bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel structural features in two ZHX homeodomains derived from a systematic study of single and multiple domains
Authors: Bird Louise E , Ren Jingshan , Nettleship Joanne E , Folkers Gert E , Owens Raymond J , Stammers David K 
Published: May 2010

Abstract

Background

Zhx 1 to 3 (zinc-fingers and homeoboxes) form a set of paralogous genes encoding multi-domain proteins. ZHX proteins consist of two zinc fingers followed by five homeodomains. ZHXs have biological roles in cell cycle control by acting as co-repressors of the transcriptional regulator Nuclear Factor Y. As part of a structural genomics project we have expressed single and multi-domain fragments of the different human ZHX genes for use in structure determination.

Results
A total of 30 single and multiple domain ZHX1-3 constructs selected from bioinformatics protocols were screened for soluble expression in E. coli using high throughput methodologies. Two homeodomains were crystallized leading to structures for ZHX1 HD4 and ZHX2 HD2. ZHX1 HD4, although closest matched to homeodomains from 'homez' and 'engrailed', showed structural differences, notably an additional C-terminal helix (helix V) which wrapped over helix I thereby making extensive contacts. Although ZHX2 HD2-3 was successfully expressed and purified, proteolysis occurred during crystallization yielding crystals of just HD2. The structure of ZHX2 HD2 showed an unusual open conformation with helix I undergoing 'domain-swapping' to form a homodimer.

Conclusions
Although multiple-domain constructs of ZHX1 selected by bioinformatics studies could be expressed solubly, only single homeodomains yielded crystals. The crystal structure of ZHX1 HD4 showed additional hydrophobic interactions relative to many known homeodomains via extensive contacts formed by the novel C-terminal helix V with, in particular, helix I. Additionally, the replacement of some charged covariant residues (which are commonly observed to form salt bridges in non-homeotherms such as the Drosophila 'engrailed' homeodomain), by apolar residues further increases hydrophobic contacts within ZHX1 HD4, and potentially stability, relative to engrailed homeodomain. ZHX1 HD4 helix V points away from the normally observed DNA major groove binding site on homeodomains and thus would not obstruct the putative binding of nucleic acid. In contrast, for ZHX2 HD2 the observed altered conformation involving rearrangement of helix I, relative to the canonical homeodomain fold, disrupts the normal DNA binding site, although protein-protein binding is possible as observed in homodimer formation.
Study of bone remodeling of two models of femoral cementless stems by means of DEXA and finite elements
Authors: Gracia Luis , Ibarz Elena , Puértolas Sergio , Cegoñino José , López-Prats Fernando , Panisello Juan J , Herrera Antonio 
Published: May 2010

AbstractBackgroundA hip replacement with a cemented or cementless femoral stem produces an effect on the bone called adaptive remodelling, attributable to mechanical and biological factors. All of the cementless prostheses designs try to achieve an optimal load transfer in order to avoid stress-shielding, which produces an osteopenia.Long-term densitometric studies taken after implanting ABG-I and ABG-II stems confirm that the changes made to the design and alloy of the ABG-II stem help produce less proximal atrophy of the femur. The simulation with FE allowed us to study the biomechanical behaviour of two stems. The aim of this study was, if possible, to correlate the biological and mechanical findings.MethodsBoth models with prostheses ABG-I and II have been simulated in five different moments of time which coincide with the DEXA measurements: postoperative, 6 months, 1, 3 and 5 years, in addition to the healthy femur as the initial reference. For the complete comparative analysis of both stems, all of the possible combinations of bone mass (group I and group II of pacients in two controlled studies for ABG-I and II stems, respectively), prosthetic geometry (ABG-I and ABG-II) and stem material (Wrought Titanium or TMZF) were simulated.Results and DiscussionIn both groups of bone mass an increase of stress in the area of the cancellous bone is produced, which coincides with the end of the HA coating, as a consequence of the bottleneck effect which is produced in the transmission of loads, and corresponds to Gruen zones 2 and 6, where no osteopenia can be seen in contrast to zones 1 and 7.ConclusionsIn this study it is shown that the ABG-II stem is more effective than the ABG-I given that it generates higher tensional values on the bone, due to which proximal bone atrophy diminishes. This biomechanical behaviour with an improved transmission of loads confirmed by means of FE simulation corresponds to the biological findings obtained with Dual-Energy X-Ray Absorptiometry (DEXA).
Optical tomographic imaging discriminates between disease-modifying anti-rheumatic drug (DMARD) and non-DMARD efficacy in collagen antibody-induced arthritis
Authors: Peterson Jeffrey D , LaBranche Timothy P , Vasquez Kristine O , Kossodo Sylvie , Melton Michele , Rader Randall , Listello John T , Abrams Mark A , Misko Thomas P 
Published: May 2010

