bluuebunny/crossref_metadata_2025_split huggingface dataset:
Longus, a Type IV Pilus of Enterotoxigenic
Escherichia coli
, Is Involved in Adherence to Intestinal Epithelial Cells
Authors: Mazariego-Espinosa Karina , Cruz Ariadnna , Ledesma Maria A. , Ochoa Sara A. , Xicohtencatl-Cortes Juan 
Published: March 2010

ABSTRACT

Enterotoxigenic
Escherichia coli
(ETEC) is the leading bacterial cause of diarrhea in the developing world, as well as the most common cause of traveler's diarrhea. The main hallmarks of this type of bacteria are the expression of one or more enterotoxins and fimbriae used for attachment to host intestinal cells. Longus is a pilus produced by ETEC. These bacteria grown in pleuropneumonia-like organism (PPLO) broth at 37°C and in 5% CO
2
produced longus, showing that the assembly and expression of the pili depend on growth conditions and composition of the medium. To explore the role of longus in the adherence to epithelial cells, quantitative and qualitative analyses were done, and similar levels of adherence were observed, with values of 111.44 × 10
4
CFU/ml in HT-29, 101.33 × 10
4
CFU/ml in Caco-2, and 107.11 × 10
4
CFU/ml in T84 cells. In addition, the E9034AΔ
lngA
strain showed a significant reduction in longus adherence of 32% in HT-29, 22.28% in Caco-2, and 21.68% in T84 cells compared to the wild-type strain. In experiments performed with nonintestinal cells (HeLa and HEp-2 cells), significant differences were not observed in adherence between E9034A and derivative strains. Interestingly, the E9034A and E9034AΔ
lngA
(pLngA) strains were 30 to 35% more adherent in intestinal cells than in nonintestinal cells. Twitching motility experiments were performed, showing that ETEC strains E9034A and E9034AΔ
lngA
(pLngA) had the capacity to form spreading zones while ETEC E9034AΔ
lngA
does not. In addition, our data suggest that longus from ETEC participates in the colonization of human colonic cells.
Heterogeneous
rpoS
and
rhlR
mRNA Levels and 16S rRNA/rDNA (rRNA Gene) Ratios within
Pseudomonas aeruginosa
Biofilms, Sampled by Laser Capture Microdissection
Authors: Pérez-Osorio Ailyn C. , Williamson Kerry S. , Franklin Michael J. 
Published: March 2010

ABSTRACT

The local environmental conditions in biofilms are dependent on the impinging aqueous solution, chemical diffusion, and the metabolic activities of cells within the biofilms. Chemical gradients established in biofilms lead to physiological heterogeneities in bacterial gene expression. Previously, we used laser capture microdissection (LCM) and quantitative reverse transcription (RT)-PCR to target defined biofilm subpopulations for gene expression studies. Here, we combined this approach with quantitative PCR of bacterial DNA to normalize the amount of gene expression per cell. By comparing the ratio of 16S rRNA to 16S rDNA (rRNA gene), we demonstrated that cells at the top of thick
Pseudomonas aeruginosa
biofilms have 16S rRNA/genome ratios similar to those of cells in a transition from the exponential phase to the stationary phase. Cells in the middle and bottom layers of these biofilms have ratios that are not significantly different from those of stationary-phase planktonic cultures. Since much of each biofilm appeared to be in a stationary-phase-like state, we analyzed the local amounts of the stationary-phase sigma factor
rpoS
gene and the quorum-sensing regulator
rhlR
gene per cell. Surprisingly, the amount of
rpoS
mRNA was largest at the top of the biofilms at the air-biofilm interface. Less than one
rpoS
mRNA transcript per cell was observed in the middle or base of the biofilms. The
rhlR
mRNA content was also greatest at the top of the biofilms, and there was little detectable
rhlR
expression at the middle or bottom of the biofilms. While the cell density was slightly greater at the bottom of the biofilms, expression of the quorum-sensing regulator occurred primarily at the top of the biofilms, where the cell metabolic activity was greatest, as indicated by local expression of the housekeeping gene
acpP
and by expression from a constitutive P

trc

promoter. The results indicate that in thick
P. aeruginosa
biofilms, cells in the 30 μm adjacent to the air-biofilm interface actively express genes associated with stationary phase, while cells in the interior portions do not express these genes and therefore are in a late-stationary-phase-like state and may be dormant.
Negative Regulation of Expression of the Nitrate AssimilationnirAOperon in the Heterocyst-Forming CyanobacteriumAnabaenasp. Strain PCC 7120
Authors: Frías José Enrique , Flores Enrique 
Published: March 2010

