bluuebunny/crossref_metadata_2025 huggingface dataset:
Mode of disulfide bond formation of a heat‐stable enterotoxin (STh) produced by a human strain of enterotoxigenic Escherichia coli
Authors: Shimonishi Yasutsugu , Hidaka Yuji , Koizumi Michiyuki , Hane Motomu , Aimoto Saburo , Takeda Tae , Miwatani Toshio , Takeda Yoshifumi
Published: July 2002

To determine the modes of three disulfide linkages in the heat‐stable enterotoxin (STh) produced by a human strain of enterotoxigenic Escherichia coli, we synthesized STh(6–18), which consists of 13 amino acid residues and has the same intramolecular disulfide linkages as native STh [(1985) FEBS Lett. 181, 138–142], by stepwise and selective formation of disulfide bonds using different types of removable protecting groups for the Cys residues. Synthesis of the peptide with different modes of disulfide bond formation provided three peptides consistent with standard STh(6–18) in their physicochemical and biological properties, thereby indicating that the disulfide bonds in STh(6–18) are
E. coli F1 ‐ATPase: Site‐directed mutagenesis of the β‐subunit
Authors: Parsonage Derek , Wilke-Mounts Susan , Senior Alan E.
Published: July 2002

Residues βGlu‐181 and βGlu‐192 of E. coli F1‐ATPase (the DCCD‐reactive residues) were mutated to Gln. Purified βGln‐181 F1 showed 7‐fold impairment of ‘unisite’ Pi formation from ATP and a large decrease in affinity for ATP. Thus the β‐181 carboxyl group in normal F1 significantly contributes to catalytic site properties. Also, positive catalytic site cooperativity was attenuated from 5 × 104‐ to 548‐fold in βGln‐181 F1. In contrast, purified βGln‐192 F1 showed only 6‐fold reduction in ‘multisite’ ATPase activity. Residues βGly‐149 and βGly‐154 were mutated to Ile singly and in combination. These mutations, affecting residues which are strongly conserved in nucleotide‐binding proteins, were chosen to hinder conformational motion in a putative ‘flexible loop’ in β‐subunit. Impairment of purified F1‐ATPase ranged from 5 to 61%, with the double mutant F1 less impaired than either single mutant. F1 preparations containing βIle‐154 showed 2‐fold activation after release from membranes, suggesting association with F0 restrained turnover on F1 in these mutants.
Limited proteolysis of actin by a specific bacterial protease
Authors: Khaitlina S.Yu. , Smirnova T.D. , Usmanova A.M.
Published: July 2002

A 36 kDa fragment of rabbit skeletal muscle actin resistant to further proteolytic breakdown was obtained with a new bacterial protease. This fragment was the only cleavage product obtained from native actin whereas proteolysis of heat‐inactivated actin was unlimited. The 36 kDa fragment failed to polymerize and to inhibit DNase I activity. Binding to DNase I protects actin against proteolysis by protease. The results on actin proteolysis by different proteases are compared.
19F NMR detection of a fluorine‐labelled enzyme in vivo
Authors: Brindle Kevin , Williams Simon-Peter , Boulton Mark
Published: July 2002

Phosphoglycerate kinase was fluorine‐labelled in the yeast Saccharomyces cerevisiae by inducing enzyme synthesis in the presence of 5‐fluorotryptophan. 19F NMR measurements on the intact cells showed two resonances from the two tryptophan residues in the protein. The chemical shifts of these resonances were sensitive to the metabolic status of the cells.
Expression of insulin‐like growth factor‐IA and factor‐IB mRNA in human liver, hepatoma cells, macrophage‐like cells and fibroblast
Authors: Nagaoka Isao , Someya Akimasa , Iwabuchi Kazuhisa , Yamashita Tatsuhisa
Published: July 2002

The human insulin‐growth factor‐I (IGF‐1) gene codes for two transcripts, IGF‐IA and IGF‐IB mRNAs, formed by alternative splicing. In this study, the expression of these IGF‐I mRNA transcripts was examined using human liver, hepatoma cells, macrophage‐like cells and fibroblasts. The reverse transcription‐polymerase chain reaction revealed that these cells contained both IGF‐IA mRNA (representing exons I, II, III and V) and IGF‐IB mRNA (representing exons I, II, III and IV). Interestingly, an RNase protection assay using 32P‐labeled IGF‐IA and IGF‐IB exon‐specific cRNA probes demonstrated that IGF‐IA mRNA was 10‐fold more abundant than IGF‐IB mRNA in these cells. However, there was no difference in the stabilities of IGF‐IA and IGF‐IB mRNA. These observations indicate that IGF‐IA mRNA is more expressed than IGF‐IB mRNA in these cells independent of their stabilities.
Crystal structure of hevein at 2.8 Å resolution
Authors: Rodríguez-Romero A. , Ravichandran K.G. , Soriano-García M.
Published: July 2002

The three‐dimensional structure of hevein, a low molecular weight protein isolated from the latex of Hevea brasiliensis, has been determined by X.ray diffraction at 2.8 Å resolution, The protein crystallizes in space group P212121, with lattice constants a = 21.78, b = 31.86, c = 51.12 Å. The structure was solved by molecular replacement methods using the domain C of wheat germ agglutinin (WGA) as search model. The positions and individual isotropic temperature factors of the 324 atoms have been refined by the Hendrickson and Konnert restrained refinement procedure. While tight restraints have been maintained on the bonded distances and angles, the R‐factor has dropped to 24.1 % and an averaged B value of 9.5 Å1, using 78% (802) of the total possible number of reflections in the resolution range 5–2.8 Å. The tertiary structure is very similar to that of domain C of WGA from residues 3–31.
Ubiquinone biosynthesis Cloning of the genes coding for chorismate pyruvate‐lyase and 4‐hydroxybenzoate octaprenyl transferase from Escherichia coli
Authors: Siebert M. , Bechthold A. , Melzer M. , May U. , Berger U. , Schröder G. , Schröder J. , Severin K. , Heide L.
Published: July 2002

