Regulated Expression of a Gene-Fusion Product Derived from the Gene for Phytochrome I from Pisum sativum and the uidA Gene from E. coli in Transgenic Petunia hybrida

The 5'-upstream region (2.4 kb) of the gene for phytochromeI from Pisum sativum (phyl) was fused to the uidA gene fromEscherichia coli that encodes ß-glucuronidase (GUS).The resulting PHY-GUS fusion was introduced into Petunia hybridaand was used as a reporter of the expression of the phyI genewhich was recognized by GUS activity. The PHY-GUS fusion wasexpressed at a relatively high level when transgenic plantswere grown in the dark, while leaves and stems of light-grownplants showed background activity. Flowers of light-grown plantswere shown to have significant levels of GUS activity but rootsdid not have such activity. When light-grown transgenic plantswere transferred to the dark, they expressed the activity atlevels that corresponded to those of dark-grown plants. Lighttreatment prior to growth in darkness revealed red/far-red reversibilityof recovery of the activity. Thus, the 2.4-kb fragment fromthe 5' region of the phyI gene carries the information necessaryfor the light-repressible autoregulation. (Received March 30, 1991; Accepted May 20, 1991)     

Wider Retinal Artery Trajectories in Eyes with Macular Hole Than in Fellow Eyes of Patients with Unilateral Idiopathic Macular Hole

Purpose

To determine whether the width of the retinal artery (RA) trajectory was associated with the presence of a macular hole (MH).

Methods

A retrospective cross sectional case-control study was performed. The fundus photographs were rotated 90 degrees, and the coordinates of the best fit curve of the RA trajectory were determined automatically based on these plots using the ImageJ program. The converted coordinates were fit to a second degree polynomial (ax²/100 + bx + c) equation. The width and steepness of the RA trajectory, “a”, of the eyes with a MH eye were compared to that of the fellow eyes.

Results

One hundred and ten eyes of 55 consecutive patients (30 women) with a unilateral MH and healthy fellow eyes were analyzed. The mean age was 64.9 years (range 47-81 years). The constant ‘a’ was significantly smaller in eyes with a MH than that of the fellow eyes (0.379 ± 0.094 vs 0.416 ± 0.121, P = 0.001, paired t test), indicating that the RA trajectory was wider in the MH eyes than in the fellow eyes. There was a significant correlation between the axial length and ‘a’ of the RA trajectory in the MH eyes (R = 0.273, P = 0.044) and in the fellow eyes (R = 0.356, P = 0.008; Spearman’s rank correlation coefficient).

Conclusions

Because eyes with a MH have a significantly wider and flatter RA trajectory, there may be greater traction on the fovea which is located between the RA arches. The causative role of this finding is still unclear.     

Major Factors Affecting Incidence of Childhood Thyroid Cancer in Belarus after the Chernobyl Accident: Do Nitrates in Drinking Water Play a Role?

One of the major health consequences of the Chernobyl Nuclear Power Plant accident in 1986 was a dramatic increase in incidence of thyroid cancer among those who were aged less than 18 years at the time of the accident. This increase has been directly linked in several analytic epidemiological studies to iodine-131 (¹³¹I) thyroid doses received from the accident. However, there remains limited understanding of factors that modify the ¹³¹I-related risk. Focusing on post-Chernobyl pediatric thyroid cancer in Belarus, we reviewed evidence of the effects of radiation, thyroid screening, and iodine deficiency on regional differences in incidence rates of thyroid cancer. We also reviewed current evidence on content of nitrate in groundwater and thyroid cancer risk drawing attention to high levels of nitrates in open well water in several contaminated regions of Belarus, i.e. Gomel and Brest, related to the usage of nitrogen fertilizers. In this hypothesis generating study, based on ecological data and biological plausibility, we suggest that nitrate pollution may modify the radiation-related risk of thyroid cancer contributing to regional differences in rates of pediatric thyroid cancer in Belarus. Analytic epidemiological studies designed to evaluate joint effect of nitrate content in groundwater and radiation present a promising avenue of research and may provide useful insights into etiology of thyroid cancer.     

