bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lipopolysaccharide from Prevotella nigrescens stimulates osteoclastogenesis in cocultures of bone marrow mononuclear cells and primary osteoblasts
Authors: Chung Y.‐H. , Chang E.‐J. , Kim S.‐J. , Kim H.‐H. , Kim H.‐M. , Lee S.‐B. , Ko J. S. 
Published: May 2006

Background and Objective:  Lipopolysaccharide is thought to be a major virulence factor of pathogens associated with periodontal diseases and is believed to stimulate bone resorption in vivo. Although Prevotella nigrescens has been implicated in periodontitis, its role in osteoclastogenesis has not been reported. In this study, we investigated the effects of lipopolysaccharide from P. nigrescens on the formation of osteoclasts and the production of cytokines related to osteoclast differentiation.Material and Methods:  Mouse bone marrow mononuclear cells were cultured in the presence of macrophage colony‐stimulating factor (M‐CSF) and receptor activator of nuclear factor κB ligand (RANKL), with or without lipopolysaccharide. Bone marrow mononuclear cells were also cocultured with calvarial osteoblastic cells in the presence or absence of lipopolysaccharide. Osteoclast formation was determined by tartrate‐resistant acid phosphatase cytochemistry. The production of osteoprotegerin (OPG), M‐CSF, tumor necrosis factor alpha (TNF‐α), transforming growth factor‐beta (TGF‐β) and prostaglandin E2 (PGE2) was determined by enzyme‐linked immunosorbent assay (ELISA).Results:  P. nigrescens lipopolysaccharide inhibited osteoclast differentiation from bone marrow mononuclear cells cultured in the presence of M‐CSF and RANKL. However, in the coculture system, P. nigrescens lipopolysaccharide stimulated osteoclastogenesis. Notably, P. nigrescens lipopolysaccharide decreased OPG production but increased TGF‐β secretion. In addition, treatment with P. nigrescens lipopolysaccharide increased PGE2 production during the late stage of the culture period. There was no difference in M‐CSF and TNF‐α production.Conclusion:  These results demonstrate that P. nigrescens lipopolysaccharide stimulates osteoclastogenesis in the coculture system by decreasing the production of OPG and increasing the production of TGF‐β and PGE2. Through the mechanisms involving these factors, P. nigrescens lipopolysaccharide may cause alveolar bone resorption in periodontal diseases.
Hormone therapy is associated with smaller Achilles tendon diameter in active post‐menopausal women
Authors: Cook J. L. , Bass S. L. , Black J. E. 
Published: May 2006

The effects of hormonal status and activity levels on Achilles tendon structure were examined in asymptomatic post‐menopausal women. It was hypothesized that women using hormone replacement therapy (HRT) would have better tendon structure than those not using HRT and that active women would have poorer tendon structure than inactive women.Eighty‐five women including 53 active women (regular golf players) and 32 controls (healthy but inactive women) recorded their HRT and menopausal history and underwent basic anthropometric measurements. Women were divided into two groups based on their hormonal status: those currently using HRT; and those who had never used HRT or ceased using HRT at least 12 months prior to the study. Achilles tendons were examined with ultrasound and categorized as normal or abnormal, and the diameter of each tendon (mm) was recorded.Active women had a greater prevalence of tendon abnormality (P=0.10) and thicker Achilles tendons than inactive women (P<0.05). Active women on HRT had less tendon abnormality (P=0.056) than active women not on HRT and significantly less tendon thickness (P<0.05).This study indicates that Achilles tendon diameter is greater in active post‐menopausal women. Hormone replacement therapy appeared to ameliorate this effect in active women. A similar effect from HRT on the Achilles tendons of inactive women was not apparent.
Circulating Endothelial Progenitor Cells During Normal Pregnancy and Pre‐Eclampsia
Authors: Matsubara Keiichi , Abe Emiko , Matsubara Yuko , Kameda Kenji , Ito Masaharu 
Published: May 2006

