Search results for "synthesis"
showing 10 items of 2844 documents
Oxygen Availability, Energy Metabolism, and Metabolic Rate in Invertebrates and Vertebrates
1988
It has often been emphasized that primitive life originated in an environment devoid of oxygen. The first eukaryotic cells, however, appeared some 1.4 billion years ago when the earth’s atmosphere had already turned from a mildly reducing to an oxidizing one by the photosynthetic action of prokaryotes that used H20 as reducing agent (see Harold 1986, for review). The presence of free oxygen obviously was a major force shaping the evolution of eukaryotic cells. As a consequence all animals are primarily aerobes, using respiratory chains with oxygen as electron acceptor (oxidant) and membrane-bound ATP synthases for the production of ATP.
A Versatile Grafting-to Approach for the Bioconjugation of Polymers to Collagen-like Peptides Using an Activated Ester Chain Transfer Agent
2009
DepartmentofMaterials Science and Engineering, University of Delaware, 201DuPont Hall, Newark, Delaware 19716,Received February 24, 2009Revised Manuscript Received April 24, 2009Biohybrid materials consisting of synthetic polymers andbiological moieties have gained more and more interest in therecent years.
l-Valine biosynthesis during batch and fed-batch cultivations of Corynebacterium glutamicum: Relationship between changes in bacterial growth rate an…
2007
Abstract A transition in the bacterial growth rate to below maximum was found to be an optimum parameter of cellular physiology to increase the activity of acetohydroxy acid synthase, a regulatory enzyme in l -valine synthesis, and amino acid overproduction by Corynebacterium glutamicum ATCC 13032 recombinants under batch and fed-batch cultivation conditions. An increase in l -valine synthesis under transient situations when cellular growth rate was downregulated was correlated to a decrease in the activity of aconitase, a key enzyme in the tricarboxylic acid cycle (TCA) of C. glutamicum , and, in contrast, to an increase in the activity of glucose-6-phosphate dehydrogenase, a key enzyme in…
Carbamate Linker Strategy in Solid-Phase Synthesis of Amino-Functionalized Glycoconjugates for Attachment to Solid Surfaces and Investigation of Prot…
2009
Amino-functionalized serine-based galactose and glucose neoglycolipids were prepared by solid-phase synthesis using a carbamate strategy for anchoring amino functionalities to a (2-fluoro-4-hydroxy ...
Synthesis and Photoluminescent Properties of 1,1‘-Binaphthyl-Based Chiral Phenylenevinylene Dendrimers
2003
New chiral, soluble binaphthyl derivatives that incorporate stilbenoid dendrons at the 6,6â²-positions have been prepared. The synthesis of the new enantiopure dendrimers was performed in a convergent manner by Horner-Wadsworth-Emmons (HWE) reaction of the appropriately functionalized 1,1â²-binaphthyl derivative (R)-1 and the appropriate dendrons (R)2nGn-CHO. Different electroactive units were incorporated in the peripheral positions of the dendrons in order to tune both the optical and electrochemical behavior of these systems. Fluorescence measurements on the chiral dendrimers reveal a strong emission with maxima between 409 and 508 nm depending upon the substitution pattern. Finally, t…
Patterns of wall synthesis inSaccharomyces cerevisiae
1979
Wall formation inSaccharomyces cerevisiae seems to be the result of two main patterns of wall material deposition: (i) around the whole periphery of the cell in nonbudding ones, and (ii) mainly at the tip of the daughter cell or at the cross wall that separates dividing cells. This interpretation has been obtained following experiments in which RNA or protein synthesis has been inhibited. Under these conditions, glucan formation takes place, and wall thickening is probably due to the accumulation of this polysaccharide. Furthermore, once a pattern of wall deposition has been established, it is not modified by inhibition of RNA or protein synthesis.
Regulation of chitin synthase activity inSaccharomyces cerevisiae: Effect of the inhibition of cell division and of synthesis of RNA and protein
1980
The effect of pronase and trypsin on the activation or deactivation (degradation?) of chitin synthase ofSaccharomyces cerevisiae occurs faster in membranous preparations than in toluene-treated cells. When the temperature is raised, the former preparation is deactivated earlier than the latter one. The activity found in growing cells is not modified after inhibition of protein synthesis by cycloheximide or amino acid starvation or by the inhibition of RNA synthesis. It was possible to activate the chitin synthase ofS. cerevisiae cdc 25 grown at 23°C by means of pronase, whereas trypsin had no effect. After the cells were grown at 37°C, chitin synthase could not be activated either with tryp…
SF002-96-1, a new drimane sesquiterpene lactone from an Aspergillus species, inhibits survivin expression
2013
Survivin, a member of the IAP (inhibitor of apoptosis) gene family, is overexpressed in virtually all human cancers and is functionally involved in the inhibition of apoptosis, regulation of cell proliferation, metastasis and resistance to therapy. Because of its upregulation in malignancy, survivin has currently attracting considerable interest as a new target for anticancer therapy. In a screening of approximately 200 strains of imperfect fungi for the production of inhibitors of survivin promoter activity, a new drimane sesquiterpene lactone, SF002-96-1, was isolated from fermentations of an Aspergillus species. The compound inhibited survivin promoter activity in transiently transfected…
Outstandingly robust anodic dehydrogenative aniline coupling reaction
2020
Abstract Oxidative treatment of anilines usually leads to the formation of black polymers, often referred to as “aniline black”. This over-oxidation is hardly controllable and also a challenging task in the anodic conversion of anilines. Here, a quick and efficient access to valuable building blocks by anodic cross- and homo-coupling of aniline and benzidine derivatives is reported. This electrosynthesis is easily performed in a simple undivided cell using constant current conditions. The key to the observed outstanding performance and robustness of this system is attributed to the used solvent 1,1,1,3,3,3-hexafluoroisopropanol. The extraordinary performance over a broad range of current de…
Stereoselective Synthesis and Structural Correction of the Naturally Occurring Lactone Stagonolide G
2010
A convergent synthesis of the structure proposed for the naturally occurring lactone stagonolide G is described. All three stereocenters were created with the aid of asymmetric Brown allylations. The lactone ring was built by means of a ring-closing metathesis (RCM). The synthetic and the natural compound differed in their spectral properties. A new structure is now proposed for stagonolide G and demonstrated by means of a chemical transformation.