Chorismate pyruvate‐lyase activity was detected in extracts of Escherichia coli. 4‐Hydroxybenzoate was identified as the product of the enzymatic reaction by chemical derivatization and GC‐MS analysis. The ubiC gene, coding for the chorismate pyruvate‐lyase, was cloned and sequenced. The molecular weight of the gene product was calculated as 18.776 Da and confirmed by expression of the protein in E. coli minicells. The ubiA gene, coding for the 4‐hydroxybenzoate octaprenyl transferase, was identified by sequence homology and complementation of a ubiA
− strain. It is located directly downstream of ubiC in a typical operon structure.
The reaction of ascorbic acid with different heme iron redox states of myoglobin
Authors: Giulivi Cecilia , Cadenas Enrique
Published: July 2002

The interaction of ascorbate with different heme iron redox states of myoglobin (ferrylmyoglobin, FeIV=O; metmyoglobin, FeIII; and oxymyoglobin FeIIO2) was examined by e.s.r. and absorption spectroseopy. The reaction of ascorbate with ferryl‐ or met‐myoglobin resulted in ascorbyl radical production. The interaction of ascorbate with oxymyoglobin proceeded with formation of ascorbyl radical, hydrogen peroxide, and an overall oxidation of oxymyoglobin to metmyoglobin. The latter reaction proceeded via an oxoferryl complex intermediate ‐ corresponding to ferrylmyoglobin and identified by treatment of the reaction mixture with Na2S. These observations are consistent with a concerted electron transfer mechanism, whereby the two electrons required for the reduction of oxygen to hydrogen peroxide are donated by ascorbic acid and the heme iron. The antioxidant and prooxidant aspects of these redox transitions are discussed in terms of their kinetic properties.
Unusual DAhydrations in anaerobic bacteria: considering ketyls (radical anions) as reactive intermediates in enzymatic reactions
Authors: Buckel Wolfgang
Published: July 2002

DAhydratases have been DAtected in anaerobic bacteria which use 2‐, 4‐ or 5‐hydroxyacyl‐CoA as substrates and are involved in the removal of hydrogen atoms from the unactivated β‐ or γ‐positions. In addition there are bacterial DAhydratases acting on 1,2‐diols which are substrates lacking any activating group. These enzymes contain either FAD, or flavins + iron‐sulfur clusters or coenzyme B12. It has been proposed that the overall DAhydrations are actually reductions followed by oxidations or vice versa mediated by these prosthetic groups. Whereas the γ‐hydrogen of 5‐hydroxyvaleryl‐CoA is activated by a transient two‐electron α,β‐oxidation, the other substrates are proposed to require either a transient one‐electron reduction or an oxidation to a ketyl (radical anion).
Telomerase activity in plant cells
Authors: Fajkus Jiří , Kovařík Aleš , Královics Robert
Published: July 2002

Telomerase is a ribonucleoprotein enzyme which elongates the G‐rich strand of telomeric DNA to compensate for the progressive reduction in its length due to incomplete replication of chromosome ends, which in human somatic cells leads to cell cycle arrest upon shortening of telomeres to a critical length. To examine the possible involvement of telomerase in metabolism of plant genetic material, we used cells of Nicotiana tabacum strain TBY‐2, a stable long‐term culture which has kept a constant pattern of restriction fragments from chromosome termini during its 6 month period of cultivation in our laboratory. In a direct assay for telomerase, a 5′ end‐labeled plant telomeric oligonucleotide 5′(TTTAGGG)6
3′ was elongated in a TBY‐2 cell extract, showing a pausing pattern which is a characteristic feature of telomerases from other organisms. The elongation was inhibited by RNase A pretreatment of the extract. We conclude that plant cells possess telomerase which is used for maintenance of their telomeres.
The hematopoietic cytokine, colony‐stimulating factor 1, is also a growth factor in the CNS: Congenital absence of CSF‐1 in mice results in abnormal microglial response and increased neuron vulnerability to injury
Authors: Berezovskaya O. , Maysinger D. , Fedoroff S.
Published: July 2002

In this study we used op/op mice, which are deficient in the hematopoietic cytokine, colony‐stimulating factor 1 (CSF‐1), to determine the effect of CSF‐1 on neuronal survival and microglial response in injury. In normal mice microglia express the CSF‐1 receptor and are primarily regulated by CSF‐1, produced mainly by astrocytes. The CSF‐1 deficiency in op/op mice results in a depletion in the number of monocytes and macrophages but does not affect the number of morphology of microglia. We produced an ischemic lesion in the cerebral cortex of mice by disrupting the pia‐arachnoid blood vessels in a defined area. Using Nissl stain and strocyte‐ and microglia‐specific antibodies, we determined the number of viable neurons in such injury and the intensity of glial reaction. The cellular response to injury on the operated side of op/op mice was compared to that on the non‐operated contralateral side and to the cellular response in similar lesions in CSF‐1 producing C3H/HeJ mice. We found that the systemic lack of CSF‐1 in op/op mice results in a significant increase in neuron vulnerability to ischemic injury and considerably reduced microglial response to neuron injury. Remedying the CSF‐1 deficiency, either by grafting CSF‐1 secreting astroglia into the brain or by implanting encapsulated CSF‐1 secreting fibroblast‐like cells into the peritoneum, partially restores the microglial response to neuron injury and significantly potentiates neuronal survival in cerebral cortex ischemic lesions. Astroglial reaction was approximately the same in the lesions in op/op mice, grafted annd implanted op/op mice and C3H/HeJ mice, indicating that CSF‐1 modulates microglia, but not the response of astrocytes to injury. The degree of neuronal survival was not correlated to the degree of microglial proliferation and intensity of their reaction. We report some indications that CSF‐1, in addition to modulation of microglia, may also act directly on neurons.
GROWTH CONE BEHAVIOR IN THE PRESENCE OF SOLUBLE CHONDROITIN SULFATE PROTEOGLYCAN (CSPG), COMPARED TO BEHAVIOR ON CSPG BOUND TO LAMININ OR FIBRONECTIN
Authors: Snow Diane M. , Brown Eric M. , Letourneau Paul C.
Published: July 2002

