bluuebunny/crossref_metadata_2025_split huggingface dataset:
Significance of primary stability for osseointegration of dental implants
Authors: Lioubavina‐Hack Natalia , Lang Niklaus P. , Karring Thorkild 
Published: March 2006

AbstractAim: To investigate the significance of the initial stability of dental implants for the establishment of osseointegration in an experimental capsule model for bone augmentation.Material and methods: Sixteen male rats were used in the study. In each rat, muscle‐periosteal flaps were elevated on the lateral aspect of the mandibular ramus on both sides, resulting in exposure of the bone surface. Small perforations were then produced in the ramus. A rigid, hemispherical Teflon® capsule with a diameter of 6 mm and a height of 4 mm and with a hole in its middle portion, prepared to fit the circumference of an ITI® HC titanium implant of 2.8 mm in diameter, was fixed to the ramus using 4 mini‐screws. On one side of the jaw, the implant was placed through the hole in such a way that its apex did not make contact with the mandibular ramus (test). This placement of the implant did not ensure primary stability. On the other side of the jaw, a similar implant was placed through the hole of the capsule in such a way that contact was made between the implant and the surface of the ramus (control). This provided primary stability of the implant. After placement of the implants, the soft tissues were repositioned over the capsules and sutured. After 1, 3, 6 and 9 months, four animals were sacrificed and subjected to histometric analysis.Results: The mean height of direct bone‐to‐implant contact of implants with primary stability was 38.8%, 52.9%, 64.6% and 81.3% of the implant length at 1, 3, 6 and 9 months, respectively. Of the bone adjacent to the implant surface, 28.1%, 28.9%, 52.6% and 69.6%, respectively, consisted of mineralized bone. At the test implants, no bone‐to‐implant contact was observed at any observation time or in any of these non‐stabilized specimens.Conclusion: The findings of the present study indicate that primary implant stability is a prerequisite for successful osseointegration, and that implant instability results in fibrous encapsulation, thus confirming previously made clinical observations.
Systemic arteriopathy in SIV‐infected rhesus macaques (Macaca mulatta)
Authors: Yanai Tokuma , Lackner Andrew A. , Sakai Hiroki , Masegi Toshiaki , Simon Meredith A. 
Published: March 2006

AbstractBackground  Severe disseminated vasculopathy was observed in two simian immunodeficiency virus (SIV)‐infected rhesus macaques (Macaca mulatta). These animals developed clinical signs of AIDS, including lymphadenopathy, weight loss, diarrhea and collapse.Results and discussion  Grossly, both animals showed emaciation, lymphadenopathy, vegetations on the mitral valve, renal infarcts and a dilated intestine; one animal had multifocal hemorrhages in multiple organs. Histologically, both cases had disseminated arteriopathy characterized by intimal thickening and fibrosis with varying degrees of vasculitis. The lesion was prominent in the kidney, intestine, pancreas, liver, heart, lymph nodes, spleen and testis. Occasional venules had intimal thickening. Both cases had cytomegalovirus (CMV) infection with intranuclear inclusions, CMV antigen and nucleic acid; some inclusions were observed in endothelial cells within some of the vascular lesions in one of the two. These data suggest that CMV caused the unusual lesions.
Evidence Base for Practice: Reduction of Restraint and Seclusion Use During Child and Adolescent Psychiatric Inpatient Treatment
Authors: Delaney Kathleen R. 
Published: March 2006

ABSTRACT Background: Restraint and seclusion of children has great potential for harm. Since the mid‐1980s, psychiatric inpatient personnel for children and adolescents have put considerable energy in reducing the use of extreme measures of aggression management. While the use of restraints is a particular problem in the United States, aggression management and means of control in psychiatric settings is an international issue. Approach: The core question of this review was: What is the current state of the evidence supporting restraint reduction efforts with children and adolescents? Studies were reviewed and critiqued that related to programs of restraint reduction, restraint reduction methods, and aggression management. Internationally, there seems to be more emphasis on reducing coercive measures by understanding the context of their use. Thus, studies exploring staff perceptions and decisions concerning coercive measures were also examined. Findings: The evidence supporting restraint reduction methods in the United States comes mainly from case study reports of clinical sites' quality improvement projects. Consequently, a collection of studies is accumulating that supports a multi‐strategy approach to restraint reduction. Limited evidence exists for aggression management measures and training in de‐escalation techniques. Controversial aggression management techniques such as the use of pro re nata medication and holding continue to be used with very little support for their efficacy. Recommendations: Recommendations include taking a view of restraint and seclusion as emergency measures to address dangerous aggression, not interventions examined in controlled studies. As such it is suggested that sites pool data on restraint use and reduction efforts to create a database for benchmarking and studying variations among hospitals. Furthermore, attention should also be given to developing additional means for addressing aggressive behaviors. Worldviews on Evidence‐Based Nursing 2006; 3(1):19‐30
Evidence of Dichogamy in Santalum album L.
Authors: Ma Guo‐Hua , Bunn Eric , Zhang Jing‐Feng , Wu Guo‐Jiang 
Published: March 2006

