Fingerprint Dive into the research topics of Expression and regulation of carbonic anhydrases in the marine diatom Thalassiosira pseudonana and in natural phytoplankton assemblages from Great Bay, New Jersey. Together they form a unique fingerprint. ...
difference: plants are multicellular, diatoms are unicellular, plants reproduce by meiosis where as diatoms by cell division, most plants live on land where as diatoms strictly live in wet environment. plants are more complex and larger whereas diatoms are smaller (microscopic), there are out layer differences: plants have cell wall made of cellulose where as diatoms have cell wall made of silica, plants dont form colonies where as diatoms can form colonies, also there is chlorophyll (pigment) differences: plants usually have green chlorophyll whereas diatoms have yellow and brown pigments, some diatoms are capable of movement where as plants can move, and some diatoms are heterotrophic where as plants are strictly autotrophic. diatoms have different life cycles (alteration of generation), diatoms reproduce asexually by mitosis. diatoms fossilize when they die as rocks at the bottom of water, plants normally get eaten by decomposers. diatoms are more closely related to bacteria where as plants ...
BackgroundDiatoms are unicellular algae responsible for approximately 20% of global carbon fixation. Their evolution by secondary endocytobiosis resulted in a complex cellular structure and metabolism compared to algae with primary plastids.Methodology/Principal FindingsThe whole genome sequence of the diatom Phaeodactylum tricornutum has recently been completed. We identified and annotated genes for enzymes involved in carbohydrate pathways based on extensive EST support and comparison to the whole genome sequence of a second diatom, Thalassiosira pseudonana. Protein localization to mitochondria was predicted based on identified similarities to mitochondrial localization motifs in other eukaryotes, whereas protein localization to plastids was based on the presence of signal peptide motifs in combination with plastid localization motifs previously shown to be required in diatoms. We identified genes potentially involved in a C4-like photosynthesis in P. tricornutum and, on the basis of sequence-based
Macronutrients such as nitrogen (N), phosphorus (P), and silicon (Si) are essential for the productivity and distribution of diatoms in the ocean. Responses of diatoms to a particular macronutrient deficiency have been investigated, however, we know little about their common or specific responses to different macronutrients. Here, we investigated the physiology and quantitative proteomics of a diatom Thalassiosira pseudonana grown in nutrient-replete, N-, P-, and Si-deficient conditions. Cell growth was ceased in all macronutrient deficient conditions while cell volume and cellular C content under P- and Si-deficiencies increased. Contents of chlorophyll a, protein and cellular N decreased in both N- and P-deficient cells but chlorophyll a and cellular N increased in the Si-deficient cells. Cellular P content increased under N-and Si-deficiencies. Proteins involved in carbon fixation and photorespiration were down-regulated under all macronutrient deficiencies while neutral lipid synthesis and ...
Despite the importance of dimethylsulphoniopropionate (DMSP) in the global sulphur cycle and climate regulation, the biological pathways underpinning its synthesis in marine phytoplankton remain poorly understood. The intracellular concentration of DMSP increases with increased salinity, increased light intensity and nitrogen starvation in the diatom Thalassiosira pseudonana. We used these conditions to investigate DMSP synthesis at the cellular level via analysis of enzyme activity, gene expression and proteome comparison. The activity of the key sulphur assimilatory enzyme, adenosine 5′-phosphosulphate reductase was not coordinated with increasing intracellular DMSP concentration. Under all three treatments coordination in the expression of sulphur assimilation genes was limited to increases in sulphite reductase transcripts. Similarly, proteomic 2D gel analysis only revealed an increase in phosphoenolpyruvate carboxylase following increases in DMSP concentration. Our findings suggest that increased
Marine diatoms have recently gained much attention as they are expected to be a promising resource for sustainable production of bioactive compounds such as carotenoids and biofuels as a future clean energy solution. To develop photosynthetic cell factories, it is important to improve diatoms for value-added products. In this study, we utilized UVC radiation to induce mutations in the marine diatom Phaeodactylum tricornutum and screened strains with enhanced accumulation of neutral lipids and carotenoids. Adaptive laboratory evolution (ALE) was also used in parallel to develop altered phenotypic and biological functions in P. tricornutum and it was reported for the first time that ALE was successfully applied on diatoms for the enhancement of growth performance and productivity of value-added carotenoids to date. Liquid chromatography-mass spectrometry (LC-MS) was utilized to study the composition of major pigments in the wild type P. tricornutum, UV mutants and ALE strains. UVC radiated strains
Citation. Smith SR, Glé C, Abbriano RM, Traller JC, Davis A, Trentacoste E, Vernet M, Allen AE, Hildebrand M. Transcript Level Coordination of Carbon Pathways During Silicon Starvation-induced Lipid Accumulation in the Diatom Thalassiosira Pseudonana.. The New Phytologist. 2016 Feb 04;. External Citation. Abstract. Diatoms are one of the most productive and successful photosynthetic taxa on Earth and possess attributes such as rapid growth rates and production of lipids, making them candidate sources of renewable fuels. Despite their significance, few details of the mechanisms used to regulate growth and carbon metabolism are currently known, hindering metabolic engineering approaches to enhance productivity. To characterize the transcript level component of metabolic regulation, genome-wide changes in transcript abundance were documented in the model diatom Thalassiosira pseudonana on a time-course of silicon starvation. Growth, cell cycle progression, chloroplast replication, fatty acid ...
Dissolution of the frustule in water is minimized because it is surrounded by an organic casing that includes glycoproteins with high levels of rhamnose and xylose, two sugars rarely found in other eukaryotic glycans. Based on the presence of highly conserved calcium-binding domains (30), four new frustulins (casing glycoproteins) were identified, but no pleuralins, which are associated with terminal girdle bands in C. fusiformis (31). Consistent with a high content of hydroxylated amino acids found in the organic casing (32), one of the more abundant gene families in T. pseudonana encodes prolyl-4 hydroxylases.. Staying afloat. Diatoms must compensate for their dense silica frustule to maintain position within the illuminated portion of the water column. Some diatoms, including members of Thalassiosira, apparently increase drag and thus decrease sinking rates by extruding chitin fibers from pores in the frustule (24). These fibers can represent as much as 40% of total cell biomass and 20% of ...
Dissolution of the frustule in water is minimized because it is surrounded by an organic casing that includes glycoproteins with high levels of rhamnose and xylose, two sugars rarely found in other eukaryotic glycans. Based on the presence of highly conserved calcium-binding domains (30), four new frustulins (casing glycoproteins) were identified, but no pleuralins, which are associated with terminal girdle bands in C. fusiformis (31). Consistent with a high content of hydroxylated amino acids found in the organic casing (32), one of the more abundant gene families in T. pseudonana encodes prolyl-4 hydroxylases.. Staying afloat. Diatoms must compensate for their dense silica frustule to maintain position within the illuminated portion of the water column. Some diatoms, including members of Thalassiosira, apparently increase drag and thus decrease sinking rates by extruding chitin fibers from pores in the frustule (24). These fibers can represent as much as 40% of total cell biomass and 20% of ...
