Amongst the very many different kinds of amino sugars, theones that have aroused the most interest are the 2-amino 2-deoxy hexoses which are found in such well known antibiotics as streptomycin and neomycine (2). There are so far about forty-three antibiotics which are known to contain different aminosugars (6). Aminosugars exhibit the same properties as other reducing aldohexoses, e. g. reduction of silver and cupric salts, oxidation to hexonic acids, reduction to alcohols and formation of glycosides. The object of this project is to synthesize methyl N-acetyl α-D-talosaminide which has previously been prepared by Jeanloz (3) following a different route. The path that jeanloz, Jeanloz, and Glazer (3) followed involved the preparation of methyl 2-acetamide 4, 6-benzylidene 2-deoxy α-D-idospyradoside by ammonolysis of methyl 2,3-anhydro 4,6-benzylidene α-D-idospyranoside which was converted to methyl 2-acetamido 4,6-benzylidene talopyranoaide by treatment with sodium acetate in aqueous 2-methoxyethanol. This compound was debenzylidenated with aqueous acetic acid and acetylated to obtain methyl 2-acetamido 3,4,6-tri-0-acetyl talosaminide. In short, the above route involved essentially a direct conversion from the idose series into the talose series which is illustrated in Scheme I.

Titre de l'écran-titre (visionné le 11 janvier 2024) / La chimie des glucides a connu un essor dans les dernières décennies avec le développement de nouvelles méthodes de synthèses, de réactions et la compréhension des rôles essentiels des glucides dans différents systèmes biologiques. Ces nouvelles connaissances ont mené à la mise en marché de nouveaux médicaments pour le traitement de maladies et d'infections. Malgré qu'ils soient peu nombreux, plusieurs sont considérés comme essentiels par l'Organisation Mondiale de la Santé. Les études effectuées sur les glycopeptides et les glucides fluorés ont permis de nombreuses avancées pour le développement de sondes moléculaires à base de glucides et l'apprentissage de processus biologiques. Dans un objectif d'explorer le potentiel biologique des glycopeptides, une nouvelle méthode de synthèse de glycopeptides $C$-terminaux a été développée par une réaction d'aminolyse de peptides sur résine oxime. L'optimisation de la réaction a été effectuée à l'aide de composés modèles et la robustesse a été testée pour de nombreux groupements fonctionnels. Cet avancement a permis la préparation d'une chimiothèque d'analogues des lincosamides, une classe d'antibiotiques glucidiques. De plus, comme les lincosamides possèdent une activité antipaludique intéressante, des analogues hybrides entre la clindamycine, la chloroquine et la mortiamide D ont été synthétisés. Ces nouvelles molécules ont aussi été testées contre différentes souches du parasite $Plasmodium falciparum$ pour déterminer leur potentiel antipaludique. Puisque les réactions de glycosylation sont cruciales dans le développement de nouveaux médicaments à base de glucides, une nouvelle approche d'alkylation de la position anomérique de glucides fluorés a été développée. Lors de l'exploration de cette méthode, des analogues fluorés de l'étoposide, un agent anticancéreux, ont été synthétisés. Aussi, la synthèse d'un ʟ-nucléoside fluoré a été revisitée à partir du 2-désoxy-2-fluoro-ᴅ-galactopyranose; la clévudine (ʟ-FMAU). Cette dernière a été synthétisée en moins d'étapes et avec de meilleurs rendements. Deux étapes clés ont permis un accès facile au motif ʟ-arabinose : une cyclisation promue à l'iode et un clivage oxydatif. / Carbohydrate chemistry had a boom in the last decades with the development of new synthetic methods, reactions, and understanding of the essential roles of carbohydrates in various biological systems. This new knowledge has led to the marketing of new drugs for the treatment of diseases and infections. Although there are few, several are considered essential by the World Health Organization. The research carried out on glycopeptides and fluorinated carbohydrates has led to many advances for the development of carbohydratebased molecular probes and the learning of biological processes. With an objective to explore the biological potential of glycopeptides, a new method for the synthesis of $C$-terminal glycopeptides has been developed by an aminolysis reaction of peptides on oxime resin. Reaction optimization was performed using model compounds and robustness was tested for many functional groups. This advancement helps in the preparation of lincosamide analogs, a class of carbohydrate antibiotics. Moreover, as lincosamides possess interesting antimalarial activities, hybrid analogues between clindamycin, chloroquine and mortiamide D have been synthesized. These new molecules were also tested against different strains of the $Plasmodium falciparum$ parasite to determine their antimalarial potential. As glycosylation reactions are crucial in the development of new carbohydrate drugs, a new approach for alkylation of the anomeric position of fluorinated carbohydrates has been developed. While exploring this method, fluorinated analogues of etoposide, an anti-cancer agent, were synthesized. Also, the synthesis of a fluorinated ʟ-nucleoside has been revisited from 2-deoxy-2-fluoro-ᴅ-galactopyranose. Clevudine (ʟ-FMAU) was synthesized in fewer steps and in better yields with two key steps that allowed easy access to the ʟ-arabinose motif: molecular iodine-promoted cyclization and oxidative cleavage.

