bluuebunny/crossref_metadata_2025_split huggingface dataset:
Does alcohol advertising promote adolescent drinking? Results from a longitudinal assessment
Authors: Ellickson Phyllis L. , Collins Rebecca L. , Hambarsoomians Katrin , McCaffrey Daniel F. 
Published: January 2005

ABSTRACTAims  To examine the relationship between exposure to different forms of alcohol advertising and subsequent drinking among US adolescents and assess whether exposure to an alcohol and drug prevention program mitigates any such relationship.Design  Regression models with multiple control variables examined the relationship between exposure to alcohol advertising in grade 8 and grade 9 drinking for two groups of South Dakotan adolescents: (1) seventh‐grade non‐drinkers (n = 1206) and (2) seventh‐grade drinkers (n = 1905). Interactions between the intervention program and the significant advertising predictors were tested.Setting  Forty‐one middle schools in South Dakota, USA.Participants  A total of 3111 seventh‐graders followed through grade 9.Measurements  Advertising variables were constructed for four types of alcohol advertising—television, in‐store displays, magazines and concession stands. Other predictors tested included measures tapping social influences, social bonds, problem behavior, alcohol beliefs, television exposure and demographics.Findings  For seventh‐grade non‐drinkers, exposure to in‐store beer displays predicted drinking onset by grade 9; for seventh‐grade drinkers, exposure to magazines with alcohol advertisements and to beer concession stands at sports or music events predicted frequency of grade 9 drinking. Although exposure to television beer advertising had a significant bivariate relationship with alcohol use for grade 7 non‐drinkers, it was not a significant predictor of drinking for either group in multivariate analyses. Participation in the prevention program, ALERT Plus, reduced future drinking for both groups and counteracted the effect of in‐store beer displays.Conclusions  Several forms of alcohol advertising predict adolescent drinking; which sources dominate depends on the child's prior experience with alcohol. Alcohol prevention programs and policies should help children counter alcohol advertising from multiple sources and limit exposure to these sources.
Laryngeal muscle fibre types
Authors: Hoh J. F. Y. 
Published: January 2005

SummaryThe internal laryngeal muscles have evolved to subserve the highly specialized functions of airways protection, respiration, and phonation. Their contractile properties, histochemistry, biochemical properties, myosin heavy chain (MyHC) expression and their regulation by nerves and hormones are reviewed and compared with limb muscle fibres. Cricothyroid, the vocal cord tensor, is limb‐like in MyHC composition and fibre type properties, while the vocal fold abductor and adductors are allotypically different, with capacity for expressing an isoform of MyHC that is kinetically faster than the fastest limb MyHC. In rats and rabbits the faster isoform is the extraocular (EO) MyHC, while in carnivores, it is the IIB MyHC. These adaptations enable the abductor and adductor muscles to remain always faster than the cricothyroid as the latter changes in speed during evolution to match changing metabolic and respiratory rates in relation to scaling with body mass. Such phylogenetic plasticity is vital to the airways protection and respiratory functions of these muscles. The posterior cricoarythenoid, the abductor muscle, is tonically driven during expiration, and consequently has a slower fibre type profile than the principal adductor, the thyroarythenoid. The human thyroarythenoid appears not to express EO or IIB MyHC significantly, but is unique in expressing the slow‐tonic MyHC. The concepts of allotype and phylogenetic plasticity help to explain differences in fibre type between limb and laryngeal muscles and between homologous laryngeal muscles in different species. Laryngeal muscle fibres exhibit physiological plasticity as do limb muscles, being subject to neural and hormonal modulation.
Leptin, cell proliferation and crypt fission in the gastrointestinal tract of intravenously fed rats
Authors: FitzGerald A. J. , Mandir N. , Goodlad R. A. 
Published: January 2005

