The historical anthropogenic impact on sediments from the Basque Mud Patch (southern Bay of Biscay) is explored using a multidisciplinary approach including the analysis of natural (210Pb) and ...artificial (137Cs, 239/240Pu) radiotracers, major elements (Al, Mn), metals (Zn, Pb, Cu, Cr), Pb isotopic ratios, and foraminiferal and pollen contents. The study of three short cores (19–46 cm), despite being hindered by the effects of biomixing, allow the calculation of a sedimentation rate of 1 ± 0.1 mm yr−1. Distribution with depth of Al-normalised concentrations of metals reflects an increasing trend since 1880 CE, related to the industrialization of the Basque coastal area. According to the Sediment Quality Guidelines applied, contents of Zn and Pb appear as a potential cause of concern, given that they exceed the values from which adverse biological effects can be occasionally expected. However, foraminiferal assemblages do not show recognizable changes along the cores following increasing trace metal concentrations. Finally, pollen results reveal an increasing trend of coniferous taxa and a parallel reduction of authochthonous Deciduous Quercus, probably as a consequence of reforestation works. Data obtained confirm that effects of coastal anthropogenic activities extend to the adjacent shelf, where muddy deposits are likely to act as a trap for contaminants.
Pollen analyses supported by fifteen AMS 14C dates from Fuente de la Leche (1382 m) and Fuente del Pino Blanco (1343 m) peat sequences, in the Gredos range (central Spain), are used to reconstruct ...the late Holocene vegetation history in this mountain region. These results are compared with other sequences from the Spanish Central System in order to better understand the past dynamics of the main forest constituents and to provide a critical view of the dialectic between conifers and deciduous forests. The vegetation record at Fuente de la Leche starts at 3000 cal yr BP, with the occurrence of rather closed forests composed of Pinus sylvestris and Betula. Pinus sylvestris was the dominant pollen taxa for almost the entire period. However, during the last 850 years, Pinus sylvestris forests were progressively replaced by Quercus pyrenaica woodlands and grasslands, as a result of a high pastoral pressure, until forming mixed woodlands ∼400 years ago. The interpretation of Fuente del Pino Blanco record is that dramatic changes started about 265 years ago. Prior to this date, an open canopy woodland included species (Alnus glutinosa, Quercus pyrenaica) whose distributions no longer exist in the studied area. We suggest that the increase in agricultural (rye and other cereals) and livestock activities forced a change in the role of fire in the supramediterranean belt of the Gredos range, thus Pyrenean oak canopy was consumed by fires, providing openings for Pinus pinaster and broom communities better adapted to fire.
Mitochondrial respiratory chain (MRC) complexes I, III, and IV associate into a variety of supramolecular structures known as supercomplexes and respirasomes. While COX7A2L was originally described ...as a supercomplex-specific factor responsible for the dynamic association of complex IV into these structures to adapt MRC function to metabolic variations, this role has been disputed. Here, we further examine the functional significance of COX7A2L in the structural organization of the mammalian respiratory chain. As in the mouse, human COX7A2L binds primarily to free mitochondrial complex III and, to a minor extent, to complex IV to specifically promote the stabilization of the III2+IV supercomplex without affecting respirasome formation. Furthermore, COX7A2L does not affect the biogenesis, stabilization, and function of the individual oxidative phosphorylation complexes. These data show that independent regulatory mechanisms for the biogenesis and turnover of different MRC supercomplex structures co-exist.
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•COX7A2L preferentially interacts with respiratory chain complex III•COX7A2L is essential to stabilize the III2+IV supercomplex•COX7A2L is not necessary for biogenesis or maintenance of the respirasome•Biogenesis of the III2+IV supercomplex is not necessary for respirasome formation
Previous studies highlight different roles for COX7A2L in the structural organization of the mitochondrial respiratory chain. Pérez-Pérez et al. find that mammalian COX7A2L preferentially associates with complex III to stabilize supercomplex III2+IV in a respirasome-independent manner, indicating coexistence of independent regulatory mechanisms for the biogenesis and turnover of these structures.
Our goal was to analyze postmortem tissues of an adult patient with late-onset thymidine kinase 2 (TK2) deficiency who died of respiratory failure. Compared with control tissues, we found a low mtDNA ...content in the patient’s skeletal muscle, liver, kidney, small intestine, and particularly in the diaphragm, whereas heart and brain tissue showed normal mtDNA levels. mtDNA deletions were present in skeletal muscle and diaphragm. All tissues showed a low content of OXPHOS subunits, and this was especially evident in diaphragm, which also exhibited an abnormal protein profile, expression of non-muscular β-actin and loss of GAPDH and α-actin. MALDI-TOF/TOF mass spectrometry analysis demonstrated the loss of the enzyme fructose-bisphosphate aldolase, and enrichment for serum albumin in the patient’s diaphragm tissue. The TK2-deficient patient’s diaphragm showed a more profound loss of OXPHOS proteins, with lower levels of catalase, peroxiredoxin 6, cytosolic superoxide dismutase, p62 and the catalytic subunits of proteasome than diaphragms of ventilated controls. Strong overexpression of TK1 was observed in all tissues of the patient with diaphragm showing the highest levels. TK2 deficiency induces a more profound dysfunction of the diaphragm than of other tissues, which manifests as loss of OXPHOS and glycolytic proteins, sarcomeric components, antioxidants and overactivation of the TK1 salvage pathway that is not attributed to mechanical ventilation.
Mitochondrial respiratory chain (MRC) complexes I, III and IV associate into a variety of supramolecular structures known as supercomplexes and respirasomes. While COX7A2L was originally described as ...a supercomplex-specific factor responsible for the dynamic association of complex IV into these structures to adapt MRC function to metabolic variations, this role has been disputed. Here we further examine the functional significance of COX7A2L in the structural organization of the mammalian respiratory chain. As in the mouse, human COX7A2L binds primarily to free mitochondrial complex III and to a minor extent to complex IV to specifically promote the stabilization of the III2+IV supercomplex without affecting respirasome formation. Furthermore, COX7A2L does not affect the biogenesis, stabilization and function of the individual OXPHOS complexes. These data show that independent regulatory mechanisms for the biogenesis and turnover of different MRC supercomplex structures co-exist.
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1COX7A2L preferentially interacts with respiratory chain complex III2COX7A2L is essential to stabilize the III2+IV supercomplex3COX7A2L is not necessary for biogenesis or maintenance of the respirasome4Biogenesis of the III2+IV supercomplex is not necessary for respirasome formation
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