The aromatic beta-glucosides of plant origin, salicin and arbutin, serve as carbon sources for the sustenance of bacteria when ‘preferred’ sugars are absent in the environment. In the family Enterobacteriaceae, there are varied patterns for utilization of these beta-glucosides, wherein, in some members the ability to utilize salicin or arbutin is cryptic while in others it is completely absent. Escherichia coli harbors silent or cryptic genetic systems for the utilization of arbutin and salicin, which are activated by spontaneous mutation(s). Of these systems, the bgl operon of E.coli has been used as a paradigm for silent genes and extensive studies have been carried out to understand its silencing and activating mechanisms. Mutational activation of the wild type bgl operon in E.coli leads to the acquisition of the ability to utilize both arbutin and salicin. Preliminary studies have shown that aromatic beta-glucoside utilization in Shigella sonnei, which is evolutionarily related to E.coli, shows a two-step activation process wherein the wild type strain first becomes Arb+, which subsequently mutates to Sal+. The genetic systems responsible for beta-glucoside utilization, including the bgl operon, are conserved in S.sonnei to a large extent. A major difference is that the bglB gene encoding the phosphor-β-glucosidase B is insertionally inactivated in S.sonnei. As a result, activation of the bgl operon in the first stage leads to expression of the permease, BglF, which along with the phosphor-β-glucosidase A expressed from an unlinked constitutive gene, bglA, confers an Arb+phenotype. Salicin is not a substrate for the enzyme BglA and therefore a second mutational event is required for the acquisition of the Sal+ phenotype. Interestingly, the insertion within bglB is retained in AK102, the Sal+ second step mutant of S.sonnei. Therefore, the locus involved in conferring salicin utilization ability is unknown. However, S.sonnei is not amenable to routine genetic echniques and an E.coli bglB model was generated by creating an insertion in the bglB gene to identify the locus involved in conferring the Sal+ phenotype. Like S.sonnei, this E.coli strain, SD-1.3, also showed a two-step activation process for the utilization of salicin. Utilization of salicin in the Sal+ second step mutant of SD-1.3 could require activation of other silent genetic systems such as the asc operon and the chb operon or mutation in loci such as bglB or bglA. Linkage analysis by P1 transduction showed that activation of the asc operon is required for conferring a Sal+ phenotype in the second step mutant. The asc operon comprises of two genes, ascF encoding a PTS permease and ascB encoding a phosphor-β-glucosidaseB.The Precise mechanism of activation of the asc operon is not known but, it has been speculated that AscG, encoded by an upstream gene, acts as a repressor. Results presented in this thesis show that BglF is responsible for the transport of salicin and AscB provides the phosphor-β-glucosidase B in the Sal+ second step mutant of the E.coli strain SD-1.3. Analysis of the expression of the ascFB operon by measuring the transcripts as well as the activity of phosphor-β-glucosidase B showed that it is enhanced in the Sal+ second step mutant of SD-1.3 in the presence of the inducer. The expression of the ascFB operon is also increased constitutively when ascG is replaced by an antibiotic cassette in the parent strain SD-1.3 and the Arb+ first step mutant, indicating that AscG acts as a repressor for the asc operon. Moreover, inactivation of ascG in the parent leads to utilization of salicin in a single step by the activation of the bgl operon to provide the transport function, indicating that the inactivation of ascG is sufficient to activate the expression of ascB. Similarly, loss of AscG–mediated repression of the asc operon confers salicin utilization ability to the Arb+ first step mutant of