bluuebunny/crossref_metadata_2025 huggingface dataset:
Utdanning for yrkeslivet: Samsvar mellom ferdigheter det undervises i og ferdigheter som etterlyses
Authors: Goth Ursula Småland , Schønfeldt Espen , Voll Liv Oddrun
Published: March 2021

Fagopplæringen i Norge består av en kombinert opplæring mellom skole og bedrift. Hovedmodellen bygger på to års opplæring i videregående skole (vg1 og vg 2) og to år som lærling i bedrift (vg 3). Ofte oppleves overgangen fra elev til lærling som vanskelig. Studien har som mål å belyse innholdet i elektroundervisningen, sammenhengen mellom lærerens grunnkompetanse i elektro og kartlegging av arbeidslivets behov. Studien hadde en kvalitativ og, en kvantitativ tilnærming og datagrunnlaget baserer seg på 15 faglærere i videregående skole og 38 opplæringsansvarlige i bedrifter i Oslo og Akershus fylkeskommune. Studien viser at innholdet i elektroopplæringen på yrkesfaglinjen teknisk industriell produksjon (TIP) i Oslo og Akershus er omfattende og dekker mange emner som arbeidslivet ikke vurderer som relevant for yrkesutøvelsen. Den store mengden fagområder legger i liten grad til rette for dybdelæring. Undervisningen krever ofte gode forkunnskaper i matematikk og naturfag, og dette er ikke tilpasset elevgruppens forutsetninger. Manglende fokus på sentralt fagstoff fører til at elevene manglet grunnleggende ferdigheter i sentrale fagemner ved overgang til lærlingetiden etter to år i videregående skole. Vi konkluderer med at elektroutdanning i TIP ikke oppnår relevant læringsutbytte for elevene ved overgang fra skole til lærlingetiden.
Indigenous Peoples and the Singular Socio-Political Trajectory of the Mbororo in Ngaoui Subdivision (Cameroon)
Authors: / ASSANA /
Published: March 2021

This study concerns the Mbororo of Ngaoui Sub-division (Cameroon). And for some good reasons: unlike those of Chad, Central African Republic (CAR) or certain regions of Cameroon such as the West, the Far North, the North and the East, where they constitute a vulnerable, dominated and marginalized group, the Mbororo of Ngaoui have succeeded in establishing themselves as a dominant group. This is due to their sedentarization caused by the boom in the cattle market, and accelerated by cross-border crimes in the 1970s. This sedentarization takes place through the diversification of their economic activities, openness to Christianity and access to health and educational infrastructures on one hand, and the relative possession of traditional power and above all, their central position in local politics on the other hand. By relying on the theory of the coloniality of power and empirical data collected in the localities where the Mbororos are highly established and their herds which are Djohong and Ngaoui. This contribution aims at analysing the singular socio-political trajectory of this Fulani fraction which does not respond to the definitional and identifying criteria enshrined in the international and Cameroonian conceptions, which makes them, indigenous, marginal and vulnerable populations respectively.
From Ataka to Kanjinchō: Adaptation of Text and Performance in a Nineteenth-Century Nō-Derived Kabuki Play
Authors: Saltzman-Li Katherine
Published: March 2021

Nō techniques and play borrowings provided important infusions into kabuki throughout its history, but in the nineteenth century, a genre of kabuki plays in close imitation of nō or kyōgen wasadded to the kabuki repertoire. The genre came to be called matsubamemono, meaning “[nō/kyōgen-derived kabuki] plays [performed] on a stage with a pine painted on the back wall” or “pine-boardplays.”1 These plays are the focus of this article, in which I first introduce the genre and its place in kabuki history, and then discuss its most famous example, the play Kanjinchō (Hattori 17–40; Meisakukabuki zenshū 181–197; Brandon, The Subscription List 205–236). Many matsubamemono are derived from fourth-category genzaimono nō plays. Kanjinchō is one such example, based on the genzaimono Ataka. Analysis of Kanjinchō will focus on the methods used to transform Ataka into Kanjinchō, methods that were used in other nō-to-kabuki matsubamemono adaptations and that resulted in a sophisticated amalgam of nō and kabuki techniques, borrowings and newly-created sections and passages. In addition, through an examination of the role of Benkei in performances by three great modern actors, I will briefly consider different ways of playing Benkei and how different interpretations affect our engagement with Benkei’s heroism, grandeur, and humanity.
COVID-19 Rapid Antigen Test: Role in Screening Prior to Gastrointestinal Endoscopy
Authors: Dalal Ashok , Sonika Ujjwal , Kumar Manish , George Roshan , Kumar Ajay , Srivastava Siddharth , Sachdeva Sanjeev , Sharma Barjesh Chander
Published: March 2021

Background/Aims: The severe acute respiratory syndrome coronavirus 2 pandemic has affected the gastrointestinal (GI) endoscopy units globally owing to the risk of transmission. We present our data on the use of rapid antigen test (RAT) as a screening tool prior to endoscopy to prevent the transmission of coronavirus disease (COVID-19).Methods: This study was a retrospective analysis of patients who underwent any GI endoscopic procedure from July 2020 to October 2020 at a tertiary referral center in New Delhi, India. All patients underwent screening for COVID-19 using RAT, and endoscopy was performed only when the RAT was negative. The data are presented as numbers and percentages.Results: A total of 3,002 endoscopic procedures were performed during the study period. Only one endoscopic procedure was performed in a COVID-19 positive patient. A total of 53 healthcare workers were involved in conducting these procedures. Only 2 healthcare workers (3.8%) were diagnosed COVID-19 positive, presumably due to community-acquired infection, during this period.Conclusions: The COVID-19 RAT is easily usable as a simple screening tool prior to GI endoscopy during the COVID-19 pandemic.
De la pulgada a los dígitos: preservación de materiales audiovisuales
Authors: Ollé Candela
Published: March 2021

