Lake Store Finnsjøen – a key for understanding Lateglacial/early Holocene vegetation and ice sheet dynamics in the central Scandes Mountains

The Lateglacial (LG) deglaciation and vegetation development in the Scandes Mountains has been debated for a century. Here we present new evidence from microfossils, radiocarbon dated plant macrofossils and sedimentary ancient DNA from laminated sediments in Lake Store Finnsjøen (1260 m a.s.l.) at Dovre, Central Norway. Combined with previous results from three other Dovre lakes, this allows for new interpretations of events during and immediately after the LG deglaciation. The Finnsjøen sediments present the first uninterrupted record of local vegetation development in the Scandes Mountains from the late Younger Dryas (YD), ca 12,000 cal years BP, to the early Holocene around 9700 cal years BP. The local vegetation in late YD/early Holocene was extremely sparse with pioneer herbs (e.g. Artemisia norvegica, Beckwithia, Campanula cf. uniflora, Koenigia, Oxyria, Papaver, Saxifraga spp.) and dwarf-shrubs (Betula nana, Salix including Salix polaris). From 11,300 cal years BP, local vegetation rapidly closed with dominant Dryas, Saxifraga spp., and Silene acaulis. From ca 10,700 cal years BP, open birch-forests with juniper, Empetrum nigrum and other dwarf-shrubs developed. Pine forests established within the area from 10,300 cal years BP. We identified the cold Preboreal Oscillation (PBO), not earlier described from pollen data in South Norway, around 11,400 cal years BP by a regional pollen signal. Distinct local vegetation changes were not detected until the post-PBO warming around 11,300 cal years BP. Apparently, the earlier warming at the YD/Holocene transition at 11,650 cal years BP was too weak and short-lived for vegetation closure at high altitudes at Dovre. For the first time, we demonstrate a regional glacier readvance and local ice cap formations during the YD in the Scandes Mountains. In two of the deep lakes with small catchments, YD glaciation blocked sedimentation without removing old sediments and caused a hiatus separating sediments of the ice-free LG interstadial (LGI) from those of the ice-free Holocene period. Both regional glaciers and local ice caps caused hiati. Ice-free pre-YD conditions at Dovre followed by a YD readvance point to a scenario that is intermediate between the maximum ice model postulating a thick glacier during the entire LG, and the minimum ice model postulating thin and multi-domed early LG ice

A regulatable transgene expression system for cultured Plasmodium falciparum parasites

<p>Abstract</p> <p>Background</p> <p>The ability to transfect and create transgenic cultured malaria parasites has transformed the study of <it>Plasmodium falciparum </it>over the last decade. With the completion of the annotated genome sequence, the process of gene discovery now routinely includes gene knockouts, over-expression and complementation analysis. However, while this technology has proven extremely valuable, significant limitations exist. In particular, <it>P. falciparum </it>DNA is often unstable and difficult to clone because of its AT-rich, repetitive nature. As a result, transgene expression constructs can be difficult to assemble due to the need to include two expression cassettes on a single plasmid, one to drive expression of the transgene of interest and a second for expression of the selectable marker. In addition, transgene expression levels are usually not regulatable, making it difficult to assess phenotypes that are sensitive to the amount of protein expressed.</p> <p>Results</p> <p>A plasmid based system for transgene expression is described that uses a single, bidirectional promoter to drive expression of both the transgene and the selectable marker, thus greatly reducing the size of the construct and enhancing stability. Further, by altering the concentration of drug used for selection, it is possible to modulate the copy number of the concatameric episomes and thereby regulate the expression level of the transgene through a range greater than 10 fold.</p> <p>Conclusion</p> <p>The transgene expression system described here should prove useful for both routine protein over-expression and complementation experiments as well as for experiments in which precisely manipulating the expression level of candidate proteins is desirable. This should provide an additional level of precision to the tools used to study the molecular biology of malaria parasites.</p

Studying Li dynamics in a gas-phase synthesized amorphous oxide by NMR and impedance spectroscopy

Li diffusion parameters of a structurally disordered Li-Al-Si-oxide prepared by gas-phase synthesis were complementarily investigated by both time-domain NMR techniques and impedance spectroscopy. The first include 7Li NMR spin-lattice relaxation (SLR) measurements in the laboratory as well as in the rotating frame of reference. An analysis of variable-temperature NMR line widths point to an activation energy E a of approximately 0.6 eV. The value is confirmed by rotating-frame SLR NMR data recorded at approximately 11 kHz. Above room temperature the low-temperature flank of a diffusion-induced rate peak shows up which can be approximated by an Arrhenius law yielding E a = 0.56(1) eV. This is in very good agreement with the result obtained from 7Li spin-alignment echo (SAE) NMR being sensitive to even slower Li dynamics. For comparison, dc-conductivity measurements, probing long-range motions, yield E a = 0.8 eV. Interestingly, lowtemperature SAE NMR decay rates point to localized Li motions being characterized with a very small activation energy of only 0.09 eV. © by Oldenbourg Wissenschaftsverlag, München

