bluuebunny/crossref_metadata_2025_split huggingface dataset:
TP0262 is a modulator of promoter activity of tpr Subfamily II genes of Treponema pallidum ssp. pallidum
Authors: Giacani Lorenzo , Godornes Charmie , Puray‐Chavez Maritza , Guerra‐Giraldez Cristina , Tompa Martin , Lukehart Sheila A. , Centurion‐Lara Arturo 
Published: April 2009

SummaryTranscriptional regulation in Treponema pallidum ssp. pallidum is poorly understood, primarily because this organism cannot be cultivated in vitro or genetically manipulated. We have recently shown a phase variation mechanism controlling transcription initiation of Subfamily II tpr (T. pallidumrepeat) genes (tprE, tprG and tprJ), a group of virulence factor candidates. Furthermore, the same study suggested that additional mechanisms might influence the level of transcription of these tprs. The T. pallidum genome sequence has revealed a few open reading frames with similarity to known bacterial transcription factors, including four catabolite activator protein homologues. In this work, sequences matching the Escherichia coli cAMP receptor protein (CRP) binding motif were identified in silico upstream of tprE, tprG and tprJ. Using elecrophoretic mobility shift assay and DNaseI footprinting assay, recombinant TP0262, a T. pallidum CRP homologue, was shown to bind specifically to amplicons obtained from the tpr promoters containing putative CRP binding motifs. Using a heterologous reporter system, binding of TP0262 to these promoters was shown to either increase (tprE and tprJ) or decrease (tprG) tpr promoter activity. This is the first characterization of a T. pallidum transcriptional modulator that influences tpr promoter activity.
Involvement of CD44v6 in InlB‐dependent Listeria invasion
Authors: Jung C. , Matzke A. , Niemann H. H. , Schwerk Christian , Tenenbaum Tobias , Orian‐Rousseau V. 
Published: April 2009

Summary Listeria monocytogenes, a Gram‐positive bacterium, is the causative agent for the disease called listeriosis. This pathogen utilizes host cell surface proteins such as E‐cadherin or c‐Met in order to invade eukaryotic cells. The invasion via c‐Met depends on the bacterial protein InlB that activates c‐Met phosphorylation and internalization mimicking in many regards HGF, the authentic c‐Met ligand. In this paper, we demonstrate that the activation of c‐Met induced by InlB is dependent on CD44v6, a member of the CD44 family of transmembrane glycoproteins. Inhibiting CD44v6 by means of a blocking peptide, a CD44v6 antibody or CD44v6‐specific siRNA prevents the activation of c‐Met induced by InlB. Subsequently, signalling, scattering and the entry of InlB‐coated beads into host cells are also impaired by CD44v6 blocking reagents. For the entry process, ezrin, a protein that links the CD44v6 cytoplasmic domain to the cytoskeleton, is required as well. Most importantly, this collaboration between c‐Met and CD44v6 contributes to the invasion of L. monocytogenes into target cells as demonstrated by a drastic decrease in bacterial invasion in the presence of blocking agents such as the CD44v6 peptide or antibody.
Bypass suppression analysis maps the signalling pathway within a multidomain protein: the RsbP energy stress phosphatase 2C from Bacillus subtilis
Authors: Brody Margaret S. , Stewart Valley , Price Chester W. 
Published: April 2009

SummaryThe network controlling the general stress response in Bacillus subtilis requires both the RsbP phosphatase and the RsbQ α/β hydrolase to convey signals of energy stress. RsbP contains three domains: an N‐terminal PAS, a central coiled‐coil and a C‐terminal PP2C phosphatase. We report here a genetic analysis that established the functional interactions of the domains and their relationship to RsbQ. Random mutagenesis of rsbP yielded 17 independent bypass suppressors that had activity in an rsbQ null strain background. The altered residues clustered in three regions of RsbP: the coiled‐coil and two predicted helices of the phosphatase domain. One helix (α0) is unique to a subfamily of bacterial PP2C phosphatases that possess N‐terminal sensing domains. The other (α1) is distinct from the active site in all solved PP2C structures. The phenotypes of the suppressors and directed deletions support a model in which the coiled‐coil negatively controls phosphatase activity, perhaps via the α0‐α1 helices, with RsbQ hydrolase activity and the PAS domain jointly comprising a positive sensing module that counters the coiled‐coil. We propose that the α0 helix characterizes an extended PP2C domain in many bacterial signalling proteins, and suggest it provides a means to communicate information from diverse input domains.
In vivo role of three fused corrinoid/methyl transfer proteins in Methanosarcina acetivorans
Authors: Oelgeschläger Ellen , Rother Michael 
Published: April 2009

