Prevalence of human papillomavirus in oral gargles and tonsillar washings.

OBJECTIVES: Human papillomavirus (HPV) infection drives carcinogenesis in the oropharynx. No standard sampling or HPV detection methods for evaluating oropharyngeal HPV infection exist. The prevalence of oral HPV infection in Japan is unknown. MATERIALS AND METHODS: We examined 435 healthy Japanese individuals to address whether adding tonsillar washing to oral gargling would improve HPV detection. We compared HPV assessment using GENOSEARCH HPV31 versus nested PCR and direct sequencing. Associations between HPV infection and demographic and behavioral characteristics were examined. RESULTS: Most participants who were HPV-positive based on oral gargles were also HPV-positive based on tonsillar washings: 11 (64.7%) of 17 on nested PCR and 12 (70.6%) of 17 on GENOSEARCH HPV31. Although HPV infection was more prevalent in oral gargles followed by tonsillar washings than in oral gargles alone, the difference was not statistically significant (nested PCR, 4.8% vs. 3.9%, P = 0.46; GENOSEARCH HPV31, 5.3% vs. 3.9%, P = 0.33). The overall agreement between nested PCR and GENOSEARCH HPV31 was 98.6%, with 76.0% positive agreement. The overall prevalence of oral HPV infection in Japan was 5.7% (95% confidence interval, 3.9-8.3%). Men had a significantly higher prevalence of oral HPV infection than women (8.3% vs. 2.6%, P = 0.02). Infection increased with number of lifetime sexual partners (P < 0.001 for trend). CONCLUSION: The oropharynx is probably the major source of HPV-infected cells in oral gargles. Oral gargling could be a standard sampling method for evaluating oropharyngeal HPV infection. GENOSEARCH HPV31 could be an option for oral HPV detection.

Genome sequence of an industrial microorganism Streptomyces avermitilis: deducing the ability of producing secondary metabolites.

Streptomyces avermitilis is a soil bacterium that carries out not only a complex morphological differentiation but also the production of secondary metabolites, one of which, avermectin, is commercially important in human and veterinary medicine. The major interest in this genus Streptomyces is the diversity of its production of secondary metabolites as an industrial microorganism. A major factor in its prominence as a producer of the variety of secondary metabolites is its possession of several metabolic pathways for biosynthesis. Here we report sequence analysis of S. avermitilis, covering 99% of its genome. At least 8.7 million base pairs exist in the linear chromosome; this is the largest bacterial genome sequence, and it provides insights into the intrinsic diversity of the production of the secondary metabolites of Streptomyces. Twenty-five kinds of secondary metabolite gene clusters were found in the genome of S. avermitilis. Four of them are concerned with the biosyntheses of melanin pigments, in which two clusters encode tyrosinase and its cofactor, another two encode an ochronotic pigment derived from homogentiginic acid, and another polyketide-derived melanin. The gene clusters for carotenoid and siderophore biosyntheses are composed of seven and five genes, respectively. There are eight kinds of gene clusters for type-I polyketide compound biosyntheses, and two clusters are involved in the biosyntheses of type-II polyketide-derived compounds. Furthermore, a polyketide synthase that resembles phloroglucinol synthase was detected. Eight clusters are involved in the biosyntheses of peptide compounds that are synthesized by nonribosomal peptide synthetases. These secondary metabolite clusters are widely located in the genome but half of them are near both ends of the genome. The total length of these clusters occupies about 6.4% of the genome.

Overexpression of phospholipid hydroperoxide glutathione peroxidase suppressed cell death due to oxidative damage in rat basophile leukemia cells (RBL-2H3).

The role of phospholipid hydroperoxide glutathione peroxidase (PHGPx) in the cellular defense against oxidative stress was investigated in a novel cell model. We isolated stable transfectants of RBL-2H3 cells that overexpressed PHGPx. The activity of PHGPx in RBL2H3 cells that had been transfected with the 761bp cDNA for rat PHGPx (RPHGPx2) that we had cloned previously was 3.8 times higher than that in parent cells and in cells that had been mock-transfected with the vector without a cDNA insert. Cells that overexpressed PHGPx were three times more resistant than parent cells and mock-transfected cells to the cytotoxic effects of an radical initiator (AAPH) that induced the oxidative stress. This resistance to damage by AAPH of cells that overexpressed PHGPx was not observed after pretreatment with buthionine sulfoximine (BSO), an inhibitor of the synthesis of glutathione. Overexpression of PHGPx could suppress the peroxidation of membrane lipids and, in particular, the production of phosphatidylcholine hydroperoxide by AAPH in RBL2H3 cells. PHGPx was also able to prevent cell death in response to extracellular attack by a lipid peroxide. This is the first report to indicate directly that PHGPx can scavenge phosphatidylcholine hydroperoxide, which induces oxidative damage at the cellular level.

Molecular cloning and functional expression of a cDNA for rat phospholipid hydroperoxide glutathione peroxidase: 3'-untranslated region of the gene is necessary for functional expression.

A full-length cDNA clone for phospholipid hydroperoxide glutathione peroxidase (PHGPx) was isolated from a rat brain. The cDNA was 0.761 kb in length and encoded 170 amino acids, which included a TGA-encoded selenocysteine at residue 46. The protein has a calculated molecular mass of 19,473 Da. We succeeded in the transient functional expression of a full-length cDNA for PHGPx, which includes the 3'-UTR, in COS-7 cells at the first attempt. Deletion of the 3'-UTR prevented the expression of the PHGPx activity and the incorporation of [75Se]selenious acid into the monomeric 19.7 kDa PHGPx protein. Thus, the 3'-UTR of the cDNA for PHGPx was required for the functional expression of PHGPx. Northern blot analysis demonstrated that the mRNA for PHGPx was widely expressed in normal rat tissues, especially in the testis. The mRNA levels of PHGPx in the cultured cells such as hepatomas, neuronal cells, nephroblastoma, and mammary myo-epithelial cells were higher than those of the tissues. The ratio of PHGPx to cytosolic glutathione peroxidase (cGPx) was significantly high in the testis and relatively high in the cultured cells. The mRNA levels of PHGPx in tissues were lower than those of cGPx.