[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to examine the role of basic psychological need satisfaction as a potential
mediator of the relationship between health-enhancing physical activity (HEPA) and well-being.
Participants (N = 201) were young adults who recalled their HEPA behavior, experiences of psychological
need satisfaction, and levels of well-being across multiple indicators using a cross-sectional
design targeting the previous day. Results from path analysis demonstrated that effort put forth in
HEPA activities, as opposed to frequency or duration of HEPA, predicted well-being. Further, psychological
needs satisfaction mediated between 10% and 44% of the HEPA-Effort - well-being relationship.
Overall, these findings lend credence to the notion that effortful investment is associated with well-being
when engaged in HEPA, and that the satisfaction of basic psychological needs may act as a salient
explanatory mechanism partially accounting for that relationship.
Full-text · Article · Dec 2012 · Mental Health and Physical Activity
[Show abstract][Hide abstract] ABSTRACT: Objectives
The purpose of this study was to examine the effects of different scoring protocols used with instruments designed to assess motivation in line with Organismic Integration Theory (OIT; Deci & Ryan, 2002).DesignThis study used non-probability based sampling within a cross-sectional (survey) design.Methods
Participants across four samples (N's ranged from 236 to 1200) completed either (a) the Behavioral Regulation in Exercise Questionnaire (BREQ), (b) the BREQ-2, or (c) the BREQ-2R in conjunction with a self-report assessment of physical activity behavior.ResultsParticipants endorsed more self-determined than controlled motives for physical activity. Identified regulation was the dominant correlate of more frequent physical activity behavior. The link between external regulation and physical activity was consistently weak. Multiple regression analyses revealed identified regulation was the strongest predictor of physical activity compared with other motives. Regression models using omnibus scoring protocols accounted for less variance in physical activity behavior in contrast to an item-aggregation scoring protocol.Conclusions
Identified regulation may be a key source of physical activity motivation in adults. The scoring protocol used with OIT-based instruments represents an important consideration for advancing physical activity research.
Full-text · Article · Sep 2012 · Psychology of Sport and Exercise
[Show abstract][Hide abstract] ABSTRACT: Objectives: The purpose of this investigation was to test associations between the fulfillment of basic psychological needs and two dimensions of psychological well-being using (a) an additive model and (b) a balanced model. Design: This study employed a non-probability based sampling and a cross-sectional design. Methods: Collegiate volleyball players (N = 219; n(females) = 127) completed a battery of self-report instruments. Results: Aligned within Basic Psychological Needs Theory (Deci & Ryan, 2002) and study hypotheses (Sheldon & Niemiec, 2006), results demonstrated that basic psychological need fulfillment was associated with psychological well-being in the context of volleyball (R(adj)(2) ranged from 0.20 to 0.35). Balanced psychological need fulfillment was generally predictive, albeit minimally, of well-being indices beyond the contributions made by perceived competence, autonomy and relatedness. Conclusions: This investigation highlights the need for further study of BPNT in the realm of sport including assessments of balanced need satisfaction on markers of well-being.
Full-text · Article · Sep 2011 · Psychology of Sport and Exercise
[Show abstract][Hide abstract] ABSTRACT: Kong, L., Tull, R., Holtz, C.T., Montello, P.M., Sakowski, R., Nairn, C.J., and Merkle, S.A. 2011. Application of airlift bioreactors for highly efficient genetic transformation of American chestnut. In: Proceedings of the 31st Southern Forest Tree Improvement Conference, June 13-16, Biloxi, MS, p.102.
[Show abstract][Hide abstract] ABSTRACT: Merkle, S.A., Kong, L., Tull, R., Andrade, G., Montello, P.M., Holtz, C.T., Sakowski, R., and Nairn, C.J. 2011. Scaling-up Transgenic American Chestnut Somatic Seedling Production for the Forest Health Initiative. In: Proceedings of the 31st Southern Forest Tree Improvement Conference, June 13-16, Biloxi, MS, pp. 58-60.
[Show abstract][Hide abstract] ABSTRACT: Onlangs is de DNA-sequentie van het genoom van Cladosporium fulvum bepaald. Het voornaamste doel daarvan is de identificatie en karakterisering van nieuwe effectors.
