A carotenoid biosynthesis gene cluster for the production of astaxanthin was isolated from the marine bacterium Agrobacterium aurantiacum. This cluster contained five carotenogenic genes with the same orientation, which were designated crtW, crtZ, crtY, crtI, and crtB. The stop codons of individual crt genes except for crtB overlapped the start codons of the following crt genes. Escherichia coli transformants carrying the Erwinia uredovora carotenoid biosynthesis genes provide suitable substrates for carotenoid biosynthesis. The functions of the five crt genes of A. aurantiacum were determined through chromatographic and spectroscopic analyses of the pigments accumulated in some E. coli transformants carrying various combinations of the E. uredovora and A. aurantiacum carotenogenic genes. As a result, the astaxanthin biosynthetic pathway is proposed for the first time at the level of the biosynthesis genes. The crtW and crtZ gene products, which mediated the oxygenation reactions from ␤-carotene to astaxanthin, were found to have low substrate specificity. This allowed the production of many presumed intermediates of astaxanthin, i.e., adonixanthin, phoenicoxanthin (adonirubin), canthaxanthin, 3-hydroxyechinenone, and 3-hydroxyechinenone.During the last 6 years, significant advances have been made in our understanding of the genes coding for the enzymes involved in carotenoid biosynthesis. Many carotenoid biosynthesis genes have been cloned from various organisms, and their functions have been determined (3, 54, 62). Phytoene synthase genes, which mediate the formation of the first colorless carotenoid phytoene from geranylgeranyl PP i (GGPP) (11,46,55), have been isolated from the photosynthetic bacteria Rhodobacter species (5, 31), the nonphotosynthetic bacteria Erwinia species (4,45,60) and Thermus thermophilus (20), the cyanobacterium Synechococcus sp. strain PCC7942 (11), the fungus Neurospora crassa (57), and higher plants (7,50,51,58). Many genes involved in the desaturation (dehydrogenation) steps to convert phytoene to -carotene, neurosporene, or lycopene have also been obtained from the photosynthetic bacteria Rhodobacter species (5, 6, 31), the nonphotosynthetic bacteria Erwinia species (4, 45, 60) and Myxococcus xanthus (16), the cyanobacterium Synechococcus sp. strain PCC7942 (12), the fungi N. crassa (56) and Cercospora nicotianae (15), and higher plants (8,21,48). A second desaturase gene, which mediates the desaturation reaction from -carotene to lycopene, has been obtained from the cyanobacterium Anabaena sp. strain PCC7120 (33). The genes coding for lycopene cyclase, which catalyzes the formation of a cyclic carotenoid ␤-carotene from lycopene, have been isolated from the nonphotosynthetic bacteria Erwinia species (25, 45) and the cyanobacterium Synechococcus sp. strain PCC7942 (14).Among these organisms, the carotenoid biosynthesis genes of the yellow-pigmented nonphotosynthetic soil bacteria Erwinia uredovora (45) and Erwinia herbicola (4, 22, 60) have been used most frequently in the study o...

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Although the functional effect of alcohol dehydrogenase 2 (ADH2) His 47 Arg polymorphism has been elucidated, its effect on habitual drinking remains unknown. Here, we conducted a cross-sectional study in 2,299 nonalcoholic Japanese subjects (989 men and 1,310 women). Drinking status, ethanol consumption, and physical reaction to one glass of beer were examined with regard to ADH2 and aldehyde dehydrogenase 2 (ALDH2) polymorphism. Strength of associations were assessed by age-, sex-, smoking status-, and genotype-adjusted odds ratios and their 95% confidence intervals. ADH2 His/Arg and Arg/Arg genotypes showed higher risk for habitual drinking. Among men, ALDH2 genotype-and confounder-adjusted odds ratios (95% confidence intervals) were 1.30 (0.89-1.89) and 3.16(1.03-9.70), and this trend was significant (P = 0.024). A similar trend was observed among women. The combination genotypes of two polymorphisms revealed the clear effect of the ADH2 Arg allele among those with ALDH2 Glu/Lys in both sexes (P trend = 0.007 for men and 0.024 for women). Physical reactions, such as flushing and palpitation, were significantly less common in those with Arg/Arg compared with other ADH2 genotypes, and this was marked when combined with ALDH2 Glu/Lys. Heavy drinker status was also strongly associated with ADH2 Arg alleles. In conclusion, this study showed the strong effect of ADH2 His