Un buen tratamiento documental y garantizar su preservación son dos factores claves para poder conservar el patrimonio audiovisual de un país. Actualmente los procesos de digitalización son una realidad, pero todavía no han llegado a transformar digitalmente todo el fondo nacido analógico. La celebración del día mundial del Patrimonio Audiovisual y la reciente publicación de un artículo sobre la temática, han sido buenas excusas para hablar de ello.
La influencia de Mozilla en el periodismo
Authors: Domínguez Eva
Published: March 2021

Mozilla puede estar haciendo más por la innovación en el periodismo que mil gurús dando charlas. En su objetivo de expandir el código abierto, la apertura y la innovación en Internet, la Fundación Mozilla intenta inocular la cultura de la programación en las redacciones.
Del graznido al trino
Authors: Martínez Martínez Silvia
Published: March 2021

Hace unos meses el vaticanleaks, con la filtración de los documentos de la Santa Sede, obtenía resonancia en los medios. Ahora la atención ha pasado del graznar del particular cuervo del Vaticano a los trinos de la cuenta del Papa en Twitter. Y es que los tweets que ha empezado a publicar en @pontifex han despertado el interés de miles de usuarios del social media pero también de la prensa. Detrás de la inauguración de la cuenta, descubrimos una táctica de secuenciación de la información y una singular estrategia comunicativa que han logrado generar por el momento expectativa y muchas preguntas por responder.
Prevalence and clinical correlates of insomnia symptoms and their association with quality of life in Chinese patients with HBV-related liver disease
Authors: Zhao Jing , Liu Mei , Ungvari Gabor S. , Ng Chee H. , Chow Ines Hang Iao , Wang Ting , Chen Yu , Duan Zhongping , Xiang Yu-Tao , Zheng Su-Jun
Published: March 2021

Objective

This study aimed to describe the one-month prevalence of insomnia symptoms (insomnia hereafter) and the demographic and clinical correlates, and its association with quality of life (QOL) in Chinese patients with HBV-related liver disease.

Method

A total of 689 patients with HBV-related liver disease in Beijing, China formed the study sample. Three forms of insomnia including difficulty initiating sleep (DIS), difficulty maintaining sleep (DMS) and early morning awakening (EMA) were assessed using standardized questions. QOL was measured using the Medical Outcomes Study Short Form 12 (SF-12).

Results

The one-month prevalence of at least one type of insomnia was 69.5%, while DIS, DMS and EMA were 60.4%, 54.7% and 50.9%, respectively. Only 4.8% of patients suffering from insomnia received treatment. Multiple logistic regression analyses revealed that pre-existing medical conditions were positively associated with DIS and EMA; patients with more severe depressive symptoms were more likely to have DIS, DMS and EMA; local residents were less likely to have DIS; and those who were married and older were more likely to have DMS. Insomnia was not independently associated with QOL.

Conclusions

Insomnia is common in Chinese patients with HBV-related liver disease with a very low rate of treatment. Greater attention should be given to identify and treat insomnia in this patient population.
The influence of fish farm activity on the social structure of the common bottlenose dolphin in Sardinia (Italy)
Authors: Frau Serena , Ronchetti Fabio , Perretti Francesco , Addis Alberto , Ceccherelli Giulia , La Manna Gabriella
Published: March 2021

In a wide variety of habitats, including some heavily urbanised areas, the adaptability of populations of common bottlenose dolphin (Tursiops truncatus) may depend on the social structure dynamics. Nonetheless, the way in which these adaptations take place is still poorly understood. In the present study we applied photo-identification techniques to investigate the social structure of the common bottlenose dolphin population inhabiting the Gulf of Alghero (Sardinia, Italy), analysing data recorded from 2008 to 2019. The social structure analysis showed a division of the entire population into five different communities and the presence of non-random associations, while there was no evidence of segregation between sexes. Furthermore, results highlighted an important change in social structure through time, likely due to a reduction in fish farm activity since 2015. The division of the population into different communities, the presence of segregation based on the foraging strategy (inside or outside the fish farm area) and the social network measures were evaluated by analysing independently the two datasets: the intense and low farm activity periods: 2008–2014 and 2015–2020, respectively. Segregation among individuals belonging to the same foraging strategy class was found only in the earlier period, and the composition of the four communities was consistent with this result. Our study improves the knowledge about bottlenose dolphin adaptation, as a lower complexity in social structure was linked to a reduction in anthropogenic food availability.
Nonoperative Strategies to Manage Pain in Osteoarthritis during COVID-19 Pandemic
Authors: Jain Vijay Kumar , Iyengar Karthikeyan P , Upadhyaya Gauarv Kumar , Vaishya Raju , Nune Arvind
Published: March 2021

Corona Virus Disease (COVID-19) has resulted in restriction of face-to-face consultations and mechanisms to access health care. Oesteoarthritis (OA) is one of the most common forms of musculoskeletal disease encountered and a leading cause of painful disability in adults and elderly. The assessment of the challenges and strategies encountered in the nonoperative management of OA of knee care during the COVID-19 pandemic was done. A comprehensive review of the literature using suitable keywords such as ‘COVID-19’, ‘OA’, ‘OA knee’, ‘knee joint’ on the search engines of PubMed, SCOPUS, Google Scholar and Research Gate in May 2020 on developments and guidance during the current COVID-19 pandemic. The management of OA has been hampered by COVID-19 pandemic lock down with subsequent suspension of elective surgeries. Nonoperative complementary therapy has been evaluated with National Institute for Health and Care Excellence (NICE) recommendations to guide management. Conservative strategies including judicial use of analgesia as recommended by NICE, supportive orthosis, patient education and advice using remote telecommunication consultations play an important role in the nonoperative management of OA till elective surgery can safely resume.
Evidence for more than one pathway in the formation of purine deoxyribonucleotides
Authors: Foung A. , Norman A.W.
Published: July 2002

