Thesis (M.S.)--University of Montana, 2007. / Title from title screen. Description based on contents viewed July 24. 2007. Includes bibliographical references (p. 109-114).

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Maize (Zea mays L.) is an important cereal world-wide, serving as seed for growers, food for man and livestock as well as an industrial raw material. Unfortunately, it is also a suitable substrate for growth, development and activity of spoilage fungi. Fungal growth is a major problem in cereal grains throughout the world and may lead to poor quality of the products, as well as adverse effects to human and animal health due to mycotoxin production. Maize is usually harvested at high moisture content and then dried to bring down the moisture content to a safe level before storage. Delay in drying to safe moisture levels increases risks of mould growth and mycotoxin production. In rural villages maize is dried using only sun drying and they rely on sacks, thatched silo and drums as their storage facilities. This is insufficient to prevent damage by insects, rain, and rodents, which in turn allows fungi to invade these storage facilities. Maize was sampled in two rural areas of Venda (Limpopo Province) and the percentage moisture content was determined and then screened for total fungal contamination. The samples were also analysed for mycotoxins that have been reported to commonly occur in maize. There was no significant difference in the extent of fungal contamination in Mapate and Folovhodwe villages. Of the fungal species detected, Aspergillus species were the most common with Aspergillus flavus being the most predominant. On analysis by the multi-mycotoxin screen, aflatoxin had the highest incidence amongst mycotoxin, followed by T-2 toxin. However on using the VICAM method of analysis aflatoxins, deoxynivalenol and fumonisin were the most predominant mycotoxins in the samples, while zearalenone toxin was also amongst predominant mycotoxins but with the highest level of 0.1 ppm. Most of the mycotoxin-containing extracts were found to reduce the % cell viability of human lymphocytes, after 24 hours of incubation as determined by the methyl thiazole tetrazolium salt assay. vii In conclusion the co-occurrence of these toxins in maize and maize meal may highlight the problems associated with the intake of numerous toxins that could in turn lead to more adverse health effects such as liver, oesophageal, breast and cervical cancer, male reproductive tract damage and gynacomastasia. There is, therefore, need to disseminate information to these people, using simplified methods such as programs on radio and televisions on mycotoxin hazards and discussion on the issue should also feature regularly on daily newspapers and magazines, about the dangers and management aspects of mycotoxins, and the susceptible produce. / Prof. M. F. Dutton Mr. F. E. van Zyl

D.Tech. (Biomedical Technology) / To determine the quality of human food commodities commonly consumed in Cameroon, various districts in the western highland (Bamenda and Kumbo) and tropical rain forest (Douala and Yaounde) regions were sampled. Two mycological investigations were conducted to evaluate the incidences of mycotoxigenic fungi (95 samples) and mycotoxins (82 samples). Serial dilution of ground samples was employed to isolate fungi, subculture on various culture media and fungal species were identified morphologically followed by molecular phylogenetic approach. In general, data obtained indicate samples from various geographical regions showed no consistent variation with regard to the type of fungal species. The mycobiota of food materials were characterized by a diversity of fungal species with the predominance of Aspergillus (125 isolates) followed by Penicillium (94 isolates) and Fusarium (52 isolates). The less predominant genera include Rhizopus (14 isolates) and the Alternaria (9 isolates). Aspergillus flavus and A. parasiticus occurred in 53 and 44% of the samples, respectively, with higher frequencies in maize than peanuts or beans and absent in rice, pumpkin seed and cassava products. Aspergillus fumigatus was detected in 20% of samples and A. niger in 18% of the samples. Aspergillus isolated less frequently included A. carbonarius A. awamori, A. oryzae and A. tamarii, A. pseudotamarii, A. ochraceus, A. ostianus, A. avenaceum, A. oryzae and A. variabile. Consistent results were observed for A. tamarii, A. pseudotamarii, A. ochraceus and A. ostianus with respect to substrate specificity. While A. tamarii, A. pseudotamarii and A. ochraceus were isolated only from peanuts, A. ostianus strains occurred only in bean samples. Penicillium contamination was dominated by P. polonicum and P. crustosum with incidence rates of 43 and 41%, respectively, with highest contamination levels registered in samples from Yaounde. Penicillium citrinum, P. purpurogenum, P. islandicum, P. aurantiogriseum, P. expansum were also inconsistently isolated from food samples. There was a relatively low incidence of Penicillium spp. in pumpkin seed and fermented cassava product samples.

