In this thesis work the accuracy of the spherical harmonic synthesis and analysis are investigated, by simulated numerical studies.The main idea is to investigate the loss of accuracy, in the geopotential coeffcients, by the following testing method. We start with a synthesis calculation, using the coefficients(EGM2008), to calculate geoid heights on a regular grid. Those geoid heights are then used in an analysis calculation to obtain a new set of coeffcients, which are in turn used to derive a new set of geoid heights. The difference between those two sets of geoid heights will be analyzed to assess the accuracy of the synthesis and analysis calculations.The tests will be conducted with both point-values and area-means in the blocks in the grid. The area-means are constructed in some different ways and will also be compared to the mean value from 10000 point values as separate tests. Numerical results from this investigation show there are signifi…cant systematic errors in the geoid heights computed by spherical harmonic synthesis and analysis, sometimes reaching as high as several meters. Those big errors are most common at the polar regions and at the mid-latitude regions.

This thesis is concerned with the chemical modification of polymers in the preparation of a library of materials which exhibit altered surface properties as a result of the surface chemical functionality, with particular emphasis on the development of materials that control biofouling and are antibacterial. Chemical modification of crosslinked polystyrene, in film and microsphere form, was carried out by carbene insertion followed by diazonium coupling. This provided access to a collection of materials with varying surface chemistry, whilst the bulk properties of the polystyrene substrates were maintained. Synthesis of the diaryldiazo and the diazonium salts used to perform the surface modifications is described, as well as the preparation and characterisation of the materials. Analysis of the ability of the materials to adsorb and bind the protein bovine serum albumin (BSA) is presented with data obtained from two methods of observation. Quartz Crystal Microbalance with Dissipation (QCM-D) and a protein assay based on the change in optical density of a BSA/PBS solution are used to demonstrate how the specific surface chemistry of the materials influences the ability to adsorb and bind protein. The behaviour of the materials was time dependent and was rationalised with respect to the surface water contact angle and the calculated parameters polar surface area and % polar surface area of the functional groups added to the surfaces. Finally, penicillin loaded materials were prepared and their antibacterial activity was tested against E. coli and S. aureus, demonstrating that the antibiotic is still active from within the polystyrene scaffold.

<p>Grupno-strukturna analiza naftnih kiselina izolovanih iz srednjih uljnih&nbsp;komercijalnih frakcija vojvođanske nafte &bdquo;Velebit&rdquo; rađena je analizom IR-,&nbsp;¹H- i&nbsp;¹³C NMR- i ESI-MS spektara niske rezolucije. Određeno je &scaron;est klasa&nbsp;karboksilnih kiselina op&scaron;te molekulske formule C_nH_2n-ZO₂. To su karboksilne&nbsp;kiseline u opsegu masa 240-466 sa 15-31 C atoma u molekulu koje su&nbsp;grupisane u pet cikloalkil Z-serija: monociklična- (C_nH_2n-2O₂, 14.72%),&nbsp;biciklična- (C_nH_2n-4O₂, 34.63%), triciklična- (C_nH_2n-6O₂, 25.03%), tetraciklična- (C_nH_2n-8O₂, 10.04%), pentaciklična klasa karboksilnih kiselina (C_nH_2n-10O₂, 4.99%) i jedna alkanska klasa kiselina sa alkil grupama otvorenog niza (C_nH_2nO₂, 10.57%).</p><p>Razdvajanjem na bazi različite kiselosti i njihove rastvorljivosti u vodi na&nbsp;određenim pH vrednostima u rasponu od pH 2-10 dobijeno je devet užih&nbsp;frakcija kiselina. Ekstrakcijom sa etrom u vodi nerastvornih kiselina u rasponu&nbsp;od po jedne pH jedinice dobijena je sledeća distribucija masa: 9.57% (pH 10),&nbsp;12.69% (pH 9), 5.91% (pH 8), 4.85% (pH 7), 2.44% (pH 6), 11.71% (pH 5),&nbsp;23.94% (pH 4), 16.76% (pH 3) i 10.12% (pH 2). Razdvajanjem kiselina na bazi&nbsp;njihove kiselosti oko 50% mase kiselina ekstrahovano je od pH 2-4, znači u&nbsp;grupi jačih kiselina. Masenom spektrometrijom niske rezolucije ESI-MS na&nbsp;pH 4 vidi se da su u sme&scaron;i kiselina skoncentrisane kiseline sa vi&scaron;e prstenova u&nbsp;alkilnom