Genetic structure of korean wild populations of the Medaka Oryzias latipes inferred from allozymic variation

Previous allozymic studies have revealed that Korean wild populations of Oryzias latipes have differentiated regionally, and are composed of two distinct groups, the East Korean Population and the China-West Korean Population. Recently, mitochondrial DNA (mtDNA) sequencing and restriction fragment length polymorphism (RFLP) analyses have confirmed these two groups, and shown that the distribution ranges of the two groups overlap in western Korea. In order to describe the detailed distributions of the two groups and the gene flow between them, genotypes of 13 allozymic loci were determined in 444 specimens from 96 localities in Korea. The two major groups were supported by remarkable allele frequency differences at six diagnostic loci: ACP*, AMY*, CK-A*, LDH-A*, PGM* and TF*. Individuals with the typical "eastern" genotype were mainly distributed in eastern and southern areas. In contrast, fish with the "western" genotype were predominant in the western area, and were further divided into two subgroups (the Han River and Geum River Subpopulations) by unique alleles at the ADH* locus. In the western coast, two distinct (eastern and western) genotypes were distributed in a mosaic fashion. This distribution pattern was identical to those from mtDNA analyses. Although the distribution patterns of the alleles at three loci (GPI-A*, LDH-C* and SOD*) showed introgressive conditions between the two groups, each population was nearly fixed as either the eastern or western genotype at all six diagnostic loci despite the proximity among samples. Therefore, it is suggested that some reproductive isolation mechanisms exist between the two groups in natural habitats.     

Expression of the hepatitis B surface S and preS2 antigens in tubers of <Emphasis Type="Italic">Solanum tuberosum</Emphasis>

In an attempt to develop an edible vaccine, we transformed a recombinant hepatitis B virus (HBV) gene encoding the middle protein of HBV that contains the surface S and preS2 antigen into potato by Agrobacterium-mediated transformation. The HBV gene was under control of either the CaMV 35S promoter, the double 35S promoter with the AlMV 5 non-translated leader sequence, or the tuber-specific patatin promoter. HBV mRNA levels were higher with the 35S promoter than with the double 35S and patatin promoters; however, the levels of the S and preS2 antigen in the transformed tubers were higher with the patatin promoter than with the CaMV 35S and double promoters. The levels of preS2 antigen produced are the highest reported to date. Transgenic potato tubers were fed to mice, and the mice showed an immune response against the HBV S antigen.     

Differentially up-regulated genes in proliferating porcine neonatal pancreas cells caused by epidermal growth factor

Pancreatic duct cells are considered to be a major source for beta-cell regeneration or neogenesis. Although epidermal growth factor (EGF) is a well-known important growth factor for pancreas development, the control of pancreatic duct cell growth and differentiation by EGF is poorly understood. In this study, we focused on identifying the genes that were differentially up-regulated in response to EGF stimulation using monolayer cultured porcine neonatal pancreas cells. Cells were obtained from 1 to 3 day old pigs, dispersed and cultured for 8 days. Monolayer cultured porcine pancreas cells were comprised of duct cells and some endocrine and mesenchymal cells (75.2 +/- 15.1, 19.6 +/- 4.9, and 9.5 +/- 3.1%, respectively). After 16 h in serum free media, cells were treated with 100 microg/L EGF for 24 h. Differentially expressed genes were screened by subtractive hybridization. (3)H-thymidine uptake was significantly increased by EGF with time (untreated vs. 24 h treated, untreated vs. 48 h treated: 305.5 +/- 3.5 cpm vs. 380.3 +/- 17.3 cpm (P < 0.05), 309.2 +/- 4.51 vs. 929 +/- 9.19 cpm, (P < 0.005), respectively). Three hundred and fifty cDNA clones were obtained by subtractive hybridization and the inserts were confirmed in 161 colonies and then sequenced. Finally, we found increased mRNA expression of five unknown and five known genes, including cytochrome c oxidase subunit I (COI), cyclooxygenase-2 (COX-2), matrix metalloproteinase-13 (MMP-13), Wiskott-Aldrich syndrome protein interacting protein (WASPIP), and hyaluronan synthase-2 (HAS-2). We confirmed the up-regulation of these genes by Northern blot and semi-quantitative RT-PCR at various time points. The present findings opened new targets for the research on the mechanisms of pancreatic duct cell proliferation by EGF.     

