青枯假单胞杆菌噬菌体ZP-2和ZP-3的生物学性状

噬菌体可作为检测和区分植物病原细菌的一种手段。有关青枯假单胞杆菌(Pseudomo-n~(as solanacearum) 噬菌体的研究工作报道不多,姜瘟菌株上的噬菌体则还未见报道。本文所报道的关于分离自土壤的青枯假单胞杆菌姜瘟菌株(ZO-12)的噬菌体ZP-2和ZP-3生物学性状的研究结果,可为这些噬菌体的利用提供参考依据。     

胚乳性状的遗传模型和世代平均数

谷类作物的胚乳是三倍体组织,胚乳性状受3N遗传控制。本文分析了胚乳性状的遗传特征,建立了相应的遗传模型,推导了世代群体的平均数分量,并提出了研究胚乳性状基因效应的一些简单的交配设计。     

The heart as an endocrine organ

Modern data on atrial natriuretic factor (ANF) are presented. Synthesis of this factor, its storage and release from cardiac atria are described. The role of ANF in the body fluid volume regulation and blood pressure homeostasis is discussed. ANF is regarded as a circulating hormone.     

小麦赤霉病的药剂防治指标模型

经过推导,得出小麦赤霉病的两类药剂防治指标模型．在保证品质、收支有余的条件下,第一类模型附加产投比较佳、净收益最佳原则,第二类模型附加产投比最佳原则．灵敏度分析和合理性分析证明了模型的正确性．模型可做为小麦赤霉病药剂防治的决策工具．同时,给出了两类模型的BASIC计算程序．     

旋扭山绿豆根瘤菌MXDI6菌株氢酶诱导表达

在自生异养条件下,旋扭山绿豆根瘤菌ＭＸＤＩ６菌株的氢酶诱导表达受气相、ｐＨ值、镍等因子影响：氢酶表达的最适氧浓度为４％,最适氢浓度为１５％,二氧化碳没有明显影响;氢酶表达的ｐＨ值以５．０—６．０为宜;０．５μｍｏｌ／ＬＮｉＣｌ２明显促进吸氢活性,但镍浓度大于１μｍｏｌ／Ｌ则抑制吸氢活性．     

山东省蚜虫名录

本是作1981-1993年对山东省蚜虫的调查结果,共记述12科,80属,184种和亚种及其寄主与分布,其中6种是中国新记录,97种是山东省新记录（右上角标记*）。     

Fine-scale mapping of physicochemical and microbial landscapes of the coral skeleton

The coral skeleton harbours a diverse community of bacteria and microeukaryotes exposed to light, O₂ and pH gradients, but how such physicochemical gradients affect the coral skeleton microbiome remains unclear. In this study, we employed chemical imaging of O₂ and pH, hyperspectral reflectance imaging and spatially resolved taxonomic and inferred functional microbiome characterization to explore links between the skeleton microenvironment and microbiome in the reef-building corals Porites lutea and Paragoniastrea benhami. The physicochemical environment was more stable in the deep skeleton, and the diversity and evenness of the bacterial community increased with skeletal depth, suggesting that the microbiome was stratified along the physicochemical gradients. The bulk of the coral skeleton was in a low O₂ habitat, whereas pH varied from pH 6–9 with depth. Physicochemical gradients of O₂ and pH of the coral skeleton explained the β-diversity of the bacterial communities, and skeletal layers that showed O₂ peaks had a higher relative abundance of endolithic algae, reflecting a link between the abiotic environment and the microbiome composition. Our study links the physicochemical, microbial and functional landscapes of the coral skeleton and provides new insights into the involvement of skeletal microbes in the coral holobiont metabolism.     

The distribution of coastal fish eDNA sequences in the Anthropocene

Aim

Coastal fishes have a fundamental role in marine ecosystem functioning and contributions to people, but face increasing threats due to climate change, habitat degradation and overexploitation. The extent to which human pressures are impacting coastal fish biodiversity in comparison with geographic and environmental factors at large spatial scale is still under scrutiny. Here, we took advantage of environmental DNA (eDNA) metabarcoding to investigate the relationship between fish biodiversity, including taxonomic and genetic components, and environmental but also socio-economic factors.

Location

Tropical, temperate and polar coastal areas.

Time period

Present day.

Major taxa studied

Marine fishes.

Methods

We analysed fish eDNA in 263 stations (samples) in 68 sites distributed across polar, temperate and tropical regions. We modelled the effect of environmental, geographic and socio-economic factors on α- and β-diversity. We then computed the partial effect of each factor on several fish biodiversity components using taxonomic molecular units (MOTU) and genetic sequences. We also investigated the relationship between fish genetic α- and β-diversity measured from our barcodes, and phylogenetic but also functional diversity.

Results

We show that fish eDNA MOTU and sequence α- and β-diversity have the strongest correlation with environmental factors on coastal ecosystems worldwide. However, our models also reveal a negative correlation between biodiversity and human dependence on marine ecosystems. In areas with high dependence, diversity of all fish, cryptobenthic fish and large fish MOTUs declined steeply. Finally, we show that a sequence diversity index, accounting for genetic distance between pairs of MOTUs, within and between communities, is a reliable proxy of phylogenetic and functional diversity.

Main conclusions

Together, our results demonstrate that short eDNA sequences can be used to assess climate and direct human impacts on marine biodiversity at large scale in the Anthropocene and can further be extended to investigate biodiversity in its phylogenetic and functional dimensions.     

Self-assembly of molecular beacons through metal ion coordination for fluorescence imaging of miRNA in living cells

Fluorescence nanosensors based on functional nucleic acids have been explored as a powerful sensing platform for disease-relevant miRNAs. This work developed a new hybrid nanosensor (Zr-B) through coordination-driven self-assembly of Zr ions and beacons. The prepared nanosensor exhibited high loading efficiency of beacons and could achieve sensitive and specific detection for miRNAs. The hybrid nanosensor could transfer beacons into living cells efficiently and maintain high stability and biocompatibility in the biological environment, achieving effective miRNA fluorescence imaging in living cells. Therefore, the resultant nanosensor holds potential for applications in disease diagnostics.