ABSTRACTIn the filamentous, heterocyst-forming cyanobacteriumAnabaenasp. strain PCC 7120, expression of the nitrate assimilationnirAoperon takes place in the absence of ammonium and the presence of nitrate or nitrite. Several positive-action proteins that are required for expression of thenirAoperon have been identified. Whereas NtcA and NtcB exert their action by direct binding to thenirAoperon promoter, CnaT acts by an as yet unknown mechanism. In the genome of this cyanobacterium, open reading frame (ORF)all0605(thenirBgene) is found between thenirA(encoding nitrite reductase) andntcBgenes. AnirBmutant was able to grow at the expense of nitrate as a nitrogen source and showed abnormally high levels ofnirAoperon mRNA both in the presence and in the absence of nitrate. This mutant showed increased nitrate reductase activity but decreased nitrite reductase activity, an imbalance that resulted in excretion of nitrite, which accumulated in the extracellular medium, when thenirBmutant was grown in the presence of nitrate. AnirAin-frame deletion mutant also showed a phenotype of increased expression of thenirAoperon in the absence of ammonium, independent of the presence of nitrate in the medium. Both NirB and NirA are therefore needed to keep low levels of expression of thenirAoperon in the absence of an inducer. Because NirB is also needed to attain high levels of nitrite reductase activity, NirA appears to be a negative element in the nitrate regulation of expression of thenirAoperon inAnabaenasp. strain PCC 7120.
Bacterial rRNA-Targeted Reverse Transcription-PCR Used To Identify Pathogens Responsible for Fever with Neutropenia
Authors: Sakaguchi Sachi , Saito Masahiro , Tsuji Hirokazu , Asahara Takashi , Takata Oto , Fujimura Junya , Nagata Satoru , Nomoto Koji , Shimizu Toshiaki 
Published: March 2010

ABSTRACT

The purpose of this study was to evaluate the clinical utility of bacterial rRNA-targeted reverse transcription-quantitative PCR (BrRNA RT-qPCR) assays for identifying the bacterial pathogens that cause fever with neutropenia in pediatric cancer patients, by comparing the bacterial detection rate of this technique with that of blood culture. One milliliter of blood was collected from pediatric patients who developed fever with neutropenia following cancer chemotherapy. BrRNA RT-qPCR was performed using 16 primer sets, each designed for a specific type of bacteria. The entire BrRNA RT-qPCR procedure took less than 5 h. Blood culture was performed at the same time, following the standard institutional procedure. Blood from 13 patients was collected during 23 febrile neutropenic episodes. Of these samples, bacteria were identified in 16 by BrRNA RT-qPCR (69.6%) and in 4 by blood culture (17.4%,
P
< 0.001). In all 4 blood culture-positive samples, BrRNA RT-qPCR detected the same type of bacteria as that identified by culture. In 9 samples, more than 4 types of bacteria were identified simultaneously by BrRNA RT-qPCR, most of which were anaerobic bacteria known to be part of the gut flora. We conclude that BrRNA RT-qPCR could be useful in the diagnosis of fever with neutropenia, given its high bacterial detection rate, short turnaround time, and the small blood sample required compared with the standard blood culture techniques. Our findings also indicate that anaerobic intestinal bacteria, which are difficult to detect by standard culture techniques, may be responsible for some cases of febrile neutropenia.
Rubella Virus Genotypes in the People's Republic of China between 1979 and 2007: a Shift in Endemic Viruses during the 2001 Rubella Epidemic
Authors: Zhu Zhen , Abernathy Emily , Cui Aili , Zhang Yan , Zhou Shujie , Zhang Zhenying , Wang Changyin , Wang Tongzhan , Ling Hua , Zhao Chunfang , Chen Yingqiong , He Jilan , Sun Li , Chen Xia , Tang Jihai , Feng Daxin , Wang Yan , Ba Zhuoma , Fan Lixia , Chen Haiyun , Pan Zhengfan , Zhan Jun , Chen Hui , Zhou Shunde , Zheng Lei , Gao Hui , Liang Yong , Dai Defang , Icenogle Joseph , Xu Wenbo 
Published: March 2010

