Genetic controls on starch amylose content in wheat and rice grains

Starch accumulates in plants as granules in chloroplasts of source organs such as leaves (transitory starch) or in amyloplasts of sink organs such as seeds, tubers and roots (storage starch). Starch is composed of two types of glucose polymers: the essentially linear polymer amylose and highly branched amylopectin. The amylose content of wheat and rice seeds is an important quality trait, affecting the nutritional and sensory quality of two of the world’s most important crops. In this review, we focus on the relationship between amylose biosynthesis and the structure, physical behaviour and functionality of wheat and rice grains. We briefly describe the structure and composition of starch and then in more detail describe what is known about the mechanism of amylose synthesis and how the amount of amylose in starch might be controlled. This more specifically includes analysis of GBSS alleles, the relationship between waxy allelic forms and amylose, and related quantitative trait loci. Finally, different methods for increasing or lowering amylose content are evaluated.     

Further Studies in the Chemotherapy of Plasmodium hexamerium Infections in Ducks

Five standard antimalarial drugs have been tested, in the present study, against trophozoite-induced Plasmodium hexamerium infections in ducks; namely, chloroquine, proguanil (paludrine), pyrimethamine (daraprim), pentaquine and isopentaquine. (Four others were used previously.) Two doses daily were given for a treatment period of 7 days. The effectiveness of treatment was measured in terms of its ability to suppress parasitemia and to completely prevent relapse ( i.e. to achieve sterilization). Of the five drugs, the two pentaquines were about equally effective. They rapidly cleared the blood of parasites, and completely aborted the infection in nearly all cases. The other three drugs failed to sterilize any of the cases treated, and were not even effective as suppressants.
The pentaquines, however, proved quite toxic to the host and, even in the dosages used, retarded the normal rate of weight gain. Pyrimethamine had a similar effect, and in addition interfered with normal feathering. Neither of these effects, whether due to pentaquines or pyrimethamine, was recovered from after treatment stopped.