Abstract.  Many peptides, hormones and growth factors have been implicated in the control of cell renewal in the gastrointestinal epithelium. Leptin is present in the stomach and salivary glands and leptin receptors are seen throughout the gut. Leptin can stimulate mitogen‐activated protein kinase activity in vitro and short‐term infusion has been reported to have a proliferative action on the colon in vivo, suggesting a biological link between obesity, physical activity and colon cancer. Food intake is one of the most important determinants of intestinal mucosal cell renewal, thus any direct effects of leptin on the gut may be hidden. This problem has been avoided experimentally by maintaining animals on total parenteral nutrition (TPN). Male Wistar rats were anaesthetized and cannulae were inserted into the jugular vein to deliver the TPN diet to which had been added 0, 0.5, 2.5, or 10 mg/kg of recombinant murine leptin. Orally fed rats were also studied. After 6 days of treatment, all animals were injected with vincristine and killed 2 h later. Tissue weight was recorded and crypt cell proliferation (arrested metaphases) and crypt fission were scored in ‘microdissected’ crypts. Leptin infusion led to a small decrease in body weight and in the weight of the caecum. Intestinal cell proliferation was significantly reduced by TPN when compared to the orally fed rats, but the addition of leptin had no effect on the small intestine or colon. Crypt fission was also significantly lowered in the TPN group. Fission was slightly but significantly increased in the proximal and mid‐colon of the leptin‐treated rats, but was decreased in the distal colon. Although leptin did not significantly alter cell proliferation, it had significant effects on the process of crypt fission in the colon, which varied according to the exact locality.
Effect of stem cell mobilization with cyclophosphamide plus granulocyte colony‐stimulating factor on morphology of haematopoietic organs in mice
Authors: Szumilas P. , Barcew K. , Baśkiewicz‐Masiuk M. , Wiszniewska B. , Ratajczak M. Z. , Machaliński B. 
Published: January 2005

Abstract.  Both granulocyte colony‐stimulating factor (G‐CSF) and cyclophosphamide (CY) are employed in the clinic as mobilizing agents to stimulate the egress of haematopoietic stem/progenitor cells (HSPC) from bone marrow (BM) into peripheral blood (PB). However, although both compounds are effective, the simultaneous administration of G‐CSF + CY allows for optimal mobilization. The aim of this study was to compare morphological changes in major haematopoietic organs in mice mobilized by G‐CSF + CY. We employed the standard G‐CSF + CY mobilization protocol, in which mice were injected at day 0 with a single dose of CY followed by daily injection of G‐CSF for 6 consecutive days. We noticed that the cytoreductive effect of CY on BM and spleen tissue was compensated at day 2 by the pro‐proliferative effect of G‐CSF. Furthermore, as evidenced by histological examination of BM sections at day 4, egress of haematopoietic cells from BM was accelerated by 2 days as compared to mobilization by G‐CSF or CY alone; also, by day 6 there was accumulation of early haematopoietic (Thy‐1low c‐kit+) cells in the spleens and livers of mobilized animals. This implies that HSPC that are mobilized from BM and circulate in PB may ‘home’ to peripheral organs. We envision that such an accumulation of these cells in the spleen (which is a major haematopoietic organ in mouse) allows them to participate in haematopoietic reconstitution. Their homing to other sites (for example the liver) is evidence that BM‐derived stem cells are playing a pivotal role in organ/tissue regeneration. The potential involvement of major chemoattractants for stem cells, like stromal‐derived factor‐1 which is induced by CY in various regenerating organs such as the liver, requires further study. We conclude that inclusion of CY into mobilization protocols on the one hand efficiently increases the egress of HSPC from the BM, but on the other hand may lead to the relocation of BM stem cell pools to peripheral tissues.
A constitutively active GPCR retains its G protein specificity and the ability to form dimers
Authors: Ladds Graham , Davis Kevin , Das Anamika , Davey John 
Published: January 2005

