bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular interactions of alanine‐rich and proline‐rich regions of cell surface protein antigen c in Streptococcus mutans
Authors: Matsumoto‐Nakano M. , Tsuji M. , Amano A. , Ooshima T. 
Published: June 2008

Introduction:  Streptococcus mutans has been implicated as a primary causative agent of dental caries in humans, and its cell surface protein antigen c (PAc) is known to be associated with sucrose‐independent adhesion to tooth surfaces. PAc is composed of several domains, including an N‐terminal signal sequence, an alanine‐rich repeat region (A‐region), a proline‐rich repeat region (P‐region), and an anchor region.Methods:  To investigate the functions of each domain, an A‐region‐deficient mutant strain of S. mutans was constructed, and recombinant PAc and A‐ and P‐region proteins were also constructed. The interactions of each domain with the recombinant proteins were analyzed using surface plasmon resonance spectroscopy with a biomolecular interaction analyzing system.Results:  The A‐region‐deficient mutant strain showed the lowest levels of adherence to saliva‐coated hydroxyapatite. Furthermore, findings in an immunoblot assay indicated that the A‐region protein reacted strongly with proline‐rich proteins in saliva, while the recombinant P‐region protein interacted more quickly with PAc than the recombinant A‐region protein.Conclusion:  These results suggest that the A‐region has a strong relationship with adhesion to tooth surfaces, while the P‐region has a high affinity for PAc.
Molecular analysis of the root canal microbiota associated with endodontic treatment failures
Authors: Sakamoto M. , Siqueira Jr J. F. , Rôças I. N. , Benno Y. 
Published: June 2008

Introduction:  The failure of endodontic treatment is usually caused by persistent/secondary intraradicular infections and Enterococcus faecalis has been considered to be the main pathogen involved. Nevertheless, the breadth of bacterial diversity involved with endodontic treatment failures remains to be consistently explored by culture‐independent approaches.Methods:  This study determined the intraradicular microbiota of root‐canal‐treated teeth with post‐treatment apical periodontitis using 16S ribosomal RNA gene clone library analysis.Results:  Bacteria were present in all cases, confirming the infectious etiology of post‐treatment disease. Seventy‐four bacterial taxa belonging to six phyla were found in the nine cases investigated. Of these, 55% were identified as as‐yet‐uncultivated phylotypes, which also made up a significant proportion of the microbiota in many cases. Twenty‐five new phylotypes were identified. Most teeth harbored a mixed consortium, with a mean number of 10 taxa per case. Only 11 taxa were found in more than one case, revealing a high interindividual variability in the composition of the microbiota.Conclusion:  The current findings revealed new candidate endodontic pathogens, including as‐yet‐uncultivated bacteria and taxa other than E. faecalis, which may participate in the mixed infections associated with post‐treatment apical periodontitis.
Expression patterns of genes induced by oxidative stress in Porphyromonas gingivalis
Authors: Meuric V. , Gracieux P. , Tamanai‐Shacoori Z. , Perez‐Chaparro J. , Bonnaure‐Mallet M. 
Published: June 2008

Introduction:  Porphyromonas gingivalis, a gram‐negative anaerobic bacterium, is a major periopathogen whose transmission from host to host involves exposure to atmospheric oxygen. P. gingivalis contains genetic factors that function in an oxidative stress response, but their expression has not been analyzed during exposure to atmospheric oxygen. The aim of this study was to obtain a better understanding of atmospheric adaptation of P. gingivalis.Methods:  The aerotolerance of wild‐type and oxyR mutant P. gingivalis strains were determined, and quantitative polymerase chain reaction was performed to analyze gene expression patterns in response to exposure to atmospheric oxygen. The analyzed P. gingivalis genes encoded proteins involved in oxidative response (oxyR, ahpC‐F, batA, dps, ftn, tpx) as well as several major virulence factors (hagA, hagB, hagE, rgpA, rgpB, hem).Results:  Our results demonstrated a critical role for the oxyR gene in the aerotolerance of P. gingivalis. The ahpC‐F, batA, and hem genes were slightly overexpressed (between 1.65‐fold and 2‐fold) after exposure to atmospheric oxygen compared to anaerobic conditions. The level of transcription of dps, ftn, tpx, and rgpA genes increased more than 2.5‐fold, and the expression of ahpC‐F, dps, ftn, and tpx was partially or completely OxyR‐dependent.Conclusion:  A different transcription pattern of P. gingivalis genes was observed, depending on the stimulus of oxidative stress. We present new evidence that the expression of tpx, encoding a thiol peroxidase, is partially OxyR‐dependent and is induced after atmospheric oxygen exposure.
CCL20 production is induced in human dental pulp upon stimulation by Streptococcus mutans and proinflammatory cytokines
Authors: Takahashi K. , Nakanishi T. , Yumoto H. , Adachi T. , Matsuo T. 
Published: June 2008