Identification, evolution, and regulation of expression of Guinea pig trappin with an unusually long transglutaminase substrate domain

Trappins are found in human, bovine, hippopotamus, and members of the pig family, but not in rat and mouse. To clarify the evolution of the trappin genes and the functional significance of their products, we isolated the trappin gene in guinea pig, a species belonging to a rodent family distinct from rat and mouse. Guinea pig trappin was confirmed to encode the same domain structure as trappin, consisting of a signal sequence, an extra large transglutaminase substrate domain, and a whey acidic protein motif. Northern blot analysis and in situ hybridization histochemistry as well as immunohistochemistry demonstrated that guinea pig trappin is expressed solely in the secretory epithelium of the seminal vesicle and that its expression is androgen-dependent. We confirmed that guinea pig trappin is cross-linked by prostate transglutaminase and that the whey acidic protein motif derived from guinea pig trappin has an inhibitory activity against leukocyte elastase. Genome sequence analysis showed that guinea pig trappin belongs to the family of REST (rapidly evolving seminal vesicle transcribed) genes.     

CONSTANS activates SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 through FLOWERING LOCUS T to promote flowering in Arabidopsis

CONSTANS (CO) regulates flowering time by positively regulating expression of two floral integrators, FLOWERING LOCUS T (FT) and SUPPRESSOR OF OVEREXPRESSION OF CO 1 (SOC1), in Arabidopsis (Arabidopsis thaliana). FT and SOC1 have been proposed to act in parallel pathways downstream of CO based on genetic analysis using weak ft alleles, since ft soc1 double mutants showed an additive effect in suppressing the early flowering of CO overexpressor plants. However, this genetic analysis was inconsistent with the sequential induction pattern of FT and SOC1 found in inducible CO overexpressor plants. Hence, to identify genetic interactions of CO, FT, and SOC1, we carried out genetic and expression analyses with a newly isolated T-DNA allele of FT, ft-10. We found that ft-10 almost completely suppressed the early flowering phenotype of CO overexpressor plants, whereas soc1-2 partially suppressed the phenotype, suggesting that FT is the major output of CO. Expression of SOC1 was altered in gain- or loss-of-function mutants of FT, whereas expression of FT remained unchanged in gain- or loss-of-function mutants of SOC1, suggesting that FT positively regulates SOC1 to promote flowering. In addition, inactivation of FT caused down-regulation of SOC1 even in plants overexpressing CO, indicating that FT is required for SOC1 induction by CO. Taken together, these data suggest that CO activates SOC1 through FT to promote flowering in Arabidopsis.     

Environmental effects and desorption characteristics on heavy metal removal using carboxylated alginic acid

Effects of ionic strength and organic materials on copper ion uptake capacity using carboxylated alginic acid which showed very high metal ion uptake capacity were investigated. The ionic strength only had a slight effect on the decrease of copper ion uptake capacity regardless of NaCl concentration. And, the effect of organic materials such as NTA (nitrilotriaceticacid) and sodium hypophosphite on the copper ion uptake capacity was negligible. When the lead ion adsorbed on carboxylated alginic acid was desorbed by NTA, which showed high desorption efficiency, the best optimum concentration of NTA was about 0.01 M. Also desorption efficiency decreased, however, concentration factor increased as S/L ratio which is defined as the ratio of adding amount of adsorbed and volume of desorbing agent increased. In sequential adsorption and desorption cycles, the lead uptake capacity on carboxylated alginic acid was relatively maintained through cycles 1-5.     