AbstractFlowering, fruit set, embryological development, and pollination trials were investigated in Santalum album L. Each ovary may have three to four ovules. Microsporogenesis and megasporogenesis in the same flower were synchronized at the earlier stages of flower development. However, at anthesis, when pollen was mature, the magaspore had developed only to the stage of a one‐ to two‐nucleus embryo sac. As the eight‐nucleus embryo sac developed, some mamelon cells began to undergo programmed cell death, forming holes into which the eight‐nucleus embryo sacs extended, becoming “N” or “S” shaped. The development from a two‐nucleus embryo sac to a matured eight‐nucleus embryo sac lasted up to 10 d. Fruit‐set from open pollination was less than 2%. The endosperm develops prior to division of the zygotic embryo and one to three embryos and endosperms were formed in the same fruit. A mature seed usually germinates to produce one seedling; however, two and three seedlings from one seed were also observed, albeit at a low frequency. Pollination trials showed that no seed sets when inflorescences were covered with a bag; however, artificial pollination could improve fruit set. Our pollination trials and embryological studies proved that the flower of S. album is dichogamous and fruit set has high heterozygosity.(Managing editor: Wei Wang)
Differentiation of a Miniature Inverted Transposable Element (MITE) System in Asian Rice Cultivars and Its Inference for a Diphyletic Origin of Two Subspecies of Asian Cultivated Rice
Authors: Hu Hao , Mu Jie , Zhang Hong‐Ji , Tao Yue‐Zhi , Han Bin 
Published: March 2006

AbstractIn the present study, we report a survey on a Miniature Inverted Transposable Element (MITE) system known as mPing in 102 varieties of Asian cultivated rice (Oryza sativa L.). We found that mPing populations could be generalized into two families, mPing‐1 and mPing‐2, according to their sequence structures. Further analysis showed that these two families of mPing had significant bias in their distribution pattern in two subspecies of rice, namely O. sativa ssp. japonica and indica. O. sativa japonica has a higher proportion of mPing‐1 as a general trait, whereas O. sativa indica has a higher proportion of mPing‐2. We also examined the mPing system in a doubled haploid (DH) cross‐breeding population of jingxi 17 (japonica) and zhaiyeqing 8 (indica) varieties and observed that the mPing system was not tightly linked to major subspecies‐determining genes. Furthermore, we checked the mPing system in 28 accessions of Asian common wild rice O. rufipogon and found the mPing system in O. rufipogon. The distribution pattern of the mPing system in O. rufipogon indicated a diphyletic origin of the Asian cultivated rice O. sativa species. We did not find the mPing system in another 20 Oryza species. These results substantiated a previous hypothesis that O. rufipogon and O. nivara species were the closest relatives of O. sativa and that the two extant subspecies of O. sativa were evolved independently from corresponding ecotypes of O. rufipogon.(Managing editor: Li‐Hui Zhao)
Novel Partial Reductive Pathway for 4-Chloronitrobenzene and Nitrobenzene Degradation inComamonassp. Strain CNB-1
Authors: Wu Jian-feng , Jiang Cheng-ying , Wang Bao-jun , Ma Ying-fei , Liu Zhi-pei , Liu Shuang-jiang 
Published: March 2006

