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Sample records for algae flagellates rotifers

  1. Application of rotifer Brachionus plicatilis in detecting the toxicity of harmful algae

    NASA Astrophysics Data System (ADS)

    Yan, Tian; Wang, Yunfeng; Wang, Liping; Chen, Yang; Han, Gang; Zhou, Mingjiang

    2009-05-01

    The toxicity of seven major HAB (harmful algal bloom) species/strains, Prorocentrum donghaiense, Phaeocystis globosa, Prorocentrum micans, Alexandrium tamarense (AT-6, non-PSP producer), Alexandrium lusitanicum, Alexandrum tamarense (ATHK) and Heterosigma akashiwo were studied against rotifer Brachionus plicatilis under laboratory conditions. The results show that P. donghaiense, P. globosa, P. micans, A. tamarense (AT-6), or A. lusitanicum could maintain the individual survival and reproduction, as well as the population increase of the rotifer, but the individual reproduction would decrease when exposed to these five algae at higher densities for nine days; H. akashiwo could decrease the individual survival and reproduction, as well as population increase of the rotifer, which is similar to that of the starvation group, indicating that starvation might be its one lethal factor except for the algal toxins; A. tamarense (ATHK) has strong lethal effect on the rotifer with 48h LC50 at 800 cells/mL. The experiment on ingestion ability indicated by gut pigment change shows that P. donghaiense, P. globosa, P. micans, A. tamarense (AT-6) and A. lusitanicum can be taken by the rotifers as food, but A. tamarense (ATHK) or H. akashiwo can be ingested by the rotifers. The results indicate that all the indexes of individual survival and reproduction, population increase, gut pigment change of the rotifers are good and convenient to be used to reflect the toxicities of HAB species. Therefore, rotifer is suggested as one of the toxicity testing organisms in detecting the toxicity of harmful algae.

  2. Waltzing Volvox/: Orbiting Bound States of Flagellated Multicellular Algae

    NASA Astrophysics Data System (ADS)

    Drescher, K.; Leptos, K.; Pedley, T. J.; Goldstein, R. E.; Ishikawa, T.

    2008-11-01

    The spherical colonial alga Volvox swims by means of flagella on thousands of surface somatic cells. This geometry and its large size makes it a model organism for the fluid dynamics of multicellularity. Remarkably, when two nearby colonies swim close to a solid surface, they are attracted together and can form a stable bound state in which they continuously waltz around each other. A surface-mediated hydrodynamic attraction between colonies combined with the rotational motion of bottom-heavy Volvox are shown to explain the stability and dynamics of the bound state. This phenomenon is suggested to underlie observed clustering of colonies at surfaces.

  3. Flagellated algae protein evolution suggests the prevalence of lineage-specific rules governing evolutionary rates of eukaryotic proteins.

    PubMed

    Chang, Ting-Yan; Liao, Ben-Yang

    2013-01-01

    Understanding the general rules governing the rate of protein evolution is fundamental to evolutionary biology. However, attempts to address this issue in yeasts and mammals have revealed considerable differences in the relative importance of determinants for protein evolutionary rates. This phenomenon was previously explained by the fact that yeasts and mammals are different in many cellular and genomic properties. Flagellated algae species have several cellular and genomic characteristics that are intermediate between yeasts and mammals. Using partial correlation analyses on the evolution of 6,921 orthologous proteins from Chlamydomonas reinhardtii and Volvox carteri, we examined factors influencing evolutionary rates of proteins in flagellated algae. Previous studies have shown that mRNA abundance and gene compactness are strong determinants for protein evolutionary rates in yeasts and mammals, respectively. We show that both factors also influence algae protein evolution with mRNA abundance having a larger impact than gene compactness on the rates of algae protein evolution. More importantly, among all the factors examined, coding sequence (CDS) length has the strongest (positive) correlation with protein evolutionary rates. This correlation between CDS length and the rates of protein evolution is not due to alignment-related issues or domain density. These results suggest no simple and universal rules governing protein evolutionary rates across different eukaryotic lineages. Instead, gene properties influence the rate of protein evolution in a lineage-specific manner. PMID:23563973

  4. Toxicity of TiO(2) nanoparticles to cladocerans, algae, rotifers and plants - effects of size and crystalline structure.

    PubMed

    Clément, Laura; Hurel, Charlotte; Marmier, Nicolas

    2013-01-01

    With the rapid development of nanotechnology, there is an increasing risk of human and environmental exposure to nanotechnology-based materials. However, the data on the potential environmental effects of nanoparticles are scarce. The aim of this study is to assess the effect of particle size and crystal structure (anatase and rutile) of titanium dioxide on their toxicity. Thus, acute and chronic toxicity tests included a modified acute test (72 h) using daphnies and algae, rotifers and plants as model organisms. Gradient of toxicity varied with the tested biological organisms. Our results revealed that TiO(2) nanoparticles in anatase crystal structure are toxic in the entire set of tests conducted. However, at highconcentration, through their antimicrobial properties, they significantly promoted growth of roots. Because of its lipophilicity, the rutile crystalline structure of TiO(2) NPs form larger aggregates in aqueous medium; then they have less effect on biological organisms, and thus a lower toxicity than the anatase crystalline form of TiO(2). We also demonstrated that exposure duration, aggregation and concentrations are contributing factors in nanoparticles-mediated toxicity.

  5. Effects of rotifers, copepods and chironomid larvae on microbial communities in peatlands.

    PubMed

    Mieczan, Tomasz; Niedźwiecki, Michał; Tarkowska-Kukuryk, Monika

    2015-10-01

    Interactions between the microbial loop and the classical grazing food chain are essential to ecosystem ecology. The goal of the present study was to examine the impact of chironomid larvae, rotifers and copepods on the major components of the microbial food web (algae, bacteria, heterotrophic flagellates, testate amoebae and ciliates) in peatlands. Two enclosure experiments were carried out in a Sphagnum peatland. In the experiments we manipulated rotifers, copepods and macroinvertebrates, i.e. chironomid larvae (Psectrocladius sordidellus gr). During the experiments variation was observed in the abundance of potential predators. The beginning of the first experiment was distinguished by dominance of rotifers, but five days later copepods were dominant. In the second experiment copepods dominated. The results of this study are the first to suggest a substantial impact of chironomid larvae, rotifers and copepods on microorganism communities in peatland ecosystems. The impact is reflected by both a decrease in the abundance and biomass of testate amoebae and ciliates and a transformation of the size structure of bacteria. Heterotrophic flagellates (HNF) were not controlled by metazoans, but rather by testate amoebae and ciliates, as HNF were more abundant in the control treatment. PMID:26322497

  6. Effects of rotifers, copepods and chironomid larvae on microbial communities in peatlands.

    PubMed

    Mieczan, Tomasz; Niedźwiecki, Michał; Tarkowska-Kukuryk, Monika

    2015-10-01

    Interactions between the microbial loop and the classical grazing food chain are essential to ecosystem ecology. The goal of the present study was to examine the impact of chironomid larvae, rotifers and copepods on the major components of the microbial food web (algae, bacteria, heterotrophic flagellates, testate amoebae and ciliates) in peatlands. Two enclosure experiments were carried out in a Sphagnum peatland. In the experiments we manipulated rotifers, copepods and macroinvertebrates, i.e. chironomid larvae (Psectrocladius sordidellus gr). During the experiments variation was observed in the abundance of potential predators. The beginning of the first experiment was distinguished by dominance of rotifers, but five days later copepods were dominant. In the second experiment copepods dominated. The results of this study are the first to suggest a substantial impact of chironomid larvae, rotifers and copepods on microorganism communities in peatland ecosystems. The impact is reflected by both a decrease in the abundance and biomass of testate amoebae and ciliates and a transformation of the size structure of bacteria. Heterotrophic flagellates (HNF) were not controlled by metazoans, but rather by testate amoebae and ciliates, as HNF were more abundant in the control treatment.

  7. Tetraflagellochloris mauritanica gen. et sp. nov. (Chlorophyceae), a New Flagellated Alga from the Mauritanian Desert: Morphology, Ultrastructure, and Phylogenetic Framing.

    PubMed

    Barsanti, Laura; Frassanito, Anna Maria; Passarelli, Vincenzo; Evangelista, Valtere; Etebari, Maryam; Paccagnini, Eugenio; Lupetti, Pietro; Lenzi, Paola; Verni, Franco; Gualtieri, Paolo

    2013-02-01

    Morphological, ultrastructural, and molecular-sequence data were used to assess the phylogenetic position of a tetraflagellate green alga isolated from soil samples of a saline dry basin near F'derick, Mauritania. This alga can grow as individual cells or form non-coenobial colonies of up to 12 individuals. It has a parietal chloroplast with an embedded pyrenoid covered by a starch sheath and traversed by single parallel thylakoids, and an eyespot located in a parietal position opposite to the flagellar insertion. Lipid vacuoles are present in the cytoplasm. Microspectroscopy indicated the presence of chlorophylls a and b, with lutein as the major carotenoid in the chloroplast, while the eyespot spectrum has a shape typical of green-algal eyespots. The cell has four flagella, two of them long and two considerably shorter. Sequence data from the 18S rRNA gene and ITS2 were obtained and compared with published sequences for green algae. Results from morphological and ultrastructural examinations and sequence analysis support the placement of this alga in the Chlorophyceae, as Tetraflagellochloris mauritanica L. Barsanti et A. Barsanti, gen. et sp. nov. PMID:27008399

  8. Tetraflagellochloris mauritanica gen. et sp. nov. (Chlorophyceae), a New Flagellated Alga from the Mauritanian Desert: Morphology, Ultrastructure, and Phylogenetic Framing.

    PubMed

    Barsanti, Laura; Frassanito, Anna Maria; Passarelli, Vincenzo; Evangelista, Valtere; Etebari, Maryam; Paccagnini, Eugenio; Lupetti, Pietro; Lenzi, Paola; Verni, Franco; Gualtieri, Paolo

    2013-02-01

    Morphological, ultrastructural, and molecular-sequence data were used to assess the phylogenetic position of a tetraflagellate green alga isolated from soil samples of a saline dry basin near F'derick, Mauritania. This alga can grow as individual cells or form non-coenobial colonies of up to 12 individuals. It has a parietal chloroplast with an embedded pyrenoid covered by a starch sheath and traversed by single parallel thylakoids, and an eyespot located in a parietal position opposite to the flagellar insertion. Lipid vacuoles are present in the cytoplasm. Microspectroscopy indicated the presence of chlorophylls a and b, with lutein as the major carotenoid in the chloroplast, while the eyespot spectrum has a shape typical of green-algal eyespots. The cell has four flagella, two of them long and two considerably shorter. Sequence data from the 18S rRNA gene and ITS2 were obtained and compared with published sequences for green algae. Results from morphological and ultrastructural examinations and sequence analysis support the placement of this alga in the Chlorophyceae, as Tetraflagellochloris mauritanica L. Barsanti et A. Barsanti, gen. et sp. nov.

  9. Feeding and swimming of flagellates

    NASA Astrophysics Data System (ADS)

    Doelger, Julia; Nielsen, Lasse Tor; Kiorboe, Thomas; Bohr, Tomas; Andersen, Anders

    2015-11-01

    Hydrodynamics plays a dominant role for small planktonic flagellates and shapes their survival strategies. The high diversity of beat patterns and arrangements of appendages indicates different strategies balancing the trade-offs between the general goals, i.e., energy-efficient swimming, feeding, and predator avoidance. One type of flagellated algae that we observe, are haptophytes, which possess two flagella for flow creation and one so-called haptonema, a long, rigid structure fixed on the cell body, which is used for prey capture. We present videos and flow fields obtained using velocimetry methods around freely swimming haptophytes and other flagellates, which we compare to analytical results obtained from point force models. The observed and modelled flows are used to analyse how different morphologies and beat patterns relate to different feeding or swimming strategies, such as the capture mechanism in haptophytes. The Centre for Ocean Life is a VKR center of excellence supported by the Villum foundation.

  10. Ecotoxicology, ecophysiology, and mechanistic studies with rotifers.

    PubMed

    Dahms, Hans-U; Hagiwara, Atsushi; Lee, Jae-Seong

    2011-01-17

    Invertebrates play an increasing role in assessing the impacts of environmental contaminants in aquatic ecosystems. Substantial efforts were made to identify suitable and environmentally relevant models for toxicity testing. Rotifers have a number of promising characteristics which make them candidates worth considering in such efforts. They are small, simple in their organization, genetically homozygous, easy to cultivate. Rotifers are further widely distributed and ecologically important in freshwaters, in estuaries and coast, and also play an important role in the transportation of aquatic pollutants across the food web. In the last decades there has been a substantial increase of contributions on rotifers, particularly in areas of their ecology, geophylogeny, genomics and their behavioral, physiological, biochemical and molecular responses, following exposure to environmental chemicals and other stressors. Gene expression analysis enables ecotoxicologists to study molecular mechanisms of toxicity. Rotifers also appear as useful tools in the risk assessment of pharmaceuticals and their metabolites that find their way into aquatic ecosystems because their sensitivity to some of these substances is higher than that of cladocerans and algae. In respect to endocrine disruptors, rotifers seem to be particularly sensitive to androgenic and anti-androgenic substances, whereas copepods and cladocerans are typically more affected by estrogens and juvenile hormone-like compounds. Generally, a combination of whole-animal bioassays and gene expression studies allow an understanding of toxicological mechanisms. The purpose of this review is to demarcate the potential of using rotifers as important invertebrate aquatic model organisms for ecophysiology, ecotoxicology and environmental genomics. This review does not claim to find reasons for a superior use of rotifers in these fields. But the different phylogenetic allocation of rotifers in the Platyzoa (formerly

  11. Ecology of planktonic heterotrophic flagellates. A review.

    PubMed

    Mariottini, Gian Luigi; Pane, Luigi

    2003-01-01

    In aquatic environments heterotrophic flagellates are an important component within the microbial loop and the food web, owing to their involvement in the energy transfer and flux and as an intermediate link between bacteria and primary producers, and greater organisms, such as other protists and metazoan consumers. In the microbial loop heterotrophic flagellates highly contribute to fast biomass and nutrient recycling and to the production in aquatic environments. In fact, these protists consume efficiently viruses, bacteria, cyanobacteria and picophytoplankton, and are grazed mainly by other protists, rotifers and small crustaceans. In this paper the knowledge about these unicellular organisms is reviewed, taking into particular account their ecological relationships and trophic role within the plankton community of marine and freshwater environments.

  12. Rotifers as models for the biology of aging.

    PubMed

    Snell, Terry W

    2014-03-01

    It has been two decades since 1993 when research on the biology of rotifer aging was last reviewed by Enesco. Much has transpired during this time as rotifer biologists have adapted to the "omics" revolution and incorporated these techniques into the experimental analysis of rotifers. Rotifers are amenable to many of these approaches and getting adequate quantities of DNA, RNA, and protein from rotifers is not difficult. Analysis of rotifer genomes, transcriptomes, and proteomes is rapidly yielding candidate genes that likely regulate a variety of features of rotifer biology. Parallel developments in aging biology have recognized the limitations of standard animal models like worms and flies and that comparative aging research has essentially ignored a large fraction of animal phylogeny in the lophotrochozoans. As experimentally tractable members of this group, rotifers have attracted interest as models of aging. In this paper, I review advances over the past 20 years in the biology of aging in rotifers, with emphasis on the unique contributions of rotifer models for understanding aging. The majority of experimental work has manipulated rotifer diet and followed changes in survival and reproductive dynamics like mean lifespan, maximum lifespan, reproductive lifespan, and mortality rate doubling time. The main dietary manipulation has been some form of caloric restriction, withholding food for some period or feeding continuously at low levels. There have been comparative studies of several rotifer species, with some species responding to caloric restriction with life extension, but others not, at least under the tested food regimens. Other aspects of diet are less explored, like nutritional properties of different algae species and their capacity to extend rotifer lifespan. Several descriptive studies have reported many genes involved in rotifer aging by comparing gene expression in young and old individuals. Classes of genes up or down-regulated during aging have

  13. A Novel Basal Apparatus Protein of 90 kD (BAp90) from the Flagellate Green Alga Spermatozopsis similis is a Component of the Proximal Plates and Identifies the d-(dexter)Surface of the Basal Body.

    PubMed

    Geimer, S; Lechtreck, K F; Melkonian, M

    1998-05-01

    The flagellar basal apparatus consists of the basal bodies and associated fibrous structures, and represents the organizing center for the microtubular cytoskeleton in many flagellate protists. To identify novel proteins associated with the basal bodies, basal apparatuses from the flagellate green alga Spermatozopsis similis (Chlorophyceae) were isolated and purified. A polyclonal antibody raised against a 95kD protein band enriched in purified basal apparatuses was used to screen a cDNA library of S. similis which resulted in the isolation of a full length clone coding for a novel protein of 812 amino acids (85.3kD). Sequence analysis of this clone identified extended a-helical regions and predicted several coiled-coil forming domains interrupted by spacer segments of variable lengths. A polyclonal antibody (anti-BAp90) raised against the bacterially expressed protein recognized a 90kD band (BAp90) in SDS-PAGE of isolated basal apparatuses of S. similis. Immunogold labeling using anti-BAp90 decorated the proximal plates (two striated, triangular fibers which serve as spacers between the basal bodies in their proximal region) and parts of the d-fibers (df) which interconnect the basal bodies with the microtubular d-roots and the striated microtubule-associated fibers (SMAFs). Thus, the 90kD basal apparatus protein of S. similis represents a biochemical landmark for the lateral asymmetry of the basal body identifying its d-(dexter)surface. Cytoskeletal elements containing BAp90 or structurally related proteins may be involved in the organization and/or maintenance of the positional relationship between basal bodies and the cellular cytoskeleton, and hence cell polarity.

  14. Flagellate shiitake mushroom dermatitis.

    PubMed

    Luber, Adam J; Ackerman, Lindsay S

    2015-08-15

    An 84-year-old woman presented with 5 days of a pruritic skin eruption that formed arciform and linear patterns. She was diagnosed with flagellate shiitake mushroom dermatitis related to shiitake mushroom consumption the day prior symptom onset.

  15. Use of Copper to Selectively Inhibit Brachionus calyciflorus (Predator) Growth in Chlorella kessleri (Prey) Mass Cultures for Algae Biodiesel Production.

    PubMed

    Pradeep, Vishnupriya; Van Ginkel, Steven W; Park, Sichoon; Igou, Thomas; Yi, Christine; Fu, Hao; Johnston, Rachel; Snell, Terry; Chen, Yongsheng

    2015-08-31

    A single Brachionus rotifer can consume thousands of algae cells per hour causing an algae pond to crash within days of infection. Thus, there is a great need to reduce rotifers in order for algal biofuel production to become reality. Copper can selectively inhibit rotifers in algae ponds, thereby protecting the algae crop. Differential toxicity tests were conducted to compare the copper sensitivity of a model rotifer-B. calyciflorus and an alga, C. kessleri. The rotifer LC50 was <0.1 ppm while the alga was not affected up to 5 ppm Cu(II). The low pH of the rotifer stomach may make it more sensitive to copper. However, when these cultures were combined, a copper concentration of 1.5 ppm was needed to inhibit the rotifer as the alga bound the copper, decreasing its bioavailability. Copper (X ppm) had no effect on downstream fatty acid methyl ester extraction.

  16. Temporal and Spatial Dynamics of Planktonic Rotifers in the Elbe Estuary during Spring

    NASA Astrophysics Data System (ADS)

    Holst, H.; Zimmermann, H.; Kausch, H.; Koste, W.

    1998-09-01

    The spatial and temporal distribution of planktonic rotifers in the Elbe Estuary, Germany, was investigated at weekly intervals from March to July, 1995. Samples were taken at a fixed site in the Hahnöfer Nebenelbe, and the main channel was surveyed four times at eight stations from Hamburg to the upstream limits of the brackish-water zone. Abiotic and biotic parameters were determined and correlated with rotifer abundance to gain information about the forces that structure the rotifer community in this dynamic environment. A maximum density of 2048 ind. l -1was observed at the beginning of June. More than 70 rotifer species were identified during the whole period, but only a few of them appeared at significant densities. The predominant species were Keratella cochlearis, which accounted for over 32% of the total abundance, Keratella quadrata, Brachionus calyciflorusand species of the genera Synchaetaand Polyarthra. At the end of July Synchaeta bicornisappeared at the low density of 23 ind. l -1at the station farthest downstream. Except for this typical brackish-water species, all rotifers encountered belonged to freshwater taxa, which decreased in abundance rather rapidly toward the river mouth. From March to the middle of June, rotifers grazed predominantly on heterotrophic components of the microbial food-web, such as planktonic and aggregate-associated bacteria, detritus and heterotrophic flagellates. Toward the end of June, the chlorophyll aconcentration increased sharply, and a new rotifer community established itself, feeding mainly on autotrophic organisms in the Elbe Estuary.

  17. Algae.

    PubMed

    Raven, John A; Giordano, Mario

    2014-07-01

    Algae frequently get a bad press. Pond slime is a problem in garden pools, algal blooms can produce toxins that incapacitate or kill animals and humans and even the term seaweed is pejorative - a weed being a plant growing in what humans consider to be the wrong place. Positive aspects of algae are generally less newsworthy - they are the basis of marine food webs, supporting fisheries and charismatic marine megafauna from albatrosses to whales, as well as consuming carbon dioxide and producing oxygen. Here we consider what algae are, their diversity in terms of evolutionary origin, size, shape and life cycles, and their role in the natural environment and in human affairs.

  18. Algae.

    PubMed

    Raven, John A; Giordano, Mario

    2014-07-01

    Algae frequently get a bad press. Pond slime is a problem in garden pools, algal blooms can produce toxins that incapacitate or kill animals and humans and even the term seaweed is pejorative - a weed being a plant growing in what humans consider to be the wrong place. Positive aspects of algae are generally less newsworthy - they are the basis of marine food webs, supporting fisheries and charismatic marine megafauna from albatrosses to whales, as well as consuming carbon dioxide and producing oxygen. Here we consider what algae are, their diversity in terms of evolutionary origin, size, shape and life cycles, and their role in the natural environment and in human affairs. PMID:25004359

  19. Electrochemical monitoring systems of demembranated flagellate algal motility for ATP sensing.

    PubMed

    Shitanda, Isao; Tanaka, Koji; Hoshi, Yoshinao; Itagaki, Masayuki

    2014-02-21

    The ATP-induced behavior of the unicellular flagellate alga Chlamydomonas reinhardtii was recorded as changes in the redox currents for a coexisting redox marker. The ATP concentration was estimated using the presented compact electrochemical system, which is based on monitoring of the motility of the flagellates. PMID:24336166

  20. Lifespan extension of rotifers by treatment with red algal extracts

    PubMed Central

    Snare, David J.; Fields, Allison M.; Snell, Terry W.; Kubanek, Julia

    2013-01-01

    Aging results from an accumulation of damage to macromolecules inhibiting cellular replication, repair, and other necessary functions. Damage may be due to environmental stressors such as metal toxicity, oxidative stress caused by imperfections in electron transfer reactions, or other metabolic processes. In an effort to discover medical treatments that counteract this damage, we initiated a search for small molecule drugs from natural sources using life table experiments which, through their unbiased approach, present the opportunity to discover first-in-class molecules. We have identified marine red algae as a source of natural products that slow aging of the invertebrate rotifer Brachionus manjavacas. Rotifers are a promising model organism for life extension studies as they maintain a short, measurable lifespan while also having an extensive literature related to aging. Rotifer lifespan was increased 9–14% by exposure to three of a total of 200 screened red algal extracts. Bioassay guided fractionation led to semi-purified extracts composed primarily of lipids responsible for rotifer life extension. The life extending mixture from the red alga Acanthophora spicifera contained eicosanoic, octadecanoic, and hexadecanoic acids as well as several unidentified unsaturated fatty acids. The life extending effects of these small molecule mixtures are not a result of their direct antioxidant capacity; other unknown mechanisms of action are likely involved. An understanding of how these natural products interact with their molecular targets could lead to selective and effective treatments for slowing aging and reducing age related diseases. PMID:24120568

  1. Lifespan extension of rotifers by treatment with red algal extracts.

    PubMed

    Snare, David J; Fields, Allison M; Snell, Terry W; Kubanek, Julia

    2013-12-01

    Aging results from an accumulation of damage to macromolecules inhibiting cellular replication, repair, and other necessary functions. Damage may be due to environmental stressors such as metal toxicity, oxidative stress caused by imperfections in electron transfer reactions, or other metabolic processes. In an effort to discover medical treatments that counteract this damage, we initiated a search for small molecule drugs from natural sources using life table experiments which, through their unbiased approach, present the opportunity to discover first-in-class molecules. We have identified marine red algae as a source of natural products that slow aging of the invertebrate rotifer Brachionus manjavacas. Rotifers are a promising model organism for life extension studies as they maintain a short, measurable lifespan while also having an extensive literature related to aging. Rotifer lifespan was increased 9-14% by exposure to three of a total of 200 screened red algal extracts. Bioassay guided fractionation led to semi-purified extracts composed primarily of lipids responsible for rotifer life extension. The life extending mixture from the red alga Acanthophora spicifera contained eicosanoic, octadecanoic, and hexadecanoic acids as well as several unidentified unsaturated fatty acids. The life extending effects of these small molecule mixtures are not a result of their direct antioxidant capacity; other unknown mechanisms of action are likely involved. An understanding of how these natural products interact with their molecular targets could lead to selective and effective treatments for slowing aging and reducing age related diseases.

  2. Use of Copper to Selectively Inhibit Brachionus calyciflorus (Predator) Growth in Chlorella kessleri (Prey) Mass Cultures for Algae Biodiesel Production

    PubMed Central

    Pradeep, Vishnupriya; Van Ginkel, Steven W.; Park, Sichoon; Igou, Thomas; Yi, Christine; Fu, Hao; Johnston, Rachel; Snell, Terry; Chen, Yongsheng

    2015-01-01

    A single Brachionus rotifer can consume thousands of algae cells per hour causing an algae pond to crash within days of infection. Thus, there is a great need to reduce rotifers in order for algal biofuel production to become reality. Copper can selectively inhibit rotifers in algae ponds, thereby protecting the algae crop. Differential toxicity tests were conducted to compare the copper sensitivity of a model rotifer—B. calyciflorus and an alga, C. kessleri. The rotifer LC50 was <0.1 ppm while the alga was not affected up to 5 ppm Cu(II). The low pH of the rotifer stomach may make it more sensitive to copper. However, when these cultures were combined, a copper concentration of 1.5 ppm was needed to inhibit the rotifer as the alga bound the copper, decreasing its bioavailability. Copper (X ppm) had no effect on downstream fatty acid methyl ester extraction. PMID:26404247

  3. Flagellates and ciliates.

    PubMed

    Garcia, L S

    1999-09-01

    This article includes information on two human parasites, one protozoan flagellate, Giardia lamblia, and one ciliate, Balantidum coli. Both are transmitted through ingestion of food and water contaminated with fecal material. G. lamblia may be the most common intestinal protozoan found in humans throughout the world and causes a wide range of symptoms, all of which can be confused with other infectious and noninfectious causes. Although B. coli tends to be more restricted and associated with pigs as potential reservoir hosts, this organism can also cause mild to severe symptoms and can be found throughout the world. PMID:10549429

  4. [Population growth rate of the rotifer Brachionus rotundiformis (Rotifera: Brachionidae) in a two-stage chemostat].

    PubMed

    Cabrera, María I

    2008-09-01

    The population growth rate of the rotifer Brachionus rotundiformis (Rotifera: Brachionidae) in two-stage chemostat. The population growth rates of Brachionus rotundiformis were estimated in two-stage chemostat cultures. Chlorella sorokiniana was supplied continuously from a steady state culture growing with constant illumination on limiting nitrate. Rotifer growth in the second stage was limited by the rate of algal supply. The algal supply rate and rotifer population growth rate were determined by the second-stage dilution rate. The maximum population growth rate in the transient state of B. rotundiformis (1.96 day(-1)) was observed at 2.5 x 10(6) cel/ml of the algae whereas in the steady state the maximum population growth rate (1.09 day(-1)) was similar to the point Hopf's bifurcation predicted by Fussmann and was observed at 1 x 10(6) cel/ml of the algae. In the transient state, the rotifer's growth rate increased and the duplication time decreased at higher algal concentrations, until reaching a peak where the population growth rate begins to decrease. In the steady state, the opposite was true. The growth rates observed in this work are among the highest recorded for this rotifer in continuous cultures.

  5. Flagella number among Naegleria flagellates.

    PubMed

    John, D T; Cole, T B; John, R A

    1991-01-01

    Scanning electron microscopy was used to determine the number of flagella on the flagellates of Naegleria australiensis, N. fowleri, N. gruberi, and N. jadini. Although the majority of flagellates had 2 flagella, there was considerable variation among individual cells. The number of flagella per flagellate varied from 1-8, with 2.4 being the average number per cell. For the different species, the average number of flagella per cell ranged from 2.0 in N. jadini to 3.1 for N. australiensis. The greatest amount of variation occurred in N. australiensis, with only 43% of the cells having 2 flagella. By contrast, 92% of N. fowleri cells had 2 flagella. Naegleria jadini and N. gruberi were intermediate with 80% and 74% biflagellates, respectively.

  6. Rotifers ingest oocysts of Cryptosporidium parvum

    USGS Publications Warehouse

    Fayer, R.; Trout, J.M.; Walsh, E.; Cole, R.A.

    2000-01-01

    Six genera of rotifers including Philodina, Monostyla, Epiphanes, Euchlanis, Brachionus, and Asplanchna were exposed to oocysts of Cryptosporidium parvum cleaned of fecal debris. Unstained oocysts and those stained with fluorescein-conjugated monoclonal antibody were added to suspensions of viable rotifers and were examined by phase-contrast, differential interference contrast, and fluorescence microscopy. Rotifers of all six genera were observed ingesting oocysts. A maximum of 25 oocysts was observed in the stomachs of Euchlanis and Brachionus. Euchlanis and Epiphanes were observed excreting boluses containing up to eight oocysts. It was not determined whether rotifers digested or otherwise rendered oocysts nonviable.

  7. Sunshine bass fingerling production without rotifers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previously reported protocol for culture of sunshine bass larvae to fingerling size in tanks involved an initial feeding of rotifers for several days before the larvae are weaned to feed on Artemia nauplii. Maintaining rotifer cultures requires space, time, equipment, supplies, trained culturists a...

  8. Progress in understanding the phylogeny of flagellates.

    PubMed

    Sleigh, M A

    1995-01-01

    Heterotrophic free-living flagellates appear to provide the ancestry for all other eukaryote groups. Not only are the oldest surviving anaerobic eukaryotes flagellated protists, but also there appear to be survivors of a lineage of flagellate forms which could have been close to the sources of the main branches of eukaryote evolution. These 'stem' forms of flagellates developed more complex flagellation with anchoring fibres which became the main components of the cytoskeleton and supported the cytostome; by their phagotrophic activities these flagellates established symbiotic relationships, first with aerobic bacteria to form mitochondria, and later with various forms of prokaryotic and eukaryotic algal cells to form chloroplasts of a variety of types having different pigments, different structure and different food storage patterns. The specific patterns of flagellation, cytoskeleton, cytostome, secreted surface structures and cell aggregation into colonies enable groups of organisms to be recognised, whose most primitive survivors in almost all cases are heterotrophic flagellates. The current view of the phylogeny of eukaryotes suggests that heterotrophic flagellates have provided the origins of all major eukaryote groups, and that the phylogeny of these flagellates is the key to understanding the evolution of all eukaryotes. We anticipate that further rRNA analyses, supported by ultrastructural data, will confirm the central role played by these flagellates in eukaryote evolution.

  9. Gravitaxis and graviperception in flagellates.

    PubMed

    Hader, D-P; Lebert, M; Richter, P; Ntefidou, M

    2003-01-01

    There is strong evidence that gravitactic orientation in flagellates and ciliates is mediated by an active physiological gravireceptor rather than by passive alignment of the cells in the water column. In flagellates the threshold for graviorientation was found to be at 0.12 x g on a slow rotating centrifuge during the IML-2 mission on the Shuttle Columbia and a subsequent parabolic rocket flight (TEXUS). During the IML-2 mission no adaptation to microgravity was observed over the duration of the space flight, while gravitaxis was lost in a terrestrial closed environmental system over the period of almost two years. Sedimenting statoliths are not likely to be involved in graviperception because of the small size of the cells and their rotation around the longitudinal axis during forward locomotion. Instead the whole cytoplasmic content of the cell, being heavier than the surrounding aqueous medium (1.05 g/ml), exerts a pressure on the lower membrane. This force activates stretch-sensitive calcium specific ion channels which can be inhibited by the addition of gadolinium which therefore abolishes gravitaxis. The channels seem to mainly allow calcium ions to pass since gravitaxis is blocked by the addition of the calcium ionophore A23187 and by vanadate which blocks the Ca-ATPase in the cytoplasmic membrane. Recently, a gene for a mechanosensitive channel, originally sequenced for Saccharomyces, was identified in Euglena by PCR. The increase in intracellular free calcium during reorientation can be visualized by the fluorophore Calcium Crimson using laser excitation and image intensification. This result was confirmed during recent parabolic flights. The gated calcium changes the membrane potential across the membrane which may be the trigger for the reorientation of the flagellum. cAMP plays a role as a secondary messenger. Photosynthetic flagellates are suitable candidates for life support systems since they absorb CO2 and produce oxygen. Preliminary experiments

  10. New rotifer bioassays for aquatic toxicology. Final report, 16 November 1988-1 June 1991

    SciTech Connect

    Snell, T.W.

    1991-07-15

    A standard protocol was developed for assessing acute toxicity using the freshwater rotifer Brachionus calyciflorus. This protocol has several advantages over existing methods in that test animals are obtained by hatching dormant cysts, the test is highly reproducible, it has a low failure rate, and has good sensitivity to a variety of common pollutants. Cyst age up to 18 months had no effect on test animal response to toxicants. LC50s for copper and pentachlorophenol (PCP) were lower at 10 deg C and 30 deg C than at 20 deg C. B. calyciflorus LC50s were a good predictor of Daphnia magna and fathead minnow LC50s for eight common toxicants. A standard protocol using B. calyciflorus for estimating chronic toxicity of compounds in freshwater has been developed. The rotifer chronic test has several advantages over existing tests including: test animals are obtained from cysts, the test takes only 48 hours to complete, a simple algal food is sufficient for good rotifer reproduction and algae is obtained from a petri dish, the test has good sensitivity to a wide variety of common toxicants. Acute and chronic toxicity of trinitrotoluene has been characterized. The LC50 is 9.1 mg.L-1, the chronic value is 3.3 mg.L-1 and the acute/chronic ratio is 2.8, suggesting that TNT is only weakly chronically toxic. The effects of temperature on rotifer chronic toxicity over the 20 deg-30 deg C range were small.

  11. Flagellate dermatitis after consumption of Shiitake mushrooms

    PubMed Central

    Kreft, Burkhard; Marsch, Wolfgang Ch.

    2014-01-01

    Flagellate dermatitis occurs in patients who have eaten Shiitake mushrooms. We are reporting on a 55-year-old man, who developed whiplash-striped, severely itching efflorescences on the trunk 3 days after eating Lentinula edodes. Flagellate dermatitis is also known as a cutaneous side effect of bleomycin therapy. PMID:25097492

  12. Effects of diet on population development of the rotifer Brachionus plicatilis in culture

    NASA Astrophysics Data System (ADS)

    Planas, M.; Estévez, A.

    1989-06-01

    Experiments were conducted in order to observe the effect of five diets on the population development of the rotifer Brachionus plicatilis Müller under laboratory conditions. Diets were based on baker’s yeast ( Saccharomyces cerevisiae) and the algae Tetraselmis suecica and Isochrysis galbana, mixed, or as simple diets. Growth rates, fecundity and biometric parameters were studied for 15 days. The cultures were divided in a logarithmic phase and a harvesting phase. Rotifers fed on Tetraselmis, alone or mixed with yeast or Isochrysis, gave good performances with the best results in all the parameters studied. Average growth rates in all diets were similar during the exponential phase, with values ranging from 0.72 ( Tetraselmis and Tetraselmis + yeast) to 0.47 (yeast). During the harvesting phase there were high differences between diets, with rates highly reduced in the yeast-group (0.17) and good rates when Tetraselmis was ingested (0.65 0.51). This alga had a positive influence on the rotifers, increasing individual growth and fecundity.

  13. Graviperception and gravitaxis in flagellates

    NASA Astrophysics Data System (ADS)

    Häder, D.-P.; Richter, P.; Ntefidou, M.; Lebert, M.

    Unicellular flagellates perceive and react to the gravitational vector of the Earth. Previous hypotheses have suggested that the orientation is brought about by a passive physical mechanism such as buoyancy or hydrodynamic alignment. Recent results of experiments on parabolic rocket flights have revealed that in the photosynthetic Euglena only 10 % of the orientation can be explained by passive orientation while the remainder relies on an active physiological sensor and an internal sensory transduction chain. The cellular contents is heavier than the surrounding medium and consequently presses onto the lower membrane where it activates mechano-sensitive ion channels located at the front end under the trailing flagellum. These channels allow a gated influx of calcium (visualized by confocal microscopy) which depolarizes the internal electrical potential and eventually causes a course correction by the flagellar beating. Further elements in the transduction chain are cyclic AMP and related enzymes. Recent experiments during parabolic aircraft flights and on sounding rockets have confirmed this hypothesis and provided detailed insight into the biochemical sensory transduction chain. Currently the molecular mechanisms of graviperception are being studied.

  14. Biochemical diversification through foreign gene expression in bdelloid rotifers.

    PubMed

    Boschetti, Chiara; Carr, Adrian; Crisp, Alastair; Eyres, Isobel; Wang-Koh, Yuan; Lubzens, Esther; Barraclough, Timothy G; Micklem, Gos; Tunnacliffe, Alan

    2012-01-01

    Bdelloid rotifers are microinvertebrates with unique characteristics: they have survived tens of millions of years without sexual reproduction; they withstand extreme desiccation by undergoing anhydrobiosis; and they tolerate very high levels of ionizing radiation. Recent evidence suggests that subtelomeric regions of the bdelloid genome contain sequences originating from other organisms by horizontal gene transfer (HGT), of which some are known to be transcribed. However, the extent to which foreign gene expression plays a role in bdelloid physiology is unknown. We address this in the first large scale analysis of the transcriptome of the bdelloid Adineta ricciae: cDNA libraries from hydrated and desiccated bdelloids were subjected to massively parallel sequencing and assembled transcripts compared against the UniProtKB database by blastx to identify their putative products. Of ~29,000 matched transcripts, ~10% were inferred from blastx matches to be horizontally acquired, mainly from eubacteria but also from fungi, protists, and algae. After allowing for possible sources of error, the rate of HGT is at least 8%-9%, a level significantly higher than other invertebrates. We verified their foreign nature by phylogenetic analysis and by demonstrating linkage of foreign genes with metazoan genes in the bdelloid genome. Approximately 80% of horizontally acquired genes expressed in bdelloids code for enzymes, and these represent 39% of enzymes in identified pathways. Many enzymes encoded by foreign genes enhance biochemistry in bdelloids compared to other metazoans, for example, by potentiating toxin degradation or generation of antioxidants and key metabolites. They also supplement, and occasionally potentially replace, existing metazoan functions. Bdelloid rotifers therefore express horizontally acquired genes on a scale unprecedented in animals, and foreign genes make a profound contribution to their metabolism. This represents a potential mechanism for ancient

  15. Feeding and filtration rates of zooplankton (rotifers and cladocerans) fed toxic cyanobacterium (Microcystis aeruginosa).

    PubMed

    Pérez-Morales, Alfredo; Sarma, S S S; Nandini, S

    2014-11-01

    Microcystis aeruginosa is generally dominant in many Mexican freshwater ecosystems interacting with zooplankton species. Hence, feeding and filtration rates were quantified for three cladoceran (Daphnia pulex, Moina micrura and Ceriodaphnia dubia) and three rotifer species (Brachionus calyciflorus, Brachionus rubens and Plationus patulus) using sonicated M. aeruginosa alone or mixed with Scenedesmus acutus in different proportions (25, 50 and 75%, based on cell density), offering a combined initial density of 100,000 cells·ml(-1). All the three cladoceran species ingested M. aeruginosa (100-300 cells ind(-1) min(-1)) when fed exclusively with cyanobacterium. When green alga offered as exclusive diet, the number of cells ingested by the tested cladocerans varied from 80 to 400 cells ind(-1) min(-1). Compared to cladocerans, rotifers in general consumed much lower quantity (< 200 cells ind(-1) min(-1)) of M. aeruginosa and S. acutus. The filtration rate for Daphnia pulex was inversely related to the proportion of green alga in the diet. For other tested cladocerans, no such clear trend was evident. In mixed treatments containing M. aeruginosa, the filtration rate of Daphnia was highest (about 220 μl ind(-1) min(-1)) when the medium contained 75% of S. acutus. Among the rotifer species, P. patulus filtered highest volume (100 μl ind(-1) min(-1) from mixed diets containing higher proportions (50 or 75%) of M. aeruginosa. Thus, there were species-specific differences in the filtration and feeding rates of zooplankton when offered mixed diets of green algae and toxic cyanobacteria. These probably explain the coexistence of different zooplankton species in Microcystis-dominant waterbodies. PMID:25522500

  16. Putative bronchopulmonary flagellated protozoa in immunosuppressed patients.

    PubMed

    Kilimcioglu, Ali Ahmet; Havlucu, Yavuz; Girginkardesler, Nogay; Celik, Pınar; Yereli, Kor; Özbilgin, Ahmet

    2014-01-01

    Flagellated protozoa that cause bronchopulmonary symptoms in humans are commonly neglected. These protozoal forms which were presumed to be "flagellated protozoa" have been previously identified in immunosuppressed patients in a number of studies, but have not been certainly classified so far. Since no human cases of bronchopulmonary flagellated protozoa were reported from Turkey, we aimed to investigate these putative protozoa in immunosuppressed patients who are particularly at risk of infectious diseases. Bronchoalveolar lavage fluid samples of 110 immunosuppressed adult patients who were admitted to the Department of Chest Diseases, Hafsa Sultan Hospital of Celal Bayar University, Manisa, Turkey, were examined in terms of parasites by light microscopy. Flagellated protozoal forms were detected in nine (8.2%) of 110 cases. Metronidazole (500 mg b.i.d. for 30 days) was given to all positive cases and a second bronchoscopy was performed at the end of the treatment, which revealed no parasites. In conclusion, immunosuppressed patients with bronchopulmonary symptoms should attentively be examined with regard to flagellated protozoa which can easily be misidentified as epithelial cells.

  17. Renal flagellate infections in reptiles: 29 cases.

    PubMed

    Juan-Sallés, Caries; Garner, Michael M; Nordhausen, Robert W; Valls, Xavier; Gallego, Miguel; Soto, Sara

    2014-03-01

    Renal infection with flagellated protozoa was retrospectively evaluated in 29 reptiles, including 12 turtles, 7 tortoises, and 6 chameleons; overall, 20 species of reptiles were represented. Most cases presented with nonspecific clinical signs or a combination of several concurrent diseases. Nineteen of 29 reptiles had tubulointerstitial nephritis associated with flagellates, and this lesion was considered contributory to death in 15 cases, although concurrent diseases were frequent. Infection was invasive into the renal interstitium in three reptiles due to tubular rupture and in one chameleon also spread to adjacent tissues, coelomic cavity, and blood vessels due to renal rupture. Cytologic or ultrastructural evaluation of trophozoites in two cases was consistent with diplomonad flagellates. Renal disease was often complicated with soft-tissue mineralization and/or gout. Gastrointestinal and cloacal infection with flagellates and inflammation were frequent in reptiles in which the digestive tract was available for histopathologic examination, and this supports the possibility of infections ascending the urinary tract from the cloaca. Renal disease associated with flagellate protozoa is rare in vertebrates but appears to be relevant in reptiles, particularly chelonians and chameleons.

  18. Evidence for meiotic sex in bdelloid rotifers.

    PubMed

    Signorovitch, Ana; Hur, Jae; Gladyshev, Eugene; Meselson, Matthew

    2016-08-22

    In their study of genetic exchange in the bdelloid rotifer Adineta vaga, Debortoli et al. [1] conclude that the patchwork pattern of allele sharing among three individuals in the genomic regions they examined is "…unlikely to arise in cases of PTH (Oenothera-like) meiosis since haplotypes are transferred as entire blocks…" and therefore that "Genetic exchange among bdelloid rotifers is more likely due to horizontal gene transfer than to meiotic sex." This assumes without justification that horizontal gene transfer (HGT) in bdelloids precludes the sexual transmission of entire haplotypes, for which we have reported evidence in the bdelloid Macrotrachela quadricornifera[2]. And it does not consider the contribution to such a patchwork pattern that would result from conversion and subsequent outcrossing, even in Oenothera-like systems. PMID:27554650

  19. Evidence for degenerate tetraploidy in bdelloid rotifers.

    PubMed

    Mark Welch, David B; Mark Welch, Jessica L; Meselson, Matthew

    2008-04-01

    Rotifers of class Bdelloidea have evolved for millions of years apparently without sexual reproduction. We have sequenced 45- to 70-kb regions surrounding the four copies of the hsp82 gene of the bdelloid rotifer Philodina roseola, each of which is on a separate chromosome. The four regions comprise two colinear gene-rich pairs with gene content, order, and orientation conserved within each pair. Only a minority of genes are common to both pairs, also in the same orientation and order, but separated by gene-rich segments present in only one or the other pair. The pattern is consistent with degenerate tetraploidy with numerous segmental deletions, some in one pair of colinear chromosomes and some in the other. Divergence in 1,000-bp windows varies along an alignment of a colinear pair, from zero to as much as 20% in a pattern consistent with gene conversion associated with recombinational repair of DNA double-strand breaks. Although pairs of colinear chromosomes are a characteristic of sexually reproducing diploids and polyploids, a quite different explanation for their presence in bdelloids is suggested by the recent finding that bdelloid rotifers can recover and resume reproduction after suffering hundreds of radiation-induced DNA double-strand breaks per oocyte nucleus. Because bdelloid primary oocytes are in G(1) and therefore lack sister chromatids, we propose that bdelloid colinear chromosome pairs are maintained as templates for the repair of DNA double-strand breaks caused by the frequent desiccation and rehydration characteristic of bdelloid habitats.

  20. Production of sunshine bass fingerlings without using rotifers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The accepted protocol for production of fingerling size sunshine bass in tanks included the feeding of rotifers for several days before the larvae were weaned to feed on Artemia nauplii. Maintaining rotifer cultures requires space, time, equipment, supplies, trained culturists and the cultures are ...

  1. Tank culture of sunshine bass without using rotifers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previously reported protocols for culture of sunshine bass larvae to fingerling size in tanks involved an initial feeding of rotifers for several days before the larvae were weaned to Artemia nauplii and prepared feed. Maintaining rotifer cultures requires space, time, equipment, supplies, and trai...

  2. Production of sunshine bass fingerlings in tanks without using rotifers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previously reported protocol for culture of sunshine bass larvae to fingerling size in tanks involved an initial feeding of rotifers for several days before the larvae are weaned to feed on Artemia nauplii. Maintaining rotifer cultures requires space, time, equipment, supplies, trained culturists a...

  3. Effects of population outcrossing on rotifer fitness

    PubMed Central

    2010-01-01

    Background Outcrossing between populations can exert either positive or negative effects on offspring fitness. Cyclically parthenogenetic rotifers, like other continental zooplankters, show high genetic differentiation despite their high potential for passive dispersal. Within this context, the effects of outcrossing may be relevant in modulating gene flow between populations through selection for or against interpopulation hybrids. Nevertheless, these effects remain practically unexplored in rotifers. Here, the consequences of outcrossing on the rotifer Brachionus plicatilis were investigated. Cross-mating experiments were performed between a reference population and three alternative populations that differed in their genetic distance with regard to the former. Two offspring generations were obtained: F1 and BC ('backcross'). Fitness of the outcrossed offspring was compared with fitness of the offspring of the reference population for both generations and for three different between-population combinations. Four fitness components were measured throughout the rotifer life cycle: the diapausing egg-hatching proportion, clone viability (for the clones originating from diapausing eggs), initial net growth rate R for each viable clone, and the proportion of male-producing clones. Additionally, both the parental fertilisation proportion and a compound fitness measure, integrating the complete life cycle, were estimated. Results In the F1 generation, hybrid vigour was detected for the diapausing egg-hatching proportion, while R was lower in the outcrossed offspring than in the offspring of the reference population. Despite these contrasting results, hybrid vigour was globally observed for the compound measure of fitness. Moreover, there was evidence that this vigour could increase with the genetic differentiation of the outcrossed populations. In the BC generation, the hybrid vigour detected for the egg-hatching proportion in the F1 generation reverted to outbreeding

  4. [Community structure of planktonic rotifers in the Pearl River Delta].

    PubMed

    Gao, Yuan; Li, Xin-Hui; Lai, Zi-Ni; Yu, Jing; Wang, Chao; Zeng, Yan-Yi; Liu, Qian-Fu; Yang, Wan-Ling

    2014-07-01

    Four ecological investigations were carried out on planktonic rotifers in Pearl River Delta in 2012. The community structure, including spatial and temporal patterns of species composition, dominant species, biomass and biodiversity, was investigated. The correlation between the community structure of rotifers and the environmental factors was discussed. Moreover, the aggregation structures of rotifers were analyzed. A total of 53 rotifer species were found. Dominant species changed markedly with season and space. Polyarthra trigla had higher dominance. In terms of seasonal changes, the density and biomass were higher in dry season than in wet season, while the biodiversity and evenness indices were vice versa. The biomass and biodiversity of rotifers showed highly significant differences among seasons. In terms of spatial distribution, the average density and the average biomass showed an increase from the southwest to the northeast. The highest density and biomass were recorded in Shiqiao. The biodiversity and evenness indices had an opposite spatial distribution, with the highest values being recorded in Qingqi. The rotifer density was significantly different among the investigated sites, while the biomass and biodiversity were not significantly different. Correlation analysis demonstrated a highly significant positive correlation between rotifer density and biomass, as well as between biodiversity and evenness indices, and a highly negative correlation between biodiversity and biomass. The biodiversity and evenness indices both decreased markedly with the increase of biomass. Principal component analysis indicated that the rotifer density was closely correlated with environment factors, such as water temperature, pH, dissolved oxy- gen, chlorophyll a content, total phosphorus, and total nitrogen, in different seasons. Aggregation analysis based on rotifer density revealed five aggregation structures in the investigated sites, indicating significant differences

  5. Relationship between the flagellates and the ciliates.

    PubMed Central

    Lee, R E; Kugrens, P

    1992-01-01

    The flagellates and the ciliates have long been considered to be closely related because of their unicellular nature and the similarity in the structures of the axoneme of the flagella and cilia in both groups. Most protozoologists believe that the ciliates arose from a flagellate. The flagellates that are most similar in structure to the ciliates are the dinoflagellates and two genera of uncertain taxonomic position, Colponema and Katablepharis. Structurally, dinoflagellates have a number of similarities with ciliates. These include the similarity of the cortical alveoli in the ciliates to the thecal vesicles in the dinoflagellates, the possession of tubular cristae, the similarity of the parasomal sac of the ciliates to the pusule of the dinoflagellates, the possession of similar trichocysts and mucocysts, and some similarity in the feeding apparatus. Colponema spp. are probably related to the dinoflagellates and have many of the same similarities with the ciliates. Katablepharis spp. are very similar in structure to the swarmer (embryo) of the suctorian ciliates. Indeed, reduction in the number of cilia to two in the suctorian swarmer and elimination of the macronucleus would result in a cell that is very similar to the Katablepharis cell. The feeding apparatus of Katablepharis spp. and the rest of the ciliates consists of two concentric microtubular arrays associated with vesicles. Information available from nucleotide sequencing of rRNA places the dinoflagellates in an ancestral position to the ciliates. The rRNA of Colponema and Katablepharis spp. has not yet been investigated. The use of stop codons in mRNA is discussed in relation to phylogeny. Images PMID:1480107

  6. Evolution of parasitism in kinetoplastid flagellates.

    PubMed

    Lukeš, Julius; Skalický, Tomáš; Týč, Jiří; Votýpka, Jan; Yurchenko, Vyacheslav

    2014-07-01

    Kinetoplastid protists offer a unique opportunity for studying the evolution of parasitism. While all their close relatives are either photo- or phagotrophic, a number of kinetoplastid species are facultative or obligatory parasites, supporting a hypothesis that parasitism has emerged within this group of flagellates. In this review we discuss origin and evolution of parasitism in bodonids and trypanosomatids and specific adaptations allowing these protozoa to co-exist with their hosts. We also explore the limits of biodiversity of monoxenous (one host) trypanosomatids and some features distinguishing them from their dixenous (two hosts) relatives.

  7. Studies on comparative population growth of some species of the rotifer Lecane (Rotifera).

    PubMed

    Serrania-Soto, C R; Sarma, S S S; Nandini, S

    2011-07-01

    We compared the population growth patterns of 5 species of the rotifer genus Lecane [(L. quadridentata (Ehrenberg, 1830), L. comuta (Muller, 1786), L. papuana (Murray, 1913), L. unguitata (Fadeev, 1925) and L. pyriformis (Daday, 1905)] ranging in adult average body size from 30 to 140 microm. All species were cultured under laboratory conditions for 25-30 days using the green alga Scenedesmus acutus as the exclusive diet, at a density of 1.0 x 10(6) cells ml(-1) at 24 degrees C. Regardless of the species, lecanids reached their peak population densities after 4 weeks. Peak population densities ranged from 15 to 320 ind. ml(-1), depending on body size. There was an inverse curvilinear relation between body lengths and peak population abundances (densities) of the Lecane species. Egg ratios (eggs per female) for the tested species were < 0.6 during the exponential phase but declined to 0.1 (or lower) as the population density increased. The rates of population increase for the lecanids were in general lower(0.10 to 0.21 day (-1)) than other well-studied rotifer species including members of Brachionidae.

  8. Effect of high levels of the rotifer Lecane inermis on the ciliate community in laboratory-scale sequencing batch bioreactors (SBRs).

    PubMed

    Fyda, Janusz; Babko, Roman; Fiałkowska, Edyta; Pajdak-Stós, Agnieszka; Kocerba-Soroka, Wioleta; Sobczyk, Mateusz; Sobczyk, Łukasz

    2015-10-01

    Due to its ability to feed on filamentous bacteria, the rotifer Lecane inermis has already been recognized as a potential control agent of activated sludge bulking, which is usually caused by the excessive growth of filamentous microorganisms. However, their effectiveness depends, in part, on their abundance. We studied the influence of high densities of L. inermis on the protozoan community in activated sludge from a wastewater treatment plant (WWTP) in 4 laboratory-scale sequencing batch bioreactors (SBRs). Two treatments and two controls were subjected to nutrient removal system in process similar to that used in a WWTP. The experiment lasted 9 days and was repeated in 24-h cycles, including phases of agitation with feeding, aeration and agitation and sedimentation with decantation at the end of the cycle. In total, 32 taxa were identified, among which 25 were ciliated protozoa, 4 were amoebae, 2 were flagellates, and one was a nematode. Rotifers were then introduced to 2 bioreactors at a final concentration of 500ind.mL(-1), and the taxonomic composition and abundance of the activated sludge microfauna were assessed 2, 5 and 8 days thereafter. The mean density of ciliates on the first day of experiment was 12,610ind.mL(-1) and diminished to 4868±432ind.mL-±432ind.mL(-1) in the control and 5496±638ind.mL(-1) in the rotifer-treated group on the last day. Thus, even extremely high densities of artificially introduced rotifers did not negatively affect the protozoan community. On the contrary, the protozoan community was more diverse in the treatment group than in the control.

  9. Small but Manifold - Hidden Diversity in "Spumella-like Flagellates".

    PubMed

    Grossmann, Lars; Bock, Christina; Schweikert, Michael; Boenigk, Jens

    2016-07-01

    Colourless, nonscaled chrysophytes comprise morphologically similar or even indistinguishable flagellates which are important bacterivors in water and soil crucial for ecosystem functioning. However, phylogenetic analyses indicate a multiple origin of such colourless, nonscaled flagellate lineages. These flagellates are often referred to as "Spumella-like flagellates" in ecological and biogeographic studies. Although this denomination reflects an assumed polyphyly, it obscures the phylogenetic and taxonomic diversity of this important flagellate group and, thus, hinders progress in lineage- and taxon-specific ecological surveys. The smallest representatives of colourless chrysophytes have been addressed in very few taxonomic studies although they are among the dominant flagellates in field communities. To overcome the blurred picture and set the field for further investigation in biogeography and ecology of the organisms in question, we studied a set of strains of specifically small, colourless, nonscaled chrysomonad flagellates by means of electron microscopy and molecular analyses. They were isolated by a filtration-acclimatisation approach focusing on flagellates of around 5 μm. We present the phylogenetic position of eight different lineages on both the ordinal and the generic level. Accordingly, we describe the new genera Apoikiospumella, Chromulinospumella, Segregatospumella, Cornospumella and Acrispumella Boenigk et Grossmann n. g. and different species within them.

  10. Flagellated ectosymbiotic bacteria propel a eucaryotic cell.

    PubMed

    Tamm, S L

    1982-09-01

    A devescovinid flagellate from termites exhibits rapid gliding movements only when in close contact with other cells or with a substrate. Locomotion is powered not by the cell's own flagella nor by its remarkable rotary axostyle, but by the flagella of thousands of rod bacteria which live on its surface. That the ectosymbiotic bacteria actually propel the protozoan was shown by the following: (a) the bacteria, which lie in specialized pockets of the host membrane, bear typical procaryotic flagella on their exposed surface; (b) gliding continues when the devescovinid's own flagella and rotary axostyle are inactivated; (c) agents which inhibit bacterial flagellar motility, but not the protozoan's motile systems, stop gliding movements; (d) isolated vesicles derived from the surface of the devescovinid rotate at speeds dependent on the number of rod bacteria still attached; (e) individual rod bacteria can move independently over the surface of compressed cells; and (f) wave propagation by the flagellar bundles of the ectosymbiotic bacteria is visualized directly by video-enhanced polarization microscopy. Proximity to solid boundaries may be required to align the flagellar bundles of adjacent bacteria in the same direction, and/or to increase their propulsive efficiency (wall effect). This motility-linked symbiosis resembles the association of locomotory spirochetes with the Australian termite flagellate Mixotricha (Cleveland, L. R., and A. V. Grimstone, 1964, Proc. R. Soc. Lond. B Biol. Sci., 159:668-686), except that in our case propulsion is provided by bacterial flagella themselves. Since bacterial flagella rotate, an additional novelty of this system is that the surface bearing the procaryotic rotary motors is turned by the eucaryotic rotary motor within.

  11. Euglenoid flagellates: a multifaceted biotechnology platform.

    PubMed

    Krajčovič, Juraj; Matej Vesteg; Schwartzbach, Steven D

    2015-05-20

    Euglenoid flagellates are mainly fresh water protists growing in highly diverse environments making them well-suited for a multiplicity of biotechnology applications. Phototrophic euglenids possesses complex chloroplasts of green algal origin bounded by three membranes. Euglena nuclear and plastid genome organization, gene structure and gene expression are distinctly different from other organisms. Our observations on the model organism Euglena gracilis indicate that transcription of both the plastid and nuclear genome is insensitive to environmental changes and that gene expression is regulated mainly at the post-transcriptional level. Euglena plastids have been proposed as a site for the production of proteins and value added metabolites of biotechnological interest. Euglena has been shown to be a suitable protist species to be used for production of several compounds that are used in the production of cosmeceuticals and nutraceuticals, such as α-tocopherol, wax esters, polyunsaturated fatty acids, biotin and tyrosine. The storage polysaccharide, paramylon, has immunostimulatory properties and has shown a promise for biomaterials production. Euglena biomass can be used as a nutritional supplement in aquaculture and in animal feed. Diverse applications of Euglena in environmental biotechnology include ecotoxicological risk assessment, heavy metal bioremediation, bioremediation of industrial wastewater and contaminated water.

  12. Synthesis and assembly of the cytoskeleton of Naegleria gruberi flagellates

    PubMed Central

    1984-01-01

    When Naegleria gruberi flagellates were extracted with nonionic detergent and stained by the indirect immunofluorescence method with AA- 4.3 (a monoclonal antibody against Naegleria beta-tubulin), flagella and a network of cytoskeletal microtubules (CSMT) were seen. When Naegleria amebae were examined in the same way, no cytoplasmic tubulin- containing structures were seen. Formation of the flagellate cytoskeleton was followed during the differentiation of amebae into flagellates by staining cells with AA-4.3. The first tubulin containing structures were a few cytoplasmic microtubules that formed at the time amebae rounded up into spherical cells. The formation of these microtubules was followed by the appearance of basal bodies and flagella and then by the formation of the CSMT. The CSMT formed before the cells assumed the flagellate shape. In flagellate shaped cells the CSMT radiate from the base of the flagella and follow a curving path the full length of the cell. Protein synthetic requirements for the formation of CSMT were examined by transferring cells to cycloheximide at various times after initiation. One-half the population completed the protein synthesis essential for formation of CSMT 61 min after initiation of the differentiation. This is 10 min after the time when protein synthesis for formation of flagella is completed and 10-15 min before the time when the protein synthesis necessary for formation of the flagellate shape is completed. PMID:6363422

  13. Synthesis and assembly of the cytoskeleton of Naegleria gruberi flagellates.

    PubMed

    Walsh, C

    1984-02-01

    When Naegleria gruberi flagellates were extracted with nonionic detergent and stained by the indirect immunofluorescence method with AA-4.3 (a monoclonal antibody against Naegleria beta-tubulin), flagella and a network of cytoskeletal microtubules (CSMT) were seen. When Naegleria amebae were examined in the same way, no cytoplasmic tubulin-containing structures were seen. Formation of the flagellate cytoskeleton was followed during the differentiation of amebae into flagellates by staining cells with AA-4.3. The first tubulin containing structures were a few cytoplasmic microtubules that formed at the time amebae rounded up into spherical cells. The formation of these microtubules was followed by the appearance of basal bodies and flagella and then by the formation of the CSMT. The CSMT formed before the cells assumed the flagellate shape. In flagellate shaped cells the CSMT radiate from the base of the flagella and follow a curving path the full length of the cell. Protein synthetic requirements for the formation of CSMT were examined by transferring cells to cycloheximide at various times after initiation. One-half the population completed the protein synthesis essential for formation of CSMT 61 min after initiation of the differentiation. This is 10 min after the time when protein synthesis for formation of flagella is completed and 10-15 min before the time when the protein synthesis necessary for formation of the flagellate shape is completed. PMID:6363422

  14. Larvicidal algae.

    PubMed

    Marten, Gerald G

    2007-01-01

    Although most algae are nutritious food for mosquito larvae, some species kill the larvae when ingested in large quantities. Cyanobacteria (blue-green algae) that kill larvae do so by virtue of toxicity. While blue-green algae toxins may offer possibilities for delivery as larvicides, the toxicity of live blue-green algae does not seem consistent enough for live algae to be useful for mosquito control. Certain species of green algae in the order Chlorococcales kill larvae primarily because they are indigestible. Where these algae are abundant in nature, larvae consume them to the exclusion of other food and then starve. Under the right circumstances, it is possible to introduce indigestible algae into a breeding habitat so they become abundant enough to render it unsuitable for mosquito production. The algae can persist for years, even if the habitat dries periodically. The main limitation of indigestible algae lies in the fact that, under certain conditions, they may not replace all the nutritious algae in the habitat. More research on techniques to ensure complete replacement will be necessary before indigestible algae can go into operational use for mosquito control.

  15. Extreme resistance of bdelloid rotifers to ionizing radiation

    PubMed Central

    Gladyshev, Eugene; Meselson, Matthew

    2008-01-01

    Rotifers of class Bdelloidea are common invertebrate animals with highly unusual characteristics, including apparently obligate asexuality, the ability to resume reproduction after desiccation at any life stage, and a paucity of transposable genetic elements of types not prone to horizontal transmission. We find that bdelloids are also extraordinarily resistant to ionizing radiation (IR). Reproduction of the bdelloids Adineta vaga and Philodina roseola is much more resistant to IR than that of Euchlanis dilatata, a rotifer belonging to the desiccation-intolerant and facultatively sexual class Monogononta, and all other animals for which we have found relevant data. By analogy with the desiccation- and radiation-resistant bacterium Deinococcus radiodurans, we suggest that the extraordinary radiation resistance of bdelloid rotifers is a consequence of their evolutionary adaptation to survive episodes of desiccation encountered in their characteristic habitats and that the damage incurred in such episodes includes DNA breakage that is repaired upon rehydration. Such breakage and repair may have maintained bdelloid chromosomes as colinear pairs and kept the load of transposable genetic elements low and may also have contributed to the success of bdelloid rotifers in avoiding the early extinction suffered by most asexuals. PMID:18362355

  16. Gravitational sensory transduction chain in flagellates

    NASA Astrophysics Data System (ADS)

    Häder, D.-P.; Richter, P.; Ntefidou, M.; Lebert, M.

    Earlier hypotheses have assumed that gravitactic orientation in flagellates, such as the photosynthetic unicell Euglena gracilis, is brought about by passive alignment of the cells in the water column by being tail heavy. A recent experiment on a sounding rocket (TEXUS 40) comparing immobilized cells with mobile cells demonstrated that the passive buoy effect can account for approximately 20% of the orientation of the cells in a gravity field. The cells show either positive or negative gravitaxis depending on other external or internal factors. Shortly after inoculation, the tendency of young cells to swim downward in the water column can be readily reverted by adding micromolar concentrations of some heavy metal ions including copper, cadmium or lead. The negative gravitaxis of older cells is converted into a positive one by stress factors such as increasing salinity or exposure to excessive visible or UV radiation. The mechanism for this switch seems to involve reactive oxygen species since the gravitactic sign change was suppressed when oxygen was removed by flushing the cell suspension with nitrogen. Also, the addition of radical scavengers (Trolox, ascorbic acid or potassium cyanide) abolished or reduced the gravitactic sign change. Addition of hydrogen peroxide induced a gravitactic sign change in the absence of external stress factors. The primary reception for the gravity vector seems to involve mechanosensitive ion channels which specifically gate calcium ions inward. We have identified several gene sequences for putative mechanosensory channels in Euglena and have applied RNAi to identify which of these channels are involved in graviperception. The influx of Ca 2+ activates calmodulin (CaM) which has been shown to be involved in the sensory transduction chain of graviorientation. It is known that an adenylyl cyclase is bound to the flagellar membrane in Euglena which is activated by CaM. This enzyme produces cAMP which has also been shown to be the key

  17. Does Haplodiploidy Purge Inbreeding Depression in Rotifer Populations?

    PubMed Central

    Tortajada, Ana M.; Carmona, María José; Serra, Manuel

    2009-01-01

    Background Inbreeding depression is an important evolutionary factor, particularly when new habitats are colonized by few individuals. Then, inbreeding depression by drift could favour the establishment of later immigrants because their hybrid offspring would enjoy higher fitness. Rotifers are the only major zooplanktonic group where information on inbreeding depression is still critically scarce, despite the fact that in cyclical parthenogenetic rotifers males are haploid and could purge deleterious recessive alleles, thereby decreasing inbreeding depression. Methodology/Principal Findings We studied the effects of inbreeding in two populations of the cyclical parthenogenetic rotifer Brachionus plicatilis. For each population, we compared both the parental fertilization proportion and F1 fitness components from intraclonal (selfed) and interclonal (outcrossed) crosses. The parental fertilization proportion was similar for both types of crosses, suggesting that there is no mechanism to avoid selfing. In the F1 generation of both populations, we found evidence of inbreeding depression for the fitness components associated with asexual reproduction; whereas inbreeding depression was only found for one of the two sexual reproduction fitness components measured. Conclusions/Significance Our results show that rotifers, like other major zooplanktonic groups, can be affected by inbreeding depression in different stages of their life cycle. These results suggest that haplodiploidy does not purge efficiently deleterious recessive alleles. The inbreeding depression detected here has important implications when a rotifer population is founded and intraclonal crossing is likely to occur. Thus, during the foundation of new populations inbreeding depression may provide opportunities for new immigrants, increasing gene flow between populations, and affecting genetic differentiation. PMID:19997616

  18. The evolutionary expansion of the trypanosomatid flagellates.

    PubMed

    Vickerman, K

    1994-12-01

    The trypanosomatids combine a relatively uniform morphology with ability to parasitise a very diverse range of hosts including animals, plants and other protists. Along with their sister family, the biflagellate bodonids, they are set apart from other eukaryotes by distinctive organisational features, such as the kinetoplast-mitochondrion and RNA editing, isolation of glycolysis enzymes in the glycosome, use of the flagellar pocket for molecular traffic into and out of the cell, a unique method of generating cortical microtubules, and bizarre nuclear organisation. These features testify to the antiquity and isolation of the kinetoplast-bearing flagellates (Kinetoplastida). Molecular sequencing techniques (especially small subunit ribosomal RNA gene sequencing) are now radically reshaping previous ideas on the phylogeny of these organisms. The idea that the monogenetic (MG) trypanosomatids gave rise to the digenetic (DG) genera is losing ground to a view that, after the bodonids, the African trypanosomes (DG) represent the most ancient lineage, followed by Trypanosoma cruzi (DG), then Blastocrithidia (MG), Herpetomonas (MG) and Phytomonas (DG), with Leptomonas (MG), Crithidia (MG), Leishmania (DG) and Endotrypanum (DG) forming the crown of the evolutionary tree. Vast genetic distances (12% divergence) separate T. brucei and T. cruzi, while the Leishmania species are separated by very short distances (less than 1% divergence). These phylogenetic conclusions are supported by studies on RNA editing and on the nature of the parasite surface. The trypanosomatids seem to be able to adapt with ease their energy metabolism to the availability of substrates and oxygen, and this may give them the ability to institute new life cycles if host behaviour patterns allow. Sexual processes, though present in at least some trypanosomatids, may have played only a minor part in generating diversity during trypanosomatid evolution. On the other hand, the development of altruistic

  19. EST analysis of the scaly green flagellate Mesostigma viride (Streptophyta): Implications for the evolution of green plants (Viridiplantae)

    PubMed Central

    Simon, Andreas; Glöckner, Gernot; Felder, Marius; Melkonian, Michael; Becker, Burkhard

    2006-01-01

    Background The Viridiplantae (land plants and green algae) consist of two monophyletic lineages, the Chlorophyta and the Streptophyta. The Streptophyta include all embryophytes and a small but diverse group of freshwater algae traditionally known as the Charophyceae (e.g. Charales, Coleochaete and the Zygnematales). The only flagellate currently included in the Streptophyta is Mesostigma viride Lauterborn. To gain insight into the genome evolution in streptophytes, we have sequenced 10,395 ESTs from Mesostigma representing 3,300 independent contigs and compared the ESTs of Mesostigma with available plant genomes (Arabidopsis, Oryza, Chlamydomonas), with ESTs from the bryophyte Physcomitrella, the genome of the rhodophyte Cyanidioschyzon, the ESTs from the rhodophyte Porphyra, and the genome of the diatom Thalassiosira. Results The number of expressed genes shared by Mesostigma with the embryophytes (90.3 % of the expressed genes showing similarity to known proteins) is higher than with Chlamydomonas (76.1 %). In general, cytosolic metabolic pathways, and proteins involved in vesicular transport, transcription, regulation, DNA-structure and replication, cell cycle control, and RNA-metabolism are more conserved between Mesostigma and the embryophytes than between Mesostigma and Chlamydomonas. However, plastidic and mitochondrial metabolic pathways, cytoskeletal proteins and proteins involved in protein folding are more conserved between Mesostigma and Chlamydomonas than between Mesostigma and the embryophytes. Conclusion Our EST-analysis of Mesostigma supports the notion that this organism should be a suitable unicellular model for the last flagellate common ancestor of the streptophytes. Mesostigma shares more genes with the embryophytes than with the chlorophyte Chlamydomonas reinhardtii, although both organisms are flagellate unicells. Thus, it seems likely that several major physiological changes (e.g. in the regulation of photosynthesis and photorespiration

  20. Environmental DNA sequencing primers for eutardigrades and bdelloid rotifers

    PubMed Central

    2009-01-01

    Background The time it takes to isolate individuals from environmental samples and then extract DNA from each individual is one of the problems with generating molecular data from meiofauna such as eutardigrades and bdelloid rotifers. The lack of consistent morphological information and the extreme abundance of these classes makes morphological identification of rare, or even common cryptic taxa a large and unwieldy task. This limits the ability to perform large-scale surveys of the diversity of these organisms. Here we demonstrate a culture-independent molecular survey approach that enables the generation of large amounts of eutardigrade and bdelloid rotifer sequence data directly from soil. Our PCR primers, specific to the 18s small-subunit rRNA gene, were developed for both eutardigrades and bdelloid rotifers. Results The developed primers successfully amplified DNA of their target organism from various soil DNA extracts. This was confirmed by both the BLAST similarity searches and phylogenetic analyses. Tardigrades showed much better phylogenetic resolution than bdelloids. Both groups of organisms exhibited varying levels of endemism. Conclusion The development of clade-specific primers for characterizing eutardigrades and bdelloid rotifers from environmental samples should greatly increase our ability to characterize the composition of these taxa in environmental samples. Environmental sequencing as shown here differs from other molecular survey methods in that there is no need to pre-isolate the organisms of interest from soil in order to amplify their DNA. The DNA sequences obtained from methods that do not require culturing can be identified post-hoc and placed phylogenetically as additional closely related sequences are obtained from morphologically identified conspecifics. Our non-cultured environmental sequence based approach will be able to provide a rapid and large-scale screening of the presence, absence and diversity of Bdelloidea and Eutardigrada in

  1. Multiple stressor effects of predation by rotifers and herbicide pollution on different Chlamydomonas strains and potential impacts on population dynamics.

