16,451 research outputs found
Global expression analysis of the brown alga Ectocarpus siliculosus (Phaeophyceae) reveals large-scale reprogramming of the transcriptome in response to abiotic stress
Get PDFDittami SM, Scornet D, Petit J-L, et al. Global expression analysis of the brown alga Ectocarpus siliculosus (Phaeophyceae) reveals large-scale reprogramming of the transcriptome in response to abiotic stress. Genome Biology. 2009;10(6):R66.Background: Brown algae (Phaeophyceae) are phylogenetically distant from red and green algae and an important component of the coastal ecosystem. They have developed unique mechanisms that allow them to inhabit the intertidal zone, an environment with high levels of abiotic stress. Ectocarpus siliculosus is being established as a genetic and genomic model for the brown algal lineage, but little is known about its response to abiotic stress. Results: Here we examine the transcriptomic changes that occur during the short term acclimation of E. siliculosus to three different abiotic stress conditions (hyposaline, hypersaline and oxidative stress). Our results show that almost 70% of the expressed genes are regulated in response to at least one of these stressors. Although there are several common elements with terrestrial plants, such as repression of growth-related genes, switching from primary production to protein and nutrient recycling processes, and induction of genes involved in vesicular trafficking, many of the stress-regulated genes are either not known to respond to stress in other organisms or are have been found exclusively in E. siliculosus. Conclusions: This first large-scale transcriptomic study of a brown alga demonstrates that, unlike terrestrial plants, E. siliculosus undergoes extensive reprogramming of its transcriptome during the acclimation to mild abiotic stress. We identify several new genes and pathways with a putative function in the stress response and thus pave the way for more detailed investigations of the mechanisms underlying the stress tolerance of brown algae
Atmospheres of brown dwarfs
No full textChH highlights financial support of the European Community under the FP7 by an ERC starting grant. SLC acknowledges financial support of University of LeicesterBrown Dwarfs are the coolest class of stellar objects known to date. Our present perception is that Brown Dwarfs follow the principles of star formation, and that Brown Dwarfs share many characteristics with planets. Being the darkest and lowest mass stars known makes Brown Dwarfs also the coolest stars known. This has profound implication for their spectral fingerprints. Brown Dwarfs cover a range of effective temperatures which cause brown dwarfs atmospheres to be a sequence that gradually changes from a M-dwarf-like spectrum into a planet-like spectrum. This further implies that below an effective temperature of ≲ 2800K, clouds form already in atmospheres of objects marking the boundary between M-Dwarfs and brown dwarfs. Recent developments have sparked the interest in plasma processes in such very cool atmospheres: sporadic and quiescent radio emission has been observed in combination with decaying Xray-activity indicators across the fully convective boundary.Peer reviewe
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Image 151 of Theo Brown Diaries, 1911
No full textTher Mon. April 17, 1911 Wea Fair
Shop in morning. 2.25 train
for Whitinsville. Went to
church to rehearse wedding of
Kent and Katherine. The bridesmaids
are Miss Newell. Greenhalge - Barber,
Bigelow, Parks. Hildegard-Marion
Lasell. Lois & Lolly. Ushers.
Ed. Esty. Philip Dunbar. Paul Potter.
Will Harris. C. Baker. Hebbard.
Buchlin. T. Brown. At a
dinner at Mrs JM Lasell's had
Miss Newell for a partner (4 - Harris
Dunbar - Esty & myself were in 1 room
at the C.W. Laselles
Bed 1
Reduction of hexavalent chromium with the brown seaweed Ecklonki biomass
No full textA new type of biomass, protonated brown seaweed Ecklonia sp., was used for the removal of Cr(VI). When synthetic wastewater containing Cr(VI)was placed in contact with the biomass, the Cr(VI) was completely reduced to Cr(III). The converted Cr(III) appeared in the solution phase or was partly bound to the biomass. The Cr(VI) removal efficiency was always 100% in the pH range of this study (pH 1 similar to 5). Furthermore, the Cr(VI) reduction was independent of the Cr(III) concentration, the reaction product, suggesting that the reaction was an irreversible process under our conditions. Proton ions were consumed in the ratio of 1.15 +/- 0.02 mol of protons/mol of Cr(VI), and the rate of Cr(VI) reduction increased with decreasing the pH. An optimum pH existed for the removal efficiency of total chromium (Cr(VI) plus Cr(III)), but this increased with contact time, eventually reaching approximately pH 4 when the reaction was complete. The electrons required for the Cr(VI) reduction also caused the oxidation of the organic compounds in the biomass. One gram of the biomass could reduce 4.49 +/- 0.12 mmol of Cr(VI). From a practical viewpoint, the abundant and inexpensive Ecklonia biomass could be used for the conversion of toxic Cr(VI) into less toxic or nontoxic Cr(III).X11213sciescopu
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Image 171 of Theo Brown Diaries, 1933
No full textJune 14 WEDNESDAY 165
Clear
[Signatures: MG Healey
Frank Silloway
Elmer McCormick
JM Duncan
Charles Deere Wiman
Willard D Hosford
C.M.Heald
John Clapper.
C.R.White
H.M.Park
L.A. Paradise
J.S. Molstad.
