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51.
Abstract

The presence, in the North Adriatic sea and in the Chioggia and Marano lagoons, of Pseliodinium vaubanii a rare dinoflagellate species, is reported. Our results showed that Pseliodinium vaubanii is a very frequent and abundant species in these environments.  相似文献   
52.
A facultatively anaerobe, moderately halophilic, Gram-negative, filamentous, non motile and unpigmented bacterium, designated M30T, was isolated from coastal Mediterranean Sea water in Valencia, Spain. Phylogenetic analysis based on 16S rRNA sequences placed this strain in the phylum “Bacteroidetes” with Marinifilum fragile JC2469T as its closest relative with 97% sequence similarity. Average nucleotide identity (ANI) values between both strains were far below the 95% threshold value for species delineation (about 89% using BLAST and about 90% using MUMmer). A comprehensive polyphasic study, including morphological, biochemical, physiological, chemotaxonomic and phylogenetic data, confirmed the independent species status of strain M30T within the genus Marinifilum, for which the name Marinifilum flexuosum sp. nov. is proposed. The type strain of Marinifilum flexuosum is M30T (=CECT 7448T = DSM 21950T).  相似文献   
53.
李竞  侯丽朋  唐立娜 《生态学报》2021,41(22):8845-8859
改革开放以来,中国经济迅猛发展,但大气污染等环境问题日益突出。进入21世纪,我国通过颁布实施多项大气污染防治政策,将京津冀及周边地区、长三角地区、珠三角地区等大气污染较严重的区域划定为重点区域,针对性制定治污措施和实施减排工程,努力推动区域环境空气质量改善。基于2000-2019年我国31个省(自治区、直辖市)(以下简称31个省份)GDP,以及SO2、PM10、NO2三项大气污染物浓度数据,利用环境库兹涅茨曲线(EKC,Environmental Kuznets Curve)模型,对31个省份和京津冀及周边地区、长三角地区、珠三角地区的经济增长情况、大气污染物浓度演变以及二者之间的关系进行了系统全面的分析评估。研究结果显示:(1)近年来实施的各项大气污染防治政策,特别是2013年以来颁布实施的《大气污染防治行动计划》《打赢蓝天保卫战三年行动计划》,推动环境空气质量改善的同时,促进了经济发展与环境保护长期关系协调性逐步增强,除NO2浓度呈U型外,31个省份SO2浓度、PM10浓度与人均GDP的EKC曲线呈倒U型和倒N型,并处于快速下降阶段。(2)京津冀及周边地区SO2浓度与人均GDP呈倒U型,且处于快速下降阶段;PM10和NO2浓度均呈现U型关系,且均处于上升期。(3)长三角地区SO2、PM10浓度与人均GDP呈现倒U型和U型,但均处于下降阶段;NO2浓度与人均GDP无相关关系。(4)珠三角地区SO2、PM10和NO2浓度与人均GDP均呈现倒U型关系,且均处于下降阶段。为此,建议"十四五"期间我国政府要继续实施新一轮的大气污染防治行动计划,聚焦机动车NOx污染管控,大力推动NO2浓度稳步下降,以实现我国环境空气质量持续改善,为统筹经济高质量发展和生态环境高水平保护奠定坚实基础。  相似文献   
54.
马勇  凌旋  童昀 《生态学报》2021,41(19):7542-7554
以典型旅游城市三亚市为案例地,利用2006-2018年4期Landsat遥感影像数据,借助ENVI、ArcGIS平台定量识别土地利用演变特征,在1km×1km格网尺度下估算旅游地生态系统服务价值,并结合空间探索性数据分析揭示生态系统服务价值时空分异特征及其与旅游地发展的时空耦合关系。结果表明:(1)2006-2018年间,三亚市生态系统服务价值总量呈逐年下降趋势,由6.73×109元降至5.76×109元,累计减少9.78×108元;(2)空间格局上,三亚市呈"南低北高"空间分异格局,2006-2018年增值区域连片分布于崖州区、天涯区、吉阳区南部区域,且呈逐年减少趋势,减值区域集聚于天涯区东北部、海棠区;(3)空间集聚上,生态系统服务价值截面各年份均呈显著空间正相关且相关性先降后增。高高集聚区位于天涯区北部区域,低低集聚区分布于沿海、海湾地区;(4)旅游发展与生态系统服务价值时空演化特征关联性较强。三亚市天涯区北部林地生态环境良好,生态系统服务价值略有下降但绝对数值稳定,是生态系统服务价值主要来源;旅游发展较为迅速的三亚湾、崖州湾以及海棠湾,相对增值区域较多,但绝对生态系统服务价值损失显著,严重滞后于其他区域。  相似文献   
55.
56.
Distribution and magnitude of arsenic and metals in surface sediments collected from the coastal and estuarine areas of the southern Bohai Sea, China, were investigated. Sediments from the estuarine and coastal areas of the Jie and Xiaoqing Rivers contained highest concentrations of arsenic, cadmium, copper, mercury, and zinc. Mean concentrations of Cu, Zn, Cr, Pb, and Cd were higher than background concentrations determined for the areas. The magnitude of both enrichment factors (EF) and geoaccumulation indices (Igeo) suggested that pollution with As and metals was occurring along estuarine and coastal areas of the southern Bohai Sea. Risk analysis also suggested that concentrations of As and metals were sufficiently elevated as to cause adverse biological effects in the study area. According to the ecological risk index (RI) values, the upstream of the Jie River has a very high ecological risk for the waterbody. The data provided in this study are considered crucial for controlling and remediation of As and metals’ pollution of the southern Bohai Sea.  相似文献   
57.
58.
In spite of their potential importance in evolution, there is little information about Hox genes in animal groups that are related to ancestors of deuterostome. It has been reported that only two Hox genes (Hbox1 and Hbox7) are expressed significantly in sea urchin embryos. Expression of Hbox1 protein is restricted to the aboral ectoderm, and Hbox7 expression is restricted to oral ectoderm, endoderm and secondary mesenchyme cells in sea urchin embryos after the gastrula stage. With the aim of gaining insight into the role of Hbox1 and Hbox7 in sea urchin development, Hbox1 and Hbox7 overexpression experiments were performed. Overexpression of Hbox1 repressed the development of oral ectoderm, endoderm and mesenchyme cells. On the contrary, overexpression of Hbox7 repressed the development of aboral ectoderm and primary mesenchyme cells. The data suggest that Hbox1 and Hbox7 are expressed in distinct non-overlapping territories, and overexpression of either one inhibits territory-specific gene expression in the domain of the other. It is proposed that an important function of both Hbox1 and Hbox7 genes is to maintain specific territorial gene expression by each one, in its domain of expression, while repressing the expression of the other in this same domain.  相似文献   
59.
60.
The effect of bicuculline-induced convulsive seizures on lipid metabolism has been studied in four brain areas (cerebellum, cerebral cortex, hippocampus, and brainstem) using [2-3H]glycerol and [1,2-14C]ethanolamine as radioactive lipid precursors administered simultaneously with bicuculline. Twelve minutes after the administration, the uptake of radioactivity depended both on brain area and treatment, being generally higher in convulsing rats. The uptake of glycerol was influenced to a larger extent than that of ethanolamine and increased during convulsions, but its incorporation into lipids did not. In contrast, the amount of ethanolamine incorporated into lipids increased during bicuculline-induced seizures. The difference in behavior of glycerol and of ethanolamine is also indicated by the decrease of the 3H/14C ratio of phosphatidyl-ethanolamine in various brain areas during convulsions. It is, therefore, evident that the metabolism of the two precursors is affected differently by seizures.  相似文献   
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