scholarly journals Energy conservation involving 2 respiratory circuits

2019 ◽  
Vol 117 (2) ◽  
pp. 1167-1173 ◽  
Author(s):  
Marie Charlotte Schoelmerich ◽  
Alexander Katsyv ◽  
Judith Dönig ◽  
Timothy J. Hackmann ◽  
Volker Müller

Chemiosmosis and substrate-level phosphorylation are the 2 mechanisms employed to form the biological energy currency adenosine triphosphate (ATP). During chemiosmosis, a transmembrane electrochemical ion gradient is harnessed by a rotary ATP synthase to phosphorylate adenosine diphosphate to ATP. In microorganisms, this ion gradient is usually composed of H+, but it can also be composed of Na+. Here, we show that the strictly anaerobic rumen bacterium Pseudobutyrivibrio ruminis possesses 2 ATP synthases and 2 distinct respiratory enzymes, the ferredoxin:NAD+ oxidoreductase (Rnf complex) and the energy-converting hydrogenase (Ech complex). In silico analyses revealed that 1 ATP synthase is H+-dependent and the other Na+-dependent, which was validated by biochemical analyses. Rnf and Ech activity was also biochemically identified and investigated in membranes of P. ruminis. Furthermore, the physiology of the rumen bacterium and the role of the energy-conserving systems was investigated in dependence of 2 different catabolic pathways (the Embden–Meyerhof–Parnas or the pentose–phosphate pathway) and in dependence of Na+ availability. Growth of P. ruminis was greatly stimulated by Na+, and a combination of physiological, biochemical, and transcriptional analyses revealed the role of the energy conserving systems in P. ruminis under different metabolic scenarios. These data demonstrate the use of a 2-component ion circuit for H+ bioenergetics and a 2nd 2-component ion circuit for Na+ bioenergetics in a strictly anaerobic rumen bacterium. In silico analyses infer that these 2 circuits are prevalent in a number of other strictly anaerobic microorganisms.

Oncotarget ◽  
2016 ◽  
Vol 7 (16) ◽  
pp. 22865-22872 ◽  
Author(s):  
Alberto Ocaña ◽  
Javier Pérez-Peña ◽  
Ana Alcaraz-Sanabria ◽  
Verónica Sánchez-Corrales ◽  
Cristina Nieto-Jiménez ◽  
...  

Author(s):  
Sunil Thomas

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the disease COVID-19 that has decimated the health and economy of our planet. The virus causes the disease not only in people but also in companion and wild animals. People with diabetes are at risk of the disease. As yet we do not know why the virus is highly successful in causing the pandemic within 3 months of its first report. The structural proteins of SARS include, membrane glycoprotein (M), envelope protein (E), nucleocapsid protein (N) and the spike protein (S). The structure and function of the most abundant structural protein of SARS-CoV-2, the membrane (M) glycoprotein is not fully understood. Using in silico analyses we determined the structure and potential function of the M protein. In silico analyses showed that the M protein of SARS-CoV-2 has a triple helix bundle, form a single 3-transmembrane domain (TM), and are homologous to the prokaryotic sugar transport protein semiSWEET. The advantage and role of sugar transporter like structures in viruses are unknown. If they are involved in energy metabolism, they may aid in the rapid proliferation and replication of the virus. Biological experiments should be performed to validate the presence and function of the semiSWEET sugar transporter.


