Effect of nutrient intake on intramuscular glucose metabolism during the early growth stage in cross-bred steers (Japanese Black male × Holstein female).

The objective was to investigate the impact of nutrient intake during the early growth period on the expression of glucose metabolism-related genes in skeletal muscle of cross-bred cattle. From 1.5 to 5 months of age, group H (n=7) animals were intensively fed a high-protein and low-fat milk replacer [crude protein (CP) 28%; ether extracts (EE) 18%; max: 2.0 kg, 12 l/day], and group R (n=7) animals were fed a restricted amount of normal milk replacer (CP 25%; EE 23%; max 0.5 kg, 4 l/day). From 6 to 10 months of age, group H cattle were fed a high-nutrition total mixed ration mainly prepared from grain feed, and group R cattle were fed only roughage. Blood samples were taken from each animal at three biopsy times (1.5, 5 and 10 months of age), and the blood plasma concentration of glucose and insulin was analysed. In glucose concentration, there were no significant differences; however, the concentrations of insulin were higher in group H than in group R at 5 and 10 months of age. Muscle samples were taken by biopsy from longissimus thoracis muscle (LT) at 1.5, 5 and 10 months of age. We analysed mRNA expression levels using the quantitative real-time polymerase chain reaction (PCR) assay for glucose transporters (GLUT1 and GLUT4), insulin receptor, phosphatidylinositol 3-kinase (PI-3K), protein kinase B (PKB, also known as Akt), hexokinase 1 (HK1) and tumour necrosis factor alpha (TNFα). Although no differences were detected at 1.5 and 5 months of age, at 10 months of age, GLUT1, HK1 and TNFα mRNA expression levels were significantly higher in group H than in group R. These results suggested Glut1 that affects insulin-independently mediated glucose uptake was more responsive to improved nutrition during early growth stage than GLUT4 that insulin-dependently mediated glucose uptake in LT of cattle.

Reconstruction for the brilliance-upgrading project of the Photon Factory storage ring.

Reconstruction of the Photon Factory storage ring (PF ring; 2.5 GeV) is now in progress to provide very brilliant synchrotron radiation to users, i.e. the emittance is being reduced by a factor of five. Components, such as the quadrupole and sextupole magnets, vacuum chambers, beamlines and beam-position monitors, are being replaced by new ones in 16 normal-cell sections of the PF ring. The accelerating cavities, injection systems and control systems are also being replaced. Operation will commence when the improvements are completed on 1 October 1997.

Operational evaluation of ultrahigh-vacuum protection systems for intense-photon-flux wiggler beamlines.

The ultrahigh-vacuum (UHV) protection system at the 2.5 GeV synchrotron radiation source (positron storage ring) at the Photon Factory allows the intense-photon-flux wiggler beamlines to operate safely during synchrotron radiation experiments for a long time. There are six high-power wiggler/undulator beamlines that provide intense photon-flux beams to the experimental hall. In the case of a possible instantaneous vacuum failure at the experimental hall, the intense photon-flux radiation from the wiggler could cause a meltdown of the titanium-alloy fast-closing valve. The authors have developed a UHV protection system. Upon a vacuum failure, the protection system can dump the positron beam by turning off the RF power in the four RF klystrons (150 kW maximum), and then initiate a blade closure of the fast-closing valve. In this paper, the operational performance of the vacuum protection system for the intense-photon-flux wiggler beamlines is evaluated and discussed regarding the actual vacuum deterioration downstream of a beamline at the experimental hall.

Characterization of the gcd gene from Escherichia coli K-12 W3110 and regulation of its expression.

DNA sequence and expressional analyses of the gcd gene of Escherichia coli K-12 W3110 revealed that two promoters that were detected were regulated negatively by cyclic AMP and positively by oxygen. Sequence conservation of the gcd gene between E. coli K-12 W3110 and PPA42 suggests that glucose dehydrogenase is required for the E. coli cells, even though it ordinarily exists as an apoprotein.

High incidence of angiosarcomas in brown-fat tissue and livers of mice fed sterigmatocystin.

BDF1 female mice fed 30 or 120 ppm sterigmatocystin in their diet for 55 or 51 wk, respectively, developed angiosarcomas of the liver and of the dorsal brown-fat tissue. No tumours were observed in five mice from each group, including the controls, killed after 43 wk, but angiosarcomas were observed in mice from the test groups that died or were killed after more than 43 wk of treatment with sterigmatocystin. Thirty-four out of 53 mice (64.2%) fed 30 ppm sterigmatocystin developed hepatic angiosarcomas. Six (11.3%) of those fed 30 ppm sterigmatocystin and 27 out of the 51 mice (52.9%) fed 120 ppm developed angiosarcomas in the dorsal brown-fat tissue. Benign vascular lesions in the liver and a few angiosarcomas of the ovary and lung were also observed in mice of both test groups. No vascular changes were observed in control mice except for peliosis-like lesions in the spleens of two mice. Increases in the incidences of lung and hepatocellular adenomas were also observed in sterigmatocystin-treated mice.