delu sa maksimumom na tricikličnim kiselinama (36.50%), dok su&nbsp;pojedinačno najzastupljenije tetraciklične strukture kiselina C₂₀H₃₂O₂(4.43%) i&nbsp;C₂₁H₃₄O₂(4.56%). Na pH 8 biciklične- i triciklične strukture su zastupljene&nbsp;ukupno sa 65.02% sa maksimalno zastupljenim kiselinama sa 20-26 C atoma&nbsp;u molekulu, a izdvajaju se C₂₂H₃₈O₂ (5.26%)&nbsp;biciklične- i C₂₄H₄₂O₂(7.01%)&nbsp;triciklične strukure, a od tetracikličnih struktura kiselina izdvaja se C₂₄H₄₀O_2&nbsp;(4.77%). Na pH 10 najzastupljenije izolovane kiseline su aciklične, odnosno&nbsp;masne kiseline zastupljene sa 25.28%, a najdominantnije su strukture&nbsp;C₂₁H₄₂O₂ (4.83%), dok su ostale klase kiselina ujednačene po svom masenom&nbsp;udelu u odnosu na sastav u ukupnoj polaznoj sme&scaron;i kiselina.&nbsp;Drugi deo rada obuvata derivatizaciju izolovanih prirodnih naftnih kiselina.&nbsp;Sintetizovani su funkcionalni kiseonični metil-, etil-, n-butil-,&nbsp; terc-butil- i&nbsp;benzil-derivati naftnih kiselina kao i funkcionalni azotni derivati: amidi i anilidi&nbsp;naftnih kiselina. Sinteze navedenih estara rađene su klasičnim postupcima i&nbsp;modifikovanom metodom esterifikacije u kiselo-katalizovanim uslovima&nbsp;upotrebom mikrotalasa kao ko-katalizatora, &scaron;to je imalo za cilj skraćenje&nbsp;reakciong vremena i pobolj&scaron;anje ekolo&scaron;kih sintetskih uslova.<br />Modifikacijom sinteze metilnaftenata MT-zagrevanjem 48 puta je skraćeno&nbsp;vreme trajanja sinteze, prinosi ni promenom reakcionih parametara (vreme,&nbsp;snaga MT) nisu bitno promenjeni. Strukturnom analizom ESI-MS spektra&nbsp;polaznih kiselina i metilnaftenata dobijenih metilovanjem naftnih kiselina&nbsp;utvrđeno je da je odnos klasa u dobroj podudarnosti. Prinos estara u ovoj&nbsp;sintezi je 95.47%. Esterifikacija naftnih kiselina etil alkoholom rađena je u&nbsp;uslovima kisele katalize uz konvencionalno zagrevanje (91.76%), a&nbsp;modifikacijom metode MT-zagrevanjem (150 W) reakciono vreme je skaćeno&nbsp;96 puta (92.19%). Esterifikacija naftnih kiselina n-butil alkoholom rađena je uz&nbsp;sumpornu kiselinu kao katalizator i uz konvencionalno zagrevanje (94.24%), a&nbsp;u uslovima MT-zagrevanja (150 W) 72 puta je skraćeno reakciono vreme&nbsp;(61.15%). Sinteza terc-butilnaftenata rađena je prevođenjem naftnih kiselina u&nbsp;hloride a zatim reakcijom sa terc-butil alkoholom nastaju terc-butilnaftenati&nbsp;(80.17%). Modifikovanom metodom klasične reakcije esterifikacije naftnih&nbsp;kiselina terc-butil alkoholom katalizovanom sumpornom kiselinom u uslovima&nbsp;MT-zagrevanja (150 W) ostvaren je prinos od 85.49% a vreme trajanja reakcije&nbsp;je 5 minuta. Sinteza benzilnaftenata rađena je prevođenjem naftnih kiselina u&nbsp;hloride a zatim reakcijom sa benzil alkoholom nastaju benzilnaftenati&nbsp;(84.43%), a modifikovanom metodom klasične kiselo-katalizovane&nbsp;esterifikacije naftnih kiselina benzil alkoholom u uslovima MT-zagrevanja&nbsp;(150 W) ostvaren je prinos od 85.49% uz reakciono vreme od 5 minuta.&nbsp;Sinteza amida naftnih kiselina rađena je iz hlorida reakcijom sa amonijakom.&nbsp;Prinos čistih amida je 65.74%, a reakcija amidacije sa amonijakom trajala je&nbsp;15 minuta. Strukturnom analizom ESI-MS spektra amida naftnih kiselina&nbsp;utvrđen je grupno-strukturni sastav amida. Među strukturama amida naftenskih&nbsp;kiselina takođe su dominantne biciklične- i triciklične strukture, kao i u sme&scaron;i&nbsp;slobodnih kiselina. Sinteza anilida naftnih kiselina rađena je iz hlorida reakcijom sa anilinom. Prinos čistih anilida je 96.48%, a reakcija amidacije anilinom trajala je 30 minuta. Strukturnom analizom ESI-MS spektra anilida naftnih kiselina utvrđen je grupno-strukturni sastav proizvoda, anilida. Među strukturama anilida naftenskih kiselina takođe su dominantne biciklične- i triciklične strukture kao i u sme&scaron;i slobodnih kiselina.</p><p>U trećem delu ovog rada ispitivana je biolo&scaron;ka aktivnost naftnih kiselina&nbsp;auksinskog i giberelinskog tipa, njihov uticaj na ožiljavanje reznica,&nbsp;ukorenjivanje bočnih grana i mikroizdanaka biljaka, na aktivnost biljnih&nbsp;hormona, kao i na usvajanje metalnih jona kod biljaka.&nbsp;</p><p>Aktivnost naftenskih kiselina utvrđena je pomoću tri in vitro&nbsp; biolo&scaron;ka testa.