ProblemEndothelial progenitor cell (EPC), which mediates neovascularization of uterine endometrium may be involved in the neovascularization in the utero‐placental circulation. We evaluated whether EPC proliferation in pre‐eclampsia (PE) differed from that in normal pregnancy.Method of studyEPC number in peripheral blood (20 non‐pregnancy, 36 normal pregnancy, 10 PE) was measured using flow cytometry. Peripheral blood mononuclear cell was cultured for 7 days and EPC proliferation was assessed based on detection of the uptake of acetylated low‐density lipoprotein and lectin. Furthermore, the proliferative activity induced by angiotensin II (Ang II) and tumor necrosis factor‐α (TNF‐α) was measured by BrdU assay.ResultsEPC number in peripheral blood did not differ significantly between PE and normal pregnancy; however, EPC proliferation was significantly increased in PE. Furthermore, Ang II and TNF‐α induced the proliferation of EPC derived from patients with PE.ConclusionsIn PE, some factors including Ang II and TNF‐α stimulated EPC proliferation; however, the impairment of EPC mobilization into systemic circulation by serum factors may contribute to insufficient regeneration of EC in disturbed utero‐placental circulation of PE.
Laughing Falcon (Herpetotheres cachinnans) Predation on Coral Snakes (Micrurus nigrocinctus)1
Authors: DuVal Emily H. , Greene Harry W. , Manno Katharina L. 
Published: May 2006

ABSTRACTLaughing falcon (Herpetotheres cachinnans) predation on coral snakes (Micrurus nigrocinctus) was recorded in two incidents that illustrate previously unreported variation in predatory behavior. In the first, the falcon held a live coral snake by the posterior end for an extended period of time, rather than decapitating it immediately. In the second, the falcon left a decapitated coral snake in a tree for more than 2 h before returning to recover its prey. A variety of behavioral adaptations may protect laughing falcons from coral snake venom.
Feeding Behavior of Purple‐throated Fruitcrow (Querula purpurata: Cotingidae) in the Colombian Amazon and Its Implications for Seed Dispersal1
Authors: Parrado‐Rosselli Angela , Amaya‐Espinel Juan David 
Published: May 2006

ABSTRACTWe studied some feeding behaviors of the purple‐throated fruitcrow (Querula purpurata) in two Colombian Amazonian forests, which affect the primary seed dispersal of the plants on which it feeds. Visit length, number of fruits removed and dispersed, feeding rates, and fruit‐handling times were compared to those obtained for two other cotingas feeding on the same fruiting trees. Querula purpurata exhibited shorter visits (98 sec) and fruit‐handling times (4 sec), and higher mean feeding rates (1.6 fruits/min) than Phoenicircus nigricollis and Cotinga cayana. In contrast, P. nigricollis dispersed the highest number of seeds of four of the five tree species studied. Although Q. purpurata and P. nigricollis exhibited feeding behaviors that increase seed dispersal, Q. purpurata may be more important in the transport of seeds between habitats, while P. nigricollis may be a major seed disperser within the primary forest.
Sesiid Moths Reduce Germination, Seedling Growth, and Survivorship in Pentaclethra macroloba (Mimosoideae), a Locally Dominant Lowland Neotropical Tree1
Authors: McKenna Duane D. , McKenna Katherine M. 
Published: May 2006

ABSTRACTMonodominant forests are a widespread feature of the humid and wet lowland tropics, but little is known about their origins or factors mediating their persistence. Nonetheless, escape from significant vertebrate and invertebrate seed predation plays a prominent role in most hypotheses. The seeds of Pentaclethra macroloba (Fabaceae: Mimosoideae) have long been thought to be virtually immune to predation, contributing to its local dominance in the canopy of some Mesoamerican forests. Here, we describe herbivory by the larvae of Carmenta surinamensis (Lepidoptera: Sesiidae) on the seeds of P. macroloba, and report the results of studies designed to clarify how this interaction influences germination, seedling growth, and mortality. To this end, we collected P. macroloba seeds at 30‐d intervals for 5 mo along a rain forest transect in Costa Rica. The seeds were monitored in a shade house for 30 d. Adult moths were reared from 43.6 percent of seeds, and significantly affected germination and mortality, and all measures of growth (number of leaves, seedling height, seed and seedling mass at 30 d, and 30‐d change in seed and seedling mass). Based on these observations, we conclude that seed boring by C. surinamensis is a potentially important factor influencing population dynamics in P. macroloba, and warrants further investigation for its prospective role in regulating local abundance in this locally dominant and ecologically significant tree.
Edaphic and Floristic Variation within a 1‐ha Plot of Lowland Amazonian Rain Forest1
Authors: Poulsen Axel Dalberg , Tuomisto Hanna , Balslev Henrik 
Published: May 2006

