bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pyruvate Decarboxylase from Pisum sativum
Authors: Mücke Udo , Wohlfarth Thomas , Fiedler Ulrike , Bäumlein Helmut , Rücknagel Karl Peter , König Stephan 
Published: August 2004

To study the molecular structure and function of pyruvate decarboxylase (PDC) from plants the protein was isolated from pea seeds and partially characterised. The active enzyme which occurs in the form of higher oligomers consists of two different subunits appearing in SDS/PAGE and mass spectroscopy experiments. For further experiments, like X‐ray crystallography, it was necessary to elucidate the protein sequence.Partial cDNA clones encoding pyruvate decarboxylase from seeds of Pisum sativum cv. Miko have been obtained by means of polymerase chain reaction techniques. The first sequences were found using degenerate oligonucleotide primers designated according to conserved amino acid sequences of known pyruvate decarboxylases. The missing parts of one cDNA were amplified applying the 3′‐and 5′‐rapid amplification of cDNA ends systems. The amino acid sequence deduced from the entire cDNA sequence displays strong similarity to pyruvate decarboxylases from other organisms, especially from plants. A molecular mass of 64 kDa was calculated for this protein correlating with estimations for the smaller subunit of the oligomeric enzyme. The PCR experiments led to at least three different clones representing the middle part of the PDC cDNA indicating the existence of three isozymes. Two of these isoforms could be confirmed on the protein level by sequencing tryptic peptides. Only anaerobically treated roots showed a positive signal for PDC mRNA in Northern analysis although the cDNA from imbibed seeds was successfully used for PCR.
Purification and Catalytic Properties of Two Manganese Peroxidase Isoenzymes from Pleurotus eryngii
Authors: Martínez María J. , Ruiz‐Dueñas Francisco J. , Guillén Francisco , Martínez Ángel T. 
Published: August 2004

The ligninolytic basidiomycetes Pleurotus eryngii, Pleurotus ostreatus, Pleurotus pulmonarius and Pleurotus sajor‐caju did not exhibit detectable levels of manganese peroxidase (MP) when grown in liquid media with ammonium tartrate as N source. However, after examination of cells grown on different organic N‐based media, high MP activity was obtained in peptone medium, up to nearly 3 U/ml in cultures of P. eryngii. Moreover, Mn2+ supplementation was not used to produce MP, since all Mn2+ concentrations assayed (1–4000 μM) inhibited production of this enzyme in liquid medium.Two MP isoenzymes were purified to homogeneity from shaken or stationary cultures of P. eryngii grown in peptone medium. The purification process (which included chromatography on Biorad Q‐cartridge, Sephacryl S‐200 and Mono‐Q) attained 56% activity yield with a purification factor of 25. The isoenzymes differed in pI (3.75 and 3.65), N‐terminal sequence and some catalytic properties. They were in some aspects (e.g., molecular mass of 43 kDa) similar to Phanerochaete chrysosporium MP but exhibited some distinct characteristics, including Mn2+ ‐independent peroxidase activities against 2,6‐dime‐thoxyphenol and veratryl alcohol, and higher resistance to H2O2. Recent studies have shown that MP are ubiquitous enzymes in ligninolytic fungi, but the results obtained suggest that differences in catalytic properties probably exist between different Mn2+ ‐oxidizing peroxidases produced by these fungi.
Characterization of the Core Promoter of the Na+/K+‐ATPase α1 Subunit Gene
Authors: Kawakami Kiyoshi , Masuda Kazuyuki , Nagano Kei , Ohkuma Yoshiaki , Roeder Robert G. 
Published: August 2004