Summary Methanosarcina acetivorans is able to use carbon monoxide (CO) as the sole source of energy for growth. Its carboxidotrophic growth is peculiar as it involves formation of acetate, formate and methylated thiols, besides methane. Under this condition three proteins homologous to both corrinoid proteins and methyltransferases (MA0859, MA4384 and MA4558) are highly abundant. To address their role in M. acetivorans, a set of single and double mutants, and the triple mutant, was constructed by deletion/disruption of the encoding genes. Phenotypic analysis of the mutants rules out an important role of the methyltransferase homologues in the CO2 reduction pathway of methanogenesis. Instead, the single and double mutants were affected to various degrees in their capacity to generate dimethylsulphide (DMS) from CO and to form methane from DMS. The triple mutant was unable to produce or metabolize DMS, and could not grow with DMS as the sole energy source, which demonstrates that MA0859, MA4384 and MA4558 are involved in, and required for, methylsulphide metabolism of M. acetivorans. Based on these findings we propose to designate MA0859, MA4384 and MA4558 as methyltransferases specific for methylsulphides, MtsD, MtsF and MtsH respectively.
DnaAcos hyperinitiates by circumventing regulatory pathways that control the frequency of initiation in Escherichia coli
Authors: Felczak Magdalena M. , Kaguni Jon M. 
Published: April 2009

SummaryMutants of dnaAcos are inviable at 30°C because DnaAcos hyperinitiates, leading to new replication forks that apparently collide from behind with stalled forks, thereby generating lethal double‐strand breaks. By comparison, an elevated level of DnaA also induces extra initiations, but lethality occurs only in strains defective in repairing double‐strand breaks. To explore the model that the chromosomal level of DnaAcos, or the increased abundance of DnaA, increases initiation frequency by, escaping or overcoming pathways that control initiation, respectively, we developed a genetic selection and identified seqA, datA, dnaN and hda, which function in pathways that either act at oriC or modulate DnaA activity. To assess each pathway's relative effectiveness, we used genetically inactivated strains, and quantified initiation frequency after elevating the level of DnaA. The results indicate that the hda‐dependent pathway has a stronger effect on initiation than pathways involving seqA and datA. Testing the model that DnaAcos overinitiates because it fails to respond to one or more regulatory mechanisms, we show that dnaAcos is unresponsive to hda and dnaN, which encodes the β clamp, and also datA, a locus proposed to titer excess DnaA. These results explain how DnaAcos hyperinitiates to interfere with viability.
Reduced lipopolysaccharide phosphorylation in Escherichia coli lowers the elevated ori/ter ratio in seqA mutants
Authors: Rotman Ella , Bratcher Preston , Kuzminov Andrei 
Published: April 2009

SummaryThe seqA defect in Escherichia coli increases the ori/ter ratio and causes chromosomal fragmentation, making seqA mutants dependent on recombinational repair (the seqA recA colethality). To understand the nature of this chromosomal fragmentation, we characterized ΔseqA mutants and isolated suppressors of the ΔseqA recA lethality. We demonstrate that our ΔseqA alleles have normal function of the downstream pgm gene and normal ratios of the major phospholipids in the membranes, but increased surface lipopolysaccharide (LPS) phosphorylation. The predominant class of ΔseqA recA suppressors disrupts the rfaQGP genes, reducing phosphorylation of the inner core region of LPS. The rfaQGP suppressors also reduce the elevated ori/ter ratio of the ΔseqA mutants but, unexpectedly, the suppressed mutants still exhibit the high levels of chromosomal fragmentation and SOS induction, characteristic of the ΔseqA mutants. We also found that colethality of rfaP with defects in the production of acidic phospholipids is suppressed by alternative initiation of chromosomal replication, suggesting that LPS phosphorylation stimulates replication initiation. The rfaQGP suppression of the seqA recA lethality provides genetic support for the surprising physical evidence that the oriC DNA forms complexes with the outer membrane.
Effects of Dextrose Plus Lactose in the Sows Diet on Subsequent Reproductive Performance and within Litter Birth Weight Variation
Authors: Van Den Brand H , Van Enckevort LCM , Van Der Hoeven EM , Kemp B 
Published: April 2009

