Femoral artery neointimal hyperplasia is reduced after wire injury in Ref-1+/- mice

Redox factor-1 (Ref-1) is a multifunctional protein that regulates redox, DNA repair, and the response to cell stress. We previously demonstrated that Ref-1(+/-) mice exhibit a significantly reduced Ref-1 mRNA and protein levels within the vasculature, which are associated with increased oxidative stress. The goal of this study was to test the hypothesis that partial loss of Ref-1 altered the cellular response to vascular injury. Fourteen days after femoral artery wire injury, we found that vessel intima-to-media ratio was significantly reduced in Ref-1(+/-) mice compared with that in wild-type mice (P < 0.01). Bromodeoxyuridine labeling and transferase-mediated dUTP nick-end labeling staining at 14 days did not differ in the Ref-1(+/-) mice. In vitro studies found no significant changes in either serum-induced proliferation or baseline apoptosis in Ref-1(+/-) vascular smooth muscle cells. Exposure to Fas ligand; however, did result in increased susceptibility of Ref-1(+/-) vascular smooth muscle cells to apoptosis (P < 0.001). Ref-1(+/-) mice exhibited an increase in circulating baseline levels of IL-10, IL-1alpha, and VEGF compared with those in wild-type mice but a marked impairment in these pathways in response to injury. In sum, loss of a single allele of Ref-1 is sufficient to reduce intimal lesion formation and to alter circulating cytokine and growth factor expression.     

Effects of cardiogenic edema fluid on ion and fluid transport in the adult lung

We have previously shown that cardiogenic pulmonary edema fluid (EF) increases Na(+) and fluid transport by fetal distal lung epithelia (FDLE) (Rafii B, Gillie DJ, Sulowski C, Hannam V, Cheung T, Otulakowski G, Barker PM and O'Brodovich H. J Physiol 544: 537-548, 2002). We now report the effect of EF on Na(+) and fluid transport by the adult lung. We first studied primary cultures of adult type II (ATII) epithelium and found that overnight exposure to EF increased Na(+) transport, and this effect was mainly due to factors other than catecholamines. Plasma did not stimulate Na(+) transport in ATII. Purification of EF demonstrated that at least some agent(s) responsible for the amiloride-insensitive component resided within the globulin fraction. ATII exposed to globulins demonstrated a conversion of amiloride-sensitive short-circuit current (I(sc)) to amiloride-insensitive I(sc) with no increase in total I(sc). Patch-clamp studies showed that ATII exposed to EF for 18 h had increased the number of highly selective Na(+) channels in their apical membrane. In situ acute exposure to EF increased the open probability of Na(+)-permeant ion channels in ATII within rat lung slices. EF did increase, by amiloride-sensitive pathways, the alveolar fluid clearance from the lungs of adult rats. We conclude that cardiogenic EF increases Na(+) transport by adult lung epithelia in primary cell culture, in situ and in vivo.     

Current Status of Our Understanding for Brain Integrated Functions and its Energetics

Neurochemical Research - Human/animal brain is a unique organ with substantially high metabolism but it contains no energy reserve that is the reason it requires continuous supply of O2 and energy...     

Cxcl12 evolution--subfunctionalization of a ligand through altered interaction with the chemokine receptor

The active migration of primordial germ cells (PGCs) from their site of specification towards their target is a valuable model for investigating directed cell migration within the complex environment of the developing embryo. In several vertebrates, PGC migration is guided by Cxcl12, a member of the chemokine superfamily. Interestingly, two distinct Cxcl12 paralogs are expressed in zebrafish embryos and contribute to the chemotattractive landscape. Although this offers versatility in the use of chemokine signals, it also requires a mechanism through which migrating cells prioritize the relevant cues that they encounter. Here, we show that PGCs respond preferentially to one of the paralogs and define the molecular basis for this biased behavior. We find that a single amino acid exchange switches the relative affinity of the Cxcl12 ligands for one of the duplicated Cxcr4 receptors, thereby determining the functional specialization of each chemokine that elicits a distinct function in a distinct process. This scenario represents an example of protein subfunctionalization--the specialization of two gene copies to perform complementary functions following gene duplication--which in this case is based on receptor-ligand interaction. Such specialization increases the complexity and flexibility of chemokine signaling in controlling concurrent developmental processes.     

