bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular defects of the glycine 41 variants of alanine glyoxylate aminotransferase associated with primary hyperoxaluria type I
Authors: Cellini Barbara , Montioli Riccardo , Paiardini Alessandro , Lorenzetto Antonio , Maset Fabio , Bellini Tiziana , Oppici Elisa , Voltattorni Carla Borri 
Published: February 2010

G41 is an interfacial residue located within the α-helix 34–42 of alanine:glyoxylate aminotransferase (AGT). Its mutations on the major (AGT-Ma) or the minor (AGT-Mi) allele give rise to the variants G41R-Ma, G41R-Mi, and G41V-Ma causing hyperoxaluria type 1. Impairment of dimerization in these variants has been suggested to be responsible for immunoreactivity deficiency, intraperoxisomal aggregation, and sensitivity to proteasomal degradation. However, no experimental evidence supports this view. Here we report that G41 mutations, besides increasing the dimer-monomer equilibrium dissociation constant, affect the protein conformation and stability, and perturb its active site. As compared to AGT-Ma or AGT-Mi, G41 variants display different near-UV CD and intrinsic emission fluorescence spectra, larger exposure of hydrophobic surfaces, sensitivity to Met53-Tyr54 peptide bond cleavage by proteinase
K
, decreased thermostability, reduced coenzyme binding affinity, and catalytic efficiency. Additionally, unlike AGT-Ma and AGT-Mi, G41 variants under physiological conditions form insoluble inactive high-order aggregates (∼5,000 nm) through intermolecular electrostatic interactions. A comparative molecular dynamics study of the putative structures of AGT-Mi and G41R-Mi predicts that G41 → R mutation causes a partial unwinding of the 34–42 α-helix and a displacement of the first 44 N-terminal residues including the active site loop 24–32. These simulations help us to envisage the possible structural basis of AGT dysfunction associated with G41 mutations. The detailed insight into how G41 mutations act on the structure-function of AGT may contribute to achieve the ultimate goal of correcting the effects of these mutations.
Plasmonic nanorod absorbers as orientation sensors
Authors: Chang Wei-Shun , Ha Ji Won , Slaughter Liane S. , Link Stephan 
Published: February 2010

Nanoparticles are actively exploited as biological imaging probes. Of particular interest are gold nanoparticles because of their nonblinking and nonbleaching absorption and scattering properties that arise from the excitation of surface plasmons. Nanoparticles with anisotropic shapes furthermore provide information about the probe orientation and its environment. Here we show how the orientation of single gold nanorods (25 × 73 nm) can be determined from both the transverse and longitudinal surface plasmon resonance by using polarization-sensitive photothermal imaging. By measuring the orientation of the same nanorods separately using scanning electron microscopy, we verified the high accuracy of this plasmon-absorption-based technique. However, care had to be taken when exciting the transverse plasmon absorption using a large numerical aperture objective as out-of-plane plasmon oscillations were also excited then. For the size regime studied here, being able to establish the nanorod orientation from the transverse mode is unique to photothermal imaging and almost impossible with conventional dark-field scattering spectroscopy. This is important because the transverse surface plasmon resonance is mostly insensitive to the medium refractive index and nanorod aspect ratio allowing nanorods of any length to be used as orientation sensors without changing the laser frequency.
Identification of an unconventional E3 binding surface on the UbcH5 ∼ Ub conjugate recognized by a pathogenic bacterial E3 ligase.
Authors: Levin Itay , Eakin Catherine , Blanc Marie-Pierre , Klevit Rachel E. , Miller Samuel I. , Brzovic Peter S. 
Published: February 2010

Gram-negative bacteria deliver a cadre of virulence factors directly into the cytoplasm of eukaryotic host cells to promote pathogenesis and/or commensalism. Recently, families of virulence proteins have been recognized that function as E3 Ubiquitin-ligases. How these bacterial ligases integrate into the ubiquitin (Ub) signaling pathways of the host and how they differ functionally from endogenous eukaryotic E3s is not known. Here we show that the bacterial E3 SspH2 from
S. typhimurium
selectively binds the human UbcH5 ∼ Ub conjugate recognizing regions of both UbcH5 and Ub subunits. The surface of the E2 UbcH5 involved in this interaction differs substantially from that defined for other E2/E3 complexes involving eukaryotic E3-ligases. In vitro, SspH2 directs the synthesis of K48-linked poly-Ub chains, suggesting that cellular protein targets of SspH2-catalyzed Ub transfer are destined for proteasomal destruction. Unexpectedly, we found that intermediates in SspH2-directed reactions are activated poly-Ub chains directly tethered to the UbcH5 active site (UbcH5 ∼ Ub

n

). Rapid generation of UbcH5 ∼ Ub

n

may allow for bacterially directed modification of eukaryotic target proteins with a completed poly-Ub chain, efficiently tagging host targets for destruction.
Effects of Forward Sales on Spot Markets: Pre‐commitment Sales and Prices for Fresh Strawberries
Authors: Mohapatra Sandeep , Goodhue Rachael E. , Carter Colin A. , Chalfant James A. 
Published: February 2010