Introduction:  Pulpitis is characterized by the marked infiltration of inflammatory cells in response to an invasion of caries‐related bacteria. It is well known that chemokines regulate the trafficking of lymphocytes, and CC chemokine ligand 20 (CCL20) has been recently shown to play a crucial role in the recruitment of memory T cells and immature dendritic cells into inflammatory lesions. We previously reported that CCL20 was mainly expressed in microvascular endothelial cells and macrophages that accumulated in inflamed pulp tissues and that its specific receptor, CCR6, was expressed on infiltrated lymphocytes. However, the mechanism of CCL20 expression remains unclear.Methods and Results:  In this study, we investigated the expression of CCL20 in monocytes/macrophages, endothelial cells, and pulpal fibroblasts after stimulation with Streptococcus mutans, a representative of caries‐related bacteria, or proinflammatory cytokines. CCL20 messenger RNA was detected by reverse transcription–polymerase chain reaction in inflamed pulp, but not in clinically normal pulp. By enzyme‐linked immunosorbent assay, S. mutans induced a human monocytic cell line, differentiated macrophage‐like THP‐1 cells, and human umbilical vein endothelial cells (HUVEC) to produce an increased amount of CCL20. Lipoteichoic acid from S. mutans also elicited CCL20 production by HUVEC. Moreover, CCL20 production from pulpal fibroblasts was increased by stimulation with inetrleukin‐1β and tumor necrosis factor‐α.Conclusion:  Our results indicate that CCL20 expression is induced by stimulation with caries‐related bacteria that have invaded deeply into the dentinal tubules as well as by proinflammatory cytokines in the inflamed pulpal lesions. It may be involved in the progression of pulpitis via accumulation of inflammatory cells.
Analysis of neutrophil‐derived antimicrobial peptides in gingival crevicular fluid suggests importance of cathelicidin LL‐37 in the innate immune response against periodontogenic bacteria
Authors: Puklo M. , Guentsch A. , Hiemstra P. S. , Eick S. , Potempa J. 
Published: June 2008

Introduction:  During periodontitis, an innate immune response to bacterial challenge is primarily mediated by neutrophils. We compared neutrophilic content and the level of neutrophil‐derived antimicrobial peptides in gingival crevicular fluid (GCF) in two clinical forms of severe periodontitis.Methods:  GCF was collected from 14 patients with aggressive periodontitis, 17 patients with chronic periodontitis, and nine healthy subjects. Samples were analyzed for periodontopathogen load using real‐time polymerase chain reactions. The amounts of myeloperoxidase and α‐defensins (HNP1–3) were determined by enzyme‐linked immunosorbent assay, and the level of cathelicidin (hCAP18/LL‐37) was assayed by Western blot.Results:  Myeloperoxidase concentration was not correlated with levels of LL‐37 and HNP1–3 in samples from patients, compared to controls. The amount of HNP1–3 was twofold and fourfold higher in patients with aggressive and chronic periodontitis, respectively. Those with chronic disease had significantly elevated amounts of mature LL‐37. The increased concentration of both peptides in chronic periodontitis correlated with the load of Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola.Conclusion:  The lack of a correlation between LL‐37, HNP1–3, and myeloperoxidase content suggests that neutrophils are not the sole source of these bactericidal peptides in the GCF of patients with periodontitis; and that other cells contribute to their local production. The bacterial proteases of P. gingivalis, T. forsythia, and T. denticola might degrade hCAP18/LL‐37, because the 11‐kDa cathelicidin‐derived fragment was present in GCF collected from pockets infected with these bacteria. Collectively, it appears that a local deficiency in LL‐37 can be considered as a supporting factor in the pathogenesis of severe cases of periodontitis.
Are there interactive effects of mate availability and predation risk on life history and defence in a simultaneous hermaphrodite?
Authors: AULD J. R. , RELYEA R. A. 
Published: June 2008

