scholarly journals Initial Characterization of the Photosynthetic Apparatus of “Candidatus Chlorothrix halophila,” a Filamentous, Anoxygenic Photoautotroph

2007 ◽  
Vol 189 (11) ◽  
pp. 4196-4203 ◽  
Author(s):  
Allison M. L. van de Meene ◽  
Tien Le Olson ◽  
Aaron M. Collins ◽  
Robert E. Blankenship
Keyword(s):  
Photosynthetic Bacteria ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Photosynthetic Apparatus ◽  
Fluorescence Emission ◽  
Photosynthetic Characteristics ◽  
Green Bacteria ◽  
Green Photosynthetic Bacteria ◽  
Antenna Complex ◽  
Membrane Bound

ABSTRACT “Candidatus Chlorothrix halophila” is a recently described halophilic, filamentous, anoxygenic photoautotroph (J. A. Klappenbach and B. K. Pierson, Arch. Microbiol. 181:17-25, 2004) that was enriched from the hypersaline microbial mats at Guerrero Negro, Mexico. Analysis of the photosynthetic apparatus by negative staining, spectroscopy, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that the photosynthetic apparatus in this organism has similarities to the photosynthetic apparatus in both the Chloroflexi and Chlorobi phyla of green photosynthetic bacteria. The chlorosomes were found to be ellipsoidal and of various sizes, characteristics that are comparable to characteristics of chlorosomes in other species of green photosynthetic bacteria. The absorption spectrum of whole cells was dominated by the chlorosome bacteriochlorophyll c (BChl c) peak at 759 nm, with fluorescence emission at 760 nm. A second fluorescence emission band was observed at 870 nm and was tentatively attributed to a membrane-bound antenna complex. Fluorescence emission spectra obtained at 77 K revealed another complex that fluoresced at 820 nm, which probably resulted from the chlorosome baseplate complex. All of these results suggest that BChl c is present in the chlorosomes of “Ca. Chlorothrix halophila,” that BChl a is present in the baseplate, and that there is a membrane-bound antenna complex. Analysis of the proteins in the chlorosomes revealed an ∼6-kDa band, which was found to be related to the BChl c binding protein CsmA found in other green bacteria. Overall, the absorbance and fluorescence spectra of “Ca. Chlorothrix halophila” revealed an interesting mixture of photosynthetic characteristics that seemed to have properties similar to properties of both phyla of green bacteria when they were compared to the photosynthetic characteristics of Chlorobium tepidum and Chloroflexus aurantiacus.

scholarly journals CsmA Protein is Associated with BChl a in the Baseplate Subantenna of Chlorosomes of the Photosynthetic Green Filamentous Bacterium Oscillochloris trichoides belonging to the Family Oscillochloridaceae

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Anastasiya Zobova ◽  
Alexandra Taisova ◽  
Eugeny Lukashev ◽  
Nataliya Fedorova ◽  
Ludmila Baratova ◽  
...  
Keyword(s):  
Gel Electrophoresis ◽  
Photosynthetic Bacteria ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Green Photosynthetic Bacteria ◽  
The Third ◽  
The Family ◽  
Anoxygenic Photosynthetic Bacteria ◽  
Green Bacterium ◽  
Universal Interface

The baseplate subantenna in chlorosomes of green anoxygenic photosynthetic bacteria, belonging to the families Chloroflexaceae and Chlorobiaceae, is known to represent a complex of bacteriochlorophyll (BChl) a with the ~6 kDa CsmA proteins. Earlier, we showed the existence of a similar BChl a subantenna in chlorosomes of the photosynthetic green bacterium Oscillochloris trichoides, member of Oscillochloridaceae, the third family of green photosynthetic bacteria. However, this BChl a subantenna was not visually identified in absorption spectra of isolated Osc. trichoides chlorosomes in contrast to those of Chloroflexaceae and Chlorobiaceae. In this work, using room and low-temperature absorbance and fluorescence spectroscopy and sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis of alkaline-treated and untreated chlorosomes of Osc. trichoides, we showed that the baseplate BChl a subantenna does exist in Oscillochloridaceae chlorosomes as a complex of BChl a with the 5.7 kDa CsmA protein. The present results support the idea that the baseplate subantenna, representing a complex of BChl a with a ~6 kDa CsmA protein, is a universal interface between the BChl c subantenna of chlorosomes and the nearest light-harvesting BChl a subantenna in all three known families of green anoxygenic photosynthetic bacteria.

scholarly journals Do photosynthetic bacteria contain cytochrome c1?

