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Listeria monocytogenes is a Gram-positive facultative anaerobe that is the causative agent of the disease listeriosis and is responsible for nearly 20% of all food-related deaths in the United States. The ability of this bacterium to cause infections is proposed to correlate to its ability to resist the bactericidal properties of bile acids found in bile. Bile resistance mechanisms have exhibited increased activity under anaerobic conditions. Therefore, we hypothesized that limited oxygen could enhance the bile resistance of L. monocytogenes. Upon survival analysis, viability for virulent strains F2365, EGD-e, and 10403S increased upon 10% porcine bile extract under anaerobic conditions. However, avirulent strain HCC23 depicted no difference in bile resistance. The proteomic analysis revealed increased expression of proteins associated with DNA repair and virulence factors under anaerobic conditions in a strain dependent manner. Therefore, oxygen availability may contribute to bile resistance through the regulation of the SOS response.

Some Arabidopsis lesion mimic mutants (LMM) show alterations in abiotic stress responses as well as pathogen resistance. cpr22 is a LMM which has a mutation in cyclic nucleotide-gated ion channels, is a typical LMM exhibiting elevated levels of salicylic acid (SA), spontaneous cell death, constitutive expression of defense genes, and enhanced resistance to various pathogens in an SA dependant manner. cpr22 defense responses are suppressed in high humidity and enhanced by low humidity. To investigate environmental effects, microarray analyses were conducted. Expression of several genes related to abscisic acid (ABA) signaling was altered and ABA levels increased in cpr22 after humidity shift. Furthermore, significant alterations in ABA-related phenotypes were observed. Double mutant analysis with nahG plants indicated that alterations in ABA signaling were attributable to elevated SA levels. These results suggest a negative effect of SA on ABA signaling/abiotic stress responses during the activation of defense responses.

Some Arabidopsis lesion mimic mutants (LMM) show alterations in abiotic stress responses as well as pathogen resistance. cpr22 is a LMM which has a mutation in cyclic nucleotide-gated ion channels, is a typical LMM exhibiting elevated levels of salicylic acid (SA), spontaneous cell death, constitutive expression of defense genes, and enhanced resistance to various pathogens in an SA dependant manner. cpr22 defense responses are suppressed in high humidity and enhanced by low humidity. To investigate environmental effects, microarray analyses were conducted. Expression of several genes related to abscisic acid (ABA) signaling was altered and ABA levels increased in cpr22 after humidity shift. Furthermore, significant alterations in ABA-related phenotypes were observed. Double mutant analysis with nahG plants indicated that alterations in ABA signaling were attributable to elevated SA levels. These results suggest a negative effect of SA on ABA signaling/abiotic stress responses during the activation of defense responses.

The objective of this study was to examine symptomatology; stress responses for everyday academic and social stressors; and cognitive coping resources among 11-year-old children adopted from Romanian orphanages. Two groups were established by the amount of time spent within the institutional system. Early adoptees (EAs, n=25) spent less than 6 months while late adoptees (LAs, n=14) endured 6 months or more of institutionalization. A comparison group of non adopted, same-age peers (Canadian Born (CBs), n=25) was included. The first goal was to investigate whether there were differences between EAs and LAs in ratings of symptomatology and stress responses. The second goal was to compare all Romanian adoptees (RAs) to CBs on the same set of factors. The third goal was to identify predictors of symptomatology and predictors of stress responses for RAs only. The main findings were as follows. EAs and LAs did not differ in any symptom ratings or stress responses, showing a lack of evidence for duration of deprivation as a grouping factor. Significant differences were detected by adoption status. Ratings were higher for RAs than CBs in parent-rated symptomatology, including the rate of RAs who exceeded the borderline clinical cut-off. RAs reported less secondary control coping for social stressors than CBs. Models to predict symptoms from stress responses were not supported, with one exception. More disengagement coping for social stress and less involuntary disengagement for academic stress predicted less externalizing and generalized symptoms by teacher report. Models to predict stress responses from cognitive coping resources were significant except for disengagement coping. One of the main findings was that predictors of secondary control coping varied by stressor domain. In conclusion, the findings were important in demonstrating that duration of deprivation does not differentiate between post-institutionalized preadolescents in aspects of psychosocial adjustment. Adoption status is a significant factor. Stress responses do not contribute to models of symptoms. The cognitive coping resources of perceived academic competency and social-support contribute to models of stress responses, yet with room to improve the predictive power of the models. Implications of the findings are discussed along with limitations and directions for future research.

The objective of this study was to examine symptomatology; stress responses for everyday academic and social stressors; and cognitive coping resources among 11-year-old children adopted from Romanian orphanages. Two groups were established by the amount of time spent within the institutional system. Early adoptees (EAs, n=25) spent less than 6 months while late adoptees (LAs, n=14) endured 6 months or more of institutionalization. A comparison group of non adopted, same-age peers (Canadian Born (CBs), n=25) was included. The first goal was to investigate whether there were differences between EAs and LAs in ratings of symptomatology and stress responses. The second goal was to compare all Romanian adoptees (RAs) to CBs on the same set of factors. The third goal was to identify predictors of symptomatology and predictors of stress responses for RAs only. The main findings were as follows. EAs and LAs did not differ in any symptom ratings or stress responses, showing a lack of evidence for duration of deprivation as a grouping factor. Significant differences were detected by adoption status. Ratings were higher for RAs than CBs in parent-rated symptomatology, including the rate of RAs who exceeded the borderline clinical cut-off. RAs reported less secondary control coping for social stressors than CBs. Models to predict symptoms from stress responses were not supported, with one exception. More disengagement coping for social stress and less involuntary disengagement for academic stress predicted less externalizing and generalized symptoms by teacher report. Models to predict stress responses from cognitive coping resources were significant except for disengagement coping. One of the main findings was that predictors of secondary control coping varied by stressor domain. In conclusion, the findings were important in demonstrating that duration of deprivation does not differentiate between post-institutionalized preadolescents in aspects of psychosocial adjustment. Adoption status is a significant factor. Stress responses do not contribute to models of symptoms. The cognitive coping resources of perceived academic competency and social-support contribute to models of stress responses, yet with room to improve the predictive power of the models. Implications of the findings are discussed along with limitations and directions for future research.