AbstractEncountering mates and avoiding predators are ubiquitous challenges faced by many organisms and they can affect the expression of many traits including growth, timing of maturity and resource allocation to reproduction. However, these two factors are commonly considered in isolation rather than simultaneously. We examined whether predation risk and mate availability interact to affect morphology and life‐history traits (including lifetime fecundity) of a hermaphroditic snail (Physa acuta). We found that mate availability reduced juvenile growth rate and final size. Predator cues from crayfish induced delayed reproduction, but there were no reduced fecundity costs associated with predator induction. Although there were interactive effects on longevity, lifetime fecundity was determined by the number of reproductive days. Therefore, our results indicate a resource‐allocation trade‐off among growth, longevity and reproduction. Future consideration of this interaction will be important for understanding how resource‐allocation plasticity affects the integration of defensive, life‐history and mating‐system traits.
Should food‐deceptive species flower before or after rewarding species? An experimental test of pollinator visitation behaviour under contrasting phenologies
Authors: INTERNICOLA A. I. , BERNASCONI G. , GIGORD L. D. B. 
Published: June 2008

AbstractMany plant species reward their pollinators, whereas some species, particularly among orchids, do not. Similarity of floral cues between co‐flowering species influences how rapidly pollinators learn to avoid deceptive plants. This learning process, which affects the reproductive success of deceptive plants, may additionally depend on relative timing of flowering of sympatric rewarding and deceptive species. We tested the combined effects of corolla colour similarity and flowering order of rewarding and deceptive artificial inflorescences on visitation by naïve bumblebees. When deceptive inflorescences were offered after rewarding inflorescences, bumblebees visited them four times more often if both species were similar compared with when they were dissimilar. Pollinator visitation rate to deceptive inflorescences offered before rewarding inflorescences was intermediate and independent of similarity. Thus, early‐flowering deceptive species avoid the costs of dissimilarity with rewarding species. This mechanism may favour adaptive evolution of flowering phenology in deceptive species and explain why temperate deceptive orchids usually flower earlier than rewarding ones.
A change in climate causes rapid evolution of multiple life‐history traits and their interactions in an annual plant
Authors: FRANKS S. J. , WEIS A. E. 
Published: June 2008

AbstractClimate change is likely to spur rapid evolution, potentially altering integrated suites of life‐history traits. We examined evolutionary change in multiple life‐history traits of the annual plantBrassica rapacollected before and after a recent 5‐year drought in southern California. We used a direct approach to examining evolutionary change by comparing ancestors and descendants. Collections were made from two populations varying in average soil moisture levels, and lines propagated from the collected seeds were grown in a greenhouse and experimentally subjected to conditions simulating either drought (short growing season) or high precipitation (long growing season) years. Comparing ancestors and descendants, we found that the drought caused many changes in life‐history traits, including a shift to earlier flowering, longer duration of flowering, reduced peak flowering and greater skew of the flowering schedule. Descendants had thinner stems and fewer leaf nodes at the time of flowering than ancestors, indicating that the drought selected for plants that flowered at a smaller size and earlier ontogenetic stage rather than selecting for plants to develop more rapidly. Thus, there was not evidence for absolute developmental constraints to flowering time evolution. Common principal component analyses showed substantial differences in the matrix of trait covariances both between short and long growing season treatments and between populations. Although the covariances matrices were generally similar between ancestors and descendants, there was evidence for complex evolutionary changes in the relationships among the traits, and these changes depended on the population and treatment. These results show that a full appreciation of the impacts of global change on phenotypic evolution will entail an understanding of how changes in climatic conditions affect trait values and the structure of relationships among traits.
Efficient replacing of fetal bovine serum with human platelet releasate during propagation and differentiation of human bone marrow‐derived mesenchymal stem cells to functional hepatocytes‐like cells
Authors: Kazemnejad S. , Allameh A. , Gharehbaghian A. , Soleimani M. , Amirizadeh N. , Jazayeri M. 
Published: June 2008