    PubMed

    Fischer, Beat B; Roffler, Severin; Eggen, Rik I L

    2012-12-01

    Environmental factors can interact with the effects of chemical pollutants on natural systems by inducing multiple stressor effects in individual organisms as well as by altering selection pressure on tolerant strains in heterogeneous populations. Predation is a stressful environmental factor relevant for many species. Therefore, the impact of predation by the rotifer Brachionus calyciflorus on tolerance of eight genetically different strains of the green alga Chlamydomonas reinhardtii to simultaneous exposure to each of the three herbicides (diuron, paraquat, and S-metolachlor) was tested. Interactions of combined stressors were analyzed based on the independent action model; additive, synergistic, and antagonistic effects of the combined exposure could be detected depending on the herbicide and strain tested. If cultures were acclimated (pre-exposed) to one stressor, tolerance to the second stressor could be increased. This indicates that physiological changes can induce cotolerance of predation-exposed algae to herbicides and of herbicide-treated algae to predation depending on the combination of stressors. The strain-specific differences in multiple stressor effects also changed the correlation of strains' tolerances to individual stressors determined during combined and single-stressor exposure. Changes in cotolerance to stressors affect selection pressure and population dynamics during long-term exposure. This shows that predation stress can have adverse effects on the toxicity of chemical pollutants to microalgae on the organism and population levels.

  2. Multiple stressor effects of predation by rotifers and herbicide pollution on different Chlamydomonas strains and potential impacts on population dynamics.

    PubMed

    Fischer, Beat B; Roffler, Severin; Eggen, Rik I L

    2012-12-01

    Environmental factors can interact with the effects of chemical pollutants on natural systems by inducing multiple stressor effects in individual organisms as well as by altering selection pressure on tolerant strains in heterogeneous populations. Predation is a stressful environmental factor relevant for many species. Therefore, the impact of predation by the rotifer Brachionus calyciflorus on tolerance of eight genetically different strains of the green alga Chlamydomonas reinhardtii to simultaneous exposure to each of the three herbicides (diuron, paraquat, and S-metolachlor) was tested. Interactions of combined stressors were analyzed based on the independent action model; additive, synergistic, and antagonistic effects of the combined exposure could be detected depending on the herbicide and strain tested. If cultures were acclimated (pre-exposed) to one stressor, tolerance to the second stressor could be increased. This indicates that physiological changes can induce cotolerance of predation-exposed algae to herbicides and of herbicide-treated algae to predation depending on the combination of stressors. The strain-specific differences in multiple stressor effects also changed the correlation of strains' tolerances to individual stressors determined during combined and single-stressor exposure. Changes in cotolerance to stressors affect selection pressure and population dynamics during long-term exposure. This shows that predation stress can have adverse effects on the toxicity of chemical pollutants to microalgae on the organism and population levels. PMID:22996994

  3. The Study of Algae

    ERIC Educational Resources Information Center

    Rushforth, Samuel R.

    1977-01-01

    Included in this introduction to the study of algae are drawings of commonly encountered freshwater algae, a summary of the importance of algae, descriptions of the seven major groups of algae, and techniques for collection and study of algae. (CS)

  4. Sexual Reproductive Biology of a Colonial Rotifer Sinantherina socialis (Rotifera: Monogononta): Do mating strategies vary between colonial and solitary rotifer species?

    PubMed

    Rico-Martínez, Roberto; Walsh, Elizabeth J

    2013-12-01

    In many aquatic invertebrates including monogonont rotifers, sex provides genetic variation and dormant stages that allows dispersal in time and space. While the reproductive biology of some solitary monogonont rotifer species is known, little is known concerning mating behaviors in colonial rotifers. Coloniality poses unique challenges to the typical mating behavior of solitary rotifers. For instance, most species engage in circling behavior, where the male swims in close proximity to the female. In colonial forms, access to a particular female may be hindered by nearby colony mates. Here we provide descriptions of (1) male morphology, (2) mating behavior, and (3) types of eggs of the widespread colonial rotifer Sinantherina socialis, and discuss modifications in mating strategies as a consequence of coloniality. Two important differences from mating patterns documented in solitary rotifers were found in S. socialis. First, duration of circling phase of mating is protracted for males encountering small colonies of females as compared to solitary females. Males encountering single females removed from their colonies behave similarly to those of solitary species. Second, duration of copulation in S. socialis is the shortest reported for any rotifer species. Endogamy might occur in this species as sons copulate with their sisters and mothers, at least under laboratory conditions. Examples of behaviour in linked video clips.

  5. The toxicity of carbofuran to the freshwater rotifer, Philodina roseola.

    PubMed

    Moreira, Raquel Aparecida; da Silva Mansano, Adrislaine; Rocha, Odete

    2015-04-01

    In this study, the effects of exposing the rotifer Philodina roseola to the pesticide carbofuran were investigated. Its range of sensitivity to potassium dichromate, the acute toxicity of active ingredient carbofuran and of carbofuran dosed as its commercial form, Furadan(®) 350 SC were determined. Chronic toxicity of carbofuran dosed as Furadan(®) 350 SC on P. roseola survival and fecundity were also studied. The sensitivity of P. roseola to K2Cr2O7 ranged from 29.52 to 64.67 mg L(-1), averaging 47.10 mg L(-1). The 48-h EC50 were 13.36 ± 2.63 mg L(-1) for carbofuran and 89.32 ± 6.52 mg L(-1) for commercial form. Chronic toxicity tests showed that the survival of this rotifer was not affected by the carbofuran dosed as Furadan(®) 350 SC at the concentrations tested and that at 1.56 and 3.12 mg L(-1) their fecundity was higher than in the absence of this commercial product, characterizing the hormesis phenomenon. The sensitivity profile of several species to carbofuran indicated that P. roseola is more susceptible to this pesticide than the fish Clarias batrachus, the bacterium Vibrio fischeri, the protozoan Paramecium caudatum and the rotifer Brachionus calyciflorus, although the acute toxicity of carbofuran dosed as Furadan(®) 350 SC to P. roseola is much lower than that of active ingredient carbofuran. The results also imply that the exacerbated use of pesticides and the constant, accelerated expansion of agricultural activity will make aquatic non-target species even more vulnerable. Furthermore, the relevant role of benthic organisms in aquatic environments justifies the inclusion of P. roseola and other benthic species in toxicity screening for risk assessment, regarding this environmental compartment. PMID:25588673

  6. The toxicity of carbofuran to the freshwater rotifer, Philodina roseola.

    PubMed

    Moreira, Raquel Aparecida; da Silva Mansano, Adrislaine; Rocha, Odete

    2015-04-01

    In this study, the effects of exposing the rotifer Philodina roseola to the pesticide carbofuran were investigated. Its range of sensitivity to potassium dichromate, the acute toxicity of active ingredient carbofuran and of carbofuran dosed as its commercial form, Furadan(®) 350 SC were determined. Chronic toxicity of carbofuran dosed as Furadan(®) 350 SC on P. roseola survival and fecundity were also studied. The sensitivity of P. roseola to K2Cr2O7 ranged from 29.52 to 64.67 mg L(-1), averaging 47.10 mg L(-1). The 48-h EC50 were 13.36 ± 2.63 mg L(-1) for carbofuran and 89.32 ± 6.52 mg L(-1) for commercial form. Chronic toxicity tests showed that the survival of this rotifer was not affected by the carbofuran dosed as Furadan(®) 350 SC at the concentrations tested and that at 1.56 and 3.12 mg L(-1) their fecundity was higher than in the absence of this commercial product, characterizing the hormesis phenomenon. The sensitivity profile of several species to carbofuran indicated that P. roseola is more susceptible to this pesticide than the fish Clarias batrachus, the bacterium Vibrio fischeri, the protozoan Paramecium caudatum and the rotifer Brachionus calyciflorus, although the acute toxicity of carbofuran dosed as Furadan(®) 350 SC to P. roseola is much lower than that of active ingredient carbofuran. The results also imply that the exacerbated use of pesticides and the constant, accelerated expansion of agricultural activity will make aquatic non-target species even more vulnerable. Furthermore, the relevant role of benthic organisms in aquatic environments justifies the inclusion of P. roseola and other benthic species in toxicity screening for risk assessment, regarding this environmental compartment.

  7. The Selective Use of Hypochlorite to Prevent Pond Crashes for Algae-Biofuel Production.

    PubMed

    Park, Sichoon; Van Ginkel, Steven W; Pradeep, Priya; Igou, Thomas; Yi, Christine; Snell, Terry; Chen, Yongsheng

    2016-01-01

    Although algae-biofuels have many advantages including high areal productivity, algae can be preyed upon by amoebas, protozoans, ciliates, and rotifers, particularly in open pond systems. Thus, these higher organisms need to be controlled. In this study, Chlorella kessleri was used as the algal culture and Brachionus calyciflorus as the source of predation. The effect of sodium hypochlorite (bleach) was tested with the goal of totally inhibiting the rotifer while causing minor inhibition to the alga. The 24-hr LC(50) for B. calyciflorus in spring water was 0.198 mg Cl/L while the 24-hr LC(50) for C. kessleri was 0.321 mg Cl/L. However, chlorine dissipates rapidly as the algae serves as reductant. Results showed a chlorine dosage between 0.45 to 0.6 mg Cl/L and a dosing interval of two hours created the necessary chlorine concentrations to inhibit predation while letting the algae grow; thus giving algae farmers a tool to prevent pond crashes.

  8. Snow algae of the Sierra Nevada, Spain, and High Atlas mountains of Morocco.

    PubMed

    Duval, B; Duval, E; Hoham, R W

    1999-03-01

    Snow algae (Chlorophyta) are reported from the Sierra Nevada mountains in southern Spain and the High Atlas mountains of Morocco. Populations of the snow algae Chlamydomonas sp., coloring the snow orange-red, were collected from Pico de Veleta, Spain, while snow samples from Mt. Neltner in the High Atlas mountains, contained resting spores of an orange-green colored Chloromonas sp. Other microbes observed in snow samples include bacteria, fungi, heterotrophic euglenids, diatoms, nematodes, and heterotrophic mastigotes (flagellated protists). This is the first report of snow algae from the Sierra Nevada mountains of Spain and from the Afro-alpine environment.

  9. Inventory and Phylogenetic Analysis of Meiotic Genes in Monogonont Rotifers

    PubMed Central

    2013-01-01

    A long-standing question in evolutionary biology is how sexual reproduction has persisted in eukaryotic lineages. As cyclical parthenogens, monogonont rotifers are a powerful model for examining this question, yet the molecular nature of sexual reproduction in this lineage is currently understudied. To examine genes involved in meiosis, we generated partial genome assemblies for 2 distantly related monogonont species, Brachionus calyciflorus and B. manjavacas. Here we present an inventory of 89 meiotic genes, of which 80 homologs were identified and annotated from these assemblies. Using phylogenetic analysis, we show that several meiotic genes have undergone relatively recent duplication events that appear to be specific to the monogonont lineage. Further, we compare the expression of “meiosis-specific” genes involved in recombination and all annotated copies of the cell cycle regulatory gene CDC20 between obligate parthenogenetic (OP) and cyclical parthenogenetic (CP) strains of B. calyciflorus. We show that “meiosis-specific” genes are expressed in both CP and OP strains, whereas the expression of one of the CDC20 genes is specific to cyclical parthenogenesis. The data presented here provide insights into mechanisms of cyclical parthenogenesis and establish expectations for studies of obligate asexual relatives of monogononts, the bdelloid rotifer lineage. PMID:23487324

  10. Long-Term Coexistence of Rotifer Cryptic Species

    PubMed Central

    Serra, Manuel; Gómez, Africa

    2011-01-01

    Despite their high morphological similarity, cryptic species often coexist in aquatic habitats presenting a challenge in the framework of niche differentiation theory and coexistence mechanisms. Here we use a rotifer species complex inhabiting highly unpredictable and fluctuating salt lakes to gain insights into the mechanisms involved in stable coexistence in cryptic species. We combined molecular barcoding surveys of planktonic populations and paleogenetic analysis of diapausing eggs to reconstruct the current and historical coexistence dynamics of two highly morphologically similar rotifer species, B. plicatilis and B. manjavacas. In addition, we carried out laboratory experiments using clones isolated from eight lakes where both species coexist to explore their clonal growth responses to salinity, a challenging, highly variable and unpredictable condition in Mediterranean salt lakes. We show that both species have co-occurred in a stable way in one lake, with population fluctuations in which no species was permanently excluded. The seasonal occurrence patterns of the plankton in two lakes agree with laboratory experiments showing that both species differ in their optimal salinity. These results suggest that stable species coexistence is mediated by differential responses to salinity and its fluctuating regime. We discuss the role of fluctuating salinity and a persistent diapausing egg banks as a mechanism for species coexistence in accordance with the ‘storage effect’. PMID:21738691

  11. Surviving starvation: changes accompanying starvation tolerance in a bdelloid rotifer.

    PubMed

    Marotta, Roberto; Uggetti, Andrea; Ricci, Claudia; Leasi, Francesca; Melone, Giulio

    2012-01-01

    Bdelloid rotifers survive desiccation and starvation by halting activity and entering a kind of dormancy. To understand the mechanisms of survival in the absence of food source, we studied the anatomical and ultrastructural changes occurring in a bdelloid species, Macrotrachela quadricornifera Milne 1886, after starvation for different periods. The starved rotifers present a progressive reduction of body size accompanied with a consistent reduction of the volume of the stomach syncytium, where lipid inclusions and digestive vacuoles tend to fade with prolonged starvation. Similar reduction occurs in the vitellarium gland, in which yolk granules progressively decrease in number and size. The changes observed in the syncytia of the stomach and the vitellarium suggest that during starvation M. quadricornifera uses resources diverted from the stomach syncytium first and from the vitellarium syncytium later, resources that are normally allocated to reproduction. The fine structure of starved bdelloids is compared with that of anhydrobiotic bdelloids, revealing that survival during either forms of dormancy is sustained by different physiological mechanisms.

  12. Planktonic Rotifers in a Subtropical Shallow Lake: Succession, Relationship to Environmental Factors, and Use as Bioindicators

    PubMed Central

    Wang, Xianyun; Wang, Liqing

    2013-01-01

    Changes in the density and species composition of planktonic rotifers as well as their relationship to several environmental variables were studied at Dadian Lake, a shallow subtropical lake, which was completely dredged and reconstructed. Samples were taken monthly (2006–2009) at five stations. The total rotifer abundance exponentially declined and reached a relatively stable stage in 2009. Polyarthra dolichoptera and Trichocerca pusilla dominated the rotifer community in most seasons. TN, TP, and CODMn went down at the beginning of the monitoring period, rebounded in the second winter, and then decreased and reached a stable state in 2009. CCA showed that the most significant variations were caused by fluctuations in temperature, CODMn, SRP, and NO2-N. The rotifer community experienced a two-stage succession and the difference of species between the stages was exhibited during warm seasons. GAMs indicated that the selected factors were responsible for 64.8% of the total rotifer abundance variance and 16.5~64.3% of the variances of individual species abundance. Most of the environmental parameters had effects on rotifer abundance that could only be described by complicated curves, characterised by unimodality and bimodality instead of linearity. Our study highlighted the temperature influence on rotifer species composition and total abundance in subtropical lakes. PMID:23864829

  13. Actin phylogeny identifies Mesostigma viride as a flagellate ancestor of the land plants.

    PubMed

    Bhattacharya, D; Weber, K; An, S S; Berning-Koch, W

    1998-11-01

    Green algae and land plants trace their evolutionary history to a unique common ancestor. This "green lineage" is phylogenetically subdivided into two distinct assemblages, the Chlorophyta and the Streptophyta. The Chlorophyta includes the Chlorophyceae, Trebouxiophyceae, Ulvophyceae, and Prasinopohyceae, whereas the Streptophyta includes the Charophyceae plus the bryophytes, ferns, and all other multicellular land plants (Embryophyta). The Prasinophyceae is believed to contain the earliest divergences within the green lineage. Phylogenetic analyses using rDNA sequences identify the prasinophytes as a paraphyletic taxon that diverges at the base of the Chlorophyta. rDNA analyses, however, provide ambiguous results regarding the identity of the flagellate ancestor of the Streptophyta. We have sequenced the actin-encoding cDNAs from Scherffelia dubia (Prasinophyceae), Coleochaete scutata, Spirogyra sp. (Charophyceae), and the single-copy actin gene from Mesostigma viride (Prasinophyceae). Phylogenetic analyses show Mesostigma to be the earliest divergence within the Streptophyta and provide direct evidence for a scaly, biflagellate, unicellular ancestor for this lineage. This result is supported by the existence of two conserved actin-coding region introns (positions 20-3, 152-1), and one intron in the 5'-untranslated region of the actin gene shared by Mesostigma and the embryophytes.

  14. Study on algae removal by immobilized biosystem on sponge

    NASA Astrophysics Data System (ADS)

    Pei, Haiyan; Hu, Wenrong

    2006-10-01

    In this study, sponges were used to immobilize domesticated sludge microbes in a limited space, forming an immobilized biosystem capable of algae and microcystins removal. The removal effects on algae, microcystins and UV260 of this biosystem and the mechanism of algae removal were studied. The results showed that active sludge from sewage treatment plants was able to remove algae from a eutrophic lake’s water after 7 d of domestication. The removal efficiency for algae, organic matter and microcystins increased when the domesticated sludge was immobilized on sponges. When the hydraulic retention time (HRT) was 5h, the removal rates of algae, microcystins and UV260 were 90%, 94.17% and 84%, respectively. The immobilized biosystem consisted mostly of bacteria, the Ciliata and Sarcodina protozoans and the Rotifer metazoans. Algal decomposition by zoogloea bacteria and preying by microcreatures were the two main modes of algal removal, which occurred in two steps: first, absorption by the zoogloea; second, decomposition by the zoogloea bacteria and the predacity of the microcreatures.

  15. Protistan Bacterivory in an Oligomesotrophic Lake: Importance of Attached Ciliates and Flagellates

    PubMed

    Carrias; Amblard; Bourdier

    1996-05-01

    Seasonal and depth variations of the abundance, biomass, and bacterivory of protozoa (heterotrophic and mixotrophic flagellates and ciliates) were determined during thermal stratification in an oligomesotrophic lake (Lake Pavin, France). Maximal densities of heterotrophic flagellates (1.9x10(3) cells ml-1) and ciliates (6.1 cells ml-1) were found in the metalimnion. Pigmented flagellates dominated the flagellate biomass in the euphotic zone. Community composition of ciliated protists varied greatly with depth, and both the abundance and biomass of ciliates was dominated by oligotrichs. Heterotrophic flagellates dominated grazing, accounting for 84% of total protistan bacterivory. Maximal grazing impact of heterotrophic flagellates was 18.9x10(6) bacteria 1(-1)h-1. On average, 62% of nonpigmented flagellates were found to ingest particles. Ciliates and mixotrophic flagellates averaged 13% and 3% of protistan bacterivory, respectively. Attached protozoa (ciliates and flagellates) were found to colonize the diatom Asterionella formosa. Attached bacterivores had higher ingestion rates than free bacterivorous protozoa and may account for 66% of total protozoa bacterivory. Our results indicated that even in low numbers, epibiotic protozoa may have a major grazing impact on free bacteria.

  16. Control of microfabricated structures powered by flagellated bacteria using phototaxis

    NASA Astrophysics Data System (ADS)

    Steager, Edward; Kim, Chang-Beom; Patel, Jigarkumar; Bith, Socheth; Naik, Chandan; Reber, Lindsay; Kim, Min Jun

    2007-06-01

    Flagellated bacteria have been employed as microactuators in low Reynolds number fluidic environments. SU-8 microstructures have been fabricated and released on the surface of swarming Serratia marcescens, and the flagella propel the structures along the swarm surface. Phototactic control of these structures is demonstrated by exposing the localized regions of the swarm to ultraviolet light. The authors additionally discuss the control of microstructures in an open channel powered by bacteria which have been docked through a blotting technique. A tracking algorithm has been developed to analyze swarming patterns of the bacteria as well as the kinematics of the microstructures.

  17. Cytogenetic evidence for asexual evolution of bdelloid rotifers.

    PubMed

    Mark Welch, Jessica L; Mark Welch, David B; Meselson, Matthew

    2004-02-10

    DNA sequencing has shown individual bdelloid rotifer genomes to contain two or more diverged copies of every gene examined and has revealed no closely similar copies. These and other findings are consistent with long-term asexual evolution of bdelloids. It is not entirely ruled out, however, that bdelloid genomes consist of previously undetected pairs of sequences so similar as to be identical over the regions sequenced, as might result if bdelloids were highly inbred sexual diploids or polyploids. Here, we employ fluorescent in situ hybridization with cosmid probes to determine the copy number and chromosomal distribution of the heat shock gene hsp82 and adjacent sequences in the bdelloid Philodina roseola. We conclude that the four copies identified by sequencing are the only ones present and that each is on a separate chromosome. Bdelloids therefore are not highly homozygous sexually reproducing diploids or polyploids.

  18. Morphological Similarity and Ecological Overlap in Two Rotifer Species

    PubMed Central

    Gabaldón, Carmen; Montero-Pau, Javier; Serra, Manuel; Carmona, María José

    2013-01-01

    Co-occurrence of cryptic species raises theoretically relevant questions regarding their coexistence and ecological similarity. Given their great morphological similitude and close phylogenetic relationship (i.e., niche retention), these species will have similar ecological requirements and are expected to have strong competitive interactions. This raises the problem of finding the mechanisms that may explain the coexistence of cryptic species and challenges the conventional view of coexistence based on niche differentiation. The cryptic species complex of the rotifer Brachionus plicatilis is an excellent model to study these questions and to test hypotheses regarding ecological differentiation. Rotifer species within this complex are filtering zooplankters commonly found inhabiting the same ponds across the Iberian Peninsula and exhibit an extremely similar morphology—some of them being even virtually identical. Here, we explore whether subtle differences in body size and morphology translate into ecological differentiation by comparing two extremely morphologically similar species belonging to this complex: B. plicatilis and B. manjavacas. We focus on three key ecological features related to body size: (1) functional response, expressed by clearance rates; (2) tolerance to starvation, measured by growth and reproduction; and (3) vulnerability to copepod predation, measured by the number of preyed upon neonates. No major differences between B. plicatilis and B. manjavacas were found in the response to these features. Our results demonstrate the existence of a substantial niche overlap, suggesting that the subtle size differences between these two cryptic species are not sufficient to explain their coexistence. This lack of evidence for ecological differentiation in the studied biotic niche features is in agreement with the phylogenetic limiting similarity hypothesis but requires a mechanistic explanation of the coexistence of these species not based on

  19. Water quality and the rotifer populations in the Atchafalaya River Basin, Louisiana

    USGS Publications Warehouse

    Holland, L.E.; Bryan, C.F.; Newman, J.P.

    1983-01-01

    The authors compiled distributional and ecological information on the class Rotifera from both flood controlled and uncontrolled reaches of the Atchafalya River Basin, a large river-swamp in the south-central United States. In the minimally altered lower basin a variety of aquatic habitats within a small area resulted in a very diverse rotifer community consisting of an average of 46 taxa. In contrast, only an average of 28 different taxa were collected in leeved upper basin habitats. As a result of cluster analysis it was possible to identify rotifer communities associated with areas of similar water quality. Variations in suspended solids, total dissolved solids, and organic carbon were most often significantly associated with variations in rotifer numbers from the lower basin. Seasonal flushing of backwater areas by mainstem waters is very important in maintaining the diversity of these lower basin rotifer communities.

  20. Methods for culturing saltwater rotifers (Brachionus plicatilis) for rearing larval zebrafish.

    PubMed

    Lawrence, Christian; Sanders, Erik; Henry, Eric

    2012-09-01

    The saltwater rotifer, Brachionus plicatilis, is widely used in the aquaculture industry as a prey item for first-feeding fishes due to its ease of culture, small size, rapid reproductive rate, and amenability to enrichment with nutrients. Despite the distinct advantages of this approach, rotifers have only been sporadically utilized for rearing larval zebrafish, primarily because of the common misconception that maintaining cultures of rotifers is difficult and excessively time-consuming. Here we present simple methods for maintaining continuous cultures of rotifers capable of supporting even the very largest zebrafish aquaculture facility, with minimal investments in materials, time, labor, and space. Examples of the methods' application in one large, existing facility is provided, and troubleshooting of common problems is discussed.

  1. The process-dependent impacts of dimethoate on the feeding behavior of rotifer.

    PubMed

    Chen, Jianqiu; Guo, Ruixin

    2015-01-01

    Traditional toxicological studies usually depict the dose-effect relationship at the given exposure time while ignore how toxic effects vary during and after the exposure. In the present study, feeding depression of the rotifer Brachionus calyciflorus under the impact of dimethoate was evaluated not only in the exposure time but also in the post-exposure time. Both the filtration rates (F) and the ingestion rates (I) of the rotifers varied during the exposure period under any concentration of dimethoate. A three-stepwise stress was observed when the rotifers were exposed to 0.2 and 1.0 mg L(-1) of the pesticide respectively, whereas 1.8 mg L(-1) dimethoate caused only one-step stress on the rotifers during the whole period. In addition, although the feeding behaviors of the rotifers recovered after the exposure, two feeding rates both got even more depressed at 8h in the post-exposure time. The latent inhibition after exposure was related to the exposure concentrations and the exposure time. Our works indicated that the impact of dimethoate on the feeding behavior of the rotifers was highly process-dependent that caused the stepwise stress during the exposure period and the latent stress after the exposure.

  2. Assessing the impacts of dimethoate on rotifers' reproduction through the pre-exposure history.

    PubMed

    Guo, Ruixin; Chen, Jianqiu

    2015-01-01

    Organism usually undergoes an exposure of environmental pollution after a maternal exposure before birth. Traditional toxicological studies often initiated with rotifer neonates derived from the unexposed mothers while ignoring the pre-exposure (maternal exposure). The present study assessed the effect of dimethoate on the reproduction of the rotifer Brachionus calyciflorus, considering how the pre-exposure occurred in the parental generation influenced the subsequent impact. The F0 generation rotifers were exposed to the pesticide at five concentrations until the first F1 generation rotifers were reproduced. The neonates (F1 generation) were then exposed to the pesticide at the corresponding concentrations. The offspring reproduction, the time begins to reproduce, the duration of the reproductive period and the lifespan of the F1 generation rotifers were evaluated. Our results indicated that dimethoate influenced the maturation and reproduction of the rotifers. The highest concentration (1.8 mg L(-1)) of dimethoate caused an inhibition in the offspring reproduction, shortened the life span and reduced the duration of the reproductive period. In addition, of particular interest in our study was that reproduction is also accelerated by the lowest concentration (0.2 mg L(-1)). However, the pre-exposure had a significant effect on the subsequent impact. The dimethoate pre-exposure increased the impacts when the F1 generation rotifers were exposed to the substance, even at the same concentrations as in pre-exposure. It suggests that the maternal exposure history before birth is also important and has the long-lasting consequence from one generation to another.

  3. The use of turbidostat culture in investigation of algal heavy-metal toxicity and rotifer population dynamics

    SciTech Connect

    Bennett, W.N.

    1989-01-01

    Using the green alga Chlorella pyrenoidosa Chick, the heavy metals selenium as selenate, cadmium, cadmium + manganese and cadmium + zinc were investigated to assess their toxicity in terms of changes in {mu}{sub max}. It was shown that increases of sublethal concentrations of Se produced a near linear decrease in {mu}{sub max}. A {mu}{sub max}IC{sub 50} was calculated to be 10.1 {mu}M Se. A concentration of 1.8 {mu}M Cd produced a 62% decrease in {mu}{sub max} after 2 generating lag. A recovery of {mu}{sub max} was observed when MnCl{sub 2} or ZnCl{sub 2} was added to the medium in which populations were experiencing sublethal Cd toxicity. The amelioration responses were incomplete with regard to full recovery of {mu}{sub max} and last 20 generations for the Cd-Mn exposure and 7 generations for the Cd-Zn exposure. Measurement of {mu}{sub max} is turbidostat culture was shown to provide a very sensitive measure of toxicity. For the first time, a metazoan, the rotifer Brachionus calyciflorus Pallas, was grown in turbidostat culture and maintained near its {mu}{sub max} for many generations. It was discovered that {mu}{sub max} was subject to selection in this species and increased 51% from 0.053 h{sup {minus}1} to 0.080 h{sup {minus}1} over 8 mo at 25{degree}C.

  4. Flagellation of Pseudomonas aeruginosa in newly divided cells

    NASA Astrophysics Data System (ADS)

    Zhao, Kun; Lee, Calvin; Anda, Jaime; Wong, Gerard

    2015-03-01

    For monotrichous bacteria, Pseudomonas aeruginosa, after cell division, one daughter cell inherits the old flagellum from its mother cell, and the other grows a new flagellum during or after cell division. It had been shown that the new flagellum grows at the distal pole of the dividing cell when the two daughter cells haven't completely separated. However, for those daughter cells who grow new flagella after division, it still remains unknown at which pole the new flagellum will grow. Here, by combining our newly developed bacteria family tree tracking techniques with genetic manipulation method, we showed that for the daughter cell who did not inherit the old flagellum, a new flagellum has about 90% chances to grow at the newly formed pole. We proposed a model for flagellation of P. aeruginosa.

  5. Responses of the photosynthetic flagellate, Euglena gracilis, to microgravity.

    PubMed

    Hader, D P; Vogel, K; Schafer, J

    1990-09-01

    Motility and orientation have been studied in the unicellular photosynthetic flagellate. Euglena gracilis, using real time image analysis capable of tracking up to 200 cells simultaneously before, during and after a sounding rocket (TEXUS) experiment. The cells orient negative gravitactically under 1 g conditions and the degree of orientation increases with time when kept in a closed system. Under micro-g conditions the cells orient randomly and display no cooperativity between the individuals. Under 1 g conditions the velocity, which has been determined simultaneously to the orientation vectors, depends on the direction of swimming with respect to the gravity vector. Under micro-g conditions the cells swim significantly faster. After retrieval of the rocket the cells returned to normal gravitaxis and motility as observed before the space flight.

  6. Pankinetoplast DNA structure in a primitive bodonid flagellate, Cryptobia helicis.

    PubMed Central

    Lukescaron, J; Jirkû, M; Avliyakulov, N; Benada, O

    1998-01-01

    The mitochondrial DNA (mtDNA) of a primitive kinetoplastid flagellate Cryptobia helicis is composed of 4.2 kb minicircles and 43 kb maxicircles. 85% and 6% of the minicircles are in the form of supercoiled (SC) and relaxed (OC) monomers, respectively. The remaining minicircles (9%) constitute catenated oligomers composed of both the SC and OC molecules. Minicircles contain bent helix and sequences homologous to the minicircle conserved sequence blocks. Maxicircles encode typical mitochondrial genes and are not catenated. The mtDNA, which we describe with the term 'pankinetoplast DNA', is spread throughout the mitochondrial lumen, where it is associated with multiple electron-lucent loci. There are approximately 8400 minicircles per pankinetoplast-mitochondrion, with the pan-kDNA representing approximately 36% of the total cellular DNA. Based on the similarity of the C.helicis minicircles to plasmids, we present a theory on the formation of the kDNA network. PMID:9451008

  7. Telonema antarcticum sp. nov., a common marine phagotrophic flagellate.

    PubMed

    Klaveness, Dag; Shalchian-Tabrizi, Kamran; Thomsen, Helge Abildhauge; Eikrem, Wenche; Jakobsen, Kjetill S

    2005-11-01

    Telonema is a widely distributed group of phagotrophic flagellates with two known members. In this study, the structural identity and molecular phylogeny of Telonema antarcticum was investigated and a valid description is proposed. Molecular phylogeny was studied using small-subunit rRNA (SSU rRNA) gene sequences. The pear-shaped cell had two subequal flagella that emerged laterally on the truncated antapical tail. One flagellum had tripartite hairs. The cell was naked, but had subsurface vesicles containing angular paracrystalline bodies of an unknown nature. A unique complex cytoskeletal structure, the subcortical lamina, was found to be an important functional and taxonomic feature of the genus. Telonema has an antero-ventral depression where food particles are ingested and then transferred to a conspicuous anterior food vacuole. The molecular phylogeny inferred from the SSU rRNA gene sequence suggested that Telonema represents an isolated and deep branch among the tubulocristate protists.

  8. Evolutionary relationships among "jakobid" flagellates as indicated by alpha- and beta-tubulin phylogenies.

    PubMed

    Edgcomb, V P; Roger, A J; Simpson, A G; Kysela, D T; Sogin, M L

    2001-04-01

    Jakobids are free-living, heterotrophic flagellates that might represent early-diverging mitochondrial protists. They share ultrastructural similarities with eukaryotes that occupy basal positions in molecular phylogenies, and their mitochondrial genome architecture is eubacterial-like, suggesting a close affinity with the ancestral alpha-proteobacterial symbiont that gave rise to mitochondria and hydrogenosomes. To elucidate relationships among jakobids and other early-diverging eukaryotic lineages, we characterized alpha- and beta-tubulin genes from four jakobids: Jakoba libera, Jakoba incarcerata, Reclinomonas americana (the "core jakobids"), and Malawimonas jakobiformis. These are the first reports of nuclear genes from these organisms. Phylogenies based on alpha-, beta-, and combined alpha- plus beta-tubulin protein data sets do not support the monophyly of the jakobids. While beta-tubulin and combined alpha- plus beta-tubulin phylogenies showed a sister group relationship between J. libera and R. americana, the two other jakobids, M. jakobiformis and J. incarcerata, had unclear affinities. In all three analyses, J. libera, R. americana, and M. jakobiformis emerged from within a well-supported large "plant-protist" clade that included plants, green algae, cryptophytes, stramenopiles, alveolates, Euglenozoa, Heterolobosea, and several other protist groups, but not animals, fungi, microsporidia, parabasalids, or diplomonads. A preferred branching order within the plant-protist clade was not identified, but there was a tendency for the J. libera-R. americana lineage to group with a clade made up of the heteroloboseid amoeboflagellates and euglenozoan protists. Jakoba incarcerata branched within the plant-protist clade in the beta- and the combined alpha- plus beta-tubulin phylogenies. In alpha- tubulin trees, J. incarcerata occupied an unresolved position, weakly grouping with the animal/fungal/microsporidian group or with amitochondriate parabasalid and

  9. Enhancement of flagellated bacterial motility in polymer solutions

    NASA Astrophysics Data System (ADS)

    Zhang, Wenyu; Sha, Sha; Pelcovits, Robert; Tang, Jay

    2015-11-01

    Measurements of the swimming speed of many species of flagellated bacteria in polymer solutions have shown that with the addition of high molecular weight polymers, the speed initially increases as a function of the kinematic viscosity. It peaks at around 1.5-2 cP with typically 10-30% higher values than in cell media without added polymers (~ 1 cP). Past the peak, the average speed gradually decreases as the solution becomes more viscous. Swimming motility persists until solution viscosity reaches 5-10 cP. Models have been proposed to account for this behavior, and the magnitude of the peak becomes a crucial test of theoretical predictions. The status of the field is complicated in light of a recent report (Martinez et al., PNAS, 2014), stressing that low-molecular weight impurities account for the peaked speed-viscosity curves in some cases. We measured the swimming speed of a uni-flagellated bacterium, caulobacter crescentus, in solutions of a number of polymers of several different sizes. Our findings confirm the peaked speed-viscosity curve, only as the molecular weight of the flexible polymers used surpassed ~ 50,000 da. The threshold molecular weight required to augment swimming speed varies somewhat with the polymer species, but it generally corresponds to radius of gyration over tens of nanometers. This general feature is consistent with the model of Powers et al. (Physics of Fluid, 2009), predicting that nonlinear viscoelasticity of the fluid enhances swimming motility. Work Supported by the NSF Fluid Physics Program (Award number CBET 1438033).

  10. Genome structure of bdelloid rotifers: shaped by asexuality or desiccation?

    PubMed

    Gladyshev, Eugene A; Arkhipova, Irina R

    2010-01-01

    Bdelloid rotifers are microscopic invertebrate animals best known for their ancient asexuality and the ability to survive desiccation at any life stage. Both factors are expected to have a profound influence on their genome structure. Recent molecular studies demonstrated that, although the gene-rich regions of bdelloid genomes are organized as colinear pairs of closely related sequences and depleted in repetitive DNA, subtelomeric regions harbor diverse transposable elements and horizontally acquired genes of foreign origin. Although asexuality is expected to result in depletion of deleterious transposons, only desiccation appears to have the power to produce all the uncovered genomic peculiarities. Repair of desiccation-induced DNA damage would require the presence of a homologous template, maintaining colinear pairs in gene-rich regions and selecting against insertion of repetitive DNA that might cause chromosomal rearrangements. Desiccation may also induce a transient state of competence in recovering animals, allowing them to acquire environmental DNA. Even if bdelloids engage in rare or obscure forms of sexual reproduction, all these features could still be present. The relative contribution of asexuality and desiccation to genome organization may be clarified by analyzing whole-genome sequences and comparing foreign gene and transposon content in species which lost the ability to survive desiccation.

  11. Zooplankton competition promotes trade-offs affecting diapause in rotifers.

    PubMed

    Aránguiz-Acuña, Adriana; Ramos-Jiliberto, Rodrigo; Serra, Manuel

    2015-01-01

    Facultative diapause should be favoured by natural selection in temporary variable habitats. Diapause patterns are evolutionary constrained because producing diapause is resource demanding, which might have implications for competitive dynamics and competitor coexistence through mechanisms such as the storage effect. Besides these implications, competition intensity might affect the quality of the diapausing stages and the reproductive success of the offspring emerging from them. We experimentally analysed traits involved in diapause in the cyclically parthenogenetic rotifer Brachionus calyciflorus, in relation to the presence of its competitor, the cladoceran Moina micrura. Under competition with Moina, Brachionus produced fewer diapausing eggs, most of which possessed visual attributes indicating a higher quality. These diapausing eggs produced under a competitive environment had a higher hatching success; however, the hatchlings exhibited a lower population growth rate. We propose the existence of trade-offs between traits related to diapause: the number of produced eggs, quality of these eggs and hatchling performance. Our results show that interspecific competition may cause fine-tuned changes in the life cycle patterns of the populations. Furthermore, these changes could affect that abundance and performance of competitors and thereby drive back effects on the competitive output. These diapause-driven feedback mechanisms may have strong implications for the dynamics of the natural communities. PMID:25464990

  12. Zooplankton competition promotes trade-offs affecting diapause in rotifers.

    PubMed

    Aránguiz-Acuña, Adriana; Ramos-Jiliberto, Rodrigo; Serra, Manuel

    2015-01-01

    Facultative diapause should be favoured by natural selection in temporary variable habitats. Diapause patterns are evolutionary constrained because producing diapause is resource demanding, which might have implications for competitive dynamics and competitor coexistence through mechanisms such as the storage effect. Besides these implications, competition intensity might affect the quality of the diapausing stages and the reproductive success of the offspring emerging from them. We experimentally analysed traits involved in diapause in the cyclically parthenogenetic rotifer Brachionus calyciflorus, in relation to the presence of its competitor, the cladoceran Moina micrura. Under competition with Moina, Brachionus produced fewer diapausing eggs, most of which possessed visual attributes indicating a higher quality. These diapausing eggs produced under a competitive environment had a higher hatching success; however, the hatchlings exhibited a lower population growth rate. We propose the existence of trade-offs between traits related to diapause: the number of produced eggs, quality of these eggs and hatchling performance. Our results show that interspecific competition may cause fine-tuned changes in the life cycle patterns of the populations. Furthermore, these changes could affect that abundance and performance of competitors and thereby drive back effects on the competitive output. These diapause-driven feedback mechanisms may have strong implications for the dynamics of the natural communities.

  13. Characterization of proteins in flagellates and growing amebae of Naegleria fowleri.

    PubMed

    Woodworth, T W; Keefe, W E; Bradley, S G

    1982-06-01

    Polypeptides of whole-cell extracts of Naegleria fowleri flagellates and growing amebae were resolved by two-dimensional polyacrylamide gel electrophoresis. Autoradiograms of the [35S]methionine-labeled polypeptides of amebae and flagellates were analyzed by two dimensional densitometry to determine whether there were correlations between intracellular concentration of a protein and subunit size or charge. The majority of the polypeptides of amebae and flagellates had molecular sizes in the range of 20 to 60 kilodaltons. The radioactivity per polypeptide species in the size range of 20 to 60 kilodaltons was greater in amebae than in flagellates. The greatest number of polypeptides detected in amebae and flagellates was in the isoelectric focusing range of pH 6 to 7. The radioactivity per polypeptide species in the isoelectric focusing gradient below 6.3 was greater in amebae than in flagellates. Polypeptides in the size range of 20 to 60 kilodaltons had a median isoelectric point below pI 6.3, whereas those larger than 60 kilodaltons had a median pI value above 6.3. These data indicated that molecular size and charge were not entirely independent variables and that the size and charge of a polypeptide might have an important influence in determining its intracellular concentration in both amebae and flagellates. Autoradiograms were also compared so that changes in intracellular protein complement and concentrations occurring during differentiation could be recognized. The relative amounts of a limited number of polypeptides increased markedly, and others decreased markedly, during enflagellation.

  14. The Complete and Updated "Rotifer Polyculture Method" for Rearing First Feeding Zebrafish.

    PubMed

    Lawrence, Christian; Best, Jason; Cockington, Jason; Henry, Eric C; Hurley, Shane; James, Althea; Lapointe, Christopher; Maloney, Kara; Sanders, Erik

    2016-01-01

    The zebrafish (Danio rerio) is a model organism of increasing importance in many fields of science. One of the most demanding technical aspects of culture of this species in the laboratory is rearing first-feeding larvae to the juvenile stage with high rates of growth and survival. The central management challenge of this developmental period revolves around delivering highly nutritious feed items to the fish on a nearly continuous basis without compromising water quality. Because larval zebrafish are well-adapted to feed on small zooplankton in the water column, live prey items such as brachionid rotifers, Artemia, and Paramecium are widely recognized as the feeds of choice, at least until the fish reach the juvenile stage and are able to efficiently feed on processed diets. This protocol describes a method whereby newly hatched zebrafish larvae are cultured together with live saltwater rotifers (Brachionus plicatilis) in the same system. This polyculture approach provides fish with an "on-demand", nutrient-rich live food source without producing chemical waste at levels that would otherwise limit performance. Importantly, because the system harnesses both the natural high productivity of the rotifers and the behavioral preferences of the fish, the labor involved with maintenance is low. The following protocol details an updated, step-by-step procedure that incorporates rotifer production (scalable to any desired level) for use in a polyculture of zebrafish larvae and rotifers that promotes maximal performance during the first 5 days of exogenous feeding. PMID:26863035

  15. Transformation of a rotifer community in runoff of the Ucha reservoir and carrier canal

    SciTech Connect

    Lebedeva, L.I.; Kartasheva, N.V.; Vorozhun, I.M.

    1985-11-01

    The purpose of the work was to study the long-term seasonal dynamics of the runoff of rotifers of the Ulcha reservoir in the carrier channel, and to investigate the regularities of the change in the species composition and number of rotifers in the carrier channel. Substantial changes occur in the composition of the rotifer community as the water advances along the canal route. In the first stretch of the canal the number of A. priodonta and F. longiseta and in the closed stretch the number of C. inicornis and S. pectinata decrease markedly. The most stable to the flow were B. calyciflorus, K. quadrata, and K. cochlearis. By the end of the canal, after chlorination and settling in the bucket, the composition of the rotifers is extremely poor both qualitatively and quantitatively. No more than 4-10% of the initial number of rotifers in the runoff remains in the water flowing from the bucket to the treatment plants, and in a species respect K. quadrata and B. calyciflorous dominate, and therefore outbreaks of these species should be controlled attentively.

  16. A Rotifer-Based Technique to Rear Zebrafish Larvae in Small Academic Settings.

    PubMed

    Allen, Raymond L; Wallace, Robert L; Sisson, Barbara E

    2016-08-01

    Raising zebrafish from larvae to juveniles can be laborious, requiring frequent water exchanges and continuous culturing of live feed. This task becomes even more difficult for small institutions that do not have access to the necessary funding, equipment, or personnel to maintain large-scale systems usually employed in zebrafish husbandry. To open this opportunity to smaller institutions, a cost-efficient protocol was developed to culture Nannochloropsis to feed the halophilic, planktonic rotifer Brachionus plicatilis; the rotifers were then used to raise larval zebrafish to juveniles. By using these methods, small institutions can easily raise zebrafish embryos in a cost-efficient manner without the need to establish an extensive fish-raising facility. In addition, culturing rotifers provides a micrometazoan that serves as a model organism for teaching and undergraduate research studies for a variety of topics, including aging, toxicology, and predator-prey dynamics. PMID:26886557

  17. A Novel Method for Rearing Zebrafish by Using Freshwater Rotifers (Brachionus calyciflorus).

    PubMed

    Aoyama, Yuta; Moriya, Natsumi; Tanaka, Shingo; Taniguchi, Tomoko; Hosokawa, Hiroshi; Maegawa, Shingo

    2015-08-01

    The zebrafish (Danio rerio) has become a powerful model organism for studying developmental processes and genetic diseases. However, there remain several problems in previous rearing methods. In this study, we demonstrate a novel method for rearing zebrafish larvae by using a new first food, freshwater rotifers (Brachionus calyciflorus). Feeding experiments indicated that freshwater rotifers are suitable as the first food for newly hatched larval fish. In addition, we revisited and improved a feeding schedule from 5 to 40 days postfertilization. Our feeding method using freshwater rotifers accelerated larval growth. At 49 dpf, one pair out of 10 pairs successfully produced six fertilized eggs. At 56, 63, and 71 dpf, 6 out of the 10 pairs constantly produced normal embryos. Our method will improve the husbandry of the zebrafish.

  18. A Novel Method for Rearing Zebrafish by Using Freshwater Rotifers (Brachionus calyciflorus)

    PubMed Central

    Aoyama, Yuta; Moriya, Natsumi; Tanaka, Shingo; Taniguchi, Tomoko; Hosokawa, Hiroshi

    2015-01-01

    Abstract The zebrafish (Danio rerio) has become a powerful model organism for studying developmental processes and genetic diseases. However, there remain several problems in previous rearing methods. In this study, we demonstrate a novel method for rearing zebrafish larvae by using a new first food, freshwater rotifers (Brachionus calyciflorus). Feeding experiments indicated that freshwater rotifers are suitable as the first food for newly hatched larval fish. In addition, we revisited and improved a feeding schedule from 5 to 40 days postfertilization. Our feeding method using freshwater rotifers accelerated larval growth. At 49 dpf, one pair out of 10 pairs successfully produced six fertilized eggs. At 56, 63, and 71 dpf, 6 out of the 10 pairs constantly produced normal embryos. Our method will improve the husbandry of the zebrafish. PMID:25938499

  19. Bioconcentration and localization of lead in the freshwater rotifer Brachionus calyciflorus Pallas 1677 (Rotifera: Monogononta).

    PubMed

    Alvarado-Flores, Jesús; Rico-Martínez, Roberto; Ventura-Juárez, Javier; Silva-Briano, Marcelo; Rubio-Franchini, Isidoro

    2012-03-01

    We studied how lead is bioconcentrated and distributed in the rotifer Brachionus calyciflorus using metal histochemistry to locate lead granules, Leadmium Green® analysis to establish the route of uptake, atomic absorption to determined the bioconcentration factor (BCF), and detected the presence of microelements in the cuticle by X-ray microanalysis with scanning electron microscopy. Our results indicate: (a) the digestive system is the main route of lead uptake in the rotifer B. calyciflorus, (b) after 24-h lead is deposited in granules in the mastax and vitellarium, (c) our energy-dispersive X-ray microanalysis indicates decalcification taking place in the cuticle of the rotifer after a 24-h lead exposure, and (d) we determined a BCF = 115 for lead after a 24 h exposure. However, the route of mobilization and storage of intracellular lead are still not fully understood in B. calyciflorus.

  20. Estimating the toxicity of ambient fine aerosols using freshwater rotifer Brachionus calyciflorus (Rotifera: Monogononta).

    PubMed

    Verma, Vishal; Rico-Martinez, Roberto; Kotra, Neel; Rennolds, Corey; Liu, Jiumeng; Snell, Terry W; Weber, Rodney J

    2013-11-01

    The toxicity of atmospheric fine particulate matter (PM2.5) in Atlanta is assessed using freshwater rotifers (Brachionus calyciflorus). The PM-laden quartz filters were extracted in both water and methanol. Aerosol extracts were passed through a C-18 column to separate the PM components into hydrophobic and hydrophilic fractions. Toxicity data reported in the units of LC50 (concentration that kills 50% of the test population in 24 h) shows that ambient particles are toxic to the rotifers with LC50 values ranging from 5 to 400 μg of PM. The methanol extract of the aerosols was substantially more toxic (8 ± 6 times) to the rotifers compared to the water extracts. A sizeable fraction (>70%) of toxicity was found to be associated with the hydrophobic fraction of PM. However, none of the bulk aerosol species was strongly correlated with the LC50 values suggesting a complicated mechanism of toxicity probably involving synergistic interactions of various PM components.

  1. Adverse effects and bioconcentration of chromium in two freshwater rotifer species.

    PubMed

    Hernández-Ruiz, Esmeralda; Alvarado-Flores, Jesús; Rubio-Franchini, Isidoro; Ventura-Juárez, Javier; Rico-Martínez, Roberto

    2016-09-01

    Bioaccumulation of trivalent (CrIII) and hexavalent chromium (CrVI), and its adverse effects were studied in two rotifer species: Brachionus calyciflorus (two different strains), and Lecane quadridentata. Median Lethal Concentration (LC50) at 24 h of both species showed that CrVI is highly toxic: LC50 ranges from 4.7 × 10(-5) to 4 × 10(-6) mg L(-1)), compared with CrIII: LC50 ranges from 0.64 to 1.279 mg L(-1). Using the LC50 as an exposure concentration, and using atomic absorption, the bioconcentration factor (BCF) was obtained and BCFs of rotifers exposed to CrIII are four orders of magnitude lower than BCFs of rotifers exposed to CrVI. The effect of Cr on the elemental composition of the two species of rotifers in their structures by X-ray microanalysis by energy dispersion showed that Cr is found in intoxicated rotifers, but not in control rotifers. The basal immunoreactivity to metallothioneins is greater in B. calyciflorus than L. quadridentata. The immunoreactivity to metallothioneins decreases in B. calyciflorus when is exposed to CrIII, in contrast in L. quadridentata the immunoreactivity to metallothioneins increase when is exposed to CrIII, and the immunoreactivity to CrVI in L. quadridentata decrease. A mechanism is proposed in which the harder lorica of L. quadridentata acts as a barrier and accumulator of CrVI, and allows for attenuating responses like metallothionein production in L. quadridentata. Instead, in B. calyciflorus the lack of a harder lorica allows for deeper penetration of CrVI, and no time to produce attenuating measures. PMID:27258901

  2. Toxicity of triphenyltin chloride to the rotifer Brachionus koreanus across different levels of biological organization.

    PubMed

    Yi, Andy Xianliang; Han, Jeonghoon; Lee, Jae-Seong; Leung, Kenneth M Y

    2016-01-01

    Although triphenyltin (TPT) compounds are ubiquitous pollutants in urbanised coastal environments in Asian regions, their toxicities to marine organisms are still poorly known. This study was designed to investigate the toxicity of triphenyltin chloride (TPTCl) on the rotifer Brachionus koreanus across different levels of biological organisation. Firstly, we concurrently performed a 24 h static-acute toxicity test and a 6-day semi-static multigenerational life-cycle test using the rotifer. Our results demonstrated that the 24-h median lethal concentration of TPTCl for the rotifer was 29.6 μg/L and the 6-day median effect concentration, based on the population growth inhibition, was 3.31 μg/L. Secondly, we examined the expression of 12 heat shock protein (hsp) genes, four glutathione S-transferase (GST) genes, one retinoid X receptor (RXR) gene and 13 cytochrome P450 (CYP) genes in the rotifers after exposure to 20 µg/L TPTCl for 24 h. Among these studied genes, hsp90α2, GST-O and CYP3045C1 were the most significantly up-regulated genes with a relative expression level up to 32.9, 4.4 and 62.6 folds, respectively. The expression of these three genes in the rotifers showed an increasing trend in the first few hours of TPTCl exposure, peaked at 3 h (hsp90α2 and GST-O) and 12 h (CYP3045C1) respectively, and then gradually returned to a lower level at 24 h. Such up-regulations of hsp and GST genes probably offer cellular protection against the TPT-mediated oxidative stress while the accelerated induction of CYP genes possibly facilitates the detoxification of this toxicant in the rotifer.

  3. Adverse effects and bioconcentration of chromium in two freshwater rotifer species.

    PubMed

    Hernández-Ruiz, Esmeralda; Alvarado-Flores, Jesús; Rubio-Franchini, Isidoro; Ventura-Juárez, Javier; Rico-Martínez, Roberto

    2016-09-01

    Bioaccumulation of trivalent (CrIII) and hexavalent chromium (CrVI), and its adverse effects were studied in two rotifer species: Brachionus calyciflorus (two different strains), and Lecane quadridentata. Median Lethal Concentration (LC50) at 24 h of both species showed that CrVI is highly toxic: LC50 ranges from 4.7 × 10(-5) to 4 × 10(-6) mg L(-1)), compared with CrIII: LC50 ranges from 0.64 to 1.279 mg L(-1). Using the LC50 as an exposure concentration, and using atomic absorption, the bioconcentration factor (BCF) was obtained and BCFs of rotifers exposed to CrIII are four orders of magnitude lower than BCFs of rotifers exposed to CrVI. The effect of Cr on the elemental composition of the two species of rotifers in their structures by X-ray microanalysis by energy dispersion showed that Cr is found in intoxicated rotifers, but not in control rotifers. The basal immunoreactivity to metallothioneins is greater in B. calyciflorus than L. quadridentata. The immunoreactivity to metallothioneins decreases in B. calyciflorus when is exposed to CrIII, in contrast in L. quadridentata the immunoreactivity to metallothioneins increase when is exposed to CrIII, and the immunoreactivity to CrVI in L. quadridentata decrease. A mechanism is proposed in which the harder lorica of L. quadridentata acts as a barrier and accumulator of CrVI, and allows for attenuating responses like metallothionein production in L. quadridentata. Instead, in B. calyciflorus the lack of a harder lorica allows for deeper penetration of CrVI, and no time to produce attenuating measures.

  4. Rotifers from selected inland saline waters in the Chihuahuan Desert of México

    PubMed Central

    Walsh, Elizabeth J; Schröder, Thomas; Wallace, Robert L; Ríos-Arana, Judith V; Rico-Martínez, Roberto

    2008-01-01

    Background In spite of considerable efforts over past decades we still know relatively little regarding the biogeography of rotifers of inland waters in México. To help rectify this we undertook an extensive survey of the rotifer fauna of 48 water bodies in the Chihuahuan Desert of México. Results Of the sites surveyed, 21 had salinities ≥ 2000 μS cm-1 and in these we found 57 species of monogonont rotifers and several bdelloids. Species richness in the saline sites varied widely, with a range in species richness of 1 to 27 and a mean (± 1SD) = 8.8 (± 6.2). Collectively all sites possess relatively high percent single- and doubletons, 33.3 and 21.7%, respectively. Simpson's Asymmetric Index indicated that similarity in rotifer species composition varied widely among a set of 10 sites. These were selected because they were sampled more frequently or represent unusual habitats. These SAI values ranged from 0.00 (complete dissimilarity) to 1.00 (complete similarity). The Jaccard Index varied between 0.00 and 0.35. This observation probably reflects similarities and differences in water chemistry among these sites. Inland saline systems differed in their chemical composition by region. Conductivity was related to hardness and alkalinity. In addition, hardness was positively associated with chloride and sulfate. RDA showed that several species were positively associated with chloride concentration. Other factors that were significantly associated with rotifer species included the presence of macrophytes, nitrate content, oxygen concentration, TDS, latitude and whether the habitat was a large lake or reservoir. Conclusion This study illustrates the diversity of the rotiferan fauna of inland saline systems and the uniqueness among waterbodies. Conservation of these systems is needed to preserve these unique sources of biodiversity that include rotifers and the other endemic species found in association with them. PMID:18533042

  5. [Eye witnesses and the flagellants in the year 1349].

    PubMed

    Jansen-Sieben, R

    1999-01-01

    Deeply affected and often desperately afraid, many contemporaries recorded their observations and emotions. These reports--no matter how obviously subjective they sometimes were--provide valuable information about what happened during the plague pandemic of 1348-1350. Thus many of our fellow countrymen left behind a direct testimony: Bartholomew of Bruges, a canon in Andenne; Gilles li Muisis, the abbot of Saint Martin in Tournai; Ludovicus Sanctus of Beringen; Simon de Couvin, a canon in Liège; Jan van Boendale, an alderman's clerk in Antwerp; John of Burgundy (also known as John of Mandeville), professor of medicine in Liège; but also texts in Middle Dutch that were not known up to now, and therefore not published, such as the important thesis by Arent Schryver, licentiate in medicine (see next article); an account in verse in the Brabant Chronicle, as well as contemporary testimonies in a different language that have been translated into our language, such as that by John of Eschinden, Johannes de Rupescissa or Guy de Chauliac (who had had the plague himself). They describe the precautions, the causes (God, a comet, an eclipse of the sun, the polluted water, the planets, the air), the symptoms, the social groups most likely to be affected (the youth, the lower classes, the clergy), the high mortality, the problems of hygiene,the social and administrative chaos, the general panic, the flight of countless people. One of the most virulent reactions led to the emergence of the flagellant sect. They originated from Hungary and advanced in an unstoppable advance with a growing number of followers as far as our country, singing, praying, dancing and flaying themselves until they drew blood. We only recently discovered what they sang in Dutch: very recently, a unique roll of parchment was discovered that they carried in their processions, and that contains the text of their songs and a flagellant sermon. The existence of this valuable document and its contents are

  6. Effect of flagellates on free-living bacterial abundance in an organically contaminated aquifer.

    PubMed

    Kinner, N E; Harvey, R W; Kazmierkiewicz-Tabaka, M

    1997-07-01

    Little is known about the role of protists in the saturated subsurface. Porous media microcosms, containing bacteria and protists, were used to determine whether flagellates from an organically contaminated aquifer could substantively affect the number of free-living bacteria (FLB). When flagellates were present, the 3-40% maximum breakthrough of fluorescently labelled FLB injected into the microcosms was much lower than the 60-130% observed for killed controls. Grazing and clearance rates (3-27 FLB flag-1 h-1 and 12-23 nl flag-1 h-1, respectively) calculated from the data were in the range reported for flagellates in other aqueous environments. The data provide evidence that flagellate bacterivory is an important control on groundwater FLB populations.

  7. Effect of flagellates on free-living bacterial abundance in an organically contaminated aquifer

    USGS Publications Warehouse

    Kinner, N.E.; Harvey, R.W.; Kazmierkiewicz-Tabaka, M.

    1997-01-01

    Little is known about the role of protists in the saturated subsurface. Porous media microcosms containing bacteria and protists, were used to determine whether flagellates from an organically contaminated aquifer could substantively affect the number of free- living bacteria (FLB). When flagellates were present, the 3-40% maximum breakthrough of fluorescent y labelled FLB injected into the microcosms was much lower than the 60-130% observed for killed controls Grazing and clearance rates (3-27 FLB flag-1 h-1 and 12-23 nI flag-1 h-1, respectively) calculated from the data were in the range reported for flagellates in other aqueous environments. The data provide evidence that flagellate bacterivory is an important control on groundwater FLB populations.

  8. Bleomycin-induced Flagellate Erythema: A Rare and Unique Drug Rash.

    PubMed

    Changal, K H; Raina, H; Changal, Q H; Raina, M

    2014-12-01

    Bleomycin-induced flagellate erythema is a rare rash associated with the use of the drug. The rash has a characteristic and intermingled lacy appearance as if it has been whipped. Lack of detoxifying enzymes for bleomycin in the skin makes it a vulnerable site for the adverse effects of bleomycin, along with the lungs. We report the case of young girl with germ cell tumour who developed bleomycin-induced flagellate erythema. PMID:25867573

  9. Coordinated Swimming: Hydrodynamic interactions between multi-flagellated bacteria

    NASA Astrophysics Data System (ADS)

    Watari, Nobuhiko; Larson, Ronald

    2011-03-01

    Multi-flagellated bacteria, such as Escherichia coli, often have flagella attached at random locations to the cell body, which drive swimming behavior. To study the effect of hydrodynamic interactions on the swimming behavior, we develop a bead-spring model which represents both the body and the flagella using up to 240 Stokeslets, or hydrodynamic drag centers. These beads are bonded by 1) a spring potential, 2) a bending potential, and 3) a torsional potential to adjacent beads. This modeled bacterium swims by rotating the flagella with constant torques. We find that the number and arrangement of the flagella along the bodies of the swimmers affects how two such swimmers approach each other, when swimming either in a line, or side by side, and affects whether or not flagellar rotations are synchronized or not. We show how the flow field generated by each swimmer can be represented using a low order multipole expansion, which can capture the qualitative features of their interactions. With this simple low order expansion, simulations of hundreds or thousands of such swimmers can be carried out, allowing the effects of numbers and locations of flagella on swimming pattern formation to be captured.

  10. Heterotrophic flagellates in the littoral and sublittoral zones of the southeast part of the Pechora Sea

    NASA Astrophysics Data System (ADS)

    Mazei, Yu. A.; Tikhonenkov, D. V.

    2006-05-01

    For the first time, data on the heterotrophic flagellate fauna in the littoral and the sublittoral zones of the southeastern part of the Pechora Sea were obtained. Sixty-six heterotrophic flagellate species were found in the study region: 48 and 42 species were found on the shelf and in the intertidal zone, respectively. The most common species were Cafeteria roenbergensis, Paraphysomonas sp., Ancyromonas sigmoides, Cafeteria minuta, Actinomonas mirabilis, and Spumella sp. The littoral fauna of the heterotrophic flagellates was more peculiar than the sublittoral fauna and equally rich. In the region studied, the community can be divided into two types: (a) the predominantly littoral community characterized by a special composition of the dominant species and by high similarity between its local varieties and (b) the heterogeneous predominantly sublittoral community characterized by a lack of a complex of particular species. The local diversity of the heterotrophic flagellate community was low (on the average, 4.5 species per one sample 1 cm3 in volume). The overall distribution pattern of the flagellates was extremely heterogeneous. The large amount of species that were encountered only once causes a great variability in the species structure from one station to another. The total number of the species monotonously increased with the growth in the number of samples and no manifested saturation of the cumulative curve was reached. This indicates the potentially greater diversity of the heterotrophic flagellate species in the region studied.

  11. Grazing of heterotrophic flagellates on viruses is driven by feeding behaviour.

    PubMed

    Deng, Li; Krauss, Steffen; Feichtmayer, Judith; Hofmann, Roland; Arndt, Hartmut; Griebler, Christian

    2014-08-01

    The trophic interactions between viruses, bacteria and protists play a crucial role in structuring microbial communities and regulating nutrient and organic matter flux. Here, we show that the impact on viral density by heterotrophic flagellates is related to their feeding behaviour (feeding on sedimented particles - Thaumatomonas coloniensis, filter feeding of suspended particles - Salpingoeca sp., and actively searching raptorial feeding - Goniomonas truncata). Phage MS2 was co-incubated with flagellates and the natural bacterial and viral community originating from the same groundwater habitats where the flagellates were isolated. Three complementary assays, i.e. flow cytometry, qPCR and plaque assay, were used for enumeration of total viruses, total MS2 phages, and free and infectious MS2, respectively, to provide insights into the grazing mechanisms of the flagellates on viruses. Phage MS2 was actively removed by the suspension feeders T. coloniensis and Salpingoeca sp. in contrast with the actively raptoriale grazer G. truncata. The decline of viral titre was demonstrated to be caused by ingestion rather than random absorption by both qPCR and locating protein fluorescently labelled MS2 inside the flagellates. Further, we indicate that phages can be used as a minor carbon source for flagellates. Collectively, these data demonstrate that eliminating viruses can be an important function of protists in microbial food webs, carbon cycling and potentially water quality control.

  12. Magnetic separation of algae

    DOEpatents

    Nath, Pulak; Twary, Scott N.

    2016-04-26

    Described herein are methods and systems for harvesting, collecting, separating and/or dewatering algae using iron based salts combined with a magnetic field gradient to separate algae from an aqueous solution.

  13. Comparative toxicant sensitivity of sexual and asexual reproduction in the rotifer Brachionus calyciflorus

    SciTech Connect

    Snell, T.W.; Carmona, M.J.

    1995-03-01

    Cyclically parthenogenetic zooplankters like rotifers are important tools for assessing toxicity in aquatic environments. Sexual reproduction is an essential component of rotifer life cycles, but current toxicity tests utilize only asexual reproduction. The authors compared the effects of four toxicants on asexual and sexual reproduction of the rotifer Brachionus calyciflorus. Toxicants had a differential effect on sexual and asexual reproduction, with sexual reproduction consistently the most sensitive. Concentrations of 0.2 {mu}g/ml PCP (sodium pentachlorophenate) had no effect on the asexual reproductive rate, but significantly reduced sexual reproduction. Likewise, chlorpyrifos concentrations of 0.3 {mu}g/ml had no significant effect on asexual reproduction, but sexual reproduction was significantly reduced. There was no difference in NOECs, LOECs, and chronic values for asexual and sexual reproduction for cadmium and naphthol tests. However, comparison of toxicant effect levels revealed that sexual reproduction was more strongly reduced at each toxicant concentration. The four toxicants tested inhibited sexual reproduction 2 to 68 times more than asexual reproduction at the lowest observed effect concentrations. Toxicants inhibited sexual reproduction in its initial step: sexual female production. Because sexual reproduction is more sensitive, toxicity tests based exclusively on asexual reproduction may not be protective of rotifer life cycles.

  14. Ecological patterns of the rotifer communities in the Kaw River estuary (French Guiana)

    NASA Astrophysics Data System (ADS)

    Rougier, C.; Pourriot, R.; Lam-Hoai, T.; Guiral, D.

    2005-04-01

    A study of the rotifer fauna in the Kaw River estuary revealed significant quantitative and qualitative variations as a function of precipitation pattern and resulting hydrology and hydrochemistry. The rainy season (flood period) was characterized by the presence of about one hundred rotifer species of the periphytic continental type, each present at a very low average density (8 to 10 ind l -1). Rotifers generally constituted the majority of the zooplankton (above 70%). The dry season (low water period) was characterized by a small number (four) of species of the 'marine coastal' plankton type, showed the highest density peaks (>500 ind l -1). While the fluvial hydrodynamics during the rainy season contributed to a complete mixing of populations across the estuarine zone, the oceanic hydrodynamics during the dry season led to great population instability at the station level. At an annual scale, this estuarine zone is thus an essentially open environment that lacks a clearly-structured rotifer population, and which therefore most likely does not constitute a distinct, internally-functioning ecosystem.

  15. CONSUMPTIONS RATES OF SUMMER FLOUNDER LARVAE ON ROTIFER AND BRINE SHRIMP PREY DURING LARVAL REARING

    EPA Science Inventory

    Larval summer flounder Paralichthys dentatus were hatched and reared through metamorphosis in the laboratory. At several points in the rearing cycle, larvae were removed from their rearing chambers and placed in small bowls, where they were fed known quantities of the rotifer Bra...

  16. USING ROTIFER POPULATION DEMOGRAPHIC PARAMETERS TO ASSESS IMPACTS OF THE DEGRADATION PRODUCTS FROM TRINITROTOLUENE PHYTOREMEDIATION

    EPA Science Inventory

    The objective of this study was to evaluate the aquatic chronic lethal and sublethal toxicity effects from the phytoremediation of water contaminated with 2,4,6-trinitrotoluene (2,4,6-TNT) by the wetland plant species Myriophyllum aquaticum (parrot feather). Rotifers (Brachionus...

  17. Larval quality of aquacultured Florida pompano, Trachinotus carolinus L. fed rotifers enriched with selected commercial diets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Development of larviculture methods for marine finfish has been a major bottleneck to ensure a consistent and reliable source of seed stock. This study examined the effect of selected rotifer enrichment diets on growth, survival, and fatty acid content of larval Florida pompano, Trachinotus carolin...

  18. Larval performance of aquacultured Florida pompano, Trachinotus carolinus L. fed rotifers enriched with selected commercial diets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Development of larviculture methods for marine finfish has been a major bottleneck to ensure a consistent and reliable source of seed stock. This study examined the effect of selected rotifer enrichment diets on growth, survival, and fatty acid content of larval Florida pompano, Trachinotus carolin...

  19. Psammon rotifers in Central Vietnam, with the descriptions of three new species (Rotifera: Monogononta).

    PubMed

    Dang, Mau Trinh; Segers, Hendrik; Sanoamuang, La-Orsri

    2015-09-15

    In order to address the dearth of information on Rotifera in Vietnam, and especially on rotifers inhabiting freshwater psammon in Southeast Asia, we collected and examined twenty-five hygropsammon samples from Bau Thiem Lake, Thua Thien Hue Province, central Vietnam. A total of eighty-nine species-level rotifer taxa were identified, belonging to 21 genera and 13 families. Of these, 48 taxa (54%) are new to Vietnam, including three species, Lecane climacois Harring & Myers, 1926, Notommata cerberus (Gosse, 1886) and Trichocerca intermedia (Stenroos, 1898) that are new to the Oriental region, and three species, Lecane phapi n. sp., Lecane dorysimilis n. sp. and Trichocerca bauthiemensis n. sp. that are new to science. These, and some additional rare species are commented upon and illustrated. We estimated that the α-diversity of psammon rotifers in Bau Thiem Lake may be as high as 99 (SD=8.4; Chao2) or 115 (Jacknife2) taxa. These results indicate a high potential of rotifer diversity in the hygropsammon at Bau Thiem Lake, central Vietnam.

  20. Toxicity of various contaminants to two Ampeliscid amphipods and a rotifer

    SciTech Connect

    Dolah, R. Van; Maier, P.; Jones, J.; Fulton, M.; Scott, G.; Lewis, M.

    1995-12-31

    Comparative bioassays were completed on the amphipods Ampelisca abdita and A. verrilli, and the rotifer Branchionus plicatilis, to determine their relative sensitivity to cadmium and fluoranthene. All aqueous tests involved static exposures for 24 and 48 hrs in 30 pt seawater, except for the amphipod exposures in fluoranthene which involved a 96-hr exposure. The amphipod sediment assays involved 10-day static exposures to contaminant-spiked sediments. Rotifer tests involved 24 and 48 hr exposures to sediment porewater that was centrifuged from the spiked sediments. Results obtained from the aqueous bioassays indicated that both amphipod species were significantly more sensitive than the rotifer to all of the contaminants. Ampelisca abdita and A. verrilli were generally comparable in their sensitivity to cadmium and fluoranthene. Results obtained from the 10-day sediment bioassays on the amphipods indicated that A. verrilli was more sensitive than A. abdita to the cadmium exposures and both amphipod assays were much more sensitive than the rotifer assay. Only A. abdita showed significant mortality in the highest fluoranthene exposure of 50 mg/kg dry wt, 0.46% TOC.

  1. The complete mitochondrial genome of Pallisentis celatus (Acanthocephala) with phylogenetic analysis of acanthocephalans and rotifers.

    PubMed

    Pan, Ting Shuang; Nie, Pin

    2013-07-01

    Acanthocephalans are a small group of obligate endoparasites. They and rotifers are recently placed in a group called Syndermata. However, phylogenetic relationships within classes of acanthocephalans, and between them and rotifers, have not been well resolved, possibly due to the lack of molecular data suitable for such analysis. In this study, the mitochondrial (mt) genome was sequenced from Pallisentis celatus (Van Cleave, 1928), an acanthocephalan in the class Eoacanthocephala, an intestinal parasite of rice-field eel, Monopterus albus (Zuiew, 1793), in China. The complete mt genome sequence of P. celatus is 13 855 bp long, containing 36 genes including 12 protein-coding genes, 22 transfer RNAs (tRNAs) and 2 ribosomal RNAs (rRNAs) as reported for other acanthocephalan species. All genes are encoded on the same strand and in the same direction. Phylogenetic analysis indicated that acanthocephalans are closely related with a clade containing bdelloids, which then correlates with the clade containing monogononts. The class Eoacanthocephala, containing P. celatus and Paratenuisentis ambiguus (Van Cleave, 1921) was closely related to the Palaeacanthocephala. It is thus indicated that acanthocephalans may be just clustered among groups of rotifers. However, the resolving of phylogenetic relationship among all classes of acanthocephalans and between them and rotifers may require further sampling and more molecular data.

