bluuebunny/crossref_metadata_2025 huggingface dataset:
SYNTHESIS AND PROPERTIES OF NANOCELLULOSE-DYE CONJUGATES
Authors: Surov Oleg V. , Voronova Marina I. , Rubleva Natalia V. , Zakharov Anatoly G. , Afineevskii Andrei V.
Published: February 2021

Synthesis of conjugates of cellulose nanocrystals (CNC) with chlortriazine reactive dyes (RD) has been developed.  The obtained CNC-RD conjugates were characterized using a complex of modern methods: UV-Vis, IR and 13C solid state NMR spectroscopy, thermogravimetric and elemental analysis, particle size and zeta potential analysis, scanning electron and polarization optical microscopy. IR spectra of CNC-RD films show absorption bands typical of cellulose. The formation of a covalent cellulose-dye bond is confirmed by the presence of characteristic absorption bands of the resulting ether bond in the region of 1000-1300 cm-1. Based on the analysis of solid-state 13C NMR spectra, it was concluded that the degree of crystallinity of the CNC-RD conjugates does not change compared to the CNC, i.e. the RD covalently bind to the surface of the CNC particles and do not affect the crystal structure of the CNC. Using a simple model of CNC with square cross-section, and based on the elemental analysis data, the amount of covalently bound dye on the surface of CNC particles was estimated. The results obtained allow us to conclude that covalent bound of RD occurs selectively at one of the ends of the cellulose nanocrystal (the so-called reducing end of the cellulose polymer chain). Successful CNC surface modification is confirmed by UV-Vis spectroscopy. It was found that aqueous suspensions of CNC-RD conjugates have indicator properties. The sizes and charges of the particles of CNC-RD conjugates in dilute aqueous suspensions were determined. High colloidal stability of the CNC-RD aqueous suspensions was confirmed. It has been shown that CNC-RD colloidal suspensions possess liquid crystalline properties, which is clearly demonstrated by their iridescent color in polarized light with stirring. CNC films modified with RD also possess birefringence properties and exhibit an iridescent color in polarized light. The morphology of CNC-RD particles was studied using scanning electron microscopy. The thermal stability of the CNC-RD conjugates was studied.
Praktikeres risikovurderinger: brugen af risikofaktorer i forebyggelsen af ungdomskriminalitet
Authors: Ejrnæs Morten , Monrad Merete
Published: February 2021

AbstractSocial work practitioners support vulnerable children and youth who have problems or are at risk of developing problems. Increasingly, politicians and authorities are emphasizing the role of early crime prevention in social work and the role of risk factors in crime prevention.

However, there has not been a focus on how practitioners actually estimate the risk of a young person being apprehended as a first-time offender. We study practitioners’ risk assessments through three vignettes. The vignettes have been constructed using register- and survey-based research on the association between youth crime and a diversity of risk factors. The vignettes are thereby constructed to allow a comparison between the risk assessments of practitioners and the actual risk as demonstrated by the data. The study utilizes a sample of 312 health visitors, teachers (including nursery school teachers) and social workers.

The results indicate that practitioners grossly overestimate the risk of apprehension for first-time offences in all three vignettes. The average assessment of the risk is approximately 50 percentage points higher than the actual calculatedrisk. Furthermore, there is a large variation in the risk assessments given by different practitioners. Moreover, practitioners associate terms such as “high risk” with very different probabilities of crime.
Narrativer i Islamisk Stats propagandamagasin, Rumiyah – en digital tilgang til diskursanalyse
Authors: Kiis Emma Elisabeth
Published: February 2021

AbstractThis article uses messages communicated through the Islamic State’s propaganda magazine, Rumiyah, to explore the applicability of text mining methods in discourse analysis. The repertoire of narratives used in Rumiyah is examined through the theoretical framework of Narrative Criminology in combination with Discourse Theory, as presented by Ernesto Laclau and Chantal Mouffe. Techniques and methods from the field of digital text mining are also applied. The current article therefore has two sections: a quantitatively-deduced discourse analysis and a qualitatively-deduced discourse analysis.
L’anthropomorphisme des animaux dans les albums de littérature de jeunesse : état des lieux
Authors: Dionne Anne-Marie
Published: February 2021

L’anthropomorphisme est un procédé courant en littérature de jeunesse. Cependant, le fait d’octroyer des traits humains aux animaux risque d’entraver les connaissances et le raisonnement biologique des enfants concernant le règne animal, c’est-à-dire leur capacité à faire la distinction entre les propriétés biologiques propres aux animaux et les propriétés biologiques se rapportant spécifiquement aux êtres humains. Par cette recherche, nous examinons comment l’anthropomorphisme se manifeste dans des albums de littérature de jeunesse de langue française publiés au Canada. Une analyse de contenu portant sur 197 albums, que nous avons sélectionnés à partir de ceux ayant été répertoriés par la revueLurelusur une période de cinq ans (2013-2018), nous a permis de recenser les animaux représentés dans cet échantillon d’albums et de déterminer leur niveau d’anthropomorphisme, manifesté par l’entremise des textes et des illustrations. La façon dont sont présentées les propriétés biologiques des animaux a également été prise en compte. Nos résultats démontrent qu’une part importante des albums analysés présente des animaux qui sont anthropomorphisés et que lorsque leurs propriétés biologiques sont démontrées, elles peuvent rarement induire un raisonnement biologique chez les enfants.
Celestina: Documento bibliográfico (suplemento número 36)
Authors: Paolini Devid
Published: February 2021

N/A
Celestina: Documento bibliográfico (suplemento número 38)
Authors: Paolini Devid
Published: February 2021

N/A
To lie or not to lie: Super-relaxing with myosins
Authors: Nag Suman , Trivedi Darshan V
Published: February 2021