Antibodies against multiple merozoite surface antigens of the human malaria parasite Plasmodium falciparum inhibit parasite maturation and red blood cell invasion

BACKGROUND: Plasmodium falciparum merozoites expose at their surface a large protein complex, which is composed of fragments of merozoite surface protein 1 (MSP-1; called MSP-183, MSP-130, MSP-138, and MSP-142) plus associated processing products of MSP-6 and MSP-7. During erythrocyte invasion this complex, as well as an integral membrane protein called apical membrane antigen-1 (AMA-1), is shed from the parasite surface following specific proteolysis. Components of the MSP-1/6/7 complex and AMA-1 are presently under development as malaria vaccines. METHODS: The specificities and effects of antibodies directed against MSP-1, MSP-6, MSP-7 on the growth of blood stage parasites were studied using ELISA and the pLDH-assay. To understand the mode of action of these antibodies, their effects on processing of MSP-1 and AMA-1 on the surface of merozoites were investigated. RESULTS: Antibodies targeting epitopes located throughout the MSP-1/6/7 complex interfere with shedding of MSP-1, and as a consequence prevent erythrocyte invasion. Antibodies targeting the MSP-1/6/7 complex have no effect on the processing and shedding of AMA-1 and, similarly, antibodies blocking the shedding of AMA-1 do not affect cleavage of MSP-1, suggesting completely independent functions of these proteins during invasion. Furthermore, some epitopes, although eliciting highly inhibitory antibodies, are only poorly recognized by the immune system when presented in the structural context of the intact antigen. CONCLUSIONS: The findings reported provide further support for the development of vaccines based on MSP-1/6/7 and AMA-1, which would possibly include a combination of these antigens

Reductions in microfilaridermia by repeated ivermectin treatment are associated with lower Plasmodium-specific Th17 immune responses in Onchocerca volvulus-infected individuals

Background: 37 million individuals are currently infected with Onchocerca volvulus (O. volvulus), a parasitic nematode that elicits various dermal manifestations and eye damage in man. Disease control is primarily based on distributing ivermectin in mass drug administration (MDA) programmes which aim at breaking transmission by eliminating microfilariae (MF), the worm's offspring. The majority of infected individuals present generalized onchocerciasis, which is characterized by hyporesponsive immune responses and high parasite burden including MF. Recently, in areas that have been part of MDA programmes, individuals have been identified that present nodules but are amicrofilaridermic (a-MF) and our previous study showed that this group has a distinct immune profile. Expanding on those findings we determined the immune responses of O. volvulus-infected individuals to a Plasmodium-derived antigen MSP-1 (merozoite surface protein-1), which is required by the parasite to enter erythrocytes. Methods: Isolated PBMCs from O. volvulus-infected individuals (164 MF+ and 46 a-MF) and non-infected volunteers from the same region (NEN), were stimulated with MSP-1 and the resulting supernatant screened for the presence of IL-5, IL-13, IFN-γ, TNF-α, IL-6, IL-17A and IL-10. These findings were then further analyzed following regression analysis using the covariates MF, ivermectin (IVM) and region. The latter referred to the Central or Ashanti regions of Ghana, which, at the time sampling, had received 8 or 1 round of MDA respectively. Results: IL-5, IL-13 and IFN-γ responses to MSP-1 were not altered between NEN and O. volvulus-infected individuals nor were any associations revealed in the regression analysis. IL-10, IL-6 and TNF-α MSP-1 responses were, however, significantly elevated in cultures from infected individuals. Interestingly, when compared to a-MF individuals, MSP-induced IL-17A responses were significantly higher in MF+ patients. Following multivariable regression analysis these IL-10, IL-6, TNF-α and IL-17A responses were all dominantly associated with the regional covariate. Conclusions: Consequently, areas with a lowered infection pressure due to IVM MDA appear to influence bystander responses to Plasmodium-derived antigens in community members even if they have not regularly participated in the therapy

Emotional burnout of specialists in socio-occupational professions: contemporary views on the problem

