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Showing 1 to 20 of 34 for “"cobalamin"”.
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Cobalamin-Enhanced Anaerobic Biotransformation of Carbon Tetrachloride
… demonstrated that adding catalytic amounts of cobalamins improves biotransformation of high concentrations of CT by increasing the rate and minimizing the accumulation of hazardous products. Relatively low adsorption of CN-Cbl in sand indicated that adding cobalamins to groundwater for in situ …
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Cobalamin-Enhanced Anaerobic Biotransformation of Carbon Tetrachloride
… CT concentrations by supplementing cultures with cobalamins. Three different cultures; an acetogenic pure culture-Acetobacterium woodii (ATCC-29683), a dichloromethane degrading enrichment culture, and a methanol enrichment culture were studied for this purpose.
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The Mechanism of Cobalamin-Dependent Methyl Transfer
Made available in DSpace on 2014-12-10T23:24:27Z (GMT). No. of bitstreams: 1 7207029.pdf: 5004514 bytes, checksum: 42e1c38cc711b5caca9e9b9ca2ced4e2 (MD5) Previous issue date: 1971
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Cobalamin Binding to Proteins of Physiological Significance
Made available in DSpace on 2014-12-10T23:24:29Z (GMT). No. of bitstreams: 1 7317299.pdf: 3994028 bytes, checksum: a559365c554602d18bff05f85232a78a (MD5) Previous issue date: 1972
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Characterizing cobalamin cycling by Antarctic marine microbes across multiple scales
… is primarily limited by iron and co-limited by cobalamin (vitamin B12), a trace cobalt-containing organometallic compound only synthesized by some bacteria and archaea. These micronutrients impact primary production and the microbial ecology of the two keystone phytoplankton types: diatoms and …
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Characterizing cobalamin cycling by Antarctic marine microbes across multiple scales
… is primarily limited by iron and co-limited by cobalamin (vitamin B₁₂), a trace cobalt-containing organometallic compound only synthesized by some bacteria and archaea. These micronutrients impact primary production and the microbial ecology of the two keystone phytoplankton types: diatoms and …
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The Relationship between Cobalamin Deficiency and Neurological Dysfunction in Older Adults
<p>The prevalence of cobalamin (Obi) deficiency among older adults is higher than among younger adults, and is estimated to be between 14% and 23%. Persistent Cbl deficiency can cause a variety of neurological deficits. Neurological dysfunction occurs commonly among older adults, raising the …
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Whole-genome transposon mutagenesis to elucidate the genetic requirements for vitamin B12 biosynthesis and assimilation in mycobacteria
… analyses have identified an altered capacity for cobalamin biosynthesis as a critical step in the evolution of the pathogenic Mycobacterium tuberculosis Complex strains from a common environmental ancestor. However, resolving the full gene complement involved in the complex, multi-step pathway for …
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Light-sensing in bacteria
… protein, despite its sequence similarity to cobalamin-binding proteins. My research showed that PpaA is in fact a bona fide cobalamin-binding protein. PpaA binds specifically hydroxy-cobalamin, but not other forms of cobalamin. PpaA does have some ability to bind heme, but a mutant form of …
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Molecular biology of B vitamin metabolism genes and their regulation in Phaeodactylum tricornutum
… been previously observed to be downregulated by cobalamin (vitamin B12) supplementation in diatoms reflecting the interconnectedness and co-regulation of different B vitamin metabolisms. The aim of this thesis is to investigate different aspects of the regulation of thiamine and cobalamin-related …
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Investigating the provision of vitamin B₁₂ in the Micro-Ecological Life Support System Alternative (MELiSSA) loop for long-distance space exploration using algal-bacterial cocultures.
Vitamin B₁₂ (cobalamin) is an essential nutrient for humans as it is required as a cofactor for two enzymes involved in central metabolism, methionine synthase and methylmalonyl CoA mutase. It is a corrinoid molecule, composed of a modified tetrapyrrole ring- with a cobalt ion at the centre and …
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Metal complexes of non-heme ligands: biological applications
… like that of biologically important cofactor cobalamin or B<sub>12</sub> (Cbl) are reported. Different non–heme ligand sets or inhibitors were used to inactivate different proteins. Carbonic anhydrase–I (CA–I) and 20S proteasome were inactivated by iron complexes in the presence of …
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Community Composition and Function of the Hindgut Microbiome in Seaweed-Eating Marine Fish
… capabilities such as nitrogen fixation and cobalamin biosynthesis. The Alistipes from K. sydneyanus encoded a distinct CAZyme composition for marine polysaccharides, suggesting adaptation of their CAZyme repertoire to the host diet. Analysis of transcriptional activity within the K. …
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Riboswitch regulation of methionine metabolism and vitamin B12 uptake in mycobacteria – implications for drug susceptibility and pathogenesis
… of metE, the gene encoding the mycobacterial cobalamin-independent methionine synthase. Owing to this repression, metH, a gene encoding the cobalamin-dependent methionine synthase, was found to be conditionally essential for bacillary replication in vitro. Drug susceptibility testing to …
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Investigation on the Mechanism of Formation and Consumption of Vinylcobalamins Involved in Vitamin B(12)-Catalyzed Reductive Dechlorination of Perchloroethylene
Similar experiments were undertaken using cobalamins to further investigate the vitamin B12-catalyzed dechlorination of PCE. Chlorovinylcobalamin 16, previously detected in the PCE dechlorination reaction, was synthesized by treating cob(I)alamin with chloroacetylene. The structure of 16 was …
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Development of a novel cyanide-free method for analysis of vitamin B₁₂ in milk-based infant formula
… to convert the three unstable vitamers (hydroxocobalamin, methylcobalamin and adenosylcobalamin) to cyanocobalamin, the most stable form of vitamin B₁₂. The undesirable handling of cyanide for the analyst in the laboratory and the associated safety risk indicates a clear necessity for …
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Zielgerichtete Mutagenese bei Zink-Thiolat-Modell-Komplexen für Alkyltransferasen-Reaktivitätskontrolle gegenüber Alkylierungsmitteln
… von Homocystein an das aktive Zentrum der Cobalamin-unabhängigen Methionin-Synthetase und dessen Alkylierung zu Methionin. Ziel dieser Arbeit war es, zu klären, weshalb in diesem Enzym die Zink-NS3-Umgebung vorliegt. Deshalb sollte bei einkernigen Zink-Thiolat-Komplexen mit …
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Crystallization studies of 5'-deoxyadenosyl radical enzymes
Both adenosylcobalamin- and S-adenosylmethionine-dependent radical enzymes use a 5'-deoxyadenosyl radical intermediate to abstract a hydrogen atom from their substrates. In the case of adenosylcobalamin-dependent enzymes, the 5'-deoxyadenosyl radical is generated by homolytic cleavage of the …
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Serum Vitamin B-12 Levels and Urinary Methylmalonate Excretion in Total Vegetarians
… total vegetarians who did not actively take a cobalamin supplement had below normal serum vitamin B-12 levels. Of this group that had low serum vitamin B-12 levels 83% also had an elevated UMMA indicating a possible biochemical limitation in the body due to a lack of adequate vitamin B-12. It …
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Investigating the molecular basis of vitamin B12 uptake in Chlamydomonas reinhardtii
… dependent on an external supply of the corrinoid cobalamin (vitamin B12) for growth. Algal phyla differ in the proportion of species dependent on B12. Extremes of this are the Chlorophyta (30% B12 dependent) and the Dinophyta (91% B12 dependent). B12 is only synthesised by prokaryotic organisms, …
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