1980 ◽  
Vol 189 (3) ◽  
pp. 385-391 ◽  
Author(s):  
P M Wood
Keyword(s):  
Photosynthetic Bacteria ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Photosynthetic Electron Transport ◽  
Photosynthetic Bacterium ◽  
Alpha Band ◽  
Midpoint Potential ◽  
Cytochrome C2 ◽  
Cytochrome C1 ◽  
Membrane Bound

A method is described for characterizing, c-type cytochromes in bacterial membrane preparations according to molecular weight on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Applied to the photosynthetic bacterium Rhodopseudomonas sphaeroides this technique is used, together with spectroscopic measurements, to demonstrate that a membrane-bound cytochrome c of mol.wt. 30000 is active in photosynthetic electron transport in addition to the well-known soluble cytochrome, cytochrome c2. The membrane cytochrome has a midpoint potential (E'0) at pH 7 of +290 mV, as compared with +360 mV for purified cytochrome c2. Its alpha-band has a peak near 552 nm, as compared with 550 nm for cytochrome c2. Evidence is presented that chromatophores contain roughly equal amounts of the two cytochromes.

scholarly journals Time-dependent association between platelet-bound fibrinogen and the Triton X-100 insoluble cytoskeleton

Blood ◽  
1991 ◽  
Vol 77 (3) ◽  
pp. 508-514 ◽  
Author(s):  
EI Peerschke
Keyword(s):  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Adenosine Diphosphate ◽  
Time Dependent ◽  
Binding Studies ◽  
Fibrinogen Binding ◽  
Human Thrombin ◽  
Membrane Bound ◽  
Independent Association ◽  
Triton X

Abstract Previous studies indicated a correlation between the formation of EDTA- resistant (irreversible) platelet-fibrinogen interactions and platelet cytoskeleton formation. The present study explored the direct association of membrane-bound fibrinogen with the Triton X-100 (Sigma Chemical Co, St Louis, MO) insoluble cytoskeleton of aspirin-treated, gel-filtered platelets, activated but not aggregated with 20 mumol/L adenosine diphosphate (ADP) or 150 mU/mL human thrombin (THR) when bound fibrinogen had become resistant to dissociation by EDTA. Conversion of exogenous 125I-fibrinogen to fibrin was prevented by adding Gly-Pro-Arg and neutralizing THR with hirudin before initiating binding studies. After 60 minutes at 22 degrees C, the cytoskeleton of ADP-treated platelets contained 20% +/- 12% (mean +/- SD, n = 14) of membrane-bound 125I-fibrinogen, representing 10% to 50% of EDTA- resistant fibrinogen binding. The THR-activated cytoskeleton contained 45% +/- 15% of platelet bound fibrinogen, comprising 80% to 100% of EDTA-resistant fibrinogen binding. 125I-fibrinogen was not recovered with platelet cytoskeletons if binding was inhibited by the RGDS peptide, excess unlabeled fibrinogen, or disruption of the glycoprotein (GP) IIb-IIIa complex by EDTA-treatment. Both development of EDTA- resistant fibrinogen binding and fibrinogen association with the cytoskeleton were time dependent and reached maxima 45 to 60 minutes after fibrinogen binding to stimulated platelets. Although a larger cytoskeleton formed after platelet stimulation with thrombin as compared with ADP, no change in cytoskeleton composition was noted with development of EDTA-resistant fibrinogen binding. Examination of platelet cytoskeletons using monoclonal antibodies, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and Western blotting showed the presence of only traces of GP IIb-IIIa in the cytoskeletons of resting platelets, with no detectable increases after platelet activation or development of EDTA-resistant fibrinogen binding. These data suggest that GP IIb-IIIa-mediated fibrinogen binding to activated platelets is accompanied by time-dependent alterations in platelet- fibrinogen interactions leading to the GP IIb-IIIa independent association between bound fibrinogen and the platelet cytoskeleton.

scholarly journals Soluble stem cell factor in human serum

Blood ◽  
1993 ◽  
Vol 81 (3) ◽  
pp. 656-660 ◽  
Author(s):  
KE Langley ◽  
LG Bennett ◽  
J Wypych ◽  
SA Yancik ◽  
XD Liu ◽  
...  
Keyword(s):  
Stem Cell ◽  
Human Serum ◽  
Stem Cell Factor ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Immunoaffinity Chromatography ◽  
Soluble Form ◽  
Enzyme Linked Immunosorbent Assay ◽  
Functional Importance ◽  
Membrane Bound