The biosynthesis of purine deoxyribonucleotides was studied in the context of general purine nucleotide metabolism in the chick with the aid of radioactive nucleic acid precursors. Our results showed that in chick liver and intestine, the nucleoside phosphate reductase system so firmly established in E. coli [1] and L. leichmanni [2] is not exclusively responsible for the biosynthesis of purine deoxyribonucleotides.
Untersuchungen zur Reaktivität von MetHb‐Untereinheiten
Authors: Blanck J. , Scheler W.
Published: July 2002

The kinetics of methaemoglobin substitution reactions have been investigated by the stopped‐flow technique. Biphasic reactions have been observed with adult and fetal methaemoglobin. This behaviour is attributed to different reactivities of the chain types. The investigations give evidence of an increasing chain reactivity in the sequence α‐chain < β‐chain < γ‐chain. The differences increase with the size of the substituting ligand, indicating steric effects.
L‐serine deaminating enzymes in Escherichia coli crude extracts
Authors: Alföldi L. , Raskó I.
Published: July 2002

(d) Conditions have been established in which threonine deaminases are eliminated and the activity of L‐serine deaminase alone could be measured, even in crude extracts.
Low‐energy Mg2+‐induced temperature transitions in liver microsomes
Authors: Akhrem A.A. , Kisel M.A. , Lunevich A.Ya. , Bokut S.B. , Andrianov V.T. , Kiselev P.A.
Published: July 2002

The differential scanning microcalorimetry and fluorescence methods, using probes ANS and pyrene, have been employed to study thermotropic behaviour of rat liver microsomes in the presence and absence of Mg2+. Addition of Mg2+ yields three partially reversible phase transitions at 18, 27 and 32°C, respectively. A character of Mg2+‐induced rearrangements in a membrane and their relation to a catalytic function of a cytochrome P‐450‐dependent enzymatic system discussed.
A novel glycerophosphodiesterase from Bacillus pumilus
Authors: Kusser Wolfgang , Fiedler Franz
Published: July 2002

A novel glycerophosphodiesterase activity was detected in extracts from phosphate‐starved Bacillus pumilus DSM27 cells. The enzyme had a substrate specificity for glycerophosphodiester bonds and the reaction product formed with partially purified enzyme was (sn)‐glycero‐3‐phosphate. Purified cell wall teichoic acid of the polyglycerophosphate type, as well as deacylated, unsubstituted lipoteichoic acid of the polyglycerophosphate type, di(glycerophospho)glycerol (deacylated cardiolipin) and mono(glycerophospho)glycerol (deacylated phosphatidylglycerol) served as substrates for the enzyme. Their native counterparts, however, cell wall‐bound polyglycerophosphate, lipoteichoic acid (D‐alanine substitued and dealanylated), cardiolipin and phosphatiylglycerol were poor or no substrates, respectively. Enzyme activity was inhibited by purified cell walls and by heparin. The enzyme was partially purified using a column of Heparin‐Sepharose.
Embryonic chick cartilage collagens
Authors: Kielty C.M. , Hulmes D.J.S. , Schor S.L. , Grant M.E.
Published: July 2002

The collagenous polypeptides present in embryonic chick sternal and tibiotarsal cartilages have been solubilised by digestion with pepsin and separated by salt fractionation. Type II collagen, 1α2α3α collagen, and two polypeptides (apparent molecular mass 150 and 42 kDa), which were reducible to a number of smaller peptides, were extracted from both tissues. However, also present in the peptic digests of tibiotarsal cartilages was a major non‐reducible highly‐soluble polypeptide of 45 kDa. This short‐chain collagen is apparently identical to the pepsinized product of G collagen (M
r 59 000), a major low‐M
r procollagen‐like species previously detected in chick chondrocyte cultures.
Amino acid neurotransmitters in the CNS: effect of thiopental
Authors: Pastuszko Anna , Wilson David F. , Erecinska Maria
Published: July 2002

Thiopental
Amino acid transport
GABA
Aspartate
Glutamate
Dopamine
Antigenic homologies between oat and wheat globulins
Authors: Fabijanski Steven , Altosaar Illimar , Laurière Michel , Pernollet Jean-Claude , Mossé Jacques
Published: July 2002

Total globulins of oat and wheat were compared by SDS‐electophoresis immunoblotting and in vitro protein synthesis experiments. Numerous homologies were found. The same 4 protein subgroups, with respect to molecular mass, were found in the two cereals. Immunoblotting with antibodies for total oat globulins allowed the detection of homologous proteins in each wheat protein group, especially in the 60‐kDa group, which corresponds to the major 12 S oat globulin. The same antibodies also reacted with in vitro synthesized proteins of the two cereals. However, compared to mature proteins, only a limited number of polypeptides react, suggesting that wheat globulins, like oat globulins, undergo post‐translational processes.
Epidermal growth factor stimulated protein kinase shows similar activity in liver of senescent and adult mice
Authors: Finocchiaro Liliana , Komano Odile , Loeb Jacques
Published: July 2002

It was recently reported [(1983) Nature 306, 617‐620] that tyrosine protein kinase activity associated with EGF receptor was absent from senescent human cultured fibroblasts, which are known to have the same number of receptors as young human cultured fibroblasts. We have measured in both adult and senescent C57 black mice the number of EGF receptors, the activity of their associated tyrosine kinase and the activity of the protein phosphatase which dephosphorylates the EGF receptor. We found our results in both groups of animals to be similar which indicate that the observations made in cultured fibroblasts cannot be generalized to all mammalian tissues.
Quantitation of plastoquinone‐9 in photosystem II reaction center particles
Authors: de Vitry Catherine , Carles Christophe , Diner Bruce A.
Published: July 2002