Diatoms are responsible for ∼40% of marine primary production and are key players in global carbon cycling. There is mounting evidence that diatom growth is influenced by cobalamin (vitamin B12) availability. This cobalt-containing micronutrient is only produced by some bacteria and archaea but is required by many diatoms and other eukaryotic phytoplankton. Despite its potential importance, little is known about mechanisms of cobalamin acquisition in diatoms or the impact of cobalamin scarcity on diatom molecular physiology. Proteomic profiling and RNA-sequencing transcriptomic analysis of the cultured diatoms Phaeodactylum tricornutum and Thalassiosira pseudonana revealed three distinct strategies used by diatoms to cope with low cobalamin: increased cobalamin acquisition machinery, decreased cobalamin demand, and management of reduced methionine synthase activity through changes in folate and S-adenosyl methionine metabolism. One previously uncharacterized protein, cobalamin acquisition ...
Altogether, diatoms are aptly referred to as jewels of the sea. Fabergés finest creations pale in comparison to those of the Creator!. Diatom shell structure is species specific; i.e., all organisms of the same species have essentially the same shell shape and infrastructure (though there are minor individual variations, so that no two diatoms are exactly alike), but the pattern is different for each species. Thus, as a character of taxonomic significance, it may be inferred that diatom shell structure is determined, ultimately, by genetic information. Meanwhile, the geometric diversity displayed appears to be non-adaptational-i.e., undiminished by natural selection. This is beauty for its own sake, unfettered by evolutionary pragmatism!. Nonetheless, for all their aesthetic qualities, diatoms are also a practical environmental resource. As photosynthetic autotrophs, they manufacture their own nutrition, which in turn represents a substantial percentage of the earths annual production of ...
Pathogenic bacteria, such as multidrug-resistant Staphylococcus aureus (MRSA), which are not susceptible to most conventional antibiotics, are causing increased concern in healthcare institutions worldwide. The discovery of novel antibacterial compounds for biomedical exploitation is one avenue that is being pursued to combat these problematic bacteria. Marine eukaryotic microalgae are known to produce numerous useful products but have attracted little attention in the search for novel antibiotic compounds. Cell lysates of the marine diatom, Phaeodactylum tricornutum Bohlin, have been reported to display antibacterial activity in vitro, but the compounds responsible have not been fully identified. In this paper, using column chromatography and reversed-phase high-performance liquid chromatography, we report the isolation of an antibacterial fatty acid. Mass spectrometry and 1H-nuclear magnetic resonance spectroscopy revealed it to be the polyunsaturated fatty acid, eicosapentaenoic acid (EPA). ...
Coloured scanning electron micrograph (SEM) of pennate (Diatoma sp.) and centric (Coscinodiscus sp.) marine diatom frustules (skeletons). These marine diatoms are found in both brackish and salt water. Diatoms are a type of algae (Chromophyta, Bacillariophyceae). They consist of two valves, made of silica (hydrated silicon dioxide), which fit together like the top and bottom of a box. The exterior of the valves are often highly decorative, with pores, spikes or other types of projections. They are important alga in the marine food chain. Magnification: x345 when shortest axis printed at 25 millimetres. - Stock Image C032/1247
There is significant interest in utilizing microalgae as a source for biofuels. Diatoms are a class of single-celled microalgae which make silica cell walls and require dissolved silicon as a substrate for cell division. Manipulation of soluble silicon delivery to the culture offers a route to control cell cycle and lipid production. A two-stage, semi-continuous photobioreactor cultivation process was developed to induce the production of lipid-rich algal biomass from the centric diatom Cyclotella sp. In Stage I of the process, algal cells were grown up to high density until all of the dissolved silicon in the feed medium was consumed. The cells were in the silicon-starved state when the cell density was constant for 24 hours and the dissolved silicon concentration was near-zero and ceased to change. In Stage II, fresh medium containing dissolved silicon was perfused into the reactor for a 48, 72 or 96 hours. The silicon was rapidly consumed by the silicon-starved cells under a surge uptake ...
Marine microalgae are key primary producers responsible for more than 45% of global net primary production, fixing billions of tons of inorganic carbon each year. Diatoms constitute one of the most diverse and ecologically important group of microalgae. While diatom productivity and health are likely to be strongly governed by the structure and function of the diatom microbiome, we have little understanding which factors contribute to the microbiome assembly. In order to investigate the microbiome establishment on diatoms, an in vitro model system for reproducible laboratory studies was developed with the marine diatom Thalassiosira rotula. Thus, this thesis describes the isolation of diatoms and bacteria from the environment and the development of an in vitro model system for reproducible laboratory studies followed by the investigation of the microbiome assembling on the diatom T. rotula using co-culture experiments. In Chapter 2 diatoms and bacteria were co-isolated from a spring bloom in the ...
Diatoms. Coloured scanning electron micrograph (SEM) of Epithemia and Navicula diatoms (pink). Diatoms are unicellular photosynthetic algae with mineralised cell walls (frustules). There are about 100,000 diatom species, forming an important part of the plankton at the base of the marine and freshwater food chains. These diatoms were found in the mountains of the Sierra Nevada of southern Spain, in the pool of a waterfall, at an altitude 2000 metres. Magnification: x1440 when printed at 10 centimetres across. - Stock Image C003/6657
Read The morphology and development in laboratory culture of the diatoms Skeletonema grethae Zingone et Sarno, 2005 and S. japonicum Zingone et Sarno, 2005, which are new to the seas of Russia, Russian Journal of Marine Biology on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.
Despite many advances in research on photosynthetic carbon fixation in marine diatoms, the biophysical and biochemical mechanisms of extracellular polysaccharide production remain significant challenges to be resolved at the molecular scale in order to proceed toward an understanding of their functions at the cellular level, as well as their interactions and fate in the ocean. This review covers studies of diatom extracellular polysaccharides using atomic force microscopy (AFM) imaging and the quantification of physical forces. Following a brief summary of the basic principle of the AFM experiment and the first AFM studies of diatom extracellular polymeric substance (EPS), we focus on the detection of supramolecular structures in polysaccharide systems produced by marine diatoms. Extracellular polysaccharide fibrils, attached to the diatom cell wall or released into the surrounding seawater, form distinct supramolecular assemblies best described as gel networks. AFM makes characterization of the diatom
Fucoxanthin, one of the main marine carotenoids, is abundant in macro- and microalgae. Here, fucoxanthin was isolated and structurally identified as the major carotenoid in the diatom Phaeodactylum tricornutum through chromatographic and spectroscopic methods, such as liquid chromatography–positive-ion atmospheric pressure chemical ionization/mass spectroscopy and nuclear magnetic resonance. This pigment was quantified by reverse-phase high-performance liquid chromatography, and a number of extraction procedures were assessed to investigate the effect of solvent type, extraction time, temperature, and extraction method (maceration, ultrasound-assisted extraction, Soxhlet extraction, and pressurized liquid extraction). Among the investigated solvents, ethanol provided the best fucoxanthin extraction yield (15.71 mg/g freeze-dried sample weight). Fucoxanthin content in the extracts produced by the different methods was quite constant (15.42–16.51 mg/g freeze-dried sample weight) but ...
