scholarly journals Humin as an External Electron Mediator for Microbial Pentachlorophenol Dechlorination: Exploration of Redox Active Structures Influenced by Isolation Methods

2018 ◽  
Vol 15 (12) ◽  
pp. 2753 ◽  
Author(s):  
Duyen Minh Pham ◽  
Arata Katayama
Keyword(s):  
Structural Characteristics ◽  
Minor Component ◽  
Electron Mediator ◽  
Active Structures ◽  
Partial Structures ◽  
Redox Active ◽  
Isolation Methods ◽  
Peptidoglycan Structure ◽  
Quinone Structure ◽  
A Minor

Humin (HM) has been reported to function as an external electron mediator (EEM) in various microbial reducing reactions. In this study, the effect of isolation methods on EEM functionality and the chemical/electrochemical structures of HM were examined based on the correlation between dechlorination rates in the anaerobic HM-dependent pentachlorophenol (PCP)-dechlorinating consortium and the chemical/electrochemical structures of HM. A lack of PCP dechlorination activity suggested no EEM function in the HM samples prepared as a soluble fraction in dimethyl sulfoxide and sulfuric acid (which did not contain any electric capacitance). Other HM samples exhibited EEM functionality as shown by the dechlorination activity ranging from 0.55 to 3.48 (µmol Cl−) L−1d−1. The comparison of dechlorination activity with chemical structural characteristics suggested that HM with EEM functionalities had predominantly aliphatic and carbohydrate carbons with the partial structures C=O, O=C–N, and O=C–O. EEM functionality positively correlated with the proportion of O=C–N and O=C–O, suggesting an association between peptidoglycan structure and EEM functionality. The lack of detection of a quinone structure in one HM sample with EEM functionality and a negative correlation with aromatic or C=C carbon suggested that the mechanism containing quinone structures is a minor component for the functionality of EEM.

Protonation effects on dynamic flux properties of aqueous metal complexes

2009 ◽  
Vol 74 (10) ◽  
pp. 1543-1557 ◽  
Author(s):  
Herman P. Van Leeuwen ◽  
Raewyn M. Town
Keyword(s):  
Complex Formation ◽  
Metal Ion ◽  
Good Description ◽  
Minor Component ◽  
Outer Sphere ◽  
Metal Species ◽  
Central Metal ◽  
Inner Sphere ◽  
A Minor ◽  
Protonated Ligand

The degree of (de)protonation of aqueous metal species has significant consequences for the kinetics of complex formation/dissociation. All protonated forms of both the ligand and the hydrated central metal ion contribute to the rate of complex formation to an extent weighted by the pertaining outer-sphere stabilities. Likewise, the lifetime of the uncomplexed metal is determined by all the various protonated ligand species. Therefore, the interfacial reaction layer thickness, μ, and the ensuing kinetic flux, Jkin, are more involved than in the conventional case. All inner-sphere complexes contribute to the overall rate of dissociation, as weighted by their respective rate constants for dissociation, kd. The presence of inner-sphere deprotonated H2O, or of outer-sphere protonated ligand, generally has a great impact on kd of the inner-sphere complex. Consequently, the overall flux can be dominated by a species that is a minor component of the bulk speciation. The concepts are shown to provide a good description of experimental stripping chronopotentiometric data for several protonated metal–ligand systems.

scholarly journals Ultrastructural and Biophysical Characterization of Hepatitis C Virus Particles Produced in Cell Culture

2010 ◽  
Vol 84 (21) ◽  
pp. 10999-11009 ◽  
Author(s):  
Pablo Gastaminza ◽  
Kelly A. Dryden ◽  
Bryan Boyd ◽  
Malcolm R. Wood ◽  
Mansun Law ◽  
...  
Keyword(s):  
Cell Culture ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Structural Characteristics ◽  
Buoyant Density ◽  
Hcv Rna ◽  
Membrane Bilayer ◽  
Biophysical Characterization ◽  
Negative Stain ◽  
A Minor

ABSTRACT We analyzed the biochemical and ultrastructural properties of hepatitis C virus (HCV) particles produced in cell culture. Negative-stain electron microscopy revealed that the particles were spherical (∼40- to 75-nm diameter) and pleomorphic and that some of them contain HCV E2 protein and apolipoprotein E on their surfaces. Electron cryomicroscopy revealed two major particle populations of ∼60 and ∼45 nm in diameter. The ∼60-nm particles were characterized by a membrane bilayer (presumably an envelope) that is spatially separated from an internal structure (presumably a capsid), and they were enriched in fractions that displayed a high infectivity-to-HCV RNA ratio. The ∼45-nm particles lacked a membrane bilayer and displayed a higher buoyant density and a lower infectivity-to-HCV RNA ratio. We also observed a minor population of very-low-density, >100-nm-diameter vesicular particles that resemble exosomes. This study provides low-resolution ultrastructural information of particle populations displaying differential biophysical properties and specific infectivity. Correlative analysis of the abundance of the different particle populations with infectivity, HCV RNA, and viral antigens suggests that infectious particles are likely to be present in the large ∼60-nm HCV particle populations displaying a visible bilayer. Our study constitutes an initial approach toward understanding the structural characteristics of infectious HCV particles.

