共查询到20条相似文献，搜索用时 31 毫秒
1.
Melanie S. Adams Barbara Demmig-Adams Ruiqi Li Daniel Zarate Jingchun Li 《Marine Ecology》2020,41(6):e12618
Coral reefs’ high productivity has been attributed mainly to photosymbioses between the coral animal and algae of the family Symbiodiniaceae, with recognition that the host can increase algal photosynthesis by concentrating nutrients and enhancing the efficiency of light absorption. Here, we propose that an additional effect, consumption of carbohydrate by the host, may also enhance algal photosynthesis. We examine evidence from symbiosis between terrestrial plants and root fungi that indicates a link between carbohydrate consumption by the symbiotic partner and photosynthetic upregulation in the plant system. In addition, we review evidence from free-living algae manipulated to exude carbohydrate into the external medium, which was associated with strong upregulation of photosynthetic capacity. We offer suggestions on how host-induced carbohydrate release may increase photosynthesis rates in the symbionts in the intact photosymbiosis and how this relationship evolved. 相似文献
2.
利用噬菌体治疗水产养殖细菌病害具有专一性强、自我增殖能力强等优点, 可以有效减少对环境的污染。为了获得可防治水产病原体溶藻弧菌(Vibrio alginolyticus)的生物杀菌剂, 本研究以Vibrio alginolyticus ATCC 17749T为宿主, 从福建省东山岛的对虾养殖场与水产市场污水环境中分离得到两株巨型噬菌体vB_ValM_R10Z和vB_ValM_R11Z, 并分别从噬菌体形态、宿主范围、生命周期和基因组信息等方面进行了鉴定和分析。实验结果显示, 噬菌体R10Z和R11Z具有相似的噬菌斑形态和电镜形态, 属于肌尾噬菌体; 除宿主之外, 噬菌体R10Z和R11Z均能侵染另一株欧文氏弧菌Vibrio owensii JL3186; 两株噬菌体均对氯仿不敏感, 表明其衣壳蛋白不含脂类物质; 噬菌体R10Z和R11Z的潜伏期均为20min, 但裂解量却相差一倍, 分别为45PFU·cell-1和114PFU·cell-1; 两株噬菌体的基因组大小分别为247167bp和246831bp, G+C含量分别为41.30%和41.33%, 两者基因组相似性达99.45%, 均未检测出毒力基因与抗药性基因; 系统发育分析显示两株噬菌体均属于Myoviridae(科), Tevenvirinae(亚科), Schizotequatrovirus(属), 同源基因在环境中分布广泛。两株噬菌体性状优良, 在水产病害的噬菌体治疗领域具有重要的研究价值和潜在的应用价值。 相似文献
3.
Phylogenomic analysis of transcriptomic sequences of mitochondria and chloroplasts of essential brown algae (Phaeophyceae) in China 总被引：1，自引：1，他引：0
JIA Shangang WANG Xumin LI Tianyong QIAN Hao SUN Jing WANG Liang YU Jun REN Lufeng YIN Jinlong LIU Tao WU Shuangxiu 《海洋学报(英文版)》2014,33(2):94-101
The chloroplast and mitochondrion of brown algae （Class Phaeophyceae of Phylum Ochrophyta） may have originated from different endosymbiosis. In this study, we carried out phylogenomic analysis to distinguish their evolutionary lineages by using algal RNA-seq datasets of the 1 000 Plants （1KP） Project and publicly available complete genomes of mitochondria and chloroplasts of Kingdom Chromista. We have found that there is a split between Class Phaeophyceae of Phylum Ochrophyta and the others （Phylum Cryptophyta and Haptophyta） in Kingdom Chromista, and identified more diversity in chloroplast genes than mitochondrial ones in their phylogenetic trees. Taxonomy resolution for Class Phaeophyceae showed that it was divided into Laminariales-Ectocarpales clade and Fucales clade, and phylogenetic positions of Kjellmaniella crassi-folia, Hizikia fusifrome and Ishige okamurai were confirmed. Our analysis provided the basic phylogenetic relationships of Chromista algae, and demonstrated their potential ability to study endosymbiotic events. 相似文献
4.
