Uric acid might herald new hopes for multiple sclerosis patients

Uric acid: a natural scavenger of peroxynitrite, in experimental allergic encephalomyelitis and multiple sclerosisHooper, D.C. et al. (1998)Proc. Natl. Acad. Sci. U. S. A. 95, 675–680     

Aspirin as a cancer-preventing drug

Aspirin suppresses the mutator phenotype associated with hereditary nonpolyposis colorectal cancer by genetic selectionRuschoff, J. et al. (1998)Proc. Natl. Acad. Sci. U. S. A. 95, 11301–11306     

Immunochemical detection of the alpha-subunit of the G-protein, GZ, in membranes and cytosols of mammalian cells

An antiserum (AS 98) was raised against a synthetic peptide deduced from published cDNA sequences of the alpha-subunit of the putative G-protein, GZ (Fong et al. Proc. Natl. Acad. Sci. USA 85, 3066-3070, 1988; Matsuoka et al. Proc. Natl. Acad. Sci. USA 85, 5384-5388, 1988). In membrane and cytosol preparations of many but not all tested mammalian tissues, AS 98 predominantly recognized two proteins of 40 and 43 kDa Mr. Whereas high levels of a 40 kDa GZ alpha-subunit were found in rat liver membranes and in brain cytosol, AS 98 failed to detect the alpha-subunit of GZ in brain membranes.     

Control and production of leukotriene B4 in rat tumour and testicular Leydig cells.

Plant mitochondrial ATPase has been chloroform-solubilized and purified by gel filtration from spadices of cuckoo-pint (Arum maculatum). The subunit composition of purified plant and rat liver ATPase were compared by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The delta- and epsilon-subunits of the plant enzyme are larger than their supposed rat liver counterparts and, as such, A. maculatum mitochondrial ATPase shows structural homologies with the enzyme from Escherichia coli [Futai, Sternweis & Heppel (1974) Proc. Natl. Acad. Sci. U.S.A. 71, 2725-2729] rather than with the rat liver enzyme.     

Isolation and characterization of deteriosomes from rat liver

Deteriosomes, a new class of microvesicles, have been isolated from rat liver tissue. These microvesicles are similar to those isolated previously from plant tissue [Yao et al., Proc Natl Acad Sci USA 88:2269–2273, 1991] in that they are nonsedimentable and enriched in membrane catabolites, particularly products of phospholipid degradation. Liver deteriosomes range in size from 0.05 μm to 0.11 μm in radius. They are also much more permeable than microsomal membrane vesicles indicating that the deteriosome bilayer is perturbed. The data are consistent with the proposal that deteriosomes are formed from membranes by microvesiculation and that they represent an intermediate stage of membrane deterioration. Furthermore, liver deteriosomes were found to contain phospholipase A₂ activity. This suggests that they not only serve as a means of moving destabilizing macromolecular catabolites out of membranes into the cytosol but also possess enzymatic activity. The fact that the specific activity of phospholipase A₂ is higher in deteriosomes than in deteriosome-free cytosol suggests that some of the enzymatic activity traditionally assumed to be cytosolic may in fact be associated with deteriosomes.     

Circadian clock and the concept of homeostasis

Comment on: Mercier Zuber A, et al. Proc Natl Acad Sci U S A 2009; In press.     

The regulation of human reproduction by p53 and its pathway

Comment on: Kang HJ, et al. Proc Natl Acad Sci U S A 2009; 106:9761-6.     

Cell-autonomous hepatic circadian clock regulates polyamine synthesis

Comment on: Atwood A, et al. Proc Natl Acad Sci U S A 2011; 108:18560-5.     

Milk, revealed "silent" chemistry: new mode of cycloretinal synthesis

Bovine milk is by far the most commonly consumed milk in the western world. The protein composition in milk consists of casein and whey proteins, of which β-lactoglobulin (BLG) is the principal constituent of the latter. Here we provide biochemical evidence that this milk protein, in purified form and in pasteurized store-bought milk, promotes the formation of cycloretinal (all-trans retinal dimer), and a variety of other cycloterpenals of biological relevance [Fishkin et al., Proc. Natl. Acad. Sci. U. S. A., 2005, 102, 7091-7096; Fishkin et al., Chirality, 2004, 16, 637-641; Kim et al., Proc. Natl. Acad. Sci. U. S. A., 2007, 104, 19273-19278]. Cycloretinal is an eye metabolite and among several toxic byproducts of the visual cycle firmly established to cause age-related macular degeneration. Experiments in rabbits further demonstrate that BLG/milk can survive the digestive system and promote this reaction in vivo [Caillard et al., Am. J. Physiol., 1994, 266(6), G1053-G1059]. Proteomic studies on age-related macular degeneration patients have detected BLG in the eye of these patients further suggesting that this milk protein could contribute to disease progression [Crabb et al., Proc. Natl. Acad. Sci. U. S. A., 2002, 99(23), 14682-14687].     

