bluuebunny/crossref_metadata_2025_split huggingface dataset:
Holo‐BtuF stabilizes the open conformation of the vitamin B12 ABC transporter BtuCD
Authors: Kandt Christian , Tieleman D. Peter 
Published: September 2009

AbstractWhile there is evidence that other ABC transporters can tell between empty and loaded substrate binding protein, reconstitution experiments suggest otherwise for the Escherichia coli vitamin B12 importer BtuCD‐F. Here, we address the question of BtuCD‐F substrate sensitivity in a combined protein–protein docking and molecular dynamics simulation approach. Starting from the BtuCD and holo‐BtuF crystal structures, we model two holo‐BtuCD‐F docking complexes differing by a 180° orientation of BtuF. One of these is similar to the apo‐BtuCD‐F crystal structure. Both docking complexes were embedded in a lipid/water environment to investigate their dynamics and BtuCD's conformational response to the presence and absence of BtuF, vitamin B12, and Mg‐ATP in a series of 28 independent MD simulations. We find holo‐BtuF stabilizing the open conformation of BtuCD, whereas the transporter begins to close again when BtuF or vitamin B12 is removed—suggesting BtuCD‐F is capable of substrate sensitivity. We identified BtuC transmembrane helices 3 and 5, the L‐loops and the adjacent helices comprised of BtuC residues 170–180 as hotspots of conformational change. We propose the latter to act as substrate sensors. BtuF‐Trp44 appears to act as a lid on the vitamin B12 binding cleft in BtuF X‐ray structures and protrudes into the BtuCD transport channel in one of our simulations, which might represent an initial step in vitamin B12 uptake. On an average, we observe subunit motions where the nucleotide binding domains approach each other while the transmembrane domains display an opening trend toward the periplasm. Proteins 2010. © 2009 Wiley‐Liss, Inc.
Internet security meets the IP multimedia subsystem: an overview
Authors: Berger Andreas , Gojmerac Ivan , Jung Oliver 
Published: September 2009

AbstractIn this paper, we discuss the security threats of next‐generation telecommunication core networks induced by the adoption of Internet technology. The 3GPP IP multimedia subsystem (IMS) is based on the Internet protocol (IP) and hence inherits many security problems from the Internet world. We provide a review of the most prominent vulnerabilities, covering both fundamental functions like routing and name resolution as well as message tampering and implementation attacks, and we show their impact on the IMS. Further, we address the topics of denial of service (DoS) attacks and unsolicited communication (UC). Despite the large number of security threats, the IMS standardization foresees no security monitoring and fully relies on standard countermeasures as known from the Internet. This paper provides a survey of these threats and relates them to the available solutions. We motivate the need for a powerful and modular monitoring platform for the IMS and provide an overview of the existing work in this research field. Copyright © 2009 John Wiley & Sons, Ltd.
The use of an interim CEO during succession episodes and firm performance
Authors: Ballinger Gary A. , Marcel Jeremy J. 
Published: September 2009

AbstractOur study investigates an unexplored succession process—interim CEO successions. We define an interim CEO succession as a case where the title of chief executive officer is vacated by the incumbent and the board of directors has not announced a permanent successor, but instead designates a particular individual as ‘interim CEO,’ or ‘acting CEO,’ or ‘CEO until a permanent successor is named.’ Theory predicts that interim CEO successions will lead to the type of disruption that can harm firm performance, even after a permanent successor is appointed. Our data show that interim CEO succession processes are widely employed by publicly‐traded U.S. firms, and that they are associated with lower performance during the period in which the interim serves. However, whether the interim CEO also simultaneously serves as chairman moderates the impact of this type of succession on firm performance, as well as on long‐term firm survival. Copyright © 2009 John Wiley & Sons, Ltd.
The routine may be stable but the advantage is not: competitive implications of key employee mobility
Authors: Aime Federico , Johnson Scott , Ridge Jason W. , Hill Aaron D. 
Published: September 2009