Phylogenomic analysis of transcriptomic sequences of mitochondria and chloroplasts for marine red algae (Rhodophyta) in China 总被引：1，自引：1，他引：0
JIA Shangang WANG Xumin QIAN Hao LI Tianyong SUN Jing WANG Liang YU Jun LI Xingang YIN Jinlong LIU Tao WU Shuangxiu 《海洋学报(英文版)》2014,33(2):86-93
The chloroplast and mitochondrion of red algae （Phylum Rhodophyta） may have originated from different endosymbiosis. In this study, we carried out phylogenomic analysis to distinguish their evolutionary lin-eages by using red algal RNA-seq datasets of the 1 000 Plants （1KP） Project and publicly available complete genomes of mitochondria and chloroplasts of Rhodophyta. We have found that red algae were divided into three clades of orders, Florideophyceae, Bangiophyceae and Cyanidiophyceae. Taxonomy resolution for Class Florideophyceae showed that Order Gigartinales was close to Order Halymeniales, while Order Graci-lariales was in a clade of Order Ceramials. We confirmed Prionitis divaricata （Family Halymeniaceae） was closely related to the clade of Order Gracilariales, rather than to genus Grateloupia of Order Halymeniales as reported before. Furthermore, we found both mitochondrial and chloroplastic genes in Rhodophyta under negative selection （Ka/Ks〈1）, suggesting that red algae, as one primitive group of eukaryotic algae, might share joint evolutionary history with these two organelles for a long time, although we identified some dif-ferences in their phylogenetic trees. Our analysis provided the basic phylogenetic relationships of red algae, and demonstrated their potential ability to study endosymbiotic events. 相似文献
5.
The authors have investigated the biochemical events by which marine algal virus infection induces cell cycle arrest. The key G2/M-phase regulatory proteins are analyzed by immunobloting in unicellular Emiliania huxleyi, suggesting that virus induced cell cycle arrest is related with virus''s effect on cyclins and cyclin dependent kinases. E. huxleyi virus (EhV) represses Cdc2/cyclinB complex activity by inhibiting the activity of Cdc2 kinase in a phosphorylation-related manner, blocking host cells G2/M checkpoint. Dephosphorylated/inactive Cdc25C combined with up-regulation of Wee1 expression at early infect period appears to be important mechanisms by which EhV represses Cdc2/cyclinB complex activity that is required for entry into M phase. This study has allowed us to confirm that algal virus infection leads to selective activation or inhibition of certain cell-cycle factors, which may play a significant role in establishing a more efficient environment for viral gene expression and DNA replication. 相似文献
6.
The mechanisms maintaining community structure following an ecosystem shift are poorly understood and we propose that they must inherently be biological. Over-exploitation can provide a “natural experiment” with man as a predator driving a change in community structure, possibly an ecosystem shift. We examined a possible mechanism that maintains algal beds as an alternative state on the east coast of South Africa where the mussel Perna perna has been overexploited. Even on unexploited shores, about 50% of mussel larvae settle onto algae, but it is unclear whether they later recruit into adult beds. On such shores we used two indirect field approaches to understand the fate of recruits, testing whether inhibition of mussel recruitment by macroalgae could constitute a biological mechanism preventing reversion from the algal to the pre-disturbance mussel-dominated state. First, we examined possible ontogenetic migration of recruits from algae to adult mussels, testing the prediction that the ratio large:small recruits in adult beds is greater where algae are liberally interspersed with mussels. Second, we examined whether, like adults, recruits show spatial structure that is related to the distribution of topographic depressions, testing the hypothesis that large and small recruits show different co-variation with depressions, microhabitats where algae commonly occur. We found no evidence that recruits on algae actively move to nearby mussel beds as neither the ratio large:small recruits nor the abundances of small or large recruits showed any relationship with algal cover/variability. Small and large recruits showed different co-variation with topographic depressions on spatially structured transects. Like adults, large recruits commonly exhibited negative relationships with depressions. Thus, large recruits neither occur on algae nor migrate from algae to the primary substratum or onto adult beds. Consequently our results (a) highlight the importance of post-settlement mortality in structuring these mussel populations, and (b) suggest that the interception of larvae by algae forms a biological mechanism that can maintain macroalgal beds that develop following exploitative disturbance by man, thus preventing or at least drastically delaying the natural recovery of mussel beds. 相似文献
7.
