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See detailConformational analysis of peptide substrates and inhibitors of the Zn2+ G and serine R61 D-alanyl-D-alanine peptidases
De Coen, Jean-Louis; Lamotte, Josette ULg; Ghuysen, Jean-Marie ULg et al

in European Journal of Biochemistry (1981), 121(1), 221-232

The tripeptide Nα,Nɛ-diacetyl-l-lysyl-d-alanyl-d-alanine (Ac2- l-LLys1-dAIa2-dAIa3), which is the standard substrate of the Zn2+ G and serine R61 d-alanyl-d-alanine peptidases, and several ldd tripeptide ... [more ▼]

The tripeptide Nα,Nɛ-diacetyl-l-lysyl-d-alanyl-d-alanine (Ac2- l-LLys1-dAIa2-dAIa3), which is the standard substrate of the Zn2+ G and serine R61 d-alanyl-d-alanine peptidases, and several ldd tripeptide analogues where the size and/or the electrical charge of the side chains at position 1, 2 or 3 have been modified (alterations affecting more than one position at the same time were not investigated) have been submitted to conformational analyses based on both short-range and long-range interactions. Among the many backbone conformers of minimal energy of the øii space that have been characterized, four types of conformers are the most probable ones. Depending on the peptides, these conformers may have varying relative probability P values so that the leader conformer is not always the same, but, in all cases, the sum of their P values is 90% or more. With the Gly1, Gly2 or Gly3 analogues (which encompass a larger conformational space), the above ∑P values are still as high as 35–50%. All the above tripeptides bind to the serine d-alanyl-d-alanine peptidase and with the exception of the Gly3 and Gly2 analogues, to the Zn2+d-alanyl-d-alanine peptidase with virtually the same efficacy, at least within a range of variation of the Km values for the substrates or the Ki values for the inhibitors, which is less than one order of magnitude. Structural variations at position 1, 2 or 3 in the peptides that are compatible with efficient binding are not necessarily compatible with substrate activity, thus converting the modified peptides into competitive inhibitors. In particular, substrate activity requires a long side chain at position 1 in the peptides. Conformational analyses of Ac2-lLys-dAla-dAla show that the main backbone has a tendency to adopt a ring-like shape from which the lLYS side chain protrudes as an extended structure. This latter structure forms with the C-terminal d-alanyl-d-alanine an angle varying between 120° and 180° (depending on the conformers) so that its N-terminal acetyl group is about 1–1.5 nm apart from the scissile amide bond. High turnover numbers (at enzyme saturation) also require a dAla at position 2 with both d-alanyl-d-alanine peptidases and at position 3 in the case of the serine d-alanyl-d-alanine peptidase. Finally, all the conformers of the lAla2 and lAla3 analogues of Ac2-lLys-dAla-dAla fall outside the backbone conformational space that comprises the φiφi angles exhibited by the four types of conformers of the ldd tripeptides. The lAla2 and lAla3 tripeptide analogues do not bind to the serine d-alanyl-d-alanine peptidase (at least at a 10 mM concentration) but they behave as noncompetitive inhibitors of the Zn2+d-alanyl-d-alanine peptidase. [less ▲]

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See detailInternational Directory of Amateur Astronomical Societies - IDAAS 1982
Heck, Andre; Manfroid, Jean ULg

in International Directory of Amateur Astronomical Societies - IDAAS 1982 (1981), iv + 304pp. (1981)

Not Available

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See detailLe dosage des apolipoproteines
MELIN, Pierrette ULg

Scientific conference (1981, November 26)

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See detailLe nouveau né de mère diabétique
Battisti, Oreste ULg; Bachy, A.; Gérard, P.

Conference given outside the academic context (1981)

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See detailFurther spectroscopic observations of 25 quasi-stellar objects
Surdej, Jean ULg; Swings, Jean-Pierre ULg

in Astronomy and Astrophysics. Supplement Series (1981), 46

Spectroscopic observations are reported for 25 quasars suspected of having line profiles which are indicative of mass outflow from the central quasar. The quasars were selected on the basis of optical ... [more ▼]

Spectroscopic observations are reported for 25 quasars suspected of having line profiles which are indicative of mass outflow from the central quasar. The quasars were selected on the basis of optical variability and/or the presence of P Cygni spectral profiles, and large emission redshift, and observed on widened spectrograms obtained at the Cassegrain focus of the ESO 3.6-m telescope at La Silla during December 1977 and July 1978. Observations confirm the previously detected emission and absorption redshifts for most of the quasars, and reveal previously undetected lines and absorption redshifts in a few cases. [less ▲]