ABSTRACTSeveral studies in lowland tropical rain forests have documented effects of local‐scale topographic variation on plant species distribution and abundance patterns. Few studies have compared the distribution patterns of more than one plant group, however, and even fewer have related these to measured physical and chemical soil characteristics. Here, we document such soil characteristics within a square 1‐ha plot in Amazonian Ecuador, and compare them to the distribution patterns of terrestrial pteridophytes, angiosperm ground herbs, and palms. Substantial variation in soil properties was found within the plot. The three plant groups showed highly correlated floristic patterns within the 1‐ha plot even after the effect of geographical distances had been taken into account. Mantel tests yielded significant correlations between edaphic patterns, as measured by distances in various soil and topographic characteristics, and floristic patterns. For all three plant groups, differences in elevation within the plot were highly correlated with floristic distances, and for terrestrial pteridophytes and palms, distances in soil calcium content and sand content were also important. Our results resembled those obtained at wider spatial scales with the same plant groups, which indicates that soil factors may play an important role for distribution and beta diversity of plants, even at the local scale.
Eucharitid Parasitism of the Neotropical Ant Ectatomma tuberculatum: Parasitoid Co‐occurrence, Seasonal Variation, and Multiparasitism1
Authors: Pérez‐Lachaud Gabriela , López‐Méndez José Antonio , Lachaud Jean‐Paul 
Published: May 2006

ABSTRACTMultiparasitism is reported for the first time in Eucharitidae (Hymenoptera: Chalcidoidea). Dilocantha lachaudii, Isomerala coronata, and Kapala sp. were found simultaneously attacking the same population of Ectatomma tuberculatum (Olivier) (Hymenoptera: Formicidae: Ectatomminae) in southern Mexico. Adults of D. lachaudii and I. coronata completed development on the same individual host on three occasions. The genus Kapala is reported for the first time as a parasitoid of E. tuberculatum, and I. coronata is reported in Mexico for the first time.
Abundance of Gall Midges on Poulsenia armata (Moraceae): Importance of Host Plant Size and Light Environment in Tropical Rain Forests1
Authors: Castellanos I. , Cuevas‐Reyes P. , Ríos‐Casanova L. , Oyama K. , Quesada M. 
Published: May 2006

ABSTRACTWe studied the effects of contrasting light environments on the relationship between the host plant size of Poulsenia armata and the abundance of two gall midges in a tropical rain forest in Veracruz, Mexico. The number and density of two gall morphs (i.e., laminar and vein‐petiole galls) were positively correlated with plant size only in trees found in the forest but not in gaps. The availability of foliar area of P. armata trees was greater in forest gaps than in the forest. The foliar area was positively correlated with the abundance of laminar galls in trees in forest sites, but not with vein‐petiole galls. We concluded that the abundance of two morphs of gall midges on P. armata was associated with host plant size only in the forest trees. Larger plants had more galls than small plants, although this relationship was affected by local light environments.
Pilot testing of manganese oxidation in a high‐rate sedimentation process for the reprovisioning of the Sha Tin water treatment works, Hong Kong Special Administrative Region
Authors: Ko William C. G. , Mak Bevis W. L. , Pun Suki S. K. 
Published: May 2006

AbstractThe Sha Tin water treatment works (STWTW), Hong Kong Special Adminstrative Region, was commissioned in 1964 with an initial treatment capacity of 364 million litres per day (MLD). Since then it has undergone three stages of expansion to reach the current nominal capacity of 1227 MLD. The plant is in need of an in situ reprovisioning. The challenge is to complete the reprovisioning while maintaining a minimum output of 900 MLD, with any shutdown to be limited to 8 h generally. With the site already fully utilised, the key to success is to first replace the conventional low‐rate sedimentation process with high‐rate robust processes to free up the much needed space. Among other requirements, the chosen process must also be capable of treating water with variable turbidity and removing spikes of manganese effectively. The project team conducted a 4‐month pilot testing programme with an Actiflo® high‐rate pilot plant and the key results are described.
Gene Involved in Transcriptional Activation of the
hrp
Regulatory Gene
hrpG
in
Xanthomonas oryzae
pv. oryzae
Authors: Tsuge Seiji , Nakayama Takeshi , Terashima Shinsaku , Ochiai Hirokazu , Furutani Ayako , Oku Takashi , Tsuno Kazunori , Kubo Yasuyuki , Kaku Hisatoshi 
Published: May 2006

ABSTRACT

A novel regulatory gene,
trh
, which is involved in
hrp
gene expression, is identified in the plant pathogen
Xanthomonas oryzae
pv. oryzae. In the
trh
mutant, expression of HrpG, which is a key regulator for
hrp
gene expression, is reduced both under the in vitro
hrp
-inducing condition and in planta.
Anatomy of a Lactococcal Phage Tail
Authors: Mc Grath Stephen , Neve Horst , Seegers Jos F. M. L. , Eijlander Robyn , Vegge Christina S. , Brøndsted Lone , Heller Knut J. , Fitzgerald Gerald F. , Vogensen Finn K. , van Sinderen Douwe 
Published: May 2006

