The bifunctional dihydrofolate reductase-thymidylate synthase (DHFR-TS) gene from the monogenetic kinetoplastid protozoan, Crithidia fasciculata, was isolated and characterized. The gene is located on a single chromosome of approximately one megabase, and shows significant sequence similarity to other eukaryotic and prokaryotic DHFR and TS genes. There is a single low-abundance polyadenylated D...

In this study we analyze and compare the trends in codon usage in five representative species of kinetoplastid protozoans (Crithidia fasciculata, Leishmania donovani, L. major, Trypanosoma cruzi and T. brucei), with the purpose of investigating the processes underlying these trends. A principal component analysis shows that the G+C content at the third codon position represents the main source ...

Introduction The flavoprotein disulphide oxidoreductases constitute a growing family of homologous dimeric enzymes, with an important and diverse range of functions in vivo. Among its members are dihydrolipoyl dehydrogenase, glutathione reductase, mercuric reductase, thioredoxin reductase, trypanothione reductase and a related enzyme, NADPH peroxidase (for recent reviews of their structures and...

Scattered small stands of Nothofagus truncata occur in the upper Taramakau catchment, Arthur's Pass National Park, beyond the previously assumed range of the species in north Westland. Restricted to older soils on stable north to north-west slopes, the N. truncata stands are surrounded by N. fusca dominated forest and their upper altitudinal limits at 370-500 m border N. fusca-N. menziesii or N...

The Palaearctic Bombus ruderatus (in 1982/1983) and Bombus terrestris (1998) have both been introduced into South America (Chile) for pollination purposes. We here report on the results of sampling campaigns in 2004, and 2010-2012 showing that both species have established and massively expanded their range. Bombus terrestris, in particular, has spread by some 200 km year(-1) and had reached th...

1. The motile response of the flagellum of Crithidia oncopelti to changes in the temperature, pressure and viscosity of the environment were studied. 2. The dependence of beat frequency on temperature and pressure can be interpreted in terms of the theory of reaction rates by making the assumption that the frequency is proportional to the rate constant of a chemical reaction within the flagellu...

Honey bees and, more recently, bumblebees have been domesticated and are now managed commercially primarily for crop pollination, mixing with wild pollinators during foraging on shared flower resources. There is mounting evidence that managed honey bees or commercially produced bumblebees may affect the health of wild pollinators such as bumblebees by increasing competition for resources and th...