Fotosyntesen kallas den process som omvandlar ljusenergi till kemisk energi. Fotosyntesen sker i tylakoidmembranet och drivs av två stora proteinkomplex, fotosystem II (PSII) och fotosystem I (PSI) då de tillförs energi i form av fotoner. PSI-N är ett mindre protein på ca 10 kDa som ingår i PSI. På något sätt, som ännu inte är klarlagt, samverkar PSI-N med PSI-F och plastocyanin när det dockar till PSI. Det är därför av viktigt att rena fram större mängder av PSI-N för att få djupare kunskaper om proteinet samt dess struktur och funktioner. Tidigare undersökningar har utförts i ämnet och ett fusionsprotein innehållande PSI-N har uttryckts i Escherichia coli (E.coli). Problem har dock uppstått efter lysis av cellerna då det har visat sig att fusionsproteinet har degraderats. Vårt examensarbete strävar efter att rena fram intakt fusionsprotein med hjälp av, framför allt, mekanisk lysis och proteasinhibitorer. / The process where light is converted into chemical energy is called photosyntesis. The reaction takes place in the thylakoid membrane and is driven by two major protein complexes, photosystem II (PSII) and photosystem I (PSI) when energy in form of photons are received. PSI-N, a subunit in PSI, is a smaller protein with a mass of approximately 10 kDa. In some way, which is not yet clarified, PSI-N collaborates with PSI-F and plastocyanin when plastocyanin is docking to PSI. It is therefore important to purify larger amounts of the protein to acquire deeper knowledge of its structure and function. In earlier research the PSI-N protein has been expressed in Escherichia coli (E.coli). The problem has been degradation of the fusion protein after lysis. Our goal with this project is to obtain the purified protein intact using mechanic lysis and protease inhibitors.

The development of metal-tolerance and antibiotic resistance in bacteria may be caused by metals polluting a particular environment. During mining and mineral processing activities, large quantities of metals are deposited into the soil. These high concentrations of metals are evolutionary pressures selecting for microorganisms tolerant to these metals. Metaltolerance maybe conferred to these organisms by mobile genetic elements such as plasmids. This study describes the characteristics of plasmids isolated from various bacteria that displayed an ability to withstand high metal concentrations. The isolated plasmids were individually transformed into Escherichia coli JM109. Transformants were then evaluated for metal-tolerant capabilities using a microdilution approach. Plasmids were then isolated from the transformants and the concentration of the plasmid DNA ranged between 11.75 – 118.06 ng/μl. These plasmids were of the same size as the original ones. This demonstrated that successful transformations with plasmid DNA were conducted. In order to determine the compatibility group, plasmids were subjected to PCR amplification using IncQ, IncP-9 and IncW specific primers. Only the IncW provided positive results. To demonstrate that the plasmids were free of genomic DNA, a 16S rDNA PCR test was included. The plasmids that were positive for IncW PCRs were all negative for the rDNA PCRs. Plasmids were stably inherited and at least three, isolated from three different Gram positive species, belonged to the Inc W group of plasmids. These were originally isolated from Paenibacillus ginsingari, Paenibacillus lautus and Bacillus cereus. Minimum inhibition concentrations (MICs) were carried out to determine the ability of transformed E. coli JM109 to tolerate metals at varying concentrations. Results indicated that transformed E. coli JM109 developed ability to grow in the presence of several heavy metals. Some strains were resistant to high concentrations (+10 mM) of Ni2+/Al3+, Pb2+ and Ba2+. The order of metal resistance was Ni/Al=Pb>Ba>Mn>Cr>Cu>Co=Hg. All the x transformants were sensitive to 1 mM of Co2+ and Hg2+. Moreover, protein profiling was used to determine the impact of plasmids on E. coli JM109. Proteins were extracted from both transformed and un-transformed E. coli JM109 using acetone-SDS protocol and subjected to one-dimensional (1D) and two-dimensional (2D) Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS- PAGE). Transformed E. coli JM109 were grown under the metal stress. One dimension SDS-PAGE illustrated general similarity of the profiles except for two banding positions in the 30 to 35 kDa region where bands were present in the transformants that were grown in the Ni/Al alloy containing media. Twodimensional electrophoresis PAGE analysis showed that some of the proteins were upregulated while others were down-regulated. The largest numbers of proteins were from 15 – 75 kDa. The majority of these proteins had isoelectric points (pI) between 5 and 6. It was concluded that plasmids isolated from various heavy metal-tolerant bacterial species were successfully transformed into E. coli JM109 rendering various new metal-tolerant E. coli JM109 strains. Furthermore, the study showed that metal resistance was due to the presence of the plasmids. Two-dimensional SDS-PAGE resolved more differences in the protein expression profiles. Since the plasmids rendered the E. coli JM109 tolerant to metals tested, it also can be concluded that the change in the protein profiles was due to the effects of the plasmids. Furthermore, plasmids were also re-isolated from the transformants and these plasmids were of the same size as the original ones.. All the plasmids in this study were also stably inherited, a feature associated with IncW plasmids. More detailed genetic characterization of these plasmids is required. Plasmids isolated and characterized in this study may hold biotechnology potential. Such features should be exploited in follow-up experiments. / Thesis (Master of Environmental Sciences)--North-West University, Potchefstroom Campus, 2013.

