Thesis (M.Sc.)--Memorial University of Newfoundland, 1994. / Typescript. Bibliography: leaves [116]-122. Also available online.

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<p>Odor discrimination ability was tested in four female South African fur seals (<em>Arctocephalus pusillus pusillus</em>) using a food-rewarded two-choice instrumental conditioning paradigm. The seals’ ability to distinguish between members of homologous series of aliphatic ketones (2-butanone to 2-heptanone) and alcohols (1-butanol to 1-heptanol) was assessed. The results showed that three out of four seals successfully discriminated between all of their stimulus combinations in both classes of odorants. One seal succeeded to reach the discrimination criterion with all 2-ketones but failed with all 1-alcohols.</p><p>No significant correlation between odor discrimination performance and structural similarity of the odorants in terms of differences in carbon chain length was found in either of the two chemical classes. Furthermore, it was found that the 2-ketones were significantly better discriminated than the 1-alcohols. The fact that both classes of odorants are known to be present in the natural environment of seals provides a possible explanation as to why most of the seals were able to successfully discriminate between them. The results of the present study support the notion that the sense of smell may play an important role in behavioral contexts such as social communication, foraging and reproductive behavior of fur seals.</p>

Odor discrimination ability was tested in four female South African fur seals (Arctocephalus pusillus pusillus) using a food-rewarded two-choice instrumental conditioning paradigm. The seals’ ability to distinguish between members of homologous series of aliphatic ketones (2-butanone to 2-heptanone) and alcohols (1-butanol to 1-heptanol) was assessed. The results showed that three out of four seals successfully discriminated between all of their stimulus combinations in both classes of odorants. One seal succeeded to reach the discrimination criterion with all 2-ketones but failed with all 1-alcohols. No significant correlation between odor discrimination performance and structural similarity of the odorants in terms of differences in carbon chain length was found in either of the two chemical classes. Furthermore, it was found that the 2-ketones were significantly better discriminated than the 1-alcohols. The fact that both classes of odorants are known to be present in the natural environment of seals provides a possible explanation as to why most of the seals were able to successfully discriminate between them. The results of the present study support the notion that the sense of smell may play an important role in behavioral contexts such as social communication, foraging and reproductive behavior of fur seals.

Nitrite at the level found in turkey frankfurter formulations vii did not interfere in the hydrazone test as developed by Andrews (1975). The aldehyde levels of frankfurters made principally from MD turkey meat were, on the average, twice as high as the levels in the raw meat. Aldehyde levels generally increased as the frozen storage time of the raw meat increased. There were some variations from this trend due to variation in the fat content of the raw meat. Sixty days was recommended as a maximum frozen storage time. However, because of variation in the fat content from sample to sample , assaying t he level of aldehyde in the raw meat was recommended as a more reliable method of predicting acceptability of further processed products than length of frozen storage. Aldehyde levels of less than two ppm in the raw meat and less than four ppm in the frankfurters were acceptable. The aldehyde measured by Andrews' hydrazone test was identified as formaldehyde.

The ease of electron loss of fifty alipathic thioethers was studied by electrochemistry, charge transfer and photoelectron spectroscopy. These compounds consisted of mesocyclic thioethers and S-methyl norbornane derivatives. Comparison of charge transfer and photoelectron ionization potential showed a good correlation. Correlation of ionization potential with anodic peak potentials showed the existence of two groups of compounds. Those compounds having an electron rich neighboring group capable of an intramolecular interaction were found to have a good correlation of ionization potential with electrochemical peak potential. For those compounds without this capability, no observable correlation was seen. Photoelectron ionization potentials of thioethers are a function of the alkyl groups attached to the sulfur atom. With substituent constants assigned to alkyl groups from measurements on simple thioethers, the ionization potential of more complicated thioethers can be calculated. Compounds whose experimental value was found to be less than the calculated value were found to fall in the group where an intramolecular neighboring group could facilitate the ease of electron loss by stabilization of the cation radical. Electrochemical peak potentials were seen to be dramatically affected by intramolecular stabilization of the cation radical. Shifts of 600-800 mV were seen for structurally similar compounds whose only difference was the availability of an electron rich neighboring group. Since the electrochemistry of these compounds exhibits irreversible behavior, the shift in peak potential could be due to a change in the formal potential, the heterogeneous rate constant, the rate of a following chemical reaction or a combination of these. Changes in the heterogeneous rate constant or chemical step rate constant alone cannot account for the magnitude of the shift seen. Thus the differences observed must be due to two different processes. In the noninteracting case, E⁰' is a measure of the formation of the cation radical, whereas, in the case of interacting compounds E⁰') is a measure of the formation of an intramolecularly stabilized cation radical where bond formation has occurred. Evidence for the structure of some intramolecular stabilized intermediates is presented. An electron deficient thioether which is a model for biological systems was shown to be capable of phosphorylating adenine nucleotides.