Rat liver microsomal 3 alpha-hydroxysteroid dehydrogenase and dihydrodiol dehydrogenase: solubilization, separation and partial purification

Rat liver microsomes contain 3 alpha-hydroxysteroid dehydrogenase (HSD) (EC 1.1.1.50) and dihydrodiol dehydrogenase (DHD) (EC 1.3.1.20) activities. The two enzyme activities were solubilized by 10% Triton X-100 or 0.4% sodium deoxycholate. Unlike the cytosolic enzyme (Penning & Talalay (1983) Proc. Natl. Acad. Sci. U.S.A., 80, 4505), the microsomal HSD and DHD activities were not inhibited by indomethacin. Chromatography of the microsomal Triton X-100 extract on Affigel Blue and then on Phenyl-Sepharose gave an HSD preparation containing no detectable (less than 3 - 5%) DHD activity, whereas chromatography of the deoxycholate extract on Phenyl-Sepharose provided a DHD preparation that lacked measurable HSD activity. These results are in sharp contrast to the cytosolic enzyme where both HSD and DHD activities could be copurified to homogeneity (Penning et al. (1984) Biochem. J. 222, 601).     

In the right place at the right time: Analysis of p53 serine 312 phosphorylation in vivo

Comment on: Slee EA, et al. Proc Natl Acad Sci USA 2010; 107:19479–84.     

Glycogen synthase kinase (GSK)-3 and mammalian target of rapamycin complex 1 (mTORC1) cooperate to regulate protein S6 kinase 1 (S6K1)

Comment on: Shin S, et al. Proc Natl Acad Sci USA 2011; 108:1204–13     

Signal sequence of alkaline phosphatase of Escherichia coli.

The amino acid sequence of the signal sequence of phoA was determined by DNA sequencing by using the dideoxy chain termination technique (Sanger et al., Proc. Natl. Acad. Sci. U.S.A. 74:5463-5467, 1977). The template used was single-stranded DNA obtained from M13 on f1 phage derivatives carrying phoA, constructed by in vitro recombination. The results confirm the sequence of the first five amino acids determined by Sarthy et al. (J. Bacteriol. 139:932-939, 1979) and extend the sequence in the same reading frame into the amino terminal region of the mature alkaline phosphatase (Bradshaw et al., Proc. Natl. Acad. Sci. U.S.A., 78:3473-3477, 1981). As was predicted (Inouye and Beckwith, Proc. Natl. Acad. Sci. U.S.A. 74:1440-1444, 1977), the signal sequence was highly hydrophobic. The alteration of DNA sequence was identified for a promoter mutation that results in the expression of phoA independent of the positive control gene phoB and in insensitivity to high phosphate.     

Protein degradation in rat liver during post-natal development.

Protein degradation rates for liver subcellular and submitochondrial fractions from neonatal (8-day), weanling (25-day) and adult rats were estimated by the double-isotope method with NaH14CO3 and [3H] arginine as the radiolabelled precursors [Dice, Walker, Byrne & Cardiel (1978) Proc. Natl. Acad. Sci. U.S.A. 75, 2093-2097]. Decreased protein degradation rates were found during post-natal development for homogenate, nuclear, mitochondrial, lysosomal and microsomal proteins. A decrease in degradation rates for the immunoisolated subunits of monoamine oxidase and pyruvate dehydrogenase was also observed in neonatal and weanling rats respectively. The results suggest coordinate degradation of the subunits of the multi-subunit enzyme pyruvate dehydrogenase. Pyruvate dehydrogenase has a faster rate of degradation in adult rat liver than does cytochrome oxidase. Data analysis suggests heterogeneity of protein degradation rates in the mitochondrial outer membrane and intermembrane space fractions at each developmental stage but not in the mitochondrial inner membrane or matrix fractions. Results obtained for protein degradation rates in adult rat liver by the method of Burgess, Walker & Mayer [(1978) Biochem. J. 176, 919-926] in general confirmed the results obtained for the adult rat liver by the above method. No evidence of a subunit-size relationship for protein degradation was found for proteins in any subcellular or submitochondrial fraction.     

