scholarly journals Hemolytic Activity in Relation to the Photosynthetic System in Chattonella marina and Chattonella ovata

Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 336
Author(s):  
Ni Wu ◽  
Mengmeng Tong ◽  
Siyu Gou ◽  
Weiji Zeng ◽  
Zhuoyun Xu ◽  
...  
Keyword(s):  
Electron Transport ◽  
Hemolytic Activity ◽  
Electron Transport Chain ◽  
Energy Transport ◽  
Sufficient Conditions ◽  
Chattonella Marina ◽  
Chl A ◽  
Transport Chain ◽  
Hemolytic Toxin ◽  
Light Harvesting Antenna

Chattonella species, C. marina and C. ovata, are harmful raphidophycean flagellates known to have hemolytic effects on many marine organisms and resulting in massive ecological damage worldwide. However, knowledge of the toxigenic mechanism of these ichthyotoxic flagellates is still limited. Light was reported to be responsible for the hemolytic activity (HA) of Chattonella species. Therefore, the response of photoprotective, photosynthetic accessory pigments, the photosystem II (PSII) electron transport chain, as well as HA were investigated in non-axenic C. marina and C. ovata cultures under variable environmental conditions (light, iron and addition of photosynthetic inhibitors). HA and hydrogen peroxide (H2O2) were quantified using erythrocytes and pHPA assay. Results confirmed that% HA of Chattonella was initiated by light, but was not always elicited during cell division. Exponential growth of C. marina and C. ovata under the light over 100 µmol m−2 s−1 or iron-sufficient conditions elicited high hemolytic activity. Inhibitors of PSII reduced the HA of C. marina, but had no effect on C. ovata. The toxicological response indicated that HA in Chattonella was not associated with the photoprotective system, i.e., xanthophyll cycle and regulation of reactive oxygen species, nor the PSII electron transport chain, but most likely occurred during energy transport through the light-harvesting antenna pigments. A positive, highly significant relationship between HA and chlorophyll (chl) biosynthesis pigments, especially chl c2 and chl a, in both species, indicated that hemolytic toxin may be generated during electron/energy transfer through the chl c2 biosynthesis pathway.

On the Reaction between Chlorophyll-a, and its Primary Electron Donors in Photosynthesis

1971 ◽  
Vol 26 (11) ◽  
pp. 1171-1174 ◽  
Author(s):  
W. Haehnel ◽  
G. Döring ◽  
H. T. Witt
Keyword(s):  
Electron Transport ◽  
Electron Transport Chain ◽  
Equilibrium Constants ◽  
Reaction Times ◽  
Primary Electron ◽  
High Time Resolution ◽  
Chl A ◽  
Transport Chain ◽  
Rate Limiting ◽  
Reduced State

Electrons produced by Chl-aII in a short flash are finally transfered to Chl-ai after having passed several intermediates. The reaction between Chl-aI and its primary electron donators PD (probably Cyt-f and PC) has been studied by means of high time resolution flash photometry in isolated spinach chloroplasts with the following results:1. When PD are in the oxidized state, the reduction of Chl-aI⊕ takes place with the rate limiting reaction time of the electron transport chain (≈ 20 ms).2. When PD are in the reduced state, the reduction of Chl-aI⊕ takes place with the reaction times between the PD and Chl-ai. We found two half life times: one of about 200 μs and one of about 10 μs.The reduced state of PD is realized when weak monitoring light or hvII-preillumination is used.The two reaction times of ≈ 200 μs and of ≈ 10 µs are interpreted to represent the electron transfers between Cyt-f and Chl-aI and between PC and Chl-aI resp.Equilibrium constants of the electron transfer from PD to Chl-aI and the arrangement of the intermediates in the electron transport chain are discussed.

scholarly journals AB0031 T HELPER 17 CELLS WERE SIGNIFICANTLY DECREASED BY MITOCHONDRIAL ELECTRON TRANSPORT CHAIN COMPLEX INHIBITOR IN PATIENTS WITH RHEUMATOID ARTHRITIS

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1318.2-1318
Author(s):  
H. R. Lee ◽  
S. J. Yoo ◽  
J. Kim ◽  
I. S. Yoo ◽  
C. K. Park ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Electron Transport ◽  
Disease Activity ◽  
Th17 Cells ◽  
Electron Transport Chain ◽  
Chain Complex ◽  
Complex Iii ◽  
Mitochondrial Electron Transport Chain ◽  
Transport Chain ◽  
Healthy Control

Background:Reactive oxygen species (ROS) and T helper 17 (TH17) cells have been known to play an important role in the pathogenesis of rheumatoid arthritis (RA). However, the interrelationship between ROS and TH17 remains unclear in RAObjectives:To explore whether ROS affect TH17 cells in peripheral blood mononuclear cells (PBMC) of RA patients, we analyzed ROS expressions among T cell subsets following treatment with mitochondrial electron transport chain complex inhibitors.Methods:Blood samples were collected from 40 RA patients and 10 healthy adult volunteers. RA activity was divided according to clinical parameter DAS28. PBMC cells were obtained from the whole blood using lymphocyte separation medium density gradient centrifugation. Following PBMC was stained with Live/Dead stain dye, cells were incubated with antibodies for CD3, CD4, CD8, and CD25. After fixation and permeabilization, samples were stained with antibodies for FoxP3 and IL-17A. MitoSox were used for mitochondrial specific staining.Results:The frequency of TH17 cells was increased by 4.83 folds in moderate disease activity group (5.1>DAS28≥3.2) of RA patients compared to healthy control. Moderate RA activity patients also showed higher ratio of TH17/Treg than healthy control (3.57 folds). All RA patients had elevated expression of mitochondrial specific ROS than healthy control. When PBMC cells were treated with 2.5uM of antimycin A (mitochondrial electron transport chain complex III inhibitor) for 16 h, the frequency of TH17 cells was significantly decreased.Conclusion:The mitochondrial electron transport chain complex III inhibitor markedly downregulated the frequency of TH17 cells in moderate disease activity patients with RA. These findings provide a novel approach to regulate TH17 function in RA through mitochondrial metabolism related ROS production.References:[1]Szekanecz, Z., et al., New insights in synovial angiogenesis. Joint Bone Spine, 2010. 77(1): p. 13-9.[2]Prevoo, M.L., et al., Modified disease activity scores that include twenty-eight-joint counts. Development and validation in a prospective longitudinal study of patients with rheumatoid arthritis. Arthritis Rheum, 1995. 38(1): p. 44-8.Disclosure of Interests:None declared

