Pathogenicity of Swedish isolates of Phytophthora quercina to Quercus robur in two different soils

Several studies have demonstrated the involvement of soil-borne Phytophthora species, especially Phytophthora quercina , in European oak decline. However, knowledge about the pathogenicity of P. quercina in natural forest soils is limited. The short-term effects of two south-Swedish isolates of P. quercina on root vitality of Quercus robur seedlings grown in two different soils, one high pH, nutrient-rich peat-sand mixture and one acid, nitrogen-rich but otherwise nutrient-poor forest soil are described. Pathogenicity of P. quercina was tested using a soil infestation method under a restricted mesic water regime without prolonged flooding of the seedlings. There was a significant difference in dead fine-root length between control seedlings and seedlings grown in soil infested with P. quercina . Trends were similar for both soil types and isolates, but there was a higher percentage of fine-root die-back and more severe damage on coarse roots in the acid forest soil. No effects on above-ground growth or leaf nutrient concentration between control seedlings and infected seedlings were found. The results confirm the pathogenicity of south-Swedish isolates of P. quercina in acid forest soils under restricted water availability. Stress-induced susceptibility of the seedlings and/or increased aggressiveness of the pathogen in the forest soil are discussed as key factors to explain the difference in root die-back between soil types

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

Portfoliometodiken i NO-ämnen på gymnasiet

I samband med läroplanens tydliga fokus på Lära elever att Lära har portfoliometodiken under 90-talet vuxit sig stark som pedagogisk metod i Sverige. Syftet med denna studie var att teoretiskt undersöka om portfoliometodiken kan användas inom NO-ämnena på gymnasienivå. Metoden har hittills främst har använts inom skolans lägre stadier men i princip inte alls i skolans NO-undervisning på gymnasiet. Mål för övergång till denna metodik är att skapa bättre inlärningsmöjligheter för eleverna samt att stimulera dem till att reflektera över sitt eget lärande. Studien är uppbyggd av tre olika faser: a) inhämtande av bakgrundsinformation genom intervjuer, b) utformande av en konkret elevportfolio baserat på utfallet i intervjuerna samt c) teoretisk utvärdering av elevportfolion och portfoliometodiken i NO –undervisningen. Jag använde den semistrukturerade intervjuformen och jag intervjuade totalt 5 gymnasielärare. Resultaten antyder att portfoliometodiken bör vara väl lämpad för att använda i gymnasieskolans NO-ämnen. Det här producerade utkastet till Elevportfolio innehåller delar som bör gynna elevens metakognition och elevens möjligheter till inlärning stimuleras. Det vore önskvärt med ett nästa steg där ett portfolioarbetes implementering studeras. Stor vikt bör läggas vid tidsaspekten i en ny undersökning då denna studie i likhet med flera andra påtalar att tiden är en stötesten i portfoliometodiken

Portfoliometodiken i NO-ämnen på gymnasiet

I samband med läroplanens tydliga fokus på Lära elever att Lära har portfoliometodiken under 90-talet vuxit sig stark som pedagogisk metod i Sverige. Syftet med denna studie var att teoretiskt undersöka om portfoliometodiken kan användas inom NO-ämnena på gymnasienivå. Metoden har hittills främst har använts inom skolans lägre stadier men i princip inte alls i skolans NO-undervisning på gymnasiet. Mål för övergång till denna metodik är att skapa bättre inlärningsmöjligheter för eleverna samt att stimulera dem till att reflektera över sitt eget lärande. Studien är uppbyggd av tre olika faser: a) inhämtande av bakgrundsinformation genom intervjuer, b) utformande av en konkret elevportfolio baserat på utfallet i intervjuerna samt c) teoretisk utvärdering av elevportfolion och portfoliometodiken i NO –undervisningen. Jag använde den semistrukturerade intervjuformen och jag intervjuade totalt 5 gymnasielärare. Resultaten antyder att portfoliometodiken bör vara väl lämpad för att använda i gymnasieskolans NO-ämnen. Det här producerade utkastet till Elevportfolio innehåller delar som bör gynna elevens metakognition och elevens möjligheter till inlärning stimuleras. Det vore önskvärt med ett nästa steg där ett portfolioarbetes implementering studeras. Stor vikt bör läggas vid tidsaspekten i en ny undersökning då denna studie i likhet med flera andra påtalar att tiden är en stötesten i portfoliometodiken

Can Phytophthora quercina have a negative impact on mature pedunculate oaks under field conditions?