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See detailIntérêt de l'électrodermographie en psychopathologie
Gernay, Pierre; Mormont, Christian ULg

in Psychologie Médicale (1981), 13(12), 1939-1941

Tested 37 former female prisoners of war to determine if a correlation exists between the level of electrodermal activity and depression/anxiety. Four tests were administered, including some word ... [more ▼]

Tested 37 former female prisoners of war to determine if a correlation exists between the level of electrodermal activity and depression/anxiety. Four tests were administered, including some word-recognition exercises and a measure of Ss' response time. Although the results were not sufficient to warrant a diagnosis, some significant correlations of at least .05 were recognized. It is suggested that electrodermal assessment should continue to be a part of the diagnostic process. [less ▲]

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See detailModification of Chloroplast Gene Transmission in Somatic Fusion Products and Vegetative Zygotes of Chlamydomonas Reinhardi by 5-Fluorodeoxyuridine
Matagne, René-Fernand ULg; Hermesse, Marie-Paule

in Genetics (1981), 99(3-4), 371-381

Sexual crosses and somatic fusions were performed between complementing wall-less arg(-) mutant strains bearing chloroplast markers for resistance to antibiotics. The mode of chloroplast allele ... [more ▼]

Sexual crosses and somatic fusions were performed between complementing wall-less arg(-) mutant strains bearing chloroplast markers for resistance to antibiotics. The mode of chloroplast allele transmission was investigated in the diploid colonies developed from both vegetative zygotes and fusion products. Before mating or fusion, one or both of the parental strains were grown for 4 or 8 days on agar containing 5-fluorodeoxyuridine (FUdR, 0.1 to 1.0 mm), which selectively reduces the amount of chloroplast DNA in Chlamydomonas. When one parent was pregrown on FUdR, the frequency of vegetative zygotes transmitting chloroplast alleles of both parents (biparental or BP zygotes) decreased, the reduction being more drastic when the mt(-) parent was treated. Transmission was mainly uniparental maternal (UPm) or paternal (UPp) depending on whether the mt(-) or the mt(+) parent was pregrown for 8 days in the presence of 1.0 mm FUdR. Treatment of both parents led to a strong maternal transmission. In the experiments involving somatic fusion between parent 1 and parent 2 (same or opposite mt), the ratio UP(1)/UP(2), which was approximately equal to 1 in the control, decreased or increased according to whether the cells of parent 1 or 2 were pregrown on FUdR. In parallel, the frequency of BP fusion products always decreased. When both parental strains were treated with FUdR, the frequency of BP fusion products also decreased and the ratio UP(1)/UP(2) was roughly equal to 1. The effect of FUdR can be interpreted in terms of reduction of the input frequencies of parental chloroplast genomes at the time of gametic or somatic cell fusion, the bias in favor of the maternal parent being operational only in sexual crosses. [less ▲]

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See detailOntogenic development of steroid 16 alpha-hydroxylase as a tool for the study of the multiplicity of cytochrome P-450.
Pasleau, Françoise ULg; Kolodzici, Claudine; Kremers, Pierre ULg et al

in European Journal of Biochemistry (1981), 120

1. Activities of progesterone, testosterone, pregnenolone and dehydroepiandrosterone 16 alpha-hydroxylase are undetectable in the fetal rat liver. During the neonatal period, the four enzymic activities ... [more ▼]

1. Activities of progesterone, testosterone, pregnenolone and dehydroepiandrosterone 16 alpha-hydroxylase are undetectable in the fetal rat liver. During the neonatal period, the four enzymic activities increase in parallel to the concentration of cytochrome P-450. Until puberty, they develop similarly in male and female rat livers. From the 40th to the 55th day, the four steroid 16 alpha-hydroxylase activities increase rapidly in the male rat liver. The sexual differentiation of the steroid 16 alpha-hydroxylation observed in adult male and female rats takes place around the 55th day. 2. In the adult rat liver, steroid 16 alpha-hydroxylase is supported by two forms of cytochrome P-450 (form I and form II), which differ in their relative affinities for the various steroid substrates, and by their relative proportions in male and female rat livers. These two forms of cytochrome P-450 are also present in the young male and female rat livers, but are roughly equal in proportion. The transition from the immature to the adult repartition of the two forms occurs during puberty and is correlated with the sexual differentiation of the steroid 16 alpha-hydroxylase activities. 3. During the critical phases of the rat ontogenic development, the in vitro interactions between benzo[a]pyrene and steroids were compared at the level of two rat liver monooxygenases: steroid 16 alpha-hydroxylase and aryl hydrocarbon hydroxylase. (a) In the immature male and female rat livers, progesterone 16 alpha-hydroxylase, and to a lesser extent, pregnenolone 16 alpha-hydroxylase are inhibited by benzo[a]pyrene. Progesterone 16 alpha-hydroxylase is also inhibited by metyrapone. (b) In the young rat, aryl hydrocarbon hydroxylase cannot be inhibited by steroids and appears to be supported by a single form of cytochrome P-450. The transition from the immature to the adult situation occurs around the 40th day. [less ▲]

