bluuebunny/crossref_metadata_2025 huggingface dataset:
Factors affecting dry eye syndrome and quality of life among college students in Korea: a cross-sectional study
Authors: Cho Mi-Kyoung , Yoon Seonhwa , Cho Yoojin , Jun Younhye , Choi Jiseon , Ryu Minyoung , Kim Myeong Jin , Sung Ga Hyun
Published: February 2025

Purpose: This study aimed to identify the factors affecting dry eye syndrome and quality of life (QoL) among college students. Methods: This cross-sectional study administered a descriptive survey to 184 college students across Korea. Data collection was conducted from August 27 to 28, 2024, using an online survey platform (Google Forms). The self-reported survey comprised the Health-Related Quality of Life Instrument with 8 Items scale, the Dry Eye Questionnaire 5, and the Ocular Surface Disease Index. Data analysis was performed using SPSS version 27.0. Results: The participants had a mean age of 21.37 (standard deviation 1.96) years. Regression analysis identified sleep satisfaction, vision-related functions, and dry eye symptoms as statistically significant predictors of QoL, accounting for 18.4% of the variance (F = 14.71, p < .001). Dry eye symptoms were significantly influenced by the use of artificial tears, vision-related functions, and environmental factors, which accounted for 41.3% of the variance (F = 43.93, p < .001). Additionally, significant determinants of ocular surface disease included the use of vision correction tools, the presence of ophthalmic diseases, sleep satisfaction, and dry eye symptoms. These factors explained 45.7% of the variance, confirming the model's robustness (F = 31.84, p < .001). Conclusion: It is necessary to identify strategies to alleviate dry eye syndrome in college students and develop comprehensive prevention and management programs to improve their QoL.
Diversity of Floral Visitors and Foraging Behaviour of Major Bee Species on Buckwheat (Fagopyrum esculentum M.)
Authors: B Gagan , G Eswarappa , S Anitha , K S Jagadish
Published: February 2025

Buckwheat flowers attract a diverse range of insect floral visitors contributing to pollination. This study aims to assess their diversity, dominance and foraging behaviour of major bee species on the pin and thrum morphs of buckwheat during different blooming phases. A total of 46 insect species visited buckwheat flowers, which included both Apis and non-Apis species, out of which 21 species were from Hymenoptera, 14 species from Diptera, six from Lepidoptera, three from Hemiptera and two from Coleoptera. The Berger-Parker dominance index for floral visitors on pin morph and thrum morph of buckwheat varied among different blooming phase with Apis cerana F. being the most dominant visitor throughout blooming phase. The diversity of floral visitors was highest during maximum bloom phase on pin and thrum morph as compared to initial and late blooming phases. Irrespective of blooming phases, the diversity of floral visitors was maximum on thrum morph as compared to pin morph. Among the dominant bee floral visitors, foraging rate of A. cerana was highest during maximum blooming phase. The foraging duration of A. florea for collection of nectar and pollen from pin and thrum morphs was highest among the major bee floral visitors recorded during maximum bloom phase. Effective pollination requires the peak foraging activity of dominant bee species during the maximum bloom phase.
Le couplage phosphore‐phosphore dans l'adenosine di‐ et triphosphate
Authors: Ellenberger M. , Brehamet L. , Villemin M. , Toma F.
Published: July 2002

The pH dependence of spin‐spin coupling constants J
P‐O‐P of ADP and ATP has been determined from the phosphorus NMR spectra at 0°. The variation curves have been interpreted as titration curves. These give different pK values. Comparison with the tripolyphosphate shows the existence of triphosphate chain structural deformation in the nucleotides.
Liaison entre histones et RNA. Action des proteines acides de la chromatine sur cette liaison
Authors: Dastugue B. , Tichonicky L. , Hanoune J. , Kruh J.
Published: July 2002

Histone is able to associate with radioactive RNA to form a complex which is retained on a millipore filter; 500 μg of histone F1 from bone marrow is able to combine with 100 μg of RNA. Chromatin acidic proteins reduce this association up to 50%. The binding between RNA and histone does not occur in the presence of urea and NaCl.
Vergleichende analyse der gegen rinderproinsulin und rinderinsulin gebildeten antikörper
Authors: Kerp L. , Steinhilber S. , Schmidt D.D.
Published: July 2002

Antisera to proinsulin contained equal amounts of high affinity binding sites specific for the C‐chain and for the insulin part of the molecule. After absorption of the insulin‐specific antibodies these sera can be used for the immunoassay of proinsulin.
Mutanten des hüllproteins (b‐protein) des bakteriophagen fd
Authors: Braunitzer G. , Braig S. , Krug F. , Hobom G.
Published: July 2002

The amino acid analyses of the mutant coat proteins (B‐proteins) show significant differences in comparison with the amino acid analyses of wild type coat protein.
Spin trapping evidence for free radical oxidants of aminopyrine in the metmyoglobin—cumene hydroperoxide system
Authors: Griffin Brenda Walker , Ting Patrick L.
Published: July 2002

Preliminary accounts of this work were presented at the American Chemical Society Southeast—Southwest Regional Meeting, October 29–31, 1975, Memphis, TN and at the American Chemical Society Southwest Regional Meeting, December 5–7, 1977, Little Rock, AR
Photoaffinity labeling of chloroplast cytochrome b6‐f complex by an inhibitor azido‐derivative
Authors: Oettmeier Walter , Masson Klaus , Olschewski Ellen
Published: July 2002

The photoaffinity label 2‐azido‐2′,4,4′‐trinitro‐6‐sec.butyldiphenylether inhibits photosynthetic electron transport in the thylakoid membrane as well as plastohydroquinone‐plastocyanin‐oxidoreductase activity in the isolated chloroplast cytochrome b
6‐f complex. In the latter, the 14C‐labeled inhibitor upon UV‐irradiation binds covalently only to the cytochrome b
6 and the Rieske Fe‐S peptide subunit.
A large cathepsin D‐derived fragment from the central part of the fibronectin subunit chains
Authors: Richter H. , Hörmann H.
Published: July 2002

