The aim of this diploma thesis was to identify and quantify the content of taste and aroma active compounds and to evaluate flavour of cheese analogue samples with various vegetable fats (coconut, palm, butter and mixed oils and butter) and differently matured Edam cheese using selected sensory methods. The samples were produced at Tomas Bata University in Zlín. Aroma compounds were extracted using SPME and assessed using gas chromatography. In total 43 compounds were identified, 14 alcohols, 9 aldehydes, 7 ketones, 8 acids, 5 esters and 1 terpene. Simultaneously the analogues were sensorially evaluated using scale, profile and ranking tests. The influence of storage time, type of fat and Edam cheese used on content of aroma compounds and sensory quality of analogues were evaluated. The cheese analogues with butter were sensorially evaluated as the best, with mixed oil as the worst. From the point of view of aroma compounds content, the significant differences between samples were evident. Using more matured Edam cheese, the content of aroma compounds declined, however, these samples were sensorially evaluated as better. The content of aroma compounds decreased also with storage time, which is more obvious in less matured Edam cheese. So all above mentioned factors influence the content of aroma compounds and thus the flavour of cheese analogues.

This diploma thesis deals with the topic of cheese analogues, their characterization and qualitative and quantitative analysis of processed cheese analogues for determination the taste and aroma active compounds. The overall character of processed cheese analogues is theoretically compiled in the introductory part. Their utilization, causes of the production, market introduction, technological production process and microstructure, including their comparison with classical processed cheese are given here. Various kinds of fats were used for production of analyzed cheese analogues, therefore commonly used ingredients for their production, their physical-chemical and sensory properties have been described. Specifically butterfat, milk fat, coconut fat, palm fat and mixed oil. Samples used for the practical part of the diploma thesis were made at Tomas Bata University in Zlín. In the experimental part the profile of aroma compounds in individual cheese analogues samples was assessed by SPME-GC analysis. In total 34 compounds were identified. The results were evaluated and compared, with emphasis put on the influence of storage, different fats, different maturity of Edam cheese on the content of aroma active compounds and on overall sensory quality of the analogues.

The HIV/AIDS pandemic has dramatically altered patterns of morbidity and mortality in sub-Saharan Africa during the last two decades. In the absence of HIV vaccine, microbicides may offer viable option for protection against HIV infection. Microbicides are products that are applied topically inside the vagina or rectum that act to impede transmission of HIV and other sexually transmitted diseases. Small human chemokines such as RANTES (regulated upon activation, normal T cell expressed and secreted) are currently been investigated as microbicides candidates. A number of N-terminally modified RANTES analogues such as 5P12 and 6P4 with a much higher antiviral potency have been developed and they have strong potential for use as microbicides. Since plants offer an alternative option for cost effective production of protein therapeutics, we evaluated the feasibility of expressing 5P12 and 6P4 in Nicotiana benthamiana species. 5P12 is considered the most promising candidate for use in the microbicide pipeline because it inhibits HIV infection through cellular receptor antagonism. Hence its feasibility of expression was also evaluated in Lycopersicon esculentum (tomato). The two analogues were transiently expressed in the selected plant species via agrobacterium-mediated transfection. For expression in N. benthamiana, two different vectors (pTRA and MagnICON) were used to deliver the two analogues for transient expression. About 6-8 weeks-old N. benthamiana plants were agroinfiltrated via needle injection and vacuum infiltration methods and targeted to four subcellular compartments viz: apoplast, chloroplast, cytosol and endoplasmic reticulum (ER). The agroinfiltrated leaves were replanted, grown in a tissue culture laboratory and harvested after different periods. For expression in L. esculentum, the MagnICON constructs were used to deliver the 5P12 gene into four different developmental stages of tomato fruits viz: mature green (MG), breaker (B), pink (P) and ripe (R) via needle injection. The agroinjected tomato fruits were incubated in a dark cupboard and harvested after different periods. xiii Proteins were extracted from the harvested material and evaluated for 5P12 and 6P4 expression. ELISA results showed expression of 5P12 and 6P4 in N. benthamiana leaves which was detectable at 3-9 days post infiltration (dpi). Similar results were obtained for 5P12 and 6P4, consequently only results for 5P12 are reported. The vacuum infiltrated leaves of both pTRA and MagnICON constructs led to higher yields than the needle injected leaves. The highest yields were obtained with the MagnICON constructs. The highest 5P12 expression level of 603 μg/kg fresh weight leaf tissues (~0.024% TSP) was obtained in the apoplast at 9 dpi. The pTRA constructs had the highest expression levels of 0.63μg/kg FW in the cytosol at 3 dpi. 5P12 was also detectable at 3-9 dpi in L. esculentum, based on ELISA results. The highest 5P12 expression of 23.56 μg/kg FW and pH 4.75 tissues was obtained at the MG stage in the apoplast at 9 dpi. Western blot analysis confirmed the size of plantmade 5P12. Moreover, the plant extracts had anti-viral activity and were not toxic to TZM-bl cells. Our results show that the RANTES can be made in both N. benthamiana and L. esculentum and that the levels are not different from other systems reported previously. Furthermore, this is the first report that a chemokine has been expressed in plants. The quantities expressed were low making the commercial development of a microbicide from these species impractical. However, production of bulky leaf material may enhance the quantities. / Thesis (PhD)--University of Pretoria, 2013. / gm2013 / Paraclinical Sciences / unrestricted