ABSTRACT
The incidence of rubella cases in China from 1991 to 2007 was reviewed, and the nucleotide sequences from 123 rubella viruses collected during 1999 to 2007 and 4 viral sequences previously reported from 1979 to 1984 were phylogenetically analyzed. Rubella vaccination was not included in national immunization programs in China before 2007. Changes in endemic viruses were compared with incidences of rubella epidemics. The results showed that rubella epidemics occur approximately every 6 to 8 years (1993/1994, 2001, and 2007), and a shift of disease burden to susceptible young adults was observed. The Chinese rubella virus sequences were categorized into 5 of the 13 rubella virus genotypes, 1a, 1E, 1F, 2A, and 2B; cocirculations of these different genotypes were found in China. In Anhui province, a shift in the predominant genotype from 1F and 2B to 1E coincided with the 2001 rubella epidemic. This shift may have occurred throughout China during 2001 to 2007. This study investigated the genotype distribution of rubella viruses in China over a 28-year period to establish an important genetic baseline in China during its prevaccination era.
Fear of dying in an ethnically diverse society: cross-sectional studies of people aged 65+ in Britain
Authors: Bowling Ann , Iliffe Steve , Kessel Anthony , Higginson Irene J 
Published: March 2010

Abstract

Aim
To examine fears about dying in an ethnically diverse population sample, and a more homogeneous population sample, aged 65 and over.

Methods
Personal interviews with people aged 65+ living at home responding to two Office for National Statistics Omnibus Surveys in Britain, and two Ethnibus Surveys of ethnically diverse populations in Britain.

Results
Ethnically diverse respondents were more likely than British population respondents to express fears about dying on all measures used. Respondents in both samples with better, compared with worse, quality of life had significantly reduced odds of having extreme fears of dying (ethnically diverse sample, OR 0.924 (95% CI 0.898 to 0.951); British population sample, OR 0.981 (95% CI 0.966 to 0.996); both p&lt;0.001). In the latter sample only, older age was protective (OR 0.957; 95% CI 0.930 to 0.985; p&lt;0.001), whereas in the Ethnibus sample, having a longstanding illness (OR 2.024; 95% CI 1.158 to 3.535; p&lt;0.05) and having more relatives to help them (OR 1.134; 95% CI 1.010 to 1.274; p&lt;0.05) increased fears about dying.

Conclusions
Enabling older people to express fears about dying is likely to be important when planning supportive end-of-life care. Practitioners should not assume that fears about dying are the same in different social groups, or that extensive family support is protective against such anxiety. Older people from ethnic minorities had more anxieties about dying than others, and were more likely to express fears the more extensive their family support. These findings have implications for commissioners and practitioners of primary and secondary care.
Clinical and Genetic Correlates of Circulating Angiopoietin-2 and Soluble Tie-2 in the Community
Authors: Lieb Wolfgang , Zachariah Justin P. , Xanthakis Vanessa , Safa Radwan , Chen Ming-Huei , Sullivan Lisa M. , Larson Martin G. , Smith Holly M. , Yang Qiong , Mitchell Gary F. , Vita Joseph A. , Sawyer Douglas B. , Vasan Ramachandran S. 
Published: March 2010

Background—
Experimental studies suggest that endothelial growth factors play an important role in angiogenesis and vascular remodeling. The clinical and genetic correlates of circulating angiopoietin-2 (Ang-2) and its soluble receptor/regulator Tie-2 (sTie-2) have not been determined in a community-based sample.

Methods and Results—

Serum Ang-2 and sTie-2 were assayed in 3778 third-generation cohort participants of the Framingham Heart Study (mean age, 40±9 years; 53% women). Clinical correlates and heritability of both biomarkers were assessed using generalized estimating equations and variance-component analyses. Ang-2 levels were higher and sTie-2 levels were lower in women than in men. Ang-2 was positively related to age, smoking, systolic blood pressure, hypertension treatment, and diabetes (
P
<0.05 for all) but was inversely associated with total cholesterol and diastolic blood pressure (
P
<0.0001 for both), and sTie-2 was positively associated with body mass index, diabetes, and triglycerides but was inversely related to age, alcohol consumption, and glomerular filtration rate (
P
<0.05 for all). Both Ang-2 and sTie-2 were higher in participants with metabolic syndrome (
P
<0.005), with stronger associations of Ang-2 with blood pressure traits and of sTie-2 with obesity-dyslipidemia components. Heritability estimates for Ang-2 and sTie-2 were 27% and 56%, respectively (
P
<0.0001). A region on chromosome 9 was significantly linked to circulating sTie-2 levels (logarithm of the odds score, 8.31).