ABSTRACTComamonassp. strain CNB-1 grows on 4-chloronitrobenzene (4-CNB) and nitrobenzene as sole carbon and nitrogen sources. In this study, two genetic segments,cnbB-orf2-cnbAandcnbR-orf1-cnbCaCbDEFGHI, located on a newly isolated plasmid, pCNB1 (ca. 89 kb), and involved in 4-CNB/nitrobenzene degradation, were characterized. Seven genes (cnbA,cnbB,cnbCa,cnbCb,cnbD,cnbG, andcnbH) were cloned and functionally expressed in recombinantEscherichia coli, and they were identified as encoding 4-CNB nitroreductase (CnbA), 1-hydroxylaminobenzene mutase (CnbB), 2-aminophenol 1,6-dioxygenase (CnbCab), 2-amino-5-chloromuconic semialdehyde dehydrogenase (CnbD), 2-hydroxy-5-chloromuconic acid (2H5CM) tautomerase, and 2-amino-5-chloromuconic acid (2A5CM) deaminase (CnbH). In particular, the 2A5CM deaminase showed significant identities (31 to 38%) to subunit A of Asp-tRNAAsn/Glu-tRNAGlnamidotransferase and not to the previously identified deaminases for nitroaromatic compound degradation. Genetic cloning and expression ofcnbHinEscherichia colirevealed that CnbH catalyzed the conversion of 2A5CM into 2H5CM and ammonium. Four other genes (cnbR,cnbE,cnbF, andcnbI) were tentatively identified according to their high sequence identities to other functionally identified genes. It was proposed that CnbH might represent a novel type of deaminase and be involved in a novel partial reductive pathway for chloronitrobenzene or nitrobenzene degradation.
Human and Animal Enteric Caliciviruses in Oysters from Different Coastal Regions of the United States
Authors: Costantini Veronica , Loisy Fabienne , Joens Lynn , Le Guyader Françoise S. , Saif Linda J. 
Published: March 2006

ABSTRACT
Food-borne diseases are a major cause of morbidity and hospitalization worldwide. Enteric caliciviruses are capable of persisting in the environment and in the tissues of shellfish. Human noroviruses (HuNoVs) have been implicated in outbreaks linked to shellfish consumption. The genetic and antigenic relatedness between human and animal enteric caliciviruses suggests that interspecies transmission may occur. To determine the occurrence of human and animal enteric caliciviruses in United States market oysters, we surveyed regional markets. Oysters were collected from 45 bays along the United States coast during the summer and winter of 2002 and 2003. Samples were analyzed by reverse transcription-PCR, and results were confirmed by hybridization and sequence analysis. Nine samples (20%) were positive for HuNoV genogroup II after hybridization. Animal enteric caliciviruses were detected in 10 samples (22%). Seven of these samples were positive for porcine norovirus genogroup II, and one sample was positive for porcine sapovirus after hybridization and confirmation by sequencing. Bovine noroviruses were detected in two samples, and these results were confirmed by sequencing. Five HuNoV samples sequenced in the polymerase region were similar to the norovirus genogroup II US 95/96 subset (genogroup II-4) previously implicated in diarrhea outbreaks. Different seasonal and state distributions were detected. The presence of animal enteric caliciviruses was associated with states with high livestock production. Although the presence of human caliciviruses in raw oysters represents a potential risk for gastroenteritis, disease confirmation by investigation of outbreaks is required. The simultaneous detection of human and animal enteric caliciviruses raises concerns about human infection or coinfection with human and animal strains that could result in genomic recombination and the emergence of new strains.
Enhanced Exopolymer Production and Chromium Stabilization inPseudomonas putidaUnsaturated Biofilms
Authors: Priester John H. , Olson Scott G. , Webb Samuel M. , Neu Mary P. , Hersman Larry E. , Holden Patricia A. 
Published: March 2006

ABSTRACTChromium-contaminated soils threaten surface and groundwater quality at many industrial sites. In vadose zones, indigenous bacteria can reduce Cr(VI) to Cr(III), but the subsequent fate of Cr(III) and the roles of bacterial biofilms are relatively unknown. To investigate, we culturedPseudomonas putida, a model organism for vadose zone bioremediation, as unsaturated biofilms on membranes overlaying iron-deficient solid media either containing molecular dichromate from potassium dichromate (Cr-only treatment) or with deposits of solid, dichromate-coated hematite (Fe+Cr treatment) to simulate vadose zone conditions. Controls included iron-deficient solid medium and an Fe-only treatment using solid hematite deposits. Under iron-deficient conditions, chromium exposure resulted in lower cell yield and lower amounts of cellular protein and carbohydrate, but providing iron in the form of hematite overcame these toxic effects of Cr. For the Cr and Fe+Cr treatments, Cr(VI) was completely reduced to Cr(III) that accumulated on biofilm cells and extracellular polymeric substances (EPSs). Chromium exposure resulted in elevated extracellular carbohydrates, protein, DNA, and EPS sugars that were relatively enriched inN-acetyl-glucosamine, rhamnose, glucose, and mannose. The proportions of EPS protein and carbohydrate relative to intracellular pools suggested Cr toxicity-mediated cell lysis as the origin. However, DNA accumulated extracellularly in amounts far greater than expected from cell lysis, and Cr was liberated when extracted EPS was treated with DNase. These results demonstrate that Cr accumulation in unsaturated biofilms occurs with enzymatic reduction of Cr(VI), cellular lysis, cellular association, and extracellular DNA binding of Cr(III), which altogether can facilitate localized biotic stabilization of Cr in contaminated vadose zones.
Gene Expression Regulation by the Curli Activator CsgD Protein: Modulation of Cellulose Biosynthesis and Control of Negative Determinants for Microbial Adhesion
Authors: Brombacher Eva , Baratto Andrea , Dorel Corinne , Landini Paolo 
Published: March 2006