  2. Singly Flagellated Pseudomonas aeruginosa Chemotaxes Efficiently by Unbiased Motor Regulation

    PubMed Central

    Cai, Qiuxian; Li, Zhaojun; Ouyang, Qi

    2016-01-01

    ABSTRACT Pseudomonas aeruginosa is an opportunistic human pathogen that has long been known to chemotax. More recently, it has been established that chemotaxis is an important factor in the ability of P. aeruginosa to make biofilms. Genes that allow P. aeruginosa to chemotax are homologous with genes in the paradigmatic model organism for chemotaxis, Escherichia coli. However, P. aeruginosa is singly flagellated and E. coli has multiple flagella. Therefore, the regulation of counterclockwise/clockwise flagellar motor bias that allows E. coli to efficiently chemotax by runs and tumbles would lead to inefficient chemotaxis by P. aeruginosa, as half of a randomly oriented population would respond to a chemoattractant gradient in the wrong sense. How P. aeruginosa regulates flagellar rotation to achieve chemotaxis is not known. Here, we analyze the swimming trajectories of single cells in microfluidic channels and the rotations of cells tethered by their flagella to the surface of a variable-environment flow cell. We show that P. aeruginosa chemotaxes by symmetrically increasing the durations of both counterclockwise and clockwise flagellar rotations when swimming up the chemoattractant gradient and symmetrically decreasing rotation durations when swimming down the chemoattractant gradient. Unlike the case for E. coli, the counterclockwise/clockwise bias stays constant for P. aeruginosa. We describe P. aeruginosa’s chemotaxis using an analytical model for symmetric motor regulation. We use this model to do simulations that show that, given P. aeruginosa’s physiological constraints on motility, its distinct, symmetric regulation of motor switching optimizes chemotaxis. PMID:27048795

  3. Grazing rates and functional diversity of uncultured heterotrophic flagellates.

    PubMed

    Massana, Ramon; Unrein, Fernando; Rodríguez-Martínez, Raquel; Forn, Irene; Lefort, Thomas; Pinhassi, Jarone; Not, Fabrice

    2009-05-01

    Aquatic assemblages of heterotrophic protists are very diverse and formed primarily by organisms that remain uncultured. Thus, a critical issue is assigning a functional role to this unknown biota. Here we measured grazing rates of uncultured protists in natural assemblages (detected by fluorescent in situ hybridization (FISH)), and investigated their prey preference over several bacterial tracers in short-term ingestion experiments. These included fluorescently labeled bacteria (FLB) and two strains of the Roseobacter lineage and the family Flavobacteriaceae, of various cell sizes, which were offered alive and detected by catalyzed reporter deposition-FISH after the ingestion. We obtained grazing rates of the globally distributed and uncultured marine stramenopiles groups 4 and 1 (MAST-4 and MAST-1C) flagellates. Using FLB, the grazing rate of MAST-4 was somewhat lower than whole community rates, consistent with its small size. MAST-4 preferred live bacteria, and clearance rates with these tracers were up to 2 nl per predator per h. On the other hand, grazing rates of MAST-1C differed strongly depending on the tracer prey used, and these differences could not be explained by cell viability. Highest rates were obtained using FLB whereas the flavobacteria strain was hardly ingested. Possible explanations would be that the small flavobacteria cells were outside the effective size range of edible prey, or that MAST-1C selects against this particular strain. Our original dual FISH protocol applied to grazing experiments reveals important functional differences between distinct uncultured protists and offers the possibility to disentangle the complexity of microbial food webs.

  4. Diversity of cultured photosynthetic flagellates in the North East Pacific and Arctic Oceans in summer

    NASA Astrophysics Data System (ADS)

    Balzano, S.; Gourvil, P.; Siano, R.; Chanoine, M.; Marie, D.; Lessard, S.; Sarno, D.; Vaulot, D.

    2012-06-01

    During the MALINA cruise (summer 2009) an extensive effort was undertaken to isolate phytoplankton strains from the North East (NE) Pacific Ocean, the Bering Strait, and the Beaufort Sea. Strains were isolated by flow cytometry sorting (FCS) and pipetting before or after phytoplankton enrichment of seawater samples. Strains were isolated both onboard and back in the laboratory and cultured at 4 °C under light/dark conditions. Overall, we isolated and characterised by light microscopy and 18S rRNA gene sequencing 104 strains of photosynthetic flagellates which grouped into 21 genotypes (defined by 99.5% 18S rRNA gene sequence similarity) mainly affiliated to Chlorophyta and Heterokontophyta. The taxon most frequently isolated was an Arctic ecotype of the green algal genus Micromonas (Arctic Micromonas) which was almost the only phytoplankter recovered within picoplankton (≤ 2 μm) size range. Strains of Arctic Micromonas as well as three unidentified strains related to the same genus were identified in further details by sequencing the Internal Transcribed Spacer (ITS) region of the rRNA operon. The MALINA Micromonas strains share identical 18S rRNA and ITS sequences suggesting high genetic homogeneity within Arctic Micromonas. The unidentified strains form a genotype likely belonging to a new genus within the family Mamiellaceae to which Micromonas belongs. Other green algae genotypes from the genera Nephroselmis, Chlamydomonas, Pyramimonas were also isolated whereas Heterokontophyta included Pelagophyceae, Dictyochophyceae and Chrysophyceae. Dictyochophyceae included Pedinellales which could not be identified to the genus level whereas Chrysophyceae comprised Dinobryon faculiferum. Moreover, we isolated Rhodomonas sp. as well as a few Haptophyta and dinoflagellates. We identified the dinoflagellate Woloszynskia cincta by Scanning Electron Microscopy (SEM) and 28S rRNA gene sequencing. Our morphological analyses show that this species possess the diagnostic

  5. Diversity of cultured photosynthetic flagellates in the northeast Pacific and Arctic Oceans in summer

    NASA Astrophysics Data System (ADS)

    Balzano, S.; Gourvil, P.; Siano, R.; Chanoine, M.; Marie, D.; Lessard, S.; Sarno, D.; Vaulot, D.

    2012-11-01

    During the MALINA cruise (summer 2009), an extensive effort was undertaken to isolate phytoplankton strains from the northeast (NE) Pacific Ocean, the Bering Strait, the Chukchi Sea, and the Beaufort Sea. In order to characterise the main photosynthetic microorganisms occurring in the Arctic during the summer season, strains were isolated by flow cytometry sorting (FCS) and single cell pipetting before or after phytoplankton enrichment of seawater samples. Strains were isolated both onboard and back in the laboratory and cultured at 4 °C under light/dark conditions. Overall, we isolated and characterised by light microscopy and 18 S rRNA gene sequencing 104 strains of photosynthetic flagellates which grouped into 21 genotypes (defined by 99.5% 18 S rRNA gene sequence similarity), mainly affiliated to Chlorophyta and Heterokontophyta. The taxon most frequently isolated was an Arctic ecotype of the green algal genus Micromonas (Arctic Micromonas), which was nearly the only phytoplankter recovered within the picoplankton (< 2 μm) size range. Strains of Arctic Micromonas as well as other strains from the same class (Mamiellophyceae) were identified in further detail by sequencing the internal transcribed spacer (ITS) region of the rRNA operon. The MALINA Micromonas strains share identical 18 S rRNA and ITS sequences suggesting high genetic homogeneity within Arctic Micromonas. Three other Mamiellophyceae strains likely belong to a new genus. Other green algae from the genera Nephroselmis, Chlamydomonas, and Pyramimonas were also isolated, whereas Heterokontophyta included some unidentified Pelagophyceae, Dictyochophyceae (Pedinellales), and Chrysophyceae (Dinobryon faculiferum). Moreover, we isolated some Cryptophyceae (Rhodomonas sp.) as well as a few Prymnesiophyceae and dinoflagellates. We identified the dinoflagellate Woloszynskia cincta by scanning electron microscopy (SEM) and 28 S rRNA gene sequencing. Our morphological analyses show that this species possess

  6. Are algae relevant to the detritus-based food web in tank-bromeliads?

    PubMed

    Brouard, Olivier; Le Jeune, Anne-Hélène; Leroy, Céline; Cereghino, Régis; Roux, Olivier; Pelozuelo, Laurent; Dejean, Alain; Corbara, Bruno; Carrias, Jean-François

    2011-01-01

    We assessed the occurrence of algae in five species of tank-bromeliads found in contrasting environmental sites in a Neotropical, primary rainforest around the Nouragues Research Station, French Guiana. The distributions of both algal abundance and biomass were examined based on physical parameters, the morphological characteristics of bromeliad species and with regard to the structure of other aquatic microbial communities held in the tanks. Algae were retrieved in all of the bromeliad species with mean densities ranging from ∼10(2) to 10(4) cells/mL. Their biomass was positively correlated to light exposure and bacterial biomass. Algae represented a tiny component of the detrital food web in shaded bromeliads but accounted for up to 30 percent of the living microbial carbon in the tanks of Catopsis berteroniana, located in a highly exposed area. Thus, while nutrient supplies are believed to originate from wind-borne particles and trapped insects (i.e., allochtonous organic matter), our results indicate that primary producers (i.e., autochtonous organic matter) are present in this insectivorous bromeliad. Using a 24-h incubation of size-fractionated and manipulated samples from this plant, we evaluated the impact of mosquito foraging on algae, other microorganisms and rotifers. The prey assemblages were greatly altered by the predation of mosquito larvae. Grazing losses indicated that the dominant algal taxon, Bumilleriopsis sp., like protozoa and rotifers, is a significant part of the diet of mosquito larvae. We conclude that algae are a relevant functional community of the aquatic food web in C. berteroniana and might form the basis of a complementary non-detrital food web.

  7. Are Algae Relevant to the Detritus-Based Food Web in Tank-Bromeliads?

    PubMed Central

    Brouard, Olivier; Le Jeune, Anne-Hélène; Leroy, Céline; Cereghino, Régis; Roux, Olivier; Pelozuelo, Laurent; Dejean, Alain; Corbara, Bruno; Carrias, Jean-François

    2011-01-01

    We assessed the occurrence of algae in five species of tank-bromeliads found in contrasting environmental sites in a Neotropical, primary rainforest around the Nouragues Research Station, French Guiana. The distributions of both algal abundance and biomass were examined based on physical parameters, the morphological characteristics of bromeliad species and with regard to the structure of other aquatic microbial communities held in the tanks. Algae were retrieved in all of the bromeliad species with mean densities ranging from ∼102 to 104 cells/mL. Their biomass was positively correlated to light exposure and bacterial biomass. Algae represented a tiny component of the detrital food web in shaded bromeliads but accounted for up to 30 percent of the living microbial carbon in the tanks of Catopsis berteroniana, located in a highly exposed area. Thus, while nutrient supplies are believed to originate from wind-borne particles and trapped insects (i.e., allochtonous organic matter), our results indicate that primary producers (i.e., autochtonous organic matter) are present in this insectivorous bromeliad. Using a 24-h incubation of size-fractionated and manipulated samples from this plant, we evaluated the impact of mosquito foraging on algae, other microorganisms and rotifers. The prey assemblages were greatly altered by the predation of mosquito larvae. Grazing losses indicated that the dominant algal taxon, Bumilleriopsis sp., like protozoa and rotifers, is a significant part of the diet of mosquito larvae. We conclude that algae are a relevant functional community of the aquatic food web in C. berteroniana and might form the basis of a complementary non-detrital food web. PMID:21625603

  8. Species-specific separation of lake plankton reveals divergent food assimilation patterns in rotifers

    PubMed Central

    Burian, Alfred; Kainz, Martin J; Schagerl, Michael; Yasindi, Andrew

    2014-01-01

    1. The analysis of functional groups with a resolution to the individual species level is a basic requirement to better understand complex interactions in aquatic food webs. Species-specific stable isotope analyses are currently applied to analyse the trophic role of large zooplankton or fish species, but technical constraints complicate their application to smaller-sized plankton. 2. We investigated rotifer food assimilation during a short-term microzooplankton bloom in the East African soda lake Nakuru by developing a method for species-specific sampling of rotifers. 3. The two dominant rotifers, Brachionus plicatilis and Brachionus dimidiatus, were separated to single-species samples (purity >95%) and significantly differed in their isotopic values (4.1‰ in δ13C and 1.5‰ in δ15N). Bayesian mixing models indicated that isotopic differences were caused by different assimilation of filamentous cyanobacteria and particles <2 μm and underlined the importance of species-specific sampling of smaller plankton compartments. 4. A main difference was that the filamentous cyanobacterium Arthrospira fusiformis, which frequently forms blooms in African soda lakes, was an important food source for the larger-sized B. plicatilis (48%), whereas it was hardly ingested by B. dimidiatus. Overall, A. fusiformis was, relative to its biomass, assimilated to small extents, demonstrating a high grazing resistance of this species. 5. In combination with high population densities, these results demonstrate a strong potential of rotifer blooms to shape phytoplankton communities and are the first in situ demonstration of a quantitatively important direct trophic link between rotifers and filamentous cyanobacteria. PMID:25866422

  9. Settlement of marine periphytic algae in a tropical estuary

    NASA Astrophysics Data System (ADS)

    Nayar, S.; Goh, B. P. L.; Chou, L. M.

    2005-08-01

    This note describes settlement studies of marine periphytic algae on glass substrata in a tropical estuary in Singapore. The rates of production in terms of 14C radiotracer uptake, biomass in terms of chlorophyll a, community structure and cell abundance were measured from the settled periphytic algae at various depths in the water column and compared with the prevailing hydrographical conditions. Relatively higher periphytic algal settlement was observed at 1 m depth, even though it was not statistically different from other depths. Diatoms such as Skeletonema costatum and Thalassiosira rotula dominated the assemblage, together with the marine cyanobacteria Synechococcus sp. The three settlement parameters viz., periphytic algal production, chlorophyll a and cell counts showed significant differences between the days of settlement, with no significant differences observed for different depths. The periphytic algal community in this study comprised 30 microalgal species, dominated by diatoms (78%), followed by cyanobacteria (19% - primarily Synechococcus sp.), green flagellates (1%), dinoflagellates (1%) and other forms accounting for the remaining 1% of the total cell counts. Correlation studies and principal component analysis (PCA) revealed significant influence of silicate concentrations in the water column with the settlement of periphytic algae in this estuary. Though photoinhibited at the surface, photosynthetically available radiation did not seem to influence the overall settlement of periphytic algae. Diatoms and Synechococcus in the periphytic algal community were influenced by water temperature, PAR, pH and dissolved oxygen as seen in the PCA plots.

  10. Lypd8 promotes the segregation of flagellated microbiota and colonic epithelia.

    PubMed

    Okumura, Ryu; Kurakawa, Takashi; Nakano, Takashi; Kayama, Hisako; Kinoshita, Makoto; Motooka, Daisuke; Gotoh, Kazuyoshi; Kimura, Taishi; Kamiyama, Naganori; Kusu, Takashi; Ueda, Yoshiyasu; Wu, Hong; Iijima, Hideki; Barman, Soumik; Osawa, Hideki; Matsuno, Hiroshi; Nishimura, Junichi; Ohba, Yusuke; Nakamura, Shota; Iida, Tetsuya; Yamamoto, Masahiro; Umemoto, Eiji; Sano, Koichi; Takeda, Kiyoshi

    2016-04-01

    Colonic epithelial cells are covered by thick inner and outer mucus layers. The inner mucus layer is free of commensal microbiota, which contributes to the maintenance of gut homeostasis. In the small intestine, molecules critical for prevention of bacterial invasion into epithelia such as Paneth-cell-derived anti-microbial peptides and regenerating islet-derived 3 (RegIII) family proteins have been identified. Although there are mucus layers providing physical barriers against the large number of microbiota present in the large intestine, the mechanisms that separate bacteria and colonic epithelia are not fully elucidated. Here we show that Ly6/PLAUR domain containing 8 (Lypd8) protein prevents flagellated microbiota invading the colonic epithelia in mice. Lypd8, selectively expressed in epithelial cells at the uppermost layer of the large intestinal gland, was secreted into the lumen and bound flagellated bacteria including Proteus mirabilis. In the absence of Lypd8, bacteria were present in the inner mucus layer and many flagellated bacteria invaded epithelia. Lypd8(-/-) mice were highly sensitive to intestinal inflammation induced by dextran sulfate sodium (DSS). Antibiotic elimination of Gram-negative flagellated bacteria restored the bacterial-free state of the inner mucus layer and ameliorated DSS-induced intestinal inflammation in Lypd8(-/-) mice. Lypd8 bound to flagella and suppressed motility of flagellated bacteria. Thus, Lypd8 mediates segregation of intestinal bacteria and epithelial cells in the colon to preserve intestinal homeostasis. PMID:27027293

  11. Effects of Multi-metal (Cu, Zn, Cd, Cr, and Mn) Mixtures on the Reproduction of Freshwater Rotifer Brachionus calyciflorus.

    PubMed

    Xu, Xiao-Ping; Xi, Yi-Long; Huang, Lin; Xiang, Xian-Ling

    2015-12-01

    In the field, organisms are usually exposed to mixtures of various metals. However, the effects of multi-metal mixtures on growth and reproduction of rotifers remain unknown. In the present study, effects of multi-metal mixtures (Cu, Zn, Cd, Cr, and Mn) on reproduction of the freshwater rotifer Brachionus calyciflorus were assessed by determining various endpoints, including the ratio of ovigerous females to nonovigerous females, the ratio of mictic to amictic females, the mictic rate, the fertilization rate, the population growth rate, and the resting eggs production. The results demonstrated that reproduction of rotifers was significantly affected by all multi-metal mixtures assessed. Moreover, the ratio of mictic to amictic females was the most sensitive endpoint and might be suitable to evaluate effects of multi-metal mixtures to rotifers. PMID:26464391

  12. Effects of Multi-metal (Cu, Zn, Cd, Cr, and Mn) Mixtures on the Reproduction of Freshwater Rotifer Brachionus calyciflorus.

    PubMed

    Xu, Xiao-Ping; Xi, Yi-Long; Huang, Lin; Xiang, Xian-Ling

    2015-12-01

    In the field, organisms are usually exposed to mixtures of various metals. However, the effects of multi-metal mixtures on growth and reproduction of rotifers remain unknown. In the present study, effects of multi-metal mixtures (Cu, Zn, Cd, Cr, and Mn) on reproduction of the freshwater rotifer Brachionus calyciflorus were assessed by determining various endpoints, including the ratio of ovigerous females to nonovigerous females, the ratio of mictic to amictic females, the mictic rate, the fertilization rate, the population growth rate, and the resting eggs production. The results demonstrated that reproduction of rotifers was significantly affected by all multi-metal mixtures assessed. Moreover, the ratio of mictic to amictic females was the most sensitive endpoint and might be suitable to evaluate effects of multi-metal mixtures to rotifers.

  13. Negative consequences of glacial turbidity for the survival of freshwater planktonic heterotrophic flagellates.

    PubMed

    Sommaruga, Ruben; Kandolf, Georg

    2014-02-17

    Heterotrophic (phagotrophic) flagellates are key components of planktonic food webs in freshwater and marine ecosystems because they are the main consumers of bacteria. Although they are ubiquitous in aquatic ecosystems, they were numerically undetectable in turbid glacier-fed lakes. Here we show that glacial particles had negative effects on the survival and growth of heterotrophic flagellates. The effect of glacial particles was concentration-dependent and was caused by their interference with bacterial uptake rather than by physical damage. These results are the first to reveal why establishment of heterotrophic flagellates populations is hindered in very turbid glacial lakes. Because glaciers are vanishing around the world, recently formed turbid meltwater lakes represent an excellent opportunity to understand the environmental conditions that probably shaped the establishment of lake communities at the end of the last glaciation.

  14. Molecular Comparisons of Freshwater and Marine Isolates of the Same Morphospecies of Heterotrophic Flagellates

    PubMed Central

    Scheckenbach, Frank; Wylezich, Claudia; Mylnikov, Alexander P.; Weitere, Markus; Arndt, Hartmut

    2006-01-01

    Heterotrophic flagellates are key components of all ecosystems. Understanding the patterns of biodiversity of these organisms is thus particularly important. Here we analyzed the intraspecific diversity of 10 morphospecies of heterotrophic flagellates comprising representatives of the Apusozoa (2 morphospecies) and Kinetoplastea (8 morphospecies), all belonging to the most common flagellates with worldwide distribution. Most morphospecies showed a mixing of lineages isolated from diverse habitats, indicating that some lineages of these morphospecies had been able to colonize different habitats several times. Furthermore, our results revealed remarkable levels of genetic divergence within most of the morphospecies studied, underlining the difficulty of correctly determining species by means of morphology alone. Many cryptic or pseudocryptic species seem to occur. Our results revealed clear divergence between marine and freshwater lineages of the morphospecies Ancyromonas sigmoides, showing that freshwater lineages have not been able to colonize marine environments and marine lineages have not been able to colonize freshwater environments for a long time. PMID:17021215

  15. Channeling of bacterioplanktonic production toward phagotrophic flagellates and ciliates under different seasonal conditions in a river.

    PubMed

    Iriberri, J; Ayo, B; Unanue, M; Barcina, I; Egea, L

    1993-09-01

    The objective of this study was to analyze the flux of biomass through the communities of bacteria and phagotrophic protists in the cold and warm conditions occurring seasonally in Butrón River. Bacterial and heterotrophic protistan (flagellate and ciliate) abundance was determined by epifluorescence direct counts; protistan grazing on planktonic bacteria was measured from fluorescently labeled bacteria uptake rates; and the estimate of bacterial secondary production was obtained from [(3)H]thymidine incorporation rates. The abundance of bacterial, flagellate, and ciliate communities was similar during cold and warm situations. However, we observed that estimates of dynamic parameters, i.e., secondary bacterial production and protistan grazing, in both situations were noticeably different. In the warm situation, grazing rates of flagellates and ciliates (bacteria per protist per hour) were, respectively, 7 times and 18 times higher than those determined in the cold situation, and the grazing rates of the protistan communities (bacteria per protists present in 1 ml of water per hour) increased up to 5 times in the case of flagellates and 42 times in the case of ciliates. Estimates of bacterial secondary production were also higher during the warm situation, showing a ninefold increase. The percentage of bacterial production preyed upon by flagellates or ciliates was not significantly different between the two conditions. These results showed that in the different conditions of a system, the flux of biomass between the trophic levels may be quite different although this process may not be reflected in the abundance of each community of bacteria, flagellates, and ciliates.

  16. The position of flagellated protists in the system of lower eukaryotes.

    PubMed

    Starobogatov, Y I

    1995-01-01

    The division of Eukaryota into 8 kingdoms united into 3 superkingdoms is briefly discussed with the rejection of the hypothesis of symbiogenesis and of primary nature of the dinokaryon. It is asserted that Pascher's main hypothesis remains valid. The heterotrophic flagellated and amoeboid forms must be included into different groups of flagellated beings. Some of them: Saprolegniomycetes, Hyphochytridiomycetes, Slopalinata, Cryptaxohelid Heliozoa have been already put into chromophytan branch. Others differ from autotrophic groups more sharply and their taxonomic position may be stated now only tentatively and will be specified as a result of future studies.

  17. Allele Sharing and Evidence for Sexuality in a Mitochondrial Clade of Bdelloid Rotifers

    PubMed Central

    Signorovitch, Ana; Hur, Jae; Gladyshev, Eugene; Meselson, Matthew

    2015-01-01

    Rotifers of Class Bdelloidea are common freshwater invertebrates of ancient origin whose apparent asexuality has posed a challenge to the view that sexual reproduction is essential for long-term evolutionary success in eukaryotes and to hypotheses for the advantage of sex. The possibility nevertheless exists that bdelloids reproduce sexually under unknown or inadequately investigated conditions. Although certain methods of population genetics offer definitive means for detecting infrequent or atypical sex, they have not previously been applied to bdelloid rotifers. We conducted such a test with bdelloids belonging to a mitochondrial clade of Macrotrachela quadricornifera. This revealed a striking pattern of allele sharing consistent with sexual reproduction and with meiosis of an atypical sort, in which segregation occurs without requiring homologous chromosome pairs. PMID:25977472

  18. Allele Sharing and Evidence for Sexuality in a Mitochondrial Clade of Bdelloid Rotifers.

    PubMed

    Signorovitch, Ana; Hur, Jae; Gladyshev, Eugene; Meselson, Matthew

    2015-06-01

    Rotifers of Class Bdelloidea are common freshwater invertebrates of ancient origin whose apparent asexuality has posed a challenge to the view that sexual reproduction is essential for long-term evolutionary success in eukaryotes and to hypotheses for the advantage of sex. The possibility nevertheless exists that bdelloids reproduce sexually under unknown or inadequately investigated conditions. Although certain methods of population genetics offer definitive means for detecting infrequent or atypical sex, they have not previously been applied to bdelloid rotifers. We conducted such a test with bdelloids belonging to a mitochondrial clade of Macrotrachela quadricornifera. This revealed a striking pattern of allele sharing consistent with sexual reproduction and with meiosis of an atypical sort, in which segregation occurs without requiring homologous chromosome pairs.

  19. Resurrecting Van Leeuwenhoek's rotifers: a reappraisal of the role of disaccharides in anhydrobiosis.

    PubMed Central

    Tunnacliffe, A; Lapinski, J

    2003-01-01

    In 1702, Van Leeuwenhoek was the first to describe the phenomenon of anhydrobiosis in a species of bdelloid rotifer, Philodina roseola. It is the purpose of this review to examine what has been learned since then about the extreme desiccation tolerance in rotifers and how this compares with our understanding of anhydrobiosis in other organisms. Remarkably, much of what is known today about the requirements for successful anhydrobiosis, and the degree of biostability conferred by the dry state, was already determined in principle by the time of Spallanzani in the late 18th century. Most modern research on anhydrobiosis has emphasized the importance of the non-reducing disaccharides trehalose and sucrose, one or other sugar being present at high concentrations during desiccation of anhydrobiotic nematodes, brine shrimp cysts, bakers' yeast, resurrection plants and plant seeds. These sugars are proposed to act as water replacement molecules, and as thermodynamic and kinetic stabilizers of biomolecules and membranes. In apparent contradiction of the prevailing models, recent experiments from our laboratory show that bdelloid rotifers undergo anhydrobiosis without producing trehalose or any analogous molecule. This has prompted us to critically re-examine the association of disaccharides with anhydrobiosis in the literature. Surprisingly, current hypotheses are based almost entirely on in vitro data: there is very limited information which is more than simply correlative in the literature on living systems. In many species, disaccharide accumulation occurs at approximately the same time as desiccation tolerance is acquired. However, several studies indicate that these sugars are not sufficient for anhydrobiosis; furthermore, there is no conclusive evidence, through mutagenesis or functional knockout experiments, for example, that sugars are necessary for anhydrobiosis. Indeed, some plant seeds and micro-organisms, like the rotifer, exhibit excellent desiccation

  20. Acute toxicity of toluene, hexane, xylene, and benzene to the rotifers Brachionus calyciflorus and Brachionus plicatilis

    SciTech Connect

    Ferrando, M.D.; Andreu-Moliner, E. )

    1992-08-01

    A large number of studies on the biological effects of oil pollution in the aquatic environment deal with the effects of whole crude or refined oils or their water-soluble fractions. However, low boiling, aromatic hydrocarbons, which are probably the most toxic constituents of oil, have until now not been examined in sufficient detail. Toluene, benzene and xylene, constitute a major component of various oils. They may be readily lost by weathering but are toxic in waters that are relatively stagnant and are chronically polluted. Korn et al. have stated that toluene is more toxic than many other hydrocarbons such as benzene, though the latter are more water-soluble. Report of the effects of exposure to organic solvents like hexane or toluene are still limited although organic solvents are a well-known group of neurointoxicants. Various benzene derivates continue to be used as chemical intermediates, solvents, pesticides, so on, in spite of incomplete knowledge of their chronic toxicity. The majority of toxicity studies about the effects of pollution on aquatic organisms under controlled conditions have used either fish or the cladoceran Daphnia magna and there are few studies reported using rotifers. The effects of herbicides on population variables of laboratory rotifer cultures have been investigated. Rotifers are one of the main sources of zooplankton production and they have an important ecological significance in the aquatic environment. The present work was designed to investigate the effect of short-term exposure to some petroleum derivates which might be expected to occur immediately under an oil-slick, on freshwater and brackish environment rotifers. 18 refs., 1 tab.

  1. Chronic effects of PFOA and PFOS on sexual reproduction of freshwater rotifer Brachionus calyciflorus.

    PubMed

    Zhang, Lilan; Niu, Junfeng; Wang, Yujuan; Shi, Jianghong; Huang, Qingguo

    2014-11-01

    Rotifers play an important role in the dynamics of freshwater and coastal marine ecosystems, and are also important tools for assessing toxicity in aquatic environments. In this study, the effects of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) on the population growth rate and resting egg production of rotifer Brachionus calyciflorus were investigated. Reproductive bioassays indicated that PFOS increased the rotifer population growth rate at the concentration ⩽2.0 mg L(-1), and inhibited it at higher concentrations. For PFOA, the inhibition of population growth rate was observed when the concentration was greater than 4.0 mg L(-1). Exposure to PFOS (0.25 mg L(-1)) or PFOA (2.0 mg L(-1)) increased the mictic ratios of unexposed rotifer offspring. Population variation and increased mictic ratios were likely the two major factors leading to decline of resting egg production. The resting eggs formed under exposure to PFOA/PFOS in the range of 0.125-2.0 mg L(-1) showed higher hatching percentages in the control medium than that without PFOA/PFOS exposure. When the resting eggs were formed in the control medium and incubated in media with different levels of PFOA/PFOS, higher hatching percentages were induced by PFOS but lower hatching percentages induced by PFOA. The effects on the hatching rate of resting eggs with PFOA/PFOS exposure during the hatching period were greater than those with exposure during resting egg formation period, and the effect of PFOS was greater than that of PFOA. Both PFOA and PFOS exhibited slight effect on the hatching pattern.

  2. Measurement of Survival Time in Brachionus Rotifers: Synchronization of Maternal Conditions.

    PubMed

    Kaneko, Gen; Yoshinaga, Tatsuki; Gribble, Kristin E; Welch, David M; Ushio, Hideki

    2016-01-01

    Rotifers are microscopic cosmopolitan zooplankton used as models in ecotoxicological and aging studies due to their several advantages such as short lifespan, ease of culture, and parthenogenesis that enables clonal culture. However, caution is required when measuring their survival time as it is affected by maternal age and maternal feeding conditions. Here we provide a protocol for powerful and reproducible measurement of the survival time in Brachionus rotifers following a careful synchronization of culture conditions over several generations. Empirically, poor synchronization results in early mortality and a gradual decrease in survival rate, thus resulting in weak statistical power. Indeed, under such conditions, calorie restriction (CR) failed to significantly extend the lifespan of B. plicatilis although CR-induced longevity has been demonstrated with well-synchronized rotifer samples in past and present studies. This protocol is probably useful for other invertebrate models, including the fruitfly Drosophila melanogaster and the nematode Caenorhabditis elegans, because maternal age effects have also been reported in these species. PMID:27500471

  3. DNA barcoding of freshwater rotifera in Mexico: evidence of cryptic speciation in common rotifers.

    PubMed

    García-Morales, A E; Elías-Gutiérrez, M

    2013-11-01

    DNA barcodes are useful tools to identify and discover new species in a wide range of taxa. Here, we report the first barcode study of monogonont rotifers from fresh and brackish waters in Mexico, and discuss the taxonomic implications of this work. We used DNA barcodes based on the sequence of cytochrome oxidase I to examine patterns of divergence among 417 specimens that represented 63 morphological taxa of rotifers. The mean sequence divergence among conspecific rotifer individuals was 0.75%, whereas the mean sequence divergence among congeneric taxa was 20.8%. The barcodes could discriminate between all the morphospecies identified. Moreover, the barcoding data revealed the presence of possible cryptic species in Ascomorpha ovalis, Lecane bulla, L. cornuta, L. curvicornis, L. crepida, L. lunaris, L. hastata, Platyias quadricornis, Keratella cochlearis, Brachionus calyciflorus and Testudinella patina, as well as in some forms and varieties such as B. quadridentatus f. brevispinus, B. quadridentatus f. cluniorbicularis and Mytilina ventralis var. macracantha. Barcode analysis also enabled some forms and varieties of common species to be identified as separate species. The results obtained support recent taxonomic revisions, such as the recognition of the genus Plationus, and the presence of cryptic speciation in L. bulla. This work shows that DNA barcoding identifies species effectively, can aid taxonomists by identifying cryptic species, and is an important tool for resolving taxonomic controversies.

  4. Bleomycin-Induced Flagellate Erythema in a Patient Diagnosed with Ovarian Yolk Sac Tumor

    PubMed Central

    Boussios, Stergios; Moschetta, Michele; McLachlan, Jennifer; Banerjee, Susana

    2015-01-01

    Flagellate linear hyperpigmentation can rarely be caused by the chemotherapy agent, bleomycin. Herein, we describe the case of a 20-year-old woman treated with bleomycin for an ovarian yolk sac tumor and review the prominent features of this form of dermatitis. PMID:26798532

  5. Algae Derived Biofuel

    SciTech Connect

    Jahan, Kauser

    2015-03-31

    One of the most promising fuel alternatives is algae biodiesel. Algae reproduce quickly, produce oils more efficiently than crop plants, and require relatively few nutrients for growth. These nutrients can potentially be derived from inexpensive waste sources such as flue gas and wastewater, providing a mutual benefit of helping to mitigate carbon dioxide waste. Algae can also be grown on land unsuitable for agricultural purposes, eliminating competition with food sources. This project focused on cultivating select algae species under various environmental conditions to optimize oil yield. Membrane studies were also conducted to transfer carbon di-oxide more efficiently. An LCA study was also conducted to investigate the energy intensive steps in algae cultivation.

  6. Contrasting bacterial strategies to coexist with a flagellate predator in an experimental microbial assemblage.

    PubMed

    Pernthaler, J; Posch, T; Simek, K; Vrba, J; Amann, R; Psenner, R

    1997-02-01

    We studied predator-induced changes within a slowly growing mixed microbial assemblage that was sustained by algal exudates in a continuous cultivation system. In situ hybridization with fluorescent monolabeled oligonucleotide probes was used for a tentative community analysis. This method also allowed us to quantify the proportions of predators with ingested bacteria of different taxonomic groups. In addition, we determined grazing rates on bacteria with fluorescently labelled prey. Bacteria belonging to the alpha and beta subdivisions of the phylum Proteobacteria ((alpha)- and (beta)-Proteobacteria, respectively) showed very different responses to the addition of a bacterivorous flagellate, Bodo saltans. Within one day, filamentous protist-inedible bacteria developed; these belonged to the (beta)-Proteobacteria and constituted between 8.7 and 34% of bacteria from this subgroup. Total abundance of (beta)-Proteobacteria decreased from 3.05 x 10(sup6) to 0.23 x 10(sup6) cells ml(sup-1), and estimated cell division rates were low. Other morphologically inconspicuous protist-edible bacteria belonging to the (alpha)-Proteobacteria were found to respond to predation by an increase in growth rate. Although these bacteria were heavily grazed upon, as on average >85% of flagellate cells had ingested (alpha)-Proteobacteria, they numerically dominated after the addition of B. saltans (mean, 1.35 x 10(sup6) cells ml(sup-1)). It was thus mainly those fast-dividing strains of (alpha)-Proteobacteria that supported the growth of the flagellate population. We conclude that bacteria in mixed assemblages can adopt at least two distinct strategies as a reaction to intense flagellate predation: to outgrow predation pressure or to develop inedible, inactive filaments. Since these strategies occurred within 24 h after the addition of the flagellate, we hypothesize that chemical stimuli released by the predator may have triggered bacterial responses. PMID:16535516

  7. Contrasting Bacterial Strategies To Coexist with a Flagellate Predator in an Experimental Microbial Assemblage

    PubMed Central

    Pernthaler, J.; Posch, T.; Simek, K.; Vrba, J.; Amann, R.; Psenner, R.

    1997-01-01

    We studied predator-induced changes within a slowly growing mixed microbial assemblage that was sustained by algal exudates in a continuous cultivation system. In situ hybridization with fluorescent monolabeled oligonucleotide probes was used for a tentative community analysis. This method also allowed us to quantify the proportions of predators with ingested bacteria of different taxonomic groups. In addition, we determined grazing rates on bacteria with fluorescently labelled prey. Bacteria belonging to the alpha and beta subdivisions of the phylum Proteobacteria ((alpha)- and (beta)-Proteobacteria, respectively) showed very different responses to the addition of a bacterivorous flagellate, Bodo saltans. Within one day, filamentous protist-inedible bacteria developed; these belonged to the (beta)-Proteobacteria and constituted between 8.7 and 34% of bacteria from this subgroup. Total abundance of (beta)-Proteobacteria decreased from 3.05 x 10(sup6) to 0.23 x 10(sup6) cells ml(sup-1), and estimated cell division rates were low. Other morphologically inconspicuous protist-edible bacteria belonging to the (alpha)-Proteobacteria were found to respond to predation by an increase in growth rate. Although these bacteria were heavily grazed upon, as on average >85% of flagellate cells had ingested (alpha)-Proteobacteria, they numerically dominated after the addition of B. saltans (mean, 1.35 x 10(sup6) cells ml(sup-1)). It was thus mainly those fast-dividing strains of (alpha)-Proteobacteria that supported the growth of the flagellate population. We conclude that bacteria in mixed assemblages can adopt at least two distinct strategies as a reaction to intense flagellate predation: to outgrow predation pressure or to develop inedible, inactive filaments. Since these strategies occurred within 24 h after the addition of the flagellate, we hypothesize that chemical stimuli released by the predator may have triggered bacterial responses. PMID:16535516

  8. Contrasting bacterial strategies to coexist with a flagellate predator in an experimental microbial assemblage.

    PubMed

    Pernthaler, J; Posch, T; Simek, K; Vrba, J; Amann, R; Psenner, R

    1997-02-01

    We studied predator-induced changes within a slowly growing mixed microbial assemblage that was sustained by algal exudates in a continuous cultivation system. In situ hybridization with fluorescent monolabeled oligonucleotide probes was used for a tentative community analysis. This method also allowed us to quantify the proportions of predators with ingested bacteria of different taxonomic groups. In addition, we determined grazing rates on bacteria with fluorescently labelled prey. Bacteria belonging to the alpha and beta subdivisions of the phylum Proteobacteria ((alpha)- and (beta)-Proteobacteria, respectively) showed very different responses to the addition of a bacterivorous flagellate, Bodo saltans. Within one day, filamentous protist-inedible bacteria developed; these belonged to the (beta)-Proteobacteria and constituted between 8.7 and 34% of bacteria from this subgroup. Total abundance of (beta)-Proteobacteria decreased from 3.05 x 10(sup6) to 0.23 x 10(sup6) cells ml(sup-1), and estimated cell division rates were low. Other morphologically inconspicuous protist-edible bacteria belonging to the (alpha)-Proteobacteria were found to respond to predation by an increase in growth rate. Although these bacteria were heavily grazed upon, as on average >85% of flagellate cells had ingested (alpha)-Proteobacteria, they numerically dominated after the addition of B. saltans (mean, 1.35 x 10(sup6) cells ml(sup-1)). It was thus mainly those fast-dividing strains of (alpha)-Proteobacteria that supported the growth of the flagellate population. We conclude that bacteria in mixed assemblages can adopt at least two distinct strategies as a reaction to intense flagellate predation: to outgrow predation pressure or to develop inedible, inactive filaments. Since these strategies occurred within 24 h after the addition of the flagellate, we hypothesize that chemical stimuli released by the predator may have triggered bacterial responses.

  9. Regulation of Rotifer Community by Predation of Cyclops vicinus (Copepoda) in the ímov Reservoir in Spring

    NASA Astrophysics Data System (ADS)

    Devetter, Miloslav; Sea, Jaromír

    2006-02-01

    The structuring role and predation impact of Cyclops vicinus on the rotifer community was studied using in situ enclosure experiments in ímov Reservoir during the spring of 2000. Seasonal changes in abundance and birth rates of the rotifer species Synchaeta lakowitziana , Polyarthra spp., Keratella cochlearis and Kellicottia longispina were related to predation pressure, i.e. selectivity and cropping rates of C. vicinus . All four rotifer species were found to be consumed by C. vicinus whose predation rates showed a marked succession through the spring period and corresponded to changes in the relative abundance of the pelagic species. The highest predation rates exhibited by C. vicinus were on Synchaeta lakowitziana and Polyarthra spp., being 11.3 and 6.4 ind Cyclops -1 day-1 respectively. The activity of the predator switched among three types of preferred food during the spring period. The most preferred, Synchaeta, was replaced by Polyarthra after Synchaeta became extinct and these species were replaced by Keratella when both soft-bodied forms were not available in sufficient quantities. Loricated species (K. cochlearis and K. longispina) were consumed at a slower rate. We calculated the proportion of rotifer production cropped day-1 in order to estimate the predation impact of C. vicinus , which ranged from 11.6 to more than 100% over time and rotifer species. This shows that relative predation impact can be high not only on species most strongly selected, but also on species which are not selected.

  10. The effect of seasonality on the structure of rotifers in a black-water shallow lake in Central Amazonia.

    PubMed

    Nova, Clarice C; Lopes, Vanessa G; Souza, Leonardo Coimbra E; Kozlowsky-Suzuki, Betina; Pereira, Talita A A; Branco, Christina W C

    2014-09-01

    Rotifers have often been used as indicators of sudden changes in physical and chemical features of the aquatic environment. Such features vary greatly during flood pulse events in small lakes connected to major floodplains. However, few are the studies that investigate the consequences of the flood pulse in rotifer species composition, abundance, richness and diversity, especially in Amazonian lakes. We analyzed samples from a small blackwater lake of an "igarapé" connected permanently to the Negro river, in Central Amazonia. Samples were taken twice a year for two years, comprising flooding and receding periods of the flood pulse. Rotifer abundance increased significantly after draught events, and electrical conductivity and turbidity were intrinsically related to such variation. Species composition also changed from flooding to receding periods. Some taxa, such as Brachionus zahniseri reductus and Lecane remanei were restricted to receding periods, while Brachionus zahniseri, Brachionus gillardi and Lecane proiecta were only present during flooding. A shift in the composition of rotifer families was observed from one period to another, showing the effect of renewing waters of the flood pulse. These results suggest that the flood pulse acts as a driving force and stressing condition, considerably altering rotifer community dynamics, either changing species composition or decreasing abundance. PMID:25119730

  11. Experimental attempt at using Lecane inermis rotifers to control filamentous bacteria Eikelboom Type 0092 in activated sludge.

    PubMed

    Drzewicki, Adam; Kowalska, Ewa; Pajdak-Stós, Agnieszka; Fiałkowska, Edyta; Kocerba-Soroka, Wioleta; Sobczyk, Lukasz; Fyda, Janusz

    2015-03-01

    In laboratory experiments, the authors tested the efficacy of Lecane inermis rotifers in reducing the abundance of filamentous bacteria in activated sludge samples dominated by one filamentous bacterium, Eikelboom Type 0092. The experiment was conducted in three replicates and repeated three times at 1-month intervals. In all repetitions, rotifers were able to significantly reduce the density of bacterial filaments through predation. It was also shown that the influence of rotifers on filament abundance depends on the duration of grazing pressure. The data show that L. inermis, already reported to be effective in reducing the density of Microthrix parvicella, Nostocoida limicola, and Type 021N in activated sludge, can be equally helpful in limiting Type 0092, another troublesome filamentous bacterium found in low-loaded water resource recovery facilities.

  12. Blue-green algae

    MedlinePlus

    “Blue-green algae” describes a large and diverse group of simple, plant-like organisms found in salt water and some large fresh water lakes. Blue-green algae products are used for many conditions, but so ...

  13. Effects of Grazing by Flagellates on Competition for Ammonium between Nitrifying and Heterotrophic Bacteria in Chemostats

    PubMed Central

    Verhagen, Frank J. M.; Laanbroek, Hendrikus J.

    1992-01-01

    The enhanced mineralization of organic nitrogen by bacteriophagous protozoa is thought to favor the nitrification process in soils, in which nitrifying bacteria have to compete with heterotrophic bacteria for the available ammonium. To obtain more insight into this process, the influence of grazing by the bacteriovorous flagellate Adriamonas peritocrescens on the competition for limiting amounts of ammonium between the ammonium-oxidizing species Nitrosomonas europaea and the heterotrophic species Arthrobacter globiformis was studied in the presence of Nitrobacter winogradskyi in continuous cultures at dilution rates of 0.004 and 0.01 h-1. The ammonium concentration in the reservoir was maintained at 2 mM, whereas the glucose concentration was increased stepwise from 0 to 7 mM. A. globiformis won the competition for limiting amounts of ammonium when the glucose concentration in the reservoirs increased, in agreement with previously described experiments in which the flagellates were not included. The numbers of nitrifying bacteria decreased as the numbers of heterotrophic bacteria rose with increasing glucose concentrations. Critical C/N ratios, i.e., ratios between glucose and ammonium in the reservoirs at which no nitrate was found in the culture vessels, of 12.5 and 10.5 were determined at dilution rates of 0.004 and 0.01 h-1, respectively. Below these critical values, coexistence of the competing species was found. The numbers of nitrifying bacteria decreased more in the presence of flagellates than in their absence, presumably by selective predation on the nitrifying bacteria, either in the liquid culture or on the glass wall of the culture vessels. Despite this, the rate of nitrate production did not decrease more in the presence of flagellates than in their absence. This demonstrates that no correlation has to be expected between numbers of nitrifying bacteria and their activity and that a constant nitrification rate per cell cannot be assumed for nitrifying

  14. [Parasitic amoebae and amoebo-flagellates from the Lobosea and heterolobosea classes].

    PubMed

    Sopinina, V A

    1998-01-01

    Different cited evidences on parasitic amoebae and amoebo-flagellates belonging to the Lobosea and Heterolobosea classes (Pages, 1987) have been reviewed. Special attention is paid to various degree of their adaptation to parasitic mode of life, which ranges from a parasitism on a border with commensalism to true parasitism (both facultative and obligatory ones). Besides the coprophilous and commensal species, the number of true parasites among the Lobosea and Heterolobosea classes is comparatively small. In many cases, both facultative and obligatory parasites cause the death of their hosts. Apparently this strongly pronounced pathogenicity of parasitic amoebae and amoebo-flagellates suggest a recent origin of such parasite-host systems. Pathogens of amoebic dysentry, primary amoebic meningoencephalitis and granulomatous amoebic encephalitis are specially considered. In the Russian text-books on a parasitology the information on most of them, except Entamoeba hystolytica, is either totally absent or very scare and out of date. PMID:9813884

  15. Symbioses of flagellates and prokaryotes in the gut of lower termites.

    PubMed

    Ohkuma, Moriya

    2008-07-01

    The microbial community in the gut of phylogenetically lower termites, comprising both flagellated protists and prokaryotes, has fascinated many scientists because of the symbiotic relationships that are responsible for the efficient degradation of lignocellulose. However, the complex nature of this microbial community and the formidable unculturability of most members have hampered detailed microbial studies. Comprehensive phylogenetic descriptions of the community members in the past decade still provide little information about their functions because the community contains diverse novel microbial species. Recent advances in molecular approaches have shed new light on species-specific spatial distributions, particularly the cellular associations of flagellated protists and prokaryotes, their functional interactions and coevolutionary relationships. These advances have gradually unveiled how this symbiotic complex functions to efficiently utilize lignocellulose.

  16. Interactions between marine facultative epiphyte Chlamydomonas sp. (Chlamydomonadales, Chlorophyta) and ceramiaceaen algae (Rhodophyta).

    PubMed

    Klochkova, Tatyana A; Cho, Ga Youn; Boo, Sung Min; Chung, Ki Wha; Kim, Song Ja; Kim, Gwang Hoon

    2008-07-01

    Previously unrecorded marine Chlamydomonas that grew epiphytic on ceramiaceaen algae was collected from the western coast of Korea and isolated into a unialgal culture. The isolate was subjected to 18S rDNA phylogenetic analysis as well as ultrastructure and life cycle studies. It had an affinity with the marine Chlamydomonas species and was less related to freshwater/terrestrial representatives of this genus. It had flagella shorter than the cell body two-layered cell wall with striated outer surface and abundant mucilaginous material beneath the innermost layer and no contractile vacuoles. This alga grew faster in mixed cultures with ceramiaceaen algae rather than in any tested unialgal culture condition; the cells looked healthier and zoosporangia and motile flagellated vegetative cells appeared more often. These results suggested that this Chlamydomonas might be a facultative epiphyte benefiting from its hosts. Several ceramiaceaen algae were tested as host plants. Meanwhile, cell deformation or collapse of the whole thallus was caused to Aglaothamnion byssoides, and preliminary study suggested that a substance released from Chlamydomonas caused the response. This is first report on harmful epiphytic interactions between Chlamydomonas species and red ceramiaceaen algae.

  17. [Spatial structure of communities of heterotrophic flagellates from a sphagnum bog].

    PubMed

    Tikhonenkov, D V; Mazeĭ, Iu A

    2009-01-01

    Spatial distribution pattern of heterotrophic flagellates within a macroscopically homogenous sphagnum parcel of a transitional bog in the southern taiga was studied. Under investigation was horizontal pattern at different scales (1 cm, 10 cm, 1 m, 10 m) and the vertical heterogeneity of the community in the sphagnum quagmire. 105 species and forms of heterotrophic flagellates were revealed. Predominating were euglenids, less abundant are kynetoplastids and cercomonads. The most numerous appeared to be Cryptomonas sp., Heteromita minima, Goniomonas truncata, Protaspis simplex, Bodo designis, B. saltans, Phyllomitus apiculatus, Paraphysomonas sp., Petalomonas minuta. More abundant species were characterized by less patchy distribution than less abundant. At a smaller scale, the community was formed by the species with different degree of patchiness while at larger scales, all the species possess nearly the same distribution pattern. The same number of samples of equal sizes revealed nearly the same species numbers independently of distances between the sample sites, as the samples at each scale differ from each other nearly at the same magnitude. An averaged size of the species aggregations in the community is as large as several centimeters. Such a scale is probably a characteristic size (minimum area) of the community of the sphagnum dwelling heterotrophic flagellates. Rather low environmental heterogeneity within the sphagnum quagmire leads to significant homogeneity of the community at larger scales. Vertical differentiation of the heterotrophic flagellate community within that quagmire appeared to be very unstable with the time. The same species are characterized by different preferences to the depths at different spatial-temporal loci. Specific vertical distributions and community patterns are formed under different local conditions.

  18. Size-selective grazing on bacteria by natural assemblages of estuarine flagellates and ciliates.

    PubMed Central

    Gonzalez, J M; Sherr, E B; Sherr, B F

    1990-01-01

    The small average cell size of in situ bacterioplankton, relative to cultured cells, has been suggested to be at least partly a result of selection of larger-sized cells by bacterivorous protozoa. In this study, we determined the relative rates of uptake of fluorescence-labeled bacteria (FLB), of various cell sizes and cell types, by natural assemblages of flagellates and ciliates in estuarine water. Calculated clearance rates of bacterivorous flagellates had a highly significant, positive relationship with size of FLB, over a range of average biovolume of FLB of 0.03 to 0.08 microns3. Bacterial cell type or cell shape per se did not appear to affect flagellate clearance rates. The dominant size classes of flagellates which ingested all types of FLB were 3- to 4-microns cells. Ciliates also showed a general preference for larger-sized bacteria. However, ciliates ingested a gram-positive enteric bacterium and a marine bacterial isolate at higher rates than they did a similarly sized, gram-negative enteric bacterium or natural bacterioplankton, respectively. From the results of an experiment designed to test whether the addition of a preferentially grazed bacterial strain stimulated clearance rates of natural bacterioplankton FLB by the ciliates, we hypothesized that measured differences in rates of FLB uptake were due instead to differences in effective retention of bacteria by the ciliates. In general, clearance rates for different FLB varied by a factor of 2 to 4. Selective grazing by protozoa of larger bacterioplankton cells, which are generally the cells actively growing or dividing, may in part explain the small average cell size, low frequency of dividing cells, and low growth rates generally observed for assemblages of suspended bacteria. PMID:2107794

  19. Effects of Grazing by Flagellates on Competition for Ammonium between Nitrifying and Heterotrophic Bacteria in Soil Columns

    PubMed Central

    Verhagen, Frank J. M.; Duyts, Hendrik; Laanbroek, Hendrikus J.

    1993-01-01

    The enhanced mineralization of immobilized nitrogen by bacteriophagous protozoa has been thought to favor the nitrification process in soils in which nitrifying bacteria must compete with heterotrophic bacteria for the available ammonium. To obtain more insight into this process, the influence of grazing by the flagellate Adriamonas peritocrescens on the competition for ammonium between the chemolithotrophic species Nitrosomonas europaea and the heterotrophic species Arthrobacter globiformis in the presence of Nitrobacter winogradskyi was studied in soil columns, which were continuously percolated with media containing 5 mM ammonium and different amounts of glucose at a dilution rate of 0.007 h-1 (liquid volumes). A. globiformis won the competition for ammonium. The grazing activities of the flagellates had two prominent effects on the competition between N. europaea and A. globiformis. First, the distribution of ammonium over the profile of the soil columns was more uniform in the presence of flagellates than in their absence. In the absence of flagellates, relatively high amounts of ammonium accumulated in the upper layer (0 to 3 cm), whereas in the underlying layers the ammonium concentrations were low. In the presence of flagellates, however, considerable amounts of ammonium were found in the lower layers, whereas less ammonium accumulated in the upper layer. Second, the potential ammonium-oxidizing activity of N. europaea was stimulated in the presence of flagellates. The numbers of N. europaea at different glucose concentrations in the presence of flagellates were comparable to those in the absence of protozoa. However, in the presence of flagellates, the potential ammonium-oxidizing activities were four to five times greater than those in the absence of protozoa. PMID:16348988

  20. Transmission and ecology of trypanosomatid flagellates of water striders (Hemiptera: Gerridae).

    PubMed

    Tieszen, K L; Molyneux, D H

    1989-01-01

    An investigation of transmission and ecology of the monogenetic trypanosomatids, Blastocrithidia gerridis and Crithidia flexonema, in Gerris is described. Motile free-living flagellates of both species were found in the faeces of Gerris and in the water on which the bugs inhabited. Transmission of both trypanosomatid species occurred from naturally infected wild-caught bugs to flagellate-free laboratory-bred bugs via water. Crithidia flexonema was also transmitted to laboratory-bred bugs after being isolated in culture. Observations of experimentally infected bugs indicate that C. flexonema flagellates are imbibed and pass through the fore- and midgut to the hindgut where they become attached and multiply. There was no evidence to suggest transovarial transmission. In a 3-yr investigation into the prevalence of trypanosomatids in a natural population of adult Gerris odontogaster, it was found that the infection rate varied between 19% and 100%. There was no significant difference in infection rates between females and males. The infection rate peaked for each year in late spring or early summer. The significance of these results is discussed in relation to the ecology and behaviour of Gerris. The results indicate that the infections are maintained in hibernating bugs over winter.

  1. Population structure of Endomicrobia in single host cells of termite gut flagellates (Trichonympha spp.).

    PubMed

    Zheng, Hao; Dietrich, Carsten; Thompson, Claire L; Meuser, Katja; Brune, Andreas

    2015-01-01

    The gut microbiota of many phylogenetically lower termites is dominated by the cellulolytic flagellates of the genus Trichonympha, which are consistently associated with bacterial symbionts. In the case of Endomicrobia, an unusual lineage of endosymbionts of the Elusimicrobia phylum that is also present in other gut flagellates, previous studies have documented strict host specificity, leading to the cospeciation of "Candidatus Endomicrobium trichonymphae" with their respective flagellate hosts. However, it currently remains unclear whether one Trichonympha species is capable of harboring more than one Endomicrobia phylotype. In the present study, we selected single Trichonympha cells from the guts of Zootermopsis nevadensis and Reticulitermes santonensis and characterized their Endomicrobia populations based on internal transcribed spacer (ITS) region sequences. We found that each host cell harbored a homogeneous population of symbionts that were specific to their respective host species, but phylogenetically distinct between each host lineage, corroborating cospeciation being caused by vertical inheritance. The experimental design of the present study also allowed for the identification of an unexpectedly large amount of tag-switching between samples, which indicated that any high-resolution analysis of microbial community structures using the pyrosequencing technique has to be interpreted with great caution.

  2. Unlocking the secrets of multi-flagellated propulsion: drawing insights from Tritrichomonas foetus

    PubMed Central

    Lenaghan, Scott C.; Nwandu-Vincent, Stefan; Reese, Benjamin E.; Zhang, Mingjun

    2014-01-01

    In this work, a high-speed imaging platform and a resistive force theory (RFT) based model were applied to investigate multi-flagellated propulsion, using Tritrichomonas foetus as an example. We discovered that T. foetus has distinct flagellar beating motions for linear swimming and turning, similar to the ‘run and tumble’ strategies observed in bacteria and Chlamydomonas. Quantitative analysis of the motion of each flagellum was achieved by determining the average flagella beat motion for both linear swimming and turning, and using the velocity of the flagella as inputs into the RFT model. The experimental approach was used to calculate the curvature along the length of the flagella throughout each stroke. It was found that the curvatures of the anterior flagella do not decrease monotonically along their lengths, confirming the ciliary waveform of these flagella. Further, the stiffness of the flagella was experimentally measured using nanoindentation, allowing for calculation of the flexural rigidity of T. foetus's flagella, 1.55×10−21 N m2. Finally, using the RFT model, it was discovered that the propulsive force of T. foetus was similar to that of sperm and Chlamydomonas, indicating that multi-flagellated propulsion does not necessarily contribute to greater thrust generation, and may have evolved for greater manoeuvrability or sensing. The results from this study have demonstrated the highly coordinated nature of multi-flagellated propulsion and have provided significant insights into the biology of T. foetus. PMID:24478286

  3. Complex flagellar motions and swimming patterns of the flagellates Paraphysomonas vestita and Pteridomonas danica.

    PubMed

    Christensen-Dalsgaard, Karen K; Fenchel, Tom

    2004-03-01

    Most flagellates with hispid flagella, that is, flagella with rigid filamentous hairs (mastigonemes), swim in the direction of the flagellar wave propagation with an anterior position of the flagellum. Previous analysis was based on planar wave propagation showing that the mastigonemes pull fluid along the flagellar axis. In the present study, we investigate the flagellar motions and swimming patterns for two flagellates with hispid flagella: Paraphysomonas vestita and Pteridomonas danica. Studies were carried out using normal and high-speed video recording, and particles were added to visualize flow around cells generating feeding currents. When swimming or generating flow, P. vestita was able to pull fluid normal to, and not just along, the flagellum, implying the use of the mastigonemes in an as yet un-described way. When the flagellum made contact with food particles, it changed the flagellar waveform so that the particle was fanned towards the ingestion area, suggesting mechano-sensitivity of the mastigonemes. Pteridomonas danica was capable of more complex swimming than previously described for flagellated protists. This was associated with control of the flagellar beat as well as an ability to bend the plane of the flagellar waveform.

  4. Crash of a population of the marine heterotrophic flagellate Cafeteria roenbergensis by viral infection.

    PubMed

    Massana, Ramon; del Campo, Javier; Dinter, Christian; Sommaruga, Ruben

    2007-11-01

    Viruses are known as important mortality agents of marine microorganisms. Most studies focus on bacterial and algal viruses, and few reports exist on viruses infecting marine heterotrophic protists. Here we show results from several incubations initiated with a microbial assemblage from the central Indian Ocean and amended with different amounts of organic matter. Heterotrophic flagellates developed up to 30,000 cells ml(-1) in the most enriched incubation. A 18S rDNA clone library and fluorescent in situ hybridization counts with newly designed probes indicated that the peak was formed by Cafeteria roenbergensis and Caecitellus paraparvulus (90% and 10% of the cells respectively). Both taxa were below detection in the original sample, indicating a strong positive selective bias during the enrichment. During the peak, C. roenbergensis cells were observed with virus-like particles in the cytoplasm, and 4 days later this taxa could not be detected. Transmission electron microscopy confirmed the viral nature of these particles, which were large (280 nm), had double-stranded DNA, and were produced with a burst size of approximately 70. This virus was specific of C. roenbergensis as neither C. paraparvulus that was never seen infected, nor other flagellate taxa that developed in later stages of the incubation, appeared attacked. This is one of the few reports on a heterotrophic flagellate virus and the implications of this finding in the Indian Ocean are discussed.

  5. Distribution and abundance of uncultured heterotrophic flagellates in the world oceans.

    PubMed

    Massana, Ramon; Terrado, Ramon; Forn, Irene; Lovejoy, Connie; Pedrós-Alió, Carlos

    2006-09-01

    Heterotrophic flagellates play fundamental roles in marine ecosystems as picoplankton grazers. This recognized importance contrasts with our ignorance of the taxonomic composition of this functional group, which remains mostly unidentified by microscopical and culturing approaches. Recent molecular marine surveys based on 18S rDNA genes have retrieved many sequences unrelated to cultured organisms and marine stramenopiles were among the first reported uncultured eukaryotes. However, little is known about the organisms corresponding to these sequences. Here we determine the abundance of several marine stramenopile lineages in surface marine waters using molecular probes and fluorescent in situ hybridization. We show that these protists are free-living bacterivorous heterotrophic flagellates. They were widely distributed, occurring in the five world oceans, and accounted for a significant fraction (up to 35%) of heterotrophic flagellates in diverse geographic regions. A single group, MAST-4, represented 9% of cells within this functional assemblage, with the intriguing exception of polar waters where it was absent. MAST-4 cells likely contribute substantially to picoplankton grazing and nutrient re-mineralization in vast areas of the oceans and represent a key eukaryotic group in marine food webs.

  6. Comparison of Rates of Flagellate Bacterivory and Bacterial Production in a Marine Coastal System

    PubMed Central

    Barcina, Isabel; Ayo, Begoña; Unanue, Marian; Egea, Luis; Iriberri, Juan

    1992-01-01

    Protozoan predation on bacteria and bacterioplankton secondary production were simultaneously determined in La Salvaje Beach water during 1990. Protozoan grazing on bacterioplankton was measured from fluorescently labeled bacterium uptake rates; estimates of bacterial secondary production were obtained from [3H]thymidine incorporation rates. Two different conversion factors were used to transform thymidine incorporation rates into bacterial production rates; both of them were specific for La Salvaje Beach and were calculated by using empirical and semitheoretical approaches. The average flagellate predation rate was 14.0 bacteria flagellate-1 h-1; the average population predation rate was 7.35 x 106 bacteria liter-1 h-1. The estimates of bacterial production differed greatly depending on the conversion factor used, and so did the percentages of bacterial production consumed by flagellated protozoa (4.6% when the empirical conversion factor for La Salvaje Beach was used and 113% when the semitheoretical conversion factor specific for this system was used). The ecological implications of each of these values are discussed. PMID:16348819

  7. Sexual species are separated by larger genetic gaps than asexual species in rotifers.

    PubMed

    Tang, Cuong Q; Obertegger, Ulrike; Fontaneto, Diego; Barraclough, Timothy G

    2014-10-01

    Why organisms diversify into discrete species instead of showing a continuum of genotypic and phenotypic forms is an important yet rarely studied question in speciation biology. Does species discreteness come from adaptation to fill discrete niches or from interspecific gaps generated by reproductive isolation? We investigate the importance of reproductive isolation by comparing genetic discreteness, in terms of intra- and interspecific variation, between facultatively sexual monogonont rotifers and obligately asexual bdelloid rotifers. We calculated the age (phylogenetic distance) and average pairwise genetic distance (raw distance) within and among evolutionarily significant units of diversity in six bdelloid clades and seven monogonont clades sampled for 4211 individuals in total. We find that monogonont species are more discrete than bdelloid species with respect to divergence between species but exhibit similar levels of intraspecific variation (species cohesiveness). This pattern arises because bdelloids have diversified into discrete genetic clusters at a faster net rate than monogononts. Although sampling biases or differences in ecology that are independent of sexuality might also affect these patterns, the results are consistent with the hypothesis that bdelloids diversified at a faster rate into less discrete species because their diversification does not depend on the evolution of reproductive isolation.

  8. Maternal age and spine development in a rotifer: ecological implications and evolution.

    PubMed

    Gilbert, John J; McPeek, Mark A

    2013-10-01

    Brachionus calyciflorus typically develops long, defensive spines only in response to a kairomone from the predatory rotifer, Asplanchna. However, in the absence of any environmental induction, females of some clones produce daughters with increasingly long spines as they age; late-born individuals can have posterolateral spines as long as those induced by Asplanchna: up to 50% or more of body length. Here, we construct a model using data from life-table and predator-prey experiments to assess how this maternal-age effect can influence the distribution of spine lengths in reproducing populations and provide defense against Asplanchna predation. When Asplanchna is absent, the frequency of individuals with late birth orders rapidly becomes extremely low; thus, any cost associated with the production of long-spined individuals is minimal. When Asplanchna is present at densities too low for spine induction, and preys selectively on individuals with no or short posterolateral spines, the frequency of long-spined individuals rapidly increases until a stable birth-order structure is reached. As a result, mortality from Asplanchna predation is greatly reduced. The pronounced and novel birth-order effect in this rotifer appears to be an effective bet-hedging strategy to limit predation by Asplanchna when its kairomone induces no or less than maximal spine development.

  9. SEXUAL SPECIES ARE SEPARATED BY LARGER GENETIC GAPS THAN ASEXUAL SPECIES IN ROTIFERS

    PubMed Central

    Tang, Cuong Q; Obertegger, Ulrike; Fontaneto, Diego; Barraclough, Timothy G

    2014-01-01

    Why organisms diversify into discrete species instead of showing a continuum of genotypic and phenotypic forms is an important yet rarely studied question in speciation biology. Does species discreteness come from adaptation to fill discrete niches or from interspecific gaps generated by reproductive isolation? We investigate the importance of reproductive isolation by comparing genetic discreteness, in terms of intra- and interspecific variation, between facultatively sexual monogonont rotifers and obligately asexual bdelloid rotifers. We calculated the age (phylogenetic distance) and average pairwise genetic distance (raw distance) within and among evolutionarily significant units of diversity in six bdelloid clades and seven monogonont clades sampled for 4211 individuals in total. We find that monogonont species are more discrete than bdelloid species with respect to divergence between species but exhibit similar levels of intraspecific variation (species cohesiveness). This pattern arises because bdelloids have diversified into discrete genetic clusters at a faster net rate than monogononts. Although sampling biases or differences in ecology that are independent of sexuality might also affect these patterns, the results are consistent with the hypothesis that bdelloids diversified at a faster rate into less discrete species because their diversification does not depend on the evolution of reproductive isolation. PMID:24975991

  10. Clocks in algae.

    PubMed

    Noordally, Zeenat B; Millar, Andrew J

    2015-01-20

    As major contributors to global oxygen levels and producers of fatty acids, carotenoids, sterols, and phycocolloids, algae have significant ecological and commercial roles. Early algal models have contributed much to our understanding of circadian clocks at physiological and biochemical levels. The genetic and molecular approaches that identified clock components in other taxa have not been as widely applied to algae. We review results from seven species: the chlorophytes Chlamydomonas reinhardtii, Ostreococcus tauri, and Acetabularia spp.; the dinoflagellates Lingulodinium polyedrum and Symbiodinium spp.; the euglenozoa Euglena gracilis; and the red alga Cyanidioschyzon merolae. The relative simplicity, experimental tractability, and ecological and evolutionary diversity of algal systems may now make them particularly useful in integrating quantitative data from "omic" technologies (e.g., genomics, transcriptomics, metabolomics, and proteomics) with computational and mathematical methods.

  11. Morphology and ultrastructure of the freshwater rotifer Brachionus bidentatus (Monogononta: Brachionidae) using scanning and transmission electron microscopy.

    PubMed

    Guerrero-Jiménez, Gerardo; Zavala-Padilla, Guadalupe; Silva-Briano, Marcelo; Rico-Martínez, Roberto

    2013-12-01

    The study of sexual reproductive behavior supported by ultrastructural evidence is important in rotifers to describe differences among potential cryptic species. In this research, the morphology of the rotifer Brachionus bidentatus is described at the ultrastructural level, using electronic microscopy, together with a brief description and discussion of its sexual reproductive behavior. The characteristics of the (a) male, (b) the female, (c) the sexual egg or cyst, (d) the partenogenic egg, (e) the no-fecundated sexual egg (male egg), and (f) the trophi, were described. Another part of this research is dedicated to the ultrastructure of the sex cells of the male rotifer B. bidentatus. Samples were obtained from La Punta pond in Cosio, Aguascalientes, Mexico (22 degrees 08' N - 102 degrees 24' W), and a culture was maintained in the laboratory. Fifty organisms, from different stages of the rotifer Brachionus bidentatus, were fixed in Formol at 4% and then prepared; besides, for the trophi, 25 female rotifer Brachionus bidentatus were prepared for observation in a JEOL 5900 LV scanning electronic microscope. In addition, for the observation of male sex cells, 500 males of Brachionus bidentatus were isolated, fixed and observed in a JEOL 1010 transmission microscope. Females of B. bidentatus in laboratory cultures had a lifespan of five days (mean+one SD = 4.69 +/- 0.48; N=13), and produced 4.5 +/- 3.67 (N=6) parthenogenetic eggs during such lifespan. In the case of non-fertilized sexual eggs, they produced up to 18 eggs (mean+one SD = 13 +/- 4.93; N=7). Sexual females produced a single cyst on average (mean +/- one SD = I +/- 0; N=20). For the sexual cycle, the time of copulation between male and female ranged from 10 to 40 seconds (mean +/- one SD = 17.33 +/- 10.55, N=7). The spermatozoa are composed of a celular body and a flagellum, the size of the body is of 300 nm while the flagellum measures 1 700nm. The rods have a double membrane. Their mean length is almost

  12. Determination of trace elements in freshwater rotifers and ciliates by total reflection X-ray fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Woelfl, S.; Óvári, M.; Nimptsch, J.; Neu, T. R.; Mages, M.

    2016-02-01

    Element determination in plankton is important for the assessment of metal contamination of aquatic environments. Until recently, it has been difficult to determine elemental content in rotifers or ciliates derived from natural plankton samples because of the difficulty in handling and separation of these fragile organisms. The aim of this study was to evaluate methods for separation of rotifers and large ciliates from natural plankton samples (μg range dry weight) and subsequent analysis of their elemental content using total-reflection X-ray fluorescence spectrometry (TXRF). Plankton samples were collected from different aquatic environments (three lakes, one river) in Chile, Argentina and Hungary. From one to eighty specimens of five rotifer species (Brachionus calyciflorus, Brachionus falcatus, Asplanchna sieboldii, Asplanchna sp., Philodina sp.) and four to twelve specimens of one large ciliate (Stentor amethystinus) were prepared according to the dry method originally developed for microcrustaceans, and analysed by TRXF following in situ microdigestion. Our results demonstrated that it possible to process these small and fragile organisms (individual dry mass: 0.17-9.39 μg ind- 1) via careful washing and preparation procedures. We found species-dependent differences of the element mass fractions for some of the elements studied (Cr, Mn, Fe, Ni, Cu, Zn, As, Pb), especially for Cu, Fe and Mn. One large rotifer species (A. sieboldii) also showed a negative correlation between individual dry weight and the element content for Pb, Ni and Cr. We conclude that our application of the in situ microdigestion-TRXF method is suitable even for rotifers and ciliates, greatly expanding the possibilities for use of plankton in biomonitoring of metal contamination in aquatic environments.

  13. Seasonal changes in the body size of two rotifer species living in activated sludge follow the Temperature-Size Rule

    PubMed Central

    Kiełbasa, Anna; Walczyńska, Aleksandra; Fiałkowska, Edyta; Pajdak-Stós, Agnieszka; Kozłowski, Jan

    2014-01-01

    Temperature-Size Rule (TSR) is a phenotypic body size response of ectotherms to changing temperature. It is known from the laboratory studies, but seasonal patterns in the field were not studied so far. We examined the body size changes in time of rotifers inhabiting activated sludge. We hypothesize that temperature is the most influencing parameter in sludge environment, leading sludge rotifers to seasonally change their body size according to TSR, and that oxygen content also induces the size response. The presence of TSR in Lecane inermis rotifer was tested in a laboratory study with two temperature and two food-type treatments. The effect of interaction between temperature and food was significant; L. inermis followed TSR in one food type only. The seasonal variability in the body sizes of the rotifers L. inermis and Cephalodella gracilis was estimated by monthly sampling and analyzed by multiple regression, in relation to the sludge parameters selected as the most influential by multivariate analysis, and predicted to alter rotifer body size (temperature and oxygen). L. inermis varied significantly in size throughout the year, and this variability is explained by temperature as predicted by the TSR, but not by oxygen availability. C. gracilis also varied in size, though this variability was explained by both temperature and oxygen. We suggest that sludge age acts as a mortality factor in activated sludge. It may have a seasonal effect on the body size of L. inermis and modify a possible effect of oxygen. Activated sludge habitat is driven by both biological processes and human regulation, yet its resident organisms follow general evolutionary rule as they do in other biological systems. The interspecific response patterns differ, revealing the importance of taking species-specific properties into account. Our findings are applicable to sludge properties enhancement through optimizing the conditions for its biological component. PMID:25558362

  14. Seasonal changes in the body size of two rotifer species living in activated sludge follow the Temperature-Size Rule.

