UK PubMed Central (United Kingdom)

The response of the dissimilatory metal-reducing bacterium Shewanella alga BrY to carbon and nitrogen starvation was examined. Starvation resulted in a gradual decrease in the mean cell volume from...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

For the removal and recycle of CO2, a global warming gas, utilization of photosynthesis by micro algae is investigated. Formed micro algae are decomposed into CO2, H2O and CH4 again, which does not result in the permanent fixation. For the effective utilization of these micro algae, creation of petroleum alternate energy was tried through the co-liquefaction of micro algae with coal. Were investigated influences of the reaction temperature during the co-liquefaction and influences of catalysts, such as Fe(CO)5-S, Ru(CO)12, and Mo(CO)6-S, which are effective for the coal liquefaction. Micro algae, such as chlorella, spirulina, and littorale, and Yallourn brown coal were tested. It was found that co-liquefaction of micro algae with coal can be successfully proceeded under the same conditions as the liquefaction of coal. The oil yield obtained from the ...

UK PubMed Central (United Kingdom)

The photosynthetic activity of the green alga Scenedesmus quadricauda was investigated during synchronous growth in light/dark cycles. The rate of O₂ evolution increased...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundSenescence is integral to the flowering plant life-cycle. Senescence-like processes occur also in non-angiosperm land plants, algae and photosynthetic prokaryotes. Increasing...Full Text Available

UK PubMed Central (United Kingdom)

Electrically triggered action potentials in the giant alga Chara corallina are associated with a transient rise in the concentration of free Ca²+ in the cytoplasm (Ca²+_cyt)....Full Text Available

British Library Electronic Table of Contents (United Kingdom)

Nutritional insufficiency and toxicity are deleterious effects of phytoplankton on grazers. We hypothesize that toxic food is likely to have stronger evolutionary selective effects on grazers than nutritionally insufficient food. We explore this hypothesis in comparative studies of egg production and egg hatching of the copepod Acartia hudsonica challenged with both a toxic and a nutritionally insufficient alga. Experiments lasting 6 days, in which mixtures of different proportions of the suspect and a control alga were offered as food to female copepods, showed that the dinoflagellate Alexandrium fundyense, which bears paralytic shellfish toxins, was toxic to A. hudsonica. In contrast, the diatom Phaeodactylum tricornutum was nutritionally insufficient to A. hudsonica. In another set of e...

UK PubMed Central (United Kingdom)

Aminopeptidase II, one of the two major aminopeptidases in the giant alga Chara australis, was partially purified. Its molecular weight was estimated to be about 80,000 by gel permeation...Full Text Available

UK PubMed Central (United Kingdom)

Zygotes of fucoid algae have long been studied as a paradigm for cell polarity. Polarity is established early in the first cell cycle and is then expressed as localized growth and invariant cell division....Full Text Available

UK PubMed Central (United Kingdom)

BackgroundSelenium is a trace element performing important biological functions in many organisms including humans. It usually affects organisms in a strictly dosage-dependent manner...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The paper presents fundamental studies on natural biosorption to algae of heavy metals. The investigations were carried out by TU Berlin University in a special research project (Sfb 193, 'Biologische Behandlung industrieller und gewerblicher Abwaesser'). The chlorophyceae C. vulgaris was used as reference alga, and 38 further algae were analzyed with regard to their sorption characteristics for lead, cadmium, nickel and zinc. The most effective algae were the chlorophyceae C. salina, the cyanophyceae S. hofmani and L. taylorii. The biosorption characteristics of C. salina and L. taylorii were investigated in detail. L. taylorii was found to be exploitable successfully in a technical process, so the investigations were extended to include copper. Knowledge about the chemical processes of biosorption is important for any attempt to modify the biosorption characteristics. Experiments on ...

British Library Electronic Table of Contents (United Kingdom)

This study explores the use of photosensitizers and reactive oxygen species (ROS) to limit growth of cyanobacteria. We chose 12 phthalocyanines, tetraphenol porphyrine, and methylene blue as compounds producing singlet oxygen. Hydrogen peroxide was chosen as another source of ROS. These compounds were tested using algal toxicity tests in microplates on three cultures of green algae (Pseudokirchneriella subcapitata, Scenedesmus quadricauda, and Chlorella kessleri) and on three cultures of cyanobacteria (Synechococcus nidulans, Microcystis incerta, and Anabaena sp.). Results indicate that photosensitizers and singlet oxygen could be highly toxic for some selected phytoplankton species. Green alga Scenedesmus quadricauda was highly sensitive (EC50 = 0.07 mg/L) to compounds producing singlet o...