Abstract
Introduction
Standard measurements used to assess murine models of rheumatoid arthritis, notably paw thickness and clinical score, do not align well with certain aspects of disease severity as assessed by histopathology. We tested the hypothesis that non-invasive optical tomographic imaging of molecular biomarkers of inflammation and bone turnover would provide a superior quantitative readout and would discriminate between a disease-modifying anti-rheumatic drug (DMARD) and a non-DMARD treatment.

Methods
Using two protease-activated near-infrared fluorescence imaging agents to detect inflammation-associated cathepsin and matrix metalloprotease activity, and a third agent to detect bone turnover, we quantified fluorescence in paws of mice with collagen antibody-induced arthritis. Fluorescence molecular tomographic (FMT) imaging results, which provided deep tissue detection and quantitative readouts in absolute picomoles of agent fluorescence per paw, were compared with paw swelling, clinical scores, a panel of plasma biomarkers, and histopathology to discriminate between steroid (prednisolone), DMARD (p38 mitogen-activated protein kinase (MAPK) inhibitor) and non-DMARD (celecoxib, cyclooxygenase-2 (COX-2) inhibitor) treatments.

Results
Paw thickness, clinical score, and plasma biomarkers failed to discriminate well between a p38 MAPK inhibitor and a COX-2 inhibitor. In contrast, FMT quantification using near-infrared agents to detect protease activity or bone resorption yielded a clear discrimination between the different classes of therapeutics. FMT results agreed well with inflammation scores, and both imaging and histopathology provided clearer discrimination between treatments as compared with paw swelling, clinical score, and serum biomarker readouts.

Conclusions
Non-invasive optical tomographic imaging offers a unique approach to monitoring disease pathogenesis and correlates with histopathology assessment of joint inflammation and bone resorption. The specific use of optical tomography allowed accurate three-dimensional imaging, quantitation in picomoles rather than intensity or relative fluorescence, and, for the first time, showed that non-invasive imaging assessment can predict the pathologist's histology inflammation scoring and discriminate DMARD from non-DMARD activity.
Lizards respond to an extremely low-frequency electromagnetic field
Authors: Nishimura Tsutomu , Okano Hideyuki , Tada Harue , Nishimura Etsuko , Sugimoto Kenji , Mohri Kaneo , Fukushima Masanori 
Published: May 2010

SUMMARY
Animals from a wide range of taxa have been shown to possess magnetic sense and use magnetic compasses to orient; however, there is no information in the literature on whether lizards have either of these abilities. In this study, we investigated the behavioral responses of a diurnal agamid lizard (Pogona vitticeps) to a sinusoidal extremely low-frequency electromagnetic field (ELF-EMF; 6 and 8 Hz, peak magnetic field 2.6 μT, peak electric field 10 V m−1). Fourteen adult lizards were divided randomly into two groups (the EMF and control groups; each group had three males and four females). The EMF group received whole-body exposure to ELF-EMF and the control group did not. Lizards in the EMF group were exposed to ELF-EMF for 12 h per day (during the light period). The number of tail lifts was monitored beginning 3 days before exposure and ending after 5 days of exposure. For each individual, the average number of tail lifts per day was calculated. The average number of tail lifts per individual per day was greater in the EMF group than in the control group (20.7±6.3 and 9.1±4.5 tail lifts, respectively, N=7 each, P=0.02). We confirmed the reproducibility of this response by a cross-over trial. These results suggest that at least some lizards are able to perceive ELF-EMFs. Furthermore, when the parietal eye of the lizards was covered with a small round aluminum ‘cap’ which could block light, the tail-lifting response to ELF-EMF disappeared. Our experiments suggest that (1) lizards perceive EMFs and (2) the parietal eye may be involved in light-dependent magnetoreceptive responses.
Carotenoid-based coloration, oxidative stress and corticosterone in common lizards
Authors: Cote J. , Meylan S. , Clobert J. , Voituron Y. 
Published: May 2010