2020 ◽  
Vol 11 (1) ◽  
pp. 143-152 ◽  
Author(s):  
Sunil Nath

AbstractThe mitochondrial permeability transition (MPT) has been one of the longstanding enigmas in biology. Its cause is currently at the center of an extensive scientific debate, and several hypotheses on its molecular nature have been put forward. The present view holds that the transition arises from the opening of a high-conductance channel in the energy-transducing membrane, the permeability transition pore (PTP), also called the mitochondrial megachannel or the multiconductance channel (MMC). Here, the novel hypothesis is proposed that the aqueous access channels at the interface of the c-ring and the a-subunit of FO in the FOF1-ATP synthase are repurposed during induction of apoptosis and constitute the elusive PTP/ MMC. A unifying principle based on regulation by local potentials is advanced to rationalize the action of the myriad structurally and chemically diverse inducers and inhibitors of PTP/MMC. Experimental evidence in favor of the hypothesis and its differences from current models of PTP/MMC are summarized. The hypothesis explains in considerable detail how the binding of Ca2+ to a β-catalytic site (site 3) in the F1 portion of ATP synthase triggers the opening of the PTP/MMC. It is also shown to connect to longstanding proposals within Nath’s torsional mechanism of energy transduction and ATP synthesis as to how the binding of MgADP to site 3 does not induce PTP/MMC, but instead catalyzes physiological ATP synthesis in cell life. In the author’s knowledge, this is the first model that explains how Ca2+ transforms the FOF1-ATP synthase from an exquisite energy-conserving enzyme in cell life into an energy-dissipating structure that promotes cell death. This has major implications for basic as well as for clinical research, such as for the development of drugs that target the MPT, given the established role of PTP/MMC dysregulation in cancer, ischemia, cardiac hypertrophy, and various neurodegenerative diseases.


Genetika ◽  
2021 ◽  
Vol 53 (1) ◽  
pp. 65-78
Author(s):  
Farinaz Ziaee ◽  
Mohammadreza Hajjari ◽  
Seyed Kazeminezhad ◽  
Mehrdad Behmanesh

SNHG7, as a member of the small nucleolar host gene family, is a recently identified long non-coding RNA (lncRNA). Different reports have identified the SNHGs as competing endogenous RNAs (ceRNAs) sponging miRNAs with a role in cancer progression. However, the biological functions of SNHG7 in the colorectal cancer (CRC) remained to be almost unknown. The current in silico study was aimed to find the potential role of SNHG7 in the CRC development. In this study, we showed the up-regulation of SNHG7 as well as its potential correlation with miRNAs, including mir-193a-5p and mir-485-5P. We hypothesized that SNHG7 modulates these miRNAs availability by acting as a molecular sponge. Our findings showed the potential targets of these miRNAs by studying different databases as well as in silico analyses. In summary, we found SNHG7 as a potential ceRNA which may be a promising biomarker for diagnostic and therapeutic target in CRC.


2020 ◽  
Author(s):  
Abhigyan Choudhury ◽  
Nabarun Chandra Das ◽  
Ritwik Patra ◽  
Suprabhat Mukherjee

AbstractThe worldwide outbreak of COVID-19 pandemic caused by SARS-CoV-2 leads to loss of mankind and global economic stability. The continuous spreading of the disease and its pathogenesis takes millions of lives of peoples and the unavailability of appropriate therapeutic strategy makes it much more severe. Toll-like receptors (TLRs) are the crucial mediators and regulators of host immunity. The role of several TLRs in immunomodulation of host by SARS-CoV-2 is recently demonstrated. However, the functionality of human intracellular TLRs including TLR3,7,8 and 9 is still being untested for sensing of viral RNA. This study is hoped to rationalize the comparative binding and sensing of SARS-CoV-2 mRNA towards the intracellular TLRs, considering the solvent-based force-fields operational in the cytosolic aqueous microenvironment that predominantly drive these reactions. Our in-silico study on the binding of all mRNAs with the intracellular TLRs shown that the mRNA of NSP10, S2, and E proteins of SARS-CoV-2 are potent enough to bind with TLR3, TLR9, and TLR7 and trigger downstream cascade reactions, and may be used as an option for validation of therapeutic option and immunomodulation against COVID-19.


Genes ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1677
Author(s):  
Shuqian Wang ◽  
Jing Jin ◽  
Jing Chen ◽  
Weiyang Lou

Growing evidences have showed that mucins (MUCs) are linked to occurrence and progression of human cancers. However, a comprehensive study regarding the expression, diagnosis, prognosis and mechanism of MUCs in breast cancer remains absent. Methods: A series of in silico analyses were employed in this study. Results: After performing comprehensive analysis for MUCs, MUC14 was identified as the most potential regulator in breast cancer, with downregulated expression in both mRNA and protein levels and significant diagnostic and prognostic values in breast cancer. Mechanistic exploration revealed that a potential ncRNA-mRNA axis, involving LINC01128/LINC01140/SGMS1-AS1/LINC00667-miR-137/miR-429-BCL2, might be partially responsible for MUC14′s functions in breast cancer. Conclusions: Collectively, our study elucidated a key role of MUC14 in breast cancer and also provided some clues for explanation of the molecular action mechanism of MUC14 in breast cancer.


