bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enzymatic Properties and Inhibition by Single‐Stranded Autonomously Replicating Sequences of Adenylosuccinate Synthase from Saccharomyces cerevisiae
Authors: Gallert Karl‐Christian , Ohanjan Tanja , Daignan‐Fornier Bertrand , Lottspeich Friedrich , Krauss Gerhard 
Published: July 2004

Adenylosuccinate synthase (ASS) from Saccharomyces cerevisiae has been shown to bind specifically to the T‐rich side of the autonomously replicating sequence (ARS) core consensus sequence [Zeidler, R., Hobert, O., Johannes, L., Faulhammer, H. & Krauss, G. (1993) J. Biol. Chem. 268, 20191–20197]. We have cloned and sequenced the gene for ASS and have studied in detail the enzymatic properties and DNA‐binding activity of ASS. The deduced amino acid sequence of the yeast ASS is highly similar to the same enzymes from other sources from which it is however distinguished by its more basic nature.We show that the enzymatic activity of ASS is inhibited in a highly specific manner by the binding of a 44‐base DNA oligonucleotide carrying the ARS core consensus sequence. Other nucleic acids, rNTP and dNTP are not able to mimic the specific inhibitory effect. Single‐base substitutions in the ARS core sequence lead to a tenfold reduction in inhibition. The inhibition data corroborate the earlier report on the DNA‐binding specificity of this enzyme. The homologous enzymes from Escherichia coli and Dictyostelium discoideum do not show specific binding to single‐stranded ARS sequences and their enzymatic activity is not influenced by the presence of a 44‐base DNA oligonucleotide carrying the ARS core consensus sequence.Treatment of ASS with alkaline phosphatase leads to a loss of DNA binding and to a loss of the inhibition by DNA of the enzymatic activity which suggests that the DNA‐binding activity but not the enzymatic activity may be regulated by the phosphorylation status of the protein.
Phenylalanyl‐tRNA Synthetase from Yeast and Its Discrimination of 19 Amino Acids in Aminoacylation of tRNAPhe‐C‐C‐A and tRNAPhe‐C‐C‐A(3′NH2)
Authors: Freist Wolfgang , Sternbach Hans , Cramer Friedrich 
Published: July 2004

For discrimination between phenylalanine and 18 other naturally occurring non‐cognate amino acids by the class II aminoacyl‐tRNA synthetase specific for phenylalanine, discrimination factors, D, of 190–6300 have been determined from kcat and Km values. Generally, phenylalanyl‐tRNA synthetase is more specific than the class II enzymes specific for Lys and Thr, but works with lower accuracy than the class I enzymes specific for IIe, Tyr, and Arg.In aminoacylation of tRNA Phe‐C‐C‐A(3′NH2) discrimination factors D1 vary between 80–1610. Pre‐transfer proof‐reading factors II1 are in the range 2.3–74, post‐transfer proof‐reading factors II2 in the range 1.0–4.6, showing that pre‐transfer proof‐reading is the main correction step, post‐transfer proof‐reading is less effective or negligible.Initial discrimination factors (I1 and I2) caused by differences in Gibbs free energies of binding between phenylalanine and non‐cognate amino acids have been calculated assuming a two‐step binding process. Factors I1 can be related to hydrophobic‐interaction forces depending on accessible surface areas of the amino acids, factors I2 scatter about a low mean value and do not show any relation to amino acid structures or surfaces, indicating less checking of amino acid side chains in the putative second binding step.
Structural Analysis of the O‐Antigenic Polysaccharide from the Enteropathogenic Escherichia coli O125
Authors: Kjellberg Alexandra , Urbina Felipe , Weintraub Andrej , Widmalm Göran 
Published: July 2004

The structure of the polysaccharide part of the lipopolysaccharide obtained from the enteropathogenic Escherichia coli O125 has been investigated. Methylation analysis, 1H‐NMR spectroscopy and 13C‐NMR spectroscopy revealed that the polysaccharide is composed of repeating hexasaccharide units. Smith degradation of the native O‐polysaccharide resulted in a polysaccharide with four sugar residues in the repeating unit. Information on the sequence of the native O‐polysaccharide and the Smith‐degraded product was obtained by two‐dimensional‐NMR techniques, namely heteronuclear‐mutiple‐bond‐connectivity and NOESY experiments. The structure of the repeating unit of the O‐polysaccharide of E. coli strain O125, which has two adjacent branch‐point residues, is
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Lipid‐Binding Properties of Synthetic Peptide Fragments of Human Apolipoprotein A‐II
Authors: Benetollo Claire , Lambert Gilles , Talussot Corinne , Vanloo Berlinda , Van Cauteren Tom , Rouy Didier , Dubois Hervé , Baert Johan , Kalopissis Athina , Denèfle Patrice , Chambaz Jean , Brasseur Robert , Rosseneu Maryvonne 
Published: July 2004