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See detailApplications des techniques spectrométriques dans le domaine des produits naturels...
Angenot, Luc ULg; Coune, Claude

Scientific conference (1981, October 19)

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See detailInfections respiratoires et pathologie de la clairance muco-ciliaire
Castronovo, Vincenzo ULg; Simar, L.; Geubelle, F.

in Revue Médicale de Liège (1981), 36(20), 760-6

L'ultrastructure et le fonctionnement des cils de la muqueuse respiratoire sont actuellement mieux connus. Il est donc possible de diagnostiquer les dyskinésies ciliaires qui peuvent expliquer l ... [more ▼]

L'ultrastructure et le fonctionnement des cils de la muqueuse respiratoire sont actuellement mieux connus. Il est donc possible de diagnostiquer les dyskinésies ciliaires qui peuvent expliquer l'inefficacité de "l'escalator mucociliaire". [less ▲]

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See detailContraintes budgétaires et avenir de l'Université
Betz, Emile-Hippolyte ULg

Speech (1981)

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See detailA photoelectric investigation of light variability in Ap stars
Hensberge, H.; Deridder, G.; Doom, C. et al

in Astronomy and Astrophysics. Supplement Series (1981), 46

A study of the light variability of a number of peculiar A stars, mainly in Stromgren colors u and v and in peculiarity index Delta-a, leads to the proposal of the following light variability periods: (1 ... [more ▼]

A study of the light variability of a number of peculiar A stars, mainly in Stromgren colors u and v and in peculiarity index Delta-a, leads to the proposal of the following light variability periods: (1) HD 5601, 1.11 days; (2) HD 19712, 2.19 days; (3) HD 30849, 15.86 days; (4) HD 38823, 8.64 days; (5) HD 53116, 11.98 or 18.10 days; (6) HD 56022, 0.92 days; and (7) HD 81009, 33.97 days. In addition, evidence is given for variability of HD 94660 on a time scale on the order of months or years, and it is shown that the rotation period proposed by Borra and Landstreet (1980) for HD 25267 is not supported by the light variations observed. The character of Delta-a variability is discussed. [less ▲]

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See detailVariations Photometriques et Periode de HR 2971 (note Rectificative a l'IBVS no 2004)
Manfroid, Jean ULg; Renson, Pierre ULg

in Information Bulletin on Variable Stars (1981), 2032

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See detailEvaluation of Housing Heat Gains due to Metabolism, Artificial Lighting, Appliances and Domestic Hot Water User
Hauglustaine, Jean-Marie ULg

(1981, October)

The evaluation of sensible heat gains due to house occupancy is possible by taking into account the family occupancy pattern, the main source of information that gives up: - the rooms occupied by any ... [more ▼]

The evaluation of sensible heat gains due to house occupancy is possible by taking into account the family occupancy pattern, the main source of information that gives up: - the rooms occupied by any member of the family (with the activity realized at each moment of the day) ; - the use of domestic hot water ; - the use of appliances. Two household occupancy patterns are chose, corresponding to most common families. The calculation of incidental heat gains due to metabolism takes into account radiative and convective exchange from human body to its ambiance. The activities realized along the day are known, and so on the illumination levels. The necessary artificial lighting electrical power and the periods of switching-on are determined with the help of simplified methods. Heat losses wasted at production, storage, distribution and use of domestic hot water are situated. Internal heat gains lost by domestic appliances (gas or electric cooker, refrigerator, deep-freezer…) are estimated taking into account characteristics (volume, size) of appliance and for a typical use. Then internal heat gains due to human occupancy become possible to evaluate hour by hour and room by room, which is interesting for estimation of peak overheating temperature or decrement of consign temperature. [less ▲]

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See detailUterine motility in cattle prior to and post parturition (preliminary results)
Hanzen, Christian ULg

in Karg, H.; Schallenberger, E. (Eds.) Factors influencing fertility in the cow. (1981, September 30)

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See detailEvaluation of risk using serial laboratory data in acute myocardial infarction
Chapelle, Jean-Paul ULg; Albert, Adelin ULg; Heusghem, C. et al

Conference (1981, September)

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See detailQuantitative aspects of serum myoglobin changes in acute myocardial infarction
Chapelle, Jean-Paul ULg; Albert, Adelin ULg; Smeets, J. P. et al

Poster (1981, September)

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