Proteoglycans (PGs) are complex macromolecules of the extracellular matrix (ECM) that have a wide variety of effects on developing and regenerating neurons in vivo and in vitro. One hypothesis regarding the mechanisms of PG regulation of neuronal behavior states that the conformation of PGs may be critical, and thus that ECM‐ or cell surface‐bound PGs may operate differently than secreted (soluble) PGs. Therefore, this study examined differences between the effects of soluble chondroitin sulfate proteoglycan (CSPG) and substratum‐bound CSPG on neuronal growth cone behavior. Dissociated chicken dorsal root ganglion (DRG) neurons were cultured on either laminin (LN) or fibronectin (FN), both sensory neurite outgrowth‐promoting glycoproteins. CSPG (or chondroitin sulfate alone) was either bound to FN or LN, or was added to the culture media. Subsequently, using time lapse video microscopy and image analysis, this study measured: (1) neuronal attachment, (2) neurite outgrowth, (3) rate of neurite elongation, and (4) filopodial length and lifespan. To determine the site of CSPG action, DRG neurons were grown on either: CS‐1, a FN peptide [Humphries M. J. et al. (1987) J. biol. Chem. 262, 6886–6892], or a recombinant FN protein, RFNIIICS (Maejne, submitted), both of which permit DRG attachment and outgrowth but do not have recognized CSPG binding sites, and the resulting neuronal behavior was compared to that of DRG neurons grown on intact FN.

The results of these studies confirm that the effect of CSPG on DRG neurons is concentration‐, conformation‐ and substratum‐dependent. On LN, soluble CSPG had little to no effect on neurite initiation or outgrowth, while substratum‐bound CSPG inhibited neurite outgrowth. In contrast, on FN, soluble CSPG inhibited neurite outgrowth and decreased the rate of neurite elongation. Soluble CSPG did not affect the length of sensory growth cone filopodia or filopodial lifespan on either LN or FN. From the FN fragment experiments, we found that: (1) soluble CSPG reduces neurite outgrowth on FN or FN fragments, but not on LN, up to 80%, and reduces elongation rate on FN up to 50%, and (2) soluble CSPG regulates neuronal behavior by binding directly to growth cones elongating on FN.

Given that substratum‐bound CSPG from a variety of sources is inhibitory to neurite outgrowth and to the rate of neurite elongation, while soluble CSPG often has different effects on growth cone behavior, the regulation of growth cone behavior by CSPGs may be dependent upon CSPG conformation. Further, CSPG may affect growth cone behavior by either binding to the substratum or by binding directly to growth cones.
Receptor‐activated phospholipase D is present in caveolin‐3‐enriched light membranes of C2C12 myotubes
Authors: Meacci Elisabetta , Donati Chiara , Cencetti Francesca , Romiti Elena , Farnararo Marta , Bruni Paola
Published: July 2002

Caveolin‐3 (cav‐3) is a key structural component of caveolar membrane in skeletal muscle. Cav‐3‐enriched light membrane (CELM) fractions obtained from C2C12 myotubes contain phospholipase D1 (PLD1) and its major regulators, RhoA and protein kinase Cα (PKCα). All these proteins were found bound to cav‐3. An in vivo assay of PLD activity, which allows to localize the reaction product in CELMs, indicated that the enzyme associated to this membrane microdomain was active. Moreover, bradykinin (BK), thrombin and phorbol 12‐myristate 13‐acetate induced rapid stimulation of PLD activity in CELMs. The cav‐3‐PLD1 complex was not affected by BK treatment, whereas the agonist induced a marked increase of RhoA association with cav‐3. Furthermore, BK‐induced PLD activation in CELMs was dependent, at least in part, on PKCα.
The metal‐free hydrogenase from methanogenic archaea: evidence for a bound cofactor
Authors: Buurman Gerrit , Shima Seigo , Thauer Rudolf K
Published: July 2002

The hmd gene, which encodes the metal‐free hydrogenase in methanogenic archaea, was heterologously expressed in Escherichia coli. The overproduced enzyme was completely inactive. High activity could, however, be induced by the addition of ultrafiltrate from active enzyme denatured in 8 M urea. The active fraction in the ultrafiltrate was heat‐labile and migrated on gel filtration columns with an apparent molecular mass well below 1000 Da.
Immature human NT2 cells grafted into mouse brain differentiate into neuronal and glial cell types
Authors: Ferrari Alessandra , Ehler Elisabeth , Nitsch Roger M. , Götz Jürgen
Published: July 2002

NT2 cells are a transfectable human embryonal carcinoma cell line, that can be differentiated into postmitotic neuron‐like cells (NT2N cells), and transplanted into rodent brains. Differentiation requires a 5‐week‐long treatment with retinoic acid prior to transplantation. Here, we show that this step can be omitted, and that undifferentiated NT2 cells migrate over long distances and differentiate into both neuron‐ and oligodendrocyte‐like cell types upon grafting into brains of immunocompetent newborn mice. Grafted cells can be traced by fluorogold, with no evidence for tumor formation. Our approach provides an experimental model system which allows the immunohistological and biochemical study of neuronal and glial differentiation of human cells in vivo, and which may be suitable as an in vivo model for pharmacological studies.
Identification of essential aspartic acid and histidine residues of hormone‐sensitive lipase: apparent residues of the catalytic triad
Authors: Østerlund Torben , Contreras Juan Antonio , Holm Cecilia
Published: July 2002

