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You searched for subject:(Chlorobium tepidum). Showing records 1 – 3 of 3 total matches.

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Penn State University

1. Gomez Maqueo Chew, Aline. Elucidation of the bacteriochlorophyll c biosynthesis pathway in green sulfur bacterium Chlorobium tepidum.

Degree: 2008, Penn State University

Green sulfur bacteria (GSB) are a unique group of strictly anaerobic organisms. Theyhave been isolated from microbial mats, from below the chemocline of stratified lakes, from sediments and even from the surroundings of deep-sea hydrothermal vents. Theanaerobic environments in which GSB usually thrive are normally very light-limited. GSB have developed a large light-harvesting antenna, the chlorosome, in order to survivein such environments. Chlorosomes are unlike any other known light-harvesting antenna, because they do not require a protein scaffold for assembly. Structures formed from theself-aggregation of BChls c, d or e form the bulk of the chlorosome. The antenna BChls share unique characteristics that allow the formation of the chlorosome aggregates.These BChls have a hydroxyl moiety at the C-3(1) position that chelates the Mg of a neighboring molecule, which allows the formation of the higher order aggregates of thechlorosome. These chlorophylls also lack the C-13(2) methyl-carboxyl moiety found in other (B)Chls, which would otherwise interfere with aggregate formation. GSB alsomethylate these antenna BChls at the C-20, C-8(2) and C-12(1) positions. In addition to the antenna BChls, GSB produce Chl a and BChl a. Although the pathways for thebiosynthesis of Chl a and BChl a have been elucidated in plants and algae and purple bacteria, respectively, very little was known about the biosynthesis of the chlorosomeantenna BChls. By using the wealth of data available from the sequencing and annotation of the genome of the GSB Chlorobium tepidum, genes possibly involved in (B)Chlbiosynthesis were identified and targeted for inactivation. Mutants of C. tepidum, affected in (B)Chl biosynthesis were constructed and characterized. The characterization of themutants enabled the identification of previously unknown enzymes responsible for the C8 vinyl reduction (BciA), and C-8(2) (BchQ) and C-12(1) (BchR) methylations. Severalorange mutants of C. tepidum, impaired in their ability to synthesize wild-type levels of BChl c, were also characterized. These mutants were impaired at different points in theBChl c biosynthetic pathway. A mutant of bchS, a paralog of the gene encoding the large Mg-chelatase subunit BchH, produced only 10% the BChl c of the wild type and excretedlarge amounts of protoporphyrin-IX into the growth medium. A strain carrying amutation in bchJ, a gene that had been incorrectly assumed to encode the C-8 vinyl reductase, produced 9% the wild-type levels of BChl c and excreted large amounts ofdivinyl-protochlorophyllide into the media. Finally, a bchU bchQ bchR triple mutant of C. tepidum, which is unable to methylate the BChl c molecule, produced less than 30% ofthe BChl c of the wild type. Based on these results, a pathway for the biosynthesis of (B)Chls in C. tepidum was proposed. The accumulation of divinyl-protochlorophyllide inthe bchJ mutant, helped place the branching of the three (B)Chl biosynthetic pathways of C. tepidum at the level of Chlide a. The only step remaining to be identified in BChl… Advisors/Committee Members: Donald Ashley Bryant, Committee Chair/Co-Chair, John H Golbeck, Committee Chair/Co-Chair, Joseph M Bollinger Jr., Committee Member, B Tracy Nixon, Committee Member, Carsten Krebs, Committee Member, Timothy W Mcnellis, Committee Member.

Subjects/Keywords: chlorophyll biosynthesis; bacteriochlorophyll c; photosynthesis; Chlorobium tepidum; green sulfur bacteria

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APA (6th Edition):

Gomez Maqueo Chew, A. (2008). Elucidation of the bacteriochlorophyll c biosynthesis pathway in green sulfur bacterium Chlorobium tepidum. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/7511

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Gomez Maqueo Chew, Aline. “Elucidation of the bacteriochlorophyll c biosynthesis pathway in green sulfur bacterium Chlorobium tepidum.” 2008. Thesis, Penn State University. Accessed September 19, 2020. https://submit-etda.libraries.psu.edu/catalog/7511.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Gomez Maqueo Chew, Aline. “Elucidation of the bacteriochlorophyll c biosynthesis pathway in green sulfur bacterium Chlorobium tepidum.” 2008. Web. 19 Sep 2020.

Vancouver:

Gomez Maqueo Chew A. Elucidation of the bacteriochlorophyll c biosynthesis pathway in green sulfur bacterium Chlorobium tepidum. [Internet] [Thesis]. Penn State University; 2008. [cited 2020 Sep 19]. Available from: https://submit-etda.libraries.psu.edu/catalog/7511.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Gomez Maqueo Chew A. Elucidation of the bacteriochlorophyll c biosynthesis pathway in green sulfur bacterium Chlorobium tepidum. [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/7511

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


University of Oslo

2. Anonsen, Jan Haug. Investigation of the genes coding for chaperonins in Chlorobium tepidum.

Degree: 2005, University of Oslo

A subgroup of the universally conserved molecular chaperones, the chaperonins assist other proteins in folding or refolding in an ATP- dependent manner. First discovered in E. coli the best described member is the GroEL (Hsp60) and GroES (Hsp10), which are often found together in an operon. The genes for these chaperonins are commonly regulated positive by an alternative sigma factor, as in E. coli or negatively by the CIRCE/ HrcA feedback regulatory system as in streptomyces. C. tepidum, a green sulphur bacterium, contains an operon consisting of groEL and groES, and a single groES-2 gene. In this work extensive analysis of the genetic sequences, in particular the regulatory upstream region was done. This information was used for structure modelling as well as to design primers for isolation and detection of genes by PCR. The isolated genes were subsequently ligated into a pET 102/ D TOPO® vector and expressed in transformed E. coli BL21 (DE) cells. All genes were expressed with a thioredoxin fusion protein in this work. To detect expression of groES, groEL and groES-2 genes in C. tepidum a Real Time reverse transcriptase PCR were done on RNA extracted from C. tepidum. However, this experiment encountered obstacles and were not finished due to lack of time. Advisors/Committee Members: Reidun Sirevåg.

