Paleolimnological evidences for the rise and fall of a star-like planktonic diatom (Asterionella formosa) during the Anthropocene = Paleolimnológiai adatok egy csillagszerű, planktonikus kovaalga, az Asterionella formosa „tündökléséről és bukásáról” az Antropocénban

Asterionella formosa is known as a common and often dominant planktonic diatom in mesotrophic and eutrophic lakes worldwide. The bone-shaped Asterionella cells often form colonies consisting usually of eight cells, but the number of cells can reach up to 20 cells. The colonies are star shaped, and this shape slowing down settling velocity can makes them dominant in low viscosity warm water. Recently the abundance of this species increases in oligotrophic lakes as well. It is a rather well established fact, that the proliferation of A. formosa correlates with nutrient enrichment, especially when atmospheric nitrogen deposition intensifies in the lakes. However, there are increasing numbers of paleolimnological evidence, that other factor may be responsible for the spreading of this diatom. High-resolution, multi-proxy study was carried out on a sedimentary record obtained from Lake Ighiel (46°10’50"N, 23°22’00"E). Lake Ighiel is located in Alba County, Romania, in the south-eastern part of the Trascaului Mountains in the Romanian Carpathians. This small lake is located in a mid-altitude mountain belt at 924 m above sea level, with a maximum depth of 9 m and a catchment area of 487 hectare. The here presented results are focussing on the increase and decrease of A. formosa abundance. Lake Ighiel was formed ca. 6000 years ago, however the siliceous algae were able to preserve in the sediment from ca. 4800 cal yr BP. After the dominance of small fragilaroids, the Middle Holocene (ca 4800– 4200 cal yr BP) is marked clearly by a relative increase in benthic Navicula and Gyrosigma taxa, indicating habitat diversification. There is an episodic return to small fragilaroids from 2600 to 2500 cal yr BP with some periphitic taxa becoming abundant. In the last 1000 years A. formosa increases in relative abundance, reaching dominance in the last 200 years, while before it had been only sporadic in the sedimentary record. We can assume a strong positive correlation between the abundance of A. formosa and global warming. Probably development of soil also influences contribution of this species to the diatom assemblage. The period of the II. World War is imprinted as a decline of A. formosa in the assemblage. Global warming related changes, like longer open water periods, changing mixing regimes and thermal properties of water might have contributed to the increased abundance of A. formosa. In the last couple of years the „star” of Asterionella dramatically and abruptly fell, while the small celled Centrales taxa practically replaced it in the lake sediment. To disentangle if nutrient supply and/or climate are main driving force on diatom distribution is an unsolved problem. The authors acknowledge financial support from OTKA 119208, CRYPTIC project

Constraining Holocene hydrological changes in the Carpathian–Balkan region using speleothem δ18O and pollen-based temperature reconstructions

Here we present a speleothem isotope record (POM2) from Ascunsă Cave (Romania) that provides new data on past climate changes in the Carpathian–Balkan region from 8.2 ka until the present. This paper describes an approach to constrain the effect of temperature changes on calcite δ18O values in stalagmite POM2 over the course of the middle Holocene (6–4 ka), and across the 8.2 and 3.2 ka rapid climate change events. Independent pollen temperature reconstructions are used to this purpose. The approach combines the temperature-dependent isotope fractionation of rain water during condensation and fractionation resulting from calcite precipitation at the given cave temperature. The only prior assumptions are that pollen-derived average annual temperature reflects average cave temperature, and that pollen-derived coldest and warmest month temperatures reflect the range of condensation temperatures of rain above the cave site. This approach constrains a range of values between which speleothem δ18O changes should be found if controlled only by surface temperature variations at the cave site. Deviations of the change in δ18Ocspel values from the calculated temperature-constrained range of change are interpreted towards large-scale variability of climate–hydrology. Following this approach, we show that an additional ∼0.6‰ enrichment of δ18Oc in the POM2 stalagmite was caused by changing hydrological patterns in SW Romania across the middle Holocene, most likely comprising local evaporation from the soil and an increase in Mediterranean moisture δ18O. Further, by extending the calculations to other speleothem records from around the entire Mediterranean basin, it appears that all eastern Mediterranean speleothems recorded a similar isotopic enrichment due to changing hydrology, whereas all changes recorded in speleothems from the western Mediterranean are fully explained by temperature variation alone. This highlights a different hydrological evolution between the two sides of the Mediterranean. Our results also demonstrate that during the 8.2 ka event, POM2 stable isotope data essentially fit the temperature-constrained isotopic variability. In the case of the 3.2 ka event, an additional climate-related hydrological factor is more evident. This implies a different rainfall pattern in the Southern Carpathian region during this event at the end of the Bronze Age