© Federation of European Biochemical Societies.
Role of peroxide and superoxide anion during tumour cell apoptosis
Authors: Gorman Adrienne , McGowan Adrian , Cotter Thomas G.
Published: July 2002

© 1997 Federation of European Biochemical Societies.
cDNA cloning of Clavanins: antimicrobial peptides of tunicate hemocytes
Authors: Zhao Chengquan , Liaw Lilian , Hee Lee In , Lehrer Robert I
Published: July 2002

Clavanins are a family of α‐helical antimicrobial peptides found in hemocytes of the tunicate, Styela clava. We examined a cDNA library prepared from pharyngeal tissues of S. clava and sequenced 24 clones that encoded prepropeptides of Clavanins A, C, D or E. These sequences indicated that Clavanins are synthesized as 9.2 kDa prepropeptides which contain a 19‐residue signal peptide, followed in turn by a highly polar ‘pro’ region (LEERKSEEEK) with five glutamic acid residues, the 23 residues of the mature Clavanin peptide, the glycine residue needed for its amidation and a 27‐residue polar C‐terminal extension that is removed in later processing. Although the signal sequence and anionic propiece of Clavanin precursors share features with corresponding regions in precursors of the certain frog peptides, including ranalexin, gaegurins, dermaseptins and deltorphins, their unique multipartite structure suggests that they are not actually homologues of these amphibian peptides.
Inhibition of DNA synthesis and tube morphogenesis of cultured vascular endothelial cells by chondromodulin‐I
Authors: Hiraki Yuji , Kono Takaharu , Sato Mutsumi , Shukunami Chisa , Kondo Jun
Published: July 2002

Cartilage is an avascular tissue, and exhibits anti‐angiogenic properties. Cartilage extracts have been shown to contain an inhibitor for DNA synthesis in vascular endothelial cells in vitro. Here we purified the inhibitory activity in the 10–50 kDa fraction of guanidine extracts from fetal bovine epiphyseal cartilage, and found that the inhibitor was identical with chondromodulin‐I (ChM‐I). Purified ChM‐I inhibited tube morphogenesis of cultured vascular endothelial cells, as well as DNA synthesis. These results indicate that cartilage‐specific glycoprotein ChM‐I may participate in the maintenance of avascularity and anti‐angiogenic properties of cartilage.
Is the mammalian porin channel, VDAC, a perfect cylinder in the high conductance state?
Authors: Carneiro C.M.M , Krasilnikov O.V , Yuldasheva L.N , Campos de Carvalho A.C , Nogueira R.A
Published: July 2002

The mammalian porin channel (VDAC, porin‐31BM) was reconstituted in planar lipid bilayers under voltage clamp conditions. The radii of both entrances of the channel were examined using a method that consisted in filling the channel with different non‐electrolytes through its cis or trans entrances while recording single channel conductances. As a result it was found that the geometry of channels formed by porin‐31BM could not be approximated by a perfectly cylindrical pore. In fact there is an asymmetry in the geometry of the channel: the diameters of the cis and trans entrances were estimated to be ∼2 nm and ∼4 nm respectively.
Degradation of the 74 kDa form of l‐histidine decarboxylase via the ubiquitin‐proteasome pathway in a rat basophilic/mast cell line (RBL‐2H3)
Authors: Tanaka Satoshi , Nemoto Ken-ichi , Yamamura Eriko , Ohmura Satoshi , Ichikawa Atsushi
Published: July 2002

l‐Histidine decarboxylase (HDC) is a dimer consisting of two identical 53 kDa subunits. On the other hand, the size of HDC deduced from its cDNA sequence is around 74 kDa, indicating that the translated 74 kDa form of HDC is subjected to post‐translational processing to generate the 53 kDa form. However, modification of the translated 74 kDa form of HDC in histamine‐forming cells is unknown. Here we demonstrate that the 74 kDa form is translated in rat basophilic leukemia cells, followed by conversion to the 53 kDa form, and that the 74 kDa form is a short half‐life protein because of the degradation mediated by the ubiquitin‐proteasome pathway. Degradation of the 74 kDa form was stimulated in the presence of an ATP‐generating system, accompanied by ubiquitination, and inhibited by specific proteasome inhibitors such as ZL3H and lactacystin. A significant amount of proteasome activity was detected in RBL‐2H3 cells.
Structure, chromosome localization, and tissue distribution of the mouse twik K+ channel gene
Authors: Arrighi Isabelle , Lesage Florian , Scimeca Jean-Claude , Carle Georges F , Barhanin Jacques
Published: July 2002

We have recently discovered a new class of potassium channels with two pore‐forming domains and four membrane‐spanning domains. When heterologously expressed, these channels produce time‐ and voltage‐independent currents that classify them as background or leak channels. TWIK (for andem of P domains in a eak nwardly rectifying
+ channel) was the first member of this family to be cloned. Here, we describe the genomic organization of TWIK in the mouse. The coding sequence as well as the untranslated sequences are contained in three exons. The twik gene (or KCNK1) has been mapped to chromosome 8, consistent with its localization to 1q42–43 in human. The twik gene is expressed in virtually all mouse tissues. It is most abundantly expressed in brain and moderately in other organs such as kidney. The level of expression is increased in brain and kidney from neonate to adult animals, but the TWIK message is also detected during embryogenesis, as early as day 7 post conception.
Negative regulation of the anti‐human immunodeficiency virus and chemotactic activity of human stromal cell‐derived factor 1α by CD26/dipeptidyl peptidase IV
Authors: Ohtsuki Takashi , Hosono Osamu , Kobayashi Hiroshi , Munakata Yasuhiko , Souta Akiko , Shioda Tatsuo , Morimoto Chikao
Published: July 2002