Author(s):  
Ю.И. Кирова ◽  
Э.Л. Германова

Митохондриогенез и ангиогенез являются ключевыми нейропротекторными механизмами, повышающими устойчивость нервной ткани к условиям гипоксии/ишемии. В настоящее время фармакологическая индукция биогенеза митохондрий является одним из наиболее перспективных и активно разрабатываемых подходов к коррекции ишемических и постишемических нарушений, нейродегенеративных заболеваний и кардиопатий. Выявление факта стимуляции митохондриогенеза эталонными нейропротекторными препаратами позволит существенно расширить представление об их терапевтическом потенциале и принципах применения. Цель исследования - изучение влияния нейропротекторного сукцинатсодержащего препарата мексидол на экспрессию каталитических субъединиц дыхательных ферментов митохондрий, АТФ-синтазы и фактора роста эндотелия сосудов в коре головного мозга крыс с врожденными различиями в устойчивости к дефициту кислорода. Методика. Исследование выполнено на белых беспородных крысах-самцах. Инъекции мексидола (40 мг/кг, внутрибрюшинно) выполняли ежедневно на протяжении 20 сут. Уровень экспрессии каталитических субъединиц дыхательных ферментов митохондрий и АТФ-синтазы, фактора роста эндотелия сосудов и сукцинатного рецептора в ткани коры головного мозга оценивали методом иммуноблоттинга. Общую резистентность организма к острой гипоксии тестировали в гипобарической камере проточного типа при разрежении атмосферы, соответствующем 190 мм рт. ст. (3% О). Результаты. В ходе курса применения мексидола происходило увеличение уровня каталитических субъединиц дыхательных ферментов митохондрий (NDUFV2, SDHA, cyt b, COX1), АТФ-синтазы (ATP5A), фактора роста эндотелия сосудов (VEGF) и сукцинатного рецептора (SUCNR1), особенно выраженное у неустойчивых к гипоксии особей. Заключение. Впервые показана вовлеченность сукцинатсодержащего препарата мексидол в механизмы индукции ферментов энергопродуцирующей системы митохондрий коры головного мозга, что существенно расширяет сложившиеся представления о механизмах его энерготропного действия. Mitochondriogenesis and angiogenesis are crucial neuroprotective mechanisms that increase the resistance of nervous tissue to hypoxia/ischemia conditions. Currently, pharmacological induction of mitochondrial biogenesis is one of the most promising and actively developed approaches for the correction of ischemic and post-ischemic disorders, neurodegenerative diseases and cardiopathies. Revealing the fact of stimulation of mitochondriogenesis with standard neuroprotective drugs will significantly expand the understanding of their therapeutic potential and principles of application. The aim of the research was to study the effect of the neuroprotective succinate-containing drug mexidol on the expression of catalytic subunits of the respiratory enzymes of mitochondria, ATP-synthase and vascular endothelial growth factor in the cerebral cortex of rats with inborn differences in resistance to oxygen deficiency. Methods. The study was carried out on white mongrel rats-males injections of mexidol (40 mg/kg, intraperitoneally) were performed daily for 20 days. The expression level of the catalytic subunits of the respiratory enzymes of mitochondria and ATP-synthase, vascular endothelial growth factor and succinate receptor in the tissue of the cerebral cortex was assessed by immunoblotting. The total resistance of the organism to acute hypoxia was tested in a hypobaric chamber with an atmosphere underpressure corresponding to 190 mm Hg (3% O). Results. During the injection course of mexidol, there was an increase in the level of catalytic subunits of the respiratory enzymes of mitochondria (NDUFV2, SDHA, cyt b, COX1), ATP-synthase (ATP5A), vascular endothelial growth factor (VEGF) and succinate receptor (SUCNR1), especially pronounced in rats with low-resistance to hypoxia. Conclusion. The study revealed for the first time the involvement of the succinate-containing drug mexidol in the mechanisms of induction of enzymes of the energy-producing system of the mitochondria of the cerebral cortex, which significantly expands the existing ideas about the mechanisms of its energy-tropic action.


2015 ◽  
Vol 15 (3) ◽  
pp. 253-269 ◽  
Author(s):  
L. Scotti ◽  
H. Ishiki ◽  
F.J.B. Mendonca ◽  
M.S. Silva ◽  
M.T. Scotti

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