SummaryG protein‐coupled receptors (GPCRs) are cell surface proteins which help to regulate the physiology of all the major organ systems within higher eukaryotes. They are stimulated by multiple ligands and activate a range of effector molecules to bring about changes in cell behaviour. The use of constitutively active mutants (CAMs) of GPCRs has enabled a better understanding of receptor activation as CAMs exhibit ligand‐independent signalling negating the use of ligands. Here we introduce the fission yeast Schizosaccharomyces pombe as a host for producing CAMs, by describing the isolation and characterization of constitutive mutants of the P‐factor receptor (Mam2). One mutant Mam2[P261L] contained a single‐amino‐acid substitution (Pro261 to Leu) within a region of high homology in GPCRs. Substitution of this proline leads to an 18‐fold increase in ligand‐independent signalling. We utilized Mam2[P261L] to investigate CAM activity by demonstrating that Mam2[P261L] is efficiently trafficked to the cell surface where it can form fully functional oligomeric complexes with the native receptor. Mam2[P261L] also retains the G protein specificity (RG‐profile) of the native receptor and only induces constitutive signalling in the same G proteins. Finally, evidence is provided to indicate that CAM activity results from a reduction in the kinetics of G protein binding. This is the first time that S. pombe has been utilized for isolating and characterizing CAMs and the techniques employed will complement the current systems available for studying these important receptors.
Carbapenem antibiotic biosynthesis in Erwinia carotovora is regulated by physiological and genetic factors modulating the quorum sensing‐dependent control pathway
Authors: McGowan Simon J. , Barnard Anne M. L. , Bosgelmez Gulgun , Sebaihia Mohammed , Simpson Natalie J. L. , Thomson Nicholas R. , Todd Daniel E. , Welch Martin , Whitehead Neil A. , Salmond George P. C. 
Published: January 2005

Summary Erwinia carotovora produces the β‐lactam antibiotic, carbapenem, in response to a quorum sensing signalling molecule, N‐(3‐oxohexanoyl)‐ l‐homoserine lactone (OHHL). We have mapped the OHHL‐dependent promoter upstream of the first of the biosynthetic genes, carA. We have also analysed the effect on this promoter of the known genetic regulators of carbapenem expression, carR, carI (encoding homologues of LuxR and LuxI respectively) and hor (encoding a SlyA/MarR‐like transcriptional regulator). We describe a previously unknown promoter located within the carA‐H operon. This promoter does not respond to CarR and is required for quorum sensing‐independent expression of the carbapenem resistance determinants encoded by the carFG genes. We have mapped the carR, carI and hor transcription start points, shown that CarR is positively autoregulated in the presence of OHHL, and have demonstrated negative feedback affecting transcription of carI. In addition, various environmental  and physiological factors were shown to impinge on the transcription of the car biosynthetic genes. The nature of the carbon source and the temperature of growth influence carbapenem production by modulating the level of the OHHL signalling molecule, and thereby physiologically fine‐tune the quorum sensing regulatory system.
Recoding in Archaea
Authors: Cobucci‐Ponzano Beatrice , Rossi Mosè , Moracci Marco 
Published: January 2005

SummaryStandard decoding of the genetic information into polypeptides is performed by one of the most sophisticated cell machineries, the translating ribosome, which, by following the genetic code, ensures the correspondence between the mature mRNA and the protein sequence. However, the expression of a minority of genes requires programmed deviations from the standard decoding rules, globally named recoding. This includes ribosome programmed –/+1 frameshifting, ribosome hopping, and stop codon readthrough. Recoding in Archaea was unequivocally demonstrated only for the translation of the UGA stop codon into the amino acid selenocysteine. However, a new recoding event leading to the 22nd amino acid pyrrolysine and the preliminary reports on a gene regulated by programmed −1 frameshifting have been recently described in Archaea. Therefore, it appears that the study of this phenomenon in Archaea is still at its dawn and that most of the genes whose expression is regulated by recoding are still uncharacterized.
The polo‐like kinase PLKA is required for initiation and progression through mitosis in the filamentous fungus Aspergillus nidulans
Authors: Bachewich Catherine , Masker Kathryn , Osmani Stephen 
Published: January 2005

