bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular and Biochemical Characterization of the Parvulin-Type PPIases in Lotus japonicus
Authors: Kouri Evangelia D. , Labrou Nikolaos E. , Garbis Spiros D. , Kalliampakou Katerina I. , Stedel Catalina , Dimou Maria , Udvardi Michael K. , Katinakis Panagiotis , Flemetakis Emmanouil
Published: April 2009

The cis/trans isomerization of the peptide bond preceding proline is an intrinsically slow process, although important in many biological processes in both prokaryotes and eukaryotes. In vivo, this isomerization is catalyzed by peptidyl-prolyl cis/trans-isomerases (PPIases). Here, we present the molecular and biochemical characterization of parvulin-type PPIase family members of the model legume Lotus japonicus, annotated as LjPar1, LjPar2, and LjPar3. Although LjPar1 and LjPar2 were found to be homologous to PIN1 (Protein Interacting with NIMA)-type parvulins and hPar14 from human, respectively, LjPar3 represents a novel multidomain parvulin, apparently present only in plants, that contains an active carboxyl-terminal sulfurtransferase domain. All Lotus parvulins were heterologously expressed and purified from Escherichia coli, and purified protein verification measurements used a liquid chromatography-mass spectrometry-based proteomic method. The biochemical characterization of the recombinant Lotus parvulins revealed that they possess PPIase activity toward synthetic tetrapeptides, although they exhibited different substrate specificities depending on the amino acid amino terminal to proline. These differences were also studied in a structural context using molecular modeling of the encoded polypeptides. Real-time reverse transcription-polymerase chain reaction revealed that the three parvulin genes of Lotus are ubiquitously expressed in all plant organs. LjPar1 was found to be up-regulated during the later stages of nodule development. Subcellular localization of LjPar-enhanced Yellow Fluorescence Protein (eYFP) fusions expressed in Arabidopsis (Arabidopsis thaliana) leaf epidermal cells revealed that LjPar1- and LjPar2-eYFP fusions were localized in the cytoplasm and in the nucleus, in contrast to LjPar3-eYFP, which was clearly localized in plastids. Divergent substrate specificities, expression profiles, and subcellular localization indicate that plant parvulin-type PPIases are probably involved in a wide range of biochemical and physiological processes.
Sucrose Control of Translation Mediated by an Upstream Open Reading Frame-Encoded Peptide
Authors: Rahmani Fatemeh , Hummel Maureen , Schuurmans Jolanda , Wiese-Klinkenberg Anika , Smeekens Sjef , Hanson Johannes
Published: April 2009

Regulation of gene expression through translational control is common in many organisms. The Arabidopsis (Arabidopsis thaliana) transcription factor bZIP11 is translational repressed in response to sucrose (Suc), resulting in Suc-regulated changes in amino acid metabolism. The 5′ leader of the bZIP11 mRNA harbors several upstream open reading frames (uORFs), of which the second uORF is well conserved among bZIP11 homologous genes. The uORF2 element encodes a Suc control peptide (SC-peptide) of 28 residues that is sufficient for imposing Suc-induced repression of translation (SIRT) on a heterologous mRNA. Detailed analysis of the SC-peptide suggests that it functions as an attenuator peptide. Results suggest that the SC-peptide inhibits bZIP11 translation in response to high Suc levels by stalling the ribosome on the mRNA. The conserved noncanonical AUG contexts of bZIP11 uORFs allow inefficient translational initiation of the uORF, resulting in translation initiation of the scanning ribosome at the AUG codon of the bZIP11 main ORF. The results presented show that Suc-dependent signaling mediates differential translation of mRNAs containing SC-peptides encoding uORFs.
A Versatile Zero Background T-Vector System for Gene Cloning and Functional Genomics
Authors: Chen Songbiao , Songkumarn Pattavipha , Liu Jianli , Wang Guo-Liang
Published: April 2009

