The “glacial” sapropel S6 (172 ka; MIS 6): A multiproxy approach to solve a Mediterranean “cold case”

Sequences of dark, organic-rich sediment layers (sapropels) exist throughout the Neogene of the Mediterranean Sea sedimentary record. While the mechanisms behind their cyclical deposition are not entirely understood, they have been found to correspond with precession minima (Northern Hemisphere [NH] insolation maxima). This causes NH summer monsoon to shift northward and intensify, which increases precipitation over North Africa and alters Mediterranean freshwater budget, leading to restricted bottom-water ventilation and anoxia. Most Mediterranean sapropels were deposited during interglacial periods, but sapropel S6 formed during the penultimate glaciation of Marine Isotopic Stage 6 (MIS 6; 190–130 ka), during which the Eurasian ice sheet extended to its maximum size of the Quaternary. Eurasian ice-sheet melting may have provided an additional input of freshwater to the Mediterranean during S6 deposition. To test this hypothesis, we present a multiproxy paleoecological (planktic foraminifera, calcareous nannofossils, pollen, dinocysts) and geochemical (foraminiferal δ18O) study of S6 from the Ionian Sea. We confirm that S6 deposition resulted from an interaction of two different mechanisms of freshwater input to the Mediterranean, in which: (1) local ice-sheet meltwater discharge preconditioned the basin for stratification; and (2) increased monsoon activity over North Africa caused intense precipitation and river runoff that exacerbated water-column stratification. Our results provide new evidence for the prevalence of mild/temperate and humid conditions during S6 deposition, dispelling the notion that this “glacial” sapropel formed under cold and dry conditions and we document signals of warm (interstadial) and cold (stadial) conditions within S6 in the eastern Mediterranean basin

The “glacial” sapropel S6 (172 ka; MIS 6): A multiproxy approach to solve a Mediterranean “cold case”

Sequences of dark, organic-rich sediment layers (sapropels) exist throughout the Neogene of the Mediterranean Sea sedimentary record. While the mechanisms behind their cyclical deposition are not entirely understood, they have been found to correspond with precession minima (Northern Hemisphere [NH] insolation maxima). This causes NH summer monsoon to shift northward and intensify, which increases precipitation over North Africa and alters Mediterranean freshwater budget, leading to restricted bottom-water ventilation and anoxia. Most Mediterranean sapropels were deposited during interglacial periods, but sapropel S6 formed during the penultimate glaciation of Marine Isotopic Stage 6 (MIS 6; 190–130 ka), during which the Eurasian ice sheet extended to its maximum size of the Quaternary. Eurasian ice-sheet melting may have provided an additional input of freshwater to the Mediterranean during S6 deposition. To test this hypothesis, we present a multiproxy paleoecological (planktic foraminifera, calcareous nannofossils, pollen, dinocysts) and geochemical (foraminiferal δ18O) study of S6 from the Ionian Sea. We confirm that S6 deposition resulted from an interaction of two different mechanisms of freshwater input to the Mediterranean, in which: (1) local ice-sheet meltwater discharge preconditioned the basin for stratification; and (2) increased monsoon activity over North Africa caused intense precipitation and river runoff that exacerbated water-column stratification. Our results provide new evidence for the prevalence of mild/temperate and humid conditions during S6 deposition, dispelling the notion that this “glacial” sapropel formed under cold and dry conditions and we document signals of warm (interstadial) and cold (stadial) conditions within S6 in the eastern Mediterranean basi

A novel splicing mutation in the ALB gene causing analbuminaemia in a Portuguese woman

info:eu-repo/semantics/publishedVersio

Sleep‐Disordered Breathing and 24‐Hour Ambulatory Blood Pressure Monitoring in Renal Transplant Patients: Longitudinal Study

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Diagnosis, Phenotype, and Molecular Genetics of Congenital Analbuminemia