A mild cathepsin D digest of fibronectin only contained single‐chain peptides of 200, 140 and 70 kDa and double‐chain fragments of about 300 and 140 kDa containing the C‐terminal disulfide link. Among the single‐chain fragments the 200 kDa peptide was a precursor of the 140 kDa and 70 kDa peptides. The latter was correlated to the N‐terminal and the former to the central region of the fibronectin subunit chains.
Effect of starvation on the N‐acetylglutamate system of rat liver
Authors: Gomez M. , Jordá A. , Cabo J. , Grisolía S.
Published: July 2002

Rats fasted for 3 and 6 days showed an increase in the activity, per g of liver but not per total liver, of the mitochondrial urea cycle enzymes, carbamylphopshate synthetase and ornithine transcarbamylase. The activity of N‐acetylglutamate synthetase, both per g and per total liver, increased by the third day and then decreased on the sixth day of fasting. The cytosolic enzyme N‐acetyldeacylase showed the same general pattern as the N‐acetylglutamate synthetase except that the relative proportion of synthetase over deacylase was higher at the third day of starvation. The N‐acetylglutamate level/g liver increases in relation to the number of days of fasting.
Subcellular distribution of abnormal proteins in rabbit reticulocytes
Authors: Daniels R.S. , McKay M.J. , Atkinson E.M. , Hipkiss A.R.
Published: July 2002

Inhibitors of ATP synthesis (cyanide, dinitrophenol, fluoride) inhibited proteolysis of pulse‐labelled abnormal proteins in rabbit reticulocytes and caused an accumulation of the aberrant polypeptides in the cell debris fraction in a manner analogous to phenylhydrazine‐induced Heinz bodies. When the reticulocytes were separated into age‐groups by sedimentation through discontinuous gradients of bovine serum albumin, the ability of the cells to degrade puromycin peptides decreased with increasing cellular maturity and, in the more mature cells, up to 40% of the labelled abnormal polypeptide remained associated with the cell debris fraction at the end of the chase period. It is suggested that the association of the abnormal polypeptide with the cell debris fraction is a consequence of a maturation‐induced loss, or an inhibitor‐induced inactivation of the cellular proteolytic activity.
Clathrin‐associated proteins contain bound nucleotide
Authors: Schook W.J. , Andrés A. , Puszkin S.
Published: July 2002

Clathrin‐associated proteins purifies from bovine brain exhibited an ultraviolet spectrum with absorbance maximum at 256 nm and were found to contain tightly bound nucleotide. This nucleotide was identified as AMP and/or ADP by thin‐layer and high‐performance liquid chromatographic analyses. The phosphorylation state of the bound nucleotide varied with storage conditions, suggesting that exchange with ATP might occur while a molar ratio of two nucleotides per protein molecule is maintained. This nucleotide binding site may play a role in the functions of clathrin‐associated proteins.
Fibre diffraction of lithium DNA shows structural variability and deviation from a regular helical structure for the B‐form
Authors: Dutta Santanu , Parrack Pradip K. , Sasisekharan V.
Published: July 2002

Recently, reports have appeared which show structural variations in B‐DNA and indicate deviations from a uniform helical structure. We report for the first time that these indications are also present in the B‐form fibre diffraction patterns for the lithium salt of natural DNA. We have used an improved method of controlling the salt concentration in the fibres. Our results are based on the appearance and disappearance of meridional reflections on different layer lines depending upon the salt.
31P‐nuclear magnetic resonance studies of intact plasmodia of Physarum polycephalum
Authors: Kohama Kazuhiro , Tanokura Masaru , Yamada Kazuhiro
Published: July 2002

31P‐nuclear magnetic resonance spectra were obtained from intact plasmodial cells of Physarum polycephalum, where cytoplasmic streaming is generated by actin‐myosin‐ATP interaction. Several peaks were resolved and identified. They included ATP, ADP, orthophosphate and polyphosphates. Peaks for phosphocreatine, phosphoarginine or AMP were not detected. The intracellular pH and concentrations of ATP and free Mg2+ were estimated to be pH 6.9, 0.2–0.5 mM, and about 1 mM, respectively.
The amino acid sequences of the α1 and α2 subunits of the isolectins from seeds of Lathyrusochrus (L) DC
Authors: Richardson M. , Rougé P. , Sousa-Cavada B. , Yarwood A.
Published: July 2002

Lathyrus ochrus isoelectin
α Subunit
Amino acid sequence
Homology
Legume lectin
Solution conformation and electrostatic potential distribution of prostaglandins and thromboxanes and their relation to specificity
Authors: Kalia A. , Kothekar V.
Published: July 2002

Prostaglandin
Thromboxane
Solution conformation
Electrostatic potential
Microsomal membranes contain phosphatidylcholine that equilibrates across the bilayer, and phosphatidylcholine that does not
Authors: Hutson Julie L. , Higgins Joan A. , Wirtz K.W.A.
Published: July 2002

Rat liver microsome
Asymmetry
Phosphatidylcholine
Phospholipase C
Phosphatidylcholine exchange protein
Phosphatidylcholine pool
Activation and stabilization of asparaginase by anti‐asparaginase IgG and its Fab
Authors: Yoshimoto T. , Takahashi K. , Ajima A. , Matsushima A. , Saito Y. , Tamaura Y. , Inada Y.
Published: July 2002

Asparaginase
2‐Hydroxy‐5‐nitrobenzyl bromide
Anit‐asparaginase IgG
Acylated fibronectin: a new type of posttranslational modification of cellular fibronectin
Authors: Lange-Mutschler Jutta
Published: July 2002