With the recent availability of complete genomic sequences of many organisms, high-throughput and cost-efficient systems for gene cloning and functional analysis are in great demand. Although site-specific recombination-based cloning systems, such as Gateway cloning technology, are extremely useful for efficient transfer of DNA fragments into multiple destination vectors, the two-step cloning process is time consuming and expensive. Here, we report a zero background TA cloning system that provides simple and high-efficiency direct cloning of PCR-amplified DNA fragments with almost no self-ligation. The improved T-vector system takes advantage of the restriction enzyme XcmI to generate a T-overhang after digestion and the negative selection marker gene ccdB to eliminate the self-ligation background after transformation. We demonstrate the feasibility and flexibility of the technology by developing a set of transient and stable transformation vectors for constitutive gene expression, gene silencing, protein tagging, protein subcellular localization detection, and promoter fragment activity analysis in plants. Because the system can be easily adapted for developing specialized expression vectors for other organisms, zero background TA provides a general, cost-efficient, and high-throughput platform that complements the Gateway cloning system for gene cloning and functional genomics.
Adrenocorticotrophic hormone (ACTH) responsiveness to ghrelin increases after 6 months of ketoconazole use in patients with Cushing’s disease: comparison with GH‐releasing peptide‐6 (GHRP‐6)
Authors: Correa‐Silva Silvia R. , Nascif Sérgio O. , Molica Patrícia , Sá Larissa B. P. C. , Vieira José G. H. , Lengyel Ana‐Maria J.
Published: April 2009

Background  In Cushing’s disease (CD), adrenocorticotrophic hormone (ACTH)/cortisol responses to growth hormone secretagogues (GHS), such as ghrelin and GHRP‐6, are exaggerated. The effect of clinical treatment of hypercortisolism with ketoconazole on ACTH secretion in CD is controversial. There are no studies evaluating ACTH/cortisol responses to GHS after prolonged ketoconazole use in these patients.

Objective  To compare ghrelin‐ and GHRP‐6‐induced ACTH/cortisol release before and after ketoconazole treatment in patients with CD.

Design/patients  Eight untreated patients with CD (BMI: 28·5 ± 0·8 kg/m2) were evaluated before and after 3 and 6 months of ketoconazole treatment and compared with 11 controls (BMI: 25·0 ± 0·8).

Results  After ketoconazole use, mean urinary free cortisol values decreased significantly (before: 613·6 ± 95·2 nmol/24 h; 3rd month: 170·0 ± 27·9; 6th month: 107·9 ± 30·1). The same was observed with basal serum cortisol (before: 612·5 ± 69·0 nmol/l; 3rd month: 463·5 ± 44·1; 6th month: 402·8 ± 44·1) and ghrelin‐ and GHRP‐6‐stimulated peak cortisol levels (before: 1183·6 ± 137·9 and 1045·7 ± 132·4; 3rd month: 637·3 ± 69·0 and 767·0 ± 91·0; 6th month: 689·8 ± 74·5 and 571·1 ± 71·7 respectively). An increase in basal ACTH (before: 11·2 ± 1·6 pmol/l; 6th month: 19·4 ± 2·7) and in ghrelin‐stimulated peak ACTH values occurred after 6 months (before: 59·8 ± 15·4; 6th month: 112·0 ± 11·2). GHRP‐6‐induced ACTH release also increased (before: 60·7 ± 17·2; 6th month: 78·5 ± 12·1), although not significantly.

