Peptidylarginine Deiminase (PAD) and Post-Translational Protein Deimination—Novel Insights into Alveolata Metabolism, Epigenetic Regulation and Host–Pathogen Interactions

The alveolates (Superphylum Alveolata) comprise a group of primarily single-celled eukaryotes that have adopted extremely diverse modes of nutrition, such as predation, photoautotrophy and parasitism. The alveolates consists of several major phyla including the apicomplexans, a large group of unicellular, spore forming obligate intracellular parasites, and chromerids, which are believed to be the phototrophic ancestors of the parasitic apicomplexans. Molecular pathways involved in Alveolata host–pathogen interactions, epigenetic regulation and metabolism in parasite development remain to be fully understood. Peptidylarginine deiminases (PADs) are a phylogenetically conserved enzyme family which causes post-translational protein deimination, affecting protein function through the conversion of arginine to citrulline in a wide range of target proteins, contributing to protein moonlighting in physiological and pathological processes. The identification of deiminated protein targets in alveolate parasites may therefore provide novel insight into pathogen survival and host-pathogen interactions. The current study assessed PAD homologues and deiminated protein profiles of two alveolate parasites, Piridium sociabile (Chromerida) and Merocystis kathae (Apicomplexa). Histological analysis verified strong cytoplasmic PAD expression in both Alveolates, detected deiminated proteins in nuclear and cytoplasmic compartments of the alveolate parasites and verified the presence of citrullinated histone H3 in Alveolata nucleus, indicating roles in epigenetic regulation. Histone H3 citrullination was also found significantly elevated in the host tissue, indicative of neutrophil extracellular trap formation, a host-defence mechanism against a range of pathogens, particularly those that are too large for phagocytosis. Proteomic analysis of deiminated proteins from both Alveolata identified GO and KEGG pathways strongly relating to metabolic and genetic regulation, with some species-specific differences between the apicomplexan and the chromerid. Our findings provide novel insights into roles for the conserved PAD/ADI enzyme family in the regulation of metabolic and epigenetic pathways in alveolate parasites, possibly also relating to their life cycle and host–pathogen interactions

Parasites of Redfish (Sebastes spp.) in Icelandic Waters

Sphyrion lumpi is a marine ectoparasitic copepod that has a significant negative impact on fisheries of redfish, Sebastes spp. in the North Atlantic as it reduces the commercial value of the fillets. Long-term data of infestation by S. lumpi and abnormalities in Sebastes mentella, in Icelandic waters were analyzed in this study. Five categories of external abnormalities were applied; black spots, red spots, mixed spots, remnants or lesions caused by S. lumpi and the parasite itself. Infestation intensity of the copepod was not found to be related to redfish condition (K). During the period, the prevalence of S. lumpi infections declined from 25% in 1995 to 9% in 2013. Significant differences in infestations were found between female and male fish and the shallow pelagic and deep pelagic stock. These results show the host response of S. lumpi infections and give a good overall view of trends in S. lumpi infestation, which could be a contributing factor towards defining S. mentella population stock structure. Microparasites in the field of icthyoparasitology are generally limited to Myxozoa (Kingdom Animalia, Phylum Cnidaria), Protozoa (Kingdom Protista) and Microsporidia (Kingdom Fungi). The microparasitic fauna of Sebastes spp. in Icelandic waters was mapped in this study. All major organs were examined thoroughly with a stereoscope and/or a compound microscope. Histopathological examinations were carried out with regards to parasitic infections in order to determine the exact site of the infection. DNA was extracted from myxozoans from the gallbladder and apicomplexans from the intestines and the urinary bladder. The parasites’ DNA was amplified with PCR and sequenced. Six different parasite species were identified, two myxosporeans and four apicomplexans. Results identified the myxosporean species to be Myxidium bergense and Ceratomyxa adeli. The apicomlexan species are not fully identified but are thought to be previously undescribed. Accurate identification awaits further study

Uppbyggingastefna í grunnskólum : þróun og ávinningur : "Hefðir þú getað gert eitthvað verra?"