Ten oak stands in southern Sweden were investigated to evaluate the impact of the root pathogen Phytophthora quercina on mature oaks under field conditions. Phytophthora quercina was present in five of the stands, while the other five stands were used as controls to verify the effect of the pathogen. In each stand, a healthy, a moderately declining and a severely declining tree were sampled. Fine-root length and nutrient status of each tree were analyzed, and the chemistry of the soil surrounding each tree was determined. The results showed that P. quercina can cause substantial reductions in the fine-root length of mature trees under natural conditions. The impact of the pathogen varied depending on tree vitality and season, being most pronounced for declining trees after an unusually dry summer. Despite the significant reduction in live fine-root length of declining trees in Phytophthora-infested stands, no consistent effects were found on the nutrient status of trees. Based on the significant impact of the pathogen on the fine-root systems of declining trees, we suggest that P. quercina contribute to oak decline in southern Sweden at the sites where it is present. No explanation is currently available for the decline of trees in non-infested stands, but the lack of symptoms of root damage indicate, together with the extensive root growth of declining trees, that root pathogens are not involved in the decline at these sites.Phtytophthora quercina peut-il avoir un effet négatif sur les chênes pédonculés adultes en conditions de terrain ?. Dix peuplements de chêne du sud de la Suède ont été examinés pour évaluer l'impact du pathogène racinaire Phytophthora quercina sur des chênes adultes en conditions de terrain. P. quercina était présent dans cinq peuplements, les cinq autres furent utilisés comme témoin des effets du pathogène. Dans chaque peuplement, un arbre sain, un arbre modérément dépérissant et un arbre très dépérissant ont été échantillonnés. La longueur des fines racines et le statut minéral de chaque arbre, ainsi que les caractéristiques chimiques du sol alentour ont été déterminés. Les résultats ont montré que P. quercina peut causer des réductions substantielles de la longueur des fines racines des arbres adultes dans les conditions de terrain. L'impact du pathogène varie selon la vitalité de l'arbre et la saison, avec des effets plus prononcés après un été particulièrement sec pour les arbres dépérissants. Malgré la réduction significative de la longueur des fines racines chez les arbres dépérissants dans les peuplements infectés par P. quercina, aucun réel effet n'a été trouvé sur le statut minéral des arbres. En nous appuyant sur l'impact significatif au niveau des fines racines, nous suggérons que P. quercina contribue au déclin des chênes dans le sud de la Suède

Communication, cooperation and developmentcommondenominator to workmotivation

Arbetsmotivation är en stor och viktig drivkraft för den pedagogiska utvecklingen på en arbetsplats I vår empiri har vi undersökt arbetsmotivation som är ett oerhört intressant men komplext område. Syftet med vår empiri är att upplysa, synliggöra faktorer och metoder samt vilka synsätt olika organisationer har internt av begreppet arbetsmotivation. Vår forskningsfråga lyder; ”Hur främjar ledare och organisationer arbetsmotivarion för medarbetaren?” Empirin är genomförd genom en kvalitativ forskningsmetod respondenterna bestod av ledare med medarbetaransvar inom omsorgssektorn och i värdeskapande organistioner. I empirin fann vi tre nyckelkomponenter vilka samtliga ledare ansåg vara betydande för att främja medarbetarnas arbetsmotivation, kommunikation, samverkan och utveckling.

