Photoinduced water splitting with oxotitanium tetraphenylporphyrin.

Photocatalytic splitting of water was investigated in a heterogeneous system consisting of micro-crystallites of oxotitanium tetraphenylporphyrin deposited on fused silica plates, immersed in water and excited within the visible range of their absorption spectra. The water photolysis was evidenced by the spectroscopic detection of hydroxyl radicals generated in the reaction. The experimental results confirm the mechanism of water splitting and generation of OH˙ radicals proposed theoretically by Sobolewski and Domcke [Phys. Chem. Chem. Phys., 2012, 14, 12807] for the oxotitaniumporphyrin-water complex. It is shown that photocatalytic water splitting occurs in pure water, and neither pH-bias nor external voltage is required to promote the reaction.

Automated analysis of viral integration sites in gene therapy research using the SeqMap web resource.

Research in gene therapy involving genome-integrating vectors now often includes analysis of vector integration sites across the genome using methods such as ligation-mediated PCR (LM-PCR) or linear amplification-mediated PCR (LAM-PCR). To help researchers analyze these sites and the functions of nearby genes, we have developed SeqMap (http://seqmap.compbio.iupui.edu/) a secure, web-based comprehensive vector integration site management tool that automatically analyzes and annotates large numbers of vector integration sites derived from LM-PCR experiments in human and model organisms upon a common genome database. We believe the use of this resource will enable better reproducibility and understanding of this important data.

Modulation of glutamine uptake and phosphate-activated glutaminase activity in rat brain mitochondria by amino acids and their synthetic analogues.

Uptake of L-[14C]Gln and phosphate-activated glutaminase (PAG) activity were measured in nonsynaptic mitochondria isolated from rat cerebral hemispheres, in the presence of protein and nonprotein amino acids and their synthetic structural analogues and derivatives. The uptake was inhibited by > 50% in the presence of a 10-fold excess of His, homocysteine (Hcy), Trp, Leu, Tyr, Ile, Thr, Ala, Phe, Met, Ser, by > 20% in the presence of a 10-fold excess of Val, Arg, Glu, and was not affected by a 10-fold excess of Orn, alpha-ketoglutarate, Tau and Pro. Uptake of L-[14C] Leu differed from Gln uptake by its resistance to Arg, Glu, and a relatively high sensitivity to the reference inhibitor of the plasma membrane transport of large neutral amino acids (L-system)--BCH (2-aminobicyclo[2.2.1]heptane-2-carboxylic acid), and a number of natural L-system substrates. A newly synthesized alanine analogue, 2'-cyano-(biphenyl) alanine, referred to as MRC01, was the only compound tested that inhibited Gln uptake more strongly than Leu uptake. The strongest Gln uptake inhibitors: MRC01, His, Hcy and Leu, inhibited PAG activity by > 50% when added at the inhibitor/Gln concentration ratio of 1:2. PAG activity was not affected by Tau, Lys or Pro, compounds which did affect Gln uptake. The results suggest that a number of natural amino acids function as common endogenous modulators of cerebral mitochondrial Gln uptake and its degradation. MRC01, because of its inhibitory potency towards both mitochondrial Gln uptake and PAG activity, may become a convenient tool in studying the role of Gln transport in its mitochondrial metabolism in intact CNS cell and tissues.

Propofol versus midazolam for sedation during percutaneous transluminal angioplasty.

PURPOSE: To prospectively and randomly compare use of propofol versus midazolam for sedation during percutaneous transluminal angioplasty (PTA). MATERIALS AND METHODS: Forty patients (27 men, 13 women; mean age 64.4 years +/- 12.2) who underwent PTA of the arteries below the diaphragm were prospectively randomized for sedation with propofol or midazolam. Both drugs were administered after an initial bolus injection by means of continuous infusion to achieve conscious sedation at levels II-III according to the Ramsay classification. Patients and interventionalists were blinded to the applied sedative. Both groups were similar with regard to American Society of Anesthesiology status, heart rate, blood pressure, arterial oxygen pressure (pO2), arterial carbon dioxide pressure (pCO2), arterial oxygen saturation (SpO2), and visual analogue scores for general condition, anxiety, and pain. During PTA, heart rate, blood pressure, and pulse oximetry (tpO2) were monitored continually. Every 30 minutes, an arterial blood gas analysis was performed. Visual analogue scores were obtained before, during, and after intervention. RESULTS: Decreases in SpO2, pO2, and tpO2 were significantly greater after sedation with midazolam (P < .05; t test). The increase in pCO2 was significantly greater after midazolam (P < .05; t test). No significant difference between the drugs was found with regard to any of the other parameters. Both drugs resulted in sufficient sedation and anxiolysis (P < .01 for both drugs for visual analogue score for anxiety before and during PTA; matched pairs test). Satisfaction of the interventionalist was significantly greater for propofol (P < .05; t test). CONCLUSION: Propofol causes less respiratory depression than midazolam for equivalent sedation and anxiolysis in patients undergoing PTA.