Petrography and provenance of the Marambio Group, Vega Island, Antarctica

1994 ◽  
Vol 6 (4) ◽  
pp. 517-527 ◽  
Author(s):  
Duncan Pirrie
Keyword(s):  
Late Cretaceous ◽  
Sedimentary Rocks ◽  
Clay Mineralogy ◽  
Minor Component ◽  
Source Area ◽  
Low Grade ◽  
Western Margin ◽  
Sediment Input ◽  
A Minor ◽  
Sandstone Petrography

Late Cretaceous sedimentary rocks assigned to the Santa Marta (Herbert Sound Member) and López de Bertodano (Cape Lamb and Sandwich Bluff members) formations of the Marambio Group, crop out on Cape Lamb, Vega Island. Although previous studies have recognized that these sedimentary rocks were derived from the northern Antarctic Peninsula region, the work presented here allows the provenance and palaeogeographical evolution of the region to be described in detail. On the basis of both sandstone petrography and clay mineralogy, the Herbert Sound and Cape Lamb members reflect sediment input from a low relief source area, with sand grade sediment sourced from low grade metasediments, and clay grade sediment ultimately derived from the weathering of an andesitic source area. In contrast, the Sandwich Bluff Member reflects a switch to a predominantly andesitic volcaniclastic source. However, this sediment was largely derived from older volcanic suites due to renewed source area uplift, with only a minor component from coeval volcanism. Regional uplift of both the arc terrane and the western margin of the James Ross Basin was likely during the Maastrichtian.

scholarly journals Species pattern of phosphatidylinositol from lung surfactant and a comparison of the species pattern of phosphatidylinositol and phosphatidylglycerol synthesized de novo in lung microsomal fractions

1988 ◽  
Vol 254 (1) ◽  
pp. 67-71 ◽  
Author(s):  
B Rüstow ◽  
Y Nakagawa ◽  
H Rabe ◽  
K Waku ◽  
D Kunze
Keyword(s):  
Lung Function ◽  
Molecular Species ◽  
De Novo ◽  
Lung Surfactant ◽  
Minor Component ◽  
Main Species ◽  
Surfactant Phospholipids ◽  
Species Pattern ◽  
A Minor

1. Phosphatidylinositol (PI) is a minor component of lung surfactant which may be able to replace the functionally important phosphatidylglycerol (PG) [Beppu, Clements & Goerke (1983) J. Appl. Physiol. 55, 496-502] without disturbing lung function. The dipalmitoyl species is one of the main species for both PI (14.4%) and PG (16.9%). Besides the C16:0--C16:0 species, the C16:0--C18:0, C16:0--C18:1, C16:0--C18:2 and C18:0--C18:1 species showed comparable proportions in the PG and PI fractions. These similarities of the species patterns and the acidic character of both phospholipids could explain why surfactant PG may be replaced by PI. 2. PI and PG were radiolabelled by incubation of microsomal fractions with [14C]glycerol 3-phosphate (Gro3P). For 11 out of 14 molecular species of PI and PG we measured comparable proportions of radioactivity. The radioactivity of these 11 species accounted together for more than 80% of the total. The addition of inositol to the incubation system decreased the incorporation in vitro of Gro3P into PG and CDP-DG (diacylglycerol) of lung microsomes (microsomal fractions), but did not change the distribution of radioactivity among the molecular species of PG. These results supported the idea that both acidic surfactant phospholipids may be synthesized de novo from a common CDP-DG pool in lung microsomes.

scholarly journals Recreational Harvest of Sharks and Rays in Western Australia Is Only a Minor Component of the Total Harvest

2021 ◽  
Vol 13 (11) ◽  
pp. 6215
Author(s):  
Matias Braccini ◽  
Eva Lai ◽  
Karina Ryan ◽  
Stephen Taylor
Keyword(s):  
Western Australia ◽  
Minor Component ◽  
The North ◽  
Commercial Harvest ◽  
Unknown Status ◽  
Reef Sharks ◽  
Conservation Concern ◽  
Taxonomic Groups ◽  
A Minor ◽  
Port Jackson

Sharks and rays are a global conservation concern with an increasing number of species considered at risk of extinction, mostly due to overfishing. Although the recreational harvest of sharks and rays is poorly documented and generally minimal, it can be comparable to the commercial harvest. In this study, we quantified the recreational harvest of sharks and rays in Western Australia, a region with a marine coastline greater than 20,000 km. A total of 33 species/taxonomic groups were identified, with the harvest dominated by dusky and bronze whalers, blacktip reef sharks, gummy sharks, Port Jackson sharks, wobbegongs, and rays and skates. Eighty-five percent of individuals were released with an unknown status (alive or dead). We found a latitudinal gradient of species composition, with tropical and subtropical species of the genus Carcharhinus dominating in the north and temperate species from a range of families dominating in the south. Overall, our findings showed that the recreational harvest was negligible when compared with commercial landings.