Conclusion—
Circulating levels of Ang-2 and sTie-2 are heritable traits associated with cardiovascular disease risk factors, including the metabolic syndrome. These observations are consistent with the notion that angiogenesis and vascular remodeling are determined in part by genetic influences and associated with metabolic risk factors.
Sea Ice Response to Atmospheric and Oceanic Forcing in the Bering Sea
Authors: Zhang Jinlun , Woodgate Rebecca , Moritz Richard 
Published: March 2010

Abstract
A coupled sea ice–ocean model is developed to quantify the sea ice response to changes in atmospheric and oceanic forcing in the Bering Sea over the period 1970–2008. The model captures much of the observed spatiotemporal variability of sea ice and sea surface temperature (SST) and the basic features of the upper-ocean circulation in the Bering Sea. Model results suggest that tides affect the spatial redistribution of ice mass by up to 0.1 m or 15% in the central-eastern Bering Sea by modifying ice motion and deformation and ocean flows. The considerable interannual variability in the pattern and strength of winter northeasterly winds leads to southwestward ice mass advection during January–May, ranging from 0.9 × 1012 m3 in 1996 to 1.8 × 1012 m3 in 1976 and averaging 1.4 × 1012 m3, which is almost twice the January–May mean total ice volume in the Bering Sea. The large-scale southward ice mass advection is constrained by warm surface waters in the south that melt 1.5 × 1012 m3 of ice in mainly the ice-edge areas during January–May, with substantial interannual variability ranging from 0.94 × 1012 m3 in 1996 to 2.0 × 1012 m3 in 1976. Ice mass advection processes also enhance thermodynamic ice growth in the northern Bering Sea by increasing areas of open water and thin ice. Ice growth during January–May is 0.90 × 1012 m3 in 1996 and 2.1 × 1012 m3 in 1976, averaging 1.3 × 1012 m3 over 1970–2008. Thus, the substantial interannual variability of the Bering Sea ice cover is dominated by changes in the wind-driven ice mass advection and the ocean thermal front at the ice edge. The observed ecological regime shifts in the Bering Sea occurred with significant changes in sea ice, surface air temperature, and SST, which in turn are correlated with the Pacific decadal oscillation over 1970–2008 but not with other climate indices: Arctic Oscillation, North Pacific index, and El Niño–Southern Oscillation. This indicates that the PDO index may most effectively explain the regime shifts in the Bering Sea.
Weak Mixing in the Eastern North Atlantic: An Application of the Tracer-Contour Inverse Method
Authors: Zika Jan D. , McDougall Trevor J. , Sloyan Bernadette M. 
Published: March 2010

Abstract
The tracer-contour inverse method is used to infer mixing and circulation in the eastern North Atlantic. Solutions for the vertical mixing coefficient D, the along-isopycnal mixing coefficient K, and a geostrophic streamfunction Ψ are all direct outputs of the method. The method predicts a vertical mixing coefficient O(10−5 m2 s−1) in the upper 1000 m of the water column, consistent with in situ observations. The method predicts a depth-dependent along-isopycnal mixing coefficient that decreases from O(1000 m2 s−1) close to the mixed layer to O(100 m2 s−1) in the interior, which is also consistent with observations and previous hypotheses. The robustness of the result is tested with a rigorous sensitivity analysis including the use of two independently constructed datasets.
This study confirms the utility of the tracer-contour inverse method. The results presented support the hypothesis that vertical mixing is small in the thermocline of the subtropical Atlantic Ocean. A strong depth dependence of the along-isopycnal mixing coefficient is also demonstrated, supporting recent parameterizations for coarse-resolution ocean models.
Oblique Femoral Tunnel Placement Can Increase Risks of Short Femoral Tunnel and Cross-Pin Protrusion in Anterior Cruciate Ligament Reconstruction
Authors: Chang Chong Bum , Yoo Jae Ho , Chung Byung June , Seong Sang Cheol , Kim Tae Kyun 
Published: March 2010