Exceptionally high levels of lead pollution in the Balkans from the Early Bronze Age to the Industrial Revolution

The Balkans are considered the birthplace of mineral resource exploitation and metalworking in Europe. However, since knowledge of the timing and extent of metallurgy in southeastern Europe is largely constrained by discontinuous archaeological findings, the long-term environmental impact of past mineral resource exploitation is not fully understood. Here we present a high resolution and continuous geochemical record from a peat bog in western Serbia, providing for the first time a clear indication of extent and magnitude of environmental pollution in this region, and a context in which to place archaeological findings. We observe initial evidence of anthropogenic lead (Pb) pollution during the earliest part of the Bronze Age (c.3600 yr before Common Era (BCE)), the earliest such evidence documented in European environmental records. A steady, almost linear increase in Pb concentration after 600 BCE, until circa 1600 CE is observed, documenting the development in both sophistication and extent of southeastern European metallurgical activity throughout Antiquity and the Medieval Period. This provides a new view on the history of mineral exploitation in Europe, with metal-related pollution not ceasing at the fall of the western Roman Empire, as was the case in western Europe. Further comparison with other Pb pollution records indicates the the amount of Pb deposited in the Balkans during the Medieval Period was if not greater, at least similar to records located close to western European mining regions, suggestive of the key role the Balkans have played in mineral resource exploitation in Europe over the last 5600 years

Detrital events and hydroclimate variability in the Romanian Carpathians during the Mid-to-Late Holocene

The Romanian Carpathians are located at the confluence of three major atmospheric pressure fields: the North Atlantic, the Mediterranean and the Siberian. Despite its importance for understanding past human impact and climate change, high-resolution palaeoenvironmental reconstructions of Holocene hydroclimate variability, and in particular records of extreme precipitation events in the area, are rare. Here we present a 7500-year-long high-resolution record of past climatic change and human impact recorded in a peatbog from the Southern Carpathians, integrating palynological, geochemical and sedimentological proxies. Natural climate fluctuations appear to be dominant until 4500 years before present (yr BP), followed by increasing importance of human impact. Sedimentological and geochemical analyses document regular minerogenic deposition within the bog, linked to periods of high precipitation. Such minerogenic depositional events began 4000 yr BP, with increased depositional rates during the Medieval Warm Period (MWP), the Little Ice Age (LIA) and during periods of societal upheaval (e.g. the Roman conquest of Dacia). The timing of minerogenic events appears to indicate a teleconnection between major shifts in North Atlantic Oscillation (NAO) and hydroclimate variability in southeastern Europe, with increased minerogenic deposition correlating to low NAO index values. By linking the minerogenic deposition to precipitation variability, we state that this link persists throughout the mid-to-late Holocene

Disordered proteins and network disorder in network descriptions of protein structure, dynamics and function. Hypotheses and a comprehensive review

During the last decade, network approaches became a powerful tool to describe protein structure and dynamics. Here we review the links between disordered proteins and the associated networks, and describe the consequences of local, mesoscopic and global network disorder on changes in protein structure and dynamics. We introduce a new classification of protein networks into ‘cumulus-type’, i.e., those similar to puffy (white) clouds, and ‘stratus-type’, i.e., those similar to flat, dense (dark) low-lying clouds, and relate these network types to protein disorder dynamics and to differences in energy transmission processes. In the first class, there is limited overlap between the modules, which implies higher rigidity of the individual units; there the conformational changes can be described by an ‘energy transfer’ mechanism. In the second class, the topology presents a compact structure with significant overlap between the modules; there the conformational changes can be described by ‘multi-trajectories’; that is, multiple highly populated pathways. We further propose that disordered protein regions evolved to help other protein segments reach ‘rarely visited’ but functionally-related states. We also show the role of disorder in ‘spatial games’ of amino acids; highlight the effects of intrinsically disordered proteins (IDPs) on cellular networks and list some possible studies linking protein disorder and protein structure networks

Anthropogenic impact and environmental pollution over Southeastern Europe during the last 8000 years

