Because the expression levels of housekeeping genes are relatively constant in most tissues, they are often useful controls when quantifying gene expression. We present an analytical method for identifying candidate housekeeping controls using expressed sequence tags (ESTs) from The Institute for Genomic Research Tomato Gene Index. We found relative expression levels for a collection of 127 transcripts and calculated the percentage of cDNA libraries that had expression levels (for a given transcript) within 2-fold through 10-fold ranges. When all libraries were considered together, the highest ranked housekeeping controls included transcripts for a DnaJ-like protein, translationally controlled tumor protein, two -tubulins, cyclophilin, and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). For each organ (leaf, root, fruit, and flower), at least one transcript was found that occurred within a 2-fold range of expression in all respective libraries. These included transcripts for -tubulin, DnaJ-like proteins, phosphoglycerate kinase, and GAPDH, although different transcripts appear better suited than others for different tissues. This analytical method is useful for identifying candidate housekeeping controls in particular tissues and at particular levels of expression and would be relevant for any species for which significant EST data exist.
This 5-year study of graduating seniors at Elon University ( n = 2,058) evaluates the impacts of experiential learning depth (amount of time commitment) and breadth (number of different types of experiences) on student outcomes. Data on study abroad, undergraduate research, internships, service, and leadership experiences were pulled from cocurricular transcripts and paired with responses to the National Survey of Student Engagement. Both depth and breadth were associated with acquiring a broad general education, writing clearly and effectively, contributing to the welfare of communities, relationships with faculty and administration, and desire to attend the same institution. Depth (but not breadth) was associated with higher order thinking (synthesis and application) in the senior year, as well as overall educational experience. Breadth (but not depth) was associated with working effectively with others and better relationships with other students. Overall, key learning outcomes desired for a college student are driven by both experiential learning depth and breadth.
This five-year study of graduating seniors at Elon University (n=1,858) compared student outcomes measured by the National Survey of Student Engagement across five study abroad groups: no study abroad, semester, short-term (3-week), two short-terms, and semester plus short-term. Both short-term and semester programs were positively associated with how students rate their overall educational experience and whether they would attend the same institution again. However, students who participated in semester programs reported better outcomes in numerous categories: contributing to class discussion, including diverse perspectives in discussions and assignments, synthesis of ideas, less rote memorization of course material, empathy,acquiring a broad general education,critical thinking,and working effectively with others. There was less compelling evidence of better outcomes from a second short-term program or one taken in addition to a semester program. Overall, short-term programs clearly have value, but semester programs are associated with significantly better outcomes overall.
Despite the major impacts of fire on plants, responses to fire damage have not been closely studied on the level of gene expression. Here, we present analyses of novel transcripts from tomato (Lycopersicon esculentum cv. Heinz), which are systemically upregulated in leaves after a distant leaf is wounded by flame. Nine cDNA fragments were isolated from a subtractive cDNA library of leaf tissue 1 h after flaming. Using data mining and polymerase chain reaction (PCR), full‐length open‐reading frames were predicted, amplified, and then sequenced. Real‐time (RT)‐PCR using leaf RNA after flaming confirmed the systemic accumulation of 4 and 7 transcripts within 30 and 60 min, respectively, before returning to basal levels within 3 h. During this same time course, proteinase inhibitor I levels gradually increased over 30‐fold in 6 h. Expression analyses also showed that eight of the transcripts are present in unwounded leaf, stem, and root tissues. The predicted proteins include an acyl carrier, adenylyl sulfate reductase, PS II oxygen‐evolving complex protein 3, anion : sodium symporter, chloroplast‐specific ribosomal protein, a histidine triad family protein, and an unknown wound/stress‐related protein. Homologs of several of these proteins have been associated with other types of wound and stress responses. It appears that, within an hour after being damaged by fire, plants systemically upregulate a variety of genes involved with basic cell metabolism and upkeep, in addition to classic defense genes such as proteinase inhibitors.
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