SD-1.3. Interestingly, measurement of phosphor-β-glucosidase B activity in a Sal+ second step mutant derivative deleted for ascG showed a constitutive increase in the expression of the ascFB operon. Thus, AscG mediates the induction of the asc operon in response to salicin. In order to study the mechanism of activation of the asc operon, the ascB gene was cloned from the Arb+ first step mutant and the Sal+ second step mutant of SD-1.3 in a low copy number vector. Both these constructs were able to confer a Sal+ phenotype to the Arb+ first step mutant indicating absence of any genetic change in ascB in the Sal+ second step mutant. This was also confirmed by sequencing of ascB gene from the strains that showed no changes in the nucleotide sequence. Absence of any insertions within ascG showed that activation of the ascoperon is not achieved through disruption of ascG in the Sal+ second step mutants analyzed. AscG belongs to the GalR family of repressors in which some members require a mutation to enable the binding of sugar to mediate induction. Nucleotide sequence analysis showed that there was no change in the ascG gene in the Sal+ mutants analyzed. However, when the upstream regulatory region of the ascFB operon was analyzed a mutation was found in the -10 sequence of the putative promoter of the ascFB genes. This change leads to a stronger promoter as it brings the -10 sequence closer to the consensus sequence. Therefore, salicin utilization is achieved in the Sal+ second step mutant analyzed by an increase in expression of the asc operon by a promoter-up mutation. The negative effect of binding of AscG on expression of the ascFB operon is relieved in presence of the inducer, salicin. The possible role of the asc operon in salicin utilization in S.sonnei was tested by replacing the ascB gene by anantibiotic cassette in AK102, the Sal+ second step mutant of S. sonnei. This did not lead to loss of salicin utilization. By gene targeting approach it was also found that none of the phosphor-β-glucosidases known in E.coli are involved in degradation of salicin in AK102. A search of the S. sonnei genome database indicated the presence of two putative phosphor-β-glucosidases encoded by glvG and SSO1595. Replacement of glvG gene by anantibiotic cassette in AK102 did not lead to loss of salicin utilization. However, a similar replacement of SSO1595 in AK102 resulted in a Sal+ phenotype indicating that SSO1595 provides the phosphor-β-glucosidase in the Sal+ second step mutant of S. sonnei. A homolog of this enzyme is not present in E.coliorinany of the other members of the Shigella genus. Transcription alanalysis as well as measurement of phosphor-β-glucosidase B activity showed that expression of SSO1595 is enhanced constitutively in AK102. To study the mechanism of mutational activation for achieving salicin utilization in S. sonnei, SSO1595 was cloned from AK101, theArb+ first step mutant and AK102, the Sal+ second step mutant in a low copy numbe rvector. Both these constructs were able to confer a Sal+ phenotype to AK101 indicating an absence of genetic change in SSO1595 in AK102. This was also confirmed by sequencing of SSO1595 gene from the strains. Analysis of the upstream regulatory region of SSO1595 in AK102 indicated a deletion of around 1.0kbp sequence. This was also confirmed by nucleotide sequencing of the region. By primer extension analysis it was found that a new transcriptional start site is generated upstream to the deletion in the Sal+ second stepmutant of S.sonnei. Acquisition of the Sal+ phenotype in AK102 is therefore the resultof the SSO1595 gene being brought under a new promoter as a result of a DNA rearrangement. Overall, this study suggests that a high degree of similarity at the genomic level between organisms does not always ensure similarity in genetic mechanisms as two distinct pathways are responsible for conferring utilization of salicinin S. sonnei and E.coli.

