Carotenoid accumulation in Japanese apricot (Prunus mume Siebold & Zucc.): molecular analysis of carotenogenic gene expression and ethylene regulation

To elucidate the regulatory mechanisms of carotenogenesis in Japanese apricot (Prunus mume Siebold & Zucc.), the relationships between carotenoid accumulation and the expression of the carotenogenic genes, phytoene synthase (PmPSY-1), phytoene desaturase (PmPDS), zeta-carotene desaturase (PmZDS), lycopene beta-cyclase (PmLCYb), lycopene epsilon-cyclase (PmLCYe), beta-carotene hydroxylase (PmHYb), and zeaxanthin epoxidase (PmZEP), were analyzed in two cultivars with different ripening traits, 'Orihime' and 'Nanko.' In 'Orihime' fruits, large amounts of carotenoids accumulated on the tree, concomitant with the induction of PmPSY-1 and the downstream carotenogenic genes PmLCYb, PmHYb, and PmZEP. In 'Nanko' fruits, carotenoids accumulated mainly after harvest, correlating with an appreciable induction of PmPSY-1 expression, but the downstream genes were not notably induced, which may explain the lower total carotenoid content in 'Nanko' than in 'Orihime.' In both cultivars, a decrease in PmLCYe expression and increased or constant PmLCYb expression could cause the metabolic shift from beta,epsilon-carotenoid synthesis to beta,beta-carotenoid synthesis that occurs as ripening approaches. Next, the effects of ethylene on the expression of PmPSY-1 and carotenoid accumulation were investigated in 'Nanko' fruits treated with propylene or 1-methylcyclopropene (1-MCP). Propylene treatment induced both ethylene production and carotenoid accumulation. PmPSY-1 was constitutively expressed, but propylene treatment accelerated its induction. 1-MCP treatment caused a slight inhibition of carotenoid accumulation along with the repression, although not complete, of PmPSY-1. Collectively, although PmPSY-1 expression was not exclusively regulated by ethylene, both the notable induction of PmPSY-1 accelerated by ethylene and the subsequent induction of the downstream carotenogenic genes, especially PmLCYb, could be necessary for the massive carotenoid accumulation that occurs during ripening. Furthermore, the switch from PmLCYe expression to PmLCYb expression could cause beta,beta-carotenoid accumulation in both Japanese apricot cultivars.     

Chronological observations of Marek's disease-associated feather-pulp lesions in field chickens

Fourteen test groups consisting of a total of 541 field chickens in six rearing farms, all of which were vaccinated with turkey herpesvirus at one day old, were investigated for chronological changes in Marek's disease (MD)-associated feather-pulp lesions (FPL) and their association with nuclear-inclusion (NI) formation in the feather-follicle epithelium (FFE) and with incidence of MD. The FPL observed were categorized into R1-type (non-tumorous lymphoid lesion), R2-type (inflammatory lesion consisting of plasma cellular infiltration, edema or collagenosis of the pulp, and germinal-center formation) and T-type (tumorous lymphoproliferative lesion). In every test group, the incidence of R1-type lesions was highest at 2-4 weeks of age, in spite of the low incidence of NI formation in the FFE. The initial R1-type lesions were generally transitory and were followed occasionally by R2-type lesions. In each test group, incidence of NI formation in the FFE peaked between 9 and 16 weeks of age. The second peak of incidence of R1-type lesions coincided with the period of peak NI formation. Subsequent skin samples revealed that the incidences of R1-, R2-, and T-type lesions in individual chickens or test groups were closely related to the incidence of NI in the FFE and to the incidence of MD.     

Effect of 50 kilobase-plasmid, pKDSC50, of Salmonella choleraesuis RF-1 strain on pig septicemia.

Salmonella choleraesuis strains with and without 50-kilobase plasmid (pKDSC50) were intravenously inoculated into Yorkshire pigs. By the inoculation of 7.2 x 10(5) - 3.5 x 10(7) cells, RF-1 strain with pKDSC50, but not 31N-1 strain without the plasmid, caused a septicemia. The inoculation of 8.7 x 10(9) RF-1 cells killed pigs at 2-4 day postinfection with severe hemorrhage on the whole body. Pigs with a similar number of 31N-1 cells (8.3 x 10(9) cells), showed milder hemorrhage, and they died at 6 day postinfection. These results indicated that pKDSC50 is required for RF-1 strain to express the full virulence causing a heavy cutaneous pig septicemia.     

Transformed phenotypes in long-term cultures persistently infected with bovine leukemia virus.

Two cell lines, 3178 and FLK, were established respectively from calf form bovine lymphosarcoma and from fetal lamb kidney cells inoculated in vitro with bovine leukemia virus. These two cell lines persistently infected with bovine leukemia virus were maintained for more than 150 passages over three years. They exhibited the characteristics of transformed cell lines in vitro: 1) anchorage independence, 2) increased saturation density and decreased population doubling time, 3) increased uptake of 2-deoxy-D-glucose and 4) tumorigenicity in athymic nude mice.     

Increase of methionine aminopeptidase activity in hyperplastic Leydig cells of rat cryptorchid testis: a histochemical study.

Histochemical study on the changes of the aminopeptidase activities in rat testes after surgically-induced cryptorchidism was conducted comparing them with the histochemical changes in regenerated hepatic cells of the partially hepatectomized rat liver. Methionine-aminopeptidase in Leydig cells gradually increased after cryptorchid was induced, whereas the enzyme activity in regenerated hepatic cells decreased. These histochemical observations were coincident with the data obtained by enzyme assay. The present study has indicated that in the rat cryptorchid testis the increase of methionine-aminopeptidase activity was caused by hyperplastic Leydig cells.     

High pore fluid pressure may cause silent slip in the Nankai Trough

Silent-slip events have been detected at several subduction zones, but the cause of these events is unknown. Using seismic imaging, we detected a cause of the Tokai silent slip, which occurred at a presumed fault zone of a great earthquake. The seismic image that we obtained shows a zone of high pore fluid pressure in the subducted oceanic crust located down-dip of a subducted ridge. We propose that these structures effectively extend a region of conditionally stable slips and consequently generate the silent slip.     

High GUS expression in protoplasts isolated from immature peach fruits

A protocol for transient expression analysis was developed using protoplast isolated from immature peach fruits. The uid A gene for β-glucuronidase (GUS) was introduced into the protoplast as a reporter gene to evaluate the protoplast activity. Protoplasts isolated from immature fruits at 28–32 days after full bloom (DAFB) showed high GUS activity under the cauliflower mosaic virus 35S promoter. The highest GUS activity was obtained from the protoplasts isolated at 32 DAFB, but it was difficult to isolate protoplasts showing high GUS activity from 34 DAFB. A comparison of the effect of promoter cassette on gene expression showed that the promoter containing the tobacco mosaic virus Ω sequence enhanced GUS activity by at least 10-fold in the peach protoplasts relative to the 35S promoter. The level of GUS activity under the 35S promoter in the peach protoplasts was 0.47-fold as that obtained from maize protoplasts isolated from young greening leaves, indicating that the GUS activity of immature peach protoplast is sufficient for gene expression analysis. Since stable transformation and evaluation of fruit traits in peach transformants are difficult, this transient expression system could be useful for the characterization of genes expressed in peach and other Rosaceae fruit species.