scholarly journals Rat liver alcohol dehydrogenase. Purification and properties

1971 ◽  
Vol 125 (4) ◽  
pp. 1039-1047 ◽  
Author(s):  
M J Arslanian ◽  
E Pascoe ◽  
J G Reinhold
Keyword(s):  
Molecular Weight ◽  
Alcohol Dehydrogenase ◽  
Rat Liver ◽  
Gel Filtration ◽  
Rabbit Antiserum ◽  
Minor Component ◽  
Disc Electrophoresis ◽  
Supernatant Fraction ◽  
Liver Alcohol Dehydrogenase ◽  
A Minor

Alcohol dehydrogenase (EC 1.1.1.1) from the rat liver supernatant fraction has been purified 200-fold and partially characterized. The isolation procedure involved ammonium sulphate fractionation, DEAE-Sephadex chromatography and gel filtration. The purified enzyme behaved as a homogeneous preparation as evaluated by cellulose acetate and polyacrylamide-gel disc electrophoresis. Sulphoethyl-Sephadex chromatography and immunoelectrophoresis with rabbit antiserum indicated the presence of a minor component. Rat liver alcohol dehydrogenase appears to contain 4mol of zinc/mol, has an estimated molecular weight of 65000 and consists of two subunits of similar molecular weight. Heavy-metal ions, thiol-blocking reagents, urea at concentrations below 8m, low pH (5.5) and chelating agents deactivate the enzyme but do not dissociate it into subunits. Deactivated enzyme could not be reactivated. The enzyme is strictly specific for NAD+ and has a broad specificity for alcohols, which are bound at a hydrophobic site. Inhibition occurred with the enzyme equilibrated with Zn2+ at concentrations above 0.1mm.

scholarly journals Structural defects in rat liver deoxyribonucleic acid. Endogenous single-strained regions in comparison with damage induced in vivo by a carcinogen

1979 ◽  
Vol 179 (2) ◽  
pp. 341-352 ◽  
Author(s):  
B W Stewart ◽  
P H Huang ◽  
M J Brian
Keyword(s):  
Rat Liver ◽  
Structural Damage ◽  
Deae Cellulose ◽  
Minor Component ◽  
Structural Defects ◽  
Structural Abnormality ◽  
Denaturation Kinetics ◽  
Limited Digestion ◽  
A Minor

Rat liver DNA may be separated into two fractions by stepwise elution from benzoylated-DEAE-cellulose with NaCl and caffeine solutions respectively. Other studies using bacterical and yeast DNA suggested that the first fraction contains native DNA, whereas the second may exhibit some degree of single-stranded character. In the present experiments, chromatography of DNA was monitored by labelling in vivo with [methyl-3H]thymidine in rats previously subjected to partial hepatectomy. In animals killed up to 1 h after thymidine injection, radioactivity eluted in the second fraction was inversely related to the incorporation time, being greatest when animals were killed 10 min after radioisotope injection. However, for most experiments, animals were allowed to survive 2-4 weeks after surgery before use, analysis being made on non-dividing DNA. Under these conditions, the proportion of caffeine-eluted DNA was decreased by subjecting the preparation to shear, before chromatography. A procedure that resulted in 12% of the recovered radioactivity being eluted with caffeine was adopted for experiments involving comparisons of the two DNA fractions. Under these conditions, cross-contamination could be detected by rechromatography, but this did not preclude distinction being made between the two fractions in terms of DNA structure. NaCl-eluted DNA did not bind to nitrocellulose filters. Caffeine-eluted DNA was retained by the filters and released by washing with 3mM-Tris/HCl, pH9.4. The fractions did not differ in terms of isopycnic centrifugation in CsCl. The NaCl-eluted fraction migrated as a single band in polyacrylamide gels, and this pattern was not modified by prior digestion with Neurospora crassa endonuclease. In contrast, caffeine-eluted DNA contained a minor component having a wide molecular-weight distribution and was subject to limited digestion by the endonuclease. The kinetics of denaturation of NaCi-eluted DNA in the presence of formaldehyde, in common with unfractionated DNA, were consistent with double-stranded structure. The same analysis of caffeine-eluted DNA revealed structural abnormality equivalent to two defects per 10000 base-pairs. The data are consistent with the minor fraction of rat liver DNA, separated by using benzoylated-DEAE-cellulose, containing regions of local denaturation. We previously showed that administration of the hepatocarcinogen dimethylnitrosamine is associated with an increase in the proportion of caffeine-eluted DNA. In terms of most analysis, differences between DNA fraction from nitrosamine-treated rats were similar to differences exhibited by preparations from control animals. However, structural analysis using denaturation kinetics indicated defects in both the NaCl- and caffeine-eluted DNA isolated from nitrosamine-treated rats. The two fractions differed from each other in that caffeine-eluted DNA exhibited a degree of structural damage far greater than that detected in any preparation from control animals...

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