Human apolipoprotein A‐II (apo A‐II) consists of three potential amphipathic helices of 17 residues each, which contribute to the lipid‐binding properties of this apolipoprotein. The conformation and lipid‐binding properties of these peptides, either as single‐helix or as two‐helix peptides, were investigated by turbidity, fluorescence, electron‐microscopy and circular‐dichroism measurements, and are compared in this article. The lipid affinity of shorter C‐terminal segments of apo A‐II was compared with those of the single‐helix or two‐helix peptides, to define the minimal peptide length required for stable complex formation. The properties of the apo‐A‐II‐(13–48)‐peptide were further compared with those of the same segment after deletion of the Ser31 and Pro32 residues, because the deleted apo‐A‐II‐(13–30)‐(33–48)‐peptide, is predicted to form a long uninterrupted helix.The single helices of apo A‐II could not form stable complexes with phospholipids, and the helix‐turn‐helix segment spanning residues 13–48 was not active either. The apo‐A‐II‐(37–77)‐peptide and the apo‐A‐II‐(40–73)‐peptide could form complexes with lipids, which appear as discoidal particles by negative‐staining electron microscopy. The shortest C‐terminal domain of apo A‐II, able to associate with lipids to form stable complexes was the apo‐A‐II‐(40–73)‐peptide, which consisted of the C‐terminal helix, a β‐turn and part of the preceding helix. The shorter apo‐A‐II‐(49–77)‐peptide, and the helical apo‐A‐II‐(13–30)‐(33–48)‐peptide, could also associate with phospholipids. The complexes formed were, however, less stable, as they dissociated outside the transition temperature range of the phospholipid.These data suggest that the C‐terminal pair of helices of apo A‐II, which is the most hydrophobic pair, is responsible for the lipid‐binding properties of the entire protein. The N‐terminal pair of helices of apo A‐II at residues 13–48 does not associate tightly with lipids. The degree of internal similarity and the cooperativity between the helical segments of apo A‐II is thus less pronounced than in apo A‐I or apo A‐IV. The N‐terminal and C‐terminal domains of apo A‐II appear to behave as two distinct entities with regard to lipid‐protein association.
Further Characterization of the Peroxisomal 3‐Hydroxyacyl‐Coa Dehydrogenases from Rat Liver
Authors: Dieuaide‐Noubhani Martine , Novikov Dmitry , Baumgart Eveline , Vanhooren Johannes C. T. , Fransen Marc , Goethals Marc , Vandekerckhove Joël , Van Veldhoven Paul P. , Mannaerts Guy P. 
Published: July 2004

