Chemoenzymatic synthesis and immunological studies of Xylosylated N-glycans

307 p.Glycosylation is one of the most common post-translational modifications in eukaryotic cells. It changes during cell development and differentiation and it is tissue and more importantly, species specific. While core ¿-1,6 fucose and/or terminal sialyl residues are typical mammalian features, most of the plant, insects and parasite derived N-glycans contain core ¿-1,3-fucose, ß-1,2-xylose and other terminal motifs. In mammals, some of these glycan elements are believed to be at least partially involved in the stimulation or regulation of immune responses in parasite infected individuals and in the pathophysiology of food allergens. In this Thesis, the chemoenzymatic synthesis of 39 core xylosylated N-glycans is described. Using glycan microarray-assisted studies, the carbohydrate interaction with biologically relevant glycan binding proteins such as plant lectins and animal C-type lectin receptors has been evaluated. Additionally, glycan microarrays were employed for the screening of anti-carbohydrate antibodies raised against S. mansoni parasites. The immune response induced in patients from endemic areas has been compared and the potential biological role of different glycan families is discussed.CIC BioGun

Working Memory Capacity as a Predictor of Cognitive Training Efficacy in the Elderly Population

Aging is associated with a decline in a wide range of cognitive functions and working memory (WM) deterioration is considered a main factor contributing to this. Therefore, any attempt to counteract WM decline seems to have a potential benefit for older adults. However, determination of whether such methods like WM trainings are effective is a subject of a serious debate in the literature. Despite a substantial number of training studies and several meta-analyses, there is no agreement on the matter of their effectiveness. The other important and still not fully explored issue is the impact of the preexisting level of intellectual functioning on the training’s outcome. In our study we investigated the impact of WM training on variety of cognitive tasks performance among older adults and the impact of the initial WM capacity (WMC) on the training efficiency. 85 healthy older adults (55–81 years of age; 55 female, 30 males) received 5 weeks of training on adaptive dual N-back task (experimental group) or memory quiz (active controls). Cognitive performance was assessed before and after intervention with measures of WM, memory updating, inhibition, attention shifting, short-term memory (STM) and reasoning. We found post-intervention group independent improvements across all cognitive tests except for inhibition and STM. With multi-level analysis individual learning curves were modeled, which enabled examining of the intra-individual change in training and inter-individual differences in intra-individual changes. We observed a systematic and positive, but relatively small, learning trend with time. Moderator analyses with demographic characteristics as moderators showed no additional effects on learning curves. Only initial WMC level was a significant moderator of training effectiveness. Older adults with initially lower WMC improved less and reached lower levels of performance, compared to the group with higher WMC. Overall, our findings are in accordance with the research suggesting that post-training gains are within reach of older adults. Our data provide evidence supporting the presence of transfer after N-back training in older adults. More importantly, our findings suggest that it is more important to take into account an initial WMC level, rather than demographic characteristics when evaluating WM training in older adults

