University of Potsdam

About: University of Potsdam is a education organization based out in Potsdam, Germany. It is known for research contribution in the topics: Population & Computer science. The organization has 9629 authors who have published 26740 publications receiving 759745 citations. The organization is also known as: Universität Potsdam.

Transitory microbial habitat in the hyperarid Atacama Desert

Abstract: Traces of life are nearly ubiquitous on Earth. However, a central unresolved question is whether these traces always indicate an active microbial community or whether, in extreme environments, such as hyperarid deserts, they instead reflect just dormant or dead cells. Although microbial biomass and diversity decrease with increasing aridity in the Atacama Desert, we provide multiple lines of evidence for the presence of an at times metabolically active, microbial community in one of the driest places on Earth. We base this observation on four major lines of evidence: (i) a physico-chemical characterization of the soil habitability after an exceptional rain event, (ii) identified biomolecules indicative of potentially active cells [e.g., presence of ATP, phospholipid fatty acids (PLFAs), metabolites, and enzymatic activity], (iii) measurements of in situ replication rates of genomes of uncultivated bacteria reconstructed from selected samples, and (iv) microbial community patterns specific to soil parameters and depths. We infer that the microbial populations have undergone selection and adaptation in response to their specific soil microenvironment and in particular to the degree of aridity. Collectively, our results highlight that even the hyperarid Atacama Desert can provide a habitable environment for microorganisms that allows them to become metabolically active following an episodic increase in moisture and that once it decreases, so does the activity of the microbiota. These results have implications for the prospect of life on other planets such as Mars, which has transitioned from an earlier wetter environment to today's extreme hyperaridity.

Pan-African high-pressure metamorphism in the Precambrian basement of the Menderes massif, Western Anatolia, Turkey

Abstract: The Menderes Massif is made up of Pan-African basement and a Paleozoic to Early Tertiary cover sequence imbricated by Late Alpine deformation. The Precambrian basement comprises primarily medium- to high-grade schists, paragneisses, migmatites, orthogneisses, metagranites, charnockites, and metagabbros. High-pressure relics in the Pan-African basement are divided into two groups: eclogites and eclogitic metagabbros. The mineral assemblage in the eclogites is omphacite (Jd 44)–garnet–clinozoisite–rutile. The eclogites occur as pods and boudinaged layers in the basement schists and paragneisses. Inclusions found in the cores of the garnets indicate a medium-pressure protolith. The eclogitic metagabbros are closely related to Precambrian gabbroic stocks. The igneous texture and relic magmatic phases are preserved in these high-pressure rocks, which are characterized by the mineral assemblage omphacite (Jd 25)–garnet–rutile±kyanite. The P–T conditions of the Pan-African high-pressure metamorphism in the eclogites are estimated to be 644°C with a minimum pressure of approximately 15 kbar. The eclogites are partly to completely retrograded to garnet amphibolites by a Barrovian-type overprint which developed under isothermal decompression conditions. For this post-eclogitic event, the P–T estimates are 7 kbar and 623°C. The eclogite relics provide strong support for a correlation of the Menderes Massif with the Bitlis Massif in terms of common Pan-African high-pressure evolution.

High‐pressure metasediments in central Turkey: Constraints on the Neotethyan closure history

Abstract: [1] The distribution of oceanic domains and continental blocks in Central Anatolia remains a challenge in understanding the Alpine geodynamic evolution of the Tethys realm. The consumption of a Neotethys oceanic branch at the Mesozoic-Cenozoic boundary welded the Central Anatolian Crystalline Complex in central Turkey and the Anatolide-Tauride Block in western Turkey, with the northerly Eurasian margin. Whether those two regions constituted a single or two distinct continental masses is still matter of debate. High-pressure metamorphism has been locally evidenced in the Afyon Zone, which was, however, defined as a greenschist-facies metamorphic zone of the Anatolide-Tauride Block. Since the Afyon Zone composes a metamorphic equivalent of a continental margin exposed far south of the Izmir-Ankara suture zone, this encouraged us to reevaluate its metamorphic evolution in order to better understand the relation between western and central Turkey. Our investigations reveal that the high-pressure minerals Fe-Mg-carpholite and glaucophane are present in the entire Afyon Zone, which we reconsider as a blueschist-facies zone. We additionally present a tectonic reconstruction, stripping off the postcollisional tectonics. It reveals that today's bending of the high-pressure belt is consistent with an Eocene collision of the Anatolide-Tauride Block around the southern edge of the Central Anatolian Crystalline Complex. We argue that the Central Anatolian Crystalline Complex and the Anatolide-Tauride Block were two distinct continental masses separated by a Neotethyan oceanic stripe, the closure of which engendered subduction-related metamorphism in the latter and arc volcanism and high-grade metamorphism in the former by late Cretaceous to early Cenozoic.

DPP-4 Inhibition on top of angiotensin receptor blockade offers a new therapeutic approach for diabetic nephropathy

Abstract: Background: The need for an improved treatment for diabetic nephropathy is greatest in patients who do not adequately respond to angiotensin II receptor blockers (ARBs). This study investigated the effect of the novel dipeptidyl peptidase-4 inhibitor linagliptin alone and in combination with the ARB telmisartan on the progression of diabetic nephropathy in diabetic endothelial nitric oxide synthase (eNOS) knockout mice. Methods: Sixty male eNOS knockout C57BL/6J mice were divided into four groups after receiving intraperitoneal highdose streptozotocin: telmisartan (1 mg/kg), linagliptin (3 mg/kg), linagliptin + telmisartan (3 mg/kg + 1 mg/kg) and vehicle. Fourteen mice were used as non-diabetic controls. Results: After 12 weeks, urine and blood were obtained and blood pressure measured. Glucose concentrations were increased and similar in all diabetic groups. Telmisartan alone reduced systolic blood pressure by 5.9 mmHg versus diabetic controls (111.2 ± 2.3 mmHg vs 117.1 ± 2.2 mmHg; mean ± SEM; P=0.071). Combined treatment significantly reduced albuminuria compared with diabetic controls (71.7 ± 15.3 μg/24 h vs 170.8 ± 34.2 μg/24 h; P=0.017), whereas the effects of single treatment with either telmisartan (97.8 ± 26.4 μg/24 h) or linagliptin (120.8 ± 37.7 μg/24 h) were not statistically significant. DPP-4 inhibition, alone and in combination, led to significantly lower plasma osteopontin levels compared with telmisartan alone. Histological analysis revealed reduced glomerulosclerosis after Linagliptin alone and in combination with telmisartan in comparison to non treated diabetic animals