Recently, we purified five 3‐hydroxyacyl‐CoA dehydrogenases from isolated rat liver peroxisomal fractions. The enzymes were designated I–V according to their order of elution from the first column used in the purification procedure. Determination of the substrate (l‐ or d‐hydroxyacyl‐CoA) stereospecificity and (de)hydratase measurements with the different 3‐hydroxyacyl‐COA stereoisomers of straight‐chain fatty acids and the bile acid intermediate trihydroxycoprostanic acid, immunoblotting analysis with antibodies raised against the different enzymes and peptide sequencing, all performed on enzymes I–V and molecular cloning of enzyme III revealed the following picture.Rat liver peroxisomes contain two multifunctional β‐oxidation proteins: (a) multifunctional protein 1 (the classical multifunctional protein; MFP‐1) displaying 2‐enoyl‐CoA hydratase, l–3‐hydroxyacyl‐CoA dehydrogenase and Δ3, Δ2‐enoyl‐CoA isomerase activity (enzyme IV) and (b) multifunctional protein 2 (MFP‐2) displaying 2‐enoyl‐CoA hydratase and d‐3‐hydroxyacyl‐CoA dehydrogenase activity (enzyme III).Because of their substrate stereospecificity and because of the stereochemical configuration of the naturally occurring β‐oxidation intermediates, MFP‐1 and MFP‐2 appear to be involved in the β‐oxidation of fatty acids and bile acids intermediates, respectively.The deduced amino acid sequence of the cloned MFP‐2 cDNA is highly similar to that of the recently described porcine endometrial estradiol 17β‐dehydrogenase [Leenders, F., Adamski, J., Husen, B., Thole, H. H. & Jungblut, P. W. (1994) Eur. J. Biochem. 222, 221–227]. In agreement, MFP‐2 also displayed estradiol 17β‐dehydrogenase activity, indicating that MFP‐2 and the steroid dehydrogenase are identical enzymes.MFP‐2 is partially cleaved, most probably in vivo, in a estradiol 17β‐dehydrogenasel/d‐3‐hydroxyacyl‐CoA dehydrogenase that forms a dimeric complex (enzyme I) and a hydratase. The physiological significance of enzyme I in bile acid synthesis (and steroid metabolism) remains to be determined. MFP‐1 (enzyme IV) is artefactually cleaved during purification giving rise to 3‐hydroxyacyl‐CoA dehydrogenase V. 3‐Hydroxyacyl‐CoA dehydrogenase II is a mitochondrial contaminant similar to porcine and murine mitochondrial 3‐hydroxyacyl‐CoA dehydrogenase.
Explicit Constants for the Dextran‐Sulfate‐Mediated Activation and Autoactivation of Purified Human Factor XII (Hageman Factor)
Authors: Loiseau Céline , Randriamahazaka Hyacinthe N. , Nigretto Jean‐Maxime 
Published: July 2004

The autoactivation kinetics of purified factor XII (FXII) in the presence of dextran sulfate of 500 000 Da was reexamined assuming the existence of two preceding activation steps. Kinetics were numerically simulated by using rate and equilibrium constants related to surface‐bound species. Relevant feature parameters related to the polymer (number of binding sites and concentration, dissociation constant of FXII from the surface) and the zymogen (concentration, Michaelis‐Menten constant of the autoactivation reaction, catalytic rate constant) were accordingly introduced in the mechanisms. Depending on the rate‐limiting step, i.e. whether the polymer or FXII predominates, numerical simulation analysis led to obtain for the observed autoactivation rate constant (kobs) two explicit expressions which included the contributing variables.One of the two proposed models was in good accordance with the experimental data obtained in this study and with others published previously. We were able to estimate the mean number of the FXII‐activating sites supported by the polymer chains (220) and the equilibrium dissociation constant of FXII from the surface (1 μM). Further treatment led us to determine surface‐concentration‐independant constants (Km= 2510 nM and kcat= 0.01 s‐1), as well as the rate constant (k1= 1.6×10‐4 s‐1) of the postulated first‐order activation rate aimed at explaining the formation of the first trace amounts of FXIIa via an intramolecular mechanism. Overall, the treatment applied to the dextran sulfate case offers a quantitative tool by which data determined in the presence of other activating materials can be rationalized.
Primary Structure and Characterization of an Exopolygalacturonase from Aspergillus Tubingensis
Authors: Kester Harry C. M. , Someren Margo A. Kusters‐Van , Müller Yvonne , Visser Jaap 
Published: July 2004

From the culture fluid of the hyphal fungus Aspergillus tubingensis, an exopolygalacturonase with a molecular mass of 78 kDa, an isoelectric point in the pH‐range 3.7–4.4 and a pH optimum of 4.2 was purified. The enzyme has been characterized as an exopolygalacturonase [poly(1,4‐α‐d‐galacturonide)galacturonohydrolase] that cleaves monomer units from the non‐reducing end of the substrate molecule. K
m and Vmax for polygalacturonic acid hydrolysis were 3.2 mg ml−1 and 3.1 mg ml−1 and 255 U mg I and 262 U mg−1 for the wild‐type and recombinant enzymes, respectively. The kinetic data of exopolygalacturonase on oligogalacturonates of different degree of polymerization (2–7) were interpreted in terms of a subsite model to obtain more insight into catalysis and substrate binding. On oligogalacturonates of different degrees of polymerization (2–7), the Michaelis constant (Km) decreased with increasing chain length (n). The Vmax value increased with chain length up to n= 4, then reached a plateau value. The enzyme was competitively inhibited by galacturonic acid (Ki= 0.3 mM) as well as by reduced digalacturonate (Ki= 0.4 mM).The exopolygalacturonase gene (pgaX) was cloned by reverse genetics and shows only 13% overall amino acid sequence identity with A. niger endopolygalacturonases. The exopolygalacturonase is most related to plant polygalacturonases. Only four small stretches of amino acids are conserved between all known endogalacturonases and exopolygalacturonases. Expression of the pgaX gene is inducible with galacturonic acid and is subject to catabolite repression. A fusion between the promoter of the A. niger glycolytic gene encoding pyruvate kinase and the pgaX‐coding region was used to achieve high level production of exopolygalacturonase under conditions where no endopolygalacturonases were produced.
Response of the whitespotted sawyer beetle, Monochamus s. scutellatus, and associated woodborers to pheromones of some Ips and Dendroctonus bark beetles
Authors: de Groot P. , Nott R. W. 
Published: July 2004

