Dual action of sulforaphane in the regulation of thioredoxin reductase and thioredoxin in human HepG2 and Caco-2 cells

We have previously demonstrated that sulforaphane is a potent inducer for thioredoxin reductase in HepG2 and MCF-7 cells (Zhang et al. Carcinogenesis 2003, 24, 497-503; Wang et al. J. Agric. Food Chem. 2005, 53, 1417-1421). In this study, we have shown that sulforaphane is not only an inducer for thioredoxin reductase but also an inducer for its substrate, thioredoxin in HepG2, and undifferentiated Caco-2 cells. Sulforaphane acts at two levels in the regulation of thioredoxin reductase/thioredoxin system by the upregulation of the expression of both the enzyme and the substrate. In human hepatoma HepG2 cells, sulforaphane induced thioredoxin reductase mRNA and protein by 4- and 2-fold, respectively, whereas thioredoxin mRNA was induced 2.9-fold and thioredoxin protein was unchanged in whole cell extracts, but an increase in nuclear accumulation (1.8-fold) was observed. Moreover, the induction of thioredoxin reductase was found faster than that of thioredoxin. The effects of PI3K and MAPK kinase inhibitors, LY294002, PD98059, SP600125, and SB202190, have been investigated on the sulforaphane-induced expression of thioredoxin reductase and thioredoxin. PD98059 abrogates the sulforaphane-induced thioredoxin reductase at both mRNA and protein levels in HepG2 cells, although other inhibitors were found less effective. However, both PD98059 and LY294002 significantly decrease thioredoxin mRNA expression in HepG2 cells. None of the inhibitors tested were able to modulate the level of expression of either thioredoxin reductase mRNA or protein in Caco-2 cells suggesting that there are cell-specific responses to sulforaphane. In summary, the dietary isothiocyanate, sulforaphane, is important in the regulation of thioredoxin reductase/thioredoxin redox system in cells.     

Acute and chronic gas bubble lesions in cetaceans stranded in the United Kingdom

The first evidence suggestive of in vivo gas bubble formation in cetacea, including eight animals stranded in the UK, has recently been reported. This article presents the pathologic findings from these eight UK-stranded cetaceans and two additional UK-stranded cetacean cases in detail. Hepatic gas-filled cavitary lesions (0.2-6.0 cm diameter) involving approximately 5-90% of the liver volume were found in four (two juvenile, two adult) Risso's dolphins (Grampus griseus), three (two adult, one juvenile) common dolphins (Delphinus delphis), an adult Blainville's beaked whale (Mesoplodon densirostris), and an adult harbour porpoise (Phocoena phocoena). Histopathologic examination of the seven dolphin cases with gross liver cavities revealed variable degrees of pericavitary fibrosis, microscopic, intrahepatic, spherical, nonstaining cavities (typically 50-750 microm in diameter) consistent with gas emboli within distended portal vessels and sinusoids and associated with hepatic tissue compression, hemorrhages, fibrin/organizing thrombi, and foci of acute hepato-cellular necrosis. Two common dolphins also had multiple and bilateral gross renal cavities (2.0-9.0 mm diameter) that, microscopically, were consistent with acute (n = 2) and chronic (n = 1) arterial gas emboli-induced renal infarcts. Microscopic, bubblelike cavities were also found in mesenteric lymph node (n = 4), adrenal (n = 2), spleen (n = 2), pulmonary associated lymph node (n = 1), posterior cervical lymph node (n = 1), and thyroid (n = 1). No bacterial organisms were isolated from five of six cavitated livers and one of one cavitated kidneys. The etiology and pathogenesis of these lesions are not known, although a decompression-related mechanism involving embolism of intestinal gas or de novo gas bubble (emboli) development derived from tissues supersaturated with nitrogen is suspected.     

Identification of a strain of infectious bursal disease virus isolated from mosquitoes.

The Becht strain of infectious bursal disease virus was compared with a virus isolated from Aedes vexans mosquitoes and designed 743 virus. The viruses were compared with respect to cell culture host range, cellular changes resulting from viral infections, growth curves, antigenic relationship, and physicochemical characteristics. The viruses are closely comparable in all these properties, and they are considered to be strains of the same virus. In cross comparisons by the enzyme-linked immunosorbent assay, 743 virus and infectious bursal disease virus were found to be antigenically identical, confirming the results of the neutralization test. The 743 virus differs from most strains of infectious bursal disease virus in that it is nonpathogenic for chickens.     

在玉米豆饼型蛋鸡日粮中使用酶可获益

在过去 2 0年 ,酶在家禽日粮中的使用显著增加。除植酸酶外 ,美国家禽日粮中很少使用酶 ,主要原因是美国使用的以玉米豆饼为主的典型日粮能被家禽很好地利用。不过几种酶产品已推出供蛋鸡日粮使用。玉米的营养价值有时比估计的要低 ,这也表现在不明原因引起蛋鸡生产性能的变异上。玉米淀粉消化率、赖氨酸消化率以及玉米代谢能都有可能发生变化而影响鸡的生产性能。豆饼质量也会变化。加工可减少豆饼中的抗营养因子如胰蛋白酶抑制剂、植物凝集素和果胶 ,但不影响β-甘露聚糖水平 ,高浓度β-甘露聚糖是抗营养的。酶是用来克服抗营养因子的 ,具…