Different sources of nitrogen pose diverse effects to algal community, but the mechanism of inhibitory effects of nitrogen sources on freshwater diatoms is not fully understood. The purpose of this study was to compare biomass, photosynthetic activity, and morphological structure of three common freshwater diatoms (Cyclotella meneghiniana, Nitzschia sp., and Gomphonema parvulum) under different nitrogen sources (NO3 − or NH4 +). The sorption characteristic of each diatom was investigated, and chlorophyll a (Chl-a) content and oxygen evolution rate were analyzed to investigate stress of different nitrogen sources on each diatom in the batch experiments. Ammonium lowered the growth rate of C. meneghiniana and Nitzschia sp. when it was supplied in addition to growth-saturating nitrate concentrations, suggesting a combined effect of inhibition of nitrate uptake and direct ammonium stress. Oxygen evolution rate of Nitzschia sp. showed that the direct ammonium stress on the photosynthetic activity can be
According to the shape of the valves, the arrangement of the valve striae and the type of sexual reproduction, the diatoms are divided in centric diatoms and pennate diatoms. The two valves or only one of most of the pennate diatoms have a longitudinal slit, the raphe, interrupted in the middle by a bridge of silica. This raphe is either simple or as a complex structure, the raphe-canal, the interior of which is divided by bridges of silica named the fibulae ...
Triacylglycerols (TAGs) from microalgae have the potential to be used for biodiesel, but several technical and economic hurdles have to be overcome. A major challenge is efficient extraction of intracellular TAGs from algae. Here we investigate the use of enzymes to deconstruct algal cell walls/membranes. We describe a rapid and simple assay that can assess the efficacy of different enzyme treatments on TAG-containing algae. By this means crude papain and bromelain were found to be effective in releasing TAGs from the diatom Phaeodactylum tricornutum, most likely because of their cysteine protease activity. Pre-treating algal biomass with crude papain enabled complete extraction of TAGs using heptane/isopropyl alcohol. Heptane as a single solvent was also effective, although complete recovery of TAG was not obtained. Economic implications of these findings are discussed, with the aim to reduce the complexity of, and energy needed in, TAG extraction.. ...
Herbicides pose a potential threat to aquatic ecosystems, especially to phototrophic organisms such as benthic diatoms. Benthic diatoms may be a valuable indicator of the toxic impacts of herbicides in aquatic systems. However, this requires information on the herbicide sensitivity of a wide range of freshwater benthic diatom taxa. Unfortunately this information is only available for a limited number of species as current methods of developing new algae toxicity tests on individual taxa are lengthy and costly. To address this issue, we developed a new rapid toxicity test method to test natural benthic communities, from which the relative herbicide sensitivity of many individual taxa can be derived. This involved the collection of natural benthic communities from rocks in situ, which were placed directly into laboratory toxicity tests. Sensitivity data for several diatom genera in a 48 hour exposure toxicity test were produced, without the need for cultures or multiple site visits. After exposure ...
2013 December Shilpas, Ashishs and Xiaofengs (equal contributors) paper on the role of reflux in metabolic flux analysis is accepted for publication in Molecular BioSystems. 2013 November Yuting successfully defends her PhD thesis. Congrats! 2013 November Andrews and Yutings (equal contributors) paper on investigation of glucose-metabolizing pathways in the marine diatom Phaeodactylum tricornutum is accepted for publication in Microbial Cell Factories. Congrats! 2013 November Ashishs paper on computational gene regulatory network analysis in Arabidopsis is accepted for publication in BMC Systems Biology. Congrats! This article is highly accessed as of 30 November 2013. 2013 August Ganeshs book on plant metabolism methods to appear by the end of 2013. 2013 June Ashishs and Matts paper is accepted in Frontiers in Microbiology. Congrats! 2012 November Shilpa successfully defends her PhD thesis. Congrats! 2012 October Shilpas paper is accepted in Molecular BioSystems. 2012 August Dr. ...
A new regional dataset comprising 425 intertidal diatom taxa from 175 samples from 11 ecologically diverse Oregon and Washington estuaries illustrates the importance of compiling a large modern dataset from a range of sites. Cluster analyses and detrended correspondence analysis of the diatom assemblages identify distinct vertical zones within supratidal, intertidal and subtidal environments at six of the 11 study sites, but the abundance of some of the most common species varies widely among and within sites. Canonical correspondence analysis of the regional dataset shows relationships between diatom species and tidal exposure, salinity and substratum (grain size and organic content). Correspondence analyses of local datasets show higher values of explained variation than the analysis of the combined regional dataset. Our results emphasize that studies of the autecology of diatom species require many samples from a range of modern environments to adequately characterize species-environment ...
Lakes, rivers, estuaries, backwaters and even oceans are becoming more and more polluted due to influx of sewage and fertilizer runoff. Most of the fresh water in the world is held in lakes and reservoirs. Solution is a simple and effective to treat sewage and eutrophied water bodies. It contains micronutrients required by Diatom Algae in nano size (5 to 20 nano meters), contains Si, Fe, Mn, Ca, Mg, Zn, Cu, B, S, Mo, etc.,. How does it works? - It causes a bloom of Diatom Algae. Diatom Algae are aquatic plants that absorb carbon dioxide and release oxygen during photosynthesis. Higher oxygen levels in water enable aerobic bacteria to grow and these breakdown organics in the water. Thus product and Diatoms are a substitute for electric powered Aerators used in pond and lake restoration.. Why Diatom Algae? - Diatoms have a silica body, unlike other algae such as Green Algae and Blue Green Algae which have cellulose bodies. Diatoms are consumed by zooplankton and these by fishes. Thus the organic ...
Diatoms are unicellular algae that exhibit exquisite silica cell walls, frustules, made of amorphous silica. Research has shown that diatoms are capable of controlled precipitation of silica during cell division within a specialized membrane called the silica deposition vesicle (SDV). The precipitated silica forms the new shell for the daughter cell. It has been postulated that the diatom SDV contains an emulsion of organic macromolecules arranged in a regular pattern which serve as a template onto which silica is precipitated. Our goal of this project is to use a specially designed emulsification microreaction chamber to gain insight on biosilica formation in vitro at room temperature and near-neutral pH using micro/nanoemulsion templating with synthetic catalyst and diatom-derived silaffins to create micro- and nanoporous silica ...