SUMMARY
Environmental factors including stressors, health status and social context significantly affect carotenoid-based coloration. For instance, stressors may induce the diversion of carotenoids from pigmentation pathways, potentially explaining why stressed animals often exhibit reduced coloration. However, we recently showed that high blood corticosterone concentrations, which are part of the physiological stress response, are associated with increased redness of the belly in the common lizard (Lacerta vivipara). This result clearly contrasts with the findings of many studies of carotenoid-based coloration because corticosterone is believed to increase oxidative stress. Here, we examined whether these positive effects are influenced by differences in food availability. We tested the effect of high corticosterone levels on carotenoid-based coloration, antioxidant enzyme activity and oxidative damage in common lizards subject to low and high food availability. Food restriction abolished the carotenoid-based color enhancement when corticosterone concentrations in animals were high. We discuss how carotenoid-based color can honestly signal individual quality in this species and how the increased redness induced by corticosterone could be a terminal investment in an environment where long-term survival prospects are poor but not when immediate survival is endangered.
A sky polarization compass in lizards: the central role of the parietal eye
Authors: Beltrami G. , Bertolucci C. , Parretta A. , Petrucci F. , Foà A. 
Published: May 2010

SUMMARYThe present study first examined whether ruin lizards Podarcis sicula are able to orientate using the e-vector direction of polarized light. Ruin lizards were trained and tested indoors, inside a hexagonal Morris water maze, positioned under an artificial light source producing plane polarized light with a single e-vector, which provided an axial cue. Lizards were subjected to axial training by positioning two identical goals in contact with the centre of two opposite side walls of the Morris water maze. Goals were invisible because they were placed just beneath the water surface, and water was rendered opaque. The results showed that the directional choices of lizards meeting learning criteria were bimodally distributed along the training axis, and that after 90 deg rotation of the e-vector direction of polarized light the lizards directional choices rotated correspondingly, producing a bimodal distribution which was perpendicular to the training axis. The present results confirm in ruin lizards results previously obtained in other lizard species showing that these reptiles can use the e-vector direction of polarized light in the form of a sky polarization compass. The second step of the study aimed at answering the still open question of whether functioning of a sky polarization compass would be mediated by the lizard parietal eye. To test this, ruin lizards meeting learning criteria were tested inside the Morris water maze under polarized light after their parietal eyes were painted black. Lizards with black-painted parietal eyes were completely disoriented. Thus, the present data show for the first time that the parietal eye plays a central role in mediating the functioning of a putative sky polarization compass of lizards.
Osmoregulation in the Antarctic nematodePanagrolaimus davidi
Authors: Wharton David A. 
Published: May 2010

SUMMARYA technique for determining the internal osmotic concentration of a small nematode using a modified nanolitre osmometer is described and used to investigate osmoregulation in the Antarctic nematode Panagrolaimus davidi. This technique enables the osmotic concentration to the measured with an accuracy of ±12 mmol kg−1. The pattern of melting in the nematode's different body compartments suggests that it is the osmolality of its pseudocoelomic fluid that is being measured. Panagrolaimus davidi maintains its internal osmotic concentration above that of the external medium and is thus an hyperosmotic regulator. The nematode achieves regulation under hyposmotic stress more rapidly than under hyperosmotic stress.
Methamphetamine enhances memory of operantly conditioned respiratory behavior in the snailLymnaea stagnalis
Authors: Kennedy Colin D. , Houmes Stephen W. , Wyrick Katherine L. , Kammerzell Samuel M. , Lukowiak Ken , Sorg Barbara A. 
Published: May 2010