Samskipti skipta miklu máli í daglegu lífi, hér var skoðað á þverfaglegan hátt hvernig uppbyggingastefnan (Restitution) eða uppeldi til ábyrgðar hefur reynst og þróast í þeim skólum sem hafa tileinkað sér stefnuna. Leitast var við að svara hvort notendur telji hana gagnlega sem samskipta og agatæki sem gæti dregið úr kvíða, auðveldað samskipti og fækkað alvarlegum agamálum í skólum. Viðmælendur voru á aldrinum 15-62 ára, alls 17 einstaklingar, valdir af handahófi, kynjahalli var á rannsókninni þar sem aðeins 1 karlmaður var þátttakandi. Hálfopin djúpviðtöl voru tekin við skólastjóra, kennara og aðra starfsmenn skólana ásamt nemendum í 5 skólum bæði á höfuðborgarsvæðinu og á landsbyggðinni, rannsóknaraðferðin var fyrirbærafræði (Sigríður Halldórsdóttir, 2013), en stuðst var við viðtalsramma sem gerður var til að draga fram áhersluatriði rannsóknarinnar. Niðurstöður rannsóknarinnar benda til að uppbyggingastefnan virki vel sem samskipta- og agastefna sem geti, sérstaklega ef vel er staðið að framkvæmd og eftirfylgni, bætt samskiptafærni og sjálfþekkingu notenda ásamt því að draga úr kvíða þó hún nái ekki til allra. Skólarnir nota aðrar agaaðferðir samhliða uppbyggingastefnunni fyrir þá sem eiga erfitt með að nýta sér aðferðafræðina, eins og jákvæða umbun, PMTO eða hluta af CAT-kassanum til að auka hlutfall þeirra sem ná að nýta sér tæknina og hafa þróað stefnuna á mismunandi hátt.Communication is important in every day life, a cross-sectional study was performed in an attempt to seek answers about experience and development of Restitution in elementary and secondary school. Emphasis was on Restitution as a communication and a discipline tool which had the potential to reduce anxiety, improve understanding, communication and reduce serious disciplinary matters. Data was collected in semi-open interviews with principals, teachers, other staff and school children from 15 to 62 of age, both in the capital city and the rural area. The research method was Phenomenology (Sigríður Halldórsdóttir, 2013) and a interview frame especially created for the study. The research findings indicates that the restitution method is effective for most individuals, but not all and can be useful to reduce anxiety and improve communication skills, especially if the daily use and follow up is done correctly. The Schools use other methods with the restitution method to increase the percentage of successful users, like PMTO, positive reward and some form of Cognitive Affective Training and have developed in different ways

Connections between emotional dependency and interventions in cognitive behaviour therapy for adults : outcomes of group therapy

Emotional dependency is defined as a strong tendency to let feelings control oneself on behaviour, thoughts and decisions. Cognitive Behaviour Therapy (CBT) can be an effective tool in working with feelings, behaviour and negative thinking when treating mental health disorders such as depression and anxiety or in improving self-esteem. Purpose of homework is to facilitate the generalization and maintenance of CBT skills. The aim of the current study is to examine whether emotional dependency is connected to participants' regular use of CBT methods and if participants considered CBT helpful for diminishing the symptoms of anxiety, depression, stress and low self-esteem. Six self-evaluation questionnaires were presented to 41 participants on three selected measure points over four weeks treatment period for each group. The results showed improvement, over four weeks of CBT group therapy, on depression, self-esteem, anxiety, and stress. The pre- to post-treatment effect sizes (Cohen’s d) for depression (ES = 0.79) and stress (ES = 0.52) were medium but small for anxiety (ES = 0.24). A smaller proportion of participants with low self-esteem (29%) adopted regular use of CBT compared to participants with depression or anxiety (71%). Participants who used the method of CBT consistently showed less emotional dependence by the end of the course compared to those who did not use CBT over the time of the course. Where there was no significant difference in the beginning and middle measurements, the results indicate that CBT diminish personal emotional dependence rather than emotional dependency would reduce participants´ capacity to use CBT in a homework situation. Keywords: cognitive behavioural therapy, emotional dependency, interventions, group therapy

