bluuebunny/crossref_metadata_2025 huggingface dataset:
Cyclophilin‐B is an abundant protein whose conformation is similar to cyclophilin‐A
Authors: Galat Andrzej , Bouet Françoise
Published: July 2002

Cyclophilin‐B (bCyP‐20) was isolated in a relatively high quantity from calf brain and spleen tissues consecutively applying weak cation exchange, chromatofocusing and strong cation exchange chromatographies. Edman degradation yielded the N‐terminal sequence NH2‐DEKKKGPKVTVK‐VYFDLRIGDEDIGRVVIGLFGKTVPKTVDNFVAL. Bovine cyclophilin‐B possesses the peptidylproline cis‐trans isomerase activity which is inhibited by nM concentrations of CsA. bCyP‐20 has a strong tendency to bind to cation exchangers including DNA and heparin. It could be released from DNA affinity column at concentrations of NaCl higher than 200 mM. Circular dichroism spectroscopy revealed that bovine cyclophilin‐A (bCyP‐18) and bCyP‐20 in aqueous solution have similar conformations.
Rapid and simple approach for the NMR resonance assignment of the carbohydrate chains of an intact glycoprotein Application of gradient‐enhanced natural abundance 1H‐13C HSQC and HSQC‐TOCSY to the α‐subunit of human chorionic gonadotropin
Authors: de Beer Tonny , van Zuylen Carol W.E.M. , Hård Karl , Boelens Rolf , Kaptein Robert , Kamerling Johannis P. , Vliegenthart Johannes F.G.
Published: July 2002

The structure assessment of an intact glycoprotein in solution requires an extensive assignment of the carbohydrate NMR resonances. However, assignment of homonuelear spectra is very complicated because of the severe overlap of protein and carbohydrate signals. Application of pulsed field gradients allowed high quality natural abundance 1H‐13C HSQC and HSQC‐TOCSY spectra to be recorded of the α‐subunit of human chorionic gonadotropin. Most carbohydrate 1H‐13C correlations appear in a distinct region between the aromatic region and the protein Cα‐Hα region. The enormous reduction in overlap led to fast and unambiguous assignment of the anomeric 1H‐13C correlations. Subsequently, correlations of the monosaccharide skeleton atoms were readily assigned in the HSQC‐TOCSY spectrum.
Autophosphorylation‐activated protein kinase inactivates the protein tyrosine phosphatase activity of protein phosphatase 2A
Authors: Damuni Zahi , Xiong Haishan , Li Mei
Published: July 2002

Phosphorylation of the catalytic subunit of protein phosphatase 2A (PP2A) on threonines with a distinct autophosphorylation‐activated protein kinase [Guo and Damuni (1993) Proc. Natl. Acad. Sci. USA 90, 2500–2504] inactivated the phosphatase with 32P‐labelled myelin basic protein prepared by incubation with the kinase domain of the epidermal growth factor receptor, the src‐family protein kinases p56lck and p60c‐src, myelin basic protein kinase‐1, or protamine kinase. Phosphoamino acid analysis demonstrated that the kinase domain of the epidermal growth factor receptor, p56lck and p60c‐src phosphorylated myelin basic protein on tyrosines, that the protamine kinase phosphorylated myelin basic protein on serines, and that myelin basic protein kinase‐1 phosphorylated myelin basic protein on threonines. The results demonstrate that the autophosphorylation‐activated protein kinase not only inactivates the protein serine/threonine phosphatase, but also the protein tyrosine phosphatase activity of PP2A. This autophosphorylation‐activated protein kinase‐mediated inactivation of PP2A may, in response to extracellular stimuli, not only contribute to the enhanced phosphorylation of cellular proteins on serines and threonines but also on tyrosines.
Inhibition of growth and cysteine proteinase activity of Staphylococcus aureus V8 by phosphorylated cystatin α in skin cornified envelope
Authors: Takahashi Masae , Tezuka Tadashi , Katunuma Nobuhiko
Published: July 2002

The activity of a cysteine proteinase purified from Staphylococcus aureus V8 (SAV8) was inhibited by phosphorylated cystatin α (P‐cystatin α) and by purified cornified envelope protein of newborn rat, a conjugated form of P‐cystatin α. Immunohistochemical analysis demonstrated a marked decrease in P‐cystatin α content in cornified envelope treated with sphingosine. The inhibition of papain activity by proteins from sphingosine‐treated skin was much weaker than that exerted by proteins from the untreated skin. The suppression of SAV8 colony formation inoculated on the sphingosine‐treated skin was examined. Colony formation on the sphingosine‐treated skin was enhanced compared to that on normal skin. These findings suggest that P‐cystatin α in the cornified envelope may have a bacteriostatic barrier function against bacterial infection, such as that with SAV8.
5‐Hydroxytryptamine affects turnover of polyphosphoinositides in maize and stimulates nitrate reductase in the absence of light
Authors: Chandok Meena R. , Sopory Sudhir K.
Published: July 2002

Incubation of etiolated maize leaves for 5 min in 5‐hydroxytryptamine increased phosphatidylinositol‐4,5‐bisphosphate levels but on longer incubation its level decreased and a corresponding increase in inositol‐trisphosphate was observed. The increase in phosphatidylinositol‐4,5‐bisphosphate by 5‐hydroxytryptamine was similar to that obtained after short irradiation of leaves with red light. Nitrate‐inducible and phytochrome‐stimulated enzyme nitrate reductase could be stimulated in darkness if the leaves were incubated in the presence of nitrate and 5‐hydroxytryptamine. These results indicate that one of the initial events in phytochrome‐mediated enzyme stimulation could be through the generation of ‘signals’ from the turnover of the phosphoinositide cycle.
Structure of leech derived tryptase inhibitor (LDTI‐C) in solution
Authors: Mühlhahn Peter , Czisch Michael , Morenweiser Robert , Habermann Bianca , Engh Richard A. , Sommerhoff Christian P. , Auerswald Ennes A. , Holak Tad A.
Published: July 2002

