Learn More
Most iron in mammalian systems is routed to mitochondria to serve as a substrate for ferrochelatase. Ferrochelatase inserts iron into protoporphyrin IX to form heme which is incorporated into hemoglobin and cytochromes, the dominant hemoproteins in mammals. Tissue-specific regulatory features characterize the heme biosynthetic pathway. In erythroid cells,(More)
The method of shuttle mutagenesis has been extended to Neisseria gonorrhoeae. We have constructed a defective mini-Tn3 derivative that encodes chloramphenicol resistance in both N. gonorrhoeae and Escherichia coli and selected for mutations in the chloramphenicol resistance gene that express higher levels of antibiotic resistance in N. gonorrhoeae. Isogenic(More)
In HeLa cells the majority of transferrin (Tf) receptors are found within the endocytic apparatus, with only 20% of receptors exposed at the cell surface. Receptor distribution is unaltered by the presence or absence of Tf. The mechanism responsible for the cellular distribution of receptors was explored by selectively inactivating receptors within the(More)
BACKGROUND Hemochromatosis occurs in approximately 5 white people per 1000 and is usually due to homozygosity for mutations in the HLA-linked HFE gene. Although screening has been proposed, the proportion of homozygotes with conditions related to hemochromatosis is uncertain. METHODS We studied the prevalence of disease-related conditions among relatives(More)
Mutations that have recently increased in frequency by positive natural selection are an important component of naturally occurring variation that affects fitness. To identify such variants, we developed a method to test for recent selection by estimating the age of an allele from the extent of haplotype sharing at linked sites. Neutral coalescent(More)
Chlamydiae are obligate intracellular parasites which multiply within infected cells in a membrane-bound structure termed an inclusion. Newly internalized bacteria are surrounded by host plasma membrane; however, the source of membrane for the expansion of the inclusion is unknown. To determine if the membrane for the mature inclusion was derived by fusion(More)
We recently identified a set of mammalian cell receptors for Neisseria gonorrhoeae that are glycolipids. These receptors, lactosylceramide [Gal(beta 1-4)Glc(beta 1-1)Cer], gangliotriosylceramide [GalNAc( beta 1-4)Gal(beta 1-4)Glc(beta 1-1)Cer], and gangliotetraosylceramide [Gal(beta 1-3)GalNAc(beta 1-4)Gal(beta 1-4)Glc(beta 1-1)Cer], were shown to be(More)
We have employed a modification of the horseradish peroxidase (HRP)-diaminobenzidine density shift technique of Courtoy et al. (J. Cell Biol., 1984, 98:870-876) to examine the biochemical properties of the endosome. This organelle is involved in receptor recycling and the sorting of internalized receptor ligand complexes. Transferrin covalently bound to HRP(More)
Multiplex polymerase chain reaction amplification and genotyping by fluorescent probe melting temperature (Tm) was used to simultaneously detect multiple variants in the hereditary hemochromatosis gene. Homogenous real-time analysis by fluorescent melting curves has previously been used to genotype single base mismatches; however, the current method(More)
AIMS/HYPOTHESIS The prevalence and mechanisms of diabetes in hereditary haemochromatosis are not known. We therefore measured glucose tolerance, insulin secretory capacity and insulin sensitivity in adults with haemochromatosis. SUBJECTS AND METHODS Subjects recruited from referrals to a haemochromatosis clinic underwent OGTT and frequently sampled IVGTT.(More)