The effect of the water-soluble UV-absorbing substance (UVAS) extracted from the marine red alga Porphyra yezoensis Ueda on UV-dependent thymine photodimer production was investigated. The T<>T pyrimidine-pyrimidone 6-4 dimer and the cyclobutane cis-syn T<>T 5-6 dimer produced by UV irradiation with a xenon lamp were analyzed by reverse-phase high-performance liquid chromatography. Although the dimer production was reduced when the irradiation was filtered through a UVAS solution, it decreased more when thymine was mixed with UVAS. Furthermore, UVAS inhibited the degradation of UV-irradiated thymine. The inhibitory effect of UVAS was significantly greater than that of exogenously added adenine or guanine, which forms complementary base pairs with thymine. These data suggest that in addition to its filtering effect against UV radiation, UVAS also protects thymine by a direct molecule-to-molecule energy transfer process. The protective function of UVAS against UV irradiation is advantageous for this alga under strong UV irradiation.

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The fragile histidine triad (FHIT) tumor suppressor gene at 3p14.2 has abnormalities in several types of human cancers. To investigate the potential role of FHIT in cervical cancer, which exhibits frequent loss of heterozygosity of 3p, we have examined primary cervical cancer samples from 28 patients for alterations of the FHIT gene. Abnormal FHIT transcripts were detected using reverse transcription‐polymerase chain reaction (PCR) and subsequently by sequencing. Of 28 primary cervical carcinomas analyzed, 12 tumors (43%) showed abnormal FHIT transcripts, including deletion, insertion and point mutation. Loss of a FHIT transcript was observed in 2 cases (7%). Allelic loss of the FHIT gene was detected in 16 of 27 informative cases (59%). Oncogenic human papillomavirus (HPV) type 16, 18, 33, 35, 58 and 59 were not only present but were expressed in 24 of 28 cases (85%) by consensus PCR‐RFLP (polymerase chain reaction‐restriction fragment length polymorphism) analysis for the HPV E6 and E7 genes. Our data indicate that alteration of the FHIT gene is an important genetic event associated with cervical cancer and oncogenic HPV integration. Int. J. Cancer 76:176–181, 1998.© 1998 Wiley‐Liss, Inc.