Sofia Loureiro Albert Reñé Esther Garcés Jordi Camp Dolors Vaqué 《Journal of Sea Research》2011,65(4):401-413
The surface microalgal community, including harmful species, dissolved organic matter (DOM), and bacterial and viral populations were studied during an annual cycle (November 2007–October 2008) in a Near-shore (NS) and a Harbour (H) station located in an upwelling area (Sagres, SW Iberian Peninsula). The higher water residence time, water stability and shallowness of harbours in comparison with open waters likely contributed to the differences found between stations regarding chemical variables, statistical correlations and harmful algal proliferations. Also, several differences were noticed from a previous assessment (Loureiro et al., 2005) including higher SST, lower nitrate and chlorophyll a concentrations, along with a shift in the microplankton community structure from diatom to nanoflagellate predominance. These variations feasibly reflect the response of this dynamic system to regional environmental modifications contributing to the understanding of common patterns in environmental change trends. The division of the sampling period into (1) non-upwelling (Non-Uw), (2) “spin-up” of upwelling (SU-Uw), and (3) “spin-down” and relaxation-downwelling (SD-Rel) stages allowed the identification of natural groupings of microplankton samples by Multi Dimensional Scaling (MDS) analysis. Dissolved organic nitrogen (DON) and viruses were the most significant abiotic and biotic variables, respectively, contributing to the dissimilarities between these stages (SIMPER analysis) and, therefore, potentially affecting the microplankton community structure. Harmful algal species and a stable viral community appeared to be favoured by SD-Rel conditions. Data seem to indicate that both Gymnodinium catenatum and Heterosigma akashiwo, the most abundant potentially harmful species, have been imported into the sampling area. Also, the H location, together with potential retention sites developing around the Cabo de São Vicente upwelling centre, may contribute to the local accumulation of harmful species. The associations found between harmful algal species and bacterioplankton and virioplankton call for detailed studies in order to evaluate species-specific interactions. 相似文献
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对2 组光倒刺鲃(Spinibarbus hollandi)杂交子一代(长江♀×北江♂子一代, 北江♀×长江♂子 一代)及其亲本(北江♀、♂, 长江♀、♂)的线粒体COI 基因序列进行了分析。在18 个样品中共检测到 8 个单倍型和35 个核苷酸多态位点。通过序列差异分析和遗传距离比较发现, 核苷酸序列同源性在 98.1%-99.9%之间, 遗传分化不明显。杂交子一代的5 个单倍型与其母本的2 个单倍型的核苷酸同 源性在99.4%-99.8%之间。而与父本的同源性分别为98.5%、98.2%、98.2%、98.4%、98.1%.实验 结果表明两种杂交子一代的线粒体 COI 基因严格遵循母性遗传规律。 相似文献
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坛紫菜品系间遗传差异的RAPD分析 总被引：10，自引：1，他引：9
Liu Biqian 《中国海洋大学学报(自然科学版)》2000,30(Z1):225-229
利用RAPD技术对六个坛紫菜品系进行了研究,从107条随机引 物中筛选10条随机引物,一共扩增出93条可重现的片段。经统计分析,六个品系间的遗传相 似系数在0.246～0.636之间。其中浙江北部沿海栽培品系间的相似系数最高为0.636.地 域间品系的遗传相似系数最低为0.246。六个品系用UPGMA方法得到的聚类关系符合传统的地 域和表型关系。通过对照品系间有稳定差异的DNA条带,表明RAPD标记是坛紫菜品系鉴定和 遗传多样性分析的有效手段。 相似文献
12.
溶藻细菌MS7的分类鉴定及其溶藻活性的初步研究 总被引：1，自引：0，他引：1
采用形态学、生理生化指标和16SrRNA基因序列同源性分析的方法,对菌株MS7进行鉴定,并通过溶藻试验测定该菌株对铜绿微囊藻(Microcystis aeruginosa)的溶藻活性和溶藻方式。结果表明,MS7菌株为苏云金芽孢杆菌(Bacillus thuringiensis),对铜绿微囊藻具有高效溶藻效果,当菌浓度为108cells/mL,初始藻液叶绿素a浓度为0.7mg/L时,48h溶藻率达到91%。主要通过分泌胞外物质的间接方式溶藻,溶藻物质属于具有很强的热稳定性的非蛋白质类物质。 相似文献
13.
