| Summary: | 博士 === 國立陽明大學 === 公共衛生研究所 === 106 === Public Health is a multidisciplinary field aiming to promote populations health trough organized community efforts. Through such efforts, many infectious diseases that were huge burdens are nowadays under control. The Primary Amoebic Meningoencephalitis (PAM) is, for the most of communities, an unknown thus neglected infectious disease caused by the brain eating amoeba: Naegleria fowleri. Like the disease it causes, this single cell free-living amoeba is not well known; especially in ecological and biological fields.
Herein, we (1) investigated the nutrient-related and temperature-related effects on N. fowleri. The growth profiles of N. fowleri using liquid media with different ingredient compositions at different range of temperature were established. Secondarily, we (2) investigated the presence of essential non-neuronal cholinergic system genes and the ability of N. fowleri to produce acetylcholine. Subsequently, we evaluated the role of acetylcholine in N. fowleri trophozoites migration, proliferation and morphology.
From the first part of this thesis, we demonstrated that supplementation with peptone promotes the parasites growth at 25, 37 and 43°C. Besides, yeast extract had an inhibitory effect and was able to swamp the growth promoting effect of peptone.
In the second part of the thesis, we found that N. fowleri LDL possesses and expressed mAChR, AChE and CLT genes. However, no significant nucleotides sequence of ChAT was discovered. Furthermore, we demonstrated that the parasite was producing ACh with extracellular accumulation. Thus, we noted that ACh was (a) involved in the parasite migration, (b) keeping the trophozoites alive in non-growth promoting medium, and (c) involved in the transformation of trophozoites in cysts.
Overall, we believe that populations should avoid diving in waters especially if they contain organic debris like peptone promoting the parasite growth. Moreover, we suggest that a better prevention or treatment of PAM requires the development of anticholinergic drugs.
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