This thesis is concerned with a study of the Chironomidae occuring in a saline lake series in central British Columbia. It describes the ecological distribution of species, their abundance, phenology and interaction, with particular attention being paid to Chironomus tentans. Emphasis is placed on the species of Chironomus that coexist in these lakes and a further analysis is made of the chromosome inversion frequencies in C. tentans. Of the thirty-four species represented by identifiable adults in the study, eleven species have not been previously reported in British Columbia, five are new records for Canada and seven species are new to science. The chironomid fauna of the lake series is divided into dominant associations whose existence seems to depend on salinity and productivity levels. A Cricotopus albanus -Procladius bellus - Ablabesmyia peleensis association prevails in the lowest salinities (40 to 80 μmho/cm conductivity) while in conductivities between 400 and 2800 μmho/cm a Glyptotendipes barbipes - Einfeldia pagana association dominates. In the most saline lakes (conductivity 4100 to 12000 μmho/cm) a Calopsectra gracilenta - Cryptotendipes ariel association is characteristic. Analysis of physical and chemical factors influencing the life cycle of C. tentans indicates that conditions associated with high levels of organic carbon promote large numbers of larvae and greater emergence success. The results suggest that competition between C. tentans and other Chironomus species is reduced through spatial separation due to different preferences for salinity or related factors. Furthermore, temporal separation among these and other abundant species such as G. barbipes and E. pagana occurs as a result of staggered generation times. The inversion frequency in chromosome 1 of C. tentans is negatively correlated with organic carbon levels and positively correlated with dissolved oxygen and the abundance of Glyptotendipes barbipes. Since the inversion frequency is lowest in habitats where competing species are few and where C. tentans is most successful, it is suggested that the inversion governs a mechanism reducing competition. A major contribution of this work is the revision of the distribution of many of the chironomid species under consideration. In the past, little research has been done on populations of chironomids in a saline lake series. The present study, in attempting to fill this gap in entomological research, shows that a species' life history and population structure can vary radically in closely associated lakes of differing chemical and biological constitution. / Science, Faculty of / Zoology, Department of / Graduate

Ecological adaptation has occupied a central position in evolutionary theory for over 100 years; however, surprisingly little is known in detail of its significance. This study was undertaken to determine if chromosomal inversions of larvae of Chironomus tentans have any selective significance in nature and if they do, to define the relationship between genetic adaptation, as reflected by the frequencies of the inversions, and the ecological conditions to which the species mast be adapted. The procedure used was (1) to define the habitats potentially available to C. tentans, (2) to define the ecological conditions to which C. tentans is adapted, and (3) to define the relationship between inversion frequency and those ecological conditions to which C. tentans has been found to be adapted. The environmental properties of 32 saline lakes located in south-central British Columbia were studied. The lakes differed in total chemical concentration, ranging from very fresh to four or five times the concentration of sea water. Measurements of temperature, conductivity of the water, total dissolved solids, and pH, and of concentrations of dissolved oxygen, sodium, potassium, calcium, magnesium, carbonate, bicarbonate, chloride, and sulfate were made during different seasons at different depths in most of the lakes. Surface water samples were analyzed by a semi-quantitative technique for 28 trace elements. Selected samples of bottom muds were analyzed for substrate composition and percentage organic carbon content. Analysis of the environmental properties indicated that the chemical concentrations of the lakes varied both seasonally and with depth. Sodium, magnesium, carbonate-bicarbonate, and sulfate were the ions present at the greatest concentrations. The occurrence and abundance of larvae of C. tentans were determined with respect to the environmental properties of the lakes. C. tentans was found to occur in only 17 of the 32 lakes studied and each of the 17 lakes had conductivities within the range of from 500 to 4,500 micromhos. Further, C. tentans occurred only in the upper two meters of these lakes and was most abundant at the shallower depths of its occurrence. Both occurrence and abundance of C. tentans were correlated primarily with chemical concentration, although other environmental factors also were found to be important. Analysis of the frequencies of certain inversions present in chromosome 1 indicated that, populations present in different environments may have significantly different inversion frequencies, that the frequencies did not vary seasonally and were extremely stable over time periods as long as eight years, and that the inversion frequencies of sub-divisions of populations living within lakes do not vary significantly, Although C. tentans was found to show considerable ecological adaptation to lake water chemistry, no obvious relationship between the frequencies of the inversions of chromosome 1 and lake water chemistry could be detected. The studies of correlation of inversion frequencies with environmental properties and the results of a field experiment indicate that C. tentans is genetically adapted primarily to its co-occurrence with other chironomids. A lesser correlation with pH was also detected. Consequently, although genetic adaptation to environmental factors was found, that genetic adaptation was not to the major differences which occurred between the lakes. The unique and major contributions of this study are the demonstration that the inversions of chromosome 1 have selective significance in nature and that not all ecological adaptation is accompanied by parallel genetic adaptation (as reflected by inversion frequency). The clear implication is that although ecological adaptations may have evolutionary significance, not all ecological adaptations do. / Science, Faculty of / Zoology, Department of / Graduate