Stromal cell‐derived factor 1α (SDF‐1α) is a chemokine that has been shown to prevent infection of T‐tropic HIV strains and is a possible substrate of CD26/dipeptidyl peptidase IV (DPPIV). In this study, we show that SDF‐1α was cleaved at the N‐terminal region by CD26/DPPIV and as a result the inhibitory activity of SDF‐1α against HIV infection disappeared. Moreover, the chemotactic activity of SDF‐1α also disappeared specifically by DPPIV activity of recombinant soluble CD26. These results suggested that dissemination of T‐tropic HIV strains in vivo may be facilitated by CD26/DPPIV via inactivation of functional SDF‐1α.
Thiol‐linked peroxidase activity of human ceruloplasmin
Authors: Kim In Gyu , Park Seon Young , Kim Kug Chan , Yum Jung Joo
Published: July 2002

Human ceruloplasmin exhibited different antioxidant effects according to the electron donors in a metal‐catalyzed oxidation system. Purified ceruloplasmin did not play a significant role in the protection of DNA strand breaks in the ascorbate/Fe3+/O2 system. However, when ascorbates were replaced with a thiol‐reducing equivalent such as dithiothreitol, DNA strand breaks were significantly prevented by the same amount of ceruloplasmin. Ceruloplasmin did not catalyze the decomposition of H2O2 in the absence of reduced glutathione. On the contrary, ceruloplasmin showed a potent peroxidase ability to destroy H2O2 in the presence of reduced glutathione. In conclusion, the removal of H2O2 by human ceruloplasmin is not simply stoichiometric but thiol‐dependent.
Single‐chain variable fragments selected on the 57–76 p21Ras neutralising epitope from phage antibody libraries recognise the parental protein
Authors: Persic Lidija , Horn Ivo R , Rybak Susanna , Cattaneo Antonino , Hoogenboom Hennie R , Bradbury Andrew
Published: July 2002

Phage antibodies have been widely prospected as an alternative to the use of monoclonal antibodies prepared by traditional means. Many monoclonal antibodies prepared against peptides are able to recognise the native proteins from which they were derived. Here we show that the same is also true for phage antibodies. We have selected a number of single‐chain variable fragments (scFv) from a large phage scFv library against a peptide from the switch region II of p21Ras. This peptide is known to reside in a mobile area of the native protein and is the epitope of a well characterised monoclonal antibody. Selected scFvs were able to recognise native p21Ras in both ELISA and Western blots, indicating that peptides are also likely to be very useful in selecting from phage antibody libraries.
Regulatory role of metallothionein in NF‐κB activation
Authors: Sakurai Atsuko , Hara Shuntaro , Okano Noriko , Kondo Yukihiro , Inoue Jun-ichiro , Imura Nobumasa
Published: July 2002

Metallothionein (MT), a low molecular weight, cysteine‐rich metal binding protein, has been associated with cytoprotection from heavy metals and cellular oxidants. As MT has the ability to scavenge hydroxyl radicals, MT may control intracellular redox status. In the present study, we examined whether MT regulates the activity of nuclear factor‐κB (NF‐κB), which is one of the redox‐regulated transcription factors, using the MT null embryonic cell lines established from MT null mice. We first found that tumor necrosis factor (TNF)‐induced activation of the binding of NF‐κB protein to DNA in wild type MT+/+ cells was lower than that in MT−/− cells. The NF‐κB activation in MT‐expressing cells established from MT−/− cells by the transfection of mouse MT‐I gene was also significantly lower than that in MT−/− cells. In addition, transfection of the MT gene inhibited TNF‐induced IκB degradation and suppressed NF‐κB‐dependent gene expression induced by TNF. These results demonstrate that MT may function as a negative regulator of NF‐κB activity.
Computational modeling of the rate limiting step in low molecular weight protein tyrosine phosphatase
Authors: Kolmodin Karin , Åqvist Johan
Published: July 2002

Hydrolysis of the phosphoenzyme intermediate is the second and rate limiting step of the reaction catalyzed by the protein tyrosine phosphatases (PTPs). The cysteinyl phosphate thioester bond is cleaved by nucleophilic displacement where an active site water molecule attacks the phosphorus atom. Starting from the crystal structure of the low molecular weight PTP, we study the energetics of this reaction utilizing the empirical valence bond method in combination with molecular dynamics and free energy perturbation simulations. The reactions of the wild‐type as well as the D129A and C17S mutants are modeled. For the D129A mutant, which lacks the general acid/base residue Asp‐129, an alternative reaction mechanism is proposed. The calculated activation barriers are in all cases in good agreement with experimental reaction rates. The present results together with earlier computational and experimental work now provide a detailed picture of the complete reaction mechanism in many PTPs. The key role played by the structurally invariant signature motif in stabilizing a double negative charge is reflected by its control of the energetics of both transition states and the reaction intermediate.
Overexpression of a designed 2.2 kb gene of eukaryotic phenylalanine ammonia‐lyase in Escherichia coli
Authors: Baedeker Mathias , Schulz Georg E
Published: July 2002

Phenylalanine ammonia‐lyase (EC 4.3.1.5) is a key enzyme in the secondary metabolism of higher plants catalyzing the non‐oxidative conversion of L‐phenylalanine into trans‐cinnamate. The nucleotide sequence of its 2.2 kb gene was designed for expression in Escherichia coli and synthesized in a single reaction from 108 oligonucleotides using assembly PCR. After amplification, the gene was cloned into the expression vector pT7‐7 and coexpressed with the chaperone HSP‐60 system. The expression system yielded 70 mg of fully active enzyme per liter culture.
Receptor‐mediated activation of phospholipase D by sphingosine 1‐phosphate in skeletal muscle C2C12 cells
Authors: Meacci Elisabetta , Vasta Valeria , Donati Chiara , Farnararo Marta , Bruni Paola
Published: July 2002

