Nitrite Toxicity and Methemoglobin Changes in Southern Flounder,Paralichthys lethostigma,in Brackish Water

This study was performed to estimate the nitrite toxicity to southern flounder, Paralichthys lethostigma, in brackish water (7.5 ppt of salinity). For a LC₅₀ test, 20 fingerlings (5.7 ± 0.4 cm) in each aquarium (15 L) were exposed to the concentrations of 0, 1, 5, 10, 15, 30, 60, 120, and 240 mg NO₂^?‐N/L in duplication for 10 d. Median lethal concentration at 96 h (96‐h LC₅₀) was calculated as 81.6 mg NO₂^?‐N/L. For a verification test, young flounder (164.2 ± 9.1 g) were exposed to a simulated culture condition in recirculating systems (1000 L). Sodium nitrite was not added to control system, whereas it was added to Treatment system 1 (TS 1) and Treatment system 2 (TS 2) to maintain nitrite concentrations of 20 and 30 mg NO₂^?‐N/L, respectively. The plasma nitrite concentrations of the young flounder in TS 1 and TS 2 were 4.5 and 6.6 mg NO₂^?‐N/L, respectively, after 2 wk. At this time, the methemoglobin percentages in TS 1 and TS 2 reached 85.8 and 89.7%, and survival rates were 37.5 and 25.0%, respectively. The results of these tests indicate that southern flounder do not concentrate nitrite in blood from the environment, but they seem to be more sensitive to nitrite compared with other species that do not concentrate nitrite.     

Anti-inflammatory inhibition of endothelial cell adhesion molecule expression by flavone derivatives

Endothelial expression of cell adhesion molecules (CAM) including VCAM-1, E-selectin, and PECAM-1 plays a leading role in atherosclerosis. Phenolic flavones have been shown to have an anti-inflammatory property. This study examines whether 3',4'-dimethoxy-7-hydroxyflavone (methoxyflavone) and 2',3',7-trihydroxyflavone (hydroxyflavone) inhibited monocyte adhesion to TNF-alpha-activated endothelium via reduction of CAM expression in human umbilical vein endothelial cells (HUVEC). In stimulated HUVEC the expression of VCAM-1 and E-selectin was enhanced with increasing mRNA levels. Methoxyflavone markedly interfered with the THP-1 monocyte adhesion to TNF-alpha-stimulated HUVEC. At concentrations of > or =25 microM, methoxyflavone blocked the induction of VCAM-1 but not that of E-selectin on the activated HUVEC. Immunocytochemical staining showed that methoxyflavone modestly inhibited PECAM-1 expression induced by TNF-alpha. In contrast, hydroxyflavone minimally inhibited TNF-alpha-stimulated E-selectin expression without affecting VCAM-1 level. The inhibitory effect of methoxyflavone on THP-1 adhesion to HUVEC appears to be greater than that of hydroxyflavone, most likely due to a greater inhibition of CAM expression. Thus, some flavone derivatives containing methoxy groups may have therapeutic potential attenuating inflammatory response-related atherosclerosis.     

Purification and characterization of hydrolase with chitinase and chitosanase activity from commercial stem bromelain

A hydrolase with chitinase and chitosanase activity was purified from commercial stem bromelain through sequential steps of SP-Sepharose ion-exchange adsorption, HiLoad Superdex 75 gel filtration, HiLoad Q Sepharose ion-exchange chromatography, and Superdex 75 HR gel filtration. The purified hydrolase was homogeneous, as examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme exhibited chitinase activity for hydrolysis of glycol chitin and 4-methylumbelliferyl beta-D-N,N',N' '-triacetylchitotrioside [4-MU-beta-(GlcNAc)(3)] and chitosanase activity for chitosan hydrolysis. For glycol chitin hydrolysis, the enzyme had an optimal pH of 4, an optimal temperature of 60 degrees C, and a K(m) of 0.2 mg/mL. For the 4-MU-beta-(GlcNAc)(3) hydrolysis, the enzyme had an optimal pH of 4 and an optimal temperature of 50 degrees C. For the chitosan hydrolysis, the enzyme had an optimal pH of 3, an optimal temperature of 50 degrees C, and a K(m) of 0.88 mg/mL. For hydrolysis of chitosans with various N-acetyl contents, the enzyme degraded 30-80% deacetylated chitosan most effectively. The enzyme split chitin or chitosan in an endo-manner. The molecular mass of the enzyme estimated by gel filtration was 31.4 kDa, and the isoelectric point estimated by isoelectric focusing electrophoresis was 5.9. Heavy metal ions of Hg(2+) and Ag(+), p-hydroxymercuribenzoic acid, and N-bromosuccinimide significantly inhibited the enzyme activity.     