This thesis studied the influence of moisture content on the dynamic estimation of stiffness in wood of Pinus radiata D. Don. This is an important non-destructive measure for estimation of stiffness in standing trees, logs and lumber. Moisture content affects both acoustic velocity and density in the fundamental equation of dynamic MOE (DMOE = V²ρ, where V = acoustic velocity and ρ = density). Investigation included measurements with boards in the laboratory considering moisture contents below and above FSP as well as temperatures below and above 0°C. This also included field measurements of trees in contrasting climate sites and over different seasons including a long drought. Methods for measuring green density and moisture content and the patterns of variation of these parameters were also investigated. A secondary component of this thesis explored the wood quality and some mechanisms of tree response to water stress in two contrasting sites in terms or rainfall and water deficits in a region of Australia. The large increases in DMOE for frozen wood above the FSP (4.5 to 6 GPa) will limit the use of DMOE for grading logs in regions with freezing winters. Results from the experiment remeasuring young trees and the upper range of moisture content and temperatures above 0°C from the experiment with boards showed small to moderate variation in DMOE (0.1 to 1 GPa) which calls for further investigation on analytical procedures for adjustment of DMOE. Such procedures should consider that variations in acoustic velocity and density with changes in moisture content are not proportional and that there are counteracting effects between the two parameters. It remains to be investigated whether the typical variation (under normal climate conditions) in sapwood green density observed in our experiments has some implications for the use of DMOE. On the other hand, it is anticipated that the large differences along the stem and among stands in whole-section green density may bias DMOE measurements in logs for resource assessment. This also needs to be investigated. A comparison between acoustic velocity alone and DMOE for resource assessment under different scenarios is recommended. The study in two contrasting climate sites (high-altitude vs. warm-dry) in the Hume region of Forests NSW, Australia, including young (10-11 years) and mature trees (34 36 years) of radiata pine showed distinctive short and long-term responses of trees to cope with the water-limiting environment. In response to long-term water deficits the warm-dry site developed heartwood and thus reduced sapwood earlier and at faster rates than the high-altitude site. The onset of heartwood formation seemed to be triggered by some site threshold for water use as broadly indicated by the sapwood area/ha. The latter was consistently lower for the warm-dry site across the different stands. The warm-dry site also showed increased short-term responses to water stress and these were interpreted as seasonal mechanisms of the trees to cope with the limiting environment. The trees compensated for the lower available moisture and higher transpiration rates by lowering their saturation and disrupting water conduction at some points (cavitation). The inverse trends of cavitation spots and cavitation bands with height in the stem suggested the trees have different strategies to sacrifice conducting xylem depending on the position on the stem. Finally, it is suggested that saturation tended to fall to critical 'safe' levels as a result of water stress and this varied depending on age, site, and position in the stem. Significant decreases in DMOE and basic density were observed for the warm-dry site and were attributed to lower proportions of latewood due to lower rainfall for that site during the period of latewood formation. These showed no obvious association with any of the long-term water-stress traits (sapwood percentage and number of heartwood rings).

The incidence of bulimia has been increasingly documented in recent years. Treatments have focused on one behavior in the Binge-Purge chain or have combined several treatment components. This study was designed to assess the effect of teaching bulimics alternative responses for dealing with stressful events.

Constitutive and alternative splicing of pre-mRNAs from multiexonic genes controls the diversity of the proteome; these precisely regulated processes also fine-tune responses to cues related to growth, development, and biotic and abiotic stresses. Recent work showed that AS is pervasive across plant species, with more than 60% of intron-containing genes producing different isoforms. Mammalian cell-based assays have discovered various AS small-molecule inhibitors that perturb splicing and thereby provide invaluable tools for use as chemical probes to uncover the molecular underpinnings of splicing regulation and as potential anticancer compounds. Here, I show that the macrolide Pladienolide B (PB) and herboxidiene (GEX1A) inhibits both constitutive and alternative splicing, mimics an abiotic stress signal, and activates the abscisic acid (ABA) pathway in plants. Moreover, PB and GEX1A activate genome-wide transcriptional patterns involved in abiotic stress responses in plants. PB and GEX1A treatment triggered the ABA signaling pathway, activated ABA-inducible promoters, and led to stomatal closure. Interestingly, PB and GEX1A elicited similar cellular changes, including alterations in the patterns of transcription and splicing, suggesting that these compounds might target the same spliceosome complex in plant cells. This work establishes PB and GEX1A as potent splicing inhibitors in plants that can be used to probe the assembly, dynamics, and molecular functions of the spliceosome and to study the interplay between splicing stress and abiotic stresses, as well as having potential biotechnological applications.

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