In the past decade Arabidopsis thaliana has become an important system for studying meiosis in flowering plants. The identification of meiotic mutants has provided an important approach to studying plant meiosis. The availability of the Arabidopsis genome sequence together with developments in proteomics and bioinformatics provides an additional route for the identification of meiotic proteins and analysis of their functional interrelationships. This study has used a proteomics approach to identify a member of the SWI2/SNF2 chromatin remodelling gene family (Atchr24). Although a variety defects was observed in Atchr24 male meiocytes cytogenetic, at least two T-DNA insertion lines on this gene appear normal. Secondly, this research has also used a bioinformatics approach to identify a potential orthologue of Pch2/TRIP13 in Arabidopsis. PCH2 (Pachytene checkpoint 2) is a member of the AAA+ ATPase family of proteins. This study reveals that AtPCH2 plays an essential role in the controlled formation of meiotic crossovers (COs). Cytogenetic analysis of two Atpch2 T-DNA insertion lines revealed a high frequency of univalents at MI. The number of chiasmata (COs) is reduced to ~ 70% of wild-type (WT). Genetic analysis revealed that Atpch2 has significantly weaker CO interference than WT leading to a redistribution of COs along the chromosomes. The recombination defect is accompanied by incomplete chromosome synapsis. Immunolocalisation of the chromosome axis protein AtASY3 and cohesin, AtSYN1 appears normal. However in contrast to WT, AtASY1 co-localises with the synaptonemal protein AtZYP1 in ii Atpch2 rather than becoming depleted in regions of synapsis and the meiotic progression of Atpch2 is delayed during pachytene by ~5 hours. These observations suggest a defect in remodeling of the chromosome axes and highlight how this process is essential for normal CO control.

Cancer and malaria are among the most life-threatening diseases globally. Cancer is responsible for about 125,000 annual deaths globally. In 2015, the World Health Organization report estimated that 236000-635000 people died of malaria. These diseases are complicated by the development of resistance to available chemotherapeutic agents. Natural products have been recognized for their major applications in the identification of drug leads in drug discovery. Viola philippica Car, Viola yedoensis Makino (Violaceae), Triclisia subcordata Oliv (Menispermeaceae) and Cyclicodiscus gabunensis Harms (Fabaceae) are medicinal plants traditionally used for the treatment of various diseases including malaria or cancer in China and West Africa. However, the bioactive compounds are unknown. Therefore, this study evaluated the in vitro anticancer and antimalarial activities of the four medicinal plants and searched their bioactive compounds. The in vitro anti-ovarian cancer and antimalarial assays were demonstrated respectively using sulforhodamine B dye and Syber green 1 fluorescence assay methods. Bioassay-guided fractionation and purification were performed. Structural elucidation was performed by nuclear magnetic resonance spectroscopy and mass spectrometry analysis. Results revealed the anticancer and antimalarial activities of T. subcordata; V. philippica, and V. yedoensis to be bisbenzylisoquinoline alkaloids (cycleanine, isochondodendrine and 2′-norcocsuline) and/or cyclotides. The cycleanine analogues were synthesized and found to be more potent than cycleanine. Induction of apoptosis by these alkaloids has also been determined. This study could serve as basis for the support of use of these plants in cancer and/or malaria treatment. The BBIQ alkaloids and analogues could serve as lead compounds in drug discovery. Future in vivo studies need to be carried out on these alkaloids to get drug approval.

Melaleuca alternifolia (Tea tree oil) is commonly used by the general public in the treatment of superficial dermatological conditions. There is a growing body of evidence to support its use as an anti-fungal and anti-bacterial agent. However, there is little evidence of the in vivo penetration of components of the oil through the skin, imperative to ensure its use is directed appropriately and safely. Furthermore the extent of TTO’s ability as an anti-inflammatory agent and its potential mode of action are not know. This thesis describes the adaption and validation of the method in vivo dermal microdialysis in order to identify and quantify components of tea tree oil present at the dermal epidermal junction following the topical application of 100% TTO. In vitro investigations identified that the addition of hydroxypoply –β-cyclodextrin to the perfusate, the adjustment of flow rate and the use of cuprophan membranes ensured optimal recovery of components. Furthermore tape stripping was utilized to identify components present within the stratum corneum (SC). These methods were coupled with gas chromatography-mass spectrometry and were successful in the identification and quantification of terpinen-4-ol, 115.64±28.1 (ng±SEM) and 1,8 cineole, 15.05±2.6 at the dermal epidermal junction (n=10). Also the presence of 9 hydrophilic and lipid components (overall subjects) were observed within this top layer of epidermis (n=7). In addition the potential anti-inflammatory action of TTO and its component T-4-ol is investigated in vitro using the HaCaT cell line (model keratinocytes) including exploration of a potential mode of action. An inflammatory action was induced using lipopolysaccharide (LPS) and the cell supernatant analysed using the MSD™ electronchemiluminesence assay. A statistically significant increase in the release of IL1β was observed when non-stimulated HaCaT cells were incubated with TTO (not T-4-ol alone), compared to control (medium alone). Furthermore a statistically significant increase in IL6 was observed when non-stimulated HaCaT cells were incubated with TTO and T-4-ol compared with the incubation of stimulated HaCaT cells with the oil and its component. Investigation into the effect of TTO and T-4-ol on the transcription factor NFқB demonstrated that the oil and its component did not exert its effect by initiation of this pathway. The findings of this research have implications for clinical practice, particularly in the use of TTO on areas of dermatological inflammation and its use on ‘healthy’ skin.