Представлено сучасні підходи до проблеми вигорання у представників соціономічних професій у контексті емоційної праці, емоційного і когнітивного дисонансу. Проаналізовано й узагальнено наукову літературу з питань вигорання, визначено три основні його компоненти: емоційне і/або фізичне виснаження, зниження продуктивності праці і надмірна деперсоналізація. На основі аналізу визначень вигорання встановлено його зв’язок з емоційною працею (регуляцією і вираженням емоційних станів). Обстоюється думка, що фахівці соціономічних професій особливо вразливі до вигорання, оскільки тривалий час перебувають у стані, коли необхідно постійно контролювати свої емоції, брати на себе відповідальність і відчувати невизначеність, працюючи з іншими людьми. Емоційну працю розглянуто як предиктор вигорання у фахівців соціономічних професій. На основі аналізу літератури, присвяченої проблемам вигорання та емоційного дисонансу, висловлено припущення, що вимоги щодо емоційної праці зумовлюють різноманітність проявів синдрому виго-рання (у тому числі виснаження, цинізму, зниження продуктивності праці та погіршення самопочуття), а знання симптомів вигорання дало б змогу фахівцям соціономічних професій запобігти виникненню та загостренню цього стану.This article deals with the modern approaches to the problem of burnout of helping professionals in the context of emotional labor, emotional and cognitive dissonance. The burnout literature is reviewed, compared, and summarized. The definition of burnout is proposed including three components: emotional and/or physical exhaustion, lowered work productivity, and excessive depersonalization. Based on an analysis of the definitions of burnout, the paper focuses on the connec-tion of burnout and emotional work (regulation of feelings and emotional expression). It is also maintained a fact that helping professionals are especially vulnerable to burnout because of the necessity to control own emotions for a long time, to take responsibilities, and to feel uncertainties they encounter while working with others. The current study discussed emotional labor as a predictor of burnout of helping professionals. On the basis of the literature on burnout and emotional dissonance, the author of this article hypothesized that emotional job demands would explain variances of burnout (i.e., exhaustion and cynicism). Knowledge of abovementioned syndromes would help socionomy professionals to avoid emergence and aggravation of emotional burnout.Представлены современные подходы к проблеме выгорания у представителей социономических профессий в контексте эмоциональной труда, эмоционального и когнитивного диссонанса. Проанализированы и обобщены научную литературу по вопросам выгорания, определены три основные его компоненты: эмоциональное и / или физическое истощение, снижение производительности труда и чрезмерная деперсонализация. На основе анализа определений выгорания установлена ​​его связь с эмоциональной трудом (регуляцией и выражением эмоциональных состояний). Отстаивается мнение, что специалисты социономических профессий особенно уязвимы к выгоранию, поскольку длительное время находятся в состоянии, когда необходимо постоянно контролировать свои эмоции, брать на себя ответственность и чувствовать неопределенность, работая с другими людьми. Эмоциональный труд рассмотрен как предиктор выгорания у специалистов социономических профессий. На основе анализа литературы, посвященной проблемам выгорания и эмоционального диссонанса, высказано предположение, что требования по эмоциональной труда обусловливают разнообразие проявлений синдрома выгорания (в том числе истощения, цинизма, снижение производительности труда и ухудшение самочувствия), а знание симптомов выгорания позволило бы специалистам социономических профессий предотвратить возникновение и обострение этого состояния

Highly overlapping winter diet in two sympatric lemming species revealed by DNA metabarcoding

Sympatric species are expected to minimize competition by partitioning resources, especially when these are limited. Herbivores inhabiting the High Arctic in winter are a prime example of a situation where food availability is anticipated to be low, and thus reduced diet overlap is expected. We present here the first assessment of diet overlap of high arctic lemmings during winter based on DNA metabarcoding of feces. In contrast to previous analyses based on microhistology, we found that the diets of both collared (Dicrostonyx groenlandicus) and brown lemmings (Lemmus trimucronatus) on Bylot Island were dominated by Salix while mosses, which were significantly consumed only by the brown lemming, were a relatively minor food item. The most abundant plant taxon, Cassiope tetragona, which alone composes more than 50% of the available plant biomass, was not detected in feces and can thus be considered to be non-food. Most plant taxa that were identified as food items were consumed in proportion to their availability and none were clearly selected for. The resulting high diet overlap, together with a lack of habitat segregation, indicates a high potential for resource competition between the two lemming species. However, Salix is abundant in the winter habitats of lemmings on Bylot Island and the nonSalix portion of the diets differed between the two species. Also, lemming grazing impact on vegetation during winter in the study area is negligible. Hence, it seems likely that the high potential for resource competition predicted between these two species did not translate into actual competition. This illustrates that even in environments with low primary productivity food resources do not necessarily generate strong competition among herbivores

Processing of Plasmodium falciparum Merozoite Surface Protein MSP1 activates a Spectrin-binding function enabling parasite egress from RBCs

The malaria parasite Plasmodium falciparum replicates within erythrocytes, producing progeny merozoites that are released from infected cells via a poorly understood process called egress. The most abundant merozoite surface protein, MSP1, is synthesized as a large precursor that undergoes proteolytic maturation by the parasite protease SUB1 just prior to egress. The function of MSP1 and its processing are unknown. Here we show that SUB1-mediated processing of MSP1 is important for parasite viability. Processing modifies the secondary structure of MSP1 and activates its capacity to bind spectrin, a molecular scaffold protein that is the major component of the host erythrocyte cytoskeleton. Parasites expressing an inefficiently processed MSP1 mutant show delayed egress, and merozoites lacking surface-bound MSP1 display a severe egress defect. Our results indicate that interactions between SUB1-processed merozoite surface MSP1 and the spectrin network of the erythrocyte cytoskeleton facilitate host erythrocyte rupture to enable parasite egress