bluuebunny/crossref_metadata_2025_split huggingface dataset:
‘Well, have I got cancer or haven't I?’ The psycho‐social issues for women diagnosed with ductal carcinoma in situ
Authors: De Morgan Simone , Redman Sally , White Kate J , Cakir Burcu , Boyages John 
Published: March 2003

AbstractObjectives  To explore women's experience of being diagnosed with ductal carcinoma in situ (DCIS) in relation to the following: response to the diagnosis; understanding about the diagnosis; satisfaction with information; satisfaction with the level of involvement in treatment decision‐making and satisfaction with support services.Design  An explorative descriptive qualitative design was used to facilitate an in‐depth exploration of women's experiences.Setting and participants  Five focus group interviews were conducted in New South Wales (NSW), Australia, involving 26 women diagnosed with DCIS.Results  DCIS is a non‐invasive breast disease, that in most cases will not recur if treated, and cannot of itself metastasize to other parts of the body. However, this study found that women were confused about whether or not they had cancer that could result in death. Women's confusion was compounded by the use of the term ‘carcinoma’ and by the recommendation of treatments such as mastectomy. Women's confusion was not alleviated by appropriate information, with most women reporting dissatisfaction with the information they received specifically about DCIS.Conclusions  This study identifies that a diagnosis of DCIS has a significant psychological impact on women. The communication challenges highlighted in this study are not only relevant to DCIS but to any other disease in which the natural history is uncertain and the evidence about treatment effectiveness is still emerging. Further research is needed in areas such as DCIS to explore the difficulties experienced in doctor–patient communication and their impact on patient outcomes, and how to optimize doctor–patient communication.
The effects of low pH on the properties of protochlorophyllide oxidoreductase and the organization of prolamellar bodies of maize (Zea mays)
Authors: Selstam Eva , Schelin Jenny , Brain Tony , Williams W. Patrick 
Published: March 2003

Prolamellar bodies (PLB) contain two photochemically active forms of the enzyme protochlorophyllide oxidoreductase POR‐PChlide640 and POR‐PChlide650 (the spectral forms of POR‐Chlide complexes with absorption maxima at the indicated wavelengths). Resuspension of maize PLB in media with a pH below 6.8 leads to a rapid conversion of POR‐PChlide650 to POR‐PChlide640 and a dramatic re‐organization of the PLB membrane system. In the absence of excess NADPH, the absorption maximum of the POR complex undergoes a further shift to about 635 nm. This latter shift is reversible on the re‐addition of NADPH with a half‐saturation value of about 0.25 mm NADPH for POR‐PChlide640 reformation. The disappearance of POR‐PChlide650 and the reorganization of the PLB, however, are irreversible. Restoration of low‐pH treated PLB to pH 7.5 leads to a further breakdown down of the PLB membrane and no reformation of POR‐PChlide650. Related spectral changes are seen in PLB aged at room temperature at pH 7.5 in NADPH‐free assay medium. The reformation of POR‐PChlide650 in this system is readily reversible on re‐addition of NADPH with a half‐saturation value about 1.0 µm. Comparison of the two sets of changes suggest a close link between the stability of the POR‐PChlide650, membrane organization and NADPH binding.The low‐pH driven spectral changes seen in maize PLB are shown to be accelerated by adenosine AMP, ADP and ATP. The significance of this is discussed in terms of current suggestions of the possible involvement of phosphorylation (or adenylation) in changes in the aggregational state of the POR complex.
Interaction between p21‐activated protein kinase and Rac during differentiation of HL‐60 human promyelocytic leukemia cell induced by all‐trans‐retinoic acid
Authors: Nisimoto Yukio , Ogawa Hisamitsu 
Published: March 2003