Peptidylarginine Deiminase (PAD) and Post-Translational Protein Deimination—Novel Insights into Alveolata Metabolism, Epigenetic Regulation and Host–Pathogen Interactions

The alveolates (Superphylum Alveolata) comprise a group of primarily single-celled eukaryotes that have adopted extremely diverse modes of nutrition, such as predation, photoautotrophy and parasitism. The alveolates consists of several major phyla including the apicomplexans, a large group of unicellular, spore forming obligate intracellular parasites, and chromerids, which are believed to be the phototrophic ancestors of the parasitic apicomplexans. Molecular pathways involved in Alveolata host–pathogen interactions, epigenetic regulation and metabolism in parasite development remain to be fully understood. Peptidylarginine deiminases (PADs) are a phylogenetically conserved enzyme family which causes post-translational protein deimination, affecting protein function through the conversion of arginine to citrulline in a wide range of target proteins, contributing to protein moonlighting in physiological and pathological processes. The identification of deiminated protein targets in alveolate parasites may therefore provide novel insight into pathogen survival and host-pathogen interactions. The current study assessed PAD homologues and deiminated protein profiles of two alveolate parasites, Piridium sociabile (Chromerida) and Merocystis kathae (Apicomplexa). Histological analysis verified strong cytoplasmic PAD expression in both Alveolates, detected deiminated proteins in nuclear and cytoplasmic compartments of the alveolate parasites and verified the presence of citrullinated histone H3 in Alveolata nucleus, indicating roles in epigenetic regulation. Histone H3 citrullination was also found significantly elevated in the host tissue, indicative of neutrophil extracellular trap formation, a host-defence mechanism against a range of pathogens, particularly those that are too large for phagocytosis. Proteomic analysis of deiminated proteins from both Alveolata identified GO and KEGG pathways strongly relating to metabolic and genetic regulation, with some species-specific differences between the apicomplexan and the chromerid. Our findings provide novel insights into roles for the conserved PAD/ADI enzyme family in the regulation of metabolic and epigenetic pathways in alveolate parasites, possibly also relating to their life cycle and host–pathogen interactions

Peptidylarginine Deiminase (PAD) and Post-Translational Protein Deimination—Novel Insights into Alveolata Metabolism, Epigenetic Regulation and Host–Pathogen Interactions

The alveolates (Superphylum Alveolata) comprise a group of primarily single-celled eukaryotes that have adopted extremely diverse modes of nutrition, such as predation, photoautotrophy and parasitism. The alveolates consists of several major phyla including the apicomplexans, a large group of unicellular, spore forming obligate intracellular parasites, and chromerids, which are believed to be the phototrophic ancestors of the parasitic apicomplexans. Molecular pathways involved in Alveolata host–pathogen interactions, epigenetic regulation and metabolism in parasite development remain to be fully understood. Peptidylarginine deiminases (PADs) are a phylogenetically conserved enzyme family which causes post-translational protein deimination, affecting protein function through the conversion of arginine to citrulline in a wide range of target proteins, contributing to protein moonlighting in physiological and pathological processes. The identification of deiminated protein targets in alveolate parasites may therefore provide novel insight into pathogen survival and host-pathogen interactions. The current study assessed PAD homologues and deiminated protein profiles of two alveolate parasites, Piridium sociabile (Chromerida) and Merocystis kathae (Apicomplexa). Histological analysis verified strong cytoplasmic PAD expression in both Alveolates, detected deiminated proteins in nuclear and cytoplasmic compartments of the alveolate parasites and verified the presence of citrullinated histone H3 in Alveolata nucleus, indicating roles in epigenetic regulation. Histone H3 citrullination was also found significantly elevated in the host tissue, indicative of neutrophil extracellular trap formation, a host-defence mechanism against a range of pathogens, particularly those that are too large for phagocytosis. Proteomic analysis of deiminated proteins from both Alveolata identified GO and KEGG pathways strongly relating to metabolic and genetic regulation, with some species-specific differences between the apicomplexan and the chromerid. Our findings provide novel insights into roles for the conserved PAD/ADI enzyme family in the regulation of metabolic and epigenetic pathways in alveolate parasites, possibly also relating to their life cycle and host–pathogen interactions