    PubMed

    Kiełbasa, Anna; Walczyńska, Aleksandra; Fiałkowska, Edyta; Pajdak-Stós, Agnieszka; Kozłowski, Jan

    2014-12-01

    Temperature-Size Rule (TSR) is a phenotypic body size response of ectotherms to changing temperature. It is known from the laboratory studies, but seasonal patterns in the field were not studied so far. We examined the body size changes in time of rotifers inhabiting activated sludge. We hypothesize that temperature is the most influencing parameter in sludge environment, leading sludge rotifers to seasonally change their body size according to TSR, and that oxygen content also induces the size response. The presence of TSR in Lecane inermis rotifer was tested in a laboratory study with two temperature and two food-type treatments. The effect of interaction between temperature and food was significant; L. inermis followed TSR in one food type only. The seasonal variability in the body sizes of the rotifers L. inermis and Cephalodella gracilis was estimated by monthly sampling and analyzed by multiple regression, in relation to the sludge parameters selected as the most influential by multivariate analysis, and predicted to alter rotifer body size (temperature and oxygen). L. inermis varied significantly in size throughout the year, and this variability is explained by temperature as predicted by the TSR, but not by oxygen availability. C. gracilis also varied in size, though this variability was explained by both temperature and oxygen. We suggest that sludge age acts as a mortality factor in activated sludge. It may have a seasonal effect on the body size of L. inermis and modify a possible effect of oxygen. Activated sludge habitat is driven by both biological processes and human regulation, yet its resident organisms follow general evolutionary rule as they do in other biological systems. The interspecific response patterns differ, revealing the importance of taking species-specific properties into account. Our findings are applicable to sludge properties enhancement through optimizing the conditions for its biological component. PMID:25558362

  15. Starvation-Induced Changes in Motility, Chemotaxis, and Flagellation of Rhizobium meliloti†

    PubMed Central

    Wei, Xueming; Bauer, Wolfgang D.

    1998-01-01

    The changes in motility, chemotactic responsiveness, and flagellation of Rhizobium meliloti RMB7201, L5-30, and JJ1c10 were analyzed after transfer of the bacteria to buffer with no available C, N, or phosphate. Cells of these three strains remained viable for weeks after transfer to starvation buffer (SB) but lost all motility within just 8 to 72 h after transfer to SB. The rates of motility loss differed by severalfold among the strains. Each strain showed a transient, two- to sixfold increase in chemotactic responsiveness toward glutamine within a few hours after transfer to SB, even though motility dropped substantially during the same period. Strains L5-30 and JJ1c10 also showed increased responsiveness to the nonmetabolizable chemoattractant cycloleucine. Cycloleucine partially restored the motility of starving cells when added after transfer and prevented the loss of motility when included in the SB used for initial suspension of the cells. Thus, interactions between chemoattractants and their receptors appear to affect the regulation of motility in response to starvation independently of nutrient or energy source availability. Electron microscopic observations revealed that R. meliloti cells lost flagella and flagellar integrity during starvation, but not as fast, nor to such a great extent, as the cells lost motility. Even after prolonged starvation, when none of the cells were actively motile, about one-third to one-half of the initially flagellated cells retained some flagella. Inactivation of flagellar motors therefore appears to be a rapid and important response of R. meliloti to starvation conditions. Flagellar-motor inactivation was at least partially reversible by addition of either cycloleucine or glucose. During starvation, some cells appeared to retain normal flagellation, normal motor activity, or both for relatively long periods while other cells rapidly lost flagella, motor activity, or both, indicating that starvation-induced regulation of

  16. Character of cellulase activity in the guts of flagellate-free termites with different feeding habits.

    PubMed

    Li, Zhi-Qiang; Liu, Bing-Rong; Zeng, Wen-Hui; Xiao, Wei-Liang; Li, Qiu-Jian; Zhong, Jun-Hong

    2013-01-01

    Cellulose digestion in termites (Isoptera) is highly important for ecological reasons and applications in biofuel conversion. The speciose Termitidae family has lost flagellates in the hindgut and developed diverse feeding habits. To address the response of cellulase activity to the differentiation of feeding habits, a comparative study of the activity and distribution of composite cellulases, endo-β-1,4-glucanase, and β-glucosidase was performed in seven common flagellate-free termites with three feeding habits: the humus-feeding termites Sinocapritermes mushae (Oshima et Maki), Malaysiocapritermes zhangfengensis Zhu, Yang et Huang and Pericapritermes jiangtsekiangensis (Kemner); the fungus-growing termites Macrotermes barneyi Light and Odontotermes formosanus (Shiraki); and the wood-feeding termites Nasutitermes parvonasutus (Shiraki) and Havilanditermes orthonasus (Tsai et Chen). The results showed that in diverse feeding groups, the wood-feeding group had the highest total composite cellulase and endo-β-1,4-glucanase activities, while the fungus-growing group had the highest β-glucosidase activity. In terms of the distribution of cellulase activity in the alimentary canals, the cellulase activities in wood-feeding termites were concentrated in the midgut, but there was no significant difference between all gut segments in humus-feeding termites. As for the fungus-growing termites, the main site of composite cellulase activity was in the midgut. The endo-β-1,4-glucanase activity was restricted to the midgut, but the primary site of β-glucosidase activity was in the foregut and the midgut (Mac. barneyi). The functions of the gut segments apparently differentiated between feeding groups. The results suggest that the differentiation of feeding habits in flagellate-free termites was characterized by the distribution of cellulases in the gut rather than by variations in cellulase activity.

  17. Impact of three phthalate esters on the sexual reproduction of the Monogonont rotifer, Brachionus calyciflorus.

    PubMed

    Cruciani, V; Iovine, C; Thomé, J-P; Joaquim-Justo, C

    2016-01-01

    Phthalate esters are widespread contaminants that can cause endocrine disruption in vertebrates. Studies showed that molecules with hormonal activities in vertebrates and invertebrates can affect asexual and sexual reproduction in rotifers. We investigated the impact of di-hexylethyl phthalate (DEHP), di-butyl phthalate (DBP) and butylbenzyl phthalate (BBP), on the asexual and sexual reproduction of the freshwater monogonont rotifer Brachionus calyciflorus in order to determine a potential environmental risk for sexual reproduction. We observed that DEHP has no significant impact on both asexual and sexual reproduction up to 2 mg/L. DBP has a positive effect on asexual reproduction at concentrations from 0.05 to 1 mg/L, but depresses it at 2 mg/L. Sexual reproduction is only affected at 2 mg/L and the impact observed is negative. BBP displayed a negative impact on both asexual and sexual reproduction at 1 and 2 mg/L. However we showed that the impacts of BBP on mixis and fertilization rates observed are due to the decrease in population growth rates at these concentrations and not to a direct impact of BBP on the mixis and the fertilization processes. Our results show that sexual reproduction in B. calyciflorus is not more sensitive than asexual reproduction to any of the substances tested which indicates the mode of action of these molecules is related to general toxicity and not to an interference with potential endocrine regulation of sexual reproduction. Comparison of effect concentrations and surface water contamination by phthalate esters suggests these compounds do not constitute a risk for primary consumers in these environments. PMID:26666431

  18. Long-Term Competitive Dynamics of Two Cryptic Rotifer Species: Diapause and Fluctuating Conditions

    PubMed Central

    Gabaldón, Carmen; Carmona, María José; Montero-Pau, Javier; Serra, Manuel

    2015-01-01

    Life-history traits may have an important role in promoting species coexistence. However, the complexity of certain life cycles makes it difficult to draw conclusions about the conditions for coexistence or exclusion based on the study of short-term competitive dynamics. Brachionus plicatilis and B. manjavacasare two cryptic rotifer species co-occurring in many lakes on the Iberian Peninsula. They have a complex life cycle in which cyclical parthenogenesis occurs with diapausing stages being the result of sexual reproduction. B. plicatilis and B. manjavacasare identical in morphology and size, their biotic niches are broadly overlapping, and they have similar competitive abilities. However, the species differ in life-history traits involving sexual reproduction and diapause, and respond differently to salinity and temperature. As in the case of certain other species that are extremely similar in morphology, a fluctuating environment are considered to be important for their coexistence. We studied the long-term competitive dynamics of B. plicatilis and B. manjavacas under different salinity regimes (constant and fluctuating). Moreover, we focused on the dynamics of the diapausing egg bank to explore how the outcome of the entire life cycle of these rotifers can work to mediate stable coexistence. We demonstrated that these species do not coexist under constant-salinity environment, as the outcome of competition is affected by the level of salinity—at low salinity, B. plicatilis excluded B. manjavacas, and the opposite outcome occurred at high salinity. Competitive dynamics under fluctuating salinity showed that the dominance of one species over the other also tended to fluctuate. The duration of co-occurrence of these species was favoured by salinity fluctuation and perhaps by the existence of a diapausing egg bank. Stable coexistence was not found in our system, which suggests that other factors or other salinity fluctuation patterns might act as stabilizing

  19. Long-term competitive dynamics of two cryptic rotifer species: diapause and fluctuating conditions.

    PubMed

    Gabaldón, Carmen; Carmona, María José; Montero-Pau, Javier; Serra, Manuel

    2015-01-01

    Life-history traits may have an important role in promoting species coexistence. However, the complexity of certain life cycles makes it difficult to draw conclusions about the conditions for coexistence or exclusion based on the study of short-term competitive dynamics. Brachionus plicatilis and B. manjavacasare two cryptic rotifer species co-occurring in many lakes on the Iberian Peninsula. They have a complex life cycle in which cyclical parthenogenesis occurs with diapausing stages being the result of sexual reproduction. B. plicatilis and B. manjavacasare identical in morphology and size, their biotic niches are broadly overlapping, and they have similar competitive abilities. However, the species differ in life-history traits involving sexual reproduction and diapause, and respond differently to salinity and temperature. As in the case of certain other species that are extremely similar in morphology, a fluctuating environment are considered to be important for their coexistence. We studied the long-term competitive dynamics of B. plicatilis and B. manjavacas under different salinity regimes (constant and fluctuating). Moreover, we focused on the dynamics of the diapausing egg bank to explore how the outcome of the entire life cycle of these rotifers can work to mediate stable coexistence. We demonstrated that these species do not coexist under constant-salinity environment, as the outcome of competition is affected by the level of salinity-at low salinity, B. plicatilis excluded B. manjavacas, and the opposite outcome occurred at high salinity. Competitive dynamics under fluctuating salinity showed that the dominance of one species over the other also tended to fluctuate. The duration of co-occurrence of these species was favoured by salinity fluctuation and perhaps by the existence of a diapausing egg bank. Stable coexistence was not found in our system, which suggests that other factors or other salinity fluctuation patterns might act as stabilizing

  20. Impact of three phthalate esters on the sexual reproduction of the Monogonont rotifer, Brachionus calyciflorus.

    PubMed

    Cruciani, V; Iovine, C; Thomé, J-P; Joaquim-Justo, C

    2016-01-01

    Phthalate esters are widespread contaminants that can cause endocrine disruption in vertebrates. Studies showed that molecules with hormonal activities in vertebrates and invertebrates can affect asexual and sexual reproduction in rotifers. We investigated the impact of di-hexylethyl phthalate (DEHP), di-butyl phthalate (DBP) and butylbenzyl phthalate (BBP), on the asexual and sexual reproduction of the freshwater monogonont rotifer Brachionus calyciflorus in order to determine a potential environmental risk for sexual reproduction. We observed that DEHP has no significant impact on both asexual and sexual reproduction up to 2 mg/L. DBP has a positive effect on asexual reproduction at concentrations from 0.05 to 1 mg/L, but depresses it at 2 mg/L. Sexual reproduction is only affected at 2 mg/L and the impact observed is negative. BBP displayed a negative impact on both asexual and sexual reproduction at 1 and 2 mg/L. However we showed that the impacts of BBP on mixis and fertilization rates observed are due to the decrease in population growth rates at these concentrations and not to a direct impact of BBP on the mixis and the fertilization processes. Our results show that sexual reproduction in B. calyciflorus is not more sensitive than asexual reproduction to any of the substances tested which indicates the mode of action of these molecules is related to general toxicity and not to an interference with potential endocrine regulation of sexual reproduction. Comparison of effect concentrations and surface water contamination by phthalate esters suggests these compounds do not constitute a risk for primary consumers in these environments.

  1. Ethidium bromide: a fast fluorescent staining procedure for the detection of symbiotic partnership of flagellates and prokaryotes.

    PubMed

    Fröhlich, J; König, H

    1999-03-01

    The hindgut of 'lower' termites harbors a dense population of flagellates and bacteria. The flagellates possess ecto- and endosymbiotic prokaryotes. Most of them are hardly visible in the phase contrast microscope. Staining with the DNA-intercalating agent ethidium bromide visualizes the nuclei of the flagellates as well as the ecto- and endosymbiotic bacteria as red objects. Furthermore, it is possible to distinguish between endosymbiotic methanogens and other bacteria. Following UV excitation, the blue-green autofluorescence of the methanogenic bacteria eclipses the red fluorescence light of the intercalated ethidium bromide. The dye facilitates the observation of symbiotic bacteria and helps identify the number, shape, localization, and dividing status of the nuclei. Thus, it is a powerful tool for the examination of microorganisms in complex habitats, which are rich in strongly autofluorescent material, like wood. PMID:10192044

  2. [The cell biology of amebas and ameba-flagellates--parasites of man and animals].

    PubMed

    Sopina, V A

    1997-01-01

    The majority of parasitic amoebae and amoeba-flagellates are facultative parasites of animals and humans and only a few of them are obligate parasites (see reviews: Sopina, 1997; Visvesvara, Stehr-Green, 1990). Among the latter Entamoeba histolytica and among the former Naegleria fowleri and several species of Acanthamoeba are most dangerous for humans. It is still unclear whether Balamuthia mandrillaris, pathogenic for monkeys and humans, may be either obligate or facultative parasite (Visvesvara et al., 1993). Endolimax nana and Iodamoeba butschlii are commensals of humans and some animals. This review is devoted to cell biology of the above genera to provide a better understanding of cell-biological aspects of interrelations between these parasites and their hosts. In the Russian text-books on medical and veterinary parasitology these parasitic protozoa have never been regarded in terms of cell biology, and the available information seems to become out of date. This review is aimed to fill these gaps. Evidence on the ultrastructure of the above parasites, in particular that of their mitotic chromosomes, mechanisms of attachment to substratum of many of these, of locomotion and endocytosis, is provided and discussed in addition to the problem of differentiation of Naegleria amoebae into flagellates.

  3. Toxicity assessment of a common laundry detergent using the freshwater flagellate Euglena gracilis.

    PubMed

    Azizullah, Azizullah; Richter, Peter; Häder, Donat-Peter

    2011-09-01

    Synthetic detergents are among the commonly used chemicals in everyday life. Detergents, reaching aquatic environments through domestic and municipal wastewater, can cause many different effects in aquatic organisms. The present study was aimed at the toxicity evaluation of a commonly used laundry detergent, Ariel, using the freshwater flagellate Euglena gracilis as a biotest organism. Different parameters of the flagellate like motility, swimming velocity, cell shape, gravitactic orientation, photosynthesis and concentration of light harvesting pigments were used as end points for the toxicity assessment. No Observed Effect Concentration (NOEC) and EC(50) values were calculated for the end point parameters at four different incubation times, i.e. 0, 6, 24 and 72 h. After 72 h incubation, swimming velocity of the cells was found to be the most sensitive parameter giving NOEC and EC(50) values of 10.8 and 34 mg L(-1), respectively. After 72 h exposure to the detergent, chlorophyll a and total carotenoids were significantly decreased in cultures treated with Ariel at concentrations of 50 mg L(-1) and above while chlorophyll b significantly decreased at concentrations above 750 mg L(-1). The maximum inhibitory effect on the quantum yield of photosystem II was observed after 24 h exposure and thereafter a recovery trend was observed. Motility, gravitaxis and cell shape were strongly impaired immediately upon exposure to the detergent, but with increasing exposure time these parameters showed acclimatization to the stress and thus the NOEC values obtained after 72 h were higher than those immediately after exposure.

  4. Flagellar regeneration in the scaly green flagellate Tetraselmis striata (Prasinophyceae): regeneration kinetics and effect of inhibitors

    NASA Astrophysics Data System (ADS)

    Reize, I. B.; Melkonian, M.

    1987-06-01

    Flagellar regeneration after experimental amputation was studied in synchronized axenic cultures of the scaly green flagellate Tetraselmis striata (Prasinophyceae). After removal of flagella by mechanical shearing, 95% of the cells regrow all four flagella (incl. the scaly covering) to nearly full length with a linear velocity of 50 nm/min under standard conditions. Flagellar regeneration is independent of photosynthesis (no effect of DCMU; the same regeneration rate in the light or in the dark), but depends on de novo protein synthesis: cycloheximide at a low concentration (0.35 μM) blocks flagellar regeneration reversibly. No pool of flagellar precursors appears to be present throughout the flagellated phase of the cell cycle. A transient pool of flagellar precursors, sufficient to generate 2.5 μm of flagellar length, however, develops during flagellar regeneration. Tunicamycin (2 μg/ml) inhibits flagellar regeneration only after a second flagellar amputation, when flagella reach only one third the length of the control. Flagellar regeneration in T. striata differs considerably from that of Chlamydomonas reinhardtii and represents an excellent model system for the study of synchronous Golgi apparatus (GA) activation, and transport and exocytosis of GA-derived macromolecules (scales).

  5. Comparative toxicity of the pesticides carbofuran and malathion to the freshwater flagellate Euglena gracilis.

    PubMed

    Azizullah, Azizullah; Richter, Peter; Häder, Donat-Peter

    2011-08-01

    Pesticides are toxic chemicals used for agricultural as well as non-agricultural purposes. The toxicity of pesticides does not remain limited to the site of application but they also cause toxicity to non-target organisms in terrestrial as well as in aquatic environments. This study discusses the comparative toxicity of a carbamate (carbofuran) and an organophosphorus (malathion) pesticide to the freshwater flagellate Euglena gracilis during short- and long-term exposures. To evaluate the toxicity of the pesticides, different parameters of the flagellate, like cell density, motility, swimming velocity, cell shape, gravitactic orientation, photosynthetic efficiency, and concentration of light harvesting pigments, were used as end points. Carbofuran was found to be more toxic to E. gracilis than malathion and adversely affected almost all the tested parameters in short- and long-term experiments. The only significant adverse effect by malathion could be demonstrated on the swimming velocity of cells in short-term experiments. The adverse effects of the pesticides were more pronounced during short-term than during long-term exposure.

  6. Genetic evidence for a mitochondriate ancestry in the 'amitochondriate' flagellate Trimastix pyriformis.

    PubMed

    Hampl, Vladimir; Silberman, Jeffrey D; Stechmann, Alexandra; Diaz-Triviño, Sara; Johnson, Patricia J; Roger, Andrew J

    2008-01-01

    Most modern eukaryotes diverged from a common ancestor that contained the alpha-proteobacterial endosymbiont that gave rise to mitochondria. The 'amitochondriate' anaerobic protist parasites that have been studied to date, such as Giardia and Trichomonas harbor mitochondrion-related organelles, such as mitosomes or hydrogenosomes. Yet there is one remaining group of mitochondrion-lacking flagellates known as the Preaxostyla that could represent a primitive 'pre-mitochondrial' lineage of eukaryotes. To test this hypothesis, we conducted an expressed sequence tag (EST) survey on the preaxostylid flagellate Trimastix pyriformis, a poorly-studied free-living anaerobe. Among the ESTs we detected 19 proteins that, in other eukaryotes, typically function in mitochondria, hydrogenosomes or mitosomes, 12 of which are found exclusively within these organelles. Interestingly, one of the proteins, aconitase, functions in the tricarboxylic acid cycle typical of aerobic mitochondria, whereas others, such as pyruvate:ferredoxin oxidoreductase and [FeFe] hydrogenase, are characteristic of anaerobic hydrogenosomes. Since Trimastix retains genetic evidence of a mitochondriate ancestry, we can now say definitively that all known living eukaryote lineages descend from a common ancestor that had mitochondria. PMID:18167542

  7. Origin of the algae.

    PubMed

    Perasso, R; Baroin, A; Qu, L H; Bachellerie, J P; Adoutte, A

    1989-05-11

    Eukaryotic algae are traditionally separated into three broad divisions: the rhodophytes, the chromophytes and the chlorophytes. The evolutionary relationships between these groups, their links with other eukaryotes and with other photosynthetic groups, such as euglenophytes and cryptophytes, have been the subject of much debate and speculation. Here we analyse partial sequences of the large (28S) cytoplasmic ribosomal RNA from ten new species of protists belonging to various groups of unicellular algae. By combining them with the homologous sequences from 14 other unicellular and multicellular eukaryotes, we show that rhodophytes, chromophytes and chlorophytes emerge as three distinct groups late among eukaryotes, that is, close to the metazoa-metaphytes radiation. This implies a relatively late occurrence of eukaryotic photosynthetic symbiosis. We also provide details of intra- and inter-phyla relationships.

  8. Genomics of Volvocine Algae

    PubMed Central

    Umen, James G.; Olson, Bradley J.S.C.

    2015-01-01

    Volvocine algae are a group of chlorophytes that together comprise a unique model for evolutionary and developmental biology. The species Chlamydomonas reinhardtii and Volvox carteri represent extremes in morphological diversity within the Volvocine clade. Chlamydomonas is unicellular and reflects the ancestral state of the group, while Volvox is multicellular and has evolved numerous innovations including germ-soma differentiation, sexual dimorphism, and complex morphogenetic patterning. The Chlamydomonas genome sequence has shed light on several areas of eukaryotic cell biology, metabolism and evolution, while the Volvox genome sequence has enabled a comparison with Chlamydomonas that reveals some of the underlying changes that enabled its transition to multicellularity, but also underscores the subtlety of this transition. Many of the tools and resources are in place to further develop Volvocine algae as a model for evolutionary genomics. PMID:25883411

  9. Molecular phylogeny of methanogens associated with flagellated protists in the gut and with the gut epithelium of termites.

    PubMed

    Tokura; Ohkuma; Kudo

    2000-09-01

    The molecular phylogeny of methanogenic archaea associated with the flagellated protist species Dinenympha and Microjoenia in the gut of termites, Reticulitermes speratus and Hodotermopsis sjoestedti, and those attached to the gut epithelium was examined based on PCR-amplified small-subunit ribosomal RNA genes. The sequences identified were classified into six groups within the genus Methanobrevibacter, including groups of yet uncharacterized novel species. Closely related methanogens were shared between Microjoenia and some Dinenympha cells in each termite. The methanogens harbored by the flagellates were phylogenetically different from the methanogens associated with the gut epithelium, suggesting that distinct methanogen species showed distinct spatial distributions in the termite gut.

  10. Comparison of acute toxicity of process chemicals used in the oil refinery industry, tested with the diatom Chaetoceros gracilis, the flagellate Isochrysis galbana, and the zebra fish, Brachydanio rerio

    SciTech Connect

    Roseth, S.; Edvardsson, T.; Botten, T.M.; Fuglestad, J.; Fonnum, F.; Stenersen, J.

    1996-07-01

    Chemicals under the trade names Nalco 537-DA, Nalco 625, Nalco 7607, Nalco 5165, Ivamin, and technical monoethanolamine are used extensively in the oil refinery industry. Aquatic toxicity tests were conducted using zebra fish fry (Brachydanio rerio) and the unicellular algae Isochrysis galbana (a flagellate) and Chaetoceros gracilis (a diatom). Inhibition of cell division, chlorophyll content, and {sup 14}CO{sub 2} uptake in the algae were sensitive end points. The effective concentrations (EC50s) of growth inhibition were 0.1 mg/L (Ivamin; I. galbana), 0.8 mg/L (Nalco 7607; I. galbana), 6 mg/L (Nalco 625; I. galbana), 10 mg/L (Nalco 5165; C. gracilis), and 15 mg/L (Nalco 537-DA; C. gracilis). The lethal concentrations (LC50s) (96 h) toward zebra fish fry was 1 mg/L for Nalco 7607, 6.5 mg/L for Nalco 537-DA, 7.1 mg/L for Nalco 625, and 20 mg/L for Ivamin 803. Monoethanolamine had an LC50 higher than 5,000 mg/L. Nalco 5165 was not tested on fish fry. The heartbeat frequency of fish embryos was reduced by 2.5 mg/L Nalco 537-DA, but this was an insensitive end point for the other chemicals.

  11. Rotifer dynamics in three shallow lakes from the Salado river watershed (Argentina): the potential modulating role of incident solar radiation.

    PubMed

    Diovisalvi, Nadia; Rennella, Armando M; Zagarese, Horacio E

    2015-11-01

    In turbid Pampean lakes, incident solar radiation is a major driver of plankton seasonal dynamics. Higher light availability in summer translates into higher primary production, and therefore more food for zooplankton grazers. However, experimental evidence suggests that food produced under the high irradiance conditions prevailing in summer are less suitable to sustain rotifer population growth than that produced under the lower irradiance conditions typical of winter. Here, we analysed time series datasets corresponding to three shallow lakes from the Salado river watershed. This analysis provided evidence for similar seasonal patterns of rotifer relative abundance over a large geographic area. In addition, we performed life table experiments to test the hypothesis that natural seston produced in winter could sustain higher population growth rates than seston produced in summer. We suggest that the natural seasonal changes in temperature and food generate successive time windows, which may be capitalized by the different grazer species, resulting in predictable phenology of grazer populations.

  12. Whole transcriptome analysis of the monogonont rotifer Brachionus koreanus provides molecular resources for developing biomarkers of carbohydrate metabolism.

    PubMed

    Lee, Bo-Young; Kim, Hui-Su; Hwang, Dae-Sik; Won, Eun-Ji; Choi, Beom-Soon; Choi, Ik-Young; Park, Heum Gi; Rhee, Jae-Sung; Lee, Jae-Seong

    2015-06-01

    Rotifers (phylum Rotifera) are the most common non-arthropod animal. Species in the monogonont rotifer Brachionus are widely distributed in coastal areas and play an important role in aquatic food webs as secondary producers. Brachionus koreanus is currently being developed as a model system for ecotoxicological research. We sequenced the whole transcriptome of B. koreanus using RNA-seq technology. De novo sequence assembly by Trinity integrated with TransDecoder produced 36,918 contigs, including putative alternatively spliced variants. A total of 13,784 genes were identified based on Blast analysis. KEGG pathway analysis detected transcripts annotated as coding for enzymes involved in metabolic pathways, the immune system, translation, and signal transduction. Most identified enzymes and pathways were involved in carbohydrate metabolism, such as the tricarboxylic acid (TCA) cycle and glycolysis. We anticipate that the availability of whole transcriptome data for B. koreanus will provide insights into rotifer biology and physiology and facilitate the development of biomarkers for ecotoxicology studies.

  13. Inheritance and diversification of symbiotic trichonymphid flagellates from a common ancestor of termites and the cockroach Cryptocercus.

    PubMed

    Ohkuma, Moriya; Noda, Satoko; Hongoh, Yuichi; Nalepa, Christine A; Inoue, Tetsushi

    2009-01-22

    Cryptocercus cockroaches and lower termites harbour obligate, diverse and unique symbiotic cellulolytic flagellates in their hindgut that are considered critical in the development of social behaviour in their hosts. However, there has been controversy concerning the origin of these symbiotic flagellates. Here, molecular sequences encoding small subunit rRNA and glyceraldehyde-3-phosphate dehydrogenase were identified in the symbiotic flagellates of the order Trichonymphida (phylum Parabasalia) in the gut of Cryptocercus punctulatus and compared phylogenetically to the corresponding species in termites. In each of the monophyletic lineages that represent family-level groups in Trichonymphida, the symbionts of Cryptocercus were robustly sister to those of termites. Together with the recent evidence for the sister-group relationship of the host insects, this first comprehensive study comparing symbiont molecular phylogeny strongly suggests that a set of symbiotic flagellates representative of extant diversity was already established in an ancestor common to Cryptocercus and termites, was vertically transmitted to their offspring, and subsequently became diversified to distinct levels, depending on both the host and the symbiont lineages.

  14. 'Candidatus Ancillula trichonymphae', a novel lineage of endosymbiotic Actinobacteria in termite gut flagellates of the genus Trichonympha.

    PubMed

    Strassert, Jürgen F H; Köhler, Tim; Wienemann, Tobias H G; Ikeda-Ohtsubo, Wakako; Faivre, Nicolas; Franckenberg, Sibylle; Plarre, Rudy; Radek, Renate; Brune, Andreas

    2012-12-01

    Termite gut flagellates are colonized by host-specific lineages of ectosymbiotic and endosymbiotic bacteria. Previous studies have shown that flagellates of the genus Trichonympha may harbour more than one type of symbiont. Using a comprehensive approach that combined cloning of SSU rRNA genes with fluorescence in situ hybridization and electron microscopy, we investigated the phylogeny and subcellular locations of the symbionts in a variety of Trichonympha species from different termites. The flagellates in Trichonympha Cluster I were the only species associated with 'Endomicrobia', which were located in the posterior part of the cell, confirming previous results. Trichonympha species of Cluster II from the termite genus Incisitermes (family Kalotermitidae) lacked 'Endomicrobia' and were associated with endosymbiotic Actinobacteria, which is highly unusual. The endosymbionts, for which we suggest the name 'Candidatus Ancillula trichonymphae', represent a novel, deep-branching lineage in the Micrococcineae that consists exclusively of clones from termite guts. They preferentially colonized the anterior part of the flagellate host and were highly abundant in all species of Trichonympha Cluster II except Trichonympha globulosa. Here, they were outnumbered by a Desulfovibrio species associated with the cytoplasmic lamellae at the anterior cell pole. Such symbionts are present in both Trichonympha clusters, but not in all species. Unlike the intracellular location reported for the Desulfovibrio symbionts of Trichonympha agilis (Cluster I), the Desulfovibrio symbionts of T. globulosa (Cluster II) were situated in deep invaginations of the plasma membrane that were clearly connected to the exterior of the host cell.

  15. Chemosensory response of marine flagellate towards L- and D- dissolved free amino acids generated during heavy grazing on bacteria.

    PubMed

    Ayo, Begoña; Txakartegi, Aitziber; Baña, Zuriñe; Artolozaga, Itxaso; Iriberri, Juan

    2010-09-01

    This study investigated the generation of dissolved free amino acids (DFAA) by the bacterivorous flagellate Rhynchomonas nasuta when feeding on abundant prey. Specifically, it examined whether this flagellate protist exhibits a chemosensory response towards those amino acids. The concentrations of glycine and the L- and D-enantiomers of glutamate, serine, threonine, alanine, and leucine were determined in co-cultures of the flagellate and bacteria. Glycine, L- and D-alanine, and L-serine were found to accumulate under these conditions in amounts that correlated positively with flagellate abundance, suggesting that protists are involved in their generation. Investigations of the chemotactic response of young and old foraging protists to the same amino acids, offered in concentrations similar to those previously generated, showed that glycine elicited the strongest attraction in both age groups. Young protists were strongly attracted to all the assayed amino acids, whereas older protists maintained a high level of attraction only for glycine. These results suggest that glycine generated by protists actively grazing in bacterially enriched patches functions as an infochemical, signaling to foraging protists the presence of available prey in the aquatic environment.

  16. The bacterivorous soil flagellate Heteromita globosa reduces bacterial clogging under denitrifying conditions in sand-filled aquifer columns.

    PubMed

    Mattison, Richard G; Taki, Hironori; Harayama, Shigeaki

    2002-09-01

    An exopolymer (slime)-producing soil bacterium Pseudomonas sp. (strain PS+) rapidly clogged sand-filled columns supplied with air-saturated artificial groundwater containing glucose (500 mg liter(-1)) as a sole carbon source and nitrate (300 mg liter(-1)) as an alternative electron acceptor. After 80 days of operation under denitrifying conditions, the effective porosity and saturated hydraulic conductivity (permeability) of sand in these columns had fallen by 2.5- and 26-fold, respectively. Bacterial biofilms appeared to induce clogging by occluding pore spaces with secreted exopolymer, although there may also have been a contribution from biogas generated during denitrification. The bacterivorous soil flagellate Heteromita globosa minimized reductions in effective porosity (1.6-fold) and permeability (13-fold), presumably due to grazing control of biofilms. Grazing may have limited growth of bacterial biomass and hence the rate of exopolymer and biogas secretion into pore spaces. Evidence for reduction in biogas production is suggested by increased nitrite efflux from columns containing flagellates, without a concomitant increase in nitrate consumption. There was no evidence that flagellates could improve flow conditions if added once clogging had occurred (60 days). Presumably, bacterial biofilms and their secretions were well established at that time. Nevertheless, this study provides evidence that bacterivorous flagellates may play a positive role in maintaining permeability in aquifers undergoing remediation treatments.

  17. Comparative transcriptome analysis of obligately asexual and cyclically sexual rotifers reveals genes with putative functions in sexual reproduction, dormancy, and asexual egg production

    PubMed Central

    2013-01-01

    Background Sexual reproduction is a widely studied biological process because it is critically important to the genetics, evolution, and ecology of eukaryotes. Despite decades of study on this topic, no comprehensive explanation has been accepted that explains the evolutionary forces underlying its prevalence and persistence in nature. Monogonont rotifers offer a useful system for experimental studies relating to the evolution of sexual reproduction due to their rapid reproductive rate and close relationship to the putatively ancient asexual bdelloid rotifers. However, little is known about the molecular underpinnings of sex in any rotifer species. Results We generated mRNA-seq libraries for obligate parthenogenetic (OP) and cyclical parthenogenetic (CP) strains of the monogonont rotifer, Brachionus calyciflorus, to identify genes specific to both modes of reproduction. Our differential expression analysis identified receptors with putative roles in signaling pathways responsible for the transition from asexual to sexual reproduction. Differential expression of a specific copy of the duplicated cell cycle regulatory gene CDC20 and specific copies of histone H2A suggest that such duplications may underlie the phenotypic plasticity required for reproductive mode switch in monogononts. We further identified differential expression of genes involved in the formation of resting eggs, a process linked exclusively to sex in this species. Finally, we identified transcripts from the bdelloid rotifer Adineta ricciae that have significant sequence similarity to genes with higher expression in CP strains of B. calyciflorus. Conclusions Our analysis of global gene expression differences between facultatively sexual and exclusively asexual populations of B. calyciflorus provides insights into the molecular nature of sexual reproduction in rotifers. Furthermore, our results offer insight into the evolution of obligate asexuality in bdelloid rotifers and provide indicators

  18. Vertical distribution of the chloromonad flagellate Heterosigma carterae in columns: Implications for bloom development

    USGS Publications Warehouse

    Hershberger, P.K.; Rensel, J.E.; Matter, A.L.; Taub, F.B.

    1998-01-01

    Blooms of the marine flagellate Heterosigma carterae have been associated with catastrophic fish kills at mariculture facilities around the world. The precise cause(s) of the sudden appearance and disappearance of Heterosigma surface blooms has not been completely described or understood. Environmental data from prior studies of blooms indicate the presence of vertical stratification of the water column that is often induced by freshwater runoff. We report the relatively rapid concentration of Heterosigma cells at the surface of tubes shortly after the addition of distilled water to the surface. This phenomenon of cell concentration in surface waters may partially explain the sudden appearance of Heterosigma cells near the surface and subsequent disappearance when vertical stratification is lost due to turbulence or mixing. The results may lead to bloom mitigation techniques for net pen aquaculture.

  19. Graviperception in the flagellate Euglena gracilis during a shuttle space flight.

    PubMed

    Häder, D P; Rosum, A; Schäfer, J; Hemmersbach, R

    1996-06-27

    During a recent space flight, gravitaxis of the unicellular photosynthetic flagellate, Euglena gracilis, was studied on board of the American shuttle Columbia. Accelerations were varied between 0 and 1.5 x g using a slow rotating centrifuge microscope (NIZEMI). The cells showed a sigmoidal response curve for the dependence of the precision of gravitaxis on acceleration which is indicative of the involvement of an active, physiological gravireceptor with a threshold at g-values < or = 0.16 x g and a saturation at g-values > or = 1 x g. No adaptation to microgravity was found during the prolonged space mission. After return the cells showed a normal gravitactic behavior at 1 x g. Since the cells are heavier than water, their swimming velocity is affected by sedimentation. The velocity distribution at different accelerations closely follows Stokes' law for sedimentation indicating that, in contrast to the ciliate Paramecium, E. gracilis, does not show any gravikinesis.

  20. Phototaxis in the flagellate, Euglena gracilis, under the effect of microgravity.

    PubMed

    Kuhnel-Kratz, C h; Schafer, J; Hader, D P

    1993-09-01

    Positive phototaxis was analyzed in the unicellular photosynthetic flagellate, Euglena gracilis, under the conditions of microgravity during a parabolic rocket flight (TEXUS experiment). The fluence rate at which positive phototaxis changes to negative phototaxis was the same in a sample which had previously been exposed to microgravity as in a sample which had not been exposed to microgravity. During weightlessness the precision of positive phototaxis is higher than at 1 g at the same fluence rate. The swimming velocity of the cells is higher at 0 g than at 1 g confirming previous results that under terrestrial conditions the cells are subject to simultaneous sedimentation while they swim upward. Tracks of organisms recorded at 0 g show much more frequent deviations from the straight path than those at 1 g.

  1. Phylogeny of the bodonid flagellates (Kinetoplastida) based on small-subunit rRNA gene sequences.

    PubMed

    Dolezel, D; Jirků, M; Maslov, D A; Lukes, J

    2000-09-01

    The phylogeny of kinetoplastid flagellates was investigated by determining the sequences of the small-subunit (18S) rRNA from Bodo designis, Bodo saltans K, Bodo saltans P, Bodo sorokini, Bodo sp. (cf. uncinatus), Cruzella marina, Cryptobia helicis, Dimastigella mimosa and Parabodo nitrophilus and analysing these data together with several previously obtained sequences. The root of the kinetoplastid tree was tentatively determined to be attached to the branch of B. designis and/or Cruzella marina. Within this topology, the suborder Trypanosomatina appears as a late-emerging monophyletic group, while the suborder Bodonina is paraphyletic. Within the bodonid subtree, the branches of parasitic organisms were intermingled with free-living ones, implying multiple transitions to parasitism. The tree indicates that the genera Cryptobia and Bodo are artificial taxa. In addition, the separation of the fish cryptobias and Trypanoplasma borreli as different genera was not supported.

  2. Miocene Coralline algae

    SciTech Connect

    Bosence, D.W.J.

    1988-01-01

    The coralline algae (Order Corallinales) were sedimentologically and ecologically important during the Miocene, a period when they were particularly abundant. The many poorly described and illustrated species and the lack of quantitative data in coralline thalli make specific determinations particularly difficult, but some species are well known and widespread in the Tethyan area. The sedimentologic importance of the Miocene coralline algae is reflected in the abundance of in-situ coralline buildups, rhodoliths, and coralline debris facies at Malta and Spain; similar sequences are known throughout the Tethyan Miocene. In-situ buildups vary from leafy crustose biostromes to walled reefs with dense coralline crusts and branches. Growth forms are apparently related to hydraulic energy. Rhodoliths vary from leafy, crustose, and open-branched forms in muddy sediments to dense, crustose, and radial-branching forms in coarse grainstones. Rhodolith form and internal structure correlate closely with hydraulic energy. Coralline genera are conservative and, as such, are useful in paleoenvironmental analysis. Of particular interest are the restricted depth ranges of recent coralline genera. More research is needed on the sedimentology, paleoecology, and systematics of the Cenozoic corallines, as they have particular value in paleoenvironmental analysis.

  3. Spatial and temporal escape from fungal parasitism in natural communities of anciently asexual bdelloid rotifers

    PubMed Central

    Wilson, Christopher G.; Sherman, Paul W.

    2013-01-01

    Sexual reproduction is costly, but it is nearly ubiquitous among plants and animals, whereas obligately asexual taxa are rare and almost always short-lived. The Red Queen hypothesis proposes that sex overcomes its costs by enabling organisms to keep pace with coevolving parasites and pathogens. If so, the few cases of stable long-term asexuality ought to be found in groups whose coevolutionary interactions with parasites are unusually weak. In theory, antagonistic coevolution will be attenuated if hosts disperse among patches within a metapopulation separately from parasites and more rapidly. We examined whether these conditions are met in natural communities of bdelloid rotifers, one of the longest-lived asexual lineages. At any life stage, these microscopic invertebrates can tolerate the complete desiccation of their ephemeral freshwater habitats, surviving as dormant propagules that are readily carried by the wind. In our field experiments, desiccation and wind transport enabled bdelloids to disperse independently of multiple fungal parasites, in both time and space. Surveys of bdelloid communities in unmanipulated moss patches confirmed that fungal parasitism was negatively correlated with extended drought and increasing height (exposure to wind). Bdelloid ecology therefore matches a key condition of models in which asexuals persist through spatio-temporal decoupling from coevolving enemies. PMID:23825214

  4. Spatial and temporal escape from fungal parasitism in natural communities of anciently asexual bdelloid rotifers.

    PubMed

    Wilson, Christopher G; Sherman, Paul W

    2013-08-22

    Sexual reproduction is costly, but it is nearly ubiquitous among plants and animals, whereas obligately asexual taxa are rare and almost always short-lived. The Red Queen hypothesis proposes that sex overcomes its costs by enabling organisms to keep pace with coevolving parasites and pathogens. If so, the few cases of stable long-term asexuality ought to be found in groups whose coevolutionary interactions with parasites are unusually weak. In theory, antagonistic coevolution will be attenuated if hosts disperse among patches within a metapopulation separately from parasites and more rapidly. We examined whether these conditions are met in natural communities of bdelloid rotifers, one of the longest-lived asexual lineages. At any life stage, these microscopic invertebrates can tolerate the complete desiccation of their ephemeral freshwater habitats, surviving as dormant propagules that are readily carried by the wind. In our field experiments, desiccation and wind transport enabled bdelloids to disperse independently of multiple fungal parasites, in both time and space. Surveys of bdelloid communities in unmanipulated moss patches confirmed that fungal parasitism was negatively correlated with extended drought and increasing height (exposure to wind). Bdelloid ecology therefore matches a key condition of models in which asexuals persist through spatio-temporal decoupling from coevolving enemies.

  5. The Rotifer fauna of Guatemala and Belize: survey and biogeographical affinities.

    PubMed

    García-Morales, Alma Estrella; Elías-Gutiérrez, Manuel

    2007-06-01

    Rotifer samples were obtained from 29 localities in northern Guatemala and central-southern Belize during March 2000 and June 2001. A total of 119 species were identified. Ten selected taxa are illustrated and commented: Euchlanis semicarinata, Lepadella apsicora, L. cryphaea, Lecane curvicornis f. lofuana, L. whitfordi, Monommata maculata, Scaridium bostjani, Trichocerca elongata f. braziliensis, and Z. hollaerti. The species Lepadella rhomboidula is a first record for the American Continent. The species are 71% cosmopolitan, 6 % tropicopolitan, and 4.2 % restricted to the subtropics. The Guatemala species number range was Petén-Itza lake (53 taxa), and Raxruja pool (three). La Democracia pool (49 taxa), and the Blue Hole sink-hole (six species) were the extremes in Belize. In total, 68 of the recorded taxa are new for Guatemala and 91 for Belize. Additionally, 47 species are registered by the first time in Central America. A comparison between these two countries and Mexico revealed that the south part of the latter conform a cluster with them, emphasizing the transitional character of this region between the Nearctics and the Neotropics. Furthermore, Guatemala and Belize have differences in species assemblages, as a response to the nature of their particular environments and topographical accidents. PMID:19069767

  6. The Rotifer fauna of Guatemala and Belize: survey and biogeographical affinities.

    PubMed

    García-Morales, Alma Estrella; Elías-Gutiérrez, Manuel

    2007-06-01

    Rotifer samples were obtained from 29 localities in northern Guatemala and central-southern Belize during March 2000 and June 2001. A total of 119 species were identified. Ten selected taxa are illustrated and commented: Euchlanis semicarinata, Lepadella apsicora, L. cryphaea, Lecane curvicornis f. lofuana, L. whitfordi, Monommata maculata, Scaridium bostjani, Trichocerca elongata f. braziliensis, and Z. hollaerti. The species Lepadella rhomboidula is a first record for the American Continent. The species are 71% cosmopolitan, 6 % tropicopolitan, and 4.2 % restricted to the subtropics. The Guatemala species number range was Petén-Itza lake (53 taxa), and Raxruja pool (three). La Democracia pool (49 taxa), and the Blue Hole sink-hole (six species) were the extremes in Belize. In total, 68 of the recorded taxa are new for Guatemala and 91 for Belize. Additionally, 47 species are registered by the first time in Central America. A comparison between these two countries and Mexico revealed that the south part of the latter conform a cluster with them, emphasizing the transitional character of this region between the Nearctics and the Neotropics. Furthermore, Guatemala and Belize have differences in species assemblages, as a response to the nature of their particular environments and topographical accidents.

  7. Complete mitochondrial genome of the monogonont rotifer, Brachionus koreanus (Rotifera, Brachionidae).

    PubMed

    Hwang, Dae-Sik; Suga, Koushirou; Sakakura, Yoshitaka; Park, Heum Gi; Hagiwara, Atsushi; Rhee, Jae-Sung; Lee, Jae-Seong

    2014-02-01

    The complete mitochondrial genome was obtained from the assembled genome data sequenced by next generation sequencing (NGS) technology from the monogonont rotifer Brachionus koreanus. The mitochondrial genome of B. koreanus was composed of two circular chromosomes designated as mtDNA-I (10,421 bp) and mtDNA-II (11,923 bp). The gene contents of B. koreanus were identical with previously reported B. plicatilis mitochondrial genomes. However, gene orders of B. koreanus showed one rearrangement between the two species. Of 12 protein-coding genes (PCGs), 3 genes (ATP6, ND1, and ND3) had an incomplete stop codon. The A + T base composition of B. koreanus mitochondrial genome was high (68.81%). They also showed anti-G bias (12.03% and 10.97%) on the second and third position of PCGs as well as slight anti-C bias (15.96% and 14.31%) on the first and third position of PCGs.

  8. Use of rotifers for the maintenance of monoalgal mass cultures of Spirulina

    SciTech Connect

    Mitchell, S.A.; Richmond, A.

    1987-01-01

    Zooplankton was successfully used for the biological control of unicellular algal contaminants in Spirulina mass cultures even under conditions adverse to the growth of Spirulina (maximal winter daily temperature of approximately 10 degrees C and very low bicarbonate concentration). Brachionus plicatilis (Rotifera) was the most successful species of zooplankton used. The interrelationships between Spirulina, green unicellular contaminant, and B. plicatilis were studied under various conditions. Two species of unicellular contaminant were used; Monoraphidium minutum was isolated from local cultures and Chlorella vulgaris, obtained from contaminated Spirulina cultures in Israel. The rotifer B. plicatilis successfully controlled the population size of both contaminants whether they were introduced in a single addition or as a daily dose. The biological control of the unicellular contaminants allows Spirulina to be cultured in a medium low in bicarbonate, thereby reducing the cost of the medium and increasing the quantity of CO2 that may be freely absorbed from the atmosphere at the optimal pH for Spirulina cultivation. (Refs. 9).

  9. Acute and chronic toxicity of six anticancer drugs on rotifers and crustaceans.

    PubMed

    Parrella, Alfredo; Lavorgna, Margherita; Criscuolo, Emma; Russo, Chiara; Fiumano, Vittorio; Isidori, Marina

    2014-11-01

    The growing use of cytostatic drugs is gaining relevance as an environmental concern. Environmental and distribution studies are increasing due to the development of accurate analytical methods, whereas ecotoxicological studies are still lacking. The aim of the present study was to investigate the acute and chronic toxicity of six cytostatics (5-fluorouracil, capecitabine, cisplatin, doxorubicin, etoposide, and imatinib) belonging to five classes of Anatomical Therapeutic Classification (ATC) on primary consumers of the aquatic chain (Daphnia magna, Ceriodaphnia dubia, Brachionus calyciflorus, and Thamnocephalus platyurus). Acute ecotoxicological effects occurred at concentrations in the order of mgL(-)(1), higher than those predicted in the environment, and the most acutely toxic drugs among those tested were cisplatin and doxorubicin for most aquatic organisms. For chronic toxicity, cisplatin and 5-fluorouracil showed the highest toxic potential in all test organisms, inducing 50% reproduction inhibition in crustaceans at concentrations on the order of μgL(-)(1). Rotifers were less susceptible to these pharmaceuticals. On the basis of chronic results, the low effective concentrations suggest a potential environmental risk of cytostatics. Thus, this study could be an important starting point for establishing the real environmental impact of these substances.

  10. Cellular Auxin Transport in Algae.

    PubMed

    Zhang, Suyun; van Duijn, Bert

    2014-01-01

    The phytohormone auxin is one of the main directors of plant growth and development. In higher plants, auxin is generated in apical plant parts and transported from cell-to-cell in a polar fashion. Auxin is present in all plant phyla, and the existence of polar auxin transport (PAT) is well established in land plants. Algae are a group of relatively simple, autotrophic, photosynthetic organisms that share many features with land plants. In particular, Charophyceae (a taxon of green algae) are closest ancestors of land plants. In the study of auxin function, transport and its evolution, the algae form an interesting research target. Recently, proof for polar auxin transport in Chara species was published and auxin related research in algae gained more attention. In this review we discuss auxin transport in algae with respect to land plants and suggest directions for future studies. PMID:27135491

  11. Cellular Auxin Transport in Algae.

    PubMed

    Zhang, Suyun; van Duijn, Bert

    2014-01-27

    The phytohormone auxin is one of the main directors of plant growth and development. In higher plants, auxin is generated in apical plant parts and transported from cell-to-cell in a polar fashion. Auxin is present in all plant phyla, and the existence of polar auxin transport (PAT) is well established in land plants. Algae are a group of relatively simple, autotrophic, photosynthetic organisms that share many features with land plants. In particular, Charophyceae (a taxon of green algae) are closest ancestors of land plants. In the study of auxin function, transport and its evolution, the algae form an interesting research target. Recently, proof for polar auxin transport in Chara species was published and auxin related research in algae gained more attention. In this review we discuss auxin transport in algae with respect to land plants and suggest directions for future studies.

  12. Ecology of Harmful Algae

    NASA Astrophysics Data System (ADS)

    Roelke, Daniel L.

    2007-07-01

    Edna Graneli and Jefferson T. Turner, Editors;Ecological Studies Series, Vol. 189; Springer; ISBN 3540322094; 413 pp.; 2006; $195 Harmful algal blooms (HABs) affect commercially and recreationally important species, human health, and ecosystem functioning. Hallmark events are the visually stunning blooms where waters are discolored and filled with ichthyotoxin-producing algae that lead to large fish kills. Of most concern, however, are HABs that pose a threat to human health. For example, some phycotoxins bioaccumulate in the guts and tissues of commercially and recreationally important species that when consumed by humans, may result in nausea, paralysis, memory loss, and even death. In addition to the deleterious impacts of phycotoxins, HABs can be problematic in other ways. For example, the decay of blooms often leads to low dissolved oxygen in subsurface waters. Blooms also reduce light penetration into the water column. Both processes disrupt ecosystems and in some cases have completely destroyed benthic communities.

  13. Fuel From Algae: Scaling and Commercialization of Algae Harvesting Technologies

    SciTech Connect

    2010-01-15

    Broad Funding Opportunity Announcement Project: Led by CEO Ross Youngs, AVS has patented a cost-effective dewatering technology that separates micro-solids (algae) from water. Separating micro-solids from water traditionally requires a centrifuge, which uses significant energy to spin the water mass and force materials of different densities to separate from one another. In a comparative analysis, dewatering 1 ton of algae in a centrifuge costs around $3,400. AVS’s Solid-Liquid Separation (SLS) system is less energy-intensive and less expensive, costing $1.92 to process 1 ton of algae. The SLS technology uses capillary dewatering with filter media to gently facilitate water separation, leaving behind dewatered algae which can then be used as a source for biofuels and bio-products. The biomimicry of the SLS technology emulates the way plants absorb and spread water to their capillaries.

  14. [From algae to "functional foods"].

    PubMed

    Vadalà, M; Palmieri, B

    2015-01-01

    In the recent years, a growing interest for nutraceutical algae (tablets, capsules, drops) has been developed, due to their effective health benefits, as a potential alternative to the classic drugs. This review explores the use of cyanobacterium Spirulina, the microalgae Chlorella, Dunaliella, Haematococcus, and the macroalgae Klamath, Ascophyllum, Lithothamnion, Chondrus, Hundaria, Glacilaria, Laminaria, Asparagopsis, Eisenia, Sargassum as nutraceuticals and dietary supplements, in terms of production, nutritional components and evidence-based health benefits. Thus, our specific goals are: 1) Overview of the algae species currently used in nutraceuticals; 2) Description of their characteristics, action mechanisms, and possible side effects; 3) Perspective of specific algae clinical investigations development. PMID:26378764

  15. Temperature-dependent toxicities of four common chemical pollutants to the marine medaka fish, copepod and rotifer.

    PubMed

    Li, Adela J; Leung, Priscilla T Y; Bao, Vivien W W; Yi, Andy X L; Leung, Kenneth M Y

    2014-10-01

    We hypothesize that chemical toxicity to marine ectotherms is the lowest at an optimum temperature (OT) and it exacerbates with increasing or decreasing temperature from the OT. This study aimed to verify this hypothetical temperature-dependent chemical toxicity (TDCT) model through laboratory experiments. Acute toxicity over a range of temperatures was tested on four commonly used chemicals to three marine ectotherms. Our results confirmed that toxicities, in terms of 96-h LC50 (median lethal concentration; for the marine medaka fish Oryzias melastigma and the copepod Tigriopus japonicus) and 24-h LC50 (for the rotifer Brachionus koreanus), were highly temperature-dependent, and varied between test species and between study chemicals. The LC50 value of the fish peaked at 20 °C for copper (II) sulphate pentahydrate and triphenyltin chloride, and at 25 °C for dichlorophenyltrichloroethane and copper pyrithione, and decreased with temperature increase or decrease from the peak (i.e., OT). However, LC50 values of the copepod and the rotifer generally showed a negative relationship with temperature across all test chemicals. Both copepod and rotifer entered dormancy at the lowest temperature of 4 °C. Such metabolic depression responses in these zooplanktons could reduce their uptake of the chemical and hence minimize the chemical toxicity at low temperatures. Our TDCT model is supported by the fish data only, whereas a simple linear model fits better to the zooplankton data. Such species-specific TDCT patterns may be jointly ascribed to temperature-mediated changes in (1) the physiological response and susceptibility of the marine ectotherms to the chemical, (2) speciation and bioavailability of the chemical, and (3) toxicokinetics of the chemical in the organisms.

  16. Temperature-dependent toxicities of four common chemical pollutants to the marine medaka fish, copepod and rotifer.

    PubMed

    Li, Adela J; Leung, Priscilla T Y; Bao, Vivien W W; Yi, Andy X L; Leung, Kenneth M Y

    2014-10-01

    We hypothesize that chemical toxicity to marine ectotherms is the lowest at an optimum temperature (OT) and it exacerbates with increasing or decreasing temperature from the OT. This study aimed to verify this hypothetical temperature-dependent chemical toxicity (TDCT) model through laboratory experiments. Acute toxicity over a range of temperatures was tested on four commonly used chemicals to three marine ectotherms. Our results confirmed that toxicities, in terms of 96-h LC50 (median lethal concentration; for the marine medaka fish Oryzias melastigma and the copepod Tigriopus japonicus) and 24-h LC50 (for the rotifer Brachionus koreanus), were highly temperature-dependent, and varied between test species and between study chemicals. The LC50 value of the fish peaked at 20 °C for copper (II) sulphate pentahydrate and triphenyltin chloride, and at 25 °C for dichlorophenyltrichloroethane and copper pyrithione, and decreased with temperature increase or decrease from the peak (i.e., OT). However, LC50 values of the copepod and the rotifer generally showed a negative relationship with temperature across all test chemicals. Both copepod and rotifer entered dormancy at the lowest temperature of 4 °C. Such metabolic depression responses in these zooplanktons could reduce their uptake of the chemical and hence minimize the chemical toxicity at low temperatures. Our TDCT model is supported by the fish data only, whereas a simple linear model fits better to the zooplankton data. Such species-specific TDCT patterns may be jointly ascribed to temperature-mediated changes in (1) the physiological response and susceptibility of the marine ectotherms to the chemical, (2) speciation and bioavailability of the chemical, and (3) toxicokinetics of the chemical in the organisms. PMID:25098775

  17. Transgenic algae engineered for higher performance

    SciTech Connect

    Unkefer, Pat J; Anderson, Penelope S; Knight, Thomas J

    2014-10-21

    The present disclosure relates to transgenic algae having increased growth characteristics, and methods of increasing growth characteristics of algae. In particular, the disclosure relates to transgenic algae comprising a glutamine phenylpyruvate transaminase transgene and to transgenic algae comprising a glutamine phenylpyruvate transaminase transgene and a glutamine synthetase.

  18. Light-dependent transcriptional events during resting egg hatching of the rotifer Brachionus manjavacas.

    PubMed

    Kim, Hee-Jin; Suga, Koushirou; Kim, Bo-Mi; Rhee, Jae-Sung; Lee, Jae-Seong; Hagiwara, Atsushi

    2015-04-01

    Rotifer resting eggs often have to endure harsh environmental conditions during the diapause phase. They are stimulated by light to hatch. In order to study the hatching mechanism, we observed resting eggs and measured their transcriptional expression under different light exposure periods (total darkness, and after 30 min, and 4h light). By using differential-display reverse transcription PCR (DDRT-PCR), we isolated 80 genes that displayed different expression patterns in response to the three light treatments: 20 genes were expressed in total darkness, 40 different genes were differentially expressed under 30 min light, and 20 further genes were expressed after 4h of light. The resting eggs showed no phenotypic differences in embryonic development during the 4h illumination period. In general, the expression patterns of the analyzed genes in resting eggs were differentially modulated by light exposure time. In total darkness, resting eggs mainly expressed genes encoding cell defense and homeostasis functions. In the 30 min illumination group, we found enriched expression of genes encoding fatty acid metabolism-related components, including Acyl-CoA dehydrogenase (ACAD). Genes encoding cellular and embryonic developmental functions were highly observed in the 30 min-illuminated group but were not observed in the 4h-illuminated group. Real-time RT-PCR revealed that several transcripts such as encoding V-type H(+)-translocating pyrophosphatase (V-PPase) and Meckelin had prolonged expression levels when exposed to light for 4h. In the 4h illuminated group, the RecQ protein-like 5 (RECQL5) gene was enriched. This RECQL5 gene may be expressed to protect the developing embryo from continuous light exposure. The data presented in this study indicate that DDRT-PCR-aided gene screening can be helpful to isolate candidate genes involved in the hatching process.

  19. Lethal and sublethal effects of selected PPCPs on the freshwater rotifer, Plationus patulus.

    PubMed

    Martinez Gomez, Diana A; Baca, Sarah; Walsh, Elizabeth J

    2015-04-01

    Pharmaceuticals and personal care products (PPCPs) have been reported in surface waters around the world. The continuous input of these pollutants into freshwaters and their potential effects on aquatic life are of increasing concern. The rotifer Plationus patulus, a basal member of riverine food webs, was used to test acute and chronic toxicity of 4 PPCPs (acetamidophenol, caffeine, fluoxetine, triclosan). A population from a remote site in Mexico (reference population) and one from an urbanized stretch of the Rio Grande were exposed. Acute toxicity tests show that both populations were more sensitive to fluoxetine. Chronic exposure to acetamidophenol (10 mg/L, 15 mg/L, and 20 mg/L) inhibited reference population growth, whereas Rio Grande population growth was inhibited only at 15 mg/L and 20 mg/L. Population growth was inhibited at 200 mg/L and 300 mg/L of caffeine for both populations. Chronic exposure to fluoxetine (0.020 mg/L) significantly inhibited population growth for the Rio Grande population only. Triclosan (0.05 mg/L, 0.075 mg/L, 0.10 mg/L) had the most deleterious effects, significantly reducing both populations' growth rates. Sublethal effects of chronic exposure to PPCPs included decreased egg production and increased egg detachment. A mixed exposure (6 PPCPs, environmentally relevant concentrations) did not affect population growth in either population. However, the continuous introduction of a broad suite of PPCPs to aquatic ecosystems still may present a risk to aquatic communities. Environ Toxicol Chem 2015;34:913-922. © 2014 SETAC. PMID:25557148

  20. Lethal and sublethal effects of selected PPCPs on the freshwater rotifer, Plationus patulus.

    PubMed

    Martinez Gomez, Diana A; Baca, Sarah; Walsh, Elizabeth J

    2015-04-01

    Pharmaceuticals and personal care products (PPCPs) have been reported in surface waters around the world. The continuous input of these pollutants into freshwaters and their potential effects on aquatic life are of increasing concern. The rotifer Plationus patulus, a basal member of riverine food webs, was used to test acute and chronic toxicity of 4 PPCPs (acetamidophenol, caffeine, fluoxetine, triclosan). A population from a remote site in Mexico (reference population) and one from an urbanized stretch of the Rio Grande were exposed. Acute toxicity tests show that both populations were more sensitive to fluoxetine. Chronic exposure to acetamidophenol (10 mg/L, 15 mg/L, and 20 mg/L) inhibited reference population growth, whereas Rio Grande population growth was inhibited only at 15 mg/L and 20 mg/L. Population growth was inhibited at 200 mg/L and 300 mg/L of caffeine for both populations. Chronic exposure to fluoxetine (0.020 mg/L) significantly inhibited population growth for the Rio Grande population only. Triclosan (0.05 mg/L, 0.075 mg/L, 0.10 mg/L) had the most deleterious effects, significantly reducing both populations' growth rates. Sublethal effects of chronic exposure to PPCPs included decreased egg production and increased egg detachment. A mixed exposure (6 PPCPs, environmentally relevant concentrations) did not affect population growth in either population. However, the continuous introduction of a broad suite of PPCPs to aquatic ecosystems still may present a risk to aquatic communities. Environ Toxicol Chem 2015;34:913-922. © 2014 SETAC.

  1. Algae fuel clean electricity generation

    SciTech Connect

    O'Sullivan, D.

    1993-02-08

    The paper describes plans for a 600-kW pilot generating unit, fueled by diesel and Chlorella, a green alga commonly seen growing on the surface of ponds. The plant contains Biocoil units in which Chlorella are grown using the liquid effluents from sewage treatment plants and dissolved carbon dioxide from exhaust gases from the combustion unit. The algae are partially dried and fed into the combustor where diesel fuel is used to maintain ignition. Diesel fuel is also used for start-up and as a backup fuel for seasonal shifts that affect the algae growing conditions. Since the algae use the carbon dioxide emitted during the combustion process, the process will not contribute to global warming.

  2. Composition of heterotrophic flagellates in coastal waters of different trophic status.

    PubMed

    Cheung, Man Kit; Nong, Wenyan; Kwan, Hoi Shan; Wong, Chong Kim

    2013-09-01

    Heterotrophic flagellates (HFs) are important members of the aquatic microbial food web. However, information on their spatial patterns in relation to eutrophication is limited. Here, we examined the composition and spatial distributions of HFs (<3 μm) in subtropical coastal waters of different trophic status by re-analyzing two previously published small subunit rDNA pyrosequence datasets using information from the newly launched Protist Ribosomal Reference database (PR(2)). Whereas the contributions of different major clades composing the Marine Stramenopiles (MASTs), picobiliphytes and Chrysophyceae were found relatively comparable between the stations, contrasting compositions of the Marine Alveolates (MALV) groups I and II were observed. The high and relatively stable contribution of MAST-1, -3 and -7 among the MASTs in both stations suggest their importance as bacterial grazers in coastal waters, irrespective of trophic status. By contrast, the dominance of clades 3, 5 and 14 of MALV II in the eutrophic station implies their importance in regulating the dinoflagellate population at the site. Our study provides insights into the ecological importance of different HF groups in eutrophic coastal ecosystems. PMID:23636495

  3. Experimental infection of chickens by a flagellated motile strain of Salmonella enterica serovar Gallinarum biovar Gallinarum.

    PubMed

    Lopes, P D; Freitas Neto, O C; Batista, D F A; Denadai, J; Alarcon, M F F; Almeida, A M; Vasconcelos, R O; Setta, A; Barrow, P A; Berchieri, A

    2016-08-01

    Salmonella enterica subsp. enterica serovar Gallinarum biovar Gallinarum (SG) causes fowl typhoid (FT), a septicaemic disease which can result in high mortality in poultry flocks. The absence of flagella in SG is thought to favour systemic invasion, since bacterial recognition via Toll-like receptor (TLR)-5 does not take place during the early stages of FT. In the present study, chicks susceptible to FT were inoculated with a wild type SG (SG) or its flagellated motile derivative (SG Fla(+)). In experiment 1, mortality and clinical signs were assessed, whereas in experiment 2, gross pathology, histopathology, systemic invasion and immune responses were evaluated. SG Fla(+) infection resulted in later development of clinical signs, lower mortality, lower bacterial numbers in the liver and spleen, and less severe pathological changes compared to SG. The CD8(+) T lymphocyte population was higher in the livers of chicks infected with SG at 4 days post-inoculation (dpi). Chicks infected with SG had increased expression of interleukin (IL)-6 mRNA in the caecal tonsil at 1 dpi and increased expression of IL-18 mRNA in the spleen at 4 dpi. In contrast, the CD4(+) T lymphocyte population was higher at 6 dpi in the livers of birds infected with SG Fla(+). Therefore, flagella appeared to modulate the chicken immune response towards a CD4(+) T profile, resulting in more efficient bacterial clearance from systemic sites and milder infection. PMID:27387725

  4. Simulation of the flow field and tumbling dynamics of multiply flagellated bacterium

    NASA Astrophysics Data System (ADS)

    Larson, Ronald; Watari, Nobuhiko

    2009-11-01

    To study the hydrodynamics of swimming of multi-flagellated bacteria, such as Escherichia coli, we develop a simulation method using a bead-spring model to account for the hydrodynamic and the mechanical interactions between multiple flagella and the cell body, the reversal of the rotation of a flagellum in a tumble and associated polymorphic transformations of the flagellum. This simulation reproduces the experimentally observed behaviors of E. coli, namely, a three-dimensional random-walk trajectory in run-and-tumble motion and steady clockwise swimming near a wall. Here we show using a modeled cell that the polymorphic transformation of flagellum in a tumble facilitates the reorientation of the cell, and that the time-averaged flow field near a cell in a run has double-layered helical streamlines. Moreover, the instantaneous flow field, which is strongly time-dependent, is more than 10-fold larger in magnitude than the time-averaged flow, large enough to affect the migration behavior of surrounding chemoattractants, with the Peclet number for these molecules being larger than one near a swimming cell.

  5. Hydrodynamic effects on the tumbling of flagellated bacteria near a solid surface

    NASA Astrophysics Data System (ADS)

    Molaei, Mehdi; Sheng, Jian

    2011-11-01

    Peritrichously flagellated bacteria use semi-rigid helical flagella to form a bundle during a run to swim forward and to trigger the unbundling during a tumble to change their swimming direction. It is accepted that the hydrodynamic interactions play a significant role in these processes. Recently, using digital holographic microscopy and microfluidics, we discovered that the tumbling events are substantially suppressed near a solid wall. In this paper, we present a two flagellum rigid model to elucidate the hydrodynamic wall interaction mechanism behind the phenomenon. Further implications on cell attachment and detachment during the biofilm formation will be discussed. We apply Slender Body Theory (SBT) to quantify the flow flagellum interaction. The no-slip boundary imposed by the wall is modeled using the image system of the SBT model for the stoke-flow singularity. We show that in the bulk, a repulsive force among flagella initiates the unbundling and consequently tumbling; however, in presence of the wall, the force is strongly mitigated that stabilize the bundle and suppress the tumbling. NIH and NSF.

  6. Lineage-specific activities of a multipotent mitochondrion of trypanosomatid flagellates.

    PubMed

    Škodová-Sveráková, Ingrid; Verner, Zdeněk; Skalický, Tomáš; Votýpka, Jan; Horváth, Anton; Lukeš, Julius

    2015-04-01

    Trypanosomatids are a very diverse group composed of monoxenous and dixenous parasites belonging to the excavate class Kinetoplastea. Here we studied the respiration of five monoxenous species (Blechomonas ayalai, Herpetomonas muscarum, H. samuelpessoai, Leptomonas pyrrhocoris and Sergeia podlipaevi) introduced into culture, each representing a novel yet globally distributed and/or species-rich clade, and compare them with well-studied flagellates Trypanosoma brucei, Phytomonas serpens, Crithidia fasciculata and Leishmania tarentolae. Differences in structure and activities of respiratory chain complexes, respiration and other biochemical parameters recorded under laboratory conditions reveal their substantial diversity, likely a reflection of different host environments. Phylogenetic relationships of the analysed trypanosomatids do not correlate with their biochemical parameters, with the differences within clades by far exceeding those among clades. As the S. podlipaevi canonical respiratory chain complexes have very low activities, we believe that its mitochondrion is utilised for purposes other than oxidative phosphorylation. Hence, the single reticulated mitochondrion of diverse trypanosomatids seems to retain multipotency, with the capacity to activate its individual components based on the host environment.

  7. Physiological parameters of gravitaxis in the flagellate Euglena gracilis obtained during a parabolic flight campaign.

    PubMed

    Richter, Peter R; Schuster, Martin; Wagner, Helmut; Lebert, Michael; Hader, Donat-P

    2002-02-01

    The unicellular freshwater flagellate Euglena gracilis and its close relative Astasia longa show a pronounced negative gravitaxis. Previous experiments revealed that gravitaxis is most likely mediated by an active physiological mechanism in which changes of the internal calcium concentration and the membrane potential play an important role. In a recent parabolic flight experiment on board an aircraft (ESA 29th parabolic flight campaign), changes of graviorientation, membrane potential and the cytosolic calcium concentration upon changes of the acceleration (between 1 x g(n), 1.8 x g(n), microgravity) were monitored by image analysis and photometric methods using Oxonol VI (membrane potential) and Calcium Crimson (cytosolic calcium concentration). The parabolic flight maneuvers performed by the aircraft resulted in transient phases of 1.8 x g(n) (about 20 s), microgravity (about 22 s) followed by 1.8 x g(n) (about 20 s). A transient increase in the intracellular calcium concentration was detected from lower to higher accelerations (1 x g(n) to 1.8 x g(n) or microgravity to 1.8 x g(n)). Oxonol VI-labeled cells showed a signal, which indicates a depolarization during the transition from 1 x g(n) to 1.8 x g(n), a weak repolarization in microgravity followed by a rapid repolarization in the subsequent 1 x g(n) phase. The results show good coincidence with observations of recent terrestrial and space experiments.

  8. Transient Superdiffusion and Long-Range Correlations in the Motility Patterns of Trypanosomatid Flagellate Protozoa.

    PubMed

    Alves, Luiz G A; Scariot, Débora B; Guimarães, Renato R; Nakamura, Celso V; Mendes, Renio S; Ribeiro, Haroldo V

    2016-01-01

    We report on a diffusive analysis of the motion of flagellate protozoa species. These parasites are the etiological agents of neglected tropical diseases: leishmaniasis caused by Leishmania amazonensis and Leishmania braziliensis, African sleeping sickness caused by Trypanosoma brucei, and Chagas disease caused by Trypanosoma cruzi. By tracking the positions of these parasites and evaluating the variance related to the radial positions, we find that their motions are characterized by a short-time transient superdiffusive behavior. Also, the probability distributions of the radial positions are self-similar and can be approximated by a stretched Gaussian distribution. We further investigate the probability distributions of the radial velocities of individual trajectories. Among several candidates, we find that the generalized gamma distribution shows a good agreement with these distributions. The velocity time series have long-range correlations, displaying a strong persistent behavior (Hurst exponents close to one). The prevalence of "universal" patterns across all analyzed species indicates that similar mechanisms may be ruling the motion of these parasites, despite their differences in morphological traits. In addition, further analysis of these patterns could become a useful tool for investigating the activity of new candidate drugs against these and others neglected tropical diseases.

  9. [Mitosis in the free-living flagellate Bodo saltans strain PS+ (Kinetoplastidea, Bodonida)].

    PubMed

    Malysheva, M N; Karpova, M S; Frolov, A O

    2007-01-01

    The mitosis in the free-living flagellate Bodo saltans Ps+ with prokaryotic cytobionts in perinuclear space has been studied. The nuclear division in B. saltans Ps+ occurs by closed mitosis type without condensation of chromosomes. Two spatially separated mitotic spindles begin to form consistently at the initial stages of nuclear division. The spindle including about 20 microtubules appears first and later the second spindle with half the number of microtubules comes at the angle of 30-40 degrees. Both spindles rest their ends against the inner nuclear membrane and form 4 distinct poles. The microtubules of the first spindle are associated with 4 pairs of kinetochores, the microtubules of the second one are associated with 2 pairs of kinetochores. The divergence of the kinetochores towards the poles occurs independently in each spindle. The equatorial phase is not revealed in B. saltans Ps+. The poles of both spindles unite in pairs at the elongation phase of mitosis and form the integrated bipolar structure. At this stage of the nuclear division, the kinetochores reach the poles of subspindles and become indistinguishable. Then the nucleus takes the shape of a dumbbell. The inner nuclear membranes of just formed nuclei have layers of condensed chromatin characteristic of the interphase nuclei of kinetoplastidea. The daughter nuclei separate at the phase of reorganization. There are 1-2 prokaryotic endocytobionts in the perinuclear space of the interphase nuclei in B. saltans Ps+. The symbionts multiply during mitosis and their number reaches more than 20 specimens par nucleus.

  10. Morphological and molecular identification of Tetratrichomonas flagellates from the giant anteater (Myrmecophaga tridactyla).

    PubMed

    Ibañez-Escribano, A; Nogal-Ruiz, J J; Delclaux, M; Martinez-Nevado, E; Ponce-Gordo, F

    2013-08-01

    A tetratrichomonad flagellate found in the diarrhoeic faeces of a 5 years-old male giant anteater (Myrmecophaga tridactyla) was characterised by morphological and genetic analysis. This protozoan presents four anterior flagella of unequal length and a recurrent flagellum attached to the undulating membrane without a free end portion, and a broad axostyle projection. Numerous vacuoles of different sizes containing bacteria and digestion products were found. The complete sequence of the DNA coding for the 16S rRNA-ITS1-5.8S rRNA-ITS2 region was also obtained in order to compare this isolate with other tetratrichomonad species. The sequence obtained was identical to others previously obtained by other researchers from bovines and turtles (Geochelone sp.). It is not easily explainable how the same organism could be found in such different hosts and locations; however these results indicate that some tetratrichomonad species could have a wide host range and could survive in a wide range of environmental conditions.