SUMMARYAmphetamines have been used as cognitive enhancers to promote learning and memory. Amphetamines are also drugs of abuse that may promote the initiation of strong memories that ultimately lead to addiction. To understand how methamphetamine (Meth) may be augmenting learning and memory, we chose a relatively simple system, the pond snail, Lymnaea stagnalis. We studied the effects of Meth exposure on the long-term memory (LTM), extinction and reinstatement of operantly conditioned aerial respiratory behavior in Lymnaea. We first determined doses of Meth that would acutely alter respiratory behavior. Next, we measured the impact of training snails in Meth solution or water (control group) using a training procedure that produces LTM (&gt;6 h) in control conditions. Meth exposure impaired the expression of LTM 21 h after two training sessions, but this appeared to be a context-dependent effect only. However, snails exposed to 3.3 μmol l−1 Meth during training had a decreased rate of extinction of the operantly conditioned memory. We then tested whether this decreased ability of snails to extinguish memory was due to enhanced LTM or impaired extinction of that memory. Snails were operantly conditioned in water and exposed to Meth 16 h after their last trial but 4–5 h prior to extinction. Meth produced an increase rather than a decrease in extinction rate. Thus, Meth impaired extinction only when snails were exposed to Meth during training. Last, we tested the effect of Meth on the ability to form LTM using a single training procedure that is suboptimal for LTM formation. Control snails did not demonstrate LTM, as expected, but pre-exposure of snails to 3.3 μmol l−1 Meth 24 h prior to the single training session produced LTM 24 h later, indicating that Meth pre-exposure primed snails for LTM formation. Taken together, our studies suggest that LTM is strengthened by Meth such that extinction training is less effective. Lymnaea provides a simple and useful model system to dissect the cellular and/or molecular mechanisms of how Meth may initiate the formation of stronger memories.
Effect of anomalous pulse timing on call discrimination by females of the gray treefrog (Hyla versicolor): behavioral correlates of neurobiology
Authors: Schwartz Joshua J. , Huth Kenneth , Hunce Raymond , Lentine Brandon 
Published: May 2010

SUMMARY
Research has demonstrated that certain midbrain neurons of anurans ‘count’ interpulse intervals (IPIs). Some neurons fire after exposure to fewer intervals than do others. Counting can be reset to zero if an IPI falls outside the cell's tolerance range. We tested female gray treefrogs for behavioral correlates of these neural response patterns using phonotaxis tests in order to gain a better understanding of the mechanistic bases of female responses to calls. For example, previous work demonstrated females often prefer longer to shorter pulsed advertisement calls, even when the former occur at lower rates. Call attractiveness can also be reduced when pulse duration and timing have been manipulated experimentally or disrupted by acoustic interference. In this study, female responses were consistent with neural data, emphasizing the importance of IPIs. Females discriminated in favor of calls with normal interpulse timing relative to those in which a single IPI was too long or too short. Our data suggest that neural resetting of interval counting by inappropriate intervals may more strongly influence females than reduced firing in response to such intervals on an individual basis. Data also suggest a transition point between 125 ms and 175 ms at which an interval between pulse strings is treated as an interval between calls.
Synthesis and Properties of 2,2′-Di(heteroaryl)-9,9′-spirobifluorenes
Authors: Jahng Yurngdong , Rahman A F M Motiur 
Published: May 2010

Abstract
A series of 2,2′-di(heteroaryl)-9,9′-spirobifluorenes were prepared by employing Friedländer reaction of 2,2′-diacetyl-9,9′-spirodifluorene with a series of ortho-aminoarenecarbaldehydes. The compound 2,2′-di(benzo[b]-1,10-phenanthrolin-2-yl)-9,9′-spirofluorene (4e) showed a green light emission at 500 nm upon the excitation of the absorption at 374 nm while 2,2′-di(benzo[h]quinolin-2-yl)-9,9′-spirofluorene (4c), 2,2′-di(1,10-phenanthrolin-2-yl)-9,9′-spirofluorene (4d), 2-(benzo[h]quinolin-2-yl)-2′-(benzo[b]-1,10-phenanthrolin-2-yl)-9,9′-spirofluorene (4g), and 2-(1,10-phenanthrolin-2-yl)-2′-(benzo[b]-1,10-phenanthrolin-2-yl)-9,9′-spirofluorene (4h) showed emissions at 413, 465, 442, and 442 nm upon excitation of the absorption at 370, 362, 370, and 363 nm, respectively, thus having potential for OLED applications.
Role of Substrate Reactivity in the Glutathione Peroxidase (GPx) Activity of Selenocystine
Authors: Singh Beena G , Bag Partha P , Kumakura Fumio , Iwaoka Michio , Priyadarsini K Indira 
Published: May 2010

