Uptake of macromolecules by cercariae during skin penetration and transformation to schistosomula (Schistosoma mansoni)

Here, we observed the uptake of membrane-impermeant molecules by cercariae as they penetrate the skin and are transformed into schistosomula. We propose that membrane-impermeant molecules, Lucifer Yellow, Propidium iodide and Hoechst 33258 enter the parasite through both thenephridiopore and the surface membrane and then diffuse throughout the body of the parasite. We present a hypothesis that the internal cells of the body of the schistosomulum represent a new host-parasite interface, at which skin-derived growth factors may stimulate receptors on internal membranes during transformation of the cercariae into the schistosomulum

Summer paleohydrology during the Late Glacial and Early Holocene based on δ2H and δ18O from Bichlersee, Bavaria.

Isotope-based records provide valuable information on past climate changes. However, it is not always trivial to disentangle past changes in the isotopic composition of precipitation from possible changes in evaporative enrichment, and seasonality may need to be considered. Here, we analyzed δ2H on n-alkanes and δ18O on hemicellulose sugars in sediments from Bichlersee, Bavaria, covering the Late Glacial and Early Holocene. Our δ2Hn-C31 record documents past changes in the isotopic composition of summer precipitation and roughly shows the isotope pattern known from Greenland. Both records show lower values during the Younger Dryas, but at Bichlersee the signal is less pronounced, corroborating earlier suggestions that the Younger Dryas was mainly a winter phenomenon and less extreme during summer. δ18Ofucose records the isotopic composition of the lake water during summer and is sensitive to evaporative enrichment. Coupling δ2Hn-C31 and δ18Ofucose allows calculating lake water deuterium-excess and thus disentangling changes in the isotopic composition of precipitation and evaporative enrichment. Our deuterium-excess record reveals that the warm Bølling-Allerød and Early Holocene were characterized by more evaporative enrichment compared to the colder Younger Dryas. Site-specific hydrological conditions, seasonality, and coupling δ2H and δ18O are thus important when interpreting isotope records

Soil organic carbon cycling in a long-term agricultural experiment,Switzerland

Soils are one of the largest organic carbon pools and changes in the carbon release from soils has considerable impact on the composition of atmospheric CO2. Alongside the accelerated carbon release from soils by anthro-pogenic warming (Crowther et al., 2016), agricultural use strongly affects soil organic carbon (SOC) (Johnstonet al., 2009). Conversion from conventional to organic farming has been suggested a valuable contribution to sequester SOC providing a great mitigation potential within agricultural practices (Smith et al., 2008).Here we present SOC contents and 14C activity under two different farming practices in the long-termagricultural DOK trial at Therwil, Switzerland (Mäder et al., 2002). In this long-lasting agricultural experiment, we compare biodynamic farming (biodyn), which receives manure and biodynamic preparations, with conventional farming (conmin), which receives only mineral fertilizers. We analyzed functional SOC fractions from both farming practices for SOC concentration and radiocarbon (∆14C) in two soil layers (0-20 cm and 20-50 cm).Three SOC fractions were obtained by density and particle size fractionation: particular organic matter (POM,labile pool), mineral-associated organic matter 20μm (MOM >20μm, labile pool).Our results clearly show higher SOC concentrations for biodyn compared to conmin in all SOC fractions in the upper soil layer (0-20 cm). In the subsoil (20-50 cm) we found a negligible influence of farming practices with depth. High ∆14C values in the POM and >20μm fraction indicated that they are a more labile and fastcycling carbon pool, whereas lower∆14C values in the 20μm fraction, with higher ∆14C values in the biodyn system suggesting greater input of fresh plant material with a faster turnover

Late Holocene climate changes in the Altai Region based on a first high‐resolution biomarker isotope record from Lake Khar Nuur

