bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Arabidopsis MAP kinase kinase MKK1 participates in defence responses to the bacterial elicitor flagellin
Authors: Mészáros Tamás , Helfer Anne , Hatzimasoura Elizabeth , Magyar Zoltán , Serazetdinova Liliya , Rios Gabino , Bardóczy Viola , Teige Markus , Koncz Csaba , Peck Scott , Bögre László 
Published: October 2006

SummaryPlants sense pathogens through both pathogen‐associated molecular patterns and recognition of race‐specific virulence factors, which induce basal defence or an accelerated defence (often manifest in the form of local cell death), respectively. A mitogen‐activated protein kinase (MAPK) module in Arabidopsis was previously proposed to signal from perception of the bacterial elicitor flagellin to the activation of basal defence‐related genes. Here, we present evidence for a parallel MAPK‐signalling pathway involved in the response to flg22, a peptide corresponding to the most conserved domain of flagellin. The endogenous Arabidopsis MAP kinase kinase MKK1 is activated in cells treated with flg22, phosphorylates the MAPK MPK4 in vitro, and activates it in vivo in protoplasts. In mkk1 mutant plants, the activation by flg22 of MPK4 and two other flg22‐induced MAPKs (MPK3 and MPK6) is impaired. In the mkk1 mutant, a battery of both flg22‐induced and flg22‐repressed genes show altered expression, indicating that MKK1 negatively regulates the activity of flagellin‐responsive genes. Intriguingly, in contrast to the mpk4 mutant, mkk1 shows no morphological anomalies and is compromised in resistance to both virulent and avirulent Pseudomonas syringae strains. Thus, the MKK1 signalling pathway modulates the expression of genes responding to elicitors and plays an important role in pathogen defence.
Haematological and biochemical indices in young African children: in search of reference intervals
Authors: Quintó Llorenç , Aponte John J. , Sacarlal Jahit , Espasa Mateu , Aide Pedro , Mandomando Inacio , Guinovart Caterina , Macete Eusebio , Navia Margarita M. , Thompson Ricardo , Menéndez Clara , Alonso Pedro L. 
Published: October 2006

SummaryIntroduction  The reference intervals of haematological and biochemical indices currently used in Africa are derived from data collected from populations living in industrialized countries. Few studies have been performed in Africa questioning the validity of these values when applied to local African populations.Objective  To provide reference intervals of haematological [haemoglobin (Hb), white blood cells (WBC), haematocrit (Htc) and platelets] and biochemical indices (ALT, creatinine and bilirubin) for children aged 1–4 from a rural area of southern Mozambique.Methods  Reference intervals were developed using the 2.5 and 97.5 centiles. Partition tests were performed to evaluate age and gender differences. Quantile regression models were estimated for those variables in which age partition was recommended. Deviances from linearity in the estimated models were evaluated using fractional polynomials of first or second degree. Agreement to classify normality, using the estimated reference intervals or values in use in a western paediatric hospital, was made using the kappa statistic.Results  Reference intervals for Hb, WBC, Htc, platelets, ALT and creatinine show significant differences by age. Gender differences were observed for creatinine values, while for bilirubin there were no significant differences for age or gender. Estimated Hb and Htc reference intervals in African children were lower than the accepted western ones, while ALT values were higher in the former. Agreement between normal classification, using the estimated intervals or the western values, was from slight to fair.Conclusions  Reference intervals of haematological and biochemical indices based on results from western individuals of the same age are not in agreement with the estimated values for African children. These observed values should not be used as a rule to define normality, but are the ones usually found in this population where anaemia, malaria and high mortality rates are also common.
Species Recognition Influences Female Mate Preferences in the Common European Grasshopper (Chorthippus biguttulus Linnaeus, 1758)
Authors: Safi Kamran , Heinzle Jakob , Reinhold Klaus 
Published: October 2006

AbstractSpecies recognition and intraspecific mating preferences constitute two basic aspects of animal communication. Both can be considered as variations in response to signals and it has been suggested that they represent a continuum. Selection on species recognition could therefore influence intraspecific mating preferences. We show that females of the common European grasshopper Chorthippus biguttulus prefer conspecific male signals that can be distinguished more reliably from sympatrically occurring heterospecific signals. This suggests that in C. biguttulus, sexual selection might be influenced by pleiotropic effects from species recognition. The results show how the heterospecific signal environment could have determined why and in which direction specific traits become sexually selected.
Facing the challenges of e‐learning initiatives in African universities
Authors: Gunga Samson O. , Ricketts Ian W. 
Published: October 2006