The development of metal-tolerance and antibiotic resistance in bacteria may be caused by metals polluting a particular environment. During mining and mineral processing activities, large quantities of metals are deposited into the soil. These high concentrations of metals are evolutionary pressures selecting for microorganisms tolerant to these metals. Metaltolerance maybe conferred to these organisms by mobile genetic elements such as plasmids. This study describes the characteristics of plasmids isolated from various bacteria that displayed an ability to withstand high metal concentrations. The isolated plasmids were individually transformed into Escherichia coli JM109. Transformants were then evaluated for metal-tolerant capabilities using a microdilution approach. Plasmids were then isolated from the transformants and the concentration of the plasmid DNA ranged between 11.75 – 118.06 ng/μl. These plasmids were of the same size as the original ones. This demonstrated that successful transformations with plasmid DNA were conducted. In order to determine the compatibility group, plasmids were subjected to PCR amplification using IncQ, IncP-9 and IncW specific primers. Only the IncW provided positive results. To demonstrate that the plasmids were free of genomic DNA, a 16S rDNA PCR test was included. The plasmids that were positive for IncW PCRs were all negative for the rDNA PCRs. Plasmids were stably inherited and at least three, isolated from three different Gram positive species, belonged to the Inc W group of plasmids. These were originally isolated from Paenibacillus ginsingari, Paenibacillus lautus and Bacillus cereus. Minimum inhibition concentrations (MICs) were carried out to determine the ability of transformed E. coli JM109 to tolerate metals at varying concentrations. Results indicated that transformed E. coli JM109 developed ability to grow in the presence of several heavy metals. Some strains were resistant to high concentrations (+10 mM) of Ni2+/Al3+, Pb2+ and Ba2+. The order of metal resistance was Ni/Al=Pb>Ba>Mn>Cr>Cu>Co=Hg. All the x transformants were sensitive to 1 mM of Co2+ and Hg2+. Moreover, protein profiling was used to determine the impact of plasmids on E. coli JM109. Proteins were extracted from both transformed and un-transformed E. coli JM109 using acetone-SDS protocol and subjected to one-dimensional (1D) and two-dimensional (2D) Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS- PAGE). Transformed E. coli JM109 were grown under the metal stress. One dimension SDS-PAGE illustrated general similarity of the profiles except for two banding positions in the 30 to 35 kDa region where bands were present in the transformants that were grown in the Ni/Al alloy containing media. Twodimensional electrophoresis PAGE analysis showed that some of the proteins were upregulated while others were down-regulated. The largest numbers of proteins were from 15 – 75 kDa. The majority of these proteins had isoelectric points (pI) between 5 and 6. It was concluded that plasmids isolated from various heavy metal-tolerant bacterial species were successfully transformed into E. coli JM109 rendering various new metal-tolerant E. coli JM109 strains. Furthermore, the study showed that metal resistance was due to the presence of the plasmids. Two-dimensional SDS-PAGE resolved more differences in the protein expression profiles. Since the plasmids rendered the E. coli JM109 tolerant to metals tested, it also can be concluded that the change in the protein profiles was due to the effects of the plasmids. Furthermore, plasmids were also re-isolated from the transformants and these plasmids were of the same size as the original ones.. All the plasmids in this study were also stably inherited, a feature associated with IncW plasmids. More detailed genetic characterization of these plasmids is required. Plasmids isolated and characterized in this study may hold biotechnology potential. Such features should be exploited in follow-up experiments. / Thesis (Master of Environmental Sciences)--North-West University, Potchefstroom Campus, 2013.