Quantitative analysis of PQ‐9 was performed on photosystem II reaction center particles isolated from Chlamydomonas reinhardtii. These particles show light‐driven electron transfer from secondary donor Z to primary quinone acceptor QA. If both Z and QA were PQ‐9, we would expect to find 2 PQ‐9/RC. Quantitative determinations indicate an average of 1.16 ± 0.14 PQ‐9/RC. As QA is not covalently bound to the RC (shown by QA reversible extraction and reconstitution) and as QA is known through optical spectroscopy to be a plastoquinone, we attribute the PQ‐9 to QA and conclude that Z is not a PQH2‐9.
Phosphorylation of the basal site of hormone‐sensitive lipase by glycogen synthase kinase‐4
Authors: Olsson Håkan , Strålfors Peter , Belfrage Per
Published: July 2002

In rat adipocytes hormone‐sensitive lipase is phosphorylated at two sites termed ‘regulatory’ and ‘basal’, in the former case by cyclic AMP‐dependent protein kinase causing an activation of the lipase [(1984) Proc. Natl. Acad. Sci. USA 81, 3317‐3321]. Here, the basal phosphorylation site was found to be phosphorylated by glycogen synthase kinase‐4 without any effects on lipase activity, or on the extent of its activation subsequent to phosphorylation of the regulatory site. Glycogen synthase kinase‐3, casein kinase‐I, and casein kinase‐II did not phosphorylate the lipase. Phosphorylase kinase phosphorylated it to a very low extent at a third phosphorylation site not phosphorylated in the fat cell.
Mastoparan binding induces a structural change affecting both the N‐terminal and C‐terminal domains of calmodulin
Authors: Linse Sara , Drakenberg Torbjörn , Forsén Sture
Published: July 2002

113Cd‐NMR studies of solutions of cadmium‐loaded calmodulin (Cd4CaM) and the tetradecapeptide mastoparan in different ratios show that mastoparan binds to Cd4CaM with high affinity. The off‐rate of proteinbound mastoparan is found to be 40 s−1 or less. The binding of one molecule of mastoparan to Cd4CaM is observed to affect all four metal‐binding sites, indicating that both the N‐terminal and C‐terminal globular domains of the protein undergo conformational changes.
Studies on the structure of the human C4b‐binding protein gene
Authors: Lintin Susan J. , Reid K.B.M.
Published: July 2002

Protein and cDNA sequence data have shown human C4b‐binding protein to contain eight internally homologous repeat units, each approx. 61 amino acids in length. Repeat units conforming to the same consensus sequence have been found in other complement and non‐complement proteins. Southern blot analysis together with isolation, characterisation and sequencing of genomic clones has allowed the study of intron/exon organisation in the human C4b‐binding protein gene and the identification of a Bg/II restriction fragment length polymorphism.
BliI, a restriction endonuclease from Bacillus licheniformis
Authors: Manachini P.L , Parini C. , Fortina M.G. , Benazzi L.
Published: July 2002

From Bacillus licheniformis a site‐specific restriction endonuclease, named BliI, has been purified and characterized. BliI was able to digest λ DNA at pH 9.1 over a wide temperature range (25–65°C). Digestion of λ and (ϕX174 DNAs with BliI produced banding patterns identical to those seen with HaeIII. Therefore, BliI and HaeIII endonculeases are isoschizomers.
Disulfide bonding as a determinant of the molecular composition of types I, II and III procollagen
Authors: Koivu Juha
Published: July 2002

Procollagen molecules have amino‐terminal and carboxy‐terminal propeptides at the respective ends of the collagenous triple helix. The carboxy‐terminal propeptides enhance and direct the association of proα‐chains into procollagen molecules, but the mechanism of this registration function is still obscure. A hypothesis concerning the function of disulfide bonding in the assembly of types I, II and III procollagen is put forward here.
Receptor‐mediated interaction of ricin with the lipid bilayer of ganglioside GM1‐liposomes
Authors: Utsumi Toshihiko , Aizono Yasuo , Funatsu Gunki
Published: July 2002

The interaction of ricin with ganglioside GM1 or glycoprotein containing liposomes was investigated. At neutral pH, ricin bound to galactose moieties on the surface of the liposomes to form ricin‐liposome complexes, but did not associate with their lipid bilayers. When these ricin‐liposome complexes were exposed to a pH below 5, ricin bound to GM1‐liposomes became associated with the lipid bilayer, whereas ricin bound to glycoprotein‐liposomes (containing human erythrocyte Band 3) was only rarely associated. Association of ricin with the lipid bilayer of GM1‐liposomes did not occur in the presence of lactose, which inhibits the binding of ricin to ganglioside GM1. Using a hydrophobic probe, 8‐anilino‐1‐naphthalene sulfonic acid (ANS), it was revealed that an acidity below pH 5 resulted in exposure of hydrophobic regions on the ricin molecule. These results strongly suggest that association of ricin with the lipid bilayer of GM1‐liposomes at acidic pH is mediated by the binding of ricin to ganglioside GM1 at neutral pH and occurs through interaction between the exposed hydrophobic region on the ricin molecule and the lipid bilayer of GM1‐liposomes at low pH.
A novel muramyl peptide derivative stimulates tumoricidal activity of macrophages and antibody production by B cells
Authors: Tenu Jean-Pierre , Adam Arlette , Souvannavong Vongthip , Barratt Gillian , Yapo Alexandre , Petit Jean-François , Level Michel , Clemance Martin , Douglas Kenneth
Published: July 2002

A novel analog of MDP, the 3′‐iodo‐4′‐azido‐L‐phenylalanine methyl ester derivative of N‐acetyl‐L‐alanyl‐D‐isoglutamine, has been prepared. This compound is capable of activating macrophages to the tumoricidal state and increasing the specific immune response of B cells. It thus appears to exhibit similar biological activities to MDP. Moreover, this compound is of potential interest for receptor photolabelling studies.
The amplified P‐signal, an extremely photosensitive light scattering signal from rod outer segments, which is not affected by pre‐activation of phosphodiesterase with Gα‐GTP‐γ‐S
Authors: Wagner Rafael , Ryba Nicholas J.P. , Uhl Rainer
Published: July 2002