British Library Electronic Table of Contents (United Kingdom)

The function of selenium in an organism is mediated mostly by selenoproteins including glutathione peroxidase. Glutathione peroxidase is a potent anti-oxidative enzyme, scavenging a variety of peroxides. The green alga Scenedesmus quadricauda was used to investigate the relationship between the toxicity of selenium and the glutathione peroxidase activity. Selenium resistant strains SeIV and SeVI were synchronized and grown in high concentrations of Se (selenite or selenate). As a measure of selenium toxicity the EC50 values were determined. During growth of the untreated wild type, glutathione peroxidase activity increased slightly and then declined gradually until the end of the cell cycle. A similar pattern was observed in untreated resistant strains and when resistant strains were grown...

British Library Electronic Table of Contents (United Kingdom)

Synchronized cultures of the green alga Scenedesmus quadricauda were grown in the absence (untreated cultures) or in the presence (FdUrd-treated cultures) of 5-fluorodeoxyuridine, the specific inhibitor of nuclear DNA replication. The attainment of commitment points, at which the cells become committed to nuclear DNA replication, mitosis and cellular division, and the course of committed processes themselves were determined for cell cycle characterization. FdUrd-treated cultures showed nearly unaffected growth and attainment of the commitment points, while DNA replication(s), nuclear division(s) and protoplast fission(s) were blocked. Interestingly, the FdUrd-treated cells possessed a very high mitotic histone H1 kinase activity in the absence of any nuclear division(s). Compared with the ...

Environmental Research Database

DescriptionPhytoplankton is the collective name given to the microscopic floating plants in seas and lakes. Under certain conditions, the abundance of phytoplankton as a whole or of one or more species in particular, can reach a magnitude at which it is visible through discolouration of the sea. Some of these blooms because of the colour of the water have been called 'Red Tides'. Blooms of some 300 species of the phytoplankton are known as Harmful Algal Bloom (HAB) species in recognition of their poten [continued...

Energy Technology Data Exchange (ETDEWEB)

Recent studies indicate that [Fe]-hydrogenases and H{sub 2} metabolism are widely distributed among green algae. The enzymes are simple structured and catalyze H{sub 2} evolution with similar rates than the more complex [Fe]-hydrogenases from bacteria. Different green algal species developed diverse strategies to survive under sulfur deprivation. Chlamydomonas reinhardtii evolves large quantities of hydrogen gas in the absence of sulfur. In a sealed culture of C. reinhardtii, the photosynthetic O{sub 2} evolution rate drops below the rate of respiratory O{sub 2} consumption due to a reversible inhibition of photosystem II, thus leading to an intracellular anaerobiosis. The algal cells survive under these anaerobic conditions by switching their metabolism to a kind of photo-fermentation. Although possessing a functional [Fe]-hydrogenase gene, the cells of Scenedesmus obliquus produce no significant amounts of H{sub 2} under S-depleted conditions. Biochemical ...

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This study focused on the biosorption of total chromium onto red algae (Ceramium virgatum) biomass from aqueous solution. Experimental parameters affecting biosorption process such as pH, contact time, biomass dosage and temperature were studied. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherms. Langmuir model fitted the equilibrium data better than the Freundlich isotherm. The biosorption capacity of C. virgatum biomass for total chromium was found to be 26.5 mg/g at pH 1.5 and 10 g/L biomass dosage, 90 min equilibrium time and 20 deg. C. From the D-R isotherm model, the mean free energy was calculated as 9.7 kJ/mol, indicating that the biosorption of total chromium was taken place by chemisorption. The calculated thermodynamic parameters ({delta}G{sup o}, {delta}H{sup o}and {delta}S{sup o}) showed that the biosorption of total chromium onto C. virgatum biomass was feasible, spontaneous and exothermic at ...

International Nuclear Information System (INIS)

A laboratory stream consisting of two stream sections interrupted by two pools was filled with a mixture of tap water and organically enriched water from rivers nearby. Bottom sediment material, Potamogeton pectinatus, macro-invertebrate organisms, as well as the mosquito fish, Aplocheilichthys johnstonii were collected from rivers around Johannesburg and introduced into the laboratory stream. After initial acclimatization, the distribution of the isotope "3"2P through this laboratory stream was followed. Absorption of this isotope by benthic algae, Potamogeton pectinatus, several macro-invertebrate organisms as well as Aplocheilichthys johnstonii was recorded.