The three‐dimensional solution structure of the leech derived tryptase inhibitor form C (LDTI‐C), an inhibitor of 46 amino acids which contains 3 disulfide bridges, has been determined using 2D NMR spectroscopy. The 3D structure was determined on the basis of 262 interresidue interproton distance constraints derived from nuclear Overhauser enhancement measurements and 25 φ angles, supplemented by 3 ϕ and 15χ1 angles. The core of LDTI‐C is very well defined and consists of a short 310‐helix‐loop and a short two‐stranded antiparallel β‐sheet between residues 13–14 and 20–21. The N‐terminus is fixed to the core by two disulfide bridges, while the C‐terminus is connected to the β‐sheet via the third disulfide bridge. The binding loop in LDTI exhibits lowest energy conformations belonging to the canonical conformation of serine proteinase inhibitors.
ω‐agatoxin IVA blocks nicotinic receptor channels in bovine chromaffin cells
Authors: Granja Ricardo , Fernández-Fernández JoséM , Izaguirre Victor , González-García Carmen , Ceña Valentin
Published: July 2002

We have studied the contribution of P‐type voltage‐dependent Ca2+ channels to both catacholamine (CA) and ATP secretion from bovine chromaffin cells induced by high K+ or nicotine using ω‐agatoxin IVA, a selective blocker of P‐type voltage‐dependent Ca2+ channels. We found that high K+ (75 mM) induced the release of about 13% of norepinephrine, 5% epinephrine and 11% ATP, and that ω‐agatoxin (100 nM) did not affect this secretion. However, both nicotine‐induced CA and ATP secretion were significantly blocked (about 50%) by ω‐agatoxin IVA (100 nM). In addition, this toxin also reversibly blocked (about 70%) the inward current induced by nicotine in bovine chromaffin cells. The results suggest that, besides its known action of blocking P‐type voltage‐dependent channels, ω‐agatoxin is a potent and reversible blocker of the nicotinic receptor channel in chromaffin cells, and that this action would explain the blockade of nicotine‐induced secretion.
Lutein associated with a transthyretin indicates carotenoid derivation and novel multiplicity of transthyretin ligands
Authors: Pettersson Tom , Ernström Ulf , Griffiths William , Sjövall Jan , Bergman Tomas , Jörnval Hans
Published: July 2002

Transthyretins isolated from different species bind hydrophobic compounds and are often obtained in a yellow form. Such a transthyretin from chicken serum was purified by chromatography using Sepharose‐coupled human retinol‐binding protein. The yellow chromophore was extracted with methanol and purified by reverse phase HPLC followed by normal‐phase chromatography on a nitrile column. Ultraviolet‐visible absorbance and mass spectrometry identified the yellow compound as lutein, i.e. xanthophyll, (all‐trans)‐β,ϵ‐carotene‐3,3′‐diol, estimated to constitute 10–30% of associated colourless compounds. These components are different from the yellow component isolated from human transthyretin and establish that carotenoid‐derived pigments can be associated with transthyretins.
Enhancement of aromatic amino acid‐nucleic acid base stacking interaction by metal coordination to base: fluorescence study on a tryptophan‐Pt(II)‐guanine ternary complex
Authors: Hisahiro Kawai  , Mariko Tarui  , Mitsunobo Doi  , Toshimasa Ishida
Published: July 2002

In order to investigate the effect of the Pt(II) ion on the stacking interaction between tryptophan and a guanine base, the quenching of Trp fluorescence was monitored for some systems in the absence and presence of the metal ion, and the association constants were obtained by the analysis of Eadie‐Hofstee plots. All spectral data suggested that the stacking interaction is enhanced by the Pt(II) coordination to the guanine N7 atom. The result indicates the importance of the metal ion as a bookmark in the specific recognition of a nucleic acid base by an aromatic amino acid residue.
Abnormal lateralization in schizophrenia: empirical evidence for an integrated model
Authors: Karny N , Nachson I
Published: July 2002

Cerebral deficits in schizophrenia have been associated either with left hemisphere dysfunction, or with impairment in interhemispheric transfer. To test the relative efficacy of the two hypotheses, 63 right-handed subjects (24 paranoid schizophrenics, 21 nonparanoid schizophrenics, and 18 normal controls) were given two auditory lateral tasks: identification of dichotically delivered tonal sequences and digit sets. As the data analyses showed, more correct responses were given by the normal controls than by the patients, and by males than by females. Generally, report (especially from the ear reported second) was better from the right than from the left ear. This right ear advantage (which was more consistent in males than in females) was abnormally large for the paranoid schizophrenics who showed on both tests, relative to normal subjects, a slight decrement in right ear report and a significant decrement in left ear report. The data were interpreted as indicating left hemisphere dysfunction and structural callosal damage in paranoid schizophrenics.
SCN5A mutation (T1620M) causing Brugada syndrome exhibits different phenotypes when expressed in Xenopus oocytes and mammalian cells
Authors: Baroudi Ghayath , Carbonneau Eric , Pouliot Valérie , Chahine Mohamed
Published: July 2002