A light scattering signal from bovine rod outer segments in the presence of GTP is described. It has the same angular dependence as the P‐signal but is 3 orders of magnitude more sensitive to light and therefore we have called in the amplified P‐signal. Adding Gα‐GTP‐γ‐S has no significant effect on the light scattering signal despite the activation of PDE. cGMP affects the amplified P‐signal, but subsequent addition of Gα‐GTP‐γ‐S restores the normal signal character. All these facts strongly support the view that the amplified P‐signal reflects G‐protein activation rather than that of PDE. This is in striking contrast to an interpretation of a very similar light scattering signal previously described by other groups.
Membrane capacity, measurements suggest a calcium‐dependent insertion of synexin into phosphatidylserine bilayers
Authors: Rojas Eduardo , Pollard Harvey B.
Published: July 2002

The mechanism by which synexin mediates calcium‐dependent aggregation of medullary cell chromaffin granules and fusion of granule ghosts involves specific interactions with the lipid component of the membrane. To study the details of these interactions we measured synexin‐induced changes in capacitance of phosphatidylserine bilayers formed at the tip of a patch pipet using the double‐dip method. Provided calcium was present in the solution filling the pipet (10–50 mM) stable phosphatidylserine bilayers were easily formed. Addition of synexin (0.1 μg/ml) to an external medium lacking added calcium induced no measurable changes in either bilayer resistance (10–30 GΩ) or displacement current across the membrane. However, addition of calcium (0.1–2.5 mM) in the presence of synexin in the external solution caused a marked increase in the size and time constant of decay of the displacement current. From the steady‐state value of the current we calculated a 5‐fold decrease in resistance and from the charge displaced during the voltage‐clamp pulses we calculated a 10‐fold increase in membrane capacitance (from 20 to 200 fF). The size of the synexin‐specific charge displacement in one direction during a pulse was always equal to the charge returning to the original configuration after the pulse. The synexin‐specific transfer of charge reached saturation when the pipet potential was taken to a sufficient positive or negative value. These properties of the extra charge movement support our view that in the presence of calcium the cytosolic protein synexin penetrates into the bilayer. It is possible that these properties may be related to the mechanism by which synexin promotes membrane fusion in natural membranes.
Functional activity of oligosaccharide‐deficient (Na,K)ATPase expressed in Xenopus oocytes
Authors: Takeda Kazuo , Noguchi Shunsuke , Sugino Atsuko , Kawamura Masaru
Published: July 2002

(Na,K)ATPase from Torpedo californica was expressed in Xenopus laevis oocytes in the presence of tunicamycin by injecting mRNAs for the α‐ and β‐subunits derived from the cloned cDNAs into the oocytes. The oligosaccharide‐deficient ATPase thus synthesized was transported to the oocytes plasma membrane, where it exhibited virtually the same ATPase activity, ouabain‐binding capacity and 86Rb+ transport activity as the fully glycosylated enzyme. We conclude that the oligosaccharide chains on the β‐subunit has no effect on the catalytic activities of (Na,K)ATPase.
Role of water activity on the rates of acetyl phosphate and ATP hydrolysis
Authors: de Meis Leopoldo , Suzano Valdecir Antunes
Published: July 2002

The rates of hydrolysis of acetyl phosphate in the presence of 0.1 M NaOH and of ATP in the presence of either 1 M HCl or 1 M NaOH were measured at different temperatures and in the presence of different concentrations of the organic solvents dimethyl sulfoxide or ethylene glycol. Under all conditions tested, there was a progressive increase in the rate constant of hydrolysis of both phosphate compounds as the water activity of the medium was decreased by the addition of organic solvents. At 25°C, substitution of 70% of the water of the medium by dimethyl sulfoxide promoted an increase of two orders of magnitude in the rate constant of acetyl phosphate hydrolysis. In the presence of 80% and 90% dimethyl sulfoxide the rate of acetyl phosphate hydrolysis increased by more than two orders of magnitude and was so fast that it could not be measured with the method used. The effect of organic solvents on the rate of ATP hydrolysis was less pronounced than that observed for acetyl phosphate hydrolysis. At 30°C, substitution of 90% of water by an organic solvent promoted a 4–6‐fold increase of the rate of ATP hydrolysis. Acceleration of either acetyl phosphate or ATP hydrolysis rates was promoted by a decrease in both activation energies (E
a) and in entropies of activation ΔS‡. The data obtained are discussed with reference to the mechanism of catalysis of enzymes involved in energy transduction such as the Ca2+‐ATPase of sarcoplasmic reticulum and the F1‐ATPase of mitochondria.
Identification of an allosteric site residue of a fructose 1,6‐bisphosphate‐dependent L‐lactate dehydrogenase of Thermus caldophilus GK24: production of a non‐allosteric form by protein engineering
Authors: Matsuzawa Hiroshi , Machida Masayuki , Kunai Kenji , Ito Yoshiyuki , Ohta Takahisa
Published: July 2002

Fructose 1,6‐bisphosphate (Fru‐1,6‐P2)‐dependent L‐lactate dehydrogenase (LDH) of Thermus caldophilus GK24 can be converted to a Fru‐1,6‐P2‐independent form on modification with Arg‐specific reagents. After trypsin digestion of the modified LDH, a peptide containing a modified Arg residue was purified and sequenced, and the modified Arg residue was identified as Arg‐173. Subsequently, Arg‐173 was replaced with Gln to remove the positive charge by site‐directed mutagenesis. The mutant LDH was independent of Fru‐1,6‐P2, like non‐allosteric vertebrate LDHs. Thus, Arg‐173 was concluded to be located in the allosteric site and to be responsible for allosteric regulation of the LDH.
Secretory responses of rat peritoneal mast cells to high intracellular calcium
Authors: Penner Reinhold , Neher Erwin
Published: July 2002