ContentsEffects of dextrose plus lactose in sow’s feed were tested on subsequent reproductive performance and within litter birth weight variation. During the last week of gestation and lactation, sows were either fed a commercial lactation diet (Control: C), or an isocaloric diet containing 25 g/kg dextrose plus 25 g/kg lactose (Treatment: T). In the subsequent weaning‐to‐oestrus interval (WEI), all sows received the same amount of a commercial feed, but T sows were supplemented with 150 g dextrose plus 150 g lactose per day. Weight and backfat changes were recorded as well as litter characteristics during the treatment period and the subsequent parity. No significant effect of treatment was found on the subsequent reproductive performance, including the number of piglets born, although the number of live born piglets was 0.51 larger (p = 0.31) and weight of the live born piglets was 84 g higher in the T sows (p = 0.07) than in the C sows. When sows were categorized in sows with 12 or less and more than 12 total born piglets in the previous litter, treatment of sows with dextrose plus lactose resulted for the group with 12 or less piglets in a strong increase in subsequent total born piglets (13.97), whereas in the untreated sows the subsequent litter size was 11.89. In the group with more than 12 total born piglets, no effect of treatment was found (interaction between previous litter size and treatment p = 0.03). The within litter variation in birth weight in the subsequent litter was numerically lower in the T sows. We concluded that the use of dextrose and lactose during lactation and WEI seems to enhance litter size in sows with low previous litter size and seems to have the potential to reduce the within litter variation in birth weight.
Very high doses of valsartan provide renoprotection independently of blood pressure in a type 2 diabetic nephropathy rat model
Authors: TOMINAGA NAOTO , ROBERT ANNIE , IZUHARA YUKO , OHTOMO SHUICHI , DAN TAKASHI , CHIHARA KAZUO , KUROKAWA KIYOSHI , VAN YPERSELE DE STRIHOU CHARLES , MIYATA TOSHIO 
Published: April 2009

SUMMARY:Aim:  Angiotensin II type 1 receptor blockers (ARB) retard the progression of hypertensive diabetic kidney disease. Clinical evidence suggests that the dose of ARB required to correct hypertension is suboptimal for renoprotection evaluated by proteinuria. No systematic, prospective study has yet evaluated separately the effect of increasing doses of ARB on blood pressure and proteinuria.Methods:  Over a period of 8 weeks, the effect of seven constant doses of an ARB, valsartan (4–160 mg/kg per day), on blood pressure and proteinuria taken as a surrogate marker of nephropathy in a hypertensive, type 2 diabetic rat model, the spontaneously hypertensive/NIH‐corpulent rat (SHR/NDmcr‐cp), was assessed. In this spontaneously hypertensive rat strain, a genetic mutation in the leptin receptor gene is associated with hyperphagia leading to obesity with metabolic syndrome and eventually to nephropathy.Results:  No additional blood pressure lowering was observed above 120 mg/kg per day of valsartan, suggesting that a dose of 80–120 mg/kg per day had a maximal effect. Nevertheless, higher doses of valsartan further reduced proteinuria in a dose‐dependent fashion suggesting the absence of a maximal dose. Obesity, hyperglycaemia and hypercholesterolaemia were unaffected but hypertriglyceridaemia was partially corrected at various ARB doses.Conclusion:  ARB improve renoprotection at doses above those required for a maximal effect on blood pressure. The mechanism of the renoprotection obtained at high doses of ARB is yet to be elucidated.
Estimation of premorbid general fluid intelligence using traditional Chinese reading performance in Taiwanese samples
Authors: Chen Ying‐Jen , Ho Meng‐Yang , Chen Kwan‐Ju , Hsu Chia‐Fen , Ryu Shan‐Jin 
Published: April 2009