Fibronectin
Posttranslational modification
Protein acylation
Extracellular matrix
Inhibitory effect of 12‐O‐tetradecanoylphorbol 13‐acetate on acid secretion by rat stomach in vivo
Authors: Shaw G.P. , Hanson P.J.
Published: July 2002

Gastric acid secretion
Phorbol ester
(Stomach)
Protein kinase C
Chemical crosslinking of different forms of the simian virus 40 large T antigen using bifunctional reagents
Authors: Dietrich Jean Bernard
Published: July 2002

SV40
Large T antigen
Crosslinking
Oligomer
DNA
Increased sensitivity of fat cell adenylate cyclase to stimulatory agonists during fasting is not related to impaired inhibitory coupling system
Authors: Lacasa Daniéle , Agli Brigitte , Giudicelli Yves
Published: July 2002

In rat adipocytes, inhibition of the forskolin‐stimulated cyclic AMP response by nicotinic acid and N
6‐phenylisopropyladenosine was unaltered by a 72 h fasting. Under assay conditions favouring inhibition, basal and forskolin‐stimulated adenylate cyclase responses to inhibition by GTP and nicotinic acid were also unimpaired by fasting. Under the same conditions, however, low GTP concentrations elicited a clear activatory effect in membranes from fasted but not from fed rats. Fasting failed to alter the incorporation of [32P]ADP ribose into the αi‐subunit of Ni and the attenuation of nicotinic acid inhibitory action that are both induced by pertussis toxin. These results, demonstrating unimpaired inhibitory control of adenylate cyclase in starved rat adipocytes, suggest that the permissive effect of fasting on the action of stimulatory receptor agonists in fat cells reflects a specific increase in the activity of the adenylate cyclase stimulatory coupling system.
Fast abortive initiation of uvrA promoter in a supercoiled plasmid studied by stopped‐flow techniques
Authors: Bertrand-Burggraf E. , Ling C. , Schnarr M. , Lefèvre J.F. , Pouyet J. , Daune M.
Published: July 2002

In order to follow the fast kinetics of abortive initiation (lag time from 1 ms to 10 s), we have built a stopped‐flow apparatus equipped for fluorescence detection. The small volume used for each assay (35 μl), and the short dead time (∼0.5 ms) are the essential advantages of this apparatus. Supercoiling of DNA affects considerably the initiation of transcription from the uvrA promoter. It decreases the lag time due to the isomerisation process 3‐fold. Nevertheless, it does not change significantly the product K
B
k
2, which is indicative of promoter strength and shows that uvrA is an ‘association‐limited’ promoter. The presence of the LexA repressor increases the lag time considerably. At least for small RNA polymerase concentrations this increase is stronger for supercoiled than for linearized DNA.
Theoretical study on binding of Hoechst 33258 with oligonucleotides
Authors: Gopalakrishna Kovvali , Kalia Anita , Royyuru Ajay K. , Atreyi Mrigank M. , Rao M.V.R. , Kothekar V.
Published: July 2002

This gives desired curvature to the molecule which is stabilised by intermolecular forces.
Predicted structure of tail‐fiber proteins of T‐even type phages
Authors: Riede Isolde , Schwarz Heinz , Jähnig Fritz
Published: July 2002

The sequences of the tail fiber protein 36 of the phages T4, T2, K3, and Ox2 were analyzed for homologies and for folding patterns using structure prediction methods. No repeating motif was found. A model for the fiber structure is proposed in which β‐strands of about 6 amino acids are separated by turns. In the β‐strand, hydrophobic amino acids are found alternating with hydrophilic ones. Such amphipathic β‐strands can be stabilized by dimer formation. The dimerization occurs in a parallel fashion so that both N‐termini are at one end of the dimer. This structure represents a rigid fiber. Our model is consistent with electron microscopic data and electron diffraction patterns for the T4 tail fiber. The observation that all fiber components are found as dimers supports our model. Sequences of the receptor recognition proteins 38 of T‐even type phages reveal an architecture different from the architecture of the fiber proteins 36 and 37 of these phages.
Isolation of cDNAs coding for epitopes shared by microtubule‐associated proteins and neurofibrillary tangles in Alzheimer's disease
Authors: Brion Jean-Pierre , Cheetham Michael E. , Robinson Philip A. , Couck Anne-Marie , Anderton Brian H.
Published: July 2002

5 cross‐hybridizing cDNA clones of sizes 2.2 (3 cDNAs), 1.3 and 0.8 kb corresponding to tau microtubule‐associated protein have been isolated from a rat brain λgt11 expression library. Antibodies affinity‐purified using the fusion protein encoded by the cDNAs were observed to label tau polypeptides on Western blots and Alzheimer's neurofibrillary tangles.
Primary structure of bovine cerebellum GTP‐binding protein G39 and its effect on the adenylate cyclase system
Authors: Ovchinnikov Yu.A. , Slepak V.Z. , Pronin A.N. , Shlensky A.B. , Levina N.B. , Voeikov V.L. , Lipkin V.M.
Published: July 2002

The primary structure of bovine cerebellum GTP‐binding protein α‐subunit, protein G39 was determined by parallel analysis of the protein amino acid sequence and the corresponding cDNA nucleotide sequence. The protein consists of 354 amino acid residues and has a molecular mass of 40064 Da. High homology between G39 and other G‐proteins, especially rat brain Go was shown. An assumption is made that certain brain adenylate cyclase system properties are determined by the presence of G39.
Activation of metallothionein expression is potentiated by DNA sequences present in the herpes simplex virus thymidine kinase gene
Authors: Lewis John A. , di Girolamo Adele Bendicenti
Published: July 2002