The patch‐clamp technique was used to investigate the secretory responses of rat peritoneal mast cells at various intracellular calcium concentrations ([Ca2+]i). When Calcium was introduced into the cell with pipette‐loaded dibromo‐BAPTA, elevation of [Ca2+]i into the range 1–10 μM induced membrane capacitance increases indicative of exocytosis in a concentration‐dependent manner. At higher concentrations a decrease of the response was observed. Cells that were exposed to micromolar [Ca2+]i underwent morphological alterations resulting in swelling, which is indicative of cytoskeletal alterations. The presence of dibromo‐BAPTA (4 mM) strongly inhibited secretion induced by GTP‐γ‐S, thus hampering the contribution of G‐protein‐mediated stimulation. Application of the Ca2+ ionophore ionomycin resulted in transient increases in [Ca2+]i which were parallelled by Ca2+‐dependent secretion. Effective buffering of the cytosolic calcium level below 1 μM abolished the secretory response. Our results show that an increase in [Ca2+]i can trigger secretion, but only if it is high and sustained. During physiological stimulation, however, secretion proceeds at [Ca2+]i below 1 μM. It is, therefore, concluded that mast cell degranulation under physiological conditions is not simply a result of an increase in [Ca2+]i, but that other second messenger systems in conjunction with calcium act synergistically in order to ensure fast and efficient secretion.
Evidence for the monomeric nature of thymosins
Authors: Haritos A.A. , Yialouris P.P. , Heimer E.P. , Felix A.M. , Hannappel E. , Rosemeyer M.A.
Published: July 2002

According to gel‐filtration experiments, α‐ and β‐thymosins appear to form oligomers, which are 4‐5‐fold larger than the corresponding polypeptides. However, on analysis by sedimentation equilibrium ultracentrifugation, prothymosin α and thymosin β4 showed relative molecular masses of 12 800 and 4600, which are close to the values calculated from their amino acid sequences, confirming their existence in solution as discrete monomeric entities.
Different selectivities of oxidants during oxidation of methionine residues in the α‐1‐proteinase inhibitor
Authors: Maier Konrad L. , Matejkova Eva , Hinze Helga , Leuschel Lieselotte , Weber Hans , Beck-Speier Ingrid
Published: July 2002

Oxidation of the reactive site methionine (Met) in α‐1‐proteinase inhibitor (α‐1‐PI) to methionine sulfoxide (Met(O)) is known to cause depletion of its elastase inhibitory activity. To estimate the selectivity of different oxidants in converting Met to Met(O) in α‐1‐PI, we measured the molar ratio Met(O)/α‐1‐PI at total inactivation. This ratio was determined to be 1.2 for both the myeloperoxidase/H2O2/chloride system and the related compound NH2Cl. With taurine monochloramine, another myeloperoxidase‐related oxidant, 1.05 mol Met(O) were generated per mol α‐1‐PI during inactivation. These oxidants attack preferentially one Met residue in α‐1‐PI, which is identical with Met 358, as concluded from the parallelism of loss of elastase inhibitory activity and oxidation of Met. A similar high specificity for Met oxidation was determined for the xanthine oxidase‐derived oxidants. In contrast, the ratio found for ozone andm‐chloroperoxybenzoic acid was 6.0 and 5.0, respectively, indicating oxidation of additional Met residues besides the reactive site Met in α‐1‐PI, i.e. unselective action of these oxidants. Further studies were performed on the efficiency of oxidants for total depletion of the elastase inhibitory capacity of α‐1‐PI. Ozone andm‐chloroperoxybenzoic acid were 10‐fold less effective and the superoxide anion/hydroxyl radicals were 30–50‐fold less effective to inactivate the elastase inhibitory activity as compared to the myeloperoxidase‐derived oxidants. The myeloperoxidase‐related oxidants are discussed as important regulators of α‐1‐PI activity in vivo.
Heme maintains catalytically active structure of cytochrome P‐450
Authors: Uvarov V.Yu. , Tretiakov V.E. , Archakov A.I.
Published: July 2002

Treatment of purified cytochrome P‐450 LM2 and its liposome‐bound form with hydrogen peroxide led to complete destruction of the P‐450 heme. The apoenzyme thus produced could be reconstituted to catalytically active cytochrome P‐450 by incubation with hemin, the reconstitution efficiency being 50% for the soluble enzyme and 80% for the liposome‐bound enzyme. The removal of heme from the soluble hemoprotein resulted in a 3‐fold decrease in the efficiency of its incorporation into sonicated liposomes. The contents of 5 secondary structure forms in the native, apoand reconstituted holoenzymes were estimated from their circular dichroism spectra. It was thus found that the helix content increased from 34% to 60% upon removal of the heme from the native enzyme. We suggest that the increase in the helix content leads to a reduction of the incorporation efficiency into liposomal membranes.
Gene expression during tuber development in potato plants
Authors: Prat S. , Frommer W.B. , Höfgen R. , Keil M. , Koßmann J. , Köster-Töpfer M. , Liu X.-J. , Müller B. , Pẽna-Cortés H. , Rocha-Sosa M. , Sánchez-Serrano J.J. , Sonnewald U. , Willmitzer L.
Published: July 2002

Potato tubers are modified stems that have differentiated into storage organs. Factors such as day‐length, nitrogen supply, and levels of the phytohormones cytokinin and gibberellic acid, are known to control tuberization. Morphological changes during tuber initiation are accompanied by the accumulation of a characteristic set of proteins, thought to be involved in N‐storage (i.e. patatin) or defense against microbial or insect attack (i.e. proteinase inhibitor II). Additionally, deposition of large amounts of starch occurs during tuber formation, which is paralleled by an increase in sucrose synthase and other enzymes involved in starch biosynthesis (i.e. ADP‐glucose pyrophosphorylase, starch synthases, and branching enzyme). Potential controlling mechanisms for genes expressed during tuberization are discussed.
Inositol 1,4,5‐trisphosphate activity in membranes isolated from amphibian skeletal muscle
Authors: Sánchez Ximena , Carrasco M.Angélica , Vergara Julio , Hidalgo Cecilia
Published: July 2002