ABSTRACT

Bacteriophages of the
Siphoviridae
family utilize a long noncontractile tail to recognize, adsorb to, and inject DNA into their bacterial host. The tail anatomy of the archetypal
Siphoviridae
λ has been well studied, in contrast to phages infecting gram-positive bacteria. This report outlines a detailed anatomical description of a typical member of the
Siphoviridae
infecting a gram-positive bacterium. The tail superstructure of the lactococcal phage Tuc2009 was investigated using N-terminal protein sequencing, Western blotting, and immunogold transmission electron microscopy, allowing a tangible path to be followed from gene sequence through encoded protein to specific architectural structures on the Tuc2009 virion. This phage displays a striking parity with λ with respect to tail structure, which reenforced a model proposed for Tuc2009 tail architecture. Furthermore, comparisons with λ and other lactococcal phages allowed the specification of a number of genetic submodules likely to encode specific tail structures.
Crl Activates Transcription Initiation of RpoS-Regulated Genes Involved in the Multicellular Behavior ofSalmonella entericaSerovar Typhimurium
Authors: Robbe-Saule Véronique , Jaumouillé Valentin , Prévost Marie-Christine , Guadagnini Stéphanie , Talhouarne Christelle , Mathout Hayette , Kolb Annie , Norel Françoise 
Published: May 2006

ABSTRACTInSalmonella entericaserovar Typhimurium, the stationary-phase sigma factor σS(RpoS) is required for virulence, stress resistance, biofilm formation, and development of the rdar morphotype. This morphotype is a multicellular behavior characterized by expression of the adhesive extracellular matrix components cellulose and curli fimbriae. The Crl protein ofEscherichia coliinteracts with σSand activates expression of σS-regulated genes, such as thecsgBACoperon encoding the subunit of the curli proteins, by an unknown mechanism. Here, we showed using in vivo and in vitro experiments that the Crl protein ofSalmonellaserovar Typhimurium is required for development of a typical rdar morphotype and for maximal expression of thecsgD,csgB,adrA, andbcsAgenes, which are involved in curli and cellulose biosynthesis. In vitro transcription assays and potassium permanganate reactivity experiments with purified His6-Crl showed that Crl directly activated σS-dependent transcription initiation at thecsgDandadrApromoters. We observed no effect of Crl on σ70-dependent transcription. Crl protein levels increased during the late exponential and stationary growth phases in Luria-Beratani medium without NaCl at 28°C. We obtained complementation of thecrlmutation by increasing σSlevels. This suggests that Crl has a major physiological impact at low concentrations of σS.
Inhibition of ATP Hydrolysis by Thermoalkaliphilic F
1
F
o
-ATP Synthase Is Controlled by the C Terminus of the ε Subunit
Authors: Keis Stefanie , Stocker Achim , Dimroth Peter , Cook Gregory M. 
Published: May 2006

ABSTRACT

The F
1
F
o
-ATP synthases of alkaliphilic bacteria exhibit latent ATPase activity, and for the thermoalkaliphile
Bacillus
sp. strain TA2.A1, this activity is intrinsic to the F
1
moiety. To study the mechanism of ATPase inhibition, we developed a heterologous expression system in
Escherichia coli
to produce TA2F
1
complexes from this thermoalkaliphile. Like the native F
1
F
o
-ATP synthase, the recombinant TA2F
1
was blocked in ATP hydrolysis activity, and this activity was stimulated by the detergent lauryldimethylamine oxide. To determine if the C-terminal domain of the ε subunit acts as an inhibitor of ATPase activity and if an electrostatic interaction plays a role, a TA2F
1
mutant with either a truncated ε subunit [i.e., TA2F
1
(ε
ΔC
)] or substitution of basic residues in the second α-helix of ε with nonpolar alanines [i.e., TA2F
1
(ε
6A
)] was constructed. Both mutants showed ATP hydrolysis activity at low and high concentrations of ATP. Treatment of the purified F
1
F
o
-ATP synthase and TA2F
1
(ε
WT
) complex with proteases revealed that the ε subunit was resistant to proteolytic digestion. In contrast, the ε subunit of TA2F
1
(ε
6A
) was completely degraded by trypsin, indicating that the C-terminal arm was in a conformation where it was no longer protected from proteolytic digestion. In addition, ATPase activity was not further activated by protease treatment when compared to the untreated control, supporting the observation that ε was responsible for inhibition of ATPase activity. To study the effect of the alanine substitutions in the ε subunit in the entire holoenzyme, we reconstituted recombinant TA2F
1
complexes with F
1
-stripped native membranes of strain TA2.A1. The reconstituted TA2F
o
F
1
(ε
WT
) was blocked in ATP hydrolysis and exhibited low levels of ATP-driven proton pumping consistent with the F
1
F
o
-ATP synthase in native membranes. Reconstituted TA2F
o
F
1
(ε
6A
) exhibited ATPase activity that correlated with increased ATP-driven proton pumping, confirming that the ε subunit also inhibits ATPase activity of TA2F
o
F
1
.
Contribution of the PhoP-PhoQ and PmrA-PmrB Two-Component Regulatory Systems to Mg2+-Induced Gene Regulation inPseudomonas aeruginosa
Authors: McPhee Joseph B. , Bains Manjeet , Winsor Geoff , Lewenza Shawn , Kwasnicka Agnieszka , Brazas Michelle D. , Brinkman Fiona S. L. , Hancock R. E. W. 
Published: May 2006

