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European Journal of Biochemistry May 1986Phosphorus-31 nuclear magnetic resonance (NMR) spectra were recorded from freshly excised and resting anterior byssus retractor muscles of the mussel Mytilus edulis. The...
Phosphorus-31 nuclear magnetic resonance (NMR) spectra were recorded from freshly excised and resting anterior byssus retractor muscles of the mussel Mytilus edulis. The absolute concentrations of phosphometabolites measured by NMR compare well with the values obtained by a biochemical method. Quantitative measurements were achieved in several minutes by applying to the observed NMR signals a correction taking the saturation effects into account. The time evolution of the phosphometabolite concentrations reveals that the hydrolysis of phosphoarginine is a first-order reaction producing inorganic phosphate, whilst the adenosine triphosphate level remains constant for more than 10 h. The phosphoarginine hydrolysis rate varies as a function of the season and reaches a maximum during the reproduction period of the mussel. This increase in phosphoarginine consumption could be bound up with the higher excitability of the muscles during spring. The activation energy of the phosphoarginine hydrolysis reaction also depends on the season and the difference between the value determined in winter and that measured in spring is explained by a modification of the mode of action or of the proportions of the enzymes involved in the muscular metabolism.
Topics: Adenosine Triphosphate; Anaerobiosis; Animals; Arginine; Bivalvia; Hempa; Hydrolysis; In Vitro Techniques; Kinetics; Magnetic Resonance Spectroscopy; Muscles; Organophosphorus Compounds; Phosphorus; Seasons; Temperature
PubMed: 3699028
DOI: 10.1111/j.1432-1033.1986.tb09623.x -
Proceedings of the National Academy of... Apr 2004It is found that the addition of hexamethylphosphoramide to the solution of an alkyne, Et(2)Zn, and (S)-1,1'-bi-2-naphthol in methylene chloride allows the generation of...
It is found that the addition of hexamethylphosphoramide to the solution of an alkyne, Et(2)Zn, and (S)-1,1'-bi-2-naphthol in methylene chloride allows the generation of an alkynylzinc at room temperature and shows highly enantioselective additions to aldehydes. The mild condition for the formation of the alkynylzinc reagent enables the use of functional alkynes in this asymmetric reaction with excellent enantioselectivity. It avoids the reflux of the toluene solutions of the alkynes and Et(2)Zn as previously reported.
Topics: Alkynes; Benzaldehydes; Hempa; Naphthols; Organometallic Compounds; Stereoisomerism; Zinc
PubMed: 15026570
DOI: 10.1073/pnas.0307136101 -
The American Journal of Pathology Jan 1982Rats exposed by inhalation to hexamethylphosphoramide (HMPA) at concentrations of 50, 100, 400, and 4000 parts per billion (ppb) for 6-24 months revealed nasal tumors...
Rats exposed by inhalation to hexamethylphosphoramide (HMPA) at concentrations of 50, 100, 400, and 4000 parts per billion (ppb) for 6-24 months revealed nasal tumors and squamous metaplasia with inflammation in the nasal epithelium, but no changes were observed at 10 ppb. The ciliated cells were most susceptible to HMPA, showing degenerative changes, with abnormal cilia and extensive deciliation. The desquamated nasal epithelium was repaired initially by undifferentiated mucus or microvillous cuboidal cells, and subsequently the lining cells were replaced with squamous cells migrating upward from the basal layer. In the early stage of squamous metaplasia, thickened nasal epithelium revealed indifferent cells, undifferentiated glandular cells, transitional cells from glandular to squamous cells, poorly differentiated squamous cells, and intermediate cells showing features of glandula and squamous differentiation. Subsequently, the undifferentiated glandular cells were replaced mainly with the squamous or intermediate cells. the undifferentiated glandular cells appeared to be biphasic reserve cells capable of differentiating to glandular or squamous cells. The intermediate cells appeared to be derived from the undifferentiated glandular cells and converted into keratinizing squamous cells. Numerous secretory vesicles and mucus droplets were observed in the squamous cells adjacent to the keratinized area and keratin plates.
Topics: Adenocarcinoma; Animals; Carcinoma, Squamous Cell; Female; Hempa; Male; Metaplasia; Microscopy, Electron; Nasal Mucosa; Nose Neoplasms; Organophosphorus Compounds; Rats
PubMed: 7055213
DOI: No ID Found -
Genetics Feb 1995The nature of DNA sequence changes induced by the cross-linking agent hexamethylphosphoramide (HMPA) within and in the vicinity of the vermilion locus of Drosophila...