Mice with MCH ablation resist diet-induced obesity through strain-specific mechanisms

Genetics and environment contribute to the development of obesity, in both humans and rodents. However, the potential interaction between genes important in energy balance, strain background, and dietary environment has been only minimally explored. We investigated the effects of genetic ablation of melanin-concentrating hormone (MCH), a neuropeptide with a key role in energy balance, with chow and a high-fat diet (HFD) in two different mouse strains, one obesity-prone (C57BL/6) and the other obesity-resistant (129). Substantial differences were seen in wild-type (WT) animals of different strains. 129 animals had significantly lower levels of spontaneous locomotor activity than C57BL/6; however, 129 mice gained less weight on both chow and HFD. In both strains, deletion of MCH led to attenuated weight gain compared with WT counterparts, an effect secondary to increased energy expenditure. In both strains, feeding a HFD led to further increases in energy expenditure in both WT and MCH-KO mice; however, this increase was more pronounced in 129 mice. In addition, mice lacking MCH have a phenotype of increased locomotor activity, an effect also seen in both strains. The relative increase in activity in MCH(-/-) mice is modest in animals fed chow but increases substantially when animals are placed on HFD. These studies reinforce the important role of MCH in energy homeostasis and indicate that MCH is a plausible target for antiobesity therapy.     

Analysis of deforestation patterns in the Baekdudaegan preservation area using land cover classification and change detection techniques; the feasibility of restoration

The Baekdudaegan Mountain Range is a backbone of the Korean Peninsula which has special spiritual and sentimental significance for Koreans and significant ecological value to diverse organisms. Despite the importance of this region, however, the natural environment of Baekdudaegan has been severely threatened by a variety of human activity and tremendous forest fires. To make management and restoration plans for the deforested areas, it is necessary to investigate quantitatively such natural and human-induced physical changes. This study has thus attempted to quantitatively analyze land-use purposes and deforestation patterns in the Baekdudaegan preservation area by taking advantage of on-screen land cover classification and normalized difference vegetation index image-differencing techniques. The study has also attempted to review the feasibility of forest restoration by analyzing the most representative deforestation patterns in the Baekdudaegan preservation area. The land-cover classification results indicated that forests in the Baekdudaegan preservation area occupy an area of 4,794 km², approximately 90% of the total area, and nonforest is approximately 523 km². Agricultural land is the largest portion of nonforest area and occupies an area of 428 km² (82% of the nonforest area); urbanized built-up land accounts for 10% of nonforest areas (50 km²). According to results from change-detection analysis between 1987 and 2000, deforestation occurred in an area of over 240 ha and the dominant causes of deforestation were revealed as expansion of barren land (43% of the deforested area), conversion for agricultural use (34%), expansion of pasture (10%), and urban sprawl (8%). The most devastating deforestation in the Baekdudaegan area was found in agricultural field where the altitude is more than 600 m with a gentle slope of 10–20°. To restore this highland agricultural field, which has expanded along the ridgeline back to healthy forest, it seems the slope faces can be restored without slope stabilization, because the soil is rich and the slope is less than 20°; a landscape ecological approach is, however, suggested to maintain the connectivity of fragmented forest patches.     

Effects of Agitating Culture Condition on the Growth,Metabolic and Carotenoid Profiles of <Emphasis Type="Italic">Lemna paucicostata</Emphasis>

The effects of agitating culture conditions on the growth, metabolic and carotenoid profiles of Lemna paucicostata were investigated in this study using gas chromatography–mass spectrometry and liquid chromatography–mass spectrometry. Lemna paucicostata cultivated under static and agitating conditions showed no significant difference in total plant growth. Various alcohols, amino acids, fatty acids, organic acids, sugars, and phenolic compounds were identified in the sample. The higher relative yields of ferulic acid and GABA were obtained under the agitating condition on day 28, whereas that of coumaric acid was higher under the static condition on day 42. Significantly higher relative yields of antheraxanthin and lutein were achieved under agitation condition than static condition on day 42. In addition, fucoxanthinol was identified for the first time in L. paucicostata culture. The results of this study suggest that static and agitating culture conditions, as well as optimal harvest timing, should be selected according to the target products including ferulic acid, GABA, coumaric acid, antheraxanthin and lutein in L. paucicostata culture.