Enzyme-Polymer Conjugates to Enhance Enzyme Shelf Life in a Liquid Detergent Formulation

Herein, the synthesis of enzyme–polymer conjugates is reported. Four different activated polymers (mPEG-aldehyde, mPEG-NHS, maltodextrin-aldehyde, carboxymethyl cellulose aldehyde) are conjugated to the surface of protease, α-amylase, and lipase using two different strategies (reductive amination and alkylation with NHS-activated acid). Although the chemical modification of the enzymes is accompanied by losses in enzyme activity (maximum loss 40%), the covalent attachment of polymers increases the thermal stability and the stability in a standard detergent formulation compared to the unmodified enzymes. The enzyme–polymer conjugates are characterized by asymmetrical-flow field-flow fractionation and differential scanning microcalorimetry. Furthermore, it is demonstrated that conjugated enzymes still show performance in a real washing process. Enzyme–polymer conjugates show a potential as a stabilizing system for enzymes in detergents

Théophile de Viau : étude bio-bibliographique, avec une pièce inédite du poète et un tableau généalogique / par Jules Andrieu,...

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The Role of Catastrophic Floods Generated by Collapse of Natural Dams Since the Neolithic in the Oases of Bukhara and Qaraqöl: Preliminary Results

International audienceThe history of the civilizations of the oases of Bukhara and Qaraqöl (southeastern Uzbekistan) since the Neolithic in relation to environmental changes is studied by the French/Uzbekistan Archaeological Mission in Bukhara 1 following pioneering Russian studies 2. Using a methodology tested in Afghanistan, the geoarchaeological side of the program focused on the drawing of a regional geomorphological map then on the identification, mapping and dating of the paleochannels of the river Zerafshan. We established the chronology of several generations of fluvial channels in relation to archaeological settlements of different eras (Early Neolithic, Neolithic, Bronze Age, Iron Age and Islamic period) and with optically stimulated luminescence dating of alluvial deposits. Based on preliminary results of these OSL dates we propose and discuss a regional environmental reconstruction. We hypothesize that the main cause of avulsion could be catastrophic floods generated by collapse of natural dams in the upper part of the Zerafshan River

First evidence of a lake at Ancient Phaistos (Messara Plain, South-Central Crete, Greece): Reconstructing paleoenvironments and differentiating the roles of human land-use and paleoclimate from Minoan to Roman times

International audiencePhaistos was one of the most important Minoan palaces in Crete and previous studies have addressed its relationship with the paleo-seashore position during historical times. Here, we reconstruct the environmental evolution of Phaistos from Early Minoan to Roman times. Study of two stratigraphic sections and nine boreholes drilled in the westernmost part of the Messara Plain has revealed the stratigraphy of the Mid-to Late-Holocene sediments. Laboratory analyses comprise granulometry, magnetic susceptibility measurements and identification of mollusks, diatoms and pollen grains. Eighteen radiocarbon dates provide a robust chronostratigraphy. In addition, a geophysical survey (electric resistivity tomography (ERT) method) was conducted to reveal the sub-surface morphology in the coring area. The results reveal that a freshwater lake existed from ca. 2100-2000 BC to ca. 1200-1100 BC, which subsequently became swampland until ca. 700 BC. A lake retreat is identified at ca. 1200-1000 BC and can be interpreted as resulting from the 3.2 cal kyr BP rapid climate change (RCC) dry event, observed elsewhere in the Eastern Mediterranean. Subsequently, from the 7th to the 5th century BC, there was the input of detrital material and fluvial dynamics prevailed until at least Roman times. The origin of the lake and its disappearance are discussed in the context of regional climate change and local tectonic activity, without excluding possible human influences. We also reconstruct the vegetation history for the period from the Late Minoan to the Early Archaic period. Pollen analysis reveals a Mediterranean maquis landscape dominated by Olea, together with hygrophilous vegetation, and highlights a clear transition from limnic to swampy environmental conditions around 1100 BC. The pollen sequence is also important for assessing the impact of the 3.2 cal. kyr BP RCC event and for assessing the possibility of an abrupt discontinuity in human activity around Phaistos after the demise of the Minoan Civilization

Indian summer monsoon variations could have affected the early Holocene woodland expansion in the Near East

Postglacial expansion of deciduous oak woodlands of the Zagros—Anti-Taurus Mountains, a major biome of the Near East, was delayed until the middle Holocene at ~6300 cal. yr BP. The current hypotheses explain this delay as a consequence of a regional aridity during the early Holocene, slow migration rates of forest trees, and/or a long history of land use and agro-pastoralism in this region. In the present paper, support is given to a hypothesis that suggests different precipitation seasonalities during the early Holocene compared with the late Holocene. The oak species of the Zagros—Anti-Taurus Mts, particularly Quercus brantii Lindl., are strongly dependent on spring precipitation for regeneration and are sensitive to a long dry season. Detailed analysis of modern atmospheric circulation patterns in SW Asia during the late spring suggests that the Indian Summer Monsoon (ISM) intensification can modify the amount of late spring and/or early summer rainfall in western/northwestern Iran and eastern Anatolia, which could in turn have controlled the development of the Zagros—Anti-Taurus deciduous oak woodlands. During the early Holocene, the northwestward shift of the Inter-Tropical Convergence Zone (ITCZ) could have displaced the subtropical anticyclonic belt or associated high pressure ridges to the northwest. The latter could, in turn, have prevented the southeastward penetration of low pressure systems originating from the North Atlantic and Black Sea regions. Such atmospheric configuration could have reduced or eliminated the spring precipitation creating a typical Mediterranean continental climate characterized by winter-dominated precipitation. This scenario highlights the complexity of biome response to climate system interactions in transitional climatic and biogeographical regions