&nbsp;&bdquo;Koleoptil test&rdquo;, rađen je na dva supstrata, odnosno na semenu ozime p&scaron;enice&nbsp;novosadske sorte Partizankai jare p&scaron;enice takođe novosadske sorte Venera.&nbsp;Referentna aktivnost u testu rađena je sa -naftilsirćetnom 3-indolsirćetnom&nbsp;kiselinom. U oba testa ustanovljen je približno isti odnos aktivnosti rastvora&nbsp;naftenskih kiselina i aktivnosti standardnih biljnih hormona. &bdquo;Test inhibicije&nbsp;klijanja&rdquo; semena rađen je sa semenom crne slačice, Brasscia nigra. Najveći&nbsp;uticaj naftenskih kiselina na inhibiciju klijanja postignut je u rasponu&nbsp;koncentracija kiselina od 10^-7&nbsp;-10^-8&nbsp;mol/L (0.05-0.01 mg/L). Testovi za &scaron;est užih&nbsp;frakcija dobijenih iz sme&scaron;e ukupnih kiselina razdvajanjem na bazi različite&nbsp;rastvorljivosti pri različitim pH vrednostima pokazuju istu aktivnost kao&nbsp;3-indolsirćetna kiselina (0.5 mg/L), a da je frakcija izdvojena iz vodenog&nbsp;rastvora na pH 7 takođe aktivna ali u poređenju sa 3-indolsirćetnom kiselinom&nbsp;to je 10 puta niža aktivnost. Hormonska aktivnost giberelenskog tipa ispitivanih&nbsp;kalijumovih soli naftenskih kiselina utvrđena je &bdquo;Endosperm testom&rdquo;, u kojem je&nbsp;određivana aktivnost amilaze spektrofotometrijskim praćenjem povećanja&nbsp;koncentracije redukujućih &scaron;ećera u endospermu semena tretiranog ječma i&nbsp;poređena sa aktivno&scaron;ću rastvora giberelinske kiseline (GA3). Rezultati ovih&nbsp;testova pokazuju da delovanjem vodenih rastvora užih frakcija naftenskih&nbsp;kiselina u koncentraciji 1.0 mg/L (3.5 x 10^-6mol/L)frakcija izolovana pri pH 8&nbsp;ima aktivnost koja je približno u opsegu aktivnosti giberelina koncentracije&nbsp;10^-2-10^-3&nbsp;mg/L.&nbsp;</p><p>Natrijum-naftenati u koncentraciji od 10^-6&nbsp;<br />do 10^-8&nbsp;mol/L stimuli&scaron;u formiranje&nbsp;adventivnih korenova kod reznica suncokreta pa je broj korenova po biljci 40&nbsp;puta veći kod biljaka koje su bile potopljene u rastvor natrijum-naftenata u&nbsp;odnosu na one koje su bile potopljene u vodu, a sličan efekat utvrđen je i pri&nbsp;tretiranju bočnih grana suncokreta.&nbsp;</p><p>Ožiljavanje drvenastih biljaka rađeno je na reznicama bele topole (Populus&nbsp;alba) i reznicama američke crne topole (Populus deltoides). Uočen je jasan&nbsp;inhibitomi efekat na rast korenčića i izbojka u vodenom medijumu sa 10^-4&nbsp;mol/L&nbsp;naftenskih kiselina, dok je tretman od 24 časa doprineo većem broju korenčića&nbsp;na donjih 5 cm reznice, kao i ukupnog broja korenčića nego kod kontrole.&nbsp;</p><p>U testu ukorenjivanja mikroizdanaka kod hrizantema najveći broj korenova&nbsp;dobijen je nakon tretmana sa rastvorom koji sadrži 10 &micro;mol/L ukupnih naftenata&nbsp;i tretmanom sa 50 &micro;mol/Lfrakcijom kiselina izolovanom pri pH 7. Oba rezultata&nbsp;su na nivou aktivnosti 3-indolbuterne kiseline koncentracije 10 &micro;mol/L&scaron;to znači&nbsp;da u ovom slučaju frakcionacija nije neophodna.&nbsp;</p><p>Efekti natrijum-naftenata na ukorenjivanje praćeni su merenjem nivoa totalnih&nbsp;peroksidaza i amilaze, &nbsp;kao i sadržaja redukujućih &scaron;ećera i ukupnih proteina u&nbsp;bazalnim delovima reznica bagrema(Rozaszin-AC).&nbsp; Nakon 1; 3 i 6 dana&nbsp;reznice su uzete za biohemijske analize. U svakom slučaju, aktivnosti&nbsp;IAA-oksidaze i amilaze su se povećavale do trećeg dana, &nbsp;a zatim smanjuje.&nbsp;Efekat je bio jače izražen posle tročasovnog tretmana sa natrijum-naftenatima&nbsp;u poređenju sa &scaron;estočasovnim tretmanom i kontrolom. Sadržaj rastvornih&nbsp;proteina je bio povećan jedan dan posle tretmana, smanjen trećeg i ponovo povećan &scaron;estog dana, osim za &scaron;estočasovni tretman natrijum-naftenatima, kada je efekat bio sasvim suprotan.</p><p>Test uticaja naftnih kiselina na nivo kadmijuma u biljkama pokazuje fiziolo&scaron;ko delovanje naftnih kiselina na snižavanje nivoa te&scaron;kih metala u biljci, u ovom slučaju kadmijuma. Ispitivan je efekat niske koncentracije natrijum-naftenata (10^-7&nbsp;mol/L) na ukupan sadržaj Cd u pojedinim frakcijama interćelijskog prostora kao i unutar ćelija, kao i na neke fiziolo&scaron;ke i biohemijske parametre kod mladih biljaka soje koje su uzgajane u prisustvu kadmijum-hlorida koncentracije 1 mmol/L. Prisustvo naftenata smanjuje sadržaj ukupnog kadmijuma kako u korenu tako i u stablu i listovima u proseku za oko 40% i ublažava &scaron;tetne efekte kadmijuma na aktivnost nitrat-reduktaze kao i na sadržaje fotosintetskih pigmenata.