AbstractWe extend our theoretical understanding of the effect of key employee mobility on organizational performance. We find that when an organization with an advantageous set of routines loses a key employee to a competitor, the advantaged organization's competitive position is reduced vis‐à‐vis the hiring competitor. What is more interesting is that we also show that the diffusion of an advantageous set of routines through the mobility of key employees may affect competitive advantage in at least two additional ways. Our findings result from an analysis of 412 competitive events between the San Francisco 49ers and all other teams in the National Football League during the 24‐year period when the San Francisco 49ers perfected the routines of a strategic innovation that has become known as the West Coast Offense. First, we find that there is a loss of advantage for the organization when competitors increasingly compete against additional organizations that hired key employees from it. Second, we find that there is a loss of advantage for the organization when competitors expect future competition against additional organizations that hired key employees from it. Our results challenge the traditional argument that socially complex routines create sustainable competitive advantages because they are not easily imitated and do not rely on any single individual. Instead, we show that routines are stable to the loss of key employees, but the advantages derived from them are not. Copyright © 2009 John Wiley & Sons, Ltd.
Direct Imaging of Immune Rejection and Memory Induction by Allogeneic Mesenchymal Stromal Cells
Authors: Zangi Lior , Margalit Raanan , Reich-Zeliger Shlomit , Bachar-Lustig Esther , Beilhack Andreas , Negrin Robert , Reisner Yair 
Published: September 2009

Abstract
Although mesenchymal stromal cells (MSCs) exhibit marked immunoregulatory activity through multiple mechanisms, their potential to completely evade rejection upon transplantation into allogeneic recipients is controversial. To directly address this controversy, the survival of luciferase-labeled MSCs (Luc+ MSCs) was evaluated by imaging in allogeneic recipients. This analysis showed that although MSCs exhibited longer survival compared to fibroblasts (Fib), their survival was significantly shorter compared to that exhibited in syngeneic or in immune-deficient Balb-Nude or non-obese diabetic severe combined immunodeficiency (NOD-SCID) recipients. Graft rejection in re-challenge experiments infusing Luc+ Fib into mice, which had previously rejected Luc+ MSCs, indicated potential induction of immune memory by the MSCs. This was further analyzed in T-cell antigen receptor (TCR) transgeneic mice in which either CD4 TEA mice or CD8 T cells (2C mice) bear a TCR transgene against a specific MHC I or MHC II, respectively. Thus, following a re-challenge with MSCs expressing the cognate MHC haplotype, an enhanced percentage of 2C CD8+ or TEA CD4+ T cells exhibited a memory phenotype (CD122+, CD44+, and CD62Llow). Collectively, these results demonstrate that MSCs are not intrinsically immune-privileged, and under allogeneic settings, these cells induce rejection, which is followed by an immune memory. Considering that the use of allogeneic or even a third party (“off the shelf”) MSCs is commonly advocated for a variety of clinical applications, our results strongly suggest that long-term survival of allogeneic MSCs likely represents a major challenge.
Disclosure of potential conflicts of interest is found at the end of this article.
Yeast Ste23p shares functional similarities with mammalian insulin‐degrading enzymes
Authors: Alper Benjamin J. , Rowse Jarrad W. , Schmidt Walter K. 
Published: September 2009

AbstractThe S. cerevisiae genome encodes two M16A enzymes: Axl1p and Ste23p. Of the two, Ste23p shares significantly higher sequence identity with M16A enzymes from other species, including mammalian insulin‐degrading enzymes (IDEs). In this study, recombinant Ste23p and R. norvegicus IDE (RnIDE) were isolated from E. coli, and their enzymatic properties compared. Ste23p was found to cleave established RnIDE substrates, including the amyloid‐β peptide (Aβ1–40) and insulin B‐chain. A novel internally quenched fluorogenic substrate (Abz–SEKKDNYIIKGV–nitroY‐OH) based on the polypeptide sequence of the yeast P2 a‐factor mating propheromone was determined to be a suitable substrate for both Ste23p and RnIDE, and was used to conduct comparative enzymological studies. Both enzymes were most active at 37 °C, in alkaline buffers and in high salt environments. In addition, the proteolytic activities of both enzymes towards the fluorogenic substrate were inhibited by metal chelators, thiol modifiers, inhibitors of cysteine protease activity and insulin. Characteristics of STE23 expression were also evaluated. Our analysis indicates that the 5′ terminus of the STE23 gene has been mischaracterized, with the physiologically relevant initiator corresponding to residue M53 of the publicly annotated protein sequence. Finally, we demonstrate that, unlike haploid‐specific Axl1p, Ste23p is expressed in both haploid and diploid cell types. Our study presents the first comprehensive biochemical analysis of a yeast M16A enzyme, and provides evidence that S. cerevisiae Ste23p has enzymatic properties that are highly consistent with mammalian IDEs and other M16A enzymes. Copyright © 2009 John Wiley & Sons, Ltd.
Zinc‐finger intron 7: a new locus for sex identification of giant panda (Ailuropoda melanoleuca)
Authors: Xu Xiao , Li Yuzhi , Wang Xiaofang , Wei Kun , Zhang Wenping , Zhang Zhihe , Shen Fujun , Yue Bisong 
Published: September 2009

