ROLE OF PHOSPHOLIPIDS IN OXIDATIVE PHOSPHORYLATION AND MITOCHONDRIAL STRUCTURE

1959 ◽  
Vol 37 (8) ◽  
pp. 989-998 ◽  
Author(s):  
E. Petrushka ◽  
J. H. Quastel ◽  
P. G. Scholefield

The addition of small amounts (50 μg protein) of heated snake venom to respiring preparations of mitochondria from rat liver or kidney brings about an uncoupling of oxidation from phosphorylation as measured by a fall in the P/O ratio. When larger amounts (250 μg protein) of heated venom are added a rapid decline in the respiratory activity eventually takes place which coincides with a breakdown in the mitochondrial structure. On addition of smaller amounts (e.g. 7.5 μg protein) of heated venom to liver or kidney mitochondria there occurs a release of soluble proteins including enzymes, e.g. ATP-ase.Various phospholipids are able to exert a specific protective effect against the uncoupling action of heated venom. Albumin exhibits a non-specific effect but glutathionine, which helps to maintain the respiratory activity of mitochondria in the presence of heated venom, does not prevent the accompanying fall in the P/O ratio.The importance of the structural integrity of mitochondria for their enzymic activities is discussed, special reference being made to the role of phospholipids.

1959 ◽  
Vol 37 (1) ◽  
pp. 989-998 ◽  
Author(s):  
E. Petrushka ◽  
J. H. Quastel ◽  
P. G. Scholefield

The addition of small amounts (50 μg protein) of heated snake venom to respiring preparations of mitochondria from rat liver or kidney brings about an uncoupling of oxidation from phosphorylation as measured by a fall in the P/O ratio. When larger amounts (250 μg protein) of heated venom are added a rapid decline in the respiratory activity eventually takes place which coincides with a breakdown in the mitochondrial structure. On addition of smaller amounts (e.g. 7.5 μg protein) of heated venom to liver or kidney mitochondria there occurs a release of soluble proteins including enzymes, e.g. ATP-ase.Various phospholipids are able to exert a specific protective effect against the uncoupling action of heated venom. Albumin exhibits a non-specific effect but glutathionine, which helps to maintain the respiratory activity of mitochondria in the presence of heated venom, does not prevent the accompanying fall in the P/O ratio.The importance of the structural integrity of mitochondria for their enzymic activities is discussed, special reference being made to the role of phospholipids.


2009 ◽  
Vol 18 (3) ◽  
pp. 172-178 ◽  
Author(s):  
Kate E. A. Saunders ◽  
Keith Hawton

AbstractThe potential role of psychopharmacology in suicide prevention is often minimised. This may to some extent reflect that few medication trials have specifically focussed on prevention of suicidal behaviour – indeed this outcome is often not reported in trials. However, there is reasonably strong evidence that lithium may reduce risk of suicide, the postulated mechanism being a specific effect on aggression. Evidence is lacking with regard to any protective effect of other mood stabilizers. Clozapine may reduce suicidal behaviour in patients with schizophrenia, with reduction of affective symptoms being a possible explanation. The role of antidepressants in relation to suicide risk is highly controversial, especially in children and adolescents. It is unclear whether minor tranquillizers or hypnotics can assist in suicide prevention, although they can reduce the anxiety symptoms that may occur during initial treatment with SSRI antidepressants. Itis also uncertain whether psychopharmacology has a role in preventing suicidal behaviour in people with personality disorders. Despite the limitations of the evidence we contend that suicide risk should be an important factor in deciding when and what to prescribe.Declaration of Interest: We have no interests to declare.


Genetics ◽  
2002 ◽  
Vol 160 (4) ◽  
pp. 1375-1387
Author(s):  
Emmanuelle M D Martini ◽  
Scott Keeney ◽  
Mary Ann Osley

Abstract To investigate the role of the nucleosome during repair of DNA damage in yeast, we screened for histone H2B mutants that were sensitive to UV irradiation. We have isolated a new mutant, htb1-3, that shows preferential sensitivity to UV-C. There is no detectable difference in bulk chromatin structure or in the number of UV-induced cis-syn cyclobutane pyrimidine dimers (CPD) between HTB1 and htb1-3 strains. These results suggest a specific effect of this histone H2B mutation in UV-induced DNA repair processes rather than a global effect on chromatin structure. We analyzed the UV sensitivity of double mutants that contained the htb1-3 mutation and mutations in genes from each of the three epistasis groups of RAD genes. The htb1-3 mutation enhanced UV-induced cell killing in rad1Δ and rad52Δ mutants but not in rad6Δ or rad18Δ mutants, which are defective in postreplicational DNA repair (PRR). When combined with other mutations that affect PRR, the histone mutation increased the UV sensitivity of strains with defects in either the error-prone (rev1Δ) or error-free (rad30Δ) branches of PRR, but did not enhance the UV sensitivity of a strain with a rad5Δ mutation. When combined with a ubc13Δ mutation, which is also epistatic with rad5Δ, the htb1-3 mutation enhanced UV-induced cell killing. These results suggest that histone H2B acts in a novel RAD5-dependent branch of PRR.


Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 562
Author(s):  
Miliça Ristovski ◽  
Danny Farhat ◽  
Shelly Ellaine M. Bancud ◽  
Jyh-Yeuan Lee

Lipid composition in cellular membranes plays an important role in maintaining the structural integrity of cells and in regulating cellular signaling that controls functions of both membrane-anchored and cytoplasmic proteins. ATP-dependent ABC and P4-ATPase lipid transporters, two integral membrane proteins, are known to contribute to lipid translocation across the lipid bilayers on the cellular membranes. In this review, we will highlight current knowledge about the role of cholesterol and phospholipids of cellular membranes in regulating cell signaling and how lipid transporters participate this process.


2021 ◽  
Vol 9 (2) ◽  
pp. 226
Author(s):  
Milan Jirků ◽  
Zuzana Lhotská ◽  
Lucia Frgelecová ◽  
Oldřiška Kadlecová ◽  
Klára Judita Petrželková ◽  
...  

Colonization by the benign tapeworm, Hymenolepis diminuta, has been associated with a reduction in intestinal inflammation and changes in bacterial microbiota. However, the role of microbiota in the tapeworm anti-inflammatory effect is not yet clear, and the aim of this study was to determine whether disruption of the microflora during worm colonization can affect the course of intestinal inflammation. We added a phase for disrupting the intestinal microbiota using antibiotics to the experimental design for which we previously demonstrated the protective effect of H. diminuta. We monitored the immunological markers, clinical parameters, bacterial microbiota, and histological changes in the colon of rats. After a combination of colonization, antibiotics, and colitis induction, we had four differently affected experimental groups. We observed a different course of the immune response in each group, but no protective effect was found. Rats treated with colonization and antibiotics showed a strong induction of the Th2 response as well as a significant change in microbial diversity. The microbial results also revealed differences in the richness and abundance of some bacterial taxa, influenced by various factors. Our data suggest that interactions between the tapeworm and bacteria may have a major impact on its protective effect.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yawei Wang ◽  
Binlin Tang ◽  
Lei Long ◽  
Peng Luo ◽  
Wei Xiang ◽  
...  

AbstractPro-inflammatory activation of adipose tissue macrophages (ATMs) is causally linked to obesity and obesity-associated disorders. A number of studies have demonstrated the crucial role of mitochondrial metabolism in macrophage activation. However, there is a lack of pharmaceutical agents to target the mitochondrial metabolism of ATMs for the treatment of obesity-related diseases. Here, we characterize a near-infrared fluorophore (IR-61) that preferentially accumulates in the mitochondria of ATMs and has a therapeutic effect on diet-induced obesity as well as obesity-associated insulin resistance and fatty liver. IR-61 inhibits the classical activation of ATMs by increasing mitochondrial complex levels and oxidative phosphorylation via the ROS/Akt/Acly pathway. Taken together, our findings indicate that specific enhancement of ATMs oxidative phosphorylation improves chronic inflammation and obesity-related disorders. IR-61 might be an anti-inflammatory agent useful for the treatment of obesity-related diseases by targeting the mitochondria of ATMs.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Hong Wang ◽  
Aiping Duan ◽  
Jing Zhang ◽  
Qi Wang ◽  
Yuexian Xing ◽  
...  

AbstractElucidating transcription mediated by the glucocorticoid receptor (GR) is crucial for understanding the role of glucocorticoids (GCs) in the treatment of diseases. Podocyte is a useful model for studying GR regulation because GCs are the primary medication for podocytopathy. In this study, we integrated data from transcriptome, transcription factor binding, histone modification, and genome topology. Our data reveals that the GR binds and activates selective regulatory elements in podocyte. The 3D interactome captured by HiChIP facilitates the identification of remote targets of GR. We found that GR in podocyte is enriched at transcriptional interaction hubs and super-enhancers. We further demonstrate that the target gene of the top GR-associated super-enhancer is indispensable to the effective functioning of GC in podocyte. Our findings provided insights into the mechanisms underlying the protective effect of GCs on podocyte, and demonstrate the importance of considering transcriptional interactions in order to fine-map regulatory networks of GR.


Sign in / Sign up

Export Citation Format

Share Document