ABSTRACT
Clones representing two distinct barley catalase genes, Cat1 and Cat2, were found in a cDNA library prepared from seedling polysomal mRNA. Both clones were sequenced, and their deduced amino acid sequences were found to have high homology with maize and rice catalase genes. Cat1 had a 91% deduced amino acid sequence identity to CAT-1 of maize and 92% to CAT B of rice. Cat2 had 72 and 79% amino acid sequence identities to maize CAT-2 and -3 and 89% to CAT A of rice. Barley, maize or rice isozymes could be divided into two distinct groups by amino acid homologies, with one group homologous to the mitochondria-associated CAT-3 of maize and the other homologous to the maize peroxisomal/glyoxysomal CAT-1. Both barley CATs contained possible peroxisomal targeting signals, but neither had favorable mitochondrial targeting sequences. Cat1 mRNA occurred in whole endosperms (aleurones plus starchy endosperm), in isolated aleurones and in developing seeds, but Cat2 mRNA was virtually absent. Both mRNAs displayed different developmental expression patterns in scutella of germinating seeds. Cat2 mRNA predominated in etiolated seedling shoots and leaf blades. Barley genomic DNA contained two genes for Cat1 and one gene for Cat2. The Cat2 gene was mapped to the long arm of chromosome 4, 2.9 cM in telomeric orientation from the mlo locus conferring resistance to the powdery mildew fungus (Erysiphe graminis f.sp. hordei).
Subject(s)
Catalase/genetics , Hordeum/genetics , Isoenzymes/genetics , Amino Acid Sequence , Cloning, Molecular , DNA, Complementary , Genome, Plant , Hordeum/enzymology , Molecular Sequence Data , RNA, Messenger/genetics , Sequence Homology, Amino AcidSubject(s)
Malaria/epidemiology , Animals , Humans , Plasmodium/isolation & purification , South AfricaABSTRACT
Out of 110 cultures of Plasmodium falciparum obtained from infected patients in Natal 18 were found to be resistant to chloroquine by in vitro tests: 2 cultures showed schizont development in wells containing 24 pmol chloroquine; in 16 schizont development was present in culture wells containing 48 pmol chloroquine. Seventy-two patients with P. falciparum malaria who apparently did not respond to adequate oral chloroquine therapy were investigated. All responded to one or more treatments with pyrimethamine/sulphadoxine (Fansidar; Roche). It would seem that all the patients were infected in areas not controlled by the South African health authorities.
Subject(s)
Chloroquine/therapeutic use , Malaria/drug therapy , Plasmodium falciparum/drug effects , Adolescent , Adult , Animals , Child , Child, Preschool , Chloroquine/pharmacology , Drug Resistance , Humans , South AfricaABSTRACT
Blood samples from 77 patients with Plasmodium falciparum malaria resident in the Natal/Kwazulu area, were tested for chloroquine resistance by an in vitro microtechnique; 6 of these patients were infected by asexual parasites which proved resistant in varying degrees to chloroquine. Resistance, expressed in terms of picomoles chloroquine base per well in which schizont development was completely inhibited, ranged from 16 pmol to greater than 24 pmol. On the evidence it would appear likely that these patients were infected during visits to Mozambique or areas immediately bordering Mozambique.