Since the discovery of muscle in the 19th century, myosins as molecular motors have been extensively studied. However, in the last decade, a new functional super-relaxed (SRX) state of myosin has been discovered, which has a 10-fold slower ATP turnover rate than the already-known non-actin-bound, disordered relaxed (DRX) state. These two states are in dynamic equilibrium under resting muscle conditions and are thought to be significant contributors to adaptive thermogenesis in skeletal muscle and can act as a reserve pool that may be recruited when there is a sustained demand for increased cardiac muscle power. This report provides an evolutionary perspective of how striated muscle contraction is regulated by modulating this myosin DRX↔SRX state equilibrium. We further discuss this equilibrium with respect to different physiological and pathophysiological perturbations, including insults causing hypertrophic cardiomyopathy, and small-molecule effectors that modulate muscle contractility in diseased pathology.
From ECG signals to images: a transformation based approach for deep learning
Authors: Naz Mahwish , Shah Jamal Hussain , Khan Muhammad Attique , Sharif Muhammad , Raza Mudassar , Damaševičius Robertas
Published: February 2021

Provocative heart disease is related to ventricular arrhythmias (VA). Ventricular tachyarrhythmia is an irregular and fast heart rhythm that emerges from inappropriate electrical impulses in the ventricles of the heart. Different types of arrhythmias are associated with different patterns, which can be identified. An electrocardiogram (ECG) is the major analytical tool used to interpret and record ECG signals. ECG signals are nonlinear and difficult to interpret and analyze. We propose a new deep learning approach for the detection of VA. Initially, the ECG signals are transformed into images that have not been done before. Later, these images are normalized and utilized to train the AlexNet, VGG-16 and Inception-v3 deep learning models. Transfer learning is performed to train a model and extract the deep features from different output layers. After that, the features are fused by a concatenation approach, and the best features are selected using a heuristic entropy calculation approach. Finally, supervised learning classifiers are utilized for final feature classification. The results are evaluated on the MIT-BIH dataset and achieved an accuracy of 97.6% (using Cubic Support Vector Machine as a final stage classifier).
High throughput virtual screening of 230 billion molecular solar heat battery candidates
Authors: Koerstz Mads , Christensen Anders S. , Mikkelsen Kurt V. , Nielsen Mogens Brøndsted , Jensen Jan H.
Published: February 2021

The dihydroazulene/vinylheptafulvene (DHA/VHF) thermocouple is a promising candidate for thermal heat batteries that absorb and store solar energy as chemical energy without the need for insulation. However, in order to be viable the energy storage capacity and lifetime of the high energy form (i.e., the free energy barrier to the back reaction) of the canonical parent compound must be increased significantly to be of practical use. We use semiempirical quantum chemical methods, machine learning, and density functional theory to virtually screen over 230 billion substituted DHA molecules to identify promising candidates. We identify a molecule with a predicted energy density of 0.38 kJ/g, which is significantly larger than the 0.14 kJ/g computed for the parent compound. The free energy barrier to the back reaction is 11 kJ/mol higher than the parent compound, which should correspond to a half-life of about 10 days—4 months. This is considerably longer than the 3–39 h (depending on solvent) observed for the parent compound and sufficiently long for many practical applications. Our paper makes two main important contributions: (1) a novel and generally applicable methodological approach that makes screening of huge libraries for properties involving chemical reactivity with modest computational resources, and (2) a clear demonstration that the storage capacity of the DHA/VHF thermocouple cannot be increased to >0.5 kJ/g by combining simple substituents.
A validation of Illumina EPIC array system with bisulfite-based amplicon sequencing
Authors: Noble Alexandra J. , Pearson John F. , Boden Joseph M. , Horwood L. John , Gemmell Neil J. , Kennedy Martin A. , Osborne Amy J.
Published: February 2021

The Illumina Infinium® MethylationEPIC BeadChip system (hereafter EPIC array) is considered to be the current gold standard detection method for assessing DNA methylation at the genome-wide level. EPIC arrays are often used for hypothesis generation or pilot studies, the natural conclusion to which is to validate methylation candidates and expand these in a larger cohort, in a targeted manner. As such, an accurate smaller-scale, targeted technique, that generates data at the individual CpG level that is equivalent to the EPIC array, is needed. Here, we tested an alternative DNA methylation detection technique, known as bisulfite-based amplicon sequencing (BSAS), to determine its ability to validate CpG sites detected in EPIC array studies. BSAS was able to detect differential DNA methylation at CpG sites to a degree which correlates highly with the EPIC array system at some loci. However, BSAS correlated less well with EPIC array data in some instances, and most notably, when the magnitude of change via EPIC array was greater than 5%. Therefore, our data suggests that BSAS can be used to validate EPIC array data, but each locus must be compared on an individual basis, before being taken forward into large scale screening. Further, BSAS does offer advantages compared to the probe-based EPIC array; BSAS amplifies a region of the genome (∼500 bp) around a CpG of interest, allowing analyses of other CpGs in the region that may not be present on the EPIC array, aiding discovery of novel CpG sites and differentially methylated regions of interest. We conclude that BSAS offers a valid investigative tool for specific regions of the genome that are currently not contained on the array system.
Somatic determinants of changes in selected body posture parameters in younger school-age children
Authors: Labecka Marta Kinga , Górniak Krystyna , Lichota Małgorzata
Published: February 2021

Background

The aim of this study was to describe changes in selected parameters of body posture in children between 5 and 9 years old with diversified somatic structures.

Methods

The study was carried out in 2015 and then repeated in 2018 among 67 participants who had previously been observed to have scoliotic posture. Basic body weight and height measurements were taken, which were then used to calculate the body mass index. Posture tests were conducted using the photogrammetric method.

