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排序方式: 共有199条查询结果,搜索用时 31 毫秒
11.
Santini Nadia S. Lovelock Catherine E. Hua Quan Zawadzki Atun Mazumder Debashish Mercer Tim R. Muñoz-Rojas Miriam Hardwick Simon A. Madala Bindu Swapna Cornwell William Thomas Torsten Marzinelli Ezequiel M. Adam Paul Paul Swapan Vergés Adriana 《Ecosystems》2019,22(8):1803-1822
Ecosystems - Saltmarshes provide many valuable ecosystem services including storage of a large amount of ‘blue carbon’ within their soils. To date, up to 50% of the world’s... 相似文献
12.
Debashish Bhattacharya John Aubry Erik C. Twait Stefanie Jurk 《Journal of phycology》2000,36(5):813-820
Actin is a highly conserved cytoskeletal protein that is a key component of cells. Genes encoding actin occur in single copies in most green algae, in 2–3 copies in bryophytes, and in increasingly more complex gene families in ferns and seed plants. We use the well-resolved phylogenetic frameworks of the Streptophyta as a guide to reconstruct the patterns of actin gene duplication in early diverging land plants. Our working hypothesis is that the origin of novel tissues in the bryophytes (e.g. multicellular sporophyte) may be reflected in the functional diversification of duplicate actin genes in these taxa. Actin is used as a model cytoskeletal protein with the assumption that its evolutionary history represents those of other cytoskeletal elements and the coevolved binding proteins. Here we provide a phylogenetic perspective on the origin of green algal and land plant actin genes and use this information to speculate on the role of plant actin in early plant evolution. 相似文献
13.
Photosynthetic eukaryotes unite: endosymbiosis connects the dots 总被引:15,自引:0,他引:15
Bhattacharya D Yoon HS Hackett JD 《BioEssays : news and reviews in molecular, cellular and developmental biology》2004,26(1):50-60
The photosynthetic organelle of algae and plants (the plastid) traces its origin to a primary endosymbiotic event in which a previously non-photosynthetic protist engulfed and enslaved a cyanobacterium. This eukaryote then gave rise to the red, green and glaucophyte algae. However, many algal lineages, such as the chlorophyll c-containing chromists, have a more complicated evolutionary history involving a secondary endosymbiotic event, in which a protist engulfed an existing eukaryotic alga (in this case, a red alga). Chromists such as diatoms and kelps then rose to great importance in aquatic habitats. Another algal group, the dinoflagellates, has undergone tertiary (engulfment of a secondary plastid) and even quaternary endosymbioses. In this review, we examine algal diversity and show endosymbiosis to be a major force in algal evolution. This area of research has advanced rapidly and long-standing issues such as the chromalveolate hypothesis and the extent of endosymbiotic gene transfer have recently been clarified. 相似文献
14.
The Cyanidiales is a group of asexual, unicellular red algae, which thrive in acidic and high temperature conditions around hot springs. These unicellular taxa have a relatively simple morphology and are currently classified into three genera, Cyanidium, Cyanidioschyzon and Galdieria. Little is known, however, about the biodiversity of Cyanidiales, their population structure and their phylogenetic relationships. Here we used a taxonomically broadly sampled three-gene data set of plastid sequences to infer a robust phylogenetic framework for the Cyanidiales. The phylogenetic analyses support the existence of at least four distinct Cyanidiales lineages: the Galdieria spp. lineage (excluding Galdieria maxima), the Cyanidium caldarium lineage, a novel monophyletic lineage of mesophilic Cyanidium spp. and the Cyanidioschyzon merolae plus Galdieria maxima lineage. Our analyses do not support the notion of a mesophilic ancestry of the Cyanidiales and suggest that these algae were ancestrally thermo-acidotolerant. We also used environmental polymerase chain reaction (PCR) for the rbcL gene to sample Cyanidiales biodiversity at five ecologically distinct sites at Pisciarelli in the Phlegrean Fields in Italy. This analysis showed a high level of sequence divergence among Cyanidiales species and the partitioning of taxa based on environmental conditions. Our research revealed an unexpected level of genetic diversity among Cyanidiales that revises current thinking about the phylogeny and biodiversity of this group. We predict that future environmental PCR studies will significantly augment known biodiversity that we have discovered and demonstrate the Cyanidiales to be a species-rich branch of red algal evolution. 相似文献
15.