A mouse cell line (Ltk— aprt—) which is resistant to the anti‐viral effects of interferon also has a reduced ability to synthesize metallothionein on exposure to cadmium. Like the ability to respond to interferon, cadmium‐induced metallothionein synthesis is restored to wild‐type levels in clones obtained by introducing a thymidine kinase gene into Ltk— aprt— cells. Transfection of other genes does not have such an effect. Since metallothionein expression is also activated by interferon the results suggest that the regulation of several genes which are responsive to interferon can be modulated by specific sequences present in the Herpes virus thymidine kinase gene.
The GATATC‐modification enzyme EcoRV is closely related to the GATC‐recognizing methyltransferases DpnII and dam from E. coli and phage T4
Authors: Lauster Roland , Kriebardis Anastasios , Guschlbauer Wilhelm
Published: July 2002

The amino acid sequence of EcoRV DNA methyltransferase which methylates the amino group of the 5′‐adenine residue of the target sequence GATATC has been found to be closely related to that of three other adenine methyltransferases, DpnII, dam and damT4, the target sequence of which is GATC. Despite large differences on the DNA level, the four sequences show four blocks of homologies. One of these blocks has the sequence DVYXDPPY and is found with little modification in numerous other DNA inethyltransferases. It is speculated that it could be the binding site of the methyl donor, S‐adenosylmethionine. On the other hand, the identification of a DNA‐binding region is more tenuous. As expected, no analogies with (dimeric) repressors and cro proteins which have the characteristic helix‐turn‐helix motif have been observed.
Electric field effect on absorption spectra of reaction centers of Rb. sphaeroides and Rps. viridis
Authors: Braun H.P. , Michel-Beyerle M.E. , Breton J. , Buchanan S. , Michel H.
Published: July 2002

Comparison of the Stark effect on the Qy transitions of the pigments in reaction centers of Rb. sphaeroides and Rps. viridis at 77 K shows great similarity in the long‐wavelength absorption of the bacteriochlorophyll dimer but differs significantly in the absorption region of the accessory bacteriochlorophylls and bacteriopheophytins.
The interaction of ferredoxin‐linked sulfite reductase with ferredoxin
Authors: Hirasawa Masakazu , Boyer J.Milton , Gray Kevin A. , Davis Danny J. , Knaff David B.
Published: July 2002

Spinach sulfite reductase has been shown to co‐migrate during gel filtration chromatography at low ionic strength with spinach ferredoxin. No co‐migration was observed at high ionic strength. These results indicate that the two proteins form a high‐affinity, electrostatically stabilized complex, as had previously been demonstrated for three other ferredoxin‐dependent, plant enzymes. Modification of 3–4 ferredoxin carboxyl groups had little detectable effect on the ferredoxin‐sulfite reductase interaction.
Direct evidence for the participation of pyruvate in N‐hydroxylation of lysine
Authors: Szczepan Edward W. , Kaller Damon , Honek John F. , Viswanatha Thammaiah
Published: July 2002

The contribution of pyruvate to the formation of N
6‐acetyl‐N
6‐hydroxylysine by a cell‐free system of Aerobacter aerogenes 62‐1 involved in the production of the dihydroxamate siderophore, aerobactin, has been assessed by a study of the influence of its analogs as well as of inhibitors of thiamine pyrophosphate‐dependent decarboxylation reactions. These studies have provided unequivocal evidence for pyruvate functioning not only as a source of reducing equivalents in the initial step of N‐hydroxylation of lysine but also as a precursor of the acetyl moiety in the subsequent conversion of the N‐hydroxy amino to its N
6‐acetyl derivative.
Mutual inactivation of valinomycin and protonophores by complex formation in liposomal membranes
Authors: Krishnamoorthy G.
Published: July 2002

The simultaneous presence of a protonophore [3,5‐di(tert‐butyl)‐4‐hydroxybenzylidenemalononitrile or carbonyl cyanide m‐chlorophenylhydrazone] and valinomycin in a liposome suspension results in time‐dependent inactivation of ion transport by both the protonophore and valinomycin. Correlation of the inactivation with spectrophotometric observations on the formation of a complex between the protonophore and valinomycin strongly suggests that the complex observed has no (or very low) activity for the transport of either H+ or K+. The stoichiometry of valinomycin and the protonophore in the inactive complex is shown to be 1:1.
The partial purification of a factor from Dunaliella salina that causes the rapid in situ inactivation of light‐activated chloroplast coupling factor 1 (CF1)
Authors: Selman-Reimer Susanne , Selman Bruce R.
Published: July 2002

A factor having the expected properties of the in vivo oxidant responsible for inactivating the in vivo light‐activated chloroplast coupling factor 1 (CF1) has been partially purified from cell‐free extracts of Dunaliella salina. This factor is highly polar, weakly acidic, and relatively temperature stable. The ability of this factor to inactivate light‐activated CF1 is prevented if it is pretreated with reductants such as dithiothreitol. The factor has virtually no effect on the ethanol‐induced, Mg2+ ‐dependent ATPase activity of the isolated CF1.
Antigenic determinants synthesized in a library of randomly cloned fragments of the HIV‐1 genome
Authors: Mikhailov M.V. , Vasilyev A.L. , Nikolayeva I.A. , Arsenyan S.G. , Sverdlov E.D.
Published: July 2002

A DNA expression library of randomly selected fragments of the HIV‐1 genome was constructed and used to search for antigenic determinants. A large segment of the HIV‐1 provirus was sonicated, and 150–250 bp DNA fragments were cloned in a system of expression vectors developed to obtain high yields of recombinant proteins in Escherichia coli. The expressed library was immunoscreened with sera of AIDS patients. Eleven identified immunoreactive clones were found to correspond to already known and new antigenic regions of HIV‐1 proteins gp41, p24, and reverse transcriptase.
Hoogsteen versus Watson‐Crick A‐T basepairing in DNA complexes of a new group of ‘quinomycin‐like’ antibiotics
Authors: Searle Mark S. , Wickham Geoffrey
Published: July 2002