George P. Schutz
C.B. Stone
W.H. Biloss
R.R. Laurie
R.H. White
B.J. Kough
Max Sklowsky
L.A. Rowland
Theo Brown
F.Z. Kirby
A.E.Randall]
A.H. HEAD H.B.MCKAHIN
At Harvey Hess farm allday at meeting
about tractors.
Demonstrated 6X with 2 & 4 row cultivator,
lister, lister cultivator,
#4 plow etc. Later at general discussion the plan of
making a 16HP GP. tractor and a 36 HP.
Sther was some desire for more horse power
from Healey.
Power lift wanted by everyone.
[Photograph: Men at farm demonstration]
[Photograph: Worthington, Healey, McCormic, Lourie, White
Biosorption of trivalent chromium on the brown seaweed biomass
No full textBiosorption has attracted attention as a cost-effective means for the treatment of metal-bearing wastewater. However, the mechanism of metal binding is not clearly understood, and consequently, modeling of the biosorption performance is still raising debates. In this study, the biosorption of trivalent chromium was investigated with protonated brown alga Ecklonia biomass as a model system. Titration of the biomass revealed that it contains at least three types of functional groups. The Fourier transform infrared spectrometry showed that the carboxyl group was the chromium-binding site within the pH range (pH 1-5) used in this study, where chromium does not precipitate. The pKvalue and the number of carboxyl groups were estimated to be 4.6 +/- 0.1 and 2.2 +/- 0.1 mmol/g, respectively. The equilibrium sorption isotherms determined at different solution pH indicated that the uptake of chromium increased significantly with increasing pH, A model for the description of chromium biosorption was developed incorporating the hydrolysis reactions that chromium undergoes in the aquatic phase. The model was able to predict the equilibrium sorption experimental data at different pH values and chromium concentrations. In addition, the speciation of the binding site as a function of the solution pH was predicted using the model in order to visualize the distribution of chromium ionic species on the binding site.X11268sciescopu
Localization of the CHIP28 water channel in reabsorptive segments of the rat male reproductive tract
No full textAbstract: The water channel protein CHIP28 is responsible for the high constitutive plasma membrane permeability to water of erythrocytes, renal proximal tubule, and thin descending limb of Henle. The male reproductive tract is embryologically related to kidney and some segments, particularly the efferent ducts, exhibit a high rate of solute flux-dependent reabsorption of luminal fluid. To determine whether this could occur through water channels in the plasma membrane of reproductive tract epithelial cells, we used anti-CHIP28 antibodies to localize this protein by Western blotting and immunocytochemistry. Western blotting of proteins from efferent duct homogenate indicated the presence of CHIP28 in the efferent duct cells. By indirect immunofluorescence and protein A-gold immunolabeling, CHIP28 was localized to the brush-border and basolateral membranes of nonciliated cells. Ciliated cells in the same epithelium showed no plasma membrane staining for CHIP28. In accord with immunocytochemical findings, freeze-fracture of nonciliated efferent duct cells revealed a plasma membrane organization resembling that of renal proximal tubule cells that are rich in CHIP28. The anti-CHIP28 antibodies also stained plasma membranes of epithelial cells in the ampulla of the vas deferens, seminal vesicles, and prostate, but not the cells in seminiferous tubules, epididymis, and proximal parts of the vas deferens. Therefore, CHIP28 may be a principal mediator of the transmembrane water transport in absorptive epithelial cells of efferent ducts, as well as in epithelia of several other segments of the male reproductive tract that show both secretory and reabsorptive functions
Column study on Cr(VI)-reduction using the brown seaweed Ecklonia biomass
No full textThe potential use of the brown seaweed, Ecklonia, biomass as a bioreductant for reducing Cr(VI) was examined in a continuous packed-bed column. The effects of the operating parameters, such as influent Cr(VI) concentration, influent pH, biomass concentration, flow rate and temperature, on the Cr(VI) reduction were investigated. Increases in the influent Cr(VI) concentration and flow rate or a decrease in the biomass concentration inside the column led to a higher breakthrough of the Cr(VI) ions in the effluent. Particularly, the influent pH and temperature most significantly affected on the breakthrough curve of Cr(VI); a decrease in the influent pH or an increase in the temperature enhanced the Cr(VI) reduction in the column. For process application, a non-parametric model using neural network was used to predict the breakthrough curves of the column. Finally, the potential of the column packed with Ecklonia biomass for Cr(VI) detoxification was demonstrated. (c) 2006 Published by Elsevier B.V.X1122sciescopu
The SSC of the Generalised Jahangir’s Graph Jm,k and its Algebraic Characterizations
No full textIn this article, we present important combinatorial and algebraicproperties of spanning simplicial complex (SSC) of the generalised Jahangir’sgraph Jm,k. We describe the relation to find f−vectors associatedto Δs(Jm,k) and determine the Hilbert series for the SR-ring KΔs(Jm,k).In the end, we present the associated primes of the facet ideal IF(Δs(Jm,k))and the Cohen-Macaulay characterization of the SR-ring of Δs(Jm,k).AMS (MOS) Subject Classification Codes: Primary 13-P10, Secondary 13-F20, 13-C14, 13-H10.Corresponding Author: Agha KashifKey Words: Simplicial Complexes, f-vectors, Spanning Trees, Face Ring, Hilbert Series, CohenMacaulay
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