Mémoire (M.Ress.Renouv.) -- Université du Québec à Chicoutimi, 1992. / Document électronique également accessible en format PDF. CaQCU

Mémoire (M.Ress.Renouv.)-- Université du Québec à Chicoutimi, 1994. / Résumé disponible sur Internet. CaQCU Document électronique également accessible en format PDF. CaQCU

A trealase solúvel foi purificada a partir do intestino de S. frugiperda. Os pKas dos grupos catalíticos determinados por inativação química são similares aos pKas determinados por analise cinética, indicando que a enzima tem um grupo carboxila que atua como um nucleófilo e um grupo guanidina que atua como doador de prótons. Dietil pirocarbonato não afeta a enzima, exceto na presença de MalfaGlu (inibidor competitivo). A modificação com DPC diminui a atividade enzimática da trealase e muda o valor do pKa do resíduo de Arg, indicando que o resíduo de His modula o pKa do doador de prótons. Trealase tem dois subsítios para a ligação de glicose e baseado na proteção por MalfaGlu durante a modificação química é possível inferir que o subsítio que liga MalfaGlu contém o grupo carboxila, e o outro subsítio possui o resíduo de Arg que atua como grupo catalítico e o resíduo de His. Usando diferentes estratégias nós obtivemos uma seqüência parcial do cDNA que aparentemente codifica para trealase (denominada trealase 1) e clonamos e expressamos a enzima denominada trealase 2. A trealase 2 foi expressa em Bl21 DE3 e purificada, sendo que suas propriedades são similares a enzima solúvel. O cDNA da trealase 1 provavelmente codifica para a trealase de membrana encontrada no intestino de S. frugiperda. A trealase 2 tem 587 aminoácidos, um pepitideo sinal com 23 aminoácidos e seis possíveis sítios para glicosilação. A enzima apresenta alta identidade e similaridade (61% e 76%, respectivamente) com a trealase digestiva de B. mori. Foi determinada a atividade de trealase presente na carcaça, Túbulos de Malpighi, corpo gorduroso, intestino e hemolinfa de Tenebrio molitor, Musca domestica, Spodoptera frugiperda e Diatraea saccharalis na presença e na ausência de ß-glicosideos tóxicos produzidos por plantas. Os glicosídeos usados foram amigdalina, prunasina, florizina e o aglicone mandelonitrila. E a atividade das trealases de T. molitor e S. frugiperda foi determinada também na presença de esculina. Prunasina é o melhor inibidor das trealases de T. molitor, já para as trealases (ligadas a membrana) de D. saccharalis o melhor inibidor é florizina e esculina é o melhor inibidor das trealases de S. frugiperda. Nós alimentamos S. frugiperda com uma dieta contendo 0,1% de esculina e sua presença nós tecidos foi detectada por fluorescência. Esculina foi encontrada no corpo gorduroso, Túbulos de Malpighi e hemolinfa e não foi encontrada na carcaça. A maior quantidade de esculina foi registrada na hemolinfa (0,2 mM) e as larvas alimentadas com uma dieta contendo esculina são 40% menor que as larvas alimentadas numa dieta controle. A inibição das trealases pode ser um dos fatores que leva a diminuição de peso das larvas experimentais. As larvas de S. frugiperda criadas numa dieta com 0,1% de amigdalina apresenta em alguns tecidos um aumento na atividade especifica de trealase o que não é observado quando as larvas são alimentadas com uma dieta com 0,1% de esculina. O aumento na atividade especifica de trealase pode ser uma das razões pela qual o desenvolvimento de S. frugiperda não é afetado pela amigdalina presente na dieta. / A soluble trehalase was purified from Spodoptera frugiperda midgut. The pKas of the catalitical groups determined by chemical inactivation agrees with the ones determined by kinetical analysis, indicating that the enzyme has a carboxyl group that acts as a nucleophile and a guanidine group that is the proton donor. Diethyl pyrocarbonate (DPC) does not affect to the enzyme, except in the presence of MalphaGlu (a competitive inhibitor). DPC modification decreases trehalase activity and changes the pKa value of