</p><p>Tretman biljaka niskim koncentracijama natrijum-naftenata utiče na&nbsp;akumulaciju nekih esencijalnih elemenata kod mladih biljaka soje. Prisustvo&nbsp;naftenata (10^{-7 &nbsp;}mol/L) značajno povećava sadržaj Mn, Fe, Zn i Ni u korenu, ali&nbsp;u stabljici i listovima samo sadržaj Fe i Mn. U korenu, sadržaj Mn je četiri puta&nbsp;veći a sadržaji Fe, Zn i Ni su povećani 17%, 60% i 68%, respektivno.&nbsp;</p><p>Ispitivanja na celeru i mrkvi su potvrdila da uticaj naftenata na mineralnu&nbsp;ishranu zavisi od primenjenog elementa i da je način preuzimanja određenih&nbsp;jona različit, &scaron;to ima za posledicu ili povećanje ili smanjenje sadržaja pojedinih&nbsp;jona u nekim delovima biljaka. Mlade biljke celera i mrkve, gajene u hranljivom&nbsp;medijumu, tretirane su natrijumovim solima naftenskih kiselina (10^-7&nbsp;mol/L)&nbsp;folijarno ili prisustvom u hranljivom medijumu. Jedino je tretman putem&nbsp;prisustva naftenata u hranljivom medijumu smanjio svežu masu korena i&nbsp;nadzemnog dela oko 20% kod obe biljke.Oba tretmana uticala su na sadržaj&nbsp;Fe, Cu, Mn, Mg i Ca kod biljaka celera i Fe, Mn, Zn i Na kod biljaka mrkve.&nbsp;Kod biljaka celera do&scaron;lo je do smanjenja sadržaja navedenih nutrienata dok je&nbsp;u korenu biljaka mrkve do&scaron;lo do povećanja sadržaja Fe za 45%, Mn za 70% i&nbsp;Zn za 37%. Kod ovih biljaka prisustvo naftenata u hranljivom medijumu dovelo&nbsp;do smanjenja mase korenova i nadzemnih delova, &scaron;to je potpuno suprotno od&nbsp;rezultata dobijenih kod biljaka soje.&nbsp; Folijarnim tretmanom je značajno<br />povećana masa nadzemnog samo kod celera.</p> / <p>Group-structural analysis of naphthenic acids isolated from middle&nbsp;commercial fractions of Vojvodina oil &bdquo;Velebit&rdquo; was performed with the&nbsp;analysis of IR-,<br />¹H- and&nbsp;¹³C NMR- and ESI-MS low resolution spectrums.&nbsp;Six classes of carboxylic acids of the general molecular formula C_nH_2n-ZO_2&nbsp;were determined. These are carboxylic acids with mass range of 240-466&nbsp;with 15-31 C atoms in molecule which are grouped in five cycloalkyl&nbsp;<span style="font-size: 12px;">Z-series: monocyclic- (C_nH_2n-2O₂, 14.72%), bicyclic- (C_nH_2n-4O₂, 34.63%),&nbsp;</span><span style="font-size: 12px;">tricyclic- (C_nH_2n-6O₂, 25.03%), tetracyclic- (C_nH_2n-8O₂, &nbsp;10.04%), pentacyclic&nbsp;</span><span style="font-size: 12px;">class of carboxylic acids (C_nH_2n-10O₂, 4.99%) and one alyphatic class of&nbsp;</span><span style="font-size: 12px;">acids with open chain alkyl groups (C_nH_2nO₂, 10.57%).</span></p><p>By fractioning on the basis of different levels of acidity and their solubility in&nbsp;water with pH values ranging from pH 2-10 nine subfractions of acids were&nbsp;obtained. By extraction with ether in water undissolved acids in the range of&nbsp;one pH unit the following distribution of mass was performed: 9.57%&nbsp;(pH 10), 12.69% (pH 9), 5.91% (pH 8), 4.85% (pH 7), 2.44% (pH 6), 11.71%&nbsp;(pH 5), 23.94% (pH 4), 16.76% (pH 3) and 10.12% (pH 2). By fractioning&nbsp;acids on the basis of their acidity about 50% of acid &nbsp;mass was extracted at&nbsp;pH 2-4, i.e., in the group of stronger acids. Low resolution mass&nbsp;spectrometry ESI-MS shows that at pH 4 acids with more rings in the alkyl&nbsp;<br />section were concentrated in the mixture with maximum at tricyclic acids&nbsp;(36.50%), while individually tetracyclic acid structures C₂₀H₃₂O₂ (4.43%) and&nbsp;C₂₁H₃₄O_2&nbsp;(4.56%) were most prominent. At pH 8 bicyclic- and tricyclic&nbsp;structures are represented &nbsp;together by 65.02% with acids with 20-26 C&nbsp;atoms in molecule being represented the most, and C₂₂H₃₈O₂&nbsp; (5.26%)&nbsp;bicyclic- and C₂₄H₄₂O₂(7.01%) tricyclic structures stand &nbsp;out, while with&nbsp;tertacyclic acid structures C₂₄H₄₀O₂ (4.77%) stands out. At pH 10 most&nbsp;represented isolated acids are acyclic, i.e., fatty acids which are&nbsp;represented by 25.28%, with the most dominant C₂₁H₄₂O_2&nbsp;structures&nbsp;(4.83%), while the other classes &nbsp;of acids are well balanced in their mass&nbsp;share in relation to the composition of the overall initial acid mixture.