A systematic revision of the genus Laelaps s. str. (Acari: Mesostigmata) of the Ethiopian region

This paper presents the results of a systematic study of mites of the genus Laelaps s. str. collected from small mammals of the Ethiopian region. Specimens taken from approximately 100,000 small mammals were examined from a wide variety of habitats and localities. The Ethiopian fauna of Laelaps mites includes 31 species. 4 of which are described as new: L. parasimillimus, L. myomys, L. malacomys, and L. acomys. A numerical taxonomic analysis was made, the results of which were used in the preparation of a proposed classification of the African species of Laelaps. A key for identification of females is given, and females and males (where known) of all species are illustrated. Diagnostic characters are given for the female and male of each species. Collection data and, where pertinent, discussions of morphological characters and variability are provided. Also included are discussions of host-parasite associations.     

Fatal infantile cardioencephalomyopathy with COX deficiency and mutations in SCO2, a COX assembly gene.

Mammalian cytochrome c oxidase (COX) catalyses the transfer of reducing equivalents from cytochrome c to molecular oxygen and pumps protons across the inner mitochondrial membrane. Mitochondrial DNA (mtDNA) encodes three COX subunits (I-III) and nuclear DNA (nDNA) encodes ten. In addition, ancillary proteins are required for the correct assembly and function of COX (refs 2, 3, 4, 5, 6). Although pathogenic mutations in mtDNA-encoded COX subunits have been described, no mutations in the nDNA-encoded subunits have been uncovered in any mendelian-inherited COX deficiency disorder. In yeast, two related COX assembly genes, SCO1 and SCO2 (for synthesis of cytochrome c oxidase), enable subunits I and II to be incorporated into the holoprotein. Here we have identified mutations in the human homologue, SCO2, in three unrelated infants with a newly recognized fatal cardioencephalomyopathy and COX deficiency. Immunohistochemical studies implied that the enzymatic deficiency, which was most severe in cardiac and skeletal muscle, was due to the loss of mtDNA-encoded COX subunits. The clinical phenotype caused by mutations in human SCO2 differs from that caused by mutations in SURF1, the only other known COX assembly gene associated with a human disease, Leigh syndrome.