The Late Holocene marks a substantial cultural and economic transition in the eastern Eurasian Steppe and Altai Region with the dispersal of nomadic pastoralism. So far, paleoclimate conditions during this time remain unclear and controversial. Here, we present a high-resolution 4.2 ka paleoclimate record from Lake Khar Nuur in the Mongolian Altai that is based on lake sediment proxies and biomarker compound-specific δ2H analyses. Our results document increased aridity before ∼3.7 cal. ka BP, followed by two pronounced phases of warm and wet conditions from ∼3.5–2.8 to ∼2.3–1.5 cal. ka BP, and a strong increase in aridity since ∼1.5 cal. ka BP. Phases of warmer and wetter conditions coincide with a negative North Atlantic Oscillation, which has been responsible for advecting moisture into the region by more southerly-displaced Westerlies and possibly favored the expansion of mobile nomadic pastoralism in the region

Central Mongolian lake sediments reveal new insights on climate change and equestrian empires in the Eastern Steppes

The repeated expansion of East Asian steppe cultures was a key driver of Eurasian history, forging new social, economic, and biological links across the continent. Climate has been suggested as important driver of these poorly understood cultural expansions, but paleoclimate records from the Mongolian Plateau often suffer from poor age control or ambiguous proxy interpretation. Here, we use a combination of geochemical analyses and comprehensive radiocarbon dating to establish the first robust and detailed record of paleohydrological conditions for Lake Telmen, Mongolia, covering the past ~ 4000 years. Our record shows that humid conditions coincided with solar minima, and hydrological modeling confirms the high sensitivity of the lake to paleoclimate changes. Careful comparisons with archaeological and historical records suggest that in the vast semi-arid grasslands of eastern Eurasia, solar minima led to reduced temperatures, less evaporation, and high biomass production, expanding the power base for pastoral economies and horse cavalry. Our findings suggest a crucial link between temperature dynamics in the Eastern Steppe and key social developments, such as the emergence of pastoral empires, and fuel concerns that global warming enhances water scarcity in the semi-arid regions of interior Eurasia

Holocene Temperature Variations in Semi-Arid Central Mongolia—A Chronological and Sedimentological Perspective From a 7400-year Lake Sediment Record From the Khangai Mountains

Semi-arid Mongolia is a highly sensitive region to climate changes, but the region’s Holocene paleoclimatic evolution and its underlying forcing mechanisms have been the subject of much recent debate. Here we present a continuous 7.4 ka sediment record from the high-altitude Shireet Naiman Nuur (Nuur = lake) in the central Mongolian Khangai Mountains. We extensively dated the sediments and analyzed elemental composition and bulk isotopes for lake sediment characterization. Our results show that 14C-dating of bulk organic carbon and terrestrial macrofossils provide a robust and precise chronology for the past 7.4 ± 0.3 cal ka BP at Shireet Naiman Nuur and 14C-ages are mostly in stratigraphic order. The 14C-based chronology is confirmed by paleomagnetic secular variations, which resemble the predictions of spherical harmonic geomagnetic field models. The very good chronological control makes paleomagnetic secular variation stratigraphy a powerful tool for evaluating and refining regional 14C-chronologies when compared to the record presented here. The lake sediment proxies TOC, N, log (Ca/Ti) and log (Si/Ti) reveal increased lake primary productivity and high growing season temperatures from 7.4 ± 0.3 to 4.3 ± 0.2 cal ka BP, which is likely the result of stronger summer insolation and pronounced warming. Reduced summer insolation thereafter results in decreased productivity and low growing season temperatures at Shireet Naiman Nuur from 4.3 ± 0.3 cal ka BP until present day. The globally acknowledged 4.2 ka event also appears as a pronounced cooling event at Shireet Naiman Nuur, and additional abrupt cooling events occurred during minima in total solar irradiance at ~3.4, 2.8 and 2.4 ka BP. Low lake primary productivity and growing season temperatures are likely the result of longer ice cover periods at the high-altitude (2,429m a.s.l.) Shireet Naiman Nuur. This leads to shorter mixing periods of the lake water which is supported by more positive δ13CTOC because of increased incorporation of dissolved HCO3− by aquatic producers during periods of longer ice cover