Undifferentiated human promyelocytic leukemia HL‐60 cells show little or no superoxide production, but generate a very low O2– concentration upon incubation with all‐trans‐retinoic acid (ATRA). Its production reaches a maximum within 20 h, and thereafter is maintained at an almost constant level. The differentiated cells show phorbol 12‐myristate 13‐acetate (PMA)‐stimulated NADPH oxidase activity consistent with the amount of gp91phox (phagocytic oxidase) expressed in the plasma membrane. Three isoforms of p21‐activated serine/threonine kinases, PAK68, PAK65 and PAK62, were found in both cytosolic and membrane fractions, and their contents were significantly increased during induced differentiation. The amount of Rac identified in the two fractions was also markedly enhanced by ATRA‐	induced differentiation. In contrast, neither PAK nor Rac was seen in the plasma membrane of undifferentiated HL‐60 or human neutrophil, but they were abundant in the cytoplasmic fraction. Binding of Rac with PAK isoforms was shown in the membrane upon induced differentiation of HL‐60 cells. Direct binding of purified Rac1 to PAK68 was quantified using a fluorescent analog of GTP (methylanthraniloyl guanosine‐5′‐[β,γ‐imido]triphosphate) bound to Rac as a reporter group. Rac1 bound to PAK68 with a 1 : 1 stoichiometry and with a Kd value of 6.7 nm.
Thermolysin‐linearized microcin J25 retains the structured core of the native macrocyclic peptide and displays antimicrobial activity
Authors: Blond Alain , Cheminant Michel , Destoumieux‐Garzón Delphine , Ségalas‐Milazzo Isabelle , Peduzzi Jean , Goulard Christophe , Rebuffat Sylvie 
Published: March 2003

Microcin J25 (MccJ25) is the single macrocyclic antimicrobial peptide belonging to the ribosomally synthesized class of microcins that are secreted by Enterobacteriaceae. It showed potent antibacterial activity against several Salmonella and Escherichia strains and exhibited a compact three‐dimensional structure [Blond et al. (2001) Eur. J. Biochem., 268, 2124–2133]. The molecular mechanisms involved in the biosynthesis, folding and mode of action of MccJ25 are still unknown. We have investigated the structure and the antimicrobial activity of thermolysin‐linearized MccJ25 (MccJ25‐L1−21: VGIGTPISFY10GGGAGHVPEY20F), as well as two synthetic analogs, sMccJ25‐L1−21 (sequence of the thermolysin‐cleaved MccJ25) and sMccJ25‐L12−11 (C‐terminal sequence of the MccJ25 precursor: G12GAGHVPEYF21V1GIGTPISFYG11). The three‐dimensional solution structure of MccJ25‐L1−21, determined by two‐dimensional NMR, consists of a boot‐shaped hairpin‐like well‐defined 8–19 region flanked by disordered N and C termini. This structure is remarkably similar to that of cyclic MccJ25, and includes a short double‐stranded antiparallel β‐sheet (8–10/17–19) perpendicular to a loop (Gly11–His16). The thermolysin‐linearized MccJ25‐L1−21 had antibacterial activity against E. coli and S. enteritidis strains, while both synthetic analogues lacked activity and organized structure. We show that the 8–10/17–19 β‐sheet, as well as the Gly11–His16 loop are required for moderate antibacterial activity and that the Phe21–Pro6 loop and the MccJ25 macrocyclic backbone are necessary for complete antibacterial activity. We also reveal a highly stable 8–19 structured core present in both the native MccJ25 and the thermolysin‐linearized peptide, which is maintained under thermolysin treatment and resists highly denaturing conditions.
Human aldehyde dehydrogenase gene family
Authors: Yoshida Akira , Rzhetsky Andrey , Hsu Lily C. , Chang Cheng 
Published: March 2003

Twelve aldehyde dehydrogenase (ALDH) genes have been identified in humans. These genes, located on different chromosomes, encode a group of enzymes which oxidizes varieties of aliphatic and aromatic aldehydes. Metabolic disorders and clinical problems associated with mutations of ALDH1, ALDH2, ALDH4, ALDH10 and succinic semialdehyde (SSDH) genes have been emerged. Comparison of the human ALDHs indicates a wide range of divergency (> 80−< 15 % identity at the protein sequence level) among them. However, several protein regions, some of which are implicated in functional activities, are conserved in the family members.The phylogenic tree constructed of 56 ALDH sequences of humans, animals, fungi, protozoa and eubacteria, suggests that the present‐day human ALDH genes were derived from four ancestral genes that existed prior to the divergence of Eubacteria and Eukaryotes. The neighbor‐joining tree derived from 12 human ALDHs and antiquitin indicates that diversification within the ALDH1/2/5/6 gene cluster occurred during the Neoproterozoic period (about 800 million years ago). Duplication in the ALDH 3/10/7/8 gene cluster occurred in Phanerozoic period (about 300 million years ago). Separations of ALDH3/ALDH10 and that of ALDH7/ALDH8 had occurred during the period of appearance and radiation of mammalian species.
Glycyl‐tRNA synthetase from Thermus thermophilus
Authors: Mazauric Marie‐Hélène , Keith Gérard , Logan Derek , Kreutzer Roland , Giegé Richard , Kern Daniel 
Published: March 2003