Here we present newly acquired high-resolution geochemical (major and trace elements) and lead isotopic data (206Pb, 207Pb, 208Pb, 204Pb,) on several peat records from the Carpathians that cover most of the Holocene, with a special focus over periods with enhanced human impact on the environment, such as the Early Metal Ages, the Antiquity, Medieval and the recent past. We distinguish signatures related to the natural cycling of elements from the anthropogenic contributions due to natural resource exploitation, mining, and smelting activities. Together with existing geological, archaeological, and archaeometric evidences, our results provide a comprehensive record on the long-term history of metal-use development in the Carpathian region. Through a comparison with records from other parts of Europe we document the existence of strong regional differences in the magnitude, temporal, as well as spatial shifts in our understanding of past emission sources. We therefore show that the existing picture of past pollution load and temporal variability at the European scale is incomplete because it is mainly based on western records without considering the long-term pollution inputs from southeastern Europe, a region with significant mineral endowment and long-lasting human impact on the environment driven by the early rise of agricultural and metal processing activitie

Cellular forgetting, desensitisation, stress and aging in signalling networks. When do cells refuse to learn more?

Recent findings show that single, non-neuronal cells are also able to learn signalling responses developing cellular memory. In cellular learning nodes of signalling networks strengthen their interactions e.g. by the conformational memory of intrinsically disordered proteins, protein translocation, miRNAs, lncRNAs, chromatin memory and signalling cascades. This can be described by a generalized, unicellular Hebbian learning process, where those signalling connections, which participate in learning, become stronger. Here we review those scenarios, where cellular signalling is not only repeated in a few times (when learning occurs), but becomes too frequent, too large, or too complex and overloads the cell. This leads to desensitisation of signalling networks by decoupling signalling components, receptor internalization, and consequent downregulation. These molecular processes are examples of anti-Hebbian learning and forgetting of signalling networks. Stress can be perceived as signalling overload inducing the desensitisation of signalling pathways. Aging occurs by the summative effects of cumulative stress downregulating signalling. We propose that cellular learning desensitisation, stress and aging may be placed along the same axis of more and more intensive (prolonged or repeated) signalling. We discuss how cells might discriminate between repeated and unexpected signals, and highlight the Hebbian and anti-Hebbian mechanisms behind the fold-change detection in the NF-\k{appa}B signalling pathway. We list drug design methods using Hebbian learning (such as chemically-induced proximity) and clinical treatment modalities inducing (cancer, drug allergies) desensitisation or avoiding drug-induced desensitisation. A better discrimination between cellular learning, desensitisation and stress may open novel directions in drug design, e.g., helping to overcome drug-resistance.Comment: 19 pages, 4 figure

Network strategies to understand the aging process and help age-related drug design

Recent studies have demonstrated that network approaches are highly appropriate tools to understand the extreme complexity of the aging process. The generality of the network concept helps to define and study the aging of technological, social networks and ecosystems, which may give novel concepts to cure age-related diseases. The current review focuses on the role of protein-protein interaction networks (interactomes) in aging. Hubs and inter-modular elements of both interactomes and signaling networks are key regulators of the aging process. Aging induces an increase in the permeability of several cellular compartments, such as the cell nucleus, introducing gross changes in the representation of network structures. The large overlap between aging genes and genes of age-related major diseases makes drugs which aid healthy aging promising candidates for the prevention and treatment of age-related diseases, such as cancer, atherosclerosis, diabetes and neurodegenerative disorders. We also discuss a number of possible research options to further explore the potential of the network concept in this important field, and show that multi-target drugs (representing "magic-buckshots" instead of the traditional "magic bullets") may become an especially useful class of age-related future drugs.Comment: an invited paper to Genome Medicine with 8 pages, 2 figures, 1 table and 46 reference

Base metal pollution as a result of historical ore smelting in the Romanian Carpathians throughout the Holocene

In Europe the characteristics, distribution and effects of recent pollution are well known, with monitoring observations existing at a continental scale. However, estimates of long-term pollution are restricted to central-western Europe, the British Isles and Scandinavia. In Eastern Europe in particular, the lack of such estimates has led to incomplete understanding of regional differences. When coupled to the insufficient knowledge of past emission sources and isotopic signatures of various ores, it is clear there are gaps in our knowledge of the history of pollution in this area. As a result, the causal relationships between humans and the environment are insufficiently explored, particularly within the Carpathian region - one with significant mineral wealth and a long history of human presenc