Escherichia coli dimethylallyl diphosphate:tRNA dimethylallyltransferase (DMAPP-tRNA transferase) catalyzes the first step in the biosynthesis of the hypermodified A37 residue in tRNAs that read codons beginning with uridine. The enzyme, encoded by the miaA gene, was overproduced and purified to apparent homogeneity in three steps by ion-exchange (DE52 and Mono-Q) and size exclusion chromatography. Affinity-tagged DMAPP-tRNA transferase containing a C-terminal tripeptide alpha-tubulin epitope also was overproduced and purified to apparent homogeneity in two steps by ion-exchange and immunoaffinity chromatography. Addition of the C-terminal tripeptide alpha-tubulin epitope to DMAPP-tRNA transferase did not affect the activity of the enzyme. Undermodified tRNA(Phe) used as substrate in the DMAPP-tRNA transferase-catalyzed reaction was isolated and purified from an overexpressing clone in a miaA deficient strain of E. coli. Active recombinant E. coli DMAPP-tRNA transferase is monomeric. The enzyme transferred the dimethylallyl moiety of DMAPP to A37, located adjacent to the anticodon in undermodified tRNA(Phe). The enzyme required Mg2+ for activity and exhibited a broad pH optimum. Michaelis constants for tRNA(Phe) and DMAPP are 96 +/- 11 nM and 3.2 +/- 0.5 microM, respectively, and Vmax = 0.83 +/- 0.02 micromol min-1 mg-1. DMAPP-tRNA transferase bound tRNA(Phe) with a dissociation constant of 5.2 +/- 1.2 nM. In contrast, DMAPP did not bind to the enzyme in the absence of tRNA. However, DMAPP was bound with a dissociation constant of 3.4 +/- 0.6 microM in the presence of a minihelix analogue of the anticodon stem-loop of tRNA(Phe) where the base corresponding to A37 was replaced by inosine. These results suggest an ordered sequential mechanism for substrate binding.

A study of commensals and parasites of 127 Papio cynocephalus captured in semi-desert habitats of the Rift Valley Province, Kenya, revealed the presence of Entamoeba histolytica and eight other intestinal protozoa: Entopolypoides sp. in peripheral blood; two species of lung mites (Pneumonyssus mossambicensis, P. santos-diasi) ; six nematodes (Abbreviata caucasia, Enterobius brevicauda, Oesophagostomum bifurcum, Streptopharagus baylisi, S. pigmentatus, and Trichostrongylus) ; and one cestode (Bertiella studeri).

Entopolypoides macaci occurs in different populations of Papio cynocephalus in Kenya, but not in the same host with Hepatocystis kochi. Parasitemia may be greatly enhanced by splenectomy, but there is little effect on the host in spite of substantial alteration in hemoglobin and RBC counts, and transferability to other primates is erratic. Descriptions are presented for differentiation of E. macaci from H. kochi.

A case is described in which self-mutilation of the genitalia by a female patient was associated with the development of schizophrenia. The psychopathology was dominated by sexual themes and resembled reports of patients with erotomania in the setting of a paranoid or schizophrenic psychosis. The literature on genital mutilation by female and male patients is reviewed briefly. It is suggested that such behaviour in women indicates severely disturbed psychosexual development but lacks diagnostic significance.

Widespread tissue egg deposits and gross lesions were recorded in 15 species of primates subsequent to Schistosoma haematobium (Iran) infections of variable intensity and duration. Considerable extra-intestinal involvement as well as pathology in different parts of the urogenital system were observed. Transitional cell carcinoma of the urinary bladder was recorded for Cebus apella.