2,223 research outputs found
Competition and coexistence of sulfate-reducing bacteria, acetogens and methanogens in a lab-scale anaerobic bioreactor as affected by changing substrate to sulfate ratio
No full textThe microbial population structure and function of natural anaerobic communities maintained in lab-scale continuously stirred tank reactors at different lactate to sulfate ratios and in the absence of sulfate were analyzed using an integrated approach of molecular techniques and chemical analysis. The population structure, determined by denaturing gradient gel electrophoresis and by the use of oligonucleotide probes, was linked to the functional changes in the reactors. At the influent lactate to sulfate molar ratio of 0.35 mol mol?1, i.e., electron donor limitation, lactate oxidation was mainly carried out by incompletely oxidizing sulfate-reducing bacteria, which formed 80–85% of the total bacterial population. Desulfomicrobium- and Desulfovibriolike species were the most abundant sulfate-reducing bacteria. Acetogens and methanogenic Archaea were mostly outcompeted, although less than 2% of an acetogenic population could still be observed at this limiting concentration of lactate. In the near absence of sulfate (i.e., at very high lactate/sulfate ratio), acetogens and methanogenic Archaea were the dominant microbial communities. Acetogenic bacteria represented by Dendrosporobacter quercicolus-like species formed more than 70% of the population, while methanogenic bacteria related to uncultured Archaea comprising about 10–15% of the microbial community. At an influent lactate to sulfate molar ratio of 2 mol mol?1, i.e., under sulfate-limiting conditions, a different metabolic route was followed by the mixed anaerobic community. Apparently, lactate was fermented to acetate and propionate, while the majority of sulfidogenesis and methanogenesis were dependent on these fermentation products. This was consistent with the presence of significant levels (40–45% of total bacteria) of D.quercicolus-like heteroacetogens and a corresponding increase of propionate-oxidizing Desulfobulbus-like sulfate-reducing bacteria (20% of the total bacteria). Methanogenic Archaea accounted for 10% of the total microbial community.BiotechnologyApplied Science
Interview with Philip Gerard
No full textInterview with Philip Gerard, author and professor of creative writing at UNCW. Here, he discusses his background and education, the founding and structure of UNCW's MFA in Creative Writing program, and the concerns of memoir and creative nonfiction
Philip Gerard, 25th Annual ODU Literary Festival
No full textPhilip Gerard has published fiction and nonfiction in numerous magazines, including New England Review, Bread Loaf Quarterly, Creative Nonfiction, Hawaii Review, Hayden\u27s Ferry Review, and The World & I. He is the author of three novels: Hatteras Light, Cape Fear Rising, Desert Kill; two books of nonfiction, Brilliant Passage...a schooning memoir and Creative Nonfiction - Researching and Crafting Stories of Real Life, and Writing a Book that Makes a Difference. His most recent book is Secret Soldiers, about the first and last battlefield deception outfit ever authorized by the U.S. Army. Gerard has written shows for public television and radio. He teaches creative writing at the University of North Carolina at Wilmington
Bacterial biofilms on gold grains-implications for geomicrobial transformations of gold
No full textThe biogeochemical cycling of gold (Au), i.e. its solubilization, transport and re-precipitation, leading to the (trans)formation of Au grains and nuggets has been demonstrated under a range of environmental conditions. Biogenic (trans)formations of Au grains are driven by (geo)biochemical processes mediated by distinct biofilm consortia living on these grains. This review summarizes the current knowledge concerning the composition and functional capabilities of Au-grain communities, and identifies contributions of key-species involved in Au-cycling. To date, community data are available from grains collected at 10 sites in Australia, New Zealand and South America. The majority of detected operational taxonomic units detected belong to the α-, β- and γ -Proteobacteria and the Actinobacteria. A range of organisms appears to contribute predominantly to biofilm establishment and nutrient cycling, some affect the mobilization of Au via excretion of Au-complexing ligands, e.g. organic acids, thiosulfate and cyanide, while a range of resident Proteobacteria, especially Cupriavidus metallidurans and Delftia acidovorans, have developed Au-specific biochemical responses to deal with Au-toxicity and reductively precipitate mobile Au-complexes. This leads to the biomineralization of secondary Au and drives the environmental cycle of Au
Identification of 16S Ribosomal DNA-Defined Bacterial Populations at a Shallow Submarine Hydrothermal Vent near Milos Island (Greece)
No full textABSTRACT
In a recent publication (S. M. Sievert, T. Brinkhoff, G. Muyzer, W. Ziebis, and J. Kuever, Appl. Environ. Microbiol. 65:3834–3842, 1999) we described spatiotemporal changes in the bacterial community structure at a shallow-water hydrothermal vent in the Aegean Sea near the isle of Milos (Greece). Here we describe identification and phylogenetic analysis of the predominant bacterial populations at the vent site and their distribution at the vent site as determined by sequencing of DNA molecules (bands) excised from denaturing gradient gels. A total of 36 bands could be sequenced, and there were representatives of eight major lineages of the domain
Bacteria. Cytophaga-Flavobacterium
and
Acidobacterium
were the most frequently retrieved bacterial groups. Less than 33% of the sequences exhibited 90% or more identity with cultivated organisms. The predominance of putative heterotrophic populations in the sequences retrieved is explained by the input of allochthonous organic matter at the vent site.