Brugada syndrome is a hereditary cardiac disease causing abnormal ST segment elevation in the ECG, right bundle branch block, ventricular fibrillation and sudden death. In this study we characterized a new mutation in the SCN5A gene (T1620M), causing the Brugada syndrome. The mutated channels were expressed in both Xenopus leavis oocytes and in mammalian tsA201 cells with and without the β‐subunit and studied using the patch clamp technique. Opposite phenotypes were observed depending on the expression system. T1620M mutation led to a faster recovery from inactivation and a shift of steady‐state inactivation to more positive voltages when expressed in Xenopus oocytes. However, using the mammalian expression system no effect on steady‐state inactivation was observed, but this mutation led to a slower recovery from inactivation. Our finding supports the idea that the slower recovery from inactivation of the cardiac sodium channels seen in our mammalian expression system could decrease the density of sodium channels during the cardiac cycle explaining the in vivo arrhythmogenesis in patients with Brugada syndrome.
C3A binds to the seven transmembrane anaphylatoxin receptor expressed by epithelial cells and triggers the production of IL‐8
Authors: Monsinjon Tiphaine , Gasque Philippe , Ischenko Alexander , Fontaine Marc
Published: July 2002

The complement (C) plays an important role in many acute inflammatory processes. C3a is an inflammatory polypeptide named anaphylatoxin, generated during C activation and which acts through a specific receptor C3aR. In this study, we demonstrated that the epithelial cell line ECV 304 constitutively expressed C3aR (by flow cytometry and immunofluorescence) and that binding of purified C3a to epithelial cells resulted in a time‐ and dose‐dependent upregulation of interleukin‐8 (IL‐8). Pre‐treatment of ECV 304 with pertussis toxin inhibited IL‐8 response induced by C3a, indicating that the action of C3a was mediated by a G protein coupled pathway.
ADP receptor antagonists inhibit platelet aggregation induced by the chemokines SDF‐1, MDC and TARC
Authors: Suttitanamongkol S , Gear A.R.L
Published: July 2002

The ability of the chemokines SDF‐1, MDC and TARC to induce platelet aggregation depends strongly on low levels of ADP. The ADP receptors involved have now been characterized using the P2Y1 and P2TAC receptor antagonists, A2P5P and AR‐C69931MX. Stimulation of aggregation by the chemokines at 10 s was not blocked by AR‐C69931MX, but was strongly inhibited by A2P5P. Pertussis toxin abolished the chemokine‐stimulated aggregation. We conclude that the P2Y1 ADP receptor plays a critical role in the initial phases of SDF‐1‐, MDC‐ and TARC‐induced platelet aggregation, which involve a pertussis toxin‐sensitive G protein.
Aspartic protease in leaves of common bean (Phaseolus vulgaris L.) and cowpea (Vigna unguiculata L. Walp): enzymatic activity, gene expression and relation to drought susceptibility
Authors: Cruz de Carvalho Maria H. , d'Arcy-Lameta Agnès , Roy-Macauley Harold , Gareil Monique , El Maarouf Hayat , Pham-Thi Anh-Thu , Zuily-Fodil Yasmine
Published: July 2002

Four cultivars of related species, common bean and cowpea, which exhibit different degrees of drought resistance, were submitted to water stress by withholding irrigation. Drought induced an increase in endoproteolytic activity, being higher in susceptible cultivars (bean) than in tolerant ones (cowpea). An aspartic protease activity was found to be strongly induced especially in bean. From a cowpea leaf cDNA library, a full length aspartic protease precursor cDNA was obtained. Transcript accumulation in response to water stress indicated that the expression of the gene was constitutive in cowpea and transcriptionally up‐regulated in bean. The results showed that drought‐tolerant and drought‐susceptible bean plants differ regarding aspartic protease precursor gene expression.
Characterization of a novel human putative mitochondrial transporter homologous to the yeast mitochondrial RNA splicing proteins 3 and 4
Authors: Li Fang-Yuan , Nikali Kaisu , Gregan Juraj , Leibiger Ingo , Leibiger Barbara , Schweyen Rudolf , Larsson Catharina , Suomalainen Anu
Published: July 2002

We report here a novel human gene, hMRS3/4, encoding a putative mitochondrial transporter structurally and functionally homologous to the yeast mitochondrial RNA splicing proteins 3 and 4. These proteins belong to the family of mitochondrial carrier proteins (MCF) and are likely to function as solute carriers. hMRS3/4 spans ∼10 kb of genomic DNA on chromosome 10q24 and consists of four exons that encode a 364‐aa protein with six transmembrane domains. A putative splice variant, encoding a 177‐aa protein with three transmembrane domains, was also identified. hMRS3/4 has a well‐conserved signature sequence of MCF and is targeted into the mitochondria. When expressed in yeast, hMRS3/4 efficiently restores the mitochondrial functions in mrs3omrs4o
knock‐out mutants. Ubiquitous expression in human tissues and a well‐conserved structure and function suggest an important role for hMRS3/4 in human cells.
Insulin modulates leptin‐induced STAT3 activation in rat hypothalamus
Authors: Carvalheira José B.C. , Siloto Rodrigo M.P. , Ignacchitti Inara , Brenelli Sigisfredo L. , Carvalho Carla R.O. , Leite Adilson , Velloso Lı́cio A. , Gontijo José A.R. , Saad Mario J.A.
Published: July 2002

