A series 11 gamma-ray-induced mutants at the dihydrofolate reductase (dhfr) locus in Chinese hamster ovary cells has been examined for the types of DNA sequence change brought about by this form of ionizing radiation. All 11 mutants were found to have suffered major structural changes affecting the dhfr gene. In eight of the mutants, all or part of the dhfr gene has been deleted. The extent of these deletions was examined in seven of these mutants and, for comparison, in two deletion mutants that were induced by UV irradiation. For this purpose, probes from an overlapping set of cosmids that span 210 kb of DNA in this region were used. Three of seven gamma-ray-induced mutants and one UV-induced mutant were shown to have deleted the entire 210-kb region. In the remaining mutants, endpoints ranging from within the dhfr gene to 100 kb downstream were observed. No upstream endpoints were detected, so that an upper limit on the size of these large deletions could not be assigned. Three of the 11 gamma-ray-induced mutants contained an interruption in the dhfr gene without any detectable loss of sequence. Restriction analysis of these interrupted mutants showed that at least 8-14 kb of "foreign" DNA sequence became joined to the gene at the point of disruption. Cytogenetic analysis of these mutants showed that in two cases an inversion of the banding pattern on chromosome Z-2 had taken place. The inverted dhfr mutants contain very low amounts of dhfr RNA sequences, and the 5' end of an inversion mutant gene exhibits the same pattern of DNA methylation and DNase I-hypersensitivity as the wild-type gene. Our results suggest that ionizing radiation causes primarily, if not exclusively, large deletions and inversions in mammalian cells.

Three extracts, namely hot-water fraction (HWF), water-soluble fraction (WSF), and ethanol-soluble fraction (ESF), were prepared from fresh bee bread imported from Lithuania. The protein and total phenolic contents of these samples were very high. Among them, WSF at 100% concentration showed the highest antioxidative ability and scavenging ability. On the other hand, ESF at 10% concentration possessed the highest ability against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radicals. Bee bread will apply more and more as health food and medicine due to its functional properties such as antioxidative ability and scavenging activities of reactive oxygen species.

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Various antimicrobial constituents of camu-camu fruit were isolated. Acylphloroglucinol (compound 1) and rhodomyrtone (compound 2) were isolated from the peel of camu-camu (Myrciaria dubia) fruit, while two other acylphloroglucinols (compounds 3 and 4) were obtained from camu-camu seeds. The structures of the isolated compounds were characterized by spectrophotometric methods. Compounds 1 and 4 were confirmed to be new acylphloroglucinols with different substituents at the C7 or C9 position of 2, and were named myrciarone A and B, respectively. Compound 3 was determined to be isomyrtucommulone B. This is the first report of the isolation of 3 from a natural resource. The antimicrobial activities of compounds 1, 3, and 4 were similar to those of 2, and the minimum inhibitory concentrations were either similar to or lower than that of kanamycin. These results suggest that the peel and seeds of camu-camu fruit could be utilized for therapeutic applications.

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Garlic is used as a spice in cooking due to its unique aroma. The unique aroma of garlic has attracted considerable attention from scientists. The cloves contain large amounts of sulfur-based substances, which as a consequence of their reactive properties, are converted easily to a variety of volatile compounds during processing. The volatile profiles of processed garlic are influenced by processing conditions, such as temperature, pH and solvent. Numerous studies on these changes in volatile compounds that occur during processing have been reported, with a number of types of sulfur-containing volatile compounds being identified in fresh and processed garlic. This review summarizes the volatile components of fresh and processed garlic, particularly those produced by heating and aging. The pungent odor of fresh garlic is contributed mainly to thiosulfinates and their degradation products. During the heating process of garlic, thiosulfinates are mainly decomposed, and nitrogen-containing volatile compounds, such as pyridines and pyrazines are generated. Aldehydes are dominant compounds in black garlic, while esters and phenols are key aroma compounds in aged garlic extract. The slight variations in chemical reactions during the aging process may lead to differences in the aroma of the two types of garlic. Contents 1. Introduction 2. Volatile components of raw garlic cloves 3. Nature of volatile compounds in garlic cloves during heating 4. Comparison of volatile components between black garlic and aged garlic extract 5. Conclusion

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