bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microbial communities and interactions in the lone star tick, Amblyomma americanum
Authors: CLAY K. , KLYACHKO O. , GRINDLE N. , CIVITELLO D. , OLESKE D. , FUQUA C. 
Published: September 2008

AbstractTo quantify microbial composition and interactions, we identified prokaryotic communities in the lone star tick (Amblyomma americanum) based on 16S rRNA gene sequences and direct probing. The lone star tick is the vector of emerging diseases and host to additional symbionts of unknown activity, and is representative of other blood‐sucking arthropods. We evaluated the potential for vertical (transovarial) transmission by molecular analysis of microbial symbionts from egg and larval clutches. Direct probing of adults (N = 8 populations from the southeastern and midwestern USA, 900 ticks total) revealed three vertically transmitted symbionts: a Coxiella symbiont occurred at 100% frequency, Rickettsia species occurred in 45–61% of all ticks in every population and an Arsenophonus symbiont occurred in 0–90% of ticks per population. Arsenophonus and Rickettsia exhibited significant heterogeneity in frequency among populations. The human pathogens Ehrlichia chafeensis and Borrelia lonestari were rare in most populations. Additional microbes were detected sporadically. Most ticks (78%) were co‐infected by two or three microbes but statistical analysis indicated no significant deviation from random co‐occurrence. Our findings indicate that microbial communities within lone star ticks are diverse, and suggest that direct probing for a wider range of prokaryotes and application of quantitative polymerase chain reaction (PCR) may provide further insights into microbial interactions within disease vectors. Our results also emphasize the close phylogenetic relationship between tick symbionts and human pathogens, and consistent differences in their prevalence.
Overproduction of Escherichia coli DNA polymerase DinB (Pol IV) inhibits replication fork progression and is lethal
Authors: Uchida Kaori , Furukohri Asako , Shinozaki Yutaka , Mori Tetsuya , Ogawara Daichi , Kanaya Shigehiko , Nohmi Takehiko , Maki Hisaji , Akiyama Masahiro 
Published: August 2008

Summary Escherichia coli dinB encodes the specialized DNA polymerase DinB (Pol IV), which is induced as part of the SOS stress‐response system and functions in translesion synthesis (TLS) to relieve the replicative Pol III that is stalled at DNA lesions. As the number of DinB molecules, even in unstressed cells, is greater than that required to accomplish TLS, it is thought that dinB plays some additional physiological role. Here, we overexpressed dinB under the tightly regulable arabinose promoter and looked for a distinct phenotype. Upon induction of dinB expression, progression of the replication fork was immediately inhibited at random genomic positions, and the colony‐forming ability of the cells was reduced. Overexpression of mutated dinB alleles revealed that the structural requirements for these two inhibitory effects and for TLS were distinct. The extent of in vivo inhibition displayed by a mutant DinB matched the extent of its in vitro impedance, at near‐physiological concentration, of a moving Pol III. We suggest that DinB targets Pol III, thereby acting as a brake on replication fork progression. Because the brake operates when cells have excess DinB, as they do under stress conditions, it may serve as a checkpoint that modulates replication to safeguard genome stability.
Cytolocalization of the PhoP response regulator in Salmonella enterica: modulation by extracellular Mg2+ and by the SCV environment
Authors: Sciara Mariela I. , Spagnuolo Carla , Jares‐Erijman Elizabeth , García Véscovi Eleonora 
Published: August 2008

SummaryThe PhoP/PhoQ two‐component system plays an essential role regulating numerous virulence phenotypes in Salmonella enterica. Previous work showed that PhoQ, the sensor protein, switches between the kinase‐ and the phosphatase‐dominant state in response to environmental Mg2+ availability. This switch defines the PhoP phosphorylation status and, as a result, the transcriptional activity of this regulator. In this work, using the FlAsH labelling technique, we examine PhoP cytolocalization in response to extracellular Mg2+ limitation in vitro and to the Salmonella‐containing vacuole (SCV) environment in macrophage cells. We demonstrate that in these PhoP/PhoQ‐inducing environments PhoP displays preferential localization to one cell pole, while being homogeneously distributed in the bacterial cytoplasm in repressing conditions. Polar localization is lost in the absence of PhoQ or when a non‐phosphorylatable PhoPD52A mutant is expressed. However, when PhoP transcriptional activation is achieved in a Mg2+‐ and PhoQ‐independent manner, PhoP regains asymmetric polar localization. In addition, we show that, in the analysed conditions, PhoQ cellular distribution does not parallel PhoP location pattern. These findings reveal that PhoP cellular location is dynamic and conditioned by its environmentally defined transcriptional status, showing a new insight in the PhoP/PhoQ system mechanism.
pH and carbon supply control the expression of phosphoenolpyruvate carboxylase kinase genes in Arabidopsis thaliana
Authors: CHEN ZHI‐HUI , JENKINS GARETH I. , NIMMO HUGH G. 
Published: September 2008

