Life Sciences Commons^™

Extended X-Ray Absorption Fine Structure And Redox Potential Studies Of Heme-Substituted Horseradish Peroxidase And Myoglobin, Bing He

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Heme-substituted horseradish peroxidases and myoglobins were reconstituted from the apoenzyme using mesoheme and diacetyldeuteroheme. X-ray absorption spectroscopy was used to determine the dimensions of the active sites of these heme-substituted proteins, and were compared with those of the proto-hemeproteins. The change in the active-site structure corresponded with the electron withdrawing and donating effects of the different side chains. The oxidation-reduction potentials of Fe⁴⁺/Fe³⁺ couples of the heme-substituted proteins were measured at pH 7 with K₂IrCl₆. The oxidation-reduction potential sequence for compound I/compound II was diacetyldeutero- > proto- > meso- in horseradish peroxidase. The oxidation-reduction potential …

Uptake, Absorption, And Adsorption Kinetics Of Ferrous And Ferric Iron In Iron-Replete And Iron-Deficient Rats, Madhavi Ummadi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Various concentrations of ferrous and ferric iron solutions were held at room temperature for 60 min before they were assayed for ferrous iron, which may be unstable due to oxidation. The ferrous and ferric solutions (in pH 2 HCl) were maintained as such for 60 min without the use of chelators. There was no significant oxidation of ferrous iron. Also, four different levels of each ferrous and ferric iron were injected into proximal duodenal loops of rat intestine and uptake was determined at four different time intervals. Two iron-replete rats were assigned to each of the treatments. The in situ …

Pharmacokinetic Assessment Of The Influence Of Dietary Fiber On The Absorption And Disposition Of Selected Model Xenobiotics As It Relates To Colon Cancer, Joseph Donald Debethizy

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Selected drugs are being utilized as models of putative colon carcinogens in a study of the influence of major types of dietary fiber upon drug pharmacokinetics. Adult, male Wistar rats were pretreated with standardized, isocaloric hydrated gelatin diets containing no fiber or 15% (w/w) cellulose, lignin, hemicellulose (metamucil), or pectin for 30 days. An additional group was fed lab chow ad libitum as a reference control.

The pharmacokinetics of acetaminophen, FD & C Red No. 2 and mirex were examined following oral administration in three separate experiments. Among fiber types, pectin and hemicellulose (Metamucil) caused higher peak plasma concentrations of …

Pesticide Exposure Studies: Direct And Indirect Detection Of Absorption Of 2,4-D And Pronamide Herbicides In The Guinea Pig And Occupationally Exposed Workers, Ibrahim A.R. Al-Jabery

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A simple high pressure liquid chromatography procedure was used to determine 2,4-D and pronamide exposure in spraymen and their dermal absorption and excretion in guinea pigs.

Results of dermal application of these herbicides to guinea pigs demonstrated a strong correlation between the applied dermal dose and the urinary residue excretion over the dosage range tested. As the dosage was increased, the urinary excretion of residues was also increased. However, the excretion of 2,4-D amine mixture following dermal treatment of guinea pigs was prolonged as compared to that of pronamide.

Residue levels of these compounds were also determined to estimate skin …

Absorption, Translocation And Metabolism Of 1,3-Dichloropropene In Selected Plants, David L. Berry

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The absorption, translocation and metabolism of 1,3-dichloropropene (a soil fumigant) in bush beans, tomato and carrot was studied under growth chamber and greenhouse conditions using solution culture, vermiculite and sand. Absorption was monitored using gas chromatographic analysis and isotope techniques. Plants were shown to absorb a maximum amount of dichloropropene by 24 to 48 hr from solution culture and vermiculite. The plant absorbed and translocated 1,3-dichlorpropene-¹⁴C-U readily to aerial parts of the plant.

Bush beans, tomatoes and carrots absorbed and translocated 3-chlorallyl alcohol-¹⁴C-U from solution culture and vermiculite. Levels of 3-chloroallyl alcohol reached maximum at 24 …

Effect Of Stage Of Seedling Development On Absorption Of Selected Pre-Emergent Herbicides, Pairoj Suchinda

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Using radioautography ¹⁴C simazine, ¹⁴C EPTC, ¹⁴C 2,4-D, ¹⁴14 DCPA and ¹⁴C pyrazon absorption by seeds of bean (Phaseolus vulgaris L.), squash (Cucurbita maxima), corn (Zea mays), onion (Allium cepa) and oat (Avena sativa) was studied. Simazine, EPTC, 2,4-D and pyrazon were absorbed through the seed coat of bean, squash, corn and onion, the amount increasing with time. Little DCPA was absorbed by seeds of bean, squash, onion and oat. Distribution and translocation of ¹⁴C simazine, ¹⁴C EPTC and ¹⁴C pyrazon occurred in …

Absorption Of C14 Labeled Sucrose By Nectaries, Cecil Wright Lefevre

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Since the early Eighteenth Century the significance of nectar secretion has been debated. Some have reasoned that it is reabsorbed into the plant and used as energy for the developing embryo while others believe it is a waste product which attracts pollinating insects.

It has been suggested (Brink and Cooper, 1947) that the nutrient supply to developing ovules is a major factor in the development of seed. Also, alfalfa fields pollinated by pollen-collecting bees produce greater seed yields than those pollinated by nectar collectors (Bohart, Nye, and Levin, 1955). It is a well-known fact that more flowers are tripped by …

Thermodynamics Of Phosphate Absorption On Several Charcoals, James Duncan Beaton

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Phosphorus has long been recognized by agriculturists as being one of the elements essential for plant growth. Although the total phosphorus content of a soil may be high, the amount of phosphate actually available for plant growth is often low. Many agencies such as inherent low solubilities of phosphate compounds, adsorption on Ca C03, adsorption in the diffuse double layer of clay micelles, and chemical precipitation of phosphate which refers to the removal of phosphate ions from solution and their chemical bonding to the solid phase have been studied to explain the lack of phosphate availability.