Stem cell factor (SCF) is a recently described factor active in the early stages of hematopoiesis. It can exist in membrane-bound form and in proteolytically released soluble form. The levels and nature of SCF in human serum are described. As determined by an enzyme-linked immunosorbent assay performed for 257 samples, SCF level in serum averaged 3.3 +/- 1.1 ng/mL. The serum SCF was partially purified by immunoaffinity chromatography and analyzed by glycosidase treatments in conjunction with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. The results show that the SCF has N- linked and O-linked carbohydrate and corresponds to the soluble form, at or about 165 amino acids in length. The findings suggest functional importance for soluble SCF in humans.

scholarly journals Role of membrane-bound and free polyribosomes in the synthesis of cytochrome c in rat liver

1974 ◽  
Vol 140 (2) ◽  
pp. 157-167 ◽  
Author(s):  
Néstor F. González-Cadavid ◽  
Carmen Sáez De Córdova
Keyword(s):  
Endoplasmic Reticulum ◽  
Cytochrome C ◽  
Rat Liver ◽  
Cell Structure ◽  
Polyacrylamide Gel Electrophoresis ◽  
Mitochondrial Protein ◽  
Sodium Dodecyl ◽  
Membrane Bound

The functional distinction of membrane-bound and free polyribosomes for the synthesis of exportable and non-exportable proteins respectively is not so strict as was initially thought, and it was therefore decided to investigate their relative contribution to the elaboration of an internal protein integrated into a cell structure. Cytochrome c was chosen as an example of a soluble mitochondrial protein, and the incorporation of [14C]leucine and δ-amino[14C]laevulinate into the molecule was studied by using different ribosomal preparations from regenerating rat liver. A new procedure was devised for the purification of cytochrome c, based on ion-exchange chromatography combined with sodium dodecyl sulphate–polyacrylamide-gel electrophoresis. In spite of cytochrome c being a non-exportable protein, the membrane-bound polyribosomes were at least as active as the free ribosomes in the synthesis in vitro of the apoprotein and the haem moiety. The detergent-treated ribosomes could also effect the synthesis of cytochrome c, although at a lower rate. Since in liver more than two-thirds of the ribosomes are bound to the endoplasmic-reticulum membranes, it is considered that in vivo they are responsible for the synthesis of most of the cytochrome c content of the cell. This suggests that in secretory tissues the endoplasmic reticulum plays a predominant role in mitochondrial biogenesis, although free ribosomes may participate in the partial turnover of some parts of the organelle. The hypothesis on the functional specialization of the different kinds of ribosomes was therefore modified to account for their parallel intervention in the synthesis of proteins associated with membranous structures.

scholarly journals Soluble stem cell factor in human serum

Blood ◽  
1993 ◽  
Vol 81 (3) ◽  
pp. 656-660 ◽  
Author(s):  
KE Langley ◽  
LG Bennett ◽  
J Wypych ◽  
SA Yancik ◽  
XD Liu ◽  
...  
Keyword(s):  
Stem Cell ◽  
Human Serum ◽  
Stem Cell Factor ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Immunoaffinity Chromatography ◽  
Soluble Form ◽  
Enzyme Linked Immunosorbent Assay ◽  
Functional Importance ◽  
Membrane Bound

Abstract Stem cell factor (SCF) is a recently described factor active in the early stages of hematopoiesis. It can exist in membrane-bound form and in proteolytically released soluble form. The levels and nature of SCF in human serum are described. As determined by an enzyme-linked immunosorbent assay performed for 257 samples, SCF level in serum averaged 3.3 +/- 1.1 ng/mL. The serum SCF was partially purified by immunoaffinity chromatography and analyzed by glycosidase treatments in conjunction with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. The results show that the SCF has N- linked and O-linked carbohydrate and corresponds to the soluble form, at or about 165 amino acids in length. The findings suggest functional importance for soluble SCF in humans.

scholarly journals Preliminary characterization of two thymus-dependent xenoantigens from mouse lymphocytes

1977 ◽  
Vol 163 (2) ◽  
pp. 211-217 ◽  
Author(s):  
I S Trowbridge ◽  
M Nilsen-Hamilton ◽  
R T Hamilton ◽  
M J Bevan
Keyword(s):  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Membrane Vesicles ◽  
Sodium Deoxycholate ◽  
Pea Lectin ◽  
Preliminary Characterization ◽  
Low Concentrations ◽  
Membrane Bound

