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Acetate Oxidation Coupled To Fe(Iii) Reduction In Hyperthermophilic Microorganisms, Jason M. Tor, Kazem Kashefi, Derek Lovley
Acetate Oxidation Coupled To Fe(Iii) Reduction In Hyperthermophilic Microorganisms, Jason M. Tor, Kazem Kashefi, Derek Lovley
Derek Lovley
No hyperthermophilic microorganisms have previously been shown to anaerobically oxidize acetate, the key extracellular intermediate in the anaerobic oxidation of organic matter. Here we report that two hyperthermophiles, Ferroglobus placidus and “Geoglobus ahangari,” grow at 85°C by oxidizing acetate to carbon dioxide, with Fe(III) serving as the electron acceptor. These results demonstrate that acetate could potentially be metabolized within the hot microbial ecosystems in which hyperthermophiles predominate, rather than diffusing to cooler environments prior to degradation as has been previously proposed.
Direct And Fe(Ii) Mediated Reduction Of Technetium By Fe(Iii)-Reducing Bacteria, Jon R. Lloyd, V. A. Sole, Catherine V. Van Praagh, Derek Lovley
Direct And Fe(Ii) Mediated Reduction Of Technetium By Fe(Iii)-Reducing Bacteria, Jon R. Lloyd, V. A. Sole, Catherine V. Van Praagh, Derek Lovley
Derek Lovley
The dissimilatory Fe(III)-reducing bacterium Geobacter sulfurreducens reduced and precipitated Tc(VII) by two mechanisms. Washed cell suspensions coupled the oxidation of hydrogen to enzymatic reduction of Tc(VII) to Tc(IV), leading to the precipitation of TcO(2) at the periphery of the cell. An indirect, Fe(II)-mediated mechanism was also identified. Acetate, although not utilized efficiently as an electron donor for direct cell-mediated reduction of technetium, supported the reduction of Fe(III), and the Fe(II) formed was able to transfer electrons abiotically to Tc(VII). Tc(VII) reduction was comparatively inefficient via this indirect mechanism when soluble Fe(III) citrate was supplied to the cultures but was enhanced …
Effects Of Synchrony With Host Plant On Population Of A Spring-Feeding Lepidopteran, Joseph Elkinton, A. F. Hunter
Effects Of Synchrony With Host Plant On Population Of A Spring-Feeding Lepidopteran, Joseph Elkinton, A. F. Hunter
Joseph Elkinton
Comparisons of traits of outbreaking and nonoutbreaking leaf-eating Lepidoptera and Symphyta have shown that spring-feeding species are more likely to have outbreaks than are summer-feeding species. It has been suggested that variable synchrony with host budburst causes the population sizes of spring-feeding species to be more variable primarily because of the negative effects of older leaves on insects. While much evidence exists that leaf age can directly affect survival and reproduction of insects, few studies have looked at the population-level effects of variable phenology, and especially the potential for complex direct and indirect interactions with natural-enemy effects. To examine the …
Lack Of Production Of Electron-Shuttling Compounds Or Solubilization Of Fe(Iii) During Reduction Of Insoluble Fe(Iii) Oxide Of Geobacter Metallireducens, Derek Lovley, Kelly P. Nevin
Lack Of Production Of Electron-Shuttling Compounds Or Solubilization Of Fe(Iii) During Reduction Of Insoluble Fe(Iii) Oxide Of Geobacter Metallireducens, Derek Lovley, Kelly P. Nevin
Kelly Nevin
Studies with the dissimilatory Fe(III)-reducing microorganism Geobacter metallireducens demonstrated that the common technique of separating Fe(III)-reducing microorganisms and Fe(III) oxides with semipermeable membranes in order to determine whether the Fe(III) reducers release electron-shuttling compounds and/or Fe(III) chelators is invalid. This raised doubts about the mechanisms for Fe(III) oxide reduction by this organism. However, several experimental approaches indicated that G. metallireducens does not release electron-shuttling compounds and does not significantly solubilize Fe(III) during Fe(III) oxide reduction. These results suggest that G. metallireducens directly reduces insoluble Fe(III) oxide.
