The Photosynthetic Apparatus of Ectothiorhodospira halochloris 3. Effect of Proteolytic Digestion on the Photoactivity

1986 ◽  
Vol 41 (9-10) ◽  
pp. 873-880 ◽  
Author(s):  
R. Steiner ◽  
B. Kalumenos ◽  
H. Scheer
Keyword(s):  
Molecular Weight ◽  
Reaction Center ◽  
Photosynthetic Apparatus ◽  
Photochemical Activity ◽  
Proteinase K ◽  
Proteolytic Digestion ◽  
Polypeptide Composition ◽  
Difference Spectra ◽  
Ectothiorhodospira Halochloris ◽  
The One

Abstract Photsynthetic membranes of Rhodopseudomonas virids and Ectothiorhodospira halochloris were treated with proteinase K. The photochemical activity (light minus dark difference spectra) were compared to the polypeptide composition (SDS-polyacrylamide gel analysis). In E. halo­chloris, difference bands appear at 806 (+), 838 (+) and 854 nm (-) . All three decrease in intensity upon incubation with proteinase K., but this decrease is much slower than the proteolysis of both the reaction center and antenna related polypeptides. Photochemical activity remains high as long as a small part of the RC and two lower molecular weight polypeptides M* (22.0 kDa) and B* (15.3 kDa) are present. The M subunit is the most stable polypeptide in the RC of Rp. viridis too, and the photochemical activity is related to the remainder of this and to the one newly formed polypeptide (15.3 kDa), but doesn’t show the typical absorption shift of the antenna (B 800/1020 → B 800/960). The results are discussed quantitatively and compared to those obtained from Bchl α containing organisms.

The Photosynthetic Apparatus of Ectothiorhodospira halochloris 2. Accessibility of the Membrane Polypeptides to Partial Proteolysis and Antenna Polypeptide Assignments to Specific Chromophores

1986 ◽  
Vol 41 (5-6) ◽  
pp. 571-578 ◽  
Author(s):  
R. Steiner ◽  
A. Angerhofer ◽  
H. Scheer
Keyword(s):  
Absorption Band ◽  
Photosynthetic Bacteria ◽  
Photosynthetic Apparatus ◽  
Reaction Centers ◽  
Proteinase K ◽  
Spectral Changes ◽  
Membrane Surfaces ◽  
Sds Page ◽  
Ectothiorhodospira Halochloris ◽  
Cytoplasmic Side

E. halochloris thylakoids and spheroplasts were treated with trypsin, thermolysin or proteinase K to determine which proteins are exposed at the different membrane surfaces. Based on SDS polyacrylamide analysis, all 9 polypeptides are exposed on the cytoplasmic side. Only one (28 kDa) is accessible from the periplasmic side. This polypeptide is generally isolated as the H-subunit of the reaction centers of photosynthetic bacteria, but is in the case of E. halochloris rather isolated with the antenna (B 800/1020) (Steiner and Scheer, Biochim . Biophys. Acta 807, 278, 1983).Proteolysis is accompanied by a shift of the absorption band at longest wavelengths from 1020 to 960 nm (B 800/960), which upon standing is shifted further to 680 nm (“B” 800/680). The spectral changes are similar to the ones reported earlier for treatment with acid, and are also inducible with urea. The correlation of SDS-PAGE and absorption spectroscopy shows, that the chroophores absorbing at 1020 nm are transformed sim ultaneously with the degradation of the 6.5 kDa (=α) polypeptide.

Changes in the Stoichiometry of Photosystem II Components as an Adaptive Response to High-Light and Low-Light Conditions during Growth

1986 ◽  
Vol 41 (5-6) ◽  
pp. 597-603 ◽  
Author(s):  
Aloysius Wild ◽  
Matthias Höpfner ◽  
Wolfgang Rühle ◽  
Michael Richter
Keyword(s):  
Photosystem Ii ◽  
Functional Organization ◽  
Photosynthetic Apparatus ◽  
High Light ◽  
Molar Ratio ◽  
Light Conditions ◽  
Low Light ◽  
Pigment System ◽  
Transport Chain ◽  
The One

The effect of different growth light intensities (60 W·m-2, 6 W·m-2) on the performance of the photosynthetic apparatus of mustard plants (Sinapis alba L.) was studied. A distinct decrease in photosystem II content per chlorophyll under low-light conditions compared to high-light conditions was found. For P-680 as well as for Oᴀ and Oв protein the molar ratio between high-light and low-light plants was 1.4 whereas the respective concentrations per chlorophyll showed some variations for P-680 and Oᴀ on the one and Oв protein on the other hand.In addition to the study of photosystem II components, the concentrations of PQ, Cyt f, and P-700 were measured. The light regime during growth had no effect on the amount of P-700 per chlorophyll but there were large differences with respect to PQ and Cyt f. The molar ratio for Cyt f and PQ between high- and low-light leaves was 2.2 and 1.9, respectively.Two models are proposed, showing the functional organization of the pigment system and the electron transport chain in thylakoids of high-light and low-light leaves of mustard plants.

