RESUMEN
Intrinsic apoptosis as a modality of regulated cell death is intimately linked to permeabilization of the outer mitochondrial membrane and subsequent release of the protein cytochrome c into the cytosol, where it can participate in caspase activation via apoptosome formation. Interestingly, cytochrome c release is an ancient feature of regulated cell death even in unicellular eukaryotes that do not contain an apoptosome. Therefore, it was speculated that cytochrome c release might have an additional, more fundamental role for cell death signalling, because its absence from mitochondria disrupts oxidative phosphorylation. Here, we permanently anchored cytochrome c with a transmembrane segment to the inner mitochondrial membrane of the yeast Saccharomyces cerevisiae, thereby inhibiting its release from mitochondria during regulated cell death. This cytochrome c retains respiratory growth and correct assembly of mitochondrial respiratory chain supercomplexes. However, membrane anchoring leads to a sensitisation to acetic acid-induced cell death and increased oxidative stress, a compensatory elevation of cellular oxygen-consumption in aged cells and a decreased chronological lifespan. We therefore conclude that loss of cytochrome c from mitochondria during regulated cell death and the subsequent disruption of oxidative phosphorylation is not required for efficient execution of cell death in yeast, and that mobility of cytochrome c within the mitochondrial intermembrane space confers a fitness advantage that overcomes a potential role in regulated cell death signalling in the absence of an apoptosome.
Asunto(s)
Muerte Celular/fisiología , Citocromos c/metabolismo , Mitocondrias/metabolismo , Levaduras/patogenicidad , HumanosRESUMEN
Mitochondria have a characteristic ultrastructure with invaginations of the inner membrane called cristae that contain the protein complexes of the oxidative phosphorylation system. How this particular morphology of the respiratory membrane impacts energy conversion is currently unknown. One proposed role of cristae formation is to facilitate the establishment of local proton gradients to fuel ATP synthesis. Here, we determined the local pH values at defined sublocations within mitochondria of respiring yeast cells by fusing a pH-sensitive GFP to proteins residing in different mitochondrial subcompartments. Only a small proton gradient was detected over the inner membrane in wild type or cristae-lacking cells. Conversely, the obtained pH values did barely permit ATP synthesis in a reconstituted system containing purified yeast F1F0 ATP synthase, although, thermodynamically, a sufficiently high driving force was applied. At higher driving forces, where robust ATP synthesis was observed, a P-side pH value of 6 increased the ATP synthesis rate 3-fold compared to pH 7. In contrast, when ATP synthase was coreconstituted with an active proton-translocating cytochrome oxidase, ATP synthesis readily occurred at the measured, physiological pH values. Our study thus reveals that the morphology of the inner membrane does not influence the subcompartmental pH values and is not necessary for robust oxidative phosphorylation in mitochondria. Instead, it is likely that the dense packing of the oxidative phosphorylation complexes in the cristae membranes assists kinetic coupling between proton pumping and ATP synthesis.