The present study showed that sphingosine 1‐phosphate (SPP) induced rapid stimulation of phospholipase D (PLD) in skeletal muscle C2C12 cells. The effect was receptor‐mediated since it was fully inhibited by pertussis toxin. All known SPP‐specific receptors, Edg‐1, Edg‐3 and AGR16/H218, resulted to be expressed in C2C12 myoblasts, although at a different extent. SPP‐induced PLD activation did not involve membrane translocation of PLD1 or PLD2 and appeared to be fully dependent on protein kinase C (PKC) catalytic activity. SPP increased membrane association of PKCα, PKCδ and PKCλ, however, only PKCα and PKCδ played a role in PLD activation since low concentrations of GF109203X and rottlerin, a selective inhibitor of PKCδ, prevented PLD stimulation.
Molecular cloning of newt sex pheromone precursor cDNAs: evidence for the existence of species‐specific forms of pheromones
Authors: Iwata T. , Umezawa K. , Toyoda F. , Takahashi N. , Matsukawa H. , Yamamoto K. , Miura S. , Hayashi H. , Kikuyama S.
Published: July 2002

Cloning of cDNA encoding a decapeptide pheromone (sodefrin) that attracts conspecific female newts was attempted. A cDNA clone encoding a protein consisting of 189 amino acid residues including a sodefrin sequence was isolated from a Cynops pyrrhogaster abdominal gland cDNA library. Likewise, a cDNA clone encoding a molecule comparable to the sodefrin precursor was obtained from a Cynops ensicauda abdominal gland cDNA library. This clone encoded a precursor protein of 192 amino acid residues, including a sodefrin‐like peptide sequence with substitutions of two amino acid residues. This is the first report of a peptide pheromone precursor in vertebrates.
A one year prevalence study of schizophrenia on Reunion Island
Authors: Jay M , Gorwood P , Feingold J , Leboyer M
Published: July 2002

Review of geographical comparisons of the prevalence of schizophrenic disorders found a ten-fold range difference between geographical contiguous groups, with high and low prevalence pockets. We performed a 1-year prevalence study of schizophrenia in a limited area of Reunion Island in the Indian Ocean, and analysed the prevalence variability in contiguous regions of this area. We found one of the highest reported age-corrected (above 15 years) 1-year prevalence of schizophrenia (14.9 per thousand). Large discrepancies in the distribution of prevalence rates of schizophrenia were observed between the five towns analysed. Interestingly, when a higher prevalence was observed, it was highly correlated with an increase of the percentage of familial cases (r = 0.989, df = 3, P = 0.0014). Presence of founder effect often described in geographical isolates could explain the high prevalence rate and the heterogeneity between towns observed in our sample.
Social anxiety in insulin-dependent diabetic girls
Authors: Vera L , Nollet-Clémençon C , Vila G , Mouren-Siméoni MC , Robert JJ
Published: July 2002

The purpose of this study was to investigate the relationship of social anxiety and insulin-dependent diabetes mellitus (n = 40 girls between 13 and 19 years of age). Mean duration of diabetes was 7 years. We supposed that this chronic illness may provoke feelings of friendlessness and sadness, social withdrawal and fear of social situations because diabetes entails a series of demands which differentiate the diabetic child from healthy children. Our population was compared with 35 healthy young girls. All were administered the Schedule for Affective Disorders and Schizophrenia for School-Age-Children and completed the State Trait Anxiety Inventory for Children, the Self-Consciousness Scale and the Imaginary Audience Scale. Diagnoses of anxiety disorders across DSM-IIIR do not show significant differences between groups. In self-report inventories, our findings do not support the hypothesis that social anxiety is a pathological symptom in diabetic subjects. However, they were more depressed than the control group. Furthermore, social functioning of the diabetic group did not differ from that of the control group. They were more concerned with their illness than with social anxiety.
Prefoldin subunit 6 of Plasmodium falciparum binds merozoite surface protein‐1
Authors: Kumar Vikash , Shoaib Rumaisha , Behl Ankita , Munjal Akshay , Abid Mohammad , Singh Shailja
Published: November 2020

Malaria is a human disease caused by eukaryotic protozoan parasites of the Plasmodium genus. Plasmodium falciparum (Pf) causes the most lethal form of human malaria and is responsible for widespread mortality worldwide. Prefoldin is a heterohexameric molecular complex that binds and delivers unfolded proteins to chaperonin for correct folding. The prefoldin PFD6 is predicted to interact with merozoite surface protein‐1 (MSP‐1), a protein well known to play a pivotal role in erythrocyte binding and invasion by Plasmodium merozoites. We previously found that the P. falciparum (Pf) genome contains six prefoldin genes and a prefoldin‐like gene whose molecular functions are unidentified. Here, we analyzed the expression of PfPFD‐6 during the asexual blood stages of the parasite and investigated its interacting partners. PfPFD‐6 was found to be significantly expressed at the trophozoite and schizont stages. Pull‐down assays suggest PfPFD‐6 interacts with MSP‐1. In silico analysis suggested critical residues involved in the PfPFD‐6‐MSP‐1 interaction. Our data suggest PfPFD‐6 may play a role in stabilizing or trafficking MSP‐1.
Semantic Change
Authors: Geeraerts Dirk
Published: November 2020

This chapter covers the main mechanisms of semantic change, with a focus on word meaning. After introducing the distinction between semasiological and onomasiological, and that between referential and semantic change, processes of change are classified at three different levels: the level of senses, of words, and of the vocabulary as a whole. The chapter rounds off with a discussion of how contemporary corpus linguistics provides a new impetus for diachronic semantics.
Nusinersen in type 0 spinal muscular atrophy: should we treat?
Authors: Tiberi Eloisa , Costa Simonetta , Pane Marika , Priolo Francesca , de Sanctis Roberto , Romeo Domenico , Tiziano Francesco D. , Conti Giorgio , Vento Giovanni , Mercuri Eugenio
Published: November 2020

