Polyamines (PAs) are small metabolites that are produced and oxidized in chloroplasts with an obscure mode of action. Recently, we showed that qE is stimulated by PAs in higher plants (Nicotiana tabacum) and in genetically modified plants with elevated thylakoid-associated PAs (Ioannidis and Kotzabasis Biochim Biophys Acta 1767:1371-1382, 2007; Ioannidis et al. Biochim Biophys Acta 1787:1215-1222, 2009). Here, we investigated further their quenching properties both in vivo in green algae and in vitro is isolated LHCII. In vivo spermine up-regulates NPQ in Scenedesums obliquus about 30%. In vitro putrescine--the obligatory metabolic precursor of PAs--has a marginal quenching effect, while spermidine and spermine exhibit strong quenching abilities in isolated LHCII up to 40%. Based on available 3D models of LHCII we report a special cavity of about 600 Å(3) and a near-by larger pocket in the trimeric LHCII that could be of importance for the stimulation of qE by amines.
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Biochim Biophys Acta Bioenerg
January 2025
Buck Institute for Research on Aging, Novato, CA, United States of America. Electronic address:
To professional bioenergeticists, the thermodynamic and kinetic constraints on mitochondrial function are self-evident. It is therefore profoundly concerning that high-profile cell biology papers continue to appear containing fundamental bioenergetic errors that appear to have evaded the scrutiny of the principal investigator, co-authors, editors and, apparently, at least some of the referees. The problem is not new, and seems to stem from a perception that bioenergetics is a 'difficult' subject, both at undergraduate level, if it is taught in any depth, and in research, where cell biologists are faced with biophysical concepts such as protonmotive force, ion flux, redox potential and Gibbs free energy.
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January 2025
Department of Surgery and Leiden Transplant Center, Leiden University Medical Center, Leiden, the Netherlands. Electronic address:
Ischemia-reperfusion (IR) injury remains a major contributor to organ dysfunction following transient ischemic insults. Although numerous interventions have been found effective to reduce IR injury in preclinical models, none of these therapies have been successfully translated to the clinical setting. In the context of the persistent translational gap, we systematically investigated the mechanisms implicated in IR injury using kidney donation and transplantation as a clinical model of IR.
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January 2025
Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA. Electronic address:
The human mitochondrial nicotinamide nucleotide transhydrogenase (NNT) uses the proton motive force to drive hydride transfer from NADH to NADP and is a major contributor to the generation of mitochondrial NADPH. NNT plays a critical role in maintaining cellular redox balance. NNT-deficiency results in oxidative damage and its absence results in familial glucocorticoid deficiency.
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January 2025
Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada; Cross Cancer Institute, Alberta Health Services, Edmonton, Alberta, Canada. Electronic address:
Lymphedema is characterized by the swelling of extremities due to the accumulation of interstitial fluids. It is a painful and devastating disease that increases the risk of infections and destroys patients' quality of life. Secondary lymphedema is caused by damage to the lymphatic system due to infections, obesity, surgery, and cancer treatments.
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January 2025
Center of Interventional Radiology & Vascular Surgery, Department of Radiology, Zhongda Hospital, Medical School, Southeast University, Nanjing 210009, Jiangsu, PR China. Electronic address:
This study investigates the role of SPINK1 in liver cancer and its regulatory relationship with FOXM1. Using differential gene analysis in the GEO database, SPINK1 was identified as overexpressed in liver cancer tissues and associated with poor prognosis, confirmed via PCR. Functional assays demonstrated that SPINK1 knockdown reduced proliferation, migration, and invasion in liver cancer cells, while promoting apoptosis.
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