The tRNA glycylation system is amongst the most complex aminoacylation systems since neither the oligomeric structure of the enzymes nor the discriminator base in tRNAs are conserved in the phylae. To understand better this structural diversity and its functional consequences, the prokaryotic glycylation system from Thermus thermophilus, an extreme thermophile, was investigated and its structural and functional inter‐relations with those of other origins analyzed. Alignments of the protein sequence of the dimeric thermophilic glycyl‐tRNA synthetase (Gly‐tRNA synthetase) derived from its gene with sequences of other dimeric Gly‐tRNA synthetases revealed an atypical character of motif 1 in all these class 2 synthetases. Interestingly, the sequence of the prokaryotic thermophilic enzyme resembles eukaryotic and archaebacterial Gly‐tRNA synthetases, which are all dimeric, and diverges drastically from the tetrameric enzymes from other prokaryotes.Cross aminoacylations with tRNAs and synthetases of different origins provided information about functional interrelations between the glycylation systems. Efficient glycylations involving partners from T. thermophilus and Escherichia coli showed conservation of the recognition process in prokaryotes despite strong structural variations of the synthetases. However, Gly‐tRNA synthetase from T. thermophilus acylates eukaryotic tRNAGly while the charging ability of the E. coli enzyme is restricted to prokaryotic tRNAGly. A similar behaviour is found in eukaryotic systems where the restricted species specificity for tRNA glycylation of mammalian Gly‐tRNA synthetase contrasts with the relaxed specificity of the yeast enzyme. The consensus sequence of the tRNAs charged by the various Gly‐tRNA synthetases reveals conservation of only G1−C72 in the acceptor arm, C35 and C36 in the anticodon, and the (G10−Y25)‐G45 triplet involved in tRNA folding. Conservation of these nucleotides indicates their key role in glycylation and suggests that they were part of the ancestral glycine identity set.These features are discussed in the context of the phylogenic connections between prokaryotes, eukaryotes, and archaebacteria, and of the particular place of T. thermophilus in this phylogeny.
Mitochondria and apoptosis
Authors: Mignotte Bernard , Vayssiere Jean‐Luc 
Published: March 2003

Programmed cell death serves as a major mechanism for the precise regulation of cell numbers and as a defense mechanism to remove unwanted and potentially dangerous cells. Despite the striking heterogeneity of cell death induction pathways, the execution of the death program is often associated with characteristic morphological and biochemical changes, and this form of programmed cell death has been termed apoptosis.Genetic studies in Caenorhabditis elegans had led to the identification of cell death genes (ced). The genes ced‐3 and ced‐4 are essential for cell death; ced‐9 antagonizes the activities of ced‐3 and ced‐4, and thereby protects cells that should survive from any accidental activation of the death program. Caspases (cysteine aspartases) are the mammalian homologues of CED‐3. CED‐9 protein is homologous to a family of many members termed the Bcl‐2 family (Bcl‐2s) in reference to the first discovered mammalian cell death regulator. In both worm and mammalian cells, the antiapoptotic members of the Bcl‐2 family act upstream of the execution caspases somehow preventing their proteolytic processing into active killers.Two main mechanisms of action have been proposed to connect Bcl‐2s to caspases. In the first one, antiapoptotic Bcl‐2s would maintain cell survival by dragging caspases to intracellular membranes (probably the mitochondrial membrane) and by preventing their activation. The recently described mammalian protein Apaf‐1 (apoptosis protease‐activating factor 1) could be the mammalian equivalent of CED‐4 and could be the physical link between Bcl‐2s and caspases. In the second one, Bcl‐2 would act by regulating the release from mitochondria of some caspases activators : cytochrome c and/or AIF (apoptosis‐inducing factor). This crucial position of mitochondria in programmed cell death control is reinforced by the observation that mitochondria contribute to apoptosis signaling via the production of reactive oxygen species. Although for a long time the absence of mitochondrial changes was considered as a hallmark of apoptosis, mitochondria appear today as the central executioner of programmed cell death. In this review, we examine the data concerning the mitochondrial features of apoptosis. Furthermore, we discuss the possibility that the mechanism originally involved in the maintenance of the symbiosis between the bacterial ancestor of the mitochondria and the host cell precursor of eukaryotes, provided the basis for the actual mechanism controlling cell survival.
Purification and characterization of N‐acetylglucosamine kinase from rat liver
Authors: Hinderlich Stephan , Nöhring Sabine , Weise Christoph , Franke Peter , Stäsche Roger , Reutter Werner 
Published: March 2003