The rapid development of seriously drug-resistant pathogen strains has created a dangerous problem to public health. The discovery of new effective antimicrobials remains an urgent task to control microbial resistance. Natural products can offer special stereochemistry and unlimited diversity of natural leads which are biologically active or ready for development and structure optimization strategies. Four medicinal plants Cylicodiscus gabunensis (CG), Pogostemon cablin (PC), Perilla frutescens (PF) and Magnolia biondii (MB) were selected for investigation of their phytochemical composition and antiplasmodial and/or antibacterial properties. A bioassay guided fractionation method has been followed to characterize the antiplasmodial and antibacterial constituents of CG. Flash column chromatography and preparative HPLC were used to obtain the bioactive compounds. GC-MS, LC-MS, and NMR have been used for chemical analysis purposes. For evaluation of the antibacterial activity, disk diffusion assay, alamar blue microplate assay, time kill kinetic and scanning electron microscopy (SEM) methods have been used. The work led to the isolation of the most potent antiplasmodial fraction of CG with IC50 of 4.7.

This study investigate the effects of four Chinese herbs for their potential therapeutic use as analgesics. It involved screening for inhibitors of enkephalin-hydrolysing enzymes, especially selective NEP inhibitors, mixed NEP/APN inhibitors and mixed NEP/ACE inhibitors. NEP was the key enzyme in the screening systems. Four Chinese herbs Yan (Corydalis yanhusuo T. Wang); Gou (Nauclea sinensis Oliv. ); Qiang (Notopterygium incisum Ting ex H.T. Chang); and Chuan (Ligusticum chuanxiong Hort.) were tested for their inhibitory effects on NEP activity measured in a rat kidney extract. Aqueous extracts of Gou and Qiang showed the significant inhibitory activity on NEP but results with organic extracts were not significant. Gou showed the strongest inhibitory activity on NEP. It was found that Gou also showed an inhibitory activity on the other two enkephalin-hydrolysing enzymes, APN and ACE in the microsomal mixture. A rat-brain opiate-receptor preparation (section 5.2.1) was used in ligand binding experiments with competition for the receptor sites between the aqueous Gou extract and tritium-labelled naloxone. For very small quantities of Gou there was a lowering of naloxone binding showing the antagonistical action of Gou. At higher concentrations (> 4 mg/ml of Gou) there was a tendency for naloxone binding to increase demonstrating potential agonistic activity. To test whether one compound in Gou had inhibitory activity on the three enzymes, or several compounds acting together, the aqueous extract of Gou was separated by HPLC. The HPLC-eluted fractions were pooled into seven parts and collected. The seven eluates were assayed for their effects on NEP proteolysis of 3H(leu)- enkephalin. Only six eluates showed inhibitory activity on NEP. The three single compounds already fractionated by others (rhynchophylline, mitraphylline and poteropodine) were shown to correspond in the Pool 7. An unexpectedly large number of active fractions suggest that many active compounds are present in Gou. It can be concluded that of the four herbs tested Gou (Nauclea sinensis Oliv) offers considerable potential as a novel analgesic agent. The work described in this dissertation was carried out in the School of Biomolecular Science, Liverpool John Moores University from October 1994 to May 1999. Unless otherwise stated it is the original work of the author. This dissertation has not been submitted, in whole or in part, for any other degree at this or any other university.