SummaryPolo‐like kinases (PLK) function during multiple stages of mitotic progression and in cytokinesis. We identified and cloned a PLK homologue in Aspergillus nidulans, plkA, which is the first PLK reported in a filamentous fungus and the largest member of the PLK family to date. As plkA was essential, the effects of overexpression and localization of protein in living cells were explored to determine PLKA function. Overexpression of PLKA permitted hyphal formation, but blocked nuclear division in interphase. In NIMA or NIMT temperature‐sensitive backgrounds, overexpression of PLKA impaired normal entry into mitosis upon release from restrictive temperature, supporting a role for PLKA during G2/M. In the few mitotic cells present, spindles were monopolar or disorganized, and chromatin condensation and segregation were impaired, suggesting additional roles for PLKA in spindle formation and in chromosome dynamics. Consistent with this, green fluorescent protein (GFP)‐tagged PLKA could localize to the spb during interphase, and to the spb and nucleus throughout mitosis. Intriguingly, PLKA remained on the spb during telophase and into G1, in contrast to other PLK. In addition, spb localization was independent of NIMA function, unlike that demonstrated in Schizosaccharomyces pombe where PLK localization to the spb required the NIMA homologue Fin1. PLKA was not detected at cortical, septation‐associated sites, and overexpression did not drive septum formation, also in contrast to that observed with other PLK. Therefore, PLKA is important for multiple events during mitosis, similar to PLK in higher organisms, but exhibits differences in size, localization and influence on septation/cytokinesis, suggesting additional novel regulatory features.
In vitro reconstitution of a trimeric complex of DivIB, DivIC and FtsL, and their transient co‐localization at the division site in Streptococcus pneumoniae
Authors: Noirclerc‐Savoye Marjolaine , Le Gouëllec Audrey , Morlot Cécile , Dideberg Otto , Vernet Thierry , Zapun André 
Published: January 2005

SummaryDivIB, DivIC and FtsL are bacterial proteins essential for cell division, which show interdependencies for their stabilities and localization. We have reconstituted in vitro a trimeric complex consisting of the recombinant extracellular domains of the three proteins from Streptococcus pneumoniae. The extracellular domain of DivIB was found to associate with a heterodimer of those of DivIC and FtsL. The heterodimerization of DivIC and FtsL was artificially constrained by fusion with interacting coiled‐coils. Immunofluorescence experiments showed that DivIC is always localized at mid‐cell, in contrast to DivIB and FtsL, which are co‐localized with DivIC only during septation. Taken together, our data suggest that assembly of the trimeric complex DivIB/DivIC/FtsL is regulated during the cell cycle through controlled formation of the DivIC/FtsL heterodimer.
The expression of a novel antisense gene mediates incompatibility within the large repABC family of α‐proteobacterial plasmids
Authors: MacLellan Shawn R. , Smallbone Laura A. , Sibley Christopher D. , Finan Turlough M. 
Published: January 2005

SummaryLarge extrachromosomal replicons in many members of the α‐proteobacteria encode genes that are required for plant or animal pathogenesis or symbiosis. Most of these replicons encode repABC genes that control their replication and faithful segregation during cell division. In addition to its chromosome, the plant endosymbiont Sinorhizobium meliloti also maintains the 1.4 Mb pSymA and 1.7 Mb pSymB symbiotic megaplasmids both of which are repABC‐type replicons. In all repABC loci that have been characterized, an apparently untranslated intergenic region between the repB and repC genes encodes a strong incompatibility determinant (referred to as incα). Here we report the isolation of mutations within the incα regions of pSymA and pSymB that eliminate incompatibility. These mutations map to and inactivate a promoter in the intergenic region that drives the expression of an approximately 56 nucleotide untranslated RNA molecule that mediates incompatibility. This gene, that we have named incA, is transcribed antisense to the repABC genes. Our analysis suggests that the incA gene is conserved in repABC loci from a diverse spectrum of bacteria.
GlcP constitutes the major glucose uptake system of Streptomyces coelicolor A3(2)
Authors: Van Wezel Gilles P. , Mahr Kerstin , König Miriam , Traag Bjørn A. , Pimentel‐Schmitt Elisângela F. , Willimek Andreas , Titgemeyer Fritz 
Published: January 2005