A male infant affected by type 0 SMA with one copy of SMN2 received early treatment with Nusinersen at the age of 13 days. He showed mild motor improvement 2 months after treatment started but despite also showing some minimal respiratory improvement, required tracheostomy at the age of 4 months and had increasing cardiac and autonomic dysfunction leading to exitus at 5 months. Our findings, expanding the results available on Nusinersen, confirm its relative efficacy in the most severely affected infants and provide clinical evidence to be used at the time requests for treating severe infants are discussed.
Lightweight Self‐Forming Super‐Elastic Mechanical Metamaterials with Adaptive Stiffness
Authors: Wu Rui , Roberts Peter C. E. , Lyu Shida , Zheng Fei , Soutis Constantinos , Diver Carl , Zhou Dekai , Li Longqiu , Deng Zongquan
Published: November 2020

Scarcity of stiff, yet compliant, materials is a major obstacle toward biological‐like mechanical systems that perform precise manipulations while being resilient under excessive load. A macroscopic cellular structure comprising two pre‐stressed elastic “phases” is introduced, which displays a load‐sensitive stiffness that drops by 30 times upon a “pseudoductile transformation” and accommodates a fully recoverable compression of over 60%. This provides an exceptional 20 times more deformability beyond the linear‐elastic regime, doubling the capability of previously reported super‐elastic materials. In virtue of the pre‐stressing process based on thermal‐shrinkage, it simultaneously enables a heat‐activated self‐formation that transforms a flat laminate into the metamaterial with 50 times volumetric growth. The metamaterial is thereby inherently lightweight with a bulk density in the order of 0.01 g cm−3, which is one order of magnitude lower than existing super‐elastic materials. Besides the highly programmable geometrical and mechanical characteristics, this paper is the first to present a method that generates single‐crystal or poly‐crystal‐like 3D lattices with anisotropic or isotropic super‐elasticity. This pre‐stress‐induced adaptive stiffness with high deformability could be a step toward in situ deployed ultra‐lightweight mechanical systems with a diverse range of applications that benefit from being stiff and compliant.
Biomimetic Nanomaterial Strategies for Virus Targeting: Antiviral Therapies and Vaccines
Authors: Jackman Joshua A. , Yoon Bo Kyeong , Ouyang Lei , Wang Nan , Ferhan Abdul Rahim , Kim Jaeyun , Majima Tetsuro , Cho Nam‐Joon
Published: November 2020

The ongoing coronavirus disease 2019 (COVID‐19) pandemic highlights the importance of developing effective virus targeting strategies to treat and prevent viral infections. Since virus particles are nanoscale entities, nanomaterial design strategies are ideally suited to create advanced materials that can interact with and mimic virus particles. In this progress report, the latest advances in biomimetic nanomaterials are critically discussed for combating viral infections, including in the areas of nanomaterial‐enhanced viral replication inhibitors, biomimetic virus particle capture schemes, and nanoparticle vaccines. Particular focus is placed on nanomaterial design concepts and material innovations that can be readily developed to thwart future viral threats. Pertinent nanomaterial examples from the COVID‐19 situation are also covered along with discussion of human clinical trial efforts underway that might lead to next‐generation antiviral therapies and vaccines.
Monocrystalline Antimonene Nanosheets via Physical Vapor Deposition
Authors: Kuriakose Sruthi , Jain Shubhendra Kumar , Tawfik Sherif A. , Spencer Michelle J. S. , Murdoch Billy J. , Singh Mandeep , Rahman Fahmida , Mayes Edwin L. H. , Taha Mohammad Yousef , Ako Rajour Tanyi , Bansal Vipul , Ahmed Taimur , Sriram Sharath , Bhaskaran Madhu , Balendhran Sivacarendran , Walia Sumeet
Published: November 2020

Among the family of elemental 2D materials, antimonene is predicted to have a desirable combination of bandgap tunability and exceptional physical properties. However, there is a lack of a facile synthesis technique to prepare high‐quality antimonene with large aspect ratios on standard SiO2 substrates, hindering wide scale exploration of this material. Here, a physical vapor deposition process to controllably achieve millimeter‐scale, β‐phase, monocrystalline antimonene nanosheets on a SiO2 dielectric substrate is reported. The temperature gradient across the deposition tube is exploited to realize either large‐area nanosheets or single antimonene crystals on‐demand. The composition and quality of the nanosheets and crystals is assessed using spectroscopy, diffraction, and microscopy techniques which suggest the formation of the β‐phase allotrope. The band structure of as‐synthesized nanosheets which matches the theoretically calculated values is experimentally extracted. Finally, contrary to earlier reports, the oxidation of antimonene under ambient conditions over a period of time indicating the need for further experimental studies of the material's stability is revealed. The reported controllable growth of antimonene nanosheets and single crystals on conventional dielectric substrates opens a spectrum of possible applications of this material in electronics and optoelectronics devices.
Photonic Bound States in the Continuum: From Basics to Applications
Authors: Azzam Shaimaa I. , Kildishev Alexander V.
Published: November 2020

The introduction of bound states in the continuum (BICs) to photonics has revolutionized the way cavity design and light–matter interactions are thought about in general. BICs can have very high quality factors, even in open structures where access to radiation is permissible. Now, BICs found applications in a large class of areas, including nonlinear enhancement, coherent light generation, sensors, filters, integrated circuits, and many others. In this review, the different types of BICs in photonic systems, as well as their physics and formation mechanisms are briefly overviewed. The rest of the review focuses on the current and emerging applications of photonic BICs and their role in shaping the interaction of light and matter.
Regioselective and Chemodivergent Synthesis of Azulenolactones and Azulenolactams from Rhodium(III)‐Catalyzed Reactions of Azulenecarboxamides with Sulfoxonium Ylides
Authors: Lee Seung Cheol , Son Jeong‐Yu , Kim Jin Young , Eom Hyeonsik , Jang Seong Bin , Lee Phil Ho
Published: November 2020

A regioselective and chemodivergent synthetic approach for azulenolactones and azulenolactams as a new scaffold was demonstrated through Rh(III)‐catalyzed reaction of N‐methoxyazulene‐1‐carboxamides with sulfoxonium ylides. Sulfoxonium ylides that act as a precursor of secondary carbene was described, leading to the selective formation of azulenolactones and azulenolactams bearing two substituents on a newly introduced double bond. This method demonstrated functionalization of less reactive 2‐position of azulene to overcome the natural reactivity.