We have analyzed the core promoter element of the Na+/K+‐ATPase α1 subunit gene by means of an in vitro transcription system composed of a HeLa nuclear extract. 5′‐deletion and 3′‐deletion analyses revealed that this gene is specifically transcribed by RNA polymerase II in a manner that is dependent on the upstream regulatory region of the gene (−102 to −61), and that the 3′ boundary of the minimal promoter element does not extend beyond +5. Analysis of linker‐substitution mutations and point mutations revealed that the TATA‐like sequence (−33 to −26) is required for upstream‐sequence‐dependent transcription whereas linker‐substitution mutations and point mutations near +1 did not abolish transcription.The gene was found to be transcribed by RNA polymerase III when phosphocellulose column fractions were assayed. Deletion analysis mapped the minimal RNA‐polymerase‐III–specific promoter element from −49 to +17. The phosphocellulose 0.3‐M‐KCl fraction is absolutely required for transcription by RNA polymerase III, while the 0.85‐M‐KCl fraction represses aberrant transcription from incorrect initiation sites. Analysis of linker‐substitution mutations indicated that the TATA‐like sequence is required for RNA‐polymerase‐III–specific transcription. Although point mutations in the 5′ half of the TATA‐like sequence did not affect transcription, those in the 3′ half shifted the transcription initiation site 3 bp upstream. The results suggest that the Na+/K+‐ATPase α1 subunit gene promoter contains a TATA‐like sequence which can direct transcription by RNA polymerase III in vitro. The mechanism of alternative regulation of RNA polymerase II and RNA polymerase III is discussed.
Synthesis and Differential Properties of Creatine Analogues as Inhibitors for Human Creatine Kinase Isoenzymes
Authors: Min Kyung‐Lyum , Steghens Jean‐Paul , Henry Robert , Doutheau Alain , Collombel Christian 
Published: August 2004

Fourteen new creatine analogues, all with a guanidine function and either a polar or an apolar group instead of the creatine carboxylic function, were tested as potential inhibitors for human creatine kinase by kinetic analysis of their effects on the reaction rate. Only compounds bearing an apolar aromatic moiety, which was spaced from the guanidine function by at least two bonds, proved to have a significant inhibitory activity and showed a mixed‐type inhibition similar to that of creatine. Among these compounds 2,6‐dichlorobenzylguanidine (Ki= 5.6 mM and 39.8 mM for muscle‐type and brain‐type creatine kinases, respectively) and 3–(2,6‐dichlorophenyl)propylguanidine (Ki, = 15 mM and 4.5 mM) were the more potent inhibitors and showed a significant isoenzyme selectivity between muscle‐ and brain‐type creatine kinases.Our results are in agreement with recent data that suggest the location of a hydrophobic pocket near the guanidine‐binding domain of the enzyme. The observed selectivity in isoenzyme inhibition may be useful to study structural differences in catalytic centers.
Biotin‐Labelled and Photoactivatable Aldosterone and Progesterone Derivatives as Ligands for Affinity Chromatography, Fluorescence Immunoassays and Photoaffinity Labelling
Authors: Eisen Christoph , Meyer Christiane , Dressendörfer Regina , Strasburger Christian , Decker Heinz , Wehling Martin 
Published: August 2004

New derivatives of progesterone and aldosterone were synthesized and functionally tested with commercially available antibodies. The covalent labelling of antibodies specific for aldosterone and progesterone was detected by SDS/PAGE analysis and subsequent autoradiography after using 3‐(O ‐carboxymethyl)‐oximino‐(3‐[125I]iodo‐4‐azidosalicylamidobutylamine) derivatives of aldosterone and progesterone, respectively, as photoactivatable radioligands. Labelling was not observed in the presence of an excess of the unlabelled steroid.Aldosterone was labelled with biotin and used as a tracer in a time‐resolved fluorescence immunoassay. The nonradioactive tracer is highly selective for its antibody‐binding site, with almost no detectable cross‐reactivity for other steroids. Biotin‐labelled progesterone was immobilized by avidin‐agarose and used for affinity chromatography. This yielded a more than 20‐fold enrichment of an anti‐progesterone polyclonal antibody.These results demonstrate that derivatives of steroids are particularly useful for the development of nonradioactive assays for the determination of natural steroids and may be also useful for the detection of specific binding sites in biological material such as plasma membranes.
Synthesis, Characterization and Preliminary Crystallographic Data of N6‐(6‐carbamoylhexyl)‐FAD‐d‐amino‐acid Oxidase from Pig Kidney, a Semi‐Synthetic Oxidase
Authors: Stocker Achim , Hecht Hans‐Jürgen , Bückmann Andreas F. 
Published: August 2004