Technoeconomic analysis of five microalgae-to-biofuels processes of varying complexity

The economics surrounding five algae-to-fuels process scenarios were examined. The different processes modeled were as follows: an open pond producing either triacylglycerides (TAG) or free fatty acid methyl ester (FAME), a solar-lit photobioreactor producing either FAME or free fatty acids (FFA), and a light emitting diode irradiated (LED-lighted) photobioreactor producing TAG. These processes were chosen to represent both classical and esoteric approaches presented in the open literature. Viable (or suggested) processing techniques to liberate and purify (and convert) the microalgal triacylglycerides were then modeled to accompany each growth option. The investment and cost per kg of fuel or fuel precursor for each process was determined. The open pond produced TAG at ～$7.50/kg, while the process using the LED-lit photobioreactor produced TAG at ～$33/kg. The scenario containing the solar-lit photobioreactor produced FAME at ～$25/kg, while the open pond produced FAME at ～$4/kg. The scenario containing the solar-lit photobioreactor produced FFA at ～$29/kg. The open pond scenarios appear to be closest to the $1/kg pricepoint at this time, and thus are the most viable economic options. Future technological advancements that reduce the cost of bioreactor vessels, LED lighting, and solvent recovery, may reduce the oil production costs of these scenarios to a more attractive level.     

Improvement in HPLC separation of acetic acid and levulinic acid in the profiling of biomass hydrolysate

5-Hydroxymethylfurfural (HMF) and furfural could be separated by the Aminex HPX-87H column chromatography, however, the separation and quantification of acetic acid and levulinic acid in biomass hydrolysate have been difficult with this method. In present study, the HPLC separation of acetic acid and levulinic acid on Aminex HPX-87H column has been investigated by varying column temperature, flow rate, and sulfuric acid content in the mobile phase.The column temperature was found critical in resolving acetic acid and levulinic acid. The resolution for two acids increased dramatically from 0.42 to 1.86 when the column temperature was lowered from 60 to 30 °C. So did the capacity factors for levulinic acid that was increased from 1.20 to 1.44 as the column temperature dropped. The optimum column temperature for the separation was found at 45 °C. Variation in flow rate and sulfuric acid concentration improved not as much as the column temperature did.     

GUN4-porphyrin complexes bind the ChlH/GUN5 subunit of Mg-Chelatase and promote chlorophyll biosynthesis in Arabidopsis

The GENOMES UNCOUPLED4 (GUN4) protein stimulates chlorophyll biosynthesis by activating Mg-chelatase, the enzyme that commits protoporphyrin IX to chlorophyll biosynthesis. This stimulation depends on GUN4 binding the ChlH subunit of Mg-chelatase and the porphyrin substrate and product of Mg-chelatase. After binding porphyrins, GUN4 associates more stably with chloroplast membranes and was proposed to promote interactions between ChlH and chloroplast membranes—the site of Mg-chelatase activity. GUN4 was also proposed to attenuate the production of reactive oxygen species (ROS) by binding and shielding light-exposed porphyrins from collisions with O₂. To test these proposals, we first engineered Arabidopsis thaliana plants that express only porphyrin binding–deficient forms of GUN4. Using these transgenic plants and particular mutants, we found that the porphyrin binding activity of GUN4 and Mg-chelatase contribute to the accumulation of chlorophyll, GUN4, and Mg-chelatase subunits. Also, we found that the porphyrin binding activity of GUN4 and Mg-chelatase affect the associations of GUN4 and ChlH with chloroplast membranes and have various effects on the expression of ROS-inducible genes. Based on our findings, we conclude that ChlH and GUN4 use distinct mechanisms to associate with chloroplast membranes and that mutant alleles of GUN4 and Mg-chelatase genes cause sensitivity to intense light by a mechanism that is potentially complex.