ABSTRACTPhosphoenolpyruvate carboxylase (PEPC) is thought to play many roles in C3 plants including the provision of biosynthetic precursors and control of pH during N assimilation. Its activity is controlled via phosphorylation catalysed by PEPC kinases, which are encoded by PPCK genes. We examined PPCK expression in response to changes in the supply of N or C, and to changes in intracellular pH, using cultured Arabidopsis cells and seedlings. The results show that expression of both PPCK1 and PPCK2 is increased by C availability, but does not respond to N availability. Expression of the two PPCK genes and the phosphorylation state of PEPC are increased in response to increasing intracellular pH. Elevated pH also reduces the repression of PPCK gene expression by Pi. Expression of phosphoenolpyruvate carboxykinase (PEPCK), which catalyses the decarboxylation of oxaloacetate, is decreased in response to increasing intracellular pH. pH homeostasis may be mediated at least partly by reciprocal changes in the expression of PPCK genes and PEPCK.
Ethylene insensitivity impedes a subset of responses to phosphorus deficiency in tomato and petunia
Authors: KIM HYE‐JI , LYNCH JONATHAN P. , BROWN KATHLEEN M. 
Published: September 2008

ABSTRACTThe role of ethylene in growth and developmental responses to low phosphorus stress was evaluated using ethylene‐insensitive ‘Never‐ripe’ (Nr) tomato and etr1 petunia plants. Low phosphorus increased adventitious root formation in ‘Pearson’ (wild‐type) tomato plants, but not in Nr, supporting a role for ethylene in adventitious root development and showing that ethylene is important for this aspect of phosphorus response. Low phosphorus reduced ethylene production by adventitious roots of both genotypes, suggesting that ethylene perception – not production – regulates carbon allocation to adventitious roots at the expense of other roots under low phosphorus stress. With the exception of its effect on adventitious rooting, Nr had positive effects on growth and biomass accumulation in tomato whereas etr1 tended to have negative effects on petunia. This was particularly evident during the recovery from transplanting, when the effective quantum yield of photosystem II of etr1 petunia grown with low phosphorus was significantly lower than ‘Mitchell Diploid’, suggesting that etr1 petunia plants may undergo more severe post‐transplant stress at low phosphorus availability. Our results demonstrate that ethylene mediates adventitious root formation in response to phosphorus stress and plays an important role for quick recovery of plants exposed to multiple environmental stresses, i.e. transplanting and low phosphorus.
Genetic analysis of sympatric char populations in western Alaska: Arctic char (Salvelinus alpinus) and Dolly Varden (Salvelinus malma) are not two sides of the same coin
Authors: TAYLOR E. B. , LOWERY E. , LILLIESTRÅLE A. , ELZ A. , QUINN T. P. 
Published: September 2008

AbstractThe North Pacific Ocean has been of great significance to understanding biogeography and speciation in temperate faunas, including for two species of char (Salmonidae:Salvelinus) whose evolutionary relationship has been controversial. We examined the morphology and genetics (microsatellite and mitochondrial DNA) of Arctic char (Salvelinus alpinus) and Dolly Varden char (Salvelinus malma) in lake systems in western Alaska, the eastern and western Arctic, and south of the Alaskan Peninsula. Morphologically, each lake system contained two forms: one (Arctic char) largely confined to lake habitats and characterized by greater numbers of pyloric caeca, gill rakers, and shallower bodies, and another (Dolly Varden) predominated in adjacent stream habitats and was characterized by fewer pyloric caeca, gill rakers, and deeper bodies. MtDNA partial (550 bp) d‐loop sequences of both taxa were interspersed with each other within a single ‘Bering’ clade and demographic inferences suggested historical gene flow from Dolly Varden to Arctic char had occurred. By contrast, the taxa were strongly differentiated in sympatry across nine microsatellite loci in both lakes. Our data show that the two taxa are highly genetically distinct in sympatry, supporting their status as valid biological species, despite occasional hybridization. The interaction between these species highlights the importance of the North Pacific, and Beringia in particular, as an evolutionary wellspring of biodiversity.
Association of human leukocyte antigen polymorphism with outcomes of hepatitis B virus infection
Authors: Ramezani Amitis , Hasanjani Roshan Mohammad Reza , Kalantar Ebrahim , Eslamifar Ali , Banifazl Mohammad , Taeb Jaleh , Aghakhani Arezoo , Gachkar Latif , Velayati Ali Akbar 
Published: August 2008