Porous silica is an attractive biomaterial in many applications, including drug-delivery systems, bone-graft fillers and medical devices. The issue with porous silica biomaterials is the rate at which they resorb and the significant role played by interfacial chemistry on the host response in vivo. This paper explores the potential of diatom-biosilica as a model tool to assist in the task of mapping and quantifying the role of surface topography and chemical cues on cell fate. Diatoms are unicellular microalgae whose cell walls are composed of, amorphous nanopatterned biosilica that cannot be replicated synthetically. Their unique nanotopography has the potential to improve understanding of interface reactions between materials and cells. This study used Cyclotella meneghiniana as a test subject to assess cytotoxicity and pro-inflammatory reactions to diatom-biosilica. The results suggest that diatom-biosilica is non-cytotoxic to J774.2 macrophage cells, and supports cell proliferation and growth. The
Despite a number of studies to examine phylogeny, using one or several genes, the relationships of diatoms to other groups are still unclear and there is still a huge gap in our understanding of how and when diatoms acquired their unusual morphology and life-cycle characteristics. The diatoms have often been treated as a separate phylum, reflecting their unique features. Pascher (1914, 1921) suggested that the diatoms have features in common with the Chrysophyceae and Xanthophyceae and therefore placed these classes and the Bacillariophyceae in the phylum Chrysophyta. Ultrastructural and molecular sequence data have confirmed the general thrust of Paschers idea, placing the diatoms unambiguously among the heterokont protists (stramenopiles) within the chromalveolates (Adl et al. 2005). In the past, it was sometimes suggested that diatoms evolved well before their appearance in the fossil record and that the early phases in diatom evolution were lost long ago through diagenesis of diatomites ...
Marine microfossils, including protistan autotrophs and heterotrophs, have traditionally been thought to be one of the broadly construed taxonomic groups most affected by the end-Cretaceous extinction. Does harry styles have a private Instagram account? They are found in both freshwater and saltwater. diatoms are autotrophic or heterotrophic? The term photoautótrofos is derived from the Greek phototroph that meansto feed on light, among these we find plants and seaweed. Food is stored as oil droplets, and the golden-brown pigment fucoxanthin masks the chlorophyll and carotenoid pigments that are also present. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. Many cells live cooperatively together as a sphere: How do volvox get their food? 48 Forever. A desmid is a single-celled green algae, which can be found only in freshwaters. Is Red Algae autotrophic of heterotropic? Diatoms are among the most important and prolific ...
Diatoms are a major group of algae and are among the most common types of phytoplankton. Diatoms are unicellular organism, although they can form...
Diatoms are a diverse group of eukaryotic microalgae responsible for as much as 25% of global and 50% of oceanic annual primary production (1). Lipids, hydrophobic or amphipathic biological molecules (2, 3), make up 25 to 45% of the total dry weight of diatoms (4), representing a major pool of organic carbon. In the equatorial Pacific Ocean, for example, lipids account for 23% of the organic, total planktonic carbon (5).. Lipid biosynthesis involves a network of reactions that, through the exchange of polar headgroups and fatty acids, generate a rich variety of lipids (3, 6). Remodeling of a cells lipidome (the entirety of its cellular lipids) in response to environmental conditions is common in unicellular organisms (7, 8). One such remodeling mechanism utilizes the replacement of membrane glycerophospholipids with nonphosphorus glycerolipid counterparts when an organism is subjected to phosphorus (P) stress or starvation (7-10). This response allows a phytoplankter to reduce its P demands in ...
Enzymes involved in CO2-concentrating mechanisms (CCMs), such as carbonic anhydrases and bicarbonate transporters, do not show a specific transcript level trend in P. tricornutum and T. pseudonana [26,28]. Calvin cycle-related genes show reduced expression in P-limited P. tricornutum cultures, but are unregulated in T. pseudonana. This could be related to reduced photosynthetic capacity under P limitation in P. tricornutum, which also has been shown for other diatom species [31,39-42]. Assuming that the P-limiting conditions were similar in both experiments, T. pseudonana might be less sensitive to P limitation. Whereas P. tricornutum stopped dividing after 48 h of P limitation, T. pseudonana grew for 124 h before cell division halted [26,28]. Triose phosphates produced by the Calvin cycle enter the plastidic glycolysis or are exported to the cytosol by triose phosphate transporters (TPTs); the specificities of diatom TPTs have not yet been characterized [43]. Glyceraldehyde-3-phosphate as well ...
Light is an essential source of energy for life on Earth and is one of the most important signals that organisms use to obtain information from the surrounding environment, on land and in the oceans. Prominent marine microalgae, such as diatoms, display a suite of sophisticated responses (physiological, biochemical, and behavioural) to optimize their photosynthesis and growth under changing light conditions. However, the molecular mechanisms controlling diatom responses to light are still largely unknown. Recent progress in marine diatom genomics and genetics, combined with well-established (eco) physiological and biophysical approaches, now offers novel opportunities to address these issues. This review provides a description of the molecular components identified in diatom genomes that are involved in light perception and acclimation mechanisms. How the initial functional characterizations of specific light regulators provide the basis to investigate the conservation or diversification of ...
Abstract Viruses infecting diatoms might be primary agents in shaping diatom population dynamics. Diatom viruses were discovered as recently as a decade ago. Since then, data on diatom viruses have rapidly accumulated. At least 18 diatom viruses have been isolated and characterized. They are broadly divided into 2 groups based on genome conformation: ssDNA (Bacilladnavirus) or ssRNA (Bacillarnavirus) viruses. They are icosahedral ...
A diatom quality index to assess diatom community impairment in the nearshore wetlands of the Laurentian Great Lakes was developed from a diatom-based total phosphorus (TP) weighted average inference model. The index is calculated with a weighted average equation using species optima standardized to a 1-10 scale and species tolerance standardized to a 1-3 scale. Multiple regression analysis revealed a moderate fit (R2 = 0.63) between site scores of the selected index and GIS derived watershed characteristics (agriculture, soils, and industrial facilities). These index scores more closely fit watershed characteristics than the diatom inferred TP (R2 = 0.59). In a regression tree analysis, soil permeability separated higher index scores from lower scores identifying this variable as an important interaction factor in the analysis. The diatom quality index can be a powerful tool for analyzing habitat quality in the Great Lakes and can communicate the link between quantifiable diatom assemblage ...