AbstractWe developed a single‐reaction test for identifying the sex of giant panda (Ailuropoda melanoleuca) targeted to co‐amplify homologous fragments with size polymorphism that located at zinc‐finger (ZF) intron 7 by using one pair of primers. This assay produced one sex‐specific fragment in females (XX genotypes) whereas two fragments were produced in males (XY genotypes). Indels (insertion/deletion) in intron 7 of Y‐linked allele provide a significant discrimination between ZFX and ZFY, thus the amplification products can be simply distinguished by agarose gel electrophoresis, exhibiting sex‐specific banding patterns (female, 354 bp; male, 354 bp, 135 bp). The new primer set was successfully tested on known‐sex giant pandas by using template DNA extracted from both blood and fecal samples. Cross‐species test was also performed, revealing that this assay could be applied to other Ursidae species. Zoo Biol 29:526–531, 2010. © 2009 Wiley‐Liss, Inc.
To pay or not to pay? Monitoring performance and enforcing conditionality when paying for forest conservation in Mexico
Authors: HONEY-ROSÉS JORDI , LÓPEZ-GARCÍA JOSÉ , RENDÓN-SALINAS EDUARDO , PERALTA-HIGUERA ARMANDO , GALINDO-LEAL CARLOS 
Published: September 2009

SUMMARYPaying landowners to conserve forests is a promising new strategy to protect biodiversity and ecosystem services. However to succeed with this approach, programme managers need reliable monitoring data to make informed payment decisions. This includes withholding payment from landowners who do not meet conservation objectives. The monitoring method used for the Monarch Butterfly Conservation Fund compared aerial photographs and conducted field sampling to identify forest changes. The comparison of aerial photographs showed that 161 hectares of forest were degraded in the central core zone of the Monarch Butterfly Biosphere Reserve in Mexico between 2001 and 2003. As a result, payment was withheld from one of 13 landowners. Analysis of high resolution (0.6 m) digital aerial photographs did not detect finer scale changes, despite obtaining an average pixel resolution 1000 times greater than Landsat satellite imagery. This suggests that current payment for ecosystem services programmes are underestimating environmental change and overpaying non-compliant participants. In addition, selecting a decision rule to enforce payment conditionality raised new questions about how much ecosystem degradation should be permitted before withholding payment. Sound decisions about withholding payment cannot be developed until the marginal value of ecosystem services is better understood. Until then, payment thresholds can be based on specific policy objectives.
Dietary patterns associated with metabolic syndrome, sociodemographic and lifestyle factors in young adults: the Bogalusa Heart Study
Authors: Deshmukh-Taskar Priya R , O’Neil Carol E , Nicklas Theresa A , Yang Su-Jau , Liu Yan , Gustat Jeanette , Berenson Gerald S 
Published: September 2009