The FAD analogue, N6‐(6‐carboxyhexyl)‐FAD, carrying a hexanoic acid residue at the N6 position of the adenine moiety was synthesized. A new semi‐synthetic oxidase, N6‐(6‐carbamoylhexyl)‐FAD‐d‐amino acid oxidase, was prepared by reacting the succinimido ester of N6‐(6‐carboxyhexyl)‐FAD with apo‐d‐amino‐acid oxidase from pig kidney in the presence of benzoate. Reaction conditions and methods have been developed for preparing pure semi‐synthetic and fully active N6‐(6‐carbamoylhexyl)‐FAD‐d‐amino acid oxidase that contains 1 covalently bound FAD analogue/subunit, as verified by redialysis, ultraviolet spectrophotometry, electrospray ionization (ESI)‐MS and peptide mapping.Presumably, the N6‐(6‐carbamoylhexyl)‐FAD moiety of this semi‐synthetic d‐amino‐acid oxidase (DAAO), selectively bound to Lys163, has a structurally similar position to that of the non‐covalently bound FAD of the native holoenzyme, since both DAAO forms show very similar kinetic properties (semi‐synthetic DAAO, Vmax(app) = 17.7 μmol min‐1 mg‐1; KM(app) = 4.5 mM; native holo‐DAAO, Vmax= 12.2 μmol min‐1 mg‐1; KM= 1.8 mM). Compared with the native holo‐d‐amino acid oxidase, this new semi‐synthetic N6‐(6‐carbamoylhexyl)‐FAD‐d‐amino acid oxidase is a considerably more stable enzyme that shows meso‐thermostability and withstands inactivation on dilution. Probably, the lack of dissociation of FAD and, consequently, the absence of the instable apoenzyme are responsible for these phenomena. Preliminary investigations resulted in finding convenient and reproducible crystallization conditions for N6‐(6‐carbamoylhexyl)‐FAD‐d‐amino acid oxidase. The single crystals, obtained by the sitting‐drop method using ammonium sulfate as precipitant, belong to the tetragonal space group I422 with cell dimensions a= 16.3 nm, c= 13.6 nm. The crystals diffract to 0.3‐nm resolution, with two molecules being present in the asymmetric unit, demonstrating the two‐subunit quarternary structure of this semi‐synthetic D‐amino‐acid oxidase.
Sarco(Endo)Plasmic Reticulum Ca2+ Pump and Metabolic Enzyme Expression in Rabbit Fast‐type and Slow‐type Denervated Skeletal Muscles
Authors: Nozais Muriel , LomprÉ Anne‐Marie , Janmot Chantal , D'Albis Anne 
Published: August 2004

Recent reports by d'Albis et al. have shown that denervation of 8‐day‐old rabbit fast‐twitch muscle (gastrocnemius) leads to the transformation of the muscle towards a slow phenotype but the changes towards slow‐type myosin isoforms and contractile properties of the muscle were temporally uncoordinated. We analysed the time course of the effects of denervation of the gastrocnemius on the expression of the sarcoplasmic reticulum calcium pump isoforms (SERCA) and on the metabolic state of the muscle. Northern‐blot analysis showed a rapid loss of the fast Ca2+ pump isoform (SERCA 1) mRNA from the denervated gastrocnemius which became of the oxidative type. The changes observed were complete as early as 35 days post‐natal, i.e at the time when changes in contractile properties were previously observed. Denervation of the slow‐twitch soleus led to a 50% decrease in the level of the slow Ca2+ pump isoform (SERCA 2) mRNA and was without effect on the metabolic state of the muscle.These findings extend previous results suggesting that in rabbit, continuous innervation is required for differentiation of fast‐twitch muscles but is not an absolute requirement for differentiation of the slow‐twitch muscle.
Changes in distributed neural circuitry function in patients with first-episode schizophrenia
Authors: Mendrek A. , Laurens K. R. , Kiehl K. A. , Ngan E. T. C. , Stip E. , Liddle P. F. 
Published: August 2004

BackgroundA number of functional brain abnormalities have been reported in schizophrenia, but it remains to be determined which of them represent trait and state markers of the illness.AimsTo delineate regional brain dysfunctions that remain stable and those that fluctuate during the course of schizophrenia.MethodA cohort of patients with first-episode schizophrenia and a matched group of control participants underwent functional magnetic resonance imaging on two occasions 6–8 weeks apart during performance of a working memory task. The patients' disease was in partial remission at the second scan.ResultsRelative to control participants, the function of the left dorsolateral prefrontal cortex, left thalamus and right cerebellum remained disturbed in the people with schizophrenia, whereas the dysfunction of the right dorsolateral prefrontal cortex, right thalamus, left cerebellum and cingulate gyrus normalised, with significant reduction in symptoms.ConclusionsThese results suggest that dysfunction of the left fronto-thalamo-cerebellar circuitry is a relatively stable characteristic of schizophrenia, whereas disturbance of the right circuitry and cingulate gyrus is predominantly a state-related phenomenon.
Ethnicity, social deprivation and psychological distress in adolescents
Authors: Stansfeld Stephen A. , Haines Mary M. , Head Jenny A. , Bhui Kamaldeep , Viner Russell , Taylor Stephanie J. C. , Hillier Sheila , Klineberg Emily , Booy Robert 
Published: August 2004

