头花杜鹃、陇蜀杜鹃及杜鹃属植物叶绿体基因组比较分析

头花杜鹃(Rhododendron capitatum)和陇蜀杜鹃(R. przewalskii)是极具观赏价值的野生花卉和药用植物。为探讨头花杜鹃和陇蜀杜鹃叶绿体基因组的遗传结构及进化特征,该研究利用 Illumina HiSeq 4000 平台对头花杜鹃和陇蜀杜鹃的叶绿体全基因组进行测序,经组装和注释后,结合 7 个已发表的杜鹃属植物叶绿体全基因组进行比较基因组学分析和系统发育分析。结果表明:(1)头花杜鹃和陇蜀杜鹃叶绿体全基因组呈典型的环状四分体结构,均由一个大单拷贝区(105 990、109 191 bp)、一个小单拷贝区(2 617、2 606 bp)和一对反向重复区(45 825、47 516 bp)构成,全长分别为200 257、206 829 bp。(2)头花杜鹃和陇蜀杜鹃叶绿体基因组中共鉴定出 263 个SSR位点,大部分 SSR 偏好使用 A/T 碱基,密码子偏好使用 A/U 结尾。(3)杜鹃属植物叶绿体全基因组中普遍存在基因丢失以及基因组重排等结构变异现象。该研究丰富了杜鹃属植物的基因组资源,为头花杜鹃、陇蜀杜鹃的资源开发、遗传进化、育种及系统发育相关研究提供了理论参考。     

养殖刺参附着期“化板症”病原菌的分离鉴定及来源分析

摘要：【目的】查明养殖刺参附着期“化板症”的病原及其来源,并获得该病的治疗药物。【方法】分别对化板症状较为典型的3家育苗场的发病幼体进行病原学分析,对可疑病原进行人工回接感染并进行形态学、生理生化和16S rDNA序列分析鉴定,对各养殖场育苗系统,包括水源、养殖池水、池底污物、附着基板和饵料进行细菌学分析,对病原菌进行药敏测试。【结果】从所有病参中分离得到1种优势菌株,人工回接感染证明它对健康刺参有较强的致病性,且感染病参与自然发病刺参的症状相同。鉴定出“化板症”的病原为弧菌Vibrio sp.。养殖系统中除水源的细菌浓度没有超标污染 (<50 cfu/mL)外,其余均检出了大量细菌 (>1 × 105 cfu/mL);病原来源较复杂：水源、养殖池水、池底污物、附着基板和饵料均发现了病原菌,但病原菌浓度以饵料中最多,附着基板次之,水源中最少。萘啶酸等12种常用抗生素可有效抑制该病原菌的生长。【结论】“化板症”的病原为弧菌Vibrio sp.;饵料可能为“化板症”病原的主要来源;萘啶酸等12种常用抗生素可用于该病的防治。     

An improved equation and assay for determining the CO2/O2 specificity for Rubisco

The determination of the CO₂/O₂ specificity factor (Ω) is very important to investigate the Rubisco carbon assimilation efficiency. In this paper, it is proved that previous formulae can introduce notable errors into calculating the CO₂/O₂ specificity factor (Ω) because CO₂ and O₂ are both the substrates and the mutually competitive inhibitors for Rubisco. A simple integrated equation is proposed to calculate the CO₂/O₂ specificity factor (Ω). On the other hand, previous multi-step procedures, including the manipulation of radioisotope (¹⁴C and/or ³H) and the chromatographic separation of the products, are inconvenient and may cause much random error. An improved assay procedure is presented therefore, which includes the spectrophotometric measurement of 3-phosphoglycerate-dependent NADH oxidation with a coupled enzyme system. This revised version was published online in June 2006 with corrections to the Cover Date.     

SCL,Encoding a Chloroplast Signal Recognition Particle Receptor,Affects Chlorophyll Synthesis and Chloroplast Development in Rice

Journal of Plant Growth Regulation - Crop yield is largely determined by the solar energy utilization efficiency of photosynthesis; plants with long stay-green periods have greater total...     

