Localization of the 31-amino-acid endothelin-1 in hamster tissue

Endothelin (ET)-1(1-31) is a novel vasoconstrictor peptide produced by human mast cell chymase, which selectively cleaves big ET-1 at the Try(31)-Gly(32) bond. We investigated the localization of ET-1(1-31) in various hamster tissues by immunohistochemistry and compared it to the distribution of ET-1(1-21). We found that the localization and amount of ET-1(1-31) were different from those of ET-1(1-21) in each tissue. ET-1(1-31)-like immunoreactivities (IR) in the heart, lung, and adrenal gland were observed in the same areas as ET-1(1-21) but were significantly weaker, suggesting that ET-1(1-31) might play a role only in mast cell/chymase-related pathological conditions in these tissues. In the liver, ET-1(1-31)-like IR was strongly detected in Kupffer cells where ET-1(1-21)-like IR was seen more weakly. In the kidney, ET-1(1-31)-like IR was slightly higher than ET-1(1-21). These results suggest that ET-1(1-31) might have physiological roles distinct from those of ET-1(1-21) in some hamster tissues.     

Cloning of the astaxanthin synthase gene from Xanthophyllomyces dendrorhous (Phaffia rhodozyma) and its assignment as a β-carotene 3-hydroxylase/4-ketolase

A gene has been cloned from Xanthophyllomyces dendrorhous by complementation of astaxanthin formation in a β-carotene accumulating mutant. It consists of 3,166 bp and contains 17 introns. For the β-carotene mutant ATCC 96815, a single point mutation in the splicing sequence of intron 8 was found. The resulting improper splicing of the mRNA results in an inactive protein. The cDNA of this β-carotene oxygenase encodes a cytochrome P450 monooxygenase belonging to the 3A subfamily. P450-specific domains were identified including a cytochrome P450 and an oxygen binding motif. Electrons are provided by a cytochrome P450 reductase. Functional characterization of the enzyme by genetic modification of X. dendrorhous demonstrated that this P450 monooxygenase is multifunctional catalyzing all steps from β-carotene to astaxanthin formation by oxygenation of carbon 3 and 4. The reaction sequence is first 4-ketolation of β-carotene followed by 3-hydroxylation. A hydroxylation mechanism at allylic carbon atoms has been proposed for the generation of 4-keto and 3-hydroxy groups at both β-ionone ends.     

Restoration of wetland vegetation using soil seed banks: lessons from a project in Lake Kasumigaura, Japan

The restoration of degraded wetland ecosystems and the recovery of wetland biodiversity are important global issues. Generally, wetland restoration projects include activities to recover vegetation. A promising revegetation technique is one in which soil seed banks are utilized as the source of plant recolonization. Using such a technique, a pilot project to restore lakeshore vegetation was launched at Lake Kasumigaura, Japan, in 2002. In the project, lake sediments containing the seed banks were spread thinly (∼10 cm) on the surfaces of artificial lakeshores, which were constructed in front of concrete levees and had microtopographic variations. In total, 180 species, including six endangered or vulnerable species and 12 native submerged plants that had disappeared from the above-ground vegetation of the lake, were recorded in five recreated lakeshores (total area, 65,200 m²) during the first year of the restoration. The distribution of each restored species at the sites suggested the importance of microtopographic relief for recolonizing species-rich lakeshore vegetation. Furthermore, the origin of the source seed banks affected the species composition of the restored vegetation. On the other hand, the restoration sites were subject to exotic plant invasions. Here, we report lessons learned from the Lake Kasumigaura restoration project as a contribution to the establishment of ecologically sound revegetation techniques.     