Początki przekładu filozoficznego w Polsce

The article constitutes an attempt to present some of the oldest translations of philosophy into Polish using the methodology suggested by Lieven D’hulst, based on the seemingly simple model: Quis? Quid? Ubi? Quibus auxiliis? Cur? Quomodo? Quando? Cui bono? (Who? What? Where? With whose help? Why? How? When? For whose sake?). In the introduction, the author presents the state of historical research, primarily that in French, and attempts to contextualise in it the study of philosophical translation, understood as non-literary translation. The most important works in historical translation studies are quoted – for example, The History of Translations into French (Histoire des traductions en langue française) – and proposals for Translator Studies are propounded. The latter are compared to the methodology proffered by D’hulst. Next, six works are presented: the first translations of Aristotle and Cicero into Polish. All works discussed date back to the late 16th and early 17th centuries and were published in Łosk (in the Grand Duchy of Lithuania) and Kraków. In accordance with D’hulst’s guidelines, the paper places equal emphasis on such elements of analysis as the translators (Quis?) and other people involved in the publishing of the translated works (Quibus auxiliis?), the context in which the translations were created (Ubi? Quando?), and elements of translation strategy (Quomodo?). The latter were studied using the method of comparative analysis of the translators’ strategies, mostly in the context of philosophical terms. Elements of domestication and foreignization as well as the presence of the translator’s paratext were considered. In the summary the author attempts to briefly answer the question of the influence of these texts on Polish readers (Cui bono?).Artykuł stanowi próbę przedstawienia jednych z najstarszych polskich przekładów filozoficznych z wykorzystaniem metody zaproponowanej przez Lievena D’hulsta w Essais d’histoire de la traduction. Avatars de Janus. Na wstępie przedmiot badania umieszczony zostaje w kontekście historycznych badań przekładoznawczych. Następnie przedstawione zostają pierwsze polskie tłumaczenia Arystotelesa i Cycerona. Zgodnie z wytycznymi D’hulsta opracowanie stawia na równi takie elementy jak postaci tłumaczy, kontekst powstania czy strategie translatorskie. W ramach podsumowania autorka stara się krótko odpowiedzieć na pytanie o wpływ omawianych przekładów na polskich odbiorców

Czy mówimy o tym samym? Analiza porównawcza pojęcia „umysł” w wybranych językach europejskich

W refleksji nad naturą i własnościami ludzkiego umysłu warto zatrzymać się nad genezą samego pojęcia umysłu w naszej kulturze, czy też raczej nad genezą słowa „umysł” w różnych językach europejskich, a także nad jego aktualną semantyką. Niniejszy tekst ma na celu ukazanie bogactwa pola semantycznego umysłowości, jak również zasygnalizowanie wpływu języka potocznego na specjalistyczny język filozofii. Omawiane poniżej pojęcia są analizowane z punktu widzenia języka, a przytaczane teksty filozoficzne są przedstawione wybiórczo i mają być jedynie ilustracją omawianych znaczeń, nie zaś analizą filozoficzną. Innymi słowy, praca ta ma odgrywać swego rodzaju służebną rolę wobec filozofii, przedstawiając semantyczną  różnorodność związaną z pojęciem umysłu

Chemoenzymatic synthesis and immunological studies of Xylosylated N-glycans

307 p.Glycosylation is one of the most common post-translational modifications in eukaryotic cells. It changes during cell development and differentiation and it is tissue and more importantly, species specific. While core ¿-1,6 fucose and/or terminal sialyl residues are typical mammalian features, most of the plant, insects and parasite derived N-glycans contain core ¿-1,3-fucose, ß-1,2-xylose and other terminal motifs. In mammals, some of these glycan elements are believed to be at least partially involved in the stimulation or regulation of immune responses in parasite infected individuals and in the pathophysiology of food allergens. In this Thesis, the chemoenzymatic synthesis of 39 core xylosylated N-glycans is described. Using glycan microarray-assisted studies, the carbohydrate interaction with biologically relevant glycan binding proteins such as plant lectins and animal C-type lectin receptors has been evaluated. Additionally, glycan microarrays were employed for the screening of anti-carbohydrate antibodies raised against S. mansoni parasites. The immune response induced in patients from endemic areas has been compared and the potential biological role of different glycan families is discussed.CIC BioGun

Combined Phase-Rate Coding by Persistently Active Neurons as a Mechanism for Maintaining Multiple Items in Working Memory in Humans

Maintaining multiple items in working memory (WM) is central to human behavior. Persistently active neurons are thought to be a mechanism to maintain WMs, but it remains unclear how such activity is coordinated when multiple items are kept in memory. We show that memoranda-selective persistently active neurons in the human medial temporal lobe phase lock to ongoing slow-frequency (1–7 Hz) oscillations during WM maintenance. The properties of phase locking are dependent on memory content and load. During high memory loads, the phase of the oscillatory activity to which neurons phase lock provides information about memory content not available in the firing rate of the neurons. We provide a computational model that reveals that inhibitory-feedback-mediated competition between multiple persistently active neurons reproduces this phenomenon. This work reveals a mechanism for the active maintenance of multiple items in WM that relies on persistently active neurons whose activation is orchestrated by oscillatory activity