Abstract:The response of whitespotted sawyer beetle, Monochamus s. scutellatus, to pheromones of the bark beetles, Dendroctonus rufipennis, Ips pini, Ips perturbatus and Ips latidens, and α‐pinene was investigated with field‐trapping experiments. Traps baited with ipsenol caught significantly more M. s. scutellatus than unbaited traps, whereas the other compounds (ipsdienol, ipsdienol plus lanierone, ipsdienol plus cis‐verbenol or frontalin) did not. Combining α‐pinene with ipsdienol, ipsdienol plus lanierone, ipsdienol plus cis‐verbenol or with frontalin did not increase captures of M. s. scutellatus above those of α‐pinene alone, whereas the combination of α‐pinene with ipsenol did. When α‐pinene was combined with ipsdienol or frontalin, trap captures of Monochamus mutator were significantly higher than unbaited traps or traps baited with frontalin but were not higher than traps baited with α‐pinene. The combination of ipsenol and α‐pinene was significantly more attractive to Monochamus notatus than unbaited traps; however, traps containing either ipsenol or α‐pinene were as attractive as the combination. None of the species of Buprestidae (Buprestis maculativentris and Chalcophora virginiensis) responded significantly to any of the treatments.
Temperature‐dependent development and immature survival of an aphidophagous ladybeetle, Propylea dissecta (Mulsant)
Authors: Omkar  , Pervez A. 
Published: July 2004

Abstract:Development and survival of the immature stages of an aphidophagous ladybeetle, Propylea dissecta (Mulsant) was investigated at five constant temperatures, viz. 20, 25, 27, 30 and 35°C, using Aphis gossypii Glover as prey. Developmental period of all the life stages were significantly affected with change in constant temperature and developmental rate increased with increase in temperature. Theoretical lower thermal threshold for complete development and thermal constant was 10.39°C and 465.11 Day‐degrees, respectively. Of the various life stages, first instar larvae were most susceptible to mortality at temperatures between 20 and 30°C, whilst pre‐pupae suffered least mortality. Egg‐mortality was maximum at 35°C. Female biased sex ratios were obtained at all five temperatures tested with higher proportion of females at the extremes of temperature, thus suggesting that females are more thermal‐tolerant. Lowest mortality of immature stages with maximum larval survival and adult emergence was recorded at 27°C, while reverse was the case at 35°C. Thus, 27°C may be considered best for the laboratory rearing of P. dissecta.
Levels of cardiac knowledge and cardiopulmonary resuscitation training among older people in Queensland
Authors: Johnston Trish C , Clark Michele J , Dingle Genevieve A , Sanders Emma L 
Published: July 2004

Objectives: The current study was conducted to determine levels of cardiac knowledge and cardiopulmonary resuscitation (CPR) training in older people in Queensland, Australia. Methods: A telephone survey of 4490 Queensland adults examined respondents’ knowledge of coronary heart disease (CHD) risk factors, knowledge of heart attack symptoms, knowledge of the local emergency telephone number, as well as respondents’ rates and recency of training in CPR. Results: Older participants, aged 60 years and over, were approximately one and a half times more likely than the 30–39 year‐old reference group to have limited knowledge of heart disease risk factors (OR = 1.53), and low knowledge of heart attack symptoms (OR = 1.60). Knowledge of the local emergency telephone number also decreased with age. Older participants had significantly lower rates of training in CPR, with almost three quarters (71.7%) reporting that they had never been trained. Older people who had completed CPR training were significantly less likely to have done so recently. Conclusions: Cardiac knowledge levels and CPR training rates in older Queensland persons were lower than those found in the younger population.
Investigation of automatic teller machine banking in a sample of older adults
Authors: Darch Ulrike , Caltabiano Nerina J 
Published: July 2004