Insulin and leptin have overlapping effects in the control of energy homeostasis, but the molecular basis of this synergism is unknown. Insulin signals through a receptor tyrosine kinase that phosphorylates and activates the docking proteins IRSs (insulin receptor substrates), whereas the leptin receptor and its associated protein tyrosine kinase JAK2 (Janus kinase 2) mediate phosphorylation and activation of the transcription factor STAT3 (signal transducer and activator of transcription). Here, we present evidence for the integration of leptin and insulin signals in the hypothalamus. Insulin induced JAK2 tyrosine phosphorylation, leptin receptor phosphorylation which, in the presence of leptin, augmented the interaction between STAT3 and this receptor. Insulin also increased the leptin‐induced phosphorylation of STAT3 and its activation. These results indicate that insulin modulates the leptin signal transduction pathway, and may provide a molecular basis for the coordinated effects of insulin and leptin in feeding behavior and weight control.
Chondroitin 4‐sulphate exhibits inhibitory effect during Cu2+‐mediated LDL oxidation
Authors: Albertini Riccardo , Ramos Pilar , Giessauf Andreas , Passi Alberto , De Luca Giancarlo , Esterbauer Hermann
Published: July 2002

© 1997 Federation of European Biochemical Societies.
pH‐induced transition and Zn2+‐binding properties of bovine prolactin1
Authors: Permyakov Eugene A. , Veprintsev Dmitry B. , Deikus Gintaras Y. , Permyakov Serge E. , Kalinichenko Lina P. , Grishchenko Valery M. , Brooks Charles L.
Published: July 2002

A pH‐induced conformational transition was found in bovine prolactin within the physiologically significant pH region from 6.5 to 8.5. The thermal stability of prolactin at pH 6.5 is essentially higher than at pH 8.5. Bovine prolactin binds zinc ions with an apparent association constant of 2×105 M−1 at pH 6.5 and 1×104 M−1 at pH 8.5. The pH dependence of both thermal stability and zinc binding surrounding the pK
a of histidine suggests that these residues plays a key role in the structural integrity of bovine prolactin.
The endogenous cardiac sarcoplasmic reticulum Ca2+/calmodulin‐dependent kinase is activated in response to β‐adrenergic stimulation and becomes Ca2+‐independent in intact beating hearts
Authors: Baltas Leonidas G , Karczewski Peter , Bartel Sabine , Krause Ernst-Georg
Published: July 2002

We investigated the effects of β‐adrenergic stimulation on the activity of the endogenous cardiac sarcoplasmic reticulum Ca2+/calmodulin‐dependent protein kinase (SRCaM kinase) in Langendorff‐perfused rat hearts. We found that isoproterenol induced generation of autonomous (Ca2+‐independent) SRCaM kinase activity to 28±4.4% of the total activity. Moreover, dephosphorylation of the autonomous SRCaM kinase with protein phosphatase 2A resulted in an enzyme that was again dependent on Ca2+ and calmodulin for its activity. Activation of SRCaM kinase was coupled to phospholamban phosphorylation and activation of the cAMP‐signaling system. Our results suggest that the cardiac SRCaM kinase is activated in response to β‐adrenoceptor stimulation. This activation stimulates autophosphorylation at its regulatory domain and converts it to an active Ca2+‐independent species that may be the basis for potentiation of Ca2+ transients in the heart.
Free luciferase may acquire a more favorable conformation than ribosome‐associated luciferase for its activity expression
Authors: Yang Feng , Jing Guo-Zhong , Zhou Jun-Mei , Zheng Yan-Zhen
Published: July 2002

A variant of firefly luciferase in which the C‐terminal end was extended with 44 amino acid residues served as a model protein in this study. After transcription and translation in vitro, the enzyme activity was measured when still attached to the ribosome and when released from the ribosome by incubation with RNase A or puromycin. It was found that the C‐terminally extended luciferase already had activity when linked to the ribosome, but its activity was greatly increased when released from the ribosome. These results indicate that the luciferase is folded during synthesis on the ribosome; however, some conformational adjustments occur after its release from the ribosome which are required for the full expression of its enzymatic activity.
The intact urokinase receptor is required for efficient vitronectin binding: receptor cleavage prevents ligand interaction
Authors: Høyer-Hansen Gunilla , Behrendt Niels , Ploug Michael , Danø Keld , Preissner Klaus T
Published: July 2002

The urokinase receptor (uPAR) is a receptor for both urokinase plasminogen activator (uPA) and the adhesion protein vitronectin. There are two forms of cell surface‐bound uPAR; intact uPAR and a cleaved form, uPAR(2+3), which is formed by uPA‐catalyzed cleavage of uPAR. In ligand‐blotting experiments we found that vitronectin binds uPAR but not uPAR(2+3). In real‐time biomolecular interaction analysis using recombinant, soluble uPAR (suPAR) both plasma and multimeric forms of vitronectin bound to intact, antibody‐immobilized suPAR. Monoclonal antibodies against domain 1 of uPAR blocked suPAR binding to vitronectin and vitronectin did not interact with suPAR(2+3). Both suPAR(2+3) and the isolated domain 1 failed to compete with the intact suPAR in binding to vitronectin. We therefore conclude that the intact receptor is required for efficient vitronectin binding.
High concentration of glucose causes impairment of the function of the glutathione redox cycle in human vascular smooth muscle cells
Authors: Tachi Yoichi , Okuda Yukichi , Bannai Chieko , Okamura Naomichi , Bannai Shiro , Yamashita Kamejiro
Published: July 2002

We demonstrated that high glucose reduced H2O2 scavenge activity in human vascular smooth muscle cells. In the cells exposed to high glucose, the intracellular glutathione content decreased, although the NADPH content was unchanged. The rate of uptake of cystine, which is a rate‐limiting precursor of the glutathione synthesis, decreased in the high glucose group compared with the control group. These decreases were shown to be dependent on glucose concentration. It was suggested that high glucose causes impairment of the function of the glutathione redox cycle in human vascular smooth muscle cells, resulting in reduced H2O2 scavenge activity.
A peptide derived from the N‐terminal region of HIV‐1 Vpr promotes nuclear import in permeabilized cells: elucidation of the NLS region of the Vpr
Authors: Karni Orit , Friedler Assaf , Zakai Nehama , Gilon Chaim , Loyter Abraham
Published: July 2002