Combined Phase-Rate Coding by Persistently Active Neurons as a Mechanism for Maintaining Multiple Items in Working Memory in Humans

Maintaining multiple items in working memory (WM) is central to human behavior. Persistently active neurons are thought to be a mechanism to maintain WMs, but it remains unclear how such activity is coordinated when multiple items are kept in memory. We show that memoranda-selective persistently active neurons in the human medial temporal lobe phase lock to ongoing slow-frequency (1–7 Hz) oscillations during WM maintenance. The properties of phase locking are dependent on memory content and load. During high memory loads, the phase of the oscillatory activity to which neurons phase lock provides information about memory content not available in the firing rate of the neurons. We provide a computational model that reveals that inhibitory-feedback-mediated competition between multiple persistently active neurons reproduces this phenomenon. This work reveals a mechanism for the active maintenance of multiple items in WM that relies on persistently active neurons whose activation is orchestrated by oscillatory activity

Development of Embryo Suspensors for Five Genera of Crassulaceae with Special Emphasis on Plasmodesmata Distribution and Ultrastructure

The suspensor in the majority of angiosperms is an evolutionally conserved embryonic structure functioning as a conduit that connects ovule tissues with the embryo proper for nutrients and growth factors flux. This is the first study serving the purpose of investigating the correlation between suspensor types and plasmodesmata (PD), by the ultrastructure of this organ in respect of its full development. The special attention is paid to PD in representatives of Crassulaceae genera: Sedum, Aeonium, Monanthes, Aichryson and Echeveria. The contribution of the suspensor in transporting nutrients to the embryo was confirmed by the basal cell structure of the suspensor which produced, on the micropylar side of all genera investigated, a branched haustorium protruding into the surrounding ovular tissue and with wall ingrowths typically associated with cell transfer. The cytoplasm of the basal cell was rich in endoplasmic reticulum, mitochondria, dictyosomes, specialized plastids, microtubules, microbodies and lipid droplets. The basal cell sustained a symplasmic connection with endosperm and neighboring suspensor cells. Our results indicated the dependence of PD ultrastructure on the type of suspensor development: (i) simple PD are assigned to an uniseriate filamentous suspensor and (ii) PD with an electron-dense material are formed in a multiseriate suspensor. The occurrence of only one or both types of PD seems to be specific for the species but not for the genus. Indeed, in the two tested species of Sedum (with the distinct uniseriate/multiseriate suspensors), a diversity in the structure of PD depends on the developmental pattern of the suspensor. In all other genera (with the multiseriate type of development of the suspensor), the one type of electron-dense PD was observed

Working Memory Load-related Theta Power Decreases in Dorsolateral Prefrontal Cortex Predict Individual Differences in Performance

Holding information in working memory (WM) is an active and effortful process that is accompanied by sustained load-dependent changes in oscillatory brain activity. These proportional power increases are often reported in EEG studies recording theta over frontal midline sites. Intracranial recordings, however, yield mixed results, depending on the brain area being recorded from. We recorded intracranial EEG with depth electrodes in 13 patients with epilepsy that were performing a Sternberg WM task. Here, we investigated patterns of theta power changes as a function of memory load during maintenance in three areas critical for WM: dorsolateral prefrontal cortex (DLPFC), dorsal ACC (dACC), and hippocampus. Theta frequency power in both hippocampus and dACC increased during maintenance. In contrast, theta frequency power in the DLPFC decreased during maintenance, and this decrease was proportional to memory load. Only the power decreases in DLPFC, but not the power increases in hippocampus and dACC, were predictive of behavior in a given trial. The extent of the load-related theta power decreases in the DLPFC in a given participant predicted a participant's RTs, revealing that DLPFC theta explains individual differences in WM ability between participants. Together, these data reveal a pattern of theta power decreases in the DLPFC that is predictive of behavior and that is opposite of that in other brain areas. This result suggests that theta band power changes serve different cognitive functions in different brain areas and specifically that theta power decreases in DLPFC have an important role in maintenance of information