Conclusions  The rise in basal ACTH levels during ketoconazole treatment in CD could be because of the activation of normal corticotrophs, which were earlier suppressed by hypercortisolism. The enhanced ACTH responses to ghrelin after ketoconazole in CD could also be due to activation of the hypothalamic–pituitary–adrenal axis and/or to an increase in GHS‐receptors expression in the corticotroph adenoma, consequent to reductions in circulating glucocorticoids.
Gene expression signature of chronic lymphocytic leukaemia with Trisomy 12
Authors: Porpaczy E. , Bilban M. , Heinze G. , Gruber M. , Vanura K. , Schwarzinger I. , Stilgenbauer S. , Streubel B. , Fonatsch C. , Jaeger U.
Published: April 2009

Background  The prognosis of chronic lymphocytic leukaemia (CLL) patients is largely determined by the karyotype of the malignant clone. We have investigated the gene expression profile associated with trisomy 12 (+12).

Design  Initially, unselected peripheral blood mononuclear cells of four patients with +12 were compared with 16 CLL controls using microarray analysis. Results were validated by quantitative real‐time PCR with RNA from 61 patients (29 with +12, 32 CLL controls).

Results  Seven genes showing the strongest correlation with +12 in microarray analysis were selected for real‐time PCR: HIP1R, MYF6, SLC2A6, CD9 (overexpressed); CD200, P2RY14, RASGRP3 (underexpressed). Four genes were significantly associated with +12: HIP1R (P < 0·0001), MYF6 (P = 0·007), P2RY14 (P = 0·014), CD200 (P = 0·028). Receiver Operating Characteristic curve analysis revealed that HIP1R expression was a highly sensitive and specific marker for +12 in CLL patients. MYF6 was exclusively expressed in normal or malignant B cells in peripheral blood but was poorly predictive for +12. As expected, a number of overexpressed genes are located on chromosome 12 (HIP1R, MYF6). Interestingly, both significantly underexpressed genes (P2RY14, CD200) reside on the long arm of chromosome 3 pointing to trans‐repression in this region.

Conclusions  Analysis of the molecular signature of trisomy 12 in CLL resulted in: (i) identification of a surrogate marker for PCR (HIP1R); (ii) observation of a gene dosage effect; and (iii) detection of specific underexpression of genes located on chromosome 3. These results should help to improve diagnosis and treatment decisions for patients with CLL and trisomy 12.
Selective predation by larval Agabus (Coleoptera: Dytiscidae) on mosquitoes: support for conservation‐based mosquito suppression in constructed wetlands
Authors: CULLER LAUREN E. , LAMP WILLIAM O.
Published: April 2009

1. Wetland insect predators can structure aquatic prey communities via selective predation, but receive considerably less attention than vertebrate predators. We conducted laboratory experiments to test selective predation by two species of larval dytiscid beetles (Agabus; Coleoptera: Dytiscidae) and the potential contribution of these beetles to suppression of mosquito populations in constructed wetlands.

2. Agabus consumed copepods, ostracods and mosquito larvae in no‐choice tests. When offered a choice, 76% of all prey consumed were mosquito larvae, indicating selective predation. Subsequent experiments revealed this preference was due to ease of capture of mosquito larvae over alternative prey.

3. Cannibalism and intraguild predation were common within and between species of Agabus, which may reduce the overall impact of the observed selective predation.

4. Agabus larvae selectively preyed on mosquito larvae over alternative prey, which is not characteristic of some fish used as biological control agents for mosquitoes. Predator exclusion or similar experiments in the field could document how these results translate into a natural setting.

5. The findings of this study suggest developing mosquito suppression strategies focused on conservation of native wetland predators. These strategies are preferable to introducing non‐native generalist predators, or applying pesticides.
Interactions between Swi1‐Swi3, Mrc1 and S phase kinase, Hsk1 may regulate cellular responses to stalled replication forks in fission yeast
Authors: Shimmoto Michie , Matsumoto Seiji , Odagiri Yukari , Noguchi Eishi , Russell Paul , Masai Hisao
Published: April 2009