Congenital analbuminemia (CAA) is an inherited, autosomal recessive disorder with an incidence of 1:1,000,000 live birth. Affected individuals have a strongly decreased concentration, or complete absence, of serum albumin. The trait is usually detected by serum protein electrophoresis and immunochemistry techniques. However, due to the existence of other conditions in which the albumin concentrations are very low or null, analysis of the albumin (ALB) gene is necessary for the molecular diagnosis. CAA can lead to serious consequences in the prenatal period, because it can cause miscarriages and preterm birth, which often is due to oligohydramnios and placental abnormalities. Neonatally and in early childhood the trait is a risk factor that can lead to death, mainly from fluid retention and infections in the lower respiratory tract. By contrast, CAA is better tolerated in adulthood. Clinically, in addition to the low level of albumin, the patients almost always have hyperlipidemia, but they usually also have mild oedema, reduced blood pressure and fatigue. The fairly mild symptoms in adulthood are due to compensatory increment of other plasma proteins. The condition is rare; clinically, only about 90 cases have been detected worldwide. Among these, 53 have been studied by sequence analysis of the ALB gene, allowing the identification of 27 different loss of function (LoF) pathogenic variants. These include a variant in the start codon, frame-shift/insertions, frame-shift/deletions, nonsense variants, and variants affecting splicing. Most are unique, peculiar for each affected family, but one, a frame-shift deletion called Kayseri, has been found to cause about one third of the known cases allowing to presume a founder effect. This review provides an overview of the literature about CAA, about supportive and additional physiological and pharmacological information obtained from albumin-deficient mouse and rat models and a complete and up-to-date dataset of the pathogenic variants identified in the ALB gene

A Retrotransposon Insertion in the 5' Regulatory Domain of Ptf1a Results in Ectopic Gene Expression and Multiple Congenital Defects in Danforth’s Short Tail Mouse

Danforth's short tail mutant (Sd) mouse, first described in 1930, is a classic spontaneous mutant exhibiting defects of the axial skeleton, hindgut, and urogenital system. We used meiotic mapping in 1,497 segregants to localize the mutation to a 42.8-kb intergenic segment on chromosome 2. Resequencing of this region identified an 8.5-kb early retrotransposon (ETn) insertion within the highly conserved regulatory sequences upstream of Pancreas Specific Transcription Factor, 1a (Ptf1a). This mutation resulted in up to tenfold increased expression of Ptf1a as compared to wild-type embryos at E9.5 but no detectable changes in the expression levels of other neighboring genes. At E9.5, Sd mutants exhibit ectopic Ptf1a expression in embryonic progenitors of every organ that will manifest a developmental defect: the notochord, the hindgut, and the mesonephric ducts. Moreover, at E 8.5, Sd mutant mice exhibit ectopic Ptf1a expression in the lateral plate mesoderm, tail bud mesenchyme, and in the notochord, preceding the onset of visible defects such as notochord degeneration. The Sd heterozygote phenotype was not ameliorated by Ptf1a haploinsufficiency, further suggesting that the developmental defects result from ectopic expression of Ptf1a. These data identify disruption of the spatio-temporal pattern of Ptf1a expression as the unifying mechanism underlying the multiple congenital defects in Danforth's short tail mouse. This striking example of an enhancer mutation resulting in profound developmental defects suggests that disruption of conserved regulatory elements may also contribute to human malformation syndromes

Urinary secretion and extracellular aggregation of mutant uromodulin isoforms.

Uromodulin is exclusively expressed in the thick ascending limb and is the most abundant protein secreted in urine where it is found in high-molecular-weight polymers. Its biological functions are still elusive, but it is thought to play a protective role against urinary tract infection, calcium oxalate crystal formation, and regulation of water and salt balance in the thick ascending limb. Mutations in uromodulin are responsible for autosomal-dominant kidney diseases characterized by defective urine concentrating ability, hyperuricemia, gout, tubulointerstitial fibrosis, renal cysts, and chronic kidney disease. Previous in vitro studies found retention in the endoplasmic reticulum as a common feature of all uromodulin mutant isoforms. Both in vitro and in vivo we found that mutant isoforms partially escaped retention in the endoplasmic reticulum and reached the plasma membrane where they formed large extracellular aggregates that have a dominant-negative effect on coexpressed wild-type protein. Notably, mutant uromodulin excretion was detected in patients carrying uromodulin mutations. Thus, our results suggest that mutant uromodulin exerts a gain-of-function effect that can be exerted by both intra- and extracellular forms of the protein

Isolation, identification and oenological characterization of non-Saccharomyces yeasts in a Mediterranean island

We isolated, identified and characterized yeast strains from grapes, and their fermented musts, sampled in the small island of Linosa, where there are no wineries and therefore the possibility of territory contamination by industrial strains is minimal. By traditional culture-dependent methods, we isolated 3805 colonies, distinguished by molecular methods in 17 different species. 544 isolates were analysed for the main oenological characteristics such as fermentative vigor with and without sulphites, sugar consumption, and production of alcohol, volatile acidity, hydrogen sulphide, glycerol and β-glucosidase. This analysis identified Kluyveromyces marxianus (seldomly used in winemaking) as the most interesting candidate yeast for the production of innovative wines. This article is protected by copyright. All rights reserved