Results

Girls and boys were not significantly different in body dimensions. With age, the number of overweight boys and children with normal growth-weight proportions increased. Temporary differences in posture variables indicating abnormalities were small.

Conclusions

There were no significant differences in somatic parameters between the girls and the boys. Those children with a slender body structure had the most abnormalities in the coronal plane. On the other hand, changes in spinal position in the sagittal plane were more frequent in overweight children. Relations were noted between the compensation index in the sagittal plane and deviation of the trunk inclination, the maximum deviation of the line of the spinous processes, and the angle of the shoulder line in the coronal plane and body mass index values were noted.
Exploring the occurrence of thioflavin-T-positive insulin amyloid aggregation intermediates
Authors: Ziaunys Mantas , Sakalauskas Andrius , Mikalauskaite Kamile , Smirnovas Vytautas
Published: February 2021

The aggregation of proteins is considered to be the main cause of several neurodegenerative diseases. Despite much progress in amyloid research, the process of fibrillization is still not fully understood, which is one of the main reasons why there are still very few effective treatments available. When the aggregation of insulin, a model amyloidogenic protein, is tracked using thioflavin-T (ThT), an amyloid specific dye, there is an anomalous occurrence of double-sigmoidal aggregation kinetics. Such an event is likely related to the formation of ThT-positive intermediates, which may affect the outcome of both aggregation kinetic data, as well as final fibril structure. In this work we explore insulin fibrillization under conditions, where both normal and double-sigmoidal kinetics are observed and show that, despite their dye-binding properties and random occurrence, the ThT-positive intermediates do not significantly alter the overall aggregation process.
Perception of Farmers on Maize as a Potential Crop for Climate Change Adaptation in Northern Bangladesh
Authors: Ali Muhiyadin Abdilahi , Karim Md. Rezaul , Ahmed Kawsar , Mondol Md. Abu Sayed
Published: February 2021

The main purposes of this research study was to determine the perception of farmers on maize as a potential crop for climate change adaptation and to access problems faced by the farmers in maize production. Maize cultivation is getting importance in Bangladesh, with economic efficiency of production estimated at 87%. Data were collected from the farmers of four villages of Biral Upazila under Dinajpur district in the Northern Bangladesh during 28 March to April 28 2018 from the 90 randomly sleeted farmers. Both descriptive and correlation coefficients test was performed for statistical analysis. Results revealed that almost three-fifths (61.10 percent) of the farmers had medium, while 20.00 percent of them had low and 18.90 percent had high perception of maize as a potential crop for climate change adaption. Correlation analysis indicated that age, education, cosmopoliteness, training received, knowledge on climate change and extension media contact of the farmers had significant positive relationships with their perception of maize as a potential crop for climate change adaption. On the contrary, farm size, maize cultivation area, farming experience and annual income had no significant relationship with their perception of maize as a potential crop for climate change adaption. ‘Non-availability of storage facilities’ was ranked as the 1st or top problems for maize production.  Other problems (in descending order) included ‘getting fair price problem due to interfere of middleman’, ‘non-availability of farm labour’, ‘lack of /or inadequate access to weather forecast technologies’, ‘no hybrid maize seed availability, ‘non-habit of human for consumption as food’, ‘poor information access regarding climate change adaptation strategies by maize farmers’, ‘lack of inputs in time’, ‘non-suitability of land for maize cultivation’, as well as ‘poor agricultural extension service delivery’. Further, it might be recommended that necessary support should be provided for the maize growers to minimize their problems on prioritize basis.
Forskolin stimulates adenylate cyclase and idodine metabolism in thyroid
Authors: van Sande J. , Cochaux P. , Dumont J.E.
Published: July 2002

Forskolin is a potent activator of the cyclic AMP‐generating system in many tissues. In dog thyroid slices, the enhancement of cyclic AMP level was rapid, sustained in the presence of forskolin, but easily reversible after its withdrawal. Contrary to TSH, forskolin induced little apparent desensitization. Forskolin potentiated the effects of TSH, PGE1 and cholera toxin. However, the forskolin‐induced cyclic AMP accumulation was still sensitive to inhibitors of dog thyroid adenylate cyclase such as iodide, norepinephrine and adenosine. As fluoride, but contrary to TSH and PGE1, forskolin stimulated adenylate cyclase in a medium where Mg2+ was replaced by Mn2+. This suggests that in thyroid, as in other tissues, forskolin acts beyond the receptor level but, as it potentiates hormone action and does not impair modulation by inhibitors, it may interact with the nucleotide‐binding regulatory proteins. Forskolin mimicked the effect of TSH on iodide organification and secretion.
Co‐ordinated regulation of muscle glycolysis and hepatic glucose output in exercise by catecholamines acting via α‐receptors
Authors: Clark Michael G. , Patten Glen S. , Filsell Owen H. , Rattigan Stephen
Published: July 2002

Recent findings indicate that glucose uptake by contracting hindlimb [Acta Physiol. Scand. (1982) 116, 215‐222] and heart [Biochem. Biophys. Res. Commun. (1982) 108, 124–131] of the rat is stimulated by epinephrine acting through α‐adrenergic mechanisms. Since in exercise hepatic glucose output may be increased markedly by activation of α‐adrenergic receptors and matched by the increase in muscle glucose uptake (maintaining blood glucose levels relatively constant), it is now proposed that a general coordination of glucose metabolism may operate via α‐adrenergic receptor mechanisms. The basis for this proposal is discussed.
The major outer membrane lipoprotein and new lipoproteins share a common signal peptidase that exists in the cytoplasmic membrane of Escherichia coli
Authors: Yamada Hisami , Yamagata Hideo , Mizushima Shoji
Published: July 2002