AbstractBackground and Aim:  Host genetic and environmental factors are viewed as a common basis of the different outcomes of hepatitis B virus (HBV) infection. Human leukocyte antigen (HLA) plays an important role in immunological reaction to HBV infection. In this study, we aimed to determine the association between HBV infection and HLA‐A, B, and DRB1 alleles in northern Iran.Methods:  HLA‐A, B, and DRB1 alleles in 33 patients with chronic hepatitis B (CHB) and 31 healthy carriers as the persistent group, and 30 subjects who had spontaneously recovered from HBV infection were analyzed by using the polymerase chain reaction (PCR)–sequence‐specific primer (PCR‐SSP) technique.Results:  The frequency of the HLA‐A*33 allele was higher in the persistent group than in the recovered group (10.16% vs 0%, P < 0.008); the frequency of the DRB1*13 allele was lower in the persistent group than in the recovered group (3.13% vs 11.67%, P < 0.03). The frequency of the B*52 allele was higher in CHB patients than healthy carriers (7.58% vs 0%, P < 0.05). The logistic regression model showed that the presence of the HLA‐DRB1*13 allele was the significant factor associated with protection against the persistency of HBV. There were significant differences between the HBV recovered group, CHB patients, and healthy carriers regarding age, hepatitis B e antigen, and anti‐hepatitis B e positivity.Conclusion:  HLA‐A*33 was closely related with susceptibility to persisting hepatitis B infection, and HLA‐DRB1*13 was closely related with protection against persisting hepatitis B in an Iranian population. These findings emphasized that the host HLA polymorphism is an important factor in determining the outcome of HBV infection.
Acylated ghrelin level in patients with OSA before and after nasal CPAP treatment
Authors: TAKAHASHI Ken‐ichi , CHIN Kazuo , AKAMIZU Takashi , MORITA Satoshi , SUMI Kensuke , OGA Toru , MATSUMOTO Hisako , NIIMI Akio , TSUBOI Tomomasa , FUKUHARA Shunichi , KANGAWA Kenji , MISHIMA Michiaki 
Published: September 2008

Background and objective:  Patients with newly diagnosed OSA have been reported to have recent weight gain prior to diagnosis. Ghrelin stimulates food intake and increases weight gain. Plasma ghrelin is decreased in obese and increased in lean individuals. Of the two circulating forms of ghrelin, acylated and unacylated, the former is thought to be essential for the biological activity of ghrelin.Methods:  The plasma levels of the two forms of ghrelin were measured in 21 OSA patients (with a mean of 46.2 sleep‐disordered events/h) before and after 1 month of nasal CPAP (nCPAP) treatment, and were compared with those in 14 untreated OSA patients and 13 individuals without OSA.Results:  The BMI was significantly higher in the 21 OSA patients than in the non‐OSA group as were the baseline acylated (11.4 ± 5.86 vs 7.19 ± 3.80 fmol/mL, P = 0.03) and unacylated (84.2 ± 50.6 vs 48.3 ± 23.2 fmol/mL, P = 0.02) ghrelin levels. The total ghrelin level was positively correlated with the number of sleep‐disordered breathings (P = 0.002). After 1 month of nCPAP treatment, the acylated ghrelin level significantly decreased (P = 0.02) while the unacylated ghrelin level did not (P = 0.09).Conclusions:  Treatment of OSA may play an important role in the management of obesity in these patients by reducing the acylated ghrelin level.
Clinical characteristics and efficacy of bronchoscopic intervention for tracheobronchial leiomyoma
Authors: KWON Yong Soo , KIM Hojoong , KOH Won‐Jung , SUH Gee Young , CHUNG Man Pyo , KWON O. Jung , HAN Joungho 
Published: September 2008