Associations between Key words: Helicobacter pylori infection -Interleukin 1 -Lifestyle factorsHelicobacter pylori (HP) infection, a well-known risk factor for stomach cancer, depends largely on sanitary conditions, especially in childhood. [1][2][3] There are still substantial differences in childhood prevalence between developed and developing countries, ranging from 4% to 82% reportedly.2) An increase in infected individuals with age is observed in many developed countries, which is considered to be due to a cohort effect. 1) Although there is no doubt that exposure to the bacterium increases the infection rate in the population, host susceptibility is also an important factor. Even after an ordinary level of HP exposure, uninfected persons still seem to exist in any population. In addition, spontaneous eradication after childhood infection may be influenced by host factors.Polymorphisms of interleukin-1β gene (IL-1B) and interleukin 1 receptor antagonist gene (IL-1RN) were reportedly associated with stomach cancer risk for a population from Poland. 4) IL-1β is a pro-inflammatory cytokine with multiple biological effects, 5) and is induced by HP infection.6) IL-1B has three diallelic polymorphisms at −511, −31, and 3954 base pairs (bp) from the transcriptional start site. Though the differences were not statistically significant, persistent HP infection was observed for 60% of individuals harboring the C/C genotype (n=58) at −31 of IL-1B, for 73% of those with the C/T genotype (n=67), and for 79% of those with the T/T genotype (n=24) in a population from Scotland.4) The T allele at −31 forms a TATA box, suspected of enhancing gene expression. The study reported that the polymorphism at −511 linked tightly with the polymorphism at −31, and therefore quite similar findings on the risks of stomach cancer and HP infection were obtained for IL-1B C−511T. The polymorphism at 3954 was not associated with the risks of stomach cancer and HP infection in the study.4) IL-1RN has a penta-allelic 86-bp tandem repeat polymorphism in intron 2, which was found to affect IL-1β production in vitro, 7) but it was not associated with HP infection. 4) IL-1α is another member of IL-1, which is encoded by IL-1A. It is primarily a cytosolic cytokine. About 10% or 15% is myristoylated and transported to the cell surface (membrane IL-1), but it is not detected in the serum under normal conditions. 5) IL-1A was reported to have three polymorphisms; C−889T, 46-bp variable number of tandem 6 To whom correspondence should be addressed.

Smad family members are essential intracellular signaling components of the transforming growth factor-beta (TGF-b) superfamily involved in a range of biological activities. Two highly homologous molecules, Smad2 and Smad3, have so far been identi®ed as receptor-activated Smads for TGF-b signaling and have become the focus of intensive studies. However, no de®nite di erences in regulation or function have been established between these TGF-b signaling molecules. In the present study, we show that the expression of Smad3, but not its close relative, Smad2, is down-regulated by TGF-b mediated signals themselves in human lung epithelial cells. This down-regulation of Smad3 by TGF-b treatment did not appear to result from shortening of the half-life of Smad3 mRNA. Constitutive expression of Smad3 in the presence of TGF-b induced apoptotic cell death, with an adverse e ect on the cell growth of human lung epithelial cells. Apoptotic cell death could also be induced by forced expression of Smad2 in the presence of TGF-b, but less e ciently than by that of Smad3. These ®ndings clearly de®ne the distinctions between Smad2 and Smad3 for the ®rst time in that a qualitative di erence was observed with regard to the regulation of their expression in response to TGF-b, while Smad2 and Smad3 appeared to have quantitatively di erent capabilities regarding the induction of apoptotic cell death in human lung epithelial cells.