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Kant and Gerard on imagination
No full textAlexander Gerard, a schottish philosopher, is nowadays almost
forgotten, but at the time of Kant’s philosophical development he was a very
popular author and his works were translated to german. Kant mentioned Gerard
sometimes in his lectures on anthropology, particularly about genius and
imagination. A near analysis and comparing of their conception of genius and
imagination shows a significant influence of Gerard on Kant. Purpose of this
paper is to analyse this influence in the particular case of imagination and active
imagination.O filósofo escocês Alexander Gerard foi quase que inteiramente
esquecido pela história da filosofia. Mas na época em que Kant estava
desenvolvendo sua filosofia crítica, particularmente nos anos 1770, Gerard era
um autor bastante popular, tendo seus principais escritos traduzidos inclusive
para o alemão. Kant o menciona algumas vezes nas lições sobre antropologia,
permitindo assim documentar sua leitura. Este artigo procura mostrar a
influência de Gerard sobre Kant na concepção de uma imaginação ativa, peça
central da filosofia transcendental kantiana
Philip Gerard : an individual /
No full textMode of access: Internet."This first and limited edition of 'Philip Gerard, an individual,' printed for the Faculty and students of Drake University, and for the personal friends of the author, consists of five hundred copies. The number of this book is 98." Signed by author
Reconstructing embedded liberalism: John Gerard Ruggie and constructivist approaches to the study of the international trade regime
No full textIn 1982, John Gerard Ruggie published a study of the postwar international trade and monetary regimes in which he introduced the concept of ‘embedded liberalism’. A large and growing number of international trade scholars are finding Ruggie’s concept of embedded liberalism an appealing one, and it now occupies a significant place on our conceptual horizon. In this article, the author returns to Ruggie’s original article to excavate lessons which are peculiarly relevant for current trade law scholarship. He argues that Ruggie’s account of embedded liberalism usefully serves to destabilize common assumptions about the objectives and normative underpinnings of the trade regime and thereby to expand our conceptions of what a liberal trade regime might plausibly look like. On the other hand, he explains why he does not share the enthusiasm of those who see in embedded liberalism an attractive normative vision to guide WTO reform. In addition, and most importantly, the author draws attention to the constructivist theoretical framework of Ruggie’s piece. He suggests that Ruggie’s article provides a useful introduction to the central elements of constructivist thinking about international institutions and shows how attention to constructivist insights has the potential to significantly enrich and expand our understanding of the trade regime and of trade law
Office staff, Co-op
No full textThe photograph is of the co-op staff before or after its banquet at the Bank Hotel in Delta, Utah. Emil Sekerak is in the middle, wearing dark glasses. Next to him with the bow tie is Dwight Uchida, author Yoshiko Uchida\u27s father. Mr. Kanzaki from San Francisco is in the photo but it is not clear which man he is
Transcriptomic Analysis of Two Thioalkalivibrio Species Under Arsenite Stress Revealed a Potential Candidate Gene for an Alternative Arsenite Oxidation Pathway
No full textThe genus Thioalkalivibrio includes haloalkaliphilic chemolithoautotrophic sulfur-oxidizing bacteria isolated from various soda lakes worldwide. Some of these lakes possess in addition to their extreme haloalkaline environment also other harsh conditions, to which Thioalkalivibrio needs to adapt. An example is arsenic in soda lakes in eastern California, which is found there in concentrations up to 3000 mu M. Arsenic is a widespread element that can be an environmental issue, as it is highly toxic to most organisms. However, resistance mechanisms in the form of detoxification are widespread and some prokaryotes can even use arsenic as an energy source. We first screened the genomes of 76 Thioalkalivibrio strains for the presence of known arsenic oxidoreductases and found 15 putative ArxA (arsenite oxidase) and two putative ArrA (arsenate reductase). Subsequently, we studied the resistance to arsenite in detail in Thioalkalivibrio jannaschii ALM2(T), and Thioalkalivibrio thiocyanoxidans ARh2(T) by comparative genomics and by growing them at different arsenite concentrations followed by arsenic species and transcriptomic analysis. Tv. jannaschii ALM2(T), which has been isolated from Mono Lake, an arsenic-rich soda lake, could resist up to 5 mM arsenite, whereas Tv. thiocyanoxidans ARh2(T), which was isolated from a Kenyan soda lake, could only grow up to 0.1 mM arsenite. Interestingly, both species oxidized arsenite to arsenate under aerobic conditions, although Tv. thiocyanoxidans ARh2(T) does not contain any known arsenite oxidases, and in Tv. jannaschii ALM2(T), only arxB2 was clearly upregulated. However, we found the expression of a SoeABC-like gene, which we assume might have been involved in arsenite oxidation. Other arsenite stress responses for both strains were the upregulation of the vitamin B-12 synthesis pathway, which can be linked to antioxidant activity, and the up- and downregulation of different DsrE/F-like genes whose roles are still unclear. Moreover, Tv. jannaschii ALM2(T) induced the ars gene operon and the Pst system, and Tv. thiocanoxidans ARh2(T) upregulated the sox and apr genes as well as different heat shock proteins. Our findings for Thioalkalivibrio confirm previously observed adaptations to arsenic, but also provide new insights into the arsenic stress response and the connection between the arsenic and the sulfur cycle
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