Relationships between health of Quercus robur, occurrence of Phytophthora species and site conditions in southern Sweden

The effect of Phytophthora species, soil chemistry, precipitation and temperature on the vitality of oak was evaluated in 32 oak stands in southern Sweden. In addition, the relationship between the occurrence of Phytophthora species and soil conditions was determined. The results showed that there was a weak association between the presence of P. quercina, the most frequently recovered Phytophthora species in southern Sweden, and the vitality of the oak stands (determined from estimates of crown defoliation of individual trees). The pathogens occurred more frequently in clayey and loamy soils that were less acidic and which had higher base saturation. However, they were found in all but the most acidic soils (pH < 3.5). In stands where Phytophthora species were not present, positive correlations between the average crown defoliation and proportion of damaged trees with average summer precipitation and average annual precipitation were found. There were no significant differences in soil chemistry between healthy and declining stands included in this study, and no significant correlations were found between any soil parameter and crown vitality. Based on the results from these 32 oak stands, it is likely that the decline of oaks in southern Sweden can be attributed to several different site-specific factors, such as infection by P. quercina or unusual weather events, which interact with a number of biotic and abiotic factors, leading to oak decline

A comparative study of two methods for determination of pH, exchangeable base cations, and aluminum

The ability to compare soil chemical data achieved by different chemical extraction methods is a necessity for an efficient long-term monitoring of soils and for comparisons of results from regional soil surveys with differing standard methods. This study compares two common, methods for analysis of soil chemical properties, the combination of soil extraction in 1.0 M NH4Cl and 1.0 M KCl and the single extraction method using 0.1 M BaCl2. Results show that the two methods do not differ in extraction capability with regard to pH and exchangeable calcium (Ca) and magnesium (Mg). However, there is less agreement in extraction capability with regard. to potassium (K), sodium (Na), and aluminum (Al). For these elements, BaCl2 is less efficient than NH4Cl and KCl. Despite the differences in extraction capability between BaCl2 and KCl/NH4Cl, regression analyses showed that the methods are well correlated (high regression coefficients for all, elements). Thus, transformation of data achieved by one method to estimated values of the other method are possible. Results from this study may be an important tool for comparisons of mineral soil data achieved by the two methods

Anaplerosis via pyruvate carboxylase is required for the fuel-induced rise in the ATP:ADP ratio in rat pancreatic islets.

AIMS/HYPOTHESIS: The molecular mechanisms of insulin release are only partially known. Among putative factors for coupling glucose metabolism to insulin secretion, anaplerosis has lately received strong support. The anaplerotic enzyme pyruvate carboxylase is highly expressed in beta cells, and anaplerosis influences insulin secretion in beta cells. By inhibiting pyruvate carboxylase in rat islets, we aimed to clarify the hitherto unknown metabolic events underlying anaplerotic regulation of insulin secretion. METHODS: Phenylacetic acid (5 mmol/l) was used to inhibit pyruvate carboxylase in isolated rat islets, which were then assessed for insulin secretion, fuel oxidation, ATP:ADP ratio, respiration, mitochondrial membrane potential, exocytosis and ATP-sensitive K(+) channel (K(ATP)-channel) conductance. RESULTS: We found that the glucose-provoked rise in ATP:ADP ratio was suppressed by inhibition of pyruvate carboxylase. In contrast, fuel oxidation, respiration and mitochondrial membrane potential, as well as Ca(2+)-induced exocytosis and K(ATP)-channel conductance in single cells, were unaffected. Insulin secretion induced by alpha-ketoisocaproic acid was suppressed, whereas methyl-succinate-stimulated secretion remained unchanged. Perifusion of rat islets revealed that inhibition of anaplerosis decreased both the second phase of insulin secretion, during which K(ATP)-independent actions of fuel secretagogues are operational, as well as the first and K(ATP)-dependent phase. CONCLUSIONS/INTERPRETATION: Our results are consistent with the concept that anaplerosis via pyruvate carboxylase determines pyruvate cycling, which has previously been shown to correlate with glucose responsiveness in clonal beta cells. These processes, controlled by pyruvate carboxylase, seem crucial for generation of an appropriate ATP:ADP ratio, which may regulate both phases of fuel-induced insulin secretion