the catalytical Arg residue, indicating that pKa of the proton donor His residue modulates. Trehalase has two subsites for glucose binding and based on the protection by MalphaGlu against chemical modification it is possible to infer that the subsite that binds MalphaGlu contains the catalytic carboxyl, whereas the other has the catalytical Arg residue and the His residue. Using different strategies we succeeded in obtaining a partial sequence of a cDNA that apparently codes for trehalase (called trehalase 1) and in molecular cloning and expressing the enzyme named trehalase 2. Trehalase 2, expressed in Bl21 DE3 cells was purified and its properties are similar to the soluble enzyme. Trehalase 1 cDNA probably codes for a membrane-bound trehalase found in S. frugiperda midgut. Trehalase 2 has 587 amino acids, a signal peptide with 23 amino acids and six possible sites for glycosilation. The enzyme present higher identity and similarity (61% and 76%, respectively) to digestive trehalase of Bombyx mori. Trehalase from body wall, Malpighian tubules, fat body, midgut and haemolymph from Tenebrio molitor, Musca. domestica, Spodoptera frugiperda and Diatraea saccharalis were assayed with and without the presence of toxic glucosides produced by plants. The glucosides used were amygdalin, prunasin, phlorizin and the aglycone mandelonitrile. In addition, T. molitor and S. frugiperda trehalases were assayed with esculin. Prunasin is the best inhibitor in T. molitor and M. domestica, phlorizin in D. saccharalis (only membrane-bound activity) and esculin in S. frugiperda. We fed S. frugiperda with a diet containing 0.1 % esculin and followed its fate by fluorescence. Esculin is recovered from fat body, Malpighian tubules and haemolymph. No esculin was found in body wall. The majority of esculin was recovered in haemolymph (0.2 mM) and larvae fed on esculin-containing diet weigh 40 % less than control ones. Trehalase inhibition by esculin may account for at least part of the observed decrease in larval weight. S. frugiperda larvae reared in 0.1% amygdalin-containing diet present higher trehalase activities in several tissues than the larvae reared in 0.1% esculin-containing diet. Higher trehalase activity should be the reason why S. frugiperda development is affected by esculin, but is not impaired by amygdalin present in the diet.

Endothelial dysfunction (ED) is associated with many cardiovascular conditions including hypertension and hyperhomocysteinemia. The decreased bioavailability of nitric oxide and increased oxidative stress are the hallmarks of ED. Apart from the mainstream Western medicine treatment, Chinese medical interventions have also demonstrated their capacity in dealing with a great variety of cardiovascular conditions. The effectiveness of acupuncture on hypertension has been recognized by the World Health Organization but the underlying mechanisms have hitherto remained largely obscure. A commonly prescribed Chinese herb, the Root of Rhodiola rosea has been used to treatment a wide range of cardiovascular conditions but its effect on ED is also unclear. In this thesis, we have explored the effects and the underlying mechanism of these two important Chinese medical interventions. / In the first part, we have performed an acupuncture study on hypertensive animals. Eighteen weeks old adult Wistor Kyoto Rats (WKYs) and Spontaneously Hypertensive Rats (SHRs) were divided into WKY control, SHR control, Sham-acupuncture and real acupuncture groups. Electroacupuncture was performed on acupoints ST36 and LR3 in the real acupuncture group for 6 weeks. The blood pressure at the end of the treatment was lowered in acupuncture group when compared with SHR control and sham-acupuncture group. Serum angiotensin II level in SHR controls was higher than that in WKY control and acupuncture treatment significantly attenuated it. Dihydroethidium (DHE) imaging showed that the reactive oxygen species (ROS) level was reduced