<p>&nbsp / </p> <p align="left">One of the most common HIV-associated opportunistic infections is candidiasis, caused by <i><font face="TimesNewRoman,Italic">Candida albicans </font></i><font lang="KO" face="TimesNewRoman">or other </font><i><font face="TimesNewRoman,Italic">Candida </font><font lang="KO" face="TimesNewRoman">species. In immune suppressed subjects, this commensal organism can cause an increase in patient morbidity and mortality due to oropharyngeal or systemic dissemination. Limited information exists on the prevalence and antifungal susceptibility of </font><i><font face="TimesNewRoman,Italic">Candida </font><font lang="KO" face="TimesNewRoman">species in the African continent, the most HIV-affected region globally and home to new and emerging drug resistant </font><i><font face="TimesNewRoman,Italic">Candida </font><font lang="KO" face="TimesNewRoman">species. The mechanisms of </font><i><font face="TimesNewRoman,Italic">Candida </font><font lang="KO" face="TimesNewRoman">drug resistance in the African continent have also not been described. In this study, 255 </font><i><font face="TimesNewRoman,Italic">Candida </font><font lang="KO" face="TimesNewRoman">species isolated from the oral mucosa of HIV-positive South African and Cameroonian patients were identified using differential and chromogenic media and their drug susceptibility profiles tested using the disk diffusion method and the TREK Sensititre system, an automated broth microdilution method. </font><i><font face="TimesNewRoman,Italic">Candida </font><font lang="KO" face="TimesNewRoman">cell wall fractions were run on SDSPAGE and HPLC-MS with the aim of identifying peptides specifically expressed by antifungal drug resistant isolates. Comparisons between the two groups of isolates revealed differences in </font><i><font face="TimesNewRoman,Italic">Candida </font><font lang="KO" face="TimesNewRoman">species prevalence and drug susceptibility with interesting associations observed between specific drug resistance and duration of ARV therapy. This study showed that fluconazole, the drug of choice for the treatment of candidiasis in the African continent, is not an effective therapy for most cases of </font><i><font face="TimesNewRoman,Italic">Candida </font><font lang="KO" face="TimesNewRoman">infection, and suggests that regional surveillance be implemented in the continent. A multiple-drug resistant </font><i><font face="TimesNewRoman,Italic">Candida </font><font lang="KO" face="TimesNewRoman">strain was identified in this study, a finding that has not previously been documented. The use of proteomics tools allowed for the identification of peptides involved in drug resistance and the elucidation of </font><i><font face="TimesNewRoman,Italic">Candida </font><font lang="KO" face="TimesNewRoman">colonization mechanisms in HIV-infected African patients.</font></i></i></i></i></i></i></i></i></i></i></p>

<p>&nbsp / </p> <p align="left">One of the most common HIV-associated opportunistic infections is candidiasis, caused by <i><font face="TimesNewRoman,Italic">Candida albicans </font></i><font lang="KO" face="TimesNewRoman">or other </font><i><font face="TimesNewRoman,Italic">Candida </font><font lang="KO" face="TimesNewRoman">species. In immune suppressed subjects, this commensal organism can cause an increase in patient morbidity and mortality due to oropharyngeal or systemic dissemination. Limited information exists on the prevalence and antifungal susceptibility of </font><i><font face="TimesNewRoman,Italic">Candida </font><font lang="KO" face="TimesNewRoman">species in the African continent, the most HIV-affected region globally and home to new and emerging drug resistant </font><i><font face="TimesNewRoman,Italic">Candida </font><font lang="KO" face="TimesNewRoman">species. The mechanisms of </font><i><font face="TimesNewRoman,Italic">Candida </font><font lang="KO" face="TimesNewRoman">drug resistance in the African continent have also not been described. In this study, 255 </font><i><font face="TimesNewRoman,Italic">Candida </font><font lang="KO" face="TimesNewRoman">species isolated from the oral mucosa of HIV-positive South African and Cameroonian patients were identified using differential and chromogenic media and their drug susceptibility profiles tested using the disk diffusion method and the TREK Sensititre system, an automated broth microdilution method. </font><i><font face="TimesNewRoman,Italic">Candida </font><font lang="KO" face="TimesNewRoman">cell wall fractions were run on SDSPAGE and HPLC-MS with the aim of identifying peptides specifically expressed by antifungal drug resistant isolates. Comparisons between the two groups of isolates revealed differences in </font><i><font face="TimesNewRoman,Italic">Candida </font><font lang="KO" face="TimesNewRoman">species prevalence and drug susceptibility with interesting associations observed between specific drug resistance and duration of ARV therapy. This study showed that fluconazole, the drug of choice for the treatment of candidiasis in the African continent, is not an effective therapy for most cases of </font><i><font face="TimesNewRoman,Italic">Candida </font><font lang="KO" face="TimesNewRoman">infection, and suggests that regional surveillance be implemented in the continent. A multiple-drug resistant </font><i><font face="TimesNewRoman,Italic">Candida </font><font lang="KO" face="TimesNewRoman">strain was identified in this study, a finding that has not previously been documented. The use of proteomics tools allowed for the identification of peptides involved in drug resistance and the elucidation of </font><i><font face="TimesNewRoman,Italic">Candida </font><font lang="KO" face="TimesNewRoman">colonization mechanisms in HIV-infected African patients.</font></i></i></i></i></i></i></i></i></i></i></p>