AbstractIncreasingly, agricultural markets are vertically coordinated. Often a thinning spot market coexists with coordinated transactions, raising the question of how private coordination affects the market as a whole. One of the greatest challenges when analyzing such market‐level effects is obtaining information on private transactions. We utilize publicly available data to evaluate how informal contracts in the fresh strawberry market affect spot market prices using a generalized autoregressive conditional heteroskedastic in mean (GARCH‐M) model. We find that these informal contracts increased spot prices, as argued by some industry members, while the effect on spot price volatility varied by production region.
Silent ships sometimes do encounter more fish. 1. Vessel comparisons during winter pollock surveys
Authors: De Robertis Alex , Wilson Christopher D. , Williamson Neal J. , Guttormsen Michael A. , Stienessen Sarah 
Published: February 2010

Abstract
De Robertis, A., Wilson, C. D., Williamson, N. J., Guttormsen, M. A., and Stienessen, S. 2010. Silent ships sometimes do encounter more fish. 1. Vessel comparisons during winter pollock surveys. – ICES Journal of Marine Science, 67: 985–995. Avoidance of approaching vessels by fish is a major source of uncertainty in surveys of fish stocks. In an effort to minimize vessel avoidance, international standards for underwater-noise emission by research vessels have been established. Despite widespread investment in noise-reduced vessels, the effectiveness of noise reduction on vessel avoidance remains poorly understood. Here, we report on vessel comparisons of pollock abundance recorded by the NOAA ships “Oscar Dyson” (OD), a noise-reduced vessel, and “Miller Freeman” (MF), a conventionally designed vessel. The comparisons were made during three acoustic surveys of prespawning aggregations of walleye pollock (Theragra chalcogramma) in Alaska. The experiments demonstrate that a noise-reduced vessel will detect significantly more fish backscatter than a conventional vessel in some situations. OD detected 31% more pollock backscatter than MF in the Shumagin Islands, where pollock were distributed between 100 and 200 m deep, and 13% more pollock backscatter in Shelikof Strait, where pollock were primarily distributed 200–300 m deep. However, there was no difference in the Bogoslof Island area where pollock were found at 400–700 m. In the Shumagin and Shelikof areas, the discrepancy between vessels tended to decrease with fish depth, consistent with a decreasing response to a stimulus propagating from the surface. Analysis of the depth distributions of pollock supports the conclusion that the discrepancies in backscatter stem from differential behavioural responses to the two vessels.
Endosymbiotic associations within protists
Authors: Nowack Eva C. M. , Melkonian Michael 
Published: February 2010

The establishment of an endosymbiotic relationship typically seems to be driven through complementation of the host's limited metabolic capabilities by the biochemical versatility of the endosymbiont. The most significant examples of endosymbiosis are represented by the endosymbiotic acquisition of plastids and mitochondria, introducing photosynthesis and respiration to eukaryotes. However, there are numerous other endosymbioses that evolved more recently and repeatedly across the tree of life. Recent advances in genome sequencing technology have led to a better understanding of the physiological basis of many endosymbiotic associations. This review focuses on endosymbionts in protists (unicellular eukaryotes). Selected examples illustrate the incorporation of various new biochemical functions, such as photosynthesis, nitrogen fixation and recycling, and methanogenesis, into protist hosts by prokaryotic endosymbionts. Furthermore, photosynthetic eukaryotic endosymbionts display a great diversity of modes of integration into different protist hosts.In conclusion, endosymbiosis seems to represent a general evolutionary strategy of protists to acquire novel biochemical functions and is thus an important source of genetic innovation.
Opiate‐induced oesophageal dysmotility
Authors: KRAICHELY R. E. , ARORA A. S. , MURRAY J. A. 
Published: February 2010