Changes in iron (Fe) bioavailability influence diatom physiology and community composition, and thus have a profound impact on primary productivity and ecosystem dynamics. Iron limitation of diatom growth rates has been demonstrated in both oceanic and coastal waters of the Northeast Pacific Ocean and is predicted to become more pervasive in future oceans. However, it is unclear how the strategies utilized by phytoplankton to cope with low Fe bioavailability and resupply differ across these ocean provinces. We investigated the response of diatom communities to variable Fe conditions through incubation experiments performed in the Fe mosaic of the California Upwelling Zone and along a natural Fe gradient in the Northeast Pacific Ocean. Through coupling gene expression of two dominant diatom taxa (Pseudo-nitzschia and Thalassiosira) with biological rate process measurements, we provide an in-depth examination of the physiological and molecular responses associated with varying Fe status. Following Fe
Evans, K. M. , Bates, S. S. , Medlin, L. and Hayes, P. K. (2004): . Microsatellite marker development and genetic variation in the toxic marine diatom Pseudo-nitzschia multiseries (Bacillariophyceae). , Journal of Phychology ...
Diatom Cultures. The diatom Thalassiosira pseudonana was selected as the study organism as it has a well-characterized physiology, genome, and proteome [11, 25-27]. T. pseudonana clone 3H (CCMP1335, mean diameter: 4 µm) was obtained from the Provasoli-Guillard Center for Culture of Marine Phytoplankton (West Boothbay Harbor, ME, USA). Cells were grown axenically using semi-continuous batch culturing with a modified version of f/2 made in 0.2-µm filtered and microwave-sterilized Sargasso seawater [28]. Fe was added separately to achieve the desired concentrations. Biological duplicate cultures grown under replete conditions received 400 nM Fe. The inoculum for the biological duplicate Fe-limited treatment came from an exponentially growing replete culture that was diluted (1:10) in media without added Fe. Cultures were grown in 2-L acid-cleaned polycarbonate flasks. All cultures were maintained at 13°C, at a continuous light intensity of 150 μmol quanta m- 2 s-1, and provided with cool-white ...
The diversity of Pseudo-nitzschia (Bacillariophyceae) and accumulation of the neurotoxin domoic acid (DA) in two types of shellfish; tuberculate cockles (Acanthocardia tuberculata) and sweet clams (Challista chione) was explored in Mdiq Bay,Morocco during 2007. The highest abundances of Pseudo-nitzschia were found during the period from March to October, with peaks occurring in May and September. Toxin analysis showed an accumulation of domoic acid in shellfish sampled during spring and autumn. The maximum toxin concentration was 4.9 mg DAg-1 of the whole tissue recorded in sweet clam during spring. Using transmission electron microscopy, thirteen Pseudo-nitzschia species were identified, eight of which are known as producers of domoic acid: P. multistriata, P. cuspidata, P. galaxiae, P. multiseries, P. pseudodelicatissima, P. pungens var. aveirensis, P. calliantha and P. fraudulenta. The five non- toxic species observed were P. subpacifica, P. arenysensis, P. dolorosa, P. subfraudulenta, and ...
Biogeochemical cycles and sedimentary records in lakes are related to climate controls on hydrology and catchment processes. Changes in the isotopic composition of the diatom frustules (δ18Odiatom and δ13Cdiatom) in lacustrine sediments can be used to reconstruct palaeoclimatic and palaeoenvironmental changes. The Lago Chungará (Andean Altiplano, 18°15′S, 69°10′W, 4520 masl) diatomaceous laminated sediments are made up of white and green multiannual rhythmites. White laminae were formed during short-term diatom super-blooms, and are composed almost exclusively of large-sized Cyclostephanos andinus. These diatoms bloom during mixing events when recycled nutrients from the bottom waters are brought to the surface and/or when nutrients are introduced from the catchment during periods of strong runoff. Conversely, the green laminae are thought to have been deposited over several years and are composed of a mixture of diatoms (mainly smaller valves of C. andinus and Discostella stelligera) ...
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A selective and label-free biosensor for detection of the explosive compound 2,4,6-trinitrotoluene (TNT) in aqueous solution was developed based on the principle of photoluminescence quenching of upon immunocomplex formation with antibody-functionalized diatom frustule biosilica. The diatom frustule is an intricately nanostructured, highly porous biogenic silica material derived from the shells of microscopic algae called diatoms. This material emits strong visible blue photoluminescence (PL) upon UV excitation. PL-active frustule biosilica was isolated from cultured cells of the marine diatom Pinnularia sp. and functionalized with a single chain variable fragment (scFv) derived from an anti-TNT monoclonal antibody. When TNT was bound to the anti-TNT scFv-functionalized diatom frustule biosilica, the PL emission from the biosilica was partially quenched due to the electrophilic nature of the nitro (-NO₂) groups on the TNT molecule. The dose-response curve for immunocomplex formation of TNT on ...
Diatoms are among the dominant phytoplankters in the worlds oceans, and their external silica investments, resembling artificial photonic crystals, are expected to play an active role in light manipulation. Digital holography allowed studying the interaction with light of Coscinodiscus wailesii cell wall reconstructing the light confinement inside the cell cytoplasm, condition that is hardly accessible via standard microscopy. The full characterization of the propagated beam, in terms of quantitative phase and intensity, removed a long‐standing ambiguity about the origin of the light confinement. The data were discussed in the light of living cell behavior in response to their environment. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim ...
About half the carbon fixed by phytoplankton in the ocean is taken up and metabolized by marine bacteria, a transfer that is mediated through the seawater dissolved organic carbon (DOC) pool. The chemical complexity of marine DOC, along with a poor understanding of which compounds form the basis of trophic interactions between bacteria and phytoplankton, have impeded efforts to identify key currencies of this carbon cycle link. Here, we used transcriptional patterns in a bacterial-diatom model system based on vitamin B12 auxotrophy as a sensitive assay for metabolite exchange between marine plankton. The most highly up-regulated genes (up to 374-fold) by a marine Roseobacter clade bacterium when cocultured with the diatom Thalassiosira pseudonana were those encoding the transport and catabolism of 2,3- dihydroxypropane-1-sulfonate (DHPS). This compound has no currently recognized role in the marine microbial food web. As the genes for DHPS catabolism have limited distribution among bacterial ...
ABSTRACT: Larval settlement of the polychaete Hydroides elegans Haswell, 1883 is mediated by marine biofilms; complex agglomerates of bacteria, diatoms, fungi and protozoa enmeshed in a matrix of extracellular polymers (EPS). In our previous investigations, benthic diatoms were demonstrated to be potent mediators of larval settlement in H. elegans. The putative diatom-derived settlement cues were heat-stable components in close association with the diatom surface. For an in-depth investigation of the chemical nature of diatom-derived larval settlement cues, the EPS of the inductive (Achnanthes sp., Nitzschia constricta) and non-inductive (Amphora tenerrima, Nitzschia frustulum) diatoms were bioassayed for their effect on larval settlement. When EPS fractions larger than 100 kDa were immobilized in stable hydrogels to mimic their association to a solid substratum, they evoked an effect on larval settlement similar to that of the respective monospecies diatom films. The crude exopolymer samples ...
