This thesis reviews the first step in a project which will address the impacts that substandard housing has on the health and education of first nations residents. This thesis covers the findings from home inspections at a First Nations Community (FNC). In 2012, 159 homes were inspected. The inspection was visual and looked for mould and other deficiencies in the homes. Measurements of the interior air were also taken. Homes were substandard due to poor building materials, installation, and overall neglect regarding maintenance. Homes had high mould counts and are unhealthy environments for people. This thesis outlines common deficiencies and provides recommendations for the rehabilitation of the homes, and for future construction. Recommendations include that homes be built with durable materials, designed for their environment, and for education and training regarding home maintenance to be provided. Subsequent phases of this project will address the health and education of the residents.

The issue of how to ventilate the crawl space of buildings is often debated, since it affects both heat loss and humidity conditions, where the latter is crucial for the onset of mould growth and other microbiological activities. In this moment, experiments are going on in a historical stone church (Hamrånge church, Sweden), where crawl space air is leaking into the church hall, thus affecting heating requirements, air quality and the thermal comfort for visitors. The experiments include long-term field measurements and computer control of ventilation dampers, installed in order to attain a more favourable natural ventilation in the crawl space. The thesis work consists of analysing the above mentioned issues for this unique case.Nowadays this church has a Humidity Controlled Natural Ventilation. It works comparing Absolute Humidity between indoors and outdoors and depending on it, the dampers placed on some of the crawl space vents open or close themselves to let air go through them.The aim of this thesis is to analyse with all the data provided (taken from Hamrånge church) if a crawl space of the church already described is well ventilated or on the contrary it is not well ventilated. This thesis is not a computer simulation one but it is a data treatment one, analysis from data taken from this church will be done. Also it will be focused on the functioning of the control of the ventilation system to check how representative is where the sensor is placed to open and close the dampers. Besides, energy used in heating of one winter with this way to ventilate the crawl space will be compared with other winters when these devices were not used and vents were opened always.The methodology for the analysis will be performed taking advantage of the computer program Excel to be able to manage all the amount of data. A method taken from other authors will be used in order to study the mould growth risk in the crawl space and also some other studies of the variation of the Temperature, Absolute Humidity and Relative Humidity in the crawl space wile dampers are closed or open. Besides a method to analyse wind direction and speed will be implemented.As a result, after implementing all the analysis, this report will be concluded that this new method is well implemented with good results in terms of heating savings compared with other winters. Besides, although mould is a problem, the place where the sensor to open and close the dampers is the best one among the crawl space which is the one where more mould is expected during summer (from June to September), that is the season of the year when more mould and sooner is expected according with the results.

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The genome of the eukaryotic slime mould <i>Physarum polycephalum</i> contains highly methylated (M+) regions, 20-50kb long, which are resistant to cleavage by methylation sensitive restriction endonucleases. The major sequence comprising the M+ component is an abundant family of repetitive DNA sequences: Tpl elements. Members of the Tpl family are around 8.6Kb in length and have a number of structural characteristics in common with eukaryotic retrotransposons. The direct long terminal repeat (LTR) sequences defining the ends of Tpl elements are a typical feature of well-characterised eukaryotic transposons. The similarity extends to the ends of the LTRs, which are terminated by short inverted repeats. The present study describes some of the properties of the transposon-like Tpl family. Sequence analysis of cloned segments of copies of Tpl has allowed partial characterisation of the element at the nucleotide sequence level. In addition, novel sequence arrangements are described which may represent variant forms of Tpl or could indicate the presence of other, previously unidentified, repetitive sequence families in the <i>Physarum</i> genome. Tpl elements are arranged in scrambled clusters which are believed to have arisen by transpositional insertion of the element into copies of its own sequence. Several putative target sites for transposition have been identified and found to be clustered in specific regions of the Tpl sequence. These sites bear some resemblence to the Chi sequences found in bacteriophage lambda, thus suggesting an alternative mechanism for the rearrangement of Tpl sequences, i.e. homologous recombination. A study of the replication and transcription of Tpl elements was also initiated. The timing of replication during the cell cycle was determined using synchronous plasmodial cultures. Tpl elements were found to replicate at between 60 and 90 min into S-phase. Thus, they are contained within the relatively late-replicating fraction of the genome. Tpl elements were found to be transcribed in amoebae and plasmodia and could be the first examples of late-replicating <i>Physarum</i> sequences which are transcriptionally active. Some evidence of developmental regulation of expression of Tpl elements was also found. The similarity with retrotransposons suggested that an RNA intermediate may be involved in transposition. However, no full-length transcript was detected in this study.

Assays based on a biological response (bioassays) offer the possibility of screening foodstuffs for both known and uncharacterised mycotoxins. The sensitivity of several bioassays, namely brine shrimp, rat liver cells, baby hamster kidney cells, Bacillus megaterium, B. stearothermophilus Tetrahymena pyriformis and pea seedlings, to mycotoxin standards was established. Based on these results, the bacterial assays were found to be relatively insensitive to the majority of mycotoxins tested. A biological screen consisting of the above bioassays (excluding the bacterial assays) was capable of detecting twelve mycotoxins. This screen was applied to the testing of moulds isolated from mould-spoiled foods, identified, and tested in a ratio corresponding to their percentage occurrence. They included species of Aspergillus, Penicillium, Cladosporium, Rhizopus, Mucor, Alternaria and Wallemia. Approximately 60% of the moulds, when grown in culture media, caused a toxic effect in three or more of the bioassays. Some of the moulds caused enhanced toxicity when grown on a foodstuff; other extracts from mould-inoculated foods were found to be non-toxic to the bioassays. It was of interest to note the toxicity to bioassays caused by moulds such as Mucor and Wallemia. These are not well-recognised mycotoxin producers. A further study was made on toxin production by Wallemia. A scheme of chemical purification, involving TLC and HPLC, linked with bioassay testing, was used to isolate the toxic compound. The toxin, to be named walleminol A, has a molecular weight of 236 and probable composition of C15-H24O2. The minimum inhibitory dose of the toxin to bioassays was approximately 50 mug/ml. Toxicity of ochratoxin A to cell lines was not enhanced by the inclusion of microsomal enzymes. The acute toxicity of aflatoxin B1 and sterigmatocystin, was, however, greatly enhanced by the microsomal enzymes. Aflatoxin B1 and sterigmatocystin were metabolised to form the more polar metabolites. The effects of these toxins on cells was also examined by flow cytometry. This demonstrated that aflatoxin B1 and sterigmatocystin had no effect on the cell cycle unless activated by microsomal enzymes. The activated toxins inhibited DNA synthesis and showed that apparently surviving cells died on subculture.