Aliment Pharmacol Ther 31, 601–606SummaryBackground Opiates have well characterized (troublesome) untoward effects on the gastrointestinal tract. Opioid bowel dysfunction has been a subject of research and even drug design, but surprisingly little is known with regard to clinical effects of opiates on the oesophagus.Aim To characterize opiate effects on motor function of the oesophagus in patients presenting with dysphagia.Methods Retrospective review of 15 patients with dysphagia referred for oesophageal manometry while on chronic opiates. Manometry was completed during opiate use and in three cases, after opiates were discontinued.Results All patients demonstrated motility abnormalities. Incomplete lower oesophageal sphincter (LOS) relaxation (11.5 ± 1.6 mmHg) was seen in most cases. Ten patients demonstrated nonperistaltic contractions in ≥3 of 10 swallows. Additional abnormalities included high amplitude contractions; triple peaked contractions; and increased velocity. The average resting lower oesophageal sphincter (LOSP) met criteria for hypertensive LOS in three patients. These features were suggestive of spasm or achalasia. Repeat manometry off opiates was performed in three cases. LOS relaxation was noted to be complete upon repeat manometry in these cases. There was also improved peristalsis and normal velocity.Conclusions A range of manometric abnormalities were seen in patients with dysphagia in the setting of opiate use: impaired LOS relaxation, high amplitude/velocity and simultaneous oesophageal waves. These data suggest that the oesophagus is susceptible to the effects of opiates and care must be taken before ascribing dysphagia to a primary oesophageal motility disorder in patients taking opiates.
Predicting the advent of ascites and other complications in primary biliary cirrhosis: a staged model approach
Authors: CHAN C.‐W. , TSOCHATZIS E. A. , CARPENTER J. R. , RIGAMONTI C. , GUNSAR F. , BURROUGHS A. K. 
Published: February 2010

Aliment Pharmacol Ther 31, 573–582SummaryBackground  Current survival models for primary biliary cirrhosis have limited precision for medium and long‐term survival.Aim  To describe a prognostic model for the advent of complications in primary biliary cirrhosis as the first approach to a staged prognostic model.Methods  From an established database of 289 consecutive primary biliary cirrhosis patients referred to Royal Free Hospital over 12 years (mean follow‐up of 4.1 years), baseline characteristics at referral were evaluated by Cox‐proportional hazards regression modelling.Results  The following complications occurred de novo: 85 ascites/peripheral oedema, 40 oesophagogastric varices, 63 encephalopathy, 29 spontaneous bacterial peritonitis and/or septicaemia, 59 symptomatic urinary tract infections. Age, albumin, log10(bilirubin), presence of ascites at referral, variceal bleeding within 6 weeks before referral, detection of oesophagogastric varices at or before referral were significant at multivariate analysis with different combinations and coefficients for each complication. The model for predicting ascites and/or peripheral oedema best fitted the observed data (ROC = 0.7682, S.E. = 0.0385).Conclusions  The known prognostic factors in primary biliary cirrhosis also model the advent of complications. In view of the prognostic importance of ascites and its more robust statistical model, ascites and/or peripheral oedema could represent, following validation, the most suitable staged model in primary biliary cirrhosis to improve precision in survival modelling.
Role of ants in structuring the aphid community on apple
Authors: MIÑARRO MARCOS , FERNÁNDEZ‐MATA GABRIELA , MEDINA PILAR 
Published: February 2010

1. The aphids Dysaphis plantaginea Passerini, Aphis spp. (Aphis pomi De Geer and Aphis spiraecola Patch), and Eriosoma lanigerum Hausmann are commonly found together in apple orchards. Ants establish a mutualistic relationship with the myrmecophilous aphids D. plantaginea and Aphis spp. but not with E. lanigerum.2. Field surveys and one experiment manipulating the presence of ants and the aphid species were conducted to test the hypothesis that ants play a role in structuring the community of these aphids on apple.3. Ants tended D. plantaginea and Aphis spp. but not E. lanigerum colonies. In the field, D. plantaginea performed better in the presence of ants while no effect was observed in Aphis spp. Contrarily, populations of Aphis spp. in the manipulative experiment performed better in the presence of ants while no differences were observed for D. plantaginea. Such differences between field and manipulative conditions could be related to thermal tolerance, phenology, and life cycles. In contrast, populations of E. lanigerum were reduced in the presence of ants.4. Ants also had a significant negative effect on the abundance of natural enemies, which could partially explain the benefits to the tended aphids. However, while ants did not provide a benefit to Aphis spp. when it was reared alone, in the presence of other species ant attendance increased Aphis abundance by 256% and simultaneously reduced E. lanigerum abundance by 63%. Therefore, ants benefited Aphis by reducing competition with other aphid species, which involves a different mechanism, explaining the benefit of ant attendance. Considering all the aphid species together, ants had a net positive effect on aphid abundance, which was consequently considered harmful for the plant.5. Our results highlighted the role that ants play in structuring apple aphid communities and give support to the observed pattern that ants can benefit tended aphids while simultaneously reducing the abundance of untended herbivores.
Disruption of chemoreceptor signalling arrays by high levels of CheW, the receptor–kinase coupling protein
Authors: Cardozo Marcos J. , Massazza Diego A. , Parkinson John S. , Studdert Claudia A. 
Published: February 2010

