228 research outputs found

    Bacterial endophyte communities in the foliage of coast redwood and giant sequoia

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    The endophytic bacterial microbiome, with an emerging role in plant nutrient acquisition and stress tolerance, is much less studied in natural plant populations than in agricultural crops. In a previous study, we found consistent associations between trees in the pine family and acetic acid bacteria (AAB) occurring at high relative abundance inside their needles. Our objective here was to determine if that pattern may be general to conifers, or alternatively, is more likely restricted to pines, or conifers growing in nutrient limited and exposed environments. We used 16S rRNA pyrosequencing to characterize the foliar endophyte communities of two conifers in the Cupressaceae family: Two coast redwood (Sequoia sempervirens) populations and one giant sequoia (Sequoiadendron giganteum) population were sampled. Similar to the pines, the endophyte communities of the giant trees were dominated by Proteobacteria, Firmicutes, Acidobacteria, and Actinobacteria. However, although some major OTUs occurred at a high relative abundance of 10-40% in multiple samples, no specific group of bacteria dominated the endophyte community to the extent previously observed in high-elevation pines. Several of the dominating bacterial groups in the coast redwood and giant sequoia foliage (e.g. Bacillus, Burkholderia, Actinomycetes) are known for disease- and pest suppression, raising the possibility that the endophytic microbiome protects the giant trees against biotic stress. Many of the most common and abundant OTUs in our dataset were most similar to 16S rRNA sequences from bacteria isolated from lichens or arctic plants. For example, an OTU belonging to the uncultured Rhizobiales LAR1 lineage, which is commonly associated with lichens, was observed at high relative abundance in many of the coast redwood samples. The taxa shared between the giant trees, arctic plants, and lichens may be part of a broadly defined endophyte microbiome common to temperate, boreal, and tundra ecosystems

    Problem Solving Thinking of Adolescent Drug Abusers: Developmental Considerations

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    Psycholog

    Cytokinin response factor 6 represses cytokinin-associated genes during oxidative stress

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    Cytokinin is a phytohormone that is well known for its roles in numerous plant growth and developmental processes, yet it has also been linked to abiotic stress response in a less defined manner. Arabidopsis (Arabidopsis thaliana) Cytokinin Response Factor 6 (CRF6) is a cytokinin-responsive AP2/ERF-family transcription factor that, through the cytokinin signaling pathway, plays a key role in the inhibition of dark-induced senescence. CRF6 expression is also induced by oxidative stress, and here we show a novel function for CRF6 in relation to oxidative stress and identify downstream transcriptional targets of CRF6 that are repressed in response to oxidative stress. Analysis of transcriptomic changes in wild-type and crf6 mutant plants treated with H2O2 identified CRF6-dependent differentially expressed transcripts, many of which were repressed rather than induced. Moreover, many repressed genes also show decreased expression in 35S:CRF6 overexpressing plants. Together, these findings suggest that CRF6 functions largely as a transcriptional repressor. Interestingly, among the H2O2 repressed CRF6-dependent transcripts was a set of five genes associated with cytokinin processes: (signaling) ARR6, ARR9, ARR11, (biosynthesis) LOG7, and (transport) ABCG14. We have examined mutants of these cytokinin-associated target genes to reveal novel connections to oxidative stress. Further examination of CRF6-DNA interactions indicated that CRF6 may regulate its targets both directly and indirectly. Together, this shows that CRF6 functions during oxidative stress as a negative regulator to control this cytokinin-associated module of CRF6-dependent genes and establishes a novel connection between cytokinin and oxidative stress response

    Grassland Root Communities: Species Distributions and How They Are Linked to Aboveground Abundance.

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    There is little comprehensive information on the distribution of root systems among coexisting species, despite the expected importance of those distributions in determining the composition and diversity of plant communities. This gap in knowledge is particularly acute for grasslands, which possess large numbers of species with morphologically indistinguishable roots. In this study we adapted a molecular method, fluorescent fragment length polymorphism, to identify root fragments and determine species root distributions in two grasslands in Yellowstone National Park. Aboveground biomass was measured and soil cores (2 cm diam) were collected to 40 cm and 90 cm in an upland, dry grassland and a mesic, slope-bottom grassland, respectively, at peak foliar expansion. Cores were subdivided and species that occurred in each 10 cm interval were identified. The results indicated that the average number of species in 10 cm intervals (31 cm3) throughout the sampled soil profile was 3.9 and 2.8 at a dry and a mesic grassland, respectively. By contrast, average species number per 0.5 m2 determined by the presence of shoot material was 6.7 and 14.1 at dry and mesic sites, respectively. There was no relationship between soil depth and number of species per 10 cm interval in either grassland, despite the exponential decline of root biomass with soil depth at both sites. There also was no relationship between root frequency (i.e., the percentage of samples in which a species occurred) and soil depth for the vast majority of species at both sites. The preponderance of species were distributed throughout the soil profile at both sites. Assembly analyses indicated that species root occurrences were randomly assorted in all soil intervals at both sites, with the exception that F. idahoensis segregated from A. tridentata and P. spicata in 10-20 cm soil at the dry grassland. Root frequency throughout the entire sampled soil profile was positively associated with shoot biomass among species. Together these results indicated the importance of large, well proliferated root systems in establishing aboveground dominance. The findings suggest that spatial belowground segregation of species probably plays a minor role in fostering resource partitioning and species coexistence in these YNP grasslands