SummaryWe provide a functional and regulatory analysis of glcP, encoding the major glucose transporter of Streptomyces coelicolor A3(2). GlcP, a member of the Major Facilitator Superfamily (MFS) of bacterial and eucaryotic sugar permeases, was found to be encoded twice at two distinct loci, glcP1 and glcP2, located in the central core and in the variable right arm of the chromosome respectively. Heterologous expression of GlcP in Escherichia coli led to the full restoration of glucose fermentation to mutants lacking glucose transport activity. Biochemical analysis revealed an affinity constant in the low‐micromolar range and substrate specificity for glucose and 2‐deoxyglucose. Deletion of glcP1 but not glcP2 led to a drastic reduction in growth on glucose reflected by the loss of glucose uptake. This correlated with transcriptional analyses, which showed that glcP1 transcription was strongly inducible by glucose, while glcP2 transcripts were barely detectable. In conclusion, GlcP, which is the first glucose permease from high G+C Gram‐positive bacteria characterized at the molecular level, represents the major glucose uptake system in S. coelicolor A3(2) that is indispensable for the high growth rate on glucose. It is anticipated that the activity of GlcP is linked to other glucose‐mediated phenomena such as carbon catabolite repression, morphogenesis and antibiotic production.
Receptor binding studies disclose a novel class of high‐affinity inhibitors of the Escherichia coli FimH adhesin
Authors: Bouckaert Julie , Berglund Jenny , Schembri Mark , De Genst Erwin , Cools Lieve , Wuhrer Manfred , Hung Chia‐Suei , Pinkner Jerome , Slättegård Rikard , Zavialov Anton , Choudhury Devapriya , Langermann Solomon , Hultgren Scott J. , Wyns Lode , Klemm Per , Oscarson Stefan , Knight Stefan D. , De Greve Henri 
Published: January 2005

SummaryMannose‐binding type 1 pili are important virulence factors for the establishment of Escherichia coli urinary tract infections (UTIs). These infections are initiated by adhesion of uropathogenic E. coli to uroplakin receptors in the uroepithelium via the FimH adhesin located at the tips of type 1 pili. Blocking of bacterial adhesion is able to prevent infection. Here, we provide for the first time binding data of the molecular events underlying type 1 fimbrial adherence, by crystallographic analyses of the FimH receptor binding domains from a uropathogenic and a K‐12 strain, and affinity measurements with mannose, common mono‐ and disaccharides, and a series of alkyl and aryl mannosides. Our results illustrate that the lectin domain of the FimH adhesin is a stable and functional entity and that an exogenous butyl α‐ d‐mannoside, bound in  the  crystal  structures,  exhibits  a  significantly better affinity for FimH (Kd = 0.15 µM) than mannose (Kd = 2.3 µM). Exploration of the binding affinities of α‐ d‐mannosides with longer alkyl tails revealed affinities up to 5 nM. Aryl mannosides and fructose can also bind with high affinities to the FimH lectin domain, with a 100‐fold improvement and 15‐fold reduction in affinity, respectively, compared with mannose. Taken together, these relative FimH affinities correlate exceptionally well with the relative concentrations of the same glycans needed for the inhibition of adherence of type 1 piliated E. coli. We foresee that our findings will spark new ideas and initiatives for the development of UTI vaccines and anti‐adhesive drugs to prevent anticipated and recurrent UTIs.
From fundamental studies of sporulation to applied spore research
Authors: Barák Imrich , Ricca Ezio , Cutting Simon M. 
Published: January 2005

SummarySporulation in the Gram‐positive bacterium, Bacillus subtilis, has been used as an excellent model system to study cell differentiation for almost half a century. This research has given us a detailed picture of the genetic, physiological and biochemical mechanisms that allow bacteria to survive harsh environmental conditions by forming highly robust spores. Although many basic aspects of this process are now understood in great detail, including the crystal and NMR structures of some of the key proteins and their complexes, bacterial sporulation still continues to be a highly attractive model for studying various cell processes at a molecular level. There are several reasons for such scientific interest. First, some of the complex steps in sporulation are not fully understood and/or are only described by ‘controversial’ models. Second, intensive research on unicellular development of a single microorganism, B. subtilis, left us largely unaware of the multitude of diverse sporulation mechanisms in many other Gram‐positive endospore and exospore formers. This diversity would likely be increased if we were to include sporulation processes in the Gram‐negative spore formers. Spore formers have great potential in applied research. They have been used for many years as biodosimeters and as natural insecticides, exploited in the industrial production of enzymes, antibiotics, used as probiotics and, more, exploited as possible vectors for drug delivery, vaccine antigens and other immunomodulating molecules. This report describes these and other aspects of current fundamental and applied spore research that were presented at European Spores Conference held in Smolenice Castle, Slovakia, June 2004.