Jahreshefte des Vereins für Vaterländische Naturkunde in Württemberg : zugl. Jahrbuch d. Staatlichen Museums für Naturkunde in Stuttgart

JAHRESHEFTE DES VEREINS FÜR VATERLÄNDISCHE NATURKUNDE IN WÜRTTEMBERG : ZUGL. JAHRBUCH D. STAATLICHEN MUSEUMS FÜR NATURKUNDE IN STUTTGART Jahreshefte des Vereins für Vaterländische Naturkunde in Württemberg : zugl. Jahrbuch d. Staatlichen Museums für Naturkunde in Stuttgart (-) Jahreshefte des Vereins für Vaterländische Naturkunde in Württemberg : zugl. Jahrbuch d. Staatlichen Museums für Naturkunde in Stuttgart (Bd. 45, 1889) (-) Titelseite (-) Inhalt (-) I. Angelegenheiten des Vereins ([1]) Bericht über die dreiundvierzigste Generalversammlung vom 24. Juni 1888 in Crailsheim (F. v. Krauß) ([1]) Rechenschaftsbericht für das jahr 1887/1888 (F. v. Krauß) (5) Zuwachsverzeichnisse der Vereinssammlungen (F. v. Krauß, v. Ahles) (9) Rechnungsabschluss für das Jahr 1887/1888 (Ed. Seyffardt) (24) Wahl der Beamten und des Versammlungsorts (28) Nekrolog des Grafen Kurt von Degenfeld-Schonburg ([30]) Nekrolog des Hofapotheker Anton Ducke ([34]) Nekrolog des Pfarrer Dr. Karl Albert Kemmler ([36]) II. Vorträge ([40]) Beiträge zur Mineralogie Württembergs. II. Die Versteinerungs- und Vererzungsmittel der schwäbischen Petrefakten (Leuze) ([40]) Über Grenzlinien in der Trias (O. Fraas) (56) Einiges zur Geologie des Muschelkals und der Lettenkohle (Bertsch) (58) Über die Fortpflanzung des Proteus anguneus uns seine Larve (Zeller) (64) [III. Abhandlungen] ([65]) Über einige Gegenstände aus dem Gebiet der Geophysik ([65]) Psammochelys Keuperina ([120]) Über die Fortpflanzung des Proteus anguineus und seine Larve ([131]) Naturwissenschaftlicher Jahresbericht 1887 ([139]) Loliginites (Geoteuthis) Zitteli EB. FRAAS. Ein vollständig erhaltener Dibranchiate aus den Laibsteinen des Lias ([217]) Kopfstacheln von Hybodus und Acrodus, sog. Ceratodus heteromorphus AG. ([233]) Über die Kreuzschnäbel und ihre Fortpflanzung. Eine monographische Studie ([241]) Über ein angebliches Vorkommen gediegenen Zinns und über die spezifischen Gewichte der Zinnbleilegierungen ([292]) Die Mineralien und Pseudomorphen des Roseneggs ([305]) Erdbebenkommission. Übersicht über die in Württemberg und Hohenzollern in der Zeit vom 1. März 1888 bis zum 28. Februar 1889 wahrgenommenen Erderschütterungen ([341]) Beitrag zur Kenntnis der Pleistocänen Fauna Oberschwabens ([359]) Beiträge zur Fauna der Umgebung von Tübingen ([361]) Tafel I (Tafel 1) Tafel II (Tafel 2) Tafel III (Tafel 3) Tafel IV (Tafel 4) Tafel V (Tafel 5) Tafel VI (Tafel 6) Tafel VII (Tafel 7) Tafel VIII: Verbreitungsgebiet des Erdbebens vom 7. Januar 1889 (Tafel 8