Search

SummaryCRISPR antiviral defense systems such as the well-known DNA-targeting Cas9- and the more complex RNA-targeting type III systems are widespread in bacteria and archea 1, 2. The type III systems can orchestrate a complex antiviral response that is initiated by the synthesis of cyclic oligoadenylates (cOAs) upon foreign RNA recognition 3–5. These second messenger molecules bind to the CARF (CRISPR associated Rossmann-fold) domains of dedicated effector proteins that are often DNAses, RNAses, or putative transcription factors 6. The activated effectors interfere with cellular pathways of the host, inducing cell death or a dormant state of the cell that is better suited to avoid propagation of the viral attack 7, 8. Among a large set of proteins that were predicted to be linked to the type III systems 9, 10, the CRISPR-Lon protein caught our attention. The protein was predicted to be an integral membrane protein containing a SAVED-instead of a CARF-domain as well as a Lon protease effector domain. Here, we report the crystal structure of CRISPR-Lon. The protein is a soluble monomer and indeed contains a SAVED domain that accommodates cA4. Further, we show that CRISPR-Lon forms a stable complex with the 34 kDa CRISPR-T protein. Upon activation by cA4, CRISPR-Lon specifically cleaves CRISRP-T, releasing CRISPR-T23, a 23 kDa fragment that is structurally very similar to MazF toxins and is likely a sequence specific nuclease. Our results describe the first cOA activated proteolytic enzyme and provide the first example of a SAVED domain connected to a type III CRISPR defense system. The use of a protease as a means to unleash a fast response against a threat has intriguing parallels to eukaryotic innate immunity.

The River Rhine is one of the few major fluvial systems that connect the areas of the Alpine glaciers and Scandinavian ice sheet and so provides a key for correlating the two glacial areas in northern and middle Europe. The fluvial sequences of the Rhine Valley include at least 11 Pleistocene terraces in the Lower Rhine area, 2 Pliocene and 12 Pleistocene terraces in the Middle Rhine area resulting in 15 different Pliocene and Pleistocene terraces based on the correlation between Lower and Middle Rhine. The formation of fluvial terraces is significantly influenced by climatic and tectonic processes. The terrace staircases are a result of uplift in the Middle Rhine area and the southern part of the Lower Rhine area, whereas subsidence in the northern part of the Lower Rhine area resulted in buried stacked sequences. Magnetostratigraphic data provide chronological constraints for the terrace deposits in the Lower Rhine embayment and Middle Rhine region. The Matuyama/Brunhes boundary is a reliable marker horizon for the Upper Terrace fluvial deposits exposed in the Karlich clay pit in the Middle Rhine area. The first appearance of volcanic heavy mineral grains in the terrace sediments, in loess and soils can be correlated from the Middle Rhine area through the Lower Rhine embayment to the Netherlands. The first occurrence of Nordic components in terrace sediments of the Lower Rhine area is known from gravel on top of the Kempen-Krefeld beds and so are younger than the Holsteinian but older than the penultimate glaciation. In the lower Middle Rhine area, 40Ar/39Ar dating of tephra layers intercalated in the aeolian and fluvial sediments provide age constraints. The Upper Pleistocene aeolian sediments overlying the terrace deposits have been dated by luminescence methods, and the tephra from the Laacher See eruption (12,860 BP) is present in the Younger Lower Terrace deposits.

Loess, loess-like sediments and the intercalated palaeosols along the bluffs of the river Yenisei provide a detailed Upper Pleistocene climate archive for the southern part of Middle Siberia. The section at Kurtak is one of the most detailed loess/palaeosol sequences in Middle Siberia. Two major periods of sediment accumulation were recorded in the sequence: the stratigraphically oldest one post-dating the last interglacial palaeosol and pre-dating the Kurtak Pedocomplex (oxygen isotope stage (OIS) 3); the younger one post-dating the Kurtak Pedocomplex and predating the Holocene soil. Three major phases of soil formation occurred during the Upper Pleistocene. The Kameny Log Pedocomplex (OIS 5e) consists of at least two pedogenetic episodes, a lower clayey chernozem forming during a more humid and warmer climate than today, and an upper chernozem representing a drier climate than today, the latter one including a well-pronounced carbonate-rich horizon. The Sukhoy Log Pedocomplex consists of a chernozem-like palaeosol and two kastanozjems (OIS 5c-a) and the Kurtak pedocomplex (OIS 3) with two chernozem-like palaeosols and up to three humic-rich layers. Additionally, weakly developed gleyed horizons are considered to represent palaeohydrological groundwater high levels. The results indicate a synchronous evolution of climate and environment change in both the more oceanic driven climate of West and Central Europe and Middle Siberia, as evidenced by luminescence dating results.