Genetic Diversity Between Japanese and Chinese Threeline Grunt (<Emphasis Type="Italic">Parapristipoma trilineatum</Emphasis>) Examined by Microsatellite DNA Markers

Threeline grunt (Parapristipoma trilineatum) distributes around the southwestern coast of Japan and the east coast of China. The Chinese P. trilineatum was imported by Japan as an aquacultural seed because of its rapid growth compared with that of the Japanese P. trilineatum. The Japanese P. trilineatum differs from the Chinese P. trilineatum in some quantitative traits, and it has been suggested that these two P. trilineatum populations are genetically different. In order to identify the population structures around Japan and China, 5 local populations of the Japanese P. trilineatum and 2 local populations of the Chinese P. trilineatum were analyzed using 4 microsatellite DNA markers. Significant differences were detected between Japanese and Chinese P. trilineatum and among samples of Chinese P. trilineatum; however, among the samples of Japanese P. trilineatum, no significant differences were detected. These results suggest that care must be taken to prevent the escape of the Chinese P. trilineatum from culture cages around the Japanese coast, in order to preserve the genetically different population structures of Japanese and Chinese P. trilineatum.     

Expression and function of mouse Sox17 gene in the specification of gallbladder/bile-duct progenitors during early foregut morphogenesis

In early-organogenesis-stage mouse embryos, the posteroventral foregut endoderm adjacent to the heart tube gives rise to liver, ventral pancreas and gallbladder. Hepatic and pancreatic primordia become specified in the posterior segment of the ventral foregut endoderm at early somite stages. The mechanisms for demarcating gallbladder and bile duct primordium, however, are poorly understood. Here, we demonstrate that the gallbladder and bile duct progenitors are specified in the paired lateral endoderm domains outside the heart field at almost the same timing as hepatic and pancreatic induction. In the anterior definitive endoderm, Sox17 reactivation occurs in a certain population within the most lateral domains posterolateral to the anterior intestinal portal (AIP) lip on both the left and right sides. During foregut formation, the paired Sox17-positive domains expand ventromedially to merge in the midline of the AIP lip and become localized between the liver and pancreatic primordia. In Sox17-null embryos, these lateral domains are missing, resulting in a complete loss of the gallbladder/bile-duct structure. Chimera analyses revealed that Sox17-null endoderm cells in the posteroventral foregut do not display any gallbladder/bile-duct molecular characters. Our findings show that Sox17 functions cell-autonomously to specify gallbladder/bile-duct in the mouse embryo.     

Establishment of a sandwich ELISA system to detect diapause hormone, and developmental profile of hormone levels in egg and subesophageal ganglion of the silkworm, Bombyx mori

In the silkworm Bombyx mori, diapause hormone (DH) is produced in the female subesophageal ganglion (SG) and induces embryonic diapause by targeting developing ovaries. DH is processed from a precursor protein consisting of DH, pheromone biosynthesis activating neuropeptide (PBAN) and three other neuropeptides (SGNPs). Because these five neuropeptides share a common sequence, FXPRLamide, at the C-terminus, a direct and specific assay for DH itself is required in order to understand the profile of concentration changes. In this study, we produced a mouse monoclonal antibody (anti-DH[N] mAb) against the N-terminal region of DH and developed a sandwich enzyme-linked immunosorbent assay using the anti-DH[N] mAb and a rabbit polyclonal antibody against the C-terminus of DH. This procedure enabled us to specifically quantify the DH molecule at femtomolar levels (equivalent to 1/10 of SG). We then plotted DH levels in eggs and SGs during embryonic and post-embryonic development. DH was present in late-stage embryos that had been destined for the production of both diapause and nondiapause eggs. DH levels in SG gradually increased in both types during larval development and peaked at the early pupal stage. At the middle pupal stage, DH levels in SG and SG-brain complex decreased markedly in the diapause-egg producing type, thus indicating active release of DH into the hemolymph. From 5th instar larva to adult, no sexual differences in DH levels were observed in SGs or SG-brain complexes from diapause and nondiapause egg-producing types.     

Flavonoid composition of fruit tissues of citrus species

An HPLC analysis was performed on the concentrations of flavonoids in 42 species and cultivars of the Citrus genus and those of two Fortunella and one Poncirus species according to the classification system established by Tanaka. The composition of 8 flavanones and 9 flavone/ols for these species was determined in the albedo, flavedo, segment epidermis and juice vesicle tissues, and those in the fruit and peel tissues were calculated from the composition data of the tissues. A principal component analysis showed that such neohesperidosyl flavonoids as neoeriocitrin, naringin, neohesperidin, and rhoifolin had large factor loading values in the first principal component for each tissue. The flavonoid composition of citrus fruits was approximately the same within each section of Tanaka's system, except for the species in the Aurantium section and those with a peculiar flavonoid composition such as Bergamot (C. bergamia), Marsh grapefruit (C. paradisi), Sour orange (C. aurantium), and Shunkokan (C. shunkokan). The Aurantium section included both naringin-rich and hesperidin-rich species.