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Injectable Thermosensitive Hydrogel Containing Erlotinib‐Loaded Hollow Mesoporous Silica Nanoparticles as a Localized Drug Delivery System for NSCLC Therapy
Authors: Zhou Xiaohan , He Xinlong , Shi Kun , Yuan Liping , Yang Yun , Liu Qingya , Ming Yang , Yi Cheng , Qian Zhiyong
Published: November 2020

Erlotinib (ERT), oral administration agents, is one of the most pivotal targeted drugs in the treatment of non‐small cell lung cancer (NSCLC); however, its poor solubility, low oral bioavailability, and capricious toxicity limit broader clinical applications. In this paper, a novel injectable matrix is prepared based on hollow mesoporous silica nanoparticles (HMSNs) and thermosensitive poly(d,l‐lactide)‐poly(ethylene glycol)‐poly(d,l‐lactide) (PDLLA‐PEG‐PDLLA, PLEL) hydrogel to encapsulate and localize the sustained release of ERT for improved efficacy against NSCLC. The test‐tube‐inversion method shows that this ERT‐loaded hydrogel composite (ERT@HMSNs/gel) presents as an injectable flowing solution under room temperature and transfers into a physically crosslinked non‐flowing gel structure at physiological temperature.The ERT@HMSNs/gel composite shows a much longer intratumoral and peritumoral drug retention by in vivo imaging study. Notably, this injectable drug delivery system (DDS) provides an impressive balance between antitumor efficacy and systemic safety in a mice xenograft model. The novel ERT loaded HMSNs/gel system may be a promising candidate for the in situ treatment of NSCLC. Moreover, this study provides a prospective platform for the design and fabrication of a nano‐scaled delivery system for localized anticancer therapies.
LiDFOB Initiated In Situ Polymerization of Novel Eutectic Solution Enables Room‐Temperature Solid Lithium Metal Batteries
Authors: Wu Han , Tang Ben , Du Xiaofan , Zhang Jianjun , Yu Xinrun , Wang Yantao , Ma Jun , Zhou Qian , Zhao Jingwen , Dong Shanmu , Xu Gaojie , Zhang Jinning , Xu Hai , Cui Guanglei , Chen Liquan
Published: November 2020

It is demonstrated that a novel eutectic solution including 1,3,5‐trioxane (TXE) and succinonitrile (SN) can be converted into solid‐state polymer electrolyte (SPE) via in situ polymerization triggered by lithium difluoro(oxalato)borate (LiDFOB). It is worth noting that all the precursors (LiDFOB, TXE, and SN) of this novel SPE are totally solid and nonvolatile at room temperature, where, LiDFOB works as a lithium salt and an initiator simultaneously to avoid the introduction of impurity. It is noted that such SPE presents a considerable ionic conductivity of 1.14 × 10−4 S cm−1 and a sufficiently wide electrochemical window of 4.5 V, which is significant for supporting the high‐energy lithium batteries. In addition, this dedicatedly designed in situ polymerization is powerful to build kinetically favorable polymer‐based protective layers on LiCoO2 cathode and Li metal anode simultaneously, guaranteeing outstanding cycling stability (capacity retention of 88% after 200 cycles) of 4.3 V LiCoO2/lithium metal batteries at room temperature. More intriguingly, soft packed LiCoO2/SPE/Li metal batteries can still light a blue light emitting diode (LED) under the harsh conditions of being bent, cut, and stroked by a hammer, demonstrating excellent safety characteristics.
Prey exclusion combined with simulated fire increases subsequent prey‐capture potential in the pale pitcher plant, Sarracenia alata
Authors: Abbott Matthew J. , Brewer J. Stephen
Published: November 2020

Premise

The association of carnivory (an adaptation to nutrient‐poor soils) with fire has been described as a paradox, given increases in nutrient availability that often accompany fire. The nutrients that increase in availability following fire, however, may not be the same as those provided by prey and may not reduce nutrient limitation if accompanied by even greater increases in light.

Methods

Using a factorial experiment in the field, we examined how simulated fire (clipping plus nitrogen‐free fertilizer addition) and prey‐derived nutrient availability (prey exclusion) interacted to influence carnivorous potential in Sarracenia alata and belowground competition with its neighbors (manipulated via trenching). We hypothesized that simulated fire combined with prey exclusion would (1) increase the potential for prey capture relative to shade avoidance, hereafter, relative prey‐capture potential (RPCP), and/or (2) increase belowground competition with neighboring plants.

Results

Sarracenia alata increased RPCP in response to the combination of simulated fire and prey exclusion, despite increases in phosphorus and other nutrients associated with the simulated fire treatment, suggesting that prey capture potential increases in response to increased nitrogen limitation resulting from increases in light and/or phosphorus after fire. We found no evidence of belowground competition.

Conclusions

The potential importance of carnivory in Sarracenia alata increases following fire. This result helps to explain the paradoxical association of carnivorous plants with fire by demonstrating the potential for prey‐derived nutrient limitation to increase rather than decrease in response to increases in light and nutrients other than nitrogen following fire.