scholarly journals Effects of Different Planting Densities on Photosynthesis in Maize Determined via Prompt Fluorescence, Delayed Fluorescence and P700 Signals

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 276
Author(s):  
Wanying Chen ◽  
Bo Jia ◽  
Junyu Chen ◽  
Yujiao Feng ◽  
Yue Li ◽  
...  
Keyword(s):  
Electron Transport ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Electron Transport Chain ◽  
Plant Density ◽  
Photosynthetic Electron Transport ◽  
Planting Density ◽  
Strong Impact ◽  
Photosynthetic Electron Transport Chain ◽  
Transport Chain

The mutual shading among individual field-grown maize plants resulting from high planting density inevitably reduces leaf photosynthesis, while regulating the photosynthetic transport chain has a strong impact on photosynthesis. However, the effect of high planting density on the photosynthetic electron transport chain in maize currently remains unclear. In this study, we simultaneously measured prompt chlorophyll a fluorescence (PF), modulated 820 nm reflection (MR) and delayed chlorophyll a fluorescence (DF) in order to investigate the effect of high planting density on the photosynthetic electron transport chain in two maize hybrids widely grown in China. PF transients demonstrated a gradual reduction in their signal amplitude with increasing planting density. In addition, high planting density induced positive J-step and G-bands of the PF transients, reduced the values of PF parameters PIABS, RC/CSO, TRO/ABS, ETO/TRO and REO/ETO, and enhanced ABS/RC and N. MR kinetics showed an increase of their lowest point with increasing high planting density, and thus the values of MR parameters VPSI and VPSII-PSI were reduced. The shapes of DF induction and decay curves were changed by high planting density. In addition, high planting density reduced the values of DF parameters I1, I2, L1 and L2, and enhanced I2/I1. These results suggested that high planting density caused harm on multiple components of maize photosynthetic electron transport chain, including an inactivation of PSII RCs, a blocked electron transfer between QA and QB, a reduction in PSI oxidation and re-reduction activities, and an impaired PSI acceptor side. Moreover, a comparison between PSII and PSI activities demonstrated the greater effect of plant density on the former.

scholarly journals Anticancer gold(iii)-bisphosphine complex alters the mitochondrial electron transport chain to induce in vivo tumor inhibition

2021 ◽  
Author(s):  
Jong Hyun Kim ◽  
Samuel Ofori ◽  
Sean Parkin ◽  
Hemendra Vekaria ◽  
Patrick G. Sullivan ◽  
...  
Keyword(s):  
Electron Transport ◽  
Metal Complexes ◽  
Electron Transport Chain ◽  
Chemical Diversity ◽  
Mitochondrial Electron Transport Chain ◽  
Generate Functional ◽  
Tumor Inhibition ◽  
Transport Chain

Expanding the chemical diversity of metal complexes provides a robust platform to generate functional bioactive reagents.

A large portion of the astrocyte proteome is dedicated to perivascular endfeet, including critical components of the electron transport chain

2021 ◽  
pp. 0271678X2110041
Author(s):  
Jesse A Stokum ◽  
Bosung Shim ◽  
Weiliang Huang ◽  
Maureen Kane ◽  
Jesse A Smith ◽  
...  
Keyword(s):  
Electron Transport ◽  
Electron Transport Chain ◽  
Glycogen Storage ◽  
Subcellular Compartment ◽  
Diffusion Limited ◽  
Transport Chain ◽  
Critical Components ◽  
And Diffusion ◽  
Ubiquitous Presence ◽  
Astrocyte Endfeet

The perivascular astrocyte endfoot is a specialized and diffusion-limited subcellular compartment that fully ensheathes the cerebral vasculature. Despite their ubiquitous presence, a detailed understanding of endfoot physiology remains elusive, in part due to a limited understanding of the proteins that distinguish the endfoot from the greater astrocyte body. Here, we developed a technique to isolate astrocyte endfeet from brain tissue, which was used to study the endfoot proteome in comparison to the astrocyte somata. In our approach, brain microvessels, which retain their endfoot processes, were isolated from mouse brain and dissociated, whereupon endfeet were recovered using an antibody-based column astrocyte isolation kit. Our findings expand the known set of proteins enriched at the endfoot from 10 to 516, which comprised more than 1/5th of the entire detected astrocyte proteome. Numerous critical electron transport chain proteins were expressed only at the endfeet, while enzymes involved in glycogen storage were distributed to the somata, indicating subcellular metabolic compartmentalization. The endfoot proteome also included numerous proteins that, while known to have important contributions to blood-brain barrier function, were not previously known to localize to the endfoot. Our findings highlight the importance of the endfoot and suggest new routes of investigation into endfoot function.

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