Objectives  The aim of this study was to find out substitution effect of fetal bovine serum (FBS) with human platelet releasate (HPR) as a major growth factor source during expansion and differentiation of human bone marrow‐derived mesenchymal stem cells (hBMSC) into hepatocytes.Methods  Propagation and differentiation potential of hBMSCs into hepatocyte‐like cells in a medium fortified with HPR instead of FBS were investigated with morphological, cytochemical and molecular experiments.Results  Multiplex analysis showed that HPR was more efficient than FBS in supporting hBMSC outgrowth. The proliferation rate of MSC in presence of HPR (derived from 109 platelets/ml) was about threefold greater than that of FBS (P < 0·001). Despite the differences in MTT value, hBMSCs‐driven HPR or FBS did not differ in terms of gross morphology, immunophenotype and osteogenic differentiation potential. Hepatic differentiation of hBMSCs was successfully performed in the media enriched with HPR. Immunoreactivity of cells with monoclonal antibodies against for albumin and α‐fetoprotein (AFP) was even more positive in hepatocytes differentiated in presence of HPR as compared to that of FBS. The gene expression of albumin, AFP and cytokeratin‐18 at mRNA levels in differentiated cells attest to supporting role of HPR in hepatic differentiation media. These findings were further confirmed with greater urea production (approximately twofold) in the culture media of cells differentiated under HPR compared to that in FBS (P < 0·001).Conclusion  Human platelet releasate is an efficient and safe substitute for FBS in culture media used for expansion and differentiation of hBMSCs to hepatocyte.
5‐Azacytidine‐treated human mesenchymal stem/progenitor cells derived from umbilical cord, cord blood and bone marrow do not generate cardiomyocytes in vitro at high frequencies
Authors: Martin‐Rendon E. , Sweeney D. , Lu F. , Girdlestone J. , Navarrete C. , Watt S. M. 
Published: June 2008

Background and Objectives  Mesenchymal stem/progenitor cells (MSCs) are multipotent progenitors that differentiate into such lineages as bone, fat, cartilage and stromal cells that support haemopoiesis. Bone marrow MSCs can also contribute to cardiac repair, although the mechanism for this is unclear. Here, we examine the potential of MSCs from different sources to generate cardiomyocytes in vitro, as a means for predicting their therapeutic potential after myocardial infarction.Materials and Methods  Mesenchymal stem/progenitor cells were isolated from the perivascular tissue and Wharton's jelly of the umbilical cord and from cord blood. Their immunophenotype and differentiation potential to generate osteoblasts, chondrocytes, adipocytes and cardiomyoxcytes in vitro was compared with those of bone marrow MSCs.Results  Mesenchymal stem/progenitor cells isolated from umbilical cord and cord blood were phenotypically similar to bone marrow MSCs, the exception being in the expression of CD106, which was absent on umbilical cord MSCs, and CD146 that was highly expressed in cord blood MSCs. They have variable abilities to give rise to osteoblasts, chondrocytes and adipocytes, with bone marrow MSCs being the most robust. While a small proportion (~0·07%) of bone marrow MSCs could generate cardiomyocyte‐like cells in vitro, those from umbilical cord and cord blood did not express cardiac markers either spontaneously or after treatment with 5‐azacytidine.Conclusion  Although MSCs may be useful for such clinical applications as bone or cartilage repair, the results presented here indicate that such cells do not generate cardiomyocytes frequently enough for cardiac repair. Their efficacy in heart repair is likely to be due to paracrine mechanisms.
ADAMTS‐13 activity and von Willebrand factor levels in methylene blue photo‐inactivated plasma processed by either the Springe method or an ‘in house’ system
Authors: Del Río‐Garma J. , Pereira A. , Arroyo J. L. , Mateo J. , Alvarez‐Larrán A. , Martínez C. , Muncunill J. , Barbolla L. ,   on behalf of the Spanish Group of Apheresis (Grupo Español de Aféresis GEA)
Published: June 2008