Effects of Pulsed 2.856 GHz Microwave Exposure on BM-MSCs Isolated from C57BL/6 Mice

The increasing use of microwave devices over recent years has meant the bioeffects of microwave exposure have been widely investigated and reported. However the exact biological fate of bone marrow MSCs (BM-MSCs) after microwave radiation remains unknown. In this study, the potential cytotoxicity on MSC proliferation, apoptosis, cell cycle, and in vitro differentiation were assayed following 2.856 GHz microwave exposure at a specific absorption rate (SAR) of 4 W/kg. Importantly, our findings indicated no significant changes in cell viability, cell division and apoptosis after microwave treatment. Furthermore, we detected no significant effects on the differentiation ability of these cells in vitro, with the exception of reduction in mRNA expression levels of osteopontin (OPN) and osteocalcin (OCN). These findings suggest that microwave treatment at a SAR of 4 W/kg has undefined adverse effects on BM-MSCs. However, the reduced-expression of proteins related to osteogenic differentiation suggests that microwave can the influence at the mRNA expression genetic level.     

Development of a PNA probe for fluorescence in situ hybridization detection of Prorocentrum donghaiense

Prorocentrum donghaiense is a common but dominant harmful algal bloom (HAB) species, which is widely distributed along the China Sea coast. Development of methods for rapid and precise identification and quantification is prerequisite for early-stage warning and monitoring of blooms due to P. donghaiense. In this study, sequences representing the partial large subunit rDNA (D1-D2), small subunit rDNA and internal transcribed spacer region (ITS-1, 5.8S rDNA and ITS-2) of P. donghaiense were firstly obtained, and then seven candidate DNA probes were designed for performing fluorescence in situ hybridization (FISH) tests on P. donghaiense. Based on the fluorescent intensity of P. donghaiense cells labeled by the DNA probes, the probe DP0443A displayed the best hybridization performance. Therefore, a PNA probe (PP0443A) analogous to DP0443A was used in the further study. The cells labeled with the PNA probe displayed more intensive green fluorescence than that labeled with its DNA analog. The PNA probe was used to hybridize with thirteen microalgae belonging to five families, i.e., Dinophyceae, Prymnesiophyceae, Raphidophyceae, Chlorophyceae and Bacillariophyceae, and showed no visible cross-reaction. Finally, FISH with the probes PP0443A and DP0443A and light microscopy (LM) analysis aiming at enumerating P. donghaiense cells were performed on the field samples. Statistical comparisons of the cell densities (cells/L) of P. donghaiense in the natural samples determined by FISH and LM were performed using one-way ANOVA and Duncan's multiple comparisons of the means. The P. donghaiense cell densities determined by LM and the PNA probe are remarkably higher than (p<0.05) that determined by the DNA probe, while no significant difference is observed between LM and the PNA probe. All results suggest that the PNA probe is more sensitive that its DNA analog, and therefore is promising for the monitoring of harmful algal blooms of P. donghaiense in the future.     

Pulsed High-Peak Power Microwaves at 9.4 GHz Do Not Affect Basic Endpoints in Caenorhabditis elegans

Because of the extensive application of electromagnetic technology, its health impact on humans has attracted widespread attention. Due to the lack of a model organism with a stable response to electromagnetic waves, the research conclusions on the biological effects of electromagnetic waves have been vague. Therefore, the aim of this study was to investigate the effects of irradiation by pulsed 9.4 GHz high-power microwaves with a peak power density of 2126 W/cm² using Caenorhabditis elegans. The development, movement, egg production, ROS, and lifespan of C. elegans were detected at different times after irradiation with different repetitive frequencies of 10, 20, and 50 Hz for 30 min. The results indicated that no obvious changes in basic life indices were induced compared with the sham radiation group, but the survival rate of positive control was significantly decreased compared with other groups, which is of interest for microwave protection research based on C. elegans and provides data for updating safety standards with respect to pulsed high-peak power microwave. © 2021 Bioelectromagnetics Society.