Debashish Bhattacharya 《Protist》1998,149(2):113-122
16.
17.
Phylogenomic analysis supports the monophyly of cryptophytes and haptophytes and the association of rhizaria with chromalveolates 总被引:3,自引:0,他引:3
Hackett JD Yoon HS Li S Reyes-Prieto A Rümmele SE Bhattacharya D 《Molecular biology and evolution》2007,24(8):1702-1713
Here we use phylogenomics with expressed sequence tag (EST) data from the ecologically important coccolithophore-forming alga Emiliania huxleyi and the plastid-lacking cryptophyte Goniomonas cf. pacifica to establish their phylogenetic positions in the eukaryotic tree. Haptophytes and cryptophytes are members of the putative eukaryotic supergroup Chromalveolata (chromists [cryptophytes, haptophytes, stramenopiles] and alveolates [apicomplexans, ciliates, and dinoflagellates]). The chromalveolates are postulated to be monophyletic on the basis of plastid pigmentation in photosynthetic members, plastid gene and genome relationships, nuclear "host" phylogenies of some chromalveolate lineages, unique gene duplication and replacements shared by these taxa, and the evolutionary history of components of the plastid import and translocation systems. However the phylogenetic position of cryptophytes and haptophytes and the monophyly of chromalveolates as a whole remain to be substantiated. Here we assess chromalveolate monophyly using a multigene dataset of nuclear genes that includes members of all 6 eukaryotic supergroups. An automated phylogenomics pipeline followed by targeted database searches was used to assemble a 16-protein dataset (6,735 aa) from 46 taxa for tree inference. Maximum likelihood and Bayesian analyses of these data support the monophyly of haptophytes and cryptophytes. This relationship is consistent with a gene replacement via horizontal gene transfer of plastid-encoded rpl36 that is uniquely shared by these taxa. The haptophytes + cryptophytes are sister to a clade that includes all other chromalveolates and, surprisingly, two members of the Rhizaria, Reticulomyxa filosa and Bigelowiella natans. The association of the two Rhizaria with chromalveolates is supported by the approximately unbiased (AU)-test and when the fastest evolving amino acid sites are removed from the 16-protein alignment. 相似文献
18.
Background
Horizontal gene transfer (HGT), the non-genealogical transfer of genetic material between different organisms, is considered a potentially important mechanism of genome evolution in eukaryotes. Using phylogenomic analyses of expressed sequence tag (EST) data generated from a clonal cell line of a free living dinoflagellate alga Karenia brevis, we investigated the impact of HGT on genome evolution in unicellular chromalveolate protists. 相似文献19.
The discovery of unanticipated microbial diversity in remote, often hostile environments has led to a greater appreciation of the complexity and richness of the natural world. Yellowstone National Park (YNP) has long been a focus of work on taxa that inhabit extreme environments. Here we report the finding of microbial flora that inhabit an unexpected niche: the cavities of bone remnants from a bison carcass in Norris Geyser Basin in YNP. Although bleached white on the surface, the bone cavities are bright green due to the presence of Stichococcus-like trebouxiophyte green algae. The cavities also harbour different fungi and bacteria. Stichococcus species are common lichen photobionts and the Thelebolales fungi present in the bone cavities have previously been found in association with animal remains. Scanning electron microscope analysis suggests the fungi and algae do not form lichen-like associations in the bone. Rather these taxa and the bacteria appear to be opportunists that have colonized an isolated oasis that provides nutrients and protection from desiccation and UV radiation. 相似文献
20.