SummaryDuring chemotactic signalling by Escherichia coli, the small cytoplasmic CheW protein couples the histidine kinase CheA to chemoreceptor control. Although essential for assembly and operation of receptor signalling complexes, CheW in stoichiometric excess disrupts chemotactic behaviour. To explore the mechanism of the CheW excess effect, we measured the physiological consequences of high cellular levels of wild‐type CheW and of several CheW variants with reduced or enhanced binding affinities for receptor molecules. We found that high levels of CheW interfered with trimer assembly, prevented CheA activation, blocked cluster formation, disrupted chemotactic ability and elevated receptor methylation levels. The severity of these effects paralleled the receptor‐binding affinities of the CheW variants. Because trimer formation may be an obligate step in the assembly of ternary signalling complexes and higher‐order receptor arrays, we suggest that all CheW excess effects stem from disruption of trimer assembly. We propose that the CheW‐binding sites in receptor dimers overlap their trimer contact sites and that high levels of CheW saturate the receptor‐binding sites, preventing trimer assembly. The CheW‐trapped receptor dimers seem to be improved substrates for methyltransferase reactions, but cannot activate CheA or assemble into clusters, processes that are essential for chemotactic signalling.
Examination of the interaction between FtsZ and MinCN in E. coli suggests how MinC disrupts Z rings
Authors: Shen Bang , Lutkenhaus Joe 
Published: February 2010

SummaryIn Escherichia coli the Min system prevents Z ring assembly at cell poles by topologically regulating the division inhibitor MinC. The MinC protein has two domains of equal size and both domains can target FtsZ and block cell division in the proper context. Recently, we have shown that, along with MinD, the C‐terminal domain of MinC (MinCC) competes with FtsA, and to a lesser extent with ZipA, for interaction with the C‐terminal tail of FtsZ to block division. Here we explored the interaction between the N‐terminal domain of MinC (MinCN) and FtsZ. A search for mutations in ftsZ that confer resistance to MinCN identified an α‐helix at the interface of FtsZ subunits as being critical for the activity of MinCN. Focusing on one such mutant FtsZ–N280D, we showed that it greatly reduced the FtsZ–MinC interaction and was resistant to MinCN both in vivo and in vitro. With these results, an updated model for the action of MinC on FtsZ is proposed: MinC interacts with FtsZ to disrupt two interactions, FtsZ–FtsA/ZipA and FtsZ–FtsZ, both of which are essential for Z ring formation.
Laparoscopic artificial urinary sphincter implantation for female genuine stress urinary incontinence: technique and 4‐year experience in 25 patients
Authors: Mandron Eric , Bryckaert Pierre‐Emmannuel , Papatsoris Athanasios G. 
Published: February 2010

Study Type – Therapy (outcomes research) Level of Evidence 2cOBJECTIVETo assess the safety, feasibility and efficacy of laparoscopic implantation of the artificial urinary sphincter (AUS) in women with genuine stress urinary incontinence (SUI).PATIENTS AND METHODSFrom April 2005 to July 2009, 25 women (mean age 66.8 years) with genuine SUI had a laparoscopic implantation of the AUS (AMS 800TM, American Medical Systems, Minnetonka, MN, USA). Patients had a negative Marshall test and urodynamic studies showed decreased closure pressure. All patients had a history of urogynaecological surgery. Transperitoneal laparoscopic access was created with two midline 10‐mm and two lateral 5‐mm trocars. One of the lateral port incisions was later extended to facilitate urethrovaginal dissection with scissors and dissector, and the insertion and assembly of the AUS. In six cases of concomitant genito‐urinary prolapse, laparoscopic anterior and posterior mesh promontofixation was also performed.RESULTSThe AUS was successfully implanted in all cases with no conversion to open surgery. There were no intra‐ or perioperative complications, except one vaginal perforation which was repaired during surgery. The mean operative duration was 92 min (71 min without and 123 min with simultaneous promontofixation). Five patients developed urinary retention, which was managed with re‐insertion of the urethral catheter for 2 days in four and with insertion of a suprapubic catheter for 4 weeks in a patient with spina bifida. During the mean follow‐up of 26.1 months, two treatment failures were diagnosed due to vaginal erosion and were managed with removal of the AUS. All the remaining 23 patients reported continence, either complete (in 19) or social (in four). However, this was not a randomized comparative study.CONCLUSIONLaparoscopic implantation of the AUS in women with genuine SUI is safe, feasible and efficient.
Comparison of the prognostic importance of diagnosed diabetes, co‐morbidity and frailty in older people
Authors: Hubbard R. E. , Andrew M. K. , Fallah N. , Rockwood K. 
Published: February 2010