Science.gov (United States)

Biomass can provide a substantial energy source. Liquids are preferred for use as transportation fuels because of their high energy density and handling ease and safety. Liquid fuel production from biomass can be accomplished by any of several different processes including hydrolysis and fermentation of the carbohydrates to alcohol fuels, thermal gasification and synthesis of alcohol or hydrocarbon fuels, direct extraction of biologically produced hydrocarbons such as seed oils or algae lipids, or direct thermochemical conversion of the biomass to liquids and catalytic upgrading to hydrocarbon fuels. This report discusses direct thermochemical conversion to achieve biomass liquefaction and the requirements for wastewater treatment inherent in such processing. 21 refs.

Energy Technology Data Exchange (ETDEWEB)

The photosynthetic response to light of epiphytic algae from Lake Wingra, Wisconsin was determined monthly during the 1978 and 1979 growing seasons.A /sup 14/C technique was developed for measurement of photosynthesis of the intact epiphyte community which was then removed by shaking. The photosynthetic rate at low light, ..cap alpha.., varied from 5.56 to 18.26 ..mu..g C (mg Chl a)/sup -1/ h/sup -1/ (..mu..Em/sup -2/s/sup -1/)/sup -1/ while P/sup B//sub max/, the photosynthetic rate at light saturation, ranged from 1.0 to 2.6 mg C (mg Chl a)/sup -1/ h/sup -1/. During 1979, variations in ..cap alpha.. and P/sup B//sub max/ followed the sun-shade model for photosynthetic adaptation: P/sup B//sub max/ was highest in summer and lowest in spring and fall, while ..cap alpha.. followed the opposite pattern. Patterns in ..cap alpha.. and P/sup B//sub max/ for 1978 were less apparent. During 1979, P/sup B//sub max/ was significantly correlated with both temperature and ...

Energy Technology Data Exchange (ETDEWEB)

The general principles of Cu(II) binding to algal waste from agar extraction, composite material and algae Gelidium, and different modelling approaches, are discussed. FTIR analyses provided a detailed description of the possible binding groups present in the biosorbents, as carboxylic groups (D-glucuronic and pyruvic acids), hydroxyl groups (cellulose, agar and floridean starch) and sulfonate groups (sulphated galactans). Potentiometric acid-base titrations showed a heterogeneous distribution of two major binding groups, carboxyl and hydroxyl, following the quasi-Gaussian affinity constant distribution suggested by Sips, which permitted to estimate the maximum amount of acid functional groups (0.36, 0.25 and 0.1 mmol g{sup -1}) and proton binding parameters (pK{sup '}{sub H}=5.0,5.3and4.4;m{sub H} = 0.43, 0.37, 0.33), respectively for algae Gelidium, algal waste and composite material. A non-ideal, semi-empirical, thermodynamically ...

British Library Electronic Table of Contents (United Kingdom)

The coastal ecosystem health assessment is a field of increasing importance. In this paper, a preliminary assessment of ecosystem health in Zhejiang coastal water zone was made, mainly based on remote sensing data and GIS technique. Its spatial and quantitative evaluation was facilitated by the progress of remote sensing and GIS technique development. Firstly, human activities, hydrology and ecosystem problems in the study area were discussed and analyzed. Secondly, from 4 aspects of human stress, physical, chemical and biological responses to anthropogenic activities and natural stress, several indicators such as water transparency (Secchi Disk Depth, SDD), suspended substance concentration, dissolved inorganic nitrogen, active phosphate, chlorophyll, harmful algae bloom, as well as distr...

British Library Electronic Table of Contents (United Kingdom)

Lung cancer is still difficult to treat by current chemotherapeutic procedures. We recently found that MVL, an anti-HIV lectin from blue-green algae Microcystis viridis, also has antitumor activity. The objective of this study was to investigate apoptosis-inducing activity of recombinant MVL (R-MVL) and proteomic changes in A549 cells, and to identify the molecular pathways responsible for the anti-cancer action of R-MVL. We found that R-MVL induces A549 cells apoptosis in a dose-dependent manner by using MTT assay, fluorescent microscope (FM) and flow cytometry (FCM), and the IC50 was calculated to be 24.12??g/ml. Subsequently, 7 altered proteins in R-MVL-treated A549 cells were identified, including upregulated aldehyde dehydrogenase 1 and ?-actin, and five downregulated proteins: heat s...