The problem of recognition of algal genera based on the remote sensing data requires the analysis of the algae biomass’s distribution.
This study provides the analysis of the algae spatial and temporal variations in the Peter the Great Bay. While 116 algal
genera were observed, only a few genera have dominated. Usually, the dominant genus contributed about 60% of the sample’s
biomass (the minimal value is 20% usually) and 4 dominant genera contributed about 90% of the total phytoplankton biomass.
The effective scattering crosssection of the algae in the samples is very changeable and this feature looks promising for
the recognition problem. It was found that the spatial and temporal variations of the algal biomass are significant, but the
percentage characteristics of a few dominant genera are relatively stable with no significant dependence on a region and a
biomass value. The algae’s composition analysis has demonstrated that the same algal genera are propagated in different parts
of the Bay. For a given region and month, the set of algae dominated that constitutes about 90% of the monthly biomass is
rather small (not more than 10 genera usually). Most of the alga genera (∼75%) do not ever reach a mono domination state (more
than 50% of the sample’s biomass). 相似文献
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Pyrosequencing reveals specific associations of bacterial clades Roseobacter and Flavobacterium with the harmful dinoflagellate Cochlodinium polykrikoides growing in culture 
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下载免费PDF全文 Harmful algal blooms of the dinoflagellate Cochlodinium polykrikoides are of worldwide environmental concern. Previous field studies have demonstrated the association of such algal blooms with free‐living bacteria (FLB) and particle‐associated bacteria (PAB). In the present study, we report evidence for bacterial association with C. polykrikoides in laboratory culture. Sampling was performed at different growth stages (lag, exponential and stationary) and pyrosequencing was used to identify taxa. As a result, the community structures of FLB and PAB were elucidated and significant differences between FLB and PAB were identified by hierarchical cluster analysis and the similarity profiles test (p = .05). The relative abundances of bacterial operational taxonomic units distinctly changed in response to the different phases of C. polykrikoides growth. The Roseobacter genus Marivita and the Flavobacterium genus Winogradskyella were dominant in the FLB and PAB associated with C. polykrikoides, respectively. The Roseobacter clade, which has also exhibited associations with C. polykrikoides blooms in field samples, may influence host cell growth through the provision of vitamins. 相似文献
16.
On rocky shores, the relative importance of abiotic and biotic processes that regulate community structure are thought to vary with levels of shore exposure. This can lead to characteristic features found on sheltered and exposed shores. This study identified differences in the population structure of mussels on exposed and sheltered rocky shores on Atlantic coasts of south-west Ireland. Direct interactions between epibiotic algae and their host mussels were also examined to test if potential effects varied with shore exposure. Mussel beds on sheltered shores were less dense and comprised larger mussels with greater rates of individual survival and growth than those on exposed shores. The results of a field experiment showed that algal epibionts had a negative effect on mussel survival on sheltered shores but not on exposed shores. Surprisingly, the presence of algal epibionts had no effect on mussel growth on either shore type. These findings contrast with those of previous studies. The effects of shore exposure and algal epibionts on mussels may be species-specific and may interact with other factors across different regions. This study shows that predictions of effects of exposure on mussel populations and their epibionts should only be based on specific experimental evidence and cannot be generalised across regions. 相似文献
17.
海藻共附生细菌密切参与宿主的生长发育、营养吸收等重要过程,浒苔(Ulva prolifera)是构成黄海绿潮的唯一优势种,对其共附生细菌开展群落结构分析,有望为成灾机制研究提供重要线索。由于植物叶绿体基因组同时具备原核特征和高拷贝数,会严重干扰共附生细菌基于16S rDNA的序列扩增。高等植物中开发了通用引物799F,利用其3′末端与植物同源区的非配对双碱基,可实现对细菌来源序列的特异性扩增。本文针对多个浒苔群体样本,首次评价了引物799F在藻类中的适用性,发现799F的3′末端与浒苔叶绿体同源区仅存在非配对单碱基,其扩增仍会受到浒苔叶绿体严重干扰。在引物799F的基础上,设计了新引物800F,与通用反向引物1492R配对扩增细菌16S rDNA中具高分辨率的V5-V9可变区,配合使用具热启动功能、同时不具校对功能的DNA聚合酶,可基本完全避免浒苔叶绿体来源序列的扩增,并阐明了方法的原理。优化的引物扩增方案可用于浒苔共附生细菌群落结构分析。 相似文献
18.