No description available.

No / The indoloquinoline alkaloid cryptolepine 1 has potent in vitro antiplasmodial activity, but it is also a DNA intercalator with cytotoxic properties. We have shown that the antiplasmodial mechanism of 1 is likely to be due, at least in part, to a chloroquine-like action that does not depend on intercalation into DNA. A number of substituted analogues of 1 have been prepared that have potent activities against both chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum and also have in common with chloroquine the inhibition of ß-hematin formation in a cell-free system. Several compounds also displayed activity against Plasmodium berghei in mice, the most potent being 2,7-dibromocryptolepine 8, which suppressed parasitemia by 89% as compared to untreated infected controls at a dose of 12.5 mg kg-1 day-1 ip. No correlation was observed between in vitro cytotoxicity and the effect of compounds on the melting point of DNA (¿Tm value) or toxicity in the mouse¿malaria model.

No / Morphological biosignatures (features related to life) and associated terrestrial sedimentary structures that provide possible sampling targets for the remote astrobiological exploration of planets have been analysed using Raman spectroscopic techniques. The spectral data from a suite of samples comprising crypto-chasmoendoliths, preserved microbial filaments and relict sedimentary structures comprise a preliminary database for the establishment of key Raman biosignatures. This will form the basis for the evaluation of prototype miniaturised instrumentation for the proposed ESA ExoMars mission scheduled for 2013. The Raman spectral biosignatures of carotenoids and scytonemin, organic biomolecules characteristic of the cyanobacterial colonisation of geological matrices and biogeologically modified minerals are also identifiable in the sedimentary specimen materials. The results of this study demonstrate the basis of the molecular recognition of extinct and extant exobiology that will feed into the elemental structural analyses of morphological structures provided by associated SEM, XRD and laser-induced breakdown spectroscopy (LIBS) techniques on robotic analytical landers.

no / Cryptolepine (5-methyl-10H-indolo [3, 2-b] quinoline), an indoloquinoline alkaloid (1) isolated from a medicinal plant traditionally used in Western Africa for treatment of malaria, has been shown to possess broad spectrum biological activity in addition to its antiplasmodial effect. Here, the antileishmanial properties of 11 synthetic derivatives of cryptolepine against Leishmania donovani parasites have been evaluated for the first time. 2,7-Dibromocryptolepine (8; IC50 0.5 ± 0.1 μM) was found to be the most active analogue against the promastigote form of a classical L. donovani strain (AG83) in comparison to the natural alkaloid, cryptolepine (1; IC50 1.6 ± 0.1 μM). Further, 8 was found to substantially inhibit the intracellular amastigote forms of two clinical isolates, one of them being an SbV-resistant strain of L. donovani. Moreover, the toxicity of 8 against normal mouse peritoneal macrophage cells was markedly lower than that of 1 (IC50 values: 9.0 ± 1.2 and 1.1 ± 0.3 μM, respectively), indicating 8 to be a prospective “lead” towards novel antileishmanial therapy. This was supported by studies on the mechanism of cytotoxicity induced by 8 in L. donovani promastigotes (AG83), which revealed the cytoplasmic and nuclear features of metazoan apoptosis. Light microscopic observation demonstrated a gradual decline in the motility, cell volume, and survival of the treated parasites with increasing incubation time. Flow cytometric analysis of phosphatidylserine externalization and distribution of cells in different phases of cell cycle confirmed the presence of a substantial percentage of cells in early apoptotic stage. Disruption of mitochondrial membrane integrity in terms of depolarization of membrane potential, and finally degradation of chromosomal DNA into oligonucleosomal fragments—the hallmark event of apoptosis—characterized the mode of cell death in L. donovani promastigotes.