The cell envelope of Escherichia coli possesses several lipoproteins including the major outer membrane lipoprotein. These lipoproteins are synthesized as a signal peptide‐carrying precursor that is subsequently modified with glyceride. In this work, lipoprotein signal peptidase that processes the precursor of the major lipoprotein was partially purified from cells harboring a plasmid that carries the gene for this enzyme (1spA). The enzyme was also active against the glyceride‐containing precursors of the peptidoglycan‐associated lipoprotein and many additional membrane lipoproteins. The unmodified precursor of the major lipoprotein was not attacked by the enzyme. The enzyme was exclusively localized in the cytoplasmic membrane.
Two distinct polypeptides may be translated from a single spliced mRNA of the X genes of human T‐cell leukemia and bovine leukemia viruses
Authors: Sagata Noriyuki , Yasunaga Teruo , Ikawa Yoji
Published: July 2002

Human T‐cell leukemia and bovine leukemia viruses have a potential transforming gene, termed X. In addition to the major open reading frame known to encode a functional protein, the X gene harbors another short open reading frame which overlaps this major one. Both of these open reading frames are found on a single spliced X mRNA in a potentially functional form. Circumstantial evidence strongly suggests that they are both translated from the single X mRNA molecule, showing striking similarity to the translation mechanism of an adenovirus Elb gene mRNA. We note that the short open reading frame has the capability to encode a putative nuclear protein with structural features similar to those of an AIDS virus trans‐acting protein.
Purification and characterization of the gonad lectin of Aplysia depilans
Authors: Gilboa-Garber Nechama , Susswein Abraham J. , Mizrahi Lea , Avichezer Dody
Published: July 2002

Extracts of gonads and fertilized eggs of Aplysia depilans contain a D‐galacturonic and D‐galactose‐binding lectin. This lectin reacts strongly with rabbit and human erythrocytes independent of ABO blood groups, weakly with dog, mouse, rat, and chick erythrocytes and not at all or very weakly with sheep erythrocytes. Purification of the gonad lectin was easily achieved, with a high yield, by heating to 70°C, precipitation with ammonium sulfate and affinity chromatography on Sepharose 4B. The purified lectin was found to be a glucoprotein of molecular mass around 55–60 kDa; it stimulates mitogenesis of human peripheral lymphocytes.
Isolation and amino acid sequence of the smallest subunit of beef heart bc1 complex
Authors: Schägger Hermann , Borchart Ursula , Aquila Heinrich , Link Thomas A. , von Jagow Gebhard
Published: July 2002

The 11 subunits of beef heart bc
1 complex can be separated either by a new SDS‐PAGE system or by a series of Chromatographic steps involving dissociation of the complex by salt treatment. The amino acid sequence of the smallest subunit was determined by complete solid‐phase Edman degradation and was confirmed by sequencing the N‐terminal part and the C‐terminal tryptic fragment by liquid‐phase Edman degradation. The protein consists of 56 amino acid residues; the M
r was calculated to be 6363. The protein (‘ISP binding factor’) might be entangled in the reassembly of the iron‐sulfur protein with the bc
1 subcomplex.
Replacement of the deoxycytidine residues in Rhizobium bacteriophage RL38JI DNA
Authors: Swinton David , Hattman Stanley , Benzinger Rolf , Buchanan-Wollaston Vicky , Beringer John
Published: July 2002

Rhizobium phage RL38JI DNA is resistant to cleavage by a variety of restriction endonucleases, and is only partially sensitive to digestion by pancreatic DNase I or by micrococcal nuclease. We have found that a mixture of DNase I, P1 nuclease, and bacterial alkaline phosphatase will quantitatively digest RL38JI DNA to deoxyribonucleosides. HPLC analysis revealed that dCyd is nearly totally absent among these digestion products, while dGuo, dAdo, and Thd are readily detected. Three additional peaks are always present; their retention properties correspond to no known modified deoxyribonucleosides. Thus it appears that dCyd is replaced in phage RL38JI DNA by as many as 3 different modified residues.
Cyclic AMP stimulates dephosphorylation of specific proteins in intact S49 mouse lymphoma cells
Authors: Kiss Zoltán , Steinberg Robert A.
Published: July 2002

Two‐dimensional gel electrophoresis of proteins labeled with 32P1 in S49 mouse lymphoma cells revealed five phosphoproteins that were rapidly and reversibly dephosphorylated in response to elevation of cyclic AMP (cAMP). Under basal conditions, labeling of at least two of these proteins was limited by slow turnover of protein‐bound phosphate. The rapid cAMP‐mediated dephosphorylation of these species was attributable, therefore, to stimulation of a specific phosphoprotein phosphatase.
Are there proteins between the ribosomal subunits?
Authors: Yusupov Marat M. , Spirin Alexander S.
Published: July 2002

The hot tritium bombardment technique [(1976) Dokl. Akad. Nauk SSSR 228, 1237‐1238] was used for studying the surface localization of ribosomal proteins on Escherichia coli ribosomes. The degree of tritium labeling of proteins was considered as a measure of their exposure (surface localization). Proteins S1, S4, S7, S9 and/or S11, S12 and/or L20, S13, S18, S20, S21, L5, L6, L7/L12, L10, L11, L16, L17, L24, L26 and L27 were shown to be the most exposed on the ribosome surface. The sets of exposed ribosomal proteins on the surface of 70 S ribosomes, on the one hand, and the surfaces of 50 S and 30 S ribosomal subunits in the dissociated state, on the other, were compared. It was found that the dissociation of ribosomes into subunits did not result in exposure of additional ribosomal proteins. The conclusion was drawn that proteins are absent from the contacting surfaces of the ribosomal subunits.
EGF and insulin action in fibroblasts
Authors: L'Allemain Gilles , Pouysségur Jacques
Published: July 2002