Subjects/Keywords: molekylærbiologi chaperoniner chlorobium tepidum regulering groESL transformasjon ekspresjon; VDP::473

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APA (6th Edition):

Anonsen, J. H. (2005). Investigation of the genes coding for chaperonins in Chlorobium tepidum. (Thesis). University of Oslo. Retrieved from http://urn.nb.no/URN:NBN:no-11383 ; https://www.duo.uio.no/handle/10852/11487

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Anonsen, Jan Haug. “Investigation of the genes coding for chaperonins in Chlorobium tepidum.” 2005. Thesis, University of Oslo. Accessed September 19, 2020. http://urn.nb.no/URN:NBN:no-11383 ; https://www.duo.uio.no/handle/10852/11487.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Anonsen, Jan Haug. “Investigation of the genes coding for chaperonins in Chlorobium tepidum.” 2005. Web. 19 Sep 2020.

Vancouver:

Anonsen JH. Investigation of the genes coding for chaperonins in Chlorobium tepidum. [Internet] [Thesis]. University of Oslo; 2005. [cited 2020 Sep 19]. Available from: http://urn.nb.no/URN:NBN:no-11383 ; https://www.duo.uio.no/handle/10852/11487.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Anonsen JH. Investigation of the genes coding for chaperonins in Chlorobium tepidum. [Thesis]. University of Oslo; 2005. Available from: http://urn.nb.no/URN:NBN:no-11383 ; https://www.duo.uio.no/handle/10852/11487

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

3. Roy, E. Biological diversity of photosynthetic reaction centers and the solid-state photo-CIDNP effect.

Degree: 2007, Solid state NMR group/ Leiden Institute of Chemistry (LIC), Faculty of Science, Leiden University

Photosynthetic reaction centers (RCs) from plants, heliobacteria and green sulphur bacteria has been investigated with photochemically induced dynamic nuclear polarization (photo-CIDNP) MAS NMR. In photosystem (PS) I of spinach, all signals appear negative which is proposed by a predominance of the three spin mixing (TSM) over the differential decay (DD) mechanism. There are contrasting magnetic-field dependence of photo-CIDNP of PSI and PSII. For PSII the optimal NMR enhancement factor of ~5000 is observed at 4.7 T, while the strongest light-induced signals of PSI are at 9.4 T. The simulations indicate that difference between bacterial RCs and plant PS I can be due to an increase of the exchange coupling between the donor and acceptor radicals. In the RCs of Chlorobium tepidum the spectra appear negative and can be tentatively assigned to two bacterio chlorophyll a molecules of the donor. The spectral pattern obtained from membrane fragments of Heliobacillus mobilis at 4.7 T, appear to be both positive and negative, which is similar to the pattern observed in the RCs of plant PSII and RCs of Rhodobacter sphaeroides R-26. However, unlike the other RCs, in this system, at 17.6 T, the positive signals undergo a sign change and appear negative. Advisors/Committee Members: Supervisor: Groot H.J.M. de Co-Supervisor: Matysik J..

Subjects/Keywords: Chlorobium tepidum; Heliobacillus mobilis; Photo-CIDNP; Photosynthetic reaction centers; Photosystem I; Solid-state NMR; Chlorobium tepidum; Heliobacillus mobilis; Photo-CIDNP; Photosynthetic reaction centers; Photosystem I; Solid-state NMR

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Roy, E. (2007). Biological diversity of photosynthetic reaction centers and the solid-state photo-CIDNP effect. (Doctoral Dissertation). Solid state NMR group/ Leiden Institute of Chemistry (LIC), Faculty of Science, Leiden University. Retrieved from http://hdl.handle.net/1887/12373

Chicago Manual of Style (16th Edition):

Roy, E. “Biological diversity of photosynthetic reaction centers and the solid-state photo-CIDNP effect.” 2007. Doctoral Dissertation, Solid state NMR group/ Leiden Institute of Chemistry (LIC), Faculty of Science, Leiden University. Accessed September 19, 2020. http://hdl.handle.net/1887/12373.

MLA Handbook (7th Edition):

Roy, E. “Biological diversity of photosynthetic reaction centers and the solid-state photo-CIDNP effect.” 2007. Web. 19 Sep 2020.

Vancouver:

Roy E. Biological diversity of photosynthetic reaction centers and the solid-state photo-CIDNP effect. [Internet] [Doctoral dissertation]. Solid state NMR group/ Leiden Institute of Chemistry (LIC), Faculty of Science, Leiden University; 2007. [cited 2020 Sep 19]. Available from: http://hdl.handle.net/1887/12373.

Council of Science Editors:

Roy E. Biological diversity of photosynthetic reaction centers and the solid-state photo-CIDNP effect. [Doctoral Dissertation]. Solid state NMR group/ Leiden Institute of Chemistry (LIC), Faculty of Science, Leiden University; 2007. Available from: http://hdl.handle.net/1887/12373

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