Asunto(s)
Adenosina Trifosfato/biosíntesis , Membranas Mitocondriales/metabolismo , ATPasas de Translocación de Protón Mitocondriales/metabolismo , Protones , Transporte de Electrón , Concentración de Iones de Hidrógeno , Cinética , Mitocondrias/química , Mitocondrias/genética , Mitocondrias/metabolismo , Mitocondrias/ultraestructura , Membranas Mitocondriales/química , Membranas Mitocondriales/enzimología , ATPasas de Translocación de Protón Mitocondriales/genética , Fosforilación Oxidativa , Proteolípidos/metabolismo , Bombas de Protones/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismoRESUMEN
STUDY OBJECTIVE: We detected mesh erosion and serious postoperative complications in 3 women after performing laparoscopic promontofixation (LPF) using glue for mesh fixation. Glue, largely used in hernia surgery repair, is proposed by some gynecologic surgeons because it saves time and is easier to use than traditional sutures. We report 3 cases of postoperative complications after LPF in which glue had been used and provide research in the published literature about the use of glue in LPF. METHODS: A research of glue use in gynecology mesh fixation was performed through PubMed on October 2016. The search was done using the Medical Subject Heading terms "POP" & "Laparoscopy" & "surgical Mesh" and the word either "glue" or "adhesive. Only 2 articles were found: Willecocq et al [1] and Estrade et al [2]. Neither study focused on postoperative complications. In this publication, we accurately edited video surgeries with an instructive purpose. SETTING: University Hospital of Clermont-Ferrand, France. CASE REPORTS: Patient A, a 65-year-old woman, complained of pelvic pain and vaginal discharge 1 month after LPF (polypropylene mesh and glue had been used). Wall mesh exposure and purulent discharge were noted. She received antibiotics and underwent mesh ablation surgery; debris of the glue was easily identified. Patient B, a 65-year-old lady with previous hysterectomy consulted for a bulging feeling in her vagina (classification: cystocele +2; rectocele +3 stage). An LPF was performed using polypropylene soft nonabsorbable mesh and glue. One month later, an apical defect of vaginal epithelialization was detected; she received long estrogenic local treatment but had to undergo surgery when presenting malodorous discharge and mesh exposure. The exposed mesh was removed, and pieces of glue were identified, having avoided mesh attachment. Patient C had a previous abdominal hysterectomy and promontofixation using a polyester mesh with glue. She consulted to us for vaginal mesh erosion covered with purulent discharge 3.5 years after LPF in another center. At the surgery, 1 cm of the prosthesis was identified in the vagina, dissected, and sutured. One year later, she consulted for dyspareunia and purulent discharge; vaginal rigid mesh exposure with an epithelization defect and inflammatory signs was seen. During laparoscopy, prosthetic exposition and glue debris on the prosthesis were identified. DISCUSSION: In all 3 cases, debris of glue were identified in the no integrated mesh area. The suggested reasons of exposure can be the excessive amount of surgical glue applied. Moreover, a large amount of glue may be impairing tissue ingrowth through the mesh pores, causing low fibrosis and poor tissue integration [3]. CONCLUSION: Glue seems to prevent fibrosis from occurring. Its use in pelvic organ prolapse laparoscopic mesh fixation should be done with caution. No prospective studies reporting long-term comorbidities and results have been published.
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Procedimientos Quirúrgicos Ginecológicos , Prolapso de Órgano Pélvico/cirugía , Complicaciones Posoperatorias/etiología , Mallas Quirúrgicas/efectos adversos , Adhesivos Tisulares/efectos adversos , Adhesivos , Anciano , Cistocele , Femenino , Humanos , Histerectomía , Laparoscopía , Polipropilenos , VaginaRESUMEN
The European corn borer (ECB) is an important pest of maize in the northern hemisphere, but no reliable techniques exist for monitoring females during their reproductive period. In this study, we aimed to identify host-plant volatiles used by gravid Z-strain females in search for oviposition sites. Headspace of maize plants, to which gravid females orientated in a wind tunnel, was collected, and physiologically-active components were identified by using gas chromatography (GC) coupled with electroantennographic detection followed by GC-mass spectrometry. The antennae of female moths consistently responded to two maize volatiles, nonanal and decanal. Although these compounds are individually not characteristic for maize, a synthetic mix in a ratio found in maize headspace, 1:2.4 at 1 µg µl(-1) induced source contact and landing responses similar to maize plants in the wind tunnel. However, fewer females took flight in response to the mix, and those that took flight did so with an increased latency. To our knowledge, this is the first blend of host-plant volatiles that has been found to be physiologically active and to be able to induce attraction of gravid ECB females under laboratory conditions. Future tests will evaluate the attractiveness of the blend to the E-strain of ECB, the attractiveness of the blend in the field, and its potential in monitoring ECB populations.