The Swi1‐Swi3 replication fork protection complex and Mrc1 protein are required for stabilization of stalled replication forks in fission yeast. Hsk1 kinase also plays roles in checkpoint responses elicited by arrested replication forks. We show that both Swi1 and Swi3, the abundance of which are interdependent, are required for chromatin association of Mrc1. Co‐immunoprecipitation experiments show the interactions of Swi1‐Swi3, Mrc1 and Hsk1. Mrc1 interacts with Swi3 and Hsk1 proteins through its central segment (378–879) containing a SQ/TQ cluster, and this segment is sufficient for checkpoint reaction. The SQ/TQ cluster segment (536–673) is essential but not sufficient for the interactions and for resistance to replication inhibitor hydroxyurea. Mrc1 protein level is increased in hsk1–89 cells due to apparent stabilization, and we have identified a potential phosphodegron sequence. These results suggest that interactions of the Swi1‐Swi3 complex and Hsk1 kinase with Mrc1 may play a role in cellular responses to stalled replication forks in fission yeast.
Molecular mechanisms regulating dissociation of cell–cell junction of epithelial cells by oxidative stress
Authors: Inumaru Junko , Nagano Osamu , Takahashi Eri , Ishimoto Takatsugu , Nakamura Satoshi , Suzuki Yoshimi , Niwa Shin‐ichiro , Umezawa Kazuo , Tanihara Hidenobu , Saya Hideyuki
Published: April 2009

Oxidative stress is regarded as a causative factor in aging and various degenerative diseases. Here, we show the mechanism by which oxidative stress induces disruption of cell–cell junctions using retinal pigment epithelial cells. We demonstrated that reactive oxygen species (ROS)‐mediated activation of Src kinase increases the tyrosine phosphorylation state of p120‐catenin and rapidly triggers translocation of p120‐catenin and internalization of N‐cadherin from the cell–cell adhesion sites to an early endosomal compartment. Endosomal accumulation of p120‐catenin resulted in stress fiber formation and cell–cell dissociation through the activation of Rho/Rho kinase pathway. However, these cytoskeletal remodeling and cell–cell dissociation induced by oxidative stress were transient, due to the activation of nuclear factor‐κB (NF‐κB) and the expression of manganese superoxide dismutase (Mn‐SOD). Using the NF‐κB specific inhibitor DHMEQ, we found that NF‐κB is part of a negative feedback loop to control intracellular ROS levels. Finally, we demonstrated that H2O2 treatment alone does not induce the epithelial mesenchymal transition (EMT) in retinal pigment epithelial cells, which can be induced by TNF‐α treatment. These findings suggest that oxidative stress is a crucial factor to induce the cell–cell dissociation, an initial step of EMT, but does not provide sufficient signals to establish and to maintain the EMT.
Interpretation of regional aeromagnetic data by the scaling function method: the case of Southern Apennines (Italy)
Authors: Florio G. , Fedi M. , Rapolla A.
Published: April 2009

A complex aeromagnetic anomaly in Southern Apennines (Italy) is analysed and interpreted by a multiscale method based on the scaling function. We use multiscale methods allowing analysis of a potential field along ridges, which are lines defined by the position of the extrema of the field at the considered scales. The method developed and applied in this paper is based on the study of the scaling function of the total magnetic field. It allows recovering of source parameters such as depth and structural index. The studied area includes a Pleistocene volcanic structure (Mt. Vulture) whose intense dipolar anomaly is superimposed on a longer wavelength regional anomaly. The interpretation of ridges of the modulus of the analytic signal at different altitude ranges allows recognition of at least three distinct sources between about 5 km and 20 km depth. Their interpretation is discussed in light of borehole data and other geophysical constraints. A reasonable geological model for these sources indicates the presence of intrusions, probably linked to the past activity of Mt. Vulture.
Tradeoffs and thresholds in the effects of nitrogen addition on biodiversity and ecosystem functioning: evidence from inner Mongolia Grasslands
Authors: BAI YONGFEI , WU JIANGUO , CLARK CHRISTOPHER M. , NAEEM SHAHID , PAN QINGMIN , HUANG JIANHUI , ZHANG LIXIA , HAN XINGGUO
Published: April 2009