The hydrolysis of [3H]inositol 1,4,5‐trisphosphate by a soluble fraction and by isolated transverse tubule and sarcoplasmic reticulum membranes from frog skeletal muscle was studied. Transverse tubule membranes displayed rates of hydrolysis several‐fold higher than those of sarcoplasmic reticulum and soluble fraction; K
m and V
max were 25.2 μM and 44.1 nmol/mg/min, respectively. Transverse tubule membranes sequentially hydrolyzed inositol trisphosphate to inositol bisphosphate, inositol 1‐phosphate and inositol. Indicating that these membranes have inositol bis‐ and monophosphatases in addition to inositol trisphosphatase.
Identification of individual amino acids in platelet‐derived growth factor that contribute to the specificity towards the β‐type receptor
Authors: Jaumann Monika , Tatje Dieter , Hoppe Jürgen
Published: July 2002

Platelet‐derived growth factor constitutes a family of three isoforms (PDGF‐AA, ‐AB, and ‐BB) composed of two homologous polypeptide chains (A and B). These isoforms interact with two types of receptors termed α or β. Whereas PDGF‐AA binds only to the α‐receptor, PDGF‐BB binds and activates both receptors with high affinity. To map regions that are specific for the β‐receptor, we introduced mutations into PDGF‐AA located in previously identified epitopes [1991, Biochemistry 30, 3303–3309]. A single amino acid exchange in domain II of PDGF‐AA (Ala67→Arg) was sufficient to bring about a reduced but significant activation of the β‐receptor. In domain I the exchange of residues Pro26→Arg together with Ser28→Asn switched the specificity towards the β‐receptor. These data indicate that parts of the exposed domains are indeed involved in receptor binding. Since these single mutations lead to mutant proteins which are about 100‐fold less active than PDGF‐BB, it is suggested that other amino acid residues also participate in the binding to the receptors.
Interaction of thioredoxin with oxidized aminobutyrate aminotransferase Evidence for the formation of a covalent intermediate
Authors: Park Joohong , Churchich Jorge E.
Published: July 2002

Pig brain 4‐aminobutyrate aminotransferase is inactivated by pre‐incubation with pyrroloquinoline quinone (2,7,9‐tricarboxy‐1H‐pyrrolo[2,3,f]quinoline‐4,5‐dione; PQQ) at pH 7. The reaction of approximately 2 SH residues/dimer is sufficient to inactivate the enzyme. Reoxidized aminotransferase is reactivated by E. coli thioredoxin. Similar results were obtained with E. coli 4‐aminobutyrate aminotransferase. The spectroscopic properties of thioredoxin, tagged with the fluorescence probe, anthraniloyl, were used to monitor its interaction with re‐oxidized 4‐aminobutyrate aminotransferase. During the regeneration of native aminotransferase by thioredoxin, the substrate forms a covalent intermediate with the oxireductase, as revealed by gel filtration chromatography. It is postulated that the substrate (oxidized aminotransferase) forms a covalent intermediate with thioredoxin through disulfide linkages.
Metribuzin resistance in photoautotrophic Chenopodium rubrum cell cultures
Authors: Schwenger-Erger Claudia , Thiemann Jutta , Barz Wolfgang , Johanningmeier Udo , Naber Dirk
Published: July 2002

Sequence analyses of eight metribuzin‐resistant mutants of photoautotrophic Chenopodium rubrum cell cultures revealed new mutations in the psbA gene coding for the 32 kDa herbicide binding protein. Mutants were found to possess either two or three changes in the amino acid sequence of the D1‐protein between positions 219 and 272.
Cloning and expression of a novel human profilin variant, profilin II
Authors: Honoré Bent , Madsen Peder , Andersen Annette H. , Leffers Henrik
Published: July 2002

We have isolated a 1.7 kbp cDNA encoding a 140 amino acid protein (15.1 kDa, pI 5.91) with a high sequence similarity (62%) to human profilin (profilin I). We have termed this variant profilin II. Northern blot analysis showed that profilin II is highly expressed in brain, skeletal muscle and kidney and less strongly in heart, placenta, lung and liver. In addition, three different transcript lengths were detected. Only one transcript of profilin I was found. The expression level of this was low in brain and skeletal muscle, medium in heart and high in placenta, lung, liver and kidney.
Crystallization and preliminary X‐ray analysis of leukemia inhibitory factor
Authors: Betzel Christian , Visanji Marcia , Dauter Zbigniew , Fourme Roger , Weber Wolfgang , Marnitz Ulf , Boone Thomas , Pope Joseph , Miller James , Hawkins Nessa , Samal Babru
Published: July 2002

Leukemia inhibitory factor (LIF) is a polyfunctional molecule with significant and diverse biological activities. LIF is a glycoprotein secreted by a number of different cell types in vitro. It is induced in fibroblasts, lymphocytes, monocytes and astrocytes by various inducers such as serum, TNF, interleukin‐IP and EGF. Due to extensive and variable glycosylation the molecular weight can range from 38 to 67 kDA. The biological functions of LIF are mediated through a receptor and a signal transducer, gp130, which is also used by factors like interleukm‐6 (IL‐6), cilliary neurotropic factor (CNTF), and oncostatin M (OSM). Here, we report the crystallization of the non‐glycosylated human‐like LIF expressed in E. coli. The present crystals diffract to 2.0 Å using synchrotron radiation. They belong to the monoclinic space group C2, and the cell dimensions are a = 61.5 Å, b = 45.3 Å , c =77.7 Å and β = 112.3°.
A new application for liposomes in cancer therapy
Authors: Vingerhoeds M.H. , Haisma H.J. , van Muijen M. , van de Rijt R.B.J. , Crommelin D.J.A. , Storm G.
Published: July 2002