British Library Electronic Table of Contents (United Kingdom)

Dissolved microcystins (MCs) are regularly present in water dominated by microcystin-producing, bloom-forming cyanobacteria. In vitro experiments with environmentally feasible concentrations (5 ? 10?7 M) of the three most common microcystins, MC-LR, MC-RR, and MC-YR, revealed that they influence the metabolism of different representative phytoplanktons. At light intensities that are close to the cyanobacterial bloom environment (50??mol m?2 s?1), they produce morphological and physiological changes in both microcystin-producing and -nonproducing Microcystis aeruginosa strains and also have similar effects on the green alga Scenedesmus quadricauda that is frequently present in cyanobacterial blooms. All three microcystin variants tested induce cell aggregation, increase in cell volume, and ...

British Library Electronic Table of Contents (United Kingdom)

This work investigated the inactivation of Microcystis aeruginosa (MA) with contact glow discharge electrolysis (CGDE). The influences of applied voltage, current and treatment time on the inactivation rate were critically examined. Based on the above results, the optimal conditions were chosen to sufficiently utilize chemically active species and enhance the inactivation of MA. Under the optimal conditions (voltage: 530?V; current: 30?mA; treatment time: 20?min), the inactivation rate of algae was more than 90% within 5?days incubation after inoculating. At the same time, the concentrations of Chlorophyll-a and dehydrogenase decreased, which demonstrated that 20?min CGDE treatment could effectively inhibit the growth of MA and caused deterioration of cell integrity. The present work would...

British Library Electronic Table of Contents (United Kingdom)

The chemostat theory on two species competition has shown that the dilution rate where transition of dominance occurs - transition-dilution rate - is independent of limiting-nutrient concentration. However, we obtained the experimental data indicating that the transition-dilution rate changed with variations in limiting-ammonium concentrations, using the chemostat mixed-culture of the cyanobacterium Microcystis novacekii and the green alga Scenedesmus quadricauda. The transition-dilution rate was dependent on the concentration of limiting ammonium in the influx culture medium. We tried to simulate the experimental results. Though the dilution rate has been considered independent of nutrient concentration, we introduce the effective dilution rate that depends on nutrient concentration (ammo...

Energy Technology Data Exchange (ETDEWEB)

Experimental wetlands are being constructed on mined lands in the United States as an inexpensive alternative to conventional acid mine water treatment facilities. The US Bureau of Mines is conducting an inventory of these constructed wetlands as part of a long-term evaluative study. Preliminary results, based on the 20 sites surveyed to date, indicate that the wetlands dominated by emergent species are out-performing the Sphagnum-dominated wetlands, and that much of the water treatment is accomplished by other aspects of the wetland, including bacteria, algae, amendments and other plants. Iron concentrations as high as 85 mg/l are reduced to less than 3 mg/l after flow through the constructed wetlands. Manganese is also removed, though somewhat less efficiently. 12 refs., 1 fig., 1 tab.

Energy Technology Data Exchange (ETDEWEB)

The grey-black mudstones of the Sonehat Formation form part of the Middle Jurassic fill of the Jameson Land Basin in East Greenland. The formation is exposed in the southernmost part of the north south-trending, Mesozoic rift system in East Greenland that was part of the epeiric seaway betaveen East Greenland and Norway. Sedimentological observations of the Sortehat Formation indicate deposition in an offshore marine setting that was typically low energy and periodically oxygen-deficient but was influenced by storm currents on occasion. Detailed palynological studies of the Sortehat Formation have resulted in the definition of theee palynological assemblage zones recognised at four localities, namely Enhjoerningen Dal and Pelion (north Jameson Land), the type section at Sortehat (central Jameson Land) and Albuen at Neill Klinter along Hurry Inlet (south-east Jameson Land). In stratigraphic order, these zones are termed the Botryococcus Assemblage Zone, the Naennoceratopsis gracilis- ...

Science.gov (United States)

Ratiometric fluorescent dyes are often used to monitor free ion concentrations in vivo, especially in cells that are recalcitrant to transformation with genetically encoded fluorescent markers. Although intracellular dye distributions are often found to be cytosolic, dye localisation has often not been examined in detail. We began exploring the use of BCECF (2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein) to monitor pH in the giant alga Chara australis and discovered that younger leaf cells could be loaded using the acetoxymethyl ester of BCECF. However, we were puzzled to find in microphotometric measurements that the fluorescence ratio appeared insensitive to manipulations affecting cytosolic pH. Confocal imaging of C. australis cells loaded with BCECF showed an accumulation of the dye in two locations: (1) on the outside of the chloroplasts in irregularly shaped stationary bodies; (2) within 1-1.5 mum structures that moved rapidly with the pericellular ...

