The cytochrome chain of mitochondria exhibits variable H+/e− stoichiometry

AbstractA study is presented of the ←H+/e− stoichiometry for H+ pumping by the cytochrome chain in isolated rat liver mitochondria under level-flow and steady-state conditions. It is shown that the ←H+/e− stoichiometry for the cytochrome chain varies under the influence of the flow rate and transmembrane ΔμH+. The rate-dependence is shown to be associated with cytochrome c oxidase, whose ←H+/e− ratio varies from 0 to 1, whilst the ←H+/c− ratio for the span covered by cytochrome c reductase is invariably 2

Variations in some of the body fluid hormone levels currently used for endocrine monitoring during the third trimester of pregnancy

Peer Reviewe

Effect of chicken bone extracts on metabolic and mitochondrial functions of K562 cell line

Background: Tetracyclines’ use in intensive animal farming has raised some concerns regarding the biosafety for humans. Increasing evidences have revealed the presence of these drugs in processed animal by-products, such as bone, throughout the food chain. A potential off-target of tetracyclines is the bacterial-like mitochondrial translational machinery, thereby causing proteostatic alterations in mitochondrial DNA-encoded components of the oxidative phosphorylation system. Methods: The Seahorse methodology, confocal microscopy imaging of mitochondrial potential and reactive oxygen species, and q-RT-PCR analysis of the expression of genes involved in mitochondrial biogenesis and mitophagy were carried out on human lymphoblast derived K562 cell line challenged with bone powder derived from chicken treated with or without oxytetracycline and pure oxytetracycline. Results: A complex dose-dependent profile was attained with a low dosage of bone powder extracts causing a metabolic adaptation hallmarked by stimulation of the mitochondrial respiration and enhanced expression of mitochondriogenic factors in particular in cells challenged with oxytetracycline-free bone extract. Conversely, a higher dosage of bone powder extracts, regardless of their source, caused a progressive inhibition of mitochondrial respiration and glycolysis, ultimately leading to cell death. No significant effects of the pure oxytetracycline were observed. Conclusion: Bone powder, regardless of chicken treatment, contains and releases factors/chemicals responsible for the observed effects on energy metabolism. Quantitative differential effects appear to depend on biochemical alterations in the bone matrix caused by antibiotics rather than antibiotics themselves

High mobilization of CD133+/CD34+ cells expressing HIF-1α and SDF-1α in septic abdominal surgical patients

Background: The control of endothelial progenitor cells (CD133+/CD34+ EPCs) migrating from bone marrow to peripheral blood is not completely understood. Emerging evidence suggests that stromal cell-derived factor-1α (SDF-1α) mediates egression of EPCs from bone marrow, while the hypoxia inducible factor (HIF) transcriptional system regulates SDF-1α expression. Our study aimed to investigate the time course of circulating CD133+/CD34+ EPCs and its correlation with the expression of HIF-1α protein and SDF-1α in postoperative laparoscopic abdominal septic patients. Methods: Postoperative patients were divided in control (C group) and septic group (S group) operated immediately after the diagnosis of sepsis/septic shock. Blood samples were collected at baseline (0), 1, 3 and 7 postoperative days for CD133+/CD34+ EPCs count expressing or not the HIF-1α and SDF-1α analysis. Results: Thirty-two patients in S group and 39 in C group were analyzed. In C group CD133+/CD34+ EPCs count remained stable throughout the study period, increasing on day 7 (173 [0-421] /μl vs baseline: P = 0.04; vs day 1: P = 0.002). In S group CD133+/CD34+ EPCs count levels were higher on day 3 (vs day 1: P = 0.006 and day 7: P = 0.026). HIF-1α expressing CD133+/CD34+ EPCs count decreased on day 1 as compared with the other days in C group (day 0 vs 1: P = 0.003, days 3 and 7 vs 1: P = 0.008), while it was 321 [0-1418] /μl on day 3 (vs day 1; P = 0.004), and 400 [0-587] /μl on day 7 in S group. SDF-1α levels were higher not only on baseline but also on postoperative day 1 in S vs C group (219 [124-337] pg/ml vs 35 [27-325] pg/ml, respectively; P = 0.01). Conclusion: Our results indicate that sepsis in abdominal laparoscopic patients might constitute an additional trigger of the EPCs mobilization as compared with non-septic surgical patients. A larger mobilization of CD133+/CD34+ EPCs, preceded by enhanced plasmatic SDF-1α, occurs in septic surgical patients regardless of HIF-1α expression therein. Trial registration: ClinicalTrials.gov no. NCT02589535. Registered 28 October 2015