We have tested a new type of immunoliposomes which may effectively mediate the targeting of enzymes to be used for site‐specific prodrug activation (immuno‐enzymosomes). The enzyme β‐glucuronidase, capable of activating the prodrug epirubicin‐glucuronide (epi‐glu), was coupled to the external surface of immunoliposomes directed towards ovarian cancer cells. A significant increase in cytotoxicity of the prodrug epi‐glu was shown when the in vitro cultured cancer cells were pretreated with these immuno‐enzymosomes.
Three‐dimensional model of NAD+‐dependent 15‐hydroxyprostaglandin dehydrogenase and relationships to the NADP+‐dependent enzyme (carbonyl reductase)
Authors: Krook Maria , Ghosh Debashis , Duax William , Jörnvall Hans
Published: July 2002

Modelling the amino acid sequence of NAD+‐linked 15‐hydroxyprostaglandin dehydrogenase into the three‐dimensional structure of 3α/20β‐hydroxysteroid dehydrogenase shows that these two enzymes, as well as the NADP+‐linked prostaglandin dehydrogenase (identical to carbonyl reductase) have similar conformations, in spite of very limited sequence identity (23–28%). Conservation of tertiary structures is greatest over the first two thirds of the polypeptide chains, where the typical NAD+ binding fold is retained, including the five first β‐strands, with only two short deletions or insertions up to residue 147. The remaining thirds of each of the prostaglandin dehydrogenases have significantly different architecture, including insertions that may contribute to enzyme specificity, and, except for an additional helix (αG), are difficult to model. Active site relationships can be evaluated and subunit interactions predicted, suggesting that the αE + αF two‐helix surface constitutes the major subunit interacting area, forming a dimeric unit in the oligomeric enzymes.
Tyr‐571 is involved in the T7 RNA polymerase binding to its promoter
Authors: Rechinsky V.O. , Tunitskaya V.L. , Dragan S.M. , Kostyuk D.A. , Kochetkov S.N.
Published: July 2002

The in vitro studies of three T7 RNA polymerase point mutants suggest that substitutions of Ala and Thr for Pro‐563 and of Ser for Tyr‐571 have little effect on the enzyme catalytic competence, but result in its inability to utilize the promoter. Both P563A and P563T mutants retain the promoter‐binding ability, whereas the promoter affinity of the Y571S mutant drops drastically.
Identification of the essential yeast protein MIM17, an integral mitochondrial inner membrane protein involved in protein import
Authors: Maarse Ammy C. , Blom Jolanda , Keil Petra , Pfanner Nikolaus , Meijer Michiel
Published: July 2002

We analyzed four Saccharomyces cerevisiae mutants defective in mitochondrial protein import and found that they are complemented by a novel gene encoding a 17 kDa protein. The protein is integrally located in the mitochondrial inner membrane and is termed MIM17. It shows significant homology to MIM23/Mas6p, a previously identified mitochondrial inner membrane protein required for the import of preproteins. Like MIM23, the precursor of MIM17 is synthesized without a presequence. A deletion of MIM17 is lethal. MIM17 thus joins the small group of mitochondrial proteins that are essential for the viability of yeast. We propose that MIM17 is an essential component of the preprotein import machinery of the mitochondrial inner membrane.
A toxin from the green mamba Dendroaspis angusticeps: Amino acid sequence and selectivity for muscarinic m4 receptors
Authors: Jolkkonen Mikael , van Giersbergen Paul L.M. , Hellman Ulf , Wernstedt Christer , Karlsson Evert
Published: July 2002

Muscarinic toxin 3 (MT3) (65 amino acids, four disulphides, M
r 7379) was isolated from the venom of the African snake Dendroaspis angusticeps (green mamba) and its amino acid sequence determined. Its ability to inhibit the binding of [3H]N‐methylscopolamine ([3H]NMS) to Chinese hamster ovary cells stably expressing subtypes of muscarinic receptors was studied. MT3 displayed high affinity for the m4 receptor (pK
i = 8.7 ± 0.06), 40‐fold lower affinity at m1 receptors (pK
i = 7.11 ± 0.17) whereas no inhibition of [3H]NMS binding to m2, m3 and m5 receptors was observed at concentrations up to 1 μM. This makes MT3 the most selective m4 receptor ligand known to date.
Mixing antifreeze protein types changes ice crystal morphology without affecting antifreeze activity
Authors: Heman Chao , DeLuca Carl I. , Davies Peter L.
Published: July 2002

All three fish antifreeze protein types (I, II and III) inhibit the growth of ice to form hexagonal bipyramidal ice crystals of characteristic morphology. Mixtures of these different antifreezes produced ice crystals of hybrid shapes and dimensions, consistent with the different antifreeze types binding to the same ice surfaces. The activity of the mixtures was independent of the proportions of the iso‐active antifreeze protein stocks present, indicating that the different antifreezes neither attenuated nor potentiated each other's activity. We suggest that antifreeze protein molecules are independently active and do not require protein‐protein interactions for ice‐binding.
A sequence analysis of the β‐glucosidase sub‐family B
Authors: Rojas A. , Romeu A.
Published: July 2002

This computational study is a summary of structural properties of the β‐glucosidase subfamily B. Computations were carried out using GCG package programs. All sequences used in this analysis were taken from the protein data bank. The multialignment and the phylogenetic tree of the β‐glucosidase subfamily B are shown. The conserved patterns: DGP, GRNFE, DPYL, KHF, SDW, GLD, VLLKN in the N‐terminal region and FGYGLSY in the C‐terminal part should be pointed out. C‐terminal parts of the Butyrivibrio fibrisolvens and Ruminoccocus albus β‐glucosidase sequences can be aligned to the N‐terminal region of the other members of the subfamily. A crossed homology model in sub‐family B β‐glucosidases is described.