Polypeptide composition and organization of the sea urchin extraembryonic hyaline layer

1990 ◽  
Vol 68 (9) ◽  
pp. 1083-1089 ◽  
Author(s):  
John J. Robinson
Keyword(s):  
Embryonic Development ◽  
Sea Urchin ◽  
Organization Development ◽  
Structural Organization ◽  
Protein Composition ◽  
Ruthenium Red ◽  
Proteinase K ◽  
Polypeptide Composition ◽  
Layer Composition ◽  
Precipitable Protein

The protein composition and organization of the sea urchin extraembryonic hyaline layer was examined. Hyalin and a polypeptide of 45 kilodaltons (kDa) were present in hyaline layers isolated from 1-h-old embryos through to the pluteus larva stage. In contrast, several polypeptide species ranging in size from 175 to 32 kDa either decreased in amount or disappeared from the layer as embryonic development proceeded. Concomitant with the changes in composition, hyaline layers became progressively more refractory to dissolution by washing in Ca2+, Mg2+-free seawater. Incubation of intact layers, isolated from 1-h-old embryos, with proteinase K resulted in the selective digestion of hyalin and was accompanied by release of the 45-kDa polypeptide from the layers. Washing intact layers in 20 mM Tris (pH 8.0) also resulted in the selective removal of hyalin and the 45-kDa polypeptide. The Ca2+-precipitable protein hyalin, alone among the hyaline layer polypeptides, bound the Ca2+-antagonist ruthenium red. These results suggest a structural organization within the hyaline layer that is both heterogenous and dynamic throughout embryonic development.Key words: hyaline layer, composition, organization, development.

Detection and partial characterization of extracellular inducers of persistence in Staphylococcus epidermidis and Staphylococcus aureus

2021 ◽  
Vol 70 (6) ◽  
Author(s):  
Elyse C. Curry ◽  
Ryan G. Hart ◽  
Danni Y. Habtu ◽  
Neal R. Chamberlain
Keyword(s):  
Molecular Weight ◽  
Staphylococcus Aureus ◽  
Staphylococcus Epidermidis ◽  
Type Species ◽  
Proteinase K ◽  
Partial Characterization ◽  
Content Type ◽  
Link Type ◽  
Inducing Factors

Introduction. This study describes the identification and partial characterization of persistence-inducing factors (PIFs) from staphylococci. Hypothesis/Gap Statement. Increases in persisters during mid-log phase growth indicate that quorum-sensing factors might be produced by staphylococci. Aim. To identify and partially characterize PIFs from Staphylococcus epidermidis RP62A and Staphylococcus aureus SH1000. Methodology. Others have demonstrated a significant increase in persister numbers during mid-log phase. Inducers of this mid-log increase have yet to be identified in staphylococci. Optical density at 600 nm (OD600) was used instead of time to determine when persister numbers increased during logarithmic growth. Concentrated culture filtrates (CCFs) from S. epidermidis and S. aureus were obtained at various OD600s and following incubation at 16 h. The CCFs were used to develop a PIF assay. The PIF assay was used to partially characterize PIF from S. epidermidis and S. aureus for sizing of PIF activity, temperature and protease sensitivity and inter-species communications. Results. The optimal OD600s for S. epidermidis and S. aureus PIF assays were 2.0 and 0.5, respectively. The highest PIF activity for both species was from CCF following incubation overnight (16 h). S. epidermidis ’ PIF activity was decreased by storage at 4 oC but not at 20 oC (16 h), 37 oC (1 h) or 100 oC (15 min). S. aureus ’ PIF activity was decreased following storage at 4 oC (2 weeks) and after boiling at 100 oC for 5 min but not after incubation at 37 oC (1 h). PIF activity from both species went through a 3000 molecular weight cutoff ultrafilter. Proteinase K treatment of S. aureus PIF decreased activity but did not decrease the PIF activity of S. epidermidis . PIF from S. epidermidis did not increase persisters when used to treat S. aureus cells and nor did PIF from S. aureus increase persisters when used to treat S. epidermidis cells. Conclusions. Attempts to discover PIFs for staphylococci were unsuccessful due to the time-based means used to identify mid-log. Both staphylococcal species produce extracellular, low-molecular-weight inducers of persistence when assayed using an OD600 -based PIF assay.