Aims:  The aims of the present study were to (i) investigate if traditional Chinese word reading ability can be used for estimating premorbid general intelligence; and (ii) to provide multiple regression equations for estimating premorbid performance on Raven's Standard Progressive Matrices (RSPM), using age, years of education and Chinese Graded Word Reading Test (CGWRT) scores as predictor variables.Methods:  Four hundred and twenty‐six healthy volunteers (201 male, 225 female), aged 16–93 years (mean ± SD, 41.92 ± 18.19 years) undertook the tests individually under supervised conditions. Seventy percent of subjects were randomly allocated to the derivation group (n = 296), and the rest to the validation group (n = 130).Results:  RSPM score was positively correlated with CGWRT score and years of education. RSPM and CGWRT scores and years of education were also inversely correlated with age, but the declining trend for RSPM performance against age was steeper than that for CGWRT performance. Separate multiple regression equations were derived for estimating RSPM scores using different combinations of age, years of education, and CGWRT score for both groups. The multiple regression coefficient of each equation ranged from 0.71 to 0.80 with the standard error of estimate between 7 and 8 RSPM points. When fitting the data of one group to the equations derived from its counterpart group, the cross‐validation multiple regression coefficients ranged from 0.71 to 0.79. There were no significant differences in the ‘predicted–obtained’ RSPM discrepancies between any equations.Conclusion:  The regression equations derived in the present study may provide a basis for estimating premorbid RSPM performance.
Assessing clinical learning outcomes: A descriptive study of nursing students in Kuwait
Authors: Al‐Kandari Fatimah , Vidal Victoria L. , Thomas Deepa 
Published: April 2009

AbstractThis study examined the perceptions of 202 nursing students, 14 faculty members, and 32 clinical instructors in the achievement of nursing students' clinical learning outcomes during their different clinical placements. The participants were involved in the bachelor of science in nursing and associate degree in nursing programs. Nine dimensions were studied using the Kuwait Clinical Learning Outcomes for Nursing Students tool. These were knowledge, nursing process, communication, student role, accountability, teaching/learning, organization, caring, and psychomotor skills. The perception of achievement of the clinical learning outcomes was 72% for the students, 77% for the faculty members, and 75% for the clinical instructors. The scores of both the faculty members and the clinical instructors for the student role were significantly higher than the scores of the students. The findings confirmed that the quality and type of clinical placement have a significant impact on the achievement of clinical learning outcomes and provide a strong base for students' development as future professionals.
Sociocultural factors influencing HIV/AIDS caregiving in Addis Ababa, Ethiopia
Authors: Aga Fekadu , Kylmä Jari , Nikkonen Merja 
Published: April 2009

AbstractThe sociocultural factors that influence care and caregiving vary from place to place, with both beneficial and harmful effects on the health of the caregivers. Therefore, this article presents the cultural and social structural factors that influence care and caregiving from the perspectives of the family caregivers of people living with HIV/AIDS in Addis Ababa, Ethiopia. Using semistructured interviews and participant observation, a purposive sample of six key participants and 12 general participants were interviewed in their home between December 2005 and January 2006. Four important sociocultural factors that influence care and caregiving have been identified: religious beliefs, economic issues, education, and social stigma and discrimination. The findings of our study underscore the importance of understanding the cultural and social structural factors that influence care and caregiving from the perspectives of family caregivers in order to provide culturally congruent care to those in need.
Burnout and productivity among Iranian nurses
Authors: Nayeri Nahid Dehghan , Negarandeh Reza , Vaismoradi Mojtaba , Ahmadi Fazlollah , Faghihzadeh Soghrat 
Published: April 2009

AbstractThe concept of burnout describes a number of destructive aspects in the health‐care system, especially in nursing. A descriptive study was carried out in order to investigate the relationship between burnout and productivity among 200 baccalaureate nurses working in educational hospitals in Tehran, Iran. Burnout and productivity questionnaires were employed and the data were analyzed by using descriptive and inferential statistics. The results showed that emotional exhaustion and depersonalization had significant negative correlations with productivity. Also, a significant positive correlation was found between personal accomplishment and productivity. Efforts to alleviate burnout among nurses should lead to an increased quality of patient care and improved quality of work life; if not, health‐care systems will pay the price for nurses' burnout through the quality of services that they offer.
Perceptions of distance education among nursing faculty members in North America
Authors: Mancuso Josephine M. 
Published: April 2009