Science.gov (United States)

Electrically triggered action potentials in the giant alga Chara corallina are associated with a transient rise in the concentration of free Ca(2)+ in the cytoplasm (Ca(2)+(cyt)). The present measurements of Ca(2)+(cyt) during membrane excitation show that stimulating pulses of low magnitude (subthreshold pulse) had no perceivable effect on Ca(2)+(cyt). When the strength of a pulse exceeded a narrow threshold (suprathreshold pulse) it evoked the full extent of the Ca(2)+(cyt) elevation. This suggests an all-or-none mechanism for Ca(2)+ mobilization. A transient calcium rise could also be induced by one subthreshold pulse if it was after another subthreshold pulse of the same kind after a suitable interval, i.e., not closer than a few 100 ms and not longer than a few seconds. This dependency of Ca(2)+ mobilization on single and double pulses can be simulated by a model in which a second messenger is produced in a voltage-dependent manner. This second messenger ...

International Nuclear Information System (INIS)

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 "1"4CO_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 ...

Energy Technology Data Exchange (ETDEWEB)

Only within the past decade has the potential of metal biosorption by biomass materials been well established. For economic reasons, of particular interest are abundant biomass types generated as a waste byproduct of large-scale industrial fermentations or certain metal-binding algae found in large quantities in the sea. These biomass types serve as a basis for newly developed metal biosorption processes foreseen particularly as a very competitive means for the detoxification of metal-bearing industrial effluents. The assessment of the metal-building capacity of some new biosorbents is discussed. Lead and cadmium, for instance, have been effectively removed from very dilute solutions by the dried biomass of some ubiquitous species of brown marine algae such as Ascophyllum and Sargassum, which accumulate more than 30% of biomass dry weight in the metal. Mycelia of the industrial steroid-transforming fungi Rhizopus and Absidia are excellent ...

Energy Technology Data Exchange (ETDEWEB)

Concentrations of total arsenic (As) and individual compounds were determined in green and hawksbill turtles from Ishigaki Island, Japan. In both species, total As concentrations were highest in muscle among the tissues. Arsenobetaine was a major compound in most tissues of both turtles. High concentrations of trimethylarsine oxide were detected in hawksbill turtles. A significant negative correlation between standard carapace length (SCL), an indicator of age, and total As levels in green turtles was found. In contrast, the levels increased with SCL of hawksbill turtles. Shifts in feeding habitats with growth may account for such a growth-dependent accumulation of As. Although concentrations of As in marine sponges, the major food of hawksbill turtles are not high compared to those in algae eaten by green turtles, As concentrations in hawksbill turtles were higher than those in green turtles, indicating that hawksbill turtles may have a specific accumulation ...

Energy Technology Data Exchange (ETDEWEB)

A simple method for regeneration of filaments (clones) from spheroplasts of the cyanobacterium (blue-green alga), Anabaena variabilis, was developed and used to quantify cell growth in the presence of two antibiotics. Cells from exponential phase cultures of ATCC 29413 and M3 were harvested and incubated with lysozyme (0.12% in 0.03M K-phosphate, pH 6.8, 0.55M sorbitol; 37 C) to produce spheroplasts. The spheroplasts were washed with buffer, plated onto soft agar and incubated (18 h light: 6 hr dark, 27 C). Colonies became visible at 7 - 9 days and were monitored for times up to 21 days. The concentration of chloramphenicol which inhibited cell growth by 50% was approximately 1.8 mg ml/sup -1/ medium and the concentrations of ampicillin which inhibited cell growth by 50% were approximately 4 and 15 pg ml/sup -1/ medium for ATCC 29413 and M3, respectively. This method may be useful for genetic manipulation of cells from these and other filamentous, N/sub 2/-fixing ...

Energy Technology Data Exchange (ETDEWEB)

In the Assel'skiy and Sakmarskiy time of the lower Permian epoch, on the territory of the modern Dnieper and Donets, and Pripyatskiy Basins, there was a gulf which stretched in a northwest direction. The latter connected to the open sea in the east through the CisDonets trough. Transverse tectonic elevations divided the gulf into 5 semi-isolated reservoirs. In the Assel'skiy time, in the period of carbonate sedimentation, the development of algae, crinoids, corals and other organisms occurred. They created reef, bioherm and biostroma reconstructions. The most favorable sections for their settlement were the coastal zones of the gulf, consedimentation positive structures and transverse tectonic elevations. It is assumed that the formation of reefs, bioherms and biostromas, on the one hand, and sedimentation of evaporites on the other hand, are interrelated processes. The first after the next marine transgression during their growth was a greater ...