Is an Apicomplexan Parasite Responsible for the Collapse of the Iceland Scallop (Chlamys islandica) Stock?

Due to the total and unexpected collapse of the Iceland scallop, Chlamys islandica, stocks around Iceland during the 2000s, a commercial fishing ban has been imposed on this valuable resource since 2003. Following the initial identification of an apicomplexan parasite in the scallops, a long-term surveillance program was established to evaluate the effect of the parasite on the population. The infections were highly prevalent in all shell sizes throughout the study. However, the parasite only impacts mature scallops where they cause severe macroscopic changes, characterized by an extensively diminished and abnormally coloured adductor muscle. A highly significant relationship was observed between infection intensity and gonad and adductor muscle indices. The first four years of the study, were characterized by high infection intensity and very poor condition of the adductor muscle and gonads, whilst during subsequent years, infections gradually decreased and the condition of the scallops improved. Histopathological changes were restricted to the presence of apicomplexan zoites which were widely distributed, causing varying degrees of pathology in all organs. In heavy infections, muscular and connective tissues were totally necrotized, destroying significant parts of numerous organs, especially the adductor muscle, digestive gland and gonads. The progression of the disease was in good synchrony with the mortality rates and the subsequent decline observed in the scallop stock and recruitment indices. Our findings strongly suggest that the apicomplexan parasite played a major role in the collapse of the Iceland scallop stock in Breidafjordur. In addition to causing mortality, the infections significantly impact gonad development which contributes further to the collapse of the stock in the form of lower larval recruitment. Furthermore, compelling evidence exists that this apicomplexan pathogen is causing serious disease outbreaks in other scallop populations. Similar abnormal adductor muscles and the parasite itself have been identified or observed in association with other mass mortality events in several different scallop species and commercial stocks in the northern hemisphere

Vísindadagur Keldna 2023

Tilraunastöð Háskóla Íslands í meinafræði að Keldum fagnar sjötíu og fimm ára starfsafmæli í ár. Af því tilefni er ráðstefna/vísindadagur sem fer fram 19. apríl 2023 á bókasafni Tilraunastöðvarinnar. Tilraunastöðin starfar fyrst og fremst sem rannsóknastofa á háskólastigi og er eini vettvangurinn í landinu þar sem rannsóknir, skimunarverkefni og greiningar fara fram á dýrasjúkdómum á mörgum fræðasviðum. Rannsakaðir eru sjúkdómar og smitefni í flestum spendýrategundum Íslands og allmörgum fugla-, fisk- og lindýrategundum. Tilraunastöðin er í nánu samstarfi við atvinnulífið, má þar nefna landbúnað, fiskeldi, matvælaframleiðslu og líftækniiðnað. Starfið er rótgróið og gott dæmi um samlegðaráhrif vísindastarfs og atvinnulífs. Vel hefur gengið að vinna með þær sérstöku aðstæður sem eru á Íslandi varðandi dýrasjúkdóma og greiningar á þeim. Vísindadagurinn hefur fest sig í sessi sem vettvangur fyrir kynningu á starfsemi og fræðasviðum Keldna. Ráðstefnan er allan daginn og aðgangur er öllum heimill að kostnaðarlausu. Nú er vísindadagurinn með almennara sniði en oft áður og er m.a. ætlaður sem samráðsvettvangur hagaðila sem starfa í lífvísinda- og dýraheilbrigðisfræðum. Þeir fyrirlesarar sem sjá um fræðsluna eru sérfræðingar á Keldum og aðrir sérfræðingar frá háskólum og vísindastofnunum innanlands og erlendis. Einnig verða kynnt veggspjöld sem greina frá ýmsum verkefnum á Keldum. Anna Karen Sigurðardóttir, Ásthildur Erlingsdóttir og Birkir Þór Bragason eru í vísindanefnd sem sér um undirbúning og skipulag. Ég færi þeim mínar bestu þakkir fyrir spennandi og fjölbreytta dagsskrá. Mínar bestu árnaðaróskir til núverandi og fyrrverandi Keldnastarfsmanna og hamingjuóskir með árangur síðastliðna áratugi. Framlag þeirra hefur gert Keldur að þeirri framsýnu rannsóknastofnun dýrasjúkdóma sem hún er í dag. Á Keldum er fagleg forysta á ýmsum fræðasviðum og mikil þekking og reynsla. Ég óska Tilraunastöðinni og starfsmönnum hennar áframhaldandi velgengni og velfarnaðar í framtíðinni. Sigurður Ingvarsson, forstöðumaður og prófesso