Background and objective:  This study reports the clinical characteristics, efficacy and safety of bronchoscopic treatment of patients with tracheobronchial leiomyoma.Methods:  A retrospective study of 10 patients with tracheobronchial leiomyoma who underwent bronchoscopic intervention between 2000 and 2007 at a single centre, documenting the clinical characteristics, treatment method and outcomes.Results:  Seven men and three women were studied. The median age at diagnosis was 47 years (range 17–66). The most frequent symptoms were cough (n = 5) and dyspnoea (n = 4). The lesions were in the trachea in two patients, the right bronchi in six, and the left bronchi in two. On chest CT, the most frequent findings were a tracheobronchial mass without parenchymal lesion (n = 7). The tumours were removed by neodymium‐yttrium‐aluminum‐garnet laser treatment by rigid bronchoscopy under general anaesthesia (n = 9) and with flexible bronchoscopy under local (n = 1) anaesthesia. Two patients eventually underwent surgical resection because of late tumour recurrence at 16 months, after the bronchoscopic intervention, in one patient, and incomplete removal by bronchoscopic intervention in another patient. In eight of ten patients who were successfully treated by the bronchoscopic intervention, the clinical outcome was good during the median follow‐up period of 24.5 months. There were no procedure‐related mortalities or late complications.Conclusions:  Patients with a tracheobronchial leiomyoma usually present with non‐specific respiratory symptoms and an endobronchial mass without parenchymal lesions. Bronchoscopic intervention is a safe and effective technique for the treatment of patients with a tracheobronchial leiomyoma.
Predictors of long‐term survival in elderly patients hospitalized for acute exacerbations of chronic obstructive pulmonary disease
Authors: FRUCHTER Oren , YIGLA Mordechai 
Published: September 2008

Background and objective:  There is a paucity of survival data regarding the prognosis of elderly patients following acute exacerbations of COPD (AECOPD). We undertook a study to examine long‐term mortality rates and to identify clinical and laboratory predictors of these outcomes.Methods:  A retrospective cohort study was conducted of 786 consecutive elderly (>65 years) patients admitted to general medicine acute‐care wards for AECOPD. Factors determining short‐ and long‐term mortality were analysed.Results:  The mean (±SD) age of the study population was 75.8 ± 7.3 years (range 65–100 years). The in‐hospital mortality rate for the entire cohort was 7.25%. The risk of mortality at 1, 3 and 5 years was 28%, 47% and 54%, respectively. In univariate analysis age (hazard ratio 1.52; 95% confidence interval: 1.23–1.91), FEV1 (1.45; 1.73–2.35), active cancer (1.23; 1.64–2.32), current smoking (1.74; 1.35–2.11), ischaemic heart disease (1.58; 1.28–2.02), congestive heart failure (1.55; 1.23–2.26) and maintenance use of oral glucocorticosteroids (1.58; 1.11–2.79) were significantly associated with mortality. In multivariate analysis, only current smoking (1.89; 1.18–1.93), ischaemic heart disease (1.41; 1.07–1.68), PaCO2 on admission (1.49; 1.03–1.60), hospital readmission (2.23; 1.40–2.18) and FEV1 (1.41; 1.12–1.54) were independent predictors of mortality.Conclusions:  This study provides new insights into the predictive factors associated with long‐term prognosis in elderly patients admitted for acute exacerbations of COPD, which differ from those previously identified for younger patients.
Poor clinical outcomes associated with a multi‐drug resistant clonal strain of Pseudomonas aeruginosa in the Tasmanian cystic fibrosis population
Authors: BRADBURY Richard , CHAMPION Alan , REID David W. 
Published: September 2008