N‐Acetylglucosamine, a major sugar in complex carbohydrates, enters the pathways of aminosugar metabolism by the action of N‐acetylglucosamine kinase (
EC2.7.1.59). In this study we report the purification to homogeneity of GlcNAc kinase from rat liver cytosol using salmine sulfate precipitation, chromatography on phenyl‐Sepharose, ATP‐agarose and MonoQ, and finally gel filtration on Superdex 200. It was characterized as a dimer of 39‐kDa subunits. About 25 % of the amino acid sequence of GlcNAc kinase was established by peptide mapping. Part of the ATP‐binding site of GlcNAc kinase was identified by sequence comparison with related hexokinases, including the bifunctional enzyme UDP‐N‐acetylglucosamine 2‐epimerase/N‐acetylmannosamine kinase (
EC5.1.3.14/2.7.1.60), the key enzyme of N‐acetylneuraminic acid biosynthesis in rat liver.The Cys residues in the active sites of GlcNAc kinase and ManNAc kinase were characterized by chemical modification with N‐ethylmaleimide, iodoacetamide and 5,5′‐dithiobis(2‐nitrobenzoic acid). The finding that the substrates GlcNAc and ManNAc protected their respective enzymes from inhibition by the above sulfhydryl reagents indicates that Cys residues are located in or near the active sites of both enzymes. Use of the specific dithiol‐modifying chemical reagents, sodium meta‐periodate, sodium meta‐arsenite/2,3‐dimercaptopropanol and diazenedicarboxylic acid bis‐N,N′‐dimethylamide revealed that the active sites of GlcNAc kinase and ManNAc kinase possess at least one pair of vicinal thiols. Chemical treatment of UDP−GlcNAc 2‐epimerase provided no evidence for the presence of cysteine in the active site of this enzyme. From the incorporation of N‐[3H]ethylmaleimide into GlcNAc kinase in the absence and presence of ligands we estimated that the active site of GlcNAc kinase contains two Cys residues.
Cloning of two cDNAs encoding three small serine protease inhibiting peptides from the desert locust Schistocerca gregaria and analysis of tissue‐dependent and stage‐dependent expression
Authors: Vanden Broeck Jozef , Chiou Shean‐Jaw , Schoofs Liliane , Hamdaoui Ahmed , Vandenbussche Frank , Simonet Gert , Wataleb Said , De Loof Arnold 
Published: March 2003

This study describes the cloning of two cDNAs encoding three serine‐protease‐inhibiting peptides, SGPI I, II and III, which were recently identified from ovarian extracts of the desert locust, Schistocerca gregaria. The first cDNA codes for the precursor polypeptides of SGPI I and SGPI II; the second encodes only a single inhibitor, SGPI III.Northern‐blot analysis revealed an approximate length of 0.8 kb for SGPI‐I/II mRNA and 0.6 kb for SGPI‐III mRNA. The transcripts are present in several locust tissues, but they could not be detected in the midgut. The gene for SGPI‐I/II is abundantly transcribed during all larval and adult stages, whereas SGPI‐III mRNA is mainly present in adults. Northern‐blot hybridization also revealed important changes in the SGPI‐mRNA content during the molting cycle and during the adult reproductive cycle. Moreover, a differential hormonal control was observed in adult females which had been treated with precocene, juvenile hormone or ecdysone.
Competition and cooperation amongst yeast elongation factors
Authors: Kovalchuke Oleh , Kambampati Ravi , Pladies Erika , Chakraburtty* Kalpana 
Published: March 2003

Elongation factor 3 (EF‐3) is an essential requirement for translation in fungi. We previously reported activation of EF‐3‐ATPase by yeast ribosomes. EF‐3 interacts with both ribosomal subunits and shows high affinity for 60S subparticles. Translational inhibitors α‐sarcin, ricin and auto‐immune antibodies to GTPase‐activation center inhibit binding of EF‐2 but not of EF‐3 to yeast ribosomes. EF‐2 competes with EF‐3 for the ribosomal binding sites and inhibits EF‐3‐ATPase activity. Neomycin relieves the inhibitory effect of EF‐2 on EF‐3 function. The apparent competition between EF‐2 and EF‐3 may represent binding of these two proteins to specific conformational states of the ribosome.EF‐3 stimulates ternary complex binding to yeast ribosomes. Neither the binding of EF‐3 to ribosomes, nor the ribosome‐dependent EF‐3‐ATPase activity are influenced by EF‐1α. Three lines of experimental evidence suggest a direct interaction between EF‐1α and EF‐3. A polyclonal antibody to EF‐3 immunoprecipitates EF‐1α along with EF‐3. EF‐1α co‐migrates with GST‐EF‐3 on glutathione‐Sepharose columns. ELISA tests demonstrate an interference of EF‐3/anti‐EF‐3 interaction by EF‐1α but not by EF‐2. These results strongly suggest that the stimulatory effect of EF‐3 on the ternary complex binding to yeast ribosomes involves a direct interaction between EF‐1α and EF‐3.
The strict molybdate‐dependence of glucose‐degradation by the thermoacidophile Sulfolobus acidocaldarius reveals the first crenarchaeotic molybdenum containing enzyme – an aldehyde oxidoreductase
Authors: Kardinahl Simone , Schmidt Christian L. , Hansen Thomas , Anemüller Stefan , Petersen Arnd , Schäfer Günter 
Published: March 2003