Herbal medicine has experienced tangible revivals in both Vietnam and the United Kingdom since the mid-20th century, as reflected in sales of herbal medicinal products, numbers of users and the availability of training opportunities for aspiring herbalists. In both countries, this revival came on the back of more or less concerted official efforts to discourage and even ban the practice and use of herbal medicine, by colonial authorities (in Vietnam) or professional medical associations and regulatory bodies (in the UK). Utilising archaeological and genealogical methods as developed by Canguilhem, Foucault and others, this study seeks to account for these revivals by pursuing three particular lines of analysis. Firstly, by describing the formations of power-knowledge relations which have allowed Vietnamese and British herbal medicine to challenge biomedical monopolies in the latter half of the 20th century, it is argued that the ways in which ‘quackery’ is conceptualised and regulated against in both countries today, has undergone substantial transformations. Secondly, by identifying the techniques of truth making which either suggest or contest a superior efficacy (over placebo) for two particular herbal medicines in the treatment of depression (in the UK) and addiction (in Vietnam), the study demonstrates how the concept of ‘efficacy’ not only pertains to bio-physiological effects but also to the symbolic effects of the treatments in question. Finally, by asking what kind of ‘life’ herbal medicine is seen to be affecting, it is suggested that longevity has been joined by quality of life as a separate, yet inherently interlinked, therapeutic site. One of the key conclusions of the dissertation is, that the sub-disciplines of medical anthropology and sociology have played a crucial role in the 20th century births of ‘traditional medicine’ and ‘complementary and alternative medicine’ (as opposed to ‘primitive’ and ‘fringe’ medicine). Firstly, in diagnosing a ‘crisis of modern medicine’ by highlighting its dehumanising and toxifying effects, and secondly, in providing a theory of symbolic efficacy which could help explain the continued importance of what had in the past been written off as ‘esoteric’ or ‘backward’ healing practices. As a consequence, the study describes how an ongoing governmentalisation of human subjectivities has been a requisite side effect of modernisation in the recent revival and renaissance of herbal medicine in Vietnam and the United Kingdom.

This thesis analyses how Andean people’s knowledge of medicinal plants and the relationship between environment and health is represented, transmitted and commoditised in the marketplaces of the department of Oruro, Bolivia. Considering the increase in urban population and their dependence on marketplaces for medicinal plant remedies, this thesis examines the role of marketplaces and the importance of specialist stallholders in the transmission of knowledge. The central research site of Oruro is a multi-cultural city located on the Andean plateau in southwest Bolivia, a population of Spanish, Quechua and Aymara speakers with a pluralistic medical system. Fieldwork was carried out over 18 months with market stallholders in Oruro combining quantitative and qualitative methods with ethnographic documentation of knowledge transmission events. This thesis found that medicinal plant marketplaces in Oruro are highly regulated social systems that incorporate Andean socio-economic mechanisms, including ritual performance for the transmission of cultural knowledge, and the regulation of resource distribution and use. The development of a ‘chemical landscape’ model demonstrated that social exchange and trade between ecosystems and altitudinal zones broadens the spectrum of medicinal compounds available, contributes to the complexity of herbal mixtures and can limit exploitation of local plant populations. The market stallholders use specialist classifications that identify chemical properties, toxicity and variations between plant species and ecological regions. Plant classifications varied with the context and location in which they were used, and humoral classification enabled the selection and combination of plants in mixtures and justified remedy efficacy for specialists and non-specialists. Andean cultural beliefs including complementary opposites enabled transmission of knowledge on the medicinal properties of plants between highland consumers and lowland producers, and defined traditional Andean mixture efficacy. These findings demonstrate that, although state intervention and identity politics are redefining perceptions of medicinal knowledge, the market exchange system centred in Oruro city creates localised specialist knowledge and continuity of cultural knowledge transmission.

No description available.

SYN1 is a meiosis-specific Arabidopsis homologue of yeast REC8. REC8 is an important component of the meiotic cohesion complex which maintains cohesion between sister chromatids. Cytological analysis of syn1\(^{-/-}\) has shown chromosome fragmentation at metaphase I. To determine the basis of chromosome fragmentation in the syn1\(^{-/-}\), three double mutants were constructed. I have demonstrated that chromosome fragmentation in syn1 is AtSPO11-1-dependent. Moreover, I have also shown that SYN1 has a role in DSB repair by analysing Atdmc1\(^{-/-}\)/syn1\(^{-/-}\) meiocytes. To investigate this further, immunolocalization studies in wild-type and syn1\(^{-/-}\) were conducted. Distribution of ASY1 and AtZYP1 was affected in syn1\(^{-/-}\). Both proteins appeared as aggregates, developing into an abnormal short linear signal in early prophase I, suggesting that both axis formation and synapsis are compromised. Distribution of the recombination proteins AtRAD51 and AtMLH1 was also aberrant. Localization of SYN1 in wild-type nuclei revealed a continuous signal along the chromosome axes. However, careful inspection revealed that this was accompanied by patches of more intense signals, possibly corresponding to DSB regions. To investigate this further I analysed SYN1 distribution in an Atspo11-1-4\(^{-/-}\) mutant. Whilst faint SYN1 signals were apparent along the axis, no patches of intense signals were visible. Cisplatin-induced DSBs restored AtZYP1 foci in Atspo11-1-4\(^{-/-}\) and also resulted in restoration of intense patches of the SYN1 signals. This is consistent with the recruitment of SYN1 to DSB sites.