Viral protein r (Vpr), a HIV‐1 auxiliary protein which mediates nuclear import of the viral preintegration complex (PIC), contains two regions, N‐ and C‐terminal, which have been proposed to function as a nuclear localization signal (NLS). We have synthesized peptides corresponding to both regions (designated as VprN and VprC), conjugated them to bovine serum albumin (BSA), and tested their ability to mediate nuclear import in permeabilized cells. Only VprN, and not VprC, functioned as an active NLS and promoted translocation of the conjugate into nuclei. Nuclear import of the conjugate was found to be energy and temperature dependent and was inhibited by wheat germ agglutinin (WGA). However, it did not require the addition of cytosolic factors and was not inhibited by the prototypic SV40 large T‐antigen NLS peptide. Our results show that Vpr harbours a non‐conventional negatively charged NLS and therefore suggest that Vpr may use a distinct nuclear import pathway.
Lysophosphatidylcholine upregulates CD40 ligand expression in newly activated human CD4+ T cells
Authors: Sakata-Kaneko Shizuka , Wakatsuki Yoshio , Usui Takashi , Matsunaga Yoichi , Itoh Toshiyuki , Nishi Eiichiro , Kume Noriaki , Kita Toru
Published: July 2002

Lysophosphatidylcholine (lyso‐PC) accumulates in tissues undergoing inflammation and atherosclerosis, where an infiltration of T cells is also seen. We found that lyso‐PC increased IFN‐γ production and CD40L expression in CD4+ T cells stimulated with anti‐CD3 Ab and recombinant CD80 molecules, whereas lyso‐PC did not affect IL‐2 and IL‐4 production. These results suggest that lyso‐PC, in combination with other stimuli, may regulate CD4+ T cell functions to propagate local inflammatory reactions and also imply a novel role played by a modified lipid in the selection of Th1/Th2 immune response as well as in the T cell mediated pathogenesis in atherosclerosis.
Retracing the evolution of amino acid specificity in glutaminyl‐tRNA synthetase
Authors: Hong Kwang-Won , Ibba Michael , Söll Dieter
Published: July 2002

Molecular phylogenetic studies of glutaminyl‐tRNA synthetase suggest that it has relatively recently evolved from the closely related enzyme glutamyl‐tRNA synthetase. We have now attempted to retrace one of the key steps in this process by selecting glutaminyl‐tRNA synthetase mutants displaying enhanced glutamic acid recognition. Mutagenesis of two residues proximal to the active site, Phe‐90 and Tyr‐240, was found to improve glutamic acid recognition 3–5‐fold in vitro and resulted in the misacylation of tRNAGlnwith glutamic acid. In vivo expression of the genes encoding these misacylating variants of glutaminyl‐tRNA synthetase reduced cellular growth rates by 40%, probably as a result of an increase in translational error rates. These results provide the first biochemical evidence that glutaminyl‐tRNA synthetase originated through duplication and consequent diversification of an ancestral glutamyl‐tRNA synthetase‐encoding gene.
cDNA cloning of an adult male putative lipocalin specific to tergal gland aphrodisiac secretion in an insect (Leucophaea maderae)
Authors: Korchi Ahmed , Brossut Rémy , Bouhin Hervé , Delachambre Jean
Published: July 2002

Lma‐P22 is a cuticular surface protein specific to the tergal gland secretion of Leucophaea maderae adult males which is ingested by females just before copulation. The complete Lma‐P22 cDNA sequence was determined by RT‐PCR using primers based on Edman degradation fragments. The recombinant protein expressed in Escherichia coli was recognized by an anti‐Lma‐P22 antibody. Northern blot analysis indicates that the corresponding mRNA is transcribed only in the epidermis of male tergites. Sequence analysis indicated that Lma‐P22 deduced protein belongs to the lipocalin family. Lipocalins are extracellular proteins which carry hydrophobic compounds and some of them can bind sexual pheromone in vertebrates. Lma‐P22 is the first example of a lipocalin‐like protein involved in insect sexual behavior.
Localization and age‐dependent expression of the inward rectifier K+ channel subunit Kir 5.1 in a mammalian reproductive system
Authors: Salvatore Lorena , D'Adamo Maria Cristina , Polishchuk Roman , Salmona Mario , Pessia Mauro
Published: July 2002

Kir 5.1 is a member of the inward rectifier potassium channel superfamily which does not form functional channels when expressed by itself in Xenopus laevis oocytes. rt‐PCR reveals high levels of Kir 5.1 mRNA expression in testis but the function of this channel remains unknown. To determine the cell‐specific expression of this channel in the testis we raised a polyclonal antibody against an external epitope of Kir 5.1 and tested its specificity in Xenopus oocytes expressing several cloned Kir subunits. Strong immunoreactivity for Kir 5.1 was found in seminiferous tubules of rat testis and, particularly, in spermatogonia, primary and secondary spermatocytes, spermatids and in the head and body of spermatozoa. The intensity of Kir 5.1 immunofluorescence, quantified using laser scanning microscopy, increased with age at every stage in the development of sperm from spermatogonia and reached a peak in 60‐day‐old rats. In contrast, the immunofluorescence decreased in 90‐day‐old animals and was detected mostly in spermatozoa. The results demonstrate that Kir 5.1 expression in the testis is localised to cells involved in spermatogenesis, showing a temporal pattern of expression during sexual maturity.
Kinetics of CheY phosphorylation by small molecule phosphodonors
Authors: Da Re Sandra S. , Deville-Bonne Dominique , Tolstykh Tatiana , Véron Michel , Stock Jeffry B.
Published: July 2002