In order to investigate the effects of trace elements on different metabolic pathways, the thermoacidophilic Crenarchaeon Sulfolobus acidocaldarius (DSM 639) has been cultivated on various carbon substrates in the presence and absence of molybdate. When grown on glucose (but neither on glutamate nor casein hydrolysate) as sole carbon source, the lack of molybdate results in serious growth inhibition. By analysing cytosolic fractions of glucose adapted cells for molybdenum containing compounds, an aldehyde oxidoreductase was detected that is present in the cytosol to at least 0.4% of the soluble protein. With Cl2Ind (2,6‐dichlorophenolindophenol) as artificial electron acceptor, the enzyme exhibits oxidizing activity towards glyceraldehyde, glyceraldehyde‐3‐phosphate, isobutyraldehyde, formaldehyde, acetaldehyde and propionaldehyde. At its pH‐optimum (6.7), close to the intracellular pH of Sulfolobus, the glyceraldehyde‐oxidizing activity is predominant. The protein has an apparent molecular mass of 177 kDa and consists of three subunits of 80.5 kDa (α), 32 kDa (β) and 19.5 kDa (γ). It contains close to one Mo, four Fe, four acid‐labile sulphides and four phosphates per protein molecule. Methanol extraction revealed the existence of 1 FAD per molecule and 1 molybdopterin per molecule, which was identified as molybdopterin guanine dinucleotide on the basis of perchloric acid cleavage and thin layer chromatography. EPR‐spectra of the aerobically prepared enzyme exhibit the so‐called ‘desulpho‐inhibited’‐signal, known from chemically modified forms of molybdenum containing proteins. Anaerobically prepared samples show both, the signals arising from the active molybdenum‐cofactor as well as from the two [2Fe‐2S]‐clusters. According to metal‐, cofactor‐, and subunit‐composition, the enzyme resembles the members of the xanthine oxidase family. Nevertheless, the melting point and long‐term thermostability of the protein are outstanding and perfectly in tune with the growth temperature of S. acidocaldarius (80 °C).The findings suggest the enzyme to function as a glyceraldehyde oxidoreductase in the course of the nonphosphorylated Entner‐Doudoroff pathway and thereby may attribute a new physiological role to this class of enzyme.
The structural basis for the regulation of tissue transglutaminase by calcium ions
Authors: Casadio Rita , Polverini Eugenia , Mariani Paolo , Spinozzi Francesco , Carsughi Flavio , Fontana Angelo , de Laureto Patrizia Polverino , Matteucci Gabriella , Bergamini Carlo M. 
Published: March 2003

The role of calcium ions in the regulation of tissue transglutaminase is investigated by experimental approaches and computer modeling. A three‐dimensional model of the transglutaminase is computed by homology building on crystallized human factor XIII and is used to interpret structural and functional results. The molecule is a prolate ellipsoid (6.2 × 4.2 × 11 nm) and comprises four domains, assembled pairwise into N‐terminal and C‐terminal regions. The active site is hidden in a cleft between these regions and is inaccessible to macromolecular substrates in the calcium‐free form. Protein dynamics simulation indicates that these regions move apart upon addition of calcium ions, revealing the active site for catalysis. The protein dimensions are consistent with results obtained with small‐angle neutron and X‐ray scattering. The gyration radius of the protein (3 nm) increases in the presence of calcium ions (3.9 nm), but it is virtually unaffected in the presence of GTP, suggesting that only calcium ions can promote major structural changes in the native protein. Proteolysis of an exposed loop connecting the N‐terminal and C‐terminal regions is linearly correlated with enzyme inactivation and prevents the calcium‐induced conformational changes.