ABSTRACTCurli fibers, encoded by thecsgBACgenes, promote biofilm formation inEscherichia coliand other enterobacteria. Curli production is dependent on the CsgD transcription activator, which also promotes cellulose biosynthesis. In this study, we investigated the effects of CsgD expression from a weak constitutive promoter in the biofilm formation-deficient PHL565 strain ofE. coli. We found that despite its function as a transcription activator, the CsgD protein is localized in the cytoplasmic membrane. Constitutive CsgD expression promotes biofilm formation by PHL565 and activates transcription from thecsgBACpromoter; however,csgBACexpression remains dependent on temperature and the growth medium. Constitutive expression of the CsgD protein results in altered transcription patterns for at least 24 novel genes, in addition to the previously identified CsgD-dependent genes. ThecspAandfecRgenes, encoding regulatory proteins responding to cold shock and to iron, respectively, andyoaD, encoding a putative negative regulator of cellulose biosynthesis, were found to be some of the novel CsgD-regulated genes. Consistent with the predicted functional role, increased expression of theyoaDgene negatively affects cell aggregation, whileyoaDinactivation results in stimulation of cell aggregation and leads to increased cellulose production. Inactivation offecRresults in significant increases in both cell aggregation and biofilm formation, while the effects ofcspAare not as strong in the conditions tested. Our results indicate that CsgD can modulate cellulose biosynthesis through activation of theyoaDgene. In addition, the positive effect of CsgD on biofilm formation might be enhanced by repression of thefecRgene.
A Complete Lipopolysaccharide Inner Core Oligosaccharide Is Required for Resistance of
Burkholderia cenocepacia
to Antimicrobial Peptides and Bacterial Survival In Vivo
Authors: Loutet Slade A. , Flannagan Ronald S. , Kooi Cora , Sokol Pamela A. , Valvano Miguel A. 
Published: March 2006

ABSTRACT

Burkholderia cenocepacia
is an important opportunistic pathogen of patients with cystic fibrosis. This bacterium is inherently resistant to a wide range of antimicrobial agents, including high concentrations of antimicrobial peptides. We hypothesized that the lipopolysaccharide (LPS) of
B. cenocepacia
is important for both virulence and resistance to antimicrobial peptides. We identified
hldA
and
hldD
genes in
B. cenocepacia
strain K56-2. These two genes encode enzymes involved in the modification of heptose sugars prior to their incorporation into the LPS core oligosaccharide. We constructed a mutant, SAL1, which was defective in expression of both
hldA
and
hldD
, and by performing complementation studies we confirmed that the functions encoded by both of these
B. cenocepacia
genes were needed for synthesis of a complete LPS core oligosaccharide. The LPS produced by SAL1 consisted of a short lipid A-core oligosaccharide and was devoid of O antigen. SAL1 was sensitive to the antimicrobial peptides polymyxin B, melittin, and human neutrophil peptide 1. In contrast, another
B. cenocepacia
mutant strain that produced complete lipid A-core oligosaccharide but lacked polymeric O antigen was not sensitive to polymyxin B or melittin. As determined by the rat agar bead model of lung infection, the SAL1 mutant had a survival defect in vivo since it could not be recovered from the lungs of infected rats 14 days postinfection. Together, these data show that the
B. cenocepacia
LPS inner core oligosaccharide is needed for in vitro resistance to three structurally unrelated antimicrobial peptides and for in vivo survival in a rat model of chronic lung infection.
Common and Variable Contributions of Fis Residues to High-Affinity Binding at Different DNA Sequences
Authors: Feldman-Cohen Leah S. , Shao Yongping , Meinhold Derrick , Miller Charmi , Colón Wilfredo , Osuna Robert 
Published: March 2006

ABSTRACT

Fis is a nucleoid-associated protein that interacts with poorly related DNA sequences with a high degree of specificity. A difference of more than 3 orders of magnitude in apparent