Myo-Inositol Esters of Indole-3-acetic Acid as Seed Auxin Precursors of Zea mays L.

Indole-3-acetyl-myo-inositol esters constitute 30% of the low molecular weight derivatives of indole-3-acetic acid (IAA) in seeds of Zea mays. [(14)C]Indole-3-acetyl-myo-inositol was applied to a cut in the endosperm of the seed and found to be transported from endosperm to shoot at 400 times the rate of transport of free IAA. The rate of transport of indole-3-acetyl-myo-inositol from endosperm to shoot was 6.3 picomoles per shoot per hour and thus adequate to serve as the seed auxin precursor for the free IAA diffusing downward from the shoot tip. Indole-3-acetyl-myo-inositol is the first seed auxin precursor to be identified.Application of either [(14)C]IAA or (14)C-indole-3-acetyl-myo-inositol ester to the endosperm results in both free and esterified [(14)C]IAA in the seedling shoot. Esterification of free IAA and hydrolysis of indole-3-acetyl-myo-inositol occurred in the shoot and not the endosperm yielding ratios of ester to free IAA which approximate the ratios of ester to free IAA normally found in corn shoot tissue. This proves, for the first time, that esterified IAA and free IAA are interconvertible in the growing shoot. Since free IAA may be limiting for plant growth, knowledge that the free hormone is in "equilibrium" with its conjugates suggests new methods for the control of plant growth.

Stoicheiometrical proton and potassium ion movements accompanying the absorption of amino acids by the yeast Saccharomyces carlsbergensis.

1. Proton uptake into the yeast Saccharomyces carlsbergensis, was studied at pH4.5-5.5 in the presence of both antimycin and 2-deoxyglucose to inhibit energy metabolism. Previous work had shown that the cells then absorbed about 20nmol of glycine or l-phenylalanine against a considerable amino acid concentration gradient. The addition of the amino acid immediately stimulated the rate of uptake of protons two- to three-fold. About 2 extra equivalents of H(+) accompanied a given amount of the amino acids into the yeast preparations exposed to the metabolic inhibitors for 2-4min and about 1.2 equivalents after 20min exposure. 2. Analogous observations were made during serial additions of glycine, l-phenylalanine, l-leucine and l-lysine to preparations lacking the metabolic inhibitors and deficient in substrates needed for energy metabolism. In fresh cellular preparations the influx of glycine was then closely coupled to a stimulated flow of 2.1 equiv. of H(+) into the yeast. A similar number of K(+) ions left the cells. About 30% of the extra protons was subsequently ejected from the yeast. Deoxyglucose and antimycin together inhibited the ejection of protons. When the yeast had been fed with glucose energy metabolism was stimulated and almost as many protons as were absorbed with the amino acid were apparently ejected again. 3. Yeast preparations containing Na(+), instead of K(+), as the principal cation absorbed about 1 extra equivalent of H(+) after the addition of phenylalanine, glycine or leucine. This response was not observed in the presence of both deoxyglucose and antimycin. 4. The observations show that H(+) and, in certain circumstances, K(+) are co-substrates in the transport of the amino acids into the yeast. An analogy is drawn with the roles of Na(+) and K(+) as co-substrates in certain mammalian systems. The results lead to various models relating the physical flow of the co-substrate ions on the amino acid carrier to the transduction of chemical energy in an associated ion pump forming part of the mechanism for transporting amino acids into the yeast.

Interctions between potassium ions and glycine transport in the yeast Saccharomyces carlsbergensis.

A study has been made of the effects of both varying the pH and extracellular [K(+)] on the initial rate of uptake of glycine (v) by a strain of Saccharomyces carlsbergensis that concentrated the amino acid, with respect to the extracellular phase, by up to 1400 times. When no other substrate than glycine was provided and [glycine] was relatively small (