在理论上改性黏土絮凝体的形态变化对其除藻过程有指示作用,可作为改性黏土用量和用法调控的依据,本文探讨了现有絮凝颗粒形态学观测与分析方法在改性黏土除藻效率评价上的适用性。借助激光颗粒表征技术和电子显微成像技术,本文观测了改性黏土除藻时的颗粒表面电性、粒径分布、絮凝体结构等絮凝形态学特征,分析了其与除藻效率的相关性。结果表明,现有观测方法可以表征改性导致的黏土颗粒Zeta电位反转、改性前后黏土在不同介质中的颗粒粒级分布差异、以及改性黏土与微藻形成絮凝体的多种显微结构;但由于较大粒径絮体对现有方法观测结果的影响更大,各种黏土的粒径特征与其除藻效率之间没有显著的相关性。现有观测方法获得的改性黏土颗粒形态特征仍不能反映其消除藻细胞的精细过程,特别是由于缺乏有效的絮凝体形态分析方法而导致现有形态参数还不能指示除藻效率的变化,亟需发展适用于改性黏土法除藻过程的颗粒形态分析新方法。 相似文献
19.
《African Journal of Marine Science》2013,35(3):545-549
The primary-secondary settlement hypothesis, that mussels first settle in algae and then move to mussel beds, was rejected as the only mode of recruitment for the brown mussel Perna perna in a previous study at one location over one year on the south coast of South Africa. We investigated recruitment of P. perna into mussel beds and algal turfs over a five-year period (1995–2000) at 3–4 sites at each of four locations on the South and East coasts. Attachment to the two substrata was significantly temporally synchronous at two of the four locations. The disparity among locations could be due to differences in the algal species present or to differences in the importance of turf algae as a facilitator of recruitment. At Zululand, on the East Coast, attachment to mussel beds and algae was measured monthly and found not to be temporally synchronous. At this location, primary settlement into algae was significantly correlated with an increase in the density of juveniles in the mussel beds 2–3 months later, indicating that turf algae can act as irregular but important facultative facilitators of mussel recruitment, supplementing direct input into the mussel beds. However, as amounts of settlers and recruits in mussel beds exceeded those found in algal turfs most years and places, the primary-secondary settlement hypothesis is inapplicable to P. perna under most circumstances. 相似文献
20.
Mangrove forests, important tropical coastal habitats, are in decline worldwide primarily due to removal by humans. Changes to mangrove systems can alter ecosystem properties through direct effects on abiotic factors such as temperature, light and nutrient supply or through changes in biotic factors such as primary productivity or species composition. Despite the importance of mangroves as transitional habitats between land and sea, little research has examined changes that occur when they are cleared. We examined changes in a number of biotic and abiotic factors following the anthropogenic removal of red mangroves (Rhizophora mangle) in the Panamanian Caribbean, including algal biomass, algal diversity, algal grazing rates, light penetration, temperature, sedimentation rates and sediment organic content. In this first study examining multiple ecosystem-level effects of mangrove disturbance, we found that areas cleared of mangroves had higher algal biomass and richness than intact mangrove areas. This increase in algal biomass and richness was likely due to changes in abiotic factors (e.g. light intensity, temperature), but not biotic factors (fish herbivory). Additionally the algal and cyanobacterial genera dominating mangrove-cleared areas were rare in intact mangroves and included a number of genera that compete with coral for space on reefs. Interestingly, sedimentation rates did not differ between intact and cleared areas, but the sediments that accumulated in intact mangroves had higher organic content. These findings are the first to demonstrate that anthropogenic clearing of mangroves changes multiple biotic and abiotic processes in mangrove forests and that some of these changes may influence adjacent habitats such as coral reefs and seagrass beds. Additional research is needed to further explore the community and ecosystem-level effects of mangrove clearing and their influence on adjacent habitats, but it is clear that mangrove conservation is an important aspect of managing tropical coastal systems. 相似文献