Chinese hamster lung fibroblasts (CHL) arrested in G0 by serum starvation reinitiate DNA synthesis in response to either EGF, thrombin or serum. Arrested cells, prelabelled to equilibrium with [3H]inositol and receiving 20 mM LiCl prior stimulation, released rapidly large amounts of inositol phosphates when stimulated with thrombin or serum. In sharp contrast, EGF alone, or in association with insulin, failed to induce phosphoinositide breakdown at either early or late stages of EGF stimulation or in growing cells in EGF‐supplemented serum‐free medium. Phospholipase C remained, however, highly activatable by thrombin at all stages of EGF stimulation. Since EGF and thrombin are equally potent mitogens for CHL, we conclude that hydrolysis of polyphosphoinositides is not an exclusive signalling pathway for commitment to DNA replication and cell division.
Isolation and characterization of a cDNA clone for porcine thyroid peroxidase
Authors: Magnusson Ronald P. , Gestautas Jane , Seto Pui , Taurog Alvin , Rapoport Basil
Published: July 2002

We undertook the molecular cloning of porcine thyroid peroxidase (TPO). Four oligonucleotide probes were synthesized on the basis of amino acid sequences of 3 tryptic peptides from highly purified porcine TPO. These probes were used to screen a pig thyroid cDNA library. Seven of 16 selected clones (0.45–1.15 kb in size) reacted with all 4 probes. Nucleotide sequencing of the 1.15 kb at the 3'‐end of the structural gene revealed the complementary sequence to all 4 probes as well as the nucleotides coding for the entire length of the 3 tryptic peptides. There is an open reading frame of 332 amino acid residues. On Nothern blot analysis this gene codes for an mRNA species of 2.85 kb, corresponding to the anticipated size of the mRNA for the intact TPO molecule. We have therefore cloned and characterized a cDNA clone coding for approx. 36% of porcine thyroid peroxidase.
Identification of p26xb and p24xb of human T‐cell leukemia virus type II
Authors: Shima Hiroshi , Takano Masako , Shimotohno Kunitada , Miwa Masanao
Published: July 2002

Human T‐cell leukemia virus type II (HTLV‐II) isolated from a T‐cell variant of hairy cell leukemia contains gag, pol and env genes as well as a fourth gene termed X, which can code three major open reading frames Xa, Xb and Xc. Proteins with molecular masses of 26 kDa (p26xb) and 24 kDa (p24xb) encoded by the Xb open reading frame were identified with antisera directed against synthetic peptides corresponding to the N‐terminal and C‐terminal amino acid sequences deduced from the structure of the Xb open reading frame. More than half the Xb products were found to be located in the nuclear fraction of HTLV‐II‐infected cells.
Manganese elicits the synthesis of a novel exopolysaccharide in an arctic Rhizobium
Authors: Appanna Vasu D. , Preston Caroline M.
Published: July 2002

Under the influence of manganese (400μM), the arctic Rhizobium N11 [(1986) Arch. Microbiol. 146, 12–18] appeared to elaborate an exopolysaccharide that showed marked diversity with that synthesized in a medium deficient in added manganese. Both total carbohydrate and the uronic acid contents of these biomolecules appear to differ substantially. 13C‐NMR spectroscopy revealed three distinct signals in the anomeric region of the spectrum derived from the biopolymer secreted in the manganese rich medium, while that from the other exopolysaccharide exhibited numerous peaks. The resonance lines indicative of the non‐carbohydrate moieties were also found to be dissimilar. Further evidence for the unidentical nature of these biopolymers was obtained from viscosity and optical rotation measurements.
An AG→GG transition at a splice site in the myelin proteolipid protein gene in jimpy mice results in the removal of an exon
Authors: Macklin Wendy B. , Gardinier Minnetta V. , King Kit D. , Kampf Kathy
Published: July 2002

The myelin proteolipid protein gene was characterized in jimpy mice to identify the specific mutation that produces dysmyelination, oligodendrocyte cell death, and death of the animal by 30 days of age. Exon 5 and flanking intron segments were isolated from jimpy proteolipid protein genomic clones and sequenced. A single nucleotide difference was noted between the normal and jimpy proteolipid protein genes: the conversion of an AG/GT to a GG/GT in the splice acceptor signal preceding exon 5, which apparently destroys the splice signal. Thus, exon 5 of the mouse myelin proteolipid protein gene is skipped during the processing of mRNA, producing a shortened proteolipid protein mRNA.
Isolation of photosystem II reaction center complex by affinity chromatography with the peripheral 33‐kDa polypeptide as ligand
Authors: Isogai Yasuhiro , Yamamoto Yasusi , Yamamoto Yasuyuki , Nishimura Mitsuo
Published: July 2002

We report a procedure for one‐step isolation of the PS II reaction center complex from PS II particles by affinity chromatography with the peripheral 33‐kDa polypeptide as ligand. The CaCl2‐washed PS II particles prepared from spinach chloroplasts were solubilized with n‐octyl‐β‐d‐glucopyranoside and subjected to affinity chromatography. The purified complex consisted of polypeptides with apparent molecular masses of 47, 43, 32, 30 and 8 kDa.
Immunocytochemical localization of protein kinase C in resting and activated human neutrophils
Authors: Deli Eva , Kiss Zoltan , Wilson Emily , Lambeth J.David , Kuo J.F.
Published: July 2002

An immunocytochemical method was used to determine possible changes in the subcellular distribution of protein kinase C (PKC) in human neutrophils in response to opsonized latex beads and zymosan. While in resting cells most of the PKC immunoreactivity was localized in the cytoplasm, a redistribution of PKC to the plasma and phagosomal membranes was observed in cells treated with latex beads or zymosan for 5–20 min, suggesting a participation of PKC in endocytosis.
A comparison of the restrained molecular dynamics and distance geometry methods for determining three‐dimensional structures of proteins on the basis of interproton distances
Authors: Clore G.Marius , Nilges Michael , Brünger Axel T. , Karplus Martin , Gronenborn Angela M.
Published: July 2002