Background. The growing population of migrants (including sub-Saharan Africans) in the United Kingdom poses challenges to British general practice. First, migrants tend to seek health care at times of crisis rather than for preventive measures. This is despite being at increased risk of certain chronic conditions compared with the indigenous population. For sub-Saharan Africans this includes hypertension-related diseases and some cancers. Little has been published about Africans’ awareness of this risk or their knowledge of associated causative factors. Second, discordant health beliefs and healthcare expectations between migrants and doctors in the UK have been found to undermine trust during consultations with general practitioners and to lead to poor patient satisfaction. Little is known about the health behaviours of African migrants whose expectations are not met by primary care in the UK. A related area where health beliefs and practices differ between African migrants and their GPs is in the use of traditional medicines. A final challenge lies in considering the wider issues that GPs must address when consulting with migrant patients, including time pressures, organisational factors and the complex nature of problems presented by migrant patients. These issues are the focus of this study. Aims. To examine African migrants’ perceptions of chronic disease and their experience of seeking primary health care in the UK. To explore the impact upon GPs of caring for migrants. Objectives. To explore: 1) perceptions of chronic disease risk facing African migrants and their underlying explanatory models; 2) experiences of consultations about antibiotic prescriptions; 3) traditional African medicine use in the UK; and (4) to consider the effect of workload and work patterns on GP consultations with migrants. Design. In-depth interviews were conducted with 19 Africans from French- or Swahili- speaking countries, one African key informant and 13 GPs working with migrants. African participant recruitment was from community organisations and GPs were approached via an informal network of doctors. Interviews were transcribed and ten were translated by the principal investigator (three Swahili and seven French). Data analysis was undertaken following the approach of applied thematic analysis using the Nvivo software package. Data collection and analyses were underpinned by the following theoretical frameworks: Kleinman’s explanatory models of illness and of cultural health care systems and Lipsky’s street-level bureaucracy. Results. Narratives suggested low awareness of chronic disease risk amongst Africans. Infectious diseases were considered the dominant health threat for African migrants, mainly HIV but also tuberculosis and ‘flu’. Chronic diseases were sometimes described by Africans as contagious. Explanatory models of chronic disease included bodily/dietary imbalance, stress/exertion, heredity/predisposition and food contamination. Cancer was feared but not considered a major threat. Cancer was considered more common in Europe than in Africa and was attributed by Africans to chemical contamination from fertilizers, food preservatives and industrial pollution. Evidence cited for these chemicals was rapid livestock/vegetable production, large size of farmed products (e.g. fish), softness of meat and flavourless food. Chemicals were reported to circulate silently inside the body and cancer to develop in the part where they deposit, sometimes years later. Africans’ belief in infective explanations of disease extended to minor illnesses and was manifested in an expectation of antibiotics from GPs for problems such as a sore throat. This arose from participants’ experience in Africa, witnessing life-threatening infectious diseases and experience of unregulated access to antibiotics. Africans described various alternative measures to fulfil their unmet expectations, including approaching other National Health Service doctors, importing medication, and using private healthcare services in London, francophone Europe and east Africa. A further option was the use of traditional African medicine, reported by one quarter of African participants. Traditional African herbal medicine use was based upon a perception of its purity and natural origin in African soil and a deep belief in its efficacy. Consulting traditional African healers in the UK was reported to be undertaken in secret. Some GPs and Africans described consultations in terms of pressure, processing and conflict. Migrants were reported to present with complex health problems that were frequently compounded by language barriers. GPs described a need to remain in control of consultations and this included some use of personal discretion to render their tasks easier to complete. The most common example was accepting patients’ family and friends as informal interpreters – a choice that ran contrary to formal policy of only using professional interpreters. Burnout was reported to be one consequence of excessive workload for patient-centred GPs working with vulnerable groups like asylum seekers. Conclusions. There is a need to improve health literacy amongst African migrants in order to promote preventive behaviours for chronic disease and alternatives to antibiotics for minor illnesses. As part of this, further research is required into the use and properties of traditional African medicine. Interventions should be built upon participants’ existing knowledge of disease causation, their self-reliance in the pursuit of a healthy lifestyle and desire to retain cultural practices. One challenge to improving migrant health lies in the service dilemmas facing GPs, including excessive workload, the complex nature of migrants’ presenting problems and professional dilemmas. GPs who act as advocates for vulnerable migrant patients may be at increased risk of burnout and greater consideration should be given to providing them with appropriate support.