Background and objective:  Clonal strains of Pseudomonas aeruginosa have been identified in large cystic fibrosis (CF) centres. Whether such strains are more virulent or whether cross‐infection between patients explains their widespread prevalence is unknown. This study described the epidemiology of P. aeruginosa infection in CF patients in Tasmania, Australia, an area with a high CF birth incidence. Patients in Tasmania are geographically dispersed and when this study was conducted (2003) there was no central CF clinic, with patients receiving treatment in regional hospitals.Methods:  P. aeruginosa isolates from CF adults aged 15 years and over in Tasmania were genotyped using random amplified polymorphic DNA (RAPD)‐PCR and clonal strains confirmed with pulsed field gel electrophoresis.Results:  Airway samples were obtained from 41 patients (82% of the adult CF population). P. aeruginosa was isolated from 34 patients and nine (26%) of these individuals harboured P. aeruginosa strains with identical RAPD‐PCR and pulsed field gel electrophoresis patterns (Australian Epidemic Strain III – AES III). AES III was isolated from patients in all regions of Tasmania and was distinct from the epidemic CF strains described on mainland Australia (AES I and II). The possible link between CF adults infected with AES III was attendance at family camps more than 12 years previously. Patients harbouring AES III had suffered significantly more exacerbations requiring hospitalisation during the 2 years prior to the study compared with patients infected with unique strains (P < 0.01). AES III displayed increased multi‐antibiotic resistance compared with other strains (P < 0.001).Conclusions:  Clonal strains of P. aeruginosa may arise even in isolated CF populations. The increased exacerbation rate in patients infected with AES III and its antibiotic resistance profile strongly suggest increased virulence.
A culture‐independent study of free‐living fungi in biological soil crusts of the Colorado Plateau: their diversity and relative contribution to microbial biomass
Authors: Bates Scott T. , Garcia‐Pichel Ferran 
Published: September 2008

SummaryMolecular methodologies were used to investigate free‐living fungal communities associated with biological soil crusts (BSCs), along km‐scale transects on the Colorado Plateau (USA). Two cyanobacteria‐dominated crust types that did not contain significant lichen cover were examined. Fungal community diversity and composition were assessed with PCR‐denaturing gradient gel electrophoresis (DGGE) fingerprinting and sequencing, and fungi‐specific quantitative PCR was used to measure fungal population densities as compared with those of bacteria. Our results clearly indicate that free‐living fungi, while ubiquitous in BSCs, are less diverse and contribute far less biomass than their bacterial counterparts. Biological soil crust fungal community structure differed from that of uncrusted soils in their surroundings. Phylogenetic analyses placed the majority of BSC fungi within the Ascomycota, confirmed the importance of dematiaceous fungi, and pointed to members of the genera Alternaria and Acremonium as the most common free‐living fungi in these crusts. Phylotypes potentially representing novel taxa were recovered, as were several belonging to the Basidiomycota that would not have been readily recognized by culture‐dependant means.
Botulinum toxin type A inhibits sensory neuropeptide release in rat bladder models of acute injury and chronic inflammation
Authors: Lucioni Alvaro , Bales Gregory T. , Lotan Tamara L. , McGehee Daniel S. , Cook Sean P. , Rapp David E. 
Published: September 2008

OBJECTIVETo determine the effect of botulinum toxin type A (BTX‐A) on the release of the neuropeptides substance P (SP) and calcitonin gene‐related peptide (CGRP) from isolated bladder preparations after acute injury with HCl and the induction of cyclophosphamide (CYP)‐induced cystitis, as neurogenic inflammation has been increasingly identified in urological disorders such as interstitial cystitis.MATERIALS AND METHODSAdult rats had either an intraperitoneal injection with CYP or saline over a 10‐day period to induce chronic bladder inflammation, after which the bladder was harvested, or normal bladder explants were injured acutely with incubation (20 s) in HCl (0.4 m). To measure the effect of BTX‐A on the release of neurotransmitters, harvested bladders were incubated in an organ bath containing BTX‐A (10 U) or vehicle. Bladders were transferred to a subsequent bath (physiological saline) and incubated for 15 min, and the bathing medium analysed to measure neurotransmitter release, as determined by radioimmunoassay. Bladder specimens from sham treatment, controls and experimental rats were compared histologically.RESULTSAcute injury with HCl caused a significantly greater release of both CGRP and SP release (1235 and 1655 pg/g, respectively) than in controls (183 and 449 pg/g, respectively; P < 0.001). This increase in neurotransmitter release was partly inhibited by exposure to BTX‐A (870 and 1033 pg/g (P < 0.05 and <0.01). CYP‐induced chronic inflammation caused significantly greater release of SP than in the controls (1060 and 605 pg/g, respectively; P < 0.005). Exposure to BTX‐A partly inhibited the release of SP after CYP‐induced cystitis (709 pg/g, P < 0.05).CONCLUSIONSThe application of BTX‐A inhibits the release of sensory neurotransmitters from isolated bladder preparations in rat bladder models of both acute injury and chronic inflammation, suggesting a potential clinical benefit of BTX‐A in the treatment of neurogenic inflammation.