https://www.um.edu.mt/library/oar/handle/123456789/2283 2026-04-13T11:17:24Z https://www.um.edu.mt/library/oar/handle/123456789/10312 Title: The effect of survival motor neuron deficiency on motor function in Drosophila Abstract: Spinal muscular atrophy (SMA) is a neurodegenerative disease that results from mutations present within the survival of motor neuron (SMN) gene. SMA is caused by a quantitative reduction (not total absence) of SMN protein. In humans, the SMN complex is an essential multi-protein molecule composed of an integral SMN protein, Gemins 2-8 and Unrip, which is crucial for small nuclear ribonucleoproteins (snRNP) assembly. In the present study, the SMN protein was studied using the model organism Drosophila melanogaster. The fly has been successfully used in the study of many neurodegenerative diseases, particularly due to human gene homologues and conserved neuromuscular physiology. With the use of three different SMN mutations, SMA was modelled by creating fly genotypes which were assessed for neuromuscular degeneration. The fly genotypes that were generated were subjected to a battery of behavioural tests which included locomotor and flight ability assays. Neuromuscular dysfunction presenting as flight defects were seen in mutant flies, as well as reduced lifespan. We also tested the role of SMN on adult viability by selectively decreasing expression levels of SMN in different tissues. Our results showed that SMN deprivation within glial cells results in total fly lethality. These findings show that different SMN mutations cause significant effects on motor function and that SMN has both a tissue-specific and ubiquitous role in Drosophila, beginning at even the primal stages of development. Together, these characteristics influence the formation of the SMN complex, its function and allow us to further understand the molecular pathogenesis of SMA. Description: B.SC.(HONS)BIOMED.SCI. 2014-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/10309 Title: Application of hyperspectral imaging as a tool to assess microbial responses Abstract: In the last few years, advances in innovative science have provided new technologies to enhance food safety and quality. Sensitive and rapid microbial detection methods are a key solution for the prevention of foodborne diseases. This has a major ripple effect on health and safety world-wide. Standard microbial detection methods such as direct plate counting, immunological methods and methods based on polymerase chain reactions have the main limitations of being time-consuming and labour-intensive. Research in novel and progressive techniques such as hyperspectral imaging enables the development of new microbial detection methods that can overcome the limitations of conventional methods. This study deals with the simultaneous use of hyperspectral imaging and the conventional plate counting method to assess the growth patterns of Escherichia coli NCTC 12900 (sub-type of E. coli 0157) stored at different environmental temperatures. The growth curves and generation times obtained by analysing microbial data shows that E. coli NCTC 12900 grows better at 400C rather than the characteristic optimal temperature of 370C associated with most E. coli 0157 strains. Hyperspectral images of test and control Agar stimulant systems were analysed using Matlab software to obtain separate normalized histograms. The Bhattacharyya distance analysis was then used to obtain plots which show the pattern of microbial growth with time in relation to light absorbance and reflectance detected by the hyperspectral camera. Due to various limitations and confounding variables in the method used in this study to acquire and assess hyperspectral images, correlation between data obtained in the traditional plate counting method and hyperspectral imaging was not possible. Consequently, further research needs to be carried out to better understand the on-line applicability of hyperspectral imaging in quality control measures related to food quality and safety. Description: B.SC.(HONS)BIOMED.SCI. 2014-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/10306 Title: The determination of baseline fungal spore counts in air and water at Mater Dei hospital Abstract: Fungal presence represents a constant threat in hospitals, especially for immunocompromised patients. Atmospheric fungi may cause several nosocomial infections, among which Aspergillus spp. is the most common etiological agent. Highly efficient air filters, restrictive access conditions and reverse osmosis systems do not completely eliminate atmospheric fungi; hence lays the importance to implement routine air and water sampling with respect to mycological investigations in hospital environments. This study was aimed to determine the baseline airborne and waterborne fungal counts at Mater Dei Hospital in a rapid, cost-effective manner, using the SAS Super 180 air sampler to extract air onto Sabouraud Dextrose Agar with Chloramphenicol (SDC) culture media. Water samples collected were filtered through nitrocellulose membrane filters which were then applied to SDC media. Colonies cultured were counted and identified, and the air and water fungal load was then calculated. As a result, the effectiveness of the preventive systems currently set in place was assessed. Areas equipped with different air filtration systems and varied restrictive conditions were tested during summer and winter seasons, on a period of 5 months. The outer hospital surroundings were used as a control for air sampling. High air filtration efficiency corresponded to a low air fungal load, while fungal presence in water was seen to drastically decrease with the installation of an additional water filter inside the water tap. The ultra clean operating theatres equipped with the most efficient air filters and highly restrictive access yielded a zero fungal spore count. Atmospheric fungi were seen to have a seasonal variation, with higher counts found during summer months. Results were consistent with those found in similar studies, where it was shown that the efficiency of air filtration systems and restrictive access conditions may prevent a high atmospheric fungal load. In future studies, fungal counts may be used as baseline values. Moreover, given that a zero presence of fungi is attainable at present; these findings may help in the design of the new Oncology centre in Malta. Description: B.SC.(HONS)BIOMED.SCI. 2014-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/10305 Title: Investigating the current blood culture system for possible improvements in isolation of fungal pathogens Abstract: Invasive fungal infections are the cause of morbidity and mortality in developed countries. Unfortunately blood culture systems possess several limitations in the isolation of fungi. The lack of ability to culture Aspergillus species from blood in invasive aspergillosis is probably the most important limitation in the diagnosis of fungal infections. The aim of this project was to evaluate the blood culture system (BacT/Alert) for possible improvements in the isolation of fungi. In the first part of this project, the growth of four Aspergillus species was evaluated in the Standard Aerobic and FAN Aerobic blood culture media. Terminal subcultures were then prepared using a 'novel' subculture technique. In the second part of the project false negatives were tested by preparing terminal subcultures from automated negative blood cultures, which contained the blood of neutropenic and immunocompromised patients. All four species were detected visually in both bottles between 24 and 48 hours, at the highest conidial concentration. Growth was less successful in the bottles inoculated with the hyphal suspensions due to serious limitations in the technique used for their preparation. The novel subculture technique was also successful in the recovery of Aspergillus on solid media, even at the lowest inocula concentrations. After performing terminal subcultures, Candida tropicalis was recovered from one automated negative bottle, thus identifying a false negative. The results obtained were compared with similar studies which utilised the BACTEC blood culture system. The latter produced better results. This study has shown that blood culture media support the growth of Aspergillus. This is concordant with similar studies performed on other blood culture systems. The challenge is therefore finding the cause for the lack of positive blood cultures in patients with invasive aspergillosis. This study has also shown the importance of terminal subcultures in cases of suspected Candidaemia. Description: B.SC.(HONS)BIOMED.SCI. 2014-01-01T00:00:00Z