Energy Technology Data Exchange (ETDEWEB)

The Sunoco Felda oil trend of the South Florida basin has been a prolific oil producer. All the oil is produced from the Cretaceous Sunniland formation, a leached limestone bioherm. Although the producing section has been considered reefal in the literature, petrographic and biostratigraphic analyses of various cores in producing fields have determined that these deposits are composed of particles of fragmented rudist and other fauna deposited in a tidal shoal. Atop this debris an algae and gastropod section has been deposited, typical of a mound deposited on a tidal mud flat. This model is exemplified in the Sunoco Felda and West Sunoco fields and was used in exploring the Sunoco Felda trend. From the petrological analysis of these two fields and from knowledge of other wells in the basin, biostratigraphic and lithologic trends can be determined and extended offshore into the eastern Gulf of Mexico. The author stresses petrology in exploring the Sunniland ...

Science.gov (United States)

The uptake and incorporation of (/sup 3/H)adenine as a measure of total microbial (bacteria and unicellular algae) nucleic acid synthesis depends on the validity of several assumptions. A unique characteristic of the (/sup 3/H)adenine method is the ability to measure the specific radioactivity (nCi pmol/sup -1/) of the immediate precursor pool of the adenine incorporated into nucleic acids. This measurement permits correction for isotope dilution when the added radiotracer mixes with exogenous pools of structurally related compounds before uptake and with endogenous pools after transport into the cells. The immediate precursors to (/sup 3/H)adenine incorporation into cellular RNA and DNA are ATP and dATP. Since the intracellular dATP pool is in isotopic equilibrium with the ATP pool, one can determine the specific radioactivity of both precursor pools by measuring that of the intracellular ATP pool. If the specific activity of the precursor pool is not measured, ...

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The Permian San Andres Formation of late Leonardian-early Guadalupian age is a significant hydrocarbon producer and crops out over a large area in south-central New Mexico. However, since its definition in 1909, the age and depositional environment of this unit have been questioned. In 1971 in Pecos County, Vincent Kelly divided the unit into three members: Rio Bonito, Bonney Canyon, and Fourmile Draw. The lowest member, although named for the Rio Bonito, has a type section designated at Sunset along U.S. Highway 70/380. Two miles east of Sunset, near Riverside, on the Rio Bonito, the Rio Bonito Member is exposed in a long series of roadcuts. Petrographic investigation of these rocks reveals an alternating sequence of high to low-energy intertidal to subtidal facies marked by oolitic and fossiliferous dolocalcarenite interbedded with dolomitic mudstone. The unit has been recrystallized and stylolites are abundant, as is dolomite and nodular mosaic anhydrite. These alternating units ...

Energy Technology Data Exchange (ETDEWEB)

Pretreatment of biosorbents have been suggested to modify the surface characteristics which could improve biosorption process. Stable cesium biosorption was studied in continuous fixed-bed column by chemically modified biosorbents. Two kinds of brown algae (Sargassum glaucescens and Cystoseira indica) were treated with chemical agents including formaldehyde (FA), glutaraldehyde (GA), potassium hexacyanoferrate (HCF), FA and HCF, and GA and HCF. The highest biosorption capacity (BC) was obtained from C. indica treated with FA (63.5 mg Cs/g biomass) and S. glaucescens treated with FA and HCF (62 mg Cs/g biomass). To study the effect of the best treatments on the BC, the concentration of each treatment agent was decreased. With decreasing FA agent for C. indica treatment, the BC dropped. Treatment of 1 g S. glaucescens biomass with 2.2 g FA and then 0.18 g HCF resulted in the highest BC (73.08 mg Cs/g dry biomass) which was 35.8 times higher than intact S. ...

Energy Technology Data Exchange (ETDEWEB)

This project is concerned with the structure and function of the unique antenna system found in the green photosynthetic bacteria. The antenna system in these organisms is contained within a vesicle known as a chlorosome, which is attached to the cytoplasmic side of the cell membrane. Additional antenna pigments and reaction centers are contained in integral membrane proteins. Energy absorbed by the bacteriochlorophyll c (BChl c) pigments in the chlorosome is transferred via a ``baseplate`` array of BChl a antenna pigments into the membrane and to the reaction center. This system is similar in some respects to the phycobilisome antenna system found in cyanobacteria and some types of algae, in that a membrane-associated structure absorbs light and transfers it to the membrane where conversion to chemical energy takes place. However, the overall structure, the type of pigments utilized and the nature of the proteins in these two types of membrane-associated antenna ...