AbstractThis paper explores the possibility of bringing e‐learning to African universities through collaborative networks of public–private partnerships. It is envisaged that this approach will solve the dual problem of infrastructural barriers and weak ICT policies. As technology is used more in education, the teachers’ roles are increasingly integrated with those of support staff, administrators and technical staff. The needs of e‐learning environments suggest the viability of multistakeholder networks to share expertise and resolve issues related to training needs. The paper concludes that collaboration networks that include e‐learning sponsors, policy makers, telecommunication network service providers and educators are required to solve the problems of online education in Africa.
The Role of Investment, Financing and Dividend Decisions in Explaining Corporate Ownership Structure: Empirical Evidence from Spain
Authors: Pindado Julio , De La Torre Chabela 
Published: October 2006

Abstract This paper analyses the determinants of ownership structure by focusing on the role played by investment, financing and dividend decisions. The use of the Generalised Method of Moments allows us to provide new evidence on this important corporate governance topic, since it controls for the endogeneity problem. Our most relevant findings show that: i) increases in debt lead insiders to limit the risk they bear by reducing their holdings; ii) monitoring by large outside owners substitutes for the disciplinary role of debt; and iii) both inside and outside owners are encouraged to increase their stakes in the firm in view of higher dividends. Our results hold after controlling for equity issues and share repurchases.
The Effect of Family Control on Firm Value and Performance: Evidence from Continental Europe
Authors: Barontini Roberto , Caprio Lorenzo 
Published: October 2006

Abstract We investigate the relation between ownership structure and firm performance in Continental Europe, using data from 675 publicly traded corporations in 11 countries. Although family‐controlled corporations exhibit larger separation between control and cash‐flow rights, our results do not support the hypothesis that family control hampers firm performance. Valuation and operating performance are significantly higher in founder‐controlled corporations and in corporations controlled by descendants who sit on the board as non‐executive directors. When a descendant takes the position of CEO, family‐controlled companies are not statistically distinguishable from non‐family firms in terms of valuation and performance.
The Impact of Corporate Governance on Closed‐end Funds
Authors: Gemmill Gordon , Thomas Dylan C. 
Published: October 2006

Abstract This study uses a large sample of UK‐listed closed‐end funds to examine whether governance has an impact on two indicators of fund performance: the level of fund‐management fees and the discount at which a fund trades. Fees are under the control of the directors, and we find that they are inversely related to fund returns, even after allowing for differences across investment sectors. Fees are, on average, higher if a fund has a large board, few directors from outside the fund‐family, many directors from within the fund‐family, and low ownership by the management company. Discounts for funds are wider if the management company or any blockholder has a significant long‐term stake, suggesting that investors are wary of entrenched management. The results suggest that boards are frequently compromised in their duty to shareholders by their dependence on fund‐management companies.
Innovation that Fits by Michael Lord, Donald DeBethizy, and Jeffrey Wager
Authors: Kingston George 
Published: October 2006

Although accidental, the last three of the reviews in this set follow a theme: They all address high levels of uncertainty and change in projects, which is what one encounters when developing a highly innovative product where the market, customer usage patterns, and the technology are being explored as the product is being developed. First, Roman Pichler reviews a book on agile estimating and planning, which describes agile software development methods applicable to planning and estimating nonsoftware products subject to high rates of change. Next, I review one on managing risk in high‐uncertainty projects. Finally, Carla Kuesten reviews a set of case studies from modern China where change and uncertainty abound.Interestingly, these reviewers follow their own advice, applying a major tool for operating in uncertain situations: iteration. Pichler's review went through eight versions before it was final, and Kuesten topped him at nine. Books reviewed in this issue:

Innovation that Fits
Agile Estimating and Planning
Managing the Unknown: A New Approach to Managing High Uncertainty and Risk in Projects
Made in China: What Western Managers Can Learn from Trailblazing Chinese Entrepreneurs
A time‐dependent effect of PDGF‐BB on adhesion and growth of cultured fibroblasts to root surfaces
Authors: Belal MH , Watanabe H , Ichinose S , Ishikawa I 
Published: October 2006