Background and Objectives Methylene blue photo‐inactivated plasma (MBPIP) has been reported to be less effective than fresh‐frozen plasma (FFP) in the treatment of thrombotic thrombocytopenic purpura, which suggests a reduced content of the von Willebrand factor metalloprotease ADAMTS‐13 in MBPIP.Materials and Methods ADAMTS‐13 activity and von Willebrand factor antigen (vWF:Ag) levels were measured in plasma before and after photo‐oxidation by either the Springe method or a commercial ‘in house’ system as well as in cryoprecipitate‐poor plasma (CPP) and FFP (20 units each).Results Levels of ADAMTS‐13 activity in MBPIP processed by the Springe method or the commercial ‘in house’ system were comparable to one another and did not significantly differ from levels found in FFP [median (range): 114% (57–139%), 99% (74–123%), and 106% (70–130%), respectively]. ADAMTS‐13 activity was significantly reduced in CPP [median (range): 87% (70–107%) as compared with FFP (P < 0·05). Levels of vWF:Ag decreased after photo‐oxidation by both methods.Conclusion In vitroADAMTS‐13 activity was conserved in MBPIP processed by the two photo‐oxidation methods analysed and did not significantly differ from levels found in FFP.
A quinclorac sensitive lethality rice mutant: its discovery, genetics and potential application
Authors: Peng H. , Zhang J. , Xie Q. 
Published: June 2008

AbstractIn this study, we reported a quinclorac‐sensitive rice natural mutant M4017, derived from an indica restorer line 4017 of three‐line hybrid. The mutant could be killed at three‐leaf stage by quinclorac at 175 mg/l or higher, a dosage that is recommended for monocot herbs control. The mutant at flowering stages can also be effectively killed by quinclorac at 1.25–1.50 g/l or higher, which is safe for its F1 hybrids and all other normal varieties. Genetic analysis, using the F1, F2 and BC1 populations derived from this mutant and other often‐used varieties, revealed that quinclorac sensitivity/lethality was controlled by a single recessive gene, which was named quin1. This mutant has a potential application in false hybrid seed removal or mechanized production of hybrid seeds.
Multi‐environment evaluation of level and stability of FHB resistance among parental lines and selected offspring derived from several European winter wheat mapping populations
Authors: Buerstmayr H. , Lemmens M. , Schmolke M. , Zimmermann G. , Hartl L. , Mascher F. , Trottet M. , Gosman N. E. , Nicholson P. 
Published: June 2008

AbstractDuring 2 years and at five locations in Europe, 56 winter wheat genotypes were evaluated for resistance to Fusarium head blight (FHB). The genotypes were both parents and selected recombinants taken from the following populations previously tested for FHB resistance: ‘Arina’/‘Forno’, ‘Arina’/‘Riband’, ‘Dream’/‘Lynx’, G16‐92/‘Hussar’, ‘Renan’/‘Récital’, SVP‐72017 × ‘Capo’ and ‘Capo’/‘Sumai‐3’. In addition, a few control lines were included. FHB resistance was evaluated in replicated experiments under artificial inoculation, disease severity was assessed by repeated visual scorings. The highest level of FHB resistance was found in lines selected from crosses of FHB‐resistant winter wheat × ‘Sumai‐3’. The best lines selected from crosses of moderately resistant winter wheat with susceptible winter wheat were similar in their resistance response to the resistant parent. The level of FHB resistance was correlated with stability of resistance. Susceptible wheat lines tended to exhibit severe symptoms under high disease pressure. The symptoms on resistant lines remained comparatively low even under high disease pressure.
Diversity and geographical distribution of seed lipoxygenase‐1 thermostability types in barley
Authors: Hirota N. , Kaneko T. , Ito K. , Takeda K. 
Published: June 2008

AbstractTo understand the diversity in the thermostability of the seed lipoxygenase‐1 (LOX‐1), 1040 cultivars of worldwide barley (Hordeum vulgare ssp. vulgare) genetic resources were investigated. The relative thermostability of LOX‐1 (LOX‐RTS) in these lines showed a bimodal frequency distribution and these lines were categorized into the high and low thermostability types (H‐type and L‐type, respectively). The H‐type lines predominated in the wild progenitor, ssp. spontaneum. The geographical distribution of these types in the cultivars was surveyed. The frequencies of the H‐ and L‐types were almost equal to one another in southwestern Asia. The occurrence of the H‐type predominated in eastern Asia and Africa, whereas in Europe and Turkey, the L‐type did. The predominance of the L‐type in Europe and Turkey can be understood through the hypothesis that the Fertile Crescent domestication contributed the majority of diversity in Europe. The uneven geographical distribution of the LOX‐1 thermostability types in the cultivars may reflect a polyphyletic origin of barley.