Science.gov (United States)

The giant alga Chara corallina generates action potentials (APs) in response to mechanical stimulation, injury, or direct electrical stimulation. Students examine the waveform characteristics of these APs using standard intracellular recording techniques. Intracellular recording is easier than with neurons because of the large size of the Chara cell. Students observe very negative resting potentials (up to -250 mV), large AP amplitudes with depolarizing peaks approaching 0 mV, AP durations of seconds, and refractory periods up to several minutes. Students calculate Nernst potentials for the ions distributed across the Chara cell membrane to hypothesize the ions responsible for the resting potential and for the depolarizing phase of the AP. These calculations suggest that K+ is responsible for the resting potential and that Ca2+ influx and Ca2+-activated Cl- efflux are responsible for depolarizing phases of the AP, which they are. Comparison of the Chara AP ...

Energy Technology Data Exchange (ETDEWEB)

In the third quarterly report adsorption of heavy metals ions such as Cu(II) and Cr(VI) onto soils drawn from the laboratory-type wetland was shown to be weak. Secondly, it was shown that modified-clays did adsorb Cr(VI) ions strongly at pH 4.5. Further, studies on the pH dependence of the adsorption of {beta}-naphthoic acid, (NA), a well-documented contaminant in many oil and gas well waste waters onto modified-clays were undertaken and it was shown that uptake of NA by modified-clays was of the high affinity type at pH 4.5 and 7.0, but weak at pH 9.0. Adsorption of heavy metal ions, Cu{sup 2+}, and Cr(VI) onto algae, a proposed wetland amendment, was carried out and the results were presented and discussed in the fourth quarterly report. Uptake of NA by the soil component of the laboratory-type wetland was monitored as a function of pH. This quarterly report presents results from studies on the uptake of phenol and {beta}-naphthoic acid by laboratory-type ...

Science.gov (United States)

An interest in electronic materials has led me to investigate new synthetic approaches to III-V' type semiconducting (13-15, current IUPAC designation for B and N groups in the Periodic Table) and magnetic (3-15) compounds. It is now possible to prepare binary (GaAs and GdP) and ternary mixed-metal (Al[sub x]Ga[sub 1-x]As) and mixed-pnictide (GaP[sub x]As[sub 1-x]) compounds in seconds from rapid, low-temperature-initiated metathesis reactions between a metal (III) trihalide and a trisodium pnictide, exemplified by MX[sub 3] + Na[sub 3]Pn [yields] MPn + 3 NaX, where M is Al, Ga, In, (Al,Ga), or a lanthanide; X is F, Cl, or I; and Pn is P, As, Sb, or (P,As). The precursors are mixed together in a dry box and ignited by light grinding with a mortar and pestle, or by brief, local heating from a hot filament. These reactions are very exothermic (calculated [Delta]H[sub rxn] (GaAs) = 138 kcal/mol) and typically reach temperatures in excess of 700[degrees]C ...

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Total mercury (THg), methylmercury (MeHg) and 22 other trace elements were measured in ice algae, three species of zooplankton, mixed zooplankton samples, Arctic cod (Boreogadus saida), ringed seals (Phoca hispida) and eight species of seabirds to examine the trophodynamics of these metals in an Arctic marine food web. All samples were collected in 1998 in the Northwater Polynya (NOW) located between Ellesmere Island and Greenland in Baffin Bay. THg and MeHg were found to biomagnify through the NOW food web, based on significant positive relationships between log THg and log MeHg concentrations vs. {delta} {sup 15}N muscle and liver . The slope of these relationships for muscle THg and MeHg concentrations (slope = 0.197 and 0.223, respectively) were similar to those reported for other aquatic food webs. The food web behavior of THg and {delta} {sup 15}N appears constant, regardless of trophic state (eutrophic vs. oligotrophic), latitude (Arctic vs. tropical) or ...

Energy Technology Data Exchange (ETDEWEB)

The mechanism of cobalt uptake was investigated using cells of the giant alga Chara corallina in which it is possible to resolve separately uptake by the cell wall and actual influx across the cell membrane. The absorption of {sup 60}Co by Chara cells appeared to saturate within 2 h. but this was mainly due to rapid uptake into the cell wall which accounted for 87-92% of the total activity. Even after prolonged desorption most of the cell-associated {sup 60}Co was found on the cell wall. The intracellular distribution of absorbed {sup 60}Co was investigated by fractionating the cell into cytoplasm and vacuole. It was shown that {sup 60}Co influx to the vacuole occurs simultaneously with influx to the cytoplasm. The transported species appears to be Co{sup 2+} rather than the less charged Co(OH){sup +} or Co(O){sub 2}. {sup 60}Co influx is pH dependent (optimum pH 7-9), and is sensitive to some other divalent metals. Influx from solutions containing 1 {mu}M {sup ...