This thesis comprises three projects on the theme of catalytic C(sp3)–H carbonylation of secondary aliphatic amines. Chapter 2 describes the development of a general methyl C–H carbonylation of secondary aliphatic amines to form synthetically useful β-lactam building blocks. Amines exhibiting a range of substitution patterns around the nitrogen functionality, and bearing a wide variety of functional groups, could be tolerated in the reaction. The desired β-lactam products were delivered in high yields, with excellent selectivity observed for the β-C–H position. Computational studies suggested that the reaction proceeds through a novel carbamoyl cyclopalladation pathway, which is distinct from classical cyclopalladation. The subsequent discovery of a selective methylene C–H carbonylation of α-tertiary amines (ATAs) is discussed in chapter 3. By employing the ATA motif, remarkable levels of selectivity for β-methlyene C–H bonds were achieved, even in the presence of traditionally more reactive methyl C–H and C(sp2)–H bonds. Once more, the reaction was found to exhibit excellent functional group tolerance, delivering highly functionalised β-lactam building blocks in high yields and selectivity. Chapter 4 presents work towards the total synthesis of the marine natural product (±)cylindricine C. The key step of this synthesis was demonstrated to proceed in good yield and excellent selectivity.

Many objective chemical tests have attempted to correlate with organoleptic evaluation of oxidative rancidity. Major chemical tests used to detect oxidative rancidity of lipids measure nonvolatile high molecular weight carbonylic substances which make no considerable contribution to rancid flavors. High molecular weight carbonyls are present at much greater concentrations than volatile low molecular weight carbonyls. Peroxides and other unknown substances also react in these chemical tests to give at best an empirical evaluation. A 3-methyl-2-benzothiazolinone hydrazone chemical test is proposed which corrected some deficiencies of earlier procedures, and was correlated with organoleptic evaluation of rancid turkey samples. The proposed test measures oxidative rancidity in terms of milligrams of acetaldehyde per kilogram of sample. A comparison of the 3-methyl-2-benzothiazolinone hydrazone method with a widely used chemical test was conducted. The thiobarbituric acid test was selected because it is used most often as an indicator of rancidity. The thiobarbituric acid test values increased followed by a definite leveling off as formation of malonaldehyde reached a maximum even though rancid flavor continued to increase. The 3-methyl-2-benzothiazolinone hydrazone test measured a continuing increase of volatile aliphatic aldehydes as rancid flavor increased .

The toxic effects of degrading the chlorinated hydrocarbons trichloroethylene (TCE), chloroform (CF) and cis-1,2-dichloroethylene (cis-1,2-DCE) were studied in the bacterium Nitrosomonas europaea. N europaea is an ammonia-oxidizing bacterium that obtains all of its energy from the oxidation of ammonia to nitrite. This metabolic process involves two enzymes, ammonia monooxygenase (AMO) and hydroxylamine oxidoreductase (HAO). AMO has a broad substrate range and is also capable of oxidizing TCE, CF, and cis-1,2-DCE. Effects of degrading these chlorinated compounds on both AMO and HAO were studied. Cells were inactivated with known inhibitors of both AMO (light) and HAO (hydrogen peroxide) to provide comparison studies. Oxidation of the three chlorinated hydrocarbons did not always result in similar toxic effects to the cells. Whole cell studies indicated that oxidation of TCE and CF resulted in a loss of both NH������- and N���H���- dependent 0��� uptake rates, while in vitro studies indicated that at lower concentrations of both TCE (���0.05 mM) and CF (���0.10 mM) neither AMO or HAO appear to be the primary sites of inactivation. The oxidation of cis-1,2-DCE appeared to specifically inactivate AMO both in in vivo and in vitro assays. N europaea cells were also pretreated with the AMO inhibitor acetylene and incubated with the chlorinated hydrocarbons. Results of both whole cell 0��� uptake rates and the in vitro HAO assay confirms the hypothesis that the chlorinated hydrocarbons must be turned over in order to produce a toxic effect in N. europaea cells. / Graduation date: 1999

Graduation date: 1997