Ramipril and Risk of Hyperkalemia in Chronic Hemodialysis Patients

Angiotensin converting enzyme (ACE) inhibitors provide well known cardiorenal-protective benefits added to antihypertensive effects in chronic renal disease. These agents are underused in management of patients receiving hemodialysis (HD) because of common concern of hyperkalemia. However, few studies have investigated effect of renin angiotensin aldosterone system (RAAS) blockade on serum potassium in hemodialysis patients. We assessed the safety of ramipril in patients on maintenance HD. We enrolled 28 adult end stage renal disease (ESRD) patients treated by maintenance HD and prescribed them ramipril in doses of 1.25 to 5 mg per day. They underwent serum potassium concentration measurements before ramipril introduction and in 1 to 3 months afterwards. No significant increase in kalemia was found. Results of our study encourage the use of ACE inhibitors in chronically hemodialyzed patients, but close potassium monitoring is mandatory

Influence of environmental patterns on the benthic faunal structure in the Kveithola Trough, NW Barents Sea

Per la prima volta, abbiamo documentato la struttura della comunità bentonica artica nel Kveithola Trough (NW Mare di Barents), per migliorare i gaps conoscitivi esistenti. Il Kveithola è caratterizzato da particolari condizioni morfo-deposizionali e idrografiche che permettono di distinguere tre aree principali (esterna, interna e il canale settentrionale). Nell'area esterna, l’elevato idrodinamismo contrasta l'accumulo di materia organica e la bassa biodisponibilità di carbonio organico nei sedimenti supporta una comunità con bassa richiesta di ossigeno. L’area interna e il canale settentrionale sono ambienti eutrofici, dominati da una comunità di detritivori (policheti subsurface-feeding Maldane sarsi e surface-feeding Lenvisenia gracilis, bivalvi lamellibranchia subsurface Mendicula cf. pigmea, protobranchia subsurface del genere Yoldiella), predatori appartenenti al phylum Nemertea, foraminiferi calcarei Nonionellina labradorica e Globobulimina auriculata, e agglutinanti Lagenammina difflugiformis. Questi taxa, delineano un ambiente con elevate concentrazioni di materia organica nel sedimento e impoverito di ossigeno (probabilmente legati alla presenza di cold seep) inoltre, sono anche responsabili di attività di bioturbazione. Interessante notare, in tutti i siti, l’elevata densità di morfotipi di foraminiferi monotalamici (Micrometula e Cylindrogullmia) che popolano tipicamente lo strato detritico dei fiordi artici e ambienti estremi poveri di ossigeno. Inoltre, i risultati della megafauna mostrano come nel sito 21, caratterizzato da un ambiente eterogeneo con strutture carbonatiche, tappeti microbici e vermi chemiosintetici, le emissioni di metano possano creare un hotspot di biomassa e diversità. Per concludere, le diverse caratteristiche geomorfologiche e ambientali, l'apporto di materia organica e la presenza di cold seep in questa area, rappresentano i fattori chiave della struttura della fauna bentonica e della loro distribuzione eterogenea.For the first time, we have documented the Arctic benthic faunal structure in the Kveithola Trough (NW Barents Sea), to improve knowledge gaps existing in this area. The Kveithola is characterized by peculiar morpho-depositional and hydrographic conditions, which allow to distinguish three main areas (the outer, the inner area and Northern channel). In the outer area, high hydrodynamic does not favour the accumulation of the organic matter and low sediment organic carbon bioavailability supports a poorly sediment community oxygen consumption. The inner part and Northern channel represent an eutrophic area, dominated by a detritivores community (subsurface-feeding polychaeta Maldane sarsi, the surface-feeding polychaeta Lenvisenia gracilis, the subsurface lamellibranch bivalve Mendicula cf. pigmea, the subsurface protobranch bivalve genus Yoldiella), predators belonging to Nemertea and foraminifera as calcareous Nonionellina labradorica, Globobulimina auriculata and agglutinated Lagenammina difflugiformis. These taxa indicate the presence of an organic-rich sediment and oxygen-depleted environment possibly linked to a cold seep system and are also responsible for the bioturbation activity. Interestingly, delicate foraminifera monothalamous morphotypes (Micrometula and Cylindrogullmia) were reported from all sites with high abundance percentage, they inhabit typically the detritus layer of Arctic fjords and live in an extremely oxygen-deficient environment. Meanwhile, megafauna results suggest the possibility of the methane emission creating a biomass and diversity hotspot on the site 21 seafloor, characterized by heterogeneous environment with carbonate structures, microbial mats and chemosynthetic worm tufts. To conclude, the distinct geomorphological and environmental feature, supply of organic matter and seep activity of this area, are key drivers of benthic faunal structure and their heterogeneity distribution