No description available.

Malaria continues to cause significant mortality in sub-Saharan Africa and elsewhere, and existing vector control measures are being threatened by growing resistance to pyrethroid insecticides.  With the goal of developing new human-safe, resistance-breaking insecticides we have explored several classes of acetylcholinesterase inhibitors.  In vitro assay studies have shown that trifluoromethyl ketones (TFK's) are potent inhibitors of An. gambiae AChE (AgAChE), that inhibit the enzyme by making a covalent adduct with the catalytic serine of the enzyme.  However research in the Carlier group has shown that trifluoromethyl ketones bearing benzene and pyrazole cores have shown very little toxicity to An. gambiae, perhaps due to hydration and rapid clearance. Focus was directed towards synthesis of oximes, oxime ethers, and hydrazones as potential prodrugs to prevent immediate hydration and reach the central nervous system.  The synthesis of various oximes, oxime ethers, and hydrazones has been shown to give cimpounds toxic to Anopheles gambiae within 3- to 4-fold of the toxicity of propoxur. However, thus far we have not been able to link the toxicity of these compounds to a cholinergic mechanism.  Pre-incubation studies suggest that significant hydrolysis of these compounds to TFKs does not occur or 22 h at pH 7.7 or 5.5.   Future work will be directed towards TFKs that have better pharmacokinetic properties.  Work will also be directed at synthesis of oxime and hydrazone TFK isosteres to determine the mechanism of action of these compounds. / Master of Science

Les lymphocytes T Vγ9Vδ2 ont été étudiées depuis les années quatre-vingt pour leurs puissantes propriétés anti-infectieuses, démontrées aussi bien in vitro que dans des modèles animaux et confirmées par de nombreuses observations cliniques.L'implication de ces cellules dans l’immunité anti-infectieuse réside dans leur reconnaissance d’une famille de molécules produites par des pathogènes intracellulaires appelées phosphoantigènes dont l’activateur naturel le plus puissant à ce jour est le HDMAPP : (E)-1-hydroxy-2-méthylbut-2-ényl 4-diphosphate.Après avoir défini et synthétisé un synthon clé, sur lequel nous avons couplé des groupements pyrophosphonate et pyrophosphoramidate, nous avons réalisé des bioisostères de la molécule HDMAPP. Nous avons également synthétisé des isomères géométriques, analogue de position et isomères cis, des dérivés carbonylés, acide et ester. La bioactivité de ces molécules a été testée in vitro et pour les plus actives in vivo. Les résultats obtenus indiquent que l'utilisation de composés bioisostères de HDMAPP peuvent représenter de nouvelles pistes prometteuses pour l'immunothérapie. / Vγ9Vδ2 T lymphocytes have been studied since the early eighties for their potent anti-infectious properties, attested both in vitro and in animal models and supported by many clinical observations. The involvement of Vγ9Vδ2 T cells in anti-infectious immunity lies in their recognition of an original family of molecules produced by intracellular pathogens so-called phosphoantigens and whose most potent natural activator to date is the HDMAPP: (E)-1-hydroxy-2-methylbut -2-enyl diphosphate.Having defined and synthesized a key intermediate on which we have linked pyrophosphonate and pyrophosphoramidate moieties, we have made bioisosters of the molecule HDMAPP. We also synthesized geometric isomers, analogue of position and cis isomers, carbonyl derivatives, acid and ester. The bioactivity of these molecules was tested in vitro and for the most active in vivo. The results indicate that the use of bioisosters compounds of HDMAPP may represent promising new leads for immunotherapy.