Philosophiae Doctor - PhD (Biotechnology) / Guayule (Parthenium argentatum) is grown for its high quality hypoallergenic natural rubber latex production. The plant is native to the Chihuahua desert of North America and successful trials have been done in Europe, the United States of America (USA) and the Republic of South Africa (RSA). It is already undergoing industrial scale development in the USA producing good quality rubber products with impressive stretchiness and strength. The performance of guayule lines AZ1, AZ2, AZ3, AZ4, AZ5, AZ6, OSU1, and 11591 was investigated in the Eastern and Western Cape regions in RSA with an ultimate goal of leading to commercial production. To ensure continuous supply of plants, and avoiding documented seed dormancy issues, a micropropagation protocol was established using the OSU1 guayule line. In addition, laboratory scale latex extraction was accomplished using the Waring blender method with KOH pH 11 buffer and the amount of latex was quantified using the 1 ml latex quantification method. The extracted latex homogenate from the different guayule lines was pooled and purified using Sodium Carboxymethyl Cellulose. The efficiency of different molecular weights (90 000, 250 000 and 700 000) of Sodium Carboxymethyl Cellulose was determined in creaming guayule latex at room temperature and 4 degrees celcius. The optimal creaming results were incorporated into creaming latex extracted from the different guayule lines during this study.

Philosophiae Doctor - PhD / One of the most common HIV-associated opportunistic infections is candidiasis, caused by Candida albicans or other Candida species. In immune suppressed subjects, this commensal organism can cause an increase in patient morbidity and mortality due to oropharyngeal or systemic dissemination. Limited information exists on the prevalence and antifungal susceptibility of Candida species in the African continent, the most HIV-affected region globally and home to new and emerging drug resistant Candida species. The mechanisms of Candida drug resistance in the African continent have also not been described. In this study, 255 Candida species isolated from the oral mucosa of HIV-positive South African and Cameroonian patients were identified using differential and chromogenic media and their drug susceptibility profiles tested using the disk diffusion method and the TREK Sensititre system, an automated broth microdilution method. Candida cell wall fractions were run on SDSPAGE and HPLC-MS with the aim of identifying peptides specifically expressed by antifungal drug resistant isolates. Comparisons between the two groups of isolates revealed differences in Candida species prevalence and drug susceptibility with interesting associations observed between specific drug resistance and duration of ARV therapy. This study showed that fluconazole, the drug of choice for the treatment of candidiasis in the African continent, is not an effective therapy for most cases of Candida infection, and suggests that regional surveillance be implemented in the continent. A multiple-drug resistant Candida strain was identified in this study, a finding that has not previously been documented. The use of proteomics tools allowed for the identification of peptides involved in drug resistance and the elucidation of Candida colonization mechanisms in HIV-infected African patients.

The aim of the thesis was to determine the content of pure tuber proteins, patatin relative abundance in total tuber protein, and subsequently its antioxidant potential. The theoretical part dealt with general potato characteristics, potato tuber chemical composition and description of analyzed cultivated and wild potato species. In the practical part results of laboratory analysis were presented. It was determined statistically significant genotype variability of antioxidant activity for potato tuber protein as well as for potato tuber dry matter here ranging from 0.221 (Solanum berthaultii 07S0300031) to 0.0066 mg of ascorbic acid/g dry matter (Solanum tuberosum cultivar Kuras). Any direct relationship between potato tuber protein content or patatin relative abundance and antioxidant activity was found. The findings are compared with the literature.