Asunto(s)
Antenas de Artrópodos/fisiología , Mariposas Nocturnas/fisiología , Oviposición , Compuestos Orgánicos Volátiles/metabolismo , Zea mays/química , Animales , Fenómenos Electrofisiológicos , Femenino , Cromatografía de Gases y Espectrometría de MasasRESUMEN
Maintenance, repair, and renewal of the epidermis are thought to depend on a pool of dedicated epidermal stem cells (EpiSCs). Like for many somatic tissues, isolation of a nearly pure population of stem cells is a primary goal in cutaneous biology. We used a quantitative transplantation assay, using injection of keratinocytes into subcutis combined with limiting dilution analysis, to assess the long-term repopulating ability of putative murine EpiSC populations. Putative EpiSC populations were isolated by FACS sorting. The CD133(+) population and the subpopulation of CD133(+) cells that exhibits high mitochondrial membrane potential (DΨm(hi)) were enriched for long-term repopulating EpiSCs versus unfractionated cells (3.9- and 5.2-fold, respectively). Evidence for self-renewal capacity was obtained by serial transplantation of long-term epidermal repopulating units derived from CD133(+) and CD133(+)ΔΨm(hi) keratinocytes. CD133(+) keratinocytes were multipotent and produced significantly more hair follicles than CD133(-) cells. CD133(+) cells were a subset of the previously described integrin α6(+)CD34(+) bulge cell population, and 28.9±8.6% were label-retaining cells. Thus, murine keratinocytes within the CD133(+) and CD133(+)ΔΨm(hi) populations contain EpiSCs that regenerate the epidermis for the long term, are self-renewing, multipotent, and label-retaining cells.
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Antígenos CD/metabolismo , Células Epidérmicas , Epidermis/fisiología , Glicoproteínas/metabolismo , Queratinocitos/citología , Células Madre Multipotentes/citología , Péptidos/metabolismo , Antígeno AC133 , Animales , Biomarcadores/metabolismo , Diferenciación Celular/fisiología , Proliferación Celular , Fibroblastos/citología , Fibroblastos/fisiología , Citometría de Flujo , Proteínas Fluorescentes Verdes/genética , Integrina alfa6/metabolismo , Queratinocitos/fisiología , Potenciales de la Membrana/fisiología , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos NOD , Ratones SCID , Ratones Transgénicos , Células Madre Multipotentes/fisiología , Regeneración/fisiología , Trasplante de Piel , Trasplante HomólogoRESUMEN
ABCB6, a member of the adenosine triphosphate-binding cassette (ABC) transporter family, has been proposed to be responsible for the mitochondrial uptake of porphyrins. Here we show that ABCB6 is a glycoprotein present in the membrane of mature erythrocytes and in exosomes released from reticulocytes during the final steps of erythroid maturation. Consistent with its presence in exosomes, endogenous ABCB6 is localized to the endo/lysosomal compartment, and is absent from the mitochondria of cells. Knock-down studies demonstrate that ABCB6 function is not required for de novo heme biosynthesis in differentiating K562 cells, excluding this ABC transporter as a key regulator of porphyrin synthesis. We confirm the mitochondrial localization of ABCB7, ABCB8 and ABCB10, suggesting that only three ABC transporters should be classified as mitochondrial proteins. Taken together, our results challenge the current paradigm linking the expression and function of ABCB6 to mitochondria.
Asunto(s)
Transportadoras de Casetes de Unión a ATP/análisis , Membrana Eritrocítica/metabolismo , Lisosomas/metabolismo , Proteínas Mitocondriales/análisis , Transportadoras de Casetes de Unión a ATP/genética , Transportadoras de Casetes de Unión a ATP/metabolismo , Diferenciación Celular , Eritrocitos/citología , Eritrocitos/metabolismo , Células Eritroides/citología , Células Eritroides/metabolismo , Exosomas/metabolismo , Expresión Génica , Técnicas de Silenciamiento del Gen , Hemoglobinas/metabolismo , Humanos , Células K562 , Mitocondrias/metabolismo , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismoRESUMEN
Patient (or person) master index (PMI) data quality activities in public, acute healthcare facilities in the state of Victoria, Australia were evaluated in terms of health information management-information technology best practice including data standards and practice guidelines. The findings indicate that, whilst data quality and linkage activities are undertaken, many are limited in scope or effectiveness. In view of published evidence that: (i) duplicate patient files pose significant risks by reducing information available for clinical decision-making; and (ii) quality and clinical risk management require, as a measurable outcome, continuous monitoring of duplicate files, improvements to PMI data quality practices are recommended.