Nitrogen (N) deposition is widely considered an environmental problem that leads to biodiversity loss and reduced ecosystem resilience; but, N fertilization has also been used as a management tool for enhancing primary production and ground cover, thereby promoting the restoration of degraded lands. However, empirical evaluation of these contrasting impacts is lacking. We tested the dual effects of N enrichment on biodiversity and ecosystem functioning at different organizational levels (i.e., plant species, functional groups, and community) by adding N at 0, 1.75, 5.25, 10.5, 17.5, and 28.0 g N m−2 yr−1 for four years in two contrasting field sites in Inner Mongolia: an undisturbed mature grassland and a nearby degraded grassland of the same type. N addition had both quantitatively and qualitatively different effects on the two communities. In the mature community, N addition led to a large reduction in species richness, accompanied by increased dominance of early successional annuals and loss of perennial grasses and forbs at all N input rates. In the degraded community, however, N addition increased the productivity and dominance of perennial rhizomatous grasses, with only a slight reduction in species richness and no significant change in annual abundance. The mature grassland was much more sensitive to N‐induced changes in community structure, likely as a result of higher soil moisture accentuating limitation by N alone. Our findings suggest that the critical threshold for N‐induced species loss to mature Eurasian grasslands is below 1.75 g N m−2 yr−1, and that changes in aboveground biomass, species richness, and plant functional group composition to both mature and degraded ecosystems saturate at N addition rates of approximately 10.5 g N m−2 yr−1. This work highlights the tradeoffs that exist in assessing the total impact of N deposition on ecosystem function.
Species–area functions revisited
Authors: Williams Matthew R. , Lamont Byron B. , Henstridge John D.
Published: April 2009

Aim Numerous functions have been proposed to describe the species–area relationship but despite almost a century of curve‐fitting there is little agreement on which is best. We aimed to rationalize the list of proposed functions and to discuss appropriate methodology for fitting and comparing the alternatives.

Location Data from the British Isles were used for model comparisons.

Methods Sixteen functions that have been proposed as models of the species–area relationship were compared algebraically and reformulated into a consistent format. Each was parameterized to enable their use as link functions to model the combined effects of area and other factors (covariates) onS(species number). Using data on the number of plant species on 41 British islands, we examined the effects of ignoring important covariates on the choice of the best‐fitting function. The methods used in some recent studies that compared alternative functions were examined.

Results Many of the 16 species–area functions are special cases of others, some are identical, and two arose as a result of transcription errors. The 16 functions were reduced to a set of nine general functions. The empirical comparison showed that including covariates in addition to area resulted in a different best‐fitting function, and that different functions identified different covariates as important. Previous studies that have compared alternative functions suffered from three shortcomings: (1) too much emphasis was placed on maximizing goodness‐of‐fit betweenSandA(area), ignoring the effects of other factors, (2) most made implicit or untested assumptions about the distribution ofS, and (3) some repeated the mispractice of usingR2to compare models with different numbers of parameters or differing error distributions.

Main conclusions The generalized linear model is a framework with which to fit alternative species–area functions, and the information‐theoretic approach provides one suitable method with which to compare their fit. Ignoring the effects of important covariates may result in an incorrect choice of the best‐fitting function. The choice of function may also affect which covariates are found to be important. Determining an appropriate statistical model with which to relate species number to area and other covariates requires careful consideration of many issues, not just of the functional relationship between species number and area.
Transplacental exchange of moxidectin after maternal or fetal intravenous administration in sheep
Authors: PÉREZ R. , PALMA C. , NÚÑEZ M. J. , NAVAS M. , OLMOS G. , COX J.
Published: April 2009

