Diversity of bacterial community structure and its driving factors in three bays of Bohai Sea

[Background] Sustainable development of coastal ecosystem has become one of the most important concerns for people nowadays. Riverine output and anthropogenic interrupt have important impacts on the coastal environment. [Objective] In this study, we collected 12 samples from three transects including Bohai Bay, Liaodong Bay and Laizhou Bay to explore the microbial community and diversity in summer of 2015. [Methods] DNA was extracted from water samples by using DNA extraction kit. Samples were analyzed by Illumina HiSeq sequencing technology. We compared the differences among these three transects according to the analysis results. [Results] The diversity index and rarefaction curves showed significant differences among these three transects. The order of diversity value was Laizhou Bay>Bohai Bay>Liaodong Bay. The distribution of the dominant community was as follows: the proportion of Proteobacteria, Bacteroidetes, Cyanobacteria, Actinobacteria and Planctomycetes in the Bohai Bay was 39.8%, 25.7%, 22.4%, 5.85% and 4.38%, respectively. The dominant community proportion in Liaodong bay was Proteobacteria (37.8%), Bacteroidetes (25.7%), Cyanobacteria (17.8%), Actinobacteria (10.4%) and Planctomycetes (5.64%). While in Laizhou Bay there were only four dominant communities as follows: Proteobacteria (59.0%), Bacteroidetes (17.5%), Cyanobacteria (8.2%), Actinobacteria (7.88%). By using the principal component analysis (PCA) and Heatmap correlation analysis, we found that environmental factors were key roles in controlling the microbial diversity in the Bohai Sea. Among them, the concentration of nitrate was particularly significant according to the Mantel test analysis. [Conclusion] The microbial diversity in the three bays of Bohai Sea was very rich and multifarious. The population structure and species in the Laizhou Bay is the most complex and abundant among these three bays, and then it is Bohai Bay and Liaodong Bay. There was a significant correlation among microbial diversity, environmental factors and the spatial distribution. Above all, this study will provide a theoretical basis for further protection and ecological development of Bohai Sea

Distribution of the Net-Phytoplankton Community and Chlorophyll-a in the Bohai Sea in Summer and Its Impacts on Fishery Resources

Phytoplankton are the major primary producers in the ocean and play a crucial role in the marine food chain. Understanding the dynamics of the marine phytoplankton community can provide insights into the succession process and current status of marine fishery resources. Based on the net-phytoplankton samples collected from the Bohai Sea in the summer (June and August) of 2015, we studied the phytoplankton community composition, diversity, abundance, and dominant taxa in the Bohai Sea. Compared with historical data, the phytoplankton community structure in the Bohai Sea was changed markedly. The chlorophyll-a concentration had changed slightly during recent years, but was much higher than that in the 1980s and 1990s, and the regions with lower values (&lt;1.0 g/L) were much smaller than those 20 years ago. In terms of the dominant taxa, the dominance of the genera Chaetoceros and Coscίnodiscus was found to be slightly decreased, whereas the species Skeletonema costatum, which had been an important dominant species in the Bohai Sea, was not observed in the two months of summer in 2015. In contrast, Paralia sulcata and Pyrrophyta (Noctiluca scientillans in June and Ceratium tripos in August) were still dominant in the Bohai Sea, and the abundance and dominance of Achnanthes brevipes and Pseudo-nitzschia pungens was higher than those in the years before 2015. The diversity indices (Shannon diversity and species richness and evenness) of phytoplankton were at a moderate level. Such a trend was mainly caused by the significant change of the nutrient structure in the Bohai Sea. This may change the structure of the marine food chain and influence the growth and reproduction of commercial fishes and shrimps (e.g., Konosirus punctatus, Liza haematocheila, and Acetes chinensis) that feed on phytoplankton. Consequently, this will have potential impacts on fishery production and the structure and function of the ecosystem in the Bohai Sea.</p

Rhizosphere microbial community structure and function of Zostera japonica in the distribution area of seagrass beds in the Yellow Sea and Bohai Sea

Zostera japonica is a unique Asian seaweed species and has important ecological value. In recent years, Zostera japonica has been continuing to degenerate, causing widespread concern among researchers. [Objective] We hypothesized that the rhizospheric microorganisms were closely related with the healthy growth of Zostera japonica. We explored the diversity and function of microbial community in root of Zostera japonica at coastal zone of Yellow sea and Bohai sea, and intrinsic relationship with seagrass. [Methods] We collected surface sediment samples of Zostera japonica roots and unvegetated areas from three locations including Dongying, Weihai, and Dalian city. We investigated the rhizosphere microbial community structure by sequencing on Illumina HiSeq300 platform and analyzed the correlation between microbial community structure and environmental parameters. [Results] The most dominated phyla widely distributed in the rhizospheric surface sediments of Zostera japonica included: Proteobacteria (41.1%), Cyanobacteria (15.4%), Bacteroidetes (12.6%), Actinobacteria (9.3%). Comparisons of different regions (Weihai, Dongying, and Dalian) or sample types (rhizosphere vs. non-rhizosphere) showed significant differences in microbial communities, mainly due to the presence of sulfate-reducing bacteria and nitrogen-fixing bacteria found in the rhizosphere. Total nitrogen, total carbon, total organic carbon, clay, were all significantly correlated to rhizospheric bacterial community composition and distribution. [Conclusion] From a functional point of view, the differences between groups was mostly related to sulfur and nitrogen cycling, and sulfate reducing bacteria play a key role in maintaining the ecological health of Zostera japonica.</p

干旱半干旱地区蓼科4属植物的系统发育关系研究/Study on Phylogeny of Four Polygonaceae Genera from Arid and Semiarid Areas[J]

提取蓼科木蓼属（Atraphaxis）、沙拐枣属（Calligonum）、翅果蓼属（Parapteropyrum）和双翅果蓼属（Pteropy-rum）蓼科4属植物的总DNA,通过聚合酶链式反应（PCR）,扩增其叶绿体基因片段atpB-rbcL。atpB-rbcL基因间区长约900 bp,已被广泛应用于属间系统发育关系的研究。运用PAUP和Bayesian软件,通过最大简约法、最大似然法和贝叶斯分析,建立系统发育树结果显示：4属中沙拐枣属和双翅果蓼属存在最近亲缘关系;而特产于中国西藏的翅果蓼属和其他3属关系较远;另外,沙拐枣属下4个组中基翅组、刺果组和翅果组聚于一小进化枝下,与泡果组相区别

中国脑血管病临床管理指南（第2版）（节选）——第3章 脑血管病高危人群管理 Chinese Stroke Association Guidelines for Clinical Management of Cerebrovascular Diseases (Second Edition) (Except) ——Chapter Three Management of Patients at Hige-risk of Cerebrovascular Diseases

针对脑血管病的危险因素积极进行早期干预管理是减少脑血管病危害最有效的方法。本章节介绍脑血管病高危人群管理的推荐意见，包括对不可干预和可干预血管危险因素的控制，阿司匹林在缺血性卒中一级预防中的应用以及首次卒中风险评估等方面。 Abstract: Early intervention to manage the risk factors of cerebrovascular disease is the most effective way to reduce the harm of cerebrovascular diseases. This chapter presents recommendations for the management of populations at high risk for cerebrovascular disease, including control of non-interventionable and interventionable vascular risk factors, the use of aspirin in the primary prevention of ischaemic stroke, and the risk assessment of first-time stroke