BackgroundIn adults the prevalence of psychological distress varies in different ethnic groups, and this has been explained by differences in socio-economic status. Is this also the case in adolescents?AimsTo examine whether ethnic differences in prevalence of psychological distress in adolescents are associated with social deprivation.MethodA cross-sectional questionnaire survey was used to assess 2790 male and female pupils, aged 11–14 years, from a representative sample of 28 east London secondary schools.ResultsRates of psychological distress were similar to rates in UK national samples in boys and girls. Bangladeshi pupils, although highly socially disadvantaged, had a lower risk of psychological distress (OR=0.63, 95% CI 0.4–0.9). Non-UK White girls had higher rates of depressive symptoms (OR=1.54, 95% C11.1–2.2).ConclusionsHigh rates of depressive symptoms in non-UK White girls may be related to recent migration. Low rates of psychological distress in Bangladeshi pupils in this sample relative to White pupils, despite socio-economic disadvantage, could be associated with cultural protective factors that require further investigation.
Preventing crime by people with schizophrenic disorders: the role of psychiatric services
Authors: Hodgins S. , Müller-Isberner R. 
Published: August 2004

BackgroundKnowledge of when and how to implement treatments to prevent criminal offending among people with schizophrenia is urgently needed.AimsTo identify opportunities for interventions to prevent offending among men with schizophrenic disorders by tracking their histories of offending and admissions to hospital.MethodWe examined 232 men with schizophrenic disorders discharged from forensic and general psychiatric hospitals. Data were collected from participants, family members and official records.ResultsMore than three-quarters (77.8%) of the forensic patients had previously been admitted to general psychiatric services; 24.3% of the general psychiatric patients had a criminal record. Offences had been committed by 39.8% of the forensic patients and 10.8% of the general psychiatric patients before their first admission to general psychiatry, and after their first admission these 59 patients committed 195 non-violent and 59 violent offences. Subsequently, 49 of them committed serious violent offences that led to forensic hospital admission. The offenders were distinguished by a pervasive and stable pattern of antisocial behaviour evident from at least mid-adolescence.ConclusionsGeneral psychiatry requires resources in order to prevent criminal offending among a subgroup of patients with schizophrenic disorders.
What British psychiatrists read
Authors: Jones Teresa , Hanney Stephen , Buxton Martin , Burns Tom 
Published: August 2004

BackgroundThe role of journals in disseminating research to clinicians is increasingly debated. Current measures of esteem for journals (e.g. impact factors) may not indicate clinical penetration.AimsTo assess the perceived importance of different mental health journals to psychiatrists' clinical practice and compare this with impact factors.MethodRandom samples of psychiatrists providing child and adolescent, adults of working age and old age services chose up to ten journals read or consulted with regard to their clinical work, ranking the top three. For these journals, comparisons were made with impact factors and importance as outlets for UK psychiatry research.ResultsA total of 560 questionnaires were completed (47%). Two membership journals (the British Journal of Psychiatry and the BMJ) were most read and highest ranked. Associations between impact factors, clinicians' ratings and importance as outlets for psychiatry papers varied.ConclusionsThe results could lead to reconsideration of the importance of some journals. Academic assessments of the status of journals should not be assumed to reflect their influence on clinicians.
Audit of disposal of clinically confidential information
Authors: Dietrich Craige , Khan Zahir , Warner James 
Published: August 2004

Aims and MethodWe conducted a 3-cycle audit of disposal of clinically sensitive information in a mental health unit, in order to identify and reduce potential breaches in patients' confidentiality. Material from waste bins in administrative areas of a mental health unit was examined every evening during each period of the audit.ResultsThe first search, conducted over a 3-week period, yielded 11 documents containing highly-sensitive information about patients. After feedback to staff and improvement of shredding facilities, no sensitive information was found during the follow-up 3-week survey, 3 months later. However, a third survey 2 years later found 24 highly-sensitive items after one week, despite shredding facilities being maintained.Clinical ImplicationsChanges in behaviour identified in this audit appear to be due to education rather than improved facilities. All staff involved in patient care need to maintain awareness of the need for safe disposal of confidential material.
Cellular composition and ultrastructure of the gill epithelium of larval and adult lampreys
Authors: Bartels Helmut , Potter Ian C. 
Published: August 2004

