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No description available.

The present project aimed at measuring plant heavy metal uptake as a function of transpiration rates and dissolved heavy metal level in the soil solution. Two experiment was conducted separately in two season (Spring and Fall 2000). In these two experiments, young wheat plants ( Triticum aestivum) were irrigated with nine different solutions containing Cd and Zn. The study was conducted in two chambers where relative humidity was controlled to obtain two different levels of transpiration rates. Each control chambers contained 27 pots filled with sand and seeded with wheat plants, each nine triplicated pots receiving a different treatment: three Cd treatments with levels of 0.01, 0.10, and 0.50 mg/L; one Zn treatment with level of 25mg/L and four treatment combinations of Cd/Zn with levels of 0.01 Cd/25Zn, 0.10Cd/25ZN, 0.50Cd/25Zn and 0.50Cd/50Zn mg/L. The transpiration rate of the plants was monitored over a period of 30 days, measured from the emergence of the plants by weighing the pots daily. On day 15 and 30, three plants were removed from each pot, to weigh their dry matter production and to analyze their heavy metal uptake. (Abstract shortened by UMI.)

Birds nest under electric and magnetic fields (EMFs) generated by transmission liners which may affect their reproductive success and/or melatonin governing their circadian and circannual cycles. Over two years, captive kestrels were used to determine whether EMFs affect their plasma melatonin concentrations and their reproductive success. EMFs were equivalent to that which wild kestrels are exposed to while nesting under 735 kV transmission fines, and daily exposure used in the captive study (88--98% time budget) was potentially equivalent to that of wild kestrels (90% X, 80% X). Captive kestrels were housed in control or EMF conditions to determine short-term (one season; S-EMF) and longer-term EMF (two seasons; L-EMF) effects. / Plasma melatonin in adult EMF males was suppressed at 42 d and elevated at 70 d of EMF exposure compared to controls. Melatonin levels in EMF males at mid-season were similar to controls at season's end, suggesting a seasonal phase-shift. Melatonin was suppressed in L-EMF fledgling birds but not in adult females or nudes (1995) at 70 d. Plasm melatonin, higher in adult males than females at 70 d post-pairing, was not directly associated with body mass changes in kestrels. / Captive EMF birds were more active and alert but groomed less often than controls. EMF exposure affected reproductive success of kestrels. Fertility and fledging success were higher, and hatching success lower in S-EMF clutches. Hatching success was higher, but fledging success lower in L-EMF clutches. In S-EMF clutches, mean egg volume and mass were greater, eggs had slightly more albumen but thinner eggshells, and embryos were larger than controls. L-EMF hatchlings were heavier than controls. / The melatonin results for male kestrels indicate that kestrels perceive EMFs as light, thus altering their photoperiod. Photoperiodic manipulations advance molt onset, which is associated with increased body mass in male kestrels. S-EMF males were heavier at 56 d of exposure when molt began, but this was unlikely related to feed intake winch was unchanged. EMF exposure had no effect on body mass and pectoral muscle scores of reproducing females. The sexually-dimorphic response in body mass and melatonin concentrations suggests that male kestrels may be more sensitive to EMF exposure than females.

Controversy exists concerning the role that dopamine plays in analgesia. In the present studies, dopamine agonists produced analgesia, and D-amphetamine potentiated morphine analgesia, while treatment with 6-hydroxydopamine or mixed or selective D1 and D2 dopamine receptor antagonists attenuated or abolished morphine and D-amphetamine-induced analgesia, in the formalin test. Furthermore, microinjection of morphine into the ventral tegmental area (VTA) and ventral striatum produced analgesia, while intra-VTA microinjection of naloxone methylbromide antagonized the analgesia produced by systemic morphine, in the formalin test. In contrast, similar manipulations of dopamine had little or no effect in the tail flick test. Thus, dopamine appears to play a facilitatory role in formalin test analgesia, and there appear to be fundamental differences between the formalin and tail flick tests and parallels between the role of dopamine in the formalin test and in clinical pain, the vocalization after-discharge test and reward.

The effect of salinity on phosphorus (P) absorption kinetics by 'Russet Burbank' cv. potato propagated by tissue culture technique was studied in the laboratory. Nine clones of the cultivar were evaluated for their salt tolerance at the vegetative stage by using in vitro culture. Four concentrations of NaCl (0, 40, 80, and 120 mM) were used in the experiments. The first experiment was carried out to study the effect of salinity on P absorption by using radiophosphorus ($ sp{32}$P) as a marker. P absorption showed a quadratic relationship with time. In general, there was a significant reduction in P absorption as the NaCl concentration increased in the nutrient medium. However, the root tip concentration of $ sp{32}$P increased with increased salt concentration. When P concentration in the nutrient medium was increased, $ sp{32}$P activity was also increased with time at 120 mM salt concentration. The activity of radiophosphorus decreased on root tips when P concentration in the nutrient medium was increased to 2.5 mM P. The second experiment was conducted in tissue culture using nodal cutting bioassay. The plant morphological parameters of shoot length, shoot fresh weight, shoot dry weight, root length, root fresh weight, and root dry weight were reduced for all nine clones as salinity increased. The clone PEI#1 (tu) exhibited high salt tolerance characteristics.