</p><p>The second part of this work deals with derivatization of the isolated natural&nbsp;naphthenic acids. Functional oxygen methyl-, ethyl-, n-butyl-, tert-butyl and&nbsp;benzyl-derivatives of naphthenic acids as well as functional nitrogen&nbsp;derivatives: amides and anilides of naphthenic acids were synthesized. The&nbsp;syntheses of the above mentioned esters were performed by conventional&nbsp;methods and by a modified method of esterification in acid-catalyzed&nbsp;conditions using microwaves as a co-catalyst with the aim of shortening the&nbsp;reaction time and improving the ecological synthetic conditions.&nbsp;</p><p>By modification of methyl naphthenates synthesis using MT-heating the&nbsp;time period for synthesis is reduced 48 times and the yield does not&nbsp;significantly change even after the reaction parameters (time, MT power)&nbsp;have been altered. Using structural analysis of ESI-MS spectrum of initial&nbsp;carboxylic acids and the methyl naphthenates obtained through methylation&nbsp;of naphthenic acids it was establishedthat the class ratio shows great&nbsp;compatibility. The esters yield in this synthesis is 95.47%. The esterification&nbsp;of naphthenic acids with ethyl alcohol done under the conditions of acid&nbsp;catalysis with conventional heating (91.76%), and with the modified method&nbsp;MT-heating (150 W) the reaction time is reduced 96 times (92.19%). The&nbsp;esterification of naphthenic acids with n-butyl alcohol was performed using&nbsp;sulphuric acid as a catalyst with conventional heating (94.24%), and under&nbsp;MT-heating conditions (150 W) reaction time was 72 times&nbsp; shorter&nbsp;(61.15%). The synthesis of&nbsp; tert-butyl naphthenates was performed by&nbsp;conversion of naphthenic acids into chlorides, followed by the reaction with&nbsp;tert-butyl alcohol which resulted in tert-butyl naphthenates (80.17%). By the&nbsp;modified method of conventional reaction of esterification of naphthenic&nbsp;acids using tert-butyl alcohol catalysed with sulphuric acid in MT-heating&nbsp;conditions (150 W) the yield was 85.49% and reaction time was 5 minutes.&nbsp;The synthesis of benzyl naphthenates was performed by conversion of&nbsp;naphthenic acids into chlorides, followed by a reaction with benzyl alcohol&nbsp;which produces benzyl naphthenates (84.43%), whereas the modified&nbsp;method of conventional acid-catalysed esterification of naphthenic acids&nbsp;using benzyl alcohol under MT-heating (150 W) conditions the yield was&nbsp;85.49% with the reaction time of 5 minutes.&nbsp;</p><p>The synthesis of naphthenic acid amides was done from chlorides by&nbsp;reaction with ammonia. The yield of pure amides was 65.74%, and the&nbsp;reaction of amidation with ammonia lasted for 15 minutes. The structural&nbsp;analysis of ESI-MS spectrum of naphthenic acid amides determined the&nbsp;group-structural composition of amides. With the structures of amides of&nbsp;naphthenic acids bicyclic- and tricyclic structures are also dominant, as in&nbsp;the mixture of free acids. The synthesis of naphthenic acid anilides were&nbsp;performed from chloride by reacting with aniline. The yield of pure anilides&nbsp;<br />was 96.48%, and the reaction of amidatation lasted for 30 minutes. The&nbsp;structural analysis of ESI-MS spectrum of naphthenic acid anilides&nbsp;determined the group-structural composition of anilide products. With the&nbsp;structures of anilides of naphthenic &nbsp;acids bicyclic- and tricyclic structures&nbsp;are also dominant, as in the mixture of free acids.</p><p>The third part of this work tests the biological activity of naphthenic acids of&nbsp;auxine and gibberellinic type, their influence on the rooting of cuttings,&nbsp;lateral branches and microshoots of plants, on the activity of plant&nbsp;hormones as well as on the metal ions uptake by plants.&nbsp;</p><p>The activity of naphthenic acids was determined using three in vitro&nbsp;biological tests. &bdquo;Koleoptil test&rdquo;, was done on two substrates, namely the&nbsp;seed of winter wheat of the Partizankasort and the spring wheat of the&nbsp;Venerasort. The referential activity in the test was performed with&nbsp;&alpha;-naphthylacetic- and 3-indolacetic acid. Both tests showed approximately&nbsp;the same ratio of activity of naphthenic acid solutions and standard plant&nbsp;hormones. &bdquo;Germination Inhibition Test&rdquo; of the seed was performed using&nbsp;<br />Brasscia nigraseed. The greatest influence of naphthenic acids to&nbsp;germination