scholarly journals Novel Cell Death-Inducing Elicitors fromPhytophthora palmivoraPromote Infection onHevea brasiliensis

2019 ◽  
Vol 109 (10) ◽  
pp. 1769-1778 ◽  
Author(s):  
Sittiporn Pettongkhao ◽  
Nunta Churngchow
Keyword(s):  
Molecular Weight ◽  
Cell Death ◽  
High Molecular Weight ◽  
Rubber Tree ◽  
Defense Responses ◽  
Proteinase K ◽  
Phytophthora Palmivora ◽  
Tree Leaves ◽  
Beta Glucan ◽  
Tobacco Leaves

Elicitors play an important role in plant and pathogen interactions. The discovery of new elicitors and their effects on plant defense responses is significant and challenging. In this study, we investigated novel elicitors from Phytophthora palmivora and their effects on plant defenses. A crude elicitor isolated by ethanol precipitation from culture filtrates of P. palmivora induced cell death in tobacco leaves. When tobacco leaves were infiltrated with this cell death-inducing elicitor, the accumulations of H2O2, salicylic acid (SA), scopoletin (Scp), and abscisic acid (ABA) were detected. Accumulations of SA, Scp, and ABA were also induced in rubber tree leaves. P. palmivora infection significantly increased in rubber tree leaves pretreated with the elicitor and cotreated with the elicitor and zoospores of P. palmivora. This elicitor can be described as compound elicitor because Fourier-transform infrared spectroscopy revealed that it consisted of both polysaccharide and protein. We also found that the cell death effect caused by this compound elicitor was completely neutralized by Proteinase K. The compound elicitor was composed of four fractions which were beta-glucan, high-molecular-weight glycoprotein, broad-molecular-weight glycoprotein and 42-kDa protein. Interestingly, the broad-molecular-weight glycoprotein caused the highest level of cell death in tobacco leaves, while the beta-glucan had no effect. The high-molecular-weight glycoprotein, broad-molecular-weight glycoprotein and 42-kDa protein fractions not only caused cell death in tobacco leaves but also induced high levels of SA accumulation. Furthermore, these three fractions clearly promoted P. palmivora infection of rubber tree leaves.

Synthesis and chiroptical properties of cylindrical macrocycles comprising two calix[3]aramide moieties

2020 ◽  
Vol 18 (2) ◽  
pp. 230-236 ◽  
Author(s):  
Yuuki Saito ◽  
Misa Satake ◽  
Ryuichi Mori ◽  
Misaki Okayasu ◽  
Hyuma Masu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Chiroptical Properties ◽  
Amide Coupling ◽  
One Step ◽  
The One

Novel chiral macrocyclic aromatic amides of medium molecular weight were synthesized by the one-step amide coupling of a bis(alkylamino)terphenyl diacid as monomer.

The structure and function of grana-free thylakoid membranes in gerontoplasts of senescent leaves of vicia faba l.

1988 ◽  
Vol 43 (1-2) ◽  
pp. 149-154 ◽  
Author(s):  
H. Oskar Schmidt
Keyword(s):  
Vicia Faba ◽  
Thylakoid Membranes ◽  
Photochemical Activity ◽  
Structure And Function ◽  
Polypeptide Composition ◽  
Light Harvesting Complex ◽  
Vicia Faba L ◽  
Light Protection ◽  
Flotation Method ◽  
And Function

In the course of yellowing (senescence) the leaves of Vicia faba L. lose 95% of their chlorophyll. Gerontoplasts develop from chloroplasts and aggregate with the pycnotic mitochondria and the cell nucleus in the senescent cells (organelle aggregation). The gerontoplasts contain only a few, unstacked thylakoid membranes but a large number of carotinoid-containing plastoglobuli, which after the degration of chlorophyll presumably assume the light protection of the cells. The thylakoid membranes of the gerontoplasts were isolated by means of a flotation method. Their polypeptide composition is characterized by a high proportion of light-harvesting complex. Evidence of relatively high photochemical activity shows that functional thylakoid membranes are present in the premortal senescence state of leaves and this suggests that there is functional compartmentation of the hydrolytic processes in this stage of the leaves’ development

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