The chemotaxis response regulator CheY can acquire phosphoryl groups either from its associated autophosphorylating protein kinase, CheA, or from small phosphodonor molecules such as acetyl phosphate. We report a stopped‐flow kinetic analysis of CheY phosphorylation by acetyl phosphate. The results show that CheY has a very low affinity for this phosphodonor (K
s≫0.1 M), consistent with the conclusion that, whereas CheY provides catalytic functions for the phosphotransfer reaction, the CheA kinase may act simply to increase the effective phosphodonor concentration at the CheY active site.
The proteasome inhibitor PI31 competes with PA28 for binding to 20S proteasomes
Authors: Zaiss Dietmar M.W. , Standera Sybille , Holzhütter Hergo , Kloetzel Peter-M. , Sijts Alice J.A.M.
Published: July 2002

PI31 is a previously described inhibitor of 20S proteasomes. Using recombinant PI31 we have analyzed its effect on proteasomal hydrolyzing activity of short fluorogenic substrates and of a synthetic 40‐mer polypeptide. In addition, we investigated its influence on the activation of 20S proteasome by the proteasome activator PA28. PI31 inhibits polypeptide degradation already at concentrations which only partially inhibit fluorogenic substrate turnover and immunosubunits do not influence the PI31 binding affinity. Furthermore our data demonstrate that PI31 is a potent competitor of PA28‐mediated activation.
A novel downstream positive regulatory element mediating transcription of the human high mobility group (HMG) I‐C gene
Authors: Chau Kai-Yin , Arlotta Paola , Patel Umesh A. , Crane-Robinson Colyn , Manfioletti Guidalberto , Ono Santa Jeremy
Published: July 2002

The high mobility group (HMG) I proteins are small, non‐histone chromosomal proteins that promote gene activation during development and within rapidly dividing cells. They do so by facilitating enhanceosome formation on inducible genes, via both protein/DNA and protein/protein interactions. The HMG I‐C gene is tightly regulated, normally being expressed exclusively during embryonic development. However, HMG I‐C expression is also observed frequently in a number of tumor types, and this expression has been shown to contribute to the malignant transformation process. With the aim of dissecting pathways that lead to aberrant expression of HMG I‐C in tumor cells, we have analyzed HMG I‐C gene regulation in the human hepatoma cell line PLC/PRF/5. One of the two HMG I‐C transcripts detected in this cell line originates from a novel downstream initiation site at nucleotide −161 relative to the first methionine. Transcription from the downstream initiation site is mediated by a PRE located between nt −222 and −217. We show here that the Sp1 and Sp3 transcription factors interact with the PRE and transactivate the HMG I‐C promoter in a cooperative fashion. This study provides the first characterization of this downstream HMG I‐C promoter.
Activation of interstitial collagenase, MMP‐1, by Staphylococcus aureus cells having surface‐bound plasmin: a novel role of plasminogen receptors of bacteria
Authors: Santala A. , Saarinen J. , Kovanen P. , Kuusela P.
Published: July 2002

Plasmin, the enzymatically active form of plasminogen, can activate several matrix metalloproteinases (MMPs). In this study, we investigated the activation of MMP‐1, one of the major interstitial collagenases, by plasmin which was generated on the surface of Staphylococcus aureus cells. Plasmin bound to plasminogen receptors on S. aureus degraded the major 125I‐labeled 55‐kDa proMMP‐1 into the 42‐kDa form corresponding to the size of active MMP‐1. MMP‐1 formed by S. aureus‐bound plasmin was also enzymatically active as judged by digestion of the synthetic collagenase substrate, DNP‐Pro‐Leu‐Gly‐Leu‐Trp‐Ala‐D‐Arg‐NH2. The finding that, in MMP‐1 molecules generated either by soluble plasmin or by S. aureus‐bound plasmin, the amino‐terminal amino acid sequences were identical indicated that the activation mechanisms of the two plasmin forms do not differ from each other. The present observations emphasise and broaden the physiological importance of bacterial plasminogen receptors. In addition to direct proteolytic effects on components of the extracellular matrix, receptor‐bound plasmin is also capable of initiating an MMP‐1‐dependent matrix‐degrading enzymatic cascade.
Operations safety: an assessment of a commercial aviation safety program
Authors: McFadden Kathleen L. , Hosmane Balakrishna S.
Published: July 2002

Operations safety is an important issue in operations management. While prior studies have focused on the operational performance of various airlines and airports, few have assessed the efficacy of government airline safety programs. This empirical study evaluates a commercial aviation safety program that sanctions pilots with alcohol‐related motor vehicle convictions. We compare a 5‐year period prior to the implementation of the program against a 5‐year period after implementation using data on over 160,000 commercial pilots. We conclude that the FAA’s handling of pilots with motor vehicle convictions has had a negligible effect on airline safety. These results have operational as well as public policy implications.
Excitotoxicity in neurological disorders — the glutamate paradox
Authors: Obrenovitch T.P. , Urenjak J. , Zilkha E. , Jay T.M.
Published: July 2002

Beneficial effects of glutamate‐receptor antagonists in models of neurological disorders are often used to support the notion that endogenous excitotoxicity (i.e. resulting from extracellular accumulation of endogenous glutamate) is a major contributor to neuronal death associated with these conditions. However, this interpretation conflicts with a number of robust and important experimental evidence. Here, emphasis is placed on two key elements: (i) very high extracellular levels of glutamate must be reached to initiate neuronal death, far above those measured in models of neurological disorders; and (ii) changes in extracellular glutamate as measured by microdialysis are not related to changes in the synaptic cleft, i.e. the compartment where neurotransmitter glutamate interacts with its receptors.