The interaction of a new group of ‘quinomycin‐like’ antibiotics with the DNA duplexes d(ACGT)2 and d(GACGTC)2 has been investigated in solution by 1H NMR spectroscopy. By monitoring the intensity of intranucleotide base H6/H8 to deoxyribose H1'NOE cross‐peaks we conclude that the terminal A‐T basepairs flanking the CG bisintercalation site in the d(ACGT)2 complex adopt the Hoogsteen bonding scheme, with the purine base in a syn conformation. By comparison in the d(GACGTC)2 complex all glycosidic bond angles are anti, consistent with a preferred Watson‐Crick basepairing scheme. Both DNA duplexes appear to be significantly unwound compared with the ligand‐free DNAs. The data illustrate the influence of helical constraints on the stability of the Hoogsteen bonding scheme adjacent to the drug binding sites.
Inhibition of endothelin‐mediated topoisomerase I activation by pertussis toxin
Authors: Nambi Ponnal , Wu Hsiao-Ling , Woessner Richard D. , Mattern Michael R.
Published: July 2002

Cultured rat mesangial cells contain high affinity endothelin (ET) receptors at high densities. Exposure of these cells to ET resulted in a transient activation of topoisomerase I extractable activity, which reached its maximum value at approximately 2 min and returned to basal value after approximately 10 min of treatment. The activation of this enzyme was dependent upon the concentration of ET added. Incubation of the cells with pertussis toxin inhibited ET‐induced increases in topoisomerase I activity in a concentration‐dependent manner, suggesting the involvement of pertussis toxin‐sensitive GTP‐binding protein in ET‐mediated action. Endothelin had no detectable effect upon extractable topoisomerase II activity.
Proteolytic activity of plum pox virus—tobacco etch virus chimeric NIa proteases
Authors: Garcia Juan Antonio , Lain Sonia
Published: July 2002

Plasmids encoding chimeric NIa‐type proteases made of sequences from the polyviruses plum pox virus (PPV) and tobacco etch virus (TEV) have been constructed. Their proteolytic activity on the large nuclear inclusion protein (NIa)‐capsid protein (CP) junction of each virus was assayed in Escherichia coli cells. The amino half of the protease seemed to be involved neither in the enzymatic catalysis nor in substrate recognition. In spite of the large homology among the PPV and TEV NIa‐type proteases, the exchange of fragments from the carboxyl halves of the molecules usually caused a drastic decrease in the enzymatic activity. Inactive chimeric proteases did not interfere with cleavage by PPV wild type protease expressed from a second plasmid. The results suggest that the recognition and catalytic sites of the NIa proteases are closely interlinked and, although residues relevant for the correct interaction with the substrate could be present in other parts of the protein, a main determinant for substrate specificity should lie in a region situated, approximately, between positions 30 and 90 from the carboxyl end. This region includes the conserved His at position 360 of PPV or 355 of TEV, which has been postulated to interact with the Gin at position −1 of the cleavage sites.
Inhibition of Na,K‐ATPase by a new ATP analog, adenosine‐5‐N′‐(2,4‐dinitro‐5‐fluorophenyl)phosphohydrazide
Authors: Lopina Olga , Skačkova Dagmar , Buranova Ludmila , Khropov Yuri
Published: July 2002

A new ATP analog, adenosine‐5‐N′‐(2,4‐dinitro‐5‐fluorophenyl) phosphohydrazide (DNPH‐AMP), has been synthesized, which is an irreversible inhibitor of Na,K‐ATPase. Interaction of the analog with the enzyme in the presence or K+ is describe by the scheme:, and corresponding kinetic constant k3
and Ki
are found equal to 2.5 min−1 and 1.6 mM. In the presence of Na+ the time course enzyme inactivation by DNPH‐AMP is a biphasic curve in the semilogarithmic plot, The k3
and Ki
values calculated for this case according to Fritzsch (Fritzch (1985) J. Theor. biol, 117 397) are equal to 2.45 min−1 and 2.5 mM, respectively. ATP transforms the K* ‐type or Na,K‐ATPase inactivation into the one that takes place in the presence of Na*.
Superoxide dismutase activation in thyroid and suppression in adrenal Novel pituitary regulatory routes
Authors: Verma Saguna , Pradeep Kumar G. , Laloraya Malini , Nivsarkar Manish , Singh Apurna
Published: July 2002

This study reports that administration of TSH in young female mice results in a concomittant augmentation of SOD activity in the thyroid gland. A strong thyroid‐adrenal interdependence was also evident in the form of a marked loss of SOD activity in the adrenal gland in response to TSH administration. Very recently SOD/O.−
2 system had been identified as a potent H2O2 generator which provides substrate for the action of key enzyme in thyroxine and progesterone biosynthesis, viz, the peroxidase. Thus, these results strongly suggest that trophic hormones tonically stimulate hormone biosynthesis by modulating activation/suppression of specific enzymes, which could be the basis of the tuning sequence.
The occurance of carbonyl reduction in continuous cell lines emphasizes the essentiality of this metabolic pathway
Authors: Gebel Thomas , Maser Edmund , Netter Karl J.
Published: July 2002

Using the ketone compound metyrapone (MPON) as a substrate for carbonyl reduction it has been verified for the first time that various permanent cell lines in culture express carbonyl reducing activity. This is even true for the dedifferentiated and fibroblasloid cell line V79, emphasizing the essentiality of this metabolic pathway. MPON reducing enzyme activities are located in the endoplasmic reticulum as well as in the cytoplasm of the cells. Compared to MPON‐reductase in rat liver microsomes, no immunological homology to microsomal C2REV7 rat liver hepatoma cell MPON‐reductase could be detected, indicating differences in antigenic determinants between the enzymes of the solid organ and respective cells in continuous culture.
Cloning of human α1(X) collagen DNA and localization of the COL10A1 gene to the q21–q22 region of human chromosome 6
Authors: Apte Suneel , Mattei Marie-Genevieve , Olsen Bjorn R.
Published: July 2002