  11. Transient Superdiffusion and Long-Range Correlations in the Motility Patterns of Trypanosomatid Flagellate Protozoa

    PubMed Central

    Alves, Luiz G. A.; Scariot, Débora B.; Guimarães, Renato R.; Nakamura, Celso V.; Mendes, Renio S.; Ribeiro, Haroldo V.

    2016-01-01

    We report on a diffusive analysis of the motion of flagellate protozoa species. These parasites are the etiological agents of neglected tropical diseases: leishmaniasis caused by Leishmania amazonensis and Leishmania braziliensis, African sleeping sickness caused by Trypanosoma brucei, and Chagas disease caused by Trypanosoma cruzi. By tracking the positions of these parasites and evaluating the variance related to the radial positions, we find that their motions are characterized by a short-time transient superdiffusive behavior. Also, the probability distributions of the radial positions are self-similar and can be approximated by a stretched Gaussian distribution. We further investigate the probability distributions of the radial velocities of individual trajectories. Among several candidates, we find that the generalized gamma distribution shows a good agreement with these distributions. The velocity time series have long-range correlations, displaying a strong persistent behavior (Hurst exponents close to one). The prevalence of “universal” patterns across all analyzed species indicates that similar mechanisms may be ruling the motion of these parasites, despite their differences in morphological traits. In addition, further analysis of these patterns could become a useful tool for investigating the activity of new candidate drugs against these and others neglected tropical diseases. PMID:27007779

  12. Effects of non-steroidal anti-inflammatory drugs on cyanobacteria and algae in laboratory strains and in natural algal assemblages.

    PubMed

    Bácsi, István; B-Béres, Viktória; Kókai, Zsuzsanna; Gonda, Sándor; Novák, Zoltán; Nagy, Sándor Alex; Vasas, Gábor

    2016-05-01

    In recent years measurable concentrations of non-steroidal anti-inflammatory drugs (NSAIDs) have been shown in the aquatic environment as a result of increasing human consumption. Effects of five frequently used non-steroidal anti-inflammatory drugs (diclofenac, diflunisal, ibuprofen, mefenamic acid and piroxicam in 0.1 mg ml(-1) concentration) in batch cultures of cyanobacteria (Synechococcus elongatus, Microcystis aeruginosa, Cylindrospermopsis raciborskii), and eukaryotic algae (Desmodesmus communis, Haematococcus pluvialis, Cryptomonas ovata) were studied. Furthermore, the effects of the same concentrations of NSAIDs were investigated in natural algal assemblages in microcosms. According to the changes of chlorophyll-a content, unicellular cyanobacteria seemed to be more tolerant to NSAIDs than eukaryotic algae in laboratory experiments. Growth of eukaryotic algae was reduced by all drugs, the cryptomonad C. ovata was the most sensitive to NSAIDs, while the flagellated green alga H. pluvialis was more sensitive than the non-motile green alga D. communis. NSAID treatments had weaker impact in the natural assemblages dominated by cyanobacteria than in the ones dominated by eukaryotic algae, confirming the results of laboratory experiments. Diversity and number of functional groups did not change notably in cyanobacteria dominated assemblages, while they decreased significantly in eukaryotic algae dominated ones compared to controls. The results highlight that cyanobacteria (especially unicellular ones) are less sensitive to the studied, mostly hardly degradable NSAIDs, which suggest that their accumulation in water bodies may contribute to the expansion of cyanobacterial mass productions in appropriate environmental circumstances by pushing back eukaryotic algae. Thus, these contaminants require special attention during wastewater treatment and monitoring of surface waters.

  13. Chronic toxicity of a laundry detergent to the freshwater flagellate Euglena gracilis.

    PubMed

    Azizullah, Azizullah; Richter, Peter; Jamil, Muhammad; Häder, Donat-Peter

    2012-10-01

    Chronic toxicity of the common laundry detergent Ariel on the freshwater alga Euglena gracilis was investigated by growing the alga in a medium containing the detergent for 7 days. Cell density, motility, swimming velocity, gravitactic orientation, cell shape, photosynthesis and concentration of light-harvesting pigments were used as end point parameters for the assessment of toxicity. Cell density was significantly reduced at a concentration of 1 mg l(-1) or above. Among the other tested parameters, with the exception of cell shape, gravitaxis and chlorophyll b, all were adversely affected by the detergent at concentrations exceeding 1 mg l(-1). It is concluded that long-term (7-days) exposure to the detergent caused significant toxicity to E. gracilis. Furthermore, long-term tests with E. gracilis can be used as sensitive indicator for the toxicity assessment of laundry detergents in aquatic environments.

  14. Combined effects of Corexit EC 9500A with secondary abiotic and biotic factors in the rotifer Brachionus plicatilis.

    PubMed

    Williams, Michael B; Powell, Mickie L; Watts, Stephen A

    2016-10-01

    We examined lethality and behavioral effects of Corexit EC 9500A (C-9500A) exposure on the model marine zooplankton Brachionus plicatilis singularly and in combination with abiotic and biotic factors. C-9500A exposure at standard husbandry conditions (17.5ppt, 24°C, 200 rotifer*mL(-1) density) identified the 24h median lethal concentration, by Probit analysis, to be 107ppm for cultured B. plicatilis. Rotifers surviving exposure to higher concentrations (100 and 150ppm) exhibited a decreased swimming velocity and a reduced net to gross movement ratio. Significant interaction between C-9500A exposure and temperature or salinity was observed. Upper thermal range was reduced and maximal salinity stress was seen as ca. 25ppt. Increased or decreased nutritional availability over the exposure period did not significantly alter mortality of B. plicatilis populations at the concentrations tested. Results from this study may be useful for predicting possible outcomes on marine zooplankton following dispersant application under diverse natural conditions. PMID:27327395

  15. Evidence Supporting the Uptake and Genomic Incorporation of Environmental DNA in the "Ancient Asexual" Bdelloid Rotifer Philodina roseola.

    PubMed

    Bininda-Emonds, Olaf R P; Hinz, Claus; Ahlrichs, Wilko H

    2016-01-01

    Increasing evidence suggests that bdelloid rotifers regularly undergo horizontal gene transfer, apparently as a surrogate mechanism of genetic exchange in the absence of true sexual reproduction, in part because of their ability to withstand desiccation. We provide empirical support for this latter hypothesis using the bdelloid Philodina roseola, which we demonstrate to readily internalize environmental DNA in contrast to a representative monogonont rotifer (Brachionus rubens), which, like other monogononts, is facultative sexual and cannot withstand desiccation. In addition, environmental DNA that was more similar to the host DNA was retained more often and for a longer period of time. Indirect evidence (increased variance in the reproductive output of the untreated F1 generation) suggests that environmental DNA can be incorporated into the genome during desiccation and is thus heritable. Our observed fitness effects agree with sexual theory and also occurred when the animals were desiccated in groups (thereby acting as DNA donors), but not individually, indicating the mechanism could occur in nature. Thus, although DNA uptake and its genomic incorporation appears proximally related to anhydrobiosis in bdelloids, it might also facilitate accidental genetic exchange with closely related taxa, thereby maintaining higher levels of genetic diversity than is otherwise expected for this group of "ancient asexuals". PMID:27608044

  16. Evidence Supporting the Uptake and Genomic Incorporation of Environmental DNA in the “Ancient Asexual” Bdelloid Rotifer Philodina roseola

    PubMed Central

    Bininda-Emonds, Olaf R. P.; Hinz, Claus; Ahlrichs, Wilko H.

    2016-01-01

    Increasing evidence suggests that bdelloid rotifers regularly undergo horizontal gene transfer, apparently as a surrogate mechanism of genetic exchange in the absence of true sexual reproduction, in part because of their ability to withstand desiccation. We provide empirical support for this latter hypothesis using the bdelloid Philodina roseola, which we demonstrate to readily internalize environmental DNA in contrast to a representative monogonont rotifer (Brachionus rubens), which, like other monogononts, is facultative sexual and cannot withstand desiccation. In addition, environmental DNA that was more similar to the host DNA was retained more often and for a longer period of time. Indirect evidence (increased variance in the reproductive output of the untreated F1 generation) suggests that environmental DNA can be incorporated into the genome during desiccation and is thus heritable. Our observed fitness effects agree with sexual theory and also occurred when the animals were desiccated in groups (thereby acting as DNA donors), but not individually, indicating the mechanism could occur in nature. Thus, although DNA uptake and its genomic incorporation appears proximally related to anhydrobiosis in bdelloids, it might also facilitate accidental genetic exchange with closely related taxa, thereby maintaining higher levels of genetic diversity than is otherwise expected for this group of “ancient asexuals”. PMID:27608044

  17. Evidence Supporting the Uptake and Genomic Incorporation of Environmental DNA in the "Ancient Asexual" Bdelloid Rotifer Philodina roseola.

    PubMed

    Bininda-Emonds, Olaf R P; Hinz, Claus; Ahlrichs, Wilko H

    2016-09-06

    Increasing evidence suggests that bdelloid rotifers regularly undergo horizontal gene transfer, apparently as a surrogate mechanism of genetic exchange in the absence of true sexual reproduction, in part because of their ability to withstand desiccation. We provide empirical support for this latter hypothesis using the bdelloid Philodina roseola, which we demonstrate to readily internalize environmental DNA in contrast to a representative monogonont rotifer (Brachionus rubens), which, like other monogononts, is facultative sexual and cannot withstand desiccation. In addition, environmental DNA that was more similar to the host DNA was retained more often and for a longer period of time. Indirect evidence (increased variance in the reproductive output of the untreated F1 generation) suggests that environmental DNA can be incorporated into the genome during desiccation and is thus heritable. Our observed fitness effects agree with sexual theory and also occurred when the animals were desiccated in groups (thereby acting as DNA donors), but not individually, indicating the mechanism could occur in nature. Thus, although DNA uptake and its genomic incorporation appears proximally related to anhydrobiosis in bdelloids, it might also facilitate accidental genetic exchange with closely related taxa, thereby maintaining higher levels of genetic diversity than is otherwise expected for this group of "ancient asexuals".

  18. Multiple horizontally acquired genes from fungal and prokaryotic donors encode cellulolytic enzymes in the bdelloid rotifer Adineta ricciae.

    PubMed

    Szydlowski, L; Boschetti, C; Crisp, A; Barbosa, E G G; Tunnacliffe, A

    2015-07-25

    The bdelloid rotifer, Adineta ricciae, an anhydrobiotic microinvertebrate, exhibits a high rate of horizontal gene transfer (HGT), with as much as 10% of its transcriptome being of foreign origin. Approximately 80% of these foreign transcripts are involved in metabolic processes, and therefore bdelloids represent a useful model for assessing the contribution of HGT to biochemical diversity. To validate this concept, we focused on cellulose digestion, an unusual activity in animals, which is represented by at least 16 genes encoding cellulolytic enzymes in A. ricciae. These genes have been acquired from a variety of different donor organisms among the bacteria and fungi, demonstrating that bdelloids use diverse genetic resources to construct a novel biochemical pathway. A variable complement of the cellulolytic gene set was found in five other bdelloid species, indicating a dynamic process of gene acquisition, duplication and loss during bdelloid evolution. For example, in A. ricciae, gene duplications have led to the formation of three copies of a gene encoding a GH45 family glycoside hydrolase, at least one of which encodes a functional enzyme; all three of these gene copies are present in a close relative, Adineta vaga, but only one copy was found in each of four Rotaria species. Furthermore, analysis of expression levels of the cellulolytic genes suggests that a bacterial-origin cellobiase is upregulated upon desiccation. In summary, bdelloid rotifers have apparently developed cellulolytic functions by the acquisition and domestication of multiple foreign genes.

  19. Gateway to genetic exchange? DNA double-strand breaks in the bdelloid rotifer Adineta vaga submitted to desiccation.

    PubMed

    Hespeels, B; Knapen, M; Hanot-Mambres, D; Heuskin, A-C; Pineux, F; LUCAS, S; Koszul, R; Van Doninck, K

    2014-07-01

    The bdelloid rotifer lineage Adineta vaga inhabits temporary habitats subjected to frequent episodes of drought. The recently published draft sequence of the genome of A. vaga revealed a peculiar genomic structure incompatible with meiosis and suggesting that DNA damage induced by desiccation may have reshaped the genomic structure of these organisms. However, the causative link between DNA damage and desiccation has never been proven to date in rotifers. To test for the hypothesis that desiccation induces DNA double-strand breaks (DSBs), we developed a protocol allowing a high survival rate of desiccated A. vaga. Using pulsed-field gel electrophoresis to monitor genomic integrity, we followed the occurrence of DSBs in dried bdelloids and observed an accumulation of these breaks with time spent in dehydrated state. These DSBs are gradually repaired upon rehydration. Even when the genome was entirely shattered into small DNA fragments by proton radiation, A. vaga individuals were able to efficiently recover from desiccation and repair a large amount of DSBs. Interestingly, when investigating the influence of UV-A and UV-B exposure on the genomic integrity of desiccated bdelloids, we observed that these natural radiations also caused important DNA DSBs, suggesting that the genome is not protected during the desiccated stage but that the repair mechanisms are extremely efficient in these intriguing organisms.

  20. Molecular evidence for broad-scale distributions in bdelloid rotifers: everything is not everywhere but most things are very widespread.

    PubMed

    Fontaneto, Diego; Barraclough, Timothy G; Chen, Kimberly; Ricci, Claudia; Herniou, Elisabeth A

    2008-07-01

    The Baas-Becking's hypothesis, also known by the term 'everything is everywhere' (EisE), states that microscopic organisms such as bacteria and protists are globally distributed and do not show biogeographical patterns, due to their high dispersal potential. We tested the prediction of the EisE hypothesis on bdelloid rotifers, microscopic animals similar to protists in size and ecology that present one of the best cases among animals for the plausibility of global dispersal. Geographical range sizes and patterns of isolation by distance were estimated for global collections of the genera Adineta and Rotaria, using different taxonomic units: (i) traditional species based on morphology, (ii) the most inclusive monophyletic lineages from a cytochrome oxidase I phylogeny comprising just a single traditional species, and (iii) genetic clusters indicative of independently evolving lineages. Although there are cases of truly cosmopolitan distribution, even at the most finely resolved taxonomic level, most genetic clusters are distributed at continental or lower scales. Nevertheless, although 'everything is not everywhere', bdelloid rotifers do display broad distributions typical of those of other microscopic organisms. Broad dispersal and large population sizes might be factors lessening the evolutionary cost of long-term abstinence from sexual reproduction in this famous group of obligate parthenogens.

  1. Combined effects of Corexit EC 9500A with secondary abiotic and biotic factors in the rotifer Brachionus plicatilis.

    PubMed

    Williams, Michael B; Powell, Mickie L; Watts, Stephen A

    2016-10-01

    We examined lethality and behavioral effects of Corexit EC 9500A (C-9500A) exposure on the model marine zooplankton Brachionus plicatilis singularly and in combination with abiotic and biotic factors. C-9500A exposure at standard husbandry conditions (17.5ppt, 24°C, 200 rotifer*mL(-1) density) identified the 24h median lethal concentration, by Probit analysis, to be 107ppm for cultured B. plicatilis. Rotifers surviving exposure to higher concentrations (100 and 150ppm) exhibited a decreased swimming velocity and a reduced net to gross movement ratio. Significant interaction between C-9500A exposure and temperature or salinity was observed. Upper thermal range was reduced and maximal salinity stress was seen as ca. 25ppt. Increased or decreased nutritional availability over the exposure period did not significantly alter mortality of B. plicatilis populations at the concentrations tested. Results from this study may be useful for predicting possible outcomes on marine zooplankton following dispersant application under diverse natural conditions.

  2. Identification criteria of the rare multi-flagellate Lophomonas blattarum: comparison of different staining techniques.

    PubMed

    Alam-Eldin, Yosra Hussein; Abdulaziz, Amany Mamdouh

    2015-09-01

    Bronchopulmonary lophomoniasis (BPL) is an emerging disease of potential importance. BPL is presented by non-specific clinical picture and is usually accompanied by immunosuppression. Culture of Lophomonas blattarum is difficult and its molecular diagnosis has not yet been developed. Therefore, microscopic examination of respiratory samples, e.g., bronchoalveolar lavage (BAL) or sputum, is the mainstay of BPL diagnosis. Creola bodies and ciliocytophthoria are two forms of bronchial cells which occur in chest diseases with non-specific clinical picture like that of BPL. Both forms could be misrecognized as multi-flagellates because of their motile cilia in the wet mounts and due to shape variability of L. blattarum in stained smears. The aim of the study is to compare different staining techniques for visualizing L. blattarum to improve the recognition and diagnosis of BPL, to distinguish respiratory epithelial cells from L. blattarum and to decide which stain is recommended in suspected cases of BPL. BAL samples from patients which contain L. blattarum, creola bodies, and ciliocytophthoria were collected then wet mounts were examined. The BAL samples were also stained by Papanicolaou (PAP), Giemsa, hematoxylin and eosin (H & E), trichrome, Gram, and Diff-Quik (DQ) stains. The different staining techniques were compared regarding the stain quality. In wet mounts, the ciliary movement was coordinate and synchronous while the flagellar movement was wavy and leaded to active swimming of L. blattarum. In stained slides, bronchial cells were characterized by the presence of basal nucleus and the terminal bar from which the cilia arise. Trichrome was the best stain in demonstration of cellular details of L. blattarum. H & E, PAP, and Giemsa stains showed good quality of stains. Gram and DQ stains showed only pale hues of L. blattarum. We recommended adding Wheatley's trichrome staining to the differential diagnosis workup of cases of non-specific chest infections

  3. Improvement of silver impregnation technique (protargol) to obtain morphological features of protists ciliates, flagellates and opalinates.

    PubMed

    da Silva-Neto, I D

    2000-08-01

    The research on ciliates, flagelates and opalinates have been widespread by the utilization of techniques employing silver impregnation (protargol), modified by several authors. However, these are time consuming and its results are variable. The present work is a variant of the technique described by Tuffrau (1964, 1967) showing some adaptations made in our laboratory. The organisms can be preserved by different fixatives (alcoholic Bouin, Stieve's fluid, 2.5% glutaraldehyde and others) and then rinsed in destilled water followed by a fast clarification by 3% sodium hypochloride. If the organism is very sensitive to hypochloride, 4% sodium lauryl sulfate may be used and then washed 3 times in distilled water. The protista can be adhered to the glass slides with Mayer's glycerinated-albumin (1 glycerin vol. to 1 or 2 albumin vol.), diluted in water at a proportion of 1:10 Cv/v., or with 1% polylysine followed by fast washes with distilled water. After the slide preparation, they were covered with a layer of 0,8% Silver proteinate. Right after that, the slide has to be placed in a glass tray lined with moist tissue and covered to prevent the proteinate to dry. The tray was placed in a incubator at 40 degrees - 50 degrees C for 30 minutes. The slides are rinsed for 1 minute. with warm (35 degrees C) distilled water. The development of the material should be done with 0.4% hydroquinone with a maximum incubation time of 1 minute. It should be developed gradually, controlling the silver impregnation intensity by observation under optical microscope. Next, rinse in distilled water for 1 minute, and then, fix in 2,5% Sodium thiosulfate. Rinse the slide for two minutes before dehydrating it in an alcoholic serial 50-100 degrees. Finally rinse the slides in xylene. Mount the slides with Entellan MerckTM or Canada balsam.

  4. Upper Arctic Ocean water masses harbor distinct communities of heterotrophic flagellates

    NASA Astrophysics Data System (ADS)

    Monier, A.; Terrado, R.; Thaler, M.; Comeau, A. M.; Medrinal, E.; Lovejoy, C.

    2013-02-01

    The ubiquity of heterotrophic flagellates (HFL) in marine waters has been recognized for several decades, but the phylogenetic diversity of these small (ca. 0.8-20 μm cell diameter), mostly phagotrophic protists in the pelagic zone of the ocean is underappreciated. Community composition of microbes, including HFL, is the result of past and current environmental selection, and different taxa may be indicative of food webs that cycle carbon and energy very differently. While all oceanic water columns can be density stratified due to the temperature and salinity characteristics of different water masses, the Arctic Ocean is particularly well stratified, with nutrients often limiting in surface waters and most photosynthetic biomass confined to a subsurface chlorophyll maximum (SCM) layer. This physically well-characterized system provided an opportunity to explore the community diversity of HFL across a wide region, and down the water column. We used high-throughput DNA sequencing techniques as a rapid means of surveying the diversity of HFL communities in the southern Beaufort Sea (Canada), targeting the surface, the SCM and just below the SCM. In addition to identifying major clades and their distribution, we explored the micro-diversity within the globally significant but uncultivated clade of marine stramenopiles (MAST-1) to examine the possibility of niche differentiation within the stratified water column. Our results strongly implied that HFL community composition was determined by water mass rather than geographical location across the Beaufort Sea. Future work should focus on the biogeochemical and ecological repercussions of different HFL communities in the face of climate driven changes to the physical structure of the Arctic Ocean.

  5. Upper Arctic Ocean water masses harbor distinct communities of heterotrophic flagellates

    NASA Astrophysics Data System (ADS)

    Monier, A.; Terrado, R.; Thaler, M.; Comeau, A.; Medrinal, E.; Lovejoy, C.

    2013-06-01

    The ubiquity of heterotrophic flagellates (HFL) in marine waters has been recognized for several decades, but the phylogenetic diversity of these small (ca. 0.8-20 μm cell diameter), mostly phagotrophic protists in the upper pelagic zone of the ocean is underappreciated. Community composition of microbes, including HFL, is the result of past and current environmental selection, and different taxa may be indicative of food webs that cycle carbon and energy very differently. While all oceanic water columns can be density stratified due to the temperature and salinity characteristics of different water masses, the Arctic Ocean is particularly well stratified, with nutrients often limiting in surface waters and most photosynthetic biomass confined to a subsurface chlorophyll maximum layer, where light and nutrients are both available. This physically well-characterized system provided an opportunity to explore the community diversity of HFL from different water masses within the water column. We used high-throughput DNA sequencing techniques as a rapid means of surveying the diversity of HFL communities in the southern Beaufort Sea (Canada), targeting the surface, the subsurface chlorophyll maximum layer (SCM) and just below the SCM. In addition to identifying major clades and their distribution, we explored the micro-diversity within the globally significant but uncultivated clade of marine stramenopiles (MAST-1) to examine the possibility of niche differentiation within the stratified water column. Our results strongly suggested that HFL community composition was determined by water mass rather than geographical location across the Beaufort Sea. Future work should focus on the biogeochemical and ecological repercussions of different HFL communities in the face of climate-driven changes to the physical structure of the Arctic Ocean.

  6. The Structure of the Mitotic Spindle and Nucleolus during Mitosis in the Amebo-Flagellate Naegleria

    PubMed Central

    Walsh, Charles J.

    2012-01-01

    Mitosis in the amebo-flagellate Naegleria pringsheimi is acentrosomal and closed (the nuclear membrane does not break down). The large central nucleolus, which occupies about 20% of the nuclear volume, persists throughout the cell cycle. At mitosis, the nucleolus divides and moves to the poles in association with the chromosomes. The structure of the mitotic spindle and its relationship to the nucleolus are unknown. To identify the origin and structure of the mitotic spindle, its relationship to the nucleolus and to further understand the influence of persistent nucleoli on cellular division in acentriolar organisms like Naegleria, three-dimensional reconstructions of the mitotic spindle and nucleolus were carried out using confocal microscopy. Monoclonal antibodies against three different nucleolar regions and α-tubulin were used to image the nucleolus and mitotic spindle. Microtubules were restricted to the nucleolus beginning with the earliest prophase spindle microtubules. Early spindle microtubules were seen as short rods on the surface of the nucleolus. Elongation of the spindle microtubules resulted in a rough cage of microtubules surrounding the nucleolus. At metaphase, the mitotic spindle formed a broad band completely embedded within the nucleolus. The nucleolus separated into two discreet masses connected by a dense band of microtubules as the spindle elongated. At telophase, the distal ends of the mitotic spindle were still completely embedded within the daughter nucleoli. Pixel by pixel comparison of tubulin and nucleolar protein fluorescence showed 70% or more of tubulin co-localized with nucleolar proteins by early prophase. These observations suggest a model in which specific nucleolar binding sites for microtubules allow mitotic spindle formation and attachment. The fact that a significant mass of nucleolar material precedes the chromosomes as the mitotic spindle elongates suggests that spindle elongation drives nucleolar division. PMID:22493714

  7. The system of contractile vacuoles in the green alga Mesostigma viride (Streptophyta).

    PubMed

    Buchmann, Karin; Becker, Burkhard

    2009-08-01

    The contractile vacuole (CV) is an osmoregulatory organelle which is found in many protists. We have investigated the structure and function of the CV in the green alga Mesostigma viride by light (video) and serial section electron microscopy. Mesostigma is the only known flagellate streptophyte (charophycean green algae and land plants) and therefore of great importance for our understanding of the evolution of streptophytes. The entire CV system of Mesostigma has been reconstructed 3-dimensionally for three cells. Based on light microscopy cells contain an average of 8 CVs. The maximal diameter of a CV in Mesostigma was 1.5 microm and the expulsion interval 24.1s in 10 mosM medium. Video microscopy revealed the system of CVs to be very dynamic with individual CVs connecting temporarily or fusing completely with each other. Electron microscopy confirmed these observations and showed coated vesicles to be predominantly associated with large CVs. No expulsion pore was observed by electron microscopy. Instead we encountered close contact zones of approximately 150 nm diameter, which we propose to be the site of water expulsion. A model for the function of CVs in Mesostigma is presented.

  8. Neuroprotective Effects of Marine Algae

    PubMed Central

    Pangestuti, Ratih; Kim, Se-Kwon

    2011-01-01

    The marine environment is known as a rich source of chemical structures with numerous beneficial health effects. Among marine organisms, marine algae have been identified as an under-exploited plant resource, although they have long been recognized as valuable sources of structurally diverse bioactive compounds. Presently, several lines of studies have provided insight into biological activities and neuroprotective effects of marine algae including antioxidant, anti-neuroinflammatory, cholinesterase inhibitory activity and the inhibition of neuronal death. Hence, marine algae have great potential to be used for neuroprotection as part of pharmaceuticals, nutraceuticals and functional foods. This contribution presents an overview of marine algal neuroprotective effects and their potential application in neuroprotection. PMID:21673890

  9. Polysaccharides of the red algae.

    PubMed

    Usov, Anatolii I

    2011-01-01

    Red algae (Rhodophyta) are known as the source of unique sulfated galactans, such as agar, agarose, and carrageenans. The wide practical uses of these polysaccharides are based on their ability to form strong gels in aqueous solutions. Gelling polysaccharides usually have molecules built up of repeating disaccharide units with a regular distribution of sulfate groups, but most of the red algal species contain more complex galactans devoid of gelling ability because of various deviations from the regular structure. Moreover, several red algae may contain sulfated mannans or neutral xylans instead of sulfated galactans as the main structural polysaccharides. This chapter is devoted to a description of the structural diversity of polysaccharides found in the red algae, with special emphasis on the methods of structural analysis of sulfated galactans. In addition to the structural information, some data on the possible use of red algal polysaccharides as biologically active polymers or as taxonomic markers are briefly discussed.

  10. Use of Probiotic Bacillus spp. in Rotifer (Brachionus plicatilis) and Artemia (Artemia urmiana) Enrichment: Effects on Growth and Survival of Pacific White Shrimp, Litopenaeus vannamei, Larvae.

    PubMed

    Jamali, Hadi; Imani, Ahmad; Abdollahi, Daruosh; Roozbehfar, Reza; Isari, Amin

    2015-06-01

    This study was to evaluate the effect of a preparation of Bacillus probiotic (Bacillus licheniformis and B. subtilis, 1:1) on growth and survival rate of Pacific white shrimp, Litopenaeus vannamei larvae. The larvae were fed on Artemia urmiana nauplii and Brachionus plicatilis enriched with the probiotic preparation at 1 × 10(6) CFU mL(-1) rate. The experimental setup was completely randomized design comprised of six treatments, namely solo Artemia nauplii (A) or rotifer (R), Artemia nauplii and rotifer without any enrichment (A + R), Artemia nauplii enrichment with probiotic bacilli (Bacillus licheniformis and B. subtilis) (A + B), rotifer enrichment with probiotic bacilli (R + B) and enriched Artemia nauplii and rotifer (A + R + B). All treatments were performed in triplicate. Chemical parameters of rearing water viz. pH, salinity and temperature were 7.5-8, 30-31 ppt and 31-32 °C, respectively. Photoperiod was 16L:8D. Shrimp larvae were fed Artemia nauplii and rotifers at 5-20 and 10-40 individuals per shrimp larvae four times a day, respectively. Growth and survival rate of larvae were determined at MII, MIII, PL1, PL4, PL7 and PL10 stages. Larvae in A + R + B treatment showed the highest total length (10.89 ± 0.51 mm), weight (674 ± 73 μg) and survival rate (65% ± 3.5). Lowest total length, weight and survival rate (7.96 ± 0.63 mm, 493 ± 52 μg and 24.5 ± 2.4%, respectively) were recorded in treatment B larvae. We concluded that Bacillus probiotic can improve growth and survival rate of Pacific white shrimp larvae without conceivably undesirable effects.

  11. Chitinous fibrils in the lorica of the flagellate chrysophyte Poteriochromonas stipitata (syn. Ochromonas malhamensis)

    PubMed Central

    1977-01-01

    Ordered microfibrils are formed on the membrane of the cytoplasmic tail of the alga Poteriochromonas after attachment to a substrate. The ultrastructure of native and extracted stalk fibrils was studied with electron microscope methods. In addition, the structural polysaccharide was characterized by hydrolyses, separation of the monomers by thin- layer chromatography, gas-liquid chromatography and amino acid analysis, and by X-ray diffraction. The alkali-resistant fibrils yielded mostly glucosamine upon extensive hydrolysis, and showed X-ray diffraction patterns similar to those of fugal chitin. It is concluded that the resistant core of the fibrils is chitinous. PMID:858740

  12. Formation of algae growth constitutive relations for improved algae modeling.

    SciTech Connect

    Gharagozloo, Patricia E.; Drewry, Jessica Louise.

    2013-01-01

    This SAND report summarizes research conducted as a part of a two year Laboratory Directed Research and Development (LDRD) project to improve our abilities to model algal cultivation. Algae-based biofuels have generated much excitement due to their potentially large oil yield from relatively small land use and without interfering with the food or water supply. Algae mitigate atmospheric CO2 through metabolism. Efficient production of algal biofuels could reduce dependence on foreign oil by providing a domestic renewable energy source. Important factors controlling algal productivity include temperature, nutrient concentrations, salinity, pH, and the light-to-biomass conversion rate. Computational models allow for inexpensive predictions of algae growth kinetics in these non-ideal conditions for various bioreactor sizes and geometries without the need for multiple expensive measurement setups. However, these models need to be calibrated for each algal strain. In this work, we conduct a parametric study of key marine algae strains and apply the findings to a computational model.

  13. Microscopic Gardens: A Close Look at Algae.

    ERIC Educational Resources Information Center

    Foote, Mary Ann

    1983-01-01

    Describes classroom activities using algae, including demonstration of eutrophication, examination of mating strains, and activities with Euglena. Includes on algal morphology/physiology, types of algae, and field sources for collecting these organisms. (JN)

  14. Toll-like receptor 5 is not essential for the promotion of secretory immunoglobulin A antibody responses to flagellated bacteria.

    PubMed

    Hashizume-Takizawa, Tomomi; Yamamoto, Masafumi

    2015-12-01

    Toll-like receptor 5 recognizes bacterial flagellin, plays a critical role in innate immunity, and contributes to flagellin-specific humoral immunity. Further, TLR5-expressing dendritic cells play an important role in IgA synthesis in the intestine; however, the contribution of TLR5 to antigen (Ag)-specific mucosal immunity remains unclear. Thus, whether TLR5 is essential for the induction of intestinal secretory (S)IgA antibody (Ab) responses against flagellin and bacterial Ags attached to the bacterial surface in response to an oral flagellated bacterium, Salmonella, was explored in this study. Our results indicate that when TLR5 knockout (TLR5(-/-)) mice are orally immunized with recombinant Salmonella expressing fragment C of tetanus toxin (rSalmonella-Tox C), tetanus toxoid (TT)- and flagellin (FliC)-specific systemic IgG and intestinal SIgA Abs are elicited. The numbers of TT-specific IgG Ab-forming cells (AFCs) in the spleen and IgA AFCs in the lamina propria (LP) of TLR5(-/-) mice were comparable to those in wild-type mice. rSalmonella-Tox C was equally disseminated in TLR5(-/-) mice, TLR5(-/-) mice lacking Peyer's patches (PPs), and wild-type mice. In contrast, TLR5(-/-) PP-null mice failed to induce TT- and FliC-specific SIgA Abs in the intestine and showed significantly reduced numbers of TT-specific IgA AFCs in the LP. These results suggest that TLR5 is dispensable for the induction of flagellin and surface Ag-specific systemic and mucosal immunity against oral flagellated bacteria. Rather, pathogen recognition, which occurs in PPs, is a prerequisite for the induction of mucosal immunity against flagellated bacteria. PMID:26564803

  15. Pirsonia guinardiae, gen. et spec. nov.: A parasitic flagellate on the marine diatom Guinardia flaccida with an unusual mode of food uptake

    NASA Astrophysics Data System (ADS)

    Schnepf, E.; Drebes, G.; Elbrächter, M.

    1990-06-01

    Pirsonia guinardiae gen. et spec. nov. was discovered as a parasite on Guinardia flaccida in the North Sea near List/Sylt during a bloom of this centric planktonic diatom. It is a colourless, small flagellate with an oblique cell apex and two subapically inserting flagella of different length and different orientation. The flagellates attach to a host cell and form an antapical process which pierces the diatom frustule and develops inside into a “trophosome”, consisting of a proximal digestion vacuole and distal pseudopodia which phagocytise host cytoplasm. The main body, the “auxosome”, remains outside the host cell. The trophosome persists for some time after the detachment of the auxosome or its derivatives. There are two types of Pirsonia guinardiae. Type A attaches to the valvae as well as to the girdle region, the auxosome remains flagellated and generally detaches after the feeding process to divide twice (seldom 3 times). Thick-walled (resting?) cysts are formed. Occasionally, a fusion of two sister cells has been observed. Type B attaches only to the valvae; the auxosome lacks flagella; it divides during the feeding process to give rise to a bouquet of 8 to more than 50 daughter cells which become flagellated when they detach. The taxonomical position of the flagellate is discussed. Diagnoses of genus and species are given.

  16. The Effects of Petroleum Hydrocarbons on Algae Can Be Reversed in the Presence of a Primary Consumer.

    PubMed

    Wang, Changyou; Zhang, Yong; Li, Hongli; Xing, Wenhui; Yu, Hua

    2015-09-01

    The ecotoxicological effects of a mixture of petroleum hydrocarbons were tested on densities of two algae, Platymonas helgolandica var. tsingtaoensis and Isochrysis galbana, and of a rotifer, Brachionus plicatilis, by single-species and customized community experiments. Test concentrations ranged from 0 to 100 mg L(-1), while five to seven treatments were assessed in triplicate within 1 month. A significant decrease in densities during single-species toxicity tests were found when concentrations of petroleum hydrocarbons were above 1.0 mg L(-1). However, equilibrium densities of algae in the customized community showed a different pattern, which increased with concentration and reached a peak at 20.0 mg L(-1). The community-based no observed effect concentration (NOEC; 1.0 mg L(-1)) was different from the NOEC derived by single-species toxic tests (0.25 mg L(-1)). This demonstrates that ecotoxicological effects on plankton as part of a community is significantly different from single-species toxicity tests owing to ecological interactions.

  17. 21 CFR 184.1120 - Brown algae.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Brown algae. 184.1120 Section 184.1120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1120 Brown algae. (a) Brown algae are seaweeds of the species...

  18. 21 CFR 184.1120 - Brown algae.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Brown algae. 184.1120 Section 184.1120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1120 Brown algae. (a) Brown algae are seaweeds of the species...

  19. 21 CFR 184.1120 - Brown algae.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Brown algae. 184.1120 Section 184.1120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1120 Brown algae. (a) Brown algae are seaweeds of the species...

  20. 21 CFR 184.1120 - Brown algae.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Brown algae. 184.1120 Section 184.1120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1120 Brown algae. (a) Brown algae are seaweeds of the species...

  1. 21 CFR 184.1121 - Red algae.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Red algae. 184.1121 Section 184.1121 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1121 Red algae. (a) Red algae are seaweeds of the species...

  2. 21 CFR 184.1121 - Red algae.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Red algae. 184.1121 Section 184.1121 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1121 Red algae. (a) Red algae are seaweeds of the species...

  3. 21 CFR 184.1121 - Red algae.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Red algae. 184.1121 Section 184.1121 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1121 Red algae. (a) Red algae are seaweeds of the species...

  4. 21 CFR 184.1121 - Red algae.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Red algae. 184.1121 Section 184.1121 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1121 Red algae. (a) Red algae are seaweeds of the species...

  5. 21 CFR 184.1121 - Red algae.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Red algae. 184.1121 Section 184.1121 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT FOOD....1121 Red algae. (a) Red algae are seaweeds of the species Gloiopeltis furcata, Porphyra...

  6. 21 CFR 184.1120 - Brown algae.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Brown algae. 184.1120 Section 184.1120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT FOOD....1120 Brown algae. (a) Brown algae are seaweeds of the species Analipus japonicus, Eisenia...

  7. Bdelloid Rotifers from Lakes above 1700 m in Western Italian Alps, with Taxonomic Notes on Dissotrocha macrostyla

    NASA Astrophysics Data System (ADS)

    Fontaneto, Diego; Melone, Giulio

    2003-11-01

    Benthic and periphytic bdelloid communities from 16 alpine lakes from 1700 to 2850 m above sea level in Sesia Valley (Piedmont region, North-western Italy), sampled during summer 2001 and 2002, were analyzed. Seventeen species were identified from these species-poor communities, with 1 to 6 species each. Dissotrocha macrostyla and Philodina citrina were the most common species, present in 10 lakes while 9 species were collected from one lake only. New morphological details from S.E.M. pictures of Dissotrocha macrostyla revealed that Dissotrocha macrostyla tuberculata (Gosse, 1886) is only a seasonal morphotype. Its different appearance is due to the presence of locally distributed microscopic mucous bubbles (diameter 1.41 +/- 0.18 m) on the trunk surface, produced by the rotifer itself under stressful conditions.

  8. Biological importance of marine algae

    PubMed Central

    El Gamal, Ali A.

    2009-01-01

    Marine organisms are potentially prolific sources of highly bioactive secondary metabolites that might represent useful leads in the development of new pharmaceutical agents. Algae can be classified into two main groups; first one is the microalgae, which includes blue green algae, dinoflagellates, bacillariophyta (diatoms)… etc., and second one is macroalgae (seaweeds) which includes green, brown and red algae. The microalgae phyla have been recognized to provide chemical and pharmacological novelty and diversity. Moreover, microalgae are considered as the actual producers of some highly bioactive compounds found in marine resources. Red algae are considered as the most important source of many biologically active metabolites in comparison to other algal classes. Seaweeds are used for great number of application by man. The principal use of seaweeds as a source of human food and as a source of gums (phycocollides). Phycocolloides like agar agar, alginic acid and carrageenan are primarily constituents of brown and red algal cell walls and are widely used in industry. PMID:23960716

  9. Magnetite and Magnetotaxis in Algae

    PubMed Central

    de Araujo, F. F. Torres; Pires, M. A.; Frankel, R. B.; Bicudo, C. E. M.

    1986-01-01

    Magnetotactic algae of the genus Anisonema (Euglenophyceae) have been isolated from a coastal mangrove swamp in northeastern Brazil. The magnetotactic response is based on a permanent magnetic dipole moment per cell ∼7 10-10 emu. Each cell contains many magnetite (Fe3O4) particles organized in chains. ImagesFIGURE 2FIGURE 1FIGURE 3 PMID:19431684

  10. Algae. LC Science Tracer Bullet.

    ERIC Educational Resources Information Center

    Niskern, Diana, Comp.

    The plants and plantlike organisms informally grouped together as algae show great diversity of form and size and occur in a wide variety of habitats. These extremely important photosynthesizers are also economically significant. For example, some species contaminate water supplies; others provide food for aquatic animals and for man; still others…

  11. Acute toxicity tests using rotifers. 4. Effects of cyst age, temperature, and salinity on the sensitivity of Brachionus calyciflorus

    SciTech Connect

    Snell, T.W.; Moffat, B.D.; Janssen, C.; Persoone, G. )

    1991-06-01

    Several aspects of the response to toxicants using a standardized toxicity test with the freshwater rotifer Brachionus calyciflorus are described. Test animals are obtained by hatching cysts which produce animals of similar age and physiological condition. The acute toxicity of 28 compounds is described with 24-hr LC50's. The LC50's span five orders of magnitude, from silver at 0.008 mg.liter-1 to benzene at more than 1000 mg.liter-1. Control mortality in 84 tests averaged 2% with a standard deviation of 3%, indicating very consistent test sensitivity. Only once in 84 trials did a test fail because of excessive control mortality, yielding a failure rate of 1.2%. Cyst age from 0 to 18 months had no effect on the sensitivity of neonates to reference toxicants. Both high and low temperatures increased rotifer sensitivity to reference toxicants. Copper sensitivity was greater at 10, 25, and 30 degrees C compared with results at 20 degrees C. Likewise, sodium pentachlorophenol toxicity was greater at 10 and 30 degrees C compared with results at 20 degrees C. Survivorship curves at 25 degrees C of neonates under control conditions indicated that mortality begins at about 30 hr. This places a practical limit on toxicant exposure for the assay of 24 hr. B. calyciflorus cysts hatch at salinities up to 5 ppt and acute toxicity tests using pentachlorophenol at this salinity yielded LC50's about one-half those of standard freshwater. B. calyciflorus is preferred over Brachionus plicatilis for toxicity tests in salinities up to 5 ppt because it is consistently more sensitive.

  12. Impact of several harmful algal bloom (HAB) causing species, on life history characteristics of rotifer Brachionus plicatilis Müller

    NASA Astrophysics Data System (ADS)

    Lin, Jianing; Yan, Tian; Zhang, Qingchun; Zhou, Mingjiang

    2016-07-01

    In recent years, harmful algal blooms (HABs) have occurred frequently along the coast of China, and have been exhibiting succession from diatom- to dinoflagellate-dominated blooms. To examine the effects of different diatom and dinoflagellate HABs, the life history parameters of rotifers ( Brachionus plicatilis Müller) were measured after exposure to different concentrations of HAB species. The HAB species examined included a diatom ( Skeletonema costatum) and four dinoflagellates ( Prorocentrum donghaiense, Alexandrium catenella, Prorocentrum lima and Karlodinium veneficum). Compared with the control treatment (CT), the diatom S. costatum showed no adverse impacts on rotifers. Exposure to dinoflagellates at densities equivalent to those measured in the field resulted in a reduction in all the life history parameters measured. This included a reduction in: lifetime egg production (CT: 20.34 eggs/ind.) reduced to 10.11, 3.22, 4.17, 7.16 eggs/ind., life span (CT: 394.53 h) reduced to 261.11, 162.90, 203.67, 196 h, net reproductive rate (CT: 19.51/ind.) reduced to 3.01, 1.26, 3.53, 5.96/ind., finite rate of increase (CT: 1.47/d) reduced to 1.16, 1.03, 1.33, 1.38/d, and intrinsic rate of population increase (CT: 0.39/d) reduced to 0.15, 0.03, 0.28, 0.32/d, for the dinoflagellates P. donghaiense, A. catenella, P. lima and K. veneficum, respectively. The results showed that the diatom S. costatum had no detrimental consequences on the reproduction and growth of B. plicatilis, however, the four dinoflagellates tested did show adverse effects. This suggests that dinoflagellate HABs may suppress microzooplankton, resulting in an increase in algal numbers.

  13. Intracellular haemolytic agents of Heterocapsa circularisquama exhibit toxic effects on H. circularisquama cells themselves and suppress both cell-mediated haemolytic activity and toxicity to rotifers (Brachionus plicatilis).

    PubMed

    Nishiguchi, Tomoki; Cho, Kichul; Yasutomi, Masumi; Ueno, Mikinori; Yamaguchi, Kenichi; Basti, Leila; Yamasaki, Yasuhiro; Takeshita, Satoshi; Kim, Daekyung; Oda, Tatsuya

    2016-10-01

    A harmful dinoflagellate, Heterocapsa circularisquama, is highly toxic to shellfish and the zooplankton rotifer Brachionus plicatilis. A previous study found that H. circularisquama has both light-dependent and -independent haemolytic agents, which might be responsible for its toxicity. Detailed analysis of the haemolytic activity of H. circularisquama suggested that light-independent haemolytic activity was mediated mainly through intact cells, whereas light-dependent haemolytic activity was mediated by intracellular agents which can be discharged from ruptured cells. Because H. circularisquama showed similar toxicity to rotifers regardless of the light conditions, and because ultrasonic ruptured H. circularisquama cells showed no significant toxicity to rotifers, it was suggested that live cell-mediated light-independent haemolytic activity is a major factor responsible for the observed toxicity to rotifers. Interestingly, the ultrasonic-ruptured cells of H. circularisquama suppressed their own lethal effect on the rotifers. Analysis of samples of the cell contents (supernatant) and cell fragments (precipitate) prepared from the ruptured H. circularisquama cells indicated that the cell contents contain inhibitors for the light-independent cell-mediated haemolytic activity, toxins affecting H. circularisquama cells themselves, as well as light-dependent haemolytic agents. Ethanol extract prepared from H. circularisquama, which is supposed to contain a porphyrin derivative that displays photosensitising haemolytic activity, showed potent toxicity to Chattonella marina, Chattonella antiqua, and Karenia mikimotoi, as well as to H. circularisquama at the concentration range at which no significant toxicity to rotifers was observed. Analysis on a column of Sephadex LH-20 revealed that light-dependent haemolytic activity and inhibitory activity on cell-mediated light-independent haemolytic activity existed in two separate fractions (f-2 and f-3), suggesting that both

  14. Intracellular haemolytic agents of Heterocapsa circularisquama exhibit toxic effects on H. circularisquama cells themselves and suppress both cell-mediated haemolytic activity and toxicity to rotifers (Brachionus plicatilis).

    PubMed

    Nishiguchi, Tomoki; Cho, Kichul; Yasutomi, Masumi; Ueno, Mikinori; Yamaguchi, Kenichi; Basti, Leila; Yamasaki, Yasuhiro; Takeshita, Satoshi; Kim, Daekyung; Oda, Tatsuya

    2016-10-01

    A harmful dinoflagellate, Heterocapsa circularisquama, is highly toxic to shellfish and the zooplankton rotifer Brachionus plicatilis. A previous study found that H. circularisquama has both light-dependent and -independent haemolytic agents, which might be responsible for its toxicity. Detailed analysis of the haemolytic activity of H. circularisquama suggested that light-independent haemolytic activity was mediated mainly through intact cells, whereas light-dependent haemolytic activity was mediated by intracellular agents which can be discharged from ruptured cells. Because H. circularisquama showed similar toxicity to rotifers regardless of the light conditions, and because ultrasonic ruptured H. circularisquama cells showed no significant toxicity to rotifers, it was suggested that live cell-mediated light-independent haemolytic activity is a major factor responsible for the observed toxicity to rotifers. Interestingly, the ultrasonic-ruptured cells of H. circularisquama suppressed their own lethal effect on the rotifers. Analysis of samples of the cell contents (supernatant) and cell fragments (precipitate) prepared from the ruptured H. circularisquama cells indicated that the cell contents contain inhibitors for the light-independent cell-mediated haemolytic activity, toxins affecting H. circularisquama cells themselves, as well as light-dependent haemolytic agents. Ethanol extract prepared from H. circularisquama, which is supposed to contain a porphyrin derivative that displays photosensitising haemolytic activity, showed potent toxicity to Chattonella marina, Chattonella antiqua, and Karenia mikimotoi, as well as to H. circularisquama at the concentration range at which no significant toxicity to rotifers was observed. Analysis on a column of Sephadex LH-20 revealed that light-dependent haemolytic activity and inhibitory activity on cell-mediated light-independent haemolytic activity existed in two separate fractions (f-2 and f-3), suggesting that both

  15. The candidate phylum 'Termite Group 1' of bacteria: phylogenetic diversity, distribution, and endosymbiont members of various gut flagellated protists.

    PubMed

    Ohkuma, Moriya; Sato, Tomoyuki; Noda, Satoko; Ui, Sadaharu; Kudo, Toshiaki; Hongoh, Yuichi

    2007-06-01

    The candidate phylum 'Termite Group 1' (TG1) of bacteria, which is abundant in termite guts but has no culturable representative, was investigated with respect to the in situ localization, distribution, and diversity. Based on the 16S rRNA gene sequence analyses and FISH in termite guts, a number of lineages of TG1 members were identified as endosymbionts of a variety of gut flagellated protists from the orders Trichonymphida, Cristamonadida, and Oxymonadida that are mostly unique to termites. However, the survey in various environments using specific PCR primers revealed that TG1 members were also present in termites, a cockroach, and the bovine rumen that typically lack these protist orders. Most of the TG1 members from gut flagellates, termites, cockroaches, and the rumen formed a monophyletic subcluster that showed a shallow branching pattern in the phylogenetic tree, suggesting their recent diversification. Although endosymbionts of the same protist genera tended to be closely related, the endosymbiont lineages were often independent of the higher level classifications of their host protist and were dispersed in the phylogenetic tree. It appears that their cospeciation is not the sole rule for the diversification of TG1 members of endosymbionts. PMID:17391329

  16. The dependence of the swimming efficiency of multi-flagellated bacteria on the geometric arrangement of flagella

    NASA Astrophysics Data System (ADS)

    Watari, Nobuhiko; Larson, Ronald

    2010-11-01

    Multi-flagellated bacteria, such as Escherichia coli, often have flagella attached at random locations to the cell body. To study the effect of the number of flagella and the geometric arrangement of them to the swimming efficiency, we develop a simulation method using a bead-spring model to account for the hydrodynamic and the mechanical interactions between multiple flagella and the cell body. First, a modeled bacterium is constructed using beads, which represent the hydrodynamic drag centers of the geometric elements of the bacterium. This modeled bacterium swims by rotating the flagella with constant torques at the bases of them. We have found that for modeled bacteria with two flagella, the swimming speed varies by 30% depending on the position of the base of the flagellum along the cell body, which affects the tightness of the bundling. We have also found that overly rigid flagella can slow migration by inhibiting flagellar bundling, since bundling requires some adjustment in flagellar shape to compensate for helical phase miss-match produced by irregular flagellar positioning. In general, by changing the geometric arrangement and the number of flagella, our simulation enables us to determine the optimal designing of a flagellated micro-swimmer.

  17. Transcriptional regulation of coordinate changes in flagellar mRNAs during differentiation of Naegleria gruberi amoebae into flagellates

    SciTech Connect

    Lee, J.H.; Walsh, C.J.

    1988-06-01

    The nuclear run-on technique was used to measure the rate of transcription of flagellar genes during the differentiation of Naegleria gruberi amebae into flagellates. Synthesis of mRNAs for the axonemal proteins ..cap alpha..- and BETA-tubulin and flagellar calmodulin, as well as a coordinately regulated poly(A)/sup +/ RNA that codes for an unidentified protein, showed transient increases averaging 22-fold. The rate of synthesis of two poly(A)/sup +/ RNAs common to ameobae and flagellates was low until the transcription of the flagellar genes began to decline, at which time synthesis of the RNAs found in ameobae increased 3- to 10-fold. The observed changes in the rate of transcription can account quantitatively for the 20-fold increase in flagellar mRNA concentration during the differentiation. The data for the flagellar calmodulin gene demonstrate transcriptional regulation for a nontubulin axonemal protein. The data also demonstrate at least two programs of transcriptional regulation during the differentiation and raise the intriguing possibility that some significant fraction of the nearly 200 different proteins of the flagellar axoneme is transcriptionally regulated during the 1 h it takes N. gruberi amebae to form visible flagella.

  18. Tsukubamonas globosa n. gen., n. sp., a novel excavate flagellate possibly holding a key for the early evolution in "Discoba".

    PubMed

    Yabuki, Akinori; Nakayama, Takeshi; Yubuki, Naoji; Hashimoto, Tetsuo; Ishida, Ken-Ichiro; Inagaki, Yuji

    2011-01-01

    We report the ultrastructure and phylogenetic position of a free-living heterotrophic flagellate, Tsukubamonas globosa n. gen., n. sp. This flagellate was isolated from a pond in the University of Tsukuba, Japan. Under light microscopy, the spherical vegetative cells were naked and highly vacuolated, and always swam with rotating motion. Electron microscopic observations revealed that T. globosa possessed a ventral feeding groove, which is one of the hallmark characteristics of the supergroup Excavata. The position of T. globosa was unresolved in the small subunit ribosomal RNA phylogeny. On the other hand, a multigene phylogeny using α-tubulin, β-tubulin, actin, heat shock protein 90, and translation elongation factor 2 robustly united T. globosa with members of the "Discoba" clade of Excavata, composed of jakobids, euglenozoans, and heteroloboseans, although the precise position of T. globosa in this clade remained unresolved. Our detailed morphological comparisons elucidated that T. globosa possessed a novel set of morphological features, and could not be classified into any taxa in the Discoba clade. Instead we classified T. globosa into Tsukubamonadidae n. fam. under Tsukubamonadida n. ord.

  19. Benthic flagellates and ciliates in fine freshwater sediments: Calibration of a live counting procedure and estimation of their abundances.

    PubMed

    Gasol, J M

    1993-05-01

    Despite the recognized importance of protozoans (flagellates and ciliates) as predators of bacteria, there are very few estimates of their abundance in fine sediments of freshwater lakes. This is due, in part, to the lack of a standard methodology. Because of the low concentration of protists in relation to particles, epifluorescence counts can not always be used. Instead, dilution followed by live counting was used to solve the masking by sediment particles. One to twenty μ1 sample aliquots were diluted with filtered lake water in a Palmer-Maloney counting slide. Four to eight replicates were sufficient to minimize the counting error, while minimizing effort. The method is highly replicable and could potentially be calibrated for different sediment types because sediment masking depends on the mean particle size of the sediment. When this method was applied in a survey of benthic sites in Quebec lakes, flagellate abundances were found to range from 100 to 180,000 cells ml(-1), while ciliate numbers ranged from 26 to 11,000 cells ml(-1). Bacteria are 105 to 10(7) times more abundant than protists and, thus, the impact of these protists on sediment bacterial dynamics is likely to be minimal.

  20. Primer pairs for the specific environmental detection and T-RFLP analysis of the ubiquitous flagellate taxa Chrysophyceae and Kinetoplastea.

    PubMed

    Glaser, Karin; Kuppardt, Anke; Krohn, Sandra; Heidtmann, Anett; Harms, Hauke; Chatzinotas, Antonis

    2014-05-01

    Bacterivorous protists play a key role in microbial soil food webs, however due to the lack of specific PCR protocols targeting selected protist taxa, knowledge on the diversity and dynamics of these groups is scarce. We developed specific PCR primers in combination with a T-RFLP protocol for the cultivation-independent analysis of two important taxa of bacterivorous flagellates, the Chrysophyceae and Kinetoplastea, in soil samples. Sequence analysis of clone libraries originating from two soils in temperate regions demonstrated the specificity of the respective primer pairs. Clone sequences affiliating to the Chrysophyceae mainly clustered within the clade C2, which has been known so far for its presence mainly in cold climatic regions, whereas Kinetoplastea sequences were mainly related to the Neobodonid clade. Based on an in silico restriction analysis of database sequence entries, suitable restriction enzymes for a T-RFLP approach were selected. This in silico approach revealed the necessity to use a combination of two restriction enzymes for T-RFLP analysis of the Chrysophyceae. Soil T-RFLP profiles reflected all T-RFs of the clone library sequences obtained from the same soils and allowed to distinguish flagellate communities from different sites. We propose to use these primer pairs for PCR detection and rapid fingerprint screening in environmental samples and envisage their use also for quantitative PCR or next generation sequencing approaches.

  1. The candidate phylum 'Termite Group 1' of bacteria: phylogenetic diversity, distribution, and endosymbiont members of various gut flagellated protists.

    PubMed

    Ohkuma, Moriya; Sato, Tomoyuki; Noda, Satoko; Ui, Sadaharu; Kudo, Toshiaki; Hongoh, Yuichi

    2007-06-01

    The candidate phylum 'Termite Group 1' (TG1) of bacteria, which is abundant in termite guts but has no culturable representative, was investigated with respect to the in situ localization, distribution, and diversity. Based on the 16S rRNA gene sequence analyses and FISH in termite guts, a number of lineages of TG1 members were identified as endosymbionts of a variety of gut flagellated protists from the orders Trichonymphida, Cristamonadida, and Oxymonadida that are mostly unique to termites. However, the survey in various environments using specific PCR primers revealed that TG1 members were also present in termites, a cockroach, and the bovine rumen that typically lack these protist orders. Most of the TG1 members from gut flagellates, termites, cockroaches, and the rumen formed a monophyletic subcluster that showed a shallow branching pattern in the phylogenetic tree, suggesting their recent diversification. Although endosymbionts of the same protist genera tended to be closely related, the endosymbiont lineages were often independent of the higher level classifications of their host protist and were dispersed in the phylogenetic tree. It appears that their cospeciation is not the sole rule for the diversification of TG1 members of endosymbionts.

  2. The pathogenic amoeboflagellate Naegleria fowleri: environmental isolations, competitors, ecologic interactions, and the flagellate-empty habitat hypothesis.

    PubMed

    Griffin, J L

    1983-05-01

    From several surveys of environmental sites, the virulent human pathogen, Naegleria fowleri, was isolated from a pond in Georgia, a sewage treatment plant in Missouri, and from the Potomac and Anacostia rivers near and in Washington, D.C. Widely scattered, sparse populations seemed only a potential threat to human health at the time of sampling. The data support an estimate that the sites sampled contain 10,000 typical, low temperature, bactivorous amoebae for each heat tolerant amoeba able to grow at 45 degrees C. Heat tolerant competitors were much more common than N. fowleri. Naegleria lovaniensis, which is heat tolerant but nonpathogenic, was isolated from and downstream from an open air thermal pollution temperature gradient. Hot piles of composting sewage sludge yielded no amoeboflagellates, many heat tolerant (45-49 degrees C) amoebae, and one thermophilic (52 degrees C) Acanthamoeba. Features of the methods used include two-stage incubation to increase isolation of sparse organisms and distinction of N. fowleri from almost all other amoebae on agar plates. The flagellate-empty habitat hypothesis postulates a general model in which human intervention and/or natural events remove usual competitors and the ability to transform to a motile flagellate confers an advantage in recolonizing.

  3. The remote sensing of algae

    NASA Technical Reports Server (NTRS)

    Thorne, J. F.

    1977-01-01

    State agencies need rapid, synoptic and inexpensive methods for lake assessment to comply with the 1972 Amendments to the Federal Water Pollution Control Act. Low altitude aerial photography may be useful in providing information on algal type and quantity. Photography must be calibrated properly to remove sources of error including airlight, surface reflectance and scene-to-scene illumination differences. A 550-nm narrow wavelength band black and white photographic exposure provided a better correlation to algal biomass than either red or infrared photographic exposure. Of all the biomass parameters tested, depth-integrated chlorophyll a concentration correlated best to remote sensing data. Laboratory-measured reflectance of selected algae indicate that different taxonomic classes of algae may be discriminated on the basis of their reflectance spectra.

  4. Effect of n-3 HUFA levels in rotifers and Artemia on growth and survival of larval black sea bream ( Sparus macrocephalus)

    NASA Astrophysics Data System (ADS)

    Liu, Jingke; Li, Kuiran; Huang, Bingxin; Chen, Xiaolin

    2004-12-01

    Requirement for dietary n-3 HUFA (n-3 highly unsaturated fatty acid) for growth and survival of black sea bream ( Sparus macrocephalus) larvae was studied using rotifers and Artemia at various levels of n-3 HUFA. Five treatments with rotifers and Artemia differing in n-3 HUFA were prepared by enriching them with various oil emulsions. Results indicated that dietary n-3 HUFA significantly influence fish n-3 HUFA levels and are essential for growth and survival of black sea bream larvae. The results also indicated that the incorporation of n-3HUFA TG (triacylglycerols) into tissues of larval black sea bream was more effective from natural fish oil in comparison with n-3 HUFA fatty acid ethyl esters from ethyl-esterified oil.

  5. The life-table demographic response of freshwater rotifer Brachionus calyciflorus to multi-metal (Cu, Zn, Cd, Cr, and Mn) mixture interaction.

    PubMed

    Xu, Xiao-Ping; Xi, Yi-Long; Huang, Lin; Xiang, Xian-Ling

    2014-08-01

    The effects of multi-metal mixtures on the life-table demography of rotifers are not well known. In this study, the freshwater rotifer Brachionus calyciflorus was exposed to mixture of Cu, Zn, Cd, Cr, and Mn, and the life-table demographic parameters including net reproductive rate, generation time, life expectancy at hatching, and intrinsic rate of population increase were calculated. The results showed that interactions between a given element concentration, except Mn, and the other four elements mixture concentration affected the intrinsic rate of population increase (p < 0.01). Interactions between Zn concentration, as well as Mn, and the other four elements mixture concentration affected the net reproductive rate and the life expectancy at hatching, respectively (p < 0.05). The variation of parameters with the rise of the other four elements mixture concentrations from 0 to high was mainly attributed to the difference of interaction among the five metals mixture with different ratio of concentrations.

  6. Algae control for hydrogeneration canals

    SciTech Connect

    Grahovac, P.

    1997-02-16

    The purpose of this Cooperative Research and Development Agreement (CRADA) was to assess and develop control practices for nuisance algae growth in power canal that delivers water to hydro-generation facilities. This growth results in expenditures related not only to lost generation but also labor and materials costs associated with implementing remediation procedures. On an industry-wide basis these costs associated with nuisance algal growth are estimated to be several million dollars per year.

  7. Parasites in algae mass culture

    PubMed Central

    Carney, Laura T.; Lane, Todd W.

    2014-01-01

    Parasites are now known to be ubiquitous across biological systems and can play an important role in modulating algal populations. However, there is a lack of extensive information on their role in artificial ecosystems such as algal production ponds and photobioreactors. Parasites have been implicated in the demise of algal blooms. Because individual mass culture systems often tend to be unialgal and a select few algal species are in wide scale application, there is an increased potential for parasites to have a devastating effect on commercial scale monoculture. As commercial algal production continues to expand with a widening variety of applications, including biofuel, food and pharmaceuticals, the parasites associated with algae will become of greater interest and potential economic impact. A number of important algal parasites have been identified in algal mass culture systems in the last few years and this number is sure to grow as the number of commercial algae ventures increases. Here, we review the research that has identified and characterized parasites infecting mass cultivated algae, the techniques being proposed and or developed to control them, and the potential impact of parasites on the future of the algal biomass industry. PMID:24936200

  8. Halogenated Compounds from Marine Algae

    PubMed Central

    Cabrita, Maria Teresa; Vale, Carlos; Rauter, Amélia Pilar

    2010-01-01

    Marine algae produce a cocktail of halogenated metabolites with potential commercial value. Structures exhibited by these compounds go from acyclic entities with a linear chain to complex polycyclic molecules. Their medical and pharmaceutical application has been investigated for a few decades, however other properties, such as antifouling, are not to be discarded. Many compounds were discovered in the last years, although the need for new drugs keeps this field open as many algal species are poorly screened. The ecological role of marine algal halogenated metabolites has somehow been overlooked. This new research field will provide valuable and novel insight into the marine ecosystem dynamics as well as a new approach to comprehending biodiversity. Furthermore, understanding interactions between halogenated compound production by algae and the environment, including anthropogenic or global climate changes, is a challenging target for the coming years. Research of halogenated metabolites has been more focused on macroalgae than on phytoplankton. However, phytoplankton could be a very promising material since it is the base of the marine food chain with quick adaptation to environmental changes, which undoubtedly has consequences on secondary metabolism. This paper reviews recent progress on this field and presents trends on the role of marine algae as producers of halogenated compounds. PMID:20948909

  9. Using population demographic parameters to assess impacts of two polybrominated diphenyl ethers (BDE-47, BDE-209) on the rotifer Brachionus plicatilis.

    PubMed

    Sha, Jingjing; Wang, You; Chen, Hongmei; Wang, Ming; Wang, Hong; Li, Xiaohong; Qi, Lei; Tang, Xuexi

    2015-09-01

    Polybrominated diphenyl ethers (PBDEs) are highly persistent anthropogenic contaminants found in the environment, posing a risk to aquatic ecosystems, whereas there is a lack of data concerning their impacts on marine invertebrates. The objective of this study was to assess the relative lethal and sublethal aquatic toxicity effects of two PBDEs, BDE-47 and BDE-209 congeners, on marine zooplankton rotifer Brachionus plicatilis associated with PBDE concentrations and time of exposure. Gas chromatography-mass spectrometry (GC-MS) analyses were performed to determine actual PBDE concentrations. Rotifer population demographic parameters from life tables, including age-specific survivorship (lx), age-specific fecundity (mx), net reproductive rate (R0), intrinsic rate of increase (rm), finite rate of increase (λ), life expectancy (E0) and generation time (T), were used as measures of treatment effects. Results from this study have revealed increasingly intense negative effects on many of the rotifer demographic parameters with elevated PBDE concentrations. The population growth curves of B. plicatilis showed almost no lag phase and reached peak abundances within 11 days, while B. plicatilis exposed to BDE-209 had a lag phase of about 5 days. In addition, increased PBDE levels reduced the population abundances and peak population densities of B. plicatilis. The two PBDEs have caused the carrying capacity (K) suppressed and the negative influence turned more serious as the concentration rose. Results also revealed that the time to reach growth curve inflection point (Tp) was shortened by PBDEs to different degrees. This study not only indicated that life table demography and population growth curve studies were two important aspects used to evaluate toxicant PBDE effects, but also compared the two PBDE disruptions to the population growth and reproduction of the rotifer.

  10. Continuity effects on rotifers and microcrustaceans caused by the construction of a downstream reservoir in a cascade series (Iguaçu River, Brazil).

    PubMed

    Serafim-Júnior, M; Lansac-Tôha, F A; Lopes, R M; Perbiche-Neves, G

    2016-06-01

    This study evaluated changes in the community of rotifers and microcrustaceans associated with the construction of a large and dendritic reservoir in Iguaçu River (Brazil), as the last reservoir of a sequence of five cascading systems. Differences were clear between pre-filling and post-filling phases for organisms and some of environmental variables. In the pre-filling phase, the community was more homogeneous along the downstream river gradient, and spatial compartmentalization in the new reservoir was common during the post-filling phase. From 140 identified taxa, 10 species occurred exclusively in the pre-filling phase and 32 in the post-filling phase. After completion of the fifth reservoir filling-up, opportunistic, pioneer and fast-developing species quickly dominated, and downstream of the fourth reservoir the pre-filling decreasing gradient of richness, diversity and evenness disappeared. Richness of rotifers and cladocerans, cladocerans diversity, and evenness of rotifers, cladocerans and copepods were generally higher in the post-filling phase. A non-metric multidimensional analysis based on a presence/absence matrix depicted a homogeneous and dense group of species associated to the pre-filling phase and a second, dispersed group related to the post-filling phase. Spearman correlations pointed out significant positive effects of transparency on rotifer species richness in the post-filling phase, and negative effects on the microcrustacean richness in the pre-filling phase. Dam construction caused disruption of the downstream lotic gradient along the series of dams, leading to the development of distinct species in lentic spatial compartments.

  11. Microplastic Size-Dependent Toxicity, Oxidative Stress Induction, and p-JNK and p-p38 Activation in the Monogonont Rotifer (Brachionus koreanus).

    PubMed

    Jeong, Chang-Bum; Won, Eun-Ji; Kang, Hye-Min; Lee, Min-Chul; Hwang, Dae-Sik; Hwang, Un-Ki; Zhou, Bingsheng; Souissi, Sami; Lee, Su-Jae; Lee, Jae-Seong

    2016-08-16

    In this study, we evaluated accumulation and adverse effects of ingestion of microplastics in the monogonont rotifer (Brachionus koreanus). The dependence of microplastic toxicity on particle size was investigated by measuring several in vivo end points and studying the ingestion and egestion using 0.05-, 0.5-, and 6-μm nonfunctionalized polystyrene microbeads. To identify the defense mechanisms activated in response to microplastic exposure, the activities of several antioxidant-related enzymes and the phosphorylation status of mitogen-activated protein kinases (MAPKs) were determined. Exposure to polystyrene microbeads of all sizes led to significant size-dependent effects, including reduced growth rate, reduced fecundity, decreased lifespan and longer reproduction time. Rotifers exposed to 6-μm fluorescently labeled microbeads exhibited almost no fluorescence after 24 h, while rotifers exposed to 0.05- and 0.5-μm fluorescently labeled microbeads displayed fluorescence until 48 h, suggesting that 6-μm microbeads are more effectively egested from B. koreanus than 0.05- or 0.5-μm microbeads. This observation provides a potential explanation for our findings that microbead toxicity was size-dependent and smaller microbeads were more toxic. In vitro tests revealed that antioxidant-related enzymes and MAPK signaling pathways were significantly activated in response to microplastic exposure in a size-dependent manner.

  12. Microplastic Size-Dependent Toxicity, Oxidative Stress Induction, and p-JNK and p-p38 Activation in the Monogonont Rotifer (Brachionus koreanus).

    PubMed

    Jeong, Chang-Bum; Won, Eun-Ji; Kang, Hye-Min; Lee, Min-Chul; Hwang, Dae-Sik; Hwang, Un-Ki; Zhou, Bingsheng; Souissi, Sami; Lee, Su-Jae; Lee, Jae-Seong

    2016-08-16

    In this study, we evaluated accumulation and adverse effects of ingestion of microplastics in the monogonont rotifer (Brachionus koreanus). The dependence of microplastic toxicity on particle size was investigated by measuring several in vivo end points and studying the ingestion and egestion using 0.05-, 0.5-, and 6-μm nonfunctionalized polystyrene microbeads. To identify the defense mechanisms activated in response to microplastic exposure, the activities of several antioxidant-related enzymes and the phosphorylation status of mitogen-activated protein kinases (MAPKs) were determined. Exposure to polystyrene microbeads of all sizes led to significant size-dependent effects, including reduced growth rate, reduced fecundity, decreased lifespan and longer reproduction time. Rotifers exposed to 6-μm fluorescently labeled microbeads exhibited almost no fluorescence after 24 h, while rotifers exposed to 0.05- and 0.5-μm fluorescently labeled microbeads displayed fluorescence until 48 h, suggesting that 6-μm microbeads are more effectively egested from B. koreanus than 0.05- or 0.5-μm microbeads. This observation provides a potential explanation for our findings that microbead toxicity was size-dependent and smaller microbeads were more toxic. In vitro tests revealed that antioxidant-related enzymes and MAPK signaling pathways were significantly activated in response to microplastic exposure in a size-dependent manner. PMID:27438693

  13. Early expansion and expression of the lipopolysaccharide (LPS)-induced TNF-α factor (LITAF) gene family in the LPS-exposed monogonont rotifer Brachionus koreanus.

    PubMed

    Jeong, Chang-Bum; Lee, Jeong-Hyeon; Lee, Jae-Seong; Rhee, Jae-Sung

    2015-10-01

    To date, a single lipopolysaccharide-induced TNF-α factor (LITAF) homologue, mediating the expression of inflammatory cytokines including TNF-α in terms of host defense was identified in vertebrates and most invertebrates such as insects, mollusks, and crustaceans. However, LITAF gene family members have recently been characterized in only two mollusks, Crassostrea gigas and Mytilus galloprovincialis. Although a large gene family expansion of LITAF homologues was observed in the nematode Caenorhabditis elegans, the amino acid sequences encoded by the C. elegans LITAF homologue have low similarities to other LITAF gene family members. In this study, three LITAF genes were identified in the monogonont rotifer Brachionus koreanus. In silico analyses of B. koreanus LITAF genes of conserved domains and phylogenetic relationships supported gene annotations that indicated that LITAF is involved in innate immunity in primitive rotifers. To examine transcriptional sensitivity of B. koreanus LITAF genes, the rotifers were exposed to different concentrations of lipopolysaccharide (LPS). Transcriptional levels of LITAF1 and LITAF2 gene were significantly upregulated dose- and time-dependently in response to LPS exposure for 24 h. LPS exposure induced glutathione (GSH) depletion and antioxidant enzyme activity levels for 24 h in B. koreanus. These results suggested that the B. koreanus LITAF gene family has potential sensitivities directly and/or indirectly to immune stimulator-triggered oxidative stress.

  14. Complete Genome Sequence of Endomicrobium proavitum, a Free-Living Relative of the Intracellular Symbionts of Termite Gut Flagellates (Phylum Elusimicrobia)

    PubMed Central

    Zheng, Hao

    2015-01-01

    We sequenced the complete genome of Endomicrobium proavitum strain Rsa215, the first isolate of the class Endomicrobia (phylum Elusimicrobia). It is the closest free-living relative of the endosymbionts of termite gut flagellates and thereby provides an excellent model for studying the evolutionary processes during the establishment of an intracellular symbiosis. PMID:26184928

  15. The soil flagellate Proleptomonas faecicola: cell organisation and phylogeny suggest that the only described free-living trypanosomatid is not a kinetoplastid but has cercomonad affinities.