It has become clear that the diversity and complexity of glutamate‐mediated processes allow for a wide range of potential abnormalities (e.g. loss of selectivity of glutamate‐operated ion channels, abnormal modulation of glutamate receptors). In addition, as neuronal death subsequent to ischemia and other insults is likely to result from multifactorial processes that may be inter‐related, inhibition of glutamate‐mediated synaptic transmission may be neuroprotective by increasing the resistance of neurons to other deleterious mechanisms (e.g. inadequate energy supply) that are not directly related to glutamatergic transmission.
“Old”, “New” and “Post” Liberal Attitudes Toward the West: From Love to Hate
Authors: Shlapentokh Vladimir
Published: July 2002

In the last few years, significant changes in the attitudes toward the West have occurred in Russia. While “old” Russian liberals, like Egor Gaidar, treated the West as a Russian ally, the “new” liberals, such as Boris Nemtsov, perceived the West as a rival approaching, in this respect, Russian communists and nationalists who see in the West an eternal enemy. The author describes this change using various information from the Russian media and surveys.
Community–Continuum in Biogeography
Authors: Hakkenberg Christopher R. , Tarasi Dennis D. , Cushman Samuel , Peet Robert K.
Published: March 2021

The community–continuum concept subsumes two contrasting yet complementary approaches to characterizing ecological communities (i.e., species assemblages) that simultaneously embrace communities as distinct and repeatable units while recognizing the continuous nature of their compositional variation. While both terms reference physical entities populating landscapes as well as compositional categories comprising ecological classification systems, the distinction between them emphasizes two important dichotomies: discrete versus continuous composition, and predictability versus stochasticity in community fidelity to environmental conditions. While most ecological analyses adopt the continuum model for its realistic characterization of compositional variation, the classification of communities into discrete types is expedient and effective, particularly for management applications, provided the sometimes‐arbitrary nature of these entities is recognized. A flexible ecological classification typology recognizes that species associations are empirically observable and that broadly defined community types exist in replicate, even if their composition reflects idiosyncrasy and dynamism along a continuum of variation.
Participatory Mapping
Authors: Ollivierre Alison DeGraff , Burnett Charla M. , Hetoevėhotohke'e Lucchesi Annita
Published: March 2021

Participatory mapping is a human practice that spans thousands of years. From oral storytelling to the first hand‐drawn maps, participatory processes and methods have always been used in cartography and planning and yet the term “participatory mapping” did not become popular until the 1990s. For many practitioners, participatory mapping can be used to broaden access to spatial data and technology for socially and economically marginalized groups to facilitate decision‐making. Activists use participatory mapping to protect indigenous and experiential knowledge and advocate for local knowledge to reshape policy and foster normative behavioral change around land‐use concepts. From conservation and natural resource management, to rural or urban planning, to social and environmental activism and advocacy, participatory mapping is an important tool to understand the production of spatial knowledge.
Ice Caves
Authors: Lipar Matej , Zorn Matija , Perko Drago
Published: March 2021

Ice caves are caves in rock with perennial ice accumulation. They differ from glacier caves, which are caves formed in ice. They can occur at higher elevations and higher latitudes, where the mean annual surface air temperature is below freezing, but the majority are found in regions with a mean annual surface air temperature above freezing, owing their existence merely to a particular cave microclimate. Such microclimates are responsible for zones of negative temperature anomalies where ice accumulation takes place. The ice mostly accumulates as frozen water, but deposition of snow through vertical cave entrances can also result in ice diagenesis. Historical reports of ice caves can be traced back to as early as the twelfth century. Their recognition has grown greatly in recent years because cave ice and the cryogenic cave minerals therein offer numerous proxies for paleoclimatological and paleoenvironmental studies.
Paraglaciation
Authors: Ballantyne Colin K.
Published: March 2021

Paraglaciation describes the ways in which glaciated landscapes adapt to glacier‐free conditions during and after deglaciation. Glacially weakened rock slopes respond through catastrophic failure, rock‐slope deformation, or episodic rockfall; sediment‐mantled slopes become gullied; glacier forelands are subject to mass movement, deflation, and fluvial erosion; alluvial fans and floodplains aggrade, then are incised by their parent streams; and barrier coasts undergo progradation or retrogradation, depending on sediment supply and sea level rise or fall. The paraglacial system can be represented by an interrupted sediment cascade whereby nonrenewable (glacigenic) sediment sources are reworked by a range of surface processes into sediment stores (talus, debris cones, alluvial fans, floodplains) and ultimately to sediment sinks (valley fills, lakes, offshore). Rates of sediment reworking by nonglacial processes are initially rapid but decline as sediment supply becomes depleted. “Glacial” landscapes reflect not only the long‐term operation of glacial processes, but also multiple intervening episodes of paraglacial modification.
Integrated Assessment Models
Authors: Thomson Marcus J.
Published: March 2021

Integrated assessment models (IAMs) are analytical frameworks that combine computer models of physical and socioeconomic phenomena to provide insights on their interactions. There are two major classes of IAMs, CB‐IAMs and DP‐IAMs. CB‐IAMs are highly reduced representations of socioeconomic and climate sectors used for cost–benefit analyses of economic growth balanced against future economic damage due to climate change. DP‐IAMs are higher‐complexity models used to determine pathways to future greenhouse gas mitigation targets, or analyze the impacts of environmental change on the sectors they represent. IAMs play a central role in the economic, social, and political science of climate change research and policymaking. Ensuring geographical variation and connectivity is properly incorporated into IAMs is an important challenge.
Post‐Military Geographies
Authors: Yarwood Richard
Published: March 2021