AbstractObjectiveTo examine the association between dietary patterns (DP) and risk for metabolic syndrome (MetS); and to identify differences in DP by socio-economic, demographic and lifestyle factors.DesignDietary intake (from an FFQ), anthropometric/biochemical parameters and sociodemographic/lifestyle information (from a self-reported questionnaire) were evaluated, using a cross-sectional design. Statistical methods included principal component factor analysis, analysis of covariance and linear regression. All analyses were covariate-adjusted.SettingThe Bogalusa Heart Study (1995–1996), USA.SubjectsYoung adults (19–39 years; n 995; 61 % females/39 % males; 80 % whites/20 % blacks) from a semi-rural southern US community were examined.ResultsThe ‘Western Dietary Pattern’ (WDP) consisted of refined grains, French fries, high-fat dairy foods, cheese dishes, red meats, processed meats, eggs, snacks, sweets/desserts, sweetened beverages and condiments. The ‘Prudent Dietary Pattern’ (PDP) consisted of whole grains, legumes, vegetables, fruits, 100 % fruit juices, low-fat dairy products, poultry, clear soups and low-fat salad dressings. The DP explained 31 % of the dietary intake variance. Waist circumference (P = 0·02), triceps skinfold (P = 0·01), plasma insulin (P = 0·03), serum TAG (P = 0·05), and the occurrence of MetS (P = 0·03) were all inversely associated with PDP. Insulin sensitivity (P < 0·0005) was positively associated with PDP. Serum HDL cholesterol (P = 0·05) was inversely associated with WDP. Blacks consumed more servings from WDP than whites (P = 0·02). Females consumed more servings from PDP than males (P = 0·002). Those with >12 years of education consumed more servings from PDP than their counterparts (P < 0·0001). Current smokers consumed more servings from WDP than current non-smokers (P < 0·0001). Physically very active young adults consumed fewer servings from WDP than their sedentary counterparts (P = 0·02).ConclusionsMore studies are warranted to confirm these findings in other populations.
Histomorphometric characteristics and expression of epidermal growth factor and its receptor by epithelial cells of normal gingiva and hereditary gingival fibromatosis
Authors: Araujo C. S. A. , Graner E. , Almeida O. P. , Sauk J. J. , Coletta R. D. 
Published: September 2009

Objective:  The objective of this study was to examine the histomorphometric features and evaluate the expression of epidermal growth factor (EGF) and transmembranic receptor (EGFr) and the proliferative potential of epithelial cells from normal and hereditary gingival fibromatosis (HGF) gingival tissues.Background:  EGF is a multifunctional cytokine with a variety of biological effects including stimulation of cell proliferation by binding to its specific EGFr.Methods:  Immunohistochemistry was performed to measure EGF and EGFr expression and the epithelial cell proliferation was determined by measuring proliferating cell nuclear antigen (PCNA).Results:  Histomorphometric evaluation indicated that in HGF the mean height of the epithelial papillae was higher compared to the normal gingiva (NG), whereas mean epithelial area and number of epithelial papillae were quite similar in both groups. The EGF and EGFr positive cells were observed in the basal, spinous and granular cell layers of both normal and HGF tissues, with a gradual reduction from the basal layer. Although the expressions of EGF and EGFr in the control group were significantly higher than those from HGF, in HGF the epithelial papilla tips showed increased number of proliferating cells and elevated expression of EGF and EGFr. There was a correlation between the proliferative potential of epithelial cells and the expression of EGF or EGFr only in the epithelial papilla tips of HGF gingiva.Conclusion:  Our data suggest that EGF and EGFr in the oral epithelium of HGF gingiva may stimulate epithelial cell proliferation, with the resultant apical migration of the oral epithelium and formation of the slender deep epithelial papillae; however, without hyperplastic alterations.
Granulocyte elastase activity in static and flow gingival crevicular fluid
Authors: Jin Lijian , Yu Chun , Corbet Esmonde F. 
Published: September 2009