inhibition was achieved in the acid concentration ranging from&nbsp;10^-7-10^-8&nbsp;mol/L (0.05-0.01 mg/L). The tests for six narrow fractions obtained&nbsp;from the overall mixture of acids through fractioning on the basis of different&nbsp;solubility at different pH values show the same activity as 3-indolacetic acid&nbsp;(0.5 mg/L), with the fraction isolated from the aqueous solution at pH 7 also&nbsp;active but in comparison to 3-indolacetic acid this activity was 10 times&nbsp;lower. Hormone activity of gibberellinic type of the potassium salts of&nbsp;naphthenic acids was determined using &ldquo;Endosperm Test&rdquo; where amylase&nbsp;<br />activity was determined by spectrophotometric measuring of the increase of&nbsp;the concentration of reducing sugars in endosperm in the treated barley&nbsp;seed which was then compared to the activity of the gibberellic acid solution&nbsp;(GA3).&nbsp; The results of these tests indicate that the activity of aqueous&nbsp;solutions of narrow fractions of naphthenic acids in the concentration of&nbsp;1.0 mg/L (3.5 x 10^-6&nbsp;mol/L)the fraction isolated &nbsp;at pH 8 has the activity&nbsp;which is approximately within the range of activities of gibberellin of the&nbsp;concentration of 10^-2-10^-3&nbsp;mg/L.&nbsp;</p><p>Sodium salts of naphthenic acids in concentrations of 10^-6&nbsp;do 10^-8&nbsp;mol/L&nbsp;stimulated formation of adventitious roots in&nbsp;<span style="font-size: 12px;">sunflower cuttings even by a&nbsp;</span><span style="font-size: 12px;">factor of 40 compared with control, the effect being also observed lateral&nbsp;</span><span style="font-size: 12px;">branches of interspecies sunflower hybrids. The obtained results suggest&nbsp;</span><span style="font-size: 12px;">the possibility of using naphthenic acids as a means for rooting of plant&nbsp;</span><span style="font-size: 12px;">cuttings.</span></p><p>Rooting of hardwood plants was investigated on the cuttings of white poplar&nbsp;(Populus alba) and black poplar (Populus deltoides). The distinct inhibitory&nbsp;effect on the root and shoot growth in water culture was detected in the&nbsp;concentration of naphtenic acids 10^-4&nbsp;mol/L, but 24-hour treatment raised&nbsp;the number roots on undermost 5 cm of the cutting, as well as the total&nbsp;number of roots, comparing to the control.</p><p>In the test of rooting microshoots ofchrysanthemum the highest number of&nbsp;<span style="font-size: 12px;">roots was achieved after the treatment with solution containing 10 &micro;mol/L of&nbsp;</span><span style="font-size: 12px;">total napthenates, as &nbsp;well as after the treatment with fraction of naphthenic&nbsp;</span><span style="font-size: 12px;">acids which was isolated at pH &nbsp;7 in concentration of 50 &micro;mol/L. Both results&nbsp;</span><span style="font-size: 12px;">are on the level of activity of 3-ndolbutyric acid in concentration of 10 &micro;mol/L&nbsp;</span><span style="font-size: 12px;">which suggests that in this case ractionation is not necessary.</span></p><p>The effects of sodium naphthenates on rooting were investigated by&nbsp;measuring the level of total peroxidases and amylase, along with the&nbsp;contents of reducing sugars and total proteins in basal parts of cuttings of&nbsp;black locust (Rozaszin-AC). After 1; 3 and 6 days cuttings were taken for&nbsp;biochemical analysis. In all cases, the activities of IAA-oxidase and amylase&nbsp;increased to the third day and showed a decrease afterwards. The effect&nbsp;was more pronounced after the three-hour treatment with sodium&nbsp;naphthenates, compared to the six-hour treatment and control. The content&nbsp;of soluble proteins increased one dayafter the treatment and decreased to&nbsp;the third and again increased to the sixth day, an exception being the&nbsp;six-hour treatment with sodium naphthenate, when the effect was&nbsp;completely opposite.</p><p>The test of naphthenic acids influence on the level of cadmium in plants&nbsp;showed physiological activity of naphthenic acids on the decrease of the&nbsp;level of heavy metals, &nbsp;in this case cadmium, in the plant. The effect of low&nbsp;concentrations (10^-7&nbsp;mol/L) of sodium naphthenate on total content of Cd in&nbsp;the intercellular space and inside cells, as &nbsp;well as on some physiological&nbsp;and biochemical parameters of young soybean plants grown in the&nbsp;presence of 1 mmol/L solution of cadmium chloride was investigated.