Le contrôle de l'aérocontamination fongique est devenu un objectif majeur pour préserver la santé humaine et animale. L'évaluation de l'aérocontamination fongique fait classiquement appel aux techniques de mise en culture ou de dosage de composants fongiques présents dans l'air. Ces techniques présentent des inconvénients. C'est la raison pour laquelle, nous nous sommes fixés comme objectif de mettre au point des méthodes d'analyse alternatives utilisant des outils de biologie moléculaire. Dans un premier temps, nous avons comparé plusieurs techniques de prélèvements d'air dans des environnements intérieurs présentant une contamination plus ou moins élevée. Nous avons, par la suite, optimisé les conditions d'extraction de l'ADN fongique à partir de prélèvements d'air. L'ADN extrait a été amplifié par PCR à semi-nichée ? avec des amorces universelles permettant d'amplifier une partie de l'ARNr 18S de champignons. Par la suite, nous avons utilisé la TTGE (Temporal Temperature Gradient Electrophoresis) et la D-HPLC (Denaturing High Performance Liquid Chromatography) pour séparer les amplificats. Chaque produit de PCR a été identifié par séquençage direct après purification. La comparaison des espèces identifiées par ces techniques avec celles qui sont obtenues par la méthode classique (culture) apporte de meilleurs renseignements sur la qualité fongique d'un même prélèvement d'air. L'application de ces techniques dans des environnements à diff'rents niveaux de contamination a permis de déduire que l'étude de l'évaluation de l'aérocontamination fongique se fait par l'association de la culture et des méthodes moléculaires / Fungal spores represent a significant part of the biological contaminants that could be detected in air. Exposure to fungi has been associated with several types of human or animal health problems (mycosis, allergy, mycotoxicosis). To evaluate the relationship between airborne fungi potential and adverse health effect, the fungal types and their relative frequencies in air need to be investigated. Traditional methods for fungal identification (culture and microscopy analysis) are laborious, time-consuming and require expertise. To replace cultivation, several techniques have been proposed. This study showed that molecular techniques (PCR-TTGE or Temporal Temperature Gradient Electrophoresis and PCR-DHPLC or Denaturing High Performance Liquid Chromatography) allowed the separation of amplificons corresponding to distinct fungal species that may be encountered in air. Both methods were proved to be appropriate for analysis of complex fungal communities. The detection and the molecular identification techniques were adapted for the evaluation of indoor airborne fungal contamination. The cultivation method and culture-independent techniques were further compared for the analysis of fungal aerosols from different sites

Important research questions are typically studied and analyzed more than once, often by different research teams in different locations. However, in many instances, the results of these multiple small studies are diverse and conflicting, which makes decision-making difficult. The need to arrive at decisions fostered the momentum towards synthesizing the results of these multiple studies. Therefore, meta-analysis, also referred to as the standard or traditional meta-analysis, is a statistical technique for combining the results or findings from multiple independent studies to address a specific research question. The applications of meta-analysis have been extended to many fields of research including medicine, psychology, ecology, education, business and many others. Prior to carrying out a meta-analysis or statistically synthesizing data, a researcher must undertake a systematic review. Systematic review attempts to collate empirical evidence that fits pre-specified eligibility criteria to answer a specific research question. That is to determine which studies will be included or excluded from the analysis. Standard meta-analysis methods are used to obtain the relative efficacy (or safety) of a particular intervention versus a competing intervention in the presence of a direct or head-to-head comparison. Thus only a pair-wise comparison can be made. The outcome of these interventions could be continuous, binary or count data. A number of methodologies related to meta-analysis, assessments of underlying assumptions and strategies for the presentation of results have been proposed by several researchers. A commonly used model for estimating effect sizes in meta-analysis is the fixed-effect model. However, various factors can determine the performance of the model which needs to be considered before using the results for decision making. This project aimed to investigate the performance of hypothesis properties and estimation properties on selecting data points from an underlying contaminated distribution under different scenarios for modeling a continuous outcome. Different levels of contamination, levels of significance, number of studies, number of individual study sample sizes, standard deviations and effect sizes were investigated in our simulation study for a continuous outcome. The results of our simulation study shows that, the fixed-effect meta-analytic model does not perform well in the presence of contamination. As the level of contamination in the treatment group increases, the properties of estimators and hypothesis are greatly influenced. The method performs well as expected in the absence of contamination but performs poorly as we observe 50% contamination in the treatment group regardless of the individual sample size, the number of studies, the standard deviation and the effect size. / Thesis / Master of Science (MSc)

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