The Promoter Of The Yeast Ino4 Regulatory Gene:A Model Of The Simplest Yeast Promoter, John Lopes, Kelly A. Robinson
The Promoter Of The Yeast Ino4 Regulatory Gene:A Model Of The Simplest Yeast Promoter, John Lopes, Kelly A. Robinson
John Lopes
In Saccharomyces cerevisiae, the phospholipid biosynthetic genes are transcriptionally regulated in response to inositol and choline. This regulation requires the transcriptional activator proteins Ino4p and Ino2p, which form a heterodimer that binds to the UASINO element. We have previously shown that the promoters of the INO4 and INO2 genes are among the weakest promoters characterized in yeast. Because little is known about the promoters of weakly expressed yeast genes, we report here the analysis of the constitutive INO4 promoter. Promoter deletion constructs scanning 1,000 bp upstream of theINO4 gene identified a small region (−58 to −46) that is absolutely required …
Lack Of Production Of Electron-Shuttling Compounds Or Solubilization Of Fe(Iii) During Reduction Of Insoluble Fe(Iii) Oxide Of Geobacter Metallireducens, Kelly P. Nevin, Derek Lovley
Lack Of Production Of Electron-Shuttling Compounds Or Solubilization Of Fe(Iii) During Reduction Of Insoluble Fe(Iii) Oxide Of Geobacter Metallireducens, Kelly P. Nevin, Derek Lovley
Derek Lovley
Studies with the dissimilatory Fe(III)-reducing microorganismGeobacter metallireducens demonstrated that the common technique of separating Fe(III)-reducing microorganisms and Fe(III) oxides with semipermeable membranes in order to determine whether the Fe(III) reducers release electron-shuttling compounds and/or Fe(III) chelators is invalid. This raised doubts about the mechanisms for Fe(III) oxide reduction by this organism. However, several experimental approaches indicated that G. metallireducens does not release electron-shuttling compounds and does not significantly solubilize Fe(III) during Fe(III) oxide reduction. These results suggest that G. metallireducens directly reduces insoluble Fe(III) oxide.
Vocal Tract Function In Birdsong Production: Experimental Manipulation Of Beak Movements, Jeffrey Podos, W. J. Hoese, N. C. Boetticher, S. Nowicki
Vocal Tract Function In Birdsong Production: Experimental Manipulation Of Beak Movements, Jeffrey Podos, W. J. Hoese, N. C. Boetticher, S. Nowicki
Jeffrey Podos
Kinematic analyses have demonstrated that the extent to which a songbird's beak is open when singing correlates with the acoustic frequencies of the sounds produced, suggesting that beak movements function to modulate the acoustic properties of the vocal tract during song production. If motions of the beak are necessary for normal song production, then disrupting the ability of a bird to perform these movements should alter the acoustic properties of its song. We tested this prediction by comparing songs produced normally by white-throated sparrows and swamp sparrows with songs produced when the beak was temporarily immobilized. We also observed how …
F-Actin Is Concentrated In Nonrelease Domains At Frog Neuromuscular Junctions, Elizabeth A. Connor, A. Duneavsky
F-Actin Is Concentrated In Nonrelease Domains At Frog Neuromuscular Junctions, Elizabeth A. Connor, A. Duneavsky
Elizabeth A. Connor
To gain insight into the role of F-actin in the organization of synaptic vesicles at release sites, we examined the synaptic distribution of F-actin by using a unique synaptic preparation of frog target-deprived nerve terminals. In this preparation, imaging of the synaptic site was unobstructed by the muscle fiber cytoskeleton, allowing for the examination of hundreds of synaptic sites in their entirety in whole mounts. At target-deprived synaptic sites F-actin was distributed in a ladder-like pattern and was colocalized with β-fodrin. Surprisingly, F-actin stain, which we localized to the nerve terminal itself, did not overlap a synaptic vesicle marker, suggesting …
Performance Of Trees In The Massachusetts Planting Of The 1994 Nc-140 Peach Rootstock Trial Over Seven Growing Seasons, Wesley Autio, James Krupa, Jon Clement
Performance Of Trees In The Massachusetts Planting Of The 1994 Nc-140 Peach Rootstock Trial Over Seven Growing Seasons, Wesley Autio, James Krupa, Jon Clement
Wesley Autio
No abstract provided.
Performance Of Trees In The Massachusetts Planting Of The 1994 Nc‐140 Apple Rootstock Trial Over Seven Growing Seasons, Wesley Autio, James Krupa, Jon Clement
Performance Of Trees In The Massachusetts Planting Of The 1994 Nc‐140 Apple Rootstock Trial Over Seven Growing Seasons, Wesley Autio, James Krupa, Jon Clement
Wesley Autio
No abstract provided.
Stunted Plant 1 Mediates Effects Of Cytokinin, But Not Of Auxin, On Cell Division And Expansion In The Root Of Arabidopsis Thaliana, Tobias Baskin, G.T.S. Beemster
Stunted Plant 1 Mediates Effects Of Cytokinin, But Not Of Auxin, On Cell Division And Expansion In The Root Of Arabidopsis Thaliana, Tobias Baskin, G.T.S. Beemster
Tobias Baskin
Plants control organ growth rate by adjusting the rate and duration of cell division and expansion. Surprisingly, there have been few studies where both parameters have been measured in the same material, and thus we have little understanding of how division and expansion are regulated interdependently. We have investigated this regulation in the root meristem of the stunted plant 1(stp1) mutation of Arabidopsis, the roots of which elongate more slowly than those of the wild type and fail to accelerate. We used a kinematic method to quantify the spatial distribution of the rate and extent of cell division and expansion, …