[Show abstract][Hide abstract] ABSTRACT: In order to facilitate infection, fungal pathogens produce various types of secreted proteases likely to target and perturb important plant proteins that are involved in controlling basal defense. In addition, they secrete several protease inhibitors such as Avr9 of Cladosporium fulvum that, based on its structure, is predicted to be a carboxy peptidase inhibitor. Protease inhibitors are potentially able to deactivate or detoxify host target proteases and, therefore, might play an important role during infection. In this study we are investigating the role of C. fulvum protease and protease inhibitors in disease establishment by using both functional genomics and biochemical approaches. We mined the genome of C. fulvum and found numerous proteases and protease inhibitors of which many are secreted. Expression analyses of these genes were performed using RNA extracted from fungal mycelium grown in vitro on liquid media under different conditions as well as from inoculated susceptible tomato plants. Interestingly, many of these genes are highly expressed only in vitro and/or in planta and based on their expression profiles we selected a number of candidates for further functional analyses. We will generate knock‐out mutants of the selected proteases and protease inhibitors to identify their role in virulence. In addition, biochemical approaches will be used to pull‐down the host target proteins of some presumably important candidate proteins such as for example the Avr9 protein
[Show abstract][Hide abstract] ABSTRACT: De natuur levert op een haast onmerkbare manier allerlei diensten aan de mens. Zo beschermen duinen ons land bijvoorbeeld tegen overstromingen en slaan bossen CO2 op. In Nederland zijn er diverse kansen om deze door de natuur geleverde diensten, of wel ecosysteemdiensten, te benutten. Om de discussie over ecosysteemdiensten, en de kansen die zij bieden, te stimuleren en te verdiepen heeft het Planbureau voor de Leefomgeving (PBL) samen met Wageningen UR een brochure uitgebracht. Deze biedt ook enkele aanknopingspunten voor het beleid.
[Show abstract][Hide abstract] ABSTRACT: Most fungal effectors characterized so far are species-specific and facilitate virulence on a particular host plant. During infection of its host tomato, Cladosporium fulvum secretes effectors that function as virulence factors in the absence of cognate Cf resistance proteins and induce effector-triggered immunity in their presence. Here we show that homologs of the C. fulvum Avr4 and Ecp2 effectors are present in other pathogenic fungi of the Dothideomycete class, including Mycosphaerella fijiensis, the causal agent of black Sigatoka disease of banana. We demonstrate that the Avr4 homolog of M. fijiensis is a functional ortholog of C. fulvum Avr4 that protects fungal cell walls against hydrolysis by plant chitinases through binding to chitin and, despite the low overall sequence homology, triggers a Cf-4-mediated hypersensitive response (HR) in tomato. Furthermore, three homologs of C. fulvum Ecp2 are found in M. fijiensis, one of which induces different levels of necrosis or HR in tomato lines that lack or contain a putative cognate Cf-Ecp2 protein, respectively. In contrast to Avr4, which acts as a defensive virulence factor, M. fijiensis Ecp2 likely promotes virulence by interacting with a putative host target causing host cell necrosis, whereas Cf-Ecp2 could possibly guard the virulence target of Ecp2 and trigger a Cf-Ecp2-mediated HR. Overall our data suggest that Avr4 and Ecp2 represent core effectors that are collectively recognized by single cognate Cf-proteins. Transfer of these Cf genes to plant species that are attacked by fungi containing these cognate core effectors provides unique ways for breeding disease-resistant crops
[Show abstract][Hide abstract] ABSTRACT: Tot nu toe werden effectoreiwitten van schimmels beschouwd als soortspecifiek en homologen van Cladosporium fulvum effectors werden nooit eerder aangetoond in andere schimmelsoorten. Nu is er bewijs gevonden voor het bestaan van homologe C. fulvum effectors in soorten van Dothideomycetes die pathogeen zijn op ver verwante monocotyle en dicotyle plantensoorten.
[Show abstract][Hide abstract] ABSTRACT: Reducing decomposition and mineralization of organic matter by increasing groundwater levels is a common approach to reduce plant nutrient availability in many peat meadow restoration projects. The soil community is the main driver of these processes, but how community composition is affected by peat meadow restoration is largely unknown. Furthermore, it is unclear whether restoration induced changes could lead to altered decomposition and mineralization rates. We determined soil community composition in restored peat meadows with different groundwater levels and soil pH. This composition was subsequently used in food web model calculations of C and N mineralization rates to assess whether differences in soil community composition may have contributed to differences in decomposition and mineralization rates observed between these meadows. Community composition of micro-organisms, Collembola and Enchytraeidae differed considerably between meadows and were correlated with differences in groundwater levels and soil pH. Collembolan and enchytraeid species from wet and neutral environments were more abundant at meadows with higher groundwater levels. Lower fungal to bacterial PLFA ratios and higher numbers of protozoa indicated an increased importance of the bacterial part of the food web at meadows with higher groundwater levels. Food web model calculations suggested that the observed changes in community composition would lead to higher rates of C and N mineralization at meadows with high groundwater levels. Results from modeling were consistent with field measurements of C mineralization, but not with measurements of N mineralization
Full-text · Article · Aug 2009 · Soil Biology and Biochemistry
[Show abstract][Hide abstract] ABSTRACT: De bacterie Xanthomonas fragariae veroorzaakt de bacteriebladvlekkenziekte in aardbei. De bacteriebladvlekkenziekte is een quarantaineziekte. Wanneer de ziekte voorkomt worden maatregelen getroffen om verspreiding te voorkomen. Het aangetaste gewas wordt doodgespoten met een herbicide en verbrand, of de planten worden na rooien gekneusd en ondergewerkt om vertering te bevorderen. In dit onderzoek werd onderzocht hoelang X. fragariae onder Nederlandse omstandigheden kan overleven op ondergewerkte gewasresten