The transplacental exchange of moxidectin after maternal or fetal intravenous (i.v.) administration was studied using the chronically catheterized fetal sheep model. Nine pregnant Suffolk Down sheep of 65.7 ± 5.9 kg body weight (bw) were surgically prepared to insert polyvinyl catheters in the fetal femoral artery and vein and amniotic sac. The ewes were randomly assigned to two experimental groups. In group 1 (maternal injection) five ewes were treated with an i.v. bolus of 0.2 mg of moxidectin/kg bw. In group 2, (fetal injection) an i.v. bolus of 1 mg of moxidectin was administered to the four fetuses by femoral vein catheters. Maternal and fetal blood and amniotic fluid samples were taken before and after moxidectin administration for a 144 h post‐treatment period. Samples were analyzed by liquid chromatography. A noncompartmental pharmacokinetic analysis was performed and statistical differences were determined by mean of parametric and nonparametric statistical tests. Pharmacokinetic differences observed in maternal variables were shorter elimination half‐life and mean residence time compared with values previously reported for ivermectin. Drug diffusion from maternal to fetal circulation (AUC0–t = 232.6 ± 72.5 ng·h/mL) was statistically not different (P = 0.09) compared with fetal to maternal diffusion (AUC0–t= 158.0 ± 21.6 ng·h/mL). Fetuses showed significantly (P = 0.008) lower drug body clearance values compared with those observed in the maternal side. Considering the observed transplacental passages between materno‐fetal or feto‐maternal circulations, we conclude that the placental barrier is not effective in preventing the moxidectin diffusion between mother and fetus.
Nuclear sequences reveal mid‐range isolation of an imperilled deep‐water coral population
Authors: EYTAN RON I. , HAYES MARSHALL , ARBOUR‐REILY PATRICIA , MILLER MARGARET , HELLBERG MICHAEL E.
Published: April 2009

The mitochondrial DNA of corals and their anthozoan kin evolves slowly, with substitution rates about two orders of magnitude lower than in typical bilateral animals. This has impeded the delineation of closely related species and isolated populations in corals, compounding problems caused by high morphological plasticity. Here we characterize rates of divergence and levels of variation for three nuclear gene regions, then use these nuclear sequences as markers to test for population structure inOculina, a taxonomically confused genus of corals. Rates of sequence divergence (obtained by comparison toSolenastrea hyades) were at least five (and sometimes over 10) times faster for the three nuclear markers than for a mitochondrial reference sequence. Nuclear sequence variation was also high within populations, although it tended to decline north of Cape Canaveral. Significant subdivision was evident among samples from 10 locations from between North Carolina and the Florida Panhandle, but neither nominal species designation nor population depth explained much of this variation. Instead, a single population from the unique deep (> 70 m) water reefs at the Oculina Banks off central Florida was a strong genetic outlier: all pairwise measures of subdivision involving this population were greater than those involving all other populations, and multilocus clustering recognized the Oculina Banks as distinct from other populations, despite its close proximity (≤ 36 km) to populations from shallower waters nearby and its location at the centre of the sampled range. Genetic isolation of the Oculina Banks population suggests that focused efforts will be needed to conserve the foundation species of these monotypic reefs and that depth may play a role in isolating marine populations and perhaps facilitating initial steps towards speciation.
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

Transcriptional 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

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

The 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

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

Mutants 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

The 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.
Substance P activates a non‐selective cation channel in murine pacemaker ICC
Authors: D’antonio C. , Wang B. , Mckay C. , Huizinga J. D.
Published: April 2009