Objective:To explore the relationship between demographic, user‐situational, attitudinal variables and automatic teller machine (ATM) use in an Australian sample of older adults.Methods:Volunteers aged 60 years and over conducting their own banking filled in a self‐administered questionnaire which assessed respondents’ banking practices, attitudes towards ATMs, and demographics. Mann–Whitney U‐tests and chi‐squared tests were computed to explore group differences, and a logistic regression analysis was conducted to assess the predictive value of identified variables.Results:The sample comprised 139 respondents of which 44.6% were ATM users and 55.4% were non‐users. Group differences were found in regard to age, education, user situational and attitudinal variables. From the logistic regression, technology, perceived control and perceived user comfort were found to have an independent significant effect on ATM usage.Conclusion:The results suggest that while age, education, attitudes and user‐situational variables are related to ATM use, only technology experience, perceived user comfort and control are determinants of ATM use among this population.
Population Pharmacokinetics of Daptomycin
Authors: Dvorchik Barry , Arbeit Robert D. , Chung Julia , Liu Susan , Knebel William , Kastrissios Helen 
Published: July 2004

ABSTRACT

Data from subjects in nine phase 1 (
n
= 153) and six phase 2/3 (
n
= 129) clinical trials were combined to identify factors contributing to interindividual variability in daptomycin pharmacokinetics (PK). Over 30 covariates were considered. A two-compartment model with first-order elimination provided the best fit for data on daptomycin concentrations in plasma over time. In the final population PK model, daptomycin plasma clearance (CL) was a function of renal function, body temperature, and sex. Of these factors, renal function contributed most significantly to interindividual variability. CL varied linearly with the estimated creatinine clearance. CL among dialysis subjects was approximately one-third that of healthy subjects (0.27 versus 0.81 liter/h). CL in females was 80% that in males; however, in clinical trials, the outcome was not affected by sex and therefore this effect is not considered clinically meaningful. The relationship with body temperature should be interpreted cautiously since the analysis included only a limited number of subjects who were hyperthermic. The volume of distribution of the peripheral compartment (
V
2
) and intercompartmental clearance (
Q
) were linearly related to body weight.
V
2
increased approximately twofold in the presence of an acute infection. No factors were identified that significantly impacted
V
1
. This analysis supports the dosing of daptomycin on a milligram-per-kilogram-of-body-weight basis and suggests that modified dosing regimens are indicated for patients with severe renal disease and for those undergoing dialysis.
In Vitro Activities of ME1036 (CP5609), a Novel Parenteral Carbapenem, against Methicillin-Resistant Staphylococci
Authors: Kurazono Mizuyo , Ida Takashi , Yamada Keiko , Hirai Yoko , Maruyama Takahisa , Shitara Eiki , Yonezawa Minoru 
Published: July 2004

ABSTRACT

ME1036, formerly CP5609, is a novel parenteral carbapenem with a 7-acylated imidazo[5,1-
b
]thiazole-2-yl group directly attached to the carbapenem moiety of the C-2 position. The present study evaluated the in vitro activities of ME1036 against clinical isolates of gram-positive and gram-negative bacteria. ME1036 displayed broad activity against aerobic gram-positive and gram-negative bacteria. Unlike other marketed β-lactam antibiotics, ME1036 maintained excellent activity against multiple-drug-resistant gram-positive bacteria, such as methicillin-resistant staphylococci and penicillin-resistant
Streptococcus pneumoniae
(PRSP). The MICs of this compound at which 90% of isolates were inhibited were 2 μg/ml for methicillin-resistant
Staphylococcus aureus
(MRSA), 2 μg/ml for methicillin-resistant coagulase-negative staphylococci, and 0.031 μg/ml for PRSP. In time-kill studies with six strains of MRSA, ME1036 at four times the MIC caused a time-dependent decrease in the numbers of viable MRSA cells. The activity of ME1036 against MRSA is related to its high affinity for penicillin-binding protein 2a, for which the 50% inhibitory concentration of ME1036 was approximately 300-fold lower than that of imipenem. In conclusion, ME1036 demonstrated a broad antibacterial spectrum and high levels of activity in vitro against staphylococci, including β-lactam-resistant strains.