&nbsp;Presence of naphthenate reduced in average by 40 % content of total and&nbsp;intracellular Cd in root, stem and leaves and alleviated the harmful effect of&nbsp;<br />Cd on activity of nitrate reductase and content of photosynthetic pigments.</p><p>Treatment of soybean plants with low concentrations of sodium&nbsp;naphthenate influenced the accumulation ofsome essential elements by the&nbsp;young plants. The presence of naphthenates (10^-7&nbsp;mol/L) significantly&nbsp;increased content of Mn, Fe, Zn and Ni in root, but in stem and leaves&nbsp;increased only contents of Fe and Mn. Inroot, the content of Mn increased&nbsp;four times while contents of Fe, Zn and Ni increased by 17%, &nbsp;60% and 68%&nbsp;respectively compared to the control.</p><p>Investigations on celery and carrot&nbsp; confirmed that the influence of&nbsp;naphthenates on mineral nutrition depends on the applied element and that&nbsp;the way of uptake of certain ions is different, which results in either increase&nbsp;or decrease of the contents of some ions in certain parts of plants. Young&nbsp;plants of celery and carrot, were grown in the nutrient medium and treated&nbsp;with sodium salts of naphthenic acids (10^-7&nbsp;mol/L) over the leaves or with its&nbsp;presence in the nutrient medium. Only the treatment based on the &nbsp;presence&nbsp;of naphthenates in the nutrient medium resulted in the decrease of the fresh&nbsp;mass of root and aboveground part by about 20% for both plants. Both&nbsp;treatments had influence on the content of Fe, Cu, Mn, Mg and Ca in the&nbsp;plants of celery and Fe, Mn, Zn and Na in the plants of carrots. In the plants&nbsp;of celery the content of the mentioned nutrients was decreased, while in the&nbsp;root of plants of carrot &nbsp;the content was increased, Fe by 45%, Mn by 70%&nbsp;and Zn by 37%. With these plants &nbsp;the presence of naphthenates in the&nbsp;nutrient medium caused the reducing roots and aboveground parts, which is&nbsp;completely opposite from the results obtained with soybean plants. The&nbsp;treatment by leaves significantly increased the mass of aboveground part&nbsp;only with celery.</p>

Indiana University-Purdue University Indianapolis (IUPUI) / Fatty acid elongation is the extension of de novo synthesized fatty acids through a series of four reactions analogous to those of fatty acid synthase. ELOs catalyze the first reaction in the elongation pathway through the condensation of an acyl group with a two carbon unit derived from malonyl-CoA. This study uses the condensing enzyme, EloA, from the cellular slime mold, Dictyostelium discoideum as a model for the family of ELOs. EloA has substrate specificity for monounsaturated and saturated C16 fatty acids and catalyzes the elongation of 16:1Δ9 to 18:1Δ11. Site-directed mutagenesis was used to change residues highly conserved among the ELO family to examine their potential role in the condensation reaction. Mutant EloAs were expressed in yeast and fatty acid methyl esters prepared from total cellular lipids were analyzed by gas chromatography/mass spectrometry. Sixteen out of twenty mutants had a decrease in 18:1Δ11 production when compared to the wild-type EloA with little to no activity observed in ten mutants, four mutants had within 20% of wild-type activity, and six mutants had 10-60% of wild-type activity. Immunoblot studies using anti-EloA serum were used to determine if the differences in elongation activity were related to changes in protein expression for each mutant. Analysis of immunoblots indicated that those mutants with little to no activity, with the exception of T130A and Q203A, had x comparable protein expression to the wild-type. Further research included the solubilization of the His6-ELoA fusion protein and preliminary work toward the isolation of the tagged protein and the use of a radiolabeled condensation assay to determine the activity of the eluted protein. Preliminary results indicated that the protein was solubilized but the eluted protein showed no activity when examined by a condensation assay. The work presented here contributes to a better understanding of the role of certain amino acid residues in the activity of EloA and serves as a stepping-stone for future EloA isolation work.