Host responses to infections.

<p>Host responses to the apicomplexan infections. (A) An isolation of a cluster of apicomplexan zoites with fibroblast like cells (arrow). (B) Repairing of scallop foot where fibromuscular tissue is substituted by fibroblast like cells (*). NM = Normal muscle; FM = Fibromuscular tissue.</p

Effect of apicomplexan infections on the scallop condition.

<p>(A) Adductor muscles from three mature scallops. The first on the left is from 7.8 cm scallop which has severe macroscopic changes (grade 3; MI = 1.4), it is brownish coloured and greatly diminished and extensively infected while the first on the right is from 7.2 cm healthy looking one with firm and light coloured adductor muscle (MI = 2.5) which had a mild apicomplexan infection. The one in the middle is from a 7.5 cm scallop with grade 1 macroscopic changes (MI = 1.9). (B) The relationship of the MI and the grades of infections from all mature scallops examined (N = 1218). The MI deceases significantly with increasing grades of infection (p < 0.0001 between all grades). (C) The relationship of the GI and the grades of infections from all mature scallops sampled in the spring (red boxes; N = 297) and autumn (blue boxes; N = 794). A reduction in the GI is apparent, especially in the spring (red double arrow line). Note that in spring the GI should be much higher as these shells should be close to full maturity. However, scallops with grade 5 infections is not significantly different between autumn and spring. Furthermore, the GI for grade 5 spring scallops is significantly lower than the one for grade 1–3 autumn scallops (blue/red double arrow line). (D) The relationship of the GI and the grades of macroscopic changes observed in adductor muscles. The GI significantly decreases with severity of the macroscopic changes. (E and F) Comparison of the gonad weigh of 7.5 cm scallops caught in autumn (E) and spring (F) in 1988–1990 [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0144685#pone.0144685.ref015" target="_blank">15</a>] and 2003–2014 (extrapolated to 7.5 cm). The whole and broken horizontal red lines represent the normal mean range of gonad weight observed by Thorarinsdottir [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0144685#pone.0144685.ref015" target="_blank">15</a>] from a healthy population of scallops in 1988–1990. (E) Scallops sampled in autumn (N = 794). The gonad weight of scallops from 2005 and 2006 is greatly reduced but from 2007 their weigh is similar to those observed in 1988–1990. (F) Scallops sampled in spring (N = 297). The gonad weight of scallops from 2005 and 2006 is greatly reduced. In 2007, their weigh is approaching normal and from that time their weight is similar to those in 1988–1990. (G) Macroscopic changes observed in the gonad caught in the spring and (H) healthy looking gonad caught at the same time. *The notches on the boxplots provide an approximate 95% test of the null hypothesis that the true medians are equal: if the notches do not overlap, the medians could be described as statistically significant.</p