K
d

values was observed between specific (

K
d

, ∼1 to 4 nM) and nonspecific (

K
d

, ∼4 μM) DNA binding. To examine the contributions of Fis residues to the high-affinity binding at different DNA sequences, 13 alanine substitutions were generated in or near the Fis helix-turn-helix DNA binding motif, and the resulting proteins were purified. In vitro binding assays at three different Fis sites (
fis
P II,
hin
distal, and λ
attR
) revealed that R85, T87, R89, K90, and K91 played major roles in high-affinity DNA binding and that R85, T87, and K90 were consistently vital for binding to all three sites. Other residues made variable contributions to binding, depending on the binding site. N84 was required only for binding to the λ
attR
Fis site, and the role of R89 was dramatically altered by the λ
attR
DNA flanking sequence. The effects of Fis mutations on
fis
P II or
hin
distal site binding in vitro generally correlated with their abilities to mediate
fis
P repression or DNA inversion in vivo, demonstrating that the in vitro DNA-binding effects are relevant in vivo. The results suggest that while Fis is able to recognize a minimal common set of DNA sequence determinants at different binding sites, it is also equipped with a number of residues that contribute to the binding strength, some of which play variable roles.
The Tra Domain of the Lactococcal CluA Surface Protein Is a Unique Domain That Contributes to Sex Factor DNA Transfer
Authors: Stentz Régis , Gasson Mike , Shearman Claire 
Published: March 2006

ABSTRACT

CluA is a cell surface-presented protein that causes cell aggregation and is essential for a high-efficiency conjugation process in
Lactococcus lactis
. We know from previous work that in addition to promoting cell-to-cell contact, CluA is involved in sex factor DNA transfer. To define the CluA domains involved in aggregation and in transfer, we first performed random mutagenesis of the
cluA
gene using a modified mini-Tn
7
element which generated five amino acid insertions located throughout the encoded protein. Thirty independent
cluA
insertion mutants expressing modified CluA proteins at the cell surface were isolated and characterized further. The level of aggregation of each mutant was determined. The cell binding capacity of CluA was affected strongly when the protein had a mutation in its N-terminal region, which defined an aggregation domain extending from amino acid 153 to amino acid 483. Of the
cluA
mutants that still exhibited aggregation, eight showed an attenuated ability to conjugate, and six mutations were located in a 300-amino-acid C-terminal region of the protein defining a transfer domain (Tra). This result was confirmed by a phenotypic analysis of an additional five mutants obtained using site-directed mutagenesis in which charged amino acids of the Tra domain were replaced by alanine residues. Two distinct functional domains of the CluA protein were defined in this work; the first domain is involved in cell binding specificity, and the Tra domain is probably involved in the formation of the DNA transport machinery. This is the first report of a protein involved in conjugation that actively contributes to DNA transfer and mediates contact between donor and recipient strains.
Function of the N-Terminal Cap of the PAS Domain in Signaling by the Aerotaxis Receptor Aer
Authors: Watts Kylie J. , Sommer Kirsten , Fry Sheena L. , Johnson Mark S. , Taylor Barry L. 
Published: March 2006

ABSTRACT

Aer, the
Escherichia coli
receptor for behavioral responses to oxygen (aerotaxis), energy, and redox potential, contains a PAS sensory-input domain. Within the PAS superfamily, the N-terminal segment (N-cap) is poorly conserved and its role is not well understood. We investigated the role of the N-cap (residues 1 to 19) in the Aer PAS domain by missense and truncation mutagenesis. Aer-PAS N-cap truncations and an Aer-M21P substitution resulted in low cellular levels of the mutant proteins, suggesting that the N-terminal region was important for stabilizing the structure of the PAS domain. The junction of the N-cap and PAS core was critical for signaling in Aer. Mutations and truncations in the sequence encoding residues 15 to 21 introduced a range of phenotypes, including defects in FAD binding, constant tumbling motility, and an inverse response in which
E. coli
cells migrated away from oxygen concentrations to which they are normally attracted. The proximity of two N-cap regions in an Aer dimer was assessed in vivo by oxidatively cross-linking serial cysteine substitutions. Cross-linking of several cysteine replacements at 23°C was attenuated at 10°C, indicating contact was not at a stable dimer interface but required lateral mobility. We observed large multimers of Aer when we combined cross-linking of N-cap residues with a cysteine replacement that cross-links exclusively at the Aer dimer interface. This suggests that the PAS N-cap faces outwards in a dimer and that PAS-PAS contacts can occur between adjacent dimers.