Silicon is an essential element for growth in diatoms. It is, for example, used to build the silicieous frustule surrounding the diatom cell wall. Silicon starvation studies have also inferred that silicon is essential in the vital metabolic processes of DNA and chlorophyll synthesis. The mechanism of essentiality is, however, uncertain. In laboratory cultures at circumneutral pH and using a non-growth-limiting, but environmentally realistic, concentration of the essential nutrient phosphorus, we have demonstrated aluminium toxicity in the freshwater diatom Navicula pelliculosa and the amelioration of this toxicity with silicon, present in aqueous solution as silicic acid. The mechanism of aluminium toxicity was an aluminium-induced reduction in the biologically available phosphorus fraction and silicic acid protected against this effect by preferentially binding aluminium in competition with phosphorus. Silicon stimulated growth in the presence of aluminium was also demonstrated in the ...
Estuaries are dynamic on many spatial and temporal scales. Distinguishing effects of unpredictable events from cyclical patterns can be challenging but important to predict the influence of press and pulse drivers in the face of climate change. Diatom assemblages respond rapidly to changing environmental conditions and characterize change on multiple time scales. The goals of this research were to 1) characterize diatom assemblages in the Charlotte Harbor watershed, their relationships with water quality parameters, and how they change in response to climate; and 2) use assemblages in sediment cores to interpret past climate changes and tropical cyclone activity. Diatom assemblages had strong relationships with salinity and nutrient concentrations, and a quantitative tool was developed to reconstruct past values of these parameters. Assemblages were stable between the wet and dry seasons, and were more similar to each other than to assemblages found following a tropical cyclone. Diatom assemblages
Roberts, Donna (1997) Reconstruction of lake-water salinity from fossil diatom assemblages in saline lakes of the Vestfold Hills, Antarctica. PhD thesis, University of Tasmania. ...
The new system is based on living diatoms, which are extremely small, single-celled algae, which already have shells with the nanostructure that is needed. They are allowed to settle on a transparent conductive glass surface, and then the living organic material is removed, leaving behind the tiny skeletons of the diatoms to form a template.. A biological agent is then used to precipitate soluble titanium into very tiny nanoparticles of titanium dioxide, creating a thin film that acts as the semiconductor for the dye-sensitized solar cell device. Steps that had been difficult to accomplish with conventional methods have been made easy through the use of these natural biological systems, using simple and inexpensive materials.. Conventional thin-film, photo-synthesizing dyes also take photons from sunlight and transfer it to titanium dioxide, creating electricity, Rorrer said. But in this system the photons bounce around more inside the pores of the diatom shell, making it more ...
Several types of filters are available for use in the microbiology laboratory. Inorganic filters are typified by the Seitz filter, which consists of a pad of porcelain or ground glass mounted in a filter flask.. Organic filters:. Organic filters are advantageous because the organic molecules of the filter attract organic components in microorganisms. They are given below:. 1) Berkefeld filter:. One example, The Berkefeld filter, utilizes as substance called diatomaceous earth. This material contains the remains of marine algae known as diatoms. Diatoms are unicellular algae that abound in oceans and provide important foundations for the worlds food chains. Their remains accumulate on the shoreline and are gathered for use in swimming pool aquarium filters, as well as for microbiological filters used in laboratories.. 2) Membrane Filter:. The membrane filter is at third type of filter that has received broad acceptance. It consists of a pad of organic compounds such as cellulose acetate ...
Several types of filters are available for use in the microbiology laboratory. Inorganic filters are typified by the Seitz filter, which consists of a pad of porcelain or ground glass mounted in a filter flask.. Organic filters:. Organic filters are advantageous because the organic molecules of the filter attract organic components in microorganisms. They are given below:. 1) Berkefeld filter:. One example, The Berkefeld filter, utilizes as substance called diatomaceous earth. This material contains the remains of marine algae known as diatoms. Diatoms are unicellular algae that abound in oceans and provide important foundations for the worlds food chains. Their remains accumulate on the shoreline and are gathered for use in swimming pool aquarium filters, as well as for microbiological filters used in laboratories.. 2) Membrane Filter:. The membrane filter is at third type of filter that has received broad acceptance. It consists of a pad of organic compounds such as cellulose acetate ...
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Biotin (vitamin H or vitamin B7) is the essential cofactor of biotin-dependent carboxylases, such as pyruvate carboxylase and acetyl-CoA carboxylase. Mammals cannot synthesize biotin, while in bacteria, fungi, and plants it is synthesized from pimelate thioester through different pathways. In E. coli and many organisms, pimelate thioester is derived from malonyl-ACP. The pathway starts with the methylation to malonyl-ACP methyl ester, followed by the fatty acid chain elongation cycle to form pimeloyl-ACP methyl ester, which is then demethylated to form pimeloyl-ACP [MD:M00572]. Pimeloyl-ACP is converted to biotin through the final four steps in the biotin bicyclic ring assembly, which are conserved among biotin-producing organisms [MD:M00123]. In B. subtilis, biotin is derived from pimeloyl-ACP formed by oxidative cleavage of long-chain acyl-ACPs [MD:M00573]. Some bacteria synthesize biotin from pimeloyl-CoA derived from pimelate [MD:M00577]. Biotin is covalently attached to biotin-dependent ...
A sediment core from the Arctic Revvatnet (Hornsund area, SW Spitsbergen, Svalbard) provided data on environmental changes over the last 3100 years. Diatom analysis showing the domination of planktoni
Diatoms are microscopic unicellular organisms that fix as much carbon annually as all terrestrial rainforests combined and, through nitrogen uptake and carbon drawdown, link global carbon and nitrogen cycles. As the most ...
Eleven whole-round core samples from Integrated Ocean Drilling Program Expedition 341 Sites U1417 and U1418 were tested for vertical permeability. Subsamples of each core were taken and analyzed for grain size, biogenic silica content, and clay mineralogy. Measured vertical permeability varied from 1.8 × 1018 to 1.5 × 1016 m2. With the exception of one sample from Site U1417, samples were dominated by clay-size (,4 μm) fractions with lesser silt-size (4-63 μm) and sand-size (,63 μm) fractions. Biogenic silica (SiO2) content ranged from 2 to 15 wt% at Site U1417 and was consistently ~2 wt% in samples from Site U1418. Clay mineral abundance exceeded that of quartz, feldspar, and calcite in all samples. Smectite content ranged from 3 to 38 wt% in Site U1417 samples and from 0 to 3 wt% in Site U1418 samples. 1 Screaton, E.J., Villaseñor, T., James, S.R., Meridth, L.N., Jaeger, J.M., and Kenney, W.F., 2017. Data report: permeability, grain size, biogenic silica, and clay minerals of Expedition ...