Indiana University-Purdue University Indianapolis (IUPUI) / Fatty acid synthase (FASN) is over-expressed in many cancers, and novel inhibitors that target FASN may find use in the treatment of cancers. It has been shown that orlistat, an FDA approved drug for weight loss, inhibits the thioesterase (TE) of FASN, but can be hydrolyzed by TE. To understand the mechanisms of TE action and for designing better FASN inhibitors, I examined the mechanism of orlistat hydrolysis by TE using molecular dynamics simulations. I found that the hexyl tail of orlistat undergoes a conformational transition, destabilizing a hydrogen bond that forms between orlistat and the active site histidine. A water molecule can then hydrogen bond with histidine and become activated to hydrolyze orlistat. These findings suggest that rational design of inhibitors that block hexyl tail transition may lead to a more potent TE inhibitor. To search for novel inhibitors of TE, I performed virtual DOCK screening of FDA approved drugs followed by a fluorogenic assay using recombinant TE protein and found that proton pump inhibitors (PPIs) can competitively inhibit TE. PPIs, which are used for the treatment of gastroesophageal reflux and peptic ulcers, work to decrease gastric acid production by binding irreversibly with gastric hydrogen potassium ATPase in the stomach. Recently, PPIs have been reported to reduce drug resistance in cancer cells when used in combination with chemotherapeutics, although the mechanism of resistance reduction is unknown. Further investigation showed that PPIs are able to decrease FASN activity and cancer cell proliferation in a dose-dependent manner. These findings provide new evidence that FDA approved PPIs may synergistically suppress cancer cells by inhibiting TE of FASN and suggests that the use of PPIs in combinational therapies for the treatment of many types of cancer, including pancreatic cancer, warrants further investigation.

Indiana University-Purdue University Indianapolis (IUPUI) / The modification of brucine derivatives as chiral ligands and the use of a multifaceted chiral ligand, brucine diol, under different reaction conditions to produce various optical isomers is described. In Chapter 1, the generation of a number of brucine derivatives is described. Taking the advantage of brucine-diol’s excellent molecular recognition capability for multiple organic functional groups, we focused on the synthetic modifications of brucine-diol and the synthesis of brucine N-oxide. We also produced various brucine derivatives with different functional moieties in good yields and selectivities. In Chapter 2, we described the investigation of brucine N-oxide catalyzed Morita-Baylis-Hillman (MBH) reaction of alkyl/aryl ketones. Brucine N-oxide was used as a nucleophilic organic catalyst in the MBH reaction of alkyl vinyl ketone. In addition, asymmetric MBH reactions of alkyl vinyl ketones with aldehydes were investigated using a dual catalysis of brucine N-oxide and proline. In this dual catalyst system, proline was found to form iminium intermediates with electron-deficient aryl aldehydes, while the N-oxide activated vinyl ketones provided enolates through the conjugate addition. Our dual catalysis approach also allowed the development of MBH reaction of aryl vinyl ketones. In Chapter 3, brucine diol-copper complex catalyzed asymmetric conjugate addition of glycine (ket)imines to nitroalkenes is discussed. Stereodivergent catalytic asymmetric conjugate reactions for glycine (ket)imines with nitroalkenes were achieved using various chiral catalysts derived from a single chiral source, brucine diol. Both syn- and anti-conjugate addition products were obtained with high diastereoselectivity and enantioselectivity. In Chapter 4, enantiodivergent production of endo-pyrrolidines from glycine (ket)imines using brucine diol-copper complex is described. The [3+2] cycloaddition reaction of glycine imines and activated alkenes was performed to produce endo-pyrrolidines. The reversal of enantioselectivity was observed for endo-pyrrolidines between concerted and stepwise reaction pathways. The three new brucine derivatives produced in this study would potentially work as organocatalysts and chiral ligands with metal ion in asymmetric synthesis. The brucine diol-metal complex catalyzed reactions laid a good foundation for catalytic asymmetric reactions, where a single chiral source was used to control the absolute and the relative stereochemical outcomes of reactions. Understanding the molecular-level interactions between catalyst and substrates will provide insightful mechanistic details for the stereodivergent approaches in asymmetric catalysis.