The Eastern Mediterranean Coastal Plain of Israel is composed mainly of loam and sand and gravel of Pleistocene to Holocene age, supplemented by an Upper Pleistocene beach rock horizon, indicating an alternation of marine, coastal and continental environments. Owing to the complexity of the numerous exposures of aeolianites (“kurkar”) and soils (“hamra”) in the elongated ridges along the coastal plain, it is difficult to set up a reliable stratigraphy. A systematic luminescence dating study was carried out on loose sand, kurkar and hamra deposits in the coastal plain between Netanya and Haifa. In this study, 33 samples were investigated from key sections along the Carmel coast. The chronological results are in excellent agreement with the geological estimates. Five periods of sand accumulation and kurkar formation can be distinguished at about 140, 130, 90 and around 60 ka and between 60 and 50 ka. Hamra formation took place between 140 and 130 ka, around 80, 65 and 60 ka and between 20 and 12 ka. The beach rock is correlated with the sea level maximum during OIS 5e. The luminescence dating results indicate that neither kurkar nor hamra formation correlates with glacial and interglacial periods of the Northern Hemisphere. However, the chronological succession of these climate-related cycles is in good agreement with marine and terrestrial archives in the Eastern Mediterranean.

The loess/palaeosol sequence of Kurtak, situated at the western bank of the upper Yenisei in Middle Siberia, represents one of the best developed Middle and Upper Pleistocene sediment records in Yenisei Siberia. More than 40 m thick loess and loess-like sediments intercalated by at least four pedocomplexes are exposed at a steep erosional slope at the bank of the Krasnoyarsk Water Reservoir. Infrared optically stimulated luminescence (IRSL) and thermoluminescence (TL) dating techniques have been applied on 38 fine grain samples from the upper 23 m of the profile, representing the penultimate and last interglacial–glacial cycle. The IRSL and TL age estimates are in good agreement with the geological estimates up to the last interglacial soil horizon (oxygen isotope substage (OIS) 5e). The luminescence ages show that the lowermost truncated palaeosol of kastanosjem-type is likely to have formed during the penultimate interglacial upon subaerial deposits. Three weak reddish brown palaeosols intercalated by reworked loess-like sediments correlate with early Upper Pleistocene interstadials (OIS5dion of -a), and a succession of humic horizons alternated by cryoturbation processes (Kurtak pedocomplex) is linked with OIS 3. Thick loess deposits between the pedocomplexes show now significant age increase with depth, indicating high accumulation rates at around 23 ka (OIS 2) and 60 ka (OIS 4).

The Sharon Coastal Plain in Israel is composed mainly of sand dune fields and aeolianite ridges. Three major sand accumulation periods are documented in the terrestrial record along the cliffs of the Sharon Coastal Plain, between 65 to 50 ka, from 7 to 5 ka and from 5 to 0.2 ka. These seem to correlate with the periods of sapropel formation in the Mediterranean Sea and so with periods of strongly increased African monsoon activity. The accumulation of the stratigraphically oldest aeolianite (Kurkar, Unit 5) appears to correlate with sapropel S2, formed about 55 ka BP. The uppermost aeolianite (calcareous sandstone, Unit 2) seems to correlate with sapropel S1, formed at about 7.8±4.0 ka BP. Major soil formations occurred between 35 and 25 ka resulting in a Rhodoxeralf soil/Grumusolic Dark Brown soil, and between 15 and 12 ka resulting in a Rhodoxeralf (hamra) soil. At least seven weak weathering horizons (regosol-type soils) are intercalated in the aeolianite of Unit V and two regosols are present in the Holocene aeolian sand of Unit I.

The coastal cliff at Netanya South in the Sharon Coastal Plain of Israel was investigated with luminescence dating methods. Twenty-four samples were taken from the exposed aeolianites and intercalated paleosols. The 24 IRSL and 24 TL age estimates suggest that the lower 45 m of the section were deposited in Oxygen Isotope Stage 3. The uppermost 7 m of the section are of Holocene age and clearly separated by a hiatus of 20–30 ka from the lower part.