Unveiling metabolic vulnerability and plasticity of human osteosarcoma stem and differentiated cells to improve cancer therapy

Defining the metabolic phenotypes of cancer-initiating cells or cancer stem cells and of their differentiated counterparts might provide fundamental knowledge for improving or developing more effective therapies. In this context we extensively characterized the metabolic profiles of two osteosarcoma-derived cell lines, the 3AB-OS cancer stem cells and the parental MG-63 cells. To this aim Seahorse methodology-based metabolic flux analysis under a variety of conditions complemented with real time monitoring of cell growth by impedentiometric technique and confocal imaging were carried out. The results attained by selective substrate deprivation or metabolic pathway inhibition clearly show reliance of 3AB-OS on glycolysis and of MG-63 on glutamine oxidation. Treatment of the osteosarcoma cell lines with cisplatin resulted in additive inhibitory effects in MG-63 cells depleted of glutamine whereas it antagonized under selective withdrawal of glucose in 3AB-OS cells thereby manifesting a paradoxical pro-survival, cell-cycle arrest in S phase and antioxidant outcome. All together the results of this study highlight that the efficacy of specific metabolite starvation combined with chemotherapeutic drugs depends on the cancer compartment and suggest cautions in using it as a generalizable curative strategy

Targeting Endoplasmic Reticulum and/or Mitochondrial Ca2+ Fluxes as Therapeutic Strategy for HCV Infection.

Chronic hepatitis C is characterized by metabolic disorders and by a microenvironment in the liver dominated by oxidative stress, inflammation and regeneration processes that can in the long term lead to liver cirrhosis and hepatocellular carcinoma. Several lines of evidence suggest that mitochondrial dysfunctions play a central role in these processes. However, how these dysfunctions are induced by the virus and whether they play a role in disease progression and neoplastic transformation remains to be determined. Most javax.xml.bind.JAXBElement@5b15fc8d studies performed so far have shown that several of the hepatitis C virus (HCV) proteins also localize to mitochondria, but the consequences of these interactions on mitochondrial functions remain contradictory and need to be confirmed in the context of productively replicating virus and physiologically relevant javax.xml.bind.JAXBElement@5e13485c and javax.xml.bind.JAXBElement@73aee95e model systems. In the past decade we have been proposing a temporal sequence of events in the HCV-infected cell whereby the primary alteration is localized at the mitochondria-associated ER membranes and causes release of Ca javax.xml.bind.JAXBElement@476155bf from the ER, followed by uptake into mitochondria. This ensues successive mitochondrial dysfunction leading to the generation of reactive oxygen and nitrogen species and a progressive metabolic adaptive response consisting in decreased oxidative phosphorylation and enhanced aerobic glycolysis and lipogenesis. Here we resume the major results provided by our group in the context of HCV-mediated alterations of the cellular inter-compartmental calcium flux homeostasis and present new evidence suggesting targeting of ER and/or mitochondrial calcium transporters as a novel therapeutic strategy

Discovery of the INTEGRAL X/Gamma-ray transient IGR J00291+5934: a Comptonised accreting ms pulsar ?

We report the discovery of a high-energy transient with the IBIS/ISGRI detector on board the INTEGRAL observatory. The source, namely IGR J00291+5934, was first detected on 2nd December 2004 in the routine monitoring of the IBIS/ISGRI 20--60 keV images. The observations were conducted during Galactic Plane Scans, which are a key part of the INTEGRAL Core Programme observations. After verifying the basic source behaviour, the discovery was announced on 3rd December. The transient shows a hard Comptonised spectrum, with peak energy release at about 20 keV and a total luminosity of ~ 0.9E36 erg/s in the 5--100 keV range, assuming a distance of 3 kpc. Following the INTEGRAL announcement of the discovery of IGR J00291+5934, a number of observations were made by other instruments. We summarise the results of those observations and, together with the INTEGRAL data, identifiy IGR J00291+5934 as the 6th member of a class of accreting X-ray millisecond pulsars.Comment: Accepted for publication as an A&A Letter 24/01/2005. 5 pages, 2 figure