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 98-104). Also available via the Internet.

Thesis (M.S.)--Northern Michigan University, 2007. / Bibliography: leaves 31-34.

Diss. phil.-naturwiss. Bern, 1983.

Thesis (doctoral)--Lund University, 1997. / Added t.p. with thesis statement inserted.

Thesis (doctoral)--Lund University, 1997. / Added t.p. with thesis statement inserted.

No description available.

Wong Kwong Fai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 97-104). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract --- p.ii / List of Figures --- p.x / List of Tables --- p.xi / List of Abbreviations --- p.xii / Chapter Chapter One --- Introduction --- p.1 / General background and objective of this study --- p.1 / Chapter Part One --- Early studies on ferrochelatase from chironomidae larvae / Chapter 1.1 --- Purification of ferrochelatases from different organisms --- p.5 / Chapter 1.2 --- Purification of ferrochelatase from chironomidae larvae --- p.5 / Chapter 1.3 --- Molecular cloning of ferrochelatase from chironomidae larvae --- p.6 / Chapter 1.4 --- Expression of recombinant chironomidae ferrochelatase --- p.8 / Chapter Part Two --- Study on the iron-sulfur cluster of chironomidae ferrochelatase / Chapter 2.1 --- Presence of iron-sulfur cluster at chironomidae ferrochelatase --- p.13 / Chapter 2.2 --- Possible roles of iron-sulfur cluster at ferrochelatase --- p.13 / Chapter 2.3 --- Mutagenesis study of iron-sulfur cluster at chironomidae ferrochelatase --- p.14 / Chapter Part Three --- Study on the catalytic mechanism of ferrochelatase / Chapter 3.1 --- Binding and distortion of porphyrin --- p.17 / Chapter 3.2 --- Binding of ferrous iron to ferrochelatase --- p.18 / Chapter Part Four --- Study on the effect of metal ions on ferrochelatase / Chapter 4.1 --- Previous studies on the effects of metal ions on different ferrochelatases --- p.24 / Chapter 4.2 --- Effects of metal ions on chironomidae ferrochelatase --- p.24 / Chapter Chapter Two --- Methods and Materials --- p.28 / General procedure --- p.28 / Chapter Part One --- Cloning of chironomidae ferrochelatase coding fragment / Chapter 1.1 --- Amplification of chironomidae ferrochelatase coding cDNA --- p.29 / Chapter 1.2 --- Construction of the expression vector (pETBlue-FECH) --- p.30 / Chapter Part Two --- Mutagenesis / Chapter 2.1 --- Choices of residue replacements --- p.31 / Chapter 2.2 --- Constructions of mutant plasmids --- p.31 / Chapter 2.3 --- Screenings of mutant plasmids --- p.32 / Chapter Part Three --- Construction of chironomidae-human hybrid plasmid / Chapter 3.1 --- Human RNA isolation --- p.33 / Chapter 3.2 --- Human cDNA synthesis --- p.33 / Chapter 3.3 --- Construction of human ferrochelatase expression plasmid (pETBlue-HFECH) --- p.34 / Chapter 3.4 --- Construction of chironomidae-human hybrid plasmid (pETBlue-HYB-FECH) --- p.34 / Chapter 3.4.1 --- First round PCR --- p.34 / Chapter 3.4.2 --- Second round PCR --- p.34 / Chapter 3.4.3 --- Overlapping PCR --- p.35 / Chapter 3.4.4 --- Cloning of HYB-FECH --- p.35 / Chapter Part Four --- Protein expression and purification / Chapter 4.1 --- Protein expression in bacterial expression system --- p.36 / Chapter 4.2 --- Cell harvest and ammonium sulfate fractionation --- p.36 / Chapter 4.3 --- Protein purifications by Blue Sepharose CL-6B chromatography --- p.37 / Chapter 4.4 --- Precipitation of protein samples for SDS-PAGE analysis --- p.37 / Chapter 4.5 --- Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) --- p.38 / Chapter 4.6 --- Fast protein liquid chromatography (FPLC) --- p.38 / Chapter Part Five --- Functional study of expressed ferrochelatase / Chapter 5.1 --- Kinetic measurements --- p.40 / Chapter 5.2 --- Metal titration and fluorescence spectroscopy --- p.40 / Chapter Part Six --- Homology modeling of chironomidae ferrochelatase --- p.42 / Chapter Part Seven --- Other routine laboratory methods / Chapter 7.1 --- Determination of nucleic acid --- p.44 / Chapter 7.2 --- Determination of protein --- p.44 / Chapter 7.3 --- Agarose gel electrophoresis of DNA --- p.44 / Chapter 7.4 --- Agarose gel electrophoresis of RNA --- p.45 / Chapter 7.5 --- Nucleic acid purification --- p.45 / Chapter 7.6 --- Preparation of chemically competent bacterial cells --- p.46 / Chapter 7.7 --- Heat shock transformation of competent bacterial cells --- p.46 / Chapter 7.8 --- Colony PCR --- p.47 / Chapter 7.9 --- Plasmid rescue by alkaline lysis --- p.48 / Chapter 7.10 --- Washing of Blue Sepharose CL-6B column --- p.48 / Chapter Chapter Three --- Results --- p.49 / Chapter Part One --- Protein expression and purification --- p.49 / Chapter Part Two --- Kinetic study of chironomidae ferrochelatase --- p.53 / Chapter Part Three --- Mutagenesis study of iron-sulfur cluster --- p.56 / Chapter Part Four --- Mutagenesis study of metalation by ferrous iron / Chapter 4.1 --- Mutagenesis study at His234 --- p.58 / Chapter 4.2 --- "Mutagenesis study at Glu310, Glu313 and Glu317" --- p.58 / Chapter Part Five --- Copper activation of chironomidae ferrochelatase / Chapter 5.1 --- Kinetic analysis of copper activation --- p.62 / Chapter 5.2 --- Copper activation on chironomidae-human hybrid (HYB-FECH) --- p.63 / Chapter 5.3 --- Mutagenesis study on copper activation --- p.63 / Chapter Part Six --- Homology modeling of chironomidae ferrochelatase --- p.70 / Chapter Chapter Four --- Discussion --- p.72 / Chapter Part One --- Protein expression and purification --- p.72 / Chapter Part Two --- Mutant constructions by QuikChange´ёØ approach --- p.73 / Chapter Part Three --- Kinetic study of expressed chironomidae ferrochelatase --- p.74 / Chapter Part Four --- Mutagenesis study of iron sulfur cluster / Chapter 4.1 --- Location of cysteine residues forming the iron-sulfur cluster --- p.77 / Chapter Part Five --- Mutagenesis study of metalation by ferrous iron / Chapter 5.1 --- Role of His234 --- p.79 / Chapter 5.2 --- Catalytic roles of Glu310，Glu313 and Glu317 --- p.80 / Chapter 5.3 --- "Substrate binding on Glu310, Glu313 and Glu317" --- p.83 / Chapter 5.4 --- Partial picture of metalation and future work on active site residues --- p.84 / Chapter 5.5 --- Future works on the active site residues --- p.84 / Chapter Part Six --- Copper activation of chironomidae ferrochelatase / Chapter 6.1 --- Chironomidae ferrochelatase interaction with copper (II) ion --- p.88 / Chapter 6.2 --- Putative copper-binding sites on chironomidae ferrochelatase --- p.89 / Chapter 6.3 --- The hypothesized model of copper activation --- p.90 / Chapter 6.4 --- Direct copper involvement in catalysis --- p.91 / Chapter Chapter Five --- Summary --- p.94 / Chapter Chapter Six --- References --- p.97

Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 5 uppsatser.