A direct comparison of the metric matrix distance geometry and restrained molecular dynamics methods for determining three‐dimensional structures of proteins on the basis of interproton distances is presented using crambin as a model system. It is shown that both methods reproduce the overall features of the secondary and tertiary structure (shape and polypeptide fold). The region of conformational space sampled by the converged structures generated by the two methods is similar in size, and in both cases the converged structures are distributed about mean structures which are closer to the X‐ray structure than any of the individual structures. The restrained molecular dynamics structures are superior to those obtained from distance geometry as regards local backbone conformation, side chain positions and non‐bonding energies.
Active sites of the cyclic GMP phosphodiesterase γ‐subunit of retinal rod outer segments
Authors: Lipkin V.M. , Dumler I.L. , Muradov K.G. , Artemyev N.O. , Etingof R.N.
Published: July 2002

Monoclonal antibodies were prepared to the γ‐subunit of the cGMP phosphodiesterase. One of them γp‐1, suppresses the activation of phosphodiesterase through the α‐subunit of transducin. The γ‐subunit fragment 24–45 rich in Arg and Lys residues is involved in γp‐1 binding and is essential for the γ‐subunit interaction with transducin. Carboxypeptidase Y cleaves off seven amino acid residues from the C‐terminus of the γ‐subunit resulting in phosphodiesterase activation. Thus, the C‐terminal fragment of γ‐subunit participates in phosphodiesterase inhibition.
Fatty acid uptake and metabolism to ketone bodies and triacylglycerol in rat and human hepatocyte cultures is dependent on chain‐length and degree of saturation Effects of carnitine and glucagon
Authors: Emmison Neil , Agius Loranne
Published: July 2002

Rat and human hepatocyte cultures were incubated with 5 common plasma longchain fatty acids (C16–C18). Rates of fatty acid uptake were similar in rat and human hepatocytes and were of the order: 16:1 > 16:0; 18:2 > 18:1 > 18:0. Rates of ketogenesis were lower in human compared to rat hepatocytes. In rat hepatocytes glucagon stimulated ketogenesis only in the presence of exogenous carnitine and rates of ketogenesis were higher from unsaturated compared to corresponding saturated fatty acids. Glucagon decreased triacylglycerol secretion irrespective of the fatty acid substrate and it increased intracellular triacylglycerol accumulation. The latter effect of glucagon was more marked in the absence of carnitine supplementation.
Characterization of cytochrome‐c oxidase mutants in human fibroblasts
Authors: Glerum D.Moira , Yanamura Wayne , Capaldi Roderick A. , Robinson Brian H.
Published: July 2002

Skin fibroblasts were selected as having cytochrome‐c oxidase deficiency by activity mesurements in whole cells. Each cell line was cultured in sufficient amount to isolate mitochondria for biochemical characterization. Cytochrome‐c oxidase was then examined by activity measurements, by heme determination and by polypeptide analysis using antibodies specific to the enzyme subunits. The cytochrome‐c oxidase activity in the different cell lines ranged from 9% to 54% of that of normal fibroblasts. Heme determinations and polypeptide analysis established that the lowered cytochrome‐c oxidase activity was due to reduced amounts of the complex in the mitochondrial inner membrane. In all cases, there was defective assembly of the enzyme, with the amounts of mitochondrially coded and nuclear coded subunits being reduced proportionally. These studies show that fibroblasts can be used for prenatal diagnosis of mitochondrial diseases and are a useful system in which to study mitochondrial biogenesis.
Occurrence and spacing of ribosome recognition sites in mRNAs of chloroplasts from higher plants
Authors: Ruf Michael , Kössel Hans
Published: July 2002

A computer‐aided search for potential ribosome recognition sequences of mRNAs from tobacco chloroplasts shows that more than 90% of mRNA species contain sequences upstream of the respective initiator codons, which allow base pairing with 3′‐terminal sequences of small subunit rRNA. This complementarity in several cases involves 16 S rRNA sequences between the canonical CCUCC sequence and the 3′‐terminal stem/loop structure. The distances between potential ribosome recognition sequences and initiator codons can be up to 25 nucleotides which is much greater when compared to the spacing of 7±2 nucleotides observed for the classical Shine‐Dalgarno sequences in bacterial mRNAs.
Hemispheric asymmetry of rapid chloride responses to inositol trisphosphate and calcium in Xenopus oocytes
Authors: Lupu-Meiri Monica , Shapira Hagit , Oron Yoram
Published: July 2002

Shallow injection of inositol 1,4,5‐trisphosphate (IP3) near the animal pole of the Xenopus oocyte resulted in a large depolarizing current that decayed rapidly. A similar injection near the vegetal pole produced a much smaller response characterized by a significantly slower rate of decay. Injection of CaCl2 near the animal pole of the oocyte resulted in a large depolarizing current characterized by rapid rise and decay times. Injection near the vegetal pole of the cell produced responses that exhibited similar amplitudes but much longer rise and decay times. The protein kinase C (PK‐C) activator, β‐phorbol 12‐myristate 13‐acetate (PMA), significantly enhanced the rapid responses to IP3 injections at either hemisphere but did not affect the amplitudes of the responses to CaCl2. The PK‐C inhibitor 1‐(5‐isoquinolinylsulfonyl)‐2‐methylpiperazine (H‐7) had no effect on the responses to CaCl2. These results imply an asymmetric distribution of calcium stores and chloride channels between the two hemispheres of the oocyte.
γ‐Subunit of mouse retinal cyclic‐GMP phosphodiesterase: cDNA and corresponding amino acid sequence
Authors: Tuteja Narendra , Farber Debora B.
Published: July 2002