Science.gov (United States)

The objective of this paper is to reveal to what degree bio-based jet fuels (bio-jet) can reduce greenhouse gas (GHG) emissions from the US aviation sector. A model of the supply and demand chain of bio-jet involving farmers, bio-refineries, airlines, and policymakers is developed by considering factors that drive the decisions of actors (i.e. decision-makers and stakeholders) in the life cycle stages. Two kinds of feedstock are considered: oil-producing feedstock (i.e. camelina and algae) and lignocellulosic biomass (i.e. corn stover, switchgrass, and short rotation woody crops). By factoring in farmer/ feedstock producer and bio-refinery profitability requirements, land availability and suitability, as well as a time delay factor, a more realistic estimate of the level of bio-jet supply and emissions reduction can be developed under different oil price assumptions. Factors that drive bio-jet GHG emissions and unit production costs from each feedstock are ...

Energy Technology Data Exchange (ETDEWEB)

The purpose of this study was to assess the energy flux and energetic balance related to the swine production and the recycling of residues generated by the system for utilization as organic fertilizers. The experiment was carried out at Vale dos Ipes Farm, located in the city of Ouro Verde do Oeste, in the Western of Parana State. One finishing phase swine unity containing 600 animals was monitored from January to June 2005. The treatment system is composed by one steel digester with capacity for 50 m{sup 3}, one sedimentation tank, one algae tank and one bio fertilizer storage tank. The swine barn cleaning is performed by dry scratching on a daily basis. The generated residues flow by gravitation through ducts towards the digester. The duration of the hydraulic retention period was 12 days. In the calculation of energetic efficiency, the energetic component ration is the greatest energetic cost in production system of finishing phase swine, corresponding to 95% ...

Energy Technology Data Exchange (ETDEWEB)

The toxicities of 21 different herbicides to algae (Selenastrum capricornutum and Chlorella vulgaris) and to terrestrial plants (radishes, barley, and bush beans or soybeans) were compared to order to determine the feasibility of using a short-term (96-h) algal growth inhibition test for identifying chemicals having potential toxicity in a 4-week terrestrial plant bioassay. The toxicity of each test chemical, usually in combination with a commercial formulation, was evaluated at six nominal concentrations, between 0 and 100 mg/L growth medium in the algal bioassay or between 0 and 100 mg/kg substate in the terrestrial plant bioassay, in terms of both (1) the no-observed-effect concentration (NOEC), i.e., the highest concentration tested at which no significant (P < 0.05, one-sided test) reduction in algal growth rate or in terrestrial plant yield, relative to controls, was observed; and (2) the concentration at which algal growth rate or terrestrial plant yield ...

Energy Technology Data Exchange (ETDEWEB)

Biosorption of heavy metals by various biological materials has been studied extensively in the last decade due to its potential particularly in wastewater treatment. The presence of a large number of metals in industrial metal-bearing solutions makes it necessary to investigate their effect on the final metal uptake by individual biosorbent materials. Nonliving biomass of Sargassum, a brown marine alga, is capable of binding more than 10% of its dry weight in toxic cadmium ions. Although ubiquitous iron interferes with Cd uptake, only approximately 4.5% of it is sequestered (biomass dry weight). Biosorption of both metals at pH 4.5 could be described by Langmuir-type isotherms with b, the affinity-related coefficient (Cd: b = 0.015; Fe: b = 0.027). The interference of Fe with Cd uptake, and vice versa, was assessed by deriving three-dimensional equilibrium two-metal sorption isotherm surfaces, smoothed and cut to reveal the inhibition effect of Fe on biosorption ...

International Nuclear Information System (INIS)

Complete text of publication follows. Baikal is an ancient unique lake. The sweet water of Baikal is crystal clean; it concentrates oxygen and contains scarce silicon. This feature is provoked very particular interest for scientists and poses some awkward questions concerning the preservation of Baikal's ecosystem. A profound investigation of fish otholiths, animal teeth, sponges, valves of mollusks and diatom algae provides chronological information, possibility to reconstruct the events proceeding in the environment based on variations of their chemical composition. Because these study objects are small-sized, and some of them are micron-size, application of the electron-probe microanalysis turns to be quite productive. The goal of this study is to disclose performance capabilities of this method while investigating the Baikal flora and fauna. Investigations were performed by devices JCXA-733 and JXA-8200 using the electron microscope and x-ray microprobe modes. ...