The Eastern Mediterranean Coastal Plain of Israel is composed mainly of loam, sand and gravel of Pleistocene to Holocene age, indicating an alternation of marine, coastal and continental environments. Owing to the complexity of the numerous exposures of aeolianites (“kurkar”) and soils (“hamra”) in the elongated ridges along the coastal plain, it is difficult to set up a reliable stratigraphy. A systematic luminescence dating study was carried out on loose sand, kurkar and hamra deposits in the coastal plain between Netanya and Haifa. Sixteen samples were taken and investigated from the section at Givat Olga. The chronological results show excellent agreement between the infrared optically stimulated luminescence (IRSL) and thermoluminescence (TL) techniques, indicating that the former sand dunes were well-bleached prior to deposition. The IRSL and TL age estimates range from about 75–3 ka for the aeolianites indicating that this kurkar ridge formed during an older period of the last glaciation, likely before 50 ka.

The loess–palaeosol sequences of the Middle Rhine Area provide a relatively detailed and continuous terrestrial record of climate and environment change for the past 200,000 years. Loess–palaeosol sequences are generally well preserved in inter- and intra-crater depressions of late Middle Pleistocene scoria cones in the East Eifel Volcanic Field and on fluvial terraces of the lower middle terrace of the rivers Rhine and Moselle. Stratigraphic and chronological investigations of loess–palaeosol sequences from sections at Tonchesberg and Koblenz–Metternich in the Middle Rhine Area indicate that the last interglacial and glacial cycle is preserved in much more detail than previously thought. In both sections, the last interglacial soil is covered by at least ten palaeosols, postdating the Eemian (oxygen isotope (sub)stage, OIS 5e) brown forest soil.

Es wurden Schwermineralanalysen pleistozäner, pliozäner und oligozäner Sedimente am Mittelrhein statistisch aufgearbeitet, um unterschiedliche Sedimentationsräume am Mittelrhein zu kennzeichnen und die Ablagerungen stratigraphisch zu gliedern. Die Schwankungsbreite der Analysedaten wurde bestimmt. Die Faziesunterschiede innerhalb eines Aufschlusses wurden dabei als statistische Schwankungen in einem homogenen Schüttungskörper interpretiert., research

Bei Yiron treten auf Karbonatgesteinen der Oberkreide und des Alttertiärs tonige Bodensedimente auf. Lokal ist darin ein Kalk- und Flintschotter eingeschaltet, der altpaläolithische Artefakte führt. Ein inzwischen erosiv aufgelöster revers magnetisierter Deckbasalt bildet das Hangende. Er ist zum damals bereits angelegten Jordan-Graben hin orientiert. Die Artefakte müssen demnach älter sein als die Brunhes-Matuyama-Grenze. Sie gehören neben den Funden von Evron (nördlich Haifa) und Ubaidiya (Jordan-Graben) zu den ältesten Hinterlassenschaften des Menschen im Vorderen Orient. Ferner liegt eine ebenfalls relativ alte Faustkeil-Kultur auf den Plateaus von Yiron und Baram. Die Plateaus von Yiron und Baram lassen sich in geomorphologischer Hinsicht als ein flaches Hochtal interpretieren. Die weitere Entwicklung ist durch eine Kerbtal-Bildung gekennzeichnet., research

Es wurden Schwermineraluntersuchungen pleistozäner Sedimente am südlichen Mittelrhein bei Nochern durchgeführt. Ziel war es, Vorstellungen über die Fehlerquellen in der Schwermineralanalyse und ihre Größenordnung zu bekommen. Dazu wurden aus einem einheitlichen Terrassenkörper entlang von 3 Profilen Proben genommen. Die Analysenergebnisse wurden statistisch aufgearbeitet. Es hat sich für die untersuchten Sedimente gezeigt, daß bei der üblicherweise geringen Probenzahl die Zählung von 100 transparenten Körnern pro Präparat ausreichend ist. Eine Verbesserung der Ergebnisse kann sinnvoll nur durch Erhöhung der Probenzahl erreicht werden., research

Die sedimentologische und petrographische Bearbeitung der Braunkohlen-Deckschichten zeigt für die Niederrheinische Bucht im Miozän und Pliozän ein küstennahes Ablagerungsmilieu. Relativ kleinräumige Faziesverschiebungen und Schwankungen des Klimas zwischen feuchten und trockeneren Phasen verursachen die wechselnden Sedimentationstypen. Größere Relativbewegungen von Meeresspiegel zu Niederrheinischer Bucht sind nur über einige Erosionsdiskordanzen zu fassen. Im Pleistozän herrscht ausschließlich fluviatile Sedimentation, unterbrochen durch markante Erosionsphasen. Der Wechsel zwischen Erosion und Ablagerung und die Änderung in der petrographischen Zusammensetzung der Sedimente wird durch das Zusammenwirken von tektonischen Bewegungen und klimatischen Rhythmen des Altquartärs geprägt., research