With consensus primers based upon the nucleotide sequence of the chicken α1(X) collagen gene, we have used PCR with human genomic DNA as template to isolate a 289 bp fragment coding for part of the carboxyl non‐triple helical domain of the human α1(X) gene. We have demonstrated the presence of the sequence of the PCR clone within the human genome by partial sequence analysis of a 1 kb HindIII genomic DNA fragment that hybridized with the PCR clone. Furthermore, using the PCR clone as a probe for in situ hybridization of human metaphase chromosome spreads, and for Southern analysis of a panel of human—hamster somatic cell hybrid DNAs, we have assigned he locus for the α1(X) gene to the q‐21–q22 region of human chromosome 6.
Pre‐translational regulation by glucocorticoid of fatty acid and phosphatidylcholine synthesis in type II cells from fetal rat lung
Authors: Batenburg J.J. , Elfring R.H.
Published: July 2002

Exposure to fibroblast‐conditioned cortisol‐containing medium increased fatty acid synthase activity and fatty acid synthase, acetyl‐CoA carboxylase and ATP citrate lyase mRNA abundance in fetal type II alveolar epithelial cells. Both fibroblast conditioning and cortisol in the medium were required for maximal effect on the mRNA levels, indicating involvement of mesenchymal—epithelial interaction in the cortisol effects. The observed effects provide evidence for an earlier hypothesis that increased activity of CTP:phosphocholine cytidylyltransferase in lung tissue caused by glucocorticoid is due to increased fatty acid synthesis. However, evidence suggesting pre‐translational regulation of the enzyme by glucocorticoid was also found.
Characterization of carbohydrate chains of C1‐inhibitor and of desialylated C1‐inhibitor
Authors: Schoenberger Oeyvind L.
Published: July 2002

Carbohydrate chains of C1‐inhibitor were identified with a binding assay using different lectins. Lectins from Sambucus nigra (SNA) and Maackia amurensis (MAA) that are specific for sialic acids bound to C1‐inhibitor. Lectin from Datura strantonium (DSA) reacted also with the inhibitor indicating complex and hybrid sugar structures. C1‐inhibitor was enzymatically desialylated and reexamined for lectin binding. SNA and MAA did not react anymore, but in addition to DSA, peanut agglutinin, which can bind to carbohydrate chains after sialic acids are removed, bound to desialylated C1‐inhibitor. C1‐inhibitor contains about 30 sialic acid residues per molecule. SDS‐polyacrylamide gel electrophoresis showed that desialylated C1‐inhibitor had a faster mobility than native C1‐inhibitor. The N‐terminal sequence of desialylated C1‐inhibitor was the same as of native C1‐inhibitor and no change in the inhibition of human plasma kallikrein was observed.
Verification of the interaction between peptide T and CD4 using surface plasmon resonance
Authors: Ramsdale Tracie E. , Andrews Peter R. , Nice Edouard C.
Published: July 2002

Peptide T is currently in phase II clinical trials for the treatment of AIDS‐associated dementia. Its putative mode of action is inhibition of binding of the HIV envelope protein (gp120) to its cellular receptor (CD4), thus preventing viral infectivity and gp120‐induced neuronal toxicity. However, a number of reports have appeared in the literature which have failed to observe any inhibitory activity of Peptide T on CD4‐gp120 binding, thus casting doubt on this hypothesis. This study uses a novel biosensor technique to demonstrate that Peptide T does bind to CD4 and that this binding can be specifically inhibited by an anti‐CD4 monoclonal antibody. A detailed analysis of the kinetics of the interaction is presented.
Escherichia coli single‐stranded DNA‐binding protein alters the structure of intramolecular triplexes in plasmids
Authors: Klysik Jan , Shimizu Mitsuhiro
Published: July 2002

The ability of the Escherichia coli single‐stranded DNA‐binding protein (SSB) to recognize structural features associated with intramolecular triplex formation in oligopurine · oligopyrimidine (pur · pyr) inserts in recombinant plasmids was evaluated. The SSB protein binds to supercoiled plasmids and causes a site‐preferential increase in OsO4 reactivity of the pyrimidine strand involved in the formation of the Hy‐3 isomer of the triplex structure. The E. coli RecA protein showed no reaction with triplexes in similar studies. This behavior is consistent with SSB‐mediated unpairing of the H‐DNA‐forming region.
A distal region of the CALC‐1 gene is necessary for regulated alternative splicing
Authors: Horn D.A. , Latchman D.S.
Published: July 2002

The CALC‐1 gene exhibits tissue specific alternative splicing with exons 1–4 being spliced to produce the calcitonin mRNA in thyroid C cells and exons 1–3 and 5–6 being joined to produce the CGRP mRNA in neuronal cells. Previous studies have identified an element in intron 3 within the alternatively spliced region which is critical for this effect to occur. We show here that deletion of sequences downstream of the alternatively spliced region also disrupts the tissue specific pattern of alternative splicing. The manner in which these sequences act is discussed.
Chemical crosslinking studies of the isolated light‐harvesting B800‐850 complex of Chromatium minutissimum
Authors: Moskalenko Andrey A. , Toropygina Olga A.
Published: July 2002

The spatial relationship of polypeptides comprising the light‐harvesting B800‐850 complex of Chromatium minutissimum has been studied by means of chemical crosslinking of the isolated complex with cleavable, 1.2 nm‐long dithiobis(succinimidyl propionate). The samples were analyzed by different types of electrophoresis and spectrophotometrically. No difference was shown between crosslinking of the B800‐850 complex either solubilized or incorporated into proteoliposomes. It was found that two main polypeptides form only one type of heterodimer. The crosslinked complex was more thermostable. This crosslinkage restricted the conformational transitions causing the shift of the long wavelength band in the near infrared region. A structure of the complex is discussed.
Distribution of non‐class‐III β‐tubulin isoforms in neuronal and non‐neuronal cells
Authors: Linhartová Irena , Dráberová Eduarda , Viklický Vladimír , Dráber Pavel
Published: July 2002