Epstein-Barr virus DNA XII. A variable region of the Epstein-Barr virus genome is included in the P3HR-1 deletion.

The P3HR-1 subclone of Jijoye differs from Jijoye and from other Epstein-Barr virus (EBV)-infected cell lines in that the virus produced by P3HR-1 cultures lacks the ability to growth-transform normal B lymphocytes (Heston et al., Nature (London) 295:160-163, 1982; Miller et al., J. Virol. 18:1071-1080, 1976; Miller et al., Proc. Natl. Acad. Sci. U.S.A. 71:4006-4010, 1974; Ragona et al., Virology 101:553-557, 1980). The P3HR-1 virus was known to be deleted for a region which encodes RNA in latently infected, growth-transformed cells (Bornkamm et al., J. Virol. 35:603-618, 1980; Heller et al., J. Virol. 38:632-648, 1981; King et al., J. Virol. 36:506-518, 1980; Raab-Traub et al., J. Virol. 27:388-398, 1978; van Santen et al., Proc. Natl. Acad. Sci. U.S.A. 78:1930-1934, 1980). This deletion is now more precisely defined. The P3HR-1 genome contains less than 170 base pairs (and possibly none) of the 3,300-base pair U2 region of EBV DNA and is also lacking IR2 (a 123-base pair repeat which is the right boundary of U2). A surprising finding is that EBV isolates vary in part of the U2 region. Two transforming EB viruses, AG876 and Jijoye, are deleted for part of the U2 region including most or all of a fragment, HinfI-c, which encodes part of one of the three more abundant cytoplasmic polyadenylated RNAs of growth-transformed cells (King et al., J. Virol. 36:506-518, 1980; King et al., J. Virol. 38:649-660, 1981; van Santen et al., Proc. Natl. Acad. Sci. U.S.A. 78:1930-1934).     

A new (and different) circadian pacemaker

Comment on: Mohawk JA, Baer ML, Menaker M. The methamphetamine-sensitive circadian oscillator does not employ canonical clock genes. Proc Natl Acad Sci U S A 2009; 106:3519-24.     

Transformation of Azotobacter vinelandii with Plasmids RP4 (IncP-1 Group) and RSF1010 (IncQ Group)

Multicopy plasmid RSF1010 and four of its in vitro-constructed derivatives were mobilized by the self-transmissible RP4 plasmid into Azotobacter vinelandii UW. Modifications of the Escherichia coli transformation procedure of Cohen et al. (Proc. Natl. Acad. Sci. U.S.A. 69:2110–2114, 1972) allowed transformation of A. vinelandii strains UW and ATCC 12837 with purified RP4 or RSF1010 deoxyribonucleic acid.     

Rat sarcoma virus: further analysis of individual viral isolates and the gene product.

Rasheed rat sarcoma virus, derived by in vitro cocultivation of two rat cell lines (Rasheed et al., Proc. Natl. Acad. Sci. U.S.A. 75:2972-2976, 1978), has been reported to code for a protein of 29,000 Mr, immunologically related to the 21,000 Mr src gene product of Harvey and Kirsten sarcoma viruses. Rat sarcoma virus p29 was thought to contain at least part of a rat type C virus structural protein, since antiserum prepared against whole rat virus was able to immunoprecipitate rat sarcoma virus p29 but not Harvey or Kirsten sarcoma virus p21 (Young et al., Proc. Natl. Acad. Sci. U.S.A. 76:3523-3527, 1979). We now report that antiserum directed against rat type C virus p15, but not viral p12, p10, or p27, immunoprecipitated rat sarcoma virus p29. The p15 antiserum was also able to immunoprecipitate both denatured p29 and a peptide derived by V-8 protease cleavage of p29, indicating that this antiserum contains antibodies directed against primary amino acid determinants. Finally, five separate isolates of rat sarcoma virus were found to code for p29, which indicates that a highly specific site of recombination is involved in the generation of sarcoma viruses in rat cells.