    PubMed

    Vickerman, Keith; Le Ray, Dominique; Hoef-Emden, Kerstin; De Jonckheere, Johan

    2002-03-01

    The only putative free-living trypanosomatid is Proleptomonas faecicola described first by Woodcock in 1916 as a coprophilic flagellate with striking Leptomonas-like flagellar movement but lacking a kinetoplast. P faecicola was later identified by Sandon in 1927 as a widespread non-phagotrophic inhabitant of soils. No division stages were seen by either observer. An organism conforming to Woodcock's light microscope description has been isolated from tapwater and cultivated axenically in various serum-containing media. Division has been shown to occur in an aflagellate stage enclosed in a thin cyst wall. Electron microscopy of the flagellate stage reveals that, in addition to the long locomotory flagellum, a second non-motile flagellum is present attached to the body along its entire length. The flagellate's ultrastructure lacks all the major features of the Trypanosomatidae. The several mitochondria of Proleptomonas have tubular cristae and lie between intracytoplasmic microtubules originating as a loose cone associated with the flagellar basal bodies. This cytoskeleton is much reduced in the division cyst. A comparable Proleptomonas-like flagellate with similar division cysts has been observed in soil samples from farmland. Phylogenetic analysis based on SSU rRNA gene sequences suggests that the cultured organism identified here as Proleptomonas is unrelated to the Kinetoplastida and has affinities with the Phylum Cercozoa Cavalier-Smith, even though in morphology, life cycle and mode of feeding it bears little resemblance to any member of that diverse grouping. PMID:12022280

  16. Interventional procedure based on nanorobots propelled and steered by flagellated magnetotactic bacteria for direct targeting of tumors in the human body.

    PubMed

    Martel, Sylvain; Felfoul, Ouajdi; Mohammadi, Mahmood; Mathieu, Jean-Baptiste

    2008-01-01

    Flagellated bacteria used as bio-actuators may prove to be efficient propulsion mechanisms for future hybrid medical nanorobots when operating in the microvasculature. Here, we briefly describe a medical interventional procedure where flagellated bacteria and more specifically MC-1 Magnetotactic Bacteria (MTB) can be used to propel and steer micro-devices and nanorobots under computer control to reach remote locations in the human body. In particular, we show through experimental results the potential of using MTB-tagged robots to deliver therapeutic agents to tumors even the ones located in deep regions of the human body. We also show that such bacterial nanorobots can be tracked inside the human body for enhanced targeting under computer guidance using MRI as imaging modality. MTB can not only be guided and controlled directly towards a specific target, but we also show experimentally that these flagellated bacterial nanorobots can be propelled and steered in vivo deeply through the interstitial region of a tumor. The targeting efficacy is increased when combined with larger ferromagnetic micro-carriers being propelled by magnetic gradients generated by a MRI platform to carry and release nanorobots propelled by a single flagellated bacterium near the arteriocapillar entry. Based on the experimental data obtained and the experience gathered during several experiments conducted in vivo with this new approach, a general medical interventional procedure is briefly described here in a biomedical engineering context.

  17. A survey of flagellate diversity at four deep-sea hydrothermal vents in the Eastern Pacific Ocean using structural and molecular approaches.

    PubMed

    Atkins, M S; Teske, A P; Anderson, O R

    2000-01-01

    Eighteen strains of flagellated protists representing nine species were isolated and cultured from four deep-sea hydrothermal vents: Juan de Fuca Ridge (2,200 m), Guaymas Basin (2,000 m), 21 degrees N (2,550 m) and 9 degrees N (2,000 m). Light and electron microscopy were used to identify flagellates to genus and, when possible, species. The small subunit ribosomal RNA genes of each vent species and related strains from shallow-waters and the American Type Culture Collection were sequenced then used for comparative analysis with database sequences to place taxa in an rDNA tree. The hydrothermal vent flagellates belonged to six different taxonomic orders: the Ancyromonadida, Bicosoecida, Cercomonadida, Choanoflagellida, Chrysomonadida, and Kinetoplastida. Comparative analysis of vent isolate and database sequences resolved systematic placement of some well-known species with previously uncertain taxonomic affinities, such as Ancyromonas sigmoides, Caecitellus parvulus, and Massisteria marina. Many of these vent isolates are ubiquitous members of marine, freshwater, and terrestrial ecosystems worldwide, suggesting a global distribution of these flagellate species.

  18. Stochastic Forecasting of Algae Blooms in Lakes

    SciTech Connect

    Wang, Peng; Tartakovsky, Daniel M.; Tartakovsky, Alexandre M.

    2013-01-15

    We consider the development of harmful algae blooms (HABs) in a lake with uncertain nutrients inflow. Two general frameworks, Fokker-Planck equation and the PDF methods, are developed to quantify the resultant concentration uncertainty of various algae groups, via deriving a deterministic equation of their joint probability density function (PDF). A computational example is examined to study the evolution of cyanobacteria (the blue-green algae) and the impacts of initial concentration and inflow-outflow ratio.

  19. Flagellated Magnetotactic Bacteria as Controlled MRI-trackable Propulsion and Steering Systems for Medical Nanorobots Operating in the Human Microvasculature

    PubMed Central

    Martel, Sylvain; Mohammadi, Mahmood; Felfoul, Ouajdi; Lu, Zhao; Pouponneau, Pierre

    2009-01-01

    Although nanorobots may play critical roles for many applications in the human body such as targeting tumoral lesions for therapeutic purposes, miniaturization of the power source with an effective onboard controllable propulsion and steering system have prevented the implementation of such mobile robots. Here, we show that the flagellated nanomotors combined with the nanometer-sized magnetosomes of a single Magnetotactic Bacterium (MTB) can be used as an effective integrated propulsion and steering system for devices such as nanorobots designed for targeting locations only accessible through the smallest capillaries in humans while being visible for tracking and monitoring purposes using modern medical imaging modalities such as Magnetic Resonance Imaging (MRI). Through directional and magnetic field intensities, the displacement speeds, directions, and behaviors of swarms of these bacterial actuators can be controlled from an external computer. PMID:19890435

  20. Flagellated Magnetotactic Bacteria as Controlled MRI-trackable Propulsion and Steering Systems for Medical Nanorobots Operating in the Human Microvasculature.

    PubMed

    Martel, Sylvain; Mohammadi, Mahmood; Felfoul, Ouajdi; Lu, Zhao; Pouponneau, Pierre

    2009-04-01

    Although nanorobots may play critical roles for many applications in the human body such as targeting tumoral lesions for therapeutic purposes, miniaturization of the power source with an effective onboard controllable propulsion and steering system have prevented the implementation of such mobile robots. Here, we show that the flagellated nanomotors combined with the nanometer-sized magnetosomes of a single Magnetotactic Bacterium (MTB) can be used as an effective integrated propulsion and steering system for devices such as nanorobots designed for targeting locations only accessible through the smallest capillaries in humans while being visible for tracking and monitoring purposes using modern medical imaging modalities such as Magnetic Resonance Imaging (MRI). Through directional and magnetic field intensities, the displacement speeds, directions, and behaviors of swarms of these bacterial actuators can be controlled from an external computer.

  1. Rotifer rDNA-specific R9 retrotransposable elements generate an exceptionally long target site duplication upon insertion.

    PubMed

    Gladyshev, Eugene A; Arkhipova, Irina R

    2009-12-15

    Ribosomal DNA genes in many eukaryotes contain insertions of non-LTR retrotransposable elements belonging to the R2 clade. These elements persist in the host genomes by inserting site-specifically into multicopy target sites, thereby avoiding random disruption of single-copy host genes. Here we describe R9 retrotransposons from the R2 clade in the 28S RNA genes of bdelloid rotifers, small freshwater invertebrate animals best known for their long-term asexuality and for their ability to survive repeated cycles of desiccation and rehydration. While the structural organization of R9 elements is highly similar to that of other members of the R2 clade, they are characterized by two distinct features: site-specific insertion into a previously unreported target sequence within the 28S gene, and an unusually long target site duplication of 126 bp. We discuss the implications of these findings in the context of bdelloid genome organization and the mechanisms of target-primed reverse transcription.

  2. Morphological alterations in the freshwater rotifer Brachionus calyciflorus Pallas 1766 (Rotifera: Monogononta) caused by vinclozolin chronic exposure.

    PubMed

    Alvarado-Flores, Jesús; Rico-Martínez, Roberto; Adabache-Ortíz, Araceli; Silva-Briano, Marcelo

    2015-05-01

    Vinclozolin (VZ) is a dicarboximide fungicide widely used on fruits, vegetables and wines, effective against fungi plagues. In this study we characterized the effects of VZ using a 4-day reproductive chronic assay with the freshwater rotifer Brachionus calyciflorus. The assay included observations of several features of asexual and sexual reproduction. Our results indicate that VZ: (a) increased asexual and sexual reproduction, (b) caused severe abnormality in females and (c) these abnormalities were inherited by sexual and asexual reproduction. At 1.2 mg/L three abnormal females were found out of 457 total females (0.66 %). This low percentage is consistent and reproducible according to further analysis, where we increased the number of replicates and total females exposed to 1.2 mg/L of VZ, and found 18 abnormal females out of 2868 total females (0.63 % abnormality). Interestingly, abnormal females found at 5.6 mg/L VZ exposure, were able to show mating behavior. Our results suggest that VZ behaves as a strong endocrine disruptor whose effects show the characteristic inverted-U-shape exposure concentration response curve regarding the intrinsic population increase and the percentage of abnormalities as endpoints.

  3. Sublethal gamma irradiation affects reproductive impairment and elevates antioxidant enzyme and DNA repair activities in the monogonont rotifer Brachionus koreanus.

    PubMed

    Han, Jeonghoon; Won, Eun-Ji; Kim, Il-Chan; Yim, Joung Han; Lee, Su-Jae; Lee, Jae-Seong

    2014-10-01

    To examine the effects of gamma radiation on marine organisms, we irradiated several doses of gamma ray to the microzooplankton Brachionus koreanus, and measured in vivo and in vitro endpoints including the survival rate, lifespan, fecundity, population growth, gamma ray-induced oxidative stress, and modulated patterns of enzyme activities and gene expressions after DNA damage. After gamma radiation, no individuals showed any mortality within 96 h even at a high intensity (1200 Gy). However, a reduced fecundity (e.g. cumulated number of offspring) of B. koreanus at over 150 Gy was observed along with a slight decrease in lifespan. At 150 Gy and 200 Gy, the reduced fecundity of the rotifers led to a significant decrease in population growth, although in the second generation the population growth pattern was not affected even at 200 Gy when compared to the control group. At sub-lethal doses, reactive oxygen species (ROS) levels dose-dependently increased with GST enzyme activity. In addition, up-regulations of the antioxidant and chaperoning genes in response to gamma radiation were able to recover cellular damages, and life table parameters were significantly influenced, particularly with regard to fecundity. DNA repair-associated genes showed significantly up-regulated expression patterns in response to sublethal doses (150 and 200 Gy), as shown in the expression of the gamma-irradiated B. koreanus p53 gene, suggesting that these sublethal doses were not significantly fatal to B. koreanus but induced DNA damages leading to a decrease of the population size.

  4. Cultivation of macroscopic marine algae

    SciTech Connect

    Ryther, J.H.

    1982-11-01

    The red alga Gracilaria tikvahiae may be grown outdoors year-round in central Florida with yields averaging 35.5 g dry wt/m/sup 2/.day, greater than the most productive terrestrial plants. This occurs only when the plants are in a suspended culture, with vigorous aeration and an exchange of 25 or more culture volumes of enriched seawater per day, which is not cost-effective. A culture system was designed in which Gracilaria, stocked at a density of 2 kg wet wt/m/sup 2/, grows to double its biomass in one to two weeks; it is then harvested to its starting density, and anaerobically digested to methane. The biomass is soaked for 6 hours in the digester residue, storing enough nutrients for two weeks' growth in unenriched seawater. The methane is combusted for energy and the waste gas is fed to the culture to provide mixing and CO/sub 2/, eliminating the need for aeration and seawater exchange. The green alga Ulva lactuca, unlike Gracilaria, uses bicarbonate as a photosynthesis carbon source, and can grow at high pH, with little or no free CO/sub 2/. It can therefore produce higher yields than Gracilaria in low water exchange conditions. It is also more efficiently converted to methane than is Gracilaria, but cannot tolerate Florida's summer temperatures so cannot be grown year-round. Attempts are being made to locate or produce a high-temperature tolerant strain.

  5. Hydrogen metabolism of photosynthetic bacteria and algae

    SciTech Connect

    Kumazawa, S.; Mitsui, A.

    1982-01-01

    The metabolism, metabolic pathways and biochemistry of hydrogen in photosynthetic bacteria and algae are reviewed. Detailed information on the occurrence and measurement of hydrogenase activity is presented. Hydrogen production rates for different species of algae and bacteria are presented. 173 references, 1 figure, 7 tables.

  6. SSMILes: Measuring the Nutrient Tolerance of Algae.

    ERIC Educational Resources Information Center

    Hedgepeth, David J.

    1995-01-01

    Presents an activity integrating mathematics and science intended to introduce students to the use of metric measurement of mass as a way to increase the meaningfulness of observations about variables in life sciences. Involves measuring the nutrient tolerance of algae. Contains a reproducible algae nutrient graph. (Author/MKR)

  7. Take a Dip! Culturing Algae Is Easy.

    ERIC Educational Resources Information Center

    James, Daniel E.

    1983-01-01

    Describes laboratory activities using algae as the organisms of choice. These include examination of typical algal cells, demonstration of alternation of generations, sexual reproduction in Oedogonium, demonstration of phototaxis, effect of nitrate concentration on Ankistrodesmus, and study of competition between two algae in the same environment.…

  8. Nutritional And Taste Characteristics Of Algae

    NASA Technical Reports Server (NTRS)

    Karel, M.; Nakhost, Z.

    1992-01-01

    Report describes investigation of chemical composition of blue-green algae Synechococcus 6311, as well as preparation of protein isolate from green alga Scenedesmus obliquus and incorporation into variety of food products evaluated for taste. Part of program to investigate growth of microalgae aboard spacecraft for use as food.

  9. Effect of Dead Algae on Soil Permeability

    SciTech Connect

    Harvey, R.S.

    2003-02-21

    Since existing basins support heavy growths of unicellular green algae which may be killed by temperature variation or by inadvertent pH changes in waste and then deposited on the basin floor, information on the effects of dead algae on soil permeability was needed. This study was designed to show the effects of successive algal kills on the permeability of laboratory soil columns.

  10. Eco-physiological adaptation shapes the response of calcifying algae to nutrient limitation

    NASA Astrophysics Data System (ADS)

    Šupraha, Luka; Gerecht, Andrea C.; Probert, Ian; Henderiks, Jorijntje

    2015-11-01

    The steady increase in global ocean temperature will most likely lead to nutrient limitation in the photic zone. This will impact the physiology of marine algae, including the globally important calcifying coccolithophores. Understanding their adaptive patterns is essential for modelling carbon production in a low-nutrient ocean. We investigated the physiology of Helicosphaera carteri, a representative of the abundant but under-investigated flagellated functional group of coccolithophores. Two strains isolated from contrasting nutrient regimes (South Atlantic and Mediterranean Sea) were grown in phosphorus-replete and phosphorus-limited batch cultures. While growing exponentially in a phosphorus-replete medium, the Mediterranean strain exhibited on average 24% lower growth rate, 36% larger coccosphere volume and 21% lower particulate inorganic carbon (PIC) production than the Atlantic strain. Under phosphorus limitation, the same strain was capable of reaching a 2.6 times higher cell density than the Atlantic strain due to lower phosphorus requirements. These results suggest that local physiological adaptation can define the performance of this species under nutrient limitation.

  11. Eco-physiological adaptation shapes the response of calcifying algae to nutrient limitation

    PubMed Central

    Šupraha, Luka; Gerecht, Andrea C.; Probert, Ian; Henderiks, Jorijntje

    2015-01-01

    The steady increase in global ocean temperature will most likely lead to nutrient limitation in the photic zone. This will impact the physiology of marine algae, including the globally important calcifying coccolithophores. Understanding their adaptive patterns is essential for modelling carbon production in a low-nutrient ocean. We investigated the physiology of Helicosphaera carteri, a representative of the abundant but under-investigated flagellated functional group of coccolithophores. Two strains isolated from contrasting nutrient regimes (South Atlantic and Mediterranean Sea) were grown in phosphorus-replete and phosphorus-limited batch cultures. While growing exponentially in a phosphorus-replete medium, the Mediterranean strain exhibited on average 24% lower growth rate, 36% larger coccosphere volume and 21% lower particulate inorganic carbon (PIC) production than the Atlantic strain. Under phosphorus limitation, the same strain was capable of reaching a 2.6 times higher cell density than the Atlantic strain due to lower phosphorus requirements. These results suggest that local physiological adaptation can define the performance of this species under nutrient limitation. PMID:26560531

  12. Eco-physiological adaptation shapes the response of calcifying algae to nutrient limitation.

    PubMed

    Šupraha, Luka; Gerecht, Andrea C; Probert, Ian; Henderiks, Jorijntje

    2015-11-12

    The steady increase in global ocean temperature will most likely lead to nutrient limitation in the photic zone. This will impact the physiology of marine algae, including the globally important calcifying coccolithophores. Understanding their adaptive patterns is essential for modelling carbon production in a low-nutrient ocean. We investigated the physiology of Helicosphaera carteri, a representative of the abundant but under-investigated flagellated functional group of coccolithophores. Two strains isolated from contrasting nutrient regimes (South Atlantic and Mediterranean Sea) were grown in phosphorus-replete and phosphorus-limited batch cultures. While growing exponentially in a phosphorus-replete medium, the Mediterranean strain exhibited on average 24% lower growth rate, 36% larger coccosphere volume and 21% lower particulate inorganic carbon (PIC) production than the Atlantic strain. Under phosphorus limitation, the same strain was capable of reaching a 2.6 times higher cell density than the Atlantic strain due to lower phosphorus requirements. These results suggest that local physiological adaptation can define the performance of this species under nutrient limitation.

  13. Antarctic sea ice thickness affects algae populations

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2013-01-01

    In the waters off Antarctica, algae grow and live in the sea ice that surrounds the southern continent—a floating habitat sure to change as the planet warms. As with most aquatic ecosystems, microscopic algae form the base of the Southern Ocean food web. Distinct algae populations reside in the sea ice surface layers, on the ice's underside, and within the floating ice itself. The algae that reside on the floating ice's underside are particularly important for the region's krill population, while those on the interior or surface layers are less accessible. Understanding how changing sea ice properties will affect the regional biology, then, depends on understanding how algae populations interact with the ice.

  14. The ice nucleation activity of extremophilic algae.

    PubMed

    Kviderova, Jana; Hajek, Josef; Worland, Roger M

    2013-01-01

    Differences in the level of cold acclimation and cryoprotection estimated as ice nucleation activity in snow algae (Chlamydomonas cf. nivalis and Chloromonas nivalis), lichen symbiotic algae (Trebouxia asymmetrica, Trebouxia erici and Trebouxia glomerata), and a mesophilic strain (Chlamydomonas reinhardti) were evaluated. Ice nucleation activity was measured using the freezing droplet method. Measurements were performed using suspensions of cells of A750 (absorbance at 750 nm) ~ 1, 0.1, 0.01 and 0.001 dilutions for each strain. The algae had lower ice nucleation activity, with the exception of Chloromonas nivalis contaminated by bacteria. The supercooling points of the snow algae were higher than those of lichen photobionts. The supercooling points of both, mesophilic and snow Chlamydomonas strains were similar. The lower freezing temperatures of the lichen algae may reflect either the more extreme and more variable environmental conditions of the original localities or the different cellular structure of the strains examined.

  15. Composting of waste algae: a review.

    PubMed

    Han, Wei; Clarke, William; Pratt, Steven

    2014-07-01

    Although composting has been successfully used at pilot scale to manage waste algae removed from eutrophied water environments and the compost product applied as a fertiliser, clear guidelines are not available for full scale algae composting. The review reports on the application of composting to stabilize waste algae, which to date has mainly been macro-algae, and identifies the peculiarities of algae as a composting feedstock, these being: relatively low carbon to nitrogen (C/N) ratio, which can result in nitrogen loss as NH3 and even N2O; high moisture content and low porosity, which together make aeration challenging; potentially high salinity, which can have adverse consequence for composting; and potentially have high metals and toxin content, which can affect application of the product as a fertiliser. To overcome the challenges that these peculiarities impose co-compost materials can be employed.

  16. Flocculation of model algae under shear.

    SciTech Connect

    Pierce, Flint; Lechman, Jeremy B.

    2010-11-01

    We present results of molecular dynamics simulations of the flocculation of model algae particles under shear. We study the evolution of the cluster size distribution as well as the steady-state distribution as a function of shear rates and algae interaction parameters. Algal interactions are modeled through a DLVO-type potential, a combination of a HS colloid potential (Everaers) and a yukawa/colloid electrostatic potential. The effect of hydrodynamic interactions on aggregation is explored. Cluster strucuture is determined from the algae-algae radial distribution function as well as the structure factor. DLVO parameters including size, salt concentration, surface potential, initial volume fraction, etc. are varied to model different species of algae under a variety of environmental conditions.

  17. Algae inhibition experiment and load characteristics of the algae solution

    NASA Astrophysics Data System (ADS)

    Xiong, L.; Gao, J. X.; Zhang, Y. X.; Yang, Z. K.; Zhang, D. Q.; He, W.

    2016-08-01

    It is necessary to inhibit microbial growth in an industrial cooling water system. This paper has developed a Monopolar/Bipolar polarity high voltage pulser with load adaptability for an algal experimental study. The load characteristics of the Chlorella pyrenoidosa solution were examined, and it was found that the solution load is resistive. The resistance is related to the plate area, concentration, and temperature of the solution. Furthermore, the pulser's treatment actually inhibits the algae cell growth. This article also explores the influence of various parameters of electric pulses on the algal effect. After the experiment, the optimum pulse parameters were determined to be an electric field intensity of 750 V/cm, a pulse width per second of 120μs, and monopolar polarity.

  18. Microbodies of the alga Chara.

    PubMed

    Stabenau, Helmut; Säftel, Werner; Winkler, Uwe

    2003-05-01

    Chara fragilis possesses microbodies with a remarkably large size of up to 2 micro m in diameter. Many of the organelles contain huge nucleoids of amorphous material or paracrystalline inclusions. After isolation of the organelles by gradient centrifugation the specific density of the microbodies was determined to be 1.25 g cm-3. Catalase, glycolate oxidase and hydroxypyruvate reductase as well as enzymes of the fatty acid beta-oxidation pathway were demonstrated to be constituents of the microbodies in Chara indicating that they are similar to those in green leaves. The data obtained are in agreement with the view that the Charophyceae and especially the algae in the subgroup of Charales are very closely related to the land plants.

  19. Algae biodiesel - a feasibility report

    PubMed Central

    2012-01-01

    Background Algae biofuels have been studied numerous times including the Aquatic Species program in 1978 in the U.S., smaller laboratory research projects and private programs. Results Using Molina Grima 2003 and Department of Energy figures, captial costs and operating costs of the closed systems and open systems were estimated. Cost per gallon of conservative estimates yielded $1,292.05 and $114.94 for closed and open ponds respectively. Contingency scenarios were generated in which cost per gallon of closed system biofuels would reach $17.54 under the generous conditions of 60% yield, 50% reduction in the capital costs and 50% hexane recovery. Price per gallon of open system produced fuel could reach $1.94 under generous assumptions of 30% yield and $0.2/kg CO2. Conclusions Current subsidies could allow biodiesel to be produced economically under the generous conditions specified by the model. PMID:22540986

  20. Effects of two polybrominated diphenyl ethers (BDE-47, BDE-209) on the swimming behavior, population growth and reproduction of the rotifer Brachionus plicatilis.

    PubMed

    Sha, Jingjing; Wang, You; Lv, Jianxia; Wang, Hong; Chen, Hongmei; Qi, Leilei; Tang, Xuexi

    2015-02-01

    Polybrominated diphenyl ethers (PBDEs) are new kinds of persistent organic pollutants (POPs) and their potential threats to the equilibrium and sustainability of marine ecosystems have raised worldwide concerns. Here, two kinds of PBDEs, tetra-BDE (BDE-47) and deca-BDE (BDE-209) were applied, and their toxic effects on the swimming behavior, population growth and reproduction of Brachionus plicatilis were investigated. The results showed that: (1) The actual concentrations of BDE-47 and -209 in the seawater phase measured by GC-MS (Gas Chromatography-Mass Spectrometer) were much lower than their nominal concentrations. (2) In accordance with the 24-hr acute tests, BDE-209 did not show any obvious swimming inhibition to rotifers, but a good correlation did exist between the swimming inhibition rate and BDE-47 concentration suggesting that BDE-47 is more toxic than BDE-209. (3) Both BDE-47 and -209 had a significant influence on the population growth and reproduction parameters of B. plicatilis including the population growth rate, the ratio of ovigerous females/non-ovigerous females (OF/NOF), the ratio of mictic females/amictic females (MF/AF), resting egg production and the mictic rate, which indicate that these parameters in B. plicatilis population were suitable for monitoring and assessing PBDEs. Our results suggest that BDE-47 and -209 are not acute lethal toxicants and may pose a low risk to marine rotifers at environmental concentrations for short-term exposure. They also accumulate differently into rotifers. Further research data are needed to understand the mechanisms responsible for the effects caused by PBDEs and to assess their risks accurately.

  1. Identification of three doublesex genes in the monogonont rotifer Brachionus koreanus and their transcriptional responses to environmental stressor-triggered population growth retardation.

    PubMed

    Kim, Bo-Mi; Jeong, Chang-Bum; Kim, Il-Chan; Yim, Joung Han; Lee, Yong Sung; Rhee, Jae-Sung; Lee, Jae-Seong

    2014-08-01

    Doublesex and Mab-3-related transcription factor (Dmrt) gene family members have rarely been identified or characterized in aquatic invertebrates. In this study, we identified and characterized three DMdomain-containing genes - Dmrt11E, Dmrt93B, and Dmrt99B - in the monogonont rotifer, Brachionus koreanus. DMdomains of the proteins encoded by the B.koreanus Dmrt (Bk-Dmrt) genes had high similarities to DM domains of other invertebrate species. To understand the potential effects of environmental stressors on the transcriptional expression of Dmrt genes in rotifers, we exposed B.koreanus to a wide range of UV-B radiation and different concentrations of benzo[a]pyrene (B[a]P) over different time courses. Transcript levels of all Bk-Dmrt genes decreased significantly in response to relatively high doses of UV-B irradiation, and were also downregulated in response to exposure to UV-B radiation over time. Transcript levels of all Bk-Dmrt genes were downregulated in response to B[a]P exposure for 24h. This decrease in expression of all Bk-Dmrt genes was concomitant with the growth retardation induced by UV-B and B[a]P exposure. We concluded that both environmental stressors have detrimental effects on transcriptional regulation of all Bk-Dmrt genes, especially relatively high doses of these stressors, leading to growth retardation. However, further studies are required to better understand the potential role of Dmrt genes in environmental stressor-triggered growth retardation in the rotifer B.koreanus.

  2. Formosa haliotis sp. nov., a brown-alga-degrading bacterium isolated from the gut of the abalone Haliotis gigantea.

    PubMed

    Tanaka, Reiji; Cleenwerck, Ilse; Mizutani, Yukino; Iehata, Shunpei; Shibata, Toshiyuki; Miyake, Hideo; Mori, Tetsushi; Tamaru, Yutaka; Ueda, Mitsuyoshi; Bossier, Peter; Vandamme, Peter

    2015-12-01

    Four brown-alga-degrading, Gram-stain-negative, aerobic, non-flagellated, gliding and rod-shaped bacteria, designated LMG 28520T, LMG 28521, LMG 28522 and LMG 28523, were isolated from the gut of the abalone Haliotis gigantea obtained in Japan. The four isolates had identical random amplified polymorphic DNA patterns and grew optimally at 25 °C, at pH 6.0-9.0 and in the presence of 1.0-4.0 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences placed the isolates in the genus Formosa with Formosa algae and Formosa arctica as closest neighbours. LMG 28520T and LMG 28522 showed 100 % DNA-DNA relatedness to each other, 16-17 % towards F. algae LMG 28216T and 17-20 % towards F. arctica LMG 28318T; they could be differentiated phenotypically from these established species. The predominant fatty acids of isolates LMG 28520T and LMG 28522 were summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c), iso-C15 : 1 G and iso-C15 : 0. Isolate LMG 28520T contained menaquinone-6 (MK-6) as the major respiratory quinone and phosphatidylethanolamine, two unknown aminolipids and an unknown lipid as the major polar lipids. The DNA G+C content was 34.4 mol% for LMG 28520T and 35.5 mol% for LMG 28522. On the basis of their phylogenetic and genetic distinctiveness, and differential phenotypic properties, the four isolates are considered to represent a novel species of the genus Formosa, for which the name Formosa haliotis sp. nov. is proposed. The type strain is LMG 28520T ( = NBRC 111189T). PMID:26354496

  3. DGDG and Glycolipids in Plants and Algae.

    PubMed

    Kalisch, Barbara; Dörmann, Peter; Hölzl, Georg

    2016-01-01

    Photosynthetic organelles in plants and algae are characterized by the high abundance of glycolipids, including the galactolipids mono- and digalactosyldiacylglycerol (MGDG, DGDG) and the sulfolipid sulfoquinovosyldiacylglycerol (SQDG). Glycolipids are crucial to maintain an optimal efficiency of photosynthesis. During phosphate limitation, the amounts of DGDG and SQDG increase in the plastids of plants, and DGDG is exported to extraplastidial membranes to replace phospholipids. Algae often use betaine lipids as surrogate for phospholipids. Glucuronosyldiacylglycerol (GlcADG) is a further glycolipid that accumulates under phosphate deprived conditions. In contrast to plants, a number of eukaryotic algae contain very long chain polyunsaturated fatty acids of 20 or more carbon atoms in their glycolipids. The pathways and genes for galactolipid and sulfolipid synthesis are largely conserved between plants, Chlorophyta, Rhodophyta and algae with complex plastids derived from secondary or tertiary endosymbiosis. However, the relative contribution of the endoplasmic reticulum- and plastid-derived lipid pathways for glycolipid synthesis varies between plants and algae. The genes for glycolipid synthesis encode precursor proteins imported into the photosynthetic organelles. While most eukaryotic algae contain the plant-like galactolipid (MGD1, DGD1) and sulfolipid (SQD1, SQD2) synthases, the red alga Cyanidioschyzon harbors a cyanobacterium-type DGDG synthase (DgdA), and the amoeba Paulinella, derived from a more recent endosymbiosis event, contains cyanobacterium-type enzymes for MGDG and DGDG synthesis (MgdA, MgdE, DgdA). PMID:27023231

  4. Algae Biofuel in the Nigerian Energy Context

    NASA Astrophysics Data System (ADS)

    Elegbede, Isa; Guerrero, Cinthya

    2016-05-01

    The issue of energy consumption is one of the issues that have significantly become recognized as an important topic of global discourse. Fossil fuels production reportedly experiencing a gradual depletion in the oil-producing nations of the world. Most studies have relatively focused on biofuel development and adoption, however, the awareness of a prospect in the commercial cultivation of algae having potential to create economic boost in Nigeria, inspired this research. This study aims at exploring the potential of the commercialization of a different but commonly found organism, algae, in Nigeria. Here, parameters such as; water quality, light, carbon, average temperature required for the growth of algae, and additional beneficial nutrients found in algae were analysed. A comparative cum qualitative review of analysis was used as the study made use of empirical findings on the work as well as the author's deductions. The research explored the cultivation of algae with the two major seasonal differences (i.e. rainy and dry) in Nigeria as a backdrop. The results indicated that there was no significant difference in the contribution of algae and other sources of biofuels as a necessity for bioenergy in Nigeria. However, for an effective sustainability of this prospect, adequate measures need to be put in place in form of funding, provision of an economically-enabling environment for the cultivation process as well as proper healthcare service in the face of possible health hazard from technological processes. Further studies can seek to expand on the potential of cultivating algae in the Harmattan season.

  5. DGDG and Glycolipids in Plants and Algae.

    PubMed

    Kalisch, Barbara; Dörmann, Peter; Hölzl, Georg

    2016-01-01

    Photosynthetic organelles in plants and algae are characterized by the high abundance of glycolipids, including the galactolipids mono- and digalactosyldiacylglycerol (MGDG, DGDG) and the sulfolipid sulfoquinovosyldiacylglycerol (SQDG). Glycolipids are crucial to maintain an optimal efficiency of photosynthesis. During phosphate limitation, the amounts of DGDG and SQDG increase in the plastids of plants, and DGDG is exported to extraplastidial membranes to replace phospholipids. Algae often use betaine lipids as surrogate for phospholipids. Glucuronosyldiacylglycerol (GlcADG) is a further glycolipid that accumulates under phosphate deprived conditions. In contrast to plants, a number of eukaryotic algae contain very long chain polyunsaturated fatty acids of 20 or more carbon atoms in their glycolipids. The pathways and genes for galactolipid and sulfolipid synthesis are largely conserved between plants, Chlorophyta, Rhodophyta and algae with complex plastids derived from secondary or tertiary endosymbiosis. However, the relative contribution of the endoplasmic reticulum- and plastid-derived lipid pathways for glycolipid synthesis varies between plants and algae. The genes for glycolipid synthesis encode precursor proteins imported into the photosynthetic organelles. While most eukaryotic algae contain the plant-like galactolipid (MGD1, DGD1) and sulfolipid (SQD1, SQD2) synthases, the red alga Cyanidioschyzon harbors a cyanobacterium-type DGDG synthase (DgdA), and the amoeba Paulinella, derived from a more recent endosymbiosis event, contains cyanobacterium-type enzymes for MGDG and DGDG synthesis (MgdA, MgdE, DgdA).

  6. The amoeba-to-flagellate transformation test is not reliable for the diagnosis of the genus Naegleria. Description of three new Naegleria spp.

    PubMed

    De Jonckheere, J F; Brown, S; Dobson, P J; Robinson, B S; Pernin, P

    2001-07-01

    Trophozoites of several isolates from one location in Australia have failed consistently to transform into flagellates, although they display all other characteristics of the genus Naegleria. When changing the standard transformation test, flagellates were produced. In phylogenetic trees derived from partial small subunit ribosomal DNA (SSUrDNA) sequences, one of these strains branches close to a cluster comprising N. clarki, N. australiensis, N. italica and N. jadini. It is proposed that these Australian isolates represent a new species, named N. fultoni (strain NG885). Failing to form flagellates since their isolation, even when different transformation procedures are used, are two Naegleria strains from Chile and Indonesia. In SSUrDNA-based phylogenetic trees the Chilean strain clusters with N. pussardi and the Indonesian strain clusters with N. galeacystis, but the degree of sequence difference from these described species (3.5% and 2.2%, respectively) is sufficient to propose that both of the strains represent new species, named N. chilensis (strain NG946) and N. indonesiensis (strain NG945), respectively. The close relationships between each of the new species and the Naegleria species with which they cluster in SSUrDNA-based trees were confirmed by ribosomal internal transcribed spacer region (ITS) sequence comparisons. In France, several non-flagellating N. fowleri strains were isolated from one location. ITS rDNA sequence comparisons indicated that they correspond to a 'type' of N. fowleri found in both Europe and the USA. A redefinition of the genus Naegleria is proposed as a consequence of these and previous findings.

  7. Errors When Extracting Oil from Algae

    NASA Astrophysics Data System (ADS)

    Murphy, E.; Treat, R.; Ichiuji, T.

    2014-12-01

    Oil is in popular demand, but the worldwide amount of oil is decreasing and prices for it are steadily increasing. Leading scientists have been working to find a solution of attaining oil in an economically and environmentally friendly way. Researchers at the U.S. Department of Energy's Pacific Northwest National Laboratory (PNNL) have determined that "a small mixture of algae and water can be turned into crude oil in less than an hour" (Sheehan, Duhahay, Benemann, Poessler). There are various ways of growing the algae, such as closed loop and open loop methods, as well as processes of extracting oil, such as hydrothermal liquefaction and the hexane-solvent method. Our objective was to grow the algae (C. reinhardtii) and extract oil from it using NaOH and HCl, because we had easy access to those specific chemicals. After two trials of attempted algae growth, we discovered that a bacteria was killing off the algae. This led us to further contemplation on how this dead algae and bacteria are affecting our environment, and the organisms within it. Eutrophication occurs when excess nutrients stimulate rapid growth of algae in an aquatic environment. This can clog waterways and create algal blooms in blue-green algae, as well as neurotoxic red tide phytoplankton. These microscopic algae die upon consumption of the nutrients in water and are degraded by bacteria. The bacteria respires and creates an acidic environment with the spontaneous conversion of carbon dioxide to carbonic acid in water. This process of degradation is exactly what occurred in our 250 mL flask. When the phytoplankton attacked our algae, it created a hypoxic environment, which eliminated any remaining amounts of oxygen, carbon dioxide, and nutrients in the water, resulting in a miniature dead zone. These dead zones can occur almost anywhere where there are algae and bacteria, such as the ocean, and make it extremely difficult for any organism to survive. This experiment helped us realize the

  8. Method and apparatus for processing algae

    SciTech Connect

    Chew, Geoffrey; Reich, Alton J.; Dykes, Jr., H. Waite; Di Salvo, Roberto

    2012-07-03

    Methods and apparatus for processing algae are described in which a hydrophilic ionic liquid is used to lyse algae cells. The lysate separates into at least two layers including a lipid-containing hydrophobic layer and an ionic liquid-containing hydrophilic layer. A salt or salt solution may be used to remove water from the ionic liquid-containing layer before the ionic liquid is reused. The used salt may also be dried and/or concentrated and reused. The method can operate at relatively low lysis, processing, and recycling temperatures, which minimizes the environmental impact of algae processing while providing reusable biofuels and other useful products.

  9. Symbionts of the gut flagellate Staurojoenina sp. from Neotermes cubanus represent a novel, termite-associated lineage of Bacteroidales: description of 'Candidatus Vestibaculum illigatum'.

    PubMed

    Stingl, Ulrich; Maass, Annelie; Radek, Renate; Brune, Andreas

    2004-07-01

    The symbioses between cellulose-degrading flagellates and bacteria are one of the most fascinating phenomena in the complex micro-ecosystem found in the hindgut of lower termites. However, little is known about the identity of the symbionts. One example is the epibiotic bacteria colonizing the surface of hypermastigote protists of the genus Staurojoenina. By using scanning electron microscopy, it was shown that the whole surface of Staurojoenina sp. from the termite Neotermes cubanus is densely covered with long rod-shaped bacteria of uniform size and morphology. PCR amplification of 16S rRNA genes from isolated protozoa and subsequent cloning yielded a uniform collection of clones with virtually identical sequences. Phylogenetic analysis placed them as a new lineage among the Bacteroidales, only distantly related to other uncultivated bacteria in the hindgut of other termites, including an epibiont of the flagellate Mixotricha paradoxa. The closest cultivated relative was Tannerella forsythensis (<85 % sequence identity). Fluorescence in situ hybridization with a newly designed clone-specific oligonucleotide probe confirmed that these sequences belong to the rod-shaped epibionts of Staurojoenina sp. Transmission electron microscopy confirmed the presence of a Gram-negative cell wall and revealed special attachment sites for the symbionts on the cell envelope of the flagellate host. Based on the isolated phylogenetic position and the specific association with the surface of Staurojoenina sp., we propose to classify this new taxon of Bacteroidales under the provisional name 'Candidatus Vestibaculum illigatum'.

  10. 21 CFR 73.275 - Dried algae meal.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Dried algae meal. 73.275 Section 73.275 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.275 Dried algae meal. (a) Identity. The color additive dried algae meal is a dried mixture of algae cells (genus Spongiococcum, separated from its culture...

  11. 21 CFR 73.275 - Dried algae meal.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Dried algae meal. 73.275 Section 73.275 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.275 Dried algae meal. (a) Identity. The color additive dried algae meal is a dried mixture of algae cells (genus Spongiococcum, separated from its culture...

  12. 21 CFR 73.275 - Dried algae meal.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Dried algae meal. 73.275 Section 73.275 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.275 Dried algae meal. (a) Identity. The color additive dried algae meal is a dried mixture of algae cells (genus Spongiococcum, separated from its culture...

  13. 21 CFR 73.275 - Dried algae meal.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Dried algae meal. 73.275 Section 73.275 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.275 Dried algae meal. (a) Identity. The color additive dried algae meal is a dried mixture of algae cells (genus Spongiococcum, separated from its culture...

  14. 21 CFR 73.275 - Dried algae meal.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Dried algae meal. 73.275 Section 73.275 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.275 Dried algae meal. (a) Identity. The color additive dried algae meal is a dried mixture of algae cells (genus Spongiococcum, separated from its culture...

  15. Biogeography of Heterotrophic Flagellate Populations Indicates the Presence of Generalist and Specialist Taxa in the Arctic Ocean

    PubMed Central

    Thaler, Mary

    2015-01-01

    Heterotrophic marine flagellates (HF) are ubiquitous in the world's oceans and represented in nearly all branches of the domain Eukaryota. However, the factors determining distributions of major taxonomic groups are poorly known. The Arctic Ocean is a good model environment for examining the distribution of functionally similar but phylogenetically diverse HF because the physical oceanography and annual ice cycles result in distinct environments that could select for microbial communities or favor specific taxa. We reanalyzed new and previously published high-throughput sequencing data from multiple studies in the Arctic Ocean to identify broad patterns in the distribution of individual taxa. HF accounted for fewer than 2% to over one-half of the reads from the water column and for up to 60% of reads from ice, which was dominated by Cryothecomonas. In the water column, many HF phylotypes belonging to Telonemia and Picozoa, uncultured marine stramenopiles (MAST), and choanoflagellates were geographically widely distributed. However, for two groups in particular, Telonemia and Cryothecomonas, some species level taxa showed more restricted distributions. For example, several phylotypes of Telonemia favored open waters with lower nutrients such as the Canada Basin and offshore of the Mackenzie Shelf. In summary, we found that while some Arctic HF were successful over a range of conditions, others could be specialists that occur under particular conditions. We conclude that tracking species level diversity in HF not only is feasible but also provides a potential tool for understanding the responses of marine microbial ecosystems to rapidly changing ice regimes. PMID:25595764

  16. On Keelungia pulex nov. gen. et nov. sp., a heterotrophic euglenoid flagellate that lacks pellicular plates (Euglenophyceae, Euglenida).

    PubMed

    Chan, Ya-Fan; Moestrup, Øjvind; Chang, Jeng

    2013-01-01

    Keelungia pulex nov. gen. et nov. sp. is described from coastal waters of NE Taiwan. The new species is heterotrophic and feeds on bacteria. Cells are oblong-ovoid, biflagellate and glide along the sides of the flask. Each cell is approximately 8-11μm long, and one of the smallest euglenoid flagellates presently known. Keelungia lacks pellicular plates and in this respect resembles diplonemids and Symbiontida, which are thought to be among the basal groups of Euglenozoa. SEM showed the presence of 10 evenly spaced longitudinal striae in the cell surface, but the striae are difficult to see in the light microscope. TEM showed each stria to comprise a double set of very low longitudinal ridges separated by a shallow furrow, and supported by ca 5 microtubules beneath the plasmalemma, unlike the situation in diplonemids and Symbiontida. The cell surface was further subtended by an extensive system of rough cisternae of endoplasmic reticulum. Keelungia pulex is phylogenetically related to species of Ploeotia and to Lentomonas applanata, but differs in details of the feeding apparatus and in the absence of pellicular plates. Sequencing of SSU rDNA indicates that Ploeotia, Keelungia and Entosiphon form a clade near the base of the euglenoid phylogenetic tree. PMID:22698812

  17. Biogeography of heterotrophic flagellate populations indicates the presence of generalist and specialist taxa in the Arctic Ocean.

    PubMed

    Thaler, Mary; Lovejoy, Connie

    2015-03-01

    Heterotrophic marine flagellates (HF) are ubiquitous in the world's oceans and represented in nearly all branches of the domain Eukaryota. However, the factors determining distributions of major taxonomic groups are poorly known. The Arctic Ocean is a good model environment for examining the distribution of functionally similar but phylogenetically diverse HF because the physical oceanography and annual ice cycles result in distinct environments that could select for microbial communities or favor specific taxa. We reanalyzed new and previously published high-throughput sequencing data from multiple studies in the Arctic Ocean to identify broad patterns in the distribution of individual taxa. HF accounted for fewer than 2% to over one-half of the reads from the water column and for up to 60% of reads from ice, which was dominated by Cryothecomonas. In the water column, many HF phylotypes belonging to Telonemia and Picozoa, uncultured marine stramenopiles (MAST), and choanoflagellates were geographically widely distributed. However, for two groups in particular, Telonemia and Cryothecomonas, some species level taxa showed more restricted distributions. For example, several phylotypes of Telonemia favored open waters with lower nutrients such as the Canada Basin and offshore of the Mackenzie Shelf. In summary, we found that while some Arctic HF were successful over a range of conditions, others could be specialists that occur under particular conditions. We conclude that tracking species level diversity in HF not only is feasible but also provides a potential tool for understanding the responses of marine microbial ecosystems to rapidly changing ice regimes.

  18. Pyogenic Flexor Tenosynovitis Caused by Shewanella algae.

    PubMed

    Fluke, Erin C; Carayannopoulos, Nikoletta L; Lindsey, Ronald W

    2016-07-01

    Pyogenic flexor tenosynovitis is an orthopedic emergency most commonly caused by Staphylococcus aureus and streptococci and occasionally, when associated with water exposure, Mycobacterium marinum. Shewanella algae, a gram-negative bacillus found in warm saltwater environments, has infrequently been reported to cause serious soft tissue infections and necrosis. In this case, S. algae caused complicated flexor tenosynovitis requiring open surgical irrigation and debridement. Flexor tenosynovitis caused by S. algae rapidly presented with all 4 Kanavel cardinal signs as well as subcutaneous purulence, ischemia, and necrosis, thus meeting the requirements for Pang et al group III classification of worst prognosis. Because of its rarity and virulence, S. algae should always be considered in cases of flexor tenosynovitis associated with traumatic water exposure to treat and minimize morbidity appropriately.

  19. 2011 Biomass Program Platform Peer Review: Algae

    SciTech Connect

    Yang, Joyce

    2012-02-01

    This document summarizes the recommendations and evaluations provided by an independent external panel of experts at the 2011 U.S. Department of Energy Biomass Program’s Algae Platform Review meeting.

  20. Collection, Isolation and Culture of Marine Algae.

    ERIC Educational Resources Information Center

    James, Daniel E.

    1984-01-01

    Methods of collecting, isolating, and culturing microscopic and macroscopic marine algae are described. Three different culture media list of chemicals needed and procedures for preparing Erdschreiber's and Provasoli's E. S. media. (BC)

  1. Stochastic Forecasting of Algae Blooms in Lakes

    SciTech Connect

    Wang, Peng; Tartakovsky, Daniel M.; Tartakovsky, Alexandre M.

    2013-01-03

    We consider a general framework to predict the development of harmful algal blooms (HABs) in a lake driven by uncertain parameters. To quantify the concentration uncertainty of those algae groups via their joint probabilistic density function (PDF), we explore an approach based on the Fokker-Planck equation. Our result is presented in an example where abundant nutrients contribute to the proliferation of cyanobacteria and other minor algae groups.

  2. Antioxidant Activity of Hawaiian Marine Algae

    PubMed Central

    Kelman, Dovi; Posner, Ellen Kromkowski; McDermid, Karla J.; Tabandera, Nicole K.; Wright, Patrick R.; Wright, Anthony D.

    2012-01-01

    Marine algae are known to contain a wide variety of bioactive compounds, many of which have commercial applications in pharmaceutical, medical, cosmetic, nutraceutical, food and agricultural industries. Natural antioxidants, found in many algae, are important bioactive compounds that play an important role against various diseases and ageing processes through protection of cells from oxidative damage. In this respect, relatively little is known about the bioactivity of Hawaiian algae that could be a potential natural source of such antioxidants. The total antioxidant activity of organic extracts of 37 algal samples, comprising of 30 species of Hawaiian algae from 27 different genera was determined. The activity was determined by employing the FRAP (Ferric Reducing Antioxidant Power) assays. Of the algae tested, the extract of Turbinaria ornata was found to be the most active. Bioassay-guided fractionation of this extract led to the isolation of a variety of different carotenoids as the active principles. The major bioactive antioxidant compound was identified as the carotenoid fucoxanthin. These results show, for the first time, that numerous Hawaiian algae exhibit significant antioxidant activity, a property that could lead to their application in one of many useful healthcare or related products as well as in chemoprevention of a variety of diseases including cancer. PMID:22412808

  3. Carotenoids in algae: distributions, biosyntheses and functions.

    PubMed

    Takaichi, Shinichi

    2011-01-01

    For photosynthesis, phototrophic organisms necessarily synthesize not only chlorophylls but also carotenoids. Many kinds of carotenoids are found in algae and, recently, taxonomic studies of algae have been developed. In this review, the relationship between the distribution of carotenoids and the phylogeny of oxygenic phototrophs in sea and fresh water, including cyanobacteria, red algae, brown algae and green algae, is summarized. These phototrophs contain division- or class-specific carotenoids, such as fucoxanthin, peridinin and siphonaxanthin. The distribution of α-carotene and its derivatives, such as lutein, loroxanthin and siphonaxanthin, are limited to divisions of Rhodophyta (macrophytic type), Cryptophyta, Euglenophyta, Chlorarachniophyta and Chlorophyta. In addition, carotenogenesis pathways are discussed based on the chemical structures of carotenoids and known characteristics of carotenogenesis enzymes in other organisms; genes and enzymes for carotenogenesis in algae are not yet known. Most carotenoids bind to membrane-bound pigment-protein complexes, such as reaction center, light-harvesting and cytochrome b(6)f complexes. Water-soluble peridinin-chlorophyll a-protein (PCP) and orange carotenoid protein (OCP) are also established. Some functions of carotenoids in photosynthesis are also briefly summarized.

  4. Biogas production experimental research using algae.

    PubMed

    Baltrėnas, Pranas; Misevičius, Antonas

    2015-01-01

    The current study is on the the use of macro-algae as feedstock for biogas production. Three types of macro-algae, Cladophora glomerata (CG), Chara fragilis (CF), and Spirogyra neglecta (SN), were chosen for this research. The experimental studies on biogas production were carried out with these algae in a batch bioreactor. In the bioreactor was maintained 35 ± 1°C temperature. The results showed that the most appropriate macro-algae for biogas production are Spirogyra neglecta (SN) and Cladophora glomerata (CG). The average amount of biogas obtained from the processing of SN - 0.23 m(3)/m(3)d, CG - 0.20 m(3)/m(3)d, and CF - 0.12 m(3)/m(3)d. Considering the concentration of methane obtained during the processing of SN and CG, which after eight days and until the end of the experiment exceeded 60%, it can be claimed that biogas produced using these algae is valuable. When processing CF, the concentration of methane reached the level of 50% only by the final day of the experiment, which indicates that this alga is less suitable for biogas production.

  5. Against All Odds: Trehalose-6-Phosphate Synthase and Trehalase Genes in the Bdelloid Rotifer Adineta vaga Were Acquired by Horizontal Gene Transfer and Are Upregulated during Desiccation

    PubMed Central

    Hespeels, Boris; Li, Xiang; Flot, Jean-François; Pigneur, Lise-Marie; Malaisse, Jeremy; Da Silva, Corinne; Van Doninck, Karine

    2015-01-01

    The disaccharide sugar trehalose is essential for desiccation resistance in most metazoans that survive dryness; however, neither trehalose nor the enzymes involved in its metabolism have ever been detected in bdelloid rotifers despite their extreme resistance to desiccation. Here we screened the genome of the bdelloid rotifer Adineta vaga for genes involved in trehalose metabolism. We discovered a total of four putative trehalose-6-phosphate synthase (TPS) and seven putative trehalase (TRE) gene copies in the genome of this ameiotic organism; however, no trehalose-6-phosphate phosphatase (TPP) gene or domain was detected. The four TPS copies of A. vaga appear more closely related to plant and fungi proteins, as well as to some protists, whereas the seven TRE copies fall in bacterial clades. Therefore, A. vaga likely acquired its trehalose biosynthesis and hydrolysis genes by horizontal gene transfers. Nearly all residues important for substrate binding in the predicted TPS domains are highly conserved, supporting the hypothesis that several copies of the genes might be functional. Besides, RNAseq library screening showed that trehalase genes were highly expressed compared to TPS genes, explaining probably why trehalose had not been detected in previous studies of bdelloids. A strong overexpression of their TPS genes was observed when bdelloids enter desiccation, suggesting a possible signaling role of trehalose-6-phosphate or trehalose in this process. PMID:26161530

  6. Acute toxicity screening of reservoir water and sediment using rotifers (Rotox{reg_sign}) and light emitting bacteria (Microtox{reg_sign}), reservoir vital signs monitoring, 1991

    SciTech Connect

    Moses, J.; Wade, D.C.

    1992-03-01

    Toxicological screening of reservoir sediments (porewater or interstitial water) and reservoir water (collected three meters above the sediments) was initiated in fourteen Tennessee River mainstem impoundments during the summer of 1990 as part of TVA`s Reservoir Vital Signs monitoring. Twenty-four stations representing transition-zone and forebay reservoir habitats were identified for study. Toxicity test methods evaluated acute response of the freshwater rotifer Brachionus calyciflorus (Rotox{trademark}) and the light emitting bacterium Photobacterium phosphoreum (Microtox{trademark}). The second series of Vital Signstoxicity biomonitoring tests was conducted during the summer of 1991. Results of this study indicated toxicity at several locations. The Vital Signs Reservoir Monitoring project allows several years of testing to establish toxicity baseline data and identify trends. Comparison of results from the first two years of testing show that Wilson Reservoir forebay (TRM 260.8) and Nickajack Reservoir forebay (TRM 425.5) bothexhibited mild toxicity to Microtox{trademark} in 1990 and toxicity to rotifers in 1991. No other stations exhibited toxicity both years.

  7. Modulated expression and enzymatic activity of the monogonont rotifer Brachionus koreanus Cu/Zn- and Mn-superoxide dismutase (SOD) in response to environmental biocides.

    PubMed

    Kim, Bo-Mi; Lee, Jin Wuk; Seo, Jung Soo; Shin, Kyung-Hoon; Rhee, Jae-Sung; Lee, Jae-Seong

    2015-02-01

    Superoxide dismutases (SODs) are important antioxidant enzymes whose expression levels are often used as biomarkers for oxidative stress. To investigate the biomarker potential of the monogonont rotifer Brachionus koreanus SOD genes, the full-length Cu/Zn-SOD (Bk-Cu/Zn-SOD) and Mn-SOD (Bk-Mn-SOD) genes were cloned from genomic DNA and characterized. All amino acid residues involved in the formation of tertiary structure and metal binding in Bk-Cu/Zn-SOD and Bk-Mn-SOD were highly conserved across species. Phylogenetic analysis revealed that Bk-Mn-SOD, in particular, was closely clustered with mitochondrial Mn-SOD. Transcript analysis after exposure to six different biocides (alachlor, chlorpyrifos, dimethoate, endosulfan, lindane, and molinate) revealed that the transcriptional level of Bk-Cu/Zn-SOD was significantly increased in a dose-dependent manner. In contrast, the level of Bk-Mn-SOD transcript was significantly increased compared with control cells in response to chlorpyrifos, endosulfan, and molinate at their no observed effect concentrations (NOECs). However, exposure to alachlor, chlorpyrifos, and molinate significantly reduced the enzymatic activity of total SOD protein, while a decreased pattern was observed in all biocide treatments. Taken together, these results indicate that exposure to waterborne environmental biocides induces the transcription of Bk-Cu/Zn-SOD and Bk-Mn-SOD, but inhibits the enzymatic activity of Bk-SODs. These results contribute to our understanding of the modes of action of oxidative stress-mediating biocides on rotifer.

  8. Against All Odds: Trehalose-6-Phosphate Synthase and Trehalase Genes in the Bdelloid Rotifer Adineta vaga Were Acquired by Horizontal Gene Transfer and Are Upregulated during Desiccation.

    PubMed

    Hespeels, Boris; Li, Xiang; Flot, Jean-François; Pigneur, Lise-Marie; Malaisse, Jeremy; Da Silva, Corinne; Van Doninck, Karine

    2015-01-01

    The disaccharide sugar trehalose is essential for desiccation resistance in most metazoans that survive dryness; however, neither trehalose nor the enzymes involved in its metabolism have ever been detected in bdelloid rotifers despite their extreme resistance to desiccation. Here we screened the genome of the bdelloid rotifer Adineta vaga for genes involved in trehalose metabolism. We discovered a total of four putative trehalose-6-phosphate synthase (TPS) and seven putative trehalase (TRE) gene copies in the genome of this ameiotic organism; however, no trehalose-6-phosphate phosphatase (TPP) gene or domain was detected. The four TPS copies of A. vaga appear more closely related to plant and fungi proteins, as well as to some protists, whereas the seven TRE copies fall in bacterial clades. Therefore, A. vaga likely acquired its trehalose biosynthesis and hydrolysis genes by horizontal gene transfers. Nearly all residues important for substrate binding in the predicted TPS domains are highly conserved, supporting the hypothesis that several copies of the genes might be functional. Besides, RNAseq library screening showed that trehalase genes were highly expressed compared to TPS genes, explaining probably why trehalose had not been detected in previous studies of bdelloids. A strong overexpression of their TPS genes was observed when bdelloids enter desiccation, suggesting a possible signaling role of trehalose-6-phosphate or trehalose in this process.

  9. Acute toxicity screening of reservoir water and sediment using rotifers (Rotox[reg sign]) and light emitting bacteria (Microtox[reg sign]), reservoir vital signs monitoring, 1991

    SciTech Connect

    Moses, J.; Wade, D.C.

    1992-03-01

    Toxicological screening of reservoir sediments (porewater or interstitial water) and reservoir water (collected three meters above the sediments) was initiated in fourteen Tennessee River mainstem impoundments during the summer of 1990 as part of TVA's Reservoir Vital Signs monitoring. Twenty-four stations representing transition-zone and forebay reservoir habitats were identified for study. Toxicity test methods evaluated acute response of the freshwater rotifer Brachionus calyciflorus (Rotox[trademark]) and the light emitting bacterium Photobacterium phosphoreum (Microtox[trademark]). The second series of Vital Signstoxicity biomonitoring tests was conducted during the summer of 1991. Results of this study indicated toxicity at several locations. The Vital Signs Reservoir Monitoring project allows several years of testing to establish toxicity baseline data and identify trends. Comparison of results from the first two years of testing show that Wilson Reservoir forebay (TRM 260.8) and Nickajack Reservoir forebay (TRM 425.5) bothexhibited mild toxicity to Microtox[trademark] in 1990 and toxicity to rotifers in 1991. No other stations exhibited toxicity both years.

  10. Adverse Effects, Expression of the Bk-CYP3045C1 Gene, and Activation of the ERK Signaling Pathway in the Water Accommodated Fraction-Exposed Rotifer.

    PubMed

    Won, Eun-Ji; Kim, Ryeo-Ok; Kang, Hye-Min; Kim, Hui-Su; Hwang, Dae-Sik; Han, Jeonghoon; Lee, Young Hwan; Hwang, Un-Ki; Zhou, Bingsheng; Lee, Su-Jae; Lee, Jae-Seong

    2016-06-01

    To examine the deleterious effects of the water accommodated fraction (WAF) of crude oil, the growth curve, fecundity, and lifespan of the monogonont rotifer (Brachionus koreanus) were measured for 24 h in response to three different doses (0.2×, 0.4×, and 0.8×) of WAFs. A higher dose of WAFs significantly reduced the fecundity and lifespan. A rotifer 32K microarray chip showed that the Bk-CYP3045C1 gene had the highest expression. Of the 25 entire CYP genes, the Bk-CYP3045C1 gene showed a significant expression for different doses and times in response to WAFs and chemical components of WAFs (naphthalene and phenanthrene); also, glutathione S-transferase genes, ABC transporter, and other genes showed dose responses upon exposure to 80% WAF over time. Different doses of WAFs increased the oxidative stress with an induction of reactive oxygen species (ROS) and a depletion of glutathione (GSH). Exposure to WAFs did not show toxic effects on survivability in B. koreanus; however, toxicity to WAFs was shown when piperonyl butoxide, a potent inhibitor of cytochrome P450 (CYP) enzymes, was added. This toxicity was dose-dependent. After WAFs exposure, p-ERK was activated over time in response to WAFs, which suggests that WAFs can be activated by the p-ERK signaling pathway.

  11. SCALE FORMATION IN CHRYSOPHYCEAN ALGAE

    PubMed Central

    Brown, R. Malcolm; Franke, Werner W.; Kleinig, Hans; Falk, Heinz; Sitte, Peter

    1970-01-01

    The cell wall of the marine chrysophycean alga Pleurochrysis scherfellii is composed of distinct wall fragments embedded in a gelatinous mass. The latter is a polysaccharide of pectic character which is rich in galactose and ribose. These wall fragments are identified as scales. They have been isolated and purified from the vegetative mother cell walls after zoospore formation. Their ultrastructure is described in an electron microscope study combining sectioning, freeze-etch, and negative staining techniques. The scales consist of a layer of concentrically arranged microfibrils (ribbons with cross-sections of 12 to 25 x 25 to 40 A) and underlying radial fibrils of similar dimensions. Such a network-plate is densely coated with particles which are assumed to be identical to the pectic component. The microfibrils are resistant to strong alkaline treatment and have been identified as cellulose by different methods, including sugar analysis after total hydrolysis, proton resonance spectroscopical examination (NMR spectroscopy) of the benzoylated product, and diverse histochemical tests. The formation and secretion of the scales can be followed along the maturing Golgi cisternae starting from a pronounced dilated "polymerization center" as a completely intracisternal process which ends in the exocytotic extrusion of the scales. The scales reveal the very same ultrastructure within the Golgi cisternae as they do in the cell wall. The present finding represents the first evidence on cellulose formation by the Golgi apparatus and is discussed in relation to a basic scheme for cellulose synthesis in plant cells in general. PMID:5513606

  12. Hyperspectral imaging of snow algae and green algae from aeroterrestrial habitats

    PubMed Central

    Holzinger, Andreas; Allen, Michael C.; Deheyn, Dimitri D.

    2016-01-01

    Snow algae and green algae living in aeroterrestrial habitats are ideal obbjects to study adaptation to high light irradiation. Here, we used a detailed description of the spectral properties as a proxy for photo-acclimation/protection in snow algae (Chlamydomonas nivalis, Chlainomonas sp. and Chloromonas sp.) and charopyhte green algae (Zygnema sp., Zygogonium ericetorum and Klebsormidium crenulatum). The hyperspectral microscopic mapping and imaging technique allowed us to acquire total absorbance spectra of these microalgae in the waveband of 400-900 nm. Particularly in Chlamydomonas nivalis and Chlainomonas sp., a high absorbance in the wave band of 400-550 nm was observed, due to naturally occurring secondary carotenoids; in Chloromonas sp. and in the charopyhte algae this was missing, the latter being close relatives to land plants. To investigate if cellular water loss has an influence on the spectral properties, the cells were plasmolysed in sorbitol or desiccated at ambient air. While in snow algae, these treatments did not change the spectral properties, in the charopyhte algae the condensation of the cytoplasm and plastids increased the absorbance in the lower waveband of 400 – 500 nm. These changes might be ecologically relevant and photoprotective, as aeroterrestrial algae are naturally exposed to occasional water limitation, leading to desiccation, which are conditions usually occurring together with higher irradiation. PMID:27442511

  13. Hyperspectral imaging of snow algae and green algae from aeroterrestrial habitats.

    PubMed

    Holzinger, Andreas; Allen, Michael C; Deheyn, Dimitri D

    2016-09-01

    Snow algae and green algae living in aeroterrestrial habitats are ideal objects to study adaptation to high light irradiation. Here, we used a detailed description of the spectral properties as a proxy for photo-acclimation/protection in snow algae (Chlamydomonas nivalis, Chlainomonas sp. and Chloromonas sp.) and charophyte green algae (Zygnema sp., Zygogonium ericetorum and Klebsormidium crenulatum). The hyperspectral microscopic mapping and imaging technique allowed us to acquire total absorption spectra of these microalgae in the waveband of 400-900nm. Particularly in Chlamydomonas nivalis and Chlainomonas sp., a high absorbance between 400-550nm was observed, due to naturally occurring secondary carotenoids; in Chloromonas sp. and in the charopyhte algae this high absorbance was missing, the latter being close relatives to land plants. To investigate if cellular water loss has an influence on the spectral properties, the cells were plasmolysed in sorbitol or desiccated at ambient air. While in snow algae, these treatments did hardly change the spectral properties, in the charopyhte algae the condensation of the cytoplasm and plastids increased the absorbance in the lower waveband of 400-500nm. These changes might be ecologically relevant and photoprotective, as aeroterrestrial algae are naturally exposed to occasional water limitation, leading to desiccation, which are conditions usually occurring together with higher irradiation. PMID:27442511

  14. Hyperspectral imaging of snow algae and green algae from aeroterrestrial habitats.

    PubMed

    Holzinger, Andreas; Allen, Michael C; Deheyn, Dimitri D

    2016-09-01

    Snow algae and green algae living in aeroterrestrial habitats are ideal objects to study adaptation to high light irradiation. Here, we used a detailed description of the spectral properties as a proxy for photo-acclimation/protection in snow algae (Chlamydomonas nivalis, Chlainomonas sp. and Chloromonas sp.) and charophyte green algae (Zygnema sp., Zygogonium ericetorum and Klebsormidium crenulatum). The hyperspectral microscopic mapping and imaging technique allowed us to acquire total absorption spectra of these microalgae in the waveband of 400-900nm. Particularly in Chlamydomonas nivalis and Chlainomonas sp., a high absorbance between 400-550nm was observed, due to naturally occurring secondary carotenoids; in Chloromonas sp. and in the charopyhte algae this high absorbance was missing, the latter being close relatives to land plants. To investigate if cellular water loss has an influence on the spectral properties, the cells were plasmolysed in sorbitol or desiccated at ambient air. While in snow algae, these treatments did hardly change the spectral properties, in the charopyhte algae the condensation of the cytoplasm and plastids increased the absorbance in the lower waveband of 400-500nm. These changes might be ecologically relevant and photoprotective, as aeroterrestrial algae are naturally exposed to occasional water limitation, leading to desiccation, which are conditions usually occurring together with higher irradiation.

  15. High Genetic Diversity and Fine-Scale Spatial Structure in the Marine Flagellate Oxyrrhis marina (Dinophyceae) Uncovered by Microsatellite Loci

    PubMed Central

    Lowe, Chris D.; Montagnes, David J. S.; Martin, Laura E.; Watts, Phillip C.

    2010-01-01

    Free-living marine protists are often assumed to be broadly distributed and genetically homogeneous on large spatial scales. However, an increasing application of highly polymorphic genetic markers (e.g., microsatellites) has provided evidence for high genetic diversity and population structuring on small spatial scales in many free-living protists. Here we characterise a panel of new microsatellite markers for the common marine flagellate Oxyrrhis marina. Nine microsatellite loci were used to assess genotypic diversity at two spatial scales by genotyping 200 isolates of O. marina from 6 broad geographic regions around Great Britain and Ireland; in one region, a single 2 km shore line was sampled intensively to assess fine-scale genetic diversity. Microsatellite loci resolved between 1–6 and 7–23 distinct alleles per region in the least and most variable loci respectively, with corresponding variation in expected heterozygosities (He) of 0.00–0.30 and 0.81–0.93. Across the dataset, genotypic diversity was high with 183 genotypes detected from 200 isolates. Bayesian analysis of population structure supported two model populations. One population was distributed across all sampled regions; the other was confined to the intensively sampled shore, and thus two distinct populations co-occurred at this site. Whilst model-based analysis inferred a single UK-wide population, pairwise regional FST values indicated weak to moderate population sub-division (0.01–0.12), but no clear correlation between spatial and genetic distance was evident. Data presented in this study highlight extensive genetic diversity for O. marina; however, it remains a substantial challenge to uncover the mechanisms that drive genetic diversity in free-living microorganisms. PMID:21203414

  16. High genetic diversity and fine-scale spatial structure in the marine flagellate Oxyrrhis marina (Dinophyceae) uncovered by microsatellite loci.

    PubMed

    Lowe, Chris D; Montagnes, David J S; Martin, Laura E; Watts, Phillip C

    2010-01-01

    Free-living marine protists are often assumed to be broadly distributed and genetically homogeneous on large spatial scales. However, an increasing application of highly polymorphic genetic markers (e.g., microsatellites) has provided evidence for high genetic diversity and population structuring on small spatial scales in many free-living protists. Here we characterise a panel of new microsatellite markers for the common marine flagellate Oxyrrhis marina. Nine microsatellite loci were used to assess genotypic diversity at two spatial scales by genotyping 200 isolates of O. marina from 6 broad geographic regions around Great Britain and Ireland; in one region, a single 2 km shore line was sampled intensively to assess fine-scale genetic diversity. Microsatellite loci resolved between 1-6 and 7-23 distinct alleles per region in the least and most variable loci respectively, with corresponding variation in expected heterozygosities (H(e)) of 0.00-0.30 and 0.81-0.93. Across the dataset, genotypic diversity was high with 183 genotypes detected from 200 isolates. Bayesian analysis of population structure supported two model populations. One population was distributed across all sampled regions; the other was confined to the intensively sampled shore, and thus two distinct populations co-occurred at this site. Whilst model-based analysis inferred a single UK-wide population, pairwise regional F(ST) values indicated weak to moderate population sub-division (0.01-0.12), but no clear correlation between spatial and genetic distance was evident. Data presented in this study highlight extensive genetic diversity for O. marina; however, it remains a substantial challenge to uncover the mechanisms that drive genetic diversity in free-living microorganisms.

  17. PPR proteins of green algae.

    PubMed

    Tourasse, Nicolas J; Choquet, Yves; Vallon, Olivier

    2013-01-01

    Using the repeat finding algorithm FT-Rep, we have identified 154 pentatricopeptide repeat (PPR) proteins in nine fully sequenced genomes from green algae (with a total of 1201 repeats) and grouped them in 47 orthologous groups. All data are available in a database, PPRdb, accessible online at http://giavap-genomes.ibpc.fr/ppr. Based on phylogenetic trees generated from the repeats, we propose evolutionary scenarios for PPR proteins. Two PPRs are clearly conserved in the entire green lineage: MRL1 is a stabilization factor for the rbcL mRNA, while HCF152 binds in plants to the psbH-petB intergenic region. MCA1 (the stabilization factor for petA) and PPR7 (a short PPR also acting on chloroplast mRNAs) are conserved across the entire Chlorophyta. The other PPRs are clade-specific, with evidence for gene losses, duplications, and horizontal transfer. In some PPR proteins, an additional domain found at the C terminus provides clues as to possible functions. PPR19 and PPR26 possess a methyltransferase_4 domain suggesting involvement in RNA guanosine methylation. PPR18 contains a C-terminal CBS domain, similar to the CBSPPR1 protein found in nucleoids. PPR16, PPR29, PPR37, and PPR38 harbor a SmR (MutS-related) domain similar to that found in land plants pTAC2, GUN1, and SVR7. The PPR-cyclins PPR3, PPR4, and PPR6, in addition, contain a cyclin domain C-terminal to their SmR domain. PPR31 is an unusual PPR-cyclin containing at its N terminus an OctotricoPeptide Repeat (OPR) and a RAP domain. We consider the possibility that PPR proteins with a SmR domain can introduce single-stranded nicks in the plastid chromosome.

  18. PPR proteins of green algae

    PubMed Central

    Tourasse, Nicolas J; Choquet, Yves; Vallon, Olivier

    2013-01-01

    Using the repeat finding algorithm FT-Rep, we have identified 154 pentatricopeptide repeat (PPR) proteins in nine fully sequenced genomes from green algae (with a total of 1201 repeats) and grouped them in 47 orthologous groups. All data are available in a database, PPRdb, accessible online at http://giavap-genomes.ibpc.fr/ppr. Based on phylogenetic trees generated from the repeats, we propose evolutionary scenarios for PPR proteins. Two PPRs are clearly conserved in the entire green lineage: MRL1 is a stabilization factor for the rbcL mRNA, while HCF152 binds in plants to the psbH-petB intergenic region. MCA1 (the stabilization factor for petA) and PPR7 (a short PPR also acting on chloroplast mRNAs) are conserved across the entire Chlorophyta. The other PPRs are clade-specific, with evidence for gene losses, duplications, and horizontal transfer. In some PPR proteins, an additional domain found at the C terminus provides clues as to possible functions. PPR19 and PPR26 possess a methyltransferase_4 domain suggesting involvement in RNA guanosine methylation. PPR18 contains a C-terminal CBS domain, similar to the CBSPPR1 protein found in nucleoids. PPR16, PPR29, PPR37, and PPR38 harbor a SmR (MutS-related) domain similar to that found in land plants pTAC2, GUN1, and SVR7. The PPR-cyclins PPR3, PPR4, and PPR6, in addition, contain a cyclin domain C-terminal to their SmR domain. PPR31 is an unusual PPR-cyclin containing at its N terminus an OctotricoPeptide Repeat (OPR) and a RAP domain. We consider the possibility that PPR proteins with a SmR domain can introduce single-stranded nicks in the plastid chromosome. PMID:24021981

  19. [Algae removal of high algae raw water by coagulation enhanced by ozonation].