Objective:  Platelet‐derived growth factor (PDGF‐BB) is suggested to be a potent stimulator and a strong mitogenic agent for human periodontal ligament cells (PDL). This study aimed at assessing the effectiveness of PDGF‐BB application on periodontally diseased root surfaces through attachment and growth of fibroblast cells.Materials and methods:  Fifteen periodontally involved and five healthy teeth were selected, prepared from proximal surfaces and distributed into four groups (10 specimens per group): I: healthy; II: untreated diseased; III: scaling and root planning (SRP); and IV: SRP and PDGF‐BB. Each group had three subdivisions (three specimens per group) which were incubated at three different time periods. The remaining specimen for each group was used to examine surface topography. Fibroblasts were pooled on root specimens and incubated. Results were evaluated by using scanning electron microscopy. Repeated cell counting was done within a representative standard area.Results:  The best results regarding PDL cell shape and density were obtained at day 3 in all experimental groups, except the diseased group. Although SRP samples showed slightly higher results in numbers of attached fibroblasts than diseased samples, they demonstrated a similar negative effect denoting incompatible root surfaces for fibroblast attachment. SRP plus PDGF‐BB and healthy samples showed a comparable positive effect, suggesting a good root surface biocompatibility. Inter‐group differences showed no significant differences on day 1, but statistically significant differences were found on both day 3 and day 7 incubation periods favoring groups I and IV over groups II and III.Conclusions:  Platelet‐derived growth factor showed a positive effect on adhesion and growth of cultured fibroblasts to periodontally diseased surfaces. Thus, PDGF‐BB may have a promising role in clinical periodontics.
Gingival crevicular fluid matrix metalloproteinase‐13 levels and molecular forms in various types of periodontal diseases
Authors: İlgenli T , Vardar‐Sengul S , Gürkan A , Sorsa T , Stackelberg S , Köse T , Atilla G 
Published: October 2006

Background:  The purpose of this study was to evaluate the levels, molecular forms and activation degree of matrix metalloproteinase‐13 (MMP‐13) in the gingival crevicular fluid (GCF) of patients with periodontal diseases and to correlate these findings with periodontal clinical parameters.Methods:  Sixty one subjects participated in this study as healthy (n = 18), gingivitis (n = 17), aggressive periodontitis (AgP; n = 15) and chronic periodontitis (CP; n = 11) groups. Clinical measurements and GCF samples were obtained from each subject. The molecular forms of MMP‐13 in GCF samples were analyzed by Western immunoblotting method. Differences among the groups were assessed using non‐parametric statistical analysis.Results:  In the CP group, levels of 29–30 kDa fragment of MMP‐13, total MMP‐13, and activated form of MMP‐13 were significantly higher than in the healthy, gingivitis and AgP groups. GCF levels of all molecular forms of MMP‐13 in AgP group were similar to those of healthy and gingivitis groups. Total and activated MMP‐13 levels were positively correlated with all clinical parameters. 29–30 kDa fragment levels of MMP‐13 were also positively correlated with papillary bleeding index and plaque index.Conclusion:  These results indicate that elevated GCF MMP‐13 levels may play an important role in the pathogenesis of CP. These data demonstrate, for the first time, pathologically activated and elevated MMP‐13 in GCF.
Removal of Barometric Pressure Effects and Earth Tides from Observed Water Levels
Authors: Toll Nathanial J. , Rasmussen Todd C. 
Published: October 2006

AbstractThe effects of barometric pressure and earth tide changes are often observed in ground water level measurements. These disturbances can make aquifer test interpretation difficult by masking the small changes induced by aquifer testing at late times and great distances. A computer utility is now available that automatically removes the effects of barometric pressure and earth tides from water level observations using regression deconvolution. This procedure has been shown to remove more noise then traditional constant barometric efficiency techniques in both confined and unconfined aquifers. Instead of a single, instantaneous barometric efficiency, the procedure more correctly accounts for the lagged responses caused by barometric pressure and earth tide changes. Simultaneous measurements of water levels (or total heads) and nearby barometric pressures are required. As an additional option, the effects of earth tides can also be removed using theoretical earth tides. The program is demonstrated for two data sets collected at the Waste Isolation Pilot Plant, Carlsbad, New Mexico. The program is available free by request at http://www.hydrology.uga.edu/tools.html.
Porphyromonas gingivalis galEIs Involved in Lipopolysaccharide O-Antigen Synthesis and Biofilm Formation
Authors: Nakao Ryoma , Senpuku Hidenobu , Watanabe Haruo 
Published: October 2006