Sigma-Aldrich offers abstracts and full-text articles by [Peter J Lavrentyev, Gayantonia Franzè, James J Pierson, Diane K Stoecker].
Ryan Drum, PhD, AHG, has a BSc in Chemical Technology and a PhD in Botany (Phycology) from Iowa State University. While a NATO Scholar, he did postdoctoral studies on Cell Biology using the Electron Microscope and Microcine at the Universities of Bonn, Germany and Leeds, England . For 10 years Dr. Drum taught Botany and related subjects at Universities (UMASS/Amherst,UCLA, WWU). He studied Herbal Medicine with Ella Birzneck, founder of Dominion Herbal College in British Columbia for 12 years, and taught at their summer seminars for 25 years. He has been an adjunct faculty at Bastyr University since 1984, and he lectures at major herbal conferences and herbal schools. He specializes in Seaweed Therapies, Thyroid issues, and Mens Health. Dr. Drum is the author of over 30 scientific papers in peer-reviewed journals, the author of Electron Microscopy of Diatom Cells 1966, Springer Verlag, a 100-Plate Atlas, in print for 20 years, and a contributing author of two chapters in Planting the Future ...
Author: Smith, Sarah R. et al.; Genre: Journal Article; Published in Print: 2019; Title: Evolution and regulation of nitrogen flux through compartmentalized|br/| metabolic networks in a marine diatom
Deep-sea sediments cover ~70% of Earths surface and represent the largest interface between the biological and geological cycles of carbon. Diatoms and zooplankton faecal pellets naturally transport organic material from the upper ocean down to the deep seabed, but how these qualitatively different substrates affect the fate of carbon in this permanently cold environment remains unknown. We added equal quantities of 13C-labelled diatoms and faecal pellets to a cold water (−0.7 °C) sediment community retrieved from 1080 m in the Faroe-Shetland Channel, Northeast Atlantic, and quantified carbon mineralization and uptake by the resident bacteria and macrofauna over a 6-day period. High-quality, diatom-derived carbon was mineralized ,300% faster than that from low-quality faecal pellets, demonstrating that qualitative differences in organic matter drive major changes in the residence time of carbon at the deep seabed. Benthic bacteria dominated biological carbon processing in our experiments, ...
Author: Wichard, T. et al.; Genre: Journal Article; Published in Print: 2007; Keywords: Algae|br/|Fatty acids|br/|Food quality|br/|Lipids|br/|Metabolism|br/|Plankton|br/|Chemical defense|br/|Thalassiosira-rotula|br/|Skeletonema-costatum|br/|Alpha,beta,gamma,delta-unsaturated aldehydes|br/|Laboratory observations|br/|Calanus-helgolandicus|br/|Egg-production|br/|Acartia-tonsa|br/|Marine|br/|Biosynthesis|br/|Chemistry & Analysis in Current Contents(R)/Life Sciences; Title: Lipid and fatty acid composition of diatoms revisited: Rapid wound-activated change of food quality parameters influences herbivorous copepod reproductive success
Wold, Anette; Darnis, Gerald; Søreide, Janne E; Leu, Eva; Philippe, Benoit; Fortier, Louis; Poulin, Michel; Kattner, Gerhard; Graeve, Martin; Falk-Petersen, Stig (2011): Diatom abundance and fatty acid composition of ice algae and of Calanus glacialis in samples obtained in 2008 in the eastern Beaufort Sea. PANGAEA, https://doi.org/10.1594/PANGAEA.817986, Supplement to: Wold, A et al. (2011): Life strategy and diet of Calanus glacialis during the winter-spring transition in Amundsen Gulf, south-eastern Beaufort Sea. Polar Biology, 34(12), 1929-1946, https://doi.org/10.1007/s00300-011-1062-6
C. F. Tolman; Biogenesis of hydrocarbons by diatoms. Economic Geology ; 22 (5): 454-474. doi: https://doi.org/10.2113/gsecongeo.22.5.454. Download citation file:. ...
New interdisciplinary research has revealed the frontline role tiny algae could play in the battle against cancer, through the innovative use of nanotechnology.. The team of Professor Nico Voelcker at the University of South Australia and collaborators in Dresden, Germany, have genetically engineered diatom algae to become therapeutic nanoporous particles, which, when loaded with chemotherapeutic drugs can be used to destroy cancer cells in the human body, without harming healthy cells. Details of this research: Targeted drug delivery using genetically engineered diatom biosilica are being published in the latest edition of Nature Communications, this week and Professor Voelcker explains the potential benefits of this method to combat cancer.. By genetically engineering diatom algae - tiny, unicellular, photosynthesizing algae with a skeleton made of nanoporous silica, we are able to produce an antibody-binding protein on the surface of their shells, Prof Voelcker says.. Anti-cancer ...
Iron (Fe) is known to be mostly bound to organic ligands and to limit primary productivity in the Southern Ocean. It is thus important to investigate the bioavailability of organically bound Fe. In this study, we used four phytoplankton species of the Southern Ocean (Phaeocystis sp., Chaetoceros sp., Fragilariopsis kerguelensis and Thalassiosira antarctica Comber) to measure the influence of various organic ligands on Fe solubility and bioavailability. Short-term uptake Fe:C ratios were inversely related to the surface area to volume ratios of the phytoplankton. The ratio of extracellular to intracellular Fe is used to discuss the relative importance of diffusive supply and uptake to control Fe bioavailability. The effect of excess organic ligands on Fe bioavailability cannot be solely explained by their effect on Fe solubility. For most strains studied, the bioavailability of Fe can be enhanced relative to inorganic Fe in the presence of porphyrin, catecholate siderophore and saccharides ...
Here, we propose a novel strategy that combines a typical ultra high performance liquid chromatography (UHPLC), data-independent mass spectrometry (MS(E)) workflow with traveling wave ion mobility (TWIM) and UV detection, to improve the characterization of carotenoids and chlorophylls in complex biological matrices. UV detection selectively highlighted pigments absorbing at specific wavelengths, while TWIM coupled to MS was used to maximize the peak capacity. We applied this approach for the analysis of pigments in different microalgae samples, including Chlorella vulgaris, Dunaliella salina, and Phaeodactylum tricornutum. Using UHPLC-UV-MS(E) information (retention time, absorbance at 450 nm, and accurate masses of precursors and product ions), we tentatively identified 26 different pigments (carotenes, chlorophylls, and xanthophylls). By adding TWIM information (collision cross sections), we further resolved 5 isobaric pigments, not resolved by UHPLC-UV-MS(E) alone. The characterization of the ...