The nature of DNA sequence changes induced by the cross-linking agent hexamethylphosphoramide (HMPA) within and in the vicinity of the vermilion locus of Drosophila melanogaster that produce a vermilion mutant phenotype was analyzed after exposure of postmeiotic male germ cells. Mutagenized males were mated to either females wild-type (exr+) for nucleotide excision repair (NER) or to females having a deficiency (exr-) for NER. Rearrangements, mostly deletions, represented by far the most frequent type of mutational events induced by HMPA that are detected as vermilion mutations. In the exr+ group, all but one (a double substitution) of 21 mutants characterized were large sequence changes: we found 5 intra-locus deletions, 3 intra-locus deletions associated with insertions and 12 multi-locus deletions. When taken together, deletions and deletion/insertion mutations represent 96% of the HMPA-induced DNA modifications obtained under proficient repair conditions. Of the 10 mutants obtained from crosses with exr- females, 6 intra-locus and 2 multi-locus deletions were found, as opposed to just 1 point mutation and 1 double substitution. The "hypomutability effect" observed with exr- genotypes in relation to the wild type seems to be caused by a decrease in the frequency of multi-locus deletions in the former group. The results suggest that the NER system is involved in the generation of multi-locus deletions, whereas intra-locus deletions appear to be formed through a postreplication slipped-misrepair pathway. It is concluded that an eukaryotic in vivo system with no limitations for the recovery of multi-locus deletions, such as vermilion, should be used for the analysis of DNA damage induced by cross-linking agents.
Topics: Animals; Base Sequence; Cross-Linking Reagents; Crosses, Genetic; DNA Adducts; DNA Damage; DNA Mutational Analysis; DNA Repair; Drosophila melanogaster; Female; Genes, Lethal; Genes, Recessive; Hempa; Male; Molecular Sequence Data; Mutagenesis; Mutation; Sequence Deletion; Spermatozoa
PubMed: 7713422
DOI: 10.1093/genetics/139.2.649 -
European Journal of Biochemistry Dec 1984The beta-D-galactoside transport protein (y-gene product) of Escherichia coli, strain T 206, was solubilized in 85-95% yield using the organic solvents...
The beta-D-galactoside transport protein (y-gene product) of Escherichia coli, strain T 206, was solubilized in 85-95% yield using the organic solvents hexamethylphosphoric triamide at pH 7.5 or butan-1-ol at pH 4.2. The transport protein obtained with the former solvent could be incorporated into a defined lipid/protein aggregate of density 1.12 g/ml, but no beta-D-galactoside binding was restored. Diacylglycerol kinase regained activity in the same lipid/protein aggregates. In control experiments, liposomes formed from hexamethylphosphoric triamide were found to be active in the valinomycin-mediated uptake of Rb+ ions. beta-D-Galactoside binding (3.6-5.7 nmol/mg protein) as well as diacylglycerol kinase activity [7 nmol min-1 (mg protein)-1] was reconstituted into proteoliposomes from butan-1-ol solution by adaptation of a published procedure [Wright, J. K. et al. (1982) Eur. J. Biochem. 124, 545-552]. A microparticulate nature of the butan-1-ol-solubilized transport protein could be excluded by gel permeation chromatography on a newly synthesized matrix, hydroxypropyl-Sephacryl S-300.
Topics: Butanols; Cell-Free System; Escherichia coli; Escherichia coli Proteins; Galactosides; Glycosides; Hempa; Liposomes; Membrane Proteins; Membrane Transport Proteins; Monosaccharide Transport Proteins; Solubility; Solvents; Symporters
PubMed: 6389133
DOI: 10.1111/j.1432-1033.1984.tb08567.x -
Hereditas 1971
Topics: Animals; Azirines; Cells, Cultured; Chromosome Aberrations; Chromosomes; Cricetinae; Hempa; Lung; Mitosis; Plants; Structure-Activity Relationship; Thymidine; Time Factors; Triethylenephosphoramide; Tritium
PubMed: 4142011
DOI: 10.1111/j.1601-5223.1971.tb02401.x -
FEBS Letters Nov 1978
Topics: Bacterial Proteins; Cations, Divalent; Coliphages; Hempa; Methods; Molecular Weight; Organophosphorus Compounds; Receptors, Virus; Solubility; Solvents
PubMed: 720588
DOI: 10.1016/0014-5793(78)80062-3 -
FEBS Letters Jul 1981
Topics: Cell Membrane; Diacylglycerol Kinase; Escherichia coli; Hempa; Indicators and Reagents; Organophosphorus Compounds; Phosphotransferases; Solubility
PubMed: 6269883
DOI: 10.1016/0014-5793(81)80188-3 -
Hereditas 1971
Topics: Alkylation; Ascomycota; Azirines; Coliphages; Escherichia coli; Hempa; Lysogeny; Mutagens; Mutation; Structure-Activity Relationship; Triethylenephosphoramide
PubMed: 4142010
DOI: 10.1111/j.1601-5223.1971.tb02400.x