Diabet. Med. 27, 603–606 (2010)AbstractAims  To compare the relative prognostic importance in older people of diagnosed diabetes, the number and severity of co‐morbidities and frailty.Methods  Two thousand three hundred and five people aged ≥ 70 years comprised the clinical examination cohort of the Canadian Study of Health and Aging. Frailty was defined as a score of ≥ 5 on a 7‐point Clinical Frailty Scale. The cohort was followed for 5 years.Results  Diabetes was more likely to be associated with medium‐term mortality (adjusted hazard ratio (HR) 1.42; 95% confidence interval (CI) 1.20–1.69) than co‐morbidity (HR 1.03; 95% CI 1.01–1.05). Frailty most strongly predicted death (HR 2.72; 95% CI 2.34–3.16). Frail older adults were 2.62 times (95% CI 1.36–5.06) more likely to have a complication of diabetes, independent of age, sex and number of years living with diabetes. People with diabetes were younger than those without (81.3 vs. 83.3 years) but a similar proportion were frail (42.2 vs.43.4%). The median life expectancy for frail older adults with diabetes was 23 months (95% CI 18–28 months).Conclusions  In this cohort, the risk of mortality in older people was defined more precisely by a clinical measure of frailty than by diabetes or burden of co‐morbidity. Those with diagnosed diabetes were younger than those without but had the same frailty status; diabetes can therefore be considered to increase ‘biological age’ by 2 years in those aged over 70 years. The limited life expectancy of frail older people with diabetes highlights the importance of recognizing frailty and supports the individualization of care in older people with diabetes.
Maternal and neonatal outcomes and time trends of gestational diabetes mellitus in Sweden from 1991 to 2003
Authors: Fadl H. E. , Östlund I. K. M. , Magnuson A. F. K. , Hanson U. S. B. 
Published: February 2010

Diabet. Med. 27, 436–441 (2010)AbstractAims  To determine maternal and neonatal outcomes for women with gestational diabetes mellitus (GDM) in Sweden during 1991–2003, and to compare the outcomes in the two time periods.Methods  This is a population‐based cohort study using the Swedish Medical Birth Register data for the period 1991–2003. There were 1 260 297 women with singleton pregnancies registered during this time, of whom 10 525 were diagnosed with GDM, based on a 75 g oral glucose tolerance test. The main diagnostic criteria were fasting capillary whole blood glucose ≥ 6.1 mmol/l and 2 h blood glucose ≥ 9.0 mmol/l.Results  Maternal characteristics differed significantly between the GDM and non‐GDM group. Adjusted odds ratios (OR) were as follows: for pre‐eclampsia, 1.81 (95% confidence interval (CI) 1.64–2.00); for shoulder dystocia, 2.74 (2.04–3.68); and for Caesarean section, 1.46 (1.38–1.54). No difference was seen in perinatal mortality, stillbirth rates, Apgar scores, fetal distress or transient tachypnoea. There was a markedly higher risk of large for gestational age, OR 3.43 (3.21–3.67), and Erb’s palsy, OR 2.56 (1.96–3.32), in the GDM group, and statistically significant differences in prematurity < 37 weeks, birth weight > 4.5 kg, and major malformation, OR 1.19–1.71. No statistically significant improvement in outcomes was seen between the two study periods.Conclusions  Women with GDM have higher risks of pre‐eclampsia, shoulder dystocia and Caesarean section. Their infants are often large for gestational age and have higher risks of prematurity, Erb’s palsy and major malformations. These outcomes did not improve over time.