ABSTRACT: During summer 1994, the production regime at 2 sites located in the Indian sector of the Southern Ocean, one in the Permanent Open Ocean Zone (POOZ) at 52° S, and a second in the Seasonal Ice Zone (SIZ) at 63° S, was dominated by regeneration (0.3 , f-ratio , 0.4). Two time series, each of about 4 d, were performed over pre-determined time intervals of 4 h using a free-floating sediment trap set at 200 m at the 2 sites. Hourly variations of C, N, chlorophyll a (chl a) and its degradation products, taxon-specific pigments, lipid classes and dimethylsulfoniopropionate (DMSP) were measured simultaneously. Measurements in the water column were done during the sediment trap drifting. Fucoxanthin, a typical diatom pigment, was the major accessory pigment found in the trap material at the 2 stations, whereas, in the water column, the phytoplankton was dominated by flagellates in the POOZ and diatoms in the SIZ. This suggests selective grazing of diatoms by zooplankton and/or mass sinking of ...
Ghoshroy, S. and D.L. Robertson. 2015. The role of horizontal gene transfer in the evolution of nitrogen assimilating enzymes in the Prasinophytes. Journal of Molecular Evolution. 80(1):65-80. doi: 10.1007/s00239-014-9659-3. Epub 2014 Dec 11.. Boissonneault, K.R., B.M. Henningsen, S.S. Bates, D.L. Robertson, S. Milton, J. Pelletier, D.A. Hogan, and D.E. Housman. 2014. Gene expression studies for the analysis of domoic acid production in the marine diatom Pseudo-nitzschia multiseries. BMC Molecular Biology. 14:25 doi:10.1186/1471-2199-14-25. Ghoshroy S. and D.L. Robertson. 2012. Molecular evolution of glutamine synthetase II and III in the chromalveolates J. Phycol. 48:768-783. Ghoshroy, S. M. Binder, A. Tartar, and D.L. Robertson. 2010. Molecular evolution of glutamine synthetase II: Phylogenetic evidence of a non-endosymbiotic gene transfer event early in plant evolution BMC Evolutionary Biology, 10:198. doi:10.1186/1471-2148-10-198. Brown, K.L., K.I. Twing, and D.L. Robertson. 2009. Unraveling ...
Ghoshroy, S. and D.L. Robertson. 2015. The role of horizontal gene transfer in the evolution of nitrogen assimilating enzymes in the Prasinophytes. Journal of Molecular Evolution. 80(1):65-80. doi: 10.1007/s00239-014-9659-3. Epub 2014 Dec 11.. Boissonneault, K.R., B.M. Henningsen, S.S. Bates, D.L. Robertson, S. Milton, J. Pelletier, D.A. Hogan, and D.E. Housman. 2014. Gene expression studies for the analysis of domoic acid production in the marine diatom Pseudo-nitzschia multiseries. BMC Molecular Biology. 14:25 doi:10.1186/1471-2199-14-25. Ghoshroy S. and D.L. Robertson. 2012. Molecular evolution of glutamine synthetase II and III in the chromalveolates J. Phycol. 48:768-783. Ghoshroy, S. M. Binder, A. Tartar, and D.L. Robertson. 2010. Molecular evolution of glutamine synthetase II: Phylogenetic evidence of a non-endosymbiotic gene transfer event early in plant evolution BMC Evolutionary Biology, 10:198. doi:10.1186/1471-2148-10-198. Brown, K.L., K.I. Twing, and D.L. Robertson. 2009. Unraveling ...
The trimeric fucoxanthin-chlorophyll a/c protein (FCP) was purified from a Japanese brown alga, Cladosiphon okamuranus TOKIDA. Its pigment stoichiometry was determined to be chlorophyll (Chl) a:Chl c 1:Chl c 2:fucoxanthin = 4.6:1.1:1.0:5.5 by a combination of binary HPLC and 1H NMR spectroscopy. No violaxanthin found bound to the FCP. The ratio of Chl c/Chl a in this FCP is amongst the highest so far reported. ...
Craspedacusta sowerbyi reproduce asexually in the polyp form, via budding. They can form three different types of buds: polyps, frustules, or medusa buds. The polyp bud grows and develops while still attached to the original polyp. The frustule bud develops into a frustule; they are only able to travel a short distance before developing into a new polyp. The medusa bud detaches to form a free-living adult medusa, which reproduces sexually via fertilized eggs, which develop into planula larva. These larva settle onto underwater surfaces (plant roots, rocks, and tree roots) where they develop into polyps (Peard 2000).. Sexual reproduction is relatively rare in this form of jellyfish. Most populations are strictly male or female (Peard, 2000).. Scientists are still learning about the larvae and the conditions affecting the dispersal of this organism. Correlation studies have demonstrated a relationship between increased travel distance of the larvae and increased polyp feeding. It is believed that ...
Were very sorry but we do not have the time to answer such queries any longer.. Please do not write to us about Prorocentrum compressum (J.W.Bailey) Abé ex J.D.Dodge, supposedly a dinoflagellate, being a taxonomic synonym of Tryblionella compressa (J.W.Bailey) Poulin, supposedly a diatom. It is indeed an unusual case, but there was a difference of opinion as to the identity of the basionym Pyxidicula compressa J.W.Bailey, some authors treating it as a diatom and other as a dinoflagellate; the consensus now is that it is a diatom.. Please do not write to us about the change of spelling of Zostera noltii to Zostera noltei. The orthography Noltii was originally used by Hornemann to honour Ernst Ferdinand Nolte (1791-1875). Under the current International Code of Nomenclature the genitive singular honorific for a name ending in e is to add an i and not to delete the e and to add ii. There is no point in writing to me to complain about this. All four higher plant names honouring Nolte are ...
Were very sorry but we do not have the time to answer such queries any longer.. Please do not write to us about Prorocentrum compressum (J.W.Bailey) Abé ex J.D.Dodge, supposedly a dinoflagellate, being a taxonomic synonym of Tryblionella compressa (J.W.Bailey) Poulin, supposedly a diatom. It is indeed an unusual case, but there was a difference of opinion as to the identity of the basionym Pyxidicula compressa J.W.Bailey, some authors treating it as a diatom and other as a dinoflagellate; the consensus now is that it is a diatom.. Please do not write to us about the change of spelling of Zostera noltii to Zostera noltei. The orthography Noltii was originally used by Hornemann to honour Ernst Ferdinand Nolte (1791-1875). Under the current International Code of Nomenclature the genitive singular honorific for a name ending in e is to add an i and not to delete the e and to add ii. There is no point in writing to me to complain about this. All four higher plant names honouring Nolte are ...