Background: A more horizontal femoral tunnel has been emphasized for contemporary anterior cruciate ligament (ACL) reconstruction. However, lowering the femoral tunnel may result in a shorter tunnel. In addition, a more horizontally placed femoral tunnel may have inadequate bone stock at the posterior portion of the tunnel, which can lead to protrusion of the cross-pin (Rigidfix) system for femoral fixation. Hypothesis: A more horizontal femoral tunnel position, particularly via the anteromedial (AM) portal technique, will reduce femoral tunnel length, and a more horizontal femoral tunnel position and anterior-to-posterior pin insertion will increase the risk of Rigidfix pin protrusion. Study Design: Controlled laboratory study. Methods: In 10 cadaveric knees, we measured maximum lengths of the femoral tunnels at the positions of 11:30, 10:30, and 9:30 o’clock using the transtibial technique and at the 10:30 and 9:30 o’clock using the AM portal technique. Then, for each femoral tunnel via the transtibial technique at 11:30, 10:30, and 9:30 o’clock positions, tests were performed for 3 directions of Rigidfix pin insertion using the lateral epicondyle as an anatomical landmark, namely, 15° anterior to posterior (A-P), neutral, and 15° posterior to anterior (P-A). It was then determined whether pins protruded from the posterior cortex. Results: The lengths of femoral tunnels produced using the transtibial technique became shorter as the femoral starting position became more horizontal (51.1 mm, 40.0 mm, and 34.2 mm on average at the 11:30, 10:30, and 9:30 o’clock position, respectively). Tunnels made using the AM portal technique were significantly shorter than those made using the transtibial technique: by 7.6 mm at the 10:30 o’clock and 4.5 mm at the 9:30 o’clock positions on average ( P < .001). In addition, increasing obliquity increased the likelihood of Rigidfix pin protrusion, especially when pins were inserted in the A-P direction. Conclusion: The current effort to lower the femoral tunnel position in ACL reconstruction can shorten the tunnel length and compromise the graft fixation at the femur using the Rigidfix system. Clinical Relevance: When an intended femoral tunnel position is more horizontal than the 10:30 o’clock position for ACL reconstruction, a surgeon needs to be cautious regarding a short femoral tunnel, particularly when using the AM portal technique, and possible protrusion of the cross-pin (Rigidfix) fixator.
Footwear Traction and Lower Extremity Joint Loading
Authors: Wannop John W. , Worobets Jay T. , Stefanyshyn Darren J. 
Published: March 2010

Background: Traction is influenced by the sole architecture and playing surface, with increases in traction potentially leading to injury. The mechanism as to how or why increased traction could lead to injury remains unknown. Purpose: This study was undertaken to determine how shoes of different sole designs and traction influence knee and ankle joint moments. Study Design: Controlled laboratory study. Methods: Traction testing was performed on 2 shoes of varying sole designs (tread vs smooth) using a robotic testing machine. All testing was conducted on a 60-cm × 90-cm piece of sample track surface. Kinematic and kinetic data were then collected on 13 recreational athletes performing running V-cuts in the 2 different shoe conditions. Five trials per condition were collected with reflective markers placed on the right shank and shoe of each participant. Kinematic and kinetic data were collected using an 8–high-speed camera system and force plate. Results: The coefficient of translational traction and the peak moment of rotation were both significantly higher in the tread shoe compared with the smooth shoe (1.00 vs 0.87 and 23.87 N·m vs 16.12 N·m, respectively). The high-traction shoe had significantly higher peak ankle external rotation moments (89.58 N·m vs 80.17 N·m), peak knee external rotation moments (36.23 N·m vs 32.02 N·m), peak knee adduction moments (224.0 N·m vs 186.8 N·m), and knee adduction angular impulse (2.10 Nms vs 1.83 Nms) compared with the low-traction shoe. Conclusion: Increased shoe traction significantly increased ankle and knee joint moments during a V-cut. Despite the significant difference in traction, no difference in performance was observed. These changes could have an effect on ankle and knee joint injury. Clinical Relevance: Shoes with decreased traction could be used in sports to reduce the joint moments in the knee and ankle and potentially reduce injury without a loss in performance.