SUMMARYLampreys, one of the only two surviving groups of agnathan (jawless)vertebrates, contain several anadromous species that, during their life cycle,thus migrate from fresh to seawater and back to freshwater. Lampreys have independently evolved the same overall osmoregulatory mechanisms as the gnathostomatous (jawed) and distantly related teleost fishes. Lamprey gills thus likewise play a central role in taking up and secreting monovalent ions. However, the ultrastructural characteristics and distribution of their epithelial cell types [ammocoete mitochondria-rich (MR) cell, intercalated MR cell, chloride cell and pavement cell] differ in several respects from those of teleosts. The ultrastructural characteristics of these cells are distinctive and closely resemble those of certain ion-transporting epithelia in other vertebrates, for which the function has been determined. The data on each cell type, together with the stage in the life cycle at which it is found, i.e. whether in fresh or seawater, enable the following proposals to be made regarding the ways in which lampreys use their gill epithelial cells for osmoregulating in hypo- and hypertonic environments. In freshwater, the intercalated MR cell takes up Cl– and secretes H+,thereby facilitating the uptake of Na+ through pavement cells. In seawater, the chloride cell uses a secondarily active transcellular transport of Cl– to provide the driving force for the passive movement of Na+ through leaky paracellular pathways between these cells.
The role of discontinuous gas exchange in insects: the chthonic hypothesis does not hold water
Authors: Gibbs Allen G. , Johnson Robert A. 
Published: August 2004

SUMMARY
Insects breathe through valved openings (spiracles) in their cuticle. Many insects open and close their spiracles in a cyclic pattern (discontinuous gas-exchange cycles, or DGC). These cycles were observed over half a century ago, their hypothesized function being to minimize loss of water from the tracheal system. However, numerous recent studies have found that respiration accounts for a small fraction of total water loss, and that insects stop performing DGC at times when this pattern would be most useful. Thus, the importance of cyclic gas exchange for water conservation has been challenged. The leading alternative is the chthonic hypothesis, which proposes that DGC originated in insects from hypercapnic (high CO2) environments(e.g. burrows) to aid in release of carbon dioxide. By keeping the spiracles closed, insects would concentrate CO2 and increase the gradient for outward diffusion of CO2. CO2 would be released rapidly when the spiracles opened, and respiratory water loss would be reduced. The chthonic hypothesis therefore predicts that DGC minimizes the ratio of respiratory water loss to CO2 release relative to other modes of gas exchange. We tested the chthonic hypothesis by simultaneously measuring water loss and CO2 release in reproductive females (queens) of the seed-harvester ant Pogonomyrmex barbatus, a burrowing species from North American deserts. Queens used one of three patterns of gas exchange,discontinuous, cyclic and continuous. We resolved the problem of separating cuticular transpiration and respiratory water loss for individuals that used continuous gas exchange by developing a regression method that can be used across all patterns of gas exchange. The ratio of respiratory water loss to CO2 release did not differ among ants using different patterns of gas exchange, in contrast to the expectation of the chthonic hypothesis. Metabolic rate, however, varied with gas-exchange pattern, and was lowest for individuals that used discontinuous gas exchange, intermediate for individuals using cyclic gas exchange, and highest for individuals using continuous gas exchange.
Recognition of calls with exceptionally fast pulse rates: female phonotaxis in the genus Neoconocephalus (Orthoptera:Tettigoniidae)
Authors: Deily Joshua A. , Schul Johannes 
Published: August 2004

SUMMARY
Male Neoconocephalus robustus and Neoconocephalus bivocatus produce remarkably fast calls, with pulse rates of approximately175–200 Hz. The temporal call patterns differ significantly between the two species. Male N. robustus produce calls with a single pulse rate of 200 Hz. In N. bivocatus, pulses are repeated with alternating periods, resulting in distinct pulse pairs: approximately 175 pulses s–1 are grouped into 87 pulse pairs s–1. In order to identify the temporal parameters used to recognize calls with such fast pulse rates, female call recognition in both species was tested during phonotaxis on a walking compensator. Female N. robustus were attracted to calls without amplitude modulation. Amplitude-modulated signals were equally attractive, as long as the silent intervals were short enough. The maximally tolerated interval duration varied with pulse duration. Female N. bivocatus did not require the paired-pulse pattern but were attracted to call models in which each pulse pair was merged into one long pulse. Females used the pulse rate to recognize such signals: pulse rates close to 87 Hz were attractive, largely independent of the duty cycle. Thus, females of the sibling species N. robustusand N. bivocatus used qualitatively different call recognition mechanisms.