The use of various types of gel electrophoresis for characterization and identifying plant varieties is well estabilished. This diploma work deals with the possibility characterize potato cultivar (Solanum tuberosum L.) by the help of electrophoretic technique SDS {--} PAGE tuber protein profiles. Soluble potato tuber proteins can be classified according to their molecular weight (kDa) into three groups: First, the major tuber protein patatin (37 {--} 44 kDa); second, a group constituted of protease inhibitors (6 {--} 24 kDa); and third group containing all other proteins. First two group manifest genetic variability, which is necessary evalute for its potential using of potato cultivar characterization.

Made available in DSpace on 2014-06-11T19:29:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2002-07-26Bitstream added on 2014-06-13T18:39:27Z : No. of bitstreams: 1 ferreira_fp_me_ilha.pdf: 272949 bytes, checksum: 557ad0d6f0ab0423f56e4256406ff28d (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Toxocara vitulorum é um parasita nematódeo de alta freqüência no trato intestinal de búfalos, particularmente em bezerros búfalos de um a três meses de idade. Devido à sua alta morbidade e mortalidade, causa consideráveis prejuízos a bubalinocultura. A pesquisa objetivou a obtenção de antígenos de extrato larval solúvel bruto (Ex), do material excretor-secretor (ES) de larvas infectantes e do líquido perientérico (Pe) de adultos de T. vitulorum, bem como a separação das frações protéicas na mistura pelo SDS-PAGE, seguida da análise imunológica por Western blot (WB), utilizando-se soros imunes e colostros de búfalos naturalmente infectados com T. vitulorum além de camundongos imunes. O acompanhamento do quadro parasitário dos bezerros búfalos também foi realizado. Pôde-se verificar que os três antígenos, Pe, Ex e ES, apresentaram mobilidades eletroforéticas pelo SDS-PAGE revelando nove (11,5, 14,2, 31, 38, 58, 76, 88, 112 e 165 KDa), onze (11,2, 13,3, 16,5, 22, 25, 32, 43, 53, 68, 82 e 96 KDa) e oito (19, 48, 56, 64, 90, 110, 150 e 190 KDa) bandas protéicas, respectivamente. A maioria dessas frações separadas pela eletroforese, foi reconhecida por todos as amostras de soros e pelo colostro, quando analisada pelo WB. No entanto, somente as bandas de alto peso molecular (68 - 190 KDa) persistiram nos grupos de bezerros búfalos que se encontravam no pico, declínio ou expulsão e na ausência ou autocura, à exceção do antígeno ES, que desapareceu durante o processo de autocura. Já os soros de bezerros búfalos com um de vida, que mamaram o colostro e os daqueles que se encontravam em fase de aparecimento ou ascensão, revelaram com as mesmas frações detectadas no soro e no colostro das búfalas. Os três antígenos reagiram de forma cruzada entre si, quando foram testados com soros homólogos e heterólogos de camundongos imunizados experimentalmente com estes antígenos de T. vitulorum / Toxocara vitulorum is a nematode parasite of small intestine of cattle and water buffaloes particularly buffalo calves with one to three months of age, causing high morbidity and mortality. The purpose of this research was the antigen obtaintion and characterization of crude soluble larval extract (Ex), excretory-secretory (ES) of infective larvae, and perienteric fluid (Pe) from adults of T. vitulorum, as well as the separation of protein fractions from the antigenic mixture by SDS-PAGE and analysis of each band by Western blot (WB), using immune sera and colostrum of buffaloes naturally infected by T. vitulorum, and mice experimentally immunized. The parasitological status of the buffalo calves was also evaluated using sequentially coprological examinations. The results showed that three antigens, Pe, Ex and ES, revealed nine (11,5, 14,2, 31, 38, 58, 76, 88, 112, and 165 KDa), eleven (11,2, 13,3, 16,5, 22, 25, 32, 43, 53, 68, 82, and 96 KDa) and eight (19, 48, 56, 64, 90, 110, 150, and 190 KDa) protein bands by SDS-PAGE, respectively. The majority of these isolated bands were recognized by sera and colostrum of all groups of infected animals (buffalo cows one day post parturition and buffalo calves in five different periods of T. vitulorum infection) analyzed by WB. However, only the fractions of high molecular weight (68 - 190 KDa) persisted in the groups of buffalo calves at maximum peak of infection, expulsion and post-expulsion of the parasite or self-cure process, excepting ES antigen, that was not detected during the self-cure process. Sera of buffalo calves at one day of age, after suckling the colostrum and at the beginning of infection reacted with the same bands detected by serum and colostrum of the buffalo cows. The three antigens showed crossed reaction among themselves, when they were tested with homologous and heterologous sera of mice experimentally immunized with them