Abstract
Selenocystine (CysSeSeCys), a diselenide, exhibits glutathione peroxidase (GPx) activity, where it catalyses the reduction of hydroperoxides using a thiol co-factor. To understand the relative reactivity of the two substrates, enzyme kinetic parameters, i.e., the turnover number (kcat) and the relative reactivity parameters toward thiol (φG) and hydroperoxide (φH), were determined by applying Dalziel kinetics for a bi-substrate model in the presence of hydrogen peroxide (H2O2), t-butyl hydroperoxide, or α-cumyl hydroperoxide and glutathione or dithiothreitol (DTTred). The intermediates formed during the reaction of CysSeSeCys with H2O2 and DTTred were characterized by 77Se NMR spectroscopy. Ab initio calculation at HF/6-31G(d) indicated that the reactions with H2O2 are exothermic, while those with DTTred are endothermic. Based on these studies, the GPx activity of CysSeSeCys is likely to be initiated by the reaction with hydroperoxide and in the catalytic cycle, the reaction with thiol is the rate-determining step.
X-ray Crystallography of D149 Ethyl Ester
Authors: Matsui Masaki , Fujita Tomoki , Kubota Yasuhiro , Funabiki Kazumasa , Miura Hidetoshi , Shiro Motoo 
Published: May 2010

Abstract
D149 ethyl ester molecules are arranged in a “herringbone” fashion. Cyclopentane, phenylene, and one of the phenyl moieties surround a planar π-conjugated chromophore to weaken π–π stacking between the molecules arranged in parallel.
Reduction of Volume Shrinkage in Holographic Polymer Dispersed Liquid Crystal Based on Epoxy Containing Polymer Matrices
Authors: Woo Ju Yeon , Kang Young Soo , Kim Byung Kyu 
Published: May 2010

Abstract
The grating formation dynamics, SEM images, diffraction efficiency, and electrooptical properties of transmission grating of holographic polymer dispersed liquid crystals (HPDLCs) have been investigated by incorporating three different types of monofunctional reactive diluents into the host polymer matrices. A gradual increase of real time diffraction efficiency, a decrease of LC droplet size, and an increase of diffraction efficiency of the composite film were obtained with the addition of epoxy acrylate monomers due to the increased viscosity of polymer/LC mixtures leading to decreased droplet coalescence. In addition, epoxy acrylate monomers induced decreased volume shrinkage according to their ring structure with bulky group. Driving voltage increased with the addition of epoxy monomers whereas rise time and decay time decreased as a result of the decreased LC droplet size. At an optimum composition of epoxy monomer, a minimum switching voltage of 6 V µm−1 and rise time of 0.15 ms and a decay time of 18.05 ms were respectively obtained.
Effect of finger position on the median nerve area within the carpal tunnel: an ultrasound imaging study
Authors: Nadar Mohammed Shaban , Asbeutah Akram , Al-Obaidi Saud 
Published: May 2010

Introduction Finger flexion has been suggested to contribute to the aetiology of carpal tunnel syndrome (CTS). The purpose of this study was to measure the immediate effects of finger flexion on the cross-section area of the median nerve (MNA). Methods Thirty-one healthy volunteers participated in this experimental study. The MNA was measured at the level of hook of hamate using high-resolution ultrasonography during four different finger positions. Results A significant change in MNA during different finger positions was found ( F = 24.149, P < 0.001). The biggest difference in MNA was recorded between full finger extension and forceful finger flexion (mean difference = 1.29 mm2, P < 0.001). An inverse correlation between MNA and finger flexion was found (Pearson's r = −0.348, P = 0.002) where the MNA decreased as fingers moved toward flexion. Conclusion Finger flexion resulted in direct decrease in MNA, possibly contributing to median nerve compression. Clinical implications Hand therapists need to consider modifying their conservative treatment of CTS by limiting activities that require finger flexion and restricting the movement of the wrist and fingers to restrict finger flexion, thus limiting pressure increase on the median nerve.