ABSTRACTPorphyromonas gingivalisis a crucial component of complex plaque biofilms that form in the oral cavity, resulting in the progression of periodontal disease. To elucidate the mechanism of periodontal biofilm formation, we analyzed the involvement of several genes related to the synthesis of polysaccharides inP. gingivalis. Gene knockoutP. gingivalismutants were constructed by insertion of anermF-ermAMcassette; among these mutants, thegalEmutant showed some characteristic phenotypes involved in the loss of GalE activity. As expected, thegalEmutant accumulated intracellular carbohydrates in the presence of 0.1% galactose and did not grow in the presence of galactose at a concentration greater than 1%, in contrast to the parental strain. Lipopolysaccharide (LPS) analysis indicated that the length of the O-antigen chain of thegalEmutant was shorter than that of the wild type. It was also demonstrated that biofilms generated by thegalEmutant had an intensity 4.5-fold greater than those of the wild type. Further, thegalEmutant was found to be significantly susceptible to some antibiotics in comparison with the wild type. In addition, complementation of thegalEmutation led to a partial recovery of the parental phenotypes. We concluded that thegalEgene plays a pivotal role in the modification of LPS O antigen and biofilm formation inP. gingivalisand considered that our findings of a relationship between the function of theP. gingivalis galEgene and virulence phenotypes such as biofilm formation may provide clues for understanding the mechanism of pathogenicity in periodontal disease.
A Newly Identified Leptospiral Adhesin Mediates Attachment to Laminin
Authors: Barbosa Angela S. , Abreu Patricia A. E. , Neves Fernanda O. , Atzingen Marina V. , Watanabe Mônica M. , Vieira Mônica L. , Morais Zenaide M. , Vasconcellos Sílvio A. , Nascimento Ana L. T. O. 
Published: October 2006

ABSTRACT

Pathogenic leptospires have the ability to survive and disseminate to multiple organs after penetrating the host. Several pathogens, including spirochetes, have been shown to express surface proteins that interact with the extracellular matrix (ECM). This adhesin-mediated binding process seems to be a crucial step in the colonization of host tissues. This study examined the interaction of putative leptospiral outer membrane proteins with laminin, collagen type I, collagen type IV, cellular fibronectin, and plasma fibronectin. Six predicted coding sequences selected from the
Leptospira interrogans
serovar Copenhageni genome were cloned, and proteins were expressed, purified by metal affinity chromatography, and characterized by circular dichroism spectroscopy. Their capacity to mediate attachment to ECM components was evaluated by binding assays. We have identified a leptospiral protein encoded by LIC12906, named Lsa24 (leptospiral surface adhesin; 24 kDa) that binds strongly to laminin. Attachment of Lsa24 to laminin was specific, dose dependent, and saturable. Laminin oxidation by sodium metaperiodate reduced the protein-laminin interaction in a concentration-dependent manner, indicating that laminin sugar moieties are crucial for this interaction. Triton X-114-solubilized extract of
L. interrogans
and phase partitioning showed that Lsa24 was exclusively in the detergent phase, indicating that it is a component of the leptospiral membrane. Moreover, Lsa24 partially inhibited leptospiral adherence to immobilized laminin. This newly identified membrane protein may play a role in mediating adhesion of
L. interrogans
to the host. To our knowledge, this is the first leptospiral adhesin with laminin-binding properties reported to date.
The K1 Serotype Capsular Polysaccharide ofPorphyromonas gingivalisElicits Chemokine Production from Murine Macrophages That Facilitates Cell Migration
Authors: d'Empaire Gabriela , Baer Michael T. , Gibson Frank C. 
Published: October 2006