    Academic performance as a perceived function of ability and effort

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    Subjects made predictions of the grade point averages of hypothetical students who varied over complete continua of scholastic ability and effort. Subjects in Study 1 made their predictions on the implicit assumption that target students were drawn from a student body chosen via selective admissions criteria. Study 2 subjects assumed that the ability range was one resulting from a “first-come, first-served” open-admissions policy. Although the ability assumption inductions, as intended, led to performance level predictions that were differently dispersed, the basic patterns of subjects' predictions were essentially the same in both studies: For the overwhelming majority of subjects, ability and effort were perceived to affect scholastic performance additively rather than multiplicatively, thus contradicting the suggestions of previous theory. In addition, students with high ability were anticipated to perform reasonably well even when exerting practically no effort. Theoretical interpretations and practical implications of these results are introduced and discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45372/1/11031_2005_Article_BF01650602.pd

    A mixed methods approach to advance the understanding of physical activity behaviour during pregnancy

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    An active pregnancy encompasses benefits that apply to both mother and baby. However, before investing resources in interventions aimed at changing or supporting expectant mothers’ physical activity behaviours, it is necessary to have a greater fundamental understanding of the modifiable factors influencing women’s decisions during this time. Therefore, the main purpose of this study was to investigate the socio-cognitive determinants of physical activity during pregnancy. A mixed methods research approach using a multiphase design framed by the Theory of Planned Behaviour (TPB; Ajzen, 1991, Organizational Behavior and Human Decision Processes, 50, 179-211) guided the investigation. Following ethical approval and permission to carry out the study, participants were recruited from randomly selected antenatal clinics in the East Kent region of England. Application of the TPB required both qualitative and quantitative cross-sectional data to be collected. Study One (n = 18) involved the elicitation of pregnant women’s beliefs towards being physically active. The modal salient behavioural, normative and control beliefs were used to inform the development of a TPB questionnaire which was implemented during the next phase of the investigation. Study Two (n = 78) examined the predictive utility of the TPB in explaining pregnant women’s physical activity intentions and behaviour and scrutinised the role of past behaviour within this context. Finally, Study Three (n = 10) comprised semi-structured interviews involving community midwives. Meta-inferences maintained the function of improving the validity of the study and advancing the overall aim of the research project. Specifically, triangulation was used to ascertain convergence, corroboration, and correspondence of findings between studies. Whilst results of the individual studies hold merit, meta-inferences point towards the development of three main themes: (1) pregnant women lack access to the necessary information that would allow them to make informed decisions regarding their engagement in physical activities; (2) a co-ordinated effort involving interprofessional collaboration is required to support pregnant women in overcoming barriers associated with regular physical activity participation; and (3) profiling pregnant women according to motivation and behaviour status could serve as a useful and manageable starting point for intervening to produce positive changes in pregnant women’s physical activity behaviour. In normalising physical activity during pregnancy and achieving better health outcomes for mothers and babies, it is necessary to consider the modifiable factors involved in behaviour change, identify opportune moments to intervene, and involve a network of professionals in facilitating and supporting pregnant women’s engagement with physical activities

    Free Your Mind-Unlock Your Inner Creativity

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    Creativity is a major factor in many careers, subjects, and disciplines. Although many people first assume engineering to be a field of study that does not require any creativity, it is actually an essential tool for successful engineers. The mark of a truly accomplished engineer is the ability to problem-solve effectively; in other words, to generate creative solutions. Although the goal as engineers is to become more creative throughout one’s career, is it even possible to gain creativity? Is creativity an innate quality, or a learned one? Since the engineering process demands creativity, we looked into how creativity can be improved, and how exactly it is used in the engineering design process. We surveyed engineering freshman students to determine how they view themselves and how important they think creativity is in relation to engineering. We then conducted research to see what creativity means to different people, how one can improve creativity according to various theories, and how creative processes have been used in past engineering projects. We presented this information to all sections of a second-semester engineering freshman course and surveyed the students at the beginning and end of the lecture to see how their views changed. We evaluated this data to discover if students perceive creativity as learned or innate and how it affects their idea on engineering. The students showed an improvement in awareness of the importance of creativity in engineering and how often it is used. Many did not change their opinion of themselves with regard to creativity but some actually ranked themselves lower after the presentation, presumably because they realized the extent of how creative some people are, especially in regard to engineering. The other data we analyzed was student responses to short questions. We asked students what qualities they associate with creative people and the most commonly used words were “thinks outside of the box,” “innovative,” “confident,” and “open minded.” We also asked what the best techniques for improving creativity within a group are. The most common answers were “different backgrounds,” “different ideas,” “being comfortable,” and “diversity.” These answers mirrored the overall message we attempted to portray throughout our presentation to a fair degree

    Bearings House: Community Reintegration Project

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    Research poster documenting the following project: Long Creek Youth Development Center offers a variety of activities, an education, mentorship, and structure for Bearings House residents. In addition to those programs, we hoped through building a relationship with residents we could identify their occupational interests and assist in their transition to life in the community. We strived to support residents through their transition to Bearings House and give them an opportunity to further explore their interests as well as expose them to new occupations they may have not previously participated in order to help as they reintegrate into the community.https://dune.une.edu/cecespring2020/1010/thumbnail.jp
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