β‐Tubulin isoforms in brain tissues and in cell lines were analyzed by high‐resolution isoelectric focusing in combination with monoclonal antibodies. Post‐translational modifications of brain non‐class‐III β‐tubulin isoforms were found in phylogenetically distant species ranging from pig to carp. Less extensive modifications were also observed in Neuro‐2a, HeLa and 3T3 cells, where most acidic isoforms were glutamylated, while the basic, most abundant isoforms were not. The data suggest post‐translational modification of non‐class‐III β‐tubulin isoforms in neuronal as well as in non‐neuronal cells. Such modification might modulate interaction of tubulin isoforms with microtubule‐associated proteins.
Regulation of adenylyl cyclase from Blastocladiella emersonii by guanine nucleotides
Authors: Terenzi Hernán , da Costa Maia José Carlos
Published: July 2002

GTPγS stimulates adenylyl cyclase in particulate fractions of Blastocladiella emersonii zoospores. Cholera toxin catalyses the ADP‐ribosylation of a membrane protein of a molecular weight (46,000) similar to that of the α subunit of Gs
found in vertebrate cells. A membrane protein of 46 kDa can also be recognized in Western blots by an antipeptide antiserum (RM/1) raised against the C‐terminus of Gα
s
‐subunits. These results suggest that a G‐protein mediates the regulation of Blastocladiella adenylyl cyclase by guanine nucleotides.
A growth inhibitor implicated in the growth arrest of human fibroblasts
Authors: Macieira-Coelho A.
Published: July 2002

When quiescent human fibroblasts are induced to divide, the sugar composition of a growth inhibitory glycoprotein is modified. The kinetics of the incorporation of glucosamine in the growth inhibitor follows the kinetics of cell growth. It increases as cells approach quiescence and declines when cells initiate proliferation. The results suggest that the modification of the sugar composition of this glycoprotein is coupled with the variation of its inhibitory potential and this way to the initiation and the arrest of cell division.
Characterization of a recombinant proteinase 3, the autoantigen in Wegener's granulomatosis and its reactivity with anti‐neutrophil cytoplasmic autoantibodies
Authors: Witko-Sarsat Véronique , Halbwachs-Mecarelli Lise , Almeida Roque P. , Nusbaum Patrick , Melchior Maxine , Jamaleddine Ghassan , Lesavre Philippe , Descamps-Latscha Béatrice , Gabay Joëlle E.
Published: July 2002

Using the baculovirus/insect cells system, we have expressed a recombinant proteinase 3 (PR3) — the neutrophil‐derived serine protease autoantigen in Wegener's granulomatosis — as a glycosylated intracellular and membrane‐associated protein. Ollgosaccharides accounted for the difference in molecular weights between recombinant (34 kDa) and neutrophil‐PR3 (29 kDa). Whereas rabbit‐anti‐PR3 IgG recognized both recombinant and neutrophil‐derived PR3, autoantibodies from Wegener patient sera recognized only neutrophil‐derived PR3. Although oligosaccharides were not involved in PR3 epitope recognition, autoantibodies did not recognize the amino acid primary structure of recombinant PR3. Improper disulfide bond formation and/or lack of post‐translational events in insect cells, may affect the conformation of PR3, precluding its reactivity with sera from WG patients.
Growth pattern of the Indian fetus
Authors: Mathai M. , Thomas S. , Peedicayil A. , Regi A. , Jasper P. , Joseph R.
Published: July 2002

Objectives: To determine the pattern of intrauterine growth and the gestation at birth of Indian fetuses. Method: One hundred twenty consecutive women who had reliable menstrual histories, low‐risk pregnancies and who were booked for delivery at the Christian Medical College Hospital, Vellore, before 20 weeks' gestation were recruited to the study. Ultrasound fetal biometry was carried out at 4‐weekly intervals from 20 weeks and at weekly intervals after 36 weeks until delivery. Results: Growth patterns of fetal biparietal diameter and femur length were comparable to those reported in Western populations. However there was a lag in growth of abdominal circumference (AC) after 28 weeks in comparison with that reported in Western populations. The median gestation at delivery following spontaneous labor was 39 weeks. No association was observed between rate of growth of AC and gestation at birth. Conclusion: Slowing of growth of the fetal AC after 28 weeks and a shorter length of gestation result in the birth of smaller babies in this ethnic group. The implications of these findings are discussed.
Assembly of the CD8α/p56lck protein complex in stably expressing rat epithelial cells
Authors: Pascale M.C. , Remondelli P. , Leone A. , Bonatti S.
Published: July 2002

We have previously characterized the biogenesis of the human CD8α protein expressed in rat epithelial cells. We now describe the biosynthesis, post‐translational maturation and hetero‐oligomeric assembly of the human CD8α/p56
lck
protein complex in stable transfectants obtained from the same cell line. There were no differences in the myristilation of p56
lck
, or in the dimerization, O‐glycosylation and transport to the plasma membrane of CD8α, between cells expressing either one or both proteins. In the doubly expressing cells, dimeric forms of CD8α established hetero‐oligomeric complexes with p56
lck
, as revealed by co‐immunoprecipitation assays performed with anti‐CD8α antibody. Moreover, p56
lck
bound in these hetero‐oligomeric complexes was endowed with auto‐ and hetero‐phosphorylating activity. The present study shows that: (1) the newly synthesized p56
lck
binds rapidly to CD8α and most of the p56
lck
is bound to CD8α at steady state; (2) CD8α/p56
lck
protein complexes are formed at internal membranes as well as at the plasma membrane; and (3) about 50% of complexed p56
lck
reaches the cell surface.
Overexpression of a dominant negative CREB protein in HT‐1080 cells selectively disrupts plasminogen activator inhibitor type 2 but not tissue‐type plasminogen activator gene expression
Authors: Costa Magdaline , Shen Yang , Medcalf Robert L
Published: July 2002