ABSTRACTPorphyromonas gingivalisis the principal organism associated with aggressive forms of generalized periodontal disease. Previous reports have suggested that encapsulatedP. gingivalisstrains are more virulent than unencapsulated strains; however, the contribution of capsular polysaccharide (CPS) to the virulence of this organism is poorly understood. Since periodontal disease presents with a complex inflammatory cell lesion comprised of neutrophils and monocytes, we cultured murine peritoneal macrophages with heat-killedP. gingivalisW83, CPS purified fromP. gingivalisstrain W83, and the seven known serotype-specificP. gingivalisCPS and assessed the ability of supernatant fluids produced by challenged macrophages to attract naïve inflammatory cells. We also defined JE/MCP-1, KC, MIP-2, and RANTES production in response to theP. gingivalisCPS antigens. We observed that supernatant fluids collected from macrophages incubated withP. gingivalisW83 and serotype K1 CPS stimulated the migration of naïve murine bone marrow-derived polymorphonuclear leukocytes in an in vitro cell migration chamber. CPS from W83 and the K1 serotype elicited potent chemokine secretion patterns for macrophages, while those specific to serotypes K2 to K7 were significantly less stimulatory. Reverse transcription-PCR and enzyme-linked immunosorbent assay revealed JE/MCP-1, KC, MIP-2, and RANTES expression from murine macrophages which had been challenged with purifiedP. gingivalisW83 CPS. Chemokine production appeared to be dependent on both the dose of and time of exposure toP. gingivalisW83 CPS. These data demonstrate that theP. gingivalisserotype K1 CPS elicits chemokine production from phagocytic cells. Furthermore, these data suggest that the host response to this antigen may contribute to the formation of the inflammatory cell lesion observed duringP. gingivalis-elicited periodontal disease.
Protection Elicited by Two Glutamine Auxotrophs of
Mycobacterium tuberculosis
and In Vivo Growth Phenotypes of the Four Unique Glutamine Synthetase Mutants in a Murine Model
Authors: Lee Sunhee , Jeon Bo-Young , Bardarov Svetoslav , Chen Mei , Morris Sheldon L. , Jacobs William R. 
Published: October 2006

ABSTRACT

We generated four individual glutamine synthetase (GS) mutants (Δ
glnA1
, Δ
glnA2
, Δ
glnA3
, and Δ
glnA4
) and one triple mutant (Δ
glnA1EA2
) of
Mycobacterium tuberculosis
to investigate the roles of GS enzymes. Subcutaneous immunization with the Δ
glnA1EA2
and Δ
glnA1
glutamine auxotrophic mutants conferred protection on C57BL/6 mice against an aerosol challenge with virulent
M. tuberculosis
, which was comparable to that provided by
Mycobacterium bovis
BCG vaccination.
Interaction of a Neurotropic Strain ofBorrelia turicataewith the Cerebral Microcirculation System
Authors: Sethi Nilay , Sondey Marie , Bai Yunhong , Kim Kwang S. , Cadavid Diego 
Published: October 2006

ABSTRACTRelapsing fever (RF) is a spirochetal infection characterized by relapses of a febrile illness and spirochetemia due to the sequential appearance and disappearance of isogenic serotypes in the blood. The only difference between isogenic serotypes is the variable major outer membrane lipoprotein. In the absence of specific antibody, established serotypes cause persistent infection. Studies in our laboratory indicate that another consequence of serotype switching in RF is a change in neuroinvasiveness. As the next step to elucidate this phenomenon, we studied the interaction of the neurotropic Oz1 strain of the RF agentBorrelia turicataewith the cerebral microcirculation. During persistent infection of antibody-deficient mice, we found that serotype 1 entered the brain in larger numbers and caused more severe cerebral microgliosis than isogenic serotype 2. Microscopic examination revealed binding ofB. turicataeto brain microvascular endothelial cells in vivo. In vitro we found thatB. turicataeassociated with brain microvascular endothelial cells (BMEC) significantly more than with fibroblasts or arachnoidal cells. The binding was completely eliminated by pretreatment of BMEC with proteinase K. Using transwell chambers with BMEC barriers, we found that serotype 1 crossed into the lower compartment significantly better than serotype 2. Heat killing significantly reduced BMEC crossing but not binding. We concluded that the interaction ofB. turicataewith the cerebral microcirculation involves both binding and crossing brain microvascular endothelial cells, with significant differences among isogenic serotypes.