AbstractA strategy to increase access to nursing education, train nurses for practice, and prepare future nurse educators is distance education. Faculty member shortages are cited as the main reason for not accepting qualified applicants. Faculty members are the core of nursing education. In order to address nursing faculty members' concerns regarding distance education and to assist in faculty member recruitment, retention, growth, and development in order to improve and enhance the quality of distance education, one must answer the question: What are nursing faculty members' perceptions of distance education in nursing? Utilizing a number of databases to locate research specific to this topic, this article provides an integrative review of the nursing literature to ascertain the faculty members' perspective of distance education. The research was analyzed, findings summarized, and limitations mentioned. Utilizing a brief supplementary review of the literature, the implications, recommendations, and need for future research are discussed.
Latitudinal distribution of prokaryotic picoplankton populations in the Atlantic Ocean
Authors: Schattenhofer Martha , Fuchs Bernhard M. , Amann Rudolf , Zubkov Mikhail V. , Tarran Glen A. , Pernthaler Jakob 
Published: April 2009

SummaryMembers of the prokaryotic picoplankton are the main drivers of the biogeochemical cycles over large areas of the world's oceans. In order to ascertain changes in picoplankton composition in the euphotic and twilight zones at an ocean basin scale we determined the distribution of 11 marine bacterial and archaeal phyla in three different water layers along a transect across the Atlantic Ocean from South Africa (32.9°S) to the UK (46.4°N) during boreal spring. Depth profiles down to 500 m at 65 stations were analysed by catalysed reporter deposition fluorescence in situ hybridization (CARD‐FISH) and automated epifluorescence microscopy. There was no obvious overall difference in microbial community composition between the surface water layer and the deep chlorophyll maximum (DCM) layer. There were, however, significant differences between the two photic water layers and the mesopelagic zone. SAR11 (35 ± 9%) and Prochlorococcus (12 ± 8%) together dominated the surface waters, whereas SAR11 and Crenarchaeota of the marine group I formed equal proportions of the picoplankton community below the DCM (both ∼15%). However, due to their small cell sizes Crenarchaeota contributed distinctly less to total microbial biomass than SAR11 in this mesopelagic water layer. Bacteria from the uncultured Chloroflexi‐related clade SAR202 occurred preferentially below the DCM (4–6%). Distinct latitudinal distribution patterns were found both in the photic zone and in the mesopelagic waters: in the photic zone, SAR11 was more abundant in the Northern Atlantic Ocean (up to 45%) than in the Southern Atlantic gyre (∼25%), the biomass of Prochlorococcus peaked in the tropical Atlantic Ocean, and Bacteroidetes and Gammaproteobacteria bloomed in the nutrient‐rich northern temperate waters and in the Benguela upwelling. In mesopelagic waters, higher proportions of SAR202 were present in both central gyre regions, whereas Crenarchaeota were clearly more abundant in the upwelling regions and in higher latitudes. Other phylogenetic groups such as the Planctomycetes, marine group II Euryarchaeota and the uncultured clades SAR406, SAR324 and SAR86 rarely exceeded more than 5% of relative abundance.
Trends towards increased use of the laparoscopic approach in colorectal surgery
Authors: Lengyel J. , Morrison C. , Sagar P. M. 
Published: April 2009

AbstractAim  The aim of the study was to identify the trend towards laparoscopic resection in the practice of one surgeon and to determine whether the default approach to all colorectal procedures could be by means of minimally invasive techniques with an associated low rate of conversion.Method  A prospective database of primary colorectal resections under the care of one colorectal surgeon collected between July 2003 and December 2008 was analysed to determine the trend in the use of the laparoscopic approach and the rate of conversion of an intention‐to‐treat policy for laparoscopic procedures. Patients with recurrent rectal or colonic malignancy were excluded from the study.Results  A total of 598 patients underwent elective colorectal resection of which 371 (62%) were carried out laparoscopically with a rate of conversion of 3.2%. The proportion of all colorectal resections that were undertaken laparoscopically in the first 1 year was 26% (22/85) (no conversions). This proportion rose to 100% (127/127) in the fifth year of the study of which 4.0% were converted. The introduction of more complex procedures did not have an adverse effect on the trend towards more laparoscopic resections The commencement of a laparoscopic colorectal fellowship in 2006 was associated with a marked increase in the number of laparoscopic cases.Conclusion  A conscious decision to make the laparoscopic approach the default for all colorectal resections can be achieved safely with a low conversion rate. This can be achieved within the context of training a ‘novice’ laparoscopic colorectal surgeon.