High-affinity monoclonal antibodies for detection of the microbial metabolite, 2-methylisoborneol

The production of 2-methylisoborneol (MIB) by certain fungi and algae can contribute musty off-flavors to foods and water supplies if uncontrolled. The goal of this research was to develop a nonsensory simple method for the detection of MIB. Anti-MIB monoclonal antibodies were produced by immunizing mice with borneol-conjugated protein and selecting positive clones with an MIB-protein conjugate. An indirect competitive immunoassay developed using this antibody had a detection limit of 0.6 microg L(-)(1) and an I(50) value of 5 microg L(-)(1). Detection was relatively specific for MIB and showed 20% cross-reactivity with borneol or isoborneol and 4-5% cross-reactivity with camphor. No cross-reactivity to geosmin was observed.     

The Physcomitrella genome reveals evolutionary insights into the conquest of land by plants

We report the draft genome sequence of the model moss Physcomitrella patens and compare its features with those of flowering plants, from which it is separated by more than 400 million years, and unicellular aquatic algae. This comparison reveals genomic changes concomitant with the evolutionary movement to land, including a general increase in gene family complexity; loss of genes associated with aquatic environments (e.g., flagellar arms); acquisition of genes for tolerating terrestrial stresses (e.g., variation in temperature and water availability); and the development of the auxin and abscisic acid signaling pathways for coordinating multicellular growth and dehydration response. The Physcomitrella genome provides a resource for phylogenetic inferences about gene function and for experimental analysis of plant processes through this plant's unique facility for reverse genetics.     

Wireless solar water splitting using silicon-based semiconductors and earth-abundant catalysts

We describe the development of solar water-splitting cells comprising earth-abundant elements that operate in near-neutral pH conditions, both with and without connecting wires. The cells consist of a triple junction, amorphous silicon photovoltaic interfaced to hydrogen- and oxygen-evolving catalysts made from an alloy of earth-abundant metals and a cobalt|borate catalyst, respectively. The devices described here carry out the solar-driven water-splitting reaction at efficiencies of 4.7% for a wired configuration and 2.5% for a wireless configuration when illuminated with 1 sun (100 milliwatts per square centimeter) of air mass 1.5 simulated sunlight. Fuel-forming catalysts interfaced with light-harvesting semiconductors afford a pathway to direct solar-to-fuels conversion that captures many of the basic functional elements of a leaf.     

Enzymatic removal of bilirubin from blood: a potential treatment for neonatal jaundice

Current treatments for severe jaundice can result in major complications. Neonatal jaundice is caused by excessive accumulation of bilirubin in the blood. A small blood filter containing immobilized bilirubin oxidase was developed to reduce serum bilirubin concentrations. When human or rat blood was passed through the enzyme filter, more than 90 percent of the bilirubin was degraded in a single pass. This procedure may have important applications in the clinical treatment of neonatal jaundice.     

Evidence of a pluripotent human embryonic stem cell line derived from a cloned blastocyst

Somatic cell nuclear transfer (SCNT) technology has recently been used to generate animals with a common genetic composition. In this study, we report the derivation of a pluripotent embryonic stem (ES) cell line (SCNT-hES-1) from a cloned human blastocyst. The SCNT-hES-1 cells displayed typical ES cell morphology and cell surface markers and were capable of differentiating into embryoid bodies in vitro and of forming teratomas in vivo containing cell derivatives from all three embryonic germ layers in severe combined immunodeficient mice. After continuous proliferation for more than 70 passages, SCNT-hES-1 cells maintained normal karyotypes and were genetically identical to the somatic nuclear donor cells. Although we cannot completely exclude the possibility that the cells had a parthenogenetic origin, imprinting analyses support a SCNT origin of the derived human ES cells.