    PubMed

    Liu, Hai-Long; Yang, Dong; Zhao, Zhi-Yong; Li, Zheng-Jian; Cheng, Fang-Qin

    2009-07-15

    Apparent molecular weight distribution (AMWD) and resin fractionation were used to characterize organic matters of the raw water. Removal of algae, change and removal of dissolved organic carbon (DOC), disinfection by products (DBPs) control during the preozonation enhanced coagulation treatments in the jar-scale and pilot-scale experiment were studied. Algae activity (AA) was measured and used to elucidate the mechanisms of algae removal by above treatments. Results show that algae removal can be improved distinctively by proper preozonation, as the ozone dose 1.0 mg x L(-1), for instance. Algae removal could be increased from 55%-85% by traditional coagulation to 95% by enhanced coagulation after preozonation; and the best removal achieved 99.3% with ozone 1.0 mg x L(-1) and PACl 3.0 mg x L(-1); the residual THMFP (Trihalomethanes formation potential) was lowered from 117 microg x L(-1) by traditional coagulation to 46 microg x L(-1). But higher dose of ozone (as > or = 2.0 mg x L(-1)) impairs organic matter removal, although it decreases algae activity further. Significant differences were found in algae removal by AA detection between ozonation and traditional coagulation. Traditional coagulation had little effect on AA no matter the different PAC1 doses; while AA decreased clearly after ozonation. AA was lowered below 12 under 0.5-2.0 mg x L(-1) ozonation; and it kept decreasing with increase of ozone dosage. During the following coagulation, coagulant or some of its hydrolysised components enhanced the AA decrease by ozonation. Compared to the method of normal microscopy counting, AA test expresses the influence of algae living state by water treatment processes more clearly; which would provide treatment process designer with more distinct information about algae removal mechanisms and how to arrange the treatment processes to improve algae removal.

  20. Biological toxicity of lanthanide elements on algae.

    PubMed

    Tai, Peidong; Zhao, Qing; Su, Dan; Li, Peijun; Stagnitti, Frank

    2010-08-01

    The biological toxicity of lanthanides on marine monocellular algae was investigated. The specific objective of this research was to establish the relationship between the abundance in the seawater of lanthanides and their biological toxicities on marine monocellular algae. The results showed that all single lanthanides had similar toxic effects on Skeletonema costatum. High concentrations of lanthanides (29.04+/-0.61 micromol L(-1)) resulted in 50% reduction in growth of algae compared to the controls (0 micromol L(-1)) after 96 h (96 h-EC50). The biological toxicity of 13 lanthanides on marine monocellular algae was unrelated with the abundance of different lanthanide elements in nature, and the "Harkins rule" was not appropriate for the lanthanides. A mixed solution that contained equivalent concentrations of each lanthanide element had the same inhibition effect on algae cells as each individual lanthanide element at the same total concentration. This phenomenon is unique compared to the groups of other elements in the periodic table. Hence, we speculate that the monocellular organisms might not be able to sufficiently differentiate between the almost chemically identical lanthanide elements.

  1. Studies on marine algae for haemagglutinic activity.

    PubMed

    Alam, M T; Usmanghani, K

    1994-07-01

    Lectins (agglutinins) are important in medical and immunological applications. Phytohaemagglutinins have been found useful in blood banking. Keeping in view of these facts, the marine algae found at Karachi coastal region have been screened for agglutinic activity by using human erythrocytes of A, B, AB and 0 group. Altogether 53 algal samples were collected and subjected to extraction, fractionation serial dilution and titre determinations. The total marine algae screened for haemagglutinic activity were 44 out of these 14, 13 and 17 belonged to Chlorophyta, Phaeophyta, and Rhodophyta respectively. Among these three groups the Rhodophyta showed the highest number of lytic activity. The green marine alga Valoniopsis pachynema showed a titre value between 2(2) and 2(3), which is statistically significant. In case of brown marine algae Colpomenia sinuosa was found to be active (titre 2(3)), while Dictyota dichotoma, D. indica and Iyengaria stellata, furnished week titre value as 2(2). The red marine algae screened were 17, out of these 4 spp. showed significant activity (titre 2(3)), and these are Gelidium usmanghani, Gracilaria foliifera Hypnea pannosa and Hynea valentiae. While Scinaia fascicularis, Scinaia indica and Champia parvula were found to be weak in their onset on human erythrocytes. The results obtained were quite in agreement with those reported in the literature. PMID:16414751

  2. Biological toxicity of lanthanide elements on algae.

    PubMed

    Tai, Peidong; Zhao, Qing; Su, Dan; Li, Peijun; Stagnitti, Frank

    2010-08-01

    The biological toxicity of lanthanides on marine monocellular algae was investigated. The specific objective of this research was to establish the relationship between the abundance in the seawater of lanthanides and their biological toxicities on marine monocellular algae. The results showed that all single lanthanides had similar toxic effects on Skeletonema costatum. High concentrations of lanthanides (29.04+/-0.61 micromol L(-1)) resulted in 50% reduction in growth of algae compared to the controls (0 micromol L(-1)) after 96 h (96 h-EC50). The biological toxicity of 13 lanthanides on marine monocellular algae was unrelated with the abundance of different lanthanide elements in nature, and the "Harkins rule" was not appropriate for the lanthanides. A mixed solution that contained equivalent concentrations of each lanthanide element had the same inhibition effect on algae cells as each individual lanthanide element at the same total concentration. This phenomenon is unique compared to the groups of other elements in the periodic table. Hence, we speculate that the monocellular organisms might not be able to sufficiently differentiate between the almost chemically identical lanthanide elements. PMID:20547408

  3. Controlled regular locomotion of algae cell microrobots.

    PubMed

    Xie, Shuangxi; Jiao, Niandong; Tung, Steve; Liu, Lianqing

    2016-06-01

    Algae cells can be considered as microrobots from the perspective of engineering. These organisms not only have a strong reproductive ability but can also sense the environment, harvest energy from the surroundings, and swim very efficiently, accommodating all these functions in a body of size on the order of dozens of micrometers. An interesting topic with respect to random swimming motions of algae cells in a liquid is how to precisely control them as microrobots such that they swim according to manually set routes. This study developed an ingenious method to steer swimming cells based on the phototaxis. The method used a varying light signal to direct the motion of the cells. The swimming trajectory, speed, and force of algae cells were analyzed in detail. Then the algae cell could be controlled to swim back and forth, and traverse a crossroad as a microrobot obeying specific traffic rules. Furthermore, their motions along arbitrarily set trajectories such as zigzag, and triangle were realized successfully under optical control. Robotize algae cells can be used to precisely transport and deliver cargo such as drug particles in microfluidic chip for biomedical treatment and pharmacodynamic analysis. The study findings are expected to bring significant breakthrough in biological drives and new biomedical applications.

  4. Estimation of alga growth stage and lipid content growth rate

    NASA Technical Reports Server (NTRS)

    Embaye, Tsegereda N. (Inventor); Trent, Jonathan D. (Inventor)

    2012-01-01

    Method and system for estimating a growth stage of an alga in an ambient fluid. Measured light beam absorption or reflection values through or from the alga and through an ambient fluid, in each of two or more wavelength sub-ranges, are compared with reference light beam absorption values for corresponding wavelength sub-ranges for in each alga growth stage to determine (1) which alga growth stage, if any, is more likely and (2) whether estimated lipid content of the alga is increasing or has peaked. Alga growth is preferably terminated when lipid content has approximately reached a maximum value.

  5. Genome of the red alga Porphyridium purpureum.

    PubMed

    Bhattacharya, Debashish; Price, Dana C; Chan, Cheong Xin; Qiu, Huan; Rose, Nicholas; Ball, Steven; Weber, Andreas P M; Arias, Maria Cecilia; Henrissat, Bernard; Coutinho, Pedro M; Krishnan, Anagha; Zäuner, Simone; Morath, Shannon; Hilliou, Frédérique; Egizi, Andrea; Perrineau, Marie-Mathilde; Yoon, Hwan Su

    2013-01-01

    The limited knowledge we have about red algal genomes comes from the highly specialized extremophiles, Cyanidiophyceae. Here, we describe the first genome sequence from a mesophilic, unicellular red alga, Porphyridium purpureum. The 8,355 predicted genes in P. purpureum, hundreds of which are likely to be implicated in a history of horizontal gene transfer, reside in a genome of 19.7 Mbp with 235 spliceosomal introns. Analysis of light-harvesting complex proteins reveals a nuclear-encoded phycobiliprotein in the alga. We uncover a complex set of carbohydrate-active enzymes, identify the genes required for the methylerythritol phosphate pathway of isoprenoid biosynthesis, and find evidence of sexual reproduction. Analysis of the compact, function-rich genome of P. purpureum suggests that ancestral lineages of red algae acted as mediators of horizontal gene transfer between prokaryotes and photosynthetic eukaryotes, thereby significantly enriching genomes across the tree of photosynthetic life.

  6. Algae control problems and practices workshop

    SciTech Connect

    Pryfogle, P.A.; Ghio, G.

    1996-09-01

    Western water resources are continuously facing increased demand from industry and the public. Consequently, many of these resources are required to perform multiple tasks as they cycle through the ecosystem. Many plants and animals depend upon these resources for growth. Algae are one group of plants associated with nutrient and energy cycles in many aquatic ecosystems. Although most freshwater algae are microscopic in size, they are capable of dominating and proliferating to the extent that the value of the water resource for both industrial and domestic needs is compromised. There is a great diversity of aquatic environments and systems in which algae may be found, and there are many varieties of treatment and control techniques available to reduce the impacts of excessive growth. This workshop was organized to exchange information about these control problems and practices.

  7. Genome of the red alga Porphyridium purpureum

    PubMed Central

    Bhattacharya, Debashish; Price, Dana C.; Xin Chan, Cheong; Qiu, Huan; Rose, Nicholas; Ball, Steven; Weber, Andreas P. M.; Cecilia Arias, Maria; Henrissat, Bernard; Coutinho, Pedro M.; Krishnan, Anagha; Zäuner, Simone; Morath, Shannon; Hilliou, Frédérique; Egizi, Andrea; Perrineau, Marie-Mathilde; Yoon, Hwan Su

    2013-01-01

    The limited knowledge we have about red algal genomes comes from the highly specialized extremophiles, Cyanidiophyceae. Here, we describe the first genome sequence from a mesophilic, unicellular red alga, Porphyridium purpureum. The 8,355 predicted genes in P. purpureum, hundreds of which are likely to be implicated in a history of horizontal gene transfer, reside in a genome of 19.7 Mbp with 235 spliceosomal introns. Analysis of light-harvesting complex proteins reveals a nuclear-encoded phycobiliprotein in the alga. We uncover a complex set of carbohydrate-active enzymes, identify the genes required for the methylerythritol phosphate pathway of isoprenoid biosynthesis, and find evidence of sexual reproduction. Analysis of the compact, function-rich genome of P. purpureum suggests that ancestral lineages of red algae acted as mediators of horizontal gene transfer between prokaryotes and photosynthetic eukaryotes, thereby significantly enriching genomes across the tree of photosynthetic life. PMID:23770768

  8. Turning Algae into Energy in New Mexico

    ScienceCinema

    Sayre, Richard; Olivares, Jose; Lammers, Peter

    2016-07-12

    Los Alamos National Laboratory, as part of the New Mexico Consortium - comprised of New Mexico's major research universities, the Lab, and key industry partners - is conducting research into using algae as a feed stock for a renewable source of fuels, and other products. There are hundreds of thousands of different algae species on Earth. They account for approximately half of the net photosynthesis on the planet, yet they have not been used in any kind of a large scale by humanity, with just a few exceptions. And yet, the biomass is easy to transform into useful products, including fuels, and they contain many other natural products that have high value. In this video Los Alamos and New Mexico State University scientists outline the opportunities and challenges of using science to turn algae into energy.

  9. Turning Algae into Energy in New Mexico

    SciTech Connect

    Sayre, Richard; Olivares, Jose; Lammers, Peter

    2013-07-29

    Los Alamos National Laboratory, as part of the New Mexico Consortium - comprised of New Mexico's major research universities, the Lab, and key industry partners - is conducting research into using algae as a feed stock for a renewable source of fuels, and other products. There are hundreds of thousands of different algae species on Earth. They account for approximately half of the net photosynthesis on the planet, yet they have not been used in any kind of a large scale by humanity, with just a few exceptions. And yet, the biomass is easy to transform into useful products, including fuels, and they contain many other natural products that have high value. In this video Los Alamos and New Mexico State University scientists outline the opportunities and challenges of using science to turn algae into energy.

  10. Microspectroscopy of the photosynthetic compartment of algae.

    PubMed

    Evangelista, Valtere; Frassanito, Anna Maria; Passarelli, Vincenzo; Barsanti, Laura; Gualtieri, Paolo

    2006-01-01

    We performed microspectroscopic evaluation of the pigment composition of the photosynthetic compartments of algae belonging to different taxonomic divisions and higher plants. The feasibility of microspectroscopy for discriminating among species and/or phylogenetic groups was tested on laboratory cultures. Gaussian bands decompositions and a fitting algorithm, together with fourth-derivative transformation of absorbance spectra, provided a reliable discrimination among chlorophylls a, b and c, phycobiliproteins and carotenoids. Comparative analysis of absorption spectra highlighted the evolutionary grouping of the algae into three main lineages in accordance with the most recent endosymbiotic theories.

  11. WASP7 BENTHIC ALGAE - MODEL THEORY AND USER'S GUIDE

    EPA Science Inventory

    The standard WASP7 eutrophication module includes nitrogen and phosphorus cycling, dissolved oxygen-organic matter interactions, and phytoplankton kinetics. In many shallow streams and rivers, however, the attached algae (benthic algae, or periphyton, attached to submerged substr...

  12. MANOMETRIC MEASUREMENTS OF PHOTOSYNTHESIS IN THE MARINE ALGA GIGARTINA

    PubMed Central

    Emerson, Robert; Green, Lowell

    1934-01-01

    A manometric method for measuring photosynthesis in marine algae is described. Photosynthesis in the red alga Gigartina harveyana is shown to be similar in all important respects to photosynthesis in Chlorella and other Chlorophyceae. PMID:19872816

  13. An Overview of Algae Biofuel Production and Potential Environmental Impact

    EPA Science Inventory

    Algae are among the most potentially significant sources of sustainable biofuels in the future of renewable energy. A feedstock with virtually unlimited applicability, algae can metabolize various waste streams (e.g., municipal wastewater, carbon dioxide from industrial flue gas)...

  14. [Accumulation of polycyclic arenes in Baltic Sea algae].

    PubMed

    Veldre, I A; Itra, A R; Paal'me, L P; Kukk, Kh A

    1985-01-01

    The paper presents data on the level of benzo(a)pyrene (BP) and some other polycyclic arenes in alga and phanerogam specimens from different gulfs of the Baltic Sea. Algae were shown to absorb BP from sea water. The mean concentration of BP in sea water was under 0.004 microgram/1, while in algae it ranged 0.1-21.2 micrograms/kg dry weight. Algae accumulate BP to a higher degree than phanerogams. The highest concentrations of BP were found in algae Enteromorpha while the lowest ones in Furcellaria. In annual green algae, BP level was higher in autumn, i. e. at the end of vegetation period, than in spring. Brown algae Fucus vesiculosus is recommended for monitoring polycyclic arene pollution in the area from Vormsi Island to Käsmu and green algae Cladophora or Enteromorpha in the eastern part of the Finnish Gulf.

  15. [Accumulation of polycyclic arenes in Baltic Sea algae].

    PubMed

    Veldre, I A; Itra, A R; Paal'me, L P; Kukk, Kh A

    1985-01-01

    The paper presents data on the level of benzo(a)pyrene (BP) and some other polycyclic arenes in alga and phanerogam specimens from different gulfs of the Baltic Sea. Algae were shown to absorb BP from sea water. The mean concentration of BP in sea water was under 0.004 microgram/1, while in algae it ranged 0.1-21.2 micrograms/kg dry weight. Algae accumulate BP to a higher degree than phanerogams. The highest concentrations of BP were found in algae Enteromorpha while the lowest ones in Furcellaria. In annual green algae, BP level was higher in autumn, i. e. at the end of vegetation period, than in spring. Brown algae Fucus vesiculosus is recommended for monitoring polycyclic arene pollution in the area from Vormsi Island to Käsmu and green algae Cladophora or Enteromorpha in the eastern part of the Finnish Gulf. PMID:4060672

  16. Use of Brown Algae to Demonstrate Natural Products Techniques.

    ERIC Educational Resources Information Center

    Porter, Lee A.

    1985-01-01

    Background information is provided on the natural products found in marine organisms in general and the brown algae in particular. Also provided are the procedures needed to isolate D-mannitol (a primary metabolite) and cholesterol from brown algae. (JN)

  17. Altered grazing patterns in an experimental copepod-alga ecosystem exposed to naphthalene and Kuwait crude oil

    SciTech Connect

    Vandermeulen, J.H.

    1986-02-01

    The authors became interested in the potential disruption of predator-prey relationships after they observed that naphthalene, as well as a number of oils, changed the swimming behavior of the unicellular flagellate alga Pavlova lutheri (formerly Monochrysis lutheri). Reasoning that alterations in the motility of a prey species would render it more susceptible to predation, the authors examined the hydrocarbon-induced changes in predation success in a simple two-member prey-predator system consisting only of P. lutheri and the marine copepod Calanus finmarchicus. The organisms were exposed, together, to low concentrations of either naphthalene or Kuwait crude oil dissolved in seawater, and the feeding efficiency of the copepods under these conditions was measured by counting the survival of algal cells. Naphthalene was chosen because it is a relatively simple toxic aromatic hydrocarbon, common to all crude oils and most refined products and their aqueous extracts. Kuwait crude oil was used as a representative oil mixture more commonly encountered under spillage conditions.

  18. Effect of pharmaceuticals exposure on acetylcholinesterase (AchE) activity and on the expression of AchE gene in the monogonont rotifer, Brachionus koreanus.

    PubMed

    Rhee, Jae-Sung; Kim, Bo-Mi; Jeong, Chang-Bum; Park, Heum Gi; Leung, Kenneth Mei Yee; Lee, Young-Mi; Lee, Jae-Seong

    2013-11-01

    Pharmaceuticals are widely used in human and veterinary medicine. However, they are emerging as a significant contaminant in aquatic environments through wastewater. Due to the persistent and accumulated properties of pharmaceuticals via the food web, their potential harmful effects on aquatic animals are a great concern. In this study, we investigated the effects of six pharmaceuticals: acetaminophen, ATP; atenolol, ATN; carbamazepine, CBZ; oxytetracycline, OTC; sulfamethoxazole, SMX; and trimethoprim, TMP on acetylcholinesterase (AChE; EC 3.1.1.7) activity and its transcript expression with chlorpyrifos (as a positive control) in the monogonont rotifer, Brachionus koreanus. ATP, CBZ, and TMP exposure also remarkably inhibited Bk-AChE activity at 100 μg/L (24 h) and 1000 μg/L (12 h and 24 h). ATP, CBZ, and TMP exposure showed a significant decrease in the Bk-AChE mRNA level in a concentration-dependent manner. However, in the case of OTC and SMX, a slight decrease in Bk-AChE mRNA expression was found but only at the highest concentration. The time-course experiments showed that ATP positively induced Bk-AChE mRNA 12 h after exposure at both 100 and 1000 μg/L, while the Bk-AChE mRNA expression was significantly downregulated over 6 to 24 h after exposure to 1000 μg/L of CBZ, OTC, SMX, and TMP. Our findings suggest that Bk-AChE would be a useful biomarker for risk assessment of pharmaceutical compounds as an early signal of their toxicity in aquatic environments. Particularly, ATP, CBZ, and TMP may have a toxic cholinergic effect on rotifer B. koreanus by inhibiting AChE activity. PMID:24028855

  19. Neonatal sepsis caused by Shewanella algae: A case report.

    PubMed

    Charles, Marie Victor Pravin; Srirangaraj, Sreenivasan; Kali, Arunava

    2015-01-01

    Sepsis remains a leading cause of mortality among neonates, especially in developing countries. Most cases of neonatal sepsis are attributed to Escherichia coli and other members of the Enterobacteriaceae family. Shewanella algae (S. algae) is a gram-negative saprophytic bacillus, commonly associated with the marine environment, which has been isolated from humans. Early onset neonatal sepsis caused by S. algae is uncommon. We report a case of S. algae blood stream infection in a newborn with early onset neonatal sepsis.

  20. 21 CFR 73.185 - Haematococcus algae meal.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Haematococcus algae meal. 73.185 Section 73.185... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.185 Haematococcus algae meal. (a) Identity. (1) The color additive haematococcus algae meal consists of the comminuted and dried cells of the...

  1. 21 CFR 73.185 - Haematococcus algae meal.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Haematococcus algae meal. 73.185 Section 73.185... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.185 Haematococcus algae meal. (a) Identity. (1) The color additive haematococcus algae meal consists of the comminuted and dried cells of the...

  2. 21 CFR 73.185 - Haematococcus algae meal.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Haematococcus algae meal. 73.185 Section 73.185... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.185 Haematococcus algae meal. (a) Identity. (1) The color additive haematococcus algae meal consists of the comminuted and dried cells of the...

  3. 21 CFR 73.185 - Haematococcus algae meal.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Haematococcus algae meal. 73.185 Section 73.185... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.185 Haematococcus algae meal. (a) Identity. (1) The color additive haematococcus algae meal consists of the comminuted and dried cells of the...

  4. 21 CFR 73.185 - Haematococcus algae meal.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Haematococcus algae meal. 73.185 Section 73.185... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.185 Haematococcus algae meal. (a) Identity. (1) The color additive haematococcus algae meal consists of the comminuted and dried cells of the...

  5. How to Identify and Control Water Weeds and Algae.

    ERIC Educational Resources Information Center

    Applied Biochemists, Inc., Mequon, WI.

    Included in this guide to water management are general descriptions of algae, toxic algae, weed problems in lakes, ponds, and canals, and general discussions of mechanical, biological and chemical control methods. In addition, pictures, descriptions, and recommended control methods are given for algae, 6 types of floating weeds, 18 types of…

  6. Research and development for algae-based technologies in Korea: a review of algae biofuel production.

    PubMed

    Hong, Ji Won; Jo, Seung-Woo; Yoon, Ho-Sung

    2015-03-01

    This review covers recent research and development (R&D) activities in the field of algae-based biofuels in Korea. As South Korea's energy policy paradigm has focused on the development of green energies, the government has funded several algae biofuel R&D consortia and pilot projects. Three major programs have been launched since 2009, and significant efforts are now being made to ensure a sustainable supply of algae-based biofuels. If these R&D projects are executed as planned for the next 10 years, they will enable us to overcome many technical barriers in algae biofuel technologies and help Korea to become one of the leading countries in green energy by 2020.

  7. Spirulina: The Alga That Can End Malnutrition.

    ERIC Educational Resources Information Center

    Fox, Ripley D.

    1985-01-01

    One approach to eliminating malnutrition worldwide is to grow spirulina in recycled village wastes. Spirulina is a blue-green alga and a natural concentrated food. Spirulina can give poor villages a nutritional food supplement they can grow themselves and can reduce infectious disease at the same time. (Author/RM)

  8. Fucoidans — sulfated polysaccharides of brown algae

    NASA Astrophysics Data System (ADS)

    Usov, Anatolii I.; Bilan, M. I.

    2009-08-01

    The methods of isolation of fucoidans and determination of their chemical structures are reviewed. The fucoidans represent sulfated polysaccharides of brown algae, the composition of which varies from simple fucan sulfates to complex heteropolysaccharides. The currently known structures of such biopolymers are presented. A variety of the biological activities of fucoidans is briefly summarised.

  9. Pheromone signaling during sexual reproduction in algae.

    PubMed

    Frenkel, Johannes; Vyverman, Wim; Pohnert, Georg

    2014-08-01

    Algae are found in all aquatic and many terrestrial habitats. They are dominant in phytoplankton and biofilms thereby contributing massively to global primary production. Since algae comprise photosynthetic representatives of the various protoctist groups their physiology and appearance is highly diverse. This diversity is also mirrored in their characteristic life cycles that exhibit various facets of ploidy and duration of the asexual phase as well as gamete morphology. Nevertheless, sexual reproduction in unicellular and colonial algae usually has as common motive that two specialized, sexually compatible haploid gametes establish physical contact and fuse. To guarantee mating success, processes during sexual reproduction are highly synchronized and regulated. This review focuses on sex pheromones of algae that play a key role in these processes. Especially, the diversity of sexual strategies as well as of the compounds involved are the focus of this contribution. Discoveries connected to algal pheromone chemistry shed light on the role of key evolutionary processes, including endosymbiotic events and lateral gene transfer, speciation and adaptation at all phylogenetic levels. But progress in this field might also in the future provide valid tools for the manipulation of aquaculture and environmental processes.

  10. Laser-fluorescence measurement of marine algae

    NASA Technical Reports Server (NTRS)

    Browell, E. V.

    1980-01-01

    Progress in remote sensing of algae by laser-induced fluorescence is subject of comprehensive report. Existing single-wavelength and four-wavelength systems are reviewed, and new expression for power received by airborne sensor is derived. Result differs by as much as factor of 10 from those previously reported. Detailed error analysis evluates factors affecting accuracy of laser-fluorosensor systems.

  11. Peroxisomal targeting signals in green algae.

    PubMed

    Shinozaki, Akiko; Sato, Nagisa; Hayashi, Yasuko

    2009-03-01

    Peroxisomal enzymatic proteins contain targeting signals (PTS) to enable their import into peroxisomes. These targeting signals have been identified as PTS1 and PTS2 in mammalian, yeast, and higher plant cells; however, no PTS2-like amino acid sequences have been observed in enzymes from the genome database of Cyanidiochyzon merolae (Bangiophyceae), a primitive red algae. In studies on the evolution of PTS, it is important to know when their sequences came to be the peroxisomal targeting signals for all living organisms. To this end, we identified a number of genes in the genome database of the green algae Chlamydomonas reinhardtii, which contains amino acid sequences similar to those found in plant PTS. In order to determine whether these sequences function as PTS in green algae, we expressed modified green fluorescent proteins (GFP) fused to these putative PTS peptides under the cauliflower mosaic virus 35S promoter. To confirm whether granular structures containing GFP-PTS fusion proteins accumulated in the peroxisomes of Closterium ehrenbergii, we observed these cells after the peroxisomes were stained with 3, 3'-diaminobenzidine. Our results confirm that the GFP-PTS fusion proteins indeed accumulated in the peroxisomes of these green algae. These findings suggest that the peroxisomal transport system for PTS1 and PTS2 is conserved in green algal cells and that our fusion proteins can be used to visualize peroxisomes in live cells.

  12. High diversity of the 'Spumella-like' flagellates: an investigation based on the SSU rRNA gene sequences of isolates from habitats located in six different geographic regions.

    PubMed

    Boenigk, Jens; Pfandl, Karin; Stadler, Peter; Chatzinotas, Antonis

    2005-05-01

    We isolated 28 strains of 'Spumella-like' flagellates from different freshwater and soil habitats in Austria, People's Republic of China, Nepal, New Zealand, Uganda, Kenya, Tanzania and Hawaii by use of a modified filtration-acclimatization method. 'Spumella-like' flagellates were found in all of the samples and were often among the dominant bacterivorous flagellates in the respective environments. The small subunit ribosomal RNA (SSU rRNA) gene sequence of the isolates was determined and aligned with previously published sequences of members belonging to the Chrysophyceae sensu stricto. Phylogenetic analysis of the 28 new sequences confirmed their position within the Chrysophyceae sensu stricto and positioned them within different clades. Most of the sequences grouped within clade C and formed several subclusters separated from each other by green taxa including flagellates belonging to Ochromonas, Dinobryon, Poterioochromonas and others. All soil isolates clustered together (subcluster C1) with the soil strain Spumella elongata and the undescribed soil strain 'Spumella danica'. Aquatic isolates were affiliated with at least two branches (C2 and C3). Sequence similarity to the closest related member of the Chrysophyceae ranged between 92% and 99.6%, sequence divergence among the 'Spumella-like' flagellates was as high as 10%. We conclude that (i) the 'Spumella-like' flagellates are a diverse group both in terms of sequence dissimilarity between isolates and in terms of the number of genotypes, (ii) Spumella and Ochromonas are polyphyletic, and (iii) based on the SSU rRNA gene no biogeographical restriction of certain branches could be observed even though different ecotypes may be represented by the same genotype.

  13. Flagellate Predation on a Bacterial Model Community: Interplay of Size-Selective Grazing, Specific Bacterial Cell Size, and Bacterial Community Composition

    PubMed Central

    Hahn, Martin W.; Höfle, Manfred G.

    1999-01-01

    The influence of grazing by the bacterivorous nanoflagellate Ochromonas sp. strain DS on the taxonomic and morphological structures of a complex bacterial community was studied in one-stage chemostat experiments. A bacterial community, consisting of at least 30 different strains, was fed with a complex carbon source under conditions of low growth rate (0.5 day−1 when nongrazed) and low substrate concentration (9 mg liter−1). Before and after the introduction of the predator, the bacterial community composition was studied by in situ techniques (immunofluorescence microscopy and fluorescent in situ hybridization), as well as by cultivation on agar media. The cell sizes of nonspecifically stained and immunofluorescently labeled bacteria were measured by image analysis. Grazing by the flagellate caused a bidirectional change in the morphological structure of the community. Medium-size bacterial cells, which dominated the nongrazed community, were largely replaced by smaller cells, as well as by cells contained in large multicellular flocs. Cell morphological changes were combined with community taxonomic changes. After introduction of the flagellate, the dominating strains with medium-size cells were largely replaced by single-celled strains with smaller cells on the one hand and, on the other hand, by Pseudomonas sp. strain MWH1, which formed the large, floc-like forms. We assume that size-selective grazing was the major force controlling both the morphological and the taxonomic structures of the model community. PMID:10543797

  14. Widespread occurrence of norspermidine and norspermine in eukaryotic algae.

    PubMed

    Hamana, K; Matsuzaki, S

    1982-04-01

    Seven phyla of eukaryotic algae were analyzed to determine their contents of diamines and polyamines. The algae examined included Rhodophyta, Pyrrophyta, Chrysophyta, Phaeophyta, Euglenophyta, Chlorophyta, and Charophyta. Both putrescine and spermidine were detected in all the algae studied, while appreciable amounts of spermine were detected only in a few species of algae. 1,3-Diaminopropane, norspermidine, and norspermine, which are chemical analogs of putrescine, spermidine, and spermine, respectively, were widely distributed in various species of algae. There was no parallelism between the distribution patterns of putrescine derivatives and those of 1,3-diaminopropane derivatives. Cadaverine and agmatine were detected in multicellular marine algae. Homospermidine was detected sporadically in some algae. The biological and phylogenetical significance of polyamines in these lower eukaryotes is discussed.

  15. Sulfated polysaccharides as bioactive agents from marine algae.

    PubMed

    Ngo, Dai-Hung; Kim, Se-Kwon

    2013-11-01

    Recently, much attention has been paid by consumers toward natural bioactive compounds as functional ingredients in nutraceuticals. Marine algae are considered as valuable sources of structurally diverse bioactive compounds. Marine algae are rich in sulfated polysaccharides (SPs) such as carrageenans in red algae, fucoidans in brown algae and ulvans in green algae. These SPs exhibit many health beneficial nutraceutical effects such as antioxidant, anti-allergic, anti-human immunodeficiency virus, anticancer and anticoagulant activities. Therefore, marine algae derived SPs have great potential to be further developed as medicinal food products or nutraceuticals in the food industry. This contribution presents an overview of nutraceutical effects and potential health benefits of SPs derived from marine algae.

  16. Photooxidative Death in Blue-Green Algae

    PubMed Central

    Abeliovich, A.; Shilo, M.

    1972-01-01

    When incubated in the light under 100% oxygen, wild-type blue-green algae (Anacystis nidulans, Synechococcus cedrorum) die out rapidly at temperatures of 4 to 15 C, and at 35 C (or at 26 C in the case of S. cedrorum) in the absence of CO2. Photosynthesis is impaired in these cells long before they die. Blocking of photosystem II at high temperatures in the presence of CO2 sensitizes the algae to photooxidative death. Photooxidative death and bleaching of photosynthetic pigments are separable phenomena. Photooxidative conditions were demonstrated in Israeli fish ponds using A. nidulans as the test organism during dense summer blooms, when dissolved CO2 is low, and in winter, when water temperatures generally drop below 15 C. This finding suggests that photooxidative death may be responsible for the sudden decomposition of blue-green blooms in summer, and may be a factor in the absence of blue-green blooms in winter. PMID:4626540

  17. Phycobilisomes in Blue-Green Algae

    PubMed Central

    Wildman, Ruth B.; Bowen, C. C.

    1974-01-01

    Fifteen species of freshwater blue-green algae, including unicellular, filamentous, and colonial forms, were subjected to a variety of fixatives, fixation conditions, and stains for comparison of the preservation of phycobilisomes. Absorption spectra of the corresponding in vivo and released photosynthetic pigments, in 10 of the species that were maintained in culture, demonstrated the presence of phycocyanin in all 10 species and phycoerythrin in only 2 of them. Spectroscope and electron microscope evidence was obtained for localization of phycobiliproteins in phycobilisomes of Nostoc muscorum. Phycobilisomes were observed in all species examined in situ, strenghening the hypothesis that phycobilisomes are common to all phycobiliprotein-containing photosynthetic blue-green algae. Images PMID:4204443

  18. Toxicity of chlorinated benzenes to marine algae

    NASA Astrophysics Data System (ADS)

    Ma, Yan-Jun; Wang, Xiu-Lin; Yu, Wei-Jun; Zhang, Li-Jun; Sun, Han-Zhang

    1997-12-01

    Growth of Chlorella marine, Nannochloropsis oculata, Pyramidomonas sp., Platymonas subcordiformis and Phaeodactylum tricornutum exposed to monochlorobenzene (MCB), 1,2-dichlorobenzene (1,2-DCB), 1, 2, 3, 4-tetrachlorobenzene (1, 2, 3, 4-TeCB) and pentachlorobenzene (PeCB) was tested. Tests of 72 h- EC 50 values showed that the toxicity ranged in the order: MCB<1,2-DCB<1,2,3,4-TeCBalgae was almost in the order: Pyramidomonas sp. < Platymonas subcordiformis < Nannochloropsis oculata < Chlorella marine < Phaeodactylum tricomutum. Study of the QSAR (Quantitative Structure-Activity Relationship) between K OW and toxicity of CBs to marine algae showed good relationships between -log EC 50 and log K OW.

  19. Bioconcentration of tetrachlorobenzene in marine algae

    NASA Astrophysics Data System (ADS)

    Wang, Xiu-Lin; Ma, Yan-Jun; Cheng, Gang; Yu, Wei-Jun; Zhang, Li-Jun

    1997-09-01

    Bioconcentration of tetrachlorobenzene (TeCB) in Chlorella marine, Nannochloropsis oculata, Pyramidomonas sp., Platymonas subcordiformis, and Phaeodactylum tricornutum; and toxicity of TeCB to the marine algae were tested. Values of bioconcentration potential parameters, including uptake rate constant k 1, elimination rate constant k 2 and bioconcentration factor BCF, were obtained not only from the time course of TeCB uptake by the marine algae by using a bioconcentration model, but also from the acute toxicity test data for percent inhibition PI(%)˜exposure concentration of TeCB-time by using a combined bioconcentration and probability model. The results showed good relationship between k 1(TOXIC) and k 1(UPTAKE) and k 2(TOXIC), k 2(UPTAKE), and BCF D(IOXIC) and BCF D(UPTAKE). Especially, the values of BCF D(TOXIC) were well consistent with those of BCF D(UPTAKE).

  20. Biofuels from algae: challenges and potential

    PubMed Central

    Hannon, Michael; Gimpel, Javier; Tran, Miller; Rasala, Beth; Mayfield, Stephen

    2011-01-01

    Algae biofuels may provide a viable alternative to fossil fuels; however, this technology must overcome a number of hurdles before it can compete in the fuel market and be broadly deployed. These challenges include strain identification and improvement, both in terms of oil productivity and crop protection, nutrient and resource allocation and use, and the production of co-products to improve the economics of the entire system. Although there is much excitement about the potential of algae biofuels, much work is still required in the field. In this article, we attempt to elucidate the major challenges to economic algal biofuels at scale, and improve the focus of the scientific community to address these challenges and move algal biofuels from promise to reality. PMID:21833344

  1. Nitrogenous wastewater treatment by activated algae

    SciTech Connect

    Gupta, S.K.

    1985-02-01

    A biological treatability study by activated algae process was performed with synthetic wastewater containing a high concentration of nitrogen. It was found that the wastewater could be processed at all nitrogen removal rates. The yield coefficient and decay coefficient for heterotrophic bacteria were 0.06 (COD basis) and 0.019 day/sup -1/ (COD bases) respectively. The yield coefficient and decay coefficient for nitrifiers were 0.06 and 0.02 day/sup -1/ respectively. NH/sup +//sub 4/-N seemed to inhibit bacteriological growth as the yield coefficients values were significantly lower. Nitrification was observed at all the nitrogen loadings. Diffusion of NH/sub 3/ into the atmosphere was the dominant mechanism of nitrogen removal. The results demonstrated a symbiotic relationship between algae and bacteria.

  2. Fermentation metabolism and its evolution in algae

    PubMed Central

    Catalanotti, Claudia; Yang, Wenqiang; Posewitz, Matthew C.; Grossman, Arthur R.

    2013-01-01

    Fermentation or anoxic metabolism allows unicellular organisms to colonize environments that become anoxic. Free-living unicellular algae capable of a photoautotrophic lifestyle can also use a range of metabolic circuitry associated with different branches of fermentation metabolism. While algae that perform mixed-acid fermentation are widespread, the use of anaerobic respiration is more typical of eukaryotic heterotrophs. The occurrence of a core set of fermentation pathways among the algae provides insights into the evolutionary origins of these pathways, which were likely derived from a common ancestral eukaryote. Based on genomic, transcriptomic, and biochemical studies, anaerobic energy metabolism has been examined in more detail in Chlamydomonas reinhardtii (Chlamydomonas) than in any other photosynthetic protist. This green alga is metabolically flexible and can sustain energy generation and maintain cellular redox balance under a variety of different environmental conditions. Fermentation metabolism in Chlamydomonas appears to be highly controlled, and the flexible use of the different branches of fermentation metabolism has been demonstrated in studies of various metabolic mutants. Additionally, when Chlamydomonas ferments polysaccharides, it has the ability to eliminate part of the reductant (to sustain glycolysis) through the production of H2, a molecule that can be developed as a source of renewable energy. To date, little is known about the specific role(s) of the different branches of fermentation metabolism, how photosynthetic eukaryotes sense changes in environmental O2 levels, and the mechanisms involved in controlling these responses, at both the transcriptional and post-transcriptional levels. In this review, we focus on fermentation metabolism in Chlamydomonas and other protists, with only a brief discussion of plant fermentation when relevant, since it is thoroughly discussed in other articles in this volume. PMID:23734158

  3. Selenium Uptake and Volatilization by Marine Algae

    NASA Astrophysics Data System (ADS)

    Luxem, Katja E.; Vriens, Bas; Wagner, Bettina; Behra, Renata; Winkel, Lenny H. E.

    2015-04-01

    Selenium (Se) is an essential trace nutrient for humans. An estimated one half to one billion people worldwide suffer from Se deficiency, which is due to low concentrations and bioavailability of Se in soils where crops are grown. It has been hypothesized that more than half of the atmospheric Se deposition to soils is derived from the marine system, where microorganisms methylate and volatilize Se. Based on model results from the late 1980s, the atmospheric flux of these biogenic volatile Se compounds is around 9 Gt/year, with two thirds coming from the marine biosphere. Algae, fungi, and bacteria are known to methylate Se. Although algal Se uptake, metabolism, and methylation influence the speciation and bioavailability of Se in the oceans, these processes have not been quantified under environmentally relevant conditions and are likely to differ among organisms. Therefore, we are investigating the uptake and methylation of the two main inorganic Se species (selenate and selenite) by three globally relevant microalgae: Phaeocystis globosa, the coccolithophorid Emiliania huxleyi, and the diatom Thalassiosira oceanica. Selenium uptake and methylation were quantified in a batch experiment, where parallel gas-tight microcosms in a climate chamber were coupled to a gas-trapping system. For E. huxleyi, selenite uptake was strongly dependent on aqueous phosphate concentrations, which agrees with prior evidence that selenite uptake by phosphate transporters is a significant Se source for marine algae. Selenate uptake was much lower than selenite uptake. The most important volatile Se compounds produced were dimethyl selenide, dimethyl diselenide, and dimethyl selenyl sulfide. Production rates of volatile Se species were larger with increasing intracellular Se concentration and in the decline phase of the alga. Similar experiments are being carried out with P. globosa and T. oceanica. Our results indicate that marine algae are important for the global cycling of Se

  4. Fermentation metabolism and its evolution in algae.

    PubMed

    Catalanotti, Claudia; Yang, Wenqiang; Posewitz, Matthew C; Grossman, Arthur R

    2013-01-01

    Fermentation or anoxic metabolism allows unicellular organisms to colonize environments that become anoxic. Free-living unicellular algae capable of a photoautotrophic lifestyle can also use a range of metabolic circuitry associated with different branches of fermentation metabolism. While algae that perform mixed-acid fermentation are widespread, the use of anaerobic respiration is more typical of eukaryotic heterotrophs. The occurrence of a core set of fermentation pathways among the algae provides insights into the evolutionary origins of these pathways, which were likely derived from a common ancestral eukaryote. Based on genomic, transcriptomic, and biochemical studies, anaerobic energy metabolism has been examined in more detail in Chlamydomonas reinhardtii (Chlamydomonas) than in any other photosynthetic protist. This green alga is metabolically flexible and can sustain energy generation and maintain cellular redox balance under a variety of different environmental conditions. Fermentation metabolism in Chlamydomonas appears to be highly controlled, and the flexible use of the different branches of fermentation metabolism has been demonstrated in studies of various metabolic mutants. Additionally, when Chlamydomonas ferments polysaccharides, it has the ability to eliminate part of the reductant (to sustain glycolysis) through the production of H2, a molecule that can be developed as a source of renewable energy. To date, little is known about the specific role(s) of the different branches of fermentation metabolism, how photosynthetic eukaryotes sense changes in environmental O2 levels, and the mechanisms involved in controlling these responses, at both the transcriptional and post-transcriptional levels. In this review, we focus on fermentation metabolism in Chlamydomonas and other protists, with only a brief discussion of plant fermentation when relevant, since it is thoroughly discussed in other articles in this volume.

  5. Algae-Derived Dietary Ingredients Nourish Animals

    NASA Technical Reports Server (NTRS)

    2015-01-01

    In the 1980s, Columbia, Maryland-based Martek Biosciences Corporation worked with Ames Research Center to pioneer the use of microalgae as a source of essential omega-3 fatty acids, work that led the company to develop its highly successful Formulaid product. Now the Nutritional Products Division of Royal DSM, the company also manufactures DHAgold, a nutritional supplement for pets, livestock and farm-raised fish that uses algae to deliver docosahexaenoic acid (DHA).

  6. Antibody Production in Plants and Green Algae.

    PubMed

    Yusibov, Vidadi; Kushnir, Natasha; Streatfield, Stephen J

    2016-04-29

    Monoclonal antibodies (mAbs) have a wide range of modern applications, including research, diagnostic, therapeutic, and industrial uses. Market demand for mAbs is high and continues to grow. Although mammalian systems, which currently dominate the biomanufacturing industry, produce effective and safe recombinant mAbs, they have a limited manufacturing capacity and high costs. Bacteria, yeast, and insect cell systems are highly scalable and cost effective but vary in their ability to produce appropriate posttranslationally modified mAbs. Plants and green algae are emerging as promising production platforms because of their time and cost efficiencies, scalability, lack of mammalian pathogens, and eukaryotic posttranslational protein modification machinery. So far, plant- and algae-derived mAbs have been produced predominantly as candidate therapeutics for infectious diseases and cancer. These candidates have been extensively evaluated in animal models, and some have shown efficacy in clinical trials. Here, we review ongoing efforts to advance the production of mAbs in plants and algae. PMID:26905655

  7. Antibody Production in Plants and Green Algae.

    PubMed

    Yusibov, Vidadi; Kushnir, Natasha; Streatfield, Stephen J

    2016-04-29

    Monoclonal antibodies (mAbs) have a wide range of modern applications, including research, diagnostic, therapeutic, and industrial uses. Market demand for mAbs is high and continues to grow. Although mammalian systems, which currently dominate the biomanufacturing industry, produce effective and safe recombinant mAbs, they have a limited manufacturing capacity and high costs. Bacteria, yeast, and insect cell systems are highly scalable and cost effective but vary in their ability to produce appropriate posttranslationally modified mAbs. Plants and green algae are emerging as promising production platforms because of their time and cost efficiencies, scalability, lack of mammalian pathogens, and eukaryotic posttranslational protein modification machinery. So far, plant- and algae-derived mAbs have been produced predominantly as candidate therapeutics for infectious diseases and cancer. These candidates have been extensively evaluated in animal models, and some have shown efficacy in clinical trials. Here, we review ongoing efforts to advance the production of mAbs in plants and algae.

  8. New records of marine algae in Vietnam

    NASA Astrophysics Data System (ADS)

    Le Hau, Nhu; Ly, Bui Minh; Van Huynh, Tran; Trung, Vo Thanh

    2015-06-01

    In May, 2013, a scientific expedition was organized by the Vietnam Academy of Science and Technology (VAST) and the Far Eastern Branch of the Russian Academy of Sciences (FEBRAS) through the frame of the VAST-FEBRAS International Collaboration Program. The expedition went along the coast of Vietnam from Quang Ninh to Kien Giang. The objective was to collect natural resources to investigate the biological and biochemical diversity of the territorial waters of Vietnam. Among the collected algae, six taxa are new records for the Vietnam algal flora. They are the red algae Titanophora pikeana (Dickie) Feldmann from Cu Lao Xanh Island, Laurencia natalensis Kylin from Tho Chu Island, Coelothrix irregularis (Harvey) Børgesen from Con Dao Island, the green algae Caulerpa oligophylla Montagne, Caulerpa andamanensis (W.R. Taylor) Draisma, Prudhomme et Sauvage from Phu Quy Island, and Caulerpa falcifolia Harvey & Bailey from Ly Son Island. The seaweed flora of Vietnam now counts 833 marine algal taxa, including 415 Rhodophyta, 147 Phaeophyceae, 183 Chlorophyta, and 88 Cyanobacteria.

  9. Environmental life cycle comparison of algae to other bioenergy feedstocks.

    PubMed

    Clarens, Andres F; Resurreccion, Eleazer P; White, Mark A; Colosi, Lisa M

    2010-03-01

    Algae are an attractive source of biomass energy since they do not compete with food crops and have higher energy yields per area than terrestrial crops. In spite of these advantages, algae cultivation has not yet been compared with conventional crops from a life cycle perspective. In this work, the impacts associated with algae production were determined using a stochastic life cycle model and compared with switchgrass, canola, and corn farming. The results indicate that these conventional crops have lower environmental impacts than algae in energy use, greenhouse gas emissions, and water regardless of cultivation location. Only in total land use and eutrophication potential do algae perform favorably. The large environmental footprint of algae cultivation is driven predominantly by upstream impacts, such as the demand for CO(2) and fertilizer. To reduce these impacts, flue gas and, to a greater extent, wastewater could be used to offset most of the environmental burdens associated with algae. To demonstrate the benefits of algae production coupled with wastewater treatment, the model was expanded to include three different municipal wastewater effluents as sources of nitrogen and phosphorus. Each provided a significant reduction in the burdens of algae cultivation, and the use of source-separated urine was found to make algae more environmentally beneficial than the terrestrial crops. PMID:20085253

  10. Electro-coagulation-flotation process for algae removal.

    PubMed

    Gao, Shanshan; Yang, Jixian; Tian, Jiayu; Ma, Fang; Tu, Gang; Du, Maoan

    2010-05-15

    Algae in surface water have been a long-term issue all over the world, due to their adverse influence on drinking water treatment process as well as drinking water quality. The algae removal by electro-coagulation-flotation (ECF) technology was investigated in this paper. The results indicated that aluminum was an excellent electrode material for algae removal as compared with iron. The optimal parameters determined were: current density=1 mA/cm(2), pH=4-7, water temperature=18-36 degrees C, algae density=0.55 x 10(9)-1.55 x 10(9) cells/L. Under the optimal conditions, 100% of algae removal was achieved with the energy consumption as low as 0.4 kWh/m(3). The ECF performed well in acid and neutral conditions. At low initial pH of 4-7, the cell density of algae was effectively removed in the ECF, mainly through the charge neutralization mechanism; while the algae removal worsened when the pH increased (7-10), and the main mechanism shifted to sweeping flocculation and enmeshment. The mechanisms for algae removal at different pH were also confirmed by atomic force microscopy (AFM) analysis. Furthermore, initial cell density and water temperature could also influence the algae removal. Overall, the results indicated that the ECF technology was effective for algae removal, from both the technical and economical points of view. PMID:20042280

  11. Electro-coagulation-flotation process for algae removal.

    PubMed

    Gao, Shanshan; Yang, Jixian; Tian, Jiayu; Ma, Fang; Tu, Gang; Du, Maoan

    2010-05-15

    Algae in surface water have been a long-term issue all over the world, due to their adverse influence on drinking water treatment process as well as drinking water quality. The algae removal by electro-coagulation-flotation (ECF) technology was investigated in this paper. The results indicated that aluminum was an excellent electrode material for algae removal as compared with iron. The optimal parameters determined were: current density=1 mA/cm(2), pH=4-7, water temperature=18-36 degrees C, algae density=0.55 x 10(9)-1.55 x 10(9) cells/L. Under the optimal conditions, 100% of algae removal was achieved with the energy consumption as low as 0.4 kWh/m(3). The ECF performed well in acid and neutral conditions. At low initial pH of 4-7, the cell density of algae was effectively removed in the ECF, mainly through the charge neutralization mechanism; while the algae removal worsened when the pH increased (7-10), and the main mechanism shifted to sweeping flocculation and enmeshment. The mechanisms for algae removal at different pH were also confirmed by atomic force microscopy (AFM) analysis. Furthermore, initial cell density and water temperature could also influence the algae removal. Overall, the results indicated that the ECF technology was effective for algae removal, from both the technical and economical points of view.

  12. Extra-chromosomal DNA maintenance in Bacillus subtilis, dependence on flagellation factor FliF and moonlighting mediator EdmS.

    PubMed

    Hakumai, Yuichi; Shimomoto, Kouko; Ashiuchi, Makoto

    2015-05-15

    Extra-chromosomal DNA maintenance (EDM) as an important process in the propagation and genetic engineering of microbes. Bacillus subtilis EdmS (formerly PgsE), a protein comprising 55 amino acids, is a mediator of the EDM process. In this study, the effect of mutation of global regulators on B. subtilis EDM was examined. Mutation of the swrA gene abolished EdmS-mediated EDM. It is known that swrA predominantly regulates expression of the fla/che operon in B. subtilis. We therefore performed EDM analysis using fla/che-deletion mutants and identified an EDM-mediated EDM cooperator in the flgB-fliL region. Further genetic investigation identified the flagellation factor FliF is a crucial EDM cooperator. To our knowledge, this is the first observation of the moonlighting function of FliF in DNA maintenance.

  13. Hydrogenases in green algae: do they save the algae's life and solve our energy problems?

    PubMed

    Happe, Thomas; Hemschemeier, Anja; Winkler, Martin; Kaminski, Annette

    2002-06-01

    Green algae are the only known eukaryotes with both oxygenic photosynthesis and a hydrogen metabolism. Recent physiological and genetic discoveries indicate a close connection between these metabolic pathways. The anaerobically inducible hydA genes of algae encode a special type of highly active [Fe]-hydrogenase. Electrons from reducing equivalents generated during fermentation enter the photosynthetic electron transport chain via the plastoquinone pool. They are transferred to the hydrogenase by photosystem I and ferredoxin. Thus, the [Fe]-hydrogenase is an electron 'valve' that enables the algae to survive under anaerobic conditions. During sulfur deprivation, illuminated algal cultures evolve large quantities of hydrogen gas, and this promises to be an alternative future energy source. PMID:12049920

  14. A bead-spring model for running and tumbling of flagellated swimmers: detailed predictions compared to experimental data for E. coli.

    PubMed

    Kong, Miqiu; Wu, Yan; Li, Guangxian; Larson, Ronald G

    2015-02-28

    To study the swimming of the multi-flagellated bacterium Escherichia coli, we deploy a bead-spring hydrodynamic model (Watari and Larson 2010), whose body and flagellar geometry, motor torques, and motor reversals are adjusted to match the experimental observations of the Berg group (Turner et al. 2000; Darnton et al. 2007) during both running and tumbling of the bacterium. In this model, hydrodynamic interactions, which drive swimming, flagellar bundling, and unbundling during swimming and tumbling, are imposed by treating the beads as Stokeslets, imposing torques and counter-torques on the body and flagellum at the flexible joint connecting them to represent the action of motor, and using the Rotne-Prager tensor to model their hydrodynamic interactions with other beads. We explore the behavior of coarse-grained (60-bead) and refined (120-bead) versions of the model, and show that predictions of running speed, helical and body rotation rates, body wobble rates and angles, average tumbling angles, range of tumbling angles, and flagellar re-bundling times are in good agreement with experimental observations by Berg and coworkers. We find that variation in tumbling angle arises from variation in flagellar number and location on the bacterial body, variations in polymorphic transitions of the filaments, and especially from variations in the duration of the tumbling time, which is roughly linearly correlated with tumbling time up to tumbling angles of around 40-50° and more weakly thereafter. The accuracy of the model suggests its usefulness for future studies of swimming of other flagellated swimmers, for predictions of collective phenomena, and for tuning parameters of coarser-grained swimmer models to achieve greater realism.

  15. Microplate Technique for Determining Accumulation of Metals by Algae

    PubMed Central

    Hassett, James M.; Jennett, J. Charles; Smith, James E.

    1981-01-01

    A microplate technique was developed to determine the conditions under which pure cultures of algae removed heavy metals from aqueous solutions. Variables investigated included algal species and strain, culture age (11 and 44 days), metal (mercury, lead, cadmium, and zinc), pH, effects of different buffer solutions, and time of exposure. Plastic, U-bottomed microtiter plates were used in conjunction with heavy metal radionuclides to determine concentration factors for metal-alga combinations. The technique developed was rapid, statistically reliable, and economical of materials and cells. Results (expressed as concentration factors) were in reasonably good agreement with literature values. All species of algae studied removed mercury from solution. Green algae proved better at accumulating cadmium than did blue-green algae. No alga studied removed zinc, perhaps because cells were maintained in the dark during the labeling period. Chlamydomonas sp. proved superior in ability to remove lead from solution. PMID:16345764

  16. Exploring the potential of algae/bacteria interactions.

    PubMed

    Kouzuma, Atsushi; Watanabe, Kazuya

    2015-06-01

    Algae are primary producers in aquatic ecosystems, where heterotrophic bacteria grow on organics produced by algae and recycle nutrients. Ecological studies have identified the co-occurrence of particular species of algae and bacteria, suggesting the presence of their specific interactions. Algae/bacteria interactions are categorized into nutrient exchange, signal transduction and gene transfer. Studies have examined how these interactions shape aquatic communities and influence geochemical cycles in the natural environment. In parallel, efforts have been made to exploit algae for biotechnology processes, such as water treatment and bioenergy production, where bacteria influence algal activities in various ways. We suggest that better understanding of mechanisms underlying algae/bacteria interactions will facilitate the development of more efficient and/or as-yet-unexploited biotechnology processes.

  17. Method and apparatus for iterative lysis and extraction of algae

    SciTech Connect

    Chew, Geoffrey; Boggs, Tabitha; Dykes, Jr., H. Waite H.; Doherty, Stephen J.

    2015-12-01

    A method and system for processing algae involves the use of an ionic liquid-containing clarified cell lysate to lyse algae cells. The resulting crude cell lysate may be clarified and subsequently used to lyse algae cells. The process may be repeated a number of times before a clarified lysate is separated into lipid and aqueous phases for further processing and/or purification of desired products.

  18. Bromophenols from marine algae with potential anti-diabetic activities

    NASA Astrophysics Data System (ADS)

    Lin, Xiukun; Liu, Ming

    2012-12-01

    Marine algae contain various bromophenols with a variety of biological activities, including antimicrobial, anticancer, and anti-diabetic effects. Here, we briefly review the recent progress in researches on the biomaterials from marine algae, emphasizing the relationship between the structure and the potential anti-diabetic applications. Bromophenols from marine algae display their hyperglycemic effects by inhibiting the activities of protein tyrosine phosphatase 1B, α-glucosidase, as well as other mechanisms.

  19. Algae to Bio-Crude in Less Than 60 Minutes

    ScienceCinema

    Elliott, Doug

    2016-07-12

    Engineers have created a chemical process that produces useful crude oil just minutes after engineers pour in harvested algae -- a verdant green paste with the consistency of pea soup. The PNNL team combined several chemical steps into one continuous process that starts with an algae slurry that contains as much as 80 to 90 percent water. Most current processes require the algae to be dried -- an expensive process that takes a lot of energy. The research has been licensed by Genifuel Corp.

  20. Method for producing hydrogen and oxygen by use of algae

    DOEpatents

    Greenbaum, Elias

    1984-01-01

    Efficiency of process for producing H.sub.2 by subjecting algae in an aqueous phase to light irradiation is increased by culturing algae which has been bleached during a first period of irradiation in a culture medium in an aerobic atmosphere until it has regained color and then subjecting this algae to a second period of irradiation wherein hydrogen is produced at an enhanced rate.

  1. Algae to Bio-Crude in Less Than 60 Minutes

    SciTech Connect

    Elliott, Doug

    2013-12-17

    Engineers have created a chemical process that produces useful crude oil just minutes after engineers pour in harvested algae -- a verdant green paste with the consistency of pea soup. The PNNL team combined several chemical steps into one continuous process that starts with an algae slurry that contains as much as 80 to 90 percent water. Most current processes require the algae to be dried -- an expensive process that takes a lot of energy. The research has been licensed by Genifuel Corp.

  2. Method for producing hydrogen and oxygen by use of algae

    DOEpatents

    Greenbaum, E.

    1982-06-16

    Efficiency of process for producing H/sub 2/ by subjecting algae in an aqueous phase to light irradiation is increased by culturing algae which has been bleached during a first period of irradiation in a culture medium in an aerobic atmosphere until it has regained color and then subjecting this algae to a second period of irradiation wherein hydrogen is produced at an enhanced rate.

  3. Overall Energy Considerations for Algae Species Comparison and Selection in Algae-to-Fuels Processes

    SciTech Connect

    Link, D.; Kail, B.; Curtis, W.; Tuerk,A.

    2011-01-01

    The controlled growth of microalgae as a feedstock for alternative transportation fuel continues to receive much attention. Microalgae have the characteristics of rapid growth rate, high oil (lipid) content, and ability to be grown in unconventional scenarios. Algae have also been touted as beneficial for CO{sub 2} reuse, as algae can be grown using CO{sub 2} emissions from fossil-based energy generation. Moreover, algae does not compete in the food chain, lessening the 'food versus fuel' debate. Most often, it is assumed that either rapid production rate or high oii content should be the primary factor in algae selection for algae-to-fuels production systems. However, many important characteristics of algae growth and lipid production must be considered for species selection, growth condition, and scale-up. Under light limited, high density, photoautotrophic conditions, the inherent growth rate of an organism does not affect biomass productivity, carbon fixation rate, and energy fixation rate. However, the oil productivity is organism dependent, due to physiological differences in how the organisms allocate captured photons for growth and oil production and due to the differing conditions under which organisms accumulate oils. Therefore, many different factors must be considered when assessing the overall energy efficiency of fuel production for a given algae species. Two species, Chlorella vulgaris and Botryococcus braunii, are popular choices when discussing algae-to-fuels systems. Chlorella is a very robust species, often outcompeting other species in mixed-culture systems, and produces a lipid that is composed primarily of free fatty acids and glycerides. Botryococcus is regarded as a slower growing species, and the lipid that it produces is characterized by high hydrocarbon content, primarily C28-C34 botryococcenes. The difference in growth rates is often considered to be an advantage oiChlorella. However, the total energy captured by each algal species in

  4. Triclosan (TCS) and Triclocarban (TCC) cause lifespan reduction and reproductive impairment through oxidative stress-mediated expression of the defensome in the monogonont rotifer (Brachionus koreanus).

    PubMed

    Han, Jeonghoon; Won, Eun-Ji; Hwang, Un-Ki; Kim, Il-Chan; Yim, Joung Han; Lee, Jae-Seong

    2016-01-01

    Triclosan (TCS) and Triclocarban (TCC) are used as antimicrobial agents and have been widely dispersed and detected in the marine environment. However, the toxicities of TCS and TCC have been poorly investigated in marine invertebrates. In this study, the effects of TCS and TCC on mortality, population growth, lifespan, and fecundity were examined in the monogonont rotifer (Brachionus koreanus) using cellular ROS levels, GST enzymatic activity, and gene expression of defensomes. The median lethal concentration (LC50) of TCS (393.1μg/L) and TCC (388.1μg/L) was also determined in the same species. In TCS- and TCC-exposed B. koreanus, growth retardation and reduced fecundity were observed and were shown to have a potentially deleterious effect on the life cycle of B. koreanus. In addition, time-dependent increases in ROS content (%) and GST enzymatic activity were shown in response to TCS and TCC exposure. Additionally, transcript levels of detoxification proteins (e.g., CYPs), antioxidant proteins (e.g., GST-sigma, Cu/ZnSOD, CAT), and heat shock proteins (Hsps) were modulated in response to TCS and TCC exposure over a 24h period. Our results indicate that TCS and TCC induce oxidative stress and transcriptional regulation of detoxification, antioxidant, and heat shock proteins, resulting in changes in lifespan and fecundity.

  5. Expression pattern of entire cytochrome P450 genes and response of defensomes in the benzo[a]pyrene-exposed monogonont rotifer Brachionus koreanus.

    PubMed

    Kim, Ryeo-Ok; Kim, Bo-Mi; Jeong, Chang-Bum; Nelson, David R; Lee, Jae-Seong; Rhee, Jae-Sung

    2013-12-01

    Cytochrome P450 (CYP) proteins are involved in the first line of detoxification mechanism against diverse polycyclic aromatic hydrocarbons (PAHs) including benzo[a]pyrene (B[a]P). In aquatic invertebrates, there is still a lack of knowledge on the CYP genes involved in the molecular response to B[a]P exposure due to limited gene information. In this study, we cloned the entire 25 CYP genes in the monogonont rotifer Brachionus koreanus with the aid of next generation sequencing (NGS) technologies and analyzed their transcript profiles with a real-time RT-PCR array to better understand B[a]P-triggered molecular response over different time courses. As a result, B[a]P exposure induced CYP2/3-involved detoxification mechanisms and defensome, including phase II detoxification and antioxidant systems with a modulation of the chaperone heat shock protein (hsp) expression but did not change expression of other CYP clans in B. koreanus . Therefore, we found that B[a]P induced a strong detoxification mechanism to overcome detrimental effects of B[a]P associated with B[a]P-induced growth retardation as a trade-off in fitness costs. Also, this approach revealed that the entire CYP profiling can be a way of providing a better understanding on the mode of action of B[a]P in B. koreanus with respect to molecular defense metabolism.

  6. Triclosan (TCS) and Triclocarban (TCC) cause lifespan reduction and reproductive impairment through oxidative stress-mediated expression of the defensome in the monogonont rotifer (Brachionus koreanus).

    PubMed

    Han, Jeonghoon; Won, Eun-Ji; Hwang, Un-Ki; Kim, Il-Chan; Yim, Joung Han; Lee, Jae-Seong

    2016-01-01

    Triclosan (TCS) and Triclocarban (TCC) are used as antimicrobial agents and have been widely dispersed and detected in the marine environment. However, the toxicities of TCS and TCC have been poorly investigated in marine invertebrates. In this study, the effects of TCS and TCC on mortality, population growth, lifespan, and fecundity were examined in the monogonont rotifer (Brachionus koreanus) using cellular ROS levels, GST enzymatic activity, and gene expression of defensomes. The median lethal concentration (LC50) of TCS (393.1μg/L) and TCC (388.1μg/L) was also determined in the same species. In TCS- and TCC-exposed B. koreanus, growth retardation and reduced fecundity were observed and were shown to have a potentially deleterious effect on the life cycle of B. koreanus. In addition, time-dependent increases in ROS content (%) and GST enzymatic activity were shown in response to TCS and TCC exposure. Additionally, transcript levels of detoxification proteins (e.g., CYPs), antioxidant proteins (e.g., GST-sigma, Cu/ZnSOD, CAT), and heat shock proteins (Hsps) were modulated in response to TCS and TCC exposure over a 24h period. Our results indicate that TCS and TCC induce oxidative stress and transcriptional regulation of detoxification, antioxidant, and heat shock proteins, resulting in changes in lifespan and fecundity. PMID:27067728

  7. Algae Bioreactor Using Submerged Enclosures with Semi-Permeable Membranes

    NASA Technical Reports Server (NTRS)

    Trent, Jonathan D (Inventor); Gormly, Sherwin J (Inventor); Embaye, Tsegereda N (Inventor); Delzeit, Lance D (Inventor); Flynn, Michael T (Inventor); Liggett, Travis A (Inventor); Buckwalter, Patrick W (Inventor); Baertsch, Robert (Inventor)

    2013-01-01

    Methods for producing hydrocarbons, including oil, by processing algae and/or other micro-organisms in an aquatic environment. Flexible bags (e.g., plastic) with CO.sub.2/O.sub.2 exchange membranes, suspended at a controllable depth in a first liquid (e.g., seawater), receive a second liquid (e.g., liquid effluent from a "dead zone") containing seeds for algae growth. The algae are cultivated and harvested in the bags, after most of the second liquid is removed by forward osmosis through liquid exchange membranes. The algae are removed and processed, and the bags are cleaned and reused.

  8. Method and apparatus for lysing and processing algae

    DOEpatents

    Chew, Geoffrey; Reich, Alton J.; Dykes, Jr., H. Waite H.; Di Salvo, Roberto

    2013-03-05

    Methods and apparatus for processing algae are described in which a hydrophilic ionic liquid is used to lyse algae cells at lower temperatures than existing algae processing methods. A salt or salt solution is used as a separation agent and to remove water from the ionic liquid, allowing the ionic liquid to be reused. The used salt may be dried or concentrated and reused. The relatively low lysis temperatures and recycling of the ionic liquid and salt reduce the environmental impact of the algae processing while providing biofuels and other useful products.

  9. Exploring the potential of using algae in cosmetics.

    PubMed

    Wang, Hui-Min David; Chen, Ching-Chun; Huynh, Pauline; Chang, Jo-Shu

    2015-05-01

    The applications of microalgae in cosmetic products have recently received more attention in the treatment of skin problems, such as aging, tanning and pigment disorders. There are also potential uses in the areas of anti-aging, skin-whitening, and pigmentation reduction products. While algae species have already been used in some cosmetic formulations, such as moisturizing and thickening agents, algae remain largely untapped as an asset in this industry due to an apparent lack of utility as a primary active ingredient. This review article focuses on integrating studies on algae pertinent to skin health and beauty, with the purpose of identifying serviceable algae functions in practical cosmetic uses.

  10. A technical evaluation of biodiesel from vegetable oils vs. algae. Will algae-derived biodiesel perform?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biodiesel, one of the most prominent renewable alternative fuels, can be derived from a variety of sources including vegetable oils, animal fats and used cooking oils as well as alternative sources such as algae. While issues such as land-use change, food vs. fuel, feedstock availability, and produc...

  11. [THE MICROSCOPIC ALGAE AS HUMAN PATHOGENS].

    PubMed

    Roman, Manuel Casal

    2014-01-01

    Some microscopic algae can cause different infectious diseases in humans, including skin, bone, and disseminated. These little-known emerging disease are more severe in immunocompromised patients. The confirmatory microbiological diagnosis must be done differential with yeast-like fungi that can be confused. Anti-fungal drugs and surgery, being quite frequent treatment failure have been used in the treatment. Given the increase of immunosuppression in the current medicine and new possibilities of microbiological diagnostics, it is logical that these diseases tend to increase, by which all physician should know them. PMID:27386675

  12. Factors affecting spore germination in algae - review.

    PubMed

    Agrawal, S C

    2009-01-01

    This review surveys whatever little is known on the influence of different environmental factors like light, temperature, nutrients, chemicals (such as plant hormones, vitamins, etc.), pH of the medium, biotic factors (such as algal extracellular substances, algal concentration, bacterial extracellular products, animal grazing and animal extracellular products), water movement, water stress, antibiotics, UV light, X-rays, gamma-rays, and pollution on the spore germination in algae. The work done on the dormancy of algal spores and on the role of vegetative cells in tolerating environmental stress is also incorporated. PMID:19826917

  13. [THE MICROSCOPIC ALGAE AS HUMAN PATHOGENS].

    PubMed

    Roman, Manuel Casal

    2014-01-01

    Some microscopic algae can cause different infectious diseases in humans, including skin, bone, and disseminated. These little-known emerging disease are more severe in immunocompromised patients. The confirmatory microbiological diagnosis must be done differential with yeast-like fungi that can be confused. Anti-fungal drugs and surgery, being quite frequent treatment failure have been used in the treatment. Given the increase of immunosuppression in the current medicine and new possibilities of microbiological diagnostics, it is logical that these diseases tend to increase, by which all physician should know them.

  14. Effect of petroleum hydrocarbons on algae

    SciTech Connect

    Bhadauria, S. ); Sengar, R.M.S. ); Mittal, S.; Bhattacharjee, S. )

    1992-01-01

    Algal species (65) were isolated from oil refinery effluent. Twenty-five of these species were cultured in Benecke's medium in a growth chamber, along with controls. Retardation in algal growth, inhibition in algal photosynthesis, and discoloration was observed in petroleum enriched medium. Few forms, viz. Cyclotella sp., Cosmarium sp., and Merismopedia sp. could not survive. The lag phase lengthened by several days and slope of exponential phase was also depressed. Chlamydomonas sp., Scenedesmus sp., Ankistrodesmus sp., Nitzschia sp. and Navicula sp. were comparatively susceptible to petroleum. Depression in carbon fixation, cell numbers, and total dry algal mass was noticeable, showing toxicity to both diatoms and green algae.

  15. Pheromones in marine algae: A technical approach

    NASA Astrophysics Data System (ADS)

    Gassmann, G.; Müller, D. G.; Fritz, P.

    1995-03-01

    It is now well known that many marine organisms use low-molecular volatile substances as signals, in order to coordinate activities between different individuals. The study of such pheromones requires the isolation and enrichment of the secretions from undisturbed living cells or organisms over extended periods of time. The Grob-Hersch extraction device, which we describe here, avoids adverse factors for the biological materials such as strong water currents, rising gas bubbles or chemical solvents. Furthermore, the formation of sea-water spray is greatly reduced. The application of this technique for the isolation of pheromones of marine algae and animals is described.

  16. How 5000 independent rowers coordinate their strokes in order to row into the sunlight: Phototaxis in the multicellular green alga Volvox

    PubMed Central

    2010-01-01

    Background The evolution of multicellular motile organisms from unicellular ancestors required the utilization of previously evolved tactic behavior in a multicellular context. Volvocine green algae are uniquely suited for studying tactic responses during the transition to multicellularity because they range in complexity from unicellular to multicellular genera. Phototactic responses are essential for these flagellates because they need to orientate themselves to receive sufficient light for photosynthesis, but how does a multicellular organism accomplish phototaxis without any known direct communication among cells? Several aspects of the photoresponse have previously been analyzed in volvocine algae, particularly in the unicellular alga Chlamydomonas. Results In this study, the phototactic behavior in the spheroidal, multicellular volvocine green alga Volvox rousseletii (Volvocales, Chlorophyta) was analyzed. In response to light stimuli, not only did the flagella waveform and beat frequency change, but the effective stroke was reversed. Moreover, there was a photoresponse gradient from the anterior to the posterior pole of the spheroid, and only cells of the anterior hemisphere showed an effective response. The latter caused a reverse of the fluid flow that was confined to the anterior hemisphere. The responsiveness to light is consistent with an anterior-to-posterior size gradient of eyespots. At the posterior pole, the eyespots are tiny or absent, making the corresponding cells appear to be blind. Pulsed light stimulation of an immobilized spheroid was used to simulate the light fluctuation experienced by a rotating spheroid during phototaxis. The results demonstrated that in free-swimming spheroids, only those cells of the anterior hemisphere that face toward the light source reverse the beating direction in the presence of illumination; this behavior results in phototactic turning. Moreover, positive phototaxis is facilitated by gravitational forces. Under

  17. A novel trypanoplasm-like flagellate Jarrellia atramenti n. g., n. sp. (Kinetoplastida: Bodonidae) and ciliates from the blowhole of a stranded pygmy sperm whale Kogia breviceps (Physeteridae): morphology, life cycle and potential pathogenicity.