in the aortas and carotid arteries of acupuncture treated SHR. Biochemical assays showed that acupuncture inhibited the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity and enhanced antioxidant capacity. In functional studies, the endothelial dependent relaxation of aorta rings and carotid arteries to acetylcholine were improved in acupuncture group. SHRs received acupuncture also expressed a elevation of eNOS and peNOS level and inhibition of nitrotyrosine level in Western blotting assay. The nitrate/nitrite level in aortic tissue was also increased by acupuncture. The findings concluded that one of the possible mechanisms of acupuncture in lowering blood pressure involved the improvement of oxidative stress, nitric oxide bioavailability and endothelium functions. / In the second part, we have studied the effects of salidroside, an active ingredient of the root of Rhodiola rosea with documented antioxidative, antihypoxia and neuroprotective properties on homocysteine induced ED. Functional studies on the rat aortas were performed to delineate the vascular effect of salidroside. Exposure to homocysteine attenuated endothelium-dependent relaxations in rat aortas while salidroside pretreatment rescued it. DHE imaging revealed that salidroside inhibited homocysteine-induced elevation in ROS production in both aortas and cultured endothelial cells. Western blot analysis showed that salidroside increased the phosphorylation of eNOS which was diminished by homocysteine in endothelial cells. Moreover, salidroside inhibited the NOX2 expression which was promoted by homocysteine in aorta tissue. The findings suggested that salidroside was effective in preserving the NO bioavailability and reducing ROS level, thereby protecting against homocysteine-induced impairment of ED. / We have successfully demonstrated the two Chinese medicine modalities, i.e. acupuncture and salidroside, a naturally occurring chemical compound isolated from Rhodiola rosea, delivered beneficial effects on ED, and both of them exert anti-oxidative effects for their action. Our experimental findings have enhanced the prospective of using Chinese medical interventions to manage oxidative stress-associated cardiovascular conditions and also helped put the clinical use of Chinese medical interventions on a more scientific footing. / 內皮功能失調與很多心血管系統疾病，包括高血壓和高半胱氨酸過高症有著十分密切的關系，一氧化氮供應減少與氧化應激增加均為這病理現象的一個特徵。除了主流的西方醫學治療方法外，中醫藥也一直表現出對各種心血管系統疾病有著明顯的療效。其中以針灸治療高血壓雖然己被世界衛生組織認可為一有效之療法，然而其療效原理卻並未被完全了解。另外，中草藥當中的紅景天，其對心血管疾病的療效亦非常顯著，唯其對內皮功能失調之影響卻仍有待查証。在這部論文當中，作者將會對以上兩項中醫藥治療方法的原理作出深入探討。 / 在第一部份的實驗當中，作者對自發性高血壓的大鼠施行了針灸治療。把十八週歲的自發性高血壓大鼠與京都種大鼠分為1)京都種大鼠對照組 2)自發性高血壓大鼠對照組 3)假針組針針刺組。針刺組中所使用的方案乃於足三里和太沖施行為期六週的電針治療。治療後針刺組的血壓相對於高血壓大鼠對照組和假針組均有明顯下降。同時針刺組大鼠血液中的血管緊張素II亦明顯降低。顯微鏡螢光造影發現於主動脈與頸動脈組織中，超氧化因子數量於針刺後均低於另外兩組高血壓大鼠對照組與假針組。另外實驗結果亦發現尼克酰胺腺嘌呤二核苷酸磷酸氧化酶的活動於針刺後下降，而抗氧化總容量則有所提升。另一方面，血管功能測試則顯示在針刺組內，由乙酰胆碱所引發的血管舒張比對照所產生的有所增加。而內皮一氧化氮酶和磷化皮內皮一氧化氮酶於血管中的表達則於針刺治療後有所增加，反觀硝基酪氨酸的含量則於針刺後減少。針刺對於血管組織中的亚硝酸盐/硝酸盐含量均有刺激作用。綜合而言，針刺能透過抑制氧化應激從而增加血管中一氧化氮的含量，最後達至內皮功能改善而降低血壓。 / 在第二部份，作者對中藥紅景天內其中一種活性成份紅景天苷對半胱氨酸所引起的內皮功能損傷進行研究。血管功能測試顯示半胱氨酸抑制了由乙酰胆碱所引發的血管舒張，而紅景天苷則能有效逆轉該抑制作用。顯微鏡螢光造影則發現紅景天苷能壓制由半胱氨酸所刺激的超氧化因子，另一方面能增加由半胱氨酸所抑制的磷化皮內皮一氧化氮酶的表達。尼克酰胺腺嘌呤二核苷酸磷酸氧化酶為超氧化因子的其中一個主要來源，半胱氨酸被發現會對其當中NOX2亞組的表達有刺激作用，而紅景天苷則能減少其表達。實驗結果顯示紅景天苷對半胱氨酸所引起的內皮功能損傷有顯著保護作用，其原理則與減少氧化因子從而增加一氧化氮的含量有密切關系。 / 整體而言，本論文成功顯示針灸與紅景天苷兩項中醫藥治療方案均能夠透過抑制超氧化因子而改善內皮功能捐傷。實驗結果加強了中醫藥於治療氧化應激相關的心血管疾病的應用，為中醫藥發展提供堅實的科學基礎。 / Leung, Sin Bond. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2014. / Includes bibliographical references. / Abstracts also in Chinese. / Title from PDF title page (viewed on 01, November, 2016). / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.

by Jing Xian Li. / Thesis (Ph.D.)--Chinese university of Hong Kong, 1998. / Includes bibliographical references (p. 137-151). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

No description available.

Lic.-avh. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2004. / Härtill 3 uppsatser.