Post‐military geographies are concerned with transitions from military to civilian space. Geographers have examined the impact and legacy of changing military activities on places, particularly where there is a reduction or cessation of military activities, largely in urban centers of the West. Recognizing that transition is a process rather than an event, geographers have examined how post‐military space has been restructured, imagined, and performed. Work in this area also fits into a broader cannon of critical military geography, which is in itself attempting to draw away from militaristic studies that have often characterized geographical endeavor to date.
Praxis
Authors: McClelland Andrew G.
Published: March 2021

Praxis concerns the ability of subaltern groups facing oppression to positively transform their world through social action. In essence, it entails a conscious collaborative struggle through action and reflection to overcome oppressive power relations. Praxis is philosophically rooted in the writings of Aristotle and Marx, with other influential proponents including Antonio Gramsci and Paulo Freire. Within geography, it is commonly associated with theoretical positions actively engaged with emancipatory agendas. Feminist geographies, in particular from the 1970s, provided inspiration for the praxis of other subaltern groups. Today, praxis is characterized by a constellation of forms and techniques within and beyond the academy, ranging from teaching and writing to engaging in policy processes, involvement with grassroots community groups, campaigns, and civil disobedience. While academic praxis is challenged by significant structural factors, many scholars seek to effect progressive change on social, economic, and environmental issues in mutual solidarity with others.
Cell‐Based Delivery Systems: Emerging Carriers for Immunotherapy
Authors: Li Zhaoting , Wang Yixin , Ding Yingyue , Repp Lauren , Kwon Glen S. , Hu Quanyin
Published: March 2021

Immunotherapy is leading a paradigm shift in the treatment of various diseases, including tumors, auto‐immune diseases, and infectious diseases. However, the limited response rate and systemic side effects significantly impede the clinical applications of immunotherapy. As natural carriers for proteins and molecules, cells with low immunogenicity and toxicity have attracted considerable attention for biomedical applications and have achieved encouraging progress especially in immunotherapy. The convergence of multiple disciplines has equipped cell‐based delivery systems with control over their spatiotemporal distribution to enhance treatment efficacy and reduce side effects. Here, an overview of the fundamentals and design principles of cell‐based delivery systems followed by a perspective that includes the most recent advances of various cells as delivery carriers, with a special focus on the implications of cell‐based delivery systems for immunotherapy is offered.
Biomimetic Nanoparticles as a Theranostic Tool for Traumatic Brain Injury
Authors: Zinger Assaf , Soriano Sirena , Baudo Gherardo , De Rosa Enrica , Taraballi Francesca , Villapol Sonia
Published: March 2021

Traumatic brain injury (TBI) triggers both central and peripheral inflammatory responses. Existing pharmacological drugs are unable to effectively and quickly target the brain inflamed regions, setting up a major roadblock towards effective brain trauma treatments. Nanoparticles (NPs) have been used in multiple diseases as drug delivery tools with remarkable success due to their rapid diffusion and specificity in the target organ. Here, leukocyte‐based biomimetic NPs are fabricated as a theranostic tool to directly access inflamed regions in a TBI mouse model. This NP systemic delivery is visualized using advanced in vivo imaging techniques, including intravital microscopy and in vivo imaging system. The results demonstrate selective targeting of NPs to the injured brain and increased NPs accumulation among the peripheral organs 24 h after TBI. Interestingly, increased microglial proliferation, decreased macrophage infiltration, and reduced brain lesion following the NPs treatments compared to sham vehicle‐treated mice are also found. In summary, the results suggest that NPs represent a promising future theranostic tool for TBI treatment.
Light‐Controlled Nanosystem with Size‐Flexibility Improves Targeted Retention for Tumor Suppression
Authors: Luo Huanhuan , Kong Li , Zhang Feng , Huang Chenglong , Chen Jiayi , Zhang Hongbo , Yu Han , Zheng Song , Xu Hongwei , Zhang Yiran , Deng Lianfu , Chen Gang , Santos Hélder A. , Cui Wenguo
Published: March 2021

Although great promise has been achieved with nanomedicines in cancer therapy, limitations are still encountered, such as short retention time in the tumor. Herein, a nanosystem that can modulate the particle size in situ by near‐infrared (NIR) light is self‐assembled by cross‐linking the surface‐modified poly(lactic‐co‐glycolic acid) from the up‐conversion nanoparticle with indocyanine green and doxorubicin–nitrobenezene–polyethylene glycol (DOX–NB–PEG). The nanosystem with its small size (≈100 nm) achieves better tumor targeting, while the PEG on the surface of the nanosystem can effectively shield the adsorption of proteins during blood circulation, maintaining a stable nanostructure and achieving good tumor targeting. Moreover, the nanosystem at the tumor realizes the rapid shedding of PEG on its surface by NIR irradiation, and the enhanced cellular uptake. At the same time, aggregation occurs inside the nanosystem to form bigger particles (≈600 nm) in situ, prolonging the retention time at the tumor and producing enhanced targeted therapeutic effects. In vitro data show higher cellular uptake and a higher rate of apoptosis after irradiation, and the in vivo data prove that the nanosystem have a longer residence time at the tumor site after NIR irradiation. This nanosystem demonstrates an effective therapeutic strategy in targeted synergistic tumors.