The Mbam languages of Cameroon have a unique position in Bantu linguistics. Being in between “narrow” Bantu and “wide” Bantu, they sometimes pattern with the one and sometimes with the other, and... Show moreThe Mbam languages of Cameroon have a unique position in Bantu linguistics. Being in between “narrow” Bantu and “wide” Bantu, they sometimes pattern with the one and sometimes with the other, and as such are a rich motherlode for comparative and historical research. The Mbam languages have another point of interest as well. They have been previously analysed as standard 7 vowel languages (/i,e,ɛ,a,ɔ,o,u/) with Advanced Tongue Root (ATR) harmony. While vowel harmony in African languages has received a lot of attention and study, and the vowel-harmony systems of not a few of the Mbam languages have been studied, most of the previous studies have been on individual languages. This study seeks to analyse and compare the vowel systems of ten Mbam languages as a group: both their vowel inventories and their vowel-harmony systems. Various issues in vowel harmony, such as neutral vowels, directionality in and domains of vowel harmony are discussed. This study also proposes a phonological explanation for the functioning of the complex vowel-harmony systems found in the Mbam languages. Finally this study considers the internal classification of the Mbam languages and their position in the wider linguistic context of the Bantu and Bantoid languages. Show less
Chitin is the second most abundant polymer in nature. In aquatic ecosystems, chitin is mainly present as part of the exoskeleton of arthropods; in soil, chitin is mainly present as component of... Show moreChitin is the second most abundant polymer in nature. In aquatic ecosystems, chitin is mainly present as part of the exoskeleton of arthropods; in soil, chitin is mainly present as component of fungal cell walls. The main enzymes involved in the breakdown of chitin are chitinases. Chitinases are produced by both fungi and bacteria. Chitinases of soil-borne bacteria can decompose chitin of dead fungal hyphae and other resources, but they may also play a role in antagonistic activities against fungi by destroying the chitin in the fungal cell walls. In the research described in this thesis, I tested the hypothesis that bacterial chitinases may perform different functions in different environments and under different circumstances, while the genetic composition and function of bacterial chitinases vary between different habitats. The results obtained in this study have contributed to a better understanding of the ecological functions of bacterial chitinases. New insights in the composition of the bacterial chitinolytic system and the importance of its components were obtained. The potential ecological functions of the bacterial chitinase complex were explored and the role of chitinases in bacteria-fungi interactions, which are vital to the functioning of terrestrial ecosystems, was revealed further. Show less