This study is an investigation into the relationship between numeric cognition and aging. Specifically, older and younger adults engaged in an experimental protocol that allowed observation of number comparison accuracy and response time latencies associated with the SNARC effect, the distance effect, and number format. The experimental protocol featured a computerized magnitude comparison task wherein the participants were prompted to identify the larger of two numbers. Half of the trials featured whole numbers and half featured fractions. The number stimuli were consistently mapped such that half of all trials were at near distance (i.e., difference of 2) or far distance (i.e., difference of 4) and half of all trials had the larger numerosity on the left side of space and the other half with the larger numerosity on the right side of space. Older adults were significantly slower and less accurate than young adults. Both age groups were significantly slower and less accurate when comparing fractions as opposed to comparing whole numbers. The SNARC effect impaired accuracy in both age groups but did not significantly impact response times. The distance effect impacted both age cohorts in accuracy but differentially impacted older adult response times more than young adult response times. The results of this study support the model of numeric cognition as an automatic process when comparing whole numbers at a far distance and this process is not disrupted by the SNARC effect but is when comparing whole numbers at near distance. The results also indicate that fraction comparison is a controlled process even when the fraction stimuli are consistently mapped. Further investigation is necessary to understand the amount of cognitive resources necessitated by fraction processing and if training can improve fraction comparison.

Probiotics are a live microbial supplement that reside within the intestinal tract and are considered normal flora. The Balb/c mouse model was used to determine if the elimination of probiotics, general LAB species, by antibiotics plays a role in the breakdown of oral tolerance leading to the generation of an immune response to oral antigens. A mouse model was developed for in vivo research regarding probiotic populations and the effect on the induction of oral tolerance. The Balb/c mouse was used to determine if the mouse model had a colonized intestinal tract with probiotics followed by a reduction of probiotics that was done with orally administered antibiotics. After the reduction of probiotics, mice were fed oral antigen, ovalbumin, to determine that an immune response was not shown with oral antigen alone. After the mouse model was set up, mice were then fed oral antigen and then stimulated with immunizations to study the induction of oral tolerance and the possible effect of the absence of probiotics. The results indicated that mice with reduced probiotics and fed with oral antigen alone do not show an immune response. In contrast, mice fed with oral antigen followed by immunization indicate a higher OVA-specific serum IgG. This is evidence that correlates with clinical findings in disease states such as Crohn's Disease and Irritable Bowel Syndrome (IBD). / Department of Biology

Cultured tobacco cells (Nicotiana tabacum L., cv Wisconsin-38) were subjected to temporary sub-lethal heat and salt shock treatments to determine the effects of these treatments on various physiological parameters after subsequent lethal heat or salt stresses. Tobacco cells developed a tolerance to a non-permissive temperature stress (54C for 14 min) when pretreated with heat shock of 38C for 2h but not when pretreated at 42C for 2h. Cells pretreated at 38 (2h) exhibited less than 30% normal growth when the 54C stress came immediately after the 38C treatment. Tolerance to the 54C stress developed with increased interval between shock and stress with cells exhibiting 95% normal regrowth when the 54C stress was administered 8h after the 38C shock. The developement of heat tolerance was inhibited if heat shock was done in the presence of a non-injuring level of EGTA (.0.5mM). Cells treated with EGTA during heat shock grew normally at 23C but not after a 54C heat stress. EDTA (0.5mM) had little effect on the acquisition of tolerance to heat stress.Wisconsin-38 cells developed a tolerance to a non-permissive salt stress (2% NaCl for 16h) when pretreated at a lower salt level (1.2% NaCl) for 3h. Cells heat shocked at 38C exhibited increased tolerance of the lethal salt stress up to 8h. Conversely, cells heat shocked at 42C exhibited immediate tolerance to lethal salt stress and this tolerance decayed over eight hours. The heat shock-induced acquisition of salt tolerance was inhibited by both EGTA and EDTA.Proteins synthesized during heat and salt stress treatments were labeled with [35S]-methionine and/or [3H]-leucine and separated using Sodium dodecylsulfate polyacrylamide gel electrophoresis. Fluorographic analysis of the gels indicate that a number of proteins are produced in response to heat shock. Similar analysis of proteins from salt shocked cells indicates that no salt shock proteins are produced in response to a brief low-level sodium chloride shock.

While a great deal of research has been directed towards the phenomena of excess post exercise oxygen consumption (EPOC), the effect of thermal stress on EPOC is not well defined. To assess the effect of heat stress on EPOC, seven healthy, active subjects (4 female, 3 male; 23.9 ± 2.0 years of age) performed 4 trials: one control (quiet rest) and one exercise (45 minutes of cycling at 65% VO2max workload) trial in moderate (23° C, 50% humidity) and hot (35° C, 50% humidity) environments. Oxygen consumption (V02), heart rate (HR) and rectal temperature (RT) were assessed pre, during and post control or exercise. Subjects were monitored until post exercise VO2 had returned to within ±2% of baseline. EPOC was determined by subtracting baseline VO2 from total V02 during the post exercise period. During the first 15 minutes (acute) post exercise, a significant EPOC (p = 0.0019) was seen in both exercise conditions over both control conditions. During the slow phase (> 15 minutes post exercise to baseline), there was no significant difference between the hot control (HC), moderate exercise (ME), or hot exercise (HE) EPOC. Total time post exercise until baseline was achieved was 35, 44, and 51 minutes for HC, ME, and HE respectively. HR was significantly elevated in both exercise conditions. During the acute post exercise period, HR in HE was elevated above MC, ME and HC (p < 0.05). RT was elevated in both exercise conditions during and post exercise. The present data indicate that heat stress does not have a significant effect on the magnitude or duration of EPOC. / School of Physical Education