

Glycosylphosphatidylinositol (GPI) anchoring plays key roles in many biological processes by targeting proteins to the cell wall; however, its roles are largely unknown in plant pathogenic fungi. Here, we reveal the roles of the GPI anchoring in Magnaporthe oryzae during plant infection. The GPI-anchored proteins were found to highly accumulate in appressoria and invasive hyphae. Disruption of GPI7, a GPI anchor-pathway gene, led to a significant reduction in virulence. The Δgpi7 mutant showed significant defects in penetration and invasive growth. This mutant also displayed defects of the cell wall architecture, suggesting GPI7 is required for cell wall biogenesis. Removal of GPI-anchored proteins in the wild-type strain by hydrofluoric acid (HF) pyridine treatment exposed both the chitin and β-1,3-glucans to the host immune system. Exposure of the chitin and β-1,3-glucans was also observed in the Δgpi7 mutant, indicating GPI-anchored proteins are required for immune evasion. The GPI anchoring can regulate subcellular localization of the Gel proteins in the cell wall for appressorial penetration and abundance of which for invasive growth. Our results indicate the GPI anchoring facilitates the penetration of M. oryzae into host cells by affecting the cell wall integrity and the evasion of host immune recognition.     

The essential effector SCRE1 in Ustilaginoidea virens suppresses rice immunity via a small peptide region

The biotrophic fungal pathogen Ustilaginoidea virens causes rice false smut, a newly emerging plant disease that has become epidemic worldwide in recent years. The U. virens genome encodes many putative effector proteins that, based on the study of other pathosystems, could play an essential role in fungal virulence. However, few studies have been reported on virulence functions of individual U. virens effectors. Here, we report our identification and characterization of the secreted cysteine-rich protein SCRE1, which is an essential virulence effector in U. virens. When SCRE1 was heterologously expressed in Magnaporthe oryzae, the protein was secreted and translocated into plant cells during infection. SCRE1 suppresses the immunity-associated hypersensitive response in the nonhost plant Nicotiana benthamiana. Induced expression of SCRE1 in rice also inhibits pattern-triggered immunity and enhances disease susceptibility to rice bacterial and fungal pathogens. The immunosuppressive activity is localized to a small peptide region that contains an important ‘cysteine-proline-alanine-arginine-serine’ motif. Furthermore, the scre1 knockout mutant generated using the CRISPR/Cas9 system is attenuated in U. virens virulence to rice, which is greatly complemented by the full-length SCRE1 gene. Collectively, this study indicates that the effector SCRE1 is able to inhibit host immunity and is required for full virulence of U. virens.     

Two Phytophthora parasitica cysteine protease genes,PpCys44 and PpCys45, trigger cell death in various Nicotiana spp. and act as virulence factors

Proteases secreted by pathogens have been shown to be important virulence factors modifying plant immunity, and cysteine proteases have been demonstrated to participate in different pathosystems. However, the virulence functions of the cysteine proteases secreted by Phytophthora parasitica are poorly understood. Using a publicly available genome database, we identified 80 cysteine proteases in P. parasitica, 21 of which were shown to be secreted. Most of the secreted cysteine proteases are conserved among different P. parasitica strains and are induced during infection. The secreted cysteine protease proteins PpCys44/45 (proteases with identical protein sequences) and PpCys69 triggered cell death on the leaves of different Nicotiana spp. A truncated mutant of PpCys44/45 lacking a signal peptide failed to trigger cell death, suggesting that PpCys44/45 functions in the apoplastic space. Analysis of three catalytic site mutants showed that the enzyme activity of PpCys44/45 is required for its ability to trigger cell death. A virus-induced gene silencing assay showed that PpCys44/45 does not induce cell death on NPK1 (Nicotiana Protein Kinase 1)-silenced Nicotiana benthamiana plants, indicating that the cell death phenotype triggered by PpCys44/45 is dependent on NPK1. PpCys44- and PpCys45-deficient double mutants showed decreased virulence, suggesting that PpCys44 and PpCys45 positively promote pathogen virulence during infection. PpCys44 and PpCys45 are important virulence factors of P. parasitica and trigger NPK1-dependent cell death in various Nicotiana spp.