Objectives:  This study aimed to evaluate the volume of gingival crevicular fluid (GCF) and granulocyte elastase activity in static GCF (sGCF) and flow GCF (fGCF) from subjects with various periodontal conditions.Methods:  Eleven periodontally healthy, 10 gingivitis and 12 periodontitis subjects were recruited and the sites investigated consisted of healthy sites from healthy subjects (HH); healthy (HG) and gingivitis sites (GG) from gingivitis subjects; and healthy (HP), gingivitis (GP) and periodontitis sites (PP) from periodontitis subjects. fGCF samples were collected either 1 min or 5 min following sGCF collection by paper strip technique. GCF volume was determined by Periotron® 6000 and granulocyte elastase activity was assayed with a specific substrate [l‐pyroglutamyl‐l‐prolyl‐l‐valine‐p‐nitroanilide(pGluProVal‐pNA)].Results:  At baseline, no significant differences existed in clinical and GCF parameters between the two matched sites for subsequent collection of fGCF samples either 1 min or 5 min after sGCF sampling in all subjects. The flow exudate in HG and HP sites quickly replenished to sGCF levels, while a delayed replenishment was found in HH sites, despite the similar sGCF volumes of these sites. The GCF volume and elastase levels in the fGCF at 1 min were higher in GP sites than in GG sites (P < 0.05). Overall, depletion of elastase levels in the fGCF at 1 min was observed in all subjects, whereas elastase levels in the fGCF at 5 min had replenished to sGCF levels in HP, GP, PP sites and GG sites, but had remained at a lower level in HH and HG sites. An overall positive correlation was found between sGCF and fGCF for GCF volume and elastase activity (P < 0.001); however, this correlation varied with GCF parameters and with site conditions of the subjects concerned.Conclusions:  This study shows that patterns of dynamic changes in GCF flow and elastase activity varied under different periodontal conditions. Assessment of both sGCF and fGCF may allow better insight into the dynamic change of the target components in GCF.
Expression of endothelins and their receptors in cells from human periodontal tissues
Authors: Fujioka Daisuke , Nakamura Shigeo , Yoshino Hiroshi , Shinohara Hiroaki , Shiba Hideki , Mizuno Noriyoshi , Hasegawa Naohiko , Shindoh Norihisa , Uchida Yuushi , Ogawa Tetsuji , Kawaguchi Hiroyuki , Kurihara Hidemi 
Published: September 2009

Objective: The present study investigated the presence of ET‐1 in gingival crevicular fluid (GCF) from patients with periodontitis, and the expression of endothelins (ETs) and their receptors mRNA in cultured cells from human periodontal tissues.Background: ET was originally discovered as a potent vasoconstrictive peptide from endothelial cells. It has been reported that ETs are produced by various cells besides endothelial cells. ETs are related to inflammatory and sclerotic lesions, such as arteriolosclerosis and hepatic cirrhosis. Therefore, ETs may be involved in periodontal disease. However, the roles of ETs in development and progression of periodontal disease are not clear.Methods: ET‐1 released from the cultured cells was measured by enzyme‐linked immunosorbent assay. mRNA expressions for ETs and their receptors were examined by reverse transcription‐polymerase chain reaction and Northern blotting analysis.Results: ET‐1 levels in GCF from patients with periodontitis were higher than those from healthy subjects. Human gingival keratinocytes (HGK) expressed mRNA for ETs and their receptors, ET‐Ar and ET‐Br. ET‐1 mRNA expression and ET‐1 peptide production from HGK were enhanced by interleukin‐1β and tumor necrosis factor‐α.Conclusions: These results suggest that ET‐1 plays a significant role in periodontal disease.
Serum antibody reactivity against recombinant PrtC of Porphyromonas gingivalis following periodontal therapy
Authors: Beikler T. , Ehmke B. , Wittstock M. , Schmidt H. , Karch H. , Flemmig T. F. 
Published: September 2009

Objectives:  In 34 patients with chronic periodontitis, the presence of IgA, IgG, and IgG subclass serum antibodies against recombinant PrtC (rPrtC) of Porphyromonas gingivalis was assessed by immunoblot analysis 24 months after therapy.Methods:  rPrtC was produced from P. gingivalis ATTC 33277 using the plasmid pGEX‐2T. In addition, intraoral colonization with P. gingivalis was detected by PCR in subgingival plaque and swab samples from buccal mucosae, tonsils and tongue at baseline, 10 d, and 3, 6, 9, 12, 18, and 24 months.Results:  All patients were found to harbor P. gingivalis in the oral cavity at least once during the observation period. The identified antibody responses against the rPrtC of P. gingivalis were IgA (97%, i.e. 33/34 patients) and IgG (100%, i.e. 34/34), with an IgG subclass distribution of IgG2 (65%, i.e. 22/34 patients) > IgG3 (47%, i.e. 16/34) > IgG1 (38%, i.e. 13/34) > IgG4 (29%, i.e. 10/34). Anti‐rPrtC IgA and IgG antibody reactivity was found in all but one patients (anti‐rPrtC IgA negative), who tested negative for P. gingivalis at all of the assessed intraoral sites for at least 6 months before sera collection. There was no association between IgG subclass reactivity against the rPrtC of P. gingivalis and progression of periodontal attachment loss.Conclusion:  The results indicated that anti‐rPrtC IgA and IgG antibodies may serve as an indicator for past or present intraoral colonization with P. gingivalis.