The cDNA nucleotide and corresponding amino acid sequences of the γ‐subunit of cyclic‐GMP phosphodiesterase (cGMP‐PDEγ) from mouse retina have been determined. The cDNA translated region was found to be 91.5% homologous to the cDNA coding region for the enzyme from bovine retina [(1986) FEBS Lett. 204, 288–292]. On Northern blots of normal mouse retinal RNAs this cDNA hybridized the cGMP‐PDEγ mRNA which is 900 bp long. The mouse γ‐subunit contains 87 amino acid residues which share 97.7% homology with the bovine polypeptide [(1986) FEBS Lett. 204, 288–292]. Only two amino acids have been changed, Ala 8 to Gly and Met 17 to Ile.
High incorporation of dietary 1‐O‐heptadecyl glycerol into tissue plasmalogens of young rats
Authors: Das Arun K. , Hajra Amiya K.
Published: July 2002

When 1‐O‐heptadecyl‐rac‐glycerol was fed (20 mg/g of food) to 19‐day‐old rats for 10 days, a high incorporation of the heptadecyl group into the 1‐O‐alk‐1′‐enyl group of ethanolamine plasmalogens of all tissues was observed. For example, 62% of the alkenyl groups from liver plasmalogen was of the 17:0 variety. The analogous values for other tissues were 62% in kidney, 57% in lung, 57% in heart, 50% in intestine, 43% in erythrocytes, 25% in testis and 8% in brain. The corresponding figures in the control rats (fed normal rat chow) were only 2–3% of 17:0 for all tissues. Available evidence indicates that dietary 1‐O‐heptadecyl‐sn‐glycerol is utilized to form tissue plasmalogens without the cleavage of the ether bond. The relevance of these results to the possible dietary ether lipid therapy of patients suffering from congenital ether lipid deficiency is discussed.
Mitochondrial sulfhydryl group modification by adriamycin aglycones
Authors: Sokolove Patricia M.
Published: July 2002

Induction of Ca2+ release from isolated, preloaded rat heart mitochondria by low concentrations (<5 μM) of adriamycin aglycones, has recently been reported [(1988) Biochem. Pharmacol. 37, 803]. Ca2+ release occurs via a generalized, Ca2+‐dependent increase in the permeability of the inner mitochondrial membrane to small molecules. The process is antagonized by dithiothreitol, suggesting thiol involvement. This communication demonstrates modification of mitochondrial sulfhydryl groups, detected as decreased 5,5′‐dithiobis‐(2‐nitrobenzoic acid) (DTNB) reactivity, by adriamycin aglycones. Ca2+ release and sulfhydryl modification are shown to depend similarly on aglycone concentration and on the C‐7 substituent of the anthracycline ring. In addition, DTNB elicits Ca2+ release. It can therefore be proposed that adriamycin aglycones alter mitochondrial membrane permeability by altering mitochondrial thiol status.
Identification of the α3‐subunit in the GABAA receptor purified from bovine brain
Authors: Stephenson F.Anne , Duggan Michael J. , Casalotti Stefano O.
Published: July 2002

Polyclonal antibodies have been raised to synthetic amino acid sequences of the bovine GABAA receptor α1 and α3 subunits. Anti‐α1 subunit antibodies recognise a polypeptide of 53 kDa whereas anti‐α1 subunit antibodies recognise a polypeptide of 59–60 kDa, in Western blots of GABAA receptor purified from adult bovine cerebral cortex, cerebellum and 12‐day calf cerebral cortex.
Preparation of 2‐azidoadenosine 3′,5′‐[5′‐32P]bisphosphate for incorporation into transfer RNA Photoaffinity labeling of Escherichia coli ribosomes
Authors: Sylvers Lee A. , Wower Jacek , Hixson Stephen S. , Zimmermann Robert A.
Published: July 2002

2‐Azidoadenosine was synthesized from 2‐chloroadenosine by sequential reaction with hydrazine and nitrous acid and then bisphosphorylated with pyrophosphoryl chloride to form 2‐azidoadenosine 3′,5′‐bisphosphate. The bisphosphate was labeled in the 5′‐position using the exchange reaction catalyzed by T4 polynucleotide kinase in the presence of [γ‐32P]ATP. Polynucleotide kinase from a T4 mutant which lacks 3′‐phosphatase activity (ATP:5′‐dephosphopolynucleotide 5′‐phosphotransferase, EC 2.7.1.78) was required to facilitate this reaction. 2‐Azidoadenosine 3′,5′‐[5′‐32P]bisphosphate can serve as an efficient donor in the T4 RNA ligase reaction and can replace the 3′‐terminal adenosine of yeast tRNAPhe with little effect on the amino acid acceptor activity of the tRNA. In addition, we show that the modified tRNAPhe derivative can be photochemically cross‐linked to the Escherichia coli ribosome.
Liposome‐associated retinoic acid
Authors: Nastruzzi Claudio , Walde Peter , Menegatti Enea , Gambari Roberto
Published: July 2002

The activity of liposome‐associated retinoic acid was analyzed on in vitro cultured tumor cell lines and compared to the antiproliferative effects of free retinoic acid. It was found that liposome‐associated retinoic acid is about 300 times more active than free retinoic acid in inhibiting in vitro cell growth of leukemic and melanoma cell lines. An increased activity of retinoic acid (10–20 times) was also obtained after premixing of this compound with empty liposomes, demonstrating that the retinoic acid efficiently interacts with liposomes which may facilitate solubility and cell uptake of retinoids.
Distribution of inositol 1,4,5‐trisphosphate receptor mRNA in mouse tissues
Authors: Furuichi Teiichi , Shiota Chiyo , Mikoshiba Katsuhiko
Published: July 2002