    PubMed

    Poynton, S L; Whitaker, B R; Heinrich, A B

    2001-04-10

    The successful 6 mo rehabilitation of a stranded juvenile pygmy sperm whale Kogia breviceps afforded the opportunity to study the poorly known protozoan fauna of the upper respiratory tract of cetaceans. Mucus samples were collected by holding either a petri dish or glass slides over the blowhole for 3 to 5 exhalations; preparations were examined as wet mounts, and then stained with Wrights-Giemsa or Gram stain. Blood smears were stained with Wrights-Giemsa. Unidentified spindle-shaped and unidentified broad ciliates, reported from the blowhole of the pygmy sperm whale for the first time, were seen only initially, while yeast-like organisms and bacteria were seen intermittently. Epithelial cells and white blood cells were often present in the blowhole mucus, but red blood cells were never seen. A novel trypanoplasm-like bodonid kinetoplastid biflagellate (Order Kinetoplastida) was commonly encountered in the blowhole mucus, but never in the blood. Both mature flagellates and those undergoing longitudinal binary fission were present. The elongate flagellate had a long whiplash anterior flagellum; the recurrent flagellum was attached along at least two-thirds of the body length, forming a prominent undulating membrane, and the trailing portion was short. The kinetoplast was irregularly fragmented. The flagellates were either free-swimming, or attached to host material via the free portion of the posterior flagellum. The prominent undulating membrane was characteristic of Trypanoplasma, while the fragmented kinetoplast was characteristic of some species of Cryptobia. For the novel bodonid kinetoplastid, with its unique combination of morphological features (prominent undulating membrane and fragmented kinetoplast), we propose the creation of a new genus Jarrellia. We believe this to be the first published description of a flagellate from a marine mammal, and among the first reports of a trypanoplasm-like flagellate from a warm-blooded host. We expect that a diversity

  18. Algae-based oral recombinant vaccines.

    PubMed

    Specht, Elizabeth A; Mayfield, Stephen P

    2014-01-01

    Recombinant subunit vaccines are some of the safest and most effective vaccines available, but their high cost and the requirement of advanced medical infrastructure for administration make them impractical for many developing world diseases. Plant-based vaccines have shifted that paradigm by paving the way for recombinant vaccine production at agricultural scale using an edible host. However, enthusiasm for "molecular pharming" in food crops has waned in the last decade due to difficulty in developing transgenic crop plants and concerns of contaminating the food supply. Microalgae could be poised to become the next candidate in recombinant subunit vaccine production, as they present several advantages over terrestrial crop plant-based platforms including scalable and contained growth, rapid transformation, easily obtained stable cell lines, and consistent transgene expression levels. Algae have been shown to accumulate and properly fold several vaccine antigens, and efforts are underway to create recombinant algal fusion proteins that can enhance antigenicity for effective orally delivered vaccines. These approaches have the potential to revolutionize the way subunit vaccines are made and delivered - from costly parenteral administration of purified protein, to an inexpensive oral algae tablet with effective mucosal and systemic immune reactivity.

  19. Viruses and viruslike particles of eukaryotic algae.

    PubMed Central

    Van Etten, J L; Lane, L C; Meints, R H

    1991-01-01

    Until recently there was little interest or information on viruses and viruslike particles of eukaryotic algae. However, this situation is changing. In the past decade many large double-stranded DNA-containing viruses that infect two culturable, unicellular, eukaryotic green algae have been discovered. These viruses can be produced in large quantities, assayed by plaque formation, and analyzed by standard bacteriophage techniques. The viruses are structurally similar to animal iridoviruses, their genomes are similar to but larger (greater than 300 kbp) than that of poxviruses, and their infection process resembles that of bacteriophages. Some of the viruses have DNAs with low levels of methylated bases, whereas others have DNAs with high concentrations of 5-methylcytosine and N6-methyladenine. Virus-encoded DNA methyltransferases are associated with the methylation and are accompanied by virus-encoded DNA site-specific (restriction) endonucleases. Some of these enzymes have sequence specificities identical to those of known bacterial enzymes, and others have previously unrecognized specificities. A separate rod-shaped RNA-containing algal virus has structural and nucleotide sequence affinities to higher plant viruses. Quite recently, viruses have been associated with rapid changes in marine algal populations. In the next decade we envision the discovery of new algal viruses, clarification of their role in various ecosystems, discovery of commercially useful genes in these viruses, and exploitation of algal virus genetic elements in plant and algal biotechnology. Images PMID:1779928

  20. Effects of nitrogen dioxide on algae

    SciTech Connect

    Wodzinski, R.S.; Alexander, M.

    1980-01-01

    Photosynthetic activity of Anabaena flos-aquae in a soil suspension at an initial pH of 4.9 was almost totally eliminated after 3 days of exposure to 5.0 ppm (..mu..l/liter) NO/sub 2/, at which time the pH had fallen to 3.9. In contrast, A. flos-aquae in soil suspensions at an initial pH of 6.0 was not inhibited after 3 days by 5.0 ppm NO/sub 2/, but the activity was reduced by half in the presence of 15.0 ppm NO/sub 2/; the pH was 6.5 and 5.8, respectively, in the NO/sub 2/-treated samples on day 3. Photosynthesis by the green algae Chlamydomonas reinhardtii and Ankistrodesmus falcatus in soil suspensions at an initial pH of approx 4.2 was not appreciably affected by 15.0 ppm of NO/sub 2/ after 3 days, at which time the pH had fallen below 4.0. The high levels of NO/sub 2/ and low pH values required for toxicity suggest that blue-green and green algae probably will not be affected directly by NO/sub 2/ in polluted air.

  1. Effects of nitrogen dioxide on algae

    SciTech Connect

    Wodzinski, R.S.; Alexander, M.

    1980-01-01

    Photosynthetic activity of Anabaena flos-aquae in a soil suspension at an initial pH of 4.9 was almost totally eliminated after 3 days of exposure to 5.0 ppM (..mu..l/liter) NO/sub 2/, at which time the pH had fallen to 3.9. In contrast, A. flos-aquae in soil suspensions at an initial pH of 6.0 was not inhibited after 3 days by 5.0 ppM NO/sub 2/, but the activity was reduced by half in the presence of 15.0 ppM NO/sub 2/; the pH was 6.5 and 5.8, respectively, in the NO/sub 2/-treated samples on day 3. Photosynthesis by the green algae Chlamydomonas reinhardtii and Ankistrodesmus falcatus in soil suspensions at an initial pH of approx. 4.2 was not appreciably affected by 15.0 ppM of NO/sub 2/ after 3 days, at which time the pH had fallen below 4.0. The high levels of NO/sub 2/ and low pH values required for toxicity suggest that blue-green and green algae probably will not be affected directly by NO/sub 2/ in polluted air.

  2. Algae-based oral recombinant vaccines.

    PubMed

    Specht, Elizabeth A; Mayfield, Stephen P

    2014-01-01

    Recombinant subunit vaccines are some of the safest and most effective vaccines available, but their high cost and the requirement of advanced medical infrastructure for administration make them impractical for many developing world diseases. Plant-based vaccines have shifted that paradigm by paving the way for recombinant vaccine production at agricultural scale using an edible host. However, enthusiasm for "molecular pharming" in food crops has waned in the last decade due to difficulty in developing transgenic crop plants and concerns of contaminating the food supply. Microalgae could be poised to become the next candidate in recombinant subunit vaccine production, as they present several advantages over terrestrial crop plant-based platforms including scalable and contained growth, rapid transformation, easily obtained stable cell lines, and consistent transgene expression levels. Algae have been shown to accumulate and properly fold several vaccine antigens, and efforts are underway to create recombinant algal fusion proteins that can enhance antigenicity for effective orally delivered vaccines. These approaches have the potential to revolutionize the way subunit vaccines are made and delivered - from costly parenteral administration of purified protein, to an inexpensive oral algae tablet with effective mucosal and systemic immune reactivity. PMID:24596570

  3. Respiratory Chain of Colorless Algae II. Cyanophyta

    PubMed Central

    Webster, D. A.; Hackett, D. P.

    1966-01-01

    Whole cell difference spectra of the blue-green algae, Saprospira grandis, Leucothrix mucor, and Vitreoscilla sp. have one, or at the most 2, broad α-bands near 560 mμ. At −190° these bands split to give 4 peaks in the α-region for b and c-type cytochromes, but no α-band for a-type cytochromes is visible. The NADH oxidase activity of these organisms was shown to be associated with particulate fractions of cell homogenates. The response of this activity to inhibitors differed from the responses of the NADH oxidase activities of particulate preparations from the green algae and higher plants to the same inhibitors, but is more typical of certain bacteria. No cytochrome oxidase activity was present in these preparations. The respiration of Saprospira and Vitreoscilla can be light-reversibly inhibited by CO, and all 3 organisms have a CO-binding pigment whose CO complex absorbs near 570, 535, and 417 mμ. The action spectrum for the light reversal of CO-inhibited Vitreoscilla respiration shows maxima at 568, 534, and 416 mμ. The results suggest that the terminal oxidase in these blue-greens is an o-type cytochrome. Images PMID:5932404

  4. Algae Biofuels Co-Location Assessment Tool

    2013-09-18

    ABCLAT was built to help any model user with spatially explicit Nitrogen, Phosphorous, and Carbon Dioxide nutrient flux information, and solar resource information evaluate algal cultivation potential. Initial applications of this modeling framework include Algae Biofuels Co-Location Assessment Tool Canada and Australia. The Canadian application was copyrighted November 29th 2011 as the Algae Biofuels Co-Location Assessment Tool for Canada. This copyright assertion is for the general framework from which any country or region with themore » requisite data could create a regionally specific application. The ABCLAT model framework developed by SNL looks at the growth potential in a given region as a function of available nutrients from wastewater and other sources, carbon dioxide from power plants, available solar potential, and if available, land cover and use information. The model framework evaluates the biomass potential, fixed carbon dioxide, potential algal biocrude and required land area for nutrient sources. ABCLAT is built with an object-oriented software program that can provide an easy to use interface for exploring questions related to aigal biomass production.« less

  5. Algae Biofuels Co-Location Assessment Tool

    SciTech Connect

    2013-09-18

    ABCLAT was built to help any model user with spatially explicit Nitrogen, Phosphorous, and Carbon Dioxide nutrient flux information, and solar resource information evaluate algal cultivation potential. Initial applications of this modeling framework include Algae Biofuels Co-Location Assessment Tool Canada and Australia. The Canadian application was copyrighted November 29th 2011 as the Algae Biofuels Co-Location Assessment Tool for Canada. This copyright assertion is for the general framework from which any country or region with the requisite data could create a regionally specific application. The ABCLAT model framework developed by SNL looks at the growth potential in a given region as a function of available nutrients from wastewater and other sources, carbon dioxide from power plants, available solar potential, and if available, land cover and use information. The model framework evaluates the biomass potential, fixed carbon dioxide, potential algal biocrude and required land area for nutrient sources. ABCLAT is built with an object-oriented software program that can provide an easy to use interface for exploring questions related to aigal biomass production.

  6. Shewanella algae Peritonitis in Patients on Peritoneal Dialysis.

    PubMed

    Shanmuganathan, Malini; Goh, Bak Leong; Lim, Christopher; NorFadhlina, Zakaria; Fairol, Ibrahim

    Patients with peritonitis present with abdominal pain, diarrhea, fever, and turbid peritoneal dialysis (PD) fluid. Shewanella algae peritonitis has not yet been reported in PD patients in the literature. We present the first 2 cases of Shewanella algae peritonitis in PD patients. Mupirocin cream is applied on the exit site as prophylactic antibiotic therapy. PMID:27659933

  7. [Marine algae of Baja California Sur, Mexico: nutritional value].

    PubMed

    Carrillo Domínguez, Silvia; Casas Valdez, Margarita; Ramos Ramos, Felipe; Pérez-Gil, Fernando; Sánchez Rodríguez, Ignacio

    2002-12-01

    The Baja California Peninsula is one of the richest regions of seaweed resources in México. The objective of this study was to determine the chemical composition of some marine algae species of Baja California Sur, with an economical potential due to their abundance and distribution, and to promote their use as food for human consumption and animal feeding. The algae studied were Green (Ulva spp., Enteromorpha intestinalis, Caulerpa sertularoides, Bryopsis hypnoides), Red (Laurencia johnstonii, Spyridia filamentosa, Hypnea valentiae) and Brown (Sargassum herporizum, S. sinicola, Padina durvillaei, Hydroclathrus clathrathus, Colpomenia sinuosa). The algae were dried and ground before analysis. In general, the results showed that algae had a protein level less than 11%, except L. johnstonii with 18% and low energy content. The ether extract content was lower than 1%. However, the algae were a good source of carbohydrates and inorganic matter.

  8. Cryoalgotox: Use of cryopreserved alga in a semistatic microplate test

    SciTech Connect

    Benhra, A.; Radetski, C.M.; Ferard, J.F.

    1997-03-01

    Use of cryopreserved alga Selenastrum capricornutum has been evaluated as a simple and cost-efficient procedure in a new semistatic algal ecotoxicity test. Experiments have been conducted to compare performance criteria of this method, named Cryoalgotox, versus the classic microplate test using fresh algae. Cryoalgotox 72-h 50% effective concentrations (EC50s) determined with Cd{sup 2+}, Cu{sup 2+}, Cr{sup 6+}, and atrazine were more sensitive, repeatable (low coefficients of variation), and reproducible (low time effect) than the results obtained with the classical microplate tests. The effect of storage time at {minus}80 C on the sensitivity of the algae was assessed using cadmium as a toxic reference; it was shown that algae stored at {minus}80 C over a 3-month period gave comparable toxicity results to those found with fresh algae.

  9. Algae Farming in Low Earth Orbit: Past Present and Future

    NASA Astrophysics Data System (ADS)

    Morrison, N.

    Algal strains used as a production engine represent a novel example of living mechanical systems with tremendous potential for applications in space. Algae use photosynthesis to create lipids, glycerin, and biomass, with different strains of algae producing different oils. Algae can be grown to produce many types of oils, with low, medium or long hydrocarbon chain lengths. This article examines the history of algae research, as well as its value to astronauts as both a food supplement and as an oxygen production and carbon sequester engine. Consideration is given to ways algae is currently being used and tested in space, followed by a look forward envisioning dynamic living technological systems that can help to sustain our race as we travel the void between stars.

  10. Mitigating ammonia nitrogen deficiency in dairy wastewaters for algae cultivation.

    PubMed

    Lu, Qian; Zhou, Wenguang; Min, Min; Ma, Xiaochen; Ma, Yiwei; Chen, Paul; Zheng, Hongli; Doan, Yen T T; Liu, Hui; Chen, Chi; Urriola, Pedro E; Shurson, Gerald C; Ruan, Roger

    2016-02-01

    This study demonstrated that the limiting factor to algae growth on dairy wastewater was the ammonia nitrogen deficiency. Dairy wastewaters were mixed with a slaughterhouse wastewater that has much higher ammonia nitrogen content. The results showed the mixing wastewaters improved the nutrient profiles and biomass yield at low cost. Algae grown on mixed wastewaters contained high protein (55.98-66.91%) and oil content (19.10-20.81%) and can be exploited to produce animal feed and biofuel. Furthermore, algae grown on mixed wastewater significantly reduced nutrient contents remained in the wastewater after treatment. By mitigating limiting factor to algae growth on dairy wastewaters, the key issue of low biomass yield of algae grown on dairy wastewaters was resolved and the wastewater nutrient removal efficiency was significantly improved by this study.

  11. The reproductive toxicity on the rotifer Brachionus plicatilis induced by BDE-47 and studies on the effective mechanism based on antioxidant defense system changes.

    PubMed

    Wang, Hong; Tang, Xuexi; Sha, Jingjing; Chen, Hongmei; Sun, Tianli; Wang, You

    2015-09-01

    2,2',4,4'-Tetrabromodiphenyl ether (BDE-47), a low-brominated Tetra-BDE that is widely distributed in the marine ecosystem, was selected to investigate the reproductive toxicity on the rotifer, Brachionus plicatilis, and the possible mechanism based on antioxidant defense system changes were studied. The results showed the following: (1) A low concentration of BDE-47 had a slight effect on the egg production of individual females and the egg production rate (EPR) of the population. In fact, BDE-47 exerted reproductive inhibition effects in a time- and concentration-dependent manner. The obtained life tables indicated that BDE-47 at a high concentration prolonged the generation time, whereas low and moderate concentrations of BDE-47 had the opposite effects. BDE-47 at a medium concentration significantly decreased the life expectancy and net reproductive rate (P<0.05). Additionally, a high concentration of BDE-47 markedly decreased the net reproductive rate and intrinsic increase rate (P<0.05). The ultra-structure of the ovary showed that BDE-47 severely damaged the ovary. (2) BDE-47 stress elevated the ROS level in B. plicatilis. The GST activity was induced significantly by the low concentration of BDE-47 and inhibited by the highest concentration tested. The GPx activity and GSH content were significant decreased in all the tested groups, and GR activity was induced. GST and GSH appeared to be sensitive to oxidative stress, and all of the glutathione-related enzymes were found to play an important role in maintaining the antioxidant/pro-oxidant balance based on Pearson's correlation analysis. The results indicated that BDE-47 causes reproductive toxicity in B. plicatilis and that the ROS-mediated pathway is responsible for the observed toxicity.

  12. Morphological, morphometrical and molecular (CO1 and ITS) analysis of the rotifer Asplanchna brightwellii from selected freshwater bodies in Central Mexico.

    PubMed

    Jiménez-Contreras, Jorge; Sarma, S S S; Calderón-Torres, Marissa; Nandini, S

    2013-11-01

    We evaluated different strains of the rotifer Asplanchna brightwellii collected from central Mexico using morphology, morphometry and molecular tools (CO1 and ITS). Three distinct clonal populations from each of the 3 regions (Mexico City, State of Mexico and State of Guerrero) were established under laboratory conditions. For a given waterbody, morphometric comparisons within the populations of A. brightwellii showed almost stable measurements of trophi and with no statistically significant differences among them (p > 0.05). However, asplanchnid body length and width as well as the cyst diameter varied significantly depending on the waterbody from which A. brightwellii was collected. The smallest adults (about 700 microm) were from Valerio Trujano lake (Guerrero State) samples while the largest were from Xochimilco lake. Similar tendencies were reflected in the diameter of resting eggs. In addition, morphologically the cysts of A. brightwellii from the three waterbodies showed slightly different pattern. The number of globular structures on the surface of cysts was smaller for Valerio Trujano strain, while these were larger and less numerous for both Xochimilco and Zumpango strains. The ITS region tree displayed two groups Xochimilco and Valerio Trujano -Zumpango, this analysis did not reflect the morphological grouping; on the contrary the CO1 gene tree separated the populations according to morphological clusters and location (Xochimilco, Valerio Trujano and Zumpango lakes). When the tree was built using the combination of both ITS and CO1 sequences, the phylogenetic relationships observed on CO1 gene were consistent; but showed differences with the relationships observed on ITS region tree (only two groups).

  13. Auxin and cytoskeletal organization in algae.

    PubMed

    Jin, Qiaojun; Scherp, Peter; Heimann, Kirsten; Hasenstein, Karl H

    2008-05-01

    Hormones affect growth and alter the cytoskeleton suggesting that hormones and the cytoskeleton interact with each other. The cytoskeleton of ancestral algae such as Chara showed similar sensitivity to auxin as higher plants, even in generative structures but the sensitivity differed between IAA and alpha-NAA and presumably other auxins. The ability of cells to elongate depends on microtubule organization during the transition from disorganized to perpendicular to longitudinal organization of the cytoskeleton. Because of the many functions of the cytoskeleton it is possible that its composition is influenced by selective gene expression and adaptation to growth regulators. Co-localization of microtubules and F-actin change at a high temporal and spatial scale. High resolution measurements of mRNA expression indicate rapid turnover that may affect the composition of the cytoskeleton.

  14. High-fidelity phototaxis in biflagellate algae

    NASA Astrophysics Data System (ADS)

    Leptos, Kyriacos; Chioccioli, Maurizio; Furlan, Silvano; Pesci, Adriana; Goldstein, Raymond

    2015-11-01

    The single-cell alga Chlamydomonas reinhardtii is a motile biflagellate that can swim towards light for its photosynthetic requirements, a behavior referred to as phototaxis. The cell responds upon light stimulation through its rudimentary eye - the eyespot - by changing the beating amplitude of its two flagella accordingly - a process called the photoresponse. All this occurs in a coordinated fashion as Chlamydomonas spins about its body axis while swimming, thus experiencing oscillating intensities of light. We use high-speed video microscopy to measure the flagellar dynamics of the photoresponse on immobilized cells and interpret the results with a mathematical model of adaptation similar to that used previously for Volvox. These results are incorporated into a model of phototactic steering to yield trajectories that are compared to those obtained by three-dimensional tracking. Implications of these results for the evolution of multicellularity in the Volvocales are discussed.

  15. Autophagy in the model alga Chlamydomonas reinhardtii.

    PubMed

    Pérez-Pérez, María Esther; Crespo, José L

    2010-05-01

    Degradation and recycling of intracellular components via autophagy is conserved among eukaryotes. This catabolic process is mediated by autophagy-related (ATG) proteins, which have been identified in different systems including yeasts, mammals and plants. The genome of the model alga Chlamydomonas reinhardtii contains homologues to yeast and plant ATG genes although autophagy has not been previously described in this organism. In our study, we report the molecular characterization of autophagy in Chlamydomonas. Using the ATG8 protein from Chlamydomonas as a molecular autophagy marker, we demonstrate that this degradative process is induced in stationary cells or under different stresses such as nutrient limitation, oxidative stress or the accumulation of misfolded proteins in the endoplasmic reticulum. Our results also indicate that TOR, a major regulator of autophagy, inhibits this process in Chlamydomonas.

  16. Swimming like algae: biomimetic soft artificial cilia

    PubMed Central

    Sareh, Sina; Rossiter, Jonathan; Conn, Andrew; Drescher, Knut; Goldstein, Raymond E.

    2013-01-01

    Cilia are used effectively in a wide variety of biological systems from fluid transport to thrust generation. Here, we present the design and implementation of artificial cilia, based on a biomimetic planar actuator using soft-smart materials. This actuator is modelled on the cilia movement of the alga Volvox, and represents the cilium as a piecewise constant-curvature robotic actuator that enables the subsequent direct translation of natural articulation into a multi-segment ionic polymer metal composite actuator. It is demonstrated how the combination of optimal segmentation pattern and biologically derived per-segment driving signals reproduce natural ciliary motion. The amenability of the artificial cilia to scaling is also demonstrated through the comparison of the Reynolds number achieved with that of natural cilia. PMID:23097503

  17. Swimming like algae: biomimetic soft artificial cilia.

    PubMed

    Sareh, Sina; Rossiter, Jonathan; Conn, Andrew; Drescher, Knut; Goldstein, Raymond

    2013-01-01

    Cilia are used effectively in a wide variety of biological systems from fluid transport to thrust generation. Here, we present the design and implementation of artificial cilia, based on a biomimetic planar actuator using soft-smart materials. This actuator is modelled on the cilia movement of the alga Volvox, and represents the cilium as a piecewise constant-curvature robotic actuator that enables the subsequent direct translation of natural articulation into a multi-segment ionic polymer metal composite actuator. It is demonstrated how the combination of optimal segmentation pattern and biologically derived per-segment driving signals reproduce natural ciliary motion. The amenability of the artificial cilia to scaling is also demonstrated through the comparison of the Reynolds number achieved with that of natural cilia. PMID:23097503

  18. Random flow induced by swimming algae

    NASA Astrophysics Data System (ADS)

    Kantsler, Vasily; Rushkin, Ilia; Goldstein, Raymond

    2010-11-01

    In this work we studied the random flow induced in a fluid by the motion of a dilute suspension of the swimming algae Volvox carteri. The fluid velocity in the suspension is a superposition of the flow fields set up by the individual organisms, which in turn have multipole contributions that decay as inverse powers of distance from the organism. Here we show that the conditions under which the central limit theorem guarantees a Gaussian probability distribution function of velocity fluctuations are satisfied when the leading force singularity is a Stokeslet. Deviations from Gaussianity are shown to arise from near-field effects. Comparison is made with the statistical properties of abiotic sedimenting suspensions. The experimental results are supplemented by extensive numerical studies.

  19. Chloroplast Phylogenomic Inference of Green Algae Relationships

    PubMed Central

    Sun, Linhua; Fang, Ling; Zhang, Zhenhua; Chang, Xin; Penny, David; Zhong, Bojian

    2016-01-01

    The green algal phylum Chlorophyta has six diverse classes, but the phylogenetic relationship of the classes within Chlorophyta remains uncertain. In order to better understand the ancient Chlorophyta evolution, we have applied a site pattern sorting method to study compositional heterogeneity and the model fit in the green algal chloroplast genomic data. We show that the fastest-evolving sites are significantly correlated with among-site compositional heterogeneity, and these sites have a much poorer fit to the evolutionary model. Our phylogenomic analyses suggest that the class Chlorophyceae is a monophyletic group, and the classes Ulvophyceae, Trebouxiophyceae and Prasinophyceae are non-monophyletic groups. Our proposed phylogenetic tree of Chlorophyta will offer new insights to investigate ancient green algae evolution, and our analytical framework will provide a useful approach for evaluating and mitigating the potential errors of phylogenomic inferences. PMID:26846729

  20. An algae-covered alligator rests warily

    NASA Technical Reports Server (NTRS)

    2000-01-01

    An algae-covered alligator keeps a wary eye open as it rests in one of the ponds at Kennedy Space Center. American alligators feed and rest in the water, and lay their eggs in dens they dig into the banks. The young alligators spend their first several weeks in these dens. The Center shares a boundary with the Merritt Island National Wildlife Refuge, which encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  1. Granular activated algae for wastewater treatment.

    PubMed

    Tiron, O; Bumbac, C; Patroescu, I V; Badescu, V R; Postolache, C

    2015-01-01

    The study used activated algae granules for low-strength wastewater treatment in sequential batch mode. Each treatment cycle was conducted within 24 h in a bioreactor exposed to 235 μmol/m²/s light intensity. Wastewater treatment was performed mostly in aerobic conditions, oxygen being provided by microalgae. High removal efficiency of chemical oxygen demand (COD) was achieved (86-98%) in the first hours of the reaction phase, during which the indicator's removal rate was 17.4 ± 3.9 mg O₂/g h; NH(4)(+) was removed during organic matter degradation processes with a rate of 1.8 ± 0.6 mg/g h. After almost complete COD removal, the (O⁺) remaining in the liquor was removed through nitrification processes promoted by the increase of the liquor's oxygen saturation (O₂%), the transformation rate of NH4(+) into NO(3)(-) increasing from 0.14 ± 0.05 to 1.5 ± 0.4 mg NH4(+)/g h, along with an O₂% increase. A wide removal efficiency was achieved in the case of PO(4)(3)(-) (11-85%), with the indicator's removal rate being 1.3 ± 0.7 mg/g h. In the provided optimum conditions, the occurrence of the denitrifying activity was also noticed. A large pH variation was registered (5-8.5) during treatment cycles. The granular activated algae system proved to be a promising alternative for wastewater treatment as it also sustains cost-efficient microalgae harvesting, with microalgae recovery efficiency ranging between 99.85 and 99.99% after granules settling with a velocity of 19 ± 3.6 m/h.

  2. Coprophilic amoebae and flagellates, including Guttulinopsis, Rosculus and Helkesimastix, characterise a divergent and diverse rhizarian radiation and contribute to a large diversity of faecal-associated protists.

    PubMed

    Bass, David; Silberman, Jeffrey D; Brown, Matthew W; Pearce, Rebecca A; Tice, Alexander K; Jousset, Alexandre; Geisen, Stefan; Hartikainen, Hanna

    2016-05-01

    A wide diversity of organisms utilize faecal habitats as a rich nutrient source or a mechanism to traverse through animal hosts. We sequenced the 18S rRNA genes of the coprophilic, fruiting body-forming amoeba Guttulinopsis vulgaris and its non-fruiting relatives Rosculus 'ithacus' CCAP 1571/3, R. terrestris n. sp. and R. elongata n. sp. and demonstrate that they are related to the coprophilic flagellate Helkesimastix in a strongly supported, but highly divergent 18S sister clade. PCR primers specific to both clades were used to generate 18S amplicons from a range of environmental and faecal DNA samples. Phylogenetic analysis of the cloned sequences demonstrated a high diversity of uncharacterised sequence types within this clade, likely representing previously described members of the genera Guttulinopsis, Rosculus and Helkesimastix, as well as so-far unobserved organisms. Further, an Illumina MiSeq sequenced set of 18S V4-region amplicons generated from faecal DNAs using universal eukaryote primers showed that core-cercozoan assemblages in faecal samples are as diverse as those found in more conventionally examined habitats. These results reveal many novel lineages, some of which appear to occur preferentially in faecal material, in particular cercomonads and glissomonads. More broadly, we show that faecal habitats are likely untapped reservoirs of microbial eukaryotic diversity. PMID:26914587

  3. Ultrastructure and 18S rDNA sequence analysis of Wobblia lunata gen. et sp. nov., a new heterotrophic flagellate (Stramenopiles, Incertae sedis).

    PubMed

    Moriya, M; Nakayama, T; Inouye, I

    2000-05-01

    A new heterotrophic flagellate Wobblia lunata gen. et sp. nov. is described. This organism usually attaches to the substratum showing a wobbling motion, and sometimes glides on the substratum or swims freely in the medium. W. lunata has various features characteristic of the stramenopiles. These include a hairy flagellum with tripartite tubular hairs, a mitochondrion with tubular cristae, arrangement of flagellar apparatus components and a double helix in the flagellar transition zone. W. lunata shares a double helix with heterotrophic stramenopiles, including Developayella elegans, oomycetes, hyphochytrids, opalinids and proteromonads, and could be placed in the phylum Bigyra Cavalier-Smith. However, from 18S rDNA tree analysis, these organisms form two distantly-related clades in the stramenopiles, and Wobblia appears at the base of the stramenopiles. Evaluation of morphological features and comparison of 18S rDNA sequences indicate that W. lunata is a member of the stramenopiles, but it is distinct from any other stramenopiles so far described. Its phylogenetic position within the stramenopiles is uncertain and therefore W. lunata is described as a stramenopile incertae sedis. PMID:10896132

  4. 'Candidatus Adiutrix intracellularis', an endosymbiont of termite gut flagellates, is the first representative of a deep-branching clade of Deltaproteobacteria and a putative homoacetogen.

    PubMed

    Ikeda-Ohtsubo, Wakako; Strassert, Jürgen F H; Köhler, Tim; Mikaelyan, Aram; Gregor, Ivan; McHardy, Alice C; Tringe, Susannah Green; Hugenholtz, Phil; Radek, Renate; Brune, Andreas

    2016-09-01

    Termite gut flagellates are typically colonized by specific bacterial symbionts. Here we describe the phylogeny, ultrastructure and subcellular location of 'Candidatus Adiutrix intracellularis', an intracellular symbiont of Trichonympha collaris in the termite Zootermopsis nevadensis. It represents a novel, deep-branching clade of uncultured Deltaproteobacteria widely distributed in intestinal tracts of termites and cockroaches. Fluorescence in situ hybridization and transmission electron microscopy localized the endosymbiont near hydrogenosomes in the posterior part and near the ectosymbiont 'Candidatus Desulfovibrio trichonymphae' in the anterior part of the host cell. The draft genome of 'Ca. Adiutrix intracellularis' obtained from a metagenomic library revealed the presence of a complete gene set encoding the Wood-Ljungdahl pathway, including two homologs of fdhF encoding hydrogenase-linked formate dehydrogenases (FDHH ) and all other components of the recently described hydrogen-dependent carbon dioxide reductase (HDCR) complex, which substantiates previous claims that the symbiont is capable of reductive acetogenesis from CO2 and H2 . The close phylogenetic relationship between the HDCR components and their homologs in homoacetogenic Firmicutes and Spirochaetes suggests that the deltaproteobacterium acquired the capacity for homoacetogenesis via lateral gene transfer. The presence of genes for nitrogen fixation and the biosynthesis of amino acids and cofactors indicate the nutritional nature of the symbiosis.

  5. 'Candidatus Adiutrix intracellularis', an endosymbiont of termite gut flagellates, is the first representative of a deep-branching clade of Deltaproteobacteria and a putative homoacetogen.

    PubMed

    Ikeda-Ohtsubo, Wakako; Strassert, Jürgen F H; Köhler, Tim; Mikaelyan, Aram; Gregor, Ivan; McHardy, Alice C; Tringe, Susannah Green; Hugenholtz, Phil; Radek, Renate; Brune, Andreas

    2016-09-01

    Termite gut flagellates are typically colonized by specific bacterial symbionts. Here we describe the phylogeny, ultrastructure and subcellular location of 'Candidatus Adiutrix intracellularis', an intracellular symbiont of Trichonympha collaris in the termite Zootermopsis nevadensis. It represents a novel, deep-branching clade of uncultured Deltaproteobacteria widely distributed in intestinal tracts of termites and cockroaches. Fluorescence in situ hybridization and transmission electron microscopy localized the endosymbiont near hydrogenosomes in the posterior part and near the ectosymbiont 'Candidatus Desulfovibrio trichonymphae' in the anterior part of the host cell. The draft genome of 'Ca. Adiutrix intracellularis' obtained from a metagenomic library revealed the presence of a complete gene set encoding the Wood-Ljungdahl pathway, including two homologs of fdhF encoding hydrogenase-linked formate dehydrogenases (FDHH ) and all other components of the recently described hydrogen-dependent carbon dioxide reductase (HDCR) complex, which substantiates previous claims that the symbiont is capable of reductive acetogenesis from CO2 and H2 . The close phylogenetic relationship between the HDCR components and their homologs in homoacetogenic Firmicutes and Spirochaetes suggests that the deltaproteobacterium acquired the capacity for homoacetogenesis via lateral gene transfer. The presence of genes for nitrogen fixation and the biosynthesis of amino acids and cofactors indicate the nutritional nature of the symbiosis. PMID:26914459

  6. [Mutants of bacterium Azospirillum brasilense Sp245 with Omegon insertion in mmsB or fabG genes of lipid metabolism are defective in motility and flagellation].

    PubMed

    Kovtunov, E A; Shelud'ko, A V; Chernyshova, M P; Petrova, L P; Katsy, E I

    2013-11-01

    Bacteria Azospirillum brasilense have mixed flagellation: in addition to the polar flagellum, numerous lateral flagella are formed in their cells on medium with increased density. Flagella determine the active swimming and swarming capacities of azospirilla. Using A. brasilense Sp245 as an example, we showed that the Omegon-Km artificial transposon insertion into the chromosomal gene for 3-hydroxyisobutyrate dehydrogenase (mmsB) was concurrent with the appearance of significant defects in the formation of polar flagella and with the paralysis of lateral flagella. The Sp245 mutant with the Omegon insertion into the plasmid AZOBR_p1-borne gene for 3-oxoacyl-[acyl-carrier protein]-reductase (fabG) showed the complete loss of flagella and the swarming capacity, as well as significant defects in polar flagellar assembly (though some cells are still motile in liquid medium). The viability of the A. brasilense Sp245 mutants with the Omegon insertion into the mmsB or fabG gene was not reduced. No considerable differences in the fatty acid composition of whole cell lipid extracts were found for the A. brasilense Sp245 strain and its mmsB and fabG mutants.

  7. Mitochondrial and nuclear localization of topoisomerase II in the flagellate Bodo saltans (Kinetoplastida), a species with non-catenated kinetoplast DNA.

    PubMed

    Gaziová, Ivana; Lukes, Julius

    2003-03-28

    We have studied topoisomerase II (topo II) in the cells of Bodo saltans, a free-living bodonid (Kinetoplastida). Phylogenetic analysis based on the sequence of the entire topo II gene, which is a single-copy gene, confirmed that B. saltans is a predecessor of parasitic trypanosomatids. Antibodies generated against either an overexpressed unique C-terminal region of topo II or a synthetic oligopeptide derived from the same region did not cross-react with cell lysates of related trypanosomatids, while they recognized a single specific band in the B. saltans lysate. Immunolocalization experiments using both antibodies showed that topo II is evenly dispersed throughout the kinetoplast. This is in striking difference from the localization of topo II in other flagellates, where it occurs in two antipodal centers flanking the kinetoplast disk. Moreover, the same topo II has a distinct localization in multiple loci at the periphery of the nucleus of B. saltans. With a minicircle probe derived from the conserved region we have shown that all relaxed non-catenated minicircles are confined to the globular kinetoplast DNA bundle. Therefore, in the mitochondrion of this primitive eukaryote topo II does not catenate relaxed DNA circles into a network in vivo, while a decatenating activity is present in partially purified cell lysates.

  8. Phylogenetic diversity and whole-cell hybridization of oxymonad flagellates from the hindgut of the wood-feeding lower termite Reticulitermes flavipes.

    PubMed

    Stingl, Ulrich; Brune, Andreas

    2003-04-01

    SSU rRNA genes of oxymonad protists from the hindgut of the wood-feeding termite Reticulitermes flavipes were PCR-amplified using a newly designed oxymonad-specific forward primer and a newly designed reverse primer specific for termite gut flagellates. After cloning, the clone library was sorted into four groups by RFLP analysis and nearly full-length SSU rRNA gene sequences were obtained for representative clones from each group. Phylogenetic analysis revealed that sequences of all four groups formed a monophyletic cluster with the only other existing SSU rRNA gene sequence of oxymonads. Using whole-cell hybridization with clone-specific fluorescently labeled probes, each of the four clone groups could be assigned to a specific morphotype, which were identified as Dinenympha gracilis, Dinenympha fimbriata, and so-far undescribed species of Pyrsonympha and Dinenympha. Our results demonstrate that the morphological variety of oxymonads is not caused by the presence of different developmental stages of the same organism, but that the various morphotypes represent different species.

  9. Identification and characterization of ectosymbionts of distinct lineages in Bacteroidales attached to flagellated protists in the gut of termites and a wood-feeding cockroach.

    PubMed

    Noda, Satoko; Inoue, Tetsushi; Hongoh, Yuichi; Kawai, Miho; Nalepa, Christine A; Vongkaluang, Charunee; Kudo, Toshiaki; Ohkuma, Moriya

    2006-01-01

    Bacterial attachments to nearly the entire surface of flagellated protists in the guts of termites and the wood-feeding cockroach Cryptocercus are often observed. Based on the polymerase chain reaction-amplified 16S rRNA gene sequences, we investigated the phylogenetic relationships of the rod-shaped, attached bacteria (ectosymbionts) of several protist species from five host taxa and confirmed their identity by fluorescence in situ hybridizations. These ectosymbionts are affiliated with the order Bacteroidales but formed three distinct lineages, each of which may represent novel bacterial genera. One lineage consisted of the closely related ectosymbionts of two species of the protist genus Devescovina (Cristamonadida). The second lineage comprised three phylotypes identified from the protist Streblomastix sp. (Oxymonadida). The third lineage included ectosymbionts of the three protist genera Hoplonympha, Barbulanympha and Urinympha in the family Hoplonymphidae (Trichonymphida). The ultrastructural observations indicated that these rod-shaped ectosymbionts share morphological similarities of their cell walls and their point of attachment with the protist but differ in shape. Elongated forms of the ectosymbionts appeared in all the three lineages. The protist cells Streblomastix sp. and Hoplonympha sp. display deep furrows and vane-like structures, but these impressive structures are probably evolutionarily convergent because both the host protists and their ectosymbionts are distantly related.

  10. Coprophilic amoebae and flagellates, including Guttulinopsis, Rosculus and Helkesimastix, characterise a divergent and diverse rhizarian radiation and contribute to a large diversity of faecal-associated protists.

    PubMed

    Bass, David; Silberman, Jeffrey D; Brown, Matthew W; Pearce, Rebecca A; Tice, Alexander K; Jousset, Alexandre; Geisen, Stefan; Hartikainen, Hanna

    2016-05-01

    A wide diversity of organisms utilize faecal habitats as a rich nutrient source or a mechanism to traverse through animal hosts. We sequenced the 18S rRNA genes of the coprophilic, fruiting body-forming amoeba Guttulinopsis vulgaris and its non-fruiting relatives Rosculus 'ithacus' CCAP 1571/3, R. terrestris n. sp. and R. elongata n. sp. and demonstrate that they are related to the coprophilic flagellate Helkesimastix in a strongly supported, but highly divergent 18S sister clade. PCR primers specific to both clades were used to generate 18S amplicons from a range of environmental and faecal DNA samples. Phylogenetic analysis of the cloned sequences demonstrated a high diversity of uncharacterised sequence types within this clade, likely representing previously described members of the genera Guttulinopsis, Rosculus and Helkesimastix, as well as so-far unobserved organisms. Further, an Illumina MiSeq sequenced set of 18S V4-region amplicons generated from faecal DNAs using universal eukaryote primers showed that core-cercozoan assemblages in faecal samples are as diverse as those found in more conventionally examined habitats. These results reveal many novel lineages, some of which appear to occur preferentially in faecal material, in particular cercomonads and glissomonads. More broadly, we show that faecal habitats are likely untapped reservoirs of microbial eukaryotic diversity.

  11. The origin of red algae and the evolution of chloroplasts.

    PubMed

    Moreira, D; Le Guyader, H; Philippe, H

    2000-05-01

    Chloroplast structure and genome analyses support the hypothesis that three groups of organisms originated from the primary photosynthetic endosymbiosis between a cyanobacterium and a eukaryotic host: green plants (green algae + land plants), red algae and glaucophytes (for example, Cyanophora). Although phylogenies based on several mitochondrial genes support a specific green plants/red algae relationship, the phylogenetic analysis of nucleus-encoded genes yields inconclusive, sometimes contradictory results. To address this problem, we have analysed an alternative nuclear marker, elongation factor 2, and included new red algae and protist sequences. Here we provide significant support for a sisterhood of green plants and red algae. This sisterhood is also significantly supported by a multi-gene analysis of a fusion of 13 nuclear markers (5,171 amino acids). In addition, the analysis of an alternative fusion of 6 nuclear markers (1,938 amino acids) indicates that glaucophytes may be the closest relatives to the green plants/red algae group. Thus, our study provides evidence from nuclear markers for a single primary endosymbiosis at the origin of these groups, and supports a kingdom Plantae comprising green plants, red algae and glaucophytes.

  12. Isoprenoid biosynthesis in eukaryotic phototrophs: A spotlight on algae

    SciTech Connect

    Lohr M.; Schwender J.; Polle, J. E. W.

    2012-04-01

    Isoprenoids are one of the largest groups of natural compounds and have a variety of important functions in the primary metabolism of land plants and algae. In recent years, our understanding of the numerous facets of isoprenoid metabolism in land plants has been rapidly increasing, while knowledge on the metabolic network of isoprenoids in algae still lags behind. Here, current views on the biochemistry and genetics of the core isoprenoid metabolism in land plants and in the major algal phyla are compared and some of the most pressing open questions are highlighted. Based on the different evolutionary histories of the various groups of eukaryotic phototrophs, we discuss the distribution and regulation of the mevalonate (MVA) and the methylerythritol phosphate (MEP) pathways in land plants and algae and the potential consequences of the loss of the MVA pathway in groups such as the green algae. For the prenyltransferases, serving as gatekeepers to the various branches of terpenoid biosynthesis in land plants and algae, we explore the minimal inventory necessary for the formation of primary isoprenoids and present a preliminary analysis of their occurrence and phylogeny in algae with primary and secondary plastids. The review concludes with some perspectives on genetic engineering of the isoprenoid metabolism in algae.

  13. Algae biomass cultivation in nitrogen rich biogas digestate.

    PubMed

    Krustok, I; Diaz, J G; Odlare, M; Nehrenheim, E

    2015-01-01

    Because microalgae are known for quick biomass growth and nutrient uptake, there has been much interest in their use in research on wastewater treatment methods. While many studies have concentrated on the algal treatment of wastewaters with low to medium ammonium concentrations, there are several liquid waste streams with high ammonium concentrations that microalgae could potentially treat. The aim of this paper was to test ammonium tolerance of the indigenous algae community of Lake Mälaren and to use this mixed consortia of algae to remove nutrients from biogas digestate. Algae from Lake Mälaren were cultivated in Jaworski's Medium containing a range of ammonium concentrations and the resulting algal growth was determined. The algae were able to grow at NH4-N concentrations of up to 200 mg L(-1) after which there was significant inhibition. To test the effectiveness of the lake water algae on the treatment of biogas digestate, different pre-cultivation set-ups and biogas digestate concentrations were tested. It was determined that mixing pre-cultivated suspension algae with 25% of biogas digestate by volume, resulting in an ammonium concentration of around 300 mg L(-1), produced the highest algal growth. The algae were effective in removing 72.8±2.2% of NH4-N and 41.4±41.4% of PO4-P. PMID:26540532

  14. Biomass of algae growth on natural water medium.

    PubMed

    Ramaraj, Rameshprabu; Tsai, David Dah-Wei; Chen, Paris Honglay

    2015-01-01

    Algae are the dominant primary producers in aquatic ecosystems. Since algae are highly varied group organisms, which have important functions in ecosystem, and their biomass is an essential biological resource. Currently, algae have been applied increasingly to diverse range of biomass applications. Therefore, this study was aimed to investigate the ecological algae features of microalgal production by natural medium, ecological function by lab scale of the symbiotic reactor which is imitated nature ecosystem, and atmospheric CO2 absorption that was related the algal growth of biomass to understand algae in natural water body better. Consequently, this study took advantages of using the unsupplemented freshwater natural medium to produce microalgae. Algal biomass by direct measurement of total suspended solids (TSS) and volatile suspended solids (VSS) resulted as 0.14g/L and 0.08g/L respectively. The biomass measurements of TSS and VSS are the sensible biomass index for algae production. The laboratory results obtained in the present study proved the production of algae by the natural water medium is potentially feasible.

  15. Algae biomass cultivation in nitrogen rich biogas digestate.

    PubMed

    Krustok, I; Diaz, J G; Odlare, M; Nehrenheim, E

    2015-01-01

    Because microalgae are known for quick biomass growth and nutrient uptake, there has been much interest in their use in research on wastewater treatment methods. While many studies have concentrated on the algal treatment of wastewaters with low to medium ammonium concentrations, there are several liquid waste streams with high ammonium concentrations that microalgae could potentially treat. The aim of this paper was to test ammonium tolerance of the indigenous algae community of Lake Mälaren and to use this mixed consortia of algae to remove nutrients from biogas digestate. Algae from Lake Mälaren were cultivated in Jaworski's Medium containing a range of ammonium concentrations and the resulting algal growth was determined. The algae were able to grow at NH4-N concentrations of up to 200 mg L(-1) after which there was significant inhibition. To test the effectiveness of the lake water algae on the treatment of biogas digestate, different pre-cultivation set-ups and biogas digestate concentrations were tested. It was determined that mixing pre-cultivated suspension algae with 25% of biogas digestate by volume, resulting in an ammonium concentration of around 300 mg L(-1), produced the highest algal growth. The algae were effective in removing 72.8±2.2% of NH4-N and 41.4±41.4% of PO4-P.

  16. [Seasonal variation characteristics of algae biomass in Chaohu Lake].

    PubMed

    Jiang, Xia; Wang, Shu-Hang; Zhong, Li-Xiang; Jin, Xiang-Can; Sun, Shi-Qun

    2010-09-01

    The biomass and distribution of algae community in Chaohu Lake were investigated in 2008. At the same time, the seasonal variations of algae translocation between the sediment and overlying water were also quantitative studied by self-made "algae up/down trap". Chaohu Lake was dominated by Cyanobacteria all the year, and dominant Cyanobacteria species changed in different seasons. In spring, Anabaena was the dominant species, and Microcystis was the subdominant species; In the whole summer and autumn, the dominant species is Microcystis. Algae biomass increased significantly from May and the maximum appeared in August, was 146.37 mg x m(-3) with Chl-a. The value of algae biomass were 9.75-16.24 mg x kg(-1) in the surface sediments, and the minimum appeared in Summer, then the algae biomass increased gradually with the maximum value in winter. Translocation process between the sediment and the overlying water occurred throughout the study period. The recruitment rates increased at first with the maximum rates in early August, was 0.036 8 mg x (m2 x d) (-1), and then had a downward tendency. However the sedimentation rates increased slowly firstly with the maximum rate in early September, then it decreased sharply, was 0.032 1 mg x (m2 x d)(-1). Multiple stepwise regression showed that temperature was the most significant factor for the algae biomass in Chaohu Lake, Total nitrogen (TN) and Total phosphorus(TP) are sub-important factors.

  17. Photophysiology and cellular composition of sea ice algae

    SciTech Connect

    Lizotte, M.P.

    1989-01-01

    The productivity of sea ice algae depends on their physiological capabilities and the environmental conditions within various microhabitats. Pack ice is the dominant form of sea ice, but the photosynthetic activity of associated algae has rarely been studied. Biomass and photosynthetic rates of ice algae of the Weddell-Scotia Sea were investigated during autumn and winter, the period when ice cover grows from its minimum to maximum. Biomass-specific photosynthetic rates typically ranged from 0.3 to 3.0 {mu}g C {center dot} {mu}g chl{sup {minus}1} {center dot} h{sup {minus}1} higher than land-fast ice algae but similar to Antarctic phytoplankton. Primary production in the pack ice during winter may be minor compared to annual phytoplankton production, but could represent a vital seasonal contribution to the Antarctic ecosystem. Nutrient supply may limit the productivity of ice algae. In McMurdo Sound, congelation ice algae appeared to be more nutrient deficient than underlying platelet ice algae based on: lower nitrogen:carbon, chlorophyll:carbon, and protein:carbohydrate; and {sup 14}C-photosynthate distribution to proteins and phospholipids was lower, while distribution to polysaccharides and neutral lipids was higher. Depletion of nitrate led to decreased nitrogen:carbon, chlorophyll:carbon, protein:carbohydrate, and {sup 14}C-photosynthate to proteins. Studied were conducted during the spring bloom; therefore, nutrient limitation may only apply to dense ice algal communities. Growth limiting conditions may be alleviated when algae are released into seawater during the seasonal recession of the ice cover. To continue growth, algae must adapt to the variable light field encountered in a mixed water column. Photoadaptation was studied in surface ice communities and in bottom ice communities.

  18. Activated chemical defenses suppress herbivory on freshwater red algae.

    PubMed

    Goodman, Keri M; Hay, Mark E

    2013-04-01

    The rapid life cycles of freshwater algae are hypothesized to suppress selection for chemical defenses against herbivores, but this notion remains untested. Investigations of chemical defenses are rare for freshwater macrophytes and absent for freshwater red algae. We used crayfish to assess the palatability of five freshwater red algae relative to a palatable green alga and a chemically defended aquatic moss. We then assessed the roles of structural, nutritional, and chemical traits in reducing palatability. Both native and non-native crayfish preferred the green alga Cladophora glomerata to four of the five red algae. Batrachospermum helminthosum, Kumanoa holtonii, and Tuomeya americana employed activated chemical defenses that suppressed feeding by 30-60 % following damage to algal tissues. Paralemanea annulata was defended by its cartilaginous structure, while Boldia erythrosiphon was palatable. Activated defenses are thought to reduce ecological costs by expressing potent defenses only when actually needed; thus, activation might be favored in freshwater red algae whose short-lived gametophytes must grow and reproduce rapidly over a brief growing season. The frequency of activated chemical defenses found here (three of five species) is 3-20× higher than for surveys of marine algae or aquatic vascular plants. If typical for freshwater red algae, this suggests that (1) their chemical defenses may go undetected if chemical activation is not considered and (2) herbivory has been an important selective force in the evolution of freshwater Rhodophyta. Investigations of defenses in freshwater rhodophytes contribute to among-system comparisons and provide insights into the generality of plant-herbivore interactions and their evolution.

  19. Photobiological hydrogen production with switchable photosystem-II designer algae

    DOEpatents

    Lee, James Weifu

    2014-02-18

    A process for enhanced photobiological H.sub.2 production using transgenic alga. The process includes inducing exogenous genes in a transgenic alga by manipulating selected environmental factors. In one embodiment inducing production of an exogenous gene uncouples H.sub.2 production from existing mechanisms that would downregulate H.sub.2 production in the absence of the exogenous gene. In other embodiments inducing an exogenous gene triggers a cascade of metabolic changes that increase H.sub.2 production. In some embodiments the transgenic alga are rendered non-regenerative by inducing exogenous transgenes for proton channel polypeptides that are targeted to specific algal membranes.

  20. Application of synthetic biology in cyanobacteria and algae

    PubMed Central

    Wang, Bo; Wang, Jiangxin; Zhang, Weiwen; Meldrum, Deirdre R.

    2012-01-01

    Cyanobacteria and algae are becoming increasingly attractive cell factories for producing renewable biofuels and chemicals due to their ability to capture solar energy and CO2 and their relatively simple genetic background for genetic manipulation. Increasing research efforts from the synthetic biology approach have been made in recent years to modify cyanobacteria and algae for various biotechnological applications. In this article, we critically review recent progresses in developing genetic tools for characterizing or manipulating cyanobacteria and algae, the applications of genetically modified strains for synthesizing renewable products such as biofuels and chemicals. In addition, the emergent challenges in the development and application of synthetic biology for cyanobacteria and algae are also discussed. PMID:23049529

  1. Evaluation of filamentous green algae as feedstocks for biofuel production.

    PubMed

    Zhang, Wei; Zhao, Yonggang; Cui, Binjie; Wang, Hui; Liu, Tianzhong

    2016-11-01

    Compared with unicellular microalgae, filamentous algae have high resistance to grazer-predation and low-cost recovery in large-scale production. Green algae, as the most diverse group of algae, included numerous filamentous genera and species. In this study, records of filamentous genera and species in green algae were firstly censused and classified. Then, seven filamentous strains subordinated in different genera were cultivated in bubbled-column to investigate their growth rate and energy molecular (lipid and starch) capacity. Four strains including Stigeoclonium sp., Oedogonium nodulosum, Hormidium sp. and Zygnema extenue were screened out due to their robust growth. And they all could accumulate triacylglycerols and starch in their biomass, but with different capacity. After nitrogen starvation, Hormidium sp. and Oedogonium nodulosum respectively exhibited high capacity of lipid (45.38% in dry weight) and starch (46.19% in dry weight) accumulation, which could be of high potential as feedstocks for biodiesel and bioethanol production. PMID:27598569

  2. Colourful Cultures: Classroom Experiments with the Unicellular Alga Haematococcus pluvialis.

    ERIC Educational Resources Information Center

    Delpech, Roger

    2001-01-01

    Describes an investigation into the photosynthetic potential of the different developmental stages of the green unicellular alga Haematococcus pluvialis. Reviews the biotechnological applications of astaxanthin, the red pigment which can be extracted from Haematococcus pluvialis. (Author/MM)

  3. Bicarbonate produced from carbon capture for algae culture.

    PubMed

    Chi, Zhanyou; O'Fallon, James V; Chen, Shulin

    2011-11-01

    Using captured CO(2) to grow microalgae is limited by the high cost of CO(2) capture and transportation, as well as significant CO(2) loss during algae culture. Moreover, algae grow poorly at night, but CO(2) cannot be temporarily stored until sunrise. To address these challenges, we discuss a process where CO(2) is captured as bicarbonate and used as feedstock for algae culture, and the carbonate regenerated by the culture process is used as an absorbent to capture more CO(2). This process would significantly reduce carbon capture costs because it does not require additional energy for carbonate regeneration. Furthermore, not only would transport of the aqueous bicarbonate solution cost less than for that of compressed CO(2), but using bicarbonate would also provide a superior alternative for CO(2) delivery to an algae culture system.

  4. CONTROL TECHNOLOGY EXTRACTION OF MERCURY FROM GROUNDWATER IMMOBILIZED ALGAE

    EPA Science Inventory

    Bio-Recovery Systems, Inc. conducted a project under the Emerging Technology portion of the United States Environmental Protection Agency (EPAs) Superfund Innovative Technology Evaluation (SITE) Program to evaluate the ability of immobilized algae to adsorb mercury from contamina...

  5. Harmful algae blooms removal from fresh water with modified vermiculite.

    PubMed

    Miao, Chunguang; Tang, Yi; Zhang, Hong; Wu, Zhengyan; Wang, Xiangqin

    2014-01-01

    Vermiculite and vermiculite modified with hydrochloric acid were investigated to evaluate their flocculation efficiencies in freshwater containing harmful algae blooms (HABs) (Microcystis aeruginosa). Scanning electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, converted fluorescence microscope, plasma-atomic emission spectrometry, and Zetasizer were used to study the flocculation mechanism of modified vermiculite. It was found that the vermiculite modified with hydrochloric acid could coagulate algae cells through charge neutralization, chemical bridging, and netting effect. The experimental results show that the efficiency of flocculation can be notably improved by modified vermiculite. Ninety-eight per cent of algae cells in algae solution could be removed within 10 min after the addition ofmodified vermiculite clay. The method that removal of HABs with modified vermiculite is economical with high efficiency, and more research is needed to assess their ecological impacts before using in practical application.

  6. Evaluation of filamentous green algae as feedstocks for biofuel production.

    PubMed

    Zhang, Wei; Zhao, Yonggang; Cui, Binjie; Wang, Hui; Liu, Tianzhong

    2016-11-01

    Compared with unicellular microalgae, filamentous algae have high resistance to grazer-predation and low-cost recovery in large-scale production. Green algae, as the most diverse group of algae, included numerous filamentous genera and species. In this study, records of filamentous genera and species in green algae were firstly censused and classified. Then, seven filamentous strains subordinated in different genera were cultivated in bubbled-column to investigate their growth rate and energy molecular (lipid and starch) capacity. Four strains including Stigeoclonium sp., Oedogonium nodulosum, Hormidium sp. and Zygnema extenue were screened out due to their robust growth. And they all could accumulate triacylglycerols and starch in their biomass, but with different capacity. After nitrogen starvation, Hormidium sp. and Oedogonium nodulosum respectively exhibited high capacity of lipid (45.38% in dry weight) and starch (46.19% in dry weight) accumulation, which could be of high potential as feedstocks for biodiesel and bioethanol production.

  7. Photobiological hydrogen production in green algae and photosynthetic bacteria

    SciTech Connect

    Greenbaum, E.

    1986-01-01

    We have shown that, under appropriate physiological conditions, certain freshwater and marine green algae are capable of splitting water to molecular hydrogen and oxygen in a sustained steady-state reaction. In these algae, the gaseous-fuel-producing reaction can be driven by light throughout the visible portion of the solar emission spectrum, including the long wavelength (red) 700-nm region. No external energy sources are required.

  8. Algae Reefs in Shark Bay, Western Australia, Australia

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Numerous algae reefs are seen in Shark Bay, Western Australia, Australia (26.0S, 113.5E) especially in the southern portions of the bay. The south end is more saline because tidal flow in and out of the bay is restricted by sediment deposited at the north and central end of the bay opposite the mouth of the Wooramel River. This extremely arid region produces little sediment runoff so that the waters are very clear, saline and rich in algae.

  9. An overview of algae biofuel production and potential environmental impact.

    PubMed

    Menetrez, Marc Y

    2012-07-01

    Algae are among the most potentially significant sources of sustainable biofuels in the future of renewable energy. A feedstock with virtually unlimited applicability, algae can metabolize various waste streams (e.g., municipal wastewater, carbon dioxide from industrial flue gas) and produce products with a wide variety of compositions and uses. These products include lipids, which can be processed into biodiesel; carbohydrates, which can be processed into ethanol; and proteins, which can be used for human and animal consumption. Algae are commonly genetically engineered to allow for advantageous process modification or optimization. However, issues remain regarding human exposure to algae-derived toxins, allergens, and carcinogens from both existing and genetically modified organisms (GMOs), as well as the overall environmental impact of GMOs. A literature review was performed to highlight issues related to the growth and use of algal products for generating biofuels. Human exposure and environmental impact issues are identified and discussed, as well as current research and development activities of academic, commercial, and governmental groups. It is hoped that the ideas contained in this paper will increase environmental awareness of issues surrounding the production of algae and will help the algae industry develop to its full potential. PMID:22681590

  10. Development of Green Fuels From Algae - The University of Tulsa

    SciTech Connect

    Crunkleton, Daniel; Price, Geoffrey; Johannes, Tyler; Cremaschi, Selen

    2012-12-03

    The general public has become increasingly aware of the pitfalls encountered with the continued reliance on fossil fuels in the industrialized world. In response, the scientific community is in the process of developing non-fossil fuel technologies that can supply adequate energy while also being environmentally friendly. In this project, we concentrate on green fuels which we define as those capable of being produced from renewable and sustainable resources in a way that is compatible with the current transportation fuel infrastructure. One route to green fuels that has received relatively little attention begins with algae as a feedstock. Algae are a diverse group of aquatic, photosynthetic organisms, generally categorized as either macroalgae (i.e. seaweed) or microalgae. Microalgae constitute a spectacularly diverse group of prokaryotic and eukaryotic unicellular organisms and account for approximately 50% of global organic carbon fixation. The PI's have subdivided the proposed research program into three main research areas, all of which are essential to the development of commercially viable algae fuels compatible with current energy infrastructure. In the fuel development focus, catalytic cracking reactions of algae oils is optimized. In the species development project, genetic engineering is used to create microalgae strains that are capable of high-level hydrocarbon production. For the modeling effort, the construction of multi-scaled models of algae production was prioritized, including integrating small-scale hydrodynamic models of algae production and reactor design and large-scale design optimization models.

  11. Extraction of mercury from ground-water using immobilized algae

    SciTech Connect

    Barkley, N.P.

    1991-01-01

    Bio-recovery Systems Inc., conducted a project under the Emerging Technology portion of the United States Environmental Protection Agency's (EPAs) Superfund Innovative Technology Evaluation (SITE) Program to evaluate the ability of immobilized algae to absorb mercury from contaminated groundwater in laboratory studies and pilot-scale field tests. Algae biomass was incorporated in a permeable polymeric matrix. The product, AlgaSORB, packed into absorption columns, exhibited excellent flow characteristics, and functioned as a 'biological' ion exchange resin. A sequence of eleven laboratory tests demonstrated the ability of the product to absorb mercury from groundwater that contained high levels of total dissolved solids and hard water components. However, use of a single AlgaSORB preparation yielded non-repeatable results with samples collected at different times of the year. The strategy of extracting the groundwater through two columns containing different times of the year. The strategy of extracting the groundwater through two columns containing different preparations of AlgaSORB was developed and proved successful in laboratory and pilot-scale field tests. Field test results indicate that AlgaSORB could be economically competitive with ion exchange resins for removal of mercury, with the advantage that hardness and other dissolved solids do not appear to compete with heavy metals for binding capacity. (Copyright (c) 1991--Air and Waste Management Association.)

  12. Modelling the effect of fluctuating herbicide concentrations on algae growth.

    PubMed

    Copin, Pierre-Jean; Coutu, Sylvain; Chèvre, Nathalie

    2015-03-01

    Herbicide concentrations fluctuate widely in watercourses after crop applications and rain events. The level of concentrations in pulses can exceed the water chronic quality criteria. In the present study, we proposed modelling the effects of successive pulse exposure on algae. The deterministic model proposed is based on two parameters: (i) the typical growth rate of the algae, obtained by monitoring growth rates of several successive batch cultures in growth media, characterizing both the growth of the control and during the recovery periods; (ii) the growth rate of the algae exposed to pulses, determined from a dose-response curve obtained with a standard toxicity test. We focused on the herbicide isoproturon and on the freshwater alga Scenedesmus vacuolatus, and we validated the model prediction based on effect measured during five sequential pulse exposures in laboratory. The comparison between the laboratory and the modelled effects illustrated that the results yielded were consistent, making the model suitable for effect prediction of the herbicide photosystem II inhibitor isoproturon on the alga S. vacuolatus. More generally, modelling showed that both pulse duration and level of concentration play a crucial role. The application of the model to a real case demonstrated that both the highest peaks and the low peaks with a long duration affect principally the cell density inhibition of the alga S. vacuolatus. It is therefore essential to detect these characteristic pulses when monitoring of herbicide concentrations are conducted in rivers. PMID:25499055

  13. An overview of algae biofuel production and potential environmental impact.

    PubMed

    Menetrez, Marc Y

    2012-07-01

    Algae are among the most potentially significant sources of sustainable biofuels in the future of renewable energy. A feedstock with virtually unlimited applicability, algae can metabolize various waste streams (e.g., municipal wastewater, carbon dioxide from industrial flue gas) and produce products with a wide variety of compositions and uses. These products include lipids, which can be processed into biodiesel; carbohydrates, which can be processed into ethanol; and proteins, which can be used for human and animal consumption. Algae are commonly genetically engineered to allow for advantageous process modification or optimization. However, issues remain regarding human exposure to algae-derived toxins, allergens, and carcinogens from both existing and genetically modified organisms (GMOs), as well as the overall environmental impact of GMOs. A literature review was performed to highlight issues related to the growth and use of algal products for generating biofuels. Human exposure and environmental impact issues are identified and discussed, as well as current research and development activities of academic, commercial, and governmental groups. It is hoped that the ideas contained in this paper will increase environmental awareness of issues surrounding the production of algae and will help the algae industry develop to its full potential.

  14. Radionuclides and trace metals in eastern Mediterranean Sea algae.

    PubMed

    Al-Masri, M S; Mamish, S; Budier, Y

    2003-01-01

    Three types of sea alga distributed along the Syrian coast have been collected and analyzed for radioactivity and trace elements. Results have shown that (137)Cs concentrations in all the analyzed sample were relatively low (less than 1.2 Bq kg(-1) dry weight) while the levels of naturally occurring radionuclides, such as (210)Po and (210)Pb, were found to be high in most samples; the highest observed value (27.43 Bq kg(-1) dry weight) for (210)Po being in the red Jania longifurca alga. In addition, most brown alga species were also found to accumulate (210)Po, which indicates their selectivity to this isotope. On the other hand, brown alga (Cystoseira and Sargassum Vulgare) have shown a clear selectivity for some trace metals such as Cr, As, Cu and Co, this selectivity may encourage their use as biomonitor for pollution by trace metals. Moreover, the red alga species were found to contain the highest levels of Mg while the brown alga species were found to concentrate Fe, Mn, Na and K and nonmetals such as Cl, I and Br. PMID:12660047

  15. Feeding preferences of mesograzers on aquacultured Gracilaria and sympatric algae

    PubMed Central

    Cruz-Rivera, Edwin; Friedlander, Michael

    2011-01-01

    While large grazers can often be excluded effectively from algal aquaculture operations, smaller herbivores such as small crustaceans and gastropods may be more difficult to control. The susceptibility of three Gracilaria species to herbivores was evaluated in multiple-choice experiments with the amphipod Ampithoe ramondi and the crab Acanthonyx lunulatus. Both mesograzers are common along the Mediterranean coast of Israel. When given a choice, the amphipod preferred to consume Gracilaria lemaneiformis significantly more than either G. conferta or G. cornea. The crab, however, consumed equivalent amounts of G. lemaneiformis and G. conferta, but did not consume G. cornea. Organic content of these algae, an important feeding cue for some mesograzers, could not account for these differences. We further assessed the susceptibility of a candidate species for aquaculture, G. lemaneiformis, against local algae, including common epiphytes. When given a choice of four algae, amphipods preferred the green alga Ulva lactuca over Jania rubens. However, consumption of U. lactuca was equivalent to those of G. lemaneiformis and Padina pavonica. In contrast, the crab showed a marked and significant preference for G. lemaneiformis above any of the other three algae offered. Our results suggest that G. cornea is more resistant to herbivory from common mesograzers and that, contrary to expectations, mixed cultures or epiphyte growth on G. lemaneiformis cannot reduce damage to this commercially appealing alga if small herbivores are capable of recruiting into culture ponds. Mixed cultures may be beneficial when culturing other Gracilaria species. PMID:22711945

  16. Phosphorus-limited growth of a green alga and a blue-green alga

    SciTech Connect

    Lang, D.S.; Brown, E.J.

    1981-12-01

    The phosphorus-limited growth kinetics of the chlorophyte Scenedesmus quadricauda and the cyanophyte Synechococcus Nageli were studied by using batch and continuous culturing techniques. The steady-state phosphate transport capability and the phosphorus storage capacity is higher in S. Nageli than in S. quadricauda. Synechococcus Nageli can also deplete phosphate to much lower levels than can S. quadricauda. These results, along with their morphological characteristics, were used to construct partial physiological profiles for each organism. The profiles indicate that this unicellular cyanophyte (cyanobacterium) is better suited for growth in phosphorus-limited oligotrophic niches than is this chlorophyte (green alga). (Refs. 44).

  17. Comparative Transcriptome Analysis of Four Prymnesiophyte Algae

    PubMed Central

    Koid, Amy E.; Liu, Zhenfeng; Terrado, Ramon; Jones, Adriane C.; Caron, David A.; Heidelberg, Karla B.

    2014-01-01

    Genomic studies of bacteria, archaea and viruses have provided insights into the microbial world by unveiling potential functional capabilities and molecular pathways. However, the rate of discovery has been slower among microbial eukaryotes, whose genomes are larger and more complex. Transcriptomic approaches provide a cost-effective alternative for examining genetic potential and physiological responses of microbial eukaryotes to environmental stimuli. In this study, we generated and compared the transcriptomes of four globally-distributed, bloom-forming prymnesiophyte algae: Prymnesium parvum, Chrysochromulina brevifilum, Chrysochromulina ericina and Phaeocystis antarctica. Our results revealed that the four transcriptomes possess a set of core genes that are similar in number and shared across all four organisms. The functional classifications of these core genes using the euKaryotic Orthologous Genes (KOG) database were also similar among the four study organisms. More broadly, when the frequencies of different cellular and physiological functions were compared with other protists, the species clustered by both phylogeny and nutritional modes. Thus, these clustering patterns provide insight into genomic factors relating to both evolutionary relationships as well as trophic ecology. This paper provides a novel comparative analysis of the transcriptomes of ecologically important and closely related prymnesiophyte protists and advances an emerging field of study that uses transcriptomics to reveal ecology and function in protists. PMID:24926657

  18. Microfluidic one-way streets for algae

    NASA Astrophysics Data System (ADS)

    Dunkel, Jorn; Kantsler, Vasily; Polin, Marco; Goldstein, Raymond E.

    2012-02-01

    Controlling locomotion and transport of microorganisms is a key challenge in the development of future biotechnological applications. Here, we demonstrate the use of optimized microfluidic ratchets to rectify the mean swimming direction in suspensions of the unicellular green alga Chlamydomonas reinhardtii, which is a promising candidate for the photosynthetic production of hydrogen. To assess the potential of microfluidic barriers for the manipulation of algal swimming, we studied first the scattering of individual C. reinhardtii from solid boundaries. High-speed imaging reveals the surprising result that these quasi-spherical ``puller''-type microswimmers primarily interact with surfaces via direct flagellar contact, whereas hydrodynamic effects play a subordinate role. A minimal theoretical model, based on run-and-turn motion and the experimentally measured surface-scattering law, predicts the existence of optimal wedge-shaped ratchets that maximize rectification of initially uniform suspensions. We confirm this prediction in experimental measurements with different geometries. Since the mechano-elastic properties of eukaryotic flagella are conserved across many genera, we expect that our results and methods are applicable to a broad class of biflagellate microorganisms.

  19. Mixotrophy in red tide algae raphidophytes.

    PubMed

    Jeong, Hae Jin

    2011-01-01

    Marine raphidophytes are common red tide organisms that are distributed worldwide. They are known to be harmful to other plankton and fish and have often caused large-scale fish mortality in many countries. Thus, the population dynamics of raphidophytes is a critical concern for scientists, the aquaculture industry, and government officers from many countries. Raphidophyte growth and mortality should be investigated to understand bloom dynamics. Raphidophytes were thought to be exclusively autotrophic organisms. However, several recent studies have revealed that raphidophytes are able to feed on heterotrophic and autotrophic bacteria, i.e. raphidophytes are mixotrophic algae. Further, high-resolution video microscopy has revealed the mechanism by which raphidophytes feed on bacteria, which involves capturing prey cells in the mucus excreted by mucocysts and engulfing the cells through mucocysts. These discoveries may influence the conventional view on both raphidophyte bloom dynamics and plankton energy flow and carbon cycling. In the present study, I review prey, feeding mechanisms, and ingestion rates of mixotrophic marine raphidophytes. In addition, I examine the ecological significance of raphidophyte mixotrophy.

  20. Comparative transcriptome analysis of four prymnesiophyte algae.

    PubMed

    Koid, Amy E; Liu, Zhenfeng; Terrado, Ramon; Jones, Adriane C; Caron, David A; Heidelberg, Karla B

    2014-01-01

    Genomic studies of bacteria, archaea and viruses have provided insights into the microbial world by unveiling potential functional capabilities and molecular pathways. However, the rate of discovery has been slower among microbial eukaryotes, whose genomes are larger and more complex. Transcriptomic approaches provide a cost-effective alternative for examining genetic potential and physiological responses of microbial eukaryotes to environmental stimuli. In this study, we generated and compared the transcriptomes of four globally-distributed, bloom-forming prymnesiophyte algae: Prymnesium parvum, Chrysochromulina brevifilum, Chrysochromulina ericina and Phaeocystis antarctica. Our results revealed that the four transcriptomes possess a set of core genes that are similar in number and shared across all four organisms. The functional classifications of these core genes using the euKaryotic Orthologous Genes (KOG) database were also similar among the four study organisms. More broadly, when the frequencies of different cellular and physiological functions were compared with other protists, the species clustered by both phylogeny and nutritional modes. Thus, these clustering patterns provide insight into genomic factors relating to both evolutionary relationships as well as trophic ecology. This paper provides a novel comparative analysis of the transcriptomes of ecologically important and closely related prymnesiophyte protists and advances an emerging field of study that uses transcriptomics to reveal ecology and function in protists.