Abstract Interstitial cells of Cajal (ICC) associated with Auerbach’s plexus in the small intestine, provide pacemaker activity to orchestrate peristalsis and mixing. Despite the close apposition between ICC and enteric nerves, little is known about the neural regulation of pacemaker activity. The present study pursues the hypothesis that substance P can affect pacemaker activity through action on non‐selective cation channels. Cell‐attached and inside‐out patch clamp studies were performed on isolated ICC in short‐term cultures that provided evidence that substance P increases open probability or initiates activity in non‐selective cation channels in ICC. The single‐channel conductance is ∼25 pS and in the on‐cell configuration the activity can occur in a rhythmic fashion. Patches contained 1–10 channels and were most often accompanied by a ∼12 pS chloride channel that was also activated by substance P. In a recently developed preparation that allows patch clamping in ICC in their natural environment within tissue, i.e.in situ, the presence of the channel and substance P activation was confirmed. The non‐selective cation channel is one of the channels that initiate intestinal pacemaker activity and the present study provides further single‐channel data on this critical channel. Because of the close proximity of enteric motor and sensory nerves to ICC, these data provide a potential mechanism underlying neural regulation of pacemaker activity. The data also indicate that neurokinergic pharmacology is a promising avenue for excitation of the intestinal pacemaker system.
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

Contents

Effects 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.
An autopsied case of panencephalopathic‐type Creutzfeldt‐Jakob disease with mutation in the prion protein gene at codon 232 and type 1 prion protein
Authors: Hama Tetsuo , Iwasaki Yasushi , Niwa Hisayoshi , Yoshida Mari , Hashizume Yoshio , Kitamoto Tetsuyuki , Murakami Nobuyuki , Sobue Gen
Published: April 2009

In this study, we describe the clinicopathologic findings in a 68‐year‐old man with panencephalopathic‐type CJD with a substitution from methionine to arginine at codon 232 (M232R) in the prion protein (PrP) gene and type 1 PrP. Initial symptoms of the patient were a rapidly progressive memory disturbance and disorientation. The patient showed myoclonus and periodic sharp‐wave complexes on electroencephalogram in the early stages of disease. Diffusion‐weighted MRI along with the presence of both neuron‐specific enolase and 14‐3‐3 protein in the CSF showed similarities to classic‐type sporadic CJD. The patient reached the akinetic mutism state 2 months following the onset of symptoms and died after 13 months. Neuropathologic examination revealed panencephalopathic‐type CJD pathology including widespread neuron loss with severe hypertrophic astrocytosis and status spongiosus in the cerebral gray matter, particularly in the neocortex. Cerebral white matter and the cerebellum also showed severe involvement. Immunohistochemical staining for PrP showed diffuse gray matter staining, indicating synaptic‐type PrP deposition without plaque‐type. Two different clinical phenotypes of M232R CJD were recognized despite the presence of the same PrP genotype, and the present case is speculated to correspond to the rapid‐type.
Localization of blood proteins thrombospondin1 and ADAMTS13 to cerebral corpora amylacea
Authors: Meng He , Zhang Xiaojie , Blaivas Mila , Wang Michael M.
Published: April 2009

Corpora amylacea (CA) have long been described in aging brains and in patients with neurodegenerative conditions, but their origins have been debated. It has been proposed that CA represent collections of nervous system breakdown products that accumulate within astrocytic cytoplasm. In support of this, studies have shown that CA include glycosylated material, ubiquitin, and an assortment of proteins derived from neuronal cytoplasm. On the other hand, many of these proteins are not specifically localized to neurons or astrocytes; some components of CA, such as complement proteins, are most abundantly expressed outside the central nervous system. The characteristic predilection for CA to accumulate near vessels and ependyma suggests that proteins extravasated from blood or transudated from CSF may form a component of these structures. In this study, we report the immunohistochemical localization of blood and platelet proteins thrombospondin1 and ADAMTS13 in CA from aged individuals and patients with vascular dementia. Thrombospondin1 localized to neurons, but was most prominently localized to CA. An independent serum and platelet expressed protein, ADAMTS13, was found in CA in the same brain regions. In vitro analysis shows that thrombospondin1 and ADAMTS13 form complexes together in cells and in direct protein binding assays. We speculate that CA could result from a conglomeration of interacting proteins from degenerating neurons and from extravasated blood elements released after transient breakdown of the blood–brain barrier.
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

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

This 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

The 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

The 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.