ABSTRACTWhen grown in divalent cation-limited medium,Pseudomonas aeruginosabecomes resistant to cationic antimicrobial peptides and polymyxin B. This resistance is regulated by the PhoP-PhoQ and PmrA-PmrB two-component regulatory systems. To further characterize Mg2+regulation inP. aeruginosa, microarray transcriptional profiling was conducted to compare wild-typeP. aeruginosagrown under Mg2+-limited and Mg2+-replete conditions to isogenicphoPandpmrAmutants grown under Mg2+-limited conditions. Under Mg2+-limited conditions (0.02 mM Mg2+), approximately 3% of theP. aeruginosagenes were differentially expressed compared to the expression in bacteria grown under Mg2+-replete conditions (2 mM Mg2+). Only a modest subset of the Mg2+-regulated genes were regulated through either PhoP or PmrA. To determine which genes were directly regulated, a bioinformatic search for conserved binding motifs was combined with confirmatory reverse transcriptase PCR and gel shift promoter binding assays, and the results indicated that very few genes were directly regulated by these response regulators. It was found that in addition to the previously knownoprH-phoP-phoQoperon and thepmrHFIJKLM-ugdoperon, the PA0921 and PA1343 genes, encoding small basic proteins, were regulated by Mg2+in a PhoP-dependent manner. The number of known PmrA-regulated genes was expanded to include the PA1559-PA1560, PA4782-PA4781, andfeoABoperons, in addition to the previously known PA4773-PA4775-pmrABandpmrHFIJKLM-ugdoperons.
Proteomic Insights into Metabolic Adaptations inAlcanivorax borkumensisInduced by Alkane Utilization
Authors: Sabirova Julia S. , Ferrer Manuel , Regenhardt Daniela , Timmis Kenneth N. , Golyshin Peter N. 
Published: May 2006

ABSTRACTAlcanivorax borkumensisis a ubiquitous marine petroleum oil-degrading bacterium with an unusual physiology specialized for alkane metabolism. This “hydrocarbonoclastic” bacterium degrades an exceptionally broad range of alkane hydrocarbons but few other substrates. The proteomic analysis presented here reveals metabolic features of the hydrocarbonoclastic lifestyle. Specifically, hexadecane-grown and pyruvate-grown cells differed in the expression of 97 cytoplasmic and membrane-associated proteins whose genes appeared to be components of 46 putative operon structures. Membrane proteins up-regulated in alkane-grown cells included three enzyme systems able to convert alkanes via terminal oxidation to fatty acids, namely, enzymes encoded by the well-knownalkB1gene cluster and two new alkane hydroxylating systems, a P450 cytochrome monooxygenase and a putative flavin-binding monooxygenase, and enzymes mediating β-oxidation of fatty acids. Cytoplasmic proteins up-regulated in hexadecane-grown cells reflect a central metabolism based on a fatty acid diet, namely, enzymes of the glyoxylate bypass and of the gluconeogenesis pathway, able to provide key metabolic intermediates, like phosphoenolpyruvate, from fatty acids. They also include enzymes for synthesis of riboflavin and of unsaturated fatty acids and cardiolipin, which presumably reflect membrane restructuring required for membranes to adapt to perturbations induced by the massive influx of alkane oxidation enzymes. Ancillary functions up-regulated included the lipoprotein releasing system (Lol), presumably associated with biosurfactant release, and polyhydroxyalkanoate synthesis enzymes associated with carbon storage under conditions of carbon surfeit. The existence of three different alkane-oxidizing systems is consistent with the broad range of oil hydrocarbons degraded byA. borkumensisand its ecological success in oil-contaminated marine habitats.