The Q223R polymorphism in LEPR is associated with obesity in Pacific Islanders

Various Pacific Island populations have experienced a marked increase in the prevalence of obesity in past decades. This study examined the association of a promoter polymorphism of the leptin gene (LEP), G-2548A (rs7799039), and two non-synonymous single nucleotide polymorphisms of the leptin receptor gene (LEPR), K109R (rs1137100) and Q223R (rs1137101), with body weight, body mass index (BMI) and obesity (BMI ≥ 30) in Pacific Islanders. A total of 745 Austronesian (AN)-speaking participants were analyzed after adjusting for age, gender, and population differences. The results revealed that carriers of the 223Q alleles of LEPR had significantly higher body weight (P = 0.0009) and BMI (P = 0.0022) than non-carriers (i.e., 223R homozygotes); furthermore, the 223Q carriers also had a significantly higher risk of obesity in comparison to non-carriers (P = 0.0222). The other two polymorphisms, G-2548A and K109R, were associated with neither body weight, BMI, nor obesity. The 223Q allele was widely found among the AN-speaking study subjects, thus suggesting that the LEPR Q223R polymorphism is one of the factors contributing to the high prevalence of obesity in the Pacific Island populations.     

Assessing the potential for recovery of lakeshore vegetation: species richness of sediment propagule banks

To assess the potential and develop appropriate techniques for the recolonization of lakeshore vegetation at sites where it had been completely lost, a pilot project was launched at Lake Kasumigaura, Japan. We investigated the species composition and density of the soil seed banks (propagule banks) of lake sediments at nine sites (total area, 65,200 m²) where lake sediments were spread thinly (∼10 cm) on the surfaces of artificial littoral zones. These zones were constructed in front of concrete levees and had microtopographic variations. In total, 180 species, including six endangered or vulnerable species and 12 native submerged plants that had disappeared from the aboveground vegetation of the lake, were recorded during the first year of restoration. The distribution of each restored species at the sites suggested the importance of microtopographic variation for recolonizing species-rich lakeshore vegetation. Furthermore, the origin of the source sediment affected the species composition of the established vegetation.     

Ciborinia gentianae sp. nov., the causal organism of sclerotial flower blight of cut-flower gentians

A new Ciborinia causing sclerotial flower blight of cut-flower gentians (Gentiana triflora var. japonica and interspecific hybrids between related species or varieties) is described as Ciborinia gentianae on the morphological basis of sclerotia and apothecia. The characteristics of Ciborinia gentianae are (1) an abundant production of spermodochia in the hollow cavity of host stems; (2) flat and thin sclerotia produced beneath the epidermis and the inclusion of host vascular remnants within their medulla; (3) globose cells composed of ectal excipulum of apothecia; (4) elongated cells with a slight apical swelling in ectal excipulum at the apothecial margin; and (5) tetra nucleate ascospores. Asci and ascospores mounted in Melzer's reagent measured 156–208 × 8–12 μm and 11.8–15 × 5.5–7.1 μm, respectively.     

Gene trapping in Arabidopsis reveals genes involved in vascular development

The procambium is made up of stem cells that give rise to various vascular cells in plants. To understand the molecular nature of procambium cells, we tried to identify genes that characterize procambium cells using Arabidopsis gene trap lines. Among 26,000 gene trap lines, we found 67 lines in which beta-glucuronidase (GUS) staining occurred along vascular tissues in cotyledons and/or adult leaves. Although four gene trap lines showed procambium-preferential GUS expression, their expression patterns differed from each other during procambium development in root tips and young rosette leaves. Genomic regions flanking the gene trap insertion points in 25 of the 67 lines were determined, including three lines showing preferential GUS staining of the procambium. The three procambium-related genes encoded PINHEAD, katanin and an unknown DUF740 domain-containing protein. We discuss procambium development based on the functions and the differential GUS staining patterns of the procambium-related genes.     

Signal transduction genes required for heterocyst maturation in Anabaena sp. strain PCC 7120

How heterocyst differentiation is regulated, once particular cells start to differentiate, remains largely unknown. Using near-saturation transposon mutagenesis and testing of transposon-tagged loci, we identified three presumptive regulatory genes not previously recognized as being required specifically for normal heterocyst maturation. One of these genes has a hitherto unreported mutant phenotype. Two previously identified regulatory genes were further characterized.