Preliminary characterization of two mouse thymus-dependent (T) lymphocyte xenoantigens, T25 and T200, which are selectively labelled by lactoperoxidase-catalysed iodination of T-cells, is described. Both molecules are membrane-bound glycoproteins. Fractionation of membrane vesicles prepared from BW5147 lymphoma cells by sedimentation through sucrose density gradients show that antigens T25 and T200 are in fractions enriched with plasma membrane. Moreover antigen T200 is partially degraded when viable cells are treated briefly with low concentrations of trypsin. Both molecules are efficiently solubilized in buffers containing sodium deoxycholate or Nonidet P-40, as measured by failure to sediment at 100000g for 60min. However, gel filtration on Sepharose 6B showed the presence of aggregated material in Nonidet P-40 extracts which was not found in deoxycholate-solubilized membranes. After solubilization in detergent, antigens T25 and T200 bind to, and may be specifically eluted from, columns of pea lectin--Sepharose or concanavalin A--Sepharose. Both molecules are heterogeneous when examined by polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate. As judged by its binding to columns of pea lectin, at least part of the heterogeneity of mouse thymocyte antigen T25 resides in its carbohydrate moiety.

scholarly journals C7 is expressed on endothelial cells as a trap for the assembling terminal complement complex and may exert anti-inflammatory function

Blood ◽  
2009 ◽  
Vol 113 (15) ◽  
pp. 3640-3648 ◽  
Author(s):  
Fleur Bossi ◽  
Lucia Rizzi ◽  
Roberta Bulla ◽  
Alessandra Debeus ◽  
Claudio Tripodo ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Blot Analysis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Complement Components ◽  
Albumin Leakage ◽  
Sds Page ◽  
Membrane Bound ◽  
Terminal Complement

Abstract We describe a novel localization of C7 as a membrane-bound molecule on endothelial cells (ECs). Data obtained by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE), Western blot analysis, Northern blot analysis, and mass spectrometry revealed that membrane-associated C7 (mC7) was indistinguishable from soluble C7 and was associated with vimentin on the cell surface. mC7 interacted with the other late complement components to form membrane-bound TCC (mTCC). Unlike the soluble SC5b-9, mTCC failed to stimulate ECs to express adhesion molecules, to secrete IL-8, and to induce albumin leakage through a monolayer of ECs, and more importantly protected ECs from the proinflammatory effect of SC5b-9. Our data disclose the possibility of a novel role of mC7 that acts as a trap for the late complement components to control excessive inflammation induced by SC5b-9.

scholarly journals Proteolytic and chemical dissection of the human erythrocyte glucose transporter

1984 ◽  
Vol 221 (1) ◽  
pp. 179-188 ◽  
Author(s):  
M T Cairns ◽  
D A Elliot ◽  
P R Scudder ◽  
S A Baldwin
Keyword(s):  
Human Erythrocyte ◽  
Glucose Transporter ◽  
Cytochalasin B ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Diffuse Band ◽  
Cytoplasmic Surface ◽  
Cytoplasmic Face ◽  
Membrane Bound ◽  
Beta Galactosidase

Treatment of the purified, reconstituted, human erythrocyte glucose transporter with trypsin lowered its affinity for cytochalasin B more than 2-fold, and produced two large, membrane-bound fragments. The smaller fragment (apparent Mr 18000) ran as a sharp band on sodium dodecyl sulphate (SDS)/polyacrylamide-gel electrophoresis. When the transporter was photoaffinity labelled with [4-3H]cytochalasin B before tryptic digestion, this fragment became radiolabelled and so probably comprises a part of the cytochalasin B binding site, which is known to lie on the cytoplasmic face of the erythrocyte membrane. In contrast, the larger fragment was not radiolabelled, and ran as a diffuse band on electrophoresis (apparent Mr 23000-42000). It could be converted to a sharper band (apparent Mr 23000) by treatment with endo-beta-galactosidase from Bacteroides fragilis and so probably contains one or more sites at which an oligosaccharide of the poly(N-acetyl-lactosamine) type is attached. Since the transporter bears oligosaccharides only on its extracellular domain, whereas trypsin is known to cleave the protein only at the cytoplasmic surface, this fragment must span the membrane. Cleavage of the intact, endo-beta-galactosidase-treated, photoaffinity-labelled protein at its cysteine residues with 2-nitro-5-thiocyanobenzoic acid yielded a prominent, unlabelled fragment of apparent Mr 38000 and several smaller fragments which stained less intensely on SDS/polyacrylamide gels. Radioactivity was found predominantly in a fragment of apparent Mr 15500. Therefore it appears that the site(s) labelled by [4-3H]cytochalasin B lies within the N-terminal or C-terminal third of the intact polypeptide chain.

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