Northern blot analysis demonstrated that the concentration of inositol 1,4,5‐trisphosphate (IP3) receptor mRNA was greatest in cerebellar tissue. Moderate amounts of IP3 mRNA were present in brain tissue without cerebellum and tissue of the thymus, heart, lung, liver, spleen, kidney, and uterus. Small amounts of IP3 receptor mRNA were observed in skeletal muscle and testicular tissue. Regional distribution of IP3 mRNA in various tissues was also examined by in situ hybridization. A considerable amount of IP3 receptor mRNA was located in smooth muscle cells, such as those of the arteries, bronchioles, oviduct and uterus. In addition, secondary oocytes surrounded by Graafian follicles in the ovary were found to have large amounts of IP3 receptor mRNA. The present studies suggest a functional importance of the IP3 second‐messenger system in these cell types.
Purification and characterization of E37, a major chloroplast envelope protein
Authors: Block Maryse A. , Joyard Jacques , Douce Roland
Published: July 2002

We have purified to homogeneity E37, the second major polypeptide of the inner membrane of the chloroplast envelope. The protein was retained on a Mono S column at pH 7, indicating it is a basic protein. After cyanogen cleavage, the protein was partially sequenced at 2 different sites. The sequence is compared with the deduced amino acid sequence of a cDNA coding for a 37 kDa envelope polypeptide recently published by Dreses‐Werringloer et al. (Eur. J. Biochem. (1991) 195, 361‐368.)
Purification and some properties of the pectin lyase from Penicillium italicum
Authors: Alaña Aitor , Llama Maria J. , Serra Juan L.
Published: July 2002

For the first time, a pectin lyase (poly(methoxygalacturonide)lyase; EC 4.2.2.10) from a member of the generus Penicillium was isolated, purified to homogeneity and characterized. The monomeric enzyme from Penicillium italicum CECT 2294 culture filtrates showed a molecular mass of 34 kDa after SDS‐electrophoresis in polyacrylamide gradient gels, and the isoelectric point was 8.6 as determined by isoelectric focusing. The optimum pH (9.0), the high pH and temperature stabilities, the ability to degrade pectins from different sources and with a wide range of degrees of esterification (from 37% to 86%) as well as the importance of this type of biocatalysts in the food industry make this enzyme an interesting subject of study.
Inverse regulation of glucose transporter Glut4 and G‐protein Gs mRNA expression in cardiac myocytes from insulin resistant rats
Authors: Petersen Simone , Russ Martina , Reinauer Hans , Eckel Jürgen
Published: July 2002

The present study examined the mRNA levels of glucose transporter Glut4 and G‐protein Gs α‐subunit in isolated ventricular myocytes from lean and genetically obese (fa/fa) Zucker rats and streptozotocin‐diabetic rats. In obese animals the amount of transcripts coding for Glut4 increased to 122±6% of lean controls, whereas the mRNA coding for Gs α‐subunit decreased by 42±12%. An unaltered level of Gs mRNA was observed in insulin deficient rats. When cardiomyocytes from normal rats were treated with insulin, the Glut4 transcript level increased by 48±5%, whereas the Gs mRNA level decreased by 55±8%. The findings suggest that insulin may act as a potential regulator of Glut4 and Gs mRNA expression in the cardiac cell.
Folding intermediates of hyperthermophilic D‐glyceraldehyde‐3‐phosphate dehydrogenase from Thermotoga maritima are trapped at low temperature
Authors: Schultes Verena , Jaenicke Rainer
Published: July 2002

D‐Glyceraldehyde‐3‐phosphate dehydrogenase from the hyperthermophilic eubacterium, Thermotoga maritima, is extremely thermostable showing a thermal transition beyong 105°C. At low temperature, ‘cold denaturation’ becomes detectable only in the presence of destabilizing agents. Reconstitution after preceding denaturation depends on temperature. At 0°C, no significant recovery of activity is detectable, whereas between 30 and 100°C reactivation reaches up to 85%. Shifting the temperature from low values to the range of optimum reconstitution releases the trapped intermediate in a fast reaction. Evidence from ultra‐centrifugal analysis and far‐UV circular dichroism proves the intermediate to be partially assembled to the tetramer, with most of its native secondary structure restored in a fast reaction. Fluorescence emission exhibits at least biphasic kinetics with the rate‐limiting step(s) reflecting local adjustments of aromatic residues involved in tertiary contacts in the native state of the enzyme.
Phosphorylation of α‐crystallin B in Alexander's disease brain
Authors: Mann Eric , McDermott Martin J. , Goldman James , Chiesa Raúl , Spector Abraham
Published: July 2002

The phosphorylation of α‐crystallin B was studied in homogenates of autopsy samples of brain tissue from patients with Alexander's disease, a condition characterized by over‐expression of this protein. After incubation in the presence of [γ‐32P]ATP and cAMP the homogenates were analyzed by two‐dimensional electrophoresis, (isoelectric focusing followed by SDS‐PAGE). Three major polypeptides having the same molecular weight as bovine lens α‐crystallin B and pIs 7.1, 6.9 and 6.7 were detected in the Coomassie blue stained gels. These three polypeptides were recognized by an α‐crystallin B‐specific antiserum in Western blots. The polypeptides with pIs 7.1 and 6.7 co‐migrated in isoelectric focusing gels with bovine lens αB and its phosphorylated form αBp, respectively. Radioautography of the two‐dimensional gels demonstrated the presence of 32P in the most acidic polypeptide. The results demonstrate the occurrence of αB phosphorylation in Alexander's disease brain tissue.