The tissue‐type plasminogen activator (t‐PA) and plasminogen activator inhibitor type 2 (PAI‐2) genes are differentially regulated by 12‐phorbol 13‐myristate acetate (PMA) in HT‐1080 fibrosarcoma cells. PMA transcriptionally down‐regulates the t‐PA gene in HT‐1080 cells, while the PAI‐2 gene is simultaneously induced by this agonist. The t‐PA and PAI‐2 gene promoters harbour a cAMP‐response element (CRE) which influences the expression of both genes. We have compared the binding activity of nuclear factors that recognise these CRE sites. We show that CREB (CRE binding protein) recognises each CRE and that the degree of constitutive Ser119‐phosphorylated t‐PA CRE‐bound CREB was greater than for PAI‐2 CRE bound CREB. Stable transfection of HT‐1080 cells with a plasmid containing a CREB that could not be phosphorylated on Ser119 (pCI‐CREBala119) did not influence PMA‐mediated suppression of t‐PA mRNA, but markedly impaired PMA‐mediated induction of PAI‐2 mRNA. Our results demonstrate that the Ser119 residue of CREB plays a crucial role in PMA‐mediated induction of PAI‐2 gene expression, whereas PMA‐mediated suppression of t‐PA in HT‐1080 cells requires a different process.
Structure determination and by‐product profile of the NK2 receptor antagonist nepadutant, a bicyclic glycopeptide
Authors: Weißhoff Hardy , Nagel Thomas , Hänsicke Andre , Zschunke Adolf , Mügge Clemens
Published: July 2002

We have synthesized and fully characterized the NK2 receptor antagonist nepadutant and its by‐products using nuclear magnetic resonance (NMR) and restrained molecular dynamics. The agent consists of an active bicyclic hexapeptide combined with a sugar residue. Analysis of the high‐performance liquid chromatogram and the mass spectroscopy spectra yields traces of three by‐products with the same molecular weight as the main product. The conformation of the molecules in the bicyclic hexapeptide segment, the active region, is well defined, whereas the sugar moiety is disordered. For the peptide region of nepadutant and all of its by‐products, the NMR observables can be described by a single backbone conformation, more specifically a βI, βII‐turn arrangement. The active dipeptide unit Trp–Phe occupies the i+1 and i+2 position of a βI‐turn. The by‐product profile is characterized by different forms of sugars which are caused mainly by isomerization in the process of ring opening.
Inhibition of phorbol ester‐stimulated phospholipase D activity by chronic tamoxifen treatment in breast cancer cells
Authors: Kiss Zoltan , Anderson Wayne H
Published: July 2002

We have shown that in an estrogen receptor‐negative multidrug‐resistant subline of MCF‐7 human breast carcinoma cells longer‐term (24 h), but not shorter‐term (30 min), treatments with clinically relevant (2–5 μM) concentrations of tamoxifen (TAM) inhibited phorbol ester‐stimulated phospholipase D (PLD) activity by 50–80%. TAM caused these inhibitory effects without inducing membrane translocation or down‐regulation of protein kinase C‐α, the major mediator of phorbol ester effects on PLD activation. The results raise the possibility that prolonged inhibition of the protein kinase C‐α‐regulated PLD system may contribute to the cytotoxic effects of tamoxifen in estrogen receptor‐negative breast cancer cells.
Isolation and characterization of the bioactive circulating human parathyroid hormone, hPTH‐1–37
Authors: Hock Dieter , Mägerlein Markus , Heine Gabi , Ochlich Peter P , Forssmann Wolf-Georg
Published: July 2002

The occurrence of hPTH‐1–37 as the native bioactive circulating form of PTH‐1–84 has now been obtained using a specific purification procedure for circulating parathyroid hormone, which involves a newly developed immunoenzymetric assay for N‐terminally intact hPTH. In combination with two different methods of mass spectrometry, the molecular weight of the isolated immunoreactive peptide was shown to be 4401 Da, which corresponds to hPTH‐1–37. Synthetic hPTH‐1–37 material was tested in the chick bioassay and produced a clear‐cut increase in serum calcium concentration. We conclude that hPTH‐1–37 is the native bioactive fragment of hPTH‐1–84 in circulation.
Crystallographic investigation of the dependence of calcium and phosphate ions for notexin
Authors: Westerlund Bengt , Saarinen Markku , Person Bertil , Ramaswamy S , Eaker David , Eklund Hans
Published: July 2002

© 1997 Federation of European Biochemical Societies.
Modifications of proteoglycans secreted into the growth medium by young and senescent human skin fibroblasts
Authors: Passi Alberto , Albertini Riccardo , Campagnari Francesco , De Luca Giancarlo
Published: July 2002

The properties of proteoglycans (PGs) secreted into the growth medium by normal young and senescent human skin fibroblasts (HFs) were investigated. In both cases, the incorporation per cell of radioactive precursors into total PGs was similar. The polysaccharide chains of PGs from young and senescent HFs were mainly represented by galactosaminoglycuronans and showed a similar range of size distribution. However, galactosaminoglycuronans of PGs secreted by senescent HFs had a lower content of unsulphated disaccharides and a lower proportion of d‐glucuronosyl residues. Moreover, senescent HFs released into the growth medium higher relative amounts of small PGs with chondroitin sulphate, dermatan sulphate chains, such as decorin.
The EGF‐like domain of chick acetylcholine receptor‐inducing activity (ARIA) contains its full biological activity
Authors: Yang J.F , Ng Y.P , Pun S , Ip N.Y , Tsim K.W.K
Published: July 2002

© 1997 Federation of European Biochemical Societies.